Effect of metabolic state on phytohemagglutinin-P agglutination of normal human erythrocytes.

A reproducible quantitative assay for the lectin-mediated agglutination of human erythrocytes, depending on different rates of settling of agglutinated and nonagglutinated erythrocytes, was developed. This assay was used to study the aggregation of human erythrocytes by phytohemagglutinin-P. The aggregation of human erythrocytes by phytohemagglutinin-P was found to depend upon the metabolic state of the cells. Metabolically depleted erythrocytes agglutinated much less readily than did similar cells supplied with adenosine. This was not due to swelling and rigidity of the cells, since erythrocytes in hypotonic solution did not exhibit significantly altered phytohemagglutinin-P agglutination. Metabolically depleted erythrocytes, or erythrocytes from blood stored 8 weeks, lysed and resealed in the presence of ATP, were agglutinated by phytohemagglutinin-P to a much greater extent than control samples without ATP. The presence of Mg2+, either alone or with ATP, had little effect on the agglutinability of the resealed membranes. Low concentrations of Ca2+ (0.2 mM) had little effect on agglutinability, although high Ca2+ (5 mM) inhibited agglutinability of the resealed membranes somewhat. Both metabolically depleted erythrocytes and depleted erythrocytes, previously treated with adenosine, when treated with trypsin released similar amounts of sialic acid. The agglutinability of the trypsinized adenosine-supplemented cells increased more readily than did that of trypsinized metabolically depleted cells. The agglutination of erythrocytes was not affected by cytochalasin B (40 mug/ml). Vinblastine (0.2 mM) caused depleted erythrocytes to agglutinate similarly to adenosine-supplemented erythrocytes, but had no effect on the agglutination of adenosine-supplemented erythrocytes. It is concluded that ATP in the human erythrocyte probably participates in the modulation of phytohemagglutinin-P agglutinability. This is not a consequence of the more rigid membrane known to accompany ATP depletion in the erythrocyte, or of the effect of ATP levels on Ca2+ or Mg2+ content. It appears likely that ATP modulates human erythrocyte phytohemagglutinin-P agglutinability through interaction, direct or indirect, with a membrane-associated component, which might also be sensitivie to vinblastine.


Uterine chromatin template activity during the early stages of pregnancy in the rat.

1. The template activity of chromatin prepared from rat uterine nuclei during dioestrus, oestrus and the first 7 days of pregnancy has been examined. 2. The DNA, RNA, histone and non-histone protein contents of uterine chromatin remained constant during early pregnancy. 3. The rate of RNA synthesis on Day 1 uterine chromatin was 8.61 +/- 0.59 (mean +/- S.E.) pmol of UMP incorporated/mg DNA per 10 min. When compared with DNA prepared from rat liver nuclei, 13.20 +/- 0.27% (mean +/- S.E.) of the Day 1 chromatin DNA was available for transcription by Escherichia coli RNA polymerase. 4. Uterine chromatin from rats in early dioestrus had significantly less template activity than during oestrus. 5. Chromatin prepared from whole uterus on Day 5 and from implantation sites on Days 6 and 7 of pregnancy had a significantly higher template activity than chromatin obtained from uteri on Day 1. Chromatin from interimplantation tissue on Day 6 had a lower template activity than that from uteri on Day 1. 6. RNA - DNA hybridisation of RNA transcribed from chromatin obtained on Days 2, 5 and 7 of pregnancy showed that RNA transcribed from Day 5 chromatin obtained  species not present (or present in very small amounts) in RNA transcribed by chromatin from uteri on Day 2 and from implantation tissue on Day 7 of pregnancy. 7. The results are discussed in relation to the cellular changes occurring in the stroma immediately before implantation and it is postulated that the appearance of a new species of RNA on Day 5 is related to the preparation of the stromal cells for decidualisation.


Ornithine decarboxylase activity in relation to DNA synthesis in mouse interfollicular epidermis and hair follicles.

The relationship between ornithine decarboxylase (L-ornithine carboxylyase, EC 4.1.1.17) activity and DNA synthetic activity was studied in mouse epidermis. Interfollicular epidermis and hair follicles were investigated separately. It was found that, in hair follicles, the variations of DNA replicative activity, which are reflected in the cyclic growth of hair, are paralleled by corresponding changes in ornithine decarboxylase activity. In both interfollicular epidermis and hair follicles, stimulation of DNA synthetic activity by plucking of hair induced a rapid and marked increase in ornithine decarboxylase activity. The relationship of steady-state and induced ornithine decarboxylase activity to DNA synthetic activity was compared in hair follicles and interfollicular epidermis. A correlation between the activity of this enzyme and DNA replication was found thereby in each of these tissues.


Fractionation of plant aminoacyl-tRNA synthetases on tRNA-Sepharose columns.

It has been shown that tRNA-Sepharose, a chromatographic adsorbent containing unfractionated tRNA bound to a Sepharose matrix, is a useful, group-specific adsorbent for fractionation of the plant aminoacyl-tRNA synthetases. Conditions are described in which Val-, Trp-, Phe-, Leu- and Ile-tRNA synthetases from yellow lupin seeds can be separated from each other on the tRNA-Sepharose columns. Factors affecting affinity chromatography on the t-RNA-Sepharose columns are discussed. The affinity chromatography procedure for the purification of lupin Ser-tRNA synthetase to homogenity is described.


Isoaccepting species differences between polysome-bound and total cellular tRNA in SVT2 cells.

Reversed-phase chromatographic comparisons of total cellular tRNAs with tRNAs isolated from a polysome enriched cell fraction establish significant enrichments for specific isoaccepting species of tRNAIle, tRNALeu, tRNALys, tRNAMet and possibly tRNAA la. Similar comparisons of tRNAAsn, tRNAAsp, tRNAHis, tRNAPhe, tRNASer and tRNATyr have been performed as well; however, no prominent differences were observed.


Barrier to rotation and conformation of the NB2 group in cytosine and its derivatives. Part I. Theoretical study of cytosine.

A theoretical investigation of the conformation of the amino group in cytosine has been performed by the CNDO/2 and INDO methods. The results suggest that from the energetical point of view the conformation of the amino group is not stable in the course of rotation. It changes its hybridization from sp2-like in the planar case to sp3-like in the transition state. The physical basis of the barrier to rotation of this group around the C4-N7 bond are discussed. Some comments on the solvent dependence of the electronic absorption spectra of cytosine are presented.


Barrier to rotation and conformation of the -NR2 group in cytosine and its derivatives. Part II. Experimental and theoretical dipole moments of methylated cytosines.

The dipole moments of several cytosine, methylaminocytosine and dime-thylaminocytosine derivatives with and without an ortho methyl group were determined experimentally in dioxane and benzene. Calculations of total energies and dipole moments were performed by the CNDO/2 and INDO methods for sp2 and sp3 hybridization of exocyclic nitrogen for different values of rotational angle phiC-N. Comparison of the experimental dipole moments with those calculated for the energy minima suggests that the conformation of the dimethylamino group is not planar and differs from that found in cytosine. 1,5,7-Trimethylcytosine, with the dipole moment of 7 Deby units, was considered to be the model compound which closely reproduces the dipole moment of cytosine.


The half-life of polyadenylated polysomal RNA from normal and transformed cells in monolayer culture.

The small genotypic differences between normal and transformed cells are insufficient to account directly for all their wide phenotypic differences, which probably in some cases at least involve alterations in control of gene expression. To ascertain whether such alterations involved changes in mRNA stability, RNA half-lives were estimated in five monolayer cell lines, including two pairs of normal cells and their transformed counterparts. The results for the polyadenylated fractions in all cases fit with those expected from a model in which the whole fraction has a single half-life, of less than one generation time. From both the transformed/untransformed cell pairs, there is evidence that a relationship exists between cell generation time and the half-life of the polyadenylated polysomal RNA fraction, which persists even through the process of transformation. Considerable alteration in the pattern of RNA stability is therefore unlikely to be obligatory in in vitro transformation.


Stimulation of mitochondrial protein synthesis by metal ions.

1--10 muM Cu2+, Ag+, and Au3+ were found to stimulate rat liver mitochondrial protein synthesis in vitro. Cu2+ and Ag+ also produced an increase in mitochondrial volume ("swelling"). Thus, thyroid hormones and their analogs are not unique, as suggested previously (Buchanan, J.L., Primack, M.P. and Tapley, D.F. (1970) Endocrinology 87, 993--999), in stimulating both mitochondrial protein synthesis and swelling. Furthermore, the data suggest a role for Cu2+ in the regulation of mitochondrial protein synthesis.


Subcellular distribution and functional properties of different forms of elongation fractor EF1 from wheat embryos.

Elongation factor EF1 was found in a low salt homogenate of wheat embryos, either in the 100 000 X g supernatant or in the ribosome pellet. The ribosome-linked EF1 (EF1R), deteched by high salt washing, was purified to electrophoretical homogenetiy and its molecular and functional properties compared to those of a purified high molecular weight species of EF1 obtained from cytoplasm (EF1H). The two forms are associations of different polypeptides having in common only the polypeptide which can form the ternary complex with aminoacyl-tRNA and GTP. Whereas EF1R is able to fulfill all the EF1 functions, EF1H, incubated with ribosomes completely deprived of elongation factors, can catalyze the aminoacyl-tRNA binding to ribosomes, but, in the presence of EF2, forms only a very small amount of poly(Phe).


Sequence heterogeneity of the mini-circles of kinetoplast DNA of Crithidia luciliae and evidence for the presence of a component more complex than mini-circle DNA in the kinetoplast network.

Exhaustive digestion of the 0.76 mum mini-circles of the kinetoplast DNA from Crithidia luciliae with endonuclease HapII yields at least 37 fragments with an added molecular weight of at least 24-10(6), i.e. about 16 times that of the mini-circle. The DNA isolated from cloned cells yields the same digestion pattern. Endonuclease EcoRI cuts only part of the mini-circles in each network. This proves that mini-circles are not homogeneous in sequence. Digestion of total kinetoplast DNA with HapII yields, in addition to the mini-circle fragments, 7 fragments with an added molecular weight of 16-10(6). We conclude that these are derived from a minor component of the network, with a higher sequence complexity than the mini-circles.


The effect of ageing on in vitro fidelity of translation in mouse liver.

In a polyuridylic acid (poly(U)) stimulated in vitro assay, there is an age-related reduction in polyphenylalanine synthesis with mouse liver microsomes. As measured by the incorporation of leucine under the same conditions, old microsomes make fewer errors in translation than do young ones. Old microsomes have a higher requirement for Mg2+ than young for the optimal synthesis on both acids, suggesting an age-related deterioration in poly(U) complexing ability.


Incorporation of ortho[32P]phosphate into phosphatidylcholines and phosphatidylethanolamines in rat skeletal muscle.

1. The specific radioactivities of individual molecular species of muscle phosphatidylcholine and phosphatidylethanolamine have been measured by a combination of argentation thin-layer chromatography and countercurrent distribution. 2. The specific radioactivities of individual molecular species of muscle phosphoglycerides have been determined 3 h after intraperitoneal injection of ortho[32 P] phosphate. Under these conditions the specific radioactivities of the species present in rat muscle were found to be measures of the relative turnover times of these molecules. 3. The specificity radioactivity of phosphatidylcholine was approx. three times that of phosphatidylethanolamine. The 1-palmitoyl-2-oleoyl and 1-oleoyl-2-linoleoyl phosphatidylcholines had the fastest turnover and the 1-palmitoyl-2-arachidonoyl the slowest. Of the phosphatidylethanolamines, the linoleoyl and the docosahexaenoyl species showed the fastest turnover and 1-stearoyl-2-arachidonoyl the slowest. 4. The results indicate that phosphoglycerides in muscle turn over more slowly and more evenly than do liver phosphoglycerides.


Biosynthesis of phosphoglycerides in skeletal muscle in control rats and in rats deficient in essential fatty acids.

1. The specific radioactivities of individual molecular species of phosphoglycerides in the skeletal muscles of control rats and of rats deficient in essential fatty acids have been determined 3 h after intraperitoneal injection of ortho[32P] phosphate. 2. It has been demonstrated that the high average specific radioactivity of phosphoglycerides in muscles of rats deficient in essential fatty acids is due to both increased amounts and increased turnover of 1-palmitoyl-2-oleoyl phosphatidylcholine and phosphatidylethanolamine. 3. The 1-stearoyl-2-arachidonoyl phosphatidylcholine was found to turn over faster than the 1-palmitoyl-2-arachidonoyl species. In rats deficient in essential fatty acids, the 1-stearoyl-2-(5,6,11-eicosatrienoyl) phosphatidylcholine turned over more rapidly than the 1-palmitoyl-2-(5,8,11-eicosatrienoyl) species. Both findings are in constant with similar findings for liver.


Lipid composition of isolated epiphyseal cartilage cells, membranes and matrix vesicles.

1. Intact cells, cell fragments (membranes) and matrix vesicles were isolated from the proliferating and calcifying layers of epiphyseal cartilage by sequential hyaluronidase and collagenase digestion and differential centrifugation. Lipids were extracted and analyzed for various lipid classes and their fatty acid composition by column, thin-layer, paper and gas-liquid chromatography. 2. On a protein basis the isolated matrix vesicles had more total lipid than either the membrane or cell fractions, the vesicles and membranes being richer in non-polar lipids and containing smaller quantities of phospholipids than whole cells. Expressed as a percentage of the total lipid, the cells were richer in  triacylglycerols and lower in free fatty acids than in the membrane or vesicle fractions. The proportion of free cholesterol and the cholesterol/phospholipid ratio were nearly twice as high in the matrix vesicles as in the other tissue fractions. Choline and ethanolamine phosphoglycerides progressively declined in the membrane and matrix vesicle fractions, whereas serine phosphoglycerides and sphinogomyelin increased. Non-phosphorus-containing polar lipids were present in all fractions, the vesicles being richer in polyhexosyl ceramides, cerebrosides, glycosyldiacylglycerols and certain uncharacterized acidic polar lipids. 3. Fatty acid patterns of the matrix vesicles were distinctive from those of isolated cells, being generally richer in 18 : 0 and 18 : 2, and lower in 16 : 1 and 18 : 1 fatty acids. Monoacyl forms were similarly increased in 16 : 0 and/or 18 : 0, and reduced in 16 : 1, 18 : 1 or 20 : 2 fatty acids, depending on the lipid class. The fatty acid composition of diphosphatidylglycerol from cells and matrix vesicles was markedly different, providing evidence that the cardiolipin in the vesicles was not from mitochondrial components. 4. Based on the fact that the matrix vesicles were significantly enriched in free cholesterol, sphingomyelin, glycolipids and serine-phosphoglycerides, it is concluded that they are derived from the plasma membrane of the cell, supporting earlier conclusions based upon morphological and enzymological evidence.


Increased hepatic triacylglycerol secretion in fasted rats with ventromedial hypothalamic lesions.

Adult female rats with lesions in the ventromedial hypothalamic area and sham-operated controls were given Triton WR 1339 intravenously after 24 h without food for measurement of liver triacylglycerol secretion rate. Tritiated water was injected for measurement of lipogenesis in liver, perirenal and subcutaneous adipose tissues in vivo. The experiments were performed on unrestrained animals with a chronically implnted venous heart cannula after 24 h without food. By the use of this technique, anesthesia and handling of the animals during the experiments was avoided. The following differences in the lesioned animals compared to the sham-operated controls were found: relative hypertriglyceridemia. A significant increase of triacylglycerol accumulation in the plasma. Increased incorporation of 3H FROM 3H20 into liver fatty acids. The experiments demonstrate that hepatic lipid synthesis during fasting is greater in the lesioned than in the control animals, but not high enough to account for the increased triacylglycerol secretion. A shift in the hepatic metabolism of fatty acids, leading to greater triacylglycerol formation at the expense of other processes is therefore suggested. The possible role of insulin in these metabolic changes is discussed.


Correlation of rat liver chromatin-bound free and esterified cholesterol with the circadian rhythm of cholesterol biosynthesis in the rat.

Cholesterol has been shown to be present in rat liver chromatin isolated by methods designed to avoid contamination by membrane fragments. Evidence that the cholesterol was actually a component of chromatin includes (a) the constancy of the amount (1.30 +/- 0.14 mug per mg DNA), (b) the striking difference in the ratio of free (i.e. unesterified) to esterified cholesterol between that in chromatin and that in membrane, and (c) the rapid and marked changes which occurred in this ratio during the circadian cycle in chromatin but not in membranes. Although the total amount of chromatin-bound cholesterol did not change throughout the circadian cycle, the concentration of free cholesterol increased sharply a short time before the peak of cholesterol synthetic activity was reached at about midnight; it reached a basal level about 6 h later at approximately the same time the rate of synthesis returned to its basal level. When labelled cholesterol was administered by stomach tube, it was detectable within 2 h in whole nuclei and in chromatin, indicating that chromatin-bound cholesterol is rapidly exchangeable with that in liver cytoplasm and in blood plasma. Removal of basic proteins from chromatin did not result in the loss of any cholesterol, but removal of most of the acidic as well as the basic proteins resulted in loss of most of the chromatin-bound cholesterol. These results indicate that cholesterol is bound either to the acidic proteins or to both the acidic proteins and DNA. The data are compatible with the hypothesis that cholesterol biosynthesis controlled at the nuclear level and suggest that the relative amounts of free and esterified cholesterol associated with chromatin may play a role.


Inhibition of rat liver cholesterol esterase by local anaesthetics.

1. A number of local anaesthetics was shown to inhibit rat liver cholesterol esterase activity towards radioactively labelled cholesterol oleate. The anaesthetics inhibited in the order dibucaine greater than chlorpromazine greater than tetracaine greater than benzocaine greater than procaine greater than lidocaine greater than cocaine. 2. The mode of inhibition was seen to be non-competitive with respect to the substrate and is probably independent of any involvement of Ca2+. 3. The inhibition by tetracaine is partially reversed by sodium deoxycholate. However, all ionic and non-ionic detergents studied, sodium deoxycholate, sodium taurocholate, Triton X-100, and cetyltrimethylammonium bromide are capable of inhibiting the rat liver cholesterol esterase in a concentration dependent manner. Only sodium taurocholate stimulates enzymic activity.


Chemical structure of monosialoganglioside GM1b biosynthesized in vitro.

The structure of a neuraminidase-labile monosialoganglioside which is formed in vivo from asialoganglioside (galactosyl (beta, 1 in equilibrium 3) N-acetylgalactosaminyl (beta, 1 in equilibrium 4) galactosyl (beta, 1 in equilibrium 4) glucosyl (1 in equilibrium 1) ceramide) and cytidine-5'-monophospho-N-acetylneuraminic acid in the presence of young rat brain sialytransferase has been established. This monosialoganglioside contains a neuraminidase-labile N-acetylneuraminyl group which is linked at position C-3 of the terminal galactosyl unit. This result was obtained by ultramicro scale permethylation of radioactive neuraminidase-labile monosialoganglioside biosynthesized from asialoganglioside labeled with tritium in the terminal galactose.


Isolation and characterization of undersulphated chondroitin-4-sulphate from normal human plasma.

The present study was undertaken in order to characterize further the glycosaminoglycans of normal human plasma. Coagulation factor IX concentrate prepared from undiluted plasma by DEAE-Sephadex chromatography was used as the starting material. The concentrate was subjected to proteolytic treatment with papain and pronase, deproteinised with trichloroacetic acid, dialysed and passed through an AG 1 X 2 anion-exchange column. Glycosaminoglycans were eluted stepwise from the column with NaC1. The sole glycosaminoglycan obtained was an undersulphated chondroitin-4-sulphate which was identified by chemical analyses, digestibility with testicular hyaluronidase, electrophoretic behaviour and infrared spectrum. Gel-exclusion chromatography indicated a molecular weight of 17 000 for the compound. The undersulphated chondroitin-4-sulphate was calculated to represent at least 80% of the macromolecular glycosaminoglycans present in normal human plasma and to occur in a concentration of approx. 3 mg hexuronate per 1 of plasma.


Beta-Elimination and sulfite addition reaction of chondroitin sulfate peptidoglycan and the peptide structure of the linkage region.

Pronase digestion of bovine tracheal cartilage yielded acid mucopolysaccharide - peptide complexes which were fractionated by chromatography on Dowex 1(C1-). A major fraction was eluted with 1.5 M NaC1 and presumed to by chondroitin  sulfate A-peptidoglycan by cellulose acetate electrophoresis. Alkaline beta-elimination and sulfite addition reaction of this fraction yielded cysteic acid-containing peptides, two of which were obtained in an homogeneous state. The sequence determination of these two made it possible to remodel their original structures as Leu-Pro-Ser-Gly-Glu-Gly-Pro-Glu and Leu-Pro-Ser-Gly-Glu, where the serine residues carried polysaccharide chains. Together with the reported data on the polysaccharide-protein linkage region, the present result suggests that the -Ser-Gly- sequence is a minimum requisite for the glycosylation of serine residues in the protein core of various proteoglycans.


Adenine nucleotide metabolism in relation to purine enzymes in liver, erythrocytes and cultured fibroblasts.

To evaluate the regulation of adenine nucleotide metabolism in relation to purine enzyme activities in rat liver, human erythrocytes and cultured human skin fibroblasts, rapid and sensitive assays for the purine enzymes, adenosine deaminase (EC 2.5.4.4), adenosine kinase (EC 2.7.1.20), hyposanthine phosphoribosyltransferase (EC 2.4.28), adenine phosphoribosyltransferase (EC 2.4.2.7) and 5'-nucleotidase (EC 3.1.3.5) were standardized for these tissues. Adenosine deaminase was assayed by measuring the formation of product, inosine (plus traces of hypoxanthine), isolated chromatographically with 95% recovery of inosine. The other enzymes were assayed by isolating the labelled product or substrate nucleotides as lanthanum salts. Fibroblast enzymes were assayed using thin-layer chromatographic procedures because the high levels of 5'-nucleotidase present in this tissue interferred with the formation of LaCl3 salts. The lanthanum and the thin-layer chromatographic methods agreed within 10%. Liver cell sap had the highest activities of all purine enzymes except for 5'-nucleotidase and adenosine deaminase which were highest in fibroblasts. Erythrocytes had lowest activities of all except for hypoxanthine phosphoribosyltransferase which was intermediate between the liver and fibroblasts. Erhthrocytes were devoid of 5'-nucleotidase activity. Hepatic adenosine kinase activity was thought to control the rate of loss of adenine nucleotides in the tissue. Erythrocytes had excellent purine salvage capacity, but due to the relatively low activity of adenosine deaminase, deamination might be rate limiting in the formation of guanine nucleotides. Fibroblasts, with high levels of 5'-nucleotidase, have the potential to catabolize adenine nucleotides beyond the control od adenosine kinase. The purine salvage capacity in the three tissues was erythrocyte greater than liver greater than fibroblasts. Based on purine enzyme activities, erythrocytes offer a unique system to study adenine salvage; fibroblasts to study adenine degradation; and liver to study both salvage and degradation.


Serum-induced inhibition of isotonic fluid absorption by the kidney proximal tubule. III. Further evidence that complement-mediated cell lysis is involved.

The results of our previous studies have suggested that serum-induced inhibition of proximal tubular fluid absorption is due to complement-induced lysis of the tubular cells. The present study provides further evidence in support of this idea as well as other information pertinent to the mechanism of complement activation in vivo. 1. The electrical resistance of the luminal brush border membrane is reduced drastically concomitantly with a drop in cell potential difference when serum is perfused intraluminally. 2. Human C1 inhibitor (30-50 units/ml) does not significantly affect the inhibitory activity of human serum on fluid absorption, suggesting the non-involvement of the classical pathway. 3. Reactive lysis reagents (C56, C7, C8 + C9) partially inhibit fluid absorption when infused into the lumen. 4. In contrast to our previous report (Sato, K. and Ullrich, K.J. (1974) Biochim. Biophys. Acta 354, 182-187), very fresh serum, 10-times diluted can inhibit fluid absorption if perfused for 10 min. 5. Both mouse and guinea pig serum, which are normally inactive, are activated to attack the tubular cells if 1/100 volume rat or rabbit serum is added to them No such activation occurs by mixing guinea pig serum and mouse serum. The available data suggest that the presence of the later complement components but not the heat-labile factor (Factor B) or C3PA or C1 in the added serum is a prerequisite for mouse and guinea pig sera to be activated to inhibit fluid absorption.


Metabolic actions of vasopressin, glucagon and adrenalin in the intact rat.

Metabolic effects of vasopressin, glucagan and adrenalin were compared, in intact rats, especially in regard to time courses of effects. Hyperglycaemia was transient in response to vasopressin, prolonged following adrenalin, and, suprisingly, was not discernible after glucagon, except in response to a very large dose. Vasopressin decreased and adrenalin increased, the plasma free fatty acid concentration; both hormones decreased the triacylglycerol level. Muscle glycogen concentrations, measured in heart, diaphragm and skeletal muscle, exhibited small changes, with complex time courses, following hormone administration. Vasopressin brought about a rapid but transient activation of heaptic glycogen phosphorylase which resembled that due to adrenalin. The activation by glucagon of phosphorylase was greater and more prolonged, despite the absence of hyperglycaemia. In response to vasopressin, there was in increase in plasma insulin. Incorporation of 14C from [14C]glucose into glycogen or fatty acids was not influenced by vasopressin. Taken together, these results may be explained by rapid metabolic action of vasopressin on hepatic glycogenolysis, whereas adrenalin has multiple prolonged actions.


Carbohydrate composition of horse spleen ferritin.

The carbohydrate composition of horse spleen ferritin was studied. 1 mol of the apoferritin, the protein moiety of ferritin, contains 25 mol of hexose, 3 mol of hexosamine and 10 mol of fucose. Same carbohydrate composition was detected in the apoferritin from iron rich ferritins. These results indicate that horse spleen ferritin is composed of non-identical subunits as regards its carbohydrate composition.


The effect of digitonin of the stimulation by insulin of glucose uptake by isolated fat cells.

The effect of digitonin on glucose uptake by isolated fat cells in the presence and absence of insulin has been studied. At low concentrations of digitonin, the stimulation of glucose uptake by insulin was inhibited without severe cell damage as estimated by the leakage of lactate dehydrogenase from the cells. The inhibition of the insulin effect was not reversed by washing the cells or by the addition of cholesterol or lecithin-cholesterol liposomes to the incubation medium of the cells after treatment with digitonin. Cholesterol was shown to be present in the fat cells and it is suggested that the inhibition of the insulin effect is a consequence of the formation of digitonin-cholesterol complexes in the fat cell plasma membrane. Possible ways in which this may results in inhibition of the effect of insulin are discussed.


Induction of UDPglucose dehydrogenase during development, organ culture, and exposure to phenobarbital. Its relation to levels of UDPglucuronic acid and overall glucuronidation in chicken and mouse.

Liver UDPglucose in early chick-enbryo has, by the 19th day of incubation, reached levels existing in young hatched (White Leghorn) chicks. In developing ASH/TO mouse liver, the dehydrogenase is low, but increases sharply at late foetal and weaning stages; adult activity is greater in females than males. The UDPglucuronic acid content of embryo liver from at least 12 days resembles that of adult chicken; in mouse liver it rises over birth and infancy. These differences in relative rates of development of enzyme and nucleotide in the 2 species can explain why overall glucuronidation by liver appears in chick rapidly after hatching, but in mouse only gradually during infancy. UDPglucose dehydrogenase increases in embryo liver, probably by induction, 2-3-fold during culture with phenobarbital and some 5-fold when exposed to the drug in ovo. Phenobarbital treatment also increases the enzyme in late foetal and adult mice, abolishing the sex difference. Differences between induction of UDPglucose dehydrogenase and UDPglucuronyl transferase during development, culture and phenobarbital treatment indicate that control mechanism for these two enzymes are not directly linked.


Effect of estrogen on synthesis of glucose-6-phosphate dehydrogenase in R3230AC mammary tumors and uteri.

The effect of estrogen on synthesis of glucose-6-phosphate dehydrogenase (D-Glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) in the R3230AC mammary adenocarcinoma of ovariectomized Fischer rats was investigated. Enzyme synthesis was estimated by techniques using immunochemica precipitation and isolation of enzyme protein from tissues of rats that had been given radioactive leucine prior to sacrifice. The antibody-enzyme complex was dissociated and glucose-6-phosphate dehydrogenase was isolated after electrophoresis on sodium dodecyl sulfate-acrylamide gels. Administration of estradiol-17beta produced a two-fold increase in glucose-6-phosphate dehydrogenase activity, which was preceded by a five-fold increase in specific synthesis of glucose-6-phosphate dehydrogenase in R3230AC tumors. At least a 15-fold increase in enzyme synthesis was observed in the uterus. The rate of enzyme degradation (t 1/2) in the tumor was estimated at 17 h. These data indicate that the estrogen-induced increase in glucose-6-phosphate dehydrogenase activity was due to a de novo increase in enzyme synthesis.


The effect of dietary protein on the excretion of alpha2u, the sex-dependent protein of the adult male rat.

Adult male rats were maintained on normal (20% casein), protein-free (0% casein), high protein (50% casein), decicient protein (20% zein), and a supplemented, deficient protein (20% zein plus L-lysine and L-tryptophan) diets. Rats on a protein-free diet excreted approximately 1 mg alpha2u/24 h compared with a normal of 10-15 mg/24 h. Depleted rats placed on a 20% casein diet showed a rapid restoration of the normal alpha2u excretion as well as total urinary proteins. Accumulation of alpha2u in the blood serum was measured in nep-rectomized rats. Rats on a 0% casein diet accumulated only 30% of the alpha2u compared to normals. On a 50% casein diet, rats excreted 30-50 mg alpha2u/24 h. However, the accumulation was normal in the serum of nephrectomized rats. A high protein diet did not stimulate alpha2u synthesis but probably increased the renal loss of all urinary proteins. The excretion of alpha2u on a zein diet was reduced to the same degree as with the protein-free diet. Supplementation with lysine and tryptophan restored the capacity to eliminate alpha21 to near normal levels. Accumulation of alpha2u in the serum of nephrectomized rats kept on the zein diets showed that the effect to suppress the synthesis of the ahpha2u. Supplementation restored the biosynthesis of alpha2u. We conclude that the effect of dietary protein on the excretion of urinary proteins in the adult male rat is caused in large part by an influence on the hepatic biosynthesis of alphay2u. The biosynthesis of this protein, which represents approximately 30% of the total urinary proteins, is dependent on an adequate supply of dietary protein.


Hepatic and extrahepatic N-acetyltransferase. Perinatal development using a new radioassay.

We report a sensitive and rapid radioassay method for p-aminobenzoic acid N-acetyltransferase. The principle of this assay involves acetylation of p-aminobenzoic acid with [1-14C] labeled acetyl coenzyme A and direct extraction of enzymically formed radioactive p-acetamidobenzoic acid into nonaqueous scintillation fluid. Using this radiometric assay, hepatic and extrahepatic tissue distributions from rat and rabbit were studied. Rabbit blastocyst and endometrial N-acetyltransferase specific activities were equivalent to hepatic activities. Perinatal development studies in rats and rabbits revealed that fetal and neonatal animals are capable of N-acetylation. Rat liver developmental studies exhibited two peaks of activity with the first peak occurring in the late fetus followed by a second peak 3 days after birth. Rabbit fetal and neonatal enzyme activity increased to adult levels by the second week after birth in liver and gut, however, lung showed a different developmental pattern. These studies demonstrate that fetal extrahepatic tissues, like adult tissues, play an important role in N-acetylation.


X-ray photoelectron spectroscopy of some selenium containing amino acids.

X-ray photoelectron spectra of some inorganic selenium compounds, Se-methionine, Se-cystine, Se-urea and selenodicysteine were recorded and compared with the XPS data obtained from the respective sulphur containing compounds. The oxidation state of selenium could be monitored by the observed chemical shifts of the Se(3p1/2),Se(3p3/2) and Se(3d3/2,5/2) levels. Though having a formal oxidation state near zero, the binding energy of the core electrons of Se in Se-methionine, Se-cystine and selenodicysteine was shifted by 0.4, 0.7 and 0.4 eV, respectively. This phenomenon was attributed to the rather distinct polarization of Se. The reversible oxidation of Se-cystine using H2O2 and NaBH4 could be successfully demonstrated by this XPS-technique.


Platinum complexes of nucleotides.

The reaction of [Pt(dien)Cl1Cl (dien = NH2CH2CH2NHCH2CH2NH2) with nucleotides has been studied by nuclear magnetic resonance. It has been found that the CMP (cytidine 5'-monophosp-ate) and GMP (guanosine 5'-monophosphate/coordinate to the platinum atom through N3 and N7, respectively. The reaction of the platinum salt with the nucleotide is complete when one to one ratio of platinum to nucleotide is used and no evidence of phosphate group binding to platinum has been found. No additional binding sites have been detected except the N7 site on the guanylic group of GMP even in the presence of a large excess of [Pt(dien) Cl1Cl. The AMP (adenosine 5'monophosphate] coordinates to the platinum at the N1 and/or N7 sites. The reaction of AMP and platinum is complete is complete at a ratio of four platinum to one AMP.


DNA-platinum interactions in vitro with trans- and cis-Pt(NH3)2Cl2.

In the present study the nature and the hydrolysis of DNA-Pt complexes with the platinum compounds, [Pt(dien)Cl]Cl, trans- and cis-Pt(NH3)2Cl2, using potentiometric chloride determinations, have been investigated. The trans-Pt(NH3)2Cl2 and the [Pt(dien)Cl]Cl react with the GC planes at the N7(G) sites, while the cis-Pt(NH3)2Cl2 compound reacts with the GC planes and forms a chelate by using the N7(G) and O6(G) sites. The complex is a specific 1:1 Pt:DNA adduct. The platinum atom in cis-Pt(NH3)2Cl2 liberates both chlorine atoms on chelation. A mechanism for the in vivo antitumor activity of the cis-Pt(NH3)2Cl2 is proposed and the structure activity relationship is discussed.


beta-Decarboxylation of L-aspartic acid: a metal chelate-catalyzed reaction.

beta-decarboxylation of L-aspartic acid was observed in the system, pyridoxal: L-aspartic acid:aluminum(III), 1:100:1 when heated at 80 degrees for three hours. This reaction was followed by electronic spectroscopy and showed quantitative conversion of pyridoxal to pyridoxamine indicating decarboxylation of the ketimine. alpha-Methyl-L-aspartic acid was not decarboxylated indicating the presence of the alpha-proton and prior transamination as requirements for decarboxylation. When pyridoxamine and oxalo-2-propionic acid were reacted at pD 4.60, product analysis by nmr showed the presence of pyridoxamine and alpha-ketobutyric acid, indicating hydrolysis of the decarboxylated ketimine. Decarboxylation was fast compared to spontaneous decarboxylation. A mechanism is proposed for non-enzymatic decarboxylation and the previously suggested mechanism for the inactivation of the enzyme aspartate beta-decarboxylase is discussed.


[Isolation and physical chemical properties of rat hemopexin].

Rat hemopexin was purified by a procedure involving three different steps : ammonium sulfate precipitation, rivanol precipitation and DEAE-cellulose chromatography with concave gradient of molarity. Purity of the preparation was checked by three different methods : analytical ultracentrifugation, immunoelectrophoresis and acrylamide gel electrophoresis. The principal physical properties were studied. The amino acid and carbohydrate composition was determined and compared with that of human and rabbit hemopexin.


[Characterization and physico-chemical properties of human transcortin].

The molecular weight of human transcortin, calculated from the sedimentation coefficient, was found to be 49,500, thus slightly lower than previously reported values. After purification, human transcortin trended to polymerize rapidly, with participation of both non covalent bonds and one disulfide bridge per dimer. The physicochemical parameters, the amino-acid and carbohydrate composition were determined; its stability was studied under different conditions. Preliminary structural studies showed that the N-terminal sequence of the polypeptide chain was: Met-Asp-Pro-Asn-Ala-Ala-Tyr-Val and that the C-terminal amino acid was leucine.


[Primary structure of the alpha chain of the major component of goose hemoglobins (Anser anser)].

Utilising the homology between goose alpha chain hemoglobin and chicken, the primary arrangement of the amino acid residues of the alpha chain (major component) of goose hemoglobin is presented. Data were obtained from amino acid analysis of the isolated alpha chain and of tryptic peptides of the chain. Their chemical structure was established by Edman degradation, carboxypeptidase A and B and leucineaminopeptidase digestion.


Kinetic amplification of enzyme discrimination.

The dependence of the accuracy of enzymatic systems on the mechanism of the catalyzed reaction is investigated, using a probabilistic approach. Certain mechanisms of reaction, involving a delay in one of the steps act as kinetic amplifiers of molecular discriminations. The relationship between our scheme for a delayed reaction [1] and Hopfield's scheme [i] is discussed.


[Purification and chemical study of a Collocalia glycoprotein].

A glycoprotein was purified from the aqueous extract of "edible bird's nest" (Collocalia) using free flow preparative electrophoresis and represented the main fraction of Collocalia glycoproteins. This glycoprotein is homogeneous upon agarose electrophoresis and slightly polydisperse upon ultracentrifugation (S So 20w = 3,0). The carbohydrate moiety contains galactose, mannose, glucosamine, galactosamine and sialic acid, which is completely released by Clostridium perfringens or Diplococcus pneumoniae neuraminidases and has the same chromatographic behaviour as N-acetyl-neuraminic acid. The peptide part of the glycoprotein is rich in serine, threonine and proline. About 40 p. cent of the hydroxyaminoacids are involved in carbohydrate-peptide linkages.


[Comparative metabolism of phospholipids of osmoregulation effector organs in European eel (Anguilla anguilla)].

The phospholipid composition from various organs of the fresh water eel, such as gill, kidney, gut, liver and muscle, were determined by thin-layer chromatography. The major phosphatides found in these tissues were PC, PE and SPH and minor constituents PS, PI, DPG, AP and also LPC in the gut. A greater percentage of PS and SPH occurs in the osmoregulatory effector organs such as gill, kidney, and gut. From in vivo comparative kinetic studies of the 32P incorporation into the phospholipids, between 6 and 48 hours, certain remarkable features of phospholipid metabolism have been found in these tissues. A low uptake of inorganic 32P into the tissue lipid phosphorus was observed in the eel at 15 degrees C. The specific activity of the lipid phosphorus increased continuously in all tissues during 48 hours after 32P injection. During this experimental period, phosphatidic acid and phosphatidyl inositol fractions were labelled most rapidly in gill, kidney and gut, while the specific activity of the phosphatidyl choline fraction remained low in these organs. In liver, the rate of PC formation appears to be faster than the PI and PE biosynthesis. In gill and gut, the PE showed greater turnover than the PC as measured by 32P incorporation. In the eel, an euryhalin fish, the DPG of osmoregulatory effector organs has a high specific activity at all times. PS showed only a high specific activity in the gill. Labelling  of SPH occured slowly in the various tissues only becoming evident after 24 hours. The results are compared with those published for other poikilotherm and homeotherm vertebrates. Relative differences between the turnover of various tissue phosphatides are discussed with of reference to the general scheme on phospholipid biosynthesis and to the physiological functions of the various organs.


Production of CO2 in the living mouse immediately after injection of 1- or 2-14C acetate.

Three groups of mice, normally fed, fasted and fed after a fasting period are injected intravenously with either 1- or 2-14C acetate. The respiratory 14CO2 as well as that of the liver, the adipose tissue and the carcass are collected after 3 min and the radioactivity measured. A determination is also made of the radioactivity of the tissue fatty acids and, for two groups of mice, of the circulating glucose. A calculation is suggested by which the number of revolutions performed by the acetate C in the Krebs cycle before it is transformed into CO2 can be deduced. The results suggest that the Krebs cycle is very open, that the acetate C found in the glucose has already broken away from the cycle after one revolution and that the C which appears in the form of CO2 has performed an average of only 2.8 to 3.6 revolutions. The results are evaluated as a function of the experimental conditions chosen.


[Fluorescence study of lymphocyte plasma membranes].

ANS binding parameters--dissociation constant, number of binding sites, rotation freedom--are measured by fluorescence studies of a complex between ANS and lymph node cell plasma membranes. Divalent ions, Mg++ and Ca++, enhance the complex fluorescence intensity without shifting its maximum wavelength : this enhancement is induced by affinity and quantum yield increases, while the number of binding sites remains constant. The complex fluorescence quenching by ethacrynic acid shows the presence of free SH groups in the ANS binding site. An energy transfer takes place between membrane protein tryptophan residues and bound ANS ; the energy transfer yield is unaffected by Ca++ ions. A correlation of these results is postulated with the biological activity of the membrane.


[Influence of glyoxylic acid on properties of isolated mitochondria].

Glyoxalate is an effector of oxidative phosphorylation in isolated mitochondria : it slows down State 3 but does not affect State 4 respiration. This report presents the findings of our study on the mechanism of action of glyoxalate ; these findings are listed below. The inhibition of Stage 3 respiration by glyoxalate does not set in immediately, can be reversed in part by the addition of an uncoupling agent or a dithiol, is non-competitive against succinate and can be demonstrated with substrates requiring the involvement of other membrane transport systems. Glyoxalate prevents the increased oxygen uptake stimulated by 2,4-DNP or Sr++. Glyoxalate also inhibits phosphate transport and this inhibition can account for most of the effect observed. The inhibition of State 3 respiration is paralleled by a decrease in the mitochondrial accumulation of succinate : this decrease could arise from a direct effect of glyoxalate on dicarboxylic acid transport or could be the result of an inhibiton of the phosphate transport system, which is connected with the former. The decrease in the respiratory rate of uncoupled mitochondria placed in a phosphate free medium demonstrates that the effector acts directly at the substrate transport or/and electron transfer level. Phosphate, by delaying the respiratory inhibiton due to glyoxalate, has a protecting effect on mitochondrial functions. Glyoxalate is thus acting at several mitochondrial sites. It acts presumably by forming hemimercaptals, blocking sulfhydryl groups. Its effects can be accounted for by the unfolding of such (hemicercaptal) groups under the influence of ADP, Pi, uncoupling or others agents which bring about conformational changes in the internal mitochondrial membrane.


Developmental aspects of galactose-1-phosphate uridylytransferase in rat intestine.

Kinetic and developmental characteristics of rat jejunal galactose-1-phosphate uridylyltransferase have been examined. Km values for the substrates galactose-1-phosphate and uridine diphosphate (UDP) glucose were the same for both the newborn and adult rat enzymes, although the Vmax of the enzyme in newborns was about threefold higher than that of the adult rat. Equal enzyme activity was present in the villus, crypt cells and the muscularis of adult jejunum. The specific activity of the enzyme remained relatively uniform (V about 20 nmoles/min/mg protein) until 18 days of age when the velocity of the reaction began to decrease. The adult value at 42 days of age is about one fifth of that in the young. The pattern of change of specific activity was compared with that for galactokinase and UDP-galactose-4-epimerase, and the observations suggest separated regulatory factors for each enzyme. The total activity of the galactose-metabolizing enzymes in jejunum was also calculated. In the young, transferase has the highest activity, but in the adult, epimerase activity is highest. Jejunal galactokinase activity is low throughout the developmental period which suggests that phosphorylation of galactose may be the limiting step in intestinal metabolism of the sugar.


Development of the neonate opossum (Didelphis virginiana).

This study describes the postnatal growth and development of the opossum (Didelphis virginiana). Measurements were made weekly on 6 young opossums between 50 and 189 days following birth. These measurements included: total length, length of ear and tail, and length of front and rear appendages. Body weight measurements were extended to 233 days. The mean body weight at 50 days was 14.1 g, which increased rapidly to 2,560 g at 233 days.


The influence of diets deficient in energy, or in protein, on conceptus weight, and the placental transfer of a non-metabolisable amino acid in the guinea pig.

The effect on the guinea pig conceptus of feeding the mother diets deficient in energy or in protein has been investigated. Fetal uptake of a labelled non-metabolisable amino acid, amino-isobutyric acid, injected into the maternal blood stream, was studied at the end of gestation. Both diets retarded fetal growth, influencing litter number and fetal and placental weight. The relationship between fetal and placental weight was similar in the control and restricted-calorie animals, and the transfer studies showed that placental function and fetal uptake per unit weight was similar in the two. Feeding a low-protein diet caused the ratio between fetal and placental weight to increase; enhanced placental transfer and fetal uptake also suggested the possibility of adaptation when the calorie supply is adequate.


Effects of goat anti-rat placenta IgG on the in vitro uptake of 125I-labeled human serum albumin by the rat visceral yolk sac.

Preincubation of rat visceral yolk sac with goat anti-rat placenta IgG and following incubation with 125I-HSA resulted in a reduction of the uptake of albumin by 30-50% in comparison with the controls. Inhibitors of respiration or glycolysis impair the ingestion of protein, likewise the reduction of the incubation temperature.


Metabolic patterns in several tissues of newborn rabbits during ischemia.

The metabolic states of various tissues of newborn rabbits were studied before and after periods of ischemia of 5-40 min. The contents of substances of the energy distributing adenylic acid-creatine phosphate system as well as glycogen, glucose and lactate were determined and the results are discussed in comparison with the well-known values from ischemic tissues of adult rabbits. The preservation of high energy phosphates as well as the rate of glycolytic energy production during the course of ischemia was quite identical in the myocardium of newborns and adults in contrast to the different ability of newborn and adult rabbits to maintain circulation in anaerobic conditions. In the central nervous system the ATP contents decreased to very low levels within a few minutes in both groups although the glycolytic energy production was rather different. But the larger amounts of adenine nucleotides present in the newborns at any time of ischemia indicate a better chance of postischemic recovery. In the livers and the kidneys of the newborns higher rates of glycolytic energy production led to better preservation of the energy-rich substances while in skeletal muscle and the lung only slight differences occurred between newborns and adults.


Blood glucose, serum insulin and glucagon response to arginine in premature infants.

The effect of arginine infusion on the peripheral blood sugar, plasma insulin and plasma glucagon was studied in 28 appropriate-for-gestational-age premature newborn infants, 1-day-old, and in 12 normal children 4-10 years old. In the premature plasma insulin and glucagon concentrations increased after arginine though less noticeably than in the older children, and their insulin/glucagon molar ratio was low at fasting and did not change after arginine. It is assumed that the endocrine pancreatic activity is already developed at birth and adequate to the metabolic state in neonatal life.


Physiology of the artificial heart.

Numerous deviations from normal physiology formerly ascribed to artificial heart pumping actually resulted from experimental artifacts. Recent results indicate that infection, thromboembolism, pulmonary pathology, and renal deterioration could be considered mostly nonspecific artifacts of mechanical heart implantation. Nonetheless, damage to the blood constituents and hepatic congestion seemed to be specific effects of artificial heart pumping. Hemolysis correlated to pumping sac collapse, low cardiac output, and hematocrit value (r = .912, p is less than .001). Hepatic congestion, caused by pulsatile venous hypertension and hypervolemia, was postulated to result from functional atrial volume restriction (small atrium syndrome).


Resorption of 125I-labeled fibrin bioplast from the dorsal muscle of rats.

Fibrin bioplast is an implant material made from plasticized fibrin. The resorption and route of elimenation of 125I-tagged bioplast plates implanted into the back muscle of rats have been studied in 18 experiments. Variation in radioactivity of the implant, appearance of the activity in the urine and fecal output, supplemented with information on the radioactivity of the implant site and that of isolated organs, reveal that the elimination of bioplast begins on the 12th day and proceeds at an even rate without pathological tissue reactions. By the 42nd day 10 to 12% of the original material is present. The elimination of the implant material is complete and occurs mainly with urine through the kidneys.


Nonthrombogenic ac polarized copper prosthesis.

In previous studies from our laboratories, it was shown that metals and alloys which register negative potentials in blood vs the normal hydrogen electrode tend to be antithrombogenic while those with positive potentials are invariably thrombogenic. The present paper deals with a novel approach of maintaining an implanted metallic prosthesis at a negative potential. A copper vascular prosthesis in a dog was maintained at cathodic potentials by a small amplitude (+/- 10 mV) high-frequency ac (100 kHz) on the prosthesis. The prostheses were removed after 2 hours, 6 hours, 1 day, and 42 days, with subsequent visual and scanning electron microscopic examination of the prostheses completed. All tubes were free of thrombus deposits. Minimal junctional thrombi were found, probably due to differences in physicochemical characteristics of the vascular prostheses and recipient vessels. The results are compared with those in the control group (copper tubes with no current) and dc polarized copper tubes. While the control tubes occluded in 2 to 6 hours, the dc and ac polarized tubes remained patent. Of the ac and dc polarized tubes, the former tubes lasted up to 6 weeks with less thrombus deposit. The mechanism of operation of the ac polarized copper prosthesis is not fully understood.


Histologic evaluation of vitreous carbon endosteal implants in occlusion in dogs.

A 6-7 month histologic study of vitreous carbon endosteal implants in occlusion was conducted in dogs to determine whether the shape of the implant has adverse effects on supporting tissues. Conical vitreous carbon implants were placed in fresh, second, and third premolar extraction sites, and the sites were allowed to heal for periods of 2 to 8 weeks prior to restoration with cast gold crowns. Gingival tissues healed routinely and showed inflammatory conditions similar to tissues adjacent to teeth, and normal sulculur depths were measured. Bone formation was observed within grooves in the implant surface, providing retention and stabilization, normal bone remodeling appeared to be occurring adjacent to the implant sites. No inflammatory responses, foreign body reactions, or infections were observed. Vitreous carbon appears well suited for application as an endosteal implant material.


Prediction of the strength of the neck of femur from its radiological appearance.

In this study 39 male and female cadaveric femoral necks of ages between 21 and 89 years have been radiographed and subsequently mechanically tested to determine failure load. A structural model has been developed, in an attempt to predict the failure load of specimens solely from measurements made from an anteroposterior radiograph of the neck region. Good correlation was obtained between the predicted and experimental values for the range tested. The influence of average bone porosity is discussed. It is believed that this method, with modifications will provide a basis for the quantitative assessment of femoral neck strength in the clinical situation.


A basic design of a chair for hemiplegics with special reference to the back shape.

The seating requirements of hemiplegic patients are studied extensively in the light of ergonomic principles and with the co-operation of the staffs and patients of 25 hospitals in the UK. It is suggested that the provision of a suitably contoured back and seat shape would greatly reduce the need to use other supporting mechanisms in order to seat the patient comfortably and effectively. Plans are given for a chair which should provide integrated support for the patient although no constructional plans are given. The back shape is designed with the aid of data from a survey of elderly people's back shapes and it is hoped that this part of the design will find application in chairs for geriatric patients generally. First, however, it is necessary thoroughly to test the design under working conditions.


Automatic indirect sphygmomanometry.

After discussing the different methods of indirect blood pressure measurement the paper describes the fully automatic indirect blood pressure measuring apparatus, Type AVM-2 and AVM-4, development in Hungary. Experience gained using these instruments is reported and the requirements for this type of instrument outlined. Finally the paper discusses the most important characteristics of this equipment.


Hazards of cardiac pacing.

The implantation of a cardiac pacemaker is now widely accepted as the preferred method of therapy for heartblock, and is increasingly used for treatment of other cardiac abnormalities. Many thousands of pacemakers have been implanted since 1960. Some of the problems which arise from such implants are not urgent and are in the "low risk" category, whilst others require immediate remedial action. The hazards which are discussed are based on experience in Glasgow with over 500 pacemaker patients, over two thirds of whom are currently attending pacemaker clinics. If all pacemaker patients are to derive maximum benefit from their implants with minimum inconvenience and risk, there is a need for continued vigilance and better technology. There is also a need for retrieval of all pacemakers after death to confirm that death has not arisen from any of the technical faults which can place the lives of certain patients at great risk.


Venous occlusion plethysmography. Part 1: basic principles and applications.

A complete review of plethysmographic methods using the venous occlusion technique is given. All methods known to the author are covered, with comments on their applications. A comprehensive list of relevant literature concludes the review.


A semi-automatic instrument for estimating the differential leucocyte count.

A specially developed analogue processing unit was used with a Coulter cell counter and a pulse height analyser to determine the differential leucocyte count. The method is based upon a simplified analysis of the white cell volume distribution curve and the results agree well with those obtained by conventional methods.


A fully automatic device for compensating for artifacts in conventional catheter-manometer pressure recordings.

A device is described which detects the resonant artifacts in clinical cathetermanometer systems and automatically sets a notch filter so as to provide some measure of compensation. The equalised response characteristic does visibly improve transient response by removing resonant artifacts due to the uneven transfer function characteristic in these systems. Artifacts due to knocking of the catheter by the heart, external vibrations induced in the manometer, its mechanical support, or the catheter are reduced, but not eliminated. Nevertheless, the system described here has provided a solution to an important class of artifacts in conventional fluid filled catheter-manometer pressure recordings.


Origin of the nonexponentiality of the water proton spin relaxations in tissues.

An attempt to explain the nonexponential recovery of the water proton spin magnetization in tissues is presented. The origin of this effect is the nonhomogeneity of the material and the distribution of slow diffusion correlation times. This proposal is based on a dispersion study of the tissue water proton spin relaxation time in the rotating frame.


Permselectivity of the glomerular capillary wall to macromolecules. II. Experimental studies in rats using neutral dextran.

To determine the permselectivity characteristics of the glomerular capillary wall, known molecular size fractions of [3H]dextran, prepared by gel chromatography, were infused into normally hydrated Wistar rats, thus permitting simultaneous measurement of Bowman's space/plasma water (BS/P) and urine/plasma water (U/P) concentration ratios, along with glomerular pressures and flows. Since (BS/P)inulin = 1.01 +/- 0.01 SE(n = 34, radius = approximately 14 A) and since (BS/P)dextran/(BS/P)inulin equaled (U/P)dextran/(U/P)inulin for dextrans ranging in molecular radius from 21 to 35 A, these findings validate that dextrans are neither secreted nor reabsorbed. For dextran radii of 20, 24, 28, 32, 36, 40, and 44 A, (U/P)dextran/(U/P)inulin averaged 0.99, 0.92, 0.69, 0.42, 0.19, 0.06, and 0.01, respectively. In accord with theoretical predictions that these fractional dextran clearances should vary appreciably with changes in glomerular transcapillary pressures and flows, an increase in glomerular plasma flow rate, induced in these same rats by plasma volume expansion, resulted in a highly significant lowering of fractional clearance of all but the smallest and largest dextrans studied. These findings emphasize that fractional solute clearances alone are inadequate to describe the permselective properties of the glomerular capillary wall unless glomerular pressures and flows are also known. This sensitivity of fractional dextran clearance to changes in plasma flow indicates that dextrans are transported across the capillary not only by bulk flow but also to an important extent by diffusion.


Kinetic studies on insoluble cellulose-cellulase system.

Enzymatic hydrolysis of insoluble amorphous cellulose by Trichoderma viride cellulase was investigated in a batch reactor at several substrate concentrations and three enzyme levels. The reactions were carried out at 50 degrees C and pH 4.8. Enzyme was rapidly adsorbed onto solids on contact, then gradually returned to the liquid phase as the reaction proceeded. A kinetic model that considered the fast adsorption which was followed by the slow reaction, and subsequent product inhibition was developed to interpret the experimental observations. The resulting equation successfully correlated the data for up to 70% conversion. The methods for determining the kinetic parameters are discussed.


New mechanisms for the biosynthesis and metabolism of 2-keto-L-gulonic acid in bacteria.

L-Sorbose is oxidized to 2-keto-L-gulonic acid (KGA) via the following sequence of reactions which we call the "sorbosone pathway": L-sorbose in equilibrium L-sorbosone leads to KGA. The first step is reversible and is mediated by enzymes found in a soluble fraction obtained from Pseudomonas putida ATCC 21812. Although no cofactor requirements were found for the forward reaction, the reverse reaction clearly required NADH. Enzymes for this NADH-dependent synthesis of L-sorbose could be differentiated on the basis of molecular weights. The second step in the sorbosone pathway is catalyzed by a particulate enzyme found in extracts from P. putida and Gluconobacter melanogenus IFO 3293. The rate limiting reaction in the sorbosone pathway is the synthesis of L-sorbosone. In addition to P. putida, Klebsiella pneumoniae (ATCC 27858) and Serratia marcescens (ATCC 27857) also contain the enzymes which catalyze the reactions of the sorbosone pathway. Two of the bacteria studied, P. putida and G. melanogenus, also contain an enzyme involved in the further metabolism of KGA to L-idonic acid. This enzyme, referred to as KGA-reductase, is found in the soluble fraction of cell-free extracts and is dependent on NADH or NADPH.


Enzyme immobilized in a packed-bed reactor: kinetic parameters and mass transfer effects.

To describe axial dispersion, particle film mass transfer, intraparticle diffusion, and the chemical reaction of the substrate for enzymes immobilized in porous particles in packed columns, we have developed mathematical models for first- and zero-order limits of Michaelis-Menten kinetics. Steady-state solutions were derived for both long and short column boundary conditions and for plug flow. Theory was compared to experiments by hydrolysis of sucrose catalyzed by invertase bound to porous glass particles. Steady-state conversions were measured for a range of flow rates. Pulse response experiments with inert packing were used to determine values of bed void fraction and particle porosity.


A model for diauxic growth.

A model is developed to predict batch and continuous culture behavior of fermentations on two different carbon and energy sources. The basic assumption of the model is that the permease for the favored substrate is constitutive, whereas the premease for the second substrate is subject to induction and catabolite repression. Simulations of the model show features of diauxic growth described in the literature.


The total containment of a batch-type zonal centrifuge.

A batch-type zonal centrifuge has been modified and totally contained for use with biologically hazardous materials. A sealed cabinet encloses the centrifuge and the ancilliary equipment. It is operated with a flow of filtered air when the zonal system is on, decontaminated with ethylene oxide, and maintained at a negative pressure throughout. The centrifuge subsystems can be drained, flushed, and decontaminated with ethylene oxide before an engineer services the machine. The sample handling system within the cabinet is remotely controlled.


Production of plant virus inhibitor by Phytolacca americana suspension culture.

The inhibitory activity of tobacco mosaic virus (TMV) infection was assayed with the extracts of various callus tissues derived from the intact plants. Phytolacca americana callus was selected as a producer of the virus inhibitor and its cultural conditions in suspension were examined for cell growth and the inhibitor production. A modified liquid medium containing twofold concentrations of all components in that of Murashige and Skoog plus2,4-D (1.0 mg/liter) and sucrose (6%), but without any vitamins and glycine was chosen for production of higher levels of the inhibitor. TMV infections in tobacco, bean, and tomato plants were markedly inhibited by the introduction of the disrupted whole broth of suspension cultured P. americana.


[Spontaneous chromosome aberrations in the oogenesis of laboratory rats].

Cytological preparations were made by Tarkovsky's method from 2335 rat oocytes obtained after an induced superodulation. The chromosomes could be counted exactly in 861 oocytes. In 797 oocytes (92.7%) euploidy (metaphase II with 21 chromosomes) and in 64 oocytes (7.5%) aneuploidy was found. 60 oocytes were hypoploid, but only 4 oocytes (0.4%) were hyperploid (with 22 chromosomes). Hypoploidy can often be due to the presence of artefacts. Probably the rate of spontaneous aneuploidy in rat oogenesis is about 0.8%, this being significantly lower than the rate of spontaneous aneuploidy in mice oogenesis.


[Comparative study of the ultrastructure of immune and normal phytohemagglutinin-treated lymphocytes].

Immune lymphocytes sorbed on the surface of the target cells were characterized during the period of the first three hours of combined incubation by the presence of the electron-dense matrix, abundance of mitochondria and lipids; small lymphocytes had disseminated ribosome organized into polysomes in the medium lymphocytes forming individual cysterns of the granular endoplasmic reticulum in the large lymphocytes, this indicating active protein synthesis by these cells. There were also revealed cells of plasmatic type. Cells incubated with the PHA for one hour represented a homogenous population of small lymphocytes of the same size as the clear cytoplasm containing free ribosomes and individual mitochondria. The proportion of the medium lymphocytes and the blasts increased with increase of the incubation period. These are cells with the clear cytoplasm freely disseminated polyribosomes in which no developed granular endoplasmic reticulum was sometimes revealed. The presence of two types of cells whose ultrastructure reflected their functional characteristics is discussed.


[Histomorphological study of wound regeneration in animals irradiated for a long time with low-intensity microwaves].

Experimental study on 80 guinea pigs showed that in the animals exposed for a long time to the action of microwabes of low intensity the linear skin wounds healed by primary intension much more rapidly than in the non-irradiated animals. The  postoperative scar was much more reliable in the irradiated animals. On the third day the irradiated animals were found to have a more intensive regeneration of the epithelium in the inflicted wound, and an intensive development of the granular tissue in the inferior portions. Later, an aceelerated synthesis of proteins, including that of collagen in the wound was observed; there was also a marked process of maturation of the granular tissue and formation of the intercellular substance. On the 7th-9th days fresh connective tissue (rich in fibroblasts with young fuchsinophilous collagen fibers) replaced the granular tissue; it was more mature than in the non-irradiated animals.


[Mechanism of the discontinuance of work as a consequence of fatigue according to the change in the electromyogram in a hypnotic state].

A study was made of the changes in the bioelectrical activity of the muscles in the course of local static work up to "refusal" under the usual conditions and under condition of inhibition of the program-control function of the cortex (during the somnambulistic stage of hypnosis). Experimental results indicated that during the hypnotic state the time of persistence of the static effort doubled in comparison with control; the bioelectrical activity increased 1 1/2-2 times, and in individual experiments--3--4 times. In the light of the data obtained the mechanism of formation of "refusal" to work could be viewed as an active arrest of the activity of the central formations realizing the program-control functions.


[Characteristics of the synaptic structure and of the parameters of the electrically excited muscle fiber membrane of fetal and newborn rabbits].

In intensification of the motor adaptive reactions of the fetus under conditions of a not marked inhibition of the gestation dominant there occurred an acceleration of development of the synaptic structure and of the corresponding characteristics of the muscle fibers. In depression of the motor reactions of the fetus under conditions of a sharp inhibition of the gestation dominant there occurred a retardation of the development of the synaptic structure, of the electrophysiological characteristics and of the transverse striations of the muscle fibers, this being regarded as the result of deficiency of the neurotrophic influences of the skeletal muscles in the physiologically immature fetuses and neonates.


[Electrical activity of the motor units of the muscles in blood supply disorders of the latter].

Electrical activity of the motor units in the muscles (m. gastrocnemius and m. extensor hallucis brevis) in normal humans and in the patients with impaired peripheral circulation in the lower limbs was studied with the needle concentric electrodes. A reduction in the muscle action potentials under conditions of their circulation impairment was revealed; this pointed to the myogenic origin of alterations in the skeletal muscles due to the incompetence of their blood circulation.


[Canges in the monoamine content in the cat brain in a unilateral lesion of the cerebral cortex].

A spectrofluorometric study of the changes in serotonin and noradrenalin content was carried out in the cortex of large hemispheres, the hypothalamus and the midbrain on the 5th-6th day after creation of a pathological focus in the area of the occipital portion of the cortex in 12 cats. Diffuse changes in the bioelectrical activity of the brain were revealed on the EEG at this period: there appeared peak-like variations and slow waves of increased amplitude. There was noted a marked decrease in serotonin content in the cortex of the large hemispheres with the prevalance of an effect in the area directly adhering to the focus of affection. A tendency to reduction in serotonin level was revealed in the hypothalamus and the midbrain. The content of noradrenalin in the mentioned structures of the brain showed no significant change. The significance of the serotoninergic structures of the brain in the mechanisms participating in the restoration of the functional condition of the brain after its experimental injury is discussed.


[Effect of a lesion of the hypothalamic nuclei on the morphofunctional state of the hypothalamo-hypophyseal system and the development of experimental atherosclerosis].

Injury of individual nuclei of the anterior and the middle portions of the hypothalamus in rabbits by electrocoagulation through the preliminarily implanted electrodes was accompanied by the change in the morpho-functional condition of the hypothalamo-hypophysial neurosecretory system (HHNS). The nearer the focus of injury to the region of the supraoptic nuclei -- the greater the functional activity of the HHNS. In combining the injuries of individual hypothalamic nuclei with the atherogenic diet there occurred marked morpho-functional changes both in the HHNS and in the adrenal glands; as to animals with experimental atherosclerosis, it acquired under these conditions a more severe form than in the animals on the atherogenic diet alone. Results of investigations pointed to the presence of a close association of the genesis of the atherosclerotic process with the neurogenic factors.


[Disorder of gamma-motor neuronal activity in experimental thyrotoxicosis].

The activity of gamma-motor neurons was studied in the anesthetized rats following per os administration of thyroidin for 3 weeks. In experimental thyrotoxicosis against the backgrounds of an increased amount of mute filaments isolated from the stem of the n. gastrocnemius there was an increase in the frequency of discharge of the flexors and extensors of the gamma-motor neurons. A high frequency not peculiar to that of intact animals was recorded in the flexors of the gamma-motor neurons of the animals receiving thyroidin.


[Participation of the posterior hypothalamus in the activity of the ascending activating system].

In chronic experiments on cats with premezencaphalic section of the brain stem electrica stimulation of the posterior hypothalamus caused desynchronization of the electrical activity of the neocortex. After the isolated injury of the posterior hypothalamus a moderate electrical stimulation of the medical part of the midbrain reticular formation failed to cause any pronounced activation of the neocortex. The results obtained indicated an important role of the posterior hypothalamus in the function of the ascending activating system.


[Thyroxine depression of compensatory hypertrophy of the thyroid gland in rats of different ages].

It was shown on hemithyroidectomized male rats (2--2.5, 8--10 and 14--16--month-old) that with the advance of age there occurred an increase in the inhibitory effect of the same (as per 100 g of body weight) dose of the exogenous thyroxine on the thyroid compensatory hypertrophy. It is supposed that the threshold of hypothalamo-pituitary-thyroid system to homeostatic inhibition decreased with ageing.


[Acute cell death in various sections of the gastrointestinal tract in DNA synthesis inhibition].

Injection of hydroxyurea induced degeneration of almost all the cells synthesizing DNA in the crypts of the jejunum and of only 10% of such cells in the epithelium of the glandular stomach in mouse. Inhibition of the DNA synthesis by hydroxyurea was complete in both tissues. Thus, the cells of the glandular stomach withstood inhibition of the DNA synthesis without and degeneration.


[Changes in the liver lysosomes of the rat in chronic toxic hepatitis].

A study was made of permeability of the lysosome membranes and subcellular distribution of acid hydrolases in chronic hepatitis caused by CCl4 inhalation and during the restoration of the liver after injury. No normalization of the indices under study occurred during the period of up to 14 days after the last CCl4 inhalation: changes in the stability of the lysosome membran persisted and redistribution of acid hydrolases was noted. This redistribution was associated with both the processes of injury and restoration of the liver.


[Phospholipids and thromboplastins in various sections of the brain normally and in excitation states].

The level of the neutral and acid phospholipids and thromboplastic activity of various portions of the rabbit brain were studied under normal conditions and following adrenaline stimulation. The level of total phospholipids, neutral phospholipids, and the ratio of neutral to acid phospholipids, thromboplastic activity and its increase following incubation of homogenates of the brain tissue of normal and adrenaline-treated animals were found to be distributed in the following descending order: the medulla oblongata, cerebellum, cerebral hemispheres. Adrenaline decreased the thromboplastic activity and induced changes in the neutral and acid phospholipid levels. The role of phospholipids in the biosynthesis of various components of the blood clotting and anticoagulant systems are discussed.


[Effect of psychotropic substances on conditioned reflexes in cats after emotional excitation].

Emotional rage and fear were found to destroy the differential inhibition and the short-term memory in cats. Stelazine, haloperidol, amitriptyline, imizine, chlordiazepoxide, diazepan and benactyzine prevented these disturbances. Chlorpromazine, as well as stelazine and haloperidol in high doses, enhanced these disturbances. The tranquillizers and the antidepressants normalized the higher nervous activity at a greater dose range than neuroleptics and were more preferable for the elimination of the negative consequences of the strong emotional reactions.


[Effect of some adrenergic substances on the cumulative effect of strophanthin].

Experiments were conducted on cats; a study was made of the effect of pharmacological block and stimulation of the adrenergic innervation on the toxicity and the cumulative effect of strophanthine. It was found that anapryline premedication and a preliminary reserpinization increased the strophanthine tolerance and reduced its cumulative effect. Isadrine caused a sharp elevation of the sensitivity to cardiac glycoside, but no cumulation was present in this case.


[Effect of prothixen and related compounds on serotonin absorption by human thrombocytes].

Distribution of preparations in the order of reduction of the inhibitory influence on serotonin (ST) absorption by platelets corresponded to the distribution of the preparations, by decrease in the thymoanaleptic action: chlorimipramine greater than imipramine greater than amitryptiline desimpramine-nortyptyline-chlorprotixen greater than chlorpromaxine greater than norprotixen greater than protixen-propazine. A change in the influence of the preparation on the ST absorption by platelets caused by the administration into the structure of the chlorine atom compound or by demethylation of the preparation was largely determined by the chemical structure of the initial compound.


[DNA and antibodies to DNA in Aleutian mink disease].

Free DNA and various types of antibodies to DNA were determined in the blood serum and plasma of minks which contracted Aleutian disease (AD) spontaneously and of minks experimentally infected with this disease. Healthy minks and other animals served as controls. It was found that a higher incidence of antibodies to DNA of the 2nd and 3rd types in high titres (1: 80-1: 2560) was characteristic of the experimental group of animals. Besides, a free polymeric DNA was more frequently revealed in the experimental group of animals.


[State of the hypothalamo-hypophyseal neurosecretory system of rabbits in anaphylactic shock].

With the aid of morphometric and histochemical methods a study was made of the hypothalamo-hypophyseal neurosecretory system of rabbits in anaphylactic shock. The following occurred in rabbits which survived the shock: an enlargement of the perikarions and reduction in the size of the nuclei and nucleoli of the neurosecretory cells; the content of the neurosecretory substance was increased in the whole neurosecretory system. In rabbits which perished from shock the nuclei and the nucleoli of the neurosecretory cells diminished to a lesser extent, perikarion measurements remained unchanged and the content of the neurosecretory substance in the posterior lobe of the hypophysis fell. Thus, in the animals which survived the shock the processes of synthesis of the neurohormones by the neurosecretory cells were sharply activated, but the secretion of the neurohormones from the posterior lobe of the hypophysis was inhibited; in animals which perished from shock the activation of the hormone formation in the neurosecretory cells was less pronounced, but the processes of the secretion of the neurohormones from the posterior lobe were apparently intensified.


[Change in the RNA content in the rat endometrium under the action of estrogen-megestrol and neurotropic substances].

The effect of the hormone-like estrogen-progestagen preparation megestranol and of megestranol-spasmolytin combination on the activity of metabolic processes in the uterine mucous membrane was studied in experiments on rats. Results of cytochemical studies showed megestranol and megestranol-spasmolytin combination to change  the metabolic activity of the uterine mucous membrane resulting in a decrease in the RNA content in the epithelial cells of the endometrial glands, thereby creating conditions preventing normal implantation and development of the fertilized ovum.


Biomechanics of a lymphatic vessel.

The principles of mechanics and the current notions of lymphatic physiology are integrated into a simple mathematical model of a lymphatic vessel which establishes a theoretical base for lymph propulsion in the lymphatic system. The model specifically considers the active and passive contractilities of the lymphatics. The model is simulated on a digital computer. The pressure and flow patterns derived from the model are consistent with the currently available experimental data.


Calcium flux and binding in the aortic smooth muscle from the spontaneously hypertensive rat.

There was no significant difference in the tissue calcium content between spontaneously hypertensive rat (SHR) and normotensive rat aortae. 45Ca uptake was significantly greater, whereas 45Ca influx was significantly less in SHR than in control aortae. There was no difference in 45Ca efflux in SHR and control tissues. 45Ca influx in both SHR and control tissues was increased by potassium, not increased by norepinephrine and inhibited by Co++, Mn++ and La+++ (all 0.5 mM). Both SHR and control aortae were equally inhibited by Mn++ and Co++ (0.1 mM). There was no difference in the 45Ca uptake by microsome fraction from both SHR and control tissue. These data indicate some differences in the translocation of Ca++ at the cellular level in SHR and control aortae.


Comparison of the relaxing effect of dopamine with that of adenosine, isoproterenol and acetylcholine in isolated canine coronary arteries.

Isolated canine coronary arteries were contracted with prostaglandin F2a and the relaxing effects of dopamine, adenosine, isoproterenol and acetylcholine were compared. Relaxation induced by dopamine in phenoxybenzamine-treated arteries was not significantly influenced by propranolol and atropine in concentrations sufficient to shift dose-respone curves of isoproterenol and acetylcholine, respectively, to the right. Dose-response curves of isoproterenol were shifted significantly to the left by 2 x 10(-5) M aminophylline. In contrast, the relaxing effect of adenosine was significantly attenuated by aminophylline (5 x 10(-6)-10(-4) M) in a dose-dependent manner. Kinetic analysis showed that aminophylline competitively antagonized the effect of adenosine, and the pA2 was 5.57. At these concentrations, aminophylline did not alter the relaxing action of dopamine and acetylcholine. It may be concluded that dopamine produces relaxation at a different site and with a different mechanism of action from those of isoproterenol, the effect of the latter being presumably mediated by cellular cyclic AMP, and that dopamine also does not share the site of action with adenosine and acetylcholine. It appears that receptive sites specific for adenosine are present in canine coronary arteries.


Isoenzymes of lactate dehydrogenase in varicose veins.

The activity of lactate dehydrogenase and fractions of this enzyme has been estimated in human large saphenous veins. Typical varicosities were compared in composition with normal veins from the same patients. The total LDH activity was significantly decreased in typical varicosities. Varicose veins further differed from macroscopically normal veins by a lower content of aerobic fractions of LDH and a higher content of anaerobic fractions. These results suggest that there is a disturbance in metabolism of the smooth muscle of the venous wall in varicosities which would make the diseased wall more dependent on anaerobic glycolysis than normal tissue.


Interaction of mono- and divalent metallic cations and of indomethacin on the membrane potential of vascular endothelial cells in vitro.

1 Endothelial cells depolarized progressively when heated for 5 h at 45 degrees C in the presence of calcium (1 mM), cupric (0.08 mM) or ferrous (0.04mM) ions. In the absence of these ions, heating caused only slight depolarization. Higher concentrations of these ions caused depolarization even at normal body temperature (37 degrees C). 2 Cuprous and potassium ions, although producing depolarization at 37 degrees C, failed to augment the depolarization due to heating to 45 degrees C. 3 Hydrogen peroxide caused depolarization which was potentiated by the presence of calcium, cupric or ferrous ions, but not by the presence of cuprous or potassium ions. 4 Indomethacin (0.25 mM) reduced the depolarization caused by calcium, cupric or ferrous ions at 37 degrees C and also reduced the potentiation of heat-induced and hydrogen peroxide-induced depolarization which these divalent metallic cations produced. However, indomethacin failed to modify the depolarization caused by cuprous or potassium ions.


Mechanism of mechanical inhibition of smooth muscle by ouabain.

1 Ouabain (10 mug/ml) caused an initial increase followed by a decrease in tension in guinea-pig taenia coli bathed in normal sodium and potassium containing medium. 2 The excitatory effect of ouabain was prevented by the elevation of extracellular potassium while the inhibitory effect was abolished in the absence of sodium in the bathing medium. 3 In the presence of sodium, the inhibitory effect of ouabain disappeared when the drug was washed out, but in the presence of lithium (which is not extruded by the Na-K pump) the inhibition was not abolished. 4 The inhibitory effect of ouabain was accompanied by an increase in tissue Na and a decrease in tissue K concentration. The increase in intracellular [45Ca] which occurred when extracellular [k] was varied, was also reduced by ouabain. 5 It is concluded that a high intracellular level of sodium inhibits contractions in visceral smooth muscle probably by a mechanism involving decreased Ca influx.


Forecasting the antimalarial activities of arylamidinoureas from their measured physicochemical properties.

1 The octanol : water partition coefficient (PC), protein binding coefficients to albumin (Ba) and haemoglobin (Bh), proton magnetic resonance (PMR) chemical shifts and pKa of 8 arylamidinoureas have been measured. 2 There were statistically significant correlations for 7 of the 8 compounds between the predicted lipophilicity parameter eta and log PC, Ba and Bh, and also between Hammett's electronic parameter sigma and the PMR and pKa observations. 3 3-Chloro,4-nitrophenylamidinourea showed a larger deviation from these correlations than any other compound. Geometric calculations based on the covalent radii and bond angles of the molecule suggested that the neighbouring chloro and nitro substituents were interacting sterically. 4 Molecular orbital calculations and the observed ultra-violet spectrum provided further evidence for such an interaction, and suggested that the nitro group is twisted out of the plane of the benzene ring in this molecule. 5 Such steric interactions can introduce an additional source of error when attempts are made to correlate the biological and predicted physicochemical properties of compounds. 6 Generalized parameters such as eta and sigma cannot be used with confidence to predict the properties of compounds in which such steric interactions occur.


Desensitization in the innervated and in the chronically denervated soleus muscle of the mouse.

1 A study was made of desensitization in chronically denervated and in normally innervated mouse soleus muscles. 2 Very high concentrations of acetylcholine produced small contractions of the innervated muscles; these were reduced in size when the addition was repeated 1 min after wash-out. 3 Desensitization in innervated muscles was receptor specific: contractions in response to KCl and caffeine were not reduced following acetylcholine, nor did KCl produce desensitization. 4 In chronically denervated muscles non-specific desensitization was observed if acetylcholine was added in the presence of low concentrations of acetylcholine or carbachol. Contractions to KCl but not to caffeine were reduced. KCl produced a similar kind of desensitization. 5 After washing out moderate or supramaximal concentrations from the chronically denervated muscle no desensitization was observed. However, 1 min after washout of very high concentrations the muscle was non-specifically desensitized. 6 It is concluded that relatively high concentrations of acetylcholine are required to produce specific desensitization in the soleus muscle. Chronically denervated muscles, being supersensitive, show non-specific loss of sensitivity with concentrations of acetylcholine too low to produce specific desensitization.


A comparison of the effect of mescaline on activity and emotional defaecation in seven strains of mice.

1 Mescaline hemi-sulphate (35 mg/kg body weight) was injected intraperitoneally into male mice (Mus musculus) from seven genetically diverse laboratory strains. 2 The effect of mescaline was found by comparison of the emotional defaecation and open field activity of mice after mescaline injection with the performance of the same mice after a subsequent saline (0.9% w/v NaCl solution) control injection. 3 In strains A2G, C3H/He, C57BR/cd, CBA/Cam and F/St, mescaline inhibited emotional defaecation and stimulated open field activity. These effects did not occur in strains 1CFW and Schneider. 4 A positive relationship was found between the degree of emotional defaecation characteristic of each strain in the saline control experiment and the inhibitory effect of mescaline on emotional defaecation. 5 Pre-treatment of mice with tranylcypromine (20 mg/kg body weight, i.p.) had no effect on emotional defaecation or on its inhibition by mescaline.


The penetration of dapsone, rifampicin, isoniazid and pyrazinamide into peripheral nerves.

1 Dapsone, rifampicin, isoniazid and pyrazinamide were shown to penetrate readily into the sciatic nerves of the dog and sheep. 2 These findings suggest that the continued persistence of viable drug-sensitive leprosy bacilli in the peripheral nerves of patients treated for long periods with either dapsone or rifampicin is not due to inadequate intraneural drug penetration.


Meiosis: a prostaglandin response that is not inhibited by aspirin.

Antidromic stimulation of the sensory nerve to the rabbit eye produces pupillary meiosis, supposedly by release of prostaglandins into the aqueous humour. The analogy between this phenomenon and neurogenic inflammation is drawn. It is shown that aspirin and indomethacin, known blockers of prostaglandin synthesis and release, fail to block the meiosis thus produced.


Effects of iprindole on responses of single cortical and caudate neurones to monoamines and acetylcholine.

1 The technique of microelectrophoresis was used to study the effects of iprindole on single neurones in the cerebral cortex and caudate nucleus of the rat. 2 Iprindole, when applied for a brief period, did not affect the firing rate of the vast majority of neurones tested. 3 Both potentiation and antagonism of neuronal responses to noradrenaline, dopamine, and 5-hydroxytryptamine could be observed after a brief application of iprindole. Potentiation and antagonism often occurred after the same application of iprindole, antagonism always preceding potentiation. 4 Responses to acetylcholine were affected by iprindole similarly: both potentiation and antagonism of the responses could be observed. 5 Responses to glutamate were not affected by iprindole. 6 It is concluded that the potentiation of responses to monoamines by iprindole cannot be explained on the basis of uptake blockade; this potentiation may be due to the blockade of masked receptors on the post-synaptic cell. 7. It is suggested that the common pharmacological action of the tricyclic antidepressants may be the ability to block both monoamine and acetylcholine receptors in the brain.


The action of 5-hydroxytryptamine on chemoreceptor discharges of the cat's carotid body.

1 Chemoreceptor discharges were recorded in vivo from fine filaments of the carotid sinus nerve containing a single or several active units; their frequency was used as an index of receptor activity. The effects of 5-hydroxytryptamine (5-HT) on chemoreceptors were studied in 26 adult cats. At times, sinus baroreceptor discharges were recorded from the carotid nerve and the effect of 5-HT on the discharges was examined. 2 Intra-carotid injections of 5-HT (2-20 mug) induced a sharp and brief increase in chemoreceptor discharges, followed by depression or block which lasted for several seconds. Repeated injections at short intervals, and a small dose after a large dose of 5-HT resulted in depressed or blocked response to 5-HT. 3 5-HT in high doses (10-20 mug, i.a.) slightly depressed the chemoreceptor discharges induced by either acetylcholine (ACh) or NaCN, when these substances were applied within 20 s after 5-HT. 5-HT (5-20 mug, i.a.) applied during asphyxia induced a further increase in chemoreceptor discharges, soon followed by block of the discharges lasting for several seconds. 4 Atropine or hexamethonium in high doses did not change the chemoreceptor response to 5-HT, while that to ACh was markedly depressed. 5 (+)-Lysergic diethylamide (LSD), methysergide or gramine did not alter the response to 5-HT, while LSD in low doses produced a marked increase in chemoreceptor discharges. 6 Acute and chronic treatment with reserpine (5-10 mg/kg, i.v.) of the animals did not change the sensitivity and the reactivity of the chemoreceptor to ACh and NaCN, while the chemoreceptor response to 5-HT was augmented, indicating an increase in the sensitivity of chemoreceptors to 5-HT. 7 5-HT in small doses (2-10 mug, i.a.) induced a marked increase in sinus baroreceptor discharges; subsequently discharges were depressed or blocked for several seconds. 8 The results are discussed in relation to possible mechanism of action of 5-HT on the chemoreceptors. It is concluded that the exogenous 5-HT probably acts directly on the chemosensory nerve endings and depolarizes them, but 5-HT contained in the carotid body does not play a significant role in the generation of chemoreceptor discharges.


Pressor response induced by local anaesthetics perfused through the cerebral ventricles of dogs.

1 The antihistamines mepyramine and halopyramine which have local anesthetic properties, produced a rise in arterial blood pressure followed by a fall, similar to that seen with procaine, when perfused in a 10 mg/ml solution from the lateral ventricle to the cisterna magna in dogs. 2 The pressor response produced by procaine perfused through the cerebral ventricle is due to an action on structures situated in the caudal half of the floor of the fourth ventricle because a pressor response was obtained when a few microlitres of a 50 mg/ml solution of procaine were applied to a small area of the exposed floor of the fourth ventricle in a region 2 to 4 mm rostral to obex, and after cauterization of this area procaine perfused through the cerebral ventricles no longer raised arterial blood pressure. 3 Bilateral denervation of the carotid sinus did not affect the pressor response obtained with procaine perfused through the cerebral ventricles. 4 The pressor response to procaine is mediated through the sympathetic nervous system. It results partly from an increased adrenaline discharge from the adrenal glands and partly from increased sympathetic vasomotor tone, because the response is abolished or attenuated after removal of the adrenal glands and intravenous injections of hexamethonium and phentolamine.