Homologous dura mater used to close thoracic wall and diaphragmatic defects.

We have reported the successful use of homologous dura mater preserved in glycerin at room temperature to repair large defects of the thoracic wall or diaphragm in five patients. The surgical technic involved the use of autologous bone grafts in order to stabilize the thoracic cage in one case, but in the other four the dural blade was sufficient. The postoperative course was uneventful regarding the structure and function of the dural implant in each case.


Mental health intervention with children and adolescents with end-stage renal disease.

The increasing number of pediatric patients with end-stage renal disease who undergo dialysis and transplantation have necessitated the development of psychological interventions to lessen the emotional impact of these procedures. This report describes the dilemmas involved in mental health interventions and consultation in a treatment program for end-stage renal disease. Case illustrations of a young child's severe anxiety reaction to dialysis, an adolescent's depression, and a family's withdarwal document the varied patterns of adaptation to treatment for renal failure. Psychotherapeutic approaches are presented to illustrate the flexible use of a number of treatment modalities including brief crisis-oriented intervention which emphasized the patient's cognitive mastery of procedures. The development of viable mechanisms of professional collaboration improves the quality of patient adaptation by lessening the fragmentation of care and problems of interdisciplinary communication often associated with the medical care of children and adolescents with end-stage renal failure.


[Internal treatment of psoriasis--a review].

Psoriasis has been treated systemically through most of this century, originally with arsenics, which have been given up due to their carcinogenic effect. Later glucocorticoids were used, but were then abandoned on account of their high frequency of side effects and the appearance of the rebound phenomenon. Cytostatic drugs have been employed for nearly 25 years. Methotrexate is the most common preparation. Methotrexate requires a normal liver-, kidney- and bone marrow function. Pregnancy is an absolute contraindication. Photochemotherapy with oral methoxalen and long wave ultraviolet light is a new treatment which seems promising. This regime, however, is still at a stage of clinical trial.


Problems with beaded fluorescence pattern in FTA-ABS test.

The significance of false-positive FTA-ABS fluorescence in connective tissue diseases and other clinical conditions was evaluated by studying the serum from several groups of patients. In 12% of 67 patients without syphilis, serum with an antinuclear antibody (ANA) titer of 1:32 or greater gave low intensity FTA-ABS test fluorescence. In 20% of 150, patients (2.7% with a history of syphilis), serum with rheumatoid factor (RF) titers of 1:640 or greater demonstrated some reactivity. Only 1.3% of 75 donors of normal blood showed low-grade FTA-ABS fluorescence. In 385 patients with diagnostic problems, 2.1% of the serum demonstrated the beaded pattern. Patterns varied, depending on the treponemal antigen preparation and the duration of serum storage. Also, multiple specimens from the same patient produced different patterns. Furthermore, the beaded pattern could be demonstrated in patients with a history of syphilis, with other medical disorders, and in apparently normal persons.


The microhemagglutination assay for Treponema pallidum antibodies (MHA-TP), a new treponemal test for syphilis: where does it fit?

The status of a new treponemal test, the Microhemagglutination Assay for Treponema pallidum Antibodies (MHA-TP) is reviewed and compared with regard to its sensitivity, specificity, and current clinical application to the VDRL slide test, the most widely used non-treponemal test, and to the manual FTA-ABS test, the standard treponemal test. At present, the MHA-TP test seems to combine the simplicity and lower cost of nontreponemal tests and the sensitivity and specificity of treponemal tests, and thus enjoys features of both a screening and verification procedure. However, additional clinical experience with the test is needed before its role in the serologic diagnosis of syphilis can be conclusively determined.


Biopharmacology of syphilotherapy.

Data collected from experimental rabbit syphilis and from in vitro studies with nonpathogenic treponemes can be extended only with great caution to human syphilis. The following tentative conclusions may be drawn: penicillin acts on Treponema pallidum by interfering with cell wall synthesis. Concentrations of penicillin greater than 0.1 mug/ml do not have increased treponemicidal effect. Regimens producing penicillinemia for at least 8 days are considerably more efficient than treatment yielding high peak serum levels of brief duration. Treponemal residence in antibiotic-protected sites increases the need for long duration therapy. Other antibiotics are less effective than penicillin, and patterns of antibiotic interaction against treponemes do not match those seen with other bacteria.


The blood supply of the mammalian adrenal medulla: a comparative study.

Adrenal medullary arteries have been followed from their origins in the capsular or subcapsular plexus to the medullary plexus in the mouse, rat, hamster, cat, guinea-pig, rabbit and bovine. Adrenal medullary arteries have a zonal distribution to the medullary capillary plexus and the number of arteries present in species variable and proportional to the size of the medulla. Cortical veins drain through distinct venous channels between groups of chromaffin cells, and may run adjacent to either adrenaline-storing (A) or noradrenaline-storing (NA) cells. In the normal unstimulated gland both A and NA cells lie adjacent to capillaries of the medullary plexus which derive their blood supply from adrenal medullary arteries. In the normal unstimulated gland no evidence of selective supply of arterial or venous blood to either A or NA cells has been obtained.


Light microscopic identification of immature glial cells in semithin sections of the developing mouse corpus callosum.

Four distinct types of glial cell were recognized in the corpus callosum of young postnatal mice: the early glioblast; the small glioblast; the large glioblast; and the young astrocyte. As well as these, mature microglia could be recognized from birth. In semithin, toluidine blue stained sections early glioblasts had large, fair to moderately stained nuclei, and a thin rim of pale cytoplasm; small glioblasts had small, dark nuclei and a rim of darkly stained cytoplasm; large glioblasts had moderately unevenly stained nuclei and a thin rim of moderately stained cytoplasm; and young astrocytes had fairly small nuclei, moderately stained cytoplasm, and one or more processes, which could usually be seen extending for 5 mum or more from the perikaryon. Differential glial counts using the criteria described above, in conjunction with electron microscopic analysis, suggested that early glioblasts gave rise to small glioblasts and large glioblasts; that small glioblasts gave rise directly to astrocytes, large glioblasts, oligodendrocytes and possibly microglia; that large glioblasts formed oligodendrocytes only, and might be immature light oligodendrocytes; and that part of the microglial population might arise from vascular pericytes.


Effect of the leucomycin-like macrolide antibiotic turimycin on ribosomal peptidyltransferase from Eschericha coli.

The relationship between the effect of different turimycin components on ribosomal peptidyltransferase of E. coli, antimicrobial activity and chemical structure were studied. Inhibition of peptidyltransferase as well as antimicrobial activity increased with the length of the aliphatic side chain in 4''-position of mycarose and decreased with acylation in 3-position of the lactone ring. Inhibition of peptidyltransferase is paralleled by inhibition of acceptor substrate binding.


O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Further purification and characterization as a pyridoxal enzyme.

O-Acetylserine-O-acetylhomoserine sulfhydrylase [EC class 4.2.99], catalyzing the sulfhydrylation of both O-acetyl-L-serine (OAS) and O-acetyl-L-homoserine (OAH) (O-acetyl-L-serine(O-acetyl-L-homoserine) + H2S leads to L-cysteine (L-homocysteine) + acetate), was extracted and purified from bakers' yeast by an improved method. The purified enzyme was shown to be homogeneous on polyacrylamide gel electrophoresis both in the absence and presence of sodium dodecylsulfate and by ultracentrifugal analysis. The apo-enzyme was protected by pyridoxal phosphate (PALP) from inactivation by heat, urea, and trypsin [EC 3.4.21.4], suggesting that the binding of PALP to the apo-enzyme rendered the conformation of the protein more stable. The holo-enzyme showed absorption peaks at 420 and 330 nm due to bound PALP, in addition to a peak at 280 nm. Upon reduction with borohydride, the 420-nm peak disappeared and an increase in the 330-nm peak occurred concomitant with loss of the catalytic activity. Lysine appeared to be the pyridoxal binding site, based on identification of pyridoxyl-lysine in the hydrolyzate of the holo-enzyme. It was shown by both spectral and chemical determinations that 4 moles of PALP could bind to 200,000 g of apo-protein. The apo-enzyme showed a lower association constant with PALP than some other enzymes. Pyridoxal inhibited the activity competitively with respect to PALP. Based on these findings, it appears that the reaction mechanism of this enzyme is similar to those of other pyridoxal enzymes.


O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Subunit structure.

The molecular weight of O-acetylserine (OAS)-O-acetylhomoserine (OAH) sulfhydrylase purified from yeast was estimated to be about 200,000 by Sephadex G-200 gel chromatography in various buffers. The S20, w value of this protein was determined to be about 9.0 by sucrose density gradient centrifugation. The calculated molecular weight based on this value was similar to that estimated by gel chromatography. Treatment with 1% sodium dodesylsulfate (SDS) or 6 M urea dissociated the enzyme into 4 subunits; these had a molecular weight estimated to be 51,000 by SDS-poly-acrylamide gel electrophoresis and to be 57,000 by Sephadex G-100 gel chromatography in the presence of 6 M urea and 0.5% beta-mercaptoethanol. The 4 subunits appeared to be identical, based on the symmetric subunit elution pattern from a Sephadex column, a single peptide band on SDS-polyacrylamide gel, and the detection of histidine as the sole N-terminal amino acid in the native enzyme. Since dissociation into the subunits occurred without the use of reducing agents, the association of the subunits seems to require no disulfide linkage. One mole of the subunit contained one mole of sulfhydryl group which appeared to be buried inside the molecule. Partial restoration of the catalytic activity was observed when the urea-denatured enzyme was dialyzed to remove urea, especially in the presence of reducing agents such as dithiothreitol. The urea-denatured enzyme showed a tendency in the absence of reducing agents to form a subunit dimer linked by a disulfide bond between the cystine residues exposed by denaturation. The amino acid composition of the enzyme was determined; it contained one half-cystine residue per subunit, and the content of acidic residues was much higher than that of basic residues. Based on these findings, the subunit structure of the enzyme is discussed.


Escherichia coli membrane D-lactate dehydrogenase. Isolation of the enzyme in aggregated from and its activation by Triton X-100 and phospholipids.

D-Lactate dehydrogenase was obtained in an aggregated form consisting of 2 to 3 molecules of the monomer enzyme after removal of most Triton X-100 from the preparation as described previously (1). The aggregate dissociated reversibly to the monomeric form after addition of 0.06% or 1.0% Triton X-100. Formation of these aggregates was confirmed by the finding that the enzyme activity was only partially sensitive to specific antibody. The specific activity of the aggregated enzyme was one-third that of the enzyme with Triton X-100 and it increased approximately 5-fold on addition of phospholipids or cardiolipin of Escherichia coli and lecithin from egg yolk. Both the monomer and micelle forms of Triton X-100 caused activation of the enzyme. The activity of the aggregates after preincubation with Triton X-100 or phospholipids was completely inhibited by specific antibody. The difference in the properties of the aggregated enzyme after preincubation with Triton X-100 and with phospholipids suggested that its interaction with phospholipids was stronger than with Triton X-100. Kinetic studies also suggested a difference between the interactions of the enzyme with phospholipids and with Triton X-100. Aggregated enzyme had an apparent Km value for D-lactate similar to that of membrane-bound enzyme after preincubation with phospholipids.


Enzyme-linked sandwich immunoassay of ornithine delta-aminotransferase from rat liver using antibody-coupled glass rods as solid phase.

A macromolecular antigen, ornithine delta-aminotransferase [EC 2.6.1.13] from rat liver (OAT) was assayed by the sandwich procedure using rabbit (anti-OAT) Fab'-beta-D-galactosidase complex and rabbit (anti-OAT) IgG-coupled glass rods as a solid phase. The Fab' fragments of the rabbit (anti-OAT) IgG were conjugated with beta-D-galactosidase [EC 3.2.1.23] from Escherichia coli using N, N'-o-phenylenedimaleimide. The rabbit (anti-OAT) IgG was coupled to the aminoalkylsilyl glass rods using glutaraldehyde. The rabbit (anti-OAT) IgG-coupled glass rods were incubated with OAT and then with the rabbit (anti-OAT) Fab'-beta-D-galactosidase complex. The amount of OAT was determined from the activity of beta-D-galactosidase bound to the glass rods. A minimum of 0.03 fmoles of OAT could be determined by this method and use of the glass rods gave greater reproducibility, and was more sensitive and simpler than use of Sepharose 4B.


Cell envelope proteins involved in the transport of maltose and sn-glycerol-3-phosphate in Escherichia coli.

Two types of proteins are discussed in their role of facilitating the transport of maltose and sn-glycerol-3-phosphate in E. coli. The first protein is the receptor for phage lambda, known to be an outer membrane protein. By facilitating the diffusion of maltose and the higher maltodextrins through the outer membrane the effect of the lambda receptor is to decrease the Km of the transport system without influencing the Vmax of substrate flux. The second protein is a periplasmic protein that is induced by growth on glycerol and is essential for transport of sn-glycerol-3-phosphate in whole cells but not in membrane vesicles. This protein has solely been identified by the use of a two-dimensional polyacrylamide gel electrophoresis of periplasmic proteins in wild-type and mutants defective in sn-glycerol-3-phosphate transport.


Carbohydrate uptake by Escherichia coli.

In contrast to active transport, the uptake of carbohydrates via the phosphoenolpyruvate-dependent phosphotransferase system (PTS) leads to the appearance in the cell of the sugar initially as a 1- or 6-phosphate ester. The components of the PTS that transfer phosphate to the sugar are not absolutely specific for any one sugar. Both their synthesis and their activity are controlled; in the latter, "fine" control, glucose-6-phosphate appears to play an important role. Studies of growth on, and uptake of, galactose by E.coli mutants devoid of components of the PTS and also devoid of active transport systems for galactose, suggest that proteins effecting facilitated diffusion of hexoses may be part of, or be closely associated with, the sugar-specific components of the PTS.


Grouping of beta-haemolytic streptococci with group-specific antibodies absorbed to staphylococcal protein A.

A total of 245 isolates of beta-haemolytic streptococci was grouped by the counter current immunoelectrophoresis method and by co-agglutination with antibody-coated staphylococci. Co-agglutination was found to be simple and accurate, and many commercially available grouping sera were suitable for use in this test, though some of them had to be absorbed to remove cross-reactions.


Solid phase antibody assay by means of enzyme conjugated to anti-immunoglobulin.

A solid phase antibody assay by means of alkaline phosphatase conjugated to antiimmunoglobulin is described. Specially designed microcuvettes were sensitized with influenza A antigen, and antibodies bound to it were assayed by anti-IgG alkaline phosphatase conjugate in a semiautomated photometer equipped with a programmable calculator. The sensitivity was found to be 200 times higher than HI- or CF-techniques, and the interassay variation was so small that twofold changes in antobody activity could be regarded as significant. Results from vaccinees indicated that serum samples could be collected at intervals of three to six days only to reach a serological diagnosis in clinical patients.


Movement of infection between milk tubes, teat cups, and teats with a jacketed airflow cushion in a single chamber teat cup.

Transfer of bacteria between teat cups, between teats of the same cow, and between teats of different cows was investigated by tracer bacteria applied to teat skin and by injection of tracer bacteria or colored fluids into the short milk tube. In spite of the unidirectional flow of milk and air with the single chamber teat cup, no advantage over a conventional system in transfer of tracer bacteria from cup to cup, teat to teat, and cow to cow showed.


Coliform contaminated bedding and new infections.

Ten Holstein cows were bedded on fresh, uncured sawdust seeded with coliform broth culture. Escherichia coli concentrations were maintained at 10(6) colony-forming units/g for the 4-wk experimental period. Ten control cows were bedded with dry shavings. The elevated bacterial contamination caused an increase in contamination of teat ends; however, no new coliform infections occurred.


Identification and study of species specificity of antiphage lipopolysaccharides found in the preparations of bacterial DNA.

A method of isolation of the antiphage agent found in the preparations of bacterial DNA was developed. Chemical analysis of the preparations has shown that according to their qualitative and quantitative composition they are identical to the lipopolysaccharide of the bacterial membrane. On the basis of data on the antiphage activity of the D-LPS from E. coli B and E. coli K12 and on the basis of presumed analogy between the inactivation of the phage by the D-LPS preparations and the phage -- cell interaction it is believed that different parts of the LPS serve as receptors for the phages T7 and T4: O-specific polysaccharide for T4 and core LPS for T7. On the basis of data on the activity of D-LPS of two species of the genus Aerobacter against the phage T7 it is presumed that Aerobacer and Escherichia are related according to the structure of their core LPS.


The agglutinating and immunofluorescent activities of antileptospiral antibodies of human sera and of immunoglobulins M and G.

Microagglutinating and immunofluorescent activities of sera of nine patients with clinically diagnosed leptospirosis were investigated. L. grippotyphosa was found in seven patients, L. sejroe in one and L. icterohaemorrhagiae in one patient. The agglutinating activities of IgM approximated the activities of the whole sera. In five patients the agglutinating activities were found in IgG; in four of them two to three months after the onset of the disease, in one patients a month after its onset. In one patient only the activity of IgG reached the activity of IgM after six months. Immunofluorescent activity was found in IgG in eight patients two to five weeks after the onset of the disease. In seven of these patients the activity of IgG reached or exceeded the activity of IgM three to ten weeks after the onset of the disease. IFAT was found to be poorly specific because of high heterologous titres. In 5 out of 7 patients with L. grippotyphosa, heterologous IFAT titres were reduced or eliminated by carrying out the reaction with isolated IgM and IgG. However, in patients with L. icterohaemorrhagiae and with L. sejroe heterologous IFAT activity persisted in both IgM and IgG. The study points out the possibility of differentiating an early stage of the infection from convalescence.


A chromium release assay for phagocytic killing of Candida albicans.

Intracellular killing of Candida albicans was measured by a chromium release technique. Appropriate conditons were equal numbers of polymorphonuclear leucocytes (PMN) and 51Chromium labelled C. albicans (10 6/ml), fresh plasma at a final concentration of 2.5%, incubated at 37degreesC for 60 min. Using normal PMNs, 35-71% of releasable chromium was liberated into the supernatant under these conditions. This assay is easy to perform, requires a small amount of blood and offers and objective measurement of intracellular killing of C. albicans.


Modified E-rosette test for detection of total and active rosette-forming lymphocytes.

The human peripheral blood T-lymphocyte population can be demonstrated with an economy of time by using brometlin-treated sheep red blood cells (SRBC). Similarity, the lower affinity, active T-cell population can be determined using intreated SRBC. Both tests are done without serum, or prolonged incubation of the cell mixture, using the same procedural steps reflecting changes as readily as longer test methods.


Passive hemolysis inhibition test for quantitation of serologically active polysaccharides and oligosaccharides in micro amounts.

An improved quantitative micromethod is described for the assay of antigenically active bacterial lipopolysaccharides and their immunodeterminant oligosaccharides. The method which is capable of measuring antigens in nanogram quantities yields the same sensitivity as the microcomplement fixation without the limitations of this method. The use of the method was demonstrated on Shigella sonnei phase 1 and phase ii lipopolysaccharide antigens and immunodeterminants.


Immunohistochemical identification of T- and B-lymphocytes delineated by the unlabeled antibody enzyme method. I. Anatomical distribution of theta-positive and Ig-positive cells in lymphoid organs of mice.

The unlabeled antibody enzyme method was used to delineate the anatomical distribution of lymphocytes positive with a MBtheta and a-MIg in tissue sections of thymus, spleen, lymph nodes and Peyer's patches of mice. The known T- and B-cell areas were established. Moreover, individual B-cells are detected in T-cell regions, especially in the thymus medulla, and in the periarteriolar section of spleen white pulp. Similarly, individual T-cells occur in B-cell areas, namely in the marginal zone of spleen white pulp, in the medullar cores of lymph nodes, and in germinal centers.


Partial purification of human leucocyte migration inhibitory factor (LIF) by immunosorption of supernatant protein contaminants detected by crossed immunoelectrophorsis.

Concentrated supernatants from washed human lymphocytes incubated in serum-free medium were investigated by crossed immunoelectrophoresis. Quantitatively, the most important macromolecules were serum proteins, in particular albumin and degraded products of albumin. No gross difference was detectable between supernatants from concanavalin A stimulated and unstimulated lymphocytes. The degraded proteins were considered to arise as a result of proteolytic enzymes present in both stimulated and unstimulated lymphocyte supernatants. These molecules exhibited almost the same electrophoretic mobility and molecular weight as native albumin, and might therefore be expected to be difficult to separate from some lymphokines by conventional biochemical techniques. Rabbit immunoglobulins to whole human serum proteins together with immunoglobulins against crude supernatants of mitogen stimulated lymphocytes were therefore bound covalently to an agarose matrix. This preparation efficiently removed all detectable proteins from concentrated supernatants of activated lymphocytes as determined by crossed immunoelectrophoresis. Leucocyte migration inhibitory factor (LIF) was recovered almost quantitatively, and a 40-fold purification of LIF was achieved. The technique is rapid, economical and well suited as an initial step for purification of large quantities of LIF.


Conjugation of antibodies with fluorochromes: modifications to the standard methods.

A number of modification to the standard procedures for coupling of fluorochromes to antibodies are described. The suggested procedures result in economies of time, labour and materials, and allow the reliable production of high quality conjugates. The modifications include the use of staphylococcal protein A-Sepharose for (a) a simple one-step procedure for preparation of IgG from whole serum, (b) removal of undigested IgG after pepsin treatment, and (c) concentration of dilute solutions of IgG. Many other details of coupling procedures are discussed, and modifications suggested. Optimally coupled antibodies were separated by linear salt gradient elution from DEAESephadex, and the effects of fluorescein and tetramethyl rhodamine on the antibody isoelectric point studied.


Quantitative studies of peroxidase labeled antibody. I. Indirect staining system analyzed by chessboard titraions.

The sensitivity and specificity of immunohistological staining procedures employing horseadish peroxidase labeled antibody were evaluated with the aid of chessboard titrations. Two indirect staining systems, detecting antinuclear antibody and pemphigus intercellular antibody, were examined with reference to indirect immunofluorescence. In both systems, chessboard titration results showed that plateau titers of serum antibodies appeared to be a function of label content. The plateau endpoints reflected the anti-immunoglobulin concentrations of conjgates. With a conjugate of molar enzyme to protein ratio (E/P) of 1.1, the sensitivity of indirect staining appeared to be equivalent to that of immunofluorescent staining performed with a conjugate with molar fluorescein to protein ratio of 4.8. Sensitivity decreased sharply with conjugates of low E/P rations. Three methods of assaying the peroxidase content of conjugates were evaluated for reproducibility and sensitivity in relation to staining properties.


A rapid immunofluorescent procedure for the detection of specific IgG and IgM antibody in sera using Staphylococcus aureus and latex-IgG as absorbents.

Sera from adults with toxoplasmosis and individuals with anti nuclear antibodies were examined for the presenceof specific IgM and IgG antibodies and for the occurrence of anti-immunoglobulin ("RF") activity both before and after absorption with freeze-dried preparations of protein A-containing Staphylococcus aureus. Such absorption removed most of the IgG present in sera without interfering with the detection of IgM antibody by immunofluorescence, but was relatively ineffective in the removal of "RF". "RF" activity, demonstrable by slide agglutination, was removed by absorption with latex coated with IgG. In order to prevent the possibility of false positive IgM staining in immunofluorescence tests, it is concluded that sequential absorption with latex-IgG particles and protein A-positive staphylococci is essential. Such absorption is technically simple and can be performed on small volumes of serum.


Chemotherapy--one of the causes of transient loss of HLA antigens and lymphocyte polyreactivity in patients with blood diseases and malignancies.

Modifications of HLA antigens (transient loss or polyreactivity) were found in thirty-two of fifty-five examined patients with blood diseases (leukaemia, reticulosis, reticulo- and lymphosarcoma, lymphogranuloma, erythroblastoma) and malignant tumours. In two cases of acute myelosis transient alteration of HLA-A 2 antigen in HLA-A 28 was demonstrated. The relationship of HLA antigenic modification to chemotherapy was established, both by analysis of individual cases and by statistical evaluation of serological results in patients with or without chemotherapy (0-01 greater than P greater than 0-001). Chemotherapy is thus one of the causes for the development of HLA antigen modifications in blood diseases and malignant tumours.


Effect of galactose and sugar substitutes on blood insulin levels in normal and obese individuals.

Eighteen male patients between the ages of 25 and 50 were given on a double blind randomized basis (A) 40 gms. galactose (B) 50 gms. arabinogalactan and 0.11 gm. sodium saccharin (C) 2 gm. methyl cellulose and 0.083 gm. sodium saccharin and (D) 4 gm. galactose, all in 200 ml water. Blood glucose, galactose and insulin levels were determined during a six hour period before and after ingestion. The three first mentioned solutions tasted equally sweet, the fourth was essentially tasteless. None of these feedings altered plasma insulin or glucose levels. It appears that in contrast to other conclusions reached by earlier investigators sweet taste is unable to induce insulin secretion through neurogenic pathways.


Polarity and gradients in lepidopteran wing epidermis. I. Changes in graft polarity, form, and cell density accompanying transpositions and reorientations.

Lepidopteran wing epidermis has certain advantages for studying the spatial organization of cell populations: ease of accessibility and manipulation, large size, an essentially two-dimensional structure, and direct expression by the scale cells of their polarity. Grafting experiments reveal that polarity and density of graft cells as well as overall graft form are functions of a graft's source and its transplantation site; graft polarity is also determined by the orientation of the graft. The results are consistent with the existence of at least one morphogenetic gradient along the proximo-distal axis of the wing's upper epidermal layer. Various gradient models that might explain the experimental observations are considered.


Polarity and gradients in lepidopteran wing epidermis. II. The differential adhesiveness model: gradient of a non-diffusible cell surface parameter.

For explaining the Manduca wing gradient (Nardi & Kafatos, 1976) a model which postulates a proximo-distal gradient in cellular adhesiveness is considered. The model is based on Steinberg's (1963) differential adhesiveness hypothesis. Rosette formation in certain transposed and/or reoriented grafts can be adequately explained by this model. Several predictions, formulated by using the concept of surface free energy as a thermodynamic measure of adhesiveness, have been tested and proven correct. (1) Transposed grafts tend to assume circular forms, which are configurations of minimum free energy. (2) Because of the pressure difference expected across the interface of two cell populations with different surface free energies, cell densities increase in both distally and proximally transposed grafts. As a corollary to this rule, final size of a graft is a function of its distance from the original position. (3) Histological sections of host-graft boundaries suggest minimal cell contact at the interface. In proximal grafts placed in distal regions, cell density is far lower near the host-graft interface, as compared to the high interior density; the peripheries of distal grafts do not show this effect. (4) Juxtaposition of three different wing regions in all possible arrangements yields the expected two-dimensional configurations. (5) Differences in adhesiveness can be demonstrated by allowing two different wing grafts to interact in an essentially neutral environment (i.e. at a leg or antenna site). as the distance between two given graft regions increases, the extent of their final contact decreases. When applied to other insect systems, the model not only offers an alternative interpretation for results currently explained by diffusible substance models, but also accounts for certain features that were unexplained by other models.


Mutants of Escherichia coli K12 unable to use fumarate as an anaerobic electron acceptor.

Mutants of Escherichia coli K12 strain WGAS-GF+/LF+ were selected for their inability to use fumarate as terminal electron acceptor for supporting growth on glycerol or lactate in an atmosphere of H2 plus 5% CO2. Eighty-three mutants were grouped into seven different categories according to their ability to grow on different media and their ability to produce gas during glucose fermentation. Enzymological and genetic studies indicated that the major class (type I), representing nearly 70% of the isolates, lacked fumarate reductase and corresponded to the frdA mutants studied previously (Spencer & Guest, 1973, 1974). Members of a second class (type II) were phenotypically similar to men mutants, blocked in menaquinone biosynthesis. They differed from menA mutants in having lesions in the 44 to 51 min region of the chromosome rather than at 87 min. It was concluded that fumarate reductase and menaquinone are essential for anaerobic growth when fumarate serves as electron acceptor but not when nitrate performs this function. Fumarate reductase and menaquinone are also essential for H2-dependent growth on fumarate. Type III mutants, originally frdB, were designated fnr because they were defective in fumarate and nitrate reduction and impaired in their ability to produce gas. The fnr gene was located at 28-5 min by its cotransducibility with pyrF (5-7 to 9-2%) and trpA (2-7 to 5-7%) and the gene order fnr-qmeA-pyrF-trpA was established. It was not possible to assign specific metabolic lesions to the fnr mutants nor to the remaining classes, which all exhibited pleiotropic phenotypes. Nevertheless, the results demonstrate that functional or organizational relationships exist between the fumarate reductase system, nitrate reduction and hydrogen production.


Mitosis, septation, branching and the duplication cycle in Aspergillus nidulans.

Mitosis, septation and branching were studied in undifferentiated mycelia and leading hyphae of Aspergillus nidulans, a mould which forms incomplete septa. After spore germination, nuclei divided synchronously until germ-tube hyphae contained 8 or 16 nuclei; mitosis occurred when the volume of cytoplasm per haploid nucleus was about 60 mum3. Intercompartment development was not synchronized, consequently mitosis in the mycelium as a whole eventually became asynchronous. During the stage of asynchronous compartment development, the nuclei, septa, branches and total length of undifferentiated mycelia all increased exponentially at approximately the same specific rate. Septa were formed in hyphae in groups of up to nine; the mean time required for the formation of a group of septa was about 9 min. The mean interval between successive cycles of septation in a hypha was approximately the same as the organism's doubling time. There was a highly significant correlation coefficient between septation and branch initiation and most intercalary compartments initially formed a single branch. The volume of cytoplasm per nucleus in a diploid strain was approximately double the value observed for a haploid strain. However, the length of the hyphal growth unit was not affected by ploidy. The study suggests that a duplication cycle can be recognized during mycelial growth which is analogous to the cell cycle observed in unicellular micro-organisms.


Macromolecular syntheses during the cell cycles of yeast and hyphal phases of Candida albicans.

Synchronous cultures of yeast and hyphal phases of Candida albicans showed exponential increases in RNA content and stepwise exponential increases in DNA content. The periods of DNA synthesis in the two phases coincided with one another and with the budding peaks of the yeast phase. Hyphae grown in synchronous cultures also showed an exponential increase in length. The hyphal phase was therefore normal. Hyphal nuclear division occurred after hyphal DNA synthesis. Germination was a unique event for a hypha and unlike yeast bud formation, preceded the first period of DNA synthesis. The exponential increase in RNA and DNA in asynchronous cultures of hyphae in serum paralleled the exponential increase in the numbers of cells in asynchronous cultures of yeasts in defined media. Thus there are no factors in serum which inhibit the normal exponential growth of C. albicans.


Growth on D-lyxose of a mutant strain of Escherichia coli K12 using a novel isomerase and enzymes related to D-xylase metabolism.

Escherichia coli K12 cannot grow on D-lyxose, but a mutant was isolated which can utilize D-lyxose as sole source of carbon and energy for growth. D-Lyxose is transported into the bacteria by the D-xylose permease. The mutant constitutively synthesizes a new isomerase which is not inducible in the parent strain under any of the conditions tested. This enzyme, whose native substrate appears to be D-mannose, fortuitously converts D-lyxose into D-xylulose. Its structural gene is located at around 85 min on the E. coli genetic map, away from other known isomerase genes. D-Xylulose is subsequently catabolized by the enzymes of the normal D-xylose metabolic pathway. D-Mannose isomerase was partially purified and some of its properties were examined.


Rhodanese from Thiobacillus A2: determination of activity by proton nuclear magnetic resonance spectroscopy.

Rhodanese from Thiobacillus A2 was shown by proton nuclear magnetic resonance (NMR) spectroscopy to use dihydrolipoate or dihydrolipoamide as acceptor of the sulphane moiety of thiosulphate with the formation of alpha-lipoate or lipoamide respectively. Correlation is shown between assays of the enzyme activity by NMR spectroscopy and by ultraviolet spectrophotometry.


Immunofluorescence detection of nitrogenase proteins in whole cells.

Fluorescent antibodies (FA) prepared against the Mo-Fe and Fe proteins of nitrogenase from Klebsiella pneumoniae M5aI were used to detect these protein components in toluene-treated whole cells that were actively reducing acetylene. The FA were highly specific, staining only nitrogenase component proteins originating from Klebsiella. Cross-reactions between the FA and purified nitrogenase proteins from other dinitrogen-fixing micro-organisms did not occur, except in the case of Bacillus polymyxa. The tests rapidly and accurately assayed the component proteins in Klebsiella mutants and derivatives to which Klebsiella nif genes had been transferred either by plasmid or by other means. Cross-reactions also indicated the degree of relatedness between nitrogenase proteins from dinitrogen-fixing micro-organisms of various origins.


Plasma membrane ultrastructural differences between the exponential and stationary phases of Saccharomyces cerevisiae as revealed by freeze-etching.

Ultrastructural changes in the plasma membrane of Saccharomyces cerevisiae during the exponential and stationary growth phases were studied by freeze-etching. In the exponential phase, plasma membrane-intercalated particles were distributed randomly. In the stationary phase, several areas of the plasma membrane showed a hexagonal arrangement of particles; these areas appeared to increase with the age of the culture. The polarity of the particles also changed partially: the E-face of the plasma membrane was only sparsely embedded with particles in exponential phase cells, but relatively densely embedded in stationary phase cells. Invaginations of the plasma membrane on the P-face were devoid of particles during both growth phases. Invaginations of the E-face were sparsely embedded with particles in exponential phase cells, but densely embedded with particles in stationary phase cells.


Nomifensine in parkinsonism.

Nomifensine, a tetrahydroisoquinolone antidepressant which facilitates dopaminergic and noradrenergic transmission, was studied in 28 Parkinsonism patients most of whom were also receiving conventional medications. Double-blind evaluations revealed a moderate therapeutic action at a mean dose level of 150 mg daily. Adverse reactions were encountered, similar to those identical by levodopa.


Mouse malaria nephropathy.

Mice were infected with 1X 107 Plasmodium berghei Yoelii parasites intraperitoneally. Circulating parasite, malaria antibody and C3 concentrations were measures: parasitaemia and hypocomplementaemia were transient, but the antibody response was persistent. Animals were sacrificed at intervals and their kidneys examined: a glomerulonephritis associates with predominantly mesangial deposits of C3, IgG1, IgM and some IgA always developed after 7 days and persisted for up to 6 mth. Malaria antigen and antibody were demonstrated within the glomeruli. Microscopic haematuria occurred with proteinuria but without marked deterioration in renal function. Strains producing high and low affinity antibody were equally susceptible to the disease. Treatment with glucocorticoid, immunosuppressive, platelet function inhibiting and/or anticoagulant drugs, or indomethacin from the 1st day of infection failed to prevent development of the disease or to lead to its early cure. Eradication of the infection within its first 3 days prevented glomerular deposition of antibody and complement, and infection with a smaller antigen load followed by later treatment also produced subsequent cure.


The involvement of the preoptic-suprachiasmatic region in the photosexual reflex in quail: Effects of selective lesions and photic stimulation.

Small bilateral lesions of the preoptic and anterior hypothalamic regions completely suppressed the light-induced testicular growth in quail. Photic stimulation was selectively applied to this region using a small pellet of radioluminous paint (RLP). This local photostimulation induced no testicular growth in short day quail. On the contrary, testes were markedly enlarged after RLP was implanted in the tuberal or in the dorsal area of the infundibular complex of short day quail. This response was as large as in controls reared under 18L-6D. It is therefore confirmed that neuronal populations located in the infundibular complex are directly photosensible. No direct photosensitivity was observed in the preoptic and anterior hypothalamic regions and it is suggested that these areas can serve as a relay for retinal information.


Uteroglobin and related biochemical changes in the reproductive tract during early pregnancy in the rabbit.

The macromolecular secretion products of the rabbit uterus are described. The biochemical and biological properties of uteroglobin are considered, and its synthesis and secretion in various endocrinological conditions are described. The release of uteroglobin from the endometrial epithelium is stimulated by progestagens such as progesterone and its synthetic analogues, although its synthesis has not yet been shown to be entirely dependent on progesterone. The biological function of uteroglobin is obscure. Several approaches to this long-standing probelm are discussed, including the passage of uteroglobin into the blastocyst. It is suggested that interference with the passage of uterine components into the blastocyst may inhibit implantation and provide a means of contraception.


Stereological method for estimating relative membrane surface area in freeze-fracture preparations of subcellular fractions.

Microsomal fractions from liver cells are a mixture of vesicles derived from a number of different cellular membranes. These can be differentiated on freeze-fracture preparations by their characteristic density of intramembranous particles. A stereological method is developed which allows the estimation of the relative membrane surface of the various membrane types by using freeze-fracture preparations. The sample is restricted to concave profiles without cast shadow. The numerical frequency distribution of vesicles with respect to particle density is determined. The estimation of relative surface area must consider the effects on sampling of (a) variable size distributions of vesicles and (b) loss of small profiles. Correction coefficients are derived which allow a differential vesicle count to be transformed into an estimate of relative membrane surface.


The preparation of human articular cartilage for scanning electron microscopy.

This paper compares sixteen preparative techniques thought to be of advantage in the study by scanning electron microscopy (SEM) of human articular cartilage surfaces. The adequacy of surface preservation obtained with the techniques, was judged subjectively, first, by the reproducubility of secondary electron images of normal cartilage, and second, by comparing the results with those obtained by reflected light microscopy of the fresh unfixed cartilage surface over a magnification range of X20- X240. Adequate surface preservation was confirmed when cartilage surfaces had been dehydrated through ethanol to propylene oxide and vacuum dried; dehydrated through amyl acetate and quenched in Freon before freeze-drying; dehydrated and passed through amyl acetate at low temperature before freeze drying. Valuable information can be obtained from different specimens by varying the technique of preparation. At different ages, different surface features are best preserved. In a systematic study it has been found essential to adopt a uniform preparative method and to control the results by reflected light microscopy. Even with the most perfect preparation, the surface appearances cannot be identical with those that function under load in vivo.


Lipid losses during processing of cardiac muscle for electron microscopy.

The lipid retaining properties of several methods of processing tissue for electron microscopy (EM) have been assessed quantitatively. Guinea-pig hearts were perfused in vitro at 37 degrees C with 3H-oleic acid bound to albumin. The hearts were fixed by perfusion with 4% glutaraldehyde in 0-1 M cacodylate buffer. Pieces of left ventricle and interventricular septum were removed, weighed and processed for EM. The fluids used at each stage of processing were monitored for loss of radioactive lipid by scintillation counting. Lipids were extracted from the processed tissue immediately before the embedding stage using a mixture of chloroform:methanol (2:1 v/v). Counts from processed tissue were compared with counts from tissue extracted directly after perfusion fixation in order to monitor subsequent losses during processing. A modified version of Epon processing, omitting 100% ethanol, acetone or propylene oxide, gave a lipid retention of only 20-6%. The addition of paraphenylenediamine to the procedure did not improve the retention although this has been shown to be a useful stain for intracellular lipid. Water soluble Durcupan which does not involve ethanol or acetone dehydration has an average retention of 63% with 100% recovery while the lesser known polymer GACH, a mixture of glutaraldehyde and carbohydrazide used both for dehydration and embedding showed a lipid retention of 82% of the counts recovered although recovery was only 69%. An attempt was made to determine which classes of lipids were present in the tissue after perfusion fixation using thin layer chromatography. It was found that the presence of any of the processing fluids affected the polarity of the lipids and their rates of migration on thin layer plates.


Scanning electron microscopy of renal vascular casts.

The use of Cementex to form casts of the renal vascular system is described. These casts are useful in delineating the vascular microarchitecture of the kidney including that of the glomerular capillaries, but do not appear to reproducibly reflect physiological vascular tone. The postglomerular vascular system is often incompletely filled using this technique. The amount of filling can be altered by the techniques used in cast preparation. The effect of perfusion pressure, concentration of Cementex, fixation, and type of colour additive are compared with respect to the cast structure.


Selective disadvantage of non-functional protein synthesis in Escherichia coli.

Comparison of growth rates of isogenic strains that synthesize varying levels of beta-galactosidase during continuous culture on non-inducing medium indicates that synthesis of low levels of non-functional protein has a small but possibly significant effect upon growth rate.


Effects of aspartame in young persons during weight reduction.

Given the potential use of a low-calorie sweetener during weight reduction, a toxicity study of chronic aspartame ingestion was conducted. Particular attention was given to possible long-term effects of aspartame on the fuel hormonal alterations characteristically caused by weight reduction. As a group mean age was 19.3 yr, body weight was 164.6 lb, and mean height was 65.4 in. Subjects were an average of 33% in excess of ideal body weight. The aspartame dose was 2.7 g/day and was compared on a double-blind randomized basis with a lactose placebo. Both materials were given in gelatin capsules. An average of 6.9 +/- 1.5 lb was lost by the aspartame group during the 13-wk study on a calculated 1,000-calorie diet. The placebo group lost 4.5 +/- 1.2 lb (no significant difference between the two groups). After an overnight fast, reductions in glucose and immunoreactive insulin were seen in both groups, while rising trends in immunoreactive glucagon were observed. These changes are all characteristic of calorie restriction. In no instance was there a detectable effect of the ingested aspartame. No meaningful effect of weight reduction or aspartame was seen on plasma triglyceride and cholesterol, nor on any other parameter of hematologic, hepatic, or renal function that was measured. Similarly, side effects were equally distributed between asparatame and placebo.


Use of aspartame in phenylketonuric heteroxygous adults.

Asparatame, a new artificial sweetener, was administered to 45 obligate phenylketonuric adults for 28 wk. This new sweetening agent was well tolerated, and no untoward medical or biochemical changes were noted.


Traumatic avulsion of the innominate artery: case report and literature review.

A 20-year-old man had avulsion of the innominate artery from the aorta caused by blunt trauma to the chest. A widened mediastinum on chest films is the best indicator that such an injury may be present. During repair, the right common carotid blood pressure should be measured by direct arterial puncture after proximal clamping. A distal stump pressure of 50 mm Hg or greater indicates that there is adequate collateral flow via other systems and a shunt will therefore not be necessary. If there is not sufficient collateral flow, then a graft should originate from a new site on the ascending aorta in end-to-side fashion and be sutured distally to the innominate bifurcation or common carotid artery.


The surgical treatment of chronic otitis media in children.

The results of 150 tympanoplasties in patients aged 12 years and under are documented. Seventy-one ears were operated on by a transcanal tympanoplasty, of which 69 were intended to be single procedures but of which 12 required a revision operation. Combined approach tympanoplasty was performed on 79 ears, in which 42 operations were planned to be single procedures, 17 of whom required at least one revision operation. The results are described from the standpoint of control of disease and improvement of hearing. It is concluded that combined approach tympanoplasty can only be justified on a staged basis which has the added advantage of improving the results of ossiculoplasty.


[A case of Fournier's disease (author's transl)].

The authors present a case of overwhelming gangrene of the cutaneous covering of the external genital organs, of erysipelatous appearance with hemolytic streptococci. Symptomatic treatment, then recovering with a thin graft enabled recovery with an adequate plastic result.


[Comparative results of cephacetrile with cefazolin in complicated urinary tract infections by means of double-blind trials (author's transl)].

In order to elucidate the usefulness of cephacetrile (CEC), comparative trials with cefazolin (CEZ) were carried out in the patients with complicated infections of the urinary tract, and the following results were obtained: 1. There were no statistically significant differences or tendencies observed between the groups given CEC and CEZ in either of the global effects, bacteriological effects, rate of superinfection, relapse, relapse with bacterial alternation, drug usefulness, rate of improvements in symptoms and findings in all the cases. 2. According to a result of stratified analyses, there were statistically significant differences observed, showing more inferior results of CEC than CEZ in either stratum of "below 50" in the age, "acute" in the disease phase, "infections of the upper urinary tract" in the disease pattern, and "E. coli including mixed infections with gram-positive organisms" in the pathogenic strains. However, it should be taken into consideration that certain background factors influence greatly in the effects and there were some problems on deviated backgrounds in these strata. On the other hand, CEC displayed better bacteriological effects than those of CEZ in higher stratum of "chronic" in the disease phase and "Klebsiella, Proteus, Citrobacter, Enterobacter including mixed infections" in the pathogenic strains, and statistically significant differences were not observed. 3. In consequence of bacteriological studies, CEC showed stronger resistance than CEZ against beta-lactamase produced in all the strains of gram-negative bacilli. Particularly there were significant differences or tendencies observed in those of Proteus, Cirtobacter, and Enterobacter, and at the same time there were great differences in the activity of beta-lactamase between CEC and CEZ as the substrate. 4. In correlation of the MIC and effects, CEC showed weaker actions than CEZ against susceptible organisms, but slightly stronger actions against moderately or highly resistant strains. A study of the relationship between the MIC of pathogenic strains, beta-lactamase, and bacteriological effects, showed possibilities that even the high activity of beta-lactamase results in remarkable effects in susceptible strains and the drugs with stronger resistance against beta-lactamase given better results in moderately or highly resistant organisms. 5. The incidence rate of adverse reactions was 2 out of 51 cases in the CEC group (3.9%) and 3 out of 50 cases in the CEZ group (6.0%), showing no significant difference, and those symptoms were similar. In conclusion, when the usefulness of CEC in complicated infections of the urinary tract is compared with that of CEZ, the former is said to be equal to the latter without significant difference as a whole...


[A clinical evaluation of the effect of cephacetrile on bacterial pneumonia. A comparative test with cefazolin by a double blind method (author's transl)].

The therapeutic efficacy of cephacetrile (CEC) in bacterial pneumonia was evaluated in contrast with that of cefazolin (CEZ) by a double blind method. Both drugs were administered via intravenous route at a dose of 1 g twice daily for 14 days. 1) Of 81 patients, each 2 from both groups were eliminated from the study because of unknown results. In CEC group, 36 out of 38 obtained a slightly effective or better results (94.7% of effectiveness). In CEZ group, 31 out of 39 showed a similar result and there was no significant difference between the two groups. 2) In more detail, CEC achieved significantly better results in AaDo2 and cardiac insufficiency than CEZ, and this trend was also seen in dyspnea. 3) Regarding background factors, pretreatment severity was slightly in favor of CEC. However, so long as supplementary analysis is concerned, we could not find any relation between the pretreatment severity of symptom and drug efficacy or improvement of symptom. 4) Since there was a slight bias in the background factors, it is difficult to conclude that CEC is better than CEZ in terms of effectiveness. However, we consider CEC is superior to CEZ if compared in details. 5) Both drugs had the same incidence of side effect (6.25%, 3/48 in both groups). When clinical efficacy of CEC in bacterial pneumonia is evaluated together with the incidence of side effect, we may consider that CEC is an effective antibiotic agent equal to or better than CEZ.


Role of the kidney in the development and maintenance of hypertension caused by renal segmental infarction in the rat.

Utilizing the microsurgical method of transplantation in the rat, the role of the kidney in an experimental renal hypertension due to segmental renal infarction was studied. When the infarcted kidney was transplanted into the bilaterally nephrectomized recipient, hypertension developed so long as the donor kidney was transplanted within 2 weeks after infarction. With transplantation of the normal kidney into the hypertensive rat 8 weeks after infarction, BP remained high unless the infarcted kidney was removed. PRA after transplantation, or KRA of the transplanted kidneys were not correlated to the blood pressure levels. It was suggested that the infarcted kidney has the pressor mechanism, lasting for 2 weeks or more after infarction. The infarcted kidney also has the maintenance mechanism, establishing 8 weeks after infarction.


Studies on the effect of phytagglutinins on some members of Enterobacteriaceae.

Extracts of twenty seeds were tested against twenty six organisms belonging to Klebsiella, Proteus, Salmonella, Shigella and Cholera species. Extracts of eleven seeds showed agglutinating activity against twenty four various organism. S. typhi and Kl. aerogenes did not react against any lectin. On the basis of the results it was possible to differentiate various Shigella and Salmonella organisms by various seed extracts. Different isolates of cholera organisms of same serotype and phage type showed different reaction suggesting that probably these organisms possess different antigenic characters. Thus phytagglutinins may be of some help in the identification and subtyping of these organisms.


[Potentials of a system of adjusted orthogonal leads in the diagnosis of myocardial infarct].

Results of machine-made diagnoses of myocardial infarction based on orthogonal leads of the SVEC-III system, as modified by L.I. Titomir, are presented. In view of the fact that local changes in V3 lead are not always expressed in orthogonal leads there were constructed statistical algorythms of the myocardial infarction diagnosis according to X, Y, Z leads and from X, Y, Z, V3 and Y, Z, V3 leads. The algorythms are constructed on the ground of aposterioral probabilities calculated from the Baves formula. The diagnosis was established with reference to the QRS complex, which proved to be the most valuable diagnostic parameter.


[Fluid redistribution between the extracellular medium and the cells in the diuretic therapy of cardiac insufficiency].

The antipyrine and thiosulphate spaces were measured in patients with circulatory insufficiency of the II B and III stages before and after medication with cardiac glycosides and diuretics, used in various combinations and in courses of different duration and also in 2-week long courses of treatment with ethacrine acid and aldactone in order to study the nature of changes in the water-electrolyte exchange in cardiac insufficiency following diminution of edemas occurring under the effect of an effective therapy. The main indication of cardiac insufficiency, the expansion of the extracellular space, was found to continue even after a clinically effective treatment and complete disappearance of edemas. When myocardial contractility continues to be at a low level and the aldosterone activity is high--the removal from the organism of a large quantity of fluid with the help of diuretics, while reducing the external clinical manifestations of the edematous conditions, aggravates at the same time the pathological nature of the fluid distribution between the extracellular medium and the cells, this being due, in the main, to the reduction in the amount of fluid in the cells. The differences between ethacrine acid and aldactone find their expression not only in a greater of smaller effectiveness of their diuretic action, but also in the influence which they exert on the regulation of water metabolism in cardiac insufficiency.


[Comparative pathology of the microcirculatory bed].

This paper presents an analysis of publications, mostly by Soviet authores, on clinical studies and morphological examinations of the microcirculatory bed in different pathology. It is concluded that the microcirculatory bed should be regarded as an integral system responding to the pathological effects by a local and general reaction of its structural components and by changing the rheological properties of blood. Two types of changes develop in the microcirculatory system -- sterotyped ones, typical for extreme states (various kinds of shock, hypertensive crisis, stress situations), and those specific for certain diseases (diabetes melitus, essential hypertension, athersclerosis, collagenoses, etc.). In all the above diseases the pathological process affects the functional structures of microcirculation that undergo a rearrangement in accordance with the requirements of the body. In the initial period of the disease this re-arrangement is of a compensatory nature and passes ahead of the clinical manifestations. A comparison of the pictutrs obtained by biomicroscopy of the bulbconjunctiva of the eye and of other mucosae with film preparations of the serosae demonstrates their complete similarity. Therefore, the method of biomicroscopy of the eyeball and of the mucosae as a method reflecting the state of microcirculation in the body as a whole should become an integral part of the clinical examination of patients.


[Comparative evaluation of the effectiveness of diuretics].

The study was conducted in 118 patients with cardiac and pulmonary lesions, aged 18 to 75 years. Among the diuretics the leading role belongs to Uregyt, and Lasix, as judged by their natriuretic and diuretic action, then follow Nuvorit, Hypothiaside and Brinaldix. Renese (polythiaside) produces the same diuretic effect as Nuvorit and Hypothiaside. Renese, Hypothiaside, Lasix and Uregyt enhance kaliuresis and often reduce potassium blood plasma concentrations, while Nuvorit and Brinaldix increase kaliuresis least of all, and often increase the potassium blood plasma level. Within two days of discontinuing Thriamterene nearly all body potassium that was retained under the effect of this drug is excreted. Nuvorit, Hypothiaside, Renese, Brinaldix, Lasix, Uregyt cause similar changes in the acid-base balance (respiratory and metabolic alkalosis), and produce no effect upon the acid-base balance rather seldom. Lasix and Uregyt cause metabolic alkalosis more often than other diuretics. Apart from that, Hypothiaside also causes respiratory acidosis in 1/4 of the patients.


[Plasmorrhagia into the myocardial cells after adrenaline-induced myocardial damage].

The immunomorphological and electron microscopy methods were used to study the myocardial damage in mice induced by adrenaline injections. The dynamics of plasmorrhagia was characterized by initial deposition of fibrinogen-fibrin mainly in the area of the sarcolemma of the myocardial cells followed by diffusion into the muscular fibres.


[Evaluation of clinical study methods in the diagnosis of cardiac insufficiency in myocardial infarct].

On the basis of an examination of 500 patients with myocardial infarction the authors undertook a critical analysis of the informativeness of some clinical methods of evaluation of the cardiac muscle contractility employed in this pathology. The authors concluded that attempts at assessing the contractility of the left ventricle on the basis of the temporal intervals of the mechanical systole alone may give misleading results in myocardial infarction patients. The dp/dtmax parameter cannot serve as an independent measure of the inotropic function since its changes largely depend on the conditions of the ventricular load.


The age of the castrato voice.

In our time of rapidly changing life styles it is useful to understand that voices also mirror the spirit of an era. The study of the history of vocal styles may give valuable clues to a better understanding of contemporary phenomena. The age of the castrato voice is a remarkable episode. It illustrates the important role that the human voice plays in expressing psychological undercurrents of an age, and it throws some light on the powerful forces that influence the change of tastes and ideals in cultural history.


Language in childhood psychosis: a review.

Childhood psychosis is a group of disorders characterized by numerous behavioral abnormalities, the most significant of which may well be in the area of language. Absence, delay, or deficit in linguistic development are frequently contributing factors to the retardation often associated with childhood psychosis. The literature on language in childhood psychosis covering the general characteristics of the linguistic deficits, the importance of language in diagnosis and prognosis, mother-child linguistic interaction, and intervention programs is reviewed. Recent psycholinguistic studies in normal development point up the present inadequacies or lack of structural linguistic studies in childhood psychosis. Some assumptions about innate linguistic capacities prerequisite to normal development are discussed and a hypothesis relating to a dysfunction in these capacities in childhood psychosis as well as directions for further research are proposed.


[Arterial stenoses after kidney transplantation].

After 268 kidney allotransplants, 7 cases of renal artery stenosis were observed. An additional 3 patients were referred to use from another center. The outstanding symptom of all 10 patients was hypertension refractory to medical treatment, beginning not later then 10 months after transplantation. In 9 cases there was a murmur over the transplant. In 6 patients hypertension was accompanied by a deterioration of renal function which was resistant to antirejection therapy. The tentative diagnosis was confirmed by selective renal arteriography of the transplant. Two main types of stenoses could be diagnosed: Segmental stenoses, 0.5-2 cm distal to the anastomosis, which were due to intimal lesions caused during removal of the kidney or by the perfusion canula; and kinking stenoses due to a technically inadequate implantation. Hypertension was controlled in all but 1 patient with reconstruction of the artery. Therefore, hypertension after kidney transplantation refractory to medical treatment should be further investigated with selective renal arteriography of the transplant. Stenoses with clinical symptoms which are confirmed by arteriography should be surgically corrected.


[Clinical results of esophagojejunoplication (author's transl)].

Indications, surgical technique, and clinical results in esophagojejunoplication are shown. In 46 patients the indication for total gastrectomy in 20 cases was a benign disease and in 26 cases cancer of the stomach. An essential feature of this method is the construction of a jejunal cuff, which is drawn around the anastomosis and the terminal esophagus. Particular advantage is the security of the anastomosis; we have observed only three leakages and these were without complications (6.5%). The fatality rate was 8.5%, and the total rate of complications was 26.1%. With 30 surviving patients a postoperative follow-up was carried out, the results of which are shown. Jejunoesophageal reflux occurred in only 7.9% of these patients.


The effect of a collagen dressing on contaminated surgical wounds in rats.

In maintaining the rat, the collagen dressings, Aviderm Amine and Aviderm, are as effective as skin in low bacterial levels in contaminated surgical wounds. In the scald-burn wound in the rat the effect of skin dressing is confirmed. Also, 48 h after collagen dressing in the wound the bacterial contamination was the same as that seen under autograft dressings. We have elsewhere suggested that skin and some other dressings modify the local host defense by their effect on the accumulated white blood cells. We believe that collagen, as well as some synthetics, can alter the local environment permitting the destruction of invading bacteria by the accumulated white blood cells.


[Experimental repair of tendons with cutis grafts. Light and polarization microscopic study (author's transl)].

Autologous and homologous cutis grafts have been used for the repair of experimental defect of the tendon of the m. ext. carpi ulnaris in adult dogs. Newly formed tendon tissue was found on the frame of the cutis graft about 8 weeks after the implantation. The structure of the newly formed tendon was investigated by light and polarization microscopy up to 8 weeks postoperatively.


Antimicrobial action of dodecyldiethanolamine: induced membrane damage in Escherichia coli.

Studies on the uptake of the antimicrobial agent N-dodecyldiethanolamine by Escherichia coli show that it rapidly penetrates the cell wall and damages the cytoplasmic membrane. Membrane damage is evident from the induced release of potassium ions and other cytoplasmic components from whole cells and from the lytic effect upon isolated spheroplasts. Concentrations of 0.4 mM and below lyse spheroplasts whereas higher concentrations cause coagulation of the cytoplasm which prevents lysis. The effect of membrane damage upon glucose oxidation in whole cells is also dependent upon the concentration of dodecyldiethanolamine. Concentrations of 0.4 mM and below stimulate oxygen uptake and higher concentrations inhibit it.


Identification of an antibody binding site in the phase-1 flagellar protein of Salmonella typhimurium.

A synthesized pentapeptide equivalent to a region of the phase-1 flagellar protein of Salmonella typhimurium was found to be specifically bound by antisera possessing agglutinating activity against the phase-1 flagellar antigen i.


[Spheroplasts of Proteus studied by scanning electron microscopy, freeze etching and ultrathin sections].

Spheroplasts are formed 15 min after the addition of penicillin. Swellings appear at the end or in the middle of the cell. Buds were found on the surface of the spheroplasts. As was found by scanning electron microscopy, the surface of the spheroplasts is folded and, during later stages, wrinkled. "Expulsion" of mesosomes into the periplasmic space was found, as well as separation of vesicles, formed by the outer and cytoplasmic membranes, from the cell surface. The two fracture faces of the outer membrane are uncomplementary; the convex fracture face is mainly smooth but contains occasional dents of the rod-like shape while the concave face does not contain them. The outer (true) surface of the cell wall is smooth. The similarity and differences between the protoplasts, spheroplasts and L forms are discussed . The protoplasts and spheroplasts may divide, grow and multiply under definite conditions of cultivation, like the L forms do, but they do not possess the well developed intracytoplasmic membrane system typical of the L forms.


[Mechanism of bacterial resistance to tetracyclines and the importance of structural elements of tetracycline molecule for induction of resistance].

The resistance of Staphylococcus aureus P-282 and E. coli E-107 to chlorotetracycline is based on the acquired ability of energy-dependent "counteraction" with regard to penetration of the antibiotic in to the cells. Thus, inhibitors of energy processes stimulate chlorotetracycline absorption by resistant strains and increase their sensitivity to the antibiotic. The studied bacterial hospital strains absorb chlorotetracycline by means of oxalacetic acid transport system similar to resistant strains obtained in the laboratory. The transport system of chlorotetracycline is stereospecific and is involved in absorption of analogues of the antibiotic with the intact phenoldiketone or diphenol structure of the molecule. These analogues, like the natural antibiotic, induce an increase in the resistance to the antibiotic. No changes in the nature of the antibiotic transport system occur during induction. The increased resistance caused by induction is due entirely to a decrease in absorption of the antibiotic by the cells.


[Viability of Escherichia coli cultures].

In the logarithmic phase of batch cultures of E. coli B and MRE-600, a high percentage (upto 80%) of the cells did not grow. Viability of the cells was estimated by inoculation on plates, in agar drops, and on slides. As was established by mathematical planning experiments, the viability and growth rate of the culture depend on the micro-element composition of the medium.


[Rapid selection of microorganisms belonging to the genus Pseudomonas and the order Actinomycetales and producing exocellular lecithinases].

A rapid and simple method is suggested for primary selection of microorganisms producing exocellular lecithinases; the method is based on diffusion of the enzyme into agar containing lecithin. Among 55 studied cultures belonging to the genus Pseudomonas 18 cultures were active. Among 326 studied strains belonging to the order Actinomycetales, 7 strains were active and their level of lecithinase biosynthesis was much higher.


[Dynamics of accumulation of extracellular proteins of Serratia marcescens and their nuclease activity during cell growth].

Serratia marcescens, strain B-10 M-1, liberates an unspecific endonuclease into the extracellular nutrient solution. Two peaks of the enzyme activity were found in the cultural broth during growth of the cells. The dynamics of accumulation of protein fractions in the cultural broth was studied, and the relative electrophoretic mobility of the enzyme-active part of the proteins was established.


Optimal dose of a thiazide diuretic.

In essential hypertension, 25 mg and 100 mg of chlorthalidone per day reduced blood pressure to a similar extent. The larger amount (100 mg per day of chlorthalidone) caused a greater reduction in extracellular volume and a larger rise in plasma renin activity and serum uric acid levels. Hypokalaemia was common with 100 mg per day of chlorthalidone, but was rarely seen in patients who took 25 mg per day, and neither dose caused total body potassium depletion. In the management of hypertension, 25 mg of chlorthalidone is the preferred dose as it produces most of the antihypertensive effects with only minor biochemical changes.


Comparison of effectiveness of mefenamic acid and ibuprofen in treatment of rheumatoid arthritis.

This paper reports a double-blind crossover trial comparing mefenamic acid (1500 mg/day) with ibuprofen (1200 mg/day) in the treatment of patients with rheumatoid arthritis receiving maintenance salicylate therapy. Both drugs were used in three divided doses. Mefenamic acid compared favourably with ibuprofen. In the adopted dose regimes the side effects from both drugs were mild and almost exclusively gastrointestinal.


Restriction endonuclease analysis of ribosomal DNA from Saccharomyces cerevisiae.

The size and degree of homogeneity of the repetitive units in purified ribosomal DNA (gamma DNA) from Saccharomyces cerevisiae have been analyzed by restriction endonuclease digestion and heteroduplex mapping. Digestion of the gamma DNA with EcoRI yields seven fragments, digestion with Hind II+III yields five fragments, digestion with Hind III alone yields two fragments, and digestion with Sma I yields one fragment. The sum of the fragment molecular weights after digestion with each of the endonucleases is 5.5-5.6 x 10(6). When the DNA strands of the Sma I fragment are dissociated and reannealed, only homoduplexes are formed. We have concluded from these results that the repeating units in yeast ribosomal DNA are 5.6 x 10(6) datons and are homogeneous in size and composition.


Overproduction of phage lambda repressor under control of the lac promotor of Escherichia coli.

The gene coding for bacteriophage Lambda repressor (cI gene) has been fused to the lac operon of Escherichia coli. In some of the fusions Lambda repressor synthesis can be controlled by the lac operator and promoter. Upon induction of the lac operon the amount of Lambda repressor is increased by a factor of 7 over that found in a single lysogen. In combination with the polarity suppressor suA the induction factor rises to 20. Transducing phages of one fusion were constructed. After thermal induction of this phage the final level of Lambda repressor was enhanced by a factor of 150.


[Theory and practice in the taking of complete denture impressions].

The fundamental principles applicable to complete dentures are examined. Particular attention is given to the anatomical state of the so-called "biostatic areas" and the importance of a positive load: support ratio between the dental plate and biological tissue. The fundamental principles relating to the taking of impressions are discussed and stress is laid on the importance of imparting a functional character to the relief. Various techniques for the construction of a correct plate and their advantages and disadvantages are illustrated. Reference is made to preliminary impressions, resin spoons, the functional nature of the peripheral edges, and final impressions, with or without compression.


A novel class of Saccharomyces cerevisiae mutants specifically UV-sensitive to "petite" induction.

A mutant of Saccharomyces cerevisiae has been isolated which, though exhibiting a normal response to nuclear genetic damage by ultraviolet light (UV), is more sensitive than its wild type specifically in the production of the cytoplasmic (rho-) mutation by this agent. Some of the features of this mutation which has been designated uvsrho 5 are: i) The mutation is recessive, it exhibits a Mendelian, and hence presumably nuclear, pattern of segregation, but manifests its effects specifically and pleiotropically on mitochondrial functions. ii) Mutant cells resemble their wild type parents in a) growth characteristics on glucose; b) in their UV induced dose response to lethality or nuclear mutation and c) the ability of their mitochondrial genome, upon mating with appropriate testers, of transmitting and recombining various markers, albeit with enhanced efficiency. Similarly, d) they are able to modulate the expression of mitochondrial mutagenesis by ethidium bromide. Thus their mitochondrial DNA appears genetically as competent as that of the wild type. iii) Mutant cells differ from their wild type parents in a) growth characteristics on glycerol; b) susceptibility to induction of the mitochondrial (rho-) mutation by various mutagens, in that the rate of spontaneous mutation is slightly and that by UV is significantly enhanced, whild that by ethidium bromide is greatly diminished. Conversely, c) modulating influences resulting in the repair of initial damage are diminished fro UV and stimulated in the case of Berenil. iv) The amount of mitochondrial DNA per cell appears elevated in the mutant, relative to wild type, and its rate of degradation subsequent to a mutagenic exposure to either UV or ethidium bromide is diminished. v) A self-consistent scheme to account for this and all other information so far available for the induction and modulation of the (rho-) mutation is presented. In a previous study it was shown that some nuclear mutants of Saccharomyces cerevisiae, more sensitive to lethal damage induced by ultraviolet light (rad) than their parent wild type (RAD), also exhibit a concomitant modification in sensitivity to both nuclear and cytoplasmic genetic damage (Moustacchi, 1971). However, another class of rad mutants respond to the induction of the cytoplasmic "petite" also designated as rho- (or rho-) mutation by UV in a manner indistinguishable from that of the RAD strain. One possible interpretation of this last observation is that some of the steps in the expression of the UV damage on mitochondrial (mt)DNA may be governed by other nuclear and cytoplasmic genetic determinants, the products of which may then act specifically on mitochondrial lesions. If this assumption is correct, it should be possible to find mutants with a normal response to nuclear damage but specifically UV-sensitive towards induction of (rho-)...


Conditional lethal phosphatidylserine decarboxylase mutants of Escherichia coli. Mapping of the structural gene for phosphatidylserine decarboxylase.

The final step in the biosynthesis of phosphatidylethanolamine, the major membrane lipid of Escherichia coli, is catalyzed by the membrane-bound enzyme, phosphatidylserine decarboxylase. A variation of a procedure for localized mutagenesis (Hong and Ames, 1971) was employed to generate conditional lethal mutants in phosphatidylserine decarboxylase. In our modification, an episome carrying the psd gene closely linked to purA+ was heavily mutagenized in vivo in a strain also lysogenic for phage P1CMclr100. After induction of a phage lytic cycle, the purA+ marker was transduced to a purA- recipient. A majority of the Pur+ transductants thus contained a psd gene originating from the heavily mutagenized episomal strain. Three mutants were isolated in which temperature-sensitive growth is caused by thermosensitive phosphatidylserine decarboxylase activity that is defective in vivo at the non-permissive temperature. All 3 mutations were mapped at the same location as psd1, being cotransduced with melA, purA, and ampA. The gene order in this region, as determined by a phage Pl-meidated, three-factor cross is ampA-psd-purA. psd+ is dominant to the psd mutant alleles.


A map of the restriction targets in yeast 2 micron plasmid DNA cloned on bacteriophage lambda.

The 2 micron circular DNA from S. cerevisiae has been cloned on bacteriophage lambda. The two forms of circular DNA which exist in equilibrium due to recombination between inverted repeat sequences were separated as stable clones, and a map of targets for restriction endonucleases EcoRI, HindIII and HpaI was constructed. The circular DNAs isolated from a particular oligomycin resistant strain and its parent oligomycin snesitive strain were compared by restriction endonuclease analysis, and no difference was detected. The potential uses of cloned 2 micron DNA in determining the possible biological role of these plasmids are considered.


In vitro transcription of the tryptophan operon in isolated bacterial nucleoids.

In vitro transcription of the trp operon in isolated nucleoids from Escherichia coli was studied. RNA synthesis in this system occurred primarily as a continuation of transcription which had been initiated in vivo; little or no initiation of new RNA chains was observed. Transcription of the trp operon in nucleoids by endogenous RNA polymerase procedded efficiently and ceases sequentially in the order of the gene sequence within the operon. Under these conditions, no appreciable exonuccleolytic digestion of nascent 3H-RNA was found, though some endonucleolytic cleavage was generally seen. Little or no incorporation of 14C-leucine into polypeptides was observed, inspite of tha fact that considerable number of ribosomes and nascent RNA chains were found attached to the isolated nucleoids. The synthesis of trp mRNA continued in the presence of chloramphenicol or fusidic acid, or under conditions where the rebosomal translocation factor G was inactivated. From these and other kinetic studies of trp mRNA synthesis in nucleoids obtained from nonsense strong polar mutants of the trp operon, it was shown that transcription in nucleoids was not connected functionally with transloational processes and thus unable to exhibit polarity effected by a nonsense mutation or by general translational blockage. In studies employing nucleoids from nonsense strong polar mutants of the trp operon, it was demonstrated that RNA polymerase are scantily distributed over the region downstream from the nonsense mutation site of the operon, thereby supporting a notion that in vivo transcription is eventually terminated near the nonsense mutation.


Genetic analysis of mutants from Escherichia coli K12 unable to grow anaerobically without exogenous acceptor.

The ana mutation leads E. coli to need an exogenous electron acceptor for anaerobic growth. The affected gene maps near 26 min between chl C and tdk on the chromosome of the organism.


Temperature-sensitive mutants of the slime mould Physarum polycephalum. I. Mutants of the amoebal phase.

A replica plating method for isolating it amoebal mutants of Physarum polycephalum has been devised. Temperature-sensitive mutations occur at a frequency after nitrosoguanidine mutagenesis of 10(-3) per survivor, are stable but are not usually expressed in the plasmodia formed from these amoebae in clones. Some of these mutants appear to be cell-cycle stage specific.


Temperature-sensitive mutants of the slime mould Physarum polycephalum. II. Mutants of the plasmodial phase.

Methods are described for the isolation and testing of temperature-sensitive plasmodial strains of Physarum polycephalum. Nineteen temperature-sensitive strains were found by screening plasmodia derived from mutagenised amoebae and the properties of these are described. A scheme is outlined for the detection of specific mitotic cycle lesions amongst temperature-sensitive strains, and the properties of a presumptive mitotic cycle mutant are described.


Cloning of calf thymus satellite I DNA in Escherichia coli.

The 1400 base pair repeat produced by digestion of calf satellite I DNA (phi = 1.714 g/cm3) with EcoRI, was cloned in E. coli. The hybrid plasmid (pGM 214) which contains the ColE1-Ap vector (pSF 2124) and the 1400 base pair fragment replicates stably in E. coli and can be amplified by chloramphenicol treatment. No clone was found in which more than one "repeat unit" of the satellite I DNA was present in the chimaera plasmid. Digestion of the original satellite I and the plasmid pGM 214 with R-SmaI shows that the satellite DNA replicated in E. coli is cleaved by the restriction endonuclease SmaI whereas the original satellite I DNA from calf thymus is not, suggesting that the satellite I contains a large amount of modified cytosine or guanosine, probably 5-methyl-cytosine. R-EcoRI* produces a number of fragments with the satellite I in the range of 300 base pairs to 1400 base pairs. A physical map of pGM 214 (and pSF 2124) with R-EcoRI, R-HincII, R-HindIII, R-SmaI, R-BamI and R-EclI was constructed. The 1400 base pair "repeat unit" in the pGM 214 is efficiently transcribed in vitro by purified RNA polymerase, starting from a pSF 2124 promoter. The restriction enzyme EclI produces a 350 base pair repeat with calf satellite II (phi = 1,722 g/cm3), whereas the satellite I is not cut by this enzyme.


Assembly of the mitochondrial membrane system. XVIII. Genetic loci on mitochondrial DNA involved in cytochrome b biosynthesis.

1. Fourteen cytoplasmic mutants of Saccharomyces cerevisiae with a specific deficiency of cytochrome b have been studied. The mutations have been shown to occur in two separate genetic loci, COB 1 and COB 2. These loci can be distinguished by mit- X mit- crosses. Pairwise crosses of cytochrome b mutants belonging to different loci yield 4-6% wild type recombinants corresponding to recombinational frequencies of 8-12%. In intra-locus crosses, the recombinational frequencies range from 1% to less than 0.01%. The two loci can also be distinguished by mit- X rho- crosses. Twenty rho- testers have been isolated of which ten preferentially restore mutations in COB 1 and ten others in COB 2. 2. The COB 1 and COB 2 loci have been localized on mitochondrial DNA between the two antibiotic resistance loci OLI 1 and OLI 2 in the order OLI 2-COB 2-COB 1-OLI 1. The results of mit- X mit- and mit- X rho- crosses have also been used to map the cytochrome b mutations relative to each other. The maps obtained by the two independent methods are in good agreement. 3. Mutations in COB 1 have been found to be linked to the OLI1 locus in some but not in other strains of S. cervisiae. This evidence suggests that there may be a spacer region between the two loci whose length varies from strain to strain. 4. Two mutations in COB 2 have been found to cause a loss of a mitochondrial translation product corresponding to the cytochrome b apoprotein. Instead of the wild type protein the mutants have a new low-molecular weight product which is probably a fragment of cytochrome b. The fact that the mutations revert suggests that they are nonsense mutations in the structural gene of cytochrome b.


Suppression of temperature-sensitive aminoacyl-tRNA synthetase mutations by ribosomal mutations: a possible mechanism.

The biochemical basis of suppression of a temperature-sensitive alanyl-tRNA synthetase (alaS) mutation by mutational alterations of the ribosome has been investigated. Measurement of the polyU-dependent polyphenylalanine synthesis showed that ribosomes from the suppressor strains are less active than ribosomes from the unsuppressed aminoacyl-tRNA synthetase mutant. In this system no increased translational ambiguity could be detected for the suppressor ribosomes. This fact and also the findings that the ram-1 mutation is not able to suppress the aminoacyl-tRNA synthetase mutation and that presence of the suppressor allele is not accompanied by a measureably improved alanyl-tRNA synthetase activity argue against the possibility that suppression might be due to increased translational misreading rates of the alanyl-tRNA synthetase mRNA. It has been further found that partial suppression of temperature sensitive growth of the alaS mutation can be achieved by independent ribosomal mutations leading to reduced growth rates because of a mutation to antibiotic resistance. Addition of low concentrations of a variety of antibiotics acting at the ribosomal level can also partially revert the temperature-sensitive phenotype of the alaS mutant. Although the possibility cannot be excluded that suppression is due to the stabilisation or activation of the mutant enzyme by some indirect effect of the suppressor ribosomal mutations, the following working hypothesis is favoured at the moment: It is assumed that limitation of the aminoacyl-tRNA synthetase activity in a certain range of the restrictive temperature causes growth inhibition by the premature termination of polypeptide synthesis at the ribosome or by the unbalanced synthesis of the individual cellular proteins under this condition. The mechanism of suppression by ribosomal mutations is proposed to consist of the release of this growth inhibition by the reduction of the rate of polypeptide synthesis, which would keep amino acid incorporation from exceeding the slow charging of tRNA and thus exhausting the pool of charged tRNA. In the suppressor strains, therefore, growth at the semi-restrictive temperature is no longer limited by the aminoacylation of tRNA but by the translational process at the mutated ribosome. This influence of the ribosomal mutation on the speed of translation could be directly or indirectly coupled with an effect on translational fidelity resulting in the prevention of the binding of uncharged or non-cognate charged tRNA or in the tighter binding of peptidyl-tRNA when cognate aminoacyl-tRNA is limiting.


The use of specialised transducing phages in the amplification of enzyme production.

Two types of lambdatrp phages have been used as model systems to investigate ways of optimising the expression of bacterial genes from transducing phage genomes. Excellent yields of trp enzymes were achieved by infecting a trpR- host with Q- or Q-S- derivatives of lambdatrpAM1, which expresses its trp genese exclusively from the trp promoter. The five trp geneproducts constituted more than 50% of the total soluble protein of infected cells under these conditions, and an even higher proportion of the protein synthesized after infection. In a trpR+ host, phage DNA replication was easily able to override tryptophan-mediated repression by titration of the trp promoter were equally productive, while having the advantage of being much simpler to construct and propagate. lambdatrp phages lacking the trp promoter were used to investigate ways of optimising gene expression initiated at the phage promoter, PL. Though very powerful, the latter promoter is more difficult to harness then the trp promoter. Derepression of transcription from PL by the use of cro- mutations is accompanied by poor replication of transducing phage DNA. Attempts to circumvent this difficulty using virulent of cro,cII double mutants have not been successful. Nevertheless, cells infected with a lambdatrp phage expressing its trp genes exclusively from PL made up to 16 per cent of their protein as trp gene-products.


Recombined molecules of mitochondrial DNA obtained from crosses between cytoplasmic petite mutants of Saccharomyces cerevisiae: the stoichiometry of parental DNA repeats within the recombined molecule.

We have studied recombination between repetitive mitochondrial DNAs from cytoplasmic petite mutants of Saccharomyces cerevisiae. Mitochondrial DNA was isolated from two parental p- mutants, carrying respectively the CR and the ER mitochondrial genetic markers, and from two p- CRER diploid genetic recombinants. These two recombinants, obtained from the same parental petites, differ in their degrees of suppressiveness. The p- mitochondrial DNAs were analyzed by DNA-DNA hybridization, high resolution melting and reassociation kinetics. It was found that the repeating unit of the CR parental p- DNA is 3 to 4 times longer than that of the ER parent. There is very little sequence homology between these two p- mitochondrial DNAs and almost all parental sequences are integrated into the recombined molecules. Mitochondrial DNA from both types of recombinants seems to contain the two parental repeating units in the ratio 1:1.


Gal mRNA initiated within IS2.

A strain of E. coli carrying IS2 in the control region of the gal operon has been found to revert to a constitutive phenotype. These revertants can be divided into two classes, which differ in their rate of enzyme synthesis and gal transcription. One revertant synthesizes the gal messenger at a low level (low level revertants), the other at a higher level that exceeds that of the induced wild type two- to three-fold (high level revertants). In both cases it has been shown that the gal messenger is covalently bound to IS2-RNA, which is transcribed from IS2 in the original orientation. The evidence suggests, that the section of the IS2-element, from which this RNA is transcribed in the case of the high level revertants is smaller than 50 nucleotides long: i.e. the resolution of the hybridization method used for the detection of sequence homologies exceeds that of the electron microscopical heteroduplex technique.


E. coli membranes become permeable to ions following T7-virus-infection.

Infection of E. coli with the viruses T7 or T3 leads to a dramatic efflux of potassium ions. This ion efflux is caused by the virus particle since no concomitant protein synthesis is required. T7 mutants carrying deletions in the M-gene (Schweiger et al., 1975), however, yield virus particles disturbed in the ion release.


REPLICAtion of small plasmids in extracts of Escherichia coli: requirement for both DNA polymerases I and II.

The role of the three E. coli DNA polymerases (pol I, II, and III) in the replication of Col E1 DNA and other small plasmids with similar replicative properties was investigated in a soluble in vitro system prepared by freeze-thaw lysis of chloramphenicol-treated cells (Staudenbauer, 1976). Extracts from isogenic mutants of the polA, polB and polC gene loci deficient in pol I, II, and III respectively were examined for their replicative capacity. It was found that polA and polC extracts are deficient in the synthesis of supercoiled plasmid DNA, whereas the polB mutation has not effect. Deficient extracts could be complemented by addition of purified pol I and pol III holoenzyme. Analysis of the in vitro synthesized DNA by alkaline gradient centrifugation indicates that pol I is involved in an early step of the replication cycle whereas pol III is required at a later stage. These conclusions are confirmed by inhibition studies employing arabionsylcytosine triphosphate (aCTP) which is shown to interfere with pol III as well as pol II. The strong inhibitory effect of aCTP on plasmid replication is not influenced by the polB mutation and mimicks the effects of thermal inactivation of polC extracts. It is suggested that aCTP blocks plasmid ENA replication in vitro by interfering with pol III function


Genetic studies of the ribosomal proteins in Escherichia coli. X. Mapping of the ribosomal proteins, L21 and S15, by intergeneric mating experiments between Serratia marcescens and Escherichia coli K12.

Episomes of E. coli, which cover argG but not the str region, were transferred to Serratia marcescens. Ribosomal proteins from these hybrid strains were analyzed with phospho-cellulose or carboxy-methyl-cellulose column chromatography. Two E. coli ribosomal proteins, L21 and S15, could be detected in the ribosome from the hybrid strains in addition to the ribosomal proteins of S. marcescens.