Upper airway obstruction induced by warfarin sodium.

I report a patient in whom warfarin sodium induced upper airway obstruction secondary to a spontaneous nontraumatic hemorrhage into the sublingual space. Treatment of this obstructive sublingual space hematoma with conservative medical management is reviewed. I discuss the role of warfarin sodium in coagulation and in the production of this pseudo-Ludwig phenomenon.


Fiberoptic headlight. Adaptation for observation and teaching.

I describe an optical system that allows an observer exact visualization of the field seen by an examiner or operator of a fiberoptic headlight.


The role of the intrauterine device in contraceptive practice.

Recognition of the rarity of systemic complications of IUD's as compared with oral contraceptives, has increased the acceptability of the IUD. Improvements in the design of IUD's and increased experience in their use have resulted in extension of the range of women to whom IUD's can be offered. Points of practical management are discussed.


Vasectomy: psychological effects and pre-operative counseling.

Modern thinking with regard to the psychological side effects of vasectomy are outlined and the importance of initial motivation stressed. Reasons for anticipating psychological failure are listed. The process of counselling is discussed leading from the patient's statement of reasons for the operation, through his expressed fears of probing his unexpressed fears and thence to an explanation of the procedure and follow-up necessities.


The prevalence of asthma in general practice.

The survey reveals important data about onset of asthma and total attendances for asthma by Australian general practitioners. A comparison is made between data on asthma from the National Morbidity Survey 1962-63, and the Australian General Practitioner's Morbidity and Prescribing Survey 1969 to 1974. A slight male preponderance is demonstrated, most marked in infancy, but also in old age. The hypothesis is propounded that androgens may play a protective role in asthma, but females have a genetic advantage. It is noted that in the 'teens' and early adulthood, there is an increase in female patients. The onset of asthma occurs more often in autumn and spring than in summer and winter. The occurrence of asthma appears to becoming less relative to other disease. Although there was once relatively more asthma in the metropolitan areas compared with non-metropolitan, there is now less.


Promoting discovery as a teaching technique.

What one discovers or learns for oneself tends to be retained for long periods and used effectively in later problem solving. This article examines the reasons for this, suggesting methods and illustrating how one may teach in the clinical environment to achieve such discovery learning.


Methods of diagnosing diabetes mellitus.

The diagnosis of diabetes mellitus depends primarily on the doctor being continually aware of this common, important and treatable disease. The previous two articles in this series have described the prevalence of the disease, and the warning signals suggesting that the disease may be present.


Recent advances in female sterilization.

Advances in female sterilization have been made over the last five years in both its techniques and medico-social acceptance. Prior to 1970, the majority of tubal sterilizations were carried out by partial or complete surgical excision of both tubes by laparotomy in most cases, or by partial salpingectomy by an anterior or posterior colpotomy in selected cases. The traditional operations by the abdominal route comprised the Madlener method, the Pomeroy method, the Irving method and the Aldridge method. These methods will not be discussed further.


The stethoscope as a diagnostic tool.

It is not the purpose of this article to list the stethoscopic findings in various diseases, nor to discuss such conditions in detail, all of which may be found in any good text book of medicine. Rather, an attempt will be made to assess the significance of the stethoscope, with its limitations, in clinical diagnosis. Does it in fact now have a role of any importance, or is it merely carried as the doctor's traditional badge of office?


Eye history and examination in general practice.

Time spent in carrying out a careful history taking and examination allows for accurate detail in making a diagnosis. If doubt occurs, reference to an ophthalmologist--even if only a telephone call--is wise.


The experiences of students and their teachers in a general practice preceptorship scheme.

This article is the result of assessing 140 paired student and preceptor reports from the University of NSW Preceptorship Scheme. Its aim is to present, in an organised and readable form, the feelings of students and preceptors about their experiences in this scheme.


The training of medical students.

A continuing preoccupation, perhaps an occupational neurosis, of Deans and of Medical Faculties seems to be curricular change. It is fashionable, it is progressive, it demonstrates to outsiders the educational dynamic of medicine.


Clinical types of diabetes mellitus.

While it is widely accepted that diabetes mellitus is a disorder characterized by impaired carbohydrate tolerance, there is no clear-cut distinction between normal and abnormal.


Community health centre evaluation. Paper 1: Working patterns of allied health professionals.

Community health centres are a new development on the Australian health scene and current indications are that they may play a greater role in the delivery of primary health care of the future. Therefore, information about these centres, what they are doing and who they are affecting, must be forthcoming if more public funds are to be channelled their way. The study reported here and in subsequent papers attempts an in-depth examination of the Southern Memorial Hospital--Community Care Centre for the purpose of establishing a base line from which this centre can measure its progress and with which other centres providing health care can compare. This paper reports the methodology of the evaluation study and the results of a survey of the working patterns of allied health professionals.


The development of a sunscreen.

Australians generally admire an evenly tanned skin, and the ability to acquire such a tan without much or any discomfort due to burning, is widely prized and envied. Various topical sunscreens have been introduced in order to facilitate the attainment of such a state, and this paper describes the stages in the development of such a product. The final product must obviously contain an active ingredient with the necessary selective filtering properties. This ingredient, and the vehicle in which it is presented, must be free of sensitising properties and must not cause acute or chronic toxic effects. Finally, it must be shown, under various typical conditions of use, to possess overall efficacy in terms of protecting from burning while permitting tanning.


The WHO Regional Teacher Training Centre for the Health Sciences, Sydney.

The inter-relationship between education and training, the development of health manpower, and the quality and relevance of a country's health services is highlighted by the powerful sponsorship and financial support currently being given by the World Health Organization to a primarily educational project in its various regions. The project is designed to improve the insights of health professionals into the art and science of teaching and learning.


Glomerulonephritis in children and adults.

Glomerular disease is associated with a limited number of signs which are easily detected by routine clinical examination and urine tests. Haematuria, proteinuria, oedema, hypertension and renal impairment occur in various combinations including classical and predictable syndromes such as acute post streptococcal nephritis and the nephrotic syndrome in children. Apart from these classical syndromes clinico-pathological correlations in glomerular disease are poor. Early renal biopsy is required to determine the extent of the glomerular disease and the long term prognosis in most patients with prolonged proteinuria and haematuria.


Treatment of arachnid poisoning in Australia.

Most Australian spiders are capable of causing a bite which produces some degree of local reaction and occasionally systemic effects. However, only the Sydney funnel-web spider which is limited to a 160 kilometre radius from the centre of Sydney and the red-back spider which is found in all States are capable of inflicting a potentially lethal bite.


Urinary tract infection in adult women: morbidity without mortality.

This condensed paper deals with that relatively common malady, urinary tract infection in the adult female, from a practical point of view. It serves to emphasise that the great majority of these infections cause distressing morbidity, but little serious renal impairment or mortality. It indicates how the natural history of these infections may be studied to select the minority with serious infection. It stresses the aetiology of urinary tract infection, and thereby indicates a practical management.


Dangerous marine animals.

Tales of dangerous marine animals have flourished, entwining history, legend and imagination. Man is now demonstrating his remarkable adaptability in returning to the aquatic environment, from which he had his origins, and factual knowledge of marine creatures is surplanting mystery, folklore and fear. There is still cause to fear certain aspects of the underwater world, and the one aspect that still holds sway over public interest is that of dangerous marine animals. There is little justification for this top priority. The kelp beds of San Diego will claim more diving victims than all the marine animals around the United States of America. The cold seas off the English coastline, the tidal currents of Hawaii and the multitude of drowning accidents in water caves of Florida and Australia belittle the relatively few fatalities caused by marine animals. Nevertheless, the latter do cause injury and death, especially in the tropical, subtropical and temperate regions. The Indo-Pacific area seems particularly well endowed with a variety of potentially lethal species, and some of these will be dealt with in this paper.


Electrolytic O-demethylation of methoxycatecholamines.

Electrolysis of 3-methoxycatecholamines in physiological solutions resulted in the formation of the parent catecholamines and their oxidation products. Conversion occurred at the anode. Maximal catecholamine production occurred in the presence of ascorbic acid.


Regulation of aldosterone in the guinea-pig--effect of oestrus cycle, pregnancy and sodium status.

The blood concentrations of aldosterone, corticosterone and cortisol were measured in conscious, non-stressed guinea-pigs using a double isotope dilution derivative assay procedure. Aldosterone levels in the guinea-pig were high when compared with those of other species. The concentration of aldosterone, 37-7 +/- 15-9 ng/100 ml (x +/- SD), and cortisol, 31-8 +/- 10-1 mug/100 ml, found in non-pregnant females on a moderate sodium intake was significantly greater than in males (aldosterone 22-2 +/- 2-4 ng/100 ml and cortisol 19-3 +/- 5-7 mug/100 ml). There was no sex difference in corticosterone concentrations; females, 0-25 +/- 0-06 mug/100 ml and males, 0-23 +/- 0-10 mug/100 ml. The oestrus cycle had no effect on levels of the three steroids measured. Two thirds of the way through the 68-day gestation period aldosterone levels were significantly elevated compared with non-pregnant values (68-7 +/- 50-9 ng/100 ml, p less than 0-05). Values at day 20 (33-2 +/- 11-7 ng/100 ml) and day 60 of gestation (51-9 +/- 21-7 ng/100 ml) were similar to those of non-pregnant animals. Cortisol and corticosterone levels were significantly elevated at 20 days gestation and they continued to rise until, at day 60, cortisol was 9 times and corticosterone 4 times higher than the non-pregnant values. Compared with a moderate Na intake, salt loading suppressed aldosterone levels and Na restriction raised them.


The inhibitory influence of the pyloric antrum on gastric secretion in dogs.

The effect of the pyloric antrum and of subsequent vagotomy on the secretory responses of an innervated or a denervated gastric pouch in the dog to histamine and pentagastrin was determined. The increased sensitivity of the gastric pouch to stimulation after these procedures is in keeping with the concept that an inhibitory reflex is concerned with the control of acid gastric secretion.


Streptomycin and temperature sensitivity of colicin-like activity in Salmonella cultures.

Salmonellin production on agar was reduced by adding streptomycin or raising the incubation temperature to 44 degrees. Production of group 3b salcol was increased by incubation at 44 degrees and, for one producer only, by adding streptomycin. Production of the diffusible, nontransferable group 4 salcol and also of diffusible colicin V was reduced at 44 degrees. Group 1 salcol production was unaffected by raised temperature or streptomycin. Group 2 salcol production also was unaffected, except in salm+ transcipients of Arizona So116 where it was reduced along with salmonellin production by incubation at 44 degrees or addition of streptomycin.


The effect of ambient temperature on the growth hormone and prolactin response to exercise.

The effect of a standardised exercise procedure on plasma growth hormone (HGH) and prolactin has been assessed in 10 normal human subjects. Each subject was tested in an ambient temperature of 40 degrees and on a subsequent day at a temperature of 10 degrees. At 40 degrees exercise produced an increase in HGH in all 10 subjects, while in the cold only 1 showed a rise in the hormone during exercise. An increase in prolactin with exercise at 40 degrees occurred in some of the subjects, but these changes were small in comparison with those of HGH. Prolactin levels did not increase during exercise in the cold.


[Electrocardiographic changes in patients with acute leukoses treated with rubidomycin or adriamycin at the Internal Clinic A].

Electrocardiographic changes in patients with acute leukoses treated with Rubidomycin were observed. In 28 out of 40 followed-up patients changes were found in the form of sinus tachycardia, in 3 of them rhythm changes were observed in the form of extra systols, in 6 low segment S-T, in 12 changes of T waves (lower or isoelectric in 5, negative in 3, and high, pointed in 4 patients). In one patient there was found more prominent right axial deviation and the appearance of small Q in the site not seen before. In addition ot ECG, blood pictue and electrolytes were examined. Parallel occurence of anaemia and sinus tachycaria were found, while electrolytes mostly remained in normal limits. More significant and multiple changes were found in one patient, most often when the administration of a drug was followed by ECG. Lack of appearance of ECG changes in a certain number of our patinets most probably resulted from undue recording, and not from the harmful effect of a drug.


[Substitution therapy in the treatment of acute leukoses].

In the treatment of acute leukoses, from the first onset of the disease till the occurrence of the first remission, as well as in the course of intesive hemiotherapy, the substitution therapy by blood derivatives has the great importance. Anaemia, granulocytopenia, hypoproteinaemia and hemorrhagic syndroms, caused by thrombocytopenia, liver diseases and disseminated intravascular coagulation, are the most frequent disorders requiring the substitution therapy. Authors presented the advantages of the substitution  therapy by blood derivatives upon the whole blood.


[Results in the use of blood components separated by cytophoresis in leukemia treated with cytostatics (our 1st experiences with flowing-effect centrifuge)].

Since the essence of the malign process is still unknown, together with the basic causal principle (or principles?) of the pathological, malign growth, we, are not in position to apply the adequate, the only correct causal therapy with leukosis. As a consequence, we have numberous therapeutical diagrams with leukosis. As a consequence, we have numerous therapeutical diagrams in which there is adomination of pharmacological substances having cytostatic effects of anti-microbal, substitutional and symptomatical therapies. Cytostatics represent an expressedly different therapy. Various, very powerful cytostatic combinations and procedures applied with a desire to bring the patient into remission often cause the therapeutist to have another, very important problem: how to prevent the haematological complications using the cytostatic therapy, primarily the leukopenia and thrombocytopenia which, in bodies damaged by malign processes, can cause difficult complications. In order to avoid these, a series of new methods have been developed within the cytophoresis and haemotherapy. With the advent of separators of blood components it seems that the problem of selective and precise haemotherapy has been solved completely. Namely, if the components are applied precisely, in the stage when the patient lacks them in the desired concentration, the possibility of manifold therapeutical applications offer a possibility for an adequate subtitutional therapy. This paper brings forward our initial results from this field. The CENTRIFUGE-- AMINCO was used for seperation. The seperation in it takes place in a closed system (infection impossible), and thanks to special construction which simulates the internal medium of blood vessels, the mechanical decay of tangible components in the extracorporal medium has been reduced to a minimum. By means of adjustment of peristaltic pumps, the desired seperation is possible to be achieved. Concentrated components obtained by means of separation (leukocytes and thrombocytes, separated or together), have been applied with patients having leukosis once or several times, in the stage when they, due to cytostatic treatment, had very low values of these components with the existing or threatening complications. The substitional therapy has been applied with 14 patients and very efficient effects have been observed.


Hydroxylation of p-coumaric acid by horseradish peroxidase. The role of superoxide and hydroxyl radicals.

1. In the presence of dihydroxyfumarate, horseradish peroxidase catalyses the conversion of p-coumaric acid into caffeic acid at pH 6. This hydroxylation is completely inhibited by superoxide dismutase. 2. Dihydroxyfumarate cannot be replaced by ascorbate H2O2, NADH, cysteine or sulphite. Peroxidase can be replaced by high (10 mM) concentrations of FeSO4, but this reaction is almost unaffected by superoxide dismutase. 3. Hydroxylation by the peroxidase/dihydroxyfumarate system is completely inhibited by low concentrations of Mn2+ or Cu2+. It is proposed that this is due to the ability of these metal ions to react with the superoxide radical O2--. 4. Hydroxylation is partially inhibited by mannitol, Tris or ethanol and completely inhibited by formate. This seems to be due to the ability of these reagents to react with the hydroxyl radical -OH. 5. It is concluded that O2-- is generated during the oxidation of dihydroxyfumarate by peroxidase and reacts with H2O2 to produce hydroxyl radicals, which then convert p-coumaric acid into caffeic acid.


Metal-replacement studies in Bacillus stearothermophilus aldolase and a comparison of the mechanisms of class I and class II aldolases.

A comparison of the product-inhibition patterns during cleavage of D-fructose 1,6-diphosphate by aldolases from yeast, rabbit muscle and Bacillus stearothermophilus shows an ordered reaction sequence for all three enzymes, with dihydroxyacetone phosphate the last-leaving product. Addition of Zn2+, Co2+, Fe2+, Mn2+ or Cd2+ ions to the inactive apo-(Bacillus stearothermophilus aldolase) restores activity to different extents, whereas Ni2+, Mg2+ or Cu2+ ions have no effect. The cleavage activity of this aldolase is not enhanced by added K+ ion. The effects of metal replacement on thermal stability, Km and Vmax. are given and the possible role of the metal is discussed in the light of these results.


Isolation of S-adenosyl-3-thiopropylamine from the eye of the sea catfish (Arius felis).

A method is reported for the separation of S-adenosyl-3-methylthiopropylamine and other basic compounds in the eye of the sea catfish (Arius felis) by ion-exchange chromatography on CM-Sephadex. One of the basic compounds was isolated in crystalline form and was shown to be S-adenosyl-3-thiopropylamine by chemical and spectroscopic characterizations and by comparison with a synthetic sample.


The anomalous kinetics of coupled aspartate aminotransferase and malate dehydrogenase. Evidence for compartmentation of oxaloacetate.

Cytoplasmic aspartate aminotransferase and malate dehydrogenase were purified from pig heart. Kinetic parameters were determined for the separate reaction catalysed by each enzyme and used to predict the course of the coupled reaction: (see article). Although a lag phase should have been easily seen, none was detected. The same coupled reaction was also carried out by using radioactive aspartate in the presence of unlabelled oxaloacetate. The reaction was quenched with HClO4 after 70 ms and the specific radioactivity of the malate produced in this system was found to be essentially the same as that of the original aspartate. These results show that oxaloacetate produced by the aspartate aminotransferase is converted into malate by malate dehydrogenase before it equilibrates with the pool of unlabelled oxaloacetate and are consistent with a proposal that the enzymes are associated in a complex. However, no physical evidence of the existence of a complex could be found. An alternative means of compartmentation of the intermediate as an unstable isomer is considered.


Characterization of the extracellular haemoglobin of Haemopsis sanguisuga (L.).

The haemoglobin from the blood of the horseleech, Haemopsis sanguisuga (L.), had a sedimentation coefficient, SO20, w, of 59.11 +/- 0.55 S, and a molecular weight as determined by sedimentation equilibrium of 3.71 X 10(6)+/-9904 X 10(6). In the electron microscope the molecule appeared to be made up of two hexagonal plates, as is found with other worm haemoglobins, with dimensions 24.4+/-2.0 nm (across the hexagon) and 15.2+/-1.4 nm (height). The amino acid composition and spectrum were closely similar to those of the haemoglobins of other annelids (e.g. Lumbricus). The alpha-helical content, calculated from circular-dichroism measurements in the far-u.v. region, was 56-63%. The haem content was 2.49%, corresponding to a minimum molecular weight per haem group of 24 800, but detergent-gel electrophoresis indicated the presence of polypeptide chains of mol.wts. 12 600, 14 800, 15 500 and 25 100. The pH-induced dissociation of the native molecule yielded compotosol of Soya-bean root nodules.


Physical and catalytic properties of alpha-amylase from Tenebrio molitor L. larvae.

The amylase from Tenebrio molitor L. larvae (yellow mealworm) was characterized according to a number of its molecular and catalytic properties. The insect amylase is a single polypeptide chain with mol.wt. 68000, an isoelectric point of 4.0 and a very low content of sulphur-containing amino acids. The enzyme is a Ca2+-protein and behaves as an alpha-amylase. Removal of Ca2+ by exhaustive dialysis against water causes the irreversible inactivation of the enzyme. Moreover, the enzyme is activated by the presence in the assay mixture of Cl-, or some other inorganic anions that are less effective than Cl-, and is inhibited by F-. Optimal conditions of pH and temperature for the enzymic activity are 5.8 and 37 degrees C. The insect amylase exhibits an identical kinetic behaviour toward starch, amylose and amylopectin; the enzyme hydrolyses glycogen with a higher affinity constant. Compared with the non-insect alpha-amylases described in the literature, Tenebrio molitor amylase has a lower affinity for starch.


The unreliability of estimates of group dissociation constants.

If a molecule contains two groups that bind a common ligand, then to determine their group dissociation constants it is necessary (1) to assume that some property of the molecule is affected by the degree of ligation of only one of the groups, and (2) to determine how this property varies with the concentration of free ligand. When assignment of group dissociation constants made on this basis suggests that the degree of ligation of each group greatly affects the dissociation constant of the other, then the original assumption that the chosen property is completely unaffected by ligation of the second group is rendered doubtful. Dissociation constants of interacting groups can therefore not be reliably determined.


Formation of monoferric ovotransferrins in the presence of chelates.

1. When ovotransferrin is partially saturated with iron, endotherms for apo-ovotransferrin, two monoferric ovotransferrins and Fe2-ovotransferrin are observed by differential scanning calorimetry. The relative sizes of the endotherms are changed in the presence of the iron-chelating agents nitrilotriacetic acid and ATP. 2. When iron is added as Fe(III)-nitrilotriacetate, at Fe-nitrilotriacetate: ovotransferrin ratios less than unity, the endotherm for Fe2-ovotransferrin is essentially absent. At Fe-nitrilotriacetate: ovotransferrin ratios of unity the only species present in solution in appreciable concentration as evidenced by their differential-scanning-calorimetry endotherms, are two monoferric ovotransferrins in approximately equal amounts. At Fe-nitrilotriacetate: ovotransferrin ratios greater than unity, the apo-ovotransferrin endotherm is absent, and the endotherms for the two monoferric ovotransferrins decrease in size as the endotherm for Fe2-ovotransferrin increases. 3. In the presence of nitrilotriacetate, binding of iron to the two sites of ovotransferrin is highly anti-co-operative, but essentially indiscriminate. When monoferric ovotransferrin is formed from apo-ovotransferrin, binding at one site is slightly favoured compared with binding at the other site, but once iron has been bound at either site, the binding affinity for iron at the unoccupied site is much decreased.


Chemical and physical properties of the human urinary glycoprotein with gastric antisecretory activity.

The chemical and physical properties of the high-molecular-weight glycoprotein (SO20, w = 8S; Ve=Vo on Sephadex G-200) with gastric antisecretory activity extracted from the urine of pregnant women were studied. Gel filtration in the presence of sodium dodecyl sulphate and sodium dodecyl sulphate/polyacrylamide-disc-gel electrophoresis indicated subunit mol.wts. of 16 000 +/- 1500 and 13 000 +/- 1000 respectively. Reaggregation of the subunits and partial recovery of the biological activity were observed on removal of the detergent. The partial C-terminal sequence was found to be Phe-Tyr-Leu-Val-OH, whereas glycine appears to be the N-terminal amino acid. The carbohydrate composition was examined; all galactosamine was found to be O-glycosidically linked to the polypeptide chain.


The whey proteins of the milk of red deer (Cervus elaphus L.). A homologue of bovine beta-lactoglobulin.

1. The whey proteins from the milk of red deer are compared with those of cattle. Gel chromatography and electrophoresis showed a close similarity between the whey proteins of the two species in the size, mobility and relative amounts of the main constituents and in the changes in their relative amounts with time after parturition. 2. The major constituent of the deer whey was isolated. It appeared to be homologous with bovine beta-lactoglobulin and had the following properties: m=-5.2X10(-9)m2-s-1-V-1 at 4 degrees C and pH 8.6; pI=5.17; S020, w =2.89S; v=0.748 ml/g; E1g/dl 1cm= 9.12 at 278 nm; deltan/c=1.794 X 10(-3)dl/g at 579 nm (all at 20 degrees C except m). Its molecular weight was that of a dimer with a subunit weight of 18 000. 3. Amino acid analyses of this protein, adjusted to lysine = 15 residues showed that it contains one more residue of aspartic acid, alanine and methionine and one less glutamic acid residue and two less leucine residues than bovine beta-lactoglobulin A. 4. On starch-gel electrophoresis at pH 8.2, this protein migrated at the same rate as bovine beta-lactoglobulin B, although its isoelectric point is close to that of the bovine A variant. Milk from three out of 27 hinds examined showed a variant. This migrated in starch gel at the same rate as the bovine A variant but had a more acid pI = 5.02. 5. The two species whose milk whey proteins are compared represent two different families of ruminants. The similarities found support the view that the milk whey proteins of the bovids are probably typical of the suborder as a whole.


Mass-spectrometric identification and sequence location of the ten residues of the new amino acid (gamma-Carboxyglutamic acid) in the N-terminal region of prothrombin.

The detailed mass-spectrometric evidence for our original findings [Magnusson et al. (1974) FEBS Lett. 44, 189-193] of ten gamma-carboxyglutamic acid residues in the N-terminal calcium-binding polypeptide of prothrombin is presented. The identification and sequence location of gamma-carboxyglutamic acid was made by electron-impact and field-desorption studies on acetyl permethyl peptide derivatives, and on the free amino acid. Details of the derivatives formed, and how this new amino acid may be easily recognized and sequenced from the mass spectrum, are given as a basis for future work.


The interaction between Beta-lactoglobulin and sodium N-dodecyl sulphate.

1. The binding of sodium n-dodecyl sulphate to beta-lactoglobulin was studied in the pH range 3.5-7.0 by equilibrium dialysis, ultracentrifugation and microcalorimetry. 2. At low binding concentrations (less than 30 bound surfactants anions per protein molecule) the complexes formed aggregates in solution. 3. At higher binding concentrations aggregation does not occur at low ionic strength (0.01 mol/litre), but continues at high ionic strength (0.1 mol/litre). 4. At 25 degrees C the enthalpy of interaction of sodium n-dodecyl sulphate with beta-lactoglobulin can be interpreted as the sum of the enthalpies of formation of a complex with 2 bound surfactant anions, with an enthalpy change of -9.5 kJ-mol-1 of bound surfactant, and complexes containing at least 22 bound surfactant anions, with limiting enthalpies per bound surfactant anion of -12.4 kJ-mol-1 at pH 3.5 and -3.25 kJ-mol-1 at pH 5.5. 5. The binding of surfactant and the enthalpy of interaction at pH 3.5 ARE NOT SIGNIFICANTLY AFFECTED BY THE ADDITION Of 8 M-urea. 6. The data indicate that at low binding concentrations the interaction is of an ionic nature, and is accompanied by a conformational change in the protein.


The occurrence in amino acid sequences of extensive informational symmetries based on possible codon-codon complementarity in the encoding polynucleotides.

1. A procedure is described for the detection and assessment of informational complementarity in an amino acid sequence; it is based on possible autocomplementarity in the mRNA, and involves codon-to-codon matching. 2. This procedure was applied to myelin basic protein, a variety of protamines, histone IV, silk fibroin, rat skin collagen alpha1 chain and a sheep keratin. A multiplicity of extensive low-probability informational symmetries, based on codon-to-codon matching, were detected. 3. These low-probability orderings, which are independent of the actual mRNA codons, are rationalized in terms of the evolutionary ordering of the amino acid sequences concerned, in such a way that constraints on the secondary structure of the coding polynucleotides were satisfied. This possible interpretation is supported by a number of significant common properties of the protein sequences analysed.


Modified methods of dialysis.

Dialysis modifications are described that are based on the use of a novel rotating dialysis bottle in one- or two-solvent systems. Advantages include complete mixing and rapid equilibrium of diffusing substances, favourable volume changes, economy of solvent and more effective removal of diffusible materials.


The effect of detergents on bovine adrenal ferredoxin.

The incubation of adrenal ferredoxin with various detergents in the presence of oxygen or ferricyanide leads to bleaching of the protein. The bleached preparation has the properties of apoferredoxin and it can be reconstituted with high yield by conventional methods.


The prediction of the conformation of membrane proteins from the sequence of amino acids.

The methods of Chou & Fasman [Biochemistry (1974) 13, 211-222, 222-245] and of Lim [J. Mol. Biol. (1974)88, 857-872, 873-894] for predicting secondary structure from amino acid sequence have been applied to five predominantly helical membrane-associated peptides. The predictions from the method of Lim (1974a,b) are consistent with the experimental observations, whereas those from Chou & Fasman (1974a,b), although not inconsistent with alpha-helix, favour a beta-structure for several very hydrophobic regions. The results may be rationalized in terms of the effect of the solvent on the conformation of a polypeptide.


Chromatin-bound and free forms of poly(adenylic acid) polymerase in rat hepatic nuclei.

Isolated rat hepatic nuclei were shown to contain poly(A) polymerase in two distinct physiologically active forms. One form was associated with the chromatin fraction and was dependent on endogenous RNA, presumably mRNA. The other activity was localized in the nuclear sap in a 'free' form and was stimulated almost 30-40-fold by exogenously added poly(A). Isolated nucleoli were devoid of significant poly(A)-synthesizing activity.


Inactivation of cathepsin D by dithiophosgene and by 2,2-dichloro-1,3-dithiacyclobutanone.

Cathepsin D, purified from bovine spleen, is inactivated by the unstable inhibitors dithiophosgene and 2,2-dichloro-1,3-dithiacyclobutanone. Inhibition constants are identical for both of the compounds tested: Ki 96.1 muM;k/c0.406. It appears that the active species is 2,2-dichloro-1,3-dithiacyclobutanone, to which dithiophosgene is hydrolysed before cathepsin D inactivation.


Isolation of the liver N-aspartyl-beta-glucosaminidase in aspartylglucosaminuria.

The isolation of liver N-aspartyl-beta-glucosaminidase in human aspartylglucosaminuria, where this enzyme activity is diminished, yields an enzyme molecule with the same molecular weight and pH optimum as the normal enzyme. Its activity is 10% of that of the control preparation. Combination of both enzymes results in the summation of both activities, and the pathological enzyme does not inhibit the control preparation. It is concluded that no change into a totally different isoenzyme has occurred in aspartylglucosaminuria.


Microbiological degradation of bile acids. The preparation of some hypothetical metabolites involved in cholic acid degradation.

1. To identify the intermediates involved in the degradation of cholic acid, the further degradation of (4R)-4-[4alpha-(2-carboxyethyl)-3aalpha-hexahydro-7abeta-methyl-5-oxoindan-1beta-yl]valeric acid (IVa) by Arthrobacter simplex was attempted. The organism could not utilize this acid but some hypothetical intermediate metabolities of compound (IVa) were prepared for later use as reference compounds. 2. The nor homologue (IIIa) and the dinor homologue (IIIb) of compound (IVa) were prepared by exposure of 3-oxo-24-nor-5beta-cholan-23-oic acid (I) and (20S)-3beta-hydroxy-5-pregnene-20-carboxylic acid (II) to A. simplex respectively. These compounds correspond to the respective metabolites produced by the shortening of the valeric acid side chain of compound (IVa) in a manner analogous to the conventional fatty acid alpha- and beta-oxidation mechanisms. Their structures were confirmed by partial synthesis. 3. The following authentic samples of reduction products of the oxodicarboxylic acids (IIIa), (IIIb) and (IVa) were also synthesized as hypothetical metabolities: (4R)-4-[3aalpha-hexahydro-5alpha-hydroxy-4alpha-(3-hydroxypropyl)-7abeta-methylindan-1beta-yl]valeric acid (Vb) and its nor homologue (VIIa) and dinor homologue (IXa);(4R)-4-[3Aaalpha-hexahydro-5alpha-hydroxy-4alpha-(3-hydroxypropyl)-7abeta-methylindan-1beta-yl]-pentan-1-ol (Vc); and their respective 5beta epimers (Ve), (VIIc), (IXc) and (Vf). 4. In connexion with the non-utilization of compound (IVa) by A. simplex, the possibility that not all the metabolites formed from cholic acid by a certain micro-organism can be utilized by the same organism is considered.


Sodium/proton antiport in brush-border-membrane vesicles isolated from rat small intestine and kidney.

Studies on proton and Na+ transport by isolated intestinal and renal brush-border-membrane vesicles were carried out to test for the presence of an Na+/H+-exchange system. Proton transport was evaluated as proton transfer from the intravesicular space to the incubation medium by monitoring pH changes in the membrane suspension induced by sudden addition of cations. Na+ transport was determined as Na+ uptake into the vesicles by filtration technique. A sudden addition of sodium salts (but not choline) to the membrane suspension provokes an acidification of the incubation medium which is abolished by the addition of 0.5% Triton X-100. Pretreatment of the membranes with Triton X-100 prevents the acidification. The acidification is also not observed if the [K+] and proton conductance of the membranes have been increased by the simultaneous addition of valinomycin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone to the K+-rich incubation medium. Either valinomycin or carbonyl cyanide p-trifluoromethoxyphenylhydrazone when added alone do not alter the response of the membranes to the addition of Na+. Na+ uptake by brush-border microvilli is enhanced in the presence of a proton gradient directed from the intravesicular space to the incubation medium. Under these conditions a transient accumulation of Na+ inside the vesicles is observed. It is concluded that intestinal and renal brush-border membranes contain a NA+/H+ antiport system which catalyses an electroneutral exchange of Na+ against protons and consequently can produce a proton gradient in the presence of a concentration difference for Na+. This system might be involved in the active proton secretion of the small intestine and the proximal tubule of the kidney.


Stimulation of hepatic biogenesis of sterols on administration of adenosine compounds.

1. Re-feeding starved rats increased the biogenesis of sterols in livers, with highest activity at 6h after the start of food intake. 2. Complete deficiency of protein or fat and partial deficiency of carbohydrate in the diet had no effect on sterol biogenesis. 3. Glucose, citrate or pyruvate, when administered intraperitoneally to starved rats, stimulated the biogenesis of sterols only at high concentrations. 4. ATP given intraperitoneally at low concentrations (10mg/rat) stimulated biogenesis of sterols, but not of fatty acids, from [1-14C]acetate. This effect was also obtained with other adenosine compounds, but not with adenine or guanosine. 5. Administration of adenosine compounds to starved rats also increased the incorporation of [1-14C]acetate into sterols in liver slices and also the activity of microsomal 3-hydroxy-3-methylglutaryl-CoA reductase. The results suggest a regulatory role for adenosine compounds in the hepatic biogenesis of isoprenoid compounds.


The concentration of glycine by preparations of the yeast Saccharomyces Carlsbergensis depleted of adenosine triphosphate: Effects of proton gradients and uncoupling agents.

1. At pH 4.5 and 30degreesC, yeast preparations depleted of ATP in the presence of antimycin and deoxyglucose spontaneously lost K+, gaining roughly an equivalent amount of H+. 2. Five proton conductors including azide and 2,4-dinitrophenol accelerated this process, as did [14C]glycine, which was absorbed with two extra equivalents of H+. 3. The rate of glycine uptake at pH 4.5 diminished fourfold when cellular K+ fell by 20%. 4. The distribution of [14C]propionate indicated that the intracellular pH fell from 6.2 to 5.7 when the cellular content of K+ fell by 30%. 5. Glycine uptake from a 5 muM solution was about 400 times faster at pH 4.5 than it was at pH 7.4 with 100mM-KC1 present ostensibly to lower the membrane potential. 6. Yeast preparations containing 2mM-[14C]glycine absorbed a further amount from a 0.1 muM solution at pH 4.5. After about 10 min a net movement of [14C]glycine out of the yeast occurred. The ratio of the cellular [14Ia1glycine concentration to the concentration outside the yeast reached 4 X 10(4) in these assays, whereas at pH 7.4 in the presence of 100mM-KC1 it did not exceed 15 in 3h. Dimitrophenol lowered the accumulation ratio at pH 4.5, apparently by causing proton conduction. 7. The observations are consistent with the notion that glycine uptake is driven by a proton symport mechanism. 8. Possible factors governing the strikingly low rate of glycine efflux as opposed to its optimum rate of influx are discussed.


Effects of ketone bodies on amino acid metabolism in isolated rat diaphragm.

1. Diaphragms from 48h-starved rats were incubated in Krebs-Ringer bicarbonate medium at 37degreesC for 30min and then transferred into new medium and incubated for 1, 2 and 3 h. 2. The amount of free amino acids found at the end of each time of incubation was larger than the amount at the beginning of incubation, indicating that in this system proteolysis is prevailing. 3. The diaphragms was releasing mainly alanine and glutamine into the incubation medium. 4. Within the periods of incubation the release and metabolism of free amino acids was proceeding at a constant rate. 5. Addition of sodium DL-3-hydroxybutyrate decreased the tissue content of several amino acids, among which were tyrosine and phenylalanine, suggesting that proteolysis was decreased by ketone bodies. 6. In the presence of glucose (10mM) and branched-chain amino acids (0.5mM), sodium DL-3-hydroxybutyrate at concentrations of 4 or 6 mM resulted in 30% decrease in tissue alanine content and a 20% decline in alanine release. Release of taurine and glutamine was decreased by 19 and 16% respectively with 6 mM-sodium DL-3-hydroxybutyrate. Addition of sodium acetoacetate (1-3mM) also resulted in a 20-35% decrease in tissue content of alanine, glutamine and taurine and in a 15-24% decrease of alanine and glutamine release. Smaller decreases (less than 15%) in the release of glycine, threonine, proline, serine and aspartate were also observed in the presence of sodium DL-3-hydroxybutyrate or sodium acetoacetate. 7. Substitution of pyruvate (1.0mM) for glucose in the presence of acetoacetate restored alanine and glutamine production to control values. In the presence of acetoacetate, pyruvate also increased the tissue content of aspartate by 77% and decreased the tissue content of glutamate by 30%. 8. It is suggested that in diaphragms from starved rats, ketone bodies (a) in the absence of other substrates inhibit protein catabolism and (b) in the presence of glucose and branched-chain amino acids decrease alanine and glutamine production, by inhibiting glycolysis.


Inactivation of phosphoenolypyruvate carboxykinase (GTP) by liver extracts.

1. The inactivation of phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) in liver extracts was catalysed by the microsomal fraction, and led to the enzyme becoming bound to the microsomal membranes. 2. Inactivation by microsomal fraction, typsin or heating at 48degreesC was accelerated by L-cystine, D-cystine and oxidized glutathione and decreased by dithiothreitol. 3. MnC1(2) and CoC1(2) protected the enzyme from inactivation by heat or microsomal fraction, but did not affect the inactivation caused by trypsin. 4. Several proteinase inhibitors had no effect on the microsomal inactivation reaction, suggesting that proteolysis was not involved. 5. It is argued that the initial step in the degradation of phosphoenolpyruvate carboxykinase (GTP) is an inactivation reaction, perhaps involving oxidized thiol compounds.


Studies on the proteins from the seeds of Croton tiglium and of Jatropha curcas. Toxic properties and inhibition of protein synthesis in vitro.

1. Proteins extracted from the seeds of the Euphorbiaceae croton tiglium and Jatropha curcas were separated into three major peaks (I,II,and III) by Sephadex chromatography. 2. The crude protein from both seeds and peaks I and II from Croton and peak I from Jatropha were toxic to mice, to different extents. 3. The crude protein and peak I and peak II from both seeds, inhibited protein synthesis by a reticulocyte lysate; maximum inhibition was exerted by peak II from both seeds. None of these preparations affected protein synthesis in vitro by Ehrlich ascites cells.


Lipid composition of lymphocyte plasma membrane from pig mesenteric lymph node.

1. The lipid fraction of the plasma membrane of pig mesenteric lymph-node lymphocytes contained primarily (94%) neutral lipids and phospholipids in about equal weights. The remianing lipid comprised glycosphingolipids (1.8%), gangliosides (o.27%)and probably ceramides (1.3%). The major phospholipid was phosphatidylcholine (46% of the total), and mono- and tri-hexosylceramides accounted for 72% of the glycosphingolipids. Haematoside was distributed between the glycosphingolipid and ganglioside fractions. The major ganglioside was monosialoganglioside. About 90% of the sialic acid was N-glycollylated. 2. A comparision of the lipid composition of the plasma-membrane fraction with that of the initial lymph-node homogenate showed that the purified membrane contained increased proportions of phospholipids, especially sphingomyelin, glycosphingolipids and gangliosides. 3. Fatty acid analyses showed that the membrane phosphatidylcholine was rich in palmitic acid, that the sphingomeyelin and phosphatidylethanolamine were high in myristic acid and that the glycosphingolipids were rich in oleic acid.


Effects of pronase and neuraminidase treatment on a myelin-associated glycoprotein in developing brain.

Rats (14 days old) were injected with [14c]fucose and young adult rats with [3H]fucose in order to label the myelin-associated glycoproteins. As previously reported, the major [14C]fucose-labelled glycoprotein in the immature myelin had a higher apparent molecular weight on sodium dodecyl sulphate/polyacrylamide gels that the [3H]fucose-labelled glycoprotein in mature myelin. This predominant doubly labelled glycoprotein component was partially purified by preparative gel electrophoresis and converted to glycopeptides by extensive Pronase digestion. Gel filtration on Sephadex G-50 separated the glycopeptides into several clases, which were designted A,B, C AND D, from high to low molecular weight. The 14C-labelled glycopeptides from immature myeline were enriched in the highest-molecular-weight class A relative to the 3H-labelled glycopeptides from mature myelin. Neuraminidase treatment of the glycoprotein before Pronase digestion greatly decreased the proportion of glycopeptides fractionating in the higher-molecular-weight classes and largely eliminated the developmental differences that were apparent by gel filtration. However, neuraminidase treatment did not decrease the magnitude of the developmental difference revealed by electrophoresing the intact glycoprotein on sodium dodecyl sulphate gels, although it did decrease the apparent molecular weight of the glycoprotein from both the 15-day-old and adult rats by an amount comparable in magnitude to that  developmental difference. The results from gel filtration of glycopeptides indicate that there is a higher content of large molecular weight, sialic acid-rich oligosaccharide units in the glycoprotein of immature myelin. However, the higher apparent molecular weight for the glycoprotein from 15-day-old rats on sodium dodcyl sulphate gels is not due primarily to its higher sialic acid content.


Regulation of mammalian protein synthesis in vivo. Protein synthesis in rat liver and kidney after the administration of sublethal doses of cyclohyximide.

Protein synthesis in vivo was studied at various times after the administration of sublethal doses of cycloheximide to rats. Cycloheximide caused an inhibition, followed by a dose-and time-dependent stimulation, of incorportation of labelled precursor into proteins of the liver and kidney. The stimulation of protein synthesis at 24h was not due to a change of precursor  pool or the specific radioactivity of the precursor used. During the stimulatory period, leucine incorporation into various cellular protein fractions varied; incorporation into total nuclear protein was the most affected.


Rates of induction of mitochondrial aldehyde dehydrogenase in rat liver.

Aldehyde dehydrogenase activities in liver mitochondria isolated from rats given ethanol at hourly intervals by gastric intubation showed a brief lag period followed by a rapid increase in specific activities until a maximum was attained at about 3h.


The mechanism of the inhibition of the mitochondrial pyruvate transportater by alpha-cyanocinnamate derivatives.

Pyruvate transport into rat liver mitochondria is inhibited by a variety of thiol reagents. alpha-Cyanocinnamate and its derivates, potent and reversible inhibitors of pyruvate transport, react reversibly with mercaptoethanol and cysteine to form addition products. It is concluded that these inhibitors react with an essential thiol group on the pyruvate carrier.


Compartmentation of albumin and ferritin synthesis in rat liver in vivo.

Infusion of rats with [U-14C]glycine resulted in labelling of glycine and serine in plasma albumin and liver ferritin. The patterms of labelling in these two proteins were not similar, suggesting that each is synthesized from a different pool of free amino acids.


Quantitative analysis of metabolism of hepatic triglyceride in ethanol-treated rats.

An acute intraperitoneal injection of ethanol (0.7 or 2.1g/kg body wt.) causes the reversible, dose-dependent accumulation of hepatic triglyceride in rats. By using a pulse of [14C]palmitate injected into a tail vein, it was found that ethanol (2.1g/kg)had no effect on the flux of unesterified fatty acid of serum (4.3mumol/min per 100g body wt.). However, either dose increased the fraction of the total flux going to liver from 0.16 to0.27 as rapidly as could be measured (30s), and it remained elevated until all ethanol had been cleared from the blood. The fraction of the total radioactivity in lipids of liver that was in triglyceride increased linearly for 1 h from 30 to 50% and there was a simultaneous decrease in phospholipid from 60 to 40%. The rate of synthesis of hepatic triglyceride derived directly from unesterified fatty acid of serum was calculated by using the flux rate of unesterified fatty acid in serum, the fractional hepatic uptake of this flux, and the percentage of liver fatty acid esterified to triglyceride. This contribution is related to the total synthetic rate of hepatic triglyceride (rate of accumulation+rate of release) to determine quantitatively how much of the developing fatty liver is attributable to increased uptake of unesterfied fatty acid of serum. At the higher dose of ethanol, about half of the accumulating triglyceride is derived from this source, whereas with the lower dose of ethanol it can account for all of the build-up.


Mechanism of increased hepatic uptake of unesterified fatty acid from serum of ethanol-treated rats.

Studies were made on the mechanism by which livers of ethanol-treated rats take up an increased fraction of the total flux of unesterified fatty acid in serum. It was found that ethanol (0.7g/kg) causes a twofold rise in the serum content of liver, and that this serum is in rapid equilibrium with the general circulation. The fractional hepatic uptake from serum of group of compounds with varying uptake mechanisms and metabolic fates was studied in control and ethanol-treated animals. All the compounds tested, including unesterified fatty acid, showed an enhanced uptake when ethanol was given. For one of the compounds, carbon tetrachloride, a dose/response relationship was established between the amount administered, the amount taken up by liver, and the amount metabolized. These findings were interpreted to mean that this dose of ethanol causes the liver to receive an increased flow of blood, and as a result all compounds present and capable of being taken by liver are taken up at an increased rate. Hepatic blood flow was measured by a technique that monitors the rate of clearance of a colloidal lipid emulsion. It was found that ethanol increased hepatic blood flow by about 60%. This effect of ethanol on hepatic blood flow provides an explanation for the fatty liver and the synergistic effect between an acute dose of ethanol and carbon tetrachloride. A hypothesis to explain why a moderate dose of ethanol causes triglyceride to accumulate in liver is presented.


Effect of oestradiol-17beta and progesterone on the metabolism of [1,2(-3)H] progesterone by the rabbit endometrium and myometrium.

The metabolism of [3H]progesterone in the rabbit endometrium and myometrium was studied in vitro. The major metabolities identified were 5alpha-pregnane-3,20-dione, 20alpha-hydroxypregn-4-en-3-one, 3beta-hydroxy-5alpha-preganan-20-one and 5alpha-pregnane-3beta,20alpha-diol. Other minor metabolites tentatively identified were 3alpha-hydroxy-5beta-pregnan-20-one,20alpha-hydroxy-5beta-pregnan-3-one and 5beta-pregnane-3alpha,20alpha-diol. The ability of the endometrium to metabolize progesterone on a unit weight bais was about 2.7 times that of the myometrium. The metabolism of [3H]progesterone in the rabbit uterus under the influnce of oestradiol-17beta and progesterone was studied. The ability of the oestradiol-treated rabbit uterus to metabolize progesterone was increased to 3.47 times that of the overiectomized control uterus, whereas the oestradiol-progesterone-treated rabbit uterus metabolized only 1.86 times that of the control. Study of the metabolism of progesterone with uterine subcellular preparations revealed that the 5alpha-reductase enzyme was present mainly in the nuclear fraction; 20alpha-hydroxysteroid dehydrogenase was found in the cytosol fraction and 3beta-hydroxysteroid dehydrogenase in the particulate fraction of the uterus. The metabolic pathways of progesterone in the rabbit uterine tissue are discussed.


Inhibition of protein synthesis in vitro by crotins and ricin. Effect on the steps of peptide chain elongation.

The effects of crotin I and crotin II on the partial reactions of polypeptide chain elongation were investigated and compared with the known effects of ricin. Crotin II was a more powerful inhibitor than crotin I, but no qualitative differences between the two crotins were found. Rat liver ribosomes, preincubated with crotins and washed through sucrose gradients, remained inactive in protein synthesis. Among the individual steps of elongation, the peptidyltransferase reaction was unaffected by crotins, but some of the reactions that involve the interaction of elongation factors 1 and 2 with ribosomes were modified. A strong inhibition of the binding of elongation factor 2 to ribosomes and a stimulation of the elongation factor2-dependent GTP hydrolysis were observed; this indicates the formation of a very unstable elongation factor 2--GDP--ribosome complex, which, however, allows a single round of translocation to take place in the presence ofelongation factor 2 and added GTP. The elongation factor 1-dependent GTP hydrolysis was inhibited by crotins, whereas the enzymic binding of aminoacyl-tRNA, to both rat liver and Artemia salina ribosomes, was scarcely affected. In a protein-synthesizing system the inhibition by crotins and by ricin leads to a block of the nascent peptides on the ribosomal aminoacyl-tRNA site, an effect consistent with inhibition at the level of translocation. The mechanism of action of crotins appears to be very similar to that of ricin.


The effects of denervation on protein turnover of rat skeletal muscle.

The effects of denervation on muscle weight, rates of protein synthesis and breakdown, and RNA concentraitons were studied in the soleus and extensor digitorum longus muscle. Althrough the soleus underwent a true atrophy after section of the sciatic nerve, the extensor digitorum longus continued to grow, albeit at a lower rate than innervated controls. At 24h after nerve section protein breakdown was increased in both muscle types when compared with internal controls, and remained so throughout the 10 days studied. The possibility that this increased catabolism might arise from conformational changes of proteins after denervation was not substantiated, as myofibrillar or soluble proteins of denervated and control tissues were equally susceptible to degradation in vitro by three proteinases. Tyrosine uptake into the denervated extensor digitorum longus was decreased throughout the 10 days studied, whereas two phases of increased transport of the amino acid were found in the soleus. Significant decreases in rates of protein synthesis were found 1 and 2 days after denervation and results are presented that suggest that these changes may result from a decrease in ribosomal involvement in the translation process. These initial decreases were not maintained and the rate of protein synthesis was in fact  increased when compared with controls, at 7 and 10 days. The increased synthetic rates of the 7-day denervated tissues were reflected as proportional increases in both myofibrillar and soluble proteins. It is suggested that the increase in synthesis at this time may result from an increase in both the abailability and active involvement of ribosomes, and that these anabolic trends may be caused by spontaneous fibrillation and/or the amount of passive stretching of the denervated muscles.


Transport of pyruvate nad lactate into human erythrocytes. Evidence for the involvement of the chloride carrier and a chloride-independent carrier.

The kinetics and activation energy of entry of pyruvate and lactate into the erythrocyte were studied at concentrations below 4 and 15mM respectively. The Km and Vmax. values  for both substrates are reported, and it is shown that pyruvate inhibits competitively with respect to lactate and vice versa. In both cases the Km for the carboxylate as a substrate was the same as its Ki as an inhibitor. Alpha-Cyano-4-hydroxycinnamate and its analogues inhibited the uptake of both lactate and pyruvate competitively. Inhibition was also produced by treatment of cells with fluorodinitrobenzene but not with the thiol reagents or Pronase. At high concentrations of pyruvate or lactate (20mM), uptake of the carboxylate was accompanied by an efflux of Cl-ions. This efflux of Cl- was inhibited by alpha-cyano-4-hydroxycinnamate and picrate and could be totally abolished by very low (less than 10 muM) concentrations of the inhibitor of Cl- transport, 4,4'-di-isothiocyanostilbene-2,2'-disulphonic acid. This inhibitor titrated out the chlordie efflux induced by pyruvate, bicarbonate, formate and fluoride, in each case total inhibition becoming apparent when approximately 1.2x10(6) molecules of inhibitor were present per erythrocyte, that is, about one inhibitor molecule per molecule of the Cl- carrier. Evan when Cl- efflux was totally blocked pyruvate and lactate uptake occurred. Kinetic evidence is presented which suggests that the Cl- carrier can transport pyruvate and lactate with a high Km and high Vmax., but that an additional carrier with a low Km and a low Vmax. also exists. This carrier catalyses the exchange of small carboxylate anions with intracellular lactate, is competitively inhibited by alpha-cyano-4-hydroxycinnamate and non-competitively inhibited by picrate. The Cl- carrier shows a reverse pattern of inhibition. It is concluded that net efflux of lactic acid from the cell must occur on the Cl- carrier and involve exchange with HCO3 - followed by loss of CO2. The low Km carrier might be used in pyruvate/lactate or acetoacetate/beta-hydroxybutyrate exchanges involved in transferring reducing power across the cell membrane. The possibility that the Cl- carrier exists in cells other than the erythrocyte is discussed. It is concluded that its presence in other cell membranes together with a low intracellular Cl- concentration would explain why the pH in the cytoplasm is lower than that of the blood, and why permeable carboxylate anions do not accumulate within the cell when added from outside.


Further characterization of rat liver mitochondrial fractions. Lipid composition and synthesis, and protein profiles.

1. Heavy and light mitochondrial fractions obtained by differential centrifugation were further characterized with respect to their lipid composition and synthesis and protein profiles, as seen by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 2. The light mitochondrial fraction was rich in total lipids, phospholipids and cholesterol. The cardiolipin content, however, was low. 3. Rates of [3H]glycerol incorporation into phospholipids of heavy mitochondria and microsomal fractions were almost identical. On the other hand, incorporation into the individual phospholipids in light mitochondria was about 4-6 times higher. Incorporation into cardiolipin of light mitochondria was about 10-fold higher than in the heavy mitochondria. 4. Analysis of protein profiles by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis showed that the pattern obtained for the light mitochondria was similar to that for heavy mitochondria. However, the light fraction was relatively poor in high-molecular-weight proteins and rich in low-molecular-weight proteins. The microsomal protein profile was altogether different. 5. The significance of these findings is discussed in relation to mitochondrial biogenesis.


Effect of ischaemic limb injury on the rates of metabolism of ketone bodies in starved rats.

1. Rats starved for 30h were injected with trace amounts of [3-14C]acetoacetate and beta-hydroxy[3-14C]butyrate 1h after ischaemic limb injury in a 20 degrees C environment, and the concentrations and radioactivities of blood ketone bodies were determined at intervals. 2. Starvation alone raised the rates of production and utilization of beta-hydroxybutyrate plus acetoacetate about 3.7-fold, but lowered their metabolic clearance rates by about 50%. In the starved rat ketone-body oxidation could account for up to 30% of whole body O2 consumption. 3. Injury in starved rats lowered the rates of production and utilization of both beta-hydroxybutyrate and acetoacetate, the combined fall of about 37% slightly exceeding the concomitant fall in whole-body O2 consumption. The concentration of beta-hydroxybutyrate decreased after injury, but its metabolic clearance rate was unaltered; the concentration of acetoacetate rose slightly and its metabolic clearance rate fell.


The androgenic regulation of prostate proteins with a high affinity for deoxyribonucleic acid. Evidence for a prostate deoxyribonucleic acid-unwinding protein.

1. When testosterone is injected into castrated rats in vivo, a significant increase in the incorporation of [35S]methionine into prostate proteins may be detected under conditions in vitro. 2. Studies based on DNA-cellulose chromatography show that the synthesis of prostate proteins with a high affinity for DNA is particularly enhanced by androgenic stimulation. 3. These changes in protein synthesis are negated when the anti-androgen, cyproterone acetate, is administered concomitantly with testosterone in vivo. 4. Two assays were developed for measuring the strand separation of prostate DNA; first, the retention of 3H-labelled native DNA on nitrocellulose membranes, and second, the activation of native DNA as a template for 9S prostate DNA polymerase. On the basis of these criteria, DNA-unwinding activity is present in the prostate gland and it is regulated by androgens in a steroid-and tissue-specific manner. 5. The results are discussed in the context of the mechanism of action of androgens, particularly since the changes provoked in DNA-unwinding activity by androgens precede the onset of DNA replication and mitosis.


Prevention, by ribosome-bound nascent polyphenylalanine chains, of the functional interaction of t-2 toxin with its receptor site.

1. The inhibitory effects of T-2 toxin and trichodermin on poly(U)-directed polyphenylalanine synthesis were studied by using cell-free systems from reticulocytes. Conditions for amino acid incorporation were carefully chosen in an attempt to ensure that the large majority of poly(U) chains bound only one ribosome engaged in protein synthesis and that all such ribosomes carried nascent polyphenylalanine chains containing approximately the same number of residues. 2. Cell-free systems were allowd to synthesize polyphenylalanine, and T-2 toxin and trichodermin were added to the incorporation mixtures at various times. Irrespective of the time of addition, trichodermin (50 mug/ml) inhibited polyphenylalanine synthesis by approx. 70%. In contrast, although T-2 toxin (40 mug/ml), when added at early incubation times, could inhibit polyphenylalanine synthesis with a maximum of 50%, the drug had no effect on the system when added after a critical time-period. 3. It is concluded that although both T-2 toxin and trichodermin can inhibit peptide-bond formation on ribosomes at the level of the peptidyl transferase catalytic centre the presence, on ribosomes, of nascent polyphenylalanine chains above a certain critical chain length excludes T-2 toxin from functional interaction with its receptor site.


Effect of pent-4-enoic acid, propionic acid and other short-chain fatty acids on citrulline synthesis in rat liver mitochondria.

19 The effect of pent-4-enoic acid, propionic acid and several other short-chain fatty acids on citrulline synthesis in rat liver mitochondria was studied. 2.Pent-4-enoate at 1 mM inhibited mitochondrial citulline synthesis by about 80-90%. It is concluded that pent-4-enoate inhibits citrulline synthesis by interfering with some aspect of mitochondrial energy metabolism. This results in impairment of mitochondrial ornithine uptake or depletion of mitochondrial ATP, which, in turn, impairs carbamoyl phosphate synthesis or both. Evidence in support of this conclusion includes: pent-4-enoate has no effect on citrulline synthesis supported by succinate or exogenous ATP; pent-4-enoate lowers the medium plus mitochondrial ATP concentration; finally, when glutamate is the oxidizable substrate, pent-4-enoate decreases the carbamoyl phosphate concentration in mitochondria incubated without ornithine to minimize citrulline synthesis and impairs the mitochondrial uptake of ornithine, but it has neither effect when succinate is the oxidizable substrate. 4. Propionate, butyrate and crotonate also inhibit mitochondrial citrulline synthesis, but much less than pent-4-enoate. 5. Acetate, pentanoate, pent-2-enoate, hexanoate, octanoate, isovalerate, tiglylate and alpha-methylbutyrate have little or no effect on mitochondrial citrulline synthesis.


Glutamate metabolism and transport in rat brain mitochondria.

1. The metabolism and transport of glutamate and glutamine in rat brain mitochondria of non-synaptic origin has been studied in various states. 2. These mitochondria exhibited glutamate uptake and swelling in iso-osmotic ammonium glutamate, both of which were inhibited by N-ethylmaleimide. 3. The oxidation of glutamate was inhibited by 20% by avenaciolide, but glutamine oxidation was not affected. 4. These mitochondria, when metabolizing glutamine, allowed glutamate, but very little aspartate, to efflux at considerable rates. 5. These results suggests that brain mitochondria of non-synaptic origin possess in addition to a relatively rapid glutamate-aspartate translocase, a relatively slow aspartate-independent glutamate-OH-translocase (cf. liver mitochondria).


Synthesis of bile acid monosulphates by the isolated perfused rat kidney.

Perfusion of an isolated rat kidney with labelled bile acids, in a protein-free medium, resulted in the urinary excretion of the labelled bile acid, 3% being converted into polar metabolities in 1h. These metabolities were neither glycine nor taurine conjugates, nor bile acid glucuronides, and on solovolysis yielded the free bile acid. On t.l.c. the metabolite of [24-14C]lithocholic acid had the mobility of lithocholate 3-sulphate. The principal metabolite of [24-14C]chenodeoxycholic acid had the mobility of chenodeoxycholate 7-sulphate; trace amounts appeared as chenodeoxycholate 3-sulphate. [35S]sulphate was incorporated in chenodeoxycholic acid by the kidney, resulting in a similar pattern of sulphation. No disulphate salt of chenodeoxycholic acid was detected. These findings lend support to the hypothesis that renal synthesis may account for some of the bile acid sulphates present in urine in the cholestatic syndrome in man.


Lipid metabolism and mobilization in the guinea pig during pregnancy.

The liver of the foetal guinea pig accumulates a large quantity of triacyglycerol late in gestation at the same time that adipose-tissue mass grows at its maximum rate and foetal adipose-tissue lipoprotein lipase activity and sensitivity to lipolytic hormones has substantially declined. The fatty acid for triacyglycerol synthesis is not synthesized in the foetal liver and it is unlikely that it originates from any of the foetal tissues. Before the accumulation of hepatic triacyglycerol the concentration of free fatty acids increases in both the umbilical vein and the maternal inferior vena cava. This occurs at a time when the triacyglycerol lipase activity in maternal adipose tissue is elevated and the rate of lipolysis, but not of fatty acid esterification, is higher than earlier in gestation or than in the non-pregnant state. It is proposed that the increase in lipolysis in maternal adipose tissue, brought about by an increase in circulating lipolytic hormones, mobilizes fatty acid, which passes to the foetus and is partly stored as hepatic triacylglycerol. The foetal liver effectively removes both long-and short-chain fatty acids from umbilical-vein blood. The rate of placental fatty acid transfer is more than adequate to account for the triacylglycerol accumulation.


Studies on the metabolic role of myo-inositol. Distribution of radioactive myo-inositol in the male rat.

Radioactive myo-inositol was injected intraperitoneally into nephrectomized rats. The radioactive material present in liver, spleen, brain, heart, diaphragm, seminal vesicle, coagulating gland, prostate, epididymis, vas deferens and testis was shown to consist exclusively of myo-inositol and its derivatives, as shown by paper chromatography of hydrolysates and trichloroacetic acid extracts of these tissues. Radioactive myo-inositol was accumulated rapidly within 1 h by the thyroid, coagulating gland and seminal vesicle. Other tissues, such as the pituitary, prostate gland, liver and spleen, concentrated myo-inositol less actively. The muscle tissues studied (diaphragm and heart) concentrated little inositol, whereas brain, testis, and epididymal fat-pad did not concentrate it at all. The lipid fraction of liver contained most of the radio-labelled myo-inositol. In the other organs most of the radioactivity was found in the aqueous trichloroacetic acid extract, largely as free myo-inositol.


Equilibrium-dialysis studies of the interaction between cholic acid and 100000g-supernatant preparations from the rat liver.

1. The binding of cholic acid to 100000g supernatants from rat livers was investigated by equilibrium dialysis and gel-exculsion chromatography. 2. Supernatants were found to contain at least two classes of binding site for cholic acid. 3. These recptor molecules are probably proteins since incubation with proteolytic enzymes resulted in complete loss of cholic acid binding. 4. Supernatants were added to columns of Sephadex G-75, and two groups of fractions were shown to bind cholic acid. One of these contained low-affinity binding sites and the other contained both low- and high-affinity binding sites. 5. Feeding cholestyramine had no effect on cholic acid binding. 6. Increased cholic acid binding occurred after injection of phenobarbitone. There was an increase in the amount of the low-affinity component but no change in the high-affinity component. 7. The dissociation constants of the binding of cholic acid suggest that the binding proteins may be involved in bile acid transport.


Effects of clofibrate on some microsomal hydroxylations involved in the formation and metabolism of bile acids in rat liver.

1. The liver microsomal metabolism of [4-14C]cholesterol, endogenous cholesterol, 7 alpha-hydroxy-4-[6 beta-3H]cholesten-3-one, 5-beta-[7 beta-3H]cholestane-3 alpha, 7 alpha-diol and [3H]lithocholic acid was studdied in control and clofibrate (ethyl p-chlorophenoxyisobutyrate)-treated rats. 2. The extent of 7 alpha-hydroxylation of exogenous [414C]cholesterol and endogenous cholesterol, the latter determined with a mass fragmentographic technique, was the same in the two groups of rats. The extent of 12 alpha-hydroxylation of 7 alpha-hydroxy-4-cholesten-3-one and 5 beta-cholestane-3 alpha, 7 alpha-diol was increased by about 60 and 120% respectively by clofibrate treatment. The 26-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha-diol was not significantly affected by clofibrate. The 6 beta-hydroxylation of lithocholic acid was about 80% higher in the clofibrate-treated animals than in the controls. 3. The results are discussed in the context of present knowledge about the liver microsomal hydroxylating system and bile acid formation in patients with hypercholesterolaemia, treated with clofibrate.


Bacterial catabolism of threonine. Threonine degradation initiated by L-threonine-NAD+ oxidoreductase.

1. Isolates representing seven bacterial genera capable of growth on L-threonine medium, and possessing high L-threonine 3-dehydrogenase activity, were examined to elucidate the catabolic route. 2. The results of growth, manometric and enzymic experiments indicated the catabolism of L-threonine by cleavage to acetyl-CoA plus glycine, the glycine being further metabolized via L-serine to pyruvate, in all cases. No evidence was obtained of a role for aminoacetone in threonine catabolism or for the metabolism of glycine by the glycerate pathway. 3. The properties of a number of key enzymes in L-threonine catabolism were investigated. The inducibly formed L-threonine 3-dehydrogenase, purified from Corynebacterium sp. B6 to a specific activity of about 30-35 mumol of product formed/min per mg of protein, exhibited a sigmoid kinetic response to substrate concentration. The half-saturating concentration of substrate, [S]0.5, was 20mM and the Hill constant (h) was 1.50. The Km for NAD+ was 0.8mM. The properties of the enzyme were studied in cell-free extracts of other bacteria. 4. New assays for 2-amino-3-oxobutyrate-CoA ligase were devised. The Km for CoA was determined for the first time and found to be 0.14mM at pH8, for the enzyme from Corynebacterium sp. B6. Evidence was obtained for the efficient linkage of the dehydrogenase and ligase enzymes. Cell-free extracts all possessed high activities of the inducibly formed ligase. 5. L-Serine hydroxymethyltransferase was formed constitutively by all isolates, whereas formation of the 'glycine-cleavage system' was generally induced by growth on L-threonine or glycine. The coenzyme requirements of both enzymes were established, and their linked activity in the production of L-serine from glycine was demonstrated by using extracts of Corynebacterium sp. B6. 6. L-Serine dehydratase, purified from Corynebacterium sp. B6 to a specific activity of about 4mumol of product formed/min per mg of protein, was found to exhibit sigmoid kinetics with an [S]0.5 of about 20mM and h identical to 1.4. Similar results were obtained with enzyme preparations from all isolates. The enzyme required Mg2+ for maximum activity, was different from the L-threonine dehydratase also detectable in extracts, and was induced by growth on L-threonine or glycine.


The development of the intense circular-dichroic signal during granum formation in greening etiolated maize.

In greening maize mesophyll, circular dichroism (c.d.) revealed the early formation of protein-chlorophyll complexes, followed by unorganized chlorophyll. The intense c.d. [Gregory & Raps (1974) Biochem. J. 142, 193-201] appeared later still, whereas membrane-membrane contact (stacking), measured from electron micrographs, appeared much earlier. Isolated grana, which still showed stacking, lost 92% of their original intense c.d.; intense c.d. is not therefore simply dependent on stacking.


Hip involvement in ankylosing spondylitis.

Hip involvement in ankylosing spondylitis (AS) is a common and disabling problem. The clinical and x-ray records of 87 patients with definite AS (Rome criteria) were examined to define and characterize their hip disease. Clinical hip disease was present in 33 cases (38%), was usually bilateral (91%), and tended to begin early in the disease course; it was the cause of 50% of the Class III and IV disability in the entire study group. Typical findings included regional pain, limitation of motion, muscle atrophy, and flexion contractures. Radiologic hip abnormalities occurred in 42 cases (48%). The radiographic pattern was distinctive when compared to that in two control groups and included axial migration of the femoral head (63%), concentric joint space narrowing (50%), rufflike femoral osteophytosis (36%), and protrusio acetabuli (30%). Eight patients required bilateral hip surgery. Para-articular ossification occurred in 8 of 16 replaced hips; in 5 of 8 hips it caused clinical immobility. This potentially serious complication may limit the usefulness of hip arthroplasty in some AS patients.


Clinical studies of antibodies binding polyriboadenylic acid in systemic lupus erythematosus.

Antibodies of polyriboadenylic acid (poly rA) are demonstrated by filter radioimmunoassay in 75% of patients with systemic lupus erythematosus (SLE), in 54% of patients with discoid lupus erythematosus, and in only 0-7% of normal controls and patients with rheumatoid arthritis or Sjögren's syndrome. These antibodies are distinct from antibodies to single- and double-stranded DNA and double-stranded RNA. Poly rA binding is associated with IgM and IgG serum fractions. Because poly rA may have a role in the transcription of mRNA in mammalian cells and viruses, antibodies to poly rA may be important clues to virologic and immunogenetic mechanisms in the pathogenesis of SLE.


Antibody-dependent cell-mediated cytotoxicity in rheumatoid arthritis. Effect of rheumatoid serum fractions on normal lymphocytes.

Reduced antibody-dependent cell-mediated cytotoxicity (ADCC) was demonstrated in lymphocytes of patients with rheumatoid arthritis (RA). Rheumatoid factor (RF) positive sera inhibited ADCC of normal lymphocytes by reacting both with effector and target cells (sensitized chicken red blood cells). These sera were fractionated by specific adsorption or gradient ultracentrifugation, and isolated RF or RF negative fractions were tested for their ability to inhibit ADCC by reacting with normal human lymphocytes or target cells. RF was ineffective on normal lymphocytes but it strongly inhibited the reaction by interaction with target cells. IgG RF negative fractions of certain sera were inhibitory by direct interaction with effector cells.


Allergy in systemic lupus erythematosus. IgE levels and reaginic phenomenon.

Twenty-seven patients with systemic lupus erythematosus (SLE) were investigated for the presence of allergic reactivity, and serum IgE levels were measured by immunoassay. Compared to controls, SLE patients had significant increases of only allergic rhinitis and drug allergy. Despite the usual hyperimmunoglobulinemia in SLE, IgE levels were not elevated (mean: 251 IU). Because recent reports have noted elevated IgE in rheumatoid arthritis, this finding may suggest basic immunologic differences between rheumatoid arthritis and SLE.


Serum immunoglobulins, rheumatoid factor, and pneumoconiosis in coal miners with rheumatoid arthritis.

The occurrence and severity of pneumoconiosis were studied in 100 coal miners with rheumatoid arthritis (RA) and compared to findings in a geographically relevant survey of coal workers' pneumoconiosis. Contrary to European reports, miners with RA were not found to have an excessive frequency or severity of pneumoconiosis. In 55 of these men, serum immunoglobulin levels and rheumatoid factor were compared with data from matched RA patients with no history of silica exposure. The immunochemical results were unrelated to the stage of pneumoconiosis, nor did they differ from those in the control group.


The role of osmic acid in the treatment of immune synovitis.

Thirty-seven New Zealand rabbits were observed for up to 1 year after their knee joints were instilled with 1 ml of 1% osmic acid. A selective destruction of synovial lining cells occurred with a concurrent synovitis, but lining cell regenerated by the eighth week. Nonprogressive abnormalities were also present in the cartilage. When an immune synovitis was induced in both knees of 16 rabbits, the osmic acid treated joint demonstrated a significantly greater synovitis and progressive aberrations compared to the untreated knee.


Cardiovascular abnormalities in the Marfanoid hypermobility syndrome.

Two patients are described who had the body habitus of the Marfan syndrome, cutaneous hyperextensibility, and atrophic "cigarette paper" scars. One had mild joint hypermobility and the other had generalized ligamentous laxity. Both individuals are considered to be examples of the Marfanoid hypermobility syndrome, a generalized heritable connective tissue disease with features of, but genetically distinct from, the Marfan and Ehlers-Danlos syndromes. One patient had a "floppy" mitral valve and the other had an aortic aneurysm due to cystic medionecrosis of the aorta; both findings provide evidence that cardiovascular disease may be a significant feature of this syndrome.


Carrageenin-induced arthritis. I. The effect of intraarticular carrageenin on the chemical composition of articular cartilage.

A single intraarticular injection of carrageenin into rabbit knee joints initiated a localized synovial inflammatory response. This response was accompanied by a 20% loss of proteoglycan from the articular cartilage within 24 hours and by a further 30-60% loss within 5-7 days. The chondrocytes replaced the lost proteoglycan within 42 days. More than two injections caused only a further small decrease in proteoglycan content; the cartilage was then unable to replace the lost proteoglycan. The absence of recovery coincided with the appearance of erosion of the cartilage surface.


Arthritis Rounds: Ascites as the major manifestation of systemic lupus erythematosus.

It is uncommon for ascites secondary to severe peritoneal inflammation to be the major manifestation of systemic lupus erythematosus. Chronic nonspecific inflammation with a granular type immunofluorescent staining along the mesothelial layer of the peritoneum and peritoneal blood vessels was demonstrated in peritoneal tissue obtained at laparotomy. Paramyxovirus-like structures were seen within vascular endothelium. The ascites diminished with high-dose prednisone and cyclophosphamide therapy.


Hypercholesterolemia and aortic collagen synthesis in rabbit aortas.

Male adult New Zealand rabbits were fed a 2% cholesterol diet for 30 of 60 days in order to determine the effect of hypercholesterolemia on aortic collagen synthesis. Collagen synthetic activity was estimated by measuring tissue prolyl hydroxylase activity and the amount of tissue collagen was estimated by measuring tissue hydroxyproline levels. Following 30 or 60 days of feeding there was a significant increase in both tissue and serum cholesterol indicating the onset of hypercholesterolemia. Measurement of collagen synthetic activity and tissue collagen levels demonstrated no increase over control tissues. These data therefore indicate that hypercholesterolemia is not a direct stimulus of tissue collagen synthetic activity.


The role of ascorbic acid in the regulation of cholesterol metabolism and in the pathogenesis of artherosclerosis.

Strong clinical and experimental evidence suggests that chronic latent vitamin C deficiency leads to hypercholesterolaemia and the accumulation of cholesterol in certain tissues. Ascorbic acid supplementation of the diet of hypercholesterolaemic humans and animals generally results in a significant reduction in plasma cholesterol concentration. While most studies relating ascorbic acid to atherosclerosis have used the rabbit as a model, those concerned with elucidating the role of ascorbic acid in the regulation of cholesterol metabolism have generally used the guinea pig. Comparatively little use has been made of the non-human primates. A significant advance in recent years has been the development of a model of chronic latent scurvy in the guinea pig. Chronic dietary inadequacy of vitamin C may  influence the pathogenesis of atherosclerosis as it affects not only plasma cholesterol and triglyceride concentrations but also the integrity of the vascular wall. Ascorbic acid is involved in the regulation of cholesterol metabolism in several ways. Dietary inadequacy of vitamin C is associated indirectly with a lowering of cholesterol absorption, this effect resulting from a reduction in the availability of bile acids, monoglycerides and fatty acids. The excretion of cholesterol as neutral steroids, however, appears not to be affected by ascorbic acid. Although much of the evidence for the involvement of ascorbic acid in cholesterol synthesis is equivocal, it seems likely that cholesterol synthesis is decreased in vitamin C deficiency. A series of studies using guinea pigs with chronic latent vitamin C deficiency has provided clear evidence that bile acid synthesis is reduced in this condition. Indirect evidence strongly suggests that this results from a decrease in the activity of the microsomal enzyme cholesterol 7 alpha-hydroxylase. However, some evidence suggests that the mitochondrial reactions of bile acid synthesis require ascorbic acid. The role of ascorbic acid in the regulation of steroidogenesis appears to involve selective inhibitory and stimulatory effects on the desmolase, hydroxylase and dehydrogenase reactions which lead to the formation of pregnenolone and its subsequent conversion to steroid hormones.


Comparative effects of prolactin, perphenazine and reserpine on non-arteriosclerotic (virgin) vs arteriosclerotic (breeder) rats.

Non-arteriosclerotic, virgin and arteriosclerotic breeder rats were subjected to chronic treatment with prolactin or prolactin-releasing drugs such as perphenazine and reserpine for 12 weeks. Males and females responded to the prolactin as evidenced by increased milk secretion, adrenal hyperplasia and thymus gland involution. Although the prolactin- and reserpine-treated animals gained weight and manifested pituitary gland basophilia, the perphenazine-treated animals showed considerable loss of body weight as well as involution of the pituitary gland, ovaries and testes, suggesting a condition of induced hypopituitarism. Chronic treatment with prolactin, both directly and indirectly, caused uniform increases in serum enzymes, e.g., CPK, SGOT, SGPT and LDH, lipids, e.g., triglycerides, free fatty acids and cholesterol, glucose and BUN. Corticosterone production was enhanced by prolactin, reduced by perphenazine and unaffected by reserpine. Prolactin did not induce any arterial disease in the arteriosclerosis-resistant, virgin rats but it did cause eracerbation of the usual severity of arteriosclerosis in the hilar renal arteries of the arteries sclerosis-prone, breeder rats as well as an increased incidence of "old" and "new" foci of myocardial necrosis, characteristically found in breeder rats. It is suggested that hypothalamic control of prolactin as well as ACTH release may play a role in the spontaneous arteriosclerosis which develops in repeatedly-bred, male and female rats.


Scanning (SEM) and transmission (TEM) electron-microscopic studies on post-ischemic endothelial lesions following recirculation.

The endothelial surface of the vessel wall was studied after various period of recirculation following transitory mechanical hypoxia. The acute changes consisted of partial or total destruction of the endothelium in certain areas. Later on, the regeneration (division and process-formation) of endothelial cells took place over the damaged areas. These events were demonstrated both by transmission and scanning electron microscopy. When severe vessel damage occurred, the subendothelial matrix, collagen and elastic fibres, and the stomata were also set free. Blood cells anchored to these areas were later covered by endothelium. Regeneration was practically complete after 10 days; previously only some small endothelial processes had shown evidence of regenerative activity. In spite of the extensive damage to the endothelium, no occluding thrombus formation was seen. The phagocytes functioned only in removing debris, and the thrombocytes in facilitating endothelial overgrowth.


Lipid metabolism in cultured aortic smooth muscle cells and comparison with other cell types. Part I. Composition of cells grown in hyperlipemic serum.

The lipid compositions of cultured rabbit aortic smooth muscle cells, adventitial fibroblasts and skin fibroblasts were determined for cells grown in media containing either normolipemic or hyperlipemic serum. No significant changes were found in cell phospholipid composition. Each of the threee cell types responded similarly to hyperlipemic serum, accumulating esterified cholesterol and triglyerides.


Diminished baroreceptor sensitivity in elderly hypertensives. Possible role of atherosclerosis.

Baroreceptor sensitivity was studied in twelve young normotensive subjects and forty hypertensive patients, separated into two groups according to their age, severity of hypertension and signs of severe atherosclerotic vascular disease. Under stabilized circulatory conditions, the changes of pulse rate in response to changes of blood pressure, attained by infusion of trimethaphan camphorsulfonate alone or with norepinephrine, was examined. There was gradually diminished change of pulse rate in relationship to blood pressure change as age and hypertension advanced. However, although the blood pressure threshold of stimulation was obviously higher in the middle-aged hypertensive subjects than in the normotensive ones, the slightly reduced baroreceptor sensitivity was not significantly different from that  in the normotensive group. Only in the elderly hypertensive patients was significantly diminished baroreceptor sensitivity demonstrated, which was also significantly different from that in the middleaged hypertensive patients. It is speculated that the significantly diminished baroreceptor sensitivity found in the elderly hypertensive patients may be due to atherosclerotic changes in the region of the baroreceptor, although proof of that is not available at the present time.


Age-related chemical changes in human elastins from non-atherosclerotic areas of thoracic aorta.

Elastins from normal appearing areas of human thoracic aortae with varying degrees of mineralization were taken from subjects of different ages and purified by autoclaving their amino acid compositon, Ca and P contents and N terminal profiles were determined before and after EDTA decalcification. (1) Decrease in desmosine concentration with increasing age was accounted for by dilution of the elastin by autoclave-resistant polar glycoproteins. (2) The appearance and growth of a mineral phase with a Ca/P molar ratio typical of apatites was accompanied by an increased association of polar contaminants with elastin. (3) After 24 h EDTA treatment, small and constant amounts of Ca were still apparent although P was absent, in elastins from all age groups. (4) The undialyzable fraction of the material solubilised by EDTA consisted mainly of elastin fragments, glycoproteins and Ca. (5) All the elastin samples showed the same type of N-terminal amino acids. In low and medium mineralized samples the concentration of amino end-groups was slightly increased, while in highly mineralized elastin the content of N-terminal residues was three times greater than in normal young elastin. Extraction with EDTA reduced the amount of end-groups to a normal level. It is suggested that in the initial stages of elastin fibre mineralization, an increased amount of autoclave-resistant glycoproteins becomes associated with elastin; and that with ageing, degradative changes involving peptide-bond cleavage may occur. However, evidence of degradation is found only in old and highly mineralized elastin samples.


Enzymes of DNA synthesis in isolated nuclei of swin aorta.

Enzymes of DNA synthesis, thymidine kinase (ATP-thymidine-5'-phospho-transferase, EC 2.7.1.21), DNA polymerase (EC 2.7.7.7) and nuclease activities were investigated in isolated purified nuclei of swine aorta. Thymidine kinase which is detectable in these nuclei can be stimulated by the addition of phospholipase C. DNA polymerase activity of isolated nuclei is strongly dependent on addition of an exogenous template; the preferred template is activated DNA. The activity in the absence of an added template is very low except when labelled dCTP is used as the precursor. This incorporation of labelled dCTP does not require the addition of the other three triphosphates, and under these conditions, dCTP seems to be incorporated into what may be a homopolymer. As with other tissues, solubilized preparations of aortic nuclei have two DNA polymerase activities which also prefer activated DNA template. There is no detectable endonuclease in aortic nuclei.


Vitamin A and lysosomal stability in rats fed an atherogenic diet.

The relation between vitamin A status and lysosomal stability was studied in rats fed a high fat-cholesterol diet. Increase in the total activity of lysosomal enzymes as well as that in the nuclear fraction, intact lysosomal fraction and free activity (activity present in the 15,000 X g supernatant) in the liver was observed in rats fed an atherogenic diet with adequate vit. A. Vitamin A deficiency and hypervitaminosis (10,000 IU) augmented this increase in the total enzyme activity as well as the activity in the subcellular fractions except in the case of intact lysosomes where the activity was not significantly altered. At 2,000 IU, there was no significant alteration in either the total activity or the activity of the subcellular fractions. An analysis of the ratio of soluble activity (released from the lysosomes) to the activity present in the intact lysosomes, showed that hepatic lysosomal stability was decreased in the rats fed an atherogenic diet with normal dose of vit. A. Vitamin A deficiency as well as hypervitaminosis decreased the lysosomal stability still further. At a dose of 2,000 IU, lysosomal stability increased as compared to the rats fed an adequate dose of vit. A, while total lysosomal activity remained not significantly altered. Studies on the rate of release of enzymes from the lysosomes revealed that there was significantly more release of the enzyme between 30 and 45 min in the liver and aorta in the rats fed a high fat-cholesterol diet with adequate vit. A This release was still more in the rats fed a low dose of vit. A. At 2,000 IU, there was no significant difference in the enzyme release. But the pattern of change in the liver and aorta in the hypervitaminotic group was different. In the case of hepatic lysosomes, there was an increase in the enzymes released while in the aorta there was significant decrease. This has been attributed to the fact that lytic concentration of the vitamin A is not attained in the aorta.


Lipid-lowering activity of phytostanols in rats.

In the present study, the hypocholesterolemic activity of phytosterols and phytostanols was compared. Phytostanols were prepared by hydrogenating a phytosterol mixture from corn oil and were fed at different levels (0.1-1.0%) to male rats for 10 to 14 days with or without cholesterol (1.0%). In an appropriate combination with cholesterol, phytostanols showed significantly greater activity in lowering the plasma and possibly liver cholesterol levels in comparison with the corresponding phytosterols. The stanols further stimulated the fecal recovery of cholesterol. The rate of intestinal absorption of phytostanols appeared obviously lower than that of phytosterols and thus the deposition into plasma and liver lipids was almost negligible.


Preprandial drinking and plasma lipids in man.

A group of normolipemic subjects who consumed alcoholic drinks before their evening meals for a period of 7 consecutive days demonstrated a significant increase in their fasting plasma triglyceride levels. On cessation of alcohol consumption, the fasting triglyceride levels reverted to their pre-experimental levels. The plasma cholesterol levels did not show any consistent changes.


Effect of unilateral nephrectomy of the localization of aortic sudanophilic lesions in cholesterol-fed rabbits.

The method of polar coordinate mapping of lesions on the aortic wall around orifices was used to study the effect of unilateral nephrectomy on sudanophilic lesions in rabbits. Four groups of six rabbits each were studied. Group I had a right nephrectomy with a short renal artery stump. Group II had a sham right nephrectomy. Group III had a left nephrectomy with a short renal artery stump and Group IV a sham left nephrectomy. All groups were allowed to recover for one week and were then fed rabbit chow enriched with 2% cholesterol and 6% corn oil for a four-week period. Groups I and III showed a marked alteration in lesions around the stump with both proximal and distal peaks. Group I also showed the development of skewing of the left renal lesion to the left, presumably because of a change in aortic flow due to removal of the proximal right renal flow. The right renal artery had a lesion skewed to the right; this was not altered by left nephrectomy and was probably due to coeliac flow. The data provides strong evidence that sudanophilic lesions in rabbit aortas are altered by local flow disturbances.