De subitaneis mortibus. XIX. On the cause of sudden death in pheochromocytoma, with special reference to the pulmonary arteries, the cardiac conduction system, and the aggregation of platelets.

Pheochromocytoma may cause sudden and unexpected death. In this study of three fatal cases of pheochromocytoma the small pulmonary arteries were narrowed by a variety of chronic and acute processes which included medial hypertrophy and fibrosis, endothelial proliferation and fibrosis, and endothelial cellular edema; within the sinus node, atrioventricular (A-V) node and His bundle of all three cases there was focal degeneration and fibrosis similar to that also observed throughout the ventricular myocardium; and in addition to the focal narrowing of many small coronary arteries produced by medial hypertrophy, intimal fibrosis, and fibromuscular dysplasia, there were also focal aggregations of platelets clogging the lumen and occasionally mixed with a varying amount of fibrin. In patients known to have pheochromocytoma it may be necessary to direct new attention to the possibility of abnormal pulmonary vascular resistance, instability of normal cardiac rhythm, and perhaps difficulty in restoring it when disordered and to the effects of platelet aggregations, both causing acute obstruction and possibly contributing to the pathogenesis of chronic vascular disease.


Factors in allergen-induced asthma: relevance of the intensity of the airways allergic reaction and non-specific bronchial reactivity.

Early asthmatic responses (EAR) of similar severity were produced by allergen inhalation challenges in nine asthmatic subjects. The severity of the airways allergic reaction was estimated by measuring the skin test weal size produced by the same dilution of allergen which caused the EAR. The non-specific bronchial reactivity was assessed by inhalation of incresing concentrations of histamine acid phosphate. Possible relationships between the severtiy of the airways allergic reaction, the level of non-specific bronchial hyper-reactivity and the pattern of asthmatic response were examined. There was a marked inverse correlation between the required severity of the airways allergic reaction and the non-specific bronchial reactivity (log10) of the individual (r = -0-96, P less than 0-001). The EAR was followed by a late asthmatic response (LAR) in five subjects. There was no evident correlation between the magnitude of the EAR and that of the LAR. In addition, no correlation was obtained between the pattern of response interms of EAR or LAR and the severity of the allergic reaction, or the level of non-specific bronchial reactivity. These results indicate that the allergic reaction and the non-specific bronchial reactivity are interrelated in the production of allergen-induced asthma. Thus a mild allergic reaction will induce and EAR in patients with markedly increased non-specific bronchial reactivity, whereas a severe allergic reaction is required to produce an EAR in those with only slightly increased non-specific reactivity. The lack of correlation between the occurrence of the LAR and the intensity of the airways allergic reaction, the non-specific bronchial reactivity and the intensity of the EAR indicates that other factors are involved in the development of LAR.


The IgG subclasses of antibodies to grass pollen allergens produced in hay fever patients during hyposensitization.

Total IgG, IgG subclass and IgE antibodies specific for grass pollen allergens were measured by the red cell linked antigen-antiglobulin reaction (RCLAAR) in a serum samples from nineteen patients who had undergone a course of hyposensitization. Increases in both specific IgG and IgE antibodies were seen after treatment in most patients. In the IgG subclasses the predominant response was for IgG1 and IgG4 antibodies. Attempts were made to correlate the antibody responses with the clinical response and the results are discussed with reference to the possible mechanisms of hyposensitization.


Elevated serum IgG4 levels in cystic fibrosis patients.

The quantitative measurement of the IgG subclass composition of the sera from sixteen patients with cystic fibrosis has revealed grossly elevated levels of IgG4 in seven patients. The possible significance of this observation is discussed in relation to recent reports of a high incidence of immediate-type hypersensitivity in such patients.


Bakers' asthma.

Bronchial provocation tests by "occupational" exposure to flour provoked dual asthmatic reactions accompanied by rhinitis in two atopic bakers engaged in the manufacture of bread and pies. Ingestion tests with uncooked flour produced no reactions. Skin prick tests with aqueous extracts of flour produced positive immediate reactions in both bakers, and negative reactions in nine of ten atopic asthmatic control subjects with no occupational exposure to flour. Intracutaneous tests, performed in one precipitin negative baker, gave dual responses. Precipitating antibodies to an aqueous extract of flour were found in the unconcentrated serum of the other baker, and not in ten control subjects.


Retrospective survey of 1271 patients diagnosed as perennial rhinitis.

Data from 1271 patients with perennial rhinitis has been assessed. This condition predominantly affects children and young adults; 31-5% stated that symptoms first appeared before the age of 10 years, less than 10% were aged 50 years or more suggesting that the disease process may well disappear in later life. The total sample size was equally divided between the sexes and the mean age for the sexes was similar. In terms of age distribution a sex difference was found in that the peak incidence for males occurred in the age group 10-19 years whereas for females it was in the third decade (P less than 0-001). The duration of the disease was, in most cases, between 2 and 9 years but it can extend to over 15 years and thus become subacute or chronic. The major symptom is blocking which could be due to either histological changes in the mucosa or immunological reactions. Skin tests showed that 64% had a positive reaction to common allergens; however, nasal challenge tests were of little value in determining whether a patient could be classified as allergic. Eosinophils were noted in 66%. The value of skin tests and nasal smears is discussed.


Allergy to a tetracycline preparation-a case report.

Immediate asthmatic and urticarial reactions were provoked in an affected subject by ingestion of a commercial combination of three tetracylines. No reactions were elicited by the tetracyclines given separately or prepared together as a powder; this was perhaps due to tachyphylaxis, since a test with the commercial preparation 2 months later elicited the reactions again. No reactions were elicited by the blue coating of the commercial preparation or by tartrazine.


Routine assay for the detection of immune complexes of known immunoglobulin class using solid phase C1q.

A new, sensitive and quantitative technique for the routine estimation of immune complexes has been devised. The assay involved the binding of immune complexes to Clq linked to the surface of plastic tubes; the amount of immune complex bound is then determined by adding radiolabelled anti-human IgG. Immune complexes were detected in twelve out of thirty-one patients with systemic lupus erythematosus. The test should prove useful in the diagnosis of immune complex diseases and will be valuable in the evaluation of disease activity.


Measles infection. Involvement of the complement system.

The complement system was examined in fifty patients with acute, apparently uncomplicated measles; forty-six were children less than 10 years old. Twenty showed evidence of pathological complement activation. In thirteen of these the pattern was consistent with activation of the classical pathway while in the other seven data suggested utilization of an alternative pathway. An additional eleven patients had isolated reduction in Clq without alteration in concentration of other components; these were excluded from the classical pathway group. No patient had detectable immune complexes or C3 splitting activity in serum; however, it is suggested that the abnormal complement patterns observed are likely to indicate the presence of circulating immune complexes in a high percentage of patients with this infection.


Studies on blood eosinophils. I. Patients with a transient eosinophilia.

Studies were done on blood eosinophils from six patients with a transient eosinophilia, to see whether blood eosinophils were structurally or functionally different from blood eosinophils in eleven normal individuals. It was found that many of the patients' eosinophils were vacuolated, and some contained less specific granules than normal. These eosinophils also possessed Fc receptors for rabbit IgG. When the eosinophil counts returned to normal these abnormalities were no longer found. The nature of these alterations are discussed in relation to the properties of eosinophils in tissues and other types of phagocytic cells responding to stimulae. Suggestions are made about the mechanisms by which they could have come about. It was concluded that blood eosinophils in patients with an eosinophilia may be functionally mature or altered in response to unknown stimulae while they are in the blood.


Studies on blood eosinophils. II. Patients with Löffler's cardiomyopathy.

Studies were done on blood eosinophils from four patients with raised blood eosinophil counts and heart failure. In three of the patients cardiological studies demonstrated the distinctive endocardial lesions and restrictive cardiomyopathy of Löffler's endocarditis and endomyocardial fibrosis. The fourth patient died with similar symptoms and signs. In blood films it was found that all four had more than 1 X 10(9) eosinophils per litre which were vacuolated and contained reduced numbers of crystalloid granules which were also shown to have ultrastructural changes. Unlike eosinophils from normal individuals the patients' eosinophils possessed receptors for rabbit IgG-coated erythrocytes and actively phagocytosed erythrocytes coated with rabbit IgG or human C3b. It is concluded that in these patients, a large proportion of the circulating eosinophils had developed characteristics of mature or stimulated eosinophils. This enabled them to respond to soluble substances in the bloodstream by forming endocytic vacuoles which led to degranulation of the crystalloid granules. These studies, taken in conjunction with other recent work in this field, support the concept that the restrictive cardiomyopathy of hypereosinophilic states, including Löffler's endocarditis and endomyocardial fibrosis, is a result of prolonged release of products from degranulated eosinophils while they are in the circulation.


The role of C3 in the autologous phase of nephrotoxic nephritis.

The role of complement has been studied in the autologous phase of nephrotoxic nephritis (NTN) in rabbits. No reduction in glomerular fibrin deposition, crescent formation or protection from renal failure was observed in either the standard model of NTN when decomplementing doses of cobra venom factor (CVF) were given before the autologous phase or in a telescoped model when CVF was administered before the nephrotoxic antibody. In the latter situation glomerular fibrin deposition and crescent formation were found in the absence of detectable deposition of C3. However, substantial protection was observed when circulating polymorphonuclear leucocytes (PMN) were depleted by antipolymorph serum. These observations establish the existence of a system of allergic glomerular injury mediated by PMN but independent of C3. It is postulated that this system may account for the glomerular injury seen in patients with Goodpasture's syndrome in whom glomerular C3 deposition is not found.


The cofactors required by C3 nephritic factor to generate a C3 convertase in vitro.

The mechanisms by which a C3 convertase is generated by C3 nephritic factor (NeF) were investigated using purified NeF, C3, C3b, factor B and factor D of the alternative pathway of complement activation. NeF could generate a C3 convertase with C3 and B in the absence of D, and without cleavage of B. At lower concentrations of NeF the addition of D was required to generate a C3 convertase, and B cleavage now occurred. The generation of both the D-independent and D-dependent C3 convertases with NeF was inhibited by preincubation of the C3 source with C3b inactivator (KAF); isolated C3b was more efficient than the C3 preparations used in generating the D-independent C3 convertase with NeF. These experiments indicate that C3b is required for the formation of both convertases, and that the reaction occurring with apparently native C3 is due to trace amounts of C3b. It is concluded that the C3 convertase generated by NeF in the absence of D is C3bB (NeF), and that generated in the presence of D is the feedback convertase C3bBb. The relevance of these experiments to reactions which may occur in vivo is discussed.


Studies on the production and action of polymorph migration stimulator.

Human blood monocytes are known to react with hydrocortisone in vitro to produce a factor which stimulates polymorph migration. This study shows that the polymorph migration stimulator (PMS) is generated only by steroids with glucocorticoid activity. The interaction between steroid and monocytes is dependent on protein synthesis. Serum is necessary for the expression of the activity of the factor, but the steroid-monocyte reaction can occur in the absence of serum. The stimulatory effect on migration appears to be specific for polymorphs and does not affect mono-nuclear leucocytes. In addition to blood monocytes, spleen and bone marrow cells also react with corticosteroids to produce the polymorph migration stimulator.


Report of nine cases of accidental injury to man with Freund's complete adjuvant.

Nine cases of accidental injury with Freund's complete adjuvant to man are reported. One case is reported in detail and the other eight have been seen and reviewed retrospectively. Reactions developed in Mantoux positive individuals, who injected Freund's complete adjuvant with another protein. However, not all such injections produced the reaction. Treatment was unsuccessful, although one reaction may have been aborted by early surgical excision of the site of injection.


Animal model of sensitization by inhalation.

Groups of rats exposed to daily inhalation challenge with aerosolized pigeon serum developed precipitating antibody within 2 weeks and definitive granulomatous inflammatory changes in the lung after 7 weeks of exposure. The dissociation of the two responses to an inhalation challenge indicate that the rat model may serve for screening of the various inhalant antigens for their sensitizing potential, and for investigation of the contributory role of some of the factors involved in the pathogenesis of hypersensitivity pneumonitis.


The antecubital fossa fistula.

We have reviewed our experience with 19 proximal forearm arteriovenous fistulas used in chronic hemodialysis. Thirteen functioned adequately, and of these 10 were complicated by dislodge needles during dialysis, arm edema or hematomas. Although 3 patients developed symptoms of arterial steal, none required ligation of the fistula. This experience suggests that antecubital fossa fistulas might best be used as a second line angioaccess when distal forearm fistulas have been unsuccessful or are impossible to contruct.


Candida endocrinopathy syndrome with membranoproliferative glomerulonephritis: demonstration of glomerular candida antigen.

A boy who had the Candida endocrinopathy syndrome, consisting of mucocutaneous candidiasis, hypoparathyroidism and hypoadrenocorticism, also had hypocomplementemic  membranoproliferative glomerulonephritis. A renal biopsy at age 16 showed lobular glomerulonephritis with chronic interstitial inflammation. Glomerular and focal tubular deposition of IgG and C3, but not C4, were seen by immunofluorescence microscopy. Electron microscopy revealed dense intramembranous deposits in glomerular, tubular and Bowman's capsul basement membranes. C. albicans antigenic material was detected in the glomeruli by immunofluorescence microscopy using an FITC-labelled rabbit antiserum to the patient's organism. These fidings suggest that chronic C. albicans infection led to an immune complex form of nephritis. Clinical and laboratory evidence of resolution of his nephritis and return to normal serum levels of C3 followed prolonged antifungal therapy.


Effect of posture on renal lithium clearance.

1. Renal lithium clearance in healthy men was elevated while the subject was reclining, decreased upon standing and increased upon lying down during 45-60 min tests. 2. Parallel changes in renal clearance of creatinine, sodium and potassium, and urine flow rate occurred in response to the changes in posture. 3. The findings demonstrate for the first time that posture is a factor that can influence lithium excretion. Control of posture during lithium excretion tests is recommended.


Effects of p-chlorophenoxyisobutyrate on free fatty acid mobilization from canine subcutaneous adipose tissue in situ.

1. The mechanism whereby p-chlorophenoxyisobutyrate (CPIB) lowers plasma non-esterified fatty acid concentrations has been studied in dogs by measuring the associated changes in adipose tissue metabolism. 2. CPIB lowered arterial concentrations of non-esterified fatty acids during isoprenaline infusion by a mean value of 41%. 3. This was accompanied by a proportionate decrease (45%) in the release of non-esterified fatty acids from subcutaneous adipose tissue in situ, and by a lesser reduction (22%) in than of glycerol. 4. Adipose tissue blood flow was unchanged by CPIB. 5. These findings indicate that the lowering effect of CPIB on non-esterified fatty acid concentrations derives principally from decreased mobilization rather than from increased tissue uptake of the fatty acids, and that this reflects both inhibited lipolysis and enhanced re-esterification of the fatty acids in adipose tissue.


Functional and biochemical evidence of damage to enterocytes induced by triparanol: role of lysosomes and the effect of gluten-free diet.

1. Functional and biochemical studies were performed on the small intestine of control rats, and the results were compared with similar studies on animals given triparanol at a dosage of 0.114 mmol/kg daily for 10 days. The animals given triparanol were fed with either standard rat food or a gluten-free diet. 2. By using a recirculating-perfusion technique in vivo, it was shown that absorption of galactose from an 8 mmol/l solution was impaired in the ileum but not in the jejunum of the triparanol-treated rats. 3. Assays of marker enzymes for the principal subcellular organelles were performed on isolated jejunal and ileal enterocytes. In the ileum there was a striking decrease in lysosomal enzyme activities and a smaller but significant decrease of lactate dehydrogenase, catalase and malate dehydrogenase activities. In the jejunum there was no significant change in the activities of these enzymes. 4. Measurements of lysosomal integrity indicated that ileal lysosomal fragility was markedly increased and that jejunal lysosomes were affected to a much smaller extent. 5. These effects of triparanol could not be ameliorated by feeding with a gluten-free diet.


Cystinuria: a new genetic variant.

1. A family is reported with an unusual type of cystinuria. 2. The propositus presented with a cystine renal stone; the renal tubular reabsorption of cystine was grossly abnormal but the tubular reabsorption of ornithine, lysine and arginine was only slightly less than normal. 3. One of the children of the propositus escreted cystine and lysine in increased amounts typical of type II heterozygotes for cystinuria. 4. The renal transport defect in this family may represent one end of the spectrum of cystinuria or it may be a form akin to isolated hypercystinuria.


Effect of vasopressin on uric acid excretion: evidence for distal nephron reabsorption of urate in man.

1. When changes in urine flow rate were induced by vasopressin administration in eight subjects, urate excretion decreased by a mean of 14% and was positively correlated with urine flow rate (r = 0.88, P less than 0.01). The effect of vasopressin on urate excretion was not influenced by prior changes in extracellular fluid volume. 2. Mannitol administration in a dose sufficient to prevent vasopressin-induced alterations in urine flow rate blocked the effect of vasopressin on urate excretion. 3. Alterations in urate excretion produced by changes in extracellular fluid volume could be distinguished from the urate-retaining effect of vasopressin-mediated decrease in urine flow. Urate retention after vasopressin was entirely attributed to a decrease in pyrazinamide-suppressible urate excretion, consistent with either decreased secretion or enhanced post-secretory reabsorption of urate. 4. Since diminished urine flow rate in the distal part of the nephron is more likely to lead to enhanced reabsorption of urate, these results provide additional evidence for urate reabsorption in the distal part of the nephron.


Differential effects of Asp-angiotensin II and Sar-angiotensin II on vascular and adrenal receptors in the dog.

1. Adrenocorticotrophic hormone-suppressed, bilaterally nephrectomized male mongrel dogs (n = 12) were infused with Sar1-angiotensin II and Asp1-angiotensin II, the naturally occurring octapeptide. 2. Sar1-angiotensin II was found to be almost twice as potent as Asp1-angiotensin II in elevating blood pressure but its aldosterone-stimulating activity was not higher than that of the naturally occurring peptide. 3. A specific competitive antagonist of angiotensin II, Sar1-Ile8-angiotensin II, blocked the pressor but not the aldosterone-stimulating activity of Sar1-angiotensin II. 4. These results suggest functional differences in receptors for angiotensin II in vascular smooth muscle and in adrenal cortex.


The transport of endogenous vitamin B12 in normal human serum.

1. Serum from normal subjects has been chromatographed on Sephadex G-200 columns and the fractions containing transcobalamins 0, I and II have been identified. 2. The fractions corresponding to transcobalamin I contained, on average, 90% of the endogenous vitamin B12. Only 3% was attached to transcobalamin 0, and 7% was bound to transcobalamin II.


The forced expiratory time as a measure of small airway resistance.

1. In five subjects, ten consecutive forced expiratory spirograms were recorded on each of 6 different days and the total forced expiratory time (FET) on each spirogram was measured. The mean overall coefficient of variation of the FET was 11.3% and of the ratio forced vital capacity (FVC)/FET was 8%. 2. Twenty-two subjects with probable small (less than 2 mm diameter) airway dysfunction as manifested by a reduced (less than 75% predicted) maximum mid-expiratory flow (MMEF) in the middle 50% of the FVC with normal FVC and FEV1 (greater than 80% predicted) were studied before and after bronchodilatation. There was no significant correlation between change in FET and change in MMEF (r = 0.36, P greater than 0.01), but between change in MMEF (deltaMMEF) and change in FVC/FET (deltaFVC/FET) there was a positive correlation (r = 0.78, P less than 0.001). 3. In six of these twenty-two subjects, the deltaFVC/FET and deltaMMEF on bronchodilatation correlated well with the change in residual volume (deltaRV). but neither measurement correlated well with the change in the 'closing volume' measurement expressed as the ratio of phase 4/VC(%). The deltaFET did not correlate well with either deltaRV or delta[phase 4/VC(%)]. 4. In eighty-one selected normal subjects (FVC, FEV1 and MMEF all greater than 80% predicted) there was better correlation of age with the FVC/FET (r = -0.676) than with the FET (r = +0.43); both correlations were significant (P less than 0.001). 5. These results do not support the use of the FET as a suitable test of small airway function; however, the mean flow rate expressed as FVC/FET may, in the presence of a normal FEV1/FVC ratio, be an adequate test of small airway function.


The effect of the porphyrogenic compound, hexachlorobenzene, on the activity of hepatic uroporphyrinogen decarboxylase in the rat.

1. A new method for the measurement of uroporphyrinogen decarboxylase (EC 4. 1.1.37) in rat liver homogenates, with 5- carboxyl porphyrinogen as substrate, is described. 2. The administration of a diet containing 0-3% (w/w) hexachlorobenzene produces porphyria in female Wistar rats after a delay of at least 4 weeks. The development of porphyria is accompanied by a progressive fall in hepatic uroporphyrinogen decarboxylase activity to 18% of control values after 11 weeks. The features of hexachlorobenzene prophyria are consequences of this enzyme defect. 3. Feeding with hexachlorobenzene did not lead to the accumulation of iron in the liver. It is suggested that hexachlorobenzene or a metabolite acts directly to decrease the activity of the enzyme.


Stimulated flow of pancreatic and biliary secretions after intestinal exposure to cholera toxin.

1. Duodeno-jejunal intestinal loops in rats were perfused with cholera toxin and the pancreatic and biliary secretory responses studied. 2. Intraluminal cholera toxin induced a significant flow of pancreatic and biliary fluid and sustained protein (enzyme) secretion in pancreatic juice, in addition to the expected stimulation of mucosal secretion. 3. Intravenously injected cholera toxin failed to elicit a secretory flow from the pancreas and biliary tract. 4. The time-course of the enhanced secretory flow from pancreas and biliary tract after intraluminal cholera toxin corresponds closely to the secretion of intestinal fluid. 5. The results of these studies provide evidence of sustained stimulation of pancreatic and biliary secretions after mucosal exposure to cholera toxin. These observations support the suggestion that secretion from the pancreas and liver may significantly contribute to the total intestinal secretion in cholera.


Effect of sotalol on haemodynamics and renin-angiotensin-aldosterone system in hypertensive patients.

1. Twenty-three hypertensive patients were treated by sotalol, a pure beta-adrenergic receptor blocking agent. The drug produced a significant decrease of blood pressure in nineteen patients. 2. On average, cardiac index decreased but not significantly; heart rate decreased and stroke index increased significantly. Total peripheral resistance varied in both directions. 3. Sotalol determined a fall in plasma renin concentration (only significant in the high-renin group), a fall in plasma angiotensin II concentration and in urinary excretion rate of aldosterone accompanied by a rise in plasma potassium concentration. 4. The fall of blood pressure was not correlated with the decreases of renin and angiotensin II concentrations or excretion rate of aldosterone. However, in the placebo period plasma angiotensin II concentration was significantly correlated with total peripheral resistance; during sotalol treatment the variations of these two parameters seemed also to be correlated. 5. There was a poor correlation between decreases of cardiac output and of blood pressure; it was impossible to foresee the magnitude of the lowering of the blood pressure from the initial cardiac index. 6. The association of a diuretic with sotalol enhanced the hypotensive effect of the beta-receptor blocking drug, without significant increase of plasma renin and angiotensin II concentrations.


The sodium-retaining effect of renal nerve activity in the cat: role of angiotensin formation.

1. The effect of low-frequency stimulation of the renal nerves on renal function and renin release has been investigated. The experiments were performed in unilaterally nephrectomized, anaesthetized cats in which the nerves to the remaining kidney were sectioned. 2. When stimulation frequency was adjusted to reduce renal blood flow by approximately 15% for 15 min, glomerular filtration rate was hardly affected. The ratio sodium clearance/glomerular filtration rate was significantly reduced and plasma renin activity was significantly increased. 3. When the renal nerves were similarly stimulated in the presence of the beta-adrenergic receptor blocking agent, propranolol, the glomerular filtration rate was significantly reduced and the rise in plasma renin activity was significantly inhibited. The reduction of sodium clearance/glomerular filtration rate was as great as in the control animals. 4. The results are consistent with the view that the maintenance of glomerular filtration rate, during renal nerve stimulation which reduced renal blood flow, may be mediated by the local generation of angiotensin. The results also suggest that angiotensin does not play an important role in the sodium retention associated with increased renal nerve activity.


Screening for drugs of abuse in urine samples from a drug addiction center.

The present analytical methods used in a laboratory monitoring urine specimens collected from patients attending one of the Drug Dependency Units are described and compared with other published methods. In particular a new and simple thin-layer chromatographic system and its application to the identification of the drugs of abuse extracted from urine samples is described. The results obtained during 1974 and February 1975 are tabulated, showing the trends in drug abuse that have occurred in one area of London during that period. The usefulness of these results and of urine monitoring in relation to the treatment of the addicts is also briefly considered.


Mass screening and confirmation of barbiturates in urine by RIA/gas chromatography.

A rapid, sensitive and specific procedure is described for the mass screening and confirmation of barbiturates in urine specimens. The method is sensitive to 0.5 mug/ml levels of the commonly used barbiturates. The urine samples are screened by radioimmuno-assay. Specimens  screened positive are confirmed by gas-liquid chromatography using a flame ionization detector. The barbiturates are analyzed as free acids on a 10% UC W-98 column and as their dimethyl derivatives on a 3% OV-17 column. This dual approach eliminates false positives caused by interfering substances which may be present in the urine, thus resulting in a method specific for the barbiturates.


Effect of dietary selenium on tumor induction by an oncogenic virus.

Mice exposed to selenium-supplemented or -deficient rations were inoculated with an oncogenic virus, Rauscher leukemia virus (RLV), Splenic lesions were not altered by dietary selenium supplementation or depletion. It is concluded that selenium does not affect neoplasia induced by RLV in mice.


Management of carbon monoxide poisoning in the absence of hyperbaric oxygenation chamber.

Manifestations of carbon monoxide poisoning are mostly attributable to acute hypoxic insult. In the absence of immediately available hyperbaric oxygen chamber, 100% oxygen should be delivered to the patient until carboxyhemoglobin levels in the blood are less than 5%. Presence of abnormal motor activity or prolonged abnormal consciousness are indications for proceeding with hypothermia and mechanical ventilation. Reversal of these manifestations was achieved in 3 reported cases though induction of hypothermia was delayed for as long as 24 hours. However, no beneficial effects were obtained in a fourth patient who did not receive hypothermia until 5 days after exposure. The duration of hypothermia varied between 60-70 hours in patients who showed near-complete recovery.


Measurement of closing volume in apneic subjects.

Closing volume measurement was adapted for application in apneic intubated, artifically ventilated subjects. A bolus of nitrogen was used as the marker gas. Inspiration and exhalation at a slow, uniform rate between residual volume and total lung capacity was provided by a 7000-ml syringe. Closing volumes in seven anesthetized subjects were similar to those reported for supine, conscious individuals by previous investigators. This adaptation of closing volume measurement should be useful in studying pulmonary dysfunction during anesthesia and during artificial ventilation of patients in respiratory failure.


Comparison of CSF-free amino acid concentrations among various neuropathological conditions.

The level of free amino acids in cerebrospinal fluid from eight patients in comatose states has been determined. The variations of cerebrospinal fluid-free amino acids observed in coma have been compared with those reported by other authors in patients affected by epilepsy, multiple sclerosis, infantile amaurotic idiocy (GM2-gangliosidosis) and phenylketonuria.


Bedside pulmonary angiography in the critically ill patient.

A simple technique to perform pulmonary angiography at the bedside in critically ill patients is presented. A central venous pressure catheter placed into the right ventricle or in the main pulmonary artery allows manual contrast injection into the vascular pulmonary tree which can be satisfactorily visualized by means of a "penetrated" chest x-ray film. The method discussed herein presents evidence of usefulness in establishing the differential diagnosis of acute pulmonary embolism in patients who cannot be mobilized or in those institutions where facilities of catheterization-angiographic laboratory are not available.


The validity of the transcutaneous oxygen tension method in adults.

The transcutaneous oxygen tension (tcPo2) in five healthy subjects and in seven patients was monitored continuously by the technique of Huch, Huch, and Lübbers. The inspired oxygen concentration was varied between 15 and 100%. Once stable tcPo2 recordings were obtained, blood samples were drawn via an indwelling arterial catheter for oxygen tension (Pao2) determination. A comparison between the Pao2 and the tcPo2 values is illustrated graphically. There was a small difference between these values in the healthy subjects, which was attributed to variations in the skin from subject to subject. In the patients, a circulatory factor may have added to differences in the absolute levels. The coefficient of correlation between Pao2 and tcPo2 was in all cases higher than 0.98. In healthy persons, Pao2 may be predicted from tcPo2. In patients, any change in Pao2, due to deterioration or improvement, is manifested in the tcPo2 curve. If one or two arterial blood measurements are performed, low as well as high Pao2 values may be predicted from tcPo2 in patients without gross circulatory impairment.


An improved technique for prolonged arterial catheterization in infants and children.

Arterial catheterization for blood gas analysis and direct monitoring of blood pressure in infants and children can be attended by a variety of complications, which limit its use to short periods of time. An improved technique, consisting of elimination of stopcocks, the use of a continuous flushing system adapted for infants and children, and meticulous care of the system, was used in 57 children whose ages ranged from the neonatal period to 16 years. The mean duration of cannulation was 5.5 days (range, 1-31 days). All but one of the catheters were functional at the time of discontinuation. There were no thromboembolic phenomena, local or systemic infections or accidental bleeding. We feel that our approach to prolonged arterial cannulation can be an extremely valuable aid in the management of critically ill children.


Compliance and dynamic characteristics curves in acute respiratory failure.

Routine measurement of pressure-volume curves of the lungs and thorax in seven patients treated with continuous mechanical ventilation provided supportive evidence for the presence or absence of cardiogenic pulmonary edema, noncardiogenic pulmonary edema, pneumonia, bronchospasm, mucous plugging, intubation of mainstem bronchus, atelectasis, and results of subsequent therapy. Those conditions associated with predominantly airway disease altered dynamic more than static pressure-volume measurements. Those conditions associated with parenchymal lung disease or loss of lung volume generally altered both dynamic and static pressure-volume measurements. The effectiveness of treatment of these diseases could be monitored by their effect on the pressure-volume curve. The determination of pressure-volume measurements are simple, noninvasive, and can be accomplished within minutes. The routine use of these measurements should be one of the monitoring procedures performed in patients treated with mechanical ventilation.


Early recognition and treatment of post-traumatic pulmonary microembolism.

There is a special form of pulmonary dysfunction which most often occurs following massive tissue damage, such as major fractures accompanied by hypovolemia. This syndrome may be appropriately called post-traumatic pulmonary microembolism to distinguish it from other causes of respiratory failure. We believe that pathophysiology is initiated at the time of trauma and consists of platelet aggregation and fibrin deposition in the pulmonary microcirculation caused by release of tissue-thromboplastin products. Whether this acute traumatic pulmonary microembolism will progress to a fully developed post-traumatic pulmonary microembolism with respiratory symptoms depends upon the magnitude and duration of tissue-thromboplastin release and the efficiency of the fibrinolytic system to clear the lungs. The early microembolic effects on the lungs consist mainly of ventilatory derangements with a low ventilation/perfusion ratio; not until a later stage does true shunting of mixed venous blood across fluid-filled alveoli and small airways occur. Frequently determinations of Pao2 and AaDO2 during air breathing ("air-test") to reveal a low ventilation/perfusion ratio is, therefore, preferable to true shunt determinations in patients who may develop this syndrome; caution must be exercised in giving room air to critically ill patients. These ventilatory variables, combined with frequent platelet counts, allow early recognition of post-traumatic pulmonary microembolism.


Acute nonoliguric renal failure in the postoperative patient.

Fourteen patients with acute nonoliguric renal failure have been studied during the past 3 years. The mortality rate was 7% and the complication rate was 21%. Early recognition of the nonoliguric state and its maintenance with adequate volume replacement should decrease the mortality rate in postoperative acute renal failure. Reasons for the decrease in septic complications among this group of patients are not clear, but the absence of septic complications appears to be the major reason for the decreased morbidity and mortality in these patients.


Preliminary studies of energy-rich phosphagens in muscle from severely ill patients.

Preliminary studies on muscle tissue metabolism were made in a series of 18 patients treated in an intensive care unit. In acutely ill patients with circulatory or respiratory insufficiency, there was an increase in muscle lactate content, a decrease in the phosphorylcreatine stores as well as decreased in adenosine triphosphate (ATP) and total adenine (TA) contents. These findings could partly be explained by a relative hypoxia in the muscle but acute hypoxia alone would not account for the decrease in ATP or TA. These changes in the adenylate pool were still more pronounced in patients with prolonged diseases. In this series the ATP content was only 50% of the normal, despite normal lactate content. The reason for the low adenine nucleotide level in muscle tissue is thought to be due primarily to an increased formation and deamination of adenosine monophosphate during hypoxia in combination with a decreased rate of purine synthesis in the liver and/or a decreased capacity for "purine salvage" in the muscle. This itself might, in turn, be mediated by a low energy state in muscle or liver or be due to other metabolic disturbances or tissue damage. It was found that prolonged immobilization without metabolic disturbances did not change the TA content in muscle, while short-lasting severe metabolic acidosis decreased the TA content. A correction of the metabolic disturbance immediately increased the TA content in muscle. A low energy charge potential was found in patients with prolonged diseases, possibly being the cellular expression for the concept of the post-traumatic catabolic state.


Axillary arterial monitoring.

Axillary arterial catheterization for intraoperative and postoperative monitoring was successful in 90% of 87 attempts. Complications occurred in nine patients; there were eight hematomas, one of which was extensive. In the ninth patient, radial pulsations disappeared but returned after the catheter was withdrawn. There were no sequelae in any of these patients.


Airway maintenance in patients with long-term endotracheal intubation.

Long-term endotracheal intubation in seriously ill patients is frequently complicated by nosocomial infection of the tracheobronchial tree, especially with aerobic gram negative bacilli. A further complication is drying of pulmonary secretions unless the medical gases given are humidified. The performance characteristics of humidifying system used in spontaneously breathing, intubated patients is described. This system possesses the potential to decrease infection, provides physiologic humidification without nebulization, and, by avoiding air dilution, allows the administration of a precisely regulated FIO2.


Ventilatory response to carbon dioxide in humans.

Testing ventilatory responses to CO2 is fraught with difficulties in interpretation and, at present, it can hardly be considered suitable for routine evaluation of patients with pulmonary disease. In spite of the seventy years' work since Haldane's introduction of the CO2 response curve, much remains to be learned about the various components of the regulatory system, and for testing chemosensitivity to CO2 in patients with pulmonary disease, methods more direct than measuring pulmonary ventilation are needed for evaluation of the output of the regulatory system.


Measurement of the ventilatory response to hypoxia. A step hypoxia three-minute test.

A step hypoxia method for testing response of patients has been described. It involves a well-trained operator who must observe the patient while monitoring and adjusting alveolar oxygen and CO2 tensions. The advantages of the step test are that the time effects can be examined and that quantitative information in a steady-state can be obtained in a relatively short period of time. It can be done at several different levels of CO2.


Techniques for measuring the responsiveness of the ventilatory apparatus in man in disease.

More complete understanding of the disturbances in the regulation of ventilation in disease must await techniques which can estimate the neural output of the respiratory centers and also the neural inputs. Some of these techniques, such as diaphragmatic electromyography, offer the prospect of clinical usefulness even now and newer techniques, such as mouth occlusion pressure, are promising but have just begun to be evaluated in disease. Despite the limited ability of current techniques to clearly distinguish abnormal central nervous system function of ventilatory control from peripheral mechanical limitations to ventilation, a useful interpretation of clinical tests  of ventilatory responsiveness may be gained by an awareness of the many physiologic and pathogenetic factors which are interposed by disease. These factors may reinforce or diminish both stimuli and response. In chronic disease states, these modifying factors must be identified and evaluated for their role in altered ventilatory responsiveness. Frequently, therapeutic measures can induce substantial effects on these modifying factors, whereas primary disturbances of central nervous system function may be difficult to alter. For the above reasons, tests of ventilatory responsiveness which provide information focussed only on the normality or abnormality of responsiveness to CO2 breathing from measurement of minute ventilation and alveolar PCO2 in an unsteady state, as in the CO2 rebreathing test, may, in a patient, require the addition of tests which allow more complete evaluation of these modifying factors. The state of arterial blood gases, hydrogen ion concentration, bicarbonate concentration, pulmonary function, ventilatory response to exercise, as well as understanding of the state of body temperature, catecholamine secretion, the functional state of the muscles of ventilation, as well as the resistances to ventilation are all a necessary part of the evaluation.


Fiberoptic colonoscopy: the fate of colonoscopic polypectomy sites.

Nine cases of colonoscopic polypectomy followed by colonic resection are reviewed. A properly performed colonoscopic polypectomy produces a mucosal defect resembling a superficial ulceration. Granulation tissue rapidly covers the area, and this, in turn, is eventually covered by normal colonic mucosal epithelium. Mural inflammation is mild and limited to the submucosa, and no demonstrable change occurs in the muscular layers.


Villous adenoma of the colon with severe fluid and electrolyte depletion: report of a case.

A case of severe fluid and electrolyte depletion resulting from a massive villous adenoma of the rectosigmoid colon is presented. The syndrome is discussed, and the often insidious presentation and life-threatening aspects are emphasized.


Nodular mesenteritis: report of a case simulating carcinoma of the sigmoid colon and analysis of its histologic profile.

A case of nodular mesenteritis simulating a carcinoma of the sigmoid is presented. The unusual features of the case are analyzed. Emphasis is placed on the basic histologic reactions seen in nodular mesenteritis and on their possible implications. The questionable relationship to Weber-Christian disease is discussed.


Treatment of paracolostomy abscesses without proximal diverting colostomy: report of two cases.

Two patients had paracolostomy abscesses limited to the abdominal wall. Adequate drainage was obtained surgically using local anesthesia, but wound contamination from the fecal stream continued. Intravenous hyperalimentation and/or elemental diet reduced fecal volume, promoted wound healing and weight gain, and prevented the need for a proximal defunctionalizing colostomy. During follow-up periods of more than ten months, colostomy revision has not been necessary.


Significance of Schistosomiasis japonica in the development of cancer of the large intestine: report of a case and review of the literature.

A 68-year-old man had a tumor in the ascending colon, following schistosomiasis 58 years earlier. Right hemicolectomy was performed. Examination of the specimen showed adenocarcinoma with schistosomiasis japonica. A total of 276 such cases in medical literature were reviewed. There were significant differences between carcinoma with schistosomiasis and ordinary carcinoma in symptoms, age range, sec ratio, and histopathologic findings. These suggest that schistosomiasis induces carcinoma. Chronic inflammation and epithelial proliferation due to intestinal schistosomiasis may be a promoting factor rather than a direct carcinogenic factor in the development of adenocarcinoma of the large intestine.


Submucosal mucous cysts at a colostomy site: relationship to colitis cystica profunda and report of a case.

A unique case of submucosal mucus-containing cysts of the colon occurring at a colostomy site is described. The cysts appear to have been the result of surgery eight years previously, and were due to either implantation of colonic mucosa into the submucosa or entrapment of mucosa following healing of postsurgical ulceration. Because these cysts are identical to the lesions seen in colitis cystica profunda, this case provides additional support for the hypothesis that colitis cystica profunda is an acquired disease, and illustrates that it may occur as a rare complication of colonic surgery.


[Surgical treatment of herniation of a lumbar intervertebral disk in young people (author's transl)].

Among 2755 patients operated on for nerve-root compression there were 38 children and juveniles (aged 11-22 years). Average interval between onset of symptoms and operation was 14 1/2 months and often involved considerable diagnostic effort. 36 of the 38 patients were re-examined an average of 11 years after operation: 15 were free of symptoms, 18 had occasional mild symptoms, two had continuous mild pain and one had occasional severe pain. Re-operation was necessary in six. All patients are able to work. A connection between an accident and the herniation was demonstrated in only two instances.


[Separate evaluation of left and right-sided renal function (author's transl)].

The PAH extraction of the kidneys was determined separately on each side after catheterisation of both renal veins and the femoral artery during PAH infusion in eleven patients with normal or diminished renal function due to bilateral renal disease and in five patients with only one kidney with normal or diminished renal function. A significant positive correlation was found between PAH extraction and inulin clearance and a significant negative correlation between PAH extraction and the log of the serum creatinine. PAH extraction is a suitable method for quantitative evaluation of right and left renal function.


[Idiopathic thrombosis of the superior vena cava (author's transl)].

In contrast to secondary occlusion idiopathic thrombosis of the superior vena cava occurs rarely. With a good collateral flow through anatomically preformed venous channels the clinical picture may have an insidious course obscuring diagnosis. Collateral circulation via upper oesophageal varices is commonly overlooked. Anticoagulants should be given to prevent progression. Surgically vein transplants, by-pass operations, and thrombectomy have been tried. Follow-up in 4 patients shows that even without surgical intervention the prognosis is good despite the danger of haemorrhage from the varices.


[Basic requirements for the development of medical education in Latin America and the Caribbean. Final report].

This is the Final Report of this meeting, which was held in Caracas in January 1976 and sponsored by the Pan American Health Organization and the Pan American Federation of Associations of Medical Schools. The meeting included discussions on fundamental aspects of medical manpower development and recommendations on professional training in health policies, medical practice and care , student enrollment, and the establishment and operation of medical schools. The first part of the Report is a review of international activities in medical education in Latin America and the Caribbean area; standards and minimum requirements of new medical schools; present trends in medical education; influences on professional training; interdisciplinary education and education by fields; preparation of the specialist and the multiprofessional; on-the-scene training in hospitals and elsewhere; institucional structures; and student requests.


[The role of the hospital in the light of the new trends of medical education].

This article sets forth an innovative concept of the hospital's role today in keeping with both contemporary medical education and various national health service needs. After pointing out that the groundwork for a proper integration of training and service goals lies in the principles of medical preparation, the author emphasizes that although health care is provided in the home, in health centers, in outpatients clinics, and in general and specialized hospitals, the future physician's education is primarily the responsibility of universities, medical schools, and departments, which during the clinical phase of training become demonstration clinics atypical of the conditions at the many levels of health services. The combining of teaching and service-essential for the training of a better prepared professional, ready to handle any problem that might arise in the course of his career-is the keystone of this new approach. In other words, the author stresses "early student involvement in all levels of medical care within a particular health region, especially primary care, and a relatively lengthy period of work in direct relationship with the community hospital, supplemented by short periods in specialized hospitals or reference units."


Inhibition of tonic secretion of luteinizing hormone by progesterone in immature female sheep.

The effect of progesterone on the secretion of LH was studied in intact and castrated immature female sheep between 12 and 42 weeks of age. (First spontaneous ovulation occurs between 30 and 50 weeks of age.) Progesterone was administered by means of Silastic capsules inserted SC to achieve circulating progesterone concentrations similar to those found in the adult during the mid-luteal phase of the estrous  cycle (3-4 ng/ml). Prior to treatment, concentrations of circulating LH in intact lambs fluctuated widely (2 to 20 ng/ml) over a 24- to 48-h period. These high and variable levels of serum LH, reflecting a pulsatile secretion of LH characteristic of young female sheep, were not altered by the insertion of empty capsules. Implantation of progesterone-containing capsules, however, resulted in a decrease in serum LH to low levels (less than 0.5 ng/ml) within 4 h. Furthermore, the insertion of progesterone capsules into the same lambs after castration produced an immediate and sustained suppression of LH secretion similar to that which was observed when the ovaries were present. These findings led to the conclusion that in the immature female sheep, protesterone can effect a marked inhibition of LH secretion in the presence or absence of the ovaries. Although it has been postulated that progesterone plays an important role in the negative feedback control of LH secretion in adult sheep during the estrous cycle, it remains to be determined whether this steroid normally plays a physiologic role in the regulation of tonic LH secretion prior to the onset of ovarian cyclicity in the lamb.


The in vivo metabolism of progestins. I. The metabolic clearance rates of progesterone and medroxyprogesterone acetate in the dog.

[3H]Medroxyprogesterone acetate (MPA) was synthesized by selective catalytic tritiation of the delta1-olefinic bond of 6alpha-methyl-17alpha-hydroxy-pregn-1,4-diene-3,20 dione acetate. [14C]MPA was synthesized by acetylation of 6alpha-methyl-17alpha-hydroxy-pregn-4-ene-3,20-dione with [14C]acetic anhydride. These radioactive materials were used to determine the MPA metabolic clearance rates (MCRMPA)and volumes of distribution (VoMPA) in dogs by the single injection technique. The metabolism of progesterone was also studied in the same animals. The MCRMPA (696 +/- 51 l/day) was only one-half that of progesterone (1332 +/- 59). By contrast, the volumes of distribution for the two steroids were similar. The metabolic clearance rates and the volumes of distribution for MPA and progesterone did not change during treatment with amino-glutethimide, a drug which is known to alter steroid metabolism in man.


Thyroid function and insulin secretion from the perfused pancreas in the rat.

The influence of thyroid function on the kinetics of glucose-induced insulin secretion from the isolated perfused rat pancreas has been studied. L-Thyroxine (L-T4) administration did not modify the immediate insulin secretory response of the perfused pancreas to glucose. L-Triiodothyronine (L-T3) treatment as well as propylthiouracil (PTU) treatment decreased the immediate insulin secretory response of the pancreas slightly. Only thyroidectomy (Tx) reduced the immediate secretory response of the pancreas significantly. L-T4 and L-T3 treatment inhibited the late phase of glucose-induced insulin secretion from the isolated perfused rat pancreas, whereas TX and PTU treatment resulted in increased insulin secretion. D-Thyroxine (D-T4) did not affect glucose-induced insulin release from the pancreas. Concomitantly, several parameters indicative of thyroid function were determined in these animals. When changes in body weight, rectal temperature, plasma glucose, plasma cholesterol, and plasma butanol-extractable iodine (BEI) in these rats were compared with the insulin secretory responses, it was evident that experimental hyperthyroidism results in decreased insulin release, whereas experimental hypothyroidism induces increased insulin secretion from the pancreas. The transitions from hypothyroid to euthyroid to hyperthyroid states are accompanied by a steady decrease in glucose-induced insulin release from the rat pancreas. Inhibition of glucose-induced insulin secretion from the pancreas is therefore a specific effect of thyroid hormones.


Adenylyl cyclase activities in ovarian tissues. II. Regulation of responsiveness to LH, FSH, and PGE1 in the rabbit.

We conducted a study to determine whether a decline in the capacity of preovulatory follicles to accumulate cAMP in response to in vitro LH exposure, reported by Marsh et al. (1), is due to direct desensitization of the LH-hCG-responsive adenylyl cyclase (AC) system. Enzyme activity was determined in the absence and in the presence of 10 mug/ml of LH, FSH, and prostaglandin (PG) E1 in homogenates prepared from Graafian follicles dissected before and at various times after rendering them preovulatory either by mating (endogenous LH release) or by injection of hCG (100 IU/3.5-4.5 g rabbit, iv). Both of these treatments resulted in desensitization of the AC to LH and FSH stimulation, so that by the time of ovulation these responses were absent. hCG-induced desensitization was rapid (50% loss of LH-stimulated activity was obtained within 5 min of injection), was dose-dependent, requiring an ovulatory dose; was selective for LH- and FSH-stimulated activity, being without effect on basal and PGE1 as well as NaF-stimulated activities; and was induced specifically by LH (mating) and hCG-FSH and PRL being without effect. Desensitization of follicular AC does not seem to be mediated by PG, for doses of indomethacin that inhibited ovulation did not interfere with the loss of LH responsiveness. The incubation in vitro of dissected Graafian (estrous) follicles with LH (2 h) also resulted in desensitization to LH stimulation and indicated that this phenomenon was due to a direct effect of LH on the follicles and was not mediated by hormones derived from other endocrine structures. Newly formed corpora lutea (CL) in either pregnancy or pseudopregnancy (PSP) developed a new AC system that was highly responsive to LH and less responsive to FSH and PGE1. This new system persisted for the duration of pregnancy and PSP, and became inactive with regression of CL. The prolongation of PSP by hysterectomy was accompanied by the persistence of an active LH-responsive AC system. The injection of ovulatory doses of hCG into 6-day PSP rabbits produced, within 2 h, a 50% desensitization of the luteal AC systems to LH stimulation. After day 10 of pregnancy, the levels of LH-stimulated AC activity in CL and the levels of progesterone in serum, reported by Challis et al. (2), were found to parallel each other, suggesting that this enzyme activity may be a physiologic regulatory step in progesterone synthesis by the normal CL throughout most of the animal's pregnancy. This finding is discussed in the light of compelling evidence that estrogens are luteotrophic in the rabbit.


Adenylyl cyclase activities in ovarian tissues. III. Regulation of responsiveness to LH, FSH, and PGE1 in the prepubertal, cycling, pregnant, and pseudopregnant rat.

In the ovaries of prepubertal rats, responsiveness of adenylyl cyclase (AC) to LH, FSH, and PGE1 is acquired at day 10, coinciding with the appearance of the ability to produce steroids in response to gonadotrophins. The activity and responsiveness of AC on day 11 were similar to those at puberty on day 40 and relatively stable in between. In the follicles of the cycle, the responsiveness of AC to LH and FSH was poor (ca 2-fold stimulation) on metestrus and diestrus, and became high (ca 10-fold stimulation) between 1000 h of diestrus and 1000 h of proestrus. Thereafter, the system slowly became desensitized to LH and FSH, being unresponsive by the morning of estrus. Nembutal injected at 1230 h and again at 1500 h on proestrus blocked ovulation and prevented the decline in LH- and FSH-stimulated AC activity. In the CL of the cycle, the AC was unresponsive to LH on day 1 (estrus), became responsive by the morning of day 2 (metestrus), and maintained responsiveness throughout that day. Thereafter, the responsiveness and basal AC activity declined rapidly. In the CL of pregnancy, LH-stimulated AC was indistinguishable from that of the CL of the cycle during days 1 and 2, then increased steadily until day 9, showing a transient decrease on days 10 and 11, followed by a sharp rise to maximal activity on days 15 and 16. Thereafter, activity declined as parturition approached. In the CL of pseudopregnancy (PSP), LH-stimulated AC was very similar to that of the CL of pregnancy during the first 11 days. Thereafter, it decreased coincident with the termination of PSP. Injections of PRL (100 mug SC twice daily, from metestrus through estrus, and from proestrus through proestrus) or estradiol-17 beta (20 mug, SC at 1230 h on metestrus) resulted in "rescue" of the CL-AC system, which remained at metestrus levels when measured on the days of expected proestrus or estrus. Injections of pregnant mare serum gonadotrophin into prepubertal rats at day 26 (3 IU, iv), induced by day 28 a highly responsive AC system in follicles, with activities equivalent to those found in Graafian follicles on proestrus. By day 29, synchronous ovulation had occurred with a concomitant loss of LH-stimulated AC such as seen in the 1-day-old CL of mature rats. Our results suggest that the LH-sensitive AC may be indicative of the final development of ovulability of the follicles, and that it may correlate with the functional capacity of CL during various reproductive stages of the rat.


Adenylyl cyclase activities in ovarian tissues. IV. Gonadotrophin-induced desensitization of the luteal adenylyl cyclase throughout pregnancy and pseudopregnancy in the rabbit and the rat.

We measured the adenylyl cyclase (AC) activity in dissected CL and the responsiveness of the AC system to LH, FSH, and prostaglandin (PG)E1 at different times following the administration of high doses of hCG or hLH to pseudopregnant and pregnant rats and rabbits. In rabbits, ovulatory doses of hCG promoted desensitization of the AC system in both CL of pregnancy and CL of pseudopregnancy (PSP), but at varying rates. At least a 50% decline in the LH-stimulated AC system was demonstrable 2 h after the hCG injection in CL obtained during PSP and the first 18 days of pregnancy. However, after day 21, AC activity was unaltered at 2 or 24 h after hCG injection, necessitating as much as 72 h for the AC system to become desensitized to LH. It seems that CL in the last third of pregnancy are afforded partial protection from the desensitizing effects of hCG. This protective effect was found not to be conferred upon follicles contained in ovaries after day 21 of pregnancy or upon newly, hCG-induced 3-day-old CL in 24-day pregnant rabbit ovaries. hCG-induced desensitization of CL adenylyl cyclase in rabbits was prevented neither by cauterization of tertiary follicles not by the continued administration of estradiol-17beta (1.5 mug SC twice daily), suggesting that this effect of hCG is due to a direct interaction with the CL, and not due to interruption of the follicular estrogen supply. In rats, the injection of an ovulatory dose of hCG (50 IU SC into prepubertal rats; 50 IU ip plus 50 IU SC into mature rats) also induced desensitization of the AC system in ovaries of superovulated prepubertal rats and in CL of pseudopregnant and pregnant rats. Desensitization of the AC system was not detectable at 2 h, was 30% of total by 6 h, and was complete at 24 h after hCG injection. Both regression of the CL and desensitization of the AC system in CL are induced only by doses of hCG which are ovulatory and not subovulatory. Desensitization of AC appears to precede functional luteolysis, at least in the pseudopreganant rabbit. Thus, the apparent close association between hCG-induced luteolysis and the desensitization of the adenylyl cyclase system in CL would suggest that desensitization may be a marker for luteal regression.


Variations in the response of the thyroid gland of the rat to different low-iodine diets: correlation with iodine content of diet.

Large variations are frequently encountered in the thyroidal responses of rats to commercially available low-iodine diets. The major aim of this investigation was to attempt to correlate these variations with differences in the iodine content of the diets. A method was developed for measuring the iodine content of low-iodine diets which was sufficiently sensitive to discriminate between a diet containing 15-20 ng of iodine per g and one containing 30-40 ng of iodine per g. Large differences were observed between various commercial low-iodine diets in their ability to induce goiter and to affect other indices of thyroid function, and these differences could be correlated with differences in the iodine content. The most severe iodine deficiency occurred in rats that were fed a Remington diet containing 15-20 ng of iodine per g. After 3 months on this diet, thyroid weight increased about 7-fold, thyroid 127I concentration was reduced to about 0.5% of control values, serum thyroxine (T4) was reduced to less than 0.25 mug/100 ml, the ratio of labeled triiodothyronine to labeled T4 was increased to 5.2, and that of labeled monoiodotyrosine to labeled diiodotyrosine was increased to 4.2. Much smaller changes were observed in the rats on the other low-iodine diets, which ranged from 30-40 to about 100 ng of iodine per g. A daily supplement of only 0.2 mug of iodide per day administered to rats on a Remington low-iodine diet produced a significant changes in thyroidal responses. These results suggest that iodine deficiency alone is sufficient to explain the effects of the Remington low-iodine diet and that it is not necessary to postulate the presence of a goitrogen.


Formation of 3,3'-diiodothyronine and 3',5',3-triiodothyronine (reverse T3) in thyroid glands of rats and in enzymatically iodinated thyroglobulin.

It was observed in the present investigation that labeled thyroxine (T4) comprised less than 2% of the total 131I in the thyroids of severely iodine-deficient rats labeled with 131I for 18-24 h, a much lower value than had previously been reported for iodine-deficient rats. This low value was attributable to two factors: 1) the use of a diet low enough in iodine content to produce extreme iodine deficiency, and 2) the use of a paper chromatography system that successfully separates T4 from the minor iodothyronines, 3,3'-diiodothyronine (T2) and 3',5',3-triiodothyronine (reverse T3; T3'). Formation of the minor iodothyronines, while low, becomes appreciable in relation to T4 formation in severe iodine deficiency. In the present study, the formation of labeled T2 was significant only in iodine deficiency, and the highest values were observed in the most severely iodine-deficient rats. In the latter, labeled monoiodotyrosine (MIT) comprised approximately 60% of the total 131I in the thyroid, and the increased formation of T2 could be attributed to the increased probability of coupling between two molecules of MIT. The formation of labeled T3', on the other hand, was significant in thyroids from both iodine-deficient and iodine-sufficient rats. Similarly, in thyroglobulin iodinated in vitro with thyroid peroxidase to varying levels of iodination, the formation of T2 was evident only at lower levels of iodination, whereas the formation of T3' was significant at all levels of iodination. The comparison of relative T3' and T4 formation in enzymatically iodinated thyroglobulin with corresponding values reported for the intermolecular (DIHPPA) model for T4 formation, indicates that the peroxidase model system simulates much more closely the relative formation of T3' and T4 seen in vivo.


Nutrition and somatomedin. I. Effect of fasting and refeeding on serum somatomedin activity and cartilage growth activity in rats.

The relationship between nutrition, somatomedin, and growth was studied in young male rats which were fasted for 72 h, and then refed. Cartilage growth activity was measured by the incorporation of SO4 by costal cartilage incubated in vitro. Serum somatomedin activity was measured by the ability of sera to stimulate the incorporation of SO4 in vitro by cartilage from hypophysectomized rats or normal young pigs. Cartilage growth activity was unchanged after 24 h of fasting, but decreased significantly to hypopituitary levels after 72 h. The decrease in cartilage growth activity could not be attributed to a decrease in the ability of cartilage to respond to somatomedin, since fasted rat cartilage incubated in vitro had significantly greater stimulation from the addition of normal rat serum (normal somatomedin) than from the addition of hypophysectomized rat serum (low somatomedin). A decrease in serum somatomedin preceded the decrease in growth activity; somatomedin was significantly decreased after 24 h of fasting, and fell to hypopituitary levels after 72 h of fasting. The decrease in somatomedin could not be attributed to growth hormone deficiency, since treatment with bGH did not prevent the fall in somatomedin. The direct addition of fasted rat serum to normal rat serum did not inhibit the somatomedin activity of the normal serum. The refeeding of 72h-fasted rats was associated with an increase in serum somatomedin which was significant after 6 h, and comparable to control levels after 24 h of refeeding. The increase in somatomedin was followed by an increase in cartilage growth activity, which was significant after 12 h, and comparable to control levels after 48 h of refeeding. We conclude that adequate food intake appears to be required for the maintenance of normal levels of somatomedin; the processing of nutrients may modulate the generation of somatomedin.


Partial purification of a progesterone-inducible messenger RNA (avidin) from hen oviduct.

The messenger RNA (mRNA) for avidin, which represents less than 0.05% of the total cellular proteins, was partially purified from hen oviduct, and the presence of avidin mRNA was shown to depend upon prior stimulation by progesterone. A total nucleic acid extract was subjected to oligo (dT)-cellulose chromatography, followed by Sepharose 4B chromatography, preparative agarose gel electrophoresis, and sucrose gradient centrifugation. The relative purity of each preparation was assessed by translation in a wheat-germ system; avidin messenger RNA activity was measured by specific immunoprecipitation of synthesized proteins. Avidin mRNA was separated from the bulk of the total messenger RNA activity of the oviduct and from all ribosomal RNAs to produce greater than a 1000-fold enrichment of avidin mRNA activity compared with total cellular RNA. Based on the translation assay, the most highly purified fraction contained about 2.5% avidin messenger RNA. Avidin mRNA activity was absent in partially purified mRNA obtained from estrogen-stimulated chick oviducts, but was detected in oviducts following progesterone administration.


Morphine inhibition of ovulation: reversal by naloxone.

The effect of naloxone (N-allylnoroxymorphone), a narcotic antagonist, on the morphine blockade of ovulation was studied. Female rats were treated with morphine (50 mg/kg) at the critical period, resulting in ovulatory blockade. The administration of naloxone (0.5 mg/kg) effectively reversed the anti-ovulatory effect of morphine. The antagonist reversed the morphine effect when given 1 hour before (75% reversla), simultaneously (75% reversal), and up to 3 hours after morphine treatment (63% reversal). The number of ova shed per animal was not affected by naloxone treatment with or without morphine. When the blockade of ovulation occurred in animals treated with both naloxone and morphine, uterine distension was present in 85% of the animals on the day of estrus.


Cytosol androgen binding in submandibular gland and kidney of the normal mouse and the mouse with testicular feminization.

Androgen binding was investigated in the cytosol of the submandibular gland and the kidney from normal mice, mice with testicular feminization (Tfm), and carriers of the Tfm gene. In both tissues from normal mice an androgen-binding complex was observed from birth throughout life that could not be detected in Tfm animals at any age. This complex was precipitated at 35 and 40% saturation with ammonium sulfate in the kidney and the submandibular gland, respectively, and had an approximate sedimentation coefficient of 8S in the submandibular gland and 10S in the kidney. In both tissues of the normal female, the apparent dissociation constants (Kd) for testosterone and dihydrotestosterone were about 1 nM, and the binding capacity averaged 20 fmol-mg protein-1. The number of binding sites in preparations from Tfm carriers was intermediate between that in the Tfm and the normal female . In 0.5M KCl the 8S receptor of normal submandibular gland sediments at about 3S, and the 10S receptor of normal kidney sediments at about 4.5S. In the submandibular gland, binding of approximate 3S size was also observed. The latter was present in Tfm animals as well as in normal mice, it precipitated at 70% saturation with ammonium sulfate, and it was detectable from birth. In the kidney the only low molecular weight binding for androgen was about 4.5S in size.


Serum beta-N-acetylglucosaminidase in patients with symptomatic porphyria.

Studies in 30 male patients with symptomatic porphyria reveal an increased activity in the serum of the lysosomal enzyme beta-N-acetylglucosaminidase (EC 3.2.1.30) as compared with a control group of 33 healthy males. Enzymatic activity is higher in the active stage of the disease (with fresh skin lesions) than in patients found in remission. A high degree of correlation has been detected between the activity of beta-N-acetylglucosaminidase in the serum and uroporphyrin in the urine, and the total plasma porphyrins. The increased activity of this enzyme in the serum indicates that the lysosomes participate in the pathogenesis of this disorder. Further studies are warranted for the complete elucidation of the clinical significance of this parameter.


Pyruvate kinase isozymes among human organs and blood cells.

In extracts of human tissues only three different pyruvate kinases were demonstrated by acetate gel electrophoresis. Treatment with reduced glutathione resulted in an alteration of electrophoretic mobility of extracts from kidney and testis. The existence of interconvertible forms of M2 pyruvate kinase (PK) was suggested. Lymphocytes, polymorphonuclear cells, platelets were M2 type PK. An electrophoretic slow form was demonstrated in myeloblasts and lymphoblasts.


Heterogeneity of human erythrocyte acetylcholinesterase. Individual variation revealed by DEAE-cellulose chromatography and polyacrylamide gel disc electrophoresis.

Acetylcholinesterase (EAChE; acetylcholine acetyl hydrolase, EC 3.1.1.7) was prepared from the erythrocyte membrane of Chinese adult males, and solubilised with 1% Triton X-100 in 20 mmol/l phosphate buffer, pH 7.4. Chromatography of the preparation on DEAE-cellulose, using a linear gradient of increasing NaCl concentration, yielded four reproducible elution patterns with differing peaks of enzyme activity. On the basis of the number and position of the enzymatically active peaks, the individuals could be grouped into four types: type I: with 4 peaks of activity, EAChe 1, EAChE 2, EAChE 3, EAChE 4; type II: with 3 peaks of activity, EAChE 1, EAChE 3, EAChE 4; type III: with 3 peaks of activity, EAChE 1, EAChE 2, EAChE 4; type IV: with 3 peaks of activity, EAChE 1, EAChE 2, EAChE 3. Each enzyme entity could be eluted in the similar position on rechromatography with loss of activity. When the same samples were subjected to disc electrophoresis on 5% polyacrylamide gel at pH 8.6, three different repeatable patterns were observed. A distinct band (Ch4) at the origin, containing a largest proportion of the enzyme activity, was present in all the samples. One group contained three additional bands of activity Ch3, Ch2, Ch1, while the other two groups had either Ch2 and Ch1 or Ch3 and Ch1 in addition to the Ch4 band. No correlation was apparent between individuals typed by DEAE-cellulose chromatography and those typed by disc electrophoresis; further no correlation between either of these types and blood group was apparent.


Apparent co-operative effect of hydrogen carbonate (HCO-3) on pigeon kidney pyruvate carboxylase.

Kinetic methods have been used to determine the interrelationship between HCO-3, pyruvate and acetyl-CoA and their effect on pigeon kidney pyruvate carboxylase (pyruvate: CO2 ligase [ADP], EC 6.4.1.1). HCO-3 shows a negative co-operative effect (biphasic kinetics with two different Km values). Pyruvate influences the attachment of HCO-3 to this enzyme. The same has been shown for acetyl-CoA. Contrary to the results of other investigators no co-operative effect was seen with pyruvate even at different concentrations of acetyl-CoA. HCO-3 itself shows hardly any effect on the homotropic positive co-operativity (sigmoidal kinetics) of acetyl-CoA. The negative co-operative effect of HCO-3 could not be removed even at saturating concentrations of pyruvate and/or acetyl-CoA, which is also supported by the n and Rs values. The results of this communication bring out differences between pigeon kidney pyruvate carboxylase and pyruvate carboxylase from other sources. It is also suggested that there may be different allosteric and regulatory sites for acetyl-CoA, HCO-3 and pyruvate.


Separation of beta-galactosidases and beta-glucosidases from human liver.

Various fractions obtained from normal human liver homogenates by gel chromatography and selective adsorption and elution from insolubilized concanavalin A were compared as to their beta-galactosidase and beta-glucosidase activities. The high-molecular-weight acidic beta-galactosidase form was converted into the smaller major form by sodium dodecyl sulfate treatment. Electrophoresis and electrofocusing on acrylamide slabs revealed, in addition to the two major isoenzyme forms (acid and neutral), another five minor bands with enzymatic activity.


Sensitivity of carboxylesterases of rat serum to diethyl-p-nitrophenyl phosphate.

The effects of varying concentrations of the organophosphorus inhibitor E600 (diethyl-p-nitrophenyl phosphate) have been studied on the hydrolysis of a homologous series of n-alkyl aliphatic esters of alpha-naphthol by carboxylesterases of whole rat serum and by an esterase isozyme purified from the latter. The results indicate a regressing organophosphate susceptibility of the isozyme with progressively higher substrates. Inhibitor profiles of the whole serum, however, are more complex and do not exhibit any definite pattern in response to a sequential variation in the acyl carbon chain length of the esters. Both the isozyme and whole serum manifest an unusually high degree of organophosphate sensitivity towards substrates bearing odd number of carbon atoms in the acyl chain.


New pathway of conversion of pyridoxal to 4-pyridoxic acid.

The only enzyme demonstrated so far to catalyze the formation of 4-pyridoxic acid, the final excretory product of vitamin B6, was aldehyde oxidase. In this paper we have presented an evidence that another enzyme, NAD+-dependent aldehyde dehydrogenase, is capable of catalyzing this reaction. Rat mutants with high, low and no aldehyde oxidase activity excrete the same amount of isotope after a single injection of 3H-pyridoxol in a 12-day experiment; 4-pyridoxic acid is also present in the urine of animals without aldehyde oxidase activity. There is no correlation between the proportion of the excreted acid and the amount of pyridoxal excreted, after the injection of a single dose of the aldehyde form. The Km values for pyridoxal and NAD+, at pH 9.6, have been found to be 75 and 260 mumol/l, respectively. NAD+-dependent pyridoxal dehydrogenase was partially purified from the rat tissues, and the following specific enzyme activities (nmol-min-1-mg-1 protein) were found: red blood cell 71.5 +/- 3.0, intestine 64.9 +/- 9.0, muscle 61.4 +/- 1.6, brain 39.5 +/- 6.0, liver 34.4 +/- 3.3, kidney 21.1 +/- 5.6, heart 18.8 +/- 0.9, and lung 6.5 +/- 2.0. This is believed to be the first report demonstrating pyridoxal oxidation, catalyzed by an NAD+-dependent aldehyde dehydrogenase.


A comparative study of the Bessey method and Hausamen method for serum alkaline phosphatase determination.

The methods of Bessey et al. and Hausamen et al. for serum alkaline phosphatase determination were compared. Determinations were carried out using sera from healthy blood donors and sera from patients suffering from different hepatobiliary diseases. A high reproducibility of values obtained using both methods was noted. The sensitivity of the method of Hausamen et al. is about four times greater than that of the method of Bessey et al., even though the former method employed a lower reaction temperature. A high degree of correlation exists between the two methods and the data reported indicate that both methods are completely valid.


Glucose-6-phosphate dehydrogenase deficiency in a dog.

After screening 3,300 dogs, one animal with a mild deficiency of erythrocyte G6PD was detected. Although it had several clinical problems for 2 months, no abnormality could be directly attributable to the reduced enzymatic activity. Biochemically the mutant was electrophoretically slower but within the normal range for Km-G6P, Km-NADP, use of 2-dG6P and deamino NADP, pH optimum, and heat stability.


Congenital hemihypertrophy and malignant giant pheochromocytoma - a previously undescribed coincidence.

This is apparently the first report on connatal hemihypertrophy with malignant pheochromocytoma. The coincidence of hemihypertrophy with other diseases, particularly neuroectodermal dysplasias on the one hand and the frequent association of neuroectodermal dysplasias with pheochromocytoma on the other, are emphasized. Furthermore, basically known particularities of this case as malignancy of the tumor, the unusual size of the tumor in children, and the normal catecholamine levels in serum as well as the normal excretion of vanillylmandelic acid are discussed.


Clinical and radiologic aspects of vesicoureteral reflux in children.

The findings of 300 cases of vesicoureteral reflux are reported. Girls were affected 3 times more frequently than boys. The reflux was unilateral in 61% with a strong preponderance of the left ureter. Two hundred and seven children presented with a so-called complete reflux, the contrast material being dected in the ureter and in the pelvicalyceal system at the same time. Almost one third of the children exhibited some changes of the pelvicalyceal system and every 4th patient had serious changes in the upper urinary tract and kidneys. According to the severity of the changes in the ureter, the pelvicalyceal system, and the kidney tissue, 4 types of reflux are differentiated. Typed 1 and 2 were treated successfully with conservative therapy alone, while types 3 and 4 responded only to surgical correction. In 61 cases followed closely for at least 8 months, 28 cases were cured.


ALPHA-Amylase activity in sweat and serum of patients with cystic fibrosis of the pancreas.

The hypothesis by Doggett and Harrison, according to which alpha-amylase is the pathogenic factor of the exocrinopathy in cystic fibrosis (C.F.), is investigated. No elevation of alpha-amylase in sweat and serum of C.F. patients, as compared with controls of similar age, is observed. It is concluded that the "C.F. factor" cannot be identified with alpha-amylase.


Steatorrhea, a simple and rapid method of diagnosis.

A simple and rapid method for the diagnosis of steatorrhea is described. The method is based on the assessment of the difference of specific gravity and lipophilic property between a normal stool and that in steatorrhea, using a benzene-NaBr system. The stool samples are dried, pulverized, and then investigated. Steatorrhea is defined either as a fat or more in a 24-hour sample. Stool samples of 71 infants and children were examined. Among these were 23 healthy subjects, 10 with upper respiratory tract infections, and 6 with pneumonia. A further 31 children had celiac disease, 9 of them were on a gluten-free diet, and one child had cystic fibrosis. The procedure described renders single stool samples suitable for the assessment of steatorrhea. As a screening test the method proved to be rapid and accurate in the diagnosis of steatorrhea.


Effects of ADH on the activity and function of the renin-angiotensin-aldosterone system in infants and in children.

In babies ranging in age from 1 to 25 weeks and in children between 1 and 14 years, plasma renin activity and urinary aldosterone activity were determined in relation to urinary sodium excretion. A reciprocal correlation was found demonstrating that the hyperactivity of the renin-angiotensin-aldosterone system is stimulated in infants by a low sodium intake. A second stimulus was observed in the influence of the hypothalamo-neurohypophyseal system, when the plasma renin activity was suppressed by administration of antidiuretic hormone and sodium excretion increased due to a decreased aldosterone activity. Our study suggests that there exists a feedback between the renin-angiotensin-aldosterone system and ADH release and that this feedback plays an important role in the regulation of water and electrolyte balance in the young infant.


Fatty acids incorporation into human adipose tissue in hypertriglyceridaemia.

The fatty acid and glucose incorporation into glycerides and glycerol release from adipose tissue were determined in a middle-aged population of 109 men and 41 women. 43 men and 19 women were normolipidaemic. The same analysis was also carried out in 13 male and 9 female normolipidaemic students. Needle biopsy specimens of adipose tissue were incubated in vitro in an albumin medium containing 3H-fatty acids and 14C-glucose. After two hours of incubation values for fatty acid and glucose incorporation were calculated from the incorporation of 3H-activity into the fatty acids and 14C-activity into the glycerol moiety of extracted glycerides. The mean values for fatty acid incorporation were lower in all types of hypertriglyceridaemic subjects (II B, III, IV and V) than in the normolipidaemic control subjects. In the male hypertriglyceridaemic population 36% had values for fatty acid incorporation below the 5th percentile of the normolipidaemic group and 14% had values below the lowest normal value. The rate of fatty acid incorporation was negatively correlated with the serum triglyceride concentration. This correlation remained unchanged when partial correlation was performed when the influence of body weight was eliminated. Fatty acid and glucose incorporation correlated positively. Incorporation of glucose behaved in the same way as described above for incorporation of fatty acids. Glycerol and fatty acid release was the same in the normo- and hypertriglyceridaemic groups. It is likely that the removal of plasma triglycerides from blood requires hydrolysis of triglycerides to fatty acids and the subsequent removal of the fatty acids. The hypothesis has been formulated that when the former process is normal, a defect of fatty acid removal (a low rate of fatty acid incorporation into glycerides) may be responsible for an impaired removal of plasma triglyceride-fatty acids. A low rate of fatty acid incorporation may contribute to the development of hypertriglyceridaemia, according to this hypothesis.


Compensatory mechanisms for the severe anaemia caused by haemoglobin Hammersmith.

A severely anaemic, but asymptomatic patient, who is a heterozygous carrier of haemoglobin Hammersmith (beta42 (CD1) phenylalanine - Serine), has been studied to elucidate the mechanisms resulting in physiological compensation for the anaemia. Four factors have been investigated: the oxygen affinity of her blood, the cardiac output at rest and during exercise, the blood gas indices, and pulmonary function. It was found that due to the presence of Heinz bodies within the erythrocytes, the level of functional, haemoglobin was considerably less (50 g/l) than that measured by standard methods (87 g/l). In addition a moderate degree of arterial hypoxaemia (arterial oxygen tension = 10.7 kPa (80.4 mmHg) was present which could not be explained on the basis of abnormal pulmonary function. Both of these factors would result in tissue hypoxia, but the finding of consistently normal oxygen tensions ('mixed' venous oxygen tension = 5.4 kPa (40.3 mmHg) in blood obtained from the right atrium, suggested that hypoxia was not present. This was explained by a decreased whole blood oxygen affinity (P50 = 4.6 kPa (34.5 mmHg) at pH 7.4) and an increase in the cardiac index (5.3 L.min.-1m-2). The latter was the result of an increased stroke volume (125 - 135 ml), the heart rate being normal (63/min.). During moderate exercise, further increases at cardiac output were brought about by a change in heart rate alone. It has been calculated that the decrease in whole blood oxygen per se could not account for adequate tissue oxygenation. This is confirmed by the finding of an increased cardiac output in this patient. It is suggested that in any severe haemolytic anaemia, even if the whole blood oxygen affinity is low, cardiac output is probably increased to achieve complete physiological compensation.


Oral versus intravenous administration of butylbiguanide: effect on oral glucose tolerance in normal humans.

1. The effect of oral and intravenous administration of butylbiguanide on the oral glucose tolerance test was investigated in 12 normal human volunteers. Orally administered butylbiguanide lowered the oral glucose tolerance curve and the corresponding serum insulin values, whereas intravenously injected butylbiguanide had no effect. 2. The lactate/pyruvate ratio determined 180 min. after glucose ingestion increased after oral butylbiguanide administration. No effect was observed after intravenous administration. 3. The decrease in serum phosphate levels observed after oral glucose loading was not influenced by butylbiguanide administered by either route. In addition, no effect of this drug was observed on fasting levels of glucose, insulin, phosphate, bicarbonate, lactate and pyruvate. 4. These results are compatible with recent observations that biguanides inhibit active transport mechanisms in the intestine. In addition, the effect of biguanides on blood levels of glucose metabolites is discussed with respect to their known action on oxidative phosphorylation.


Partial purification of human renin substrate.

A two-step purification method is described for the preparation of renin substrate from human plasma. Pooled plasma from women on oral contraceptives is used for the purification. The overall yield of renin substrate is 57%, with a twenty-fold purification. The specific renin substrate content of the preparation, as determined by enzymatic degradation with an excess of human renin, is 2 mug angiotensin I per mg protein. The product has a very low endogenous renin activity and is free from angiotensinase activity. An additional purification step involving affinity chromatography is described. In pilot studies a renin substrate yield of 37% has been achieved, with a hundred-fold purification. The final product has a specific renin substrate content of 10 mug angiotensin I per mg protein. The preparation contains up to 12 different plasma proteins, nine of which have been identified and quantitated.


The effect of generalized hypoxia upon flow and composition of cardiac lymph in the dog.

Generalized hypoxia lasting 60 seconds more than doubled the cardiac lymph flow in dogs. The number of erythrocytes per mm3 of cardiac lymph increased by about 300%. However, there was no change in total protein or in the concentrations of different lipids following hypoxia. Thus, the transfer of erythrocytes across the myocardial interstitium increased by a factor of ten, and proteins and lipids by 150%. An increase of the capillary surface area probably explained the increased lymph flow. Permeability for macromolecules through the endothelial cells was not increased, since the selectivity for different lipids did not change. The increased transfer of erythrocytes may be explained by an increased permeability through intercellular junctions. The triglyceride content of thoracic duct lymph decreased by about 60% in the corresponding period, but no changes in flow or permeability were observed.


Effects of haemodialysis on fractional intestinal absorption of calcium in uraemia.

Fractional intestinal absorption of calcium was measured in 41 haemodialysed patients 4 hours after an oral dose of 47 Ca. Fractional intestinal calcium absorption was 40.3 +/- 1.9% (SEM) when measured 10 to 12 hours after a haemodialysis session (dialysate calcium concentration: 1.75 mmol/litre). This value was significantly lower (p less than 0.001) than that in 26 healthy controls (56.8 +/- 1.8%) and higher (p less than 0.05) than that of 35 patients with chronic renal failure treated conservatively (34.5 +/- 2.1%). In 17 patients, fractional intestinal calcium absorption was measured just before and just after a dialysis session. Pre-dialysis fractional intestinal calcium absorption (33.7 +/- 3.0%) was not significantly different from fractional intestinal calcium absorption in uraemic patients treated conservatively, while after dialysis fractional intestinal calcium absorption had increased significantly to 42.0 +/- 2.6% (p less than 0.001). It is suggested that the transient increase in fractional intestinal calcium absorption observed after dialysis could be related to dialysis induced volume depletion rather than to a vitamin D-dependent mechanism.


Purification and catalytic properties of "thermostable" fumarase from Bacillus stearothermophilus NU-10 and Thermus X-1.

Fumarase (L-malate hydro-lysase E.C.4.2.1.2) was purified from the thermophilic bacteria Bacillus stearothermophilus NU-10 (optimum growth temperature 62-63 degrees C) and Thermus X-1 (optimum growth temperature 70 degrees C). The furmarase from Thermus X-1 is slightly more thermostable and has an "optimum" catalytic reaction temperature of 83 degrees C as compared to 81 degrees C for the B. stearothermophilus enzyme. Increased thermostability of these fumarases permitted an examination of the properties of the enzyme catalyzed reaction at temperatures higher than had previously been possible with the furmarases from mesophilic bacteria or higher plant and animal sources. Beyong the observed thermostability of the thermophilic fumarases, the catalytic properties of thermophilic fumarases were very similar to those observed with bacterial fumarase or the well characterized pig heart fumarase (effect of temperature on substrate affinities, pH optimum, substrate inhibition by fumarate, and Haldane relationship). These similarities suggest that thermophilic enzymes may be useful in the general study of enzyme reaction mechanisms.


Chemical, physical and enzymatic comparisons of formyltetrahydrofolate synthetases from thermo- and mesophilic Clostridia.

Formyltetrahydrofolate synthetase from the mesophiles Clostridium cylindrosporum, C. acidiurici, and C. formicoaceticum and the thermophile C. thermoaceticum have been purified to homogeneity, the first two by Rabinowitz and Himes and their coworkers and the latter two by ourselves. The physical properties of these proteins are very similar. All four enzymes are tetrameric and all are activated by NH4+ or K+, and the mechanism of this activation always involves a decrease in Km for formate. The enzyme from C. formicoaceticum is more thermostable and has a higher temperature optimum than the C. cylindrosporum or C. acidiurici enzymes and the C. thermoaceticum enzyme is the most thermostable. Comparisons of the amino acid compositions indicate possible correlations between thermostability and an increased content of isoleucine, arginine and tryptophan and a decreased content of phenylalanine and aspartic acid. Both of the less thermostable enzymes dissociative above 37 degrees if NH4+ or K+ are removed, but neither of the more stable enzymes do. In 25% D2O, the C. formicoaceticum enzyme is destabilized at elevated temperatures, relative to the C. thermoaceticum enzyme. It is possible that stronger hydrophobic interactions between subunits are responsible for increased thermostability in these enzymes.