Search

Multiplication-stimulating activity (MSA) for chicken embryo fibroblasts was purified from serum-free medium conditioned by the growth of a line of rat liver cells (CRL), The biological activities of purified CRL MSA for chicken embryo fibroblasts were compared with those of calf serum to determine which activities are important for the stimulation of DNA synthesis and mitosis. In a balanced salt solution, only glucose and amino acids were needed in addition to purified CRL MSA to stimulate DNA synthesis maximally. Purified CRL MSA stimulated the rates of uptake of glucose and α-aminoisobutyric acid. Only the stimulation of the rate of glucose uptake appeared to be a primary response to purified CRL MSA since the stimulation was not inhibited by actinomycin D or cycloheximide. The stimulation of the rate of uptake of α-aminoisobutyric acid was inhibited by actinomycin D. CRL MSA differed from calf serum in its inability to commit cells irreversibly to synthesize DNA after the removal of CRL MSA and in its lack of the ability to stimulate the migration or prolong the survival of chicken embryo fibroblasts. Comparative studies indicated that purified CRL MSA had functional similarities to insulin and somatomedin. CRL MSA may be representative of a family of small polypeptide hormones having insulin-like activity which are involved in the control of cell multiplication.

Carbon dioxide, water and vascular space were measured in the hind limb of the dog, with blood and plasma perfusion, before and after the administration of acetazolamide. Inhibition of carbonic anhydrase by acetazolamide resulted in a decrease in carbon dioxide space from greater than water space to similar to vascular space. This observation is consistent with the presence of carbonic anhydrase in the extravascular compartment. Its presence in this location could act to facilitate carbon dioxide transport.

Secondary cultures of human diploid fibroblasts were used to study the effect of pH on cellular proliferation. In nonconfluent cultures, the growth rate at pH 7.1 was similar to that at pH 7.7 regardless of serum concentration. However, the saturation density achieved at pH 7.7 at any serum concentration was always 2–4 times that achieved at pH 7.1, although the greatest differences in saturation density were observed at the higher serum levels. The results suggest that the effect of pH on saturation density is due to two factors. One, cells at pH 7.1 seem to have a greater ability to undergo contact-inhibition than at pH 7.7, independent of any serum functions; and, two, confluent cells in medium at pH 7.1 are somewhat less sensitive to growth stimulation by increasing serum concentration than are confluent cells raised in medium at pH 7.7.

Summary. Determinations of the pyruvate and lactate content of capillary blood during the steady state of heavy muscular work showed, that both substances are found in increasing amounts with increasing severity of work. At cessation of work the lactate concentration immediately began to decrease, whereas the pyruvate concentration showed a further increase with its maximum 3–5 minutes after cessation of work, before it began to decline. The ratio lactate pyruvate consequently has different values during pyruvate work and at different times after work. It is assumed that the increased amount of pyruvate found in the blood during and after work is formed by the oxidative elimination of the lactic acid, We are greatly indebted to dr JENS HALD of the Biological Laboratories of Medicinalco Ltd. who kindly provided us with hard to get chemicals and valuable advice.

The ability of human blood to acetylate p-aminobenzoic acid, determined in vitro, varied directly with the ambient temperature to which the subject was exposed before the blood was drawn. This was demonstrated by 135 determinations of the acetylating ability of the blood of 49 subjects performed over a period of 3 years, and also in acute experiments in which subjects were exposed to 6 and 37 C for up to 2 hr. Variations in the acetylating ability of blood may reflect the activity of metabolic mechanisms involved in thermal homeostasis. aromatic amines; p-aminobenzoic acid; cold; heat acclimatization; (blood) enzymes; weather; environment Submitted on September 11, 1962

In anesthetized and nephrectomized dogs, acute respiratory acidosis was found to raise the arterial plasma osmolality: the latter exhibited a linear dependency toward Pa CO 2 over the range of 40–150 mm Hg ( Δ Osm/ Δ P CO 2 = 0.17 mOsm/mm Hg·kg H 2 O). This indicates that a P CO 2 rise entails an overall increase of body fluid osmolality, the major part of which reflects apparently the filling of whole-body CO 2 stores. The possibility of minor osmotic redistributions of body water in connection with this phenomenon involves a disproportionately large uncertainty as to the magnitude of the transmembrane cationic exchanges generally assumed to contribute to extracellular buffering in respiratory acidosis. The finding of this new link between the acid-base balance and the water-and-electrolyte equilibrium in the organism may be of interest for the interpretation of some systemic effects of acute respiratory acidosis.

Summary A case of galactosaemia in a 5-month-old infant was studied by paper chromatography. The pronounced amino-aciduria which was present, diminished when the patient was placed on a milk-free diet. Amino-aciduria in galactosaemia is presumed to be of renal origin.

Freshly caught migrating lampreys were placed in 50% sea water and their method of osmoregulation was analysed. Some osmoregulated more successfully than others. Water balance is maintained by a mechanism involving the drinking of large quantities of water (up to 99·5 ml/kg/day). Sodium, potassium and chloride are absorbed by the intestine (often against a concentration gradient) with the subsequent uptake of water. Divalent ions are not readily absorbed by the intestine and there is some evidence for the secretion of magnesium and sulphate into the gut lumen. The limited urine flow (up to 6·2 ml/kg/day) is used for the excretion of calcium, magnesium and sulphate in high concentrations, but the urine is never hyperosmotic to the blood. The urinary excretion of monovalent ions is not sufficient to eliminate those entering by the intestine and extrarenal excretion at the gills must presumably occur. The breakdown of this osmoregulatory mechanism during the anadromous migration involves: an increase in the permeability of the integument to water, a breakdown of the swallowing mechanism which is not dependent upon the occlusion of the alimentary canal, a reduction in the ability to absorb monovalent ions and water from the ingested 50% sea water, and a loss in the large mitochondria-rich ‘chloride output cells’ of the gills. The similarities between the mechanisms of ‘marine’ osmoregulation of lampreys and teleosts are discussed in terms of the evolution of the two groups, and it is concluded that almost identical osmoregulatory mechanisms have evolved independently.

The rate of equilibration of lactate and pyruvate between plasma and red cells has been studied during asphyxia and following addition of sodium lactate in vivo and in vitro. In the resting, well-oxygenated guinea pig, the mean plasma/red cell ratio of lactate was 1.55 and that of pyruvate 2.47. During asphyxia, the plasma/red cell ratio of lactate rose and that of pyruvate fell, indicating a delay in equilibration. Incomplete equilibration affected particularly the lactate/pyruvate ratio in the two compartments. Infused neutral sodium lactate penetrated the red cells at a rate comparable to that observed following endogenous release of lactic acid during acute asphyxia. In vitro at pH 6.8@#X2013;7.4 at 38 C, the time to 50% equilibration of lactate between plasma and cells of human blood was less than 2 min. It is concluded that during acute asphyxia and resuscitation whole blood values of lactate and pyruvate do not bear a constant relationship to those of plasma. lactate/pyruvate ratio Submitted on March 16, 1964

1. Ethanolamine phosphatide and rat chylomicra accelerate plasma coagulation in the presence of Russell's viper venom. 2. Serine phosphatide and inositol phosphatide do not show this activity. 3. It is suggested that the coagulant action of chylomicra may be due to their ethanolamine phosphatide content.

1. A method is described for measuring the accumulation of K at 37°C. by washed human red cells in glucose-containing systems in which the pH is kept constant, the K content of the cells being compared with that of the cells of systems which contain no added glucose but which are otherwise treated similarly. 2. In systems containing added glucose, the accumulation of K begins shortly after the cells have been warmed to 37°C., proceeds to a maximum which is reached after about 10 hours, and then falls exponentially. The maximum rate of accumulation is found during the first 3 hours. In systems which contain no added glucose, the K content of the cells appears to decrease exponentially with time for about 18 to 24 hours; thereafter the K content of the cells may decrease rapidly and the systems may show considerable hemolysis. Sometimes a small accumulation effect is observed during the first 2 to 3 hours; this may be the result of the washed cells not having been completely freed of glucose. 3. The accumulation process proceeds at its maximum rate at pH 7.4 to 7.6, which is also the pH at which the K loss from the red cells is at a minimum in systems containing no added glucose. 4. When red cells are stored at 4°C. for increasing lengths of time, the storage is accompanied by increasing K loss and the maximum rate of accumulation observed when the cells are warmed to 37°C. at first becomes greater. If the storage at 4°C. is continued for more than 3 to 4 days, the rate of the accumulation which occurs at 37°C decreases again, the accumulation mechanism showing progressive deterioration with time even at low temperatures. This deterioration has a counterpart in the progressive deterioration (deduced from the analysis of the curves relating K content and time) of the accumulation mechanism with time at 37°C. 5. The accumulation of K occurs at a maximum rate when the concentration of glucose in the system is between 50 and 200 mg./100 ml. Its temperature coefficient over the range 27–37°C. is 2.4. In the presence of glucose and at pH 7.6, accumulation of K takes place from isotonic mixtures of KCl and LiCl or of KCl and CsCl only a little less actively than from mixtures of KCl and NaCl; i.e., the accumulation of K under optimum conditions seems to be an active process which is at least partly independent of the excretion of Na.

The effect of medroxyprogesteone acetate (MPA) on fasting growth hormone (GH), arginine tolerance tests, oral glucose tolerance tests, and mean 24-hour GH concentrations (MGHC) was studied in 11 active acromegalic patients. The patients received 10 or 20 mg of oral MPA 4 times/day for 5-12 months and were evaluated before treatment and at 1-week, 2-month, and 5-month intervals following therapy. 3 patients had a significant decrease in MGHC after 5 months of therapy while 5 patients demonstrated significant increases as early as 1 week posttherapy (p less than .001 for both). 1 week following MPA therapy only 1 of 4 patients initially responding to arginine continued to respond to the infusion. 2-5 months posttherapy the responses were similar to the pretreatment values. Plasma GH response to glucose ingestion did not change after MPA administration. Clinical improvement was noted, especially in the patients who had accompanying decreases in their plasma GH levels. No abnormality in protein bound iodine, thyroxine, cholesterol, triglyceride, folic acid, glucose tolerance, or insulin was found during 5 months of therapy.

Three alignment nomograms were constructed on the basis of measurements of the pH dependence on the O2 saturation of the blood. These nomograms, applicable to human blood at 38°C with 10,15 and 20 g%Hb, respectively, present a comprehensive survey of the O2 dependence of the total acid-base status. If PO2, Pco2 and pH as well as the Hb concentration are known, the following data can be obtained without additional calculations or equilibration : actual bicarbonate, total CO2 in the plasma, actual base excess as well as buffer bases and the base excess in fully oxygenated blood, standard bicarbonate and standard pH. The use and the range of application of these acid-base nomograms are discussed.

Diabetes mellitus may be regarded as a syndrome since there are several causes. While hereditary factors are important the influence of the environment is necessary to elicit the clinical state of diabetes in many instances. Studies indicate that diabetes of early onset is mainly hereditary but with advancing age environmental factors become more important. Excessive body weight which has been associated with r esults in a decrease in the effectiveness of insulin. The obese need to produce more insulin to preserve normal glucose tolerance. Those who ha ve a defect in pancreatic beta-cell function are unable to maintain this extra production and become diabetic. Injury to the pancreas sufficient to cause diabetes is not compatible with survival. Head injuries and brain damage are often associated with glycosuria and transient hyperglycemia. Severe general injuries may be followed by hyperglycemia . Severe infections may operate in the same way. Some diuretic drugs may inhibit insulin secretion. Oral contraceptives are mildy diabetogenic because of the estrogen content. With preparations now in use this effect is negligible. Aging increases the proportion of those having abnormal glucose tolerance tests. Secondary diabetes constitutes only about 1% of the number of diabetic persons. Pancreatitis pancreat ic carcinoma and hemochromatosis may damage pancreatic beta-cells. Acromegaly and Cushings syndrome may cause exhaustion of these cells. There is no method of identifying those who are normal but who will eventually be diabetic. However a family history of diabetes high parity birth of a child weighting 10 pounds or more birth of a stillborn child showing hyperplasia of pancreatic islets or the presence of certain skin lesions are suggestive. The characteristic skin lesion known as necrobiosis lipoidica diabetecorum may appear 5-8 years before clinical evidence of diabetes. The oral glucose tolerance test is the usual method of diagnosing diabetes. The glucose-oxidase method may produce false-positive results. jNegative urine tests make diabetes unlikely except in the elderly who may have a high renal threshold. Until recent years the prevalence of diabetes was not suspected. Surveys have shown that the number of new cases discovered have approximated those already known. Every patient seeking advice of a doctor should have the urine tested for glucose especially those with a family history of diabetes high parity women and those over 50 years of age. Geographical variations in prevalence of diabetes are thought to be related to diet. The prevalence in advanced communities is 1-2%. Racial differences have been found. Environmental factors especially diet alter the patterns as standards of living change.

Phosphorylase a activity in the isolated perfused rat heart was about 20 % of the total enzymes. Various standard freezing and thawing procedures or seasonal variation did not alter the basal level of the enzyme activity and is not considered to be the effect of anoxia. Blood and noradrenaline were found to increase phosphorylase activity in the heart. Perfusing the heart with low concentrations of glucose increased phosphorylase activity without changes in cardiac function. A linear relationship between noradrenaline-induced changes in phosphorylase activity and contractile force in the rat heart was observed.

By the thermal analysis of reaction velocity, the catalytic decomposition of the hydrogen peroxide solution by blood catalase (red cell suspension and hemolysate) has been studied, especially the effect of the hydrogen peroxide concentration and that of the blood catalase concentration, with the effect of temperatures (20°-40°C.), and the reaction process was discussed from the standpoint of the adsorption theory and thediffusion theory. The results obtained are asfollows.(1) It has beenfound that the reaction proceeds generally in threestages: the initial stage, the steady stage, and the retarded stage. The duration of the initial stage is practically independent of the concentration of hydrogen peroxide and is nearly in inverse proportion to the concentration of the blood catalase. The steady stage, which is the main part of reaction, is of the first order with respect to hydrogen peroxide, and the reaction velocity constant is proportional to the concentration of the red cell suspension and of the hemolysate.pH6.8; in the case of hemolysate caused by distilled water alone, however, it is nearly proportional to the power 1.3 of its concentration.(2) The reaction proceeds according to theequations: dx/dt=k1ae-k1t-Be-kt at its initial and steady stages, and dx/dt=ka-x√t at its retarded stage.(3) The activity of hemolysate, that is, the velocity constantof the first order reaction, k1, decreases with the time, t', in which the hemolysate was left to stand in the definite temperature. The relation between k1, and√t' is represented by thefollowing expression:logk1=e√t'+logk1in which K1 is an activity where t'=0.ΙeΙ increases with rising temperature.ΙeΙ is decreased as the concentration of hemolysate is decreased, and, between the two, the linear relation is found. In the case of red cell suspension, spontaneous deactivation is not found.(4) The apparent activation energy was found to be 7.18 Cal. in the case of red cell suspension, and 13.9 Cal. in the case of hemolysate.