bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amino Acid Concentrations in Portal Venous Plasma during Absorption from the Small Intestine of the Guinea Pig of an Amino Acid Mixture Simulating Casein and a Partial Enzymic Hydrolysate of Casein
Authors: Sleisenger M. H. , Pelling D. , Burston D. , Matthews D. M. 
Published: August 2015

1. The characteristics of absorption of individual amino acids from amino acid mixtures simulating casein and from enzymic hydrolysates of casein containing oligopeptides as well as free amino acids are known to be different. The differences, which are attributable to mucosal uptake of small peptides, involve more rapid absorption from the enzymic hydrolysates of certain amino acids which are relatively slowly absorbed from the amino acid mixtures. This could lead to more effective utilization of amino acids from the enzymic hydrolysates than from the amino acid mixtures.
2. To obtain further information bearing on this hypothesis, we have used a recently developed technique for portal cannulation in the guinea pig to make a preliminary investigation of amino acid concentrations in the portal venous plasma at intervals after the infusion into the duodenum of equivalent amounts of (a) an amino acid mixture simulating casein and (b) a partial enzymic (papain followed by kidney peptidases) hydrolysate of casein, the two preparations being infused in separate experiments.
3. For some amino acids, such as leucine, isoleucine, valine, phenylalanine and lysine, the curves after the enzymic hydrolysate were fairly similar to the corresponding curves after the amino acid mixture, though usually slightly lower. With other amino acids, the curves after the enzymic hydrolysate were very much lower than the corresponding curves after the amino acid mixture. With serine, glutamine, proline and glycine this discrepancy was particularly great.
4. The results cannot yet be fully explained, but their main features are explicable by the hypothesis that the lower amino acid concentrations in portal plasma after the enzymic hydrolysate are the result of entry of amino acids into the portal blood in peptide form, in which they would not be detectable by the analytical technique employed, and possibly also of more rapid clearance of amino acids from the blood during absorption of this preparation.
Plasma Glucose, Non-Esterified Fatty Acids and Amino Acids in Huntington's Chorea
Authors: Phillipson O. T. , Bird E. D. 
Published: August 2015

1. The metabolic responses to an oral glucose tolerance test (100 g) and an intravenous insulin provocation test (0·1 i.u./kg) were studied in nine control subjects and nine patients with Huntington's chorea.
2. Plasma glucose responses to these stimuli were identical in both groups.
3. High fasting concentrations of non-esterified fatty acid (NEFA) were recorded in the choreic patients when compared with control subjects. This difference was maintained under hypoglycaemic conditions. However, during hyperglycaemia the differences in NEFA concentrations between the groups was abolished.
4. Total plasma tryptophan concentrations were equal in the two groups. Free plasma tryptophan, however, was markedly reduced in the choreic group, and this appeared to be a result of a disturbed relationship between free tryptophan and NEFA concentrations. The abnormalities in free tryptophan values were sensitive to plasma glucose concentrations, as hyperglycaemic conditions markedly reduced the differences between the choreic and control group.
5. Patients with Huntington's chorea showed reduced fasting plasma concentrations of leucine, isoleucine and valine.
The Urinary Excretion of Catecholamines and Their Derivatives in Primary Hypertension in Man
Authors: Bing R. F. , Harlow J. , Smith A. J. , Townshend M. M. 
Published: August 2015

1. The 24 h urinary excretion of adrenaline, noradrenaline, normetadrenaline, metadrenaline and vanilloylmandelic acid has been compared in 17 male normotensive subjects and 25 age-matched male hypertensive patients studied under similar in-patient conditions.
2. 24 h urinary metadrenaline was significantly lower in the hypertensive patients. With this exception, no significant differences were found between the two groups when the total 24 h excretion of free catecholamines and their metabolites was analysed.
3. Diurnal variation in free catecholamine excretion was found in both normotensive and hypertensive subjects. There was no corresponding variation in metabolite excretion.
4. No correlation could be established between systolic or diastolic blood pressure and the amounts of the catecholamines or their metabolites in the urine of either group.
5. The results are considered in the light of recent work demonstrating high plasma catecholamine concentrations in hypertension. They lend no support to the concept that excessive circulating catecholamines are responsible for the elevated blood pressure in essential hypertension.
The Binding of Plasma Proteins to Human Placental Cell Membranes
Authors: Balfour A. H. , Jones E. A. 
Published: August 2015

1. To investigate the relative degree to which human IgG and other plasma proteins bind to cell membranes of the full-term human placenta, suspensions of membranes mixed with radio-iodinated proteins were incubated at pH 6·5 and subjected to Sepharose 2B column chromatography. The amount of labelled protein associated with membrane protein in membrane-containing fractions of the eluate was then determined.
2. Binding of IgG and each of the four subclasses of IgG was appreciable. Binding of IgG was markedly reduced if membranes were incubated at pH 8·0 rather than 6·5. Binding of labelled IgG was inhibited by excess of unlabelled IgG but not by excess of unlabelled albumin. Placental membranes bound much more IgG than did erythrocyte membranes.
3. Binding of insulin was relatively greater than that of IgG, whereas binding of IgE, IgM, IgA, albumin, transferrin and polyvinylpyrrolidone was much less than that of IgG and each of its subclasses.
4. The relative binding of IgG and fragments of the IgG molecule was, in decreasing order of magnitude: light chains, IgG, Fc, heavy chains and F(ab′)2.
5. The results are consistent with Brambell's hypothesis for the mechanism of the transmission of passive immunity from mother to young. In particular the data are consistent with the existence of a limited number of IgG specific receptors on the microvillus membrane of the syncytial trophoblast. Such receptors could protect IgG molecules from degradation during their transplacental transport. The submolecular region of the IgG molecule involved in specific membrane binding appears to be common to all four subclasses and to include the Fc region.
Haemodynamic Characteristics of Low-Renin Hypertension
Authors: Schalekamp M. A. D. H. , Birkenhäger W. H. , Zaal G. A. , Kolsters G. 
Published: August 2015

1. Intra-arterial pressure, cardiac output, renal blood flow and glomerular filtration rate were measured in 19 patients with low-renin hypertension and in 30 patients with normal-renin hypertension.
2. Cardiac output and renal blood flow were significantly lower in low-renin hypertension. Total peripheral and renal vascular resistance were markedly higher in this group.
3. Plasma renin concentration correlated inversely with both total peripheral and renal vascular resistance as well as with age. Multiple regression analysis indicated that part of the relationship between renin and haemodynamic variables did not depend on age. Furthermore, plasma renin concentration did not decrease with age in a group of 40 normotensive control subjects of similar age to the hypertensive patients.
4. The results provide further confirmation that renin decreases as hypertension progresses.
Catabolic rate of α1-antitrypsin of Pi type M and Z in man
Authors: Laurell C.-B. , Nosslin B. , Jeppsson J.-O. 
Published: August 2015

1. Human α1-antitrypsin was isolated from three Pi M and two Pi Z subjects without alteration of its microheterogeneity. The purified proteins were labelled with either 125I or 131I by a lactoperoxidase method.
2. The disappearance rate of two types of α1-antitrypsin were studied after simultaneous injection of labelled M-protein and Z-protein into Pi M subjects.
3. The ratio of extra vascular to plasma pools of α1-antitrypsin ranged between 1·2 and 1·6 with no difference between M- and Z-protein. The mean fractional catabolic rates of M-protein and Z-protein were respectively 0·26 and 0·40 per day.
4. The difference in catabolic rate of Z- and of M-protein is too small to explain why the α1-antitrypsin content of the blood in Pi ZZ subjects is only 15% of that normally found in Pi MM subjects. The low α1-antitrypsin in Pi ZZ subjects appears mainly to be due to a low rate of biosynthesis.
Porphyrins in Erythrocytes and Blood Plasma: Preliminary Studies with Qualitative Thin-Layer Chromatography
Authors: With T. K. 
Published: August 2015

1. A simple chromatographic method for the study of porphyrins in erythrocytes and blood plasma, requiring little technician time, is described. The findings in adults and neonates are presented as well as those from severely ill patients.
2. The regular occurrence of uro-, copro- and proto-porphyrin in erythrocytes is demonstrable as well as sporadic occurrence of tri-, penta-, hexa- and hepta-carboxylic porphyrin. The method gives, however, irregular values for protoporphyrin, which seems to occur in a more labile form in some subjects than in others; this is especially the case in erythropoietic protoporphyria.
3. In blood plasma, uroporphyrin occurs regularly, and coproporphyrin less regularly. Protoporphyrin and penta- to hepta-carboxylic porphyrin are found only occasionally.
Bone Necrosis and Urinary Hydroxyproline Excretion in Rabbits
Authors: Weatherley C. R. , Dale G. , McGurk J. , Walder D. N. 
Published: August 2015

1. Aseptic necrosis of bone is a serious chronic complication of deep-sea diving and compressed-air work.
2. The changes to the bone which occur in this condition take time to develop to the stage where they cause the radiographic signs of bone necrosis, and consequently there is a delay of some months between the causal incident and the first diagnosis by radiography.
3. As a possible method for the earlier detection of bone necrosis the 24 h urinary excretion of hydroxyproline was measured over a period before and after experimental production of bone necrosis in rabbits by the intra-arterial injection of glass microspheres.
4. Total hydroxyproline excretion rose significantly within a few days of the injection in those rabbits in which there was later shown to be histological evidence of bone necrosis. This rise occurred long before there was any radiographic change.
5. It is suggested that measurement of urinary hydroxyproline might be used to give an early indication of bone necrosis in man.
Enzyme Activities of Cells of Different Types Isolated from Livers of Normal and Cholestatic Rats
Authors: Wootton A. M. , Neale G. , Moss D. W. 
Published: August 2015

1. The distribution of three membrane-bound enzymes, alkaline phosphatase, 5′-nucleotidase and γ-glutamyl transferase, has been examined in rat liver fractionated into parenchymal cells, a Kupffer cell fraction and a biliary tract fraction by perfusion with collagenase solution.
2. In control rat livers the highest enzyme concentrations were found in Kupffer cell preparations. The fraction enriched with biliary tract cells showed concentrations two- to fourfold those in isolated parenchymal cells.
3. At 24 h after ligation of the bile duct there was a fourfold increase in the alkaline phosphatase activity in parenchymal cells and a 2·5-fold increase of the same enzyme in the biliary tract fraction. The concentration of alkaline phosphatase in Kupffer cells remained unchanged.
4. 5′-Nucleotidase and γ-glutamyl transferase concentrations tended to decrease after bile-duct ligation for 24 h, the most marked changes being found in Kupffer cells.
5. After bile-duct ligation for 7 days the overall activities of hepatic alkaline phosphatase and γ-glutamyl transferase increased fourfold and there was a small rise in 5′-nucleotidase. For alkaline phosphatase and γ-glutamyl transferase the changes were found primarily in parenchymal cells and in the biliary tract fraction. There was a small rise in the activity of 5′-nucleotidase in parenchymal cells and a fall in activity in Kupffer cells.
6. These data show marked differences in the distribution and behaviour of three enzymes which are often used as alternatives in the assessment of patients with liver disease.
Regulation of Cardiac Output during 2,4-Dinitrophenol-Induced Tissue Hypermetabolism in the Dog
Authors: Liang C. , Hood W. B. 
Published: August 2015

1. Cardiac output increased in proportion to oxygen consumption in intact chloralose-anaesthetized dogs after four successive intravenous infusions of 2,4-dinitrophenol (11 μmol/kg; 2 mg/kg).
2. Splenectomy abolished the increase in cardiac output after the first three doses of 2,4-dinitrophenol. β-Adrenoreceptor blockade by practolol, on the other hand, did not prevent the cardiac output rise after the first 2,4-dinitrophenol infusion, but further increases by 2,4-dinitrophenol infusion were abolished. When splenectomy and β-adrenoreceptor blockade were combined, cardiac output did not increase significantly after all four doses of 2,4-dinitrophenol.
3. Cardiac output and mean systemic arterial blood pressure increased when the splenic venous blood collected after 2,4-dinitrophenol infusion was infused intraportally.
4. In a vascularly isolated, but normally innervated, lower half-body cross-perfusion preparation, cardiac output and mean systemic arterial blood pressure increased in the upper half-body when tissue hypermetabolism was produced in the cross-perfused area by 2,4-dinitrophenol. Neither pulmonary artery wedge pressure nor heart rate changed significantly.
5. This circulatory stimulation, after regional 2,4-dinitrophenol infusion, was abolished or was prevented from occurring by splenectomy.
6. It appears that the normal cardiac output response to tissue hypermetabolism requires both an intact spleen and normally functioning β-adrenoreceptors.
Analytical Subcellular Fractionation of Guinea-Pig Myocardium
Authors: Bloomfield F. J. , Wells G. , Welman E. , Peters T. J. 
Published: August 2015

1. Homogenates of guinea-pig left ventricle were fractionated by differential pelleting and by centrifugation on continuous sucrose density gradients.
2. The principal subcellular organelles of myocardium, characterized by their marker enzyme content, were resolved by density gradient centrifugation in a small-volume zonal rotor. The equilibrium densities (p) of the principal organelles are (with marker enzymes in parentheses): sarcolemma, 1·12 (5′-nucleotidase); lysosomes, 1·16 (N-acetyl-β-glucosaminidase); mitochondria, 1·17 (cytochrome oxidase); peroxisomes, 1·18 (catalase); cytosol (lactate dehydrogenase).
3. The subcellular distribution of various adenosine triphosphatase activities and previously unassigned enzymes was determined. Leucyl-β-naphthylamidase and γ-glutamyl transpeptidase showed both cytosol and sarcolemma components. Ca2+-dependent adenosine triphosphatase showed dual localization to the mitochondria and to the sarcolemma.
Independence of Ethacrynic Acid-Induced Renal Hydrogen Ion Excretion of Sodium-Volume Depletion in Man
Authors: Györy A. Z. , Lissner Dianne 
Published: August 2015

1. Neither the mechanism nor the therapeutic implications of the ability of ethacrynic acid to stimulate renal H+ secretion has been fully explored. Acute studies were carried out in six normal volunteer subjects to determine whether or not the stimulation of H+ excretion depended upon sodium chloride or volume depletion.
2. Depletion was either not corrected, or corrected by one of the following: oral water alone or sodium chloride solution (either 153 mmol/l or 513 mmol/l) intravenously to give zero or slightly positive balances of water, sodium chloride or both at all times. Urine was collected at 2 h intervals before and for 8 h after 100 mg of ethacrynic acid. Electrolytes, pH, total acid, osmolality and true creatinine were measured in each urine specimen and in the serum during the control period and 5·5 h after ethacrynic acid.
3. In all 14 experiments in six subjects, urinary pH was reduced to a mean value 4·78 ± se 0·08 within 2–8 h after ethacrynic acid irrespective of replacement therapy, indicating that the sodium chloride and volume depletions produced by ethacrynic acid were not essential to its effect on urinary pH.
4. Urinary pH correlated inversely (r = −0·81) with the logarithm of the difference between rejected chloride and sodium per unit of rejected chloride, suggesting that the discrepancy between anion-cation reabsorption was intimately linked to generation of H+ gradients, possibly by reducing chloride transport.
5. Three of the subjects were given amiloride (20 mg) with ethacrynic acid: both the pH reduction and the chloride/sodium differentials were abolished, probably by reduction of tubular sodium reabsorption. A specific but opposite effect of both agents on tubular H+ transport cannot be excluded.
The Role of Inhibitors and other Factors in the Pathogenesis of Recurrent Calcium-Containing Renal Stones
Authors: Baumann J. M. , Bisaz S. , Felix R. , Fleisch H. , Ganz U. , Russell R. G. G. 
Published: August 2015

1. In order to assess the relative importance of possible pathogenetic factors in the formation of calcium-containing renal stones, a group of 18 patients (12 men, six women) with active, recurrent stone disease were compared with 16 age-matched control subjects (10 men, six women) given an identical diet.
2. Fifteen (83%) of the patients showed at least one, eight (44%) showed two, and one (6%) patient showed three abnormalities that might predispose to stone formation.
3. Increased urinary calcium excretion was the most common abnormality (11 patients, 61%), particularly in the women (83%).
4. A diminished excretion of inhibitors of crystal formation of calcium phosphate was the next most common abnormality, which occurred in eight patients (44%), all of whom were men. It was largely attributable to a diminished excretion of inorganic pyrophosphate (PPi). The PPi/orthophosphate ratios were also lower in the stone-formers. Significant differences in residual inhibitory activity after enzymatic removal of PPi between control subjects and stone-formers could not be found in 24 h urine samples but were present during certain times of the day. Pyrophosphate showed a higher inhibitory activity in urine than in control solutions, this enhancement being absent in stone-formers.
5. Nine (50%) of the patients, but only one of the control subjects, produced crystal aggregates greater than 50 μm in diameter after an oral load of oxalate.
Potentiation of Pressor Effects of Noradrenaline and Potassium Ions in the Rat Mesenteric Arteries by Physiological Concentrations of Angiotensin II: Effects of Prostaglandin E2 and Cortisol
Authors: Kondo K. , Manku M. S. , Horrobin D. F. , Boucher R. , Genest J. 
Published: August 2015

1. In the perfused rat mesenteric vascular bed, the effects of angiotensin II, cortisol and prostaglandin E2 on the vascular responses to noradrenaline or potassium chloride were studied.
2. Angiotensin II in subpressor concentrations potentiated the vasoconstrictor response to noradrenaline and potassium chloride. This effect of angiotensin II was inhibited in the presence of indomethacin and prostaglandin E2.
3. Cortisol in physiological concentrations inhibited the potentiating effect of angiotensin II.
4. Prostaglandin E2 enhanced the vasoconstrictor response to noradrenaline. This effect was not abolished by cortisol.
5. These results suggest that some actions of angiotensin II and cortisol in vivo are mediated by the regulation of prostaglandin synthesis or release.
A Reappraisal of ‘Osmotic’ Evidence for Intact Peptide Absorption
Authors: Fairclough P. D. , Silk D. B. A. , Webb J. P. W. , Clark M. L. , Dawson A. M. 
Published: August 2015

1. The validity of evidence for intact peptide absorption, derived from analysis of the relation of water and total solute absorption, has been tested.
2. Solute and water absorption from saline solutions of the disaccharide maltose have been studied in the normal human jejunum, using a double-lumen perfusion technique with a proximal occlusive balloon. It was expected that maltose would yield very different results from peptides, because maltose is virtually completely hydrolysed before absorption, whereas a proportion at least of some peptides is transported into the intestinal mucosal cells before hydrolysis. This expectation was not confirmed by experiment.
3. The assumption that the absorbate is always isotonic with plasma has been tested by altering the osmolality of glucose/saline solutions perfused in the jejunal lumen. This assumption was not substantiated by experiment, as when the luminal fluid was hypertonic to plasma, so was the absorbate.
4. It is suggested that our findings with peptides and saccharides could be explained by the production of a hypertonic absorbate by hydrolysis of these solutes to their monomer units. We therefore conclude that analyses of the relation of net solute and water absorption cannot be used to predict the form in which peptides enter the mucosal cells.
Influence of Deoxycholic Acid on Biliary Lipids in Man
Authors: Ahlberg J. , Angelin B. , Einarsson K. , Hellström K. , Leijd B. 
Published: August 2015

1. The duodenal bile acid composition was analysed in 24 control subjects and 107 patients with various types of hyperlipoproteinaemia. A highly significant negative correlation was observed between the proportions of deoxycholic acid and cholic acid as well as between deoxycholic acid and chenodeoxycholic acid. Patients with gall-bladder disease had an increased proportion of deoxycholic acid in their bile.
2. Eight control subjects were studied before and during the ingestion of 1·9 mmol (0·75 g) of deoxycholic acid daily. In these subjects a rise in the proportion of deoxycholic acid was also accompanied by a fall in the proportion of both cholic acid and chenodeoxycholic acid in duodenal bile.
3. The biliary lipid composition and cholesterol saturation was determined before and during the administration of 1·9 mmol (0·75 g) of chenodeoxycholic acid (n = 12) or deoxycholic acid (n = 8) daily for 3–4 weeks. The cholesterol saturation was decreased during the chenodeoxycholic acid ingestion whereas no change occurred in bile saturation during deoxycholic acid administration.
4. Ingestion of chenodeoxycholic acid lowered serum triglyceride and deoxycholic acid lowered the serum cholesterol.
The Effect of Human Pregnancy on the Pulmonary Transfer Factor for Carbon Monoxide as Measured by the Single-Breath Method
Authors: Milne J. A. , Mills R. J. , Coutts J. R. T. , Macnaughton M. C. , Moran F. , Pack A. I. 
Published: August 2015

1. The pulmonary transfer factor for carbon monoxide was measured by the single-breath method in 21 pregnant women with no previous history of cardiac or respiratory disease. Measurements were made at monthly intervals throughout pregnancy and once post partum.
2. The transfer factor was higher in the first trimester of pregnancy than in the non-pregnant state. There was a fall in the transfer factor during pregnancy until 26 weeks gestation, after which no further decrease was observed.
3. The changes in transfer factor were not explained by alterations in haemoglobin concentration or alveolar volume.
4. Simultaneous serial estimations of plasma 17β-oestradiol were performed in all the subjects. There was no obvious direct relation between changes in the concentration of this hormone and transfer factor measurements.