bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein synthesis in human skeletal muscle tissue: influence of insulin and amino acids
Authors: LUNDHOLM KENT , SCHERSTÉN TORE 
Published: March 2008

Abstract. The effects of a mild stimulation of endogenous insulin secretion on the rate of incorporation in vitro of amino acids into human skeletal muscle protein were compared with the effects on this rate of adding insulin and amino acids in vitro. An intravenous infusion of 0.83 mmol glucose per kg body weight increased both plasma glucose and insulin levels significantly. The rate of incorporation of leucine into protein in isolated muscle fibres was significantly higher if the subjects had received the glucose infusion. Both insulin and a high concentration of amino acids in the incubation medium stimulated this rate. Amino acids stimulated the rate more than insulin and insulin did not further stimulate the amino acid‐stimulated rate. On the other hand, the stimulation of the rate of incorporation by amino acids was the same whether the subjects had received saline and were thus in a basal state or whether they had been infused with glucose (which itself stimulated the rate). The rate of incorporation of leucine was correlated with the tissue concentration of RNA but the correlation was weaker when the rate was stimulated by amino acids than under other experimental conditions. Leucine stimulated the rate of incorporation of phenylalanine but phenylalanine did not stimulate the rate of incorporation of leucine.It is concluded that the rate of incorporation rate of amino acids into protein in isolated human skeletal muscle fibres is subjected to hormonal and amino acid control.
The effect of gastrin on basal and aminoacid‐stimulated insulin and glucagon secretion in man
Authors: REHFELD JENS F. , HOLST JENS J. , KÜHL CLAUS 
Published: March 2008

Abstract. The effect of gastrin on basal and aminoacid‐stimulated glucagon and insulin secretion was studied in eleven normal young subjects. The concentrations of glucagon, insulin and gastrin in plasma or serum were measured radioimmunochemically. The results of amino‐acid‐stimulation were compared to those obtained during a protein‐rich meal.Intravenous injection of synthetic human gastrin‐17 in doses from 15.6 ng to 1 μg/kg increased the concentration of glucagon and insulin in peripheral venous blood to a maximum within 5 min. In spite of the enhanced concentrations of insulin induced by gastrin, corresponding concentrations of glucose were either unchanged or increased. Infusion of a mixture of fifteen aminoacids increased the concentrations of glucose, glucagon and insulin. While the increases in glucose and insulin concentrations were similar to those obtained after a protein‐rich meal, the glucagon response was much larger after the infusion. Injection of gastrin‐17 after 30 min of infusion of aminoacids did not potentiate either the glucagon or the insulin response.The results indicate that gastrin, besides stimulating insulin secretion, can also stimulate glucagon secretion in a dose‐dependent manner. The concentrations of gastrin necessary to stimulate glucagon secretion significantly correspond to the concentrations found in diseases with endogenous hypergastrinaemia (achlorhydria and Zollinger‐Ellison syndrome). While gastrin potentiates the glucose‐induced insulin secretion, it does not potentiate neither the aminoacid‐induced insulin nor glucagon secretion.
Increased plasma noradrenaline and serum gastrin in patients with duodenal ulcer
Authors: BRANDSBORG O. , BRANDSBORG M. , LØVGREEN N. A. , CHRISTENSEN N. J. 
Published: March 2008

Abstract. Serum gastrin, serum insulin, plasma noradrenaline, plasma adrenaline, pulse rate and blood pressure were measured repeatedly during 24 h in six patients with duodenal ulcer and in six control subjects.Mean serum gastrin concentration was 3–4 times higher in duodenal ulcer patients than in controls during both the day and at night. Serum insulin was the same in both groups of subjects.Overnight fasting and mean supine plasma noradrenaline as well as mean supine pulse rate were significantly higher in duodenal ulcer patients than in controls. Plasma adrenaline and arterial blood pressure were the same in patients and controls.These results suggest that sympathetic nervous activity is increased in patients with duodenal ulcer. The increased sympathetic nervous activity may mean that duodenal ulcer patients are subject to more stress than normal subjects or may be compensatory to increased vagal nervous activity presumed by some authors to be present in such patients.
The influence of meal frequency on diurnal lipid, glucose and cortisol levels in normal subjects
Authors: TERPSTRA J. , HESSEL L. W. , SEEPERS J. , GENT C. M. VAN 
Published: March 2008

Abstract. Diurnal levels of serum triglyceride, cholesterol, free fatty acids, glucose, and cortisol were measured in four normal persons on a fixed solid 65% carbohydrate diet under steady state conditions in a metabolic unit.Triglyceride levels in all subjects showed similar patterns, which unexpectedly did not bear a simple relation to meal frequency or distribution. With three equivalent meals per day at 09.00, 12.00 and 17.00 hours, ‘fasting’ triglyceride levels increased by about 0.3 g/1 from a minimum value between 03.00 and 05.00 hours in the morning till before breakfast. After breakfast there was a continued rise till about 15.00 hours and then an overall fall in spite of the meal at 17.00 hours. Isocaloric change to eight equivalent meals, consumed between 09.00 and 23.00 hours, resulted in a similar although slightly more even triglyceride, pattern. On eight equivalent meals, spaced evenly over the entire 24 h period, a different pattern was found with lower triglyceride values at daytime than at night.Increase in meal frequency did not result in a lowering of mean diurnal triglyceride levels. The cholesterol pattern followed the triglyceride pattern most clearly in subjects with high triglyceride levels. Glucose showed the expected postprandial increments.Cortisol rhythm did not change on varying meal frequency.
On the relationship between ketonuria and natriuresis during fasting and upon refeeding in obese patients*
Authors: KOLANOWSKI J. , BODSON A. , DESMECHT P. , BEMELMANS S. , STEIN F. , CRABBE J. 
Published: March 2008

Abstract. This study was conducted to assess whether the natriuresis occurring early in a fast, and the renal sodium retention setting in upon carbohydrate or protein refeeding, can be entirely accounted for on the basis of concomitant changes in renal ketone body and ammonia excretion. To this end, the renal excretion of sodium, 3‐hydroxybutyrate (3‐OHB) and ammonium was determined in non‐diabetic obese subjects submitted to total fast according to the following protocols: (1) 6 day fast: considered as control group (n= 11); (2) 8 day fast save for an isolated 100 g oral glucose load on day 4 (n= 12); (3) 8 day fast with, on day 4, the same glucose load followed by a 6 h infusion of glucagon, 1 mg in 500 ml 5% glucose (n= 7); (4) 5 day total fast followed by 3 days of protein refeeding (53 g protein daily; n = 8). All subjects were refed with a mixed 4.2 MJ diet at the end of the studies.During the initial 3 days of fast, natriuresis was proportional to urinary 3‐OHB excretion while urinary ammonium had not yet increased. Glucose administration on day 4 led abruptly to sodium retention, lasting for 2 days, and correlated with the decline in 3‐OHB excretion. The fall in ketonuria resulted from a drop both of plasma 3‐OHB level and of the renal clearance of 3‐OHB. Glucagon prevented this glucose‐induced reduction in urinary Na as well as in 3‐OHB excretion and clearance, through a direct action on the kidney.These results are in keeping with an important role of ketonuria in changes in sodium excretion during fasting and after carbohydrate refeeding. On the other hand, protein refeeding was followed by a decrease in sodium excretion despite persisting elevated ketonuria. Since, in these conditions, blood glucose levels rose, glucose availability to the kidney tissue may represent an alternative factor influencing renal sodium handling in fasting subjects.
Alpha‐adrenergic antilipolytic effect of adrenaline in human fat cells of the thigh: comparison with adrenaline responsiveness of different fat deposits
Authors: LAFONTAN M. , DANG‐TRAN L. , BERLAN M. 
Published: March 2008

Abstract. The present results show that isolated fat cells from the subcutaneous adipose tissue of the lateral part of the thigh exhibit resistance to adrenaline. However, inability of adrenaline to induce lipolysis is not linked to a β‐receptor defect since a β‐adrenoceptor‐stimulating agent (isoproterenol) exerts a clear lipid mobilizing effect. The blocking of α‐adrenoceptors by phentolamine (an α‐adrenoblocking drug) unmasks the strong lipolytic effect of adrenaline. Moreover, our investigation demonstrates the occurrence of an inhibiting effect of adrenaline on theophylline‐induced lipolysis. This inhibitory effect is suppressed by phentolamine and strengthened by propranolol (β‐adrenoblocking drug). Thus it seems that one of the important facts able to explain adrenaline resistance of the adipocytes from the subcutaneous adipose tissue of the thigh could be increased alpha‐adrenergic responsiveness initiated by mixed agonists such as adrenaline or noradrenaline.Moreover, our data demonstrate that the differences in the lipolytic responses to adrenaline between isolated fat cells taken from different sites could be linked to a variable α‐adrenergic‐inhibiting effect rather than a modified β‐adrenergic effect. In conclusion, the balance between the two receptor site activities could be different according to the anatomical localization of the fat deposits, thus explaining the differences in adrenaline responsiveness reported in this paper.
Acute dietary effects on plasma lipids, lipoproteins and lipolytic enzymes in healthy normal males
Authors: SCHLIERF G. , JESSEL S. , OHM J. , HEUCK C. C. , KLOSE G. , OSTER P. , SCHELLENBERG B. , WEIZEL A. 
Published: March 2008

Abstract. Diurnal plasma lipids and lipoproteins were studied in twelve healthy young males on corn oil and palm oil diets, respectively. The major triglyceride fatty acids were determined serially in the lipoprotein classes during the day. Lecithin‐cholesterol acyl transferase, lipoprotein lipase and hepatic triglyceride lipase were also measured.Diurnal changes of triglycerides and cholesterol were confined to lipoproteins of d< 1·006 kg/l. There was a diurnal rise of lecithin‐cholesterol acyl transferase activity with corn oil but not with palm oil. Fasting and postprandial postheparin lipoprotein lipase and hepatic triglyceride lipase were similar but there was a significant correlation of postprandial hepatic lipase with postprandial plasma triglycerides on palm oil.Marked diurnal changes of triglyceride fatty acids were observed not only in ‘very low density lipoprotein’ but also in high‐density lipoprotein amounting to approximately one third of total high density lipoprotein triglyceride fatty acids.
The subcellular localization of peptidase activity in the human jejunum
Authors: NICHOLSON J. A. , PETERS T. J. 
Published: March 2008

Abstract. The subcellular localization of peptidase activity in the normal human jejunum has been investigated. Subcellular organelles were fractionated by density gradient centrifugation. The localization of peptidases was determined by comparing the distributions of peptidase activities with those of organelle ‘marker’ enzymes. The organelles and their markers were: cytosol—lactate dehydrogenase; brush border—neutral α‐glucosidase, γ‐glutamyl transferase and leucyl‐2‐naphthylamidase; plasma membrane—5′‐nucleotidase; lysosomes—N‐acetyl‐β‐glucosaminidase; mitochrondria—malate dehydrogenase; endoplasmic reticulum—alkaline α‐glucosidase; peroxisomes—catalase.Thirteen dipeptides, seven tripeptides, two tetrapeptides, two pentapeptides and a hexapeptide were used as substrates. The distribution of dipeptidyl peptidase IV was also determined.Irrespective of whether the NH2‐terminal or COOH‐terminal amino acid was neutral, basic or acidic, the major or exclusive locus of dipeptidase activity was cytosolic. All of the activity against a dipeptide with the amino acid proline at the NH2‐terminus was in the cytosol.The distribution of tripeptidase activity was quite different. Although the cytosol hydrolysed all tripeptides, as much as 50% of tripeptidase activity was particulate. For both tetrapeptides, one of the pentapeptides and the hexapeptide, the major or exclusive locus of activity was the brush border membrane. Pentaphenylalanine, however, was hydrolysed by both the cytosol and the brush border. Dipeptidyl peptidase IV was localized in the brush border.
Glucose tolerance, plasma insulin and α‐lipoproteins in young male myocardial infarction survivors compared with controls matched on serum cholesterol concentration
Authors: BERGSTRAND R. , WIKLUND O. , HOLM G. , WEDEL H. 
Published: March 2008

Abstract. In order to identify metabolic risk factors other than hypercholesterolaemia, all cases of acute myocardial infarction, diagnosed in males aged under 40 years, were studied over a period of 6 years in Göteborg, Sweden. Twenty out of twenty‐four patients who were alive at the time of the study were compared with forty controls matched for serum cholesterol concentration. A previous report has noted lower apolipoprotein A (apoA) and a higher α‐lipoprotein triglyceride concentration in these young myocardial infarction patients compared with the matched controls.Basal blood glucose, oral glucose tolerance and plasma insulin levels did not differ between the patients and controls, i.e. decreased glucose tolerance and elevated plasma insulin levels were not found to be additional risk factors for myocardial infarction in young males if serum cholesterol concentration was taken into consideration. This finding could be explained by the fact that patients and controls were all high cholesterol individuals and a difference between the patients and the general population is still possible.Low apoA was a risk factor independent of serum cholesterol as well as glucose intolerance and elevated plasma insulin levels.
Metabolic activity of human polymorphonuclear leucocytes: relation to ingestion rate
Authors: TORRES MARTINE , PROST DOMINIQUE DE , HAKIM JACQUES , GOUGEROT MARIE‐ANNE 
Published: March 2008

Abstract. The ingestion rate and oxygen‐dependent metabolic activities of normal human polymorphonuclear leucocytes were measured with heat‐killed Klebsiella as the particle. Since the experimental conditions were similar for each measurement, it was possible to make direct correlations between each oxygen‐dependent reaction and (1) ingestion rate and (2) the other oxygen‐dependent reactions.In the controls, oxygen‐uptake was more reliably correlated (r= 0.960) with ingestion rates than with (in order of reliability) hydrogen peroxide produced (r= 0.860) and iodination (r= 0.858 and 0.813 for 100 and 20 μmol/l iodide respectively). Hydrogen peroxide production (r= 0.988), nitroblue tetrazolium reduction (r= 0.969) and cytochrome c reduction (r= 0.862) were more reliably correlated to oxygen‐uptake than to ingestion rate, and iodination was better related to hydrogen peroxide production (r= 0.90 and 0.819 for 100 and 20 μmol/l iodide respectively) than to ingestion rate.From these findings it was possible to locate primary defects in abnormal polymorphonuclear leucocytes from individual patients with pyogenic infections, idiopathic refractory anaemia or idiopathic oesteomyelofibrosis with splenomegaly, even when several deficiencies existed.
Stimulation by intragastrically administered E2 prostaglandins of human gastric mucus output
Authors: JOHANSSON C. , KOLLBERG B. 
Published: March 2008

Abstract. Prostaglandin E2 and 15(R)15 methyl prostaglandin E2 were instilled intragastrically to study gastric mucus output in healthy male subjects during an infusion of pentagastrin. Mucus was measured by determining total, free, and bound N‐acetyl neuraminic acid (NANA) in gastric recoveries. NANA is a sialic acid located at the end terminals on the carbohydrate chains of mucus glycoprotein. It contributes to viscosity and prevents enzymatic degradation of mucus.The methyl analogue of prostaglandin E2 increased the gastric output of NANA and inhibited gastric acid secretion in a dose‐dependent fashion. NANA produced in response to the analogue was bound to mucus glycoprotein. Prostaglandin E2 increased the output of NANA without affecting the gastric acid secretion. Both prostaglandin E2 and its methyl analogue increased volumes, pH, and NANA content of gastric aspirates withdrawn prior to start of the pentagastrin infusion, indicating a stimulation of the alkaline gastric secretion.The results show that oral E2 prostaglandins have dual effects on gastric secretion, and that their ability to stimulate mucus production is not secondary to gastric acid inhibition. Further studies are needed to examine whether their effect is mainly to increase the incorporation of NANA into mucus glycoproteins, or to stimulate the release and/or production of gastric mucus, and also to quantitate the gastric nonparietal secretion.The stimulatory properties of E2 prostaglandins on gastric mucus and alkaline secretion may be one mechanism by which they protect the gastric mucosa against experimentally induced damage.
The effects of albumin bound fatty acids on the platelet inhibitory function of human endothelial cells
Authors: NORDØY ARNE , SVENSSON BIRGIT , HOAK JOHN C. 
Published: March 2008

Abstract. This study was carried out to evaluate the effects of albumin‐bound fatty acids on the anti‐platelet effects of endothelial cells. Primary cultures of human endothelial cells (ECM), grown in confluent monolayers, were incubated with plasma or growth medium enriched with albumin‐bound fatty acids (FA) for 2–20 h. The effects of ECM on ADP‐induced platelet aggregation (PA) and collagen‐induced PA and prostaglandin synthesis in platelet‐rich plasma were tested.ECM released an inhibitor of platelet reactions which resembled the activity of PGI2 (prostacyclin). The inhibitory activity was increased by preincubation of ECM with arachidonic acid (AA). A moderate decrease of the activity was obtained by incubation with longchain saturated, monoenoic and dienoic unsaturated fatty acids. A pronounced decrease of the inhibitor was obtained by incubation with di‐homo‐γ‐linolenic acid (DHLA).Paired combinations of AA with the other fatty acids in the incubation medium partially restored the inhibitor activity obtained by the separate FA.The stimulation of the inhibitor by AA was dose dependent and high concentrations of AA reduced this activity.The present study indicates that the quantity and quality of the plasma free fatty acids can affect the endothelial cells' ability to act as a non‐thrombogenic surface.
Arterial blood gas tensions in acute severe asthma
Authors: RUDOLF MICHAEL , RIORDAN J. F. , GRANT B. J. B. , MABERLY D. J. , SAUNDERS KENNETH B. 
Published: March 2008

Abstract. We have studied the serial changes in arterial blood gases in fourteen patients with acute severe asthma, all of whom a standard therapeutic regime and had similar measurements made at identical time intervals under standard conditions.Hypoxaemia on admission was a constant finding, and the arterial oxygen tension often took a week or longer to return to a normal level. Treatment with 60% inspired oxygen provided a safe means of relieving hypoxaemia, provided that blood gases were measured before and during oxygen therapy.Most patients had a normal arterial carbon dioxide tension, which indicated the severity of their illness. Acid‐base disturbances, when present, were mild and needed no specific treatment.Age, duration of the acute attack, and severity of airways obstruction were all unrelated to the changes in blood gas tensions, and pulse rate was found to be a poor predictor of hypoxaemia in elderly asthmatics.Serial measurements of the arterial blood gases should be made in all patients with acute severe asthma.
Interaction of laxatives with enzymes of cyclic AM P metabolism from human colonic mucosa
Authors: SIMON BERND , KATHER HORST 
Published: March 2008

Abstract. The mechanism by which laxatives such as dioctyl sodium sulfosuccinate and ricinoleic acid evoke colonic fluid secretion has been suggested to involve mucosal cyclic AMP. Ricinoleic acid and dioctyl sodium sulfosuccinate were tested for their capacity to modulate the key enzymes of cAMP‐metabolism‐ adenylate cyclase and cAMP‐phosphodiesterase‐in human colonic mucosa.Both laxatives were ineffective stimuli of human colonic adenylate cyclase. In contrast to ricinoleic acid, dioctyl sodium sulfosuccinate was a competitive inhibitor of soluble cAMP‐phosphodiesterase activity. These experiments suggest that the cathartic properties of dioctyl sodium sulfosuccinate in human colonic mucosa might be mediated by cyclic AMP via inhibition of soluble phosphodiesterase activity.
Effects of pancreatic polypeptide on motilin and circulating metabolites in man
Authors: ADRIAN T. E. , GREENBERG G. R. , BARNES A. J. , CHRISTOFIDES N. D. , ALBERTI K. G. M. M. , BLOOM S. R. 
Published: March 2008

Abstract. Pancreatic polypeptide was infused intravenously in healthy fasting subjects at 1 pmol kg‐1 (n= 7) and 4 pmol kg‐1 min‐1 (N= 10) producing plasma PP concentrations of 223±37 pmol/1 (mean ± SEM) and 891±64 pmol/1 respectively. These levels are similar to and four‐fold higher than those seen after a normal mixed breakfast in healthy young adults. In a separate study five healthy subjects ingested a small breakfast during infusion of PP on different days at 1 pmol kg‐1 min‐1 and 2 pmol kg‐1 min‐1 respectively. PP at 1 pmol kg‐1 min‐1 caused a marked reduction in fasting plasma motilin concentrations to 20% of the basal level (P < 0–001). There were, however, no significant changes in plasma concentrations of insulin, glucagon, gastrin, secretin, enteroglucagon, gastric inhibitory peptide or neurotensin.Despite previous reports possibly implicating PP in metabolism, there were no significant effects on blood levels of glucose, alanine lactate, 3‐hydroxybutyrate, glycerol or non‐esterified fatty acids, either in the fasting state or after the ingestion of food. Although it seems unlikely that PP is a major hormonal regulator of intermediary metabolism in man, its ability to suppress motilin at physiological concentrations suggests the possibility of an indirect influence on digestive motor function.
Turnover in humans of β2‐microglobulin: the constant chain of HLA‐antigens
Authors: KARLSSON F. ANDERS , GROTH TORGNY , SEGE KARIN , WIBELL LARS , PETERSON PER A. 
Published: March 2008

Abstract. The turnover of β2‐microglobulin, the common subunit of the HLA antigens, has been examined in normal subjects and in some patients with kidney disorders, multiple myeloma and rheumatoid arthritis. All patients displayed elevated serum levels of β2‐microglobulin. The plasma disappearance curve of 125I‐β2‐microglobulin demonstrated that the protein has a rapid turnover (11/2 = 21 h; range 1 1–2‐8 h) in normal persons and in patients with a normal glomerular filtration rate. In patients with kidney disorders the impaired renal filtration prolonged the turnover time and led to elevated serum levels of β2‐microglobulin.Simultaneous measurements of 125‐β2‐microglobulin in serum and urine allowed estimations of the β2‐microglobulin net reabsorption in the renal tubuli. Two patients with renal disease reabsorbed 84% and 89%, respectively, of the β2‐microglobulin filtered in the glomeruli. In normal persons the net reabsorption is close to 100%.In patients with normal kidney function increased serum levels of β2‐microglobulin seem to be due to an increased synthetic rate of the protein as the elimination rate is normal. HLA antigen heavy chains in serum are present in smaller amounts than β2‐microglobulin. The present data, therefore, suggest an imba‐lanced synthesis of the two chains.