bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intracisternal administration of pergolide, a dopamine receptor agonist, triggers the release of an inhibitor of ouabain-sensitive sodium, potassium-dependent adenosine triphosphatase and enhances vascular reactivity in anaesthetized dogs
Authors: Jandhyala B. S. , Lokhandwala M. F. , Kivlighn S. D. , Ansari A. F. , De Feo M. L. 
Published: August 2015

1. The present studies were undertaken to investigate whether intracisternal administration of pergolide, a dopamine-2 receptor agaonist, triggers the release of an inhibitor of ouabain-sensitive sodium, potassium-dependent adenosine triphosphatase into the circulation and whether such an effect is associated with increases in vascular reactivity in pentobarbital anaesthetized dogs. In different groups of animals, Na+-pump activity was estimated in the plantar and dorsal branches of the lateral saphenous veins by using the 86Rb-uptake method; vascular responsiveness to noradrenaline was studied in the denervated perfused hindlimb.
2. Na+-pump activity was significantly depressed in those blood vessels which were collected at 90 min after central administration of pergolide (12.5 μg/kg intracisternally). In perfused hindlimb studies, vascular responses to noradrenaline were significantly enhanced between 60 and 90 min after pergolide. Since the Na+-pump activity was evaluated in the hindlimb veins, and vascular reactivity was studied on the arterial circulation, the data suggest that the changes in both these variables could have been caused by a circulating substance.
3. In separate series of experiments, plasma samples were collected before and after intracisternal administration of pergolide. The Na+-pump activity was significantly inhibited in the segments of lateral saphenous veins which were incubated in the fresh plasma and/or boiled plasma supernatants, indicating that a heat stable pump inhibitor(s) is released into the circulation after pergolide administration.
4. Effects of pergolide demonstrated in the present study are qualitatively similar to those reported to occur after acute blood volume expansion. Hence it is proposed that central dopaminergic mechanisms may play an intermediary role in the release of the Na+-pump inhibitor(s). However, a non-specific action of pergolide cannot be ruled out at the present time.
Evaluation of mannitol, lactulose and 51Cr-labelled ethylenediaminetetra-acetate as markers of intestinal permeability in man
Authors: Elia M. , Behrens R. , Northrop C. , Wraight P. , Neale G. 
Published: August 2015

1. Factors affecting the intestinal uptake and urinary excretion of mannitol, lactulose and 51Cr-labelled ethylenediaminetetra-acetate (51Cr-EDTA), have been investigated in normal subjects and three patients with ileostomy.
2. The distribution volume of markers within the body, the rate of disappearance from plasma and renal clearance were assessed after an intravenous injection of a mixture of mannitol (2 g), [14C]mannitol (10 μCi), lactulose (0.1 g) and 51Cr-EDTA (5 μCi).
3. The urinary recovery of all the intravenously administered markers was close to 100%. Distribution volumes and patterns of excretion were virtually identical. Oxidation of intravenously administered mannitol accounted for only about 1% of the dose.
4. The passage of an orally administered mixture of markers was traced through the intestine and into urine. Transit time through the gastrointestinal tract was measured by the breath hydrogen method and by radionuclide scanning.
5. The passage of markers from mouth to the large bowel was essentially complete by 3.5 h. In some subjects the marker appeared in the large bowel as early as 30–40 min but in others it took three times as long.
6. After an oral dose the urinary excretion of mannitol fell progressively from 2 to 6 h, whereas the excretion of lactulose and 51Cr-EDTA increased slightly. As a consequence the lactulose/mannitol and 51Cr-EDTA/mannitol ratios in urine collected between 0 and 2 h were more than twofold higher than in urine collected between 4 and 6 h (P &lt; 0.001). After 6 h, the urinary excretion of mannitol and lactulose declined rapidly in all subjects, and was similar to the pattern of excretion of 51Cr-EDTA in subjects with an ileostomy. In contrast, in normal subjects, the excretion of 51Cr-EDTA did not decline rapidly but continued for 24–48 h.
7. Differences in the excretion of mannitol, lactulose and 51Cr-EDTA after oral dosing is due to differences in the temporal pattern of absorption of these markers and not to differences in their distribution volume, oxidation or their clearance by the kidney.
8. The data suggest that the uptake of lactulose by the small intestine persists for longer than the uptake of mannitol, and show that 51Cr-EDTA is readily absorbed in the colon. This study indicates factors which must be considered in the design and interpretation of tests of small intestinal permeability.
Evidence for large intestinal control of potassium homoeostasis in uraemic patients undergoing long-term dialysis
Authors: Sandle G. I. , Gaiger E. , Tapster S. , Goodship T. H. J. 
Published: August 2015

1. The role of the large intestine in the maintenance of K+ balance in uraemic patients established on long-term dialysis was studied with a rectal dialysis technique in 14 normal subjects, ten normokalaemic patients undergoing chronic ambulatory peritoneal dialysis (CAPD), and seven patients undergoing haemodialysis. Dietary K+ intakes in the normal subjects, CAPD patients and haemodialysis patients were 80–100 mmol/24 h, 70–80 mmol/24 h and 60–70 mmol/24 h, respectively.
2. At an initial intraluminal K+ concentration of 45 mmol/l, rectal K+ secretion in the CAPD patients (2.4 ± 0.4 μmol h−-1cm−-2) was greater than in normal subjects (1.2 ± 0.2 μmol h−-1 cm−-2, P &lt; 0.02). Under similar conditions, rectal K+ secretion was also greater in the haemodialysis patients than in normal subjects, both pre-dialysis (3.7 ± 0.4 μmol h−-1 cm−-2, P &lt; 0.001) and post-dialysis (2.4 ± 0.5 μmol h−-1 cm−-2, P &lt; 0.05), even though haemodialysis decreased plasma K+ concentration from 5.3 ± 0.1 mmol/l to 3.5 ± 0.2 mmol/l (P &lt; 0.001).
3. There were no significant differences in rectal Na+ absorption, rectal potential difference, plasma aldosterone concentration, or total body K+ content (measured by whole-body counting of 40K), between the normal subjects and either the CAPD or the haemodialysis patients.
4. These results indicate that K+ homoeostasis is maintained in uraemic patients undergoing long-term dialysis by a combination of K+ losses during dialysis, and enhanced large intestinal K+ excretion. The role of the large intestine appears to be particularly important at higher dietary K+ intakes, and the K+ secretory process is sensitive to changes in plasma K+ concentration.
Decreased systemic formation of prostaglandin E and prostacyclin, and unchanged thromboxane formation, in alcoholics during withdrawal as estimated from metabolites in urine
Authors: Förstermann Ulrich , Feuerstein Thomas J. 
Published: August 2015

1. The rates of secretion into the circulation of prostaglandin E, prostacyclin, and thromboxane A2 were estimated in male alcoholics on the third day of withdrawal and in control subjects by measuring appropriate metabolites in urine.
2. Urinary levels of tetranor-5,11-diketo-7α-hydroxyprostane-1,16-dioic acid (the major urinary metabolite of prostaglandins E1 and E2), of 2,3-dinor-6-ketoprostaglandin F1α (the major urinary metabolite of prostacyclin) and of 6-keto-prostaglandin F1α (the stable hydrolysis product of prostacyclin) were significantly different from the normal subjects in the alcoholic group. In contrast, 2,3-dinor-thromboxane B2 (the major urinary metabolite of thromboxane A2) and thromboxane B2 (the stable hydrolysis product of thromboxane A2) were not significantly different between the groups.
3. These data suggest that the ratio of the vasodilator prostanoids prostaglandin E and prostacyclin and the vasoconstrictor prostanoid thromboxane A2 is lower than in normal subjects, in alcoholics during withdrawal. This may be one causal factor for the higher incidence of hypertension observed in withdrawing alcoholics compared with control subjects.
Adaptation to exercise-induced muscle damage
Authors: Clarkson Priscilla M. , Byrnes William C. , Gillisson Eva , Harper Elizabeth 
Published: August 2015

1. Serum creatine kinase (CK) and muscle soreness, common indicators of muscle damage, were assessed in 16 subjects after performance of two bouts of eccentric exercise spaced 7 days apart. The purpose was (1) to examine rapid muscle adaptation when the ipsilateral limb was exercised on the second bout and (2) to investigate possible central adaptations when the contralateral limb was exercised on the second bout.
2. The LSL group (n = 7) and the LOL group (n = 9) performed the exercise with the ipsilateral and the contralateral limb, respectively. Careful attention was paid to stabilization of the subject so that the contralateral limb was not active in isometric stabilization.
3. For the LSL group, a lower CK and soreness response was found on bout 2 compared with bout 1. For the LOL group, no significant difference in CK response and soreness was found between bout 1 and bout 2.
4. No repeat bout effect was found when the contralateral limb was exercised; therefore central adaptation from performance of the first exercise was minimal. Because a lower repeated bout effect was found after bout 2 using the ipsilateral limb, it was concluded that an experimental design using ipsilateral muscle groups should provide a good model to study rapid muscle adaptation to exercise damage.
Impaired insulin-mediated erythrocyte magnesium accumulation in essential hypertension
Authors: Paolisso Giuseppe , Passariello Nicola , Sgambato Saverio , Torecca Roberto , Buoninconti Raffaello , Varricchio Michele , D'Onofrio Felice 
Published: August 2015

1. This study was designed to investigate variations in erythrocyte magnesium in the presence of insulin (0.1 unit/l) in hypertensive subjects.
2. Plasma and erythrocyte magnesium levels were found to be significantly lower in hypertensive than in normotensive subjects.
3. The impaired response to insulin (0.1 units/l) of erythrocytes from hypertensive patients was not reversed by elevated extracellular Mg2+ (3.6 mmol/l).
4. Erythrocytes of hypertensive subjects showed an increased membrane microviscosity compared with normotensive subjects.
5. Lidocaine decreased erythrocyte membrane microviscosity and increased erythrocyte magnesium levels in the presence of insulin.
Familial pseudohyperkalaemia: Inhibition of erythrocyte K+ efflux at 4°C by quinine
Authors: James David R. , Stansbie David 
Published: August 2015

1. Mechanisms responsible for increased erythrocyte K+ efflux in vitro have been investigated in a patient with familial pseudohyperkalaemia. Mean net K+ efflux (4°C) was 108 nmol h−1 10−9 erythrocytes, seven times greater than the mean for controls (15.2 nmol h−1 10−9 erythrocytes). Net K+ efflux was not increased at 22°C or 37°C and losses at 4°C were reversed by subsequent incubation at 37°C.
2. Erythrocyte glucose consumption (4°C) was 14 nmol h−1 10−9 erythrocytes, similar to the mean for controls of 16.8 nmol h−1 10−9 erythrocytes. This suggests that the increased net K+ efflux (4°C) was not associated with abnormal energy consumption and was therefore unlikely to be due to an abnormality of the Na+, K+-pump.
3. Incubation of erythrocyte suspensions with ouabain (0.1 mmol/l) or frusemide (1 mmol/l) at 4°C or 37°C resulted in no differences in K+ efflux between patient and controls. Incubation with quinine (2 mmol/l), an inhibitor of the erythrocyte Ca2+-dependent K+ channel, reduced net K+ efflux at 4°C, but the effect persisted in Ca2+-depleted erythrocytes, implying that quinine was acting in a non-specific fashion.
4. Chemical pathologists and clinicians must be aware of this condition if inappropriate treatment of pseudohyperkalaemia is to be avoided.
The kidney and cardiovascular system in obstructive jaundice: Functional and metabolic studies in conscious rats
Authors: Heidenreich Stefan , Brinkema Erich , Martin Andreas , Düsing Rainer , Kipnowski Jochen , Kramer Herbert J. 
Published: August 2015

1. The effects of jaundice on renal and circulatory function were investigated in chronic bile duct ligated (CBDL). rats 6 days after surgery. Sham operated (SO) animals served as controls.
2. Body weight was significantly reduced, whereas blood pressure remained unaltered, 6 days after bile duct ligation when serum bilirubin had risen to 169 ± 18 (SEM) as compared with 2.8 ± 0.3 μmol/l in SO rats. When compared with control values before surgery, urinary volume had significantly increased and absolute excretion of sodium, potassium, chloride and phosphate had decreased on day 6 after CBDL. Endogenous creatinine clearance was markedly depressed when compared with SO rats. Whereas fractional excretion of potassium remained unaltered, fractional excretion of sodium and of phosphate was significantly increased.
3. Except for a significant increase in urinary thromboxane B2 (TXB2) excretion in CBDL rats, no significant changes were observed in urinary excretion of prostaglandin (PG) E2, in the synthesis of PGE2, 6-keto-PGF1α and TXB2 by isolated aortic tissue in vitro, nor in renal and cardiac adenosine triphosphatase activities or renal cortical mitochondrial function.
4. The adenosine triphosphate content of kidney cortex and cardiac mitochondrial function were significantly depressed in CBDL rats.
5. The results demonstrate that jaundice in CBDL rats is associated with functional and metabolic disturbances of the kidney and cardiac muscle, which may contribute to the renal and haemodynamic characteristics observed in jaundiced animals and humans.
Metabolic inactivation of vitamin D is enhanced in primary hyperparathyroidism
Authors: Clements M. R. , Davies M. , Fraser D. R. , Lumb G. A. , Mawer E. Barbara , Adams P. H. 
Published: August 2015

1. The elimination half-time of 25-hydroxyvitamin D in plasma was estimated after intravenous injection of the radioactively labelled metabolite in seven patients with primary hyperparathyroidism before and after excision of a parathyroid adenoma.
2. The elimination half-time of 25-hydroxyvitamin D was significantly shortened in primary hyperparathyroidism and reverted towards normal after parathyroidectomy.
3. The increased metabolic clearance of 25-hydroxyvitamin D in primary hyperparathyroidism was accounted for by an increased excretion of vitamin D-derived inactivation products in the faeces.
4. Enhanced hepatic inactivation of 25-hydroxyvitamin D may be important in the development of vitamin D deficiency in primary hyperparathyroidism.
An increase in cerebral benzodiazepine receptors induced by a subacute administration of ammonia, mercaptans and short-chain fatty acids in rats
Authors: Baraldi M. , Zeneroli M. L. , Ventura E. , Vezzelli C. 
Published: August 2015

1. In the search to identify peripheral toxins which could be responsible for the supersensitivity of brain benzodiazepine receptors in experimental models of hepatic encephalopathy, [3H]diazepam-binding studies have been performed on brain tissues of normal rats treated with ammonium chloride, dimethyldisulphide and octanoic acid administered alone or in combination.
2. The subacute administration of the three toxins in combination induced a 30% increase in the number of benzodiazepine recognition sites. The administration of these toxins alone or in combination showed that this increase was mainly linked to the synergistic action of dimethyldisulphide or octanoic acid with ammonia, since dimethyldisulphide plus octanoic acid was ineffective.
3. These observations seem to reinforce the suggestion that these three toxins are able to induce neurochemical derangements similar to those described in experimental hepatic encephalopathy.
Relationship between glomerular filtration rate and renal blood flow at different levels of protein-induced hyperfiltration in man
Authors: Rodríguez-Iturbe Bernardo , Herrera Josē , García Rafael 
Published: August 2015

1. We studied the relationship between changes in glomerular filtration rate (GFR) determined as inulin clearance (CIn), and changes in renal blood flow (RBF), determined as p-aminohippurate clearance (CPAH), after the ingestion of a large (1.35±sem 0.04 g/kg, n = 9), moderate (1.08±0.03 g/kg, n = 10) or mild (0.55±0.02 g/kg, n = 8) protein load given as a meat meal. Control subjects (n = 10) received a carbohydrate meal.
2. CIn and CPAH increased after a protein meal. Two hours after eating the test meal, GFR levels were (mean ± sem) 160.0±13.8 (P &lt; 0.05), 141 ± 7.69 and 127.8 ±9.07 ml/min in the groups that received a large, moderate and mild protein load, respectively. Peak CIn values after the meal were 211.6 ±sem 14.92 (P &lt; 0.001), 177.5±10.88(P &lt; 0.01)and 129.0±8.72 ml/min after a large, moderate and mild protein load, respectively.
3. At peak GFR levels after the meal, filtration fraction (FF) (CIn × 100/CPAH) increased significantly (P &lt; 0.02) with the large and with the moderate protein load, but not with the mild protein load.
4. There was a significant (P &lt; 0.001) positive relationship between increments of FF and increments of CIn, but not CPAH, whether the values were expressed as post-meal/pre-meal ratios or as absolute changes.
5. We conclude that hyperfiltration induced by a large protein load is associated with increments in GFR which are proportionally larger than the increments in RBF and, therefore, cannot be explained by simple vasodilatation. Factors capable of increasing FF operate in the physiological response to a protein meal.
Is alveolar carbon monoxide an unreliable index of carboxyhaemoglobin changes during smoking in man?
Authors: Guyatt Andrew R. , Kirkham Andrew J. T. , Mariner Derek C. , Cumming Gordon 
Published: August 2015

1. We measured alveolar carbon monoxide (CO) after a 20 s breath-holding period and carboxyhaemoglobin both before and after smoking a cigarette on 500 occasions (101 individuals). The two measurements were closely correlated but there was a marked difference in the change or ‘boost’ after smoking one cigarette. The mean relative boosts ([post value—pre value]/[pre + post]/2) for alveolar CO and carboxyhaemoglobin were 7.7% and 20.3%, while negative boosts (fall rather than the expected rise) were seen in 103 of 500 and three of 500 occasions respectively. In 140 studies a third alveolar CO reading taken 5 min later was slightly larger, but the difference was insignificant.
2. In seven subjects where the carboxyhaemoglobin level was raised by breathing a 2% CO gas mixture, the alveolar CO and carboxyhaemglobin boosts were similar (71.7% and 75.2% respectively), and they fell sharply subsequently rather than increasing further as occurred after smoking.
3. We conclude that alveolar CO measurements give a useful estimate of carboxyhaemoglobin level if the subject has not smoked for at least half an hour but that measurements of alveolar CO boost are useless since the act of smoking interferes with alveolar sampling. We postulate that cigarette smoking induces a transient change in pulmonary gas exchange.
Genetic co-segregation of renal haemodynamics and blood pressure in the spontaneously hypertensive rat
Authors: Harrap S. B. , Doyle A. E. 
Published: August 2015

1. To determine the relevance of renal circulatory abnormalities found in the immature spontaneously hypertensive rat (SHR) to the genetic hypertensive process, glomerular filtration rate and renal blood flow were measured in conscious F2 rats, derived from crossbreeding SHR and normotensive Wistar–Kyoto rats (WKY), at 4, 11 and 16 weeks of age by determining the renal clearances of 51Cr-ethylenediaminetetra-acetate and 125I-hippuran respectively. Plasma renin activity was measured at 11 and 16 weeks of age.
2. Mean arterial pressure, glomerular filtration rate and renal blood flow increased between 4 and 11 weeks of age. Between 11 and 16 weeks the mean glomerular filtration rate and renal blood flow did not alter, although the mean arterial pressure rose significantly. At 11 weeks of age, during the developmental phase of hypertension, a significant negative correlation between mean arterial pressure and both glomerular filtration rate and renal blood flow was noted. However, by 16 weeks when the manifestations of genetic hypertension were more fully expressed, no correlation between mean arterial pressure and renal blood flow or glomerular filtration rate was observed. Plasma renin activity was negatively correlated with both glomerular filtration rate and renal blood flow, but the relationship was stronger at 11 than at 16 weeks of age.
3. These results suggest that the reduction in renal blood flow and glomerular filtration rate, found in immature SHR, is genetically linked to the hypertension and may be of primary pathogenetic importance. It is proposed that the increased renal vascular resistance in these young animals stimulates the rise of systemic arterial pressure which returns renal blood flow and glomerular filtration rate to normal.
Degradation by bacterial enzymes of colonic mucus from normal subjects and patients with inflammatory bowel disease: The role of sialic acid metabolism and the detection of a novel O-acetylsialic acid esterase
Authors: Corfield Anthony P. , Williams Andrew J. K. , Clamp John R. , Wagner Susan A. , Mountford Richard A. 
Published: August 2015

1. The activities of enzymes degrading human colonic mucin were examined in faecal specimens from healthy subjects and patients with inflammatory bowel disease.
2. The activity of sialidase was measured using a new physiological substrate related to mucus glycoproteins. In addition, acylneuraminate pyruvate-lyase (N-acetylneuraminate lyase; EC 4.1.3.3.) and a novel O-acetylsialic acid esterase (sialate O-acetylesterase; EC 3.1.1.35) were detected.
3. The O-acetylsialic acid esterase activity was readily detectable in partially purified fractions after Sephadex G-100 chromatography.
4. Patients with inflammatory bowel disease showed significant increases in acylneuraminate pyruvate-lyase and proteinase activity but sialidase activity did not differ from normal. The activity of these enzymes in neutrophils could not account for the differences observed.
Unaltered dopaminergic modulation of aldosterone secretion in cirrhosis
Authors: Bernardi M. , De Palma Rossana , Trevisani F. , Malatesta R. , Baraldini M. , Cursaro Carmela , Gasbarrini G. 
Published: August 2015

1. The responses of plasma aldosterone and plasma prolactin concentrations to metoclopramide (10 mg intravenously) were evaluated over 2 h in eight healthy controls and in 23 patients with cirrhosis (10 without and 13 with ascites). Plasma renin activity, glomerular filtration rate and renal sodium excretion were also determined.
2. Metoclopramide did not significantly influence plasma renin activity, whereas both plasma aldosterone and plasma prolactin rose significantly. The incremental areas under the curves did not differ among controls and cirrhotic patients without and with ascites. No significant correlations between plasma prolactin and aldosterone, either under basal conditions or after metoclopramide administration, were found in either controls or patients.
3. Glomerular filtration rate did not change after metoclopramide. Renal sodium excretion in controls and cirrhotic patients without ascites was also unaffected, whereas it decreased significantly in cirrhotic patients with ascites. In the latter, renal sodium excretion was inversely correlated with plasma aldosterone both under basal conditions and after metoclopramide administration.
4. The dopaminergic control of aldosterone secretion does not appear to be significantly altered in cirrhosis. Metoclopramide administration to cirrhotic patients with ascites leads to an increase in plasma aldosterone that may enhance renal sodium retention.