Misuse of ecstasy.
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3,4-Methylenedioxyamphetamine↗
Biomedical subjects
M L Clark
Publications and source records attributed to M L Clark.
Friendship similarity during early adolescence: gender and racial patterns.
We studied the relationship of reciprocity, gender, and racial composition (Caucasian, African American, cross-race) of adolescent friendship dyads to similarity and proximity in 136 young adolescents. We found that adolescents selected friends who were of the same gender and race and that female dyads were more similar than male dyads on verbal achievement and several personality dimensions. Caucasian dyads were more similar than African American dyads on verbal achievement, mental alertness, and dominance. African American adolescents had more contact with their best friends outside school, whereas Caucasian adolescent friends had more in-school contact. African American students had fewer reciprocal relationships than the Caucasian students. Cross-race friendships were less reciprocal than same-race friendships. Race and gender were important in determining friendship patterns. Similarity and proximity were more important than reciprocity in understanding early adolescent friendships.
Achievement↗
Enhanced sodium absorption by citrate.
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Animals↗
A new model of human secretory diarrhoea using cholera toxin.
Secretory diarrhoea is a major cause of morbidity and mortality worldwide. However, there is no biologically relevant test system in man for assessing new anti-diarrhoeal therapies prior to clinical trial. We have used highly purified cholera toxin in combination with the triple lumen jejunal perfusion technique to establish a subclinical model of cholera in man. Cholera toxin was administered either by mouth with sodium bicarbonate or directly into a 30 cm 'open' or 'closed' (isolated between two inflated balloons) jejunal segment in healthy adult volunteers. Both oral dosing and direct delivery into an 'open' jejunal segment failed to produce consistent secretion of water and electrolytes. In contrast 15 micrograms or 25 micrograms of cholera toxin elicited secretion of water and sodium 3 h after instillation into the balloon occluded 'closed' jejunal segment (P less than 0.05 vs. controls). The rate of secretion was constant over the maximal period studied (4.5 h) and was similar to that reported in human cholera. None of the subjects experienced troublesome diarrhoea. We believe this model offers a relevant test system for assessing anti-diarrhoeal therapy in man.
Administration, Oral↗
Water and solute absorption from hypotonic glucose-electrolyte solutions in human jejunum.
While oral rehydration therapy with glucose-electrolyte solutions is highly effective, the optimal formulation has not yet been defined. Recent clinical studies suggest that stool volume, and thus water losses, may be reduced if glucose is replaced by a polymeric substrate which reduces osmolality. It is possible that the efficacy of glucose monomer based oral rehydration solutions (ORS) will also improve if osmolality is decreased. Using jejunal triple lumen perfusion in healthy adult volunteers net water and solute absorption were studied from three hypotonic solutions with different sodium concentrations (46, 60, 75 mmol/l) but identical glucose concentrations (90 mmol/l), thus allowing osmolality to rise (210, 240, and 270 mOsm/kg, respectively). Results from these solutions (ORS 45:210, ORS 60:240, and ORS 75:270) were compared with the World Health Organisation oral rehydration solution (WHO-ORS). Greatest water absorption was seen with ORS 60:240 (p less than 0.01). Sodium absorption from ORS 60:240 and WHO-ORS was similar and greater than sodium absorption from ORS 45:210 (p less than 0.05). Potassium and glucose absorption were greater from ORS 60:240 than from any of the other hypotonic solutions (p less than 0.05) and were equal to absorption from WHO-ORS). These results in a short segment of healthy human jejunum suggest that hypotonic ORS containing monomeric glucose may increase water absorption.
Adolescent↗
Safety of azathioprine in pregnancy in inflammatory bowel disease.
Although azathioprine has been reported to be safe during pregnancy in renal transplant recipients and patients with systemic lupus erythematosus, opinions vary whether it should be continued in pregnancy in inflammatory bowel disease. A retrospective analysis of the outcome of 16 pregnancies in 14 women receiving azathioprine for inflammatory bowel disease was performed. There was one infective complication of pregnancy (hepatitis B virus infection), but there were no congenital abnormalities or subsequent health problems in the children. This preliminary study suggests that azathioprine is safe in pregnancy in inflammatory bowel disease patients and that termination of pregnancy is not mandatory for those who conceive while taking the drug.
Adult↗
Jejunal water and sodium secretion occurs in chronic idiopathic intestinal pseudo-obstruction.
We observed jejunal water and sodium secretion in two patients with chronic idiopathic intestinal pseudo-obstruction by standard perfusion techniques. The ability of glucose to reverse this secretory state was impaired. These observations suggest that a jejunal secretory state may contribute to the diarrhea in chronic idiopathic intestinal pseudo-obstruction.
Adult↗
Role of cigarette use in hyponatremia in schizophrenic patients.
Urine volume and osmolality were studied in two schizophrenic patients with hyponatremia and six normal subjects after they smoked or ingested cigarettes. The results suggest that cigarette use may contribute to the development of hyponatremia by impairing water excretion.
Adult↗
Background turbidity changes during the estimation of urinary albumin.
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Albuminuria↗
Stability of plasma glucose during storage.
Plasma glucose concentrations were found to decrease during storage. This phenomenon was not method-dependent; it was demonstrated using both a Beckman Glucose Analyser 2 (based on glucose oxidase) and a hexokinase-based technique on a centrifugal analyser. The loss of glucose was typically of the order of 10% in plasma frozen for periods from 24 h to 14 months. Repeated freezing and thawing (weekly for 1 month) did not produce additional loss of glucose compared with aliquots thawed for the first time at 1 month. Fluoride did not reduce the loss of glucose. Glucose was also lost from frozen neutralized perchloric acid extracts of blood (mean +/- SD: 7 +/- 2 per cent over 1 year). We conclude that this variable loss of glucose on storage may complicate the interpretation of metabolic research procedures.
Blood Glucose↗
Evidence that blockade of post-synaptic 5-HT1 receptors elicits feeding in satiated rats.
The effects of nine central 5-HT antagonists on food intake in free feeding male rats were examined. The 5-HT2 antagonists ritanserin and ketanserin and the selective 5-HT3 antagonists ICS 205-930 and MDL 72222 had no effect on food intake. In contrast, the non-selective 5-HT antagonists metergoline, methiothepin, mesulergine, mianserin and methysergide (all of which have high affinity for various 5-HT1 receptor subtypes), dose-dependently increased food intake during a 4-h daytime test. Furthermore, metergoline dose dependently increased food intake over a 24-h period. Surprisingly, mesulergine decreased food intake over a 24-h period at the same doses that increased daytime food intake. This may indicate that the increase in daytime feeding produced by mesulergine is a non-specific response. Although the antagonists used have varying degrees of selectivity for 5-HT receptor subtypes, the pattern of results suggests that postsynaptic 5-HT1 receptors (possibly of the 5-HT1C type) play an important role in the control of feeding in rats.
Animals↗
Relative contribution of ribcage and abdomen during augmented breaths in infants.
Changes in the relative contribution of ribcage and abdomen during augmented breaths were assessed in two groups of infants (less than 2 weeks and 4-12 weeks old). In both groups ribcage and abdominal movements increased during augmented breaths in quiet sleep. In the older infants the relative increase was greater for the ribcage (P less than 0.05) when expressed either as a ribcage to abdominal movement ratio or as a percent of the respective movements during control breaths. In contrast, no significant change of the relative contribution was observed in the younger age group. During active sleep paradoxical movement of the ribcage, observed during tidal breaths, continued during the first phase of the augmented breath; however, during the second phase of inspiration, the ribcage moved outward in all but one infant. Our results show that marked increases in tidal volume are associated with greater increases in ribcage contribution in infants beyond the neonatal period. This may reflect differences in recruitment patterns of intercostal muscles during development.
Abdominal Muscles↗
8-OH-DPAT elicits feeding and not chewing: evidence from liquid diet studies and a diet choice test.
There have been recent claims that the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) elicits chewing and eating of solid but not liquid foods. Therefore, the effects of 8-OH-DPAT and another 5-HT1A agonist gepirone on the consumption of a liquid chow diet, by free feeding male rats, were examined. Both drugs produced a dose-dependent increase in the consumption of liquid diet during a 2 h test. The doses of 8-OH-DPAT and gepirone which increased liquid diet intake in this study were in the same range as those which were found previously to increase food pellet consumption by free feeding rats. The effects of 8-OH-DPAT were also examined in a feeding choice test in which free feeding animals were allowed to choose between food pellets and a liquid chow diet. In this test, 8-OH-DPAT significantly increased total food intake (liquid plus pellet) but had no significant effect on the consumption of either liquid or pellet diets when analysed separately. Thus, there were large individual differences in diet choice after 8-OH-DPAT injection. However, rats did not consistently choose to eat food pellets rather than the liquid diet, as would be predicted if the drug elicited chewing rather than eating. These results provide strong evidence that 8-OH-DPAT elicits a behaviourally specific hyperphagia and not chewing or gnawing.
8-Hydroxy-2-(di-n-propylamino)tetralin↗
Dyadic peer interaction and task orientation in attention-deficit-disordered children.
A sequential observational approach was used to compare peer interactions in 10 mixed dyads of ADD-H and non-Add-H boys and 10 dyads of non-ADD-H boys in laboratory cooperative and school classroom task analogue activities. Mixed dyads were found to have a greater frequency of aggression and less joint activity than control dyads in specific situations. No differences were found for measures of functional attention as measured by frequency, duration, and mean duration of task-oriented behavior. Lag sequential analyses revealed two major sequences that differentiated mixed from normal dyads. These were Verbal Reciprocity (a measure of reciprocal verbal interaction) and Retreat (a measure of social withdrawal following aggression).
Aggression↗
Low gluten diet in the treatment of adult coeliac disease: effect on jejunal morphology and serum anti-gluten antibodies.
Treatment of patients with coeliac disease with a low gluten containing diet (LGD) remains controversial. We have studied jejunal morphology and antigluten (AG) antibody titres by ELISA in patients on a LGD of 2.5-5 g/day for three to 14 months (median six months) and compared results with patients on a strict gluten free diet (GFD) for six to 27 months (median 13 months). We found no significant difference in villous height or crypt depth (eight LGD v 10 GFD patients) or serum AG-IgA, -IgG, and IgM titres (13 LGD v 12 GFD patients). there was however, a significant increase (p less than 0.05) in intra-epithelial lymphocytes in those patients on a LGD. We conclude that adult coeliac patients can tolerate a LGD without gross morphological change and without initiating significant AG antibody responses.
Adolescent↗
Pemphigus vulgaris involving the esophagus. A case report and review of the literature.
A case of pemphigus vulgaris confined to the oral cavity, larynx, and hypopharynx for two years with subsequent involvement of the entire esophagus is presented. Histopathology and direct immunofluorescence of the esophagus confirmed the diagnosis.
Adult↗
Gliadin binding to rat and human enterocytes.
Binding of 125I-crude gluten digest (Frazer's fraction III. FF-III) and 125I-concanavalin A (Con A) to isolated rat enterocytes and of 125I-FF-III to human enterocytes was investigated. Specific binding of 125I-FF-III to rat enterocytes was observed but binding was not inhibited by any of a range of simple and complex saccharides. although casein and bovine serum albumin displaced FF-III at high concentrations. Con A also bound to enterocytes in a specific manner and was inhibited by alpha-methyl-D-mannoside, confirming a lectin-mediated interaction. 125I-FF-III exhibited quantitatively similar specific binding to both normal human and coeliac enterocytes. The primary interaction of gliadin peptides with the enterocyte surface membrane is not lectin-mediated and unlikely to be of fundamental importance in the pathogenesis of coeliac disease.
Animals↗
Is bran efficacious in irritable bowel syndrome? A double blind placebo controlled crossover study.
Twenty eight patients with classical irritable bowel syndrome completed a double blind placebo controlled crossover trial in which they added to their normal diet a daily supplement of either 12 bran biscuits (1 = 1.3 g fibre) or 12 placebo biscuits (1 = 0.23 g fibre). Each biscuit was given for three months in random order with crossover to the alternative biscuit at three months. After the initial three months therapy, there was a significant symptomatic improvement compared with pretreatment in both the bran treated (p less than 0.01) and placebo treated groups (p less than 0.01), but there was no significant difference in symptom scores between these two groups. There was no further improvement in either group after the second three months treatment with the alternative therapy. When crossover data for all 28 subjects were combined, symptoms scores after three months bran therapy and after three months placebo therapy did not differ significantly. Twenty four patients completed three day stool collections in both treatment periods. When the symptomatic response to bran among 15 subjects in whom stool weights rose on bran was compared with that among nine subjects whose stool weights were static or fell on the bran, it was shown that symptomatic improvement was independent of an increase in stool weight. These data suggest that in irritable bowel syndrome, especially that associated with abdominal pain, the beneficial effects of bran are due to a placebo response which is independent of an increase in stool weight.
Adult↗