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Biomedical subjects

S Walker

Publications and source records attributed to S Walker.

At least 289 records · Page 16Linked to original sources
PubMed1991

A method to assess histamine-induced cyclic AMP production in isolated gastric mucosal cells from human biopsies.

Human gastric mucosal cells were isolated by digestion of fundic biopsies with pronase and collagenase. The mean value of gastric cells per milligram biopsy specimen +/- SEM was 59,000 +/- 4,300 (n = 31) with a viability of 90 +/- 5%. With the cell yield of 1 patient a series of approximately 70-80 cyclic AMP measurements was possible. Histamine stimulated intracellular cyclic AMP production with an EC50 value of 35 +/- 25 mumol/l (SEM; n = 4). In the presence of 100 mumol/l histamine the Ki values (mumol/l) for the histamine H2 receptor antagonists averaged 1.45 (cimetidine), 0.10 (ranitidine), and 0.02 (famotidine). No significant inhibition of histamine-induced cyclic AMP production was obtained with the histamine H1 receptor antagonist triprolidine. With the new method histamine-induced cyclic AMP production can be measured in intact human gastric mucosal cells from fundic biopsy samples.

Biopsy↗
PubMed1991

Effect of omeprazole on nocturnal intragastric pH in cirrhotics with inadequate antisecretory response to ranitidine.

Failure of acid suppression by H2-receptor antagonists has been observed, and recently we have found a higher frequency of patients with inadequate antisecretory response among patients with cirrhosis of the liver. In the present study comprising 16 cirrhotics with inadequate antisecretory response to 300 mg of ranitidine, we tested the effect of 40 mg omeprazole. Nighttime intragastric pH was continuously monitored, and a rise in the intragastric pH above 4.0 for more than 6 h following the oral dose at 18.00 h was considered as response. The median pH profile during the omeprazole treatment was significantly higher than with ranitidine (p less than or equal to 0.001). In contrast to 300 mg ranitidine, which despite sufficient plasma levels 2 and 4 h after intake (762 +/- 431 and 802 +/- 668 ng/ml) resulted in a rise in the nighttime intragastric pH above 4 only for 1.8 +/- 1.7 h, after omeprazole for at least 5 days, the intragastric pH was for 10.1 +/- 2.4 of 12 h above 4 during the night (p less than 0.001). The omeprazole plasma levels were 611 +/- 323 and 881 +/- 533 ng/ml after 2 and 4 h. The data obtained with intragastric pH monitoring indicate that the H+K(+)-ATPase inhibitor omeprazole is able to overcome the H2-blocker resistance in cirrhotics.

Female↗
PubMed1991

Pilot study of anxiety and depression in prepubertal children.

Early detection of anxiety and depression is important because of the relationship between these disorders, suicide and other problems (i.e. social, phobias, learning problems). This study screened prepubertal students in a school setting for symptoms of anxiety and depression using self-report measures (Revised Children's Manifest Anxiety Scale and the Children's Depression Inventory). Controls and children who scored high on measures of anxiety or depression or both were interviewed with their parents and were tested using the Diagnostic Interview for Children and Adolescents (computer version) and the Peabody Individual Achievement Test. Initial results indicated that anxiety is more prevalent in prepubertal children than depression. The correlation between different diagnostic measurements used in this project was calculated. A correlation was found between low scores of self-esteem and high scores of anxiety and depression on self-reports. It is concluded that self-report measures are good screening tools.

Anxiety↗
PubMed1991

Gut lavage fluid proteins as markers of activity of inflammatory bowel disease.

Intestinal secretions may be obtained by gut lavage using a polyethyleneglycol-based electrolyte lavage solution; concentrations of immunoglobulins and other proteins are readily measured in processed gut lavage fluid. As patients with inflammatory bowel disease (IBD) have greatly increased numbers of IgG-producing intestinal immunocytes, we measured gut lavage fluid IgG levels in 44 patients with IBD with various degrees of disease activity to determine whether total IgG in gut lavage fluid reflects disease activity. We also measured levels of albumin in gut lavage fluid, to determine the degree of plasma leakage. Both IgG and albumin levels in the patients with active IBD were significantly higher than those in controls and patients with inactive IBD (all p less than 0.00001). IgG is a more specific index of disease activity than albumin, with no overlap between levels in controls and patients with active IBD. There was a positive correlation (r = 0.68, p less than 0.0001) between IgG and albumin levels, suggesting that gut lavage fluid IgG is mainly plasma-derived.

Adolescent↗
PubMed1991

Addition of misoprostol to ranitidine in non-responders to H2-blockers and pirenzepine.

In the present study, which comprised 14 patients in whom 300 mg and 900 mg of ranitidine as well as in combination with pirenzepine had failed to suppress acid secretion, we tested the effect of adding misoprostol. Night-time intragastric pH was continuously monitored, a rise in the intragastric pH above 4.0 h more than 6 h following the oral dose at 18.00 h being considered a response. In only 1 of the 7 patients with cirrhosis, and in 1 of the 7 control patients, did the combination of 300 mg ranitidine and 400 micrograms of misoprostol result in sufficient acid suppression. Mean pH profiles during the four study periods were not significantly different and the effect of misoprostol was similar in cirrhotics and controls. The inefficacy of the addition of misoprostol in this selected group of patients who did not respond even high doses of ranitidine (+/- pirenzepine) does not favour the hypothesis that gastric mucosal prostaglandin efficiency may be an important factor in the non-response to H2-receptor antagonists. It appears unlikely that the cause is localized solely at the site of H2-receptors.

Alprostadil↗
PubMed1991

A comparison of intrauterine insemination, intraperitoneal insemination, and natural intercourse in superovulated women.

In a prospective comparison of IP, IUI, and natural intercourse following superovulation in couples diagnosed as having unexplained infertility, semen factors, or sperm antibodies, pregnancy rates were found to be significantly higher after IP. Pregnancy rates were also higher in the unexplained infertility group when compared with those with semen factors. It was concluded that IP in combination with superovulation offered a simple, inexpensive, safe alternative to GIFT.

Administration, Intravaginal↗
PubMed1991

Design of Kinemax total knee replacement. Bearing surfaces.

Wear and deformation of the plastic patella component and the tibial bearing surface are recognised concerns in condylar knee designs. This paper discusses an approach to minimising the wear and deformation, while allowing sufficient laxity for activities of everyday living. The femoral component was designed from an average geometry based on sectioning of whole knees. The patella groove of the femoral component has an anatomical profile. The patella component is a close fit in the skyline view, providing a wide area of contact. The laxity requirements were satisfied, based on a 3-D motion study. For the tibial-femoral surfaces, 3-D motion studies showed that plus/minus 12 degrees rotation were needed about neutral, and 13 mm of A-P displacement. A computer program was written to generate the tibial surfaces which allowed for these motions. The contact stresses were considered acceptable for low wear. However, if interchangeability was not required, the stresses could be reduced further. Finally, if the required motion was reduced, especially A-P displacement, stresses could be reduced by over 24 percent. Such a surface was designed for use in heavy, young and active patients.

Biomechanical Phenomena↗
PubMed1991

Laboratory screening of body fluids in self poisoning and drug abuse.

The technical and other requirements of a laboratory service for the screening of drugs in body fluids are presented. The approach to the analyses depends largely upon the nature of the request arriving at the laboratory, the facilities available, and the purpose for which the results are to be used. An acute toxicology drug screen following drug overdose would be treated differently from a batch of samples arriving from a drug dependency unit, and may entail the provision of an on-call or out of hours service. The provision of a drug analysis service should not be undertaken lightly. It depends largely upon the skill and expertise of the analysts, and can be a very costly exercise. It is important to note also that a wrong result can lead to patient mis-management, or ruin the career of an employee, therefore the greatest care must be taken to ensure that results leaving the laboratory are correct.

Body Fluids↗
PubMed1990

Biliary excretion of iron in healthy man and in patients with alcoholic cirrhosis of the liver.

We measured the biliary excretion of iron in 11 patients with alcoholic cirrhosis of the liver and in 10 healthy controls using an intestinal perfusion technique. In the patients with cirrhosis increased amounts of iron in liver tissue were present. The concentrations of iron in the bile samples were determined by atomic absorption spectrometry. The biliary excretion of iron in the healthy controls was 0.32 +/- 0.09 mumol/h and in the patients with cirrhosis it was 0.45 +/- 0.14 mumol/h. The biliary excretion of iron in the patients with cirrhosis was not reduced, indicating that other mechanisms than a reduced biliary excretion of iron must be responsible for the accumulation of iron in liver tissue in alcoholic cirrhosis.

Adult↗
PubMed1990

Gastric emptying in non-responders to H2-receptor antagonists.

H2-receptor antagonists are known to fail to increase the intragastric pH in some patients (so-called non-responders), and we have recently found a higher frequency of non-responders among cirrhotics. Since intragastric pH is also affected by gastric emptying, in the present study we determined the gastric emptying of 300 ml orange juice labelled with [99mTc]-Solco Nanocoll using a gamma camera. Measurements were made over a period of 60 min in cirrhotic patients and controls without liver disease who either responded to 300 mg ranitidine or showed no response. The mean (+/- SD) liquid half-emptying time (T1/2) was 26.3 +/- 17.5 min (range, 9-75 min) in responders (n = 10), 20.9 +/- 8.6 min (range, 7-34 min) in non-responders (n = 10), 19.4 +/- 19.2 min (range, 7-75 min) in cirrhotics (n = 11), and 27 +/- 4.6 min (range, 17-33 min) in controls (n = 9). In 19 of the 20 subjects gastric emptying was normal (T1/2, less than 40 min). Since gastric emptying was not delayed in any of the non-responders, it would appear very unlikely that gastric motility plays a major role in the non-response to H2-receptor antagonists.

Adult↗
PubMed1990

Diffuse esophageal intramural pseudodiverticulosis and nutcracker esophagus in a 54-year-old man.

Esophageal intramural pseudodiverticulosis, which was first described by Mendl et al. in 1960, is characterized by multiple small flask-shaped outpouchings in the esophageal wall. The pseudodiverticula represent dilated excretory ducts of deep mucous glands in the esophagus. The etiology of this rare condition is unknown. Hiatal hernias, gastroesophageal reflux, esophageal strictures, candida esophagitis, herpes esophagitis, diabetes mellitus, and chronic alcoholism have been found associated with intramural pseudodiverticulosis. We report the second case of esophageal hypermotility in intramural pseudodiverticulosis.

Diverticulum, Esophageal↗
PubMed1990

Peripheral blood platelet counts in the management of very early pregnancy failure following gamete intrafallopian transfer.

Early pregnancy-associated thrombocytopenia has been described previously in the peripheral blood of in vitro fertilization (IVF) patients and is evaluated here in 26 women undergoing gamete intrafallopian transfer (GIFT). No consistent fall in platelets was seen in ongoing pregnancies. It is suggested that a fall in peripheral blood platelets in the early luteal phase may be observed only in pregnancies where more than one embryo is present.

Chorionic Gonadotropin↗
PubMed1990

Stability of plasma amiodarone levels during chronic oral therapy.

The variability of plasma amiodarone levels in 51 patients receiving chronic oral therapy over 4-53 (median 19) months was examined; 3-14 (median 5) plasma samples were obtained. After a loading dose, most patients received either 200 mg or 400 mg a day. Mean plasma amiodarone concentration was 1.2 +/- 0.6 mg/l and mean plasma desethylamiodarone concentration was 1.2 +/- 0.5 mg/l. No relationship was seen between height and weight and plasma concentrations. Dose was a significant predictor of plasma level (p less than 0.01) although it was a poor predictor of steady state amiodarone concentration.

Administration, Oral↗
PubMed1990

Biliary excretion of H2-receptor antagonists.

The biliary excretion of ranitidine and famotidine has been studied using percutaneous biliary drainage in patients with complete extrahepatic biliary obstruction due to pancreatic carcinoma. Following 50 mg ranitidine i.v. 0.7 to 2.6% of the dose was recovered in bile collected over 24 h. At steady state (300 mg ranitidine/d po) a similar amount (0.3 to 1.0% of daily dose) was excreted by this route (n = 3). Following single i.v. (20 mg) and oral (40 mg) doses of famotidine (n = 2), even lower percentages (0.1% and 0.4%, respectively) were recovered in the 24 h bile. This negligible biliary excretion cannot account for the so-called second peak phenomenon observed in some individuals following a single dose of an H2-receptor antagonist.

Aged↗