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Biomedical subjects

K Walker

Publications and source records attributed to K Walker.

At least 127 records · Page 7Linked to original sources
PubMed1989

Effect of oral enprostil, a synthetic prostaglandin E2, on intestinal brush border membrane lipid composition following abdominal irradiation in the rat.

Previous studies have demonstrated that external abdominal irradiation alters intestinal nutrient transport and brush border membrane (BBM) phospholipid content. This study was undertaken to assess the possible protective effect of oral dosing of enprostil, a synthetic E2 prostaglandin, on the BBM marker enzyme and lipid composition of non-irradiated control (CONT) animals and of rats exposed seven days perviously to a single dose of 600 cGy external abdominal irradiation (RAD). Half the CONT and RAD animals were orally dosed with enprostil 5 mcg/kg body weight, two and one mornings before the day of irradiation, and one hour before 600 cGy; the remaining half were dosed with placebo according to the same schedule. BBM were isolated and purified from the animals seven days post-irradiation for analysis of marker enzymes and lipid composition. Radiation was associated with a decline in jejunal and ileal BBM activity of sucrase. Enprostil was associated with a decline in the ratio of alkaline phosphatase/sucrase in jejunal BBM from irradiated rats, despite its preventing a radiation-associated decline in BBM sucrase activity. Radiation was associated with changes in ileal BBM phospholipids, and these alterations were not prevented with enprostil. Furthermore, enprostil given to non-radiated control rats altered BBM composition, such as increased jejunal and ileal lysophosphatidylethanolamine, and lowered ileal BBM sphingomyelin and phosphatidylethanolamine. Thus, enprostil failed to protect the intestine from the effects of abdominal irradiation on BBM phospholipids, but did partially prevent the effect of abdominal irradiation on jejunal sucrase activity.

Abdomen↗
PubMed1988

The value of pre-operative intracavitary radiotherapy in patients treated by radical hysterectomy and pelvic lymphadenectomy for invasive carcinoma of the cervix.

Two hundred and twenty-four patients with invasive carcinoma of the cervix treated by radical surgery have been studied retrospectively to determine the impact of pre-operative intracavitary radiotherapy. Pre-operative radiotherapy made no difference to survival, the incidence of local recurrence, distant metastasis or complications.

Adult↗
PubMed1988

Obstetric practice in St Kitts and the Homerton Hospital, London.

Corinne Hayes and Karen Walker won 1000 pounds in last year's Student Elective Award competition for the protocol of their project. Here, they give an account of their work, the aims of which were to compare the incidence of low birthweight (less than 2.5 kg) and very low birthweight (less than 1.5 kg) babies in the UK and the Caribbean, to assess the outcome of these babies and to compare obstetric practice and the incidence of risk factors for low birthweight in the two populations.

Black People↗
PubMed1988

Use of polyunsaturated fatty acid diet to treat the enhanced intestinal uptake of lipids in streptozotocin diabetic rats.

Intestinal passive transport of lipids is enhanced in rats with streptozotocin-induced diabetes. The present study was undertaken to test the effect of semisynthetic isocaloric diets, varying in saturated (S) or polyunsaturated (P) fatty acid content, on intestinal lipid uptake when fed to rats previously rendered diabetic. In vitro uptake of fatty acids and cholesterol was higher in the jejunum and ileum of diabetic rats than in control rats fed rat chow. Feeding P prevented the enhanced jejunal and ileal uptake of 18:1 and 18:2, and feeding S prevented the enhanced jejunal uptake of 18:2 in diabetic rats fed rat chow. In diabetic rats, feeding P was associated with reduced jejunal uptake of 16:0 and 18:1 and reduced ileal uptake of 16:0, 18:0, and 18:2, as compared with diabetic rats fed S. Weight gain and blood glucose concentration was similar in diabetic animals fed chow, P or S. The percentage of the jejunal wall comprised of mucosa was greater in diabetic than in control rats fed chow or P but was similar in control and diabetic rats fed S. However, this diminution in uptake was not explained by these differences. The potential long-term role of feeding P in the diminution of the hyperlipidemia associated with human diabetes remains to be established.

Animals↗
PubMed1987

Treatment of the enhanced intestinal uptake of glucose in diabetic rats with a polyunsaturated fatty acid diet.

Intestinal absorption of most nutrients is enhanced in diabetic rats. We wished to test the hypothesis that manipulation of dietary fatty acids will modify enhanced uptake of glucose in rats with established streptozotocin-diabetes. Chow-fed control rats or animals with one week of streptozotocin-diabetes were continued on chow or were fed ad libitum for three weeks with semisynthetic isocaloric diets containing a high content of either essential polyunsaturated or non-essential saturated fatty acids. The jejunal and ileal in vitro uptake of varying concentrations of glucose was much higher in diabetic than control rats fed chow or the saturated fatty acid diet. In contrast, the enhanced uptake of this sugar was reduced or normalized in diabetic rats fed the polyunsaturated fatty acid diet. Feeding the polyunsaturated fatty acid diet was associated with increased brush-border membrane activity of alkaline phosphatase in diabetic jejunum and ileum, but neither the saturated fatty acid diet nor the polyunsaturated fatty acid diet altered brush-border membrane cholesterol or phospholipids in control or in diabetic rats. Mucosal surface area was similar in diabetic rats fed the saturated fatty acid diet or the polyunsaturated fatty acid diet. Thus, (1) feeding the polyunsaturated fatty acid diet diminishes the enhanced jejunal and ileal uptake of glucose in diabetic rats, and (2) the influence of the polyunsaturated fatty acid diet on uptake in diabetic rats was not explained by alterations in intestinal morphology or brush-border membrane content of cholesterol or phospholipids. This study suggests that manipulation of dietary lipids may play a role in the normalization of the enhanced intestinal glucose uptake in rats with established diabetes.

Animals↗
PubMed1987

The treatment of metastatic prostatic cancer with the slow release LH-RH analogue Zoladex ICI 118630.

The clinical and endocrine response to a depot preparation of the LH-RH analogue ICI 118630 (Zoladex) was assessed in 55 untreated patients with advanced prostatic cancer. Whereas gonadal androgen suppression was achieved in all patients, subjective and objective clinical response occurred in only 69%, indicated by a relief of bone pain, a decrease in the size of the primary tumour and lymph node metastases and improvement in bone scan appearances. A third of these patients, however, subsequently showed progression of their disease. Serious side effects were not encountered in this study. The depot formulation is a simple, safe and convenient method of administering Zoladex and offers an alternative treatment for metastatic prostatic cancer.

Acid Phosphatase↗
PubMed1987

Diets alter jejunal morphology and brush border membrane composition in streptozotocin-diabetic rats.

Previous studies have demonstrated enhanced active and passive uptake of many nutrients in animals with experimental diabetes. These changes in absorption cannot be explained by differences in intestinal morphology, although the brush border membrane (BBM) phospholipids do change in diabetes. Manipulation of diet produces alterations in intestinal uptake of lipids and glucose. This study was undertaken to determine the effect of diet and diabetes on jejunal morphology and BBM lipid composition. Rats were rendered hyperglycemic with streptozotocin and were fed for 2 weeks on a diet that was high or low in carbohydrate, essential fatty acids, cholesterol, or protein. In both control and diabetic rats, these diets produced changes in villus height and BBM sucrase and alkaline phosphatase activities. In both control and diabetic rats, BBM phospholipids were unaffected by changes in the dietary content of essential fatty acids, cholesterol, or protein, but total BBM phospholipid content was reduced in animals fed low as compared with high carbohydrate diet. Total BBM phospholipid content was higher in diabetic than in control animals fed the low protein diet, whereas BBM phospholipid content was lower in diabetic than in control animals fed the high carbohydrate diet, and was even lower in diabetic animals fed the low as compared with the high carbohydrate diet. These changes in total phospholipids were due to alterations in the BBM content of phospholipids containing choline. In control animals, BBM cholesterol was higher in rats fed the low as compared with the high cholesterol diet, or the low as compared with the high protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

A high linoleic acid diet diminishes enhanced intestinal uptake of sugars in diabetic rats.

Intestinal absorption is altered in rats by diabetes and by dietary manipulation. For 5 wk rats were fed chow (C) or semisynthetic diets containing isocaloric amounts of a high content of either polyunsaturated (P) or saturated (S) fatty acids; then half were rendered hyperglycemic with streptozotocin while the remaining half served as nondiabetic controls. Studies were performed after a total of 8 wk on C, P, or S. Jejunal villous surface area was greater in diabetic rats than in control rats fed C or S, whereas the jejunal mucosal surface area was significantly greater in diabetic animals than in control animals only when they were fed S. Ileal mucosal surface area was similar in diabetic and in control rats fed C, S, or P; although ileal villous surface area was greater in diabetic than in control rats only when they were fed C. The jejunal and ileal uptake of varying concentrations of glucose and galactose was higher in diabetic rats than controls fed C or S. In contrast, the enhanced uptake of these sugars was reduced or normalized in diabetic rats fed P. The jejunal brush-border membrane (BBM) content of phospholipids was higher in diabetic than in control rats fed chow, but there was no difference in diabetic vs. control animals fed P or S in BBM total free fatty acids, phospholipids, or cholesterol. Thus feeding a high linoleic acid diet diminishes the enhanced intestinal uptake of glucose and galactose in diabetic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Vitamin A status in 137 patients with Crohn's disease.

Serum retinol and serum carotene concentrations were determined over a 6-month period in 137 outpatients with Crohn's disease. Serum retinol measurements were within the reference range for all patients at each assessment period, while serum carotene levels were low in about one quarter of the patients. Of the 56 patients who completed 48-hour stool collections, 41% had stool fat values exceeding the reference value. Serum retinol concentrations were not significantly correlated with the serum carotene concentrations, with the 48-hour stool fat content, or with the Crohn's disease activity. In contrast serum retinol concentrations were correlated with the dietary levels of vitamin A. Serum carotene concentrations were inversely correlated with the stool fat content but were not related to Crohn's disease activity or dietary levels of carotene or total vitamin A. Thus: (1) serum retinol concentrations were normal in this moderately large group of patients with Crohn's disease and did not reflect a low dietary vitamin A intake by 34% of the population; (2) serum carotene levels were frequently low in patients with Crohn's disease, possibly due to the presence of steatorrhea, but were not related to low dietary intakes of carotene or to active Crohn's disease, and (3) a low serum level of carotene does not indicate that the patient is at risk of developing vitamin A deficiency.

Adult↗
PubMed1987

Enprostil reduces G-cell hyperplasia and hypergastrinemia in duodenal ulcer.

A 42-year-old man with a 26-year history of duodenal ulcer volunteered for a 24-hour intragastric pH monitoring study, at which time his fasting gastrin concentration was found to be elevated. Secretin injection decreased the serum gastrin concentration. When not on treatment his total gastrin, gastrin-17 (G-17), and gastrin-34 (G-34) response to a protein-containing breakfast was marked. Immunocytochemical staining of antral biopsies showed hyperplasia of gastrin-containing cells, more pronounced for G-17 than for G-34. Cimetidine or cimetidine plus pirenzepine increased 24-hour intragastric pH, whereas pirenzepine alone rendered the gastric contents more acidic, particularly overnight. The total serum gastrin concentrations increased after meals and were unaffected by cimetidine or pirenzepine; enprostil, however, reduced the postprandial increase in total gastrin, G-34, and G-17. After six weeks of treatment with enprostil, the number of cells containing G-17 and G-34 was reduced. The findings show that G-cell hyperplasia may occur in the presence of a normal fasting serum gastrin concentration; fasting serum gastrin concentrations may fluctuate widely over time; the food-stimulated increase in G-17 was greater than that for G-34, and is associated with more pronounced antral hyperplasia for G-17 and G-34; and enprostil blunts the postprandial increase in G-17, G-34, and total gastrin. These observations suggest that enprostil may reduce G-cell hyperplasia and hypergastrinemia.

Adult↗
PubMed1987

Iron, folate, vitamin B-12, zinc, and copper status in outpatients with Crohn's disease: effect of diet counseling.

Iron, folate, and vitamin B-12 status was found to be poor in a substantial proportion of outpatients with generally inactive Crohn's disease. Diet counseling was associated with a normalization of TIBC and serum folate over a 6-month period, but no other consistent benefits were noted despite moderate improvements in intake. The outpatients appeared to be at low risk of developing a zinc or copper deficiency.

Adult↗