I . The plasma disappearance of 3H-labelled 25-hydroxyvitamin D, (25(OH)D3) was studied in healthy volunteers on normal and high-fibre diets, using ,H-labelled tracer doses given intravenously.2. The mean ( +SEM) plasma half-life in the high-fibre-diet group was 19.2f 1.7 d, which was significantly shorter than in the group on normal diets (27.5f2.1 d, P < 0.02).3. This finding suggests that a high-fibre diet leads to enhanced elimination of 25(OH)D3 by an action within the intestinal lumen. This may involve interference with an enterohepatic circulation of the metabolite, perhaps by binding of 25(OH)D3 to dietary fibre. We have examined the possibility that a high-fibre diet may increase loss of endogenous 25(OH)D, by measuring the plasma disappearance of radio-labelled 25(OH)D, in healthy volunteers, taking either a normal or a high-fibre diet.
METHODSThirteen healthy Caucasian subjects were studied, twelve male and one female, with a mean age of 32.5 years (range 28-44 years). The project received the approval of the hospital ethical committee and all subjects gave their informed consent.The subjects were allocated to either normal (n 6) or high-fibre (n 7) diets. The high-fibre group took 20 g fine bran (Allinson's Bran Plus) three times daily (equivalent to approximately 20 g dietary fibre/d) in addition to their normal diet, while the only restriction placed on the other group was that they should avoid high-extraction breakfast cereals, wholemeal bread and bran. The diets were started 24 h before the injection of radio-labelled 25(OH)D, and continued for 30 d.
SUMMARY The plasma disappearance of intravenously administered tracer doses of tritiumlabelled 25-hydroxyvitamin D3 (250HD3) was studied in six normal subjects and in 15 patients with intestinal malabsorption. The plasma half-life was significantly shorter and the clearance rate significantly greater in the group with malabsorption compared with the controls. One explanation for this increased elimination could be interruption of an enterohepatic circulation of 250HD occurring in subjects with malabsorption and such a mechanism could account for the loss of endogenous vitamin D in these patients.Vitamin D deficiency and osteomalacia occur in a variety of intestinal disordersl13 and are common after jejunoileal bypass (JIB) for obesity.
Vol. 83 GLUTAMINE METABOLISM IN CARCINOMA CELLS 291oxidation of glutamine results in the formation of aspartic acid. 2. In the presence of substances giving rise to acetyl-coenzyme A, the rate of oxidation of glutamine is decreased, but the extent of oxidation is increased.3. The rate of glutamine oxidation is increased by sodium hydrogen carbonate and a-oxo acids.4. The incorporation of amino acids into proteins is inhibited under anaerobic conditions by pyruvate, oxaloacetate and phenylpyruvate. This inhibition is reversed specifically by glutamine.45. The incorporation of amino acids into proteins is inhibited under aerobic conditions by phenylpyruvate, and this inhibition is reversed by glutamine, pyruvate, oxaloacetate and glucose.6. Glutamine may serve as a source of energy under certain circumstances for the incorporation of amino acids into proteins by these cells.
Perindopril monotherapy is effective and is a viable initial therapeutic option as an antihypertensive agent in African-American individuals with hypertension.
A subgroup analysis of a large US community trial was conducted to evaluate the antihypertensive efficacy and safety of perindopril, an angiotensin-converting enzyme inhibitor (ACEI), in 3159 patients who lacked blood pressure (BP) control at entry with previous antihypertensive therapy. Patients received 4 mg perindopril daily for 6 weeks. Based on physicians' assessment of BP response, the patients were then either maintained on 4 mg daily (group 1) or the dose was increased to 8 mg daily (group 2) for an additional 6 weeks. The mean baseline sitting BP was 158.2/92.9 mm Hg. Perindopril monotherapy produced a significant BP decrease from baseline of 11.6/6.5 mm Hg and 14.9/8.4 mm Hg at weeks 6 and 12, respectively. In group 1 patients, the majority of BP decrease occurred at week 6 (17.3/9.5 mm Hg) and was maintained until the end of week 12 (18.2/10.1 mm Hg). In group 2 patients, the BP decrease on the 4-mg dose was modest at week 6 by 5.2/3.1 mm Hg. However, further dose up-titration of perindopril to 8 mg resulted in a clinically significant BP decrease of 11.9/6.8 mm Hg from baseline to week 12. Significant antihypertensive effects of perindopril were also demonstrated in the special patient populations of elderly (>or=65 years), black, isolated systolic hypertension, patients with concomitant cardiovascular diseases, and patients nonresponsive to other ACEI therapy. Overall, BP control (<140/<90 mm Hg) was achieved in 40.0% of patients at week 12. Perindopril was well tolerated with cough and angioedema reported in 8.5% and 0.4% patients, respectively. Physicians assessed therapeutic response to perindopril as satisfactory in 73.8% patients who were nonresponsive to previous antihypertensive therapy. These results suggest that, in a community-based practice, perindopril monotherapy (4-8 mg/d) is an effective and safe therapeutic option in patients nonresponsive to previous antihypertensive therapy.
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