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Biomedical subjects

M C Foss

Publications and source records attributed to M C Foss.

70 records · Page 4Linked to original sources
PubMed1983

Evidence for restoration of hepatic glucose processing in type I diabetes mellitus.

The role of muscle in the processing of dietary carbohydrate in nine type I diabetic patients was assessed using combined forearm-indirect calorimetry-glucose meal (100 g) studies performed before and after 72 h of artificial beta-cell directed insulin therapy. On conventional insulin therapy, initially elevated arterial glucose concentrations rose markedly, free insulin increased slightly, and the respiratory quotient (R.Q.) did not change during the study. The forearm glucose extraction rate increased significantly over basal at 60 min. After 72 h of artificial beta-cell therapy and while still on the instrument, arterial glucose increased moderately, and free insulin levels increased markedly. The R.Q. increased significantly at 60 and 120 min. The forearm glucose extraction rate increased significantly over basal at 30 and 60 min. Importantly, forearm glucose extraction rates did not differ during the two studies at each of the measured time points. These observations demonstrate that conventional insulin therapy is effective in facilitating glucose entry into muscle. In addition, they suggest that the marked improvement in glucose processing exhibited by type I diabetic patients after 72 h of artificial beta-cell therapy is primarily attributable to the liver. Finally, the data strongly imply that the primary clinical objective of insulin therapy in type I diabetes mellitus should be reactivation of the hepatic component of the glucose disposal system.

Adult↗
PubMed1982

Pubertal maturation of the lh stimulatory response to clomiphene citrate in congenital virilizing adrenal hyperplasia.

To determine the LH release response to clomiphene citrate in children with virilizing congenital adrenal hyperplasia (CAH), we examined six patients with glucocorticoid-treated virilizing CAH, five girls and one boy, chonological age (CA) 4 years 2 months-15 years 9 months and bone age (BA) range 8-18 years. All the patients but one, were treated with nocturnal dexamethasone. Their ages at the onset of treatment ranged from 2 years 6 months to 13 years 8 months. An additional boy (CA = 4 years 3 months and BA = 7-8 years) was studied 10 days after removal of a virilizing adrenal adenoma. Clomiphene citrate (3mg/kg/day) was administered orally in two doses/day for 8 days. Venous blood was collected on days 0, 4, 6 and 8. Two patients were also studied in consecutive years. In three patients no increase was noted over the basal levels of LH, but in the others LH rose during clomiphene administration. In two patients studied in consecutive years, there was detectable shift of LH release pattern. The basal LH levels and the sum of responses (day 4, 6 and 8) to clomiphene citrate and particularly their decimal logarithms were statistically significantly correlated with their respective BA. These results confirm that previous prolonged exposure to elevated concentrations of adrenal sex steroids, in children with treated virilizing CAH, may induce precocious maturation of the hypothalamic pubertal mechanism of LH secretion. This maturation was closely correlated with the degree of skeletal maturation.

Adrenal Hyperplasia, Congenital↗
PubMed1982

Restoration of glucose homeostasis in insulin-dependent diabetic subjects. An inducible process.

To assess the change in glucose handling capability of diabetic patients regulated with an artificial beta-cell, five insulin-dependent diabetic subjects were challenged with a 100-g glucose meal while on conventional (*single or split mixed insulin injections) therapy and again after 72 h on an artificial beta-cell unit. It was determined that while receiving conventional therapy, the diabetic patient's capacity to oxidize glucose was severely impaired. In addition, glucose storage was markedly reduced. After 72 h on the artificial beta-cell unit, the diabetic patient's capacity to oxidize glucose following the ingestion of the glucose meal significantly exceeded that of the control group, and glucose storage returned to normal. Since the above study did not reveal the amount of time on the artificial beta-cell required to restore the glucose processing capability of the diabetic patients to normal, their response to a mixed test meal ingested at noon was monitored while they were on conventional insulin therapy and during four consecutive days that they were on the artificial beta-cell. This inquiry revealed a gradual increase in their capacity to oxidize carbohydrate in response to the test meal. In contrast, their ability to store carbohydrate was normalized within 24 h following initiation of artificial beta-cell therapy. These studies clearly reveal that the conventionally treated diabetic patient's capacity to both oxidize and store carbohydrate is severely impaired. Both functions can be restored to normal by the use of the artificial beta-cell for 48-72 h. Most importantly, the gradual improvement in carbohydrate oxidation with respect to the daily mixed meal challenge suggests that it is an "inducible" process which requires at least 2-3 days to accomplish. Since the ability to both oxidize and store incoming carbohydrate is essential for glucose homeostasis, these observations may have significant implications for the care of diabetic patients.

Adolescent↗
PubMed1980

Glucose homeostasis in a carnivorous animal (cat) and in rats fed a high-protein diet.

Glucose homeostasis in a carnivorous (cat) and in an omnivorous (rat) animal fed a high-protein, low-carbohydrate (HP) diet followed a pattern similar to that previously found in carnivorous birds [Am. J. Physiol. 234 (Regulatory Integrative Comp. Physiol. 3): R115-R121, 1978]. Thus, compared to controls given carbohydrate-rich (HC) diets. HP-fed animals had, in the fed state, lower levels of blood sugar, lower concentrations of liver glycogen, and a tendency to reduced body glucose mass. During fasting, their liver glycogen was little mobilized and their glycemia remained remarkably constant. Accordingly, their body glucose mass remained unchanged. Gluconeogenic capacity, already high in the fed state, was not further activated by fasting. Phosphoenolpyruvate carboxykinase activity actually decreased in rat liver cytosol, remaining unchanged in cat liver cytosol and mitochondria. [3H]glucose turnover studies revealed that in HP-fed cats and rats glucose replacement rates in the fed state were as high as in HC-fed animals and that the resistance of their glycemia to fasting depended on the high gluconeogenic capacity and not on a more efficient reduction of glucose utilization.

Animals↗
PubMed1979

The effect of the anticonvulsants phenobarbital and diphenylhydantoin on intestinal absorption of calcium.

The effect of anticonvulsant drugs (phenobarbital and diphenylhydantoin) on the metabolic balance of calcium and on its intestinal absorption, as measured by an in situ intraluminal perfusion method, was studied in rats. The administration of these drugs produced: (a) an increase of the fecal excretion of calcium,. (b) a decrease of the intestinal absorption of calcium (45Ca). Both effects were more intense in rats treated with phenobarbital. There is evidence to suggest that the anticonvulsant drugs affect the intestinal mechanism of active transport of calcium.

Animals↗
PubMedDate not supplied

Hormone-fuel metabolism during exercise of insulin-dependent diabetic patients treated with an artificial B-cell unit.

The effects of restoration of glucose homeostasis on hormone-fuel metabolism of diabetic individuals during exercise (40% maximal O2 consumption) were determined by monitoring fuel oxidation rates and levels of substrates and hormones in nine normal subjects and five insulin-dependent diabetic patients while on conventional insulin therapy and after 3 days on artificial B-cell directed glucose regulation. The non-protein respiratory quotient (npRQ) and carbohydrate oxidation rate of the conventionally-treated diabetic subjects (0.908 +/- 0.002 and 538 +/- 5 mg/m2.min) were lower and the lipid oxidation rate (101 +/- 2 mg/m2.min) was significantly higher than those of the normal group during the bicycle exercise (101 +/- 2 mg/m2.min) was significantly 70 +/- 4 mg/m2.min, respectively). After 3 days of artificial B-cell insulin therapy, the npRQ and carbohydrate oxidation rate of the exercising diabetics significantly increased to 0.965 +/- 0.004 and 693 +/- 13 mg/m2.min, while the lipid oxidation rate declined to 39 +/- 4 mg/m2.min (p less than 0.001). We conclude that artificial B-cell directed insulin therapy increases carbohydrate oxidation and decreases lipid oxidation in exercising insulin-dependent diabetic subjects. However, if restoration of metabolic response identical to that of exercising normals is desired, the excess in carbohydrate oxidation coincident with elevated blood lactate and pyruvate levels suggest that the artificial B-cell therapy may not have been completely optimal, probably due to the hyperinsulinization of the diabetic patients.

Adult↗
PubMedDate not supplied

[Frequency of digestive symptoms in Brazilian patients with Diabetes Mellitus].

PURPOSE: To determine the frequencies of digestive symptoms in an unselected sample of Brazilian diabetics, in comparison to those verified in the general population. METHODS: The frequencies of 13 digestive symptoms were determined in 153 type 1 and type 2 diabetics and in 50 apparently healthy controls, utilizing a structured, standardized questionnaire. RESULTS: The percentage of diabetics with at least one symptom was significantly higher than in controls (70% vs 36%, p = 0.01). Higher frequencies of upper digestive symptoms, such as postprandial epigastric fullness (30% vs 35%), heartburn (30% vs 34%), as well as constipation (17% vs 12%) were observed in both groups. Nevertheless, only the prevalence of dysphagia (13% vs 2%) was significantly increased (p = 0.02) in diabetics. CONCLUSION: These findings indicate that gastrointestinal symptoms are common in diabetics, but this seems also to be the case in the general population, with the exception of dysphagia. The frequencies of symptoms observed in Brazil were similar to those reported in studies from the North Hemisphere, a finding that does not support the hypothesis that external factors may influence the prevalence of gastrointestinal symptoms in diabetics.

Adolescent↗
PubMedDate not supplied

[Study of the frequency of diabetes mellitus and glucose intolerance in patients with cystic fibrosis]

OBJECTIVE: To evaluate the frequency of diabetes mellitus and glucose intolerance in patients with cystic fibrosis treated at the Pediatric Gastroenterology Service of HC-FMRP-USP. METHODS: A cross-sectional analytical study was conducted on a group of 25 patients with mucoviscidosis who were followed up at HC-FMRP-USP. Oral glucose tolerance tests (OGTT) were performed, with simultaneous determination of glycemia and insulinemia. Areas under the curve were obtained for glycemia (G) and insulinemia (I) and the I/G ratio was calculated and correlated with the duration of clinical manifestation and pancreatic exocrine function. RESULTS: Five patients presented alterations: one was diabetic and four had glucose intolerance and/or hyperinsulinemia. There was a direct correlation between the area under the curve for insulinemia and the duration of mucoviscidosis. A significant inverse correlation was also observed between the area under the curve for insulinemia and I/G ratio, and number of enzyme capsules/kg/day. CONCLUSIONS: The frequency of alterations in glucose homeostasis observed in patients with mucoviscidosis was higher than in the population at large (20% of the total sample and 33% of the group of patients with glycemia and insulinemia on OGTT). Therefore, it is important that glucose tolerance tests be performed systematically in patients with mucoviscidosis so that metabolic abnormalities can be early detected, and proper treatment can be initiated.

Journal Article↗
PubMedDate not supplied

Effect of 50 and 100 g glucose loads on peripheral muscle glucose metabolism in normal man.

The present study was designed to determine the effects of 50 and 100 g glucose loads on forearm muscle glucose uptake, oxidation and nonoxidative glucose metabolism in normal man. Ten healthy male subjects were studied during the postabsorptive state (12-14 h overnight fast) and for 3 hours following glucose ingestion. Peripheral glucose metabolism was analysed by the use of the forearm technique to estimate muscle exchange of substrate combined with indirect calorimetry. Greater forearm muscle uptake and nonoxidative metabolism of glucose were observed in the subjects during the G.100 study than during the G.50 study (G.100 = 178.9 +/- 19.7 and 155.3 +/- 23.0 vs 103.5 +/- 16.6 and 85.2 +/- 16.7 mg/100 g forearm muscle. 3 h, respectively). the muscle glucose oxidation did not show significant difference after the two glucose loads. Insulin levels reached after 100 g glucose ingestion were significantly higher than after the 50 g glucose load. In conclusion, this study revealed a dose-dependent metabolic response in the muscular tissue of normal subjects to oral glucose loads of 50 and 100 g, with respect to forearm muscle glucose uptake and nonoxidative glucose metabolism. The oxidative responses of the muscle tissue to the oral glucose challenges seem not to be directly proportional to the ingested meals.

Adult↗
PubMedDate not supplied

Sex-related differences in peripheral glucose metabolism in normal subjects.

The metabolic response of muscle tissue to glucose ingestion was studied in 10 normal men (M) and women (F) by using the forearm balance technique and indirect calorimetry simultaneously. During the 3 hours after a 75 g--oral glucose load, glucose uptake per unit muscle mass was significantly higher in women than in men, F = 187.3 +/- 26.9 vs M = 116.7 +/- 9.5 mg/100 g forearm muscle (P less than 0.05). A significant difference in muscle glucose fate was also observed since the amount of glucose utilized through a nonoxidative pathway was significantly higher in women, F = 84.5 +/- 2.6% (161.8 +/- 27.3 mg/100 g forearm muscle) vs M = 75.3 +/- 2.2% (87.2 +/- 8.6 mg/100 g forearm muscle) (P less than 0.05), whereas the amount of glucose oxidized in relation to glucose uptake was significantly higher in men, M = 24.7 +/- 2.2% (28.2 +/- 3.2 mg/100 g forearm muscle) vs F = 15.5 +/- 2.6% (27.8 +/- 5.4 mg/100 g forearm muscle) (P less than 0.05). No significant differences in insulin response to glucose ingestion were detected between groups. The women showed greater suppression of serum free fatty acids (FFA) levels in relation to basal levels than men. We conclude that: 1) after ingesting 75 g glucose, normal women showed greater glucose uptake per unit muscle mass than normal men, 2) for 3 hours after the ingestion of 75 g glucose, the predominant tendency toward utilizing glucose by a nonoxidative pathway is more marked in normal women than in normal men, and 3) the higher glucose uptake per unit muscle mass in the female group in the presence of an insulin response not significantly different from that of the male group suggests that muscle insulin sensitivity is greater in normal women.

Adult↗
PubMedDate not supplied

[Type 2 diabetic patients in a population sample from Ribeirão Preto area (São Paulo)].

To characterize the prevalence of long term diabetic complications (macroangiopathy, retinopathy, nephropathy and neuropathy) and their possible relation to the degree of metabolic control and duration of diabetes, we studied a hospital-based brazilian population sample of 546 non-insulin dependent diabetic patients. The group was subjected to a standardized evaluation protocol, including clinical characterization of the patients and their disease, current therapy, degree of metabolic control and presence of diabetic complications. The studied sample is of adult age range (25 to 84 years), with mean duration of diabetes of 8.0 +/- 6.8 years. Obesity was observed in 72.6% of the group and 232 patients (43.3%) had diabetics among their relatives. 92 (18.4%) patients have been treated with diet only, whereas 170 (32.6%) also used oral hypoglycemic agents, and 226 (43.7%) were using NPH insulin therapy (81.4% with single daily dose). The mean annual levels of fasting blood glucose (187 +/- 68mg/dl), urine glucose (9.6 +/- 16.7g/day) and glycosylated hemoglobin (12.2 +/- 3.3%) of the group, permitted a classification of the patients in: a) good metabolic control (106 pat. = 19.4%); b) regular control (264 pat. = 48.4%) and c) poor metabolic control (176 pat. = 32.2%). The prevalences of microvascular and neuropathic complications was: retinopathy = 29.1%, nephropathy = 11.3% and neuropathy = 50.9%. The observed increase in the prevalence of the complications was progressive according to the duration of the diabetes. In all time intervals of duration of diabetes, neuropathy was the most frequently observed complication. The prevalence of complications was always higher in the poorly controlled group compared to the patients in good metabolic control.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Effect of glucose ingestion on peripheral glucose metabolism in normal man.

This study was designed to determine the forearm exchange of energetic substrates (glucose and free fatty acids) and the carbohydrate and lipid oxidation rates of normal individuals, in the postabsorptive state and after an oral glucose challenge. Seventeen healthy male volunteers were studied after an overnight fast (12-14 h) and during 3 hours after ingestion of 75 g of glucose. The forearm glucose uptake rate reached the maximum at 60 minutes (0.935 +/- 0.098 mg/100 ml of forearm.min), while 114.9 +/- 9.4 and 90.1 +/- 8.4 mg/100 ml of forearm were the total and incremental peripheral uptake of glucose in 3 hours of study, respectively. After the ingestion of 75 g of glucose, an increase in the oxidation rate of this hexose was observed, corresponding to an increment in the basal oxidation of 21.0 +/- 2.6 mg/100 ml of forearm in 3 hours. The arterial and venous plasma levels of free fatty acids decreased significantly after the glucose meal, associated with a decrease in the lipid oxidation rate. In conclusion, the results of this study showed that, in normal subjects after ingestion of 75 g of glucose, 30.3 +/- 2.1 g (40.4% of the ingested load) of this substrate were processed by the skeletal muscle in the body as a whole and 8.1 +/- 0.6 g were oxidized in this tissue during 3 hours.

Adult↗