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Biomedical subjects

M J Saad

Publications and source records attributed to M J Saad.

79 records · Page 5Linked to original sources
PubMed1989

Effect of oral glucose on peripheral muscle fuel metabolism in fasted men.

1. The metabolic adaptations of peripheral muscle during a 5-day "modified" fast (daily oral intake of 200 g of glucose) were studied in 12 normal males. The volunteers were studied initially after receiving a balanced 2,400-kcal diet for at least 3 days (S1) and then after 5 days of modified fast (S2). The forearm muscle exchange of energy substrate (glucose) and the carbohydrate and lipid oxidation rates in muscle were measured during the postabsorptive state (S1) and after an oral glucose challenge (S2). 2. Glucose intolerance was not observed in either situation. Arterial glucose levels increased from a basal value of 83 mg/100 ml to 171 mg/100 ml in S1 and to 187 mg/100 ml in S2 at 30 and 60 min, respectively, and returned to basal values at 180 min in both studies. Increased forearm glucose uptake was observed in S2 compared to S1 (121.7 +/- 17.1 vs 92.6 +/- 12.0 mg 100 ml forearm-1 3 h-1), with decreased glucose oxidation (23.8 +/- 3.7 vs 30.4 +/- 4.7 mg 100 ml forearm-1 3 h-1) and increased glucose storage (98.0 +/- 16.6 vs 62.2 +/- 10.8 mg 100 ml forearm-1 3 h-1) as muscle glycogen. 3. Basal serum free fatty acid (FFA) levels were significantly more elevated in S2 than S1 (1030 +/- 95 vs 657 +/- 59 mumol/l; P less than 0.05) but were markedly reduced by glucose ingestion in both studies (352 +/- 33 (S2) vs 364 +/- 30 (S1) mumol/l at 120 min). Basal FFA oxidation was similar in both studies (0.091 +/- 0.015 (S1) vs 0.105 +/- 0.019 (S2) mg 100 ml forearm-1 min-1) and decreased significantly 3 h after glucose ingestion only in S1 (0.030 +/- 0.010 (S1) vs 0.078 +/- 0.020 (S2) mg 100 ml forearm-1 min-1; P less than 0.05). 4. The insulin response to oral glucose was similar in both studies (11,060 +/- 899 (S1) vs 11,078 +/- 918 (S2) microU ml-1 3 h-1), but the peak concentration occurred later (60 min (S2) vs 30 min (S1] and basal levels were significantly lower in S2 compared to S1 (9.2 +/- 1.7 vs 11.1 +/- 1.5 microU/ml; P less than 0.05). 5. These data show that the metabolic adaptations of normal subjects to a 5-day "modified" fast (daily oral intake of 200 g glucose) were increased muscle uptake of glucose, with reduced glucose oxidation and increased glucose storage in the form of muscle glycogen.

Fasting↗
PubMed1989

Peripheral muscle glucose and potassium transport in a family with acanthosis nigricans and insulin resistance.

This study was designed to determine the forearm exchange of glucose and potassium in four members of a family exhibiting acanthosis nigricans and insulin resistance. Total areas under the curves for potassium release or uptake were within the normal range in all patients. Peripheral glucose uptake, however, was normal in 3 patients and lower in one patient. In the latter patient, the dissociation observed between glucose and potassium transport suggests several manners of differential impairment of insulin action and/or steps distal to the insulin receptor as being responsible for insulin resistance.

Acanthosis Nigricans↗
PubMedDate not supplied

[Study of renal glucose release in rabbits submitted to total functional hepatectomy and norepinephrine infusion].

AIM: To study the possible endogenous sources of glucose in the absence of the liver (equivalent to the anhepatic period of liver transplantation). MATERIAL AND METHODS: A experimental model of total functional hepatectomy in anesthetized rabbits was developed. The aorta and the right renal vein were catheterised in order to collect blood samples to measure glucose contents. The animals were divided into two groups: group 1, 5 animals underwent only norepinephrine infusion; group 2, 15 animals underwent norepinephrine infusion and submitted to total functional hepatectomy. RESULTS: In group 2, before the hepatectomy, arterial glucose levels were higher than venous ones and after the liver removal, the venous levels became higher than the arterial ones. This pattern showed an inversion in the glycemic curves. In group 1 this pattern was not observed. CONCLUSION: The glycemic curves behavior observed in group 2 its not due to norepinephrine infusion, but represents renal glucose release after total functional hepatectomy.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Determination of glucose levels using dried filter paper blood spots: new perspective in home monitoring.

We present a method for the determination of blood glucose using dried filter paper blood spots. To validate this method, we compared our results using filter paper and simultaneously collected venous blood. We demonstrated that there is a linear relationship between the filter paper glucose levels and those determined in whole blood (r = 0.98). There was no significant difference between the results of the two methods (p > 0.05). This method is a cheap alternative which may improve the control of diabetes mellitus, and may also be very useful in the diagnosis of postprandial hypoglycemia and other special situations.

Blood Glucose↗
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

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↗