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Biomedical subjects

M Gilbert

Publications and source records attributed to M Gilbert.

At least 217 records · Page 12Linked to original sources
PubMed1983

Primary response to GAT in F344 rats: anti-GAT antibodies, nonspecific immunoglobulins, and expression of the GAT-13 idiotype.

It has been reported that antigen induces differentiation of two populations of Ig-containing cells: the first one to appear, IgCC, synthesizes nonspecific Ig and the second, AbCC, synthesizes antibodies. Along with other arguments, the observation that nonspecific Ig bear idiotypic determinants, which cross-react with those of antibodies, had led to the hypothesis that IgCC are precursors of AbCC. However, the synthesis of such idiotype-positive nonspecific Ig before the appearance of the antibodies has not yet been proven. This problem was investigated by analyzing the primary response to poly(Glu60-Ala30-Tyr10) (GAT) in F344 rats. Kinetics studies of cells synthesizing Ig expressing a major idiotype (GAT-13), and of cells synthesizing Ig not expressing GAT-13 idiotype, revealed that these two cell populations were undetectable before the appearance of the anti-GAT antibodies. This demonstrates that IgCC differentiation is not a necessary condition for the development of all antibody responses.

Animals↗
PubMed1982

Analysis of a major rat idiotype associated with Anti-GAT antibodies.

An anti-idiotypic antiserum was raised in a rabbit against a pool of purified F.344 rat anti-GAT antibodies. GAT-13, the idiotype defined by this serum, is present in all F.344 anti-GAT sera from primary and secondary anti-GAT responses. Anti-GAT sera of 13 inbred rat strains, with different RT1 haplotypes and with different heavy- and light-chain allotypes, all express idiotypic determinants cross-reacting with GAT-13. Thus, like in mice anti-GAT antibodies from rats express public idiotypic determinants. The anti-idiotypic serum also recognizes a highly conserved idiotypic specificity present on mouse and guinea-pig anti-GAT antibodies. The mouse, rat and guinea-pig express a similar highly conserved idiotypic specificity after immunization with GAT. All anti-GAT antibodies from the mouse and guinea-pig bear this idiotypic specificity. These results confirm the existence in the anti-GAT response of interspecies cross-reactive idiotypic determinants.

Animals↗
PubMed1982

Action of salbutamol on carbohydrate metabolism in the rat fetus.

The metabolic action of salbutamol in fetuses was studied after acute (day 21 of pregnancy) and chronic (5 daily infusions from day 16 to day 20 of pregnancy) treatment of pregnant rats. A single injection of salbutamol on day 21 of gestation induced an increase in plasma insulin levels prior to the rise of blood glucose concentration. After the chronic treatment, fetuses from treated mothers showed a decrease in insulin-secreting ability in response to a maternal glucose injection. However, no modifications in fetal liver and placental glycogen contents or in birth weight could be demonstrated. These results suggest that a chronic treatment of pregnant rats with salbutamol could affect the fetal pancreatic responsiveness to glucose.

Albuterol↗
PubMed1982

Glucose turnover rate during pregnancy in the conscious guinea pig.

The glucose turnover rate (GTR) has been determined in conscious pregnant guinea pigs from 33-63 days of gestation. Eighteen animals were studied, using a constant infusion technique of trace amounts of 6-[3H]-glucose and U-[14C]-glucose. The GTR 6-[3H] (mg X min-1) increased progressively with gestation. At term the value is approximately 2-fold higher than in the nonpregnant females. The weight specific GTR 6-[3H] (min X min-1 X kg-1) did not change significantly with gestation. The % of [14C] recycling increased from 0% at 40 days gestation to 20% at term. As with GTR, the metabolic clearance of glucose (ml X min-1) increased with gestational age and exceeded the clearance of nonpregnant animals after 50 days of pregnancy. Expressed per kg of body weight, the metabolic clearance of glucose was not significantly different in pregnant and nonpregnant animals.

Animals↗
PubMed1982

Fetal weight and its relationship to placental blood flow and placental weight in experimental intrauterine growth retardation in the rat.

The effects of experimental intrauterine growth retardation on fetal and placental weight and placental blood flow were studied in rats on day 21.5 of pregnancy. Two experimental approaches were employed. (1) Uterine artery ligation on one side on day 18.5 induced large individual variations in fetal and placental weight as well as in placental blood flow. We showed that fetal weight and placental blood flow were closely related for the values of flow ranging from 0.2 to 1.0 ml.min-1 and the values of fetal weight ranging from 2.5 to 4.5 g. In the opposite horn (control horn), variations of flow ranged from 1.0 to 2.2 ml.min-1 and they occurred without notable change of fetal weight. A relationship between fetal and placental weight was observed as well. In the ligated horn smaller fetuses had smaller placental weight. (2) Maternal fasting, 48 hours before term i.e. between 19 and 21 day of pregnancy decreases both fetal weight and placental blood flow by about 10% and 50% respectively as compared to the control values on day 21. Placental weight is virtually unchanged. The present data allow us to conclude that a marked decrease in maternal placental blood flow might be one of the main causes leading to intrauterine growth retardation.

Animals↗
PubMed1981

Glucose turnover during pregnancy in anaesthetized post-absorptive rats.

During pregnancy the decline in blood [glucose] does not result from the increased distribution space of glucose. The absolute rate of glucose turnover increases in late pregnancy in parallel with the rise in the mass of the conceptus. Nevertheless, glucose turnover per kg body wt. is not increased in late pregnancy, since the lower blood [glucose] decreases glucose utilization by maternal tissues.

Animals↗
PubMed1981

Fetal growth and 1,25-dihydroxyvitamin D3 injections into thyroparathyroidectomized pregnant rats.

Thyroparathyroidectomy (TPTX) in pregnant rats on day 12.5 of gestation was associated with a progressive reduction of dietary intake between days 18 and 21 of gestation. In control mothers with a similar dietary restriction, the fetal plasma calcium and phosphate levels were unchanged, and a slight decrease in fetal weight (approximately 0.8 g) was observed at term. Maternal hypocalcemia in TPTX animals induced chronic fetal hypocalcemia beginning at day 18.5 of gestation; fetal hyperphosphatemia was only statistically significant on the last day of gestation. Weight, blood glucose and liver glycogen stores, which were greatly decreased in fetuses from untreated TPTX mothers, increased after injection of 1,25-(OH)2D3 into TPTX mothers. A marked increase in fetal weight (+ 1.6-2.0 g) occurred at term with doses ranging from 0.05 to 0.25 micrograms/kg of body weight; higher doses (greater than or equal to 0.5 micrograms/kg) inhibited this improvement. Fetal blood glucose was normalized (approximately 45-50 mg/100 ml) when TPTX mothers received 0.05 to 0.5 micrograms/kg, but decreased with higher doses. The highest fetal liver glycogen store (80 mg/g) was achieved using 0.05 micrograms of 1,25-(OH)2D3/kg, this increment being progressively inhibited when larger doses were given. Subcutaneous calcifications were observed in the fetuses of some litters after treatment of the TPTX mothers with 1 microgram of 1,25-(OH)2D3/kg.

Animals↗
PubMed1981

Role of fetal insulin in glycogen metabolism in the liver of the rat fetus.

In the near-term rat fetus liver, insulin decreased phosphorylase a activity, slightly increased synthase a activity and increased both glycogen content and 14C-glucose incorporation into glycogen; anti-insulin serum increased phosphorylase a activity and decreased glucose incorporation but did not modify synthase a activity. When pregnant rats were previously rendered hypoglycemia, insulin injection to the fetus enhanced glycogen accumulation. It is concluded that insulin is a regulatory factor of secondary importance for liver glycogen storage through its action on phosphorylase activity.

Animals↗
PubMed1981

Red blood cell filterability in non-diabetic patients with chronic occlusive arterial disease.

One-hundred and fifty non-diabetic patients with stage II chronic occlusive arterial disease (COAD), were tested for red blood cell filterability (RBF). At the same time, glycaemia, uricaemia, plasma cholesterol and triglycerides, fibrinogen, haematocrit, and white blood cells (granulocytes and lymphocytes) count, mean corpuscular volume, were measured. Thirty healthy people, tested for the same biological parameters, were used as controls. RBF was performed, using the Reid & Dormandy technique, with the same batch of filters (Nuclepore 5 micrometer, No. 54 A8 A25) for patients and controls. Filtration time was expressed in s.ml-1. Values obtained in patients (41.967 +/- 0.889) were significantly different (P less than 0.005) from controls (32.1 +/- 1.329). RBF alteration was correlated (P less than 0.05) with white blood cells count, haematocrit and plasma fibrinogen values. No correlation was observed with other biological parameters.

Adult↗
PubMed1981

[Epilepsy with aggressive behavior. Two cases with depth-electrodes recordings (author's transl)].

Aggressive behavior is popularly thought to be frequently associated with the epileptic character and particularly temporal lobe disorders. However a thorough review of the literature fails to reveal any clear-cut evidence for this belief during inter-ictal periods. Some rare cases of ictal aggressive behavior have been reported but documentation has been difficult because of the previous lack of sophisticated observation equipment and because of difficulties of being present at the time of the seizure. Two rare but definite cases of epileptic aggressive behavior are presented with the help of videotape and E.E.G. recording on the scalp and with depth-electrodes.

Adolescent↗
PubMed1981

Substrate concentration changes during pregnancy in the conscious rat.

Weight gain, food intake and blood metabolite concentrations were investigated in conscious pregnant and non-pregnant rats. A silastic catheter was inserted under light diethyl ether anaesthesia into the carotid artery. Surgery did not significantly affect the weight gain or food intake in pregnant and non-pregnant rats compared with non-operated females. Blood glucose concentration, which was constant during the last half of pregnancy, was 1.4-fold lower than in non-pregnant rats. Blood lactate and pyruvate concentrations were similar in non-pregnant and in pregnant animals until 16.5 days of gestation. Then blood lactate concentration was increased by 50% between 16.5 days of gestation and term, whereas in the same period of pregnancy, blood pyruvate concentration was unchanged. Blood alanine concentration was increased by 150% from 13.5 days of gestation to term. Plasma non-esterified fatty acids concentration increased progressively during the second half of pregnancy to reach values 2-fold higher than in non-pregnant rats. Blood ketone bodies concentrations were unchanged during pregnancy and similar to those observed in non-pregnant animals.

Alanine↗
PubMed1980

Effects of acute variation of fetal glycemia on glycogen storage and on glycogen synthase and phosphorylase activities in the liver of the rat fetus.

The effects of variations of glycemia from 1.7 to 35 mM on the activity of glycogen synthase and phosphorylase, on glycogen content, and on U-14C-glucose incorporation into glycogen in the liver of the near-term rat fetus were investigated. Hypoglycemia did not affect the activities of phosphorylase and synthase; total glycogen content was not modified, but incorporation of labeled glucose was markedly decreased. This is consistent with a decreased glycogen synthesis. A slight hyperglycemia (about 5.5 mM) sharply decreased phosphorylase a (active) activity but increased slightly glycogen synthase a activity; liver glycogen content and labeled glucose incorporation were both enhanced. Higher levels of glycemia induced a decrease of phosphorylase a activity of the same order, but by contrast, glycogen synthase a activity increased progressively with increasing glycemia. Sequential study showed that hyperglycemia first induced the decrease of phosphorylase activity, then increased synthase activity. Marked hyperglycemia strongly enhanced liver glycogen content and labeled glucose incorporation. The fetal liver appears very responsive to acute variations of glycemia. The mechanisms seem to be oriented toward maximal glycogen accumulation.

Animals↗