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Biomedical subjects

M Gilbert

Publications and source records attributed to M Gilbert.

At least 235 records · Page 13Linked to original sources

Subjective recording of fetal movement.

A group of 137 patients, 113 of whom had obstetric complications, recorded fetal movements by a subjective method. Low fetal movement counts were associated with maternal cigarette smoking and prolongation of pregnancy and high counts with maternal ingestion of sedatives or tranquillizers, abnormal fetal heart rate in labour and a true knot in the umbilical cord. The absence of fetal movement during four consecutive 20-minute counting-sessions was not associated with poor fetal outcome. Further investigations to assess the usefulness of fetal movement counting are recommended. Such investigations should take into account the limitations imposed by the methods and the obstetric population for study.

Birth Weight↗

Glucocorticosteroid receptors in the liver of normal and decapitated rabbit foetuses.

The affinity and the number of receptor sites for the synthetic steroid triamcinolone acetonide were studied in the livers of foetal rabbits. Twenty-two-, 24- and 29-day-old control and 29-day-old foetuses decapitated on day 22 were used to determine whether a change in steroid receptors occurs in the liver when it accumulates glycogen, and whether decapitation impairs such a change. Steroid receptors were found as early as day 22, when they were as numerous (0.091 pmol/mg protein) as on days 24 (0.098 pmol/mg) and 29 (0.104 pmol/mg). The binding affinity was found to be slightly higher on day 24 than on day 22 and it remained the same on days 24 and 29. The binding affinity of the receptors was the same in decapitated foetuses as in 29-day-old controls but the number of sites was slightly lower. The labelled steroid was transferred to the nucleus of the liver cells in vivo. It seems unlikely that steroid receptors are the limiting factor preventing the accumulation of glycogen in the liver of the rabbit foetus before day 26 or after decapitation.

Animals↗

[Echocardiographic findings in the papyraceous right ventricle syndrome].

The echocardiographic findings in a young man with a "paper-thin right ventricle" or Uhl's anomaly are reported. The usual signs of right ventricular diastolic overload with slight delay in tricuspid valve closure were observed. The discordance between the normal clinical examination and the pathological appearances on echocardiography led to cardiac catheterisation which established the diagnosis.

Adolescent↗

Turnover of liver glycogen in the rat foetus.

Incorporation and release of the radioactivity in the liver glycogen of 18.5- and 19.5-day-old rat foetuses were studied after intravenous injection of E11-14C]glycerol. Incorporation occurred during 1 h after injection of the radioactive tracer to the foetus; then, the incorporated radioactivity decreased. Glycogen content in the liver, and glycogen phosphorylase and glycogen synthase were not modified during the experiment. It is therefore postulated that a physiological turnover of glycogen exists in the liver of the rat foetus.

Animals↗

[The role of maternal parathyroids and vitamin D3 metabolites in fetal growth and the deposition of glycogen reserves in the maternal and fetal liver in rats].

Thyro-parathyroidectomy of pregnant Rats at 12.5 days of gestation decreased maternal liver glycogen on 21.5 days of gestation and fetal weight as well as fetal liver glycogen stores. The graft of one parathyroid gland or the injection of 1 alpha-hydroxycholecalciferol in these thyro-parathyroidectomized mothers increased their liver glycogen stores at 21.5 days of gestation. These treatments also markedly increased both fetal weight and fetal liver glycogen stores. It was concluded that maternal 1,25-dihydorxycholecalciferol, which is synthesized under the control of parathyroid hormone secretion, controls fetal growth and liver glycogen stores. The mechanism of these effects (direct or indirect) requires further investigations.

Animals↗

Residues of Dacthal herbicide in carrots.

Residues of Dacthal and its monoacid and diacid hydrolytic ester cleavage metabolites were determined in carrots to which the herbicide was applied on seven plot locations throughout the United States. Residue levels of Dacthal appeared more closely related to the rate of application than to other field parameters. Traces of the monoacid metabolite were found in a few samples. The diacid metabolite was not detected in any of the samples.

Herbicides↗

Modification of methylmercury neurotoxicity by vitamin E.

The protective effect of vitamin E on the neurotoxicity of methylmercury was investigated by means of light and electron microscopy. Young male golden hamsters were exposed to 2.0 ppm methylmercury chloride with or without concurrent administration of vitamin E (2.0 ppm). No toxic symptoms were observed in the vitamin E-protected animals while all the animals given methylmercury alone developed severe symptoms of methylmercury poisoning. Light microscopy revealed no significant neural damage by mercury in those animals exposed to methylmercury/vitamin E while significant neuronal necrosis could be demonstrated in both the cerebellum and calcarine cortex of the methylmercury-treated animals. Besides some accumulation of lysosomes, electron microscopy also demonstrated remarkable intactness of the cellular organelles in the nerve cells without neuronal necrosis. It appears that vitamin E has a strong protective potential against the toxicity of methylmercury.

Animals↗

Toxicity to fish of flame retardant fabrics immersed in their water. Part I.

A number of commercial and candidate flame retardants were studied with regard to their toxicity to fish when released from fabrics immersed in their water. Immersion of laundered or unlaundered flame retardant 100% polyester or polyester blend fabrics used in children's sleepwear in water containing goldfish resulted in release of the anticholin-esterase flame retardant TDBPP (tris (2, 3-dibromopropyl) phosphate) and death of all fish within 24 hours. TDBPP undergoes loss of HBr in water and production of a metabolite.

Animals↗

Fetal metabolic response to maternal fasting in the rat.

To determine the fetal response to altered maternal fuel supply, the effects of prolonged maternal fasting, begun 24-96 h before term, were examined and compared with values from normally fed term animals. Fetal weight decreased only after 48 h of maternal fasting. Prolonged maternal fasting was associated with low blood glucose, high blood ketone bodies, and decreased gluconeogenic substrate in the fetus. Plasma insulin was decreased, whereas plasma glucagon was increased in the fetus of fasted mothers. Infusion of [2-3H]glucose into the mother to constant specific activity gave a ratio of maternal to fetal glucose activity of 1.0 in fed and 1.56 in fasted mothers. Fetal liver from fasted mothers showed both increase in activity of key gluconeogenic enzymes (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase) and increased conversion in vitro of lactate, alanine, serine, and glycerol in glucose by liver slices. It is inferred that maternal fasting induces fetal substrate alterations and hormonal changes appropriate to premature appearance of hepatic gluconeogenesis. The priority for endogenous fuel provision in this state leads to impaired fetal growth.

Amino Acids↗

Glycerol metabolism in the pregnant and virgin rats.

The parameters of in vivo glycerol kinetic curves were determined after a single injection of glycerol-1-14 C in pregnant and in virgin rats. The half-life of glycerol was found to be 9 min in pregnant rats and 17 min in virgin rats. There was no significant difference between the absolute turnover rates. The glycerol plasma space cannot be appreciated. The distribution volume expressed in milliliter of plasma appeared to be very high indicating that glycerol was not distributed only in the plasma. Glycerol was found to be a precursor of glucose and this conversion seemed to proceed more rapidly in the pregnant rat than in the virgin rat.

Animals↗

Hyperglycemia and glycogen storage in the rabbit fetal liver. Role of age and hormonal status.

A 2-hour glucose infusion to pregnant rabbits resulted in fetal hyperglycemia. The question was studied whether this hyperglycemia would induce an increase in the concentration of glycogen in the fetal liver. The result depended upon the age of the fetus. In 24- or 25-day-old fetuses hyperglycemia did not increase the liver glycogen. On the contrary, on day 26, 27 and 28, the glycogen content in the liver was approximately twice as high as in controls. However, in fetuses which were decapitated on day 24 and studied on day 26, the maternal glucose infusion did not increase the glycogen stores. But in those fetuses decapitated on day 25 hyperglycemia provoked glycogen deposition. The activity of liver glycogen synthetase (active form alpha and total form a + b) increased between days 24 and 28 in control fetuses. Some increase of the alpha form already occurs between days 24 and 25. In fetuses decapitated on day 23, the alpha form was found almost as low on day 31 as it was on day 23. The incapacity of the liver of fetuses under 26 days of age or of those decapitated before day 25 to store glycogen under conditions of hyperglycemia probably results from a low glycogen synthetase activity.

Animals↗

Origin and metabolic fate of plasma glycerol in the rat and rabbit fetus.

On day 21.5 a pregnant rat received a single injection of [1-14C]glycerol. The purpose was to study the transfer of glycerol through the placenta from the maternal to fetal plasma. From 3-20 min after injection the specific activity of glycerol in maternal and fetal plasma was measured. The results indicate that the mother can provide this molecule to the fetus. Similar results were obtained with the rabbit on day 28 of pregnancy. The possibility of the conversion of plasma glycerol to glucose has been investigated in the rat and rabbit fetus. This molecule was chosen chiefly to see whether the gluconeogenic pathway was functioning in the fetus above the triose phosphate step. At two stages of fetal development the capacity of the fetus to incorporate [1-14C]glycerol into glucose plus glycogen has been shown in the two species. In the rat fetus the conversion of [1-14C]glycerol to [14C]glucose increases from 19.5 to 21.5 days of gestation. For the rabbit this parameter increases from 25 to 28 days of gestation. On day 25 in the rabbit and day 19.5 in the rat the liver glycogen was labeled, but it did not accumulate the [14C]glucose from [1-14C]glycerol during the time that we have studied. In contrast, on day 28 in the rabbit and day 21.5 in the rat the incorporation of radioactivity increased as function of the time. However, the relative importance of glycerol as precursor of the glucose plus glycogen in the fetus remains to be elucidated.

Animals↗

The effects of narcotics on fetal acid base status.

This paper reports two randomized control trials on the effects of nalorphine, pethidine, morphine and heroin on fetal and maternal acid base status. The drugs decreased pH and increased pCO2 in the mother, and decreased pH and base excess in the fetus. The changes in the fetus were independent of the changes in the mother. In equivalent dosages, nalorphine increased maternal pCO2 more than pethidine and morphine. The effects of heroin were found to be greater than that of other drugs, and we suggest that heroin should be avoided where the fetus is already at risk.

Acid-Base Equilibrium↗