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Biomedical subjects

T V Persaud

Publications and source records attributed to T V Persaud.

At least 37 records · Page 2Linked to original sources
PubMed1991

Chick embryonic development following exposure to ethanol, gamma-linolenic and linolenic acids.

Whether the embryopathic effects of ethanol are due to a deficiency of gamma-linolenic acid (GLA) or its metabolites was investigated by treating chick embryo with ethanol together with efamol, a rich and natural source of GLA. In contrast to findings in the rat, efamol did not protect the chick embryo from the deleterious action of ethanol. This might be due to species differences and the inability of the early chick embryo to metabolize the precursor fatty acids.

Animals↗
PubMed1991

Intrauterine development in the rat following continuous exposure to nicotine from gestational day 6 through 12.

Cigarette smoking during pregnancy is associated with various perinatal complications, but the range of vulnerability to the embryo has not been fully characterized. The effects, in vivo, of continuous exposure to nicotine on postimplantation embryos, were investigated in the rat. Osmotic minipumps, implanted subcutaneously, were used to deliver the nicotine (75 and 150 micrograms/hr) from gestational day 6 through 12, 14 of 16 developmental endpoints, including embryonic growth, were significantly retarded; dysmorphogenesis was not observed. The results reveal that most embryological primordial lagged significantly in their development, following exposure to nicotine during early gestation.

Animals↗
PubMed1990

The pregnant woman in the work place: potential embryopathic risks.

Many women of childbearing age now work in an environment that is associated with reproductive and teratogenic risks. Problems relating to the assessment and control of potential teratogenic hazards in the work place are discussed in this paper. Risk factors include industrial solvents, air pollution, water pollution, noise, anesthetic agents, and video display terminals.

Air Pollution↗
PubMed1989

Influence of 13-cis and all-trans retinoic acid on rat embryonic development in vitro: correlation with isomerisation and drug transfer to the embryo.

In vitro experiments using whole rat embryo cultures show that all-trans retinoic acid (all-trans RA) administered at low concentrations (30 ng/ml culture medium) is 10 times more active than 13-cis retinoic acid (13-cis RA) and 3 times more active when administered at high concentrations (1000 ng/ml culture medium). Morphological investigation of the embryos shows that both substances directly influence embryonic development in an identical manner. Isomerisation products of the administered compounds (all-trans RA from 13-cis RA and vice versa) were detected by HPLC both in the culture medium and the embryo. Correlation of embryonic retinoid concentration with the observed effects led us to suggest that the isomerisation to all-trans RA is crucial in regard to 13-cis RA-induced abnormal embryonic development. A 100% effect can be induced in vitro with very low amounts of all-trans RA (7.2 ng/g) in the embryo.

Animals↗
PubMed1989

Relationship of embryotoxicity to genotoxicity of lead nitrate in mice.

Frequency of sister chromatid exchanges (SCEs), nucleolar organizing regions (NORs) and chromosomal aberrations were analysed, in maternal bone marrow and fetal liver and/or lung cells of ICR Swiss Webster mice, following maternal exposure to lead nitrate on gestational day 9. The number of implantations and morphological changes in day 18 fetuses, following the treatment, were also noted. Chemical analysis of lead in maternal and fetal tissues showed that it is readily transferred across the placenta. Lead caused a moderate, but statistically significant, increase in the frequency of SCEs in maternal bone marrow cells and significant reduction in NORs at the 2 highest dose levels (150 and 200 mg/kg b.w.). Lead treated animals showed several specific chromosomal aberrations, mostly deletions in maternal bone marrow and fetal cells. Aneuploidy was found to be frequently associated with the lowest dose levels of lead nitrate (100 mg/kg). Maternal treatment with lead nitrate also significantly increased embryonic resorptions and reduced placental weights. The results suggest that the embryotoxic effects of lead might be associated with the chromosomal changes.

Animals↗
PubMed1989

Embryotoxicity and in vivo cytogenetic changes following maternal exposure to cadmium chloride in mice.

Cadmium is a well-known teratogen in laboratory animals and a widespread environmental pollutant. The frequencies of sister chromatid exchanges (SCEs), nucleolar organizing regions (NORs) and chromosomal aberrations were analysed in maternal bone marrow and fetal liver and/or lung cells of mice, following maternal treatment with cadmium chloride, on gestational days 8 through 10. The embryotoxic effects and morphological changes on day 18 fetuses were also studied. Cadmium chloride is readily transferred across the placenta and significant levels were detected in both the placenta and fetus. No significant changes in the frequencies of SCEs or NORs in maternal and fetal cells were observed following exposure to cadmium chloride. Fetal tissues showed mitotic inhibition at the highest dose levels (8.4 and 11.4 mg/kg, b.w.). Maternal treatment with cadmium chloride increased embryonic resorptions and fetal lethality, as well as reduced placental weight; however, it did not produce significant chromosomal changes except at the highest dose level (11.4 mg/kg).

Abnormalities, Drug-Induced↗
PubMed1989

Influence of nicotine and caffeine on skeletal development in the rat.

The effects of nicotine and caffeine at dose levels approximating human consumption on skeletal development was investigated in Sprague-Dawley rats. One group of animals received nicotine administered subcutaneously by an Alzet miniosmotic pump from gestational d 6 through 12 (25 mg over 7 d; rate 149 micrograms/h). Control animals received physiological saline in a similar manner. A2. group received a single intravenous injection of caffeine (25 mg/kg) on gestational d 6. Control animals were treated with physiological saline. A further group received both nicotine and caffeine on gestational d 6 as described for the 2 previous groups. Evaluation of the fetal skeletal system on gestational d 20 revealed a significant decrease in the number of complete sternal ossification centers, as well as delays in the ossification of the skull and face, following combined nicotine and caffeine treatment. Other skeletal anomalies and variations were frequently observed, but their incidences were not significantly increased in any of the treatment groups, compared to the corresponding controls. A coteratogenic effect is evident between nicotine and caffeine on account of the increased incidence of delayed and abnormal skeletal development.

Animals↗
PubMed1988

Neuropathology of congenital hydrocephalus in the SUMS/NP mouse.

The neuropathology of congenital hydrocephalus in SUMS/NP mice was investigated in this study. Hydrocephalus occurred with an incidence of 16.5% and was evident in the form of an enlarged head soon after birth. The condition was progressive; affected mice gradually became noticeably smaller than normals, acquired functional disturbances and died before ever breeding. Hydrocephalic mice exhibited enormous dilatation of the lateral ventricles, thinning of the cortex and compression and distortion of the diencephalon and striatum. Examination of the midbrain in these animals revealed that the proximal cerebral aqueduct was diminished in size, occluded or absent. Evidence of its anomalous development was seen as early as day 15 of foetal development. This is in substantial agreement with previous reports on this strain. Although the mechanism by which this occurs is still unknown, abnormal development of the adjoining diencephalon and/or rostral midbrain is likely to be involved.

Age Factors↗
PubMed1988

Mechanisms of fetal alcohol effects: role of acetaldehyde.

Pregnant rats were treated from day 9 through 12 of gestation with 12.5% ethanol, 25% ethanol, 1% acetaldehyde, cyanamide (an inhibitor of the enzyme aldehyde dehydrogenase), or a combination of cyanamide and ethanol. Embryos were recovered on gestational day 12 and were quantitatively assessed on the basis of 16 recognizable developmental endpoints (morphological scores). The head and the crown-rump lengths of the embryos were also measured. Total resorption occurred in two animals treated with cyanamide and two treated with cyanamide and ethanol. Acetaldehyde and ethanol (at both concentrations) were found to reduce the head length of the embryos but had no significant effects on morphological scores and crown-rump length. The combination of ethanol with cyanamide caused a greater reduction in head length and also significantly reduced crown-rump length, as well as the morphological scores. The results suggest that the deleterious effects of ethanol could be attributed to acetaldehyde, its primary metabolite, although other underlying factors cannot be ruled out.

Acetaldehyde↗
PubMed1988

Hereditary hydrocephalus in laboratory animals and humans.

Cerebral ventricle dilatation secondary to disturbed flow of CSF has been observed as an inheritable trait in a variety of laboratory animals as well as in humans. In few groups, however, has the neuropathology been adequately elucidated. In most cases, defective development of the cerebral aqueduct or of the subarachnoid space has been observed. Further study is needed to understand the developmental mechanisms that fail and give rise to hydrocephalus in such models.

Animals↗
PubMed1988

Embryopathic risks of cigarette smoking.

Cigarette smoking has been associated with infertility, a higher frequency of spontaneous abortions, intrauterine growth retardation and an increased incidence of birth defects. Nicotine is the major pharmacological component of cigarette smoke. Its potential reproductive and teratological risks are critically reviewed.

Abnormalities, Drug-Induced↗
PubMed1988

Rat embryogenesis following exposure to alcohol and nicotine.

Pregnant Sprague-Dawley rats were treated from day 9 through 12 of gestation with either ethanol (12.5% v/v in physiological saline, 0.015 ml/g, i.p.) and nicotine (16.7 mg/kg, s.c.), alone or in combination. Corresponding groups of animals received physiological saline in a similar manner and these served as controls. Embryos were recovered on gestational day 12 and were quantitatively assessed on the basis of 16 recognizable developmental endpoints (morphological scores). The head and the crown-rump lengths of the embryos were also measured. Embryos exposed to nicotine and to ethanol-nicotine were significantly affected in their development whereas those exposed to ethanol alone were spared.

Alcohol Drinking↗
PubMed1988

Influence of nicotine and caffeine on rat embryonic development.

The influence on embryonic development of nicotine and caffeine at dose levels approximating human consumption was investigated in Sprague-Dawley rats. One group of animals received nicotine administered subcutaneously by an Alzet mini-osmotic pump from gestational day 6 through 12 (25 mg over 7 days; rate 149 micrograms/hr). Control animals received physiological saline in a similar manner. A second group received a single intravenous injection of caffeine (25 mg/kg) on gestational day 6. Control animals were treated with physiological saline. A further group received both nicotine and caffeine on gestational day 6 as described for the two previous groups. There were no significant differences among any of the groups with respect to maternal weight gain, litter size, embryolethality, fetal weight, or crown-rump length. The offspring of nicotine treated animals showed a significantly higher incidence of hydrocephaly when compared to the controls, but in the combined treatment group no malformed fetuses were observed. Light microscopic examination of maternal liver, kidney and placentas revealed changes in the hepatic sinusoids, glomeruli and intervillous spaces after nicotine and combined treatment. In addition, the decidua basalis was poorly developed compared to the controls. Chorionic villi and fetal kidney appeared normal in all groups. A coteratogenic effect is not evident from these findings.

Animals↗
PubMed1988

Reproductive and teratological risks of caffeine.

Because caffeine might be harmful to the fetus, the Food and Drug Administration of the United States recently urged that "pregnant women should avoid caffeine-containing food and drugs, if possible, or consume them sparingly". In this paper, the potential reproductive and teratological risks of caffeine are briefly reviewed.

Abnormalities, Drug-Induced↗
PubMed1988

Historical documents concerning craniopagi and conjoined twins.

The occurrence of congenital malformations had been documented by the Assyrian and Babylonians about 2,800 B.C. Historically, a significant source of information concerning conjoined twins were the so called "fugitive sheets" which following the introduction of printing served to disseminate news. The first sonographs with descriptions of congenital defects in human and animals appeared during the 17th century. Teratology became established during the 19th century as a result of the fundamental discoveries in embryology. Significant impetus was given to teratological research in this century following the discovery of GREGG (1941), from observations of the children born to pregnant women who were exposed to the atomic bombs, as well as the thalidomide catastrophe.

Abnormalities, Severe Teratoid↗