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Biomedical subjects

R S Tulsi

Publications and source records attributed to R S Tulsi.

29 records · Page 2Linked to original sources
PubMed1975

Observations on the structure of the dorsal muscle in the bottle-nose dolphin (Tursiops truncatus).

The dorsal muscle of five South Australian bottle-nose dolphins has been studied. The ultrastructure and cytochemistry of the red, white and intermediate fibres were essentially similar to those of other mammalian skeletal muscles. Two features of special interest were: (a) the large number of lipid droplets in the red muscle fibres, and (b) the presence of longitudinal tubes linking the transverse tubes of the T-system, both within a sarcomere, and also between adjacent sarcomeres, of the white muscle fibres. The muscle spindles and neuromuscular junctions in the dolphin appeared to be morphologically similar to those of other mammals.

Adenosine Triphosphatases↗
PubMedDate not supplied

The teratogenic effects of nicotine in vitro in rats: a light and electron microscope study.

Cigarette smoking in pregnant women has been shown to lead to intrauterine growth retardation and fetal death, and possibly also to neural dysmorphology and long-term learning deficits in the offspring. Because the teratogenic agent in cigarette smoke remains controversial, the present study on rat embryos in culture examined specifically whether nicotine can cause neural dysmorphology and, hence, act as a nervous system teratogen. This in vitro study confirmed previous reports in utero that nicotine leads to growth retardation, and, in addition, demonstrated that development of the nervous system, particularly the forebrain, as well as the branchial arches was impaired, possibly leading to microcephaly and cleft palate respectively in term fetuses. Cellular disruption and necrosis occurred in the neuroepithelium and underlying mesenchyme, with the effect being dose dependent. Ultrastructurally, there was severe disruption of cell and organelle membranes, with many healthy cells containing engulfed, whole condensed or remnants of dead cells. This study demonstrates that nicotine acts as a nervous system teratogen leading to gross and cellular dysmorphology. Suggested mechanisms for nicotine action include the possibility that the highly lipid soluble teratogen may exert its effects directly on the membranes or indirectly through oxidative membrane damage.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

The suprahabenular recess in the rat: a quantitative study of ciliated cells, supraependymal cells and some specific features of supraependymal fibres.

Using light microscopy, scanning and transmission electron microscopy, an extensive quantitative analysis of ciliated ependymal cells, supraependymal cells and supraependymal fibres in the suprahabenular recess of twenty-two adult Wistar rats was carried out. In addition, six animals were used to determine the origin of supraependymal fibres and their relationship to ependyma. The findings were as follows: ciliated cells-mean 3.32 +/- 0.26 per 1000 micron 2 (range 0-10); supraependymal cells-5.91 +/- 1.37 per recess (range 2-16). Average number of cilia per cell in different animals ranged from 31 to 33. Sex did not influence the density of ciliated ependyma or supraependymal cells. Evidence was obtained that some supraependymal fibres are closely associated with aberrant commissural fibres. The supraependymal fibres enter the suprahabenular recess and form gap junctions, and other types of junctions, with subjacent ependyma.

Animals↗