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Biomedical subjects

C Singh

Publications and source records attributed to C Singh.

At least 55 records · Page 3Linked to original sources
PubMed1989

Zinc protects testicular injury induced by concurrent exposure to cadmium and lead in rats.

The effect of coexposure to lead and cadmium (each 50 ppm alone and 25 ppm in combination) on the testes of rats and the preventive role of zinc (50 ppm) was investigated by administering these metals through drinking water. Male weaned albino rats were exposed to these metals for 120 days. Testicular histology, sperm counts and sperm motility were studied in these rats. The animals coexposed to lead and cadmium exhibited much more pronounced pathological changes and reduced sperm counts compared to the animals exposed to either of the metals alone. Zinc supplementation to the lead + cadmium exposed rats revealed the protective effect of zinc on these parameters. The observed higher magnitude of changes in the testes of lead + cadmium exposed group seems to be due to the excessive cadmium accumulation.

Animals↗
PubMed1988

Effects of sodium deoxycholate on the mechanical and electrical activities and ultrastructure of guinea pig atria.

The mechanism of cardio-inhibitory effects of sodium deoxycholate (DOC) was investigated by studying its effects on the contractility, action potentials (APs) and ultrastructure of guinea pig atrial preparations. DOC (10(-7)-10(-4) M) caused reversible negative ino- (NIE) and chrono-tropy in spontaneously beating (SBA) and NIE in electrically driven left (EDA) atria. At higher doses (greater than or equal to 1.10(-3) M) DOC caused irreversible inhibition of contractions. Atropine (10(-7)-10(-4) M) failed to inhibit both the reversible and irreversible effects of DOC. The NIE due to lower doses of DOC (less than or equal to 1.10(-4) M) was inhibited by higher [Ca2+]0, isoprenaline (10(-6)-10(-4) M), and noradrenaline (10(-6)-10(-5) M), which did not alter the dose of DOC required for the irreversible and complete NIE. In lower doses (10(-7)-10(-4) M) DOC caused a reversible inhibition of the AP durations at -20 and -40 mV (APD20 and APD40, respectively), but increased the AP duration at 90% repolarisation (APD90). At higher doses (greater than 5.10(-4) M) it caused an irreversible membrane depolarization, reduction in APD20 and APD40, and complete cessation of electrical activity. The ultrastructural changes in atria treated with 1.10(-4) M DOC were characterized by poorly delineated glycocalyx and at greater than 1.10(-3) M by disruption of sarcolemma and sarcoplasmic reticulum and swelling disruption of mitochondria. Taken together these observations show that DOC caused reversible and irreversible inhibition of atrial contractions at low (10(-7)-10(-4) M) and high (greater than 5.10(-4) M) concentrations, respectively, by different mechanisms. The former effect is due to inhibition of Ca2+ channel activity and the latter due to its detergent property causing removal of subcellular components.

Action Potentials↗
PubMed1986

Study of vaginal delivery in patients with one previous lower segment caesarean section.

This retrospective study evaluated the prospects of having a vaginal delivery following a lower segment Caesarean section in Nehru Hospital; 685 (52%) of 1,315 patients with a previous Caesarean section were given a trial of vaginal delivery with a success rate of 69%. Vaginal breech delivery was allowed in 14 patients without affecting the outcome of term babies and without maternal morbidity or mortality. There were 12 cases (1.7% incidence) of scar disruption of which 4 were of scar rupture. There was no maternal or fetal death as a result of these disruptions even though 3 mothers had subtotal hysterectomy. Pitocin was used in 144 (21%) patients. Of the 12 cases of scar disruption 5 patients had received pitocin. There was no favourable influence of prior vaginal delivery on the success of the trial, and 3 patients with scar disruption had already had a vaginal delivery in addition to a lower segment Caesarean section.

Breech Presentation↗
PubMed1985

Caffeine potentiation of propane sultone mutagenesis in barley.

Pre- and post-treatments with caffeine enhanced propane sultone (PS)-induced growth damage in barley. The caffeine post-treatments were, however, more effective in potentiating PS-induced growth damage and caused an additive effect on the frequency of chlorophyll mutations.

Caffeine↗
PubMed1984

Effects of couple stresses on the blood flow through an artery with mild stenosis.

An analysis of the effects of couple stresses on the blood flow through thin artery in the presence of very mild stenosis has been carried out with the help of two nondimensional parameters, alpha (the length ratio parameter) and eta (the parameter characterizing the antisymmetric property of the couple stress tensor). It is shown that an increase in the couple stress (small value of alpha and eta), increases the resistance to the flow and the wall shear stress. These characteristics are further enhanced by the presence of the stenosis.

Arteries↗