Early arrivals: association of maternal obstetric factors with preterm births and their survival in India.

OBJECTIVES: Preterm birth (PTB) increases the risk of various acute and chronic morbidities and premature mortality in children under 5 years of age. The present study examines the association between different maternal obstetric factors and PTB. In addition, this study estimates the risk of neonatal mortality among children born preterm. STUDY DESIGN: Retrospective two-stage stratified sample design. METHODS: The weighted prevalence of PTB was estimated using data on 148,746 most recent institutional births from the National Family Health Survey (NFHS)-4, 2015-16. The Poisson regression model was used to investigate the association between maternal obstetric factors and PTB. Using Cox's proportional hazard model, the risk of neonatal mortality among PTBs was estimated. RESULTS: Maternal obstetric factors, such as minimal antenatal care, delivery complications, history of previous caesarean delivery and delivery at private health facilities, were significantly associated with an increased risk of PTB. The survival probability of preterm babies sharply declined in the first week of life and thereafter was found to stabilise. The risk of mortality in the first 28 days of life increased 2.5-fold if the baby was born preterm. Optimising antenatal care was found to lower the likelihood of PTB and improve their chances of survival. CONCLUSION: Antenatal care services and delivery care practices in private facilities were strongly associated with the incidence and survival of PTB. Evaluating associations of history of caesarean births on future pregnancies can help understand their deleterious effects on PTB. Affordable, accessible and available antenatal care services, in both public and private facilities, can increase the survival rates of PTBs.

Genotoxic potential of arsenic at its reference dose.

Arsenic, a highly hazardous contaminant in our drinking water, accounts for various toxic effects (including cancer) in human. However, intake of arsenic @0.3 µg kg(-1)day(-1) through drinking water, containing arsenic at its guideline value or maximum contaminant limit (10 µg L(-1)), has been estimated to pose very little or no measurable risk to cancer in humans. The value also appears to be equal to the human reference dose (or index dose) of arsenic based on human skin toxicity data. The present work was a quantitative assessment of the genotoxic potential of arsenic in mice at doses equivalent to its human reference dose as well as its multiples. Significant increases in the frequencies of chromosome abnormalities in the bone marrow cells were registered over the control level upon exposure to all the doses of arsenic including its reference dose (or index dose). The assessment of arsenic genotoxicity in humans at low doses will therefore be highly instrumental in establishing a permissible limit of arsenic in drinking water.

Antimutagenic profile of antioxidant vitamins in drosophila mulation test.

OBJECTIVE: To assess the antimutagenicity of antioxidant vitamins (vitamins A, C, and E) as expressed by their efficacy to lower aflatoxin-induced mutations. METHODS: The Muller-5 method for mutation detection was used to assay the frequency of X-chromosome linked recessive lethal mutations (XRLMs) in Drosophila. Larvae were exposed to dietary concentration of aflatoxins and/or the human therapeutic doses of any of the three antioxidant vitamins. Absence of normal eyed males among M2 progeny gave an indication of mutation induction. RESULTS: Aflatoxin supplimentation significantly increased the incidence of XRLMs in Drosophila. Mutation frequency was also raised a little above the control level in case of vitamin treatment. However, notable mitigation in mutation frequency was registered when aflatoxin-treated larvae were concomitantly fed with any of the three antioxidant vitamins. CONCLUSION: Aflatoxin exposure can enhance the frequency of gene mutation in Drosophila which is significantly lowered by each of the three antioxidant vitamins. The degree of amelioration produced by them is almost identical. This mitigation is based on the scavenging/trapping by antioxidant vitamins of DNA-reactive products (metabolites and radicals) emanating from aflatoxin metabolism.

Genotoxicity of nimesulide in murine bone marrow cells.

The genotoxic potentiality of nimesulide was evaluated in vivo in murine bone marrow cells. The human equivalent prophylactic dose of nimesulide (5 mg/kg body wt/day) was given to animals orally, once daily for seven consecutive days. Metaphase chromosome analyses revealed the significant increase in the incidence of chromosomal aberrations with preference to structural over the numerical ones. It therefore suggested the clastogenic effect of the nimesulide. The molecular mechanism of mutagenesis is yet to be determined.

Cytogenetic toxicity of neem.

The cytogenetic toxicity of the leaf extract of neem was evaluated in murine germ cells. The extract was found to induce structural and numerical changes in the spermatocyte chromosomes as well as synaptic disturbances in them at their first metaphase. A significant increase in the frequency of sperms with abnormal head morphology and the decrease in mean sperm count were also observed. This spermatotoxic effect of the neem extract corroborates its germ cell mutagenicity. The possible role of azadirachtin, the most active principle present in the neem extract, in producing the observed genotoxic effect is discussed.

Differential genotoxicity of the crude leaf extract of a medicinal plant, Casearia tomentosa.

The genotoxic potentiality of the crude leaf extract of Casearia tomentosa, a medicinal preparation, has been evaluated in Swiss albino mice. The extract significantly induced the division-disruptive chromosomal changes in bone marrow cells as well as in primary spermatocytes; the latter also exhibited marked increase in synaptic disruptions. A significant decrease in sperm count was noted. The incidence of structural damages in chromosomes, however, remained within the range of control level frequency. This herbal preparation, therefore, appears to be primarily spindle-poisoning in its action, but not clastogenic. The probable mechanism of this differential genotoxicity is discussed.

Anticlastogenicity of vitamin C in vivo against the cytogenetic toxicity of muriate of potash in murine bone marrow cells.

The potential in vivo anticlastogenicity of vitamin C was evaluated in murine bone marrow cells against the cytogenetic toxicity of muriate of potash, a synthetic fertilizer. The animals were treated orally once daily for 7 days with muriate of potash (5g/kg) and/or vitamin C (10mg/kg). Metaphase chromosome analyses revealed that muriate of potash induced chromosomal abnormalities were significantly decreased, though still remained higher to control, when vitamin C was administered concurrently. The possible role of vitamin C in mitigating the muriate of potash induced cytogenetic toxicity is discussed.

Ameliorating effect of vitamin C on murine sperm toxicity induced by three pesticides (endosulfan, phosphamidon and mancozeb).

The ameliorating effect of vitamin C (injected intraperitoneally) was evaluated against changes in sperm count and sperm head morphology in mice fed either 3, 6 or 1000 mg/kg body wt/day endosulfan, phosphamidon or mancozeb, respectively. The animals received aqueous preparations of the pesticides and/or vitamin C once daily for 35 consecutive days. All three pesticides, irrespective of their chemical nature, significantly decreased the sperm count, as well as increased the frequency of sperm with aberrant head morphology. Out of the three doses of vitamin C used the middle and higher ones (20 and 40 mg/kg body wt/day, respectively) afforded comparatively more significant amelioration. The lower dose (10 mg/kg body wt/day) of this vitamin (quantitatively equivalent to the human therapeutic dose according to body weight) was least efficacious in both the tests. However, amelioration was never up to the control level in any case. Vitamin C doses, when administered alone, did not produce any adverse effect on sperm count and sperm head morphology.

Cytogenetic toxicity and no-effect limit dose of pesticides.

The no-effect limit dose (NELD) of three commonly used pesticides with respect to their cytogenetic toxicity was determined in a number of test systems using a sufficient number of lower doses to characterize the dose-effect relationship. For lindane, malathion and metacid, this dose was 3.2, 7.0 and 3.0 mg/litre, respectively, for mitosis inhibition and 9.0, 55 and 60 mg/litre, respectively, for chromosome clastogeny in onion root-tip cells. For chromosome clastogeny in mice bone marrow cells, the NELDs of the three pesticides were 1.6, 1.5 and 2.0 mg/kg body weight/day, respectively. These values for dominant lethals and X-chromosome-linked recessive lethals in Drosophila were 20 and 5 micrograms lindane/litre, 2 and 3.5 micrograms malathion/litre and 4 and 5.5 micrograms metacid/litre, respectively. Thus, the NELDs are not only pesticide specific but also organism specific, tissue specific and even damage specific. Furthermore, the NELD values determined are so small that the real human exposure to pesticides cannot be reduced below these levels without compromising the effectiveness of pesticides in use.

Vitamin C mediated amelioration of pesticide genotoxicity in murine spermatocytes.

The effect of vitamin C on the genotoxicity of three pesticides (Endosulfan, Phosphamidon, Mancozeb) was monitored by screening meiotic (metaphase I) chromosomes in the primary spermatocytes of Swiss albino mice, Mus musculus. A dose-dependent amelioration by vitamin C was observed in the Phosphamidon-treated group where quadruple the therapeutic dose produced maximum amelioration. In Endosulfan- and Mancozeb-treated groups, no further amelioration was achieved beyond the double dose of vitamin C, and the damage frequency did not come down to the control level. The possible mechanism of this effect is discussed.

Impact of higher doses of vitamin C in modulating pesticide genotoxicity.

The modulatory effect of higher doses of vitamin C (ascorbic acid) on the genotoxicity of the three pesticides (endosulfan, phosphamidon, and mancozeb) was assessed in the in vivo micronucleus test in Swiss albino mice. Concurrent administration of the vitamin in a dose (20 mg/kg bwt/day) equivalent to double the human therapeutic one, along with each of the three pesticides, was most effective as an antimutagen. The therapeutic dose (10 mg/kg bwt/day) was comparatively less so, and the quadruple (40 mg/kg bwt/day) of it did not show any further amelioration.

Antimutagenic efficacy of higher doses of vitamin C.

Vitamin C, when administered concurrently with a pesticide (endosulfan, phosphamidon or mancozeb), could significantly decrease the frequency of pesticide-induced clastogenic and mitosis-disruptive changes in the bone marrow cells of young Swiss albino mice. Of the three doses (10, 20 or 40 mg/kg b.wt./day) of the vitamin, the one which is double the human therapeutic dose (20 mg/kg b.wt./day) was most effective as an antimutagen to be followed by 40 mg and 10 mg. None of these doses of vitamin C showed any genotoxicity of their own for the parameters studied here.

Evaluation of 496 menstrual regulation and abortion patients in Calcutta.

From March to December 1975, 496 patients were studied to compare the safety and effectiveness of menstrual regulation (MR) performed with a Karman hand syringe and first trimester abortion performed with an electric vacuum aspirator. All procedures were done on an outpatient basis. The complication rate for the MR patients was significantly lower than that for the other first trimester abortion patients. Study results indicate that MR with the Karman syringe is a safer, simpler and less costly procedure than first trimester abortion with the electric vacuum aspirator. Further research and study are necessary to determine the effect of the initial and repeat MR procedures on women's menstrual patterns and future pregnancies, including any subsequent prematurity, stillbirths and Rh immunization.