A comparison of neurotoxicity in cerebellum produced by dermal application of chlorpyrifos in young and adult mice.

Chlorpyrifos (CPF), an organophosphate pesticide inhibits acetylcholinesterase (AChE) and causes neuromuscular incoordination among children and elderly. The objectives of the present study were to compare the neurotoxic effects of dermal application of CPF on the cerebellum in the parameters of glial fibrillary acidic protein (GFAP) expression in young and adult mice and to correlate with the changes in acetylcholinesterase levels. Male Balb/c mice, 150 days old (adult) and 18 days old (young) were dermally applied with ½ LD(50) of CPF over the tails for 14 days. Serum AChE concentration was estimated and GFAP immunostaining was performed on sagittal paraffin sections through the vermis of cerebellum. Although reduced in both age-groups exposed to CPF, percentage of reduction in serum AChE was more in adult compared to the young. Under GFAP immunostaining, brown colour fibres and glial cells were observed in cerebellar cortex and medulla in both the experimental groups. The mean GFAP-positive glial cell count in cerebellar medulla per mm(2) of section was significantly (p < 0.05) increased in adult mice exposed to CPF when compared with age-matched control. In conclusion, this study confirmed that dermal exposure of CPF was able to exert neurotoxic effect in both young and adult mice. However, the quantitative results revealed that adult mice showed more GFAP expression in cerebellum when compared with the young, when exposed to CPF.

Evaluation of difference in the neurotoxicity produced by dermal application of chlorpyrifos on the neonatal and adult mice.

Dermal exposure to organophosphate pesticide is important because of its popular use. This study planned to compare the changes in serum acetylcholinesterase, paraoxonase and neuronal density of hippocampus and iso-cortex between two age groups of Swiss albino mice (18-day-old and 150-day-old) after dermal application of (1/2) LD50 of chlorpyrifos for 14 days. Statistically significant reduction was observed in serum acetylcholinesterase (Mann-Whitney test, p<0.05) and neuronal density (Independent samples t-test, p<0.05) in exposed groups compared to the control. The reduction in serum AChE and neuronal density was more pronounced in exposed adult mice than in exposed neonatal mice. The paraoxonase level was insignificant in control neonatal mice, whereas it was 890-fold more in exposed neonatal mice. Upregulated paraoxonase levels may be extrapolated to produce relatively lower reduction of cholinesterase and neuronal density in neonatal mice.

Effect of alcohol on neurons of iso-cortex--a histomorphometric study.

Effect of chronic intake of alcohol and its subsequent withdrawal was studied in albino mice on the layers of neurons of the iso-cortex. Neuronal density per mm2 of section in different layers of iso-cortex was counted and compared in 3 groups of animals (control, ethanol fed and withdrawal). Qualitative changes on nissl granules of neurons and myelinated fibres were also studied. Mice fed with 10% ethanol v/v ad libitum for 6 months showed loss of nissl granules and nucleolus and discontinuity of nuclear membrane. Quantitatively, significant reduction in neuronal density (P<0.001) was observed in layers II+III IV and V neurons of iso-cortex. Withdrawal of ethanol for 2 months showed continued reduction of counts of neuronal density in layers II+III and V only whereas reversal of count was found significantly (P<0.001) in layer IV of iso-cortex. Qualitatively, only few neurons showed prominent nissl granules after withdrawal of ethanol. More afferent synaptic connection in layer IV may be suggested as probable factor helping relative replenishment of neuronal count after withdrawal of alcohol.

Evaluation of vitamin A status during pregnancy.

Adequate maternal vitamin A nutrition is essential for successful pregnancy outcome and estimation of serum retinol among pregnant women enables a precise and objective assessment of vitamin A status, during pregnancy, even in subclinical state. In order to evaluate vitamin A status during pregnancy, and its relationship with personal and pregnancy related variables of the mother, 300 antenatal clinic attenders were interviewed at RG Kar Medical College and Hospital, Calcutta and tested for serum retinol, using Carr-Price test. Serum retinol values less than 30 microg/dl and 20 microg/dl, in this study, were considered as poor and severe vitamin A deficiency respectively. According to this 14.7% and 4% pregnant women were found to be suffering from poor and severe vitamin A deficiency respectively. Clinical signs of vitamin A deficiency (eg, nightblindness) were reported only among 60% cases of the deficient population. The problems of vitamin A deficiency were associated with low literacy and poor nutritional status of the mother, advanced gestational age of current pregnancy,increased number of pregnancies, shorter interval between births and poor dietary intake of vitamin A rich foods during pregnancy. The study thus raises the question of supplementation of vitamin A, during pregnancy, in Indian context where habitual diets are either inadequate or deficient in vitamin A.

Missed opportunities for immunisation in children.

All opportunities for immunisation in children should be utilised properly, as sustaining high levels of full immunisation coverage is essential to meet the goal of eradication of poliomyelitis as well as control the other vaccine-preventable diseases; yet many opportunities for immunisation are missed in all types of health facilities, even in teaching hospitals. Reducing such missed opportunities is the cheapest way to increase immunisation coverage. The present study discusses the problem of missed opportunities for immunisation in children in Paediatric Outpatient Department and Immunisation Clinic of R.G. Kar Medical and Hospital, Calcutta and the underlying factors of the problem. Prevalence of missed opportunities in Paediatric OPD and Immunisation clinic was 37.8% and 1.4% respectively. Most of the missed opportunities were attributed to health care providers and delivery system of health care of the studied hospital.

Emerging Plasmodium falciparum in an endemic area in Calcutta.

Calcutta is now intensely malarious. Malarial infections are detected in every month. In an endemic area in central Calcutta a year-long study from August 1996 to July 1997 reveals that 31.47% of all cases are due to Plasmodium falciparum infection. A competition is going on between P vivax and P falciparum to gain upperhand. An equilibrium is there in the month of January (1997), when P vivax and P falciparum cases constitute 51.13% and 49.43% respectively. The highest and lowest percentage of P falciparum infection is in December 1996 (67.98%) and in May 1997 (0.89%) which is just reverse in the case of P vivax in December 1996 (33.60%) and in May 1997 (99.10%). Three imported cases of P malariae have been detected but the patients cannot be traced. Six cases of mixed infections have been found.

The effect of malnutrition on placenta.

Effect of malnutrition was studied on placentas of eighty-five malnourished mothers, taking the placentas of sixty-five well nourished mothers as control. Nutritional status of mothers were studied by estimation of haemoglobin, total R.B.C. count and serum protein. Mothers of the malnourished group, showed anaemia of normocytic, microcytic, a few macrocytic type and hypoproteinaemia. Their placentas were of lower weights and sizes than those of control group. Placentas of both the groups showed infarction, degenerative, calcification, fibrinoid necrosis of villi, intervillous fibrin deposition, villous fibrosis, syncytial knotting of villi and proliferation of Langhan's cell of the villi. But the extent and degree of these changes were much more in malnourished group than control group. Activities of the enzyme such as alkaline phosphatase and Glucose-6-phosphatase in placental villi were increased in malnourished group than those in control group. So it appears that placentas of malnourished mothers become underdeveloped having pathological changes greater in extent and degree than control group resulting in inadequate supply of nutrients from mother's blood to foetus blood.