Air pollution in Calcutta elicits adverse pulmonary reaction in children.

BACKGROUND & OBJECTIVE: Pulmonary responses of children chronically exposed to ambient air pollution in Calcutta have been investigated. METHODS: A total number of 153 children from Calcutta and 116 from rural West Bengal in the age group of 6-17 yr were included in this study. Respiratory symptom complex, sputum cytology and micronucleus (MN) count of buccal epithelial cells were evaluated. Blood smears were examined for WBC differential count and RBC morphology. RESULTS: Marked rise in respiratory symptoms (43% in urban vs 14% in rural) and sputum alveolar macrophage (AM) number was observed in urban children compared to their rural counterparts (14.2 +/- 1.4 AM/hpf vs 6.7 +/- 1.4 AM/hpf, mean +/- SE, P < 0.001). The urban group also demonstrated increased numbers of neutrophils, eosinophils and iron-laden AM in their sputum. Besides, buccal epithelial cells of urban children exhibited higher MN frequency than their rural counterparts (0.22 vs 0.17%, P < 0.05). While sputum neutrophilia and eosinophilia suggest inflammatory and allergic lung reactions, elevated MN count is indicative of greater genotoxic effect on the exposed tissues of urban children. Hypochromic red cells in peripheral blood smear was a common finding in both urban and rural groups, but eosinophils and monocytes were present in elevated frequencies in the rural children. INTERPRETATION & CONCLUSION: The study demonstrated that children inhaling grossly polluted air of Calcutta suffer from adverse lung reactions and genetic abnormality in the exposed tissues.

Studies on the platelet alpha-adrenoceptor subtypes in diabetes mellitus.

Studies on the platelet alpha-adrenoceptor subtypes were carried out in 19 subjects with treated diabetes mellitus and 15 normal age and sex-matched controls. By utilising selective antagonists, it was noted that all the normal human platelets exhibited the alpha-2 adrenoceptor. 7 diabetics (37%) expressed both the alpha-1 and alpha-2 adrenoceptors and diabetic complications along with hypertension were most common in this group. Another 7 diabetics (37%) expressed the alpha-2 receptor only and diabetic complications were minimum in this group. Interestingly, 5 diabetics (26%) did not express either the alpha-1 or alpha-2 receptor and these patients occupied an intermediate position with regard to diabetic complications. Thus, it was concluded that platelet alpha-1 adrenoceptors perhaps indicated a poor prognosis in diabetes mellitus, opening up future scope for work in this area.

Survivability and leucocyte migration inhibition in mice immunized with cryotreated ascites fibrosarcoma cells using different freeze-thaw cycles.

Attempts have been made to assess as to what extent in vitro assay of cellular immunity, e.g. leucocyte migration inhibition (LMI) in mice immunized with different freeze-thaw cycles could reflect host resistance in vivo. While survivability of animals improved significantly by immunization with single cycle (P < 0.05) to three cycle (P < 0.001) and programmed three cycle (P < 0.001) cryo-treated tumor cells compared to controls, the percentage LMI in the same groups of animals decreased progressively. The KCl(3M) extracted tumor cell protein (antigen) of both viable and cryo-treated cells showed a progressively increased protein concentrations per 1 x 10(6) tumor cells with viable cells being least and programmed three cycle cryo-treated cells highest. The apparent discrepancy observed between percentage migration inhibition and survivability may be due to the fact that (1) survivability is a function of body's total immune response while LMI represents the response of one effector limb only; (2) immuno-regulatory mechanisms depend on a balance between activation and suppression and suppressor cells being more sensitive and of shorter life span, affect migration inhibition but not the survivability; (3) cryo-treatment alters tumor cell surface antigen affecting immunological balance; and (4) suppressor and antitumor activities against antigenic stimulation develop simultaneously in different organs and LMI performed with sensitized splenic cells, where, perhaps, suppressor cell activity dominates.

Human immunodeficiency virus infection related to blood transfusion service.

The prevalence of transmissible viruses, human immunodeficiency (HIV) and hepatitis B (HBV) in blood donors, recipients and blood bank staff in a Calcutta (eastern India) based blood bank and transfusion centre has been studied from 1987-93. HIV seropositivity of blood donors was of recent emergence and was low. Recipients of blood and blood components frequently i.e., haemophilics showed a progressive increase in HIV seropositivity since 1988 whereas in thalassaemics the emergence of HIV seropositivity was noted only in 1992. Blood bank staff were seronegative. HBV which has a similar portal of entry as HIV, had a higher prevalence in blood donors, recipients of blood/components and blood bank staff.

Hepatitis B vaccination and the rate of seroconversion in high risk contacts.

Twenty-seven employees of a blood transfusion centre, Calcutta were vaccinated with hepatitis B vaccine (recombinant DNA technology), 20 micrograms/1 ml intramuscularly on 0, 8, 32 weeks interval. The seroconversion rate at 8, 32, 40 weeks were 29.6%, 55.5% and 100% respectively. The recombinant hepatitis B vaccine is acceptable and safe. The seroconversion rate is comparable to plasma derived hepatitis B vaccine.

Immunosurveillance of transfusion dependent thalassaemia and hepatitis B vaccination.

The study evaluates the probable alteration of the immune system in multitransfused thalassaemics and the modification of their immune response following administration of hepatitis B virus (HBV) vaccine. B-thalassaemics (n = 50) and EB-thalassaemics (n = 30) who received multiple blood transfusion for the chronic anaemic status had significant iron overload. They had high prevalence for hepatitis B carrier state and almost all were exposed to hepatitis B virus during the course of transfusion as shown by the positivity of hepatitis B virus markers. Thalassaemics in presence of iron overload have altered immune status in terms of depressed T-lymphocytes and raised immunoglobulins G and M. However, they showed 100 per cent seroconversion with production of antibody to hepatitis B surface antigen following Hepatitis B vaccination.

Sero-surveillance of transmissible hepatitis B & C viruses in asymptomatic HIV infection in haemophilics.

In a group of 37 haemophilics, 9 (24.3%) were seropositive for human immunodeficiency virus (HIV), while 9 (24.3%) and 10 (27%) were positive for hepatitis B virus (HBV) and hepatitis C virus (HCV) respectively. Haemophilics who were HIV seropositive had higher prevalence of HBV and HCV. Seropositivity for HIV was more in patients with severe haemophilia A who required frequent factor VIII replacement. The need for long term surveillance of voluntary blood donors for transfusion associated viruses like HIV, HBV and HCV, is emphasized.

Prevalence of hepatitis C in transfusion dependent thalassaemics & haemophilics.

Seventy thalassaemics (B = 37, EB = 33) and 20 haemophilics (A = 18, B = 1, C = 1) were tested for antibodies to hepatitis C virus (anti-HCV) and markers for hepatitis B virus (HBV). The seropositivity for anti-HCV in thalassaemics and haemophilics was 14.3 and 25 per cent respectively. The subjects who were sero-positive to anti-HCV had had additional exposure to HBV. Anti-HCV positivity was not related to the age of the subject nor the number of units of blood and blood components transfused. Screening of blood donors for anti-HCV, apart from HBV, may minimise the hazards of post transfusion hepatitis in high risk recipients like transfusion dependent thalassaemics and haemophilics.

Immunologic and survival studies in mice immunised with cryodestroyed ascites fibrosarcoma (AFS) cells.

Adult mice weighing 20 g, divided into 5 groups, were immunised with single and three cycle cryodestroyed ascites fibrosarcoma cells using different modes of immunisation with respect to dose and administration frequency. Survival against subsequent challenge with the same tumour cells and immune response given by leucocyte migration inhibition, were studied in these animals. It appears from the present study that animals with relatively low antigenic load have a significantly (P less than 0.001) high mean survival time and/or survival index compared with controls than those with relatively high antigenic load. Survival in animals immunised with three cycle cryodestroyed tumour cells is significantly (P less than 0.001) higher than that with single cycle even in face of a greater challenging tumour dose with mode of immunisation remaining the same. Preliminary observations on percentage leucocyte migration inhibition showed that there exists no difference in percentage inhibition with either viable or cryodestroyed tumour cell antigens added to migration chamber excepting in animals immunized with three cycle cryodestroyed tumour cells where percentage inhibition was significantly (P less than 0.001) greater with viable than with cryodestroyed tumour cell antigen without altering the percentage inhibition between the two groups. Factors maximising immune response and their modulating effects are discussed.