Biological standardization of pollen allergens from India.

Standardization of allergens are achieved by in vitro and in vivo methods. Some of the allergens from Western countries are standardized using biological potency of the extracts but no attempt has been made till now to standardize any of the pollen extracts from India based on biological units. Therefore, we have attempted to standardize two important pollen allergens Ricinus communis and Holoptelea integrifolia by biological methods. Broadly the methods adopted by Dreborg and Grimmer (1983) was followed. Skin prick tests were carried out with the extracts of R. communis and H. integrifolia on 15 allergic patients in five three fold log dilutions starting with 1:10, in 50% glycerinated buffer. Glycerinated buffer (50%) and histamine dihydrochloride (1 mg/ml) were used as negative and positive controls, respectively. The mean wheal diameter obtained with different concentrations showed a gradual systematic fall with increase in dilution. The mean relative diameter (% of histamine reaction) varied from 124.1 +/- 8.9 to 33.7 +/- 6.1 and 78.9 +/- 5.5 to 21.4 +/- 3.8 with the highest and lowest concentrations of R. communis and H. integrifolia pollen antigens, respectively. The histamine equivalent concentration of antigen 1,000 Biological Units (BU) obtained for crude pollen extracts of R. communis and H. integrifolia was 1:17 and 1:22 respectively.

Prevalence of high risk children under five--a study in rural Delhi.

678 under five children were surveyed in village Shahbad Mohammadpur, Delhi. Two weeks morbidity was also recorded. 47.9 per cent children had one or more risk factors studied. Significantly more female children (54.1 per cent) were at risk than male children (43.3 per cent). 433 risk factors were observed in 325 at risk children. Majority of them had one or two risk factors. Birth interval less than two years and malnutrition were most frequent risk factors. At risk children suffered significantly more than not at risk (21.2 per cent vs 14.4 per cent). The results confirmed the validity of the risk factors considered for the study.