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Biomedical subjects

H Dixon

Publications and source records attributed to H Dixon.

53 records · Page 3Linked to original sources
PubMed1976

The first international standard for human urinary FSH and for human urinary LH (ICSH), for bioassay.

This paper describes the preparation and nature of the First International Standard for Human Urinary Follicle Stimulating Hormone and for Human Urinary Luteinizing Hormone, for Bioassay, and of two batches of working standard which were prepared from the same material. A collaborative study of these materials was carried out by six laboratories in six different countries. The FSH and LH activities of the Standard were assayed in terms of those of the Second International Reference Preparation of Human Menopausal Gonadotrophins, Urinary, for Bioassay, which it replaces. The results from 20 valid FSH assays and 30 valid LH assays (using four different methods) obtained in this way gave a weighted combined potency estimate for FSH of 53.7 IU, with 95 % fiducial limits of 47.2-61.1 IU, and for LH of 46.2 IU, with 95 % fiducial limits of 43.3-49.3 IU. Accelerated degradation studies of the Standard stored at elevated temperatures suggested that the stability of both FSH and LH activities under normal storage conditions would be satisfactory. The FSH and LH activities of the two batches of working standard (WS-A and WS-B) were compared with those of the Standard and were not found to differ significantly, except for the LH activity of WS-B which appeared to be slightly higher than that of the Standard. Accelerated degradation studies did not show any significant differences in stability between the Standard and batches of working standards. On the basis of these results the Standard has been established by WHO and allocated a potency for FSH of 54 IU per ampoule and for LH 46 IU per ampoule. The International Units for FSH, Human Urinary, for Bioassay and for LH (ICSH), Human Urinary, for Bioassay are thus defined as the activities contained in 0.1138 mg and 0.13369 mg of the International Standard, respectively.

Biological Assay↗
PubMed1969

Effect of dihydrostreptomycin on protein synthesis in whole cells and in cell-free extracts of a streptomycin-dependent strain of Escherichia coli B.

The effect of dihydrostreptomycin on the incorporation of amino acids into protein in antibiotic-deprived cells of a streptomycin-dependent strain of Escherichia coli B has been compared with its effect on protein synthesis in extracts from cells of the same strain. Stimulation of phenylalanine incorporation into protein in whole cells occurred within 5 min of addition of dihydrostreptomycin to a deprived culture and was maximal at an antibiotic concentration of 20 mug/ml. Stimulation of protein synthesis in cell-free extracts from antibiotic-deprived cells was maximal at a dihydrostreptomycin concentration of 10 mug/ml in systems programmed with f2-ribonucleic acid and poly AGU, whereas extracts from cells grown on nonlimiting concentrations of dihydrostreptomycin were unaffected by the addition of antibiotic. These results indicate that protein synthesis is an antibiotic-requiring process in streptomycin-dependent E. coli B.

Amino Acids↗
PubMedDate not supplied

Public reaction to Victoria's "2 Fruit 'n' 5 Veg Every Day" campaign and reported consumption of fruit and vegetables.

BACKGROUND: The Victorian "2 Fruit 'n' 5 Veg Every Day" campaign was aimed at increasing awareness of the need to eat more fruit and vegetables and encouraging increased consumption of these foods in the Australian state of Victoria. The demand-side component of the campaign, which had television advertising as a centerpiece, ran from 1992 to 1995. METHODS: Annual postcampaign telephone surveys of approximately 500 Victorians ages 20 and over were conducted with the aim of examining public awareness of the campaign, beliefs about desirable eating habits for fruit and vegetables, and reported consumption of these foods. RESULTS: Over the years, patterns in the level of public awareness, reported consumption, and beliefs about appropriate levels of consumption have tended to parallel changes in the level of mass media investment. During the campaign's most intense period of promotional activity, significant increases in all of these variables occurred. CONCLUSIONS: The results suggest that significant achievements can be made with relatively small-budget mass media promotion of dietary recommendations, especially when part of a more comprehensive program. However, campaigns may need to be adequately resourced for several years if sustained change is to be achieved.

Adult↗
PubMedDate not supplied

Control of morbidity due to Schistosoma haematobium on Pemba island; selective population chemotherapy of schoolchildren with haematuria to identify high-risk localities.

In Pemba, Tanzania, 2 sequential surveys were made of the prevalence of haematuria in children (aged 5-19 years) in 52 schools, using direct observation of gross haematuria (bloody urine) and chemical reagent strips as indicators of Schistosoma haematobium infection. 24,462 children were examined in the first survey and 25,575 in the second, 6 months later. The prevalence of gross haematuria was initially 15.8% (3876 cases); 6 months later, after a single dose of praziquantel (40 mg/kg), it was only 2.4% (613 cases), a reduction of 84.9%. The total number of cases of haematuria (gross or otherwise) dropped similarly, from 13,920 (54%) to 6638 (26%), a 52.2% reduction. In towns the degree of reduction was positively correlated with the standard of water supply and sanitation available, and the initial prevalence of gross and total haematuria in schools was positively correlated with the prevalence 6 months later. The cost per person reduced from US$ 0.83 in the first survey to US$ 0.48 in the second (excluding field staff wages paid in local currency), the reduction being due to the reduced number of positive persons. This study has demonstrated the feasibility of using indirect techniques on a large scale for the diagnosis of S. haematobium infection to identify schoolchildren requiring treatment, and to monitor its impact on clinical morbidity in a highly endemic area.

Adolescent↗