Biomedical subjects

A Olsen

Publications and source records attributed to A Olsen.

96 records · Page 6Linked to original sources

PubMedDate not supplied

The impact of iron supplementation on reinfection with intestinal helminths and Schistosoma mansoni in western Kenya.

A randomized, placebo-controlled, double-blind trial was carried out in 1994-96 among 231 children and 181 adults in order to determine the effects of iron on reinfection rates and intensities of hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni. Adults given 60 mg elemental iron twice-weekly for 12 months had significantly lower reinfection rates of A. lumbricoides (16.7% vs 31.9%, P = 0.046), T. trichiura (6.9% vs 20.6%, P = 0.03) and S. mansoni (38.3% vs 61.8%, P = 0.008) compared to adults given placebo. In contrast, adults allocated to iron had a significantly higher reinfection rate of hookworm at the 4-month examination (11.1% vs 0%, P = 0.009), but the difference was not significant at 8- and 12-month follow-up examinations. Iron supplementation had no effect on reinfection intensities in adults. Surprisingly, iron supplementation had no effect on either reinfection rates or intensities in children. Multiple logistic regression analyses controlling for baseline infection status confirmed the effect in adults of iron on A. lumbricoides, T. trichiura and S. mansoni reinfection rates. The effect is suggested to be due to reduced risk behaviour, to improved immune function or to unfavourable host gut conditions caused by an increased oxidative stress. In each case, the lack of effect in children remains to be explained. In contrast, iron supplementation apparently was short-lived in favour of hookworm infection, an effect that needs further clarification. The findings suggest that iron supplementation has a role to play in helminth control programmes and that intraluminal factors may contribute to the regulation of some helminth infections.

Adolescent↗

PubMedDate not supplied

The proportion of helminth infections in a community in western Kenya which would be treated by mass chemotherapy of schoolchildren.

The present study used data from a community-based epidemiological survey of 752 persons in 3 villages in Kisumu District, western Kenya, to examine the proportion of infected persons who would be treated, as well as the effect on helminth egg production, if anthelmintics were provided to schoolchildren. Overall prevalences of hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni infections were 63%, 16%, 24% and 24% respectively, and intensities were low for all infections. Only 79% of the school-aged children were enrolled. For all 4 infections, a school-based programme would treat between 76% and 86% of infected school-age children and would theoretically eliminate between 83% and 92% of the number of eggs excreted by this age group. Of the total population, school-based programmes would treat only between 31% and 50% of the infected persons and eliminate only 15%, 46%, 29% and 27% of the total number of hookworm, Ascaris, Trichuris and S. mansoni eggs excreted, respectively. Provided that school attendance rates were high in the study area, school-based programmes would be efficient in improving the helminth infection status of school-aged children. On the other hand, adults, non-enrolled school-aged children and preschool children not offered treatment represented more than half of the helminth-infected persons and they excreted between half and 85% of the total burden of helminth eggs in the area. Hence, mass chemotherapy of schoolchildren would be less effective in the control of at least hookworm and S. mansoni infections in this specific community. There should therefore be a community-based approach to helminth control in combination with a school-based programme.

Adolescent↗

PubMedDate not supplied

The contribution of hookworm and other parasitic infections to haemoglobin and iron status among children and adults in western Kenya.

A cross-sectional study of 729 children and adults in western Kenya investigated the impact of infection with hookworm, Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni and malaria on iron status. In bivariate analyses, hookworm intensities as low as 300 eggs/g of faeces were negatively related to levels of haemoglobin (Hb) and serum ferritin (SF). Malaria parasitaemia was negatively related to Hb and positively related to SF, while S. mansoni intensities were negatively related to SF. Multivariate regression analysis was done to identify predictors of Hb and SF levels. In children, age (in years) was the only predictor for Hb (B = 1.7 g/L) and only malaria parasitaemia (negative, light, moderate, heavy) was retained in the model for log10 SF (B = 0.097 microgram/L). In adults, hookworm infection and malaria parasitaemia together with age, sex, pregnancy, SF levels < 12 micrograms/L and elevated body temperature were significant predictors of low Hb. The regression coefficient for hookworm egg count (for increments of 100 eggs/g) was -1.3 g/L. Significant interactions between sex and age and between sex and malaria parasitaemia were revealed. Age and malaria parasitaemia were significant predictors only among females, with a regression coefficient for malaria parasitaemia of -6.9 g/L. The regression coefficient for hookworm did not change when SF < 12 micrograms/L was taken out of the model, indicating that the effect of hookworm cannot be explained by low iron stores alone. Using SF as the dependent variable, hookworm and S. mansoni intensities together with age and sex were retained in the model. The regression coefficients for hookworm egg count (increments of 100 eggs/g) and S. mansoni egg count (increments of 10 eggs/g) were -0.011 microgram/L and -0.012 microgram/L, respectively. Iron deficiency was a problem in this population and hookworm infections contributed significantly to this situation.

Adolescent↗

PubMedDate not supplied

[8-oxoguanosine as a marker of neoplastic process in brain].

Reactive oxygen species are toxic and cancerogenic factors to living organisms. They are suggested to cause DNA damage (modification) that triggers cancer development. It seems that oxidative damage product 8-oxo-deoxyguanosine (8-oxo-dG) which induces transversion of G to T could be a good chemical marker for cancerogenesis. The aim of our studies was to use 8-oxo-dG as a probe for brain tumour in 17 patients operated on for intracranial neoplasm. Among the patients there were 7 female and 11 male aged from 14 to 60 year. Mean age was 42.88 +/- 16.14 yrs. Several types of tumours were selected histopathologically: from neuroepithelial tissue--6 cases, meningeomas--4, metastases--3, lymphomas--2, neurinoma--1 and chondrosarcoma--1. The tumour tissue was collected from removed material and stored at -20 degrees C. DNA from the neoplastic tissues was isolated by salt method. After hydrolysis of DNA with nuclease P1 and dephosphorylation with bacterial alkaline phosphatase, the mixture of nucleosides was analysed by liquid chromatography method connected with electrochemical detector (HPLC-ECD) working at potential 400 mV. We found higher level of 8-oxo-dG in DNA of patients with malignant tumour (glioblastoma). However, at the present stage of these studies there was no proportional correlation between the level of 8-oxo-dG in DNA in tumour tissue and its malignancy.

Adjuvants, Immunologic↗

PubMedDate not supplied

Renal medullary cystic disease. Findings at urography and ultrasonography.

Medullary cystic disease (MCD) is an uncommon renal disease with adult onset and autosomal inheritance, eventually progressing to terminal renal failure. It may be difficult to identify because of insufficient diagnostic tools. At urography, the same ring-shaped accumulation of contrast medium at the corticomedullary junction was observed in two patients (mother and son) suffering from MCD. To our knowledge this observation has not been reported before.

Adult↗

PubMedDate not supplied

Evaluating a computer-based experiential learning simulation: a case study using criterion-referenced testing.

A case study of a computer-based experiential learning program involving the use of criterion-referenced testing as a quantitative evaluation tool is described. The simulation was designed to introduce nurses to basic computer operations. One hundred and thirty-eight nurses participated in the evaluation using a specially prepared version of the program that recorded the time required to perform actions, the number of unsuccessful attempts to complete instructions, and the number of correct responses to specific questions. The ability of the nurses to "drag and drop" increased significantly from less than 20% to more than 90% (p < .05, Student's t-test). Their knowledge of the definitions of four computer-related terms (i.e., trackball, desktop, window, and icon) increased significantly (from 65% to 80%, p < .1). In subjective evaluations, 82% of respondents reported that they enjoyed the lesson and 89% wanted more computer-based instructional units to be developed. Use of criterion-referenced testing helped to shed new light on the utility of such computer aided instructional systems.

Academic Medical Centers↗