Prevalence and risk factors for trachoma and ocular Chlamydia trachomatis infection in Niger.

AIMS: To determine the association of personal and household risk factors for trachoma and ocular Chlamydia trachomatis infection in Niger. METHODS: 12 villages were randomly selected. A census of all households was carried out, and 651 children aged 1-5 years were randomly selected and examined. Household and personal characteristics were determined, trachoma was clinically assessed and a swab for ocular C trachomatis infection was taken. RESULTS: The prevalence of trachoma was 43% (95% confidence interval (CI) 39% to 47%) and of infection was 21% (95% CI 18% to 24%). Children aged 3-5 years had a stronger association of clinical signs with infection, compared with those aged 1-2 years. Those with unclean faces were three times more likely to have clinical trachoma or ocular C trachomatis infection, compared with those with clean faces (OR 3.1 (95% CI 1.6 to 6.2) and 3.0 (95% CI 1.4 to 6.3), respectively). 75% of compounds were within 30 min of a water source. Flies on the face were a risk factor for trachoma but not for C trachomatis infection. CONCLUSIONS: The different association of clinical signs with infection in younger versus older children may be an age-dependent difference in the duration of clinical disease. In Niger, unclean faces are a major risk factor for trachoma. The ready availability of water for washing suggests that further research on the effect of a strong health education campaign promoting clean children is warranted in this area.

The hepatocellular thyroid status of uremic rats estimated from the abundances of thyroid hormone-dependent nucleoplasmic proteins.

Although the serum thyroxine (T4) and triiodothyronine (T3) concentrations of uremic rats are commensurate with moderate hypothyroidism, their thyroid status at the tissue level remains controversial. To help establish the hepatocellular thyroid status of uremic rats, a novel tissue marker (nuclear protein abundances) was evaluated in uremic rats (U), hypothyroid rats (H), and hypothyroid uremic rats (HU). Uremia was established by five-sixths nephrectomy. Moderate hypothyroidism was established by partial thyroidectomy or by provision of drinking water supplemented with propylthiouracil and T4. Normal rats (N) and pair-fed, sham-operated rats (1 to 3 weeks after surgery) served as controls. Animals were killed 1 to 5 weeks postoperatively. The following values were obtained 5 weeks after surgery, at which time the total and free serum T4 and T3 levels of the hypothyroid rats (H) were equivalent to those of the uremic rats (U). Total T4 (micrograms/dL +/- 1 SD): N, 5.4 +/- 1.7; H, 2.2 +/- 0.5; U, 1.9 +/- 1.5; HU, 0.5 +/- 0.0. Free T4 (ng/dL +/- 1 SD): N, 535 +/- 165; H, 126 +/- 37; U, 135 +/- 89; HU, 26 +/- 1. Total T3 (ng/dL +/- 1 SD): N, 63 +/- 20; H, 39 +/- 14; U, 38 +/- 18; HU, 13 +/- 4. Free T3 (ng/dL +/- 1 SD): N, 7.83 +/- 3.00; H, 3.87 +/- 1.05; U, 3.47 +/- 1.73; HU, 0.94 +/- 0.47. Hepatocellular thyroid status was estimated from the relative abundances of two nucleoplasmic proteins on polyacrylamide gel electrophoregrams.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue-specific differences in the compartmentalization of rat nuclear triiodothyronine receptors.

In addition to the recognized rat liver nuclear T3 receptor extractable with hypertonic salt, recent studies have described nucleoplasmic receptors extractable with isotonic KCl and salt-resistant receptors localized to the nuclear matrix. A method was developed for the determination of intra-nuclear receptor distribution in small samples of nuclei dispersed within glass wool matrices. After in vitro labelling with 6 nmol/l [125I]T3, dispersed nuclei were sequentially extracted with 0.15 mol/l KCl (yielding nucleoplasmic receptors), 0.4 mol/l KCl. and 2 mol/l KCl (the latter two concentrations yielding hypertonic salt-extractable receptors). The salt-resistant receptors were retained within the glass wool columns. The intra-nuclear distribution of in vivo labelled receptors was very similar to that obtained by in vitro labelling. The equilibrium association constants for L-T3 binding among the receptor pools ranged from 0.6 X 10(9) to 1.0 X 10(9) l/mol. The distribution of total nuclear receptors within each nuclear compartment was (percentage of nucleoplasmic, hypertonic salt-extractable, and salt-resistant receptors): Cerebrum: 23.6, 52.2, 24.2; Liver: 25.2, 57.2, 17.5; Kidney: 45.9, 33.5, 20.6; Testis: 65.5, 14.7, 19.7; and Spleen: 66.7, 18.7, 14.6. The rank order of percentage of hypertonic salt-extractable receptors approximates the rank order of thyroid hormone-responsiveness by traditional criteria. The inverse is true for the percentage of nucleoplasmic receptors. The percentage of salt-resistant receptors was very similar in all of the tissues.

Effect of mass treatment of a human population with ivermectin on transmission of Onchocerca volvulus by Simulium yahense in Liberia, West Africa.

The impact of mass treatment with ivermectin on the intensity of Onchocerca volvulus transmission by the black fly (Simulium yahense) was evaluated on the Liberian Agricultural Company rubber plantation in Liberia, West Africa. The adult pre-treatment prevalence of onchocerciasis was greater than 80%, and the average intensity of infection was 5.35 mf/mg of skin. The drug was administered at 2 annual intervals, reaching 58-60% of the approximately 14,000 people living in 73 camps. Landing/biting catches of black flies made in central and peripheral plantation zones indicated similar fly activity before and after ivermectin treatment (man hr index of 2.1 and 2.4 within the plantation, and 10 and 10.9 outside the plantation, respectively). The number of infected flies with developing larvae (L1, L2, L3 stages) of O. volvulus in treated areas was reduced by 93.4-95%; the number of infective flies with L3 larvae was reduced by 81.7-89.3%. Parasite loads of infected (L1, L2) and infective flies (L3 stages only) outside the plantation also decreased by 86.8% and 80%, respectively. Monthly transmission potential (MTP) showed a similar decrease: from 22.9 to 5.8 (74.6% reduction) in the treated area, and from 210 to 158.8 (24.4% reduction) in untreated areas. Mass treatment with ivermectin efficiently controlled, and at least temporarily interrupted, transmission of Onchocerca volvulus by black fly vectors.

Lack of evidence for aspirin use and prevention of cataracts.

A population-based cross-sectional survey of 838 men aged 30 years and over was conducted to examine the effect of aspirin, and other potential risk factors, on the prevalence of cataracts. Lens opacities were graded on clinical examination for location (cortical, nuclear, and posterior or subcapsular) and severity. The results do not support the claim that large doses of aspirin, or frequent use of aspirin, protects against or retards the growth of lens opacities.