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Biomedical subjects

B Munoz

Publications and source records attributed to B Munoz.

44 records · Page 3Linked to original sources

Cigarette smoking and risk of nuclear cataracts.

The current study was undertaken to assess the relationship of smoking to the risk of lens opacities. The risk was evaluated separately for nuclear and cortical opacities and for both types together. We studied 838 watermen in Maryland by detailed ocular examination for the presence and severity of each cataract type. All subjects were interviewed regarding smoking history, and a cumulative smoking dose was calculated. The results suggest a significantly increased risk of pure nuclear opacities associated with cigarette smoking. The increase in smoking dose was associated with increasing severity of nuclear opacity. The risk of nuclear opacities increased with increasing cigarette dose and decreased if the subject had quit smoking. The effect of smoking was most striking in those less than 80 years old. No increased risk of nuclear opacities was observed with earlier age when smoking started, after adjusting for dose and cessation of smoking. Further investigations are warranted on the biochemical and physical damage to the nucleus of the lens from smoking cigarettes.

Adult↗

Corneal changes associated with chronic UV irradiation.

The association between exposure to UV radiation and corneal disease was investigated in 838 watermen who work on the Chesapeake Bay, Maryland. Individual ocular exposure was calculated by combining a detailed occupational history with laboratory and field measurements. Pterygium was found in 140, climatic droplet keratopathy in 162, and pinguecula in 642. Logistic regression analysis showed that pterygium and climatic droplet keratopathy were significantly associated with a broad band of UV radiation exposure (UV-B, 290 to 320 nm; A1, 320 to 340 nm; and A2, 340 to 400 nm), but the association with pinguecula was weaker. Simple measures such as wearing a hat or spectacles protect the eye and could potentially reduce the amount of pterygium and climatic droplet keratopathy attributable to UV radiation exposure.

Adult↗

Reliability of detection of microfilariae in skin snips in the diagnosis of onchocerciasis.

To quantify the sensitivity of skin snips for the diagnosis of onchocerciasis, data collected over a 2 year period from 261 Liberians, 12-60 years of age, were examined. The overall sensitivity of 6 snips per person was estimated to be 91.6%. When the microfilariae density was greater than or equal to 3.5 microfilariae/mg skin, there were no false negatives. At lower microfilaria densities, the sensitivity declined markedly. Furthermore, it was found that smaller and lighter snips were more likely to be classified as being falsely negative. The load of infection at the community level may be reduced after intervention strategies, such as vector control or community-based chemotherapy. Interpretation of the impact of these programs on the prevalence of infection should take into account the lower sensitivity of the skin snips at lower levels of infection.

Adult↗

Community-based treatment of onchocerciasis with ivermectin: acceptability and early adverse reactions.

A study of community-based treatment of onchocerciasis with ivermectin was undertaken in a rain forest area of Liberia to investigate the possible occurrence of serious adverse effects. The total population was 13,704, the microfilarial load was 5.35 mf/mg skin, and the prevalence of Onchocerca volvulus infection was 50% at 9 years of age and over 80% among those aged 15 years and older. Certain groups (like pregnant women and young children) were excluded from treatment. Out of the 7956 people eligible for treatment, 7699 (97%) accepted the ivermectin. Data on possible adverse reactions were collected by four different methods, including systematic house-by-house follow-up visits three days after treatment, biweekly population surveillance, and monitoring of both mobile clinic records and hospital records. No severe adverse reactions were noted, and no deaths could be related to ivermectin treatment; only 1.3% of the persons treated had a moderate adverse reaction of the Mazzotti type, presumably related to the killing of microfilariae. The study showed good acceptance by the population, and that mass treatment campaigns with ivermectin are feasible.

Adolescent↗

The epidemiology of infection in trachoma.

Specimens for chlamydial isolation culture and direct fluorescent antibody cytology (DFA) were collected from 1671 women and children from a trachoma-endemic area in Central Tanzania. Trachoma was graded using the new World Health Organization grading scheme, and 54% of the children and 9% of the women had inflammatory trachoma (TF or TI). DFA, using the presence of five elementary bodies as the criterion for a positive test, had a sensitivity of 88.0% and a specificity of 87.5% compared to culture and a sensitivity of 54.7% and specificity of 92.8% compared to clinical diagnosis. Altogether, 52.9% of those with trachoma grade TF were positive on either or both culture and DFA versus 77.0% of those with TI. Twenty-nine isolates were serotyped; 18 were serovar A, ten were serovar B, and one was serovar Ba. Positive cultures or DFA were obtained in 6.9% of those graded clinically as not having TF or TI and in a smaller number of those without any perceptible evidence of disease. Conversely, organisms could not be demonstrated in a number of people with severe inflammation (TI) even though some became positive after multiple repeated culture. These two findings of infection without disease and disease without evidence of infection suggest the importance of the immunologic response to infection in determining the clinical status. DFA was found to be an appropriate test for future field studies of trachoma. Further studies of those with disease but without agent and of those with agent but without disease will help understand the dynamics of infection and transmission and the role of the immune response in this important blinding disease.

Adolescent↗

Water availability and trachoma.

As part of an epidemiological survey of risk factors for trachoma in 20 villages in the United Republic of Tanzania, we investigated the relationship of village water pumps, distance to water source, and quantity of household water to the risk of inflammatory trachoma. We also evaluated whether there was an association between the cleanliness of children's faces and these water variables. No association was found between the presence of a village water supply and the prevalence of trachoma. However, the risk of trachoma in the household increased with the distance to a water source--although there was no association with the estimated daily amount of water brought into the house. Likewise, children were more likely to have unclean faces if they lived more than 30 minutes from a water source, but whether they had clean faces was not associated with the daily quantity of water brought into the household. The effect of the distance to water supply on trachoma may well reflect the value placed on water within the family, and this determines the priority for its use for hygiene purposes. The results of the study suggest that changing the access to water per se may be insufficient to alter the prevalence of trachoma without also a concomitant effort to change the perception of how water should be utilized in the home.

Child↗

Evaluation of barriers to surgical compliance in the treatment of trichiasis.

PURPOSE: Eyelid repair surgery can prevent the effects of trichiasis leading to visual loss. Cost, transportation difficulties, and familial responsibilities have been identified as major barriers to surgical compliance. We evaluated whether offering trichiasis surgery in the village was effective in increasing the rate of surgical acceptance and in decreasing perceived barriers to surgery. METHODS: In 1989, 205 women with trichiasis were identified in Central Tanzania and were offered free surgery along with free transport. As of 1991, only 18% of these women had undergone the surgery. We followed-up these women 7 years later after village level surgery was introduced. RESULTS: Since 1991, an additional 12% of the women had undergone eyelid surgery. 44% were conducted in the village. Surgical cases since 1991 reported shorter travel times to the place of surgery, similar post-surgical problems, and fewer days in the hospital. While providing benefits to the patient, increased village eye services did not increase the rate of surgical acceptance. The women who declined surgery did not know surgery in the village was available and the perceived cost and transportation difficulties continued to be barriers. 50% of the non-acceptors stated that there was nothing that would enable them to accept surgical intervention despite the fact that 3/4 of them reported eye symptoms that interfered with their daily activities. CONCLUSIONS: The cost efficacy of village level eye services needs to be evaluated and the awareness of these services increased.

Cost-Benefit Analysis↗