Showing papers by "World Health Organization published in 1987"

Tumor necrosis factor (cachectin) as an essential mediator in murine cerebral malaria.

Abstract: Tumor necrosis factor, or cachectin (TNF-alpha), a protein with a wide range of biological activities, is produced mainly by macrophages and may be important in inflammatory processes. The role of TNF-alpha in the pathogenesis of cerebral malaria was investigated in a murine model. Most CBA mice infected with Plasmodium berghei anka die between days 6 and 14 with acute neurological manifestations unrelated to the level of parasitemia, whereas mice of some other strains have malaria of the same severity that ends in death after 3 to 4 weeks without neurological manifestations. The activity of serum TNF-alpha was considerably increased in CBA/Ca mice with cerebral malaria but not in Plasmodium berghei-infected mice that did not develop this complication. One injection of rabbit antibody to TNF-alpha on day 4 or 7 fully protected infected mice from cerebral malaria without modifying the parasitemia, whereas immunoglobulins from normal rabbit had no effect. In mice with cerebral malaria, the cerebral vessels showed focal accumulations of packed macrophages often containing infected erythrocytes; this lesion was not seen in mice treated with antibody to TNF-alpha or in untreated mice without cerebral malaria. These findings indicate that TNF-alpha has an important role in the pathogenesis of cerebral malaria in this murine model and suggest that local accumulation and activation of macrophages may lead to the predominance of lesions in the central nervous system.

A simple system for the assessment of trachoma and its complications

Abstract: A simple grading system for trachoma, based on the presence or absence of five selected "key" signs, has been developed. The method was tested in the field and showed good observer agreement, the most critical point being the identification of severe cases of the disease. It is expected that the system will facilitate the assessment of trachoma and its complications by non-specialist health personnel working at the community level.

Intrauterine growth and gestational duration determinants.

Abstract: Despite the general recognition that low birth weight can be caused by many factors, confusion and controversy remain about which factors have independent causal effects, as well as the quantitative importance of those effects. Previous research findings have often been conflicting because of a failure to distinguish intrauterine growth retardation from prematurity, differences in focus (means v rates), inadequate control for confounding variables, and insufficient statistical power. This review of the English and French language medical literature published between 1970 and 1984 is based on a critical assessment and meta-analysis of 895 studies concerning 43 potential determinants of intrauterine growth or gestational duration. Based on methodologic standards established a priori for each candidate determinant, the best studies were used to assess the existence and magnitude of an independent causal effect on birth weight, gestational age, prematurity, and intrauterine growth retardation. Factors with well-established direct causal impacts are identified, and their relative importance is indicated for "typical" developing and developed country settings. Modifiable factors with large effects are targeted for public health intervention in the two settings. Finally, factors of potential quantitative importance, but for which data are either unavailable or inconclusive, are highlighted as priorities for future research.

Prevalence of the Epilepsies in Nigerian Africans: A Community‐Based Study

Abstract: A door-to-door survey to detect commonly occurring neurologic diseases was carried out in Igbo-Ora, a large Nigerian town with a population of approximately 20,000. Effective health care facilities have been operating in the community since 1963. Primary health care workers and nondoctor personnel administered a complete census, a screening questionnaire, and a simple screening neurologic examination. The pretested screening questionnaire had been shown in a pilot study to have a sensitivity of 95% for identifying those with epilepsy. Individuals positive on the screening phase of the survey were evaluated by neurologists and neurosurgeons, who used well-defined criteria to make the diagnosis. There were 101 (48 males and 53 females) who suffered from active epilepsy (5.3 cases/1,000) on prevalence day. The highest age-specific prevalence ratios occurred in those below age 20. The most common of the identifiable seizure types was complex partial seizures (52 cases). The prevalence ratio of epilepsy in this Nigerian town (with an effective health care system) is similar to that reported in some developed countries and several times lower than figures derived from studies in developing countries. These data suggest that an improved health care system would probably reduce the prevalence and burden of epilepsy in developing countries.

Expressed emotion and schizophrenia in north India. II. Distribution of expressed emotion components among relatives of schizophrenic patients in Aarhus and Chandigarh.

Abstract: We measured the components of expressed emotion among two samples of relatives of first-contact patients from Aarhus (Denmark) and Chandigarh (India). The Danes were very similar in most respects to samples of British relatives, whereas the Indian relatives expressed significantly fewer critical comments, fewer positive remarks, and less over-involvement. Within the Chandigarh sample, city-dwellers were significantly more expressive than villagers of all EE components except over-involvement.

Q fever in Europe: current aspects of aetiology, epidemiology, human infection, diagnosis and therapy.

Abstract: Il s'agit d'une zoonose. Elle est en general asymptomatique bien que des decouvertes nouvelles aussi bien chez l'homme que chez l'animal mettent en evidence des syndromes cliniques associes en particulier des maladies chroniques graves

Evaluation of the genetic and embryotoxic effects of bis(tri-n-butyltin)oxide (TBTO), a broad-spectrum pesticide, in multiple in vivo and in vitro short-term tests

Abstract: The genetic and embryotoxic effects of bis(tri-n-butyltin)oxide (TBTO) were evaluated in multiple in vivo and in vitro short-term tests preparatory to its potential wide use as a molluscicide in control of schistosomiasis. When tested in the rec assay in Bacillus subtilis, TBTO was not mutagenic and it did not induce reverse mutations in Klebsiella pneumoniae. Neither in the presence nor in the absecne of rat liver activation system did TBTO produce point mutations in Salmonella typhimurium strains TA1530, TA1535, TA1538, TA97, TA98 or TA100. TBTO was matagenic in strain TA100 in a fluctuation test, but only in the presence of rat liver S9 (Aroclor-induced). TBTO did not induce gene mutations in the yeast Schizosaccharomyces pombe, mitotic gene conversions in the yeast Saccharomyces cerevisiae, nor sister-chromatid exchange in Chinese hamster ovary cells in the presence or absence of rat or mouse liver S9. In the latter cells, structural chromosomal aberrations, endoreduplicated and polyploid cells were induced. TBTO did not induce gene mutations in V79 Chinese hamster cells (to 8-azaguanine-, ouabain- or 6-thioguanine-resistance) in the presence of a rat liver postmitochondrial fraction or in cell (hamster embryo cells and human and mouse epidermal keratinocyte)-mediated assays. In mouse lymphoma cells, TBTO did not induce 6-thioguanine- or BUdR-resistant mutations. As many tumour promoters inhibit metabolic cooperation between V79 Chinese hamster 6-thioguanine-resistant/-sensitive cells, TBTO was tested but showed no such activity. TBTO was examined for the induction of recessive lethal mutations in adult Berlin K male Drosophila melanogaster, either by feeding or by injection. Doses of 0.37 or 0.74 mM did not increase the number of X-linked recessive lethal mutations. An increased number of micronuclei was observed in the polychromatic erythrocytes of male BALB/c mice 48 h after a single oral dose of TBTO (60 mg/kg bw), while a lower dose (30 mg/kg bw) was ineffective. Neither of the two doses had induced micronuclei 30 h after treatment. The reproductive toxicity of TBTO was studied in NMRI mice. In a 10-day toxicity study, the LD50 and LD10 were 74 and 34 mg/kg bw, respectively. An increased frequency of cleft palates was seen in the fetuses of mice (compared with controls, 0.7%) treated orally during pregnancy with 11.7 mg/kg TBTO (7%), 23.4 mg/kg (24%) or 35 mg/kg (48%).(ABSTRACT TRUNCATED AT 400 WORDS)

Relationship of Plasma Level of Vitamin C to Mortality from Ischemic Heart Disease

Abstract: The present epidemiological data support and extend previous evidence in men and animals. Thus, a poor plasma status of vitamin C (less than 23 microM = 0.4 mg/dl) and/or of cholesterol-standardized vitamin E (less than 20-21.5 microM = 9 mg/l) occurs in westernized countries with an increased risk of IHD. A poor status in the major essential antioxidants may be a hitherto underrated, at least permissive, risk factor of IHD that could, at least in some European countries, substantially complement the previously established risk factors such as hypercholesterolemia.

Stochastic model for interhuman spread of monreypox

Abstract: With the eradication of smallpox, systematic routine vaccination with vaccinia has ceased and an increasing proportion of the human population in tropical rain forest areas of central and western Africa lacks vaccinia-derived immunity to monkeypox virus. This raises the question of the ability of monkeypox virus to establish and maintain itself in an unvaccinated population through continuous man-to-man transmission. A computerized stochastic model of Monte Carlo type was constructed to assess this potential risk. Simulated series were repeated 100 times to obtain distributions of predicted outcomes for decreasing levels of vaccination coverage (70 per cent, 50 per cent, and 0 per cent). The results revealed a substantial increase in new secondary cases in the total absence of vaccinia-induced immunity. Nevertheless, none of the simulated series did lead to an "explosive" epidemic. The model clearly indicated diminishing numbers of cases in successive generations and eventual cessation of transmission. Therefore, it appears highly improbable that the virus could maintain itself permanently in communities by interhuman transmission. After the eradication of smallpox, human monkeypox constitutes the most important orthopoxvirus infection in man, but analysis of information collected up to this time suggests that it does not represent currently a serious public health problem or a challenge to the achieved eradication of smallpox.

Antibodies to the repetitive epitope of Plasmodium falciparum circumsporozoite protein in a rural Tanzanian community: a longitudinal study of 132 children.

Abstract: An ELISA employing a novel synthetic peptide consisting of 40 (Asn-Ala-Asn-Pro) repeats of Plasmodium falciparum circumsporozoite protein, (NANP)40, was used to detect antibodies against P. falciparum circumsporozoite protein in 132 children, 1 month to 15 years old, from a rural community (Kikwawila village) of Tanzania, a region where malaria is hyperendemic. The children were surveyed comprehensively over 3 consecutive years for clinical, parasitological, and serological parameters. Entomological data were also gathered for selected households in this village. The following results were obtained: anti-(NANP)40 antibodies increased as a function of age; the majority of children over 10 years showed a stable positivity for such antibodies during the longitudinal study; a negative correlation was observed between the levels of anti-sporozoite antibodies and both spleen enlargement and the presence of parasites in thick smears; no relationship was found between anti-(NANP)40 antibodies and asexual blood stage antibodies; children living in two representative households with comparable indoor resting mosquito densities showed markedly different frequencies of anti-(NANP)40 antibodies, in spite of comparable clinical, parasitological, and serological parameters. Thus, in addition to the exposure to infectious mosquito bites, other (e.g., genetic) factors, may play a role in the ability of certain individuals to mount an antibody response against this immunodominant repetitive epitope. The results presented in this paper confirm that the (NANP)40-ELISA represents a simple, reliable means for the detection of anti-(NANP)40 circumsporozoite protein antibodies and suggest that such antibodies may contribute to the immune protection against malaria in humans.

Cross-reactions between pneumococci and other streptococci due to C polysaccharide and F antigen.

Abstract: By serological methods, all 83 known types of Streptococcus pneumoniae could be shown to possess C polysaccharide and F antigen. Cross-reactions due to these two antigens between pneumococci and a broad range of most other commonly encountered streptococci were examined. The presence of an antigen closely similar or identical to pneumococcal C polysaccharide was demonstrated in some strains of Streptococcus mitior. Therefore, we conclude that pneumococci cannot be identified serologically from mixed samples without culture. Streptococcal group C antiserum was found to cross-react with pneumococcal F antigen. Images

Epstein-Barr virus mediates a switch in responsiveness to transforming growth factor, type beta, in cells of the B cell lineage.

Abstract: The functional performance of the transforming growth factor beta (TGF beta), appears to depend on the target cell phenotype as well as in vitro culture conditions. We show here that Epstein-Barr virus (EBV)-infection may induce a change in responsiveness to TGF beta, since TGF beta inhibits traverse of the cell cycle of activated normal human B cells, but promotes cell proliferation of EBV-positive Burkitt's lymphoma cell lines as well as EBV-infected B cells. We present evidence that the switch in the responsiveness to TGF beta is mediated by EBV infection, irrespective of the proliferative status of target cells, and thus may contribute to the initiation as well as the maintenance of certain B cell neoplasias.

Treatment of human late stage gambiense trypanosomiasis with alpha-difluoromethylornithine (eflornithine): efficacy and tolerance in 14 cases in Côte d'Ivoire.

Abstract: alpha-Difluoromethylornithine (DFMO; eflornithine), an inhibitor of polyamine biosynthesis, was used to treat 14 patients with late stage gambiense sleeping sickness, 12 cases having been previously treated with and considered refractory to melarsoprol. alpha-Difluoromethylornithine was administered intravenously at a dose of 400 mg/kg/day for 14 days followed by oral treatment, 300 mg/kg/day, for 21-28 days. In all patients treatment was associated with rapid disappearance of trypanosomes from body fluids (in several cases within 24 hr) and decreased cerebrospinal fluid white blood cell counts. In all but one patient, who died of a pulmonary infection during treatment, alpha-difluoromethylornithine produced a dramatic reversal of clinical signs and symptoms of the disease. Determination of drug concentrations in serum and cerebrospinal fluid of 5 patients demonstrated that alpha-difluoromethylornithine diffuses into the central nervous system with cerebrospinal fluid levels representing up to 51% of corresponding serum concentrations. Diarrhea, abdominal pain, and anemia were the most frequent side effects associated with therapy, but were reversible and did not necessitate discontinuation of treatment. Four patients have been followed for more than 2 years post-treatment without evidence of relapse.

Multicultural studies and the nature schizophrenia: a review.

Abstract: 0141-0768/87/ 030162.06/$02.00/0 Q1987 The Royal Society of Medicine Schizophrenia, a condition of obscure origins and no established aetiology, pathogenesis and pathology, continues to be a major focus of psychiatric research and public health concern. The diagnosis of schizophrenia accounts today for well over 50% of the 'long-stay' psychiatric hospital populations in many industrialized countries, and extrapolations from the current incidence rates and demographic trends lead to predictions of further increases of the total number of cases by the end of the century, especially in Third World countries1.

On the assessment of maternal mortality.

Abstract: Well over 1/2 the maternal deaths in the world occur in 3 countries in southern Asia: India Pakistan and Bangladesh. In general the incidence of maternal death correlates with 2 factors: a high risk of dying during or just after pregnancy due to sepsis inadequate facilities for dealing with complicated births or other health problems such as exacerbation of existing disease poor nutrition overwork and/or closely spaced pregnancies; and a high fertility rate. This report outlines methods for measuring maternal mortality and presents data for developing nations in each continent comparing it to developed nations and determing its contribution to overall mortality. The risk of dying as a result of a given pregnancy in a developed nation is at least 100-fold smaller than that in the poorest countries in Africa and Asia. Estimated mortality due to pregnancy is 460000 more women in the undeveloped nations compared to the developed nations.

The future of sex mortality differentials in industrialized countries: A structural hypothesis

Abstract: This paper advances the hypothesis that the future of sex mortality differentials in industrialized countries may depend on the future mortality rates of blue collar men. Data are presented to support the argument that mortality rates from ischemic heart disease for this population subgroup play a significant role in current differentials and, furthermore, that sexsocial class-mortality differentials correspond to social structural differences in protection against and/or exposure to health risks. Research and policy implications of this argument are addressed briefly.

Management of insecticide resistance in control of the Simulium damnosum complex by the Onchocerciasis Control Programme, West Africa: potential use of negative correlation between organophosphate resistance and pyrethroid susceptibility.

Abstract: . 1. Resistance of some populations of the Simulium damnosum complex to temephos (100-fold at the LC50 level), with degrees of cross-resistance to chlorphoxim (14-fold) and other organophosphate insecticides, follows intensive larvicidal control of S.damnosum s.l. in West African river systems since 1975 by the WHO Onchocerciasis Control Programme. 2. Larvae of at least three sibling species of the S.damnosum complex have become organophosphate-resistant: these are the forest species S.sanctipauli Vajime & Dunbar and the savanna species S.sirbanum V. & D. and S. damnosum Theobald sensu stricto. 3. Organophosphate-resistant S.damnosum s.l. larvae show increased susceptibility to some organochlorine and pyrethroid insecticides, especially to permethrin (up to 11-fold) and OMS 3002 (up to 17-fold), as compared with organophosphate-susceptible populations. 4. This differential susceptibility is reflected by increased pyrethroid efficacy in operational use for river treatments against organophosphate-resistant field populations of S.damnosum s.l. larvae. Treatment of 100 km of the lower Bandama River in 1985 showed that permethrin at the highly selective dosage of 10 min exposure to 0.01 mg/1 caused reversion towards organophosphate-susceptibility of the target population of S.sanctipauli. This effect was less pronounced when the Comoe River was treated at the lower dosage of 0.005 mg/1 for 10 min. 5. To overcome temephos-resistance, it is proposed that the most rational usage of currently available larvicides would involve the following annual sequence of treatments: Bacillus thuringiensis serotype H-14 when river discharge is below 75 m3/s; chlorphoxim for about eight weekly treatment cycles after river discharge rises; permethrin (or alternative pyrethroid) for up to six treatment cycles - this should eliminate any incipient selection for chlorphoxim-resistance; resume chlorphoxim (or perhaps carbosulfan) treatments until river discharge falls below 75 m3/s permitting resumed use of B.t. H-14.