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Biomedical subjects

K S Warren

Publications and source records attributed to K S Warren.

At least 19 recordsLinked to original sources
PubMed1990

An integrated system for the control of the major human helminth parasites.

Disease due to virtually all of the human helminth parasites can be prevented simultaneously by a simple system based on the following premises: 1) helminths do not multiply within their definitive hosts, and their distribution in host populations is overdispersed; 2) disease manifestations occur largely in the small proportion of hosts, often school children, with heavy worm burdens; and 3) a few single-dose, broad-spectrum anthelmintics given in low doses at prolonged intervals can maintain worm burdens below pathogenic levels for almost all of the major human helminth parasites. The three drugs might be albendazole or one of the other benzimidazoles for hookworm, ascaris and trichuris; ivermectin for the filaria, including onchocerca and many other nematodes such as strongyloides; and praziquantel for virtually all trematodes and cestodes. The target group would be school children treated at intervals set to maintain worm burdens below the disease-inducing threshold. It is possible that all three drugs could be administered in low doses simultaneously at yearly intervals. Studies will be necessary to examine drug interactions, development of drug resistance, optimal dosages and timing, and effects on morbidity.

Animals↗
PubMed1988

Hookworm control.

Explore the source record for details and available documents.

Ancylostoma↗
PubMed1988

The evolution of selective primary health care.

This paper traces the evolution of the selective primary health care (SPHC) concept, from its presentation at a meeting in Bellagio, Italy, and its subsequent publication in the New England Journal of Medicine in 1979. It reviews the early debate between those in favor of selectivity and those in favor of comprehensive primary health care (CPHC). While this debate was going on, a breakthrough in terms of implementation came with UNICEF's launching of its Children's Revolution in 1982/83, promoting four specific 'social and scientific advances' for improving the health and nutrition of the world's children. They were growth monitoring, oral rehydration therapy, breastfeeding and immunization. Meanwhile the interest of a number of people for achieving 'Health For All' by targeting for action an essential short list of diseases was the impetus for another conference in 1985, Good Health at Low Cost. Through analysis of the achievements of four societies (Cost Rica, China, Kerala and Sri Lanka) efforts were made to define further a prioritized health development strategy, and a number of measures were identified as helping countries achieve good health. While some have argued that SPCH and CPHC are irreconcilable and diametrically opposed, this paper suggests that both SPCH and CPHC are both acceptable. Technology has its place. The field of view of SPHC has enlarged drastically, from individual diseases to the role of other sectors such as education and agriculture. The concept of SPHC has broadened to accept Rifkin's and Walt's assertion that "developmental processes need further exploration and research strengthening capabilities within countries".(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1986

New scientific opportunities and old obstacles in vaccine development.

The present status of and priorities for vaccine development are described, and the historical conditions under which vaccines have been developed are contrasted with newer technologies for such development. Current programs, the opportunities they present, and the obstacles to their implementation are summarized.

Biotechnology↗
PubMed1979

Selective primary health care: an interim strategy for disease control in developing countries.

Priorities among the infectious diseases affecting the three billion people in the less developed world have been based on prevalence, morbidity, mortality and feasibility of control. With these priorities in mind a program of selective primary health care is compared with other approaches and suggested as the most cost-effective form of medical intervention in the least developed countries. A flexible program delivered by either fixed or mobile units might include measles and diphtheria-pertussis-tetanus vaccination, treatment for febrile malaria and oral rehydration for diarrhea in children, and tetanus toxoid and encouragement of breast feeding in mothers. Other interventions might be added on the basis of regional needs and new developments. For major diseases for which control measures are inadequate, research is an inexpensive approach on the basis of cost per infected person per year.

Animals↗
PubMed1979

Brugia malayi microfilaraemia in mice: a model for the study of the host response to microfilariae.

Microfilariae of Brugia malayi were obtained from the peritoneal cavities of infected gerbils and were then injected intravenously into mice. A sub-periodic, nocturnal microfilaraemia was produced. The level of microfilaraemia was proportional to the number of parasites injected, with approximately 1-3% of microfilariae being found in the peripheral circulation. The duration of microfilaraemia was proportional to the number of parasites injected; it subsided by 30 days after injection of 104 microfilariae but was still present at a low level 120 days after injection of 2 x 105 microfilariae. A transient splenomegaly developed after injection of microfilariae. Histopathological examination revealed large numbers of microfilariae free in the lumens of pulmonary small blood vessels and without any accompanying inflammatory reaction. Lesser numbers of microfilariae were seen in the cardiac blood and hepatic and renal blood vessels for the first few days after injection. There was cellular proliferation in the splenic white pulp and vascular congestion of the red pulp. Microfilariae labelled with 51Cr were injected intravenously; 57% of radioactivity was found in the lungs, 8.5% in the liver and 2.9% in the spleen. Mice developed immediate hypersensitivity reactions to B. malayi antigen by 4 weeks after injection, but Arthus and delayed hypersensitivity reactions were not seen at any time. when mice which had been injected 5 months previously were challenged with a 2nd injection of microfilariae, there was an accelerated clearance of parasites over 2 weeks and a marked peripheral blood eosinophilia developed. In contrast with natural infections, in which the continuous production of microfilariae complicates assessment, this model provides a system in which factors controlling the circulation of microfilariae in the bloodstream can be studied independently.

Animals↗
PubMed1979

Control of schistosomiasis: report of a workshop.

Nineteen scientists, field workers, and representatives of funding agencies active in schistosomiasis research and control met in Bellagio, Italy in October 1977 to attempt to evaluate the effectiveness of current control methods and what might be accomplished with available technology. The deliberations included summaries of knowledge on the biology, transmission, and control of schistosomiasis and assessment of major control programs and methodologies. The groups concluded that in the major endemic areas considerable gains in control of schistosomiasis could be made with current technology. However, maintenance of control in most countries, and establishment of serious control programs in countries in which schistosomiasis is a less severe public health problem, would require development of less expensive modalities which would need little monitoring and possibly have benefits extending beyond schistosomiasis control.

Agriculture↗
PubMed1979

Liver collagen synthesis in schistosomiasis mansoni.

We determined collagen synthetic rates and utilization of key amino acid precursors of collagen in slices of wedge liver biopsy specimens obtained at required surgery from 9 patients with hepatosplenic schistosomiasis and from 4 control patients. The liver specimens from the patients with schistosomiasis showed advanced fibrosis, with histologic evidence of schistosomiasis alone in four, and both schistosomiasis and chronic active hepatitis in five cases. Liver slices were incubated with radioactive proline, arginine and glutamine, using quantitative assay conditions validated earlier for murine schistosomiasis. Collagen peptide synthesis in slices from all nine fibrotic liver specimens was 4- to 25-fold greater than normal and correlated positively with liver collagen content, which was 2- to 5-fold greater than normal. Free proline, an amino acid that may contribute to regulation of collagen peptide synthesis, was increased in six of the nine fibrotic liver specimens, and proline was actively formed from arginine in liver slices from all specimens. These measurements of the initial steps of collagen biosynthesis in fibrotic human liver are quantitatively similar to those previously made of the same processes in experimental animals.

Adolescent↗
PubMed1979

Schistosomiasis haematobia in coast province Kenya. Relationship between egg output and morbidity.

Several studies of schistosomiasis haematobia in Africa have revealed a correlation between intensity of infection as measured by urine egg counts and severity of disease as determined by intravenous pyelography. The present study consisted of a survey of 390 school children in the coastal area of Kenya involving a single egg count, and intravenous pyelograms in a stratified random sample of 69 children; the results showed a greater prevalence of urinary tract disease in those with higher intensities of infection. This survey was then followed by a more detailed study in which nine consecutive daily egg counts were done on 121 children; 17 of these children, subdivided into three groups with different intensities in infection, were given intravenous pyelograms. The results were similar in the 11 children with minimal and moderate counts (averaging, respectively, less than 1 egg and 167 eggs/10 ml urine daily), with approximately 30% having bladder or renal abnormalities. In comparison, all of the six children with heavy counts (averaging 1,288 eggs/10 ml urine daily) had bladder lesions and five of them had renal lesions.

Adolescent↗
PubMed1978

The pathology, pathobiology and pathogenesis of schistosomiasis.

Although the general pathology of schistosomiasis has been well understood for more than 70 years, it is only recently that it has been possible to analyse the disease at the molecular level and to understand the relationship between the number of parasites in an infected individual and the appearance of overt disease.

Animals↗
PubMed1978

Hycanthone dose-response in Schistosoma mansoni infection in Kenya.

The recommended doses of the drugs now used to cure schistosomiasis mansoni may be associated with toxic side-effects. Since Schistosoma mansoni does not multiply in the human host and the disease seems to be closely associated with the intensity of infection, it may not be necessary to use 100% lethal antischistosomal doses, particularly in endemic areas. A dose-response to the antischistosomal drug, hycanthone was established for three different doses in 169 patients with heavy S. mansoni infections in the Machakos district of Kenya. The highest dose used (1.5 mg/kg or half the recommended package-insert dose) resulted in a 96% decrease in egg output (equivalent ot death of the worms); 0.75 mg/kg in an 85% decrease; and 0.375 mg/kg in an 11% decrease one month after treatment. In contrast to the vomiting common with the package-insert dose (3.0 mg/kg), there were no side-effects with any of the lower doses.

Adolescent↗