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Biomedical subjects

J F Walsh

Publications and source records attributed to J F Walsh.

17 recordsLinked to original sources
PubMed1979

Displacements of Simulium damnosum and strategy of control against onchocerciasis.

Regular aerial treatment of 14 000 km of watercourses has achieved and maintained, over an area of 700 000 km2 of West African savannah, a very high degree of control of the larvae of Simulium damnosum sensu stricto and S. sirbanum, the vectors of onchocerciasis in this area. However, particular and relatively restricted parts of this area, mainly in northern Ivory Coast and neighbouring parts of Upper Volta, experience regular and prolonged reinvasions by parous female vectors, which have already taken bloodmeals (and many of them carrying the parasites) and arrive from unknown sources probably hundreds of kilometres away, from directions probably between southwest and north. This reinvasion, now experienced in three successive years, represents the outstanding scientific, epidemiological and logistic problem still facing the WHO Onchocerciasis Control Programme. An outline is presented of the multidisciplinary investigations being undertaken to find a solution.

Africa, Western↗
PubMed1979

Root retention and removable partial denture design.

The position of a retained root for preservation of a ridge requires modification of the design of a distal-extension removable partial denture on the side of the retained root. A model with silicone rubber over the ridges and simulated retained roots was fabricated. A framework with mesial rests, distal proximal plates, and I-bar clasp arms was fitted to it. A pencil lead was attached to the framework to record the arcs of rotation of the I-bar clasp arm. The movements and the fulcrums of the prosthesis were changed by the presence of simulated retained roots posterior to the distal abutment.

Dental Abutments↗
PubMed1979

Entomological aspects of the first five years of the Onchocerciasis Control Programme in the Volta River Basin.

The history and structure of the WHO Onchocerciasis Control Programme in the Volta River Basin are described. An outline of the vector control operations is given, and the techniques and organisation of the entomological evaluation network are described in detail. During the course of the evaluation and related studies undertaken between November 1974 and October 1978 almost 1.2 million S. damnosum females have been taken in over 52,000 man days of catching, and 674,000 flies were dissected. An assessment based on this effort using Annual Biting Rates and Annual Transmission Potentials shows that the transmission of O. volvulus has been reduced to below a defined maximum permissible level over most of the central part of the Programme Area. The difficulties encountered in the remainder, and at certain problem sites are outlined and relevant data given. The benefits to be expected from extending the area further southwards and the possibilities of later reductions in control activity are discussed.

Africa, Western↗
PubMed1979

Studies on the reinvasion of the Onchocerciasis Control Programme in the Volta River Basin by Simulium damnosum s.I. with emphasis on the south-western areas.

The aerial larvicidng operation of the Onchocerciasis Control Programme of the World Health Organization which began in February 1975 resulted in a sharp reduction in Simulium damnosum numbers. However, at the onset of the rainy season the fly population increased in certain areas. Detailed surveys both on the ground and by helicopter did not reveal any significant failures of treatments that could account for the fly densities observed, and it was concluded that the flies must originate from sources outside the controlled zone. This reinvasion proved to be an annual occurrence which has been studied in detail between 1975 and 1978 in the south-western parts of the control zone. The methods used included full day catches by vector collectors carried out every day throughout the season, cytotaxonomic determination of larvae, detailed morphological examination of reared and biting adults and treatment of suspected source rivers with insecticide. The results indicate that the invasion takes place in a SW-NE direction across country for distances of 300 km or more along the track of the monsoon winds. It involves mainly the savanna cytospecies S. damnosum s. str. and S. sirbanum. The invading populations are composed of older parous flies, many of which carry infective 3rd stage larvae indistinguishable from those of Onchocerca volvulus. These females tend to bite close to the rivers and do not disperse as far as normal populations with a higher proportion of younger flies.

Animals↗
PubMed1978

Light trap studies on Simulium damnosum s.l. in Northern Ghana.

The results of light trapping S. damnosum s.l. in northern Ghana during both the wet and dry season are given. It is considered that some flight activity takes place throughtout the night at both seasons. Flies in different physiological states behave differently and gravid females and newly emerged flies appear to be strongly phototactic. There is little evidence to suggest that light trapping is likely to be useful for the capture of blood engorged flies and for the routine monitoring of S. damnosum populations. Further work on the use of light traps in Stimulium studies is required.

Animals↗
PubMed1977

The role of biliary scanning in the investigation of the surgically jaundiced patient.

The diagnostic accuracy of biliary scanning using 99mTc-pyridoxylideneglutamate has been determined in a series of 51 surgically jaundiced patients. This noninvasive technique was found to be safe, reliable and universally applicable in all instances of jaundice, regardless of the serum bilirubin value or prothrombin time. The results were found to compare favorably with those of other investigative procedures. It is suggested that the 99mTc-pyridoxylideneglutamate biliary scan is most advantageously carried out after clinical assessment and full biochemical evaluation of the patient. The scan result will indicate the next logical step in the management of the patient whether it be endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography, biopsy of the liver or laparotomy.

Biliary Tract↗
PubMed1976

Muscle-formed complete mandibular dentures.

A method has been presented whereby a patient's musculature is used to indicate the position of the teeth and to develop the shape and thickness of the denture base. Of 30 patients tested, 28 experienced improved stability of their lower dentures.

Denture Bases↗
PubMed1976

A follow-up study of 300 ex-clients of a drug-free narcotic treatment program in New York City.

This article deals with an attempt at evaluating the success of a drug-free narcotic treatment program in New York City through a follow-up study of 300 ex-clients of the program. Two hundred ex-clients out of the 300 target population were actually interviewed. The number of months the clients had remained in the treatment program was found to be a key factor in the outcome of the program. The length of time in the program was itself highly dependent upon the client's background: the higher the pretreatment pathology the lower the chance of treatment success.

Adolescent↗