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Biomedical subjects

R Wyatt

Publications and source records attributed to R Wyatt.

At least 73 records · Page 4Linked to original sources
PubMed1991

Postinjection L-phenylalanine increases basal ganglia contrast in PET scans of 6-18F-DOPA.

The sensitivity of 18F-DOPA positron emission tomography for imaging presynaptic dopamine systems is limited by the amount of specific-to-nonspecific accumulation of radioactivity in brain. In rhesus monkeys, we have been able to increase this ratio by taking advantage of the lag time between 18F-DOPA injection and the formation of its main metabolite, the amino acid 18F-fluoromethoxydopa, the entrance of which into brain is responsible for most of the brain's nonspecific radioactivity. By infusing an unlabeled amino acid, L-phenylalanine, starting 15 min after 18F-DOPA administration, we preferentially blocked the accumulation of 18F-fluoromethoxydopa by preventing its entrance into brain through competition at the large neutral amino acid transport system of the blood-brain barrier. This method appears as reliable as the original and more sensitive, as demonstrated by the comparison of normal and MPTP-treated animals under both conditions.

Animals↗
PubMed1990

Training assistants in cleft palate speech therapy in the developing world: a report.

This paper describes the training, which took place in Sri Lanka, of five speech therapy assistants in cleft palate speech therapy. The context in which this training occurred is described. The original aims of the training and the criteria drawn up for the selection of the assistants are contrasted with the modifications required to these, once the British therapists started working in Sri Lanka. Information is given on the training objectives, syllabus, curriculum, and methods of evaluation of the assistants' progress. The achievements of the assistants are described. Factors relating to the difficulties and ease with which the assistants were trained are highlighted. The paper concludes with a discussion of the cultural, political, and clinical problems encountered in this type of training, and highlights the special difficulties encountered in the training of assistants in the field of speech therapy in developing countries.

Allied Health Personnel↗
PubMed1990

Training counterparts in cleft palate speech therapy in the less developed world: an extended report.

This paper describes the training of five counterparts in cleft palate speech therapy which took place in Sri Lanka. The context in which this training occurred is described. The original aims of the training, and criteria drawn up for the selection of the counterparts, are contrasted with the modifications required to these once the British therapists started working in Sri Lanka. Information is given on the training objectives, syllabus, curriculum and methods of evaluation of the counterparts' progress. The achievements of the counterparts are described, and factors relating to the difficulties and ease with which the counterparts were trained are discussed. The paper concludes with a discussion of the cultural, political and clinical problems encountered in this type of training, and highlights the special difficulties encountered in the training of counterparts in the field of speech therapy in less developed countries.

Allied Health Personnel↗
PubMed1989

Laser Doppler flowmetry for bone blood flow measurements: helium-neon laser light attenuation and depth of perfusion assessment.

Laser Doppler flowmetry (LDF) has been successfully used in clinical and experimental settings to evaluate bone perfusion but unanswered questions regarding its capabilities and limitations still remain. This study was undertaken to determine absorption of He-Ne laser light (632.8 nm) and maximum depth for flow assessment (threshold thickness) under optimal conditions in bone. Light transmittance in bovine bone samples of femora and tibia was measured after each step of grinding and depth of penetration calculated. The threshold thickness was obtained by placing the same samples in a flow chamber where a solution of 2% latex circulated beneath; flow was detected by a laser Doppler probe resting on top of the sample. The results showed a significantly higher depth of penetration for trabecular than for cortical bone. A regression analysis showed a high correlation between the inorganic fraction of the bone and the depth of penetration. The maximum depth at which the laser Doppler probe can evaluate flow in bone conditions was found to be 2.9 +/- 0.2 mm in cortical bone, 3.5 +/- 0.3 mm in bone covered by 1 mm cartilage and 3.5 +/- 0.2 mm in trabecular bone. The study showed the limitations of LDF in bone and their correlations to various bone properties.

Animals↗
PubMed1988

Allopolyploidy in bryophytes: Multiple origins of Plagiomnium medium.

Bryophytes are thought to be unique among land plants in lacking the important evolutionary process of allopolyploidy, which involves interspecific hybridization and chromosome doubling. Electrophoretic data show, however, that the polyploid moss Plagiomnium medium is an allopolyploid derivative of Plagiomnium ellipticum and Plagiomnium insigne, that P. medium has originated more than once from these progenitors, and that cross-fertilization results in interlocus genetic recombination. Evidence from restriction fragment length polymorphisms in chloroplast DNA implicates P. insigne as the female parent in interspecific hybridizations with P. ellipticum. Contrary to prevailing views, it appears that those evolutionary processes responsible for genetic differentiation and speciation in other land plants occur in the bryophytes as well.

Journal Article↗
PubMed1987

Immunohistochemical studies of blood group substance H in colorectal tumors using a monoclonal antibody.

With the use of a murine monoclonal antibody with specificity for human blood group substance H, the distribution of this antigen on colorectal carcinomas and adenomatous polyps has been studied by immunohistochemistry. All of the 20 carcinomas studied were found to express H substance regardless of their location in the colon, their pathologic grade, or their clinical stage. Adenomas were variably positive for H substance, and expression of the antigen appeared to correlate with the degree of dysplasia seen on microscopic examination. Normal colonic mucosa, nonadenomatous polyps, and nonepithelial colonic neoplasms studied failed to express H substance. The results suggest that detection of H substance expression may be useful in the diagnosis of colonic malignancies and dysplastic premalignant lesions.

Adenocarcinoma↗
PubMed1985

Douglas House: a new type of hostel ward for chronic psychotic patients.

A new type of hostel ward is described in which domestic activities take the place of attendance at a day centre or industrial workshop. Residents no longer depend on the institution for meals, cleaning, or social activities. The programme is resident-orientated, and individual treatment plans are designed and effected using a points system. The emphasis of group activities is on communication and living skills. The hostel ward is able to care for our most disabled patients who are thought to need 24-hour nursing care.

Activities of Daily Living↗
PubMed1984

Missed subcapital fractures.

Intracapsular femoral neck fractures, even when they are recognized and treated early, have a relatively high complication rate. Failure to diagnose these fractures can greatly increase the complication rate and make more radical surgery necessary. Reported are two cases of missed subcapital fractures. Both patients had continuing symptoms, eventually were hospitalized, and required arthroplastic procedures. The significance of missed subcapital fractures is discussed, as are guidelines for diagnosis and treatment.

Aged↗
PubMed1984

Septic arthritis of the knee in a 12-year-old hemophiliac.

A known pediatric hemophiliac was evaluated for what was thought to be a hemarthrosis of the knee. When the patient failed to respond to conventional treatment, the joint was aspirated and found to be septic. Septic arthritis is a rare complication of hemophilia and requires prompt recognition and treatment.

Arthritis, Infectious↗
PubMed1983

Serological analysis of the subgroup protein of rotavirus, using monoclonal antibodies.

Ten monoclones directed to the 42,000-dalton inner structural protein of rotavirus were analyzed. Eight monoclones reacted broadly with antigenic domains common to virtually all mammalian rotaviruses. Two monoclones had specificities similar or identical to previously characterized subgroup specificities. These subgroup monoclones were more efficient in detecting subgroup antigen than either hyperimmune or postinfection antisera. Using the subgroup monoclones, we determined that some animal as well as human rotavirus strains carry subgroup 2 specificity and that epizootic diarrhea of infant mice virus and turkey rotavirus are antigenically distinct from other mammalian rotavirus strains.

Animals↗
PubMed1982

I.V. glyceryl trinitrate: haemodynamic effects and clinical use in cardiac surgery.

A commercial preparation of glyceryl trinitrate for i.v. administration was assessed under both experimental and clinical conditions. The overall haemodynamic effects were beneficial during coronary artery grafting and aortic valve replacement, when the drug was given at a rate of 0.8 microgram kg-1 min-1 at which dose there was no appreciable effect on resistance vessels. No adverse side-effects occurred. There was no change in the activity of the preparation, whether diluted or not, over a 6-h period.

Aortic Valve Stenosis↗
PubMed1978

Effects of inhaled beclomethasone dipropionate and alternate-day prednisone on pituitary-adrenal function in children with chronic asthma.

Two corticosteroid regimens, alternate-day prednisone and inhaled beclomethasone dipropionate, have been more acceptable than daily oral corticosteroids for treatment of chronic asthma. To compare the effect of these regimens on hypothalamic-pituitary-adrenal function, 20 children with asthma were evaluated while receiving 20 to 40 mg of prednisone on alternate mornings or 400 to 800 microgram per day of inhaled beclomethasone dipropionate in divided daily doses; seven children requiring only non-corticosteroid medication served as controls. Early-morning serum cortisol concentration, urinary free-cortisol excretion and the 11-desoxycortisol response to metyrapone were decreased to a similar degree among children receiving both corticosteroid regimens in comparison with the control patients and were lowest when alternate-day prednisone and inhaled beclomethasone dipropionate were given together. Thus, inhaled beclomethasone dipropionate appears similar to alternate-day prednisone in its effect on hypothalamic-pituitary-adrenal function when used alone; the effect is additive when the two are used together.

Administration, Oral↗