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Biomedical subjects

J Stevens

Publications and source records attributed to J Stevens.

At least 415 records · Page 23Linked to original sources
PubMedDate not supplied

Towards an economic model of the Dutch health care sector.

This paper describes the construction of a model of the Dutch health care sector. It discusses the behaviour of patients, general practitioners, medical specialists and hospital managers. It also analyses the various ways the actors interact, such as general practitioners supplying the services demanded by patients, specialists dispatching referrals made by general practitioners or hospital managers boosting output to match an increasing amount of specialist services. Numerical simulations illustrate the various mechanisms in the model.

Computer Simulation↗
PubMedDate not supplied

Biomedical imaging modalities: a tutorial.

The introduction of advanced imaging technologies has improved significantly the quality of medical care available to patients. Non-invasive imaging modalities allow a physician to make increasingly accurate diagnoses and render precise and measured modes of treatment. Current uses of imaging technologies include laboratory medicine, surgery, radiation therapy, nuclear medicine, and diagnostic radiology. This paper provides an overview of most of the popular imaging modalities currently in clinical use. It is hoped that a general understanding of the modality from which an image is derived will help researchers in the subsequent analysis of the image data.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Surgical treatment of low backache and sciatica.

A comparison between 86 patients with low back pain who underwent surgery and 32 who did not showed that laminectomy is an effective treatment for many patients in whom conservative treatment has failed. Surgery should be undertaken sooner rather than later (preferably within a year), both because a good outcome is less likely with longer duration of symptoms and because long periods of disability and time off work can in this way be avoided.

Adult↗
PubMedDate not supplied

The evolution of trypanosomes infecting humans and primates.

Based on phylogenetic analysis of 18S rRNA sequences and clade taxon composition, this paper adopts a biogeographical approach to understanding the evolutionary relationships of the human and primate infective trypanosomes, Trypanosoma cruzi, T. brucei, T. rangeli and T. cyclops. Results indicate that these parasites have divergent origins and fundamentally different patterns of evolution. T. cruzi is placed in a clade with T. rangeli and trypanosomes specific to bats and a kangaroo. The predominantly South American and Australian origins of parasites within this clade suggest an ancient southern super-continent origin for ancestral T. cruzi, possibly in marsupials. T. brucei clusters exclusively with mammalian, salivarian trypanosomes of African origin, suggesting an evolutionary history confined to Africa, while T. cyclops, from an Asian primate appears to have evolved separately and is placed in a clade with T. (Megatrypanum) species. Relating clade taxon composition to palaeogeographic evidence, the divergence of T. brucei and T. cruzi can be dated to the mid-Cretaceous, around 100 million years before present, following the separation of Africa, South America and Euramerica. Such an estimate of divergence time is considerably more recent than those of most previous studies based on molecular clock methods. Perhaps significantly, Salivarian trypanosomes appear, from these data, to be evolving several times faster than Schizotrypanum species, a factor which may have contributed to previous anomalous estimates of divergence times.

Animals↗
PubMedDate not supplied

The trypanosomatid evolution workshop London School of Hygiene and Tropical Medicine. 17-18 February 2000.

The trypanosome evolution workshop, a joint meeting of the University of Exeter and the London School of Hygiene and Tropical Medicine, focused on topics relating to trypanosomatid and vector evolution. The meeting, sponsored by The Wellcome Trust, The Special Programme for Research and Training in Tropical Disease of World Health Organization and the British Section of the Society of Protozoologists, brought together an international group of experts who presented papers on a wide range of topics including parasite and vector phylogenies, molecular methodology and relevant biogeographical data.

Animals↗
PubMedDate not supplied

Outpatient management of diabetes mellitus with patient education to increase dietary carbohydrate and fiber.

The impact of patient education on dietary fiber intake, diabetes control, and serum lipids was examined in patients with non-insulin-dependent diabetes mellitus. Customary outpatient personnel and procedures were used to teach three diet plans: the American Diabetes Association (ADA) diet, the ADA diet modified to increase high-fiber, high-carbohydrate foods (IF), and the IF diet supplemented with oat bran (IFOB). A control group was instructed on foot care to provide teaching visits. Fifty-two patients were recruited from an outpatient clinic and studied over a 6-wk period. Subjects were of low socioeconomic status and had completed a mean of 8.3 yr of education. Patients instructed to increase their intake of high-fiber foods reported a doubling of fiber intake and tolerated the diets well. Increased fiber and carbohydrate intake and decreased fat intake were associated with reductions in fasting plasma glucose levels. Increased fiber intake was also associated with reductions in total serum cholesterol and high-density lipoprotein cholesterol levels. Changes in fiber, carbohydrate, and fat intake were unrelated to changes in weight, serum insulin levels, or hemoglobin A1c levels over the study period.

Adult↗
PubMedDate not supplied

Development and reliability of a Telephone-Administered Perceived Racism Scale (TPRS): a tool for epidemiological use.

The conceptualization of perceived racism as a chronic stressor is relatively new to epidemiology. The Telephone-Administered Perceived Racism Scale (TPRS) captures the complexity of racism within five scales: Experience of Racism (by Blacks as a group and by the respondent), Emotional Responses, Behavioral Responses, Concern for Child(ren), and Past Experiences of Racism. The TPRS was developed for employed Black women. Exploratory factor analyses and tests of internal consistency were completed with 476 Black women, aged 36-53. Factor analyses on their responses to racism yielded five factors: passive emotions, active emotions, passive behaviors, internal active behaviors, and external active behaviors. Alpha reliability values ranged from 0.75 to 0.80 for the active and passive emotions subscales, from 0.59 to 0.69 for the passive behaviors subscale, and greater than 0.76 for both active behaviors subscales. Alpha reliabilities were 0.82, 0.90, 0.88, and 0.82 for Past Experiences, Concern for Child(ren), Experience of Racism--Personal, and Experience of Racism--Group, respectively. Another 30 Black women were queried for test-retest reliability, with values ranging from 0.61 to 0.82. The TPRS was found to be reliable and should serve as a useful epidemiological tool in the examination of the effects of perceived racism on Black women's health.

Adult↗