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Biomedical subjects

E A Wright

Publications and source records attributed to E A Wright.

At least 73 records · Page 4Linked to original sources
PubMed1986

Renal biopsy in Saudi children with nephrotic syndrome not responsive to corticosteroid: a preliminary report.

Percutaneous renal biopsy was done in 25 Saudi children whose nephrotic syndrome did not respond to prednisolone. The histologic diagnosis was mesangial proliferative glomerulonephritis in 11 cases; an additional two biopsies had features of both mesangial proliferative glomerulonephritis and focal segmental glomerulosclerosis. Immunofluorescence was abnormal in 16 out of 21 patients, with IgM as the most frequently detected immunogen.

Adolescent↗
PubMed1985

Developmental assessment of spinal cord and cortical evoked potentials after tibial nerve stimulation: effects of age and stature on normative data during childhood.

Somesthetic information from lower extremities is processed by cerebral cortex after traversing the sensory pathways of peripheral nerve, spinal cord, brain-stem and thalamus. Clinical utility of somatosensory evoked potentials (SSEPs) during human development requires systematic analysis of normative data acquired during various stages of body growth and nervous system maturation. Accordingly, SSEPs after tibial nerve stimulation were studied in 32 normal awake children (1-8 years old) and compared with values obtained in young adults (18-40 years old). Potentials were recorded from the tibial nerve (N5), first lumbar spinous process (N14), seventh cervical spinous process (N20) and from the scalp, 2 cm behind the vertex (P28). In all children studied, the N5, N14 and N20 latencies were positively correlated with age and height yielding a predictive nomogram. An extremely variable electropositive cortical SSEP was recorded from Cz' which did not show a highly predictable linear relationship in association with a relatively poor correlation coefficient for height and age. It may be concluded that between 1 and 8 years of normal postnatal development, latencies reflecting peripheral nerve and lumbar spinal cord vary directly with height and age and can be represented by a simple cable model of a lengthening myelinated pathway. In contrast, the latency of the cortical SSEP reflects asynchronous maturation of elongating polysynaptic pathways and apparently requires a more complex model for prediction in order to enhance its clinical utility.

Adolescent↗
PubMed1985

A randomized controlled trial of quality assurance in sixteen ambulatory care practices.

A crossover randomized controlled trial of cycles of quality assurance in 16 primary care (8 medical, 8 pediatric) group practices was conducted. Of four medical and four pediatric tasks important to patient outcome, two were randomly assigned to experimental intervention (a quality assurance cycle), and two were also measured and used as blinded controls for each medical or pediatric group practice. Task performance was measured in each group for 12 months prior to, 9 months during, and 9 months after the experimental intervention, using as a performance score the percentage of evaluation criteria failed of those applicable to a case. As a result of quality assurance intervention, quality of performance was significantly improved in two of the tasks (P less than 0.0001, with 6.7, and 9.8 percentage points improvement), and marginally improved in one task (P = 0.06, 5.7 percentage points improvement). Surprisingly, tasks with lower perceived effect on patient health (low physician motivation) had greater improvement in quality. Unimproved tasks were associated with the perceived need for delivery system changes beyond the immediate control of the individual practitioner.

Adolescent↗
PubMed1985

Features of the geriatric EEG: age-dependent incidence of POSTS.

Positive occipital sharp transients of sleep (POSTS) are well recognized as a normal electroencephalographic phenomenon in young to middle-aged persons, but little comment has been made concerning their occurrence in geriatric age groups. This study encompassing 365 electroencephalograms, showing POSTS among patients aged 22 to 86 years, demonstrates that the presence of POSTS is not an age limited occurrence, but extends over a wide age range into the later decades of life. Though the incidence of POSTS declined with advancing age, the diminution was not striking until after age 70. POSTS appeared only in normal and mildly abnormal EEGs. POSTS did not occur in markedly abnormal EEGs, and thus they resemble other features of normal sleep including sleep spindles and K-complexes.

Adult↗
PubMed1984

Resource requirements for evaluating ambulatory health care.

We implemented the most frequently used form of quality assurance activity: abstracting information on the quality of patient care from medical records and communicating findings to providers in 16 ambulatory care groups. Site providers accepted the evaluation criteria, agreed that deficiencies in care were detected, and, for some medical tasks, effected improvements in care. Direct costs in 1980 dollars for the quality assurance cycle including data system development were $46 per evaluated case. Per-case costs varied considerably among tasks, decreased with larger numbers of cases and as experience grew, and were reduced through computerization. Measured costs were high due to: a demanding research design; our extended accounting of direct, indirect, and induced costs; and the substantial resource requirements of rigorously performed evaluations.

Ambulatory Care↗
PubMed1983

Bone changes in mice after prolonged continuous exposure to a high concentration of carbon monoxide.

Quantitative and qualitative pathological changes in mouse bones are described after continuous exposure to 0.24% v/v of carbon monoxide in air for periods of up to 180 days. Planimetric measurements of five bones (parietal bone, sternum, lumbar vertebrae, ribs and shafts of femurs) showed a considerable increase in the amount of bone tissue in all bones except the femurs. The greatest amount of new bone formation was found, in decreasing order, in the skull, ribs, lumbar vertebrae and sternal segments. The cortex of the femur shafts showed some thinning, although there was more trabecular bone in the metaphyses. At the same time an expansion of marrow cavities was found in ribs, parietal bones and femurs. Possible pathomechanisms responsible for the excessive bone formation are explored. It is suggested that an increased rate of blood flow through the bone and marrow tissues played an important role.

Animals↗
PubMed1983

Effect of castration and testosterone propionate on mouse vibrissae.

Vibrissae of normal mice were measured for six cycles starting at birth. Groups of immature male albino mice were castrated at 21 days of age when E, F, G and H (Danforth nomenclature, 1925) vibrissae were in their first cycle of growth. Levels of testosterone in their peripheral plasma were reduced to about one tenth of the normal. The final length achieved by their vibrissae in all subsequent cycles was shorter than that of normal mice. Another group of immature male mice were treated with implants of testosterone propionate to give plasma levels of approximately five to ten times normal. Their vibrissae showed a significant increase in final length in all growth cycles before and after sexual maturation. Vibrissae of adult male mice treated with excess testosterone showed a significant increase in final length at the end of the growth cycle immediately after commencement of treatment. On the other hand, vibrissae of castrated adult mice showed a significant decrease in final length in the second successive cycle after castration. The rate of growth of all vibrissae remained unchanged. Changes in their final length were brought about by changes in the period of growth. Castrated mice had a slightly longer resting period.

Animals↗
PubMed1983

The cost of quality assurance in medicine.

Cost analysis has been frequently neglected in program evaluations but is currently of high relevance in policy decisions on quality assurance in medicine. The Ambulatory Care Medical Audit Demonstration (ACMAD) Project implemented and evaluated a program of medical record-based quality assurance in eleven sites for nine medical topics. Total direct costs for the project were $1.22 million over five years; indirect costs, $694,000. A computerized data system enabled disaggregation of the cost data by person, timing, type of work, project phase, health topic, health center, and research or operational nature. Of the costs incurred, 79% were for operational reasons, with 21% incurred for research reasons. Costs per audited case were 31% higher in hospitals than in neighborhood health centers. Audit topics of low per-case costs tended to have automated case findings, straightforward and limited abstracting, little need to examine multiple visits, and a low proportion of case-found patients ineligible for audit.

Ambulatory Care↗
PubMed1983

The short term effects of a supra-lethal dose of irradiation and changes in the environmental temperature on the growth of tail bones of the mouse.

The growth and histological features of the tail vertebrae of young mice (31 day old) were observed for 48 h after transference from a cold (8 degrees) to a hot (33 degrees) environment. Some mice received a massive (5000 rad) dose of X-ray to the tail. Less than 2 h after housing the animals in the heat there was a period of very rapid growth lasting 12 h after which time growth slowed but was still much greater than the animals in the cold. Animals whose tails were irradiated (and also put in the heat) showed the same rapid growth for 12 h but after this growth ceased. Evidence is provided which shows that the initial rapid growth in the heat is due to an abnormal increase in the linear dimensions of the hypertrophic cells of the growth plate. This is most marked in the hot-irradiated animals.

Animals↗
PubMed1983

The effects of changes in the environmental temperature on the growth of tail bones in the mouse.

The tails of baby mice grow rapidly and independently of environmental temperature because they are kept warm by their mothers. After weaning, at approximately 3 weeks of age, tail growth is strictly related to environmental temperatures. During the first 2 weeks after weaning growth rates of 1.2-1.4 mm/day/tail were seen at 33 degrees and a maximum of 2.43 mm/day/tail was observed in one group kept at 36 degrees. Animals kept at 8 degrees or 4 degrees showed tail growth rates of 0.4 mm/day or less. However, the tails of animals transferred from either hot to cold or cold to hot during their first 2 weeks after weaning immediately grew at the same rate as those of animals kept in these conditions continuously, thus indicating that heat was acting directly on bone growth. The tails of animals kept continuously in the hot environment at 33 degrees completed their growth early so that their growth rate fell below that of controls after about 3 weeks of treatment (when they were 6-7 weeks old) and below that of "cold" animals after about 4 weeks (7-8 weeks old). The tails of the "control" and "cold" animals grew slowly for a very long time, 150-195 days. Even so, because of the very rapid early growth of tails in the hot environment, their final length was always greater than either the "control" or "cold" tails.

Aging↗
PubMed1983

The effects of changes in the environmental temperature on the growth of bone in the mouse. Radiological and morphological study.

Groups of 25-day-old mice were kept at 33 degrees, 21 degrees and 8 degrees for up to 195 days. Measurements and observations on length, width, gross and microscopic structure using radiological and histological techniques were made on central and peripheral bones. Tail bones of animals kept at 33 degrees grew longer and faster than those in the cold but also closed their epiphyses earlier. The diaphyses of "hot" vertebrae were cylindrical but "cold" and "control" vertebrae were of narrower diameter in their mid-diaphyses compared to their distal ends producing a "waisted" appearance. The "cold" vertebrae in addition showed thickened cortical bone and more woven bone in the marrow cavity. These changes were interpreted as indicating a disproportionate sensitivity of external apposition of cortical bone to cold. The internal remodelling of bone as the vertebrae grew was only affected by the coldest conditions and accounted for the thickened cortex and denser woven bone in the marrow cavity.

Aging↗
PubMed1983

Treatment of mouse mammary tumors using combined hyperthermia and ischemia.

To investigate ischemic potentiation of thermal cell killing, mammary carcinomas transplanted to the legs or tails of C3H mice were treated with hyperthermia using rubber-lined compression cuffs. During treatment, warm water was circulated through the cuffs under pressure so that blood flow to the contained tumor-bearing limbs was interrupted. Ninety min at 41.5, 42.0, or 42.5 degrees and pressures between 60 and 135 mm Hg destroyed about 50% of tumors but damaged the normal tissues. Damage increased with the degree of compression. Intermittent pressure application was therefore adopted (five 18-min periods at 80 to 90 mm Hg alternating with four periods of 5 min at zero pressure). This favored the normal tissues, a high cure rate being maintained (73%) with damage to normal tissue virtually eliminated. The most satisfactory explanation of these results is a selective heat sensitivity, augmented by ischemia, on the part of tumor blood vessels. The success of intermittent treatment is then attributable to progressive impairment of the blood supply to the tumors, preventing the heat dissipation and relief of conditions such as acidity and nutrient deficiency which would otherwise result from periodic restoration of the circulation.

Animals↗
PubMed1981

Effects of environmental temperature on haemopoietic stem cells in the tails of mice.

Using the endogenous spleen colony assay method of Till & McCulloch (1963), the numbers of haemopoietic stem cells present in the bone marrow in the tails of mice were estimated under different environmental temperatures. Compared to animals kept at 22--26 degrees C, mice transferred to an kept at 36.5 degrees C showed a doubling of colony-forming units in the tail in 1--4 weeks. Exposing them to 8 degrees C caused a significant depopulation to approximately one-third in 3--4 weeks. By transferring the mice from one temperature extreme to another these changes could be reversed. Tail marrow depleted of viable stem cells by X-irradiation was repopulated within approximately 3 weeks in animals kept at room temperature or above but this process was inhibited in the cold.

Animals↗
PubMed1980

The effect of chemotherapy on occult metastases after surgical removal of a non-immunogenic mouse carcinoma.

A transplantable non-immunogenic murine carcinoma of spontaneous origin, WHT Carcinoma N-C (Hewitt), was used to assess the effectiveness of melphalan (Ml) and/or methotrexate (Mx) for treatment of occult metastatic disease following surgical excision of primary tumors. Early surgical excision alone cured 66% of mice; later excision gave no cures. Maximum sublethal doses of chemotherapy rarely cured mice of metastases but did extend their survival time by up to 66% as compared with mice subjected to excision only. The influence of excision and chemotherapy on the frequency of local recurrence or pulmonary metastasis is discussed. Extrapulmonary metastases were 2.5 times more frequent in long-term than in short-term survivors, independently of treatment.

Animals↗