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Biomedical subjects

A M Morris

Publications and source records attributed to A M Morris.

13 recordsLinked to original sources
PubMed1992

Disruption of circadian regulation by brain grafts that overexpress Alzheimer beta/A4 amyloid.

Alzheimer disease patients exhibit irregularities in the patterns of normally circadian (daily) rhythms. Alzheimer-type pathology has been reported in the hypothalamus and in the suprachiasmatic nuclei, the putative site of the circadian oscillator. We examined the relationship between the neuropathology of Alzheimer disease, as modeled by an animal system, and circadian dysregulation by grafting genetically transformed cells that overexpress beta/A4 amyloid into the suprachiasmatic nuclei of adult rats. Grafts of beta/A4-positive cells, but not of control cells, significantly altered the pattern of activity of implanted rats. Although experimental conditions included light-dark cycles that normally tend to drive rats to 24-h rhythms, animals with grafts of beta/A4-positive cells showed abnormally high levels of activity during the light phase in addition to a disrupted circadian pattern. Periodogram analysis demonstrated significant rhythms outside of a circadian range. The body temperature rhythm of these animals was also weak 6 weeks after grafting; however, unlike activity patterns, body temperature regained a circadian period by 8 weeks after cell implantation. These data indicate that disruption of circadian activity is a behavioral measure of the consequences of beta/A4 accumulation in brain implants.

Alzheimer Disease↗
PubMed1992

The P300 event-related potential. The effects of sleep deprivation.

We monitored 15 healthy young adults during 18 hours of sleep deprivation. Subjects were repeatedly tested on measures of the P300 (P3) event-related potential, reaction time, body temperature, and a subjective rating of fatigue. Statistically significant decreases in P3 amplitude (P < or = .01) and increases in P3 latency (P < or = .0001) were found during sleep deprivation. These changes correlated with body temperature and fatigue and were not due to circadian variation. Reaction time did not show a significant change over time. We conclude that the P3 potential is a more sensitive cognitive measure of sleep deprivation than reaction time, a measure commonly used in previous studies. We provide a review of the literature on the P3 and recommend the use of the P3 as a marker to examine sleep deprivation in health professionals.

Adult↗
PubMed1991

Doctors' hours.

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Consultants↗
PubMed1991

Cutaneous malignant melanoma: audit of the diagnostic process.

The results of a study of the diagnostic process in 202 cutaneous malignant melanomas over a 5-year period in one region are presented. Patient delay of more than 3 months was noted in at least 60% of cases, and delay after presentation was identified in 21% of the case histories. In 12% of the cases an opportunity for earlier diagnosis had been missed. The factors leading to delay in diagnosis are highlighted and the need for the dissemination of information relating to the early stages of the disease is emphasised.

Female↗
PubMed1978

Sauna bath burn.

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Burns↗
PubMed1978

The place of the cross-leg flap in reconstructive surgery of the lower leg and foot: a review of 165 cases.

In a series of 165 cross-leg flaps, 94 per cent were successful. Some degree of necrosis occurred in almost half of them. Major necrosis requiring split-skin grafting occurred in less than one-fifth. Thrombo-embolic complications were rare and mainly in the older age group. The retunr of sensation was good; better in the flap than in the donor site. The long-term results were good with a low complication rate. On weight-bearing surfaces the cross-leg flap skin stands up well to wear and tear.

Adolescent↗
PubMed1978

A gastrocnemius musculocutaneous flap.

The results of injection studies in cadavers and in vivo flap construction suggested that a flap based on the medial or lateral gastrocnemius muscle and the skin of the popliteal fossa draining to the long or short saphenous systems respectively provides a good length to breadth ratio flap without prior delay. Such a flap based on the medial gastrocnemius muscle was used successfully in 1 patient.

Adult↗
PubMedDate not supplied

Acute toxic nephropathies: clinical pathologic correlations.

Man's ever increasing exposure to numerous drugs and chemicals, which are the results of medical and industrial progress, produces a by-product of acute toxic nephropathies. These include acute toxic renal failure, drug-induced acute oliguric renal failure, acute hemorrhagic glomerulonephritis, nephrotic syndrome, tubular disturbances and potassium deficiency. In depth information is provided for the previously mentioned disorders.

Acute Kidney Injury↗
PubMedDate not supplied

Chronic toxic nephropathies--diagnosis and management.

As a result of industrial and medical progress, man is exposed to an ever changing array of chemicals, drugs and biological products. The kidneys are extremely vulnerable to chronic toxic effects of these substances. Although acute renal failure, nephrotic syndrome and renal tubular disorders result from acute nephrotoxicity, chronic renal failure with renal failure and hypertension result from chronic nephrotoxicity. Heavy metals, analgesic agents and antimicrobials are the common nephrotoxic substance producing chronic renal disease. Medical management consists of preventive exposure measures and early detection of nephrotoxicity by modern industrial medicine. In addition, early clinical diagnosis with appropriate management may prevent the need for chronic hemodialysis and renal transplantation.

Alcoholic Intoxication↗