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Biomedical subjects

M P Mahoney

Publications and source records attributed to M P Mahoney.

12 recordsLinked to original sources
PubMed1994

Dark goggles and bright light improve circadian rhythm adaptation to night-shift work.

We compared the contributions of bright light during the night shift and dark goggles during daylight for phase shifting the circadian rhythm of temperature to realign with a 12-hour shift of sleep. After 10 baseline days there were 8 night-work/day-sleep days. Temperature was continuously recorded from 50 subjects. There were four groups in a 2 x 2 design: light (bright, dim), goggles (yes, no). Subjects were exposed to bright light (about 5,000 lux) for 6 hours on the first 2 night shifts. Dim light was < 500 lux. Both bright light and goggles were significant factors for producing circadian rhythm phase shifts. The combination of bright light plus goggles was the most effective, whereas the combination of dim light and no goggles was the least effective. The temperature rhythm either phase advanced or phase delayed when it aligned with daytime sleep. However, when subjects did not have goggles only phase advances occurred. Goggles were necessary for producing phase delays. The most likely explanation is that daylight during the travel-home window after a night shift inhibits phase-delay shifts, and goggles can prevent this inhibition. Larger temperature-rhythm phase shifts were associated with better subjective daytime sleep, less subjective fatigue and better mood.

Adaptation, Physiological↗
PubMed1994

Pseudohyperkalaemia associated with hereditary spherocytosis in four members of a family.

Pseudohyperkalaemia was detected in four members of a family all of whom have hereditary spherocytosis with normal white blood cells and platelets counts. The degree of pseudohyperkalaemia was related to the time between sampling and cell separation, and inversely related to the temperature in which the sample was left to stand before cell separation. A fifth member of this family was free from both conditions. The association suggests linkage at a membrane level.

Adult↗
PubMed1993

Leptospirosis presenting as atypical pneumonia, respiratory failure and pyogenic meningitis.

A 20-year-old man who looked after a pack of hounds was admitted with a short history of headache, fever, haemoptysis and muscle cramps. Investigations showed type I respiratory failure with diffuse pneumonitis, pyogenic meningitis and raised liver enzymes. Leptospirosis was suspected and treated with the appropriate antibiotics leading to a full recovery. The diagnosis was confirmed by a titre of I/2560 to Leptospira icterohaemorrhagiae. The case illustrates an unusual presentation of this infection and argues for early antibiotic treatment.

Adult↗
PubMed1972

Plasmaphoresis and plasma exchange in the treatment of hyperlipaemia and xanthomatous neuropathy in patients with primary biliary cirrhosis.

Two patients with primary biliary cirrhosis who were increasingly incapacitated by xanthomatous neuropathy are described. Treatment with a low fat diet and cholestyramine was unhelpful but repeated plasmaphoresis by simple venesection in one and plasma exchange using an IBM blood cell separator in the other over a period of several months completely relieved the symptoms of the neuropathy, caused skin xanthomata to recede, and lowered plasma lipid levels in both patients. There was no evidence that this procedure was associated with any deleterious effects on the liver. The size of the cholesterol pool in xanthomata in one patient was estimated to be approximately 35 g, and from the plasma cholesterol response to plasmaphoresis at varying frequency it was suggested that the excess of cholesterol synthesis over degradation was less than 0.3 g/day in one patient and less than 0.4 g/day in the other. On the basis of the response in these patients it is suggested that the turnover rates of lipid pools are relatively slow in biliary cirrhosis and that cholesterol accumulation is more likely to be due to a reduced catabolic rate than to an increased synthetic rate of cholesterol. Plasmaphoresis or plasma exchange are useful methods of treatment for the rare patient afflicted by this resistant and distressing complication of biliary cirrhosis.

Adult↗