Review of management of incidents involving exposure to blood in a London teaching hospital, 1989-91.

OBJECTIVE--To review management of incidents involving exposure to blood reported to an occupational health unit. DESIGN--Analysis of all reported incidents from January 1989 to June 1991. SETTING--London teaching hospital. SUBJECTS--447 health care workers and students. MAIN OUTCOME MEASURES--Immunisation against hepatitis B virus before exposure, proportion of known source patients tested for hepatitis B surface antigen and HIV antibodies, and reasons for not testing known source patients. RESULTS--447 incidents were reported: 337 sharps injuries and 110 other exposures. 310 staff reporting incidents (205 (82%) nurses) were already immune to hepatitis B virus, nearly always because of immunisation. 345 source patients were identified, 77 of whom had already been tested for hepatitis B surface antigen (28 positive results) and 58 for HIV antibodies (18 positive results). Of those not previously tested, 145 of 266 were subsequently tested for hepatitis B surface antigen (two positive) and 149 of 287 for HIV antibodies (none positive). The main reasons for not testing source patients were that the incident was not considered a risk, that the patient had gone home, and that the clinical team were unwilling to ask the patient. Specific hepatitis B immunoglobulin was given to 18 staff who were not immune and was avoided in 11 cases by a negative result for the patient. Prophylactic zidovudine was discussed but not given to any staff member. CONCLUSIONS--Management of exposure to blood is improved by widespread immunisation against hepatitis B virus and by knowledge of source patients'' hepatitis B virus and HIV status.     

Period shortening and phase shifting effects of ethanol on theGonyaulax glow rhythm

Summary In a number of organisms which exhibit circadian rhythmicity, a continuous exposure to ethanol at moderate (0.1%) concentrations is known to cause period lengthening. In studies of the effects of ethanol on the circadian luminescence glow rhythm of the marine dinoflagellateGonyaulax, we observed that 0.1% ethanol causes instead a period shortening. We have also found that ethanol pulses cause phase shifts, with little or no after-effects on the period of the circadian rhythm which continues thereafter.Abbreviation CT circadian time This work has been supported in part by a grant from the National Institutes of Health GM-19536 to J.W. Hastings, and by a Rackham Block Grant to Walter Taylor from the University of Michigan     

Oscillatory states of mitochondria. Studies on the oscillatory mechanism of liver and heart mitochondria

Oscillatory movements of ions across the inner membrane of liver and heart mitochondria in vitro have been investigated. Our results indicate that the inverse of the square of oscillatory period is linear with respect to (a) the permeant cation concentration; (b) the inverse of the permeant weak acid anion concentration, and (c) the rate of energyproduction. It has been shown that various factors contribute to damping of the oscillations. These factors include: substrate utilization, mitochondrial deterioration, imperfect mitochondrial synchronization, and, possibly, an oscillatory mechanism which dictates damping. An increased period length and extensive damping of oscillations occurs at a critical mitochondrial protein concentration (less than 0.6 mg protein/ml). Such inhibition can be reversed by the addition of cytochrome c.     

Post-transcriptional Gene Regulation by MicroRNA-194 Promotes Neuroendocrine Transdifferentiation in Prostate Cancer

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Acquisition of circadian bioluminescence data in Gonyaulax and an effect of the measurement procedure on the period of the rhythm

During measurements of the circadian (approximately 24-hr) rhythms of spontaneous bioluminescence in the marine dinoflagellate Gonyaulax polyedra, the individual cultures in vials were shielded from otherwise constant dim light for 1-3 min every 20-60 min by a photomultiplier housing that was moved from vial to vial. The high-frequency dark pulses caused a small but consistent shortening of the free-running circadian period, but there was no indication that the dark pulses caused entrainment. Hardware and software components of the microcomputer-controlled data collection system are described. A microcomputer controlled the movement of the photomultiplier and acquired the data via an analog-to-digital converter. The algorithms distinguished and separately recorded background glow, intermittent flashes, and total light from populations ranging in number from 10(3) to 10(5) cells in volumes from 1 to 10 ml. Fast video display techniques allowed continuous on-line viewing of incoming data, together with a display of the data recorded over the preceding day or two. Detection of mechanical and software errors coupled with recovery systems maintained high reliability of data collection.