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Biomedical subjects

R Gagnon

Publications and source records attributed to R Gagnon.

At least 109 records · Page 6Linked to original sources

Effects of vibratory acoustic stimulation on human fetal breathing and gross fetal body movements near term.

Twenty-five pregnant women between 36 and 40 weeks' gestational age were studied to examine effects of a 5-second external vibratory acoustic stimulus on fetal breathing and gross fetal body movement patterns. When the study period was compared with the control period, there was an immediate significant decrease in the incidence of fetal breathing movements that persisted for 1 hour after the stimulus. Moreover the fetal breathing pattern was more irregular for the hour after the stimulus. There was also a significant but delayed increase in the incidence of gross fetal body movements that persisted for 1 hour after the stimulus. We hypothesize that an external vibratory acoustic stimulus causes a change from a state of sleep to a state of wakefulness in near-term healthy fetuses.

Acoustic Stimulation↗

Stimulation of human fetuses with sound and vibration.

Forty pregnant women between 30 and 42 weeks' gestational age were studied to examine the effects of external sound and vibration on the fetal heart rate. A significant increase in the mean duration and amplitude of the first acceleration after sound stimulus was found when these values were compared with the control values. Conversely the mean time to the first acceleration in the control period was greater than that in the stimulated period. There was a significant increase in the mean duration of fetal heart rate accelerations, the mean amplitude of fetal heart rate accelerations, and the total time spent in accelerations up to 15 minutes after the sound stimulus as compared with the control period. There was no change in the number of accelerations following the sound stimulus compared to control. These data suggest that vibratory acoustic stimuli may influence patterns of fetal heart rate during human pregnancy.

Acoustic Stimulation↗

Dialyser reuse: a study in applied medical ethics.

A dialysis unit's introduction of automated recycling of dialysers is described. The responses of the staff and the patients are outlined, along with the pertinent ethical issues. Suggestions regarding the educational processes necessary with any innovation in long-term medical care are discussed.

Consumer Behavior↗

Consent to dialyzer reuse: is it ethically necessary?

It is argued that consent by the patient to reuse dialyzers which have been mechanically cleansed is not required provided adequate standards of practice and safety are utilized. Based on medical benefits, administrative order and cost saving we propose that specific informed consent for such reuse should not be mandatory and that it could at times be unhelpful, both to care givers and recipients.

Comprehension↗

Prolonged dialyzer reuse.

Clearance of urea, creatinine, phosphate and B12 in dialyzers reused up to 30 times were unchanged from the initial values. Residual formalin values were within acceptable levels and in several thousand dialyses no untoward reactions of any sort attributable to reuse were encountered. Neutropenia was constantly present with dialyzers prepared by automated reuse.

Creatinine↗

Antibody dependent cell mediated cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) in 229 sera from human renal allograft recipients.

Comparison between CDC and ADCC in a human allogeneic model using the same cytotoxicity marker, i.e. 51Cr release from labelled target cells, provided a better definition of the optimal technical conditions for revealing ADCC. Testing 229 sera from human renal allograft recipients after transplantation, we found that CDC is detected only during rejection (43% of cases) whereas ADCC can be found both in those recipients tolerating their grafts and in those undergoing rejection, more frequently in the former than in the latter (39% vs. 21%, p less than 0.05). These in vivo results and other in vitro experiments support the assumption that two distinct varieties of antibody can mediate the in vitro ADCC phenomenon, some directed against the A, B and C HLA loci and having a deleterious effect on the graft, and others capable of exerting a protective effect and which could be directed against D related HLA determinants.

Antibody-Dependent Cell Cytotoxicity↗

Effects of fluoride on bone in chronic renal failure.

Fluoride is concentrated in the bones of patients with chronic renal failure when fluoridated water is used during hemodialysis. Excessive osteoid is produced that is not normally mineralized and severe osteomalacia occurs. Electron microscopical examination of iliac crest bone biopsy specimens from four patients suggests that fluoride induces the synthesis of disarrayed collagen by the activated osteoblasts. Collagen fibers were found to be normal in size and in axial periodicity.

Adult↗