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Biomedical subjects

J Gerard

Publications and source records attributed to J Gerard.

30 records · Page 2Linked to original sources
PubMed1977

Correlation of variations in intraluminal pressure and potential differences in the perfused colen.

To investigate the nature of variations in the large intestine potential differences, a continuous perfusion of isotonic saline was carried out in the colon of 14 rats. Intraluminal pressure and potential differences between the lumen and the peritoneal cavity were continuously and simultaneously recorded, while impedance of the system and respiration were also constantly monitored. To obtain a quantitative evaluation of the data, Fast Fouier Transform was performed on the signals and their derivatives which were auto- and cross-correlated. While there was no obvious relation between pressure and potential in the unperfused colon, there was clear visual qualirative evidence that, during steady state conditions of perfusion, an increase in intraluminal pressure was accompanied by a decrease in potential differences, while impedance of the recording system remained unchanged. Computer analysis disclosed four narrow ranges of stable frequencies for both pressure and potential. They were centred around 0-3, 1-75, 10-7, and 75 cycles per minute, the latter being synchronous with respiration. It is concluded that the variations of potential differences recorded during perfusion, a well-know phenomenon, are not electrical artefacts: the fast rhythm is probably induced by respiration, which increases intracolonic pressure and that, in turn, reduces the absolute value of potential differences, which remain negative mucosa versus serosa. The slower rhythms are synchronous for pressure and potential. Mechanisms responsible for the decrease in potential related to the increase in pressure remain unknown.

Animals↗
PubMed1976

The genesis of bowel sounds: influence of viscus and gastrointestinal content.

This study was undertaken to try to solve the controversy about the influence of gastrointestinal contents on the genesis of bowel sounds, and to probe the respective importance of the various abdominal viscera. Eleven healthy volunteers were intubated by mouth with a multiple-lumen tube. Bowel sounds were recorded for 10 min when the tube was in the stomach, the upper jejunum, and the cecum, while it was left intact in situ, or perfused with isotonic saline (15 ml per min), or with an equal (7.5 ml per min of each) mixture of isotonic saline and air. Using a previously developed method, a computer analysis was made of the recording without any human intervention during the treatment of data. An analysis of variance demonstrated that the effect of perfusion varied according to site, with 46% of counted sounds while the tube was in the stomach, 32% in the jejunum, and 22% in the colon (P less than 0.05). There were two types of sounds: some exceeded in amplitude a preset threshold, and thus were picked up by the computer, but their average absolute value for 20 msec remained inferior to another preset threshold. Their number was kept in memory (NS--sounds having an amplitude exceeding a threshold S1, expressed in number per 10 min). A second type of sounds also exceeded the present threshold but their average absolute value for 20 msec also exceeded another preset threshold. Their number (NE--sounds having an amplitude exceeding the thershold S1 but having also a 20-msec average amplitude above another threshold S2, expressed in number per 10 min) was also memorized. The latter group was composed of two types of sounds: some had a limited spectrum of low frequency (100 Hz) and were of high amplitude and short (congruent to 5 msec) duration (NE1); some others had a higher and more dispersed frequency centered around 300 Hz (NE2). Fifty per cent of high energy (NE) sounds appeared while the tube was in the stomach, 30% in the colon, and 20% in the jejunum (P less than 0.005). Short and high amplitude sounds (NE1) were counted more often (43%) when it was in the colon than in the stomach (38%) and the jejunum (19%) (P less than 0.025), and this was confirmed (P less than 0.005) by a study of the ratio of NE1/NE. On the contrary, higher frequency sounds (NE2) were present more often when the tube was in the stomach (59%) than in the jejunum (24%) and in the colon (17%) (P less than 0.005). There was no influence of the presence of the unperfused tube on the genesis of bowel sounds in different sites (P greater than 0.05). In the stomach and the colon perfusion of the air/saline mixture increased the number of sounds (P less than 0.025) and all types of sounds in the stomach (P less than 0.025), whereas in the jejunum it was the perfusion of saline which increased them (P less than 0.025). It is concluded that the stomach is the most active site of production of bowel sounds, followed by the colon and then the small bowel, that sounds differ in different sites, and that all this is influenced by viscus content.

Cecum↗
PubMed1975

Plasma glucagon levels in normal women during pregnancy.

Increased plasma pancreatic glucagon concentrations have been reported during various states of decreased glucose tolerance. In vitro studies have demonstrated that human somatomammotropin stimulates glucagon release. The present investigation aimed at evaluating the role of plasma flucagon in the insulin resistance associated with normal pregnancy. Postprandial samples of plasma were obtained from 156 pregnant women between the 5th and the 40th week of pregnancy and were assayed for blood glucose, plasma insulin, glucagon and free fatty acids. Plasma insulin showed a gradual increase during pregnancy, and reached its maximal values during the last trimester. A moderate but significant increase in plasma glucagon was present between the 16th and the 28th week of gestation, whereas during the first and the last trimester of pregnancy its concentration was similar to that in non pregnant women. Intravenous glucose tolerance was performed during the last trimester and in a group of non pregnant control women. The slight decrease in glucose tolerance and the marked hyperinsulinemia associated with late pregnancy were accompanied by a more rapid and more pronounced decrease in plasma glucagon. A rapid and sustained decrease in glucagon was also observed when plasma FFA were raised by the intravenous administration of a triglyceride emulsion and heparin. These data suggest that glucagon is not involved in the insulin resistance associated with normal human pregnancy.

Adult↗
PubMedDate not supplied

Puncture wounds to the foot.

Puncture wounds to the foot are common presenting problems in most busy emergency departments. Although seemingly benign, the sequelae after simple puncture wounds to the foot can include cellulitis, retained foreign bodies, or even osteomyelitis. Inadequate scientific research on this topic has left only anecdotal or retrospective reports for review in the medical literature. Antibiotics, radiographs, or surgical exploration in the management of puncture wounds to the foot all lack clinical studies to support their use. This review summarizes the literature and points to the inconsistencies in the management of puncture wounds to the foot.

Cellulitis↗