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Biomedical subjects

R Morin

Publications and source records attributed to R Morin.

At least 37 records · Page 2Linked to original sources
PubMed1985

Comparison of intraluminal and intravenous mediators of colonic response to eating.

Eating a 1000-kcal mixed meal stimulates an increase in distal colonic motility. Fat is the dietary component which is the major stimulant of colonic spike activity. In this study the colonic spike activity increased similarly after the mixed meal [19.1 +/- 2.4 spike potentials (SP)/30 min] and after the fat meal (19.4 +/- 5.4 SP/30 min). Fat stimulated a concentration-dependent increase in colonic motility only when in contact with the gastroduodenal mucosa. Intravenous administration of Liposyn (100 kcal/hr) did not stimulate an increase in colonic spike activity (3.3 +/- 1.3 SP/30 min) despite greater increase in plasma total fatty acid levels than after the oral ingestion of fat. In contrast both the oral ingestion and the intravenous administration of an amino acid mixture (Aminosyn) inhibited the gastrocolonic response after the 1000-kcal mixed meal. Thus, these studies demonstrate: (1) fat stimulates colonic motility only through direct mucosal contact, and (2) a mixture of amino acid inhibits colonic motility through either mucosal contact or by circulating in the plasma. The exact neurohumoral mechanisms involved in both of these effects is unknown at present.

Action Potentials↗
PubMed1983

Carbamazepine--erythromycin interaction leading to carbamazepine toxicity in four epileptic children.

We report four cases of carbamazepine toxicity in children associated with the concurrent administration of erythromycin. They all developed clinical toxicity (ataxia, dizziness, nausea, and vomiting) when erythromycin administration was begun; symptoms disappeared after erythromycin was discontinued. Serum carbamazepine levels were measured before, during, and, in most cases, after the toxic episodes. In all cases, there was a sharp increase in carbamazepine concentration after erythromycin therapy was begun and a rapid fall once erythromycin was discontinued. Our data support the previous suggestion that erythromycin interferes with the liver microsomal metabolism of carbamazepine with a subsequent increase in blood levels of the drug.

Carbamazepine↗
PubMed1983

[3H]imipramine labels sites on brain astroglial cells not related to serotonin uptake.

Brain astroglial cells, whether from a bulk isolated preparation or in culture, have been shown to take up serotonin actively. [3H]imipramine has been proposed as a specific label for serotonin uptake sites in brain. We therefore studied the binding of [3H]imipramine to C6 astroglial cells in culture to determine if some of the binding of this radioligand in brain homogenates is actually to serotonin transporting sites on glia. [3H]Imipramine binds saturably (Bmax = 202 fmol/mg protein) and with high affinity (KD = 1.72 nM) to C6 cells. This binding is competitively inhibited by other tricyclic antidepressants. The C6 cells actively transport [3H]serotonin with a Km of 2 microM and a Vmax of 1080 fmol/10(6) cells/min. However, the pharmacological profile for inhibition of serotonin uptake does not correlate with the pharmacological profile for inhibition of [3H]imipramine binding. These results suggest that the binding of [3H]imipramine to astroglial cells is not related to their capacity for active uptake of serotonin. Further, in brain homogenates, some of the binding of [3H]imipramine may not be to neuronal uptake sites but rather may be to sites on astroglial cells.

Animals↗
PubMed1979

Hypocholesterolemic effect of yogurt and milk.

In order to determine the effect of milk products on serum cholesterol, triglycerides, and diet, 54 volunteers were studied for varying periods with dietary supplementation of nonpasteurized yogurt, pasteurized yogurt and 2% butterfat milk. Serum cholesterol was significantly reduced by 5 to 10% after 1 week of supplementation with either nonpasteurized or pasteurized yogurt; 2% butterfat milk reduced serum cholesterol to a smaller and less significant effect. Serum triglycerides were unaffected by the diet and dietary intake studies confirmed that intake of other nutrients remained relatively stable throughout the study. Supplementation of diet with yogurt may have a helpful hypocholesterolemic effect.

Adult↗
PubMed1975

[Effect of sodium salicylate on the "in vitro" development of RNA viruses (author's transl)].

Sodium salicylate 10(-3) M is able to limit the number of plaques induced by RNA viruses on monkey kidney cell cultures (Cercopithecus aethiops and Macaccus rhesus). However, the inhibition rate changes with the virus type or even the strain used. Poliovirus 2, Coxsackie B3, echovirus and reovirus 1 were the most susceptible to the inhibitory effect of the drug. Latent infection caused by SV5 decreases the antiviral activity of salicylate. The stages of the poliovirus type 2 growth affected by sodium salicylate, were studied. The drug has no direct activity on the infectivity of the virus. It decreases adsorption and penetration. In spite of heavy virus concentration (10(-5,5) to 10(-7)) ID/ml) the eclipse phase is delayed about 3 hours. After 6 hours, viral maturation proceeds and reaches the same level as the controls, and virus quantities recovered are equivalent after 12 hours. Viral infectious RNA fails to induce plaques on salicylate treated cultures. The drug seems to act during the eclipse phase.

Adenoviruses, Simian↗
PubMedDate not supplied

A new approach to gas field ion sources.

A new approach to gas field ion sources is described. It is based on a structure made by inserting a field emission tip inside a small diameter tube. The tube supplies gas to the tip from a high-pressure chamber into a high-vacuum chamber where ionization takes place. Comparison of projection electron and ion micrographs shows that ionization results from a field ionization process taking place at the very end of the tip. Emission currents in the 10nA range, for a few kV emission voltages, are obtained with various gases including neon, air and hydrogen. Lifetime experiments with H(2) show stable emission for days.

Journal Article↗
PubMedDate not supplied

Accuracy of implanted port placement with the use of the electromagnetic CathTrack catheter locator system.

PURPOSE: To test whether an electromagnetic guidance system such as CathTrack would allow long-term central venous access devices to be reliably placed at a decreased cost and without radiation exposure to patients and staff. The following study was undertaken to verify accuracy of the CathTrack system for catheter placement and to develop guidelines for its use. METHODS: Twenty-nine consecutive patients were prospectively enrolled in the study and taken to the operating room for implantation of a permanent central venous access port. By protocol, the CathTrack system was used to guide initial catheter positioning using the center of the third intercostal space along the right sternal border as the desired external target. Fluoroscopy was then used to visualize tip position and relocate the catheter tip to the exact position desired by the surgeon. RESULTS: Catheter placement using the CathTrack system was successfully accomplished in 27 out of 29 patients. In two instances CathTrack was abandoned and fluoroscopy utilized because of difficulty in threading the initial guidewire into the superior vena cava. CONCLUSION: The CathTrack electromagnetic locator system can be used to reliably position catheters for the establishment of long-term central venous access. Decreased cost and elimination of radiation exposure are distinct advantages of this system over fluoroscopy.

Journal Article↗