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Biomedical subjects

J Collin

Publications and source records attributed to J Collin.

At least 145 records · Page 8Linked to original sources
PubMed1984

[Correlation between the mass and diameter of the left ventricle. Physiologic and physiopathologic consequences].

109 echocardiograms were recorded in 109 subjects, consisting of 51 hypertensive patients and 58 normal subjects, in order to study the correlation between hypertrophy and dilatation. The correlation between the left ventricular mass (LVM) and the end-diastolic left ventricular diameter (Dd) is highly significant (r = 0.72; p less than 0.001). This relation follows a sigmoid curve with two asymptotes for y (LVM) = 0 and y = M (M : estimated upper limit of the reaction of the left ventricle to hypertrophy, expressed in g) with the following formula: (Formula: see text). This relation reflects the adaptation of the LVM to a defined end-diastolic volume in physiological and pathological situations. This adaptation tends to maintain the stress exerted on the left ventricular wall at a constant value. On the basis of this relation, we can define three types of response of the LVM to the diameter: adequate hypertrophy follows the relation in normal limits (+/- 2 SD); inadequate hypertrophy, where the LVM is insufficient in relation to the Dd and inappropriate hypertrophy, where the LVM is exaggerated. Most of the subjects were distributed along the curve, below the point of inflection (corresponding to a Dd of 6.25 cm). Only a few hypertensive subjects were found above this point. The presence of inadequate hypertrophy seems to imply an intrinsic disease of the myocardium which limits normal regulation. Finally, if the stimulus responsible for hypertrophy is removed, the reaction should be reversible, at least to a certain degree.

Adolescent↗
PubMed1983

Effects of retrograde luminal perfusion of the canine jejunum on intestinal absorption and myoelectrical activity.

The effects of retrograde luminal perfusion of a 75 cm jejunal segment on absorption, transit time and myoelectrical activity were studied in four dogs. Retrograde perfusion increased jejunal absorption of water (0.016-0.021 ml cm intestinal length-1 min-1. P less than 0.001) together with sodium (1.15-1.82 mumol cm-1 min-1; P less than 0.001) and glucose (1.98-2.27 mumol cm-1 min-1; P less than 0.01). Mean jejunal transit time was prolonged (9.2-13.9 min; P less than 0.001) and jejunal spike activity was reduced compared with antegrade perfusion (14.5-4% of slow wave frequency; P less than 0.01). These results suggest that the reversal of small bowel segments in the treatment of the short bowel syndrome can result in an increase in absorption from the reversed segment itself in addition to any effect from delayed transit in the proximal bowel.

Action Potentials↗
PubMed1983

[Neonatal hypocalcemia in 2 twins revealing maternal hyperparathyroidism. A review of the literature].

The authors report the case of dizygotic twins suffering from transitory neonatal hypoparathyroidy and leading to the diagnosis of maternal hyperparathyroidy. The differences of clinical and biological symptomatology between these twins suggest individual variations in response to phosphocalcic disorders of the mother. A review of literature find 31 other cases. This study emphasize the aggravation by the mild hypomagnesemia frequently associated, the usual severity of initial clinical symptomatology in contrast with a good neurologic outcome, the diagnosis of maternal hyperparathyroidy.

Adult↗
PubMed1983

A scintigraphic method for the assessment of intraluminal volume and motility of isolated intestinal segments.

The isolated in vivo intestinal segment is a popular experimental preparation for the investigation of intestinal function, but its value has been limited because no method has been available for measuring changes in intraluminal volume under experimental conditions. We report a scintigraphic technique for measuring intraluminal volume and assessing intestinal motility. Between 30 and 180 ml, the volume of a 75-cm segment of canine jejunum, perfused with Tc-99m-labeled tin colloid, was found to be proportional to the recorded count rate. This method has been used to monitor the effects of the hormone vasopressin on intestinal function.

Animals↗
PubMed1981

Retrograde electrical pacing of the small intestine--a new treatment for the short bowel syndrome?

Retrograde electrical pacing has been shown to increase absorption of sodium, glucose and water from a continuously perfused jejunal segment in dogs. Under similar circumstances, absorption of xylose, magnesium, calcium and chloride was also increased by pacing compared with before and after its use (P less than 0.005). Following massive distal small intestinal resection, dogs undergoing post-cibal retrograde pacing showed an increase in body weight (P less than 0.005) and a decrease in faecal fat (P less than 0.005) and nitrogen (P less than 0.01) losses during the test period, compared with similarly prepared dogs who did not undergo pacing. These results suggest that pot-cibal retrograde electrical pacing of the small intestine may have a place in the management of patients with the short bowel syndrome.

Animals↗
PubMed1979

Absorption from the jejunum is increased by forward and backward pacing.

In 4 dogs a 75-cm segment of jejunum was isolated from the intestinal stream. Stimulating electrodes were implanted at each end of the segment and recording electrodes at intervals between. The two ends of the segment were fashioned as stomas on the anterior abdominal wall. After recovery, the electrical activity of the segment was continuously recorded, whilst a solution of 100 mmol/l glucose and 90 mmol/l NaCl was infused into the proximal stoma at 2.9 ml/min. Effluent from the distal stoma was collected in 5-min aliquots for three consecutive 30-min periods. In the second period electrical stimuli were given via either the proximal or the distal bipolar electrodes to entrain pacesetter potentials. Both forward and backward electrical pacing decreased the output of water, glucose and sodium from the jejunal segment, but the decrease was significantly greater with backward pacing. We conclude that pacing a segment of jejunum backwards with electrical stimuli produces a greater increase in absorption from the segment than pacing it forwards, a finding which has therapeutic implications in patients with the short bowel syndrome.

Animals↗
PubMed1979

Prediction of postoperative respiratory complications by simple spirometry.

Spirometry was carried out before and after operation in groups of patients undergoing three preselected surgical procedures. The patterns of impairment of pulmonary function in each group are discussed. Only in patients undergoing inguinal herniorrhaphy was spirometry of value in determining an 'at-risk' group for the development of respiratory complications. Discrimination was optimal on the 1st postoperative day, making it possible for 70% of patients to be discharged from hospital 48 h after this operation with little risk of subsequent respiratory complications.

Forced Expiratory Volume↗
PubMed1978

Increased canine jejunal absorption of water, glucose, and sodium with intestinal pacing.

Our aim was to determine if pacing a segment of jejunum backwards with electrical stimuli could increase absorption from it. In four dogs, 75-cm loops of jejunum were isolated from the intestinal stream. After recovery, fluid was infused into the proximal stoma of the loop and effluent collected from the distal stoma for three consecutive 30-min periods. In the second period electrical stimuli were applied to the distal end of the loop to drive the pacesetter potentials of the loop, hence its contractions, backwards. The output of water, glucose, and sodium from the loop was decreased, and the transit of content through the loop was slowed during backward pacing. We conclude that pacing a segment of jejunum backwards with electrical stimuli enhances absorption of water, glucose, and sodium from that segment.

Animals↗
PubMed1978

Current state of transplantation of the pancreas.

Studies of pancreatic transplantation have been made using the pancreatic tail as an autotransplant model. The endocrine function of the pancreas has been shown to be relatively resistant to warm ischaemic injury. Autotransplantation of the pancreatic tail with a double arterial anastomosis technique can be achieved with 100% immediate success, the graft maintaining satisfactory glucose tolerance and insulin secretion. No important changes in glucose homoeostasis have been shown to result from diversion of pancreatic insulin secretion from portal to systemic veins.

Animals↗
PubMed1977

Carbohydrate tolerance with portal and systemic venous drainage of the pancreas.

Carbohydrate tolerance was studied in 8 dogs with pancreatic venous drainage to the hepatic portal vein and 6 dogs with pancreatic venous drainage to the systemic veins. While systemic venous drainage of the pancreas was associated with higher fasting plasma insulin and lower fasting plasma glucose levels, no significant differences in either glucose clearance or insulin response to glucose were detectable. Therefore, in the maintenance of plasma glucose homeostatis, administration of insulin into the portal vein offers no significant advantages over the easier systemic route.

Amylases↗