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Biomedical subjects

J Frexinos

Publications and source records attributed to J Frexinos.

At least 109 records · Page 6Linked to original sources
PubMed1981

Experimental study of laser photocoagulation in the treatment of bleeding canine gastric ulcers.

We report experimental results obtained by laser photocoagulation on hemorrhagic lesions induced in dogs. The aims of this study were 1) to evaluate the real efficiency of the YAG laser to ensure hemostasis of briskly bleeding lesions; 2) to determine the minimum energy density necessary to ensure hemostasis; 3) to assess the damage depth inside the gastric wall after photocoagulation; 4) to compare reepithelialization of treated ulcers with that of control ulcers; 5) to evaluate the safety margin for the clinical use of the YAG laser.

Animals↗
PubMed1980

Evaluation of colonic myoelectrical activity in health and functional disorders.

Electrical activity of the colon was investigated in six healthy volunteers and 22 patients presenting functional colonic disorders associated with pain, constipation, or diarrhoea. Myoelectrical activity during 10 hours, including two daily meals, was recorded from eight groups of nickel-chrome electrodes using a 1.5 m length probe introduced by the rectal route. Electromyograms of volunteers consisted of slow waves at two distinct rhythms, approximately 3 and 10 cycles per minute, during 16 to 28% of the recording time respectively for each site. Action potentials were also recorded as 11 to 80 short spike bursts (SSB) per hour lasting 1.5 to 3.5 s at any site and 20-26 long spike bursts (LSB) per hour, lasting 17 to 21 s, occurring in series of four to eight propagated bursts. Additional high-velocity propagated bursts were recorded during the three hour postprandial period. Three typical changes in spike activity patterns were detected: an increase by 170-420% of the number of SSB associated to a high spiking activity was recorded in 13 patients (group I), the absence of SSB, a low spiking activity level and only 3 to 8 LSB per hour (group II), in six patients; and the postprandial response was absent (group III) in three other investigated patients. Evidence for three groups of motor disturbances and their possible relation to clinical manifestations of functional disorders is presented.

Action Potentials↗
PubMed1980

Effects of pancreatic duct ligation on the hamster intestinal mucosa. Histological findings.

After pancreatic duct ligation good correlations were observed between degenerative signs of the exocrine pancreas and ultrastructural changes of intestinal epithelial cells: hypertrophy of Paneth and goblet cells; hyperplasia of Paneth cells, mucous cells and 'intermediate granular cells' after the 10th day. On the 7th day, the absorbing area of the intestine (villi area and microvilli area) decrease significantly. These cytological changes partially disappear after the 15th day concomitant to a partial regeneration of the exocrine pancreas. These findings suggest correlations between the epithelial cells of the small intestine and exocrine pancreatic secretion. Different possibilities (direct action of the pancreatic juice or indirect mechanisms) are discussed and proposed to explain the morphological variations of the intestinal mucosa after pancreatic duct ligation.

Animals↗
PubMed1980

Colonic myoelectrical activity in diarrhea and constipation.

The electrical activity of the colon was recorded during 10 hour sessions from 4 to 8 sets of electrodes carried on a 1.5 m probe in 11 control volunteers and in 35 patients with irritable bowel syndrome manifested by chronic constipation, diarrhea and/or pain. The patterns of electrical spiking activity were compared with that obtained from dogs with induced diarrhea or constipation. In both humans and dogs, two types of electrical activity were identified: short spike bursts (SSB) lasting 0.6 to 2.4 sec and long spike bursts (LSB) lasting 6.4 to 25 sec. The SSBs occurred at a maximum frequency of 13 per min. in man, while the LSB never exceeded 3 per min. Characteristic changes in the myoelectrical activity mainly coincided with disorders. In a group I containing 19 patients, most of them exhibiting constipation, the level of activity was 62% higher than in healthy subjects with an increase in the SSB hourly frequency of 170 to 420%. The colonic activity was similarly increased in constipated dogs. In a group II containing 11 patients suffering from soft feces or watery diarrhea, the LSB activity was significantly reduced. In a group III containing 5 patients, diffuse abdominal pain occurred after eating despite a reduction of the electromotor feeding responses and the absence of colonic postprandial rushes. The results indicate that the functional colonic disorders in man corresponded mainly to 3 specific patterns of myoelectrical activity, one of them (Group I) being reproduced in experimentally constipated dogs.

Action Potentials↗
PubMed1980

Screening for colorectal tumors - results of two years experience.

The experience after two years of systematic colorectal tumors screening of 603 subjects, aged between 40 and 70, is reported. All subjects were submitted to proctoscopy (P) and air filled barium enema (AFBE). Total frequency of screened tumors: 15.25%. More than 85% of the tumors were found in the recto-sigmoid. Two subgroups were identified in this population. In subgroup A, 125 subjects were submitted to P, AFBE and flexible pansigmoidoscopy (FP). Percentage of screened tumors is 19.2%. Sensitivity rate of radiology for exploration of the recto-sigmoid area, as compared to FP is rather low: 0.41. In subgroup B, 165 subjects were submitted to hemoccult, P, AFBE and colonoscopy when an abnormal or dubious image was shown by AFBE. The comparative study of these different means of investigation shows a very low rate of sensitivity of hemoccult: 0.16. In addition, the percentage of screened colorectal tumors is significantly higher (p less than 0.01) in subjects with personal or family history of polyp or carcinoma: 22%, compared to the incidence in the remaining population of 13%. Flexible pansigmoidoscopy is recommended for systematic screening of colorectal tumors in subjects older than 40.

Adult↗
PubMed1979

A cyto-physiological study of the G-cell secretory cycle in the antrum mucosa of the hamster and of the rat.

The secretory cycle of the antral G cell in the golden hamster and in the Wistar rat has been investigated, using classical techniques of optical and electron microscopy associated with special methods (such as goniometry, densitometry, immunohistology, morphometry) and with radioimmunoassay for gastrin. This paper confirms the secretory cycle of the G cell after refeeding. It clarifies the nature of granule polymorphism and suggests a particular mechanism of emiocytosis with sequential granule fusion. Furthermore, our investigations show some dissociations between the G cell, the parietal cycle, and the seric immunoreactive gastrin in the late phase of the secretory cycle (2 to 6 h after refeeding).

Animals↗