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Biomedical subjects

M Delvaux

Publications and source records attributed to M Delvaux.

101 records · Page 6Linked to original sources

Distinct activation of Na+-H+ exchange by gastrin and CCK peptide in acini from guinea pig.

The effect of cholecystokinin (CCK)-gastrin family peptides (caerulein, unsulfated gastrin-17, and pentagastrin) and secretin in activating amiloride-sensitive 22Na uptake were investigated in guinea pig pancreatic acini. Secretin had no effect, but CCK-gastrin peptides stimulated the amiloride-sensitive 22Na uptake. The effect of caerulein was inhibited by dibutyryl guanosine 3',5'-cyclic monophosphate (cGMP) and asperlicin, indicating that activation of the Na+-H+ antiport caused by caerulein is mediated by CCK receptors. The effect of gastrin was dibutyryl cGMP and asperlicin insensitive, whereas the effect of pentagastrin was inhibited by the CCK antagonists but with a low affinity, indicating that the effect of gastrin and that of pentagastrin was CCK receptor independent. The calcium ionophore A23187 caused an increase in amiloride-sensitive 22Na uptake. However, the effect of caerulein, which increased internal calcium concentration, was not modified after depletion of intracellular calcium, and that of CCK-gastrin family peptides was not dependent on external calcium concentration. Activation of amiloride-sensitive 22Na uptake was also induced by 12-O-tetradecanoylphorbol 13-acetate and 1-oleoyl-2-acetyl-glycerol. Activation of protein kinase c may be involved in the mechanism of caerulein or gastrin in activating the Na+-H+ exchange.

Amiloride↗

[Treatment of rectal cancer with the neodymium-YAG laser].

Fifty-two non-surgical patients presenting rectal carcinoma were treated initially with palliative laser Nd-YAG. Their mean age was 79 years (49-92). Thirty patients had a severe diarrheic syndrome, associated with tenesmus in 27 cases; 20 patients had repeated hematochezia (5 presenting diarrhea as well); 6 had obstructive signs and one was symptom-free. Thirty lesions were less than 6 cm in size, 12 were between 7 and 10 cm and 10 were greater than 10 cm. Twenty-two lesions were circumferential. During the study period, 444 laser sessions were performed (mean 8.5/patient). Bleeding was stopped in all cases during the first session. Improvement of the diarrheic syndrome, obtained in 24 of the 30 patients, was correlated with the reduction of tumor volume. Tenesmus disappeared after 1 or 2 sessions, regardless of whether the tumor was destroyed or not. Failure was observed in 6 patients with lesions larger than 10 cm. Colostomy was avoided in 4 of the 6 obstructed patients. Negative biopsies were repeatedly obtained after mucosal repair in 9 patients with small lesions (less than 6 cm). Mean follow-up is now 8.2 months for the patients still alive. Complications were: 2 cicatricial stenosis and 3 hemorrhages (one required blood transfusion). Laser Nd-YAG allows palliative but conservative and effective treatment for rectal cancers. Although complete destruction is possible for small lesions, indications with curative intent are currently limited to patients with major contraindications to surgery.

Adenocarcinoma↗

[Yag laser photocoagulation and monopolar electrohydrocoagulation: randomized study of the hemostatic effect on experimental hemorrhagic ulcer in dogs].

The purpose of this randomized study was to compare the effects of two methods of hemostasis--photocoagulation using YAG Neodyme laser and liquid monopolar electrocoagulation--on acute experimental bleeding ulcers created in the dog stomach with an ulcer-maker. One hundred and fifty-three lesions were made and randomized into 3 groups; 51 lesions were treated with photocoagulation and complete hemostasis was achieved in all cases. Hemostasis was obtained in 80 p. 100 of 51 ulcers treated with liquid electrocoagulation. Control untreated ulcers remained hemorrhagic after 45 min of observation. The mean external muscle injury on day 7 was 55 p. 100 after photocoagulation and 65 p. 100 after liquid electrocoagulation. On day 14, mean external injury was 60 p. 100 after photocoagulation and 75 p. 100 after liquid electrocoagulation (non-significant difference). On day 7, the mean re-epithelization index, expressed as the percentage of the original ulcer diameter, ranged from 8 to 10 p. 100 in each trial group. On day 14, reepithelization covered 78 p. 100 of control ulcers and 72 p. 100 of photocoagulated ulcers (NS). This percentage falls to 47 p. 100 in ulcers treated with liquid electrocoagulation (p less than 0.01 when compared with ulcers treated with photocoagulation). Photocoagulation seemed to be more efficient in ensuring hemostasis and external muscle injury was correlated with the energy delivered. External muscle injury could not be controlled by liquid electrocoagulation. However the difference in the percentages of mean external muscle injury between the two methods was not significant. Therefore, in man, the risk of perforation is certainly slight and not very different whatever the method of hemostasis considered.

Animals↗

Trimebutine: mechanism of action, effects on gastrointestinal function and clinical results.

The actions of trimebutine [3,4,5-trimethoxybenzoic acid 2-(dimethylamino)-2-phenylbutylester] on the gastrointestinal tract are mediated via (i) an agonist effect on peripheral mu, kappa and delta opiate receptors and (ii) release of gastrointestinal peptides such as motilin and modulation of the release of other peptides, including vasoactive intestinal peptide, gastrin and glucagon. Trimebutine accelerates gastric emptying, induces premature phase III of the migrating motor complex in the intestine and modulates the contractile activity of the colon. Recently, trimebutine has also been shown to decrease reflexes induced by distension of the gut lumen in animals and it may therefore modulate visceral sensitivity. Clinically, trimebutine has proved to be effective in the treatment of both acute and chronic abdominal pain in patients with functional bowel disorders, especially irritable bowel syndrome, at doses ranging from 300 to 600 mg/day. It is also effective in children presenting with abdominal pain.

Abdominal Pain↗

[Functional pancreatic studies in the diagnosis and treatment of chronic pancreatitis].

The diagnosis of chronic pancreatitis is usually established by clinical history and morphological criteria based on radiological and/or endoscopic (ERCP) findings. When these morphological signs are absent or equivocal, pancreatic function testing is necessary. Direct testing by duodenal intubation with hormonal stimulation is still considered as the reference method ("gold standard"). Numerous indirect tests have been introduced to replace the duodenal intubation which is rarely well accepted and difficult to repeat. Moreover this technique is only available in highly specialized centres. Among the tubeless tests, the Paba test and the pancreolauryl test are gaining interest. Several modifications of these tests have improved their sensitivity and specificity. In most instances, these tests are unable to detect mild pancreatic insufficiency. However their reproducibility in individual cases could be useful for the follow-up of patients with proven pancreatic insufficiency, particularly with regard to the efficacy and the compliance of replacement therapy.

Chronic Disease↗