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Biomedical subjects

C Simon

Publications and source records attributed to C Simon.

At least 253 records · Page 14Linked to original sources
PubMed1986

Arterial ammonemia changes of renal origin induced in the rat by acid and alkaline diets.

The aim of this study was to investigate the influence of acid and alkali food supplementation on systemic ammonemia to explain the hyperammonemia previously observed in rats fed a high protein diet. In normal rats, arterial ammonia concentration significantly increases after 4 days of HCl-supplemented diet. Following a NaHCO3-enriched food, there is only a slight but not significant decrease in arterial ammonia level. These changes occur before any variation in arterial acid-base status and are of renal origin. Indeed, there is a positive linear correlation (r = 0.946; P less than 0.001) between arterial ammonia level and the ammonia concentration difference between the renal vein and artery (which varies proportionally to the urinary ammonium excretion). Hindquarter uptake and intestinal release of ammonia do not significantly participate in the arterial ammonia changes observed. Following HCl-enriched diets, increased renal glutamine uptake, enhanced hindquarter glutamine release, and perhaps decreased intestinal glutamine uptake occur simultaneously. In conclusion, acid and alkali food supplementation intervenes on the renal ammonia release into the circulation with concomitant arterial ammonemia changes.

Ammonia↗
PubMed1986

Cephalic phase insulin secretion in relation to food presentation in normal and overweight subjects.

The existence of a preabsorptive insulin reflex is well known in animals but remains controversial in humans. Glycemia and insulin variations following olfactive and visual presentation of a standard meal were studied in 25 subjects, 10 of them (5 men and 5 women) of normal weight and 15 overweight (7 men and 8 women), after a 15 hour fast. Blood samples were collected continuously, every minute for 16 minutes after the meal was presented. The presentation produced an early blood insulin increment, variable in magnitude and time course and occurring between the 3rd and 9th minute, in both normal and overweight subjects. Glycemia variations were not significant. Our study demonstrated a positive correlation between the reflex insulin release, body weight and a conscious effort to maintain current body weight. However, the differences between overweight and normal subjects remained small. The physiological and psychological determinants of the cephalic phase of insulin secretion are discussed.

Adult↗
PubMed1986

[CT diagnosis of focal nodular hyperplasia].

The paper analyses the findings of a CT study of 21 lesions of focal nodular hyperplasia in 17 patients. In addition to subjective valuatin of the dynamic studies, densitometric measurements on a time basis were carried out (gamma-fit curves) and a density profile was obtained. These tumour-like lesions show typical density changes with rapid enhancement in the arterial phase and rapid fall in density after one or two minutes. Various patterns of the hyperdense lesions (non-homogeneous, those resembling vessels or homogeneous lesions) may be of significance in differential diagnosis. Atypical density patterns were found particularly in foci projecting from the liver.

Adolescent↗
PubMed1986

[The ultrasensitive determination of TSH permits the prediction of the response to TSH in the TRH test].

A new ultrasensitive TSH immunoradiometric assay (IRMA) using two monoclonal antibodies is now able to distinguish between euthyroid and hyperthyroid patients. The aim of this study was to compare data given by ultrasensitive basal TSH (IRMA) and by the response of TSH to TRH test considered until now as the more reliable test in case of mild or atypical hyperthyroidism. Basal plasma TSH levels were determined in euthyroid (n = 80), hyperthyroid (n = 30), hypothyroid (n = 14) and pituitary deficient patients (n = 8) before and 30 minutes after a TRH test (250 micrograms i.v.). A close linear correlation was found between basal and post-stimulative TSH levels. Normal TSH response ranged from 2 to 22 uU/ml. The sensibility and the specificity of these two parameters appeared comparable in the case of primary dysthyroidism; on the contrary basal TSH levels were not sufficient for the diagnosis of central hypothyroidism. In conclusion, excepted for pituitary deficiency, basal plasma TSH (IRMA) levels are accurate and sufficient in the evaluation of the thyroid function and make the TRH-test useless.

Humans↗
PubMed1986

[Current status of the treatment of nasal septal perforations].

If the most part of the patients with septal perforation have an history of previous surgery, only few of them present symptoms and require surgical repair in spite of the various techniques described in the literature. Bilateral naso-septal mucosal flaps with temporalis fascia interposition graft give the best results. That's why the use of more complicated process remain the exception. Owing to the dubiousness of these reconstructions, it seems advisable to point out the value of preventive actions in order to preserve the nasal physiology.

Humans↗
PubMed1985

[Treatment of severe hyperthyroidism by plasma exchange. Clinical and biological efficacy. 8 cases].

The effectiveness of plasmapheresis was evaluated in 8 patients with severe thyrotoxicosis of diverse origin and clinical manifestations, who underwent a total of 22 plasma exchanges. The method proved rapidly effective in controlling the symptoms in 6 cases. No adverse reaction was noted. In all patients plasma exchanges significantly reduced plasma concentrations of total thyroxine and triiodothyronine and of thyroxine-binding globulin, without effect on free thyroxine and triiodothyronine fractions. The satisfactory clinical results obtained can only be explained by displacement of thyroid hormones from the intracellular compartment. The hormonal variations observed were proportional to the initial hormone concentrations, to the amount of thyroxine-binding globulin removed and to the plasma volume purified. It is concluded that plasmapheresis rapidly extracts thyroid hormones and is therefore useful in the treatment of acute severe thyrotoxicosis.

Adult↗
PubMed1985

4',6-Diamidino-2-phenylindole, a fluorescent probe for tubulin and microtubules.

A new fluorophor for tubulin which has permitted the monitoring of microtubule assembly in vitro is reported. DAPI (4',6-diamidino-2-phenylindole), a fluorophor already known as a DNA intercalator, was shown to bind specifically to a unique tubulin site as a dimer (KD(app) = 43 +/- 5 microM at 37 degrees C) or to tubulin associated in microtubules (KD(app) = 6 +/- 2 microM at 37 degrees C) with the same maximum enhancement in fluorescence. When tubulin polymerization was induced with GTP, the change in DAPI affinity for tubulin resulted in an enhancement of DAPI binding and, consequently, of fluorescence intensity. DAPI, whose binding site is different from that of colchicine, vinblastine, or taxol, did not interfere greatly with microtubule polymerization. It induced a slight diminution of the critical concentration for tubulin assembly due to a decrease in the depolymerizing rate constant. Moreover, DAPI did not interfere with GTP hydrolysis correlated with tubulin polymerization, but it decreased the GTPase activity at the steady state of tubulin assembly. Even at substoichiometric levels DAPI can be used to follow the kinetics of microtubule assembly.

Animals↗
PubMed1985

Autoimmune chronic active hepatitis in postmenopausal women.

We reviewed the clinical and histologic features, course and response to therapy of 18 postmenopausal women with autoimmune chronic active hepatitis (CAH). The presentation of these patients was similar to that of younger patients, except for the lower incidence of associated autoimmune disease. Nuclear antibodies (ANA) were associated with complications, while smooth muscle antibodies (SMA) correlated with an uncomplicated course. Steroid therapy appeared to have less benefit and greater risk in our patients than in studies of all ages. The applicability of results of previous trials demonstrating benefit of corticosteroid therapy for CAH to postmenopausal women is questioned.

Aged↗
PubMed1985

Esophageal motility and symptoms after endoscopic injection sclerotherapy.

Endoscopic injection sclerotherapy is known to cause a variety of motility abnormalities, but the correlation between these changes and symptomatology has not been clearly defined. To assess the effects of endoscopic sclerosis of varices on esophageal function and symptoms, we prospectively studied esophageal motility in 25 patients undergoing sclerotherapy (group I). Thirteen patients underwent studies before and after sclerosis, and 12 patients were studied after completion of therapy. Acid clearance was studied in five patients (group I). Twenty-four of the 25 patients (group I) completed a course of sclerosis without the development of persistent dysphagia. We found that endoscopic sclerotherapy did not significantly alter the velocity of peristalsis or lower esophageal sphincter pressure, amplitude of contraction, or the duration of contraction. Acid clearance was diminished in three of five patients. Four patients who developed an esophageal stricture following sclerotherapy were studied manometrically (group II). Three of these four patients had a manometric pattern characterized by repetitive, nonperistaltic contractions, and all four patients experienced dysphagia which was relieved by bougienage. We conclude that esophageal motility is generally well preserved following endoscopic injection sclerotherapy and does not result in a long-lasting disturbance of swallowing. Dysphagia and disordered esophageal motility do occur after sclerotherapy when a sufficient fibrotic response has resulted in an esophageal stricture.

Esophageal Stenosis↗
PubMed1985

Dysphagia and lower esophageal sphincter abnormalities after proximal gastric vagotomy.

We studied 96 patients subjected to elective proximal gastric vagotomy for intractable duodenal ulceration. Dysphagia was a frequent finding and occurred in 32 percent. It appeared in the immediate postoperative period and usually lasted for 1 to 2 months without any abnormalities in lower esophageal sphincter function. In five patients, dysphagia was severe and, although transient, was associated with changes in lower esophageal function simulating those observed in achalasia. The mechanism of these motor abnormalities is probably due to a reversible neuromuscular dysfunction of the lower esophageal sphincter.

Adult↗