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Biomedical subjects

F Meunier

Publications and source records attributed to F Meunier.

122 records · Page 7Linked to original sources
PubMed1979

Rapid acetylcholine and adenosine triphosphate oscillations triggered by stimulation of the Torpedo electric organ.

1. When the electric organ of Torpedo is stimulated a large number of synchronized cholinergic synapses are activated. This permits the measurement of changes in the tissue level of ACh associated with the release process, usually recorded as an electric discharge. 2. At 5 Hz stimulation the output per impulse and the amount of cytoplasmic (free ACh) declines for about 30 s. The output then remains constant while ACh is synthesized for about 90 s. Finally, the output and cytoplasmic ACh are exhausted after 120 s. These 'slow wave' changes in ACh represent about 50% of the total. 3. Superimposed on the 'slow wave' are rapid oscillations of 5 s period, which represent about 30% of the total ACh. 4. The amount of ATP oscillates in phase with ACh. These oscillations might result from regulation of enzymes involved in the synthesis of transmitter. 5. The amplitude of electrical discharge does not normally oscillate. Transmitter output is therefore not directly related to ACh concentration changes. The mechanism releasing ACh is a saturable process.

Acetylcholine↗
PubMed1975

[Therapeutic action of coagulation factor XIII in scleroderma. 20 cases].

Clotting factor XIII was used in 13 patients suffering from scleroderma, 17 with generalised scleroderma and 3 with localised scleroderma. The duration of treatment varied between 15 days and 6 months. The effect was marked in 7 cases and more moderate in 5 others. It took the form of increased suppleness of the skin, improved joint mobility and, to a lesser degree, an improvement in vasomotor disturbances of the extremities. Oesophageal abnormalities on X-ray were never altered. The return to normal of alveolar-capillary diffusion seen in two cases requires futher confirmation. The action of factor XIII in scleroderma may be explicable by the formation of transamidation bonds between the alpha chains of the collagen molecule, similar to those obtained on fibrin.

Adolescent↗
PubMedDate not supplied

Morphological priming effect: the role of surface frequency.

Two cross-modal experiments were conducted to investigate the format of lexical representation of suffixed derived words and their stems. The results show that only low frequency suffixed words (as opposed to high frequency suffixed words) yield a full priming effect of their stems. By contrast, a stem (e.g., travail) does not fully prime words belonging to the same morphological family (e.g., travailleur), although it primes high frequency suffixed words more than it does low frequency words. To account for these findings we propose a model in which the stem and high frequency affixed words are represented both as full forms and as decomposed morphemes while low frequency affixed words are represented only in a decomposed form.

Analysis of Variance↗
PubMedDate not supplied

New methods for delivery of antifungal agents.

Amphotericin B remains the drug of choice for many invasive fungal infections. However, failures of therapy, relapses, and adverse effects are numerous. New modalities of antifungal therapy are extensively evaluated, including various preparations of liposomal amphotericin B and promising new agents such as itraconazole and fluconazole. Numerous studies indicate the potential benefit of liposomal amphotericin B. In particular, a dramatic decrease in the incidence of immediate adverse effects as compared with the incidence with amphotericin B complexed with deoxycholate has been documented. In addition, a prolonged in vitro antifungal activity has been observed with unilamellar liposomes. As yet there is no standardized commercially available preparation of liposomal amphotericin B. Extensive research in this field is in progress. Large comparative studies for the evaluation of the clinical efficacy of these preparations are planned. Intranasal administration of amphotericin B seems useful for the prevention of aspergillosis in predisposed patients. These various approaches should improve the management and prognosis of fungal infections.

Administration, Intranasal↗
PubMedDate not supplied

Therapy for oropharyngeal candidiasis in the immunocompromised host: a randomized double-blind study of fluconazole vs. ketoconazole.

Optimal therapy for oropharyngeal candidiasis, a common infection in immunocompromised patients, has yet to be clearly defined. Topical therapy is usually poorly tolerated; ketoconazole is effective but absorption is highly variable. New antifungal agents have been developed to increase the therapeutic options. Fluconazole is active against yeasts, is available in both oral and intravenous formulations, and has a pharmacokinetic profile different from that of ketoconazole. This randomized double-blind study evaluates systemic antifungal therapy with fluconazole (100 mg daily) or ketoconazole (400-mg daily) for oropharyngeal candidiasis in patients with cancer. Clinical cure was observed in 15 of 19 and 14 of 18 patients treated with fluconazole and ketoconazole, respectively. Eradication of pathogenic yeasts ws documented for 10 patients in both groups. The rates of relapse were similar, but relapse occurred earlier in patients in the ketoconazole group. Overall, this study demonstrates the value of a dosage of 100 mg of fluconazole or of 400 mg of ketoconazole daily for the management of oropharyngeal candidiasis in patients with cancer.

Agranulocytosis↗
PubMedDate not supplied

Prevention and mycoses in immunocompromised patients.

Invasive fungal infections remain a major complication in immunocompromised hosts. The prognosis in these infections is poor, particularly for neutropenic patients with cancer. Candidiasis and aspergillosis are common in these patients, and numerous attempts have been made to evaluate potential prophylactic methods. Despite the fact that various agents (polyenes and/or imidazoles) and various formulations have been tested, the reported data on their effectiveness are still controversial. No single regimen can be recommended at this time for prevention of invasive candidiasis. The potential emergence of fungal strains resistant to the polyenes and the selection of Torulopsis glabrata by the imidazoles should also be taken into consideration. Aspergillosis, which is an airborne infection, may be prevented by isolation of patients at risk in rooms equipped with high-efficiency particulate air (HEPA) filters. In addition, the prophylactic administration of nasal sprays of amphotericin B has shown encouraging results, and this approach should be further investigated.

Administration, Topical↗
PubMedDate not supplied

[Prevention using pefloxacin of infections in cancer patients with granulocytopenia].

The practical procedures of digestive tract decontamination and prophylaxis of bacterial infection in granulocytopenic patients are debated. Fluoroquinolones are active against Gram-negative bacilli and have few side-effects. Pefloxacin was administered prophylactically to patients with cancer and granulocytopenia. None of them developed Gram-negative septicaemia, but 2 cases of streptococcal septicaemia were observed. The drug was well tolerated by all patients except one. Studies are currently in progress to try to reduce the incidence of septicaemia caused by Gram-positive cocci, using pefloxacin combined with penicillin.

Agranulocytosis↗
PubMedDate not supplied

In vivo and in vitro glucuronidation of the flavonoid diosmetin in rats.

Flavonoids form an important family of compounds widely present in plants and therefore in food, sometimes as substitutes for synthetic antioxidants. Although the excretion routes of flavonoids in animals has been explored, little is known about the details of their conjugation in the xenobiotic metabolism pathway. In this study, we investigate the metabolism of diosmetin as a model compound in the rat, particularly its level in blood after treatment (100 mg/kg, po) and the presence of its glucuronide(s) in both blood and urine. We demonstrate that after po treatment of the rat, a rapid glucuronidation takes place and that diosmetin circulates as glucuronides, whereas no free diosmetin is present in blood and urine. The glucuronides formed are present in the blood plasma at a high level (approximately 10 micrograms/ml), for at least 6 hr after the treatment and the conjugates are excreted in urine. We have detected four different glucuronides in blood and characterized the two major ones after purification by a combination of MS, NMR, and UV spectroscopy: diosmetin-7,3'-diglucuronide and diosmetin-3'-glucuronide. A brief characterization of the in vitro glucuronidation of some flavonoid compounds using liver microsomal preparations suggests that this important class of natural compounds might be conjugated by a specific isoform of UDP-glucuronosyltransferase. Thus, this work brings evidence that diosmetin is rapidly glucuronoconjugated in the rat and provides an explanation for the low po bioavailability of the unchanged compound that can be generalized to this important class of natural compounds.

Animals↗