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Biomedical subjects

M Nicaise

Publications and source records attributed to M Nicaise.

8 recordsLinked to original sources
PubMed1996

Protection by glutathione against the antiproliferative effects of nitric oxide. Dependence on kinetics of no release.

Pretreatment by L-buthionine sulfoximine (BSO), which inactivates gamma-glutamylcysteine synthetase and, therefore, inhibits glutathione (GSH) synthesis, greatly increased the sensitivity of tumor cells to the antiproliferative effects of several NO-donating compounds. The sensitization that resulted from depletion of cellular GSH pools was observed in tumor cells exhibiting different degrees of resistance to NO. In contrast, GSH depletion of tumor target cells did not affect their sensitivity to the cytostatic activity of activated macrophages and other NO-producing cells (EMT6 cells treated by interferon gamma and LPS). The kinetics for NO generation is a parameter that may differentiate NO-producing cells and short-lived NO donors. To study the relationship between the magnitude of NO fluxes and the increased toxicity on BSO-pretreated cells, two NO-releasing zwitterions derived from polyamines (NONOates) with different half-lives were selected. NO fluxes as a function of time were simulated, according to the donor half-life and initial concentration, and antiproliferative effects on control and BSO-treated cells were compared. GSH depletion increased the sensitivity of tumor cells in the case of the less stable NO donor only. We, thus, propose that intracellular GSH is specifically protective against high fluxes of NO.

Animals↗
PubMed1991

Morphological study of the development of the disseminate prostate in intact and castrated male pigs aged two to six months.

The light-microscopical and ultrastructural differentiation of the disseminate prostate was studied in 12 boars and 8 barrows, ranging in age from 8 to 28 and 12 to 27 weeks, respectively. The barrows had been castrated at the age of 8 weeks. In young boars the prostate is organized in an inner zone and an outer zone. The glandular tubules of the latter are more differentiated than those in the inner zone. Sexual maturation in the prostate is characterized by almost complete reduction of the inner zone and concomitant enlargement of the outer zone. This differentiation of the inner zone occurs progressively and is manifested by a higher density of the glandular tubules, by a decrease in the number of basal cells and by an increase in the secretory tubular cells containing more microvilli, organelles and secretory vesicles. A few weeks after castration, the characteristic morphology of the undifferentiated inner zone is found throughout the entire glandular layer. The number of glandular tubules in barrows has decreased, and their cells show minimal secretory activity, nuclear indentations and a decrease in their organelles. A further castration effect is vacuolization of the perinuclear cytoplasm in numerous glandular cells.

Animals↗
PubMed1984

Delayed neuropathy by the organophosphorus nerve agents soman and tabun.

The organophosphorus nerve agents soman and tabun were tested in the hen at doses 120-150 times higher than their acute LD50, as it was assumed that these doses would produce delayed neuropathy. The animals were protected against the acute lethal effect of these agents by pretreatment with atropine, physostigmine, diazepam, and the oxime HI-6 or obidoxime. The surviving animals were followed for 30 days and the occurrence of delayed neuropathy was clinically diagnosed. Soman produced severe delayed neuropathy at a dose of 1.5 mg/kg, a dose which produced acute lethality in five animals out of six. Tabun elicited very mild neuropathic symptoms in one animal out of two at a dose of 6 mg/kg given on 2 consecutive days. Delayed neuropathy was not seen in the hens that survived the acute toxicity of a single dose of tabun , 12 mg/kg (three out of six) or 15 mg/kg (two out of six).

Animals↗
PubMed1984

A simple and inexpensive device for applying a calibration pulse when performing intracellular recording.

A simple and low-cost device is described which facilitates the calibration of intracellular DC recordings in amplitude and time. A current source, optically coupled to a conventional stimulator, injects a pulse of current, across a 1-omega resistor connecting the preparation to ground. Amplitude and duration of the current pulse are determined by adjusting the voltage output of the conventional stimulator. By linking the preparation to ground through a resistor of 1 omega the background noise and the DC shifts in the voltage trace of the intracellular recording are kept to a minimum.

Animals↗
PubMed1981

Structure of the prostate and the pelvic urethra in barrows and the changes induced by diethylstilbestrol.

The anatomical and light microscopical structures of the pelvic urethra with the surrounding prostate were investigated in male pigs, which were castrated early in life and examined at slaughter weight. The general structure was regular in the caudal part, but was irregular in the cranial part. In the prostate each lobule contained a cell-rich stroma, which surrounded several glandular tubules and a few prostate ductules. The tubules were lined by low columnar cells and some reserve cells, the ductules by a low two-layered epithelium and the urethra by a transitional epithelium. Small differences in the gland structure and urethral epithelium were observed between the cranial and caudal part. Subcutaneous injection of diethylstilbestrol provoked metaplasia of the epithelium of the urethra and the ducts, while the peroral administration of diethylstilbestrol in combination with methyltestosterone resulted in an increased number of glandular tubules.

Animals↗
PubMed1976

Bone in dermatosparaxis. I. Morphologic analysis.

Normal (N-) calf bone consists of lamellae regularly spaced and oriented parallel to the periosteum. The lamellae increase in thickness from the periosteum to the medullary cavity, by apposition of layers of cells and a calcifying matrix on either side of a hypercalcified primer. In the dermatosparactic (D-) bone, the hypercalcified primer is barely visible and the cells are irregularly arranged within the lamellae. The poorly defined vascular spaces are partly filled with an acellular calcified material. In the D-bone, the collagen fibers are sparse and radiate from the vascular space, while in the N-bone they are abundant and laid down concentric with the blood channels. In the D-bone, only a few weeks old, the outer lamellae are radially oriented with respect to the medullar cavity, while haversian remodeling already occurs in the inner part of the diaphysis. At 6 months, the inner half of the diaphysis is made up of normal haversian secondary bone, while the outer half is made up of radial lamellae. The alteration of the mechanical properties of procollagen fibers in the D-bone might be responsible for its defective organization. A resistant fibrous framework, therefore, seems required to ensure the spatial organization of the cells in the calcifying matrix and to maintain its cohesion.

Age Factors↗