Biomedical subjects
Publications and source records attributed to M Fabre.
Evidence from a case studied with electron microscopy suggests that tumors diagnosed up till now as Garre's neurinoma (glandular schwannoma), without ultrastructural proof, may not in fact originate in Schwann cells. None of the characteristics of Schwann cells could be demonstrated in the fusiform cells of the tumor. The medical literature is reviewed.
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Five patients with typical seropositive rheumatoid arthritis were treated by plasma exchange. All patients had severe affections resistant to conventional treatment, while in four cases the disease involved extra-articular localizations: rheumatoid nodules (3 cases), polyneuritis (1 case), skin necrosis (1 case). Each patient received between 5 and 10 plasma exchanges over a period of 3 to 4 weeks. No major complications were observed. Immediate results were very good in all cases, as shown by absence of clinical expression of the arthritis, marked regression in extra-articular symptoms, and reduction in erythrocyte sedimentation rate without parallel alterations in rheumatoid factor levels. Improvement lasted for only a few weeks in 3 patients, in one case preceded by an acutely painful episode. In the remaining 2 cases, with associated vasculitis, improvement has been sustained for a period that now exceeds one year. Results are compared with those reported in the published literature, and the mode of action and indications for plasma exchange in rheumatoid arthritis discussed.
The effect of the chronic cutaneous application of iodine-containing substances on the thyroid function was studied in the guinea-pig. Six iodinated products were daily applied at the rate of 2 g/kg/day for 90 days. We find a quasi-abolition in the thyroid 131I-uptake (reflecting the transcutaneous absorption of free iodine) and an important transient thyroidal hyperproduction during the first month. Then, this primary hyperthyroidism induces a strong pituitary negative feed-back so that the levels of the circulating hormones T3 and T4 are normalized at the end of the experiment; a new hormonal balance is reached with a TSH level reduced by half compared to its normal value.
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Seven cats were trained to press a lever that moved in front of them at an adjustable speed and at random from left to right or from right to left. Efficient presses were reinforced by food. After measuring accuracy and latency of pressing the lever, the animals underwent bilateral ablation of the suprasylvian (SS) cortex; in three animals the lesions involved its anterior aspect; in two animals, they were restricted to its middle portion; two other cats had lesions of both anterior and the middle SS cortex. No long-lasting postoperative deficits were observed in any group when the lever remained immobile. On the other hand, the scores after anterior SS lesions were severely deteriorated, when presses had to be performed on the moving lever. No such deficits were noticed when the ablations were restricted to the middle SS. These results suggest that the cat anterior suprasylvian cortex (that includes parts of areas 5 and 7) plays a determinant role in the spatial adjustment of a visually guided (or visually triggered) forelimb movement.
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Cats were trained to press on a lever either fixed or moving at different speeds from left to right or right to left at random. In the first series of animals, the following bilateral lesions were performed after reaching criterion on the moving lever: (1) deep cutting of cortico-cortical fibers connecting visual and frontal cortex; (2) subtotal electrolytic destruction of n. ventralis lateralis of the thalamus (nVL); (3) ablation of the anterior (3a) or middle (3b) suprasylvian cortex. No postoperative deficits were noticed after lesions (1), (2), (1 + 2) or (3b). On the other hand, impairment was found after lesion (3a), strongly suggesting the role of the anterior suprasylvian cortex in visual guidance of the forepaw movement in cat. The second group of animals was first trained to press the fixed lever and then underwent bilateral n. VL lesions. After lesion, performance with fixed lever remained normal while the animals displayed a deficit with the moving lever. The conclusion is that the n. VL is essential only during the acquisition phase of the tested visuomotor performance.
Bilatéral lesions of the thalamic nucleus ventralis lateralis were performed in cats, either after [1] or before [2] training to reach a moving target with the forepaw. In situation [1], lesions were ineffective; in situation [2] the animal never reached normal scores. VL thus seems to be essential only in the acquisition phase of the tested visuomotor performance.
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As LH is capable of stimulating ovarian progesterone secretion at the beginning of 4-day cycles, it was the aim of this work to determine whether corpora lutea formed at the end of a preceding cycle are responsible for the increase in ovarian progesterone secretion. 4-day cyclic female rats were injected with LH on dioestrus I at 8...9 a.m. (64 microgram/100 g/b.w. expressed in terms of NIH-LH-S3). An increase in the peripheral blood progesterone concentration was shown to occur on the morning of dioestrus II in LH-treated females when compared to control females. Concomitantly enlarged mitochondria, numerous membranes of the smooth endoplasmic reticulum and a decrease in the number of lipid droplets were observed in LH-treated females. Inversely signs of involution of the corpora lutea were noted from the morning of dioestrus I to that of dioestrus II in noninjected females. It is concluded that LH-induced progesterone increase at dioestrus II results from the activation of the corpora lutea formed at the end of the preceding cycle.
Pre- and postoperative specimens of ileal loops used in transileal ureteroplasty have been taken and ultrastructural modifications concerning the intestinal mucosa with special attention to the epithelial cells are described. The enterocytes undergo significant modifications because of the operation (i.e. collapse of striated border and entrancement of lysosomal inclusions). Contact with the urine brings about osmotic changes of the intestinal epithelium as well as irritation of the capillar endothelium. But most structural modifications observed histologically or by electron microscopy seem to be reversible. 6 months after the operation the histological structure of the ileum in contact with urine again becomes morphologically normal.
Acute intoxication by diethylene glycol (LD 50) in male rats is associated with a severe metabolic acidosis which is significantly decreased by intraperitoneal (IP) hydration or IP alkalinization and eliminated by IP ethanol. Tubular necrosis and deposit of calcium oxalate crkystals constitute the histological renal lesions in 50% of rats given diethylene glycol with or without IP hydration. Groups with massive IP alkalinization and/or IP ethanol do not present any renal lesion. It could be inferred that diethylene glycol has the same metabolic pathway as ethylene glycol and the treatment of acute intoxication by diethylene glycol should be the same as that of acute poisoning by ethylene glycol.
Epithelial-mesenchyme interactions during mouse molar tooth morphogenesis were observed by electron microscopy. The basal lamina was intact from day 10 to day 18. Aperiodic, later also periodic fibrils were deposited on the basal lamina. Ectomesenchymal cell processes were always in close relation with the basal lamina or with the fibrillar material. On day 19 some direct heterotypic cell contacts between odontoblasts and preameloblasts were observed. At all stages, especially the preodontoblasts but also preameloblasts, gave rise to aggregated vesicles, which were extruded in the epithelial-mesenchymal space.
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