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Eleven biopsies of bone regenerate during bone lengthening following the Ilizarov technique were studied. They concerned 10 patients with a mean age of 13.5 years. The length of the biopsied regenerate was between 14 and 90 mm, and the delay after the initial procedure was 23 to 502 days. The aim of this study was to get informations on the histology of the regenerate, to quantify osseous data and to propose a surgical strategy. These data were obtained by analyze of non decalcified bone, biopsies were included in a methylmetacrylate block. Measure of the mineralisation speed was determined after a double intake of tetracycline. The bony trabeculations were formed very early, as soon as the third week. They were placed like a thread, that means in an anastomotic system which can quickly become resistant. But is was necessary to keep a lengthening speed under 1 mm per day 0.7 to 0.8 mm per day seems to be the best speed in adolescents. The ossification was of membranous type, without cartilaginous stage. Osteoblastic and osteoclastic activities were extremely rich, even after one year or after the bone healing. The main point was the maturity of the regenerate acquired as soon as the 4th month.

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We have studied liver biopsies obtained in 12 hyperlipoproteinemic (HLP) patients (type II, 6; type IV, 6) treated with diet and fenofibrate, and in 15 patients (type II, 11; type IV, 4) receiving diet only. Electron microscopy of liver biopsies and the morphometric analysis according to the method of Weibel and Rohr showed mitrochondrial changes in patients treated with fenofibrate, these changes depending on the type of hyperlipoproteinemia. In type II HLP, we found a decreased volume of normal mitochondria (fenofibrate, 125.72 +/- 17.04 X 10(-3) cm3/cm3; diet only, 185.84 +/- 8.96 10(-3), P less than .05). In type IV HLP we found a decreased number of giant mitochondria (fenofibrate, 0.08 +/- 0.03 X 10(10) cm-3; diet only, 0.32 +/- 0.08 X 10(10) cm-3, P less than .05) and a decreased volume of altered mitochondria (fenofibrate, 6.00 +/- 1.44 X 10(-3) cm3/cm3; diet only, 13.61 +/- 1.17 X 10(-3), P less than .05). In contrast with the rodent studies, the present study shows no change in the number of volume of peroxisomes.

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A morphometric study on liver biopsies from patients with primary hyperlipoproteinemia (IIa n = 4, IIb n = 7, IV n = 7) and in controls (n = 7) was performed by light and electron microscopy. We found hypertrophy of peroxisomes in all subjects with hyperlipoproteinemia. As none of our patients had been given lipid-lowering drugs, this increase in volume seems to be due to hyperlipoproteinemia. Hypertrophy of peroxisomes in hyperlipoproteinemia may constitute a response of the hepatocyte to a disturbed metabolic state. Alterations of peroxisomes in hyperlipoproteinemia may thus occur prior to any lipid-lowering therapy.

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We obtained liver biopsies in 4 patients with type IIA and 7 patients with type IIB hyperlipoproteinemia, and also in 7 healthy controls. A morphometric analysis of liver tissue was carried out by light and electron microscopy. Structural alterations of the hepatocyte and its organelles in type IIA and IIB hyperlipoproteinemia seem to fall into different categories: smaller nuclei, enlarged peroxisomes and altered mitochondria are found in both types of hyperlipoproteinemia, while an increase in the volume of hepatocytes is found only in type IIA. The enlargement of liver peroxisomes in untreated hyperlipoproteinemia is noteworthy, since it has been considered as a marker of the liver toxicity of lipid-lowering drugs.

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An experimental animal model of a vascularized graft is presented as an alternative to recover faster function. The technique is described and the model compared to a conventional graft in the sciatic nerve of a rabbit. Results are evaluated with histological studies and quantified using a computer to measure the thickness of the myelin sheath as a correspondence factor of regeneration. Results showed a more favorable regeneration when a vascularized graft was used.

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In rodents fenofibrate shares with other triglyceride-lowering agents the potential to increase the liver peroxisome population. It was therefore of interest to look for this effect in hyperlipoproteinemic patients receiving this drug. Light and electron microscopy of liver biopsies from a group of 10 patients treated with fenofibrate and from another group of 13 receiving diet only, show no morphological difference between both groups. In contrast with the rodent data the morphometric study reveals no significant changes in the number (fenofibrate group: 7.96 10(10) cm-3; group receiving diet alone: 8.41 10(10) peroxisomes per cm3 of liver tissue) or in the size (fenofibrate group: diameter = 0.53 +/- 0.07 micron; group receiving diet alone: 0.50 +/- 0.06) of peroxisomes. The difference between our results and those obtained consistently in rodents may be due to the relatively low dose in man and/or a species-dependant difference in enzyme content of liver peroxisomes, itself related to an apparent difference in the way in which lipids are handled.

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Seminiferous tubules from 5 day-old rats maintained in a semi-solid culture system were examined for 4, 8 or 12 days. Morphometric and ultrastructural studies show a significant increase in the seminiferous tubule diameter and normal Sertoli cell differentiation. All the germinal cells degenerate except the spermatogonia.

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In rodents fenofibrate shares with other triglyceride-lowering agents the potential to increase the liver peroxisome population. It was therefore of interest to look for this effect in hyperlipoproteinemic patients receiving this drug. Light and electron microscopy of liver biopsies from a group of 10 patients treated with fenofibrate and from another group of 15 receiving diet only, show no morphological difference between both groups. In contrast with the rodent data the morphometric study reveals no significant changes in the number (fenofibrate group: 7.96 10(10) cm-3; group receiving diet alone: 8.41 10(10) peroxisomes/cm3 of liver tissue) or in the size (fenofibrate group: Diameter = 0.53 +/- 0.07 micrometer--group receiving diet alone: 0.50 +/- 0.06) of peroxisomes. The difference between our results and those obtained consistently in rodents may be due to the relatively low dose in man and/or a species-dependent difference in enzyme content of liver peroxisomes, itself related to an apparent difference in the way in which lipids are handled.

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The pores of Kohn are apertures in the alveolar septum, which allow the communication of two adjacent alveoli. Their existence has been most disputed, but was lastly supported in man and adult mammalians by observations from electron microscopy. Located between the meshes of the capillary network, these alveolar apertures are circular or oval, and are bordered by extensions of type I pneumocytes. Type II pneumocytes are often located close to the pores of Kohn. The presence of two near apertures gives a "double-barrelled gun" aspect, frequently observed in the old animal. The specific connections of the pore of Kohn with the septal components, particularly by the myofibroblasts, are analysed. The quantification of the pores of Kohn in various species shows great variations according to the fixation technique, animals age and site of alveoli in the lung and the lobules. The size of these apertures also depends on species, varying from 0.8 to 15 micrograms. Histogenesis of these apertures is still poorly understood and various processes can be evoked. Ventilation, which differs according to the site of the alveoli in the lung, is a determinant factor, proved by the great number of pores of Kohn in the hyperventilated areas. The role of the macrophages (synthesis and excretion of proteases and lipases) is also discussed. The formation of pores of Kohn is linked with renewing and dehiscence of alveolar epithelial cells. The role of alveolar pores in collateral ventilation seems relatively weak in the physiological state, whereas it is certain in lung pathology, contributing to the propagation of bacterial infections in the adult and to changes of local ventilatory conditions in atelectasis and asthmatic bronchoconstriction. The alveolar apertures can explain the specific propagation of some epitheliotropical peripheral cancers (bronchiolo-alveolar carcinoma). The pore of Kohn is one of the first signs of parenchymatous senescence of the pulmonary alveolus; its part in the appearance and extension of emphysematous disorders is also discussed.

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The effects of grafting segments of femoral vein in the dog have been studied. The venous segments, either reversed or left in situ, were interposed in the course of the femoral artery; these 'arterialized grafts' were compared with a segment of vein grafted into the venous stream, with normal femoral artery and vein. Histological changes and alterations in fibrinolytic activity were studied after 15, 30 and 90 days. The two types of arterialized venous graft showed similar aspects: normal endothelium (scanning electron microscopy and F VIII immunofluorescence), marked thickening of the smooth muscle cell layer, disappearance of intimal fibrinolytic activity (Todd's technique, quantified by morphometric analysis), associated with a marked increase of antiplasmin activity (Noordhoek Hegt's technique), increase in the activity of vascular plasminogen activator (measured with chromogenic substrates). The venous grafts in the venous stream showed no changes compared to the normal femoral vein. The proliferation of smooth muscle cells following exposure of a segment of vein to arterial conditions appears to be associated with increased synthesis of both an inhibitor of fibrinolysis (antiplasmin), and of vascular plasminogen activator. The contribution of these two factors to the development of the morphological changes in the vessel requires further study.

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The composition of the bronchial branches of the vagus nerves was studied in cats using light and electron microscopy. In order to determine the number and the diameter of fibers in the afferent and the efferent components, a unilateral efferent vagotomy was performed. The myelinated and the non-myelinated fibers were counted from the total nerve area and the endoneural area of each one was measured by means of a computer. Composition of "afferent" bronchial nerves (after degeneration following the efferent vagotomy) was compared to that of "entire" nerves. The main results are: (1) efferent fibers represent about 40% of the "entire" bronchial nerve; (2) non-myelinated fibers constitute more than 90% of the total population of the "entire" nerves as well as of the efferent component; (3) the density of myelinated and non-myelinated fibers (i.e. their number per surface unit) was similar in all nerves. However, there were discrepancies between diameter histograms established from different areas of a section. This feature seems to be due to preferential compartmentalization by Schwann cell envelopment of fibers having comparable diameter. This "packing effect" was observed in both efferent and afferent components.

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In this experimental work, morphological aspects of different vein grafts were studied using both light microscopy, transmission electron microscopy and scanning electron microscopy. The correlation was made with their fibrinolytic activity ; 21 dogs were operated on under general anaesthesia ; "venous grafts" (perfusion of the vascular segments with venous blood) were performed by excision of the femoral vein with reanastomosis at the same site (protocol P1). "Arterialised grafts" (perfusion of a segment of vein with arterial blood at arterial pressure) were performed according to two protocols : P2 in which a segment of femoral artery was replaced with a segment of reversed femoral vein ; P3 in which a segment of femoral artery was by passed with the femoral vein left in situ after destroying the valves using a Fogarty balloon without damage of the intima. The factors affected by surgery are, therefore, disconnection of the vasa vasorum by excision of the vessel in protocols P1 and P2 and increased oxygenation and luminal pressure in protocols P2 and P3. In all the cases, endothelial cells retained the morphological characteristics of venous endothelium. However, the vein grafts in the arterial circulation were thickened and the fibrinolytic activity was changed. Pathogenic mechanisms of these changes are discussed.

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A total of 109 subjects aged 60 years or more and without any focalized cerebral lesions were studied by E.E.G. and C.T. scan recordings. An original type of planimetric study of the C.T. scan sections was used to obtain numerical ratios of the degree of cerebral atrophy. The planimetric ratios and the E.E.G. data were then studied as a function of age-group and clinical condition. Most of the data obtained was then treated in a computer. Ventricular dilatation is a constant and progressive feature of normal aging, and is therefore correlated with its, whereas it cannot be significantly correlated with senility changes. The E.E.G. shows no precise correlation with age during normal aging but reflects the functional disturbances of senility disorders, especially dementias. There is no correlation between the E.E.G. and C.T. scan results either during normal or pathological aging.

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Sizes for ovarian stroma cells in culture are according to a log normal distribution. Cell stimulation by H.C.G. promotes a significative decrease of these sizes.

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This study is based on the investigation by light and electron microscopy of hepatic biopsies from 14 rats rendered diabetic by streptozotocin and treated by portal embolization of islets of Langerhans. Macroscopically, voluminous projecting cysts were observed, sometimes occupying a whole lobe. By light microscopy, the cysts were lined with canalicular-type epithelium. Ultrastructural studies confirmed the canalicular nature of these cells and cilia were frequently observed. The presence of identical cysts in rats rendered diabetic by streptozotocin but not treated by embolization proves that this product is the agent responsible for the induction of this adenomatosis.

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The ultrastructural localization of 3 beta hydroxysteroid ferricyanide reductase, glucose-6-phosphate ferricyanide reductase and nicotinamide adenine dinucleotide and reduced form-ferricyanide reductase was investigated in some human steroidogenic tissues (corpus luteum of pregnancy, fetal adrenal gland and testis, adult testis and placenta) using ferricyanide as an electron acceptor. Copper ferrocyanide deposits were readily observed in the mitochondria, in the smooth endoplasmic reticulum profiles and in the cytoplasm. The sites of the various dehydrogenase activities could be visualized by using appropriate incubating media. The precise localization of various reactions in different electron transfer chains was determined by using different ferricyanide concentrations and intermediate electron-carriers such as menadione or exogenous nicotinamide adenine dinucleotide and reduced form-diaphorase. The use of respiratory chain inhibitors such as rotenone or antimycine A confirmed these data.

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