Biomedical subjects
A Clavert
Publications and source records attributed to A Clavert.
[Effects of an extract of the bark of Pygeum africanum (V.1326) on prostatic secretions in the rat and in man].
Treatment with V.1326 in the rat induces an increase in prostatic secretion. In men with insufficient prostatic secretion, this treatment also induces an increased secretion.
Soluble seminal fluid proteins from various animal species.
When soluble seminal proteins from different animal species are studied by cellulose acetate electrophoresis, important differences can be observed. These differences may be related to the type of coitus and the storage and migration of spermatozoa in the female genital tract. Seminal fluid can play a role in spermatozoal maturation by affecting the distribution of the surface charge of spermatozoal membranes.
Sperm cryopreservation preceding treatment of testis cancer.
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Effects of prostatic secretion on reduced sugars in human seminal plasma.
Glucose and fructose levels were determined enzymatically in liquefied human seminal plasma (whole or collected in three fractions) and in preparations obtained by DEAE ion-exchange chromatography on whole seminal plasma. When these secretions or DEAE-extracted preparations were overloaded with fructose, the level of glucose increased. This increase is greater in fraction I of split ejaculates than in fractions II and III, and is greater in solutions containing elements of prostatic secretion obtained chromatographically than in whole seminal plasma. Using increasing quantities of fructose in the overloading test, glucose levels reached a maximum, suggesting that the process of conversion of fructose into glucose appears to be related to an enzymatic process. Other experiments suggest that the sperm-free fraction I of split ejaculates and compounds obtained from seminal plasma by ion-exchange chromatography contain enzymes of prostatic origin that are involved in the conversion of fructose to glucose.
Reactivation of the secretion from the prostatic gland in cases of reduced fertility. Biological study of seminal fluid modifications.
The efficiency of Pygenum africanum treatment was tested on a population where the acid phosphatase activity was shown to be reduced at two successive examinations. The treatment caused an increase in acid phosphatase activity and total protein secretion. However, the fact that the men who had IgA present in their ejaculate reacted more favorably to the treatment shows that Pygenum africanum is more efficient in cases where there is no prostate gland inflammation.
Acute experimental E. coli epididymitis in the rat and its consequences on spermatogenesis.
The injection of E. Coli into the tail of the epididymis in the rat caused epididymitis. In 20% of the cases, the inflammation is spread through the lymphatic system to the testis. The germinal cells are destroyed in 50% of the cases by the second day, and are not reestablished for several months. Signs of testicular inflammation are not found. The destruction seems to be caused by E. Coli toxins, as shown by injections of killed bacteria.
[Relation between spermatozoids and reducing sugars (glucose and fructose) in human seminal fluid].
The prostatic fraction of seminal plasma contains components that are involved in the process of transforming fructose into glucose. If a positive correlation can be found between the slope of the decrease of fructose (estimated to be between 30 minutes and 5 hours) and the sperm count, with at the same time the maintenance of a relatively constant glucose level, then we have been able to demonstrate that glucose is more efficient than fructose to keep spermatozoa mobile. The enzyme process involved in transforming fructose into glucose may thus act to maintain definite glyspermia with a maximum value of 1.8 g/l. Aspermia in some circumstances then can be related to the absence or poor function of the transformation process and thus with the absence or decrease in prostatic secretion.
Pathological seminal plasma proteins by cellulose acetate electrophoresis.
Pathological seminal liquids were studied by using cellulose acetate electrophoresis as well as biochemical doses of proteins, acid phosphatases, reducing sugars, and zinc. It was also possible to show the frequent total absences of vesicular secretion, less frequent than prostatic secretion and less than the two at the same time. It was also shown that reductions were more frequent in prostatic secretion than in vesicular secretion. This method may also be a valuable assistance in the diagnosis of certain urogenital infections. The dissociation between prostatic secretions of acid phosphatases and zinc may lead to the diagnosis of the infection in the posterior or lateral lobes of the prostate.
[The interpretation of athenospermia as a function of the parameters in a spermogram (author's transl)].
The study of spermiograms, conducted on patients consulting for sterility, showed relationships between motility and other variable factors of the sperm. Testicular and prostatic factors are involved in immediate asthenospermia, whereas factors are involved in secondary asthenospermia.
[Epididymal hypertrophy after subepididymal hemicastration].
Following hemicastration, the epididymis on the non-operated side progressively hypertrophies and remains in this state for an unlimited length of time. This modification is due to an increase in androgens from the remaining testicle via lymphatics and/or lumen. This increase in weight seems to be due to an increase of testicular content by activation of in situ cells.
Experimental approach to the pathogenesis of the anomalies of amniotic disease.
By intra-adnexal injection of glucose in the rabbit embryo, we were able to stimulate all the anomalies associated with "Amniotic Disease". Since we were even able to obtain amniotic bands, this study provides an excellent experimental model of this disease. Resulting lesions occur early in development, corresponding to the first trimester of human gestation. All of the anomalies can ultimately be explained by the destruction of the most superficial cells: epiblastic cells of the embryo and the amnion, subjacent mesenchyme, and endothelial cells. The subsequent lack of interaction between these cells and the importance of the anatomical localizations of resulting hematomas can lead to the pathogenetic approach to this disease. In light of the present study, the disease appears to be caused by an external factor within the amniotic fluid. The exact nature of the destructive agent(s) remains a mystery in man.
In vitro studies on differentiation of the optic stalk in the chick embryo.
An orderly pattern of cell death accompanies growth of retinal ganglion cell axons through the optic stalk of the chick embryo. In order to determine if the cell death process in this anlage is preprogrammed at earlier stages or if other factors play a role, we cultured optic stalk primordia at a stage prior to retinal differentiation, either alone or in the presence of head or limb bud mesenchyme. When optic stalk was cultured alone, many cells differentiated into neurons. However, when mesenchyme cells of either head or limb bud origin were combined with the stalk, the stalk cells either degenerated, were unrecognizable in the mesenchyme mass, or retained their epithelial arrangement and became pigmented. Mesenchyme and/or neural crest which normally migrate around the stalk at the same time that ganglion cell axons penetrate this structure may therefore be involved in some aspect of the cell death process. Since many optic stalk cells in vitro differentiate into neurons, these cells may represent the population of cells which in situ would normally die.
[Study of the vascularization of the epididymis].
The pampiniform system plays an important role in the thermoregulation and the concentration of hormones in the testicle. The study of the vascularization of the testicle and of the epididymis shows an independent vascularity in the case of the rabbit. The arteries of the head of the epididymis leave the spermatic artery before the establishment of the particular relationships which exist between the testicular artery and the pampiniform system. Temperature monitoring shows no difference between these two organs. It appears in this case that the thermo regulation is achieved essentially by the scrotum. It is not possible to say if any hormonal exchange takes place between the testicle and the epididymis.
Cell death and optic fiber penetration in the optic stalk of the chick.
The role of dying cells in the optic stalk in relation to retinal fiber migration was investigated in the chick embryo. Cell death was analysed at various stages of development by counting pycnotic nuclei and also by the Gomori acid phosphatase reaction, while nerve fibers were visualised by the Bodian method. A wave of cell death, beginning in the neural retina at stage 18 and advancing with time through the stalk towards the diencephalon, occurred simultaneously or slightly prior to differentiation and migration of ganglion cell axons. Cell death stopped and gliogenesis occurred in the stalk after penetration by retinal fibers. Cell death occurred in the stalk even when fiber penetration was prevented by optic cup ablation. In this case, necrosis ensued until almost complete degeneration of the stalk, usually within three days after the operation, and gliogenesis did not occur. As the stalk degenerated, its cells became heavily pigmented. These observations suggest that the onset of cell death in the optic stalk is determined prior to and independently of retinal fiber penetration. On the other hand, cessation of cell death and subsequent gliogenesis occur only in the presence of ingrowing optic fibers.
Abnormal children of a 47,XYY father.
Abnormal children of two 47,XYY men were studied. One of these men had 2 normal daughters and a child, 45,X/46,XY, with gonadal dysgenesis. The other man had 2 normal sons and a child with Down's syndrome. The extra chromosome 21 of this child came from the mother. Another 47,XYY man had 4 normal children.
[Alterations in concanavalin A binding during retinal development in Xenopus laevis].
Changes in concanavalin A binding were observed in the retina of Xenopus laevis throughout development. Prior to stage 37, the optic cup and nervous sysetm displayed a light, diffuse staining. Abruptly at stage 37, however, intense staining reaction occurred in the ganglionic fibers, both plexiform layers and photoreceptor inner segments, remaining thus throughout larval and adult life. Our results suggest that important structural modifications occur in retinal cells at the time of establishment of connections with the tectum, preceedings, and possibility related to, electrical functioning of the visual system.
The use of avian double monsters in studies on induction of the nervous system.
Ninety-eight duck double monsters (siamese twins) were studied between 48 and 72 h of incubation in whole-mount or serial-sectioned preparations. Each case was classified into one of four categories depending on the orientations of the two embryonic axes. In all classes, defects in primary neural induction of various parts of the embryonic nervous system were observed which depended to a large extent on the distance separating the anterior tips of the two notochords or on the relative positions of the notochords. Our observations suggest that: when the same inducing field of one embryo overlaps to a critical extent with that of the twin, the two inducers act as one; induction of forebrain and optic vesicles is purely prechordal; the notochord exerts an inhibition on induction of forebrain by prechordal mesoderm; and the presence of rhombencephalic structures depends on both prechordal and chordamesodermal interactions.