Biomedical subjects
Publications and source records attributed to P Franchimont.
HHW-kininogen has been purified from human plasma. We have then studied the optimal conditions for labeling this protein with 125I. This molecule has been used for the preparation of a radioimmunoassay. We have studied the analytical performances of our dosage : sensitivity, precision, accuracy and specificity.
Prostatic acid phosphatase has been isolated from human seminal plasma. The purification method utilizes gel filtration on Sephadex G100, ammonium sulfate precipitation and a series of chromatographical steps including concanavalin A Sepharose 4B, anion exchange and gel filtration chromatography. The final product appears homogenous when analyzed by gel filtration on Sephadex G100. It gives one major band on SDS polyacrylamide gels. The specific activity is similar to that obtained by other purification schemes. The yield of the method described above has allowed to set up a sensitive radioimmunoassay of prostatic acid phosphatase.
The human articular cartilaginous proteoglycans (PG) R.I.A. is highly specific. The PG used as the standard and the 125I labelled molecule appear to be pure. Under these conditions, all the potential interfering substances which have been tested show no cross reaction. For instance, the Ag-Ab equilibrium is not affected by adding human IgG, human albumin, hyaluronic acid, chondroitin sulfate, rat type II collagen or total human serum proteins. This R.I.A. also exhibits a species specificity since there is no cross reaction with rat PG and negligible cross reaction with dog PG. The results obtained after addition of enzymes to the antigen demonstrate that the antigenic sites are localized on the protein region and not on the glycosaminoglycan region of the molecule.
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A case of ovarian androblastoma (arrhenoblastoma) of the intermediate differentiation type in a 5-year old girl is reported. The clinical features were precocious isosexual puberty with secondary masculinization. The tumour was removed but relapsed 26 months later, requiring ovariectomy and salpingectomy. The patient, who has now been followed up for 7 years and 6 months, is definitely cured. Biochemically, the androblastoma was accompanied by high plasma levels of oestrogens, androgens and, quite exceptionally, human chorionic ganodotropin, alpha HCG and beta HCG. Light and electron microscope examination failed to differentiale Sertoli cells from granulosa cells and Leyding cells from luteinized ovarian stroma cells. Areas resembling syncytiotrophoblastic cells were very limited and could not be seen under the electron microscope. Some cells looked like undifferentiated germ cells. The HCG secreted was biologically active on rabbit ovaries (Reiprich's reaction) but inactive on the girl's contralateral ovary, which was found on two biopsies to be unstimulated and prepubertal.
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Homologous radioimmunoassays have been developed for native hCG and its alpha and beta subunits. Their specificities were assessed by analysis of the inhibition ca and beta subunits. 1. During normal singleton and twin pregnancies.
Using specific homologous radioimmunoassays of native hCG and its alpha and beta subunits, we determined the levels of these glycoproteins in unfiltered maternal blood serially obtained in five non-invasive hydatidiform moles before and after evacuation. Some of these samples were assayed after gel filtration chromatography on Sephadex G 100. Twelve samples, obtained in cases of invasive trophoblastic tumour after ablative surgery and chemotherapy, were also assessed for their hCG, hCG alpha and hCG beta content. In unaborted moles, mean circulating levels of native hCG and free hCG beta were considerably increased (seven and thirteen times, respectively) as compared to normal pregnancies of the same age, whereas levels of free hCG alpha were either normal or slightly elevated. Chromatographic analyses of molar sera confirmed the presence of free circulating subunits, and separated hCG beta in its monomeric form from its higher molecular weight form, the latter being in greater quantity than in normal pregnancy sera. In contrast, the elution profile of serum native hCG was comparable in cases of normal and molar pregnancy. Successful curettage was accompanied by a return to normal levels of the native hCG and its alpha and beta subunits in 40-90 days. Persistence of tumour tissue was indicated by a slight increase in levels of native hCG and the beta subunit. Determination of alpha subunit level was less useful for the detection of any relapse.
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The testis and the ovary produce peptidic substances acting at the gonad level to regulate several reproductive functions. They may be called cybernins. Some of them are well identified. Thus, granulosa cells secrete into follicular fluid an oocyte maturation inhibitor (OMI) which inhibits the meiosis resumption until preovulatory LH peak. Follicular fluid also contains A FSH receptor binding inhibitor (FSH RBI) which seems to be implied in maintaining the follicles at immature stages or in leading them to atresia. FSH RBI is also found in testis extract. Luteinization inhibitor (LI) probably acts to keep granulosa cells from luteinization prematurely and inhibits progesterone secretion. Inhibin is produced by Sertoli cells in male and by granulosa cells in female. It inhibits FSH synthesis and secretion by the pituitary cells via a classical feedback mechanism. Furthermore, it directly decreases spermatogonial mitosis and progesterone secretion by granulosa cells as demonstrated by "in vitro" experiments. LH receptor binding inhibitor (LH RBI)is found in corpus luteum. As the corpus luzeum ages, it contains more of LH RBI. This cybernin which reduces progesterone secretion by granulosa and luteal cells is a possible factor involved in luteolysis. Gonadocrinins, produced by the ovary and the testis, release gonadotrophins from pituitary cells like hypothalamic LH-RH. They also bind to specific receptors on Leydig and Thequa Interna cells inducing a reduction of prolactin and LH receptor number. Steroidogenesis and gametogenesis are thus impaired. Biochemical structures of these cybernins are still unknown as their physiological and biochemical interrelationships.
Three preparations of inhibin extracted from ram rete testis fluid (RTF) and from human seminal plasma (HSP) reduce tritiated thymidine incorporation into testicular desoxyribonucleic acids (DNA) in vitro. Effect of low molecular inhibin from RTF is dose-dependent. Castrated ram serum does not modify testicular DNA synthesis in vitro. Besides their suppressive action on follicle stimulating hormone (FSH) secretion in vivo and in vitro, these inhibin preparation display a direct inhibiting effect on testicular DNA synthesis and, thus, on mitotic activity. Identity between inhibin and testicular chalones are discussed.
In vivo, Enkephalins, stimulate PRL, inhibit LH and are inactive on FSH. However, in monolayer pituitary cell cultures, PRL, LH and FSH secretions and synthesis are not modified by Met-Enk. (5 microgram/ml) or Leu-Enk. (5 and 10 microgram/ml). But the simultaneous presence of LHRH and Enk. induces an increase in LH secretion and synthesis without modifying FSH and PRL. In conclusion 1) Enk do not act by themself at the pituitary level but 2) they are able to modify the responses induced by hypothalamic hormones.
The maternal serum levels of hCG and its alpha or beta subunits were measured in 96 normal pregnancies and correlated with the fetal sex. During the first 20 weeks (69 cases), the maternal serum levels of hCG, of its alpha subunit and particularly of its beta subunit were higher in cases of female fetuses. However no statistically significant difference was observed between the levels of hCG or its subunits in serum of pregnancies with male or female fetuses. During the second half of pregnancy, the serum hCG levels were discretely higher in cases with female fetuses (no significant difference) and the serum levels of its alpha or beta subunits were identical in cases of male of female fetuses.
A radioimmunoassay for low molecular weight (LMW) human Kininogen has been carried out. The first step was to prepare LMW Kininogen from human plasma. The proposed method allowed to get chemically pure and biologically active LMW Kininogen. This preparation was used to induce antibody. Optimal conditions for labelling and incubation were determined. This method may be applied to the assay of Kininogen in human plasma.
Proteoglycans (PG) have been purified by classical methods from human articular cartilage in order to set up a radioimmunoassay. Conditions of labelling, purification of labelled PG, and optimal conditions of buffer, temperature, duration of incubations and dilution of antiserum are described. Separation of free and bound PG is performed by immunoprecipitation. It is demonstrated that human articular PG can be assayed quantitatively by RIA procedure, with the sensitivity of +/- 2 femto-moles (+/- 5 ng) per tube.
17 beta oestradiol and inhibin production by Sertoli cells has been investigated in vitro. In basal conditions, 17 beta-oestradiol secretion is weak whereas inhibin production is undetectable on days 7 and 9 of culture. Addition of PMSG (FSH-like gonadotrophin) and testosterone to the culture medium induces a simultaneous increase in 17 beta-oestradiol and inhibin production. PMSG alone has no effect neither on inhibin nor on 17 beta-oestradiol secretion. Testosterone alone significantly increases 17 beta-oestradiol and inhibin production. Human chorionic gonadotrophin (LH-like gonadotrophin) does not modify inhibin secretion. Dihydrotestosterone stimulates inhibin production without affecting oestrogens secretion. Thus, stimulation of aromatization of testosterone into 17 beta-oestradiol is associated with an increase of inhibin production, but this effect seems to be due to a direct action of androgens.