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Biomedical subjects

G Morel

Publications and source records attributed to G Morel.

At least 145 records · Page 8Linked to original sources
PubMed1984

Ultrastructural evidence of progesterone receptor by immunochemistry.

Antiserum against purified chick oviduct non-transformed "8S"-progesterone receptor has been used for detecting progesterone receptor in rat pituitary cells at the ultrastructural level after immunochemical reaction according to Sternberger. In prepubertal (21-day-old) and adult (diestrus) female rats, the gonadotropic, lactotropic and somatotropic cells were positive, but not the corticotropic and thyreotropic cells. In all positive cases, the progesterone receptor-like antigen was found in both the cytoplasm and the nucleus. Two hours after progesterone administration to immature rats, there was an increase of receptor-like antigen in nuclei of gonadotropic cells. These results and the immunological controls related to antibody specificity give the first evidence of progesterone receptor at the ultrastructural level. They remarkably show that its distribution in pituitary cells parallels the distribution of the estradiol receptor.

Animals↗
PubMed1984

Ultrastructural evidence for endogenous growth hormone-releasing factor-like immunoreactivity in the monkey pituitary gland.

Growth hormone-releasing factor-like immunoreactivity was visualized in monkey pituitary gland by immunocytochemistry on ultrathin sections obtained by cryoultramicrotomy. Antibodies were raised against synthetic human pancreas growth hormone-releasing factor (1-40). Growth hormone-releasing factor-like immunoreactivity was observed in somatotropes (identified by immunocytochemistry) only. The other pituitary cell types were not immunoreactive. In somatotropes, immunoreactivity was observed at the plasma membrane but only very scarcely, in the cytoplasm (cytoplasmic matrix and secretory granules) and in the nucleus. These results (1) provide immunocytological evidence for the presence of growth hormone-releasing factor or of an immunoreactive fragment of its molecule in the pituitary; (2) indicate the presence of this peptide in one particular pituitary cell type; and (3) provide cytological evidence for direct participation of growth hormone-releasing factor in the regulation of the somatotropic function.

Animals↗
PubMed1984

Influence of gonadoliberin on the differentiation of rat gonadotrophs: an in vivo and in vitro study.

The influence of gonadoliberin (GnRH) on the differentiation of rat gonadotrophs in early fetal life was studied both in vivo and in vitro by immunocytology with anti-porcine luteinizing hormone beta (pLH beta) serum. Adenohypophysial primordia explanted from 11 to 13 days of gestation were maintained in organ culture in synthetic Parker's 199 medium enriched with insulin (0.5 microgram/ml) and transferrin (5 micrograms/ml). Cultures lasted to approximate the usual gestation period (21 days). Synthetic GnRH (10(-9) or 10(-12) M) was added to the culture medium during the first day of culture only. In contrast to a previous report, immunoreactive cells were detected in the primordia explanted either at 11 or 12 days of gestation only when cultured in the presence of GnRH. The appearance of positive localization was seen by 17 days. No differences due to GnRH dosage were observed in the mean cytoplasmic area of the cells in the different experimental groups as seen at the equivalent of 21 days. GnRH was not effective in a medium deprived of insulin. GnRH, added 6 h before the end of the culture, could also release the secretory product of gonadotrophs which recently developed the presence of immunoreactive pLH beta material. In these conditions, GnRH was shown to enter the cells as observed by immunocytochemistry on sections obtained after cryoultramicrotomy. Endogenous GnRH was also detected by the same technique in fetal pituitary glands removed from 14 to 21 days of gestation. It was always localized in agranular cells and from 18 days in some granular cells considered as gonadotrophs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[An unknown after surgical lengthening of the femur in children: spontaneous postoperative parasitic lengthening].

The authors have studied overgrowth or diminished growth seen in 54 femora lengthened surgically by a one-stage procedure between 1963 and 1979. Thirty six cases were of poliomyelitis. An overgrowth was regularly seen of the order of 2.5 p. 100- that is 11 mm on average. This stimulation of growth by lengthening was not related to age. It was more marked where there was severe involvement. In contrast, in 13 cases of congenital femoral abnormalities and 5 cases of miscellaneous diseases (Ollier's disease, neurofibromatosis, sequelae of septic arthritis) overgrowth or diminished growth have been observed. This phenomenon was not constant and could not be predicted.

Age Factors↗
PubMed1983

[Epidemiology of multiple sclerosis in Brittany].

In the period 1976-1978 a study of the prevalence of multiple sclerosis in Brittany was conducted using data collected from hospital neurology units, Social Security offices and institutions for chronic patients. After elimination of double entries, analysis of these data showed a prevalence of 25 for 100 000 people. This was less than expected from estimates for northern France and from the known prevalences in the southern part of the British isles. When broken down according to the patients' place of residence, the figures were found to vary from one district to another, with four main foci: two near the coast, one inland and one in the town of Fougères. Disease-free areas were present near these foci.

Climate↗
PubMed1983

Cryoultramicrotomy versus plastic embedding: comparative immunocytochemistry of rat anterior pituitary cells.

The anterior pituitary of the rat is used as a model for the study of the effects of freezing or plastic embedding on the maintenance of antigenicity. Rat anterior pituitaries are fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer pH 7.4. Some of the blocks are post-fixed before being divided into two lots. One batch is frozen, while the other is dehydrated and embedded. The indirect antibody enzyme method is applied to ultrathin sections obtained by cryoultramicrotomy after freezing or by sectioning after embedding. All six pituitary hormones are detected by both methods. Comparison shows that the morphological characteristics are identical for both techniques, though ultrastructural preservation is better after embedding. Immunoreactivity is found in secretory granules and sometimes in the endoplasmic reticulum. Osmium postfixation may reduce or even abolish antigenicity in plastic-embedded tissue. After cryoultramicrotomy, however, even after osmium fixation, antibody may be used 1000 times more diluted than after plastic embedding. Embedding preserves ultrastructure and limited antigenicity while the use of cryoultramicrotomy is a far more sensitive technique.

Adrenocorticotropic Hormone↗
PubMed1983

Ultrastructural aspects after cryoultramicrotomy of bone tissue and sutural cartilage in neonatal mice calvaria.

Using transmission electron microscopy after cryoultramicrotomy, mineralized as well as unmineralized bone tissues and sutural cartilage were observed in neonatal mice calvaria. A good definition of osteoblasts (nucleus, membranes, organelles) and extracellular constituents (collagen fibrils, matrix vesicles, mineral substance) was obtained. The sutural zone was composed of an unmineralized cartilaginous tissue with more or less hypertrophic cells surrounded by a finely fibrillar matrix.

Animals↗
PubMed1983

Ultrastructural evidence for endogenous somatostatin-like immunoreactivity in the pituitary gland.

The tetradecapeptide, somatostatin (SRIF), is a potent inhibitor on pituitary hormone release, by a direct effect. The immunocytological method was used with the aim of localizing SRIF at the cellular and subcellular levels. Rat pituitaries were fixed and frozen. Ultrathin sections obtained by cryoultramicrotomy, were incubated with anti-SRIF serum. The antigen-antibody reaction was detected by 4-chloro-1-naphthol. SRIF immunoreactivity was observed in somatotrophs, thyreotrophs and prolactin cells, but not in corticotrophs or gonadotrophs. Im immunoreactive cells, SRIF was found in the cytoplasmic matrix, in the secretory granules and in the nucleus distributed primarily in the euchromatin, in the vicinity of the heterochromatin regions. SRIF immunoreactivity was also observed at the plasma membrane. No immunoreactivity was observed when nonimmune serum or anti-SRIF serum incubated with SRIF was used. No modification was observed when anti-SRIF serum incubated with gonadoliberin, thyroliberin or vasopressin was used. These data (1) provide immunocytological evidence for the presence of somatostatin in pituitary gland, and (2) indicate the presence of SRIF peptide in the somatotrophs, thyreotrophs and prolactin cells.

Animals↗
PubMed1983

[Extemporaneous femoral lengthening by the Cauchoix technic in children and adolescents].

One hundred and thirty-eight femoral lengthening operations have been performed in 133 children. The etiology of the shortening was poliomyelitis in 71, infection in 20 and congenital abnormalities in 28. The femur was lengthened in one operative stage by step-cut osteotomy, immediate traction and plate fixation. The mean gain was 35 mm with a maximum of 55 mm. The range of knee movement was unaffected except in 6 cases. Infection occurred in 2 patients without prejudicing the final result. Bony union was obtained in all cases, bone grafting being necessary only once. One permanent sciatic palsy was seen. Thirteen fractures occurred in 9 femurs. Two occurred during operation with loss of lengthening in one case. Eleven occurred post-operatively at the site of osteotomy. One case fractured on 3 occasions. Two cases fractured in another portion of the femur. The complications became fewer with experience and with more accurate technique and it is concluded that the method is safer than progressive lengthening at least in moderate limb length discrepancy.

Adolescent↗
PubMed1982

Ultrastructural evidence for endogenous vasoactive intestinal peptide-like immunoreactivity in the pituitary gland.

The immunocytological method was used to investigate whether vasoactive intestinal peptide (VIP) is present in the pituitary gland and to localize the peptide at the cellular and subcellular levels. Pituitaries of Wistar male and female rats (Iffa Credo) were fixed in glutaraldehyde 2.5% and postosmicated and frozen in liquid nitrogen. Ultrathin slices, obtained by cryo-ultramicrotomy were incubated with the antiserum. The antigen-antibody reaction was detected by peroxidase-antiperoxidase complexes revealed by 4-chloro-1-naphtol. The prolactin (PRL)-secreting cells were identified by using an anti-oPRL antiserum. The PRL immunoreactivity was localized in secretory granules of irregular shapes. An anti-VIP serum was used which neither cross-reacted with the several fragments of VIP molecule nor with peptides from gut or hypothalamus. The VIP immunoreactivity obtained with this antiserum, was observed in PRL cells only but never in so-matotropic, gonadotropic, corticotropic and thyrotropic cells. The immunoreactivity was localized in the cytoplasmic matrix between and around the secretory granules but not in the organelles, and in the nucleus distributed all over the euchromatin near to the heterochromatin regions. No reaction was observed by using either nonimmune serum or anti-VIP antiserum incubated with VIP. No modification of VIP immunoreactivity was observed by using anti-VIP antiserum incubated with somatostatin, gonado- or thyroliberin. These data (1) provide immunocytological evidence for presence of VIP in pituitary gland; (2) indicate the presence of this peptide in one particular pituitary cell type, and (3) support the hypothesis that VIP could have a direct effect on the control of PRL secretion.

Animals↗
PubMed1982

Immunocytochemical evidence for gonadoliberin in rat anterior pituitary gland.

Endogenous gonadoliberin was localized by using immunocytological methods in the hypothalamic neurons which synthetize the peptide and in the hypophysial target cells. The rat tissues were fixed and frozen. Ultrathin sections were obtained by cryoultramicrotomy. In the pituitary gland, GnRH was observed in both gonadotropic and prolactin cells. In these cells, endogenous GnRH was observed in the secretory granules, in the cytoplasm and in the nucleus. After castration an increase of immunoreactive GnRH was observed; after injection of a potent agonist (D-Trp6-Pro9-Net-LRF) or an antagonist (D-pGlu1, D-Phe2, Trp3,6 LRF) endogenous GnRH staining was decreased. These data suggest that endogenous GnRH could be bound to a site having a high affinity for GnRH.

Animals↗
PubMed1982

Ultrastructural evidence for endogenous substance-P-like immunoreactivity in the rat pituitary gland.

Substance P (SP) is known to act on pituitary hormone release either at the hypothalamic level or directly at the pituitary level. In order to investigate whether SP is present in the pituitary gland and to localize the peptide at the cellular and subcellular levels, the immunocytological method was used. Rat pituitaries were fixed and frozen. Ultrathin sections, obtained by cryoultramicrotomy, were incubated with anti-SP serum. The antigen-antibody reaction was detected by 4-chloro-1-naphtol. SP immunoreactivity was observed both in the prolactin and in the gonadotropic cells, but not in the somatotropic, corticotropic and thyrotropic cells. In reactive cells, SP immunoreactivity was observed in the secretory granules, in the cytoplasm, and in the nucleus distributed all over the euchromatin near to the heterochromatin regions. No immunoreactivity was observed when nonimmune serum or anti-SP serum incubated with SP was used. No modification of the immunocytochemical reaction was observed when anti-SP serum incubated with somatostatin, gonado- or thyroliberin was used. These data (1) provide immunocytological evidence for the presence of SP in the pituitary gland; (2) indicate the presence of SP peptide in the gonadotropic and prolactin cells only. They support previous findings indicating that SP could have a direct effect at the pituitary level.

Animals↗
PubMed1982

Pneumatic trouser splints in the treatment of severe osteogenesis imperfecta.

Twelve patients with severe osteogenesis imperfecta have been managed by closed osteotomy to correct lower limb long bone deformity, followed by support in pneumatic trouser splints. The apparatus was well tolerated, fractures were rare, and there was a significant improvement in patient mobility. This conservative method compares favourably with the published series of multiple osteotomies and intramedullary rodding.

Bone Diseases, Developmental↗
PubMed1981

[Ultrastructural localization of estradiol and moxestrol in the gonadotropic cells of rat by immunocytology after cryo-ultramicrotomy: evidence for hormonal specificity (author's transl)].

Estradiol (E2) was specifically localized by immunocytochemistry in the cytoplasm and in the nucleus of the gonadotropic cells. The immunocytochemical reaction was not observed after injection of moxestrol, but it was not modified by injection of testosterone, progesterone, or dexamethasone. These data suggest that E2 might be bound to a high-affinity binding-site which could also have a hormonal specificity.

Animals↗
PubMed1980

[Variations of testosterone uptake by gonadotropic cells of the adenohypophysis of the rat].

Testosterone (T) could be detected by immunocytochemistry after cryoultramicrotomy and T is likely bound on a binding site of a high affinity. Castration and adrenalectomy involve a swift disappearance of T in the gonadotropic cells. Synthesis of new binding sites was induced by daily T injection in the castrated and surrenalectomized Rat from 90 days. This synthesis is inhibited by cycloheximide. These data suggest that binding sites are proteins. The captation of T by the gonadotropic cells was diminished similarly at the diminution of T, afterwards, T captation was stabilized at a weak level which became stable for several weeks. It seems that immunocytochemistry permits the study of the variation of T captation by Rat pituitary gonadotropic cells.

Adrenalectomy↗