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Biomedical subjects

M Roger

Publications and source records attributed to M Roger.

At least 127 records · Page 7Linked to original sources
PubMed1990

Distribution of the efferent projections of the rat posterior thalamic nucleus as revealed by Phaseolus vulgaris immunohistochemistry.

Following iontophoretic injection of Phaseolus vulgaris in the rat posterior thalamic nucleus (PT) dense terminal fields were labeled in the ipsilateral red nucleus, zona incerta, intermediate and deep layers of the superior colliculus, pretectum, basilar pontine gray, and dorsal pole of the caudal division of the ventral lateral thalamic nucleus. Several other structures were more sparsely labeled; the reticular gigantocellular and pontine oral nuclei, nucleus of the mesencephalic tract of the trigeminal nerve, deep mesencephalic and posterior hypothalamic nuclei and the rostral part of the lateral posterior thalamic nucleus. The motor and, to a lesser extent, somatosensory cortices were labeled only following tracer injection in the rostral PT. The posterior thalamic nucleus thus projects to several centers primarily treating somatosensory and/or nociceptive messages, and to precerebellar and motor nuclei. Since a previous study has established that the PT also receives a major somatosensory and/or nociceptive input (Roger and Cadusseau, 1984), a non-specific, modulatory role of the PT is therefore proposed in the treatment of some aspects of somatosensory and/or nociceptive information.

Animals↗
PubMed1990

[Result of 3 years of screening for preclinical phase of juvenile insulin-dependent diabetes mellitus].

We screened 1,000 individuals for pre-type I diabetes mellitus: 927 were first degree relatives of patients treated at our institution, 31 other had related autoimmune diseases, 42 had fortuitously discovered slight hyperglycemia. Islet cell antibodies were present in 31 subjects, 13 adults and 18 children. Among these 18 children, 7 also had complement-fixing islet cell antibodies, and 5 anti-insulin antibodies. All but one initially had a normal insulin response to intravenous glucose. The child with the abolished response, as well as another whose insulin secretion fell down during the study period, became diabetic. Based on these preliminary data, we are developing large scale family screening of pre-type I diabetes.

Adolescent↗
PubMed1990

Changes in gonadotropin and alpha-subunit secretion after a single administration of gonadotropin-releasing hormone antagonist in adult males.

The suppressive effect of the gonadotropin-releasing hormone (GnRH) antagonist Nal-Glu ([Ac-D2Nal1, D4ClPhe2, D3Pal3, Arg5, D-4-p-methoxybenzoyl-2-aminobutyric acid6, DAla10]-GnRH), injected intramuscularly with 5 mg, was studied in six men. Testosterone decreased by 87 +/- 2.3%, whereas the mean drops were 50 +/- 10%, 43 +/- 6.6%, and 39 +/- 5.6% for radioimmunoassayable luteinizing hormone (LH), follicle-stimulating hormone, and free alpha-subunit, respectively (mean +/- SEM). Immunological characteristics of plasma LH were modified during the inhibition and recovery phases as evidenced by comparison between polyclonal and monoclonal assays. In two additional subjects sampled every 10 minutes, both LH and alpha-subunit pulses were suppressed by NalGlu injection and restored by pulsatile GnRH infusion. However, a nonpulsatile and possibly non-GnRH-dependent alpha-subunit secretion was maintained after NalGlu administration.

Adult↗
PubMed1990

[Age-related changes in plasma androstanediol glucuronide in men].

Plasma 5 alpha-androstane-3 alpha, 17 beta diol (Adiol) glucuronide levels were determined using a reliable radioimmunoassay involving hydrolysis with E. coli beta-glucuronidase, diethylether extraction, and Celite column chromatography. Conditions ensuring optimal hydrolysis were determined as well as quality control criteria. Sixty-eight male out-patients wre studied. These subjects were divided into three age groups: I (n = 21; age 20-35 years), II (n = 21; age: 36-50 years), and III (n = 26; age: 51-70 years). Patients under 50 years of age had infertility with no abnormalities upon sperm analysis. Older patients had erectile dysfunction. All subjects had serum gonadotropin (FSH and LH) and prolactin levels within the normal range for age. Adiol glucuronide levels (mean +/- SD) were as follows: 5.0 +/- 2.2 ng/ml (range: 1.6-9.5), 5.4 +/- 3.8 ng/ml (range 1.4-16.0) and 4.5 +/- 2.5 ng/ml (range 1.2-9.3) in groups I, II and III respectively. A trend towards lower Adiol glucuronide levels with advancing age was found but there was no significant difference between group III and the other two groups. Similarly, no significant correlation was found between Adiol glucuronide levels and age (r = -0.12). Conversely, a significant correlation (r = 0.37; p less than 0.01) was observed between Adiol glucuronide levels and bioavailable testosterone (T) levels. This finding might be the consequence of a certain enhancement of 5 alpha-reductase activity with age and/or the non significant decrease with age of another precursor.

Adult↗
PubMed1989

Anatomical study of the connections of the primary auditory area in the rat.

The aim of the present study was to identify in the rat the overall input-output pattern of connections of the primary auditory field, with special attention to the topographical organization of the geniculocortical auditory projection. By using cytoarchitectural criteria, three temporal cortical fields were distinguished in the rat: Te1, Te2, and Te3. The primary auditory field Te1 is characterized by a relatively specific differentiation of its layers when compared with other temporal fields. The afferent and efferent connections of Te1 were identified by using the retrograde and anterograde transport of wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP). The results indicate that Te1 is connected by a dense and reciprocal system of fibers with the auditory thalamus. Based on the nomenclature of Morest ('64) in the cat, five cytoarchitectural subdivisions of the medial geniculate complex (MG) were identified in the rat: ventral (MGv), dorsal (MGd), medial (MGm), suprageniculate (Sg), and peripeduncular (PPA). The major rostrocaudal extent of the MGv is connected to Te1. The surrounding cortical fields Te2 and Te3 do not receive a projection from the MGv, except from its most caudal pole. The MGv projection is topographically organized. When the deposit area of the tracer is shifted from dorsal to ventral upon Te1, the corresponding labeled zone within the MGv moves from rostral to caudal, whereas a cortical displacement of the deposit area of the tracer from rostrodorsal to caudoventral leads to a medial to lateral shift of the labeled zone in the MGv. In addition, more dorsal parts of the MGv project on more dorsal sectors of Te1. Te1 receives a sparser, topographically organized projection from the deep dorsal subdivision of the MGd. The MGm and the lateral part of the posterior group of thalamic nuclei (Pol) also distribute fibers to the primary auditory field. Te1 is reciprocally connected by a system of callosal fibers with the contralateral homotypic cortex. Finally, Te1 sends fibers to the dorsal and, to a lesser extent, external cortices of the inferior colliculus, caudomedial caudate-putamen complex, and caudoventral thalamic reticular nucleus.

Afferent Pathways↗
PubMed1989

Lack of effect in vivo of clofibrate on adrenal steroid secretion.

Clofibrate inhibits the synthesis of adrenal steroids when administered in vitro. In the present study the effect in vivo of clofibrate on adrenal steroid secretion has been investigated. Basal levels of plasma progesterone, corticosterone, aldosterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, dehydroepiandrosterone sulphate and dehydroepiandrosterone, and their response to ACTH 1 mg im, were not reduced by chronic administration of clofibrate 2 g per day p.o. for 8 to 34 days to 6 hyperlipidaemic men.

17-alpha-Hydroxyprogesterone↗
PubMed1989

[Free alpha-subunit glycoprotein hormones: physiological and pathological data].

The glycoprotein hormone alpha-subunit is secreted as a free molecule as well as a molecule combined to a glycoprotein hormone beta-subunit. In human subjects, plasma levels of the free alpha-subunit were measured by means of a specific radioimmunoassay. Plasma concentrations were high during the neonatal period, then decreased to a nadir at the age of 6 years. A significant pubertal increase occurred in both sexes, more pronounced in girls. In female subjects mean levels (+/- SEM) were 0.21 +/- 0.05 before puberty and 0.51 +/- 0.03 ng 1 degrees IRP-hCG alpha/ml in follicular phase. During menstrual cycle, a typical preovulatory surge was seen simultaneous with the LH surge. During aging, plasma levels increased slowly in males, abruptly in menopausal females. The pituitary reserve as assessed by LH-RH stimulation test (100 micrograms i.v./m2) exhibited a significant pubertal maturation in boys and girls. Chronic administration of LH-RH agonist induced a marked increase of alpha-subunit levels, whereas LH levels were deeply suppressed. LH-RH injections in children treated for precocious puberty with a LH-RH agonist induced a significant release of alpha-subunit despite an almost complete abolition of LH release. In conclusion, from a quantitative point of view, the glyco-protein hormone alpha-subunit is a major secretory product of the pituitary. It seems that there is a specific regulation of its secretion, resembling but not identical to LH secretion regulation. Whether or not it plays a biological role remains uncertain.

Child↗
PubMed1989

[Treatment of precocious puberty with an LH-RH agonist (D-TRP6-LH-RH)].

Chronic administration of luteinizing hormone-releasing hormone (LH-RH) is currently considered as the most appropriate therapy of precocious puberty. A delayed release preparation of D-Trp-6-LH-RH (Décapeptyl in microcapsules) designed to release the agonist for 28 days after intramuscular injection of 60 micrograms/kg body wt was given to 12 boys and 26 girls with precocious puberty. Plasma levels of gonadotropins and sex steroids were suppressed to prepubertal levels within 3 weeks, whilst pituitary responses to LH-RH test were almost abolished within 7 weeks. A significant improvement of secondary sex characteristics, as well as gonadal size, was observed within 6 months. Growth velocity (cm/yr, mean +/- SD) was reduced in boys and girls from 9.9 +/- 3.4 and 9.6 +/- 3.3 respectively before treatment to 5.2 +/- 1.0 and 5.3 +/- 1.3 respectively during the third year of treatment. The mean ratio height age/bone age was just before treatment 0.91 in boys and 0.88 in girls and increased to 1 after 3 yr of treatment. This study shows that Décapeptyl in microcapsules induced a prolonged suppression of gonadal function and a relative blockade of bone maturation. A significant improvement of adult height relative to the effect of conventional treatments should be expected.

Female↗
PubMed1989

[Determination of EGF receptors (epidermal growth factor) in the placenta and breast tumors].

Receptors for Epidermal Growth Factor (EGF) have been identified in different types of tumors and they are often associated with other characteristics which are related to a bad prognosis. A technic has been established to measure membrane receptors in human placenta, which is appropriate for the study of tumors. Preparations of placental membranes were incubated either with increasing amounts (0.1 to 3.0, 10(-9) M) of EGF labeled with 125I (method by saturation) or with 0.2, 10(-9) M labeled EGF and increasing concentrations (0 to 1.6, 10(-9) M) of cold EGF (method by competition). The KD obtained with both technics are not significantly different: 0.85 and 0.77, 10(-9) M respectively, as well as the maximum binding capacity: 5.9 and 4.4 pmol/mg protein respectively. A preliminary study in breast tumors showed that 2 out of 9 contained significant amounts of receptors (58 and 114 fmol/mg protein). One of these two tumors held both estradiol and progesterone receptors. In the other 7 tumors without EGF receptors only one did not contained any estradiol or progesterone receptors. Further studies are needed to evaluate the relationships between EGF/sex hormone receptor status and the degree of breast tumor malignancy.

Breast Neoplasms↗
PubMed1989

Intrapericardial diaphragmatic hernia. A case report.

A case of intrapericardial diaphragmatic hernia caused by blunt trauma is reported. The patient presented with gastric outlet obstruction symptoms. The diagnosis was made pre-operatively by means of plain chest radiography and barium swallow examination. Laparotomy was the surgical approach used. The diaphragmatic defect was too large to close primarily and a Marlex mesh-graft was used. Hydropneumopericardium, pericarditis and cardiac arrhythmias occurred postoperatively and the patient died despite efforts to treat these complications. Because of the rarity of this condition and possible fatal consequences, the important aspects of intrapericardial diaphragmatic hernia are reviewed.

Hernia, Diaphragmatic, Traumatic↗
PubMed1988

Relationship between sex hormones and haemostatic factors in healthy middle-aged men.

Associations of plasma testosterone and estradiol with some haemostatic factors (factor VII activity, fibrinogen, antithrombin III and alpha 2-antiplasmin) were cross-sectionally examined in 251 healthy, middle-aged men participating in the Paris Prospective Study II on risk factors for ischaemic heart disease. Testosterone levels were negatively correlated to factor VII activity and alpha 2-antiplasmin, the main inhibitor of fibrinolysis. No association was found either between testosterone levels and both fibrinogen and antithrombin III, or between estradiol levels and the set of haemostatic variables. The associations between testosterone and both factor VIIc and alpha 2-antiplasmin were independent of HDL-cholesterol, LDL-cholesterol, triglycerides, smoking, alcohol, body mass index and blood pressure. These results suggest that low circulating testosterone levels might be associated with a hypercoagulability state and therefore could contribute to an increased risk of IHD.

Antigens↗
PubMed1988

The effect of cyclosporin A on Trypanosoma musculi infection of mice.

Cyclosporin A treatment of mice infected with Trypanosoma musculi mimicked the effect of T-cell deprivation in increasing the parasitemia and lowering the antibody responses. However, in contrast to T-cell deprivation, cyclosporin A treated mice were still able to clear the parasites from the blood. As expected, T-cell deprived mice were not responsive to cyclosporin A. It is suggested that antibodies against T-independent antigens of the parasite are ineffective in promoting elimination of the trypanosomes. These findings support the importance of T-helper cells in the final elimination of T. musculi from the blood of mice.

Animals↗
PubMed1988

Endocrine and immunological findings in cryptorchid infants.

In cryptorchid infants, significantly decreased mean levels of plasma testosterone and luteinizing hormone (LH) were found between the ages of 30 and 120 days. The levels of testosterone and LH were significantly correlated. No significant difference was found between infants with bilateral or unilateral cryptorchidism. After 120 days there was no longer any significant difference between cryptorchid infants and controls. No significant change in plasma follicle-stimulating hormone (FSH) was found. These data suggest that subnormal secretion of LH could be the primary abnormality in a proportion of boys with so-called common cryptorchidism. Our studies using LH-releasing hormone and human chorionic gonadotropin stimulation tests in older infants and children agree with the data obtained by measurement of basal plasma hormone levels during the first months of life. Anti-gonadotroph antibodies were found in the sera of approximately 50% of the cryptorchid children and infants studied, using an immunofluorescence technique. A study of 17 mothers and their infants gave concordant results in 16 pairs, 9 with and 7 without antibodies. This lead us to speculate on the possible role of maternal autoantibodies as a cause of partial gonadotrophin deficiency in the perinatal period and thus of testicular maldescent. As cryptorchidism is a syndrome, these findings do not mean that a similar mechanism is operative in all cases. However, these data do suggest that alternatives to the classical anatomical view of the descent and nondescent of the testes should be considered.

Age Factors↗
PubMed1987

The connections of the peripeduncular area studied by retrograde and anterograde transport in the rat.

Lying just ventral to the medial geniculate nucleus and dorsal to the cerebral peduncle, the peripeduncular area (PPA) seems to be implicated in the expression of several sexual reflexes in rodents. The aim of the present investigation was to establish the organization of the afferent and efferent projections of the rat's PPA in an attempt to provide a neural substrate corresponding to the behavioral observations. Based on both retrograde and anterograde transport methods, our results suggest that the PPA: receives its main afferent projections from the insulotemporal cortex, basal ganglia, ventromedial and posterior hypothalamic nuclei, zona incerta, inferior colliculus, intermediate and deep layers of the superior colliculus, central gray, cuneiform nucleus, laterodorsal tegmental nucleus, and dorsal nucleus of the lateral lemniscus and, projects essentially to the basal ganglia, ventromedial hypothalamic nucleus, central gray, cuneiform and pedunculopontine nuclei, deep layers of the superior colliculus, inferior colliculus, and dorsal and ventral nuclei of the lateral lemniscus. These findings, indicating that the PPA is connected with the auditory, motor, and limbic systems and with nonspecific diencephalic and mesencephalic centers, are in agreement with the notion that in rodents this area might play a role in the female sexual receptivity (as expressed by lordosis display or ultrasound production) or male mounting behavior.

Animals↗