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Biomedical subjects

M Roger

Publications and source records attributed to M Roger.

At least 19 recordsLinked to original sources
PubMed1992

Topographical organization of the projections from physiologically identified areas of the motor cortex to the striatum in the rat.

The present study was undertaken to determine in the rat the topography of the neostriatal projections originating from the motor cortex. For that purpose, anterograde tracers (Phaseolus vulgaris leucoagglutinin: PHA-L; wheat germ agglutinin conjugated to horseradish peroxidase: WGA-HRP) were deposited in discrete cortical sites physiologically identified by microstimulation. Five major motor areas were considered in this study: the rostral (RFL) and caudal (CFL) forelimb areas, the hindlimb (HL) area, the vibrissae motor-frontal eye field (V-FEF) region and the jaw, lips and tongue (JLT) area (according to the nomenclature of Neafsey et al.). The results indicate that functionally different regions of the motor cortex project to different sectors of the caudate putamen (CPU). All 3 distinct limb areas RFL, CFL and HL project to the dorsolateral quarter of the CPU, V-FEF area projects to the dorsomedial quarter, whereas the JLT area projects to the ventrolateral quarter. The pattern of terminal labeling is relatively consistent, whatever the cortical area in which the tracer is deposited. This pattern is characterized by the presence of two or more labeled bands which are obliquely oriented along a ventrolateral-dorsomedial axis. Control experiments were also undertaken in which a retrograde tracer (WGA-HRP) was deposited in various neostriatal loci. The results are congruent with the findings of the anterograde study and further indicate that a given neostriatal sector receives projections from cytoarchitectonically different but functionally related regions of the neocortex. The somatotopic features of both motor and somatosensory corticostriatal projections appear to be in register. In addition, the striatal distribution of motor cortical fibers was compared in 6 experimental cases to the compartmental subdivision of the striatum in patches and matrix, following immunohistochemical localization of calbindin 28 kDa. The calbindin-immunoreactivity is extremely weak in the dorsolateral sector but is higher in the central and ventrolateral parts of the CPU. In these deep striatal regions receiving fibers from V-FEF, JLT and, to a lesser extent, from the limb areas, the cortical fibers are mostly directed to the matrix. The band-like organization of the projection from the motor cortex is correlated to the patch-matrix organization. The patches correspond to the bands of low density of terminal fibers and the matrix to the bands of high terminal density. The present results provide an anatomical basis to both electrophysiological and behavioral observations suggesting that functional distinctions can be established between subregions of the striatum.

Animals↗
PubMed1992

Features of insulin-resistance syndrome in men from French Caribbean Islands. The Telecom Study.

The prevalence of diabetes is known to be high in the West Indies, whereas CVD seems relatively rare. This apparently contradicts the existence of the insulin-resistance syndrome, a cluster of metabolic abnormalities supposedly favoring both diabetes and cardiovascular complications. To address the question of whether this contradiction could be accounted for by specific features of this syndrome, we compared 1505 Caucasian and 181 Afro-Caribbean men, all participants in the French Telecom Study. The Afro-Caribbeans were of the same age and had the same BMI as the Caucasians; they also had significantly higher subscapular skin-fold thickness and fasting insulin level, but similar BP and blood glucose level, and significantly lower plasma triglyceride level. Thus, although some features of the insulin-resistance syndrome were present (central adiposity and high insulin levels), none of the associated metabolic abnormalities were present. However, within the Afro-Caribbean group, subjects with plasma insulin concentrations above the median (> 52 pM) had higher mean BP and glucose and triglyceride levels compared with subjects with insulin concentrations < or = 52 pM (P < 0.001). After adjustment for age and BMI, these differences, though smaller, still were statistically significant. These findings confirm that higher insulin concentrations are associated with higher levels of potentially atherogenic and diabetogenic metabolic parameters. However, depending on ethnic origin, the mean levels of these parameters seem to be different, with the consequence that, even if they are elevated with increasing insulin levels, they may not reach values high enough to determine a substantial risk of disease.

Adult↗
PubMed1992

[Connections of the posterior region of the thalamus in rats].

Using retrograde and anterograde tracing methods we have studied in the posterior region of the thalamus of the rat the distribution of: (1) the terminal fields of the main afferents arising from somatosensory centers (dorsal column nuclei, interpolar trigeminal subnucleus, somatosensory cortex), motor centers (red nucleus, motor cortex) and multimodal structures (deep layers of the superior colliculus, zona incerta, cingular cortex) and of (2) the neurons giving rise to the main efferents towards the sensorimotor cortex, the red nucleus, the deep layers of the superior colliculus and the zone incerta. The overlap of the retrograde and anterograde labeling reveals a relatively homogeneous region. Considering however the cortical connections, three different subdivisions can be distinguished: a caudal pole completely devoid of cortical connections, a medial subdivision receiving cortical afferents from the sensorimotor and cingulate cortices and a rostral pole reciprocally connected with the sensorimotor cortex. Therefore the rostral pole would be the only part of this region which should be included in the thalamus.

Afferent Pathways↗
PubMed1979

Measurement of plasma human chorionic gonadotropin (hCG) and beta-hCG activities in the late luteal phase: evidence of the occurrence of spontaneous menstrual abortions in infertile women.

Plasma luteinizing hormone (LH-human chorionic gonadotropin (hCG) and beta-hCG activities were measured during the late luteal phase in 321 cycles of 147 infertile women. In 71 cycles the hCG measurement permitted the diagnosis of pregnancy between the 10th and 14th days after the thermal nadir. The slope of the regression line derived from hCG levels during the first 22 days of pregnancy was significantly lower in pregnancies which aborted before the 60th day than in normal pregnancies (P less than 0.01). Among 72 cycles ended by apparently normal menses which exhibited an LH-hCG activity at least equal to 7 mIU of hCG/ml during the late luteal phase, the beta-hCG activity was measured in 49 cycles during which hCG had not been given. Significant beta-hCG activity (greater than or equal to 4 mIU of hCG/ml) was detected in 19 cases. This finding supports the assumption that secretory trophoblastic tissue had been present and that spontaneous menstrual abortions had occurred in these women.

Abortion, Spontaneous↗
PubMed1979

Longitudinal study of plasma testosterone in male pseudohermaphrodites during early infancy.

Plasma testosterone was longitudinally studied during the first months of life in 7 XY infants with male pseudohermaphroditism. In two, the physiological postnatal rise of plasma testosterone was absent or blunted. A combined adrenal and testicular enzymatic defect was demonstrated in these two boys. In 5, a normal postnatal testosterone rise demonstrated a normal Leydig cell function. The longitudinal study of the physiologic postnatal rise of testosterone may be useful to distinguish secretory defects from responsiveness abnormalities thus improving the choice of gender in male pseudohermaphrodites.

Age Factors↗
PubMed1979

[Adrenocortical function in hyperprolactinemia. The study of glucocorticoids, mineralocorticoids and androgens in chronic and acute hyperprolactinemias (author's transl)].

Glucocorticoids, mineralocorticoids, and adrenal androgens were studied in 3 groups of patients: control subjects (group I), hyperprolactinemic subjects (group II) and miscellaneous patients including chromophobe adenomas and normalized hyperprolactinemic subjects treated with Bromocriptine (group III). All the patients were studied in the basal state and under various conditions: Metyrapone, ACTH, TRH for glucocorticoids, ACTH, TRH, saline perfusion for mineralocorticoids, ACTH and TRH for androgens. It is concluded that: the adrenal secretion of glucocorticoids, mineralocorticoids and androgens is not altered under basal conditions in chronic hyperprolactinemia nor during dynamic tests in chronic hyperprolactinemia (prolactin adenoma) nor in acute hyperprolactinemia (induced by TRH).

Acute Disease↗
PubMed1978

[Controlled trial of levamisole in rheumatoid arthritis. Clinical and immunological study of 22 cases (author's transl)].

The results of a controlled trial in 22 patients indicated that levamisole, administered in a dose of 150 mg per day for 2 months, was more effective than a placebo on the clinical symptoms and signs of rheumatoid arthritis. Side effects were seen in 8 of the 12 patients treated with levamisole. They necessitated the premature interruption of treatment in three, but were never serious (no cases of agranulocytosis were seen). In the group treated with levamisole, there was a slight decrease in sedimentation rate, a significant fall in levels of the C3 fraction of serum complement and of circulating immune complexes (detected by polyethylene glycol), and a significant increase in cutaneous reaction to tuberculin and to candidin. By contrast, there were no significant variations in levels of rheumatoid factor, serum immunoglobulins, C4 fraction of complement, lymphocyte transformation indices in the presence of six dilutions of phytohaemagglutinin, nor in the percentages of T and B lymphocytes. The effectiveness of levamisole in rheumatoid arthritis would appear to be demonstrated, but its mode of action remains open to discussion, in the absence of any definite correlation between therapeutic activity and the immunostimulant effects of the drug.

Antigen-Antibody Complex↗
PubMed1978

Endocrine studies in male pseudohermaphroditism in childhood and adolescence.

The clinical and endocrine features of fifty cases of male pseudohermaphroditism and XY karyotype aged from 6 months to 20 years have been studied. Thirty-two subjects were pre-pubertal and eighteen, of whom ten developed gynaecomastia, were pubertal. A definite aetiology was established in 12%. 4% had deficient testosterone biosynthesis and 8% mixed gonadal dysgenesis. In the remaining 88% an aetiology of androgen unresponsiveness at the target areas is suggested. Hormonal investigations in these subjects showed that before puberty basal plasma testosterone and oestradiol were slightly but significantly elevated, whereas testosterone response to stimulation with human chorionic gonadotrophin was significantly diminished. In the pubertal subjects basal plasma testosterone, oestradiol, serum binding capacity of testosterone-oestradiol binding globulin and basal plasma LH were significantly elevated. These hormonal features in pubertal or post-pubertal male pseudohermaphrodites appear to be characteristic of androgen unresponsiveness. The presence in addition of elevated basal plasma testosterone and oestradiol in the pre-pubertal subjects suggest that some of these findings may be presented from early childhood.

Adolescent↗
PubMed1978

Variations of serum testosterone estradiol binding globulin (TeBG) binding capacity in infants during the first year of life.

Serum TeBG binding capacity was measured in 8 cord blood samples, and in peripheral venous blood from 39 male and 31 female infants aged from 1 day to 1 year. In cord blood, TeBG binding capacities were low (1.27 +/- 0.3 microgram/100 ml) with no sex difference. In male infants, TeBG binding capacities increased progressively from birth to 3 months, before decreasing to reach the normal prepubertal level at 6 months. Individual values ranged between 1.16 and 14.5 microgram/100 ml and were significantly correlated with plasma testosterone (r = 0.671, 95% confidence limits 0.440 to 0.818, p less than 0.005) and estradiol (r = 0.734, 95% confidence limits 0.121 to 0.942, p less than 0.01) levels. In female infants, individual values ranged between 1.17 and 14.5 microgram/100 ml, without correlation with age or plasma estradiol level. In male infants the data suggest a positive control ot TeGB binding capacity by estrogens, the negative effect of testosterone being delayed until after the 3rd month of age. In girls, the lack of correlation between TeBG and estradiol can probably be explained by rapid variations of plasma estradiol levels.

Age Factors↗
PubMed1978

Reduced post-natal rise of testosterone in plasma of cryptorchid infants.

Plasma testosterone has been studied in 31 full-term male infants born with bilaterally undescended testes (14) or unilaterally undescended testis (17). From 10 to 89 days after birth, the post-natal testosterone rise was significantly lower in the 18 infants who remained cryptorchid at 4 months than in the 13 who underwent spontaneous testicular descensus and in the normal controls. Blunted post-natal Leydig cell secretion in cryptorchids may relate to a primary LH defect and could contribute to the impairment of both testicular descensus and maturation.

Cryptorchidism↗
PubMed1978

[Endocrine data in cryptorchism].

Endocrine evaluation with LH-RH (0.1 mg/m2) and chorionic gonadotrophin (HCG 3 X 1,500 I.U.) in 154 cryptorchid boys aged 1 month to 15 years showed a decrease of LH pituitary secretion and Leydig-cells response to HCG in prepubertal and early pubertal patients. These deficiencies were positively correlated. Partial and at least transient descent of cryptorchid testis or testes has been obtained in 87 of 265 patients treated with HCG (3 to 9 X 1,500 I.U.). Plasma testosterone after HCG 3 X 1,500 I.U. was less increased in patients whose cryptorchid testis or testes descended after 9 X 1,500 I.U. than in those whose testes remained undescended. These data suggest that a partial, early and transient deficiency of pituitary LH secretion may be responsible for testicular maldescent in part of cryptorchid boys.

Adolescent↗
PubMed1977

[The course of hydatidiform moles, followed by the radio-immunological estimation of choriogonadotrophin (author's transl)].

The evolution of 50 hydatidiform moles was followed through repeated radioimmunoassays of choriogonadotropin (hCG), either in urine or plasma. In 37 cases a spontaneous regular decrease was observed, but it generally slowed down after the first week. In fact, only 30% of the total number of moles examined cleared up spontaneously within a month and 54% within 8 weeks. In 12 cases a diagnosis of retention of trophoblastic tissue was made: three times during the first month of evolution on the basis of a stagnation of the decreasing curve. In the 9 cases without radioimmunoassay of hCG between the 10th and 40th days after evacuation, the diagnosis was not made until after two months. The specific assay of hCG with an anti beta-hCG antiserum enables the resolution of diagnostic problems raised by the cross-reaction of hypopituitary LH when using the classic antiserum and particularly the differential diagnosis between the retention of trophoblastic tissue and a beginning pregnancy immediately following a mole, or a high level of LH after castration.

Chorionic Gonadotropin↗
PubMed1977

Activity of the crayfish caudal photoreceptor submitted to a conditioning paradigm.

The activity of the crayfish caudal photoreceptor (Ph) was studied during the application of a classical conditioning paradigm. This cell is a primary photoreceptor and, at the same time, a secondary neuron in the mechanoreceptive pathway. The electrical stimulation of afferent mechanoreceptor fibers, the analog of the conditioned stimulus (ACS), produced a slight increase in the Ph firing rate. The photic stimulation, the analog of the unconditioned stimulus (AUS), produced a marked increase in the Ph firing rate. After ACS-AUS pairing, a decrease in the Ph firing rate appeared during the ACS-AUS interval, and it was considered the analog of the conditioned response (ACR). This inhibitory response gradually vanished during extinction. The application of ACS or AUS series alone did not produce a response similar to the ACR, this excluding sensitization as a possible cuase. The ACR meets several conventional criteria accepted in learning, supporting the idea that the crayfish caudal photoreceptor is part of a small neuronal network able to learn in the isolated nerve cord preparation.

Animals↗
PubMed1977

Mismatch excision and possible polarity effects result in preferred deoxyribonucleic acid strand of integration in pneumococcal transformation.

Heteroduplex deoxyribonucleic acid molecules having a drug resistance marker on one strand and its wild-type allele on the other have been used as donors in pneumococcal transformation. Opposite strands are not equally effective in producing transformants, and this strand bias is not the same, either in direction or magnitude, for various different genetic markers. Selective excision of mismatched base pairs is probably responsible for the large differences in strand efficiency seen with discriminating (hex+) strains, for when the recipient is nondiscriminating (hex-), and therefore presumably lacking an excision enzyme system, strand bias is drastically reduced or altered. The evidence also indicates that excision occurs after integration, as it is provoked by specific donor-recipient mismatch and not by the same mismatch when introduced within donor heteroduplex molecules. Excision can extend to include a neighboring linked marker which would otherwise not be excised, thus altering its intrinsic strand bias as well as its efficiency in transformation. There is a small bias in relative strand efficiency for some markers, not caused by mismatch excision, which perhaps is due to polarity in the integration process itself.

Aminopterin↗
PubMed1977

Pituitary LH and FSH and testosterone secretion in infants with undescended testes.

Twelve male infants with undescended testes (5 bilaterally, 7 unilaterally) were studied between the ages of 1 week and 11 months. As in older pre-pubertal cryptorchid boys, a significant decrease of the LH response to LH-RH test was found, while basal plasma levels of gonadotrophins and FSH response to LH-RH were normal. Plasma testosterone levels were in the normal range, and Leydig cells responded to stimulation by HCG, the degree of this response being significantly and positively correlated to the LH peak elicited by LH-RH. It may be concluded that some early defect of the pituitary-Leydig cell axis is associated with undescended testis.

Chorionic Gonadotropin↗
PubMed1977

Correlation of pituitary and testicular responses to stimulation tests in cryptorchid children.

LH-RH test and HCG stimulation test were performed in 154 cryptorchid boys aged 1 month to 15 years (64 unilateral and 90 bilateral). Basal plasma LH levels and LH response to LH-RH were significantly lower from infancy to early puberty in cryptorchids compared with controls. Basal FSH levels and FSH response to LH-RH were normal. The post-HCG rise of plasma testosterone was reduced until mid-puberty. A significant positive correlation was found between post-HCG testosterone levels and pre- and post-LH-RH levels of LH. This correlation suggests that testicular maldescent and the decreased ability of Leydig cells to respond to a short course of HCG may result from an early defect or a delay of pituitary LH secretion.

Adolescent↗