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Biomedical subjects

M Roger

Publications and source records attributed to M Roger.

At least 19 recordsLinked to original sources

[Pseudoachalasia due to amyloidosis treated by botulinum toxin].

INTRODUCTION: Pseudoachalasia mimics primary achalasia and can provoke serious complications in the elderly. CASE RECORD: A 84 years-old woman had dysphagia with recurrent pneumonia. Pseudoachalasia related to a multifocal primitive amyloidosis was diagnosed. Treatment with botulinum toxin injection during a gastric fibroscopy resulted in clinical improvement, still notable 15 months later. DISCUSSION: Botulinum toxin injection may be a useful tool in treatment of pseudoachalasia due to amyloidosis.

Aged, 80 and over↗

Timing of FSH administration for ovarian stimulation in normo-ovulatory women: comparison of an early or a mid follicular phase initiation of a short-term treatment.

BACKGROUND: In normo-ovulatory infertile women undergoing mild ovarian stimulation out of IVF, FSH stimulation regimen must be carefully adjusted to control the number of recruited follicles and to prevent multiple pregnancies. The aim of this prospective study was to assess the effect of the timing of FSH administration (fixed dose and duration) on the number of large follicles. METHODS: Women were prospectively randomized by means of sealed envelopes to receive daily 112.5 IU recombinant FSH (rFSH), either from cycle day (CD) 2-6 (Group A) or from CD 7-11 (Group B). Hormonal measurements and follicular ultrasound assessments were performed on CD 2, 7 and 12. RESULTS: On CD 12, the development rate of exactly two follicles >or=14 mm in diameter was significantly lower in Group A than in Group B (4% of women versus 42%, P = 0.002). Although the pattern of serum estradiol (E(2)) concentrations in Group A displayed a plateau from CD 7, the cancellation rate for overstimulation (more than three follicles >or=14 mm in diameter) was significantly increased (P = 0.009). CONCLUSIONS: Preventing the closure of the FSH window by mid to late follicular phase FSH administration better fulfils the objective of obtaining a limited number of large follicles than surpassing the FSH threshold by an early administration.

Estradiol↗

Characterization of neural stem cells in the dorsal vagal complex of adult rat by in vivo proliferation labeling and in vitro neurosphere assay.

The dorsal vagal complex, located in the brainstem, is the major integrative center of the autonomic nervous system. By combining in vivo bromodeoxyuridine incorporation and phenotypic immunolabeling, we have previously reported that neurogenesis occurs in the adult rat dorsal vagal complex [Bauer S, Hay M, Amilhon B, Jean A, Moyse E (2005) In vivo neurogenesis in the dorsal vagal complex of the adult rat brainstem. Neuroscience 130:75-90.]. In the present study we asked whether adult dorsal vagal complex contains proliferative and/or neural stem cells. Using Ki-67 immunolabeling and cyclin D1 Western blot, we showed intrinsic cell proliferation in the dorsal vagal complex and its stimulation by vagotomy. Detailed time-course analysis revealed that vagotomy-induced proliferation in the dorsal vagal complex peaked three days after lesion. In order to directly assess the presence of intrinsic stem cells, primary cell cultures from adult rat dorsal vagal complex were performed in the presence of epidermal growth factor and basic fibroblast growth factor (neurosphere assay). A discrete subpopulation of dorsal vagal complex cells proliferated as neurospheres, self-renewed when passaged, and differentiated into neurons, astrocytes and oligodendrocytes. Proliferation and neuron-differentiating potentials of dorsal vagal complex neurospheres were both lower than those of subventricular zone neurospheres from the same rats. The relationship between in vitro neurosphere-forming cells of dorsal vagal complex and in vivo dorsal vagal complex neurogenesis is discussed and remains to be directly addressed. The present data demonstrate the occurrence of neural stem cells in the dorsal vagal complex of adult rat brain.

Animals↗

Spin correlations in the paramagnetic phase and ring exchange in La2CuO4.

Spin correlations in the paramagnetic phase of La(2)CuO(4) have been studied using polarized neutron scattering, with two important results. First, the temperature dependence of the characteristic energy scale of the fluctuations and the amplitude of the neutron structure factor are shown to be in quantitative agreement with the predictions of the quantum nonlinear sigma model. Second, a comparison of a high-temperature series expansion of the equal-time spin correlations with the diffuse neutron intensity provides definitive experimental evidence for ring exchange.

Journal Article↗

Dopamine D3 receptor stimulation promotes the proliferation of cells derived from the post-natal subventricular zone.

In the adult mammalian brain, neural stem cells persist in the subventricular zone (SVZ) where dopamine D3 receptors are expressed. Here, we demonstrate that addition of 1 microm apomorphine increases cell numbers in post-natal SVZ cell cultures. This effect was prevented by a co-treatment with haloperidol, sulpiride or U-99194A, a D3-preferring antagonist, and mimicked by the dopamine D3 receptor selective agonist 7-hydroxy-dipropylaminotetralin (7-OH-DPAT). EC50 values were 4.04 +/- 1.54 nm for apomorphine and 0.63 +/- 0.13 nm for 7-OH-DPAT, which fits the pharmacological profile of the D3 receptor. D3 receptors were detected in SVZ cells by RT-PCR and immunocytochemistry. D3 receptors were expressed in numerous beta-III tubulin immunopositive cells. The fraction of apoptotic nuclei remained unchanged following apomorphine treatment, thus ruling out any possible effect on cell survival. In contrast, proliferation was increased as both the proportion of nuclei incorporating bromo-deoxyuridine and the expression of the cell division marker cyclin D1 were enhanced. These findings provide support for a regulatory role of dopamine over cellular dynamics in post-natal SVZ.

Animals↗

[Investigation, treatment and monitoring of late-onset hypogonadism in males: the official guidelines of the International Society for the Study of the Study of the Aging Male (ISSAM) with comments].

There is increasing interest in the subject of hormone changes in the aging male, which is likely to become particularly important with the expected growth in the population of men over 50. The main concerns at present are androgen decline in the aging male (ADAM), or partial androgen deficiency of the aging male (PADAM), commonly known as the andropause. Although there have been advances in our knowledge of androgen deficiency in the aging male, it is still incomplete, sometimes confusing, and some aspects of androgen replacement therapy remain controversial. The International Society for the Study of the Aging Male (ISSAM) therefore felt it was a good time to review the current situation by publishing a series of practical and official guidelines concerning the diagnosis, treatment and monitoring of late-onset hypogonadism in males. The aim of this study is to present the French translation of these recent international guidelines, and to comment on them.

Aging↗

Osteomalacia cured by surgery.

Oncogenic osteomalacia is an uncommon syndrome characterized by bone pain, proximal muscle weakness, hypophosphatemia, hyperphosphaturia, and a low concentration of 1,25-dihydroxyvitamin D. This syndrome is induced by a tumor, usually benign, of mesenchymal origin and resolves after its excision. We report a case of an oncogenic osteomalacia caused by a small mesenchymal tumor of the tendon sheath of the foot, a localized form of tenosynovial giant cell tumor.

Journal Article↗

Monte Carlo simulations of star-branched polyelectrolyte micelles.

The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte Carlo simulations, using the freely jointed chain model. We have investigated the onset of different regimes corresponding to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb coupling. The Monte Carlo results are in fair agreement with the predictions of Self-Consistent-Field analytical models. We have simulated a real system of diblock copolymer micelles of (sodium-polystyrene-sulfonate)(NaPSS)-(polyethylene-propylene)(PEP) with f = 54 hydrophilic branches of N = 251 monomers at room temperature in salt-free solution. The calculated form factor compares nicely with our neutron scattering data.

Journal Article↗

[Hospitalization criteria for erysipelas: prospective study in 145 cases].

INTRODUCTION: Two recent studies conducted in France among general practitioners have shown that they only hospitalized between 20 to 50 percent of patients with erysipelas seen in private practice. We therefore conducted a hospital-based, prospective study designed to determine the hospitalization criteria for erysipelas, since a number of patients are also hospitalized directly through the emergency department. PATIENTS AND METHODS: This prospective, hospital-based study, included patients hospitalized for clinical diagnosis of erysipelas in 9 centres in north-eastern France. Clinical data were recorded using a standard questionnaire filled-in during the first 72 hours of hospitalization. They included: demographic (name and first name initials, age, sex) and clinical (location of erysipelas) characteristics, as well as the origin of the patient (home, emergency department, other department), the reasons for hospitalization (severity of local or systemic signs, suspicion of deep vein thrombosis, location on the face, age over 60 years, associated diseases, absence of improvement after ambulatory treatment, socioeconomic reasons or on principle hospitalization). Patients hospitalized by (or without) a general practitioner were compared using Chi-2 and Student t tests. RESULTS: One hundred forty-five adults (80 women and 65 men; mean age 61 +/- 20 years) were included in the study: 89 patients (61 p. 100) were hospitalized by a general practitioner whereas 56 (39 percent) went directly to the emergency department. In 128/145 cases (88 p. 100), erysipelas was localized on the lower limbs. The mean number of reasons for hospitalization per patient was of 2.2 +/- 1.2. The most frequent reason for hospitalization was an associated disease (diabetes, obesity, alcoholism, immunodeficiency), present in 77 cases (53 p. 100). Patients hospitalized through a general practitioner were older than those hospitalized directly through the emergency department (68 vs 51 years; p<0.001). Patients hospitalized by a general practitioner more frequently had an erysipelas located on the lower limbs (94 p. 100 vs 79 p. 100; p<0.001) and the mean number of reasons for hospitalization was greater (2.4 vs 1.7; p<0.001), especially suspicion of deep vein thrombosis and elevated mean age. The treatment started during hospitalization was intravenous penicillin G in 67 cases (46 p. 100), oral pristinamycin in 28 cases (19 p. 100) and intravenous or oral amoxicillin in 9 cases (6 p. 100). COMMENTS: This study demonstrates the existence of two distinct courses of hospitalization for erysipelas. Patients hospitalized by a general practitioner were older and their erysipelas more frequently located on the lower limbs and deep vein thrombosis was suspected. Our study also shows the emergence of a population of patients younger and without medical supervision, for whom the general practitioner is replaced by the emergency department of the local hospital. Nevertheless, the most frequent reason for hospitalization in both groups is the existence of an associated disease, possibly responsible for further complications.

Adult↗

Quantum frustration in the "spin liquid" phase of two-dimensional 3He.

We have measured the ultralow temperature and low field magnetic susceptibility of the 4/7 phase of two-dimensional 3He adsorbed on graphite preplated by one layer of 4He. The experiments are performed by progressively adding 4He to the system, thus suppressing in a controlled way the 3He atoms trapped in substrate heterogeneities. This procedure enables us to determine the intrinsic properties of this spin 1/2 model magnet in the zero field limit. The results show quantitatively that the system is strongly frustrated by multiple spin exchange interactions. A characteristic gapped spin liquid behavior is observed at ultralow temperature.

Journal Article↗

Attraction exerted in vivo by grafts of embryonic neocortex on developing thalamic axons.

In a previous study we provided evidence that embryonic (E) day 16 frontal cortical cells grafted into the occipital cortex of newborn rats receive inputs from the ventrolateral (VL) and ventromedial (VM) thalamic nuclei which, normally, project to the frontal cortex (25). The present study was designed to examine further the conditions of development of the thalamic innervation of heterotopic neocortical grafts. We demonstrate that VL/VM axons do not provide transitory aberrant input to the occipital cortex either in intact newborn animals or in rats having received neonatal occipital lesion and subsequent graft of E16 occipital cells. These findings indicate, therefore, that the VL/VM projection to the graft does not result from the stabilization of an initial widespread cortical projection from these thalamic nuclei occurring either spontaneously or in response to the lesion and homotopic transplantation procedures. We also show that the VL/VM projection to frontal-to-occipital grafts develops within a few days posttransplantation and is maintained in adulthood. Finally, this study establishes that most VL/VM axons which enter the grafts are not collaterals of thalamofrontal axons. After having reached the cortex, they proceed caudally primarily within the infragranular layers. The findings of this and previous (25) in vivo studies for the first time provide evidence that developing thalamic axons have the capacity to respond to signals from grafts of E16 cortical cells and are capable of deviating their trajectory to establish contact with the grafts. Only those axons arising from thalamic nuclei appropriate for the cortical locus of origin of the grafted cells respond to the guidance signals. The mechanisms by which the thalamic axons find their way to the graft probably rely on cell-contact signaling and/or long-range attraction exerted by diffusible molecules.

Animals↗

Genetic determinants of pediatric HIV-1 infection: vertical transmission and disease progression among children.

It is very likely that perinatal human immunodeficiency virus type 1 (HIV-1) infection is influenced by a combination of virologic and host factors. A greater understanding of the role played by various risk factors for HIV-1 infection is crucial for the design of new preventive and therapeutic strategies. In recent years, a number of studies have suggested that host genetic factors are important determinants of both the susceptibility to perinatal HIV-1 infection and the subsequent pathogenesis of acquired immunodeficiency syndrome (AIDS). Control of HIV-1 infection involves the processing of specific viral peptides and their presentation to cells of the immune system by highly polymorphic human leukocyte antigen (HLA) alleles. The contribution of multiple HLA class I and II alleles in modulating pediatric HIV/AIDS outcomes has now been confirmed by several independent groups. Penetration of HIV-1 into cells is mediated by interaction between CD4 and chemokine receptors that serve as entry coreceptors. Genetic polymorphisms in chemokine ligand and chemokine receptor genes have recently been associated both with mother-to-child HIV-1 transmission and disease progression in children. These observations suggest a key role for genetic factors in pediatric HIV-1 infection. This article describes the current state of knowledge regarding host genetic influences on pediatric HIV-1 infection and discusses the role of these genes in HIV/AIDS pathogenesis.

Child↗

Dehydroepiandrosterone (DHEA), DHEA sulfate, and aging: contribution of the DHEAge Study to a sociobiomedical issue.

The secretion and the blood levels of the adrenal steroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) decrease profoundly with age, and the question is posed whether administration of the steroid to compensate for the decline counteracts defects associated with aging. The commercial availability of DHEA outside the regular pharmaceutical-medical network in the United States creates a real public health problem that may be resolved only by appropriate long-term clinical trials in elderly men and women. Two hundred and eighty healthy individuals (women and men 60-79 years old) were given DHEA, 50 mg, or placebo, orally, daily for a year in a double-blind, placebo-controlled study. No potentially harmful accumulation of DHEAS and active steroids was recorded. Besides the reestablishment of a "young" concentration of DHEAS, a small increase of testosterone and estradiol was noted, particularly in women, and may be involved in the significantly demonstrated physiological-clinical manifestations here reported. Bone turnover improved selectively in women >70 years old, as assessed by the dual-energy x-ray absorptiometry (DEXA) technique and the decrease of osteoclastic activity. A significant increase in most libido parameters was also found in these older women. Improvement of the skin status was observed, particularly in women, in terms of hydration, epidermal thickness, sebum production, and pigmentation. A number of biological indices confirmed the lack of harmful consequences of this 50 mg/day DHEA administration over one year, also indicating that this kind of replacement therapy normalized some effects of aging, but does not create "supermen/women" (doping).

Absorptiometry, Photon↗

[Mycobacterium xenopi osteoarthritis of the ankle in a patient followed for psoriatic rheumatism].

BACKGROUND: Mycobacterium xenopi is an uncommon cause of osteoarticular sepsis. However, a recent series of M. xenopi spondylodiscitis emphasizes the potential risk after invasive procedures. CASE REPORT: A 33-year-old woman was followed for psoriasis rheumatoid arthritis. She had undergone several exploratory procedures including arthroscopy of the left ankle for invalidating joint disease. In 1999, M. xenopi arthritis and osteomyelitis was diagnosis in this joint. DISCUSSION: Sterilization and maintenance of surgical instruments must abide by rigorously controlled strict protocols. The benefit/risk ratio of invasive procedures in debilitated joints should be more precisely evaluated. Specific and repeated sample cultures should be performed to search for mycobacteria in all bone and joint infections, particularly in case of prior invasive procedures.

Adult↗