PubMed Health⌕ Search

Biomedical subjects

D Leroy

Publications and source records attributed to D Leroy.

At least 19 recordsLinked to original sources
PubMed2002

Effect of mandibular orthopedic repositioning appliance on kinematic pattern in golf swing.

Experience has shown that repositioning the mandible may have an influence on the athletic performance. Many athletes with or without occlusal problems are now using mandibular orthopedic repositioning appliance (MORA) supposedly to optimize their performance. In golf, the players do not have any direct opponent and they have different clubs to reach various distances. Therefore, an automatic swing permits the uncertainty of the movement to be restricted. The aim of this study was to analyze if the use of the MORA could have an effect on the stability of the kinematic pattern in golf swing, connected to the capacity of the golfers to reproduce their swing from kinematic perspective. The measures of kinematic data have been established with the optoelectronic system VICON (Oxford's Metrix, Oxford, UK) with five cameras operating at 50 frames per second. Measurements of the speed of the ball at impact were obtained with a radar (Bridgestone HD.01, Science eye, USA). Six professional (current handicap ranging from 0 to 4) right-handed golfers participated in the study. Six MORA were made and adjusted to fit each player. Each golfer performed five swings without mouthpiece and five with the MORA. The results of this study show that there was no difference related to the MORA on kinematic pattern of the golf swing. Moreover, there were significant differences concerning the ball speed at the impact, among the two test conditions, with or without the appliance (p < 0.03). The percentage of variability indicates that the speed with MORA was more regular than the speed without the appliance.

Adolescent↗
PubMed2001

Analysis of etoposide binding to subdomains of human DNA topoisomerase II alpha in the absence of DNA.

Epipodophyllotoxins are effective anti-tumor drugs that inhibit eukaryotic DNA topoisomerase II by trapping the enzyme in a covalent complex with DNA. We show that both the recombinant N-terminal ATPase domain and the B'A' core domain of human topoisomerase IIalpha (htopoIIalpha) bind radiolabeled etoposide specifically, even in the absence of DNA. The addition of ATP impairs etoposide binding to the holoenzyme and the N-terminal domain, but not to the core domain. To see if this interference resembles that between novobiocin and ATP in the bacterial GyrB subunit, we modeled the structure of the N-terminal domain of htopoIIalpha and performed molecular docking analysis with etoposide. Mutagenesis of critical amino acids, predicted to stabilize the drug within the N-terminal domain, reveals a less efficient binding of etoposide to the mutated proteins as monitored by direct drug binding assays, although the binding of ATP is not affected.

Adenosine Triphosphate↗
PubMed2001

Interstitial granulomatous dermatitis with cutaneous cords and arthritis: a disorder associated with autoantibodies.

Interstitial granulomatous dermatitis with arthritis is a new entity characterized by linear or arciform subcutaneous cords. We describe a patient presenting with typical cutaneous lesions extending from the anterior and posterior part of the axillae to the flank. The lesions had been present for 6 years with flares and remission. Histopathologic examination revealed a bandlike infiltrate of histiocytes in the reticular dermis with focal areas of palisading around necrotic collagen bundles. A few atypical histiocytes were also present. As previously described, it was associated with serologic findings of an autoimmune disease, especially high titers of anti-DNA antibodies. The possible inclusion of the interstitial granulomatous dermatitis in the continuous spectrum of the palisaded neutrophilic and granulomatous dermatitis of immune complex disease is also discussed.

Aged↗
PubMed2001

Microwave strategy for improving the simultaneous detection of estrogen receptor and galanin receptor mRNA in the rat hypothalamus.

In a attempt to improve the sensitivity of the simultaneous use of immunohistochemistry (IHC) with estrogen receptor (ER) and in situ hybridization (ISH) with a neuropeptide receptor, we first applied an existing microwave (MW) irradiation protocol for immunohistochemical detection of the estrogen receptor in frozen brain sections. Regions of interest were the preoptic area and the arcuate nucleus of the hypothalamus. ER signal was effective only after MW heating of sections in the two regions. Control sections without pretreatment exhibited no staining for ER. Second, the MW protocol was applied in a novel procedure that consists of evaluation of the expression of the galanin receptor mRNA with a radioactive riboprobe after MW pretreatment. The galanin receptor mRNA signal intensity obtained after heating was quantitatively at least as good or significantly increased according to the region, with no discernible loss of tissue morphology. Finally, we describe a novel application of MW pretreatment on the same frozen section processed with ER antibody and a radioactive galanin receptor riboprobe. The stainings for estrogen and galanin receptors were intense in many cells of the preoptic area, with very low background. These results show that both IHC and ISH can be significantly improved by subjecting frozen sections to MW heating before the double labeling. This approach may provide a potential method to answer the important question of whether or not estrogen has a direct action on the expression of a peptide receptor. (J Histochem Cytochem 49:901-910, 2001)

Animals↗
PubMed2001

[Hydroa vacciniforme: dietary fish oil].

BACKGROUND: Hydroa vaccinniforme is a highly uncommon photodermatosis acquired in childhood. The clinical course is dominated by the risk of varioliform scars. Numerous treatments have been proposed with variable efficacy. One recent open study suggested dietary fish oil could be useful. We report a case of hydroa vacciniforme treated successfully with dietary fish oil (Maxepa(R)). CASE REPORT: A 15-year-old girl consulted in May 1988 for vesiculobullous lesions typical of hydroa vacciniforme in photo-exposed areas. Anti-malaria drugs and photoprotection had been used for several years without success. Maxepa(R) was introduced in June 1998 and was followed by regression of the lesions within a few weeks despite the summer season. The treatment was interrupted at the patient's request due to fetid breath. Reintroduction of Maxepa(R) in April 1999 after an episode of recurrent lesions, again led to total resolution of the lesions within three weeks. DISCUSSION: Hydroa vacciniforme is an exceptional photodermatosis of uncertain etiology. It may possibly be related to an abnormal sensitivity to ultraviolet A. Fish oil rich in 3-omega polyunsaturated fatty acids would reduce the local inflammation triggered by sun exposure. Recent studies have demonstrated that dietary fish oil can increase the level of 3-omega polyunsaturated fatty acids in the epidermis and reduce the level of prostaglandins in the skin. Our case would appear to confirm the contribution of dietary fish oil to treatment despite the poor tolerance due to fetid breath.

Adolescent↗
PubMed2000

Microwave pretreatment of sections to improve the immunocytochemical detection of progesterone receptors in the guinea pig hypothalamus.

The goal of this study was to evaluate the effects of microwave heat on immunocytochemical staining for progesterone receptors (PR) in frozen sections and in paraffin-embedded sections of guinea pig brain using an antibody previously shown to successfully stain only frozen sections of formalin-fixed materials. A simple, reliable and sensitive retrieval method has been adapted based on microwave irradiation of sections in citrate solution prior to incubation with the anti-PR antibody. Different pH values (3.0, 6.0 and 8.5) of the citrate buffer were tested and the pH at 6.0 was found to give the best results. PR-like immunoreactivity was markedly increased in frozen sections exposed to microwave heating compared with untreated tissue. The integrity of the tissue was not affected by this treatment and specific nuclear immunoreactivity for PR was detected in hypothalamic neurons. Staining of paraffin-embedded sections without microwave pretreatment yielded negative results while irradiation of sections enabled the labeling of hypothalamic regions known to contain progesterone binding sites. Immunocytochemical staining did not reveal any significant difference in the number of PR-immunoreactive neurons between frozen tissue compared with paraffin-embedded tissue. The results indicate that microwave irradiation can unveil PR antigenicity in sections of paraffin-embedded brain and enhances immunostaining in sections of frozen tissue.

Animals↗
PubMed2000

Differential effects of colchicine on the induction of nitric oxide synthase in neurons containing progesterone receptors of the guinea pig hypothalamus.

Using nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPHd) histochemistry, we analyzed the effects of an intracerebroventricular injection of colchicine on the activity of neuronal nitric oxide synthase in the hypothalamic nuclei of intact and ovariectomized estradiol-primed guinea pigs. We also examined the effects of colchicine on the immunocytochemical colocalization of nitric oxide synthase with the progesterone receptor in the ventrolateral nucleus, a key region in the control of sexual behavior. Treatment with colchicine resulted in a significant increase in the number of NADPHd-positive neurons in the ventrolateral nucleus in intact as well as in ovariectomized estradiol-primed animals, whereas in the other hypothalamic regions analyzed (preoptic area, paraventricular nucleus and posterior arcuate nucleus), the enzymatic activity remained unchanged. Quantitative analysis showed a significantly greater number of NADPHd-positive cells in the medial and the posterior aspects of the ventrolateral nucleus of colchicine-treated guinea pigs compared to the control group. In the caudal subdivision of this nucleus, colchicine induced nitric oxide synthase in the target cells for progesterone. These results suggest that neuronal nitric oxide synthase activity in the hypothalamus is affected by colchicine in a region-specific manner and especially in the ventrolateral nucleus, which is involved in progesterone-facilitated lordosis.

Animals↗
PubMed2000

Polychromatic phototest as a prognostic tool for polymorphic light eruption.

BACKGROUND: Diagnosis of polymorphic light eruption (PLE) is based on the patient's history, the morphology of the lesions and the results of phototesting. Skin lesions of PLE can be provoked by repetitive UVB or UVA irradiation. However, about 20% of the patients with PLE have negative phototests. As 24% of the patients with PLE go into remission, it was of interest to search for a link between the results of the phototests and the evolution of the photodermatosis. METHODS: Forty patients with PLE were recruited and repetitive phototests were performed. To ensure a good reproducibility of the phototests, one to three phototests were performed on each patient at different stages of the disease including the period when the PLE had gone into remission. RESULTS: Except for one patient, there was a good reproducibility of the repetitive polychromatic phototests: in each patient, the tests remained positive or negative throughout the disease. After long-term follow-up, two different subgroups were identified: 30 patients with active PLE and 10 patients in remission. There were no clinical differences between these two groups apart from the age of onset and the clinical lesions of the PLE. PLE began at an earlier age in the patients in remission and presented mainly with a plaque-type eruption. In total, 52.5% of the patients had at least one positive polychromatic phototest. Phototests were positive only in patients with active disease. All the patients in remission had negative phototests. CONCLUSIONS: Repetitive phototests could be a prognostic marker for PLE. Two subtypes of PLE were identified on the basis of phototest results: the benign form of PLE with negative phototests, which tends to go into remission, and the more severe and more chronic PLE, with positive phototests.

Adult↗
PubMed2000

Photoscratch testing in systemic drug-induced photosensitivity.

Because of numerous false-negative results, photopatch testing is seldom relevant in systemic drug-induced photosensitivity. These false-negative photopatch test results can be attributed to the inability of the drug to penetrate into the epidermis. In order to enhance the penetration of the tested drug into the epidermis, some authors proposed to breach the cutaneous barrier. We performed a prospective study comparing photopatch and photoscratch testing. Fifteen patients presenting with a systemic drug-induced photosensitivity, proved by a favourable outcome after discontinuing the drug, were tested. For each drug, photopatch and photoscratch tests were performed. Two-thirds of the patients had negative photopatch and photoscratch tests with the suspected drugs. Photopatch and photoscratch tests were positive and relevant, respectively, in 3 and 4 patients. Photoscratch tests induced more false-positive results due to irritation confirmed on control subjects. Our study proves that photoscratch tests do not change the sensitivity of phototesting.

Adult↗
PubMed2000

Spatial and temporal gait variable differences between basketball, swimming and soccer players.

The gait variables of 10 swimmers, 10 basketball players, and 16 soccer players were compared. They were all male and right-handed. There was no statistical difference between the three groups in age, weight and height. Spatial and temporal gait variables were measured with the Bessou gait analyzer. In the swimmers group, the gait variables of the right side were not statistically different from those of the left side. The right propulsion double support duration, right cycle duration, and right late swing phase duration were respectively longer than those on the left side for the basketball players. The right propulsion double support duration, right step length, and right late swing phase duration were higher than those on the left side for the soccer players. Moreover, a discriminant analysis performed with the gait variables permitted significant differentiation between the three groups. In conclusion, both basketball and soccer players presented asymmetrical gait variables, that have never been previously reported in normal subjects, or in swimmers. These results suggest that the anticipatory postural adjustments programmed to be used just before a jump or a shoot influence the motor program of the spontaneous locomotion. These gait asymmetries could also be due to asymmetric muscle development.

Adult↗
PubMed2000

Transcription of meiotic cell cycle and terminal differentiation genes depends on a conserved chromatin associated protein, whose nuclear localisation is regulated.

The Drosophila always early (aly) gene coordinately regulates meiotic cell cycle progression and terminal differentiation during male gametogenesis. aly is required for transcription of key G2-M cell cycle control genes and of spermatid differentiation genes, and for maintenance of normal chromatin structure in primary spermatocytes. We show that aly encodes a homologue of the Caenorhabditis elegans gene lin-9, a negative regulator of vulval development that acts in the same SynMuvB genetic pathway as the LIN-35 Rb-like protein. The aly gene family is conserved from plants to humans. Aly protein is both cytoplasmic and nuclear in early primary spermatocytes, then resolves to a chromatin-associated pattern. It remains cytoplasmic in a loss-of-function missense allele, suggesting that nuclear localisation is critical for Aly function, and that other factors may alter Aly activity by controlling its subcellular localisation. MAPK activation occurs normally in aly mutant testes. Therefore aly, and by inference lin-9, act in parallel to, or downstream of, activation of MAPK by the RTK-Ras signalling pathway. We favour a model where aly may regulate cell cycle progression and terminal differentiation during male gametogenesis by regulating chromatin conformation in primary spermatocytes.

Amino Acid Sequence↗
PubMed2000

Uncoupling of cell proliferation and differentiation activities of basic fibroblast growth factor.

FGF-2 exerts its pleiotropic effects on cell growth and differentiation by interacting with specific cell surface receptors. In addition, exogenously added FGF-2 is translocated from outside the cell to the nucleus during G1-S transition. In this study, we show that a single point mutation in FGF-2 (substitution of residue serine 117 by alanine) is sufficient to drastically reduce its mitogenic activity without affecting its differentiation properties. The FGF-2(S117A) mutant binds to and activates tyrosine kinase receptors and induces MAPK and p70S6K activation as strongly as the wild-type FGF-2. We demonstrate that this mutant enters NIH3T3 cells, is translocated to the nucleus, and is phosphorylated similar to the wild-type growth factor. This suggests that FGF-2 mitogenic activity may require, in addition to signaling through cell surface receptors and nuclear translocation, activation of nuclear targets. We have previously shown that, in vitro, FGF-2 directly stimulates the activity of the casein kinase 2 (CK2), a ubiquitous serine/threonine kinase involved in the control of cell proliferation. We report that, in vivo, FGF-2(WT) transiently interacts with CK2 and stimulates its activity in the nucleus during G1-S transition in NIH3T3 cells. In contrast, the FGF-2(S117A) mutant fails to interact with CK2. Thus, our results show that FGF-2 mitogenic and differentiation activities can be dissociated by a single point mutation and that CK2 may be a new nuclear effector involved in FGF-2 mitogenic activity.-Bailly, K., Soulet, F., Leroy, D., Amalric, F., Bouche, G. Uncoupling of cell proliferation and differentiation activities of basic fibroblast growth factor (FGF-2).

3T3 Cells↗
PubMed2000

[Localized bullous pemphigoid following radiotherapy].

BACKGROUND: Bullous pemphigoid is the most frequent autoimmune blistering dermatologic disease. Induction of pemphigoid has been observed after administration of certain drugs but also after various irradiation procedures. We report a case of pemphigoid strictly confined to the irradiated area. CASE REPORT: A 66-year-old woman had been irradiated 16 years before because of a breast carcinoma. She presented with a blistering rash strictly confined to the irradiated area. The diagnosis of pemphigoid was confirmed with pathologic examination, direct immunofluorescence, direct immunofluorescence of sodium chloride-separated skin, electron microscopy and immunoelectron microscopy. Indirect immunofluorescence and serum immunoblot were also positive. The patient was successfully treated with topical steroids. DISCUSSION: The location on the area of radiotherapy and the limited character of lesions were unusual. A few cases of pemphigoid strictly localized to the area of radiotherapy have been published. However, in our case, only direct immunofluorescence and immunoelectron microscopy reliably confirmed the diagnosis. The unusual location of this pemphigoid is not due to the regional variation in the expression of the antigen. Other hypotheses concerning the pathogenesis of localized pemphigoid should be examined.

Adenocarcinoma↗
PubMed1999

Functional conservation and cell cycle localization of the Nhp2 core component of H + ACA snoRNPs in fission and budding yeasts.

We report the identification of a novel nucleolar protein from fission yeast, p17(nhp2), which is homologous to the recently identified Nhp2p core component of H+ACA snoRNPs in Saccharomyces cerevisiae. We show that the fission yeast p17(nhp2) localizes to the nucleolus in live S. cerevisiae or Schizosaccharomyces pombe cells and is functionally conserved since the fission yeast gene can complement a deletion of the NHP2 gene in budding yeast. Analysis of p17(nhp2) during the mitotic cell cycles of living fission and budding yeast cells shows that this protein, and by implication H+ACA snoRNPs, remains localized with nucleolar material during mitosis, although the gross organization of partitioning of p17(nhp2) during anaphase is different in a comparison of the two yeasts. During anaphase in S. pombe p17(nhp2) trails segregating chromatin, while in S. cerevisiae the protein segregates alongside bulk chromatin. The pattern of segregation comparing haploid and diploid S. cerevisiae cells suggests that p17(nhp2) is closely associated with the rDNA during nuclear division.

Amino Acid Sequence↗
PubMed1999

The cytochrome b5 tail anchors and stabilizes subdomains of human DNA topoisomerase II alpha in the cytoplasm of retrovirally infected mammalian cells.

DNA topoisomerase II (topo II) is the target of many anticancer drugs and is often altered in drug-resistant cell lines. In some tumor cell lines truncated isoforms of topo IIalpha are localized to the cytoplasm. To study the localization and function of individual enzyme domains, we have epitope-tagged several fragments of human topo IIalpha and expressed them by retroviral infection of rodent and human cells. We find that fusion of the topo II fragments to the hydrophobic tail of human liver cytochrome b5 anchors the fusion protein to the outer face of cytoplasmic membranes, as determined by colocalization with calnexin and selective detergent permeabilization. Moreover, whereas the minimal ATPase domain (aa 1-266) is weakly and diffusely expressed, addition of the cytb5 anchor (1-266-b5) increases its steady-state level 16-fold with no apparent toxicity. Similar results are obtained with the complete ATPase domain (aa 1-426). A C-terminal domain (aa 1030-1504) of human topo IIalpha containing an intact dimerization motif is stably expressed and accumulates in the nucleus. Fusion to the cytb5 anchor counteracts the nuclear localization signal and relocalizes the protein to cytoplasmic membranes. In conclusion, we describe a technique that stabilizes and targets retrovirally expressed proteins such that they are exposed on the cytoplasmic surface of cellular membranes. This approach may be of general use for regulating the nuclear accumulation of drugs or proteins in living cells.

Animals↗
PubMed1999

Crystal structure of the human protein kinase CK2 regulatory subunit reveals its zinc finger-mediated dimerization.

Protein kinase CK2 is a tetramer composed of two alpha catalytic subunits and two beta regulatory subunits. The structure of a C-terminal truncated form of the human beta subunit has been determined by X-ray crystallography to 1.7 A resolution. One dimer is observed in the asymmetric unit of the crystal. The most striking feature of the structure is the presence of a zinc finger mediating the dimerization. The monomer structure consists of two domains, one entirely alpha-helical and one including the zinc finger. The dimer has a crescent shape holding a highly acidic region at both ends. We propose that this acidic region is involved in the interactions with the polyamines and/or catalytic subunits. Interestingly, conserved amino acid residues among beta subunit sequences are clustered along one linear ridge that wraps around the entire dimer. This feature suggests that protein partners may interact with the dimer through a stretch of residues in an extended conformation.

Amino Acid Sequence↗
PubMed1999

Nitric oxide synthase in the guinea pig preoptic area and hypothalamus: distribution, effect of estrogen, and colocalization with progesterone receptor.

Nitric oxide (NO) may function as an intercellular messenger in the hypothalamus and may play a role in the control of gonadotropin-releasing hormone (GnRH) secretion and sexual behavior. Progesterone also plays an important role in the regulation of reproductive functions. Recent experiments have shown that progesterone-induced sexual behavior in ovariectomized, estrogen-primed rats was caused by the release of NO from nitric oxide synthase (NOS)-containing neurons and the subsequent stimulation of the release of GnRH. To provide further neuroanatomical support for the role of NO in these gonadal steroid-dependent behavioral and physiological processes, we determined (1) the distribution of the nicotinamide-adenosine-dinucleotide phosphate-diaphorase (NADPHd) and NOS enzymes in the guinea pig preoptic area and hypothalamus, regions that contain steroid receptors; (2) the effect of estrogen on NADPHd activity in these regions; and (3) the neuroanatomical relationship between NOS and the progesterone receptor (PR). For this purpose, single-(NADPHd) and double- (NADPHd with NOS or NADPHd with PR or NOS with PR) staining techniques were applied to sections of brains of guinea pigs. The studies showed scattered NADPHd-positive neurons in most parts of the preoptic area and heavily stained cells in the hypothalamus. In these regions, the pattern and density of NOS immunoreactivity closely corresponded to the pattern of NADPHd staining. Quantitative analysis showed an increase in the number of NADPHd-positive neurons in the ventrolateral nucleus of ovariectomized animals primed with estradiol. Approximately 16% of the NOS-immunoreactive (IR) cells in the rostral preoptic area and 55% of NOS-IR cells in the ventrolateral nucleus displayed PR immunoreactivity. These results suggest that NOS may be regulated by gonadal steroids and provide neuroanatomical evidence that progesterone may exert its effect directly on more than half of NOS-synthesizing cells in the ventrolateral nucleus, a key region in the control of sexual behavior.

Animals↗