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Biomedical subjects

B Gauthier

Publications and source records attributed to B Gauthier.

At least 19 recordsLinked to original sources
PubMed2001

Laser assisted skin closure (LASC) by using a 815-nm diode-laser system accelerates and improves wound healing.

BACKGROUND AND OBJECTIVE: This study aimed to evaluate a 815-nm diode-laser system to assist wound closure to accelerate and improve healing process. STUDY DESIGN/MATERIALS AND METHODS: A total of 25 male hairless rats (mutant OFA Sprague-Dawley rats, IFFA-CREDO, L'Arbresle, France) with four dorsal skin incisions were used for the study. For each wound, the good apposition of the edges was obtained with buried absorbable suture. In the laser group, the laser beam was applied spot by spot through a transparent adhesive dressing along two incisions with the following parameters: 1.5 W; 3 seconds; spot diameter, 2 mm; fluence, 145 J/cm(2). Both control wounds were closed with conventional suture techniques. The duration of the closure procedure was noted for each group. Clinical examination, histologic study, and measurement of tensile strength were performed at 3, 7, 15, and 21 days after surgery. Determination of activation of heat shock protein 70 (Hsp70) through immunocytochemistry was performed at days 1 and 7. RESULTS: LASC was 4 times faster to process than conventional suture: 1 minute 49 +/- 20.6 seconds vs. 7 minutes 26 +/- 62.2 seconds. In the laser group, healing was accelerated resulting in a more indiscernible scar than in the control groups. Histologic aspect was better with earlier continuous epidermis and dermis and a thinner resulting scar. Tensile strength was 30 to 58% greater than in control groups at 7 and 15 days (P < 0.001). Expression of Hsp70 was markedly induced in skin structures examined after laser exposure. CONCLUSIONS: This study shows the ability of the 815-nm diode-laser system to assist wound closure leading to an acceleration and an improvement of wound healing with indiscernible resulting scar. The mechanisms of this phenomenon are still unclear but further investigations are in progress to attempt to explain them.

Animals↗
PubMed2000

The paired homeodomain transcription factor Pax-2 is expressed in the endocrine pancreas and transactivates the glucagon gene promoter.

Glucagon gene expression is controlled by at least four DNA elements within the promoter; G2, G3, and G4 confer islet-specific expression, while G1 restricts glucagon transcription to alpha cells. Two islet-specific complexes are formed on G3, the insulin-responsive element of the glucagon gene; one of these corresponds to the paired homeodomain protein Pax-6, a major glucagon gene transactivator that plays a crucial role in alpha cell development. We describe here the identification of the second complex as Pax-2, another member of the paired box family. Pax-2 is known to be crucial for the development of the urogenital tract and of the central nervous system, but its presence in the endocrine pancreas has not been reported. We detected Pax-2 gene expression by RT-PCR; in islets, Pax-2 is present as two alternative splicing isoforms, Pax-2A and Pax-2B, whereas in the glucagon- and insulin-producing cell lines alphaTC1 and Min6, a distinct isoform, Pax-2D2, is found in addition to Pax-2B. Both islet-specific isoforms bind to the enhancer element G3 and to the alpha-specific promoter element G1 that also interacts with Pax-6. Pax-2A and Pax-2B dose-dependently activate transcription from the G3 and the G1 elements both in heterologous and in glucagon-producing cells. Our data indicate that Pax-2 is the third paired domain protein present in the endocrine pancreas and that one of its roles may be the regulation of glucagon gene expression.

Animals↗
PubMed1999

Vitamin E treatment of focal segmental glomerulosclerosis: results of an open-label study.

Experimental data indicate that excessive production of reactive oxygen molecules contributes to progressive renal injury and that treatment with antioxidants attenuates this damage. Therefore, we investigated whether vitamin E supplementation could ameliorate renal disease and reduce proteinuria in children with a variety of kidney disorders. Vitamin E, 200 IU twice daily, was administered orally to 11 children with focal segmental glomerulosclerosis (FSGS) (group A) and 9 patients with miscellaneous kidney diseases (group B) [Henoch-Schönlein purpura nephritis (n=3), urinary tract anomalies (n=2), non-specific immune complex glomerulonephritis (n=2), IgA nephropathy (n=1), and reflux nephropathy (n=1)]. The duration of vitamin E treatment, when no other therapy was introduced, was 2.9+/-0.4 months. Proteinuria was determined by measuring the protein:creatinine ratio (mg/mg) in an early morning urine specimen. In children with FSGS, administration of vitamin E lowered the protein:creatinine ratio in 10 of 11 patients from 9. 7+/-5.1 to 4.1+/-1.1 (P<0.005). In contrast, among children with miscellaneous renal diseases, vitamin E had no beneficial impact on urinary protein excretion-protein:creatinine ratio 2.5+/-1.0 pre versus 2.4+/-1.2 post antioxidant. Vitamin E supplementation had no effect on glomerular filtration rate, serum albumin, or cholesterol concentration in either group of patients. These findings suggest that reactive oxygen molecules may play a more-prominent role in causing renal injury in patients with FSGS than in other kidney disorders. Antioxidant therapy may be a useful adjunct in the treatment of children with FSGS and proteinuria that is refractory to standard medical management.

Adolescent↗
PubMed1999

Cholesteryl ester transfer protein gene expression during differentiation of human preadipocytes to adipocytes in primary culture.

The expression pattern of the CETP gene in relationship to that of LPL, adipsin, PPARgamma, C/EBPalpha, ADD1/SREBPI and actin was examined by RT-PCR during differentiation of human fibroblastic preadipocytes to adipocytes in primary culture. Preadipocytes were isolated from subcutaneous fat obtained from healthy female subjects undergoing mammary reduction procedures, and induced to differentiate in culture. Morphologically, adipogenesis was confirmed by the accumulation of lipid droplets in cells. We show that the gene encoding CETP is expressed in preadipocytes and is present throughout differentiation as compared to LPL and adipsin which were detected in the majority of samples by day 2 or 3 of adipogenesis. The transcription factors, PPARgamma, ADD1/SREBP1 and C/EBPalpha were expressed by day 2, concomitant with the appearance of LPL and adipsin but subsequent to the appearance of CETP. CETP mRNA was not detectable in human skin fibroblasts. These studies demonstrate that CETP. expression is induced at an early stage of commitment to the adipocyte lineage and may be activated by transcription factor(s), which are not members of the PPAR, ADD1/SREBP1 or C/EBP families.

Actins↗
PubMed1999

The treatment of negative symptoms: a clinical and methodological study.

The primary objective of this study was to evaluate the efficacy, safety and tolerability of remoxipride (controlled release) versus haloperidol in patients with negative symptoms. The study comprised a multicentre, randomised, double-blind, parallel-group clinical trial. Two hundred and five patients were randomised to either remoxipride or haloperidol. Patients eligible for this study were aged 18-65 years, met the DSM-III-R diagnosis for chronic schizophrenia and the Positive and Negative Symptoms Scale (PANSS) criteria for predominant negative symptoms. There was a statistically significant reduction in the PANSS scores of at least 20% from baseline to last rating for 39 remoxipride (49.4%) and 45 haloperidol (47.6%) treated patients. There were no statistical differences found between the two treatment groups with respect to improvement of negative symptoms and adverse events. The PANSS data suggest that both remoxipride and haloperidol improve the cluster of negative symptoms concerned with social functioning. In addition, the design of the study provides a methodology that is appropriate to the study of primary negative symptoms in schizophrenia.

Adult↗
PubMed1999

Characterization of a cholesterol response element (CRE) in the promoter of the cholesteryl ester transfer protein gene: functional role of the transcription factors SREBP-1a, -2, and YY1.

Cholesteryl ester transfer protein (CETP) is expressed in human adipocytes, where it acts to promote selective uptake of HDL-CE (Benoist, F., M. McDonnell, P. Lau, R. Milne, and R. McPherson. 1997. J. Biol. Chem. 272: 23572;-23577). In contrast to other major sterol-responsive genes such as 3-hydroxy-3-methylglutaryl coenzyme A reductase CETP expression is up-regulated rather than down-regulated in response to cholesterol. To define elements involved in cholesterol-mediated up-regulation of CETP gene expression, deletion derivatives of the CETP promoter were cloned into a luciferase reporter construct and transfected into the human liposarcoma cell line SW872, cultured in the presence or absence of lipoproteins. A fragment associated with a positive cholesterol response was identified between nucleotides -361 and -138 (relative to the initiation site of transcription) of the promoter. This region contains a tandem repeat of a sequence known to mediate sterol dependent regulation of the hamster HMG-CoA reductase gene. We have putatively denoted this region, the cholesterol response element (CRE). Using gel mobility shift assays we demonstrate that both YY1 and SREBP-1 interact with the CRE of CETP. Furthermore, in transient co-transfection experiments, both YY1 and SREBP-1a were found to trans-activate, in a dose-dependent manner, the luciferase activity of constructs harboring the CRE. We also demonstrate that SREBP-2, is able to trans-activate a luciferase construct harboring the CRE although much less effectively as compared to SREBP-1. Finally, functional analysis of the CRE confirms its regulatory role in modulating CETP gene expression through its interaction with YY1 and SREBP-1a.

Animals↗
PubMed1998

Magnetic resonance imaging in acute pyelonephritis.

The diagnosis of acute pyelonephritis in children remains a clinical challenge. We assessed the feasibility of magnetic resonance imaging (MRI) detection of pyelonephritis in four pediatric patients and compared the results with renal cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney that coincided with photon-deficient regions in the radionuclide scans in two children with acute pyelonephritis. These findings confirm work in experimental animals and indicate that MRI can accurately detect acute pyelonephritis in children.

Acute Disease↗
PubMed1998

The high prevalence of obesity in Michigan primary care practices. An UPRNet study. Upper Peninsula Research Network.

BACKGROUND: Obesity is a risk factor for several chronic diseases and some cancers. We suspected that patients in our primary care practices were, on the average, heavier than state and national norms. METHODS: Rates of overweight patients in primary care practices were compared with rates from the Michigan Behavioral Risk Factor Survey (MBRFS) of 1993 and the National Health and Nutrition Evaluation Survey (NHANES) III Phase I (1988-91), the most recent state and national surveys for which summarized data were available. The 19 family practice offices of the rural Upper Peninsula Research Network (UPRNet) and two urban clinics in the Lansing area participated. We measured heights and weights of 5267 consecutive patients 18 years of age and older who visited one of the offices or clinics during the study period in 1996. RESULTS: Fifty-three percent of the primary care patients were overweight, and 28.5% were severely overweight. The age-adjusted rates were 51.0% and 27.5%, respectively. These rates are much higher than rates reported from the MBRFS (29.1% for overweight), and NHANES III Phase I (33% overweight, 14% severely overweight). The age-adjusted prevalence of overweight and severely overweight was higher in the rural than the urban sample: 52.5% vs 47.2% for overweight and 33.7% vs 25.6% for severely overweight, respectively. CONCLUSIONS: Compared with data from the Michigan Behavioral Risk Factor Survey of 1993 and the National Health and Nutrition Evaluation Survey III Phase I, a much larger proportion of patients visiting our primary care practices are overweight and severely overweight. The prevalence of obesity in primary care practices may be much higher than rates estimated from population-based surveys.

Adolescent↗
PubMed1997

Acute interstitial nephritis associated with IgA nephropathy in children.

IgA nephropathy (IgAN) is a relatively common glomerulopathy in children and adolescents. The etiology of this disease is uncertain. We previously reported a child with IgAN who developed acute interstitial nephritis. We now describe three pediatric patients, including the index case, who had IgAN and who developed concomitant acute interstitial nephritis in association with renal functional impairment. We suggest that this histopathological lesion be considered in any child with IgAN and unexpectedly severe kidney dysfunction.

Acute Disease↗
PubMed1997

Childhood/early adolescence-onset and adult-onset schizophrenia. Heterogeneity at the dopamine D3 receptor gene.

BACKGROUND: The dopamine D3 receptor gene (DRD3) is a meaningful candidate gene because it unifies the dopamine and the limbic hypotheses for schizophrenia. We tested for an allelic association between schizophrenia and the DRD3 Mscl alleles, hypothesising heterogeneity between childhood/early adolescence-onset schizophrenia (CO-SZ) and adult-onset schizophrenia (A-SZ). METHOD: The frequencies of the DRD3 alleles were compared between 70 DSM-III-R schizophrenics (35 CO-SZ and 35 A-SZ) and 79 controls. RESULTS: Compared with the controls, the subsample of A-SZ, but not CO-SZ, showed an over-proportion (P = 0.025) of allele 1. The association was not found in the total sample, combining the two subsamples. CONCLUSIONS: Consistently with former studies, our data suggest an aetiological heterogeneity between CO-SZ and A-SZ and a possible specificity of the excess of allele 1 to the familial form of schizophrenia and to schizophrenia with a better outcome.

Adolescent↗
PubMed1996

Increased urinary nitrite excretion in children with minimal change nephrotic syndrome.

OBJECTIVE: We tested the hypothesis that nitric oxide synthesis by the kidney is increased in children with primary nephrotic syndrome. METHODS: We examined the urinary excretion of nitrite, a stable metabolite of nitric oxide, using the Griess reaction, in children with nephrotic syndrome. RESULTS: In comparison with healthy children, patients with minimal change nephrotic syndrome had increased urinary nitrite excretion regardless of whether the disease was in relapse or remission (p < 0.025). In contrast, urinary nitrite excretion was similar in control subjects and patients with focal segmental glomerulosclerosis or IgA nephropathy. CONCLUSION: These findings indicate that measurement of urinary nitrite excretion may be a useful test to help discriminate between minimal change nephrotic syndrome and focal segmental glomerulosclerosis in children with idiopathic nephrotic syndrome.

Adolescent↗
PubMed1996

Long-term stability of diagnosis and symptom dimensions in a systematic sample of patients with onset of schizophrenia in childhood and early adolescence. I: nosology, sex and age of onset.

BACKGROUND: Little is known about the long-term outcome of schizophrenia that has its onset during childhood and early adolescence (early-onset schizophrenia, or EO-SZ). Whether or not EO-SZ is an aetiologically separate form of schizophrenia (SZ) is unresolved. METHOD: The study was a 14.8-year follow-up, using methods such as systematic sampling, evaluation of possible non-respondent bias, consensus best-estimate diagnoses (DSM-III-R) made independently in childhood and adulthood, measures of positive and negative dimensions, of non-psychotic behaviour disturbances (NPBD) and of developmental problems before the appearance of SZ. RESULTS: There was high stability of EO-SZ (n = 40) diagnoses (mean onset at 14.0 years) until adulthood (mean age at follow-up 28.8 years) but a lower stability of positive and negative schizophrenic dimensions. There was a poor outcome of EO-SZ, a strong over-representation of males but few gender differences, and no effect of age of onset on clinical features and outcome. CONCLUSIONS: EO-SZ taken as a whole shows no qualitative differences to adult-onset SZ. However, a distinction through the onset of preschizophrenic developmental problems or NPBD might be a way to investigate heterogeneity within EO-SZ.

Adolescent↗
PubMed1996

Long-term stability of diagnosis and symptom dimensions in a systematic sample of patients with onset of schizophrenia in childhood and early adolescence. II: Postnegative distinction and childhood predictors of adult outcome.

BACKGROUND: The aim of this study was to verify the presence and stability across life of the positive/negative distinction in early-onset schizophrenia (EO-SZ) through a longitudinal factor analysis of the schizophrenic dimensions, and to identify the factors predicting several indices of long-term outcome for EO-SZ. METHOD: Forty children consecutively referred for DSM-III-R schizophrenia (SZ) in a specific catchment area comprised the sample. RESULTS: Across a 14.8-year follow-up, longitudinal factor analysis identified two separate factors corresponding to the positive and negative symptom dimensions. We also observed that: the GAS rated over the last three years of adult illness and the severity of negative symptoms during the stabilised interepisode intervals in adulthood were the indices of adult outcome that were most easily predicted; and the best childhood predictors of adult outcome were premorbid functioning and severity of positive and negative symptoms during acute episodes. CONCLUSIONS: The presence of premorbid non-psychotic behaviour disturbances (NPBD) and premorbid developmental problems was not related to severity of outcome, in contrast to the former variables.

Adolescent↗
PubMed1996

Predicting daily maintenance dose of fluindione, an oral anticoagulant drug.

Due to large inter-individual variations, the dose of vitamin K antagonist required to target the desired hypocoagulability is hardly predictible for a given patient, and the time needed to reach therapeutic equilibrium may be excessively long. This work reports on a simple method for predicting the daily maintenance dose of fluindione after the third intake. In a first step, 37 patients were delivered 20 mg of fluindione once a day, at 6 p.m. for 3 consecutive days. On the morning of the 4th day an INR was performed. During the following days the dose was adjusted to target an INR between 2 and 3. There was a good correlation (r = 0.83, p < 0.001) between the INR performed on the morning of day 4 and the daily maintenance dose determined later by successive approximations. This allowed us to write a decisional algorithm to predict the effective maintenance dose of fluindione from the INR performed on day 4. The usefulness and the safety of this approach was tested in a second prospective study on 46 patients receiving fluindione according to the same initial scheme. The predicted dose was compared to the effective dose soon after having reached the equilibrium, then 30 and 90 days after. To within 5 mg (one quarter of a tablet), the predicted dose was the effective dose in 98%, 86% and 81% of the patients at the 3 times respectively. The mean time needed to reach the therapeutic equilibrium was reduced from 13 days in the first study to 6 days in the second study. No hemorrhagic complication occurred. Thus the strategy formerly developed to predict the daily maintenance dose of warfarin from the prothrombin time ratio or the thrombotest performed 3 days after starting the treatment may also be applied to fluindione and the INR measurement.

Administration, Oral↗