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Biomedical subjects

V Dubois

Publications and source records attributed to V Dubois.

At least 37 records · Page 2Linked to original sources
PubMed2001

Knee reconstruction with prosthesis and muscle flap after total arthrectomy.

A massive prosthesis and medial gastrocnemius muscle transfer were used to reconstruct the knee after extracapsular en bloc excision for bone sarcoma. Magnetic resonance images showed intraarticular involvement. This technique was used in nine patients, six men and three women aged 18 to 51 years, with primary malignant bone tumors of the knee. Extraarticular resection of the knee, including the patella, was done in every case. A knee prosthesis was implanted, and the extensor mechanism was reconstructed by transfer of the medial gastrocnemius muscle and pes anserinus tendons. All resections had negative margins. There were no local recurrences, but metastases occurred in two patients. Infection was the only major complication and was seen in two patients. The mean postoperative Musculoskeletal Tumor Society score was 61% (range, 36%-100%). The mean postoperative range of flexion was 62 degrees (range, 30 degrees-90 degrees), and the mean extensor lag was 12 degrees (range, 0 degrees-40 degrees). Three patients required a crutch to walk. The functional outcome was poor in the two patients whose proximal tibia was removed with the joint, suggesting that arthrodesis may be best in this situation. In properly selected patients, prosthesis and muscle flap reconstruction provides acceptable function and a good cosmetic result.

Adolescent↗
PubMed2001

Nosocomial outbreak due to a multiresistant strain of Pseudomonas aeruginosa P12: efficacy of cefepime-amikacin therapy and analysis of beta-lactam resistance.

Over a 3-year period, 67 patients of the Hospital of Pau (Pau, France), including 64 patients hospitalized in the adult intensive care unit (ICU), were colonized and/or infected by strains of Pseudomonas aeruginosa P12, resistant to all potentially active antibiotics except colistin. Most patients were mechanically ventilated and presented respiratory tract infections. Since cefepime and amikacin were the least inactive antibiotics by MIC determination, all ICU patients were treated with this combination, and most of them benefited. Cefepime-amikacin was found highly synergistic in vitro. Ribotyping and arbitrary primer-PCR analysis confirmed the presence of a single clonal isolate. Isoelectrofocusing revealed that the epidemic strain produced large amounts of the chromosomal cephalosporinase and an additional enzyme with a pI of 5.7, corresponding to PSE-1, as demonstrated by PCR and sequencing. Outer membrane protein profiles on sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the absence of a ca. 46-kDa protein, likely to be OprD, and increased production of two ca. 49- and 50-kDa proteins, consistent with the outer membrane components of the efflux systems, MexAB-OprM and MexEF-OprN. Thus, we report here a nosocomial outbreak due to multiresistant P. aeruginosa P12 exhibiting at least four mechanisms of beta-lactam resistance, i.e., production of the penicillinase PSE-1, overproduction of the chromosomal cephalosporinase, loss of OprD, and overexpression of efflux systems, associated with a better activity of cefepime than ceftazidime.

Adult↗
PubMed2000

JC virus genotypes in France: molecular epidemiology and potential significance for progressive multifocal leukoencephalopathy.

JC virus (JCV) induces progressive multifocal leukoencephalopathy (PML), especially in human immunodeficiency virus (HIV)-infected patients. Although JCV genotypes have primarily been associated with geographic patterns, a distinctive neuropathogenicity was recently attributed to genotype 2. A multicenter study was conducted to describe the distribution of JCV genotypes in France and to investigate correlations between genotypes and PML. Genotypes were determined by sequencing 494 bp in the VP1 capsid gene. Peripheral JCV was studied in 65 urine samples from 43 HIV-infected patients and from 22 control subjects. Genotypes 1, 4, 2, and 3 were detected in 52.3%, 30.8%, 12.3%, and 4.6% of the samples, respectively. In 56 brain or cerebrospinal fluid samples, PML-associated JCV of genotypes 1, 2, 4, and 3 was found in 66%, 19.7%, 8.9%, and 5.4%, respectively. Infection with JCV genotypes 1 or 2 was correlated with PML (odds ratio, 3.29). On the other hand, infection with JCV genotype 4 could represent a lower risk for PML.

AIDS-Related Opportunistic Infections↗
PubMed2000

PCR detection of human enteric viruses in bathing areas, waste waters and human stools in Southwestern France.

Detection of human pathogenic viruses by molecular techniques might be suitable for identifying viral pollution in environmental waters and for improving diagnosis in patients. Environmental samples were taken from bathing areas and sewage treatment plants in southwestern France. Small volume samples (50 microL) were tested. Five groups of enteric pathogenic viruses were studied: enteroviruses, Norwalk-like viruses (NLVs), hepatitis A virus, rotaviruses and adenoviruses. Moreover, human samples were tested for NLV. After extraction of viral nucleic acids (Boom's procedure), a nested polymerase chain reaction was conducted before hybridization. Five bathing waters out of 26 were positive for one viral group, without systematic association with bacterial contamination. Eight sewage plant samples out of 13 were positive for at least one viral group. Seven patients out of 45 were NLV-positive. Molecular techniques allow efficient screening of viral contamination in environmental waters and the study of NLV molecular epidemiology.

Adenoviridae↗
PubMed1999

Sulfur mustard upregulates the expression of interleukin-8 in cultured human keratinocytes.

Although the morphological description of sulfur mustard (SM) injury is well characterised, little is known of the molecular mediators involved in cutaneous toxicity. Since infiltration by lymphocytes and PMNs represents one of the very first events observed in vivo upon exposure to SM, this study examined whether SM exposure can modify the expression by cultured human keratinocytes of interleukin-8, one of the most important chemoattractants for polymorphonuclear leukocytes (PMNs) in humans. Conditioned medium harvested from control keratinocyte cultures showed a gradual accumulation of this cytokine over time followed by a levelling off after 12 hours. Upon treatment with 10(-6) and 10(-5) M SM, no significant difference compared to the control situation was observed. After 6 h, a significantly higher amount of IL-8 was secreted by human keratinocytes treated with 10(-4) M SM and the accumulation of the cytokine persisted up to 24 h after exposure. The expression of IL-8 mRNA was assessed semi-quantitatively (RT-PCR) at the same time points in control and SM-treated (10(-4) M) human keratinocytes. When compared to control cultures, a clear upregulation of IL-8 mRNA levels was observed 6 and 12 h after SM exposure, which is consistent with the secretion pattern of the protein. The present observation indicates that increased secretion of IL-8 by human keratinocytes represents an early event of the inflammatory reaction following SM which is coherent with the reported delay in the recruitment of lymphocytes and PMNs observed in vivo.

Animals↗
PubMed1999

Human polyomavirus JC latency and reactivation status in blood of HIV-1-positive immunocompromised patients with and without progressive multifocal leukoencephalopathy.

BACKGROUND: Human polyomavirus JC (JCV) induces human progressive multifocal leukoencephalopathy (PML) in patients with AIDS. Peripheral blood mononuclear cells (PBMC) of HIV-1-positive immunocompetent and immunocompromised patients can harbour JCV genome, but their precise role in JCV latency or reactivation status before the onset of PML remains hypothetical. OBJECTIVES: To assess JCV latency or reactivation status in PBMC of HIV-1-positive immunocompromised patients without PML. DESIGN: A group of 82 HIV-1-positive immunocompromised patients who did not have PML were compared with 10 patients with AIDS and PML and with 69 HIV-1-positive immunocompetent patients without PML. METHODS: DNA and total RNA were extracted from PBMC. The presence of JCV DNA was demonstrated by a semi-nested polymerase chain reaction (PCR). By using primer pairs specific for an early gene,T, and a late gene, VP1, the expression of both early and late gene mRNA in PBMC could be identified using reverse transcriptase (RT) PCR. RESULTS: JCV DNA was detected by PCR in 17.4% of 69 HIV-1-positive immunocompetent patients, in 23.2% of 82 HIV-1-positive immunocompromised patients, and in 60% of 10 patients with AIDS and PML. No correlation could be drawn between the detection of JCV DNA in the PBMC and the clinical or biological status of the HIV-1-positive patients. By using RT-PCR procedures, no expression of JCV early and late mRNA in PBMC was found in any patients. CONCLUSIONS: JCV DNA is detectable in the PBMC of 20.5% of 151 HIV-1-infected patients independently of the CDC (Centers for Disease Control and Prevention) stages of the infection. Moreover, our results suggest that active replication of JCV in PBMC appears to be absent or at least a very rare event in HIV-1-positive immunocompromised patients with and without PML.

Acquired Immunodeficiency Syndrome↗
PubMed1999

A hospital outbreak of gastroenteritis possibly related to the contamination of tap water by a small round structured virus.

Small round structured viruses (SRSVs) are a major cause of gastroenteritis in institutions and sensitive new molecular techniques allow rapid diagnosis and the establishment of control measures. In January 1999, a 10 day-long outbreak of gastroenteritis in a re-education ward, was reported by a hospital hygiene department. A potential common source of contamination was tap water. The stools of six patients with gastroenteritis and seven tap water samples from the hospital ward, were tested for SRSV by reverse transcription and polymerase chain reaction (RT-PCR): three stools and four water samples, all bacteriologically negative, were SRSV-positive. Nucleotide sequencing of a fragment of the SRSV polymerase gene showed that the sequences of the positive samples (two patients and four water samples) were identical (genogroup II). We cannot exclude interhuman transmission of SRSV together with viral soiling of some taps in the ward, but this hospital infection was more likely due to the transient contamination of the ward supply of drinking water with a SRSV strain.

Caliciviridae Infections↗
PubMed1998

JC virus remains latent in peripheral blood B lymphocytes but replicates actively in urine from AIDS patients.

JC virus (JCV) is thought to reach the central nervous system by a vascular route. To determine whether JCV is conveyed in peripheral blood as latent or reactivated virus, blood leukocytes, plasma, and urine from 50 AIDS patients and plasma and B lymphocytes from 60 AIDS patients were investigated. Peripheral blood from 88 human immunodeficiency virus-negative blood donors was studied. Nested polymerase chain reaction assays allowed the identification of JCV T DNA and VP1 mRNAs. The latter indicate viral replication. Blood harbored JCV DNA in 31.8% of AIDS patients (only 2.3% of blood donors; P > .001) and urine in 56%. VP1 mRNAs were detected in blood of 1 AIDS patient. Notably, 38% of DNA-positive urine samples and 10 cerebrospinal fluid samples (CSF) from AIDS patients with progressive multifocal leukoencephalopathy contained JCV mRNAs. Thus, JCV was significantly more frequent in blood from AIDS patients than from controls, but, in most instances, it was latent, whereas active replication was detected in urine and CSF.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Prevalence of JC virus viraemia in HIV-infected patients with or without neurological disorders: a prospective study.

Progressive Multifocal Leukoencephalopathy (PML) is a severe demyelinating disease, which is rapidly fatal and is due to JC virus (JCV) infection, which especially occurs in HIV-infected patients. To investigate JCV pathophysiology and to evaluate the predictive value of JCV detection in blood, we looked for JCV DNA in leukocytes and plasma of 96 patients without any neurological symptoms and 109 patients with neurological diseases, among whom 19 were suffering from PML. JCV genome was detected in about 18% of all patients, i.e. 15.6% of patients with central nervous system disorders except PML, 13.5% of patients without neurological symptoms and significantly more often in PML patients (47.6%). Both leukocytes and plasma were tested; in plasma, JCV DNA was found in 36.1% of positive patients and in cells in 80.5%. Surprisingly in seven instances only the plasma contained JCV genome. One-year follow-up of these patients showed that the absence of JCV DNA in blood was associated with a very low probability of developing PML (negative predictive value=0.99).

Blotting, Southern↗
PubMed1997

Western immunoblotting and enzymatic activity analysis of cathepsin D in human breast cancer cell lines of different invasive potential. Regulation by 17beta-estradiol, tamoxifen and ICI 182,780.

We used enzymatic activity and immunochemical quantifications to analyse the expression and secretion of cathepsin D by human breast cancer cell lines of different invasive potentials (MCF-7/6, MCF-7/AZ, MDA-MB-231). This study does not directly prove that cathepsin D or procathepsin D is involved in human breast cancer cell invasion and metastasis but it shows that the proportion of procathepsin D (activity and antigen) secreted by the human breast cancer cell lines tested correlates with their invasive potential. In the estrogen receptor-positive MCF-7 subclones, this proportion is increased by estradiol only in the invasive MCF-7/6 variant. The cell content in procathepsin D is increased by estrogens to a greater extent in MCF-7/6 cells as compared to non-invasive MCF-7/AZ cells. Tamoxifen appears to be an estrogen agonist concerning cathepsin D regulation, whereas ICI 182,780 is a true antagonist. Our results suggest that synthesis and secretion of cathepsin D are regulated at two distinct levels and differentially affected by estrogens. Synthesis only seems to be affected in non-invasive MCF-7/AZ cells, whereas in invasive MCF-7/6 cells, both synthesis and the efficiency of secretion are increased by estrogens. Our results also confirm that the key site of regulation leading to lysosomal enzyme oversecretion is the Golgi apparatus insulin-like growth factor-II/mannose 6-phosphate receptor.

Acids↗
PubMed1997

Latency and reactivation of JC virus in peripheral blood of human immunodeficiency virus type 1-infected patients.

JC virus (JCV) acts as an opportunistic virus in immunocompromised human immunodeficiency virus type 1 (HIV-1)-infected patients. The role of peripheral blood cells in central nervous system invasion, before the onset of progressive multifocal leukoencephalopathy (PML), remains controversial. In order to clarify JCV latency or reactivation status in peripheral blood, 72 HIV-1-infected patients were studied, together with 7 HIV-1-positive PML patients and 50 blood donors. Blood leukocytes, plasma, and B lymphocytes were investigated by two complementary DNA amplification procedures within the early T and late VP1 JCV genes and two reverse transcription techniques for the detection of corresponding early transcripts and mRNAs. JCV DNA was detected in 40.3% of the HIV-1-infected patients but only 8% of the blood donors (P < 0.001). Leukocytes represented 82.7% of the positive samples, but plasma from 12 patients (41.4%) contained JCV DNA. B lymphocytes seemed to be involved in the natural history of JCV but did not represent the unique cell target. JCV DNA was intermittently found in blood, and JCV mRNAs for VP1 capsid protein were detected exclusively in one PML patient. Such observations demonstrate that JCV, when detected in blood, does not undergo active multiplication. They support the JCV hematogenous spread hypothesis, but do not indicate any direct link between peripheral virus and dissemination in the central nervous system at the time of immunodepression.

AIDS-Related Opportunistic Infections↗
PubMed1997

Mutations in BRCA1 and BRCA2 in breast cancer families: are there more breast cancer-susceptibility genes?

To estimate the proportion of breast cancer families due to BRCA1 or BRCA2, we performed mutation screening of the entire coding regions of both genes supplemented with linkage analysis of 31 families, 8 containing male breast cancers and 23 site-specific female breast cancer. A combination of protein-truncation test and SSCP or heteroduplex analyses was used for mutation screening complemented, where possible, by the analysis of expression level of BRCA1 and BRCA2 alleles. Six of the eight families with male breast cancer revealed frameshift mutations, two in BRCA1 and four in BRCA2. Although most families with female site-specific breast cancers were thought to be due to mutations in either BRCA1 or BRCA2, we identified only eight mutations in our series of 23 site-specific female breast cancer families (34%), four in BRCA1 and four in BRCA2. According to the posterior probabilities calculated for mutation-negative families, based on linkage data and mutation screening results, we would expect 8-10 site-specific female breast cancer families of our series to be due to neither BRCA1 nor BRCA2. Thus, our results suggest the existence of at least one more major breast cancer-susceptibility gene.

BRCA1 Protein↗
PubMed1996

Emergencies and somatization.

The article presents the clinical profile of 72 patients with somatization seen by a psychiatric team at the request of somaticians in a emergency service in St Luc hospital (Brussels-Belgium). These include 37.5% of mood disorders, 11% of psychotic disorders and 20% of serious anxiety disorders. The psychiatric antecedents of these patients are very poor. Only the combined intervention of the somatician and the psychiatrist can improve the compliance and the level of psychiatric care which is very low.

Adult↗
PubMed1996

Detection of JC virus DNA in the peripheral blood leukocytes of HIV-infected patients.

OBJECTIVES: To assess whether JC virus (JCV) DNA is frequently harboured by peripheral blood leukocytes (PBL) in HIV-positive patients, before the onset of progressive multifocal leukoencephalopathy (PML). DESIGN: The polyomavirus JCV induces PML in immunocompromised persons and particularly AIDS patients. Leukocytes may play a central part in the onset of PML, but their precise role in JCV latency and reactivation still remains hypothetical. The controversial presence of JCV DNA in PBL has been, until now, investigated only among small groups of patients. We therefore studied 157 HIV-positive persons and compared them with 65 HIV-negative immunocompromised patients. METHODS: DNA was extracted from PBL. The presence of JCV DNA was demonstrated by the polymerase chain reaction (PCR) alone or combined with a molecular hybridization assay. RESULTS. The presence of JCV DNA was ascertained by PCR and hybridization in 28.9% of 135 HIV-infected persons at all stages of HIV infection and only 16.4% of 61 HIV-negative immunocompromised patients. No correlation could be drawn between the detection of JCV DNA and the clinical or biological status of the HIV-positive patients. CONCLUSIONS: JCV DNA is detectable in the PBL of 28.9% of HIV-infected persons, even in the early stages of infection. JCV is more seldomly amplified in HIV-negative immunocompromised patients. Further work is in progress to determine the prognostic value of the presence of JCV DNA in the blood of HIV-positive patients.

Adult↗
PubMed1995

Intracellular levels and secretion of insulin-like-growth-factor-binding proteins in MCF-7/6, MCF-7/AZ and MDA-MB-231 breast cancer cells. Differential modulation by estrogens in serum-free medium.

The synthesis and secretion of insulin-like growth factor binding proteins (IGFBPs) were studied in MDA-MB-231 (estrogen-receptor-negative), MCF-7/6 (estrogen-receptor-positive, invasive) and in MCF-7/AZ (estrogen-receptor-positive, non-invasive) human breast carcinoma cell lines. Cells were grown or maintained in a chemically defined medium. Under these conditions, we found different patterns of IGFBPs in the three cell types. MDA-MB-231 cells secrete most of the IGFBPs they produce whereas MCF-7/6 and MCF-7/AZ cells maintain a high intracellular level. In MDA-MB-231 cells, the major IGFBP is IGFBP-4 which is the minor form in MCF-7/6 and MCF-7/AZ cells. IGFBP-2 and IGFBP-5 are predominant in MCF-7/6 cells while MCF-7/AZ cells produce far less IGFBPs and do not contain detectable amounts of 29-32-kDa forms (IGFBP-5). In MCF-7/6 cells, estradiol-17 beta specifically decreases both the intracellular content and secretion of IGFBP-2 and IGFBP-5. Estrogen regulation of IGFBPs cell content and secretion was found to be tamoxifen-resistant, and only slightly antagonized by ICI 182,780, a pure antiestrogen. The function of these regulations relative to the invasive phenotype and proliferation has now to be determined.

Breast Neoplasms↗
PubMed1993

Estrogen and insulin modulation of intracellular insulin-like growth factor binding proteins in human breast cancer cells: possible involvement in lysosomal hydrolases oversecretion.

Differences in insulin-like growth factor binding proteins (IGFBPs) expressed within estrogen receptor positive (ER+, MCF-7/6) and negative (ER-, MDA-MB-231) human breast cancer cells cultured in chemically defined medium were observed. In the absence of insulin, 17 beta-estradiol affects this expression in ER+ cells by significantly reducing 34 and 28 kDa species. In ER+ cells, insulin appears to minimize the estrogen induced reduction of these 34 and 28 kDa IGFBPs and stimulates a 24 kDa type. We suggest that through its association with a given IGFBP, insulin-like growth factor-II (IGF-II) directs lysosomal enzymes to secretion by its binding to the mannose-6-phosphate/IGF-II receptors present in the Golgi apparatus. Alternatively, the association of IGF-II with another IGFBP would inhibit this binding and lead to its autocrine or intracrine mitogenic action via the IGF-I receptor.

Breast Neoplasms↗
PubMed1992

Why do patients consult the general practitioner? Determinants of their decision.

In order to obtain more information about the reasons why patients consult their general practitioner 1000 patients completed a questionnaire in the waiting rooms of eight general practices. After the consultation the patients received a second questionnaire. The aim of the study was to determine why people decide to consult their general practitioner about one complaint but not about a second complaint. Both questionnaires were based on the health belief model, augmented by three other factors: the perceptions patients have of their own abilities to cope with their condition (efficacy of self care), their knowledge about the complaint and their need for information. The results showed that two of the additional factors (efficacy of self care and need for information) as well as most of the factors of the health belief model (efficacy of general practitioner care, perceived severity of complaint and cues to consult) were important determinants of consulting the general practitioner. The results suggest that patients sometimes expect information from their general practitioner rather than medical treatment. Furthermore, as the perceived efficacy of general practitioner care is also an important determinant, unnecessary consultation or unnecessary delay in treatment could be prevented by offering patients information about the potential effectiveness of medical care or self care for specific conditions. Implications for general practitioners' daily practice and future research are discussed.

Attitude to Health↗