[Autochthonous viral hepatitis E in Languedoc-Roussillon].
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Adult↗
Biomedical subjects
F Dubois
Publications and source records attributed to F Dubois.
Imaging of pyelonephritis.
OBJECTIVE: Accurate diagnosis of pyelonephritis using clinical and laboratory parameters is often difficult, especially in children. The main aims of this prospective study were to compare the value of different imaging techniques [renal sonography, cortical scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc DMSA) and computed tomography (CT)] in detecting renal involvement in acute urinary tract infections and to determine the sensitivity of DMSA scans for permanent renal scars 6 months later. MATERIALS AND METHODS: Between February 1992 and January 1993, 55 children admitted to our pediatric unit with febrile symptomatic urinary tract infections were eligible for analysis. Ultrasonography (US), DMSA scanning and micturating cystourethrography were performed in every case. Only 18 children underwent CT. A second DMSA scan was performed in 48 children a mean of 7.5 months after the first. RESULTS: US abnormalities were found in 25 children (45 %). The first DMSA scan showed a parenchymal aspect suggestive of pyelonephritis in 51 patients (93 %). Among the 18 patients studied by CT, 14 had abnormalities. Normal US findings did not rule out renal parenchymal involvement. Scintigraphy appeared to be more sensitive than CT for renal involvement. The frequency and degree of initial renal parenchymal damage seemed to correlate with vesicoureteral reflux, but the most severe initial parenchymal defects were not associated with marked clinical or laboratory manifestations. Repeat DMSA scans, performed on 45 kidneys with abnormalities at the first examination, showed resolution in 19, improvement in 16, persistence in 8 and deterioration in 2. The prevalence of vesicoureteral reflux was not higher in patients with renal scarring on the second DMSA scan than in patients whose scans showed an improvement. CONCLUSION: DMSA scans should be considered as a reference in the detection and follow-up of renal scarring associated with acute urinary tract infection as this technique is more sensitive than US and CT, the latter being unsuitable because it entails radiation exposure and sedation of patients.
Acute Disease↗
Could serum HBV DNA level in the early phase of acute hepatitis B predict evolution to chronic HBV carriage?
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Acute Disease↗
Cationic lipids delay the transfer of plasmid DNA to lysosomes.
Plasmid 35S DNA, naked or associated with different cationic lipid preparations was injected to rats. Subcellular distribution of radioactivity in the liver one hour after injection, was established by centrifugation methods. Results show that at that time, 35S DNA has reached lysosomes. On the contrary, when 35S DNA was complexed with lipids, radioactivity remains located in organelles whose distribution after differential and isopycnic centrifugation, is clearly distinct from that of arylsulfatase, lysosome marker enzyme. Injection of Triton WR 1339, a specific density perturbant of lysosomes, four days before 35S DNA injection causes a density decrease of radioactivity bearing structures, apparent one hour after naked 35S DNA injection but visible only after more than five hours, when 35S DNA associated with a cationic lipid is injected. These observations show that cationic lipids delay the transfer to lysosomes, of plasmid DNA taken up by the liver.
Animals↗
[Detection of hepatitis B: better efficacy at the 8th month of gestation than at the 6th month].
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Adult↗
Soluble form of Lamp II in purified rat liver lysosomes.
Lamp II (for lysosomal associated membrane protein II) is an integral type I glycoprotein. It consists of a very large and heavily glycosylated luminal domain, a single transmembrane segment, and a short cytoplasmic tail. We show that in highly purified lysosomes from rat liver, Lamp II, immunodetected with a monoclonal antibody on Western blots, it surprisingly distributed between a membrane bound form and a "soluble" form. The partition of the protein between the membrane and the content of lysosomes is strongly pH dependent. The soluble Lamp II population is sensitive to pH dependent aggregation as it is for many lysosomal content enzymes.
Animals↗
Phagocytosis by rat liver: relationships between phagosomes and lysosomes.
To study the transfer of phagocytosed components from phagosomes to lysosomes, we have investigated phagocytosis by rat liver of killed Staphylococcus aureus labelled with (125)I tyramine cellobiose. Lysosomes were identified by injecting the animals with Triton WR1339, a non ionic detergent that is endocytosed by the liver and accumulates in lysosomes, causing a marked decrease of their density; that allows these organelles to be well separated from other particles in a density gradient. Bacteria were quickly taken up by the liver; their uptake is followed by a slow degradation as ascertained by the increase of acid-soluble radioactivity in the homogenates with time. Triton WR1339 injection does not affect the uptake and the degradation of the particles. Differential centrifugation of homogenates shows that at any time after injection, most of the radioactivity is recovered in the mitochondrial fractions. Distributions of acid precipitable and acid soluble radioactivities amongst subcellular structures present in mitochondrial fractions were studied by isopycnic centrifugation in sucrose gradients, at increasing times after bacteria injection. Results show that: 1) acid-precipitable radioactivity is quasi-exclusively present in gradient fractions of high density, well separated from the fractions where there are recovered lysosomes; 2) with time, acid-soluble radioactivity is more and more associated with lysosomes, however, a significant proportion can be detected for many hours after injection, in gradient fractions where acid-precipitable radioactivity is located. The most plausible explanation of our observations is that phagocytosed particles are degraded in phagosomes and that the degradation products are delivered to lysosomes, probably by a vesicular process.
Animals↗
Localization of tobacco cytosolic glutamine synthetase enzymes and the corresponding transcripts shows organ- and cell-specific patterns of protein synthesis and gene expression.
The subcellular localization of glutamine synthetase in tobacco and the differential expression of two genes encoding cytosolic enzyme was investigated using both immunocytochemistry and in situ hybridization. Two full length cDNA clones each encoding cytosolic GS (Gln 1-3 and Gln 1-5) were isolated from a tobacco seeding cDNA library. A strong homology was found in the coding region of the two clones whereas the 3'- and 5'-untranslated sequences were dissimilar. In order to determine the levels of transcription, specific sequences from Gln1-3 and Gln1-5 were used in an RNAse protection assay. This experiment clearly showed that the gene encoding Gln1-3 is expressed in roots and flowers whereas the gene encoding Gln1-5 is transcribed at a high level in stems and at a lower level in roots and flowers. Immunogold labelling was used to examine the subcellular and cellular distribution of glutamine synthetase in vegetative and reproductive organs of tobacco plants. In mature leaf tissue or petals and sepals, plastidic GS was visualised only in the stroma matrix of chloroplasts and plastids. Cytosolic GS was detected in a number of vegetative or reproductive organs including leaves and flowers. In leaves cytosolic GS was preferentially located in the vascular tissue. In situ hybridization was performed using sections of tobacco organs and specific antisense RNA probes to the genes encoding Gln1-3 and Gln1-5. Gln1-5 transcripts were localised in the vascular tissues of stems and roots whereas Gln1-3 transcripts were detected in all root cells and floral organs including petals, sepals and anthers.
Antisense Elements (Genetics)↗
Identification of a tobacco cDNA encoding a cytosolic NADP-isocitrate dehydrogenase.
A cDNA which encodes a specific member of the NADP-dependent isocitrate dehydrogenase (ICDH) multi-isoenzyme family has been isolated from a tobacco cell suspension library, and the expression pattern of ICDH transcripts examined in various plant tissues. To assign this cDNA to a specific ICDH isoenzyme, the major, cytosolic ICDH isoenzyme of tobacco leaves (ICDH1) was purified to homogeneity and its N-terminus as well as several tryptic peptides, representing 30% of the protein, were sequenced. The comparison of these amino acid sequences with the deduced protein sequence of the cDNA confirmed that this clone encodes for ICDH1. The total ICDH specific activity and protein content were higher in vascular-enriched tobacco leaf tissue than in deveined (depleted in midrib and first-order veins) leaves. Taking advantage of antibodies raised against either ICDH1 or the chloroplastic ICDH2 isoenzyme from tobacco cell suspensions, an immuno-cytochemical approach indicated that the ICDH1 isoenzyme, located in the cytosolic compartment of tobacco leaf cells, is responsible for this expression pattern. This observation was confirmed by northern blot analyses, using a specific probe obtained from the 3' non-coding region of the ICDH1 cDNA. A comparison of ICDH protein sequences shows a large degree of similarity between eukaryotes (> 60%) but a poor homology is observed when compared to Escherichia coli ICDH (< 20%). However, it was found that the amino acids implicated in substrate binding, deduced from the 3-dimensional structure of the E. coli NADP-ICDH, appear to be conserved in all the deduced eukaryotic ICDH proteins reported until now.
Amino Acid Sequence↗
Pain due to bone insufficiency as a symptom heralding femoral neck fracture.
Although falls are a major factor in the occurrence of femoral neck fractures, their type and frequency have not been studied in detail. A few case-reports have demonstrated that bone insufficiency can lead to femoral neck fracture and that some falls occur as a result of acute pain preceding the fracture. Estimations of the proportion of femoral neck fractures due to bone insufficiency have ranged from 3% to 24%. We conducted a clinical study of 51 patients with recent femoral neck fractures (46 women and 5 men; mean age, 80.6 +/- 9.3 years). Of the 38 patients who fell from the standing position, three (5.9%) experienced acute pain before the fall. Five patients (9.8%) reported trivial trauma and eight (15.7%) no trauma. Twenty-three patients (45.5%) had hip pain during the weeks preceding the fracture; in 20 cases, the pain was located only to the hip that was subsequently fractured. Features associated with spontaneous fracture were pain during the preceding weeks (7/8; p<0.01), gradually worsening pain (6/7; p<0.02), pain in the inguinal or crural area (6/7), and recent onset of pain (< 3 months) (5/7). We believe that the incidence of bond insufficiency as a cause of femoral neck fracture has been substantially underestimated as a result of diagnostic difficulties and of the usually moderate severity of prefracture pain. Improved knowledge of prefracture symptoms provided by a prospective study may allow appropriate treatment by elimination of weight-bearing, avoiding a substantial number of femoral neck fractures.
Absorptiometry, Photon↗
Alpha-interferon for chronic active hepatitis B in human immunodeficiency virus-infected patients.
OBJECTIVES: A pilot study was conducted to evaluate the efficiency of alpha-interferon treatment in chronic active hepatitis B in anti-HIV-positive patients. METHODS: Twenty-five patients with chronic active hepatitis (23 men and 2 women, mean age: 33 years) were included in the study. Viral infections were acquired by intravenous drug addiction in 2, homosexual relations in 22, and multiple heterosexual contacts in one. The mean CD4 cell count was 480 +/- 234/mL, 7 patients had p24 antigenemia, but none belonged to class C of the CDC classification. All patients were serum HBs Ag and HBV DNA-positive, and delta antigen and antibody negative. Patients received a 6-month course of alpha-interferon 2a, 6 MU subcutaneously three times per week. The mean follow-up after treatment was 15 months. Eighteen patients with serum anti-HIV antibodies, HBsAg and HBV DNA-positive, and chronic active hepatitis, who were not treated with interferon, were included as controls (mean follow-up: 29 months). RESULTS: Nine of the 25 patients (36%) lost serum HBV DNA (1, 2, 4, 6, and 8 months after the beginning of treatment in 1, 4, 1, 2 and 1 cases, respectively), and were considered responders. Only one of the responders developed serum anti-HBe during follow-up, despite the disappearance of HBe Ag in 2 and of HBs Ag in one. Loss of HBV DNA was not clearly associated with the immune status, since 3 of the 9 responders had p24 antigenemia and the 9 responders had a lower mean CD4 count (283 +/- 246/mm3) than non responders (454 +/- 437/mm3, NS). Three of the 18 patients (16.7%) in the control group had spontaneous loss of serum HBV DNA during follow-up. Thus, there was a 2.15-fold increase in HBV DNA loss in the anti-HIV-positive patients who received alpha-interferon, compared to those who did not. CONCLUSION: In HIV-positive patients treated with alpha-interferon, the rate of HBV DNA loss was not clearly different from that reported in immunocompetent patients. As severe HBV-related liver disease has previously been described in anti-HIV positive patients, at least in drug users, these results suggest that this treatment may be proposed whatever the immune status, at least in the absence of AIDS.
Adult↗
Uptake of exogenous DNA by rat liver: effect of cationic lipids.
We have investigated by using centrifugation methods, the uptake and the intracellular fate of 35S DNA by rat liver and the effect on these processes of N-(1-(2,3-dioleoxyloxy)propyl)-N,N,N,-trimethylammonium-methyl-sul fate(DOTAP, Boehringer, Mannheim, Germany), an artificial cationic lipid frequently used in transfection experiments. Labeled DNA molecules are quickly taken up by the liver but a progressive degradation takes place with time. Subcellular distribution of the radioactivity was established after differential and isopycnic centrifugation. Results indicate that 35S DNA enters liver cells by endocytosis and reaches lysosomes. The uptake of 35S DNA is not modified if the molecule is associated with DOTAP but marked differences are observed after internalization of the macromolecule. When DOTAP is used, radioactive products remain for a long time in low density organelles distinct from lysosomes indicating that the transfer of internalized DNA to these organelles is delayed by the cationic lipid. These results suggest that cationic lipids could favor transfection by preventing the delivery of DNA to lysosomes, allowing these molecules to be kept intact and available for transfer from endosomes to cytosol for a long time.
Animals↗
Monocotyledonous C4 NADP(+)-malate dehydrogenase is efficiently synthesized, targeted to chloroplasts and processed to an active form in transgenic plants of the C3 dicotyledon tobacco.
Chloroplastic NADP(+)-malate dehydrogenase (cpMDH, EC 1.1.1.82) is a key enzyme in the carbon-fixation pathway of some C4 plants such as the monocotyledons maize or Sorghum. We have expressed cpMDH from Sorghum vulgare Pers. in transgenic tobacco (Nicotiana tabacum L.) (a dicotyledonous C3 plant) by using a gene composed of the Sorghum cpMDH cDNA under the control of cauliflower mosaic virus 35S promoter. High steady-state levels of cpMDH mRNA were observed in isogenic dihaploid transgenic tobacco lines. Sorghum cpMDH protein was detected in transgenic leaf extracts, where a threefold higher cpMDH activity could be measured, compared with control tobacco leaves. The recombinant protein was identical in molecular mass and in N-terminal sequence to Sorghum cpMDH. The tobacco cpMDH protein which has a distinct N-terminal sequence, could not be detected in transgenic plants. Immunocytochemical analyses showed that Sorghum cpMDH was specifically localized in transgenic tobacco chloroplasts. These data indicate that Sorghum cpMDH preprotein was efficiently synthesized, transported into and processed in tobacco chloroplasts. Thus, C3-C4 photosynthesis specialization or monocotyledon-dicotyledon evolution did not affect the chloroplastic protein-import machinery. The higher levels of cpMDH in transgenic leaves resulted in an increase of L-malate content, suggesting that carbon metabolism was altered by the expression of the Sorghum enzyme.
Amino Acid Sequence↗
Incidence and prevalence of hepatitis B in France.
Reporting of hepatitis B is not compulsory in France, but it is estimated that 8500-9000 acute cases and 100,000 hepatitis B infections occur every year. Seroprevalence studies have been carried out in selected populations. Every blood donation is screened for HBsAg, alanine aminotransferase elevation and anti-HBc antibody. Prevalence of HBsAg has declined from 13.9 positive donations in 1986 per 10,000 to 5.3 in 1991. In pregnant women, overall seroprevalence is estimated at 0.8-1%, which represents more than 5000 children born each year to carrier mothers. Screening of HBsAg for all women when six months pregnant is now compulsory. Heterosexual patients at STD clinics were shown to have a very high risk of being infected with hepatitis B virus, with a chronic carrier rate of 4-5%. In hospital employees before the introduction of vaccination, the overall incidence of hepatitis B was 100-300 acute cases per 100,000 employees per year. Risk varied according to exposure to blood; the highest incidence was found in nurses in dialysis wards. Vaccination against hepatitis B is now compulsory for all hospital and laboratory workers and medical and paramedical students. In preventive medicine consultants, routine medical check-up showed an overall HBV prevalence of 2.2% and a carrier rate of 0.3% in men and 0.1% in women. Immunization of all newborns and adolescents has recently been adopted in France, vaccination at school of adolescents aged 10-11 years being the main target.
Blood Donors↗
[Coronavirus infection in infants: lower respiratory tract involvement, apnea and sudden death?].
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Apnea↗
Radioimmunoassay for plasma histamine: a study of false positive and false negative values.
In order to achieve a correct diagnosis of drug anaphylaxis using a radioimmunoassay devoid of interferences, we have studied factors leading to false positive or false negative values of plasma histamine. Different steps in sample collection were studied systematically in 30 normal volunteers. False positive values were found in haemolysed samples, with histamine concentrations being correlated with haemoglobin concentrations, and where plasma was aspirated from the white-cell layer. There was no significant increase when a tourniquet or vacuum tubes were used, or when blood tubes were left at 4 degrees C overnight. In 12 patients who experienced an anaphylactic reaction, histamine disappeared from blood 10 times more slowly than expected. False negative values were found in two pregnant women and one heparinized patient. Histamine was remarkably stable in vitro in blood or plasma samples, whereas it disappeared rapidly when plasma from a pregnant woman or a heparinized patient was added to the sample. We conclude that false positive and false negative values are rare when using this radioimmunoassay.
Adolescent↗
Immunogenetic determinants and prediction of IDDM in French schoolchildren.
Islet cell antibodies (ICAs) are predictive markers of the disease in first-degree relatives of patients with insulin-dependent diabetes mellitus (IDDM). The large majority of newly diagnosed cases, however, will develop in children with no family history of diabetes. In France, the risk for development of IDDM up to the age of 20 years is 60 times higher in first-degree relatives than in the general population. The aim of this study was to test whether data collected in the first-degree relatives of IDDM patients could be transferred to children for the prediction of overt diabetes. A large population-based cohort of French school-aged children (n = 13,380; ages 6-17 years) were screened for ICAs, and results were compared with those of 1,185 first-degree relatives of IDDM patients. ICA prevalence rates were significantly different in the two populations (5.5% vs. 1.5%; P < 0.0001), with a significantly higher proportion of high ICA titers in first-degree relatives (37%) than in schoolchildren (14%) (P = 0.0005). ICA titers remained remarkably stable in children over 4 years. Insulin autoantibodies (IAAs) were found in 3.4 and 15.4% of ICA+ children and first-degree relatives, respectively. Susceptibility alleles at the human leukocyte antigen (HLA)-DQB1 locus were observed significantly more frequently in children in whom ICA titers > or = 20 Juvenile Diabetes Foundation units (JDF U) were found on two separate occasions (67%) than in ICA- children (52%) (P = 0.05). Five subjects developed overt diabetes during follow-up. ICA titers of > 20 JDF U were found in all of them on the first sample and at follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Antibodies against bovine albumin and other diabetes markers in French children.
OBJECTIVE: Findings in epidemiology and animal experimentation suggest that autoimmunity in insulin-dependent diabetes mellitus (IDDM) may be triggered by dietary cow-milk protein, particularly bovine serum albumin (BSA). Elevated IgG anti-BSA antibodies were found in children from Finland with newly onset diabetes; Finland has the highest incidence of diabetes and cow's milk consumption in the world. We now analyze BSA serology and other diabetes markers in school-age children from France, where diabetes incidence and cow's milk consumption are low. RESEARCH DESIGN: Sera were obtained from three groups: newly diagnosed diabetic (n = 43), islet cell antibody-positive (ICA+) nondiabetic (n = 98), and ICA- healthy control children (n = 267). IgG anti-BSA antibody levels were measured blindly using particle concentration fluoroimmunoassays and analyzed in comparison with ICA titers and human leukocyte antigen-DQB genotypes. RESULTS: There were highly significant differences in BSA antibody levels between all three groups (P < 0.0001). Diabetic patients had elevated anti-BSA levels in 74.4% of cases, compared with 5.5% of control children. In the group of ICA+ non-diabetic children, 20% were anti-BSA-positive. Neither ICA nor BSA antibody titers were significantly related to DQB genotype or sex. ICA titers ( > or = 4 Juvenile Diabetes Foundation units) were present in 84% of diabetic children. Two-thirds of diabetic children were positive for both ICA and anti-BSA antibodies, and none were negative for both markers. CONCLUSIONS: Elevated IgG anti-BSA levels are associated with IDDM in the low-incidence French population. In newly diagnosed diabetic children, these antibodies have similar specificity (95 vs. 98%) and slightly lower sensitivity for IDDM than ICA (74.4 vs. 83.7%). Our results may support an immunological role of BSA in diabetic autoimmunity.
Adolescent↗