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Biomedical subjects

A Bernard

Publications and source records attributed to A Bernard.

At least 181 records · Page 10Linked to original sources
PubMed1997

Phenotyping of intrahepatic and peripheral blood lymphocytes in patients with chronic hepatitis C.

The host immune responses have been suggested to play a role in liver injury occurring in patients with chronic hepatitis C. In order to explore the relationship between the relative proportions of intrahepatic and peripheral blood lymphocytes (IHL, PBL), the levels of viremia, and the histological hepatitis activity score, three-color fluorescence-activated cytometric analysis was performed for 36 patients with chronic hepatitis C and six control subjects without chronic hepatitis. The liver biopsy was performed before any antiviral therapy. Each liver specimen was divided into two parts: one for histological examination and one for immunological analysis. Tricolor CD45 was used to improve "lymphogating." Fluorescein isothiocyanate- or phycoerythrin-conjugated monoclonal antibodies with specificity for CD3, CD4, CD8, and CD20 (lymphocyte subpopulations), for CD69 (activated lymphocytes), and for CD16/56 (natural killer cells) were used. The livers of patients with chronic hepatitis C contained a greater proportion of CD4+ lymphocytes that exhibited marked expression of CD69 than in control subjects (20.7 +/- 7.3% vs 10.2 +/- 4.6%, P = 0.027). Moreover, in patients with chronic hepatitis C, the proportion of CD4+ IHL correlated with the histological hepatitis activity evaluated by the Knodell score (r = 0.48, P = 0.004). No correlation was found between the percentage of CD4+ IHL and the level of viremia or transaminase activities. Our findings clearly indicate that a cellular immune response does take place in HCV-infected livers and could thus contribute to the outcome of hepatitis C virus infection.

Adult↗
PubMed1997

Cytokines secreted by glial cells infected with HTLV-I modulate the expression of matrix metalloproteinases (MMPs) and their natural inhibitor (TIMPs): possible involvement in neurodegenerative processes.

Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) known to be fundamental to normal physiological processes, also contribute to several pathologies associated with uncontrolled tissue degradation. Recent observation of MMPs and TIMPs in the central nervous system suggest they could play a role in the neurodegenerative process following viral infection. We have investigated the expression of these molecules in human and rat glial cells infected with retrovirus HTLV-I, the causative agent of HTLV-I associated myelopathy (TSP/HAM). We report that cytokines secreted by infected glial cells are responsible for the increased expression of MMP-3, MMP-9 and TIMP-3, while MMP-2, TIMP-1 and TIMP-2 remained stable. The role of dysregulated MMPs/TIMPs in the pathogenesis of TSP/HAM may be related to various functions of these proteases, namely degradation of the blood-brain barrier, myelin constituent cleavage and conversion of inactive TNF-precursor to active form.

Animals↗
PubMed1997

Hepatoid adenocarcinoma of the lung: report of a case of an unusual alpha-fetoprotein-producing lung tumor.

We report on a rare tumor of the lung characterized by its morphologic hepatoid features and alpha-fetoprotein production. This unusual neoplasm arose in the left lung of a 36-year-old man in whom clinical and radiologic examinations did not reveal any other tumor. The serum level of alpha-fetoprotein was measured at 6,090 ng/mL and was parallel to the evolution of the tumor. Despite treatment, the patient died 7 months after the diagnosis. The microscopic appearance of the tumor was the same as observed in hepatocarcinoma and hepatoid adenocarcinoma of the ovary or the stomach, with a tubular, papillary, or trabecular pattern. Periodic acid-Schiff-positive hyaline globules were numerous, and tumor cells showed immunohistologic positivity for alpha-fetoprotein and carcinoembryonic antigen. This lung adenocarcinoma was first described by Ishikura et al. in 1990 and was named hepatoid lung adenocarcinoma. Like the rare hepatoid carcinoma of the gallbladder, the pancreas, the ampulla of Vater, the renal pelvis, and the bladder, the exact histogenesis and the prognosis of this type of lung tumor are not yet known.

Adenocarcinoma↗
PubMed1997

Developmentally regulated alternative splicing of mRNAs encoding N-terminal tau variants in the rat hippocampus: structural and functional implications.

Tau protein variants are axonal microtubule-associated phosphoproteins whose expression correlates with developmentally regulated neurite outgrowth. A single gene encodes multiple tau transcripts via complex alternative splicing. We studied the expression of the mRNAs encoding N-terminal variants of tau, and we showed distinct alternative splicing of exons 2 and 3 in nervous tissues of the adult rat, including the inner ear, hippocampus, cortex, striatum, brainstem, cerebellum, olfactory bulb and retina. Using the reverse transcriptase-coupled polymerase chain reaction and in situ hybridization, we then focused our developmental study on hippocampal neurons, both in vivo and in vitro, to address the developmental and spatial expression of the alternatively spliced mRNAs encoding N-terminal variants of tau. Tau mRNAs devoid of exons 2 and 3 were present throughout development, although their levels decreased in adults. Those containing exon 2 but not exon 3 were already present in the hippocampus of newborn rats and their levels increased during the first postnatal week, mainly in the pyramidal cell layer. Tau RNAs containing exons 2 and 3 appeared at the end of this period in the pyramidal cell layer and in the dentate granule cells. Exon 2-containing mRNAs seemed to be associated with cells undergoing axonal sprouting, while exon 3-containing RNAs were expressed in mature neurons that had established their connections. The timing and pattern of tau alternative splicing were maintained in cultured hippocampal neurons, suggesting that splicing processes are independent of the organized connectivity and of the environmental cues provided in vivo. Secondary structure predictions of tau variants revealed that the insertion of the exon 3-encoded domain substantially modifies the secondary structure of the N-terminal region of tau. This N-terminal heterogeneity may confer distinct regulatory roles on the tau variants during ontogeny and may contribute to plasticity in the adult rat brain.

Alternative Splicing↗
PubMed1997

Association of ERK2 mitogen-activated protein kinase with human immunodeficiency virus particles.

Here we report the presence of a protein kinase activity associated with human immunodeficiency virus type 1 (HIV-1) particles. We observed phosphorylation of five major proteins by the endogenous protein kinase activity. Phosphoamino acid analysis revealed phosphorylated serine and threonine residues. In addition, we observed autophosphorylation of two proteins in the presence of gamma-ATP in an in-gel phosphorylation assay. These two proteins are not linked by a disulfide bond, suggesting that two different protein kinases are associated with HIV-1 virions. Our results indicate the presence of ERK2 mitogen-activated protein kinase and of a 53,000-molecular-weight protein kinase associated with virions. Moreover, the use of different HIV strains derived from T cells and promonocytic cells, as well as the use of human T-cell leukemia virus type 1 particles, demonstrates that ERK2 is strongly associated with retrovirus particles in a cell-independent manner. Exogenous substrates, such as histone proteins, and a viral substrate, such as Gag protein, are phosphorylated by virus-associated protein kinases.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Transient increase of serum Clara cell protein (CC16) after exposure to smoke.

OBJECTIVES: Smoke inhalation is a well known cause of airways injury in firefighting personnel. The aim of this study was to evaluate whether toxic effects of smoke on the respiratory tract can be detected by measuring Clara cell protein (CC16), a recently described serum marker of lung function. METHODS: CC16 was measured by a sensitive latex immunoassay in the serum of six voluntary firefighters from a chemical plant who had inhaled smoke from the combustion of polypropylene for about 20 minutes. The protein was measured immediately after the fire and 10 days later. The values were compared with those of six control workers examined simultaneously. RESULTS: The mean (SD) concentration of CC16 in the serum of firefighters after the fire (54.4 (34.9) micrograms/l) was significantly higher than that of controls (19.5 (11.7), P = 0.04). 10 days later, serum CC16 from firefighters had returned to the concentrations found in controls (15.9 (2.76) v 17.7 (12.5)). With the values at day 10 as a baseline, the rise of serum CC16 was estimated at 328% on average (range 100%-564%). These changes were found in the absence of any functional sign of lung impairment. CONCLUSION: Acute exposure to smoke results in a transient increase of CC16 in serum due most likely to an increased permeability of the bronchoalveolar/blood barrier. Serum CC16 seems potentially to be a new biomarker for the early detection of acute airways injury caused by smoke.

Adult↗
PubMed1997

Urinary neutral endopeptidase in workers exposed to cadmium: interaction with cigarette smoking.

OBJECTIVES: Structural impairment of the renal proximal tubular epithelium induced by cadmium (Cd) was investigated by measuring the concentration of neutral endopeptidase 24.11 (NEP), an ectoenzyme of the apical brush border, in the urine of 106 male workers employed in a Cd smelter (among whom 52 were occupationally exposed to Cd), and by comparing it with other tubular markers (low molecular weight proteins, lysosomal enzymes). METHODS: NEP (EC 3.4.24.11), beta-N-acetyl-glucosaminidase (NAG) (EC 3.2.1.30), and NAG-B isoenzyme activities were measured by fluorimetric assays, whereas the concentrations of retinol binding protein (RBP), beta 2-microglobulin (beta 2M), and Clara cell protein (CC16) were measured by automated latex agglutination techniques. RESULTS: An increased urinary excretion of NEP as well as microproteins was found only in subjects excreting more than 5 micrograms Cd/g creatinine. In this group, NEP concentrations were significantly higher in the subjects who smoked. This significant interaction could not be found for any other marker tested. CONCLUSIONS: The data suggest that NEP enzymuria is high even at low exposures to Cd (with a threshold of urinary cadmium excretion (U-Cd) at 5 micrograms/g creatinine), indicating early structural alterations. Moreover, its particular sensitivity to smoking could be useful in the detection of new population clusters potentially more susceptible to development of nephrotoxic insult.

Acetylglucosaminidase↗
PubMed1997

Fatty acid regulation of fatty acid-binding protein expression in the small intestine.

The effects of dietary oil intake and fatty acid infusions on the expression of intestinal and liver fatty acid-binding proteins (I-FABP and L-FABP, respectively) were investigated in the small intestine of mice. A daily force-feeding for 7 days with 0.2 ml sunflower oil specifically increased L-FABP mRNA and protein levels in duodenum and proximal jejunum. This upregulation was mediated in time- and dose-dependent manners by a minute quantity of linoleic acid, the main fatty acid found in sunflower oil. The L-FABP induction was only found with long-chain fatty acids, with the nonmetabolizable, substituted fatty acid alpha-bromopalmitate being far more active. A hormonally mediated effect is unlikely because long-chain fatty acids induced L-FABP mRNA in the Caco-2 cell line cultured in serum-free medium. Therefore, long-chain fatty acids are strong inducers of L-FABP gene expression in the small intestine. In contrast to data found in the rat, I-FABP gene expression appears to be unaffected by a lipid-enriched diet in the mouse.

Animals↗
PubMed1997

Assessment for Subclinical Kidney Damage in Workers Exposed to Low Concentrations of Hydrocarbons.

It has been suggested the risk of hydrocarbon-induced chronic nephropathy is negligible at low exposure levels. The first purpose of the study was to test this hypothesis by selecting a population slightly exposed to hydrocarbons. Moreover, as hypertension might be associated with an increased excretion of nephrotoxic mercapturates, the association between blood pressure and urinary concentration of S-phenylmercapturic acid (S-PMA) was also examined. Lifetime exposure assessment, main tests of subclinical kidney damage, and statistical approach were taken from a previous study that had included primarily moderately or heavily exposed workers and had found hydrocarbon-induced nephrotoxic effects. No nephrotoxic effect of exposure could be ascertained in the present study. S-PMA concentration was not increased in hypertensive workers. Thus, the risk of hydrocarbon-induced chronic nephropathy might be extremely low in workers slightly exposed to hydrocarbons. The negative results of some studies might be due to the low lifetime hydrocarbon exposures of the study populations.

Journal Article↗
PubMed1997

Improved management of invasive pulmonary aspergillosis in neutropenic patients using early thoracic computed tomographic scan and surgery.

PURPOSE: The prognosis of invasive pulmonary aspergillosis (IPA) occurring in neutropenic patients remains poor. We studied whether new strategies for early diagnosis could improve outcome in these patients. PATIENTS AND METHODS: Twenty-three histologically proven and 14 highly probable IPAs in 37 hematologic patients (neutropenic in 36) were analyzed retrospectively. RESULTS: The most frequent clinical signs associated with IPA were cough (92%), chest pain (76%), and hemoptysis (54%). Bronchoalveolar lavage (BAL) was positive in 22 of 32 cases. Aspergillus antigen test was positive in 83% of cases when tested on BAL fluid. Since October 1991, early thoracic computed tomographic (CT) scans were systematically performed in febrile neutropenic patients with pulmonary x-ray infiltrates. This approach allowed us to recognize suggestive CT halo signs in 92% of patients, compared with 13% before this date, and the mean time to IPA diagnosis was reduced dramatically from 7 to 1.9 days. Among 36 assessable patients, 10 failed to respond (amphotericin B [AmB] plus fluorocytosyne, n = 2; itraconazole + AmB, n = 8) and died of aspergillosis. Twenty-six patients were cured or improved by antifungal treatment (itraconazole with or without AmB, n = 22; voriconazole, n = 4). In 15 of 16 cases, surgical resection was combined successfully with medical treatment. Achievement of hematologic response, early diagnosis, unilateral pulmonary involvement, and highest level of fibrinogen value < 9 g/L were associated with better outcome. CONCLUSION: In febrile neutropenic patients, systematic CT scan allows earlier diagnosis of IPA. Early antifungal treatment, combined with surgical resection if necessary, improves IPA prognosis dramatically in these patients.

Antigens, Fungal↗
PubMed1997

Inhibition of tyrosine hydroxylase expression within the substantia nigra of mice infected with canine distemper virus.

Experimental infection of mouse brain with a neuroadapted strain of canine distemper virus (CDV) leads to early acute encephalitis, followed by late neurological diseases such as motor pathologies (paralysis and turning behavior) or obesity syndrome. We have previously shown that, during the early stage of infection, CDV replicates transiently in selective structures of the brain including the substantia nigra, a structure known to play a critical role in motor control. In this study we demonstrate that CDV replication in the substantia nigra induces an early decrease in transcript level of tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis. The CDV infection of neuroblastoma cell culture, constitutively expressing TH, results in downregulation of TH transcription in the absence of cell death. In the few surviving mice with motor deficiencies, a pronounced decrease in TH expression is associated with a loss of dopaminergic cell bodies in the absence of any viral transcripts and proteins, suggesting that the initial CDV infection was sufficient to trigger irreversible neurodegenerative processes.

Animals↗
PubMed1997

Effect of cyclic fatty acid monomers on fat absorption and transport depends on their positioning within the ingested triacylglycerols.

We investigated the intestinal digestion of cyclic fatty acid monomers (CFAM) isolated from heated linseed oil and their effects upon fatty acid lymphatic transport and lipoprotein profile in lymph. These cyclic fatty acid monomers were acylated in specific positions in the glycerol backbone of triacylglycerols (sn-(1/3) position for the 1C oil, sn-2 position for the 2C oil and together in the sn-1,2, and 3 positions for the 3C oil) and administered intragastrically to lymph-canulated rats. Their lumenal digestibility was also assessed in vitro using a pancreatic lipase assay. The lipase activity was 1.9 to 6.6 less towards the triacylglycerols acylated with cyclic fatty acids compared to control. The lowest activity was with the 2C oil. In the hydrolytic products, the cyclic fatty acid contents were similar between the experimental groups. When absorbed as 2-monoacyl-sn-glycerol (2C oil), cyclic fatty acid monomers were better and unselectively recovered into the lymph than when absorbed as free fatty acids (1C oil). In that latter situation, the bulkier cyclic fatty acids (C6 and cis membered-ring CFAM) were transported into the lymph to a lesser extent. The appearance of the lymphatic chylomicrons was delayed in rats fed the 1C oil. Cyclic fatty acid monomers from the 2C oil only increased the lymphatic transport of saturated fatty acids (80%). Cyclic fatty acids from the 3C oil (absorbed as 2-monoacyl-sn-glycerol and free fatty acid) usually elicited intermediary effects. We conclude that the effects of cyclic fatty acid monomers upon the intestinal metabolism are greatly influenced by their positioning within the triacylglycerol and that the structure of the cyclic fatty acids influences their lymphatic recovery only when they are absorbed as free fatty acid.

Animals↗
PubMed1997

Salpêtrière Hospital experience with biochemotherapy in metastatic melanoma.

PURPOSE: This article investigates the safety and efficacy of a simple cisplatin-based biochemotherapy regimen, containing single-agent cisplatin plus recombinant interleukin-2 (rIL-2) and recombinant interferon-alpha (rIFN-alpha), in the treatment of metastatic melanoma. PATIENTS AND METHODS: Between December 1990 and April 1997, 129 patients were treated with cisplatin (100 mg/m2, day 0) plus continuous intravenous infusion rIL-2 (18 MIU/m2/day, days 3-6 and days 17-21) and subcutaneous rIFN-alpha (9 MIU three times per week) plus or minus tamoxifen (160 mg/day) on three different protocols. Tumor response, disease-free survival, and overall survival were evaluated for all evaluable patients (N = 127). RESULTS: The overall response rate was 49%, and 10% of patients achieved a complete response. Responses were observed at all sites of metastases. In one case, a patient with a large cutaneous inguinal mass experienced a dramatic regression of that lesion within 1 month. The median disease-free survival was 5 months, and median overall survival was 11 months. Patients who responded had a significant survival advantage over nonresponders, and patients who achieved a complete response had a significant survival advantage over patients with a partial response. Toxicities were manageable and reversible upon discontinuation of therapy. CONCLUSION: The response rates achieved with this simple biochemotherapy regimen are comparable to those for other cisplatin-based biochemotherapy regimens, which use more complex multiagent chemotherapy regimens. We found no added clinical benefit from the addition of tamoxifen to cisplatin.

Adolescent↗
PubMed1996

Comparative study of human red blood cell analysis with three different field-flow fractionation systems.

An extensive multi-laboratory study was conducted to compare three different field-flow fractionation (FFF) systems for use in the analysis of human erythrocytes. The object of this study was to determine the relationship between the FFF elution properties for each system and the traditional hematological blood cell parameters. One centrifugal system (Utah) and two gravitational systems (Paris and Abbott) were compared. In order to analyze erythrocyte populations with a broad range of hematological indices, blood samples were collected from individuals heterozygous for sickle cell anemia (A/S) and also from normal controls (A/A), and these were analyzed at each site. Identical samples were analyzed by the Abbott and Utah sites. With all three systems, blood samples from each category produced narrow, overlapping distributions of FFF retention ratios, with the Abbott and Utah systems showing slight elevations in the mean retention ratios for the sickle cell samples. Blood cell elution peak characteristics were compared with standard hematological parameters for each of the FFF systems, and negative correlations were consistently found between mean corpuscular volume (MCV) and retention ratios. Positive correlations were found between red cell distribution width (RDW) and retention ratios. Elevated FFF retention ratios were frequently found with blood samples having abnormal hematological profiles. These results demonstrate that the three differently configured systems all produce similar analysis profiles for erythrocytes from the classes studied here. The relationships between FFF parameters and hematological indices were consistent for all systems.

Anemia, Sickle Cell↗
PubMed1996

[Thymic carcinoid tumor causing paraneoplastic Cushing syndrome. Diagnostic value of double-labelled tomoscintigraphy].

Cushing's syndromes caused by ectopic corticotropin secretion represent 10 to 15% in the causes of Cushing's syndrome. Somatostatin receptor scientigraphy can be successful in the localization of ACTH-secreting neuroendocrine tumors. We report a case of Cushing's syndrome caused by ectopic corticotropin secretion from a thymic carcinoid tumor. Conventional localization techniques failed but the tumor was detected by a double binding thoracic scintigraphy using 111Indium-octreotide and 99mTechnetium-albumine macroagregates.

Adult↗