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Biomedical subjects

M Chevallier

Publications and source records attributed to M Chevallier.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Variation, variability of blood pressure. Study techniques].

Blood pressure (BP) is not a constant parameter, but exhibits variations, which involve a change in its value with time, and variability, which corresponds to the extent of this variation. A circadian pattern of BP, with higher values during the day than at night, is one expression of this variation in BP. This variation corresponding to the circadian pattern is dependent on both physical constraints and psychosensory factors. Investigation of variability implies consideration of both long-term and shorter term changes in BP. Long-term variability can be assessed by ambulatory determinations of BP, which can be carried out at intervals of 1/4 hour. This variability can be used to define the daytime/nighttime alteration of the circadian cycle, with the possible absence of the nocturnal reduction in BP or even a reversal of this circadian pattern. An abnormality of this type would be of prognostic importance, particularly in terms of impact on the left ventricle. Medium- or above all short-term variability can be assessed only from the change in beat/beat difference in BP and heart rate (HR) which depends on vagal tone and the orthosympathetic system. This variability can be detected by invasive methods and, more recently, using non-invasive methods (Finapres). It would seem that changes in this variability may reveal a defect in baroreceptor control which it is useful to identify for both diagnostic and therapeutic purposes.

Aging↗
PubMed1993

[Evaluation of the aging change in cardiac autonomic nervous system by automated clinical measurement].

The object of this study was to establish normal values for age of clinical tests of autonomic nervous system activity based on an automatic measuring system. Ninety-seven subjects (50 M/47 F) aged 20 to 85 years (average 45 +/- 13 years) with a normal clinical examination and no medication were included in the study. The blood pressure (BP) and heart rate (HR) were measured continuously with the Finapres system. After a resting period, the BP and HR were measured continuously in 5 different situations: dorsal decubitus position for 7 minutes; on getting up actively in less than 3 seconds and for 9 minutes in the upright positions, during deep breathing at 6c/min and Valsalva manoeuvre during a handgrip test at 30% of maximal voluntary strength for 3 minutes. A specific programme (ISN-CNRS) initiated the calculations of the test and performed direct and crossed spectral analysis in the lying and standing positions. The average BP was 120 +/- 18/66 +/- 11 mmHg and HR was 67 +/- 9 b/min. A negative linear correlation was observed with age with respect to the 3 tests investigating vagal activity: 30/15 ratio, spontaneous variations of respiration and HR, ratio of HR at the end of Valsalva with r = -0.43, r = -0.60, r = -0.34 (p < 0.001). The other two tests: variation of systolic BP 1 min 30 after standing and variation of diastolic BP during the handgrip did not change with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Interferon-alpha 2b therapy reduces liver fibrosis in chronic non-A, non-B hepatitis: a quantitative histological evaluation.

The aim of this study was to evaluate the effect of interferon-alpha on liver fibrosis with an established quantitative histochemical method for determining collagen as a marker. 59 patients (31 men, 28 women; 47 +/- 14 yr) with chronic non-A, non-B hepatitis (92% with hepatitis C virus antibody) received subcutaneous injections of 3 or 1 MU recombinant interferon-alpha 2b or placebo thrice weekly for 24 wk. Needle-biopsy sections taken before and after interferon treatment were examined for histological evaluation and collagen quantitation. Values were compared with results obtained by means of morphometrical analysis of liver collagen and Knodell scoring histological index. The index of periportal and/or bridging necrosis was the only component of Knodell's histological score significantly decreased (p < 0.05) in patients treated with 3 MU interferon compared with placebo-treated controls. The fibrosis score was not significantly changed. In contrast, liver total collagen variations measured colorimetrically and morphometrically were significantly decreased in patients treated with 3 MU and 1 MU compared with the increase observed in the placebo-treated controls (p < 0.05). From these results, we conclude that a 6-mo course of 3 MU or 1 MU interferon-alpha 2b causes slight but nonetheless significant regression of liver fibrosis as assessed on the basis of quantitative estimation of liver collagen, irrespective of other response criteria, whereas progression of liver fibrosis can be observed in the absence of treatment.

Adult↗
PubMed1992

Cell populations in the lesion of human cutaneous leishmaniasis: a light microscopical, immunohistochemical and ultrastructural study.

To characterize the in situ cellular immune response in localized cutaneous leishmaniasis (LCL), the authors studied frozen skin biopsies from 50 patients with LCL due to Leishmania braziliensis guyanensis. A panel of 31 monoclonal antibodies was used, which defined the number and distribution of inflammatory cell subsets. Skin inflammatory infiltrates were composed of T cells (with a local CD4/CD8 ratio of 1.05 +/- 0.7 vs 1.48 +/- 0.3 in peripheral blood), macrophages and a smaller number of B cells, natural killer cells and granulocytes. Most of the T cells expressed activation markers (interleukin-2 and transferrin receptors, HLA-DR+) and an increase in T-cell-receptor gamma delta expression was noted. Analysis of the CD4+ subpopulations with newly available reagents showed that helper T cells (CD4+CD45RO+) exceeded the suppressor/inducer subset (CD4+CD45RA+) by 1.4:1. There were no differences between local immune variables from patients with primary infection (45 patients) and those with recurrence (5). In 7 patients, biopsies were analysed before and 1 month after specific treatment, and did not show significant differences except for a small increase of dermal CD1a+ (Langerhans) cells/mm2. The observed pattern of cellular skin infiltration suggests an immune-mediated tissue injury including T-cell-mediated cytotoxicity and delayed hypersensitivity reactions in addition to direct parasitic action.

B-Lymphocytes↗
PubMed1992

Morphological aspects of early and late collagen degradation in granulation tissue.

A sequential histologic, ultrastructural and immuno pathologic study was carried out in the Selye's inflammatory pouch model to observe extracellular matrix and cellular changes during granulation tissue formation. Besides changes involving different components of the connective tissue, it was observed that collagen resorption occurred under a biphasic process. At an early phase (3rd to 15th day), in which exudative inflammatory changes predominated, signs of collagen synthesis and degradation were seen simultaneously. Extracellular breakdown and internalization of collagen fragments within fibroblasts and myofibroblasts were observed. Later on (30th to 60th day), changes affecting collagen had a different ultrastructural appearance. Collagen fragmentation, focal "lytic" and "electron dense" changes occurred in the extracellular space specially at the periphery of fibroblasts, myofibroblasts and smooth muscle cells. Collagen degradation, thus seems to be a continuous process in granulation tissue, occurring with different morphologies at different times.

Animals↗
PubMed1992

[Liver damage induced by the ingestion of a product of phytotherapy containing wild germander. Four cases].

We report 4 cases of patients who developed hepatic injury during administration of herbal medicines for loosing weight with Wild Germander. Three developed jaundice and one had fatigue. Aminotransaminase activities were increased in all patients. Outcome was favorable after drug withdrawal in all patients. Liver biopsy showed centrolobular necrosis and portal lymphoplasmocytic infiltration. Another drug than Wild Germander might have been implicated in hepatic injury in two patients. The similarity of these cases suggests, however, that Wild Germander, like other herbal medicines, may be responsible for hepatic injury.

Acute Disease↗
PubMed1992

[Recovery of chronic hepatitis B- delta infection by zidovudine and recombinant interferon alpha combination therapy in a patient with Kaposi's sarcoma associated with HIV infection].

A 39 years old homosexual male suffering from chronic type B hepatitis superinfected by HDV, and positive for anti-HIV1 was treated with zidovudine associated with high doses of recombinant interferon alpha for onset of an extensive cutaneous Kaposi sarcoma. Other than the long-lasting disappearance of Kaposi's lesions, this therapy was followed by complete recovery from hepatitis B and D. Serological and hepatic clearance of both viruses was marked by two successive cytolytic peaks separated by a 9 month interval. The patient's immunologic status has remained stable at 30 months. To our knowledge, such a success had never been reported in the literature and the clearance of both hepatitis B and D viruses in an AIDS patient stands in sharp contrast with the usual rapidly progressive evolution of those triple coinfections. This phenomenon illustrates the potential benefits of zidovudine in association with high dose of interferon alpha in HIV patients suffering from hepatitis D.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Comparison of 1 or 3 MU of interferon alfa-2b and placebo in patients with chronic non-A, non-B hepatitis.

Ninety patients with histologically documented chronic non-A, non-B hepatitis were randomly allocated to receive SC injections of placebo or of 1 or 3 MU of recombinant interferon alfa-2b three times weekly for 24 weeks. Complete normalization of alanine aminotransferase levels occurred posttreatment in 43.3% of patients receiving 3 MU, in 20% of those receiving 1 MU, and in 6.7% of untreated patients (P less than 0.0005 vs. those treated with 3 MU). Alanine aminotransferase normalization was sustained for 6 months after therapy in 13.3% of the patients treated with 3 MU and in 3.3% of those given 1 MU or placebo. The decline of alanine aminotransferase levels following interferon therapy showed independent, positive correlations with female sex (P less than 0.03) and younger age (P less than 0.05). The Knodell's fibrosis score was strongly positively correlated with age (P less than 0.0001). It is concluded that 3 MU of interferon is a more effective dose than 1 MU for controlling disease activity in non-A, non-B chronic hepatitis patients. Women and younger and noncirrhotic patients are more likely to respond.

Adult↗
PubMed1991

Expression of HLA antigens and T cell infiltrates in chronic viral hepatitis. A comparison of biopsy and fine-needle aspiration findings.

To evaluate the expression of hepatocyte HLA Class I and II antigens and the infiltration of CD8-positive lymphocytes in patients with chronic hepatitis, cells obtained by the technique of fine-needle aspiration were compared with those obtained by percutaneous liver biopsy. In general, correlation between cytological and histological specimens of HLA Class I and Class II antigen expression and CD8 lymphocyte infiltration was excellent when comparing results of the core biopsy expressed semiquantitatively, and results from fine-needle aspiration quantitatively as percentage of cells stained. Although the major potential of multiple fine-needle aspiration sampling probably will be in the surveillance of patients who have received orthotopic liver transplants, the results of this study indicate that fine-needle aspiration can provide a useful technique for following antigen expression and inflammatory changes in studies in which frequent periodic samples may be necessary to monitor efficacy or toxicity of treatment regimens.

Biopsy↗
PubMed1991

Matrix remodelling and fibroblast phenotype in early lesions of human cutaneous leishmaniasis.

The connective matrix participates directly in early pathological events observed in the cutaneous lesion of leishmaniasis, due to Leishmania braziliensis guyanensis. A sample of 19 skin biopsies was examined by light and electron microscopy, in order to identify the matrix components (collagen isotypes I to IV, elastin and membrane associated proteins) of the dermal infiltrate, and the pattern of organization of the reparative connective matrix. An extensive remodelling process of apparently parasite-independent nature involves different fibroblast sub-populations. The original organization of this immune-mediated lesion offers a rare opportunity to study in situ the local inflammatory mediators inducing the activation of fibroblasts and macrophages.

Adolescent↗
PubMed1991

Azathioprine induced liver disease: nodular regenerative hyperplasia of the liver and perivenous fibrosis in a patient treated for multiple sclerosis.

Azathioprine hepatotoxicity has been described mainly in renal transplant recipients. Most reported cases are related to lesions of the venous system of the liver: peliosis hepatis, veno-occlusive disease of the liver, perisinusoidal fibrosis, and nodular regenerative hyperplasia of the liver. The most common clinical manifestation of these hepatic vascular lesions is portal hypertension. We present a case of nodular regenerative hyperplasia and perivenous fibrosis in a patient receiving azathioprine for multiple sclerosis. Histological abnormalities were similar to those described in renal transplant patients, and azathioprine was the only potential hepatotoxic agent present.

Adult↗
PubMed1990

Elastin in human, baboon, and mouse liver: an immunohistochemical and immunoelectron microscopic study.

Light microscope histochemistry and immunohistochemistry, and routine electron microscopy techniques were performed to analyse elastin distribution and structure in the human liver compared with that in baboon and mouse. In man and baboon, elastic fibers stained by iron hematoxylin or orcinolnew fuchsin seemed to be solitary and were few in number; in the mouse they were thinner but abundant, both in the portal tract and in hepatic veins. Orcein or resorcin-fuchsin stains, employed after oxidation of tissue sections, revealed a network comprising elastic, elaunin, and oxytalan fibers, which was also demonstrated by immunofluorescence with anti-elastin antibody in man and baboon. At the ultrastructural level, the elastic fibers of the human portal tract corresponded to discontinuous patches of amorphous material intermingled with few microfibrils. These contrasted with the thinner elastic fibers of baboon and mouse liver which had a core of amorphous material. In man and baboon, these fibers meshed into slender bundles of microfibrils often exhibiting small spots of amorphous material (elaunin fibers) and terminated as isolated microfibrils (oxytalan fibers). Immunoelectron microscopy of elastin carried out on baboon liver tissue labelled the amorphous material and also its microfibrillar component. Immunoperoxidase deposits were also associated with isolated bundles of microfibrils in the baboon portal stroma. Immunolabelling and elastic stains disclosed an important elastin portal network located around vascular, biliary structures and interspaced with collagen bundles. The structural polymorphism of elastin, assembling different relative amounts of amorphous material and microfibrils, might have a relationship with the required elasticity in a given species.

Adult↗
PubMed1990

Elastin in alcoholic liver disease. An immunohistochemical and immunoelectron microscopic study.

Increased elastic stained material has been described in fibrotic and cirrhotic liver processes. The aim of this work was to follow the development and distribution of elastic fibers from 48 chronic alcoholic patients. Patients were scored for fibrosis as 0, without fibrosis or minimal (n = 5); 1, incipient or early fibrosis (n = 9); 2, fibrosis or incomplete cirrhosis (n = 12); and 3, cirrhosis (n = 22). Elastica staining was performed by orcein, resorcin-fuchsin and iron hematoxylin and confirmed by immunofluorescence staining with an anti-human elastin antibody (Institut Pasteur). Electron microscopy of representative cases of each group and electron microscopy of immunolabelled elastin (n = 5) were also performed. In early alcoholic fibrosis, oxytalan fibers were pointed out in terminal hepatic veins and in Disse space. In fibrous portal extensions and cirrhotic internodular septa, oxytalan and elaunin fibers represented the major elastin components in association with the alcoholic liver fibroplasia. Immunostaining with anti-elastin Ab exhibits the same distribution as with histochemical methods in portal and septal zones. Electron microscopy confirmed abundant microfibrillar bundles between collagen fibers that mesh and are in continuity with elaunin fibers. Immunoelectron microscopy confirmed elastin deposits in the amorphous material and in association with the microfibrillar material in the portal and septal zones and disclosed elastin even in the thin strands of fibrotic tissue. In conclusion, elastogenesis, mainly represented by oxytalan and elaunin fibers, develops in alcoholic disease and takes part, with collagen deposits, in the fibrotic process.

Collagen↗