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Biomedical subjects

L Robert

Publications and source records attributed to L Robert.

At least 199 records · Page 11Linked to original sources
PubMed1985

Increasing prevalence of HTLV-III infection in intravenous drug users in Liguria, Italy.

Anti-HTLV III prevalence has been investigated in serum samples of 638 intravenous drug users collected over May 1981 - March 1985 and stored at -20 degrees C. Separately, in a prospective way, we have studied 68 IV drug abusers (53 Genoese and 15 of Sanremo area) of whom we have collected, at least, one serum specimen for each year, starting with 1981. We have also tested for anti-HTLV III presence serum samples of: 91 subjects of Hospital staff (Infectious Diseases Department and Laboratory workers); 32 workers in Therapeutic Communities for drug users and 24 family contacts of anti-HTLV III positive drug users. And then serum samples of two groups of general population collected for other seroepidemiological investigations in 1982 (256 subjects) and 1984 (538 subjects) were tested. No IV drug user was positive in 1981 whilst from 1982 up to 1984 there was a strong rising of the prevalence of anti-HTLV III positive subjects: 2, 22, and 39 per cent, respectively. The prevalence remained about 40% in the first months of 1985. The investigations carried out also show that HTLV III spread in Sanremo area slightly before than in Genoa and neighbourhood. No subject positive for anti-HTLV III has been detected among the Hospital staff and in workers of Therapeutic communities who have more probability to get in contact with infected subjects or their blood, as well as in the general population. A positive case has been discovered in a family contact (the wife of a positive for anti-HTLV III IV drug user). Some epidemiological and public health questions linked to the situation observed, at present, in Liguria, are discussed.

Antibodies, Viral↗
PubMed1985

Comparative distribution patterns of type I and III collagens and fibronectin in human arteriosclerotic aorta.

The distribution patterns of type I and III collagens and fibronectin were studied in arteriosclerotic lesions of human aortas as well as in the regions devoid of any macroscopic lesions of the same aortas. Frozen sections were analyzed for fibronectin and collagens by indirect immunofluorescence or immunoperoxidase analysis with specific antisera prepared in rabbits against human plasma fibronectin and against human type I and III collagens. Tissue samples were also stained for type I and III collagen distribution using Picro Sirius red according to the method described by Junqueira et al. (1979). In the regions devoid of any visible macroscopic lesions, there is a co-distribution in the media of the aortic wall of type I and III collagens, with a predominance of type I collagen. Type I collagen is also visible in the intima, as a continuous layer. This is attributed to an age-dependent change of the aorta (arteriosclerosis). Fibronectin can be demonstrated as a thin layer in the subendothelium and as a weak immunofluorescence over the media. In recent or evolutive arteriosclerotic plaques, fibronectin and type III collagen appear to be strongly increased and superimposed. There is also an increase of type I collagen in the intimal region of the plaque. The co-distribution of type III collagen and fibronectin in the arteriosclerotic plaques may suggest a tissue-repair-type of process, analogous to that which can be observed during wound healing. Our results suggest that in arteriosclerotic lesions, type III collagen and fibronectin are predominantly synthesized.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1985

On the influence of the substrate (elastin) in elastase-alpha 1 antitrypsin interactions.

Evidence is presented showing that elastin(s) influences the interactions between porcine pancreatic elastase and its main plasma inhibitor alpha 1-proteinase inhibitor (e.g. alpha 1 antitrypsin). The rate constant of association (kon) between the proteinase and alpha 1 antitrypsin is decreased from 2.8 10(5) M-1 sec-1 to 1.24 10(5) M-1 sec-1 in presence of 1 mg/ml of insoluble elastin and 0.83 10(5) M sec-1 in presence of the same concentration of alpha-elastin. With both elastins this kon decrease was found concentration dependent indicating that these compounds compete in a similar fashion with alpha 1 AT for the binding of elastase. Such an effect was not observed when elastin(s) was replaced by bovine serum albumin. Experiments were designed as previously published (B. Robert et al. 1974) in order to evaluate the capacity of alpha 1 AT to inhibit preadsorbed elastase on to insoluble elastin and also diffusible protease molecules. It was found that even at concentrations far exceeding the equivalence with elastase, alpha 1 AT was only partially able to inhibit both preadsorbed enzyme (approximately 50 per cent) and diffusible protease (approximately 90 per cent).

Animals↗
PubMed1985

Effect of colchicine on atherosclerosis. I. Clinical and biological studies.

The effect of colchicine was studied in 51 hypertensive subjects with several other vascular risk factors. Colchicine was administered for 3-4 months in a daily dose of 1 mg per os. The treatment did not change the lipid content in the blood and in skin biopsies, and had no effect on systolic and diastolic blood pressure. On the contrary, colchicine treatment significantly improved the conjunctival biomicroscopy score, the duration of the dicrotic wave and the peripheral resistance index. The results show the improvement of the microcirculatory parameters (elasticity of arteries) without changes of serum and tissue lipid parameters in the patients treated with colchicine.

Adult↗
PubMed1985

Effect of colchicine on atherosclerosis. II. Biochemical studies on skin biopsies from patients treated perorally with colchicine.

The biosynthesis of proteins and glycosaminoglycans (GAGs) was determined in skin biopsies from atherosclerotic patients treated perorally for 3 months with 1 mg/day colchicine. The biopsies were incubated with 3H-glucosamine and 14C-proline for 5 h and subsequently digested with pronase. In an aliquot of the pronase digest, the specific radioactivity of 14C-proline and 14C-hydroxyproline were determined. The 3H-glucosamine-labeled GAGs were identified by specific enzymic assay and quantified after electrophoretic separation. 3 months treatment with colchicine did not modify the total amounts of proline and hydroxyproline in skin proteins, but diminished the amount of the GAGs as expressed by uronic acid content. Colchicine treatment decreased also the specific radioactivity of proline and hydroxyproline, which reflects a decrease of total protein and collagen synthesis. The incorporation of 3H-glucosamine in the 3H-GAGs was also decreased, mainly in hyaluronic acid. These results suggest that peroral administration of colchicine modifies the synthesis of extracellular matrix proteins and polysaccharides by skin fibroblasts.

Adult↗
PubMed1985

Effect of colchicine on atherosclerosis. III. Study of dermal elastic fibers by quantitative histochemistry, automated image analysis.

Computerized automatic-image analytical procedure was applied on dermal biopsies stained for elastin by a new procedure giving a completely white background and staining only the elastic fiber system. In arteriosclerotic hypertensive patients, a 3-4 months' treatment with 1 mg colchicine per day resulted in a significant (60-80%, p less than 0.01) increase of the dermal elastic fiber density both in the superficial papillary dermis and in the deep dermis. This result shows that the age-dependent increase of elastic fibers can be influenced by pharmacological means. The inhibition by colchicine of the synthesis and secretion of the fibroblast-derived metalloelastase-type protease could be a plausible explanation of this finding.

Adult↗
PubMed1984

Ultrastructural and biochemical modifications of rabbit arteries induced by immunization with soluble elastin peptides.

Immunization of rabbits with soluble elastin peptides (kappa 1-elastin) in complete Freund's adjuvant resulted in morphological and biochemical modifications in aorta and in lung arterioles. The elastic fibers of both tissues appeared fragmented at the light microscopical and ultrastructural levels. The presence of IgG at the site of lysed elastic fibers could be evidenced by immunological techniques. In agreement with these findings, a significantly increased elastase-type protease activity could be demonstrated in aorta extracts from the immunized animals as compared to those obtained from control animals. The biosynthetic activities of aorta explants of rabbits immunized with kappa 1-elastin maintained in organ culture conditions were considerably reduced, as shown by the decrease of incorporation of [14C]lysine and [14C]glucosamine in aorta macromolecules. These results show that anti-elastin antibodies may well be involved in the pathological modifications of the arterial wall and especially in the triggering of the degradation of elastic lamellae.

Animals↗
PubMed1984

Elastase-type activity, elastase inhibitory capacity, lipids and lipoproteins in the sera of patients with ischemic vascular disease.

Elastase-type activity and elastase inhibitory capacity were determined in the sera of 130 atherosclerotic patients, suffering from ischemic vascular disease (IVD) localized at various sites, and of 60 control subjects. The concentrations of serum lipoprotein constituents (triglycerides, total cholesterol, HDL cholesterol, apo-A, apo-B) have also been investigated. HDL cholesterol and apo-A levels were decreased at every site on IVD. Plasma HDL concentration in men was lower than that in women. There was a sex-related difference in the elastase-type activity of the sera: within every atherosclerotic group, elastase-type activity in women was significantly higher than in men. Elastase-type activity did not appear to vary with age and did not show any correlation with the concentration of serum lipoprotein constituents. Pancreatic elastase inhibitory capacity of sera was significantly elevated in the sera of atherosclerotic patients. There was a significant negative correlation between the inhibitory capacity and the HDL cholesterol and apo-A content of sera, respectively. Inhibitory capacity did not show sex-, or age-related variation. There was a significant positive correlation between elastase-type activity and elastase inhibitory capacity measured in control sera. In the sera of atherosclerotic patients this correlation could not be established.

Adult↗
PubMed1984

Interaction between elastin and elastases and its role in the aging of the arterial wall, skin and other connective tissues. A review.

Elastic fibers are progressively lysed during maturation and aging and in an accelerated fashion in several aging diseases such as diabetes, arteriosclerosis, emphysema and several skin diseases. Several enzymes (elastase-type proteases) were isolated in recent years in our laboratory which appear to be involved in these processes. A cell membrane bound serine protease was isolated from arterial smooth muscle cells and was shown to increase with in vitro aging of the cells. A metallo-protease was isolated from skin fibroblasts and was shown to be capable of attacking the constituents of elastic fibers, mainly the microfibrillar glycoproteins and also the desmosine cross linked elastin in vivo. This partially purified fibroblast enzyme was shown to attack these elastic fibers when injected into the dermis. A new selective staining procedure was used to visualise and quantitate, by computerized image analysis, the skin elastic fibers in normal and pathological human or animal skin biopsies. This method, combined with the injection of elastase in rabbit skins, alone or together with inhibitors, enables the ex vivo/in vivo study of elastase action (and of its inhibition).

Adult↗
PubMed1984

Modifications of fibronectin in age-related diseases: diabetes and cancer.

Fibronectin is present in tissues and also in body fluids (plasma). Both forms were studied in normal controls, diabetics and cancer patients; both of these diseases show an age-dependent increasing trend. Age-dependent variations were shown to occur for both forms of fibronectin. Plasma fibronectin increases exponentially with age in a normal population. This increase is strongly attenuated or absent in diabetics and in mammary cancer patients. On the contrary, tissue fibronectin increases in diabetic skin. In mammary cancer fibronectin disappears from the tumor cell membranes but increases in the peritumoral stroma. The above modifications may be attributed to increased protease activity in tumour tissue and also to the possibility of an increased retention of plasma fibronectin in diabetic skin and peritumoral stroma, both tissues exhibiting a modification of intercellular matrix biosynthesis which does involve the increased production of retention sites of fibronectin. An increased local synthesis in both tissues may also occur. The above results are confronted with those reported by other authors and support the contention that plasma and tissue fibronectins undergo age-dependent modifications which may be seriously perturbed in diabetes and cancer.

Adolescent↗
PubMed1984

On the presence of a metalloprotease in human skin fibroblasts that degrades the human skin elastic fiber system.

Succinyl-trialanine paranitroanilide, a specific synthetic substrate of elastases, was shown to be hydrolyzed by Triton X-100 extracts of human skin fibroblasts at near neutral pH. The neutral endopeptidase has been partially purified by ion exchange chromatography (DEAE Sephadex) and affinity chromatography using an AH-Sepharose (Ala)3 column. The enzyme has been purified 85-fold and appears to be a metalloprotease as shown by its inhibitory profile. In its partially purified form, the neutral endopeptidase was found inactive toward benzoyl arginine paranitroanilide, benzoyl tyrosine paranitroanilide, azocasein, type I collagen, and [3H]ligamentum nuchae-insoluble elastin. Structural glycoprotein microfibrils isolated from porcine aorta are extensively degraded by this neutral protease. It could also hydrolyze, but to a lesser extent, insoluble elastin purified from human aortas; it was, however, found inactive toward bovine ligamentum nuchae elastin. Its potentiality to degrade the human skin elastic fiber system (namely elastic fibers, oxytalan, and elaunin fibers) has been assessed by a morphometric analysis of the length of these fibers (on tissue sections appropriately stained to identify the components of the elastic fiber system) prior to and after enzyme action. Analysis of the data obtained by morphometry indicated that this neutral protease attacked rapidly both elaunin and oxytalan fibers of human dermis, but only slowly the mature elastic fibers.

Cells, Cultured↗