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Biomedical subjects

C Franceschi

Publications and source records attributed to C Franceschi.

At least 307 records · Page 17Linked to original sources
PubMed1986

Prostaglandin and thromboxane biosynthesis in resting and activated platelet-free monocytes from aged subjects.

The main cyclo-oxygenase-dependent arachidonic acid (AA) derivatives, i.e. prostaglandin E2 (PGE2) and thromboxane A2 (TXA2), have been measured by radioimmunoassay in platelet-free cultures of human monocytes from young and old subjects, in presence and in absence of activating substances (10% fetal calf serum). No difference was found between cells from the two groups as far as the production of PGE2 and TXB2 (stable metabolite of TXA2) was concerned, at variance with reported data in young and old experimental animals. The addition to the cultures of exogenous AA caused a reorientation of cyclic endoperoxide metabolism resulting in a consistent decrease of the ratio TXB2/PGE2, but only in monocytes from young subjects. The data are discussed with respect to the claimed role of prostaglandins in the age-related immune derangement which is present in aged humans.

Adult↗
PubMed1986

[A method of venous study by real time ultrasonography associated with directional and continuous Doppler ultrasonography].

The authors propose a method of investigation of the superficial and deep venous axes of the limbs, neck, abdomen and pelvis by using successively directional and continuous wave Doppler and real time high resolution echotomography. The principle is to recognise normal and pathological venous flow by the Doppler technique and to detect the intrinsic (thrombus, agenesis) or extrinsic abnormalities causing local haemodynamic disturbances or distal emboli even in the absence of flow disturbance by echotomography. If the suggested protocol is strictly observed, the method allows diagnosis of the majority of pathologies, not only their haemodynamic consequences but also the underlying causes.

Hemodynamics↗
PubMed1985

[Popliteal artery entrapment. Contribution of ultrasonography].

Ultrasounds contribute significantly to the diagnosis of popliteal artery entrapment. The haemodynamic data obtained by Doppler's velocimetry and the parietal and morphological data obtained by ultrasonography make it possible to proceed beyond a diagnosis of "presumption" based on clinical and arteriographic findings and to reach directly a positive diagnosis of entrapment, even in cases with arterial obstruction. Between December, 1979 and December, 1983, 12 cases of popliteal artery entrapment (5 of type I, 1 of type II and 6 of type III) were diagnosed by ultrasonic methods in 8 patients. In each of these patients the data thus obtained concerning the diagnosis, the type of lesion and the arterial complications were fully confirmed by a subsequent arteriography and at surgery.

Adult↗
PubMed1985

Antibody response in partridge (Perdix perdix L.) 1. Effect of sex and age on the immune response to sheep red blood cells (SRBC), Newcastle disease virus (NDV) and Brucella abortus (Buck 19).

To ascertain the immune response capacity of Partridges to classical experimental and natural antigens, dose and time response curves to sheep red blood cells (SRBC), Newcastle disease virus (NDV) and Brucella abortus (Buck 19 strain), were determined in two strains reared in two different farms. 1 ml of 20% SRBC, 10(9) NDV particles and 10(7) Buck 19 microorganisms, gave optimal antibody responses seven (SRBC and Buck 19) or fourteen days after immunization. As far as SRBC is concerned, the antibody response was sex independent, but declined markedly in partridges older than 1 year. The immunization schedule used by us allow the identification of high and low responder animals. In fact, highly significant correlation in individual partridges between antibody titers obtained after two successive immunizations to an optimal SRBC dose given three weeks apart, was found. This fact, together with the observed great variability in the antibody response to the three antigens considered, should allow a selection for high and low responder lines, in order to improve the fitness toward environmental pathogens.

Age Factors↗
PubMed1985

Prostaglandin and thromboxane biosynthesis in isolated platelet-free human monocytes. I. A modified procedure for the characterization of the prostaglandin spectrum produced by resting and activated monocytes.

We have developed a technique to isolate monocytes from human peripheral blood. The technique takes special care of completely eliminating platelets which are usually present in other preparations. Monocytes obtained in good yields (2.5-5.0 X 10(5) cells/ml blood), were found to be 70-80% pure on the basis of morphological and histochemical criteria. Contamination was largely due to the presence of lymphocytes. Monocytes were incubated in the presence or absence of arachidonic acid and TXB2, PGE2 and 6-keto-PGF1 alpha were measured by specific and sensitive radio-immunoassays. It was found that when cells were incubated for up to 1 hr, the production of PGs was low or absent even in the presence of 10 microM arachidonic acid in the incubation medium. However, when incubations were carried out for 24 hrs in the presence of at least 1% fetal calf serum a dramatic increase in TXB2 production occurred, with levels as high as 150 ng X 10(6) cells. The ratio TXB2/PGE2 was around 3, while 6-keto-PGF1 alpha was produced at a much lower level. In the same conditions, when care was taken to evaluate PGs already present in fetal serum and/or cross reactivity due to media generally employed, purified human lymphocytes appeared unable to produce detectable levels of the three PGs tested.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Inhibition of cell proliferation by D-ribose and deoxy-D-ribose.

D-Ribose and deoxy-D-ribose inhibited DNA, RNA, and protein synthesis in a wide variety of cells (dividing and nondividing, normal and neoplastic, freely floating and substrate adhering, human and murine) at concentrations at which other monosaccharides have little or no effect. Inhibition was irreversible and proportional to the sugar concentration and time of contact. However, the first effects were seen only after 24 hr of incubation and progressed slowly to cell death. Whether the two sugars share the same mechanisms of action is not known. In any case, they deeply disturb metabolic processes in both dividing and nondividing cells.

Animals↗
PubMed1985

[Is it useful to correct the immunological deficit in cancer patients? And with what modality?].

A certain degree of immunodepression appears to be present in some neoplastic patients. Many factors such as age and nutritional and hormonal state (particularly thymic factors and locally-acting hormones like prostaglandins of E series) are involved in this phenomenon. The literature shows that all these factors are very important in neoplastic processes and might strikingly contribute also to the extent of immunodepression observed in neoplastic patients. Moreover, the HLA genotype seems to effect the efficiency of the antineoplastic treatments. The authors think that immunodepression in neoplastic patients might be improved by immunomodulators such as zinc ions, thymic hormones and, possibly, inhibitors of prostaglandins of E series.

HLA Antigens↗
PubMed1984

Thymic hormone deficiency in normal ageing and Down's syndrome: is there a primary failure of the thymus?

Normal individuals aged over 50 and most young Down's syndrome (DS) subjects had markedly reduced concentrations of circulating thymic hormone (facteur thymique sérique, FTS). Plasma from these two groups contained factors capable of inhibiting biological activity of FTS in vitro. Addition of zinc sulphate to plasma samples from DS subjects or the older individuals induced concentrations of FTS comparable to those observed in young healthy people and completely prevented FTS-inhibitory activity. These findings suggest that biologically active circulating thymic hormone is bound to zinc. The decline in thymic hormone activity in older individuals and DS subjects may be the result of changes in the mechanism of zinc-dependent activation of FTS molecules, which are probably associated with marginal zinc deficiency rather than with a primary failure of the thymus. Addition of zinc salt to plasma samples unmasks the presence of inactive FTS molecules.

Adolescent↗
PubMed1984

Megakaryocytopoiesis in bone marrow-derived stromal-hemopoietic cells co-cultures: action of Tamm-Horsfall glycoprotein.

Murine bone marrow cells are cultured in agar in the presence of marrow-derived fibroblasts and pokeweed-stimulated spleen conditioned medium. Granulo-monocytic colonies and a few megakaryocytic and mixed colonies are induced. The addition of Tamm-Horsfall glycoprotein - a human glycoprotein produced in the kidneys - increases the number of colonies and stimulates megakaryocytopoiesis. The glycoprotein does not have colony-stimulating activity nor does it induce megakaryocytopoiesis in monolayer cultures. Its major glycopeptide retains the ability to increase the number of colonies, but not to induce megakaryocytopoiesis. Cell-cell interactions occurring in the hemopoietic microenvironment and the effect of glucides are discussed.

Acetylcholinesterase↗
PubMed1984

Alterations of the capping phenomenon on lymphocytes from aged and Down's syndrome subjects.

The redistribution with the time of concanavalin A (Con A) receptors at one pole of the cell after addition of FITC-Con A - so-called capping - in the peripheral blood lymphocytes from 13 aged subjects (mean: 84 +/- 1 years old), and of 16 noninstitutionalized patients affected by a syndrome of precocious aging, such as Down's syndrome (mean: 17 +/- 2 years old), was studied and compared with a group of 15 normal young people (mean: 23 +/- 2 years old). An opposite alteration in the percentage of capped cells, i.e. a decrease in aged subjects and an increase in Down's syndrome patients, was observed. A derangement of lymphocyte membrane fluidity appears to be present in both groups even if the underlying biochemical defect may be different. However, a similar alteration of the kinetics of the phenomenon was present either in aged or in Down's syndrome subjects. Both groups did not show any significant increase with time of the percentage of capped cells, suggesting that they were lacking a lymphocyte subpopulation(s) which start capping later.

Adolescent↗
PubMed1984

[Ultrasonic diagnosis of aneurysmal polydystrophies].

Two methods are available for establishing a positive diagnosis of aneurysmal polydystrophies: the use of hemodynamic data from Doppler recordings to obtain details of the degree of parietal elasticity and the effect of parietal lesions on circulatory rate, and the application of real time ultrasound imaging to visualize the structure of the wall, the contents of the lumen and the level and extent of variations in caliber.

Aneurysm↗
PubMed1983

Purification and properties of two lectins from the latex of the euphorbiaceous plants Hura crepitans L. (sand-box tree) and Euphorbia characias L. (Mediterranean spurge).

1. From the latex of two members of the plant family Euphorbiaceae, Hura crepitans L. (sand-box tree) and Euphorbia characias L. (Mediterranean spurge), two lectins were purified by affinity chromatography on acid-treated Sepharose 6B followed by elution with D-galactose. 2. The lectin from E. characias is a single molecular species with Mr 80 000, made up of two identical subunits with Mr 40 000, and is a glycoprotein containing 11% carbohydrate. 3. The lectin from H. creptians appears as a mixture of three isolectins with Mr 140 000, consisting of four different subunits with Mr values 37 500, 35 500, 31 000, and 29 000. 4. Both lectins have haemagglutinating activity, with no specificity for human blood groups. The haemagglutinating activity is inhibited by D-galactose and by galactose-containing oligosaccharides. 5. The lectin from H. crepitans is mitogenic to human T-, but not to B-, lymphocytes. The latex of E. characias is mitogenic to T- and, to a lesser extent, to B-, lymphocytes, but the purified E. characias lectin has no mitogenic activity. 6. The lectin from H. crepitans, but not that from E. characias, inhibits protein synthesis by a rabbit reticulocyte lysate.

Amino Acids↗
PubMed1983

A microELISA assay to detect anti-liver-specific protein antibodies in the sera of patients with liver diseases.

A microELISA to detect anti-liver-specific protein (LSP) antibodies in human sera is described. Rabbit LSP was used as antigen. Optimal conditions for antigen concentration, serum dilution, substrate incubation time and reproducibility with time were established. The microELISA is specific, as assessed by testing anti-LSP positive sera with another lipoprotein from rabbit plasma (VLDL), although a weak cross-reactivity between LSP and VLDL was observed. The test was applied to patients with HBsAg-positive and -negative chronic active hepatitis (CAH). Ten of 26 (38%) patients were positive for anti-LSP antibodies, in comparison with healthy controls used to determine the threshold of positivity. Such a percentage is comparable with that reported for radioimmunoassay (RIA) procedures.

Antibody Specificity↗
PubMed1983

Enhancing effect of lithium and potassium ions on lectin-induced lymphocyte proliferation in aging and Down's syndrome subjects.

The effect of different concentrations of LiCl or KCl (0.6-20 meq/liter) on PHA-stimulated lymphocytes from young, old, and Down's syndrome subjects was studied. LiCl showed a dramatic enhancing effect on [3H]thymidine incorporation induced by a suboptimal dose of PHA in old subjects and Down's syndrome patients. An increase of [3H]thymidine incorporation in human lymphocytes stimulated by a suboptimal dose of PHA was also observed with KCl. This effect was higher in old subjects than that observed in young and Down's subjects. LiCl and KCl can modulate and partially restore the derangement in early events of mitogen stimulation which seems to be present in lymphocytes from both old and Down's syndrome subjects.

Adolescent↗
PubMed1983

Defective self-recognition in subjects of far-advanced age.

The immunocompetence of 22 subjects aged 85-104 years (mean 90 +/- 1 years) was studied and compared to 21 young subjects aged 19-37 years (mean 30 +/- 1 years). The absolute lymphocyte number and the percentage of T and B lymphocytes in the peripheral blood was similar in the two groups. A marked decrease in phytohemagglutinin response of T-enriched lymphocytes from old subjects was observed. Autologous mixed lymphocyte reaction (MLR) was also profoundly reduced in old subjects. No difference between male and female subjects was observed. The responsiveness of enriched T lymphocytes to allogeneic irradiated non-T cells was only slightly impaired in the old individuals. Non-T cells from old and young subjects functioned equally well as stimulatory cells in allogeneic MLR. The data suggest that an alteration of T lymphocytes with regulatory function and of self-recognition is present in aged humans.

Aged↗
PubMed1982

DNA repair after gamma radiation and superoxide dismutase activity in lymphocytes from subjects of far advanced age.

DNA repair after gamma radiation was studied in purified T lymphocytes from young and aged subjects. Two different assays were employed. In the first, T lymphocytes were stimulated with phytohemagglutinin (PHA) for 72 h and then treated with hydroxyurea, irradiated with 30 K rads and pulsed with [3H]thymidine (TdR) for 4 h. In the second, T lymphocytes were first irradiated with graded doses of gamma rays (200-800 rads) and then stimulated with PHA, cultured for 72 h and pulsed with 3H-TdR for the last 6 h of culture. T lymphocytes from aged subjects showed a lack of DNA repair synthesis in the first assay whereas only minor differences were found in the second assay between the two groups, i.e., a certain degree of radioresistance in aged lymphocytes. Lymphocyte superoxide dismutase activity showed great individual variations in both groups and a slight increase in old subjects.

Adolescent↗