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Biomedical subjects

R Giordani

Publications and source records attributed to R Giordani.

At least 55 records · Page 3Linked to original sources
PubMed1988

Potential role of interleukin-1 as the trigger for diffuse intravascular coagulation in acute nonlymphoblastic leukemia.

Abnormalities of coagulation are common in patients with acute nonlymphoblastic leukemia, although the mechanisms involved are unclear, except in a few cases. To investigate the pathogenesis of this coagulopathy, suspensions of purified leukemic cells were prepared and tested for procoagulant activity. Neither the leukemic cells nor their supernatants directly accelerated the clotting of plasma. Since the leukemic cells did not possess direct procoagulant activity, their ability or inability to elaborate a mediator of cellular coagulant properties, interleukin-1, was studied. Leukemic cells from patients with coagulopathy elaborated interleukin-1, and addition of phytohemagglutinin increased interleukin-1 release. In contrast, no interleukin-1 was released, before or after stimulation with phytohemagglutinin, from leukemic cells from patients without coagulopathy. Leukemic cells from another group of patients with abnormalities of coagulation released interleukin-1 only after phytohemagglutinin treatment. In terms of the coagulation mechanism, interleukin-1 containing supernatants from leukemic cell cultures induced the procoagulant receptor tissue factor, a co-factor in the initiation of coagulation, on the endothelial cell surface. There was coordinate suppression of the anticoagulant endothelial cell receptor thrombomodulin, a co-factor for the antithrombotic protein C pathway. Antibody to interleukin-1 prevented these changes in cellular coagulant properties. Taken together, these changes result in a shift in the balance of endothelial cell coagulant properties to an activated state in which mechanisms promoting procoagulant reactions on the vessel surface predominate. Synthesis and release of the mediator interleukin-1 by leukemic cells thus defines a new mechanism through which malignant cells can potentially activate the coagulation mechanism.

Acute Disease↗
PubMed1987

Characterization of cells from invaded lymph nodes in patients with solid tumors. Lymphokine requirement for tumor-specific lymphoproliferative response.

The specific immune response against the malignant cells was investigated in patients with urinary bladder or larynx cancer. Lymphocytes from lymph nodes that drain the tumor site were tested for their proliferative and cytotoxic capacities against autologous malignant cells isolated from the primary tumor. In no occasion was a proliferative or a cytotoxic response observed. However, when the lymph node cell suspensions were depleted of cells expressing both OKM1 and Leu-7 markers by rosetting with the appropriate mAbs, a proliferative response could be observed. The lymphocytes responded to autologous tumor cells only if IL-2 was added to the cultures. IL-2 alone induced some cell proliferation, which was not, however, comparable to that observed in response to both IL-2 and tumor cells. A panel of allogeneic tumor cells consistently failed to stimulate OKM1-, Leu-7- cells in vitro. Response to autologous tumor cells was not caused by HLA-encoded molecules, as occurs in the autologous mixed lymphocyte reaction, since OKM1-, Leu-7- cells failed to be stimulated by autologous non-T cells. A proliferative response was observed only with cells from lymph nodes that had been classified as invaded by malignant cells according to histopathologic criteria. Cells from noninvaded lymph nodes consistently failed to respond. Cells stimulated with autologous tumor cells could be expanded in short-term lines by continuous addition of IL-2 and malignant cells. One of these lines, which comprised mainly T8+ cells, was stimulated to proliferate only by autologous tumor cells, and its proliferative response was inhibitable by anti-class I and not by anti-class II mAbs. This line showed lytic capacities against autologous malignant targets, while it was inefficient against all of the other allogeneic cells tested. In another set of experiments, the mechanisms whereby exogenous IL-2 had to be added to the cultures to sustain a proliferative response against neoplastic cells were investigated. When cocultured with autologous malignant cells, OKM1-, Leu-7- lymphocytes expressed IL-2 receptors, as could be assessed by anti-Tac fluorescent staining. Under these culture conditions, these cells did not produce IL-2, and no proliferation was observed. Addition of purified IL-1 to the cultures induced IL-2 production and cell proliferation. It is concluded that metastatic lymph nodes contain a T cell population that can be detected in a proliferative assay when both suppressor cells are removed and the appropriate molecular signals are supplied.

Antigens, Surface↗
PubMed1987

Platelet aggregation behaviour in patients treated with ticlopidine.

Thirty patients (18 women, 12 men) with permanent or paroxysmal atrial fibrillation were treated with a new antiplatelet drug, ticlopidine, in order to study platelet aggregation behaviour, to see whether the drug prevents thromboembolisms and to observe side-effects over a period of 6 months. A further comparative study of the effects of ticlopidine and dipyridamole + aspirin on platelet aggregation was carried out in 20 patients. All appropriate haematological parameters were tested every 3 months, while platelet aggregation curves with ADP were examined also after 15 days. At the end of the period an echocardiogram was performed to check for any sign of thrombosis. The reduction in the aggregation curves was statistically significant for all the ADP stimuli, except at low doses. In the comparison with dipyridamole + aspirin, ticlopidine gave better results; with the former there was no significant reduction in platelet aggregation. A more significant reduction was seen in patients who had showed hyperaggregation at the outset. Bleeding time was increased and platelet adhesivity was reduced. During the 6-month period a slight reduction in white blood cells and a slight increase in creatinine were observed, both remaining within the normal range. Some 33.3% of the patients experienced side-effects. No embolic event or thrombosis in the left atrium was seen. Ticlopidine seems to be an effective antiplatelet drug, especially for patients with hyperaggregation.

Adult↗
PubMed1987

Azthreonam in the treatment of urinary tract infection: evaluation of efficacy, renal effects and nephrotoxicity.

The efficacy, renal effects and nephrotoxicity of a short course of treatment with azthreonam were evaluated in 11 adult patients with urinary tract infection. Azthreonam was administered for 5 days at a daily dose adjusted to the residual renal function of the patients. In the pre-treatment period, during treatment and 10 days after completion of therapy, urine cultures, urinalysis and routine renal function tests (clearance of creatinine, urea and uric acid) were performed and urinary enzymes (alanine-aminopeptidase, gamma-glutamyl-transpeptidase, N-acetyl-beta-D-glucosaminidase, lysozyme) were determined. Renal haemodynamics (glomerular filtration rate and effective renal plasma flow) were measured in the pretreatment period and on the 5th day of therapy. The results confirm the efficacy of azthreonam for treatment of urinary tract infection. Results of renal function tests and measurements of urinary enzymes remained unchanged during and after treatment with azthreonam. These data support the conclusion that azthreonam is an effective antimicrobial agent which does not influence renal function or cause nephrotoxic effects.

Adult↗
PubMed1986

Serum and urinary enzyme activities in renal artery embolism.

Renal artery embolism is not a rare occurrence, especially in patients with valvular heart disease, but the early diagnosis of this condition is infrequently accomplished. We report the clinical and laboratory data of 2 patients with valvular heart disease who presented with unilateral renal artery embolization. The usefulness of the determination of serum and urinary enzymes and renal function tests is discussed. We propose that these parameters support an earlier and more accurate diagnosis of renal artery embolism.

Acetylglucosaminidase↗
PubMed1986

Presence of activated T-cells with a T8+ M1+ Leu 7+ surface phenotype in invaded lymph nodes from patients with solid tumors.

The lymphocyte surface phenotype of lymph nodes from patients with larynx or urinary bladder carcinoma was investigated by using a panel of monoclonal antibodies. The phenotype pattern of lymphocytes from lymph nodes invaded by malignant cells (as assessed by histopathology) was different from that of the cells from noninvaded or normal control nodes. Although the proportion of natural killer cells or macrophages was similar in the 3 groups of lymph nodes, invaded lymph nodes contained a higher proportion of T-cells and a lower B-cell percentage. Furthermore, cells from invaded nodes comprised 15-20% of T3+ T8+ cells that coexpressed the M1 marker and, to some extent, also the Leu 7 marker. A large proportion of cells with multiple markers were activated, as shown by the expression of Tac and HLA-DR antigens. In 2 patients activated T8+ cells expressing also M1 and Leu 7 markers infiltrated the tumor site. The presence of these activated cells both in involved nodes and tumor mass may indicate that they originate in response to cancer.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1982

An investigation into the feasibility of using azide-insensitive ATPase and ConA as yeast plasma membrane markers.

Cytochemical localization of Concanavalin A binding sites in protoplasts of Candida tropicalis, investigated with glycosylated-ferritin and electron microscopy, showed that the lectin was specifically bound to the external protoplast surface. Thus, the plasma membranes have been labelled with 125I-Concanavalin A and followed through the isolation procedure. Relative distribution of 125I-radioactivity and azide-insensitive ATPase activity in the obtained fractions, suggested that this enzyme was an equivocal plasma membrane marker. Despite the presence of internal Concanavalin A binding sites, Concanavalin A could be used unambiguously as an exogenous plasma membrane marker of intact protoplasts.

Adenosine Triphosphatases↗
PubMed1981

Characterization of the plasma membrane ATPase of Candida tropicalis.

1) Plasma membrane vesicles from Candida tropicalis were isolated from protoplasts by differential centrifugation and purified in a continuous sucrose gradient. 2) The plasma membrane bound ATPase was characterized. It is highly specific for ATP and requires Mg2+. It is stimulated by K+, Na+ and NH4+. Lineweaver-Burk plots for ATPase activity are linear with a Vmax of 4.2 mumoles of ATP hydrolyzed min-1.mg-1 protein and a Km for ATP of 0.76 mM. The ATPase activity is inhibited competitively by ADP with a Ki of 1.7 mM and non competitively by vanadate with a Ki of 3 microM. The activity is unaffected by oligomycin or azide but is sensitive to DCCD.

Adenosine Diphosphate↗
PubMedDate not supplied

Influence of oxygen on the microsomal electron transport system in Saccharomyces cerevisiae.

The influence of oxygen on the level of microsomal electron transport chain components has been studied during the growth of Saccharomyces cerevisiae. Enzyme activities and cytochrome content were assayed in microsomal fractions prepared from a protoplast lysate free from mitochondrial contamination. It was found that the cytochrome P-450 and cytochrome b5 content, to get her with the NADPH-cytochrome (P-450)-reductase and NADH-cytochrome (b5)-reductase activities, were increased in the cells as the pO2 of the medium was decreasing. At the same time an increase in the membrane surface of the endoplasmic reticulum can be observed.

Cytochrome P-450 Enzyme System↗
PubMedDate not supplied

Serum gamma-glutamyl-transpeptidase isoforms in alcoholic liver disease.

gamma-Glutamyltranspeptidase (gamma GT) appears in serum in multiple forms; their significance and clinical utility in hepatobiliary and pancreatic diseases are still a matter of controversy. Electrophoretic separation of the multiple forms of gamma GT on agarose gel was performed in 20 alcoholic patients (six with cirrhosis and 14 with fatty liver) and the results compared with those obtained in 50 healthy volunteers, 43 patients affected with chronic hepatitis C, 36 patients with posthepatitic cirrhosis and in 52 epileptic patients on long-term anti-epileptic medication. Multiple forms of gamma GT were separated into several bands (up to 11), labelled 0a, 0b, 1a, 1b, 2a, 2b, 2c, 3a, 3b, 4a, 4b. In the alcoholic patients nine fractions were detected, and the electrophoretic pattern observed was significantly different from that observed in healthy volunteers and in patients with chronic hepatitis C or posthepatitic cirrhosis. No differences were observed in the electrophoretic patterns in the alcohol abusers and epileptic patients. In alcoholic patients significant differences were observed in the electrophoretic patterns in relation to the degree of liver injury; the electrophoretic patterns in patients with alcohol-related cirrhosis and posthepatitic cirrhosis differed significantly. The separation of multiple forms of gamma GT has high sensitivity and good reproducibility. It may be proposed as a complementary test in the diagnosis of alcoholic liver disease.

Adult↗
PubMedDate not supplied

Glycosidic activities of Candida albicans after action of vegetable latex saps (natural antifungals) and isoconazole (synthetic antifungal).

Glycosidic activities have been examined in Candida albicans grown on medium culture containing latex sap (natural antifungal) or isoconazole (synthetic antifungal). The different types of utilized latex sap were those of Lactuca sativa (latex exuded from articulated laticifers) and Asclepias curassavica (latex flowing from non-articulated laticifers). The same enzyme assays were performed on C. albicans grown without antifungal compounds. Except for alpha-arabinosidase, all glycosidase activities were increased when C. albicans was grown in medium supplemented with L. sativa latex sap. The most stimulated activities were those of beta-fucosidase, alpha-galactosidase, alpha- and beta-glucosidase, alpha- and beta-mannosidase, acetyl-beta-glucosaminidase. The presence of A. curassavica latex sap in culture medium produced similar results: the most stimulated activities were those of alpha-mannosidase, alpha-galactosidase, acetyl-beta-glucosaminidase and beta-fucosidase. Electron microscope observations suggested a correlation between this stimulation of glycosidic activities and the fungal cell wall breakdown. For comparison the presence of isoconazole in culture medium yields no increase in glycosidic activities and no ultrastructural modification of fungal cell wall. The mode of action of latex saps in cell wall breakdown is discussed.

Antifungal Agents↗
PubMedDate not supplied

Antifungal action of Carica papaya latex: isolation of fungal cell wall hydrolysing enzymes.

Carica papaya latex inhibits the growth of Candida albicans. Latex proteins appear to be responsible for this antifungal effect. The minimum protein concentration for producing a complete inhibition was estimated to be about 138 micrograms ml-1. Exploration of different glycosidic activities shows that only alpha-D-mannosidase and N-acetyl-beta-D-glucosaminidase were present in latex in important levels and they were partially purified. The two enzymes show a limited inhibitory effect on yeast growth, alpha-D-mannosidase being more efficient than N-acetyl-beta-D-glucosaminidase. A mixture of the two enzymes showed a synergistic action on the inhibition of the yeast growth. Scanning and transmission electron microscopy observations showed a lack of polysaccharidic content on outermost layers of yeast cell walls when alpha-D-mannosidase was added to the culture medium. When C. albicans was cultured in medium supplemented with N-acetyl-beta-D-glucosaminidase a lack of polysaccharides was noted not only in the outermost layers of fungal cell wall but also in the inner layers. The potential utilization of latex glycosidases in combination with antifungals such as polyenes and azoles involving the formation of protoplasts is discussed.

Acetylglucosaminidase↗
PubMedDate not supplied

Fungicidal activity of latex sap from Carica papaya and antifungal effect of D(+)-glucosamine on Candida albicans growth.

Carica papaya latex sap inhibits the growth of Candida albicans when added to a culture during the exponential growth phase. Approximately 60% was achieved. This fungistatic effect is the result of cell wall degradation due to a lack of polysaccharidic constituents in the outermost layers of the fungal cell wall and release of cell debris into the culture medium. When C. albicans was cultured on medium supplemented with D(+)-glucosamine, an inhibitor of N-acetyl-beta-D-glucosaminidase, growth was inhibited (34%) in a similar manner. Addition of D(+)-glucosamine during the exponential growth phase also had a fungistatic effect (26%). The modes of action of C. papaya latex and of D(+)-glucosamine in cell wall breakdown are discussed.

Acetylglucosaminidase↗