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Biomedical subjects

F Di Padova

Publications and source records attributed to F Di Padova.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effect of cicloxilic acid on bile flow and biliary lipid secretion in humans.

Previous investigations have shown that cicloxilic acid, a hydrocholeretic drug, lowers bile cholesterol saturation without interfering with the intestinal absorption of cholesterol as well as with the hepatic synthesis of both cholesterol and bile acids. The mechanism whereby cicloxilic acid antagonizes lithogenic bile secretion is still unknown. However, most evidence favors the view of a relationship between choleretic and antilithogenic effects of the drug. To test this hypothesis the effects of a single oral dose (240 mg) of cicloxilic acid on bile flow and biliary lipid excretion rates have been examined in four nonobese cholecystectomized patients with balloon-occludable, reinfusion T-tubes. The results indicate that cicloxilic acid exerts a marked choleretic effect combined with a reduced output of bile cholesterol and an increase in bile acid excretion. Bile cholesterol saturation significantly decreases 90 min after cicloxilic acid in respect to control value. These data provide evidence of a link between choleretic and antilithogenic effects of cicloxilic acid and suggest its usefulness in the treatment of bile cholesterol supersaturation.

Adult↗
PubMed1983

Role of spleen in immune response to polyvalent pneumococcal vaccine.

The immune response of lymphocytes to subcutaneously administered pneumococcal vaccine was studied in five patients without spleens and in five healthy subjects. Seven days after immunisation circulating B cells synthesising IgG antipneumococcal capsular polysaccharides (anti-PCP) appeared in both groups. Twenty one days after vaccination this B cell population had disappeared and a B cell subset which secreted IgM and IgG anti-PCP in the presence of pokeweed mitogen was detected in the normal but not in the splenectomised subjects. In the splenectomised group polyclonal IgM synthesis induced by pokeweed mitogen was defective. It was concluded that the early events of the immune response to PCP may be mediated by lymph nodes but that, later, the spleen acquires a central role in producing lymphocyte subsets capable of synthesising specific antibodies and that this might explain the increased sensitivity of splenectomised subjects to pneumococcal infection.

Adult↗
PubMed1982

Effect of ethanol on biliary unconjugated bilirubin and its implication in pigment gallstone pathogenesis in humans.

Though some epidemiological investigations support the association between pigment gallstone formation and chronic alcoholism with cirrhosis, little attention has been paid to the influence of alcohol itself on biliary bilirubin secretion, so that the pathogenesis of pigment cholelithiasis in alcoholics is hitherto unknown. On different days we intravenously administered ethanol (0.7 g/kg body weight), diluted with 500 ml of saline, or saline alone to 6 non-obese patients with an indwelling T tube and reestablished enterohepatic bile circulation. At the time of the investigation bile cultures were negative for aerobic and anaerobic bacteria. Ethanol significantly increased biliary unconjugated bilirubin in respect to control values. The phenomenon reached a maximum 2 h after alcohol infusion when the value of unconjugated bilirubin averaged 2.37 +/- 0.30% of total bilirubin in contrast to 0.65 +/- 0.14% in control conditions (p less than 0.01), and subsided 6 h after the end of ethanol infusion. Since increased amounts of biliary unconjugated bilirubin predispose to pigment stone formation, it can be speculated that alcohol contributes to pigment cholelithiasis pathogenesis by enhancing the biliary concentrations of this form of pigment.

Adult↗
PubMed1982

Persistent immunologic abnormalities in long term survivors of kidney transplantation: role of different immunosuppressive treatments.

Although immunosuppressive treatment with corticosteroids and azathioprine has become a widely employed and highly effective mode of therapy in a variety of conditions, its influence on cellular and humoral immunity is still somewhat intriguing and controversial. In order to further investigate the status of the immune system during various maintenance immunosuppressive treatments, we have studied a group of 32 long term survivors of kidney transplantation who were treated with different immunosuppressive regimens. The present investigation demonstrates the presence of a persistent defect of T and B peripheral lymphocytes in long term kidney transplant recipients. Moreover, it shows that the immune deficits are influenced by the time-dose schedule of the maintenance immunosuppressive therapy but not by the duration of the treatment. In particular methylprednisolone in a daily dose schedule (8 mg per day as a single oral dose in the morning) with or without azathioprine (1.5-3 mg/kg per day as a single oral dose in the morning) produces a global defect of T and B cell populations, while the same dosage of methylprednisolone administered every other day (16 mg every other day as a single oral dose in the morning) in association with daily doses of azathioprine exerts a sparing effect on T cell populations. The humoral parameters do not show definite abnormalities. The factors that may have contributed to the genesis of the immune imbalances we have detected are discussed.

Adolescent↗
PubMed1982

Different survival of long-term kidney transplant recipients treated with daily or alternate day corticosteroids.

To define the effect of different immunosuppressive treatments on survival of long-term kidney transplant recipients, we have followed, for a period of four years, a group of 18 long-term survivors (more than three years) of kidney transplantation who were subjected to two different corticosteroid regimens (daily or alternate day corticosteroids) plus azathioprine. THis study not only confirms that an alternate day corticosteroid treatment reduces the incidence of infectious episodes and of side effects, but also suggests that it may steadily improve the survival of these patients. One of the six patients who performed an alternate day corticosteroid regimen died and only one lost renal graft function. On the contrary, three of the twelve patients who received daily corticosteroids died of causes related to immunosuppressive treatment, while another five patients lost renal graft function. A very low level of peripheral blood lymphocytes, of early E rosette and E rosette-forming cells was detected in patients who died of causes related to immunosuppressive treatment.

Adrenal Cortex Hormones↗
PubMed1981

Acute ethanol administration increases biliary concentrations of total and unconjugated bilirubin in rabbits.

Epidemiological investigations have revealed that alcoholic cirrhosis is associated with a high frequency of pigment gallstones, but only scanty information is available on the effects of ethanol on biliary secretion of bilirubin. We have injected intravenously 1.0 and 1.5 g/kg body wt of ethanol into six cholecystectomized rabbits and a common bile duct fistula. Experiments were performed ten days after surgery and a stream-splitting apparatus was interposed in the circuit in order to withdraw continuously biliary samples without interruption of enterohepatic bile circulation. Analysis of hourly data showed that both ethanol doses significantly increase the biliary concentration of total bilirubin, without affecting bile flow and lipid composition. Alcohol also promoted the efflux of unconjugated bilirubin into bile. The maximum effect occurred within the first 5 hr following alcohol administration. Thereafter the bile returned to normal. Since excessive concentrations of biliary unconjugated bilirubin favor pigment gallstone development, it can be speculated that alcohol acts as a risk factor for pigment lithiasis by enhancing the biliary levels of this form of pigment.

Animals↗
PubMed1980

Bile acid-induced inhibition of the lymphoproliferative response to phytohemagglutinin and pokeweed mitogen: an in vitro study.

The effects of free and conjugated bile acids on the lymphoproliferative response to phytohemagglutinin (PHA) or pokeweed mitogen (PWM) have been investigated in vitro. Significant inhibition of lymphocyte transformation was observed with 250 mumol/liter of either chenodeoxycholic (CDCA) or cholic acid (CA); the former caused more pronounced inhibition at higher concentrations. This was true whichever mitogen was present. Conjugated bile acids caused lesser degrees of inhibition than the respective free bile acids and the glycoconjugates were more inhibitory than the respective tauroconjugates of the same bile acid. At concentrations of free bile acids which completely suppressed lymphocyte transformation, no cytotoxic effects or impairment of cell viability were detected. Since the concentrations that inhibited the lymphoproliferative response were markedly lower than those reported to induce cell membrane damage, the activity observed can be attributed to a metabolic effect within the cell. Inhibition by bile acids of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity, resulting in a reduction of the endogenous cholesterol synthesis required for cell growth and proliferation, might account for our observations. Our results contribute to understanding the nature of the serum-dependent inhibition of lymphocyte transformation reported to exist in cholestatic liver disease.

Adult↗
PubMed1979

[A new approach to immunotherapy: the transfer factor].

The transfer factor is a tiny molecule capable of transferring the function of the T lymphocytes (immunological memory and retarded hypersensitivity) from a sensitized to a non-sensitized individual. The exact structure and action modalities of the molecule have not yet been precisely established. The difficulties involved in the study of the transfer factor are aggravated by the lack of any suitable experimental model. The attention of immunologists is attracted by this factor which opens up new prospects for the treatment of cancer, immunological deficiencies and certain infectious and autoimmune diseases. More profound research would appear useful to evaluate if and in what cases a potentiation of the immune mechanism can represent an alternative to immunosuppression.

Arthritis, Rheumatoid↗
PubMed1979

[Some parameters of cellular immunity in renal transplantation after more than three years].

This paper evaluates the cellular immune system of 16 cadaver kidney transplant recipients more than three years after transplantation. The number and percent of active E rosette forming cells, of E rosette forming cells and of IgG and IgM bearing lymphocytes were determined; the blastogenic response of peripheral blood lymphocytes to PHA and PWM was studied in homologous and autologous serum. Significant alterations of the tests performed were found in patients who had undergone kidney transplant, suggesting a pathogenetic role of chronic immunosuppressive therapy but not excluding other possible factors.

Adolescent↗
PubMed1978

[Behavior of some parameters of humoral immunity in renal transplants after more than 3 years].

This paper evaluates the humoral immune response of 15 cadaver kidney transplant recipients more than three years after transplantation. The study was performed by determining immunoglobulin levels, complement fractions and circulating antigen-antibody complexes. The data obtained suggest that humoral immunity is impaired in patients who have undergone kidney transplant, even after more than three years later. The impairment of immunocompetence may be ascribed both to the immunosuppressive therapy (corticosteroids and azathioprine) and to the transplanted organ itself which represents a chronic antigenic stimulus.

Adolescent↗
PubMed1977

Stimulation of lymphocytes by cholinergic receptor in myasthenia gravis.

Lymphocytes from 13 myasthenic patients were incubated in vitro with membranes enriched in nicotinic cholinergic receptor obtained from Torpedo marmorata electric organ. When autologous serum was present in the incubation medium, the lymphocytes were highly stimulated. In contrast, no stimulation occurred when lymphocytes were cultured in presence of AB serum. These results suggest that an immune response against the Ach cholinergic receptor is present in myasthenic patients and give further support to the hypothesis that an autoimmune response against muscular receptors may be involved in Myasthenia Gravis pathogenesis.

Adult↗
PubMed1976

[Pharmacological alteration of the antigenic properties of experimental leukemias detected by lymphocyte transformation].

It has previously been demonstrated that an in vitro antineoplastic treatment may induce new antigenic specificities in murine lymphomas. L1210 leukemia has been altered by DIC (L1210/DIC); drug-treated L1210 subline has been rejected by syngeneic animals. Here spleen cells from mice, normal or immune to L1210/DIC, have been stimulated in vitro by the L1210/DIC cells as measured by 3-h-thymidine uptake. Spleen cell stimulation did not occur with other syngeneic tumor cells and, as expected, spleen cells have been triggered by allogeneic cells. DIC-induced antigens stimulating syngeneic lymphocytes, as allogeneic cells did, have been demonstrated on L1210/DIC cells.

Animals↗
PubMed1976

Immunologic cross-reactivity of antigen(s) induced by drug treatment in two leukemic sublines.

Previous studies have demonstrated that new antigenic specificities, not detectable on parental cells, can be induced by in vivo treatment of murine leukemic cells with anti-neoplastic agents. The immunologic properties of leukemic cells altered by treatment with 5-(3,3-dimethyl-1-triazeno) imidazole-4-carboxamide (DIC) were investigated further. Immunologic cross-reactivity between two DIC-treated leukemic sublines has been demonstrated by cell-mediated immunity in vitro and by active or adoptive immunity in vivo. Rabbit antiserum to DIC-treated sublines absorbed with the parental cells showed residual activity against the DIC-sublines that was specifically inhibited by further absorption with DIC-cells.

Animals↗
PubMed1975

[Effect of cyclic nucleotides on the transformation and proliferation of lymphocytes].

When the studies on the immunologic system have met with the "second messenger" hypothesis of the cyclic nucleotides, new ideas have arisen about mechanisms regulating the immunologic reactions. Several works sustain a specific action of cyclic AMP and cyclic GMP to modulate the immunologic system, but the more subtle actions must be discovered. A hypothesis which attributes the control-task of the cellular functions to the c-AMP/c-GMP relation is presented.

Cell Division↗