Biomedical subjects

C Rugarli

Publications and source records attributed to C Rugarli.

At least 73 records · Page 4Linked to original sources

PubMed1987

Production of monoclonal antibodies specific to theophylline-treated lymphocytes.

The T11 molecule is reported to play a key role in T lymphocytes activation. Moreover, theophylline is known to modify the functional properties of T lymphocytes probably inducing early changes in T11 molecule during T cell activation. Aim of our work was to clarify the effect on T lymphocyte surface after in vitro treatment with theophylline. In this paper, we describe the production and the functional properties of several monoclonal antibodies obtained by immunizing Balb/c mice with theophylline treated cells. Some of the monoclonal antibodies reacted only with the theophylline-treated lymphocytes and showed a promitogenic activity, enhancing the expression of T activated cell antigen. These monoclonal antibodies seem to demonstrate the existence of a membrane molecule which appears on lymphocytes surface after a trigger signal occurring in the early stages of T cell activation likely related to the T11 dependent alternative pathway.

Animals↗

PubMed1987

Effect of cyclosporin A on 2ry MLR in patients with progressive systemic sclerosis.

We have studied the effects of the immunosuppressive agent Cyclosporin A (CsA) on the allogenic stimulation of human lymphocytes from 10 patients with progressive systemic sclerosis (PSS) and 10 healthy controls, when activated in vitro during 1ry and 2ry MLR. CsA markedly suppressed 1ry MLR in both PSS subjects and controls. In contrast to the marked suppression of 2ry MLR observed for most of the PSS subjects and all control subjects, lymphocytes from 3 out of 10 PSS patients had paradoxically amplified allogenic responses when primed in the presence of CsA. The possibility is discussed that in these patients the recruitment of suppressor-effector cells by CsA-resistant suppressor-inducer lymphocytes is impaired.

Adult↗

PubMed1987

Thymopentine treatment improves clinical and immunological functions in aged subjects with chronic bronchitis.

The effect of in vivo thymopentine treatment (50 mg/subcutaneously every other day for six weeks) on clinical features and in vitro immunological parameters was evaluated in ten aged patients with chronic bronchitis. In vitro immunological studies were performed before and after treatment both on phenotypic (OK monoclonal defined lymphocyte subpopulations) and functional parameters (blastogenic responses to polyclonal mitogens Concanavalin-A and Phytoemagglutinine). Thymopentine did not significantly affect lymphocyte subpopulations, which were reduced before pharmacological treatment, when compared to those of young healthy controls. Peripheral blood lymphocytes blastogenic response to polyclonal mitogens was restored, even though proliferation did not reach the values of young healthy subjects. Thymopentine treatment significantly improved lymphocyte functions, without being able, however, to overcome completely the age-dependent loss of blastogenic responses. Nevertheless the favourable evolution of clinical symptoms we observed in our study may be, at least in part, related to the improvement in vivo of those immunological functions that we studied in vitro. Eight out of ten patients showed an evident improvement of symptoms and signs of chronic bronchitis after thymopentine treatment and four of them arrived to a complete remission from infectious episodes. No side effects were noted. Although still preliminary, these results seem to be encouraging as thymopentine could be used with success as an immunomodulating agent in aged people.

Adjuvants, Immunologic↗

PubMed1987

Evidence for adenosine adenosinedeaminase lymphocyte system impairment in ageing.

Age related immune disfunctions are the result of humoral and cellular changes of the immune system and reflect major alterations of T cell subpopulations which concern cyclic nucleotides and their precursors. There are now many reports showing that adenosine can affect some phenotypic and functional lymphocyte characteristics. We have found that a short preincubation (30') with adenosine can inhibit proliferative responses of peripheral blood lymphocytes to polyclonal mitogen Concanavalin A in young healthy controls (p less than 0.05) but not in aged healthy subjects. These data led us to the hypothesis that an impairment of the adenosine-adenosinedeaminase system could play an important role in the age-associated decline of immune responses. Our results show a highly significant reduction (16.45 +/- 3.56 vs 24.42 +/- 9.5 p less than 0.001) of adenosinedeaminase activity in peripheral lymphocytes of aged humans (mean age 75.5 +/- 6.7 range 23-30). Preliminary studies suggest that this alteration could be responsible to some extent, for the decreased mitogenic response of lymphocytes reported in ageing.

Adenosine↗

PubMed1986

Adenosine induced production of a soluble factor affecting lymphocyte activation.

We show that a brief exposure of human peripheral blood mononuclear cells (PBMC) to adenosine or to theophylline results in a mitomycin C resistant regulatory activity. Adenosine induced suppression is also detectable in a lymphocyte subpopulation (T4+ enriched, originally described as helper inducer) resistant to the theophylline induced loss of capacity to form spontaneous rosettes with sheep erythrocytes (TTR). This activity is apparently dependent on the production of a soluble factor(s) since supernatants from adenosine treated TTR (SnA) exert a significant inhibition on the proliferative response of resting lymphocytes. On the contrary SnA increases the concanavalin A (ConA) preactivated lymphocytes proliferation. Similar results are detectable on the proliferative response in the mixed lymphocyte reaction (MLR). Perhaps these effects are related to different Interleukin 2 (Il 2) receptor expression on the cell surface of the resting and preactivated populations. A slow moving band corresponding to a protein of Mr of 64,500 and isoelectric point 7.6 is present in SnA. Only a slight Il 2 activity is detectable either in SnA and in control supernatant (SnC). These findings suggest that SnA may be a dynamic regulator of the early stages of lymphocyte activation.

Adenosine↗

PubMed1986

Impairment of lymphocyte-suppressive system in recent-onset insulin-dependent diabetes mellitus. Correlation with metabolic control.

Impairment of suppressor-cell activity may be important in the pathogenesis and maintenance of insulin-dependent diabetes mellitus (IDDM). In 23 recent-onset IDDM patients, lymphocyte sensitivity in vitro to theophylline was tested both in basal conditions and after improvement of metabolic control. This pharmacologic agent is mainly effective on a lymphocytic subpopulation with phenotypic and functional suppressive features. Peripheral blood lymphocytes from IDDM patients showed a loss of theophylline sensitivity, identified as inhibition of both E-rosette formation and blastogenic response to polyclonal mitogens concanavalin A (ConA) and phytohemagglutinin (PHA). An inverse relationship was demonstrated between the theophylline-induced suppression of ConA blastogenic response and blood glucose and glycosylated hemoglobin levels (P less than .01). Metabolic control seemed to be important even in relation to lymphocyte subpopulation distribution. In IDDM patients we found a significant (P less than .05) reduction of OKT4+ lymphocytes that is correlated with blood glucose and glycosylated hemoglobin levels (P less than .01). The improvement of metabolic control led to recovery of theophylline sensitivity. We suggest a deficiency in a suppressive system that could be involved in IDDM onset and the possible role of metabolic control in the impairment of some immunologic functions reported with this pathologic condition.

Adolescent↗

PubMed1986

Acute effect of a single infusion of papaverine on human peripheral lymphocyte.

It has been reported that drugs which modulate the intracellular levels of 3' 5' cyclic adenosinemonophosphate (cAMP) interfere with the cellular function of the immune system. In this work, papaverine, a drug effective in elevating cAMP levels, was observed to increase the T4+/T8+ ratio in vivo. Furthermore, peripheral blood mononuclear cells (PBMC) from young healthy volunteers who received intravenous papaverine (3 mg/kg i.v. over 15 min) showed a decreased response in allogenic mixed lymphocyte reaction (MLR) but a normal behaviour in a polyclonal mitogen assay and in autologous MLR (AMLR). These findings suggest that papaverine administration could influence the immune system functions.

Adult↗

PubMed1986

In vitro effects of halothane on lymphocytes.

Many reports indicate that anaesthesia affects several immunological functions that decrease the immune response, but the mechanisms involved are still unknown. We investigated the in vitro effect of halothane on human lymphocyte metabolism and plasma membrane function by evaluating the intracellular concentration of 3',5'-cyclic adenosine-monophosphate (cAMP), phosphodiesterase enzyme activity, NAD+/NADH intralymphocytic ratios and the degree of antibody and lectine-induced 'capping' of surface markers. Our results demonstrated an impaired lymphocyte capping of surface immunoglobulins and concanavalin A receptors 60 min after exposure to halothane at the concentration of 1% in oxygen. This phenomenon was reversible after 24 h and it was unrelated to the presence of adherent cells during the culture. Furthermore, halothane was able to induce a persistent increase in cAMP intracellular concentrations, which was reversible within 48 h. This effect was not dependent on adherent cells or on phosphodiesterase enzyme inhibition. Finally, no alteration in NAD+/NADH ratios after halothane exposure was observed.

Cyclic AMP↗

PubMed1985

Effect of cyclosporine and aminophylline on streptozotocin-induced diabetes in rats.

Diabetes induced in rats by multiple low doses of streptozotocin is thought to mimic type 1 disease in man. We tested the effect of concomitant treatment with immunomodulator drugs in this diabetic experimental model. Administration of cyclosporine resulted in a rapid appearance of hyperglycemia, perhaps by a potentiation of the direct cytotoxic action of streptozotocin on beta cells. By contrast, aminophylline administration protected the animals from the diabetogenic action of streptozotocin. Concomitant treatment with aminophylline and cyclosporine failed to protect the rats from the hyperglycemia induced by streptozotocin.

Aminophylline↗

PubMed1985

Relation between enzymatic activities and the degree of malignancy of human lymphomas.

The relationship between the intracellular levels of DNA polymerase alpha (DP-alpha), adenosine deaminase (ADA) and lactate dehydrogenase (LDH) and the degree of malignancy of human lymphomas was investigated. Twelve non-neoplastic lymph nodes and 88 malignant lymphomas were examined. For non-Hodgkin's lymphomas (NHL) the low or high grade of malignancy was established according to three classifications: the Rappaport, the Kiel and the Working Formulation for Clinical Usage, with the latter also recognizing an intermediate grade group. Non-neoplastic lymph nodes had significantly lower levels of all the three enzymes than those found in high-grade malignant NHL (the P value ranged from less than 0.02 to less than 0.001). Hodgkin's disease, a slowly evolving neoplasia, showed lower levels of DP-alpha (P less than 0.001) and ADA (P less than 0.001), but not of LDH, than high-grade NHL. Among NHL, whatever classification was used, the low-grade malignant lymphomas had significantly lower levels than the high-grade ones for all the three enzymes (P less than 0.005 or P less than 0.001). The intermediate-grade group of the Working Formulation differed from the high-grade group for DP-alpha (P less than 0.01) and ADA (P less than 0.02) but not for LDH. It differed from the low-grade group only for ADA (P less than 0.005). Lymphoblastic and Burkitt's lymphomas were the groups with the highest levels of the three enzymes. Among low-grade lymphomas very low values were found in the histological entities defined as DLWD in the Rappaport classification, CLL and lymphoplasmacytoid immunocytoma in the Kiel classification and small lymphocytic (group A) in the WF. The levels of all enzymes in these histotypes were always significantly different from the other low-grade histotypes, and from the intermediate-grade ones of the WF. In the Kiel classification polymorphous lymphoplasmacytoid lymphoma, recently recognized as a group with a quite aggressive clinical course, was characterized by high levels of all three enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Deaminase↗

PubMed1985

Theophylline induced non specific suppressor activity in human peripheral blood lymphocytes.

It is wellknown that theophylline yields phenotypic changes on suppressor cells. In the present study we investigated the possibility that theophylline could directly induce a suppressor activity on a lymphocyte subpopulation. We observed that a short preincubation (120 min at 37 degrees C) with theophylline (1mM) activates human peripheral blood lymphocytes to suppress mitogenic response of autologous cells. This activity was not evident on a T cell subpopulation depleted of theophylline-sensitive (T-sens) lymphocytes. Theophylline mediated suppressor activity is only present in the Concanavalin A stimulated cultures, thus suggesting a synergism between Concanavalin A and theophylline in the expression of non specific suppression. Moreover we observed that after a 24 hrs preincubation of lymphocytes in complete culture medium there was a complete loss of theophylline-induced suppression. Such a preincubation time also produced a decrease in the theophylline-mediated enhancement of intracellular 3', 5' cyclic adenosine monophosphate levels and the impairment of E-rosette formation, suggesting that theophylline acts mainly on a "short-lived" suppressor lymphocyte subset.

Adult↗

PubMed1984

Lysosomal glycohydrolases in normal T and non-T peripheral lymphocytes.

The optimal assay conditions and the levels of seven lysosomal glycohydrolases (alpha-D-galactosidase, beta-D-galactosidase, beta-D-glucosidase, beta-D-glucuronidase, beta-N-acetyl-D-glucosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase), alpha-D-mannosidase, alpha-L-fucosidase) were determined in human peripheral unseparated lymphocytes, T and non-T lymphocyte subpopulations. From fifteen adult volunteers the enzymes were assayed by fluorimetric procedures using the corresponding 4-methylumbelliferyl glycosides as substrates. The enzyme assay procedures displayed good precision and reproducibility. All the tested enzymes had higher activities in non-T than T lymphocytes. This difference was statistically highly significant, especially when the enzyme contents were expressed on a DNA, rather than mg protein, basis. Unseparated lymphocytes displayed levels of lysosomal enzymes which corresponded to the proportion of T and non-T lymphocytes in the unseparated preparation, indicating that the process of lymphocyte fractionation caused neither loss nor activation of lysosomal enzymes. It is concluded that the observed difference in lysosomal enzyme levels is an authentic imprint of the two lymphocyte subpopulations, implying a differential role played by the lysosomal apparatus in the same cells.

Adult↗

PubMed1984

In vivo effects of a single infusion of theophylline on human peripheral blood lymphocytes.

It has recently been proposed that theophylline activates T suppressor systems in vivo and this evidence is further supported by the ability of the drug to attenuate the allograft rejection in humans and in experimental animals. In this study the acute effects of aminophylline on human peripheral blood lymphocyte (PBL) mitogenic responses have been investigated. PBL from healthy young volunteers who received intravenous aminophylline (5 mg/kg i.v. over 20 min) showed an increased proliferative response to phytohaemagglutinin. This was correlated with an augmented OKT4/OKT8 ratio, due to an absolute increase in the OKT4+ subset as well as a decrease in OKT8+ cells. Furthermore, following in vivo aminophylline we observed a significant rise in lymphocyte cAMP levels. These data, together with studies from other laboratories, suggest that the dosages and duration of treatment may influence greatly the theophylline-induced modulation of immune functions.

Adult↗

PubMed1984

Nucleotide metabolism in spleen and peripheral blood lymphocytes during theophylline treatment.

The in vivo effect of theophylline on lymphocyte nucleotide metabolism was investigated. Rat peripheral blood lymphocytes presented more elevated levels of adenosine 5'-triphosphate (ATP) and cyclic adenosine 3',5'-monophosphate (cAMP) than shown by spleen lymphocytes. A continuous (15 days) daily oral treatment of the rats with aminophylline increased intralymphocytic cAMp content in peripheral blood (by 14 times) and in spleen lymphocytes (by 4 times), whereas ATP content was not significantly changed. NAD+ and NADH levels and NAD+/NADH ratios appeared higher in peripheral blood than in spleen cells, and were not influenced by aminophylline treatment. These results may be explained by assuming the existence of a different distribution of lymphocyte subpopulations and of a different sensitivity of the same to aminophylline treatment. The studies of nucleotide variation in peripheral blood lymphocytes incubated at 37 degrees C in anoxic conditions (N2+CO2, 95:5) revealed an impairment of ATP production and a well-preserved redox state.

Adenosine Triphosphate↗

PubMed1983

Spontaneous "in vitro" variations of theophylline sensitivity in human peripheral blood lymphocytes.

Theophylline reversibly inhibits E rosette formation by a portion of human circulating T lymphocytes. We investigated the effect of theophylline on E rosette formation and intracellular content of cyclic nucleotides (cAMP, cGMP). When the amine is added to 15 human healthy donors' lymphocytes either before or after 24 hours of culture at 37 degrees C, in absence of mitogens, a portion of theophylline-sensitive T cells spontaneously becomes theophylline-resistant after 24 hours of culture. While the intracellular content of cAMP does not significantly vary, the ability of theophylline to induce an increase of cAMP appears to be impaired after 24 hours of culture. The possible correlation between theophylline resistance and impaired turnover of cAMP in the cultured lymphocytes is discussed.

Cyclic AMP↗

PubMed1983

Prolonged survival of experimental heart transplantation induced by theophylline.

High levels of cyclic adenosine monophosphate (cAMP) in lymphocytes are associated with a reduction in many immunological functions. Theophylline, a drug effective in elevating lymphocyte cAMP levels, was employed as a single immunomodulator treatment in rats submitted to heterotopic heart allotransplantation. In 3 strain combinations, the graft survival was consistently prolonged in treated animals in comparison with untreated controls.

Abdominal Neoplasms↗

PubMed1982

MLC-specific suppressor T lymphocytes in man. I. Their induction in vitro by soluble HLA-DR antigens.

Human T lymphocytes precultured for 36 hr in the presence of soluble HLA-DR antigens suppress the MLR response of autologous peripheral blood lymphocytes to allogeneic stimulating cells. The suppression is DR antigen-specific in that it appears that the MLR stimulating cell donor and the soluble suppressor-inducing antigen must share DR specificities. The soluble DR antigens were fractionated from the sera of normal donors using QAE-Sephadex chromatography and CNBr-activated Sepharose immunoadsorption. Similarly prepared HLA-A and -B antigens failed to induce suppressive activity. The suppressive activity of DR-antigen cultured T cells is resistant to mitomycin C treatment and, further, the antigen specificity is maintained with or without mitomycin C treatment. The kinetics of suppressor cell induction as well as the kinetics of suppression in the test MLR cultures are presented. The implications of these results are discussed.

Adult↗

PubMed1980

Increase of T.G lymphocytes in human one-way mixed lymphocyte culture.

Human one-way mixed lymphocyte culture induces a significant increase of EA(7S) rosette-forming cells. Using fractionation procedures, an increased number of Fc receptor-bearing cells in the T high-enriched populations was found from alloactivated lymphocytes compared with similar fractions obtained after autologous control cultures. Additional experiments showed a parallel increase of E-rosette-forming cells in the Fc receptor-enriched alloactivated fractions. The results indicate that an increase of T.G lymphocytes occurs during in vitro alloactivation in man.

Cell Count↗