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Biomedical subjects

P Malec

Publications and source records attributed to P Malec.

17 recordsLinked to original sources
PubMed2001

Formaldehyde and methanol biodegradation with the methylotrophic yeast Hansenula polymorpha. An application to real wastewater treatment.

The application of methylotrophic yeast Hansenula polymorpha to the treatment of methanol and formaldehydecontaining wastewater was experimentally verified. A variety of real wastewater samples originating from chemical industry effluent were examined. The yeast cell culture could grow in the wastewater environment, revealing low trophic requirements and a very high adaptation potential to poor cultivation conditions. The proliferation of cells was accompanied by a concomitant xenobiotic biodegradation. Grown, preadapted cellular suspension at a density of about 1 x 10(7) cells/ml proved to be able to utilize formaldehyde present in wastewater at concentrations up to 1750 mg/l, levels toxic to most microorganisms. The biological waste treatment method presented shows the enhanced potential by means of specific enzymatic activities of monocarbonic compound oxidations through methylotrophic pathway reactions. The need to obtain mutants highly resistant to formaldehyde has also been rationalized.

Biodegradation, Environmental↗
PubMed1999

Arabidopsis FUSCA5 encodes a novel phosphoprotein that is a component of the COP9 complex.

The COP9 complex is a regulator essential for repression of light-mediated development in Arabidopsis. Using partial amino acid sequence data generated from purified COP9 complexes, we cloned the Arabidopsis cDNA encoding the 27-kD subunit of the COP9 complex and showed that it is encoded by the previously identified FUSCA5 (FUS5) locus. fus5 mutants exhibit constitutive photomorphogenic phenotypes similar to those of cop9 and fus6. Point mutations in FUS5 that led to a loss of FUS5 protein were detected in four fus5 allelic strains. FUS5 contains the PCI/PINT and mitogen-activated protein kinase kinase activation loop motifs and is highly conserved with the mammalian COP9 complex subunit 7 and the Aspergillus nidulans AcoB proteins. FUS5 is present in both complex and monomeric forms. In the COP9 complex, FUS5 may interact directly with FUS6 and COP9. Mutations in FUS6 and COP9 result in a shift in the electrophoretic mobility of FUS5. This shift can be mimicked by in vitro phosphorylation of FUS5 by plant extracts. These findings further support the hypothesis that the COP9 complex is a central and common regulator that may interact with multiple signaling pathways.

Amino Acid Sequence↗
PubMed1992

Mixed interleukins and thymosin fraction V synergistically induce T lymphocyte development in hydrocortisone-treated aged mice.

Analysis of the role of interleukins in T cell ontogeny in vitro indicates that the regulation of T cell development involves interleukins (ILs) as well as thymic hormones (THs). In order to assess their respective roles in T lymphocyte development in vivo, chemically thymectomized mice were treated with ILs and THs. After 2 days of hydrocortisone treatment, aged mice showed acute thymic involution (weight was less than 30% of control) and reduced spleen size (less than 80% of control) with progressive recovery to 8 days. After 2 days of hydrocortisone treatment, adult mice were injected for 5 days with mixed buffy coat interleukins (BC-IL; 50 units IL2 equivalence), purified IL2 (50 units), rIL1 beta (4 ng), and thymosin fraction V (TF5; 100 micrograms). The animals were sacrificed and spleens and thymuses were analyzed for weight, cellularity, T cell number, subsets, and function as determined by proliferative responses to concanavalin A and ILs. BC-IL treatment increased the recovery of spleen and thymus weights and cellularity with corresponding augmentation of number and function of T lymphocytes; neither IL1 or IL2 or their combination had this effect. TF5 had no effect alone but strongly potentiated the effect of BC-IL on T lymphocyte function. These data indicate that BC-IL in combination with thymic peptides potently promotes T lymphocyte development. The combination may be therapeutically relevant for immunorestoration.

Aging↗
PubMed1989

Immunomodulatory effect of naloxone in duodenal ulcer patients.

The effect of a single dose of the opiate receptor antagonist naloxone (NAL) on some immune parameters in chronic duodenal ulcer patients and healthy controls was investigated. Twelve hospitalized men, aged 19-23 years (nine duodenal ulcer patients and three controls) were given NAL intravenously at a dose of 0.03 mg/kg. Blood samples were drawn before and 30 and 150 min after NAL injection. Results obtained in duodenal ulcer patients and healthy subjects revealed the same direction of changes despite a rather wide scatter. Baseline NK cell activity was lower in duodenal ulcer patients than in healthy persons. In approximately one fourth of patients the changes in individual parameters observed following NAL injection were slight. Numbers of total lymphocytes, Th, Ts, NK cells, monocytes and Th/Ts ratio did not significantly change after NAL administration. T-lymphocyte counts moderately decreased at 30 min after NAL injection. NAL did not affect spontaneous IL-2 receptor expression and it moderately increased PHA-induced IL-2 receptor expression in most of the investigated persons. IL-2 generation and NK cell activity slightly, but significantly, increased at 30 min following NAL injection. NAL markedly inhibited lymphocyte proliferation in an AMLR test 30 min after its administration. Most of the investigated parameters returned to their initial levels after 150 min following NAL administration. The studies showed that not only endorphins and enkephalins may have an immunomodulatory action, but NAL, their antagonist, may also affect some functions of the immune system in humans, although its action is transient.

Adjuvants, Immunologic↗
PubMed1989

Effect of epinephrine, propranolol, and verapamil on the chemiluminescence of neutrophils in duodenal ulcer patients.

To answer the question whether beta-adrenergic receptor agonists or antagonists and calcium channel blocking agents affect activation of neutrophils in vivo, the chemiluminescence (CL) test was employed. The intensity of emitted photons was amplified by luminol. The effect of investigated agents was measured after stimulation of isolated peripheral blood polymorphonuclear leukocytes (PMNLs) with opsonized zymosan particles. The investigations were performed on 9 duodenal ulcer patients, aged 19-23 years, after informed consent. Single subcutaneous dose of epinephrine (0.014 mg/kg) induced a marked increase in PMNL number and a moderate, but significant, decrease in CL 30 min after injection. Verapamil (0.15 mg/kg intravenously) diminished CL, propranolol (0.1 mg/kg intravenously) enhanced CL, but 150 min after injections CL was approaching the initial values. The obtained results suggest that the investigated compounds may modify the PMNL function in vivo.

Adult↗
PubMed1988

Propranolol enhances in vitro interleukin 2 receptor expression on human lymphocytes.

Interleukin 2 receptor (IL-2R) expression was assessed, using anti-Tac monoclonal antibody, after incubation of human lymphocytes with the beta-adrenoceptor antagonist propranolol (PRO). One-hour incubation of mononuclear cells (MNC) with PRO resulted in an increase of Tac positive cells. The greatest rise was observed with a PRO concentration of 10(-6) M (29% ring-stained cells compared with 0% in the control group). Cells cultured for 3 days with PRO showed a lower proportion of Tac positive cells (11%). Fifty-one per cent of MNC cultured with PHA for 3 days expressed IL-2R. Addition of PRO to PHA cultures increased IL-2R expression even more (65%). Enhancement of IL-2R expression after only 1 h incubation with PRO may be due to exposure of formerly synthesized receptor, which can be uncovered by some agents such as PRO.

Adult↗
PubMed1985

Changes in the interleukin-1 and interleukin-2 generation in duodenal ulcer patients during cimetidine treatment.

The effect of cimetidine treatment on the generation of interleukin-1 (IL-1) and interleukin-2 (IL-2) was studied in 11 duodenal ulcer patients. The results obtained were compared with those for untreated healthy subjects. The drug was administered intravenously in a dose of 200 mg four times a day for 8 days. The investigations were performed before, during and 1 wk after cimetidine therapy. IL-1 generation was determined by the ability of supernatants from 2-day cultured adherent cells stimulated by lipopolysaccharide to enhance proliferation of PHA-stimulated mice thymocytes. IL-2 generation was determined by the ability of supernatants from 2-day cultured, PHA-stimulated mononuclear cells to proliferate autologous 17-day cultured T cells. In all ulcer patients IL-1 generation diminished during cimetidine treatment (P less than 0.005). It continued to decrease in 4 subjects and increased in the other 7 ones following drug withdrawal. All the values were higher than those in healthy controls. IL-2 activity in ulcer patients was similar to that in healthy subjects and it increased significantly in all ulcer patients following the onset of the treatment (P less than 0.005) and decreased nearly to the initial values 1 wk after termination of the treatment (P less than 0.005). The present studies indicate that cimetidine, a selective histamine H2-receptor antagonist, deeply changes mechanisms of immunoregulation in patients with duodenal peptic ulcer.

Adult↗
PubMed1985

Phagocytic and bactericidal activities of neutrophils in duodenal ulcer patients during cimetidine treatment.

Phagocytic and bactericidal activities of neutrophils relative to Staphylococcus aureus 209 P strain were studied in 16 duodenal ulcer patients who were intravenously administered cimetidine in doses of 4 X 200 mg for 8 days and in a group of untreated healthy subjects. The investigations were made before the treatment on the last day of cimetidine administration, and one week after drug withdrawal. The bactericidal activity of neutrophils was found to be higher in duodenal ulcer patients than in the healthy controls. Cimetidine does not have a significant effect on the phagocytic activity of neutrophils and it has a moderately inhibitory effect (p less than 0.05) on the bactericidal activity relative to the ingested intracellular bacteria. This shows that cimetidine may modify some of the neutrophil functions in duodenal ulcer patients.

Adult↗
PubMed1984

The effect of cimetidine treatment on suppressor T cells in duodenal ulcer patients.

Changes in the suppressor T-lymphocyte activity were studied in 11 patients with duodenal ulcer during treatment with cimetidine. The drug was administered intravenously in a dose of 200 mg four times a day for a fortnight. Suppressor T-cell activity was determined by the Shou et al. method using two-stage culture before treatment, after 4 days of the treatment, just before drug withdrawal, and 2 days and 2 wk after the treatment. Suppressor T-cell activity significantly decreased soon after starting the treatment, remained low throughout the treatment, and rapidly and significantly increased following drug withdrawal.

Adult↗
PubMedDate not supplied

Short-term somatostatin infusion affects T lymphocyte responsiveness in humans.

Peripheral blood lymphocytes (PBL) function was analysed in 16 young men with duodenal ulcers after one-hour intravenous infusion of somatostatin (SMS) at a dose of 250 micrograms/h. Proliferative responses of PBL from SMS-treated patients were significantly diminished compared with pre-treatment values, after stimulation with PHA, PWM or Con A. Spontaneous IL-2R expression was moderately increased after SMS infusion but PHA-induced IL-2R expression was not affected by this drug. Alloantigen and autoantigen stimulation of PBL showed no significant changes in the proliferative response after SMS infusion. NK cell activity was similarly unaffected. These observations establish a link between SMS exposure and possible development of immune dysfunction.

Adult↗
PubMedDate not supplied

Some mechanisms of immunosuppressive action of epinephrine in humans.

The studies were performed on 12 men (9 duodenal ulcer patients and 3 healthy controls) aged 19-23 years. They were given epinephrine in a dose of 0.014 mg/kg subcutaneously. Blood samples were drawn before and 30 and 150 min. after drug injection. The results obtained in the duodenal ulcer patients and controls revealed the same direction of changes. Epinephrine induced a significant increase in the absolute numbers of all investigated peripheral blood mononuclear cell subpopulations (total lymphocytes, T, Th, Ts, NK cells and monocytes) observed at 30 min. following injection, while they nearly normalized at 150 min. A Th/Ts cell number ratio slightly, but significantly, decreased. Epinephrine did not affect spontaneous IL-2 receptor expression and it significantly inhibited PHA-induced IL-2 receptor expression and IL-2 generation at 30 min. following injection. NK cell activity also decreased 30 min. after epinephrine administration and it was still lowered at 150 min. The drug very distinctly inhibited proliferative response in the autologous mixed lymphocyte reaction test.

Adult↗
PubMedDate not supplied

The stimulatory effect of a single intravenous dose of propranolol of some immune parameters in humans.

Propranolol (PRO) is a beta-adrenergic receptor antagonist. The studies were aimed to evaluate the effect of a single intravenous PRO injection at a dose of 0.1 mg/kg on some immune parameters, and were performed on 12 men, including 9 duodenal ulcer patients and 3 healthy subjects, aged 19-23 years (mean 20.5 +/- 1.2). Blood samples were drawn before, 30 and 150 min following the injection. Results obtained in duodenal ulcer patients and healthy subjects revealed the same type of changes. A single PRO injection did not significantly affect total peripheral blood lymphocyte, Th cell and monocyte counts; however, it slightly but significantly lowered numbers of T and Ts cells, which was accompanied by a rise in Th/Ts cell number ratio and NK cell numbers. PRO significantly augmented spontaneous as well as PHA-stimulated IL-2 receptor expression, IL-2 generation, NK cell activity and AMLR observed at 30 and 150 min after the drug injection. Possible mechanisms of these changes are discussed.

Adult↗
PubMedDate not supplied

Effect of a single intravenous dose of verapamil on some immune parameters in duodenal ulcer patients.

The effect of a single intravenous dose of calcium channel blocking agent verapamil (VER) on immune parameters in humans remains uncertain. In this study the effects of VER on lymphocyte subpopulations, interleukin 1 (IL-1) and 2 (IL-2) production in vitro, autologous mixed lymphocyte reaction (AMLR), IL-2 receptor expression (Tac positive cells) and natural killer (NK) cell activity were assessed. The investigations were undertaken on 12 hospitalized men, aged 19-23 years, with small abdominal complaints. None of them had active duodenal ulcer disease, while in the remaining no signs of organic disease were found. VER was given intravenously in a dose of 0.15 mg/kg and examinations were performed on peripheral blood mononuclear cells (PBL) drawn before and 30 and 150 min following VER injection. The single VER dose induced a significant, but transient increase in T, T helper, T suppressor lymphocytes and monocytes, and decrease in IL-1 and IL-2 generation as well as diminished Tac antigen expression. These data provide evidence that calcium channel blockers may transiently disturb immunoregulation.

Adult↗