Biomedical subjects

T Motyl

Publications and source records attributed to T Motyl.

At least 37 records · Page 2Linked to original sources

PubMed1998

[Antioxidative mechanisms in response to reactive forms of oxygen, apoptosis and differentiation of myogenic cells].

In this paper regard was put on contemporary matters related to apoptosis of myogenic cells of different types (myocardium, visceral, skeletal muscle) and updated theories on the action mechanisms of free radicals and their contribution to this process. Concern was put on the activity of certain growth factors and antioxidants belonging to group of polyphenols on the extent of apoptosis in myoblasts held in culture. Similarities between the pathways depicting the process of muscle differentiation and resistance to programmed cell death are presented. The concept of myogenic cell differentiation and implications to apoptosis induced by particular oxidants is extensively discussed.

Animals↗

PubMed1997

Polyamines in goat's colostrum and milk.

The concentration and secretion of putrescine (PTR), spermidine (SPD), and spermine (SPM) was examined in colostrum and milk of 60 dairy goats (Polish White and German Brown) during 90 days of lactation. It has been found that milk polyamine pattern is related to breed, age, offspring number, lactation period, milking time, and individual goat-to-goat variations. The mean level of PTR and SPD was significantly higher, whereas SPM level was significantly lower in German Brown than Polish White goats. These differences were maintained during whole observation period (90 days after parturition). Elder goats, bearing two and three kids, secreted colostrum with a higher concentration of PTR and a lower concentration of SPD than young goats having one kid. There was a highly significant positive relationship between the age or litter total weight and PTR concentration in colostrum of Polish White goats. In contrast to PTR, the SPD level was negatively correlated with the age or litter total weight. The daily secretion of PTR, SPD, and SPM progressively increased from the 1st to 90th day of lactation. It was dependent on the increase of milk secretion rate, which could be illustrated by the highly significant correlation between daily milk yield and secretion of SPD in milk of German Brown and Polish White goats. The concentration of SPD in milk sampled in the evening was usually higher than in that from morning milking, however, significant only in the case of German Brown goats. In general, goat's colostrum and milk are rich in polyamines, which the total concentration is the highest when compared to milk of other mammals examined so far (e.g., human, rat, sow, and cow).

Animals↗

PubMed1997

Apoptosis and Bcl-2 protein changes in L1210 leukaemic cells exposed to oxidative stress.

The aim of this study was to explore the dose- and time-dependent effects of hydrophilic peroxyl radical initiator 2,2'azobis(2amidinopropane)dihydrochloride (AAPH) on apoptosis, and on expression of Bcl-2 in L1210 leukaemic cells. We observed a progressive increase of intracellular concentration of oxygen free radicals (OFR), manifested by the rise of 6-carboxy-2', 7'-dichlorodihydrofluorescein diacetate, di(acetoxymethyl ester) oxidation, during 24 h of cells exposure to AAPH. Oxidative stress was associated with peroxidation of cellular lipids, which was demonstrated by the measurement of thiobarbituric acid-reactive substances and conjugated dienes. Analysis of cell viability by the use of trypan blue exclusion method revealed that AAPH reduced the ability of L1210 cells to multiply or survive. AAPH increased the number of leukaemic cells with typical features of apoptosis like condensation of chromatin, pyknosis and fragmentation of nucleus, followed by secondary necrosis. A characteristic internucleosomal DNA cleavage, visualized as a DNA 'ladder' consisting of fragments that are multiples of 180-200 bp was also observed. The intensity of apoptosis was dependent on AAPH concentration, time of cell exposure and the availability of growth factors and nutrients in extracellular environment (FCS concentration). The novel observation is the increase of Bcl-2 level in L1210 leukaemic cells surviving an oxidative stress. The level of Bcl-2 protein significantly rose with increasing AAPH concentration, and time of cell exposure to this oxidant. This phenomenon could be the result of: (1) negative selection of cells with the lowest expression of bcl-2, being more susceptible to oxidative stress and (2) increased synthesis and/or decreased degradation of Bcl-2 protein as an adaptation to continuous OFR loading. In contrast to growth-promoting medium (10% FCS/RPMI), the maintenance medium (2% FCS/RPMI) did not cover cell requirements for progressive Bcl-2 increase at the highest AAPH concentration (2 mM) applied in this study. Several observations indicate that the increased Bcl-2 level in surviving L1210 leukaemic cells exposed to oxidative stress is a symptom of their natural defence against cellular lipids peroxidation and apoptosis.

Journal Article↗

PubMed1996

Phorbol ester (12-O-tetradecanoylphorbol 13-acetate) prevents ornithine decarboxylase inhibition and apoptosis and L1210 leukemic cells exposed to TGF-beta 1.

Previous studies have shown that growth suppression and apoptosis of leukemic cells exposed to TGF-beta 1 is associated with the inhibition of ornithine decarboxylase (ODC)--the key enzyme of polyamine pathway. The aim of the present study was to evaluate the influence of 12-O-tetradecanoylphorbol 13-acetate (TPA)--a potent ODC inducer on antiproliferative and apoptotic effects of TGF-beta 1 in L1210 leukemic cells. Cells were incubated in 2% FCS/RPMI-1640 medium, supplemented with TGF-beta 1 (2 ng/ml). TPA (100 ng/ml) or alpha-difluoromethylornithine (DFMO) (5 mM). Cell proliferation, apoptosis and necrosis were evaluated using [methyl-3H] thymidine, electron microscopy, electrophoresis of DNA and trypan blue exclusion. Expression and activity of ODC were determined by RT-PCR and measurement of 14CO2 release from L-1-14C ornithine, respectively. TGF-beta 1 inhibited proliferation and induced apoptotic and necrotic cell death in L1210 leukemic cells. The above effects were associated with the inhibition of ODC expression and activity, measured 2 and 4 hr after TGF-beta 1 administration, respectively. The presence of DFMO, an irreversible inhibitor of ODC, led to apoptotic fragmentation of DNA, similar to that observed in TGF-beta 1-treated cultures. Administration of TPA simultaneously with TGF-beta 1 significantly reduced antiproliferative, apoptotic and necrotic effects of TGF-beta 1, and prevented its inhibitory action of ODC expression and activity. It is concluded that: down-regulation of ODC expression may be one of the early events associated with TGF-beta 1-evoked suppression of growth and apoptosis; ODC is involved in the mechanism of protective action of TPA on TGF-beta 1-related growth inhibition of L1210 leukemic cells.

Animals↗

PubMed1995

Polyamines in cow's and sow's milk.

There were considerably interspecies, individual, lactation and age related variabilities in the concentration of spermidine and spermine in cow's and sow's milk. Concentration of spermidine was similar in cow's and sow's milk, whereas spermine level was higher in sow's milk. The level of spermine was higher than spermidine throughout the lactation in sow's milk, whereas spermine in cow's milk was secreted only at the beginning of lactation (collostrum and milk of the first month of lactation). The peak of spermidine and spermine concentration occurred in the collostrum and milk between the 1st and 3rd week of lactation in cow and sow, respectively. There was a significant positive relationship between milk yield and spermidine secretion in cow as well as between the number of piglets and milk spermidine concentration in sow.

Age Factors↗

PubMed1995

Effect of orotic acid on TGF-beta 1-induced growth inhibition of L1210 leukemic cells.

UNLABELLED: Transforming growth factor-beta 1 (TGF-beta 1) exerted growth-inhibitory effect on L1210 leukemic cell line, manifested by the decrease in viable and increase in dead cells. The cell death evoked by TGF-beta 1 was both necrotic and apoptotic, quantified by the trypan blue exclusion method and apoptotic index, respectively. The induction of programmed cell death by TGF-beta 1 was confirmed by gel electrophoresis of DNA, where the characteristic 'DNA ladder' resulting from the internucleosomal DNA cleavage was visualized. The enhancement of cell mortality by TGF-beta 1 was associated with the inhibition of ornithine decarboxylase (ODC) expression (measured by the reverse transcriptase-polymerase chain reaction method) and impaired activity of this key enzyme in polyamine synthesis. Orotic acid (OA)--a known tumor promoter--stimulated proliferation of L1210 leukemic cells and diminished the necrotic effect of TGF-beta 1, but it did not change the extent of apoptosis evoked by TGF-beta 1. OA increased the expression of ODC and diminished depressional influence of TGF-beta 1 on transcription and activity of ODC in leukemic cells. IN CONCLUSION: OA is a bioactive compound stimulating the growth of leukemic cells and diminishing the growth-inhibitory effect of TGF-beta 1. ODC gene is probably one of the targets for both OA and TGF-beta 1 influences in L1210 leukemic cells.

Animals↗

PubMed1995

The effect of OA on proliferation and polyamine metabolism of K 562 leukemic cells and their responsiveness to natural killer cell activity.

Orotic acid (OA), a known promoter of carcinogenesis, significantly stimulated proliferation of K 562 leukemic cells even at as high a concentration as 0.1 mM. This effect was accompanied by a significant increase of the activity of two key enzymes of the polyamine pathway, i.e. ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC). The induction of ODC activity was associated with increased expression of the ODC gene. The participation of ODC in early events evoked by OA in leukemic cells was confirmed by the decrease of the stimulatory effect of OA on cell proliferation in the presence of alpha-difluoromethylornithine (DFMO)--an irreversible inhibitor of ODC. The involvement of protein kinase C (PK-C) and cyclic nucleotide-dependent kinases in OA action on K 562 leukemic cells was demonstrated by a significant reduction of cell proliferation by addition of H-7 (1-(5-isoquinolinesulphonyl)-2-methylpiperazine). Since PK-C is involved both in induction of ODC activity and in membrane transport of polyamines, H-7 significantly inhibited the proliferation of K 562 leukemic cells even in the presence of OA and exogenous putrescine. The importance of extracellular sources of polyamines for leukemic cell growth was shown by supplementation of the incubation medium with putrescine. Exogenous putrescine significantly enhanced the concentration of spermidine and spermine within the cell and increased the number of cells. The effect of OA on natural killer (NK) cell cytotoxicity was also examined. Rat peripheral blood mononuclear cells were used as effector cells and K 562 cells as targets. OA, progressively with dose, significantly decreased specific lysis when targets were preincubated with it. On the other hand, pretreatment of PBMC effector cells with OA, regardless of the applied concentration, did not affect the amount of 51Cr released from lysed cells. OA as a promoter of carcinogenesis stimulates proliferation of leukemic cells and impairs their responsiveness to NK activity. ODC/polyamine system and PK-C appear to be involved in OA action on K 562 cells. The presented observations are important from a practical point of view, since an elevated blood concentration of OA resulting from the impaired kidney function in hematological proliferative diseases may accelerate their progression.

Base Sequence↗

PubMed1994

Involvement of polyamines in epidermal growth factor (EGF), transforming growth factor (TGF)-alpha and -beta 1 action on culture of L6 and fetal bovine myoblasts.

1. alpha-Difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase significantly abolished stimulation of protein synthesis evoked by EGF, TGF-alpha or -beta 1 in L6 and fetal bovine myoblasts. 2. The participation of polyamines in early events evoked by growth factors was shown by a significant stimulation of ornithine decarboxylase and S-adenosylmethionine decarboxylase activity as well as increased concentration of spermidine and spermine in L6 cells exposed to TGF-alpha and EGF. 3. TGF-beta 1 at a high concentration (1 ng/ml) increased protein synthesis in L6 myoblasts but inhibited it in fetal bovine myoblasts. Metabolic effects of TGF-beta 1 in L6 cells was associated with an enhancement of decarboxylase activities, however there were no significant changes in cellular polyamine concentrations. Presented data suggest that polyamines are involved in the signal transduction pathway of EGF, TGF-alpha, and -beta 1 in L6 and fetal bovine myoblasts.

Adenosylmethionine Decarboxylase↗

PubMed1994

Polyamines and pyrimidines in blood plasma and urine of dogs bearing mammary tumours.

The blood plasma and urinary pattern of polyamines and pyrimidines in dogs bearing mammary tumours was examined. A large variability of pyrimidines in blood plasma and spermidine, spermine and pseudouridine in urine of healthy and tumour-bearing dogs was observed. The blood plasma level of uracil and uridine as well as urinary concentration of pseudouridine and spermidine/spermine ratio were significantly elevated in dogs with mammary tumours.

Animals↗

PubMed1993

TGF-beta 1 inhibits polyamine biosynthesis in K 562 leukemic cells.

The present study proved that TGF-beta 1 significantly inhibited the growth of K 562 cells. The drop in cell numbers after 24 h incubation with increasing concentrations of TGF-beta 1 (0.01, 0.1, 1.0, 10.0 ng/ml) was accompanied by significant suppression of the activity of two key enzymes of polyamine biosynthesis: ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC). In contrast to ODC and SAMDC activity, TGF-beta 1 did not significantly affect the absolute concentration of spermidine and spermine in K 562 cells. We suppose that the lack of an evident drop in concentration of spermidine and spermine in spite of a significant decrease in ODC and SAMDC activity in K 562 cells exposed to TGF-beta 1 resulted from the uptake of polyamines from the extracellular space.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1993

Comparison of metabolic effects of EGF, TGF-alpha, and TGF-beta 1 in primary culture of fetal bovine myoblasts and rat L6 myoblasts.

1. Comparative studies of EGF, TGF-alpha, and TGF-beta 1 action on the synthesis of DNA and cellular proteins in rat L6 myogenic cells and fetal bovine myoblasts demonstrated considerable differences between particular growth factors, dependent on dose and target cells. 2. Among examined growth factors only EGF exerted mitostimulatory action, more pronounced at lower concentrations. EGF, progressively with dose, stimulated protein synthesis much more effectively in fetal bovine myoblasts than in L6 cells. 3. The dynamics of stimulation of protein synthesis by TGF-alpha was greater than by EGF in both examined types of cell cultures. 4. The maximal response of fetal bovine myoblasts to TGF-alpha in a concentration of 100 ng/ml reached 370%, whereas EGF in a 10 times higher concentration stimulated protein synthesis only to 123% of control. 5. In contrast to EGF, TGF-alpha significantly inhibits DNA synthesis. Inhibition of the mitogenic response with simultaneous stimulation of protein synthesis by TGF-alpha may indicate changes toward cell differentiation. 6. TGF-beta 1 in smallest concentration inhibits both DNA and protein synthesis. The suppressive action of TGF-beta 1 was more distinct in fetal bovine myoblasts than in the L6 cell line. 7. Increasing concentrations of TGF-beta 1 diminished its inhibitory effect, even leading to stimulation of protein synthesis at higher doses in L6 myoblasts.

Animals↗

PubMed1993

Mitogenic effect of lymph, amniotic and allantoic fluid in bovine fetal myoblasts.

Amniotic and allantoic fluids, as well as afferent lymph (tissue fluid), stimulated DNA synthesis in bovine fetal myoblasts (BFM) at low concentrations (5%). Higher doses abolished the mitostimulatory effect of these fluids and led toward inhibition of [3H]mTdR incorporation into DNA. These effects were much more evident (particularly in the case of amniotic fluid) when fluids were lyophylized prior to the experiment. BFM protein synthesis was accelerated by lymph in a dose dependent manner.

Allantois↗

PubMed1993

Efficiency of hemodialysis of pyrimidine compounds in patients with chronic renal failure.

The accumulation in blood plasma and efficiency of hemodialysis of pyrimidine compounds (orotic acid, orotidine, pseudouridine, uridine, thymine) as well as uric acid and creatinine in 23 patients with chronic renal failure (CRF) was investigated. As a reference, the analysis of the above metabolites in the plasma of 30 healthy volunteers was performed. Among examined compounds, pseudouridine possessed the highest capability of accumulation in blood plasma (25 times higher concentration than physiological). It coincided with the lowest efficiency of pseudouridine hemodialysis (44%) and the longest T1/2 (relative to creatinine) in plasma. A significant linear correlation (r = 0.81, p < 0.001) between efficiency of creatinine and pseudouridine hemodialysis was calculated. The concentration of orotic acid in the blood plasma of patients before hemodialysis exceeded 14 times its level in healthy subjects; the inhibition of uric acid synthesis by allopurinol in dialyzed patients was accompanied by enlargement of orotidine and orotate accumulation in blood plasma. Extremely high plasma concentration of examined pyrimidines remaining elevated after hemodialysis creates an additional hazard for tissue metabolism and health of patients with CRF.

Adult↗

PubMed1993

Blood plasma pseudouridine in patients with malignant proliferative diseases.

The blood plasma concentration of pseudouridine was estimated in 104 healthy adult subjects, and 108 patients suffering from malignant proliferative diseases. The HPLC method for simultaneous determination of pseudouridine and creatinine was applied. The average physiological concentration of pseudouridine in blood plasma was 2.43 +/- 0.97 mumol.l-1 or 29.15 +/- 7.40 mmol.mol-1 creatinine. The physiological urinary excretion of pseudouridine was 14.32 +/- 5.20 mumol.24 h-1.kg-0.75 or 19.60 +/- 5.22 mmol.mol-1 creatinine. Renal clearance of pseudouridine and endogenous creatinine were 4.04 +/- 0.99 and 5.50 +/- 1.46 ml.kg-0.75, respectively. A positive correlation (r = 0.55, P < 0.01) was found between age (in the range 20-92 years) and blood plasma pseudouridine concentration (mumol.l-1). By expressing plasma pseudouridine in relation to plasma creatinine, the apparent influence of non-metabolic factors (age, renal insufficiency, blood dilution) on the plasma pseudouridine concentration were largely excluded. Among haematological proliferative diseases the highest values of plasma pseudouridine concentrations were observed in chronic lymphocytic leukaemia (8.19 mumol.l-1; 54.9 mmol.mol-1 creatinine) and multiple myeloma (7.02 mumol.l-1; 52.5 mmol.mol-1 creatinine). In multiple myeloma, but not in chronic lymphocytic leukaemia, the plasma pseudouridine concentration depended on the clinical stage. A lower, but still significant response in non-Hodgkin's lymphoma was noted (4.03 mumol.l-1; 40.88 mmol.mol-1 creatinine). A significant increase of the plasma pseudouridine concentration was characteristic of adenocarcinomas of the large intestine, and it occurred in the early stages of malignant growth. In patients with lung cancer the plasma pseudouridine concentration was elevated only in advanced cases with metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Comparison of urinary neopterin and pseudouridine in patients with malignant proliferative diseases.

The HPLC method for the simultaneous determination of urinary neopterin, pseudouridine, and creatinine allows a rapid evaluation of the activation state of cell-mediated immunity, and the stimulation of whole-body rRNA + tRNA turnover, associated with malignant growth. Urinary neopterin and pseudouridine concentrations in healthy subjects amounted to: 106.6 +/- 34.6 mumol/mol creatinine, and 19.6 +/- 5.2 mmol/mol creatinine (mean +/- SD), respectively. The increase of neopterin excretion in patients with haematological neoplasms ranged from 146% in Hodgkin's disease to 534% in non-Hodgkin's lymphoma, whereas the increase in cancer cases ranged from 95% in adenocarcinoma of the gaster to 741% in hepatocellular carcinoma. The changes in pseudouridine excretion were much less pronounced: 63% in non-Hodgkin's lymphoma and 120% in carcinoma of the urinary bladder. The correlation coefficient between neopterin and pseudouridine was relatively low (r = 0.43), although statistically significant (P < 0.01). In the case of several neoplasms e.g. Hodgkin's disease, polycythaemia vera, and adenocarcinoma of the gaster, neopterin was significantly elevated, whereas pseudouridine remained at a normal concentration. There was a positive relationship between the stage of the disease (primary focus, regional metastases, dissemination) and urinary concentration of pseudouridine in patients with adenocarcinoma of the large intestine. In the same patients the increase of neopterin excretion was noticed both in early and advanced stages, with the highest values in disseminated disease.

Analysis of Variance↗

PubMed1993

Metabolic effect of orotic acid in rat L6 myoblasts.

Orotic acid (OA) is an intermediate in the pyrimidine pathway. The main source of OA in the human and animal diet is bovine milk and its products. OA significantly inhibited the stimulation of protein synthesis by FCS derived growth factors in L6 myoblasts. An increasing OA concentration (0.001 mM, 0.01 mM, and 0.1 mM) in a medium containing 2% FCS decreased the proliferation of L6 myoblasts (as measured by the number of cells) as well as the incorporation of traced thymidine into cellular DNA after 24 h incubation. This mitoinhibitory effect was accompanied by a significant reduction of ornithine decarboxylase (ODC) activity, an enzyme which is believed to be a valuable index of cell proliferation. A drop in the cytosol spermine level of L6 myoblasts treated with OA also occurred. A simultaneous, significant, compensative increase of S-adenosylmethionine decarboxylase (SAMDC) activity was noted. The addition of putrescine (2 microM), a product of ODC activity, abolished the depressional influence of OA on protein synthesis in L6 myoblasts, thus confirming its interference with the polyamine pathway. Dibutyryl-cAMP (0.05-0.2 mM) or adenine (25 microM) supplementation, regardless of OA concentration, significantly attenuated the mitoinhibitory effect and its inhibitory action on protein synthesis. This may suggest the existence of a purine deficiency in OA-treated myoblasts. These experiments indicate that increasing cellular OA concentration inhibits cell growth probably by disturbances in the chain of early events (synthesis of cyclic purine mononucleotides, and activity of the ODC/polyamine system), normally evoked by growth stimulating factors.

Adenine↗

PubMed1992

The metabolism and urinary excretion of orotic acid in hyperargininaemic sheep.

The synthesis, blood plasma turnover and urinary excretion of the orotic acid in normo- and hyperargininaemic sheep was investigated. The whole-body orotate formation was evaluated indirectly by the measurement of urinary orotate excretion after blockage of pyrimidine pathway with 6-azauridine (4 hour i.v. infusion of 0.2 mg.kg-1.min-1). Simultaneous infusion of L-arginine (2.5 mumols.kg-1.min-1) significantly elevated the blood plasma arginine, ornithine and urea level, however, it did not significantly influence urinary orotate excretion. In normoargininaemia blood plasma turnover of exogenous orotic acid amounted to 4.9 min and 67% of this compound was eliminated through the kidneys. The renal clearance of orotic acid amounted to 21.7 ml.min-1.kg-0.75. Hyperargininaemia elevated blood plasma turnover to 8.2 min, and diminished the renal clearance of this metabolite to 13.7 ml.min-1.kg-0.75. These results indicate that hyperargininaemia and hyperornithinaemia do not change the whole body synthesis of orotic acid in sheep but they can affect renal excretion of this metabolite, particularly at the rate of tubular secretion close to saturation.

Animals↗

PubMed1991

Urinary excretion of purines in sheep with experimental orotic aciduria.

Urinary excretion of uric acid, hypoxanthine, allantoin, and urea was measured in sheep (Polish Merino, about 20 kg b.w.) with experimental orotic aciduria. The 240 min infusion of 6-azauridine solution into the jugular vein induced a highly significant increase of urinary orotic acid, uric acid and hypoxanthine excretion. No differences were found in relation to excretion of allantoin and urea in examined sheep. It was calculated that renal clearance of uric acid and hypoxanthine increased significantly in response to 6-azauridine infusion. Intravenous infusion of sodium orotate evoked a highly significant elevation of renal urate clearance. No significant change in renal urea clearance was observed. The data suggest that competition between the renal transport of orotate and actively transported purine compounds (uric acid and hypoxanthine) occurs.

Allantoin↗