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A Lukaszyk

Publications and source records attributed to A Lukaszyk.

At least 37 records · Page 2Linked to original sources
PubMed1989

Does acute experimental pancreatitis affect blood platelet function?

The role of blood platelets in the disturbed haemostasis in acute pancreatitis is not fully elucidated. The aim of this study was to evaluate the blood platelet function during the first hours of acute experimental pancreatitis (AEP) in dogs. AEP was induced by the retrograde injection of bile and trypsin into the main pancreatic duct. Platelet count, platelet aggregation induced with ADP, PAF, AA as well as plasma Beta-TG and TXB2 levels were determined. At 30 min after induction of AEP a significant decrease of platelet count was noted; these changes were observed until 4 th hr. At 30 min as well as at 60 min of AEP increased sensitivity of platelet aggregation to ADP was found. After that time evident decrease of platelet aggregation to ADP was shown. Platelets sensitivity to PAF was higher at 30 min of AEP whereas 60 min, 2 and 4 hrs after AEP normalization of platelet aggregation by PAF was observed. The significant increase of plasma Beta-TG and TXB2 concentrations corresponded well to changes of platelet aggregation. These results indicate that AEP affects blood platelet function with the drop of their count.

Acute Disease↗
PubMed1985

Stimulatory effect of Sertoli cell secretory products on testosterone secretion by purified Leydig cells in primary culture.

We investigated the influence of media from nonstimulated (SCCM) and FSH-stimulated (F-SCCM) cultured rat Sertoli cells on testosterone secretion by purified rat Leydig cells maintained in culture for 4 days. Both SCCM and F-SCCM stimulated Leydig cell secretory activity to a level 2-6 times that of the control, the effect being always maximal on day 3 of culture. On day 3, concentrated SCCM had a greater stimulatory effect on testosterone secretion than the original (i.e. non-concentrated) one, the effect being dose-related and similar to that exerted by concentrated F-SCCM. On the other hand, original as well as concentrated F-SCCM stimulated the basal testosterone secretion in a dose-dependent manner on day 1 to about 200% and 400% of the control level, respectively, whereas SCCM exerted the 'early' effect only as a concentrated preparation. Preincubation of Leydig cells with F-SCCM enhanced both basal (190% control) and LH-stimulated (274% control) testosterone secretion when the LH (10 ng/ml) was added for 3 h on day 1. The enhanced influence of SCCM was noted only with the LH-stimulated cells (140% control). It is concluded that, in culture, Sertoli cells release at least 2 factors which enhance testosterone secretion by Leydig cells in vitro. One of them seems to be FSH-dependent and increases both basal and LH-stimulated testosterone secretion. This factor (MW greater than 1 kDa) is heat-labile and exerts its maximal effect between 12 and 18 h of culture. The second factor(s) acts predominantly on day 3 of culture, is apparently FSH-independent, and its influence on Leydig cell testosterone may be, at least in part, nonspecific.

Animals↗
PubMed1984

Stimulatory effect of Sertoli cell culture medium on the FSH release by pituitary halves in vitro.

The influence of the medium collected from cultured rat Sertoli cells on the spontaneous and LHRH-stimulated release of gonadotropins by incubated rat pituitary halves was examined. The homogeneity of the cultured population of Sertoli cells taken from 20-day-old rats ranged up to 98%. The cells in culture responded to FSH stimulation with characteristic morphological changes and with increased secretion of estradiol-17 beta. The hemi-pituitaries obtained from sexually mature male rats were incubated for 5 hours in the presence of Sertoli cell culture medium (SCCM) or its fractions obtained by use of ultrafiltration. The SCCM fraction deprived of MW less than 10 kD compounds exhibited a typical inhibin-like activity, whereas crude SCCM as well as its low-molecular-weight fraction stimulated the basal FSH release to about 150% and 175% of the control values, respectively. These fractions exerted an inhibitory effect on the LHRH-stimulated secretion of both LH and FSH. It is concluded that Sertoli cells cultured in chemically defined medium release, apart from inhibin, a non-steroidal, heat-labile substance of MW less than 10 kD which stimulates the basal secretion of FSH and LH and inhibits the LHRH-stimulated secretion of both gonadotropins from incubated rat hemi-pituitaries.

Animals↗
PubMed1984

The modified method for isolation and culture of highly homogeneous Leydig cell population from rat testes.

A modified method for isolation and culture of a pure population of rat Leydig cells is described. For obtaining crude interstitial cell suspension, decapsulated testes were dispersed in 0.02% collagenase solution in Ca2+, Mg2+--free Hanks medium for 1 hour. Then, approx. 5 X 10(7) cells were centrifuged in 10-90% discontinuous, isoosmotic Percoll gradient at 3000 g for 20 min. The cells from eight fractions obtained were collected and cultured in Eagle's MEM for 4 days. Using morphological methods, 1.059-1.070 g/ml density fraction contained 97% and 1.070-1.080 g/ml fraction contained 90% viable Leydig cells. The cells secreted testosterone to the culture medium and responded to LH stimulation with over four-fold increase in hormone secretion.

Animals↗
PubMed1983

The effect of strenuous exercise on the reactivity of the central dopaminergic system in the rat.

In rats subjected to physical strain the action of dopamine receptor agonists, amphetamine and apomorphine, was enhanced, but the effects of an antagonist, haloperidol, remained unchanged. The levels of biogenic amines in several brain regions were changed after the exercise. The results indicate that physical strain changes the functions of the central dopaminergic system in the rat.

Amphetamine↗
PubMed1982

Reactivity of the central nervous system in the disseminated intravascular coagulation in rats.

The reactivity of the central nervous system in the disseminated intravascular coagulation was studied. In this state the action of pentylenetetrazol and thiopental were decreased. Also shortening of tonic phase of electric convulsions was observed. No changes were noted in the contents of noradrenaline and serotonin, whereas slight increase in dopamine level in some regions of brain was found. It seems that observed effects are connected with other mechanisms than interaction with central mediators.

Animals↗
PubMed1982

Effect of increased fibrinolytic activity of rats blood on the action of some centrally acting drugs.

The action of some centrally acting drugs during high fibrinolytic activity of blood was studied. In these state the action of amphetamine increases and the action of thiopental and pentetrazol decreases. The observed changes may depend either on the altered pharmacokinetics of the compounds examined or on the neurohormonal background of the nervous tissue, changed under the influence of physical strain.

Amphetamine↗
PubMed1981

Culture of rat Sertoli cells isolated with a modified procedure. Morphological identification of cell population and cell reactivity.

The effects of growing of Sertoli cells isolated from rat seminiferous epithelium by a modified procedure, and responses of these cells to dBcAMP or FSH stimulation was estimated using morphological methods. The modified isolation procedure included repeated mechanical rinsing of tubule pieces with a modified EDTA containing Hanks medium. Moreover, streptornase instead DNase was added to the trypsine containing medium and this resulted in a better dispersion of tubule components. The culture conditions remained unmodified. A high degree homogeneity of the cultured cell population and an evident reactivity of these cells to dBcAMP and FSH was achieved. Furthermore, an observation of giant cells, visible in monolayer among the typical Sertoli cells, is discussed in this paper. Contrary to small number of myoid cells, being survived in the culture, these giant cells did not show positive reaction to alkaline phosphatase.

Animals↗
PubMed1975

Histophysiological evidence for the secretion of polypeptides by the pineal gland.

Histophysiological examinations of the bovine and monkey pineal gland indicate that this organ may be involved in the secretion of polypeptides. Using various histochemical procedures designed to identify peptide-secreting cells, granules and/or droplets of presumptive secretory product were identified within cellular processes, within the walls of blood vessels and associated with multilayered corpuscles (corpora arenacea). In bovine pineal tissue, the stained material was found most often in what appeared to be pinealocyte processes, as perivascular granules and associated with multilayered corpuscles. In the monkey pineal the stainable material was more distinct; this was probably due to the earlier fixation of the glands after death of the animals. In this species, the presumptive secretory material was found in nerve fibers, occasionally in glial cell and pinealocyte processes and within and around the walls of capillaries. In nerve fibers, the stained material sometimes resembled Herring bodies of the posterior pituitary gland. Similar material appeared to be located in capillary endothelial cells and within multilayered corpuscles. In pineal tissue of both species, calcium was detectable histochemically within multilayered corpuscles. Although tinctorially different, the presumptive neurosecretory material was similar to that found in the posterior pituitary gland. As a working hypothesis, we propose that polypeptides may be released from cells in conjunction with a carrier protein and that the mechanism of secretion of the polypeptide into the vascular system may involve its exchange for calcium. The calcium is then theoretically deposited in the multilayered corpuscles.

Animals↗