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Biomedical subjects

B Płytycz

Publications and source records attributed to B Płytycz.

At least 19 recordsLinked to original sources
PubMed1999

Depletion of head kidney neutrophils and cells with basophilic granules during peritoneal inflammation in the goldfish, Carassius auratus.

The head kidney morphology of the goldfish with the experimental peritoneal inflammation (on day 2 after i.p. injection with sterile 3% Thioglycollate) is compared with that in the control fish (i.e. on day 2 after i.p. injection with a strile physiological saline PBS) with special emphasis on identification of granulocytes on semithin and consecutive ultrathin sections. The most striking feature of head kidneys of goldfish in the course of peritoneal inflammation is a severe depletion of mature neutrophils and cells with basophilic granules (basophils/mast cells). These observations suggest the involvement of the head kidney, the main hematopoietic organ of teleosts, in the inflammatory process.

Animals↗
PubMed1998

MHC molecules and lymphocytes: evolutionary perspective.

The classical polymorphic MHC molecules of class I or class II bind peptides derived from the processed cytosolic or endosomal antigens and export them to the cell surface for presentation to the T cell receptors (TcR) of CD8 or CD4 T lymphocytes, respectively. The classical MHC molecules are unstable when peptides are not bound. The MHC-peptide-TcR interactions constitute a molecular basis of thymic selection of the major streams of alpha beta and gamma delta T lymphocytes. The monomorphic MHC class I-like molecules (class Ib) bind peculiar peptides or nonpeptide antigens or can keep proper conformation even without antigenic peptides. They are recognized by the specialized subsets of nonconventional lymphocytes, mainly extrathymic gamma delta T or natural killer (NK) T lymphocytes. The most unorthodox T lymphocytes can see antigens directly without the participation of MHC or MHC-like molecules or can see MHC-like molecules not loaded with peptides. The conventional B2 lymphocytes are indirectly dependent on MHC-peptide-TcR interactions as they can bind the epitopes of native antigens via Ig surface receptors, to be activated they must present the processed antigens via the MHC class II molecules to the Th2 lymphocytes. In contrast, the B1 lymphocytes can be activated directly without cooperation with T cells via MHC molecules. It seems that both MHC molecules and lymphocyte antigen receptors arose by the expansion of Ig-superfamily genes at the early steps of vertebrate phylogeny. The nonconventional T lymphocytes (gamma delta T cells and NK T lymphocytes) and B1 cells which support innate immunity at the body surfaces or cavities as well as the MHC-like molecules might appear earlier, creating a proper microenvironment for development of the conventional T and B2 subsets of lymphocytes.

Animals↗
PubMed1997

Characterization of opiate binding sites on the goldfish (Carassius auratus L.) pronephric leukocytes.

The head kidney is the main lymphopoietic organ of teleost fish. It is the source of leukocytes inhabiting the peritoneal cavity during an experimental peritoneal inflammation (Gruca et al., Folia Biol.-Kraków, 1997, 44, 137-142). The number of elicited peritoneal leukocytes is significantly lower in the goldfish with concomitant morphine injection than in their counterparts injected with the irritant only. Morphine may act directly on the head kidney leukocytes, as they are equipped with the selective naloxone-binding sites (Chadzińska et al., Arch. Immunol. Ther. Exp., 1997, in press). Further characterization of these opioid receptors (by radioligand binding techniques) indicates that the goldfish head kidney leukocytes possess at least two different opiate-binding sites: the [3H]naloxone binding site with a KD = 87 +/- 2.1 nM and Bmax = 298 +/- 15 fmol/mg protein; and the second, the [3H]naltrindole binding site with a KD = 37 +/- 5.5 nM and Bmax = 1,172 +/- 220 fmol/mg protein. The competition experiments with delta- (naltrindole), kappa- (nor-binaltorphimine) and mu- (cyprodime, naltrexone) selective ligands suggest that the naloxone-binding site is similar to mu 3 receptors described by Stefano et al. (Proc. Nat. Acad. Sci. USA, 1993, 90 11099-11103). Low affinity binding of selective ligands excludes the presence of neuronal-type mu- and delta-opioid receptors on goldfish leukocytes.

Animals↗
PubMed1997

Morphine modulation of thioglycollate-elicited peritoneal inflammation in the goldfish, Carassius auratus.

Intraperitoneal (i.p.) injection of adult goldfish with 3% thioglycollate (TG) induces an acute peritoneal inflammation connected with a massive influx of inflammatory leukocytes mainly of the head kidney origin. The number of peritoneal exudate cells retrieved on day 2 of the inflammatory response is significantly lower in fish injected with TG and morphine (20 mg/kg b.w.) than in animals injected with TG only. The morphine effect was totally antagonized in fish injected 20 min earlier with naltrexone (1 mg/kg), a well-known blocker of opioid receptors. Light microscopy of the head kidney Epon sections revealed that basophilic granulocytes are common in the control PBS-injected fish and even more frequent in fish injected with morphine only. In sharp contrast basophils are very rare in the head kidneys from animals with the TG-induced peritoneal inflammation, while they are more numerous in fish injected with TG and morphine. Supposedly, the basophilic granulocytes might be involved in the inhibitory effects of morphine on the acute inflammation in goldfish. An involvement of the head kidney in the morphine modulation of the inflammatory response is strongly supported by the detection of opioid receptors in the head kidney cells suspension.

Analgesics, Opioid↗
PubMed1997

Nitric oxide production by cells infiltrating amphibian skin grafts.

In vivo injection of the edible frog Rana esculenta with NOS inhibitor, L-NMMA caused prolongation of skin allograft and xenograft viability, statistically significant only in the latter case. In the present studies skin allo- and xenografts at the latent or rejection phase were excised from the hosts (Bufo bufo, R. temporaria, and R. esculenta) and incubated in vitro for 24 hrs in a medium only or in the presence of competitive (L-NMMA, L-NAME, L-aminoguanidyne) and noncompetitive (dexamethasone and cycloheximide) inhibitors of NO synthesis. In some experiments graft infiltrating cells were washed out and cultured separately from the respective skin fragments. The nitrite level was measured in the culture supernatant using Griess reagent. The nitrite level was negligible in the control skins, autografts, and xenografts depleted of graft infiltrating cells, as well as in allo- and xenografts excised at the rejection phase. In the case of grafts excised at the latent phase, the nitrite amount was substantial in supernatant from allografts and significantly higher in xenografts. A high level of nitrite was also present in supernatants from graft infiltrating cells. It is concluded that the NO contributes to some stages of the rejection process of the anuran skin grafts, this contribution being especially significant in the case of xenografts. The main source of this agent are graft infiltrating phagocytic cells.

Animals↗
PubMed1997

Rhythms of immunity.

Rhythms of daily activity are found in all vertebrate species, some of them being diurnal (like humans, dogs, pigeons), others--nocturnal (like mice, rats and bats). Some species undergo very pronounced seasonal changes, as they hibernate in the winter or mate only at the specific seasons. The main regulator (a clock and a calendar) for daily and seasonal rhythms is the periodicity of the external light-darkness, reflected by the periodicity of melatonin secretion from the pineal gland, which is inhibited by light and induced during the darkness. In contrast to melatonin which peaks during the night both in diurnal and noctural species, the cyclicity of other hormones and several immune parameters correlates with the pattern of the animal locomotor activity-resting. The immune parameter that peaks at one time of day for a diurnal species peaks about 12 h later for a nocturnal one. Various immune parameters peak at various time points, anticipating an encounter with pathogens during the period of activity while energetically expensive resolution of the immune response during the resting. Daily and seasonal cyclicity of the immune functions are temporally integrated with other physiologic and behavioral processes and all of them are regulated and coordinated with daily and seasonal changes of an external environment by the neuroendocrine homeostatic system.

Animals↗
PubMed1995

Thymic vascular system of the European common frog, Rana temporaria: a scanning electron-microscopic study of vascular casts.

Vascular corrosion casts of the thymus of adult individuals of the European common frog, Rana temporaria, were analysed by scanning electron microscopy. The main arterial vessel, which is derived either from the temporal artery or from the auricular ramus, approaches the central territory of the gland and branches into "twigs" that, on penetrating the parenchyma, give rise to capillaries. Most of these capillaries run vertically towards the surface of the gland; they either join the superficial capillary plexus or follow this plexus for a variable distance and then run back towards the medulla, forming capillary loops. The former capillaries link with the extensive venous plexus composed of irregular meshes, whereas the latter capillaries join the venules at the cortico-medullary boundary and finally escape into collecting veins on the gland surface. The venous twigs, which join together near the gland, form the main thymic vein, which empties into the external jugular vein. The details of the thymic vasculature of the anuran amphibian, R. temporaria, are compared with those described in mammalian species, viz. the mouse, rat and guinea pig.

Animals↗
PubMed1994

Studies on transplantation immunity of the yellow-bellied toad Bombina variegata.

Adults and tadpoles of the yellow-bellied toad Bombina variegata reacted in a typically chronic manner to skin allografts and to xenografts from closely related fire-bellied toads B. bombina but they rejected quickly skin xenografts from evolutionary distant anuran species (Bufo and Rana). Adult individuals reacted to allografts slowly not only in the laboratory where their mating was ceased and the weight of lymphoid organs significantly diminished but also in the outdoor enclosure where they bred successfully. Breeding activity in captivity can be induced at any season by Biogonadyl injections. However, any hormonal manipulation (gonadectomy or Biogonadyl treatment) performed during winter/spring on animals housed in the laboratory for several months did not influence their transplantation immunity and the weights of thymuses and spleens. These results lead to conclusion that chronic allograft rejection was not a laboratory artifact caused by a hormonal imbalance but rather reflected a weak donor-host genetic disparity connected with the low MHC polymorphism of Bombina species.

Animals↗
PubMed1994

Light and electron-microscopic observations on the thymic capillaries and postcapillary venules in Rana temporaria L.

The aim of this study was to examine thymic capillaries and capillary venules in a common frog, Rana temporaria, using the light (LM) and transmission electron microscopy (TEM) as well as scanning electron microscopy (SEM) of vascular corrosion casts. The endothelial cells of capillaries and postcapillary venules show in frog thymus mostly flat morphology. However, some postcapillary venules are lined with tall endothelial cells which are characteristic for the thymus-dependent areas of mammalian secondary lymphatic organs (high endothelial venules, HEV). Such endothelial cells occurring in frog thymus are ultrastructurally characterized by increased amount of cytoplasmic organelles, mainly rough endoplasmic reticulum, ribosomes and electron dense lysosome-like granules, as well as by deep intercellular clefts. In HEV-like vessels, lymphocytes were observed to adhere to the endothelial surface, migrate through the endothelium, or lay beneath the endothelial basement membrane in the perivascular space. These findings were corroborated by SEM of corrosion casts which revealed in some postcapillary venules or their segments the presence of irregular casts surfaces with numerous depressions and protrusions reflecting the cobblestone appearance of the tall endothelial lining. Such venules are fed directly by capillaries and begin with abrupt increase in the vessel diameter, accompanied by the appearance of deep endothelial imprints. Our results demonstrate in the frog thymus the presence of specialized, HEV-like segments of postcapillary venules, suggesting that besides its function as the central lymphoid organ, frog thymus may also function as a peripheral one.

Animals↗
PubMed1993

Effects of hydrocortisone on the lymphoid organs of Rana temporaria.

In vivo and in vitro effects of hydrocortisone hemisuccinate (HC) on the lymphoid organs were studied in the European common frog Rana temporaria. Single HC injection at the dose of 0.5 mg/g body weight induced rapid but fully reversible changes in thymuses and jugular bodies while its effect on spleens was negligible. In vitro studies confirmed HC-sensitivity of thymuses and jugular bodies and relative HC-resistance of spleens of this species. In vitro exposition of thymic and jugular body cell suspensions to 0.25-1.00 mg/ml HC solution revealed a dose-dependent and time-dependent impairment of sample activities associated with massive cell death as judged by MTT reduction assay and Trypan blue uptake, respectively. Evolutionary implications of these results are discussed.

Animals↗
PubMed1992

Quantification of neutral red pinocytosis by small numbers of adherent cells: comparative studies.

A colorimetric assay has been developed for studies on neutral red (NR) pinocytosis by small numbers (below 2 x 10(5)) of adherent cells cultured in 96 well plates. The NR uptake per cell mass was much higher in the sea urchin perivisceral adherent cells and human HL-60 cell line monolayers than in the murine and Atlantic salmon macrophages. The apparent difference points to the usefulness of this novel assay in comparative studies.

Animals↗
PubMed1991

Argentaffin mast cells in the thymus of the frog.

Mast cells are common in the thymic parenchyma of the European common frog, Rana temporaria. They are stained meta chromatically with toluidine blue and the majority of them are impregnated with silver during the argentaffin reaction. The latter phenomenon indicate that these cells store serotonin. At the ultrastructural level, mast cells contain specific granules with electron-dense and electron-lucent parts. The silver grains are located exclusively over the electron-lucent part of the mast cell granules indicating that serotonin is stored just in this compartment.

Animals↗
PubMed1989

Leukocytes of rainbow trout (Oncorhynchus mykiss) pronephros: cell types producing superoxide anion.

Fish pronephric and blood leukocytes yield a chemiluminescent response (CL) when stimulated appropriately. This response reflects the production of highly reactive oxygen derivatives which contribute to oxygen-dependent killing of targets such as pathogens and parasites. From suspensions of pronephric cells of the Rainbow trout, Oncorhynchus mykiss, we have obtained populations enriched for CL-positive cells. Four bands of cells were obtained using continuous gradients generated with 60% Percoll. The leukocytes of band II showed a very strong PMA-induced CL response, the magnitude of which was several times higher than that observed with equivalent numbers of cells form unseparated pronephric cell suspensions. Cells present in other bands were not significantly chemiluminescent. Flow cytometric analysis showed that band II contained large granular cells and small granular cells. Cytochemical analysis showed that this subpopulation was greatly enriched with neutrophils. Many band II cells adhere to glass whereas few band III cells do so. The glass-adherent cells loose their CL potential after a few days in vitro, whereas the nonadherent cells retain their CL responsiveness for at least a week in vitro.

Animals↗
PubMed1989

The effect of laboratory environment on the morphology of the spleen and the thymus in the yellow-bellied toad, Bombina variegata (L.).

The morphological changes were observed in the spleen and the thymus of the yellow-bellied toad, Bombina variegata, kept under standard laboratory conditions. The mean splenic weights of toads studied soon after capture in July and September were 16.0 mg and 17.7 mg, respectively. In contrast, the mean splenic weights significantly decreased in animals maintained in the laboratory from July till September (to 11.6 mg) and from July till December (to 6.8 mg). In the spleen of toads kept in the laboratory the lymphocyte aggregations were diminished in the white pulp while the amount of connective tissues increased both in the white and in the red pulps. Melano-macrophages were more abundant in the red pulp of toads kept in the laboratory than in freshly collected ones. The thymuses of toads kept in the laboratory were decreased in size and depleted of the majority of their cortical lymphocytes. It is suggested that the morphological changes of the yellow-bellied toad lymphoid organs might be the results of stressful laboratory conditions and lower antigenic stimulation in the laboratory than in nature.

Animals↗
PubMed1988

In vitro fusion of newt macrophages.

Spontaneous formation of multinucleate giant cells is often observed in in vitro cultures of peritoneal adherent macrophages from the newts, Notophthalmus viridescens and Taricha granulosa (urodele amphibians). The frequency of such giant cells in these cultures is increased by the addition of phorbol myristic acetate at the initiation of the cultures. This high frequency of multinucleate cells permitted us to evaluate whether multinucleate giant cells arise by cell fusion and/or by repeated nuclear division without cytokinesis. Cell fusion is readily detectable by scanning electron microscopy. To determine whether nuclear division without cytokinesis also occurs, some cultures were treated with colchicine to arrest mitotic figures; others were pulsed with tritiated thymidine to detect DNA synthesis. Mitotic figures were not seen in acridine orange-stained samples. In monolayers that were processed for autoradiography, only a few nuclei were marked with tritium. These observations suggest that nuclear division does not contribute significantly, if at all, to the formation of multinucleate giant cells from cultured newt peritoneal macrophages.

Animals↗
PubMed1987

Interdigitating cells in the thymus of the frog, Rana temporaria.

Interdigitating cells (IDC) of the thymic medulla of the frog, Rana temporaria, collected in the summer, were examined by electron microscopy. The most characteristic cytological features of IDC are voluminous electron-lucent cytoplasm and widespread interdigitations and invaginations of the cell membrane. IDC possess an excentrically located nucleus with pronounced nucleoli and a thin rim of a dense chromatine as well as a perinuclear area with characteristic tubulo-vesicular complex. In our material Birbeck granules were absent. Some IDC contain phagocytized material. A few transitional forms between monocytes and IDC were observed. On the basis of these observations it is highly probable that the amphibian IDC belong to the mononuclear phagocyte system.

Animals↗
PubMed1987

Hybrid resistance to the ascites form of the murine sarcoma.

An ascites form (AA) of the methylcholanthrene-induced murine sarcoma of C3H origin was used for present experiments. The AA cells were intraperitoneally injected to syngeneic (C3H, H-2k), allogeneic (DBA, H-2d) or semisyngeneic (C3H x DBA, H-2k/d) mice at a dose 10(7) cells per animal. The DBA mice developed small amount of ascites in the peritoneal cavity followed by rejection of allogeneic tumor cells and recovery. All syngeneic and semisyngeneic animals developed tumor and died. The C3H x DBA hybrids survived significantly longer than C3H mice (mean survival times: 21.9-24.8 and 10.1-11.8 days, respectively). The hybrid mice died with voluminous ascites tumor accompanied by a sponge-like form of tumor cell aggregates dispersed in the peritoneal cavity while the syngeneic mice died with small amount of dense ascites with an accompanying massive solid tumor in the vicinity of the spleen. Therefore in the experimental system used the semisyngeneic mice were found to develop a better response against parental-strain tumor cells than the syngeneic mice. This is an example of the phenomenon referred to as "hybrid resistance" or "allogeneic inhibition".

Animals↗