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J B Warchol

Publications and source records attributed to J B Warchol.

At least 19 recordsLinked to original sources
PubMed2001

Studies on the involvement of endogenous neuropeptides in the control of thymocyte proliferation in the rat.

The possible involvement of endogenous vasoactive intestinal peptide (VIP), cholecystokinin (CCK) and neurotensin (NT) in the control of thymocyte proliferation has been investigated in vivo in the immature rat. For this task, we have studied the effects of the administration of selective antagonists of the receptors of the three neuropeptides on the mitotic index (% of metaphase-arrested cells after vincristin injection) of thymocytes. Both CCK- and TN-receptor antagonists were ineffective. In contrast, two VIP receptor antagonists (VIP-As) enhanced the mitotic index of thymocytes. VIP reversed the effect of VIP-As, but when administered alone it did not alter the mitotic activity of thymocytes. In light of these findings, we conclude that endogenous VIP exerts a maximal tonic inhibitory influence on the basal proliferative activity of rat thymocytes, while endogenous CCK and NT do not play a relevant modulatory role in this process.

Animals↗
PubMed2001

Detection of Chlamydia trachomatis infection in women with CIN and invasive carcinoma. Controversial results of different methods.

Chlamydia (Ch.) trachomatis infection as a sexually transmitted disease is highly important, but reliable methods of diagnosing it remain to be worked out. We used three methods of detection: an immunoenzymatic technique for detection of Ch. trachomatis antigen in endocervical material, in situ PCR, and enzyme-immuno assay for detection of IgG class anti-Ch. trachomatis antibodies in serum. We have compared the IS-PCR technique and method of detection of the endocervical antigen. We have not confirmed compatibility of the results obtained in these two methods. Parallel positive results obtained in patient serum and detection of chlamydial DNA by IS-PCR have been accepted to be indicative of persistent infection of Ch. Trachomatis.

Adult↗
PubMed2000

Calcium confusion--is the variability in calcium response by Sertoli cells to specific hormones meaningful or simply redundant?

When results of more than ten different studies on hormone-induced calcium signals in Sertoli cells are taken together, a wide variety of responses emerges. The reported changes range from increased concentrations, via no response at all, to decreased calcium concentrations. Minor variations in cell isolation techniques, culture conditions, or techniques for measuring the intracellular calcium could explain some of these differences. However, erratic variations in response are also observed within research groups under very similar experimental conditions. Such 'negative' findings are mainly reported orally and do not further penetrate the scientific community. As hormone-dependent calcium responses evidently may depend very much on the context of the cells, calcium transients would appear to be unreliable bioassay principles with which to detect the primary actions of FSH and effectors such as androgens on Sertoli cells. A more important biological question is whether these sometimes opposed calcium transients are connected with a particular cellular response. To date there is no evidence for such a tight coupling in Sertoli cells, implying that, at least under in vitro conditions, calcium signals might even be redundant altogether. Such calcium variability is probably not unique to Sertoli cells, and the aim of this commentary is to promote an open debate that may help to transform the current state of 'calcium confusion' into a better understanding of the intracellular calcium language.

Animals↗
PubMed1997

Thymic nurse cells: their functional ultrastructure.

Thymic nurse cells are defined in vitro as multicellular complexes of epithelial cells and thymocytes. Although these structures have been implicated in the intrathymic differentiation of thymocytes, little is known about the biology of this cell complex and about the occurrence of the cells in the thymus in situ. Therefore, to clarify the matter, in this review we have presented characteristics of epithelial cells capable of forming complexes with thymocytes, in light of the literature data and the experience of the authors. The structure of cells within the complexes allowed us to distinguish three types of thymic nurse cells. Three-dimensional reconstruction of the thymus and observations employing TEM and SEM demonstrated the presence of distinct types of complexes in various topographic regions of the thymus. Where possible, the functional relevance of the morphological data was analyzed.

Animals↗
PubMed1996

Analysis of spermatozoa movement using a video imaging technique.

The aim of this paper is to present methods for a fully computerised analysis of spermatocyte movement. The technique were designed for processing pure images of spermatozoa captured from a light microscope. The techniques described allowed for the reduction of background light inhomogeneity and for the correct detection of moving cells and involved densitometric equalization of background inhomogeneity and implementation of the dynamic threshold, adopted for the recognition of objects. The method for relating cells (found in each frame processed) to movement trajectories used heuristic rules, describing the behaviour of moving cells. This permitted samples containing high numbers of spermatocytes within the observed area to be processed with maximum accuracy.

Humans↗
PubMed1996

Effects of substance P and its antagonist spantide on corticosterone secretion and cytosolic free calcium concentration of dispersed zona fasciculata-reticularis cells of the rat adrenal cortex.

Substance P (SP) did not change basal corticosterone (B) secretion of dispersed zona fasciculata-reticularis cells of the rat adrenal cortex. Conversely, spantide II (SPA), an antagonist of SP receptors, at a concentration 10(-7)/10(-6) M markedly raised it, and the effect was annulled by equimolar concentrations of SP. Both SP and SPA (10(-6) M) increased cytosolic free calcium concentration in our cell preparations; however, the response to SP was immediate, while that to SPA showed a lag-period of 4-5 min. SP concentration-dependently (from 10(-8) M to 10(-5) M) partially inhibited maximally ACTH (10(-8) M)-induced stimulation of B secretion of dispersed cells, and unexpectedly a similar effect was observed after SPA exposure. In light of these findings, the conclusion is drawn that SP, under basal conditions, does not exert a direct modulatory action of B secretion of rat adrenocortical cells. However, the possibility remains to be explored that SP may play a role in quenching, via a receptor-independent mechanism, the exceedingly high glucocorticoid responses to ACTH of rat adrenocortical cells.

Adrenocorticotropic Hormone↗
PubMed1995

Effects of neuromedin-K on the rat hypothalamo-pituitary-adrenal axis.

The effects of neuromedin-K (NMK) on the rat hypothalamo-pituitary-adrenal (HPA) axis were studied both in vivo and in vitro. A subcutaneous injection of 1 nmol/100 g NMK evoked a rise in plasma ACTH level at 30 min, increased plasma corticosterone (B) concentration (PBC) at 60 and 120 min, and did not alter plasma aldosterone (ALDO) concentration (PAC). The administration of 3 nmol/100 g NMK induced a rise in plasma ACTH level at 120 min and a drop of PBC at 30 min; it increased PBC and PAC at 60 and 120 min. NMK did not affect basal B secretion of dispersed zona fasciculata/reticularis (ZF/R) cells, but markedly enhanced basal ALDO production by dispersed zona glomerulosa (ZG) cells (minimal and maximal effective concentrations were 10(-9) M and 10(-7) M). Video-imaging analysis showed that NMK (10(-8) M) increased intracellular Ca2+ concentration in dispersed ZG cells, but not in ZF/R ones. These findings indicate that NMK exerts a complex modulatory action on the rat HPA axis: low doses of NMK appear to evoke a transient stimulation of ACTH release, while high doses seem to exert a short-term inhibition of glucocorticoid synthesis followed by the compensatory hypersecretion of ACTH; moreover, elevated doses of NMK also exert a strong ALDO secretagogue action by acting directly on the ZG cells.

Adrenal Glands↗
PubMed1995

Effects of neurokinin-A on the rat hypothalamo-pituitary-adrenal axis.

The effects of neurokinin-A (NKA) on the rat hypothalamo-pituitary-adrenal (HPA) axis were studied in vivo and in vitro. A subcutaneous injection of 1 or 3 nmol/100 g NKA did not alter plasma ACTH concentration. The lower dose of NKA evoked a transient rise in plasma corticosterone (B) concentration (PBC) at 30 min, and did not change plasma aldosterone (ALDO) concentration (PAC). The higher dose of NKA increased PBC at 30 and 60 min, and PAC at 30, 60 and 120 min. NKA did not affect basal ALDO secretion of dispersed zona glomerulosa (ZG) cells, but it markedly enhanced basal B production by dispersed zona fasciculata/reticularis (ZF/R) cells (minimal and maximal effective concentrations were 10(-9) M and 10(-6) M). Video-imaging analysis showed that 10(-6) M NKA increased intracellular Ca2+ concentration in dispersed ZF/R cells, but not in ZG ones. These findings indicate that NKA exerts a stimulatory action on the rat adrenal secretory activity, which is independent of any effect on the pituitary ACTH release: the B secretagogue action seems to be due to a direct effect of NKA on ZF/R cells, while the ALDO secretagogue action is not direct. but probably mediated by factor(s) other than ACTH.

Adrenocorticotropic Hormone↗
PubMed1994

Effects of neuromedin U-8 on the secretory activity of the rat adrenal cortex: evidence for an indirect action requiring the presence of the zona medullaris.

The acute effect of increasing concentrations (from 10(-8) to 10(-6) M) of neuromedin U-8 (NMU-8) on steroid secretion of rat adrenal gland was investigated in vitro by high-pressure liquid chromatography. The production of the following steroids was measured: pregnenolone (PREG), progesterone (PROG), 11-deoxycorticosterone (DOC), corticosterone (B), 18-hydroxy-11-deoxycorticosterone (18OH-DOC), 18-hydroxycorticosterone (18OH-B) and aldosterone (ALDO). NMU-8 had no effects on either dispersed adrenocortical cells or fragments of adrenocortical autotransplants lacking medullary chromaffin cells. Conversely, NMU-8 exerted concentration-dependent secretagogue effects on adrenal slices, including both cortex and medulla. At all concentrations tested, NMU-8 increased the production of both PREG and total post-PREG steroids. The increase in total post-PREG steroid output induced by low concentrations of NMU-8 (10(-8) M) was due to similar rises in the production of non-18-hydroxylated steroids (PROG, DOC and B) and 18-hydroxylated hormones (18OH-DOC, 18OH-B and ALDO); conversely, that provoked by higher concentrations of the neuropeptide (10(-7) to 10(-6) M) was almost exclusively caused by the rise in the yield of 18-hydroxylated steroids. The stimulating effect of NMU-8 on PREG output was blocked by both alpha-helical-CRH and corticotropin-inhibiting peptide, which are competitive inhibitors of CRH and ACTH, respectively. The following conclusions have been drawn: (1) NMU-8 affects adrenal steroid secretion indirectly by acting on the medullary chromaffin cells, which in turn may paracrinally stimulate the cortical ones; (2) at all concentrations tested, NMU-8, by stimulating the intramedullary CRH/ACTH system, causes a net rise in the activity of the early rate-limiting step of steroidogenesis, with the consequent increase in the output of the entire spectrum of post-PREG steroids; and (3) at higher concentrations (over 10(-8) M), NMU-8 also elicits the release from chromaffin cells of a factor (not yet known) that specifically enhances 18-hydroxylase activity.

Adrenal Cortex↗
PubMed1994

Effects of neuromedin U (NMU)-8 on the rat hypothalamo-pituitary-adrenal axis. Evidence of a direct effect of NMU-8 on the adrenal gland.

A 6-day subcutaneous (s.c.) treatment of adult rats with NMU-8 (1.5 or 6 micrograms/100 g/day) increased the average volume of zona fasciculata cells and decreased the number of zona reticularis cells in the adrenal cortex. The lower dose of NMU-8 did not change blood ACTH concentration and adrenal weight, but it notably enhanced serum corticosterone level and basal corticosterone output by adrenal slices. ACTH blood level increased after ether stress in both control and NMU-8-treated rats, but stress-evoked rise in serum corticosterone was observed only in control rats. The higher dose of NMU-8 increased the level of circulating ACTH; however, it decreased adrenal weight and had no effect on serum corticosterone concentration and basal corticosterone output by adrenal slices. NMU-8 (10(-10)/10(-6) M) did not affect basal and ACTH-stimulated corticosterone yield by isolated adrenocortical cells, nor did it change their cytosolic Ca2+ concentration. NMU-8 (10(-8) M) markedly raised basal corticosterone secretion by adrenal slices (including cortex and medulla); higher concentrations of NMU-8 (10(-7)/10(-6) M) were ineffective on basal corticosterone secretion, but strongly inhibited the response to ACTH stimulation. On the ground of these findings it seems reasonable to suggest that NMU-8 exerts a biphasic effect on the function of the peripheral branch of the hypothalamo-pituitary-adrenal axis in rats: NMU-8 at low doses directly stimulates the function and growth of the adrenal cortex, while at high doses exerts a direct inhibitory action.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1992

ACTH-induced ultrastructural changes in the zona fasciculata of the hamster adrenal cortex. Are intraadrenal thrombi regulators of corticosteroid secretion?

Correlated stereological and functional studies were performed on the effect of massive ACTH doses on adrenal cortex of the female hamster. ACTH resulted in a marked increase in adrenal gland weight at day 6 of treatment followed by a drop at day 9. Stereology showed significant enlargement of the zona fasciculata (ZF) cells with the highest value at day 6 and subsequent drop at day 9 of treatment. This hypertrophy was due to a notable increase in the volume of mitochondrial, SER, Golgi apparatus and lipid droplet compartments. Cortisol secretion by adrenal slices and homogenates was also highest at day 6 of ACTH administration and notably lower at day 9. At day 6 of ACTH treatment in outer ZF thrombi were seen. In their vicinity the subendothelial space was dilated and endothelial cells dissociated from the basal lamina. Numerous erythrocytes were also visible among dissociated ZF cells. At day 9 of experiment in outer part of ZF numerous spaces devoid of parenchymal cells appeared. The earlier authors considered the "empty spaces" or "holes" in hyperstimulated adrenal cortex as a sign of holocrine secretion of steroid hormones. The present findings enable us to introduce a new hypothesis on the development of these spaces. In our opinion in hyperstimulated adrenal cortex numerous thrombi may be formed leading thus to the degeneration of adrenocortical cells. Thus, the appearance of the "empty spaces" or "holes" in the gland is not connected with the holocrine secretion but with the regulation of the number of secretory cells in adrenal cortex by the thrombi-dependent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1991

Effects of the hypocholesterolemic drug, 4-aminopyrazolo (3,4-d) pyrimidine (4-APP), on the hamster adrenal cortex. An ultrastructural and functional study.

The aim of this study was to gain insight into the effects of 4-aminopyrazolo(3,4-d)pyrimidine (4-APP), a hypocholesterolemic drug, on the adrenal cortex of the hamster, representing an animal species in which steroidogenesis primarily relies on utilization of cholesterol synthesized de novo in the gland. 4-APP administration (1.5 mg/animal day for 3 days) to intact or dexamethasone-suppressed hamsters resulted in a marked proliferation of adrenocortical cells. However, the volume of parenchymal cells was unchanged in intact animals and lowered in the zona glomerulosa (ZG) and zona reticularis (ZR) of dexamethasone-administered hamsters. In both groups of animals, 4-APP strikingly increased the volume of the lipid-droplet compartment and markedly reduced the surface area of smooth endoplasmic reticulum in ZF cells, without significantly affecting the volume of the mitochondrial compartment and the surface area of mitochondrial cristae. These morphologic changes displayed no evident correlation with adrenal cortisol content and secretion. Since most of the 4-APP-induced changes were not prevented by dexamethasone, it seems legitimate to suggest that they could mainly depend on a direct effect of 4-APP on the hamster adrenocortical cells.

Adenine↗
PubMed1988

Autoradiographic studies on glucose utilization in individual zones of the rat thymus.

Wistar rats were injected intraperitoneally with 2-(14C)deoxyglucose and their thymuses were processed for thaw-mount autoradiography after 5, 10 or 35 min. Highest levels of radioactivity were demonstrated in the thymic medulla (5-fold higher than in the cortex). Scanning of autoradiograms for regional differences in grain densities indicated particularly intense glucose utilization in the cortico-medullary zone. Differences in glucose utilization between individual thymic zones seem to reflect differences in cellular composition, i.e., ratio of stroma cells to thymocytes.

Animals↗
PubMed1982

Analysis of colloidal gold methods for labelling proteins.

The relationship between unbound and bound proteins prepared during labelling with colloidal gold (Au) was investigated. For this aim, labelled 125I-bovine serum albumin and 125I-rabbit immunoglobulin were employed. The procedures associated with the washing of the Au labelled proteins (i.e. albumin) had a marked influence on the dissociation of the bound ligand. This was most evident when the concentration of albumin that was used for labelling was too high (0.1 or 1.0 mg/ml Au sol). We suggest that purification of labelled proteins be conducted shortly before use so as to avoid a significant amount of dissociation during the time when the solution is coming to equilibrium.

Animals↗
PubMed1981

The fine structure of the neural lobe of the mouse after transplantation under the kidney capsule.

The neurohypophysis of donor mice was implanted under the renal capsule of the recipients. The pituicytes survived while the neurosecretory axons disappeared. The ultrastructure of the glial cells was observed seven and nine weeks after transplantation. There were no signs of phagocytotic activity although remnants of axons were still present at seven weeks. The numerous processes of the pituicytes form a network with intercellular spaces wide in younger and narrower in older implants. The cells are connected by desmosomes and gap junctions. Pituicytes as well as blood vessels preserve their organotypic appearance. The transplant thus represents as experimental model for investigations on pituicytes in vivo in the absence of neurosecretory axons.

Animals↗
PubMed1978

Concanavalin A binding sites on the luminal surface of ependymal cells of third ventricle.

Detection of the Concanavalin A binding sites within the luminal surface of ependymal cells of the third ventricle has been accomplished using perfusion techniques as a way of exposing the cells to reaction solutions. Parameters for this procedure were established. It was found that electron dense reaction products form a layer ranging from 25--40 nm in thickness on the luminal surface of investigated cells. The microvilli exhibited a slightly thiner layer, the reaction products formed small patches on cilia.

Animals↗
PubMed1978

Intranuclear microfilament bundles in the ependymal cells of the third ventricle of the rat.

Intranuclear microfilament bundles were observed in ependymal cells of the third ventricle of the rat. The appeared as single, cylindrically-shaped fibrillar bands up to 4.9 micrometer in length. In cross sections of bundles, the microfilaments exhibited an apparently regular arrangement. They were separated by a distance of 4 to 5 nm, measuring approximately 11 nm from centre to centre. One bundle consisted of 55 to 88 microfilaments. The intranuclear bundles terminated at the inner membrane of the nucleus. They exhibited close spatial relationship to perinuclear chromatin, chromatin centres, intrachromatin granules and fibrillar structures. The average ratio of nuclear sections with and without bundles was 1:15.

Animals↗