Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cytochemical Effects”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1992

Effects of the prostanoid receptor antagonist, di-4-phloretin phosphate, upon human sperm motility.

The inhibitory effects of the prostanoid receptor antagonist, di-4-phloretin phosphate (DPP), upon washed human sperm motility were determined in vitro (up to 60 min of incubation). Concentrations tested were: 0.001, 0.01, 0.1, 0.25, 0.5, 2.5, 5.0 and 10.0 mM. All concentrations of DPP investigated caused cessation of sperm movement (percentage motility and average forward velocity) and the antimotility effect was essentially irreversible. The concentrations producing 50% inhibition were: percentage motility--1.31 +/- 0.56 mM (mean +/- SEM) and average forward velocity--1.95 +/- 0.68 mM. The mode of antimotility action appears to be multi-faceted. At high (10 mM) and intermediate (2.5 mM) concentrations, changes in fluidity of sperm plasmalemma (hypoosmotic swelling test) and loss of viability (nigrosin-eosin stain technique) constitute the primary means by which motility was disrupted. In contrast, these two parameters of motility remained unaltered at a lower concentration (0.25 mM) of DPP, and the mechanism precipitating the antimotility effect may involve mobilization of stored calcium ions and modulation of cyclic AMP levels.

Analysis of Variance↗
PubMed1992

Sodium-pump injury and arrhythmogenic transient depolarizations in catecholamine-induced cardiac hypertrophy.

The pathogenesis of arrhythmogenic transient depolarizations (TDs) was studied by means of electrophysiological and cytochemical methods in normal and hypertrophied left ventricular myocardium of the rat. In hypertrophy induced by administration of 5 mg/kg isoprenaline once daily for 7 days, the myocardial membrane was depolarized, the action potential duration was prolonged and the Vmax was decreased, as compared with those of age-matched normal controls. TDs induced by a train of action potentials could be observed in hypertrophied myocardium, but not in normal control myocardium. Ryanodine completely abolished TDs, but the beta-adrenoceptor agonist noradrenaline and the adenylate cyclase activator forskolin were without effect. In cytochemical studies, the Na+,K(+)-ATPase activity was localized in the sarcolemma, and three times as much reaction product, which appeared on the inner side of the cell membrane, was found in the normal myocardium than in the hypertrophied myocardium. The results suggest that catecholamine-induced cardiac hypertrophy damages the membrane-bound Na+,K(+)-ATPase and causes a cAMP-independent intracellular Ca overload and TDs, thereby permitting abnormal impulse formation, which predisposes the diseased myocardium to develop arrhythmias.

Action Potentials↗
PubMed1999

Single cell and tissue specific methods for evaluation of radiation and microgravity effects.

A discussion of different methods to evaluate dose/response and biological effects of ionizing radiation is given. Confocal scanning laser microscopy (CSLM) is presented as a high performing observation method for evaluating different cytological effects. Standard cytochemical techniques can be used to analyse the cell in situ with minimal disturbance of morphology and structure. If a relatively small number of cells are affected by the treatment, the use of confocal microscope observations is fast and has a better resolution than conventional fluorescence microscopy. The optical sectioning capability of the CSLM makes it possible to analyse stacks of cells on detectors up to a depth of 200 micrometer with a resolution of 0.7 micrometer. This is used to analyse single cell electrophoresis results and nuclear track analysis in poly allyl diglycol carbonate (PADC). Consecutive analysis of cells cultivated on PADC, and analysis of nuclear tracks after chemical etched tracks in the PADC, will make it possible to correlate physical dose with direct cellular effects. This is a promising method for single cell analysis and the study of the effects of ionizing radiation at low particle flux density.

Animals↗
PubMed1998

Morphological and functional features of endometrial decidualization following long-term intrauterine levonorgestrel delivery.

Irregular bleeding remains a common reason for the discontinuation of progestin-only contraception. The levonorgestrel releasing intrauterine system (LNG-IUS) has profound morphological effects upon the endometrium. Specific features are gland atrophy and extensive decidual transformation of the stroma. Morphological changes in the endometrium may be associated with perturbation of mechanisms regulating normal endometrial function. This study describes endometrial stromal and glandular features prior to and up to 12 months following insertion of the LNG-IUS. Comparison is made with first trimester decidua. In order to elucidate further mechanisms governing endometrial function with local intrauterine delivery of LNG, we here report histological features consistent with decidualization; a significant increase in granulocyte-macrophage colony stimulating factor (GM-CSF) immunoreactivity in decidualized stromal cells; glandular and stromal prolactin receptor expression and an infiltrate of CD56 + large granular lymphocytes and CD68 + macrophages. We are unaware of previous reports which have documented longitudinally both morphological and functional observations in endometrium exposed to local intrauterine levonorgestrel delivery. These studies demonstrate that long-term administration of intrauterine levonorgestrel results in features of altered morphology and function. No correlation was apparent between the end points in the study and the bleeding patterns described by the subjects. Further evaluation of these features in the context of menstrual bleeding experience may contribute to a better understanding of this troublesome side-effect which often leads to dissatisfaction and discontinuation of the intrauterine system.

Adult↗
PubMed1992

Catecholamine-induced cardiac hypertrophy uncouples beta-adrenoceptors from slow calcium channels.

Changes in the parameters of Ca(2+)-dependent slow action potentials (APs) and in their sensitivity to noradrenaline, forskolin, dibutyryl-cAMP and extracellular Ca2+ concentration were studied and compared in left ventricular trabeculae from normal control rats and rats with cardiac hypertrophy. Cytochemical studies were also carried out to determine changes in the activity of membrane-bound adenylate cyclase. Hypertrophy was induced by administration of 5 mg/kg isoproterenol once daily for 7 days. In hypertrophied cardiac muscle, the overshoot of the slow APs was increased by 75%, the maximum rate of rise (Vmax) increased by 76% and the AP duration at 50% repolarization (APD50) prolonged by 56%. The Vmax, an indicator of the slow inward Ca2+ current, increased, in a dose-dependent manner, in response to the beta-adrenoceptor agonist noradrenaline, the adenylate cyclase activator forskolin, the protein kinase activator cAMP and elevated Ca2+ concentration in normal control preparations, whereas in hypertrophied myocardium, the beta-agonist noradrenaline and the adenylate cyclase activator forskolin had no effect. In cytochemical studies with ATP as substrate, adenylate cyclase activity was localized in the sarcolemma, and significantly fewer reaction products appeared on the outer side of the cell membrane in hypertrophied myocytes than in control myocytes. The results suggest that catecholamine-induced cardiac hypertrophy damages the catalytic subunit of membrane-bound adenylate cyclase, thus uncoupling beta-adrenoceptors from slow Ca2+ channels in the transmembrane signalling process.

Action Potentials↗
PubMed1985

Cytotoxic effects of gossypol and vitamin E on human and rat lymphocytes and spermatozoa.

The cytotoxicity of vitamin E, gossypol, and mixture of both was determined in lymphocytes and spermatozoa using different concentrations of the substances. The cellular viability was assessed by means of the trypan blue exclusion test at 0, 60, and 120 minutes. Spermatozoa exhibited a higher sensitivity to these compounds, which was proportional to the length of exposure and the dose.

Biology↗
PubMed1992

Cyclophosphamide, doxorubicin, dexamethasone and procarbazine: effect on seminal plasma sialyltransferase activity.

The influence of chemotherapy agents, doxorubicin (adriamycin), cyclophosphamide, procarbazine, and dexamethasone on the activity of sialyltransferase in human semen has been examined. Aliquots of 25 mcL semen were incubated for 2 hours with the above substances at concentrations ranging from 10 to 800 mcg/incubation mixture. The measurement of sialyltransferase activity was based on the incorporation of radioactive sialic acid from CMP (14) C sialic acid) into asialofetuin. Doxorubicin and cyclophosphamide, at the maximal concentration of 800 mcg/incubation mixture exhibited an inhibiting effect on sialyltransferase activity which accounted for 15.7 +or- 16% and 12.2 +or- 16%, respectively. The rate of inhibition following incubation with maximal doses of dexamethasone (400 mcg) was 25.3 +or- 13%, respectively. The rate of inhibition following incubation with maximal doses of dexamethasone (400 mcg) was 25.3 +or- 12%. Inhibition caused by procarbazine did not exceed 5%. Inhibition of sialyltransferase in human semen by the materials examined in this study can diminish the transfer of sialic acid, thus interfering with normal glycoprotein's and glycolipid's syntheses in semen and possibly also in other fluids and tissues.

Asia↗
PubMed1991

The effects of the antiprogesterone RU486 (Mifepristone) on an endometrial secretory glycan: an immunocytochemical study.

OBJECTIVE: To examine the effects of progesterone (P) receptor blockade by RU486 (Mifepristone; Roussel-Uclaf, Paris, France) on a secretory endometrial glycan recognized by monoclonal antibody D9B1. DESIGN: Retrospective comparison of endometrial biopsies from treated and untreated women from 2 to 8 days after the luteinizing peak (LH) peak. SETTING: Infertility clinic, Jessop Hospital for Women, Sheffield. PATIENTS: Twenty-two normal fertile women received the RU486. A control group of 44 normal fertile women were also assessed. INTERVENTIONS: RU486 was administered to 22 normal women during the first half of the luteal phase and an endometrial biopsy examined 3 days later. MAIN OUTCOME MEASURES: Immunohistochemistry was used to assess the production and secretion of the D9B1 epitope. RESULTS: When the drug was given 2 days after the LH peak, it prevented appearance of the epitope. When RU486 was administered 5 days after the LH peak, epitope already present in gland cells was subsequently secreted. CONCLUSIONS: These data suggest that production of the sialo-oligosaccharide is P-dependent, but secretion through established intracellular pathways is P-independent.

Adult↗
PubMed1993

Robert Feulgen Prize Lecture. Distribution and role of gap junctions in normal myocardium and human ischaemic heart disease.

In the heart, individual cardiac muscle cells are linked by gap junctions. These junctions form low resistance pathways along which the electrical impulse flows rapidly and repeatedly between all the cells of the myocardium, ensuring their synchronous contraction. To obtain probes for mapping the distribution of gap junctions in cardiac tissue, polyclonal antisera were raised to three synthetic peptides, each matching different cytoplasmically exposed portions of the sequence of connexin43, the major gap-junctional protein reported in the heart. The specificity of each antiserum for the peptide to which it was raised was established by dot blotting. New methods were developed for isolating enriched fractions of gap junctions from whole heart and from dissociated adult myocytes, in which detergent-treatment and raising the temperature (potentially damaging steps in previously described techniques) are avoided. Analysis of these fractions by SDS-polyacrylamide gel electrophoresis revealed major bands at 43 kDa (matching the molecular mass of connexin43) and at 70 kDa. Western blot experiments using our antisera indicated that both the 43-kDa and the 70-kDa bands represent cardiac gap-junctional proteins. Pre-embedding immunogold labelling of isolated gap junctions and post-embedding immunogold labelling of Lowicryl-embedded whole tissue demonstrated the specific binding of the antibodies to ultrastructurally defined gap junctions. One antiserum (raised to residues 131-142) was found to be particularly effective for cytochemical labelling. Using this antiserum for immunofluorescence labelling in combination with confocal scanning laser microscopy enabled highly sensitive detection and three-dimensional mapping of gap junctions through thick slices of cardiac tissue. By means of the serial optical sectioning ability of the confocal microscope, images of the entire gap junction population of complete en face-viewed disks were reconstructed. These reconstructions reveal the presence of large junctions arranged as a peripheral ring around the disk, with smaller junctions in an interior zone: an arrangement that may facilitate efficient intercellular transfer of current. By applying our immunolabelling techniques to tissue from hearts removed from transplant patients with advanced ischaemic heart disease, we have demonstrated that gap junction distribution between myocytes at the border zone of healed infarcts is markedly disordered. This abnormality may contribute to the genesis of reentrant arrhythmias in ischaemic heart disease.

Amino Acid Sequence↗
PubMed1992

The role of calcium, polyamines and centrosomes in the formation and organization of cleavage furrows in amphibian eggs.

Cleavage furrows of amphibian eggs exhibit characteristic morphological features: the presence of finger-like microvilli (MV) along their outer edges, the formation of furrow walls from new plasma membrane lacking MV, and the subsequent retrieval of this membrane during the infolding of the furrow. A similar structure can be induced, specifically, by certain cytoplasmic components such as centrosomes, polyamines and calcium. Their respective roles in the events associated with the furrowing process have been investigated by injecting these agents into nucleated and enucleated Pleurodeles eggs and evaluating their effects using cytochemical labelling of the egg surface with a biotin-streptavidin system. The injection of polyamines (spermine or spermidine) and in some cases, calcium into enucleated eggs provoked MV elongation and the appearance of newly formed, smooth plasma membrane. In these eggs, this membrane was not incorporated into the furrows, and as a consequence, the blastomeres did not actually separate. In contrast, the injection of centrosomes into enucleated eggs induced both the incorporation and internalization of new membrane, resulting in the formation of furrows and a true cellularization of the eggs, identical to the cleavage process observed in fertilized eggs. The present results provide further evidence that the establishment of the furrow depends on two complementary interacting systems: the contractile elements of the egg cortex which regulate the insertion of new membrane and the mitotic center which is essential for the invagination of the furrow.

Animals↗
PubMed1995

Natural killer cell activity is reduced in association with oral contraceptive use.

Oral contraceptive (OC) use has been associated with increased incidence of a number of infections, but the mechanisms behind these changes is unclear. The present study compared OC users and nonusers in natural killer (NK) cell activity, NK phenotype, and illness frequency. Subjects were 55 female medical students (19 OC users, 36 nonusers). Three blood samples were obtained, 1 mo apart. Natural cytotoxicity was tested with a 51Cr assay. Self reports of illness symptoms during the previous week were collected at each blood sampling. NK phenotype number was assessed by flow cytometry. Oral contraceptive users had lower natural cytotoxicity and increased frequency of sneezing, gastrointestinal distress, runny nose, sore throat, coughing, and total illness symptoms, relative to nonusers. No differences were found between OC users and nonusers in NK phenotype number. These findings support the hypothesis that differences between users and nonusers in infection rates might be due to alterations in NK activity.

Adult↗
PubMed1980

Scanning and transmission electron microscopy of material adherent to intrauterine contraceptive devices.

The material adherent to intrauterine contraceptive devices (IUCDs) has been studied by transmission and by scanning microscopy coupled with X-ray microprobe analysis. Inert (Lippes Loop D, Saf-T-Coil and Dalkon shield) and medicated (Copper 7 and Progestasert) IUCDs were removed for examination from uteri immediately after hysterectomy. The cellular material identified on the surface of all inert IUCDs consisted mainly of macrophages with some polymorphonuclear leucocytes, erythrocytes, a few platelets and fibrin fibres. Polymorphonuclear leucocytes were the principle cells on the copper devices. Larger numbers of cells were evident on the inert arms than on the active part of the Progestasert device. All the devices examined exhibited varying amounts of surface calcium deposition. The IUCDs which had been in utero for longer periods showed the greatest amount of calcium deposition. Although a less rapid calcium deposition appeared to occur on the Progestasert device, this deposition may influence the release of medications from IUCDs which are retained in utero for longer periods than one year.

Calcium↗