Biomedical subjects

J J Turek

Publications and source records attributed to J J Turek.

At least 37 records · Page 2Linked to original sources

PubMed1994

Dietary polyunsaturated fatty acid effects on immune cells of the porcine lung.

The effects of various dietary polyunsaturated fatty acids (PUFAs) on the function of immune cells of the porcine lung was studied. Groups of six pigs were fed diets containing 10.5% corn oil [CO; enriched in linoleic acid (18:2, n-6)], linseed oil (LO; enriched in alpha-linolenic acid (18:3, n-3)], menhaden oil (MO; enriched in eicosapentaenoic (20:5; n-3) and docosahexaenoic (22:6; n-3) acids], linseed + corn oil (1:1; LC), and menhaden + corn oil (1:1; MC) for 28-30 days. Basal levels of alveolar macrophage (m phi) tumor necrosis factor-alpha (TNF-alpha) production were higher (P < .05) for LC- and MC-fed pigs than for CO- and LO-fed pigs. Lipopolysaccharide (LPS)-stimulated LC and MC m phi s produced more TNF than m phi s from pigs fed CO, LO, and MO diets. Macrophages from pigs receiving the CO and LC diets had higher (P < .05) levels of leucine aminopeptidase than m phi s from the other dietary groups. Lipopolysaccharide did not increase m phi nitrite production over basal levels except in the MO diet group. However, LPS-stimulated m phi s from the CO, MO, and LC dietary groups produced more nitrite than m phi s from MC-fed pigs. Alveolar lymphocytes from pigs receiving the MC diet produced more T cell growth factors than LO and MO m phi s. Alveolar m phi s from the different dietary groups did not differ in their capacity for non-immune-mediated phagocytosis of fluorescent latex beads. These results indicate that dietary PUFAs can modulate some functions of porcine alveolar immune cells and that this may prove significant for host response to respiratory disease agents.

Animals↗

PubMed1993

Measurement of NK activity in effector cells purified from canine peripheral lymphocytes.

Natural killer (NK) cells spontaneously lyse a variety of tumor cells in vitro, and are believed to play an important role in host resistance to tumor growth and metastasis in vivo. As part of our work in comparative oncology, we have designed and validated a canine NK cell assay. Of several lymphocyte isolation techniques evaluated, sedimentation of whole blood through a two-step Ficoll/Hypaque gradient (sp. gr. 1.066/1.119) followed by plastic adherence of monocytes resulted in the most pure lymphocyte population (> 95% lymphocytes). Of four cell lines evaluated as targets in the NK assay, a canine thyroid adenocarcinoma (CTAC) cell line was determined to be most sensitive, and a lymphoblastoid (CT45-S) cell line was determined to be most resistant to NK lysis. A 15 h effector-target incubation period using these targets resulted in reproducible measurement of cell specific lytic activity. Passage of canine lymphocytes through nylon wool columns did not result in a significant increase in NK activity. A final sedimentation of purified lymphocytes through a 45/50% Percoll gradient concentrated NK activity into a single band of lymphocytes. Lymphocytes forming conjugates with CTAC target cells were 5.5-6.5 microns in diameter, and were characterized by a reniform nucleus and varying numbers of electron-dense cytoplasmic granules.

Animals↗

PubMed1993

Indomethacin-induced gastrointestinal ulcers in rats: effects of dietary fatty acids and endotoxin.

The purpose of this study was to determine how dietary n-3 and n-6 polyunsaturated fatty acids (PUFA) affected the gastrointestinal response to lipopolysaccharide (LPS) and indomethacin (INDO) in the rat. Rats were fed diets containing 12.5% linseed oil (LO-enriched in short-chain n-3 PUFA) or corn oil (CO-enriched in n-6 PUFA). After 30 days on the diets, rats were given one of three treatments 1:10 mg/kg O55:B5 Escherichia coli LPS intraperitoneally (i.p.), 2:25 mg/kg INDO subcutaneously (s.c.), 3: a combination of 10 mg/kg i.p. LPS and 25 mg/kg (s.c.) INDO given 30 min before LPS. 20 h after challenge, rats were given an intravenous injection of Monastral Blue B to stain ulcer areas in the gastrointestinal tract. Lipopolysaccharide did not result in any Monastral Blue B vascular leakage in the gastrointestinal tract. Rats on the LO diet had significantly increased stomach and intestinal ulcers compared to CO fed rats. When rats were challenged with LPS and INDO, the LPS almost completely eliminated small intestinal ulcers, but enhanced ulcer development in the stomach.

Animals↗

PubMed1993

Endocytosis of folate-protein conjugates: ultrastructural localization in KB cells.

It has been demonstrated that proteins covalently conjugated to folic acid may be taken up by cells via endocytosis after binding to a folate binding protein (FBP) in the cell membrane. The proteins taken up in this manner remain catalytically active and they may modify physiological processes occurring in the cytosol. Confocal fluorescence microscopy of KB cells incubated with FITC-bovine serum albumin-folic acid conjugates showed that after uptake, the conjugates resided in large vesicular structures. The purpose of the present study was to determine the subcellular localization of protein-folic acid conjugates in KB cells using folic acid-bovine serum albumin-colloidal gold (F-BSA-CG) as a tracer. F-BSA-CG conjugates were taken up via uncoated pits or caveolae, and resided primarily in multivesicular bodies (MVBs) and other tubular endosomes at early time points (15-60 min). At later time points (6 hours), conjugates were still contained in MVBs but some were also found in secondary lysosomes or free in the cytoplasm. Coincubation of KB cells with transferrin-colloidal gold (TF-CG) and F-BSA-CG resulted in colocalization of TF-CG and F-BSA-CG within endosomal elements at times later than 15 minutes, indicating that the caveolae-mediated F-BSA-CG endocytic pathway converged with a pathway utilized by clathrin-coated pits.

Biological Transport↗

PubMed1992

Experimental renal papillary necrosis in the Mongolian gerbil (Meriones unguiculatus).

Sequential light microscopic and ultrastructural examination of kidneys from male and light microscopic examination of female Mongolian gerbils given 250 mg 2-bromoethylamine hydrobromide (BEA)/kg body weight ip were performed. In addition, male Mongolian gerbils were treated with both BEA and ip injections of either water, dimethyl sulfoxide, piperonyl butoxide, or reserpine. Light microscopic renal lesions in male Mongolian gerbils progressed from congestion of the vasa recta of the proximal inner medulla at 6 hr post-treatment to total renal papillary necrosis (RPN) at 24 hr post-treatment. There was no sex difference in sensitivity to BEA. Ultrastructural alterations in male gerbils were restricted to the vasa recta. Vascular lesions of endothelial swelling and pericapillary edema in the vasa recta of the proximal inner medulla was observed 2 hr post-treatment and progressed to occlusion by platelets adherent to exposed basement membranes at 6 hr post-treatment. Diuresis induced by injections of saline and injections of dimethyl sulfoxide or piperonyl butoxide did not affect the development of BEA-induced RPN. Reserpine slowed the development of BEA-induced RPN by its vasodilatory effect on the renal vasculature, not by blocking the endothelial toxicity of BEA. RPN induced by BEA in the Mongolian gerbil is apparently an ischemic necrosis of the inner medulla that develops secondary to endothelial damage of the vasa recta.

Animals↗

PubMed1992

Ultrastructural changes in articular cartilages of immature beagle dogs dosed with difloxacin, a fluoroquinolone.

The ultrastructural features of quinolone-induced arthropathy were studied in the humeral and femoral heads of nine skeletally immature Beagle dogs (3 months old) that were dosed orally with difloxacin at 300 mg/kg body weight and euthanatized 24, 36, or 48 hours later in groups of three. Three age-matched dogs were given a placebo and euthanatized after 48 hours. Mitochondria in chondrocytes had significantly greater cross-sectional areas (P less than 0.05) in electron micrographs from dogs euthanatized after 48 hours of treatment than did those in other groups. There was also a significantly greater percentage of chondrocytes with swollen mitochondria in treated dogs than in the controls (P less than 0.05). These changes preceded the necrosis observed in some chondrocytes in the dogs of the 48-hour group. Disruption of extracellular matrix was first observed in the pericellular matrix of necrotic chondrocytes, indicating that this change was secondary to the changes in chondrocytes. Fissures within cartilages apparently resulted from the loss of the normal association of proteoglycans with collagen fibrils.

Administration, Oral↗

PubMed1992

Early sequential ultrastructural renal alterations induced by 2-bromoethylamine hydrobromide in the Swiss ICR mouse.

Thirty-two male Swiss ICR mice were injected intraperitoneally with 300 mg 2-bromoethylamine hydrobromide/kg body weight, anesthetized, and perfused with glutaraldehyde-paraformaldehyde solution at 5, 15, 30, 60, 90, 120, 150, and 180 minutes after treatment. Eight control mice were injected intraperitoneally with sterile diluent, and one was perfused at each of the same time periods as the treated mice. Proximal tubule epithelial alterations progressed over time from increased secondary lysosome and myeloid body formation to cellular and mitochondrial swelling and eventually cell necrosis. The glomerular, peritubular, and vasa recta capillaries had endothelial cell swelling and desquamation and platelet aggregation. Bromoethylamine nephrotoxicosis in the male Swiss ICR mouse is an ischemic necrosis of the proximal tubules and papilla initiated by endothelial cell damage and makes an excellent model of chemically induced damage to endothelial cells and tubular necrosis.

Animals↗

PubMed1991

The effect of dietary n-3 and n-6 fatty acids on tumor necrosis factor-alpha production and leucine aminopeptidase levels in rat peritoneal macrophages.

The purpose of this study was to determine the effect of dietary n-3 and n-6 fatty acids on tumor necrosis factor-alpha (TNF-alpha) production and macrophage (MO) activation state. Rats were fed diets containing 12.5% linseed oil (LO) or corn oil (CO) that are high in n-3 and n-6 fatty acids respectively. The LO diet resulted in a significant increase in basal and endotoxin (LPS)-induced levels of TNF-alpha from resident MO cultured in vitro. There was no difference between the diets in LPS-induced TNF-alpha production by complete Freund's adjuvant (CFA) elicited macrophages. Variable responses were also observed between LO and CO MO in response to prostaglandin E2, indomethacin (INDO), and the prostaglandin E receptor antagonist SC-19220. This may indicate differences in signal transducing secondary messengers due to different activation states, receptor expression or ligand binding. Fluorescence due to leucine aminopeptidase (LAP) staining was determined by flow cytometry. Resident LO MO had a 15% increase in LAP fluorescence compared to CO MO. In CFA-elicited MO, the CO MO had a 43% increase in fluorescence compared to LO MO. Resident LO MO increased in LAP fluorescence by 35% to the activated state whereas resident CO MO increased in LAP fluorescence by 93%. The smaller window of activation for the LO MO may explain some of the antiinflammatory properties of dietary n-3 fatty acids.

Animals↗

PubMed1991

Cytochemical studies of hydrogen peroxide generation in postischemic hepatocytes.

Reoxygenation injury that occurs when blood circulation is restored to previously ischemic tissues is currently discussed as a pathophysiological entity distinct from the primary anoxic injury that develops during ischemia per se. To test the hypothesis that reoxygenation injury in hepatocytes is caused by a postischemic burst of reactive oxygen species (ROS), including superoxide radicals, O2-., and hydrogen peroxide, H2O2, we performed a cytochemical study exploiting the peroxidase activity within peroxisomes as a sensitive ultrastructural detector of intracellular H2O2 generation. The osmiophilic polymer formed when tissue peroxidase is incubated with 3,3'-diaminobenzidine (DAB) and H2O2 was used as a marker for endogenous H2O2 in rat liver slices in short-term organ culture subjected to a cycle of 60-min ischemic anoxia and 30-min reoxygenation in the presence of DAB without exogenous H2O2. Peroxisomal reaction product was quantitatively evaluated in transmission electron micrographs of systematically sampled hepatocytes. Mean densities of positive peroxisomes per 1,000 micron2 (+/- SE) in liver slices subjected to various treatments were as follows: continuous anoxia (negative control) 0 +/- 0; normoxia + exogenous H2O2 (positive control) 45 +/- 12; normoxia only 26 +/- 2; ischemia-reoxygenation 13 +/- 6; ischemia-reoxygenation + xanthine oxidase inhibitor, oxypurinol 5 +/- 3; ischemia-reoxygenation + peroxidase inhibitor, aminotriazole 7 +/- 3. Endogenous H2O2 can be detected in hepatocytes by electron microscopic cytochemistry and may in part derive from xanthine oxidase, but it is not substantially increased in the postischemic state. We conclude that hepatocytes do not exhibit a postischemic burst of reactive oxygen species that could cause reoxygenation injury.

Amitrole↗

PubMed1991

Endothelial superoxide production in buffer perfused rat lungs, demonstrated by a new histochemical technique.

This paper describes a new approach to the histochemical demonstration of superoxide generation by pulmonary vascular endothelial cells using a supravital high manganese/diamine technique, in which nascent superoxide radicals induce formation of amber, osmiophilic polymers of diaminobenzidine (DAB), detectable by light or electron microscopy. Superoxide oxidizes Mn2+ ions to the Mn3+ valence state. In turn trivalent manganese readily initiates formation of the polymerized DAB reaction product. Isolated rat lungs were perfused in situ with bloodless, buffered high manganese/DAB salt solution via the pulmonary artery. The aortic root was ligated to minimize outflow from the left heart, so that perfusate shunted across pulmonary capillary endothelium, to fill the alveolar spaces and drain via the trachea. Lungs were perfused for 3 min with oxygen equilibrated buffer, with or without 60 min prior warm anoxia, induced by initial perfusion with argon sparged buffer. After aldehyde fixation and tissue processing DAB reaction product was detected on the inner, luminal surface of the vascular endothelium by both light and electron microscopy. Bronchi and epithelial cells never stained positively. The histochemical reaction was absent or markedly reduced in non-manganese treated or superoxide dismutase treated lungs, as well as in lungs perfused with calcium free buffer. The histochemical reaction was not prevented by the xanthine oxidase inhibitors allopurinol or methylene blue. The high manganese/diamine technique provides direct visual evidence of a calcium dependent mechanism by which pulmonary vascular endothelial cells can generate superoxide radicals.

Animals↗

PubMed1991

Endothelial superoxide production in the isolated rat heart during early reperfusion after ischemia. A histochemical study.

This paper describes a histochemical study of superoxide generation in buffer-perfused, isolated rat hearts during the first 2 minutes of reperfusion after 60 minutes of warm ischemia. Superoxide radical production was demonstrated by a modification of Karnovsky's manganese/diaminobenzidine technique, in which superoxide oxidizes Mn++ to Mn ions, which in turn oxidize diaminobenzidine to form amber, osmiophilic polymers, observable by light or electron microscopy. Isolated hearts were rendered ischemic, reperfused with oxygen equilibrated buffer containing Mn++ and diaminobenzidine, fixed by perfusion with Trump's solution, and processed for light and electron microscopy. The method consistently demonstrated evidence of superoxide generation near the luminal surfaces of arterial, capillary, and venular endothelial cells during the first 2 minutes of reoxygenation after ischemia. The histochemical reaction was absent or markedly reduced in non-manganese-treated or nonischemic hearts, as well as in hearts perfused with calcium-free or oxygen-free buffers. The histochemical differences were statistically significant on quantitative morphometric analysis. These results provide direct, visual evidence of the existence and endothelial localization of a burst of superoxide radicals in intact, postischemic myocardium and suggest the pathophysiologic importance of calcium-dependent endothelial cell activation in the initiation of reperfusion injury.

3,3'-Diaminobenzidine↗

PubMed1990

Cyanide-induced neurotoxicity: calcium mediation of morphological changes in neuronal cells.

Calcium channel blockade decreases the elevation of brain calcium as well as the tremors produced by cyanide in mice. To determine if cyanide-induced morphological changes could also be inhibited by calcium channel blockade, the effect of diltiazem was studied in cultured rat pheochromocytoma (PC12) cells, a neuronal model. Incubation with KCN (1 to 10 mM for 1 to 2 hr) caused depletion of secretory granules, alignment of remaining granules along the plasma membrane, and mitochondrial swelling. All these effects were inhibited by pretreatment with 0.01 mM diltiazem. Scanning electron microscopy revealed that cyanide (1 to 10 mM for 1 to 2 hr) produced loss of microvilli and bleb formation in PC12 cells. These changes were partially inhibited by preincubation with 0.01 mM diltiazem. Incubation of cells with 10 mM cyanide increased release of lactic dehydrogenase (LDH) into the culture media at 60 and 120 min. A decrease in cell viability, as determined by trypan blue dye exclusion, paralleled the release of LDH. At 120 min of cyanide incubation, 24% of the cells excluded dye. Both the release of LDH and decreased cell viability were attenuated by pretreatment with diltiazem. The results indicate that the influx of extracellular calcium is an important factor mediating cyanide-induced morphologic changes in neuronal cells.

Animals↗

PubMed1989

Naturally occurring mucocutaneous histoplasmosis in a rabbit.

Mucocutaneous histoplasmosis was diagnosed in a pet rabbit. A mass protruding through the anal opening was histologically composed of a densely cellular infiltrate of macrophages which expanded the anorectal submucosa. Macrophages contained abundant yeast forms of fungi morphologically consistent with Histoplasma capsulatum. Infection appeared to be localized. Histoplasmosis should be considered in the differential diagnosis of granulomatous inflammatory disease in the rabbit.

Animals↗

PubMed1989

Scanning electron microscopy of sarcoptic mange lesions in swine.

Scanning electron microscopy revealed that lesions of sarcoptic mange in swine, pass through 3 different stages. During the first 3 weeks of infestation, adult female mites tunnel into the epidermis. During the following 3 or 4 weeks, the surface openings of these tunnels become covered with keratinized epidermal crust which increases in thickness. After 7 weeks of infestation, the crust falls off, the tunnel openings become apparent again and most of the mites vacate these tunnels.

Animals↗

PubMed1989

Etiologic studies on late-term swine abortions.

One hundred thirty-eight swine abortions were studied in detail in an effort to identify an etiologic agent. A viral agent was implicated in 7 cases. Bacteria were isolated in less than half of the examined cases: however, in 61% of the cases, motile, filamentous organisms were observed in tissues and fluids. Although swine sera from farms experiencing reproductive problems had a high reactor rate to Leptospira bratislava antigen, electron microscopy of the observed organism revealed a wall-free prokaryote morphologically typical of the class Mollicutes.

Abortion, Veterinary↗

PubMed1989

Effect of zearalenone on the growth of mouse embryos from blastocysts to the egg cylinder stage in vitro.

Embryos were harvested at the blastocyst stage from nontreated outbred mice and were grown in vitro for 4 days. Embryos cultured in control medium hatched and grew to the egg cylinder stage. Purified zearalenone (ZEN) added to the culture medium at concentrations of 8.5 to 68 micrograms/ml decreased the number of embryos growing, with a 50% decrease in the number growing in 32 micrograms of ZEN/ml of medium. Embryos growing in ZEN had decreased numbers of cells derived from the inner cell mass, normal growth of the trophoblast, less cellular differentiation than was seen in control embryos, and increased numbers of phagosomes. Undifferentiated cells of the inner cell mass of control and treated embryos were of the same size, as determined by morphometric analysis. Addition of 25 micrograms of estradiol/ml of culture medium caused no decrease in number of embryos growing or in embryonic size. Saturation of culture medium with ZEN (68 micrograms/ml) did not inhibit the growth of a tissue culture line of goat synovial cells. Seemingly, ZEN at concentrations near saturation inhibited the growth of mouse embryos in vitro. This effect was not duplicated with similar concentrations of estradiol and was not manifested in culture-adapted cells.

Animals↗

PubMed1989

Lectin binding to small intestinal goblet cells of newborn, suckling, and weaned pigs.

Lectin binding of small intestinal goblet cells was examined in newborn, suckling, and weaned pigs. Sections of duodenum, proximal portion of the jejunum, distal portion of the jejunum, and ileum were embedded in a hydrophilic acrylic resin and treated with each of the following lectins: Canavalia ensiformis, Ricinus communis I, Glycine max, Ulex europaeus I, and Triticum vulgaris. Percentages of goblet cells binding each lectin were calculated within intestinal regions. Differences in lectin-binding affinity were detected among pigs of various ages and among various intestinal regions within pig age groups.

Animals↗

PubMed1988

Hemodynamics, plasma eicosanoid concentrations, and plasma biochemical changes in calves given multiple injections of Escherichia coli endotoxin.

Twelve male neonatal calves (39 to 50 kg) were allotted to 3 groups of 4 calves each. All calves were anesthetized with halothane, and then Escherichia coli endotoxin was given intravenously (3 times) and intraperitoneally (3 times) during a 6-hour period. Group-1 calves were untreated, group-2 calves were pretreated with a low dose of flunixin meglumine (1.1 mg/kg of body weight), and group-3 calves were pretreated with a high dose of flunixin meglumine (4.4 mg/kg). In calves of group 1, the mean systemic arterial blood pressure (MABP) and cardiac output (CO) decreased, but pulmonary arterial pressure increased after the initial intravenous and intraperitoneal injections of endotoxin. In calves of this group, these changes were accompanied by increased plasma thromboxane B2 (TxB2) concentration. During this period, increased plasma TxB2 concentration or hemodynamic changes were not detected in calves of groups 2 and 3. Only calves of group 1 had altered hemodynamics early in the experiment; however, after 6 hours, calves of all 3 groups had similarly decreased CO and MABP. In calves of the untreated group, plasma 6-keto-prostaglandin (PG)F1 alpha concentration increased steadily from the beginning of the experiment until 3 hours later. The CO and MABP were low at the time when serum 6-keto-PGF1 alpha concentration was high; however, these 2 measurements also were low in treated calves who did not have correspondingly high plasma 6-keto-PGF1 alpha concentration. Regional blood flow analysis did not reveal correlations between prostanoid concentrations and altered blood flow to selected tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗