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PubMed2005

Magnetic resonance image-guided trans-septal puncture in a swine heart.

PURPOSE: To test the feasibility of performing magnetic resonance (MR)-guided trans-septal punctures in the swine heart. MATERIALS AND METHODS: All procedures were performed in a 1.5-T MR scanner. A novel, active MR intravascular needle system was utilized for needle tracking and septal punctures. Trans-septal punctures were performed in five swine using electrocardiogram (ECG)-gated high resolution and non-ECG-gated, real-time MR imaging techniques. The intravascular needle was advanced over a guidewire from the femoral vein. Once the needle was in proper position, trans-septal punctures were made. RESULTS: Active tracking of the needle traversing the septum was possible. The location of the catheter tip was confirmed using real time gradient recalled echo (GRE). After a confirmatory ventriculogram with gadolinium-DTPA, a 0.014-inch guidewire was advanced into the left atrium and left ventricle. All punctures were made with no change in cardiac rhythm or rate; postmortem analysis was performed on all animals and demonstrated that 18/19 (95%) punctures were directly through the fossa ovalis. CONCLUSION: Using only MR guidance and a novel active intravascular needle system, we were able to repeatedly puncture the fossa ovalis in a swine heart from a transfemoral approach, with direct visualization of all components, including the needle, the atria, the fossa ovalis, and the surrounding vasculature.

Animals↗
PubMed1999

Masking and reduction of the Galactose-alpha1,3-Galactose (alpha-Gal) epitope, the major xenoantigen in swine, by the glycosyltransferase gene transfection.

The alpha-Gal epitope (Gal-alpha1-3Gal-beta1-4-GlcNAc-R), which is biosynthesized by the UDP-Gal:alpha1-3-galactosyltransferase (alpha1, 3GT), is highly associated with hyperacute rejection in swine to human xenotransplantation. A variety of strategies have been pursued to reduce or eliminate this epitope from swine tissues. Since swine ES cells are not available at present, the targeted knock out of the alpha1,3GT is restricted. Other strategies, such as enzyme competition of the alpha1,3GT with other glycosyltransferases and/or control of sugar processing by the glycosyltransferases, provide a new insight into the downregulation of the alpha-Gal epitope. This review will focus on this type of strategy, which involves a gene transfection of variety of glycosyltransferases as competitors against alpha1,3GT.

Animals↗
PubMed1993

Exponential relationship between plasma cholesterol levels and atherosclerotic lesion size in hyperlipidemic swine.

The effect of fish oil supplements on atherogenesis is controversial, especially when fish oil does not lower plasma cholesterol. Some studies in swine have shown that a fish oil supplement to a butter-cholesterol diet reduces atherogenesis. The fish oil supplement also frequently reduces average plasma cholesterol levels. The reduction in lesion size has been shown to be greater than can be expected from average plasma cholesterol reductions, if a linear relationship between lesion size and plasma cholesterol was assumed. However, in an experiment in which we equalized time-weighted average plasma cholesterol levels, there was no significant reduction in lesion size in the fish oil supplemented group. This led us to question the validity of the linear relationship between lesion size and plasma cholesterol level. In this study we have combined the results of eight study blocks with a total of 76 swine fed a similar hyperlipidemic, butter-cholesterol diet. Of these, 24 received a fish oil supplement (BT+fish oil) and 52 swine received no fish oil supplement (BT). The average lesion size as measured by nuclear profiles per cross section of a fixed site in the abdominal aorta (ABNpCx) was 7704 +/- 778 (mean +/- SEM) for the BT group and 2360 +/- 1145 for the BT+fish oil group. Total plasma cholesterol levels were measured at the outset and at monthly intervals until sacrifice. For each animal we obtained a time-weighted average based on the trapezoidal rule.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

African swine fever virus guanylyltransferase.

The gene coding for the guanylyltransferase of African swine fever virus has been identified and sequenced. The gene, designated NP868R, is located within fragments EcoRI N' and D of the virus genome (BA71V strain) and encodes a protein with a predicted molecular mass of 99.9 kDa that shares significant similarity with the large subunit of both vaccinia and Shope fibroma virus capping enzymes, with percentages of identity of 20.6 and 21.8%, respectively. A protein of 95 kDa was induced in Escherichia coli cells transformed with a recombinant plasmid carrying the NP868R gene. The E. coli expressed protein, as well as a protein of the same molecular weight present in African swine fever virus particles, form a covalent complex with GTP that can be reversed by pyrophosphate, two characteristic reactions of guanylyltransferases. An examination of the amino acid sequences of the African swine fever virus, poxvirus, and yeast guanylyltransferases has revealed a common motif around a lysine residue at the amino-terminal part of the proteins [Y(V, A)X2K(T, A)DG] which resembles the adenylylation site of DNA ligases (Tomkinson, A. E., Totty, N. F., Ginsburg, M., and Lindahl, T. (1991). Proc. Natl. Acad. Sci. USA 88, 400-404). This lysine residue could be the guanylylation site in these enzymes.

African Swine Fever Virus↗
PubMed1994

An African swine fever virus gene with similarity to the T-lymphocyte surface antigen CD2 mediates hemadsorption.

An open reading frame, LMW8-DR, in the African swine fever virus (ASFV) genome possesses striking similarity to the lymphocyte membrane antigen CD2. All characterized CD2 domains, including the amino-terminal signal sequence, IgV, hinge, IgC2, stalk, transmembrane, and proline-rich carboxy cytoplasmic domains, are highly conserved in the ASFV gene. Critical residues for the binding of the lymphocyte function-associated antigen (LFA-3) and CD59 and for T-cell activation are also partially conserved. LMW8-DR is actively transcribed in ASFV-infected swine macrophages and Vero cells at late times in the infection cycle and Vero and COS cells transiently expressing the LMW8-DR open reading frame hemadsorbed swine red blood cells. The structural and functional similarities of LMW8-DR to CD2, a protein that is involved in cell-cell adhesion and immune response modulation, suggest a possible role in the pathogenesis of ASFV infection.

African Swine Fever Virus↗
PubMed1993

Coenzyme Q10 protects ischemic myocardium in an open-chest swine model.

Myocardial stunning, defined as a reversible decrease in contractility after ischemia and reperfusion, may be a manifestation of reperfusion injury caused by free oxygen radical damage. The aim of this study was to test the hypothesis that pretreatment with coenzyme Q10 (ubiquinone), believed to act as a free radical scavenger, reduces myocardial stunning in a porcine model. Twelve swine were randomized to receive either oral supplementation with coenzyme Q10 or placebo for 20 days. A normothermic open-chest model was used with short occlusion (8 min) of the distal left descending coronary artery followed by reperfusion. Regional contractile function was measured with epicardial Doppler crystals in ischemic and nonischemic segments by measuring thickening fraction of the left ventricular wall during systole. Stunning time was defined as the elapsed time of reduced contractility until return to baseline. Coenzyme Q10 concentrations were measured in blood and homogenized myocardial tissue by high performance liquid chromatography. Plasma levels of reduced coenzyme Q10 (ubiquinol) were higher in swine pretreated with the experimental medication as compared to placebo (mean 0.45 mg/l versus 0.11 mg/l, respectively). Myocardial tissue concentrations, however, did not show any changes (mean 0.79 micrograms/mg dry weight versus 0.74 micrograms/mg). Stunning time was significantly reduced in coenzyme Q10 pretreated animals (13.7 +/- 7.7 min versus 32.8 +/- 3.1 min, P < 0.01). In conclusion, chronic pretreatment with coenzyme Q10 protects ischemic myocardium in an open-chest swine model. The beneficial effect of coenzyme Q10 on myocardial stunning may be due to protection from free radical mediated reperfusion injury. This protective effect seems to be generated by a humoral rather than intracellular mechanism.

Animals↗
PubMed1994

Characterization of six new loci within the swine major histocompatibility complex class III region.

A search for new potential coding sequences was conducted within two overlapping cosmid genomic DNA clusters of about 170 and 45 kb from the swine major histocompatibility complex class III region. The sequences were detected with various probes, including pools of swine cDNA, homologous and heterologous genomic sequences, and synthetic oligonucleotides. The 170 kb cluster was centered on the tumor necrosis factor genes (TNF), and the 45 kb cluster contained the heat-shock protein 70 genes (HSP70). The TNF cluster revealed the presence of five new genes: lymphotoxin beta, BAT1, BAT2, BAT3, and a sequence related to DNA-binding factors. No sequence homologous to B144 was found in the TNF cluster, although other unidentified coding sequences may be present in this cluster. The HSP70 cluster contained a gene identified as BAT6, that is, tRNA-valyl synthetase. These results provide new evidence that the genomic maps of these various genes in the TNF and HSP70 sub-regions are similar in swine and human.

Animals↗
PubMed1993

Swine as a model of skin inflammation. Phospholipase A2-induced inflammation.

A predictive animal model of skin inflammation is needed for the development of potential therapeutic agents. The existing models of inflammation rely on animals whose skin physiology or biochemistry differs significantly from human. The objective of this investigation was to evaluate the swine as a potential model of inflammation, because its skin has been recognized to exhibit morphologic and functional similarities to human skin. In the swine, an inflammatory response was produced following intradermal injection of snake venom phospholipase A2 (PLA2). This response was characterized by transient erythema (2-3 h) and microscopic changes of cell infiltration, epidermal hyperplasia, and dermal damage, which were apparent two days after PLA2 and peaked by day 7. In general, these microscopic changes persisted up to 21 days. Treatment with the antiinflammatory steroid, betamethasone dipropionate (Diprolene), gave a significant reduction of the inflammatory responses. Heat-inactivated PLA2, ovalbumin, or saline did not provoke this reaction, although PLA2 inactivated by bromophenacyl bromide alkylation did produce an inflammatory response. The alkylated PLA2 was also able to provoke an inflammatory response in the mouse paw edema assay. These results demonstrate that PLA2 can stimulate an inflammatory response in the swine skin, but that phospholipid hydrolytic activity is not required.

Administration, Topical↗
PubMed1992

Resistance to stretch, [Ca2+]i, and activation of swine arterial smooth muscle.

Rapid stretching of smooth muscle induces a large increase in stress (resistance to stretch), and stress gradually decreases to intermediate values (stress relaxation). This study elucidated whether [Ca2+]-dependent crossbridge activation or passive mechanical structures were responsible for resistance to stretch and stress relaxation in swine carotid media, a tissue that does not exhibit a myogenic response. Tissues were equilibrated at the optimal length for stress development (L0) and loaded with aequorin to estimate myoplasmic [Ca2+]. In tissues activated with contractile agonists, both resistance to stretch and the rate of stress relaxation appeared to correlate best with the stress present before stretch. Stretch-induced [Ca2+] transients had no major role in determining resistance to stretch or stress relaxation. In the unstimulated swine carotid, resistance to stretch was only slightly reduced and stress relaxation not affected by removal of extracellular Ca2+, suggesting that resistance to stretch and the rate of stress relaxation in unstimulated tissues was predominantly dependent on the passive components of smooth muscle rather than attached, Ca(2+)-dependent crossbridges. Incubation of tissues with tetraethylammonium ion had no measurable effect on stretch-induced [Ca2+] transients but increased resistance to stretch, suggesting that stretch-induced myogenic contractions may be mediated by an increase in the sensitivity of the contractile apparatus to [Ca2+]. Despite the ability of stretch to produce substantial increases in myoplasmic [Ca2+], the contractile apparatus of swine carotid is quite insensitive to the stretch-induced [Ca2+] elevations.

Animals↗
PubMed1977

Tissue distribution of PCB components in swine and sheep fed three different rations containing Aroclors 1242 and 1254.

Growing swine and sheep were fed three dietary variations containing 20 ppm of Aroclors 1242 or 1254 for 13 to 15 weeks. Generally, Aroclor 1254 residues were higher; higher 1242 residues in swine blood, spleen, and ovary are attributed to persistent major components of this Aroclors. Some minor differences in total PCB were observed with varying diets, but peak composition did not vary. Some lower chlorinated components maintained higher levels in the blood relative to other components; other components were selectively accumulated in tissues such as fat and muscle. Blood and fat residues in sheep declined during the last weeks of feeding. Microsomal oxidase levels were elevated in response to PCB and diet in both species, but the response was greater in sheep. Sheep liver microsomes were capable of metabolizing pure analogs and components of Aroclor 1242. Major differences in Aroclor profiles can be demonstrated between swine and sheep residues and total residues can be estimated by measuring selected peaks in blood and backfat. The peaks which provide the most reliable estimate of total PCB residue vary with species and Aroclor.

Animal Feed↗
PubMed1985

A rapid sample preparation method for the determination of sulfamethazine in swine tissues by high-performance liquid chromatography.

A rapid procedure for the determination of sulfamethazine in swine muscle and kidney is described. The method comprises sonication-aided extraction with dichloromethane, cleaning-up of the extract on a combination of silica and reversed-phase C18 Sep-Pak cartridges and analysis by high-performance liquid chromatography on a Hypersil ODS column using acetonitrile/ammonium acetate solution (10 mmol X 1(-1), pH 6.8) 1 + 3 v/v as the mobile phase. Detection was performed at 254 nm. Mean recoveries of added sulfamethazine from swine muscle and kidney, at levels of 0.05 to 0.5 micrograms X g-1, were 89.5 and 80.5%, respectively. After intramuscular injection of sulfamethazine into swine, residues in tissues were also determined. The application of ultrasonic energy for the extraction of sulfamethazine residues from animal tissues is also discussed.

Animals↗
PubMed1999

Effects of diaspirin crosslinked hemoglobin infusion in treadmill-exercised swine.

The hemodynamic and metabolic effects of diaspirin crosslinked hemoglobin (DCLHb) were investigated using graded treadmill exercise in swine (n = 5/group). Swine received DCLHb (10% solution, 5 ml/kg) or oncotically-matched human serum albumin (HSA, 5ml/kg). Baseline metabolic and hemodynamic data were similar. In both groups exercise increased hemodynamic parameters. Exercise increased heart rate (HR) from 139 +/- 12 to 293 +/- 28 bpm with DCLHb and from 136 +/- 13 to 314 +/- 13 bpm with HSA. Exercise increased cardiac output (CO) from 5.7 +/- 0.75 to 15.6 +/- 2.01/min in the DCLHb group and from 5.3 +/- 0.48 to 15.7 +/- 0.881/min in the HSA group. However, CO returned to baseline faster with DCLHb upon stopping exercise. The DCLHb-treated group demonstrated a significantly higher oxygen extraction during exercise (12.04 +/- 0.38 vs 9.48 +/- 0.99 ml O2/100 ml blood) and a lower oxygen delivery throughout recovery (74.6 +/- 6.6 vs 102.2 +/- 7.21 O2/min), indicating enhanced oxygen delivery during exercise in the treatment group. DCLHb infusion did not impair metabolic or hemodynamic functions. These data indicate that DCLHb may increase oxygen delivery to working tissue more efficiently than HSA during treadmill exercise in swine.

Animals↗
PubMed1976

Cholesterol and fatty acid synthesis in swine.

In incubation studies with swine tissue slices, acetate-1-14C or glucose-U-14C as substrates were incorporated more readily into fatty acids and cholesterol in adipose tissue than other tissues tested. Cholesterol and fatty acid synthesizing acitivity was substantial in the small intestine. When acetate was available, liver, small intestine, and adipose tissue were important sites for cholesterol synthesis. Heart and aortic tissue had marginal levels of cholesterol synthesizing ability. Lipogenesis in adult swine liver, heart, and aortic tissue was extremely low. As in tissue slices, incorporation of acetyl-1-14C CoA into fatty acids by adipose homogenates indicated high lipogenic activity. Subcellular fractionations of heart and aortic tissue indicated that the heart microsomal fraction had the highest lipogenic activity as measured by the incroporation of acetyl-4-14C CoA into fatty acids. In adult swine adipose tissue, the incorporation of glucose-U-14C into fatty acid was higher than its incorporation into glyceride-glycerol. The synthesis of glyceride-glycerol from glucose-U-14C or acetate-1-14C in liver was higher than for fatty acid synthesis. The acitivity of acetyl CoA carboxylase, fatty acid synthetase, citrate cleavage enzyme, nicotinamide adenine dinucleotide phosphat-malate dehydrogenase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase was considerably higher in adipose tissue than in other tissues tested, paralleling its high lipogenic capacity.

ATP Citrate (pro-S)-Lyase↗
PubMed1984

Regulation of the synthesis of mucin glycoproteins in swine trachea explants.

Swine tracheal epithelium has been cultured as explants in a chemically defined medium for periods of up to 2 wk. The viability of the explants was shown by the preservation of the ultrastructural features of cells in the epithelial layer and by the active incorporation of radioactive glucosamine and sulfate into secreted mucin glycoproteins. The rate of secretion of mucin glycoprotein was about 0.035 mg per cm2 per d. After initial 24 h lag period was shown to be due to the equilibration of intracellular mucin glycoprotein pools with radioactive precursors. The rate of secretion of glycoprotein showed a linear dependence on the area of the explant, and maximal incorporation was observed at 200 microM glucosamine. A higher concentration of 35SO4, 1000 microM, was required for maximal incorporation of the precursor. Insulin at 0.1 to 1 microgram/ml increased the rate of secretion twofold, whereas 0.1 to 100 micrograms/ml of hydrocortisone and 0.1 to 100 micrograms/ml of epinephrine significantly decreased the rate of secretion. Vitamin A had little or no effect of normal trachea explants at low concentrations, and, at higher concentrations, 10(-5) M, it decreased the secretion of mucin glycoproteins. Vitamin A, at a concentration of 10(-9) M, increased the rate of synthesis of glycoprotein at least fourfold in trachea explants from vitamin A-deficient rats. Mucus secretions collected from the surface of swine trachea and from the culture medium of trachea explants were purified. The mucus was solubilized by reduction and carboxymethylation, and the high molecular weight mucin glycoproteins were purified by chromatography on Sepharose CL-6B columns under dissociating conditions in 2 M guanidine HCl. The mucin glycoproteins purified from swine trachea and from the culture medium of trachea explants were virtually indistinguishable. They showed the same properties when examined by gel electrophoresis and immunoprecipitation. The purified glycoproteins contained about 25% protein, and serine, threonine, and proline were the principal amino acids present. More than 80% of the carbohydride chains in both samples were released by treatment with alkaline borohydride. Nearly the same molar ratio of N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose, sulfate, and sialic acid was found in both preparations.

Animals↗
PubMed1998

Propofol enhances red cell antioxidant capacity in swine and humans.

PURPOSE: To determine the effect of an anaesthetic with antioxidant potential, propofol, on red blood cell (RBC) antioxidant enzyme activities and RBC susceptibility to peroxidative challenge. METHODS: Propofol was administered by intravenous bolus (2.5 mg.kg-1) and continuous infusion (36 and 72 ml.hr-1 in nine swine; 216 ml.hr-1 in two swine), to achieve serum concentrations between 5 and 30 micrograms.ml-1 for two hours at each rate. Arterial blood sampling was at 0, 10, 30, 60, and 120 min for each rate of infusion, for measurement of plasma propofol concentration, activities of plasma and RBC superoxide dismutase, glutathione peroxidase, glutathione reductase, RBC catalase, and RBC malondialdehyde (MDA) formation in response to ex vivo oxidative challenge with t-butyl hydrogen peroxide (tBHP; 1.5 mM). Antioxidant mechanisms were determined by in vitro study of MDA formation, GSH depletion, and oxidation of haemoglobin to methaemoglobin in human erythrocytes exposed to propofol 0-75 microM. The antioxidant potential of propofol was compared with that of alpha-tocopherol utilising the reaction with 2,4,6-tripyridyl-s-triazine (TPTZ). RESULTS: Propofol had no effect on plasma or RBC antioxidant enzyme activities. It inhibited RBC MDA production over the range of 0-20 micrograms.ml-1 (y = -18.683x + 85.431; R2 = 0.8174). Effective propofol concentrations for 25% and 50% reductions in MDA levels were 7-12 and 12-20 micrograms.ml-1, respectively. Propofol has a similar effect on human erythrocytes in vitro (R2 = 0.98). CONCLUSION: Propofol antagonises the effects of forced peroxidation of red cells at anaesthetic and sub-anaesthetic concentrations in swine. Its actions include scavenging of oxygen derived free radicals in a tocopherol-like manner.

Anesthetics, General↗
PubMed1999

Reduction of the nitrogen and carbon content in swine waste with algae and bacteria.

Animal waste causes environmental problems like eutrophication of ground and surface water or the pollution of the atmosphere because of its high NH4+ content. The aim of our study was to fix the nitrogen of swine waste as biomass. Therefore, an isolated alga, Chlorella sp., and bacteria naturally living in liquid manure were grown in batch cultures (containing diluted swine waste supplied with a nutrient solution) and continuous cultures (undiluted liquid manure) to achieve reduction of NH4+ and total organic carbon (TOC) contents. For continuous cultivation, a photobioreactor of our own design was used. The batch cultivation of Chlorella sp. and bacteria in swine waste resulted in good growth of both groups of organisms and in a reduction of 25% NH4+ and 80% TOC. In the continuous cultivation a steady state was not achieved owing to a change in the composition of the bacterial population. NH4+ was totally removed, but NO2- (up to 100 mM) was transiently released. NO3- was not detected. These effects might be explained by the presence of heterotrophic nitrifiers, which are able to oxidize NH4+ to NO2- and to reduce NO2- to gaseous compounds.

Animal Husbandry↗
PubMedDate not supplied

Experimental percutaneous extrahepatic portacaval shunt creation by transjugular approach in Swine.

The purpose of the study was to evaluate the feasibility of the creation of a percutaneous extrahepatic portacaval shunt (PEPS) in swine by a transjugular approach and to find a suitable stent-graft to use in PEPS. In 12 swine, the extrahepatic portal vein (PV) was entered from the inferior vena cava (IVC) by a needle system introduced from the transjugular approach. A catheter introduced through the transhepatic approach served as a target. Five types of stent-graft consisting of homemade Z stents and a polytetrafluoethylene cover were explored for PEPS creation. Eight animals had follow-up venograms up to 6 weeks or until the shunt became severely stenotic. Gross and histologic examinations were performed after the final follow-up venography. The PV punctures and stent-graft placement were difficult, but the PEPS was established in all animals. In four animals, the stent-graft failed to adequately cover the tract, causing severe hemorrhage. Only two shunts remained patent up to 6 weeks. The other shunts exhibited severe stenosis or occlusion. At gross examination, all shunts traversed the liver parenchyma of the caudate lobe surrounding the IVC. The extravascular PEPS portion was 4 mm to 2 cm long. All shunts entered the PV close to the splenomesenteric junction and exhibited neointimal formation. Shunt stenoses were caused by neointimal hyperplasia and occlusions by a superimposed thrombus. PEPS can be created by the transjugular approach in swine, but only the PV shunt entrance is extrahepatic. None of the tested rigid stent-grafts were suitable for PEPS creation. A short flexible stent-graft with flanged ends is suggested for further exploration.

Animals↗
PubMedDate not supplied

Experimental TIPS with spiral Z-stents in swine with and without induced portal hypertension.

PURPOSE: To assess the suitability of spiral Z-stents for transjugular intrahepatic portosystemic shunt (TIPS) and the influence of portal hypertension on shunt patency in young swine. METHODS: TIPS were established using spiral Z-stents in 14 domestic swine. In 7 animals, the portal venous pressure was normal; in the other 7, acute portal hypertension was induced by embolization of portal vein branches. Follow-up portal venography and histologic evaluations were done from 1 hr to 12 weeks after TIPS. RESULTS: Follow-up transhepatic portal venograms showed progressive narrowing of the shunt, most prominent in the midportion of the tract. Ingrowth of liver parenchyma between the stent wires found after 3 weeks led to progressive shunt narrowing and shunt occlusion by 12 weeks. A pseudointima grew rapidly inside the stent, peaked in thickness around 4 weeks, and decreased later. Acutely created portal hypertension rapidly returned to normal and there was no difference in TIPS patency between the two groups of animals. CONCLUSION: Although the spiral Z-stent can be used as a device for creation of TIPS in patients with cirrhotic livers, it is associated with extensive liver ingrowth in swine that leads to rapid shunt occlusion. Portal hypertension was only transient in this model.

Animals↗