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Comparison of six clinically used external defibrillators in swine.

BACKGROUND: External defibrillation has long been practiced with two types of monophasic waveforms, and now four biphasic waveforms are also widely available. Although waveforms and clinical dosing protocols differ among defibrillators, no studies have adequately compared performance of the monophasic or the biphasic waveforms. This is the first study to compare defibrillation efficacy among biphasic external defibrillators, and does so as part of a study comparing all commonly available waveforms using their respective manufacturer-provided and clinically used doses. METHODS AND RESULTS: Efficacy of six waveforms was tested in 852 short-duration ventricular fibrillation episodes in 14 swine. Protocol 1: 200-J monophasic damped sine (MDS) and monophasic truncated exponential (MTE) shocks were compared to 150-J biphasic shocks in six swine at the low-impedance of these animals. Protocol 2: Four commercially available biphasic defibrillators were compared using their respective manufacturer-recommended dose protocols in eight swine at low and simulated high-impedance. At low-impedance, all biphasic shocks achieved near-perfect success, while efficacy was significantly lower for MDS (67%) and MTE (30%) shocks. In protocol 2, first-shock success rates of the four biphasic defibrillators were uniformly high (97, 100, 100, and 94%) for low-impedance shocks, and decreased for high-impedance shocks (62, 92, 82, and 64%). There were statistically significant differences in efficacy among devices. CONCLUSIONS: Commonly used MDS and MTE waveforms provide markedly dissimilar efficacies. Despite impedance-compensation schemes in biphasic defibrillators, impedance has an impact on their efficacy. At high-impedance, modest efficacy differences exist among clinically available biphasic defibrillators, reflecting differences in both waveforms and manufacturer-provided doses.

Animals↗

Lower frequency (5 MHZ) intracardiac echocardiography in a large swine model: imaging views and research applications.

Our previous investigation indicated that, in the 50-114-kg weight range, the swine model provides transeosophageal echocardiographic normal values for cardiac structures comparable to those found in human adults. Intracardiac echocardiographic imaging using a 12.5-MHz ultrasound catheter is limited, due to ultrasonic attenuation. Transesophageal echocardiographic imaging of the right heart is also limited with its anterior anatomic location. To further study the utility of intracardiac imaging, we placed a 5-MHz (30 Fr) multiplane transducer at the junction of the superior vena cava and right atrium, in the right atrium and right ventricle in 8 closed-chest swine (weight 129 +/- 61 kg). In each animal, complete whole heart imaging was obtained, with tomographic views including the cardiac 4-chamber, right atrium, right ventricle and outflow, left atrium and ventricle, and basal great vessels. Major intracardiac anatomic landmarks (i.e., crista terminalis, right atrial appendage, coronary sinus orifice, interatrial septum, tricuspid valve, right ventricular outflow, pulmonary veins, mitral valve and left ventricular papillary muscles) were visualized in every swine. Thus, this 5-MHz multiplane transducer, as a prototype for a steerable low-frequency intracardiac ultrasound catheter, improved both whole heart and individual cardiac structure imaging from a single intracardiac location. Further technological development and refinement is needed for routine use in research and clinical imaging practice.

Animals↗

Decreased adventitial neovascularization after intracoronary irradiation in swine: a time course study.

BACKGROUND: Intracoronary radiation (IR) suppresses the formation of neointima after arterial injury in swine, through mechanisms incompletely understood. Neointimal development appears related to expansion of adventitial microvessels; we therefore examined the hypothesis that IR inhibits neointima formation through an anti-angiogenic effect. METHODS AND RESULTS: Juvenile swine were treated with either 0 or 15 Gy (192)Ir (gamma-source) and euthanized 3, 7, or 14 days later or treated with 18 Gy (90)Y (beta-source) and euthanized after 14 days. Adventitial area (AA), intimal area (IA), IA corrected for medial fracture length, and adventitial vessel area were assessed in both injured and uninjured segments by computer-aided histomorphometry on Verhoeff-Von Giesson stained sections. Adventitial vessel count (AVC) was enumerated visually on hematoxylin and eosin stained sections and confirmed by anti-factor VIII-associated antigen immunostaining for endothelial cells. AA and IA were reduced in injured arteries subjected to IR as compared to controls. The AVC was significantly lower in injured irradiated arterial segments as well as all uninjured segments as compared with injured control segments. In the injured and irradiated arteries, the AVC remained unchanged at 3, 7, and 14 days. The injured segments of arteries treated with IR demonstrated a significantly lower adventitial microvessel density (AVC/AA) as compared to the injured control segments. Comparison of gamma- and beta-irradiation at 14 days did not show any differences for vessel parameters and measurements of adventitial microvessels. IA and AVC were correlated positively (R(2) = 0.63, alpha = 0.79, p < 0.01). CONCLUSION: IR induced an early and sustained anti-angiogenic effect between 3 and 14 days. The relation between IA and AVC may indicate an antiproliferative effect associated with an anti-angiogenic effect independent of the type of radiation. CONDENSED ABSTRACT: Intracoronary radiation suppresses neointima formation after arterial injury in swine, through mechanisms and with consequences that are not fully known. Reduction of angiogenesis may inhibit restenosis. In the present study, intimal area and adventitial area were reduced in the intracoronary radiation groups 3-14 days after arterial injury as compared to their respective controls, with a parallel reduction in the adventitial vessel count and adventitial vessel density. Intimal area and adventitial vessel count were correlated positively. Neointima reduction after intracoronary radiation may depend not only on an antiproliferative effect but also on an anti-angiogenic effect.

Animals↗

Swine production.

The US swine industry is large and growing. The quantity of pork desired by consumers of US pork is growing at the rate of 1.5%/y. New production systems and new technology have enabled production per sow to grow at a rate of 4% annually in recent years. Consequently, the number of sows in the United States is declining. Because productivity growth is outpacing demand growth, the deflated price of hogs and pork is declining. Hog production and prices continue to exhibit strong seasonal and cyclic patterns. Pork production is usually lowest in the summer and highest in the fall. Production and prices tend to follow 4-year patterns. The US swine industry continues to evolve toward fewer and larger producers who rely on contracts for both hog production and marketing. In 2000, over half of the hogs marketed were from approximately 156 firms marketing more than 50,000 head annually. These producers finished 60% of their production in contract facilities. Over 90% of their marketings were under contract or were owned by a packer. These producers expressed a high level of satisfaction with hog production. Both they and their contract growers were satisfied with production contracts. These large producers were satisfied with their marketing contracts and planned to continue them in the future. The hog industry has changed a great deal in the last decade. There is little reason to believe this rapid rate of change will not continue. This swine industry is highly competitive and profit driven. Profit margins are too small to allow producers the luxury of ignoring new technology and innovative production systems. Consequently, hog production will continue its rapid evolution from traditional agriculture to typical industry.

Animal Husbandry↗

Techniques of inhalation anesthesia in ruminants and swine.

This article reviews the implementation of inhalation anesthesia in large and small ruminants and swine. A brief discussion of the general considerations for inhalation anesthesia of large animals is followed by a review of the pharmacology of inhalation agents, induction procedures commonly used when anesthetizing ruminants and swine, methods of assessing depth of anesthesia and maintenance of anesthesia, and anesthetic machines and delivery systems appropriate for use in large and small ruminants and swine.

Anesthesia, Inhalation↗

Elevated potassium intake inhibits neointimal proliferation in the swine coronary artery.

BACKGROUND: Previously, we reported that elevated extracellular potassium concentration in vitro inhibited proliferation and migration of vascular smooth muscle cells, formation of free radical compounds by macrophages, and reduced platelet sensitivity to agonists. More recently, we described a reduction in neointimal proliferation after balloon angioplasty injury in the carotid arteries of rats associated with an elevation of dietary potassium intake during a 4-week experiment. In the present study we conducted a similar investigation in the swine coronary artery balloon angioplasty model. PROCEDURES: Two groups of seven castrated male swine were studied; for 28 days the normal potassium group consumed a diet containing 0.25% potassium and the high potassium group ate diet containing 2.0% potassium. After 14 days on the diet, balloon angioplasty was performed. After an additional 14 days on the same diets the hearts were removed, and normal and lesioned sections of the artery were analyzed histologically. RESULTS: The neointimal area was markedly less in the high potassium group than in the normal potassium group, 0.33+/-0.04 mm2 v 0.74+/-0.10 mm2 (P < .004). Neointimal area-to-total wall area ratio in the normal potassium group averaged 0.199+/-0.018, significantly greater than the ratio computed for the elevated potassium group, 0.120+/-0.015 (P < .006). CONCLUSION: These results support the hypothesis that a high level of dietary potassium intake inhibits neointimal proliferation after balloon angioplasty in the swine coronary artery.

Aldosterone↗

Inhalation of swine-house dust increases the concentrations of interleukin-1 beta (IL-1 beta) and interleukin-1 receptor antagonist (IL-1ra) in peripheral blood.

Inhalation of dust in swine confinement buildings causes airway inflammation and systemic symptoms. The proinflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) increase in bronchoalveolar and nasal lavage fluid, and in serum. The aim of this investigation was to study changes in the IL-1 family of cytokines in peripheral blood in 36 healthy volunteers exposed to swine house dust for 3 h. Interleukin (IL-1 beta) was measured in platelet poor plasma and in a mononuclear cell fraction (PBMC) and interleukin-1 receptor antagonist (IL-Ira), IL-6 and TNF-alpha were measured in serum 4 and 7 h after the start of 3 h exposure. Lung function and a methacholine bronchial provocation test were performed before and 7 h after the start of exposure. The leukocyte count in whole blood and the mononuclear cell count in PBMC were examined before, and 4 and 7 h after the start of exposure. The concentration of airborne inhalable dust and endotoxin were measured using personal samples. The concentration of inhalable dust was 23 (20-30) mg m-3 (median 25th-75th percentile) endotoxin was 1.1 (0.8-1.4) micrograms m-3 and respirable dust (n = 8) was 1.0 (0.7-1.2) mg m-3. IL-1 beta increased from < 0.125 to 0.9 (0.5-1.3) ng l-1 in plasma and from 1.6 to 2.7 (1.1-4.4) ng l-1 in PBMC (P < 0.01). IL-1 ra, IL-6 and TNF-alpha increased 2-, 12- and 2-fold in serum after exposure, respectively. Changes in IL-1 ra correlated with changes in FEV1, bronchial responsiveness, oral temperature (P < 0.01) and blood white cell count (P < 0.05). IL-1 beta correlated significantly with temperature (P < 0.05). These results indicate that IL-1 beta and IL-1 ra increase in peripheral blood following inhalation of swine house dust and may participate in and modulate the inflammatory response together with IL-6 and TNF-alpha.

Adolescent↗

Aspergillus niger absorbs copper and zinc from swine wastewater.

Wastewater from swine confined-housing operations contains elevated levels of copper and zinc due to their abundance in feed. These metals may accumulate to phytotoxic levels in some agricultural soils of North Carolina due to land application of treated swine effluent. We evaluated fungi for their ability to remove these metals from wastewater and found Aspergillus niger best suited for this purpose. A. niger was able to grow on plates amended with copper at a level five times that inhibitory to the growth of Saccharomyes cerevisiae. We also found evidence for internal absorption as the mechanism used by A. niger to detoxify its environment of copper, a property of the fungus that has not been previously exploited for metal bioremediation. In this report, we show that A. niger is capable of removing 91% of the copper and 70% of the zinc from treated swine effluent.

Animals↗

Nutrient recovery from swine lagoon water by Spirodela punctata.

Spirodela punctata 7776, the best duckweed strain in total protein production selected from in vitro screening experiments with synthetic swine lagoon water medium was examined for N and P recovery. It has shown a capability to grow in and to remove N and P from synthetic swine lagoon water with high N (240 mg NH4 N/l) and P (31.0 mg PO4 P/l) levels. A lag period of approximately 96 h was observed before the duckweed started to grow. During the lag period, utilization of N and P by the duckweed was very slow. The rates of N and P uptake, and duckweed growth increased with the increase of the initial N and P concentrations in the medium. The highest rates of N and P uptakes, and duckweed growth observed in this study were 0.955. 0.129 mg/l-h, and 1.33 g/m2-h (or 31.92 g/m2-day), respectively. The N:P ratio in swine lagoon water is adequate for growing the duckweed.

Animals↗

Percutaneous deployment of a valved bovine jugular vein in the swine venous system: a potential treatment for venous insufficiency.

PURPOSE: To develop a system for potential use in the treatment of chronic venous insufficiency by using percutaneous techniques. MATERIALS AND METHODS: A segment of a glutaraldehyde-fixed bovine external jugular vein with valves was trimmed and sutured to a nitinol stent. Animals were premedicated and anesthetized (n = 11). Venography of the right external jugular vein, inferior vena cava (IVC), and common iliac vein was performed. Deployment was accomplished via a sheath (12-24 F) with use of fluoroscopic guidance. Eleven bioprostheses were deployed in 11 animals. Bioprostheses were deployed in the IVC (n = 3) or right external iliac vein (n = 6). Animals were killed immediately after deployment (n = 7) at 1 week (n = 1) or at 2 weeks (n = 2). One animal was found dead in the cage. At necropsy, each bioprosthesis (n = 4) was explanted and histopathologic analysis was performed. RESULTS: Deployments of the bioprostheses were successful in nine of 11 swine. Two deployments were unsuccessful (one accidental deployment in the right renal vein, one deployment in the IVC caused rupture of the vein). Postdeployment venography (n = 9) confirmed no reflux (in the recumbent position of the swine) of the valve leaflets and patency of the vein inferior to the level of the bioprostheses. in the first group of animals (n = 5), valve leaflets were normal and competent. In the survival animal group (n = 4), the bioprostheses remained patent without evidence of thrombus formation by ascending and descending venography. Gross inspection of the explanted bioprostheses (n = 4) demonstrated grossly normal valves that fully occluded the lumen. Complications included hemarthrosis (n = 1), death (n = 1), and bioprosthesis thrombosis immediately after deployment (n = 1). Histopathologic analysis showed endothelial cells covering the luminal surfaces. The wall of the bioprostheses had granulomatous response and foreign body reaction. Bacterial contamination was noted in one bioprosthesis. CONCLUSIONS: Deployment of a glutaraldehyde-fixed bovine vein sutured to a self-expanding nitinol stent in the swine iliac vein or IVC is technically feasible. Development of a venous bioprosthesis that can be placed percutaneously may have important clinical applications as an endovascular treatment for chronic venous insufficiency when it is due to valvular incompetence.

Alloys↗

Intravascular US-guided direct intrahepatic portacaval shunt with a PTFE-covered stent-graft: feasibility study in swine and initial clinical results.

PURPOSE: To determine the feasibility of the creation of a direct intrahepatic inferior vena cava (IVC)-to-portal-vein shunt with puncture guided by a transfemorally placed intravascular ultrasound (IVUS) probe and use of a polytetrafluoroethylene (PTFE)-covered stent-graft. MATERIALS AND METHODS: In five swine, transjugular access was used to perform a direct puncture from the IVC to the portal vein with use of a modified Rosch-Uchida Portal Access set directed with real-time IVUS (9 MHz) introduced from a transfemoral venous approach. The direct intrahepatic portocaval shunt (DIPS) was then created with single or overlapping PTFE-covered Palmaz stents placed through a 10-F sheath and dilated to a diameter of 8 mm. Follow-up was performed with transhepatic portography at 2, 4, and 8 weeks. Animals were killed when shunts occluded or at the termination of the study at 8 weeks. Gross and microscopic histologic study was performed on sacrificed animals. A similar technique was used to create DIPS in five patients with intractable ascites, with follow-up by US and venography. RESULTS: All experimental DIPS created in swine were created without complications. Portal vein punctures were achieved in four of five swine on the first or second pass of the needle. Follow-up transhepatic portography at 2 weeks demonstrated occlusion of two shunts, both explained by technical reasons at sacrifice. At 4 and 8 weeks, the remaining three shunts were patent on portography. Histology showed a thin neointimal lining with no significant tissue ingrowth or hyperplasia. Clinically, in five patients, successful puncture of the portal vein from the IVC was achieved in one to three passes. Creation of DIPS led to a reduction of mean portosystemic gradient from 18-29 mm Hg (mean, 24 mm Hg) to 9-10 mm Hg (mean, 9 mm Hg). One patient died of liver failure 2 days after creation of DIPS. The other four patients were doing well 2-15 months (mean, 8 months) after the procedure, with patency confirmed by US and venography. CONCLUSION: Creation of DIPS is technically feasible, and the direct IVC-to-portal-vein puncture can be done accurately with real-time IVUS guidance. Further studies and longer follow-up are necessary to determine if the short length of the PTFE-covered stent-graft and avoidance of the hepatic vein will increase the long-term patency compared to standard transjugular intrahepatic portosystemic shunt creation.

Animals↗

Creation of compression gastroenterostomy by means of the oral, percutaneous, or surgical introduction of magnets: feasibility study in swine.

PURPOSE: The use of magnets placed surgically, percutaneously, and orally to create compression gastroenteric anastomoses was evaluated in 11 swine. MATERIALS AND METHODS: Disc-shaped, jacketed rare-earth magnets with cutting edges varying in diameter from 0.250 inch (6.4 mm) to 0.500 inch (12.7 mm) were used in seven swine, and rectangular types were used in three swine. Magnets were implanted surgically in five and introduced by means of standard interventional techniques through a gastrostomy in two and perorally in four animals. Anastomoses (n = 8) were studied grossly and histologically for acute changes at 5-13 days and for 30-day patency in one. RESULTS: Of the nine surviving pigs, there were seven completely patent anastomoses and one partially patent anastomosis at 7-13 days. At 5 days the anastomosis was not patent in the remaining animal. One anastomosis became occluded at 30 days. There was no anastomotic leakage, infection, or bleeding. CONCLUSIONS: Leak-free gastrojejunostomies can be created by inserting magnets perorally, percutaneously, or surgically.

Anastomosis, Surgical↗

Phosphodiesterase-III-inhibition with amrinone leads to contracture development in skeletal muscle preparations of malignant hyperthermia susceptible swine.

BACKGROUND AND OBJECTIVE: The phosphodiesterase-III (PDE-III) inhibitor enoximone-induced marked contractures in skeletal muscle specimens of malignant hyperthermia (MH) susceptible (MHS) human beings and swine. Whether this is a substance specific effect of enoximone or caused by inhibition of PDE-III remained unclear. Therefore, the effects of the PDE-III inhibitor amrinone in porcine MH normal (MHN) and MHS skeletal muscles were investigated. METHODS: MH-trigger-free general anaesthesia was performed in eight MHS and eight MHN swine. The MH status of the swine was determined by detection of the Arg615-Cys point mutation on chromosome 6 indicating MH susceptibility. Skeletal muscle specimens were excised for the in vitro contracture tests with amrinone. Amrinone was added cumulatively every 5 min to muscle specimens in order to obtain organ bath concentrations between 20 and 400 micromol L(-1). The in vitro effects of amrinone on muscle contractures and twitches were measured. RESULTS: Amrinone-induced contractures in all skeletal muscle preparations. MHS muscles developed contractures at significantly lower bath concentrations of amrinone than MHN muscles. Contractures of MHS compared to MHN muscles were significantly larger at bath concentrations of 80, 100, 150, 200 and 400 micromol L(-1) amrinone. Muscle twitches remained unchanged up to and including 200 micromol L(-1) amrinone. CONCLUSIONS: Inhibition of PDE-III in general elicited higher contractures in MHS than in MHN muscles. Therefore, a contribution of PDE-III and the cyclic adenosine monophosphate (cAMP) system in the pathophysiology of MH must be suspected.

3',5'-Cyclic-AMP Phosphodiesterases↗

Purification and characterization of UDP-GalNAc:polypeptide N-acetylgalactosaminyl transferase from swine trachea epithelium.

UDP-GalNac: polypeptide N-acetylgalactosaminyltransferase from swine trachea epithelium was purified to homogeneity by procedures which included affinity chromatography on Sepharose 4B columns containing bound deglycosylated Cowper's gland mucin. The enzyme, purified 12,000-fold from microsomes with a yield of 40%, showed only a single band on dodecyl sulfate polyacrylamide gel electrophoresis. The homogenous enzyme has an apparent molecular mass of 70,000 Da, as determined by gel electrophoresis or gel filtration. The transferase has a broad pH optimum between 6.7-7.8 with maximal activity at pH 7.2, and required Mn2+ for activity with maximal activity at 5-7.5 mM. Higher concentrations of Mn2+, inhibited the enzyme. The purified transferase was specific for UDPGalNAc and glycosylated both threonine and serine residues in tryptic peptides prepared from deglycosylated Cowper's gland and swine and human trachea mucins. The apparent Km of the transferase for UDPGalNAc was 6.3 microM, and the Km values for deglycosylated Cowper's gland and human and swine trachea mucins were 0.83, 1.12 and 0.94 mg/ml, respectively. The Vmax of the purified enzyme was 2.1 micromol/min/mg with deglycosylated Cowper's gland mucin, as the glycosyl acceptor. However, the activities with peptides prepared from deglycosylated mucins by limited acid hydrolysis were 20-fold greater than the intact glycoprotein under identical conditions. The deglycosylated mucins and larger peptides aggregated with time of storage and precipitated from solution. Aggregation was accompanied by a corresponding loss of enzymatic activity even after dispersion of the aggregate by sonication. The deglycosylated mucins which were prepared by chemical treatment and periodate oxidation still contained about 20% of the N-acetylgalactosamine present in the intact mucin. When this residual amino sugar was removed by periodate oxidation the completely deglycosylated mucins became very poor substrates for the purified transferase. Data obtained in the current study indicate that the accessibility of serine and threonine in the polypeptide chains of mucin glycoproteins significantly influences the rate of glycosylation of these amino acids. The best substrates and affinity ligand for the enzyme were fragments of incompletely deglycosylated mucin polypeptide chains.

Amino Acid Sequence↗

Molecular cloning and nucleotide sequence of 3'-terminal region of classical swine fever virus LPC vaccine strain.

A cDNA of the 3'-terminus of classical swine fever virus (LPC vaccine strain) was cloned and sequenced. The 3431 nucleotides and deduced amino acid sequences were compared with those of other pestiviruses, and the similarity of nucleotide sequences and deduced amino acid sequences were found to be 84-95% and 95-98%, respectively. Similar to other isolates of classical swine fever virus, the sequenced region included the non-structural gene p58 (NS5A) and part of p76 (NS5B) gene. The p76 gene of LPC vaccine strain also contained a highly conserved motif G-D-D (Gly-Asp-Asp) that is present in the RNA replicase of positive-stranded RNA viruses. With the sequence data currently available, we carried out a phylogenetic analysis and obtained a genealogical relationship among members of the classical swine fever virus.

Amino Acid Sequence↗

Persistence of MHC DR nonexpression on swine cells by introduction of a mutated MHC class II transactivator gene: a comparison with the effect induced by antisense RNA.

CIITA (class II transactivator) is a coactivator essential for transcription of MHC class II genes. In this study, a construct with a mutated CIITA gene with N-terminal domains depleted was constructed. This mutated CIITA (mCIITA) was able to repress DR and DQ expression in 45.0-60.0% of the mCIITA-transfected clones of swine endothelial cell line PIEC and in B cell line L23, as well as in human cell lines HeLa and Raji. Similarly, 30.0-46.7% of swine cell clones containing the human CIITA antisense RNA also failed to express DR molecules. However, the persistence of the DR repression on the cell lines is quite different. Transfection with mCIITA was persistent for at least 120 days, while with the CIITA antisense RNA, persistence existed for only 35-45 days. To explore the underlying mechanism, Raji cells were transfected with pUHD10-3-mCIITA, a mCIITA-containing, doxycycline-dependent plasmid. The intensity of DR repression is correlated quite well with the efficiencies of the mCIITA expression within the cells in a doxycycline dose-dependent manner. This implicates a competition between the mCIITA and its endogenous full-length counterpart. In addition, we were able to show that purified human CD4 T cells did not respond to the mCIITA-transfected PIECs in xenogeneic mixed lymphocyte endothelial reaction (MLER). The stimulating indices (SI) were only 1.0-1.5, compared with 15.2-18.2 for those transfected with empty vector or an initiation codon-depleted mCIITA that is dysfunctional for protein translation. The results we obtained, especially those for persistent suppression of class II genes, show promise for the possible development of mCIITA-transgenic swine for organ/tissue xenotransplantation.

Animals↗

Working in swine-confinement buildings causes an accelerated decline in FEV1: a 7-yr follow-up of Danish farmers.

Work in swine confinement units causes exposure to high levels of organic dust and is associated with a high prevalence of work-related respiratory symptoms and probably with accelerated decline in forced expiratory volume in one second (FEV1). A 7-yr follow-up on FEV1, forced vital capacity (FVC), bronchial reactivity, and respiratory symptoms was performed on 181 Danish farmers. The participation rate was 76.3% and nonparticipants had more symptoms, were more likely to be current-smokers and had lower lung function in the first survey than participants in both surveys. Farmers who worked exclusively with pigs in the follow-up had an accelerated decline in FEV1 but not in FVC compared with dairy farmers, where the observed decline in FEV1 was close to the expected. For a nonsmoking pig farmer compared to a nonsmoking dairy farmer the mean additional decline in FEV1 was 17 mL x yr(-1) (53.0 mL x yr(-1) versus 36.1 mL x yr(-1)). The authors conclude that working in swine confinement units causes an accelerated decline in forced expiratory volume in one second but not in forced vital capacity. The mean decline is approximately 0.5 L during a working life and some farmers will develop clinically significant airway obstruction due to work in swine confinement units.

Adult↗

Human complement regulatory proteins protect swine-to-primate cardiac xenografts from humoral injury.

The susceptibility of xenografts to hyperacute rejection is postulated to reflect in part failure of complement regulatory proteins (CRPs) to control activation of heterologous complement on graft endothelium. To test this concept, transgenic swine expressing the human CRP decay accelerating factor and CD59 were developed using a novel expression system involving transfer of the proteins from erythrocytes to endothelial cells. Hearts from transgenic swine transplanted into baboons had markedly less vascular injury and functioned for prolonged periods compared to hearts from nontransgenic swine. These results indicate that expression of human CRPs in xenogeneic organs may contribute to successful xenografting and suggest that intercellular protein transfer might be a useful approach for expression of heterologous proteins in endothelial cells.

Animals↗