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PubMed1984

Ethanol consumption and serum lipid profiles in Sinclair(S-1) miniature swine.

Ethanol consumption was correlated with changes in acyl group profiles of phosphatidylcholine and triacylglycerols in serum of Sinclair(S-1) miniature boars. Serum triacylglycerols in the control pigs were high in linoleate (18:2) (48%) and low in stearate (18:0 (3%). Upon feeding with 10% (w/v) ethanol ad lib for two weeks, the proportion of 18:2 in serum triacylglycerols decreased to 12-15% with a concomitant increase in 16:0, 18:0 and 18:1. Similar, but less extensive, acyl group changes were observed in the serum phosphatidylcholine. In addition, there was a decrease in the proportion of 20:3(n-6), but a biphasic change was shown in 20:4(n-6) with respect to ethanol consumption. In general, the high ethanol consumers (7.0 g/kg/day) indicated a more rapid rate of acyl group change than the low consumers (3.8 g/kg/day). Upon withdrawal of ethanol, acyl groups of triacylglycerols rapidly returned towards the control values, whereas only small changes were observed for the recovery in phospholipids. In this situation, the low-consumer group indicated a more rapid recovery than the high-consumer group. Results indicate that with the swine model, serum lipid changes can be a useful parameter for correlating biological changes upon ethanol consumption.

Alcohol Drinking↗
PubMed1986

The effects of different total parenteral nutrition fuel mixes on skeletal muscle composition of infant miniature pigs.

Two groups of 10-day-old miniature pigs were maintained on isocaloric and isonitrogenous total parenteral nutrition (TPN) regimens for nine days. One group received nonprotein energy as glucose, whereas the second group received a mixture of fat and glucose. The administration of the amino acid/glucose fuel mix resulted in higher plasma insulin but lower glucagon concentrations compared to the amino acid/glucose/fat mix. Differences also were observed in the composition of skeletal muscle, which contained higher concentrations of alkali-soluble (AS) proteins (chiefly cellular protein) and DNA, when glucose was the only source of nonprotein energy. Intracellular sodium and water content and nonalkali-soluble proteins (largely extracellular proteins) were lower in the skeletal muscle of the amino acid/glucose group than in that of the group receiving the fat regimen. No differences in RNA concentration, RNA/AS protein, or AS protein/DNA ratios were observed. These data suggest that conditions of high insulin production in the postnatal growth period favored increased DNA replication and accretion of AS protein. The differences in water and electrolyte composition indicate that the rate of chemical maturation of skeletal muscle was slower in the piglets receiving amino acids/glucose/fat than in those on the glucose regimen. This study has demonstrated that the source of nonprotein energy can influence skeletal muscle maturation in the postnatal period.

Animals↗
PubMed1992

Vascular changes in the dental pulp in the hypercholesterolemic miniature swine.

The aim of this study was to evaluate the effect of hypercholesterolemia and a cholesterol-lowering diet on the blood vessels of dental pulp. Eighteen miniature swine were assigned to three different groups on the basis of their diets: hog finisher; hog finisher with added fat and cholesterol, or hog finisher with added fat and cholesterol supplemented with grapefruit pectin. The cholesterol levels were monitored monthly for the duration of the experiment. Biopsy specimens of the aorta, coronary arteries, kidneys, and mandibular incisor teeth were prepared for histologic examination. The degree of narrowing of the central pulpal arterioles was measured with a Bioquant II digitizer attached to an Apple IIe computer and a Nikon Labophot light microscope. A few (9.8%) of the pulpal arterioles of the swine on a high-cholesterol diet had atheromatous plaques, but no complete vascular obstructions were observed. No degenerative changes were observed in any of the dental pulps examined.

Animals↗
PubMed1995

Interferon induction in swine lymphocyte antigen-defined miniature pigs.

Interferon was induced in two groups of swine lymphocyte antigen (SLA)-defined miniature pigs with polyinosinic: polycytidylic acid complexed with poly-L-lysine and carboxymethylcellulose. The group 1 pigs were low antibody-response phenotypes (SLAa/a, SLAa/c, SLAc/c), and the group 2 pigs were high antibody-response phenotypes (SLAd/d, SLAd/g, SLAg/g). Six hours after induction the antiviral tires were not influenced by the SLA group, but higher titres were observed in females. Higher antiviral titres were found in group 2 pigs before treatment and 24 hours after treatment, and higher titres were found in female pigs. The antiviral titres before and after treatment were also influenced by the sire. Group 2 pigs had a lower total leucocyte counts before treatment, and there was a significant reduction in leucocyte numbers in both groups six hours after induction, due mainly to a large reduction in lymphocyte counts.

Animals↗
PubMed1991

Unilateral hypoxic pulmonary vasoconstriction in the dog, pony and miniature swine.

The hypoxic pulmonary vasoconstrictor response to unilateral hypoxia was analyzed in pentobarbital anesthetized dogs (n = 5), miniature swine (n = 5), and ponies (n = 5). The left and right lungs (LL, RL) were separately ventilated with the LL exposed to inspired oxygen concentrations (CIO2) of 100%, 12%, 8% or 4%, while the RL always received a CIO2 = 100%. Pulmonary blood flow distribution was measured using 15 microns radioactive microspheres. LL PAO2, and percent pulmonary blood flow diversion (%FD) were calculated at each CIO2. At CIO2 of 4% there were significant differences (P greater than or equal to 0.05) between the %FD responses of each species (mean +/- S.E.): the %FDswine (95.1 +/- 1.3) greater than %FDpony (76.0 +/- 4.6) greater than %FDdog (50.1 +/- 9.4). For all species, the %FD was inversely related to the level of regional hypoxia, but there were marked species differences in the magnitude and sensitivity of hypoxic pulmonary vasoconstriction with the swine being the strongest responder, the pony intermediate, and the dog the weakest responder.

Animals↗
PubMed1991

A miniaturized fibrinolytic assay for plasminogen activators.

This report describes a micro-clot lysis assay (MCLA) for evaluating fibrinolytic activity of plasminogen activators (PA). Fibrin clots were formed in wells of microtiter plates. Lysis of the clots by PA, indicated by change in turbidity (optical density, OD), was monitored with a microplate reader at five minutes intervals. Log-log plots of PA dilution versus endpoint, the time at which the OD value was halfway between the maximum and minimum value for each well, were linear over a broad range of PA concentrations (2-200 International units/ml). The MCLA is a modification and miniaturization of well established fibrinolytic methods. The significant practical advantages of the MCLA are that it is a simple, relatively sensitive, non-radioactive, quantitative, kinetic, fibrinolytic micro-technique which can be automated.

Chromogenic Compounds↗
PubMed1987

Influence of the swine major histocompatibility complex on reproductive traits in miniature swine.

Three swine leukocyte antigen (SLA)-defined strains of miniature swine and one recombinant strain were examined to evaluate the influence of the SLA Complex on litter size and piglet survivability. To separate the effects of sire and dam SLA haplotype from other sire and dam effects, a general linear model was employed to analyse data from 58 litters. Analysis of variance showed that sire and dam haplotype each contributed significantly to the variability observed in litter size among the sire and dam SLA combinations examined (P less than 0.0001, P less than 0.05, respectively). Sow SLA-haplotype as well as sire and dam effects other than those related to haplotype were significant factors contributing to survival until weaning (8 weeks) (P less than 0.10, P less than 0.07, P less than 0.001, respectively), but sire SLA-haplotype did not contribute significantly to this trait. Expected and observed haplotype frequencies of offspring in each litter were compared using chi-square analysis. A discrepancy was observed only in offspring from SLAa/d by SLAa/d matings, for which significantly fewer SLAa/a piglets were weaned than expected (P less than 0.06). Laparotomy during day 35-50 of pregnancy suggested that litter size was not an accurate estimate of ovulation rate and that ovulation rate was similar for dams of ad, ac and dd haplotypes.

Animals↗
PubMed1987

Structure and expression of class I MHC genes in the miniature swine.

The genome of the miniature swine, unlike other species, contains a relatively small class I MHC gene family, consisting of only seven members. This provides an excellent system in which to identify and characterize the regulatory mechanisms which operate to both coordinately and differentially regulate the expression of a multi-gene family. The structure of class I SLA genes, like other class I genes, consists of eight exons encoding a leader sequence, three extracytoplasmic domains, a transmembrane domain and intracytoplasmic domains. Despite the common structure, two sub-families of class I genes can be distinguished within the SLA family. One, containing the closely related PD1 and PD14 genes, encodes the classical transplantation antigens. Another contains the highly divergent PD6; the functions of the products of this subfamily, if any, are not known. The class I SLA genes share some common regulatory mechanisms, as evidenced by the fact that all three genes analyzed are transcribed in mouse L cells. Furthermore, interferon treatment of transfected mouse L cells enhances expression of all three genes. Both PD1 and PD6 are transcribed in vivo, where the highest levels of expression are observed in lymphoid tissues. Superimposed on the common patterns of class I gene expression are distinct ones, as evidenced by the findings that PD1 is preferentially expressed in B cells, whereas PD6 is preferentially expressed in T cells. These differences may reflect the extensive divergence of the 5' flanking sequences of these genes. Future studies will be aimed at elucidating the precise molecular interactions and mechanisms which give rise to the observed differential expression.

Animals↗
PubMed1989

Immunological responses of cross-bred and in-bred miniature pigs to swine poxvirus.

Swine poxvirus (SPV), topically and subdermally applied to skin of the inguinal region of cross-bred and in-bred miniature pigs, caused typical pox lesions to occur with a pustular stage at 4 to 5 days p.i., and healing by 10 to 14 days p.i. Following inoculation, peripheral blood lymphocytes (PBLs) of the pigs showed lower transformation responses to SPV and mitogens (Concanavalin A, phytohemagglutinin and 12-0-tetradecanoyl-phorbol 13-acetate) than PBLs from uninoculated controls. The PBLs generally responded to SPV from 7 to 9 days p.i. to 23 to 30 days p.i. with a maximum transformation response at the 12 to 13 days p.i. interval. Sera from the animals generally showed presence of SPV-neutralizing antibody as early as 7 days p.i. and a peak titer at 20 days p.i. of 1:512. No detectable SPV-antibody was observed at 50 days p.i. By 51Cr release assays, PBLs displayed the ability to lyse target cells in the presence of SPV-antibody with peak lysis from the 11th through the 21st day p.i. An antibody-histocompatibility restricted cell lysis was observed at 11 and 14 days p.i. When PBLs were depleted of adherent cells, there was a reduction in lysis of target cells indicating the adherent cells were instrumental as effector cells in the presence of SPV-antibody. Control pigs not exposed to SPV showed no PBL response to SPV-antigen. Partially histocompatible and non-histocompatible porcine kidney cells were found useful as cell models for evaluating SPV-infected pigs in their effort to immunologically respond to SPV.

Animals↗
PubMed1991

Ventricular septal defects in a family of Yucatan miniature pigs.

We have studied the hearts from a colony of Yucatan miniature pigs with spontaneously occurring congenital defects. Ventricular septal defect was encountered in 57 of 81 neonates from 15 consecutive litters. Of 73 hearts preserved for morphological assessment, 52 were found to have defects within the ventricular septum remarkably similar to those observed in humans with deficient ventricular septum. The defects, including 3 which had closed spontaneously, were perimembranous in 34, muscular in 12 and doubly committed and juxtaarterial in 6 hearts. Atrial septal defects were found in 12 of the 52 hearts with deficient ventricular septation; only 1 atrial septal defect was seen among 21 hearts with an intact ventricular septum. Anomalies of the aortic arch were associated with ventricular septal defect in 2 cases; 1 with a solitary arterial trunk and one with hypoplasia of the aorta and patent arterial duct. All these findings are replicated in human hearts. This strain of pig provides an ideal large animal model for morphologic and genetic investigations concerning the details of ventricular septation, including potential mechanisms of late spontaneous closure.

Animals↗
PubMed1995

Effect of CCK-8 on myoelectrical activity of the gastrointestinal tract in the conscious miniature pig.

In conscious miniature pigs, with implanted electrodes in the wall of the antrum pylori, duodenum, jejunum, and ileum, the influence of IV infusions of CCK-8 (17.5 and 175 pM/kg/min) on gastrointestinal myoelectrical activity was measured. Although both doses under study induced a decrease in antral spike activity. only the higher dose resulted in an overall decrease in integrated myoelectrical activity. In the ileum both doses augmented spiking activity during the infusion, but inhibited electrical activity after the end of the infusion. No response was observed in the duodenum and jejunum. The experiments demonstrate the overall inhibitory effect of CCK-8 on antral electrical activity and its stimulatory influence on ileal smooth muscle.

Animals↗
PubMed1996

Effect of the C-terminal tetrapeptide amide of gastrin (CCK-4) and pancreatic polypeptide on gastrointestinal electrical activity in the conscious miniature pig.

The effect of IV infusion of CCK-4, 33.2 and 332 pM/kg/min, and pancreatic polypeptide (PP), 4.8 and 48 pM/kg/min, on gastrointestinal electrical activity was studied in conscious miniature pigs with electrodes implanted in the wall of the antrum pylori and small intestine. In the antrum pylori infusion of the higher dose of both peptides provoked an increase in frequency of the basic electrical rhythm together with a decrease in frequency of spike bursts. In the studied dose range CCK-4 and PP were without influence on small intestinal electrical activity.

Amides↗
PubMed1990

Transplantation in miniature swine: analysis of graft-infiltrating lymphocytes provides evidence for local suppression.

Previous studies from this laboratory have demonstrated that swine tolerant of class I disparate renal allografts show peripheral antidonor cellular reactivity which can be augmented by skin grafting. To assess the possibility of local suppression, cell-mediated lymphocytotoxicity of graft-infiltrating lymphocytes was compared to that of peripheral blood lymphocytes from three tolerant and four acutely rejecting recipients of class I--disparate renal allografts. Mixed lymphocyte cultures using peripheral blood lymphocytes or graft-infiltrating lymphocytes and an equal number of irradiated peripheral blood lymphocyte stimulators were incubated for 6 days and tested in a 6-hr 51Cr release assay. Graft-infiltrating lymphocytes from rejecting animals had potent antidonor cell-mediated lymphocytotoxic activity with or without in vitro stimulation. Anti-third-party reactivity was seen with appropriate stimulation, suggesting heterogeneity of graft-infiltrating lymphocyte cultures. Peripheral blood lymphocytes from rejectors generated donor-specific cell-mediated lymphocytotoxicity. Graft-infiltrating lymphocytes from tolerant animals generated no antidonor cell-mediated lymphocytotoxicity with or without in vitro stimulation, but generated an anti-third-party response. Peripheral blood lymphocytes from tolerant animals displayed both antidonor and anti-third-party reactivity with appropriate in vitro stimulation. These data support the hypothesis that local suppression may contribute significantly to maintenance of tolerance to class I disparate renal allografts in miniature swine.

Animals↗
PubMed1996

Effect of major histocompatibility complex matching on the development of tolerance to primarily vascularized renal allografts: a study in miniature swine.

Prevention of rejection and the induction of transplantation tolerance are two related but separable phenomena that must both be considered in the analysis of the response to a transplanted organ. It is frequently hard to separate these phenomena in assessing the outcome of clinical transplants, because patients are rarely studied in the absence of immunosuppressive agents. Use of our partially inbred miniature swine has permitted us to examine the effects of selective MHC matching on transplant survival, and the data indicate that matching has an effect on both phenomena. Prevention of early rejection with CyA was possible for all mismatches examined, although it was clearly more difficult with increasing degrees of mismatching. On the other hand, tolerance induction after cessation of the immunosuppressive agent was dependent on presence of at least one matched MHC locus between the donor and recipient, with complete class II matching appearing to be the most successful way of assuring long-term graft survival. It is also apparent from our data that although durable tolerance to primarily vascularized renal allografts could be induced across a variety of selective MHC disparities, all cases involving a class II mismatch (ie, selective class I matched or one-haplotype full MHC mismatched kidney allografts) underwent spontaneously reversible rejection crises during the early follow-up period. Such a clinical course might be unacceptable for human clinical trials, even though the transient renal dysfunction may reflect events involved in tolerance induction rather than true rejection (Gianello et al: Immunol Rev 133:19, 1993.). Indeed, we do not yet know whether or not further immunosuppressive treatment at the times of such crises may prevent rather than facilitate the induction of tolerance. On the other hand, in the case of selective two-haplotype class I mismatch the regimen utilized was capable of inducing tolerance to renal allografts in 100% of the recipients with minimal or no renal dysfunction throughout the follow-up period. Although the excellent results achieved with current antirejection agents has led to debate about the wisdom of HLA matching for cadaver transplants in terms of preventing rejection, our data would suggest that such matching might be of even greater importance for success of protocols in which attempts are made to induce transplantation tolerance. Because class II antigens are less polymorphic than are class I antigens, mismatching for class I antigens may be achievable for cadaver donor transplantation, and may provide the first situation in which these principles can be applied to clinical trials.

Animals↗
PubMed1983

Distribution of 14C-labelled acrylamide and betaine in foetuses of rats, rabbits, beagle dogs and miniature pigs.

[14C]Acrylamide and [14C]betaine hydrochloride were administered in a single iv dose to pregnant rats, rabbits, beagle dogs and miniature pigs late in gestation (1-2 days before expected parturition). Dosages used were 10 mg/kg for rats and 5 mg/kg for the other species. The compounds were allowed to equilibrate in the animal (for 1 hr in rats and for 2 hr in the other species); the dam was then killed and the foetuses were removed by caesarean section. Each foetus was weighed and analysed for radioactivity, either by homogenization of the whole foetus (rat and rabbit) or by determining separately the radioactivity in individual organs and tissues (dog and pig). Foetal uptake of the polar compound betaine hydrochloride was much lower than that of the more lipophilic acrylamide. The sex of the foetus did not appear to affect uptake of either compound. There were no significant differences in total uptake of isotope attributable to the position of the foetus within the uterus in any of the four species given either acrylamide or betaine. Similarly, uterine position did not affect the uptake of acrylamide or betaine by individual tissues of foetal dogs or pigs. Since the distributions of 14C-labelled acrylamide and betaine hydrochloride were essentially uniform throughout a litter, it would not be necessary to sample all of the members of a litter to obtain a representative picture of foetal distribution.

Acrylamides↗
PubMed1985

Maternal-foetal distribution studies in late pregnancy. I. Distribution of [N-methyl-14C]betaine in tissues of beagle dogs and miniature pigs.

[N-Me-14C]Betaine was administered iv as a single dose (5 mg/kg) to pregnant beagle dogs and miniature pigs late in gestation. Two hr after administration of the radiolabel, when the compound was in equilibrium, the dams were killed and the foetuses were removed for determination of the radioactivity in maternal and foetal tissues. Eight litters of dogs (56 foetuses) and four litters of pigs (30 foetuses) were examined. The distribution of betaine in both species showed distinct differences between maternal and foetal tissues, indicating definite placental barriers; the placental distribution factor was estimated to be 52.3% in dogs and 97.8% in pigs. The blood/brain distribution factor was 84.6% in maternal dogs, 89% in maternal pigs, 65.7% in foetal dogs and 0% in foetal pigs. In the dog, maternal liver was the largest depot of the administered betaine, followed by foetal liver. Foetal heart, lung and kidney tissues also incorporated radiolabelled betaine. The highest concentrations of betaine in the pig were found in maternal kidney and liver.

Animals↗
PubMed1985

Maternal-foetal distribution studies in late pregnancy. II. Distribution of [1-14C]acrylamide in tissues of beagle dogs and miniature pigs.

[carbonyl-14C]Acrylamide was administered iv as a single dose (5 mg/kg) to pregnant beagle dogs and miniature pigs late in gestation. After a 2-hr equilibration period, the animals were killed and foetuses were removed for determination of the amount of radioactivity in maternal and foetal tissues. In total, six dog litters (33 foetuses) and seven pig litters (45 foetuses) were examined. In dogs, acrylamide was distributed readily to both maternal and foetal tissues with a placental distribution factor of 17.7%. The blood/brain distribution factor was insignificant (5.9%) in maternal dogs and 0% in the foetuses. Maternal liver was the largest depot of the administered acrylamide in the dog, followed by the maternal kidney. In pigs, the placental distribution factor was 31%, and the blood/brain distribution factor was insignificant in both maternal and foetal pigs. Liver and kidney of maternal pigs also contained the greatest amount of radioactivity. Although there appears to be some placental protection of the foetuses from the xenobiotic in the maternal circulation, foetal brain would be exposed to the effect of any acrylamide present in the foetal circulation, since the foetuses of both species had blood/brain distribution factors that were either small or zero, reflecting the absence of a blood-brain barrier.

Acrylamide↗
PubMed1987

Comparative tissue distribution and excretion of [1-14C]acrylamide in beagle dogs and miniature pigs.

Male beagle dogs and miniature pigs were given acrylamide in the diet for 3-4 wk at a dosage of 1 mg/kg/day. They were then given [1-14C]acrylamide as a single oral dose of 1 mg/kg. The animals were killed 6 hr or 1, 2, 4 or 14 days after administration of the radioactive compound and tissues were analysed for radioactivity. The radiolabelled material was distributed to a major extent in muscle tissue in both species (31-35% of the dose at 6 hr and 5-7% at 14 days). Although the nervous system is the primary target for acrylamide monomer toxicity, less than 1% of the administered 14C was found in the brain in both species. No neurotoxic signs were evident during the exposure period at the dosage used. Analysis of discrete areas of the brain for radioactivity revealed that the levels of penetration of [1-14C]acrylamide in brain paralleled the vascularization pattern of the tissues. Approximately 60% of the administered radiolabel was excreted in the urine in both species and smaller amounts were excreted in the faeces. However, recovery in the faeces was higher in pigs (c. 25%) than in dogs (c. 7%) and this and the considerably higher levels demonstrated in the gastro-intestinal tract of the pigs indicated that the absorption of acrylamide was more rapid and more extensive in dogs than in pigs.

Acrylamide↗