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At least 1,027 records · Page 57Linked to original sources
PubMed2005

[Uterine artery embolization using gelatin sponge in a miniature pig: a study of arterial size and the distribution of embolic materials].

Uterine artery embolization using gelatin sponge particles was performed in a miniature pig, and the distribution of the particles was investigated. The particles spread in the cervix and proximal portion of the left horn. Histological study revealed embolic material in both the myometrium and endometrium. Several particles were found even in arteries smaller than 100 microm in diameter in the endometrium. Further studies should address the risks of gelatin sponge particles in the peripheral arteries of the uterine endometrium, as they may induce inflammatory processes and evoke complications including infection and menopause.

Animals↗
PubMed1992

Selective breeding of miniature swine leads to an increased rate of acceptance of MHC-identical, but not of class I-disparate, renal allografts.

Previous work from this laboratory demonstrated that tolerance to MHC-identical or class I-disparate renal allografts develops in approximately one third of miniature swine without exogenous immunosuppression. A back-cross study indicated that rejection of MHC-identical transplants due to minor Ag was controlled by one or possibly two non-MHC-linked, autosomal dominant Ir genes. According to this hypothesis, and assuming complete penetrance, graft acceptors would be homozygous recessive at the relevant Ir loci, as would their offspring. Alternatively, if the gene(s) were incompletely penetrant, then two acceptors could give rise to a rejector. However, a high rate of MHC-identical graft acceptance would still be expected in the offspring of acceptors even if the Ir gene(s) were incompletely penetrant. To test this hypothesis and to obtain a higher frequency of acceptor animals for studies of tolerance, a program of selective breeding of renal allograft acceptors was begun. In the present paper, we assess the effect of selective breeding on renal graft acceptance. The analysis indicates a marked increase in the rate of MHC-identical graft acceptance, from 27.3% (n = 24) for the earliest of the four chronologic subgroups assessed to 64.5% (n = 33) for the most recent subgroup (p less than 0.0001). Calculations of kinship revealed that the increased acceptance of MHC-identical grafts was not the result of differences between acceptors and rejectors in donor/recipient consanguinity. Class I-disparate grafts (n = 128) were similarly stratified chronologically and compared. Unlike MHC-identical grafts, the rate of acceptance of class I-disparate grafts has not changed over time. We conclude that rejector/acceptor status with respect to class I MHC incompatibility is determined by genetic factors in addition to those that control responses to minor antigen incompatibilities only.

Animals↗
PubMed2006

Voltage-dependence of miniature inhibitory postsynaptic current frequency and amplitude in tectal neurons of Xenopus.

Experiments were performed to study the voltage-dependence of miniature inhibitory postsynaptic current (mIPSC) frequency and amplitude using patch-clamp technique with whole cell recording in optic tectal slices of Xenopus. The following results have been observed. (1) When the membrane potentials of a neuron were depolarized or hyperpolarized stepwise from a resting potential via recording pipette to inject a DC current, the frequency and/or amplitude of mIPSCs increased or decreased respectively. The frequency of mIPSCs increased gradually with depolarizing membrane potential and it attained to the maximum as the membrane potential was held at +10 mV. (2) The amplitude increased slightly as the neuron was depolarized. When the depolarization of membrane potential reached -30 or -40 mV, the amplitudes of mIPSCs were maximal. Further depolarization resulted in a decrease of amplitude. Meanwhile, the large mIPSCs appeared when the membrane potential depolarized to a range between -20 mV and +10 mV. (3) With Ca(2+)-free bath solution, the frequency and amplitude of mIPSCs also increased stepwise progressively on depolarization of membrane potential, but the increase was less marked as corresponding value in normal saline perfusion. (4) When the [K(+)](o) in bath solution increased, the frequency of mIPSCs decreased markedly and the amplitude of mIPSCs decreased slightly. If the external K(+) concentration increased further to higher than 20 mmol/L, the neuron produced a marked slow inward or outward membrane current. The possible mechanism underlying the voltage-dependence of mIPSC frequency and amplitude is discussed briefly.

Animals↗
PubMed2006

[Effect of single dose irradiation to parotid gland on the structured and function changes of bilateral parotid glands in miniature pig].

OBJECTIVE: To evaluate the effects of a solitary megadose protocol of ionizing radiation (IR) to parotid gland on the structured and function changes of bilateral parotid glands in miniature pig. METHODS: Fourteen minipigs were subjected to either 15 or 20 Gy to one parotid gland with a linear accelerator, while another four minipigs served as non-IR controls. Salivary flow rates and salivary chemistries were measured pre-IR, and 4 and 16 weeks post-IR. A quantitative assessment of gland weight and acinar area, and detailed serum chemistry and hematological analyses, were also performed. RESULTS: Parotid gland weights were significantly decreased in the 15 and 20 Gy groups at 4 and 16 weeks post-IR. The acinar cell area in glands of both IR groups was significantly reduced. Parotid flow rates decreased by 60% with 15 Gy at 16 weeks post-IR. In the 20 Gy group, salivary flow rates were reduced by 80% at 16 weeks post-IR. Additionally, parotid flow rates significantly reduced in contralateral glands with 20 Gy at 16 weeks, while structure and weight did not changes in parotid glands. CONCLUSION: Structural changes in salivary gland parenchyma occurred relatively early after IR, while the alterations in salivary output were relatively delayed. Further, reductions in salivary flow were not proportional to acinar cell area loss. There isn't a significant structured change of contralateral glands, but significant reduction of parotid flow rate at this time.

Animals↗
PubMedDate not supplied

Miniature membrane oxygenator for use in neonatal ECMO.

A new miniature membrane oxygenator (Kuraray KMO, size, 0.3 m2, with a priming volume of 47 ml, compliance of less than 0.1 ml/100 mmHg, and pressure loss of 45 mmHg) with improved gas transfer and mechanical durability was developed and tested. The membrane material is a hollow fiber double layer polyolefin. The testing procedures determined by the AAMI were followed, and the results showed improved O2 and CO2 transfer (70 ml/min and 55 ml/min, respectively). Hemolysis was within acceptable limits, and plasma leakage was undetectable after 7 days of perfusion. Clinical study demonstrated satisfactory performance.

Carbon Dioxide↗
PubMed1991

Clinical validation of a miniature nuclear probe system for continuous on-line monitoring of cardiac function and ST-segment.

A new, miniature cesium iodide/photodiode nuclear probe (the "Cardioscint") has been developed for continuous on-line measurement of left ventricular function and the ST-segment. Ejection fraction (EF) measurements in 77 patients were compared with gated equilibrium radionuclide ventriculograms. The probe was positioned over the left ventricle by first using a blind positioning algorithm and then by using the gamma camera. Background was measured both manually and automatically. There was good correlation between probe (positioned blind) and gamma camera EF with both manual (r = 0.80, n = 65) and automatic (r = 0.78, n = 66) backgrounds. Use of the gamma camera did not significantly alter the results. Correlation between the probe stroke counts and thermodilution-derived stroke index during atrial pacing in six subjects was also satisfactory (r = 0.69, n = 102). Thus, the Cardioscint is able to provide a reliable estimate of EF and can track rapid changes in cardiac volumes.

Cardiac Pacing, Artificial↗
PubMed1991

The effect of exercise on plasma lipids and LDL subclass metabolism in miniature swine.

The effects of exercise on plasma lipids and lipoproteins, high density lipoprotein (HDL) subclass cholesterol levels, and low density lipoprotein (LDL) subclass composition and metabolism were studied in Yucatan miniature swine following 2 yr of training. The exercise protocol produced significant training effects. Post-heparin lipolytic activity was also significantly increased. Although plasma cholesterol and triglycerides did not differ significantly (P = 0.08) between the exercised and control groups, multivariate analysis indicated a strong association between lipoprotein lipase (LPL) and HDL2-C (P less than 0.0001). Although HDL-C levels rose only slightly (P less than 0.09) with exercise, a significant shift was noted in the distribution of cholesterol from the HDL3 to the HDL2 fractions, perhaps mediated by the substantial increase in LPL activity. Exercise had little effect on the chemical composition of the major lipoprotein classes; however, the triglyceride content of the lighter LDL1 subclass was significantly reduced. In the more dense LDL2 subclass, exercise resulted in a significant decrease in triglycerides concomitant with a significant increase in free cholesterol levels. In contrast with the small reductions in fractional catabolic rates (FCR) in either subclass, production rates of the exercised group were reduced, which accounted for the reduction in LDL subclass pool size. These data indicate that exercise produces subtle but significant changes in lipoprotein metabolism that have been previously associated with reduced risk of atherosclerosis.

Animals↗
PubMed1990

Fetal pancreas transplantation in miniature swine. IV. Suppression of DTH and MLR responses by treatment with ultraviolet light-irradiated peripheral blood lymphocytes.

Irradiation of peripheral blood lymphocytes of miniature swine with ultraviolet light prevented them from initiating proliferative responses in allogeneic mixed lymphocyte reactions and also reduced IL-2 production in these MLRs. When pigs were injected in a series of 4-5 weekly transfusions with UV-irradiated allogeneic PBL differing at the MHC, PBL of recipient pigs progressively responded less strongly to donor PBL in MLRs over the treatment period. These pigs also gave negligible delayed-type hypersensitivity responses to donor PBL at the end of the treatment period. Of the seven UV-irradiated PBL-treated pigs, four produced no antidonor PBL antibody and three produced antibody. Serum from the three antibody-producing pigs also suppressed MLRs of unrelated PBL. By contrast, pigs that received a series of injections of untreated allogeneic PBL gave strong DTH responses to donor PBL and heightened proliferation in MLRs with donor PBL, and all produced antidonor PBL antibody.

Animals↗
PubMed1990

Experimental frost-bite in Hanford Miniature Swine. III. Sweat gland changes.

Frost-bite was produced in five Hanford Miniature Swine by exposure to -75 degrees C air for 1, 3, 5, 10 or 20 min. Biopsies were taken at 0, 3, 6, 12, 24 and 48 h and 1, 2 and 15 weeks. Sweat glands were evaluated microscopically and graded: 0, no change to 5, severe change. Sweat gland changes were mild by 1 h and moderate by 24 h for all freeze groups, except the 1-min freeze group. Severe morphological changes were of two types: degeneration/necrosis and squamous metaplasia. These changes suggest that hyperhidrosis, as a sequel to frost-bite, may be more subjective than real and that squamous cell carcinoma, as a delayed sequel to frost-bite, could originate from sweat glands as well as from the epidermis.

Animals↗
PubMed1990

A miniaturized vitrectomy system for vitreous and retinal biopsy.

The author has developed a miniaturized vitrectomy system and its accessories with the size of a 23-gauge needle. The hand-piece can be inserted inside the eye through a Ziegler knife track. This instrument can be used for "atraumatic" removal of vitreous biopsy specimens and for removal of small pieces of retina. The system also seems to have application in vitreous surgery in premature infants' eyes.

Biopsy↗
PubMedDate not supplied

[Diffusion of O2 in the normal and the ischemic retina of miniature pigs].

Transretinal PO2 profiles were recorded during normoxia and hyperoxia in normal and ischemic retinal territories in anesthetized miniature pigs using double barrelled recess type microelectrodes. In normoxia and hyperoxia the PO2 in the normal territory decreased from the inner retina and the choroid towards the mid-retina, indicating that the choroid cannot supply O2 to the whole normal retina. Preretinal and transretinal PO2 measurements in ischemic territories following a laser occlusion of a retinal branch vein demonstrated that in normoxia the direction of PO2 gradients prevents O2 diffusing from the choroid to reach the inner retina. This explains why the ischemic territories are hypoxic. In the contrary, during hyperoxia the intraretinal PO2 gradient indicates an O2 flux from the choroid to the inner retina resulting to marked preretinal PO2 increase at the affected territories. We proposed the hypothesis that in the ischemic retinas the hyperoxia does not induce a rise of the O2 consumption of the outer retina. Hence hyperoxia could be a useful tool to restore the oxygenation of the inner hypoxic retinal layers.

Animals↗
PubMed1990

Electroejaculation and artificial insemination in Vietnamese potbellied miniature pigs.

A 15-month-old Vietnamese miniature boar was examined because of suspected infertility. A breeding soundness examination was conducted, using electroejaculation under anesthesia for semen collection. Semen values were normal despite a subpubic location of the testes. Artificial insemination of a gilt with extended semen resulted in the birth of a litter 111 days later. Vietnamese potbellied boars have small and sometimes nearly undetectable scrotal pouches, which may cause the producer to question the fertility of the boars.

Animals↗
PubMed1990

[Relationship between body mass, brain mass and craniometric parameters in the miniature pig Mini-Lewe].

The relations between skull measurements, brain mass, and body mass were investigated in 30 female miniature pigs, being 6 month old. The relatively low correlation coefficients between the variables indicate a high variability in skull shape. We found an allometric exponent of 0.236 for the relation between brain and body mass with a coefficient of determination of 0.29. Both measurements show a highest correlation with the arcus zygomaticus width, which shows close relations with the occipital height and condylobasal length.

Animals↗
PubMed1989

Influence of major histocompatibility genes on serum hemolytic complement activity in miniature swine.

Total serum hemolytic complement (CH50) activity was determined for 3 semi-inbred strains of miniature swine (SLAa, SLAc, and SLAd) and 1 recombinant strain SLAg (ABCcDd), each homozygous for a distinct major histocompatibility complex haplotype. Initial determination was made at 8 weeks of age, prior to standardized immunization, the second at age 12 weeks, after immunization. Analysis of variance was by least-squares method, using a linear model on data from 33 litters by 14 sires and 16 dams. Analysis of variance indicated that the combined effects of haplotype, sire, dam, litter, and gender accounted for 47.63% of the total variation in preimmunization CH50 values. Dam (P less than or equal to 0.06) and litter (P less than or equal to 0.03) significantly influenced preimmunization complement activity. Although swine leukocyte antigen (SLA) haplotype was not significant in the model, least-squares mean comparisons between haplotypes suggested that ac, dg, and gg pigs tended to have comparatively low preimmunization CH50 values. The model did not account for significant variability in postimmunization CH50 values, but least-squares means indicated that dd, dg, and gg haplotypes tended to have lower values than did other haplotypes tested. Mean CH50 units for 8- and 12-week-old pigs were 41.32 +/- 20.49 and 59.50 +/- 54.35, respectively. There was a significant difference (P less than or equal to 0.001) in CH50 activity between 8- and 12-week-old pigs associated with immunization, because CH50 of nonimmunized controls did not differ at 8 and 12 weeks.

Analysis of Variance↗
PubMed1989

A model of postprandial hyperinsulinemia in miniature swine.

This report describes a new animal model of postprandial hyperinsulinemia (PPH) in adult miniature swine that consume a diet simulating that of affluent Western societies. Two progressive levels of PPH were induced experimentally by injecting subcutaneously low and high doses of purified porcine insulin without causing acute detrimental clinical effects or significant biological effects on total serum cholesterol, sodium and potassium concentrations, mean arterial blood pressure, or heart rate. Physiologic postprandial increments in total serum triglyceride concentrations were inhibited by experimentally-induced PPH. With this model, the in vivo effects of homologous PPH can be studied in a dose-responsive manner. Areas of potential research use of this model include study of the chronic effects of PPH on lipoprotein metabolism, the development of atherosclerosis and diabetes mellitus, and the association with regional body fat distribution and metabolism.

Animals↗
PubMed1989

Effects of dipyridamole on the cardiovascular response to +Gz stress in miniature swine.

Eight conscious female miniature swine experienced acceleration levels of 3, 5, and 7 +Gz before and after infusion of dipyridamole (1-2 mg.kg-1). Each animal was instrumented to measure ECG, heart level arterial pressure (AP), eye level arterial pressure (ELBP), left arterial pressure (LAP), heart rate (HR), and regional tissue blood flows. Each was also fitted with an abdominal anti-G suit which automatically inflated. Dipyridamole infusion had no direct effect on HR or LAP but AP was significantly reduced. All cardiovascular responses to +Gz were qualitatively similar before and after dipyridamole. Tachycardia always occurred. AP and CNS blood flow were maintained better prior to dipyridamole and AP always fell in proportion to acceleration intensity. +Gz was generally associated with increased blood flow to respiratory muscles and heart, decreased blood flow throughout the viscera and to the eyes. ELBP paralleled AP, but was always lower in direct proportion to the +Gz level. We conclude that dipyridamole reduces arterial pressure thus compromising the ability of the animal to sustain cerebral perfusion pressure (ELBP) during +Gz.

Animals↗
PubMed1989

[Myeloid leukemia in a Göttingen miniature swine].

After giving a short review of the different types of leukosis in the pig a leukosis in a Göttingen miniature breeding sow is described. The clinical symptoms were nonspecific, the pathomorphological signs were characterized by hepato- and splenomegaly and leukotic changes in kidneys and lymph nodes. By means of hematologic examinations a chronic myeloic leukosis could be diagnosed.

Animals↗