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PubMed1999

The magnitude of decrease in hepatic very low density lipoprotein apolipoprotein B secretion is determined by the extent of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibition in miniature pigs.

It has been postulated that the rate of hepatic very low density lipoprotein (VLDL) apolipoprotein (apo) B secretion is dependent upon the activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. To test this hypothesis in vivo, apoB kinetic studies were carried out in miniature pigs before and after 21 days treatment with high-dose (10 mg/kg/day), atorvastatin (A) or simvastatin (S) (n = 5). Pigs were fed a diet containing fat (34% of calories) and cholesterol (400 mg/day; 0.1%). Statin treatment decreased plasma total cholesterol [31 (A) vs. 20% (S)] and low density lipoprotein (LDL) cholesterol concentrations [42 (A) vs. 24% (S)]. Significant reductions in plasma total triglyceride (46%) and VLDL triglyceride (50%) concentrations were only observed with (A). Autologous [131I]VLDL, [125I]LDL, and [3H]leucine were injected simultaneously, and apoB kinetic parameters were determined by triple-isotope multicompartmental analysis using SAAM II. Statin treatment decreased the VLDL apoB pool size [49 (A) vs. 24% (S)] and the hepatic VLDL apoB secretion rate [50 (A) vs. 33% (S)], with no change in the fractional catabolic rate (FCR). LDL apoB pool size decreased [39 (A) vs. 26% (S)], due to reductions in both the total LDL apoB production rate [30 (A) vs. 21% (S)] and LDL direct synthesis [32 (A) vs. 23% (S)]. A significant increase in the LDL apoB FCR (15%) was only seen with (A). Neither plasma VLDL nor LDL lipoprotein compositions were significantly altered. Hepatic HMG-CoA reductase was inhibited to a greater extent with (A), when compared with (S), as evidenced by 1) a greater induction in hepatic mRNA abundances for HMG-CoA reductase (105%) and the LDL receptor (40%) (both P < 0.05); and 2) a greater decrease in hepatic free (9%) and esterified cholesterol (25%) (both P < 0.05). We conclude that both (A) and (S) decrease hepatic VLDL apoB secretion, in vivo, but that the magnitude is determined by the extent of HMG-CoA reductase inhibition.

Animals↗

PubMed1990

Hepatic circulation and oxygen supply-uptake relationships after hepatic ischemic insult during anesthesia with volatile anesthetics and fentanyl in miniature pigs.

The objective of the present study was to quantitate the effects of several anesthetics on hepatic circulation, oxygenation, and function after hepatic ischemic insult and during reperfusion. We examined the effects of different anesthetics on hepatic circulation, oxygenation, and function after hepatic ischemic insult in 28 miniature pigs weighing 20-27 kg. The preparation allowed a stepwise decrease followed by a complete cessation for 1 h of hepatic blood and oxygen supply. Immediately after the unclamping of both vessels supplying the liver and restoration of the hepatic circulation, systemic mean arterial pressure decreased to approximately 75% of preischemic values in animals anesthetized with pentobarbital and fentanyl and to 60% of preischemic values in pigs anesthetized with halothane, enflurane, or isoflurane. Total hepatic blood flow immediately returned to preischemic values without significant difference between the groups. Subsequently, hepatic oxygen delivery returned to 75%-95% of preischemic values. Hepatic oxygen uptake returned to 50%-60% of preischemic values in animals anesthetized with pentobarbital and with volatile anesthetics and up to 80% and then later to baseline values with fentanyl anesthesia. Lactate uptake by the liver returned to preischemic values only in animals given fentanyl or isoflurane but remained at approximately 50% of preischemic values during enflurane and 20%-40% during halothane and pentobarbital anesthesia. Thus, the study indicates that both isoflurane and fentanyl anesthesia provide more protection from ischemic insult than do halothane, enflurane, or pentobarbital anesthesia.

Anesthetics↗

PubMed1989

Length-tension relationships of masseter and digastric muscles of miniature swine during ontogeny.

At incremental whole muscle lengths, active isometric and passive elastic forces were recorded from the masseter and digastric muscles of anaesthetized miniature pigs (Hanford) weighing 2.0-20.0 kg. Wet muscle mass and maximum tetanic tension values for masseter exceed those for digastric and increase more rapidly with body mass (age). At any body mass, masseter exceeds digastric in the ratio of optimum length (that length at which maximum tetanic tension is produced) to in situ muscle length (that length which corresponds to the jaw in a closed position) and the proportion of passive tension comprising total (passive plus active) tension. Passive elastic tension begins to rise in masseter at lengths as short as 87% of optimum (in younger pigs). In digastric, passive tension is absent until the muscle is stretched to a length slightly longer than optimum in younger pigs but occurs at shorter lengths in older pigs. Contractile properties explain functional differences between masseter and digastric more clearly than they explain ontogenetic changes in either muscle. The behavioural transition from infant suckling to adult mastication of solid food is best characterized by a disproportionate increase in mass (and force) of the masseter, relative to digastric, and increased reliance upon active (rather than passive) tension.

Aging↗

PubMed1994

Body and organ growth of the developing Hormel-Hanford strain of male miniature swine.

As part of a larger study designed to characterize the early developmental stages of the Hormel-Hanford strain miniature pig, whole body, brain, kidney, liver, pancreas and spleen from male animals were examined for weight increases from one to 196 days, the approximate age of maturity. At 196 days, body weights had increased to 82.5 times the weight at day 1; increases in organ weights were greatest for spleen, less and similar for kidney, liver and pancreas, and the least for brain. Little change in relative organ weights was noted, except for the brain where an almost steady decrease occurred starting from 7 days after birth.

Animals↗

PubMed1994

Ornithine decarboxylase, fatty acid synthetase, and lipid levels in selected organs of the postnatal developing male miniature pig.

Ornithine decarboxylase (ODC) and fatty acid synthetase (FAS) activities were determined in tissues from male neonate and juvenile miniature swine (Hormel-Hanford strain) at various ages. ODC activity was measured in liver, brain, kidney, pancreas, and spleen at one day and at 1, 4, 8, 12 and between 24 and 32 weeks. Hepatic FAS activity, total lipid, triglyceride, and total cholesterol were measured at 2, 8, 16, and 32 weeks. Generally, tissue ODC activity was highest in the spleen at all ages. Three postnatal patterns of ODC activity were observed for the different organs. The mean values of FAS activity, total lipid, and cholesterol were highest at 8 weeks compared to other sampling periods.

Animals↗

PubMed2005

Immunolocalization of steroidogenic enzymes P450scc, 3betaHSD, P450c17, and P450arom in Göttingen miniature pig testes.

The objective of this study was to investigate immunolocalization of steroidogenic enzymes in Göttingen miniature (GM) pig testes. Testes of 6 adult GM pigs were obtained in September 1996 (n=2), February (n=2) and June (n=2), 1997. Steroidogenic enzymes were immunolocalized using polyclonal antisera raised against bovine adrenal cholesterol side-chain cleavage cytochrome P450 (P450scc), human placental 3beta-hydroxysteroid dehydrogenase (3betaHSD), porcine testicular 17alpha-hydroxylase cytochrome P450 (P450c17), and human placental aromatase cytochrome P450 (P450arom). Histologically, all types of spermatogenic cells including mature-phase spermatozoa in seminiferous tubules were observed in all testes throughout the year. Moreover, P450scc, 3betaHSD, P450c17and P450arom were identified in Leydig cells but not in Sertoli cells of all testes. These results suggested that adult GM pig testes have the ability to produce germ cells throughout the year, and the synthesis of progestin, androgen and estrogen occurs in the Leydig cells of GM pig testes.

3-Hydroxysteroid Dehydrogenases↗

PubMed2006

Genetic characteristics of inbred Wuzhishan miniature pigs, a native Chinese breed.

The Wuzhishan miniature pig originates from Hainan Island, P. R. China, and is considered useful for medical and veterinary research due to its small size; a mature adult weights less than 25 kg. To reveal the genetic characteristics of this breed, the genetic polymorphism in 4 inbred strains was estimated using 30 microsatellite genes, multiplex polymerase chain reaction, and gene scanning. The average number of alleles at the 30 marker loci was 8.300, 4.533, 6.700, and 7.433, respectively. The polymorphism information content was 0.632, 0.507, 0.653, and 0.691, respectively. The average homozygosity in these strains was 0.537, 0.546, 0.549, and 0.520, respectively. These results indicate a relatively high degree of heterozygosity, perhaps becaquse these strains were inbred for 3 generations. Therefore, a long-term inbred breeding program should be conducted for Wuzhishan pigs to establish an experimental model.

Animals↗

PubMed1990

Suppression of MLR and DTH responses in miniature swine by pretreatment with ultraviolet (UV)-irradiated peripheral blood lymphocytes.

Ultraviolet (UV)-irradiation of peripheral blood lymphocytes (PBL) of miniature swine prevented them from initiating proliferative responses in allogeneic mixed lymphocyte reactions (MLR). When pigs were given 4 weekly intravenous transfusions of UV-irradiated allogeneic donor PBL differing in major histocompatibility (MHC), PBL of recipient pigs progressively responded less vigorously to donor PBL in MLRs over the treatment period. These pigs did not produce anti-donor PBL antibody. Pigs treated with UV-irradiated PBL also had negligible delayed type hypersensitivity (DTH) responses to donor PBL at the end of the treatment period. In contrast, pigs receiving injections of untreated allogeneic PBL gave strong DTH responses to donor PBL, high proliferation in MLRs with donor PBL and all produced anti-donor PBL antibody.

Animals↗

PubMed2003

Miniaturized three-dimensional endoscopic imaging system based on active stereovision.

A miniaturized three-dimensional endoscopic imaging system is presented. The system consists of two imaging in channels that can be used to obtain an image from an object of interest and to project as tructured light onto the imaged object to measure the surface topology. The structured light was generated with a collimated monochromatic light source and a holographic binary phase grating. The imaging and projection channels were calibrated by use of a modified pinhole camera. The surface profile was extracted by use of triangulation between the projected feature points and the two channel ofthe endoscope. The imaging system was evaluated in three-dimensional measurements of several objects with known geometries. The results show that surface profiles of the objects with different surfaces and dimensions can be obtained at high accuracy. The in vivo measurements at tissue sites of human skin and an oral cavity demonstrated the potential of the technique for clinical applications.

Depth Perception↗

PubMed2004

Multireflection pumping concept for miniaturized diode-pumped solid-state lasers.

An innovative pump concept for diode-pumped, solid-state lasers is introduced as an example for an Er:YSGG laser, permitting its miniaturization. Embedded in a multireflective pump cavity, the laser crystal is simultaneously side and end pumped. Specially calculated and shaped deflecting optics distribute the coaxially input pumping light homogeneously over the lateral surface of the crystal, therefore reducing the size of the laser head, including the optical resonator, to a length of 27.5 mm and an outside diameter of 12.5 mm. The differential efficiency achieved is between 8.7% and 24%. The laser emits energy of 15.7 mJ at an absolute efficiency of 9.1% and a repetition rate of 4 Hz.

Equipment Design↗

PubMed2005

In vivo fiber-optic confocal reflectance microscope with an injection-molded plastic miniature objective lens.

For in vivo optical diagnostic technologies to be distributed to the developed and developing worlds, optical imaging systems must be constructed of inexpensive components. We present a fiber-optic confocal reflectance microscope with a cost-effective injection-molded plastic miniature objective lens for in vivo imaging of human tissues in near real time. The measured lateral resolution is less than 2.2 microm, and the measured axial resolution is 10 microm. Confocal images of ex vivo cervical tissue biopsies and in vivo human lip taken at 15 frames/s demonstrate the microscope's capability of imaging cell morphology and tissue architecture.

Cervix Uteri↗

PubMed2004

Miniaturized two-photon microscope based on a flexible coherent fiber bundle and a gradient-index lens objective.

We present a miniature, flexible two-photon microscope consisting of a fused coherent optical fiber bundle with 30,000 cores and a gradient-index lens objective. The laser focus of a standard two-photon laser-scanning microscope was scanned over the entrance surface of the fiber bundle, resulting in sequential coupling into individual cores. Fluorescent light was detected through the fiber bundle. Micrometer-sized fluorescent beads and pollen grains were readily resolved. In addition, fluorescently labeled blood vessels were imaged through the fiber bundle in rat brain in vivo.

Animals↗

PubMed2007

Miniature near-infrared dual-axes confocal microscope utilizing a two-dimensional microelectromechanical systems scanner.

The first, to our knowledge, miniature dual-axes confocal microscope has been developed, with an outer diameter of 10 mm, for subsurface imaging of biological tissues with 5-7 microm resolution. Depth-resolved en face images are obtained at 30 frames per second, with a field of view of 800 x 100 microm, by employing a two-dimensional scanning microelectromechanical systems mirror. Reflectance and fluorescence images are obtained with a laser source at 785 nm, demonstrating the ability to perform real-time optical biopsy.

Computer Systems↗

PubMed2002

[Miniature assistance module for robot-assisted heart surgery].

During the robotic enhanced minimally invasive cardiac surgery the approach to and the space for handling instruments in the operating field are usually reduced, compared to the conventional surgery. Additional well knewn problems are the restricted capability available for accessories into and out of the closed chest and the limited assistance during the cardiac procedure. This paper is presenting two solutions of Miniature Modules for supporting the surgeon inside the closed chest. A self-sufficient Cargo Module is developed as a transportation and depot device. It provides an "inside equipment store" for the surgeon. With the Assist Module the surgical equipment, tissue and vessels can be positioned on a desired place in the operating field. This module provides the surgeon an "assistant" inside the closed chest.

Coronary Artery Bypass↗

PubMed2002

Miniaturized instrument systems for minimally invasive diagnosis and therapy.

Microsystems technologies allow to considerably improve the functionality of existing medical instruments and produce novel devices. Using extremely miniaturized operation systems based on micro-technically processed nickel-titanium alloys, minimally invasive therapeutic interventions can be accomplished in the most sensitive parts of the human body. This has not been possible so far. Fields of use presently comprise among others minimally invasive surgery, endoscopic neurosurgery, interventional cardiology, gynaecology, urology, and ophthalmology.

Alloys↗

PubMed2002

Miniaturized module for the wireless transmission of measurements with Bluetooth.

The wiring of patients for obtaining medical measurements has many disadvantages. In order to limit these, a miniaturized module was developed which digitalizes analog signals and sends the signal wirelessly to the receiver using Bluetooth. Bluetooth is especially suitable for this application because distances of up to 10 m are possible with low power consumption and robust transmission with encryption. The module consists of a Bluetooth chip, which is initialized in such a way by a microcontroller that connections from other bluetooth receivers can be accepted. The signals are then transmitted to the distant end. The maximum bit rate of the 23 mm x 30 mm module is 73.5 kBit/s. At 4.7 kBit/s, the current consumption is 12 mA.

Amplifiers, Electronic↗

PubMed1988

Insulin-like growth factors in the Göttinger miniature-pig.

IGF I was determined by a radioimmunoassay and IGF II by a radioreceptorassay in 20 Göttinger miniature (mini)-pigs and 13 domestic pigs of different weight and age. Immunoreactive IGF I serum levels of mini-pigs were similar to those of domestic pigs in corresponding age-classes (150-250 and 100-270 micrograms/l, respectively). No differences were detectable between receptor-reactive IGF II serum levels in mini-pigs (150-200 micrograms/l) and domestic pigs (110-270 micrograms/l) nor did the biological insulin-like activities (measured in the rat fat cell assay) differ in mini- and domestic pigs (81-100 and 71-98 mU insulin/l, respectively). IGF I and IGF II decreased drastically after hypophysectomy in one of the mini-pigs. Intravenous bolus injections of 30 micrograms/kg of recombinant human IGF I in 4 mini-pigs caused a similar degree of hypoglycemia (nadir of blood glucose 1.33 +/- 0.61 mmol/l) as 0.15 IU insulin/kg, followed by a sharp growth hormone peak. We conclude that the marked difference between mini- and domestic pigs regarding body size is unrelated to serum levels of IGF I and II, a lack of response of tissues to IGF I or a reduced growth hormone secretory capacity in the mini-pig.

Animals↗

PubMed1988

Influence of SLA haplotype on ovulation rate and litter size in miniature pigs.

Systemic blood was collected from and surgery performed on sows of 3 strains of miniature swine bred for specific SLA (swine MHC) haplotypes (a, c and d) from Day 2 to Day 6 after mating (first day of mating = Day 0). Ovulation rate was determined by counting corpora lutea and embryos were flushed from the uterus. Progesterone, oestradiol-17 beta and oestrone were quantitated in blood plasma and uterine flushings by RIA. SLAd/d females had a higher ovulation rate than SLAa/a or SLAc/c females (11.50 +/- 0.87 vs 9.11 +/- 0.68 and 8.17 +/- 0.83, respectively; P less than 0.01). Oestrone was higher than oestradiol-17 beta in systemic plasma (56.5 +/- 6.4 vs 33.0 +/- 4.7 pg/ml, P less than 0.01) while oestradiol-17 beta was higher than oestrone in uterine flushings (19.8 +/- 1.4 vs 14.9 +/- 1.5 pg/horn, P less than 0.10). Systemic progesterone concentration was correlated with day after mating (r = 0.93, P less than 0.01). There was no effect of haplotype on any of the hormone concentrations measured. Litter size was analysed from 99 matings amongst SLAa/a, SLAa/c, SLAa/d, SLAd/c and SLAd/d sires and dams. Litter size from -/d and d/d sows or from d/d boars were larger (P less than 0.05) than for all other matings. Although ovulation rate was higher in SLAd/d sows, the significant effect of sire SLA genotype on litter size suggests an additional effect of the d haplotype on embryonic survival.

Animals↗