Matrix Anisotropy Promotes a Transition of Collective to Disseminated Cell Migration via a Collective Vortex Motion.

Cells detached and disseminated away from collectively migrating cells are frequently found during tumor invasion at the invasion front, where extracellular matrix (ECM) fibers are parallel to the cell migration direction. However, it remains unclear how anisotropic topography promotes the transition of collective to disseminated cell migration. This study applies a collective cell migration model with and without 800 nm wide aligned nanogrooves parallel, perpendicular, or diagonal to the cell migration direction. After 120 hour migration, MCF7-GFP-H2B-mCherry breast cancer cells display more disseminated cells at the migration front on parallel topography than on other topographies. Notably, a fluid-like collective motion with high vorticity is enhanced at the migration front on parallel topography. Furthermore, high vorticity but not velocity is correlated with disseminated cell numbers on parallel topography. Enhanced collective vortex motion colocalizes with cell monolayer defects where cells extend protrusions into the free space, suggesting that topography-driven cell crawling for defect closure promotes the collective vortex motion. In addition, elongated cell morphology and frequent protrusions induced by topography may further contribute to the collective vortex motion. Overall, a high-vorticity collective motion at the migration front promoted by parallel topography suggests a cause of the transition of collective to disseminated cell migration.

Genetic Association between Farrowing Rates and Swine Leukocyte Antigen Alleles or Haplotypes in Microminipigs.

We have previously reported specific swine leukocyte antigen (SLA) haplotype associations with significant effects on several reproduction performance traits in a highly inbred miniature pig population of Microminipigs (MMPs). In this study, to clarify the effects on farrowing rates of SLA similarity between mating partners in the MMP population, we compared the farrowing rates as a measure of reproductive success after 1063-cumulative matings among the following three groups of mating partners: (1) completely sharing SLA class I or class II haplotypes or alleles between partners (CS), (2) only one sharing the haplotypes or alleles (OS), and (3) non-sharing the haplotypes or alleles (NS). Average farrowing rates in CS groups consisting of completely sharing SLA class II haplotypes or DRBI and DQB1 alleles were lowest in the three groups. Moreover, lower farrowing rates were indicated in mating pairs with smaller amino acid pairwise genetic distances of SLA-1, SLA-3, DRB1 and DQB1 alleles between the pairs. These results suggested that the dissimilarity of SLA class I and class II alleles between mating partners markedly improved reproductive performance; therefore, SLA alleles or haplotypes are potentially useful genetic markers for the selection of mating pairs in breeding programs and epistatic studies of reproductive traits of MMPs.

A Microfabricated Pistonless Syringe Pump Driven by Electro-Conjugate Fluid with Leakless On/Off Microvalves.

In contrast to microfluidic devices, bulky syringe pumps are widely used to deliver a small amount of solution with high accuracy. Miniaturizing the syringe pump is difficult due to the scale effect in the microscale where the friction of the piston-cylinder is dominant and there are few high-power microactuators. To solve these problems, an on-chip microsyringe pump without mechanical sliding parts and with high power sources is proposed. The microsyringe pump utilizes the interface between water and oil (electro-conjugate fluid, ECF) instead of a piston and an electrohydrodynamic (EHD) flow driven by ECF in place of a linear actuator. ECF as a functional fluid has two capabilities: a) making the water-oil interface in microchannels and b) generating an active ECF flow at an applied voltage to withdraw and infuse aqueous solution by the interface. To control the flow direction, ECF-driven leakless on/off microvalves are also integrated. It is demonstrated that the proposed ECF microsyringe pump synchronized with the ECF on/off microvalves can control the withdrawing and infusing of aqueous solution with high resolution and precision. The experiments prove the feasibility of the microsyringe pump to be embedded as a module for the precise and linear control of flow rates in microfluidic devices.

Stillbirth rates and their association with swine leucocyte antigen class II haplotypes in Microminipigs.

OBJECTIVE: Microminipig (MMP) is a miniature pig with an extra small body size for experimental use. In the present study, the occurrence of stillbirths and their genetic association with swine leukocyte antigen (SLA) class II haplotypes were evaluated in a population of MMPs. METHODS: The occurrences of stillbirth and genetic association with SLA class II haplotypes using 483 stillborn and 2,246 live piglets, and their parents were compared among the three groups of newborn piglet litters; an all stillborn (AS) group consisting of only stillborn piglet litters, a partial stillborn (PS) group consisting of stillborn and live piglet litters, and an all alive (AA) group consisting of only live piglet litters. RESULTS: The incidence of stillborn piglets was 483/2,729 (17.7%). Distributions of litter sizes, numbers of stillborn piglets in a litter, parities, and gestation periods were distinct among the three groups. The frequencies of low resolution haplotype (Lr)-0.7 or Lr-0.23 were higher in the AS group than in the PS or AA groups. In sires, the frequency of Lr-0.7 associated with the AS group was significantly higher in the AS group than with the AA group. In dams, the frequency of Lr-0.23 was significantly higher in the AS group than in the PS or AA groups, whereas the frequency of Lr-0.7 was not significantly different. CONCLUSION: The incidence of stillborn piglets in MMPs appears to be higher than those in other pig breeds. Several traits related with stillbirths such as the number of stillborn piglets and parities of the AS group were different from those of the PS and AA groups. Specific SLA class II haplotypes were associated significantly with a high incidence of stillbirths and could be used as genetic markers to adopt breeding strategies to lower the rate of stillbirth in MMPs.

Preparation and characterization of monoclonal antibodies recognizing two CD4 isotypes of Microminipigs.

Cluster of differentiation 4 (CD4) molecule expressed on the leukocytes is known to function as a co-receptor for class II major histocompatibility complex (MHC) binding to T cell receptor (TCR) on helper T cells. We previously identified two CD4 alleles (CD4.A and CD4.B) in a Microminipig population based on nucleotide sequencing and PCR detection of their gene sequences. However, CD4.B protein expression was not examined because of the unavailability of a reactive antibody to a CD4.B epitope. In this study, we have produced two swine-specific monoclonal antibodies (mAbs) against CD4.B molecules, one that recognizes only CD4.B (b1D7) and the other that recognizes both the CD4.A and CD4.B alleles (x1E10) and that can be used to distinguish CD4 T cell subsets by flow cytometry and immunohistochemistry. Using these two mAbs, we identified CD4.A and CD4.B allele-specific proteins on the surface of CD4.A (+/+) and CD4.B (+/+) T cells at a similar level of expression. Moreover, stimulation of peripheral blood mononuclear cells (PBMCs) derived from CD4.A (+/+) and CD4.B (+/+) swine with toxic shock syndrome toxin-1 (TSST-1) in vitro similarly activated both groups of cells that exhibited a slight increase in the CD4/CD8 double positive (DP) cell ratio. A large portion of the DP cells from the allelic CD4.A (+/+) and CD4.B (+/+) groups enhanced the total CD4 and class I swine leukocyte antigen (SLA) expression. The x1E10 mAb delayed and reduced the TSST-1-induced activation of CD4 T cells. Thus, CD4.B appears to be a functional protein whose expression on activated T cells is analogous to CD4.A.

Nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology.

In this study, we report nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology. With the aim of defining sophisticated Nafion nanostructures with highly ionic conductivity, fabrication parameters such as Nafion concentration and curing temperature were optimized. By increasing curing temperature and Nafion concentration, we were able to control the replication fidelity of Nafion nanopatterns when copied from a PDMS master mold. We also found that cross-sectional morphology and ion current density of nanopatterned Nafion strongly depends on the fabrication parameters. To investigate this dependency, current-voltage analysis was conducted using organic electrochemical transistors (OECT) overlaid with patterned Nafion substrates. Nanopatterned Nafion was found to allow higher ion current densities than unpatterned surfaces. Furthermore, higher curing temperatures were found to render Nafion layers with higher ion/electrical transfer properties. To optimize nanopattern dimensions, electrical current flows, and film uniformity, a final configuration consisting of 5% nanopatterned Nafion cured at 65°C was chosen. Multielectrode arrays (MEAs) were then covered with optimized Nafion nanopatterns and used for electrophysiological analysis of two types of induced pluripotent stem cell-derived cardiomyocytes (iPSCs-CMs). These data highlight the suitability of nanopatterned Nafion, combined with MEAs, for enhancing the cellular environment of iPSC-CMs for use in electrophysiological analysis in vitro.

Decreased genetic diversity in Kiso horses revealed through annual microsatellite genotyping.

The Kiso horse is native to Japan and is on the verge of extinction. Here, we used microsatellites to characterize changes in their genetic diversity over time. We divided a population of Kiso horses that genotyped during 2007-2017 into three groups based on birth year: Group 1, 1980-1998 (70 horses); Group 2, 1999-2007 (61 horses); and Group 3, 2008-2017 (42 horses). We genotyped 31 microsatellites to calculate average number of alleles, observed heterozygosity, and expected heterozygosity. All indicators decreased across age groups. The results indicate that Kiso horses have been experiencing a drop in genetic diversity, and the population is expected to experience further decline unless appropriate measures are implemented.

Genetic Association between Swine Leukocyte Antigen Class II Haplotypes and Reproduction Traits in Microminipigs.

The effects of swine leukocyte antigen (SLA) molecules on numerous production and reproduction performance traits have been mainly reported as associations with specific SLA haplotypes that were assigned using serological typing methods. In this study, we intended to clarify the association between SLA class II genes and reproductive traits in a highly inbred population of 187 Microminipigs (MMP), that have eight different types of SLA class II haplotypes. In doing so, we compared the reproductive performances, such as fertility index, gestation period, litter size, and number of stillbirth among SLA class II low resolution haplotypes (Lrs) that were assigned by a polymerase chain reaction-sequence specific primers (PCR-SSP) typing method. Only low resolution haplotypes were used in this study because the eight SLA class II high-resolution haplotypes had been assigned to the 14 parents or the progenitors of the highly inbred MMP herd in a previous publication. The fertility index of dams with Lr-0.13 was significantly lower than that of dams with Lr-0.16, Lr-0.17, Lr-0.18, or Lr-0.37. Dams with Lr-0.23 had significantly smaller litter size at birth than those with Lr-0.17, Lr-0.18, or Lr-0.37. Furthermore, litter size at weaning of dams with Lr-0.23 was also significantly smaller than those dams with Lr-0.16, Lr-0.17, Lr-0.18, or Lr-0.37. The small litter size of dams with Lr-0.23 correlated with the smaller body sizes of these MMPs. These results suggest that SLA class II haplotypes are useful differential genetic markers for further haplotypic and epistatic studies of reproductive traits, selective breeding programs, and improvements in the production and reproduction performances of MMPs.

Influence of swine leukocyte antigen haplotype on serum antibody titers against swine erysipelas vaccine and reproductive and meat production traits of SLA-defined selectively bred Duroc pigs.

We investigated possible associations of SLA class II haplotypes with serum antibody titers against a swine erysipelas vaccine, reproductive and meat production traits using a population of selective breeding Duroc pigs. In the selective breeding Duroc pigs, four SLA class II-DRB1 and -DQB1 alleles were assigned by using PCR-sequence specific primer technique. Low-resolution haplotype (Lr)-0.30 and/or Lr-0.13 were deduced from the SLA class II alleles in the population of SLA-defined Duroc pigs. SLA-homozygous piglets with the Lr-0.30 haplotype had relatively lower serum antibody titers against the vaccine compared to those with Lr-0.13. In contrast, there were no statistically significant differences in reproductive performance between the SLA-defined pigs with two SLA class II haplotypes. Weaning and rearing rates until the body weight of 105 kg was reached in homozygous piglets with Lr-0.30 were significantly lower than those in homozygous piglets with Lr-0.13. The SLA-defined pigs had lower birth and weaning weights, body weights at 60 days of age, and daily weight gains than non-selective breeding Duroc pigs. Furthermore, the SLA-defined pigs had slightly lower back fat thickness compared to the non-selective breeding pigs. The rib eye areas of homozygous or heterozygous pigs with Lr-0.13 were larger than those of homozygous pigs with Lr-0.30 and non-selective breeding pigs. These data suggested that SLA haplotypes had the potential as useful genetic markers for selective breeding in the population of SLA-defined Duroc pigs.

Genetic association of swine leukocyte antigen class II haplotypes and body weight in Microminipigs.

OBJECTIVE: Microminipigs are a novel animal model with extensive applications in laboratory studies owing, in part, to their extremely small body sizes. In this study, the relationship between swine leukocyte antigen (SLA) class II haplotype and body weight was evaluated in the Microminipig population. METHODS: A total of 1,900 haplotypes, covering SLA class II haplotypes Lr-0.7, Lr-0.23, Lr-0.17, Lr-0.37, Lr-0.16, Lr-0.11, Lr-0.13, and Lr-0.18, were analyzed in 950 piglets. Birth weights and weights on postnatal day 50 were examined in piglets with eight different SLA class II haplotypes. RESULTS: The mean birth weight of piglets with the Lr-0.23 haplotype (0.415 kg, n = 702) was significantly lower than that of piglets with Lr-0.17 (0.445 kg, n = 328) and Lr-0.37 (0.438 kg, n = 383) haplotypes. At postnatal day 50, the mean body weight of piglets with the Lr-0.23 haplotype (3.14 kg) was significantly lower than that of piglets with the Lr-0.13 haplotype (3.46 kg, p<0.01). There were no significant differences in daily gains (DGs) among the eight haplotypes. However, piglets with the Lr-0.11 and -0.18 haplotype combination or any heterozygous haplotype combinations containing Lr-0.23 had significantly lower DGs than those of piglets with the Lr-0.18, 0.37 haplotype combination. CONCLUSION: Piglets with the Lr-0.23 haplotype had relatively low body weights at birth and on postnatal day 50 and slightly lower DGs than those of piglets with other haplotypes. Therefore, the Lr-0.23 SLA class II haplotype may be a suitable marker for the selective breeding of Microminipigs with small body sizes.

Distribution of the CD4 Alleles in Sus scrofa Demonstrates the Genetic Profiles of Western Breeds and Miniature Pigs.

Widely used antipig CD4 monoclonal antibodies (mAbs) fail to recognize CD4 alleles characteristic of miniature pig lines such as the National Institutes of Health (NIH) miniature pigs and microminipigs. We surveyed polymorphisms in the coding sequence of the porcine CD4 gene among Western and Oriental pig breeds and Japanese wild boars and investigated their distribution. Of the 13 alleles that we identified among the 47 animals, 2 in group I and 3 in group II were found exclusively in Western breed pigs. Group IV alleles, which included mAb-nonbinding alleles, were found frequently in Oriental breed pigs, suggesting that the mAb-nonbinding allele arose from the gene pool of Oriental pigs. Group IV alleles were also found in Duroc and Large White pigs, suggesting genetic inflow from Oriental pig breeds into Western breeds. Comparison of the CD4 sequences of species in Cetartiodactyla suggested that the group IV alleles in Sus scrofa occurred before the divergence of this species from the other artiodactyls. The different antibody specificities of the various CD4 alleles may facilitate the discrimination of T-cell populations in transplantation studies using miniature pigs. The significance of the preservation of CD4 polymorphisms to immune function in pigs warrants further investigation.

Identification and characterization of two CD4 alleles in Microminipigs.

BACKGROUND: We previously identified two phenotypes of CD4+ cells with and without reactions to anti-pig CD4 monoclonal antibodies by flow cytometry in a herd of Microminipigs. In this study, we analyzed the coding sequences of CD4 and certified the expression of CD4 molecules in order to identify the genetic sequence variants responsible for the positive and negative PBMCs reactivity to anti-pig CD4 monoclonal antibodies. RESULTS: We identified two CD4 alleles, CD4.A and CD4.B, corresponding to antibody positive and negative, respectively, by nucleotide sequencing of PCR products using CD4 specific primer pairs. In comparison with the swine CD4 amino-acid sequence [GenBank: NP_001001908], CD4.A had seven amino-acid substitutions and CD4.B had 15 amino-acid substitutions. The amino-acid sequences within domain 1 of CD4.B were identical to the swine CD4.2 [GenBank: CAA46584] sequence that had been reported previously to be a modified CD4 molecule that had lost reactivity with an anti-pig CD4 antibody in NIH miniature pigs. Homozygous and heterozygous CD4.A and CD4.B alleles in the Microminipigs herd were characterised by using the RFLP technique with the restriction endonuclease, BseRI. The anti-pig CD4 antibody recognized pig PBMCs with CD4.AA and CD4.AB, but did not recognized those with CD4.BB. We transfected HeLa cells with the FLAG-tagged CD4.A or CD4.B vectors, and certified that transfected HeLa cells expressed FLAG in both vectors. The failure of cells to react with anti-CD4 antibodies in CD4.B pigs was associated to ten amino-acid substitutions in domain 1 and/or one amino-acid substitution in joining region 3 of CD4.B. We also found exon 8 was defective in some CD4.A and CD4.B resulting in the loss of the transmembrane domain, which implies that these CD4 proteins are secreted from helper T cells into the circulation. CONCLUSIONS: We identified that amino-acids substitutions of domain 1 in CD4.B gave rise to the failure of some CD4 expressing cells to react with particular anti-pig CD4 monoclonal antibodies. In addition, we developed a PCR-RFLP method that enabled us to simply identify the CD4 sequence variant and the positive and negative PBMCs reactivity to our anti-pig CD4 monoclonal antibodies without the need to use flow cytometric analysis.

Production of a Locus- and Allele-Specific Monoclonal Antibody for the Characterization of SLA-1*0401 mRNA and Protein Expression Levels in MHC-Defined Microminipigs.

The class I major histocompatibility complex (MHC) presents self-developed peptides to specific T cells to induce cytotoxity against infection. The MHC proteins are encoded by multiple loci that express numerous alleles to preserve the variability of the antigen-presenting ability in each species. The mechanism regulating MHC mRNA and protein expression at each locus is difficult to analyze because of the structural and sequence similarities between alleles. In this study, we examined the correlation between the mRNA and surface protein expression of swine leukocyte antigen (SLA)-1*0401 after the stimulation of peripheral blood mononuclear cells (PBMCs) by Staphylococcus aureus superantigen toxic shock syndrome toxin-1 (TSST-1). We prepared a monoclonal antibody (mAb) against a domain composed of Y102, L103 and L109 in the α2 domain. The Hp-16.0 haplotype swine possess only SLA-1*0401, which has the mAb epitope, while other haplotypes possess 0 to 3 SLA classical class I loci with the mAb epitopes. When PBMCs from SLA-1*0401 homozygous pigs were stimulated, the SLA-1*0401 mRNA expression level increased until 24 hrs and decreased at 48 hrs. The kinetics of the interferon regulatory transcription factor-1 (IRF-1) mRNA level were similar to those of the SLA-1*0401 mRNA. However, the surface protein expression level continued to increase until 72 hrs. Similar results were observed in the Hp-10.0 pigs with three mAb epitopes. These results suggest that TSST-1 stimulation induced both mRNA and surface protein expression of class I SLA in the swine PBMCs differentially and that the surface protein level was sustained independently of mRNA regulation.

Effects of D-allulose on glucose metabolism after the administration of sugar or food in healthy dogs.

D-allulose is a C-3 epimer of D-fructose and has recently been investigated for its hypoglycemic effects. In the present study, the effects of D-allulose on glucose metabolism were evaluated in healthy dogs administrated sugar or food. The oral administrations of D-allulose decreased plasma glucose concentrations after oral glucose or maltose administration, with a diminished plasma insulin rise. The glucose suppressive effect of D-allulose was also observed after intravenous glucose administrations without increase in plasma insulin concentration. In contrast, D-allulose showed no effect on plasma glucose and insulin concentrations after feeding. The present results suggest that D-allulose administration may be beneficial in dogs with impaired glucose tolerance. Further studies investigating the therapeutic efficacy of D-allulose in diabetic dogs are required.

Single oral dose safety of D-allulose in dogs.

Healthy dogs were administered acute oral doses of D-allulose (also called D-psicose) to evaluate its toxicity. Six dogs received oral doses of either a placebo or D-allulose solution (1 and 4 g/kg) on three different study days. One dog experienced vomiting, and five dogs showed transient diarrhea when 4 g/kg of D-allulose was administered. All dogs were active and had a good appetite throughout the study period. Blood glucose concentration slightly decreased without a rise in plasma insulin concentration 2 hr after D-allulose administration. Plasma alkaline phosphatase activities showed a mild increase between 12 and 48 hr after D-allulose administration. These data suggested that a single oral dose of D-allulose does not show severe toxicity in dogs.

Molecular cloning of feline resistin and the expression of resistin, leptin and adiponectin in the adipose tissue of normal and obese cats.

Resistin, one of the adipokines that has a cycteine-rich C-terminus, is considered to relate to the development of insulin resistance in rats. However, in cats, there is little knowledge regarding resistin. In this study, we cloned the feline resistin cDNA from adipose tissue by RT-PCR. The feline resistin clone contained an entire open reading frame encoding 107 amino acids that had 72.8%, 75.4%, 50.9% and 51.8% homology with bovine, human, mouse and rat homologues, respectively. In both subcutaneous and visceral adipose tissues, the transcription levels of feline resistin mRNA were significantly higher in obese cats than normal cats, and those of feline adiponectin mRNA were significantly lower in obese cats than normal cats. However, there was no difference in the expression of feline leptin between normal and obese cats. On the other hand, in both normal and obese cats, there were no significant differences in resistin, leptin and adiponectin mRNA levels between subcutaneous and visceral adipose tissues. In cats, the altered expression of resistin and adiponectin mRNA with obesity may contribute to the pathogenesis of insulin resistance and subsequent diabetes mellitus. In addition to feline adiponectin, the feline resistin cDNA clone obtained in this study will be useful for further investigation of the pathogenesis of obesity in cats.

Magnetic Resonance Imaging of Ovarian Activity in Microminipigs Showing Normal Estrous Cycles.

We investigated whether magnetic resonance imaging (MRI) might be applicable to evaluation of the ovarian activity of microminipigs. Firstly, using three mature microminipigs, we confirmed ovarian position and morphology by laparotomy or laparoscopy, and then acquired MRI images in various patterns to determine the most suitable condition for the acquisition. Next, using four microminipigs, we performed daily MRI, starting 10 days after ovulation and ending 10 days after the subsequent ovulation, as the starting day of standing estrus was taken as day 0. While the ovarian structure could not be discriminated on T1-weighted imaging, it was possible to confirm the follicles during estrus as hyperintense regions on T2-weighted imaging. With chronological MRI, 3-5 follicles were visible on T2-weighted imaging during the interval from day -2 to day 1, and their size immediately prior to ovulation was 3-5 mm. However, confirmation of the presence of small follicles and the corpus luteum was difficult.

Identification of a CD4 variant in Microminipigs not detectable with available anti-CD4 monoclonal antibodies.

The Microminipig is an extra-small sized novel miniature pig developed in Japan. In the process of peripheral blood mononuclear cells analysis by flow cytometry, CD4+ cells could not be detected in some pigs with an anti-pig CD4 antibody (clone 74-12-4), or in some pigs with two other antibodies from different clones (MIL17 and PT90A). In a herd of 178 Microminipigs, 87 pigs (48.9%) were reactive with the anti-CD4 antibody (designated as CD4.A), and 91 pigs (51.1%) were non-reactive (designated as CD4.B). The CD4 types of piglets delivered from parents with CD4.A were CD4.A or CD4.B, and piglets delivered from parents with CD4.B were only CD4.B. This implies that the CD4.A pigs were homozygous for CD4.A or heterozygous for CD4.A and CD4.B, and the CD4.B pigs were homozygous for CD4.B. The CD4.B trait might be recessive. Significant differences could not be found in the percentage of CD3+ and CD8+ cells in whole lymphocytes between CD4.A and CD4.B animals. In the profile of CD4.B pigs, CD4+CD8+ T cells appeared to be detected in the CD4-CD8+ T cell region because the CD8 dull T cell population was observed. Thus, we considered that the CD4 molecules may be expressed on helper T cells, but the CD4 expressing cells could not be detected with the three anti-pig CD4 antibodies. Clinical abnormalities have not been observed in CD4.B pigs. Significant differences were not observed in immunoglobulin concentrations between CD4.A and CD4.B, though lower tendency was observed in plasma IgM concentrations from CD4.B pigs >36-months-old. These results imply that the CD4.B does not affect basic humoral immunity in vivo.

Ligand-binding characteristics of feline insulin-binding immunoglobulin G.

Polyclonal immunoglobulin (Ig) G autoantibodies against insulin have been identified in sera of healthy cats. We purified and fractionated insulin-binding IgGs from cat sera by affinity chromatography and analyzed affinity of insulin-binding IgGs for insulin and their epitopes. Following the passing of fraction A, which did not bind to insulin, insulin-binding IgGs were eluted into two fractions, B and C, by affinity chromatography using a column fixed with bovine insulin. Dissociation constant (KD) values between insulin-binding IgGs and insulin, determined by surface plasmon resonance analysis (Biacore™system), were 1.64e(-4) M for fraction B (low affinity IgGs) and 2e(-5) M for fraction C (high affinity IgGs). Epitope analysis was conducted using 16 peptide fragments synthesized in concord with the amino acid sequence of feline insulin by an enzyme-linked immunosorbent assay. Fractions B and C showed higher absorbance (affinity) of the peptide fragment of 10 amino acid residues at the carboxyl-terminal of the B chain (peptide No. 19), followed by peptide fragments of 6 to 15 amino acid residues of the B chain (peptide No. 8). Fraction C showed a higher absorbance to 7 to 16 amino acid residues of the B chain (peptide No. 5) compared with the absorbance of fraction B. Polyclonal insulin-binding IgGs may form a macromolecule complex with insulin through the multiple affinity sites of IgG molecules. Feline insulin-binding IgGs are multifocal and may be composed of multiple IgG components and insulin.

Body and major organ sizes of young mature microminipigs determined by computed tomography.

To understand the anatomical characteristics of microminipigs, one of the smallest miniature pigs, as a large animal model, we measured the body and organ sizes of four-, five-, six-, and seven-month-old microminipigs (n = 4, females) using computed tomography. In addition, the results were compared with those of young mature beagles (10 months old, two males and three females), which have been widely used as a large animal model. The microminipigs at 4-6 months of age were much smaller than the beagles. However, when the microminipigs reached seven months of age, their overall size was similar to that of the beagles. The thoracic cavity volume of the seven-month-old microminipigs was less than half that of the beagles, and the cavity was largely filled by the heart. The liver size of the seven-month-old microminipigs was approximately half of that of the beagles. Moreover, the spleen of the seven-month-old microminipigs was different in morphology, but not different in size from that of the beagles. In addition, although their volumes were the same, the kidneys of the seven-month-old microminipigs, unlike those of the beagles, were flattened in shape. Collectively, the major abdominal organs of the seven-month-old microminipigs were either the same size or smaller than those of the beagles, but the abdominal cavity volume of the seven-month-old microminipigs was larger than that of the beagles. Thus, the abdominal cavity of microminipigs is assumed to be filled with the gastrointestinal tract. The anatomical characteristics of the young mature microminipigs revealed in our study suggest that microminipigs could have great potential as a large animal model for biomedical research.