According to current concepts, hypertension and hyperlipidemia cause vascular damage that leads to a hypercoagulative state. In this study, we investigated whether spontaneously hypertensive and hyperlipidemic rats (SHHR) can be a useful experimental model for complications in combined hypertension and hyperlipidemia, by comparing coagulative and fibrinolytic activities in SHHR with those in spontaneously hypertensive rats (SHR) and spontaneously hyperlipidemic rats (HLR). We measured coagulation and fibrinolysis markers in plasma and levels of fibrinogen and prothrombin mRNA in livers of eight-month-old male Wistar Kyoto rats (WKY), Sprague-Dawley rats (SD), SHR, HLR and SHHR. The plasma levels of fibrinogen in SHR, HLR and SHHR were significantly higher than those in WKY and SD, and were highest in SHHR. Higher plasma levels of antithrombin III and plasminogen were detected in increasing order in SHR, HLR and SHHR as compared to those in WKY and SD. Hepatic mRNA expressions of fibrinogen chains and prothrombin were enhanced in SHR, HLR and SHHR, resulting in increased plasma fibrinogen levels in SHHR. These results suggest that hypertension and hyperlipidemia can each cause hypercoagulation, with hyperlipidemia being a stronger factor than hypertension. Since a greater hypercoagulative state is a complication of combined hypertension and hyperlipidemia, the SHHR model is a good system for studying the early stage of atherosclerosis ensuing from hyperfibrinogenemia.

View full abstract

To develop a minipig model of type 2 diabetes that simulates the common manifestations of the metabolic abnormalities and resembles the kidney pathology of type 2 diabetes in the human population, male Chinese Bama minipigs were divided into 2 groups (5 in each) and fed with a control diet (CD) or high-fat/ high-sucrose/ high-cholesterol diet (HFSCD) for 5 months. The biochemical parameters of blood and urine, and the oral glucose tolerance test were monitored after the feeding program. The insulin resistance was estimated by the HOMA-IR index and the glucose elimination constant (K_G), and beta-cell function by the HOMA-beta index and the acute insulin response (AIR). Glomerulosclerosis index (GSI) was semi-quantitated by the degree of glomerular lesions in kidney sections stained with Masson trichrome. Extracellular matrix deposition in the kidney was examined by the protein expression of type IV collagen, connective tissue growth factor (CTGF) and matrix metalloproteinases 2 (MMP-2) using immunohistochemistry. Feeding HFSCD to minipigs markedly caused hyperglycaemia, hyperinsulinaemia and dyslipidaemia. HOMA-IR was significantly increased while HOMA-beta, AIR and K_G were obviously decreased in the HFSCD group compared with control group. Microalbuminuria, glucosuria and moderate glomerulosclerosis were exhibited in HFSCD-fed minipigs. The expression of type IV collagen and CTGF was elevated whereas that of MMP-2 was reduced in the kidneys of HFSCD group compared with the CD group. We concluded that feeding HFSCD to Chinese Bama minipigs for 5 months can induce humanoid type 2 diabetes and early-stage diabetic nephropathy, and accelerate extracellular matrix deposition and glomerulosclerosis.

View full abstract

In this study, we focused on age-dependent changes in intracellular iron deposition in the gerbil hippocampus. At 1 month of age (PM 1), iron reactivity was weak in the gerbil hippocampus. At this time, cells in the polymorphic layer of the dentate gyrus showed weak iron reactivity. At PM 3, iron reactivity in cells had not changed significantly. Thereafter, iron reactivity in the CA1-3 regions and in the dentate gyrus increased with time until PM 18. At PM 24, iron reactivity in all the subfields was similar to that at PM 18. In animals aged PM 18-24, iron positive cells had various shapes, and had processes which contained iron. These results suggest that the increase of iron deposition may be associated with normal aging and that the iron deposition in the aged hippocampus is different according to hippocampal subfields.

View full abstract

The rabbit is considered to be a valuable laboratory animal. We compared 2% acetamide and glycerol as cryoprotectants in egg-yolk diluent for ejaculated Japanese white rabbit spermatozoa to improve sperm cryopreservation methods. Fertility through artificial insemination, forward progressive motility and plasma membrane integrity of the post-thaw spermatozoa were examined. The rates of forward progressive motility and plasma membrane integrity of the spermatozoa frozen with acetamide (27.1 ± 8.3% and 24.5 ± 6.5%) were significantly (P<0.05) higher than those of the spermatozoa frozen with glycerol (16.3 ± 10.9% and 14.3 ± 7.6%). Though there was no significant difference in the kindling rates, the litter size of females inseminated with spermatozoa frozen with acetamide (6.0 ± 1.1) were significantly (P<0.05) higher than those of spermatozoa frozen with glycerol (3.0 ± 0.4). The results indicate that 2% acetamide has a higher cryoprotective effect than 2% glycerol for sperm cryopreservation in the Japanese white rabbit.

View full abstract

In this study, it was aimed to demonstrate the possible oxidative stress caused by exposure of xylene and formaldehyde (HCHO) on liver tissue, and on body and liver weights in adult as well as developing rats. The rats (96 female Sprague-Dawley) were randomly divided into four groups: embryonic day 1 (Group 1), 1-day-old infantile rats (Group 2), 4- week-old rats (Group 3) and adult rats (Group 4). The animals were exposed to gases of technical xylene (300 ppm), HCHO (6 ppm) or technical xylene + HCHO (150 ppm + 3 ppm), 8 hours per day for 6 weeks. Superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) and malondialdehyde (MDA) levels were evaluated. In addition, body and liver weights were determinated. Compared to the control animals, body and liver weights were decreased in the embryonic day 1 group (P<0.001, P<0.01, respectively) and the 1-day-old infantile group (P<0.001). Liver weight was increased in the 4-week-old group (P<0.01). SOD activities were decreased in the 4-week-old rats exposed to HCHO (P<0.01). CAT activities increased in the embryonic day 1 group (P<0.05). GSH levels were decreased in the 1-day-old infantile group (P<0.01), and MDA levels was increased in the embryonic day 1 group (P<0.05) as compared with the respective control groups. As to GSH and MDA levels in adult and 4-week-old animals, no statistically significant differences were observed (P>0.05). The present study indicates that exposures to xylene, HCHO and a mixture of them are toxic to liver tissue, and developing female rats are especially more adversely affected. Furthermore, the results of this study show that adult female rats could better tolerate the adverse effects of these toxic gases.

View full abstract

This study was undertaken to investigate whether the concentration of carbonic anhydorase isoenzyme I (CA-I) in canine feces and urine is useful as a temporary marker of occult blood. Concentrations of CA-I were measured by enzyme-linked immunosorbent assay (ELISA). Fecal CA-I concentrations in 113 healthy beagle dogs (50 male and 63 female) of various ages ranged from 4.3 to 16.7 ng/g feces (mean; 7.0 ± 2.9 ng/g feces). One milliliter of blood from 3 healthy beagle dogs was found to contain 1,047, 1,062 and 1,150 μg CA-I. The fecal CA-I concentrations of dogs receiving intragastric infusions of autologous blood (10 ml) were very low. However, the fecal CA-I concentrations of dogs receiving infusion of autologous blood (5 ml) into the ascending colon were very high. Detection of fecal CA-I would be useful for identifying dogs with hemorrhaging of the large intestine. Of 55 urinary samples collected from healthy beagle dogs by catheter, chemical tests for occult blood were negative in 44, but CA-I concentrations ranged from 1.8 to 12.6 ng/ml (mean; 6.9 ± 5.4 ng/ml) by ELISA. The CA-I concentrations of the other 11 samples, which tested positive for occult blood on chemical testing, ranged from 41.2 to 525.0 ng/ml by ELISA. Although CA-I is not a specific marker of erythrocytes, CA-I may be used to detect occult blood in canine feces and urine until a specific immunological test kit using antibody for Hb is developed.

View full abstract

Ten microsatellite DNA loci developed for the white-toothed shrew (Crocidura russula) were tested for PCR amplification and for utility in linkage studies in the house musk shrew, Suncus murinus. Four primer pairs successfully yielded PCR amplicons and showed polymorphism between two mutant strains, BAN-kc,oeb and WZ. Cloning and sequencing of the PCR amplicons of all the four loci confirmed the presence of microsatellite sequences. Alleles segregating in an F₂ resource population constructed from the two strains ranged between two and five. Linkage analysis of the four loci together with 18 other polymorphic markers and three mutant loci resulted in five linkage groups containing three newly mapped microsatellite loci. This study reports the first microsatellite markers being registered in this species.

View full abstract

The correlation among clinicopathological parameters of myocardial damage was investigated in rats administered a single subcutaneous dose of isoproterenol at 0 (saline), 0.04, 0.4 and 4 mg/kg. Total lactate dehydrogenase (LDH), creatine kinase (CK), and their isoenzymes (LDH-1, LDH-2 and CK-MB), as well as troponin I and tropinin T, were measured 4 h after the administration of the drug. Troponin I was determined by a chemiluminescence method using Bayer Centaur and DPC Immulyze, as well as by ELISA. Troponin T was assayed semi-quantitatively using Trop T Sensitive. A high correlation was found among LDH isoenzymes, troponin I (Centaur) and troponin T. The present result provides a baseline for interpreting changes in the different parameters of myocardial damage assayed by different methods in toxicity studies.

View full abstract

A new method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was developed for genetic typing of a point mutation of the Bruton's tyrosine kinase (Btk) gene in CBA/N mice bearing an X-linked recessive immunodeficiency (xid). Since restriction site useful for RFLP analysis does not exist in the spontaneous mutant Btk^xid locus, an artificial restriction site was introduced by PCR amplification with a modified primer. The five genotypes of the Btk locus (Btk^xid/ Btk^xid, Btk^xid /Btk⁺ and Btk⁺/Btk⁺ females and Btk^xid/Btk^null and Btk⁺/Btk^null males) could be distinguished by three patterns clearly and easily. This PCR-RFLP analytic method will be useful as a tool in the production of congenic mice and mice with multiple immunodeficient genes.

View full abstract

There are studies of the microbial flora of the normal canine ear canal, but it is difficult to compare their results because the parts of the ear examined are not described, and various breeds of dogs were used. Therefore, we used only beagles to study the normal microbial flora in three parts of the ear: the pinna, the anthelix, and the vertical ear canal. The rates of bacterial isolation from the three parts were 91.8%, 70.5% and 48.8%, respectively. The corresponding rates of isolating yeasts was 48.8%, 81.4%, and 83.7%, respectively. These results show that the physiologic factors of the three parts of the ear from which the samples were obtained must be radically different.

View full abstract