This study was performed to elucidate catecholamine release in the pulmonary circulation of isolated lungs due to the sympathetic nerve stimulation and to assess the experimental conditions which can modify the release, i.e., stimulus intensity, ventilation state of the lung and flow rate of perfusion. In artificially ventilated lungs, electrical stimulation of stellate ganglions evoked large noradrenaline efflux from the lung, but adrenaline efflux was below the detection limit, and dopamine was not detected in any case. In the unventilated preparations, the lung parenchyma were not bleached and the arterial pressure was significantly higher than in ventilated preparations. Noradrenaline efflux from the unventilated group was significantly lower than that from the ventilated preparations. The effect of the perfusion flow rate was investigated under pressure-operated ventilation. The pulmonary arterial pressure (Pa) was not varied at 5-10 ml min-1, but it was increased significantly at 20 ml min-1. Noradrenaline efflux was also increased significantly at 20 ml min-1. These results indicate that noradrenaline was the catecholamine exclusively released from pulmonary vasculature due to the sympathetic nerve stimulation, and that both ventilation and the perfusion flow rate could affect the release. The concomitant increase in arterial pressure indicates that noradrenaline efflux would be affected by the alteration in resistive small arteries. Circulatory change in these arteries is supposed to be one of the factors that modify noradrenaline release from the lungs. The analysis of noradrenaline should be a useful method to evaluate the sympathetic effect on the pulmonary vasculature.
We found a new coat color mutant in a population of Japanese wild mice (Mus musculus molossinus) and called the trait tawny. The tawny mutant is characterized by a light yellowish brown coat color. The tawny hair has a so-called agouti pattern, but the yellow band is greatly lengthened. There are no differences between the tawny and wild-type hairs in size and the number of melanosomes. Genetic analyses revealed that the tawny trait is an autosomal recessive and its gene is located in the distal region on Chromosome 8 between the microsatellite markers D8Mit87 and D8Mit122. An allelism test indicated the tawny mutant gene to be a new allele at the Mc1r locus and dominant to the recessive yellow (Mc1re). The proposed gene symbol for the tawny is Mc1rtaw.
Nine groups of ex-germfree (GF) rabbits were produced by inoculation of hysterectomy-derived GF rabbits with various combinations of cecal bacteria isolated from conventional (CV) rabbits in order to establish a barrier-sustained colony. Six strains of Bacteroides and two strains of Streptococcus isolated from CV rabbits (2 to 3 weeks old) were used for pretreatment. The mortality of ex-GF rabbits inoculated with the anaerobic growth (CF) on EG or SM10 plates inoculated with a 10-5 dilution of cecal contents was 71.4 to 94.4% when given without pretreatment. All ex-GF rabbits pretreated with Bacteroides alone survived, but the mortality of ex-GF rabbits inoculated with Bacteroides plus Streptococcus strains as pretreatment was 20 and 45.4%. The mortality of ex-GF rabbits inoculated with only Bacteroides was 43%. All ex-GF rabbits inoculated with Bacteroides plus anaerobic growth (CF), cecal suspension of ex-GF mice which had been inoculated with cecal suspensions of CV rabbits (MF) or chloroform-treated cecal suspension (CHF) survived, but CHF inoculated ex-GF rabbits were in an unhealthy condition with slight diarrhoea. These data indicate that inoculation with Bacteroides strains as pretreatment plus CF or MF was required to convert GF rabbits to the normal state.
The relationship between clinical parameters and pathological changes was investigated in an animal model of mononeuropathy, by behavioral, electrophysiological and histopathological methods. Mononeuropathy was induced in rats by loosely tying ligatures around the sciatic nerve. Eighty-four rats were used, and these were divided into fourteen groups to determine chronological changes in the withdrawal reflex latency, nerve conduction velocity and ultrastructure of the nerve from 1 to 84 days after nerve ligation surgery. Pathological changes around the ligated nerves were divisible in three phases: the first week was an inflammatory phase, when axonal degeneration, phagocyte infiltration and interstitial edematous changes were observed. The second and third weeks were a nerve-sprouting phase, when numerous axonal sprouts and remyelination were seen. The fourth to twelfth weeks were a recovery phase in which maturing myelination and interstitial fibrosis were characteristic. In the inflammatory phase, withdrawal reflex latencies were shortened, and sensory nerve conduction velocities (SCV) and motor nerve conduction velocities (MCV) gradually decreased. In the nerve-sprouting phase, the latency values remained low, and SCV and MCV were minimal. The parameters examined gradually returned to control levels during the recovery phase. In conclusion, these findings increase the knowledge of disease progression in mononeuropathy with hyperalgesia in human and animal models.
We raised an experimental rat implanted with a cecal fistula and investigated various characteristics of fistula-implanted rats. Male F344/N Slc rats at 14 weeks of age were divided into three groups, the fistula group (n=5) which consisted of fistula-implanted rats, the sham group (n=7) which consisted of sham-operated rats, and the control group (n=7) which were not subjected to any surgical procedure. Four weeks after the fistula implantion surgery, we compared the blood biochemical indices, the microflora composition and the short-chain fatty acids (SCFA) concentration in cecal contents of fistula-implanted rats with those of sham-operated and control rats. The blood albumin concentration of the fistula group was significantly lower than that of the sham group and the control group, and the hematocrit value of the fistula group was significantly lower than that of the control group, but there were no significant differences in the SCFA concentration and the microflora composition among these three groups. In conclusion, it was considered that the fistula-implanted rats are useful for taking cecal contents and determining the microflora composition and the metabolites concentration at any time, without disturbing the physiological functions of the intestinal tract.
In the present study we attempted to establish specific-pathogen-free (SPF) rabbit breeding colonies with two groups of limited-flora (LF) rabbits, both ex-germfree rabbits, and their offspring. Two groups of LF rabbits associated with cecal flora of conventional (CV) rabbits produced in a previous study [Exp. Animals, submitted], were transferred to individual barrier rooms and some of the LF rabbits were accomodated in isolators to maintain the basic flora for SPF rabbits. The composition of the cecal flora of LF rabbits was stable for a long period; bacteroides remained predominant and clostridia dominant. From the SPF rabbits, different types of bacteria, e.g., enterobacteriaceae and streptococci, which could not be isolated in the isolator were detected at a low population level at an early stage in the establishment of the SPF colonies, but the basic composition of the cecal flora was mainly bacteroidaceae and clostridia and did not change over a long period, and the floral composition became similar to that of CV rabbits. The fertility and weaning rates of the SPF rabbits were satisfactory for a SPF rabbit colony. In addition, these SPF colonies were free of more than one year rabbit-specific pathogens.
Leukocyte differential analysis was performed in various species, particularly laboratory animals, by the laser multi-angle polarized light scattering separation method. Venous blood specimens were drawn from the following subjects: healthy adult men and women ("humans"); cynomolgus monkeys ("monkeys"); common marmosets ("marmosets"); beagle dogs ("dogs"); miniature potbelly pigs ("swine"); Japanese white rabbits ("rabbits"); Hartley guinea pigs ("guinea pigs"); and Sprague-Dawley rats ("rats"). 90°/10° scatter plot: Basophils and mononuclear-polymorphonuclear cells were separated in all subjects, but individual 10° and 90° scatter plots overlapped in dogs and guinea pigs, respectively. 90° depolarized /90° scatter plot: Neutrophils and eosinophils were clearly separated in human, monkey, guinea pig, swine and rat subjects. The eosinophil cluster was not clearly plotted in marmoset, dog, or rabbit. 0°/10° scatter plot: Regarding this plot for monocytes and lymphocytes, cells were plotted in the following order in all subjects: lymphocytes < basophils ≤ monocytes in the 0° (size) scatter; and lymphocytes approximatery equal to monocytes ≤ basophils in the 10° (complexity) scatter. Compared to other species, the rat scatter showed a tendency to overlapping plots in both the 0° and 10° scatters in the monocyte and lymphocyte clusters. In both dog and guinea pig, the monocyte and neutrophil plots overlapped in the 0° and 10° scatters. Basobox: In the human and rabbit subjects, the basophil cluster was plotted within the established basobox, but no clear cell cluster was plotted in the other subjects. As a result of comparing the percentage values for leukocytes in various species obtained by using the CD3500 apparatus versus the corresponding values obtained manually, good correspondence was found in the monkey, and eosinophils in the marmoset were lower with CD3500 than manually. In the rabbit, the mean measured value for basophils matched in the manual and CD3500 findings. In the guinea pig, the CD3500 values were lower than the manual values for lymphocytes, but higher for monocytes and neutrophils. The above findings suggest that the laser multi-angle polarized light scattering separation method is indeed capable of analyzing leukocytes from various species based on cell size and cell complexity, i.e., the presence or absence of nuclei, granules and cell enclosures.
Diurnal changes in small intestinal intraepithelial lymphocytes (IELs) were examined in 8- to 10-week-old BALB/cA male mice. The ratio of T cell subsets expressing CD8αα homodimer/CD8 αβ heterodimer was found to be higher in the dark period than that in the light period. Increased expression of Thy-1.2 on γδ T cells was also observed in the light period. No significant changes were found in other subsets. This is the first report to document diurnal changes in the small intestinal IELs in mice.
Leishmania amazonensis is an intracellular protozoan parasite of macrophages. Cutaneous leishmaniasis in an immunocompetent host begins as papules or nodules followed by ulceration at the site of promastigote inoculation. In this study, the pathological changes of cutaneous leishmaniasis lesions in T cell deficient nude mice were examined. When infected with L. amazonensis promastigotes, nude mice developed non-ulcerative cutaneous nodules. By histological examination of cutaneous lesions, massive accumulation of vacuolated histiocytes containing amastigotes was observed in all the nude mice. Although infiltration of mononuclear and polymorphonuclear cells was seen in the lesions of immunocompetent mice, few such cells were observed in the lesions of nude mice. These results indicate the importance of T cells on the ulcer formation in cutaneous leishmaniasis.
We examined the changes in the appearance of osteoclasts in the femora of ovariectomized (OVX) or orchiectomized (ORX) op/op mice. Osteoclasts on the trabecular bone surface of the OVX or ORX op/op mice significantly increased in number seven or eight times in comparison with sham-operated op/op mice. Furthermore, TRAP-positive cells increased about four times in 100-week-old females and males, compared with sham-operated groups. These results have indicated that a sex hormone reduction due to OVX or ORX induces prominent recruitment of osteoclasts in op/op mice.
In rats, pseudopregnancy has been induced by mating with vasectomized males, by mechanical stimulation of the uterine cervix with a glass rod or vibrator, and by stimulation of the vagina with a tampon. On the other hand, no practical data are available in reports on the induction of pseudopregnancy in Mongolian gerbils. Pseudopregnancy of gerbils has been induced by mating with vasectomized males. But this method was uncertain because the incidence of pseudopregnancy was lower than that obtained in rats by other means. In the present study, two experiments were undertaken as follows. l) Copulatory behavior of gerbils was observed for one hour to determine the most effective stimulation interval. 2) From the results of Experiment 1, female gerbils in estrus were mechanically stimulated to test the effectiveness of inducing pseudopregnancy by vaginal stimulation at various time intervals. The results of these experiments indicated that, although the frequency of copulatory behavior varied among individuals, on average the most effective method for inducing pseudopregnancy was stimulation of 5 min duration and at 20 or 30 min intervals. Because the incidence of pseudopregnancy induced by such mechanical stimulation (83.3%) was higher than that induced by mating with vasectomized males (30.0%), this method might be useful in inducing pseudopregnancy in Mongolian gerbils.
We evaluated the ready-to-use liquid reagents for clinical chemistry (6 tests), to assess their suitability for use in the toxicology laboratory setting. Hitachi 736 automated analyzer was used for the analyses. The evaluation included the following studies: Precision, Linearity, Effects of interference substances such as hemolytic hemoglobin, bilirubin, turbidity to the analytical values and correlation to the solid reagents, which are prepared each time they are needed. The precision and linearity data were within the reagents' specifications. Results of comparison of the liquid reagents and the solid reagents in analyzing plasma samples of rats, dogs and monkeys were generally good except for a bias in results for GOT and GPT, regardless of the animal species tested. It is concluded that these types of liquid reagents can be used in clinical pathology examinations in animal studies.