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1. Inter-breed morphological comparisons were made among 11 breeds of Japanese native chickens (Gifujidori, Hinaidori, Shokoku, Totenko, Tomaru, Satsumadori, Shamo, Koshamo, Koeyoshi, Chabo and Nagoya), White Leghorn, broiler chickens (Chunky) and red junglefowl collected in the Philippines, based on results of direct measurements and analysis by computer vision techniques of the skull. 2. Analysis of direct measurements identified two groups of chicken: a small type that included the Chabo, Koshamo, red junglefowl, Gifujidori and Shokoku and a large type that included the remaining breeds studied. These groupings were made based on size determined both in the first (PC1) and second principal component (PC2). The greatest length of the cranium and condylobasal length greatly contributed to the morphological differences between these two groups. 3. Analysis by computer vision techniques, however, identified three groups: the Bantam group (which includes red junglefowl), Shokoku group and Shamo group. White Leghorn clustered within the Shokoku group while the broiler chicken belonged to the Shamo group. The region around the junction of the neural cranium and the visceral cranium contributed greatly to the morphological differences among breeds, both in the PC1 and PC2.

Polyethylene glycol (PEG) has been reported to inhibit the development of colonic lesions in carcinogen-treated rats when administered orally. However, the precise mechanism for the chemopreventive activity of PEG remains largely elusive. Based on a characteristic feature of PEG as a 'fusogen', we investigated its potential as a chemotherapeutic agent through the induction of multinucleated cell formation and apoptosis induction in PC-3 prostate cancer cells. When PC-3 cells were treated with 0.5 and 1.0% PEG 1000, multinucleated cells were induced at a frequency of 8.4 and 13%, respectively, 36 h after PEG treatment under high cell density (1 x 10(6) cells in 100 microL PEG solution) in vitro. Although abnormality of cell cycle progression was not evident in PEG-treated PC-3 cells, multinucleated cells substantially disappeared at around 38 h due to apoptosis. In contrast, no apparent growth suppression was observed when PC-3 cells were exposed to up to 1.0% PEG at a much lower cell density, namely under ordinary culture conditions. Furthermore, injection of 0.5% PEG solution in vivo into PC-3 xenografts implanted in BALB/c-nu/nu male mice significantly suppressed tumor growth compared to phosphate-buffered saline injection. Multinucleated TdT-mediated dUTP-biotin nick end-labeling (TUNEL)-positive cells were observed inside the PEG-injected tumors. PEG was here demonstrated to have anticell proliferation and antitumor effects via induction of apoptosis, possibly by cell fusion. PEG injection therapy could therefore be adopted as an alternative chemotherapeutic strategy for localized prostate cancers, including those that become refractory to androgen-deprivation therapy.

We examined unique erythrocyte pits of the peripheral blood and bone marrow in the lesser mouse deer, Tragulus javanicus, using scanning electron microscope (SEM) and transmission electron microscope (TEM). Under the SEM observation, the pit was observed as a hole on both mature erythrocytes of the peripheral blood and immature erythrocytes of the bone marrow. By the TEM, the mature erythrocytes had a vacuole, which showed complicated shape and occupied considerable space within the cytoplasm. The vacuole was communicated extracellularly by perforation, which corresponded to the hole on the cell surface. In the bone marrow, erythroblast and reticulocytes have a cytoplasmic vacuole. This abnormal feature of the erythrocytes is peculiar to the mouse deer, and not found in other tropical ruminants. Despite the disadvantage of volume loss from the small erythrocytes, the mouse deer were healthy and showed no signs of anaemia.

Summary The considerable phylogenetical differences between mouse deer and other ruminants have been established by means of DNA sequence analysis and anatomical observations. To clarify the physiological role of the uteroplacenta of the mouse deer, immunohistochemical observation was attempted by using GRP, which has been suggested as a novel regulatory peptide in the female reproductive tract, as an indicator to compare with other ruminants. Strong positive reactions for the GRP were detected in the uterine glands of the pregnant animals, but not in the non-pregnant ones. Although the placenta of the mouse deer is categorized as a diffuse placenta that is different from other ruminants’ polycotyledonary placenta, in terms of GRP immunoreactivity, the mouse deer placenta can be classified as a synepithecholial placenta like the other ruminants’. The secretion of GRP from the uterine glands is of some importance to the fetus in the mouse deer.

Summary The transition of fetal haematopoietic sites in mice was examined histologically from 12.5-day embryos (E12.5) until 10 days of age (D10), and the expression of the adhesive molecules VCAM-1 and fibronectin was examined immunohistologically. Erythropoiesis occurred in the liver (E12.5–18.5), spleen (E18.5–D4) and bone marrow (D6–10), in that sequence. Even at D10, some erythropoiesis occurred in the liver, and more so in the spleen, although the active haematopoietic site was the bone marrow. Similarly, granulopoiesis of neutrophils occurred in the liver, spleen and bone marrow in turn. Granulopoiesis still occurred in the spleen at D10, but no neutrophils were found in the liver after D4. VCAM-1 appeared in the liver, spleen and bone marrow in parallel with active erythropoiesis and granulopoiesis. The co-expression of VCAM-1 and fibronectin was recognized in the endothelial cells of the sinus at the onset of haematopoiesis. This study showed that haematopoiesis in the liver, spleen and bone marrow overlapped peri-natally, although it shifted sequentially. VCAM-1 appears to be closely associated with erythropoiesis and granulopoiesis, and the co-expression of VCAM-1 and fibronectin plays a role in inducing haematopoietic stem cells to move to the tissues.

Summary Fibre connections of the chick nucleus geniculatus lateralis ventralis (GLv) were investigated using the axonal tracing method with wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). After an injection of WGA-HRP into the GLv, many labelled neurons were observed in layer i of the stratum griseum et fibrosum superficiale (SGFS) in the ipsilateral tectum opticum (TO) and in the nucleus lentiformis mesencephali (LM). In the TO-GLv projection, cells of origin were located in the deeper part of layer i of the TO and were topographically distributed along the direction from the rostrodorsal part to the caudoventral part of the TO relating to a rostrocaudal axis of the GLv. In the LM-GLv connection, the dorsal and ventral parts of the LM connected reciprocally with the rostral and caudal halves of the GLv, respectively. In contrast, in the GLv efferent connection, labelled axon terminals spread widely in the ipsilateral area pretectalis without any clear topographical arrangement.

An experimental model to study interspecific pregnancy using voles, Microtus arvalis, and green fluorescent protein gene-induced transgenic mice is presented. Xenogeneic blastocysts from the vole were transferred into the uteri of pseudopregnant mice along with allogeneic blastocysts from green fluorescent protein gene-induced transgenic mice. The uteri containing xeno-allo combined transfers were examined from day 6 to 13 of gestation. Although the vole embryos implanted, the uteri containing vole embryos were smaller compared with those having allogeneic mouse embryos. On day 8, the uteri containing vole embryos hemorrhaged internally and no vole embryo was found in the pregnant uterus after day 11. Allogeneic mouse embryos developed normally despite the presence and abortion of the vole embryos. In uteri implanted with vole embryos, decidua were formed and numerous blood vessels were distributed around the embryo. Maternal blood cells infiltrated into the celomic cavity of the vole embryo through the discontinuous region of trophoblast. Periodic acid-Schiff-positive granulated metrial gland cells were remarkably increased in the decidual sites. These findings suggest that a disorder of embryo–maternal interaction might induce the appearance of numerous granulated metrial gland cells and rejection of the embryos.

Reproductive features of newly bred Russian voles (Microtus rossiaemeridionalis) as a laboratory animal were studied. This species is a copulatory ovulator, and most couples copulated 6 to 16 h after pairing. The gestation period varied from 18 to 22 days (mean +/- SD: 20.6 +/- 0.9, n = 72), and the average litter size was 4.6 +/- 1.9 (n = 125). Compared with the litter size at the first parturition (3.6 +/- 1.6, n = 72), the litter size in the subsequent parturitions increased to 5.9 +/- 1.4 (n = 53). The animals exhibited postpartum estrus, and repeated pregnancy accompanied with suckling pups and parturition continuously in the laboratory condition unlike other vole species. In view of their complex stomach and good proliferation, the Russian voles were evaluated as a good laboratory animal, especially as a model animal for ruminant studies.

Aniline hydrochloride (AH), a methemoglobin-formation stimulating substance, at a dosage level that does not induce apparent fetal death was injected subcutaneously into pregnant rats once a day on days 6–8, 9–11, 12–14 or 15–17 of gestation in order to assess its ability to stage-specifically produce cardiovascular malformations. In addition, AH at dosage levels of 195, 260, 325 and 395 rag/kg was injected into pregnant rats subcutaneously once a day on days 12–14 of gestation, and the dose-dependent induction of ventricular septal defect (VSD) in relation to maternal methemoglobinemia was studied. In the stage-specificity study, paleness, decreased body weight gain and elevated methemoglobin concentration were noted in the dams. Upon fetal examination, reduced body weight was noted in all AH-treated groups. AH induced cardiovascular malformations, mainly VSD, which was most frequently observed in the day 12–14 group and also observed in the day 15–17 group. Abnormal branching of subclavian, pulmonary and vertebral arteries were most frequently observed in the day 9–11 group. In the dose-dependency study, AH induced maternal methemoglobinemia, decreased fetal body weight and increased the incidence of VSD dose dependency. Additionally, administration of methylene blue, a methemoglobinemia-preventing substance, to the AH-treated dams ameliorated maternal methemoglobinemia and reduced the incidence of fetal VSD. From these results, it is considered that AH stage-specifically induces cardiovascular defects, mainly VSD, in rats and that VSD is induced not by a direct teratogenic effect of AH but by maternal hypoxia due to methemoglobinemia.

Aniline hydrochloride (AH), a methemoglobin formation-stimulating substance, at a dosage level of 520 mg/kg which does not induce apparent fetal death, was injected subcutaneously into pregnant rats once on day 14, 15 or 16 of gestation in order to assess the stage specificity of cleft palate induction. Also, doses of 260, 390, 520 and 650 mg/kg were administered to pregnant rats on day 15 of gestation, and the dose-response relationships with respect to fetal cleft palate and maternal methemo-globinemia induction were studied. In the stage-specificity study, paleness, decreased body weight gain and elevated methemoglobin concentration were noted in the dams treated with AH. Upon fetal examinations, although reduced body weight was noted in all AH-treated groups, cleft palate was observed only in fetuses from those dams treated on day 15 of gestation. In the dose-dependency study, AH induced maternal methemoglobinemia, decreased fetal body weight and increased the incidence of cleft palate dose dependently when administered at dosage levels of 260, 390, 520 and 650 mg/kg on day 15 of gestation. Additionally, administration of methylene blue, a methemoglobinemia-preventing substance, to the AH-treated dams ameliorated maternal methemoglobinemia and reduced the incidence of fetal cleft palate. In summation, it is considered that AH stage-specifically induces cleft palate in rats and that cleft palate is caused not by a direct teratogenic effect of AH but by maternal hypoxia due to methemoglobinemia.

The distribution in the chicken of motoneurons innervating the hyolingual muscles, i.e. the M. branchiomandibularis (BM), M. ceratoglossus (CG), M. interceratobranchialis (CB), M. serpihyoideus (PH), M. stylohyoideus (YH) and one of the mandibular muscles, M. depressor mandibulae (DM), was examined by retrograde transport of horseradish peroxidase conjugated with wheatgerm agglutinin. Labelled motoneurons are found in the three subnuclei of the facial (VII) nucleus, as well as hypoglossal (XII) nucleus. The distribution of motoneurons projecting to the DM are observed in the three subnuclei, those of the BM, PH and YH in the intermediate and ventral subnuclei and those of the CB and CG in the intermediate subnucleus. Motoneurons projecting to the PH, YH, CB and CG are also distributed in the XII nucleus. The ratio of labelled motoneurons of the VII to XII nuclei decreases the PH, YH, CB and CG in that order, and the ratio of labelled ones of the ventral to intermediate subnuclei decreases the BM, PH and YH in that order. The topographical and functional aspects of the subdivision of the motor nucleus are discussed.

Retinal projections in the Japanese field vole (Microtus montebelli) were determined by anterograde transport of horseradish peroxidase (HRP). Injection of HRP into the unilateral vitreous body demonstrated that the terminal labeling of the optic projections was seen bilaterally in the suprachiasmatic nucleus (SCH), the ventral (GLv) and dorsal (GLd) lateral geniculate nuclei, the intergeniculate leaflet (IGL), the medial pretectal nucleus (NTOM) of the pretectum (PT) and the superficial layer of the superior colliculus (CS), with contralateral predominance, and only contralaterally labeled terminals were found in the lateroposterior thalamic nucleus (LP), the lateral pretectal nucleus (NTOL) of the PT, the dorsal (DTN) and medial (MTN) terminal nuclei of the accessory optic system (AOS). The distribution area of the retinofugal terminals was divided into a three laminar arrangement in the GLd, i.e., layers 1 and 3 and layer 2, received the retinal input from contralateral and ipsilateral eye, respectively, as in arboreal squirrels. The contralateral CS received retinal fibers in the superficial layer, while ipsilateral optic fibers projected sparsely to the stratum opticum of the colliculi. Retinal connections to the DTN and MTN of the AOS were clearly discerned but no lateral terminal nucleus with retinal afferents was found. In addition, the AOS had no inferior fasciculus. These findings indicate that the vole has a contradictory features of a well- and a less-developed sense of vision. Namely, the image forming visual system such as the retino-GLd was as well-developed as in a squirrel, on the other hand, the non-image forming visual system such as the retino-AOS was less-developed as in an insectivore's brain.

Tetraploid mouse embryos usually cease to develop early after implantation, though they can develop to blastocysts. To characterize the failure of development in detail, tetraploid mouse embryos at the preimplantation period were examined as to both their morphology and number of cells. The tetraploid embryos were produced by 12 hr treatment with cytochalasin B (CB) at the 2-cell stage of backcross of (C57BL/6 x C3H/He) F1 x C3H/He. The tetraploid embryos in the preimplantation period exhibited compaction at 72 hr after hCG injection and blastocyst formation at 96 hr, as well as diploid embryos, but the number of cells composing the embryos was significantly smaller than that in the diploid embryos. At the term 60-96 hr after hCG injection, mean cell cycles were 14.03 hr in the tetraploid embryos, but 12.02 hr in the diploid. When tetraploid embryos were transferred into the oviducts of pseudopregnant recipients immediately after CB treatment, the number of cells in tetraploid blastocysts was increased compared with the embryos cultured in vitro, though the number did not reach that of diploid embryos. These results suggested that compaction and blastocyst formation in preimplantation development of tetraploid embryos depended on the time after hCG injection, irrespective of the number of cells or the length of the cell cycle. The lengthening of the cell cycle in tetraploid embryos may be one of the causes of failure in postimplantation development.

SMXA recombinant inbred (RI) strains of mice were produced by systematic inbreeding from the F2 generation of a cross between two progenitor inbred strains, A/J and SM/J, which differ considerably with respect to many characteristics, and consists of 28 inbred strains. In this study, we investigated the applicability of DNA fingerprinting with M13 phage DNA to the identification of these closely related strains. DNA fingerprints of the SMXA RI strains and their progenitors, SM/J and A/J, showed strain-specific patterns, with the same banding patterns within each strain. Linkage analysis by using strain distribution patterns of minisatellite loci with 108 genetic markers containing microsatellites, biochemical and immunological marker genes allowed 23 minisatellite loci to be assigned to 11 chromosomes. The results suggested that DNA fingerprinting with M13 phage DNA is applicable not only for strain identification but also for genetic monitoring of RI strains on almost all chromosomes.

Leydig cells of lesser mouse deer (Tragulus javanicus) testes were observed using light and transmission electron microscopies. Sexually mature lesser mouse deer were obtained in East Malaysia. The testes were perfused with 5% glutaraldehyde, postfixed with 1% OsO4, dehydrated in ethanol and embedded in Araldite. The semithin sections were cut, stained with toluidine blue and observed under light microscopy. The ultrathin sections were cut, stained with uranyl acetate and lead citrate, and examined using a JEM-1200 transmission electron microscope. As a result, two types of filament bundles were frequently recognized in Leydig cells, but not in other testicular cells. These bundles were clearly seen at even a light microscopic level. One type was bundles of actin filaments (approximately 5 nm in diameter). These structures were found not only in the cytoplasm but also in the nucleus. The other type was bundles of intermediate filaments (approximately 10 nm in diameter). These structures were found only in the cytoplasm. The existence of filament bundles has never been reported in the testicular cells of another mammalian species. Thus, while bundles of actin and intermediate filaments are specifically present in the Leydig cells of the lesser mouse deer, their functions are still unclear.

Identification of substrains or sublines of inbred mice and assessment of genetic relationships among them were performed on the basis of DNA fingerprinting using M13 phage DNA as a probe. We used eight C57BL/6 sublines (J parallel Jcl, J parallel Jms, J parallel Slc, J parallel Nrs, J parallel Yok, Jah, N parallel Crj, N parallel Jcl) and eleven C3H/He sublines, (J, J parallel Jcl, J parallel Yok, J parallel Nrs, J parallel Jms, N, N parallel Jcl, N parallel Crj, Slc, Jah, Nrs). Two kinds of restriction endonucleases (HinfI and PstI) were used. It was found that: 1) DNA fingerprint within each subline showed identical patterns. 2) Most sublines of C57BL/6 and C3H/He could be identified using DNA fingerprinting with HinfI except between N parallel Crj and Slc, and among J, J parallel Nrs and J parallel Yok in C3H/He. DNA fingerprints with PstI endonucleases showed low polymorphic banding patterns. 3) A dendrogram constructed from DNA fingerprint patterns reflected generally the genealogy of the sublines used. 4) DNA fingerprinting, therefore, seemed to be suitable for the genetic monitoring and assessment of genetic relationships among sublines of inbred mice having close relationships.

Protrusion of hyperplastic upper molar teeth (macrodonts) into the cranial cavity was observed in the Japanese field vole. Protrusions of the upper molars occurred on both sides, but were large on the left than on the right. The teeth invaded the cranial cavity and brain parenchyma. Large concavities on the ventral side of the brain were interposed between the lateral olfactory tract and the optic tract. Invation by one macrodont reached the basal nuclei, hypothalamic and thalamic nuclei. The brain was deformed bilaterally, and nearly the entire olfactory bulb, globus pallidus, internal capsule, and lateral preoptic nucleus, and a portion of the hypothalamus, thalamus and anterior commissure were absent on the left side.

Features of a long-haired mutant and inheritance of mutation were investigated in the golden hamster (Mesocricetus auratus). The hair of adult long-haired hamsters was longest at the rump and flanks (approximately 70 mm) and was also unusually long at the neck (45 to 50mm). The hair length of males was more striking than that of females. Mating experiments indicated that an autosomal recessive gene is responsible for the inheritance of long hair. An albino long-haired hamster strain was established by continuous full-sib mating from F2 hybrids, descendants of (acromelanic albino x agouti long-haired) F1 progeny, and genetic homogeneity was confirmed by DNA fingerprinting. The long-haired strain was characterised by the fact that males grew larger than females, in contrast to the other strains of hamsters.

Adrenocortical zonation in the laboratory Japanese field vole (Microtus montebelli) was investigated histologically with special attention to the sex and species specific differences. The whole cortex and zona reticularis showed clear sex differences. They were thicker in females than in males. In this respect the vole was similar to the mouse and rat, but different from the Syrian hamster and mastomys. Male cortices were characterized by thick z. fasciculata and meagre z. reticularis, while both zones were thick in females. The z. fasciculata in both sexes and z. reticularis in females seemed to be divided into two sublayers by the cellular arrangement. No distinctive additional zones were identified. The histological observations indicated that the Japanese field vole might have interesting endocrinological characteristics and serve for studying the mechanism of the zone formation in the mammalian adrenal cortex.

The distribution of lectin bindings in the testis of the smallest ruminant, lesser mouse deer (Tragulus javanicus), was studied using 12 biotinylated lectins specific for d-galactose (peanut agglutinin PNA, Ricinus communis agglutinin RCA I), N-acetyl-d-galactosamine (Dolichos biflorus agglutinin DBA, Vicia villosa agglutinin VVA, Soybean agglutinin SBA), N-acetyl-D-glucosamine and sialic acid (wheat germ agglutinin WGA, s-WGA), D-mannose and d-glucose (Lens culinaris agglutinin LCA, Pisum sativum agglutinin PSA, Concanavalin A Con A), L-fucose (Ulex europaeus agglutinin UEA I), and oligosaccharide (Phaseolus vulgaris agglutinin PHA-E) sugar residues. In Golgi-, cap-, and acrosome-phase spermatids, lectin-bindings were found in the acrosome (PNA, RCA I, VVA, SBA, WGA and s-WGA), and in the cytoplasm (PNA, RCA I, VVA, SBA, WGA, LCA, PSA, Con A and PHA-E). s-WGA binding was confined to the spermatid acrosome, but other lectins were also observed in spermatocytes. In spermatogonia, VVA, WGA, Con A, and PHA-E bindings were observed. Sertoli cells were intensely stained with DBA and Con A, and weakly with PHA-E. In interstitial Leydig cells, RCA I, DBA, VVA, Con A, PSA, LCA, WGA and PHA-E were positive. UEA I was negative in all cell types including spermatogenic cells. Unusual distribution of lectin-bindings noted in the testis of lesser mouse deer included the limited distribution of s-WGA only in the spermatid acrosome, the distribution of DBA in Sertoli cells, Leydig cells and lamina propria, and the absence of UEA I in all type cells. The present results were discussed in comparison with those of other animals and their possible functional implications.

The skin and lymphoid organs of Mexican hairless dogs and their hairless offspring were examined histologically. The hairless dogs lacked most hairs except for sparse hairs on the head, tail and feet. The skin of newborn pups consisted of a thick epidermis with epidermal ingrowths forming the rudiments of hair follicles. In older dogs more than 2 months of age, however, the epidermis was thin and the ingrowths were few. Neither hair follicles nor skin glands were present. The hairy skin of the head and tail had hair follicles with sebaceous glands. Regarding the lymphoid organs, the newborn pups possessed a thymus like haired pups. But in the older dogs more than 2 months of age, the thymus was atrophied and the lymphocyte population was too sparse to demarcate the cortex and the medulla. Lymphocyte accumulation in older dogs was also poor in the spleen and mesenteric lymph nodes. The present findings indicate that the hairlessness of the Mexican hairless dogs and their descendants is accompanied by early atrophy of the thymus after birth, and is followed by poor accumulation of lymphocytes in the thymus-dependent area of the spleen and the mesenteric lymph nodes. The defect of the thymus in the hairless dog seems to be different from that in athymic nude mice and rats. Further studies are needed to elucidate the immunological response and function in hairless dogs.

Inheritance of dilute coat color with pink eye in the Japanese field vole (Microtus montebelli) was investigated by mating of the dilute mutant with a normal agouti vole and a white vole. As the results, it was cleared that an autosomal recessive gene p is responsible for the pink-eyed dilution in M. montebelli.

We examined the expression of VCAM-1 and MAdCAM-1 after bone marrow transplantation (BMT). We also examined the influence of alpha(4)beta(7) integrin blockade on the homing of cells to the bone marrow and spleen. The expression of VCAM-1 and MAdCAM-1 by endothelial cells in the spleen and bone marrow was examined by immunoelectron microscopy using colloidal gold and was analyzed semiquantitatively. To examine the role of alpha(4)beta(7) integrin in donor cells, a homing assay was conducted following alpha(4)beta(7) integrin blockade in bone marrow-derived hematopoietic cells or spleen colony cells. Immediately after BMT, the expression of VCAM-1 and MAdCAM1 markedly decreased, but expression recovered significantly between 12 and 24 h after BMT. VCAM-1 recovered more acutely than MAdCAM-1 from 12 h onward. In the group transplanted with anti-alpha(4)beta(7) integrin antibody-treated bone marrow cells, the numbers of homing cells in the spleen and bone marrow were significantly decreased in an antibody dose-dependent manner. However, the number of homing cells was not different in either the spleen or bone marrow between anti-alpha(4)beta(7) integrin antibody treated and untreated spleen colony cells. It has been reported that alpha(4)beta(1) integrin and its receptor VCAM-1 play major roles in the homing of hematopoietic cells to bone marrow. Our study indicates the importance of MAdCAM-1 and its ligand, alpha(4)beta(7) integrin, in the homing of bone marrow-derived hematopoietic cells, but not spleen colony-derived cells, to both the spleen and bone marrow.

Short-term dextran sodium sulfate (DSS) treatment has been shown to notably accelerate colorectal tumor development in rats initiated with 1,2-dimethylhydrazine (DMH). In the present study, to clarify mechanisms underlying the DSS influence, time-course studies of histopathological and immunohistochemical characteristics and beta-catenin gene mutations in colorectal mucosa in early stages of this model were conducted. F344 males were given three subcutaneous injections of DMH (40 mg/kg body wt) within a week, followed by free access to drinking water containing 1% DSS for a week. At weeks 1, 4, 6 and 8 after the DSS treatment, rats were euthanized and colorectal samples were collected. At week 1, the colorectal mucosa demonstrated extensive erosion along with significant inflammatory cell infiltration and neighboring reactive hyperplasia. By week 4, the mucosal damage was repaired and regenerative mucosa, partly characterized by Paneth cell metaplasia and altered subcellular localization of beta-catenin, was apparent. Areas with Paneth cells/beta-catenin accumulation were significantly more likely to be accompanied by interstitial inflammation and 17 of 24 dysplastic foci were found in regenerative mucosa with Paneth cells. Furthermore, adenomas/carcinomas frequently featured various degrees of Paneth cell differentiation. Point mutations mainly in codons 34 and 41 of beta-catenin gene were detected in 6 of 27 samples of regenerative mucosa with Paneth cells and four of nine dysplastic foci/adenomas/carcinomas. These findings indicate that inflammation-associated regenerative mucosa with Paneth cell metaplasia and alteration in the APC/beta-catenin/Tcf signal transduction pathway are possibly involved in the acceleration of colorectal carcinogenesis in this DMH-DSS rat model.

The present study demonstrates the incidence of high lethality of F1 (Dh/+) male mice, the offspring of DDD females and inbred DH (Dh/+) males. Among the newborn pups, the numbers of F1 (Dh/+) males are comparable to those of mice having other genotypes (+/+ male, Dh/+ female and +/+ female), but many F1 (Dh/+) males died before weaning. On the other hand, among the F1 mice from the cross between DH (Dh/+) females and DDD males, there are no biased numbers of Dh genotype pups. These results suggest the existence of defects in the interaction between the male derived Dh gene and the genetic traits of the DDD female.

Summary Organization of the fibre connections in the chick nucleus rotundus (Rt) was investigated by an axonal tracing method using wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). After an injection of WGA-HRP into the Rt, labelled neurones were observed in the striatum griseum centrale (SGC) in both sides of the tectum (TO) and in the ipsilateral nucleus subpretectalis/nucleus interstito-pretecto-subpretectalis (SP/IPS). Labelled fibres and terminals were also found in the ipsilateral ectostriatum (Ect). These fibre connections were topographically organized rostrocaudally. In the TO-Rt projection, the rostral and the dorsocaudal parts of the Rt received afferents from the superficial part of the SGC, the middle part of the Rt received afferents from the intermediate part of the SGC, and the ventrocaudal part of the Rt received mainly fibres from the deep part of the SGC. These topographic projections were accompanied by a considerable number of diffuse projections to the thalamic regions surrounding the Rt. In addition, the rostral and middle caudal parts of the Rt received afferents from the lateral and medial parts of the SP/IPS, respectively, and respective parts of the Rt sent efferents to the lateral and medial parts of the Ect.

Lymphocyte blastogenesis in hairless descendants of Mexican hairless dogs was examined using the following mitogens: phytohemagglutinin (PHA-M), Concanavalin A (Con A), lipopolysaccharide (LPS) and pokeweed mitogen (PWM). Blastogenetic responses to these mitogens were measured by glucose consumption test (GCT) and compared with those of haired beagle dogs. The response to PHA-M was significantly less in the hairless dogs than in the beagles. No significant differences in the responses to Con A, PWM and LPS were recognized. These results indicated T-cell dysfunction in the hairless dogs, coinciding with our previous work showing reduction of the delayed-type hypersensitivity reaction and early degeneration of the thymus.

In the present paper, we applied analysis of the mandible to a new strain of Japanese White rabbit being developed (Nib: JWNS), at 5th and 8th generations (F5 and F8), and evaluated the process of establishment, making comparison with the parent colonies (I, K and L), and other established JW colonies (A, E, O and R). The mandibles were measured at 12 sites and the data obtained were calculated by principal component analysis and discriminant analysis. As a result of principal component analysis, the parent colonies were found to be close to one another with intermediate size of the mandible and height of condyloid and angular processes, but in F5 and F8 the mandibles were slightly shorter in height and different from those in the parent colonies. On the other hand, results of discriminant analysis revealed that mandibles were discriminated correctly 100% in colonies A, O and R, and 90% in E and I. Colonies A, O, R, E and I were therefore regarded as established strains. In the developing colonies, the discriminant rate was 70% in F5 and 80% in F8. One mandible from F5 and two from F8 were wrongly classified to the parent colony L, which was the lowest discriminant rate among the colonies examined (61.5%). The results of both statistical analyses suggest that the JWNS are almost established at 8th generation as a new strain.

Morphological characterization of the skeletal malformations caused by the Dh gene was carried out. Skeletal preparations from newborn mice of Dh/Dh, Dh/+ and +/+ genotypes, and adult Dh/+ mice were examined. The Dh gene induced skeletal deformities at the axial regions from the thorax to the tail. Attachment of the ribs to the sternum was sometimes irregular, and normal segmentation of the sternum was also disrupted. Abnormal fusion of the ventral part of the rib was observed in some cases. Lumbar vertebrae were fewer in number and abnormal in shape. Although it was rare, a curled tail was also observed due to distortion of the caudal vertebrae.

Strain identification and the assessment of genetic relationships among inbred strains of mice were examined by DNA fingerprinting using M13 phage DNA as a probe. We used 8 inbred strains (NC/Jah, DDD/Jah, DSD/Jah, RR/Jah, SS/Jah, C3H/HeJah, C57BL/6 Jah and C57BL/6CrSlc) and coisogenic (NC-brp) as well as congenic (C57BL/6-bg) strains. DNA fingerprints using M13 phage DNA as a probe revealed identical patterns within strains. Bands due to new mutations in minisatellite regions within each strain were not observed. The banding patterns were strain-specific. Thus, DNA fingerprinting seemed to be suitable for genetic monitoring of mice. A dendrogram constructed with difference values calculated from DNA fingerprint patterns showed that relationships among strains reflected the history of these strains, so DNA fingerprinting could also be effectively used to assess the relationships between inbred strains of mice.

SMXA recombinant inbred (RI) strains were derived from the F2 generation of a cross between two progenitor inbred strains, A/J and SM/J, which differ considerably with respect to many characters. In order to determine the morphometric profiles of the mandible of SMXA RI strains and to identify these strains, principal component and discriminant analyses (mandible analysis) were carried out using 11 mandible measurements. Principal component analysis revealed that the mandibles of each strain have their own characteristic size and shape. The RI strains, however, were roughly divided into 15 groups based on the morphometric profile of their mandibles. Discriminant analysis showed the probability of erroneous discrimination to be 6.49% (20/308) for the males and 8.06% (27/335) for the females. In both sexes, most of the erroneous discrimination (13 in the male, 17 in the female) occurred between RI strains having comparatively similar morphometric profiles. This suggested that all of the SMXA RI strains examined could be regarded as genetically homogeneous within each strain.

Ultrastructural changes of the cells forming germinal centers were examined in the chick spleen after intravenous injection of sheep red blood cells. The germinal center was formed by a cluster of large lymphoid cells and a septum of flattened reticular cells. The large lymphoid cell was characterized by numerous polysomes and a large euchromatic nucleus with a prominent nucleolus. In the developing germinal center the large lymphoid cells proliferated and became smaller in size. After the peak of development of the center they were gradually atrophied and finally became degenerative to exhibit pyknotic nuclei, condensed cytoplasm, some vacuoles and many cytoplasmic processes. From the formation of the germinal center through its degeneration, the transformation of lymphoid cells into plasma cells did not occur within the center. Plasma cells were appeared in the red pulp prior to the germinal center formation, and then they proliferated to aggregate around a periarterial lymphatic sheath.

The splenic microcirculation of the White Leghorn chicken was studied by means of the scanning and transmission electron microscopes. Corrosion casts of the splenic vascular network and tissues of the perfused spleen were examined. The corrosion cast presented the passageway of blood in the spleen, in which arterial vessels became veins as continuous canals. The intervening portions connecting both vessels varied in diameter and exhibited tortuous contours. In the perfused spleen, no direct continuity with a continuous endothelium was recognized between the arterial termination and the primordial vein. There was a spongework consisting of reticular cells in the pulp cord. The arterial terminal cepillary opened into the interstice of the spongework. Blood cells remaining in it drained into a venous vessel through the preformed apertures of this vessel.

Morphometrical observations were carried out on the mandibles of chimeras made from the embryos of C57BL/6 and BALB/c mice to compare with the two strains and their reciprocal F1 crosses. The results of the principal component analysis indicate that the first principal component (PC1) and the second principal component (PC2) extracted might be acceptable as size and shape factors, respectively. Variations of both PC1 and PC2 were generally larger in the chimeras than in the two component strains and their F1 crosses. The mean PC1 value of the chimeras was larger than that of the two component inbred strains, and it was similar to that of F1 crosses, or slightly larger. The overall size of the mandible represented by PC1 tended to be larger in the chimeras consisting of two component cells that were approximately equivalent than in those that shifted to either cell population. The above trend was observed in both sexes. These results indicate that chimeric heterosis due to the interaction between genetically different cells (C57BL/6 and BALB/c) has some relation to mandible size. The mean PC2 value, which was accepted as shape factor, was intermediate between the two inbred strains. The mandible size (PC1) and shape (PC2) were bilaterally symmetrical, except for the shape in the female chimeras and in (C57BL/6 x BALB/c)F1.