Changes in the distribution of labeled retinal ganglion cells after an implant of DiI into the optic nerve in the chick embryos

Changes in the distribution of retinal ganglion cells (RGCs) were studied using the retrograde labeling of DiI in chicks and chick embryos. The small retinal area filled with labeled RGCs was observed in the retinal fundus on E8. The labeled retinal area expanded radially toward the peripheral retina as the retina grew, and finally occupied a whole retina by P1. The temporal retina was labeled more rapidly than in the nasal retina. The observed-increasing rate of the labeled area was corrected with the growing rate of the retina. Consequently, the corrected-increasing rate of the labeled area was estimated to be about 390% between E8 and E11, and 20-50% after E11. This means that spreading speed of the maturated RGCs lowered until 1/10-1/20 after E11.     

Studies of certain factors affecting the microenvironment and microflora of the external ear of the dog in health and disease

A total of 187 dogs, 110 with clinical signs of otitis externa (OE), and 77 without history or clinical signs of OE, were examined microenvironment and microbiological analysis of their ear exudates made. The aural temperature and humidity of 160 dogs were measured. There were no significant difference between healthy dogs and OE dogs. German shepherd showed relatively lower temperature (p<0.01) and higher humidity (p<0.01). The mean log(10) number of microbial organisms of ears of OE dogs (4.16 +/- 0.31 cfu/g) was significantly increased, compared to that from the ears of non-OE group (2.55 +/- 0.24 cfu/g). Pseudomonas spp. and Proteus spp. were detected only from OE dogs. In addition, three enterotoxigenic Staphylococcus aureus were isolated from ear specimens.     

Histological disorders related to the focal disappearance of the epiphyseal growth plate in rats induced by high dose of vitamin A

The histological disorders related to the focal disappearance of the epiphyseal growth plate were examined histochemically in the proximal tibia of rats administered a high dose of vitamin A. Animals were given 100,000 IU/100 g body weight/day of vitamin A for 5 days from 4 weeks after birth (VA rats) or given deionized water as control and sacrificed on Day 12 and 19 of the experiment. Tibiae were examined by immunohistochemistry for type I, II and X collagens, lectin-histochemistry for Helix pomatia and backscattered electron imaging. On Day 12, the abnormally developed calcified cartilage matrix was detected within the epiphyseal growth plate in VA rats. The uncalcified cartilage matrix contained type I collagen but lacked type II collagen. In addition, the eroded regions accompanied with numerous osteoclasts and osteoblasts were detected in the epiphyseal growth plate. On day 19, eroded regions penetrated the epiphyseal growth plate to result in its focal disappearances with the eroded surfaces entirely covered with bone tissue in VA rats. These findings suggested that the cartilage matrix of the epiphyseal growth plate was abnormally calcified and showed the phenotypes like bone matrix. The eroded regions of the epiphyseal growth plate seemed to be caused by the invasion of osteoclasts into the altered cartilage matrix and might develop to the focal disappearances by the modeling or remodeling due to action of osteoclasts and osteoblasts.     

Estrogen regulates the serum level of phosphorylated prolactin in mice

Phosphorylated prolactin (PPRL) is considered to be the most quantitatively important post-translationally modified form of prolactin (PRL) in rodents. We recently detected two different types of PPRL in the mouse pituitary gland; one was phosphorylated at serine and the other was phosphorylated at serine/threonine. Furthermore, we showed that there are obvious differences in the ratios between PPRLs and non-phosphorylated PRL in the pituitary gland based on age and sex and that estrogen influences PRL phosphorylation at serine in female mice. In the present study, we examined whether estradiol (E2) increases serine PPRL in the male pituitary gland in the same manner as in the female pituitary gland and examined whether PPRL is released into serum. We first determined the relative amounts of intrapituitary PPRLs in male mice under different pharmacological conditions that increased PRL secretion. The results indicated that treatment with E2 increases serine PPRL. We then performed two-dimensional electrophoresis and immunoblotting analysis after immunoprecipitation with anti-mouse PRL antibody using male and female sera under different pharmacological conditions that increased PRL secretion. The results of this experiment indicated that there were PRLs phosphorylated at serine and serine/threonine in the female serum but not in the male serum. The levels of PPRLs in sera were greatly increased with the E2 treatment for both male and female sera. Furthermore, we examined the effect of E2 on PPRL synthesis in cultured male pituitary glands. In this experiment, we observed increased serine PPRL synthesis and stronger immunohistochemical staining of PRL cells with E2 treatment. These findings suggested that serine PPRL synthesis and secretion were influenced by estrogen.     

Expression profiling of mouse placental lactogen II and its correlative genes using a cDNA microarray analysis in the developmental mouse placenta

The placenta is a highly differentiated organ essential for embryonic growth and development. In order to search for key molecules that are associated with mouse placental lactogen II (mPL-II) gene expression, we applied mouse cDNA microarray analysis to RNAs extracted from placentae on days 10, 12, 14, 16 and 18 of pregnancy. Changes in gene expression were categorized between days 10 and 12, 12 and 14, 14 and 16 and 16 and 18 of pregnancy. After microarray analysis, which had a minimum detectable fold change for differential expression of 2, we selected 10 genes, Apoa2, Apoc2, Ceacam14, Creg1, Fmo1, Igf2, Slc2a1, Spink3, Spi1-1 and Tpbpa, exhibiting a expression pattern similar to the mPL-II gene. Furthermore, we performed real-time PCR analysis and in situ hybridization (ISH) to find correlative expression genes for the mPL-II gene. From these results, we identified a resemblance in gene expression between mPL-II and Igf2 and selected these genes for performance of double-fluorescence immunohistochemical staining. We colocalized these proteins in labyrinthine trophoblast cells. These results strongly suggest that the expression of mPL-II and Igf2 is highly related to placental development in mice. This large-scale identification of genes regulated during placentogenesis assists in further elucidation of the molecular basis of extraembryonic development and function.     

Molecular cloning of cDNA for equine follistatin and its gene expression in the reproductive tissues of the mare.

A cDNA clone encoding equine follistatin was isolated from an equine ovarian cDNA library. Out of 1.2 x 10(5) independent clones screened, one positive clone was isolated and its cDNA sequence determined. The isolated clone, named EQ-FS-1, contained a complete open reading frame encoding 344 amino acid residues. The similarity of its deduced amino acid sequence to these of other mammalian species was greater than 95%. Although its expression level varied among the tissues examined, follistatin mRNA was detected in the equine uteroplacental tissues, follicles and corpora lutea by Northern blot analysis. In situ hybridization revealed that the expression of follistatin mRNA in the equine follicle was restricted exclusively to granulosa cells. When the expression pattern of follistatin mRNA in the equine uteroplacental tissues from mid- to late-pregnancy was examined, it was shown that its expression level tended to decrease after mid-pregnancy. These results suggest that follistatin acts in the reproductive tissues of the mare in maintaining pregnancy.