Salt precipitation during the freeze-concentration of phosphate buffer solutions

Salt precipitation during the freeze concentration of phosphate solutions was investigated by differential scanning calorimetry (DSC), in view of its practical importance in the cryopreservation or freeze-drying of biological materials. It was found that the fraction of salt precipitated depends on the initial salt concentration; it began to decrease with decreasing concentration at approx. 1 M. Salt precipitation also depends on the cooling rate. In some cases, cooling at approx. 10(3) degree min-1 inhibited salt precipitation which had been observed during slow cooling (0.62 degree min-1), without, however, affecting the shape of the ice melting endotherm. In the case of ternary phosphate buffers, the fraction of salt precipitating depends on the salt composition as well as the initial concentration and cooling rate. Near the composition of the ternary eutectic or the composition where two salts are present at the same concentration, salts were prevented from precipitation.     

Infection of Cattle with Parainfluenza 3 Virus with Special Reference to Udder Infection

Thirty-seven strains of parainfluenza 3 virus were isolated on bovine kidney cell cultures from Japanese cattle in herds suffering from acute respiratory illness. This finding, together with the clinical and epidemiologic observations and the results of a serologic survey, indicates that in Japan, as in the United States and other countries, this virus is one of the important causes of acute respiratory disease in cattle. A significant finding in the present study is that virus was recovered from milk as well as from nasal secretions. This finding suggests an important role for milk, along with nasal discharges, in disseminating the virus among cattle. In addition, the recovery of virus from milk presents a new problem concerning this infection in cattle, in particular, the potential role of this virus in the pathogenesis of mastitis.     

Community structure and short temporal stability of a rockpool fish assemblage at Yaku-shima Island, southern Japan, northwestern Pacific

The present study investigated species richness, relative abundance, and short temporal variability of rockpool fish communities on the southwestern coast of Yaku-shima Island, northwestern Pacific. In total, 2,850 fish (total biomass approximately 3,400 g) representing 17 families and 54 species were collected from 16 rockpools from May 2009 to February 2010. Gobiidae (12 species), Blenniidae (10), Pomacentridae (6), and Labridae (5) were the dominant families; Blenniidae was the most abundant family (57.1 % of the total number of fish), followed by Gobiidae (30.1 %), Tripterygiidae (5.3 %), Labridae (3.2 %), and Pomacentridae (2.4 %). The Blenniidae accounted for more than 80.0 % of the community biomass. This dominance of Blenniidae and Gobiidae in the community reflects their diversity in the western Pacific and ability to adapt to rocky intertidal habitats. The mean density and species richness of rockpool fish decreased significantly in winter. This is attributed to a decrease in recruitment of transient and accidental visitor species into the rockpool environments, which in turn was due to a significant decline in water temperature in winter. However, mean diversity index (Simpson’s D) did not vary significantly across the seasons, because over 80.0 % of the total number of individuals in each season was from six common species (three blenniids, two gobiids, and a tripterygiid). It can be concluded that the community composition is generally stable over short time-scales. The biogeographic composition of this assemblage was compared with those of two other sites (cited from two past studies) in southern Japanese waters. These other sites were mostly composed of warm temperate species, with regard to the number of species and individuals, while tropical species were predominant in the assemblage at the southwestern coast of Yaku-shima Island. This result suggests that the warm Kuroshio Current has more influence on the Yaku-shima Island coastal fauna than it does on those of the other sites in southern Japanese waters.     

Keratin distribution in precancerous stages of experimental carcinogenesis in mouse submandibular glands

The immunohistochemical distribution of keratin is reported in experimental carcinogenesis in the mouse submandibular gland (SMG). The initial changes included degranulation of granular convoluted tubule (GCT) cells and the appearance of keratin in the degranulated cells. There was a gradual increase in the area showing keratin staining in the altered tubule cells. Duct-like and cystic structures exhibited an intense keratin staining of their lining epithelium. The squamous cell carcinomas induced varying degrees of keratinization and positive immunohistochemical keratin staining. The latter technique provided a useful marker for distinguishing tumor cells of segmental duct origin in the salivary gland.     

Immunohistochemical demonstration of epidermal growth factor and nerve growth factor in experimental carcinogenesis in the mouse submandibular gland

Immunohistochemical demonstration of epidermal growth factor (EGF) and nerve growth factor (NGF) was made during chemical carcinogenesis in the mouse submandibular gland. The granular convoluted tubule cells in the normal male submandibular gland contained larger amounts of EGF and NGF than in the female. The initial phase and early stages in chemical carcinogenesis showed degranulation of the granular convoluted tubule cells with a marked decrease in EGF and NGF. Premalignant lesions such as duct-like structures and multicystic lesions showed variable staining for EGF and were usually negative for NGF. Material secreted into the luminal spaces revealed increased staining for EGF and NGF. Scattered tumor cells of the poorly differentiated squamous-cell carcinoma type and desquamated tumor cells contained abundant EGF, but not NGF. No positive reaction for EGF or NGF was found in the induced squamous-cell carcinoma cells.     

Possible circulation of H5N1 avian influenza viruses in healthy ducks on farms in northern Vietnam

To estimate the prevalence of influenza A subtype H5N1 viruses among domestic ducks in the period between October and November 2006 when H5N1 outbreaks had been absent, 1106 healthy ducks raised in northern Vietnam were collected. Inoculation of all throat and cloacae samples into embryonated eggs resulted in the isolation of subtype H3N8 in 13 ducks, but not H5N1 viruses. Serological analyses demonstrated that five ducks (0.45%) solely developed H5N1 subtype-specific hemagglutinin-inhibiting and neuraminidase-inhibiting antibodies together with anti-non-structural protein 1 antibodies. The results suggested that the ducks were naturally infected with H5N1 viruses when obvious H5N1 outbreaks were absent.