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71.
A dye injection method was used to elucidate the xylem water-conducting pathways of 34 broadleaved evergreen trees growing in southern Japan: two semi-ring-porous, 26 diffuse-porous, five radial-porous and one non-vessel species. The large earlywood vessels in semi-ring-porous species have a water transport function in only the outermost annual ring, as in deciduous ring-porous species. On the other hand, the small vessels in semi-ring-porous species maintain the water transport function in many outer annual rings. For the other xylem-type species, the many vessels in many outer annual rings have a water transport function. In diffuse-porous species, we categorized the water-conducting pattern within the annual rings into two types: d1 type, where water travels through vessels in the whole region; and d2 type, where water travels mainly through the earlywood vessels. The pattern in radial-porous species is similar to that in the d1 type; the pattern in non-vessels species is similar to that in the d2 type. The vessel diameter in radial-porous species is similar to that of the earlywood vessels of semi-ring-porous species. These results suggest that the conduit diameter size is only one of many factors determining the water-conducting pathways of broadleaved evergreen species.  相似文献   
72.
73.
Hepatocyte growth factor (HGF) is a potent mitogen for various epithelial cells, including mature hepatocytes and renal tubular cells. Here, HGF mRNA was found to be markedly increased in non-injured kidney and spleen, when the liver or kidney in rats was injured by 70% partial hepatectomy or unilateral nephrectomy. HGF mRNA increased to 3-4 fold higher level than the normal in the kidney and spleen as well as in the remnant liver after partial hepatectomy. Similarly, HGF mRNA markedly increased in the spleen as well as in the remnant kidney after unilateral nephrectomy. These results suggest that the onset of injury to the liver or kidney may be recognized by distal non-injured organs by the signalling of a humoral factor and that HGF derived from these organs may be involved in the regeneration of liver or kidney, through an endocrine mechanism.  相似文献   
74.
We assessed vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza in children 6 months to 15 years of age in 22 hospitals in Japan during the 2013–14 season. Our study was conducted according to a test-negative case-control design based on influenza rapid diagnostic test (IRDT) results. Outpatients who came to our clinics with a fever of 38°C or over and had undergone an IRDT were enrolled in this study. Patients with positive IRDT results were recorded as cases, and patients with negative results were recorded as controls. Between November 2013 and March 2014, a total of 4727 pediatric patients (6 months to 15 years of age) were enrolled: 876 were positive for influenza A, 66 for A(H1N1)pdm09 and in the other 810 the subtype was unknown; 1405 were positive for influenza B; and 2445 were negative for influenza. Overall VE was 46% (95% confidence interval [CI], 39–52). Adjusted VE against influenza A, influenza A(H1N1)pdm09, and influenza B was 63% (95% CI, 56–69), 77% (95% CI, 59–87), and 26% (95% CI, 14–36), respectively. Influenza vaccine was not effective against either influenza A or influenza B in infants 6 to 11 months of age. Two doses of influenza vaccine provided better protection against influenza A infection than a single dose did. VE against hospitalization influenza A infection was 76%. Influenza vaccine was effective against influenza A, especially against influenza A(H1N1)pdm09, but was much less effective against influenza B.  相似文献   
75.
Polar cod, Boreogadus saida, is a key species in the Arctic Ocean ecosystem. We examined the distribution pattern of B. saida and other fish larvae in relation to oceanographic parameters, including sea surface temperature and salinity (SST and SSS), the mode of temperature and salinity within the water column (F temp and F sal), and the temporal duration between the date of sea ice retreat and the date of field surveys (dSRT) in the northern Bering Sea and Chukchi Sea during the summers of 2008 and 2013. Sampling was conducted onboard the T/S Oshoro-Maru using a bongo net for 2 years. At sampling stations, the temperature and salinity were measured using conductivity-temperature-depth profiler casts. We calculated dSRT from satellite derived polar gridded sea ice concentration data. A total of 1186 individuals comprising 7 families and 16 species were collected, with B. saida (35 %) and Ammodytes hexapterus (27 %) dominating the catch in number. Based on the species composition (cluster analysis), the sampling stations were divided into four groups. Pleuronectidae dominated group A, which was characterized by relatively high temperature (SST and F temp), while B. saida dominated group B, characterized by low temperatures. A. hexapterus dominated group C and D, which had similar temperatures and salinities, but group C had a shorter dSRT than group D. The latter was also differentiated by the presence of Lumpenus sp. B. saida, which were most abundant in regions where temperatures ranged from ?2 to 0.5 °C. These results, the geographical variation of group B sampling stations, suggest there are two separate spawning areas characterized by similar fish communities and related to consistently cold bottom temperatures. Moreover, stations with a higher abundance of smaller sized larval B. saida were characterized by a short dSRT, whereas stations with a lower abundance and a larger size were characterized by a long dSRT.  相似文献   
76.
Polyamidoamine dendrimers having poly(ethylene glycol) grafts were designed as a novel drug carrier which possesses an interior for the encapsulation of drugs and a biocompatible surface. Poly(ethylene glycol) monomethyl ether with the average molecular weight of 550 or 2000 was combined to essentially every chain end of the dendrimer of the third or fourth generation via urethane bond. The poly(ethylene glycol)-attached dendrimers encapsulating anticancer drugs, adriamycin and methotrexate, were prepared by extraction with chloroform from mixtures of the poly(ethylene glycol)-attached dendrimers and varying amounts of the drugs. Their ability to encapsulate these drugs increased with increasing dendrimer generation and chain length of poly(ethylene glycol) grafts. Among the poly(ethylene glycol)-attached dendrimers prepared, the highest ability was achieved by the dendrimer of the fourth generation having the poly(ethylene glycol) grafts with the average molecular weight of 2000, which could retain 6.5 adriamycin molecules or 26 methotrexate molecules/dendrimer molecule. The methotrexate-loaded poly(ethylene glycol)-attached dendrimers released the drug slowly in an aqueous solution of low ionic strength. However, in isotonic solutions, methotrexate and adriamycin were readily released from the poly(ethylene glycol)-attached dendrimers.  相似文献   
77.
Artificial induction of active DNA demethylation appears to be a possible and useful strategy in molecular biology research and therapy development. Dimethyl sulfoxide (DMSO) was shown to cause phenotypic changes in embryonic stem cells altering the genome-wide DNA methylation profiles. Here we report that DMSO increases global and gene-specific DNA hydroxymethylation levels in pre-osteoblastic MC3T3-E1 cells. After 1 day, DMSO increased the expression of genes involved in DNA hydroxymethylation (TET) and nucleotide excision repair (GADD45) and decreased the expression of genes related to DNA methylation (Dnmt1, Dnmt3b, Hells). Already 12 hours after seeding, before first replication, DMSO increased the expression of the pro-apoptotic gene Fas and of the early osteoblastic factor Dlx5, which proved to be Tet1 dependent. At this time an increase of 5-methyl-cytosine hydroxylation (5-hmC) with a concomitant loss of methyl-cytosines on Fas and Dlx5 promoters as well as an increase in global 5-hmC and loss in global DNA methylation was observed. Time course-staining of nuclei suggested euchromatic localization of DMSO induced 5-hmC. As consequence of induced Fas expression, caspase 3/7 and 8 activities were increased indicating apoptosis. After 5 days, the effect of DMSO on promoter- and global methylation as well as on gene expression of Fas and Dlx5 and on caspases activities was reduced or reversed indicating down-regulation of apoptosis. At this time, up regulation of genes important for matrix synthesis suggests that DMSO via hydroxymethylation of the Fas promoter initially stimulates apoptosis in a subpopulation of the heterogeneous MC3T3-E1 cell line, leaving a cell population of extra-cellular matrix producing osteoblasts.  相似文献   
78.
79.
Development of vitrified mouse oocytes after in vitro fertilization   总被引:4,自引:1,他引:4  
Mouse oocytes were cryopreserved by the vitrification method using vitrification solution (VSI) and the effects of dilution methods were examined on the rate of in vitro and in vivo development. Eighty-three percent and 75% of vitrified oocytes exhibited normal morphology when diluted in glycerol + sucrose and sucrose alone, respectively. In contrast, only 35% of the oocytes diluted by a stepwise method exhibited a normal appearance. A high proportion of vitrified oocytes was fertilized in vitro (84-94%), 80 to 87% of which were normal. Of the later embryos, 69 to 78% developed to blastocysts after 4 days of culture. Thirty-six live young (51%) were obtained when vitrified oocytes were transferred to recipient females. The overall rate of development to live young was 25% when vitrified oocytes were diluted with glycerol + sucrose solution. These results indicate that the simple and rapid procedure of vitrification and glycerol + sucrose dilution is suitable for the cryopreservation of mouse oocytes.  相似文献   
80.
Collagen, which is used as a biomaterial, is the most abundant protein in mammals. We have previously reported that a dendrimer modified with collagen model peptides, (Gly‐Pro‐Pro)5, formed a collagen‐like triple‐helical structure, showing thermal reversibility. In this study, various collagen‐mimic dendrimers of different generations and at different binding ratios were synthesized, to investigate the relationship between the peptide clustering effect and the higher order structure formation. The formation of the higher order structure was influenced by the binding ratios of the peptide to the dendrimer, but was not influenced by the dendrimer generation. A spacer, placed between the dendrimer terminal group and the peptide, negatively contributed to the formation of the higher order structure. The collagen model peptides were also attached to poly(allylamine) (PAA) and poly‐L ‐lysine (poly(Lys)) to compare them with the collagen‐mimic dendrimers. The PAA‐based collagen‐mimic compound, bearing more collagen model peptides than the dendrimer, exhibited a thermally stable higher order structure. In contrast, this was not observed for the collagen‐mimic polymers based on poly(Lys). Therefore, dendrimers and vinyl polymers act as a scaffold for collagen model peptides and subsequently induce higher order structures. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 640–648, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com  相似文献   
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