Neonatal mouse testis-derived multipotent germline stem cells improve the cardiac function of acute ischemic heart mouse model

Multipotent germline stem (mGS) cells have been established from neonatal mouse testes. We previously reported that undifferentiated mGS cells are phenotypically similar to embryonic stem cells and that fetal liver kinase 1 (Flk1)⁺ mGS cells have a similar potential to differentiate into cardiomyocytes and endothelial cells compared with Flk1⁺ embryonic stem cells. Here, we transplanted these Flk1⁺ mGS cells into an ischemic heart failure mouse model to evaluate the improvement in cardiac function. Significant increase in left ventricular wall thickness of the infarct area, left ventricular ejection fraction and left ventricular maximum systolic velocity was observed 4 weeks after when sorted Flk1⁺ mGS cells were transplanted directly into the hearts of the acute ischemic model mice. Although the number of cardiomyocytes derived from Flk1⁺ mGS cells were too small to account for the improvement in cardiac function but angiogenesis around ischemic area was enhanced in the Flk1⁺ mGS cells transplanted group than the control group and senescence was also remarkably diminished in the early phase of ischemia according to β-galactosidase staining assay. In conclusion, Flk1⁺ mGS cell transplantation can improve the cardiac function of ischemic hearts by promoting angiogenesis and by delaying host cell death via senescence.     

Inter-annual variation in the response of leaf-out onset to soil moisture increase in a teak plantation in northern Thailand

To understand the impact of inter-annual climate change on vegetation-atmosphere mass and energy exchanges, it has become necessary to explore changes in leaf-out onset in response to climatic fluctuations. We examined the response of leaf-out and transpiration onset dates to soil moisture in a teak plantation in northern Thailand based on a 12-year leaf area index and sap flow measurements. The date of leaf-out and transpiration onset varied between years by up to 40 days, and depended on the initial date when the relative extractable water in a soil layer of 0–0.6 m (Θ) was greater than 0.2 being consistent with our previous results. Our new finding is that the delay in leaf-out and transpiration onset relative to the initial date when Θ?>?0.2 increases linearly as the initial date on which Θ?>?0.2 becomes earlier. The delay spans about 20 days in years when Θ?>?0.2 occurs in March (the late dry season)—much earlier than usual because of heavy pre-monsoon rainfalls—while there is little delay in years when Θ?>?0.2 occurs in May. This delay indicates the influence of additional factors on leaf-out onset, which controls the delay in the response of leaf-out to soil moisture increase. The results increased our knowledge about the pattern and extent of the changes in leaf phenology that occur in response to the inter-annual climate variation in tropical regions, where, in particular, such research is needed.     

A phase-locking theory of matching between rotated images by dynamic link matching

Pattern recognition invariant to deformation or translation can be performed with the dynamic link matching proposed by von der Malsburg. Dynamic link matching has been applied to some engineering examples efficiently, but has not yet been analyzed mathematically. We propose two models of dynamic link matching, both of which are mathematically tractable. The first model can perform matching between rotated images. The second model can also do that and additionally detect common parts in a template image and in a data image. To analyze these models mathematically, we reduce each model's equation to a phase equation, showing the mathematical principle behind the rotating invariant matching process. We also carry out computer simulations to verify the mathematical theories involved. Received: 23 July 1987 / Accepted in revised form: 12 January 1998     

Purification and properties of multiple forms of mouse trypsinogen

Three trypsinogens and one chymotrypsinogen were found in and purified from the pancreas of a mouse strain (CFO). The molecular weights of the trypsinogens and the chymotrypsinogen were all estimated as 25 000. The enzyme properties of the three trypsinogens were studied and they showed very low K_m values (3.2?6.5 μM) for the substrates, BzArgOEt and TosArgOMe, and the dame pH optimum profile between pH 8.0–10.0. However, the ratios of catalytic rate constants, k_cat (s^?1), with BzArgOEt as substrates compared to that with TosArgOMe were very different. The values of Try-III were similar with the two substrates, Try-I was slightly higher value with TosArgOMe than with BzArgOEt, and the values of Try-II were much higher with TosArgOMe than with BzArgOEt. Also, the trypsinogens and the chymotrypsinogen were purified from pancreas of Mol-A strain mice. When the enzyme properties of the three trypsinogens were examined, one form of trypsinogen (Try-I) was shown to have different properties in k_cat (s^?1) for the two substrates, compared to the trypsinogen of CFO mice.     

The Effects of Organic Solvent on the Ribosyl Transfer Reaction by Thermostable Purine Nucleoside Phosphorylase and Pyrimidine Nucleoside Phosphorylase from Bacillus stearothermophilus JTS 859

The effects of organic solvents on the reaction rate and equilibrium of the ribosyl transfer reaction catalyzed by thermostable purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase from Bacillus stearothermophilus JTS 859 were examined at 60°C. The reaction rate in the presence of 10% acetone was 1.6 times higher than that of the control. Acetone was the best organic solvent among those tested for accelerating the reaction rate without denaturing the enzymes. On the other hand, the reaction rate in the presence of 5% ethyl acetate was 1.5 times higher than that of the control. However the enzymes were denatured completely after 1 h incubation. Consequently, the acceleration was not attributed to the stabilization of the enzymes. The equilibrium constants of the reaction were not influenced by the presence of acetone, methyl or ethyl alcohols.     

An Electron Microscopic Study on Spermatogenesis in Golfingia ikedai

The process of spermatogenesis in Golfingia ikedai was observed with electron microscope. Clusters of primary spermatocytes continued spermatogenesis while floating in the body fluid. No direct connections were found between the cells and no cytophore formation was observed. Preacrosomal vesicles were formed from small Golgi-bodies just after the meiosis. Subacrosomal substances were aggregated just under the acrosomal vesicle in the middle stage of spermiogenesis and changed into fibrous structures in the completed spermatozoon. A peculiar annulus structure developed around the base of the flagellum. The phylogenetic position of this worm was also discussed in relation to the polychaetes and other worms.     

Antigenic heterogeneity of the reticular meshwork in the white pulp of mouse spleen

Summary Monoclonal antibodies against cellular components of reticular meshworks were produced by immunizing rats with heterogeneous stromal-cell population of mouse spleen. Immunohistochemical screening selected two antibodies, WP-1 and RPSC-2. WP-1 proved to immunostain the meshwork of the B area densely, leaving the marginal zone unstained; it also reacted sparsely with the meshwork of the T-cell region. In contrast, RPSC-2 selectively immunostained the meshwork of the T region. Immuno-electron microscopy clearly visualized, for both antibodies, reaction products being deposited along the cytomembrane of the fibroblastic reticulum cells, along their abundant cytoplasmic processes that were densely intertwined with lymphocytes. Double immunostaining with RPSC-2 followed by WP-1 clearly divided the white pulp into the T and the B domains. The meshwork in the T-cell region proved to be immunostainable with both WP-1 and RPSC-2. Thus, the fibroblastic reticulum cells of the T-and the B-cell areas, while indistinguishable by routine microscopy, are at least partially heterogeneous.Presented at the First International Symposium on Dendritic Cells in Lymphoid Tissues, held in Yamagata, Japan, 7–9 June, 1990     

A Mixture of Paraphenylenediamine and Imidazole: Its Effect on the Extraction of Lipid Droplets during Electron Microscopy Staining

To prevent extraction of lipids during a double staining procedure for electron microscopy, the tissue slices, double fixed with glutaraldehyde and osmium tetroxide to preserve microvesicular lipid droplets in the cytoplasm, were immersed for 2 hr in veronal buffer (pH 9.0) containing 0.5% p-phenylenediamine and 0.5% imidazole immediately after postfixation. The stained sections of the immersed tissue slice showed blackened, well circumscribed lipid droplets similar to those in corresponding unstained sections. Moreover, highly contrasting features of the cellular architecture could be visualized with the double stained, as well as routinely prepared sections.     

Apoptosis and cell desquamation in repair process of ischemic tubular necrosis

To elucidate the role of apoptosis and cell desquamation in the repair phase of acute tubular necrosis, morphological findings after 60 min ischaemia were investigated in rats. A morphometric analysis of the cell proliferation and of the epithelial cellularity of reconstructing tubules was performed. The kinetics of apoptosis and cell desquamation were also examined. Ischaemia and reperfusion injury resulted in widespread necrosis of tubules at day 1. Subsequently, a regenerative epithelial hyperplasia took place in the aarly stage. The most marked increase in cellularlity in the damaged tubules was on day 6, when the tubules became lined by hyperplastic epithelial cells with papillary clusters. The number of papillary clusters decrease up to day 8, and during this period many desquamated cells from the clusters were observed in the tubular lumen. In the later stage, hyperplastic epithelial cells were reduced to their original cellularity and during this period the number of apoptotic cells obviously increased, while the damaged tubules were reconstructed. We conclude that epithelial over-production occurs in the early phase after tubular necrosis, and excess hyperplastic epithelial cells regress during the repair process by cell desquamation and apoptosis, both of which are essential for the recovery of the original tubular structure.