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Biomedical subjects

E Kobayashi

Publications and source records attributed to E Kobayashi.

480 records · Page 27Linked to original sources
PubMedDate not supplied

Can a bone marrow cell contribute to organ regeneration? In vivo analysis using transgenic rats with reporter genes.

Although implantation of multipotent bone marrow-derived stem cells represents an attractive new cell therapy to repair damaged tissues, recent reports have raised serious concerns over the feasibility of using stem cells deriving from the bone marrow to promote cell transdifferentiation. We established transgenic (Tg) rats with reporter genes as specific molecular tags to examine the effect of bone marrow cells (BMCs) on transdifferentiation into tissues/organs. To monitor transdifferentiation events of locally transplanted BMCs into hepatocytes or capillary endothelial cells, a liver injury model and an ischemic hind-limb model were developed in rats. To test the ability of circulating bone marrow-derived cells to give rise to myocytes after skeletal muscle injury, we used a bone marrow cell transplantation model from Tg rats, which showed ubiquitous expression of beta-galactosidase (lacZ), into lethally irradiated non-Tg rats. Our results show that there was little transdifferentiation of BMCs into the targeted cells in these tissue injury models. However, in the ischemic hind-limb model, laser Doppler imaging and histologic analysis showed that both implantation of BMCs and treatment with microspheres incorporating basic fibroblast-like growth factor (bFGF), which enables the release of bFGF at the site of action over a period of time, effectively induced angiogenesis. In conclusion, rat BMCs with specific marker genes could be a useful tool for detecting transdifferentiation events in vivo.

Animals↗
PubMedDate not supplied

Renal effects of cadmium intake of a Japanese general population in two areas unpolluted by cadmium.

Renal effects of cadmium exposure (i.e., in food products) on people living in two areas unpolluted by cadmium in Japan were investigated. The population comprised 875 inhabitants (i.e., 346 males and 529 females) and 635 inhabitants (i.e., 222 males and 413 females), all of whom in each area were 50+ y of age. The authors used urinary cadmium concentration as an indicator of internal dose, and total urinary protein, beta2-microglobulin, and N-acetyl-beta-glucosaminidase were indicators of renal dysfunction. The authors used multiple-regression and logistic-regression analyses to study the relationship between urinary cadmium excretion and the above indicators of renal dysfunction. In the two geographic areas, both analyses revealed that urinary cadmium concentrations were associated significantly with indicators of renal dysfunction. The results suggest that renal dysfunction is related significantly with environmental cadmium exposure in areas of Japan that are not polluted by cadmium.

Acetylglucosaminidase↗
PubMedDate not supplied

Dose-response relationship between urinary cadmium concentration and beta2-microglobulinuria using logistic regression analysis.

Logistic regression analysis was used to investigate the dose-response relationship for environmental cadmium exposure and to consider the effect age had on this association. The target population comprised 3178 inhabitants of Japan who were more than 50 y of age and who lived in a cadmium-polluted area and 1134 inhabitants who lived in nonpolluted areas of Japan. Logistic regression analysis was completed on the dose-response relationship between urinary cadmium concentration (i.e., an indicator of cadmium body burden) and beta2-microglobulinuria (i.e., an index of renal tubular dysfunction caused by exposure to cadmium). Both age and urinary cadmium concentration were associated significantly with beta2-microglobulinuria. Based on the relationship that was determined, we calculated, by age and sex, the values of urinary cadmium concentration that corresponded to the prevalence rates of beta2-microglobulinuria in the nonpolluted population. The resulting values were 1.6-3.0 micrograms/g creatinine for men and 2.3-4.6 micrograms/g creatinine for women.

Age Factors↗
PubMedDate not supplied

Segmental small bowel transplantation in the rat: comparison of lipid absorption between jejunal and ileal grafts.

BACKGROUND: From the immunological point of view, it is very important to evaluate the efficacy of segmental small bowel transplantation and to determine which part of the intestine, jejunum, or ileum should be used. In the present study, we investigated the absorptive function of the transplanted jejunum and ileum in the rat. METHODS: Syngeneic segmental small bowel transplantation (jejunal or ileal grafting) was performed. After surgery, body weight and fecal fat excretions were measured. In addition, bile acid concentration in bile juice was measured, and the response of both serum lipase and bile flow rate after oleic acid stimulation was evaluated. Recanalization of the lymphatic vessels was investigated by lymphangiography. RESULTS: There was no significant difference in body weight change between normal controls, jejunum-transplanted rats, and ileum-transplanted rats. In short gut rats, however, body weight was significantly impaired. Fecal fat excretion in short gut rats was the highest in the four groups, and it was significantly lower in ileal grafts than in jejunal grafts. Ileum-transplanted rats also showed a significantly higher bile acid concentration in bile juice than jejunum-transplanted rats. After oleic acid stimulation, serum lipase responded better in ileal transplants than in jejunal transplants, but the bile flow rate did not show significant change in either group. Recanalization of the lymphatic vessels was established on the 28th postoperative day. CONCLUSIONS: These results clearly show that ileal transplantation is more conducive to lipid absorption than jejunal transplantation.

Animals↗
PubMedDate not supplied

Comparative changes in the liver of female Fischer-344 rats after short-term feeding of a semipurified or a semisynthetic L-amino acid-defined choline-deficient diet.

Groups of female Fischer-344 rats were fed a semipurified choline-deficient (CD) diet, or a semisynthetic L-amino acid-defined choline-deficient (CDAA) diet, for up to 12 wk and effects of the 2 diets on the liver were compared. Steatosis was diffuse and more severe throughout in rats fed the CDAA diet than in rats fed the CD diet. Greater elevations in serum aspartate and alanine aminotransferase activities were also present in the former rats, along with higher 2-bromodeoxyuridine labeling indices in the liver. Discrete amounts of 8-hydroxyguanine were detected in liver DNA, but were not significantly different in rats fed the 2 diets, or from those present in a group of control rats killed at 0 time. Glutathione S- transferase placental form-positive focal lesions were not observed in any of the rats. The results show that the CDAA diet causes more severe degrees of steatosis and liver cell death and proliferation than the CD diet, raising the possibility that it may, in contrast to the CD diet, result in the eventual induction of hepatocellular carcinomas in female Fischer-344 rats.

Alanine Transaminase↗
PubMedDate not supplied

MR imaging of diffuse glioma.

Neuroradiologic diagnosis of "gliomatosis cerebri" is hampered by the diffuse, isodense character of the lesion, and the fact that it may not enhance when intravenous contrast medium is administered. Clinical signs and symptoms are usually nonspecific, nonfocal, and disproportionately mild. We report a case of diffuse glioma in a 30-year-old man, discuss the difficulty in arriving at a precise diagnosis of gliomatosis cerebri, and examine the possible role of MR in its detection and delineation.

Adult↗
PubMedDate not supplied

Suppression by protein kinase C inhibitors of tumor promoter enhancement of Epstein-Barr virus-induced growth transformation.

The tumor promoter teleocidin activates latent Epstein-Barr virus (EBV) genomes and enhances EBV-induced growth transformation of human B cells, with an activity comparable to that of 12-O-tetradecanoyl-phorbol-13-acetate (TPA). It has been suggested that the TPA induction of EBV genomes is mediated by protein kinase C (PKC), an enzyme closely linked to signal transduction. We examined newly isolated, highly selective PKC inhibitors, UCN-01 (7-hydroxyl-staurosporine) and calphostin C, for the possible suppression of teleocidin enhancement of cord blood B lymphocyte growth transformation by EBV. 0.2 nM teleocidin B4 enhanced EBV-induced 3H-thymidine uptake 6 times, outgrowth in limiting dilution culture 5 times, and colony formation in semisolid agar 3 times. All these events were suppressed by exposure to 10-100 nM UCN-01 or to calphostin C. Our findings suggest that the tumor promoter enhancement of EBV growth transformation is probably mediated by PKC.

Alkaloids↗