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Biomedical subjects

M Kuwabara

Publications and source records attributed to M Kuwabara.

At least 19 recordsLinked to original sources
PubMed1995

The suppression of age-related accumulation of lipid peroxides in rat brain by administration of Rooibos tea (Aspalathus linearis).

The protective effects of Rooibos tea (RT), Aspalathus linearis, against damage to the central nervous system (CNS) accompanying aging were examined by both the thiobarbituric acid reaction (TBA) and magnetic resonance imaging (MRI) methods in brains of chronically RT-treated rats. Ad libitum administration of RT was begun with 3-month-old Wistar female rats and continued for 21 months. The contents of TBA reactive substances (TBARS) in the frontal cortex, occipital cortex, hippocampus and cerebellum in 24-month-old rats after administration with water were significantly higher than those in young rats (5 weeks old). However, no significant increase of TBARS was observed in RT-administered aged rats. When MR images of the brains of 24-month-old rats with and without RT as well as 5-week-old rats were taken, a decrease of the signal intensity was observed in the cerebral cortex, hippocampus and cerebellum in MR images of aged rats without RT, whereas little change of the signal intensity was observed in MR images of the same regions of 24-month-old rats treated with RT, whose images were similar to those of young rats. These observations suggested that (1) the age-related accumulation of lipid peroxides in the brain was closely related to the morphological changes observed by MRI, and (2) chronic RT-administration prevented age-related accumulation of lipid peroxides in several regions of rat brain.

Administration, Oral↗
PubMed1995

[Enzyme immunoassay (EIA) as an assay system of tumor markers].

To detect a small amount of tumor marker in the serum, the development of a sensitive assay system has been tried. In the beginning radioimmunoassay was mainly employed. But the use of radioisotope has been undesirable because the special facilities to treat radioactive substance or to discard it are required. For this reason the various assay systems without the radioisotope have been developed. Among them EIA system is in the mainstream, especially for the determination of CEA and AFP. Recent analysis shows the increasing trend of the employment of EIA for the determination of other tumor markers. In EIA system it is critical to keep the regulation of reaction time to be obtain the accurate value. Autoassay system is favorable for this problem. It is also another problem that discrepancies of assayed value are seem among the different assay kits. In the clinical use of tumor marker the comparison of the serial data, even if they are obtained from the different hospitals, is important. So overcoming this problem is desirable.

Automation↗
PubMed1993

Development and application of an enzyme immunoassay for tenascin.

A sandwich enzyme immunoassay system for detecting tenascin in human serum was established using purified antibodies to tenascin. The assay system comprises polystyrene balls with immobilized polyclonal antibody F(ab')2 fragments and monoclonal antibody F(ab')2 fragments labeled with beta-D-galactosidase from Escherichia coli. The assay system has a minimum detectable sensitivity of 10 ng/ml of tenascin in human serum, with an assay range of 3 micrograms/ml. The assay system was found not to cross-react with laminin, vitronectin, human epidermal growth factor, fibrinogen, or fibronectin. Coefficients of variation within-run and between-run for the assay of human serum tenascin were less than 10%. Serum samples from healthy adults (n = 86) contained about 800 ng/ml and serum tenascin concentrations of patients with carcinoma (n = 47) were increased. These results suggest that tenascin in serum might be a marker substance for carcinoma.

Adult↗
PubMed1992

[Clinical application of 31P MRS to malignant liver tumors--with an emphasis on evaluation of response to therapy].

Malignant liver tumors in 19 cases (13 hepatomas and 6 metastatic tumors) were studied by 31P magnetic resonance (MR) spectroscopy. Five healthy volunteers were also studied. Volume localization was performed using the ISIS sequence. Compared with normal liver, the MR spectra of malignant tumors showed an elevated phosphomonoester (PME) peak relative to beta ATP (p less than 0.005), and tumors were slightly alkaline (pH 7.32 +/- 0.08) before therapy. Nine cases of hepatomas responding to chemoembolization showed extremely reduced signal intensity of spectra. Tumor pH was compared before and after therapy in four cases that showed good response to therapy, and was elevated in all of them. Three metastatic tumors with good response showed reductions in PME and ATP after therapy. MR spectroscopy with adequate localization technique is useful in demonstrating the response of malignant tumors to therapy.

Carcinoma, Hepatocellular↗
PubMed1992

Deamidation of human erythrocyte protein 4.1: possible role in aging.

The human erythrocyte membrane protein 4.1 exists in two major electrophoretic forms: 4.1a (80 Kd) and 4.1b (78 Kd). Mass spectrometry and amino acid analysis of the proteolytic peptides derived from carboxyl-terminal regions of these proteins indicate that they differ by deamidation of two aspargine residues at positions 478 and 502. Electrophoretic analysis of carboxyl-terminal peptides has shown that the mobility difference between the two polypeptides is due to the deamidation of Asn502 and not that of Asn478. This observation was confirmed by converting a congener of the protein 4.1b to 4.1a by site-directed mutagenesis of Asn502 to Asp. These results unambiguously demonstrate that deamidation of Asn502 is responsible for conversion of protein 4.1b to 4.1a. Since the conversion of protein 4.1b to 4.1a, under physiological conditions, occurs in a time-dependent manner, our study clearly shows that deamidation is an excellent marker for red blood cell aging.

Amino Acid Sequence↗
PubMed1992

[Evaluation of non-contrast-enhanced CT in blunt abdominal trauma].

We compared the findings of noncontrast-enhanced CT with those of contrast-enhanced CT in 126 patients with blunt abdominal trauma to evaluate the usefulness of noncontrast-enhanced CT. In 112 of the patients, visceral injuries were confirmed by surgery or clinical follow-up including CT. Although noncontrast-enhanced CT diagnosed all patients with 12 intestinal injuries requiring immediate surgery, contrast-enhanced CT missed two of these patients because high density hematomas on noncontrast-enhanced CT became isodense after IV administration of contrast material. However, contrast-enhanced CT was superior to noncontrast-enhanced CT in the diagnosis of hepatic and renal injuries. A case of renal artery occlusion was only visualized on contrast-enhanced CT. We conclude that both noncontrast- and contrast-enhanced CT should be performed for the CT evaluation of blunt abdominal trauma.

Abdominal Injuries↗
PubMed1992

Myocardial energetics and cardiac function of preserved rat heart.

We studied mitochondrial function in relation to ATP production and its relationship with myocardial oxygen consumption (VO2) and total mechanical energy using isolated rat hearts after 8, 12, and 24 h of hypothermic preservation. In isovolumic contraction, ventricular contractility and total mechanical energy were respectively assessed by the end-systolic elastance (Ees) and pressure-volume area (PVA). Ees significantly decreased after hypothermic ischemia, although the difference was not significant between 8 and 12 h. In contrast, VO2 measured at each left ventricular volume increased after hypothermic ischemia. PVA and VO2 were found to stay in linear correlation after prolonged hypothermic ischemia, although VO2 at null PVA and VO2 to PVA ratios significantly increased after hypothermic ischemia, especially after 12-h ischemia. Mitochondrial oxidative phosphorylation significantly decreased after hypothermic ischemia for longer than 12 h. These results indicate that mitochondrial oxidative phosphorylation was impaired due to long time hypothermic ischemia especially after 12-h ischemia. We conclude that energy uncoupling between VO2 and PVA in hypothermically preserved heart is attributable to disturbed mitochondrial oxidative phosphorylation and that 8 h is a critical point for efficient conversion of energy from VO2 into PVA in rat heart.

Animals↗
PubMed1992

DNA fragmentation and cytotoxicity by recombinant human tumor necrosis factor in L929 fibroblast cells.

Induction of cell DNA fragmentation by treatment of recombinant human Tumor Necrosis Factor alpha (rhTNF alpha) was examined by using mouse L929 cells derived from mouse fibroblast cells. The amount of DNA fragments derived from rhTNF alpha-treated cells, detected by alkaline elution technique, was smaller than that derived from X-irradiated cells. The rhTNF alpha caused the DNA fragmentation depending on its incubation time and concentration. The DNA damage caused by rhTNF alpha treatment correlated with its cytotoxicity. This result suggested that the DNA fragmentation is one of causes of cell death. The treatment with proteinase K of DNA obtained from rhTNF alpha-treated cells did not increase the amount of DNA fragmentation, which indicates that rhTNF alpha causes DNA-fragmentation but not DNA-protein cross-linking.

Animals↗
PubMed1992

Non-specific natural cytotoxic factor released from bovine peripheral blood lymphocytes.

Natural cytotoxicity against bovine leukemia cells (PC-3 cells) was found in bovine peripheral blood lymphocytes (PBL), and in non-adherent cells but not in adherent cells to nylon-wool column. Natural cytotoxic cells (NCC), which have natural cytotoxic activity, are found in T cell-rich fraction. When NCC were cocultured with PC-3 cells, natural cytotoxic factor (NCF) was released rapidly from NCC, and dose-response curve for NCF was almost linear induction. Cytotoxicity against PC-3 cells by NCC or NCF was increased with an increment of incubation period. Cytotoxicity against K562 cells, CL-1 cells, M1 cells or EL-4 cells by NCF was almost the same level as that against PC-3 cells, but that against those cell lines by NCC was not found. NCF activity in culture fluid from NCC cocultured with K562 cells or CL-1 cells was lower than that from NCC cocultured with PC-3 cells.

Animals↗
PubMed1992

[A case report of radiation osteomyelitis 9 years after irradiation for thymoma].

Radiation osteomyelitis of the sternum is rare and usually difficult to cure. A 75-year-old man, who had undergone an exploratory sternotomy for a mediastinal tumor, not resected after all, 9 years earlier and received radiation therapy successively for the histological diagnosis of malignant thymoma, was admitted to our hospital with the chief complaint of fever and pus discharge of the anterior chest wall. He also suffered from diabetes mellitus. The skin around the fistula was dark-red and atrophic due to irradiation dermatitis and the manubrium was fissured in the midline. Open drainage and two-stage operation of direct closure was tried in vain. This case was treated successfully by resection of necrosed portion of sternum and pectoral muscle flap closure.

Aged↗
PubMed1992

[A case of lung cancer in a patient with von Recklinghausen's disease].

A 57-year-old man was admitted to our hospital for further investigation of an abnormal shadow in his chest X-ray. He had cafe-au-lait spots and multiple subcutaneous neurofibromas and was diagnosed as having von Recklinghausen's disease. Bronchofiberscopy was performed, but an adequate specimen was not obtained. Therefore, percutaneous needle biopsy was performed, and the specimen showed poorly-differentiated adenocarcinoma. The left subclavian artery was deviated on aortography, therefore, neoadjuvant chemotherapy with CDDP & VDS was performed. He subsequently underwent left upper lobectomy. Pathologically, the tumor cell showed necrosis and scarring. Including this case, there have been 11 reports of von Recklinghausen's disease associated with lung cancer in the Japanese literature. Adenocarcinoma was observed in 72.9% of cases, and poorly-differentiated tumor was observed in 7 out of 8 patients with distinct tumor differentiation.

Adenocarcinoma↗
PubMed1992

Continuous monitoring of blood oxygen saturation of internal jugular vein as a useful indicator for selective cerebral perfusion during aortic arch replacement.

We continuously monitored blood oxygen saturation in the internal jugular vein during selective cerebral perfusion for aortic arch operations and evaluated its efficacy as an indicator of cerebral oxygen metabolism. The selective cerebral perfusion method was applied in 11 patients who underwent operations for aortic arch replacement. Blood oxygen saturation in the internal jugular vein was continuously monitored at the bulbus jugularis with a fiberoptic catheter during the operation. Perfusion flow of 500 ml/min was continued for 134.7 +/- 14.9 minutes under moderate hypothermia at 25 degrees C, and bilateral temporal arterial pressure was 40 to 60 mm Hg. Blood gas data were used to estimate oxygen consumption, oxygen extraction ratio, and lactate uptake in the cerebrum. No patients had postoperative cerebral complications. Cerebral oxygen consumption was 2.93 +/- 0.4 ml/min/100 gm under general anesthesia at 36 degrees C. While selective cerebral perfusion at 25 degrees C decreased consumption to 0.92 +/- 0.39 ml/min/100 gm, it fell to about 30% of its former value. Blood oxygen tension in the internal jugular vein showed no significant correlation with rectal temperature. Selective cerebral perfusion did not significantly affect cerebral lactate uptake. In contrast, blood oxygen saturation in the internal jugular vein was significantly affected by temperature and cerebral flow during selective cerebral perfusion, and blood oxygen saturation in the internal jugular vein correlated closely with cerebral oxygen extraction ratio (r = 0.91). Cerebral oxygen metabolism was thus well maintained, and continuous monitoring of blood oxygen saturation in the internal jugular vein was found to serve as a useful indicator under selective cerebral perfusion during operations for aortic arch replacement.

Adult↗
PubMed1991

[MRI of breast tumors with emphasis on histopathologic correlation].

Breast MR imaging is now expected as the third most important diagnostic modality. The author investigated relationship between signal intensity of T2 weighted images (T2WI) and various pathological findings of 51 mass lesions in 51 female patients. T2WI were not effective in differentiation between malignant and benign lesions. High signal intensity areas defined visually well correlated with pathological tissues with large water content such as necrosis, edema, cyst and dilatated ducts. There was also good correlation between low signal intensity areas and pathological tissue with less water content such as fibrosis, scar, and hyalinization. Signal intensity measured by tumor/fat ratio had no correlation with water content. It probably indicates that visually defined signal intensity is more reliable than the measured ratio. In conclusion, it is warranted to say that T2WI is a good tool for investigating secondary changes of breast tumors and helpful in diagnosis of high intensity tumors described above.

Adenocarcinoma↗
PubMed1991

2-Chlorodeoxyadenosine inhibits the repair of DNA double-strand breaks and does not inhibit the repair of DNA single-strand breaks in X-irradiated Chinese hamster V79 cells.

The exposure of log-phase Chinese hamster V79 cells to 2-chlorodeoxyadenosine (CdA) for 3 h after X irradiation enhanced the lethal effects of X-rays in a concentration-dependent manner. The enhancement of the killing efficiency of X-rays by CdA was mainly observed in the reduction of quasi-threshold doses (Dq) of the dose-response curves. When the ability of CdA to inhibit the repair of X-ray-induced double- and single-strand breaks (dsb and ssb) of DNA was investigated by neutral- and alkaline-filter elution techniques, respectively, it was observed that 90% of dsb were rejoined in the absence of CdA within 30 min after X irradiation and 15-40% of dsb rejoining was suppressed by co-incubation of the cells with 5-10 microM of CdA for 3 h after X irradiation, whereas almost 100% of ssb were rejoined within 15 min regardless of the presence or absence of CdA. From these results it was concluded that CdA interfered exclusively with the repair of DNA dsb in X-irradiated Chinese hamster V79 cells and thereby increased the lethality of X-rays.

2-Chloroadenosine↗
PubMed1991

Characterization of free radicals in gamma-irradiated polycrystalline uridine 5'-monophosphate: a study combining ESR, spin-trapping and HPLC.

Free radicals generated in gamma-irradiated polycrystalline uridine 5'-monophosphate (5'-UMP) were studied by ESR, spin-trapping and high-performance liquid chromatography (HPLC). After gamma-irradiation at 0 degree C (70kGy), poly-crystalline 5'-UMP was dissolved in an anaerobic aqueous solution of 2-methyl-2-nitrosopropane as a spin trap at room temperature. Since an ESR spectrum consisting of several components was observed immediately after irradiation, these components were separated with reverse-phase HPLC in the ion-suppression mode and again analysed by ESR spectrometry. Although HPLC ultimately gave four spin-adducts, one component that was originally present disappeared during HPLC. Spin adducts due to two types of C6 radicals were identified. One of these was thought to be formed by electron addition and subsequent protonation at the C6 position, and the other was presumed to be produced by electron addition and subsequent protonation at the O4 position. The spin adducts derived from the C5 and C5' radicals were also identified. The spin adduct that disappeared during HPLC was thought to correspond to the C4'-centred radical. Computer simulation of ESR spectra was carried out to estimate the hyperfine splitting constants.

Chromatography, High Pressure Liquid↗
PubMed1991

[Serotypes and antibiotic sensitivity of hemolytic streptococci isolated from clinical specimens in Hiroshima Prefecture, 1987-1989].

The grouping, the typing and the drug-sensibility of hemolytic streptococci isolated from the clinical specimens taken from 4 medical centers in Hiroshima Prefecture have been examined and reviewed during the past 3 years 1987-1989. The results were summarized in this report. 1. Of 1572 strains of hemolytic streptococci, 844 strains (53.7%) were group A; 539 strains (34.3%), group B; 14 strains (0.9%), group C; 82 strains (5.2%), group G; and 93 strains (5.9%), the others. We found that group A and group B were predominant, and the incidence rate of group B was higher than it used to be. 2. The prevalent types were T-4 (37.9%), T-1 (13.6%), T-12 (12.0%), and T-28 (10.7%) in group A, while Ia (26.2%), M9 (provisional type 18.4%), and III (14.5%) in group B. 3. As far as the detection data of each month is concluded, during the summer season we could hardly detect group A which peak of occurrence during the winter season. These findings were really consistent with the occurrence pattern of those patients who suffered from streptococcal infectious disease. But this occurrence pattern couldn't be found in group B. 4. In our study, the positive frequency was throat swab greater than urine greater than sputum greater than vaginal swab greater than pus greater than ear secretion in order. Group A was mainly isolated from throat swab, while group B, from several specimens including urine. 5. We found that there was a high drug-sensibility to the beta-lactam drugs in all strains except for 3 strains of group B which were resistant to CEX.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1991

Expression of arginase by mouse myeloid leukemic cell differentiation in vitro induced with tumor necrosis factor.

Induction of arginase activity in mouse myeloid leukemic M1 cells by treatment with recombinant human tumor necrosis factor (rH-TNF) or TNF-elicited mouse serum (TNS) were examined in vitro. M1 cells differentiated into macrophage-like cells by addition of rH-TNF or TNS. The differentiated cells expressed phagocytic function and did not grow anymore. Cytolytic effect of rH-TNF or TNS was not observed. The differentiation of M1 cells into phagocytic cells by the TNS treatment was more rapidly than that by the rH-TNF treatment though TNS contained 25-time less amounts of TNF indicating species specificity of TNF action on myeloid leukemic cells or TNS containing other differentiation factor(s). 3H-ornithine formation from 3H-arginine is catalyzed by arginase (EC. 3.5.3.1). The enzyme product increased in the M1 cell culture medium by the treatment with rH-TNF or TNS. The arginase activity statistically correlated with the appearance percentage of differentiated cells with phagocytic function. These results suggest that in vitro differentiation of M1 cells is accompanied by induction of arginase activity.

Animals↗