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Biomedical subjects

S Tabata

Publications and source records attributed to S Tabata.

At least 181 records · Page 10Linked to original sources
PubMed1993

High plasma concentrations of endothelin-like immunoreactivities in patients with hepatocellular carcinoma.

The plasma levels of endothelin-like immunoreactivities (ET-IR) of patients with hepatocellular carcinoma (HCC) were compared with those of patients with liver cirrhosis (LC), using a specific radioimmunoassay for endothelin-1. The mean concentration of plasma ET-IR of 21 HCC patients (30.3 +/- 8.5 pg/ml, n = 21) (means +/- SD) was markedly higher than those in LC (22.1 +/- 4.7 pg/ml, n = 16) (p < 0.01), which were also elevated compared with those in normal subjects (9.4 +/- 1.6 pg/ml, n = 91). Moreover, the level of plasma ET-IR reflected the tumor size of HCC patients, which was estimated by the ultrasonic and computed tomographic examinations. Although there was no relation to other biochemical parameters indicating liver function or tumor markers such as alpha-fetoprotein, a good positive correlation was obtained between plasma ET-IR and C-reactive protein (CRP) concentrations of HCC patients (r = 0.805, p < 0.01). We measured the tissue contents of ET-IR in HCC and its adjacent LC tissue, but failed to find any significant difference between the mean content of HCC (0.50 +/- 0.38 ng/g) and LC (0.44 +/- 0.28 ng/g). The endothelial cell damage due to cancer growth may not be responsible for the high concentrations of plasma ET-IR of HCC, because plasma thrombomodulin concentrations were not correlated with plasma ET-IR levels in HCC patients. Our study implies that the high plasma concentration of ET-IR is pathogenomonic to HCC, although the site of production is still debatable.

Aged↗
PubMed1992

Properties of yeast debranching enzyme and its specificity toward branched cyclodextrins.

Debranching enzyme was purified from Saccharomyces cerevisiae by DEAE-cellulose, omega-aminobutyl agarose and hydroxyapatite column chromatography. The activity of the eluent was monitored by the iodine-staining method which detects both the direct and indirect debranching enzymes. The elution profiles at every step showed a single peak with no shoulder. The crude and the purified enzyme preparations gave a single activity band with the same mobility on PAGE. The crude product produced 80% glucose compared to reducing sugar from glycogen-phosphorylase-limited dextrin while the partially purified and purified preparations produced 100% glucose. The activity of the purified enzyme was characterized and compared with that of the rabbit muscle enzyme by using various branched cyclodextrins as substrates. Both enzymes hydrolyzed 6-O-alpha-D-glucosyl cyclodextrins to glucose and cyclodextrins, but did not act on 6-O-alpha-maltosyl cyclomaltoheptaose. The yeast enzyme gave rise to glucose as a sole reducing sugar from 6-O-alpha-maltotriosyl cyclomaltoheptaose and 6-O-alpha-maltotetraosyl cyclomaltoheptaose, indicating that maltosyl and maltotriosyl transfers, respectively, had occurred, prior to the action of amylo-1,6-glucosidase. 6-O-alpha-D-Glucosyl cyclomaltoheptaose and 6-O-alpha-D-glucosyl cyclomalto-octaose, respectively, were better substrates than glycogen-phosphorylase-limited dextrin for the yeast and muscle enzymes. The yeast enzyme released glucose at a similar rate from 6-O-alpha-maltotriosyl cyclomaltoheptaose as from 6-O-alpha-maltotetraosyl cyclomaltoheptaose, but considerably lower rates than that from limit dextrin. The yeast debranching enzyme appears to be exclusively oligo-1,4----1,4-glucantransferase-amylo-1,6-glucosidase and does not have isoamylase.

Carbohydrate Sequence↗
PubMed1992

Osteogenesis associated with bone gla protein gene expression in diffusion chambers by bone marrow cells with demineralized bone matrix.

Diffusion chambers with rat bone marrow cells and demineralized bone matrix (DBM) were implanted subcutaneously to syngeneic 8-week-old rats and were harvested every week 3-7 weeks after implantation, and histochemical examination, determination of alkaline phosphatase activity, total calcium and phosphorus, the bone-specific vitamin K-dependent gla-containing protein (BGP) content, and detection of BGP mRNA relative to mineralization were performed. Alkaline phosphatase in diffusion chamber implants reached the highest activity at 4 weeks and then decreased. Calcium and phosphorus deposits occurred at 4 weeks after implantation and were followed by marked increases until 7 weeks, which was comparable to the accumulation of BGP. The BGP gene within the diffusion chambers began to be expressed at 5 weeks, and its expression increased markedly at 7 weeks after implantation. At 4-5 weeks after implantation, new bone adjacent to the membrane filters and cartilage toward the center of the diffusion chamber were observed histochemically. Light microscopic and immunohistologic examinations of chambers with marrow cells and DBM revealed production of mineralized matrices, typical of bone characterized by the appearance of BGP and mineralized nodules. In contrast, bone marrow cells alone did not show extensive bone formation and yielded very low values for these biochemical parameters. The present experiments demonstrate the potential of bone marrow cells and DBM to produce not only cartilage formation but also membranous bone formation associated with increasing expression of BGP mRNA during the later stages of bone formation, as well as a marked accumulation of BGP.

Alkaline Phosphatase↗
PubMed1992

Rotator cuff tears in anterior dislocation of the shoulder.

We diagnosed 16 rotator cuff tears in 109 shoulders in 104 patients with a traumatic anterior dislocation. Twelve of these were followed up for an average of 32 months. A surgical repair of the cuff was carried out in eleven and the results were satisfactory in eight (73%) regardless of a Bankart lesion. The repair of a torn cuff seems to be sufficient to stabilise the shoulder in elderly patients, even when a Bankart lesion is present and is not repaired.

Aged↗
PubMed1992

Absorptive-mediated endocytosis of an adrenocorticotropic hormone (ACTH) analogue, ebiratide, into the blood-brain barrier: studies with monolayers of primary cultured bovine brain capillary endothelial cells.

The internalization of a neuromodulatory adrenocorticotropic hormone (ACTH) analogue, [125I]ebiratide (H-Met(O2)-Glu[125I]His-Phe-D-Lys-Phe-NH(CH2)2NH2), was examined in cultured monolayers of bovine brain capillary endothelial cells (BCEC). HPLC analysis of the incubation solution showed that [125I]ebiratide was not metabolized during the incubation with BCEC. The acid-resistant binding of [125I]ebiratide to BCEC increased with time for 120 min and showed a significant dependence on temperature and medium osmolarity. Pretreatment of BCEC with dansylcadaverine or phenylarsine oxide, endocytosis inhibitors, and 2,4-dinitrophenol, a metabolic inhibitor, decreased significantly the acid-resistant binding of [125I]ebiratide. The acid-resistant binding of [125I]ebiratide was saturable in the presence of unlabeled ebiratide (100 nM-1 mM). The maximal internalization capacity (Bmax) at 30 min was 7.96 +/- 3.27 pmol/mg of protein with a half-saturation constant (Kd) of 15.9 +/- 6.4 microM. The acid-resistant binding was inhibited by basic peptides such as poly-L-lysine, protamine, histone, and ACTH but was not inhibited by poly-L-glutamic acid, insulin, or transferrin. These results confirmed that ebiratide is transported through the blood-brain barrier via an absorptive-mediated endocytosis.

Adrenocorticotropic Hormone↗
PubMed1992

In-vivo blood-brain barrier transport of a novel adrenocorticotropic hormone analogue, ebiratide, demonstrated by brain microdialysis and capillary depletion methods.

The transport of ebiratide, a novel adrenocorticotropic hormone (ACTH) analogue, [H-Met-(O2)-Glu-His-Phe-D-Lys-Phe-NH(CH2)8-NH2], through the blood-brain barrier was directly demonstrated in-vivo. [125I]Ebiratide (16.9 MBq mL-1) or [14C]sucrose (29.2 MBq mL-1) known to be restrictively transported through the blood-brain barrier was infused into the rat internal carotid artery at a flow rate of 50 microL min-1 for 10 min, and after 15 min infusion the distribution volume of each compound in the brain parenchyma was determined by the capillary depletion method. The distribution volume of [125I]ebiratide was 167.8 +/- 62.2 microL (g brain)-1, which was about seven times higher than that of [14C]sucrose (24.9 +/- 4.0 microL g brain)-1, indicating the uptake of ebiratide into brain parenchymal cells. During the infusion into the internal carotid artery, brain microdialysis was simultaneously performed to directly collect the brain interstitial fluid as the dialysate. Radioactivity was detected in the dialysate during the [125I]ebiratide infusion and HPLC analysis of the dialysate revealed that the intact ebiratide accounted for greater than or equal to 80% total radioactivity. The concentrations of [125I]ebiratide and [14C]sucrose in the brain interstitial fluid were estimated based on the relative recovery obtained in the in-vitro recovery study. The brain interstitial fluid/internal carotid arterial blood concentration ratio for [125I]ebiratide was determined to be 1.47 x 10(-2) +/- 0.17 x 10(-2) and was about eight times higher than that for [14C]sucrose (1.92 x 10(-3) +/- 0.36 x 10(-3)), indicating significant transport of ebiratide to the brain interstitial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

Changes in intracellular cAMP level and activities of adenylcyclase and phosphodiesterase during meiosis of lily microsporocytes.

In the yeasts, Saccharomyces cerevisiae and Schyzosaccharomyces pombe, reduction of intracellular cyclic adenosine monophosphate (cAMP) is known to trigger the sporulation processes by activating various meiosis specific genes. In order to ascertain whether a similar mechanism is operative in higher plants, we carried out preliminary studies on lily microsporocytes. Measurement of cAMP levels as well as the activities of adenyl cyclase and phosphodiesterase in somatic cells and different stages of meiosis, and arrest of its in protoplasts cultured under conditions of high cAMP provided direct evidence that similar phenomena occur in plant meiocytes as earlier documented in yeasts.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1992

Incomplete rotator cuff tears. Results of operative treatment.

Thirty-eight shoulders of 36 patients with incomplete rotator cuff tears surgically repaired were evaluated, with an average follow-up period of 4.9 years. The average age at operation was 52.2 years. Three types of incomplete tears were identified: superficial (12 shoulders), intratendinous (three), and deep surface tears (23). Full-thickness cuff involving the lesion was resected and repaired by side-to-side suture (13 shoulders), side-to-bone suture (eight), fascial patch grafting (16), or side-to-bone suture with fascial patch grafting (one). The overall results were satisfactory in 31 shoulders (82%). The results were not affected by the tear types, operative methods, or follow-up period. The patients with poor results were associated with major complications other than rotator cuff tears or with insufficient resection of the damaged cuff. When the full-thickness cuff involving the lesion is completely resected and repaired, long-term satisfactory results can be anticipated in a high percentage of patients regardless of tear types.

Adolescent↗
PubMed1992

Conservative treatment of rotator cuff tears.

Among 124 shoulders in 114 patients with complete rotator cuff tears who had been treated conservatively from 1980 until 1989, 62 shoulders in 54 patients were observed to identify the findings on initial examinations and correlate them with the final results. The follow-up period averaged 3.4 years. According to modified criteria of Wolfgang, 51 shoulders in 45 patients (82%) rates satisfactory (excellent or good). The overall scores of pain, motion, and function improved significantly. The results were less satisfactory in patients observed more than six years. The patients with satisfactory results (Group 1) and unsatisfactory results (Group 2) among those observed more than five years were compared. In Group 1, the scores of pain, motion, and strength improved significantly at follow-up examinations, whereas those of function did not. In Group 2, no improvement was recognized in any categories. The only significant differences in the initial findings between the two groups were the active abduction angle and the abduction strength: the patients in Group 1 retained a good range of motion and strength, whereas those with unsatisfactory results had a limited range and muscle weakness on first examinations. Conservative treatment affords satisfactory results when it is given to the patients with well-preserved motion and strength, although in some cases function may deteriorate with time.

Adult↗
PubMed1991

Evidence for increased in vitro recombination with insertion of human hepatitis B virus DNA.

Chromosomal translocation, deletion, and inversion/duplication directly linked to hepatitis B virus (HBV) DNA integration occur frequently in host DNA of human hepatocellular carcinomas. To test the possible recombinogenic effect of HBV DNA, we have utilized an in vitro recombination assay. Fragments containing the region spanning DR1, which is believed to be the origin of viral replication and a preferred site in the viral genome for integration, increased the recombination events reproducibly in the presence of extracts from actively dividing cells (e.g., hepatocellular carcinoma) but not resting cells (e.g., normal liver). Moreover, in these extracts we have found a protein(s) that specifically binds to these HBV DNA fragments. These results support the notion that in some instances integrated HBV DNAs cause further genomic instability, possibly involving specific cellular protein(s). The fact that extracts from nondividing, normal liver did not increase recombination events suggests that genomic instability depends upon active cellular growth, a feature more commonly found subsequent to HBV-induced hepatocellular injury than in healthy liver. Our results offer an explanation for the high incidence of liver cancer that accompanies chronic hepatitis and add HBV to the list of agents that can cause genetic recombination.

Animals↗
PubMed1991

HIV-EP2, a new member of the gene family encoding the human immunodeficiency virus type 1 enhancer-binding protein. Comparison with HIV-EP1/PRDII-BF1/MBP-1.

At least two different types of proteins, NF-kappa B/KBF1 and HIV-EP1/PRDII-BF1/MBP-1, which are members of a family of rel oncoproteins and metal-finger proteins, respectively, bind to the human immunodeficiency virus type (HIV-1) enhancer. As a new member of a HIV-EP1 family that is expressed at a high level in T cells, we have isolated cDNA clones of HIV-EP2 by cross-hybridization with HIV-EP1 cDNA. HIV-EP2 protein consists of 1,833 amino acids and has a molecular weight of 211,000. HIV-EP2 protein is highly homologous with HIV-EP1/PRDII-BF1/MBP-1 in three regions. These three regions contain the potential nuclear localization signal followed by a Ser/Thr-rich region, the DNA-binding domain consisting of a metal-finger structure, and a cluster of acidic amino acids. The DNA-binding property of HIV-EP2 was similar to that of HIV-EP1. Northern blot analysis of HIV-EP2 mRNA indicated relatively high expression in the T cell line Molt-4 and in some tumor cell lines. Furthermore, like HIV-EP1, expression of HIV-EP2 mRNA was greatly induced by mitogen and phorbol ester treatment of Jurkat T cells, suggesting that HIV-EP2 acts in HIV production from latently infected T cells.

Amino Acid Sequence↗
PubMed1991

Determination of felodipine and its metabolites in plasma using capillary gas chromatography with electron-capture detection and their identification by gas chromatography-mass spectrometry.

A novel method for the determination of felodipine and its metabolites in plasma by capillary gas chromatography (GC) with electron capture detection was developed. Felodipine and its oxidized metabolite were assayed by capillary GC after solid-phase extraction with the aid of a cool on-column injection technique. Acid metabolites, methyl monoacid and ethyl monoacid and diacid, were extracted with diethyl ether and propylated with 1-n-propyl-3-p-tolyltriazene before being submitted to capillary GC. These methods were very sensitive and useful for the pharmacokinetic study of felodipine. Felodipine and its metabolites were identified by GC-mass spectrometry. The mass spectral patterns of the peaks of extracts from human plasma samples after oral administration of felodipine were in good agreement with those of reference compounds.

Chromatography, Gas↗
PubMed1991

Transport mechanism of a new behaviorally highly potent adrenocorticotropic hormone (ACTH) analog, ebiratide, through the blood-brain barrier.

The binding and internalization of a novel adrenocorticotropic hormone (ACTH) analog having a potent neuromodulating effect, ebiratide (H-Met(O2)-Glu-His-Phe-D-Lys-Phe-NH(CH2)8NH2), by isolated bovine brain capillaries, were examined. Metabolism of [5-125I-His]ebiratide occurred during a 30-min incubation with bovine brain capillaries at 37 degrees C. In the presence of 20 mM EDTA, added to inhibit this metabolism, the medium, after 30 min of incubation, contained 82.3 +/- 0.5% of the unchanged ebiratide. The total binding and acid-resistant binding of [125I]ebiratide increased with time and reached an equilibrium at about 15 min. The total binding and acid-resistant binding at 30 min (as the cell/medium ratios corrected with [14C]sucrose) were 13.07 +/- 0.86 and 5.00 +/- 0.18 microliters/mg of protein, respectively. The acid-resistant binding showed significant dependence on temperature and medium osmolarity. The [125I]ebiratide binding was significantly inhibited by dansylcadaverine, an endocytosis inhibitor. The saturable acid-resistant binding was obtained by the addition of unlabeled ebiratide (100 nM-5 mM), and the maximal internalization capacity (Bmax) at 30 min was 144.2 pmol/mg of protein, with the half-saturation constant (KD) of 62.1 microM. The nonsaturable acid-resistant binding [cell/medium ratio in the presence of the unlabeled compound (1 mM or more)] was 2.2 microliters/mg of protein. The acid-resistant binding was significantly inhibited by human ACTH, poly-L-lysine, protamine and E-2078, a basic peptide, but was not inhibited by poly-L-glutamate, insulin or transferrin. These results demonstrate that ebiratide is transported through the blood-brain barrier via a basic peptide-specific absorptive-mediated endocytosis.

Adrenocorticotropic Hormone↗
PubMed1991

[Chemotherapy of prostatic cancer].

CDDP combined chemotherapy was performed in 55 cases out of 229 prostatic cancer patients who were treated in Nara Medical University and Nara Prefectural Nara Hospital between January 1979 and August 1989. The previously untreated 33 patients received chemotherapy with anti-androgen treatment as an initial treatment, as well as 7 cases of unresponsive to antiandrogen treatment, 14 relapsing cases and one case with recurrence after total prostatectomy. The major regimens of chemotherapy were cis-diammine dichloroplatinum (CDDP) alone in 16 cases, PVB regimen (bleomycin or peplomycin + vincristine + CDDP) in 19 cases, and CAP regimen (cyclophosphamide + adriamycin + CDDP) in 16 cases. Complete response was not achieved or partial response was observed in 20 cases (34%), no change was seen in 20 cases (34%), and progression was seen in 19 cases (32%). Among each evaluable lesion, effects (CR + PR) were observed in 40% in the prostate, in 18% in the bone lesions, in 44% in the soft tissue lesions, and in 42% in the prostatic tumor marker. The 7-year survival rate of the chemotherapy group (35.6%) was better than that of the antiandrogen treatment group (26.6%) in stage D patients, but was not significant statistically When evaluated by the regimen, a partial response was observed in 56% of CDDP alone, in 21% of PVB regimen, and in 38% of the CAP regimen. However, there was no significant difference in survival rate among the regimens. As an adverse effect, myelosuppression and renal toxicity seemed to be dose limiting factors of CDDP combined chemotherapy for advanced prostatic cancer patients.

Aged↗
PubMed1991

Tumor thrombus and microvascular invasion as prognostic factors in renal cell carcinoma.

The significance of two types of vascular invasion (macroscopic tumor thrombus into the renal vein or vena cava inferior and microvascular invasion) as prognostic factors in renal cell carcinoma is analyzed in 121 patients treated at the Department of Urology, Nara Medical University. The data indicate there to be close correlations between tumor thrombus, microvascular invasion and distant metastasis. In patients with tumor thrombus, however, the prognosis is not as poor when surgical removal of the tumor thrombus is successfully performed as when it is not. In contrast, the prognosis of patients with positive microvascular invasion is significantly worse than that of those with a negative finding. Microvascular invasion appears to be a significant prognostic factor in renal cell carcinoma in addition to well-known factors such as tumor stage, tumor grade, tumor thrombus and distant metastasis. To detect microvascular invasion, the histological examination should be extended to give as much detail as possible.

Adult↗
PubMed1990

ATP-independent strand transfer protein from murine spermatocytes, spermatids, and spermatozoa.

A protein-catalyzing D-loop formation is present in murine spermatocytes, spermatids, and spermatozoa, but is not found in somatic tissue or in premeiotic cells of the germline. Unlike the Escherichia coli RecA protein and the meiotic rec protein (m-rec) previously described, D-loop formation by this protein (referred to as "mAi-rec") does not require ATP. The meiotic profile of mAi-rec activity is only partly similar to that of m-rec. Like m-rec, it rises steeply during early prophase and reaches a peak at pachytene. Unlike m-rec, its activity remains high during the postmeiotic phase of spermatid development and is prominent in immunochemically stained spermatozoa. A polyclonal antibody to E. coli RecA reacts with mAi-rec and inhibits its activity. No such reaction occurs with m-rec protein. The extent of sequence homology between E. coli RecA and murine mAi-rec is highly limited; none of the several monoclonal antibodies tested reacted with mAi-rec.

Adenosine Triphosphate↗