Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 19 recordsLinked to original sources

PubMed1999

Preoperative transcatheter arterial chemoembolization and prognosis of patients with hepatocellular carcinomas: retrospective analysis of 120 cases.

To clarify whether preoperative transcatheter arterial chemoembolization (TAE) improves the prognosis of patients with hepatocellular carcinoma (HCC) after surgery, 120 patients who had undergone hepatectomy for HCC from 1988 to 1994 and satisfied the criteria of stages II and III were enrolled in this study. Forty-four patients underwent preoperative TAE (group A) and 76 patients did not (group B). No significant differences in the outcomes were observed between these two groups. To rectify the comparison, patients with tumors 2 to 8 cm were assigned to groups A1 (n = 24) and B1 (n = 57), and those with tumors > 8 cm were assigned to groups A2 (n = 20) and B2 (n = 19), respectively. Although no significant differences in survival between groups A1 and B1 were found, group A2 presented superior 1-, 2-, and 3-year tumor-free survival rates of 80%, 55%, and 32% and 1-, 3-, and 5-year cumulative survival rates of 90%, 53%, and 42%. These figures are in comparison with the tumor-free survival rates of 50%, 22%, and 11% (p = 0.06), and the cumulative survival rates of 72%, 33%, and 11% (p = 0.01) during the same periods for group B2, respectively. The Cox regression model revealed that for patients with tumors > 8 cm, the relative risk of preoperative TAE for overall survival was 0.38 (p = 0.017), indicating that preoperative TAE might benefit patients with tumors > 8 cm but not those with tumors 2 to 8 cm.

Adult↗

PubMed1999

Enzyme-linked immunosorbent assay detection of prostate-specific antigen messenger ribonucleic acid in prostate cancer.

OBJECTIVES: To develop a rapid, sensitive, reverse transcriptase-polymerase chain reaction (RT-PCR) prostate-specific antigen (PSA) messenger ribonucleic acid (mRNA) detection method by applying colorimetric enzyme-linked immunosorbent assay (ELISA). METHODS: Total RNA was extracted from 16 urogenital cancer cells (including PSA-producing LNCaP cells) from pelvic and inguinal lymph node aspiration biopsy samples from patients with prostate, bladder, and penile cancer, as well as from blood samples of 500 patients with urogenital cancer. We used rTth polymerase for RT and PCR. The RNA target was amplified by RT-PCR with dinitrophenyl-labeled primer. The PCR product was denatured and hybridized on a PSA-specific probe-coated microwell plate. RESULTS: In 1 6 cancer cell lines, only LNCaP cells expressed especially high PSA mRNA values, with an optical density (OD) greater than 3. In other cell lines, two testicular cells had relatively high ODs, 1.909 and 0.987, respectively. A high PSA mRNA value was obtained by fine needle aspiration from pelvic lymph node specimens of cytologically positive lymph nodes from patients with prostate cancer but not from patients with cytologically proved bladder or penile cancer. Sensitivity and specificity of fine needle aspiration samples were 70% and 100%, respectively. Blood tests obtained from patients with prostate cancer demonstrated high PSA mRNA values. CONCLUSIONS: The PSA mRNA RT-PCR ELISA method provides a sensitive photometric enzyme immunoassay for the detection of PSA mRNA, using nonradioactive techniques.

Enzyme-Linked Immunosorbent Assay↗

PubMed1999

Changes of angiogenesis and tumor cell apoptosis during colorectal carcinogenesis.

Activation of the angiogenic process occurs during tumorigenesis, as does disturbance of cell proliferation and apoptosis. Seeking a potential correlation, we investigated tumor cell apoptosis, proliferation, and angiogenesis in the adenoma-carcinoma sequence of colorectal carcinogenesis using an in situ apoptosis detection kit and MIB-1 and anti-CD34 antibodies in 27 adenomas with low dysplasia, 17 adenomas with high dysplasia, and 26 carcinomas in adenoma, as well as assessed p53 and bcl-2 expressions. The results showed that the potential for apoptosis was augmented, paralleling the increment of proliferation, in adenomas with low dysplasia but diminished when adenomas progressed from low dysplasia to high dysplasia and cancer. A gradual increment of microvessel density was observed during the progression with an increase during transition from low dysplasia to high dysplasia and cancer. Correlation coefficient test showed an inverse correlation between apoptotic index and microvessel density when all of the lesions were taken into account. No apparent impact of aberrant p53 on angiogenesis or bcl-2 on apoptosis was observed in this study. These results suggest that the angiogenesis initiates during transition from low dysplasia to high dysplasia and cancer, which may, in turn, contribute to the reduction of tumor cell apoptosis during colorectal carcinogenesis.

Adenocarcinoma↗

PubMed1998

Production of human compatible high mannose-type (Man5GlcNAc2) sugar chains in Saccharomyces cerevisiae.

A yeast mutant capable of producing Man5GlcNAc2 human compatible sugar chains on glycoproteins was constructed. An expression vector for alpha-1,2-mannosidase with the "HDEL" endoplasmic reticulum retention/retrieval tag was designed and expressed in Saccharomyces cerevisiae. An in vitro alpha-1,2-mannosidase assay and Western blot analysis showed that it was successfully localized in the endoplasmic reticulum. A triple mutant yeast lacking three glycosyltransferase activities was then transformed with an alpha-1, 2-mannosidase expression vector. The oligosaccharide structures of carboxypeptidase Y as well as cell surface glycoproteins were analyzed, and the recombinant yeast was shown to produce a series of high mannose-type sugar chains including Man5GlcNAc2. This is the first report of a recombinant S. cerevisiae able to produce Man5GlcNAc2-oligosaccharides, the intermediate for hybrid-type and complex-type sugar chains.

Amino Acid Sequence↗

PubMed1998

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression correlated with tumor angiogenesis and macrophage infiltration in colorectal cancer.

To clarify whether platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) expression in both tumor cells and stromal cells has independent or synergistic effects on tumor angiogenesis and progression and to explore a possible regulator for PD-ECGF/TP expression, immunohistochemical staining was conducted on 148 specimens of colorectal cancer. The microvessel count was significantly correlated with the extent of PD-ECGF/TP expression. Macrophage infiltration in tumors with positive TP was significantly higher than in tumors with negative TP (P < 0.001). The Cox model showed that PD-ECGF/TP expression was an independent prognostic factor, although the microvessel count had a stronger value in determining the patient prognosis.

Adenocarcinoma↗

PubMed1998

In vivo observations of the intramural arterioles and venules in beating canine hearts.

1. To evaluate the effects of cardiac contraction on intramyocardial (midwall) microvessels, we measured the phasic diameter change of left ventricular intramural arterioles and venules using a novel needle-probe videomicroscope with a CCD camera and compared it with the diameter change in subepicardial and subendocardial vessels. 2. The phasic diameter of the intramural arterioles decreased from 130 +/- 79 ìm in end-diastole to 118 +/- 72 micron (mean +/- S.D.) in end-systole by cardiac contraction (10 +/- 6 %, P < 0.001, n = 21). 3. The phasic diameter in the intramural venules was almost unchanged from end-diastole to end-systole (85 +/- 44 vs. 86 +/- 42 micron, respectively, 2 +/- 6 %, n. s., n = 14). 4. Compared with intramural vessels, the diameters of subendocardial arterioles and venules decreased by a similar extent (arterioles: 10 +/- 8 %, P < 0. 001; venules: 12 +/- 10 %, P < 0.001) from end-diastole to end-systole, respectively, whereas the diameter of the subepicardial arterioles changed little during the cardiac cycle, and subepicardial venule diameter increased by 9 +/- 8 % (P < 0.01) from end-diastole to end-systole. These findings are consistent with our previous report. 5. We suggest that the almost uniform distribution of the cardiac contractility effect and arteriolar transmural pressure between the subendocardium and the midmyocardium, which together constitute the systolic vascular compressive force, accounts for the similarity in the arteriolar diameter changes in both myocardial layers. The smaller intravascular pressure drop from deep to superficial myocardium relative to the larger intramyocardial pressure drop explains the difference in the phasic venular diameter changes across the myocardium.

Animals↗

PubMed1998

Alternatively spliced forms of cyclin D1 modulate entry into the cell cycle in an inverse manner.

Alternative splicing of cyclin D1 gene mRNA has recently been demonstrated. The novel transcript shows no splicing at the downstream exon 4 boundary and encodes a protein with an altered carboxyl-terminal domain that is a cyclin D1 variant; exon 5 is not included in the coding sequence which terminates downstream of exon 4. We here produced cells that exogenously express each form of cyclin D1 and analysed their cell cycle regulation. We found that (1) alternative splicing forms of cyclin D1 modulated entry into the cell cycle in an inverse manner; (2) both splicing forms suppressed cell growth; and (3) cells overexpressing form [a] were inhibited from entry into and completion of the S phase, although form [b]-expressing cells showed no reduction of G1- to S transition. We also found that overexpression of either cyclin D1 form upregulated Rb gene products, suggesting that this upregulation may be one of the causes of growth suppression in cyclin D1 overexpressing cells.

Alternative Splicing↗

PubMed1998

Relationship between flushing pressure and nitric oxide production in preserved lungs.

BACKGROUND: Nitric oxide (NO) is considered to be one of the endogenous inhibitory factors of ischemic reperfusion injury. In this study, the NO-producing ability of the preserved lung, flushed at various pulmonary artery pressures (flushing pressure), was studied during reperfusion using an ex vivo rabbit lung perfusion model. METHODS: The lungs were flushed with 200 ml of preservation solution with flushing pressures adjusted to 15, 15, 20, and 25 mmHg for groups 1, 2, 3, and 4, respectively (n=5 in each group). In the control group (group 1), the heart-lung block was harvested after flushing and the lungs were assessed without preservation. In the other groups, the harvested blocks were preserved at 8 degrees C for 24 hr and reperfused with homologous blood for pulmonary functional assessment. Pulmonary function was assessed by measuring mean airway pressure, mean pulmonary arterial pressure, partial oxygen tension of pulmonary venous effluent blood, and pulmonary wet-dry weight ratio. The sequential changes in the concentration of NO-related substances (NO-RS) in the serum of reperfused blood were also measured by chemiluminescence. RESULTS: During reperfusion, biphasic increases in NO-RS were observed in all groups. In groups 3 and 4, the increases in NO-RS were significantly lower than those of groups 1 and 2, and pulmonary function deteriorated. CONCLUSION: These data suggest that in order to maintain the endogenous NO-producing ability of preserved lung, the flushing pressure must be less than 20 mmHg.

Animals↗

PubMed1998

Upregulation of NMDA receptor subunit proteins in the cerebral cortex during diazepam withdrawal.

The present study investigated the changes in NMDA receptor subunit proteins in diazepam-withdrawn rat cerebral cortex, using Western blotting analysis. The protein levels of the NR1 and NR2B, but not NR2A, subunits were significantly increased in diazepam-withdrawn rats compared to those in control rats. Therefore, an increase in the NR1 and NR2B subunit proteins may be responsible for both the previously observed upregulation of [3H]dizocilpine binding in the cerebral cortex and the appearance of diazepam withdrawal signs.

Animals↗

PubMed1998

Selective antitumor activity of MKT-077, a delocalized lipophilic cation, on normal cells and cancer cells in vitro.

BACKGROUND AND OBJECTIVES: 1-Ethyl-2-¿[3-ethyl-5-(3-methylbenzothiazolin-2-yliden)]-4-+ ++oxothiazolidin-2-ylidenemethyl¿pyridium chloride (MKT-077, formerly known as FJ776), a delocalized lipophilic cation, is known to accumulate in the mitochondria, according to the negative potential inside the mitochondria, and exert its cytotoxicity. METHODS: The single-cell suspensions of human cancer cell lines, human spleen cells, and fresh cancer specimens obtained from patients with gastric carcinoma were used for the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. RESULTS: The antitumor activity of MKT-077 was dose and concentration related, and 50% inhibitory concentrations (IC50) ranged from 1.7 to 14.3 microg/ml, with a mean +/- standard deviation (SD) of 8.4 +/- 4.6 microg/ml. The IC50 of fresh surgical spleen-cell specimens ranged from 0.34 microg/ml to >100 microg/ml in a 48 h incubation, with a mean +/- SD of 66.5 +/- 37.7 microg/ml. When the antitumor activity of MKT-077 was compared between gastric cancer cells and spleen cells obtained from the same patient, the concentration-dependent antitumor activity of this agent was obvious in the cancer cells, while no significant cytotoxicity was observed in the spleen cells. The fresh surgical specimens of gastric cancer showed higher sensitivity to MKT-077 than did spleen cells at a concentration of 30 microg/ml, with a statistically significant difference at P < 0.05. CONCLUSIONS: The selective antitumor activity of MKT-077 was confirmed using fresh surgical specimens and warrants further investigation.

Antineoplastic Agents↗

PubMed1998

[Removal of retained transvenous pacemaker electrodes under cardiopulmonary bypass].

A case of breakage and removal of a retained transvenous pacemaker electrode is described. A 22-year-old woman with complete A-V block underwent implantation of a transvenous pacemaker system on the left anterior chest wall in 1989. Three years later, a new generator was implanted on the right chest wall because of local infection of the pacemaker pockets. The old electrodes could not be removed and were left in place. Beginning in 1995, the patient complained of anterior chest pain. A chest roentgenogram revealed that one of the pacemaker electrodes had broken at the right costoclavicular ligament and a fragment was floating in the superior vena vava. The retained electrodes were removed under tot cardiopulmonary bypass. These electrodes had become firmly encased with fibrous tissue within the right ventricle and atrium, but they were easily removed under direct vision duting complete cardiac arrest. The postoperative course was uneventful and the patients had no further complaint.

Adult↗

PubMed1998

Effects of depletion of leukocytes and platelets on cardiac dysfunction after cardiopulmonary bypass.

BACKGROUND: This study examined the effects of the depletion of leukocytes and platelets from circulated blood on cardiac function after cardiopulmonary bypass in 37 patients who underwent coronary artery bypass grafting or aortic valve replacement. METHODS: Leukocytes and platelets were removed continuously using a blood cell separator, beginning immediately after the start of the operation and ending 1 hour after the release of the aortic cross-clamp in 19 patients (LPD group), but not in the remaining 18 patients (control group). Blood cell counts and levels of thromboxane B2, 6-keto-prostaglandin F1alpha, leukocyte elastase, complements C3a and C4a, thrombin-antithrombin III complex, and D-dimer were determined periodically during and after the operation. The cardiac index, the difference between the central and peripheral core temperatures, and the doses of catecholamines and vasodilators required to support the circulation in the early postoperative period also were assessed. RESULTS: Leukocyte and platelet counts and levels of leukocyte elastase, thromboxane B2, thromboxane2/6-ketoprostaglandin F1alpha, thrombin-antithrombin III complex, and D-dimer were significantly lower in the LPD group than in the control group before and after the release of the aortic cross-clamp and during the perioperative period. There were no significant differences in the levels of 6-keto-prostaglandin F1alpha or complements C3a and C4a between the two groups. The catecholamine dose was significantly lower in the LPD group than in the control group (1.1 +/- 2.5 versus 5.0 +/- 5.2 mg/kg, respectively). Fewer patients required the use of nitroprusside as a vasodilator in the LPD group than in the control group (1/19 versus 12/18, respectively). CONCLUSIONS: The depletion of leukocytes and platelets using a blood cell separator prevents the deterioration of cardiac function after cardiac operations using cardiopulmonary bypass.

6-Ketoprostaglandin F1 alpha↗

PubMed1998

Tumor angiogenesis as a prognostic marker in operable non-small cell lung cancer.

BACKGROUND: Recent evidence suggests that tumor angiogenesis is associated with patient outcome in a number of malignancies. However, little is known about the significance of tumor microvessel density as evaluated by an anti-CD34 antibody in patients with lung cancer. METHODS: Tumor tissues were obtained from 101 patients with operable non-small cell lung cancers. Immunohistochemical detection of tumor-associated microvessels was performed using anti-CD34 antibodies directed against endothelial markers. Average counts of the three most vascular areas on a X200 field were recorded. RESULTS: Staining for CD34 was easy to interpret because of specific and minimal background staining. The Kaplan-Meier method showed a statistically significant difference between the microvessel count and overall survival. The microvessel count was identified as the only significant and independent prognostic marker. In both univariate and multivariate analyses, the microvessel count was significantly related to the development of hematogenous metastasis but failed to associate with the development of nodal metastasis. CONCLUSIONS: Tumor vascularity is an independent prognostic factor and important for the development of hematogenous metastasis.

Adult↗

PubMed1998

Prolongation of total permissible circulatory arrest duration by deep hypothermic intermittent circulatory arrest.

OBJECTIVE: We determined whether the duration of permissible circulatory arrest could be prolonged by deep hypothermic intermittent circulatory arrest. METHODS: Twenty-five beagles were cooled on bypass to 18 degrees C to initiate deep hypothermia that was maintained for 3 hours. Five protocols were then studied: group 1, uninterrupted bypass during hypothermia; group 2, arrest for 40 minutes during hypothermia; group 3, arrest for 60 minutes during hypothermia; group 4, arrest for 80 minutes during hypothermia; and group 5, intermittent circulatory arrest, consisting of six cycles of 20 minutes of arrest followed by 10 minutes of systemic recirculation during hypothermia (total, 120 minutes of arrest). The oxyhemoglobin concentration in the brain was measured with near infrared spectrophotometry. RESULTS: In groups 2, 3, and 4, the oxyhemoglobin concentration in the brain decreased continuously after arrest, finally reaching a plateau after 24.9 +/- 1.2 minutes. This finding suggested that the available cerebral oxyhemoglobin was depleted. In contrast, the available cerebral oxyhemoglobin was not depleted during hypothermic intermittent arrest in group 5. The mitochondrial respiratory control index was significantly lower in group 4 than in the other groups (p < 0.05). However, there were no significant differences in the respiratory control index for groups 1, 2, 3, and 5. Moreover, the formation of brain edema was significantly lower in group 5 than in the other groups (p < 0.05). CONCLUSIONS: These results indicate that deep hypothermic intermittent arrest can increase the duration of total permissible circulatory arrest and will be a useful modality when prolonged arrest is anticipated.

Animals↗

PubMed1998

Enhanced colonic and rectal absorption of insulin using a multiple emulsion containing eicosapentaenoic acid and docosahexaenoic acid.

The aim of this study was to test the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on insulin absorption from rat intestinal loops in situ, using a water-in-oil-in-water (W/O/W) multiple emulsion. The enhancement effect of these long-chain polyunsaturated fatty acids was compared with that of free fatty acids having a C18 alkyl chain. The emulsion (insulin dose, 50 units/kg) was administered directly into the colonic and rectal loops. Both EPA and DHA strongly enhanced insulin absorption and induced hypoglycemia after colonic and rectal dosing. Comparing the pharmacological availability, the order of effectiveness with respect to the enhanced absorption of insulin was DHA >/= EPA > C18 unsaturated fatty acids >> C18 saturated fatty acid at both sites. DHA showed greater effects upon rectal dosing than upon colonic dosing. Histological studies revealed that the emulsion incorporating DHA did not induce gross morphological changes in the structure of the intestinal mucosa. Our results indicate that a W/O/W multiple emulsion incorporating DHA is a possible means of facilitating the intestinal absorption of insulin without inducing any serious damage to the epithelial cells.

Animals↗

PubMed1998

Deep hypothermic intermittent circulatory arrest--an adjunct technique for operations on aneurysms involving the aortic arch.

Aneurysms involving the aortic arch were repaired in 12 patients using a technique known as deep hypothermic intermittent circulatory arrest (DHICA). This technique consists of repeated cycles of 20 min of circulatory arrest and 10 min of cerebral and systemic reperfusion. Aneurysms were of the following types: 2 true atherosclerotic aneurysm, 8 aortic dissections, and 2 traumatic aneurysm. There were 2 operative deaths caused by coagulopathy as a result of hepatic failure and difficulty with left ventricular venting. The frequency of circulatory arrest ranged from 2 to 5 cycles, and total circulatory arrest ranged from 20 to 71 min (mean 43.6 min). The lowest tympanic temperature ranged from 17.7 to 19.2 degrees C. No permanent cerebral complications occurred in 10 patients. We believe that this adjunct technique offers excellent results in the surgical treatment of aneurysms involving the aortic arch.

Adult↗

PubMed1998

[Molecular mechanisms of the hyperresponsiveness of airway smooth muscle in bronchial asthma].

Nonspecific airway hyperresponsiveness (AHR) is a common feature of allergic bronchial asthmatics, but the underlying mechanisms of AHR have yet to be elucidated. The importance of AHR in the pathogenesis of asthma has been suggested by its relevance to the severity of this disease. There is thus a need to understand the underlying mechanisms of AHR for the sake of asthma therapy. In allergic asthmatics, airway smooth muscles (ASMs) obtained from in vivo hyperresponsive patients have in vitro hyperresponsiveness to cholinergic agonists. It is therefore possible that the mechanisms responsible for the AHR exist, at least in part, on the ASM site. Although ASM is known to contract in response to acetylcholine via muscarinic M3 receptors and this contractile response is augmented during AHR, no alteration in muscarinic receptor density in ASM has been demonstrated in various AHR models. It is thus likely that augmented intracellular signaling might be a possible reason for the AHR. In fact, recent investigations demonstrated increases in the levels of GTP binding protein, Ca2+ mobilization and inositol 1,4,5-trisphosphate generation and so on in hyperresponsive ASM.

Animals↗

PubMed1998

Legionnaires' disease diagnosed by bronchoalveolar lavage.

A 51-year-old woman who had been on steroid therapy for systemic lupus erythematosus (SLE) developed a high fever 3 days after visiting a hot spring resort. Chest X-ray films revealed an interstitial, pneumonia-like shadow in the left lung field, which increased rapidly with a worsening of her symptoms. She died of multiple organ failure one week after the onset of the pneumonia. Although the serum antibody titer was negative, Legionella pneumophila was recovered from her bronchoalveolar lavage (BAL) fluid. BAL seems to be a useful method to diagnose Legionnaires' disease.

Antibodies, Bacterial↗