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Biomedical subjects

N Hirata

Publications and source records attributed to N Hirata.

152 records · Page 9Linked to original sources

Endoscopic ultrasonography in the assessment of colonic wall invasion by adjacent diseases.

For assessing the direct invasion of the colonic wall by pelvic or abdominal tumors, endoscopic ultrasonography was performed prospectively in patients who were suspected of having colonic wall invasion by barium enema. Three patients with ovarian cancer, two with endometriosis, and one with pancreatic cancer were included in this study. Preoperative endoscopic ultrasonography (EUS) revealed the relationship between the tumor and the colon in all cases. A surgical procedure was performed in all patients: resection of the tumor and a portion of the invaded colon (4) and removal of the tumor (only adhesion) (2). A correct preoperative diagnosis of the depth of tumor invasion was obtained in five of the six (83%) cases. In patients with pelvic or abdominal tumors, preoperative EUS may be useful for evaluating the presence and the degree of invasion of the colonic wall by the tumor.

Abdominal Neoplasms↗

Studies on the synthesis of sesquiterpene lactones, 12. Synthesis of (+)-colartin, (+)-arbusculin A, and their C-4 epimers and their biological activities.

Colartin [9] and arbusculin A [11] have been synthesized from alpha-santonin [1] in 14.5% (11 steps) and 9.3% (13 steps) overall yields, respectively. Arbusculin A [11] and compounds 20, 21, and 22, which were derived from intermediate 2, showed significant cell growth inhibitory activity against murine lymphocytic leukemia (P-388) in vitro. Plant growth regulating activity of 11 and its synthetic intermediates 4, 5, 8, and 9 was also studied.

Animals↗

Nitric oxide gas infusion to the oxygenator enhances the biocompatibility of heparin coated extracorporeal bypass circuits.

Heparin coated bypass circuits have been reported to improve the biocompatibility of extracorporeal circulation, although it is still insufficient and improvable. Nitric oxide (NO) is known to inhibit platelet activation and inflammatory reactions. In this study, the authors evaluated exogenous NO infusion in enhancing the effect of a heparin coated bypass circuit on the biocompatibility of an extracorporeal circuit, especially in view of the attenuation of the inflammatory response. A miniature closed bypass circuit, including an oxygenator (BioActive surface; Carmeda, Stockholm, Sweden) was primed with fresh human heparinized blood and perfused with a centrifugal pump. Either pure N2 gas (control group: n = 7) or NO gas (NO group [100 ppm in N2]: n = 7) was infused to the oxygenator. NO metabolites (nitrite and nitrate), platelet count, thrombin-antithrombin III complex (TAT), alpha2-plasmin-plasminogen inhibitor complex (PIC), beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), serotonin, complement 3 activation products (C3a), granulocyte elastase, and bradykinin were measured at 0, 30, 60, 120, and 180 min after starting perfusion. At every sampling point, platelet counts were significantly higher, and TAT, beta-TG, and bradykinin were lower in the NO group than in the control group. PF4, C3a, and granulocyte elastase were significantly lower in the NO group at 60, 120, and 180 min. These results suggest that NO gas infusion to the oxygenator enhances the biocompatibility of heparin coated extracorporeal circuits.

Biocompatible Materials↗

Predictive value of preoperative serum cholinesterase concentration in patients with liver dysfunction undergoing cardiac surgery.

OBJECTIVE: There are an increasing number of patients with severe liver dysfunction subjected to open heart surgery. This retrospective study was designed to assess operative results and clarify the degree of liver injury in patients with liver dysfunction undergoing open heart surgery. In addition, determinants influencing their prognosis were assessed. METHODS: In a 9-year period from 1988 to 1996, we operated on 31 patients with posthepatitis liver dysfunction and 16 with chronic passive congestion of the liver. This group was 2.3% and 1.6% of the 1368 patients undergoing cardiac surgery in the same period. We compared several perioperative factors between survivors and nonsurvivors to determine risk factors affecting mortality. RESULTS: In the group with posthepatitis liver dysfunction, the postoperative course of 5 patients among 31 (16.1%) was poor. Serum cholinesterase concentration was lower only in the nonsurvivor group (nonsurvivor vs survivor: 1979+/-949 vs 3515+/-1424 IU/I, p < 0.05). All patients with cholinesterase < 2000 IU/L died. The duration of CPB (212+/-53 vs 150+/-54 minutes, p < 0.03) and ACC time (151+/-38 vs 96+/-40 minutes, p < 0.02) was longer in the nonsurvivor group. In the group with chronic passive congestion, the postoperative course of 5 of 16 (31.3%) patients with valvular disease was poor. Serum cholinesterase concentration was lower only in the nonsurvivor group (nonsurvivor vs survivors: 2006+/-435 vs 3483+/-1442 IU/L, p < 0.02), and all patients with cholinesterase < 2000 IU/L died. Postoperative bleeding was greater in the nonsurvivor group (3327+/-2106 vs 1428+/-643 mL, p < 0.05). Multivariate logistic regression analysis including the described pre- and intraoperative factors identified only serum cholinesterase concentration (F = 9.18) as significant. CONCLUSIONS: A low value of preoperative serum cholinesterase (< 2,000 IU/L) is thought to be the predictor of prognosis after open heart surgery in patients with severe posthepatitis and congestive liver dysfunction. Operative factors (cardiopulmonary time in posthepatitis liver dysfunction and postoperative bleeding in the congestive liver dysfunction) also influenced the prognosis.

Adolescent↗

Structure and function of prostanoid receptors.

We have recently cloned cDNAs for the human and mouse TXA2/PGH2 receptors and a cDNA for the mouse PGE receptor. Sequencing, homology and hydrophobicity analyses revealed that they are proteins of 343, 341 and 365 amino acid residues, respectively, and all are rhodopsin-type receptors with putative seven transmembrane domains. Homology between the human and mouse TXA2 receptors is 76% in total and that between the human TXA2 and mouse PGE receptors is 38%. The homology increases in the putative transmembrane regions to 85 and 45%, respectively, and there observed several features common to the three receptors. These results indicate that the prostanoid receptors constitute a family of receptors of similar structure. The cloned PGE receptor showed binding activity specific to so-called EP3 agonists, which verified for the first time that pharmacologically defined PGE receptor subtypes consist of different molecules. This receptor also displayed different efficiency in signal transduction to an EP3 agonist, M & B-28767, and PGE2, providing an interesting model for the analysis of receptor-G protein coupling. In addition to the above biochemical results, these studies have revealed the characteristic tissue distribution of these receptors, which will open up a new biology of these prostanoids.

Amino Acid Sequence↗