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Biomedical subjects

H Mimura

Publications and source records attributed to H Mimura.

At least 37 records · Page 2Linked to original sources
PubMed1996

Morphologic adaptation of temporomandibular joint after chincup therapy.

The purpose of this study was to clarify the morphologic changes of the temporomandibular joint (TMJ) after chincup application, with longitudinal TMJ cephalometric laminagraphs. The subjects were 19 prepubertal patients with true, mild skeletal Class III malocclusions with anterior crossbite. All underwent chincup therapy from the beginning of treatment. The control subjects were 16 patients with functional anterior crossbite, with normal jaw relationships. Cephalometric laminagraphs and lateral cephalograms were obtained before and after treatment. Statistical analysis of the data revealed the results as follows: (1) The chincup therapy changed the direction of growth of the mandible, especially, the ramus swing-back. (2) The chincup group showed a relatively more slender mandibular neck compared with the control group. (3) The condylar heads were bent forward after the chincup application, and the glenoid fossa was deepened and widened. The clearance between condyles and fossae was decreased by the orthopedic force of the chincup appliance.

Adaptation, Physiological↗
PubMed1995

Hepatectomy under extracorporeal circulation.

BACKGROUND: Resection of hepatic tumors located near the confluence of the hepatic vein or invading the inferior vena cava has become technically feasible and relatively safe by using venovenous bypass. However, some technical problems remain to be solved. METHODS: We performed three cases of hepatic resection under extracorporeal circulation combined with hypothermic perfusion. RESULTS: An unexpected hemorrhage was observed in all three cases for different causes. The patient of case 2 died of liver failure developed from fatty liver. Bile duct stenosis was observed in cases 1 and 3. CONCLUSIONS: Although hepatectomy under total vascular exclusion by use of Biopump is now considered a safe procedure, attention should be paid when this procedure is performed because some technical problems still remain.

Blood Loss, Surgical↗
PubMed1995

Comparison of different bonding materials for laser debonding.

The laser-aided removal of ceramic brackets from enamel surfaces was compared between two different adhesives. The selected bonding materials were Bis-GMA composite resin and 4-META MMA resin. Debonding forces were measured as the shear bond strength, perpendicular to the brackets. Debonding force, debonding time, total illuminated laser energy, and Modified Adhesive Remnant Index were discussed. Laser illumination was very effective for debonding in both resin groups. Enamel fracture was not observed in either laser illuminated groups, whereas two teeth were cracked in the Bis-GMA control group. For MMA resin, debonding force was sufficiently decreased at 3 watts output, whereas 7 watts output was needed for Bis-GMA resin samples. Total illuminated energies until the removal of the brackets were statistically lower in the MMA groups than in the Bis-GMA groups. Laser-focused adhesives tended to be removed with the brackets in the Bis-GMA groups, whereas they tended to remain on the tooth surface in the MMA groups. We concluded that debonding MMA resin with a laser is safer than debonding Bis-GMA resin with a laser.

Acrylic Resins↗
PubMed1995

Laparoscopic cholecystectomy: a multicenter study of 17 hospitals.

A study of 1,254 laparoscopic cholecystectomies performed at 17 hospitals affiliated with the Liver, Gallbladder, and Pancreas Research Group of the First Department of Surgery at Okayama University was undertaken to assess the current status and safety of this procedure. The data for 336 patients, comprising the initial 20 laparoscopic cholecystectomies performed at each institution, were compared with the data from the remaining 918 patients. Comparison of the two groups revealed the following: 1. the rates of intraoperative conversion to open cholecystectomy were 11.3% and 5.1% (P < 0.05), 2. the complication rates were 5.7% and 3.4%, and 3. the rates of bile duct injury were 2.4% and 1.1%, respectively. Compared with the first group, the bile duct injuries resulting from a lack of experience decreased in the second group, however, the incidence of these injuries occurring during avulsion of the gallbladder in difficult cases increased. These results suggest that the experience acquired during the initial 20 laparoscopic cholecystectomies led to a reduction in the rate of intraoperative conversion to open cholecystectomy, but it did not reduce the rate of complications, and that the risk of bile duct injury was always present.

Cholecystectomy, Laparoscopic↗
PubMed1995

Measurement of hepatic blood flow using 111In colloid.

The reduced hepatic blood flow calculated from hepatic scintigram with 198Au colloid was elucidated as the primary responsible factor for postoperative hepatic insufficiency. However 198Au colloid is no longer in use because of the high levels of radiation. Although 99mTc-phytate behaves similarly to 198Au on imaging, there were discrepancies between the hepatic blood flow index (KL) value and the severity of cirrhosis determined by laboratory data or by histology. In the measurement of hepatic blood flow using a radioactive colloid, factors like organ distribution, stability and uniformity of the colloid particles influence the values. In the present study, a 111In colloid was prepared and administered to rats to investigate the usefulness: as much as 95.4 (0.8) [Mean (+/- SD)]% of the colloid accumulated in the liver at pH 6.8. The distribution of particle diameter was within a relatively narrow range with the peak at 0.2 to 0.4 microns. Moreover, the KL values were not affected by condition of the reticuloendothelial system. The values showed a significant correlation with the measurements of the hepatic tissue blood flow obtained by the hydrogen gas clearance method (gamma = 0.83, P < 0.001). Thus, the 111In colloid can be clinically used as a substitute for 198Au colloid in the preoperative examination for estimation of the limit of resection.

Animals↗
PubMed1995

Extracorporeal circulation and hypothermic perfusion for caval tumor thrombus complicating hepatocellular carcinoma: a case report.

A tumor thrombus complicating hepatocellular carcinoma developed in a 61-year-old male patient. Embolization of the right branch of portal vein was performed 2 weeks before operation. Curative resection of the tumor was performed on by extended hepatectomy plus in situ hypothermic perfusion of the liver and extracorporeal circulation. Postoperative course was uneventful until bile leakage occurred on the 11th postoperative day. A bile duct stenosis was diagnosed by cholangiogram, and hepaticojejunostomy was carried out. The patient recovered well without further complications. The pitfalls and technical problems encountered in this case are herein discussed.

Carcinoma, Hepatocellular↗
PubMed1995

[Detection and localization of enlarged parathyroid glands in patients with hyperparathyroidism using 99mTc-methoxyisobutylisonitrile (MIBI): a study of subtraction scintigraphy with 99mTc-pertechnetate].

In this study we investigated the detectability of abnormal parathyroid gland(s) by 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy in patients with hyperparathyroidism. The subjects were 6 patients with primary hyperparathyroidism (PHP) with a single adenoma and 13 patients with renal hyperparathyroidism (RHP) on chronic maintenance hemodialysis. The imaging data of 99mTc-pertechnetate were subtracted from those of 99mTc-MIBI (MIBI-Tc), and number and location of the positive images on scintigrams were compared with those obtained by conventional scintigraphy using 201Tl-Cl and 99mTc-pertechnetate (Tl-Tc). All of the patients underwent surgery, and the number and location of the abnormal parathyroid glands were confirmed. The number of resected parathyroid glands were 6 in PHP and 52 in RHP. The detectability of MIBI-Tc was 83.3% in PHP and 51.9% in RHP, while that of Tl-Tc was 100% and 44.2%, respectively. Although no statistically significant difference in the detectability was found between MIBI-Tc and Tl-Tc, the number of false positives with MIBI-Tc was less than that with Tl-Tc. The detectability of MIBI-Tc depended on the size of the parathyroid gland. The maximal diameter and weight of the smallest parathyroid gland detected were 15 mm and 290 mg in PHP, and 9 mm and 50 mg in RHP. The existence of the thyroid gland did not reduce the detectability of MIBI-Tc. In conclusion, MIBI-Tc was clinically very useful for the detection of abnormal parathyroid glands in patients with hyperparathyroidism.

Adult↗
PubMed1995

[Study on tumor accumulation property of 99mTc-HM-PAO and 99mTc-MIBI in rabbits bearing VX-2 cancer].

Each of blood flow imaging agents has a potential usefulness as an agent for tumor scintigraphy. The usefulness for tumor scintigraphy of two agents, i.e. cerebral blood flow scintigraphy agent 99mTc-HM-PAO and myocardial blood flow scintigraphy agent 99mTc-MIBI, was comparatively studied using rabbits bearing VX-2 cancer. From then to twenty days after the implantation of VX-2 cancer into the femoral region of five rabbits, tumor to soft tissue accumulation ratio (T/S ratio) of each agent was calculated in early images (5 min after injection) and in late images (50 min after injection). Compared with 99mTc-MIBI, the T/S ratio of 99mTc-HM-PAO was higher and, moreover, the washout was delayed. These results suggest that there is a difference in tumor accumulation property between these two agents.

Animals↗
PubMed1995

Molecular cloning and characterization of S-adenosyl-L-methionine:scoulerine-9-O-methyltransferase from cultured cells of Coptis japonica.

S-Adenosyl-L-methionine:scoulerine-9-O-methyltransferase (SMT) catalyzes the transfer of the S-methyl group of S-adenosyl-L-methionine to the 9-hydroxyl group of scoulerine during the biosynthesis of berberine. We have isolated functionally active cDNA clones (pCJSMTs) from a cDNA library prepared from cultured cells of Coptis japonica. The longest cDNA insert (pCJSMT1) had an open reading frame that encoded 351 amino acids, but the calculated molecular mass (38,364 Da) of the deduced product was slightly lower than the experimentally determined molecular mass of purified SMT. Rapid amplification of the 5' end of the cDNA indicated that the full-length cDNA of SMT consisted of 1,458 nucleotides that encoded 381 amino acids. When the full-length cDNA was expressed in E. coli, the molecular mass of the expressed SMT was greater than that of native SMT in Coptis cells. This result suggests that SMT might be produced in a pre-mature form and processed post-translationally. SMT was also found to exhibit sequence homology to other O-methyltransferases from plants and N-terminal region of the SMT polypeptide appeared to be necessary for enzymatic activity.

Amino Acid Sequence↗
PubMed1995

Changes in IL-6 and IL-8 after hepatectomy in patients with liver cirrhosis.

Changes in tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and interleukin-8 (IL-8) were investigated before and after hepatectomy in patients with or without liver cirrhosis (5 cases without liver cirrhosis and 14 cases with liver cirrhosis). Both the IL-6 and IL-8 values of the cirrhotic patients were significantly higher on the first postoperative day (POD) as compared with the non-cirrhotic patients. Overall, no significant correlation was found between peak values of IL-6 or IL-8 and blood loss or operating time. In the case of the cirrhotic patients, correlation of both IL-6 and IL-8 with operating time was significant at p < 0.05, gamma = 0.534 and 0.586, respectively. No correlation was found between blood loss and the peak value of IL-6, but significant correlation (gamma = 0.647, p < 0.05) was found between them in cirrhotic patients. There was no consistent increase in TNF-alpha and IL-1 beta following hepatectomy. These findings indicate that procedures undertaken to reduce the excessive production of these cytokines may be useful for preventing complications after hepatectomy in cirrhotic patients.

Carcinoma, Hepatocellular↗
PubMed1994

Kupffer cell function in chronic liver injury and after partial hepatectomy.

The reticuloendothelial system (RES) plays an important role in the biological defense system. In the liver, Kupffer cells are the main constituent of the RES, and when their function is impaired postoperative complications may more often occur. By using 99mTc-labeled human serum albumin millimicrospheres (99mTc-HSA-MM) combined with assessment of single photon emission computed tomography (SPECT), we have attempted to determine the function of Kupffer cells independently of the hepatic blood flow. First, Kupffer cell function in rats with chronic liver injury caused by CCl4 was studied. The hepatic uptake rate in chronic liver injury was decreased, and a reduced phagocytic activity of the Kupffer cells was noted. The parameter concerning Kupffer cell degradation, the excretion rate (k), was markedly decreased in the early period of chronic liver injury. Changes in Kupffer cell function after 30% and 70% hepatectomy were also studied. After 30% hepatectomy, the excretion rate was decreased on the first postoperative day (POD), and it was increased beyond that found after sham operation on the 3rd POD. In contrast, slower recovery of uptake rate was demonstrated. After 70% hepatectomy, both uptake and excretion rates were markedly reduced, and recovery was prolonged beyond the 5th POD. The hepatic uptake was not parallel with the excretion rate in either experiment. These results suggest that the method that measures the hepatic excretion rate may provide a better assessment of Kupffer cell function than the current uptake measurement with radiolabeled colloid.

Animals↗