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Biomedical subjects

Hiroyuki Kato

Publications and source records attributed to Hiroyuki Kato.

At least 91 records · Page 5Linked to original sources
PubMed2003

Scaphotrapeziotrapezoid fusion: long-term follow-up study.

The long-term effectiveness of scaphotrapeziotrapezoid (STT) fusion is still controversial. We evaluated our clinical and radiological results of 30 STT fusions in 30 patients (average age 41 years; 23 males, 7 females). The follow-up period averaged 84 months. The indications were Kienböck's disease ( n= 23), isolated STT arthrosis ( n = 6), and dislocation of the trapezium ( n = 1). A total of 26 simultaneous associated procedures were performed. Excisional arthroplasty of the lunate was done in all 23 patients with Kienböck's disease. Of the 30 total patients, 5 had postoperative pain ranging from mild to severe; 4 patients were dissatisfied with the results. Postoperative ranges of motion of the wrist were 84% of extension and 91% of flexion compared with preoperative motion. The postoperative grip strength improved to 27 kgf from the preoperative value of 18 kgf. Altogether, 26 patients returned to their previous activities. All patients obtained uneventful STT fusion in an average of 11.2 weeks. Eight patients (27%) experienced postoperative complications; seven had radioscaphoid arthroses, five had trapeziometacarpal arthrodeses, and one had a flexor pollicis longus tendon rupture. Although radioscaphoid arthrosis occurred in 23% of this series after STT fusion, the results suggest that it is an effective procedure for Kienböck's disease and isolated STT arthrosis.

Adolescent↗
PubMed2003

Regulation of hemoglobin affinity for oxygen by carbonic anhydrase.

We studied the effect on hemoglobin (Hb)-oxygen affinity induced by changes in carbonic anhydrase (CA) activity. Oxygen partial pressure at the 50% saturation of Hb (P(50)) in human blood was measured as CA activity was inhibited to varying degrees with acetazolamide (AZ; 100 and 200 microg/mL). Transient but significant change in P(50) was observed when AZ was administered and the CO(2) concentration was changed from 10% to 5%. Finally, the differences induced with AZ were attenuated when the blood sample was subjected to 4 hours of tonometry. The findings in this study could be accounted for by reduced velocity of pH changes caused by the inhibition of CA by AZ. We conclude that CA can change Hb's affinity for oxygen by controlling the movement of CO(2) gas between air and liquid compartments.

2,3-Diphosphoglycerate↗
PubMed2003

The upstream regulator, Rsr1p, and downstream effectors, Gic1p and Gic2p, of the Cdc42p small GTPase coordinately regulate initiation of budding in Saccharomyces cerevisiae.

BACKGROUND: Cdc42p, a Rho family small GTPase, is essential for budding initiation in the yeast Saccharomyces cerevisiae. The homologous proteins Gic1p and Gic2p (Gic1/2p) are effectors of Cdc42p, but their precise functions remain unknown. Rsr1p/Bud1p is a Ras family small GTPase that controls the selection of the budding site. Previous observations suggested that Rsr1p-GTP recruits Cdc24p, a GDP/GTP exchange factor for Cdc42p, at the incipient bud site. However, this model only addresses how Rsr1p determines the budding site, because the rsr1 mutant normally initiates budding. RESULTS: Here we show that a rsr1 gic1 gic2 mutant fails to initiate budding, resulting in unbudded, large, and multinucleated cells. Expression of a dominant active or dominant negative mutant of RSR1 also inhibited the growth of the gic1 gic2 mutant, suggesting that cycling of Rsr1p between the GTP- and GDP-bound forms is required for budding initiation in the gic1 gic2 mutant. Among the mutations in effectors of CDC42, only the gic1 gic2 mutation demonstrated a synthetic lethal interaction with rsr1. Increased gene dosage of CDC42 suppressed defects in budding initiation of rsr1 gic1 gic2 mutants containing additional mutations in other effectors of CDC42, including BNI1, CLA4 or STE20. The polarized localization of Bni1p-GFP (green fluorescent protein) and Cla4p-GFP was lost after depletion of Gic1p in the rsr1 gic2 mutant. CONCLUSION: We propose that Gic1/2p may stabilize or maintain a complex consisting of Cdc42p-GTP and its effectors at the budding site, which are assembled by the action of the Rsr1p-Cdc24p system.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Acute posterior interosseous nerve palsy caused by septic arthritis of the elbow: a case report.

A rare case of acute posterior interosseous nerve palsy caused by septic elbow arthritis is reported. The nerve was compressed beneath the arcade of Frohse by hypertrophied synovium and joint fluid at the anterior aspect of the radial neck. Decompression of the nerve, synovectomy, and irrigation of the elbow joint were done. effective. Six months after the surgery the nerve palsy had recovered completely. Two years after surgery there was no recurrence of the infection or nerve palsy.

Adult↗
PubMed2003

Telescoping vascularized fibular graft: a new method.

The authors describe a case of congenital pseudarthrosis of the tibia treated with a telescoping vascularized fibular graft. The advantages of this new method are that bone union and leg-length discrepancy may be corrected simultaneously.

Bone Transplantation↗
PubMed2003

Correlation between serum melatonin circadian rhythm and intensive care unit psychosis after thoracic esophagectomy.

BACKGROUND: Intensive care unit (ICU) psychosis is still a relatively frequent complication after esophageal surgery. We investigated the correlation between ICU psychosis and serum melatonin concentration during the period after esophagectomy. METHODS: The study group comprised 41 patients who underwent esophagectomy for treatment of esophageal cancer between 1999 and 2001. The cohort included 36 men and 5 women, aged 36 to 78 years. After surgery, blood samples were collected 4 times a day for 4 days. Serum levels of melatonin were determined with a melatonin radioimmunoassay kit. The regularity of the melatonin circadian rhythm pattern, as defined by the frequency of occurrence of the peak level of melatonin secretion, was determined (the pattern was described as irregular at less than 3 times in the measurement period). RESULTS: Of the 41 patients who met the inclusion criteria, 11 (26.8%) had ICU psychosis develop. These patients were older than those patients in whom ICU psychosis did not develop (P =.01). No significant differences were seen in the duration of surgery, volume of blood loss, term in the ICU, term of intubation, tumor location, disturbances of organ function, and postoperative complications between patients in whom ICU psychosis developed, and those patients in whom it did not. Patients with ICU psychosis tended to have abnormally low serum levels of melatonin. Of the 41 patients studied, 9 (22%) had an irregular pattern of melatonin circadian rhythm. A significant correlation was seen between ICU psychosis and an irregular melatonin circadian rhythm (P =.0001). CONCLUSION: Irregular patterns of melatonin circadian rhythm may be associated with ICU psychosis. Supplementation with melatonin, or acceleration of melatonin secretion, may protect patients from development of ICU psychosis and may promote recovery to a normal mental state.

Adult↗
PubMed2003

Use of the "supercharge" technique in esophageal and pharyngeal reconstruction to augment microvascular blood flow.

BACKGROUND: Although gastric tubes are commonly used in thoracic esophageal reconstruction, sometimes circumstances are such that an alternative method must be found. On these occasions, pedicled jejunum transfer and colonic interposition are used. After reconstruction, partial necrosis can occur because of poor blood flow in the oral end of the segment used to restore esophageal continuity. To improve this blood flow, we created a technique-the "supercharge" technique-in which we perform additional microvascular blood flow augmentation. METHODS: The supercharge technique was performed in 82 esophageal reconstructions with microvascular blood flow augmentation. Reconstructive methods included a gastric tube in 5 patients, a gastric tube combined with a free jejunal graft in 2, an elongated gastric tube in 6, a pedicled colonic interposition in 26, and a pedicled jejunum in 43. Recipient vessels were located in the neck or chest regions. RESULTS: After microvascular blood flow augmentation, the color and blood flow of the transferred intestine appeared greatly improved. During the operation, thrombosis was noticed in 3 patients and successfully salvaged by reanastomosis. Partial graft necrosis of the oral end of the segment occurred in only 2 patients; 2 patients had anastomotic leakage. CONCLUSIONS: The risk of leakage and partial necrosis of the transferred gut conduit appear to be reduced by using the supercharge technique to augment microvascular blood flow. This reliable technique contributes to the successful reconstruction of esophageal defects.

Adult↗
PubMed2003

Predictors of clinical results of radial osteotomies for Kienböck's disease.

The factors affecting the clinical results after radial osteotomies for Kienböck's disease are unknown. In the current study, we reviewed the data of 41 patients treated with radial osteotomies for Kienböck's disease and analyzed which preoperative factors significantly affected the clinical results of these procedures. Lateral closing wedge osteotomies of the radius were done for 22 patients (six patients with Lichtman Stage II disease, three patients with Lichtman Stage IIIA disease, 12 patients with Lichtman Stage IIIB disease, and one patient with Lichtman Stage IV disease) with zero or positive ulnar variance, and radial shortenings were done for 19 patients (four patients with Stage II disease, two patients with Stage IIIA disease, 12 patients with Stage IIIB disease, and one patient with Stage IV disease) with negative ulnar variance. The mean age of the patients at surgery was 36 years and the average followup was 38 months. To statistically assess the prognostic factors, multiple regression analysis focused on the postoperative clinical score as a dependent variable and preoperative patient data as independent variables. In the current analysis, patient age was the preoperative factor most clearly predictive of clinical results after radial osteotomies for Kienböck's disease. We think that the lower effectiveness of radial osteotomies must be considered in doing these procedures for elderly patients.

Adolescent↗
PubMed2003

Synergistic decline in expressions of p73 and p21 with invasion in esophageal cancers.

The significance of the p73 gene, a homologue of the p53 gene, in esophageal cancers is not fully understood. In order to clarify the role of p73 expression in esophageal cancers, p73 expression was immunohistochemically investigated in 106 surgically resected esophageal cancers and the results were compared with various clinicopathological factors. In normal esophageal epithelium, the expression of p73 was observed only in the nuclei of basal cells. In esophageal cancers, p73 immunoreactivity was observed in all intraepithelial lesions except one cancer, and was reduced with cancer invasion, to 78% and 64% at superficial invasion and deep invasion sites, respectively. However, p73 expression was not correlated with any other clinicopathological factor. The expressions of p53 and p21 were also investigated in esophageal cancer. To evaluate the status of the p53 gene mutation immunohistochemically, two monoclonal antibodies (DO7 and PAb240) were used. There seemed to be an inverse correlation between p73 expression and p53 mutation. Moreover, the expression of p21 was highly correlated with p73 expression irrespective of the p53 mutation status. In human esophageal cancers, p73 expression decreased with increasing degree of tumor invasion, and its decreased expression in local advanced tumor caused down-regulation of p21 expression, which might reflect tumor progression.

DNA-Binding Proteins↗
PubMed2003

Treatment of scapholunate dissociation: ligamentous repair associated with modified dorsal capsulodesis.

We previously reported that our repair and/or reconstruction of the scapholunate interosseous ligament reduced the scapholunate dissociation and improved the clinical results. Re-evaluation of these patients after three years revealed that malrotation of the scaphoid advanced significantly although the clinical results declined only slightly. To prevent progression of scaphoid malrotation, a modified dorsal capsulodesis was subsequently added to the ligamentous repair of scapholunate dissociation. The records of 17 patients were available for this study. The time lapse from injury to surgical treatment ranged from four days to one year and six months. All but three patients were operated less than two months after the injury. All patients were followed for more than one year, with an average of 49 months. Clinical results were expressed by a modification of the point score method of Green and O'Brien. Scapholunate angles were measured on lateral X-ray films with the wrist in neutral position. Overall clinical results averaged 83 points (range: 25-100). The scapholunate angles averaged 49 degrees (range: 45-60). In the three patients, in whom the operation was performed more than 11 months after the injury, the clinical results averaged 38 points and scapholunate angles averaged 54 degrees, respectively. These clinical and X-ray results suggest that early repair of the scapholunate interosseous ligament along with a modified dorsal capsulodesis is a useful procedure in the treatment of scapholunate dissociation.

Adult↗
PubMed2003

Metanephric adenoma of the kidney with massive hemorrhage and necrosis: immunohistochemical, ultrastructural, and flow cytometric studies.

Metanephric adenoma of the kidney is rare. We report 2 cases of metanephric adenoma with massive hemorrhage and necrosis. Case 1, a 42-year-old Japanese woman, complained of abdominal pain. Case 2, a 41-year-old Japanese woman, complained of fever and lumbago. They underwent nephrectomy. The cut surface was solid and yellow with massive hemorrhage and necrosis. These tumors showed packed tubular and glomeruloid patterns. The tumor cells were uniform and small, with uniform, oval, and hyperchromatic nuclei and scant cytoplasm, and showed reactivity for cytokeratin, vimentin, and CD 57. The MIB-1 indexes were up to 0.63%. The DNA ploidy pattern was diploid. The tumor cells formed small tubular structures with lumina and microvilli. These features suggested that metanephric adenoma is a benign tumor of an immature epithelial nature.

Adenoma↗
PubMed2003

Distinctive clinicopathological characteristics in esophageal squamous cell carcinoma.

Esophageal cancer is an aggressive disease with a generally poor prognosis. Frequently, patients present late with obstructive symptoms indicating advanced tumors. Therefore, serial histopathological investigations of esophageal cancer are now being performed more extensively, and several distinctive clinicopathological features have been demonstrated. In this review, we present some of the distinctive features of esophageal cancer and discuss their clinicopathological significance. These characteristics include: (1) the frequent presence of lymph node metastasis, (2) the morphological features and depth of tumor invasion, (3) the synchronous and metachronous occurrence of carcinoma of other organs, (4) the frequent coexistence of squamous epithelial dysplasia, (5) the frequent coexistence of intraepithelial spread, blood vessel, and lymphatic permeation, (6) the occasional existence of intramural metastasis, (7) the frequent coexistence of multiple primary carcinomas, and (8) the occasional coexistence of glandular differentiation with squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed2003

Further evidence of hepatic transdifferentiation in hepatoid adenocarcinomas of the stomach: quantitative analysis of mRNA for albumin and hepatocyte nuclear factor-4alpha.

AIMS: To assess the production of a liver-specific protein, albumin, and of a master transcriptional factor, hepatocyte nuclear factor (HNF)-4alpha, in hepatoid adenocarcinoma tissue. METHODS: Standard and quantitative RT-PCR, using five cases of hepatoid and three cases of non-hepatoid gastric adenocarcinoma. RESULTS: Hepatoid adenocarcinomas expressed similarly large amounts of albumin mRNA as those expressed in hepatocellular carcinoma and normal liver tissues. The observed amounts were several hundred times more than those in non-hepatoid adenocarcinoma and normal stomach tissues. HNF-4alpha mRNA was expressed in all stomach samples examined, and the levels of expression did not quantitatively differ between hepatoid and non-hepatoid adenocarcinomas of the stomach. CONCLUSIONS: These results provide further support of a relationship between hepatic transdifferentiation in hepatoid adenocarcinomas and albumin mRNA expression. Furthermore, transdifferentiation to the hepatocytic phenotype in hepatoid adenocarcinoma tissue was not directly associated with HNF-4alpha expression, thus suggesting that transdifferentiation proceeds by a complicated mechanism.

Adenocarcinoma↗
PubMed2002

High-level expression of the Smad ubiquitin ligase Smurf2 correlates with poor prognosis in patients with esophageal squamous cell carcinoma.

Transforming growth factor beta (TGF-beta) regulates growth of various cells, and inactivation of the TGF-beta signaling pathway contributes to tumor progression. Smad2 is phosphorylated and activated by TGF-beta, resulting in the antiproliferative effects of TGF-beta signaling. Smurf2 (Smad ubiquitination regulatory factor 2) was identified as the Smad ubiquitin ligase that induces the ubiquitination and degradation of Smad2. This study was undertaken to elucidate the relationships between Smurf2 expression and the clinicopathological characteristics of patients with esophageal squamous cell carcinoma (SCC) and the correlation between Smurf2 and Smad2 expression. Surgical specimens obtained from 80 patients with esophageal SCC were subjected to immunohistochemical staining. Our data indicated that high-level expression of Smurf2 correlated with depth of invasion, lymph node metastasis, and a poor survival rate. We also found an inverse correlation between the expression of Smurf2 and Smad2. Western blotting analysis of esophageal SCC-derived cell lines revealed similar inverse correlations. We demonstrated that high-level expression of Smurf2 appears to correlate with tumor development and poor prognosis in patients with esophageal SCC and that alteration of Smad2 expression in the TGF-beta signaling pathway may be induced by enhancement of Smad2 degradation mediated by high-level expression of Smurf2.

Activin Receptors, Type I↗
PubMed2002

Is postoperative adjuvant chemotherapy useful for gallbladder carcinoma? A phase III multicenter prospective randomized controlled trial in patients with resected pancreaticobiliary carcinoma.

BACKGROUND: To the authors' knowledge, the significance of postoperative adjuvant chemotherapy in pancreaticobiliary carcinoma has not yet been clarified. A randomized controlled study evaluated the effect of postoperative adjuvant therapy with mitomycin C (MMC) and 5-fluorouracil (5-FU) (MF arm) versus surgery alone (control arm) on survival and disease-free survival (DFS) for each specific disease comprising resected pancreaticobiliary carcinoma (pancreatic, gallbladder, bile duct, or ampulla of Vater carcinoma) separately. METHODS: Between April 1986 and June 1992, a total of 508 patients with resected pancreatic (n = 173), bile duct (n = 139), gallbladder (n = 140), or ampulla of Vater (n = 56) carcinomas were allocated randomly to either the MF group or the control group. The MF group received MMC (6 mg/m(2) intravenously [i.v.]) at the time of surgery and 5-FU (310 mg/m(2) i.v.) in 2 courses of treatment for 5 consecutive days during postoperative Weeks 1 and 3, followed by 5-FU (100 mg/m(2)orally) daily from postoperative Week 5 until disease recurrence. All patients were followed for 5 years. RESULTS: After ineligible patients were excluded, 158 patients with pancreatic carcinoma (81 in the MF group and 77 in the control group), 118 patients with bile duct carcinoma (58 in the MF group and 60 in the control group), 112 patients with gallbladder carcinoma (69 in the MF group and 43 in the control group), and 48 patients with carcinoma of the ampulla of Vater (24 in the MF group and 24 in the control group) were evaluated. Good compliance (> 80%) was achieved with MF treatment. The 5-year survival rate in gallbladder carcinoma patients was significantly better in the MF group (26.0%) compared with the control group (14.4%) (P = 0.0367). Similarly, the 5-year DFS rate of patients with gallbladder carcinoma was 20.3% in the MF group, which was significantly higher than the 11.6% DFS rate reported in the control group (P = 0.0210). Significant improvement in body weight compared with the control was observed only in patients with gallbladder carcinoma. There were no apparent differences in 5-year survival and 5-year DFS rates between patients with pancreatic, bile duct, or ampulla of Vater carcinomas. Multivariate analyses demonstrated a tendency for the MF group to have a lower risk of mortality (risk ratio of 0.654; P = 0.0825) and recurrence (risk ratio of 0.626; P = 0.0589). The most commonly reported adverse drug reactions were anorexia, nausea/emesis, stomatitis, and leukopenia, none of which were noted to be serious. CONCLUSIONS: The results of the current study indicate that gallbladder carcinoma patients who undergo noncurative resections may derive some benefit from systemic chemotherapy. However, alternative modalities must be developed for patients with carcinomas of the pancreas, bile duct, or ampulla of Vater.

Adult↗
PubMed2002

Predictive value of blood flow in the gastric tube in anastomotic insufficiency after thoracic esophagectomy.

Anastomotic insufficiency is considered to be one of the most serious complications associated with esophageal reconstruction. The purposes of this study were to identify (1) the relationship between anastomotic insufficiency and tissue blood flow (TBF) in the gastric tube in the perioperative period, and (2) the effects of intravenous prostaglandin E1 (PGE1) on TBF in the gastric tube. The study group consisted of 44 patients who were to undergo esophagectomy for esophageal cancer. Intraoperative and postoperative TBF on the serosal side of the gastric tube were measured by laser-Doppler tissue blood flowmetry. The TBF of the Leakage(+) group (n = 5) was poorer than that of the Leakage(?) group (n = 39) during the intraoperative and postoperative periods. There was a significant difference in TBF between the two groups at postoperative day (POD) 3. There was a tendency in the PGE1(+) group (n = 18) to exhibit richer blood flow through the anastomosis than the PGE1(?) group (n = 26), intraoperatively, but the difference was not significant. Two of five Leakage(+) cases were also in the PGE1(+) group. There was no relationship between intraoperative medication with PGE1 and incidence of leakage. The TBF of three-field lymph node dissection and reconstruction of the retrosternal route group (n = 21) was poorer than that of the two-field lymph-node dissection and reconstruction of the posterior mediastinal route group (n = 23). The TBF in the gastric tube after esophagectomy may be a predictor of anastomotic insufficiency. However, PGE1 treatment in the intraoperative period alone is not effective in preventing anastomotic insufficiency.

Adult↗