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Biomedical subjects

H Katoh

Publications and source records attributed to H Katoh.

At least 55 records · Page 3Linked to original sources
PubMed2002

Genetic variation of symbiotic fungi cultivated by the macrotermitine termite Odontotermes formosanus (Isoptera: Termitidae) in the Ryukyu Archipelago.

Fungus-growing termites have a mutualistic relationship with their cultivated fungi. To improve understanding of genetic aspects of this relationship, we examined molecular markers in the fungus-growing termite Odontotermes formosanus and its fungi Termitomyces spp. from the Ryukyu Archipelago. Based on the polymorphic band patterns obtained from arbitrarily primed polymerase chain reaction methods, we constructed cladograms for related colonies of the termites and fungi. The resulting trees indicated that the termites display little genetic variation among the colonies, while the symbiotic fungi consist of two major genetic types. In addition, molecular phylogenetic trees of the symbiotic fungi based on internal transcribed spacer and 18S rDNA suggested that these two types of fungi are different species. We also demonstrated that the fungi comprising the fruiting bodies and fungus combs are identical, and that fungus combs are probably a monoculture within a single termite colony. Our results indicate that horizontal transmission of symbiotic fungi among termite colonies occurred during the evolutionary history of this symbiosis.

Animals↗
PubMed2002

Selective occlusion with fibrin glue under fistuloscopy: seven cases of postoperative management for intractable complex fistulas.

BACKGROUND AND STUDY AIM: Fistula occlusion is not achieved in some fistulas with complex branches. To obtain early fistula closure in such cases, we insert a double-lumen catheter into each fistula branch, with the aid of a guide wire positioned using a small-caliber endoscope, and attempt selective infusion of fibrin glue. PATIENTS AND METHODS: Following removal of foreign bodies and necrotic granulation, we applied the selective occlusion method under fistuloscopic control to seven intractable external fistulas with complex branches, in which fistula closure had not been obtained by a simple occlusion method (SOM). All the fistulas were complex with more than two branches. RESULTS: Fistula occlusion was obtained within 2 weeks in six of the seven patients, and there has been no sign of recurrence over a follow-up period of 4 - 59 months (average 29.8 months). CONCLUSION: Selective occlusion under fistuloscopy is highly effective for intractable external fistulas with complex branches.

Digestive System Surgical Procedures↗
PubMed2002

Seven-day triple therapy with omeprazole, amoxycillin and clarithromycin for Helicobacter pylori infection in haemodialysis patients.

BACKGROUND: Triple therapy is accepted as the treatment of choice for Helicobacter pylori eradication, but there is no consensus on how long the therapy should be maintained in haemodialysis (HD(+)) patients. Our aims in this study were to evaluate the safety and efficacy of the 7-day triple therapy in HD(+) patients. METHOD: Forty-seven HD(+) and 55 HD(-) patients with dyspepsia underwent endoscopy. The prevalence of H. pylori was detected by Giemsa stain, followed by the urea breath test (UBT). H. pylori(+) patients were scheduled to undergo 7-day triple therapy and the success of eradication was investigated by UBT. RESULTS: Forty-five (44%) patients were positive for H. pylori. Forty of them underwent triple therapy and 39 (98%) patients completed the treatment. Eradication was successful in 32 (82%) and unsuccessful in 7 (18%) patients. There was no significant difference between these groups in age, gender, endoscopic findings or HD, and only previous treatment was significant for eradication failure by univariate and multivariate logistic regression analysis. Side effects were observed in 2 (15%) of 13 HD(+) and 3 (11%) of 27 HD(-) patients, and one HD(-) patient had to stop medication because of severe nausea and vomiting. The eradication rate was 93% (28/30) in patients without previous treatment. The triple therapy was unsuccessful in 7 patients, and 4 of them again underwent 7-day triple therapy, but all resulted in failure. CONCLUSIONS: Seven-day triple therapy is safe and effective for primary treatment of H. pylori infection in both HD(+) and HD(-) patients, but a new treatment is necessary for patients with previous treatment.

Age Factors↗
PubMed2002

A case of inguinal endometriosis with difficulty in preoperative diagnosis.

An unusual case of endometriosis involving the right round ligament in a 40-year-old woman is presented. After giving birth to two children, she first noticed a tender mass in the right groin at the age of 36. It didn't change in size but pain appeared at the age of 38, disturbing her daily life. A poorly circumscribed elastic hard mass, measuring 3 cm in diameter, was palpable in her right inguinal region. Magnetic resonance imaging demonstrated a 2x3 cm mass in the right inguinal canal. At operation, a mass was found to be in continuity with the round ligament at the inguinal canal. Histological diagnosis was endometriosis. After operation, she was completely relieved of pain. It is important to include endometriosis in the differential diagnosis for painful inguinal masses in women of childbearing age.

Adult↗
PubMed2001

Characterization of genes encoding multi-domain proteins in the genome of the filamentous nitrogen-fixing Cyanobacterium anabaena sp. strain PCC 7120.

Computational analysis of gene structures in the genome of Anabaena sp. PCC 7120 revealed the presence of a large number of genes encoding proteins with multiple functional domains. This was most evident in the genes for signal transduction pathway and the related systems. Comparison of the putative amino acid sequences of the gene products with those in the Pfam database indicated that and PAS domains which may be involved in signal recognition were extremely abundant in Anabaena: 87 GAF domains in 62 ORFs and 140 PAS domains in 59 ORFs. As for the two-component signal transduction system, 73, 53, and 77 genes for simple sensory His kinases, hybrid His kinases and simple response regulators, respectively, many of which contained additional domains of diverse functions, were presumptively assigned. A total of 52 ORFs encoding putative Hanks-type Ser/Thr protein kinases with various domains such as WD-repeat, GAF and His kinase domains, as well as genes for presumptive protein phosphatases, were also identified. In addition, genes for putative transcription factors and for proteins in the cAMP signal transduction system harbored complex gene structures with multiple domains.

Bacterial Proteins↗
PubMed2001

RCAS1 as a tumour progression marker: an independent negative prognostic factor in gallbladder cancer.

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) induces apoptosis in immune cells bearing the RCAS1 receptor. We sought to determine RCAS1 involvement in the origin and progression of gallbladder cancer, and also implications of RCAS1 for patient survival. RCAS1 expression was examined immunohistochemically in 110 surgically resected gallbladder specimens. The gallbladders represented 20 cases of cholecystitis with no associated pancreaticobiliary maljunction; 23 cases of cholecystitis with pancreaticobiliary maljunction; 14 cases of adenomyomatosis; 7 adenomas; and 46 cancers. High expression of RCAS1 (immunoreactivity in over 25% of cells) was observed in 32 of the 46 cancers (70%), but not in other diseases, including pre-cancerous conditions. RCAS1 immunoreactivity was associated with depth of tumour invasion (P = 0.0180), lymph node metastasis (P = 0.0033), lymphatic involvement (P = 0.0104), venous involvement (P = 0.0224), perineural involvement (P = 0.0351) and stage by the tumour, nodes and metastases (TNM) classification (P = 0.0026). Thus, RCAS1 expression may be a relatively late event in gallbladder carcinogenesis, possibly promoting tumour progression. Cox regression multivariate analysis demonstrated RCAS1 positivity to be an independent negative predictor for survival (P = 0.0337; risk ratio, 12.690; 95% confidence interval, 1.216-132.423). High expression of RCAS1 significantly correlated with tumour progression and predicted poor outcome in gallbladder cancer.

Adult↗
PubMed2001

Expression of inducible nitric oxide synthase depresses beta-adrenergic-stimulated calcium release from the sarcoplasmic reticulum in intact ventricular myocytes.

BACKGROUND: beta-adrenergic hyporesponsiveness in many cardiomyopathies is linked to expression of inducible nitric oxide synthase (iNOS) and increased production of NO. The purpose of this study was to examine whether iNOS expression alters the function of the sarcoplasmic reticulum (SR) Ca(2+) release channel (ryanodine receptor, RyR) during beta-adrenergic stimulation. METHODS AND RESULTS: Expression of iNOS was induced by lipopolysaccharide (LPS) injection (10 mg/kg) 6 hours before rat myocyte isolation. Confocal microscopy (fluo-3) was used to measure Ca(2+) spark frequency (CaSpF, reflecting resting RyR openings) and Ca(2+) transients. CaSpF was greatly increased by the adenylate cyclase activator forskolin (100 nmol/L) in normal myocytes (iNOS not expressed), but this effect was suppressed (by 77%) in LPS myocytes (iNOS expressed). When NO production by iNOS was inhibited by aminoguanidine (1 mmol/L), there was a further increase in the forskolin-induced CaSpF in LPS myocytes (to levels similar to the forskolin-stimulated CaSpF in normal myocytes). This effect was also seen in myocytes isolated from a failing human heart. There was no effect of aminoguanidine on forskolin-stimulated CaSpF in normal myocytes. ODQ (10 micromol/L), an inhibitor of NO stimulation of guanylate cyclase, did not restore the forskolin-induced rise in CaSpF in LPS myocytes. Aminoguanidine also increased twitch Ca(2+) transient amplitude in LPS myocytes after forskolin application (independent of changes in SR Ca(2+) load). CONCLUSIONS: iNOS/NO depresses beta-adrenergic-stimulated RyR function through a cGMP-independent pathway (eg, NO- and/or peroxynitrite-dependent redox modification). This mechanism limits beta-adrenergic responsiveness and may be an important signaling pathway in cardiomyopathies, including human heart failure.

Animals↗
PubMed2001

Availability of lobe-selective bronchial blockade for video-assisted thoracic surgery: an initial experience with three cases.

BACKGROUND: Stable oxygenation and sufficient collapse of the lung are essential for video-assisted thoracic surgery (VATS). We performed the lobe-selective lung collapse technique with VATS for patients who had deteriorated lung function. METHODS AND RESULTS: CASE 1: A 75-year-old man who had undergone thoracoplasty showed spontaneous pneumothoraces in the contralateral side. Bullae were stapled successfully under complete isolation and collapse of diseased lobe. CASE 2: A 57-year-old woman who had undergone left lower lobectomy for lung cancer presented with another lung cancer in the right lower lobe. The right lower lobe bronchus was closed selectively, and basal segmentectomy was performed. CASE 3: A 60-year-old woman who had lost left lung function presented with right-side spontaneous pneumothoraces. The right upper lobe was collapsed selectively, and bullectomy was performed. CONCLUSION: Lobe-selective bronchial blockade may be beneficial when VATS is performed for selected patients with deteriorated lung function.

Adenocarcinoma↗
PubMed2001

Tumor-related leukocytosis is linked with poor prognosis in patients with lung carcinoma.

BACKGROUND: Tumor-related leukocytosis is a paraneoplastic syndrome that is encountered occasionally in the clinical course of patients with lung carcinoma. Recently, autonomous production of hematopoietic cytokines (granulocyte-colony stimulating factor [G-CSF], granulocyte-macrophage-colony stimulating factor [GM-CSF], and interleukin-6 [IL-6]) were identified in some of these patients. However, the incidence and clinical characterization of this phenomenon have not been clarified. METHODS: During a 7-year period, 227 patients with carcinoma of the lung were investigated, and 33 patients were diagnosed with tumor-related leukocytosis. Except for one patient with small cell lung carcinoma, the other 32 patients had nonsmall cell lung carcinoma, and the highest incidence is recognized in large cell carcinoma. These 33 patients were examined for serum G-CSF, GM-CSF, and IL-6 levels using enzyme immunoassays and enzyme-linked immunosorbent assays. Tumor specimens were stained for antihuman cytokine (G-CSF, GM-CSF, and IL-6) monoclonal antibodies. RESULTS: Sixteen patients showed high serum G-CSF levels, 4 patients showed high serum GM-CSF levels, and 18 patients showed high serum IL-6 levels. Twelve specimens stained positively against anti-G-CSF antibody. Two specimens stained positively against anti-GM-CSF antibody, and three specimens were stained positively against anti-IL-6 antibody, including one double positive specimen for both G-CSF and IL-6. All specimens that were positive for monoclonal antibodies were from patients with nonsmall cell lung carcinoma. These patients had a poor outcome compared with the other patients. CONCLUSIONS: Tumor-related leukocytosis and cytokine production frequently occur in the clinical course of lung carcinoma, and this phenomenon is related mainly to nonsmall cell lung carcinoma. Its occurrence appears to be an ominous prognostic sign in patients with lung carcinoma.

Adult↗
PubMed2001

An inhibitor of inducible nitric oxide synthase decreases forearm blood flow in patients with congestive heart failure.

OBJECTIVES: The functional activation of inducible nitric oxide synthase (iNOS) was evaluated as a source of nitric oxide (NO) in the forearm of patients with heart failure. BACKGROUND: Although endogenous NO is normally produced by constitutive NO synthase (cNOS) in patients with congestive heart failure (CHF), expression of iNOS provides an additional source of NO. However, there are no in vivo studies showing functional activation of iNOS in humans. METHODS: A nonselective NOS inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), and a selective inhibitor of iNOS, aminoguanidine, were administered intra-arterially in graded doses into the brachial arteries of 13 patients with CHF and 10 normal control subjects. Forearm blood flow (FBF) was measured simultaneously in the infused and noninfused arms by plethysmography. Arterial and venous plasma concentrations of nitrite/nitrate (NOx) were measured at baseline and at the highest dose of each drug. RESULTS: L-NMMA significantly reduced the FBF ratio between the infused and noninfused arms in both the control and patient groups (35 +/- 12% and 34 +/- 10%, respectively; both p < 0.001). Aminoguanidine at the same concentration significantly reduced the ratio in the patient group (15 +/- 9%, p < 0.01), with no change in the control group. The arterial NOx concentration was not affected by either drug; however, venous NOx concentrations were significantly decreased in both the control and patient groups by L-NMMA (18 +/- 5% and 18 +/- 17%, respectively; both p < 0.05) and in the patient group only by aminoguanidine (7 +/- 6%, p < 0.05). CONCLUSIONS: These findings suggest that NO production in the forearms of patients with CHF is induced partly by iNOS activation, whereas in normal subjects, it can be ascribed to cNOS activation.

Acetylcholine↗
PubMed2001

RhoA inhibits the nerve growth factor-induced Rac1 activation through Rho-associated kinase-dependent pathway.

The Rho family of small GTPases has been shown to be involved in the regulation of neuronal morphology, and Rac and Rho exert antagonistic actions in neurite formation. In this study, we have examined the cross-talk between Rac and Rho in relation to the nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. NGF induced a rapid activation of Rac1 and suppression of RhoA activity. Constitutively active RhoA, RhoA(V14), or constitutively active Galpha(12)-induced endogenous RhoA activation inhibited the NGF-induced Rac1 activation without any effect on the NGF-induced extracellular signal-regulated kinase activation. Moreover, Y-27632, an inhibitor of Rho-associated kinase, completely abolished the RhoA-induced down-regulation of the NGF-induced Rac1 activation. We also revealed that NGF induced a rapid recruitment of Rac1 to the cell surface protrusion sites and formed filamentous actin-rich protrusions. Activation of RhoA and Rho-associated kinase formed a thick ringlike structure of cortical actin filaments at the cell periphery and then inhibited the NGF-induced recruitment of Rac1 to protrusions. These results indicate that RhoA down-regulates the NGF- induced Rac1 activation through Rho-associated kinase, inhibiting the neurite formation.

Actins↗
PubMed2001

A risk-stratification model of non-small cell lung cancers using cyclin E, Ki-67, and ras p21: different roles of G1 cyclins in cell proliferation and prognosis.

A large number of biological factors that seem to have important prognostic significance have been identified in non-small cell lung cancers (NSCLCs). In the present study, we have characterized expression of cyclin D1 and cyclin E in a cohort of 217 resected NSCLCs from a single institution by immunohistochemistry to analyze their expression in relation to the growth fraction determined by Ki-67 and to prognosis, and then we have constructed a risk-stratification model of cancer death by multiple biological factors in p-stage I NSCLCs. The cyclin E labeling index (LI) was significantly associated with the Ki-67 LI (r = 0.45; P < 0.001). Tumors having high-level cyclin E expression (cyclin E LI > or =30%) showed a significantly higher Ki-67 LI than tumors having low-level cyclin E expression (cyclin E LI <30%; P < 0.001), whereas positive or negative cyclin D1 expression was not associated with the Ki-67 LI (P = 0.1). Cyclin E expression was a significant and independent unfavorable prognostic factor (hazards ratio = 2.09; P = 0.03), as reported previously (Clin. Cancer Res., 6: 11-16, 2000), whereas cyclin D1 expression was not. These findings indicate different roles of cyclin D1 and cyclin E in cell proliferation and in the prognosis of NSCLCs. Furthermore, we stratified this cohort of p-stage I NSCLCs into different survival groups by using biological factors, including cyclin E, Ki-67, and ras p21, which previously we have found to be independent prognostic factors among 10 factors studied in p-stage I NSCLCs. Four groups of patients with markedly different survivals were identified with 5-year survival rates that ranged from 96% for patients with no factors altered to 41% for patients with all three factors altered (P < 0.001). This combination of biological factors was a significant and independent prognostic factor (hazards ratio = 7.94; P = 0.001).

Aged↗
PubMed2001

Differential responses to nerve growth factor and epidermal growth factor in neurite outgrowth of PC12 cells are determined by Rac1 activation systems.

Neurite outgrowth of PC12 cells is induced by nerve growth factor (NGF) but not by epidermal growth factor (EGF). This differential response has been explained by the duration of mitogen-activated protein kinase (MAPK) activation; NGF induces sustained MAPK activation but EGF leads short-lived activation. However, precise mechanisms have not yet been understood. Here we demonstrate the difference between NGF and EGF in regulation of Rac1, a small GTPase involved in neurite outgrowth, in PC12 cells. NGF phosphoinositide 3-kinase dependently induces transient activation of Rac1 and accumulation of active Rac1 at protrusion sites on the cell surface, inducing filamentous actin-rich protrusions and subsequent neurite formation in a Rac1-dependent manner. On the other hand, EGF phosphoinositide 3-kinase independently induces more transient Rac1 activation but neither accumulates active Rac1 nor forms Rac1- and filamentous actin-rich protrusions. Difference in the Rac1 localization between NGF and EGF was also observed with the localization of exogenously expressed green fluorescent protein-tagged Rac1. The Rac1-mediated protrusion by NGF is independent of MAPK cascade, but the subsequent neurite extension requires the cascade. Thus, the differential activation of Rac1 and localization of active Rac1 contribute to the difference in the ability of NGF and EGF to induce neurite outgrowth, and we propose that the MAPK cascade-independent prompt activation of Rac1 and recruitment of active Rac1 at the protrusion sites trigger the initiation of neurite formation.

Animals↗
PubMed2001

A case of spindle cell carcinoma of the breast--long survival achieved by multiple surgical treatment.

Spindle cell carcinoma of the breast was formerly called carcinosarcoma, and is relatively rare. We report a case of spindle cell carcinoma of the breast. The patient was treated with multiple surgeries and achieved long-term survival. The patient was a 52-year-old woman, in whom small induration developed at the areola of the nipple of the right breast. The lesion was resected, and benign tumor was diagnosed pathologically. Four years later, she had recurrence at the scar, and a typical mastectomy was performed. A tumor developed again 5 years later; the lesional focus was at the scar of the right chest wall and invasion of the ribs and the sternum was noted. The sternum and the right costal cartilage of ribs 3-9 were dissected together. The right chest wall was reconstructed and adjuvant radiation therapy performed. Four years after this operation, tumor recurred near the scar and chest wall resection including part of the pericardial cavity and the left lung was performed. However, 6 months later, invasion of the mediastinum, heart and lung were noted. The patient died 16 years after the first surgery. Dermatofibrosarcoma protuberance of the breast was diagnosed at the second operation. However, the diagnosis was changed to spindle cell carcinoma of the breast following immunohistochemical studies. Spindle cell carcinoma of the breast is rare, and definitive histopathological diagnosis is often difficult. When spindle cell carcinoma is suspected, comprehensive diagnostic studies including immunohistochemical examinations should be performed. Even in case with multiple recurrences correctly performed operations may contribute to prolongation of survival.

Bone Neoplasms↗
PubMed2001

Analysis of predictive factors for recurrence after hepatectomy for colorectal liver metastases.

Hepatectomy for liver metastases from colorectal cancer has recently received general acceptance as a safe, potentially curative treatment. Most patients, however, die of recurrent disease after hepatectomy. The predictive factors for recurrence after first resection of liver metastases have not yet been clarified. The authors aimed to determine the factors that can predict recurrence, especially hepatic-only recurrence after hepatectomy for colorectal liver metastases. Seventy-six patients who underwent liver resection of colorectal metastases were studied retrospectively. Forty-seven (61.8%) of the patients had a recurrence. The patients' disease-free survival after first hepatectomy and the second recurrence sites were univariately and multivariately analyzed using 16 clinicopathologic variables. Wall invasion, lymph node metastases, lymphatic invasion, venous invasion of the primary tumor, 24 months or longer disease-free interval after resection of the primary colorectal cancer, and bilateral liver metastases significantly influenced the disease-free survival (log-rank test: p < 0.05). The multivariate analysis revealed that venous invasion of the primary tumor and bilateral hepatic metastases were independent risk factors for recurrence after hepatectomy. The liver was the only site of second recurrence in 23 patients. Patients with lymph node metastases and venous invasion of the primary tumor had a significant difference between hepatic-only and extrahepatic recurrence after first hepatectomy (chi-square test or Fishers' exact test: p < 0.05). Recurrence after hepatectomy was influenced more by factors associated with the primary colorectal cancer than factors surrounding the first liver metastases. Venous invasion of the primary colorectal cancer was the most important predictable factor for hepatic-only second recurrence.

Adult↗
PubMed2001

Portal venous dilatation and stenting for bleeding jejunal varices: report of two cases.

We present two patients who underwent a portal stent placement for bleeding jejunal varices of the afferent loop caused by extrahepatic portal venous stenosis. Case 1 involved a 66-year-old woman who developed bleeding jejunal varices due to extrahepatic portal venous stenosis 1 year after a pancreaticoduodenectomy with intraoperative radiation therapy. Percutaneous transhepatic balloon dilatation and stent placement were performed. Since undergoing the procedure, no bleeding has occurred. Case 2 concerned a 44-year-old woman who had a rupture and bleeding of jejunal varices 16 years after a choledocojejunostomy. Stenosis was observed from the right and left branches of the portal vein to its intrahepatic branches. Both balloon dilatation and stent placement were attempted. However, the stent could not be fully inserted into the intrahepatic portal vein. Portal stent placement is less invasive and radical, and therefore should be attempted for the treatment of extrahepatic portal venous stenosis. However, there are limits to its application if the stenosis extends to the intrahepatic branches of the portal vein.

Adult↗
PubMed2001

Comparison of Bassini repair and mesh-plug repair for primary inguinal hernia: a retrospective study.

The purpose of this study was to compare the mesh-plug repair with the Bassini repair for the treatment of primary unilateral inguinal hernias. Patients with primary unilateral inguinal hernias who underwent a Bassini repair (n = 118) between January 1992 and May 1996 and a mesh-plug repair (n = 113) between July 1996 and April 1998 were retrospectively reviewed. We recorded information regarding the types of hernia according to Nyhus classification, operation time, complications, postoperative recovery, and recurrence after surgery. The two groups were comparable regarding age, sex, side of hernia, types of hernia, and the follow-up interval. The operation time was 55 +/- 20min for Bassini repair and 54 +/- 18min for mesh-plug repair. There was no incidence of mesh infection in the mesh-plug repair cases. The amount of diclofenac sodium (suppository) was 307 +/- 222mg in the Bassini repair group and 132 +/- 182mg in the mesh-plug repair group (P < 0.0001). The length of hospital stay was 8.2 +/- 2.0 days in the Bassini repair group and 4.3 +/- 2.7 days in the mesh-plug repair group (P < 0.01). Nine patients (7.6%) in the Bassini repair group had recurrence, compared with one patient (0.9%) in the mesh-plug repair group. The recurrence-free survival in the mesh-plug repair group was significantly longer than that in the Bassini repair group (P = 0.03). In conclusion, patients with primary unilateral inguinal hernias who undergo a mesh-plug repair recover more rapidly and have less recurrence in comparison with those who undergo a Bassini repair.

Aged↗