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Biomedical subjects

T Kodama

Publications and source records attributed to T Kodama.

At least 343 records · Page 19Linked to original sources
PubMed1997

Regression of atypical lymphoid hyperplasia after eradication of Helicobacter pylori.

A rare case of endoscopic and histological regression of a gastric lymphoid mucosal lesion after eradication of Helicobacter pylori is reported. A 72-year-old man was suspected of having a low-grade B-cell gastric mucosa-associated lymphoid tissue (MALT) lymphoma by endoscopic and histological findings. Histology of biopsy specimens showed massive infiltration of atypical lymphocytes and lymphoepithelial lesions. Immunohistochemical staining revealed kappa light chain expression in the infiltrated atypical lymphocytes to be twofold that of lambda light chain. The above diagnosis was thus highly suspected but not confirmed. Antibiotic therapy was given on the basis of evidence of H. pylori infection. Successful eradication of H. pylori resulted in remarkable improvement of endoscopic and histological findings. Follow-up studies were carried out 8 months after eradication, with no evidence of relapse. The eradication of H. pylori appears to be an effective alternative therapy for B-cell lymphoproliferative disease, although longer follow-up and further studies are needed before this treatment can be established.

Aged↗
PubMed1997

Purification and characterization of pyruvate:ferredoxin oxidoreductase from Hydrogenobacter thermophilus TK-6.

Pyruvate:ferredoxin oxidoreductase was purified to electrophoretic homogeneity from an aerobic, thermophilic, obligately chemolithoautotrophic, hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6, by precipitation with ammonium sulfate and fractionation by DEAE-Sepharose CL-6B, polyacrylate-quaternary amine, hydroxyapatite, and Superdex-200 chromatography. The native enzyme had a molecular mass of 135 kDa and was composed of four different subunits with apparent molecular masses of 46, 31.5, 29, and 24.5 kDa, respectively, indicating that the enzyme has an alphabetagammadelta-structure. The activity was detected with pyruvate, coenzyme A, and one of the following electron acceptors in substrate amounts: ferredoxin isolated from H. thermophilus, FAD, FMN, triphenyltetrazolium chloride, or methyl viologen. NAD, NADP, and ferredoxins from Chlorella spp. and Clostridium pasteurianum were ineffective as the electron acceptor. The temperature optimum for pyruvate oxidation was approximately 80 degrees C. The pH optimum was 7.6-7.8. The apparent Km values for pyruvate and coenzyme A at 70 degrees C were 3.45 mM and 54 microM, respectively. The enzyme was extremely thermostable under anoxic conditions; the time for a 50% loss of activity (t50%) at 70 degrees C was approximately 8 h.

Amino Acid Sequence↗
PubMed1997

Choroidal osteoma in an infant.

PURPOSE: To report an 8-month-old infant with choroidal osteoma. METHOD: Case report. RESULTS: The patient, who had bilateral yellow stippling at the posterior pole, was followed up for 8 years. Both fundi developed creamy, irregular scalloped lesions. Computed tomography showed a bony plate at the posterior pole bilaterally. CONCLUSION: We believe that this is the youngest patient reported to have choroidal osteoma.

Bone Neoplasms↗
PubMed1997

Coupling of protein surface hydrophobicity change to ATP hydrolysis by myosin motor domain.

Dielectric spectroscopy with microwaves in the frequency range between 0.2 and 20 GHz was used to study the hydration of myosin subfragment 1 (S1). The data were analyzed by a method recently devised, which can resolve the total amount of water restrained by proteins into two components, one with a rotational relaxation frequency (fc) in the gigahertz region (weakly restrained water) and the other with lower fc (strongly restrained water). The weight ratio of total restrained water to S1 protein thus obtained (0.35), equivalent to 2100 water molecules per S1 molecule, is not much different from the values (0.3-0.4) for other proteins. The weakly restrained component accounts for about two-thirds of the total restrained water, which is in accord with the number of water molecules estimated from the solvent-accessible surface area of alkyl groups on the surface of the atomic model of S1. The number of strongly restrained water molecules coincides with the number of solvent-accessible charged or polar atoms. The dynamic behavior of the S1-restrained water during the ATP hydrolysis was also examined in a time-resolved mode. The result indicates that when S1 changes from the S1.ADP state into the S1.ADP.P1 state (ADP release followed by ATP binding and cleavage), about 9% of the weakly restrained waters are released, which are restrained again on slow P1 release. By contrast, there is no net mobilization of strongly restrained component. The observed changes in S1 hydration are quantitatively consistent with the accompanying large entropy and heat capacity changes estimated by calorimetry (Kodama, 1985), indicating that the protein surface hydrophobicity change plays a crucial role in the enthalpy-entropy compensation effects observed in the steps of S1 ATP hydrolysis.

Adenosine Triphosphate↗
PubMed1997

Increased expression of vascular endothelial growth factor in human hepatocellular carcinoma.

BACKGROUND/AIMS: Angiogenesis is critical for the development and progression of solid tumors. The purpose of this study was to evaluate the possible role of vascular endothelial growth factor (which is considered to be one of the most important factors involved in tumor-associated angiogenesis), in human hepatocellular carcinoma. METHODS: Vascular endothelial growth factor gene and protein expression were analyzed by means of Northern hybridization and immunohistochemical methods in 5 hepatocellular carcinoma cell lines. Secretion of vascular endothelial growth factor was evaluated by immunoblotting of conditioned medium of these hepatocellular carcinoma cells. Further, we compared the level of vascular endothelial growth factor expression in hepatocellular carcinoma tissues along with that in surrounding tumor-free tissues obtained from 20 patients. We also analyzed mRNA expression of Flt-1, one of the vascular endothelial growth factor specific high-affinity receptors, in hepatocellular carcinoma cell lines. RESULTS: Northern hybridization analysis and immunohistochemistry revealed that all cultured hepatocellular carcinoma cells exhibited a high level of vascular endothelial growth factor mRNA. In addition, vascular endothelial growth factor secretion by Hep G2, one of the hepatocellular carcinoma cell lines, was shown by Western blot. In vivo, we observed vascular endothelial growth factor expression in both hepatocellular carcinoma and non-hepatocellular carcinoma tissues. However, in 12 of 20 cases, vascular endothelial growth factor mRNA levels were significantly up-regulated in hepatocellular carcinoma tissues. In the majority of cases (10 out of 12 cases) with abundant tumor vascularity, vascular endothelial growth factor mRNA up-regulation in hepatocellular carcinoma tissues was observed. We failed to detect Flt-1 mRNA expression in hepatocellular carcinoma cells. CONCLUSIONS: This study suggests that the possibility that hepatocellular carcinoma cells overexpress the vascular endothelial growth factor gene and protein. These findings support the hypothesis that vascular endothelial growth factor is one of the important factors involved in the angiogenesis of hepatocellular carcinoma, and may even be involved in the development and/or progression of hepatocellular carcinoma itself.

Adolescent↗
PubMed1997

Influence of imaging parameters, flow velocity, and pulsatile flow on three-dimensional time-of-flight MR angiography: experimental studies.

OBJECTIVE: The purpose of this study is to evaluate the influence of imaging parameters (TR and flip angle), velocity and pulsatility of flow on three-dimensional time-of-flight magnetic resonance (3D TOF MR) angiography by using a flow phantom. METHODS: The 3D TOF MR angiography of a flow phantom was performed at 1.5-T with various TRs, flip angles and flow velocity. The influence of pulsatile flow was also evaluated. RESULTS: The imaging parameters and flow velocity affected the saturation effects of inflowing spins. Signal loss due to saturation of inflowing spins was more pronounced with a shorter TR, larger flip angle, or lower flow velocity. However signal intensity of stationary tissue were more suppressed with a shorter TR resulting in a larger signal difference to noise ratio of the flowing fluid. Velocity of the flow also affected the signal loss due to intravoxel phase dispersion, which was apparently observed with a stenotic tube. Pulsatility of flow resulted in decreased intensity of flowing fluid and in ghost artifacts along the phase-encoding and slice-select directions. The spacing between these ghosts and intensity of them were dependent on TR, flip angle and pulse rates. CONCLUSIONS: Understanding the influence of imaging parameters and flow characteristics is essential for evaluating the MR angiograms or for improving their quality.

Blood Flow Velocity↗
PubMed1997

Phase II study of high-dose dexamethasone-based association in acute and delayed high-dose cisplatin-induced emesis--JCOG study 9413.

Thirty-three patients with lung cancer receiving 80 mg m(-2) cisplatin were treated with high-dose dexamethasone (32 mg m(-2) on days 1-3, 16 mg m(-2) on day 4 and 8 mg m(-2) on day 5) combined with granisetron on day 1 and metoclopramide on days 2-5. Twenty-eight (85%) patients had no nausea or vomiting on day 1, and 16 (48%) achieved total control on days 1-5 with acceptable toxicity. High-dose dexamethasone for cisplatin-induced delayed emesis should be further evaluated in a phase III trial.

Antiemetics↗
PubMed1997

Phase I study of sequentially administered topoisomerase I inhibitor (irinotecan) and topoisomerase II inhibitor (etoposide) for metastatic non-small-cell lung cancer.

We conducted a phase I study of irinotecan (CPT-11) and etoposide (VP-16) given sequentially to untreated patients with metastatic non-small-cell lung cancer. Arm A: CPT-11 was given over 90 min on days 1-3 and VP-16 was given over 60 min on days 4-6. Arm B: VP-16 was given on days 1-3 and CPT-11 on days 4-6. G-CSF was given to all patients daily on days 7-17. Twenty-seven patients were entered randomly at the two arms. The major dose-limiting toxicities in arms A and B were granulocytopenia and diarrhoea. Transient elevations of transaminases and bilirubin were observed in both arms. The degree of the toxicities did not differ between the two arms. The maximum tolerated doses (MTDs) were 60 mg m-2 CPT-11 and 60 mg m-2 VP-16 in both arms. Of the 13 patients who received more than two cycles, two out of five achieved partial response (PR) at the first level of arm A and one out of four achieved PR at the second level of arm B. We conclude that these schedules of sequential CPT-11 and VP-16 administration were inappropriate because of severe toxicities.

Adult↗
PubMed1997

Cascade regulation of the two CRP/FNR-related transcriptional regulators (ANR and DNR) and the denitrification enzymes in Pseudomonas aeruginosa.

ANR, an analogue of Escherichia coli FNR, has been shown to be necessary for denitrification, arginine deiminase activity and cyanide production of Pseudomonas aeruginosa. Another CRP/FNR-related regulator, DNR, has also been shown to be necessary for denitrification. In this study, we have found that the transcription of the dnr gene is under the control of ANR. When the dnr gene was expressed by tac promoter in an anr mutant, the strain recovered the ability to grow under anaerobic conditions by denitrification. Nitrate, nitrite, nitric oxide and nitrous oxide reducing activities were expressed, and the structural genes for nitrite and nitric oxide reductases were transcribed under anaerobic conditions in the anr mutant strain transformed with the dnr gene. These findings suggest that the expression of the denitrification system is controlled not directly by ANR but indirectly via DNR. The arginine deiminase activity and cyanide production were not regulated by DNR.

Anaerobiosis↗
PubMed1997

Possibilities and limitations of endoscopic resection for early gastric cancer.

BACKGROUND AND STUDY AIMS: To date, the accepted criteria for endoscopic resection of early gastric cancer have been: a) elevated-type mucosal cancer less than 2 cm in size, and b) depressed-type mucosal cancer without ulceration less than 1 cm in size. In this study, we attempted to expand these indications. PATIENTS AND METHODS: Sixty patients with early gastric cancer who did not meet the above criteria underwent endoscopic treatment, and were divided into four groups: those with elevated tumours larger than 2 cm with submucosal invasion (group 1 a); those without submucosal invasion (group 1 b); those with depressed tumours larger than 1 cm (group 2); and those with ulcerated tumours (group 3). The patients were treated with endoscopic resection using a two-channel scope, followed by additional laser irradiation or heater-probe coagulation (combination therapy) if residual cells were found. Follow-up was by endoscopy and biopsy for more than two years. RESULTS: Endoscopic treatment was effective in 87% of the patients (52 of 60), half of whom required combination therapy. In submucosal cancers, endoscopic treatment was effective in 76% of patients (13 of 17). However, tumours with deep invasion into the submucosa could not be cured. Mucosal cancers larger than 20 mm could be completely resected in 44% of patients (eight of 18) using endoscopic resection, but all five patients with tumours larger than 30 mm had incomplete resections. CONCLUSIONS: These results indicate that complete resection using endoscopic resection alone is possible in early gastric cancers measuring up to 30 mm in diameter. Tumours larger than 30 mm, and those with deep submucosal invasion, cannot be curatively treated by the current endoscopic modalities.

Adult↗
PubMed1997

Gadolinium-enhanced 3D time-of-flight MR angiography. Experimental and clinical evaluation.

PURPOSE: To evaluate the influences of Gd-DTPA on 3D time-of-flight (TOF) MR angiography (MRA). MATERIAL AND METHODS: In an experimental study using a flow phantom, contrast 3D TOF MRA was performed at varying Gd-DTPA concentrations, flow rates, TRs and flip angles. In a clinical study, cranial 3D TOF MR angiograms using Gd-DTPA were obtained in 38 patients to evaluate the efficacy of Gd-DTPA in enhancing the diagnosis of intracranial vascular lesions. Visualization of the venous system and distal arterial branches on contrast MRA was compared with those of noncontrast MRA. RESULTS: In the experimental study, progressive signal loss of inflowing spins due to saturation was smaller with higher concentration of Gd-DTPA. The influences of Gd-DTPA on the saturation effect were more pronounced with a slower flow rate, shorter TR and larger flip angles. In the clinical study, i.v. administration of Gd-DTPA improved the visualization of the venous system and distal arterial branches on 3D TOF MRA. The diagnostic value of MRA was enhanced by Gd-DTPA in patients with intracranial vascular lesions such as vascular malformations and large aneurysms. CONCLUSION: The T1-shortening effect of Gd-DTPA reduced the signal loss of vessels with slow flow rate, and contrast MRA was particularly useful for evaluation of venous abnormalities. Compared with conventional MRA, shorter TRs and larger flip angles were considered beneficial in contrast MRA.

Adult↗
PubMed1997

A new technology for revascularization of cerebral embolism using liquid jet impact.

Revascularization time is the dominant factor in the treatment of acute cerebral embolism. In this paper we describe a rapid revascularization therapy using liquid jets generated by the interaction of gas bubbles with shock waves, which impact on the thrombi. The interaction of a shock wave with a gas bubble attached to an artificial thrombus which was inserted into a tube model of a cerebral artery was investigated. The shock wave was generated by detonating a microexplosive pellet. The overpressure of the shock wave was 3.0 +/- 0.6 MPa (n = 7) and 12.7 +/- 0.4 MPa (n = 3). The initial air bubble radii were varied from 0.87 mm to 2.18 mm. The subsequent collapse of the bubble was photographed using a high-speed framing camera, and the liquid jet penetrating into the artificial thrombus was visualized using x-ray photography. The penetration depth of the liquid jet increased with increasing bubble size. There was an optimal separation distance between the bubble and the shock wave source to obtain the maximum penetration depth. Liquid jets have the potential to penetrate through thrombi in as little as a few microseconds, and with very efficient ablation.

Adult↗
PubMed1997

Second-line chemotherapy for relapsed small cell lung cancer.

Between January 1985 and August 1991, 159 patients with small cell lung cancer received first-line chemotherapy and 123 (77%) were responders. Of these, 88 relapsed, the remainder having died of other or unknown diseases or being alive without carrying cancer. The relapsed patients were examined to evaluate the outcome of the treatment for relapsed small cell lung cancer and to identify the factors that would contribute to the response rates and the survival durations. Forty-eight of 88 relapsed patients received second-line chemotherapy. Of the 48, 3 were evaluated as showing a complete response, 13 as partial response, 9 as no change, 15 as progressive disease and 8 as not evaluable. The response rate was 33% (95% confidence interval 20.4-48.4%). The median survival time was 146 days. The duration and rate of response in first-line chemotherapy affected the response rates of the second-line chemotherapy, but without statistical significance (P = 0.058 and 0.067 respectively). Increased response duration, time off chemotherapy and previous response to first-line chemotherapy all had a positive effect on the survival times (P < 0.01). Relapsed small cell lung cancer still shows a response to second-line chemotherapy without lessening survival time, and thus clinical trials of new drugs or combination chemotherapeutic regimens for relapsed small cell lung cancer cases would be reasonably justified. Randomized comparative studies are warranted for determining the benefits of second-line chemotherapy for relapsed small cell lung cancer cases.

Adult↗
PubMed1997

Association between p53 mutation and clinicopathological features of non-small cell lung cancer.

Genetic alterations in exons 5-8 of the p53 gene, determined by single-strand conformation polymorphism and sequencing analyses, and the clinicopathological characteristics of 108 patients with non-small cell lung cancer were compared. Mutations in this gene were found in 37 of the 108 patients (34%): in 30% (23/76) of those with adenocarcinomas, 46% (12/26) of those with squamous cell, 33% (1/3) of those with large cell and 33% (1/3) of those with adenosquamous carcinomas. No associations between the incidence of p53 mutations and the histological or cytological subtypes of adenocarcinomas were found. The analysis of types of mutations, however, showed that GC transversion was relatively common in papillary and clara subtypes, whereas it accounted for only 17% at most of p53 mutations in tubular and bronchial surface epithelial cell subtypes of adenocarcinomas. Univariate analyses revealed that large tumor size, high nodal stage and positive vascular invasion of non-small cell lung cancers, and high nodal stage and high-grade nuclear atypia of adenocarcinomas were associated significantly with p53 mutations. Multivariate analyses showed that the tumor sizes of non-small cell lung cancer correlated with p53 mutations with marginal significance (P = 0.099) whereas nuclear atypia of adenocarcinomas correlated significantly (P = 0.028). No differences between the overall or relapse-free survival rates of patients with and without p53 mutations in non-small cell lung cancers or adenocarcinomas were found. These findings indicate that p53 mutations in adenocarcinomas of the lung are associated with the malignant phenotype of tumor cells, but not with patient survival.

Adenocarcinoma↗
PubMed1997

Idiopathic granulomatous mastitis: case report and review of the literature.

We report a case of idiopathic granulomatous mastitis in a 35-year-old Japanese woman, who came to our hospital complaining of a tender mass in her right breast. Because the results of initial aspiration cytology were considered highly suspicious for carcinoma, modified radical mastectomy was performed. However, the final histological diagnosis was granulomatous lobular mastitis with no evidence of malignancy. Idiopathic granulomatous mastitis is a rare inflammatory breast disease of unknown etiology. Since the clinical manifestations are similar to those of mammary carcinoma, this condition has been misdiagnosed as carcinoma and treated as such. A review of the literature revealed that idiopathic granulomatous mastitis has tended to occur in young patients with a history of childbirth or oral contraceptive usage. Clinical or imaging diagnosis has often been difficult. Complete resection or corticosteroid therapy can be recommended as the optimal treatment. Since 38% of patients experience recurrence, long-term follow-up is indicated.

Adrenal Cortex Hormones↗
PubMed1997

Purification and localization of a 25-kD porcine renal puromycin aminonucleoside-binding protein.

BACKGROUND: Reactive oxygen species (ROS) are considered to have a role in the progression of puromycin aminonucleoside (PAN) nephrosis. However, the exact mechanism by which PAN induces ROS in this model is little known. In the present study, we attempted to purify a candidate for the target protein from PAN nephrotoxicity. METHODS: Using PAN-affinity column chromatography, a series of PAN-binding proteins was isolated from porcine renal extracts. We produced a specific antibody against a 25-kD protein eluted from the PAN-affinity matrix, and then developed a method to purify this protein. A partial amino acid sequence of the 25-kD PAN-binding protein was determined, and its tissue distribution was examined by immunoblot and immunohistochemical studies. RESULTS: The purified 25-kD PAN-binding protein was identified as a renal homolog of a new member of NAD(P)H:quinone oxidoreductases (NQOs, EC 1.6.99.2) that suppress the semiquinone and superoxide anion formation in cells, designated NQO2. Immunoblot analysis revealed a higher expression of the 25-kD PAN-binding protein in the kidney, brain, and liver among porcine major organs. Immunohistochemical studies showed an intrarenal distribution of this protein in epithelial cells of the glomeruli and tubules, mesangial cells, and vascular smooth muscle cells. CONCLUSIONS: We have purified the renal homolog of NQO2 as a PAN-binding protein, and shown its unique tissue expression. PAN may bind to the NQO2 homolog and inhibit its function in the renal target cells. This is presumed to result in an increase of ROS in the kidney with PAN nephrosis.

Amino Acid Sequence↗
PubMed1997

Microsatellite instability in lung cancer patients 40 years of age or younger.

Lung cancer in the young, which has the characteristics of a higher incidence of adenocarcinoma, lower male-to-female ratio of the patients, and less frequent smoking history in the patients, may possibly be associated with genetic predisposition to cancers. We studied six microsatellite loci (D2S123, D3S659, D3S966, D5S346, WT1, and TP53) in 18 surgically treated lung cancer patients aged 25-40 years and nine control patients aged 62-74 to determine the presence of microsatellite instability (MSI) and to correlate its occurrence with clinicopathological characteristics. Of the 18 patients, 11 were female and seven were non-smokers. There were 15 adenocarcinomas and three squamous cell carcinomas, 15 (83%) of which had vascular invasion. MSI was positive in seven (39%) of 18 young patients and one (11%) of nine control patients. Moreover, MSIs in a half or more of six loci examined were demonstrated in five (28%) young patients, whereas no control patients showed such a high frequency of MSI. We observed no significant differences in clinical or pathologic parameters between cases with and without MSI. This result suggests that genetic factors play an important role in the development of lung cancer in young adults.

Adenocarcinoma↗