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Biomedical subjects

T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Chemotherapy for unresectable recurrent or metastatic squamous cell carcinomas of the head and neck].

The efficacy of chemotherapy for unresectable recurrent or metastatic squamous cell carcinomas of the head and neck can not be proved by survival periods. However, the efficacy of chemotherapy has been observed in some select patients. We investigated the effect of chemotherapy for unresectable recurrent squamous cell carcinomas of the head and neck. Four patients with a good performance status (PS) were treated with high-doses of leucovorin (LV), cisplatin (CDDP), and 5-fluorouracil (5-FU). The regimen consisted of 25 mg/m2 of CDDP on days 1-5; 600 mg/m2 of 5-FU of days 2-6; and 200 mg/m2 of LV on days 1-6. Patients received 3 cycles of this regimen at 28-day intervals. Ten patients with a poor PS were treated with low-doses of CDDP and tegafur.uracil upon admission. The regimen of seven poor PS patients consisted of 8 mg/m2 of CDDP on days 1-5 and 8-12, and 400 mg/body of tegafur.uracil administered orally on days 1-14. The other three patients received chemotherapy on an outpatient basis for ten weeks. The weekly regimen consisted of 7.5 mg/m2 of CDDP on days 3 and 6 and 400 mg/body of tegafur.uracil administered orally on days 1-7. With respect to the LV + CDDP and 5-FU treatment, complete remission was obtained in one patient. Two patients showed no change (NC), while one patient developed a progressive disease (PD). This regimen is highly toxic, has severe side effects including myelosuppression, oral mucositis, and diarrhea, and has a survival period of between 16 and 32 weeks. The low-dose CDDP + tegafur.uracil treatment produced a partial response in three patients, NC in three patients, and four patients developed a PD. This regimen doses not have any severe side effects and has a survival period of between 4 and 67 weeks.

Aged↗
PubMed2000

Midgut malrotation in adulthood.

A 29-year-old man was admitted to our hospital with a history of recurrent right upper quadrant abdominal pain and vomiting. These symptoms appeared intermittently for 7 years. Various examinations revealed a diagnosis of midgut malrotation. Laparotomy was performed and revealed reverse rotation of the duodenum with paraduodenal hernia and a normal rotating colon. This case suggests that recurrent abdominal complaints in an adult should arouse suspicion of midgut malrotation.

Abdominal Pain↗
PubMed1999

Molecular cloning of an apoptosis-inducing protein, pierisin, from cabbage butterfly: possible involvement of ADP-ribosylation in its activity.

We have previously reported that the cabbage butterfly, Pieris rapae, contains a 98-kDa protein, named pierisin, that induces apoptosis in a variety of human cancer cell lines. In the present study, sequencing and cloning of a cDNA encoding pierisin was accomplished. PCR-direct sequencing showed that the gene encodes an 850-amino acid protein with a calculated molecular weight of 98,081. An intact clone at the amino acid level encompassing the entire coding region was obtained by recombination of two independent clones, and the molecular mass of its in vitro expressed protein was about 100 kDa on SDS/PAGE, the same as that of purified native pierisin. The expressed protein induced apoptosis in human gastric carcinoma TMK-1 and cervical carcinoma HeLa cells, like the native protein, indicating functional activity. The deduced amino acid sequence of pierisin showed 32% homology with a 100-kDa mosquitocidal toxin from Bacillus sphaericus SSII-1. In addition, pierisin showed regional sequence similarities with ADP-ribosylating toxins, such as the A subunit of cholera toxin. A glutamic acid residue at the putative NAD-binding site, conserved in all ADP-ribosylating toxins, was also found in pierisin. Substitution of another amino acid for glutamic acid 165 resulted in a great decrease in cytotoxicity and induction of apoptosis. Moreover, inhibitors of ADP-ribosylating enzymes reduced pierisin-induced apoptosis. These results suggest that the apoptosis-inducing protein pierisin might possess ADP-ribosylation activity that leads to apoptosis of the cells.

ADP Ribose Transferases↗
PubMed1999

Deletions or specific substitutions of a few residues in the NH(2)-terminal region (Ala(3) to Thr(9)) of sarcoplasmic reticulum Ca(2+)-ATPase cause inactivation and rapid degradation of the enzyme expressed in COS-1 cells.

Amino acid residues in the NH(2)-terminal region (Glu(2) - Ala(14)) of adult fast twitch skeletal muscle sarcoplasmic reticulum Ca(2+)-ATPase (SERCA1a) were deleted or substituted, and the mutants were expressed in COS-1 cells. Deletion of any single residue in the Ala(3)-Ser(6) region or deletion of two or more consecutive residues in the Ala(3)-Thr(9) region caused strongly reduced expression. Substitution mutants A4K, A4D, and H5K also showed very low expression levels. Deletion of any single residue in the Ala(3)-Ser(6) region caused only a small decrease in the specific Ca(2+) transport rate/mg of SERCA1a protein. In contrast, other mutants showing low expression levels had greatly reduced specific Ca(2+) transport rates. In vitro expression experiments indicated that translation, transcription, and integration into the microsomal membranes were not impaired in the mutants that showed very low expression levels in COS-1 cells. Pulse-chase experiments using [(35)S]methionine/cysteine labeling of transfected COS-1 cells demonstrated that degradation of the mutants showing low expression levels was substantially faster than that of the wild type. Lactacystin, a specific inhibitor of proteasome, inhibited the degradation accelerated by single-residue deletion of Ala(3). These results suggest that the NH(2)-terminal region (Ala(3) -Thr(9)) of SERCA1a is sensitive to the endoplasmic reticulum-mediated quality control and is thus critical for either correct folding of the SERCA1a protein or stabilization of the correctly folded SERCA1a protein or both.

Animals↗
PubMed1999

Mutations of Arg198 in sarcoplasmic reticulum Ca2+-ATPase cause inhibition of hydrolysis of the phosphoenzyme intermediate formed from inorganic phosphate.

Arg198 of sarcoplasmic reticulum Ca2+-ATPase was substituted with lysine, glutamine, glutamic acid, alanine, and isoleucine by site-directed mutagenesis. Kinetic analysis was performed with microsomal membranes isolated from COS-1 cells which were transfected with the mutated cDNAs. The rate of dephosphorylation of the ADP-insensitive phosphoenzyme was determined by first phosphorylating the Ca2+-ATPase with 32Pi and then diluting the sample with non-radioactive Pi. This rate was reduced substantially in the mutant R198Q, more strongly in the mutants R198A and R1981, and most strongly in the mutant R198E, but to a much lesser extent in R198K. The reduction in the rate of dephosphorylation was consistent with the observed decrease in the turnover rate of the Ca2+-ATPase accompanied by the steady-state accumulation of the ADP-insensitive phosphoenzyme formed from ATP. These results indicate that the positive charge and high hydrophilicity of Arg198 are critical for rapid hydrolysis of the ADP-insensitive phosphoenzyme.

Adenosine Diphosphate↗
PubMed1999

Formation of the ADP-insensitive phosphoenzyme intermediate in the sarcoplasmic reticulum Ca2+-ATPase of which both Cys344 and Cys364 are modified by N-ethylmaleimide.

Sarcoplasmic reticulum vesicles were pretreated with N-ethylmaleimide under the conditions in which both Cys344 and Cys364 (SHD) of the Ca2+-ATPase are selectively modified. Effects of the modification on the transition of the phosphoenzyme intermediate (EP) from ADP-sensitive form to ADP-insensitive form and on the formation of ADP-insensitive EP from Pi were examined without added K+. At pH 7.0-8.0 in totally aqueous media, the EP transition and the EP formation from Pi were almost completely inhibited by the SHD modification. The formation of ADP-insensitive EP from ATP and from Pi in the SHD-modified enzyme occurred to some extent at pH 6.0-6.5 and were greatly increased by addition of dimethyl sulfoxide at pH 6. 0-8.0. The inhibition by the SHD modification of the EP formation from Pi in the absence of dimethyl sulfoxide was attributed to a decrease in the equilibrium constant for the EP formation from the enzyme-Pi-Mg complex. When 40% (v/v) dimethyl sulfoxide was present, almost all the phosphorylation sites in the SHD-modified enzyme were phosphorylated with ATP at pH 6.0 or with Pi at pH 6.0-7.0, and all the EP formed was ADP-insensitive. These results lead to the possibility that the previously reported exclusion of water from the catalytic site upon the EP transition and upon the EP formation from the enzyme-Pi-Mg complex is inhibited by the SHD modification. The present study has revealed the conditions in which the enzyme is released from the inhibition by this modification. The modification of SHD, which brackets the phosphorylation site (Asp351), may provide a useful tool for the analysis of conformational changes at the phosphorylation site occurring in the catalytic cycle.

Adenosine Diphosphate↗
PubMed1999

Effects of 1alpha,25-dihydroxycholecalciferol and cortisol on the growth and differentiation of primary cultures of mouse mammary epithelial cells in collagen gel.

We examined the effects of 1alpha,25-dihydroxycholecalciferol (1,25-DHCC) and the glucocorticoid, cortisol, on primary mouse mammary epithelial cells in collagen gel cell culture systems. Physiological low concentrations (10(-11)-10(-9) M) of 1,25-DHCC stimulated growth of the cells in a collagen gel matrix culture in serum-free DMEM+Ham's F12 (1:1) medium containing BSA, EGF and cholera toxin, and the cell number reached 1.8-fold the control after 6 d in culture. In contrast, supraphysiological concentrations (10(-8)-10(-7) M) of 1,25-DHCC suppressed cell growth. Cortisol produced similar, but smaller, dose-dependent effects. The addition of serum to the culture medium masked the stimulatory effect of 1,25-DHCC and both the stimulatory and inhibitory effects of cortisol. 1,25-DHCC also affected casein synthesis by cells cultured in a serum-free floating collagen gel culture containing prolactin, insulin and cortisol, enhancing synthesis at low concentrations (10(-11)-10(-9) M) and inhibiting it above 10(-8) M. In the absence of cortisol, no detectable change in casein synthesis was induced by 1,25-DHCC. These results suggest a physiological role for 1,25-DHCC in stimulating both growth and differentiation of mouse mammary epithelial cells, though 1,25-DHCC does not substitute for glucocorticoids in the differentiation of the cells.

Animals↗
PubMed1999

Role of diffusion-weighted echo-planar MRI in distinguishing between brain brain abscess and tumour: a preliminary report.

Our purpose was to evaluate diffusion-weighted (DW) echo-planar MRI in differentiating between brain abscess and tumour. We examined two patients with surgically confirmed pyogenic brain abscess and 18 with metastatic brain tumours or high-grade glioma, using a 1.5 T system. The apparent diffusion coefficient (ADC) of each necrotic or solid contrast-enhancing lesion was measured with two different b values (20 and 1200 s/mm2). All capsule-stage brain abscesses (4 lesions) and zones of cerebritis (2 lesions) were identified on high-b-value DWI as markedly high-signal areas of decreased ADC (range, 0.58-0.70 [(10-3 mm2/s; mean, 0.63)]). All cystic or necrotic portions of brain tumours (14 lesions) were identified on high-b-value DWI as low-signal areas of increased ADC (range, 2.20-3.20 [(10-3 mm2/s; mean, 2.70)]). Solid, contrast-enhancing portions of brain tumours (19 lesions) were identified on high-b-value DWI as high-signal areas of sightly decreased or increased ADC (range, 0.77-1.29 [(10-3 mm2/s; mean, 0.94)]). Our preliminary results indicate that DW echo-planar MRI be used for distinguishing between brain abscess and tumour.

Aged↗
PubMed1999

ELISA and immunoblot using purified glycoproteins for serodiagnosis of cysticercosis in pigs naturally infected with Taenia solium.

The establishment of reliable serological methods for cysticercosis in pigs is important for the surveillance, control and prevention of taeniosis/cysticercosis in humans as well as in pigs to prevent economic loss. Both ELISA and immunoblot using glycoproteins (GPs) purified by a single step of preparative iso-electric focusing, which are highly useful for human cysticercosis, have been applied for a serological study in pigs naturally infected with Taenia solium. All sera from pigs showed similar responses to those in human cysticercosis. Therefore, it is expected that both ELISA and immunoblots using GPs would be useful in differentiating infected pigs from uninfected ones.

Animals↗
PubMed1999

Ulcerative colitis patients with a family history of colorectal cancer should be subjected to close and careful surveillance.

We report two cases affected by neoplasia after colectomy with ileo-rectal anastomosis (IRA) with a positive family history of colon cancer. Case 1, a 41-year-old ulcerative colitis (UC) patient, underwent IRA in 1977. In 1986, biopsies showed high-grade dysplasia. She underwent resection of the rectal stump in 1986. Submucosal invasive carcinoma was found in the surgical specimen. The immunohistological study demonstrated p53 protein overexpression in the neoplastic lesion. Her family history fulfilled the Amsterdam criteria of hereditary non-polyposis colorectal cancer (HNPCC). Case 2, a 47-year-old UC patient, underwent ascending colostomy in 1975 and the following year IRA. Endoscopic mucosal resection (EMR) for a sessile adenoma was performed in 1995 and subsequently polypectomy was performed for the residual tumor. Recurrent adenoma and dysplasia in another area were detected. The immunohistological study demonstrated p53 protein overexpression only in dysplasia. Renal cancer in the right kidney was detected. Resection of the rectal stump with ileal pouch-anal anastomosis (IAA), loop ileostomy and right nephrectomy were performed in 1998. Her mother and her mother's sister had been diagnosed with colon cancer. Only in the dysplastic lesion did we detect microsatellite instability at D5S644. Both cases with neoplasia had two relatives with colorectal carcinoma. In 33 cases with UC who had been followed up, 30 cases (96.8%) without neoplasia had no family history of colorectal carcinoma. These findings suggest that UC patients with a family history of colon cancer should be put under close surveillance. It should also be emphasized that IAA is the procedure of choice for UC patients with this particular condition.

Adenoma↗
PubMed1999

Thallium-201 scintigraphy in malignant mesothelioma.

A patient with malignant pleural mesothelioma was investigated using 201Tl scintigraphy. There was diffuse pleural tumour accumulation on planar scintigraphy. Single photon emission computed tomography (SPECT) demonstrated exact tumour location. It is concluded that planar scintigraphy using 201Tl may be useful in detecting mesothelioma. Clearer tumour localization is possible with SPECT.

Female↗
PubMed1999

Diffusion-weighted echo planar imaging of acute brain infarction: a preliminary report.

The clinical usefulness of diffusion-weighted echo planar imaging (DW-EPI) was studied in 55 patients with acute brain ischemia. Ischemic lesions were identified on DW-EPI as hyperintense regions in all patients before changes were detected by conventional magnetic resonance imaging techniques in 12 cases studied earlier than 6 hours after onset. The earliest case was verified on DW-EPI at 50 minutes after onset. The ultra-fast imaging technique took less than 2 minutes to perform even for restless patients. Three patients had cardioembolic middle cerebral artery occlusion, and emergent percutaneous transluminal recanalization was carried out. Chronological changes in the signal of brain ischemia on DW-EPI depended on the site and size of the lesion, lacunar infarct of basal ganglia, and/or massive infarct due to major vessel occlusion, and were affected by associated hemorrhagic events. Coronal DW-EPI could more easily demarcate ischemia in the brainstem and/or cerebellum than axial scans when susceptibility artifacts were present. Coronal scans also demonstrated the site and direction of the pyramidal tract and its anatomical correlation with the lesions. DW-EPI has potential for the diagnostic and therapeutic planning of patients with acute brain ischemia.

Aged↗
PubMed1999

[A clinical study of inoperable head and neck cancers].

Thirty two patients with inoperable head and neck cancer seen at Jichi Medical School Hospital during the period 1978 to 1995 were analyzed. Distribution of the affected site was as follows: 15 cases of oropharynx, 12 of hypopharynx, and 3 of larynx. In order to study a better performance status, prognosis and side effects were compared between radiotherapy alone (17 patients) and combined radiochemotherapy (15 patients). Patients who received the combined therapy survived longer than those patients who received radiotherapy alone. Moreover, high QOL was obtained longer in the combined therapy. Therefore, we conclude that radiotherapy should be combined with chemotherapy for cases with inoperable head and neck cancer.

Aged↗
PubMed1999

[Combined chemotherapy with low-dose cisplatin, tegafur and uracil for head and neck squamous cell carcinomas].

The mechanism for the effect of cisplatin (CDDP) as a modulator for 5-fluorouracil (5-FU) has already been described. The effective AUC of serum 5-FU concentration with oral administration of tegafur and uracil (UFT) has been revealed. We administered a dose of 200-600 mg/body of UFT orally every day, and 3.5-10 mg/m2 of CDDP by drip infusion 5 days a week. Hospitalized patients were administered these agents for 2-5 weeks. Eleven patients were enrolled, including 4 with untreated pharyngeal squamous cell carcinoma (SCC), 5 with locoregional recurrent SCC, and 2 with pulmonary multiple metastases. The mean age of the patients was 71 years, and all patients had a PS 3. Of the 4 patients with untreated pharyngeal SCC, PR was noted in 3 and NC in one, for a response rate of 75%. Of the 11 patients with locoregional recurrent and pulmonary metastatic SCC, PR was noted in only one patient for a response rate of 14%. Although on average these patients died of the primary disease 150 days after chemotherapy, 4 patients later showed an improved PS stage, and could were able to leave the hospital. These 4 patients could stay home with a PS 0 or PS 1 for an average of 133 days, and survived with the disease for an average of 240 days after chemotherapy. No side effects were observed in any patients. In side of the low response rate for locoregional recurrent and pulmonary metastatic SCC, the present therapy was thought to be useful from the viewpoint of the quality of life.

Administration, Oral↗
PubMed1998

Diffusion-weighted echo-planar MRI of lacunar infarcts.

We studied 35 patients with lacunar infarcts, using diffusion-weighted echo-planar imaging (DW-EPI) at 1.5 T. The relative apparent diffusion coefficient ratio (ADCR) of each lesion was calculated and lesion conspicuity on DW-EPI was compared to that on images acquired with fast fluid-attenuated inversion recovery and T2-weighted fast spin-echo sequences. Acute small infarcts (within 3 days) were identified with DW-EPI as an area of decreased ADCR (range 0.33-0.87; mean 0.67) and high signal, subacute small infarcts (4-30 days) as a high-signal or isointense areas of decreased or nearly normal ADCR (0.54-0.98; 0.73), and chronic small infarcts (> 30 days) as low- or high-signal areas of nearly normal or increased ADCR (0.97-1.92; 1.32). In three patients, small infarcts of the brain stem in the hyperacute phase (within 6 h) were seen only with DW-EPI. In five patients, fresh small infarcts adjacent to multiple old infarcts could be distinguished only with DW-EPI.

Aged↗
PubMed1998

Soil factors influencing the distribution of Oncomelania quadrasi, the intermediate host of Schistosoma japonicum, on Bohol Island, Philippines.

Soil conditions essential to the survival of Oncomelania quadrasi on Bohol Island in the Philippines were examined to clarify the factors limiting distribution of the snail and to develop a method for breeding large numbers of the snail in the laboratory. Soil samples in and around snail habitats were analysed and used for breeding experiments in the laboratory. Experiments using paddy soil derived from different parent materials revealed that the numbers of juvenile snails hatched varied widely between several soil samples. The best soils for reproduction generally had a pH of 5.6-7.9 and > 200 mg of available CaO/100 g. These soil factors, in addition to shade and moisture, determine the optimum conditions for the breeding of O. quadrasi in the field as well as in the laboratory. The determination of the optimum conditions for laboratory breeding of O. quadrasi and other intermediate snail hosts should facilitate detailed study of the hosts and the development of better methods to control or eradicate schistosomiasis and other snail-transmitted diseases.

Animals↗
PubMed1998

A plasmid isolated from phytopathogenic onion yellows phytoplasma and its heterogeneity in the pathogenic phytoplasma mutant.

A 3.6-kbp DNA fragment was cloned from the extrachromosomal DNA of a pathogenic plant mollicute, onion yellows phytoplasma (OY-W). Sequence analysis of the fragment revealed an open reading frame (ORF) encoding the replication (Rep) protein of rolling-circle replication (RCR)-type plasmids. This result suggests the existence of a plasmid (pOYW1) in OY-W that uses the RCR mechanism. This assumption was confirmed by detecting the single-stranded DNA (ssDNA) of a replication intermediate that is specifically produced by the RCR mechanism. This is the first report on the identification of the replication system of this plasmid and the genes encoded in it. With a DNA fragment including the Rep gene region of pOYW1 used as a probe, Southern and Northern (RNA) blot hybridizations were employed to examine the heterogeneity between the plasmids found in OY-W and a pathogenic mutant (OY-M) isolated from OY-W. Multiple bands were detected in the DNA and RNA extracted from both OY-W and OY-M infected plants, although the banding patterns were different. Moreover, the copy number of plasmids from OY-W was about 4.2 times greater than that from OY-M. These results indicate constructive heterogeneity between OY-W and OY-M plasmids, and the possibility of a relationship between the plasmid-encoded genes and the pathogenicity of the phytoplasma was suggested.

Amino Acid Sequence↗