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Biomedical subjects

S Tomita

Publications and source records attributed to S Tomita.

At least 19 recordsLinked to original sources
PubMed1999

Transcription factor decoy to study the molecular mechanism of negative regulation of renin gene expression in the liver in vivo.

Renin is synthesized in high quantities in the juxtaglomerular cells of the kidney, but little or none is synthesized in the liver. Our previous in vitro and biochemical studies have demonstrated that tissue-specific expression of the mouse renin gene is regulated by the specific interaction between negative regulatory element (NRE) in the 5'-flanking region of the renin gene and NRE binding protein (NREB). In this study, we examined the hypothesis that this interaction between the NRE in the promoter region of the rat renin gene and the NREB in the liver contributes to the suppressed renin gene expression in this tissue in vivo. We used in vivo transfection of NRE transcription factor decoy (TFD) double-stranded oligonucleotide into the rat liver via portal vein infusion. A gel mobility shift assay showed that transfected NRE TFD blocked endogenous NREB binding with the rat renin gene. This resulted in enhanced hepatic renin mRNA expression, immunohistochemical detection of renin in the liver, and consequently, increased plasma renin concentration. Taken together, these results document the importance of NREB in the inhibition of renin gene expression in rat liver in vivo and suggest the possibility of in vivo renin gene modulation by the TFD approach.

Animals↗
PubMed1999

Interaction of a neuron-specific protein containing PDZ domains with Alzheimer's amyloid precursor protein.

A novel protein, human X11-like (human X11L), contains a phosphotyrosine interaction (PI) domain and two PDZ domains and displays 55.2% amino acid homology with the human X11 (human X11). The PI domain of human X11L interacts with a sequence containing the NPXY motif found in the cytoplasmic domain of Alzheimer's amyloid precursor protein. A construct lacking the carboxyl-terminal domain, which comprises two PDZ domains (N + PI), enhances PI binding to APP, whereas another construct lacking an amino-terminal domain relative to PI domain (PI + C) suppresses PI binding to APP. Overexpression of full-length human X11L (N + PI + C) in cells that express APP695 stably decreased the secretion of Abeta40 but not that of Abeta42. However, overexpression of the PI domain alone and the N + PI construct in cells did not affect the secretion of Abeta despite their ability to bind to the cytoplasmic domain of Alzheimer's amyloid precursor protein. These observations suggest that the amino-terminal domain regulates PI binding to APP and that the carboxyl-terminal domain containing PDZ motifs is essential to modulate APP processing. Because expression of the human X11L gene is specific to brain, the present observations should contribute to shedding light on the molecular mechanism of APP processing in Alzheimer's disease.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Characteristics of hepatocellular carcinoma in patients with negative virus markers: clinicopathologic study of resected tumors.

Fifty-one cases of resected hepatocellular carcinoma (HCC) were retrospectively analyzed to evaluate the clinicopathologic features of HCC in patients with negative virus markers. The data were compared between three groups: hepatitis B surface antigen positive (HB, n = 11), hepatitis C virus antibody positive (HC, n = 21), and non-BC (both HbsAg and HCVAb negative, n = 12). Seven patients were excluded from the study because of operative death (n = 3), a history of alcohol abuse (n = 3), or the presence of dual positive HB and HC virus markers (n = 1). The data were analyzed by either an analysis of variance (ANOVA) or a contingency table. The age of the non-BC patients was higher (63.0 +/- 4.1, +/- SE) than that of HB patients (54.0 +/- 3.2, p < 0.05) but was identical to that of the HC group (62.0 +/- 1.8). Among the preoperative laboratory data, the serum glutamic oxaloacetate and glutamate pyruvate transaminoses (GOT, GPT) levels were statistically lower in the non-BC patients (32.8 +/- 4.8 and 28.0 +/- 4.4 IU/L, respectively) than in the HB and HC patients. The pathologic features of the resected specimens in the non-BC patients showed more invasive growth than in specimens from the HB or HC patients. The clinical stages (defined based on the criteria of the Japanese Association of Hepatocellular Carcinoma) were also more advanced in the non-BC patients than in the other groups. Postoperative survival time showed no significant difference among the groups. In conclusion, the non-BC patients had comparatively greater invasive growth and more advanced clinical stages than the HB and HC patients, despite the absence of liver cirrhosis, and so demonstrated the same poor survival data as observed in the HB and HC patients.

Adult↗
PubMed1999

Massive rectal bleeding due to ileal tuberculosis.

A patient with massive rectal bleeding due to ileal tuberculosis is reported. Technetium-99m labelled red blood cell scintigraphy indicated hemorrhage from the ileum, and laparotomy was then carried out. A 70-cm segment of ileum containing ulcers and erosions was resected, and epitheloid granuloma with Langhans-type giant cell was found in the resected specimen. Massive rectal bleeding is considered a rare presenting symptom of intestinal tuberculosis. Intestinal tuberculosis, including small intestinal tuberculosis, although uncommon, should be taken into consideration as a cause of rectal bleeding.

Feces↗
PubMed1999

A new method for magnetoencephalography: a three-dimensional magnetometer-spatial filter system.

A novel three-dimensional magnetometer-spatial filter system was developed to study human brain activity with high spatiotemporal resolution. The system combines the high temporal resolution of magnetoencephalography with the high spatial resolution achieved by using three-dimensional magnetometers and spatial filters to measure the direction and intensity of magnetic fields generated during brain activity. Simulation and phantom studies indicate that the system is capable of mapping current sources of magnetic fields with a spatial resolution comparable to that of any other brain functional imaging technique while maintaining millisecond temporal resolution. Application of this system to the human brain resolved magnetoencephalographic responses evoked by motion stimuli on a millisecond scale into responses occurring in visual cortical areas V1, V2/3 and V5. It also revealed signals related to contextual modulation in V1 and V2/3. This system provides a new way of studying the dynamics of human brain function.

Brain↗
PubMed1999

Analyses of microsatellite instability and the transforming growth factor-beta receptor type II gene mutation in sporadic breast cancer and their correlation with clinicopathological features.

To determine the incidence of microsatellite instability (MSI) and its relationship with both clinicopathologic parameters and patient survival, 101 cases of breast cancer were investigated. In addition, transforming growth factor-beta (TGF-beta) receptor type II (RII) gene mutation was also examined to clarify the relation to MSI in breast cancer development. MSI and RII gene mutation were screened by single strand conformation polymorphism (SSCP). The mutations of the RII gene were confirmed by a direct sequence. An association between the MSI status and the clinicopathological features was examined to assess the potential of the MSI status as a prognostic indicator in sporadic breast cancer cases. MSI was detected in 12 of 101 (11.9%) breast cancer cases. The positive MSI breast cancer cases showed relatively more advanced disease than negative MSI cases, and also exhibited relatively poorer prognoses. No RII gene mutations were observed in any of the breast cancer cases. Our data suggest that the MSI status may thus be a useful indicator for the prognosis of sporadic breast cancer cases. However, the breast seems to be an infrequent target organ for cancer development through RII gene mutations. As a result, tumor progression through this pathway appears to be related to organ specificity. For positive MSI breast cancers, other target genes therefore still need to be identified.

Breast Neoplasms↗
PubMed1999

Microsatellite instability in double cancers of the esophagus and head and neck.

It is generally accepted that patients with squamous cancers of the esophagus are known to have a high risk of concomitant head and neck cancer. However, there have been only a few reports describing microsatellite instability (MSI) in patients with both esophageal squamous cell carcinoma and head and neck cancers. To evaluate the role of genetic instability in carcinogenesis in such patients, we analyzed six microsatellite loci in 21 tumors from 10 patients who had developed primary cancers of both the esophagus and the head and neck. MSI was detected in 6 out of 10 patients. In five patients with double cancer, MSI was observed at the same microsatellite loci in both the esophageal and the head and neck tumors obtained from the same individuals. These data suggest that such patients may have the same underlying defect in the mismatch repair system, providing insight into possible mechanisms for field carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed1999

A 127-kDa protein (UV-DDB) binds to the cytoplasmic domain of the Alzheimer's amyloid precursor protein.

Alzheimer amyloid precursor protein (APP) is an integral membrane protein with a short cytoplasmic domain of 47 amino acids. It is hoped that identification of proteins that interact with the cytoplasmic domain will provide new insights into the physiological function of APP and, in turn, into the pathogenesis of Alzheimer's disease. To identify proteins that interact with the cytoplasmic domain of APP, we employed affinity chromatography using an immobilized synthetic peptide corresponding to residues 645-694 of APP695 and identified a protein of approximately 130 kDa in rat brain cytosol. Amino acid sequencing of the protein revealed the protein to be a rat homologue of monkey UV-DDB (UV-damaged DNA-binding protein, calculated molecular mass of 127 kDa). UV-DDB/p127 co-immunoprecipitated with APP using an anti-APP antibody from PC12 cell lysates. APP also co-immunoprecipitated with UV-DDB/p127 using an anti-UV-DDB/p127 antibody. These results indicate that UV-DDB/p127, which is present in the cytosolic fraction, forms a complex with APP through its cytoplasmic domain. In vitro binding experiments using a glutathione S-transferase-APP cytoplasmic domain fusion protein and several mutants indicated that the YENPTY motif within the APP cytoplasmic domain, which is important in the internalization of APP and amyloid beta protein secretion, may be involved in the interaction between UV-DDB/p127 and APP.

Alzheimer Disease↗
PubMed1999

Effects of a novel calcium antagonist, benidipine hydrochloride, on platelet responsiveness to mental stress in patients with essential hypertension.

The effects of a novel calcium antagonist, benidipine hydrochloride, on responses of platelets to mental stress were evaluated in nine patients with essential hypertension. Before and 12 weeks after the monotherapy with benidipine (2-4 mg/day), platelet aggregability and plasma beta-thromboglobulin were determined during rest and after a 10-min arithmetic stress. Before the treatment, arithmetic stress significantly increased platelet aggregability in response to adenosine diphosphate (ADP) and plasma beta-thromboglobulin level. Blood pressure, pulse rate, and plasma catecholamines also increased during arithmetic stress. The treatment with benidipine did not affect resting values of platelet functions, but attenuated significantly stress-induced alterations in primary aggregation to 1.0 microM ADP (34 +/- 4% to 40 +/- 3% before treatment vs. 32 +/- 2% to 34 +/- 3% after benidipine), ADP threshold for biphasic aggregation (2.2 +/- 0.4 to 1.8 +/- 0.3 microM before treatment vs. 2.2 +/- 0.3 to 2.2 +/- 0.4 microM after benidipine) and plasma beta-thromboglobulin level (74 +/- 16 to 104 +/- 15 ng/ml before treatment vs. 60 +/- 10 to 52 +/- 8 ng/ml after benidipine; p < 0.05 for Stress x Treatment interactions in all values). The pretreatment elevations in blood pressure and sympathetic activity with stress were not modified by benidipine treatment. In conclusion, the monotherapy with benidipine did not affect platelet function during the resting condition, but significantly suppressed the platelet activation induced by arithmetic stress in patients with essential hypertension.

Adult↗
PubMed1999

[Resuscitation from the viable but nonculturable state of Helicobacter pylori].

It is well known that the change of state from the culturable to not culturable on pathogenic organisms could easily occurred. These states of bacteria were so called viable but nonculturable (VNC). The coccoid form of H. pylori is seems to be in this state. The possibility of resuscitation of H. pylori was examined in vitro. The coccoid form bacteria was treated with Ammonium Sulfate and heat shock before culture, and cultured in Brucella broth containing, sodium pyruvate, laked human erythrocyte and serum. The growth of the rod spiral form was found in the coccoid form bacteria, and further the bacteria could grow on blood agar and Skirrow agar as well as the original strain. It was strongly suggested that the resuscitation from VNC state of cells to culturable form consists of two processes, stimulation and supplemented of appropriate nutrition.

Bacteriological Techniques↗
PubMed1999

Different effects of temocapril and cadralazine on electrocardiographic voltages and left ventricular mass in patients with essential hypertension.

To assess whether electrocardiographic variables are useful to detect the regression of left ventricular (LV) mass after long-term antihypertensive treatment, we related electrocardiographic voltages to echocardiographic variables before and after treatment with an ACE inhibitor, temocapril (TEM), or direct vasodilator, cadralazine (CAD). Twenty-one patients with essential hypertension were treated with either TEM (n = 11) or CAD (n = 10) for one year. LV mass index (LVMI) by echocardiography and Sokolow-Lyon voltage (SV1 + RV5), Cornell voltage (RaVL + SV3) and RV5 + RV6 by standard 12-lead electrocardiographic voltages were determined before and after treatment. Both drugs decreased blood pressure to the same extent. Both Sokolow-Lyon voltage and RV5 + RV6 tended to decrease in the ACE group (40.0 +/- 9.4 to 37.2 +/- 9.4 mm and 44.7 +/- 13.5 to 41.7 +/- 11.7 mm, respectively, N.S.), but not in the CAD group (38.4 +/- 6.8 to 39.7 +/- 7.7 mm and 42.9 +/- 10.4 to 46.8 +/- 11.2 mm, respectively, N.S.). LVMI decreased in the ACE group (-24 +/- 22 g/m2), whereas it increased in the CAD group (37 +/- 27 g/m2, p < 0.01). Change in LVMI was correlated with the changes in RV5 + RV6 and Sokolow-Lyon voltage (r = 0.73, p < 0.01 and r = 0.70, p < 0.01, respectively), but not with that in Cornell voltage. These results indicated that the changes in voltage criteria of RV5 + RV6 and Sokolow-Lyon are useful to assess the change in LVM after antihypertensive treatment in patients with essential hypertension although voltage variables in electrocardiogram were not sensitive to detect changes in LVMI.

Aged↗
PubMed1999

Association between a focal spared area in the fatty liver and intrahepatic efferent blood flow from the gallbladder wall: evaluation with color Doppler sonography.

OBJECTIVE: The purpose of this study was to investigate whether fatty sparing adjacent to the gallbladder fossa is related to efferent blood flow from the gallbladder wall. SUBJECTS AND METHODS: Color and power Doppler sonography were performed in 80 patients with a fatty liver that appeared as a fine echogenic pattern with considerable deep attenuation on sonography. We analyzed whether color signal appeared around the spared area, the gallbladder wall, or both. Subsequently, when such signal was detected, pulse Doppler analysis of the signal was performed. RESULTS: Color signal indicating efferent blood flow from the gallbladder wall was detected in 25 (64%) of 39 patients with a focal spared area at the gallbladder fossa and in two (5%) of 41 patients without a focal spared area. This difference was statistically significant (p < .05). The waveform of efferent blood flow signals (n = 25) that were seen within spared areas was continuous in 23 (92%) of 25 patients and was pulsatile in the remaining two patients (8%). CONCLUSION: Blood flow from the gallbladder wall to areas of the spared liver was frequently revealed by color and power Doppler sonography; therefore, this blood flow may be associated with focal fatty sparing.

Adult↗
PubMed1999

[Genetic alterations in human malignant tumor].

To clarify the genetic background of cancer patients, microsatellite instability (MSI) and mutations of transforming growth factor-beta type II receptor (RII), p53 and k-ras gene were investigated. MSI were detected in 33.3% of esophageal, 15.8% of gastric, 21.4% of colorectal, 4.5% of bile duct, 0% of gallbladder, 13.3% of pancreatic, 11.6% of breast and 10.5% of thyroid cancers. Mutations of RII gene were detected in only 2 of 9 MSI-positive colorectal cancers. k-ras gene mutations were investigated in colorectal, bile duct, gallbladder, breast and thyroid cancer and were detected in 11.9%, 36.4%, 64.3%, 0%, 0% of each. p53 gene mutations were investigated in colorectal and breast cancer and were detected in 9.5% and 9.3%, respectively. In addition, 4 colorectal cancer cases exhibited more than two kinds of genetic alteration, while breast cancer cases showed only single kind. From these findings, it is suggested that 1) the incidence of each genetic alteration differed among the cancers investigated and organ specificity may exist; 2) the genetic alterations investigated here contributed to a minor part of cancer development, which requires the identification of more unknown genes related to carcinogenesis; 3) to clarify the molecular mechanism of cancer development, the genetic alterations including genomic instability and mutations of several kinds of genes related to cancer development in each case should also be determined along with their genetic molecular profile.

Genes, p53↗
PubMed1999

[Annual change of the pet in allergic patients home for ten years].

There are only few paper in Japan which reports the prevalence of pet keepers in the allergic population and also of the type of pets they keep. We made investigation on these points in 1337 allergic patients employing a questionnaire. Among 1337 patients, allergic conjunctivitis patients were found in 67, eczema patients in 118, allergic rhinitis patients in 368 and bronchial asthmatic patients in 1043. These number contained those who overlapped in symptoms. Approximately 43% of allergy patients are currently keeping the pet at present while 11.2% of the patient had kept the pet in the past. There were two peaks in the age when they began to keep a pet, 6 to 12 and 30 to 40 years of age. Trend in the past decade showed that both the dog and cat bred in foreign countries were increasing. About 80% of patients who own the foreign bred dogs keep them indoor. This ratio is increasing gradually. Another conspicuous change is the sharp increase in those who keep hamsters which occupied 20% of all the pet keeper in 1997. Percentages of the patient who recognizes the aggravation of their symptoms in eye, nose, skin and also as asthma often pet keeping is a about 10%. One out of 4 patients who keep the pet has a family member with rhinitis and/or asthma. We concluded that too many of the allergic patients keep the pet against their benefit and they must be informed that the pet could be the cause of allergy symptoms.

Adult↗
PubMed1999

Semi-quantitative procedure for telomeric repeat amplification protocol (TRAP) assay in colorectal carcinomas.

Telomerase activity is intensively studied as a prognostic marker in malignancies, and generally detected by telomeric repeat amplification protocol (TRAP) assay. Recently, Ohyashiki et al. demonstrated a semi-quantitative procedure for TRAP assay, which is more useful than the qualitative one to analyze the correlation between telomerase activity and clinicopathological features in carcinomas. Therefore, we used semi-quantitative TRAP assay to analyze the correlation between telomerase activity and clinicopathological factors in colorectal carcinomas. Twenty-nine cases of advanced colorectal carcinoma, obtained by surgery, were studied. A telomerase detection kit, TRAP-eze, was used for the PCR based TRAP assay, and a DNA sequencer for a semi-quantitative analysis was used for a analysis. Telomerase activity was positively detected in all samples, and its mean value was 2.076+/-1.634 units (range; 0.536-8.932 units). Based on Dukes' classification, the activity tended to be higher in Dukes' A (2.722 units; P = 0.0525) and C (2.430 units) than in Dukes' B (1.552 units). The activity was higher in the right colon than at other locations. (right vs. left, rectum = 3.167 vs. 1.216 units; P<0.05, 1.604 units; P<0.01). The activity was higher in poorly differentiated adenocarcinoma than in well differentiated adenocarcinoma (3.743 vs. 1.491 units; P<0.05). Semi-quantitative TRAP assay is useful to analyze the correlation between telomerase activity and clinicopathological factors in colorectal carcinomas.

Aged↗
PubMed1998

DPM2 regulates biosynthesis of dolichol phosphate-mannose in mammalian cells: correct subcellular localization and stabilization of DPM1, and binding of dolichol phosphate.

Biosynthesis of glycosylphosphatidylinositol and N-glycan precursor is dependent upon a mannosyl donor, dolichol phosphate-mannose (DPM). The Thy-1negative class E mutant of mouse lymphoma and Lec15 mutant Chinese hamster ovary (CHO) cells are incapable of DPM synthesis. The class E mutant is defective in the DPM1 gene which encodes a mammalian homologue of Saccharomyces cerevisiae Dpm1p that is a DPM synthase, whereas Lec15 is a different mutant, indicating that mammalian DPM1 is not sufficient for DPM synthesis. Here we report expression cloning of a new gene, DPM2, which is defective in Lec15 cells. DPM2, an 84 amino acid membrane protein expressed in the endoplasmic reticulum (ER), makes a complex with DPM1 that is essential for the ER localization and stable expression of DPM1. Moreover, DPM2 enhances binding of dolichol phosphate, a substrate of DPM synthase. Mammalian DPM1 is catalytic because a fusion protein of DPM1 that was stably expressed in the ER synthesized DPM without DPM2. Therefore, biosynthesis of DPM in mammalian cells is regulated by DPM2.

Amino Acid Sequence↗
PubMed1998

A basic amino acid in the cytoplasmic domain of Alzheimer's beta-amyloid precursor protein (APP) is essential for cleavage of APP at the alpha-site.

In Alzheimer's disease (AD), the beta-amyloid peptide (Abeta) is thought to be produced as a result of the aberrant metabolism of beta-amyloid precursor protein (APP). We report that the APP cytoplasmic domain contains a novel and important signal for APP metabolism. A single amino acid mutation that changed arginine at amino acid 747 of APP770 (corresponding to position 672 of APP695) to a non-basic amino acid greatly increased the production of intracellular APP carboxyl-terminal fragment(s) cleaved at beta-site(s) (CTFbeta), but did not result in increased secretion of Abeta40 and Abeta42. This was not due to a simple intracellular accumulation of CTFbeta resulting from a lack of gamma-secretase. CTFbeta derived from this mutant APP was generated and degraded as efficiently as CTFbeta derived from wild-type APP. This result indicates that the increase in the quantity of CTFbeta does not always give rise to more Abeta production, as was previously suggested by studies of a familial AD mutation of APP. These findings suggest that APP carrying the substitution mutation at this basic amino acid may be metabolized by another protein secretory pathway. Although these results have not completely elucidated why CTFbeta derived from the mutant APP escapes from subsequent cleavage by gamma-secretase, analysis of the processing pathway of this mutant APP should provide insights into the pathogenesis of the sporadic type of AD.

Alanine↗