Search PubMed⌕ Search

Biomedical subjects

H Shibuya

Publications and source records attributed to H Shibuya.

At least 235 records · Page 13Linked to original sources
PubMed1995

Squamous cell carcinoma of the oral cavity: MR findings and value of T1-versus T2-weighted fast spin-echo images.

OBJECTIVE: The purposes of this study were to describe the characteristics of squamous cell carcinomas of the oral cavity on unenhanced and contrast-enhanced T1-weighted spin-echo (SE) MR images and unenhanced T2-weighted fast spin-echo (FSE) MR images and to determine which sequences best delineate the margins and extent of the tumors. MATERIALS AND METHODS: Forty-four patients with proved squamous cell carcinoma of the oral cavity (tongue, 24; floor of mouth, seven; buccal mucosa, four; maxillary gingiva, two; and mandibular gingiva, seven) underwent unenhanced axial T2-weighted FSE MR imaging and unenhanced and enhanced axial and coronal T1-weighted SE MR imaging. The appearance, signal characteristics, and extent of the tumors were assessed, and the delineation of tumor margins with each sequence or combination of sequences was evaluated by use of a grading system ranging from 1 (poor) to 3 (excellent). Three patients were excluded because of artifacts on the MR images caused by dental restorations. RESULTS: Tumors in all 41 patients were depicted on unenhanced T1-weighted SE images, but in four patients, tumors were not visible on T2-weighted FSE images. Except for tumors that invaded the maxillary gingiva, the tumors generally had homogeneous, low signal intensity on unenhanced T1-weighted images and nonhomogeneous, high signal intensity on T2-weighted FSE images. All tumors showed enhancement, 76% with a nonhomogeneous appearance. The delineation of tumor margins was excellent (grade 3) in 31 cases and fair (grade 2) in 10 cases. The highest rating was given for unenhanced T1-weighted images in 10 cases, for contrast-enhanced T1-weighted images in 10 cases, for the combination of both unenhanced and contrast-enhanced T1-weighted images in 18 cases, for the combination of unenhanced T1-weighted and T2-weighted FSE images in five cases, and for T2-weighted FSE images in one case. In three cases, the highest rating was given for both combinations of pulse sequences. CONCLUSION: An unenhanced T1-weighted sequence should be used as the basic pulse sequence for MR imaging of tumors of the oral cavity. When tumor margins are not clearly delineated with this sequence, T2-weighted FSE and contrast-enhanced T1-weighted sequences should be added. Although both of these sequences provide supplementary information, the contrast-enhanced T1-weighted sequence is more useful in delineating the margins and extent of tumors than is the T2-weighted FSE sequence.

Adult↗
PubMed1995

[Epstein-Barr virus associated natural killer cell leukemia: report of an autopsy case].

A 20-year-old female was admitted because of high fever, hepatosplenomegaly, severe hepatic dysfunction and coagulopathy. Peripheral blood showed pancytopenia and granular lymphocytes bearing the natural killer cell phenotype (CD2+CD3-CD16+CD56+CD57-TCR alpha beta-TCR gamma delta-) constituted 97% of leucocytes. Southern blot analysis of DNA obtained from peripheral blood mononuclear cells showed germ-line configuration of TCR beta, gamma and delta chain genes. EBV-DNA was detected in a single episomal form by using EBV-terminal repeat probe. Bone marrow findings were consistent with hemophagocytic syndrome and administration of VP-16 was effective transiently. After ten months she died from massive gastrointestinal bleeding. An in situ hybridization study identified EBV-RNA (EBER-1) in atypical lymphocytes infiltrating bone marrow, spleen and lymph nodes. Sections of liver showed steatosis and infiltration of T cells (CD3+ and EBER-1-negative) in the portal areas and few atypical lymphocytes in sinusoids. The patients developed an EBV-associated clonal proliferation of natural killer (NK) cells, but the clinical features were suggestive of chronic active EBV infection or virus-associated hemophagocytic syndrome (VAHS) rather than leukemia. Bone marrow transplantation for NK cell leukemia is an issue to be discussed.

Adult↗
PubMed1994

The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy.

BACKGROUND: Male patients with oral and oropharyngeal cancer are known to have high risk of concomitant esophageal cancer developing. Thus, mass screening programs are pursued to detect such esophageal cancer early, and in a mass screening trial of patients with early oral and oropharyngeal cancer, the efficacy of Lugol dye endoscopy for detecting concomitant esophageal cancers has been evaluated. METHODS: Lugol dye was used in an endoscopic screening of 101 patients with oral cancer and 26 with oropharyngeal cancer; all of the patients were men. RESULTS: Among these 127 patients, eight (6.3%) clinical asymptomatic concomitant esophageal cancers were detected, and four of these eight cancers were found in the patients with oropharyngeal cancer. Five of these eight superficial lesions could not be detected by ordinary endoscopy or barium study. CONCLUSION: Our results show that Lugol dye endoscopy is indispensable for monitoring male patients with oral or oropharyngeal cancer to detect an early concomitant esophageal cancer. In addition, a higher frequency of concomitant esophageal cancer was seen in the patients with oropharyngeal cancer than in the patients with oral cancer.

Adult↗
PubMed1994

[Z-100 as radiation mucositis protector in head and neck tumor management].

To study the radioprotective effect of Z-100 against mucositis, twenty-five patients with head and neck malignancies were received external irradiation of 30-61.2 Gy (mean 44.4 Gy) concurrent with Z-100 injection twice a week. Of these cases, an incidence of dysphagia was less than 20% and white coating mucositis below 50%. Frequency of radiation mucositis in these regions was reduced compared to our previous experiences; efficacy of 88%. This combined therapy seems to be a promising method.

Adult↗
PubMed1994

Rapid fluorometric assay for mitochondrial proton adenosine triphosphatase activity for assessment of viability of liver graft tissue.

We developed an improved determination method of mitochondrial proton adenosine triphosphatase (ATPase) activity in the liver. The activity was measured fluorometrically with a 3,3'-dipropylthiodicarbocyanine iodide (diS-C3(5)), which is excited at 625 nm and emits fluorescence at 670 nm. This dye transmits the electric potential across the inner mitochondrial membrane. The fluorescence intensity of diS-C3(5) with mitochondria (100 microliters, 4-16 mg/ml protein) in a 2 ml potassium buffer (pH 7.4) was regarded as a standard electric potential. After confirming the activity of the mitochondrial electron transport chain by succinic acid (9 mumol), we inhibited the chain by antimycin A (1.25 micrograms). Fluorescence intensity decreased by adenosine 5'-triphosphate (ATP) (2 mumol) and oligomycin (25 micrograms) inhibited this depression. The value of mitochondrial proton ATPase activity was calculated as a percentage of the fluorescence intensity change by ATP per the standard electric potential. The activity of mitochondrial proton ATPase in the normal fresh rat livers was 50.3 +/- 2.2%. Good correlation (r2 = 0.807) between two methods for mitochondrial proton ATPase activity, our newly developed method and a conventional colorimetric method, was obtained in the rat livers with various conditions. This method has advantages that the proton ATPase activity can be measured in intact mitochondria, and all procedures can be completed within 40 min. It is suitable for the determination of mitochondrial viability of liver graft in the hepatic resections and transplantations.

Adenosine Triphosphate↗
PubMed1994

Effect of a single injection of psychoactive drugs on CCK mRNA in rat brain.

The acute and long-term effects of a single injection of psychoactive drugs, methamphetamine or phencyclidine, were investigated by Northern blot to assess alterations in the cholecystokinin (CCK) mRNA in three areas of the rat brain. In the frontal cortex, there were no significant changes in CCK mRNA after the drug injection. In contrast, decreases in CCK mRNA were observed in the posterior cortex and the hippocampus from 30 min to 48 h after the drug treatment. The data suggest that CCK gene expression has different sensitivity to these psychoactive drugs within the cortices.

Animals↗
PubMed1994

The use of CT and scintigraphy in diagnosing a cystic ameloblastoma of the jaw.

The results of CT and bone scintigraphy of eight patients with a histologically proven cystic ameloblastoma of the jaw are reviewed. CT imaging revealed unilocular and multilocular cystic lesions with well-defined thin cystic borders in all patients. CT also detected increased density in the bone marrow adjacent to the cystic radiolucent lesion, suggesting that the ameloblastoma had spread into the cancellous bone. Further, nuclear bone scans showed a doughnut-shaped pattern in all cases and radioactivity beyond the cystic wall, indicating intramedullary extension of the ameloblastoma. The use of these two modalities was found to be complementary in delineating the full nature and extent of the pathologic lesion.

Adult↗
PubMed1994

Efficacy of twice-daily cimetidine in pediatric peptic ulcer.

The clinical efficacy of twice-daily cimetidine (20 mg/kg/day) was retrospectively studied in 19 children with gastric ulcer (GU) and 23 with duodenal ulcer (DU) in the active stage. Endoscopically confirmed cumulative healing rates at 2, 4, and 8 weeks of treatment were 53.5, 73.7, and 94.7% in the GU group and 15.4, 50.0, and 87.0% in the DU group, respectively. There was no significant difference between the groups at each time point. The mean period of time until complete disappearance of symptoms in the GU and DU groups was 3.5 +/- 2.6 and 4.2 +/- 3.3 days, respectively (NS). With regard to symptoms, abdominal tenderness rather than spontaneous pain appeared to be a better indicator of ulcer healing. Ulcer recurrence was found endoscopically during follow-up in 2 of 13 GU patients (15.4%) and 11 of 19 DU patients (57.9%); thus, the cumulative recurrence rate of the DU group was higher than that of the GU group (p < 0.05). No adverse effects related to cimetidine were demonstrated during treatment or short-term follow-up. We conclude that twice-daily cimetidine at a dosage of 20 mg/kg/day is as effective for the symptomatic improvement and healing of peptic ulcer as the conventional three- or four-times-daily regimens. The optimal dosage of cimetidine requires further study.

Adolescent↗
PubMed1994

Gas gangrene following sacral pressure sores.

We report two cases of gas gangrene developed from sacral pressure sores. The first case was clostridial and the second, non-clostridial gas gangrene. Both patients died within two months. The first patient, a 56-year-old woman suffering from palsy of the lower half of the body for 3 weeks, developed a sacral pressure sore. One month later, crepitus by palpation and gas formation in the X-ray film were detected in the hip and right thigh. A culture of odoriferous pus yielded Clostridium limosum in addition to Staphylococcus intermedius, Enterococcus faecalis, Pseudomonas aeruginosa, and Bacteroides fragilis. Blood culture yielded Bacteroides fragilis. The patient died 50 days after admission in spite of surgical debridement and aggressive therapy with high doses of antibiotics and hyperbaric oxygen. The second patient, a 70-year-old man suffering from diabetic nephropathy, arteriosclerosis obliterans of the lower limbs, and cerebral infarction, developed a large decubitus ulcer covering the whole sacral area. Crepitus and gas were detected in the soft tissue of the left gluteal region. Almost the entire gluteus maximus muscle was necrotic. Bacteroides fragilis, methicillin-resistant or -sensitive Staphylococcus aureus and Escherichia coli were isolated from the muscle. Bacteroides fragilis was also obtained by blood culture. The patient died on the 72nd day after admission.

Aged↗
PubMed1994

Functional dissection of p56lck, a protein tyrosine kinase which mediates interleukin-2-induced activation of the c-fos gene.

Members of the newly identified receptor family for cytokines characteristically lack the intrinsic protein tyrosine kinase domain that is a hallmark of other growth factor receptors. Instead, accumulating evidence suggests that these receptors utilize nonreceptor-type protein tyrosine kinases for downstream signal transduction by cytokines. We have shown previously that the interleukin-2 receptor beta-chain interacts both physically and functionally with a Src family member, p56lck, and that p56lck activation leads to induction of the c-fos gene. However, the mechanism linking p56lck activation with c-fos induction remains unelucidated. In the present study, we systematically examined the extent of c-fos promoter activation by expression of a series of p56lck mutants, using a transient cotransfection assay. The results define a set of the essential amino acid residues that regulate p56lck induction of the c-fos promoter. We also provide evidence that the serum-responsive element and sis-inducible element are both targets through which p56lck controls c-fos gene activation.

Base Sequence↗
PubMed1994

Indonesian medicinal plants. VII. Seven new clerodane-type diterpenoids, peronemins A2, A3, B1, B2, B3, C1, and D1, from the leaves of Peronema canescens (Verbenaceae).

Seven new clerodane-type diterpenoids, named peronemins B2 (1), A2 (2), B1 (3), C1 (4), B3 (5), A3 (6), and D1 (7), were isolated from the leaves of Peronema canescens (Verbenaceae), an Indonesian medicinal plant collected in Bengkulu, Sumatera Island, Indonesia. The chemical structures of 1-7 have been elucidated on the basis of their chemical and physicochemical properties.

Diterpenes↗
PubMed1994

Indonesian medicinal plants. VIII. Chemical structures of three new triterpenoids, bruceajavanin A, dihydrobruceajavanin A, and bruceajavanin B, and a new alkaloidal glycoside, bruceacanthinoside, from the stems of Brucea javanica (Simaroubaceae).

Three new apotirucallane-type triterpenoids named bruceajavanin A (1) dihydrobruceajavanin A (2) and bruceajavanin B (3), and a novel beta-carboline alkaloidal glycoside named bruceacanthinoside (4) were isolated from the stems of Brucea javanica (Simaroubaceae), a traditional medicine used to treat malaria in the Bengkulu area, Sumatra, Indonesia. Their chemical structures have been elucidated on the bases of their chemical and physicochemical properties. Bruceajavanin A (1), dihydrobruceajavanin A (2) and bruceacanthinoside (4) were shown to inhibit growth of the cultured malarial parasite Plasmodium falciparum K1 of a chloroquine-resistant strain.

Animals↗
PubMed1994

Indonesian medicinal plants. IX. Chemical structures of gongganosides A, B, and C, three new quinovic acid glycosides from the bark of Bhesa paniculata (Celastraceae).

Three new quinovic acid glycosides, named gongganosides A (1), B (2), and C (3), were isolated from the bark of Bhesa paniculata (Celastraceae), an Indonesian medicinal plant collected in Sumatra Island. The chemical structures have been elucidated on the basis of chemical and physicochemical evidence as quinovic acid 3-O-beta-D-xylopyranosyl(1-->3)-alpha-L- rhamnopyranoside for 1,28-O-beta-D-glucopyranosylquinovic acid 3-O-alpha-L-rhamnopyranoside for 2, and 28-O-beta-D-glucopyranosyl-quinovic acid 3-O-beta-D-xylopyranosyl(1-->3)-alpha-L-rhamnopyranoside for 3.

Carbohydrate Sequence↗
PubMed1994

Indonesian medicinal plants. X. Chemical structures of four new triterpene-glycosides, gongganosides D, E, F, and G, and two secoiridoid-glucosides from the bark of Bhesa paniculata (Celastraceae).

Four new triterpene-glycosides, named gongganosides D (4), E (5), F (6), and G (7), and two new secoiridoid-glucosides, (7R)-7-caffeoyloxysweroside (8) and (7S)-7-caffeoyloxysweroside (9), were isolated from the bark of the Indonesian medicinal plant Bhesa paniculata (Celastraceae). The chemical structures have been elucidated on the bases of their chemical and physiocochemical properties.

Carbohydrate Sequence↗
PubMed1994

Chemical transformation of terpenoids. X. Ionophoretic activities of macrocyclic lactone epoxides synthesized from geraniol.

Two coronand-type 18-membered lactone epoxides, i.e., geranyl dimeric lactone diepoxide (GL2E2, 10) and tetraepoxide (GL2E4, 11), were synthesized from geraniol as diastereomeric mixtures. Among them, GL2E4 (11) was shown to exhibit ion-transport activity for Ca2+ ion in the test using a W-07 (liquid-membrane type) apparatus and ion-permeation activities for Ca2+ and K+ ions across the human erythrocyte membrane. Isolation of six component diastereomers of GL2E4 (11) [GL2E4-1 (11c), -2 (11d), -3 (11e), -4 (11f), -5 (11g), -6 (11h)], was effected by HPLC separation of two diastereomeric tetraepoxides (11a, 11b) which were prepared from two diepoxides (GL2E2-1, 10a and GL2E2-2, 10b). The relative stereostructures of these diastereomers were determined by a combination of X-ray diffraction and 1H-NMR analyses. Among the six diastereomers, S2-symmetrical GL2E4-4 (11f) exhibited the strongest ion-transport activity for Ca2+ ion while C2-symmetrical GL2E4-6 (11h) exhibited the strongest ion-permeation activity for Ca2+ ion across the human erythrocyte membrane.

Acyclic Monoterpenes↗