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Biomedical subjects

H Tsuchiya

Publications and source records attributed to H Tsuchiya.

At least 91 records · Page 5Linked to original sources
PubMed1997

Total en bloc spondylectomy. A new surgical technique for primary malignant vertebral tumors.

STUDY DESIGN: The study of seven patients with primary malignant or benign aggressive tumors who underwent a new aggressive surgical technique termed "total en bloc spondylectomy" is reported. OBJECTIVES: To report a new surgical technique of total en bloc spondylectomy for complete, resection of primary spinal malignancy and for oncologic curability. SUMMARY OF BACKGROUND DATA: The conventional approach for primary spinal malignancy is via intralesional piecemeal resection, and very few reports have described en bloc extralesional resectioning with histopathologically wide or marginal surgical margins. METHODS: Total en bloc spondylectomy, consisting of en bloc laminectomy and en bloc corpectomy followed by anterior instrumentation with spacer grafting and posterior spinal instrumentation, was performed in five patients with primary malignant tumors and two patients with giant cell tumors. Patients were observed for 2 years to 6.5 years, except for one patient who died 7 months after surgery because of a mediastinal metastasis. RESULTS: All patients, except one, attained significant clinical improvement after surgery with no major complications. Histologically, the margins were wide or marginal except for the pedicles, and occasionally the spinal canal and the posterior, where they were accepted to be intralesional. One patient died of metastasis that was not directly related to surgery itself. There was no local recurrence. CONCLUSIONS: The advantages of total en bloc spondylectomy include resection of the involved vertebra(e) in two major blocs, rather than in a piecemeal pattern, and completion of the procedure during one surgical session posteriorly. The "total en bloc spondylectomy" offers one of the most aggressive modes of therapy for primary spinal malignancy.

Adolescent↗
PubMed1997

Blockage of mesenteric lymphatic flow in rats.

An experimental model of blockage of the mesenteric lymphatic flow (MLF) in rats was designed, and morphologic changes of mesenteric lymphatic vessels (MLV) and lymph nodes were investigated by mesenteric lymphangiography and histopathologic examination. Body weight in rats with blockage of MLF did not increase normally. Mesenteric lymphangiography revealed dilation of the MLV, reverse flow into the peripheral MLV, and leakage of contrast medium, resulting in chylous ascites. Remarkable dilation of the lymphatic sinuses and dilated and increased rough endoplasmic reticulum in lymphocytes in the mesenteric lymph nodes due to lymph stagnation were observed by light and electron microscopic examination, respectively.

Animals↗
PubMed1997

Childhood bronchial mucoepidermoid tumors.

A very rare case of a childhood bronchial mucoepidermoid tumor is presented. A 4-year-old girl was hospitalized with prolonged pneumonia. Computed tomography of the chest showed a tumor with calcifications in the right upper lobe. Subsequently, the patient underwent right upper lobectomy. Histologically, the tumor was a low-grade mucoepidermoid tumor originating from the bronchus. Three years postoperatively there has been no evidence of disease. A review of the literature indicates that 30 cases of bronchial mucoepidermoid tumors in children have been reported. Symptoms result from associated bronchial obstruction. Children with recurrent or prolonged pneumonia should undergo aggressive diagnostic investigation by chest tomography or bronchoscopy. Appropriate therapy for childhood bronchial mucoepidermoid tumor is total resection of the lesion while sacrificing as little of the normal lung tissue as possible.

Airway Obstruction↗
PubMed1997

Vitamin C and copper interactions in guinea-pigs and a study of collagen cross-links.

The purpose of this study was, first to explore metabolic interactions between Cu and ascorbic acid in guinea-pigs, particularly with respect to any possible disadvantages of high ascorbate in the presence of low Cu intakes, and second, to test the hypothesis that variations in ascorbate and/or Cu status might influence collagen cross-linking, either by inducing a change in the crosslinks: hydroxyproline ratio, or by inducing a change in the pyridinoline: deoxypyridinoline crosslinks ratio. Four matched groups, each of eight male weanling Dunkin-Hartley guinea-pigs, were maintained on purified diets containing either no added Cu, or 150 mg Cu/kg diet, and either 0.1 g or 30 g ascorbic acid/kg diet. They were then killed 8 weeks later, and the following indices were measured: body and organ weights; blood haemoglobin; adrenal ascorbate concentrations; Cu concentrations in plasma, liver and femur; superoxide dismutase (EC 1.15.1.1) activity in whole blood and liver; hydroxyproline, pyridinoline and deoxypridinoline in femur and in urine. The principal observations were: Cu intake significantly affected blood and tissue Cu concentrations and superoxide dismutase activity; and ascorbic acid intake significantly affected adrenal ascorbate levels and the deoxypyridinoline: pyridinoline cross-links ratio, especially in bone (femur). There was evidence of a significant interaction between ascorbate and Cu with respect to adrenal and plasma Cu concentrations, blood superoxide dismutase activity and body weights. We conclude that interactions between ascorbate and Cu at the functional level were present but modest, and that a new and potentially powerful functional index of ascorbate status may exist within the deoxypyridinoline:pyridinoline collagen cross-link ratio.

Adrenal Glands↗
PubMed1997

Thallium-201 SPECT in differentiating bone infarction from metastatic lesions in osteosarcoma.

The authors present a case of bone infarction in the proximal epiphysis of the right tibia, which was caused by preoperative intraarterial chemotherapy for osteosarcoma. MR imaging revealed that suspected metastases had inhomogeneous signal intensity similar to that of the primary tumor, which made a metastatic lesion difficult to exclude. On TI-201 SPECT, no accumulation was found in the lesions, confirming that they were not osseous metastases. Consequently, this enabled limb salvage surgery to be performed with joint preservation. Intraoperative biopsy revealed no viable tumor cells in the lesion, and bone infarction was suspected. TI-201 SPECT was very useful, not only in differentiating bone infarction from tumor progression, including metastatic lesions, but also in the determination of the operative technique.

Adolescent↗
PubMed1997

Growth inhibition of oral bacteria related to denture stomatitis by anti-candidal chalcones.

In the antimicrobial therapy of denture stomatitis, it is desirable to inhibit the growth of not only the primary causative organism, Candida albicans, but also other oral bacteria closely associated with the condition. Three synthetic anti-candidal chalcones were characterized and compared for their additional activity in inhibiting these causative bacteria. Among the tested chalcones, 2,4,2'-trihydroxy-5'-methylchalcone showed the highest activity for different Gram-positive bacteria. It inhibited the growth of streptococci, staphylococci and lactobacilli at 25.0-50.0 micrograms/mL which was lower than or comparable to its minimum inhibitory concentration for candida. It functioned with a bactericidal action and leaked 260 nm-absorbing substances from the streptococcal cells. The antimicrobial activity of 2,4,2'-trihydroxy-5'-methylchalcone against both primary and secondary causative agents suggests it could be useful as a potent therapeutic agent in denture stomatitis.

Anti-Bacterial Agents↗
PubMed1997

Limb salvage using distraction osteogenesis. A classification of the technique.

We report the results of distraction osteogenesis (callotasis) for the reconstruction of extensive defects after the excision of skeletal tumours in the limbs. Bone transport was performed in ten patients (five osteosarcomas and five giant-cell tumours), shortening-distraction in three (two osteosarcomas and one Ewing's sarcoma), and distraction osteogenesis combined with an intramedullary nail to reduce the time of external fixation in six (three osteosarcomas, two chondrosarcomas, and one malignant fibrous histiocytoma). The mean length of the defects after excision of the lesion was 8.4 cm. The mean external fixation index was 39.5 days/cm for the group treated by bone transport, 34.1 days/cm for the shortening-distraction group, and 24.0 days/cm for the group treated by distraction and an intramedullary nail. Functional evaluation gave excellent results in 12 patients, good in five and fair in two. There were ten complications in 19 patients, all of which were successfully treated. We also classified reconstruction using distraction osteogenesis into five types based on the location of the defects after resection of the tumour: type 1, diaphyseal; type 2, metaphyseal; type 3, epiphyseal; type 4, subarticular reconstruction; and type 5, arthrodesis. Our results suggest that reconstruction using distraction osteogenesis provides bone which will develop sufficient biomechanical strength and durability. It is beneficial in patients with an expectation of long-term survival and in growing children.

Adolescent↗
PubMed1997

Massive autoclaved allografts and autografts for limb salvage surgery. A 1-8 year follow-up of 23 patients.

We performed 23 reconstructions with bone grafts autoclaved at 135 degrees C for 10 minutes for extensive bone defects after tumor resection. In 15 cases, the resected specimens were autoclaved and used as autografts. In 7 cases, allografts obtained from amputated extremities or cadavers were autoclaved and immediately stored at -80 degrees C prior to their use. A combination of the two was used in 1 case. The grafts were used in combination with prostheses or other forms of internal fixation. The mean follow-up was 49 (14-98) months. Incorporation of the hostgraft junction was observed radiographically after a mean of 11 (6-17) months in all cases. No recurrence due to the autoclaved bone was observed. However, 10 patients suffered complications, including infection, bone resorption, fracture and loosening of the prosthesis. In terms of Mankin's evaluation of bone grafts, 12 patients were evaluated as good or excellent. We conclude that despite the complications, autoclaved autografts and allografts are viable options for reconstruction in many countries because of the difficulty of obtaining large quantities of fresh frozen allografts.

Adolescent↗
PubMed1997

[Evaluation of bone and soft tissue lesion using 99mTc-MIBI: comparison with 201Tl and the relation to chemotherapeutic effect].

Thirty-five patients with bone and soft tissue lesions were studied with 99mTc-MIBI and 201Tl to compare the uptake of two tracers. Planar images were obtained 15 min (early image) and 3 hr (delayed image) after the injection of both tracers. Images were evaluated visually and quantitatively using uptake ratio (lesion/background). In visual analysis, 23 of 35 patients showed similar uptake of both tracers, 9 showed more intense uptake of 99mTc-MIBI than 201Tl, and 3 showed more intense uptake of 201Tl than 99mTc-MIBI on early images. On delayed images, 21 of 32 patients showed similar uptake of both tracers, 3 showed more intense uptake of 99mTc-MIBI than 201Tl, and 8 showed more intense uptake of 201Tl than 99mTc-MIBI. In quantitative analysis, similar 201Tl and 99mTc-MIBI uptake ratios were obtained on early images. On delayed images, 99mTc-MIBI uptake ratios are less than that of 201Tl, but the difference was not significant. In some cases, 99mTc-MIBI accumulation was washed out on delayed images, therefore the early image is essential to evaluate 99mTc-MIBI accumulation. In all cases with the uptake ratios less than 1.20 on delayed 99mTc-MIBI images, chemotherapy was not effective. In malignant tumors, decreased uptake of 99mTc-MIBI accumulation on delayed images may indicate that chemotherapy is not effective. Delayed 99mTc-MIBI image may be a potential marker predicting chemotherapeutic effect in malignant bone and soft tissue tumors.

Adolescent↗
PubMed1997

Evaluating benign and malignant bone and soft-tissue lesions with technetium-99m-MIBI scintigraphy.

UNLABELLED: This study compares the ability of 201TI and 99mTc-MIBI to detect and assess tumor response to chemotherapy in malignant and benign bone and soft-tissue lesions. METHODS: Forty-two patients with various bone and soft-tissue pathologies (29 malignant and 13 benign lesions) were studied with 201TI and 99mTc-MIBI. Planar 201TI scintigraphy was performed 15 min after injection of 111 MBq of 201TI. Within 1 wk of the 201TI study, radionuclide angiography with 600-740 MBq of 99mTc-MIBI was performed and planar imaging was done 15 min later. RESULTS: In visual analysis, 31 of 42 patients showed similar uptake of both tracers, 8 showed more intense uptake of 99mTc-MIBI than 201TI and 3 showed more intense uptake of 201TI than 99mTc-MIBI. In quantitative analysis, similar 201TI and 99mTc-MIBI uptake ratios were obtained (1.96 +/- 1.25 versus 1.96 +/- 1.02, respectively; p = ns). The perfusion index derived from 99mTc-MIBI radionuclide angiography was higher than 99mTc-MIBI uptake ratio (2.33 +/- 1.23 versus 1.96 +/- 1.02, respectively; p < 0.005), but correlated well with 99mTc-MIBI uptake ratio (r = 0.75). In 11 patients with malignant tumors, 201TI and 99mTc-MIBI scintigraphy was repeated after chemotherapy and the uptake of both tracers was significantly suppressed in patients with complete response confirmed by histological evaluation. In patients with complete response (n = 3), the uptake ratio of both tracers was reduced by more than 50%, whereas, less than 20% reduction of uptake ratio was observed in patients with nonresponse (n = 6). CONCLUSION: The ability of 99mTc-MIBI to detect malignant and benign bone and soft-tissue lesions and to assess tumor response to chemotherapy was comparable to that of 201TI. In addition, blood flow could be assessed by radionuclide angiography with 99mTc-MIBI. Technetium-99m-MIBI is a promising radiopharmaceutical for the evaluation of bone and soft-tissue lesions.

Abscess↗
PubMed1997

[Leukoencephalopathy probably caused by tacrolimus hydrate after stem cell transplantation in a girl with MDS 7 monosomy].

Leukoencephalopathy probably caused by tacrolimus hydrate after stem cell transplantation in a girl with MDS 7 monosomy is reported. The conditioning regimen consisted of thiotepa (150 mg/m2 x 4), melphalan (70 mg/m2 x 2) and 12 Gy total body irradiation. She received peripheral blood CD34 positive cells (4.17 x 10(6)/kg) from her HLA-mismatched father and tacrolimus hydrate was used for GVHD prophylaxis. Engraftment was rapid and grade 1 acute GVHD of the skin responded well to pulse therapy. From day 27 she became irritable and sleepless, and right facial convulsions developed on day 37. No abnormality was found in the cerebrospinal fluid. Cranial CT findings showed no abnormalities except for low density lesions around the bilateral ventricle. Leukoencephalopathy was suspected and tacrolimus hydrate was discontinued. Thereafter psychosomatic symptoms improved, temporarily however, similar symptoms again developed following cyclosporine administration. Therefore we had to halt the administration of both tacrolimus and cyclosporine. She died on day 104 because of GVHD and fungal infection without recovering from leukoencephalopathy.

Brain Diseases↗
PubMed1996

Identification of a novel protein (VBP-1) binding to the von Hippel-Lindau (VHL) tumor suppressor gene product.

The tumor suppressor VHL gene product (pVHL), recently reported to bind to elongins B and C, is thought to regulate transcription elongation. To establish whether the VHL gene may have other functions, we here searched for additional cellular protein(s) that might bind to pVHL using a two-hybrid system and identified seven independent clones, including elongin C, but not elongin B. Three clones (unknown, imidopeptidase, and unknown) presumably bind to the N-terminal nonconserved region, whereas the four other clones [elongin C, the HIV tat-binding protein, the actin-binding protein Filamin (ABP280), and the HIBBJ46 (named VBP-1)] were found to bind to the wild-type pVHL but not to a C-terminal 156-amino acid deletion mutant. Interestingly, the HIV tat-binding protein and Filamin could bind to C-terminal 26-amino acid deleted pVHL, but elongin C and VBP-1 failed to do so. Thus, elongin C and VBP-1 require the C-terminal end of pVHL for binding. It was also established that epitope-tagged pVHL strongly forms complexes with VBP-1 in vivo using immunoprecipitation Western blotting analysis. VBP-1 was widely expressed in various cell lines tested, in which VHL mRNA can be detected. When the VBP-1 protein was solely expressed, it located to the cytoplasm and did not localize to the nucleus. However, when coexpressed with VHL, it can translocate to the nucleus. These results indicate that VBP-1 can form a complex with VHL protein in vivo and hence VHL affects the intracellular localization of VBP-1 protein.

Amino Acid Sequence↗
PubMed1996

Suppression of the neoplastic phenotype by replacement of the Tsc2 gene in Eker rat renal carcinoma cells.

The hereditary renal carcinoma (RC) in the rat, originally reported by R. Eker in 1954, is an excellent example of a Mendelian dominantly inherited predisposition to a specific cancer in an experimental animal. Recently, we have identified a germline mutation of the sclerosis (Tsc2) gene in the Eker rat (Nature Genetics 9, 70-74, 1995), suggested to be a novel tumor suppressor gene, fitting Knudson's two-hit hypothesis. In this study, the effect of wild-type Tsc2 gene expression in Eker RC cells was tested using a tetracycline-responsive promoter system. Transfection and expression of a exogenous Tsc2 gene affected both cell morphology and growth rate. This demonstration of suppression of the neoplastic phenotype provides direct evidence for an essential role of the Tsc2 gene in tumorigenesis.

Animals↗
PubMed1996

Presence of potent transcriptional activation domains in the predisposing tuberous sclerosis (Tsc2) gene product of the Eker rat model.

The Eker rat hereditary renal carcinoma is an excellent example of Mendelian dominant predisposition to a specific cancer in an experimental animal. We recently reported that a germline insertion in the rat homologue of the human tuberous sclerosis gene (TSC2) gives rise to dominantly inherited cancer in the Eker rat model, as well as a tumor suppressor nature for the Tsc2 gene function. We also showed a strong conservation between the rat and human gene products. The molecular function of the Tsc2 gene product (called "tuberin" in the human case) is not yet understood, although it contains a short amino acid sequence homologous to ras family GTPase-activating proteins (Rap1GAP). Here, we describe transcriptional activation domains (AD1 and AD2) in the carboxyl terminus of the Tsc2 product (in exons 30 and 32 and exon 41, respectively). The Eker insertional mutation (intron 30) disrupts their transcriptional activity. Whereas a COOH-terminal truncated Tsc2 protein was localized in the nucleus, the full-length protein is found predominantly in the perinuclear region of cytoplasm. The present demonstration of transcriptional activation domains in the Tsc2 gene provides clues for studying its role in renal carcinogenesis.

Amino Acid Sequence↗
PubMed1996

Comparative study on the antibacterial activity of phytochemical flavanones against methicillin-resistant Staphylococcus aureus.

Differently substituted flavanones were isolated from Leguminosae and their antibacterial activity was comparatively studied against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MICs) of phytochemical flavanones to clinical isolates of MRSA were determined by a serial agar dilution method. The structure-activity relationship has indicated that 2',4'- or 2',6'-dihydroxylation of the B ring and 5,7-dihydroxylation of the A ring in the flavanone structure are important for significant anti-MRSA activity and that substitution with a certain aliphatic group at the 6- or 8-position also enhances the activity. Among the thirteen flavanones tested, tetrahydroxyflavanones with these structural characteristics isolated from Sophora exigua and Echinosophora koreensis showed intensive activity to inhibit the growth of all MRSA strains at 3.13-6.25 micrograms/ml. The present hydroxyflavanones would be useful in the phytotherapeutic strategy against MRSA infections.

Anti-Bacterial Agents↗
PubMed1996

Flavones with antibacterial activity against cariogenic bacteria.

Methanolic extracts obtained from 13 plants were studied for their antibacterial activity against cariogenic bacteria. Among them, the extract from Artocarpus heterophyllus showed the most intensive activity. Serial chromatographic purifications offered two active compounds which were identified as 6-(3-methyl-1-butenyl)-5,2',4'-trihydroxy-3-isoprenyl-7-methoxy flavone and 5,7,2',4'-tetrahydroxy-6-isoprenylflavone. Both isolates completely inhibited the growth of primary cariogenic bacteria at 3.13-12.5 micrograms/ml. They also exhibited the growth inhibitory effects on plaque-forming streptococci. These phytochemical isoprenylflavones would be potent compounds for the prevention of dental caries.

Anti-Bacterial Agents↗
PubMed1996

Urinary excretion of tetrahydro-beta-carbolines relating to ingestion of alcoholic beverages.

Tetrahydro-beta-carbolines, formed from aldehydes and tryptamine, have been suggested as potential biochemical markers for alcoholism. The excretion of 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) and 1,2,3,4-tetrahydro-beta-carboline (TBC) in human urine was studied to assess their possible origin. In urine collected after a drinking party, MTBC and TBC were excreted in significantly higher concentrations compared with sobriety. MTBC and TBC were contained in beer and wine at ng/ml levels, but not in distillate alcoholic beverages such as whisky, brandy, gin, etc. The urinary excretion of MTBC and TBC was elevated after drinking beer, whereas no change was observed after drinking whisky. When a human subject was orally administered with deuterated L-tryptophan together with drinking whisky, deuterated tryptamine was increasingly excreted in urine. However, no increase was found in urinary deuterated MTBC. These results indicate that the urinary excretion of MTBC and TBC associated with alcohol ingestion does not imply promotion of their in vivo formation, but the exogenous supply of MTBC and TBC by drinking alcoholic beverages containing them.

Adolescent↗