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Biomedical subjects

O Tanaka

Publications and source records attributed to O Tanaka.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intravalvular implantation technique for aortic valve replacement in aortitis syndrome.

BACKGROUND: Paravalvular leakage is one of the most serious complications of aortic valve replacement in patients with aortitis syndrome. The purpose of this study was to compare the effectiveness of the intravalvular implantation technique in preventing paravalvular leakage with that of the conventional technique. METHODS: Since 1982, 14 patients with aortic regurgitation caused by aortitis syndrome have undergone aortic valve replacement at our institute. An intravalvular implantation technique was applied in 7 of the 14 patients. The technique consists of suturing a prosthetic valve to the aortic annulus and sandwiching the leaflets between exogenous felt pledgets and the inflamed aortic annulus. RESULTS: Paravalvular leakage occurred in 3 of 7 patients in the conventionally treated group and in none of 7 in the intravalvular implantation group. CONCLUSIONS: The intravalvular implantation technique is effective in preventing paravalvular leakage in patients with aortitis syndrome.

Adult↗
PubMed1999

Evaluation of the accuracy of preoperative staging in thoracic esophageal cancer.

BACKGROUND: Exact clinical staging before treatment of esophageal cancer has become increasingly important in the evaluation and comparison of the results of different treatment modalities, including surgery, chemotherapy, and radiotherapy. METHODS: The accuracy of preoperative tumor staging by using an esophagography, esophagoscopy, percutaneous and endoscopic ultrasonography, and computed tomography was assessed in 224 patients with resectable esophageal cancer. The results of tumor staging by these tests were compared prospectively with the pathologic stage of the esophagectomy specimens with respect to the T and N categories defined by the International Union Against Cancer TNM classification. RESULTS: For the T category, the overall accuracy was 80%. For the N category, overall accuracy was 72%, with a sensitivity of 78%, a specificity of 60%, and a positive predictive value of 78%. Overall, the accuracy of stage grouping was 56%. CONCLUSIONS: Either the T or N categories can be predicted reliably by clinical staging techniques. However, the preoperative stage grouping might not be valid in resectable, localized esophageal cancer.

Adult↗
PubMed1999

BDNF and NT-3 but not CNTF counteract the Ca2+ ionophore-induced apoptosis of cultured cortical neurons: involvement of dual pathways.

The effect of neurotrophic factors on apoptosis induced by ionomycin, a potent Ca2+ ionophore, was investigated using cultured cortical neurons from embryonic rats. Brain-derived neurotophic factor (BDNF) and neurotrophin-3 (NT-3) prevented the ionomycin-mediated cell death in a dose-dependent manner. In contrast to the neurotrophins, cilliary neurotrophic factor (CNTF) did not rescue neurons from cell death induced by ionomycin. The protective effect of BDNF was partially blocked by wortmannin, a phosphatidylinositol 3-kinase inhibitor, and by PD98059, a MAP kinase kinase inhibitor. However, the addition of both compounds together completely inhibited the survival promoting effect of BDNF. These results suggest that the neuroprotective effect of BDNF requires activation of both phosphatidylinositol-3 kinase and the Ras/MAP kinase cascade and that CNTF signaling through other pathways is without an effect in this system.

Androstadienes↗
PubMed1999

The effect of auricular acupuncture on olfactory acuity.

The modulation of olfactory thresholds by auricular acupuncture at a specific auricular acupuncture point was examined. The Lung Point, supplied by the auricular branch of the vagus nerve, was employed in a controlled single blind study of a randomized population of 23 healthy volunteers. Two odorous substances, beta-Phenyl ethyl alcohol and Methyl cyclopentenolone were used to evaluate the modulation of olfactory thresholds after acupuncture. A significant decrease in the olfactory recognition threshold by acupuncture in comparison with controls (P < 0.05) for two standard odors was observed. Our findings suggest that auricular acupuncture stimulation can decrease the recognition threshold of olfactory sensitivity.

Acupuncture Therapy↗
PubMed1999

Prognostic significance of magnetic resonance imaging of femoral marrow in patients with myelodysplastic syndromes.

PURPOSE: To investigate whether the abnormalities observed on femoral marrow magnetic resonance images are related to the development of leukemia and survival of patients with myelodysplastic syndromes (MDS). PATIENTS AND METHODS: The findings on magnetic resonance images of the femoral marrow were evaluated over periods of 1 to 92 months (median, 18 months) in 42 consecutive adult patients with newly diagnosed MDS. Magnetic resonance images were obtained by the T1-weighted spin echo method and the short T1 inversion recovery technique. RESULTS: Magnetic resonance images showed that the femoral marrow patterns changed from fatty, faint, or nodular to scattered or uniform as the disease progressed. Development of acute myeloid leukemia was observed in only 13 patients whose marrow exhibited a scattered or uniform pattern. The overall survival of the 29 patients with a scattered or uniform marrow pattern was significantly shorter than that of the 13 patients with a fatty, faint, or nodular marrow pattern (10.7% v 73.3% at 7 years; P < .01). The period of leukemia-free survival was also significantly shorter in the patients with a scattered or uniform marrow pattern versus a fatty, faint, or nodular pattern (37.7% v 100% at 7 years; P < .01). CONCLUSION: Magnetic resonance images of the femoral marrow can provide valuable information for assessing the prognosis and determining the most appropriate management of patients with MDS.

Acute Disease↗
PubMed1999

[Postoperative respiratory failure resulting from perioperative withdrawal of antiparkinsonian medications].

A patient with Parkinson's disease developed postoperative respiratory arrest due to perioperative withdrawal of antiparkinsonian medications and later presented a rapid recovery after parenteral administration of levodopa. In perioperative management of parkinsonian patients, it is important to continue antiparkinsonian medications until the operation is started and to administer levodopa parenteraly after the operation until oral administration of antiparkinsonian drugs becomes possible. In addition, we must pay attention to the choice of drugs so that parkinsonism may not be induced or aggravated.

Aged↗
PubMed1999

[Development of a multiple side-hole sheath introducer for use in aortography].

We developed a multiple side-holed sheath introducer that can also be used as a catheter for aortography before selective arteriography of the pelvic organs or lower extremities, as an alternative to straight or pig-tail catheters, which were formerly used for aortography. Aortography using the multiple side holed sheath introducer provided good detection of arteries in 100% of 10 cases, without any complications or difficulties. Thus, the present sheath introducer can replace straight or pig-tail catheters, resulting in the more economical use of one catheter prior to selective arteriography.

Aortography↗
PubMed1999

[A case of advanced gastric cancer with abdominal para-aortic lymph node metastasis successfully treated with FLP therapy].

A 73-year-old woman was admitted to our hospital in June 1998, suffering from upper abdominal pain. The upper G-I series and endoscopic examination revealed stenosis of the pylorus and antrum by a type 2 cancer, and a poorly differentiated adenocarcinoma and a signet-ring cell carcinoma were confirmed on endoscopic biopsy. A CT scan showed the enlargement of many regional and abdominal para-aortic lymph nodes. FLP therapy combined with cisplatin (50 mg/m2 drip i.v., day 1-8), 5-fluorouracil (333 mg/m2 drip i.v.) and leucovorin (30 mg/body i.v., day 1-8) was planned for neoadjuvant chemotherapy (NAC) in order to reduce or eliminate the tumor and increase curability. After two cycles of the FLP therapy, the tumor size shrunk remarkably and the enlargement of the para-aortic lymph nodes disappeared. Distal gastrectomy with extended lymphadenectomy and cholecystectomy was performed. The histological findings of the primary tumor and metastatic lymph nodes demonstrated massive cancer cell degeneration such as pycnosis and vacuolation, xanthogranulomatous inflammation and dense fibrosis. The effect of NAC was judged to be grade 2 histologically. FLP therapy is an effective and safe regimen for NAC.

Adenocarcinoma↗
PubMed1998

Cerebellar microfolia and other abnormalities of neuronal growth, migration, and lamination in the Pit1dw-J homozygote mutant mouse.

The Snell dwarf mouse (Pit1dw-J homozygote) has a mutation in the Pit1 gene that prevents the normal formation of the anterior pituitary. In neonates and adults there is almost complete absence of growth hormone (GH), prolactin (PRL), thyroxin (T4), and thyroid-stimulating hormone (TSH). Since these hormones have been suggested to play a role in normal development of the central nervous system (CNS), we have investigated the effects of the Pit1dw-J mutation on the cerebellum and hippocampal formation. In the cerebellum, there were abnormalities of both foliation and lamination. The major foliation anomalies were 1) changes in the relative size of specific folia and also the proportional sizes of the anterior vs posterior cerebellum; and 2) the presence of between one and three microfolia per half cerebellum. The microfolia were all in the medial portion of the hemisphere in the caudal part of the cerebellum. Each microfolium was just rostral to a normal fissure and interposed between the fissure and a normal gyrus. Lamination abnormalities included an increase in the number of single ectopic granule cells in the molecular layer in both cerebellar vermis (86%) and hemisphere (40%) in comparison with the wild-type mouse. In the hippocampus of the Pit1dw-J homozygote mouse, the number of pyramidal cells was decreased, although the width of the pyramidal cell layer throughout areas CA1-CA3 appeared to be normal, but less densely populated than in the wild-type mouse. Moreover, the number of granule cells that form the granule cell layer was decreased from the wild-type mouse and some ectopic granule cells (occurring both as single cells and as small clusters) were observed in the innermost portion of the molecular layer. The abnormalities observed in the Pit1dw-J homozygote mouse seem to be caused by both direct and indirect effects of the deficiency of TSH (or T4), PRL, or GH rather than by a direct effect of the deletion of Pit1.

Animals↗
PubMed1998

Compressive force promotes sox9, type II collagen and aggrecan and inhibits IL-1beta expression resulting in chondrogenesis in mouse embryonic limb bud mesenchymal cells.

The initial modeling and subsequent development of the skeleton is controlled by complex gene-environment interactions. Biomechanical forces may be one of the major epigenetic factors that determine the form and differentiation of skeletal tissues. In order to test the hypothesis that static compressive forces are transduced into molecular signals during early chondrogenesis, we have developed a unique three-dimensional collagen gel cell culture system which is permissive for the proliferation and differentiation of chondrocytes. Mouse embryonic day 10 (E10) limb buds were microdissected and dissociated into cells which were then cultured within a collagen gel matrix and maintained for up to 10 days. Static compressive forces were exerted onto these cultures. The time course for expression pattern and level for cartilage specific markers, type II collagen and aggrecan, and regulators of chondrogenesis, Sox9 and IL-1beta, were analyzed and compared with non-compressed control cultures. Under compressive conditions, histological evaluation showed an apparent acceleration in the rate and extent of chondrogenesis. Quantitatively, there was a significant 2- to 3-fold increase in type II collagen and aggrecan expression beginning at day 5 of culture and the difference was maintained through 10 days of cultures. Compressive force also causes an elevated level of Sox9, a transcriptional activator of type II collagen. In contrast, the expression and accumulation of IL-1beta, a transcriptional repressor of type II collagen was down-regulated. We conclude that static compressive forces promote chondrogenesis in embryonic limb bud mesenchyme, and propose that the signal transduction from a biomechanical stimuli can be mediated by a combination of positive and negative effectors of cartilage specific extracellular matrix macromolecules.

Aggrecans↗
PubMed1998

Single oral dose kinetics of zotepine and its relationship to prolactin response and side effects.

The authors investigated the single oral dose kinetics of zotepine and its relationship with prolactin response and side effects in 14 healthy male volunteers. Each subject took a single oral 25-mg dose of zotepine, and plasma concentrations of zotepine, prolactin, and their side effects were monitored up to 36 hours after dosing. The means +/- SD of the time of maximal plasma concentration (tmax), the apparent oral clearance, the apparent volume of distribution, and the elimination half-life (t1/2) were 3.8 +/- 1.2 hours, 4.6 +/- 4.2 1/h.kg, 109.0 +/- 59.0 1/kg, and 21.0 +/- 8.9 hours, respectively. The change in prolactin concentrations and side effect scores were parallel with that of drug concentrations, although no significant correlation was found between these three parameters at any time-point. The current results clearly indicate that the tmax and t1/2 of zotepine are much longer than those previously reported, which are reflected in the changes in prolactin concentrations and side effect scores.

Administration, Oral↗
PubMed1998

Adenovirus-mediated ectopic expression of Msx2 in even-numbered rhombomeres induces apoptotic elimination of cranial neural crest cells in ovo.

Distinct cranial neural crest-derived cell types (a number of neuronal as well as non-neuronal cell lineages) are generated at characteristic times and positions in the rhombomeres of the hindbrain in developing vertebrate embryos. To examine this developmental process, we developed a novel strategy designed to test the efficacy of gain-of-function Msx2 expression within rhombomeres in ovo prior to the emigration of cranial neural crest cells (CNCC). Previous studies indicate that CNCC from odd-numbered rhombomeres (r3 and r5) undergo apoptosis in response to exogenous BMP4. We provide evidence that targeted infection in ovo using adenovirus containing Msx2 and a reporter molecule indicative of translation can induce apoptosis in either even- or odd-numbered rhombomeres. Furthermore, infected lacZ-control explants indicated that CNCC emigrated, and that 20% of these cells were double positive for crest cell markers HNK-1 and beta-gal. In contrast, there were no HNK-1 and Msx2 double positive cells emigrating from Msx2 infected explants. These results support the hypothesis that apoptotic elimination of CNCC can be induced by 'gain-of-function' Msx2 expression in even-numbered rhombomeres. These inductive interactions involve qualitative, quantitative, positional and temporal differences in TGF-beta-related signals, Msx2 expression and other transcriptional control.

Adenoviridae↗
PubMed1998

Bioactive saponins and glycosides. XI. Structures of new dammarane-type triterpene oligoglycosides, quinquenosides I, II, III, IV, and V, from American ginseng, the roots of Panax quinquefolium L.

The methanolic extract and 1-butanol-soluble fraction of American ginseng, the roots of Panax quinquefolium L., were found to exhibit a protective effect on liver injury induced by D-galactosamine and lipopolysaccharide. Five new dammarane-type triterpene oligoglycosides called quinquenosides I, II, III, IV, and V were isolated together with fourteen known dammarane-type triterpene oligoglycosides such as chikusetsusaponin IVa, pseudo-ginsenoside-RC1, malonyl-ginsenoside-Rb1, and notoginsenosides-A,-C, and -K from the 1-butanol-soluble fraction. From the ethyl acetate-soluble fraction, four known acetylenic compounds and 6'-O-acetyl ginsenoside-Rg1 were isolated. The structures of quinquenosides I, II, III, IV, and V were determined on the basis of chemical and physicochemical evidence as 3-O-[6-O-(E)-2-butenoyl-beta-D-glucopyranosyl(1-->2)-beta-D- glucopyranosyl]-20-O-(beta-D-glucopyranosyl) 20(S)-protopanaxadiol (quinquenoside I), 3-O-[6-O-(E)-2-octenoyl-beta-D- glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] 20(S)-protopanaxadiol (quinquenoside II), 3-O-[beta-D-glucopyranosyl (1-->2)-6-O-acetyl-beta-D-glucopyranosyl]-20-O-(beta-D-glucopyranosyl) 20(S)-protopanaxadiol (quinquenoside III), 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-beta-D- glucopyranosyl(1-->6)-beta-D-glucopyranosyl]-3 beta, 7 beta, 20(S)-trihydroxydammar-5,24-diene (quinquenoside IV), and 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-20-O-[alpha-D- glucopyranosyl(1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl ] 20(S)-protopanaxadiol (quinquenoside V).

Animals↗
PubMed1998

Skin sensitization and photosensitization studies of hydrophobically modified hydroxypropyl methylcellulose in guinea pigs.

Skin sensitization and photosensitization tests of hydrophobically modified hydroxypropyl methylcellulose (HM-HPMC), a new cellulose derivative used as a thickener for topical pharmaceuticals, were conducted using guinea pigs. An aqueous dispersion of HM-HPMC (3 w/v %) was applied in the tests. Skin reaction was not observed in any animal in the HM-HPMC-treated group or control group. In the photosensitization test, no skin reaction was found in any animal in the test-preparation group or the control group. It was concluded that HM-HPMC dispersion does not exhibit skin sensitizing or photosensitizing activity under the condition of this test.

Adjuvants, Pharmaceutic↗
PubMed1998

Bone marrow involvement in lymphoma: the importance of marrow magnetic resonance imaging.

Detection of bone marrow involvement is important for staging and treatment decisions in patients with lymphoma. Although routine bone marrow evaluation is based on aspirates and bone marrow biopsies, new diagnostic tools are required to improve diagnostic accuracy. Visual and quantitative assessment of the bone marrow by magnetic resonance (MR) imaging is useful for the detection of occult lymphomatous marrow involvement. MRI is also suitable for the evaluation of disease extent in the bone marrow. Furthermore, abnormal images on marrow MRI may be associated with a significantly poorer survival in patients with lymphoma, regardless of histologic findings in the marrow. Evaluation of the bone marrow by MRI is essential to assess disease status in patients with lymphoma.

Biopsy↗
PubMed1998

Chondrocalcin as a marker of articular cartilage degeneration in anterior cruciate ligament-deficient knees.

This study assessed articular cartilage deterioration and the effect of meniscal tears to evaluate the usefulness of chondrocalcin as a joint fluid marker in 43 patients with anterior cruciate ligament (ACL) deficiency. A significant correlation was found between the cartilage damage and time after injury. The high incidence of long longitudinal tears of the medial meniscus with increased cartilage damage, especially in chronic cases, suggests that this type of meniscal tear contributed to the deterioration of ACL-deficient knees. Chondrocalcin concentrations were found to have a significant correlation with cartilage damage.

Adolescent↗
PubMed1998

[Flow cytometric analysis of proliferative activity of pleomorphic adenoma of salivary gland].

Pleomorphic adenoma (PA) of the salivary gland has diverse biological behavior in spite of its being a benign tumor. So the nuclear DNA content of 36 PAs was measured by flow cytometry to determine the relationship between proliferative activity and histopathological variable. DNA histograms were evaluated according to the rate of S and G2+ M phase cells (S + G2M%). We assumed that the DNA histogram measured algebraically, S + G2 M% < or = 0%, is the near diploid pattern and calculated its ratio to the near diploid pattern. A statistically significant difference between PA and normal salivary gland was found by the ratio to the near diploid pattern (P < 0.05), which confirmed the usefulness of the ratio to the near diploid pattern for measuring low proliferative activity. The tumors were divided into 3 groups: epitheloid type, intermediate type and myxochondroid type. In the 3 groups no differences were found by S + G2M% and the ratio to the near diploid pattern. The areas of the tumor were divided into 5 groups according to the ratio in the epitheloid region and the myxochondroid region. In the 5 groups, the area which consists partly of epitheloid components and mostly of myxochondroid components had the lowest ratio to the near diploid pattern and the highest S + G2M%, and the area which consists of only myxochondroid components had the highest ratio to the near diploid pattern and the lowest S + G2M%. Between only these two areas a statistically significant difference was found by the ratio to the near diploid pattern (P < 0.05). We considered that the area which consists partly of epitheloid components, and mostly of myxochondroid components has the highest proliferative activity in PA. Neither aneuploid or polyploid cells were found in any tumor, but the S + G2M% is more than 20% in 4 tumors. None of these high S + G2M% tumors except one recurrent tumor had clinical and histopathological features. A differences between PAs of the parotid glands and PAs of the submandibular glands was not found in S + G2M%.

Adenoma, Pleomorphic↗