Search PubMed⌕ Search

Biomedical subjects

M Hori

Publications and source records attributed to M Hori.

At least 307 records · Page 17Linked to original sources
PubMed1999

Releasing severe adhesions around the eminence and the synovial portion of the TMJ: a clinical study of combined treatment using hydraulic lavage, arthroscopic surgery and rehabilitative therapy.

This paper evaluates the effects of treatment with a pumping technique and arthroscopic lysis and lavage, followed by rehabilitative training, on condylar head mobility of the temporomandibular joint (TMJ). We studied 32 TMJs in 19 patients suffering from chronic closed lock with severe adhesion. The results were compared between cases with adhesions concentrated in two areas: mostly in the posterior and/or the anterior synovial portion of the upper TMJ compartment (11 joints) and mostly around the eminence (21 joints). The results showed a statistically significant improvement in condylar head movement for both groups between the initial and final stages of treatment. However, the results also suggested that patients with adhesion concentrated around the eminence are less likely to recover condylar head mobility to the same extent as those in the other group.

Adult↗
PubMed1999

Beneficial effects of antioxidants in diabetes: possible protection of pancreatic beta-cells against glucose toxicity.

Oxidative stress is produced under diabetic conditions and possibly causes various forms of tissue damage in patients with diabetes. The aim of this study was to examine the involvement of oxidative stress in the progression of pancreatic beta-cell dysfunction in type 2 diabetes and to evaluate the potential usefulness of antioxidants in the treatment of type 2 diabetes. We used diabetic C57BL/KsJ-db/db mice, in whom antioxidant treatment (N-acetyl-L-cysteine [NAC], vitamins C plus E, or both) was started at 6 weeks of age; its effects were evaluated at 10 and 16 weeks of age. According to an intraperitoneal glucose tolerance test, the treatment with NAC retained glucose-stimulated insulin secretion and moderately decreased blood glucose levels. Vitamins C and E were not effective when used alone but slightly effective when used in combination with NAC. No effect on insulin secretion was observed when the same set of antioxidants was given to nondiabetic control mice. Histologic analyses of the pancreases revealed that the beta-cell mass was significantly larger in the diabetic mice treated with the antioxidants than in the untreated mice. As a possible cause, the antioxidant treatment suppressed apoptosis in beta-cells without changing the rate of beta-cell proliferation, supporting the hypothesis that in chronic hyperglycemia, apoptosis induced by oxidative stress causes reduction of beta-cell mass. The antioxidant treatment also preserved the amounts of insulin content and insulin mRNA, making the extent of insulin degranulation less evident. Furthermore, expression of pancreatic and duodenal homeobox factor-1 (PDX-1), a beta-cell-specific transcription factor, was more clearly visible in the nuclei of islet cells after the antioxidant treatment. In conclusion, our observations indicate that antioxidant treatment can exert beneficial effects in diabetes, with preservation of in vivo beta-cell function. This finding suggests a potential usefulness of antioxidants for treating diabetes and provides further support for the implication of oxidative stress in beta-cell dysfunction in diabetes.

Acetylcysteine↗
PubMed1999

Impaired diurnal cardiac autonomic function in subjects with type 2 diabetes.

OBJECTIVE: To assess diurnal cardiac sympathetic and parasympathetic nerve functions in diabetic subjects with variable diabetic neuropathy. RESEARCH DESIGN AND METHODS: Frequency domain analysis of 24-h Holter ECG was done for 132 diabetic subjects (84 without any symptomatic neuropathy; 37 with only symptomatic peripheral neuropathy; 11 with symptomatic autonomic neuropathy) and 57 normal volunteers to calculate the low frequency (LF) component representing the beta-adrenoceptor function and the high frequency (HF) component representing the cardiac parasympathetic nerve function. RESULTS: Cardiac LF and HF components in diabetic subjects without peripheral neuropathy showed values comparable to those of normal volunteers and a similar circadian rhythm. Diabetic subjects with peripheral neuropathy or autonomic neuropathy showed significantly depressed LF and HF components and loss of the circadian rhythm of LF and HF components compared with diabetic subjects without neuropathy. Impairment of the LF component in the afternoon could be accounted for by the duration of diabetes and elevated HbA1c level. Impairment of the HF component at night could be accounted for by the duration of diabetes but not an elevated HbA1c level. CONCLUSIONS: These data indicated that diabetic subjects with peripheral neuropathy and diabetic subjects with symptomatic autonomic neuropathy, but not diabetic subjects without neuropathy, showed a marked decrease in cardiac sympathetic and parasympathetic nerve functions and loss of circadian rhythm.

Adult↗
PubMed1999

High-dose chemotherapy with peripheral blood stem cell rescue in blastoid natural killer cell lymphoma.

A 25-year-old man was referred because of skin rash, lymphadenopathy and anemia. Laboratory examinations revealed severe anemia (Hb, 4.8 g/dl) and elevated levels of GOT, GPT, LDH and soluble interleukin-2 receptor. Work-up studies disclosed the involvement of lymphoma cells in lymph nodes, skin, bilateral kidneys and bone marrow. Lymph node biopsy revealed diffuse proliferation of medium- to large-sized lymphoblastic cells. Bone marrow aspiration showed massive infiltration of large blastic cells with no cytoplasmic granules. The lymphoma cells in bone marrow and lymph node showed surface CD3-, cytoplasmic CD3epsilon+, CD4+, CD8-, CD56+, CD57-, CD16- and CD43 (MT-1)+ phenotype. Analyses of T cell receptor beta and gamma genes showed germ line configurations. EBER-1 was not detectable in the lymphoma cells. He was diagnosed as having blastoid natural killer (NK) cell lymphoma. In spite of several courses of combination chemotherapy, the lymphoma was progressive. He was then treated with high-dose chemotherapy and peripheral blood stem cell rescue, achieving remission which has now lasted for more than 12 months. We consider that blastoid NK cell lymphoma is an extremely aggressive subtype of CD56-positive lymphomas, and high-dose chemotherapy with peripheral blood stem cell rescue should be included for the choice of the treatment.

Adult↗
PubMed1999

Effect of thiazinotrienomycin B, an ansamycin antibiotic, on the function of epidermal growth factor receptor in human stomach tumor cells.

Thiazinotrienomycin B (TT-B), an ansamycin isolated from fermentation broths of Streptomyces sp. MJ672-m3, inhibited the growth in vitro of human stomach tumor SC-6 cells over 10 times more strongly than the growth of other human tumor cells, such as HeLa (cervix), T24 (bladder) and LX-1 (lung). The extent of growth inhibition by TT-B of SC-6, but not of LX-1 nor T24, was lowered in a competitive manner by raising serum concentrations in the culture medium. TT-B inhibited the cell cycle progression of SC-6 at an early stage of the progression from G0/G1 to S. The inhibition was again competitive with serum concentrations in the culture medium. No direct inhibition of DNA synthesis was observed at the concentration range which caused the cell cycle arrest. TT-B and anti-epidermal growth factor receptor (anti-EGFR) were antagonistic to each other in inhibiting the cell cycle progression of SC-6 from G0/G1 to S, suggesting that the two compounds share the same target, EGFR. The kinase activity of EGFR was little inhibited by TT-B in a cell-free system.

Anti-Bacterial Agents↗
PubMed1999

[Application of MR-guided intravascular procedures by passive tracking utilizing the magnetic susceptibility effect: a preliminary report].

In MR-guided intravascular procedures, the position of catheters must be confirmed on near-real-time MR images. One way of monitoring this is by passive tracking utilizing the magnetic susceptibility effect. A catheter with a stainless steel braid had suitable visibility when tracked by magnetic susceptibility on fast GRE images, although the direction of the static magnetic field affected the apparent width of the catheter. Passive tracking with a 1.5T MRI unit was performed in a patient at one image/2 seconds with fast GRE. The catheter could be introduced to the SMA and celiac artery from the aorta with passive tracking.

Animals↗
PubMed1999

[Evaluation of two-dimensional thick-slice MR DSA: preliminary study].

We have used two-dimensional contrast-enhanced MR angiography for a single thick slice and called it MR DSA. This technique realizes nearly subsecond scanning per image and is therefore superior to other types of contrast-enhanced MR angiography in temporal resolution. To determine the optimal parameters of this technique, we calculated SSR (the signal of brain to the signal of contrast agent ratio) in various settings. We also obtained MR DSA images of 26 cases. We believe that MR DSA may play a supportive role in conventional MR imaging or angiography, since its high temporal resolution is of value in the evaluation of cerebrovascular diseases.

Angiography, Digital Subtraction↗
PubMed1999

[Efficacy of angiotensin II receptor antagonists as a novel drug for the treatment of chronic heart failure--in comparison with ACE inhibitors].

Since 1) renin-angiotensin-aldosterone systems play an critical role in the development and progression of chronic heart failure, and 2) inhibitors of angiotensin converting enzyme (ACEIs) are proved to be effective for the treatment of chronic heart failure, angiotensin II receptor antagonists may be more effective than ACEIs. This is because angiotensin II receptor antagonists can inhibit the effects of angiotensin II via ACE-independent pathways, e.g., chymase. On the other hand, ACEIs can increase bradykinin, and thus, nitric oxide, which may cause potent cardioprotection. Therefore, angiotensin II receptor antagonists and ACEIs may mediate cardioprotection via different mechanisms, which may hint the combination therapy of both drugs in the pathophysiology of chronic heart failure. Angiotensin II receptor antagonists may open a new era for the treatment of chronic heart failure.

Angiotensin Receptor Antagonists↗
PubMed1999

Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPECT.

UNLABELLED: We compared the left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars automated quantitative gated SPECT (QGS) to those determined by first-pass radionuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a group of 21 patients (mean age 61.4 +/- 9.2 y). METHODS: A total of 740 MBq 99mTc-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour after injection, QGS was performed with a temporal resolution of 10 frames per R-R interval. LVG was performed within 2 wk. RESULTS: The EDV, ESV and LVEF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determined by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). There was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there was an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was significantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction values were highest by LVG (57.1% +/- 3.2%), then QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%). CONCLUSION: QGS gave more reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.

Adult↗
PubMed1999

Validity of 18F-fluorodeoxyglucose imaging with a dual-head coincidence gamma camera for detection of myocardial viability.

UNLABELLED: This study investigated the validity of myocardial 18F-fluorodeoxyglucose (FDG) imaging with a dual-head gamma camera operated in coincidence detection mode (DCD-I) by comparing this technique with conventional PET and SPECT with ultra-high-energy general-purpose collimators (UHGPs). METHODS: The subjects included 5 healthy volunteers and 20 patients with a history of myocardial infarction. FDG (370 MBq) was injected intravenously after 75-g oral glucose loading, and PET, UHGP SPECT and DCD-I were performed 45, 60 and 210 min, respectively, after the injection. The target-to-background ratio of each imaging method was evaluated for the healthy volunteers by comparing myocardial uptake with uptake in the upper lungs or left ventricular cavity. Agreement between the results of the various imaging methods was investigated for the myocardial infarction patients, as was the validity of DCD-I for assessing myocardial viability as judged by comparison with myocardial perfusion SPECT. The left ventricular wall was divided into 18 regions, and uptake was evaluated using a five-grade defect score (0 = normal; 1-3 = low uptake; 4 = defect). RESULTS: The mean ratio of myocardial counts to lung counts was lower on the DCD images (2.77 +/- 1.12) than on the UHGP SPECT images (3.69 +/- 0.98) (P < 0.05). In contrast, the mean ratio of myocardial counts to left ventricular cavity counts was higher on the DCD images (2.76 +/- 1.36) than on the UHGP SPECT images (1.98 +/- 0.70) (P < 0.05). For the patients, only 30.6% of the defect scores obtained by DCD-I agreed with the scores obtained by PET, and the defect scores in the inferior and septal walls were higher for the DCD images than for the PET images. When DCD-I was compared with PET without attenuation correction (AC), agreement improved to 58.3%. When corrected by a modified AC method, DCD-I improved to 48.1%. Agreement between UHGP SPECT and PET was 55.0%. Of the segments (64) for which the defect score of the myocardial perfusion image was greater than that for the FDG PET image, DCD-I without AC, DCD-I with AC and UHGP SPECT allowed an accurate diagnosis in 12 (18.8%), 31 (48.4%) and 43 (67.2%), respectively. CONCLUSION: The image quality of DCD-I is superior to that of UHGP SPECT. However, because the effect of attenuation is marked, accurate AC, by the transmission method, for example, is required to equal the validity of PET.

Female↗
PubMed1999

Cyclooxygenase inhibitors suppress angiogenesis and reduce tumor growth in vivo.

Angiogenesis plays a key role in the development of malignant tumors. To clarify the roles of cyclooxygenase (COX) in malignant tumor development and angiogenesis, we investigated the effects of COX inhibitors on two kinds of gastrointestinal cancer xenograft, one of which overexpresses COX-2 and the other expresses no COX, in nude mice in vivo. There was a positive correlation between tumor volume and angiogenesis within the xenograft. Oral administration with a specific COX-2 or a nonspecific COX inhibitors lowered the expression of potent angiogenic factors; vascular endothelial growth factor and basic fibroblast growth factor, reduced angiogenesis and growth, induced apoptosis, and suppressed cell replication of the COX-2 overexpressing cancer xenografts in a dose-dependent manner. A nonspecific COX inhibitor, not a specific COX-2 inhibitor, reduced growth and angiogenesis of non-COX expressing cancer xenograft by inhibition of COX-1 in vascular endothelial cells. These results demonstrate that COX inhibitors suppress angiogenesis and tumor growth by inhibiting expression of angiogenic factors and vascular endothelial cell growth. They support the hypothesis that COX plays an important role in cancer growth via angiogenesis. These findings offer a new strategy against cancer using COX inhibitors (nonsteroidal anti-inflammatory drugs).

Animals↗
PubMed1999

[Microcirculatory derangement and apoptosis in ischemia-reperfusion injury].

This study was undertaken to clarify the involvement of microcirculatory failure and apoptosis in the pathophysiology of cerebral ischemia using ICAM-1 knockout mice (K/O) and BCL-2 transgenic mice, respectively. In both permanent and transient focal ischemia, infarcted size of cerebral cortex in ICAM-1 K/O mice was significantly smaller than that in wild type mice. Microcirucaltaory disturbance in the cerebral cortex after permanent and transient focal ischemia was mitigated in ICAM-1 K/O mice compared with that in wild type mice. However, the number of granulocytes in the infarcted tissue was similar between K/O and wild mice, and neutrophil depletion in K/O mice showed further reduction of cortical infarction after transient focal ischemia. In contrast, neuronal overexpression of BCL-2 in mice showed protective effect on selective neuronal death observed in the hippocampus after transient global forebrain ischemia for 12 min. The present study supported the notion that (1) microcirculatory disturbance mediated through interaction of ICAM-1 and leukocytes played an important role in expansion of cerebral infarction after focal ischemia and (2) apoptosis inhibited in part by overexpression of BCL-2 was involved in selective neuronal vulnerability after transient global ischemia.

Animals↗
PubMed1998

Effects of human PTH(1-34) and bisphosphonate on the osteopenic rat model.

It has been demonstrated that the intermittent administration of human parathyroid hormone (hPTH) is beneficial for restoration of bone mass in osteoporotic patients. The mechanisms of anabolic effects of hPTH have been determined by ovariectomized rat models and other larger remodeling animals. However, treatment with hPTH may increase the cancellous bone mass at the expense of cortical bone mass and cessation of the treatment results in rapid bone loss. Efforts have been made to maintain newly formed bone mass after withdrawal of the hPTH treatment. These issues are not well understood. In this article, the authors would like to represent previous studies of their own and others concerning these issues.

Animals↗
PubMed1998

Involvement of NF-Y in transcriptional regulation of the phospholamban gene.

To understand the transcriptional regulation of the phospholamban gene, we analyzed a 5'-upstream region of the gene. Using a series of deletion constructs, we demonstrated that the region from -96 bp to -78 bp, containing the CCAAT sequence, is essential for transcription of this gene. This region specifically bound to nuclear proteins extracted from rat hearts, and gel-shift assays using competitive oligonucleotides, antibodies and recombinant proteins showed that this region binds to the NF-YA and NF-YB, members of the CCAAT-binding nuclear protein family. This region-dependent transcription in cardiac myocytes transfected with antisense cDNAs encoding NF-YA and NF-YB was decreased to approximately 50% of that seen in cells transfected with the same sense cDNAs. We, therefore, conclude that the region from -96 bp to -78 bp plays a critical role in expression of the phospholamban gene, which is regulated by binding of the nuclear protein NF-Y.

Animals↗
PubMed1998

Oscillation maintains polymorphisms - a model of lateral asymmetry in two competing scale-eating cichlids

Scale-eating cichlids in Lake Tanganyika exhibit lateral asymmetry polymorphism in their mouth-opening. Frequency of left- and right-handed phenotypes oscillates around unity. In the southern shore of the lake, two scale-eaters coexist in similar densities, where their oscillation synchronize. This phenomena is analysed by a time delay differential equation model, and new mechanisms which maintains polymorphism is discovered. In a wide range of parameters, the oscillation keeps the frequencies of the same phenotype in the two species at a similar level, and prevents the fixation of one phenotype in either species. Copyright 1998 Academic Press

Journal Article↗