[Rhythm control and rate control as therapy for patients with atrial fibrillation].
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Adrenergic beta-Antagonists↗
Biomedical subjects
Hiroshi Nishimura
Publications and source records attributed to Hiroshi Nishimura.
Giant cell-rich osteosarcoma of the distal femur: radiographic and magnetic resonance imaging findings.
We report a case of giant cell-rich osteosarcoma in the right distal femur of a 32-year-old man. Giant cell-rich osteosarcomas are sometimes difficult to distinguish from giant cell tumors by age, location, magnetic resonance imaging findings, and pathology. Radiography may be useful in the diagnosis of giant cell-rich osteosarcoma.
Adult↗
A closed biatrial procedure using bipolar radiofrequency ablation.
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Aged↗
Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field.
A novel thermophilic bacterium, strain KW1(T), was isolated from a coastal hydrothermal field on the Satsuma Peninsula, Kagoshima Prefecture, Japan. The variably Gram-stained cells were motile rods with flagella, did not form spores and proliferated at 52-78 degrees C (optimum, 70 degrees C), pH 5-8 (optimum, pH 7) and 0-4.5 % NaCl (optimum, 1.0 %). The novel isolate was a strictly aerobic heterotroph that utilized complex proteinaceous substrates as well as a variety of carboxylic acids and amino acids. The G+C content of the genomic DNA was 70.8 mol%. Analysis of 16S rRNA gene sequences indicated that strain KW1(T) is closely related to Thermaerobacter subterraneus C21(T) (98.4 % sequence similarity). However, the DNA-DNA hybridization value for strain KW1(T) and T. subterraneus ATCC BAA-137(T) was below 46 %. On the basis of the molecular and physiological traits of strain KW1(T), it represents a novel species of the genus Thermaerobacter, for which the name Thermaerobacter litoralis sp. nov. is proposed. The type strain is KW1(T) (=JCM 13210(T)=DSM 17372(T)).
Aerobiosis↗
Giant angioleiomyoma in extremity: report of two cases.
Angioleiomyomas are smooth muscle tumors that occur most often in the extremities and are usually less than 2 cm in diameter. We present 2 case reports of giant angioleiomyoma. Case 1 was a 51-year-old woman with a 5-year history of a slowly growing mass 12x10 cm in diameter in the right posterior thigh. The tumor was larger than any previously reported. Case 2 was a 72-year-old man with an 8-year history of a slowly growing mass 6x6 cm in diameter in the left palm. The tumor was unique in that it grew to a giant size in the hand of the elderly patient. Magnetic resonance imaging of both cases confirmed the tumors' presence in the subcutis. T1-weighted images showed homogenous signal isointense to muscle. On T2-weighted images, areas of hyperintensity and hypointensity intermingled. Three-dimensional gadolinium-enhanced magnetic resonance angiography showed rapid initial enhancement followed by a gradual increase in enhancement, suggesting that the tumors were rich in vessels. Microscopic examination revealed numerous vascular channels embedded within a huge smooth muscle component.
Aged↗
Neural mechanism of residual inhibition of tinnitus in cochlear implant users.
Residual inhibition is a transient suppression of tinnitus after auditory stimulation has stopped. We used positron emission tomography to study brain regions underlying residual inhibition in three tinnitus patients with cochlear implants and six normal hearing controls. Regional cerebral blood flow was measured and compared under two conditions: with tinnitus and during the residual inhibition of tinnitus. The right anterior middle and superior temporal gyri (Brodmann areas 21 and 38) were activated during residual inhibition, while the right cerebellum was activated during tinnitus perception in the tinnitus patients. No significant activation was observed in the normal controls. Our results suggest that tinnitus and residual inhibition are related to cortical networks of auditory higher-order processing, memory and attention.
Aged↗
Genetic regulation mediated by thiamin pyrophosphate-binding motif in Saccharomyces cerevisiae.
The expression of genes of Saccharomyces cerevisiae encoding the enzymes involved in the metabolism of thiamin (THI genes) is co-ordinately repressed by exogenous thiamin and induced in the absence of thiamin. In this yeast THI regulatory system acts mainly at the transcriptional level, thiamin pyrophosphate (TDP) seems to serve as a corepressor, and genetic studies have identified three positive regulatory factors (Thi2p, Thi3p and Pdc2p). We found in a DNA microarray analysis that the expression of THI genes increased 10- to 90-fold in response to thiamin deprivation, and likewise, the expression of THI2 and THI3 increased 17-fold and threefold, respectively. After transfer from repressing to inducing medium, the promoter activity of both THI2 and THI3 increased in parallel with that of PHO3, one of THI genes. The stimulation of THI3 promoter activity was diminished by deletion of THI3, indicative of the autoregulation of THI3. The THI genes were not induced when THI2 was expressed from the yeast GAL1 promoter in a thi3Delta strain or when THI3 was expressed in a thi2Delta strain, suggesting that Thi2p and Thi3p participate simultaneously in the induction. When mutant Thi3p proteins lacking TDP-binding activity were produced in the thi3Delta strain, THI genes were expressed even under thiamin-replete conditions. This result supports the hypothesis that Thi3p senses the intracellular signal of the THI regulatory system to exert transcriptional control. Furthermore, Thi2p and Thi3p were demonstrated to bind each other and this interaction was partially diminished by exogenous thiamin, suggesting that Thi2p and Thi3p stimulate the expression as a complex whose function is disturbed by TDP bound to Thi3p. We discuss the possibility that the induction of THI genes is triggered by the activation of the complex attributed to decrease in intracellular TDP and the elevated complex in the autoregulatory fashion further upregulates THI genes. This is the first report of the involvement of the TDP-binding motif in genetic regulation.
Cell Nucleus↗
[Usefulness of diffusion-weighted MRI in differentiating benign from malignant musculoskeletal tumors].
PURPOSE: To evaluate the usefulness of diffusion-weighted MRI in distinguishing different components and in differentiating benign from malignant musculoskeletal tumors. MATERIALS AND METHODS: Fifty-seven patients with musculoskeletal tumors underwent MR at our institution from October 1999 to April 2002. We evaluated 57 tumors (9 bone tumors and 48 soft tissue tumors). All tumors were classified into 8 groups (myxomatous, fibrous, cystic, cartilaginous, fatty components, hematomas, other benign tumors, and other malignant tumors). MR examinations were performed with a 1.5-Tesla system. Diffusion-weighted single-shot EPI images were obtained in all patients. Apparent diffusion coefficients (ADCs) were calculated by using b factors of 0 and 1,000 sec/mm2. RESULTS: ADC values of myxomatous, cystic, and cartilaginous components were significantly higher than those of other tumors. In cartilaginous tumors, malignant tumor ADC values (2.33 +/- 0.44) were higher than those of benign tumors (2.13 +/- 0.13). However, there was no significant difference between benign and malignant tumors. Except for high-intensity components on T1-weighted imaging and low or homogeneously very high intensity components on T2-weighted imaging, there was a significant difference in ADC between malignant (1.35 +/- 0.40) and benign (1.97 +/- 0.50) tumors. CONCLUSION: Within the limited number of cases, there was a significant difference in ADC between malignant and benign tumors.
Adolescent↗
Cortical processing of tactile language in a postlingually deaf-blind subject.
We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing.
Adult↗
Increased regional cerebral blood flow in the contralateral thalamus after successful motor cortex stimulation in a patient with poststroke pain.
The mechanisms underlying poststroke pain have not been clearly identified. Although motor cortex stimulation (MCS) sometimes reduces poststroke pain successfully, the exact mechanism is not yet known. For further investigation of the neural pathways involved in the processing of poststroke pain and in pain reduction by MCS, the authors used positron emission tomography (PET) scanning to determine significant changes in regional cerebral blood flow (rCBF). This 58-year-old right-handed man suffered from right-sided poststroke pain for which he underwent implantation of a stimulation electrode in the right motor cortex. After 30 minutes of stimulation, his pain was remarkably reduced (Visual Analog Scale scores decreased 8 to 1) and he felt warmth in his left arm. The rCBF was studied using PET scanning with 15O-labeled water when the patient was in the following states: before MCS (painful condition, no stimulation) and after successful MCS (painless condition, no stimulation). The images were analyzed using statistical parametric mapping software. State-dependent differences in global blood flow were covaried using analysis of covariance. Comparisons of the patient's rCBF in the painful condition with that in the painless condition revealed significant rCBF increases in the left rectus gyrus (BA11), left superior frontal lobe (BA9), left anterior cingulate gyms (BA32), and the left thalamus (p < 0.05, corrected). On the other hand, there were significant decreases in rCBF in the right superior temporal gyrus (BA22, p < 0.01, corrected) and the left middle occipital gyrus (BA19, p < 0.05, corrected). The efficacy of MCS was mainly related to increased synaptic activity in the thalamus, whereas the activations in the rectus gyrus, anterior cingulate gyrus, and superior frontal cortex as well as the inactivation of the superior temporal lobe may be related to emotional processes. This is the first report in which the contralateral thalamus was significantly activated and pain relief was achieved using MCS.
Cerebral Hemorrhage↗
[Fundamental study of magnetization transfer contrast (MTC) effect: optimization of MT pulse condition using experimental phantom].
Magnetization transfer contrast (MTC) was evaluated by changing the off-set frequency and pulse intensity of MTC with the spoiled gradient echo (SPGR) sequence (T2*-weighted image) using an experimental phantom that included olive oil, protein, fiber, collagen, and pure water. The intensity of pure water reached a constant level just above the off-set frequency (1200 Hz) regardless of MT pulse power. The contrast-to-noise ratio (CNR) in each of the phantom materials was maximal at the MT pulse power of 2500 degrees (equivalent flip angle). The CNR and image noise obtained by body coil were inferior to those obtained with an extremity coil. In clinical application, the MTC effect on chondrosarcoma was higher (MT ratio, ROI-1:0.448, ROI-2:0.382) than those of other cases in this study. Since the image contrast was improved between the malignant fibrous histiocytoma (MFH, MT ratio, ROI-1:0.282, ROI-2:0.289) and peripheral tissues, extraskeletal extension could be observed more easily than without MTC imaging. In conclusion, the effects of MTC might be in providing useful information, in presuming composed tissues, differential diagnoses, and extent to the surrounding structures because of changing the image contrast to surrounding tissues corresponding to the rate of included bound water.
Bone Neoplasms↗
A new norepinephrine transporter imaging agent for cardiac sympathetic nervous function imaging: radioiodinated (R)-N-methyl-3-(2-iodophenoxy)-3-phenylpropanamine.
Changes of the cardiac norepinephrine transporter (NET) have been reported in several cardiac failures. (R)-N-methyl-3-(2-iodophenoxy)-3-phenylpropanamine (MIPP), the 3-phenoxy-3-phenylpropylamine analogue iodinated at the 2-position of the phenoxy ring, was synthesized and evaluated as a potential radiopharmaceutical for investigating the cardiac norepinephrine transporter by single photon emission computed tomography (SPECT). (R)-[(125)I]MIPP was synthesized via a halogen exchange reaction under no-carrier-added conditions and purified by high-performance liquid chromatography (HPLC) with high radiochemical yield (60%) and high radiochemical purity (> 98%). The binding affinity of (R)-MIPP for cardiac NET was measured in terms of the displacement of [(3)H]desipramine and (R)-[(125)I]MIPP from binding sites in rat heart membranes. The binding data revealed that the affinity of (R)-MIPP was 5 times that of nisoxetine which is a selective NET inhibitor. In biodistribution studies, (R)-[(125)I]MIPP showed a high uptake followed by rapid clearance in the heart. (R)-[(125)I]MIPP binding sites were saturable and the administration of nisoxetine and desipramine, selective NET inhibitors, decreased the cardiac accumulation of (R)-[(125)I]MIPP. These results suggested that (R)-[(123)I]MIPP may be an useful radiopharmaceutical for imaging cardiac sympathetic nervous functions.
Animals↗
Identification of a helix-turn-helix motif of Bacillus thermoglucosidasius HrcA essential for binding to the CIRCE element and thermostability of the HrcA-CIRCE complex, indicating a role as a thermosensor.
In the heat shock response of bacillary cells, HrcA repressor proteins negatively control the expression of the major heat shock genes, the groE and dnaK operons, by binding the CIRCE (controlling inverted repeat of chaperone expression) element. Studies on two critical but yet unresolved issues related to the structure and function of HrcA were performed using mainly the HrcA from the obligate thermophile Bacillus thermoglucosidasius KP1006. These two critical issues are (i) identifying the region at which HrcA binds to the CIRCE element and (ii) determining whether HrcA can play the role of a thermosensor. We identified the position of a helix-turn-helix (HTH) motif in B. thermoglucosidasius HrcA, which is typical of DNA-binding proteins, and indicated that two residues in the HTH motif are crucial for the binding of HrcA to the CIRCE element. Furthermore, we compared the thermostabilities of the HrcA-CIRCE complexes derived from Bacillus subtilis and B. thermoglucosidasius, which grow at vastly different ranges of temperature. The thermostability profiles of their HrcA-CIRCE complexes were quite consistent with the difference in the growth temperatures of B. thermoglucosidasius and B. subtilis and, thus, suggested that HrcA can function as a thermosensor to detect temperature changes in cells.
Amino Acid Sequence↗
Introduction of a board certification system for the Japanese Society of General Hospital Psychiatry.
The importance of board certification systems is increasing in parallel with changes in the social conditions surrounding general medical practice. The same is also the case for consultation-liaison psychiatry, a subspecialty of psychiatry. As a consequence, in April 2001 a board certification system for the Japanese Society of General Hospital Psychiatry was introduced. The clinical abilities required for liaison psychiatrists in this system can be summarized as follows: the ability to adequately treat patients with physical/psychiatric comorbidity or somatization, the ability to form an appropriate and adequate relationship with patients with physical diseases and to collaborate with medical and surgical professionals, and to have a good social and ethical awareness of general medical practice. The conditions required to obtain certification and the issues that remain to be addressed are also discussed.
Certification↗
[Biochemical diagnosis, molecular genetics method].
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Biomarkers↗
[Dose investigation of superparamagnetic iron oxide (SPIO) SH U 555 A in liver MR imaging].
SH U 555 A, a new superparamagnetic iron oxide (SPIO) contrast agent for liver MR imaging, was investigated in terms of safety and efficacy. Eighty-four patients with suspected malignant liver tumor were randomly allocated to two groups: the L dose group (8 mumol Fe/kg) and H dose group (12 mumol Fe/kg). Efficacy was qualitatively evaluated through blinded reading of the MR images. Assessment of the images revealed no consistent differences between the L and H dose groups. During the 3- to 4-day observation period, a total of 16 adverse events were observed in 11 patients: 8 patients in the L dose group and 3 patients in the H dose group. Nasal bleeding occurred in 2 of these cases in the H dose group 2 and 4 days, respectively, after injection. Although patients in the H dose group showed a significantly larger transient decrease in Coagulation Factor XI at 4-6 hr post-injection (p.i.) than patients in the L dose group, analysis of covariance revealed an estimated 6.5% difference. There was no prolongation of APTT or change in Factor XI at 72-96 hr p.i. Because there were no clinically significant differences between the L and H doses, both were considered to be safe and effective.
Aged↗
Norepinephrine transporter density as a causative factor in alterations in MIBG myocardial uptake in NIDDM model rats.
Cardiac scintigraphic studies with iodine-123 labeled metaiodobenzylguanidine ([(123)I]MIBG) have demonstrated global and regionally pronounced decreases in myocardial accumulation of radioactivity in diabetes. The aim of this study was to investigate the cause of the regional differential decrease in accumulation. To this end, we investigated the global and regional myocardial distribution of [(125)I]MIBG in GK/Crj (GK) rats [a model of non-insulin-dependent diabetes mellitus (NIDDM)] and assessed the responsibility of regional myocardial blood flow, myocardial and plasma norepinephrine (NE) content, and norepinephrine transporter (NET) function for the regional variations in [(125)I]MIBG accumulation. To investigate the responsibility of myocardial blood flow for the alterations in MIBG accumulation, dual-isotope autoradiographic studies with [(125)I]MIBG and technetium-99m hexakis-2-methoxy-2-isobutylisonitrile (MIBI), a tracer for the measurement of myocardial blood flow, were carried out in GK rats and control rats. The results in respect of the uptake of radioactivity into various myocardial regions were expressed as distribution absorption ratios [DAR = (radioactivity of tissue/g of tissue) x (body weight/total injected dose)]. In control rats, uptake of [(125)I]MIBG was significantly higher in the inferior wall than in the anterior wall (anterior wall, 6.35 +/- 0.90; inferior wall, 8.12 +/- 1.27: P < 0.001). On the other hand, in GK rats, uptake of [(125)I]MIBG was similar between the anterior wall and the inferior wall (anterior wall, 4.91 +/- 0.71; inferior wall, 4.81 +/- 0.69). Compared with control rats, uptake of [(125)I]MIBG in GK rats was decreased in both the anterior wall and the inferior wall. Uptake of (99m)Tc-MIBI was not significantly different between the anterior and inferior walls in control (anterior wall, 17.9 +/- 4.42; inferior wall, 18.1 +/- 4.52) and GK rats (anterior wall, 16.6 +/-8.03; inferior wall, 16.7 +/- 7.90), indicating that myocardial blood flow did not change regionally in either control or GK rats, and that the blood flow was not responsible for the differential decrease in MIBG accumulation in GK rats. Cardiac and plasma NE levels were measured using an HPLC-electrochemical detection system. The cardiac and plasma NE concentrations were not significantly different between control (anterior wall, 347 +/- 56 ng/g; inferior wall, 354 +/- 31 ng/g; plasma 9.38 +/- 2.10 ng/ml) and GK rats (anterior wall, 323 +/- 62 ng/g; inferior wall, 344 +/- 35 ng/g; plasma, 9.41 +/- 2.39 ng/ml). The density and affinity of NET were investigated by studying the binding of [(3)H]desipramine to cardiac membranes. The B(max) (fmol/mg protein) in the inferior wall was significantly higher than that in the anterior wall in the control rats (anterior wall, 364 +/- 28; inferior wall, 459 +/- 36: P < 0.05). On the other hand, there was no significant difference in the B(max) value between the anterior and inferior walls in GK rats (anterior wall, 263 +/- 42; inferior wall, 251 +/- 27). In conclusion, myocardial MIBG uptake was differentially reduced in GK rats, and this decrease was associated with a decrease in NET density, but the regional myocardial blood flow and the NE concentration were not responsible for the alterations in MIBG uptake. Thus, NET density was identified as the factor responsible for decreases in MIBG accumulation.
3-Iodobenzylguanidine↗
Age-related changes of myocardial norepinephrine transporter density in rats: implications for differential cardiac accumulation of MIBG in aging.
The myocardial regional distribution of [(125)I]MIBG was examined in various aged (7-, 18-, 42-, 47-, and 65-week-old) rats and compared with the effects of regional myocardial blood flow and norepinephrine transporter (NET) function on regional [(125)I]MIBG accumulation in aged rats. In 7- and 18-week-old rats, the accumulation of [(125)I]MIBG was higher in the inferior wall than anterior wall. However, in more than 42-week-old rats, the uptake of MIBG was lower in the inferior wall than that the anterior wall. The uptake of [(99m)Tc]MIBI was greater in the inferior wall than the anterior wall in 18-week-old rats, but was reduced in the inferior wall compared to the anterior wall in 42- and 47- week-old rats. Furthermore, the in vitro binding studies of [(3)H]desipramine to cardiac membranes showed that the B(max) value of NET was larger for the inferior wall than the anterior wall in 7-week-old rats, but was smaller for the inferior wall than the anterior wall in 47-week-old rats. The K(D) values for both walls were significantly larger in 47-week-old than 7-week-old rats. These results indicated that myocardial MIBG accumulation was lower in the inferior wall than the anterior wall of older rats, and that this differential MIBG accumulation in aging was related to the regional changes in myocardial blood flow and NET functions in the inferior wall.
3-Iodobenzylguanidine↗