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Biomedical subjects

K Hoshi

Publications and source records attributed to K Hoshi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Supplemental embolization coil implantation for closure of patent ductus arteriosus in a beagle dog.

Embolization coil for the occlusion of patent ductus arteriosus (PDA) was inserted in a beagle dog diagnosed as PDA with systolic murmur. Residual shunt was observed three months postoperatively and then supplemental coil was inserted. In the past only one coil was required for the closure of PDA in our cases with good post-operative results. In this case, however, the largest coil presently available (8 mm in diameter with 5 loops) was inadequate to make sufficient closure within 3 months postoperatively and supplemental coil insertion was necessary to produce a successful occlusion.

Animals↗
PubMed2001

Localizational alterations of calcium, phosphorus, and calcification-related organics such as proteoglycans and alkaline phosphatase during bone calcification.

To further approach the mechanisms of bone calcification, embryonic rat calvariae were observed at electron microscopic level by the means of fine structures and various cytochemical localizations, including nonspecific proteoglycan (PG) stained by cuprolinic blue (CB), decorin, chondroitin sulfate, hyaluronan, and alkaline phosphatase (ALP), as well as the elemental mapping of calcium (Ca) and phosphorus (P) by energy-filtering transmission electron microscopy (EFTEM). In the calvariae, calcification advanced as the distance from osteoblasts increased. Closer to the osteoblasts, the osteoid was marked by an abundance of CB-positive PGs around collagen fibrils. After crystallization within matrix vesicles, calcified nodules formed and expanded, creating a coherent calcified matrix. The sizes of CB-positive PG-like structures diminished as calcification proceeded. Although small CB-positive structures were accumulated in early stage-calcified nodules, they were localized along the periphery of larger calcified nodules. Cytochemical tests for decorin, chondroitin sulfate, and hyaluronan determined their presence in the areas around collagen fibrils of the osteoid, as well as in and around calcified nodules, whereas ALP was found in the matrix vesicles, as well as in and around the calcified nodules. Ca tended to localize at the PG sites, while P often mapped to the collagen fibril structures, in the uncalcified matrix. In contrast, Ca/P colocalization was visible in and around the calcified nodules, where ALP and smaller CB-positive structures were observed. The difference in the localization patterns of Ca and P in uncalcified areas may limit the local [Ca2+][PO4(3-)] product, leading to the general inhibition of hydroxyapatite crystallization. The downsizing of CB-positive structures suggested enzymatic fragmentation of PGs. Such structural alterations would contribute to the preservation and transport of calcium. ALP possesses the ability to boost local phosphate anion concentration. Therefore, structurally altered PGs and ALP may cooperate in Ca/P colocalization, thus promoting bone calcification.

Alkaline Phosphatase↗
PubMed2001

Targeted disruption of cadherin-11 leads to a reduction in bone density in calvaria and long bone metaphyses.

The migration and adhesion of osteoblasts requires several classical cadherins. Cadherin-11, one of the classical cadherins, was expressed in mouse osteoblasts in skull bone and femur, revealed by immunohistochemistry. To elucidate the function of cadherin-11 in osteoblastogenesis, cadherin-11 null mutant mice were investigated. Although apparently normal at birth, Alizarin red staining of null mutant mice showed a reduced calcified area at the frontal suture that caused a round-shaped calvaria with increasing animal age to 3 months. Consequently, there was a reduction in bone density at the femoral metaphyses and the diploë of calvaria in null mutant mice. In the in vitro culture of newborn calvarial cells, the calcified area of mutant cells was smaller than those derived from wild-type littermates. These results show that absence of cadherin-11 leads to reduced bone density in some parts of skeletons including calvaria and long bone metaphyses, and thus suggest that cadherin-11 plays roles in the regulation of osteoblast differentiation and in the mineralization of the osteoid matrix.

Animals↗
PubMed2001

The novel untranslated exon "exon 0T" encoded between the exon 0 and exon 1 of the rat estrogen receptor alpha (ER alpha) gene.

We have recently isolated two untranslated first exons, exon 0N and exon 0S, of rat estrogen receptor alpha (ER alpha) gene from the liver by use of 5'-rapid amplification of the cDNA ends (5'-RACE) method. In this communication, we further analyzed the 5'-untranslated region (UTR) of the ER alpha mRNA in rat anterior hypophysis in order to investigate the existence of the other 5'-untranslated exon(s) of rat ER alpha gene. Total RNA from the anterior hypophysis of 8-week-old female Wistar strain male rats was subjected to 5'-RACE with antisense primers located in exon 1 of the rat ER alpha gene and one of the positive clones (clone 35) was sequenced. The nucleotide sequence of clone 35 revealed the insertion of a previously unidentified exon (which we termed "exon 0T") between exon 0 (the first reported 5'-UTR form of rat ER alpha mRNA) and exon 1 of rat ER alpha mRNA. Analysis of rat genomic DNA indicated that exon 0T was located between exon 0 and exon 1 of rat ER alpha gene. We further investigated the distribution of ER alpha mRNA containing exon 0T in several brain regions and various peripheral tissues of 8-week-old male and female Wistar strain rats by use of reverse transcription-polymerase chain reaction (RT-PCR). The distribution of the ER alpha mRNA (0T-1) was essentially similar to that of ER alpha mRNA in which exon 0 was spliced onto exon 1 reported previously. These results indicate that (1) exon 0T is a novel untranslated exon of rat ER alpha gene which is located between exon 0 and exon 1 on rat genomic DNA, (2) exon 0T is inserted between exon 0 and exon 1 of ER alpha mRNA by alternative splicing, and (3) this alternative splicing may occur in tissues where the transcription of ER alpha gene is initiated from exon 0.

5' Untranslated Regions↗
PubMed2001

Differences in respiratory parameters during continuous positive airway pressure and pressure support ventilation in infants and children.

The extubation criteria of pressure support ventilation (PSV) in infants and children were not yet established. We studied the differences in respiratory parameters during continuous positive airway pressure (CPAP) using a constant flow type ventilator and PSV using a demand valve type ventilator. Nineteen children (1.9+/-2.9 years old) who were ready to extubate were studied. All patients had recovered from their respiratory failure and had finished the weaning process of the ventilatory support. They were scheduled for extubation on the next day when their ventilatory mode had attained to a PSV of 3 cmH2O with a positive end-expiratory pressure (PEEP) of 3 cmH2O. On the extubation day, tidal volume (TV) and respiratory frequency (RR) were measured with a respiratory monitor at two modes (CPAP of 3 cmH2O and PSV), and the duty ratio (DR) and mean inspiratory flow (MF) were calculated. The sequence of the ventilatory mode was random. No case required reintubation. TV was 61.6+/-54.9 during CPAP and 67.7+/-61.4 ml during PSV, and RR was 38.5+/-10.6 and 37.1+/-8.8 beats/min., respectively. DR was 0.382+/-0.067 and 0.359+/-0.085, and MF was 96.6+/-78.3 and 101.0+/-69.0 ml/sec., respectively. The measured parameters and calculated values showed no significant difference between CPAP and PSV. It was found that the respiratory parameters were almost the same with CPAP and PSV immediately before the extubation, and the previous extubation criteria of CPAP can be used.

Blood Gas Analysis↗
PubMed2001

Evaluation of tube compensation in the Bennett 840 ventilator--a new ventilatory mode to support spontaneous breathing.

Respiratory care patients frequently require intubation with an endotracheal tube (ETT). Unfortunately, the ETT introduces a pressure drop (deltaPETT) that depends on the respiratory flow rate, thus increasing the work of breathing (WOB). Pressure support ventilation (PSV) cannot adequately compensate for this added WOB, because the degree of inspiratory assistance by PSV is fixed. Therefore, a technique called tube compensation (TC) has been developed to address deltaPETT. We examined the performance of TC and compared it with PSV of 5 cm H2O. The experimental system was constructed from a simulator, a test-lung, flow sensors, and a Bennett 840, and the respiratory parameters were studied. ETTs with IDs 6.5 and 8.0 mm were used. The quadratic approximation obtained for deltaPETT in the 6.5-mm ETT was 2.316 x flow + 7.910 x flow2, while that for the 8.0-mm ETT was 1.881 x flow + 3.353 x flow2. The maximum inspiratory flow (MIF) increased significantly with increasing TC, but tidal volume and inspiratory time did not show marked changes. The MIF for TC of 100% was larger than that for PSV of 5 cm H2O, when the 6.5-mm ID was used, but there was no significant difference between these modes when an ID of 8.0 mm was used. For both the 6.5 and 8.0-mm IDs, the PV loop corresponding to 100% TC was larger than that for PSV of 5 cm H2O. TC only compensated for the WOB caused by the ETT, whereas PSV compensated for the WOB caused by the ETT and the demand valve system. In clinical use, the differences between TC and PSV will demand attention.

Humans↗
PubMed2001

Histopathological characterization of melorheostosis.

Melorheostotic bone was examined histopathologically. In the severely affected areas, an abundance of osteoid and increased angiogenesis was observed. Increased osteoid without mineralization indicated the overproduction of bone matrix. Bone resorption also appeared to increase because osteoclasts were numerous in melorheostotic bone, thus suggesting a high rate of bone turnover. In addition, transforming growth factor-beta was immunolocalized in the periosteal fibroblasts, mesenchymal cells surrounding vessels, endothelial cells, and osteoblasts, while basic fibroblast growth factor was found in endothelial cells and mast cells near vessels. These cytokines may have some association with the exuberant bone matrix production and angiogenesis in melorheostosis.

Adult↗
PubMed2001

[A multicenter cross-sectional study on the Health Related Quality of Life of patients with rheumatoid arthritis using a revised Japanese version of the Arthritis Impact Measurement Scales Version 2 (AIMS 2), focusing on physical disability and its associative factors].

OBJECTIVE: A multicenter cross-sectional survey was conducted to study the current status of Health Related Quality of Life (HRQL) of Japanese patients with rheumatoid arthritis using a revised Japanese version of the AIMS 2, to investigate the association among the self-report physical disability scores and demographic, socioeconomic, and clinical variables in these patients. METHODS: A Japanese version of the AIMS 2 was administered to the randomly chosen 1614 patients with classical and definite rheumatoid arthritis attending arthritis clinics at eleven hospitals across the country. Self-report functional disability scores (FDSs) were calculated, by which patients were classified into five groups with graded levels of disability. Univariate correlations were examined between FDSs and the scores of the other four components of AIMS-HRQL, disease duration, age, medical costs, and physical and laboratory measures. Analysis of variance was performed to test for among level differences of these variables in each group of patients. Mean values and standard deviations of FDSs were calculated and analysis of variance was used to test for among level differences of the following factors: demographic, socio-economic, clinical measures, and treatment status. RESULTS: Among four scales composing the AIMS 2-HRQL, work disability scores were most strongly correlated with FDSs, followed by the scores of pain, affection and social interaction. The more severely disabled group proved to have weaker grip strength, higher joint count, longer disease duration, higher ESR and blood level of CRP, and lower level of Hb. Patients with more disabilities proved to be older, pay more medical costs, have longer duration of morning stiffness, and higher level of RF. Patients with more advanced Steinbrocker's functional class, doctor's global assessment, Steinbrocker's anatomical stage, higher daily dose of prednisolone intake, lower level of annual income and formal education, and patients taking more kinds of NSAIDs proved to be more severely disabled. Separate, single (never married, widowed), and divorced patients proved to be more severely disabled compared with married ones. Overall, females were more disabled than males. CONCLUSION: Physical disability is associated with the other important aspects of QOL, clinical signs and symptoms, and socio-economic conditions in RA patients. Prevention and management of physical disability should be seriously planned in consideration of the changes in these conditions in RA patients.

Arthritis, Rheumatoid↗
PubMed2001

[Rheumatic pain].

RA is a chronic inflammatory arthropathy that characterized by joint destruction with invasive proliferation of synovial cells in articular cartilage. Inflammatory cytokines like TNF-alpha, IL-1 and IL-6 are overproduced and play an important role in the process. In order to relief patient's chronic pain and to prevent of joint destruction, NSAIDs, steroids and DMARDs are common. Recently, anti-cytokine therapy develop and neutralizing antibody to TNF-alpha (infliximab) and TNF-alpha receptor/IgG fusion protein(etanercept) are already used in U.S.A. and in Europe. In Japan, these medicines are now on clinical trial and will be available in a few years. Other anti-cytokine therapy like IL-1 receptor antagonist and anti-IL-6 receptor antibody is also on clinical trial.

Anti-Inflammatory Agents↗
PubMed2001

[A case of ovarian cancer with metastatic tumor in the liver with paclitaxel and carboplatin systemic chemotherapy was very effective].

An 82-year-old woman was admitted to the Dept. of Obstetrics and Gynecology, Yamanashi Medical University to try to identify the origin of a liver metastatic tumor. CT examination revealed a small tumor located adjacent to the uterine cervix in a cul-de-sac. With biopsy using MR, it was clearly shown histologically that the origin of the tumor was the ovary. Systemic chemotherapy with paclitaxel and carboplatin was selected as the most reasonable treatment for this case because of the patient's age. After 6 courses of this chemotherapy, the tumor in the cul-de-sac disappeared and the tumor in the liver decreased markedly. Furthermore, no severe side effects were seen during this treatment. This result indicated that systemic chemotherapy with paclitaxel and carboplatin is effective and safe in cases of advanced ovarian cancer.

Adenocarcinoma↗
PubMed2001

Ultrastructural analysis of bone calcification by using energy-filtering transmission electron microscopy.

In order to elucidate the mechanisms of bone calcification, embryonic rat calvariae treated with chemical or cryo-fixation were observed using transmission electron microscopy by three techniques: fine structures, various cvtochemical localizations including nonspecific proteoglycan, decorin, chondroitin 4-sulfate, hyaluronan, alkaline phosphatase (ALP), and osteonectin, as well as the elemental mapping of calcium and phosphorus by energy-filtering electron microscopy. In the calvariae, the calcification sequence ran as follows crystallization within matrix vesicles, formation of calcified nodules, collagen calcification, and finally the establishment of an expansive calcified matrix. The osteoid contained an abundance of mesh-like fibers of proteoglycans, including decorin, chondroitin 4-sulfate, and hyaluronan, around collagen fibrils approximately 50 nm in diameter. Calcium tended to localize at the proteoglycan sites, while phosphorus was often mapped to the collagen fibril-structures in the osteoid. Calcium/phosphorus co-localization was found in and around the calcified nodules, where ALP and small sized proteoglycans were observed. During this stage, native proteoglycans surrounding the collagen fibrils disappeared, with the collagen fibrils fusing laterally, and attaining a diameter of more than 400nm. The calcified nodules expanded to occupy the entire space made available by the collagen fibril-fusion, following osteonectin accumulation in the calcified nodule/collagen fibril border. In conclusion, crystals present within the matrix vesicles became calcified nodules, in a process induced by the co-localization of calcium and phosphorus. ALP and proteoglycans may participate in the calcium/phosphorus co-localization. Decreases in the native proteoglycans, and the lateral fusion of collagen fibrils are thought to be involved in the expansion of calcified areas, followed by osteonectin-mediated collagen calcification.

Alkaline Phosphatase↗
PubMed2000

Regional expression of a gene encoding a neuron-specific Na(+)-dependent inorganic phosphate cotransporter (DNPI) in the rat forebrain.

We have analyzed expression of a gene encoding a brain-specific Na(+)-dependent inorganic phosphate cotransporter (DNPI), which was recently cloned from human brain, in rat forebrain using in situ hybridization. The expression of DNPI mRNA showed a widespread but highly heterogeneous pattern of distribution in the forebrain, where hybridization signals were observed in neurons but not in any other types of cells. Neurons expressing the mRNA were far more numerous in the diencephalon than in the telencephalon. In the thalamus, a number of neurons with high levels of signals were localized to all nuclei of the dorsal thalamus, habenular nuclei and subthalamic nucleus, but not the reticular nucleus and zona incerta. Moderate signal levels were seen in many neurons throughout the hypothalamus, particularly the ventromedial, paraventricular, supraoptic and arcuate nuclei, lateral hypothalamic area and mammillary complex. In contrast, expression of DNPI mRNA in the telencephalon was generally at a low level and occurred locally in some restricted regions within the neocortex, retrosplenial cortex, piriform cortex, olfactory regions, hippocampal formation and medial amygdaloid nucleus. The present results suggest that DNPI functions in heterogeneous neuron populations as a neuron-specific Na(+)-dependent inorganic phosphate cotransport system predominantly expressed in the diencephalon of the rat.

Animals↗
PubMed2000

Creutzfeldt-Jakob disease associated with cadaveric dura mater grafts in Japan.

A nationwide survey and recent information documented 57 patients with Creutzfeldt-Jakob disease (CJD) who had received dura mater grafts during the period between January 1979 and September 1999. At least 54 of these 57 patients received the same brand of dura mater graft from the same processor. Mean age at disease onset in the 57 patients with dural grafts was younger (51.9 years) than that in patients with sporadic CJD (63 years) (p < 0. 0001). Initial symptoms were cerebellar ataxia, disorientation, and visual or oculomotor disturbance.

Cadaver↗
PubMed2000

Air embolism in the right coronary artery occurring during the left coronary angioplasty using the guiding catheter with a side hole.

Coronary air embolism is one of the inadvertent complications of coronary angioplasty. We report two rare cases of complicating air embolism in the right coronary artery occurring during control left coronary angiography using a guiding catheter with a side hole, just prior to a coronary intervention procedure for a left coronary artery lesion. The air seemed to be injected into the right coronary artery through the side hole. When we use an angiographic or guiding catheter with a side hole, we should be aware that an air embolism can occur in the contralateral coronary artery and should carefully and repeatedly perform aspiration of the catheter.

Aged↗
PubMed2000

Radical scavenging properties of novel benzopyran derivatives, TA248 and TA276, and effects of the compounds on ischemic/reperfused myocardium in dogs.

Characteristics of novel benzopyran derivatives, TA248 and TA276, and their effects on myocardial contraction in ischemic/reperfused hearts in dogs were examined. TA248 and TA276 inhibited NADPH-dependent lipid peroxidation induced by Fe(3+) in the rat brain homogenate. Both compounds reduced *O(2-) produced by xanthine-xanthine oxidase system in a dose-dependent manner. TA276 scavenged.OH generated by Fenton reaction in a dose-dependent manner. TA248 also inhibited the.OH production, but the effect was neither complete nor dose dependent. Myocardial contraction was assessed as segment shortening of the left ventricular wall in pentobarbital-anesthetized open-chest dogs. The segment shortening was decreased by the left anterior descending coronary artery ligation (ischemia) and returned by release of the ligated artery (reperfusion). The segment shortening did not recover fully during reperfusion. Either TA248 or TA276 injected 10 min before ischemia improved the recovery of myocardial contraction during reperfusion. Both compounds preserved the level of ATP in the 60-min reperfused myocardium. However, the level of lipid peroxides was not changed by TA248 and TA276. TA248 and TA276 may protect myocardium against ischemic/reperfusion insult, partly because of their free radical scavenging activity, but no significant change in myocardial lipid peroxide level was observed.

Animals↗
PubMed2000

Excitatory amino acid release in the locus coeruleus during naloxone-precipitated morphine withdrawal in adjuvant arthritic rats.

OBJECTIVE AND DESIGN: Excitatory amino acid levels in the locus coeruleus (LC) and the behavioral signs during naloxone-precipitated withdrawal in arthritic rats treated with chronic morphine were investigated by in vivo microdialysis. METHODS: Increases in glutamate (Glu) and aspartate (Asp) were noted after naloxone (48 nmol/5 microl, LC)-precipitated withdrawal from normal and adjuvant arthritic rats which had been intracerebroventricularly infused for 3 days with morphine (26 nmol/l microl/h). RESULTS: The increases in Glu and Asp levels on morphine withdrawal in normal rats were attenuated following naloxone challenge in the morphine-dependent arthritic rats. Moreover, behavioral signs during morphine withdrawal were detected following the naloxone challenge in both the morphine-dependent normal and adjuvant arthritic rats, but not in the saline-infused controls. CONCLUSIONS: These results show that the attenuation of Glu and Asp release from the LC in the adjuvant arthritic rats might explain the anti-inflammatory and analgesic effects of mu-opioids in adjuvant arthritic rats.

Animals↗
PubMed2000

Matrix vesicle calcification in bones of adult rats.

To clarify the calcification mechanism that functions in bone formation in adult rats, the ultrastructure of tibial trabeculae and calvarial endostea obtained from 8- to 18-month-old rats was investigated morphologically, and compared with that of 19.5-day post-coitum fetal rats. In both samples, osteoid was observed between the activated osteoblasts and the calcified matrix, which contained matrix vesicles enclosed by a biological membrane. Some of these vesicles contained needle-like crystals thought to be hydroxyapatite, suggesting probable matrix vesicle calcification. These results indicate that matrix vesicle function not only in the initial calcification that occurs during embryonic ossification but also contribute to bone formation in adults.

Animals↗