Biomedical subjects

Y Okazaki

Publications and source records attributed to Y Okazaki.

At least 127 records · Page 7Linked to original sources

PubMed1998

Vascular leiomyoma of the mesentery in a dog.

A 4-year-old male, miniature Schnauzer dog showed two large masses in the mesentery at necropsy. Histological examination of both masses revealed plain smooth muscle tumour cells intermingled with thick-walled blood vessels. The bundles of tumour cells often extended from the periphery of the vessels. Mitotic figures were rare. From these findings, the tumour was diagnosed as a vascular leiomyoma (angiomyoma), previously unreported in animals. The term, vascular leiomyoma, was proposed to describe this tumour in order to avoid confusion with hamartomatous angiomyoma.

Actins↗

PubMed1998

Corrosion resistance, mechanical properties, corrosion fatigue strength and cytocompatibility of new Ti alloys without Al and V.

The effects of various metallic ions using various metallic powders on the relative growth ratio of fibroblasts L929 and osteoblasts MC3T3-E1 cells were carried out. Ti, Zr, Sn, Nb and Ta had evidently no effect on the relative growth ratios of cells. Otherwise, Al and V ions exhibit cytotoxicity from a concentration of > or = 0.2 ppm. This Al effect on cells tend to be stronger in medium containing small quantity of V ions (< or = 0.03 ppm). The new Ti-15%Zr-4%Nb-4%Ta-0.2%Pd alloy exhibited a higher corrosion resistance in physiological saline solution. The addition of 0.02%O and 0.05%N to Ti-Zr alloy improved the mechanical properties at room temperature and corrosion fatigue strength. The relative growth ratios for the new Ti alloy plate and the alloy block extraction were unity. Further, the relative growth ratios were almost unity for the new Ti alloy against apatite ceramic pins up to 10(5) wear cycles in Eagle's MEM solution. However, there was a sharp decrease for Ti-6%Al-4%V ELI alloy from 3 x 10(4) wear cycles as V ion was released during wear into the wear test solution since the pH of the Eagle's MEM increases with increasing wear cycles.

3T3 Cells↗

PubMed1998

Effects of a weekly injection of human parathyroid hormone (1-34) and withdrawal on bone mass, strength, and turnover in mature ovariectomized rats.

One hundred fifteen Wistar rats, 7 months of age, were ovariectomized (ovx) or sham-operated to evaluate the effects of a weekly injection of human parathyroid hormone (hPTH) and withdrawal on the bone mass, strength, and turnover in mature ovariectomized rats. At 3 months, ovx rats were given a weekly injection of hPTH(1-34) at the respective doses of 0 (vehicle), 10, and 90 microg/kg body weight (BW) for 3 months. Then, hPTH-treated rats were divided into two groups each: continuously treated groups, and the groups treated with vehicle only for another 3 months. Weekly hPTH injections at doses of 10 or 90 microg/kg BW maintained the lumbar BMD values and increased the values of the femoral cortical bone, increasing the bone formation rates in the trabecular, endocortical, and periosteal envelopes. Trabecular osteoclasts were increased in the 90 microg/kg dose group. Trabecular bone surface relative to the volume was decreased by hPTH. The compressive load of the lumbar bone and the bending moment of the midfemur were increased. The lumbar compressive load values, corrected for BMD and volume, and the moment of inertia of the midfemur were also increased. The intracortical porosity values were not increased by the treatment. After withdrawal of hPTH treatment, the BMD values in both the lumbar and the midfemur were reduced to ovx control levels. The bone mass stimulated by the 90 microg/kg dose was reduced faster than that by the 10 microg/kg dose. However, the parameters of bone strength were still larger than those of the ovx controls after cessation of the hPTH treatment. Thus, a weekly hPTH injection effectively stimulated the bone formation in both the trabecular and cortical bone, leading to positive effects on mass and structure of the bone. These data suggest the possibility of benefits of both a lower frequency of hPTH injections as well as high-frequency injections for human osteoporotics.

Absorptiometry, Photon↗

PubMed1998

Prednisolone prevents decreases in trabecular bone mass and strength by reducing bone resorption and bone formation defect in adjuvant-induced arthritic rats.

We examined the effects of prednisolone (PSL) administration in normal female Sprague Dawley rats and adjuvant-induced arthritic rats at the age of 6 weeks. Rats were intramuscularly injected with PSL twice a week at doses of 0 (control), 10, 30, 90, or 270 mg/kg body weight (b.w.). In the normal rats, serum osteocalcin level at 14 days and serum carboxyterminal pyridinoline cross-linked telopeptide of type 1 collagen (1CTP) level at 28 days in the 270 mg/kg dose group was lower than the respective value in control animals. The BMC and the trabecular bone formation rate (BFR/BS) of the lumbar body (L-4) in the 270 mg/kg dose group at 14 and 28 days were significantly lower than the values in the control rats. In the arthritic rats, however, serum osteocalcin levels in the PSL-treated groups did not differ compared with arthritic controls. The serum 1CTP levels in all of the PSL-treated groups were significantly reduced at 28 days. The age-dependent increases in the L4 BMC, BMD, and L-3 ultimate compressive load values were maintained. The BFR/BS values in the 90 mg/kg and 270 mg/kg dose groups were significantly higher than those in the arthritic control rats. The trabecular osteoclast number and surface values in all of the PSL-treated groups were significantly lower than the values in arthritic controls. These data demonstrate that PSL administration prevented reduction in bone mass and strength of the lumbar trabecular bone in adjuvant-induced arthritic rats by reducing the increase in bone resorption and the decrease in bone formation at both the local and systemic levels.

Animals↗

PubMed1998

Bone marrow cell development and trabecular bone dynamics after ovariectomy in ddy mice.

To clarify the relationship between the sequential changes of trabecular bone turnover and bone marrow cell development in ovariectomized (ovx) mice, bilateral tibiae of 8-week-old ddy mice were obtained. Histomorphometric analyses of the trabecular bone of the proximal tibia of ovx mice revealed increases in the bone formation rate and the osteoclast surface for the first 28 days postovariectomy. The trabecular bone volume showed a rapid decrease for the first 28 days and a steady state for the subsequent 14 days. In bone marrow cell culture experiments, the numbers of total and nonadherent bone marrow cells per tibia obtained from the ovx mice increased. The formation of osteogenic nodules and osteoclast-like multinucleated cells in the marrow cultures obtained from ovx limbs showed a significant increase on days 14 and 28 and returned to the sham-operated level by day 42. The numbers of colony forming units (fibroblastic) and colony forming units (granulocytes and macrophages) that developed from the marrow cells did not differ between the ovx and sham limbs at any time during the study period. Fluorescence-activated cell-sorter analysis revealed no population changes in the cell development of macrophages. These results demonstrate that there are two stages in the development of osteopenia after ovx. During the first 28 days after ovx, the ovariectomy enhances the developmental process from bone marrow stromal cells to osteoblasts and the terminal differentiation from osteoclast precursors to mature osteoclasts. The trabecular bone turnover also increases. In the subsequent 14 days, the changes in the osteogenic and osteoclastogenic potentials of the bone marrow cells are alleviated and the trabecular bone dynamics are in a steady state. The changes in bone marrow cell development are closely associated with those at the trabecular bone surface.

Animals↗

PubMed1998

Patterns of care study of radiation therapy for cervix cancer in Japan: the influence of the stratification of institution on the process.

BACKGROUND: To improve the quality of radiation oncology in Japan, Patterns of Care Study (PCS), a widely known quality assurance (QA) program in the USA, was introduced. The feasibility was tested by collecting nationwide data by extramural audit for cervix cancer. METHODS: From July 1996 through February 1997, PCS audits were performed for 29 institutions nationwide. On the basis of the facility survey by Tsunemoto, 13 institutions were classified as A1 (university hospital/cancer center), 10 as B1 (other institutions treating >120 patients/year) and six as B2 (other institutions treating <120 patients/year). Medical charts for the patients treated for cervix cancer between 1992 and 1994 were reviewed based on the data format of the US PCS. The total number of patients surveyed was 432. RESULTS: Simulation was used for >90% of the patients in both A1 and B1-2 institutions. However, in B1-2, planning for 5% of the patients was performed with only a clinical set-up (p = 0.0287). A daily fraction with a size of 200 cGy was given to >65% of patients in A1 and to <47% in B1-2. On the other hand, >50% of those in B1-2 were treated with daily fractions of 180 cGy and less compared with 25% in A1 institutions (p < 0.0001). Brachytherapy was utilized more frequently for patients in Stages II (p = 0.0365), III (p = 0.0015) and IV (p = 0.0483) in A1 than in B1-2. As for external beam equipment, linear accelerators with 10 MV or more were used for 83% of the patients in A1. However, in B1-2 institutions, machines with lower energy were used for 38% of the patients (p < 0.0001). The median number of full-time-equivalent (FTE) radiation oncologists was 2.7 in A1, 0.65 in B1 and 0.2 in B2. CONCLUSIONS: Institutional stratification, including equipment and personnel, was found to affect significantly the patterns of care for cervix cancer. Therefore, to improve the quality of radiation therapy nationwide, improvements in equipment and in supply of FTE personnel are extremely important. PCS was found to have great potential for a practical evaluation of how much improvement will be required in Japan.

Adult↗

PubMed1998

Morphological brain imaging studies on major psychoses.

The first application of computed tomographic scan to the schizophrenic brain by Johnstone et al. initiated a new neuroscience research era with new perspectives on the neurobiological aspects of major psychoses. The most common paradigm in the flurry of brain imaging studies following the first report was the case-control study comparing controls and patients with major psychoses. However, some application was also made of sophisticated case-control paradigms, such as comparisons between affected and non-affected identical twins discordant for schizophrenia. Very few prospective cohort studies have been applied in this field. During the past two decades of studies, several brain morphological features have converged. Both schizophrenics and patients with affective disorders showed subtle but significant quantitative differences in brain structures compared with controls. For schizophrenia, the differences were in the lateral and third ventricles, medial temporal lobe, supratemporal gyrus, frontal lobe and such subcortical nuclei as striatum and thalamus. For affective disorders, they were in the cortical sulci, lateral ventricle, striatum, pituitary and adrenal glands. Generally, the differences were greater in schizophrenics, in males and on the left side than in patients with affective disorders, in females and on the right side. Qualitative morphological abnormalities such as T2-weighted hyperintensity were also demonstrated in elderly patients with affective disorders. For both schizophrenia and affective disorders, abnormal anatomical neurocircuit models of the respective pathophysiologies have been proposed to explain the brain multi-lesions. Some recommendations for future research in the structural brain imaging of major psychoses have also been proposed.

Bipolar Disorder↗

PubMed1998

A new intermaxillary fixation method using adhesive cast splints for avoiding skin puncture.

Intermaxillary fixation using arch bars is performed for mandibular and maxillary fractures. They are applied to the respective maxillary and mandibular arches with circumdental stainless steel wires. Skin puncture may pose a risk for the surgeon. Therefore, the authors have developed and tested a method for using intermaxillary fixation using an adhesive cast splint. The resulting strength was found to be generally superior to that achieved with arch bars. Despite some problems, this technique is considered a useful method for avoiding skin puncture.

Adhesives↗

PubMed1998

Genomic discordance between monozygotic twins discordant for schizophrenia.

OBJECTIVE: Genomic DNA of monozygotic twins discordant for schizophrenia was analyzed to determine whether their genomes were truly identical. METHOD: The subjects were monozygotic male twins, one of whom had DSM-III-R schizophrenia, undifferentiated type. Genomic DNA was extracted from leukocytes and was applied to restriction landmark genome scanning analysis, which was developed for a high-speed survey of restriction sites throughout a genome and measurement of their copy number in each locus. RESULTS: After comparisons of patterns with approximately 2,000 spots, the authors detected at least two spots with autoradiographic intensities that obviously differed in the two twins. CONCLUSIONS: The discrepancies likely were generated either by differences in the methylation status at NotI sites between the twins or by submicroscopic changes occurring at NotI-flanking sites in one twin after (or simultaneous with) twinning. In either case, the difference may influence the transcription level of one or more genes.

Adult↗

PubMed1998

Responses of trabecular and cortical bone turnover and bone mass and strength to bisphosphonate YH529 in ovariohysterectomized beagles with calcium restriction.

Thirty-six beagles, 18 months of age, underwent ovariohysterectomy (OHX) or a sham operation. Sham-operated animals were given a diet with standard calcium (1.4%) (group 1, n = 6) or a restricted calcium diet (0.14%) (group 2, n = 6). The OHX animals were given the restricted calcium diet and YH529 orally with respective daily doses of 0, 0.02, 0.1, and 0.5 mg/kg of body weight (groups 3-6, n = 6 each) for 12 months. At the end of this period, the lumbar bone mineral densities (BMDs) in groups 2 and 3 and the load values for group 3 were significantly smaller than those for group 1. The midfemur BMD did not differ among the groups. The urinary deoxypyridinoline (U-Dpy) and bone formation rates (BFR/BS, BFR/BV) in groups 2 and 3 and the osteonal BFR/BS and trabecular osteoclast number (Oc.N/BS) in group 3 were significantly larger than the respective values for group 1. However, these parameters did not significantly differ between groups 2 and 3. The serum osteocalcin (OC) level, wall thickness (W.Th), and mineral apposition rate values for group 3 were significantly larger than those for group 2. In group 2, the trabecular activation frequency (Ac.F) increased by 3.11 times, and the percent values of the number of labeled osteons (L-Ot.N/T-Ot.N, %) in the tibia by 3.28 times over those for group 1. In group 3, the Ac.F increased by 3.20 times and the number of labeled osteons by 3.77 times over those for group 1. In groups 4-6, the U-Dpy and Oc.N/BS values were smaller, but their OC levels did not significantly differ from the level for group 3. The lumbar BMD, the load, and W.Th were dose-dependently significantly larger than those for group 3. The Ac.F values were significantly smaller, and the respective value in groups 4-6 was 67.9, 25.5, and 10.2% of that in group 3. The BMDs of the midfemur in groups 4-6 were significantly larger than those in group 3, but the ultimate load values did not significantly differ. The L-Ot.N/T-Ot.N values were also significantly smaller, and the respective value in groups 4-6 was 82.0, 48.5, and 55.2% of that in group 3. The tibial endocortical and periosteal BFR/BSs did not differ significantly. These data demonstrate that the effects of OHX on bone mass and turnover were small in the beagles fed a restricted calcium diet. YH529 maintained the mass and strength of the lumbar bone by reducing the bone resorption. The cortical bone appeared to be less sensitive to the agent than the trabecular bone in this animal model.

Administration, Oral↗

PubMed1998

Stability of metallothionein isoforms by capillary zone electrophoresis.

Stability of isoforms on storage of metallothionein (MT) was investigated by capillary zone electrophoresis (CZE) at neutral pH. The mouse liver was removed 1 day after injection of zinc, and homogenized in 0.25 M sucrose with 100 mM TRIS-HCl buffer, pH 7.4. The specimens for MT analysis were obtained by two partial purification methods, i.e., heat treatment (HT) and ethanol/chloroform precipitation (ECP) methods. The specimens were stored at either 4 degrees C or -80 degrees C for 1 and 3 days, and peak areas of MT-1 and MT-2 isoforms obtained by CZE were compared. When specimens were obtained by HT method, both MT isoforms were stable at -80 degrees C within 3 days. However, the peak area of MT-1 stored at 4 degrees C was gradually decreased to one third on the 3rd day. The MT-2 peak did not decrease the next day, but decreased to 57% on the 3rd day. In contrast, peak areas of both MT isoforms decreased remarkably the 1st day, when specimens obtained from ECP method were stored at 4 degrees C and -80 degrees C. From these results, we conclude that stability of MT isoforms is different depending on the purification methods, and MT isoforms are not stable after partial purification, especially by ECP method, even if stored at -80 degrees C.

Animals↗

PubMed1998

Aortic complications after aortic valve replacement in patients with dilated ascending aorta and aortic regurgitation.

BACKGROUND AND AIMS OF THE STUDY: Postoperative aortic complications of aortic dissection or enlargement of the ascending aortic develop in patients with aortic valve replacement (AVR) and dilated ascending aorta. This clinical study aimed to demonstrate the incidence of aortic complications after AVR in patients with dilated ascending aorta, and to clarify the surgical indication and approach for dilated ascending aorta and aortic regurgitation. METHODS: A total of 82 patients who underwent AVR between 1985 and 1997 were allocated to two groups according to the preoperative diameter of the ascending aorta. A dilated ascending aorta with diameter > or = 40 mm was seen in 38 patients (group I), and a small ascending aorta with diameter < 39 mm in 44 patients (group II). Group I patients were further allocated to two subgroups: 12 patients underwent aortoplasty (group IA) and 26 did not (group IB). Event-free rates of aortic complications and survival rate were compared between groups I and II. RESULTS: Postoperative aortic dissection during the follow up period occurred in four hypertensive patients in group I (one in group IA, three in group IB); no aortic dissection was seen in group II. Freedom from all aortic complications at 10 years after surgery was 75 +/- 10% in group I and 100% in group II (p < 0.05). The cumulative survival rate at 10 years was 59 +/- 11% in group I (group IA: 71 +/- 18%, group IB: 51 +/- 14%) and 95 +/- 4% in group II (p < 0.05). CONCLUSIONS: Patients with a dilated ascending aorta (> or = 40 mm diameter) were more likely to encounter complications of the aortic dissection or enlargement after AVR than those with a small ascending aorta. Surgery to prevent aortic dissection or enlargement must be selected in patients with mildly dilated ascending aorta and hypertension.

Adult↗

PubMed1997

A novel control system for polymerase chain reaction using a RIKEN GS384 thermalcycler.

We have developed a novel high-throughput thermalcycler, the RIKEN GS384, which has a maximum of 1536 wells and whose temperature can be controlled accurately and simultaneously for a very small volume of a reaction mixture. In practice, the reaction is carried out using four 384-well (3.5 mm in diameter) plate formats which can be automatically moved using a robotic arm. To achieve accurate temperature control with high thermo-conductivity, we adopted Teflon-coated aluminum well plates closely sandwiched between silicon sheet-covered lids on top and a graphite sheet below. The lids were kept at a higher temperature (2 to 5 degrees C) than the reaction wells. The temperature of the 1536 sample wells was controlled accurately without temperature variability among the wells or evaporation, even for samples of very small volume (minimum 2 microliters). We also developed a new type of plate format which is similar to the 384-well place in terms of plate size, shape, and material, but which differs in the number (1536) and size (1.6 mm in diameter) of the wells. Since the amplification reactions could be done precisely as well, a total of 6144 reactions can potentially be carried out simultaneously using the GS384 thermalcycler. This is very promising for DNA microfabrication technology. This thermalcycler offers the advantage of high-throughput DNA analysis which should be useful for DNA diagnoses or for the human genome project.

Humans↗

PubMed1997

A novel acyl-CoA thioesterase enhances its enzymatic activity by direct binding with HIV Nef.

In addition to playing a crucial role in the pathogenesis of AIDS, HIV nef induces down-regulation of CD4 expression and TCR signaling and also regulates the sorting pathway in host T cells. To elucidate the Nef function in HIV progression, we searched for a cellular component which interacts with Nef. A human cDNA encoding a novel acyl-CoA thioesterase (hACTE-III) was isolated as an HIV nef-binding protein by yeast two-hybrid system. hACTE-III is homologous to E. coli thioesterase II but to none of the mammalian thioesterases and therefore belongs to a new type. hACTE-III exhibits enzymatic specificity for a broad range of fatty acyl-CoAs. The hACTE-III-binding region within Nef is localized in the central region (amino acids 109-152). hACTE-III greatly enhances its enzymatic activity upon direct binding to Nef. Considering that either Nef-overexpression or impaired fatty acid regulation induces alteration of subcellular morphology, the augmented hACTE-III function by Nef-binding might induce dysfunction of T cells.

Amino Acid Sequence↗

PubMed1997

Restriction landmark genomic scanning (RLGS-M)-based genome-wide scanning of mouse liver tumors for alterations in DNA methylation status.

Restriction landmark genomic scanning for methylation (RLGS-M) was used to detect, and subsequently clone, genomic regions with alterations in DNA methylation associated with tumorigenesis. Use of a methylation-sensitive enzyme for the landmark cleavage allows analysis of changes in methylation patterns. In this study, we used RLGS-M to analyze SV40 T antigen-induced mouse liver tumors derived from interspecific F1 hybrids between Mus spretus (S) and C57BL/6 (B6). Because 575 S- and B6-specific RLGS loci/spots have been mapped, tumor-related alterations in the RLGS profile could be immediately localized to specific chromosomal regions. We previously found that the loss of contiguous loci/spots could be attributed primarily to DNA loss, whereas loss of solitary loci/spots could be attributed primarily to DNA methylation. In this study, we examined 30 mouse liver tumor samples for loss of the 507 mapped loci/spots. Fourteen solitary loci/spots found to be absent or reduced in more than 75% of tumor samples were cloned and subjected to DNA sequence analyses. Two loci were identified as alpha4 integrin and p16/CDKN2, genes reported to be involved in tumorigenesis. Thus, RLGS-M can detect alterations in the methylation status of known tumor suppressor genes and provide a method for detecting and subsequently cloning novel genomic regions that undergo alterations in methylation during tumorigenesis.

Animals↗

PubMed1997

Simple and rapid preparation of plasmid template by a filtration method using microtiter filter plates.

We developed a new simple high-throughput plasmid DNA extraction procedure, based on a modified alkaline lysis method, using only one 96-well microtiter glassfilter plate. In this method, cell harvesting, lysis by alkaline and plasmid purification are performed on only one microtiter glassfilter plate. After washing out RNAs or other contaminants, plasmid DNA is eluted by low-ion strength solution, although precipitated chromosomal DNA is not eluted. The plasmid prepared by this method can be applied to sequencing reactions or restriction enzyme cleavage.

Animals↗

PubMed1997

High efficiency selection of full-length cDNA by improved biotinylated cap trapper.

We report here an improved protocol for the preparation of full-length cDNA libraries that improves the previously reported method (Carninci, P., Kvam, K., Kitamura, A. et al. 1996, Genomics, 137, 327-336), that allows long cDNAs to be cloned more efficiently. One potential disadvantage of the original biotinylated CAP trapper protocol is the exposure of mRNA to chemical and enzymatic attacks during the biotinylation of the cap structure, before the first-strand cDNA synthesis (and selection of full-length cDNA by biotinylated cap). Here, we show that the biotinylation of the cap structure is very specific and effective even if biotinylation is performed on the mRNA/cDNA hybrid produced by the first-strand cDNA synthesis reaction. Consequently, mRNA remains protected from chemical and enzymatic degradation during the overnight biotinylation step, thus making it possible to select full-length cDNAs of longer average size. We herein report the efficiency and specificity of the new version of the protocol for cap structure biotinylation and capture of full-length cDNA.

Animals↗

PubMed1997

High-speed positional cloning based on restriction landmark genome scanning.

Restriction landmark genome scanning (RLGS) was developed as a method of genome analysis that is based on the concept that restriction enzyme sites can be used as landmarks. In this article, we demonstrate how this method can be used for the systematic, successful positional cloning of mouse mutant reeler gene. The major advantage of the RLGS method is that it allows the scanning of several thousand spots/loci throughout the genome with one RLGS profile. High-speed positional cloning based on the RLGS method includes (1) high-speed construction of a linkage map (RLGS spot mapping), (2) high-speed detection of RLGS spot markers tightly linked to the mutant phenotype (RLGS spot bombing method), and (3) construction of YAC contigs covering the region where tightly linked spot markers are located (RLGS-based YAC contig mapper). We introduced a series of these procedures by using them to positionally clone the reeler gene. High-speed construction of the whole genetic map and spots/loci (less than 1 cM) within the closest flanking markers is demonstrated. The RLGS-based YAC contig mapper also efficiently yielded the YAC physical contig map of the target region. Finally, we cloned the reeler gene, which is the causal gene for the perturbation of the three-dimensional brain architecture due to the abnormal migration of neuroblasts in reeler mouse. Since the RLGS method itself can be used for any organism, we conclude that the total RLGS-based positional cloning system can be used to identify any mutant gene of any organism.

Animals↗