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Biomedical subjects

Y Yamazaki

Publications and source records attributed to Y Yamazaki.

At least 73 records · Page 4Linked to original sources
PubMed2001

Kinematic approach to gait analysis in patients with rheumatoid arthritis involving the knee joint.

OBJECTIVE: To analyze abnormal gait patterns in patients with rheumatoid arthritis involving the knee joint. METHODS: In 2 patient groups with rheumatoid arthritis, changes in relevant angular parameters in the sagittal plane were analyzed by an electromagnetic tracking instrument. One group consisted of patients with knee joint involvement and severe inflammation without progressive destruction; the other group had knee joint involvement with progressive destruction and low disease activity. Knee angle was measured as the projected angle in the sagittal plane formed by 3 sensors (hip-knee-ankle); the changing mean angle, angular velocity, and angular acceleration were displayed. Furthermore, the angle formed by the vector element's endpoints for each sensor's displacement (designated alpha angle) was measured continuously. RESULTS: Compared with age-matched controls, patients with severe inflammatory knee joint involvement showed limitation of alpha angle change in the stance phase, and patients with knee joint destruction had shortened swing phase duration and decreased alpha angle change in the swing phase. A sharpened alpha angular velocity change curve was observed in the latter. Characteristic differences between groups with inflammation and destruction were more clearly evident from the alpha angle than from the knee angle itself. CONCLUSION: We observed gait differences between rheumatoid arthritis patients with active inflammatory arthritic knee joint involvement without progressive destruction and those with joint destruction and minimal inflammation. Features of gait disturbance in rheumatoid arthritis were not simple, even with a single major site. Therefore, techniques such as biokinetic gait analysis can provide practical information about functional joint integrity in this patient population that could aid in therapeutic decision making.

Adult↗
PubMed2001

Construction of Salmonella typhimurium YG7108 strains, each coexpressing a form of human cytochrome P450 with NADPH-cytochrome P450 reductase.

A series of Salmonella typhimurium (S. typhimurium) YG7108 strains, each coexpressing a form of human cytochrome P450 (CYP) (CYP1A1, CYP1A2, CYP1B1, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, or CYP3A5) together with human NADPH-cytochrome P450 reductase (OR), was established. The parental S. typhimurium YG7108, derived from TA1535, lacks two O(6)-methylguanine-DNA methyltransferase genes, ada and ogt, and is highly sensitive to the mutagenicity of alkylating agents. The expression levels of CYP holo-protein in the genetically engineered S. typhimurium YG7108 cells, determined by carbon monoxide (CO) difference spectra, ranged from 62 nmol/L culture for CYP2C19 to 169 nmol/L culture for CYP3A4. The expression level of the OR varied, depending on the form of CYP coexpressed, and ranged from 214 to 1029 units/L culture. Each form of CYP expressed in the S. typhimurium YG7108 cells catalyzed the oxidation of a representative substrate at an efficient rate. The rates appeared comparable to the reported activities of CYP expressed in human liver microsomes or CYP in other heterologous systems, indicating that the OR was sufficiently expressed to support the catalytic activity of CYP. These S. typhimurium strains may be useful not only for predicting the metabolic activation of promutagens catalyzed by human CYP but also for identifying the CYP form involved.

Alkylating Agents↗
PubMed2001

Hyperbaric oxygenation after portal vein emobilization for regeneration of the predicted remnant liver.

BACKGROUND: Liver failure often develops after extensive liver resection. Preoperative portal vein embolization to induce compensatory hypertrophy in the predicted remnant liver decreases clinical complications after hepatectomy. The aim of this study was to examine whether hyperbaric oxygenation (HBO) after portal vein embolization increases compensatory hypertrophy of the predicted liver remnant. We performed portal vein ligation and HBO in rats to investigate whether HBO after portal vein embolization increases compensatory hypertrophy of the predicted remnant liver. METHODS: Rats were divided into four groups that underwent (1) laparotomy only (control group); (2) right portal vein ligation (RPL group); (3) RPL followed by HBO at 2 atm (HBO-2 atm group; 1 h/day, 5 days/week for 2 weeks); or (4) RPL followed by HBO at 3 atm (HBO-3 atm group). Laparotomy was repeated after 2 weeks in each group; serum levels of albumin and hepatocyte growth factor (HGF) were measured, and the ratio of the weights of nonligated to ligated hepatic segments and the percentage of hepatocytes expressing proliferating cell nuclear antigen (PCNA) in ligated hepatic segments were determined. RESULTS: In rats that had received HBO after RPL, serum levels of HGF, weight ratios of nonligated to ligated hepatic segments, and the percentage of PCNA-positive hepatocytes in nonligated liver were significantly higher than those in the control group. Furthermore, rats that had undergone 3-atm HBO after RPL had significantly higher serum levels of HGF and percentages of PCNA-positive hepatocytes in nonligated hepatic segments. CONCLUSIONS: Preoperative HBO after portal vein embolization may be useful for inducing compensatory hypertrophy of the predicted remnant liver.

Animals↗
PubMed2001

Molecular properties and gene expression of albumin in the skeletal muscle following hindlimb immobilization in a shortened position.

We investigated the effect of immobilization of hindlimb in a shortened position on proteins in the mouse soleus muscle and determined the molecular properties of a protein that had changed specifically in the atrophied muscle. A protein of 67.5 kDa was increased significantly (P<0.001) by 1.9-fold in the atrophied muscle compared to the control muscle as shown by sodium dodecyl sulfate-polyacrylamide (SDS-PAGE). The isoelectric point of the protein was pH 6.3 in two-dimensional PAGE. We carried out N-terminal and peptide mapping analyses to identify the primary structure of the protein. A 17-amino acid sequence showed 100% homology with the mouse serum albumin precursor. A peptide map of the 67.5-kDa protein was similar to that of mouse serum albumin. Mass spectrometry also showed the protein to be most similar to mouse serum albumin. Thus, based on these criteria, the 67.5-kDa protein was indistinguishable from mouse serum albumin. An immunohistochemical study showed that the 67.5-kDa protein was located mainly in the endomysium of the control muscle and had accumulated in the widened interstitial spaces of the atrophied muscle. A reverse transcription-PCR assay revealed that the albumin gene was expressed in skeletal muscle tissue, but that its expression was significantly lower in the atrophied muscle than in the control muscle (P<0.001). We conclude that albumin is increased in atrophied muscle and suggest that this may be of clinical importance for analyzing the process of muscular atrophy.

Albumins↗
PubMed2001

Diverse chalcone synthase superfamily enzymes from the most primitive vascular plant, Psilotum nudum.

Psilotum nudum Griseb is a pteridophyte and belongs to the single family (Psilotaceae) of the division, Psilophyta. Being the only living species of a once populated division, P. nudum is the most primitive vascular plant. Chalcone synthase (CHS; EC 2.3.1.74) superfamily enzymes are responsible for biosyntheses of diverse secondary metabolites, including flavonoids and stilbenes. Using a reverse transcription-polymerase chain reaction strategy, four CHS-superfamily enzymes (PnJ, PnI, PnL and PnP) were cloned from P. nudum, and heterologously expressed in Escherichia coli. These four enzymes of 396-406 amino acids showed sequence identity of > 50% among themselves and to other higher-plant CHS-superfamily enzymes. PnJ and PnP preferred p-coumaroyl-CoA and isovaleryl-CoA respectively, as starter CoA and catalyzed CHS-type ring formation, indicating that they are CHS and phlorisovalerophenone synthase, respectively. On the other hand, PnI and PnL preferred cinnamoyl-CoA as starter CoA and catalyzed stilbene synthase-type cyclization and thus were determined to be pinosylvin synthases (EC 2.3.1.146). In addition, PnE, which uniquely contains a glutamine in place of otherwise strictly conserved histidine, had no apparent in vitro catalytic activity. Phylogenetic analysis indicated that these P. nudum clones form a separate cluster together with Equisetum arvense CHS. This cluster of pteridophytes is located next to the cluster formed by pine (gymnosperm) enzymes, in agreement with their evolutionary relationships. Psilotum nudum represents a plant with the most diverse CHS-superfamily enzymes and this ability to diverge may have provided a survival edge during evolution.

Acyltransferases↗
PubMed2001

Successful surgical treatment of a ruptured abdominal aortic aneurysm without homologous blood transfusion in a Jehovah's Witness: report of a case.

We report herein the case of a 47-year-old woman of the Jehovah's Witness faith in whom Y-grafting for a ruptured abdominal aortic aneurysm was successfully performed without a homologous blood transfusion. We used a Cell Saver (Haemonetics, Braintree, MA. USA) red cell salvaging device and an aortic occlusion balloon catheter, and performed gentle and minimal dissection during the operation. Postoperatively. the patient was kept heavily sedated and required hypothermic therapy for only 14h. We treated her severe anemia using conventional drugs, including iron and folic acid, and her hemoglobin increased smoothly. Although her hemoglobin level decreased to 2.8g/dl during the operation, her postoperative course was uneventful.

Aortic Aneurysm, Abdominal↗
PubMed2001

The wound-healing effect of fibrin glue for tracheal anastomosis in experimental pulmonary surgery.

The leakage of tracheal anastomoses is one of the major complications that occurs after tracheal reconstruction. Improved reinforcing methods for anastomoses would thus be clinically useful. To find a better technique, we examined the postoperative would-healing effect of fibrin glue on tracheal anastomosis in the rat. Experimental rats were divided into two groups. In the control group (n = 21), the trachea was anastomosed by interrupted absorbable sutures. In the fibrin glue group (n = 21), the trachea was anastomosed in the same manner as the control group, with the addition of fibrin glue around the area of anastomosis. In the two groups, we studied the amount of hydroxyproline and histological findings on the seventh, 14th, and 21st postoperative day. The amount of hydroxyproline and collagen fibers in the fibrin glue group was more than in the control group on the seventh postoperative day. These results suggest that fibrin glue has a promotive effect in the healing of tracheal anastomosis.

Anastomosis, Surgical↗
PubMed2001

Study on the Progression of Visual Field Defect and Clinical Factors in Normal-Tension Glaucoma.

Purpose: We investigated the relationship between the progression of visual field defect and clinical factors in patients with normal-tension glaucoma (NTG).Subjects and Methods: Forty-eight eyes of 48 NTG patients undergoing more than 5-year follow-up were enrolled in this study. Their visual field defects ranged between Aulhorn's classification stage 2 and 4, and mean deviation (MD) more than -10 dB measured by Humphrey Field Analyzer (HFA). End points of this follow-up study were defined as follows: in HFA STATPAC 2 glaucoma change probability analysis, more than 5 points which significantly deteriorated at P <.05 were found at 2 consecutive examinations (Criterion 1) or a significant decrease in MD value at P <.025 was encountered at one examination or in MD value at P <.05 at consecutive examinations (Criterion 2).Results: During the follow-up period, 18 eyes of 48 patients satisfied Criterion 1 and 21 eyes Criterion 2. There were no significant differences in clinical factors between patients with progression and without progression. By multiple logistic regression analysis, minimum flow velocity of central retinal artery (CRA) showed significant relation (odds ratio for a 1 cm/sec rise = 0.2215; 95% confidence interval: 0.0530-0.9253) to progression of visual field defect in Criterion 1, and minimum flow velocity of CRA (odds ratio for a 1 cm/sec rise = 0.2099; 95% confidence interval: 0.0506-0.8712) and cholesterol (odds ratio for a 1 cm/dl rise = 1.0332; 95% confidence interval: 0.4096-2.6064) showed significant relation in Criterion 2.Conclusion: These results suggests that vascular risk factors of ocular blood flow may play a role in the progression of visual field defects in NTG patients.

Journal Article↗
PubMed2001

Relationship between outpatients' perceptions of physicians' communication styles and patients' anxiety levels in a Japanese oncology setting.

For life-threatening illnesses such as cancer that require a long-term treatment regimen, communication is particularly important between doctors and patients. While it is assumed that the more serious the illness, the greater the need to relieve patients' anxiety, physicians' communication styles can directly influence patients' anxiety levels. The purpose of this study was to examine the relationship between outpatients' perceptions of physicians' communication styles and the patients' anxiety levels in oncology settings. Patient anxiety level was measured using the State Trait Anxiety Inventory before and after the consultation. The Perceived Physician's Communication Style Scale was developed in this study. Analysis of responses to the scale resulted in four factors--"acceptive", "patient-centered", "attentive", and "facilitative"--of the physician's communication style and explained 63.7% of the variance. The inter-correlation for overall scale items was 0.95. Patient satisfaction with the medical encounter was also measured to validate the physician's communication style scale. Moderate correlation between the physician's communication style and satisfaction was observed and confirms the relationship between a favorable communication style and a patient's satisfaction. After the consultation, the patients' anxiety levels dropped 5.0 +/- 1.5 points (p<0.001), and the physician's communication style was shown in many cases to be linked to patient anxiety levels after the consultation. The effect of the physician's communication style on patients' post-consultation anxiety levels was small among the patients with an advanced disease status. Also, the findings showed that patients' post-consultation anxiety levels remained low even among those patients with unfavorable examination results if the patients evaluated their physician's communication style as high. This study suggested that the physician's communication style is important not only for moderating patients' anxiety, but could also be helpful for moderating physicians' own stress levels when communicating bad news to patients.

Anxiety↗
PubMed2001

Inhibition of myeloid differentiation by Hoxa9, Hoxb8, and Meis homeobox genes.

OBJECTIVE: The homeobox gene Hoxb8 is activated in the murine myelomonocytic cell line WEHI-3B as a result of intracisternal A particle integration. Cooperative activation between Hoxa9 and Meis1 is induced by retroviral integration in BXH2 murine myeloid leukemias and the myeloid leukemia cell line M1. The present study was conducted to examine possible Meis gene activation and cooperative DNA binding of homeobox proteins in WEHI-3B and to reveal the specific role of Hox and Meis genes in myeloid differentiation. MATERIALS AND METHODS: Northern blot analysis and reverse transcriptase polymerase chain reaction were performed to examine homeobox genes expression. Electrophoretic mobility shift assay was performed to evaluate DNA binding of homeobox proteins. Myeloid differentiation of 32Dcl3 was induced by granulocyte colony-stimulating factor. RESULTS: Meis2 was coactivated with Hoxb8 in WEHI-3B cells. DNA-protein complexes including Hox, Meis, and Pbx were observed in WEHI-3B and 32Dcl3. Expression and the DNA-binding complex of Hoxa9, Hoxb8, Meis1, and Meis2 were down-regulated during myeloid differentiation of 32Dcl3 cells. Enforced expression of Hox or Meis genes inhibited myeloid differentiation of 32Dcl3. CONCLUSION: The results indicate that Meis2 is an important Meis gene for myeloid leukemogenesis and that Hox and Meis are important genes for myeloid leukemogenesis through differentiation block.

Animals↗
PubMed2001

Long-term prognosis of patients with West syndrome in Japan: social aspects.

Long-term social prognosis of 120 Japanese patients with West syndrome was surveyed using structured questionnaire at the age of 25.4 years in average. The survey revealed that ADL score remained null in one-fifth of cases; the majority entered in special education course for disabled children; only eleven cases were employed as a full-time worker. As to QOL, 60% of cases were spending daily life with joy. In summary, social prognosis of West syndrome is generally gloomy, but a proportion of patients can lead an independent social life, and an enriched social environment is the most influential factor for better prognosis

Adult↗
PubMed2001

Long-term prognosis of patients with West syndrome in Japan: medical aspects.

In this study, West syndrome prognosis over 20 years was described. All information was obtained from the primary caregivers of patients with West syndrome thorough questionnaires. Of the 259 respondents, 117 patients born between 1960 and 1980 were analyzed. At the age of 20 years two patients were deceased, of the surviving patients, 40% of patients had seizures daily or weekly and 25.2% had been seizure-free for at least 3 years. There was significant difference in the seizure persistence value between West syndrome etiologies but not between the birth cohorts; of those born in the 1960s and 1970s. Compared with severe seizure persistence, which was the duration of the existing daily or weekly seizures at each age, there were no significant difference between birth cohorts and West syndrome etiologies.

Adolescent↗
PubMed2001

The nature and function of mononuclear cells on the resorbed surfaces of bone in the reversal phase during remodeling.

In a reversal phase of bone remodeling many mononuclear cells appear on the resorbed surfaces of bone with characteristic reversal lines as revealed by transmission electron microscopy (TEM). However, these mononuclear cells have been variously hypothesized or reported. The present study examined the TEM features on the resorbed surfaces of three calcified connective tissues, and aimed to clarify the nature and function of the mononuclear cells in a reversal phase. Dentine slices cultured with isolated osteoclasts, human deciduous teeth, and rat mandibles were used in this study. Specimens were fixed, decalcified, and then embedded in Epon 812, and sectioned into 0.1-microm-thick ultrathin sections. The ultrathin sections were stained with uranyl acetate and lead citrate, and then examined by TEM. Many sharply pointed collagen fibrils with striation were observed exposed on the resorbed surfaces of cultured dentine slices, but there were neither cells nor reversal lines. The same features were observed on the root dentine surfaces of human deciduous teeth. Under many mononuclear cells in a reversal phase of remodeling, reversal lines were seen on the resorbed surfaces of rat mandibles, but there were no striated collagen fibrils exposed on the bone surfaces. The alternation of the TEM features on the resorbed surfaces before and after the participation of mononuclear cells in a reversal phase of remodeling suggests the nature and function of these cells: they participate in both degrading the demineralized and disrupted matrix left on the resorbed surfaces and forming reversal lines there.

Animals↗
PubMed2001

Contribution of cumulus cells and serum to the maturation of oocyte cytoplasm as revealed by intracytoplasmic sperm injection (ICSI).

The fertilisability and developmental capacity of mouse oocytes matured in vitro were examined by in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI). While more than 50% of cumulus-enclosed oocytes were fertilised by IVF after maturation in serum-supplemented medium, none were fertilised when the oocytes matured without serum. By ICSI, the majority (78-94%) of the oocytes were fertilised regardless of the presence or absence of serum in oocyte maturation media. Although the majority (88-92%) of cumulus-free germinal vesicle oocytes underwent nuclear maturation in both serum-free and serum-containing media, those matured in the presence of serum were more readily fertilised by ICSI (43%) than those matured without it (3-5%). The cumulus-free oocytes co-cultured with cumulus cells but without serum were fertilised at 36%, suggesting some secreted factor promotes the oocyte's cytoplasmic maturation. The oocytes fertilised by ICSI developed into normal-term fetuses regardless of the presence or absence of serum or cumulus cells in oocyte maturation medium. These results lead us to conclude that (a) the cytoplasm of the oocytes can mature in serum-free medium and (b) the presence of both the serum and the cumulus cells in the medium surrounding maturing oocytes is beneficial for the development of the fertilisation- and development-competence of oocyte cytoplasm.

Animals↗
PubMed2001

Linkage of sugar chains to a fragment peptide of FGF-5S by a chemoenzymatic strategy and changes in the rate of proteolytic hydrolysis.

Various O-linked and N-linked sugar chains were linked enzymatically to a fragment peptide (Leu-Ser-Gln(or Asn)-Val-His-Arg) of FGF-5S. First, galactose was linked with beta-(1-->3)-linkage to GalNAc-linked peptide by a transglycosylation using beta-galactosidase from Bacillus circulans (recombinant). Then sialic acid was linked with the aid of sialyltransferase from rat liver (recombinant) to give NeuAcalpha-(2-->3)-Galbeta-(1-->3)-GalNAc-linked hexapeptide. Further, a sialylated 2-chain biantennary sugar chain was linked by a transglycosylation using endo N-acetyl-beta-D-glucosaminidase from Mucor hiemalis (endo M, recombinant). The activity of DNA synthesis in a fibroblast cell line was increased by this glycosylation. The resistance of the obtained glycopeptides towards proteolytic hydrolysis by rat serum and by five proteases was compared with that of original peptide. The resistance was remarkably enhanced by the glycosylation.

Animals↗
PubMed2001

The effects of a high-carbohydrate diet on the stress-strain behavior of the periodontal ligament of the distal root of the mandibular first molar in hamsters.

We analyzed stress-strain curves in transverse sections at three different root levels of the cervical, middle, and apical regions of the distal root of the mandibular first molar in hamsters fed a high-carbohydrate (experimental group) or standard (control group) diet for 8 weeks. Each section was loaded in vitro at a rate of 5 mm/min in an extrusive direction. The rupture sites and the structures of birefringent collagen fibers in the periodontal ligament were also analyzed. The maximum shear stress, tangent modulus, and failure strain energy density of the periodontal ligament were significantly greater in the cervical region than in the middle and apical regions in both the control and experimental groups. The maximum shear stress, tangent modulus, and failure strain energy density of the periodontal ligament in the experimental group were significantly lower than those in the control group at the cervical and middle regions. The maximum shear strain was significantly greater in the experimental group than in the control group at the middle and apical regions. Histological sections showed that the periodontal ligament ruptured irregularly in both groups. The collagenous fibers of the ligament in the experimental group appeared to be thinner and less birefringent at the cervical and middle regions of the root. These results suggest that a high-carbohydrate diet differentially affects the collagen fibers in the periodontal ligament as a function of the root level, and that these effects are evident in changes in the mechanical properties of the ligament.

Analysis of Variance↗
PubMed2001

Immunohistochemical detection of skin-homing T cells expressing fucosyltransferase VII (Fuc-TVII) in vitro and in situ.

Although expression of cutaneous lymphocyte-associated antigen (CLA) is thought to be a specific marker of skin "homing" T cells, it has become clear that CLA is a good marker for high levels of fucosyltransferase VII (Fuc-TVII) activity but does not necessarily represent the epitope required for binding to E-selectin (Wagers et al, 1996, 1997). Therefore, expression of Fuc-TVII is an attractive candidate for identifying skin "homing" T cells. However, analyses of Fuc-TVII expression in human T cells have been performed only at the mRNA level (Nakayama et al, 2000) because of the lack of mAB: In this study Fuc-TVII was for the first time visualized in individual cells by using a novel mAb that we developed. Double immunofluorescence and immunohistochemistry demonstrated the coexpression of Fuc-TVII and CLA in cell lines in which Fuc-TVII mRNA was shown to be expressed at high levels: whereas CLA expression was seen in the cell membrane, Fuc-TVII was identified in a supra- or perinuclear location. Cytoplasmic Fuc-TVII expression was also detectable in both CD4(+) and CD8(+) T cells purified from peripheral blood. Fuc-TVII was also expressed at high levels in many CLA(+) T cells infiltrating the skin. In these peripheral T cells, unlike in cell lines, cytoplasmic expression of Fuc-TVII was not always associated with surface CLA expression. This mAb would serve as a valuable tool for selectively identifying a novel subset of skin "homing" T cells that are not detected by the conventional method because of the lack of CLA expression.

Antibodies, Monoclonal↗