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Biomedical subjects

Y Iwamoto

Publications and source records attributed to Y Iwamoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

The validity and reproducibility of an oral rating index as a measurement of gingival health care and oral hygiene level in adults.

The purpose of this study was to investigate the validity and reproducibility of an oral rating index (ORI) as a conceptual measurement of "gingival health care" level in adults. The study was conducted on 163 patients who received medical examinations and attended for dental checkups at a hospital. The score of the ORI was recorded as excellent (+2), good (+ 1), questionable (0), poor (-1) or very poor (-2). The validity of the ORI was investigated by comparing it with: Jackson's gingivitis index (GI); Greene & Vermillion's debris index (DI) and calculus index (CI); probing pocket depth (PPD); and percentage of bleeding on probing (%BOP). The intra- and inter-examiner reproducibility of the ORI was assessed on a flat screen using patients' color transparencies of the mouth. The ORI had significantly negative correlations with the GI, DI, CI, and PPD (p<0.001). The K values were 0.604-0.672 for intra-examiner reproducibility, and 0.441-0.449 for inter-examiner reproducibility. The present study suggests that the ORI has moderate to good intra-examiner and inter-examiner reproducibility. Mouth examination using the ORI appears to provide useful information that will enable a dental professional or health educator to make sensible decisions on the type and level of oral health instruction according to adults' gingival health care level.

Adult↗
PubMed2000

Prognostic significance of apoptosis in synovial sarcoma: correlation with clinicopathologic parameters, cell proliferative activity, and expression of apoptosis-related proteins.

bcl-2 overexpression in synovial sarcomas has been recently reported. Although it is widely known that bcl-2 suppresses apoptosis in various cells, there are no studies that have examined the significance of apoptosis in synovial sarcoma. In the present study, we visualized apoptotic tumor cells by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) method in 49 cases of primary synovial sarcoma. The degree of apoptosis was analyzed in relation to several clinicopathologic parameters, cell proliferative activity, and immunohistochemical expression of apoptosis-related proteins, including bcl-2, bax, bcl-x, bak, p53, p21 (WAF1/CIP1), Fas, and Fas ligand. TUNEL index (TUNEL-I) significantly correlated with the mitotic index (MI) (ñ = 0.60, P < .0001) and Ki-67 labeling index (MIB1-I) (ñ = 0.52, P = 0.0005). There was a highly significant association between high TUNEL-I value (>.8%) and poor prognosis (log-rank test; P < .0001). Many synovial sarcomas were diffusely positive for bcl-2 family proteins (bcl-2, bax, bcl-x, and bak) and were negative or only sporadically positive for Fas, Fas ligand, p53, and p21 (WAF1/CIP1) proteins. The results indicated that increased rate of apoptosis in primary synovial sarcoma was considered to be an indicator of poor prognosis. In addition, apoptosis in synovial sarcoma may be controlled by multiple apoptosis-regulating mechanisms, including the bcl-2 family.

Adolescent↗
PubMed2000

Molecular abnormalities of p53, MDM2, and H-ras in synovial sarcoma.

Forty-nine cases of synovial sarcoma were evaluated for mutation of the p53 gene, amplification of the MDM2 gene and mutation of the H-ras gene, and for the relation of these factors to overall survival and clinicopathologic parameters. All investigations were carried out on formalin-fixed paraffin-embedded materials. Furthermore, we evaluated the expression of p53 protein, MDM2, and p21(WAF1/CIP1) immunohistochemically in these cases, together with an assessment of proliferative activities using monoclonal antibody MIB-1. Nine of the 49 cases (18.4%) had p53 gene alteration detected by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing. Eleven cases (24%) showed nuclear accumulation of p53 protein in more than 10% of the tumor cells. Among them, only three cases contained gene mutations. There was no correlation between p53 nuclear accumulation and p53 gene alteration. MDM2 gene amplification, as shown by differential PCR, was observed in 19 out of 47 cases (40%). Nineteen out of 49 cases (38.8%) showed immunoreactivity for MDM2. MDM2 gene amplification and the expression of MDM2 protein showed a significant positive relationship (P = 0.0004). Moreover, MDM2 immunoreaction was significantly correlated with nuclear accumulation of p53 protein (P = 0.023). Positive immunoreaction for p21(WAF1/CIP1) was observed in 21 out of 48 cases (43.8%). p21(WAF1/CIP1) expression was correlated with p53 protein expression. H-ras gene mutations were seen in only three cases (6.1%). All mutations were in codon 12 (one GGC-to-AGC [Gly-to-Ser] mutation and two GGC-to-GAC [Gly-to-Ap] mutations). The gene alteration of p53, MDM2, and H-ras did not affect the patients' prognosis. Although the cases with positive immunoreaction for p53 tended to have a worse prognosis, the difference was not statistically significant (P = 0.13). No correlation was observed between MIB-1 LI and the immunohistochemical expression of p53, MDM2, and p21(WAF1/CIP1) or the mutation status of p53 and H-ras. On the other hand, high MIB-1 LI (more than 10) significantly correlated with poor prognosis (P < 0.0001). Our results suggest that p53 gene mutation does not appear to be a major prognostic factor and H-ras mutations are infrequent in synovial sarcoma.

Adolescent↗
PubMed2000

Higher incidence of diabetic nephropathy in type 2 than in type 1 diabetes in early-onset diabetes in Japan.

BACKGROUND: Whether the type of diabetes, race, and year and age of diagnosis affect the incidence of diabetic vascular complications is unknown. That both type 1 and type 2 diabetes occur in the young Japanese population prompted us to investigate whether the type of diabetes and the year of diagnosis are related to the incidence of nephropathy. METHODS: Of the 17,256 diabetic patients who visited the outpatient clinic at our diabetes center between 1965 and 1990, 1578 (9.1%) had early-onset diabetes (diagnosed before the age of 30); of these, 620 (39%) had type 1, and 958 (61%) had type 2 diabetes. The incidence of nephropathy was analyzed in the patients according to postpubertal duration and year of diagnosis. RESULTS: The cumulative incidence of nephropathy after 30 years of postpubertal diabetes was significantly higher (P < 0.0001) in type 2 diabetic patients (44.4%, 95% CI, 37.0 to 51.8%) than in type 1 diabetic patients (20.2%, 95% CI, 14.9 to 25.8%). The incidence of nephropathy among type 1 diabetic patients has declined during the past two decades, whereas it has not among type 2 diabetic patients. The rate ratio for type 2 diabetic patients diagnosed between 1980 and 1984 relative to type 1 diabetic patients diagnosed in the same period was 2.74 (95% CI, 1. 17 to 6.41). CONCLUSIONS: The incidence of nephropathy has declined in Japanese patients with type 1 but not in those with type 2 diabetes. In young Japanese patients, because of the higher incidence of nephropathy in type 2 diabetes and the higher prevalence of type 2 than type 1 diabetes, type 2 diabetes is likely the major cause of diabetic nephropathy.

Adolescent↗
PubMed2000

Comparison of histological changes and changes in nm23 and c-MET expression between primary and metastatic sites in osteosarcoma: a clinicopathologic and immunohistochemical study.

Changes in morphological features between the primary and metastatic sites in osteosarcoma and the role of nm23 protein and c-MET oncogene product have remained controversial. In addition to histological studies, we evaluated the expression of nm23, c-MET, p53, and MDM2 immunohistochemically using 25 osteosarcomas in which both primary and concordant metastatic specimens were available. Moreover, we assessed proliferative activity using the monoclonal antibody MIB-1. Among these 25 cases, 4 tumors that were osteoblastic type (16%) in the primary site had changed morphologically to MFH-like type in the metastatic site, whereas 2 MFH-like type and 1 small cell-type tumors had changed to osteoblastic type. MIB-1 LI was significantly higher in the metastatic site than in the primary site (primary, 20.02; metastatic, 26.72; P = .0209). Seventeen cases (68%) showed increased nm23 expression in the metastatic site, whereas 2 cases showed reduced expression. nm23 expression was significantly increased in the metastatic site, compared with the primary site (P = .0009). Seven cases (28%) showing negative reaction for c-MET in the primary site showed immunuoreactivity for c-MET in the metastatic site. Although there was no statistical significance, c-MET expression seemed to be more frequent in the metastatic site, compared with the primary site. Among the overall tumors, c-MET-positive tumors showed significantly higher MIB-1 LI, compared with c-MET-negative tumors (negative, 20.99; positive, 27.65; P = .0292). No significant change was observed regarding p53 and MDM2 between the primary and metastatic site. Our results suggest that rather than being a metastasis-suppressor gene, nm23 is in fact correlated with metastatic progression in osteosarcoma. Positive correlation between c-MET expression and proliferative activity also suggests that c-MET expression may play an important role in tumor progression in osteosarcomas.

Adolescent↗
PubMed2000

Disassembly of a Howmedica modular resection system.

We report the postoperative disassociation of a Morse taper junction of a Howmedica Modular Resection system implanted after the resection of a malignant distal femoral bone tumor. The disassembly occurred without apparent trauma. This complication was managed by closed reduction under epidural anesthesia. This disassembly probably occurred because of decreased tension of the soft tissue around the prosthesis or an impaired locking mechanism.

Adult↗
PubMed2000

The mechanical properties of locking and grasping suture loop configurations in four-strand core suture techniques.

We have compared the effect of locking and grasping suture loop configurations in four-strand core suture techniques for tendon repair. Forty canine flexor digitorum profundus tendons were repaired with one of four suture techniques (the grasping cruciate, the double-modified grasping Kessler, the locking cruciate and the double-modified locking Kessler) and tested to failure in a tensile testing machine. The mode of failure in all the locking suture specimens was breakage of the sutures in the locking loops or at suture knots. The sutures did not pull out of the tendon, as was seen in the grasping suture specimens. The greatest tensile strength was found with the double-modified locking Kessler technique which incorporated eight rectangular locking loop configurations.

Animals↗
PubMed2000

Tibial tubercle malposition in patellar joint instability: a computed tomograpy study in full extension and at 30 degree flexion.

We evaluated the tibial tubercle position in knees with patellar instability. CT in full extension and at 30 degree flexion was used in 18 knees with instability and 18 control knees. Scans were taken at the level of the femoral epicondyles, tibial tubercle and distal tibia. We found that in full extension, the tibial tubercle was in a more lateral position in the unstable than in the control knees. At 30 degree flexion, the tibial tubercle in the unstable knees rotated internally, but it was never within the normal range. CT scans taken in full extension and at 30 degree flexion seem to be of value for ascertaining the degree of tibial tubercle malposition during knee flexion in patellar instability.

Adolescent↗
PubMed2000

Unusual cytotoxic activities of thymus-independent, self-antigen-specific CD8(+) T cells.

We compared the cytotoxic activities of thymus-dependent and thymus-independent CD8(+) T cells. Thymus-dependent CD8(+) T cells, which are foreign antigen specific, acquired cytotoxic activity to tumor cells with a basal dose of the antigen peptides and to hybridoma cells expressing anti-TCR mAb only after differentiation into effector cytotoxic T lymphocytes (CTL). In contrast, thymus-independent CD8(+) T cells, which have been shown to be self-antigen specific, never showed cytotoxic activity to the target cells with a basal dose of the self-antigen peptide, while they could lyse hybridoma cells expressing anti-TCR mAb even without prior antigenic stimulation. Furthermore, the ex vivo cytotoxic activity of thymus-independent CD8(+) T cells was also observed against the target cells with high doses of the antigen peptides, which were not lysed by freshly isolated thymus-dependent CD8(+) T cells. Thus it is revealed that thymus-independent, self-antigen-specific CD8(+) T cells already acquire mature CTL functions in situ but have an increased threshold of TCR-mediated signaling for activation. These differences in cytotoxic activities between thymus-dependent and thymus-independent CD8(+) T cells suggest distinct roles of the two subsets of CD8(+) T cells in vivo.

Animals↗
PubMed2000

Treatment of myxoid liposarcoma in pregnancy.

Two cases of pregnancy associated with myxoid liposarcoma are presented. Both patients were treated with hyperthermoradiotherapy after the induced delivery of healthy infants and by surgical excision of the tumor 5 to 7 weeks after delivery. No local recurrence or distant metastasis occurred; the children have progressed normally for 4 and 5 years, respectively, after surgery. Because coexistence of pregnancy and sarcoma is rare, it is difficult for the clinician to develop an appropriate approach to the management of bone and soft tissue sarcoma during pregnancy. The literature was reviewed regarding the effect that pregnancy may have on the clinical behavior of sarcoma and the effect treatment for sarcoma may have on the fetus.

Adult↗
PubMed2000

Clinical features of multiple epiphyseal dysplasia expressed in the knee.

The purpose of this study is to clarify the clinical features of the knee affected by multiple epiphyseal dysplasia. Thirty-one cases of multiple epiphyseal dysplasia were reviewed. Of the patients, 11 were male and 20 were female. The average age at onset of symptoms was 22.5 years. The average age at initial visit to the authors' hospital was 28.9 years. Radiographic findings showed epiphyseal abnormality of the knee in all but two (93%) cases. Irregularity, segmentation of the epiphysis, widening of the joint space, and genu valgum deformity were the dominant findings before epiphyseal closure. After epiphyseal closure, the most characteristic finding was a shallow femoral trochlear groove, which was observed in 56.5% of the cases. Other findings in adult patients included early onset osteoarthritic change, genu valgum, depression of the lateral tibial plateau, and multiple free bodies. However, there still is a possibility that multiple epiphyseal dysplasia exists, even if the patient lacks a shallow femoral trochlear groove. If genu valgum or varum, free bodies, and premature osteoarthritis are observed, one should evaluate other joints, keeping a diagnosis of multiple epiphyseal dysplasia in mind. Patients with knees that have a femoral trochlear groove of normal or near normal shape do exist, and premature osteoarthritic changes may develop in such patients.

Adolescent↗
PubMed2000

False localization of rupture site in patients with multiple cerebral aneurysms and subarachnoid hemorrhage.

OBJECTIVE: Patients with subarachnoid hemorrhage and multiple intracranial aneurysms present a unique challenge to the neurosurgeon. Unless all aneurysms can be clipped through a single craniotomy, the surgeon must accurately determine which aneurysm has ruptured. Misjudgment may result in disastrous postoperative rebleeding from the untreated but true ruptured lesion. We assessed the risk of false localization of the rupture site and subsequent rebleeding and documented the problems in predicting the true rupture site when patients have multiple intracranial aneurysms. METHOD: We reviewed the records of a consecutive series of 93 patients treated over a period of 12 years who presented with their first subarachnoid hemorrhage and who had multiple intracranial aneurysms. The rupture site was determined on the basis of computed tomographic and angiographic findings, and the supposed ruptured aneurysm was clipped within 2 days of hemorrhage in each patient. Additional aneurysms that could not be accessed in the same surgical session were operated on at a later stage. All patients' records were reviewed, and all computed tomographic scans and angiograms, including repeat studies performed in some patients, were retrospectively reevaluated by the authors, who had no knowledge of the patients' clinical information. RESULTS: The location of the aneurysm that ruptured was verified at the time of surgery or during the autopsy in 76 patients (82%). The aneurysm that ruptured was the one predicted as ruptured by the surgeon before surgery in 69 patients (91%) and in retrospect in 72 patients (95%). Five of the 6 patients in whom the ruptured aneurysm was not correctly identified were thought to have only a single aneurysm. Four patients rebled after surgery, and 2 patients died as a result of the rebleeding. CONCLUSION: In the reported series, the most common cause of rebleeding soon after aneurysm surgery was failure to obliterate the ruptured aneurysm, usually because it was missed on the initial angiogram. The results support not only meticulous radiological investigation of all intracranial arteries before surgery but also thorough surgical inspection of the target aneurysm in all cases of subarachnoid hemorrhage even after one candidate lesion has been discovered.

Adult↗
PubMed2000

A zinc finger transcription factor, alphaA-crystallin binding protein 1, is a negative regulator of the chondrocyte-specific enhancer of the alpha1(II) collagen gene.

Transcription of the type II collagen gene (Col2a1) is regulated by multiple cis-acting sites. The enhancer element, which is located in the first intron, is necessary for high-level and cartilage-specific expression of Col2a1. A mouse limb bud cDNA expression library was screened by the Saccharomyces cerevisiae one-hybrid screening method to identify protein factors bound to the enhancer. A zinc finger protein, alphaA-crystallin binding protein 1 (CRYBP1), which had been reported to bind to the mouse alphaA-crystallin gene promoter, was isolated. We herein demonstrate that CRYBP1 is involved in the negative regulation of Col2a1 enhancer activity. CRYBP1 mRNA expression was downregulated during chondrocyte differentiation in vitro. In situ hybridization analysis of developing mouse cartilage showed that CRYBP1 mRNA was also downregulated during mesenchymal condensation and that CRYBP1 mRNA was highly expressed by hypertrophic chondrocytes, but at very low levels by resting and proliferating chondrocytes. Expression of recombinant CRYBP1 in a transfected rat chondrosarcoma cell line inhibited Col2a1 enhancer activity. Electrophoretic mobility shift assays showed that CRYBP1 bound a specific sequence within the Col2a1 enhancer and inhibited the binding of Sox9, an activator for Col2a1, to the enhancer. Cotransfection of CRYBP1 with Sox9 into BALB/c 3T3 cells inhibited activation of the Col2a1 enhancer by Sox9. These results suggest a novel mechanism that negatively regulates cartilage-specific expression of Col2a1.

Animals↗
PubMed2000

Prediction of the outcome of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head.

We have studied the correlation between the prevention of progressive collapse and the ratio of the intact articular surface of the femoral head, after transtrochanteric rotational osteotomy for osteonecrosis. We used probit analysis on 125 hips in order to assess the ratio necessary to prevent progressive radiological collapse over a ten-year period. The results show that a minimum postoperative intact ratio of 34% was required. This critical ratio may be useful for surgical planning and in assessing the natural history of the condition.

Adult↗
PubMed2000

Effect of vitamin K2 on three-dimensional trabecular microarchitecture in ovariectomized rats.

Menatetrenone, a vitamin K2 with four isoprene units, has been reported to improve osteoporotic bone loss. The purpose of this investigation was to clarify the effect of menatetrenone on the three-dimensional (3D) trabecular microarchitecture in ovariectomized (OVX) rats by using microcomputed tomography (MCT). Forty-two 13-week-old female rats were used and divided into four groups: the OVX (OVX + MK-4) group treated with menatetrenone, the (OVX untreated) group, the sham-operated (Sham + MK-4) group treated with menatetrenone, and the sham-operated group not treated with menatetrenone (Sham untreated) group. OVX rats were fed a calcium-deficient diet. Menatetrenone treatment was begun just after the ovariectomy, and the mean menatetrenone oral intake over the 8-week period was adjusted to 30 mg/kg BW per day. The proximal metaphyseal region of the right tibia was evaluated by dual X-ray absorptiometry (DXA) and MCT. A parametric analysis of the reconstructed trabecular volume was carried out using bone volume fractions, the fractal dimension calculated by the 3D box-counting method, and the connectivity density as determined by topological analysis. Menatetrenone significantly increased the trabecular bone volume, fractal dimension, and connectivity in the OVX + MK-4 group compared with the OVX-untreated group (p < 0.01). Our results suggest that an 8-week administration of menatetrenone protects against the loss of trabecular bone volume and its connectivity when treatment is begun just after the ovariectomy. Despite this apparent protection, it remains unknown whether it is possible to reestablish trabecular connectivity if therapeutic intervention occurs after the trabecular connectivity has been lost.

Alkaline Phosphatase↗
PubMed2000

Characterization of an early decline in baseline plasma glucose concentration after acute insulin elevation during euglycemic hyperinsulinemic clamp in patients with type 2 diabetes mellitus.

To investigate the contribution of the liver to whole-body insulin resistance in patients with type 2 diabetes mellitus, we analyzed the early decline (slope "a") in the baseline plasma glucose level following acute hyperinsulinemia in the initial phase of a euglycemic hyperinsulinemic clamp study, rather than using an isotope-dilution method. Slope "a" was comparable among groups of diabetic and non-diabetic subjects, and did not correlate well with glucose infusion rate (GIR), an index of peripheral (primarily skeletal muscle) insulin resistance. In contrast, slope "a" was significantly lower in obese (BMI > 25) type 2 diabetic patients compared with their non-obese counterparts, consistent with the general belief that obesity is a condition of insulin resistance in liver as well as in peripheral tissues. A subset of six insulin-resistant (nearly zero GIR) type 2 diabetic patients (pubertal adolescents) demonstrated a markedly blunted slope "a". Their insulin resistance (GIR) substantially recovered concomitant with an increase in slope "a" after pretreatment with somatostatin analogue in two cases studied, suggesting possible suppression of hepatic glucose production through lowering of plasma glucagon concentrations. Furthermore, slope "a" correlated significantly (r = -0.480, p<0.0001) with HOMA index (FPG x FIRI), the latter being recently regarded as an index of hepatic insulin resistance. These data showed that slope "a" obtained from euglycemic hyperinsulinemic clamp may be a clinically useful index of hepatic insulin resistance rather than an index of peripheral insulin resistance.

Adolescent↗
PubMed2000

Polymyalgia rheumatica and type 2 diabetes mellitus complicated with electromyographic abnormalities that responded well to corticosteroid therapy.

A 62-year-old man who had a 14-year history of diabetes complained of low-grade fever, general malaise, pain of bilateral femurs and hip girdle, and was adniitted to our hospital. The diagnosis of polymyalgia rheumatica (PMR) was made from the clinical symptoms, elevated C-reactive protein and erythrocyte sedimentation rate. Electromyography revealed abnormalities that suggested diabetic peripheral neuropathy. However, the abnormalities were improved after starting treatment with corticosteroids (PSL). After stopping PSL, electric nerve conduction disturbance developed; therefore, it was suggested that peripheral nerve involvement due to PMR was improved by administration of PSL regardless of the existence of diabetic peripheral neuropathy.

Autoimmune Diseases↗