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Biomedical subjects

Y Okada

Publications and source records attributed to Y Okada.

At least 505 records · Page 28Linked to original sources
PubMed1998

A newly developed shunt system for carotid surgery: T-shaped silicone shunt tubes and clamping devices: technical note.

BACKGROUND: Although the use of a shunt during carotid endarterectomy has been controversial, a convenient shunt system is still required. METHODS: We have devised an intraluminal shunt system, T-shaped silicone shunt tubes, and clamping devices for carotid surgery. The tube has enough pliability and length to be used in a looped or U-shaped mode and constructs a T-shape with a side arm available for monitoring blood pressure in the shunt system. Clamping devices, such as modified Sugita ring clips and encircle type bulldog clamps, make it possible to hold the tube by a simple maneuver and to minimize the intimal damage. RESULTS: This shunt system has been used in 170 carotid endarterectomies and other 10 carotid surgical operations, and the mortality and morbidity rates were 0% and 2.4%, respectively. CONCLUSION: This shunt system can be safely and easily used for cervical carotid surgery.

Brain Ischemia↗
PubMed1998

Serotype variation in Streptococcus anginosus, S. constellatus and S. intermedius.

Various serotypes reported in three serotyping systems for the 'Streptococcus milleri' group, i.e., Ottens I-IV, Osano I-IV and serotypes a-k, were compared with each other in a capillary precipitation test and by the double immunodiffusion test. Only two of the 19 serotypes, f and Ottens-III, were identical, and the other 17 serotypes were independent. Thus, 18 serotypes and another three candidates (a-, b- and g-cross-reactive) were found in the 'S. milleri' group. Of the 248 strains tested, 197 were serotypable, and 23 strains carried two type antigens. Generally, the Ottens I, II, III (serotype f), IV and Osano IV antigens, often together with the Lancefield group F antigen, were found in S. anginosus and S. constellatus. In addition, the serotype a, c, d, e and k antigens with the group A, C or G antigen were distributed in S. anginosus, the serotype b antigen in S. constellatus and the g, h, i, j, Osano I, II and III antigens in S. intermedius. Twenty-five of the untypable strains were Lancefield groupable (mostly F).

Animals↗
PubMed1998

Expression of uroplakin Ib and uroplakin III genes in tissues and peripheral blood of patients with transitional cell carcinoma.

Uroplakins (UPs), urothelium-specific transmembrane proteins, are present only in urothelial cells. We have determined the nucleotide sequences of human UP-Ib and UP-III and synthesized specific primer pairs. The two UP genes were expressed in both cancerous and noncancerous urothelial taken from all patients examined by reverse transcription-polymerase chain reaction (RT-PCR). These genes were also detected in the peripheral blood of 3 patients with metastatic transitional cell carcinoma (TCC), but not in that from 9 patients with non-metastatic TCC or 3 healthy volunteers. The sensitivity of our assay was sufficient to detect one cancer cell in 5 ml of peripheral blood. Detection of UP gene-expression in blood by RT-PCR may provide helpful information for the diagnosis and management of TCC.

Adult↗
PubMed1998

Decision analysis for treatment of early stage prostate cancer.

We performed a decision analysis to evaluate the usefulness of pretreatment prediction of clinically significant or insignificant tumor in patients with prostate-specific antigen (PSA)-detected stage T1c prostate cancer nonpalpable on rectal examination. Analysis was done for otherwise healthy subjects with 20 years of life expectancy. The prevalence of insignificant tumor among those with T1c prostate cancer was initially assumed to be 0.2. Quality-adjusted life expectancy was calculated and compared between 2 strategies; one with prediction-based selection of either radical prostatectomy or watchful waiting and the other with unselective assignment of one of the treatments. The selection strategy was superior when the sensitivity and specificity for detecting clinically significant tumor were 0.92 and 0.73, respectively, as reported by Epstein et al. (1994) using criteria of PSA density and Gleason score in a needle biopsy specimen. Sensitivity analysis revealed that the prediction-based selection strategy is preferred, with sensitivity and specificity constant, when the prevalence of insignificant tumor exceeds 0.16. On the other hand, when the prevalence of insignificant tumor is kept constant at 0.2, sensitivity should be 0.85 or higher for the prediction strategy to be preferred. As the prevalence of insignificant tumor among those with T1c prostate cancer increased, the prediction-based selection strategy is preferred with lower values of sensitivity and specificity for detecting significant tumor. These results suggest that a selective treatment strategy of either radical or conservative treatment based on pretreatment prediction for significant tumor is a beneficial alternative to radical prostatectomy unselectively assigned to all patients at the T1c stage, if a reasonable accuracy in prediction is attained.

Decision Support Techniques↗
PubMed1998

Growth inhibition of CD20-positive B lymphoma cell lines by IDEC-C2B8 anti-CD20 monoclonal antibody.

Treatment with IDEC-C2B8 (C2B8), the chimeric anti-CD20 antibody, was shown in a phase I-II study to be very effective for the treatment of low-grade B-cell lymphoma, in contrast to the results of most previous immunotherapies with monoclonal antibodies. In a study designed to elucidate the reason for this efficacy, two cell lines derived from lymphomas with BCL2 gene rearrangement (SU-DHL-4 and SU-DHL-6) showed remarkable growth inhibition and cell-death, and two other cell lines derived from a diffuse lymphoma (RC-K8) and a mantle cell lymphoma (SP-49) showed moderate growth inhibition, but neither a CD20 weakly positive cell line (NALL-1) nor a negative cell line (MOLT-4) showed any growth inhibition. An examination of the intensity of cell-surface CD20 expression showed no correlation between intensity and degree of growth inhibition among the four cell lines showing growth inhibition. Morphological examination revealed condensed and fragmented nuclei and budding of the plasma membrane, both characteristic of apoptosis, with some cells in these cell lines showing growth inhibition by C2B8. Such apoptosis was also confirmed by flow cytometric analysis, suggesting that, at least in part, apoptosis plays a role in this growth inhibition. This growth-inhibitory mechanism may thus account for the effectiveness of C2B8 antibody therapy.

Animals↗
PubMed1998

Case report: Insulin-like growth factor II expression in hepatocellular carcinoma with alcoholic liver fibrosis accompanied by hypoglycaemia.

This case of hepatocellular carcinoma (HCC) with alcoholic liver fibrosis, which was not associated with hepatitis viruses, was accompanied by hypoglycaemia. The immunoreactive insulin level was low and other hormonal examinations were almost normal. Immunohistochemical studies showed a high level of insulin-like growth factor II (IGF2) peptide in the HCC section and the size heterogeneity of serum IGF2 investigated by western blot revealed a large form at approximately 15 kDa. These results suggest that the HCC with alcoholic liver fibrosis produced IGF2 and that the hypoglycaemia was caused by tumour-associated IGF2.

Carcinoma, Hepatocellular↗
PubMed1998

Transurethral electrovaporization of the prostate: preliminary clinical results with pressure-flow analysis.

BACKGROUND: We evaluated the safety and efficacy of transurethral electrovaporization of the prostate (TVP) as a new alternative treatment for patients with benign prostatic hyperplasia. METHODS: A total of 22 patients with symptomatic benign prostatic hyperplasia, including 4 with urinary retention, underwent TVP. If enough of a cavity was not created after 60 minutes of vaporization, transurethral resection of the prostate (TURP) was performed successively. International Prostate Symptom Score (I-PSS) with quality-of-life index, maximum flow rate, and postvoid residual volume were measured at baseline and at 2 weeks, 1, 3, and 6 months. A pressure-flow study was performed at baseline and at 3 or 6 months after surgery. RESULTS: TURP was required in 10 of 22 patients. At 6 months, mean I-PSS decreased from 20.0 to 5.2, quality-of-life index decreased from 4.6 to 1.1, mean maximum flow rate increased from 6.9 to 16.7 mL/s, and postvoid residual volume decreased from 152 to 32 mL. Detrusor pressure at maximum flow decreased from 108 to 39 cm H2O, with a significant relief of bladder outlet obstruction in 93% of the patients. Mean decrease in hematocrit was 4.4%, and in serum sodium, 4.8 mEq/L. None of the patients required transfusions or had TUR syndrome. A urethral stricture and a severe stress incontinence developed in 1 patient. CONCLUSION: TVP seems to be a safe and effective alternative to a standard TURP associated with fewer intraoperative complications. Although preliminary clinical results have been promising, further study is necessary to establish long-term efficacy and safety of this procedure.

Aged↗
PubMed1998

Surveillance study for clinical stage I testicular seminomas and nonseminomatous germ cell tumors.

BACKGROUND: Optimal therapy for stage I testicular tumors is still controversial. This study evaluated the efficacy of a surveillance policy for patients with testicular stage I seminomas and nonseminomatous germ cell tumors (NSGCT). METHODS: From 1984 to 1996, 24 patients with stage I seminoma and 20 with stage INSGCT were followed after radical orchiectomy with tumor markers and imaging studies. All patients were followed for at least 2 years except for those who recurred within 2 years. Recurrent patients were treated with cisplatin-based chemotherapy. RESULTS: The median follow-up periods for seminoma and NSGCT patients were 41 and 54 months, respectively. Recurrences were detected in 2 seminoma (8.3%) and 10 NSGCT (50%) patients. Eleven of the 12 recurrent patients (92%) were detected within 2 years after orchiectomy. The seminoma patients both recurred in the retroperitoneal lymph nodes, while 70% of the NSGCT patients recurred in the lung and/or retroperitoneal lymph nodes. The recurrent seminoma patients were treated with chemotherapy and are alive without disease for 1 7 and 24 months afterorchiectomy. One NSGCT patient died of cancer, but the other 9 recurrent NSGCT patients are alive without disease at 25 to 113 months after orchiectomy. CONCLUSIONS: Surveillance alone is reliable for monitoring patients with stage I testicular seminoma and NSGCT. The majority of recurrences occurred within 2 years, necessitating intensive follow-up for 3 years. As the lung metastatic rates in NSGCT patients were high, a more accurate assessment for lung metastasis is desirable in these patients.

Adolescent↗
PubMed1998

Mandibular stability after sagittal split ramus osteotomy without post-operative maxillomandibular fixation in the treatment of prognathic patients with symmetric mandibles.

This study was designed to examine post-operative stability in prognathic patients with symmetric lower jaws who underwent sagittal split ramus osteotomy (SSRO) of the mandible without post-operative maxillomandibular fixation (MMF). Twenty prognathic patients with symmetric mandibles were investigated. An appliance for repositioning the proximal segment and titanium screw fixation was applied in all patients. Ten patients underwent post-operative MMF with stainless steel wire (mean duration, 9.6 days) and intermaxillary rubber traction after removal of the MMF (Group I), and the remaining ten underwent intermaxillary rubber traction only (Group II) post-operatively. Cephalograms were obtained 2-3 days post-operatively, and 3, 6, and 12 months after surgery. Changes in the positions of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. In the early stages of follow-up, decreases in the overbite tended to be more marked in Group I than in Group II, and the forward movement of each standard point was significantly larger in Group I than in Group II. No significant differences, however, were revealed between the two groups at 12 months after surgery. Forward movement of anterior cephalometric landmarks, post-operatively, in Group II were significant, however, this pattern differed from Group I, in which big changes occurred in the early stages after surgery. Although the patterns of post-operative changes in the two groups are different, there are no significant differences in their post-operative stability in long-term follow-up. Therefore, post-operative MMF may be avoided when prognathic patients with symmetric mandibles undergo SSRO with an appliance for repositioning the proximal segment and titanium screw fixation.

Adult↗
PubMed1998

Heterosexual transmission of a murine AIDS virus.

Heterosexual transmission of a murine leukemia virus mixture named LP-BM5 MuLV, which is known as the murine AIDS virus, was investigated. Our results indicated that the heterosexual transmission of LP-BM5 MuLV occurs in both directions with high frequency and that the frequencies of virus transmission in the cervix and penis are higher than those in other genital organs. The results suggested that infection by LP-BM5 MuLV via heterosexual transmission may initially take place at particular retrovirus-sensitive sites (cells) in the genital organs.

Animals↗
PubMed1998

Binding of murine leukemia virus Gag polyproteins to KIF4, a microtubule-based motor protein.

A cDNA clone encoding a cellular protein that interacts with murine leukemia virus (MuLV) Gag proteins was isolated from a T-cell lymphoma library. The sequence of the clone is identical to the C terminus of a cellular protein, KIF4, a microtubule-associated motor protein that belongs to the kinesin superfamily. KIF4-MuLV Gag associations have been detected in vitro and in vivo in mammalian cells. We suggest that KIF4 could be involved in Gag polyprotein translocation from the cytoplasm to the cell membrane.

Animals↗
PubMed1998

Inflammatory bowel disease-like enteritis and caecitis in a senescence accelerated mouse P1/Yit strain.

BACKGROUND: A new subline of the senescence accelerated mouse (SAM) P1/Yit strain has been established which shows spontaneous enteric inflammation under specific pathogen free (SPF) conditions. AIMS: To elucidate the pathogenesis of enteric inflammation in this new subline. METHODS: The SPF and germ free (GF) SAMP1/Yit strains were used. Histological, immunological, and microbiological characterisation of the mice with enteric inflammation was performed. RESULTS: Histologically, enteritic inflammation developed as a discontinuous lesion in the terminal ileum and caecum with the infiltration of many inflammatory cells after 10 weeks of age. the activity of myeloperoxidase, and both immunolocalisation and mRNA expression of inducible nitric oxide synthase increased in the lesion. CD3-epsilon positive T cells, neutrophils, and macrophages were more numerous in the inflamed mucosa of the SAMP1/Yit strain. The GF SAMP1/Yit strain did not show any inflammation in the intestinal wall, by the age of 30 weeks, and the enteritis and caecitis developed 10 weeks after the conventionalisation of the GF SAMP1/Yit strain. CONCLUSION: Enteric inflammation in the ileum and caecum developed in the SAMP1/Yit strain. The pathophysiological characteristics of the disease in this mouse have some similarities to those of human inflammatory bowel disease (IBD). This mouse strain should be a useful model system for elucidating the interaction between the pathogenesis of IBD and the gut microflora.

Aging↗
PubMed1998

Glibenclamide blocks volume-sensitive Cl- channels by dual mechanisms.

To study the mechanisms of glibenclamide actions on volume-sensitive Cl- channels, whole cell patch-clamp studies were performed at various pH levels in human epithelial Intestine 407 cells. Extracellular application of glibenclamide reversibly suppressed volume-sensitive Cl- currents in the entire range of voltage examined (-100 to +100 mV) and accelerated the depolarization-induced inactivation at pH 7.5. When glibenclamide was applied from the intracellular side, in contrast, no effect was observed. At acidic pH, at which the weak acid glibenclamide exists largely in the uncharged form, the instantaneous current was, in a voltage-independent manner, suppressed by the extracellular drug at micromolar concentrations without significantly affecting the depolarization-induced inactivation. At alkaline pH, at which almost all of the drug is in the charged form, glibenclamide speeded the inactivation time course and induced a leftward shift of the steady-state inactivation curve at much higher concentrations. Thus it is concluded that glibenclamide exerts inhibiting actions on swelling-activated Cl- channels from the extracellular side and that the uncharged form is mainly responsible for voltage-independent inhibition of instantaneous currents, whereas the anionic form facilitates voltage-dependent channel inactivation in human epithelial Intestine 407 cells.

Cell Line↗
PubMed1998

Sour transduction involves activation of NPPB-sensitive conductance in mouse taste cells.

We examined the sour taste transduction mechanism in the mouse by applying whole cell patch-clamp technique to nondissociated taste cells from the fungiform papillae. Localized stimulation with 0.5 M NaCl and 25 mM citric acid (pH 3.0) of the apical membrane enabled us to obtain responses from single taste cells under a quasi-natural condition. Of 28 taste cells examined, 11 cells (39%) responded to 0. 5 M NaCl alone and 2 cells (7%) responded to 25 mM citric acid alone, indicating the presence of salty- and sour-specific taste cells. Ten cells (36%) responded to both NaCl and citric acid and 5 cells (18%) responded to neither salt nor citric acid. Amiloride reversibly suppressed NaCl-induced responses in mouse taste cells but not citric acid-induced responses. On the other hand, a Cl- channel blocker, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), reversibly suppressed all the citric-acid-induced responses. Most of the NaCl-induced current responses displayed an inwardly rectifying property, whereas all the citric-acid-induced responses displayed an outwardly rectifying property. The reversal potential for NPPB-sensitive component in citric-acid-induced current responses was -2 +/- 7 mV (mean +/- SE, n = 4), which was close to the equilibrium potential of Cl- (ECl), whereas the reversal potential for NPPB-insensitive component was 34 +/- 8 mV (n = 4). The reversal potential of citric-acid-induced current responses (19 +/- 8 mV, n = 4) was mostly present at the middle point between reversal potentials of NPPB-sensitive and -insensitive current components. In some taste cells, an inorganic cation channel blocker, Cd2+, suppressed citric-acid-induced responses, but an inorganic stretch-activated cation channel blocker, Gd3+, did not affect these responses. These results suggest that salt- and acid-induced responses were mediated by differential transduction mechanisms in mouse taste cells and that NPPB-sensitive Cl- channels play a more important role to sour taste transduction rather than amiloride-sensitive Na+ channels. However, the fact that the reversal potentials of citric-acid-induced responses had more positive than ECl suggests that Ca2+ or H+ permeable and poorly selective cation channels, which should be amiloride insensitive, may be activated by citric acid.

Amiloride↗
PubMed1998

Studies on the role of adhesive proteins in maintaining pregnancy.

UNLABELLED: It is well known that maternal fibrinogen (Fg) and factor X III are essential for maintaining early pregnancy. We studied their role by analysis of clinical reports and immunohistochemical investigation. METHODS: (1) We analyzed the pregnancy cases of congenital afibrinogenemia and congenital factor X III deficiency. (2) Immunohistochemical staining of Fg, subunit A of factor X III (X IIIA) and fibronectin (Fn) were performed in the human implantation site, placenta, and endometrial cells cultured in serum-free medium. RESULTS: (1) Afibrinogenemia needed to be administrated Fg from 4 weeks' gestation (4 wG), and factor X III deficiency needed factor X III concentrate from 5 wG, in order to prevent abortion. (2) Implantation tissues: Fg, cellular X IIIA and Fn were present at the decidual stroma around invasive cytotrophoblasts at 5 wG. X IIIA-positive cells coincided with LN-5-positive macrophages. Placenta: Fg, cellular X IIIA and Fn were present in the decidual layer. Endometrial culture cells: Fn was secreted by spindle-like shaped cells. X IIIA was secreted by round-shaped cells. CONCLUSION: Maternal Fg and factor X III are essential just after 4-5 wG, and in that period they and Fn are present abundantly in decidual stroma around invasive cytotrophoblasts. It is concluded that when cytotrophoblasts invade endometrium maternal Fg, factor X III and Fn are concerned with cytotrophoblasts' anchoring as adhesive proteins.

Abortion, Spontaneous↗
PubMed1998

Expression of thrombomodulin in atherosclerotic lesions and mitogenic activity of recombinant thrombomodulin in vascular smooth muscle cells.

Thrombomodulin (TM), a thrombin receptor protein found on the endothelial cell surface, contains 6 tandem epidermal growth factor (EGF)-like structures. Recombinant human TM peptide containing these 6 EGF-like domains (rTME1-6) exhibits mitogenic activity in Swiss 3T3 cells. We examined the localization of TM in atherosclerotic lesions and the effects of rTME1-6 on the growth of cultured rat vascular smooth muscle cells (SMCs). Immunohistochemical analysis demonstrated that TM antigen was localized on monocytes, macrophages, and vascular SMCs. In cultured vascular SMCs, rTME1-6 accelerated [3H]thymidine uptake into DNA in a dose-dependent manner up to 3.4 times the control level. This mitogenic activity was abolished by addition of polyclonal anti-human TM antibody. The rTME1-6-induced mitogenesis was enhanced by EGF. However, a neutralizing monoclonal antibody against the EGF receptor (monoclonal antibody 225) did not inhibit the mitogenic activity of rTME1-6. Calphostin C, a specific protein kinase C inhibitor, and lavendustin-A, an inhibitor of EGF receptor-specific protein tyrosine kinase, inhibited the mitogenic activities of both rTME1-6 and EGF. Finally, rTME1-6 treatment increased the level of phosphorylated mitogen-activated protein kinase in SMCs. Together, these results suggest that TM expression in atherosclerotic lesions may be associated with promotion of atherosclerosis through its mitogenic activity in vascular SMCs.

Aged↗