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Biomedical subjects

O Yamada

Publications and source records attributed to O Yamada.

At least 37 records · Page 2Linked to original sources

Referral and care for acute ischemic stroke in a Japanese tertiary emergency hospital.

To examine the current emergency referral and care for acute stroke at a Japanese tertiary emergency hospital with a 24-h stroke team and care unit, we surveyed the presentations of patients with acute ischemic stroke or transient ischemic attack (TIA) seen within 7 days of onset. Delay from symptom onset to arrival at our hospital, from arrival to initial diagnostic brain computed tomography (CT), and the type of anti-thrombotic treatments were evaluated. During the 18-month period, there were 254 ischemic events in 244 patients; 239 (94%) had an ischemic stroke and 15 (6%) TIA. Eighty-two (32%) events presented within 3 h of onset, and 102 (40%) and 179 (70%) within the first 6 and 24 h, respectively. The median delay from hospital arrival to CT was 32 min, ranging 10 min to 22 h. Two hundred (79%) events underwent CT within 1 h of arrival (n=172) or at the referral hospitals before transfer (n=28). Direct ambulance transportation and more severe neurological deficits were independent predictors both for early arrival and short in-hospital delay to CT. Anti-thrombotic therapies including anticoagulant and/or antiplatelet medications were given in 237 (93%) episodes. Two (1%) patients received thrombolysis, although 18 (7%) patients fulfilled the National Institute of Neurological Disorders and Stroke guidelines for intravenous thrombolysis with tissue plasminogen activator. As in western communities, our pre-hospital emergency referral systems for acute stroke require substantial improvements including the wider use of ambulance calling. Although our in-hospital stroke management is functioning relatively well, further efforts are necessary in reducing the diagnostic delay.

Acute Disease↗

Granzyme-B-containing lymphocyte involvement in epidermal injury in graft-versus-host disease.

BACKGROUND: Skin lesions from graft-versus-host disease (GVHD) show histological features of epidermal cell death with lymphocyte infiltration. Perforin and granzyme B are involved in the process of apoptosis induced by cytotoxic T lymphocytes (CTL). OBJECTIVE: To elucidate the role of CTL in the mechanism of epidermal injury in GVHD. METHODS: We studied immunohistochemical staining for granzyme B and perforin in the skin lesions of 8 patients who developed GVHD after bone marrow transplantation. RESULTS: Granzyme-B-positive lymphocytes were CD8 positive and were observed in the epidermis of 3 out of 6 specimens in acute GVHD, and of 5 specimens of chronic GVHD except for 1 sclerotic type in which it was negative. Perforin-positive lymphocytes were observed in the epidermis of the specimens from 1 acute and 1 chronic GVHD. CONCLUSIONS: Granzyme B derived from CTL may be involved in the mechanisms of epidermal injury in GVHD.

Acute Disease↗

Factors affecting psychiatric nurses' intention to leave their current job.

Using the National Institute for Occupational Safety and Health job stress questionnaire, the authors examined psychiatric nurses' intention to leave their job in relation to their perceived risk of assault, their job satisfaction, and their supervisory support. Respondents were 1,494 nurses (response rate, 76.5 percent) employed in 27 psychiatric hospitals in Japan. Forty-four percent reported intention to leave their job, and 89 percent of those perceived a risk of assault. Younger age, fewer previous job changes, less supervisory support, lower job satisfaction, and more perceived risk of assault were significant predictors of intention to leave. Organizational efforts are necessary to retain frontline professional staff.

Adult↗

Imbalance of cusp width and aortic regurgitation associated with aortic cusp prolapse in ventricular septal defect.

The Doppler echocardiograms of the aortic valve and associated aortic regurgitation (AR) were reviewed in 72 patients with a ventricular septal defect (VSD). Group I comprised 13 patients without any deformity of the aortic cusp for > or = 10 years, group 2 included 35 patients who did not develop AR for > or = 10 years after right coronary cusp prolapse (RCCP) was first detected, group 3 comprised 11 patients with RCCP and AR in whom the AR remained subclinical for > or = 10 years, and group 4 was 13 patients who underwent surgical treatment because of moderate to severe AR. The cusp imbalance index [width of right (R) or non- (N) coronary cusp/width of left coronary cusp (L)] was compared among the 4 groups. R/L or N/L was larger in group 4 than in groups 1-3; R/L exceeded 1.30 in all the patients in group 4, whereas it was less than 1.30 in all the atients in groups 1-3. Two patients in group 4 with non-coronary cusp prolapse had an N/L greater than 1.50. No other patients in any group had an N/L larger than 1.20. An imbalance of cusp width may predict possible progressive deterioration of AR.

Adolescent↗

Life-threatening pulmonary edema following unilateral stent implantation for bilateral branch pulmonary stenosis: recovery after contralateral stent implantation.

A 13-year-old girl, who was suffering complications with bilateral pulmonary artery stenosis after intracardiac repair for tetralogy of Fallot, suffered life-threatening left pulmonary bleeding and edema following inadvertent unilateral stent implantation for a left pulmonary stenosis. Pulmonary edema and subsequent hypoxia persisted despite intensive medical treatment; however, contralateral stent deployment resolved her symptoms quickly.

Adolescent↗

Expression and in vitro modification of parathyroid hormone-related protein (PTHrP) and PTH/PTHrP-receptor in human myeloma cells.

To elucidate the role of PTHrP in myeloma, we examined the expression levels of PTHrP and its receptor in human myeloma cell lines and clinical specimens from 13 myeloma cases. In vitro modification of PTHrP expression and production induced by TGF-beta and PMA in PTHrP expressing myeloma cell lines was also investigated. PTHrP expression was detected in six out of seven myeloma cell lines with an inverse correlation with the expression of its receptor, and in 10 out of 13 clinical specimens in varying degrees. The PTHrP expression and secretion into culture medium were enhanced by supplemental TGF-beta and PMA. PMA also seemed to affect PTHrP upregulation via TGF-beta activation. The fundamental role of PTHrP in bone lesions and hypercalcemia in myeloma may be important to consider even during the initial phase of the disease and particularly in the progression of bone complications with hypercalcemia.

Aged↗

Establishment of CD7+ human myeloma sister cell lines, KMS-21-PE and KMS-21-BM, carrying t(11;14) and t(8;14).

Two new human myeloma cell lines were established from pleural effusion and bone marrow malignant cells derived from a single patient, who manifested hyperammonemia associated with multiple myeloma, and these were characterized. Both lines possess t(11;14)(q13;q32) and t(8;14)(q24;q32) reciprocal translocations and overexpress cyclin D1, but not c-myc. Human myeloma lines including these new lines produced and secreted excess ammonia into culture medium more than non-myelomatous hematological cell lines. In addition, these two lines were revealed to have high surface CD7 expression correlated with relatively high mRNA expression by MP-RT-PCR. Among 8 human myeloma lines, half of them revealed significant surface expression of CD7 and a positive correlation between expression levels of protein and message. CD7 message was also detected in surface negative lines. Consequently, there may be posttranslational regulation of the CD7 molecule, whose cellular biological role in expressing cells has not been elucidated.

Adult↗

Diastereoselective synthesis of 3,4-dimethoxy-7-morphinanone: a potential route to morphine.

[reaction: see text] Diastereoselective synthesis of racemic 3,4-dimethoxy-7-morphinanone from racemic 2-(2,3-dimethoxyphenyl)cyclohexen-1-ol has been achieved. The relative structure has been determined by transformation of the product into the known 3, 4-dimethoxy-6-morphinanone. Resolution of the starting cyclohexenol has also been accomplished for use in a future enantiocontrolled synthesis of morphine.

Morphine↗

Evolution of aortic regurgitation following simple patch closure of doubly committed subarterial ventricular septal defect.

We reviewed the Doppler echocardiographic findings of the aortic valve and associated aortic regurgitation (AR) in 55 patients who underwent patch closure of doubly committed subarterial ventricular septal defect (VSD). The maximal diameter of the VSD measured > or = 5 mm, whereas the postoperative follow-up interval was > or = 5 years. Twenty-three patients underwent closure before they developed aortic cusp prolapse or AR (group A). In 15 patients the VSD was closed when aortic cusp prolapse was recognized, but AR was absent (group B). Aortic cusp prolapse with AR was detected before closure in a further 15 patients (group C). Of 8 patients with no AR before closure, AR was detected during follow-up in 6 group A and in 2 group B patients. In group C, AR resolved after surgery in 4 patients, whereas AR grade improved in a further 8 patients and remained unchanged in 3. Although residual AR was more frequent in patients with aortic cusp prolapse and AR before closure, it was silent and asymptomatic.

Adolescent↗

A novel nonviral vector based on vesicular stomatitis virus.

Here we report a simple and efficient method for nonviral gene transfer using liposomes which have envelope protein of vesicular stomatitis virus (VSV) on their surface (VSV-liposomes). We prepared VSV-liposome by fusing simple liposomes with VSV particles. The density of VSV-liposome fusion products was intermediated between that of liposomes and that of VSV particles. Furthermore, VSV-liposome fusion products included both viral proteins and lipids from liposomes, and were confirmed to be fusion products, but not adsorptive products, by the resonance energy transfer fusion assay. To evaluate whether these particles can efficiently introduce their internal contents into the cytoplasm of mammalian cells, we examined the delivery of fragment A of diphtheria toxin (DTA) by VSV-liposomes into the cytoplasm of FL cells. We found that VSV-liposomes encapsulating DTA were highly cytotoxic to the cells, while empty VSV-liposomes and plain liposomes encapsulating DTA were not, suggesting that VSV-liposomes delivered DTA into cytoplasm. Consistent with this, the cells cultured with plasmid DNA entrapped in VSV-liposomes and coding for firefly luciferase showed significant luciferase expression, whereas cells culture with plasmid DNA in plain liposomes and plasmid DNA-cationic liposomes complex did not. Thus, VSV-liposomes function as a simple and efficient nonviral vector for the delivery of DNA.

Gene Transfer Techniques↗

Estrogen receptors in human myeloma cells.

It has recently been reported that the human myeloma cell line U266 proceeds to undergo apoptosis after cultivation with the antiestrogen tamoxifen, thus raising the possibility that antiestrogens may be candidates for use in myeloma therapy. To obtain basic information on the effects of antiestrogens on myeloma cells, we investigated the mRNA expression levels of estrogen receptor (ER)-alpha, ER-beta, and coactivators and corepressors in nine human myeloma cell lines and compared them with those of seven human breast cancer cell lines including four ER-positive and three ER-negative lines. The alterations in cell growth and mRNA expression of the target genes of ER or those of cytokines in the myeloma lines by estradiol or antiestrogens (tamoxifen and toremifene) were also investigated. In addition, effects on membrane Fas expression, appearance of apoptosis, and cell cycle perturbation were analyzed. It was revealed that ER-beta and corepressors were dominantly expressed in myeloma cells, and antiestrogens induced growth inhibition through apoptosis mediated by a Fas-related pathway and G1 arrest of the cell cycle in myeloma cell lines.

Antineoplastic Agents, Hormonal↗

Nasal NK/T cell lymphoma presenting as transverse myelopathy.

A case of nasal NK/T cell lymphoma with central nervous system (CNS) involvement is reported. A 56-year-old man presented with eyelid edema and transverse myelopathy. Cerebrospinal fluid examination revealed atypical lymphoid cells with azurophilic granules, which were positive for CD2, CD8, and CD56, and negative for CD3 and CD5 by flow cytometry. Because a tumor mass was found involving the ethmoid and maxillary sinuses, CNS involvement was considered to have resulted from local invasion by the nasal lymphoma. In spite of intensive chemotherapy including intrathecal infusion, the patient died 6 months after the initial diagnosis. Autopsy revealed that lymphoma cells were positive for cytotoxic molecules, granzyme B and TIA-1, and EB virus-encoded RNA-1 (EBER-1), and they showed no rearrangement of TCR-beta, -gamma, or -delta genes, suggesting an NK-cell origin of the lymphoma cells. They showed an angiocentric and angiodestructive pattern in the subarachnoid space, focally extending to the cerebral cortex and cranial and spinal nerve roots. Marked demyelination was found in the lateral and posterior funiculi of the spinal cord. Thus, the pathogenesis of this spinal demyelination might be attributed to ischemia secondary to angiocentric and angiodestructive infiltration by lymphoma cells.

Diagnosis, Differential↗

Shortening of telomeres in recipients of both autologous and allogeneic hematopoietic stem cell transplantation.

Telomere length of peripheral blood mononuclear cells (PBMCs) from 23 autologous HSCT patients ranging from 4 to 61 years old, and 46 allogeneic HSCT recipients from 6 to 52 years old were studied to confirm whether excessive shortening of telomeres is associated with HSCT. After autologous HSCT, telomere length of PBMCs ranged from 6.8 to 12.0 kb. The comparison between transplanted PBMCs and PBMCs after autologous HSCT showed shortening by up to 1.9 kb (mean +/- s.d.: 0.64 +/- 0.50 kb). There was a difference between autologous HSCT patients and normal volunteers in the slopes of regression lines. After allogeneic HSCT, telomere length of PBMCs ranged from 6.8 to 12.0 kb. Telomeres of recipients were up to 2.1 kb (0.60 +/- 0.468 kb) shorter than those of donors. The slope of regression lines for allogeneic HSCT patients and normal volunteers were parallel. Although all patients were transplanted with more than 2.0 x 10(8) cells/kg, telomere length did not correlate with the number of transplanted cells. There was no significant correlation between telomere length and recovery of hematological parameters. However, three patients with an average telomere length of 6.8 kb after HSCT took a longer period to reach the normal hematological state. Taken together, these data suggest that most HSCTs are performed within the biological safety range of telomeres, while the patients who have telomeres shorter than 7.0 kb after HSCT should be observed carefully for long-term hematopoiesis and the occurrence of hematopoietic disorders.

Adolescent↗

Ectopic expression of c-myc fails to overcome downregulation of telomerase activity induced by herbimycin A, but ectopic hTERT expression overcomes it.

Telomerase plays a key role in the maintenance of chromosomal stability in tumors, but the mechanism regulating telomerase activity is still unclear. Recent studies have suggested that c-myc may be vital for regulation of hTERT mRNA expression and telomerase activity. In this study, we investigated the changes of telomerase activity and telomerase-related genes induced by herbimycin A in K562 human chronic myelogeous leukemic cells. Telomerase activity showed a biphasic pattern in herbimycin A-treated K562 cells. Initially, the telomerase activity decreased along with the decline of cells in S and G2/M phases, but it recovered slightly at the end of treatment. Expression of mRNA for the telomerase catalytic subunit (hTERT) was decreased before the decline of telomerase activity, and increased slightly before the reactivation of telomerase activity. During herbimycin A treatment, both c-myc and cyclin D1 mRNA showed transient downregulation before the increase of G1 cells. Herbimycin A treatment caused the downregulation of both telomerase activity and hTERT mRNA in cyclin D1-transfected K562 cells, while telomerase activity was partially restored in c-Myc-transfected cells. In contrast, hTERT-transfected K562 cells maintained a high level of telomerase activity during herbimycin A treatment. Neither the template RNA component of telomerase (hTERC) nor telomerase-associated protein (TEP-1) were altered in any of the transfected K562 cells. These results indicate that telomerase activity is mainly regulated by hTERT, and that c-Myc protein is one of the positive regulators of hTERT in leukemic cells but is not enough to counteract the downregulation of telomerase activity by herbimycin A completely.

Benzoquinones↗

Primary pericardial mesothelioma presenting as constrictive pericarditis: a case report.

Primary malignant pericardial mesothelioma is a rare tumor and the case reported here presented as constrictive pericarditis. The patient's symptoms progressed day by day despite treatment with digitalis, diuretics and catecholamines. Although a computed tomographic scan of the chest, echocardiography and pericardiocentesis were performed, a preoperative definitive diagnosis could not be obtained. Emergency pericardiectomy and partial resection of the tumor were carried out with the aid of a percutaneous cardiopulmonary supporting system, but the patient died of cardiac failure on postoperative day 3. The tumor appeared to be the biphasic type of diffuse malignant mesothelioma. The prognosis for pericardial mesothelioma is extremely poor due to its late presentation and difficulty in completely removing it surgically and, unfortunately, there still is not a radical therapy for this tumor.

Diagnosis, Differential↗

Cellular biological differences between human myeloma cell lines KMS-12-PE and KMS-12-BM established from a single patient.

To clarify cellular biological varieties of myeloma cells, biological differences were analyzed between 2 human myeloma cell lines, KMS-12-PE and KMS-12-BM, derived from pleural effusion and bone marrow, respectively, of a single patient. Although both lines were considered to be derived from the same clone because both had the same chromosomal marker and immunoglobulin H rearrangement, several biological differences were noted. CD11a and CD20 were highly expressed in the KMS-12-BM line, whereas the KMS-12-PE line showed a higher expression of CD7 and CD95/Fas. Although growth was stimulated in KMS-12-BM by interleukin-6 and interferon-alpha, it was inhibited in KMS-12-PE. In addition, apoptosis inhibitors Bcl-2 and Bcl-X(L) were highly expressed in KMS-12-BM cells. Because KMS-12-PE was cultivated 2 months before KMS-12-BM, these differences might be related to their origin (pleural effusion and bone marrow) or the phases of disease progression. However, these biological differences may help clarify myeloma cell biology and lead to improvement in treatment for myeloma patients.

Antigens, Surface↗

Expression and production of interleukin 10 in human myeloma cell lines.

Recent investigations of the cytokine network surrounding myeloma cells have disclosed the importance of gp130-related cytokines including interleukin (IL)-6 for myeloma cell survival and proliferation, identification of IL-10 as a growth factor for myeloma cells, the close relationship between IL-10 and the receptors for gp130-related cytokines, and the growth enhancement effect of IL-11 and IL-7 on myeloma cells. In this study, IL-10 production was observed in three out of seven human myeloma cell lines examined and five (including three producing lines) out of 10 lines exhibited mRNA expression of IL-10. The IL-10 mRNA expression was also enhanced in approximately one third of primary specimens, whereas the IL-10 receptor (R) expression was not changed compared with that of normal component marrow controls. However, reverse transcription-polymerase chain reaction (RT-PCR) assay of various cytokines and their receptors showed no particular association with IL-10-producing myeloma lines compared with non-producing lines. Supplementing exogenous IL-10 or neutralization of the IL-10 signal by anti-IL-10 monoclonal antibody (mAb) in a culture conditions did not significantly affect myeloma cell growth regardless of expression of IL-10 or its receptor (IL-10R). However, supplement of anti-IL-10 mAb caused upregulation of certain genes such as IL-11, leukaemia inhibitory factor receptor (LIFR) and syndecan-1 in IL-10R-expressing cell lines. These findings indicate that the cytokine network surrounding myeloma cells is complicated and variable. In addition, IL-10 may modify this network and the cellular biological properties of myeloma cells rather than cell proliferation.

Actins↗