Search PubMed⌕ Search

Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 55 records · Page 3Linked to original sources
PubMed2003

The phenotype of normal tension glaucoma patients with and without OPA1 polymorphisms.

AIM: Polymorphisms in OPA1, the gene responsible for autosomal dominant optic atrophy, were recently found to be strongly associated with normal tension glaucoma (NTG). The aim of this study was to determine whether OPA1 polymorphisms affect the phenotype of NTG patients. METHODS: A retrospective analysis was performed of 108 well characterised NTG patients who had been genotyped for OPA1 variations, and who had previously undergone automated perimetry and Heidelberg retina tomography (HRT). 25 NTG patients had the at-risk OPA1 genotype (IVS 8 +4 C/T; +32 T/C) and 83 NTG patients did not. Differences between groups were sought in a wide range of structural, psychophysical, and demographic factors. These included sex, age at diagnosis, family history of glaucoma, history of ischaemic risk factors and vasospasm, laterality of glaucoma, presenting and highest diurnal intraocular pressure (IOP), initial cup-disc (CD) ratio, baseline visual field global indices, and optic disc parameters as measured by HRT. For a subgroup of patients with at least 5 years of follow up and 10 visual field tests, pointwise linear regression analysis (PROGRESSOR for Windows software) was applied to the visual field series. RESULTS: There was no significant difference in the two groups with respect to sex, age at diagnosis, family history of glaucoma, history of ischaemic risk factors and vasospasm, or laterality of glaucoma. The comparison of IOP, CD ratio and visual field global indices, MD and CPSD in the two groups showed no significant difference. There were no differences in the mean values for any of the HRT parameters analysed. For the subgroup of patients with at least 5 years of follow up, there was also no significant difference in the number of patients with progressing locations, the mean number of progressing locations per subject, the mean slope of the progressing locations or the mean slope for whole visual field. CONCLUSIONS: The absence of phenotypic differences in normal tension glaucoma patients with and without the OPA1 polymorphisms IVS 8 +4 C/T; +32 T/C suggest that these OPA1 polymorphisms do not underlie any major phenotypic diversity in these patients.

Age of Onset↗
PubMed2003

Osteosarcoma with cytokeratin expression: a clinicopathological study of six cases with an emphasis on differential diagnosis from metastatic cancer.

AIMS: To clarify the clinicopathological profile of osteosarcomas showing an intensely positive immunoreaction for cytokeratin. METHODS: Clinicopathological and immunohistochemical features were analysed in 131 patients with non-metastatic, conventional osteosarcoma, treated in Akita University and National Cancer Centre in Tokyo between 1972 and 1999. RESULTS: Six patients (4.5%; mean age, 32 years; four men, two women) had osteosarcomas showing intense cytokeratin expression. Tumours were located on the long bones of the extremities in five patients and the ilium in one. Osteoid formations were found in biopsied specimens in all cases. Three tumours were classified as osteoblastic osteosarcoma, two as fibroblastic, and one as chondroblastic. In three tumours classified as the osteoblastic subtype, epithelioid features were prominent, and four tumours showed pronounced cellular pleomorphism. In contrast to the expression of cytokeratin, epithelial membrane antigen was negative in all cases. Surgery with a wide excisional margin was performed in six patients. Preoperative and postoperative chemotherapy was given to five of the six patients, but the effects of these agents were negligible. Three of the six patients developed lung metastases, whereas the other three patients have remained well with no evidence of local recurrence or distant metastasis. CONCLUSIONS: Osteosarcoma with intense immunoreaction for cytokeratin was rare. The clinicopathological features were similar to those of patients with conventional osteosarcoma, except for a higher age, chemotherapy resistance, histological epithelioid features, and pleomorphism. This study indicates that osteoid formation and negative expression of epithelial membrane antigen are key features in the differentiation from metastatic carcinoma.

Adolescent↗
PubMed2003

Prognostic relevance of rosette-like features in osteosarcoma.

AIMS: To clarify the prognostic relevance of rosette-like features and other clinicopathological and immunohistochemical variables in patients with osteosarcoma. METHODS: Clinicopathological and immunohistochemical variables were analysed in 131 patients with non-metastatic high grade conventional osteosarcoma, with particular attention to the prognostic impact of rosette-like features. RESULTS: Rosette-like features were present in 18 (14%) cases. Rosette-like features were significantly associated with the osteoblastic subtype, numerous osteoclast-like giant cells, moderate pleomorphism, frequent haemangiopericytoma-like vascular patterns, epithelioid cytological features, positive immunoreactivity for epithelial membrane antigen and CD56, and negative staining for cytokeratin. In a multivariate analysis, rosette-like features (relative risk (RR), 3.8), a poor chemotherapy effect (RR, 2.9), and a tumour size of 10 cm or more (RR, 2.8) were identified as unfavourable prognostic factors. CONCLUSIONS: Rosette-like features can easily be identified from routine histological slides and the relative risk in patients with non-metastatic, conventional osteosarcoma is as high as other well known prognostic factors, including large size and poor chemotherapy effect.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Adenoviral gizzard erosion in commercial broiler chickens.

Pathologic and immunohistochemical changes caused by group I of the fowl adenovirus (FAV) serotype-1 99ZH strain, isolated from broiler chickens exhibiting gizzard erosion, were investigated in commercial broiler chickens. One hundred twenty-two chickens were inoculated with the strain by both oral and ocular routes at 1, 3, or 5 weeks of age and euthanatized for necropsy within 4-18 days of inoculation. Focal gizzard erosions were observed in the inoculated chickens of each age group. A histologically degenerative koilin layer, necrotic mucosa, intranuclear inclusion bodies in the glandular epithelial cells, inflammatory cell infiltrations in the lamina propria, submucosa, and a muscle layer were seen in the gizzards. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies. These findings were recognized regardless of their maternal antibody levels for FAV serotype-1. Gizzard lesions appeared later in the lower-dose-inoculated chickens than in the higher-dose-inoculated chickens. Numerous CD3-positive cells and IgY-positive plasma cells were seen in the gizzard lesions. In 5-week-old chickens the heterophil infiltrations in the lesions were milder than in younger chickens. Intranuclear inclusion bodies also were observed in the epithelial cells of the ileum or cecal tonsils of some chickens. Thus, this study shows that FAV-99ZH causes adenoviral gizzard erosion in broiler chickens without hepatic or pancreatic lesions and that cell infiltration is more severe than in dietary gizzard erosions.

Adenoviridae Infections↗
PubMed2002

Cyclopentadithiophene (CPDT) dimer dication: bipolaron model for quaterthiophenes.

[structure: see text] Cyclopentadithiophene (CPDT) dimers in which both 3,3' and 4' ',3' " positions were bridged with 1,3-dioxalane, carbonyl, or dicyanovinylidene were prepared. These compounds have small HOMO-LUMO gaps (1.03-2.25 eV). The electrochemical oxidation of a dicyanovinylidene-bridged CPDT dimer gave a dication that had a quinoid-like structure.

Journal Article↗
PubMed2002

TRIPTYCHON and CAPRICE mediate lateral inhibition during trichome and root hair patterning in Arabidopsis.

Trichome patterning in Arabidopsis is a model for the generation of a spacing pattern from initially equivalent cells. We show that the TRIPTYCHON gene that functions in lateral inhibition encodes a single-repeat MYB-related transcription factor that lacks a recognizable activation domain. It has high sequence similarity to the root hair patterning gene CAPRICE. Both genes are expressed in trichomes and act together during lateral inhibition. We further show that TRIPTYCHON and CAPRICE act redundantly in the position-dependent cell fate determination in the root epidermis. Thus, the same lateral inhibition mechanism seems to be involved in both de novo patterning and position-dependent cell determination. We propose a model explaining trichome and root hair patterning by a common mechanism.

Arabidopsis↗
PubMed2002

Symmetry-dependent multielectron excitations near the C 1s ionization threshold and distortion of the shape resonance in CO(2).

Satellite bands accompanying the C 1s photoline for the CO2 molecule parallel to the electric vector of the incident radiation E are found to be more intense than those for CO2 perpendicular to E in the shape resonance region. This indicates that multielectron excitations are caused in part by the interaction of the outgoing C 1s photoelectron with the valence electrons. The photoelectron-impact valence excitations couple with the C 1s single-hole ionization and distort the shape resonance significantly. We assign the broad resonance at approximately 312 eV to a distorted Sigma(u) shape resonance.

Journal Article↗
PubMed2002

Insulin-like growth factor I enhances gonadotropin-releasing hormone-stimulated luteinizing hormone release from bovine anterior pituitary cells.

The role of insulin-like growth factor I (IGF-I) in the release of luteinizing hormone (LH) is unclear in ruminants. In the present study, the effects of IGF-I on the release of LH stimulated by gonadotropin-releasing hormone (GnRH) were examined in primary cultures of bovine anterior pituitary (AP) cells, and the interaction between estradiol-17beta (E(2)) and IGF-I was characterized. GnRH(100nM)-stimulated LH release from the cultured cells was increased (P<0.05) 12, 24 and 36h after addition of IGF-I (250ng/ml), with a maximum at 12h (48.4ng/ml media versus 35.4ng/ml media in controls). IGF-I at concentrations of 25, 250 and 500ng/ml increased the release by 18.7, 24.2 and 28.9%, respectively (P<0.05), when compared with controls (37.2ng/ml media). E(2) (10nM), IGF-I (250ng/ml) and combined treatment of E(2) plus IGF-I also induced significant increases in LH release (P<0.05). The amounts of LH release after treatment with E(2) alone was 37.3% greater than with IGF-I alone (39.0ng/ml media versus 28.4ng/ml media) (P<0.05). When E(2) and IGF-I were added together (45.6ng/ml media), the release of LH was significantly greater than with either E(2) alone or IGF-I alone (P<0.05). E(2) (10nM) significantly (P<0.05) increased the amount of GnRH bound to the cells by 51.6% when compared with controls, however, IGF-I (250ng/ml) failed to increase GnRH binding. These results show that IGF-I enhances GnRH-stimulated LH release without changing the number of GnRH receptors in cattle, and IGF-I interacts with E(2) to increase the response to GnRH.

Animals↗
PubMed2002

Symmetry-resolved vibrational spectroscopy for the C 1s(-1)2 pi(u) Renner-Teller pair states in CO(2).

Symmetry-resolved excitation spectra have been measured for the Renner-Teller pair states A(1) and B(1) split from the core-excited C 1s(-1)2 pi(u) state in CO(2). A vibrational progression with the spacings of approximately 145 meV is found in both the A(1) and B(1) spectra at different energies and assigned to the symmetric stretching mode caused in the B(1) linear state, with the help of ab initio calculations. Appearance of the vibrations in the A(1) spectrum is interpreted as due to non-adiabatic coupling between the A(1) and B(1) states via the bending motion.

Journal Article↗
PubMed2002

A novel autoimmune pancreatitis model in MRL mice treated with polyinosinic:polycytidylic acid.

In this study we established a new animal model for exploring the pathogenesis of autoimmune pancreatitis. We have found previously that MRL/Mp-+/+(MRL/+) mice develop pancreatitis spontaneously by an autoimmune mechanism but only when they are more than 34 weeks old. Because this disease might be a model of multi-factorial diseases controlled by genetic and environmental factors, beginning at 6 weeks old, we injected polyinosinic:polycytidylic acid (poly I:C) into MRL/+ mice and in addition, into MRL/Mp mice bearing the Fas deletion mutant gene, lpr (MRL/lpr). Poly I:C induced chronic severe pancreatitis in all the MRL/+ mice and to a lesser extent in the MRL/lpr mice by 18 weeks of age. There was no pancreatitis in control mice of both strains at the same age. Other than chronic pancreatitis, no severe autoimmune diseases were observed in MRL/+ mice. Immunohistochemical examinations revealed predominant infiltration of CD4+ T cells and Mac-2+ activated macrophages in the pancreatic lesions. Splenic expression of the mRNAs for TNF-alpha and IL-10, which is known to suppress the development of pancreatitis, were increased in both strains of mice. These findings suggest that an MRL strain of mice treated with poly I:C might be a good model for developing new approaches to the study of the pathogenesis of autoimmune pancreatitis.

Age Factors↗
PubMed2002

Invasive pulmonary aspergillosis resulting in respiratory failure during neutrophil recovery from postchemotherapy neutropenia in three patients with acute leukaemia.

Respiratory failure is a severe complication of invasive pulmonary aspergillosis (IPA). Its pathogenesis is not well understood. We herein describe three cases of subacute respiratory failure that occurred during the recovery phase of neutropenia following induction chemotherapy for acute leukaemia with IPA. In each case, severe neutropenia (19-85 days), high-grade fever, severe anaemia, the use of granulocyte-colony-stimulating factor and increasing infusion volume were noted. As the neutrophil count was recovering, the shadows on the chest X-ray expanded with progressing hypoxia. We should pay attention to the respiratory failure during the recovery phase of neutropenia in patients with IPA.

Acute Disease↗
PubMed2002

Preliminary thermographic evaluation of new nitroglycerine tape on the peripheral circulatory disturbance in systemic sclerosis.

OBJECTIVE: To evaluate the effects of newly developed nitroglycerine (NTG) tape on the peripheral circulatory disturbance in systemic sclerosis (SSc). METHODS: The finger temperature (FT) of 25 patients with SSc was monitored by thermography before the application of NTG tape to the wrist and one hour afterwards. To check the placebo effect, the change of FT with placebo tape in six patients who had shown a distinct rise in FT (>2 degrees C) with NTG tape was monitored. RESULTS: Twenty one patients with SSc had a low FT before the application of NTG tape (colder than mean-2SD of normal controls). FT was significantly raised in patients with SSc after the application of NTG tape (p<0.01). Patients with low FT showed a distinct rise in FT more often than patients with a normal FT (71% v 0%, p<0.01). FT was raised with NTG tape more than with placebo tape (4.2 (SD 1.9) degrees C v 2.2 (2.8) degrees C, p<0.05). CONCLUSION: The application of NTG tape increases peripheral circulation in patients with SSc who have distinct circulatory disturbance. The application of NTG tape may improve peripheral circulatory disturbance in SSc.

Administration, Cutaneous↗
PubMed2002

[Cases of death after surgery for pathologic stage I non-small cell lung cancer].

We clinically examined cases of death from pathologic stage I non-small cell lung cancer with the aim of improving the 5-year survival rate after surgery for this condition. The subjects were 70 patients with p-stage IA (20 cases of death) and 59 patients with p-stage IB (26 cases of death) from among those who underwent surgery for p-stage I non-small cell lung cancer between 1986 and 2000. 1) Of 30 patients who died from p-stage I lung cancer, 20 had distant metastases and 10 had recurrence in the thoracic cavity. Of 16 patients who died from other diseases, 5 had respiratory organ disease, 5 had cancers of other organs and 6 had circulatory organ disease. 2) Of 30 patients who died from p-stage I lung cancer, 20 (66.7%) had distant metastases, with lung metastasis occurring most frequently, in 10 of them (33.3%). The most common cause of death of patients with p-stage IB lung cancer was recurrence in the thoracic cavity. 3) The mean durations of survival (mean +/- standard deviation) after surgery for lung cancer of the patients who died from p-stage I lung cancer (30 patients) were 36.3 +/- 22.2 months for the 20 patients with distant metastases and 26.2 +/- 14.3 months for the 10 patients with recurrence in the thoracic cavity, the difference between groups was 10 months, but was not significant. 4) The 5-year survival rate in 45 patients who underwent p-stage IA mediastinal lymph node dissection was 83.1% whereas that in 25 patients without p-stage IB mediastinal lymph node dissection was 50.9% showing a significant difference of 32.2% (p < 0.01). 5) The patients in p-stage IA who died from other diseases were all men (10 patients). The mean durations of survival after surgery for lung cancer in the patients who died from other diseases were 35.2 +/- 19.0 months in the patients with respiratory organ disease, 37.0 +/- 23.9 months in those with cancers of other organs and 60 +/- 19.1 months in those with circulatory organ disease. 6) The 5-year survival rate after surgery in all cases of death was 76% in the patients in p-stage IA and 61.4% in those in p-stage IB. The 5-year survival rates in the patients excluding those who died from other diseases were 85% in the patients in p-stage IA (60 patients) and 60.3% in those in p-stage IB (53 patients) (p < 0.01). 7) To improve the 5-year survival rate in the patients with p-stage IA lung cancer, it is necessary to prevent death from other diseases in men. It is still possible to improve the 5-year survival rate in the patients with p-stage IB lung cancer by raising the accuracy of mediastinal lymph node dissection during surgery.

Aged↗
PubMed2002

Intravenous allicin improves pulmonary blood flow after ischemia-reperfusion injury in rats.

BACKGROUND: Allicin is a sulfur-containing compound extracted from garlic, with antiaggregatory, anti- migratory, anti-oxidant and pulmonary vasodilator actions. We hypothesized that allicin might be beneficial in lung ischemia-reperfusion. METHODS: A non-nothermic rat lung ischemia-reperfusion model was established by clamping left pulmonary artery (PA) for 1 hr, followed by reperfusion for 2 hrs by clamping right PA to reflect solely the function of left lung. Groups were control (n=7), allicin 0.1 mg (n=8) and allicin 0.01 mg (n=4). In the beginning of reperfusion allicin/saline were injected. Pulmonary artery pressures (PAP), pulmonary artery flow (PAF), left atrial pressure (LAP) were monitored. At the end of reperfusion period arterial blood gas (ABG) analysis was done. RESULTS: Six of 7 control and 3 of 8 group 2 animals died before completing the experiment. In group 1 all animals completed the experiment (p=0.015 vs control). PAF was significantly increased after 30, 60 and 120 min of reperfusion in group 1 (p=0.0028, 0.0009, 0.0003 respectively vs control) and after 60 and 120 minutes in group 2 (p=0.0453, 0.018 respectively vs control). Pulmonary vascular resistance was lower at 30 min in allicin 0.01 mg group (p=0.0017 vs control). PAP was increased after 60 and 120 min of reperfusion in group 1 (p=0.016, 0.0029 respectively vs control) and after 120 min in group 2 (p=0.0104 vs control). CONCLUSIONS: This study shows that allicin improves postischemic PAF in this model. Allicin needs further investigation of potential utility and mechanism(s) of action.

Animals↗
PubMed2002

[Mid-term results of the surgery for aortic arch aneurysm].

One-hundred-one surgeries for aortic arch aneurysm were divided into 2 groups: 52 aortic dissection cases (AD) and 49 non-dissecting aneurysm (TA). In group AD, 30 cases were operated in acute phase (acute AD) and 22 were in chronic phase (chronic AD). Preoperative shock were observed in 21 cases (15 in acute AD mostly due to cardiac tamponade, 1 in chronic AD and 5 in TA due to rupture). Through median sternotomy, 59 total arch replacement and 25 hemi-arch replacement were carried out under deep hypothermia (16 degrees C:DH) and retrograde (RCP) or selective (SCP) cerebral perfusion or arch-first technique. Through thoracotomy, distal arch replacement were carried out with DH + RCP in 8 cases and with partial bypass in 9. Early mortality were observed in 7 patients (6.9%) and 24 months survival rates (Kaplan-Meier) were 86.1% overall, 76.1% in acute AD, 95.5% in chronic AD, 87.8% in TA. The survival rates in patients with preoperative shock was 61.2%, however, without shock, 92.9% in acute AD, 95.2% in chronic AD, and 91.4% in TA. Other than mortality, 4 re-operations for aortic arch, 4 operations for descending to abdominal aorta and 1 late hemiplegia were observed. Aortic event free ratio at 24 months was 55.4% in acute AD, 94.4% in chronic AD, and 75.7% in TA. For the further improvement of aortic arch surgery, early mortality and residual false lumen in acute aortic dissection and atherosclerotic aneurysm in descending to abdominal aorta are focused.

Aged↗
PubMed2002

[Castleman lymphoma originated from the posterior mediastinum resected thoracoscopically: report of a case].

We report thoracoscopic resection of Castleman lymphoma originated from the posterior mediastinum. The patient was a 19-year-old woman, who was pointed out to show an abnormal shadow in the left upper lung in the chest X-ray photograph. It was diagnosed as a blood-rich posterior mediastinal tumor by dynamic MRI, and thoracoscopic surgery was performed. The tumor was adjacent to the vertebral body of the fourth thoracic vertebra. Although operation involved 2 hours and 40 minutes and 670 ml of bleeding due to a strong adhesion between the tumor and the intercostal muscle and considerable bleeding from the tumor itself, it was successfully removed under thoracoscopy. The tumor was elastic and hard, and 50 x 45 x 25 mm in size. The histopathological diagnosis was a Castleman lymphoma, hyaline vascular type. The postoperative course was satisfactory, and the patient was discharged from the hospital on the 7th postoperative day. Castleman lymphoma originated from the posterior mediastinum tends to bleed considerably during its resection. If a blood-rich posterior mediastinal tumor was found preoperatively, thoracoscopic operation must be advanced carefully keeping this disease in mind.

Adult↗