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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effect of protein supplement source on porcine oocyte maturation and subsequent embryonic development after parthenogenetic activation.

The aim of this study was to compare the effect of purified GPBoS and commonly used FCS on porcine oocyte maturation and subsequent embryonic development after their parthenogenetic activation. COCs were obtained from dissected follicles and cultured for 18, 24, 30, 36, 42 and 48 h in M-199 medium either with GPBoS or FCS. After 24 h with GPBoS, 91% of oocytes reached MI stage while in the medium supplemented with FCS, only 29% of oocytes reached the same stage (P < 0.05). The majority of oocytes from the FCS group (61%) reached MI stage approximately 6 h later. In the time periods between 36 to 48 h both groups of oocytes reached the same stage of maturation. After 48 h of culture the oocytes with extruded polar bodies were activated by a single electric pulse and then cultured with 4 mM 6-DMAP. Activated oocytes were cultured in PZM-3 medium supplemented with 3 mg/ml of BSA. After 7 days, the development and the quality of embryos were evaluated. The results showed that the maturation of oocytes in the presence of GPBoS significantly increased their subsequent developmental ability when compared with FCS supplementation (27% vs. 19% of blastocysts, P < 0.05). However, differential staining revealed that once blastocysts were formed in either group, they had the same total cell number (40 vs. 41) and also the ICM/total cell ratio (0.27 vs. 0.29).

Animals↗
PubMed2005

CYP1A1 is a major enzyme responsible for the metabolism of granisetron in human liver microsomes.

Granisetron, a potent 5-HT3 receptor antagonist, has been reported to be mainly metabolized to 7-hydroxygranisetron and a lesser extent to 9'-desmethylgranisetron in humans. A previous study indicated that cytochrome P450 (CYP)3A4 is a major catalyst of 9'-demethylation, although the major CYP isoform(s) responsible for 7-hydroxylation are unknown. To clarify granisetron 7-hydroxylase, the in vitro metabolism of granisetron using expressed human CYPs and human liver microsomes was investigated. 7-Hydroxygranisetron was produced almost exclusively by CYP1A1, while, apparently, 9'-desmethylgranisetron was preferentially produced by CYP3A4. Marked inter-individual differences in the ratio of the formation of 7-hydroxygranisetron and 9'-desmethylgranisetron in human liver microsomes was observed. Granisetron 7-hydroxylase activity was strongly correlated with benzo[a]pyrene 3-hydroxylase activity (p<0.0001), but not with testosterone 6beta-hydroxylase activity in human liver microsomes. Furthermore, an anti-human CYP1A1 antibody completely inhibited 7-hydroxylation in human liver microsomes, however, the reaction was not inhibited at all by an anti-CYP3A4 antibody. On the other hand, granisetron 9'-demethylase activity correlated significantly not only with testosterone 6beta-hydroxylase activity (p<0.0001) but also with benzo[a]pyrene 3-hydroxylase activity (p<0.01). Consistent with this, both the anti-CYP1A1 and anti-human CYP3A4 antibodies inhibited the 9'-demethylase activity. These data indicate that CYP1A1 is a major enzyme responsible for the metabolism of granisetron via a main 7-hydroxylation pathway and an alternative 9'-demethylation route. This is the first report demonstrating the substantial contribution of CYP1A1 to the metabolism of a drug, although its role in the metabolism of environmental compounds is well established.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2004

Hazardous ions uptake behavior of thermally activated steel-making slag.

This study concerns the utilization of waste steel-making slag, a by-product that contains mainly CaO, Fe(2)O(3) and SiO(2). The as-received slag was ground and thermally activated by temperature treatment from 110 to 1000 degrees C for 24 h. Although the as-received slag was amorphous, it became partially crystallized during grinding. These crystalline phases were larnite and iron oxide but other crystalline phases also appeared in addition to larnite after calcination. The uptake of Ni(2+), PO(4)(3-) and NH(4)(+) by the samples was investigated from solutions with initial concentrations of 10 mmol/l. The sample calcined at 800 degrees C showed the highest Ni(2+) uptake (4.85 mmol/g) whereas the highest simultaneous uptake of PO(4)(3-) (2.75 mmol/g) and NH(4)(+) (0.25 mmol/g) was achieved by calcining the material at 700 degrees C. The principal mechanism of Ni(2+) uptake is thought to involve replacement of Ca(2+) by Ni(2+). The mechanism of PO(4)(3-) uptake is mainly by formation of calcium phosphate while that of NH(4)(+) involves sorption by the porous silica surface of the samples.

Ammonia↗
PubMed2004

Probe of bending motion following the 1s(-1)pi* excitation of N2O.

The doubly degenerate core-excited Pi state of N2O splits into two due to the static Renner-Teller effect. The lower state, A1, has a bent stable geometry and the molecule excited to this state starts to deform itself toward this bent geometry. To probe the effect of the potential energy surfaces of the core-excited A1 states on the nuclear motion, we measure the momenta of the three atomic ions in coincidence by means of the ion momentum imaging technique. We find that the potential energy surface affects the molecular deformation significantly. N2O in the terminal N 1s(-1)3piA1 excited state is observed to be bent more than that in the central N 1s(-1)3piA1 excited state. This means that N2O in the terminal N 1s(-1)3piA1 excited state bends faster than that in the central N 1s(-1)3piA1 excited state. When the excitation energy is decreased within the 1s(-1)3pi resonances, the nuclear motion in the A1 states becomes faster. This is interpreted by the notion that the excitation occurs onto the steeper slope part of the potential energy surface of the excited state for the lower excitation energy. The branching ratio of the A1 excitation increases with the decrease in the excitation energy.

Journal Article↗
PubMed2004

Sequential delivery of interferon-alpha gene and DCs to intracranial gliomas promotes an effective antitumor response.

Effective presentation of tumor antigens by dendritic cells (DCs) is considered to be essential for the induction of antitumor T-cell responses. Apoptotic and necrotic tumors have been noted to be a robust antigen source for DCs. Because glioma cells undergo apoptosis after transfection with the type I interferon (IFN) gene and type I IFNs promote the stimulatory activity of DCs, we hypothesized that transfection of glioma cells with type I IFN genes and provision of DCs would promote particularly effective antitumor activity by both facilitating apoptosis of glioma cells and the presentation of the glioma antigens, thereby inducing specific immune responses against glioma cells. We have previously reported the proof of this hypothesis in vitro and in a subcutaneous tumor model. Here we report an extension of this approach in intracranial (i.c.) gliomas using adenoviral IFN-alpha (Ad-IFN-alpha) vector. Mice bearing day-5 i.c. GL261 glioma received sequential intratumoral (i.t.) delivery of Ad-IFN-alpha and bone marrow-derived syngeneic DCs. This treatment prolonged survival in that nine of 17 animals survived long term (> 60 days versus 0 of 10 control animals). Specific CTL activity was demonstrated following this regimen in the cervical lymph nodes, and the therapeutic efficacy was dependent upon CD8+ cells. Furthermore, these animals were protected against subsequent re-challenge with GL261 gliomas. DCs injected i.t. survived in the tumor and migrated into cervical lymph node. In vitro migration assays revealed the ability of DCs to migrate toward the tumor, suggesting that i.t. injected DCs migrate through the glioma. Taken together, this combination of gene therapy and cellular immunotherapy may be an effective future strategy for treating human gliomas.

Adenoviridae↗
PubMed2004

A key factor of translation reinitiation, ribosomal protein L24, is involved in gynoecium development in Arabidopsis.

In polycistronic genes, uORFs (upstream open reading frames) within the 5'-transcript leader sequence of major ORFs may regulate the translation of these major ORFs. In this case, ribosome reinitiates translation at a start codon of downstream ORF after translation termination of uORF. The plant RPL24 (ribosomal protein L24) is a key factor for translation reinitiation of downstream ORFs on the polycistronic cauliflower mosaic virus 35S RNA transcription unit. In the RPL24-deficient mutant of Arabidopsis, short valve (stv), the basal region of the ovary is shortened, whereas the gynophore appears elongated. This phenotype is never seen in known mutants of other ribosomal protein genes, suggesting that RPL24 has a specific role in gynoecium development. Similar phenotypes were observed in the ett (ettin) and mp (monopteros) mutants. Both ETT and MP genes possess uORFs. We examined the hypothesis that these uORFs regulate their downstream major ORFs by a transient expression assay in Arabidopsis mesophyll protoplasts. Our results supported the idea, suggesting that the structural defects of the gynoecium in stv mutants were caused by decreased efficiency of translation reinitiation of ETT and/or MP.

Arabidopsis↗
PubMed2004

Oligoclonal expansion of circulating and tissue-infiltrating CD8+ T cells with killer/effector phenotypes in juvenile dermatomyositis syndrome.

Although triggering by infectious agents and abnormal immune responses may play some role in the pathogenesis of juvenile dermatomyositis syndrome (JDMS), the precise mechanism of muscle destruction and vascular damage is largely unknown. In this study, we tried to elucidate the role of cytotoxic T cells in two patients with JDMS, who were diagnosed based on the characteristic symptoms, laboratory data, MRI findings and electromyographic patterns. Peripheral blood T cell phenotypes were determined by flow cytometry, using mAbs against specific T cell receptor (TCR) Vbetas. Complementarity-determining region3 (CDR3) size analysis was performed by gene scanning of CDR3 polymerase chain reaction (PCR) amplification products specific for each Vbeta. Subsequently, CDR3 nucleotide sequences were obtained after cloning of the predominant products. The distribution of lymphocytes infiltrating the muscle tissue was analysed by immunohistochemistry. In both patients examined, a unique combination of TCR Vbeta repertoires was increased within the CD8+ T cells. These subpopulations expressed a characteristic phenotype, indicating that they are memory/effector T cells with killer functions. At the same time, immunohistological and molecular biological examinations of the biopsied muscle samples revealed that identical CD8+ T cell clones with identical phenotypes/TCR Vbeta infiltrated within the inflammatory tissue, in particular around vessels. These findings indicate that oligoclonal expansion of CD8+ T cells plays a central role in the pathogenesis of muscle injury in the juvenile form of dermatomyositis syndrome and may provide a useful clinical parameter of disease activity and responsiveness to anti-inflammatory therapy.

Antigens, CD↗
PubMed2004

Pathogenicity by parenteral injection of fowl adenovirus isolated from gizzard erosion and resistance to reinfection in adenoviral gizzard erosion in chickens.

The pathogenicity of a serotype-1 fowl adenovirus (FAV-99ZH), which causes adenoviral gizzard erosion by oral inoculation in chickens, was investigated in specific pathogen-free white leghorn chickens. In trial 1, 14 chickens were inoculated intravenously with the virus at 21 days of age and euthanatized for necropsy within 1-14 days of inoculation. Gizzard erosion was grossly observed from day 7 postinoculation (PI), and histologically, FAV-99ZH antigen-positive, basophilic intranuclear inclusion bodies were seen in the gizzard lesions from day 7 to 11 PI. Necrotizing pancreatitis, and cholecystitis and cholangitis associated with the inclusions were observed from day 3 to 14 PI (pancreatitis) and from day 5 to 9 PI (cholecystitis and cholangitis), respectively. The inclusions were also observed in the epithelial cells of the cecal tonsils from day 3 to 5 PI. The virus was recovered from samples of the lesions. It was revealed that FAV-99ZH causes not only gizzard erosion but also pancreatitis, cholecystitis, and cholangitis by intravenous inoculation in chickens. In trial 2, 10 chickens were inoculated orally with the virus twice, at 13 and 36 days of age, and euthanatized for necropsy within 4-17 days after reinfection. Macroscopically, focal gizzard lesions were observed; however, neither necrosis nor inclusions were observed by microscopy. Moreover, FAV was not recovered from the gizzard or rectum of any of the chickens at necropsy. This suggests that the gizzard lesions occurred as a result of the primary infection, and that the chickens were able to resist reinfection.

Adenoviridae Infections↗
PubMed2004

Early pathophysiologic feature of arthropathy in juvenile dogs induced by ofloxacin, a quinolone antimicrobial agent.

Arthropathy in dogs induced by ofloxacin, a quinolone antimicrobial agent, was pathophysiologically investigated. In the in vivo studies, ofloxacin was administered orally once or twice at 20 mg/kg/day to male juvenile (3-month-old, n=3) or adult (36-month-old, n=2) dogs, and the humeral and femoral heads were examined pathologically. Unlike adult dogs, fluid-filled vesicles were macroscopically observed on the articular surfaces of one juvenile dog 24 hours after a single treatment with ofloxacin. These lesions were seen in all juvenile dogs by twice dosing. Microscopically, fissures or cavity formations in the middle zone of the articular cartilage were noted only in juvenile dogs. Furthermore, the cartilage matrix from the abnormal area to the articular surface showed a decreased safranin-O staining intensity, suggesting proteoglycan depletion. Ultrastructurally, chondrocytes in the middle zone of juvenile dogs displayed dilatation of the cisternae in the rough endoplasmic reticulum as an initial hallmark. In the in vitro studies, chondrocytes isolated from the articular cartilage of naive juvenile dogs were exposed to ofloxacin at 6.3-100 microg/ml for 24 hours. Although no changes were noted in the deoxyribonucleic acid synthesis, protein synthesis, or proteoglycan release at concentrations of up to 100 microg/ml, the proteoglycan synthesis was evidently decreased in a dose-dependent manner from 12.5 microg/ml. The results obtained suggest that the inhibitory action of ofloxacin on proteoglycan syntheses in the chondrocytes may largely contribute to the early morphologic features in the articular cartilage of the juvenile dog.

Age Factors↗
PubMed2004

[Surgical treatment for thoracoabdominal aortic aneurysm].

Spinal cord injury such as paraparesis and paraplegia remains one of the major concerns in surgery on the thoracoabdominal aortic aneurysm (TAAA). We utilize spinal cord protection including cerebrospinal fluid drainage (CSFD), adjuncts of aortic distal perfusion, reconstruction of the intercostal or lumbar arteries and deep hypothermia in TAAA repair. This report describes the results of surgical treatment for TAAA including postoperative neurological outcome. Between October 1999 and January 2004, 33 patients (mean age 66 years; range 26 to 81) underwent TAAA repair. Adamkiewicz artery could be detected using magnetic resonance angiography in 9 patients. CSFD was done in 20 patients. TAAA repair was achieved using adjuncts of aortic distal perfusion in 31 patients (partial cardiopulmonary bypass: 19, deep hypothermia: 9, left heart bypass: 3). We tried to reconstruct the intercostal or lumbar arteries which were located between Th8 and L2 as possible. Twenty-five patients underwent reconstruction of the intercostal or lumbar arteries. There were 6 hospital deaths. Postoperative spinal cord injury occurred in 4 patients (paraparesis: 1, paraplegia: 3). This clinical experience demonstrates that current technical strategies enable patients to undergo TAAA repair with acceptable early survival. However, despite aggressive spinal cord protection, few patients suffered from postoperative spinal cord injury. Future research should focus on spinal cord protection in patients with TAAA.

Adult↗
PubMed2003

Doppler effect in resonant photoemission from SF6: correlation between Doppler profile and Auger emission anisotropy.

Fragmentation of the SF6 molecule upon F 1s excitation has been studied by resonant photoemission. The F atomiclike Auger line exhibits the characteristic Doppler profile that depends on the direction of the photoelectron momentum relative to the polarization vector of the radiation as well as on the photon energy. The measured Doppler profiles are analyzed by the model simulation that takes account of the anisotropy of the Auger emission in the molecular frame. The Auger anisotropy extracted from the data decreases with an increase in the F-SF5 internuclear distance.

Journal Article↗
PubMed2003

Anisotropic ultrafast dissociation probed by the Doppler effect in resonant photoemission from CF4.

The resonant Auger spectrum from the decay of F 1s-excited CF4 is measured. Several lines exhibit a nondispersive kinetic energy as the exciting photon energy is tuned through the resonance region. The F 1s(-1) atomiclike Auger line is split into two components due to the emission of Auger electrons by a fragment in motion, when electron emission is observed along the polarization vector of the light. This Doppler splitting is direct evidence that the core excitation leads to T(d)-->C(3v) symmetry lowering, by elongation of a specific C-F bond preferentially aligned along the polarization vector of the incident photon.

Journal Article↗
PubMed2003

A prospective and randomized study of primary hormonal therapy for patients with localized or locally advanced prostate cancer unsuitable for radical prostatectomy: results of the 5-year follow-up.

OBJECTIVE: To evaluate the effect of primary hormonal therapy for patients with localized and locally advanced prostate cancer. PATIENTS AND METHODS: Patients with stage T1b-T3 prostate cancer who were not scheduled for radical prostatectomy were allocated into two groups: group 1 (73 men) received luteinizing hormone-releasing hormone (LHRH) agonist monotherapy and group 2 (78 men) received LHRH agonist and chlormadinone acetate. Patients were followed using serum prostate specific antigen levels, prostate size and the detection of distant metastasis for 5 years. RESULTS: The median (range) follow-up was 78 (63-87) months. The 5-year progression-free survival rate was significantly higher in group 2 (68%) than in group 1 (47%). However, the overall and cause-specific survival rate at 5 years were similar in both groups, at 72% and 93% in group 1, and 64% and 89% in group 2, respectively. CONCLUSION: The overall survival rates of the both groups were no different from that of the normal Japanese population of the same age group. Although this study did not include an untreated group, i.e. watchful waiting, these results might indicate the usefulness of primary hormonal therapy in controlling localized and locally advanced prostate cancer. The 5-year observation period is still short and the study is continuing to determine the 10-year survival.

Aged↗
PubMed2003

Alpha2-antiplasmin plays a significant role in acute pulmonary embolism.

The importance of pulmonary embolism (PE) due to venous thrombosis is recognized in the treatment of vascular diseases. We have investigated the physiological effects of plasmin generation in experimental acute PE using mice deficient in plasminogen (Plg-/-) or alpha2-antiplasmin (alpha2-AP-/-). PE was induced by continuous induction of venous thrombus in the left jugular vein by endothelial injury due to photochemical reaction. The mortality of wild-type mice was 68.8% at 2 h after the initiation of venous thrombosis and it was significantly reduced in alpha2-AP-/- mice (41.7%). In contrast, Plg-/- mice did not survive. Histological evidence of thromboembolism in the lung was obtained in all mice. However, whereas a strict thromboembolism was observed in Plg-/- mice, only a few thrombi were detected in the lungs of alpha2-AP-/- mice. Plasma fibrinogen levels measured in mice were not different. When alpha2-AP was infused in alpha2-AP-/- mice, the mortality was indistinguishable from wild-type mice. Tissue-type plasminogen activator (tPA) did not reduce the mortality due to acute PE in wild-type mice. However, in alpha2-AP-/- mice, tPA (0.52 mg x kg-1) significantly decreased the mortality compared with that of alpha2-AP-/- mice without tPA. The bleeding time was not significantly prolonged in either type of mice treated with tPA. The lack of plasminogen increases the mortality due to acute PE while a lack of alpha2-AP decreases the mortality rate, which can be further reduced by tPA administration. Therefore, the combination of inhibition of alpha2-AP with thrombolytic therapy could be beneficial in the treatment of acute PE.

Acute Disease↗
PubMed2003

Laparoscopic radical retropubic prostatectomy combined with approaches through a small open incision.

PURPOSE: The laparoscopic technique is now applied to radical prostatectomy. However, even in laparoscopic prostatectomy, we need a small open wound to remove the prostate from the abdomen. We have developed a modified technique of extraperitoneal laparoscopic radical prostatectomy, exploiting this small open wound as a route for surgical manipulations as well. Here, we described our technique and its initial outcomes. PATIENTS AND METHODS: An extraperitoneal retropubic space was developed with finger manipulations through a 3- to 5-cm long suprapubic incision. Three or four trocar ports were set up. A specially designed abdominal wall-lifter was applied to create an endoscopic working space. The surgeons worked using open or endoscopic manipulations through the suprapubic incision or the trocar ports. From October 2000 to August 2001, 11 patients with prostate cancer underwent this surgery. RESULTS: We completed surgery endoscopically without major complications except in one case in which we could not identify a bleeding source. Surgical time ranged from 229 to 469 min. Blood loss ranged from 550 to 3797 ml including urine spilled in the surgical field. Urinary continence returned in 10 cases at 1 to 8 months after surgery. One patient still needed pads at 3 months after surgery. CONCLUSION: Our technique allowed us to avoid insufflation of the abdomen with gas and intraperitoneal surgical intervention that are disadvantages of conventional laparoscopic prostatectomy, offering the same advantages as conventional laparoscopic prostatectomy.

Aged↗
PubMed2003

Experimental and clinical study of a holmium: YAG laser with adjustable pulse duration.

BACKGROUND: The holmium:YAG laser is used for treatment of urolithiasis, transurethral laser ablation for benign prostate hypertrophy and bladder tumor. The pulse duration was fixed in the previous Ho:YAG laser systems. We have evaluated more practical pulse durations to disintegrate the stone. The SPHINX Ho40 (Heraeus Corporation) can change the pulse duration freely in the range from 150 microsec. to 800 microsec. MATERIALS AND METHODS: 1) We measured the total energy to perforate through stone models at three different pulse durations (150, 300, 600 microsec.). 2) We experimented with the energy of each single pulse and the power of the shock wave. 3) We observed thermogenesis during the lithotripsy for each pulse duration. 4) Disintegration effects of Ho:YAG are compared with other lithotripsy systems in clinical cases. RESULTS: 1) It was possible that the smallest amount of the total energy went through the fragment at the pulse duration 150 microsec. 2) The maximum amount of energy of the wave is higher when the pulse duration is short. Although the amount of energy was 12.6 V, the amounts of energy at 800 microsec decreased with a pulse duration 150 microsec. to 6.46 V which was about 40 % 3) The highest temperatures achieved when the irradiation of laser was started and finished were compared. The shorter the pulse duration was, the higher was the peak power. The shock wave was also more effective to disintegrate stones on using short pulse durations. 4) The individual clinical success rates are Ho:YAG (85.1 %), Alexandrite (80.6 %) and Lithoclast (74.5 %).

Holmium↗