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Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Evaluation of value of coronary artery bypass grafting without cardiopulmonary bypass for emergency or subemergency case].

From August 1999 through September 2000, emergency (operation within 24 hours after hospitalization) or subemergency (within 48 hours) coronary artery bypass grafting without cardiopulmonary bypass (OPCAB) was performed in 16 patients (EM group) with a mean age 71.9 years old (range: 47-85). The patients were divided into 3 groups of which were acute myocardial infarction (AMI) group, chronic heart failure (CHF) group and unstable angina (u-AP) group, and compared preoperative hemodynamics, the number of graft, target arteries, bypass patency and hospitalization period after surgery with 26 patients performed the elective OPCAB in the same duration (EL group). All patients in EM group were used intra-aortic balloon pumping (IABP) assist before operation. In EL group, 16 patients (61.5%) were required IABP (p < 0.05). Ejection fraction and cardiac index in CHF group were significantly lower than those of EL group (47.8 +/- 1.1 vs. 63.3 +/- 2.4, 2.8 +/- 0.2 vs. 1.9 +/- 0.2: p < 0.05). Pulmonary capillary wedge pressure in AMI group and CHF group was significantly higher than that of EL group (16.7 +/- 5.9, 20.8 +/- 5.4 vs. 7.2 +/- 0.8: p < 0.01). There was a significant difference in the mean number of bypass in EM group compared with that of EL group (1.8 +/- 0.2 vs. 2.7 +/- 0.2: p < 0.05). In AMI group and CHF group, the grafting rate to the major vessel in the anterior wall was occupied in more than 70% of all bypasses per patient, however that was less than 50% in EL group. The arterial graft was actively used for revascularization. The hospitalization period in AMI group and CHF group was longer than that in u-AP group and EL group (28.5 +/- 9.8, 38.8 +/- 7.4 vs. 15.7 +/- 1.5, 13.0 +/- 0.7: p < 0.01). There was no difference in bypass patency between EM group and EL group (96.6 vs. 97.2). During the follow-up period, any death and complications were not recognized in both groups. These results suggested that OPCAB would be one of the valuable procedures in the emergent coronary artery bypass grafting.

Adult↗
PubMed2001

P-type ATPase diversity and evolution: the origins of ouabain sensitivity and subunit assembly.

Molecular aspects of the diversity of P-type ATPases are explored in this review. From the substrate specificities among different ATPase molecules, the existence of isoforms within a single class of pump becomes evident and it is now recognized as a universal phenomenon. From the phylogenetic analyses using a vast collection of the deduced amino acid sequences for the P-type ATPase subunits, it also becomes evident that the divergence of substrate-specificity occurred early in the evolution and has been conserved ever since. Further extensive analyses identify a set of novel isoforms that retain an ancestral characteristic of the Na+/K+-(H+/K+-)ATPases in invertebrates.

Amino Acid Sequence↗
PubMed2001

Finite element simulation of piezoelectric transformers.

Piezoelectric transformers are nothing but ultrasonic resonators with two pairs of electrodes provided on the surface of a piezoelectric substrate in which electrical energy is carried in the mechanical form. The input and output electrodes are arranged to provide the impedance transformation, which results in the voltage transformation. As they are operated at a resonance, the electrical equivalent circuit approach has traditionally been developed in a rather empirical way and has been used for analysis and design. The present paper deals with the analysis of the piezoelectric transformers based on the three-dimensional finite element modelling. The PIEZO3D code that we have developed is modified to include the external loading conditions. The finite element approach is now available for a wide variety of the electrical boundary conditions. The equivalent circuit of lumped parameters can also be derived from the finite element method (FEM) solution if required. The simulation of the present transformers is made for the low intensity operation and compared with the experimental results. Demonstration is made for basic Rosen-type transformers in which the longitudinal mode of a plate plays an important role; in which the equivalent circuit of lumped constants has been used. However, there are many modes of vibration associated with the plate, the effect of which cannot always be ignored. In the experiment, the double resonances are sometimes observed in the vicinity of the operating frequency. The simulation demonstrates that this is due to the coupling of the longitudinal mode with the flexural mode. Thus, the simulation provides an invaluable guideline to the transformer design.

Journal Article↗
PubMed2001

[A case report of the dissecting aneurysm of ascending aorta, which was surmised to be developed after aortic valve replacement].

Bentall operation was performed for the ascending aortic dissection in the patient of a 70-year old man, who had undergone aortic valve replacement (AVR) for aortic valve regurgitation 7 years ago. At the AVR, the diameter of the ascending aorta was 50 mm on CT. During the follow up period after AVR, the ascending aorta was gradually developed to 95 mm in diameter without any symptoms. During the reoperation, entry was recognized on the prior aortotomy reinforced with felt-strips and the intimal flap was thickened. These situations suggested that the aortic dissection might be occurred just or early after AVR, and the reinforcement of aortotomy using felt-strips and AVR could not prevent progression of aortic root enlargement and dissection. From some previous reports about ascending aortic dissection after AVR, an adequate surgical treatment for a dilated ascending aorta (40-50 min) should be required at the same time of AVR.

Aged↗
PubMed2001

Detailed morphology of human ovarian surface epithelium focusing on its metaplastic and neoplastic capability.

Ovarian epithelial tumors are thought to derive from the surface epithelium of the ovary, which differentiates after invagination of the coelomic mesothelium over the gonadal ridges during early embryonic development. On the putative mullerian potential of this epithelium, endometriosis, including ovarian endometriosis, can be explained by a metaplastic process from the peritoneum. In the present study, we assessed specific changes in the architecture and in the cytological characteristics of human ovarian epithelial cells on the surface and within the inclusion cyst. Grossly normal ovaries were retrieved from 215 patients undergoing incidental oophorectomy and 33 patients with contralateral ovarian tumor. In addition, 75 patients diagnosed with epithelial ovarian cancer and 26 ovarian endometriosis patients undergoing oophorectomy were selected. The incidence of cortical invagination, epithelial papillomatosis and pseudostratification was not different in normal ovaries between pre- and post-menopausal women, whereas inclusion cysts were more frequently observed in post-menopausal women (p<0.05). The occurrence rates of invagination and inclusion cysts were significantly higher in normal ovaries examined after incidental oophorectomy (p<0.05) and in those with contralateral ovarian tumor (p<0.05), respectively. Although serous metaplastic change with cilia was most common and it did not differ before and after menopause, the frequency of mucinous, endometrioid and transitional cell changes was low in the two groups of pre- and post-menopausal women. Mucinous metaplasia was more frequently observed in patients with contralateral ovarian tumor than those without ovarian tumor (12.1% vs. 1.9%; p<0.05). Four (5.3%) of 75 ovarian cancer patients revealed malignant transformed cells from a single layer of normal epithelium covering the ovarian surface or inclusion cyst. Ovarian or extraovarian endometriosis was identified in 16 (21.3%) of 75 epithelial ovarian cancer patients analyzed. An in situ carcinogenesis in the endometriotic cyst was seen in three epithelial ovarian cancers (4.0%). In seven (26.9%) of 26 ovarian endometriosis cases, epithelial cells on the ovarian surface or within the inclusion cyst were histologically changed to endometriotic gland cells. Careful and extensive observations of surgical specimens with ovarian carcinoma and ovarian endometriosis showed that they originated from the ovarian epithelium lining the surface and cortical small cysts.

Endometriosis↗
PubMed2001

[Combined off-pump CABG (OPCAB) and abdominal vascular surgery].

Two simultaneous operations for off-pump CABG (OPCAB) and abdominal vascular surgery were performed safely and effectively. [Case 1] A 52-year-old man was admitted with the right intermittent claudication and angina pectoris. Coronary angiography and aortography showed 90% stenosis of left anterior descending coronary artery (LAD) and the right external iliac artery. The patient underwent 1 CABG using left internal thoracic artery (ITA) without cardiopulmonary bypass and abdominal aorta--the right external iliac bypass simultaneously. Bleeding volume during the operation was only 150 ml. The operation time was 3 hours 50 minutes. [Case 2] A 57-year-old man was referred from the other hospital with complaints of abdominal aortic aneurysm. He had the history of 4 stroke attacks caused by idiopathic aldosteronism. Preoperative coronary angiography and aortography showed severe 3 vessels disease and abdominal aortic aneurysm. First, we harvested bilateral ITAs, the right gastroepiploic artery (GEA) and saphenous vein (SV). The complete revascularization (left ITA-LAD, right ITA-1st diagonal branch, GEA-seg. 4 posterodescending branch, SV graft-posterolateral branch) was performed on the beating heart. Then we repaired the abdominal aortic aneurysm (56 mm in diameter) using a Gelsealed Y-graft. The operative course was uneventful. The operation time was 6 hours 15 minutes. These cases suggested that OPCAB technique combined with abdominal vascular surgery reduced operation time and prevented complication in the patient with the risk of brain trouble.

Angina Pectoris↗
PubMed2000

Phase-dependent responses of Per1 and Per2 genes to a light-stimulus in the suprachiasmatic nucleus of the rat.

Single brief and discrete light treatments are sufficient to reset the overt mammalian rhythms of nocturnal rodents. In the present study, we examined the phase-dependent response of the mammalian clock genes, Per1 and Per2, to a brief strong light-stimulus (1000 lux) in the circadian oscillator center, the suprachiasmatic nucleus (SCN) of rats. Light-induced elevation of Per1 mRNA was observed through the subjective night (CT16, CT20 and CT0 (=CT24)) with a marked peak at the subjective dawn (CT0). However, the light influence was very limited for the induction of Per2; only weak elevation of Per2 mRNA was detected at CT16. The effect of light-stimulus on the Per1 gene was transient, and the effect was restricted to ventrolateral SCN neurons in both CT0 and CT16 after light exposure. Since it is known that these rats show a light-induced behavioral phase-shift throughout the subjective night with being strongest at subjective dawn, the present results suggest that the transient induction of Per1 in ventrolateral SCN neurons is a critical step in the resetting of the biological clock to environmental light-dark schedule.

Animals↗
PubMed2000

Defective T cell function for inhibition of growth of Mycobacterium avium-intracellulare complex (MAC) in patients with MAC disease: restoration by cytokines.

To define the immunopathologic mechanism underlying pulmonary Mycobacterium avium-intracellulare complex (MAC) disease in patients without AIDS, the ability of CD4(+) and gammadelta T cells to induce growth inhibition of MAC in monocytes was compared between patients and healthy control subjects. T cell-dependent growth inhibition and production of interferon-gamma and macrophage colony-stimulating factor decreased in patients. CD4(+) T and gammadelta T cells from patients were equally defective in inducing anti-MAC activity. The combination of these cytokines restored the ability of patients' T cells to control MAC growth. In experiments with allogeneic cocultures of gammadelta T cells and infected monocytes from patients and control subjects, healthy control T cells could augment growth inhibition of MAC in monocytes from patients, whereas patients' T cells could not, even in the presence of healthy control monocytes. These results indicate that the defect in T cells may be associated with impaired protective immunity against MAC in these patients.

Aged↗
PubMed2000

N-methyl-D-aspartate receptor subtype 2C is not involved in circadian oscillation or photoic entrainment of the biological clock in mice.

Ishida et al. [1994: Neurosci Lett 166: 211-215] reported the circadian change of N-methyl-D-aspartate (NMDA) receptor subtype 2C mRNA and photic induction of this receptor's mRNA in the suprachiasmatic nucleus (SCN). Therefore, we investigated the role of NMDA receptor subtypes in the biological clock using NMDA receptor 2A (NR2A)- or 2C (NR2C)-deficient mice. However, NR2C-/- mice showed normal light-dark (LD)-entrained locomotor activity rhythms and free-running rhythms under constant darkness and also exhibited normal reentrainment to 6-hr LD shifts and phase delays with single light pulses. Thus, present results demonstrated no significant NR2C contribution to circadian oscillation and photic entrainment, even though expression of NR2C mRNA was highly observed in the SCN. On the other hand, the period of the free-running activity rhythm in NR2A-/- mice but not NR2C-/- mice was slightly longer than that in wild-type mice in spite of low expression of NR2A in the SCN. Furthermore, reentrainment to an LD advance in NR2A-/- mice was slower under low-intensity light conditions. Thus, we suggest that NR2A plays a role in determining the behavioral state that affects the circadian rhythm. In order to elucidate the role of NR2A and NR2C in the SCN, we examined NMDA-induced Ca(2+) elevations in the SCN of mutant mice using a Ca(2+) imaging method. A partial reduction in Ca(2+) elevation was observed in both NR2A-/- and NR2C-/- mice when high concentrations (100 or 300 microM) of NMDA were applied. The present results suggest that NR2A plays a weak role in oscillation or entrainment of the biological clock, and that NR2C does not participate in the functions of circadian oscillation and light entrainment.

Animals↗
PubMed2000

A psychosocial group intervention for Japanese women with primary breast carcinoma.

BACKGROUND: To the authors' knowledge, there had been no evidence for the efficacy of psychosocial intervention among Japanese cancer patients. The objective of this study was to determine the effect of a psychosocial group intervention in reducing psychologic distress and enhancing coping in this population in a randomized controlled trial. METHODS: The patient selection criteria were age younger than 65 years, lymph node metastasis positive and/or histologic or nuclear Grade 2-3, and surgery undergone within the previous 4-18 months as of the start of the study. We conducted a 6-week, structured, psychosocial group intervention. The intervention consisted of health education, coping skills training, stress management, and psychologic support. Subjects were assessed for psychologic distress and coping by administering the Profile of Mood States (POMS), Mental Adjustment to Cancer (MAC) scale, and Hospital Anxiety and Depression (HADS) scale at the baseline, at 6 weeks, and at 6 months. RESULTS: Fifty (33%) of the 151 patients participated and were randomized, and 46 (30%) completed the study. The experimental group had significantly lower scores than the controls for total mood disturbance and significantly higher scores for vigor on the POMS, and significantly higher scores for fighting spirit on the MAC at the end of the 6-week intervention. These improvements were sustained over 6 months of follow-up. CONCLUSIONS: The results of this study suggest that a short term psychosocial group intervention produces significant long term improvement in the quality of life of Japanese patients with primary breast carcinoma.

Adaptation, Psychological↗
PubMed2000

Depression after successful treatment for nonsmall cell lung carcinoma.

BACKGROUND: There have been few studies of depression in nonsmall cell lung carcinoma (NSCLC) patients after successful treatment. The purpose of the study was to clarify the prevalence and the correlated factors of depression after surgery. METHODS: A structured interview was conducted for patient characteristics and social support with NSCLC patients at baseline. One-month prevalence of depression at 1 and 3 months after surgery was obtained by follow-up interviews at 1 and 3 months after surgery, respectively, whereas that of depression at 2 months after surgery was by the latter interview retrospectively. Three-month prevalence of depression was determined as presence of depression during any month in of a period of 3 months after surgery. A logistic analysis was used to examine the correlated factors of depression during the 3 months after surgery. RESULTS: Of 223 consecutive cancer patients who participated in the study between June 1996 and April 1999, 33 (14.8%) met the criteria for major or minor depression during the 3 months after surgery. One-month prevalence of depression at 1, 2, and 3 months after surgery were 9.0%, 9.4%, and 5.8%, respectively. The results of logistic regression analysis revealed that only satisfaction with confidants before surgery, of patient characteristics and social support factors, was significantly associated with depression during the 3 months after surgery. CONCLUSIONS: These results suggest that depression is not rare after successful treatment for NSCLC and that social support may play an important role for NSCLC patients with depression after successful treatment.

Adult↗
PubMed2000

Rapid generation of potent and tumor-specific cytotoxic T lymphocytes by interleukin 18 using dendritic cells and natural killer cells.

We hypothesized that antitumor-specific immunity, which is induced by interleukin (IL) 18 treatment in murine tumor models, is promoted by enhancing natural killer (NK)-mediated destruction of tumor and delivery to dendritic cells (DCs). These activated and antigen-pulsed DCs then critically and optimally induce an adoptive immune response, positioning IL-18 as an important bridge between the innate and adoptive immune response. The effect of IL-18 added to cultures of live tumor cells (MCA205, a mouse sarcoma cell line), NK cells, DCs, and T cells was assessed. When recombinant (r) mIL-18 protein was added to this culture, potent NK cytolytic activity with subsequent generation of CTLs was observed in a dose-dependent manner. Without introduction of either rmIL-18 or NK cells into this culture, systemic cytolytic activity was significantly decreased. Following the absence of direct contact of either NK cells or DCs with other cells in this cooperative coculture system using transwell, the systemic cytolytic activity of both NK cells and CTLs was greatly suppressed. The cytolysis mediated by effector cells harvested after completion of the culture was primarily restricted to MHC class I and highly specific for the tumor cells used in the coculture. Furthermore, we examined the efficiency in the induction of cytolytic T cells of other established IFN-gamma inducing T-cell growth factors, IL-2, and IL-12 in this culture system and compared them with that mediated by IL-18. Neither IL-2 nor IL-12 induced tumor-specific cytolytic T cells to the same degree as that mediated by IL-18. Efficacy of this system in induction of tumor-specific CTLs was also observed in the system using MC38 adenocarcinoma cells. These results are consistent with the notion that IL-18 induces tumor-specific immunity through enhancing NK activity, which in turn mediates tumor cell death and activates and primes DCs.

Adenocarcinoma↗
PubMed2000

Nonphotic entrainment by 5-HT1A/7 receptor agonists accompanied by reduced Per1 and Per2 mRNA levels in the suprachiasmatic nuclei.

In mammals, the environmental light/dark cycle strongly synchronizes the circadian clock within the suprachiasmatic nuclei (SCN) to 24 hr. It is well known that not only photic but also nonphotic stimuli can entrain the SCN clock. Actually, many studies have shown that a daytime injection of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH DPAT), a serotonin 1A/7 receptor agonist, as a nonphotic stimulus induces phase advances in hamster behavioral circadian rhythms in vivo, as well as the neuron activity rhythm of the SCN in vitro. Recent reports suggest that mammalian homologs of the Drosophila clock gene, Period (Per), are involved in photic entrainment. Therefore, we examined whether phase advances elicited by 8-OH DPAT were associated with a change of Period mRNA levels in the SCN. In this experiment, we cloned partial cDNAs encoding hamster Per1, Per2, and Per3 and observed both circadian oscillation and the light responsiveness of Period. Furthermore, we found that the inhibitory effect of 8-OH DPAT on hamster Per1 and Per2 mRNA levels in the SCN occurred only during the hamster's mid-subjective day, but not during the early subjective day or subjective night. The present findings demonstrate that the acute and circadian time-dependent reduction of Per1 and/or Per2 mRNA in the hamster SCN by 8-OH DPAT is strongly correlated with the phase resetting in response to 8-OH DPAT.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2000

Skin-specific caspase-1-transgenic mice show cutaneous apoptosis and pre-endotoxin shock condition with a high serum level of IL-18.

To study the pathophysiological roles of overexpressed caspase-1 (CASP1), originally designated as IL-1 beta-converting enzyme, we generated transgenic mice in which human CASP1 is overexpressed in their keratinocytes. The transgenic mice spontaneously developed recalcitrant dermatitis and skin ulcers, characterized by the presence of massive keratinocyte apoptosis. The skin of the mice contained the active form of human CASP1 and expressed mRNA for caspase-activated DNase, an effector endonuclease responsible for DNA fragmentation. Their skin and sera showed elevated levels of mature IL-18 and IL-1 beta, but not of IFN-gamma. The plasma from these animals induced IFN-gamma production by IL-18-responsive NK cells. Administration of heat-killed Propionibacterium acnes, a potent in vivo type 1 cell inducer, caused IFN-gamma-mediated lethal liver injury in the transgenic mice, which was completely inhibited by treatment with neutralizing anti-IL-18 Ab. These results indicated that in vivo overexpression of CASP1 caused spontaneous apoptotic tissue injury and rendered mice highly susceptible to exogenous type 1 cell-inducing condition in collaboration with endogenously accumulated proinflammatory cytokines.

Animals↗
PubMed2000

The 5' upstream region of mPer1 gene contains two promoters and is responsible for circadian oscillation.

The mPer1 gene is assumed to be a key molecule in the regulation and functioning of the mammalian circadian clock, which is based on the oscillation generated by a transcription-(post)translation feedback loop of a set of clock genes [1]. Robust circadian oscillation and acute light-elicited induction of mPer1 mRNA expression have been observed in the suprachiasmatic nucleus (SCN), the mammalian circadian center [2] [3]. To investigate the mechanism underlying the complex regulation of mPer1 expression, we isolated and characterized the 5' upstream region of the mPer1 gene. Unexpectedly, we identified two promoters, each followed by alternative first exons of mPer1. Consistent with the presence of multiple E-boxes in the promoters, exon-specific in situ hybridization of the SCN established that both promoters function in circadian oscillation and in light-induction of mPer1 expression. Transgenic mice carrying the 5' upstream region of the mPer1 gene fused to the luciferase gene demonstrated that a DNA fragment carrying both promoter regions is sufficient to elicit striking circadian oscillation in the SCN and responsiveness to light. Moreover, luminescence in the SCN accurately mirrored the mPer1 transcriptional activity. These transgenic mice will be very useful for monitoring clock-specific mPer1 expression in intact organisms and to follow the circadian clock in real time.

Animals↗
PubMed2000

Prevalence, predictive factors, and screening for psychologic distress in patients with newly diagnosed head and neck cancer.

BACKGROUND: High levels of distress are a concern regarding patients with head and neck cancer. Early detection of and intervention for such distress are needed to predict patients' adaptation to treatment or rehabilitation, but few studies have investigated the detection of their distress in a patient population of significant size. METHODS: The authors examined 107 consecutive patients with head and neck cancer to assess their psychologic distress (adjustment disorders or major depression) or other psychiatric problems by structured psychiatric interview before the initial cancer treatment. They also evaluated predictive factors for psychologic distress and assessed the ability of a self-rating questionnaire (Hospital Anxiety and Depression Scale, HADS) to screen for distress. RESULTS: Of 107 subjects, 18 (16.8%) had an adjustment disorder or major depression. Thirty-six (33.6%), 7 (6. 5%), and 35 (32.7%) met criteria for alcohol dependence, alcohol abuse, and nicotine dependence, respectively. Logistic regression analysis revealed that having advanced stage cancer (odds ratio, 5. 77; 95% confidence interval [CI], 1.41-39.7; P = 0.03) and living alone (odds ratio, 4.83; 95% CI, 1.04-22.2; P = 0.04) were significantly associated with having psychologic distress. The optimal cutoff point for the HADS screening for psychologic distress was 15. This cutoff point gave 72.2% sensitivity and 81.4% specificity. CONCLUSIONS: Head and neck cancer patients who have advanced disease or live alone should be assessed so that psychologic distress can be detected and intervention made. HADS is a useful clinical instrument to screen for their distress.

Adjustment Disorders↗
PubMed2000

Precise measurement of dp elastic scattering at 270 MeV and three-nucleon force effects

The cross section, the deuteron vector A(d)(y) and tensor analyzing powers A(ij), the polarization transfer coefficients K(y('))(ij), and the induced polarization P(y(')) were measured for the dp elastic scattering at 270 MeV. The cross section and A(d)(y) are well reproduced by Faddeev calculations with modern data-equivalent nucleon-nucleon forces plus the Tucson-Melbourne three-nucleon force. In contrast, A(ij), K(y('))(ij), or P(y(')) are not described by such calculations. These facts indicate the deficiencies in the spin dependence of the Tucson-Melbourne force and call for extended three-nucleon force models.

Journal Article↗