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Hitoshi Okamura

Publications and source records attributed to Hitoshi Okamura.

At least 55 records · Page 3Linked to original sources
PubMed2004

Psychologic distress after disclosure of genetic test results regarding hereditary nonpolyposis colorectal carcinoma.

BACKGROUND: To the authors' knowledge, there have been few studies of the psychologic distress after disclosure of genetic test results for hereditary nonpolyposis colorectal carcinoma (HNPCC). The objectives of this study were to identify the prevalence rates and predictors of psychologic distress and to evaluate the feelings of guilt after disclosure of the test results in Japanese probands and unaffected relatives. METHODS: Probands and unaffected relatives were interviewed immediately after the first genetic counseling session for HNPCC and again 1 month after disclosure of the genetic test results. The prevalence of major and minor depression, acute stress disorder (ASD), posttraumatic stress disorder (PTSD), and posttraumatic stress symptoms (PTSS) were assessed using the Structured Clinical Interview based on the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition revised (DSM-III-R) or the DSM-IV; feelings of guilt were investigated using a numeric scale and a semistructured interview. RESULTS: Among 47 participants who completed the baseline interview, 42 participants (89%) completed the 1-month follow-up interview. Although none of the participants met the criteria for major depression, ASD, or PTSD at the follow-up interview, 3 of 42 participants (7%) met the criteria for minor depression and 2 participants (5%) had PTSS. The only predictor of psychologic distress found was the presence of a history of major or minor depression (odds ratio, 19.41; 95% confidence interval, 1.42-264.95; P < 0.05). Five of 42 participants (12%) had feelings of guilt. CONCLUSIONS: Disclosure of genetic test results for HNPCC may not cause significant psychologic distress in Japanese probands or relatives. However, healthcare providers should not neglect to assess these individuals for psychologic responses, such as minor depression and PTSS.

Adult↗
PubMed2004

Decreased expression of 14-3-3 sigma is associated with advanced disease in human epithelial ovarian cancer: its correlation with aberrant DNA methylation.

PURPOSE: In this study, we examined the promoter methylation status and expression of 14-3-3 sigma and evaluated its clinical significance in epithelial ovarian cancer. EXPERIMENTAL DESIGN: Twelve ovarian cancer cell lines; 2 ovarian surface epithelial cell lines; and 8 normal, 8 benign, 12 borderline, and 102 ovarian cancer tissues were examined. Methylation-specific PCR, quantitative reverse transcription-PCR, and immunohistochemistry were used to evaluate methylation status and expression of 14-3-3 sigma gene and protein. RESULTS: Among the 12 ovarian cancer cell lines, the presence of a methylated band was detected in seven cell lines. Median values of relative 14-3-3 sigma gene expression in cancers with methylation (3.27) were significantly lower than those without methylation (16.4; P < 0.001). Treatment of 5-aza-2'-deoxycitidine resulted in the demethylation of the promoter CpG islands and reexpression. All of the normal, benign, and borderline tissues were positive for 14-3-3 sigma protein, and in ovarian cancer tissues, 73.5% (75 of 102) were positive for 14-3-3 sigma protein and was almost consistent with methylation status. Negative immunoreactivity of 14-3-3 sigma was significantly correlated with high age and serous histology, high-grade, advanced-stage residual tumor of >2 cm, high serum CA125, high Ki-67 labeling index, and positive p53 immunoreactivity. 14-3-3 sigma immunoreactivity was significantly associated with overall survival (P = 0.0058). CONCLUSIONS: Our findings suggest that 14-3-3 sigma is inactivated mainly by aberrant DNA methylation and that it may play an important role in the pathogenesis of epithelial ovarian cancer.

14-3-3 Proteins↗
PubMed2004

Expression of the angopoietin-1, angopoietin-2, Tie2, and vascular endothelial growth factor gene in epithelial ovarian cancer.

OBJECTIVES: Angiopoietin/Tie2 system with vascular endothelial growth factor (VEFG) is known to be important for the initiation of angiogenesis in tumors. The aim was to evaluate whether angiopoietin/Tie2 system with VEFG affects prognosis in patients of epithelial ovarian cancer. METHODS: Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2), Tie2, and VEGF gene expression were analyzed by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) in 85 epithelial ovarian cancer surgical specimens. These gene expressions were correlated with clinical-pathological parameters, microvessel density (MVD), and patients' survival. RESULTS: Ang-1/Ang-2 gene expression ratio, VEGF, and Tie2 gene expression significantly associated with MVD, respectively (P < 0.0001, P = 0.024, P = 0.005). The patients with low Ang-1/Ang-2 gene expression ratio and high VEGF gene expression were found to have a significantly higher MVD when compared to others (P = 0.0003). Moreover, there was a significant difference between the values of MVD in patients with low Ang-1/Ang-2 gene expression ratio and high VEGF and high Tie2 gene expression and those in others (P = 0.0025). FIGO stage (P = 0.014), residual disease (P = 0.042), histological grade (P = 0.028), Ang-1/Ang-2 gene expression ratio (P = 0.010), and combination of Ang-1/Ang-2 gene expression ratio and VEGF gene expression (P = 0.019), were found to be significantly associated with a poor prognosis in univariate Cox regression analysis. Multivariate Cox regression analysis revealed that FIGO stage is an independent prognostic factor (P = 0.035). Low Ang-1/Ang-2 gene expression ratio had a tendency to be an independent prognostic factor (P = 0.061). CONCLUSIONS: Angiogenesis occurred by angiopoietin/Tie2 system in concert with VEGF in epithelial ovarian cancer did not affect patients' survival. However, gene expression of Ang-1 and Ang-2 might present a pertinent diagnostic tool to select a high-risk group of patients independent of clinical-pathological parameters and a new insight to understand the biology of epithelial ovarian cancer.

Angiopoietin-1↗
PubMed2004

Clock genes in cell clocks: roles, actions, and mysteries.

Cellular events must be organized in the time dimension as well as in the space dimension for many proteins to perform their cellular functions effectively. The intracellular molecular oscillating loops that compose the cell's circadian clock coordinate the timing of the expression of a variety of genes with basic or specific cellular functions. In mammals, the temporal pattern of clock gene expression generated in each SCN neuron is coupled to those of other cells and, amplified, spreads its signals through the brain and then, via feeding behavior, glucocorticoids, and sympathetic nerves, to peripheral organs. These peripheral organs have their own circadian clocks. In some tissues, such as liver, there is also a clock-regulating cell cycle, which interacts strongly with the components and temporal organization of the circadian clock. Some tissues, however, such as testis, express clock genes whose function, if any, remains unclear. Furthermore, circadian clock function may be suspended in differentiating tissue. Thus, the prominence of circadian organization may not apply equally to all tissues under all conditions.

Animals↗
PubMed2004

Endometrial carcinoma in adenomyosis: assessment of myometrial invasion on T2-weighted spin-echo and gadolinium-enhanced T1-weighted images.

OBJECTIVE: The aim of our study was to compare T2-weighted and contrast-enhanced dynamic T1-weighted images with histologic findings in assessing the depth of myometrial invasion by endometrial carcinoma in adenomyosis. MATERIALS AND METHODS: We retrospectively reviewed the MRIs of 11 patients who had a total of 12 lesions of endometrial carcinoma within adenomyosis. T2-weighted and contrast-enhanced dynamic T1-weighted images were compared with the histologic findings separately. We assessed the extent of myometrial invasion by endometrial carcinomas. The depth of myometrial invasion seen on MRI was classified as stage S (superficial invasion), stage D (deep invasion), or undetectable. The staging accuracies of each sequence were assessed. The tumor-myometrium contrast-to-noise ratios were calculated for each sequence. RESULTS: The histologic specimens revealed that myometrial invasion was deep in seven of 12 lesions and superficial in five. On T2-weighted images the depth of invasion was underestimated in two lesions and impossible to determine in five lesions. On dynamic T1-weighted images the depth of invasion was overestimated in one lesion and underestimated in one lesion. The staging accuracy on dynamic T1-weighted images (83%) was significantly higher than that on T2-weighted images (42%). The contrast-to-noise ratio was significantly higher on dynamic T1-weighted studies during the early phase (mean +/- SD, 2.68 +/- 0.94) than it was on T2-weighted studies (1.74 +/- 1.05) and during the delayed phase (2.01 +/- 0.86). CONCLUSION: When adenomyosis coexists with endometrial cancer at the same site on T2-weighted images, contrast-enhanced dynamic T1-weighted imaging improves the accuracy of staging.

Adult↗
PubMed2004

Molecular signals of Mammalian circadian clock.

The circadian rhythm is originally generated by a transcription-translation based oscillatory loop composed of a set of clock genes in most organisms. The clock gene oscillation is generated by the core loop in each neuron of the hypothalamic suprachiasmatic nucleus. Phosphorylation and ubiquitination of clock proteins play the crucial role for the rhythmic transcription of clock genes. The core clock oscillation is conducted at the cellular levels by E-box or by D-box of clock controlled genes.

Animals↗
PubMed2003

Two types of VIP neuronal components in rat suprachiasmatic nucleus.

Vasoactive intestinal peptide (VIP) neurons constitute a large group in the suprachiasmatic nucleus (SCN) and it is thought that they are involved in the generation and entrainment of circadian rhythm. We have characterized these VIP-expressing neurons in rat SCN by their ability to induce the mammalian Period1 (Per1) gene in response to light exposure, innervation of retinal afferents, day-night variations in VIP mRNA, and coexpression of gastrin releasing peptide (GRP). VIP neurons in the ventrolateral SCN (SCNVL) were subdivided into two groups, light-evoked Per1-inducible main SCNVL (SCNVLmain) and non-Per1-inducible medially located SCNVL (SCNVLmed). Retinal innervation was abundant in the SCNVLmain but nearly absent in the SCNVLmed. Day-night variation in VIP mRNA expression level was observed in the SCNVLmain but not in the SCNVLmed. GRP mRNA was seen in rarely SCNVLmed but abundant in SCNVLmain, where some neurons coexpressed VIP mRNA. These findings indicate that VIP neurons in the SCN can be divided into two topographically and functionally distinct groups.

Animals↗
PubMed2003

Synchronization of cellular clocks in the suprachiasmatic nucleus.

Individual cellular clocks in the suprachiasmatic nucleus (SCN), the circadian center, are integrated into a stable and robust pacemaker with a period length of about 24 hours. We used real-time analysis of gene expression to show synchronized rhythms of clock gene transcription across hundreds of neurons within the mammalian SCN in organotypic slice culture. Differentially phased neuronal clocks are topographically arranged across the SCN. A protein synthesis inhibitor set all cell clocks to the same initial phase and, after withdrawal, intrinsic interactions among cell clocks reestablished the stable program of gene expression across the assemblage. Na+-dependent action potentials contributed to establishing cellular synchrony and maintaining spontaneous oscillation across the SCN.

ARNTL Transcription Factors↗
PubMed2003

Responses to noxious stimuli in mice lacking alpha(1d)-adrenergic receptors.

Nociceptive behaviors were examined in the mice lacking alpha1d-adrenergic receptor (alpha1d-AR) and wild type littermates using tail-flick, hot-plate (hindpaw-licking and jumping), tail-pinch and formalin tests. The distribution of alpha1d-AR was studied using in situ hybridization in the wild type mice. Mutant mice showed longer tail-flick and hindpaw-licking latencies while their jumping latency was shorter. Mechanical and chemical nociception was not altered in alpha1d-knockout mice. In situ hybridization study revealed dense alpha1d-AR mRNA expression in the reticular thalamic nucleus, the hippocampus, the cingulate cortex and the spinal cord. These results suggest that alpha1d-AR in the spinal cord contributes to thermal pronociception; and that the jump behavior seen when escaping from heat is inhibited via the supraspinal alpha1d-AR.

Animals↗
PubMed2003

Control mechanism of the circadian clock for timing of cell division in vivo.

Cell division in many mammalian tissues is associated with specific times of day, but just how the circadian clock controls this timing has not been clear. Here, we show in the regenerating liver (of mice) that the circadian clock controls the expression of cell cycle-related genes that in turn modulate the expression of active Cyclin B1-Cdc2 kinase, a key regulator of mitosis. Among these genes, expression of wee1 was directly regulated by the molecular components of the circadian clockwork. In contrast, the circadian clockwork oscillated independently of the cell cycle in single cells. Thus, the intracellular circadian clockwork can control the cell-division cycle directly and unidirectionally in proliferating cells.

ARNTL Transcription Factors↗
PubMed2003

Bimodal circadian secretion of melatonin from the pineal gland in a living CBA mouse.

Circadian melatonin secretion is the best-known output signal from the circadian pacemaker in the suprachiasmatic nucleus that indicates internal conditions of the body. We have established a system that enables long-term monitoring of melatonin secretion by implanting a transverse microdialysis probe in or near the pineal gland in a freely moving mouse. This in vivo method enabled continuous measurement of melatonin secretion over a period of >20 days in individual CBA mice, with simultaneous recording of the locomotor activity. Pineal melatonin secretion was completely matched to the circadian change of locomotor activity, and for the light-induced phase shift, the shift of melatonin secretion was clearer than the shift of locomotor rhythm. This analysis allowed us to detect rhythm with a high sensitivity: two peaks of daily secretion were observed, with the first small peak at the day-night transition time and the second large peak at midnight. The large nighttime peak was suppressed by tetrodotoxin, a Na+ channel blocker, and enhanced by both phenylephrine and isoproterenol, alpha- and beta-adrenergic agonists, whereas daytime melatonin levels were not affected by tetrodotoxin infusion. This finding suggests that, in CBA mice, melatonin release at night is activated by adrenergic signaling from the superior cervical ganglion, but the enhancement of melatonin during daytime is not mediated by neuronal signaling.

Animals↗
PubMed2003

Genetic and environmental contributions to severe preeclampsia: lack of association with the endothelial nitric oxide synthase Glu298Asp variant in a developing country.

OBJECTIVE: We recently identified a missense variant (Glu298Asp) within exon 7 of the endothelial nitric oxide synthase (eNOS) gene that is associated with severe preeclampsia in the Japanese population. Our objective was to analyze the association between the Glu298Asp eNOS gene variant and severe preeclampsia in a developing country where the incidence of preeclampsia is more frequent. METHODS: The study included 112 Bangladeshi women exhibiting severe preeclampsia and 119 control subjects. Screening for the Glu298Asp eNOS gene variant was carried out by analysis of the polymerase chain reaction-restriction fragment length polymorphism. RESULTS: The analysis revealed that the frequencies of the Glu298Asp variant (Glu298Asp homozygotes and heterozygotes) in the preeclampsia (n = 40; 35%) and control (n = 42; 35%) groups were not significantly (p > 0.05) different. CONCLUSIONS: We conclude that the presence of the Glu298Asp eNOS gene is not a marker for the increased risk of preeclampsia in a population where the level of prenatal care is such that preeclampsia is still frequently seen.

Adult↗
PubMed2003

Alterations of circadian expressions of clock genes in Dahl salt-sensitive rats fed a high-salt diet.

In mammals, behavioral and physiologic processes display 24-hour rhythms that are regulated by a circadian system consisting of central and peripheral oscillators. Because various cardiovascular functions show diurnal variations and abnormal patterns of circadian blood pressure variation carry a high risk of cardiovascular complications, we investigated whether the expression of clock genes is altered in an animal model of hypertension. In Dahl salt-sensitive rats fed a high-salt (4% NaCl) diet for 6 weeks (DS-H), radiotelemetry monitoring showed increased amplitude of circadian variations in blood pressure. The ratio of heart weight to body weight and the ratio of kidney weight to body weight were higher in DS-H. Echocardiographic data showed that the wall thickness of the left ventricle was greater in DS-H. Northern blot analysis and single cosinor analysis revealed that the amplitudes of circadian expression changes of the clock genes (mPer2, Bmal1, and dbp) in the heart, liver, and kidney were significantly decreased in DS-H rats compared with a normal-salt-diet group, except for Bmal1 in the liver. The circadian expression changes of plasminogen activator inhibitor-1, a clock-regulated gene, were attenuated in the hearts of DS-H. The present results demonstrate that DS-H show altered circadian expression of peripheral clock genes. Detailed analyses of the relation between circadian expression of clock genes and blood pressure regulation might reveal a role for chronologic therapy of cardiovascular disease.

ARNTL Transcription Factors↗
PubMed2003

Adrenergic regulation of clock gene expression in mouse liver.

A main oscillator in the suprachiasmatic nucleus (SCN) conveys circadian information to the peripheral clock systems for the regulation of fundamental physiological functions. Although polysynaptic autonomic neural pathways between the SCN and the liver were observed in rats, whether activation of the sympathetic nervous system entrains clock gene expression in the liver has yet to be understood. To assess sympathetic innervation from the SCN to liver tissue, we investigated whether injection of adrenaline/noradrenaline (epinephrine/norepinephrine) or sympathetic nerve stimulation could induce mPer gene expression in mouse liver. Acute administration of adrenaline or noradrenaline increased mPer1 but not mPer2 expression in the liver of mice in vivo and in hepatic slices in vitro. Electrical stimulation of the sympathetic nerves or adrenaline injection caused an elevation of bioluminescence in the liver area of transgenic mice carrying mPer1 promoter-luciferase. Under a light-dark cycle, destruction of the SCN flattened the daily rhythms of not only mPer1, mPer2, and mBmal1 genes but also noradrenaline content in the liver. Daily injection of adrenaline, administered at a fixed time for 6 days, recovered oscillations of mPer2 and mBmal1 gene expression in the liver of mice with SCN lesion on day 7. Sympathetic nerve denervation by 6-hydroxydopamine flattened the daily rhythm of mPer1 and mPer2 gene expression. Thus, on the basis of the present results, activation of the sympathetic nerves through noradrenaline and/or adrenaline release was a factor controlling the peripheral clock.

Animals↗
PubMed2003

Involvement of calcium/calmodulin-dependent protein kinase II in the induction of mPer1.

Recent studies suggest that CaM kinase II is involved in light-induced phase delays and induction of Per1 and Per2 genes in the hamster suprachiasmatic nucleus (SCN) (Yokota et al.,2001). We focused on intracellular mechanisms of the CaM kinase II-induced mPer1 gene expression. Immunoblotting and immunohistochemical analyses with isoform-specific antibodies against different isoforms of CaM kinase II and CaM kinase IV showed abundant expression of the delta isoform of CaM kinase II without significant expression of CaM kinase IV in the lateral ventral region of the rat SCN. We next defined the CaM kinase II-responsive region on the mPer1 promoter using a luciferase reporter gene assay. Transfection of the constitutively-active CaM kinase IIdelta greatly increased mPer1 promoter activity in NG108-15 cells and increased activity slightly but significantly in NB2A and C6 glioma cells. Similarly, transfection of a constitutively-active MEKK, an upstream kinase of mitogen-activated protein kinase (MAPK), greatly increased promoter activity in NB2A cells. Deletion and mutation analyses of the mPer1 promoter revealed that a 5'-GAGGGG-3' sequence motif near exon 1B, in which several zinc finger proteins seem to bind, was essential for the CaM kinase II-induced activation of the mPer1 promoter. These results suggest that CaM kinase IIdelta but not CaM kinase IV plays an essential role for mPer1 expression through the 5'-GAGGGG-3' motif on the mPer1 promoter.

Animals↗
PubMed2003

What we have learned from isolated cells from human ovary?

In the ovary, morphodynamics of follicles with cyclic maturation, ovulation and repair occur under the control of various tropic factors. The ovarian functions have been mostly studied by using subhuman primates and non-primate animals because of the limited availability of closely staged human specimens. We have recently established the in vitro culture systems of ovarian surface epithelium (OSE) and granulosa cells of humans, and subsequently developed the immortalization of each cell. The immortalized cell lines may supply us advanced studies on ovarian disorders as well as its physiological functions. On the embryologically putative müllerian potential of coelomic epithelium, endometriosis can be explained by coelomic metaplasia from the peritoneal mesothelium, including OSE. We can microscopically observe a continuity from flat epithelial cells on the ovarian surface or within the cortical inclusion cysts to endometriotic gland cells. The primary human OSE cells exhibited a glandular-stromal structure similar to endometriosis when they were co-cultured with endometrial stromal cells in an estrogen-rich environment. Primary and immortalized OSE cells converted the estrone to estradiol, and expressed the genes for steroidogenic factor-1 (SF-1), p450arom and 17beta-HSDs. This character of OSE was, in part, similar to the granulosa cells. One of the immortalized OSE clone produces disseminated tumors mimicking undifferentiated carcinomas in nude mice. Ovarian granulosa cells play a key role in the functional maturation of the entire follicle. The molecular pathways in granulosa cells responsible for the growth, differentiation, and nursing the oocyte are still largely unknown. Our immortalized human granulosa cell line, GC1a, obtained from developing follicles, showed no steroid hormone biosynthesis, and no detectable expression of the genes for StAR or cytochrome p450 enzymes due to the lack of SF-1. Transfected SF-1 elicited estradiol secretion in GC1a cells with concomitant expression of the genes encoding the proteins for gonadal steroidogenesis. The enzymatic activity of 17beta-HSD was also achieved by SF-1 transgene. These results indicate that SF-1 controls the gene expression required for steroidogenesis in the human developing follicle. Clinically, immortalized GC1a cells from human origin, with steroidogenic capacity, may serve as a feeder layer for in vitro oocyte maturation. Further investigations of our immortalized OSE and granulosa cells of humans will allow us to clarify whether they have a single progenitor cell.

Animals↗
PubMed2003

Ovarian hyperstimulation syndrome-model rats; the manifestation and clinical implication.

Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of ovulation induction with the gonadotropins. Though vascular endothelial growth factor (VEGF) has been implicated as a prime causative factor of OHSS progression, other factors must also be involved in the pathogenesis of OHSS. We have established an experimental model of OHSS in immature female rats. The ovarian weights and vascular permeability of the OHSS model rats are significantly increased by the ovarian stimulation with human chorionic gonadotropin (hCG). hCG elicits VEGF production in OHSS model rat ovaries. The addition of potent synthetic progesterone antagonist RU486, which reduces the extension of OHSS, attenuates the ovarian kinin and VEGF production dose-dependently whereas the VEGF gene expression was stable. VEGF protein detected in both the lung and the liver of the OHSS model rats is not affected at 24 h after the addition of hCG and RU486 in contrast to the ovary. Our results demonstrate that progesterone is implicated in the development of OHSS, in part, to enhance the ovarian VEGF production by post-transcriptional and organ-specific control.

Animals↗