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Biomedical subjects

N Nishikawa

Publications and source records attributed to N Nishikawa.

At least 19 recordsLinked to original sources

Epigenetic inactivation of TCF2 in ovarian cancer and various cancer cell lines.

Transcription factor 2 gene (TCF2) encodes hepatocyte nuclear factor 1beta (HNF1beta), a transcription factor associated with development and metabolism. Mutation of TCF2 has been observed in renal cell cancer, and by screening aberrantly methylated genes, we have now identified TCF2 as a target for epigenetic inactivation in ovarian cancer. TCF2 was methylated in 53% of ovarian cancer cell lines and 26% of primary ovarian cancers, resulting in loss of the gene's expression. TCF2 expression was restored by treating cells with a methyltransferase inhibitor, 5-aza-2'deoxycitidine (5-aza-dC). In addition, chromatin immunoprecipitation showed deacetylation of histone H3 in methylated cells and, when combined with 5-aza-dC, the histone deacetylase inhibitor trichostatin A synergistically induced TCF2 expression. Epigenetic inactivation of TCF2 was also seen in colorectal, gastric and pancreatic cell lines, suggesting general involvement of epigenetic inactivation of TCF2 in tumorigenesis. Restoration of TCF2 expression induced expression of HNF4alpha, a transcriptional target of HNF1beta, indicating that epigenetic silencing of TCF2 leads to alteration of the hepatocyte nuclear factor network in tumours. These results suggest that TCF2 is involved in the development of ovarian cancers and may represent a useful target for their detection and treatment.

Base Sequence↗

Determination of vitamin B12 using the enzyme glycerol dehydrase.

Glycerol dehydrase is an enzyme that catalyzes dehydration of glycerol into beta-propionaldehyde. It requires 5'-deoxyadenosylcobalamin, one of the forms of vitamin B12, as a coenzyme. The enzyme is inactivated in vitro by all forms of vitamin B12 stoichiometrically. The objective of this study was to determine vitamin B12 content by utilizing the inactivation of the enzyme by vitamin B12. After various examinations, an excellent standard curve was obtained up to 1 pmol vitamin B12 using 14 mU of the enzyme per tube. Glycerol dehydrase does not respond to vitamin B12 if it is bound to haptocorrin, a vitamin B12-binding protein. This necessitates a procedure for extraction of vitamin B12 from samples before assay. The enzyme was less inactivated by 5'-deoxyadenosylcobalamin than any other form of vitamin B12. However, this did not matter because all forms of vitamin B12 were converted into cyanocobalamin during the extraction procedure cited above, which was performed in a buffer containing potassium cyanide.

Aldehydes↗

Cyclooxygenase-2 is a possible target of treatment approach in conjunction with photodynamic therapy for various disorders in skin and oral cavity.

BACKGROUND: Anti-cancer effects of cyclooxygenase (COX)-2 inhibitors have been reported, but not fully investigated in skin and oral diseases. 5-aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) for treating those patients with skin and oral lesions is a highly sophisticated procedure, but the incidence of disease recurrence after treatment is rather significant. OBJECTIVE: To confirm that COX-2 could be a molecular target in adjunctive therapy to ALA-based PDT, we investigated (i) COX-2 expression in various skin and oral diseases, and (ii) the inhibitory effects on cellular growth of COX-2 selective inhibitor (nimesulide), ALA-based PDT and their combination on human oral squamous cell carcinoma (SCC) cell lines. METHODS: A total of 129 biopsy samples from the skin and oral mucosal lesions were tested immunohistochemically for COX-2 expression. Then the in vitro effects of nimesulide, ALA-based PDT, and their combination were determined on two SCC cell lines, HSC-2 and HSC-4. Three different methods (MTT assay, double-staining for annexin V and propidium iodide, caspase-3/CPP32 fluorometric protease assay) were applied for evaluation of their inhibitory effects on these two cell lines. RESULTS: Among the skin diseases, a considerable number of COX-2 high expressers were found in actinic keratosis (15 of 25, 60%), Bowen's disease (13 of 17, 76%) and extramammary Paget's disease (15 of 15, 100%). In contrast, only one of 33 (3%) basal cell carcinoma tumours was a COX-2 high expresser. Among the oral mucosal biopsies, the proportion of COX-2 high expressers increased gradually from hyperplasia (one of six, 17%) through mild dysplasia (five of eight, 63%) and moderate dysplasia (20 of 23, 87%) to severe dysplasia (two of two, 100%). Nimesulide had an inhibitory effect in vitro on HSC-2 (proven to be a COX-2 high expresser), but not on HSC-4 (a COX-2 non-expresser). While ALA-based PDT showed an inhibitory effect on both HSC-2 and HSC-4, most importantly the combination of nimesulide and ALA-based PDT demonstrated a significant synergistic effect on the cellular growth inhibition of only HSC-2, but not of HSC-4. CONCLUSIONS: Our study strongly suggests that COX-2 can be one of the molecular targets in treating various skin and oral diseases. The results from our in vitro experiments also prompt us to develop a new protocol with a combination of COX-2 selective inhibitor and ALA-based PDT for more effective treatment of those diseases.

Aminolevulinic Acid↗

Long-term administration of amlodipine prevents decompensation to diastolic heart failure in hypertensive rats.

UNLABELLED: OBJECTIVES; We assessed the effects of long-term amlodipine administration in a diastolic heart failure (DHF) rat model with preserved systolic function as well as the relationship between changes in left ventricular (LV) myocardial stiffening and alterations in extracellular matrix. BACKGROUND: Although the effect of long-term administration of amlodipine has been shown to be disappointing in patients with systolic failure, the effect is unknown in those with DHF. METHODS: Dahl salt-sensitive rats fed a high-salt diet for seven weeks were divided into three groups: eight untreated rats (DHF group), eight rats given high-dose amlodipine (10 mg/kg/day; HDA group) and seven rats given low-dose amlodipine (1 mg/kg/day; LDA group). RESULTS: High-dose administration of amlodipine decreased systolic blood pressure and controlled excessive hypertrophy, without a decrease in the collagen content, and prevented the elevation of LV end-diastolic pressure at 19 weeks. Low-dose administration of amlodipine with subdeppressive effects did not control either hypertrophy or fibrosis; however, it prevented myocardial stiffening and, hence, the elevation of LV end-diastolic pressure. The ratio of type I to type III collagen messenger ribonucleic acid levels was significantly lower in both the HDA and LDA groups than in the DHF group. CONCLUSIONS: Long-term administration of amlodipine prevented the transition to DHF both at the depressor and subdepressor doses. Amlodipine did not decrease the collagen content, but attenuated myocardial stiffness, with inhibition of the phenotype shift from type III to type I collagen. Thus, amlodipine may exert beneficial effects through amelioration of collagen remodeling in the treatment of DHF.

Amlodipine↗

Multicolour spectral karyotyping for complex chromosomal rearrangements in repeated abortion or congenital anomalies.

Advances in molecular cytogenetics, especially the technique of fluorescence in situ hybridization (FISH), have allowed more precise definition of chromosomal structures, which are difficult to identify using conventional G-banding. Recently, a novel approach based on hybridization of 24 fluorescent-labelled chromosome painting probes was developed, termed spectral karyotyping (SKY), which allows the simultaneous and differential colour display of all human chromosomes. We have used SKY to identify not only five parental complex translocation carriers but also minute chromosome rearrangements in the fetus. Here, we concentrate attention on the clinical application of SKY for prenatal diagnosis.

Abortion, Habitual↗

Surgical results of skull base surgery for the treatment of head and neck malignancies involving skull base: multi-institutional studies on 143 cases in Japan.

We analyzed 143 cases of skull base surgery collected from the eight institutions of the Study Group supported by the Grant-in-Aid for Cancer Research from the Ministry of Health and Welfare of Japan. Histologically, the most common type was squamous cell carcinoma (n = 78), which was followed by olfactory neuroblastoma (n = 16) and adenoid cystic carcinoma (n = 16). The most frequent surgical approach was frontal craniotomy (n = 66), followed by front-temporal craniotomy (n = 54) and infratemporal fossa approach (n = 8). For repair of dura matter, fascia lata was used in 37 cases. galeopericranial flap in 35 and temporal muscle fascia in 16. The 5-year survival rate by Kaplan-Meier method of nose and paranasal sinus carcinoma (n = 119) was 48%. As for histological classification, the survival rates were both 65%) in adenoid cystic carcinoma (n = 12) and bone soft tissue malignancy (n = 10), 62% in olfactory neuroblastoma (n = 16), 46% in squamous cell carcinoma (n = 62) and 33% in adenocarcinoma (n = 11). All the three cases of malignant melanoma died within 1 year, so we considered skull base surgery to be contraindicated for this disease. Complications were observed in 62 out of the 143 cases (43%); local infection was most frequent in 29 cases. liquorrhea in 18, abscess in 16, necrosis of the flap and meningitis in ten cases, DIC in four, rupture of the internal carotid artery in two and cerebral thrombosis in one. Death caused directly by surgery was in ten cases (7%). It is important that a multi-center registry be maintained to have a large enough database for comparison of results, and prognosis for each histological entity and further define the role of multidisciplinary treatment.

Adult↗

A case of successful fetal therapy for congenital chylothorax by intrapleural injection of OK-432.

A 38-year-old multiparous woman was referred at 19 weeks' gestation because of hydrops fetalis. Ultrasonic examination revealed severe pleural effusion, ascites and skin edema. Detailed examination of the amniotic fluid, fetal blood and intrathoracic fluid led to a diagnosis of congenital fetal chylothorax. Repeated thoracocenteses were not effective in improving the hydrops fetalis. We introduced fetal treatment for the pleural effusion by an intrapleural injection of OK-432 at 23, 24 and 25 weeks' gestation. The pleural effusion was reduced by adhesion of the intrathoracic space and resulted in the delivery of a neonate who was healthy except for right renal dysfunction. Pulmonary hypoplasia was successfully prevented by OK-432.

Adult↗

E2F regulates growth-dependent transcription of genes encoding both catalytic and regulatory subunits of mouse primase.

DNA polymerase alpha-primase is one of the principal enzymes involved in eukaryotic chromosomal DNA replication. Mouse DNA polymerase alpha-primase consists of four subunits with molecular masses of 180, 68, 54 and 46 kDa. Protein and mRNA expression levels of the four subunits are up-regulated in a coordinated manner in response to growth stimulation. We have previously analysed the transcription of the 180 kDa (p180) and 68 kDa (p68) subunits, which form the DNA polymerase catalytic complex, and found that growth-dependent regulation of transcription of the mouse p180 and p68 genes is mediated by a common factor, E2F, while the basal transcription of the genes is regulated by different transcription factors. We characterized the transcriptional regulation of the 54 kDa (p54) and 46 kDa (p46) subunits, which form the DNA primase catalytic complex. We isolated genomic clones spanning the 5'-flanking regions of the p54 and p46 genes and showed, using transient expression and gel mobility shift assays, that the basal transcription of p54 is controlled by Sp1 and GA-binding protein, as is the basal transcription of the p180 gene. The basal transcription of p46 is controlled by unknown factor(s) which were bound to the upstream sequence. The variant E2F sites close to the transcription initiation sites of the p54 and p46 genes had no basal promoter activity, but were essential for the growth-dependent transcription of both genes. The promoter regions of the four subunits of mouse DNA polymerase d-primase complex share several common features. The coordinated transcription of all four subunits in response to growth stimulation appears to be controlled by E2F.

3T3 Cells↗

Ventricular production of natriuretic peptides and ventricular structural remodeling in hypertensive heart failure.

OBJECTIVES: Brain natriuretic peptide (BNP) is a strong predictor of left ventricular (LV) hypertrophy (LVH) and dysfunction. However, our recent studies suggested that LVH is not necessarily associated with enhanced production of BNP in hypertension. This study aimed to clarify the relation of the characteristics of hypertrophy with the degree of gene expression of BNP in the developmental process of hypertensive heart failure. METHODS: Serial changes in LV geometry, histology and atrial natriuretic peptide (ANP) and BNP mRNA levels, were assessed in a hypertensive heart failure model using Dahl salt-sensitive rats (n = 24). We further studied effects of alpha1-receptor antagonist (doxazosin: 1 mg/kg per day, n = 5) and angiotensin II type 1 receptor (AT1R) antagonist (candesartan cilexetil: 1 mg/kg per day, n = 5). RESULTS: The BNP mRNA level was not elevated at the compensatory hypertrophic stage when ANP mRNA level was elevated. BNP mRNA level was increased with further progression of hypertrophy and development of fibrosis. AT1R blockade prevented such fibrosis and further progression of hypertrophy with normalization of BNP mRNA levels. Compensatory hypertrophy was not suppressed; therefore, ANP mRNA level, although decreased, was still beyond the normal level. The alpha1-receptor blockade slightly attenuated LV hypertrophy with a slight decrease in ANP mRNA levels. LV fibrosis was not prevented, and the BNP mRNA level was not decreased. CONCLUSIONS: BNP gene expression is not enhanced by initial compensatory hypertrophy, but is enhanced by LV fibrosis and late stage progression of hypertrophy dependent on AT1R-mediated signaling pathway.

Animals↗

Effect of carotid endarterectomy on chronic ocular ischemic syndrome due to internal carotid artery stenosis.

OBJECTIVE: We evaluated the effect of carotid endarterectomy on chronic ocular ischemic syndrome due to internal carotid artery stenosis by use of data obtained from ophthalmic artery color Doppler flow imaging. METHODS: We examined 11 patients with ocular ischemic syndrome due to internal carotid artery stenosis (>70% stenosis) who were being treated by carotid endarterectomy. Ophthalmic artery color Doppler flow imaging indicated ophthalmic artery flow direction and peak systolic flow velocity and was performed before and at 1 week, 1 month, and 3 months after surgery. RESULTS: We assessed the ophthalmic arteries of 11 patients via color Doppler flow imaging. Before undergoing carotid endarterectomy, five patients showed reversed ophthalmic artery flow. In the other six patients who experienced antegrade ophthalmic artery flow, the average peak systolic flow velocity was 0.09 +/- 0.05 m/s (mean +/- standard deviation). Preoperative reversed flow resolved in each patient 1 week after undergoing surgery. All patients showed antegrade ophthalmic artery flow. The average peak systolic flow velocity in the patients who had preoperative antegrade flow rose significantly, to 0.21 +/- 0.14 m/s (P < 0.05). There was no significant change as compared with findings at 1 week after surgery. During the follow-up period (mean, 32.4 mo), no patients complained of recurrent visual symptoms. At the end of the study period, visual acuity had improved in five patients and had not worsened in the other six patients. CONCLUSION: Carotid endarterectomy was effective for improving or preventing the progress of chronic ocular ischemia caused by internal carotid artery stenosis.

Angiography↗

[A case of suspected pulmonary air embolism in endoscopic neurosurgery].

Sudden reduction in end-tidal PCO2 and SpO2 occurred during the endoscopic third ventriculostomy in a patient with hydrocephalus under general anesthesia. We suspect that it was caused by pulmonary air embolism. A 63-year-old female was scheduled for endoscopic third ventriculostomy under general anesthesia. Endoscopic manipulation caused hemorrhage from chorioid plexus 21 minutes after the procedure was begun, and intraventricular irrigation was performed to achieve hemostasis. In the subsequent 3 minutes, end-tidal PCO2 declined from 26 mmHg to 15 mmHg (PaCO2 39.6 mmHg), and SpO2 declined from 98% to 92% (PaO2 69.2 mmHg). Nitrous oxide was discontinued immediately because pulmonary air embolism was suspected and the oxygen concentration was increased to 100%. At the same time the surgical procedure was discontinued. After 15 minutes, end-tidal PCO2 recovered to 25 mmHg, and SpO2 recovered to 98% (PaO2 136.5 mmHg), and surgery was resumed. The patient recovered from anesthesia. The chest X-p at the end of operation, and pulmonary scintigraphy on the following day revealed no abnormal findings, but brain CT demonstrated a large quantity of air in both lateral ventricles.

Embolism, Air↗

Calcineurin inhibitor attenuates left ventricular hypertrophy, leading to prevention of heart failure in hypertensive rats.

BACKGROUND: There is controversy regarding the contribution of calcineurin activation to the development of pressure-overload left ventricular (LV) hypertrophy and heart failure. The aim of this study was to explore whether the inhibition of calcineurin may prevent the transition to heart failure in hypertensive rats and, if so, to clarify in which developmental stage of LV hypertrophy calcineurin plays a key role. METHODS AND RESULTS: Dahl salt-sensitive rats placed on an 8% NaCl diet from the age of 7 weeks (hypertensive rats) were randomized to no treatment (n=6) or treatment with the calcineurin inhibitor FK506 (1 mg x kg(-1) x d(-1)) from 8 weeks (FKE, n=7) or from 17 weeks (FKL, n=7). Rats placed on a 0.3% NaCl diet were defined as control rats (n=6). The administration of FK506 from 8 weeks attenuated, although it did not block, LV hypertrophy observed in the untreated rats and prevented the transition to heart failure. The development of LV fibrosis, however, was not attenuated by the administration of FK506 from 8 weeks. The administration of FK506 from 17 weeks brought no benefit for cardiac remodeling or LV function and failed to prevent heart failure. CONCLUSIONS: Calcineurin inhibition, if started from the initial stage of pressure overload, attenuated the development of LV hypertrophy without any effect on LV fibrosis and prevented the transition to heart failure. The activation of calcineurin is involved in the development of LV hypertrophy but not of LV fibrosis, and this involvement may be crucial at the initial stage.

Animals↗

Use of echocardiography for predicting myocardial viability in patients with reperfused anterior wall myocardial infarction.

Dobutamine stress echocardiography (DSE), myocardial contrast echocardiography (MCE), and ultrasonic tissue characterization with integrated backscatter are useful methods for assessing myocardial viability in acute myocardial infarction. In this study, we compared the potential of 3 methods for predicting myocardial viability in 38 patients with reperfused anterior wall acute myocardial infarction. We performed MCE shortly after coronary reperfusion with an intracoronary injection of microbubbles. We recorded 2-dimensional integrated backscatter images at rest and, then, performed low-dose (10 microg/kg/min) DSE 3 days later. In integrated backscatter images, we placed the region of interest in the midwall of the myocardial segment to reconstruct the cyclic variation of myocardial integrated backscatter. The myocardial segment was judged viable when it showed active contraction 3 months later. Among 74 segments analyzed, 34 were judged viable. Presence of contractile response during DSE predicted segmental viability with 91% sensitivity and 78% specificity. Intense and homogenous contrast enhancement with MCE predicted viability with 82% sensitivity and 73% specificity. The presence of synchronous contraction of cyclic variation predicted myocardial viability with 79% sensitivity and 83% specificity. There were no differences in sensitivity and specificity among the 3 methods. Thus, MCE and ultrasonic tissue characterization can predict myocardial viability as accurately as DSE in patients with acute myocardial infarction. The logistics of the methods may determine clinical application.

Angioplasty, Balloon, Coronary↗

Roles of renin-angiotensin and endothelin systems in development of diastolic heart failure in hypertensive hearts.

OBJECTIVE: Although interest in diastolic heart failure is growing because of its clinical frequency, little is known about this type of heart failure. Our laboratory recently developed a diastolic heart failure model using Dahl salt-sensitive rat. In this model, gene expression of angiotensin-converting enzyme and endothelin (ET) system in the left ventricle was enhanced at heart failure stage without downregulation of angiotensin type 1a receptor mRNA level. However, the roles of these humoral systems in the transition to diastolic failure remain unclear. METHODS: Subdepressor doses of angiotensin II type 1 (AT1) receptor and ET type A (ETA) receptor antagonists were administered in this model just after onset of hypertension, and their effects were investigated. RESULTS: Neither AT1 nor ETA receptor blockade inhibited the early (13 weeks) compensatory left ventricular (LV) hypertrophy. This form of compensatory hypertrophy is associated with subnormal LV end-systolic stress, which was normalized by AT1 receptor blockade but not by ETA receptor blockade. Progression of LV hypertrophy and fibrosis and transition to heart failure (19 weeks) in the untreated rats were prevented by both antagonists, resulting in normalization of LV end-diastolic pressure and lung weight. AT1 receptor blockade, but not ETA receptor blockade, normalized time constant of LV relaxation. Enhanced gene expression for ET system in the left ventricle observed in the untreated rats was suppressed with AT1 receptor antagonist administration. ETA receptor blockade slightly but significantly elevated the AT1a receptor mRNA level as compared with the untreated rats. CONCLUSIONS: RAS and ET system contribute to the transition to diastolic heart failure through the development of excessive hypertrophy and ventricular fibrosis in hypertensive heart diseases, however, neither RAS nor ET system is mandatory for normal compensation for pressure overload. RAS apparently causes such diastolic effects at least partly through the ET system.

Angiotensin Receptor Antagonists↗

Use of the abdominal wall fat index determined ultrasonographically for assessing the risk of post-operative pulmonary embolism.

OBJECTIVE: To assess the usefulness of the abdominal wall fat index (AFI) for predicting pulmonary embolism (PE) after gynecologic surgery. METHOD: The subjects were 115 female patients who underwent laparotomy for gynecologic disease. They were divided into low-dose heparin therapy (n=28) and control, without heparin (n=87) groups. The AFI ratio of the maximum preperitoneal fat thickness to the minimum subcutaneous fat thickness was determined using ultrasonography. RESULT: Post-operative PE occurred in four control patients. If the cut-off value of the AFI for predicting PE development was set at more than or equal to 0.85, the sensitivity was 1.00 and the specificity was 0.60 (P=0.03). If we restricted the criteria, and set the cut-off value of the AFI to more than or equal to 0.85 in patients with hypertension [systolic blood pressure (BP)>/=140 mmHg, diastolic BP>/=90 mmHg or patients were taking antihypertensive medication], the sensitivity and specificity were 0. 75 and 0.92, respectively (P=0.001). CONCLUSION: Visceral fat obesity is a risk factor for PE after gynecologic surgery, and the AFI is useful for predicting PE and for whom post-operative low-dose heparin therapy may be indicated.

Abdomen↗

Evolving changes in Doppler mitral flow velocity pattern in rats with hypertensive hypertrophy.

OBJECTIVES: The aim of our study was to explore evolving changes in a mitral flow velocity pattern (MFVP) and its hemodynamic and pathological correlates in hypertensive rats in an isolated diastolic heart failure model. BACKGROUND: Development of left ventricular (LV) hypertrophy and concomitant diastolic dysfunction cause heart failure in hypertensive hearts even with normal systolic function; however, associated evolving change in MFVP is still unclear. METHODS: Mitral flow velocity pattern was recorded every 2 weeks from 7 to 19 weeks in six hypertensive rats. Hemodynamic and pathological correlates of Doppler mitral flow indexes were examined as an additional part of the study using the hypertensive rats at the age of 13 weeks (compensatory stage, n = 7) and at 19 weeks (heart failure stage, n = 8). RESULTS: Initial development of pressure overload LV hypertrophy resulted in a decrease in early diastolic filling wave (E), a reciprocal increase in the filling wave due to atrial contraction (A) and prolongation of deceleration time of E wave (relaxation abnormality pattern). These changes were associated with an increase in tau, an index of LV relaxation, but without a change in LV end-diastolic pressure. Transition to congestive heart failure caused an increase in E, a decrease in A and shortening of deceleration time. These changes were not associated with further increase in tau but with elevation of LV end-diastolic pressure, reflecting marked LV hypertrophy and myocardial fibrosis. CONCLUSIONS: Development of pressure overload LV hypertrophy is associated with evolving changes in MFVP from normal to relaxation abnormality pattern and, in turn, to pseudonormalized to restrictive pattern. Analysis of MFVP may be useful to follow not only functional but also constitutional changes of the myocardium in hypertensive hearts.

Animals↗

Sex chromosomal analysis of spermatozoa from infertile men using fluorescence in situ hybridization.

PURPOSE: To confirm an association between male infertility and chromosome aberrations of spermatozoa, we demonstrated the frequency of numerical abnormalities of spermatozoa from infertile men with abnormal semen parameters compared with fertile controls. METHOD: Sperm cells from 10 infertile patients were investigated for disomy rates of sex chromosomes and chromosome 18 and diploidy by fluorescence in situ hybridization (FISH). All patients showed oligoasthenozoospermia with sperm counts 3-20 x 10(6)/ml and motile rates 0-40%. RESULTS: Regarding XY disomy, a significantly higher frequency was found in 8 of 10 patients as compared to normal fertile men. The disomy rates of chromosome 18, XX, YY, and diploidy rate were not increased. CONCLUSIONS: There is an association between male infertility and embryo with aneuploidy of sex chromosomes. Counseling about possible genetic risks should be provided to the infertile couples planning assisted reproduction treatment.

Aneuploidy↗