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Biomedical subjects

E Aoki

Publications and source records attributed to E Aoki.

At least 19 recordsLinked to original sources
PubMed2003

Distribution of OL-protocadherin protein in correlation with specific neural compartments and local circuits in the postnatal mouse brain.

OL-protocadherin (OL-pc) is a cell adhesion molecule that belongs to the cadherin superfamily. A previous study showed that expression of OL-pc mRNA was specific to certain brain nuclei including those of the olfactory and limbic systems, thus suggesting its involvement in neural circuit formation. Here, we examined the distribution of OL-pc protein in the postnatal mouse brain by immunohistochemistry to confirm the possibility of such a role. The results showed that the protein could be mapped to many brain compartments including brain nuclei and higher subdivisions as previously observed for the expression pattern of the mRNA. Sharp boundaries of the distribution were often seen in areas such as the interpedunclar nucleus, cerebellar cortex, and inferior olive. In addition, the protein was detected in some fibers that could not be examined by the previous study using in situ hybridization. For example, prominent staining was noted in the stria medularis, stria terminalis, fasciculus retroflexus, optic tract, and inferior thalamic radiation, structures that seem to connect OL-pc-positive brain regions. These OL-pc-positive brain nuclei and fiber tracts coincide with some local circuits of functional systems such as the olfactory system, nigrostriatal projection, olivo-cerebellar projection, and visual system. These results support the possibility that OL-pc is involved in the formation of specific neural compartments and circuits in the developing brain.

Aging↗
PubMed2001

Effects of sugar on vegetative development and floral transition in Arabidopsis.

Although sugar has been suggested to promote floral transition in many plant species, growth on high concentrations (5% [w/v]) of sucrose (Suc) significantly delayed flowering time, causing an increase in the number of leaves at the time of flowering in Arabidopsis. The effect of high concentrations of Suc seemed to be metabolic rather than osmotic. The delay of floral transition was due to extension of the late vegetative phase, which resulted in a delayed activation of LFY expression. In addition, growth on low concentrations (1% [w/v]) of Suc slightly inhibited flowering in wild-type plants. This delay resulted from effects on the early vegetative phase. This inhibition was more pronounced in tfl1, an early flowering mutant, than in the wild type. Although 1% (w/v) Suc was reported to promote floral transition of late-flowering mutants such as co, fca, and gi, floral transition in these mutants was delayed by a further increase in Suc concentration. These results suggest that sugar may affect floral transition by activating or inhibiting genes that act to control floral transition, depending on the concentration of sugars, the genetic background of the plants, and when the sugar is introduced. Growth on 1% (w/v) Suc did not restore the reduced expression levels of FT and SOC1/AGL20 in co or fca mutants. Rather, expression of FT and SOC1/AGL20 was repressed by 1% (w/v) Suc in wild-type background. The possible effects of sugar on gene expression to promote floral transition are discussed.

Anthocyanins↗
PubMed2000

Citrulline immunohistochemistry for demonstration of NOS activity in vivo and in vitro.

Nitric oxide (NO), a biomolecule with major cytotoxic potency, is generated by NO synthases (NOS) utilizing l-arginine as substrate and citrulline is formed as a "side product." In brain tissue, citrulline is considered to be produced exclusively by NOS, due to the incomplete urea cycle in the brain. We aimed to characterize NOS activity by citrulline immunostaining in different cell types of the brain under in situ conditions and in slice and culture experiments. NOS-positive neurons and activated microglial cells were the most prominent citrulline-positive structures. Lack of citrulline immunoreaction in neurons of nNOS knockout mice emphasizes the dependency of citrulline positivity on NOS activity, and likewise there was no citrulline staining after application of the NOS inhibitors 7-nitroindazole and NIL. Interestingly, only a portion of NOS-containing neurons costained for citrulline. The inhibition of argininosuccinate synthetase by alpha-methyl-dl-aspartate increased the number of citrulline-positive cells, apparently due to reduction of the turnover rate of citrulline. Cells positive for NOS but negative for citrulline may indicate that the enzyme is either not activated or inhibited by cellular control mechanisms. The fact that not all citrulline-positive cells were NOS positive may be explained by an insufficient detection sensitivity or by disparate sites of citrulline production and recycling. The present results show that citrulline immunocytochemistry offers a viable and convenient means for studying NOS activity at the single-cell level to elicit its posttranslational control under physiological and pathophysiological conditions.

Animals↗
PubMed2000

Clonality analysis by methylation-specific PCR for the human androgen-receptor gene (HUMARA-MSP).

The human androgen-receptor gene (HUMARA) has been used for analysis of X chromosome inactivation (XCI) pattern because of a polymorphic short tandem repeat (STR) near the 5'-promoter region correlated with XCI. We introduce a novel method to analyze XCI pattern, named HUMARA methylation-specific PCR (HUMARA-MSP) assay, which analyzes methylation status of the HUMARA gene by bisulfite modification instead of a methylation-sensitive restriction enzyme. Although the original MSP method shows whether there is a methylated band or not, our HUMARA-MSP method identifies the patterns of methylated and unmethylated bands. Because this method identifies either unmethylated or methylated alleles in each PCR tube and shows opposite band patterns dependent on methylation status, we can assess the XCI pattern independently twice. This method can avoid false results by incomplete enzyme digestion and incomplete bisulfite modification will not affect the results. Extremely small quantities of samples, such as hematopoietic colonies, were also available for HUMARA-MSP assay. Because DNA modified by sodium bisulfite is also available for assessment of methylation status of other genes by setting specific primers for them, we performed the simultaneous assessment of clonality and aberrant hypermethylation of p15INK4B gene in myelodysplastic syndromes. These simultaneous assessments were easily possible and provided much information despite requiring only a small volume of DNA. The HUMARA-MSP assay may facilitate the analyses for pathogenesis of hematological disorders because of its simplicity, sensitivity and wide applicability. Leukemia (2000) 14, 207-212.

Base Sequence↗
PubMed2000

Methylation status of the p15INK4B gene in hematopoietic progenitors and peripheral blood cells in myelodysplastic syndromes.

We previously reported that the hypermethylation of the p15INK4B gene promoter was frequently observed in myelodysplastic syndromes (MDS), and that it may be associated with disease progression. An unanswered question is whether p15INK4B gene methylation is restricted to undifferentiated blastic cells, or whether differentiated cells such as granulocytes or erythrocytes of MDS origin also harbor this epigenetic alteration. In this study, we analyzed the methylation status of the p15INK4B gene in MDS by the methylation-specific PCR (MSP) method, which is more sensitive than Southern blotting. The bone marrow mononuclear cells (BM-MNCs) of 23 MDS patients were analyzed, and six of them showed p15INK4B methylation. Progenitor assay with methylcellulose medium was also performed in all patients. In two of the six patients with p15INK4B-methylated BM-MNCs, erythroid and/or non-erythroid colonies formed were subjected to molecular analysis. Colonies with and without p15INK4B methylation were detected in both patients. Furthermore, X-chromosome inactivation (XCI) pattern of each colony was simultaneously determined by MSP-based human androgen receptor gene analysis (HUMARA-MSP), and all p15INK4B-methylated colonies showed the same XCI pattern, which was dominant among the colonies, while p15INK4B-unmethylated colonies showed both patterns of XCI, in each of the two patients. We then examined the methylation status of the p15INK4B gene of granulocyte (PB-PMN) fractions from 10 patients with available peripheral blood cells. In all four patients with p15INK4B-methylated BM-MNCs, their PB-PMNs showed p15INK4B methylation. These results suggest that p15INK4B methylation in hematopoietic cells in MDS patients is restricted to the MDS clone but not necessarily to blast cells.

Acute Disease↗
PubMed1999

DNA replication in the 1-cell mouse embryo: stimulatory effect of histone acetylation.

Temporal and spatial distribution of the sites of DNA replication were examined in 1-cell mouse embryos. Embryos were labelled with bromodeoxyuridine (BrdU) at hourly intervals after fertilisation, and the incorporation of BrdU was examined by laser-scanning confocal microscopy following immunostaining with an anti-BrdU antibody. DNA replication first started uniformly in both the male and female pronuclei in the intranuclear region and then was observed in the peripheral regions of nucleus and nucleolus. These changes, however, occurred asynchronously in that the female pronucleus required a longer time to complete replication in the intranuclear region but not in the peripheral regions. Inhibiting transcription with alpha-amanitin had no effect on the temporal and spatial patterns of DNA replication. Treatment of the embryos with trapoxin, a specific inhibitor of histone deacetylase, accelerated the completion of replication in the peripheral regions but not in the intranuclear region. These results suggest that DNA replication is temporally and spatially regulated in the 1-cell embryos and that acetylation of histones, but not transcription, is involved in the regulation of DNA replication.

Acetylation↗
PubMed1998

Isolation and identification of metallothionein isoforms (MT-1 and MT-2) in the rat testis.

It has been a long-lasting controversial issue as to whether or not the male genital organs, such as the testis and prostate, contain metallothioneins (MTs), a group of cysteine-rich heavy-metal-binding proteins that play a role in detoxifying heavy metals such as cadmium (Cd). Earlier studies reported that the rodent testis lacks MTs and concluded that this is why the testis is very susceptible to Cd, although other indirect experimental evidence suggests that MTs are present in this organ. A deficiency of MTs in the testis was originally suspected on the basis of amino acid composition analysis, since MT-like proteins isolated as Cd-binding proteins did not have a characteristic MT structure. In the present study, we demonstrate that the rat testis indeed expresses Cd-binding proteins with sequences identical to those previously described for MT-1 and MT-2, the major isoforms. To confirm that MT-1 and MT-2 are present in the rat testis, we purified and isolated Cd-binding proteins by homogenization using Cd-containing buffer, followed by sequential purification using Sephadex G-75 gel filtration chromatography and anion HPLC column chromatography, which yielded Cd-binding protein-1 (Cd-BP-1) and -2 (Cd-BP-2). After pyridylethylation, Cd-BP-1 and Cd-BP-2 were subjected to specific protein fragmentation by acids and endopeptidases, which revealed that these Cd-binding proteins have the same primary structures as MT-1 and MT-2 respectively. Thus we believe that the present results clearly resolve the long-standing debate about the presence of MTs in the testis, at least in the rodent.

Amino Acid Sequence↗
PubMed1997

Closure of a ventricular septal defect in a patient with von Willebrand disease.

Few reports of open heart surgery being performed in patients with von Willebrand disease (vWD) have been documented. We describe herein the case of a 5-year-old girl with a ventricular septal defect (VSD) and vWD who underwent patch closure under cardiopulmonary bypass (CPB). The hematological parameters relating to vWD, namely, factor VIII, von Willebrand factor, and factor VIII-related antigen were monitored perioperatively. These laboratory findings were elevated after the termination of CPB, and consistently maintained within the normal range for 4 months postoperatively. The operation was successfully completed without the administration of factor VIII concentrates or homologous blood products.

Cardiopulmonary Bypass↗
PubMed1997

Immunohistochemical localization of arginine and citrulline in rat renal tissue.

Using antibodies highly specific for L-arginine and L-citrulline, we localized these amino acids in rat kidney with immunohistochemical methods. Highest levels of arginine immunoreactivity were observed in epithelial cells of proximal tubules in the outer stripe of the outer medulla and the collecting ducts in the cortex. Staining intensity of proximal convoluted tubules in the outer stripe decreased from the inner side to the outer side. In the inner medulla, collecting ducts were labeled with moderate intensity. Staining within the cortex was apparent only with collecting ducts. Citrulline immunoreactivity was localized in the epithelial cells of collecting ducts both in the cortex and medulla. Immunoreactivity was also found in glomerular podocytes and in the epithelial cells of proximal convoluted tubules in the outer medulla. These localizations were different from those of other amino acids previously reported. The precise cellular distribution of arginine and citrulline in rat kidney was determined for the first time by an immunohistochemical method in the present study.

Animals↗
PubMed1997

Septal perfusion and wall thickening in patients with left bundle branch block assessed by technetium-99m-sestamibi gated tomography.

UNLABELLED: Septal hypoperfusion is often observed in patients with complete left bundle branch block (LBBB) in myocardial perfusion imaging. Abnormal wall motion in the septal region may potentially cause artifactual perfusion abnormalities. To assess the effect of abnormal wall thickening on myocardial perfusion images, ECG-gated sestamibi SPECT was performed on 12 patients with LBBB and 10 normal subjects used as controls. METHODS: After administration of 740 MBq 99mTc-sestamibi injection at rest, ECG-gated SPECT was obtained 60 min later with division of the cardiac cycle into eight frames. RESULTS: Septal hypoperfusion was noted in 10 patients on nongated images and 11 patients on end-systolic (ES) images, whereas only two patients showed abnormalities on end-diastolic (ED) images. The septal to lateral wall count ratio in the LBBB group was lower (0.72 +/- 0.09) than in the control group (0.84 +/- 0.09) (p < 0.01) at nongated images, while it was similar at ED images (0.84 +/- 0.11 versus 0.86 +/- 0.12; ns). In addition, the count increase from ED to ES during a cardiac cycle in the septal region was smaller compared with the lateral region in the LBBB patients (25% +/- 19% in the septal region, versus 48% +/- 14% in the lateral region; p < 0.01), indicating less wall thickening in the septal region. CONCLUSION: Smaller count increase due to reduced wall thickening in the septal region may mimic hypoperfusion in patients with LBBB. This artifact can be eliminated with ECG-gated 99mTc-sestamibi SPECT, particularly with ED images.

Aged↗
PubMed1997

[Ascending aortic aneurysms operated through redo median sternotomy under selective cerebral perfusion].

Case 1: A 34-year-old man who had received ventricular septal closure at 4 years old was found to suffer from annuloaortic ectasia with severe aortic regurgitation and giant ascending aortic aneurysm accompanying with dissection. Median sternotomy was performed under selective cerebral perfusion to control bleeding when the aorta was injured. He was successfully replaced the ascending aorta and the aortic valve with the composite graft including an aortic prosthetic valve by modified Piehler's procedure. Case 2: A 44-year-old man received mitral valve replacement and tricuspid annuloplasty due to mitral regurgitation with tricuspid regurgitation. After surgery, he suffered from mediastinitis. Three months later, he was found to have pseudoaneurysm of the ascending aorta. During the sternotomy done under selective cerebral perfusion, the pseudoaneurysm was injured but bleeding was controlled easily. The defect of the aorta was closed successfully using a Dacron patch and covered with the right sternocleidomastoid muscle flap. Sternotomy under selective cerebral perfusion is very useful and safe for such patients as to have risks to injure the aorta or the heart during the sternotomy.

Adult↗
PubMed1997

[Aortic arch replacement performed in emergency in a short-term after grafting for abdominal aortic aneurysm].

Two cases of successful staged replacement of multiple aortic aneurysms are reported. Case 1: A 65-year-old man was found to have abdominal aortic and aortic arch aneurysms. He underwent abdominal aneurysmectomy and Y-grafting in the first stage. A month after his discharge, he was transferred to our hospital because of abrupt chest pain. Two days later, he fell into shock and emergent aortic arch replacement was performed successfully. Case 2: A 46-year-old man was transferred to our hospital because of abrupt abdominal pain and shock. CT scan revealed the rupture of the abdominal aneurysm. He received emergent abdominal aneurysmectomy and Y-grafting successfully. Three months later, he was readmitted because of back pain. CT scan revealed DeBakey Type I dissecting aneurysm. After three days, PaO2 of blood gas analysis fell to 46 mmHg, and absent femoral pulsation and oliguria were also observed. Therefore, aortic arch replacement was performed in emergency. The intimal tear was found in the distal aortic arch. The both of cases are doing well 24 months and 10 months after surgery respectively. It is important to scrutinize the order of surgery for multiple aortic aneurysms and to control blood pressure properly after aneurysmectomy.

Aged↗
PubMed1997

[Quantification of brain perfusion SPECT with N-isopropyl-p-iodoamphetamine using noninvasive microsphere method: estimation of arterial input by dynamic imaging].

We have developed a noninvasive method to quantify brain perfusion SPECT with 123I-N-isopropyl-p-iodoamphetamine (IMP) using serial dynamic planar imaging of the initial transit phase. The method is based on the microsphere model, but does not require arterial sampling. Serial dynamic planar imaging was performed for 6 min after the bolus injection of IMP (167 MBq in 1.5 ml), followed by additional planar imaging at 20 min and SPECT scan thereafter. The total arterial input to the brain during the initial 5 min after injection was estimated by the injected dose, with the correction of the lung retention, divided by cardiac output (CO). CO was estimated from the initial transit of IMP in the right heart. Cardiac output index (COI), obtained from the integral of the first transit of IMP in the right heart divided by the injected dose, was calibrated by CO measured by Doppler ultrasonography. Regional cerebral blood flow (rCBF) obtained by this method in normal subjects was acceptable. However, the results may be influenced by the injection technique, and careful attention should be considered for clinical application of this method.

Adult↗