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Biomedical subjects

K Endo

Publications and source records attributed to K Endo.

At least 127 records · Page 7Linked to original sources
PubMed2000

mu-Opioid receptor inhibits N-type Ca2+ channels in the calyx presynaptic terminal of the embryonic chick ciliary ganglion.

A study was made on the mechanisms by which enkephalins inhibit synaptic transmission at calyx-type presynaptic terminals in the ciliary ganglion of chick embryos at stages 39-40. Excitatory postsynaptic currents (EPSCs) were recorded by nystatin-perforated patch clamp at low [Ca2+]o and high [Mg2+]o. [Leu5]enkephalin (L-ENK, 1-10 microM) reduced the quantal content (m) without changing the quantal size (q). This effect was antagonized by naloxone (1 microM). Similar results were observed under conventional whole-cell clamp of the postsynaptic neuron. A specific agonist of the mu-opioid receptor, [D-Ala2, M-Me-Phe4,Gly5]enkephalin-ol (DAMGO) reduced m without changing q. A specific agonist of the delta-opioid receptor, [d-Pen2, d-Pen5]enkephalin (DPDPE) also reduced m without changing q. Both L-ENK and [Met5]enkephalin (M-ENK) reduced the stimulus-dependent increment of the intraterminal Ca2+ concentration (Delta[Ca2+]t) without affecting the decay time constant of the intraterminal Ca2+ concentration and basal Ca2+ level. This effect was antagonized by naloxone. DAMGO reduced Delta[Ca2+]t more effectively than DPDPE. When extracellular Ca2+ was replaced by Ba2+, the stimulus-dependent increment of the intraterminal Ba2+ concentration (Delta[Ba2+]t) was also reduced by L-ENK or DAMGO. L-ENK reduced Delta[Ca2+]t even in the presence of 4-aminopyridine (4-AP), which blocks the transient K+ conductance during the falling phase of the presynaptic action potential. When N-type Ca2+ channels were blocked by omega-conotoxin GVIA (omega-CgTxGVIA), the Delta[Ca2+]t was no longer sensitive to L-ENK and DAMGO. It is suggested that enkephalins reduce the transmitter release through presynaptic opioid receptors. The mu-opioid receptor may suppress presynaptic Ca2+ influx by selectively inhibiting N-type Ca2+ channels.

Analgesics, Opioid↗
PubMed2000

Reconstruction of rat peripheral nerve gap without sutures using freeze-dried alginate gel.

Many materials have been used for artificial tubular prostheses to assist peripheral nerve gap reconstruction. However, the clinical use of these devices has been restricted because a microsurgical procedure requires specialized techniques and expensive equipment, such as operating microscope systems. Therefore the authors developed a new gluing method, without sutures, that uses freeze-dried alginate gel. A 7-mm gap in the sciatic nerve of rats was bridged with freeze-dried alginate gel. Regeneration was evaluated by electrophysiologic testing and histologic study. Eighteen weeks after surgery, functional reinnervation of motor and sensory nerves had occurred, as demonstrated by recovery of compound muscle action potentials (CMAP), compound nerve action potentials (CNAP), and somatosensory-evoked potentials (SEP). Histologically, many regenerated nerve fasciculi, including myelinated and unmyelinated fibers, were observed and the implanted alginate gel had disappeared. In conclusion, a gluing technique using alginate gel is a potential alternative to the conventional nerve autograft technique. Advantages include simple application and rapid repair. Freeze-dried alginate gel is a promising material for artificial nerve guides for peripheral nerves and also could be used for repair of disrupted pathways in central nervous tissue that is amorphous and cannot be sutured.

Action Potentials↗
PubMed2000

Cervical vertigo after hair shampoo treatment at a hairdressing salon: a case report.

STUDY DESIGN: A case report of cervical vertigo that occurred after shampoo treatment in a hairdressing salon. Abnormalities were detected on magnetic resonance images and magnetic resonance angiography scans. OBJECTIVES: To describe the diagnosis of cervical vertigo caused by neck hyperextension. SUMMARY OF BACKGROUND DATA: Neck hyperextension may induce vertigo and dizziness; the pathophysiology remains unclear, however, because subjective findings are usually difficult to document. METHODS: The diagnosis, treatment, and outcome of a patient with cervical vertigo that occurred after hair shampoo treatment in a hair dressing salon were assessed. RESULTS: Magnetic resonance angiography demonstrated narrowing of the left vertebral artery, whereas magnetic resonance imaging showed cerebellar infarction. Treatment included rest and drugs that activate cerebral circulation and prevent platelet aggregation. Improvement was noted within few days. CONCLUSIONS: The authors suggest that the hyperextended neck position during hair shampoo treatment in a beauty parlor may be a risk factor for back lifting or cerebellum vascular insufficiency. Public education should lead to avoidance of this position during hair shampoo treatment at hair dressing salons.

Beauty↗
PubMed2000

PCR survey of Hox genes in the crinoid and ophiuroid: evidence for anterior conservation and posterior expansion in the echinoderm Hox gene cluster.

To help elucidate the cluster organization of Hox genes in echinoderms, we amplified a homeobox region by polymerase chain reaction (PCR) and cloned and sequenced the PCR products for the comatulid crinoid Oxycomanthus japonicus and the ophiuroid Stegophiura sladeni. The crinoid had at least three anterior, four medial, and four posterior genes, and the ophiuroid had at least one anterior, three medial, and six (one of which being a possible trans-paralog) posterior genes. The survey of the crinoid detected all three anterior complements (PG1-3 genes). It was inferred that the Hox genes of each species are organized into a single cluster and that a novel cognate group of echinoderm posterior genes (tentatively termed HboxP9) exists among echinoderms in addition to the known posterior genes Hbox4, Hbox7, and Hbox10. The results, combined with the data of other echinoderm classes, strongly suggest that the presence of a single Hox gene cluster is a common feature among echinoderms and that the cluster has the general features of the deuterostome Hox gene cluster, i.e., the anterior conservation and posterior expansion. The results of the ophiuroid imply that the posterior genes in this class diversified after the phylum Echinodermata had been established.

Alleles↗
PubMed2000

Mitochondrial COI sequences of brachiopods: genetic code shared with protostomes and limits of utility for phylogenetic reconstruction.

A 1230-bp region of the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA of each of 16 brachiopod species, representing all five living orders, was amplified by polymerase chain reaction and sequenced. Pairwise comparisons of sequence differences plotted against divergence times estimated from the brachiopod fossil record revealed that, although there are considerable variations in the expected substitution rate among different lineages, amino acid substitutions of the COI sequences may largely become saturated in 100 Ma, due mostly to multiple substitutions at the same site. Coinciding with this result, phylogenetic analysis indicated low bootstrap values for nodes corresponding to divergence events that occurred before 100 Ma, suggesting that COI sequences are suitable only for inference of phylogenetic events subsequent to the Mesozoic. Examination of brachiopod codons corresponding to invariant amino acids in the COI of various other animals suggest the nonuniversal codon relationships UGA = Trp, AUA = Met, AAA/G = Lys, and AGA/G = Ser. These are identical to those in mollusks, annelids, and arthropods, consistent with the conclusion that brachiopods are protostomes, as indicated by previous molecular analyses.

Animals↗
PubMed2000

The clinicopathological significance of preoperative serum-soluble interleukin-2 receptor concentrations in operable non-small-cell lung cancer patients.

BACKGROUND: Serum-soluble interleukin-2 receptor (IL-2R) concentrations have been found to be elevated in cancer patients. However, the importance of this finding in patients with non-small-cell lung cancer (NSCLC) has not been previously established. METHODS: Preoperative serum-soluble IL-2R concentrations were determined in 65 consecutive patients with operable NSCLC. The correlation of preoperative serum-soluble IL-2R concentrations with various clinicopathological features of this cancer was evaluated to clarify the clinical significance of this parameter. RESULTS: Although serum-soluble IL-2R concentrations were not significantly higher in operable NSCLC patients than in normal controls (P = .1180), serum-soluble IL-2R concentrations were significantly higher in patients with stage IIIB or IV disease than in normal controls (P = .0001). The presence of intrapulmonary metastasis was the only clinicopathological feature that was significantly correlated to serum-soluble IL-2R concentration (P = .0004). The sensitivity of serum-soluble IL-2R concentration in identifying the presence of intrapulmonary metastasis was 87.5%; specificity was 75%. CONCLUSIONS: Elevated preoperative serum-soluble IL-2R concentrations in patients with operable NSCLC reflect the occurrence of intrapulmonary metastasis. Preoperative examination of serum-soluble IL-2R concentrations may be valuable in the detection of the intrapulmonary metastasis preoperatively.

Aged↗
PubMed2000

Fundamental study of hot spot detectability in 3-dimensional positron emission tomography.

The purpose of this study was to investigate the detectability of small hot lesions with the 3-dimensional transmission/emission (3D T/E) acquisition mode in FDG-PET scan. The correlation of target detectability, target size, target to non-target uptake ratio (T/N ratio) and standardized uptake value (SUV) were studied. Small hot lesions ranged from 4.4 mm to 36.9 mm in diameter were located in cylindrical phantom. The images of phantoms with a T/N ratio of 2.0, 4.0, 6.0, 8.0, 9.6, 13.2, 17.5, 23.8 and 30.3 were obtained with 2-dimensional transmission/emission (2D T/E) scan and 3D T/E scans. Targets in diameter more than 10.6 mm in diameter with an actual T/N ratio ranged from 6.0 to 30.3 could be identified on the images obtained with all the 2D T/E and 3D T/E acquisition modes. The detectability efficiency of small hot target in 2D T/E and 3D T/E scans was as same (77.8%). The T/N ratio of targets from 2D T/E images was 30% to 48.4% different to that from 3D T/E image, and the SUV of the target from the 2D T/E images was almost the same as that from 3D T/E images. This study revealed that 3D T/E scanning had similar hot spot detectability to 2D T/E scanning; 3D T/E and 2D T/E scanning had the same faculty for semiquantitative analysis using SUV. These findings may be helpful for the diagnosis and understanding of 3D T/E FDG-PET in hot lesion detection.

Fluorine Radioisotopes↗
PubMed2000

Multifocal low-signal brain lesions on T2*-weighted gradient-echo imaging.

Multifocal small low-signal lesions on T2*-weighted gradient-echo (GE) MRI are reported to be common in the brain of hypertensive patients. We examined factors associated with these lesions. For one year, we routinely obtained T2*-weighted GE images (TR 1000 TE 30 ms, flip angle = 20 degrees) in all adult patients (314) who underwent brain MRI in our hospital, using a 1.5 T superconducting magnet. Patients with multifocal small low-signal lesions with a known or presumed pathogenesis or any condition which may cause intracerebral haemorrhage, such as brain tumours, were excluded from further analysis. Thus, 191 cases remained (104 men and 87 women; age, 62.8+/-11.0 years, range, 30-89 years). The overall prevalence of multifocal small low-signal lesions on the GE images was 15.2% (29/191); they were commonly in the cerebral white matter and basal ganglia. They were detected in 12 (52.2%) of the 23 patients with prior symptomatic brain hemorrhage, 12 (20.7%) of the 58 with prior symptomatic infarcts, and only five (4.5%) of 110 without a prior stroke. Logistic regression analysis indicated that multifocal small low-signal lesions were significantly correlated with a symptomatic acute brain haemorrhage (odds ratio, 13.17), chronic hypertension (4.00) and a symptomatic acute infarct (3.71). The association with symptomatic acute brain haemorrhage suggests that this finding may represent subclinical microhaemorrhage. The diagnostic potential of this finding to identify individuals at risk of symptomatic intracerebral haemorrhage may require further investigation.

Adult↗
PubMed2000

PET imaging of musculoskeletal tumours with fluorine-18 alpha-methyltyrosine: comparison with fluorine-18 fluorodeoxyglucose PET.

Fluorine-18 labelled alpha-methyltyrosine (FMT) was developed for positron emission tomography (PET) imaging, and its potential for clinical application in patients with brain tumours has been demonstrated. This is the first trial to compare FMT with 18F-fluoro-2-deoxy-D-glucose (FDG) for the evaluation of musculoskeletal tumours. Seventy-five patients were examined with both FMT- and FDG-PET within a 2-week period. Imaging findings were visually inspected in conjunction with computed tomography and/or magnetic resonance imaging, and standardized uptake values (SUVs) for both FMT and FDG in lesions were also generated and compared with histological findings. A significant correlation between FMT and FDG SUVs was found for all lesions (r=0.769, P<0.0001), and mean values for malignant tumours were significantly higher than those for benign lesions in both FMT- and FDG-PET. The diagnostic sensitivities and specificities for malignancy were 72.7% and 84.9%, respectively, using FMT with a cut-off SUV of 1.2, and 72.7% and 66.0%, respectively, using FDG with a cut-off SUV of 1.9. The resultant accuracy with FMT was 81.3%, higher than that for FDG (68.0%), and the difference with respect to specificity was significant (chi2cal=5.0625, P<0.05). On the other hand, while a significant correlation was found between malignant tumour grade and SUV with both FMT- (rho=0.656) and FDG-PET (rho=0.815), only the latter demonstrated significant differences among grades I, II and III. FMT and FDG for PET appear equally effective at detecting musculoskeletal tumours. In evaluating musculoskeletal tumours, FMT may be superior to FDG in the differentiation between benign and malignant tumours, while FDG may be the better choice for non-invasive malignancy grading.

Adolescent↗
PubMed2000

Patterning defects in the primary axonal scaffolds caused by the mutations of the extradenticle and homothorax genes in the embryonic Drosophila brain.

During early brain development in Drosophila a highly stereotyped pattern of axonal scaffolds evolves by precise pioneering and selective fasciculation of neural fibers in the newly formed brain neuromeres. Using an axonal marker, Fasciclin II, we show that the activities of the extradenticle (exd) and homothorax (hth) genes are essential to this axonal patterning in the embryonic brain. Both genes are expressed in the developing brain neurons, including many of the tract founder cluster cells. Consistent with their expression profiles, mutations of exd and hth strongly perturb the primary axonal scaffolds. Furthermore, we show that mutations of exd and hth result in profound patterning defects of the developing brain at the molecular level including stimulation of the orthodenticle gene and suppression of the empty spiracles and cervical homeotic genes. In addition, expression of a Drosophila Pax6 gene, eyeless, is significantly suppressed in the mutants except for the most anterior region. These results reveal that, in addition to their homeotic regulatory functions in trunk development, exd and hth have important roles in patterning the developing brain through coordinately regulating various nuclear regulatory genes, and imply molecular commonalities between the developmental mechanisms of the brain and trunk segments, which were conventionally considered to be largely independent.

Animals↗
PubMed2000

Overexpression of MDM2 protein in intrahepatic cholangiocarcinoma: relationship with p53 overexpression, Ki-67 labeling, and clinicopathological features.

Aberration of the p53 gene is thought to be the most frequent genetic alteration in human cancers. Tp53 protein may be inactivated by the binding of the MDM2 protein. MDM2, the product of the mdm2 gene, is an oncoprotein that binds to Tp53 and inhibits the p53-mediated transactivation. MDM2 overexpression has been reported in several human cancers, but not in intrahepatic cholangiocarcinoma (ICC). Therefore, we have evaluated the immunohistochemical overexpression of MDM2 and the relationship between its expression and histological grade, clinicopathological features, Tp53 overexpression, and Ki-67 labeling index in 47 cases of ICC. MDM2 and Tp53 were found to be overexpressed in 38% and 57% of the tumor, respectively. MDM2 and Tp53 were not expressed in non-tumorous liver tissue. There was no significant difference between the MDM2 overexpression and ICC tumor grade. However, MDM2 overexpression correlated with the presence of metastases (P<0.01) and advanced tumor stage (P<0.05). MDM2 overexpression also correlated with Tp53 overexpression (P<0.03) and Ki-67 labeling index (P<0.03). Our findings suggest that MDM2 overexpression may play a role in the late stage of human ICC.

Bile Duct Neoplasms↗
PubMed2000

The effect of hybrid layer thickness on bond strength: demineralized dentin zone of the hybrid layer.

OBJECTIVES: The purpose of this study was to evaluate the correlation between hybrid layer thickness and bond strength using specimens acid-conditioned for varying lengths of time. METHODS: The dentin surfaces of human premolars, sectioned to remove the enamel from the labial surface, were conditioned with 35.0% phosphoric acid of an adhesive resin system (Scotchbond Multi-Purpose; 3M) for 15 (as directed by the manufacturer), 60, 120, or 180 s (experimental acid-conditioning times). The bonded specimens were then sectioned perpendicular to the adhesive interface to measure the hybrid layer thickness by SEM. The specimens for the micro-tensile test were sectioned perpendicular to the adhesive interface and trimmed to an hourglass-shape. Then, the micro-tensile test was performed at a crosshead speed of 1.0 mm/min. The bond strengths and hybrid layer thickness were statistically compared with Student's t-test (p < 0.05). All fractured surfaces were also observed by SEM. RESULTS: Significant differences between the groups exposed to acid for 15 and 60 s, and those exposed for 120 and 180 s were observed in hybrid layer thickness and bond strength (p < 0.05). SEM observation of the fractured surfaces revealed that a demineralized dentin zone without resin impregnation remained within the hybrid layer. SIGNIFICANCE: A demineralized dentin zone was formed in the bond structures after prolonged acid-conditioning, resulting in low bond strength. The shrinkage of the hybrid layer due to desiccation during the SEM examination process provided evidence of the presence of the demineralized dentin zone within the hybrid layer.

Acid Etching, Dental↗
PubMed2000

Protein expression of CD44 (standard and variant isoforms) in hepatocellular carcinoma: relationships with tumor grade, clinicopathologic parameters, p53 expression, and patient survival.

BACKGROUND/AIMS: Members of the CD44 family are transmembrane glycoproteins which act mainly as receptors for hyaluronan. We have examined the expression of CD44s and several CD44v and the relationship between these and hepatocellular carcinoma (HCC) grade, clinicopathological parameters, p53 expression, and patient survival in HCC. METHODS: Formalin-fixed, paraffin-embedded tissue sections from 107 surgically resected HCC were examined immunohistochemically using a semi-quantitative scoring system to detect the expression of different forms of CD44. RESULTS: The number of CD44s-positive cases was 36 (34%), CD44v5 52 (49%), CD44v6 29 (27%), CD44v7-8 41 (38%), and CD44v10 26 (24%). Expression of these molecules correlated with high histological grade, being the highest in poorly-differentiated HCC. High CD44v6 expression significantly correlated with the presence of vascular invasion and p53 overexpression. Kaplan-Meier examination of patient survival revealed that HCC patients with positivity of each of these five molecules had a reduced survival rate, and that HCC patients positive for all the five CD44 molecules had worse survival than HCC patients positive for four or less of these CD44 molecules. In multivariate survival analysis, CD44s positivity was an independent factor. However, positivity for one or more CD44 isoforms was the most useful independent factor for overall survival. CONCLUSION: These results suggest that up-regulation of CD44 isoforms is associated with poorly-differentiated HCC and shortened survival.

Adolescent↗
PubMed2000

Spleen enlargement in patients with nonalcoholic fatty liver: correlation between degree of fatty infiltration in liver and size of spleen.

Our purpose was to determine if there is an association between nonalcoholic fatty liver and spleen enlargement. Spleen volume was measured by computed tomography (CT) in 32 patients with nonalcoholic fatty liver (23 men and 9 women; age, 41.6+/-12.1, range, 22-69 years) and 34 patients with normal liver (19 men and 15 women; age, 51.1+/-16.2, range, 14-86 years). The values were compared with the patient's demographic data, the liver-to-spleen (L/S) ratio of CT Hounsefield unit measurements, and the results of liver function tests. Diagnosis of fatty liver was made if the L/S ratio was less than 1.0. The mean spleen volume was 73.0+/-24.4 cm3 (range, 21.1-106.1) in normal subjects and 141.2+/-54.1 cm3 (range, 44.1-267.3) in patients with fatty liver (P<0.0001). Multivariate linear regression analysis identified that only the L/S ratio (P<0.0001) and age (P<0.01) were significantly correlated with spleen volume. Using forward selection stepwise regression, the L/S ratio entered first (beta = -0.634) and age second (beta = -0.293). In conclusion, spleen enlargement was commonly seen in patients with nonalcoholic fatty liver, and the recognition of this association may halt further attempts to evaluate the cause of spleen enlargement.

Adult↗
PubMed2000

Carbon-source-dependent transcriptional control involved in the initiation of cellular differentiation in Streptomyces griseus.

Carbon source is one of the environmental factors that affects cellular differentiation of Streptomyces. We have identified the craA gene as a putative negative regulator involved in the carbon-source-dependent initiation of cellular differentiation in Streptomyces griseus. Carbon-source-dependent transcriptional repression of craA, which is caused by binding of a putative repressor protein to its promoter region, is proposed to result in the initiation of aerial mycelium formation. The presence of a craA homologue in the chromosome of Streptomyces coelicolor A3(2) implicates the existence of a similar regulatory mechanism in this organism. The repression of craA-promoter activity in glucose media could be alleviated not only by replacing glucose with maltose but also by supplying copper, which suggests that the stimulatory effect of copper on cellular differentiation in Streptomyces is excerted via abolishment of glucose-repression of craA.

Amino Acid Sequence↗