Biomedical subjects

S Nagasaki

Publications and source records attributed to S Nagasaki.

At least 19 recordsLinked to original sources

PubMed2004

Association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men.

AIM: We investigated the association of habitual long-distance running with the thickness of skeletal muscles and subcutaneous fat in the body extremities and trunk in middle-aged men using ultrasonography. METHODS: Three groups of healthy middle-aged men [mean (SD), 62.1 (2.8) years] took part in this investigation: a high-level group of 11 master runners who had competed in a 42.195 km race and run 51.6 (21.7) km every week, an intermediary-level group of 10 master runners who had competed in a 5-20 km race and run 9.3 (4.9) km every week, and a low-level group of 7 untrained men who continued to do no systematic training. The muscle thickness at 8 sites and the subcutaneous fat thickness at 10 sites were measured by B-mode ultrasonography, and were compared among the 3 groups. RESULTS: The high-level group had 10.0(-1)5.2% higher values for muscle thickness at the erector spinae, hamstrings, tibialis anterior, and triceps surae, compared with the intermediary-level and the low-level groups (p<0.05-0.001). The thickness of the subcutaneous fat about the rectus abdominis and external oblique was lower in the high-level group than in the intermediary-level and the low-level groups (p<0.05). CONCLUSIONS: Middle-aged male master athletes who habitually run at a high level have more muscle thickness in the lower extremities and trunk, and less subcutaneous fat thickness in the central regions of the body than do middle-aged men who habitually run at an intermediary level or do not run at all.

Abdominal Muscles↗

PubMed2000

Impairment of spatial memory and changes in astroglial responsiveness following loss of molar teeth in aged SAMP8 mice.

In order to evaluate the mechanism(s) responsible for senile impairment of cognitive function as a result of reduced mastication, the effects of the loss of the molar teeth (molarless condition) on the hippocampal expression of glial fibrous acidic protein (GFAP) and on spatial memory in young adult and aged SAMP8 mice were studied using immunohistochemical and behavioral techniques. Aged molarless mice showed a significantly reduced learning ability in a water maze test compared with age-matched control mice, while there was no difference between control and molarless young adult mice. Immunohistochemical analysis showed that the molarless condition enhanced the age-dependent increase in the density and hypertrophy of GFAP-labeled astrocytes in the CA1 region of the hippocampus. These effects increased the longer the molarless condition persisted. When the extracellular K+ concentration ([K+]o) was increased from 4 to 40 mM for hippocampal slices in vitro, the mean increase in the membrane potential was about 57 mV for fine, delicate astrocytes, the most frequently observed type of GFAP-positive cell in the young adult mice, and about 44 mV for the hypertrophic astrocytes of aged mice. However, there was no significant difference in resting membrane potential between these cell types. The data suggest that an impairment of spatial memory and changes in astroglial responsiveness occur following the loss of molar teeth in aged SAMP8 mice.

Aging↗

PubMed1999

Epstein-Barr virus infection of the colon with inflammatory bowel disease.

OBJECTIVE: Epstein-Barr virus (EBV)-infected cells can evoke severe host immune responses, as shown in infectious mononucleosis and EBV-associated gastric carcinoma. To investigate the possible pathological role of EBV in inflammatory bowel disease (IBD), we tested for the presence of EBV in the colon in IBD patients. METHODS: Surgically resected colonic specimens of 11 patients with Crohn's disease, five patients with ulcerative colitis, nine noninflammatory controls (disease-free area of the colorectal carcinoma), and 10 appendicitis cases were tested using highly sensitive in situ hybridization for EBV-encoded small RNA1 (EBER-1). RESULTS: EBER-1 was detected in 63.6% of Crohn's disease cases and 60% of ulcerative colitis cases, but not at all in noninflammatory controls and appendicitis cases. EBER-1-positive cells were very rare in the noninflammatory areas of colonic specimens from IBD patients. EBER-1-positive cells were nonepithelial cells (mainly B lymphocytes and a few histiocyte-shaped cells) located in erosive or ulcerative areas of the colonic specimens. CONCLUSION: The limited presence of EBV-infected cells in the diseased areas of IBD colonic specimens indicated that EBV infection may be related to such diseases.

Adult↗

PubMed1999

Origin of primary sensory neurons innervating the buccal stretch receptor.

The primary sensory neurons innervating mechanoreceptors in oro-facial regions have their cell bodies in either the trigeminal ganglion or the mesencephalic nucleus of the trigeminal nerve. The buccal stretch receptor (BSR), a type of mechanoreceptor in the jaw of rodents, has recently been recognized as signaling the position of the mandible. The location of the primary afferent neurons innervating this receptor is unknown. To investigate the cell bodies of the BSR afferent neurons in rats, we applied wheat germ agglutinin-horseradish peroxidase (WGA-HRP) to the proximal stump of the severed nerve branch of the buccal nerve that supplied the BSR. HRP-labeled cell bodies were observed in the posterolateral portion of the ipsilateral trigeminal ganglion. None was found in the contralateral trigeminal ganglion or in the brainstem. All labeled cell bodies were oval or round and closely resembled pseudo-unipolar neurons. The mean diameter of the labeled somata ranged between 25.5 and 52.5 microm, with small (< or = 30 microm), medium (from 31 to 40 microm), and large somata (> or = 41 microm) accounting for 8.8%, 54.9%, and 36.3%, respectively. Among the myelinated nerve fibers in the branch in which WGA-HRP was applied, 78.5% terminated in the BSR and had larger fiber diameters than the rest, indicating that most of the medium and large HRP-labeled cell bodies were BSR afferents. From these results and the ontogenetic origin of this receptor, it is suggested that the BSR differentiated from the mechanoreceptors in the oral mucosa or the fascia of masticatory muscles.

Animals↗

PubMed1998

Laparoscopic repair for perforation of duodenal ulcer with omental patch: report of initial six cases.

We report our initial experience with perforated duodenal ulcer treated by laparoscopic repair with omental patch in six patients, and the results are compared with those of other procedures retrospectively. The average operative time was 85.0 min, and the estimated blood loss was 13.7 ml. The estimated blood loss of laparoscopic repair was significantly less than that of gastrectomy (p < 0.01). However, although all patients with gastrectomy or open omental patch needed administration of analgesia, only half of patients require analgesia in laparoscopic repair. No postoperative complication was encountered, and the recurrence of ulcer was not recognized in a mean follow-up of 10 months. We recognized this procedure to be safe and feasible. Although a larger number of patients with longer follow-up is needed, this procedure may become one of the treatments for perforated duodenal ulcer.

Adult↗

PubMed1997

Synchronous multiple colorectal adenocarcinomas.

BACKGROUND: The object of the present work was to characterize clinical features and the quality of preoperative examinations in patients with synchronous colorectal carcinomas, and to compare the incidence of associated benign polyps with our findings in patients with a single malignant lesion. METHODS: A retrospective evaluation of 225 patients with primary colorectal carcinoma revealed 9 cases (4.0%) of synchronous colorectal carcinomas. RESULTS: The synchronous colorectal carcinomas were located in the same anatomical segment in 7 patients and were divided into different segments in 2 patients. The accuracy of preoperative diagnosis was 55.6% by endoscopy alone and 66.7% by double contrast barium enema (DCBE) alone, while the rate was 77.8% when colonoscopy and DCBE were combined. There was a higher incidence of associated benign polyps in the group with synchronous colorectal carcinomas (55.6%) versus 28.7% for a single carcinoma (P < 0.05). The main reason why multiple lesions could not be identified preoperatively was that the distal lesions prevented examination of the proximal lesions. CONCLUSIONS: At the time of surgical resection, it is important to ascertain preoperatively whether or not a second lesion exists. If synchronous polyps are present in patients with synchronous colorectal carcinomas, they should be ablated to reduce the risk of metachronous colorectal carcinoma.

Adenocarcinoma↗

PubMed1997

Strip biopsy to treat esophageal granular cell tumor.

Esophageal granular cell tumors are rare neoplasms. We successfully treated a 35-year-old Japanese man with an esophageal granular cell tumor without any complications using strip biopsy. Endoscopic ultrasonography revealed a hypoechoic tumor with a diameter of 8 mm that was confined to the submucosal layer. A strip biopsy done with a two-channel endoscope completely resected the tumor. Six months later, no abnormal findings were recognized in the resected area. Therefore we propose that strip biopsy be considered as a viable alternative treatment for esophageal granular cell tumor, depending on the histologic character, tumor size, and depth of tumor infiltration.

Adult↗

PubMed1997

A novel glutamate-mediated inhibitory mechanism linked with Ca2+/calmodulin-dependent protein kinase II in identified Euhadra neurons.

The underlying mechanism(s) of the glutamate (Glu)-induced membrane hyperpolarizing response in identified Euhadra neurons was investigated using the voltage-clamp technique, pressure injection method, and pharmacologic agents. Under voltage-clamp conditions, bath-applied Glu elicits a slow outward potassium current (Glu current) accompanied by an increase in membrane conductance whose amplitude is dose dependent. Of the agonists tested, the Glu current was mimicked only by quisqualate (QA); its potency was approximately 10 times greater than that of Glu. Typical antagonists for the ionotropic type of Glu receptors and G protein inhibitors do not block this current. The Glu current is markedly enhanced by a specific inhibitor of Ca2+/ calmodulin-dependent protein kinase II (CaM-KII), KN-62 (1-[N,O-bis (1,5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine) in a dose-dependent manner, while intracellularly injected CaM-KII suppresses the current. The potent protein kinase A inhibitors, H-8 (N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride) and H-89 (N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide) or the specific protein kinase C inhibitors staurosporine and K-252b had no effect on the Glu current. These results suggest the presence of a novel subtype of Glu receptor in Euhadra neurons, which may be coupled to the activation of potassium channels normally suppressed by CaM-KII.

Animals↗

PubMed1996

Structural and functional maturation of the buccal stretch receptors in rats.

Postnatal functional and structural development of the buccal stretch receptor (BSR) of rats was investigated, using electrophysiological and morphological techniques. For functional analysis, sustained discharges in response to ramp-and-hold stretches were recorded from the BSRs isolated from animals aged 10 days to 10 weeks. The threshold amplitude of stretch for a sustained discharge fell significantly between 10 days and 3 weeks, reaching adult values at 5 weeks of age, while the static sensitivity increased conspicuously between 2 and 4 weeks after birth. On the other hand, between 1 and 4 weeks of age, apparent structural changes in the BSR were observed on the number of preterminal branches in a sensory unit, the size of the varicose-like swellings along the terminal axon, the density of collagen and elastic fibers around the core structure, and the content of the sub-capsular space. From these results, we suggest that the increase in the density of the connective tissue around the core structure is associated with an enhancement in the elasticity of the BSR in the early postnatal stages, decreasing the threshold amplitude of stretch for a sustained discharge. One possible explanation for the maturation of the static sensitivity of this receptor is growth of the sensory axon terminals filled with dense mitochondria.

Animals↗

PubMed1996

Endoscopic ultrasonography of superficial esophageal cancers using a thin ultrasound probe system equipped with switchable radial and linear scanning modes.

BACKGROUND: Detailed information on the depth of invasion of superficial esophageal cancer is required for endoscopic mucosal resection. As a pretherapeutic diagnostic procedure, endoscopic ultrasonography using conventional 7.5 MHz systems has been ineffective at providing sufficient details. A newly developed, thin ultrasound probe system provides both radial and linear scanning for evaluation of superficial esophageal cancer. METHODS: Endoscopic ultrasonography was performed in 16 patients using a switchable probe driven at 20 MHz. Seventeen lesions of superficial esophageal cancer were evaluated for depth of invasion to discriminate mucosal from submucosal penetration. RESULTS: The overall accuracy of staging was 64.7%. In all six errors, mucosal cancers were overstaged as submucosal invasion. The diagnostic accuracy was 80% when the muscularis mucosae was visualized. CONCLUSION: A 20 MHz linear-radial switchable probe is a useful new method in the staging of superficial esophageal cancer.

Aged↗

PubMed1995

Maturation of static sensitivity is related to expansion of the capsular space in rat buccal stretch receptors.

The developmental relationship between static sensitivity and structure of the buccal stretch receptor (BSR) in rats was investigated. When responses to ramp-and-hold stretches were recorded from isolated BSRs, their static sensitivities suddenly increased between 2 and 4 weeks after birth. However, no apparent change was observed throughout other developmental stages examined. Electron microscopic examination revealed a conspicuous expansion of the fluid-filled capsular space caused by completion of the outer capsule during the same postnatal period. These findings suggest that an increase in the capsular space of BSR may be involved in increasing the static sensitivity of this receptor.

Aging↗

PubMed1995

Gene cloning, purification, and characterization of thermostable and halophilic leucine dehydrogenase from a halophilic thermophile, Bacillus licheniformis TSN9.

A halophilic and thermophilic isolate from the sand of Tottori Dune was found to produce a thermostable and halophilic leucine dehydrogenase (EC 1.4.1.9). It was identified to be a new strain of Bacillus licheniformis. The enzyme gene was cloned into Escherichia coli JM109 with a vector plasmid pUC18. The enzyme was purified to homogeneity from the clone cell extract by ion-exchange column chromatography with a yield of 31%. The enzyme was found to be composed of eight subunits identical in relative molecular mass (43,000). The amino acid sequence of the enzyme, deduced from the nucleotide sequence of the gene, showed an identity of 84.6% with that of the B. stearothermophilus enzyme [Nagata S, Tanizawa K, Esaki N, Sakamoto Y, Oshima T, Tanaka H, Soda K (1988) Biochemistry 27:9056-9062], although both enzymes were similar to each other in various enzymological properties such as thermostability, substrate and coenzyme specificities, and stereospecificity for hydrogen transfer from the C-4 of NADH. However, they were markedly distinct from each other in halophilicity; the B. licheniformis enzyme was much more stable than the other in the presence of high concentrations of salts.

Amino Acid Oxidoreductases↗

PubMed1993

Lidocaine suppresses the sodium current in Euhadra neurons which is mediated by cAMP-dependent protein phosphorylation.

The action of a local anesthetic, lidocaine, in association with the cyclic AMP (cAMP)-mediated intracellular biochemical process, was examined in identified Euhadra neurons. Lidocaine dose-dependently inhibited the inward current which was elicited by dibutyryl cAMP (db-cAMP) and isobutylmethylxanthine (IBMX). This inhibitory effect was transiently reversed by the intracellular injection of a catalytic subunit of a cAMP-dependent protein kinase. The inward current elicited by db-cAMP and IBMX was abolished by Na(+)-free saline but not by Ca(2+)-free saline. The data suggest that lidocaine is not acting directly on the Na+ channel, but acts at a level proximal to the catalytic subunit of cAMP-dependent protein kinase.

1-Methyl-3-isobutylxanthine↗

PubMed1993

An inducible NADP(+)-dependent D-phenylserine dehydrogenase from Pseudomonas syringae NK-15: purification and biochemical characterization.

An inducible NADP(+)-dependent D-phenylserine dehydrogenase [EC 1.1.1.-], which catalyzes the oxidation of the hydroxyl group of D-threo-beta-phenylserine, was purified to homogeneity from a crude extract of Pseudomonas syringae NK-15 isolated from soil. The enzyme consisted of two subunits identical in molecular weight (about 31,000). In addition to D-threo-beta-phenylserine, it utilized D-threo-beta-thienylserine, D-threo-beta-hydroxynorvaline, and D-threonine as substrates but was inert towards other isomers of beta-phenylserine and threonine. It showed maximal activity at pH 10.4 for the oxidation of D-threo-beta-phenylserine, and it required NADP+ as a natural coenzyme. NAD+ showed a slight coenzyme activity. The enzyme was inhibited by p-chloromercuribenzoate, HgCl2, and monoiodoacetate but not by the organic acids such as tartronate. The Michaelis constants for D-threo-beta-phenylserine and NADP+ were 0.44 mM and 29 microM, respectively. The N-terminal 27 amino acids sequence was determined. It suggested that the NADP(+)-binding site was located in the N-terminal region of the enzyme.

Alcohol Oxidoreductases↗

PubMed1993

NADP(+)-dependent D-threonine dehydrogenase from Pseudomonas cruciviae IFO 12047.

NADP(+)-dependent D-threonine dehydrogenase (EC 1.1.1.-), which catalyzes the oxidation of the 3-hydroxyl group of D-threonine, was purified to homogeneity from a crude extract of Pseudomonas cruciviae IFO 12047. The enzyme had a molecular mass of about 60,000 Da and consisted of two identical subunits. In addition to D-threonine, D-threo-3-phenylserine, D-threo-3-thienylserine, and D-threo-3-hydroxynorvaline were also substrates. However, the other isomers of threonine and 3-phenylserine were inert. The enzyme showed maximal activity at pH 10.5 for the oxidation of D-threonine. The enzyme required NADP+. NAD+ showed only slight activity. The enzyme was not inhibited by EDTA, o-phenanthroline, alpha,alpha'-dipyridyl, HgCl2, or p-chloromercuribenzoate but was inhibited by tartronate, malonate, pyruvate, and DL-2-hydroxybutyrate. The inhibition by these organic acids was competitive against D-threonine. Initial-velocity and product inhibition studies suggested that the oxidation proceeded through a sequential ordered Bi Bi mechanism. The Michaelis constants for D-threonine and NADP+ were 13 and 0.12 mM, respectively.

Alcohol Oxidoreductases↗

PubMed1993

[A case of nonresectable esophageal cancer treated by the combination of cisplatin, 5-fluorouracil and THP-adriamycin].

An advanced esophageal cancer patient with multiple liver metastases was treated with a combination of CDDP, 5-FU and THP-ADM. Complete response was obtained against esophageal primary lesion endoscopically, and partial response was obtained against liver metastases observed by computed tomography. Bone marrow suppression of grade 3 was observed, but resolved within 2 weeks.

Antibiotics, Antineoplastic↗

PubMed1992

Clinicopathological significance of c-erbB-2 protein expression in human gastric carcinoma.

One hundred seventy-nine primary human gastric tumors not associated with early cancer or noncurative resection were examined immunohistochemically for the expression of c-erbB-2 protein. Positive staining, regarded as an indication of gene amplification, was evident in 22(12%) of the tumors. Of various clinicopathological factors considered, a statistically significant difference in association with frequency of expression was noted only for histological differentiation, as follows: 39% positive staining in papillary, 17% in well differentiated, 5% in moderately differentiated, and 4% in undifferentiated adenocarcinomas (P greater than 0.01). The 5-year survival rates of patients with positive and negative c-erbB-2 staining were 57% and 59%, respectively. These findings indicate that, in the case of human gastric adenocarcinoma, expression of c-erbB-2 protein is correlated with tumor histological differentiation. Our results also suggest that the presence or absence of c-erbB-2 protein may not serve as a prognostic indicator, particularly in cases of adenocarcinoma of the stomach.

Adenocarcinoma↗

PubMed1992

A 94 year old male stage IV breast cancer patient showing complete remission under tamoxifen treatment after operation.

A 94 year old man with an invasive ductal carcinoma of the breast (T4N2M1, stage IV), underwent a modified radical mastectomy to improve his quality of life. The estrogen receptor status of both the breast tumor and the metastatic axillar lymph nodes was high. Immunohistochemical staining for epidermal growth factor, epidermal growth factor receptor, or c-erbB-2 protein was negative. The patient received only tamoxifen continuously for 3 months, and later apparently showed a complete remission. Therefore, in advanced male breast cancer with a high estrogen receptor status, operation in conjunction with hormone therapy may lead to a favorable result in some cases.

Aged↗