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Biomedical subjects

S Ohashi

Publications and source records attributed to S Ohashi.

At least 73 records · Page 4Linked to original sources
PubMed1999

Quantitation and isomeric structure analysis of free oligosaccharides present in the cytosol fraction of mouse liver: detection of a free disialobiantennary oligosaccharide and glucosylated oligomannosides.

The amounts and isomeric structures of free oligosaccharides derived from N-linked sugar chains present in the cytosol fraction of perfused mouse liver were analyzed by tagging the reducing end with 2-aminopyridine followed by 2-dimensional HPLC mapping with standard sugar chains. Sixteen pyridylaminated (PA-) oligomannosides terminating with a PA-GlcNAc residue (GN1-type), three glucose-containing oligomannosides, and four oligomannosides terminating with a PA-di-N-acetylchitobiose (GN2-type) were detected. The total contents of the GN1- and GN2-type oligomannosides were 3. 4 and 0.5 nmol, respectively, per gram of wet tissue. Maltooligosaccharides (dimer to pentamer) were also detected, the total content of which was 13 nmol per gram of wet tissue. Besides these oligosaccharides, a PA-disialobiantennary sugar chain-the sole complex-type sugar chain-was also detected. All the oligomannosides identified had partial structures of Glc(3)Man(9)GlNAc(2)-p-p-dolichol, revealing that they were metabolic degradation products. Manalpha1-2Manalpha1-2Manalpha1-3(Manalpha1-6)++ +Manbeta1-4GlcNAc (M5B') was the major oligomannoside, suggesting that cytosolic endo-beta-N-acetylglucosaminidase and neutral alpha-mannosidase participate in the degradation, because these enzymes have suitable substrate specificities for the production of M5B'. Degradation by these enzymes seems to be the main pathway by which oligomannosides are degraded in mouse cytosol; however, small amounts of Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) Manbeta1-4(GlcNAc)1-2 and related oligomannosides together with parts of their structures were also detected, suggesting that there is another minor route by which cytosolic free oligomannosides are produced.

Acetylglucosaminidase↗
PubMed1999

Identification and PCR-restriction fragment length polymorphism analysis of a variant of the Ibaraki virus from naturally infected cattle and aborted fetuses in Japan.

One hundred fourteen field isolates of the Ibaraki virus (IBAV), a member of the epizootic hemorrhagic disease virus serotype 2 (EHDV-2), were isolated from blood samples of affected and apparently healthy cattle and Culicoides biting midges and from blood samples of dams and internal organs of aborted fetuses during an outbreak of Ibaraki disease in the southern part of Japan in 1997. In this outbreak, 242 cattle showed typical symptoms of the disease, and several hundred dams had miscarriages or stillbirths. The viruses that induced typical Ibaraki disease and reproductive problems among cattle were identical and were antigenically closely related to but distinct from previous isolates of IBAV and EHDV-2. The virus was considered to be a putative agent of this outbreak. Reverse transcription-PCR based on segment 3 of the RNA genome of EHDV-2 and restriction fragment length polymorphism analysis of the PCR products were conducted to compare the genomes of the viruses. The results suggested that the virus isolated in 1997 was a variant of IBAV and might be exotic.

Abortion, Veterinary↗
PubMed1999

The utility of endoscopic ultrasonography and endoscopy in the endoscopic mucosal resection of early gastric cancer.

OBJECTIVE: To clarify the usefulness of endoscopic ultrasonography (EUS) and endoscopy in the endoscopic mucosal resection (EMR) of early gastric cancer. Patients/Methods-EMR was performed in 61 patients with early gastric cancer over the past five years. The accuracy of the assessment of the depth of cancerous invasion was studied in 49 patients who had EUS before EMR. Forty eight patients were treated with endoscopy alone; in these patients, EUS and endoscopic findings correlated with the clinical course. RESULTS: Forty six patients showed no changes in the submucosal layer or deeper structures on EUS. Pathologically these included 37 patients with mucosal cancer and nine with submucosal cancer showing very slight submucosal infiltration. Three patients showed diffuse low echo changes in the submucosal layer on EUS; pathologically, these included two with submucosal cancer and one with mucosal cancer with a peptic ulcer scar within the tumour focus. Of 48 patients receiving endoscopic treatment alone, 45 showed no tumour recurrence or evidence of metastases on EUS and endoscopy. Three cases of recurrence were observed. Two of these patients had a surgical gastrectomy, and one was re-treated endoscopically. In the former cases, the surgical results correlated well with assessment by EUS and endoscopy. In addition, the latter patient who was re-treated endoscopically after evaluation with EUS and endoscopy has so far had no recurrence. CONCLUSION: The combined use of EUS and endoscopy is effective in diagnosing the depth of cancerous invasion in patients undergoing EMR as well as in clarifying changes both within and between anatomic levels during follow up.

Aged↗
PubMed1999

New cyclization mechanism for squalene: a ring-expansion step for the five-membered C-ring intermediate in hopene biosynthesis.

Three triterpenes having the 6/6/5-fused tri- and 6/6/6/5-fused tetracyclic skeletons were isolated from an incubation mixture of the mutated F601A enzyme, these products being in accordance with a Markovnikov closure. Successful trapping of the tricyclic cationic intermediate by using the squalene analog having a highly nucleophilic hydroxyl group leads us to propose that the ring expansion process of the 5-membered C-ring is involved in the squalene cyclization cascade.

Amino Acid Substitution↗
PubMed1999

Revision laparoscopy for incarcerated hernia at a 5-mm trocar site following pediatric laparoscopic surgery.

We report the case of a 6-month-old female infant who developed post-operative bowel obstruction due to an incarcerated hernia through a 5-mm laparoscopic wound. The patient underwent laparoscopic Nissen fundoplication for gastroesophageal reflux. On day 6, she showed symptoms of ileus, and the diagnosis of a trocar wound hernia was made on day 13. The herniated intestine was reduced and the defective peritoneum and fascia were closed under relaparoscopic guidance, thus avoiding full-scale laparotomy. A trocar wound hernia causing early postoperative bowel obstruction is a rare complication, especially at 5-mm trocar puncture sites. Intraoperative dislodgment and reinsertion of working trocars may create fascial defects larger than the actual size of the trocar. All laparoscopic puncture wounds, even those <10 mm in size, should be closed at the fascial level in infants. Revision laparoscopy is considered preferable to manage trocar site complications in children.

Female↗
PubMed1999

Laparoscopic surgery assisted by a transvaginal approach.

We used laparoscopic surgery assisted by a transvaginal approach for gastrointestinal diseases. In the first case, a huge submucosal tumor enucleated laparoscopically from the minor curvature of the stomach was extracted through the vagina. In the second case, partial resection of the rectum to treat rectal endometriosis was performed laparoscopically with the assistance of manual handling inserted transvaginally. Although it can be applied only to female patients, especially to multipara, the vagina as an access point to the abdominal cavity can be widely used for various purposes in laparoscopic surgery.

Adult↗
PubMed1998

The solution structure of human endothelin-2 a 1H-NMR and CD study.

The solution structure of the vasoactive endogenous 21-amino-acid human endothelin-2 has been determined by NMR and CD techniques, in a mixed solvent of 100 mM aqueous acetic acid and 25% (by vol.) 1,1,1,3,3,3-hexafluoro-2-propanol. From NMR-derived restraints on upper limit distances and dihedral angles, distance geometry structures were calculated using the program DADAS90, and refined by simulated annealing in X-PLOR. The structure of endothelin-2 consists of an alpha-helix of residues 9 to 17, orientated anti-parallel to a short beta-strand of residues 1 to 3, linked together by a possible beta-turn type I of residues 5-8. These secondary structural elements are stabilised and positioned by two disulphide bonds between residues 1 and 15, and 3 and 11, respectively. The average root mean square deviation over residues 1-17 of 15 accepted low-energy conformers chosen to reflect the solution structure of endothelin-2, was 0.73 A for the backbone and 1.41 A for all heavy atoms. The data on endothelin-2 will be discussed and compared with what has been published on other endothelin/sarafotoxin peptides.

Amino Acid Sequence↗
PubMed1998

Aggressive non-Hodgkin's lymphoma after successful eradication of Helicobacter pylori and regression of gastric lymphoma of mucosa-associated lymphoid tissue.

A 57-year-old woman presented to our clinic with low-grade gastric lymphoma of mucosa-associated lymphoid tissue (stage IE) and Helicobacter pylori infection. She received a 2-week course of omeprazole and clarithromycin, resulting in eradication of H. pylori and histological disappearance of the lymphoma. However, 9 months later (May 1996), multiple mass lesions were found around the pancreas and hepato-duodenal ligament on abdominal computed tomography. Inguinal lymph node biopsy revealed aggressive nodal type B-cell non-Hodgkin's lymphoma, diffuse large cell type. She received chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone, but failed to achieve remission and died in December 1996. There was no evidence of recurrent gastric lymphoma. This case emphasizes the importance of performing follow-up examinations to detect other neoplasms in patients with gastric lymphoma of mucosa-associated lymphoid tissue.

Diagnosis, Differential↗
PubMed1998

Endoscopic resection of small duodenal carcinoid tumors with strip biopsy technique.

BACKGROUND: Most cases of duodenal carcinoid have conventionally been treated by surgical resection. The aim of our study was to explore the feasibility of endoscopic resection in small duodenal carcinoids. METHODS: The study population consisted of seven patients with small duodenal carcinoids. The diagnosis was confirmed by preoperative biopsies. The depth of tumor invasion was evaluated by endosonography. RESULTS: The carcinoid was detected by endosonography in all cases. Size ranged ultrasonographically from 1.5 mm to 7 mm. Tumor invasion was confined to the submucosa in all patients. Endoscopic resection was performed with the strip biopsy technique using a two-channel endoscope. In six patients, the specimens were resected without severe complications. Five of them were confirmed histologically to be typical carcinoids. In one patient, carcinoid was not detected histologically in the specimen. In the remaining patient, a perforation occurred. However, the huge ulcer was managed conservatively. Follow-up endoscopy revealed no evidence of recurrent or residual tumor in any patient. CONCLUSION: Small duodenal carcinoids confined to the submucosa can be resected endoscopically and preoperative endosonography is necessary for the determination of endoscopic resectability.

Aged↗
PubMed1998

Limitations of percutaneous transhepatic cholangioscopy for the diagnosis of the intramural extension of bile duct carcinoma.

BACKGROUND AND STUDY AIMS: Vascular dilatation seen on percutaneous transhepatic cholangioscopy (PTCS) is diagnostic of intramural invasive carcinoma of the bile duct, but the limitations of the technique, including biopsy, for the diagnosis of intramural extension of bile duct carcinoma have not to our knowledge been investigated before. The aims of the present study were to estimate the thickness of the specimens of bile duct wall taken by biopsy, to assess the sensitivity of PTCS for detecting intramural invasive carcinoma, and to identify the characteristics of the intramural extension of bile duct carcinoma associated with vascular dilatation. PATIENTS AND METHODS: A total of 135 biopsy, and 16 surgical specimens obtained from 25 bile duct carcinomas were examined for: the thickness of the biopsy specimens and of the mucosa and combined mucosal-fibromuscular layers in the resected common bile ducts and common hepatic ducts; the presence of muscular and neural bundles in the biopsy specimens; the number of invasive carcinomas in the biopsy specimens that had been taken from stenosed regions; and the relation between intramural extension of invasive carcinoma and vascular dilatation. RESULTS: The mean thickness of the biopsy specimens did not differ from the mean thickness of the mucosa in the resected specimens, but was significantly lower than that of the combined mucosa and fibromuscular layer. Muscular bundles were included in only 13 (14%) of the biopsy specimens, and there were no neural bundles. Carcinomas and invasive carcinomas were diagnosed histologically from the biopsy specimen in 96% and 91% of the cases, respectively. The sensitivity of a single biopsy for diagnosis for invasive carcinoma in stenosed regions was 62%, almost the same as the sensitivity in non-stenosed regions with vascular dilatation (68%). On histologic examination of 16 resected specimens, the sensitivity and specificity of vascular dilatation as a marker of the intramural extension of an invasive carcinoma were 39% and 100%, respectively, and this was significantly more common in invasive carcinomas that were invading the mucosa beyond the adventitia than in those limited to the adventitia. CONCLUSION: Histologic examinations of specimens obtained by PTCS-guided biopsy can detect invasive carcinoma in only the superficial layers of the bile duct, such as the mucosa and the shallowest fibromuscular layer. Multiple specimens are needed for the diagnosis of invasive carcinoma because the sensitivity of examination of a single specimen for detecting invasive carcinoma is low. Vascular dilatation is characteristic of carcinoma that is invading the mucosa beyond the adventitia, so the diagnosis of intramural extension of bile duct carcinoma limited to the adventitia, particularly if it has spread to the deeper fibromuscular layer and the adventitia, is difficult to make by PTCS.

Adult↗
PubMed1998

Laparoscopic ovarian cystectomy using double balloon catheter: a new technical application.

In the present study, a modified application of the surgical instrument with double balloon is described in the ovarian cystectomy procedure. This technique has been proved effective and safe especially in removing chocolate-like cystoma. This new instrument, which we originally designed, has two balloons at the tip of the catheter. After a cyst is punctured, the inner and outer balloons are inflated to fix the cyst well. After fixing the cyst with two balloons, the internal needle of the instrument can be removed. This catheter, named the SAND balloon catheter, is advantageous in laparoscopic ovarian cystectomy.

Journal Article↗
PubMed1998

Thoracoscopic parasternal lymph node dissection for the staging of breast cancer.

With the advent of advanced thoracoscopic techniques, new applications have been expanding their roles in thoracic surgery. The aim of this paper is to introduce our new thoracoscopic approach in performing parasternal lymph node dissection of advanced breast cancer for its staging. This technique does not need the removal of any costal cartilage which is usually done in the conventional classical technique after radical mastectomy. Thoracoscopic procedure, in which wide and complete parasternal lymph node dissection is done, is minimally invasive and easy to perform. Therefore, the thoracoscopic technique may be a suitable alternative to the conventional approach in the future.

Journal Article↗
PubMed1998

[Value of MR cholangiography in the diagnosis of pancreatic diseases compared with endoscopic retrograde cholangiopancreatography].

PURPOSE: To compare magnetic resonance cholangiography (MRCP) with endoscopic retrograde cholangiography (ERCP) in the diagnosis of pancreatic diseases. METHODS: The authors retrospectively reviewed MRCP and ERCP images obtained in 56 patients with pancreatic diseases and 192 controls. Detectability of the pancreatic duct and its branches and diagnostic usefullness were evaluated. RESULTS: MRCP was successful in almost all the patients without ascitic fluid or ileus. Findings of the main pancreatic ducts (i.e., dilation, stenosis and obstruction) were similarly demonstrated by ERCP and MRCP. The degree of ductal narrowing tends to be overestimated with MRCP. CONCLUSION: MRCP appears to be less invasive than ERCP. MRCP could provide sufficient information and play a complementary role in the diagnosis of pancreatic diseases.

Adult↗
PubMed1997

Special folding pathway to tetramer only through the micelle state of the corticotropin-releasing factor.

The ovine corticotropin-releasing factor (CRF), a peptide hormone of 41 residues stimulating the secretion of adrenocorticotropic hormone, was thermodynamically investigated. By means of size exclusion chromatography and/or ultrafiltration, the CRF solution could be separated into random coil monomers and highly alpha-helical tetramers, which seem to have amphipathic helix bundle structure. Circular dichroism measurements along with diluting or concentrating the CRF solution revealed that there exists the micelle state above the concentration of 0.1 mM, which would be the critical micelle concentration (cmc). The micelle state was also proved by binding ability for 8-anilino-1-naphthalenesulfonate and endothermic change by dilution across the cmc. The tetramer showed the cooperative thermal transition at about 55 degrees C in the buffer solution (pH 7.5), so that it would have native-protein-like folding. On the other hand, the micelle undergoes gradual change to dissociated state by heating, regardless of the similar alpha-helicity to the tetramer. Above the cmc the equilibrium between the tetramer and the micelle takes place as well as that between the monomer and the micelle. Whereas, the direct conversion between the tetramer and the monomer scarcely occurred below the cmc. The titration experiment with 2,2,2-trifluoroethanol (TFE) revealed that the cmc decreases with increasing the concentration of TFE. This tendency is the same as that of general surfactants. Most of experimental results can be well explained by this three-phase model involving the monomer, the tetramer, and the micelle. The lack of the equilibrium between the monomer and the tetramer indicates that the folding pathway of the tetramer is the transformation only through the micelle state and not from the monomer. This pathway resembles the collapse model among the phenomenological models for thermodynamic protein folding. By the mathematical consideration for the dissociation of micelle, we have demonstrated that the expected content of undegradable k-mer is 2/(k + 1), which agreed well with the observed tetramer content of CRF (40%).

Anilino Naphthalenesulfonates↗
PubMed1997

Abnormal expansion of peripheral gamma delta T cells in patients with neurologic disorders.

The proportions and the variable region usages of peripheral gamma delta T cells were investigated in 205 patients with various neurologic disorders. Flow cytometric analysis was performed with monoclonal antibodies against C delta, V delta 1, V delta 2. V delta 1-J delta 1/J delta 2, and V gamma II (9) epitopes. Further analysis was carried out with reverse transcription-polymerase chain reaction (RT-PCR) using variable region-specific primers. The proportion of gamma delta T cells in 33 patients with cerebral palsy (CP) (mean +/- SD; 11.1 +/- 11.0%) was significantly higher than that in 35 normal controls (5.6 +/- 2.6%) (p < .01). Of 205 patients, persistent gamma delta T cell expansion over 15% was observed in 15 patients (M/F = 13/2). Nine of these 15 were patients with CP. Six of the 9 with CP had neither perinatal nor postnatal events related to the neurologic abnormalities. None of the 9 with CP had active infections or autoimmune disorders that could induce gamma delta T cell expansion. Of the 15, 13 had V gamma II/V delta 2-dominant expansion and 2 showed V delta 1-dominant expansion. Unusual expansions of V delta 4 and V delta 6, which were not usually found in peripheral blood, were detected by RT-PCR in one case with CP and V delta 1-dominant expansion. This study showed subclinical immunologic abnormalities with marked and persistent gamma delta T cell expansion in patients with neurologic disorders, especially CP. These results might indicate the existence of neuroimmunologic disorder(s).

Adolescent↗
PubMed1997

Thoracoscopic surgery combined with a supraclavicular approach for removing superior mediastinal tumor.

This report introduces our new technique of thoracoscopic surgery combined with a supraclavicular approach for removing superior mediastinal tumor. A 68-year-old woman noticed a tumor palpable in the left supraclavicular fossa. The patient had no pain around the neck and shoulder. A radio-opaque shadow 6 cm in diameter was detected in her left apical lung field on chest roentgenogram. Chest CT and MRI showed that the tumor was located in the superior mediastinum, extending up to the thoracic inlet, and there was no invasion of the surroundings. At first, a thoracoscopic examination was performed to assess the possibility of the excision. After dissecting the tumor from the mediastinal tissue and the first costovertebrae as far as possible by thoracoscopic surgery, a supraclavicular approach was used to enter the thoracic cavity. Complete resection of the tumor was successfully performed by thoracoscopic surgery combined with a supraclavicular approach. The tumor was removed in a plastic bag through the supraclavicular defect. Postoperative histopathology revealed that the tumor was a benign neurogenic one. A satisfactory follow-up of 5 postoperative days was observed without any complications, and the patient was discharged. The procedure was safe, easy, and minimally invasive to perform. Moreover, the supraclavicular approach could be used to add trocar port if needed.

Aged↗