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Biomedical subjects

K Yamaguchi

Publications and source records attributed to K Yamaguchi.

At least 487 records · Page 27Linked to original sources
PubMed1999

[Susceptibilities of Enterococcus faecium, PRSP and MRSA to RP59500 and their correlations with those to other drugs].

Investigations on emergence of vancomycin-resistant Enterococcus faecium (VREF) which has recently been attracting attention, especially in the Western countries, have been conducted in Japan. A total of 1,239 isolates of E. faecium were collected from 19 institutions during the period of April 1995 and June 1996, in the purpose of evaluating susceptibilities to variety of antimicrobial agents, including RP59500 and vancomycin (VCM), and detecting vancomycin-resistant genes (van genes). Susceptibilities of penicillin-resistant Streptococcus pneumoniae (PRSP) and methicillin-resistant Staphylococcus aureus (MRSA) were also studied. As a result, 2 isolates of E. faecium were found to be moderately resistant to VCM showing MIC of 8 micrograms/ml though the final identification in species level and the detection of van genes by PCR method have not been completed. On the other hand there detected no MRSA nor PRSP showing moderately resistant or resistant to VCM. It was concluded that RP59500 and VCM possessed favorable activity against clinically isolated E. faecium, PRSP and MRSA. Among other species of enterococci, moderately resistant strains to VCM showing MIC of 8 micrograms/ml were detected; 10 isolates of E. gallinarum, 4 of E. casseliflavus and 2 of E. flavescens. In those isolates, vanC1 and vanC2 were detected by PCR, and vanB was also detected in a isolates of E. gallinarum simultaneously.

Anti-Bacterial Agents↗
PubMed1999

[Simulation study on parent artery occlusion therapy for basilar head giant aneurysms: hemodynamic efficacy of additional bypass on enhancing aneurysmal thrombosis].

Parent artery occlusion therapy has been used as an alternative for directly untreatable basilar head giant aneurysms. However, some aneurysms still require additional technique to further induce intraaneurysmal stagnation and thrombosis. Using a hydraulic model, half-life of the dye in the model aneurysm was measured as an index of the intraaneurysmal stagnation. The ratio of diameters (D1, D2) of the two posterior communicating arteries (PCom) is defined as diameter ratio (DR) (D1/D2, D1 < D2). Occlusion therapy was simulated in 4 different sites. The most distal site was at the distal BA (Type A) and the most proximal site at the bilateral VA (Type D). The additional technique investigated was bypass placement to the P2 segment of the posterior cerebral artery (PCA) on the smaller PCom side. The half-life was 2.5 +/- 0.2 (mean +/- 2SD) sec before occlusion. Occlusion therapy significantly increased the half-life depending on the occlusion site and DR values with the maximum values of infinite in Type A and 25 sec in Type D. Placement of the bypass decreased the tangential flow volume to the aneurysmal neck, and increased the time markedly in Types A and B, considerably in Type C and slightly in Type D. Parent artery occlusion therapy has been considered less beneficial for patients with a diameter ratio of less than 0.70 since aneurysmal stagnation depends on the diameter ratio. Bypass placement additional to the occlusion therapy is very useful in enhancing the aneurysmal stagnation, which would make those patients indicated for the therapy.

Basilar Artery↗
PubMed1999

[The calculated reference value of the tubular extraction rate in infants and children: an attempt to use a new regression equation].

This study was designed to investigate the empirical tubular extraction rate (TER) of the normal renal function in childhood and then propose a new equation to obtain TER theoretically. The empirical TER was calculated using Russell's method for determination of single-sample plasma clearance and 99mTc-MAG3 in 40 patients with renal disease younger than 10 years of age who were classified as having normal renal function using diagnostic criteria defined by the Paediatric Task Group of EANM. First, we investigated the relationships of the empirical value of absolute TER to age, body weight, body surface area (BSA) and distribution volume. Next we investigated the relationships of the empirical value of BSA corrected TER to age, body weight, BSA and distribution volume. Linear relationship was indicated between the absolute TER and each body dimensional factors, especially regarding to BSA, its correlation coefficient was 0.90 (p value). The BSA-corrected TER showed a logarithmic relationship with BSA, but linear regression did not show any significant correlation. Therefore, it was thought that the normal value of TER could be calculated theoretically using the body surface area, and here we proposed the following linear regression equation: Theoretical TER (ml/min/1.73 m2) = (-39.8 + 257.2 x BSA)/BSA/1.73 The theoretical TER could be one of the reference values of the renal function in the period of the renal maturation.

Body Surface Area↗
PubMed1999

[Two cases of duodenal tuberculosis].

The present study described 2 cases of patients with duodenal tuberculosis. Case 1 was a 55 year-old Japanese male patient with pulmonary tuberculosis and past medical history of subtotal gastrectomy (Billroth II reconstruction). Tubercle bacilli were positive both on smear and culture from his sputum and feces. Because of complaining right hypochondralgia, upper gastrointestinal endoscopy was performed and revealed multiple ringed ulcers in the afferent limb of duodenum. Histopathological study of biopsy specimen demonstrated granulomatous inflammation as well as acid-fast bacilli confirmed by Ziehl-Neelsen staining. Tissue culture was positive for M. tuberculosis. Colonic tuberculosis was demonstrated by barium enema. Case 2 was a 45 year-old male patient with pulmonary tuberculosis in association with severe uncontrolled diabetes mellitus. Sputum polymerase chain reaction test was positive for M. tuberculosis. Granulomatous inflammation and positive acid-fast bacilli in biopsy specimen obtained from ulcers in the descending portion of the duodenum made a diagnosis of duodenal tuberculosis. No other intestinal tuberculous lesion was recognized. Since 1988, 11 cases of duodenal tuberculosis including the presented two cases have been reported in Japan. Most of the recent cases had tuberculous lesions in the descending portion of the duodenum and were diagnosed as duodenal tuberculosis by endoscopic examinations, while the majority of the cases reported before 1987 had tuberculosis in the more distant portions of the duodenum and were diagnosed mainly by surgical procedures.

Duodenal Diseases↗
PubMed1999

Evaluation of the substantia nigra in patients with Parkinsonian syndrome accomplished using multishot diffusion-weighted MR imaging.

BACKGROUND AND PURPOSE: Although it is important to evaluate the substantia nigra in patients with parkinsonian syndrome, it is difficult to depict its anatomy, even by MR imaging. Using anatomic studies of the direction of nerve fibers around the substantia nigra, we attempted to depict this entity with multishot diffusion-weighted MR imaging to evaluate its topographic changes in patients with Parkinson's disease and secondary parkinsonism. METHODS: We measured the substantia nigra on 72 diffusion-weighted axial MR images obtained in 36 healthy control subjects, on 47 images obtained in 25 patients with Parkinson's disease, and on 10 images obtained in five patients with secondary parkinsonism. We considered the width of the minor axis of the substantia nigra as its "thickness," which appeared as a crescent-shaped region in the midbrain. RESULTS: Diffusion-weighted imaging portrayed the substantia nigra distinctly better than did T2-weighted imaging, because the surrounding white matter appeared as an area of high signal intensity. The mean (+/- SD) thickness values of the substantia nigra were 5.1+/-0.89 mm in control subjects, 4.8+/-0.75 mm in patients with Parkinson's disease, and 3.4+/-0.53 mm in patients with secondary parkinsonism. CONCLUSION: Multishot diffusion-weighted imaging is a better imaging technique than T2-weighted imaging for demonstrating a change in size of the substantia nigra in vivo. The substantia nigra is not reduced in size in patients with Parkinson's disease, but it is reduced in patients with secondary parkinsonism.

Adult↗
PubMed1999

Powerful activation of skeletal muscle actomyosin ATPase by goniodomin A is highly sensitive to troponin/tropomyosin complex.

Goniodomin A has been shown to cause the conformational change of actin to modify actomyosin ATPase activity. Goniodomin A induced a potent stimulation of the actomyosin ATPase activities of the actin-myosin reconstituted system and natural actomyosin in the range of 10(-8) to 10(-7) M. When the concentration was increased above 10(-7) M, actomyosin ATPase activity was decreased. Interestingly, the troponin/tropomyosin complex caused a concentration-dependent inhibition of the goniodomin A-induced stimulation of actomyosin ATPase activity. In the presence of a high concentration of the troponin/tropomyosin complex, goniodomin A decreased actomyosin ATPase activity in a concentration-dependent manner. The enhancement of the ATPase activity of troponin/tropomyosin-free natural actomyosin by goniodomin A was larger than that obtained with natural actomyosin. Goniodomin A at lower concentrations enhanced the superprecipitation of natural actomyosin but decreased it at higher concentrations. The ATPase activity of skeletal muscle myofibrils and the contractile response of skinned fibers to Ca(2+) were never activated and were decreased by this compound, suggesting an inhibition by the troponin/tropomyosin complex. In the far ultraviolet circular dichroism, goniodomin A above 10(-8) M increased the negative ellipticity at 220 nm, suggesting an increase in the alpha-helical content of actin. These results suggest that goniodomin A increases and decreases actomyosin ATPase activity, probably through the stimulatory and inhibitory sites on actin, respectively. It is also suggested that the troponin/tropomyosin complex binds to actin to inhibit the goniodomin A-induced enhancement of actomyosin ATPase activity, probably by affecting the stimulatory site on the molecule.

Actins↗
PubMed1999

[Two cases of sporadic juvenile Parkinson's disease caused by homozygous deletion of Parkin gene].

Parkin gene, which is one of the causes of familial Parkinson's disease, was cloned in 1998, and it was found that mutations of this gene induces familial Parkinson's disease of autosomal recessive form (AR-JP). Clinical studies have revealed that almost cases of AR-JP are consanguineous or hereditary. However, AR-JP may also be caused by marriage between two carriers. We therefore investigated the existence of a homozygous deletion in the parkin gene in 10 patients with juvenile Parkinson's disease with the onset of age younger than 40 years without consanguinity or heredity. A large delection of the gene was found in 2 of the 10 patients with sporadic Parkinson's disease, and both of these deletion were exon 4. The present study clearly suggests that juvenile Parkinson's disease in Japan may be caused by abnormalities in parkin gene regardless of family history or consanguinity.

Age of Onset↗
PubMed1999

[Isoferritin].

Explore the source record for details and available documents.

Biomarkers, Tumor↗
PubMed1999

Convenient murine pneumoperitoneal model for the study of laparoscopic cancer surgery.

To investigate the effects of laparoscopic surgery on the progression of cancers, it is necessary to establish a reliable and economical animal model. We describe a convenient murine pneumoperitoneal model for the study of laparoscopic cancer surgery. Under anesthesia using diethyl ether, peritoneal cavity was insufflated with gas through an intravenous catheter placed in the left lower quadrant. Syringe pump was used for continuous gas insufflation, and intraperitoneal pressure was measured. Intraperitoneal pressure increased and reached 10 cm H2O when 15 mL of CO2 gas was injected, but fell to 1 cm H2O 5 min after stopping the injection. When the continuous flow was adjusted by syringe pump between 20 and 160 mL/hour, intraperitoneal pressure was easily maintained at 8 cm H2O for >60 min. We believe that this murine model for pneumoperitoneum may be useful for the study of laparoscopic cancer surgery.

Animals↗
PubMed1999

Positive washing cytology in patients with pancreatic cancer indicates a contraindication of pancreatectomy.

BACKGROUND: Although peritoneal washing cytology has been widely used in the field of gynecology, it has not been performed so frequently in patients with pancreatic cancer. Only a few papers have reported surgical implications of peritoneal washing cytology. MATERIALS AND METHODS: We reviewed results of peritoneal washing cytology performed immediately after laparotomy in 50 Japanese patients with pancreatic cancer. The 50 patients were divided into two groups according to the results of cytology. Clinicopathological findings were compared between these two groups. RESULTS: Cytology of peritoneal washing was positive in 13 (26%) of the 50 patients. Nine of the 13 patients had no visible peritoneal dissemination. There were no significant differences regarding the age, tumor size and serum level of the carcinoembryonic antigen. Moderately to poorly differentiated adenocarcinoma and perineural invasion (ne3) and lymphatic permeation (ly3) of marked degree were more frequent in the positive group than in the negative group (p < 0.01). The survival curve of the 37 patients with negative cytology was significantly better than that of the 13 with positive cytology (p < 0.01). Four of 13 patients with positive cytology underwent a potentially curative resection but died within 12 months. Three of these four patients died of peritonitis carcinomatosa with massive malignant ascites and one died of local recurrence. CONCLUSIONS: Positive peritoneal washing cytology is not rare in patients with pancreatic cancer and indicates a contraindication of pancreatectomy.

Adenocarcinoma↗
PubMed1998

RANK is the essential signaling receptor for osteoclast differentiation factor in osteoclastogenesis.

Osteoclast differentiation factor (ODF) is a ligand for osteoclastogenesis-inhibitory factor/osteoprotegerin (OCIF/OPG), and mediates an essential signal for osteoclastogenesis. Soluble-form ODF binds directly to osteoclast progenitors, suggesting the presence of a membrane-bound receptor for ODF (ODFR) on the cells. To understand the ODF-mediated signal transduction mechanism in osteoclastogenesis, we molecularly cloned ODFR from a mouse macrophage-like osteoclast progenitor cell line, C7. Nucleotide sequence analysis revealed that ODFR is identical to RANK, a recently identified member of the tumor necrosis factor receptor (TNFR) family, which is involved in the regulation of dendritic cell function. A polyclonal antibody against the extracellular domain of RANK induced osteoclastogenesis in the presence of macrophage colony-stimulating factor (M-CSF). In contrast, both a genetically engineered soluble RANK and Fab fragment of the antibody blocked the binding of ODF to RANK and ODF-mediated osteoclastogenesis. These results indicate that RANK is the signaling receptor essential for ODF-mediated osteoclastogenesis.

Animals↗
PubMed1998

A gas chromatographic method for the sugar analysis of 3,6-anhydrogalactose-containing algal galactans.

This paper describes a new gas chromatographic method for the compositional analysis of algal galactans containing 3,6-anhydrogalactose, which is readily destroyed in usual acid hydrolysis and methanolysis. Mercaptolysis of galactans was carried out under an anhydrous condition using the newly developed solvent system, an ethanethiolic HCl solution which had been prepared by blowing dry HCl gas into ethanethiol. By heating galactans in 0.5 N HCl/ethanethiol at 60 degrees C for 12 h, component sugars including 3,6-anhydrogalactose were released quantitatively as their diethyl mercaptals. The monosaccharide diethyl mercaptals were trimethylsilylated and analyzed by gas-liquid chromatography. Each component monosaccharide was detected as a single peak since neither anomeric nor structural isomers can be produced by mercaptolysis. Furthermore, the solvent system was improved by the addition of methanol in a ratio (2/1, v/v) of ethanethiol to methanol. Heating of galactans at 60 degrees C in 0.5 N HCl/[ethanethiol:methanol (2/1, v/v)] released more rapidly and quantitatively monosaccharide diethyl mercaptals without any formation of monosaccharide methyl glycosides. The present method was applicable to not only algal galactans but also algal powders.

Carbohydrate Sequence↗
PubMed1998

Calcium-induced exposure of a hydrophobic surface of mouse ALG-2, which is a member of the penta-EF-hand protein family.

ALG-2 is a 22 kDa EF-hand type Ca2+-binding protein associated with lymphocyte apoptosis. Comparison of the primary structure of ALG-2 with those of EF-hand type proteins revealed that it belongs to the penta-EF-hand (PEF) protein family including the small subunit of calpain. We established a convenient method for the purification of the recombinant mouse ALG-2 expressed in Escherichia coli. The recombinant protein was first pelleted from a lysate in the absence of a Ca2+-chelator, and then extracted with buffer containing EDTA/EGTA followed by purification by conventional column chromatographies. Estimation of the molecular mass by gel filtration suggested that the recombinant ALG-2 occurred as a monomeric form. Ca2+-dependent precipitation was blocked by inclusion of non-ionic detergent Triton X-100, suggesting hydrophobic self-aggregation at high concentrations of the protein. The N-terminal deletion mutant lacking the hydrophobic non-PEF region was found to be more soluble than the wild type in the presence of Ca2+. Analysis using a fluorescent hydrophobicity probe indicated that ALG-2 exposed a hydrophobic surface in a Ca2+-concentration dependent manner, the half-maximal effect occurring at approximately 6 microM. Mg2+ was not effective for the conformational change. On Western blotting, ALG-2 was detected in particulate fractions from cultured mammalian cells, suggesting the association of the protein with macromolecules in the cells.

Amino Acid Sequence↗
PubMed1998

High-performance liquid chromatographic determination of erdosteine and its optical active metabolite utilizing a fluorescent chiral tagging reagent, R-(-)-4-(N,N-dimethylamiosulfonyl)-7-(3-aminopyrrolidin-1-yl)-2 ,1,3-benzoxadiazole.

Chiral separation of racemic M1 metabolized from erdosteine was investigated by reversed-phase chromatography. The sensitive determination of M1 and erdosteine with UV detection was difficult because of their low absorptivity in the effective wavelength region. To improve the sensitivity and separatability, one thiol and two carboxyl groups in the M1 structure were labelled with DBD-F and R-(-)-DBD-APy, respectively. Non-fluorescent DBD-F quantitatively reacted with thiol in M1 at room temperature for 30 min in borate buffer (pH 9.3) to produce the fluorescent derivative. On the other hand, the labelling of two carboxyls was carried out with a chiral fluorescent reagent, R-(-)-DBD-APy, in acetonitrile containing DPPA. The derivatives corresponding to a pair of the enantiomers were completely separated with water-acetonitrile containing 0.1% TFA as the mobile phase by an ODS column. Erdosteine with a carboxyl group was also labelled with R-(-)-DBD-APy and separated together with M1 derivatives. The detection limits (S/N=3) of erdosteine and M1 were 0.37 and 0.22 pmol, respectively. The proposed derivatization and separation methods were applied to simultaneous determination of racemic M1 and erdosteine in rat plasma after administration of erdosteine. The amounts of both enantiomers of M1 were essentially the same in oral and intravenous administrations. In contrast, total amounts (reduced-form and oxidized-form) of S-(-)-M1 in rat plasma were higher than those of R(+)-M1 in both administrations.

Animals↗