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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 235 records · Page 13Linked to original sources
PubMed1998

[Resistance to macrolide antibiotics found in methicillin-resistant Japanese clinical isolates of Staphylococcus aureus in 1996].

Minimum inhibitory concentrations (MICs) of erythromycin, clarithromycin, roxithromycin, oleandomycin, triacetyloleandomycin, azithromycin, josamycin and midecamycin were investigated using 200 strains of methicillin-resistant Staphylococcus aureus (MRSA) clinically isolated in Japan during 1996. The results show that the MRSAs could be classified into five groups according to MIC patterns to various macrolides and that more than 88% of the strains used were highly-resistant to all macrolides tested. It was found that 9.0% of the strains examined showed a unique MIC pattern different to that of macrolide-lincosamide-streptogramin B antibiotic resistance type. This group was found to be highly resistant to 14-membered but susceptible to 16-membered macrolides. The resistance induction by erythromycin or oleandomycin was observed to increase for clarithromycin and roxithromycin resistances in a part of strains used. On the other hand, for azithromycin, such induction was not observed.

Anti-Bacterial Agents↗
PubMed1998

Salt-sensitive aortic aneurysm and rupture in hypertensive transgenic mice that overproduce angiotensin II.

We studied the effect of excessive salt intake on vascular lesion development in hypertensive transgenic mice that overproduce angiotensin II, ie, Tsukuba hypertensive mice (THM). At 6 weeks of age, THM and C57BL/6J (controls) were given either 1% sodium chloride ("salt-loaded") drinking water or tap water for 30 days. Salt-loaded THM, but not controls, suffered frequent thoracic or abdominal cavity hemorrhage. THM mortality after 7 days of salt loading was 23%; after 30 days of salt loading, it rose to 67%. Hemorrhaging occurred due to the development of aortic aneurysm and rupture at the aortic arch and aorta near the renal arteries. Vascular lesions progressed with structural degeneration of the aortic media. Electronmicroscopic analysis revealed that intact THM already exhibited vascular remodeling consisting of vascular smooth muscle cells (VSMCs) with developed organelles and an increased extracellular matrix. Salt-loaded THM suffered aggravated vascular hypertrophy and vascular structure destruction by plasma material invasion, necrosis of VSMCs possessing extremely swollen cytoplasm and abundant organelles, and interlamellar bleeding, resulting in aortic aneurysm and eventual rupture. Interestingly, blood pressure levels and heart rates in salt-loaded THM did not differ significantly from those of controls; plasma renin activity between drinking regimens was also comparable between the two groups. Drinking volume and the concentration of atrial natriuretic peptide (ANP) in plasma, however, were significantly higher in salt-loaded THM than in intact THM. In addition to aneurysm localization, the findings regarding drinking volume and plasma ANP suggest that aortic aneurysm and rupture in salt-loaded THM occurred as the result of an unknown mechanical stress, other than blood pressure, on the aortic wall. High salt ingestion is involved in the development of thoracic and abdominal aortic aneurysm in the presence of hypertension in the activated renin-angiotensin system. THM should therefore serve as a useful animal model for studying the pathogenesis of aortic aneurysm accompanied by hypertension.

Angiotensin II↗
PubMed1998

Appearance of fosfomycin resistant Rahnella aquatilis clinically isolated in Japan.

Among recent clinical isolates in Japan, strain CU264 was discovered which formed unusual colonies. This strain was identified as Rahnella aquatilis which is usually found in water. The antibiotic susceptibilities against tetracycline, carbenicillin, chloramphenicol, streptomycin, kanamycin, gentamicin, sulphonamide, neomycin, fosfomycin, rifampicin, norfloxacin and nalidixic acid, were investigated. The result demonstrated that the strain was highly resistant to fosfomycin only. It was further shown that this resistance was transmissible with low frequency to Serratia marcescens whereas it was not transmissible to Escherichia coli.

Anti-Bacterial Agents↗
PubMed1998

[Miliary tuberculosis associated with subcutaneous tuberculous abscess].

A 62-year-old woman was admitted because of a tumor on her right thigh, fever, generalized lymphadenopathy, and diffuse nodular shadows on chest X-ray films. She was given a diagnosis of miliary tuberculosis based on the findings of a cervical lymph-node biopsy and a broncho-alveolar lavage. Acute respiratory failure and disseminated intravascular coagulation developed, but resolved after the start of anti-tuberculous therapy. The tumor on the right thigh was diagnosed as a subcutaneous tuberculous abscess because tuberculous bacilli were detected in tumor tissue samples obtained by aspiration. The patient's fever disappeared and the abnormal shadows on her chest X-ray films receded significantly after drainage of the subcutaneous abscess. These findings suggested that miliary tuberculosis was associated with the subcutaneous tuberculous abscess in this case.

Abscess↗
PubMed1997

Reduced blood accumulation of biotinylated monoclonal antibody A7 after the subsequent administration of avidin.

Clear immunoscintigraphy with radiolabeled monoclonal antibodies (MAbs) requires a high tumor tissue/blood ratio of radioactivity. In this study, we attempted to obtain a high tumor tissue/blood ratio by the active removal of radiolabeled MAb from the circulation, using the avidin-biotin system. Biotinylated 125I-labeled MAb A7 was injected intravenously into nude mice bearing a human colon cancer (WiDr) xenograft. Avidin was injected 24 h later. The tumor tissue/blood ratio of radioactivity was almost four times that of controls. These results suggest that biotinylated 125I-labeled MAb A7 and avidin are potentially useful for the rapid immunodetection of human colon cancer.

Animals↗
PubMed1997

C-Myc expression and its role in patients with chronic aortic regurgitation.

BACKGROUND: Proto-oncogenes have been implicated in the pathogenesis of gene-mediated myocardial remodeling. In the human heart, however, it has not been clarified whether these proto-oncogenes are related to contractile impairment and structural alteration of the myocardium. The present study is designed to investigate the relationship between the c-Myc protein expression in the myocardium and the myocardial contractile dysfunction in patients with chronic aortic regurgitation who underwent indicated for aortic valve replacement. METHODS AND RESULTS: Twelve patients (11 males and one female) with an average age of 55 years who underwent aortic valve replacement for isolated chronic aortic regurgitation were studied. The preoperative New York Heart Association class was II in four patients and III in eight. Ejection fraction, end-systolic volume index, end-systolic stress (Mirsky's form), and mass index of the left ventricle before surgery were 47+/-13%, 93+/-37 mL/m2, 223.2+/-44.4 Kdyn/cm2, and 210+/-38 g/m2, respectively. A left ventricular endomyocardial biopsy was performed to assess the myocardial cell diameter, fibrous content, and c-Myc protein expression in the myocardium. Cell diameter and fibrous content were significantly higher than those in five normal controls. C-Myc was detected in 9 of 12 present patients but in none of the normal controls. The degree of c-Myc expression had significant positive correlations with ejection fraction (r=0.93; P<.01) and end-systolic stress/end-systolic volume index (r=0.96; P<.01) and significant negative correlations with end-systolic volume index (r=-0.90; P<.01), cell diameter (r=-0.97; P<.01), and fibrous content (r=-0.92; P<.01), which suggested that the degree of c-Myc expression may have a significant negative correlation with myocardial contractility and myocardial hypertrophy. CONCLUSIONS: C-Myc expression may be related to the pathogenesis of myocardial remodeling in patients with chronic aortic regurgitation.

Adult↗
PubMed1997

Are pyridoxal and fluorescein probes in lysine residues of alpha-chain in Na+,K(+)-ATPase sensing ATP binding?

Na+,K(+)-ATPase preparations from pig kidneys were treated with 50 microM pyridoxal 5'-diphospho-5'-adenosine (AP2PL) in the presence of NaCl. The resulting preparations contained 0.5 mol of the AP2PL probe at the Lys-480/mol alpha-chain. This modification reduced both Na+,K(+)-ATPase activity and the amount of Na(+)-dependent phosphoenzyme from ATP to around 50% but not that from acetyl phosphate (AcP). The addition of 1 mM AcP to the modified enzyme in the presence of Mg2+ and Na+ induced phosphorylation (3.0/s) followed by an AP2PL fluorescence increase (1.2/s). The addition of 10 microM ATP instead of AcP induced rapid phosphorylation (28/s) followed by a slow increase in fluorescence (1.0/s). When modified enzyme preparations were treated with fluorescein 5'-isothiocyanate (FITC), the phosphorylation capacity from ATP was reduced to around 5% with little influence on either the AP2PL fluorescence change by ATP or phosphorylation from AcP. The addition of increasing concentrations of ATP with 160 mM NaCl to the K(+)-bound AP2PL-FITC-labeled enzyme showed different rates for each fluorescence change and different affinities for ATP of the changes. These data and others indicate that the AP2PL probe at Lys-480 can monitor ATP binding to high- and low-affinity sites and suggest the simultaneous presence of two different low-affinity sites for ATP detected by an AP2PL probe at Lys-480 and an FITC probe at Lys-501.

Adenosine Diphosphate↗
PubMed1997

Stopped-flow kinetic investigations of conformational changes of pig kidney Na+,K+-ATPase.

The kinetics of Na+-dependent partial reactions of the Na+,K+-ATPase were investigated via the stopped-flow technique using the fluorescent labels RH421 and BIPM. After the enzyme is mixed with MgATP, both labels give almost identical kinetic responses. Under the chosen experimental conditions two exponential time functions are necessary to fit the data. The dominant fast phase, 1/tau1 approximately 180 s-1 (saturating [ATP] and [Na+], pH 7.4 and 24 degrees C), is attributed to phosphorylation of the enzyme and a subsequent conformational change (E1ATP(Na+)3 --> E2P(Na+)3 + ADP). The rate of the phosphorylation reaction measured by the acid quenched-flow technique was 190 s-1 at 100 microM ATP, suggesting that phosphorylation controls the kinetics of the RH421 signal and that the conformational change is very fast (>/=600 s-1). The rate of the RH421 signal was optimal at pH 7.5. The Na+ concentration dependence of 1/tau1 showed half-saturation at a Na+ concentration of 8-10 mM with positive cooperativity involved in the occupation of the Na+ binding sites. The apparent dissociation constant of the high affinity ATP binding site determined from the ATP concentration dependence of 1/tau1 was 7.0 (+/-0.6) microM, while the apparent Kd for the low affinity site and the rate constant for the E2 to E1 conformational change evaluated in the absence of Mg2+ were 143 (+/-17) microM and </= 28 s-1. At RH421 concentrations in the micromolar range, a decrease in the value of 1/tau1 is observed. On the basis of rapid quenched-flow measurements, this inhibition can be attributed to a reaction step subsequent to phosphorylation. This accounts for previously observed kinetic discrepancies between RH421 and BIPM.

Adenosine Triphosphate↗
PubMed1997

Dyggve-Melchior-Clausen syndrome without mental retardation (Smith-McCort dysplasia): morphological findings in the growth plate of the iliac crest.

Dyggve-Melchior-Clausen syndrome without mental retardation (Smith-McCort dysplasia) (SM) has clinical and radiographic findings similar to those of Dyggve-Melchior-Clausen syndrome (DMC) except for mental retardation. Iliac crest biopsies from two patients with SM were examined. The lace-like appearance of the iliac crests, which is a characteristic radiological sign of SM and DMC, was caused by bone tissue deposited in a wavy pattern at the osteochondral junction. The growth plate showed abnormal enchondral ossification with no columnarization of chondrocytes. Electron microscopy demonstrated chondrocytes with dilated cisternae of rough endoplasmic reticulum containing fine granular or amorphous material, similar to those reported in cases of DMC. Thus, SM has pathologic changes in common with DMC as a rough endoplasmic reticulum storage disorder, even though the mental condition is different.

Cartilage↗
PubMed1997

Antibody-based therapy targeting tumor vascular endothelial cells suppresses solid tumor growth in rats.

We have developed a new approach to antibody-based therapy of solid tumors by targeting tumor vascular endothelial cells (EC) which are essential for the growth of solid tumors. We investigated the effect of an antibody against tumor-derived endothelial cells (TEC) on the growth of solid tumors in rats. Intravenous administration of TES-23, a monoclonal antibody generated by TEC isolated from rat KMT-17 solid tumors, at 1 mg/rat/day for 5 days resulted in significant suppression of KMT-17 tumor growth. Histopathological analysis of tumors administered with TES-23 showed that adhesion of lymphocytes to EC followed by denudation of EC in the viable tumor area. In contrast, little obvious toxicity was observed in most of the rat organs examined. These findings suggest that the concept of an antibody-based therapy with targeting tumor vascular EC would be promising in treatment of solid tumors.

Animals↗
PubMed1997

Characterization of the cloned promoter of the human initiation factor 4AI gene.

Protein synthesis initiation factor 4AI (eIF-4AI) is ubiquitously expressed in eucaryotic cells. We characterized the eIF-4AI gene promoter cloned from human fibroblasts. The minimal promoter, localized to a region in the 5'-noncoding region adjacent to the first exon, consisted of approximately 300 base pairs (bp), 80% of which were identical with those in the corresponding mouse promoter. The minimal promoter contained TATA and CAAT motifs and consensus sequences binding to SP1 (three sites) and AP2 (one site). Deletion analyses of the promoter revealed that a 24-bp region near 5'-end of the minimal promoter was essential for the efficient transcription, although the AP2 site in the region was dispensable. A fluorescence polarization assay suggested that the plus strand of the 24-bp region, despite the lack of known consensus sequences binding to transcription factors except for AP2, bound to unknown nuclear protein(s) in a sequence specific manner.

Animals↗
PubMed1997

Prostacyclin analog-suppressed ischemia-reperfusion injury of the rat liver: evaluation by calpain mu activation.

Prostaglandin I2 has a protective effect on hepatic ischemia-reperfusion injury. However, the exact intracellular mechanisms of this effect have not been elucidated. Calpain micro, a Ca2+-dependent protease, has been found to play a role in the ischemia-reperfusion injury of various organs. The hilar area of the left lateral and median lobes of rat livers was clamped for 60 min. A prostaglandin I2 analog (OP2507, C35H41NO4) was intravenously administered at 0.1, 0.32, or 1.0 microg/kg/min from 20 min before the ischemia. In addition to biochemical and microscopic analyses, the activation of calpain mu was investigated using specific antibodies against the intermediate (activated) and preactivated forms of calpain mu. The degradation of talin was also studied by Western blotting. When OP2507 was infused at 0.32 and 1.0 microg/kg/min, bile flow significantly increased after reperfusion compared with the control group, consistent with the decrease in serum transaminase levels. Membrane bleb formation and the appearance of the intermediate form of calpain mu were observed at 60 min of ischemia in the control and OP2507 (0.1 microg/kg/min) groups and remained present until 120 min after reperfusion. OP2507 (1.0 microg/kg/min) markedly suppressed not only membrane bleb formation but also calpain mu activation and the degradation of talin. In conclusion, OP2507 suppresses ischemia-reperfusion injury of the rat liver, and its cytoprotective effect is closely associated with the inhibition of calpain mu activation.

Alanine Transaminase↗
PubMed1997

Leiomyosarcoma of the colon presenting as acute suppurative peritonitis.

A surgical case of leiomyosarcoma arising from the ascending colon, presenting as acute suppurative peritonitis, is herein described. A 70-year-old woman complaining of lower abdominal pain presented to our clinic on October 12, 1994. She was admitted with a tentative diagnosis of peritonitis. At emergency laparatomy, purulent intraabdominal fluid was present, and a fist-sized mass was seen in the ascending colon just proximal to the hepatic flexure. A right hemicolectomy was thus performed based on a diagnosis of perforating colon cancer. The histologic findings were consistent with leiomyosarcoma with abscess formation in and around the tumor. Five mitotic figures per field were observed at 10x magnification. Immunohistochemical studies revealed immunoreactivity for alpha-smooth muscle antigen (alpha-SMA), vimentin, and desmin. After reviewing the clinicopathologic characteristics of colon leiomyosarcoma as described in 78 Japanese cases and 70 cases from the foreign literature, we thus propose that colon leiomyosarcoma frequently arises from the transverse colon. In addition, our case also represents the only reported case in Japan in which an adult patient underwent a successful operation for perforated leiomyosarcoma of the colon.

Acute Disease↗