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Yoshio Kobayashi

Publications and source records attributed to Yoshio Kobayashi.

87 records · Page 5Linked to original sources
PubMed2002

Molecular sieving and sensing with gold nanotube membranes.

We have developed a new class of synthetic membranes that consist of a porous polymeric support that contains an ensemble of gold nanotubes that span the thickness of the support membrane. The support is a commercially available microporous polycarbonate filter with cylindrical nanoscopic pores. The gold nanotubes are prepared via electroless deposition of Au onto the pore walls; i.e., the pores act as templates for the nanotubes. We have shown that by controlling the Au deposition time, Au nanotubes that have effective inside diameters of molecular dimensions (<1 nm) can be prepared. These nanotube membranes can be used to cleanly separate small molecules on the basis of molecular size. Furthermore, use of these membranes as a novel electrochemical sensor is also discussed. This new sensing scheme involves applying a constant potential across the Au nanotube membrane and measuring the drop in the transmembrane current upon the addition of the analyte. This paper reviews our recent progress on size-based transport selectivity and sensor applications in this new class of membranes.

Electrochemistry↗
PubMed2002

O2 extraction during exercise determines training effect after cardiac rehabilitation in myocardial infarction.

Correlations between baseline hemodynamic and oximetric variables during an invasive exercise test and an improvement in peak oxygen uptake (peak VO2) after exercise training (ET) were examined in 20 patients who participated in a cardiac rehabilitation program after acute myocardial infarction (AMI). Peak VO2 significantly increased by 23 +/- 21% (p < 0.01) after ET and the improvement best correlated with the change in O2 extraction fraction ([arterial O2 content-venous O2 content]/arterial O2 content) during an exercise testbefore ET (r = -0.61, p<0.01). Exercise capacity was improved to a greater extent by ET in patients with a smaller increase in O2 extraction fraction during an exercise test before ET. Thus, O2 extraction fraction during an exercise test before ET may be a useful predictor of the improvement in exercise capacity after ET in post-AMI patients.

Aged↗
PubMed2002

Acute angiographic and clinical results of the NIR w/SOX stent.

Acute angiographic and clinical results of the NIR w/SOX stent (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) were evaluated. Between March 2000 and May 2000, a total of 102 lesions in 88 patients underwent stenting with the NIR w/SOX stent. The reference vessel diameter and lesion length were 2.97 +/- 0.50 mm and 16.2 +/- 6.5 mm, respectively. The minimal lumen diameter increased from 0.68 +/- 0.45 to 3.07 +/- 0.50 mm. Stent delivery failure was observed in 4 lesions (3.9%). On the other hand, the NIR w/SOX stent was successfully delivered in 7 of 9 lesions that had unsuccessful delivery of other kinds of stents. Angiographic success was observed in all except 1 lesion where the NIR w/SOX stents could not be delivered. There were no procedural myocardial infarctions or deaths. In one case, procedural coronary bypass surgery was performed. There was no acute closure or subacute stent thrombosis. Despite unfavorable lesion characteristics, the NIR w/SOX stent achieves high procedural success and acceptable stent delivery. Furthermore, it may have a high probability to be delivered in lesions where other kinds of stent result in unsuccessful delivery.

Aged↗
PubMed2002

Percutaneous coronary intervention in a sequential radial artery graft anastomosed to the descending aorta, left circumflex artery and obtuse marginal artery.

We report percutaneous coronary intervention performed on a lesion located in a sequential radial artery graft anastomosed to the descending aorta, distal circumflex artery and obtuse marginal artery. Coronary angiography revealed an 80% stenosis in the mid-segment of the sequential radial artery graft. Conventional balloon angioplasty was performed through the proximal anastomosis at the descending aorta. The final angiogram demonstrated a good result.

Anastomosis, Surgical↗
PubMed2002

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). I. Susceptibility distribution].

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between the period of August 2000 and July 2001. Then, the susceptibilities of them to many kinds of antimicrobial agents were investigated. The number of them were 511 strains. The breakdown of these strains was Gram-positive bacteria as 29.0% and Gram-negative bacteria as 71.0%. Susceptibilities of these bacteria to antimicrobial agents were as follows; vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) showed strong activities against Enterococcus faecalis. No increase in low-susceptible strains of E. faecalis observed against these antimicrobial agents. VCM showed a strong activity against MRSA preventing growth of all strains with 1 microgram/ml. In addition, the activity of arbekacin (ABK) was strong with the MIC90 of 2 micrograms/ml against MRSA and prevented growth of all strains with 4 micrograms/ml. ABK showed a strong activity against Staphylococcus epidermidis preventing growth of all strains with 0.5 microgram/ml. ABPC, cefotiam (CTM) and cefozopran (CZOP) also showed a relatively strong activity against S. epidermidis (MIC90: 4 to 8 micrograms/ml). Against Escherichia coli, carbapenems showed high activities: meropenem (MEPM) prevented growth of all strains within 0.125 microgram/ml; IPM prevented growth of all strains with 0.25 microgram/ml. CZOP and CTM also showed strong activities against E. coli: MIC90 of CZOP was within 0.125 microgram/ml; MIC80 and MIC90 of CTM were 0.25 and 0.5 microgram/ml, respectively. Quinolone resistant E. coli was detected at frequency of 14.0%, which was significantly higher than that in the last year. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis, and MEPM prevented growth of all strains within 0.125 microgram/ml. Against Pseudomonas aeruginosa, almost drugs were not so active. The MIC90 of carbapenems and gentamicin (GM) were 16 micrograms/ml and those of all other drugs were more than 32 micrograms/ml. Against Serratia marcescens, the MIC90 of IPM and GM were the lowest value being 2 micrograms/ml, and that of MEPM was 4 micrograms/ml.

4-Quinolones↗
PubMed2002

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). II. Background of patients].

Five-hundred eighty eight bacterial strains isolated from 435 patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between August 2000 and July 2001. Then, the clinical background of patients were investigated such as sex, age, and type of infections, infections and kind of bacteria, frequency of bacteria isolation by age and infections, bacteria and infections by timing of antibiotics administration, and bacteria and infections by surgical procedures. About the relationship between age and sex of patients and type of infections, the number of male patients aged less than 50 years was few, and complicated UTIs without indwelling catheter was the most frequent. In females, the number of patients aged less than 20 years was few. The majority of female patients aged 40 years and over had complicated UTIs while uncomplicated UTIs was most frequent in the patients being twenties. As for type of infections and kind of bacteria, Escherichia coli decreased when the infections became complicated, and pseudomonas aeruginosa increased when the infection became complicated. Enterococcus faecalis was isolated more frequently in complicated UTIs than in uncomplicated UTIs. Considering this result by age of patients, isolated frequency of E. coli was gradually decreased with aging in patients aged 20 years and over with uncomplicated UTIs or complicated UTIs without indwelling catheter. The isolated frequencies of Klebsiella spp., P. aeruginosa, and E. faecalis were high in the patients with complicated UTIs without indwelling catheter. In the patients aged 70 years and over with complicated UTIs with indwelling catheter, P. aeruginosa and E. faecalis were frequently isolated. As for type of causative organisms in UTIs before and after the administration of antibiotics, the isolation of bacteria was remarkably decreased after administration in the patients with uncomplicated UTIs and complicated UTIs without indwelling catheter. E. coli decreased after administration of antibiotics, and P. aeruginosa increased after administration in the patients with all types of infections. As for type of causative organisms in UTIs and surgical procedures, E. coli was frequently isolated in the patients without surgery in all types of infections, while P. aeruginosa was frequently isolated in the patients who underwent surgery. In uncomplicated UTIs, Proteus spp. and E. faecalis were frequently isolated in the patients with surgery. In complicated UTIs without indwelling catheter, Klebsiella spp. was frequently isolated in the patients without surgery and E. faecalis was frequently isolated in the patients with surgery. In complicated UTIs with indwelling catheter, most of organisms except P. aeruginosa and S. aureus were frequently isolated in the patients without surgery.

Adolescent↗
PubMed2002

[Comparative studies on activities on antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). III. Secular changes in susceptibility].

The bacteria (Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between August 2000 and July 2001. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined, and the results were compared with those obtained between 1992 and 1999. Comparison was made by classifying strains isolated from patients into those in uncomplicated UTIs and those in complicated UTIs (including with or without indwelling catheter). E. faecalis showed good susceptibility to ampicillin (ABPC) and imipenem (IPM), and the MIC90s were 2 micrograms/ml. Also, E. faecalis showed good susceptibility to vancomycin (VCM). However, the MIC90, which was 2 micrograms/ml between 1992 and 1999, rose to 4 micrograms/ml in patients with complicated UTIs because the strains inhibited at 4 micrograms/ml increased more than before. The low susceptibility of S. aureus to arbekacin (ABK) in complicated UTIs, as shown in 1998 and 1999, recovered in 2000, and no strains inhibited at > or = 4 micrograms/ml were detected. E. coli showed good susceptibility to CTM (MIC90: 0.25-0.5 microgram/ml) and CZOP (MIC90: < or = 0.125 microgram/ml) and was not resistant to those. E. coli also showed good susceptibility to the other drugs except to penicillins. Decreases in susceptibility of E. coli to quinolones, ciprofloxacin (CPFX), and sparfloxacin (SPFX) were observed in the patients with complicated UTIs. The susceptibility of Klebsiella spp. to all drugs did not significantly change in 2000 and was generally good except to penicillins. Although the susceptibility of P. aeruginosa to carbapenems was notable, the MIC90 went up from 4 micrograms/ml to 16 micrograms/ml in complicated UTIs compared with those observed in the previous year.

Anti-Infective Agents, Urinary↗
PubMed2002

[Comparative in vitro activities of several antimicrobial agents against Helicobacter pylori].

Comparative in vitro activities of several antimicrobial agents against Helicobacter pylori were evaluated. Minimum inhibitory concentrations against 41 strains of H. pylori were determined by using E test. All 41 strains were isolated from gastric mucosa of patients suspected to have gastric ulcer. The ranges of MIC of amoxicillin was from 0.016 microgram/ml and less to 0.064 microgram/ml. The ranges of MIC of clarithromycin, erythromycin, and azithromycin were from 0.016 microgram/ml and less to 64 micrograms/ml, from 0.016 microgram/ml and less to more than 256 micrograms/ml, from 0.064 to more than 256 micrograms/ml, respectively. The ranges of MIC of ciprofloxacin, sparfloxacin, levofloxacin, norfloxacin were from 0.016 microgram/ml and less to 32 micrograms/ml, from 0.002 microgram/ml and less to more than 32 micrograms/ml, from 0.002 microgram/ml and less to more than 32 micrograms/ml, from 0.064 to more than 32 micrograms/ml, respectively.

Amoxicillin↗
PubMed1998

Coronary stent implantation throughout technical evolution: immediate and follow-up results.

Coronary stenting (stent implantation) has evolved over the last 5 years with changes in stent design, stent material and the implantation technique. The use of high-pressure balloon inflation (HP), intravascular ultrasound (IVUS) and appropriate antiplatelet therapy have contributed to the abolishment of the need for subsequent anticoagulation, allowing extended stent applications. We compared results in three groups of patients having stent implantation throughout the period of evolution: group A: no IVUS, no HP, with subsequent anticoagulation treatment (n 3 434); group B: no IVUS, yes HP, without subsequent anticoagulation treatment (n 3 192); and group C: yes IVUS, yes HP, without subsequent anticoagulation treatment (n 3 588). The primary success rates were comparable in all groups. There was a clear change in indications for stenting in groups B and C compared with group A (elective stenting: group A 3 32%; group B 3 66%; group C 3 69%; P < 0.0001), in reference vessel size (group A 3 3.22 3 0.37 mm; group B 3 2.92 3 0.56 mm; group C 3 2.98 3 0.57 mm; P < 0.0001), and for presence of type B2 and C lesions (group A 3 57%; group B 3 72%; group C 3 74%; P < 0.001). The complication rate significantly decreased in group C (group A 3 3.6%; group B 3 4.1%; group C 3 1.2%; P < 0.001) and the mean patient hospital stay decreased to 2 days in groups B and C due to the abolition of the need for anticoagulant treatment. The angiographic restenosis rate increased in groups B and C (group A 3 20%; group B 3 34%; group C 3 32%; P < 0.001). The need for a repeat procedure increased as stenting of more complex lesions and smaller vessels was attempted: target lesion revascularization (TLR) was performed in 16% of patients in group A (73/434), in 18% of group B (35/192) and in 22% of group C (129/588) (P 3 0.04 for A versus C). Major cardiac events (MACE) occurred in 142 patients in group A (33%), 60 patients in group B (31%) and in 181 patients in group C (30%). The evolving technique of coronary stenting has expanded the spectrum of indications and range of coronary vessels attempted, and decreased the complication rates and hospital stay. However, in less-favorable subsets, additional improvements are needed to affect the long-term outcome.

Journal Article↗
PubMedDate not supplied

Effects of ischemic training on leg exercise endurance.

This study tested whether ischemic exercise training (Tr(IS+EX)) would increase endurance of ischemic (Ex(IS)) and ramp exercise (Ex(RA)) knee-extension tests more than exercise training (Tr(EX)) alone. Ten healthy subjects performed pre- and posttraining tests with each leg. For Ex(RA), after subjects warmed up, a weight was added each minute until they were exhausted. Ex(IS) was similar, but after warm-up, we inflated a thigh cuff to 150 mmHg instead of adding weights. One leg was chosen for Tr(IS+EX) (cuff inflated to 150 mmHg during exercise) and the other for Tr(EX), both with a small weight on each leg, four to six times per daily session for 3 to 5 min each, 5 days per week for 6 weeks. Ex(IS) duration increased 120% more (p = 0.002) in the Tr(IS+EX) leg than in the contralateral Tr(EX) leg, whereas Ex(RA) duration increased only 16% (nonsignificant). Tr(IS+EX )and Tr(EX) significantly attenuated the ventilation increase (ergoreflex) during Ex(IS). TheO(2) debt for Ex(IS )was significantly lower and systolic blood pressure recovery was faster after Tr(IS+EX) than after Tr(EX). Heart rate recovery after Ex(RA )andEx(IS )was faster after Tr(IS+EX). Apparently, Tr(IS+EX) with low-intensity resistance increases exercise endurance and attenuates the ergoreflex and therefore may be a useful tool to increase regional muscle endurance to improve systemic exercise capacity in patients.

Adult↗