Molecular motors: thermodynamics and the random walk.

The biochemical cycle of a molecular motor provides the essential link between its thermodynamics and kinetics. The thermodynamics of the cycle determine the motor's ability to perform mechanical work, whilst the kinetics of the cycle govern its stochastic behaviour. We concentrate here on tightly coupled, processive molecular motors, such as kinesin and myosin V, which hydrolyse one molecule of ATP per forward step. Thermodynamics require that, when such a motor pulls against a constant load f, the ratio of the forward and backward products of the rate constants for its cycle is exp [-(DeltaG + u(0)f)/kT], where -DeltaG is the free energy available from ATP hydrolysis and u(0) is the motor's step size. A hypothetical one-state motor can therefore act as a chemically driven ratchet executing a biased random walk. Treating this random walk as a diffusion problem, we calculate the forward velocity v and the diffusion coefficient D and we find that its randomness parameter r is determined solely by thermodynamics. However, real molecular motors pass through several states at each attachment site. They satisfy a modified diffusion equation that follows directly from the rate equations for the biochemical cycle and their effective diffusion coefficient is reduced to D-v(2)tau, where tau is the time-constant for the motor to reach the steady state. Hence, the randomness of multistate motors is reduced compared with the one-state case and can be used for determining tau. Our analysis therefore demonstrates the intimate relationship between the biochemical cycle, the force-velocity relation and the random motion of molecular motors.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). I. Susceptibility distribution].

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the susceptibilities of them to many kinds of antimicrobial agents were investigated. The number of them were 499 strains. The breakdown of these strains was Gram-positive bacteria as 31.3% and Gram-negative bacteria as 68.7%. Susceptibilities of these bacteria to antimicrobial agents were as follows; vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) showed strong activities against Enterococcus faecalis. The increase of low-susceptible strains which was noticed in the former year showed a slight recovery in this year. VCM showed a strong activity against MRSA preventing growth of all strains with 1 microgram/ml. In addition, the activity of arbekacin (ABK) was also strong with the MIC90 of 2 micrograms/ml against MRSA. However, MSSA and MRSA showing low susceptibilities were detected in one strain each (MIC: 16 micrograms/ml and 32 micrograms/ml, respectively). Carbapenems showed high activities against Citrobacter freundii and Escherichia coli. Meropenem (MEPM) prevented growth of all strains within 0.125 microgram/ml. Quinolone resistant E. coli decreased in this year compared with those in the last year, that percentage was less than 5%. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis. MEPM and carumonam (CRMN) prevented growth of all strains within 0.125 microgram/ml. On the other hand, one strain of K. pneumoniae showing resistance to cefaclor (CCL) and one strain of P. mirabilis showing low susceptibility to most of cephems were detected. Against Pseudomonas aeruginosa, almost drugs were not so active. The MIC90s of carbapenems were 8 micrograms/ml and those of all other drugs were more than 16 micrograms/ml.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). II. Background of patients].

Five-hundred forty four bacterial strains isolated from 412 patients diagnosed as having urinary tract infections (UTIs) in 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the clinical background of patients were investigated such as sex, age and type of infections, infections and kind of bacteria, frequency of isolation of bacteria by age and infections, bacteria and infections by timing of administration of antibiotics, 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. Complicated UTIs without indwelling catheter was the most frequent among female patients aged between 40 to 59 years, in other age groups, uncomplicated UTIs was most frequent. As for type of infections and kind of bacteria, Escherichia coli decreased when the infections became complicated, and Pseudomonas aeruginosa and Enterococcus faecalis increased when the infection became complicated. Considering this result by age of patients, isolation frequency of E. coli was gradually decreased with aging in patients aged more than 20 years with uncomplicated UTIs or complicated UTIs without indwelling catheter. The isolation frequencies of E. faecalis and Staphylococcus aureus were gradually increased with aging in complicated UTIs without indwelling catheter. In patients with complicated UTIs with indwelling catheter, there was no difference between age group, and 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 patients with uncomplicated UTIs and complicated UTIs without indwelling catheter. E. coli decreased after administration of antibiotics, and P. aeruginosa and E. faecalis increased after administration in patients with all infections. As for type of causative organisms in UTIs and surgical procedures, E. coli were more frequently isolated in patients with uncomplicated UTIs when surgical procedures were experienced. Also, Klebsiella spp. and E. faecalis were more frequently isolated in patients with surgical procedures. However, in complicated UTIs, type of causative organisms had no relationship with surgical procedures.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). 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 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined and the results were compared with those obtained between 1991 and 1998. Comparison was made by classifying strains isolated from patients into those with uncomplicated UTIs and those with complicated UTIs (including with or without indwelling catheter). About E. faecalis, increase of low sensitive strains noted in the former year showed a decreasing tendency, however, one strain each with MIC of 4 micrograms/ml to vancomycin (VCM) was detected in patients with both uncomplicated and complicated UTIs. As for S. aureus, many sensitive strains to cephems, imipenem (IPM) and VCM were noted, and each MIC50 was better than that in the former years. S. aureus strains showing low susceptibility to arbekacin (ABK) were detected in patients with complicated UTIs in this year as well as in the former year, and one strain each with MIC of 16 micrograms/ml and 32 micrograms/ml was detected. Susceptibilities of E. coli were effective to all drugs except for penicillins and minocycline (MINO). Decrease of low sensitive strains was also noted in all drugs except for quinolones. Each MIC90 of ciprofloxacin (CPFX) and sparfloxacin (SPFX) in patients with complicated UTIs against E. coli was 3 degrees classes lower than that in patients with uncomplicated UTIs. As for Klebsiella pneumoniae, decrease of low sensitive strains to cephems was noted in patients with uncomplicated UTIs in 1998. In 1999, low sensitive strains decreased also in patients with complicated UTIs, and few were detected. Susceptibilities of K. pneumoniae to quinolones were effective as compared with those in the former years with the MIC80s of 0.125 microgram/ml or below without detection of low sensitive strains. One low sensitive strain of K. pneumoniae with MIC of 8 micrograms/ml was detected for gentamicin (GM). Susceptibilities of P. aeruginosa to carbapenems were notable. The MIC90 of meropenem (MEPM) and IPM was 4 micrograms/ml each which was 2 degrees better than that in 1998. Resistant P. aeruginosa strains to other drugs except for monobactams decreased in 1999.

[Rheumatoid factor].

To know the present situation of rheumatoid factor(RF) measurements, the questionnaire was sent to 82 University or College hospitals in Japan and regional 133 hospitals in Fukushima prefecture. Evaluation of qualitative RF kits commercially purchased in Japan was also performed. In RF measurement, quantitative methods have been increasingly used compared with semiquantitative or qualitative methods. Among quantitative RF measurement methods, latex immunoassay including latex-turbidimetry and latex-nephelometry is most frequently used. The reference values of RF distributed widely ranging from 5 to 40 unit. The 1997 JMA survey still showed interlaboratory differences in quantitative RF measurement. Qualitative RF kits were also shown to have variety of reactivities. To promote the improvement of current situation in RF measurement, "arbitrary" reference materials should be established urgently.

[Disorders of potassium metabolism in hemodialysis patients].

The fecal K concentration and the K-flux activity of erythrocytes were examined to investigate the role of extrarenal K excretion and K transport in peripheral tissue cells in hemodialysis patients. The fecal K concentration of hemodialysis patients was increased significantly(p < 0.01) compared to that of healthy subjects. The K-flux activity of erythrocytes and the serum K concentration correlated negatively(r = -0.482, p < 0.01) in non-diabetic hemodialysis patients, but did not correlate in diabetic hemodialysis patients. K-flux activity and Kt/V for urea correlated significantly(r = 0.412, p < 0.05). The K-flux activity of erythrocytes collected after hemodialysis therapy significantly increased (p < 0.05) compared with that of erythrocytes collected before therapy. We speculated that the K-flux activity of various cells including erythrocytes participates in the regulation of serum K in hemodialysis patients and that the inhibitory factors on K-flux activity are removed partially by hemodialysis therapy.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). III. Secular changes in susceptibility].

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Echerichia coli, Klebsiella spp. and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 9 hospitals during June 1998 to May 1999, and the results were compared with those obtained during the same period from 1990 to 1997 in uncomplicated UTIs and complicated UTIs. Among E. faecalis strains, those with low susceptibilities to almost drugs have increased in the latest period. All 5 S. aureus strains isolated from uncomplicated UTIs were the most susceptible to gentamicin (GM). Over 50% of S. aureus strains isolated from complicated UTIs were susceptible to GM, and on the contrary the resistant strains have increased with the MIC90 of 256 micrograms/ml or above. Among S. aureus strains isolated from complicated UTIs, those with low susceptibilities to arbekacin (ABK) have increased in the latest period compared to those during period of 1996-1997, and the MIC90s of them have changed into the lower state from 1 microgram/ml in 1996-1997 to 4 micrograms/ml in 1998. S. aureus strains have continued high susceptibilities to vancomycin (VCM). The susceptibilities to minocycline (MINO) of E. coli showed MIC90: 4 micrograms/ml in 1997, but those have returned in the latest period in uncomplicated UTIs. The MIC90s of ofloxacin (OFLX) to E. coli isolated from uncomplicated and complicated UTIs have been lower 2-3 classes in the latest period than those in 1997. Among Klebsiella spp. strains isolated from uncomplicated UTIs, those with low susceptibilities to almost cephems had increased in 1997, but few of them were detected in the latest study. The sensitive strains of P. aeruginosa to almost drugs have increased during the latest period. The MIC50s of cefozopran (CZOP) and OFLX against P. aeruginosa were the best in our history. The sensitive strains of P. aeruginosa to ceftazidime (CAZ) have increased and its percentage was 30%. Piperacilline (PIPC), cefoperazone (CPZ), GM and OFLX resistant P. aeruginosa strains have increased in the latest period.

[Changes in the antibacterial activity of chemotherapeutic agents (especially carbapenems) for 10 species of clinical isolates between 1994 and 1996. Surveillance group of the sensitivities of clinical isolates to antibacterial agents].

During October and December of each year of from 1994 to 1996, 3,849 strains of 10 species of bacteria were isolated from clinical materials in 21 institutions nationwide. The minimum inhibitory concentrations (MICs) for these bacteria of four carbapenems (imipenem [IPM], panipenem [PAPM], meropenem [MEPM], and biapenem [BIPM]) and other representative antibacterial agents were measured to investigate annual changes in antibacterial activity. Carbapenems showed potent activity against methicillin-sensitive S. aureus (MSSA), S. pneumoniae, E. faecalis, H. influenzae, E. coli, K. pneumoniae, E. cloacae, S. marcescens, and the B. fragilis group, with the activity being stable. However, these drugs showed weak activity against methicillin-resistant S. aureus (MRSA) and P. aeruginosa. The antibacterial activity (MIC90) against the tested organisms generally remained stable. Particularly, there was annual improvement of the MIC90 values of IPM and BIPM for S. pneumoniae, as well as the values of IPM and PAPM for H. influenzae, and those of IPM, PAPM, and BIPM for S. marcescens. On the other hand, the activity of carbapenems (including IPM) against MRSA was not necessarily strong, but there was annual improvement of MIC90 values.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). I. Susceptibility distribution].

The frequencies of bacterial isolation and susceptibilities to antimicrobial agents were investigated on 538 bacterial strains isolated from patients with urinary tract infections (UTIs) in 9 hospitals during the period of June 1998 to May 1999. Of the above bacterial isolates, Gram-positive bacteria accounted for 30.3% and Gram-negative bacteria accounted for 69.7%. Susceptibilities of several isolated bacteria to antimicrobial agents were as follows; against Enterococcus faecalis isolated from patients with UTIs, vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) had strong activities. Among E. faecalis strains, those with low susceptibilities to all drugs have increased in 1998, compared with those in 1997. VCM showed the highest activity against MRSA isolated from patients with UTIs. The MICs of VCM for all 34 strains were equal to or lower than 2 micrograms/ml. Arbekacin (ABK) was also active against MRSA with the MIC90s of 2 micrograms/ml. Against Escherichia coli and Klebsiella pneumoniae, all drugs except penicillins were active. Particularly, meropenem (MEPM) showed the highest activity with the MICs of 0.125 micrograms/ml or below. Almost all the drugs except minocycline (MINO) showed high activities against Proteus mirabilis. Against Pseudomonas aeruginosa, all drugs were not so active, with the MIC90s of 16 micrograms/ml or above. MEPM, IPM and gentamicin (GM) showed high activities against Serratia marcescens. Generally, it seemed that resistant strains of S. marcescens had decreased since 1996.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). II. Background of patients].

Clinical background was investigated on 449 patients with urinary tract infections (UTIs) from whom 591 bacterial strains were isolated in 9 hospitals during the period from June, 1998 through May, 1999. About distribution of age and sex of patients and type of infections, among males, patients less than 50 years old were few, and uncomplicated UTIs without indwelling catheters was most frequent. Among females, patients less than 20 years old were few, and uncomplicated was most frequent. Escherichia coli was the most frequently isolated in uncomplicated UTIs, and the higher the ages of patients, the higher were became the isolation frequencies of Enterococcus faecalis, Proteus spp. and Klebsiella spp. In complicated UTIs with indwelling catheters and without indwelling catheters, the types of pathogens had no relation with ages. The complication of infections had decreased E. coli but that had increased Proteus spp., Pseudomonas aeruginosa and Staphylococcus aureus. Until last year, use of antibiotics had decreased pathogens isolated from patients with uncomplicated UTIs drastically in our study. But, pathogens isolated after antibiotics had increased in 1998. As for surgical procedures and types of causative organisms in UTIs, E. faecalis were more isolated when surgical procedures were experienced, and E. coli were more isolated when they were not in uncomplicated and complicated UTIs without indwelling catheters. In complicated UTIs with indwelling catheters, types of causative organisms had no relationship with surgical procedures.

[Decision levels of sero-immunological data].

OBJECTIVES: To determine reference values in several representative serological or immunological examinations in the elderly subjects compared with young adults. MATERIALS AND METHODS: The group of elderly subjects over 70 years consisted of 630 people living at their own home and 170 people living in nursing homes. The young control group consisted of the 340 university students. ASO and RF were quantitatively measured by latex turbidimetry and FANA by immunofluorescence. Furthermore, several other autoantibodies were also examined by ELISA. The ninety-fifth percentile method was employed for the determination of reference values. RESULTS: The upper limit of reference intervals for ASO was 190 U/ml in the elderly group, while 330 U/ml in the young group. As to RF, it was 25 U/ml (70-79 years) and 37 U/ml (80-89 years), while 15 U/ml in the young. In FANA, x 160 was determined in both the elderly and the young adult subjects. Relatively higher positive frequencies were obtained in the autoantibodies to desmogrein3, dsDNA, cardiolipin and thyroglobulin in the elderly. CONCLUSION: In the elderly, ASO titers were lower, RF titers were higher, and FANA titers were generally similar to those in young adults. Higher titers were observed for some other autoantibodies.

A protein friction model of the actin sliding movement generated by myosin in mixtures of MgATP and MgGTP in vitro.

The sliding movement of an actin filament generated by myosin heads with MgGTP bound is much slower than that by those with MgATP bound. Nonetheless, there is a report that the actin sliding velocity at low (11-21 microM) MgATP concentrations is increased by the addition of MgGTP in a range of 1-3 mM, although the actin sliding velocity at these MgATP concentrations is larger than the maximum sliding velocity attained in the presence of MgGTP alone. The convex rise in the velocity was called "mutual sensitization of MgATP and MgGTP" in the report. Here we propose a theoretical model to account for the mutual sensitization of MgATP and MgGTP. The model is an extension of a protein friction model, accommodating the presence of two different substrates and assuming the presence of motile and non-motile myosins. This new model is in accord with the characteristics of the actin/myosin sliding movement experimentally observed in mixtures of MgATP and MgGTP. Comparison of the model with the experimental results implies that the non-motile and motile myosins are those with the "converse and correct" orientations of their heads with respect to the direction of the actin sliding movement in vitro.

[A case of lymphocyst infection caused by vanB type VRE].

A case of post-operative abdominal lymphocyst infection caused by vanB type vancomycin resistant enterococcus (VRE) in reported. A 27-year-old female was diagnosed as pregnancy with uterine cervical carcinoma and underwent Cesarean section and radical hysterectomy. After discharge, she developed a high fever which was diagnosed as a lymphocyst infection. Microbiological examination demonstrated the presence of vanB type VRE in the cyst fluid. Cyst cleaning and minocyclin injection were effective. This is the first case of VRE infection in Japan.

[Survey of the sensitivities of clinical isolates to antibacterial agents (annual report)].

Research groups were formed in 21 institutions nationwide to investigate carbapenem resistance. The activities of various antibacterial agents, principally carbapenems, were tested against clinical isolates collected from these institutions. The broth microdilution method was used to determine the minimum inhibitory concentrations (MIC) of 17 antibacterial agents for 1,241 strains of 11 bacterial species isolated at all institutions between October and December 1996. The results were as follows: Carbapenems exhibited strong antibacterial activities against MSSA and Streptococcus pneumoniae and showed low activities against MRSA. Their activities against Enterococcus faecalis were comparable to that of ampicillin and piperacillin. The carbapenems showed high activities against Haemophilis influenzae, Escherichia coli, Klebsiella pneumoniae. Enterobacter cloacae. Serratia marcescens and Bacteroides fragilis group. Their activities were greater than that exhibited by other beta-lactam antibacterial agents, but some resistant strains of Serratia marcescens were detected. The antibacterial activity of carbapenems against Pseudomonas aeruginosa was comparable to that of CAZ, and there were some resistant strains.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1997). III Secular changes in susceptibility].

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Echerichia coli, Klebsiella spp., and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 9 hospitals during June 1997 to May 1998, and the results were compared with those obtained during the same period in earlier years. 1. E. faecalis The MIC90s of quinolones for E. faecalis isolated from uncomplicated UTIs have changed better state during the latest period. Among E. faecalis strains, those with high susceptibilities to ampicillin (ABPC) and minocycline (MINO) appeared to had decreased during period of 1995-1997, which recovered during the latest period. 2. S. aureus The sensitive strains of S. aureus to imipenem (IPM) and clindamycin (CLDM) had increased during the period of 1996-1997, but those have decreased again during the latest period. 3. E. coli The susceptibilities of E. coli to MINO have been better in the latest period with the MIC90 was ranged from 2 to 4 micrograms/ml. The susceptibilities to quinolones of E. coli isolated from complicated UTIs had decreased during the period of 1995-1997, but those have recovered during the latest period. 4. Klebsiella spp. Among Klebsiella spp. strains isolated from uncomplicated UTIs, those with low susceptibilities to almost cephems have increased in the latest period. To other antimicrobial agents, the susceptibilities of Klebsiella spp. did not show any changes during the latest period. 5. P. aeruginosa The susceptibilities to most agents of P. aeruginosa did not show any changes, the decreased susceptibilities to cefozopran (CZOP), carbapenems and monobactams of P. aeruginosa observed in 1996 appeared to have been retrieved in 1997. These susceptibility changes should be utilized in determining clinical treatments.

Synchronous firing patterns of a set of insect neurosecretory cells.

The number of active cells in each synchronous firing event in a set of 10 neurosecretory cells in the silkmoth Bombyx mori was estimated from the amplitude and waveform of compound action potentials. One to 10 cells discharged an action potential within a period of 30 ms and one to two or nine to 10 units became active more frequently in a synchronous firing event. Numbers of active cells fluctuated like a sequence of pseudo random numbers, though the same number of cells tended to fire in two successive firing events of a short interval. These patterns suggest that electrical coupling may mediate synchronous firings in the insect neurosecretory cell system.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1997). I. Susceptibility distribution].

The frequencies of isolation and susceptibilities to antimicrobial agents were investigated on 560 bacterial strains isolated from patients with urinary tract infections (UTIs) in 9 hospitals during the period of June 1997 to May 1998. Of the above bacterial isolates, Gram-positive bacteria accounted for 29.3% and a majority of them were Enterococcus faecalis. Gram-negative bacteria accounted for 70.7% and most of them were Escherichia coli. Susceptibilities of several isolated bacteria to antimicrobial agents were as followed; 1. Enterococcus faecalis Ampicillin (ABPC) showed the highest activity against E. faecalis isolated from patients with UTIs. Its MIC90 was 1 microgram/ml. Imipenem (IPM) and vancomycin (VCM) were also active with the MIC90s of 2 micrograms/ml. The others had low activities with the MIC90s of 16 micrograms/ml or above. 2. Staphylococcus aureus including MRSA VCM and arbekacin (ABK) showed the highest activities against both S. aureus and MRSA isolated from patients with UTIs. The MIC90s of them were 1 microgram/ml. The others except minocycline (MINO) had low activities with the MIC90s of 32 micrograms/ml or above. More than a half of S. aureus strains (including MRSA) showed high susceptibilities to gentamicin (GM) and MINO, the MIC50s of 0.25 microgram/ml or 0.5 microgram/ml. 3. Enterobacter cloacae IPM showed the highest activity against E. cloacae. The MICs for all strains were equal to or lower than 1 microgram/ml. The MIC90s of ciprofloxacin (CPFX) and tosufloxacin (TFLX) were 1 microgram/ml, the MIC90s of amikacin (AMK) and ofloxacin (OFLX) were 4 micrograms/ml, the MIC90 of GM was 16 micrograms/ml. Among E. cloacae strains, those with low susceptibilities to quinolones have decreased in 1997, compared with those in 1996. But the other drugs were not so active in 1997 as 1996. 4. Escherichia coli All drugs except penicillins were active against E. coli with the MIC90s of 8 micrograms/ml or below. Particularly, flomoxef (FMOX), cefmenoxime (CMX), cefpirome (CPR), cefozopran (CZOP), IPM, CPFX and TFLX showed the highest activities against E. coli with the MIC90s of 0.125 microgram/ml or below. 5. Klebsiella pneumoniae K. pneumoniae was susceptible to almost all the drugs except penicillins. Carumonam (CRMN) had the strongest activity with the MICs for all strains equal to or lower than 0.125 microgram/ml. FMOX, CPR, CZOP, CPFX and TFLX were also active with the MIC90s of 0.125 microgram/ml or below. The MIC90s of quinolones had changed into a better state in 1997, compared with those in 1996. 6. Proteus mirabilis Almost all the drugs except ABPC and MINO showed high activities against P. mirabilis. CMX, ceftazidime (CAZ), latamoxef (LMOX), CPR, cefixime (CFIX), cefpodoxime (CPDX) and CRMN showed the highest activities against P. mirabilis. The MICs of them for all strains were equal to or lower than 0.125 microgram/ml. CPFX and TFLX were also active with the MIC90s of 0.125 microgram/ml or below. 7. Pseudomonas aeruginosa The MIC90 of GM was 8 micrograms/ml, the MIC90s of AMK, IPM and meropenem (MEPM) were 16 micrograms/ml. The others were not so active against P. aeruginosa with the MIC90s of 32 micrograms/ml or above. The MIC90s of quinolones had changed into a lower state in 1997, compared with those in 1996. 8. Serratia marcescens IPM showed the highest activity against S. marcescens. Its MIC90 was 2 micrograms/ml. GM was also active with the MIC90 of 4 micrograms/ml. The MIC90s of the others were 16 micrograms/ml or above. The MIC50s of CRMN was 0.125 microgram/ml or below, the MIC50s of CPR and CZOP were 0.25 microgram/ml.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1997). II. Background of patients].

Clinical background was investigated on patients with urinary tract infections (UTIs) from whom 603 bacterial strains were isolated in 9 hospitals during the period from June, 1997 through May, 1998. 1. Distribution of age and sex of patients and type of infections Among males, those with ages less than 50 years were only 12.5%, and those in the 70's were most frequent (33.3%). Among females, those with ages less than 20 years were only 3.4%, and those in the 60's were the most frequent (22.9%). With regard to type of infections, more than a half of infections among males with ages 50 years or older were of complicated types, but most of infections among females were of uncomplicated types, especially those of ages less than 50 years. 2. Ages of patients and types of pathogens Escherichia coli was the most frequently isolated in uncomplicated and complicated UTIs without indwelling catheters. In complicated UTIs with indwelling catheters, Pseudomonas aeruginosa and Enterococcus faecalis had mainly detected, they had no relationship with ages. 3. Effect of antibiotic use on isolation frequencies of pathogens Use of antibiotics decreased pathogens isolated from patients with uncomplicated UTIs drastically (183 isolates before antibiotics compared to 13 after). Even isolated pathogens from patients with complicated UTIs decreased drastically with the use of antibiotics when indwelling catheters were not in use (175 isolates before antibiotics compared to 53 after), but when indwelling catheters were in use, antibiotics slightly decreased (109 isolates before antibiotics compared to 70 after). 4. Surgical procedures and types of causative organisms for UTIs E. faecalis were more isolated when a surgical procedures were used, and E. coli were more isolated when, they were not used in uncomplicated and complicated UTIs without indwelling catheters. In complicated UTIs with indwelling catheters, E. coli and E. faecalis were more isolated when a surgical procedures were used, and P. aeruginosa and Staphylococcus aureus were more isolated when they were not used.

Determination of potassium flux activity of viable human erythrocytes by measuring the release-influx ratio.

A simple and convenient method to determine the K+-flux activity of viable human erythrocytes was developed. Erythrocyte suspensions were incubated at 4 degrees C for 24 h to induce K+-release (deltaKr) and then at 37 degrees C for 3 h to influx K+ into erythrocytes (deltaKi). A straight-line relationship between K+ release-influx ratio and ouabain-induced K+-efflux from erythrocytes indicated that deltaKi/deltaKr ratio or the K+-flux activity was reflected predominantly by Na+/K+-exchanging ATPase activity. Using this method, K+-flux activity of erythrocytes in the young and the aged subjects was measured. The mean deltaKi/deltaKr ratio of the aged subjects was decreased significantly. This method of measuring deltaKi/deltaKr ratio is useful for the evaluation of K+-flux activity of viable erythrocytes.

The effect of detergents on chemical occult blood test.

OBJECTIVES: Our previous investigation showed that toilet sanitizers and their main constituents, detergents, caused false negative reactions of the immunological occult blood test. Therefore, we investigated the effects of detergents on the chemical occult blood test. MATERIALS AND METHODS: Twenty-nine kinds of detergents were added to a Hb solution and measured Hb concentration by a quantitative chemical occult blood test (modified colorimetric o tolidine method) and the results were compared with those by the immunological test. The detergents' effects on Hb spectra were also analyzed. RESULTS: The chemical test was affected slightly by most of the detergents tested although the immunological test was markedly to moderately affected. The spectrum of hemoglobin was not affected by the detergents examined except for the high concentrations of SDS and DTAB. CONCLUSION: The chemical occult blood test is affected by some detergents, but less than the immunological tests.