Biomedical subjects

K Shimokata

Publications and source records attributed to K Shimokata.

At least 73 records · Page 4Linked to original sources

PubMed1997

Combination effects of cisplatin, vinorelbine and irinotecan in non-small-cell lung cancer cell lines in vitro.

PURPOSE: Isobologram analysis has been widely used for evaluating the combined effect of two antitumor drugs in vitro as a pre-clinical screening test. In this study, we tried to extend two-dimensional isobologram analysis to three dimensions for evaluating the effects of a three-drug combination. METHODS: We selected three anticancer agents, cisplatin, vinorelbine and irinotecan. Each of them has been classified as having good single-agent activity against non-small-cell lung cancer (NSCLC). Human NSCLC cell lines (EBC-1, PC-3, RERF-LC-MS) were incubated for 4 days in the presence of the three drugs and cytotoxic activities were determined by a tetrazolium-based colorimetric assay (MTT assay). The data were analyzed by three dimensional isobologram analysis. RESULTS: The effects of the three drugs were additive against EBC-1 (a squamous cell carcinoma cell line), subadditive against PC-3 (an adenocarcinoma cell line) and from subadditive to supraadditive against RERF-LC-MS (an adenocarcinoma cell line). CONCLUSIONS: Our findings suggest that the effects of cisplatin, vinorelbine and irinotecan in combination are additive against NSCLC in vitro. These results encourage clinical trials of the three agents in combination chemotherapy for the treatment of NSCLC.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Chemotherapy for small-cell lung cancer: more is not better.

As have many other chemosensitive tumors, small-cell lung cancer (SCLC) has a well-documented chemotherapy dose-response relationship. However, a relationship between dose and survival has not yet been established. The effect of dose on survival should be examined in terms of both the dose used over a certain period (dose intensity) and the total dose of drugs employed, and neither the total dose of drugs used nor the duration of maintenance chemotherapy has been proven to provide an overall survival benefit. In the case of the dose-intensive approach there is no evidence for a significant survival benefit of either high-dose or dose-intensive weekly chemotherapy. Stem-cell support may be a promising means of increasing dose intensity, but the indications are limited and it should be considered highly experimental. Given the relatively good condition of patients in most comparative clinical trials, more is not better in chemotherapy for SCLC, at least in clinical practice.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Adjustment of creatinine clearance improves accuracy of Calvert's formula for carboplatin dosing.

Carboplatin clearance depends on the glomerular filtration rate (GFR), and Calvert's formula is frequently used to achieve a target area under the time vs concentration curve (mg ml(-1) min). Creatinine clearance is a substitute for GFR when creatinine values are determined by the Jaffé method, which is being replaced by the enzymatic method. When the enzymatic method is used, the corresponding creatinine clearance theoretically exceeds GFR, and the use of creatinine clearance as GFR in Calvert's formula results, accordingly, in overdosing of carboplatin. In this study, we have established a model for adjusting the creatinine clearance to offset this bias based on a relationship between creatinine values measured by the Jaffé method and by the enzymatic method: adjusted creatinine clearance (ml min(-1)) = creatinine clearance (ml min(-1)) x [serum creatinine (mg dl(-1))]/[serum creatinine (mg dl(-1)) + 0.2]. Subsequently, we validated this model using the data from 35 lung cancer patients. Estimated clearances of carboplatin with the original equation [creatinine clearance + 25] were systematically higher than observed clearances [mean prediction error (MPE) +/- standard error (s.e.) = 26 +/- 5%]. This positive bias was corrected by the adjustment (MPE +/- s.e. = 5 +/- 4%). When the enzymatic method is used, the adjusted creatinine clearance should be used in Calvert's formula.

Adult↗

PubMed1997

Nodular granulomatous phlebitis of the skin: a fourth type of tuberculid.

We present five cases of granulomatous phlebitis of the skin and compare them with a case of miliary tuberculosis with granulomatous phlebitis. All five patients were hypersensitive to purified protein derivative, but without active tuberculosis. Although anti-tuberculous drugs were effective, no tubercle bacilli were isolated from the skin. Clinically, subcutaneous nodules were felt along the course of the leg vein. Histologically, epithelioid cell granulomas with Langhans' giant cells were observed within the walls of the cutaneous veins. In a later stage, granulomatous panniculitis was often associated. Using the polymerase chain reaction method. Mycobacterium tuberculosis DNA was detected in four of the five cases of granulomatous phlebitis of the skin. Granulomatous phlebitis of the skin seems to represent a relatively early phase of delayed-type hypersensitivity reactions to Mycobacterium tuberculosis and may represent a distinct entity different from other types of tuberculid-a new tuberculid. Nevertheless, before making the diagnosis, the possibility of true tuberculosis must always be excluded. Nodular granulomatous phlebitis of the skin would be an appropriate name for the newly described condition.

Aged↗

PubMed1997

A clinical and bacteriologic investigation of invasive streptococcal infections in Japan on the basis of serotypes, toxin production, and genomic DNA fingerprints.

In a survey of invasive streptococcal infections in Japan, we analyzed isolates of Streptococcus pyogenes collected between 1992 and 1994. Genomic DNA fingerprints produced by pulsed-field gel electrophoresis (PFGE) were compared by computer-assisted analysis. Conventional serologic M types were subdivided into PFGE types showing close genetic similarity. Among the 42 isolates from patients with invasive diseases, 16 PFGE types were identified and genetic diversity was clearly demonstrated. Identical fingerprints were observed in both invasive and noninvasive isolates. Only 43% of invasive isolates produced streptococcal pyrogenic exotoxin A (SPE A), and 31% did not contain the speA gene. These findings suggest that the dissemination of a specific clone is not sufficient to explain all cases of these diseases in Japan and pose a question as to the role of SPE A as a major virulent factor. Bacterial factors other than SPE A and host factors should be considered in evaluation of the pathogenesis of the diseases.

Antibodies, Bacterial↗

PubMed1997

Transmission of Streptococcus pyogenes causing toxic shock-like syndrome among family members and confirmation by DNA macrorestriction analysis.

Streptococcus pyogenes can cause severe infections, such as toxic shock-like syndrome (TSLS). The transmission and pathogenesis of TSLS are poorly understood, and information is needed to develop prevention strategies. Four cases were identified in which the organism was transmitted among patients with TSLS and their family members. DNA macrorestriction endonuclease analysis using pulsed-field gel electrophoresis demonstrated the spread of S. pyogenes clones that caused TSLS among the family members. Although 14 persons related to the case-patients experienced only colonization or self-limited disease, 3 developed invasive infections (pneumonia, severe pharyngitis requiring hospitalization, and puerperal sepsis). These findings indicate that antimicrobial prophylaxis for close contacts of patients with TSLS should be considered and reinforce the need for further studies on epidemic control of TSLS.

Adult↗

PubMed1997

Substrate recognition by mitochondrial processing peptidase toward the malate dehydrogenase precursor.

Mitochondrial processing peptidase (MPP) cleaves the extension peptides of precursor proteins newly imported into the mitochondria. Using synthetic oligopeptides modeled on the extension peptide of malate dehydrogenase, the critical elements of the substrate for the processing of MPP were determined [Niidome, T., Kitada, S., Shimokata, K., Ogishima, T., and Ito, A. (1994) J. Biol. Chem. 269, 24719-24722; Ogishima, T., Niidome, T., Shimokata, K., Kitada, S., and Ito, A. (1995) ibid. 270, 30322-30326]. In the present study, we constructed mutant precursors and compared the processing reaction with that of the peptide substrates to confirm the validity of use of peptide substrates. In both cases, the arginine residue presents at a proximal (-2) position relative to the processing site proved to be important for the processing. The distal arginine residue at position 7 was replaceable with alanine with no significant loss in cleavage efficiency if the precursor protein contained two consecutive arginine residues at a proximal position, although the arginine residue at a position 7 was indispensable in the model peptide. The proline residue, lying between the distal and proximal arginine residues, which is assumed to break a continuous alpha-helix region in the extension peptide, was needed for the processing. This peptidase has a preference for aromatic amino acids at the P1' site. These results were essentially the same as those obtained with model peptides except for the role of the distal arginine. We also found that amino acids at P2' and P3' sites had some effects on the processing. Thus we concluded that an effective combination of model peptides with precursor proteins is needed for the studies on MPP responsible substrate-recognition mechanisms.

Amino Acid Sequence↗

PubMed1997

Pharmacokinetic study of carboplatin given on a 5-day intravenous schedule.

We investigated whether carboplatin pharmacokinetics is altered when the drug is delivered daily over 5 days, compared to a single-day infusion. Carboplatin was infused in 11 patients with lung cancer, who were randomly assigned to 2 groups. In the first group, the agent was administered on a conventional single-day schedule in the first course and then on a 5-day schedule in the second course. In the second group, the order was reversed (crossover design). The dose was calculated using Calvert's formula with 24 h creatinine clearance (Ccr, ml/min) as a substitute for glomerular filtration rate (GFR): carboplatin (mg) = AUCx(Ccr+25), where AUC denotes the area under the concentration versus time curve (mg ml-1 min). No difference of carboplatin clearance between the single-day and 5-day schedule was observed (94.8 +/- 19.9 versus 96.1 +/- 29.9 ml/min, P = 0.818, paired t test). The formula systematically overestimated the carboplatin clearance: the ratio of estimated clearance/ observed clearance ranged from 1.01 to 1.58 (median 1.28; 95% confidence interval, 1.18 to 1.39). We concluded that the individual dosing strategy based on renal function can be applied with a 5-day schedule as well as a single-day schedule. Carboplatin is overdosed when Ccr is substituted for GFR in Calvert's formula.

Aged↗

PubMed1997

Recording of electroencephalograms and electrocardiograms during daytime sleep in trained canines: preparation of the sleeping dogs.

Although respiration in trained canines is well investigated, the process of preparing dogs has not been described in any great detail. Moreover, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (ECG) recordings are not clear. Therefore, we describe the process of selecting and training dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this training procedure was repeated 152 times. Three dogs were then selected and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with the bipolar fine needle electrodes; respiration was recorded simultaneously through a tube inserted to a tracheostomy in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movement (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9-4.1 times. The mean duration of SWS was 2.2-4.4 min and that of REMS was 3.5-4.6 min. The REMS latency was 33.9-41.8 min. Fluctuation of heart rate with respiration, termed respiratory sinus arrhythmia, was noted in the ECG. Heart beat increased with inspiration and decreased with expiration. The present study demonstrates how to select and train sleeping dogs and shows their undisturbed daytime sleep and wakefulness patterns.

Animals↗

PubMed1997

Nosocomial spread of cephem-resistant Escherichia coli strains carrying multiple Toho-1-like beta-lactamase genes.

Escherichia coli HKY56, which demonstrated resistance to various beta-lactams except carbapenems, was isolated from the throat swab of an inpatient in 1994. Conjugal transfer of cephem resistance from HKY56 to E. coli CSH2 was not successful. Three cefotaxime-resistant E. coli clones harboring plasmid pMRE001, pMRE002, or pMRE003, each of which carried a 3.4-, 5.8-, or 6.2-kb EcoRI fragment insert, respectively, were obtained from HKY56. Although restriction analysis suggested their different origins, these clones showed similar profiles of resistance to various beta-lactams. The sequence of 10 amino acid residues at the N terminus of beta-lactamase purified from E. coli HB101(pMRE001) was identical to that of Toho-1. This Toho-1-like beta-lactamase-1 (TLB-1) was able to hydrolyze cefoperazone and cefotaxime efficiently, but it failed to hydrolyze cephamycins. A Toho-1-specific DNA probe was hybridized with three distinct EcoRI fragments derived from the chromosomal DNA of strain HKY56, and these fragments corresponded to DNA inserts carried by pMRE001, pMRE002, and pMRE003, respectively. PCR and Southern hybridization analysis suggested that all six cephem-resistant E. coli strains, strains HKY273, HKY285, HKY288, HKY305, HKY316, and HKY335, which were isolated in 1996 at the same hospital where strain HKY56 had been isolated, also possessed multiple Toho-1-like beta-lactamase (TLB) genes, and the hybridization patterns obtained with the Toho-1-specific probe were quite similar among these six isolates. The DNA fingerprinting patterns observed by pulsed-field gel electrophoresis revealed that among the E. coli isolates tested, all isolates except HKY56 possessed a similar genetic background. These findings suggested that E. coli strains that carry chromosomally multiplied TLB genes may have been proliferating and transmitted among patients in the same hospital.

Carbapenems↗

PubMed1997

Mechanism of nitric oxide-dependent killing of Mycobacterium bovis BCG in human alveolar macrophages.

We demonstrated that products of the L-arginine-dependent pathway of human alveolar macrophages (AM) effectively kill the Mycobacterium bovis bacillus Calmette-Guérin (BCG) in vitro. The formation of products was triggered by inoculation with BCG itself. Many reports have shown that activated rodent AM could produce an amount of nitric oxide (NO) sufficient to suppress the growth of mycobacteria. However, there have been no definitive results as to whether human AM might have the NO-dependent mechanism for the killing of mycobacteria. Therefore, we have undertaken some experiments to answer this question. Immunofluorescence assays showed an increased production of inducible nitric oxide synthase (iNOS) and peroxynitrite in BCG-inoculated AM from patients with pulmonary fibrosis. Reverse transcriptase-PCR also revealed the higher expression of iNOS-coding mRNA. Colony assays demonstrated that these human AM effectively killed BCG in their cytoplasm. However, treatment of AM with N(G)-monomethyl-L-arginine monoacetate resulted in markedly reduced killing activity. These results clearly show that BCG-induced NO and its reactive product with the oxygen radical peroxynitrite could play an important role in the killing of BCG in human AM.

Bronchoalveolar Lavage↗

PubMed1997

Diagnostic value of the strand displacement amplification method compared to those of Roche Amplicor PCR and culture for detecting mycobacteria in sputum samples.

We compared the ability of the semiautomated BDProbeTec-SDA system, which uses the strand displacement amplification (SDA) method, with that of the Roche Amplicor-PCR system and the Septi-Chek AFB culture system to directly detect Mycobacterium tuberculosis complex (MTB) and other mycobacteria in sputum samples. A total of 530 sputum samples from 299 patients were examined in this study. Of the 530 samples, 129 were culture positive for acid-fast bacilli with the Septi-Chek AFB system; 95 for MTB, 29 for M. avium-M. intracellulare complex (MAC), and 5 for other mycobacteria. The BDProbeTec-SDA system detected 90 of the 95 samples culture positive for MTB (sensitivity, 94.7%), and the Amplicor-PCR system detected 85 of the 95 samples culture positive for MTB (sensitivity, 89.5%). The specificity of each system, based on the clinical diagnosis, was 99.8% for SDA and 100% for PCR, respectively. Among the 29 samples culture positive for MAC, the BDProbeTec-SDA system detected MAC in 24 samples (sensitivity, 82.8%), whereas the Amplicor-PCR system detected MAC in 23 samples (sensitivity, 79.3%). The specificities of the systems were 98.3 and 100%, respectively. The high degrees of sensitivity and specificity of the BDProbeTec-SDA system suggest that it should be very useful in clinical laboratories for the rapid detection of mycobacteria in sputum samples.

Bacteriological Techniques↗

PubMed1997

Large-restriction-fragment analysis of Mycobacterium kansasii genomic DNA and its application in molecular typing.

Large-restriction-fragment (LRF) polymorphisms in Mycobacterium kansasii isolates from 84 patients with bronchopulmonary infections in Japan between the 1960s and 1995 were studied by pulsed-field gel electrophoresis (PFGE). Chromosomal fragments digested with VspI were most suitable for PFGE separation of 16 to 21 fragments of between 40 and 550 kbp. All 84 isolates and the type strain M. kansasii ATCC 12478 were successfully typed by LRF analysis with VspI digestion. Twenty-one distinctive LRF types were identified, and the LRF patterns tested over time were reproducible and stable. A computer-assisted dendrogram of the percent similarity demonstrated that isolates of 18 LRF types had relatively close genetic relatedness, while isolates of the remaining 3 types showed divergence. Sequence analysis of the 16S rRNA gene in the isolates showing divergent genetic relatedness revealed a sequence identical to that of a previously reported subspecies of M. kansasii. In the Chugoku district of Japan, 11 cases of M. kansasii infection which occurred in workers in a coastal industrial zone between 1982 and 1993 were caused by one particular strain tentatively named LRF type M. When both detailed demographic data for the patients and ecologic data for the M. kansasii isolates are obtained, LRF typing may be of potential use for investigating the source and transmission of M. kansasii infection.

Bacterial Typing Techniques↗

PubMed1997

Determination of anti-streptolysin O antibody titer by a new passive agglutination method using sensitized toraysphere particles.

We developed a new method for determining the anti-streptolysin O (ASO) titer on the basis of a passive agglutination reaction. This new method uses Toraysphere particles sensitized with streptolysin O. This method was used to measure the ASO titer in 130 serum samples (from 31 patients with post-streptococcal glomerulonephritis, 26 patients with group A streptococcal pharyngitis, 5 patients with scarlet fever, 29 patients with non-group A streptococcal pharyngitis, 20 healthy children, and 19 healthy adults). The results were compared with those obtained simultaneously by two conventional methods, the Rantz-Randall and the NA-Latex-ASL methods. The results obtained by the Toraysphere method showed an excellent correlation with those obtained by each conventional method (correlation coefficients, 0.932 for the Rantz-Randall method and 0.913 for the NA-Latex-ASL method). The performance of each method was evaluated with respect to the clinical and microbiological diagnoses for each patient. The sensitivity, specificity, positive predictive value, and negative predictive value for the Toraysphere method were 76, 84, 81, and 79%, respectively. The corresponding values for the Rantz-Randall method were 48, 78, 67, and 62%, respectively, while those for the NA-Latex-ASL method were 60, 82, 76, and 69%, respectively. Because the Toraysphere method is simple and reproducible, has a short reaction time, and has a clear-cut endpoint for the analysis, we recommend it for routine use in determining the ASO titer in the clinical microbiology laboratory.

Adolescent↗

PubMed1997

Exfoliative toxin detection using reversed passive latex agglutination: clinical and epidemiologic applications.

A rapid and simple method for detecting exfoliative toxin serotypes A and B from clinical isolates has been developed as a test kit (EXT-RPLA; Denka Seiken Co. Ltd., Niigata, Japan). This method is based on reversed passive latex agglutination. The detection limit of the EXT-RPLA observed for purified exfoliative toxin serotypes A and B was 1 ng/ml. We evaluated the clinical and epidemiologic uses of the EXT-RPLA. A total of 381 isolates of Staphylococcus aureus, 292 from various clinical specimens and 89 from the skin of dermatologic patients, were studied. The EXT-RPLA detected 19 exfoliative toxin producers, including 16 serotype A producers and 3 serotype B producers, but no double producers. The sensitivity and specificity of the EXT-RPLA were confirmed by the newborn mouse bioassay and a PCR assay for the structural genes for exfoliative toxin serotypes A and B (eta and etb, respectively). The overall positivity rate of exfoliative toxin producers was 5.0% (19 of 381), including 16 serotype A isolates and 3 serotype B isolates. Of the 89 isolates from the skin of dermatologic patients, 12 (13.5%) were positive for exfoliative toxin production. Only 2 (1.3%) of the 153 methicillin-resistant S. aureus isolates produced exfoliative toxin, while 17 (7.5%) of the 228 methicillin-sensitive isolates produced exfoliative toxin. The EXT-RPLA assay is a simple and reliable method for detecting exfoliative toxin, and we recommend its use for the rapid diagnosis of staphylococcal scalded skin syndrome. We also recommend its use for detection of this syndrome so that effective control measures can be taken against the spread of this syndrome.

Agglutination Tests↗

PubMed1997

Mycobacterium growth indicator tube testing in conjunction with the AccuProbe or the AMPLICOR-PCR assay for detecting and identifying mycobacteria from sputum samples.

We have compared the ability of the Mycobacterium Growth Indicator Tube (MGIT) system, a new culture method with an oxygen-sensitive fluorescent sensor, to recover mycobacteria from sputum samples with the abilities of egg-based medium and the Septi-Chek AFB system. We have also assessed the clinical utility of the AccuProbe or the AMPLICOR-PCR assay to directly identify Mycobacterium tuberculosis complex and M. avium-M. intracellulare complex (MAC) from positive MGITs. From 382 sputum samples, 99 isolates of M. tuberculosis complex and 20 isolates of MAC were recovered. The MGIT system had the highest recovery rates for M. tuberculosis complex (97.0%) and MAC (100%), compared to recovery rates of 51.5 and 65.0%, respectively, with the egg-based medium and 81.8 and 85.0%, respectively, with the Septi-Chek AFB system. The shortest recovery times were also achieved with the MGIT system: 16.6 days for M. tuberculosis complex and 12.0 days for MAC, compared to 27.1 and 20.1 days, respectively, with the egg-based medium and 21.4 and 13.2 days, respectively, with the Septi-Chek AFB system. The AccuProbe identified 74 (77.1%) of the 96 M. tuberculosis complex-positive MGITs and 17 (85.0%) of the 20 MAC-positive vials. The AMPLICOR system correctly identified 94 (97.9%) of the 96 M. tuberculosis complex-positive MGITs and all 20 MAC-positive vials. Therefore, the MGIT system used in conjunction with the AMPLICOR system is a rapid and sensitive method for detecting and identifying M. tuberculosis complex and MAC isolates from sputum samples.

DNA, Bacterial↗

PubMed1997

Nitric oxide as an inflammatory mediator of radiation pneumonitis in rats.

Radiation pneumonitis is a major complication of radiation therapy. To elucidate the mechanisms of radiation-induced pneumonitis, we studied nitric oxide (NO) produced from lung tissues using a model of unilaterally irradiated rats. Our results demonstrated that alveolar macrophages (AM) produced NO after irradiation, and the expression of inducible NO synthase (NOS) in both AM and alveolar epithelial cells was increased. Furthermore, the progression of radiation pneumonitis was reduced with the in vivo treatment of the NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). The effect of L-NAME was further confirmed by the inhibition of mRNA expression for procollagen-alpha1 type III of the lung. With these results, NO produced from AM and alveolar epithelial cells after irradiation may be an important mediator in the progression of radiation pneumonitis.

Animals↗

PubMed1997

Comparison of resting beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and thallium-201 tomography using quantitative polar maps in patients with unstable angina.

We compared resting beta-methyl-iodophenyl pentadecanoic acid (BMIPP) tomography with resting thallium-201 tomography in 28 patients with unstable angina. Tracer distribution was displayed on a polar map and compared with a normal standard deviation map obtained from a group of 12 normal subjects. The extent scores and severity scores obtained by BMIPP were significantly greater than those obtained by thallium-201. Confirmation by coronary angiography revealed the sensitivity of the methods in identifying patients to be 89% for BMIPP and 54% for thallium-201. There were significant differences between BMIPP and thallium-201 in the sensitivities of detecting postischemic jeopardized myocardium in the area supplied by the right coronary artery (RCA; 53% vs 18%, p < 0.05), left circumflex artery (LCX; 78% vs 39%, p < 0.025) and all 3 vessels combined (71% vs 35%, p < 0.001) but no significant differences in specificity (RCA: 82% vs 64%; LCX: 70% vs 90%; and total 3 vessels combined: 75% vs 79%). In conclusion, resting BMIPP tomography is more sensitive than resting thallium-201 tomography in detecting postischemic myocardial damage in patients with unstable angina.

Angina, Unstable↗