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Biomedical subjects

M Kaku

Publications and source records attributed to M Kaku.

At least 55 records · Page 3Linked to original sources
PubMed2000

Evaluation of in-vitro activity of new quinolones, macrolides, and minocycline against Mycoplasma pneumoniae.

We made a comparative study of the in-vitro activities of grepafloxacin (GPFX), ofloxacin (OFLX), erythromycin (EM), clarithromycin (CAM), roxithro-mycin (RXM), and minocycline (MINO) against 20 strains of Mycoplasma pneumoniae (17 clinical isolates and 3 standard strains). The minimum inhibitory concentration (MIC)90-to-minimum bactericidal concentration (MBC)90 ratio showed that the new quinolones have bactericidal effects on M. pneumoniae. Thus, it is expected that the new quinolones, especially grepafloxacin, will be clinically useful antimicrobial agents for the treatment of M. pneumoniae infection because of their good pharmacokinetic properties and bactericidal action.

Anti-Bacterial Agents↗
PubMed2000

Effects of insulin-like growth factor-I on nasopremaxillary growth under different masticatory loadings in growing mice.

It is well accepted that reduced masticatory function induced by a diet with soft physical consistency causes alterations in the craniofacial morphology in growing animals. It is assumed that these alterations are associated with reduced proliferative activity of osteoblasts on the bone surface, indicating a significant role for mechanical stimuli mediated by various local growth factors including insulin-like growth factor-I (IGF-I). Here, the effects of IGF-I on the linear growth of nasal and premaxillary bones subjected to different masticatory loadings were examined. The length of the nasal bone and the width of the premaxilla were measured. These dimensions were significantly greater in mice fed a solid diet than in mice fed a granulated diet. In animals treated with IGF-I, the nasal bone length and premaxillary width increased significantly in a subgroup receiving a solid diet, but these changes were not found in a similar group fed a granulated diet. No statistically significant differences in these dimensions were found between solid-diet mice injected with saline and granulated-diet group injected with IGF-I. It is concluded that IGF-I induces nasal and premaxillary growth, and that its effect is enhanced or accelerated by increased mechanical masticatory loading.

Analysis of Variance↗
PubMed2000

Detection of monoclonal proteins by capillary electrophoresis using a zwitterion in the running buffer.

Some cases have been reported in which a small monoclonal protein (M-protein) cannot be detected by conventional cellulose acetate membrane electrophoresis (CAE) or capillary zone electrophoresis (CZE) using a short fused-silica capillary. This is probably because these methods do not have the necessary sensitivity or resolution. To overcome this problem, we improved the CZE system by using a longer capillary and adding a zwitterion to the running buffer (pH 10.0). A comparison of CZE and CAE demonstrated that with the exception of alpha(1)- and alpha(2)-globulin, the correlation was satisfactory in serum samples from 34 patients with M-proteins which had been detected by immunoelectrophoresis. In addition, a comparison of CZE electropherograms with those from CAE showed that small M-proteins that went undetected by CAE could be detected by CZE in four patients whose diseases included epipharyngeal carcinoma, solitary plasmacytoma, Crow-Fukase syndrome and macroglobulinemia. The improved resolution produced by a longer capillary may be effective for the detection of small M-proteins.

Antibodies, Monoclonal↗
PubMed2000

In vitro leukemia cell models of Ara-C resistance.

Cells of the human leukemia line K562 were continuously exposed to cytosine arabinoside (Ara-C) at increasing concentrations for 3 months. The resulting cell line, termed K562/AC, showed 48-fold resistance to Ara-C, compared with the parental K562 cells. The sensitivities of K562/AC to adriamycin (ADR), vincristine (VCR) and etoposide (VP16) were similar to those of parental K562. Gene analysis revealed that this cell line lacked expression of the deoxycytidine kinase (dCK) gene, which was evident in Ara-C-sensitive cells. As in K562 cells, multidrug resistance (MDR-1) and multidrug resistance protein (MRP) genes were not expressed in K562/AC. We also established an in vitro model of Ara-C resistance using phosphorothioate antisense oligonucleotides to dCK (dCK-AS). Treatment of K562 with dCK-AS caused decreased dCK expression and 6- to 10-fold increases in resistance to Ara-C, compared with that in cells treated with sense oligonucleotides to dCK (dCK-S) or in non-transfected cells. The cells described here may contribute to the study of a novel mechanism associated with Ara-C resistance, in which reduced dCK activity may play an important role.

Antimetabolites, Antineoplastic↗
PubMed2000

Evaluation of a human monocytic cell line THP-1 model for assay of the intracellular activities of antimicrobial agents against Legionella pneumophila.

We examined the intracellular activities of 11 antimicrobial agents against Legionella pneumophila using a human monocyte-derived cell line, THP-1. Colony counting and microscopic examination of L. pneumophila co-incubated with THP-1 cells (5 x 105 cells/well) were performed. Both extra- and intra-cellular multiplication of L. pneumophila were observed and were dependent on the inoculum of L. pneumophila in the culture; L. pneumophila did not grow in the cell culture medium alone. Light microscopic examination confirmed that extracellular L. pneumophila originated from THP-1 cells disrupted by bacterial multiplication. L. pneumophila multiplied by 3-4 logs after 24 h incubation with THP-1 cells and their number remained stable at 106-107 cfu/mL until 72 h. The results of viability studies using four antimicrobial agents-ciprofloxacin, erythromycin, minocycline and rifampicin-demonstrated that our system was suitable for the intracellular activity assay. We used a concept of 'minimum extracellular concentration inhibiting intracellular multiplication' (MIEC) to evaluate the intracellular activity of antimicrobial agents. The MIECs of three beta-lactams were markedly higher than their conventional MICs while those of macrolides, quinolones, rifampicin and minocycline were similar to their MICs. Our results suggest that evaluation of the clinical efficacy of drugs against L. pneumophila should include determination of their intracellular activity against the bacteria, which could be measured using our assay system in THP-1 cells.

Anti-Bacterial Agents↗
PubMed2000

Purulent pericarditis due to group B streptococcus and mycotic aneurysm of the ascending aorta: case report.

A 61-year-old female, with a history of uterine and cervical cancer treated with radical hysterectomy and 2 years of postoperative chemotherapy, presented to the emergency department with dyspnea on exertion. Computed tomography of the chest revealed a large pericardial effusion and a sacciform aneurysm of the ascending aorta. The patient subsequently underwent emergency pericardiocentesis with drainage of approximately 330 ml of a bloody and turbid effusion. Cultures from the effusion yielded group B streptococcus. Multiple organ failure and disseminated intravascular coagulation syndrome occurred in the acute phase, but gradually improved with continuous antibiotic therapy. On the 194th hospital day, in situ reconstruction of the ascending aorta was successfully performed using a synthetic graft. Although rarely reported, both purulent bacterial pericarditis and mycotic aneurysm can be life-threatening.

Aneurysm, Infected↗
PubMed2000

[The construction of a standard RNA synthesized for quantitative RT-PCR system].

We constructed the standard RNA synthesized for the chimeric AML1-MTG8 transcripts and the house-keeping gene, glyceraldehyde-3-phosphate dehydrogenase(GAPDH) transcripts in real-time quantitative RT-PCR system. AML-MTG8 transcripts was detectable in 10 fg of synthetic RNA(3.5 x 10(3) copies). Linearity was from 3.5 x 10(3) to 3.5 x 10(9) copies. Threshold cycle(CT) is defined as the fractional cycle number at which the reporter fluorescence generated by cleavage of the probe passes a fixed threshold above baseline. The standard curve, where the known amounts of RNAs were used, showed a good correlation between the copies of AML1-MTG8 RNA and CT(r = -0.995). The within-run and day-to-day coefficients of variation(CV) in AML1-MTG8 RNA by this system were 9.5-24.7%(n = 10) and 21.7-42.2% (n = 8), respectively. GAPDH transcripts was detectable in 10 fg of synthetic RNA(6.1 x 10(4) copies). Linearity was from 6.1 x 10(4) to 6.1 x 10(8) copies. The standard curve, where the known amounts of RNAs were used, showed a good correlation between the copies of GAPDH RNA and CT(r = -0.993). The within-run and day-to-day CV in GAPDH RNA by this system were 9.3-14.6%(n = 10) and 14.7-15.8% (n = 10), respectively. Thus, we suggested that synthesized RNA as a standard RNA may be useful in quantitative RT-PCR for clinical application.

Core Binding Factor Alpha 2 Subunit↗
PubMed2000

[Genetic diagnosis for drug resistance in cancers].

The failure of chemotherapy to eradicate tumor cells is often due to the development of drug resistance. MDR(multidrug resistance) whose one form of resistance results from a decreased intracellular accumulation of the drugs, most often mediated by the overexpression of P-glycoprotein. MRP also related to pump function of cell membrane in acute leukemia. We have developed the new quantitative assay based on real-time PCR to measure expression of drug-resistance related genes such as MDR-1 and MRP in clinical samples. These results indicates that real-time PCR system is a reliable method to quantitatively determine drug resistant genes expression, it may be to predict responsiveness to chemotherapy by using this technique.

Drug Resistance, Multiple↗
PubMed2000

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group].

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

Anti-Infective Agents↗
PubMed2000

[Antibacterial activities of piperacillin in several fresh clinical isolates].

We investigated activity of piperacillin (PIPC) in comparison with 8 antibacterial reference drugs against several fresh clinical strains isolated from patients with infectious diseases in the respiratory tract and after surgical interventions in 1999. The following results were obtained: 1. PIPC had its MIC90 of 0.12-6 micrograms/ml in Gram-positive bacteria (Methicillin susceptible Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Enterococcus faecalis) and showed its MIC of 1 microgram/ml or higher in 9 possible PRSP strains out of 38 isolates of S. pneumoniae but there were no possible isolates with evident resistance in other species of bacteria. 2. PIPC showed favorable antibacterial activities as its MIC90 were 2-8 micrograms/ml in Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Citrobacter freundii, Pseudomonas aeruginosa, Moraxella (Branhamella) catarrhalis, Haemophilus influenzae), except for P. mirabilis in which its MIC90 was as high as 64 micrograms/ml. 11 out of 39 isolates of P. mirabilis were resistant to other drugs such as PIPC, ABPC, CTM and CZOP. 3. PIPC had its MIC90 of > 128 micrograms/ml in Bacteroides fragilis. From these results, PIPC was considered highly effective in several infections in view of maintaining its favorable antibacterial activities in several causative bacteria even today when 20 years had passed since its first application to clinical practice.

Bacteroides fragilis↗
PubMed2000

[Molecular diagnosis and new gene engineering in hematological malignancies].

Advancement molecular diagnostics in hematological malignancy has provided us with a broad menu of new assays and techniques. By integrating the data gleaned from these techniques we can formulate a more rational broad-based diagnosis. Hematological malignancies have traditionally been classified by morphological criteria. However, molecular advances have provided new insights in the genetic backbone of chimeric genes. These malignancies have shown chromosome abnormalities of translocation with chimeric genes, and revealed the rearrangement of chimeric genes by PCR analysis and quantitative PCR system. This review summarized the recent technology for detecting chimeric genes along with concepts of laboratory performance.

Adult↗
PubMed1999

Vascular endothelial growth factor can substitute for macrophage colony-stimulating factor in the support of osteoclastic bone resorption.

We demonstrated previously that a single injection of recombinant human macrophage colony-stimulating factor (rhM-CSF) is sufficient for osteoclast recruitment and survival in osteopetrotic (op/op) mice with a deficiency in osteoclasts resulting from a mutation in M-CSF gene. In this study, we show that a single injection of recombinant human vascular endothelial growth factor (rhVEGF) can similarly induce osteoclast recruitment in op/op mice. Osteoclasts predominantly expressed VEGF receptor 1 (VEGFR-1), and activity of recombinant human placenta growth factor 1 on osteoclast recruitment was comparable to that of rhVEGF, showing that the VEGF signal is mediated through VEGFR-1. The rhM-CSF-induced osteoclasts died after injections of VEGFR-1/Fc chimeric protein, and its effect was abrogated by concomitant injections of rhM-CSF. Osteoclasts supported by rhM-CSF or endogenous VEGF showed no significant difference in the bone-resorbing activity. op/op mice undergo an age-related resolution of osteopetrosis accompanied by an increase in osteoclast number. Most of the osteoclasts disappeared after injections of anti-VEGF antibody, demonstrating that endogenously produced VEGF is responsible for the appearance of osteoclasts in the mutant mice. In addition, rhVEGF replaced rhM-CSF in the support of in vitro osteoclast differentiation. These results demonstrate that M-CSF and VEGF have overlapping functions in the support of osteoclastic bone resorption.

Animals↗
PubMed1999

Elliptocytosis in myelodysplastic syndrome associated with translocation (1;5)(p10;q10) and deletion of 20q.

Acquired elliptocytosis is a red blood cell abnormality occasionally associated with myelodysplastic syndrome (MDS). A Japanese male with MDS who presented with elliptocytosis had mild anemia and hypercellular bone marrow with three lineage-dysplasia. He was diagnosed with refractory anemia of MDS. Cytogenetic analysis of bone marrow cells showed 47,XY,+1,der(1;5)(q10;p10),t(1;5) (p10;q10),del(20)(q11) in 70% of the analyzed cells. Analysis of red blood cell membrane proteins by sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed normal electrophoretic patterns with no quantitative abnormalities of each protein. Del(20q) and/or t(1;5)(p10;q10) might be associated with elliptocytosis in this patient.

Aged↗
PubMed1999

Recruitment of osteoclasts in the mandibular condyle of growing osteopetrotic (op/op) mice after a single injection of macrophage colony-stimulating factor.

The purpose was to elucidate histological changes in the mandibular condyle and ramus in growing osteopetrotic (op/op) mice after a single injection of macrophage colony-stimulating factor (M-CSF). M-CSF (5 microg) was injected into 6-, 11-, 26-, 56- and 86-day-old op/op mice, and the mice were killed 4 days after the injection. In normal mice, the condyle was substantially wider than the ramus beneath it, and enlargement and ossification of the condyle occurred after weaning. These changes were not found in the uninjected and injected op/op mice, the condyles of which were occupied by hypertrophic cartilage cells, and the hypertrophic cell layer was thicker and more irregular in the arrangement of epiphyseal cell columns. In spite of the lack of bone resorption in uninjected and injected op/ op mice, ossification of the mandibular ramus occurred, but later than that of normal mouse. The number of tartrate-resistant acid phosphatase-positive cells in the injected op/op and normal mice approached a maximum at 30 days and then gradually decreased up to 90 days of age, although the numbers were substantially different for all ages. The uninjected op/op mice had no visible osteoclasts until 15 days and their number then increased significantly from 60 to 90 days of age. These results were considered due to the difference in biological responses of bony structures to M-CSF injection in the op/op mice. The influences of mechanical stimuli from masticatory functions, which are deficient in op/op mice, might also be responsible for the differences in bony architecture between the op/op and normal mice.

Animals↗
PubMed1999

Late expression of red cell membrane protein 4.2 in normal human erythroid maturation with seven isoforms of the protein 4.2 gene.

The expression of protein 4.2 in normal human erythroid cells was studied utilizing erythroblasts from bone marrow and erythroid cells cultured by the two-phase liquid culture method from burst-forming unit erythroid (BFU-E) in peripheral blood. As opposed to spectrin, which was expressed in erythroid progenitors or very early erythroblasts, protein 4.2 was first detected in late erythroblasts with a morphology nearly identical to orthochromatic erythroblasts. Among the various major membrane proteins, the expression of protein 4.2 was the latest. At the gene level, protein 4.2 gene mRNA was expressed in early erythroblasts. During normal erythroid maturation, the expression of seven different protein 4.2 gene products was observed by Southern blot analysis. These seven gene products appeared to be derived from protein 4.2 gene in the presence or absence of skipping of the 90 bp in exon 1, exon 3, and/or exon 5, as judged by deduction from the protein 4.2 sequence. Therefore, it can be speculated that protein 4.2 is expressed after the cytoskeletal network has been constructed and assembled with integral proteins in the membrane lipid bilayer.

Blood Proteins↗
PubMed1999

Serotypes VI and VIII predominate among group B streptococci isolated from pregnant Japanese women.

Infection by group B streptococcus (GBS) is an important cause of bacterial disease in neonates, pregnant women, and nonpregnant adults. Whereas serotypes Ia, Ib, II, III, and V are most commonly associated with colonization and disease in the United States, strains of other serotypes have been isolated from patients in Japan. By use of an inhibition ELISA, the serotypes of 73 vaginal colonizing GBS strains isolated from healthy pregnant Japanese women were investigated. Twenty-six (35.6%) were type VIII, 18 (24.7%) were type VI, and the remaining 29 were distributed among more traditional serotypes. Strains were also tested by immunoblot for the presence of GBS surface proteins. Fifty-three (72.6%) of the 73 strains expressed one or more laddering GBS proteins. These data show that type VI and VIII GBS strains are common vaginal isolates in pregnant Japanese women and that one or more laddering proteins are present in most GBS strains.

Bacterial Proteins↗
PubMed1999

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

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

Anti-Bacterial Agents↗