Search PubMed⌕ Search

Biomedical subjects

N Masuda

Publications and source records attributed to N Masuda.

At least 109 records · Page 6Linked to original sources
PubMed1996

Determinants of myelosuppression in the treatment of non-small cell lung cancer with cisplatin-containing chemotherapy.

Data on 16 potential risk factors for myelosuppression were assessed in 134 patients who received either vindesine and cisplatin (VP) or mitomycin C, vindesine and cisplatin (MVP) for inoperable stage III or IV non-small cell lung cancer in a randomized trial. Determinant factors for myelosuppression were evaluated by using univariate analysis and the logistic regression model. Recursive partitioning and amalgamation (RPA) was also used to define patient subgroups frequently suffering from severe bone marrow toxicity. Overall, 33 (25%) of 134 patients experienced at least one episode of grade 4 leukopenia. In univariate analysis, age, body surface area, serum creatinine, and pretreatment hemoglobin concentration were associated with severe leukopenia. A multivariate analysis using the logistic regression method showed that only raised creatinine level was an independent predictor for grade 4 leukopenia (P = 0.049). The RPA model generated three distinct subgroups based on age, body surface area and regimen. The three subgroups were distinguished by the frequency of severe (grade 4) leukopenia (50%, 25%, and 2.4%, respectively) (P < 0.001). Grade 4 leukopenia occurred more frequently in patients in class 3 (age > or = 65 years and treatment with MVP). The RPA model was useful in identifying the risk factors for myelosuppression induced by cisplatin-based chemotherapy, and in defining patient subgroups with elevated risk of toxicity.

Adult↗
PubMed1996

Quantitative correlation between susceptibility and OprJ production in NfxB mutants of Pseudomonas aeruginosa.

Various Pseudomonas aeruginosa PAO1 NfxB mutants were isolated on agar plates containing cefpirome and ofloxacin. They were classified into type A and type B, based on the degrees of changes in their susceptibilities. Type A mutants were four to eight times more resistant to ofloxacin, erythromycin, and new zwitterionic cephems, i.e., cefpirome, cefclidin, cefozopran, and cefoselis, than was the parent strain, PAO1. In contrast, type B mutants were more resistant to tetracycline and chloramphenicol, as well as ofloxacin, erythromycin, and the new zwitterionic cephems, than was PAO1, and they were four to eight times more susceptible to carbenicillin, sulbenicillin, imipenem, panipenem, biapenem, moxalactam, aztreonam, gentamicin, and kanamycin that was PAO1. The changes in susceptibilities of type B mutants were greater than those of type A mutants. The susceptibilities of both type A and type B mutants were restored to the level of PAO1 by transformation with plasmid pNF111, which contained the wild-type nfxB gene, demonstrating that they are NfxB mutants. Immunoblot analysis with a monoclonal antibody to OprJ revealed that type B mutants produced larger amounts of outer membrane protein OprJ than did type A mutants and that PAO1 produced an undetectable amount of it. Moreover, transconjugants obtained with the different types of NfxB mutants as the donor strains showed almost the same phenotypes as the corresponding donor strains. These results suggest that there are at least two nfxB mutations that show different phenotypes and that production of OprJ is associated with changes in susceptibilities of NfxB mutants.

Anti-Bacterial Agents↗
PubMed1996

In vitro and in vivo antibacterial activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone.

The in vitro and in vivo activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone, were compared with those of ciprofloxacin, tosufloxacin, sparfloxacin, and levofloxacin. The in vitro activity of CS-940 against gram-positive bacteria was nearly equal to or greater than those of the other quinolones tested. In particular, CS-940 was two to eight times more active against methicillin-resistant Staphylococcus aureus than the other quinolones, at the MIC at which 90% of the clinical isolates are inhibited. Against gram-negative bacteria, the activity of CS-940 was comparable to or greater than those of tosufloxacin, sparfloxacin, and levofloxacin, while it was lower than that of ciprofloxacin. The activity of CS-940 was largely unaffected by medium, inoculum size, or the addition of horse serum, but it was decreased under acidic conditions, as was also seen with the other quinolones tested. CS-940 showed potent bactericidal activity against S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In oral treatment of mouse systemic infections caused by S. aureus, Streptococcus pneumoniae, Streptococcus pyogenes, E. coli, K. pneumoniae, Serratia marcescens, and P. aeruginosa, CS-940 was more effective than ciprofloxacin, sparfloxacin, and levofloxacin against all strains tested. Against experimental pneumonia with K. pneumoniae in mice, CS-940 was the most effective of all the quinolones tested. These results suggest that CS-940 may be effective in the therapy of various bacterial infections.

Animals↗
PubMed1996

Lead inhibits nitric oxide production transiently by mRNA level in murine macrophage cell lines.

Lead inhibited the production of nitric oxide (NO) in cytokine-induced macrophage cell lines of RAW264 and Mm1. The decrease was revealed in the concentration of lead (0.1-10 micrograms/ml) which did not decrease the viability of these cells. The inhibition was proved to be due to the suppression of an inducible type of NO synthase (iNOS) mRNA expression in RAW264 cells. This suppression was found at 24 h and then recovered to the control level (stimulated with cytokine alone) following culture. In the RAW264 cell line, the time course pattern of NO production corresponded to the iNOS mRNA expression. From these results, the inhibition of NO production by, at least in part, mRNA level could be implicated in lead-caused abnormalities in immune functions.

Animals↗
PubMed1996

[Current status of phase I and phase II trials--experience in Habikino from 1988 to 1994].

Introduction of a new agent in the treatment for cancer will require usually three phases of investigation. A new drug will be tested in a small series of patients for toxicity and feasibility; the main objective of a phase I trial is to determine the maximum tolerated dose with a specific type of administration. Demonstration of activity is the major goal of phase II trials, which will place some confidence interval on the efficacy of the new agent. Information obtained from phase I and II studies should be the basis for phase III trials. Based upon our experience with the clinical development of CPT-11, this paper reviews the two factors which influence the quality of the phase I and II trials. Firstly, adequately designed and prepared plans for every clinical trial are essential minimum requirement. Another issue which has been frequently overlooked has been variation from the planned protocol treatment. Such variations can be due to the intolerance of the patient to toxicity as well as the individual physician's poor perceptions and the physician's intolerance of toxicity.

Adult↗
PubMed1996

[Combination phase I trials].

Most successes in the treatment of advanced cancers have required the use of combinations of cytotoxic agents. Therefore, the development of combinations of new active compounds is one of the key challenges of clinical oncology. Reasons for the use of combinations include: 1) biochemical synergism, 2) lack of cross-resistance, and 3) higher achievable dose-intensity by exploiting nonoverlapping dose-limiting toxicities. The first step in clinical development of combinations is to find doses of the drugs that are tolerated when administered together. This is a purpose of a phase I study. However, there are some differences in phase I trials between single agents and combinations. For combinations of drugs, the maximum-tolerated does (MTD) of both active agents is already known. There are almost countless possibilities as to which drugs to combine and in what proportions. A method for selecting drugs and doses for a combination regimen from among many possibilities was discussed in this symposium.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

[Risk of second primary cancer in two-year survivors of small cell lung cancer].

A total of 498 patients with small cell lung cancer received chemotherapy with or without chest irradiation at Osaka Prefectural Habikino Hospital from October 1977 through December 1991. Sixty-one who survived for more than two years were evaluated to determine the incidence and anatomic patterns of redevelopment of small cell lung cancer and development of second primary cancers. The numbers of expected cancers were estimated by cumulating person years of observation from 2 years after the start of treatment for small cell lung cancer to the date of death. Second primary cancers were observed in seven patients (four cases of non-small cell lung cancer, two of gastric cancer, and one of prostate cancer). The risk of a second primary cancer was 3.2 times greater than in the general population (95% Cl: 1.3-6.6). the relations between occurrence of a second primary cancer and family history of cancer, smoking history, smoking cessation after treatment of small cell lung cancer, and thoracic irradiation were studied. Occurrence of a second primary cancer correlated with family history (relative risk 7.5, 95% Cl: 1.5-22) and smoking cessation (relative risk 3.2, 95% Cl: 1.2-6.9). Long-term survivors were more likely to have a second primary cancer than a relapse of small cell lung cancer. Therefore, long-term survivors should be closely monitored for second primary cancers. Meta-analyses of studies done at several institutions may provide more detailed information on the occurrence of second primary cancers after small cell lung cancer.

Adenocarcinoma↗
PubMed1996

[Intra-arterial infusion chemotherapy for liver metastases from breast cancer].

Twelve patients with liver metastases of breast cancer were treated with hepatic arterial infusion chemotherapy using 20-30 mg/body of epi-adriamycin (epi-ADM) every 2 weeks and continuous infusion of 250 mg/body/day of 5-fluorouracil (5-FU). All patients were followed by systemic chemo-endocrine therapy with oral administration of 600-1,200 mg/day of me droxyprogesterone acetate (MPA) alone or with 600-800 mg/day of 5'-deoxy-5-flurouridine (5'-DFUR). The response rate was 41.7% (5/12 cases). Duration of response was 2-28 months (mean 10 months). At one year, the survival rate was 46.8% (Kaplan-Meier method). As for side effects, gastrointestinal disturbance, bone marrow depression and alopecia were mild. These results suggest that hepatic arterial infusion therapy in combination with MPA is safe and effective for controlling liver metastases of breast cancer.

Adult↗
PubMed1995

Abnormal gene product identified in Huntington's disease lymphocytes and brain.

Huntington's disease(HD) is associated with expansion of an unstable CAG repeat. Using antibodies against the synthetic peptide corresponding to the sequence of HD gene IT15, we have identified the HD gene product in normal lymphocytes as a approximately 350kDa protein by immunoblot analysis. Moreover, when a modified SDS-PAGE using a low concentration of methylenbisacrylamide was run longer, abnormal immunoreactive bands larger than normal ones were found exclusively in HD samples. These results demonstrate the existence of the expanded CAG repeat gene product and open a possibility that the expanded polyglutamine stretch may really participate in the pathological process of the CAG repeat diseases.

Amino Acid Sequence↗
PubMed1995

Measurement of cytokeratin 19 fragments as a marker of lung cancer by CYFRA 21-1 enzyme immunoassay.

Soluble cytokeratin fragment 19 levels were measured with an enzyme immunoassay method developed by Boehringer Mannheim (Enzymun-Test CYFRA 21-1) in the serum of 185 patients with lung cancer [149 with non-small-cell lung cancer (NSCLC) and 36 with small-cell lung cancer (SCLC)] and 97 patients with benign lung diseases in order to determine its clinical usefulness in the diagnosis of lung cancer and follow-up of treatment. We used the cut-off value of 3.5 ng ml-1, established by the Japan CYFRA research group. This cut-off value is based on calculations using the receiver operating characteristic approach instead of using the 95% specificity approach recommended by other authors. The resulting sensitivity and specificity for the group of all lung cancer patients were 65.4% and 84.5% respectively. The sensitivity was highest (76.1%) for squamous cell carcinoma and lowest (44.4%) for SCLC. For NSCLC patients, when CYFRA 21-1 levels were analysed by node (N) factor, patients who presented with mediastinal lymph node metastasis (N2 or N3) demonstrated higher serum CYFRA 21-1 levels (5.6; interquartile range 3.2-11.5 ng ml-1) than patients without mediastinal node metastasis (N0 or N1, 3.9; interquartile range 2.2-10.0 ng ml-1; Mann-Whitney U-test, P = 0.0373). We compared the discriminatory power of CYFRA 21-1 with that of other tumour markers including carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC) and neuron-specific enolase (NSE). The area under the curve (AUC) of each ROC curve was calculated using the CLABROC program for statistical analysis. CYFRA 21-1 appeared to have the most discriminatory power of the markers tested in the diagnosis of lung cancer. In serial measurements of 14 patients receiving chemotherapy or radiotherapy, a high degree of correlation was noted between serum levels of CYFRA 21-1 and extent of clinical response (Wilcoxon, P = 0.0093).

Adult↗
PubMed1995

Relationship between the pharmacokinetics of irinotecan and diarrhea during combination chemotherapy with cisplatin.

Two phase I trials of irinotecan (CPT-11) in combination with cisplatin were conducted. In both cases, the dose-limiting toxicities were leukopenia and/or diarrhea. During these trials the pharmacokinetics of CPT-11 and its active metabolite, 7-ethyl-10-hydroxycamptothecin (SN-38), were investigated to evaluate the relationship between pharmacokinetic parameters and diarrhea, since this is an unpredictable and severe toxicity of combination chemotherapy using CPT-11 and cisplatin. Twenty-three previously untreated patients with advanced lung cancer were evaluated in the pharmacokinetic study. Ten patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 60 mg/m2. The other 13 patients received CPT-11 at 80 or 90 mg/m2 plus cisplatin at 80 mg/m2 with the granulocyte colony-stimulating factor support (2 micrograms/kg x 16 days). CPT-11 was given as a 90-min intravenous infusion on days 1, 8, and 15. Cisplatin was given on day 1. The pharmacokinetics of CPT-11 and SN-38 were analyzed on day 8 during the first course of treatment. The maximum tolerated dose of CPT-11 was 90 mg/m2 in both phase I trials. The severity of diarrhea was best correlated with the peak plasma concentration of SN-38 among the pharmacokinetic parameters tested. In addition, patients with a plasma SN-38 level > 12.4 ng/ml at 1.75 h after the start of CPT-11 infusion had a higher incidence of Eastern Cooperative Oncology Group grade 3-4 diarrhea than those with a lower SN-38 level (P = 0.0003). Stepwise logistic regression analysis identified the SN-38 concentration as a significant contributor to the development of diarrhea (P = 0.0021). We conclude that there is a clear relationship between the SN-38 concentration and diarrhea during chemotherapy with CPT-11 plus cisplatin.

Adult↗
PubMed1995

Outer membrane proteins responsible for multiple drug resistance in Pseudomonas aeruginosa.

Three types of multiple-drug-resistant mutants which were phenotypically similar to previously described nalB, nfxB, and nfxC mutants were isolated from Pseudomonas aeruginosa PAO1 and two clinical isolates. Type 1 (nalB-type) mutants showed cross-resistance to meropenem, cephems, and quinolones. They overproduced an outer membrane protein with an apparent molecular mass of 50 kDa (OprM). Type 2 (nfxB-type) mutants showed cross-resistance to quinolones and new cephems, i.e., cefpirome and cefozopran, concomitant with overproduction of an outer membrane protein with an apparent molecular mass of 54 kDa (OprJ). Type 3 (nfxC-type) mutants showed cross-resistance to carbapenems and quinolones. They produced decreased amounts of OprD and increased amounts of a 50-kDa protein (OprN), which was almost the same molecular weight as that of OprM, but it was distinguishable from OprM by its heat modifiability on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the presence of salicylate, the parent strains showed an increased level of resistance to carbapenems and quinolones and produced decreased amounts of OprD and increased amounts of OprN. Salicylate caused the repression of OprJ production and the loss of resistance to cefpirome and cefozopran in two of the three OprJ-overproducing mutants, although salicylate slightly increased the level of resistance in the parent strains. The changes in susceptibilities were transient in the presence of salicylate. These data suggest that at least three different outer membrane proteins, OprM, OprJ, and OprN, are associated with multiple drug resistance in P. aeruginosa.

Anti-Bacterial Agents↗
PubMed1995

Analysis of triplet repeats in the huntingtin gene in Japanese families affected with Huntington's disease.

Huntington's disease (HD) is associated with the expansion of a CAG repeat in the huntingtin gene. Molecular analysis of the repeat in Japanese HD patients and normal controls was performed. The size of the CAG repeat ranged from 37 to 95 repeats in affected subjects and from seven to 29 in normal controls. A significant correlation was found between the age of onset and the CAG expansion. The length of the expanded repeat is unstable in meiotic transmission and large increases occur in paternal transmission. At the same time the CCG repeat polymorphism adjacent to the CAG repeat was analysed and haplotypes of HD chromosomes were identified. Strong linkage disequilibrium was found between the CAG repeat expansion and an allele of (CCG)10 in Japanese HD chromosomes. It is distinct from that described previously in western populations. Western HD chromosomes strongly associate with an allele of (CCG)7. Possible mechanisms underlying the disequilibrium in Japan are discussed.

Age of Onset↗
PubMed1995

Male reproductive toxicity study of nitrazepam in rats.

The main focus of this study is the optimal administration period concerning toxic effects on male fertility in rats. To assess functional and morphological changes induced in the testis by nitrazepam, male rats were administered the drug at doses of 0, 20, 40 or 80 mg/kg during pre-mating periods of 2, 4 or 9 weeks and then the 2 weeks of mating. At the end of the administration period the animals were sacrificed and sperm number, motility, abnormalities and histopathological changes in the testis were examined. Decreases in testis weight, epididymis weight, number of sperm in the testis and sperm motility were observed in the 40 and 80 mg/kg sections of the 2, 4 and 9 week pre-mating treated groups. Mating with untreated females revealed no adverse effects on copulation rate in any group; however, a remarkable decrease in pregnancy rate was noted in the 80 mg/kg section of the 2, 4 and 9 week treated groups. On histological examination, various degrees of localized necrosis in the seminiferous epithelium and Leydig cell hyperplasia were observed in the testis. No clear changes were observed in the 20 mg/kg section of the 2 week pre-mating administration group, but at the 4 week time point, necrosis of spermatogenic cells began to appear. The primary morphological event was evident in spermatocytes with necrosis of the cytoplasm observed from 4 weeks after administration of nitrazepam, although sperm motility and sperm head counts were unaffected. From these findings, examination of sperm characteristics and histopathological changes in the testis are important parameters for evaluation of drugs inducing testicular damage. We conclude that a 4 week administration period is sufficient to detect effects of nitrazepam on male fertility.

Animals↗
PubMed1995

Significance of serum neuron-specific enolase as a predictor of relapse of small cell lung cancer.

We conducted a prospective study to evaluate the significance of serum neuron-specific enolase (NSE) as a predictor of relapse of small cell lung cancer (SCLC). Patients entered into the study were drawn from those who had shown a complete or partial response to first-line chemotherapy with a concurrent decline in the NSE level to less than 10 ng/ml. When the serum NSE level increased to more than 15 ng/ml, the patient was restaged on the basis of clinical, radiological, and bronchoscopic examinations. During the period from August 1988 to December 1990, 57 patients with SCLC were enrolled and followed up until May 1992. Of these patients, 45 had clinical relapses, and 14 (31%) of them showed a clear elevation of the serum NSE level prior to the clinical recognition of relapse. Although one false-positive case was noted, this involved only a transient elevation of the NSE level. In patients who showed increased NSE levels, the relapses occurred in more difficult to detect silent sites such as the adrenal gland, liver, and deep lymph nodes. In addition, the percentage of patients demonstrating high NSE levels who were able to benefit from salvage chemotherapy was higher than for those who did not (RHO < 0.05). Our results indicate that serial NSE measurements are useful for the early prediction of SCLC relapse and should help to facilitate early administration of salvage chemotherapy for affected patients.

Adult↗
PubMed1995

Effect of the potassium channel opener YM934 on the contractile response to electrical field stimulation in pig detrusor smooth muscle.

PURPOSE: The effect of a potassium channel opener, YM934, on the contractile response to excitatory neurotransmitters was investigated in isolated pig detrusor smooth muscle. MATERIALS AND METHODS: Electrical field stimulation (EFS; 5 second trains, 50 V, 0.8 msec. duration), alpha, beta-MeATP (3 x 10(-7) to 10(-5) M.) or carbachol (3 x 10(-8) to 10(-6) M.) produced a contractile response in isolated pig detrusor smooth muscle. The effect of YM934 on the contractile responses was evaluated in comparison with the antagonism of the putative cotransmitters, acetylcholine and ATP. RESULTS: A tetrodotoxin-sensitive, frequency-dependent contractile response to electrical field stimulation was obtained. Atropine (3 x 10(-8) M.) significantly inhibited the contractile response at high frequencies, whereas alpha, beta-MeATP (5 x 10(-6) M.) (desensitizer of P2X-purinoceptors) significantly inhibited the response at low frequencies. YM934 (10(-8) to 10(-7) M.) dose-dependently inhibited the nerve-mediated contractile responses to all frequencies but preferentially at low frequencies, by analogy with alpha, beta-MeATP. A combination of YM934 (3 x 10(-8) M.) and atropine (3 x 10(-8) M.) reduced the response at all frequencies to between 10 and 20% of control, an effect similar to that obtained with alpha, beta-MeATP (5 x 10(-6) M.) and atropine (3 x 10(-8) M.). In addition, YM934 (3 x 10(-8) M.) markedly inhibited the contractile response induced by exogenously applied alpha, beta-MeATP (3 x 10(-7) to 10(-5) M.) but only slightly inhibited the contractile response induced by exogenously applied carbachol (3 x 10(-8) to 10(-6) M.). CONCLUSION: These results suggest that YM934 may hyperpolarize the membrane of pig detrusor smooth muscle through the opening of ATP-sensitive potassium channels and, as a result, may functionally inhibit the contractile response to purinergic nerve stimulation that elicits the membrane depolarization.

Adenosine Triphosphate↗
PubMed1995

[Phase III trial of new anticancer agents from a medical oncologists viewpoint].

The purpose of a phase III study is to establish the efficacy of a new agent (whether it is a single-agent, a combination of drugs or a combined modality approach) compared with the best conventional treatment. Several cytotoxic agents with promising single-agent activity in non-small cell lung cancer have recently been defined. Among them are Navelbine, taxol, taxotere, CPT-11 and gemcitabine. A phase III study of Navelbine has been completed. A study is currently in progress defining activity for taxol in combination with cisplatin. Several aspects in designing a phase III trial of CPT-11 related to the efficiency were discussed, with particular emphasis on the following points considered particularly important, timely, or relevant to this symposium. Firstly, the value of a clinical trial is determined mostly by the importance of the question addressed. After the question of timing has been resolved, the choice of the test and appropriate control treatments is central. The keys to obtaining a reliable answer are the use of randomized treatment allocation, adequate sample size, good data quality, protocol adherence, sufficient follow-up, avoidance of exclusions, appropriate analysis, and lack of data dredging. Participation of a biostatistician is also indispensable for improving the efficiency of comparative clinical trials.

Antineoplastic Agents↗