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Biomedical subjects

M Masutani

Publications and source records attributed to M Masutani.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effect of Tween-80 on cell killing by etoposide in human lung adenocarcinoma cells.

PURPOSE: The non-ionic detergent Tween-80, a surface-active agent, has been shown to modulate the cytocidal effect of certain antitumor agents. In the present study, we sought to determine whether or not Tween-80 could enhance the antitumor effect of etoposide (VP16) in human lung cancer cells in vitro. METHODS: Survival fractions were measured by growth inhibiton assays of PC14, H69, KB, and PC14/CDDP (the corresponding cisplatin-resistant subline of PC14) cells. An in vitro clonogenic assay of PC14 and PC14/CDDP cells was undertaken after incubation for 10-12 days in RPMI-1640 medium with 20% fetal calf serum and 1.72% methyl cellulose, plus continuous exposure to VP16 with Tween-80. We also investigated the direct toxicity of Tween-80 to PC14 and PC14/CDDP cells using a clonal assay. The intracellular accumulation of VP16 was further analyzed using [3H]VP16 in PC14, PC14/CDDP, A549, KB and H69 cells, and compared with that of daunorubicin (DNR), a hydrophilic anti-cancer agent, using [3H]DNR in PC14, A549 and KB cells. RESULTS: It was found that PC14/CDDP had collateral sensitivity to VP16 and Tween-80 markedly enhanced the killing effect of VP16 not only of PC14 cells but also of PC14/CDDP cells while exerting little cytotoxic effect. Moreover, Tween-80 increased the intracellular accumulation of VP16 in PC14, PC14/CDDP and A549 cells, and not in KB and H69 cells. Tween-80 did not increase the intracellular DNR levels in PC14, A549 and KB cells. CONCLUSIONS: Tween-80 was shown to potentiate the cytotoxicity of VP16 against several human lung adenocarcinoma cells by increasing the accumulation of VP16 in vitro. Tween-80-mediated sensitization of lung adenocarcinoma cells to VP16 is considered to be related to both the characteristics of the cell membrane in adenocarcinoma cells and the lipotropic properties of VP16. These results suggest that this combination might have the potential to improve the therapeutic index of VP16 in human lung adenocarcinoma.

Adenocarcinoma↗
PubMed1999

Isolation and cloning of rat poly(ADP-ribose) glycohydrolase: presence of a potential nuclear export signal conserved in mammalian orthologs.

Poly(ADP-ribose) glycohydrolase (Parg) is the main enzyme of poly(ADP-ribose) degradation. To understand its structure-and-function relationship, we purified Parg from rat testis 9,740-fold using an improved affinity column; the purified product was a 60 kDa protein. Based on the determined sequences of three peptide fragments, degenerated primers were synthesized and a Parg cDNA comprising 3,974 nucleotides, encoding a 109 kDa protein, was isolated. The 60 kDa Parg purified from rat testes corresponded to the C-terminal half of the 109 kDa deduced peptide. When recombinant rat Parg was expressed as a glutathione S-transferase fusion protein in Escherichia coli, Parg activity was observed for the full-length and C-terminal half proteins but not in for the N-terminal half protein. Taken together, these data indicate that the catalytic domain of Parg is located in the C-terminal half. Further, we newly identified the presence of a potential nuclear export signal in the N-terminal half in addition to the previously reported nuclear localization signals in rat and other mammalian Pargs. Northern blot analysis showed the ubiquitous expression of a single 4.0 kb Parg mRNA in various rat tissues. The findings suggest that the 60 kDa Parg is produced by post-transcriptional processing.

Amino Acid Sequence↗
PubMed1999

Phase II study of area under the plasma-concentration-versus-time curve-based carboplatin plus standard-dose intravenous etoposide in elderly patients with small-cell lung cancer.

PURPOSE: The target area under the plasma-concentration-versus-time curve (AUC)-based dosing of carboplatin using Calvert's formula is expected to result in more acceptable toxicity and greater efficacy in elderly patients with small-cell lung cancer (SCLC) than the body surface area-based dosing strategy. This phase II study was designed to determine the toxicity and efficacy of carboplatin based on Calvert's formula plus the standard dose of intravenous etoposide for elderly patients with SCLC. PATIENTS AND METHODS: Carboplatin, dosed to a target AUC of 5 x (24-hour creatinine clearance + 25), was given intravenously on day 1 and etoposide 100 mg/m(2) was given intravenously on days 1, 2, and 3. Patients aged >/= 70 years old with a performance status of 0 to 2 were eligible. RESULTS: Thirty-six patients were enrolled onto the study. The patient characteristics were as follows: median age, 73 years; limited disease (LD), 16 patients; and extensive disease (ED), 20 patients. Grades 3 and 4 leukopenia occurred in 57% and 3% of patients, and grades 3 and 4 thrombocytopenia occurred in 40% and 11% of patients, respectively. There was one treatment-related death due to hemoptysis. Other toxicities were relatively mild. There were two complete responses and 25 partial responses, for a response rate of 75%. The median survival time was 10.8 months (LD, 11.6 months; ED, 10.1 months), and the 1-year survival rate was 47%. CONCLUSION: This carboplatin/etoposide combination chemotherapy is an active and relatively nontoxic regimen in elderly patients with SCLC, which suggests that the combination may be suitable for randomized controlled trials.

Aged↗
PubMed1999

A decrease in the amount and function of inhibitory GTP-binding protein in the resistance small artery from spontaneously hypertensive rats.

The inhibitory GTP-binding protein (Gi protein) plays an important role in regulation of vascular tone. Many studies have implicated the role of Gi protein in conduit vessels. However, the physiological role of Gi protein in the control of peripheral microvascular tone in hypertension has not been established yet. Therefore, we investigated the concentration of Gi protein in the peripheral resistance arteries and aorta in the spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY) and renovascular hypertensive rats (RHR), using immunohistochemical methods semiquantitatively. Changes in the function of Gi protein in relation to alpha2-adrenoceptor were also investigated by microcannulation techniques. We have shown that the amount of alpha2 subunits of Gi protein in the cremaster small artery was significantly lower in SHR aged 4 weeks and older than in age-matched WKY and that there were no significant differences between RHR and WKY. We also demonstrated that the function of Gi protein in relation to alpha2-adrenoceptor was already lower in SHR before the onset of hypertension. The quantitative and functional decline in Gi protein in the smooth muscle cells of peripheral small arteries were observed in SHR even before the onset of hypertension, whereas rats with secondary hypertension did not exhibit this finding.

Aging↗
PubMed1999

Evaluation of expression of CD15 and sCD15 in non-small cell lung cancer.

Changes in cell membrane carbohydrate antigens play an important role in metastatic potential associated with carcinogenesis and in prognostic factors. We investigated immunohistochemically the expression of CD15 and sialyl CD15 (sCD15) in lung cancer tissue by using Leu-M1 antibody and MXKM-93 antibody, respectively, and then assessed the relationship between their expression and the patient outcome. Lung cancer tissue expression of CD15 was significantly higher in adenocarcinoma (55.9%) and squamous cell carcinoma (44.7%) than in small cell carcinoma (10%) (p=0.01, p=0.006). Expression of sCD15 was significantly higher in adenocarcinoma (52.9%) than in squamous cell carcinoma (10.5%) or small cell carcinoma (10%) (p<0. 0001, p=0.016). No association was found between CD15 expression and clinical stage, but sCD15 expression increased with clinical stage (stage I+II vs. III+IV: 16.7% vs. 39.6%; p=0.049). Expression of CD15 (1.5%) was significantly lower than expression of sCD15 (12.3%) in normal surrounding tissue. Examination of associations with outcome in NSCLC revealed that expression of sCD15 in resected cases, and expression of CD15 in non-resected cases were significantly correlated with shortening of median survival time (p<0.05). When associations with prognostic factors were assessed by univariate analysis, expression of sCD15 was found to be correlated with distant metastasis, and expression of CD15 with decrease in performance status (PS). In the multivariate analysis by the Cox proportional hazard model, sCD15 and CD15 negativity contributed to longer survival time after PS and clinical stage. The results of a combination assay of CD15 and sCD15 showed that expression of both carbohydrate antigens significantly shortened survival time in both the resected and non-resected group (log-rank test, p<0.05). This combination assay also appeared to be extremely useful in predicting the outcome in all clinical stages of NSCLC.

Adenocarcinoma↗
PubMed1999

Function of poly(ADP-ribose) polymerase in response to DNA damage: gene-disruption study in mice.

To elucidate the biological functions of poly(ADP-ribose) polymerase (PARP, [EC 2.4.2.30]) in DNA damage responses, genetic and biochemical approaches were undertaken. By disrupting exon 1 of the mouse PARP gene by a homologous recombination, PARP-deficient mouse embryonic stem (ES) cell lines and mice could be produced without demonstrating lethality. PARP-/- ES cells showed complete loss of PARP activity and increased sensitivity to gamma-irradiation and an alkylating agents, indicating a physiological role for PARP in the response to DNA damage. p53, a key molecule in cellular DNA damage response, was found to stimulate PARP activity and became poly(ADP-ribosyl)ated in the presence of damaged DNA. However, PARP-/- ES cells showed p21 and Mdm-2 mRNA induction following gamma-irradiation, indicating that PARP activity is not indispensable for p21 and Mdm-2 mRNA induction in the established p53-cascade. On the other hand, in a reconstituted reaction system, purified PARP from human placenta suppressed the pRB-phosphorylation activity in the presence of NAD and damaged DNA. Human PARP expressed in E. coli showed a similar effect on pRB-phosphorylation activity of cdk2. These findings suggest a direct involvement of PARP in the regulation of cdk activity for cell-cycle arrest.

Animals↗
PubMed1998

In vivo phosphorylation of poly(ADP-ribose) polymerase is independent of its activation.

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme, which is activated by DNA strand breaks. Although PARP is known to be cleaved by the cysteine protease, caspase-3/CPP32, during apoptosis, signal cascade which regulates the PARP activity has not been fully understood. In this study, we investigated post-translational modification of PARP. We found that PARP was phosphorylated by a serine kinase in vivo. PARP was activated temporarily and extensive auto-modification occurred on PARP, possibly by the fragmented DNA during apoptosis induced by etoposide in Jurkat cells. However, the phosphorylation level was not changed for up to 6 h, after PARP cleavage began in apoptosis by the treatment with etoposide. Furthermore, we showed the presence of a PARP-associated kinase in nuclear extracts of the HTLV-I infected T-cell lines but not in uninfected T-cell lines, whereas this kinase did not inhibit the PARP activity even in the presence of ATP. Taken together, in vivo phosphorylation of PARP might be independent of the activation or cleavage of PARP.

Cell Line↗
PubMed1998

The human poly(ADP-ribose) glycohydrolase maps to chromosome 10q11.23-21.1 by fluorescence in situ hybridization.

Poly(ADP-ribose) glycohydrolase (PARG) digests poly(ADP-ribose), which is synthesized by poly(ADP-ribose) polymerase (PARP) after DNA damage. We mapped the human poly(ADP-ribose) glycohydrolase gene to chromosome 10q11.23-21.1 by fluorescence in situ hybridization analysis. Since chromosomal rearrangements in thyroid papillary carcinoma and loss of heterozygosity in glioblastoma are frequently observed in this region, genetic alteration of PARG could be implicated in these diseases.

Base Sequence↗
PubMed1998

[Changes of 24-h Holter monitor recordings in association with interferon alpha therapy for chronic hepatitis C].

We examined cardiovascular complication of interferon (IFN) therapy in 23 patients with chronic hepatitis C who did not have cardiac disease prospectively. Twenty four-h Holter monitor recordings were performed before and during IFN therapy. Seven of these patients (30%) showed abnormalities on their 24-h Holter monitoring recordings. Premature ventricular contraction (PVC) occurred in two patients, intermittent WPW syndrome in one, and ST-T change in four. Only one patient with PVC complained of palpitation. These complications were not severe and immediately after IFN therapy was stopped. There was no correlation between Holter ECG abnormalities and sex, age, quantity of HCV, or 2-5 oligoadenylate synthetase activity. It was suggested that cardiovascular complications caused by IFN therapy occurred more frequently than expected. However, diagnosis of these complications is difficult because most patients have no subjective symptoms and there is scarcely any change in laboratory test results. Careful observation of patients may be required during IFN therapy regardless of cardiovascular symptoms.

Adult↗
PubMed1997

Requirement of the caspase-3/CPP32 protease cascade for apoptotic death following cytokine deprivation in hematopoietic cells.

Hematopoietic cytokines transduce cell survival signals, which are distinct from the signals necessary for the stimulation of DNA synthesis. Recently, the Ras and phosphatidylinositol 3-kinase pathways have been shown to play important roles in preventing apoptosis in various cell types, e.g. hematopoietic cells and neuronal cells. Withdrawal of cytokine(s), in turn, results in rapid inactivation of these survival pathways and eventually leads to cell death accompanied by the hallmarks of apoptosis. However, the mechanism of cell death caused by cytokine deprivation has not been fully elucidated. In this study, we demonstrate that caspase-3/CPP32, a member of the caspase/interleukin-1beta-converting enzyme family, is activated upon interleukin (IL)-3 deprivation in IL-3-dependent cells as well as IL-2 deprivation in IL-2-dependent cells. In addition, poly(ADP-ribose) polymerase, a cellular substrate for the caspase family proteases, was degraded into apoptotic fragments in both cell lines after cytokine removal. Furthermore, inhibition of a caspase family protease by synthetic peptides suppressed apoptotic death. These results indicate that the activation of a caspase-like protease(s) is required for the progression of apoptosis following cytokine deprivation. However, readdition of IL-3 did not restore the proliferative potential of the cells that survived in the presence of the peptide inhibitor after IL-3 depletion. Therefore, cellular commitment to apoptosis appears to precede the activation of a caspase-like protease(s).

Animals↗
PubMed1997

Abrogation of G1 arrest after DNA damage is associated with constitutive overexpression of Mdm2, Cdk4, and Irf1 mRNAs in the BALB/c 3T3 A31 variant 1-1 clone.

A search of cell lines showing aberrant cell-cycle checkpoints revealed the lack of gamma-irradiation-induced G1 arrest in the BALB/c 3T3 A31 variant 1-1 (A31-1-1) clone. This clone is well-known for its hypersensitivity to transformation by DNA damaging agents. p53 stabilization and p21 mRNA induction after 8 Gy irradiation were observed, suggesting that the abrogation of G1 arrest occurred in spite of normal p53 and p21 responses by abnormal regulation of other cellular factors. Constitutive overexpression of Mdm2 and Cdk4 mRNAs was found, which might have contributed to the loss of G1 arrest. In addition, overexpression of a growth-suppressive transcription factor, Irf1, a putative key molecule in the p53-independent pathway after DNA damage, was also observed, although the relation to the loss of G1 arrest could not be elucidated.

3T3 Cells↗
PubMed1997

Helicobacter pylori extracts exhibit nicotinamide adenine dinucleotide-derived adenylation but not mono(adenosine 5'-diphosphate-ribosyl)ation of DNA ligase.

The issue of toxins produced by Helicobacter pylori (H. pylori) urgently requires clarification given that the bacterium causes gastric epithelial cell damage which may lead to precancerous and cancerous changes. During an investigation of the possibility of mono(adenosine 5'-diphosphate (ADP)-ribosyl)ation by H. pylori products, as observed for other bacterial toxins, we found that radioactivity of [adenylate-32P]nicotinamide adenine dinucleotide (NAD) is incorporated into an H. pylori protein of 80 kDa after incubation with crude bacterial extract. In contrast, [carbonyl-14C]NAD did not show any radioactivity incorporation. Unexpectedly, treatment of the modified protein with 0.1 N HCl, but not 0.1 N NaOH, released the AMP moiety. Such chemical properties are characteristic of bacterial DNA ligase-AMP complexes. We found that an antibody raised against Escherichia coli DNA ligase [EC 6.5.1.2] immunoprecipitated the modified 80 kDa protein. Our results indicate that incorporation of radioactivity derived from NAD into the 80 kDa protein was due to adenylation, but not mono(ADP-ribosyl)ation, of the DNA ligase of H. pylori.

Adenosine Diphosphate Ribose↗
PubMed1996

Presence in Pieris rapae of cytotoxic activity against human carcinoma cells.

Cytotoxic activity in extracts of pupae and adults of various kinds of butterflies and moths was tested in vitro against the human gastric carcinoma cell line, TMK-1, which was chosen as an example of human carcinoma cells. Among the species examined, cytotoxicity was limited to Pieris rapae, Pieris napi and Pieris brassicae. Activity was found down to a dilution of 1/10(4), while with the other butterflies and moths no activity was observed, even at 1/10(2). When the cytotoxicity of the three developmental stages, larvae, pupae and adults, of Pieris rapae was compared, the pupae showed the strongest activity, the IC50 against TMK-1 cells being at the 1/10(6) dilution. For larvae and adults, the respective IC50 values were at the 1/10(5) and 5/10(5) dilutions. The active principle in the pupae of Pieris rapae was found to be heat-labile and not extractable with organic solvents, but precipitated with ammonium sulfate and digested by proteases, suggesting that it is a protein. This cytotoxic factor was named pierisin.

Animals↗
PubMed1996

A phase III randomized trial of cisplatin plus vindesine versus cisplatin plus vindesine plus mitomycin C versus cisplatin plus vindesine plus ifosfamide for advanced non-small-cell lung cancer.

A randomized trial of chemotherapy in 105 patients with advanced and metastatic non-small-cell lung cancer (NCSLC) was conducted in order to compare the effect of the additional drug mitomycin C (PVM) or ifosfamide (PVI), to the combination of cisplatin plus vindesine (PV). An objective response rate was observed in 42.8% of the patients treated with PVM, 42.4% with PVI and 28.6% with PV and these response rates were not statistically significant (P > 0.20). No patient achieved the complete response with either of the three regimens. Comparison of the median response durations among the three regimens showed an advantage of PVI over PVM (P < 0.02) and PV (P < 0.05). The median survival times (MST) were similar for all three regimens (PVM, 33.5; PVI, 40.0 and PV, 36.5 weeks); moreover, the difference in survival time between the three regimens of responders was not statistically significant. The univariate analysis showed that significant predictors of survival were performance status (PS) zero (P = 0.0002), limited disease (P = 0.004), no previous weight loss (P = 0.01) and normal serum albumin (P = 0.016), and in multivariate analysis by a stepwise Cox proportional hazard model, these were PS zero (a hazard ratio of 2.3, P = 0.0001) and limited disease (a hazard ratio of 1.9, P = 0.048). Toxicity did not differ among the three treatment regimens.

Aged↗
PubMed1996

[Clinical evaluation of fiberoptic bronchoscopy for the diagnosis of solitary pulmonary nodules 2 cm or less in diameter of chest roentgenogram].

The value of fiberoptic bronchoscopy in the diagnosis of solitary pulmonary nodules was studied. The subjects were 59 patients with chest-roentgenographic evidence of a solitary pulmonary nodule 2 cm or less in diameter. Definitive diagnoses were made in 34 patients (57.6%). Primary lung care was diagnosed 21 of 32 patients (65.6%), pulmonary tuberculosis in 7 of 12 (58.3%), metastatic lung cancer in 3 of 5 (60%), old lesions in 3 of 5 (60%), and pulmonary filariasis in 0 of 1 (0%). The diagnostic sensitivity of transbronchial biopsy was superior to that of curettage, and combining the two techniques further improved the diagnostic yield. Bronchial lavage was not effective for diagnosis of lung cancer, but was effective for diagnosis of pulmonary tuberculosis. Diagnostic yield was less for nodules in upper lobes than for those in other lobes, and most malignant tumors that were not diagnosed from the results of fiberoptic bronchoscopy were in upper lobes. We conclude that combining various fiberoptic bronchoscopic procedures can improve the diagnostic yield in patients with small pulmonary nodules. CT-guided needle biopsy and video-assisted thoracoscopic biopsy are two such procedures. Early diagnosis of small pulmonary nodules requires a skilled bronchoscopist who can choose the most appropriate method for biopsy.

Bronchoscopy↗