Biomedical subjects

J Fujita

Publications and source records attributed to J Fujita.

At least 19 recordsLinked to original sources

PubMed1997

A glycine-rich RNA-binding protein mediating cold-inducible suppression of mammalian cell growth.

In response to low ambient temperature, mammalian cells as well as microorganisms change various physiological functions, but the molecular mechanisms underlying these adaptations are just beginning to be understood. We report here the isolation of a mouse cold-inducible RNA-binding protein (cirp) cDNA and investigation of its role in cold-stress response of mammalian cells. The cirp cDNA encoded an 18-kD protein consisting of an amino-terminal RNAbinding domain and a carboxyl-terminal glycine-rich domain and exhibited structural similarity to a class of stress-induced RNA-binding proteins found in plants. Immunofluorescence microscopy showed that CIRP was localized in the nucleoplasm of BALB/3T3 mouse fibroblasts. When the culture temperature was lowered from 37 to 32 degrees C, expression of CIRP was induced and growth of BALB/3T3 cells was impaired as compared with that at 37 degrees C. By suppressing the induction of CIRP with antisense oligodeoxynucleotides, this impairment was alleviated, while overexpression of CIRP resulted in impaired growth at 37 degrees C with prolongation of G1 phase of the cell cycle. These results indicate that CIRP plays an essential role in cold-induced growth suppression of mouse fibroblasts. Identification of CIRP may provide a clue to the regulatory mechanisms of cold responses in mammalian cells.

3T3 Cells↗

PubMed1997

Cloning of apg-2 encoding a novel member of heat shock protein 110 family.

Chinese hamster heat shock protein 110-encoding gene (hsp110), mouse apg-1 and human hsp70RY are structurally related genes, with the first two encoding about 110-kDa HSPs [Yoon et al. (1995) J. Biol. Chem. 270, 15725-15733; Kaneko et al. (1997) J. Biol. Chem., in press; Fathallah et al. (1993) J. Immunol. 151, 810-813]. Using apg-1 cDNA as a probe, we isolated a novel cDNA, apg-2 from a mouse testis cDNA library, which was highly homologous to human hsp70RY. However, the predicted amino acid (aa) sequence of APG-2 was longer (841 aa) than that of HSP70RY (701 aa) and comparable to those of HSP110 and APG-1. Northern blot analysis revealed that the expression of apg-2 transcripts was ubiquitous in various mouse tissues, and most abundant in the testis and ovary. While induction of hsp70 transcripts was observed in mouse TAMA26 Sertoli cells and NIH/3T3 fibroblasts on temperature shift from 37 degrees C to 42 degrees C (traditional heat shock) or from 32 degrees C to 39 degrees C, apg-2 transcripts were not induced under either condition. These results suggest that apg-2 is an isoform of mouse homolog of hsp70RY, but that it belongs to the hsp110 family instead of hsp70 family, and that it plays a role under non-stress conditions.

Amino Acid Sequence↗

PubMed1997

CYP1A1, CYP2E1 and GSTM1 polymorphisms are not associated with susceptibility to squamous-cell carcinoma of the esophagus.

We investigated the genetic polymorphisms of CYP1A1, CYP2E1 and GSTM1 in Japanese esophageal cancer patients (n = 53) with a histological diagnosis of squamous-cell carcinoma, to determine whether susceptibility to esophageal cancer is associated with these polymorphisms. There were no significant differences in the frequency distribution of any one of the 3 polymorphisms between esophageal cancer patients and 132 healthy Japanese controls. The genotype distributions in tobacco smokers or alcohol drinkers were also quite similar for male patients and male controls. The age at onset of esophageal cancer was also similar for patients with any genotype of the 3 polymorphisms. We conclude that the 3 polymorphisms are unlikely to be associated with esophageal cancer susceptibility.

Adult↗

PubMed1997

Developmentally regulated expression of APG-1, a member of heat shock protein 110 family in murine male germ cells.

Apg-1 encodes a heat shock protein belonging to the heat shock protein 110 family, and is inducible by a 32 degrees C to 39 degrees C heat shock. Northern blot analysis of the testis from immature and adult mice, and of the purified germ cells revealed the quantitative change of the apg-1 transcripts during germ cell development. By in situ hybridization histochemistry the expressions of the apg-1 transcripts were detected in germ cells at specific stages of development including spermatocytes and spermatids. Although heat-induction of the apg-1 transcripts was observed in W/Wv mutant testis lacking germ cells, it was not detected in wild-type testis nor in the purified germ cells. Thus, the apg-1 expression is not heat-regulated but developmentally regulated in germ cells, suggesting that APG-1 plays a role in normal development of germ cells.

Animals↗

PubMed1997

Expression of a novel isoform of Vav, Vav-T, containing a single Src homology 3 domain in murine testicular germ cells.

Vav is a signal transducing molecule containing C-terminal Src homology 3 (SH3)-SH2-SH3 domains, and has been thought to be expressed exclusively in hematopoietic and trophoblastic cells. By Northern blot analysis, vav transcripts of unique sizes, 4.8 kb and 1.0 kb, were detected in the testis among various tissues examined. From a mouse spermatocyte cDNA library, a novel isoform of vav (vav-T) was cloned, which corresponded to a part of the 4.8 kb transcript. Vav-T had an alternative 5' sequence up to the middle of SH2-coding region, and encoded 163 amino acids with a single SH3 domain. Northern blot analysis of fractionated testicular cells and in situ hybridization histochemistry demonstrated that vav-T transcripts were expressed in the differentiating germ cells, especially spermatocytes. A 24 kD protein was detected by anti-Vav antibodies in the testis, but not in the spleen or bone marrow. Transcripts of heterogeneous nuclear ribonucleoprotein K, known to associate with the most C-terminal SH3 domain of Vav, were also detected in the differentiating male germ cells. These results demonstrate expression of previously nondescribed Vav-isoform in the testicular germ cells, and suggest that it interacts with RNA-binding proteins and plays an important role in spermatogenesis.

Amino Acid Sequence↗

PubMed1997

A novel hsp110-related gene, apg-1, that is abundantly expressed in the testis responds to a low temperature heat shock rather than the traditional elevated temperatures.

We isolated a novel hsp110-related gene, apg-1, from a testis cDNA library. The apg-1 transcripts were constitutively expressed in the testicular germ cells and, in some degree, most tissues examined. In a mouse TAMA26 Sertoli cell line, apg-1 transcripts were induced in 2 h by a temperature shift from 32 to 39 degrees C, but not by a shift from 37 to 42 degrees C, the traditional heat stress, or a shift from 32 to 42 degrees C. The heat response pattern of hsp110 expression was similar to that of apg-1. Although induction of a hsp70 transcript was observed in 2 h by a shift from 32 to 39 degrees C, the induction was more apparent by a shift from 37 to 42 degrees C or from 32 to 42 degrees C. Essentially similar differential response patterns were observed among these genes in NIH/3T3 fibroblasts as well. The nuclear run-on assay and the native gel mobility shift assay demonstrated that, by the 32 to 39 degrees C temperature shift, the apg-1 gene was transcriptionally activated, and heat shock factor 1 bound to the heat shock elements in the 5'-flanking region of the apg-1 gene. These results demonstrated that expressions of apg-1, hsp110, and hsp70 could be heat-induced at a temperature lower than the traditional elevated temperatures in somatic cells of both testis and nontestis origin and suggest that the mechanisms regulating the transcript levels of apg-1 and hsp110 are different from those of hsp70. Furthermore, the constitutive expression in germ cells suggests that APG-1 plays a specific role in spermatogenesis as well as in stress response.

3T3 Cells↗

PubMed1997

Decreased expression and rare somatic mutation of the CIP1/WAF1 gene in human hepatocellular carcinoma.

CIP1/WAF1, a critical downstream effector of tumor suppressor p53, encodes a cyclin-dependent kinase inhibitor. By Northern blot analysis, the CIP1/WAF1 mRNA level in the tumor was significantly lower than that in the corresponding normal liver from 19 Japanese patients with hepatocellular carcinoma (P < 0.05). In the tumor from only one out of 19 patients (5%), somatic mutations of the CIP1/WAF1 as well as that of p53 gene were identified by RT-PCR/SSCP analysis. These results suggest that the decreased CIP1/WAF1 expression is involved in the carcinogenesis or the progression of hepatocellular carcinoma.

Adult↗

PubMed1997

Nisoldipine blocks the increase of intracellular free calcium-ion concentration associated with elevated sodium-lithium countertransport activity in erythrocytes in patients with NIDDM.

To understand the mechanism by which elevated sodium-lithium countertransport activity (SLC) associates with increased intracellular free calcium-ion concentration ([Ca2+]i), we investigated the relationship between SLC and the effects of the extracellular Ca2+ concentration ([Ca2+]o) and a Ca2(+)-channel blocker, nisoldipine, on [Ca2+]i in erythrocytes from 48 patients with non-insulin-dependent (Type 2) diabetes mellitus (NIDDM). There was a significant correlation between SLC and [Ca2+]i. Nisoldipine in the incubation medium significantly decreased [Ca2+]i, and there was a significant positive correlation between SLC and the degree of [Ca2+]i decrease. When the [Ca2+]o was elevated, [Ca2+]i was significantly increased, but nisoldipine almost completely suppressed this increase of [Ca2+]i. There was a significant positive correlation between SLC and the degree of the suppression. These data suggest that elevated SLC correlates with increased [Ca2+]i, and that the increased [Ca2i]i might be due to the increased Ca2+ influx through a dihydropyridine-sensitive Ca2+ pathway.

Adult↗

PubMed1997

Assessment of technetium-99m Technegas scintigraphy for ventilatory impairment in pulmonary emphysema: comparison of planar and SPECT images.

Pulmonary emphysema can be diagnosed easily by X-ray CT (CT) as a low attenuation area. Recently Tc-99m-Technegas (Technegas) has been used for ventilation scintigraphy. The present study was undertaken to assess the usefulness of planar and SPECT images by using Technegas scintigraphy in patients with pulmonary emphysema. Technegas scintigraphy, CT and pulmonary function tests were performed in 20 patients (males, age 32-78 years). We classified the findings of Technegas images into 4 grades. Comparing planar and SPECT images of Technegas, more detailed findings were shown by SPECT than by planar images in mild cases (6 cases, 30%). In more severe cases, findings of SPECT and planar images were equivalent (14 cases, 70%). The degree of abnormal findings obtained by SPECT was equivalent to that obtained by CT in severe cases (6 cases, 30%). SPECT should be excluded in advanced stages as indicated by planar images.

Adult↗

PubMed1997

Hepatocyte growth factor and digital clubbing.

The cause of digital clubbing is unknown. Hepatocyte growth factor (HGF) is a pleotrophic factor which has various biological effects. We measured serum HGF in 12 patients with digital clubbing; the underlying diseases of these patients were: lung cancer, 2; cystic fibrosis, 2; idiopathic pulmonary fibrosis, 3; lung cancer with idiopathic pulmonary fibrosis, 1; chronic hepatitis, 1; interstitial pneumonia with collagen disease, 2; and bronchiectasis, 1; nine hundred and fifty-seven normal volunteers and 17 lung cancer patients without clubbing served as the control. As a result, the serum HGF concentration in patients with digital clubbing (0.47 +/- 0.29 ng/ml) was significantly higher when compared to that of lung cancer patients without digital clubbing (0.15 +/- 0.04, p < 0.01). Therefore, we suggest that HGF may play a role in the formation of digital clubbing.

Bronchiectasis↗

PubMed1997

Anti-asthma effect of an antiviral drug, acyclovir: a clinical case and experimental study.

BACKGROUND: Although acyclovir (9-(2-hydroxyethoxymethyl) guanine) is an antiviral drug that inhibits DNA polymerase of herpes virus, we have had the experience of an asthmatic patient's peak flow rate being improved by oral administration of acyclovir. OBJECTIVE: The aim of this experiment is whether acyclovir has anti-asthma effects using an asthma model in guinea-pigs. METHODS: The airway response was induced by a single inhalation of calcium ionophore A23187 (2 mg/mL). The airway obstruction was estimated by the ratio of expiration to inspiration time (E/I). The peribronchial eosinophil infiltration and eosinophil influx into bronchoalveolar lavage (BAL) fluid 7 h after the inhalation were also examined. To assess the effects of acyclovir (1, 10, and 100 mg/kg), aminophylline (20 mg/kg) and pemirolast potassium (TBX, 20 mg/kg) on A23187-induced asthmatic response, the drugs were intraperitoneally administered before the inhalation. RESULTS: The immediate airway obstruction was significantly suppressed by acyclovir (10 mg/kg) and aminophylline, whereas different doses of acyclovir (1 and 100 mg/kg) and TBX showed only a small inhibitory effect on the airway obstruction. On the other hand, the peribronchial eosinophilia was most successfully inhibited by TBX. Acyclovir (10 mg/kg) and aminophylline also suppressed the eosinophilia significantly. Furthermore, acyclovir significantly suppressed eosinophil influx into BAL fluid, whereas aminophylline and TBX weakly suppressed the influx. CONCLUSION: These results suggest that acyclovir exhibits not only antiviral but also antiasthma activity.

Acyclovir↗

PubMed1997

Qualitative platelet 12-lipoxygenase abnormality in a patient with essential thrombocythemia.

Quantitative platelet 12-lipoxygenase (12-LOX) deficiency has been reported in some patients with myeloproliferative disorders (MPD). We report here for the first time a novel qualitative abnormality of the 12-LOX enzyme of platelets from a patient with essential thrombocythemia. The anti-12-LOX immunoprecipitates from the patient's platelet homogenates showed a deficiency of 12-LOX activity, but contained normal amount of 12-LOX protein. There was no difference in subcellular localization of the enzyme between the patient's platelets and normal ones. This 12-LOX protein lacking its enzyme activity showed slightly larger electrophoretic mobility than normal one, suggesting a molecular abnormality of the enzyme. However, we could not detect any genetic mutation causing such abnormalities in all exons of 12-LOX gene by sequencing the patient's PCR-amplified DNA. Thus, our results indicate that the deficient activity of this abnormal 12-LOX protein is probably due to a posttranslational modification, and the possibility that platelets of some MPD patients have qualitative abnormality of the 12-LOX enzyme besides quantitative ones.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1996

Anti-interleukin-6 receptor antibody prevents muscle atrophy in colon-26 adenocarcinoma-bearing mice with modulation of lysosomal and ATP-ubiquitin-dependent proteolytic pathways.

Progression of skeletal muscle atrophy is one of the characteristic features in cancer patients. Interleukin-6 (IL-6) has been reported to be responsible for the loss of lean body mass during cancer cachexia in colon-26 adenocarcinoma (C-26)-bearing mice. This study was carried out to elucidate the intracellular proteolytic pathways operating in skeletal muscle in C-26-bearing mice, and to examine the effect of anti IL-6 receptor antibody on muscle atrophy. On day 17 after tumor inoculation, the gastrocnemius muscle weight of C-26-bearing mice had significantly decreased to 69% of that of the pair-fed control mice. This weight loss occurred in association with increases in the mRNA levels of cathepsins B and L, poly-ubiquitin (Ub) and the subunits of proteasomes in the muscles. Furthermore, enzymatic activity of cathepsin B+L in the muscles also increased to 119% of the control. The administration of anti-murine IL-6 receptor antibody to C-26-bearing mice reduced the weight loss of the gastrocnemius muscles to 84% of that of the control mice, whose enzymatic activity of cathepsin B+L and mRNA levels of cathepsin L and poly-Ub were significantly suppressed compared with those of the C-26-bearing mice. Our data indicate that both the lysosomal cathepsin pathway and the ATP-dependent proteolytic pathway might be involved in the muscle atrophy of C-26-bearing mice. The results also suggest that anti IL-6 receptor antibody could be a potential therapeutic agent against muscle atrophy in cancer cachexia by inhibiting these proteolytic systems.

Adenocarcinoma↗

PubMed1996

Temperature-dependent enhancement of proteolysis in C2C12 myotubes in association with the activation of 26S proteasome.

The effect of temperature on protein metabolism of C2C12 myotubes was investigated in order to estimate the potential effect of fever on muscle catabolism. The half-life of long-lived proteins in C2C12 myotubes was significantly (13%) shorter when incubated at 40 degrees C than at 37 degrees. The activities of cathepsins B and L were not significantly different at 37 and 40 degrees C, nor were the levels of the protein and mRNA of the two cathepsins. In contrast, the chymotrypsin-like activity of 26S proteasome was elevated by 53% at 40 degrees C, compared to that at 37 degrees C, although it was not associated with an increase in the levels of the protein and mRNA of proteasome subunits. mRNA levels of calpain and ubiquitin were not affected by temperature. It is concluded that temperature-dependent enhancement of proteolysis in C2C12 myotubes is associated with an increase in 26S proteasome activity.

Animals↗

PubMed1996

Characterization of a small-cell-lung-carcinoma cell line from a patient with cancer-associated retinopathy.

We examined the biologic properties of a small-cell-lung-carcinoma (SCLC) cell line (designated MN-1112) established from a patient with SCLC who showed paraneoplastic retinopathy syndrome. Morphologic and immunocytochemical analyses showed that MN-1112 cells possess features of the classic type of SCLC. MN-1112 cells grew in suspension forming relatively large clumps of cells with a doubling time of 72 hr. By light-microscope examination, the cells were relatively small and had scanty cytoplasm. The cells produced NSE, ACTH and CK (BB isozyme); they also expressed recoverin, a novel photoreceptor protein, detected by Northern-blot and Western-immunoblot analysis using human-recoverin-specific DNA probe and anti-bovine-recoverin polyclonal antibody. This report shows that human recoverin is expressed in cultured SCLC cells. Our results support the hypothesis that, in cancer-associated retinopathy (CAR) patients, auto-immune antibody targeting for ectopic recoverin in SCLC is initially produced and cross-reacts with the retinal protein, resulting in the retinal degeneration that occurs in CAR patients.

Aged↗

PubMed1996

Dose escalation study of carboplatin with fixed-dose etoposide plus granulocyte-colony stimulating factor in patients with small cell lung carcinoma. A study of the Lung Cancer Study Group of West Japan.

BACKGROUND: We performed a Phase I-II trial to determine the maximum tolerated dose of carboplatin (CBDCA) with a fixed dose of VP-16 and granulocyte-colony stimulating factor (G-CSF) in small cell lung cancer (SCLC) patients. METHODS: Treatment consisted of a starting dose of CBDCA, 400 mg/m2 (i.v., Day 1); VP-16, 100 mg/m2 (i.v., Days 1-3), and G-CSF, 2 micrograms/kg (s.c., Days 4-17) every 4 weeks for four cycles. The dose of CBDCA was escalated in increments of 50 mg/m2 until Grade IV toxicity on the World Health Organization scale developed in two-thirds or more of the patients. RESULTS: Seventy-five previously untreated patients with pathology confirmed SCLC were entered into the trial. Seventy-one patients were eligible and 70 patients were evaluated for response. Forty-five patients had limited disease (LD) and 26 had extensive disease (ED). The response rate of the 70 patients who could be evaluated was 81%, with 23% attaining a complete response (CR) and 58% attaining a partial response (PR). The response rate was 80% in LD patients (CR, 23%; PR, 57%) and 85% in ED patients (CR, 23%; PR, 62%). The major dose-limiting toxicity was thrombocytopenia. Nephrotoxicity, neurotoxicity, and ototoxicity were uncommon. The doses of CBDCA that resulted in unacceptable thrombocytopenia were 700 mg/m2 in patients younger than 70 years and 500 mg/m2 in patients older than 70 years. Overall median survival time (MST) was 9 months. MST of LD patients and ED patients were 11 months and 7 months, respectively. The dose-limiting toxicity of CBDCA with a fixed dose of VP-16 and using G-CSF as bone marrow rescue was age-related thrombocytopenia. The maximum tolerated dose of CBDCA was 650 mg/m2 if patients were younger than 70 years and 450 mg/m2 if they were 70 years or older. CONCLUSIONS: When we retrospectively compared our results with those using standard chemotherapy regimens, we saw no therapeutic benefit from increasing planned doses of CBDCA up to 700 mg/m2 in combination with G-CSF in patients with SCLC.

Aged↗

PubMed1996

Interleukin 6 receptor antibody inhibits muscle atrophy and modulates proteolytic systems in interleukin 6 transgenic mice.

The muscles of IL-6 transgenic mice suffer from atrophy. Experiments were carried out on these transgenic mice to elucidate activation of proteolytic systems in the gastrocnemius muscles and blockage of this activation by treatment with the anti-mouse IL-6 receptor (mIL-6R) antibody. Muscle atrophy observed in 16-wk-old transgenic mice was completely blocked by treatment with the mIL-6R antibody. In association with muscle atrophy, enzymatic activities and mRNA levels of cathepsins (B and L) and mRNA levels of ubiquitins (poly- and mono-ubiquitins) increased, whereas the mRNA level of muscle-specific calpain (calpain 3) decreased. All these changes were completely eliminated by treatment with the mIL-6R antibody. This IL-6 receptor antibody could, therefore, be effective against muscle wasting in sepsis and cancer cachexia, where IL-6 plays an important role.

Animals↗

PubMed1996

Elevated erythrocyte sodium-lithium countertransport activity correlates with increased intracellular sodium and free calcium-ion concentration in type 2 diabetes.

To explore the mechanism by which elevated sodium-lithium countertransport activity (SLC) associates with both predisposition to hypertension and diabetic nephropathy, we investigated the interrelationships among SLC, intracellular sodium concentration ([Na]i), intracellular free calcium-ion concentration ([Ca2+]i), diabetic nephropathy, hypertension, family history of hypertension, and other factors in 48 patients with Type 2 diabetes and 24 healthy controls. There was a significant correlation between SLC and [Na]i (r = 0.36, p < 0.05), [Na]i and [Ca2+]i (r = 0.47, p < 0.01), SLC and [Ca2+]i (r = 0.46, p < 0.01), and between HbA1c and [Ca2+]i (r = 0.38, p < 0.01). Both [Na]i and [Ca2+]i were significantly higher in the patients with elevated SLC than in those with normal SLC (p < 0.01 and p < 0.05, respectively). In stepwise multivariate regresssion analysis, [Na]i, HbA1c, and SLC appeared as independent determinants of [Ca2+]i. These data suggest a significant correlation of elevated SLC with increased [Na]i and [Ca2+]i. This may be a possible mechanism underlying the close association of elevated SLC with both predisposition to hypertension and diabetic nephropathy.

Adult↗