A randomized phase III trial comparing S-1 versus UFT as adjuvant chemotherapy for stage II/III rectal cancer (JFMC35-C1: ACTS-RC)

This phase III study is the first study to demonstrate the superiority of new oral fluoropyrimidine S-1 over tegafur–uracil as adjuvant chemotherapy for stage II/III rectal cancer patients with no preoperative treatment in terms of relapse-free survival. S-1 can be considered an important option, especially for patients who have not received preoperative treatment.

Backgrounds

Preventing distant recurrence and achieving local control are important challenges in rectal cancer treatment, and use of adjuvant chemotherapy has been studied. However, no phase III study comparing adjuvant chemotherapy regimens for rectal cancer has demonstrated superiority of a specific regimen. We therefore conducted a phase III study to evaluate the superiority of S-1 to tegafur–uracil (UFT), a standard adjuvant chemotherapy regimen for curatively resected stage II/III rectal cancer in Japan, in the adjuvant setting for rectal cancer.

Patients and methods

The ACTS-RC trial was an open-label, randomized, phase III superiority trial conducted at 222 sites in Japan. Patients aged 20–80 with stage II/III rectal cancer undergoing curative surgery without preoperative therapy were randomly assigned to receive UFT (500–600 mg/day on days 1–5, followed by 2 days rest) or S-1 (80–120 mg/day on days 1–28, followed by 14 days rest) for 1 year. The primary end point was relapse-free survival (RFS), and the secondary end points were overall survival and adverse events.

Results

In total, 961 patients were enrolled from April 2006 to March 2009. The primary analysis was conducted in 480 assigned to receive UFT and 479 assigned to receive S-1. Five-year RFS was 61.7% [95% confidence interval (CI) 57.1% to 65.9%] for UFT and 66.4% (95% CI 61.9% to 70.5%) for S-1 [P = 0.0165, hazard ratio (HR): 0.77, 95% CI 0.63–0.96]. Five-year survival was 80.2% (95% CI 76.3% to 83.5%) for UFT and 82.0% (95% CI 78.3% to 85.2%) for S-1. The main grade 3 or higher adverse events were increased alanine aminotransferase and diarrhea (each 2.3%) in the UFT arm and anorexia, diarrhea (each 2.6%), and fatigue (2.1%) in the S-1 arm.

Conclusion

One-year S-1 treatment is superior to UFT with respect to RFS and has therefore become a standard adjuvant chemotherapy regimen for stage II/III rectal cancer following curative resection.

Therapeutic effect of a new immunosuppressive agent, everolimus, on interleukin-10 gene-deficient mice with colitis

A limited number of therapeutic strategies are currently available for patients with inflammatory bowel disease (IBD). In particular, the maintenance therapy after remission in Crohn's disease (CD) is not satisfactory and new approaches are needed. Interleukin-10 gene-deficient (IL-10-/-) mice, a well-characterized experimental model of CD, develop severe chronic colitis due to an aberrant Th1 immune response. Everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), a new immunosuppressive reagent, has been used successfully in animal models for heart, liver, lung and kidney transplantation. In the present study, we examined the efficacy of everolimus in the treatment of chronic colitis in an IL-10-/- mouse model. Everolimus was administered orally for a period of 4 weeks to IL-10-/- mice with clinical signs of colitis. The gross and histological appearances of the colon and the numbers, phenotype and cytokine production of lymphocytes were compared with these characteristics in a control group. The 4-week administration of everolimus resulted in a significant decrease in the severity of colitis, together with a significant reduction in the number of CD4+ T cells in the colonic lamina propria as well as IFN-gamma production in colonic lymphocytes. Everolimus treatment of established colitis in IL-10-/- mice ameliorated the colitis, probably as a result of decreasing the number of CD4+ T cells in the colonic mucosa and an associated reduction in IFN-gamma production.

Inhibition of donor-derived T cells trafficking into target organs by FTY720 during acute graft-versus-host disease in small bowel transplantation

In small bowel transplantation (SBTx), graft-versus-host disease (GVHD) is mediated by donor-derived T cells recognizing host major histocompatibility complex (MHC) alloantigens, and represents an important immunological event influencing life in experimental and clinical situations. We evaluated the possibility that a new sphingosine 1-phosphate receptor agonist, FTY720, could diminish GVHD in a rat SBTx model through traffic alteration of donor-derived T cells in target organs. Heterotopic SBTx was performed using a parent (WF)-into-F(1) (WF x ACI) rat combination. Recipient survival, body weight, histopathology, donor-derived T cell subpopulation and cytokine production were compared with untreated controls. FTY720 inhibited lethality and histopathological changes in target organs when administered at 0.5 mg/kg, possibly due to sequestration of donor-derived T cells in the intestinal graft. FTY720 caused a significant reduction in donor T cell numbers in target organs by promoting these cells to home into donor, but not recipient, secondary lymphoid tissues. FTY720 significantly decreased production of interferon (IFN)-gamma in target organs. These findings indicate that FTY720 effectively reduced recirculation of activated donor-derived T cells and recruitment to target organs in GVHD, and was also associated with down-regulated IFN-gamma production. These properties may offer the potential to treat ongoing GVHD in SBTx.

Regulation of Donor T Cells in the Tolerant Rats to Graft-Versus-Host Disease by FTY720 Following Small Bowel Transplantation

AIMS

The potency of immunosuppression is a critical factor in small bowel transplantation (SBTx). FTY720 altered lymphocyte trafficking and prevented the donor T cells from migrating into target organs, resulting in the prolongation of recipient survival in acute graft-versus-host disease (GVHD) of SBTx. However, the effect of FTY720 on donor T cells in the chronic phase of GVHD following SBTx remains unclear.

METHODS

Heterotopic SBTx was performed in a WF-to-F1 (WF x ACI) rat combination. Recipients were given FTY720 for 14 days after SBTx. The subpopulations of donor-derived T cells and the cytokine production in the target tissues were evaluated on postoperative day 150.

RESULTS

FTY720 treatment significantly prolonged recipient survival over 150 days without any clinical signs of GVHD. The numbers of donor-derived CD4+ and CD8+ T cells in the peripheral blood, mesenteric lymph nodes, and Peyer's patches of recipients were maintained at low levels on postoperative 150, which were almost similar to the levels on postoperative day 14. In the host lamina propria, however, a significant higher number of donor T cells (CD4+, 18.4 +/- 4.3 x 10(4); CD8+, 13.9 +/- 3.6 x 10(4)) were still observed on postoperative day 150. Production of interferon-gamma was significantly reduced in target tissues by FTY720 treatment both in the acute and chronic phase. However, interleukin-4 and interleukin-10 production, which was significantly higher on day 14, returned to the level of naive rats in the chronic phase.

CONCLUSIONS

A 14-day treatment of FTY720 induced tolerance in our SBTx model. Down-regulation of both Th1 and Th2 immune response was observed in the chronic phase.

[Posterior mediastinal paraganglioma with a 60-year history; report of a case]

We report a case of a 68-year-old man with a posterior mediastinal tumor. He remembered having difficulty in food passage through his esophagus in childhood. The preoperative thoracic computed tomography (CT) revealed a 5 x 3 cm mass with strong enhancement in the posterior mediastinum. A right thoracotomy was performed to resect this indeterminate mass. Complete resection was achieved. The pathologic diagnosis was paraganglioma. Postoperatively, he experienced more comfortable food passage through his esophagus than ever before. There has been no sign of recurrence 3 years after the operation. The tumor was clinically diagnosed as benign paraganglioma because of its long silent course.

Advantages of laparoscope-assisted surgery for recurrent Crohn's disease

BACKGROUND

Laparoscopic surgery has been applied to patients with primary Crohn's disease, and its beneficial outcomes have been already investigated. However, there is no systematic study of laparoscopic surgery for patients with recurrent diseases.

METHODS

We performed reoperation for 43 patients with recurrent Crohn's disease, including 23 patients who underwent laparoscope-assisted surgery.

RESULTS

For all the patients, laparoscope-assisted surgery could be performed safely, even if the patients had been treated previously by open surgery or had undergone multiple abdominal procedures. Conversion to open or hand-assisted laparoscopic surgery was necessary for 16 patients (69.6%) because of dense adhesions (11 cases) or bulky tumor (5 cases). Importantly, even if the procedure was converted, the skin incision was significantly shorter than with open surgery, and postoperative recovery was faster, especially for the patients who underwent conversion to hand-assisted laparoscopic surgery.

CONCLUSIONS

Laparoscope-assisted surgery is feasible and advantageous in reoperation for patients with recurrent Crohn's disease.

The sarcolemmal proteins dysferlin and caveolin-3 interact in skeletal muscle

Dysferlin is a surface membrane protein in skeletal muscle whose deficiency causes distal and proximal, recessively inherited, forms of muscular dystrophy designated Miyoshi myopathy (MM) and limb girdle muscular dystrophy type 2B (LGMD2B), respectively. The function of dysferlin is not defined. Caveolin-3 is another skeletal muscle membrane protein which is important in the formation of caveolae and whose mutations cause dominantly inherited limb girdle muscular dystrophy type 1C (LGMD1C). We report that dysferlin co-immunoprecipitates with caveolin-3 from biopsied normal human skeletal muscles. We also describe abnormal localization of dysferlin in muscles from patients with LGMD1C including novel missense mutation (T64P) in the human caveolin-3 gene (CAV3). The immunoprecipitation data are consistent with the parallel observation that dysferlin immunostaining is not normal in LGMD1C muscles. Amino acid sequence analysis of the dysferlin protein reveals seven sites that correspond to caveolin-3 scaffold-binding motifs, and one site that is a potential target to bind the WW domain of the caveolin-3 protein. This is the first description of a possible dysferlin interacting protein; it suggests the hypothesis that one function of dysferlin may be to interact with caveolin-3 to subserve signaling functions of caveolae.

Antigen-presenting hybridoma cells expressing MHC antigens of the LEW rat

Towards the eventual purpose of facilitating analyses of specificities and functions of LEW rat T lymphocytes involved in the induction and development of organ-specific autoimmune disorders, hybridoma cells expressing class I and class II MHC antigens of LEW rat have been developed. B cell hybridomas produced between a murine B cell tumor M12.4.5 and stimulated LEW B cells expressed high levels of LEW class II MHC antigen but the expression of LEW class I MHC antigens on these cells was rather low. The B hybridoma cells were capable of presenting soluble protein antigens to LEW CD4(+) T cells. Furthermore, The use of this hybridoma revealed antigen-specific cytolytic activity of rat CD4(+) T cells. T cell hybridomas produced between murine thymoma BW5147 and LEW T cells expressed class I MHC antigens of the LEW rat. The expression was confirmed by surface staining and specific cytolysis by rat allogeneic CTL.

Distal anterior compartment myopathy: a dysferlin mutation causing a new muscular dystrophy phenotype

We report a family with a new phenotype of autosomal recessive muscle dystrophy caused by a dysferlin mutation. The onset of the illness is distal, in the muscles of the anterior compartment group. The disease is rapidly progressive, leading to severe proximal weakness. Muscle biopsy showed moderate dystrophic changes with no vacuoles. Dysferlin immunostaining was negative. Gene analysis revealed a frameshift mutation in the exon 50 (delG5966) of the DYSF gene. This phenotype further demonstrates the clinical heterogeneity of the dysferlinopathies.

Identification of the sex chromosomes of the medaka, Oryzias latipes, by fluorescence in situ hybridization

In the medaka, Oryzias latipes, which does not have cytologically recognizable sex chromosomes, the sex is genetically determined and the mechanism of sex determination (XX/XY) can be revealed by genetic crosses using a particular pigment gene. In a previous study, we isolated a sex-linked DNA marker (SL1) using the genomic differences between inbred strains of medaka. In the present paper, we further isolated another sex-linked clone (pHO5.110). The pHO5. 110-related sequences were tightly linked to sex in O. latipes. We designated the locus of the pHO5.110-related sequence on sex chromosomes of medaka as Sex-Linked 2 (SL2). Southern blot analyses suggested that the pHO5.110-related sequence was tandemly repetitive in the medaka genome. Using the clone as a probe for FISH analysis, strong hybridization signals were obtained in a couple of chromosomes that formed one of two large submetacentric chromosome pairs. The pHO5.110-related sequences were repetitive in the genomes of other species of Oryzias (O. curvinotus, O. luzonensis and O. mekongensis) that are karyologically related to O. latipes (all are members of the so-called biarmed group). By contrast, the sequences were not detected as repetitive in other Oryzias species. Hence, it is thought that pHO5.110-related sequences were amplified in the genome of a common ancestor of the biarmed group.

Experimental autoimmune myocarditis and its pathomechanism

The pathomechanisms of autoimmune myocarditis are quite different from viral infection. In this type of myocarditis, cardiac myosin fragments, proper dendritic cells and autoreactive T cells are the 3 major elements in initiating and promoting the inflammation. The causative epitope is locating on the S2 rod portion of the myosin heavy chain (MHC). Through our recombinant study, the peptide was found to be located on the latter half of MHC residues 1070 to 1165. Activity of antigenicity was not different between alpha and beta chain. The cardiac dendritic cell presents a unique structure with large mononuclear and interdigitating processes. This antigen presenter is quickly activated and suppressed by the antigen. The autoreactive T cell is closely linked with cytokine production. In the initial stage of myocarditis, IL-2 and IL-12 are increased. According to the progression of inflammatory changes, a great amount of IL-1b, INF-gamma and TNF-alpha is released around the diseased tissue. At the same time, NO is massively produced from infiltrating macrophages. Cytokines secreted from inflammatory cells accelerate T cell induction from Th0 to Th1. In the convalescent stage, production of TGF-beta 1 and IL-10 become dominant. They contribute to cell induction from Th0 to Th2.

Dysferlin is a surface membrane-associated protein that is absent in Miyoshi myopathy

Recently we reported that mutations in a muscle protein "dysferlin" are present in limb girdle muscular dystrophy-2B and a related, adult-onset, distal dystrophy known as Miyoshi myopathy (MM). We report that antibodies to dysferlin identify a protein of approximately 230 kDa and show that dysferlin is located in the muscle membrane. This protein is absent in MM and LGMD-2B muscle. By contrast, dystrophin and other dystrophin-associated proteins are normal in these patients. Thus, dysferlin is a membrane-associated protein that is not likely to be an integral component of the dystrophin complex. Although it is not essential for initial myogenesis, it appears to be critical for sustained normal function in mature muscle.

Salivary gland aplasia with cleft lip and palate: a case report and review of the literature

We report the case of a patient with lifelong symptoms of xerostomia and a repaired bilateral cleft lip and palate. The clinical evaluation demonstrated aplasia of the major salivary glands. A review of the literature pertaining to salivary gland aplasia is presented, along with a summary of the data regarding patient gender, defect sites, hereditary background, and combined manifestations. The diagnostic methods, possible pathogenesis, and management are also discussed.

Mutations in the integrin alpha7 gene cause congenital myopathy

The basal lamina of muscle fibers plays a crucial role in the development and function of skeletal muscle. An important laminin receptor in muscle is integrin alpha7beta1D. Integrin beta1 is expressed throughout the body, while integrin alpha7 is more muscle-specific. To address the role of integrin alpha7 in human muscle disease, we determined alpha7 protein expression in muscle biopsies from 117 patients with unclassified congenital myopathy and congenital muscular dystrophy by immunocytochemistry. We found three unrelated patients with integrin alpha7 deficiency and normal laminin alpha2 chain expression. To determine if any of these three patients had mutations of the integrin alpha7 gene, ITGA7, we cloned and sequenced the full-length human ITGA7 cDNA, and screened the patients for mutations. One patient had splice mutations on both alleles; one causing a 21-bp insertion in the conserved cysteine-rich region, and the other causing a 98-bp deletion. A second patient was a compound heterozygote for the same 98-bp deletion, and had a 1-bp frame-shift deletion on the other allele. A third showed marked deficiency of ITGA7 mRNA. Clinically, these patients showed congenital myopathy with delayed motor milestones. Our results demonstrate that mutations in ITGA7 are involved in a form of congenital myopathy.

MyoD is indispensable for muscle-specific alternative splicing in mouse mitochondrial ATP synthase gamma-subunit pre-mRNA

Muscle-specific alternative RNA splicing is an essential step during myogenesis. In this paper, we report that a muscle-specific transcription factor, MyoD, plays a central role in the induction of muscle-specific alternative splicing during myogenesis. Recently, we reported that muscle and nonmuscle isoforms of the mitochondrial ATP synthase gamma-subunit (F1gamma) were generated by alternative splicing and that acidic stimulation promoted this muscle-specific alternative splicing (Endo, H., Matsuda, C., and Kagawa, Y. (1994) J. Biol. Chem. 269, 12488-12493). In this report, mouse myoblasts are shown to express the muscle-specific isoform of F1gamma after induction with low-serum medium (differentiation medium) or acidic medium, although myotube formation was not detected after acidic induction. RNA blot analysis revealed that the expression levels of both MEF2 and myogenin were increased by low-serum induction, but not by acidic induction. High expression of MyoD mRNA was observed after both types of induction. Overexpression of exogenous MyoD in fibroblasts showed that MyoD was necessary for muscle-specific alternative splicing in both types of induction. Exogenous Id, a negative regulator of MyoD, blocked muscle-specific alternative splicing of F1gamma pre-mRNA by both types of induction. In addition, MyoD induced several muscle-specific alternative splicings, including structural protein pre-mRNAs such as beta-tropomyosin and neural-cell adhesion molecule and transcriptional protein pre-mRNAs such as MEF2A and MEF2D. Our analysis of the two induction systems shows a common MyoD-dependent mechanism of muscle-specific alternative splicing in several genes, independent of MEF2 and myogenin.

A field trial of oil adjuvanten trivalent Actinobacillus pleuropneumoniae vaccine

The trivalent vaccine of A. pleuropneumoniae serotype 1, 2 and 5 (AP3V) was prepared in the oil-in-water type adjuvanten form. At an SPF farm, the vaccinated pigs were observed for their antibody response, finishing rate, and lung lesions at the time of slaughter and for injection scars. The CF titers against serotype 1, 2 and 5 started to rise after the second injection, showed the highest titer at 30 days after injection and then gradually decreased in vaccinated pigs. The finishing rate in the vaccinated group was 91.6% and that in the control group immunized with commercial vaccine was 60%. The lungs in the control pigs showed severe pneumonia with hyperemia, pleural adhesion and abscess. In contrast, vaccinated pigs showed slight pneumonia. Injection scars were not observed in vaccinated pigs 100 days after the second injection. In conclusion, the pigs immunized with AP3V were sufficiently protected against A. pleuropneumoniae infection and the trial proved to be satisfactory in the safety of the vaccine under field conditions.

Biosynthesis of phytosiderophores, mugineic acids, associated with methionine cycling

The biosynthesis of 2'-deoxymugineic acid, a key phytosiderophore, was examined in association with the putative methionine recycling pathway in the roots of wheat using labeling experiments and structural analysis. Feeding with D-[1-13C]ribose did not result in 13C enrichment of 2'-deoxymugineic acid, while D-[2-13C]ribose resulted in 13C enrichment at the C-4", -1, -4' positions, and D-[5-13C]ribose did in C-1', -4, and -1" positions of 2'-deoxymugineic acid, respectively. Furthermore, two isotope-labeled intermediates of the methionine recycling pathway, 5-[5-2H2]methylthioribose and 2-[1-13C]keto-4-methylthiobutyric acid, were synthesized, and their incorporation into 2'-deoxymugineic acids was investigated. Six deuterium atoms at the C-4, -1', and -1" positions of 2'-deoxymugineic acid were observed after feeding with 5-[5-2H2]methylthioribose. Feeding with 2-[1-13C]keto-4-methylthiobutyric acid yielded 2'-deoxymugineic acid enriched with 13C at the C-4', -1, and -4" positions. These results demonstrated for the first time that the biosynthesis of 2'-deoxymugineic acid is associated with the methionine recycling pathway. This association system functions to recycle methionine required for continued synthesis of mugineic acids in the roots of gramineous plants.

DNA rearrangements in Japanese facioscapulohumeral muscular dystrophy patients: clinical correlations

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular disorder in which the disease locus has been mapped to chromosome 4q35-qter. In most patients, the DNA rearrangements associated with FSHD have been found in the EcoRI fragment detected by the p13E-11 probe, and deletions of the 3.2 kb repeat units within the fragment are thought to cause the disease. To examine FSHD-associated DNA rearrangements in the Japanese population, we performed Southern blot analysis of the genomic DNA, using the p13E-11 and pFR-1 probes, in 158 Japanese individuals, including 38 FSHD patients from 19 families. We found that all but one (a possible affected recombinant) of the Japanese FSHD patients (97.4%) had specific smaller (< 28 kb) EcoRI fragments which cosegregated with the disease; this included four patients who had severe inflammatory changes in the muscle and eight patients with de novo DNA rearrangements. We found no FSHD patient who had a fragment larger than 28 kb. By contrast, only two of 35 Japanese controls (5.7%) had EcoRI fragments smaller than 28 kb. Our patients showed anticipation, i.e. decreased size of the EcoRI fragment in parallel with earlier onset of the disease (r = 0.531, P = 0.003, with younger age at onset in children (17.8 +/- 7.0) than their affected parents (31.5 +/- 14.8) (P = 0.019). However, since each family had a specific small EcoRI fragment associated with the disease, the differing clinical severity within a family cannot be explained by the size of the fragment alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning and mapping of a very short (10-kb) EcoRI fragment associated with facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly inherited muscular disorder and the gene for FSHD has been mapped to chromosome 4q35. Recently, the DNA rearrangements associated with the disease were found in the EcoRI fragment detected by the probes p13E-11 and pFR-1, and deletions of the 3.3-kb KpnI repeat units within the EcoRI fragment are thought to cause the disease. In this study, we cloned the FSHD-associated EcoRI fragments (the shortest fragments identified to date: 10 kb) from 2 severely affected patients (unrelated). Restriction enzyme maps of the genomic fragments in the 2 patients revealed that the 10 kb fragments were identical and contained only one 3.3-kb KpnI repeat unit. These results suggest that deletions of the 3.3-kb KpnI repeat units are likely to associate with FSHD, and that the 10 kb fragments may provide a means of understanding the molecular details involved at the site of the chromosomal rearrangements in FSHD.

Cloning and mapping of a very short (10-kb) EcoRI fragment associated with facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly inherited muscular disorder and the gene for FSHD has been mapped to chromosome 4q35. Recently, the DNA rearrangements associated with the disease were found in the EcoRI fragment detected by the probes p13E-11 and pFR-1, and deletions of the 3.3-kb Kpnl repeat units within the EcoRI fragment are thought to cause the disease. In this study, we cloned the FSHD-associated EcoRI fragments (the shortest fragments identified to date: 10 kb) from 2 severely affected patients (unrelated). Restriction enzyme maps of the genomic fragments in the 2 patients revealed that the 10 kb fragments were identical and contained only one 3.3-kb Kpnl repeat unit. These results suggest that deletions of the 3.3-kb Kpnl repeat units are likely to associate with FSHD, and that the 10 kb fragments may provide a means of understanding the molecular details involved at the site of the chromosomal rearrangements in FSHD.

Characterization of a tandemly repeated 3.3-kb Kpnl unit in the facioscapulohumeral muscular dystrophy (FSHD) gene region on chromosome 4q35

A 3.3-kb Kpnl repeat unit within the tandem repeat locus (D4Z4) and its upstream 2.5-kb Hincll/Kpnl fragment of the facioscapulohumeral muscular dystrophy (FSHD) gene region at 4q35-qter were sequenced and characterized. The 3.3-kb Kpnl unit was 3303 bp in length and contained two homeodomain sequences, one LSau-like sequence, and several microsatellites. The GC content in the 3.3-kb unit was very high (73%), while it was only 35% in the nonrepeated region of the 2.5-kb fragment. We identified 99% homologous sequences (918 bp) in the 3' end of the 3.3- and 2.5-kb fragments. These findings suggested that the repeated sequences at the D4Z4 start from 918 bp upstream to the first Kpnl site.

Exclusion of an alternatively spliced exon in human ATP synthase gamma-subunit pre-mRNA requires de novo protein synthesis

Tissue-specific isoforms of the mitochondrial ATP synthase gamma-subunit are generated by alternative splicing, and the heart/skeletal muscle-specific transcript lacks exon 9 in a cassette fashion (Matsuda, C., Endo, H., Hirata, H., Morosawa, H., Nakanishi, M., and Kagawa, Y. (1993) FEBS Lett. 325, 281-284; and Matsuda, C., Endo, H., Ohta, S., and Kagawa, Y. (1993) J. Biol. Chem. 268, 24950-24958). Here, we show that the endogenous heart-type mRNA is cell-specifically induced by the extracellular pH value in the HT1080 (human fibrosarcoma) and KYM-1 (human rhabdomyosarcoma) cell lines. In these cells, a low extracellular pH value induced exclusion of exon 9, and this induction was inhibited by cycloheximide treatment. In contrast, a high extracellular pH value resulted in mRNA transcription of the liver type, including exon 9, and did not require de novo protein synthesis. These results suggest that alternative splicing in the gamma-subunit pre-mRNA is regulated by on-off switching of protein synthesis of a trans-acting factor involved in this exon-excluding step. The signal of low pH value was blocked by the protein kinase inhibitor H-7 or Calphostin C (protein kinase C inhibitor), indicating the involvement of protein kinase C in the alternative splicing. This is a good model system for studies on the induction mechanism of alternative splicing in cultured mammalian cells, in which intracellular factors play a pivotal role for the exon-excluding step in the tissue-specific alternative splicing mechanism.

Comparison of the ATPase activities of bovine heart and liver mitochondrial ATP synthases with different tissue-specific gamma subunit isoforms

The kinetics of heart and liver mitochondrial ATPase (FoF1) were examined using submitochondrial particles (SMPs) purified from the two tissues to obtain information on the role of gamma subunit isoforms. The F1 portion is mainly composed of the catalytic, common alpha beta subunits and tissue-specific gamma subunits. In contrast to the previous reports on the kinetics and crystallography of various F1's, the Vmax and Km of the two isoforms of FoF1 were identical although the SMPs were prepared from different tissues. Moreover sodium azide inhibited the two equally. The ATPase activity of liver SMP showed slightly steeper pH-dependency than that of heart SMP but the pH optima of the two were the same (pH 8).

Gene structure of human mitochondrial ATP synthase gamma-subunit. Tissue specificity produced by alternative RNA splicing

We completely sequenced the human gene for ATP synthase gamma-subunit, which was approximately 23 kilobases long and was composed of 10 exons. Exons 1 and 2 encoded the N-terminal presequence required for mitochondrial import, while exons 9 and 10 encoded the C-terminal portions of mature protein. Enzymatic amplification of human heart and liver cDNAs using the polymerase chain reaction revealed two mRNA transcripts that were predicted to encode two 30-kDa isoforms of the gamma-subunit, which differed by the addition of a single amino acid (Asp273) at the C terminus of the liver type isoform. These two mRNA transcripts of the heart (H) type and liver (L) type were generated by alternative splicing of an exon. The same alternative splicing event was observed in bovine tissue. In human tissues, the H type mRNA devoid of exon 9 was expressed specifically in the heart and skeletal muscle, which require rapid energy supply. The L type mRNA was expressed in the brain, liver, kidney etc. Both transcripts were expressed in the skin, intestine, stomach, and aorta. This tissue specificity of transcript heterogeneity suggests the distinct functional or regulatory roles of the gamma-subunit isoforms in the catalysis of ATP synthase. This is the first report on tissue-specific isoforms generated by alternative splicing in an energy transducing mitochondrial protein.

Tissue-specific isoforms of the bovine mitochondrial ATP synthase gamma-subunit

Tissue-specific isoforms of the gamma-subunit of the bovine FoF1-ATP synthase were identified for the first time. The two isoforms, heart and liver type, were generated by alternative splicing, the liver-type RNA transcript containing a 37-nucleotide sequence as a cassette exon. Protein sequencing of the C-terminal fragments of the two isoforms of the F1 gamma-subunit indicated that the liver-type isoform had an additional aspartate residue at the C terminus, not present in the heart type one.

Multi-institutional studies on hyperthermia using an 8-MHz radiofrequency capacitive heating device (Thermotron RF-8) in combination with radiation for cancer therapy

A joint clinical trial of hyperthermia using a newly developed 8-MHz radiofrequency (RF) capacitive heating device (Thermotron RF-8; developed in cooperation with Yamamoto Vinyter Co. of Osaka) was performed under collaboration of seven institutions. Radiation with 4 Gy twice a week for a total of 40 Gy or 2 Gy five times a week for a total of 50 Gy was delivered. After irradiation, hyperthermia at 42.5 degrees C +/- 0.5 degree C for 40 to 60 minutes was given twice a week for a total of 10 times. Tumors examined in this trial were located in various depths in the body, and included those which were considered refractory to conventional treatments or radioresistant such as malignant melanoma and soft tissue tumors. Of the 63 tumors treated, 52.4% showed complete regression (CR); 19.0% more than 80% regression (PRa); 20.6%, 80% to 50% regression (PRb); and 8.0% no regression (NR). Our joint clinical trial demonstrated that hyperthermia with the use of the Thermotron RF-8 is safe and effective in the treatment of radioresistant tumors located in superficial, subsurface, and in some cases deep regions, if the surface cooling is properly managed by the temperature-controlled saline pad and electrodes of appropriate size are paired.