Structure and Function of Myosin Isoforms in Adult Chicken Hindlimb Muscles

Although large accumulation of sequence data is published for a variety of myosin heavy chain (MHC) isoforms, the meaning of heterogeneity among the amino acid sequences remains unclear as to the key contractile and biochemical properties of muscle fibres. In the present study, we studied on MHC isoforms in three adult chicken hindlimb muscles: ilio-tibialis, gastrocnemius and femoritibialis) and pectoralis muscle, by means of in vitro motility assay and measurement of ATPase activity. The motility speed of myosins and ATPase activities of myofibrils extracted from the hindlimb muscles were significantly lower than those from the pectoralis muscle consisting of a homogeneous MHC (P-type). ATPase activity of femori-tibialis myofibril was remarkably lower than those of ilio-tibialis and gastrocnemius myofibrils. We found the differential expression of MHC isoforms in these muscles by northern blot analysis. Furthermore, we determined the amino acid sequences of the 23kDa, 50kDa and 20kDa fragments from a major MHC isoform (G-type) found in the three hindlimb muscles. There was approximately 4.3% amino acid difference between G-type and P-type, however the characteristically methylated amino acids were recognized in the G-type at the same residues as in the P-type. In the course of sequencing the 20kDa fragment from femori-tibialis muscle myosin, we found another MHC isoform (F-type). Contentratios of P-type, G-type and F-type were about 3 : 7 : 0 in ilio-tibialis, 2 : 7 : 0 in gastrocnemius, and 1 : 6 : 3 in femori-tibialis, respectively. All these data suggest that the motility speed of myosin and ATPase activity of myofibril correlate with the content-ratio of the MHC isoforms in each muscle

Neoadjuvant chemotherapy with docetaxel, nedaplatin, and fluorouracil for resectable esophageal cancer : A phase II study

Cisplatin plus 5‐fluorouracil is regarded as standard neoadjuvant chemotherapy for esophageal squamous cell carcinoma (ESCC) in Japan, but the prognosis remains poor. We have previously described how definitive chemoradiotherapy with docetaxel, nedaplatin, and 5‐fluorouracil (DNF) led to a very high response rate and promising survival times. We therefore undertook a phase II trial to evaluate the feasibility and efficacy of neoadjuvant DNF. The study included patients with clinical stage Ib‐III ESCC. Chemotherapy consisted of i.v. docetaxel (30 mg/m2) and nedaplatin (50 mg/m2) on days 1 and 8, and a continuous infusion of 5‐fluorouracil (400 mg/m2/day) on days 1‐5 and 8‐12, every 3 weeks. After three courses of chemotherapy, esophagectomy was carried out. The primary end‐point was the completion rate of the protocol treatment. Twenty‐eight patients were enrolled (cStage Ib/II/III, 2/3/23) and all received at least two cycles of chemotherapy. Twenty‐five patients underwent surgery, all of whom achieved an R0 resection, leading to a completion rate of 89.3%. The overall response rate was 87.0%. A pathological complete response was confirmed in eight (32.0%) cases. Grade 3/4 adverse events included leukopenia (32.1%), neutropenia (39.3%), febrile neutropenia (10.7%), thrombocytopenia (10.7%), and diarrhea (14.3%), but were manageable. Treatment‐related deaths and major surgical complications did not occur. Estimated 2‐year progression‐free and overall survival rates were 70.4% and 77.2%, respectively. Thus, DNF therapy was well tolerated and deemed feasible, with a strong tumor response in a neoadjuvant setting for ESCC. This trial is registered with the University Hospital Medical Information Network (UMIN ID: 000014305)

Surgical benefits of liver hanging maneuver for hepatectomy of huge liver tumor

In hepatic surgery, it is very important to control bleeding during liver resection. However, in hepatectomy for a huge liver tumor it is often difficult to reduce bleeding volume and maintain an excellent surgical view. The anterior pproach, which is hepatectomy done using the liver hanging maneuver, has beneficial effects reducing bleeding volume and preventing scattering of cancer cells from huge liver tumors. W e investigated the surgical benefits of the liver anging maneuver during hepatectomy for huge liver tumors in our department.

Measuring the efficiency of collective floodplain aquaculture of Bangladesh using Data Envelopment Analysis

This study measures efficiency of collective floodplain aquaculture enterprises (FPAs) practiced in floodplains composed of private lands in Bangladesh using data envelopment analysis (DEA). We concentrate on a management system that was initially developed by landowners in the Daudkandi sub-district in 1984. With gradual spread of this management system two important internal variations have emerged in terms of (1) organizational composition that resulted from the investment-based participation of an NGO, and (2) mode of managing aquaculture operation that resulted from leasing out the aquaculture operation instead managing it by themselves in some FPAs. Taking consideration of these two variations, and using four inputs and one output, we measure the technical, scale, mix and overall efficiency of 15 FPAs selected from five districts. While 11 FPAs are technically efficient, only six are overall efficient. On average, NGO-collaborated FPAs (NFPAs) are more efficient (78.27%) than landowners-managed independent FPAs (IFPAs) (75.96%). However, IFPAs are only found in the Daudkandi region, where there are more efficient IFPAs than NFPAs. On the other hand, while lease-based operations show better average efficiency (79.56%), self-managed operations have more efficient units. We also find that the intensive use of inputs in most older FPAs does not make them more efficient, despite their higher fish yield, than relatively newer FPAs. Given the poverty, food security and nutrition linkage of floodplain aquaculture and continuous attempts to increase fish yield, the FPAs along with development partners and government agencies, should take account of efficiency-related aspects in policies and practice

Alkali Light Chain Isoforms of Skeletal Muscle Myosin Subfragment-1 and Actin Bundle Formation

Myosin subfragment-1 (S-1) has been shown to induce single actin filaments into bundles (Ando & Scales (1985) J. Biol. Chem. 260, 2321-2327 ; Ando (1987) J. Mol. Biol. 195, 351-358). We examined the influence of the alkali light chains of myosin on the actin bundling. Only S-1 isoenzyme possessing alkali 1 light chain (S-1 (Al)) was found to promote single actin filaments into bundles in presence of 10 to 80 mM NaCI. The other isoenzyme, S-1 (A2), possessing alkali 2 light chain, could not promote it under the same conditions. With alkali light chains exchange experiment, the functional difference was revealed to be responsible for a particular alkali light chain. Electron microscopic observation showed that the distance between adjacent actin filaments in the bundles was about 180A and actin bundles possessed transverse stripes at about 350 to 360A intervals in the long axis of a bundle. The bundle formation was predominant in excess of S-1 to actin, and was disassembled by ADP. addition. All these remarks of actin bundles were consistent with hyper-opalescence type actin bundles reported by Ando ((1987) J. Mol. Biol. 195, 351-358). Cross-linking studies of acto-S-1 indicated that actin bundles seemed to be assembled by binding of adjacent S-1 decorating actin filaments each other. The role of alkali light chains on actin bundle formation is discussed