Post-mortem changes of connectin in chicken skeletal muscle

To investigate the influence of connectin (titin) on meat tenderization during conditioning, changes in the content and the electrophoretic pattern of the connectin in chicken myofibrils isolated by gel permeation chromatography were studied. Significant difference of the content and the electrophoretic pattern of the connectin isolated was not observed between the preparations from fresh and stored muscle. Therefore, the connectin is unlikely to be responsible for the meat tenderization caused by conditioning.     

Characterization of the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase gene from Bacillus cereus YUF-4

A 1.4-kbp DNA fragment, including the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase (AACRII/BDH) gene from the chromosomal DNA of Bacillus cereus YUF-4, was cloned in Escherichia coli DH5alpha after its insertion into pUC119, and the resulting plasmid was named pAACRII119. The AACRII/BDH gene had an open reading frame consisting of 1047 bp encoding 349 amino acids. The enzyme exhibited not only AACR activity, but also BDH activity. However, the gene was not located in a 2,3-butanediol (BD) operon, as is the case in the BDH gene of Klebsiella pneumoniae and that of K. terrigena. In addition, there was no BD-cycle-related enzyme gene in the region surrounding the AACRII/BDH gene. The AACR and BDH activities in E. coli DH5alpha/pAACRII119 were 200-fold higher than those in the original B. cereus YUF-4. The characteristics of the AACRII/BDH from E. coli DH 5alpha/pAACRII119 are similar to those of the AACRII/BDH from B. cereus YUF-4. The AACRII/BDH was considered to belong to the NAD(P)- and zinc-dependent long-chain alcohol dehydrogenase (group I ADH) family on the basis of the following distinctive characteristics: it possessed 14 strictly conserved residues of microbial group I ADH and consisted of about 350 amino acids. The enzymatic and genetic characteristics of AACRII/BDH were completely different from those of BDHs belonging to the short-chain dehydrogenase/reductase family. These findings indicated that the AACRII/BDH could be considered a new type of BDH.     

Polarization-Maintaining Optical Fibers Used for a Laser Diode Redundancy System in a Submarine Optical Repeater

Polarization-maintaining optical fibers are developed for installation in a submarine optical repeater. These fibers preserve the polarization of light emitted from laser diodes (LD's) to a single-mode fiber through a light-switching coupler. Crosstalk of less than -30 dB in a l-m length of these optical fibers, called PANDA optical fibers, is achieved with a bending radius greater than 10 mm, twists of less than 60 turns, and tension of less than 3 kg, and ambient temperatures of -20-80°C. The mechanical strength of these fibers is the same as that of single-mode fibers.     

In vivo observation of subendocardial microvessels of the beating porcine heart using a needle-probe videomicroscope with a CCD camera

We developed a portable needle-probe videomicroscope with a charge-coupled device (CCD) camera to visualize the subendocardial microcirculation. In 12 open-chest anesthetized pigs, the sheathed needle probe with a doughnut-shaped balloon and a microtube for flushing away the intervening blood was introduced into the left ventricle through an incision in the left atrial appendage via the mitral valve. Images of the subendocardial microcirculation of the beating heart magnified by 200 or 400 on a 15-in. monitor were obtained. The phasic diameter change in subendocardial arterioles during cardiac cycle was from 114 +/- 46 microns (mean +/- SD) in end diastole to 84 +/- 26 microns in end systole (p < 0.001, n = 13, ratio of change = 24%) and that in venules from 134 +/- 60 microns to 109 +/- 45 microns (p < 0.001, n = 15, ratio of change = 17%). In contrast, the diameter of subepicardial arterioles was almost unchanged (2% decrease, n = 5, p < 0.01), and the venular diameter increased by 19% (n = 8, p < 0.001) from end diastole to end systole. Partial kinking and/or pinching of vessels was observed in some segments of subendocardial arterioles and venules. The percentage of systolic decrease in the diameter from diastole in the larger (> 100 microns) subendocardial arterioles and venules was greater than smaller (50-100 microns) vessels (both p < 0.05). In conclusion, using a newly developed microscope system, we were able to observe the subendocardial vessels in diastole and systole.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vibration control of flexible arm by multiple observer structure

This paper describes vibration control of a flexible arm by multiple‐observer structure using the accelerations of the arm. In general, a flexible arm has several oscillation modes. In the model of a flexible arm described as a two‐mass resonant system, the reaction torque feedback makes the flexible arm system stable. In the N‐mass resonant system, it is known that the reaction torque feedback makes all oscillation modes, only the reaction torque feedback is not enough to make the system stable. Resonance ratio control with the arm disturbance observer has been proposed. The arm disturbance observer is able to suppress the disturbance applied to the tip, but it is not sufficient for the disturbance applied to other points on the arm. The aim is to make the control system robust to arm inertia variation and disturbance. This paper proposes vibration control of flexible arm by acceleration feedback, and disturbance rejection by multiple‐observer structure using the acceleration of the arm. The validity of the proposed method is shown by simulations and experiments. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 68–75, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20175     

High alkaline phosphatase activity in 3p-induced human renal cancer cells

Some immortal human cell lines lack telomerase activity. These cell lines were found to contain small dispersed DNA hybridizing to TTAGGG repeats. Such DNA was located in their cytoplasm and nuclei. Normal human fibroblasts or telomerase-positive cell lines did not contain such DNA. Upon cloning and sequencing, it was shown to consist of TTAGGG repeats. When electrophoresed on neutral and alkaline agarose gels, it behaved as double-stranded and linear DNA. These results suggest that telomeric DNA is released from chromosomes in association with maintenance of telomeres in telomerase-negative cell lines.     

Mechanochemical solid-state polymerization. IX. Theoretical analysis of rate of drug release from powdered polymeric prodrugs in a heterogeneous system

We theoretically derived the rate equation of drug release from a simple model in a heterogeneous system. Four assumptions were used to simplify the model. Two kinds of rate equations for drug release derived from two possible limiting cases, that the rate-determining step is a diffusion or hydrolysis controlled process, can predict the experimental results up to 50% hydrolysis. However, the predictions at the later stage by these equations are insufficient. These results suggest that the process of drug release from powdered polymeric prodrugs in a heterogeneous system must be described by both diffusion and hydrolysis. The rate equation derived from a model considering both the diffusion and hydrolysis processes can successfully predict the experimental results for several kinds of polymeric prodrugs. It is also shown that the diffusion coefficient and rate constant for hydrolysis calculated from this equation thoroughly express the character of the comonomer. The rate equation derived from the model that considers both diffusion and hydrolysis is very useful to analyze drug release from various kinds of polymeric prodrugs in a heterogeneous system.     

Telomerase activity in human bladder cancer

Telomerase can synthesize telomeric DNA repeats onto chromosome ends. Telomere length and telomerase activity have recently been implicated in the control of the proliferative capacity of normal and malignant cells. The expression of telomerase activity is concomitant with the attainment of immortality in tumor tissues and cells. Thus, enzyme activity may indicate a prevalent or even ubiquitous tumor producer. In this report, telomerase activity was analyzed in 40 human bladder cancers, 7 normal tissues, and 2 bladder epithelia with dysplasia using a PCR-based telomeric repeat amplification protocol assay. Telomerase activity was detected in almost all bladder tumors (97.5%); only one sample, which was in an early stage, did not express telomerase activity. None of the normal tissues displayed telomerase activity. One of the two bladder epithelia with dysplasia expressed low telomerase activity. The expression of telomerase activity has a clear association with the pathological grade and clinical stage. Most of the tumors with high telomerase activity were in an advanced grade and had deep invasion. Thus, telomerase activity might be suggested to represent an additional required event in the multigenetic process of tumorigenesis in human bladder cancer.