Detection of caspase-9 activation in the cell death of the Bcl-x-deficient mouse embryo nervous system by cleavage sites-directed antisera

Caspases, which play crucial roles during apoptosis, are activated from their inactive proforms in a sequential cascade of cleavage by other members of the caspase family. Caspase-9 is autoprocessed by the Apaf-1/cytochrome c pathway and acts at an early point in this cascade, whereas Bcl-xL, an antiapoptotic member of the Bcl-2 family, prevents activation of caspases in vitro. Little is known, however, about the relation between caspase-9 and Bcl-xL during development of the mammalian nervous system. We used antisera against two cleavage sites in mouse caspase-9 that recognize only the activated form of mouse caspase-9, and we examined immunohistochemically the activation of mouse caspase-9 in the nervous system of Bcl-x-deficient mouse embryos. Mouse caspase-9 is processed at both D(353) and D(368), but it is processed preferentially at D(368) during apoptosis of cultured cells induced by various stimuli and in the nervous system of Bcl-x-deficient mouse embryos. We show that Bcl-xL protects against caspase-9- and/or caspase-3-dependent apoptosis in the caudal portion of the ventral hindbrain, anterior horn cells, and dorsal root ganglia neurons of the normal mouse embryos and against caspase-9/caspase-3-independent apoptosis in the dorsal region of the nervous system including the dorsal spinal cord. Furthermore, we demonstrate that Bcl-xL blocks cytochrome c release from mitochondria, causing activation of caspase-9 in anterior horn cells and dorsal root ganglia neurons in mouse embryos at embryonic day 11.5.

Time-resolved two-dimensional thick-slice magnetic resonance digital subtraction angiography in assessing brain tumors

The aim of this study was to evaluate clinical applicability of two-dimensional (2D) thick-slice, contrast-enhanced magnetic resonance digital subtraction angiography (MRDSA) with high temporal resolution in diagnosis of brain tumors. Forty-four patients with brain tumors including, 15 meningiomas, 8 gliomas, 6 metastatic tumors, 4 neuromas, and 2 hemangioblastomas, were studied with 2D MRDSA with frame rate approximately 1 s. Images were continuously obtained following the initiation of bolus injection of gadolinium chelates for 40 s and subtraction images were generated in a workstation. We evaluated visualization of normal cranial vessels on MRDSA and compared MRDSA and intra-arterial digital subtraction angiography (IADSA) with regard to hemodynamic information. Large cerebral arteries, all venous sinuses, and most tributaries were clearly visualized. A stain was present in hypervascular tumors including all 15 meningiomas and 2 hemangioblastomas on MRDSA. Presence of a stain demonstrated on MRDSA and that on IADSA coincided in 16 of 20 cases (Spearman rank correlation value was 0.85). The location, shape, and phase of the stain on MRDSA were similar to those on IADSA. Two-dimensional MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics, such as IADSA, and can play an important role in assessing brain tumors.

Scaling analysis of the concentration dependence on elasticity of agarose gel

Since the critical exponent of the elastic modulus is related to the spatial dimension and the critical exponent of the correlation length, depending on the characteristics of elasticity, we experimentally evaluated both the elastic modulus of a sol-gel transition system and also the correlation length. We could determine the correlation length of agarose gel by the dynamic light scattering method; it was well described by the power law as a function of the deviation from the sol-gel transition point. Three scaling laws between the critical exponent of the correlation length (v) and that of the elastic shear modulus (t) were compared, and the critical exponent of the elastic modulus was described by the equation of de Gennes expression (t=1+v(d-2), where d is the spatial dimension). This result suggests that agarose fibers are stiff enough to show scalar elasticity.

The effect of 6-methylthiohexyl isothiocyanate isolated from Wasabia japonica (wasabi) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-buatnone-induced lung tumorigenesis in mice

The present study was undertaken to estimate the effect of 6-methylthiohexyl isothiocyanate (6MHITC) isolated from Wasabia japonica (wasabi) pretreatment on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone(NNK)-induced lung tumorigenesis in mice. Pretreatment with 6MHITC for 4 consecutive days at a daily dose of 5 micromol significantly inhibited NNK-induced O(6)-methylguanine formation in lungs at 4 h after the injection. In conjugation with this inhibitory effect, 6MHITC suppressed the increase in proliferating nuclear cell antigen level as well as ornithine decarboxylase activity at a promotion stage of NNK-induced lung tumorigenesis. Finally, this treatment of 6MHITC suppressed the NNK-induced lung tumorigenesis in mice. These results suggest that 6MHITC inhibits the development of lung tumors in mice treated with NNK, due to the suppression of initiation stage.

Detection of tumor cells in blood using CD45 magnetic cell separation followed by nested mutant allele-specific amplification of p53 and K-ras genes in patients with colorectal cancer

A new method for detecting circulating tumor cells that is based on magnetic-activated cell separation (MACS) and nested mutant allele-specific amplification (nested MASA) was evaluated in patients with colorectal cancer using the p53 and K-ras genes as genetic markers. By negative selection with anti-CD45 monoclonal antibody-conjugated supermagnetic microbeads, the proportion of tumor cells was enriched 9-fold. By the combination of MACS and nested MASA, 10 tumor cells in 10(7) normal peripheral blood mononuclear cells could be detected without false-positives. Using this method, we examined blood taken from the tumor drainage veins of 23 patients with colorectal cancer. Eighty-seven percent (20/23) of primary tumor tissues showed p53 and/or K-ras gene mutations. Forty-five percent (9/20) of patients with p53 and/or K-ras mutations in the primary tumor showed the same mutated genes in the blood samples. There was a significant association between the presence of p53 and K-ras gene mutation in the blood and tumor size, depth of invasion, and venous invasion. Blood gene mutation was detected in 80% (4/5) of samples from patients with synchronous liver metastases. Sixty percent (3/5) of patients with mutant genes in the blood developed asynchronous liver metastases after surgery. The overall survival of patients with p53 and/or K-ras gene mutation-positive findings in blood was significantly shorter than that of patients testing negative on Kaplan-Meier analysis. Our results suggest that the method may be useful for reliable detection of tumor cells circulating in the blood and may help to identify patients at high risk for relapse.

Identification of catalytic nucleophile of Escherichia coli gamma-glutamyltranspeptidase by gamma-monofluorophosphono derivative of glutamic acid: N-terminal thr-391 in small subunit is the nucleophile

gamma-Glutamyltranspeptidase (EC 2.3.2.2) is the enzyme involved in glutathione metabolism and catalyzes the hydrolysis and transpeptidation of gamma-glutamyl compounds such as glutathione and its derivatives. The reaction is thought to proceed via a gamma-glutamyl-enzyme intermediate where a hitherto unknown catalytic nucleophile is gamma-glutamylated. Neither affinity labeling nor site-directed mutagenesis of conserved amino acids has succeeded so far in identifying the catalytic nucleophile. We describe here the identification of the catalytic nucleophile of Escherichia coli gamma-glutamyltranspeptidase by a novel mechanism-based affinity labeling agent, 2-amino-4-(fluorophosphono)butanoic acid (1), a gamma-phosphonic acid monofluoride derivative of glutamic acid. Compound 1 rapidly inactivated the enzyme in a time-dependent manner (k(on) = 4.83 x 10(4) M(-1) s(-1)). The inactivation rate was decreased by increasing the concentration of the substrate. The inactivated enzyme did not regain its activity after prolonged dialysis, suggesting that 1 served as an active-site-directed affinity label by phosphonylating the putative catalytic nucleophile. Ion-spray mass spectrometric analyses revealed that one molecule of 1 phosphonylated one molecule of the small subunit. LC/MS experiments of the proteolytic digests of the phosphonylated small subunit identified the N-terminal peptide Thr391-Lys399 as the phosphonylation site. Subsequent MS/MS experiments of this peptide revealed that the phosphonylated residue was Thr-391, the N-terminal residue of the small subunit. We conclude that the N-terminal Thr-391 is the catalytic nucleophile of E. coli gamma-glutamyltranspeptidase. This result strongly suggests that gamma-glutamyltranspeptidase is a new member of the N-terminal nucleophile hydrolase family.

[A case of saccular aneurysm of the coronary artery post PTCA]

We experienced a 48-year-old man who was diagnosed as having a saccular aneurym of the coronary artery by CAG after an otherwise uneventful percutaneous transluminal coronary angioplasty (PTCA). At the time of operation, the aneurysm, measured 15 mm, and arose from the 3rd segment of the right coronary artery. Aneurysmal formation after successful PTCA is not rare and is related to the overinflating balloon. It is necessary to evaluate the coronary artery after PTCA by IVUS. There were no symptoms after the operation and he was discharged at 21th postoperative day.

Effect of water content on dielectric relaxation of gelatin in a glassy state

The dielectric properties of gelatin in the glassy state were measured from 100 Hz to 1 MHz over a temperature range of -20 to 60 degrees C. Samples with different water contents were prepared by varying the drying time for desalted gelatin solution; they were confirmed to be in the glassy state from DSC measurements. The dielectric relaxation (the decrease in dielectric constant, epsilon', and the maximum of the dielectric loss, epsilon' ') was observed for each sample; the relaxation time tau was evaluated from the peak of epsilon' '. The activation energy E obtained from an Arrhenius plot of tau decreased with increasing water content. On the basis of the order of magnitude of E, the dielectric relaxation observed was considered to be beta-relaxation reflecting the local motion of molecules. E and tau seem to describe the enhancement effect of water on the mobility of gelatin molecules in the glassy state; tau and E are considered to be suitable parameters for the characterization of the plasticizing effect of water on a glassy material.

Identification of novel membrane and secreted proteins upregulated during adipocyte differentiation

Adipose tissue is the largest organ in the body that secretes soluble proteins such as cytokines. A preadipocyte cell line 3T3-L1 has been widely used for investigations of mechanisms of adipocyte differentiation. 3T3-L1 cells convert to adipocytes in the presence of 1-methyl-3-isobutylxanthine, dexamethasone, and insulin. We screened a cDNA library derived from differentiated 3T3-L1 cells, using the SST-REX method (signal sequence trap by retrovirus-mediated expression screening method). Screening of 4 x 10(5) clones gave rise to 63 known and 8 novel clones. The known clones represented 28 independent proteins, 21 of which were secreted proteins and 7 were membrane proteins. The novel clones represented 7 independent proteins, 5 of which had no similarity to known proteins. Interestingly, most of these novel genes showed differentiation- and tissue-specific expression. The present results indicate that adipocytes specific genes or adipocyte differentiation-related genes encoding membrane and secreted proteins can be readily identified if signal sequence trap screening of differentiated adipocyte-derived cDNAs is done.

Minimally invasive direct coronary artery bypass grafting using the saphenous vein in redo CABG

We describe a patient who underwent minimally invasive direct coronary artery bypass (MIDCAB), who had previously undergone coronary artery bypass grafting (CABG) through a median sternotomy with a left internal mammary artery (LIMA) graft to the left anterior descending artery (LAD) and a right gastroepiploic artery (GEA) graft to the posterior descending artery. MIDCAB was less invasive and was an effective alternative procedure for the second operation. Because the patient had no LIMA or GEA available for a graft because of prior use, we used a saphenous vein graft (SVG) for bypassing from the left subclavian artery to the coronary artery by MIDCAB via a left minithoracotomy. The left subclavian artery was selected as the proximal anastomotic site because this artery was less diseased and was easier to reach. The SVG-to-coronary artery anastomosis was facilitated by firm adhesion between the epicardium and the pericardium, which reduced the motion of the epicardium itself. These results suggest that the procedure is safe and promising in selected cases of redo CABG.

Detection of hepatocellular carcinoma and its metastases with various pulse sequences using superparamagnetic iron oxide (SHU-555-A)

BACKGROUND

To identify the most useful combinations of various pre- and postcontrast magnetic resonance (MR) image sequences in detecting hepatocellular carcinoma (HCC) and its intrahepatic metastases before and after injection of SHU-555-A.

METHODS

Thirty-eight lesions in 16 patients were evaluated before and after administration of SHU-555-A by using fast spin echo (FSE), gradient echo (GRE), and echo planar (EP) imaging sequences using a 1.5-Tesla superconducting MR system. The signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) of the lesions, signal-to-noise ratios, and other parameters were calculated.

RESULTS

Tumors were better detected after injection of SHU-555-A on all pulse sequences except on out-of-phase T1-weighted (T1W)-GRE sequences. Tumor detectability was higher for precontrast EP imaging and T2*-weighted (T2*W)-GRE sequences, whereas detectability at postcontrast was higher for T2*W-GRE, proton-density-weighted-FSE, and in-phase T1W-GRE sequences. The SIR and CNR at precontrast were highest for EP imaging, and those at postcontrast were highest for T2*W-GRE.

CONCLUSION

SHU-555-A will increase the detectability of HCC and its liver metastases. T1W- and T2*W-GRE sequences would be the sequences of choice.

Purification, cloning, and three-dimensional structure prediction of Micrococcus luteus FAD-containing tyramine oxidase

The FAD-containing tyramine oxidase enzyme and gene from the Gram (+) bacterium Micrococcus luteus were isolated, and computer prediction was used to propose a preliminary 3D model of the protein. A 2.8-kb Sau3AI fragment containing the structural gene of tyramine oxidase was cloned from a M. luteus genomic DNA library. The 1332 bp gene encodes a protein of 443 amino acids, with a calculated molecular mass of 49.1 kDa. The enzyme was found to be a homodimer with a molecular weight of 49,000. It oxidizes tyramine, adrenaline, 3-hydroxytyramine, dopamine, and noradrenaline, and was reversibly inhibited by FAD-containing monoamine oxidase A and B specific inhibitors. Sequence comparison show that tyramine oxidase is smaller than other FAD-amine oxidases but that it contains well-conserved amino acid residues reported in all other FAD-amine oxidases. A hypothetical three-dimensional structure of tyramine oxidase has also been proposed based on secondary structure predictions, threading, and comparative modeling.

Standardized thigh muscle area measured by computed axial tomography as an alternate muscle mass index for nutritional assessment of hemodialysis patients

BACKGROUND

Quantification of muscle mass, which represents the largest protein pool in the body, is important for nutritional assessment but is difficult to achieve with conventional methods in hemodialysis patients.

OBJECTIVE

We measured the cross-sectional area of the thigh occupied by muscle by using computed tomography and compared this with other muscle mass indicators.

DESIGN

Thigh muscle area (TMA) was examined and correlated with creatinine production and various nutritional indexes in 163 patients undergoing hemodialysis. Where appropriate, TMA was expressed relative to bone area in the thigh (TBA) to avoid the influence of body size.

RESULTS

TMA was highly correlated with creatinine production as measured in the spent dialysate (r = 0.85, P < 0.001), indicating that TMA substantially reflects total-body muscle mass. TMA standardized for TBA was negatively correlated with age and positively correlated with other nutritional indicators including body weight, body mass index, serum albumin, serum transthyretin, and protein catabolic rate. Multiple regression analysis revealed that of these variables, age, serum albumin, and protein catabolic rate independently predicted TMA standardized for TBA. By using correlations with various nutritional indicators, we concluded that patients with a value <10.0 for TMA standardized for TBA were likely to be malnourished whereas those with a value >13.0 were likely to be well nourished.

CONCLUSIONS

These results indicate that TMA standardized for TBA, measured by computed tomography, is a reliable indicator of muscle mass that could be used for nutritional assessment of hemodialysis patients.

Dynamic contrast-enhanced MR angiography and MR imaging of the carotid artery: high-resolution sequences in different acquisition planes

BACKGROUND AND PURPOSE

First-pass contrast-enhanced MR angiography has become the technique of choice for studying the carotid bifurcation, but this method has some limitations. We evaluated the clinical utility of performing 3D contrast-enhanced MR angiography in the axial plane immediately after performing angiography in the coronal plane.

METHODS

Cervical carotid arteries of 80 consecutive patients were studied on a 1.5-T MR imager with phased-array coils. Coronal 3D MR angiography was performed after administering a bolus injection of contrast material (20 mL) with automatic triggering. This was immediately followed by an axial acquisition. We measured carotid diameters on the contrast-enhanced MR angiograms as well as on intra-arterial digital subtraction angiograms according to established criteria. We also evaluated original source MR angiograms.

RESULTS

Angiograms obtained in the axial plane correlated better with the intra-arterial digital subtraction angiograms than did the coronal angiograms. When first-pass contrast-enhanced MR angiography was incomplete because of a failure of triggering, the second-phase acquisition provided sufficient image quality. Original source images suffered from ring artifacts, low axial resolution, and a low level of soft-tissue visualization. Axial-based source images showed flow-independent contrast filling to the patent lumen with sufficient visualization of plaque morphology, thickened arterial wall, and surrounding disease processes, such as tumors.

CONCLUSION

With the addition of a 1-minute second-phase 3D acquisition in a different plane immediately after first-pass contrast-enhanced MR angiography, one can obtain a more accurate depiction of the carotid bifurcation, insurance against failure of triggering, and diagnostic source images.

Interactions between thermal cycled resilient denture lining materials, salivary and serum pellicles and Candida albicans in vitro. Part II. Effects on fungal colonization

In the present study, the growth of a single isolate of Candida albicans on saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) seven commercial soft lining materials were investigated, by adenosine triphosphate (ATP) analysis. In the case of control resilient liners (not thermocycled and uncoated), the fungal colonization appeared to depend upon the type of commercial resilient liner used. Thus, the lowest colonization was observed with fluoric and heat-cured silicone materials, cold-cured silicone materials, except for one product, and heat-cured acrylic resin exhibited the highest colonization capacity, and cold-cured acrylic resilient liners exhibited the intermediate. However, the fungal colonization on the materials was significantly promoted both by thermal cycling (ANOVA, P<0.01) and a layer of protein coating (saliva, P<0.01; serum, P<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host promote yeast colonization on resilient lining materials.

Characterization of endo-alpha-N-acetylgalactosaminidase from Bacillus sp. and syntheses of neo-oligosaccharides using its transglycosylation activity

Endo-alpha-N-acetylgalactosaminidase was purified to homogeneity from the culture fluid of Bacillus sp. isolated from soil and characterized. The molecular mass of the enzyme was estimated as 110 kDa. The enzyme was stable at pH 4.0-10.0, up to 55 degrees C, and was most active at pH 5.0. The substrate specificity of the enzyme was strict for the disaccharide, galactosyl beta1, 3 N-acetyl-d-galactosamine, bound to aglycone in alpha configuration. On the other hand, the specificity of the enzyme for the aglycone structure was fairly relaxed. The enzyme could transfer the disaccharide from para-nitrophenyl substrate to various acceptors, such as monosaccharides, disaccharides, and sugar alcohols. Using this transglycosylation activity of the endoglycosidase, it may be possible to synthesize neo-oligosaccharides.

GPR1 regulates filamentous growth through FLO11 in yeast Saccharomyces cerevisiae

Cell growth and differentiation are regulated by nutrient availability in the yeast Saccharomyces cerevisiae. Under conditions of nitrogen limitation, diploid cells of S. cerevisiae differentiate to a filamentous growth known as a pseudohyphal growth, while haploid cells produce invasive filaments which penetrate the agar in nutrient-rich medium. We have found that GPR1, which encodes a putative G-protein-coupled receptor, is required for both pseudohyphal and invasive growth. Pseudohyphal growth was defective in Deltagpr1/Deltagpr1 mutant strain and this defect was reversed by addition of cAMP. Also, haploid Deltagpr1 mutant strain was defective in invasive growth. Northern blot analysis revealed that the transcriptional level of FLO11, which encodes a recently identified cell surface flocculin required for pseudohyphal growth, was reduced in Deltagpr1 mutant strain. These results indicate that GPR1 regulates both pseudohyphal and invasive growth by a cAMP-dependent mechanism.

Conductance and relaxations of gelatin films in glassy and rubbery states

The dielectric constant, epsilon', and the dielectric loss, epsilon'', for gelatin films were measured in the glassy and rubbery states over a frequency range from 20 Hz to 10 MHz; epsilon' and epsilon'' were transformed into M* formalism (M* = 1/(epsilon' - i epsilon'') = M' + iM''; i, the imaginary unit). The peak of epsilon'' was masked probably due to dc conduction, but the peak of M'', e.g. the conductivity relaxation, for the gelatin used was observed. By fitting the M'' data to the Havriliak-Negami type equation, the relaxation time, tauHN, was evaluated. The value of the activation energy, Etau, evaluated from an Arrhenius plot of 1/tauHN, agreed well with that of Esigma evaluated from the DC conductivity sigma0 both in the glassy and rubbery states, indicating that the conductivity relaxation observed for the gelatin films was ascribed to ionic conduction. The value of the activation energy in the glassy state was larger than that in the rubbery state.

Application of nitrifying and denitrifying processes to waste management of aquatic life support in space

Since a biological filter with nitrifying bacteria was firstly applied to aquatic animal experiments in IML-2 mission, the reactor system has been further studied to combine both nitrifying and denitrifying reactions under aerobic environment allowing an efficient removal of inorganic nitrogen from animal wastes. The isolated denitrifying bacteria had an activity under aerobic condition with rice straw providing a metabolic carbon source for the reaction. The advantage of the aerobic biological filter having both nitrifying and denitrifying activities may allow to reduce the size of the life support system and also for its manageability. The paper reports characteristics of the biological filter systems used for the IML-2 mission and the improved combined filter system having both nitrifying and denitrifying activities, and discuss its application to space experiments.

Expression system for foreign genes using the fission yeast Schizosaccharomyces pombe

Foreign-gene expression systems using mammalian cells, Escherichia coli, insect cells, yeast and other organisms as hosts have been developed. The demand for protein-production systems will be further increased in basic research, medical science and the biotechnological industry. Systems using the fission yeast Schizosaccharomyces pombe as a host have only recently received attention. The advantages of this yeast, which is more advanced evolutionarily than other types of yeast, the expression vectors available and examples of heterologous protein produced with this system, are reviewed here.

Occlusal force distribution on the dental arch during various levels of clenching

The purpose of this study was to explore the occlusal force distribution on the dental arch in the intercuspal position and to evaluate the relationship between the clenching strength and the occlusal force distribution. These variables were recorded using the Dental Prescale System in 16 healthy young adults. The number of tooth contacts, occlusal force and occlusal contact area increased linearly as clenching strength increased. The distribution of the occlusal force was greatest at the molar region followed by the premolar and anterior teeth region. The proportion of occlusal force (occlusal force at each region/total occlusal force) on molar regions increased as clenching strength increased. On the contrary, the proportion of occlusal force on the premolar and anterior teeth regions decreased as clenching strength increased. These findings suggest that control of occlusal force is important in diagnosis of the nature of occlusal contacts.