Characteristics of a real-time radiation exposure dosimetry system using a synthetic ruby for radiotherapy

Radiotherapy-related medical accidents are frequently caused by planning problems, excessive irradiation during radiotherapy, or patient movement. This is partly because the local exposure dose cannot be directly monitored during radiotherapy. This article discusses the development of our recent real-time radiation exposure dosimetry system that uses a synthetic ruby for radiation therapy. Background noise was observed before the measurement of the short-term characteristic features. Regarding the relationship between the number of photons and dose rate, using 100 monitor units (MU)/min as the measurement value, the counts decreased by approximately 10% at 600 MU/min. A clear correlation was observed between the MU value and the number of photons (R² = 0.9987). The coefficient of variation (%CV) was less than ± 1.0% under all the irradiation conditions. Slight differences were observed between the ion chamber and the synthetic ruby dosimeters in the measurement of the percentage depth dose. However, this difference was almost matched by correcting for the Cherenkov light. Although some problems were observed with the synthetic ruby dosimeter system, our results indicate that the developed dosimeter can be used to measure the irradiation dose of patients in real time, with no significant impact on the data, as any effect would be masked by the larger effect of the ruby; however, the impact requires a detailed assessment in the future.

[Evaluation of AEC Consistency in Digital X-ray Imaging Systems]

The Japan Network for Research and Information on Medical Exposures (J-RIME) established the diagnostic reference level (DRL) and is advancing optimization of radiation protection. We believe that the difference in the imaging dose between facilities may be due to the fact that automatic exposure control (AEC) adjustment is not unified among manufacturers. The consistency of AEC is specified in JIS 4751-2-54, but it is not applicable to digital X-ray imaging systems because it is for optical density of analog X-ray imaging systems. This article evaluates the consistency of AEC in digital X-ray imaging systems. The AEC consistency was compared with the AEC-estimated dose from the air kerma (K_AEC) using the phosphor-based imaging plate placed at the back of the AEC detector. We measured the AEC tube voltage and subject thickness characteristics (tracking) of four types of digital X-ray imaging systems at three facilities. In the test of tube voltage characteristics, the average K_AEC values at all tube voltages were 2.37±0.04  µGy for A system, 7.30±1.44  µGy for B system, 3.53±0.13  µGy for C system, and 5.70±0.18  µGy for D system. The relative errors were +2.6 to -1.8% for A system, +25.3 to -22.6% for B system, +5.2 to -1.4% for C system, and +2.5 to -4.4% for D system. In the subject thickness characteristics test, the average K_AEC values for all Al thicknesses were 2.34±0.02  µGy for A system, 5.95±0.23  µGy for B system, 4.25±1.12  µGy for C system, and 5.03±1.27  µGy for D system. The relative errors were +1.0 to -0.9% for A system, +4.1 to -5.0% for B system, +40.5 to -28.1% for C system, and +19.7 to -42.9% for D system.

Clinical characteristics of lupus enteritis in Japanese patients: the large intestine-dominant type has features of intestinal pseudo-obstruction

This study was performed to investigate the clinical characteristics of lupus enteritis in Japanese patients with systemic lupus erythematosus (SLE). A total of 481 patients with SLE admitted to our hospital between 2001 and 2015 were retrospectively reviewed. Diagnosis of lupus enteritis was based on the following three criteria: (1) abdominal symptoms, (2) diffuse long-segment bowel thickening and (3) a requirement for glucocorticoid therapy. Lupus enteritis was identified in 17 patients (3.5%) and there were two distinct types: small intestine-dominant and large intestine-dominant. Significant differences between the two types were noted with respect to the age, frequency of biopsy-proven lupus nephritis, frequency of rectal involvement, maximum bowel wall thickness, and requirement for steroid pulse therapy. Among patients with large intestine-dominant lupus enteritis, 60% had extra-intestinal symptoms (hydroureter, bladder wall thickening, and bile duct dilatation) that are known complications of intestinal pseudo-obstruction. Two patients with large intestine-dominant lupus enteritis developed intestinal pseudo-obstruction either before or after diagnosis of lupus enteritis. Five patients (29%) developed recurrence during a median observation period of 7.2 years (1.4-14.4 years). In conclusion, large intestine-dominant lupus enteritis resembles intestinal pseudo-obstruction and these two diseases may have a common pathogenesis.

Ultrasonography of Thymoma with Pathologic Correlation

Preoperative ultrasonograms of 11 surgically proved thymomas and ex vivo ultrasonograms of 3 resected specimens were compared with pathologic findings of resected specimens. Among 11 thymomas 7 appeared solid, 3 were solid with several cystic regions, and the remaining one was unilocular cystic in appearance. Cystic regions on ultrasonograms corresponded to cystic changes on pathologic specimens. Six malignant thymomas showed a typical lacy appearance on ultrasonograms, which corresponded to the lobulated configuration separated by fibrous septa shown on the pathologic specimens.

Abundance of Virus-Sized Non-DNase-Digestible DNA (Coated DNA) in Eutrophic Seawater

Total DNA concentration in 0.2-mum-pore-size Nuclepore filter filtrates (<0.2-mum fraction) of Tokyo Bay water was estimated to be 9 to 19 ng/ml by an immunochemical quantification method. Almost 90% of the DNA in the <0.2-mum fraction was found in the size fractions larger than 3.0 x 10 Da and 0.03 mum, and most was not susceptible to DNase digestion, that is, consisted of non-DNase-digestible DNA (coated DNA). A significant amount of DNA was obtained from the <0.2-mum fraction of the seawater by three different methods: polyethylene glycol precipitation, direct ethanol precipitation, and ultrafilter concentration. Gel electrophoresis analysis of the isolated DNAs showed that they consisted mainly of coated DNAs with a similar molecular sizes (20 to 30 kb [1.3 x 10 to 2.0 x 10 Da). The abundance of the ultramicron virus-sized coated DNA in natural seawater suggests that these DNA-rich particles can be attributed to marine DNA virus assemblages and that they may be a significant phosphorus reservoir in the environment.

Activities and distribution of methanogenic and methane-oxidizing microbes in marine sediments from the Cascadia Margin

We investigated methane production and oxidation and the depth distribution and phylogenetic affiliation of a functional gene for methanogenesis, methyl coenzyme M reductase subunit A (mcrA), at two sites of the Integrated Ocean Drilling Program Expedition 311. These sites, U1327 and U1329, are respectively inside and outside the area of gas hydrate distribution on the Cascadia Margin. Radiotracer experiments using (14)C-labelled substrates indicated high potential methane production rates in hydrate-bearing sediments [128-223 m below seafloor (mbsf)] at U1327 and in sediments between 70 and 140 mbsf at U1329. Tracer-free experiments indicated high cumulative methane production in sediments within and below the gas hydrate layer at U1327 and in sediments below 70 mbsf at U1329. Stable tracer experiments using (13)C-labelled methane showed high potential methane oxidation rates in near-surface sediments and in sediments deeper than 100 mbsf at both sites. Results of polymerase chain reaction amplification of mcrA in DNA were mostly consistent with methane production: relatively strong mcrA amplification was detected in the gas hydrate-bearing sediments at U1327, whereas at U1329, it was mainly detected in sediments from around the bottom-simulating reflector (126 mbsf). Phylogenetic analysis of mcrA separated it into four phylotype clusters: two clusters of methanogens, Methanosarcinales and Methanobacteriales, and two clusters of anaerobic methanotrophic archaea, ANME-I and ANME-II groups, supporting the activity measurement results. These results reveal that in situ methanogenesis in deep sediments probably contributes to gas hydrate formation and are inconsistent with the geochemical model that microbial methane currently being generated in shallow sediments migrates downward and contributes to the hydrate formation. At Site U1327, gas hydrates occurred in turbidite sediments, which were absent at Site U1329, suggesting that a geological setting suitable for a gas hydrate reservoir is more important for the accumulation of gas hydrate than microbiological properties.

16S rRNA gene sequence-based analysis of clostridia related to conversion of germfree mice to the normal state

AIMS

To determine phylogenetic groups of clostridia inhabiting the mouse intestine that are essential for normalization of germfree (GF) mice.

METHODS AND RESULTS

Using both the culture method and cloning, clostridia inhabiting the mouse intestine were isolated, and phylogenetic analysis based on 16S rRNA gene sequences was carried out. As a result, the isolates were found to have novel sequences, and no isolate was determined to be identical to previously known identified clostridia. Although the taxonomy of mouse intestinal clostridia was complex, many of them belonged to Clostridium clusters XIVa and IV in conventional (CV) and limited flora mice and ex-germfree mice administered chloroform-treated CV mouse faeces. The clostridia that belonged to cluster XIVa were most often present and showed the highest diversity.

CONCLUSIONS

Clostridia belonging clusters XIVa and IV are dominant in the mouse intestine as in other gut ecosystems. The novel groups in these clusters are essential for normalization of GF mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study can be applied in the strict control of mouse intestinal microbiota and will provide important information for normalization of GF mice and also for research on microbiology of the mouse intestine.

Age-related three-dimensional morphological changes in rat motoneurons innervating diaphragm and longissimus muscles

We investigated age-related morphological changes of rat motoneurons innervating diaphragm muscle (DI-MN) and lumber longissimus muscle (LL-MN) in which quite different activation patterns exist. In young (2-4 months) and old (24-26 months) rats, the motoneurons innervating both muscles were labelled retrogradely by intramuscular injection of cholera toxin B subunit. After a 4-day survival, horizontal slices of the spinal cord were processed with immunohistochemical staining (first antibody to cholera toxin B subunit and second antibody with Cy3) and observed with a confocal microscope. Three-dimensional reconstruction of labelled motoneurons was performed to examine soma and dendrite morphology. As compared to the soma volume in young rats, significantly smaller values were found in old rats in both motoneurons and the degrees of decline were 16.1% in DI-MN and 20.3% in LL-MN. Significant decreases in the thickness of primary dendrites were also found in both motoneurons, and the degrees of decline were 17.5% in DI-MN and 22.3% in LL-MN. Smaller changes were found in DI-MN than in LL-MN, indicating the possibility that increased activation by central drives can attenuate age-related morphological changes of the motor system in the spinal cord.

Spatial and temporal distribution of the vibrionaceae in coastal waters of Hawaii, Australia, and France

Relatively little is known about large-scale spatial and temporal fluctuations in bacterioplankton, especially within the bacterial families. In general, however, a number of abiotic factors (namely, nutrients and temperature) appear to influence distribution. Community dynamics within the Vibrionaceae are of particular interest to biologists because this family contains a number of important pathogenic, commensal, and mutualist species. Of special interest to this study is the mutualism between sepiolid squids and Vibrio fischeri and Vibrio logei, where host squids seed surrounding waters daily with their bacterial partners. This study seeks to examine the spatial and temporal distribution of the Vibrionaceae with respect to V. fischeri and V. logei in Hawaii, southeastern Australia, and southern France sampling sites. In particular, we examine how the presence of sepiolid squid hosts influences community population structure within the Vibrionaceae. We found that abiotic (temperature) and biotic (host distribution) factors both influence population dynamics. In Hawaii, three sites within squid host habitat contained communities of Vibrionaceae with higher proportions of V. fischeri. In Australia, V. fischeri numbers at host collection sites were greater than other populations; however, there were no spatial or temporal patterns seen at other sample sites. In France, host presence did not appear to influence Vibrio communities, although sampled populations were significantly greater in the winter than summer sampling periods. Results of this study demonstrate the importance of understanding how both abiotic and biotic factors interact to influence bacterial community structure within the Vibrionaceae.

Determinants for Prediction of Malignant Potential by Metalloproteinase:E-Cadherin Ratio in Prostate Core Needle Biopsy

According to a good correlation between in situ hybridization-based metalloproteinase-2/9:E-cadherin ratio (MER) and the pathological stage of prostate cancer, we set the cutoff line of MER at 6.0 (MER>6) to distinguish between organ-confined (pT2) and advanced diseases (pT3a-b/N1). In this study, we looked at the factors affecting MER and leading to a misprediction of the pathological stage. We examined MER in 39 paired specimens of prostate core needle biopsy and prostatectomy from the same patient and compared these MERs. In 34 (87%) of 39 cases, the MER of biopsy was correlated with the final pathological stage (pT2 vs. pT3a-b/N1). MER ranges in pT3a-b/N1 cancer were significantly wider than those in pT2 cancer (p < 0.01). The number of MER>6 fields in Gleason score 8-9 cancer was larger than that in Gleason score 7 cancer (p < 0.0001). In 5 cases where there was a failure to distinguish pT2 from pT3a-b/N1, the misdiagnosis was significantly associated with a small number of biopsies (4 or 6 specimens; p = 0.0469), a small amount of tumor tissue in biopsy specimens (less than 5 mm; p = 0.0492), and a wide MER range (more than 5.0; high intratumoral heterogeneity; p = 0.0202). Considering these factors increases the usefulness of preoperative prediction of the final pathological stage by MER in prostate cancer.

pH-sensing nano-crystals of carbonate apatite: effects on intracellular delivery and release of DNA for efficient expression into mammalian cells

Two unique and fascinating properties of carbonate apatite which are well-known in hard tissue engineering, have been unveiled, for the first time, for the development of the simplest, but most efficient non-viral gene delivery device - ability of preventing the growth of crystals needed for high frequency DNA transfer across a plasma membrane and a fast dissolution rate for effective release of DNA during endosomal acidification, leading to a remarkably high transgene expression (5 to 100-fold) in mammalian cells compared to the widely used transfecting agents. Moreover, by modulating the crystal dissolution rate of carbonate apatite through incorporation of fluoride or strontium into it, transfection activity could be dramatically controlled, thus shedding light on a new barrier in the non-viral route, which was overlooked so far. Thus we have developed an innovative technology with significant insights, that would come as a promising tool for both basic research laboratories and clinical settings.

Brain-derived neurotrophic factor increases inhibitory synapses, revealed in solitary neurons cultured from rat visual cortex

To elucidate chronic actions of brain-derived neurotrophic factor (BDNF) on GABAergic synapses, we examined effects of a long-term application of BDNF for 10-15 days on autapses (synapses) of solitary GABAergic neurons cultured from rat visual cortex. Solitary neuron preparations were used to exclude a possible contamination of BDNF actions on excitatory neurons in dissociated neuron culture or slice preparations. Neurons were confirmed to be GABAergic pharmacologically with bicuculline, a selective antagonist for GABAA receptors and immunocytochemically with antibody against glutamic acid decarboxylase 65, a GABA synthesizing enzyme. To evaluate GABAergic synaptic function, evoked and/or miniature inhibitory postsynaptic currents (IPSCs) were recorded in the whole-cell voltage-clamp mode. The treatment with BDNF at a concentration of 100 ng/ml enhanced the amplitude of evoked IPSCs and the frequency of miniature IPSCs. In contrast, BDNF did not have a detectable effect on the amplitude of miniature IPSCs and the paired pulse ratio of IPSCs evoked by two, successive activations. To evaluate morphological changes, neurons were immunocytochemically stained with antibodies against microtubule-associated protein 2, to visualize somatodendritic region and synapsin I, to visualize presynaptic sites. The quantitative analysis indicated that BDNF increased the area of soma, the numbers of primary dendrites and dendritic branching points, the total length of dendrites and the number of synaptic sites. Such an action of BDNF was seen in both subgroups of GABAergic neurons, parvalbumin-positive and -negative neurons. To visualize functionally active presynaptic sites, neurons were stained with a styryl dye, FM1-43. BDNF increased the number of stained sites that was correlated with the frequency of miniature IPSCs. These results suggest that the chronic treatment with BDNF promotes dendritic and synaptic development of GABAergic neurons in visual cortex.

Dynamics of microbial populations and strong selection for Cycloclasticus pugetii following the Nakhodka oil spill

Microbial population changes were monitored immediately after the Nakhodka oil spill accident in January 1997 at the heavily oil-contaminated Mikuni coast along the Sea of Japan. The total cell number was almost stable for one year at 2-5 x 10(5) cells mL(-1), while the relative occurrence of culturable heterotrophs and degraders of oil components such as C-heavy oil, kerosene, and n-tetradecane varied, showing a maximum (>50% of the total) immediately following the accident. Gene amplification and phylogenetic analysis of a dilution culture using C-heavy oil as the sole carbon and energy source revealed that one of the predominant oil degraders at the oil-contaminated coast in 2 weeks after the accident closely resembled the aromatic hydrocarbon decomposer Cycloclasticus pugetii. Microbial community composition in oil-contaminated seawater was estimated at the molecular level using newly developed oligonucleotide probes, probe wash-off curve estimation, and quantitative fluorescence dot-blot hybridization techniques. At two different oil-polluted sites, harbor and intertidal regions, the C. pugetii group was estimated to make up 23-25% of the total Bacteria population, followed by the aliphatic hydrocarbon decomposer Alcanivorax borkumensis, which formed 4-7% of the Bacteria. In incubation experiments using floated oil slick and indigenous microbes collected at the harbor, oil degradation activities were enhanced by the addition of both organic and inorganic nutrients. Significant decreases were found in aromatic and aliphatic hydrocarbon fractions: 54-60% and 22-24% in 2 weeks to 68-77% and 23-32% in 2 months, respectively.

Triplex formation using ODN conjugates with polycation comb-type copolymer

Polycation comb-type copolymer that is composed of polylysine backbone and dextran side chains (PLL-g-Dex) has previously been shown to stabilize duplex and triplex DNAs quite effectively. In this study, we have conjugated PLL-g-Dex with oligonucleotides (ODN) aiming to increase the triplex stabilizing efficiency of the copolymer. Here we have demonstrated that the copolymer-TFO conjugates selectively stabilize triplex DNA. Also its potential to form triplex DNA was found to be greater than PLL-g-Dex/ODN mixture.

Acceleration of DNA strand exchange by polycation comb-type copolymer

The accelerating effect of cationic substances on DNA strand exchange reaction between 20 bp DNA duplex and its complementary single strand was studied. A comb-type polycationic copolymer which is composed of poly (L-lysine) backbone and dextran graft chain (PLL-g-Dex) and known to stabilize triplex DNA expedites the strand exchange reaction under physiological relevant conditions. Electrostatically small excess of the copolymer increased DNA strand exchange rate by 300-fold while large excess of spermine or cethyltrimethylammonium bromide, cationic detergent known to promote markedly hybridization of complementary DNA strands, showed slight effect. It should be noted that the copolymer promotes the strand exchange reaction while it stabilizes double stranded DNA.

Synergistic stabilization of triplex by combination of comb-type cationic copolymer and oligo-N3'-->P5' phosphoramidates

In the present study, we describe rapid formation of stable pyrimidine motif triplex at physiological pH. The triplex formation was achieved by the synergistic effect of poly(L-lysine)-graft-dextran (PLL-g-Dex) copolymer and N3'-->P5' phosphoramidate (PN) backbone modification of triplex-forming oligonucleotide (TFO). Either the PLL-g-Dex copolymer or the PN modification alone increased the binding constant by nearly two orders of magnitude for the triplex formation at neutral pH. The combination of both stabilizing factors that was the triplex formation with the PN TFO in the presence of the copolymer increased the binding constant by nearly four orders of magnitude. The kinetic study indicated that the copolymer increased the association rate constant, whereas the PN modification decreased the dissociation rate constant. No negative interference between these stabilizing effects was observed. The kinetically orchestrated effects in which the copolymer and the PN TFO contribute to distinct ingredients in triplex equilibrium achieved the rapid formation of the stable triplex.

Protein/oligonucleotide conjugates as a cell specific PNA carrier

We have focused on proteineus ligand conjugate with oligonucleotides (ODNs) as a cell-specific delivery vector for peptide nucleic acids (PNAs). Asialofetuin (AF), a hepatocyte-specific proteineus ligand, was conjugated with ODNs that served as binding sites for PNAs. Succinimidyl-transe-4(N-maleimidylmethyl)-cyclohexane-1-carboxylate (SMCC) modified AF was coupled with 5'-thiolated oligodeoxynucleotide (HS-ODN). The resulting conjugate held PNAs with sequence-specific manner. The PNA/DNA conjugate complex has resistance against nucleases in serum. The efficient release of PNA from the complex was observed when the complex was made in contact with a target nucleotide. PNA uptake to hepatocytes was greatly enhanced when hepatocytes was incubated with PNA/conjugate complex. Free AF thoroughly inhibited PNA uptake with the conjugate, evidencing asialoglycoprotein receptor (ASGP-R) mediated endocytosis to be a major-route for the cellular uptake.

Polycation graft copolymers accelerating DNA strand exchange: involvement of ionic interaction

In the previous study (Chem. Eur. J., 7, 176 (2001)) we demonstrated that the comb-type polycationic copolymer (PLL-g-Dex) which is composed of poly (L-lysine) backbone and dextran graft chains expedited the DNA strand exchange reaction. In this study, fluorescence resonance energy transfer (FRET) was employed to explore the copolymer-mediated DNA strand exchange with higher time-resolution. To initiate strand exchange reaction the duplex prepared from 3'-fluorescein isothiocyanate (FITC)--and 5'-carboxytetramethylrhodamine(TAMRA)-labeled complementary DNAs was added to its non-labeled complementary single strand. DNA strand exchange was monitored by observing the recovery of the FITC quenching. More than 20,000 times increase in strand exchange rate at 37 degrees C by the copolymer was estimated. To investigate the accelerating mechanisms of the copolymer, the same reactions but at various ionic strenghts were studied. With increasing ionic strengths the strand exchange rate in the absence of the copolymer increased, suggesting that ionic repulsion among DNAs is unfavorable for the strand exchange to occur. Hence, alleviation of the electrostatic repulsion through interpolyelectrolyte complex formation is probably a role of the copolymer for accelerating the strand exchange reaction.

Cancer history and loss of MSH2 and MLH1 protein expression in patients with endometrial hyperplasia

In order to evaluate the hereditary background of endometrial hyperplasia patients in relation to protein expression of DNA mismatch repair genes, we evaluated 69 patients with endometrial hyperplasia and 18 patients with normal endometrium having both a personal and family history of cancer (two hereditary nonpolypoid colorectal cancer (HNPCC) patients). We obtained personal and family histories of cancer for all patients. MSH2 and MLH1 protein expression was investigated by immunohistochemical methods. In the endometrial hyperplasia patients, 11 had personal histories and 40 had family histories of cancer. Among the 11 endometrial hyperplasia patients with a personal history of cancer, most cancers were breast or colorectal cancers (82%). In the 40 patients with a family history of cancer, colorectal cancer (33%) was the most frequent. The incidence of loss of expression of MSH2 and/or MLH1 protein in endometrial hyperplasia patients with personal (64%) or family (40%) histories was significantly higher than that in patients without such history (no personal: 21% and no family: 10%; P = 0.0035 and 0.0065). No protein loss was detected in any of the cases with normal endometrium having either a personal or family history of cancer. Our results suggest that a portion of endometrial hyperplasia cases having a personal or family history of cancer may belong to HNPCC, and that in these cases, abnormality of the mismatch repair system may be an early event in endometrial carcinogenesis.

Long-term follow-up of hepatitis C virus infection: HLA class II loci influences the natural history of the disease

Hepatitis C virus (HCV) causes various grades of chronic liver disease, ranging from an asymptomatic state to cirrhosis. To assess genetic factors of disease severity, we selected two HCV patient groups according to the following stringent criteria: (i) asymptomatic carrier state (ASC) defined by HCV infection for more than 20 years, normal alanine aminotransferase levels for the past 5 years as well as normal liver histology and/or shape and (ii) liver cirrhosis (LC) as diagnosed by clinical symptoms, liver biopsy and/or ultrasonography. A total of 103 chronically infected Japanese HCV patients (43 ASC and 60 LC) were analyzed. HLA class I and II alleles were established using low resolution DNA typing. HLA-DRB1 and DQB1 genotypes were inferred upon polymerase chain reaction-restriction fragment length polymorphism analysis. Two hundred and one anti-HCV-negative ethnically matched controls were included. The frequencies of DRB1*12 (*1201 and *1202), DQB1*0301 and DRB3*03 alleles were higher in patients with ASC than in those with LC (odds ratio (OR) 11.23, OR 4.25, and OR 3.22, respectively). The frequency of DQB1*0503 were lower in ASC patients compared to LC patients (OR 0.05). No significant differences between groups were observed for age, sex, source of infection, HCV genotype or viral loads. Our findings establish that certain HLA class II alleles strongly influence disease progression following HCV infection.

Inhibition of sequence-specific protein-DNA interaction and restriction endonuclease cleavage via triplex stabilization by poly(L-lysine)-graft-dextran copolymer

Triplex stabilization by poly(L-lysine)-graft-dextran copolymer within a mammalian gene promoter inhibits the DNA binding activity of nuclear proteins from HeLa cells as well as restriction endonuclease cleavage at physiological pH and ionic conditions in vitro. Electrophoretic mobility shift assays using a 30-mer homopurine-homopyrimidine stretch (located between -170 and -141 bp) of rat alpha 1 (I) collagen gene promoter reveal that the copolymer, at its wide range of charge ratio with DNA, stabilizes triplex DNA and enhances triplex-specific inhibition of the protein-DNA interaction. When the triplex-forming region (located between -165 and -146 bp) of the promoter is engineered at the Bam H1 and Pst 1 sites of a plasmid DNA, copolymer-mediated triplex stabilization also remarkably competes endonuclease activity of BamH1. Finally, the triplex-stabilizing efficiency of the copolymer is remarkably higher than that of spermine and benzo[e]pyridoindole. Our results indicate that the copolymer, regardless of the length of the target duplex, stabilizes triplexes for significant inhibition of protein-DNA interaction and endonuclease activity. Since stable triplex formation within a short region out of a long native duplex is a prerequisite to confer the therapeutic potential of antigene strategy, triplex stabilization on a long target duplex and inhibition of nuclear protein-DNA interaction may open the possible in vivo applicability of the copolymer.

Design of polymer materials enhancing nucleotide hybridization for anti-gene technology

Stabilization of nucleotide hybridization is considered important for improving gene therapy using oligonucleotides. We have designed comb-type copolymer consisting of polycation backbone (polylysine) and hydrophilic side chains as a stabilizer for double and triple helical DNAs. The copolymer considerably increased the thermal stability of triple helical structure but did not affect the reversible transition between triple helical and single-stranded DNA. An in vitro electrophoretic mobility shift assay revealed that the copolymer remarkably increased association constants of both Hoogsteen and reverse Hoogsteen-type triple helix formation. Moreover the triple helix-stabilizing efficiency of the copolymer was significantly higher than that of other oligocations like spermine and spermidine. Not only being good DNA triple helix stabilizer, it has also been shown to accelerate DNA strand exchange reactions between double helical DNA and its complementary oligonucleotides. From these, we conclude that this copolymer is capable of either 'stabilizing' or 'activating' DNA hybrids, and may useful for gene targeting employing oligonucleotides.

Overexpression of sigma factor, sigma(B), urges Staphylococcus aureus to thicken the cell wall and to resist beta-lactams

Whole genome sequence analysis revealed that Staphylococcus aureus is provided with only a few sigma factors, including the alternative sigma factor, sigma(B), which is thought to regulate some stress responses. Since the sigB knock-out mutant did not show remarkable phenotypic difference, we constructed the over expressed mutant to examine the role of the sigB. Electron microscopic observation revealed that the mutant showed a variety of cell sizes compared with the parent strain which showed almost homogeneous cell sizes. The mutant delivered a thicker cell wall, about 20% thicker than the parent strain. It became resistant to the lytic activity of lysostaphin and also raised MICs to the cell-wall-affecting antibiotics. The yield of carotenoids and transcripts of pbps were also increased in the mutant. The result suggests that sigB plays some important roles in cell wall synthesis and in resistance to antibiotics that perturb the cell wall synthesis.

Clinical value of lung uptake of iodine-123 metaiodobenzylguanidine (MIBG), a myocardial sympathetic nerve imaging agent, in patients with chronic heart failure

This study investigated the clinical value of I-123 MIBG pulmonary accumulation and washout in patients with chronic heart failure (CHF). Nineteen patients with CHF and 15 normal volunteers (NL) were included. The uptake ratio of heart to mediastinum (H/M), that of lung fields to mediastinum (L/M), and washout rate (WR) of the heart and lung fields were calculated in anterior planar images and compared with results of echocardiography and cardiac catheterization. In the CHF group, the lung uptake in delayed images increased and lung WR was decreased, suggesting pulmonary endothelial lesions. Furthermore, there was a negative correlation between right and left lung WR and pulmonary arterial diastolic pressure (PA(D)) and pulmonary arterial systolic pressure (PA(s)) in the CHF group. Since the WR of MIBG reflected PA, it may be used as an index of severity of cardiac dysfunction.

Synthesis and evaluation of alpha-fucosidase inhibitory activity of 5a-carba-alpha-L-fucopyranose and alpha-DL-fucopyranosylamine

5a-Carba-alpha-L-fucopyranose and -alpha-DL-fucopyranosylamine were synthesized in conventional manner starting from 2,3,4-tri-O-acetyl-6-bromo-6-deoxy-5a-carba-beta-D- and -DL-glucopyranosyl bromides, respectively, and assayed for inhibitory activity against alpha-fucosidase (bovine kidney). Although the former proved to be only a moderate inhibitor (Ki = 4.3 x 10(-5) M), the latter could be shown to possess strong inhibitory potential (Ki = 2.3 x 10(-7) M). Diastereoisomeric imino-linked 5a'-carbadisaccharides were synthesized by coupling of the racemic 5a-carba-alpha-fucopyranosylamine and 1,6:3,4-dianhydro-2-azido-2-deoxy-beta-D-galactopyranose, in order to estimate approximately the inhibitory activity of individual optical antipodes of 5a-carba-alpha-fucopyranosylamine.

Loss of motility-related protein 1 (MRP1/CD9) and integrin alpha3 expression in endometrial cancers

BACKGROUND

MRP1/CD9 and integrin alpha3 have played crucial roles in cell adhesion, motility, and signaling events. The loss of MRP1/CD9 and integrin alpha3 has been involved in tumor growth and metastasis of cancer cells. The aim of the current study was to clarify the clinical significance of MRP1/CD9 and integrin alpha3 in endometrial cancer.

METHODS

The expression of MRP1/CD9 and integrin alpha3 from the same tissue sample were examined immunohistochemically in 15 patients with normal endometrium and in 56 patients with uterine endometrioid adenocarcinoma. Disease-free survival curves were estimated using the Kaplan-Meier method and analyzed by the log-rank test between the positive and reduced expression statuses of both MRP1/CD9 and integrin alpha3. These expressions and clinicopathologic variables were analyzed univariately and multivariately.

RESULTS

In normal endometrium, MRP/CD9 was expressed at the cell membrane of cell contact sites, and the expression of integrin alpha3 was detected also at the cell membrane of cell contact sites and at borders of stromal tissues. In patients with endometrioid adenocarcinoma, 17 cases showed reduced expression of MRP1/CD9, and 20 cases had reduced expression of integrin alpha3. Fourteen cases indicated a reduced expression of both MRP1/CD9 and integrin alpha3. Each reduced expression of MRP1/CD9 or integrin alpha3 was significantly correlated with histologic grade and metastasis. Multivariate analysis using the Cox regression model disclosed that age at surgery, metastasis, and expression status of MRP1/CD9 were significant prognostic factors for disease-free survival.

CONCLUSIONS

These findings suggested that the analysis for the expression statuses of MRP1/CD9 and integrin alpha3 may provide important information on the clinical behavior of endometrial cancer.

Beta-cyanoalanine synthase and cysteine synthase from potato: molecular cloning, biochemical characterization, and spatial and hormonal regulation

Beta-cyanoalanine synthase (CAS, L-3-cyanoalanine synthase; EC 4.4.1.9) is the most important enzyme in cyanide metabolism. In addition to CAS, cysteine synthase (CS, EC 4.2.99.8) possesses CAS activity. To explore the physiological significance of cyanide metabolism, we isolated the cDNA clones corresponding to purified CAS (designated PCAS-1 and PCAS-2) and CS (designated PCS-1 and PCS-2) from potato using the information of these amino acid sequences. The recombinant proteins of PCS-1, PCS-2 and PCAS-1 catalyzed both CAS and CS reactions, although the ratios between CAS and CS activity were remarkably different. PCAS-1 preferred the substrates for the CAS reaction to the substrates for the CS reaction. From the kinetic characters and homology of amino acid sequences with known CS-like proteins, PCS-1, PCS-2 and PCAS-1 were identified as cytosolic CS, plastidic CS and mitochondrial CAS, respectively. The highest level of CAS activity, CAS protein and its mRNA were detected in potato buds. Stimulation of CAS activity and protein accumulation by ethylene without the concomitant increase of its mRNA suggested that ethylene induces CAS protein accumulation at the post-transcriptional level.

Clinicopathologic and familial characteristics of endometrial carcinoma with multiple primary carcinomas in relation to the loss of protein expression of MSH2 and MLH1

BACKGROUND

The frequency of synchronous or metachronous multiple primary carcinomas in patients with endometrial carcinoma has been reported to be between 10% and 23% and is highest among all gynecologic carcinomas. However, clinical characteristics and underlying genetic abnormalities in endometrial carcinoma with multiple primary carcinomas has not been well clarified. Endometrial carcinoma is the most commonly associated extracolonic malignancy in hereditary nonpolyposis colorectal carcinoma in which germ line mutations in DNA mismatch repair genes, particularly in MSH2 and MLH1, are known to cause this syndrome. The purpose of the current study was to investigate clinicopathologic and familial characteristics including MSH2, MLH1, and p53 expression in endometrial carcinoma with multiple primary carcinomas, by comparing them to endometrial carcinoma without other primary malignancies.

METHODS

Patients were divided into two groups: 30 patients with synchronous or metachronous multiple primary carcinomas other than endometrial carcinoma and 116 patients with endometrial carcinoma without other primary malignancies. Clinicopathologic characteristics, family history of cancer, and immunohistochemical protein expression of MSH2, MLH1, and p53 expression were investigated in both groups, and 15 endometria from benign disease were used for normal controls in immunohistochemistry.

RESULTS

The frequency of high risk clinicopathologic factors of endometrial carcinoma and 5-year survival rates and the frequency of p53 overexpression were not statistically different between the two groups. However, the loss of MSH2 and/or MLH1 expression was significant in endometrial carcinoma with multiple primary carcinomas, when compared with endometrial carcinoma alone (22 of 30 vs. 31 of 116). In cases with multiple primary carcinomas, particularly those diagnosed before the patient was 55 years of age or those in which the patient had a family history of cancer, the frequency of this loss was especially high (11 of 13 and 10 of 11, respectively).

CONCLUSIONS

The clinical or biologic nature of endometrial carcinoma with multiple primary carcinomas seems to be similar to endometrial carcinoma alone. A high incidence of defective MSH2 and MLH1 protein in endometrial carcinoma with multiple primary carcinomas, however, suggests that abnormalities in the function of MSH2 and MLH1 may play an important role in tumorigenesis for patients with endometrial carcinoma with multiple primary carcinomas and their families.

Whole genome sequencing of meticillin-resistant Staphylococcus aureus

BACKGROUND

Staphylococcus aureus is one of the major causes of community-acquired and hospital-acquired infections. It produces numerous toxins including superantigens that cause unique disease entities such as toxic-shock syndrome and staphylococcal scarlet fever, and has acquired resistance to practically all antibiotics. Whole genome analysis is a necessary step towards future development of countermeasures against this organism.

METHODS

Whole genome sequences of two related S aureus strains (N315 and Mu50) were determined by shot-gun random sequencing. N315 is a meticillin-resistant S aureus (MRSA) strain isolated in 1982, and Mu50 is an MRSA strain with vancomycin resistance isolated in 1997. The open reading frames were identified by use of GAMBLER and GLIMMER programs, and annotation of each was done with a BLAST homology search, motif analysis, and protein localisation prediction.

FINDINGS

The Staphylococcus genome was composed of a complex mixture of genes, many of which seem to have been acquired by lateral gene transfer. Most of the antibiotic resistance genes were carried either by plasmids or by mobile genetic elements including a unique resistance island. Three classes of new pathogenicity islands were identified in the genome: a toxic-shock-syndrome toxin island family, exotoxin islands, and enterotoxin islands. In the latter two pathogenicity islands, clusters of exotoxin and enterotoxin genes were found closely linked with other gene clusters encoding putative pathogenic factors. The analysis also identified 70 candidates for new virulence factors.

INTERPRETATION

The remarkable ability of S aureus to acquire useful genes from various organisms was revealed through the observation of genome complexity and evidence of lateral gene transfer. Repeated duplication of genes encoding superantigens explains why S aureus is capable of infecting humans of diverse genetic backgrounds, eliciting severe immune reactions. Investigation of many newly identified gene products, including the 70 putative virulence factors, will greatly improve our understanding of the biology of staphylococci and the processes of infectious diseases caused by S aureus.

Enhanced effect of sulfonylurea (SU) in copolymer comprising a sugar moiety and SU derivative as double ligands on insulin secretion from MIN6 cells

Copolymers composed of sulfonylurea (SU) as an antagonist of ATP-sensitive K+ channel and sugar moieties as double ligands were synthesized. Insulin secretion from MIN6 cells (insulinoma cell line) in contact with the copolymers was evaluated. MIN6 cells attached to the poly(N-p-vinylbenzyl-D-maltonamide-co-SU) [P(VMA-co-SU)]-coated dishes were in the more aggregated form as compared to other polymer-coated surfaces. By introducing SU into the sugar bearing homopolymer, an enhanced effect on insulin secretion from MIN6 cells was observed due to the specific interaction between SU ligands and SU receptors on the beta-cell membrane. P(VMA-co-SU) composed of SU and non-reducing glucose moieties demonstrated enhanced insulin secretion from MIN6 cells and faster proliferation of MIN6 cells as compared to poly(N-p-vinylbenzyl-D-lactonamide-co-SU) [P(VLA-co-SU)] probably owing to the glucose transporters presence on the MIN6 cell membrane. Insulin secretion from MIN6 cells pretreated with diazoxide as an agonist of ATP-sensitive K+ channel was suppressed.

Persistent infection mechanism of GB virus C/hepatitis G virus differs from that of hepatitis C virus

OBJECTIVE

Changes in the deduced amino acid sequence of the envelope 2 (E2) region of the GB virus C/hepatitis G virus (GBV-C/HGV) were analyzed to investigate whether or not the region contributes to persistent infection with the virus.

METHODS

Eight patients with acute hepatitis C and 1 patient with acute hepatitis of unknown etiology were included in the study. GBV-C/HGV RNA was detected in 6 patients, including the patient with hepatitis of unknown origin. The nucleotide sequence of the E2 region of hepatitis C virus (HCV) and GBV-C/HGV was determined by direct sequencing of polymerase chain reaction products in 5 patients with HCV infection and in 6 patients with GBV-C/HGV infection twice during the period of early infection and several months or years later in each patient.

RESULTS

The mean substitution rate of the deduced amino acid sequence in the E2 region was over 100 times lower (p < 0.001) in GBV-C/HGV (0.01 +/- 0.04/month/100 sites) than in HCV (2.4 +/- 1.7/month/100 sites). The amino acid sequence of the loop domain of GBV-C/HGV-E2 did not change in any of the 6 patients. On the other hand, the sequence of the hypervariable region of HCV-E2 changed remarkably (5.9 +/- 4.3/month/100 sites). No amino acid substitution in the loop domain was observed in 7 additional patients who showed persistent GBV-C/HGV viremia for more than 2 years.

CONCLUSION

These results indicate that changes in the amino acid sequence of the E2 region are not involved in the mechanism of persistent GBV-C/HGV infection.

ATP production from adenine by a self-coupling enzymatic process: high-level accumulation under ammonium-limited conditions

To improve ATP production from adenine, we optimized cultivation and reaction conditions for the ATP producing strain, Corynebacterium ammoniagenes KY13510. In the conventional method, 28% NH4OH has been used both to adjust pH during cultivation and reaction, and to provide nitrogen for cell growth. In the ATP-producing reaction, high concentrations of inorganic phosphate and magnesium ion are needed, which form magnesium ammonium phosphate (MgNH4PO4) precipitate. To keep inorganic phosphate and magnesium ions soluble in the reaction mixture, it was indispensable to add phytic acid as a chelating agent of divalent metal ions. Under such conditions, 37 mg/ml (61.2 mM) ATP was accumulated in 13 h (Appl. Microbiol. Biotechnol. 21, 143 1985). If ammonium ion was depleted from the reaction mixture to avoid MgNH4 PO4 formation, we expected that there was no need to add phytic acid and ATP accumulation might be improved. Therefore, we obtained the cultured broth of C. ammoniagenes KY13510 strain with low ammonium ion content (less than 1 mg/ml as NH3) by the method that a part of alkali solution (28% NH4OH) for pH control was replaced with 10 N KOH. Using this culture broth, ATP producing reaction was done in 2-liter jar fermentor, controlling the pH of the reaction mixture with 10 N KOH. Under these conditions, the rate of ATP accumulation improved greatly, and 70.6 mg/ml (117 mM) ATP was accumulated in 28 h. The molar conversion ratio from adenine to ATP was about 82%. Phytic acid was slightly inhibitory to ATP formation under these ammonium-limited conditions.