Design of an effective small expression tag to enhance GPCR production in E. coli-based cell-free and whole cell expression systems

G protein-coupled receptors (GPCRs) play crucial roles in sensory, immune, and tumor metastasis processes, making them valuable targets for pharmacological and sensing applications in various industries. However, most GPCRs have low production yields in Escherichia coli (E. coli) expression systems. To overcome this limitation, we introduced AT10 tag, an effective fusion tag that could significantly enhance expression levels of various GPCRs in E. coli and its derived cell-free protein synthesis (CFPS) system. This AT10 tag consisted of an A/T-rich gene sequence designed via optimization of translation initiation rate. It is translated into a short peptide sequence of 10 amino acids at the N-terminus of GPCRs. Additionally, effector proteins could be utilized to suppress cytotoxicity caused by membrane protein expression, further boosting GPCR production in E. coli. Enhanced expression of various GPCRs using this AT10 tag is a promising approach for large-scale production of functional GPCRs in E. coli-based CFPS and whole cell systems, enabling their potential utilization across a wide range of industrial applications.

[Analysis of factors influencing lung function in patients with pneumoconiosis]

Objective: To analyze the influencing factors of lung function in pneumoconiosis patients, and to provide reference for clinical treatment. Methods: From July 2020 to December 2020, a questionnaire survey was conducted on pneumoconiosis patients in the jurisdiction by using the "Guangdong Province Occupational Disease Prevention and Control Institute" questionnaire, and the relevant items of patients were examined. The rate of counting data is expressed, and the measurement data is expressed by mean and standard deviation. Chi-square test was used for comparison between groups, trend chi-square test was used for trend analysis of ordered classified data. Multivariate analysis was carried out with binary logistic regression model. Results: A total of 1409 pneumoconiosis patients were enrolled. The abnormal rate of lung function in pneumoconiosis patients was 68.77%. The results of trend Chi-square test showed that the abnormal rate of lung function increased with the age of exposure to dust in different age groups (Chi Sqnare Trend=64.12、8.49、24.20, P<0.05) . In univariate analysis, there were statistical significance in different dust exposure age, working age, pneumoconiosis stage, complications and occupational pneumoconiosis diseases (P<0.05) . Multiple logistic regression results showed that age of exposure to dust, years of service, stage of pneumoconiosis and complications were the main influencing factors of lung function in pneumoconiosis patients (P<0.05) . Compared with patients aged 0-30 years, patients aged 50-70 years and older had a higher rate of abnormal lung function (OR=2.16, 95%CI: 1.12~4.16; OR=4.82, 95%CI: 2.05~11.35, all P<0.05) ; Compared with patients with 0~20 years of service, patients with 20~30 years of service and more than 30 years of service had a higher rate of abnormal lung function (OR=1.58, 95%CI: 1.10~2.25; OR=1.63, 95%CI: 1.28~2.40, P<0.05) ; Compared with stage Ⅰ patients, Stage Ⅱ and Stage Ⅲ patients had a higher rate of abnormal lung function (OR=1.62, 95%CI: 1.20~2.17; OR=2.23, 95%CI: 1.40~3.55, all P<0.05) ; Compared with patients without comorbidities, patients with comorbidities had a higher rate of abnormal lung function (OR=1.68, 95%CI: 1.20~2.38, P<0.05) . Conclusion: The factors such as age of exposure to dust, working age, stage of pneumoconiosis and complications may be the influencing factors of lung function in pneumoconiosis patients.

Programmable synthetic biology tools for developing microbial cell factories

Microbial conversion to generate value-added chemicals from diverse biomass is one of the keystones of energy biotechnology. Programmable synthetic biology tools offer versatile, standardized options for developing microbial cell factories. These tools thus can be reprogrammed in a user-defined manner for flexible wiring of stimuli and response, highly efficient genome engineering, and extensive perturbation of metabolic flux and genetic circuits. They also can be modularly assembled to construct elaborate and unprecedented biological systems with unique features. This review highlights recent advances in programmable synthetic biology tools based on biosensors, CRISPR-Cas, and RNA devices for developing microbial cell factories that have the potential to be utilized for energy biotechnology.

Synthetic biosensor accelerates evolution by rewiring carbon metabolism toward a specific metabolite

Proper carbon flux distribution between cell growth and production of a target compound is important for biochemical production because improper flux reallocation inhibits cell growth, thus adversely affecting production yield. Here, using a synthetic biosensor to couple production of a specific metabolite with cell growth, we spontaneously evolve cells under the selective condition toward the acquisition of genotypes that optimally reallocate cellular resources. Using 3-hydroxypropionic acid (3-HP) production from glycerol in Escherichia coli as a model system, we determine that mutations in the conserved regions of proteins involved in global transcriptional regulation alter the expression of several genes associated with central carbon metabolism. These changes rewire central carbon flux toward the 3-HP production pathway, increasing 3-HP yield and reducing acetate accumulation by alleviating overflow metabolism. Our study provides a perspective on adaptive laboratory evolution (ALE) using synthetic biosensors, thereby supporting future efforts in metabolic pathway optimization.

Synthetic protein quality control to enhance full-length translation in bacteria

Coupled transcription and translation processes in bacteria cause indiscriminate translation of intact and truncated messenger RNAs, inevitably generating nonfunctional polypeptides. Here, we devised a synthetic protein quality control (ProQC) system that enables translation only when both ends of mRNAs are present and followed by circularization based on sequence-specific RNA-RNA hybridization. We demonstrate that the ProQC system dramatically improved the fraction of full-length proteins among all synthesized polypeptides by selectively translating intact mRNA and reducing abortive translation. As a result, full-length protein synthesis increased up to 2.5-fold without changing the transcription or translation efficiency. Furthermore, we applied the ProQC system for 3-hydroxypropionic acid, violacein and lycopene production by ensuring full-length expression of enzymes in biosynthetic pathways, resulting in 1.6- to 2.3-fold greater biochemical production. We believe that our ProQC system can be universally applied to improve not only the quality of recombinant protein production but also efficiencies of metabolic pathways.

Structural maintenance of chromosomes 2 is identified as an oncogene in bladder cancer in vitro and in vivo

Taurine upregulated gene 1 (TUG1) has been found to promote bladder cancer cell growth in our recent research. In this study, TUG1-depleted bladder cancer cells were used to identify potent players in bladder cancer. Human gene expression arrays were used for transcriptome profiling of TUG1-depleted bladder cancer cells. Cell proliferation was analyzed by MTT assay. Cell apoptosis and cell cycle were analyzed by flow cytometry. Colony formation assay was used to observe the changes of colony formation rates. Xenograft formation assay was performed in nude mice. Immunohistochemical staining was used to test the gene expression levels in tissues from bladder cancer patients. We found that deregulated genes were strongly enriched in cell cycle or pathways in cancer in TUG1-depleted bladder cancer cells. Structural maintenance of chromosomes 2 (SMC2) was inhibited after TUG1 knockdown. The depletion of TUG1 or SMC2 led to G2/M phase arrest in bladder cancer cells. SMC2 depletion inhibited bladder cancer cell proliferation, promoted apoptosis, decreased colony formation, and reduced tumor growth in xenograft nude mice. Overexpression of SMC2 restored the growth of TUG1-depleted cells. The expression levels of SMC2 were higher in human bladder cancer tissues than that in paired normal tissues. Our data suggest that SMC2 is an oncogene in bladder cancer and depletion of SMC2 might have potential therapeutical significance in bladder cancer.

Stem cell therapy in pain medicine

Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.

Spatiotemporal microstructural white matter changes in diffusion tensor imaging after transient focal ischemic stroke in rats

Structural reorganization in white matter (WM) after stroke is a potential contributor to substitute or to newly establish the functional field on the injured brain in nature. Diffusion tensor imaging (DTI) is an imaging modality that can be used to evaluate damage and recovery within the brain. This method of imaging allows for in vivo assessment of the restricted movements of water molecules in WM and provides a detailed look at structural connectivity in the brain. For longitudinal DTI studies after a stroke, the conventional region of interest method and voxel-based analysis are highly dependent on the user-hypothesis and parameter settings for implementation. In contrast, tract-based spatial statistics (TBSS) allows for reliable voxel-wise analysis via the projection of diffusion-derived parameters onto an alignment-invariant WM skeleton. In this study, spatiotemporal WM changes were examined with DTI-derived parameters (fractional anisotropy, FA; mean diffusivity, MD; axial diffusivity, DA; radial diffusivity, RD) using TBSS 2 h to 6 weeks after experimental focal ischemic stroke in rats (N = 6). FA values remained unchanged 2-4 h after the stroke, followed by a continuous decrease in the ipsilesional hemisphere from 24 h to 2 weeks post-stroke and gradual recovery from the ipsilesional corpus callosum to the external capsule until 6 weeks post-stroke. In particular, the fibers in these areas were extended toward the striatum of the ischemic boundary region at 6 weeks on tractography. The alterations of the other parameters in the ipsilesional hemisphere showed patterns of a decrease at the early stage, a subsequent pseudo-normalization of MD and DA, a rapid reduction of RD, and a progressive increase in MD, DA and RD with a decreased extent in the injured area at later stages. The findings of this study may reflect the ongoing processes on tissue damage and spontaneous recovery after stroke.

Difficulties and practices regarding information provision among Korean and Italian nurses

AIM

To investigate nurses' opinions and practices of providing information in a global context through cultural comparison.

BACKGROUND AND INTRODUCTION

Providing sufficient information to patients about nursing interventions and plans is essential for patient-centred care. While many countries have specific legislation making information delivery to patients a legal duty of nurses, no such legislation exists in both the Republic of Korea and Italy; nurses' only guidance is the deontological code.

METHODS

This was a cross-sectional survey study involving a convenience sample of 174 Korean nurses and 121 Italian nurses working in internal medicine and surgery at university hospitals. Data were collected using a self-administered questionnaire between February and November 2014. The questionnaire assessed demographic and professional characteristics, and difficulties and practices regarding information provision.

RESULTS

Korean and Italian nurses significantly differed in all demographic and professional characteristics. More Korean than Italian participants reported that their role in providing information was well explained within their teams, but both groups reported the same level and type of difficulties in delivering information. Nurses in both countries regularly informed patients about medications and nursing procedures, but provided information about nursing care plans less frequently. Few nurses frequently provided information to relatives instead of patients.

CONCLUSIONS

Despite cultural, demographic and professional differences between Korean and Italian nurses, their difficulties and practices in information delivery to patient were similar.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

Hospital managers and policymakers should be aware that nurse-patient communication can be impaired by organizational factors, patient characteristics or the interaction among providers. Educational interventions and strategies are needed to increase information provision to patients about nursing care plans.

[Research progress of mutational spectrum and pathophysiology of WFS1 gene in Wolfram syndrome and nonsyndromic low frequency sensorineural hearing loss]

Compound homozygous or heterozygous mutations in WFS1 can lead to autosomal recessive Wolfram syndrome (WS), and heterozygous mutations in WFS1 can lead to autosomal dominant non-syndromic low frequency sensorineural hearing loss (LFSNHL). In addition, mutations in the WFS region has relationship with diabetes and psychiatric diseases. In this paper, we provide an overview of genetic research with different phenotypes, including WS and LFSNHL.

[Finite element analysis of different load mode on tooth movement for space closure in patient with bimaxillary protrusion]

OBJECTIVE

To investigate the stress distribution on the maxillary anterior teeth retracted with sliding mechanics and micro-implant anchorage using different retraction hook heights and positions.

METHODS

DICOM image data including maxilla and upper teeth were obtained with cone-beam CT. The three-dimensional finite element model was constructed using Mimics software. Brackets and archwire model were constructed using Creo software. The models were instantiated using Pro/Engineer software. Abaqus software was used to simulate the sliding mechanics by loading 2 N force on 0, 2, 4, 6, 8, 10 mm retraction hooks and three different positions, repectively. Rotation of the occlusal plane, the initial displacement and stress distribution of teeth were analyzed.

RESULTS

Lingual rotation of maxillary central incisor(0.021°), gingival movement of the maxillary first molar(0.005 mm), and clockwise rotation of the maxillary occlusal plane(0.012°) were observed when the force application point located at the archwire level (0 mm). In contrast, 0.235° labial rotation of the maxillary central incisor, 0.015 mm occlusal movement of the maxillary first molar, and 0.075° anti-clockwise rotation of the maxillary occlusal plane were observed when the force application point located at the higher level(10 mm retraction hook). The more the force application point was located posteriorly at the archwire level, the less lingual rotation of the maxillary central incisor and the more buccal displacement of maxillary first molar was observed.

CONCLUSIONS

Maxillary anterior tooth rotation and retraction, vertical displacement of posterior segment, and rotation of the occlusal plane could be controlled by adjusting the height and position of the retraction hook in space closure using miniscrew and sliding mechanics.

Proteomic research on diapause-related proteins in the female ladybird, Coccinella septempunctata L

In the experiments reported here, we used the female ladybird Coccinella septempunctata L. as a model to identify diapause-associated proteins using proteomics technology. Our results indicated that protein expression patterns of diapausing and nondiapausing individuals were highly differentiated. A total of 58 spots showed significant differences in abundance (Ratio > 2 and P < 0.05) according to two-dimensional electrophoresis and GE Image Scanner III analysis. Sixteen protein spots were further investigated using mass spectrometry. Eight proteins were characterized, including chaperones and proteins involved in glucose metabolism, lipid metabolism, and the tricarboxylic acid cycle. Among these proteins, five proteins were upregulated in diapausing female adults, including a chaperone (Symbionin symL), malate dehydrogenase (putative), two proteins linked to lipid metabolism (unknown and conserved hypothetical protein) and phosphoglyceromutase (partial). By contrast, isocitrate dehydrogenase (RH49423p), fumarylacetoacetate hydrolase (AGAP001942-PA), and a putative medium chain acyl-CoA dehydrogenase were downregulated. These results contribute to the understanding of diapause mechanisms of the ladybird C. septempunctata and may suggest methods for improving the application of this natural enemy insect.

Association between IL6 polymorphism and risk of cerebral infarction

We conducted a case-control study to investigate the influence of IL6 -174G/C (rs1800795) and -572C/G (rs1800796) genetic variants on the development of cerebral thrombosis in a Chinese population. This study included 305 cerebral infarction patients and 326 control subjects enrolled between May 2012 and May 2014. The genotyping of IL6 -174G/C (rs1800795) and -572C/G (rs1800796) polymorphisms was performed using polymerase chain reaction combined with restriction fragment length polymorphism analysis. By using logistic regression, we found that when compared with the wild-type genotype, CC and GC+CC IL6 -174G/C (rs1800795) genotypes were associated with an increased risk of cerebral infarction. Odds ratios (and 95% confidence intervals) were calculated to be 3.10 (1.57-6.41) and 1.63 (1.14-2.33) for the CC and GC+CC genotypes, respectively. In conclusion, our study suggests that the CC genotype and C allele of the IL6 -174G/C (rs1800795) polymorphism are associated with an increased risk of cerebral infarction.

Cortical Morphology in Patients with Orthostatic Intolerance

BACKGROUND

We evaluated the cortical morphology in patients with orthostatic intolerance.

METHODS

Thirty patients with orthostatic intolerance, as well as age- and sex-matched normal controls, were enrolled in this study. We divided the patients into orthostatic hypotension (n = 22) and postural tachycardia syndrome (n = 8) groups based on their response to a head-up tilt table test. We analyzed whole-brain T1-weighted MRI images using FreeSurfer 5.1. The measures of cortical morphology were compared between the groups.

RESULTS

The cortical thickness in the right hemisphere, including the medial orbitofrontal, peri-calcarine, post-central, inferior temporal, and lateral occipital cortex, and in the peri-calcarine cortex of the left hemisphere was thinned in patients with orthostatic hypotension compared to normal controls. The other measures of cortical morphology, including the surface area, volume, and curvatures, did not differ between patients with orthostatic hypotension and normal controls. However, none of the measures of cortical morphology differed between patients with postural tachycardia syndrome and normal controls.

CONCLUSIONS

We demonstrated that the cortical morphology significantly changed in patients with orthostatic hypotension but not in patients with postural tachycardia syndrome compared to normal controls. These findings support the hypothesis that orthostatic intolerance is a heterogeneous syndrome.

First Report of Wilt of Eucalyptus Caused by Ceratocystis fimbriata in China

Eucalyptus spp., most of which are native to Australia, are one of the world's most commonly planted forestry crops, and have been widely planted in the tropics and subtropics. Eucalyptus trees are distributed in more than 600 counties in 19 provinces/regions throughout China, especially in the southern regions of the country (1). From April of 2013 to May of 2014, eucalyptus trees were noted to be wilting and dying rapidly in Kunming, Yunnan Province (25°02' N, 102°42' E), southwest China. Symptomatic trees typically have many wilted or dead leaves hanging throughout the tree or on some major branches, sometimes followed by death of the whole tree. Dark brown to black discoloration can be seen in the woody xylem, and elongated cankers were also present on some affected trees. A fungus was consistently isolated from the leaves and cankers when symptomatic tissue was incubated between two slices of fresh carrot root. Spore masses were removed from the apices of perithecia, transferred to malt extract agar medium (MEA), and incubated at 25°C. Perithecia developed on the medium, and were black, globose, 212.5 to 242.4 × 207.5 to 254.2 μm, and possessed a long black neck (952.3 to 1,303.3 μm). Ascospores had the typical "hat" morphology and were 4.3 to 5.2 × 3.0 to 3.8 μm. Cylindrical endoconidia (11.2 to 22.2 × 3.9 to 6.1 μm) were found. Chlamydospores produced on media were ovoid and smooth, and were 7.8 to 9.7 × 9.9 to 12.8 μm. Chains of barrel-shaped conidia were not found. PCR amplification and sequencing of the ITS region of rDNA were carried out for one isolate, E2-2, using the procedures of Thorpe et al. (3). Analysis of ITS sequence data (GenBank Accession No. KJ511481) showed that the isolates were 99% homologous to the isolate of C. fimbriata from diseased Colocasia esculenta in Cuba, China, and Hawaii (AY526304 to 06) by BLAST analysis. Thus, the fungus was identified as C. fimbriata based on morphological and molecular characteristics. Pathogenicity tests were made on 1-year-old E. grandis seedlings as follows. A conidial suspension of each isolate was diluted to 10⁶ conidia/ml, and 0.2 ml was injected into wounds on three petioles on each of five healthy plants of E. grandis, and control seedlings were injected with sterile water that had been placed on MEA plates. The seedlings were incubated at 25°C in moist chambers. After 3 days, all inoculated E. grandis plants showed dark brown to black discoloration in the leaf axils. After 5 days, leaf wilting was present. C. fimbriata was re-isolated from all inoculated symptomatic tissue. No symptoms were visible in the control plants and no fungus was isolated from them. Ceratocystis wilt was first observed in eucalyptus in 1997 in the state of Bahia. This was followed by a report of C. fimbriata causing wilt of E. grandis in the Republic of Congo, Uganda, and Uruguay (2). Chen et al. reported two species of Ceratocystis, C. acaciivora and a previously undescribed species C. chinaeucensis, from eucalyptus plantations in Guangdong Province in China (1). To our knowledge, this is the first report of C. fimbriata causing wilt of eucalyptus in China. References: (1) S. F. Chen et al. Fungal Diversity 58:267, 2011. (2) F. A. Ferreira et al. Fitopatol. Bras. 24:284, 1999. (3) D. J. Thorpe et al. Phytopathology 95:316, 2005.

First Report of Ceratocystis fimbriata-Caused Wilt of Eriobotrya japonica in China

The loquat (Eriobotrya japonica (Thunb.) Lindl.), an important perennial evergreen fruit crop that originated in China and is also cultivated as an ornamental plant, is well known all over the world for high nutritional, medicinal, economic, and ecological values (4). So far, it has been grown in more than 30 countries (1) and is becoming an important industry in China, Spain, Japan, India, Pakistan, and Turkey (2). During an investigation from May to August of 2013, severely withered loquat plants were observed in Kunming city of Yunnan Province (25°02' N; 102°42' E), Southwest China. Initial symptoms were brown lesions of leaves and canker on one to several branches, leaves of the whole tree turned wilted. Cross sections of diseased plants revealed irregularly shaped brown discoloration in the xylem of the trunk. A fungus was consistently isolated from the leaf when diseased leaves were incubated between two slices of fresh carrot root. Spore masses were picked from the apices of perithecia and transferred to malt extract agar medium (MEA) and incubated at 25°C. After perithecium formation, observed perithecia were black, globose (176.0 to 303.2 × 186.0 to 274.3 μm) and showed a long black neck (634.2 to 809.9 μm). Ascospore had the typical format of a "hat" with dimensions of 4.6 to 6.3 × 3.3 to 4.8 μm. Cylindrical endoconidia (7.1 to 36.1 × 2.9 to 6.0 μm) were found. Chlamydospores were ovoid or obpyriform and smooth (8.6 to 12.1 × 6.9 to 12.1 μm). PCR amplification was carried out for one isolate, YT2. The ITS region of rDNA was sequenced using the procedures of Thorpe et al (3). Analysis of ITS sequence data (GenBank Accession Nos. KF963101 and KF963102) showed that the isolates were 99% homologous to the isolate of Ceratocystis fimbriata from diseased Colocasia esculenta in Cuba, China, and Hawaii (AY526304 to 06) by BLAST analysis. Therefore, the fungus was identified as C. fimbriata based on morphological and molecular characteristics. Pathogenicity of the six isolates from this study was tested by inoculation of 1-year-old pot grown seedlings of loquat. The soil of six plants was inoculated by drenching with 40 ml spore suspension (10⁶ spores/ml). Control plants were inoculated with 40 ml of sterile distilled water. The plants were maintained in a controlled greenhouse at 25°C and watered weekly. After inoculation for 1 week, all plants produced wilt symptoms; as the disease progressed, leaves withered and died after 3 weeks of inoculation while control plants remained symptomless. C. fimbriata was successfully re-isolated from the infected trees and no fungal growth was observed in the controls. The pathogenicity assay showed that C. fimbriata was pathogenic to loquat. To our knowledge, this is the first report of C. fimbriata causing wilt of loquat in China. Since C. fimbriata is one of the most aggressive plant pathogens on a wide variety of perennial as well as agronomic crop plants worldwide, and the infection can pose a significant threat to the production of loquat, it is critical to deploy appropriate management strategies to limit the fungus spread. References: (1) J. J. Feng et al. Acta Hort. 750:117, 2007. (2) J. Janick. Acta Hort. 750:27, 2007. (3) D. J. Thorpe et al. Phytopathology 95:316, 2005. (4) J. Yan et al. Pak. J. Bot. 44:1215, 2012.

Pressure induced ionic-superionic transition in silver iodide at ambient temperature

Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω(-1)cm(-1) could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag(+) ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ∼3.4 × 10(-4)-8.6 × 10(-4) cm(2)/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III'. By analyzing the half infinite length Warburg diffusion process, two parameters α and β, which closely relate to the disordered state of Ag(+) ions, have been determined and it was suggested that Ag(+) ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω(-1)cm(-1). Evidence for all three, the diffusion coefficient, α and β, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.

Dexamethasone inhibits the effect of paclitaxel on human ovarian carcinoma xenografts in nude mice

BACKGROUND

Recent studies showed that dexamethasone (DEX) could render cancer cells resistant to paclitaxel (PTX) induced apoptosis though an unknown mechanism.

AIM

This study aimed to evaluate the influence of DEX pretreatment on the anti-tumor effect of PTX in an in vivo xenograft model with grafted ovarian cancer SKOV-3 cells innude mice.

MATERIALS AND METHODS

The xenograft procedure was performed, and the nude mice were grouped into four cohorts of ten that received the following treatments: Control group, DEX group, PTX group and DEX+PTX group. Individual treatments were administered once every three days for a total of 6 courses. The growth of tumors and the inhibition rates were measured. Changes in tissue morphology and cellular ultrastructure were observed using light and transmission electron microscopy. Immunohistochemistry was performed to examine the expression of Ki-67, Bcl-xL and cleaved caspase-3.

RESULTS

Premedication with DEX reduced the inhibitory effect of PTX on tumor growth by approximately 20% compared to the PTX-only-treated group in the ovarian carcinoma xeno-grafted mice. Hematoxylin-eosin (H&E) staining revealed that significantly fewer cells exhibited vacuolization and apoptosis in the DEX + PTX group compared to the PTX group. Apoptotic characteristics including karyopyknosis, nuclear chromatin condensation along the nuclear membrane and aggregation were observed in both DEX+PTX and PTX groups under electron microscopy. However, these characteristics were less significant in the DEX+PTX group than those in the PTX group. The immunohistochemistry demonstrated that protein expression levels of Ki-67 and Bcl-xL were significantly increased, whereas cleaved caspase-3 decreased in the DEX+PTX group, compared to PTX group (p < 0.0125).

CONCLUSIONS

DEX inhibits the therapeutic efficacy of PTX in a human ovarian carcinoma SKOV-3 xenograft model.

Identification of a locus characteristic of male individuals of buffalo grass [Buchloe dactyloides (Nutt.) Engelm.] by using an RAPD marker

Buffalo grass [Buchloe dactyloides (Nutt.) Engelm.] plants can be either male, female, or hermaphrodite (monoecious). As there is no morphological difference in the early vegetative growth of these three classes of plants, it is worthwhile to use molecular biological methods to attempt to identify the sex of a plant at this early growth period. In this study, we identified 23 plants that had a stable sex for over at least 3 years. Of these, 9 were male plants, 10 were female plants, and 4 were hermaphrodites. Screening of 300 RAPD primers identified a primer, namely S211 (5'-ttccccgcga-3'), which is capable of identifying male plants. The specific fragment was cloned, sequenced, and submitted to the GenBank database (accession No. JN982469). When used to identify the sex of 188 plants during their first growing season, the S211 primer correctly identified 85.8% of all male plants. Our results showed that the S211 primer can identify the male, and in doing so, it facilitates buffalo grass breeding work.

Down-regulation of TCF21 is associated with poor survival in clear cell renal cell carcinoma

Transcription factor 21 (TCF21) has been identified as a candidate tumor suppressor at 6q23-q24 that is epigenetically inactivated in many types of human cancers. We recently found that TCF21 methylation level was significantly increased in clear cell renal cell carcinoma (ccRCC). The purpose of this study was to investigate the prognostic impact of TCF21 expression in ccRCC and analyze the relationship between TCF21 expression and methylation level. We used real-time PCR and immunohistochemical staining to detect the expression of TCF21, and used methylation specific-PCR (MS-PCR) to determine the methylation status of TCF21 in ccRCC samples and cell line 786-O. The results showed that TCF21 expression level in ccRCC samples was significantly lower than in normal adjacent tissue samples (NAT samples). The Kaplan-Meier survival analysis demonstrated that TCF21 was a significant prognosticator of cancer-specific survival (p=0.001). Furthermore, the DNA demethylating agent 5'-azacytidine restored part of TCF21 expression by suppressing TCF21 methylation in 786-O. The methylation level of TCF21 in ccRCC samples was much higher than in NAT samples. These results suggest that the expression of TCF21 was an independent prognostic factor for poor survival in patients with ccRCC. Aberrant methylation was an important reason for the down-regulation the expression of TCF21, and may be associated with tumorigenesis in ccRCC.

Radiosurgery for metastatic spinal tumors: follow-up MR findings

BACKGROUND AND PURPOSE

MR imaging is the primary tool for evaluation and monitoring of spinal tumors. We retrospectively analyzed the MR imaging findings before and after SRS for metastatic spinal tumors.

MATERIALS AND METHODS

We reviewed MR imaging findings on 79 metastatic spinal tumor lesions in 44 patients (29 male and 15 female)who had undergone radiosurgery between November 2003 and April 2008. Posttreatment MR imaging was evaluated retrospectively for 3 aspects: 1) changes in tumor volume; 2) changes in T2 signal intensity;and 3) changes in contrast enhancement patterns.

RESULTS

With regard to tumor volume on MR images, 32 lesions(40.5%) decreased in volume (group 1), 39 (49.4%) showed no change (group 2), and 8 (10.1%) increased in volume (group 3). T2 signal intensities were unchanged in 4 lesions (type 1), homogeneously increased in 3 (type 2), and changed to a homogeneously dark signal in 4 (type 4). The T2 signal intensity was increased and inter mixed with dark signal intensity (type 3) in 68 lesions. A decrease in contrast enhancement with or without non-enhancing foci was seen in 73 lesions. A persistent homogeneous enhancement pattern was seen in all 4 of the type 1 lesions, in 1 of the 3 type 2 lesions, and in 1 of the 68 type 3 lesions.

CONCLUSIONS

Main MR imaging features of locally controlled metastatic spinal tumors included no increase in tumor volume, increased T2 signal intensity with intermixed T2 dark signal intensity,and decreased contrast enhancement. Follow-up MR imaging also provided several patterns of tumor recurrence [corrected].

Percutaneous insertion of Zilver stent in malignant biliary obstruction

BACKGROUND

We evaluated the clinical efficacy and technical feasibility of the percutaneously inserted self-expandable nitinol stent (Zilver stent) for palliation of malignant biliary obstruction.

METHODS

Seventeen patients with malignant tumors involving the intra- or extrahepatic bile duct who presented with obstructive jaundice underwent percutaneous insertion of a self-expandable nitinol stent. We retrospectively reviewed the hospital records of patients and evaluated the technical feasibility on stent placement, complications, patient survival, and duration of stent patency.

RESULTS

Percutaneous biliary stenting with 27 Zilver stents was performed in 17 patients with malignant biliary obstruction. Technical success was 95%. Malposition of the stent was encountered in one patient. Minor technical problems were encountered in two patients: the introducer tip was broken during stent insertion, so endoscopic removal was done. Mean follow-up period for the 17 patients was 182 days (range 29-485 days): nine patients died of progressive disease at a mean follow-up of 151 days (range 61-371days) after stent insertion and eight patients remained alive at the final follow-up of 216 days (range 29-485 days). The median survival period for all patients was 277 days. The stent occlusion rate was 26% and the mean patency period was 280 days. In five patients, seven stents were obstructed by tumor ingrowth and overgrowth. Stent patency rates were 100%, 100%, 75%, 61%, and 41% at 1, 2, 3, 6, and 12 months, respectively. A late complication, erosive bleeding of the hepatic artery by the stent, developed in one patient.

CONCLUSION

Percutaneous biliary stenting using the nitinol stent is technically feasible and safe and clinically efficacious treatment for malignant biliary obstruction, even with a minor technical problem during stent insertion.

Correlation analysis among highway stormwater pollutants and characteristics

Stormwater runoff from highway land use is a common non-point source of pollutants. A large quantity of highway stormwater runoff characteristics were collected in California during the past three years. Correlations among various water quality parameters and constituents were performed using data sets collected over the 2000-2001, 2001-2002, and 2002-2003 wet seasons for 18, 21 and 23 storm events at three highway sites in west Los Angeles, California. In addition, statistical and graphical correlation analysis of the mass first flush ratio (MFF) with storm characteristics was made to determine if the first flush is related to site or storm characteristics. The results and analyses performed indicate that (1) TSS correlates well with most particulate-bound metals. However, TSS was poorly correlated with most other pollutants. (2) Strong correlations were also observed among dissolved and total metals; DOC, COD, TKN and oil and grease; conductivity and Cl. (3) Total metals, COD and DOC were generally well correlated with mass first flush, suggesting that BMPs that treat the early portion of runoff have an opportunity to remove high concentrations of these pollutants.

Neuro-ophthalmology of late-onset Tay-Sachs disease (LOTS)

BACKGROUND

Late-onset Tay-Sachs disease (LOTS) is an adult-onset, autosomal recessive, progressive variant of GM2 gangliosidosis, characterized by involvement of the cerebellum and anterior horn cells.

OBJECTIVE

To determine the range of visual and ocular motor abnormalities in LOTS, as a prelude to evaluating the effectiveness of novel therapies.

METHODS

Fourteen patients with biochemically confirmed LOTS (8 men; age range 24 to 53 years; disease duration 5 to 30 years) and 10 age-matched control subjects were studied. Snellen visual acuity, contrast sensitivity, color vision, stereopsis, and visual fields were measured, and optic fundi were photographed. Horizontal and vertical eye movements (search coil) were recorded, and saccades, pursuit, vestibulo-ocular reflex (VOR), vergence, and optokinetic (OK) responses were measured.

RESULTS

All patients showed normal visual functions and optic fundi. The main eye movement abnormality concerned saccades, which were "multistep," consisting of a series of small saccades and larger movements that showed transient decelerations. Larger saccades ended earlier and more abruptly (greater peak deceleration) in LOTS patients than in control subjects; these changes can be attributed to premature termination of the saccadic pulse. Smooth-pursuit and slow-phase OK gains were reduced, but VOR, vergence, and gaze holding were normal.

CONCLUSIONS

Patients with late-onset Tay-Sachs disease (LOTS) show characteristic abnormalities of saccades but normal afferent visual systems. Hypometria, transient decelerations, and premature termination of saccades suggest disruption of a "latch circuit" that normally inhibits pontine omnipause neurons, permitting burst neurons to discharge until the eye movement is completed. These measurable abnormalities of saccades provide a means to evaluate the effects of novel treatments for LOTS.

Stereoselective metabolism of silybin diastereoisomers in the glucuronidation process

A separation method for the hepatoprotective drug silybin and its metabolites by RP-HPLC was described. Based on this separation, the stereoselectivity of the metabolism of silybin was investigated by incubation of the drug and its two diastereoisomers with bovine liver microsomes. Information about the structures of these metabolites was obtained, using UV, HPLC/MS and NMR spectra. Four major metabolites (M(1), M(4) of silybin A and M(2), M(5) of silybin B), were prepared by preparative HPLC, and their configurations were accomplished by NMR spectra. A HPLC method was used to quantify the metabolites. The results showed that silybin was extensively metabolized and the major sites for glucuronidation were the C-20, C-7, at phenolic OH groups. Furthermore, the results obtained reveal that there was significant stereoselectivity in the glucuronidation process of silybin. Silybin B was glucuronidated at a more efficient rate than its diastereoisomer, and glucuronidation of silybin B was much preferred at the 20 position, while that of silybin A was similar at both 7 and 20 position.

Folate intake estimated with an updated database and its association to blood folate and homocysteine in Korean college students

OBJECTIVE

To measure folate content in cooked foods commonly consumed in Korea for evaluating its relation to folate nutriture of college students.

DESIGN

Folate content in 32 raw and cooked foods was measured by microbiological assay after trienzyme extraction. These values and the previously published values of 110 raw foods commonly consumed in Korea were used to update the currently available food tables to estimate dietary folate intake of 106 students based on a 3-day 24-h recall. The association of folate intake with blood folate and homocysteine concentrations was evaluated.

SETTING

Cheongju, Korea.

SUBJECTS

Healthy college students aged 18 to 27 y old (44 males and 62 females).

RESULTS

The average folate loss in 32 foods caused by cooking was 29%. The mean daily dietary folate intakes estimated with an updated database were 406 and 305 mug in males and females, respectively. About 10% of both male and female students showed low serum folate (<6.8 nmol/l). Folate intake was positively correlated with serum and erythrocyte folate concentrations in female students (r=0.27 and 0.29, respectively, P<0.05), and negatively correlated with serum homocysteine in male students (r=-0.41, P<0.05).

CONCLUSIONS

Mean dietary folate intake was higher than those of previous studies since the database was updated using values obtained with trienzyme extraction. Folate intake for the general population should be re-evaluated using reliable food folate values obtained with trienzyme extraction.

A kinetic study of enhancing effect by phenolic compounds on the hydroxyl radical generation during ozonation

Ozone decomposition in aqueous solution proceeds through a radical type chain mechanism. These reactions involve the very reactive and catalytic intermediates O2- radical, OH radical, HO2 radical, OH-, H2O2, etc. OH radical is proposed as an important factor in the ozonation of water among them. In the present study, the enhancing effects of several phenolic compounds; phenol, 2-, 3-, 4-monochloro, 2,4-dichloro, 2,4,6-trichlorophenol on OH radical generation were mathematically evaluated using the electron spin resonance (ESR)/spin-trapping technique. OH radical was trapped with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The initial velocities of DMPO-OH generation in ozonated water containing phenolic compounds were quantitatively measured using a combined system of ESR spectroscopy with stopped-flow apparatus, which was controlled by homemade software. The initial velocities of DMPO-OH generation increased as a function of the ozone concentration. The relation among ozone concentration, amount of phenolic compounds and the initial velocity (v0) of DMPO-OH generation was mathematically analyzed and the following equation was obtained, v0 (10(-6) M/s) = (A' x [PhOHs (10(-9) M)] + 0.0005) exp (60 x [ozone (10(-9) M)]). The equation fitted very well with the experimental results, and the correlation coefficient was larger than 0.98.

Association study of neuregulin 1 gene with schizophrenia

A number of studies have indicated that 8p22-p12 is likely to harbor schizophrenia susceptibility loci. In this region, the candidate gene of interest, neuregulin 1 (NRG1), may play a role in the pathogenesis of schizophrenia. Then in the present study, we performed the linkage disequilibrium to determine the association between three genetic variants (SNPs: rs3924999, rs2954041, SNP8NRG221533) on NRG1 gene and schizophrenia in 246 Chinese Han schizophrenic family trios using PCR-based restriction fragment length polymorphism method and denaturing high-performance liquid chromatography. The transmission disequilibrium test analysis for each variant showed a significant difference between two transmitted alleles even after Bonferroni correction (rs3924999, P=0.007752; rs2954041, P=0.0009309; SNP8NRG221533, P=0.012606). The global chi(2) test for haplotype transmission also revealed a strong association (chi(2)=46.068, df=7, P&<0.000001). Our results suggest that the NRG1 gene may play a role in conferring susceptibility to the disease.

Physical mapping of the 5S and 45S rDNA in teosintes

The physical locations of the 5S and 45S rDNA sequences were examined in three types of teosinte, Zea mays ssp. mexicana (2n = 20), Zea diploperennis (2n = 20) and Zea perennis (2n = 40) by biotinylated fluorescence in situ hybridization (FISH). The tested materials only showed one hybridization site of 5S rDNA on their genomes, but they were different in the position of the signals. The hybridization site of Zea mays ssp. mexicana was located on the long arm of chromosome 2, indicating that it is the same as the cultivated maize in the position of 5S rDNA, while the sites of Zea diploperennis and Zea perennis were on the short arms of other chromosomes. For 45S rDNA, one hybridization site was detected at secondary constriction region of the satellite chromosomes in Zea mays ssp. mexicana and Zea diploperennis, while in Zea perennis, besides the site located at the secondary constriction region, a second site on the short arm of another chromosome pair was observed. Our results provide additional evidence for Zea mays ssp. mexicana being a subspecies of Zea mays.

Stability of exploratory eye movements as a marker of schizophrenia--a WHO multi-center study. World Health Organization

The exploratory eye movements of patients with schizophrenia reportedly differ from those of patients without schizophrenia and healthy controls. In an attempt to determine whether exploratory eye movements provide valid markers for schizophrenia, the present collaborative study was conducted in six countries to analyze the stability of and variation in the following parameters of exploratory eye movements: the number of eye fixations (NEFs) and mean eye scanning length (MESL) in a retention task; the cognitive search score (CSS) that indicates how frequently the eye focused on each important area of a figure in order to recognize it in a comparison task; and the responsive search score (RSS), which reflects the frequency of eye fixations on each section of a figure in response to questioning in a comparison task. In addition, we investigated the validity of the currently employed discriminant function to extract a common feature of schizophrenia by applying it to the findings of the present study. The exploratory eye movements of 145 patients with schizophrenia, 116 depressed patients and 124 healthy controls at seven WHO collaborative centers in six countries were measured using eye mark recorders during viewing of stationary S-shaped figures in two sequential tasks. The RSSs of patients with schizophrenia were found to be significantly lower than those of depressed patients or healthy controls irrespective of geographical location, with no significant difference existing between the RSSs for depressed patients and those for healthy controls. By inserting the RSS and NEF data for each subject into the formula used to calculate discriminant function, patients with schizophrenia could be discriminated from depressed patients and healthy controls with a sensitivity of 89.0% and a specificity of 86.7%. The RSS is an exploratory eye movement parameter that detected schizophrenia irrespective of culture, race and various other subject variables. Furthermore, it is indicative of the stable, significant difference that exists between subjects with and without schizophrenia. The results of discriminant analysis confirm the previously reported validity of discriminant function.

New strategy for the cultivation of microalgae using microencapsulation

The four species of microalgae (Dunaliella bardawil, Chlorella minutissima, Pavlova lutheri and Haematococcus pluvialis) were immobilized in Ca-alginate capsules as a basic study for the development of the economic cultivation process. Under the batch culture of aerobic conditions, the thickness of the capsule membrane and CO2 supply did not affect the growth of the immobilized microalgae, Dunaliella bardawil. Cell concentration of immobilized microalgae in the capsule was higher than those of immobilized microalgae in beads and free cells. The cell concentrations of microencapsulated Dunaliella bardawil and Haematococcus pluvialis were five times greater than that of free cells. Based on these results, microencapsulation for the culture of microalgae was an effective method for the high-density cultivation. In comparison to the immobilized cultivation on the bioreactor type, it was more effective for the cultivation in the bubble column bioreactor than that in the stirrer tank bioreactor.

Malignant obstruction of gastric outlet and duodenum: palliation with flexible covered metallic stents

PURPOSE

To assess the usefulness of flexible covered metallic stents in the palliation of malignant obstruction of the gastric outlet and duodenum.

MATERIALS AND METHODS

Twenty-four consecutive patients with malignant obstruction of the gastric outlet (n = 22) or duodenum (n = 2) underwent palliative treatment with self-expandable flexible covered metallic stents. Fourteen patients had advanced gastric carcinoma at the antrum and/or pylorus, and eight had obstruction at the anastomosis site of previous gastrojejunostomy. Complications and clinical status were investigated during the study period.

RESULTS

The technical success rate was 75% (18 of 24 patients). Twenty-one stents were placed in 18 patients by using an introducer 6 (n = 7) or 8 mm (n = 14) in diameter. The mean follow-up period was 3.4 months (range, 1 week to 9 months). Symptoms improved in 12 (67%) patients after the procedure. There was no change in symptoms in five and a decrease in one. Twelve patients died during the follow-up period (mean survival, 4.3 months). The complication rate was 25% (six of 24 patients), including stent migration (n = 5) and fracture (n = 3).

CONCLUSION

Flexible covered metallic stent placement can be useful for palliation in patients with malignant obstruction of the gastric outlet or duodenum.

Physicochemical parameters responsible for the affinity of methotrexate analogs for rat canalicular multispecific organic anion transporter (cMOAT/MRP2)

PURPOSE

Canalicular multispecific organic anion transporter (cMOAT/MRP2) is known to exhibit a broad substrate specificity toward amphiphatic organic anions, including methotrexate (MTX). The present study aims to identify the physicochemical properties of MTX derivatives that correlate with recognition specificity by cMOAT/MRP2.

METHODS

We examined the inhibitory effect of MTX and 24 analogs on the transport of [3H]-S-(2,4-dinitrophenyl)glutathione by cMOAT/MRP2. The affinity constants of these compounds were compared with their physicochemical parameters. The primary active transport of several compounds was also confirmed.

RESULTS

The affinity constants closely correlated with the octanol/water partition coefficient (clogP), and a linear combination of polar and nonpolar surface areas. The affinity for cMOAT/MRP2 also closely correlated with the molecular weight, which also showed a significant correlation with nonpolar surface area and clogP.

CONCLUSIONS

Recognition by cMOAT/MRP2 depends on a balance of dynamic surface properties between the polar and nonpolar regions of MTX analogs. The so-called "molecular weight threshold" for the cMOAT/MRP2 affinity of these compounds can be explained by their physicochemical parameters, especially their nonpolar surface areas.

Malignant esophagogastric junction obstruction: palliative treatment with an antireflux valve stent

The authors assessed the efficacy of an antireflux valve stent in the palliation of malignant esophagogastric junction (EGJ) obstruction after in vitro testing of the stent. Seventeen patients with inoperable malignant EGJ obstruction were treated. Antireflux valves, made of three polyurethane leaflets, were attached to the distal part of the stent to prevent reflux. When the flow rate of normal saline was 100 mL/sec in the forward direction, the valve fully opened at a pressure of 10 mm Hg. When the flow rate of normal saline was 0.35 mL/sec in the backward direction, the valve nearly completely closed at a pressure of 10 mm Hg. Stent placement was successful in all patients without complications. The median dysphagia score decreased significantly, from 3.0 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food) (P < .0005). No patients experienced reflux symptoms. There was one case of stent migration. A valve stent that can prevent major reflux is an effective device for the palliation of malignant EGJ obstruction.

Biophysical characterization of recombinant human Bcl-2 and its interactions with an inhibitory ligand, antimycin A

Apoptosis is an essential physiological process, regulated by the family of Bcl-2-related proteins. However, the molecular mechanism by which Bcl-2 regulates apoptosis still remains elusive. Here we report the functional studies of recombinant human Bcl-2 with the deletion of 22 residues at the C-terminal membrane-anchoring region (rhBcl-2Delta22). Characterization of rhBcl-2Delta22 showed that the recombinant protein is homogeneous and monodisperse in nondenaturing solutions, stable at room temperature in the presence of a metal chelator, and an alpha-helical protein with unfolding of secondary structure at a T(m) of 62.8 degrees C. Optimal membrane pore formation by rhBcl-2Delta22 required negatively charged phospholipids. The existence of a hydrophobic groove in rhBcl-2Delta22 was demonstrated by the fluorescence enhancement of the hydrophobic ANS probe with which a pro-apoptotic Bak BH3 peptide competed. The respiratory inhibitor antimycin A also bound to the hydrophobic groove of rhBcl-2Delta22 with a K(d) of 0.82 microM. The optimal binding conformation of antimycin A was predicted from molecular docking of antimycin A with the hBcl-2 model created by homology modeling. Antimycin A selectively induces apoptosis in cells overexpressing Bcl-2, suggesting that hydrophobic groove-binding compounds may act as selective apoptotic triggers in tumor cells.

Crystallization of Clonorchis sinensis 26 kDa glutathione S-transferase and its fusion proteins with peptides of different lengths

A Clonorchis sinensis 26 kDa glutathione S-transferase (CsGST) and its fusion proteins containing 14 and 48 amino-acid peptides at the N-terminus have been crystallized using polyethylene glycol monomethylether 550 as a precipitant. Crystals of the three proteins show very similar crystal properties: they diffract to at least 2.3 A resolution and belong to the orthorhombic space group P2(1)2(1)2(1). The unit-cell parameters of CsGST crystals were a = 66.64 (1), b = 68.91 (1), c = 123.41 (2) A, which are very close to those of the crystals of the two fusion proteins. In addition, CsGST fusion proteins containing varying extents of N-terminal-extended peptides are incorporated into a crystal, indicating that the extended peptides have little effect on crystal packing. These results suggest that the crystallization system of CsGST/peptide fusion protein may be generally applicable to obtain crystals of small peptides.

Carrier-mediated hepatobiliary transport of a novel antifolate, N-[4-[(2,4-dianninopteridine-6-yl)methyl]-3,4-dihydro-2H-1,4-benzothiazin-7-yl]carbonyl-L-homoglutamic acid, in rats

The hepatic uptake and biliary excretion of a novel methotrexate derivative, N-[4-[(2,4-diamminopteridine-6-yl)methyl]-3,4-dihydro-2H-1,4-benzothiazin-7-yl]carbonyl-L-homoglutamic acid (MX-68), were examined in rats in vitro using isolated hepatocytes and bile canalicular membrane vesicles (CMVs), respectively. The uptake of MX-68 by isolated rat hepatocytes showed a saturable component (Km = 2.15 microM and Vmax = 2.34 pmol/min/mg of protein) and was inhibited by ATP-depletors and anionic compounds such as taurocholate and probenecid. [3H]MX-68 uptake was also inhibited by folate analogs such as methotrexate and 5CH3-tetrahydrofolate, but the effect of these compounds was slightly less than that of unlabeled MX-68. On replacing Na+ with choline, MX-68 uptake remained unchanged, whereas the methotrexate uptake was reduced. Uptake of MX-68 increased as the extracellular pH fell from 7.5 to 5.5. These results suggest that MX-68 is taken up via active transport systems. The uptake of MX-68 by CMVs prepared from normal rats exhibited clear ATP dependence, whereas ATP had only a minimal effect on the uptake by CMVs from Eisai-hyperbilirubinemic rats with a hereditary deficiency in canalicular multispecific organic anion transporter (cMOAT). The initial uptake rate of ATP-dependent MX-68 transport showed saturation with kinetic parameters similar to those of methotrexate. MX-68 inhibited the ATP-dependent transport of 2,4-dinitrophenyl-S-glutathione, a typical substrate for cMOAT, the inhibition constant (162 microM) being comparable with the Km of ATP-dependent MX-68 transport. These results suggest that the biliary excretion of MX-68 via the bile canalicular membrane is mediated mainly by cMOAT. In conclusion, active transport systems are involved in membrane penetration of MX-68 both at sinusoidal and canalicular sides in the liver, the latter being mainly involved with methotrexate (MTX) whereas the former differs partially from that for MTX.

Characterization of a novel cationic drug transporter in human retinal pigment epithelial cells

Retinal pigment epithelial (RPE) cells transport a variety of solutes, but the capacity of human RPE cells to transport drugs and xenobiotics is not well understood. As an initial step to address this issue, we have examined human RPE transport of verapamil. Transport of [3H]verapamil was measured in two human RPE cell lines (RPE/Hu and ARPE-19) grown to confluence on 12-well culture plates. Verapamil uptake by RPE/Hu cells was highly concentrative, reaching cell-to-medium ratios as high as 42 by 1 h. Uptake was saturable, with an apparent K(m) of 7.2 microM. Verapamil uptake decreased in the presence of metabolic inhibitors, low temperature, and organic cations, including quinidine, pyrilamine, quinacrine, and diphenhydramine. However, other organic cations, including tetraethylammonium and cimetidine failed to inhibit. Verapamil uptake was also inhibited by the cationic antiglaucoma drugs diltiazem, timolol, and propranolol. Verapamil uptake was insensitive to changes in membrane potential. However, transport was markedly altered by changes in pH. Decreasing external pH inhibited uptake, whereas efflux was stimulated. Intracellular acidification via NH4Cl prepulse also stimulated uptake. Identical findings were obtained using the commercially available cell line ARPE-19. In view of its unique specificity, the RPE cell verapamil transporter described above is a novel, heretofore undescribed, organic cation transporter, distinct from the known members of the OCT family of organic cation transporters.

Antimutagenic activity of 5alpha-cholest-7-en-3beta-ol, a new component from the starfish asterina pectinifera

From the butanol fraction of the starfish Asterina pectinifera Müler et Troschel (Asteriidae), we have isolated a new component, 5alpha-cholest-7-en-3beta-ol. Its antigenotoxic and antimutagenic activities were examined by the SOS chromotest with Escherichia coli PQ37 and by Ames test with Salmonella typhimurium TA1538, respectively. 5alpha-Cholest-7-en-3beta-ol showed potent antigenotoxic activity against the mutagens, both MNNG and NQO. For 100% of antigenotoxicity, the concentration of the compound applied against MNNG and NQO were 10 microg and 5 microg per reaction tube, respectively. Its antimutagenic activity with S. typhimurium TA1538 against the mutagen MNNG was very effective. When its concentrations were varied from 1 up to 10 microg dose per plate, the inhibition ratio of revertant CFU of TA1538 per plate was increased accordingly, from 25.2 to 99.2%. These results suggest that 5alpha-cholest-7-en-3beta-ol possesses antigenotoxic and antimutagenic activity and might be useful as a chemopreventive agent.

Transjugular liver biopsy: modified Ross transseptal needle versus quick-core biopsy needle

BACKGROUND

We evaluated the differences in sample adequacy and safety between a transseptal needle and Quick-core biopsy needle for transjugular liver biopsy.

METHODS

Eighteen consecutive patients who had a bleeding diatheses and/or ascites underwent transjugular liver biopsy using a transseptal needle (11 patients) and Quick-core biopsy needle (seven patients). The length of the specimens was measured before fixation. A pathologist reviewed histologic slides for sample adequacy and pathologic diagnoses. Clinical records were reviewed for complication.

RESULTS

In all patients, liver biopsy was successful. A total of 45 specimens were obtained, with an average of 2.5 passes per patient. The length of specimen was significantly longer with the Quick-core biopsy needle than with the transseptal needle (p<0.05). Biopsied tissue was fragmented in 17 of 25 specimens with the transseptal needle but not fragmented in any specimen with the Quick-core biopsy needle. All specimens were determined to be adequate except one with the transseptal needle. There was no early or delayed complication in any patient.

CONCLUSION

Transjugular liver biopsy is a safe and effective procedure without any significant difference in complication and adequacy when using a transseptal needle or Quick-core biopsy needle. Larger specimens can be obtained without tissue fragmentation with the Quick-core biopsy needle.

Binding and transport of methotrexate and its derivative, MX-68, across the brush-border membrane in rat kidney

Binding and transport properties of methotrexate (MTX) and its novel derivative, MX-68, were examined in brush-border membrane vesicles (BBMVs) isolated from rat kidneys. The uptake of MTX, MX-68 and folic acid by BBMVs was stimulated by an inwardly-directed H(+) gradient. Such H(+)-dependent uptake of folic acid is compatible with a previous report (Bhandari et al., Biochim Biophys Acta 1988; 937: 211). The MTX uptake exhibits saturation with a K(m) of 0.834 microM. Although the uptake of these three compounds at optimal pH depended on the osmolarity of the medium, a substantial portion of the uptake was osmolarity-insensitive. By changing the medium osmolarity, the uptake by BBMVs could be separately discriminated as osmolarity-sensitive and insensitive portions, representing transport into the intravesicular space and binding to the surface of BBMVs, respectively. For all three compounds, the binding increased in a time-dependent manner, while the amount transported reached a maximum after a relatively short incubation period. The transport of folic acid, but not its binding, exhibited an overshoot phenomenon under conditions of an inward H(+) gradient. The present results suggest that reabsorption of MTX and MX-68 in the kidney is governed by both their binding and transport mechanisms, with a similar kinetic profile to that of folic acid. The involvement of a transport system seems to make a relatively small contribution to the reabsorption of MTX assessed in BBMVs compared with MX-68 and folic acid.

Nonlinear disposition kinetics of a novel antifolate, MX-68, in rats

The excretion and tissue distribution kinetics of a novel antifolate, MX-68, were evaluated under conditions of a continuous steady-state infusion in Sprague-Dawley rats (SDRs). The biliary excretion clearance defined with respect to the hepatic concentration (CL(bile, h)) was much lower in Eisai hyperbilirubinemic rats with a hereditary deficiency in canalicular multispecific organic anion transporter than that in SDRs, suggesting the involvement of canalicular multispecific organic anion transporter in its transport across the bile canalicular membrane. The CL(bile, h) in SDRs increased as the infusion rate increased; this can be largely explained by saturation of the intracellular binding of MX-68. On the other hand, the urinary excretion clearance defined with respect to the renal concentration (CL(urine, k)) was comparable for the two strains but showed an increase and subsequent decrease as the renal concentration increased. This nonlinear profile was also found even when the CL(urine, k) was normalized by the unbound fraction in kidney. Therefore, this kinetic profile represents the saturation of both reabsorption and secretion. Reabsorption of MX-68 in kidney was supported by its saturable transport by renal brush border membrane vesicles at an inward H(+) gradient. The liver-to-plasma unbound concentration ratio decreased as the steady-state plasma concentration increased, suggesting that MX-68 is taken up by a saturable mechanism or mechanisms. Thus, the saturation of transport systems across several plasma membranes and intracellular binding in both the liver and kidney produce the nonlinear disposition of MX-68.

Involvement of ArcA and Fnr in expression of Escherichia coli thiol peroxidase gene

To explore the oxygen response regulators involved in thiol peroxidase gene (tpx) expression in Escherichia coli, we constructed a single-copy tpx-lacZ operon fusion and monitored tpx-lacZ expression in various genetic backgrounds. Expression of the tpx-lacZ fusion was increased 4-fold by aerobic growth. Anaerobic expression of tpx-lacZ in either (delta)arcA or delta(fnr) strains was 2.5-fold depressed compared with that of the wild-type strain. The results of immunoblotting experiments also demonstrated that ArcA and Fnr regulatory proteins repressed thiol peroxidase gene expression during anaerobic growth. Inspection of the tpx promoter region revealed putative binding sites for ArcA and Fnr. It thus appears that ArcA and Fnr function as repressors by blocking the binding of RNA polymerase to the tpx promoter in E. coli under anaerobic growth conditions.