Cloning and characterization of the thyroid iodide transporter

Iodide (I-) is an essential constituent of the thyroid hormones T3 and T4, and is accumulated by the thyroid. The transport of iodide, the first step in thyroid hormogenesis, is catalysed by the Na+/I- symporter, an intrinsic membrane protein that is crucial for the evaluation, diagnosis and treatment of thyroid disorders. Although several other important thyroid proteins involved in hormogenesis have been characterized, the Na+/I- symporter has not. Here we report the isolation of a complementary DNA clone that encodes this symporter, as a result of functional screening of a cDNA library from a rat thyroid-derived cell line (FRTL-5) in Xenopus laevis oocytes. Oocyte microinjection of an RNA transcript made in vitro from this cDNA clone elicited a more than 700-fold increase in perchlorate-sensitive Na+/I- symport activity over background. To our knowledge, this is the first iodide-transporting molecule to have its cDNA cloned, providing a missing link in the thyroid hormone biosynthetic pathway.

Diffusion spectrum magnetic resonance imaging (DSI) tractography of crossing fibers

MRI tractography is the mapping of neural fiber pathways based on diffusion MRI of tissue diffusion anisotropy. Tractography based on diffusion tensor imaging (DTI) cannot directly image multiple fiber orientations within a single voxel. To address this limitation, diffusion spectrum MRI (DSI) and related methods were developed to image complex distributions of intravoxel fiber orientation. Here we demonstrate that tractography based on DSI has the capacity to image crossing fibers in neural tissue. DSI was performed in formalin-fixed brains of adult macaque and in the brains of healthy human subjects. Fiber tract solutions were constructed by a streamline procedure, following directions of maximum diffusion at every point, and analyzed in an interactive visualization environment (TrackVis). We report that DSI tractography accurately shows the known anatomic fiber crossings in optic chiasm, centrum semiovale, and brainstem; fiber intersections in gray matter, including cerebellar folia and the caudate nucleus; and radial fiber architecture in cerebral cortex. In contrast, none of these examples of fiber crossing and complex structure was identified by DTI analysis of the same data sets. These findings indicate that DSI tractography is able to image crossing fibers in neural tissue, an essential step toward non-invasive imaging of connectional neuroanatomy.

Safety, efficacy and tumor mutational burden as a biomarker of overall survival benefit in chemo-refractory gastric cancer treated with toripalimab, a PD-1 antibody in phase Ib/II clinical trial NCT02915432

BACKGROUND

High tumor mutational burden (TMB-H) is correlated with enhanced objective response rate (ORR) and progression-free survival (PFS) for certain cancers receiving immunotherapy. This study aimed to investigate the safety and efficacy of toripalimab, a humanized programmed death-1 (PD-1) antibody, in advanced gastric cancer (AGC), and the predictive survival benefit of TMB and PD-L1.

PATIENTS AND METHODS

We reported on the AGC cohort of phase Ib/II trial evaluating the safety and activity of toripalimab in patients with AGC, oesophageal squamous cell carcinoma, nasopharyngeal carcinoma and head and neck squamous cell carcinoma. In cohort 1, 58 chemo-refractory AGC patients received toripalimab (3 mg/kg d1, Q2W) as a monotherapy. In cohort 2, 18 chemotherapy-naive AGC patients received toripalimab (360 mg d1, Q3W) with oxaliplatin 130 mg/m2 qd, d1, capecitabine 1000 mg/m2 b.i.d., d1-d14, Q3W as first-line treatment. Primary end point was ORR. Biomarkers such as PD-L1 and TMB were evaluated for correlation with clinical efficacy.

RESULTS

In cohort 1, the ORR was 12.1% and the disease control rate (DCR) was 39.7%. Median PFS was 1.9 months and median OS was 4.8 months. The TMB-H group showed significant superior OS than the TMB-L group [14.6 versus 4.0 months, HR = 0.48 (96% CI 0.24-0.96), P = 0.038], while PD-L1 overexpression did not correlate with significant survival benefit. A 77.6% of patients experienced at least one treatment-related adverse event (TRAE), and 22.4% of patients experienced a grade 3 or higher TRAE. In cohort 2, the ORR was 66.7% and the DCR was 88.9%. A 94.4% of patients experienced at least one TRAE and 38.9% of patients experienced grade 3 or higher TRAEs.

CONCLUSIONS

Toripalimab has demonstrated a manageable safety profile and promising antitumor activity in AGC patients, especially in combination with XELOX. High TMB may be a predictive marker for OS of AGC patients receiving toripalimab as a single agent.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02915432.

Thyroid Na+/I- symporter. Mechanism, stoichiometry, and specificity

The rat thyroid Na+/I- symporter (NIS) was expressed in Xenopus laevis oocytes and characterized using electrophysiological, tracer uptake, and electron microscopic methods. NIS activity was found to be electrogenic and Na+-dependent (Na+ >> Li+ >> H+). The apparent affinity constants for Na+ and I- were 28 +/- 3 mM and 33 +/- 9 microM, respectively. Stoichiometry of Na+/anion cotransport was 2:1. NIS was capable of transporting a wide variety of anions (I-, ClO3-, SCN-, SeCN-, NO3-, Br-, BF4-, IO4-, BrO3-, but perchlorate (ClO4-) was not transported. In the absence of anion substrate, NIS exhibited a Na+-dependent leak current (approximately 35% of maximum substrate-induced current) with an apparent Na+ affinity of 74 +/- 14 mM and a Hill coefficient (n) of 1. In response to step voltage changes, NIS exhibited current transients that relaxed with a time constant of 8-14 ms. Presteady-state charge movements (integral of the current transients) versus voltage relations obey a Boltzmann relation. The voltage for half-maximal charge translocation (V0.5) was -15 +/- 3 mV, and the apparent valence of the movable charge was 1. Total charge was insensitive to [Na+]o, but V0.5 shifted to more negative potentials as [Na+]o was reduced. NIS charge movements are attributed to the conformational changes of the empty transporter within the membrane electric field. The turnover rate of NIS was >/=22 s-1 in the Na+ uniport mode and >/=36 s-1 in the Na+/I- cotransport mode. Transporter density in the plasma membrane was determined using freeze-fracture electron microscopy. Expression of NIS in oocytes led to a approximately 2. 5-fold increase in the density of plasma membrane protoplasmic face intramembrane particles. On the basis of the kinetic results, we propose an ordered simultaneous transport mechanism in which the binding of Na+ to NIS occurs first.

Characterization of the thyroid Na+/I- symporter with an anti-COOH terminus antibody

The Na+/I- symporter (NIS) is the plasma membrane protein that catalyzes active I- transport in the thyroid, the first step in thyroid hormone biogenesis. The cDNA encoding NIS was recently cloned in our laboratory and a secondary structure model proposed, suggesting that NIS is an intrinsic membrane protein (618 amino acids; approximately 65.2 kDa predicted molecular mass) with 12 putative transmembrane domains. Here we report the generation of a site-directed polyclonal anti-COOH terminus NIS antibody (Ab) that immunoreacts with a approximately 87 kDa-polypeptide present in membrane fractions from a rat thyroid cell line (FRTL-5). The model-predicted cytosolic-side location of the COOH terminus was confirmed by indirect immunofluorescence experiments using anti-COOH terminus NIS Ab in permeabilized FRTL-5 cells. Immunoreactivity was competitively blocked by the presence of excess synthetic peptide. Treatment of membrane fractions from FRTL-5 cells, Xenopus laevis oocytes, and COS cells expressing NIS with peptidyl N-glycanase F converted the approximately 87 kDa-polypeptide into a approximately 50 kDa-species, the same relative molecular weight exhibited by NIS expressed in E. coli. Anti-NIS Ab immunoprecipitated both the NIS precursor molecule (approximately 56 kDa) and the mature approximately 87 kDa form. Furthermore, a direct correlation between circulating levels of thyroid-stimulating hormone and NIS expression in vivo was demonstrated.

N-linked glycosylation of the thyroid Na+/I- symporter (NIS). Implications for its secondary structure model

The Na+/I- symporter (NIS), a 618-amino acid membrane glycoprotein that catalyzes the active accumulation of I- into thyroid cells, was identified and characterized at the molecular level in our laboratory (Dai, G., Levy, O., and Carrasco, N. (1996) Nature 379, 458-460). Because mature NIS is highly glycosylated, it migrates in SDS-polyacrylamide gel electrophoresis as a broad polypeptide of higher molecular mass (approximately 90-110 kDa) than nonglycosylated NIS (approximately 50 kDa). Using site-directed mutagenesis, we substituted both separately and simultaneously the asparagine residues in all three putative N-linked glycosylation consensus sequences of NIS with glutamine and assessed the effects of the mutations on function and stability of NIS in COS cells. All mutants were active and displayed 50-90% of wild-type NIS activity, including the completely nonglycosylated triple mutant. This demonstrates that to a considerable extent, function and stability of NIS are preserved in the partial or even total absence of N-linked glycosylation. We also found that Asn225 is glycosylated, thus proving that the hydrophilic loop that contains this amino acid residue faces the extracellular milieu rather than the cytosol as previously suggested. We demonstrated that the NH2 terminus faces extracellularly as well. A new secondary structure model consistent with these findings is proposed.

Occurrence and source apportionment of pharmaceuticals and personal care products in the Beiyun River of Beijing, China

This work investigates, for the first time, the occurrence and sources of 15 pharmaceuticals and personal care products (PPCPs) in surface water of Beijing, one of most densely populated cities in the world, in three sampling events representing different seasonal flow conditions. The detection frequencies of most PPCPs were in the range of 50-100%. The median concentrations of the selected PPCPs ranged from not detected to 4200 ng L(-1) (caffeine). Generally, higher PPCP levels were observed in early spring, indicating both low flow condition and cold-water temperature might enhance their persistence. Source apportionment showed freshly discharged untreated sewage (67%) significantly contributed to the PPCP burden in the Beiyun River, which provides important information for environmental management.

Etomoxir-induced PPARalpha-modulated enzymes protect during acute renal failure

Regulation of fatty acid beta-oxidation (FAO) represents an important mechanism for a sustained balance of energy production/utilization in kidney tissue. To examine the role of stimulated FAO during ischemia, Etomoxir (Eto), clofibrate, and WY-14,643 compounds were given 5 days prior to the induction of ischemia/reperfusion (I/R) injury. Compared with rats administered vehicle, Eto-, clofibrate-, and WY-treated rats had lower blood urea nitrogen and serum creatinines following I/R injury. Histological analysis confirmed a significant amelioration of acute tubular necrosis. I/R injury led to a threefold reduction of mRNA and protein levels of acyl CoA oxidase (AOX) and cytochrome P4A1, as well as twofold inhibition of their enzymatic activities. Eto treatment prevented the reduction of mRNA and protein levels and the inhibition of the enzymatic activities of these two peroxisome proliferator-activated receptor-alpha (PPARalpha) target genes during I/R injury. PPARalpha null mice subjected to I/R injury demonstrated significantly enhanced cortical necrosis and worse kidney function compared with wild-type controls. These results suggest that upregulation of PPARalpha-modulated FAO genes has an important role in the observed cytoprotection during I/R injury.

Synthesis of 3,4-disubstituted isoquinolines via palladium-catalyzed cross-coupling of o-(1-alkynyl)benzaldimines and organic halides

[reaction: see text] 3,4-Disubstituted isoquinolines have been prepared in good yields by the palladium-catalyzed cross-coupling of N-tert-butyl-o-(1-alkynyl)benzaldimines with aryl, allylic, and alkynyl halides.

Divergent accumulation of microbial necromass and plant lignin components in grassland soils

The means through which microbes and plants contribute to soil organic carbon (SOC) accumulation remain elusive due to challenges in disentangling the complex components of SOC. Here we use amino sugars and lignin phenols as tracers for microbial necromass and plant lignin components, respectively, and investigate their distribution in the surface soils across Mongolian grasslands in comparison with published data for other grassland soils of the world. While lignin phenols decrease, amino sugars increase with SOC contents in all examined grassland soils, providing continental-scale evidence for the key role of microbial necromass in SOC accumulation. Moreover, in contrast to clay’s control on amino sugar accumulation in fine-textured soils, aridity plays a central role in amino sugar accrual and lignin decomposition in the coarse-textured Mongolian soils. Hence, aridity shifts may have differential impacts on microbial-mediated SOC accumulation in grassland soils of varied textures.

It remains unclear how microbes and plants contribute to soil organic carbon (SOC) accrual. Here, using biomarkers, the authors show that microbial necromass and plant-derived lignin components have divergent accumulation mechanisms and that microbial necromass plays a key role in SOC accumulation.

Quantitative MR imaging of carpal tunnel syndrome

OBJECTIVE

Previous MR imaging studies have produced evidence of changes to structures within the wrist believed to be associated with carpal tunnel syndrome. In an attempt to resolve the conflicting and inconclusive results of these studies, we report here the results of an MR imaging study at a field strength of 3.0 T, which is higher than that previously reported.

SUBJECTS AND METHODS

Patients with carpal tunnel syndrome and control groups of asymptomatic subjects were studied using MR imaging. We evaluated electrophysiologically the median nerve function of the affected wrists of all patients. A gradient-recalled echo pulse sequence was used to study 13 3-mm-thick slices within the wrist of each patient or asymptomatic subject. Spatial resolution was approximately 0.3 x 0.3 mm2. The median nerve and other structures associated with the carpal tunnel, which were clearly shown on the MR images, were analyzed to yield structural data.

RESULTS

Analysis revealed that the cross-sectional area of the nerve within and proximal to the carpal tunnel was approximately 50% larger in patients with carpal tunnel syndrome than in asymptomatic subjects. We found no significant difference in the area of the nerve within the carpal tunnel compartment compared with the area of the nerve proximal to the carpal tunnel either in patients or in asymptomatic subjects. Also, flattening of the nerve on entering the carpal tunnel was not significantly different in patients than in asymptomatic subjects. In patients an increase in the palmar bowing of the flexor retinaculum was found only at the level of the hamate compared with that found in asymptomatic subjects. The cross-sectional area of the carpal tunnel was of a similar size in patients and in asymptomatic subjects. Comparison of electrodiagnostic results indicated no correlations between the MR parameters and electrophysiologic dysfunction of the median nerve for patients.

CONCLUSION

The only statistically significant differences found between patients with carpal tunnel syndrome and asymptomatic subjects were that the median nerve was approximately 50% larger within and proximal to the carpal tunnel in patients with carpal tunnel syndrome and palmar bowing of the flexor retinaculum occurred in patients only at the level of the hamate.

Altered cytokine production and impaired antimycobacterial immunity in protein-malnourished guinea pigs

Protein malnutrition leads to multiple detrimental alterations of host immune responses to mycobacterial infection. In this study, we demonstrated that splenocytes from low-protein (LP) guinea pigs vaccinated 6 weeks previously with attenuated Mycobacterium tuberculosis H37Ra failed to control the accumulation of virulent M. tuberculosis H37Rv in cocultured autologous peritoneal macrophages, despite the fact that they were able to control the accumulation of virulent tubercle bacilli in cocultured syngeneic peritoneal macrophages from normally nourished guinea pigs as successfully as did those from high-protein (HP) counterparts. Vaccine-induced growth control of virulent M. tuberculosis H37Rv in these cocultures appeared to be mediated by CD4 lymphocytes but not CD8 cells. Tuberculin (purified protein derivative [PPD])-induced lymphoproliferation was markedly impaired in vaccinated LP guinea pigs, and the depletion of CD4 lymphocytes significantly decreased lymphocyte proliferation whereas CD8 cell depletion did not. Protein malnutrition also impaired the abilities of cells from vaccinated LP guinea pigs to produce cytokines, including interferon, tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta), in response to PPD, despite the demonstration of higher serum levels of TNF-alpha and TGF-beta after an intravenous injection of PPD into LP guinea pigs. In contrast, peritoneal macrophages from protein-malnourished guinea pigs produced a higher level of TGF-beta 4 days after infection in vitro with M. tuberculosis H37Rv than did those from protein adequate controls. These results suggest that dietary protein malnutrition impairs vaccine-induced resistance to M. tuberculosis, in part, by altering the cytokine profile to favor macrophage deactivation.

Na(+)-I- symport activity is present in membrane vesicles from thyrotropin-deprived non-I(-)-transporting cultured thyroid cells

The active accumulation of I- in the thyroid gland is mediated by the Na(+)-I- symporter and driven by the Na+ gradient generated by the Na+/K(+)-ATPase. Thyrotropin (TSH) stimulates thyroidal I- accumulation. Rat thyroid-derived FRTL-5 cells require TSH to accumulate I-. TSH withdrawal for over 7 days results in complete loss of Na(+)-I-symport activity in these cells [Weiss, S. J., Philp, N. J. and Grollman, E. F. (1984) Endocrinology 114, 1090-1098]. Surprisingly, membrane vesicles prepared from FRTL-5 cells maintained in TSH-free medium [TSH(-)cells]accumulate I-, suggesting that the absence of Na(+)-I- symport activity in TSH(-) cells cannot be due solely to a decrease in the biosynthesis of either the symporter or a putative activating factor. This finding indicates that the Na(+)-I- symporter is present, probably in an inactive state, in TSH(-) cells despite their lack of Na(+)-I- symport activity. Na(+)-I- symport activity in thyroid membrane vesicles is enhanced when conditions for vesicle preparation favor proteolysis. Subcellular fractionation studies in both TSH(+) and TSH(-) cells show that Na(+)-I- symport activity is mostly associated with fractions enriched in plasma membrane rather than in intracellular membranes, suggesting that the Na(+)-I- symporter may constitutively reside in the plasma membrane and may be activated by TSH.

Purification of a novel calcium-independent phospholipase A2 from rabbit kidney

We have recently identified a cytosolic calcium-independent phospholipase A2 (PLA2) that represents the major measurable PLA2 activity in rabbit proximal tubules (Portilla, D., Shah, S. V., Lehman, P. A., and Creer, M. H.(1994) J. Clin. Invest. 93, 1609-1615). We now report the 3200-fold purification of this PLA2 to homogeneity from rabbit kidney cortex through sequential column chromatography including anion exchange, hydrophobic interaction, Mono Q, hydroxylapatite, phenyl-Sepharose, and chromatofocusing fast protein liquid chromatography from rabbit kidney cortex. The purified enzyme had a molecular mass of 28 kDa, possessed a specific activity of 1.2 micronol/mg min and a neutral pH optimum, and exhibited a preferential hydrolysis toward sn-2 fatty acid from diradylglycerophospholipids. The purified polypeptide hydrolyzed plasmenylcholine > phosphatidylcholine glycerophospholipids and selectively cleaved phospholipids containing arachidonic acid at the sn-2 position in comparison to oleic acid. Antibodies against the purified protein precipitated all of the soluble calcium-independent PLA2 activity from rabbit kidney cortex. These data altogether suggest that the 28-kDa protein in the kidney represents a novel class of calcium-independent PLA2.

Distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface water and sediments from Baiyangdian Lake in North China

Persistent organochlorine compounds, including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and polychlorinated biphenyls (PCBs) were analyzed in surface water and sediments from Baiyangdian Lake, North China. Total concentrations of HCHs, DDTs and PCBs in surface water were in the range of 3.13-10.60, 4.05-20.59 and 19.46-131.62 ng/L, respectively, and total concentrations of HCHs, DDTs and PCBs in sediments were 1.75-5.70, 0.91-6.48 and 5.96-29.61 ng/g dry weight, respectively. Among the groups of HCHs (sum of alpha-HCH, beta-HCH, gamma-HCH and delta-HCH) and DDTs (sum of DDT, DDD and DDE), the predominance of beta-HCH, DDE and DDD in water and sediment samples was clearly observed. This observation suggested that beta-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD. For PCBs, penta-, hexa- and hepta-chlorinated congeners were the most abundant compounds in the both phases. Furthermore, the partitioning of chlorinated compounds between sediment and water was investigated to understand their transport and fates in aquatic ecosystems. The results indicated that average logs of organic carbon-normalized sediment-water partition coefficients (logK'(oc)) for OCPs varied between 3.20 and 5.53, and for PCBs, logK'(oc) values ranged from 3.19 to 5.57. The observed logK'(oc) was lower than their equilibrium logK(oc) predicted from linear model, which may be attributed to the solubility enhancement effect of colloidal matter in water phase and the disequilibrium between sediment and water.

The effects of external compression on venous blood flow and tissue deformation in the lower leg

External pneumatic compression of the lower legs is effective as prophylaxis against deep vein thrombosis. In a typical application, inflatable cuffs are wrapped around the patient's legs and periodically inflated to prevent stasis, accelerate venous blood flow, and enhance fibrinolysis. The purpose of this study was to examine the stress distribution within the tissues, and the corresponding venous blood flow and intravascular shear stress with different external compression modalities. A two-dimensional finite element analysis (FEA) was used to determine venous collapse as a function of internal (venous) pressure and the magnitude and spatial distribution of external (surface) pressure. Using the one-dimensional equations governing flow in a collapsible tube and the relations for venous collapse from the FEA, blood flow resulting from external compression was simulated. Tests were conducted to compare circumferentially symmetric (C) and asymmetric (A) compression and to examine distributions of pressure along the limb. Results show that A compression produces greater vessel collapse and generates larger blood flow velocities and shear stresses than C compression. The differences between axially uniform and graded-sequential compression are less marked than previously found, with uniform compression providing slightly greater peak flow velocities and shear stresses. The major advantage of graded-sequential compression is found at midcalf. Strains at the lumenal border are approximately 20 percent at an external pressure of 50 mmHg (6650 Pa) with all compression modalities.

Uterine natural killer cells are targets for a trophoblast cell-specific cytokine, prolactin-like protein A

PRL-like protein A (PLP-A) is a member of the PRL family expressed in trophoblast cells coincident with establishment of the chorioallantoic placenta. The purpose of this investigation was to identify targets for PLP-A. Using an alkaline phosphatase-tagging strategy, we show that PLP-A specifically interacts with a population of natural killer (NK) lymphocytes within the mesometrial compartment of decidua from pregnant and pseudopregnant rats. These observations are supported by the codistribution of PLP-A targets with cells expressing the rat NK cell surface marker, gp42, the absence of PLP-A binding in conceptuses from NK cell-deficient tg epsilon26 mice, and the specific interaction of PLP-A with a rat NK cell line, RNK-16. We have further demonstrated that PLP-A effectively suppresses RNK-16 cell cytolytic activities. Our results provide evidence for a new paradigm of embryonic-maternal communication involving a PLP-A signaling pathway between trophoblast cells and uterine NK lymphocytes.

Quantitatively modeling soil-water distribution coefficients of three antibiotics using soil physicochemical properties

Using 14 parameters featuring soil physicochemical properties and the partial least squares (PLSs) regression method, three quantitative models were respectively developed for the soil-water distribution coefficients (logK(d)) of oxytetracycline (OTC), sulfamethazine (SMZ) and norfloxacin (NOR) in 23 Chinese natural soil samples from cultivated lands in 19 provinces of China. The cross-validated correlation coefficients (Q(cum)(2)) of three models are 0.866, 0.765 and 0.868, and the standard deviations (SDs) are 0.16, 0.21 and 0.15 respectively. The high Q(cum)(2) and low SD values indicate that three models have high robustness and precise predictability. Six parameters including pH, clay content, free Fe oxides (DCB-Fe), free Al oxides (DCB-Al), Ca content and Al content are greatly significant in the OTC model, three ones including pH, clay content and DCB-Fe are greatly significant in the SMZ model, and five ones including pH, clay content, DCB-Fe, Ca content and organic matter (OM) are greatly significant in the NOR model. The high VIP values of pH (1.17-1.24), clay content (0.81-1.10) and DCB-Fe (0.90-0.99) show that the three sorts of soil physicochemical properties play dominant roles in governing the partition balance between soil and water of three antibiotics.

Co-inheritance of the polymorphic metabolism of encainide and debrisoquin

O-demethylation of the investigational antiarrhythmic encainide was found to be correlated with the genetically determined hydroxylation of debrisoquin in 20 randomly selected and unrelated subjects and in five members of one family. Extensive metabolizers of debrisoquin had a mean (+/- SD) encainide elimination t1/2 of 1.19 +/- 0.98 hours (range 0.25 to 3.4 hours). Poor metabolizers of debrisoquin (two normal subjects and three family members) had a mean t1/2 of 13.2 +/- 0.73 hours (range 7.8 to 22.4 hours). The elimination rate constant of encainide and the fractional excretion of O-desmethyl encainide in urine were linearly related to the fractional urinary excretion of 4-hydroxy-debrisoquin. Poor metabolizers could be identified after a 50 mg dose of encainide by the fractional excretion of O-desmethyl encainide in urine or the absence of (1) measurable ECG changes or (2) O-desmethyl encainide in plasma. The correlation between excretion of O-desmethyl encainide and 4-hydroxy-debrisoquin suggests that significant numbers of the caucasian population (7% to 9%) are likely to be poor metabolizers of encainide and to have markedly different pharmacokinetics and plasma concentration-response relationships than extensive metabolizers.

MicroRNA-223-3p inhibits the angiogenesis of ischemic cardiac microvascular endothelial cells via affecting RPS6KB1/hif-1a signal pathway

Background

MicroRNAs (miRNAs) are a recently discovered class of posttranscriptional regulators of gene expression with critical functions in the angiogenesis and cardiovascular diseases; however, the details of miRNAs regulating mechanism of angiogenesis of ischemic cardiac microvascular endothelial cells (CMECs) are not yet reported.

Methods and Results

This study analyzes the changes of the dynamic expression of miRNAs during the process of angiogenesis of ischemic CMECs by applying miRNA chip and real-time PCR for the first time. Compared with normal CMECs, ischemic CMECs have a specific miRNAs expression profile, in which mir-223-3p has the most significant up-regulation, especially during the process of migration and proliferation, while the up-regulation is the most significant during migration, reaching 11.02 times. Rps6kb1 is identified as a potential direct and functional target of mir-223-3p by applying bioinformatic prediction, real-time PCR and Western blot. Pathway analysis report indicates Rps6kb1 regulates the angiogenesis by participating into hif-1a signal pathway. Further analysis reveals that both the gene and protein expression of the downstream molecules VEGF, MAPK, PI3K and Akt of Rps6kb1/hif-1a signal pathway decrease significantly during the process of migration and proliferation in the ischemic CMECs. Therefore, it is confirmed that mir-223-3p inhibits the angiogenesis of CMECs, at least partly, via intervening RPS6KB1/hif-1a signal pathway and affecting the process of migration and proliferation.

Conclusion

This study elucidates the miRNA regulating law in the angiogenesis of CMECs; mir-223-3p inhibits the process of migration and proliferation of ischemic CMECs probably via affecting RPS6KB1/hif-1a signal pathway, which in turn suppresses the angiogenesis. It is highly possible that mir-223-3p becomes a novel intervention core target in the treatment of angiogenesis of ischemic heart diseases.

Major pharmaceuticals and personal care products (PPCPs) in wastewater treatment plant and receiving water in Beijing, China, and associated ecological risks

The occurrence of 15 pharmaceuticals and personal care products in the influent and effluent from the wastewater treatment plant (WWTP) and its receiving water in Beijing, China were determined. Results from the present study confirmed that caffeine, N,N-diethyl-m-toluamide and chloramphenicol were removed at a high rate (>70 % efficiency). In contrast, removal efficiency of the other 12 compounds was quite poor (ranged from -40 % to 58 %). Some compounds in the receiving river were present at higher concentrations compared to those in the WWTP effluent, indicating that sources other than treated effluents are present. The risk to the aquatic environment was estimated by a ratio of measured environmental concentration and predicted no-effect concentration. For those compounds found in the effluent and surface water, mefenamic acid, trimethoprim and gemfibrozil may pose a medium risk to aquatic environment.

Allocation of helper T-cell epitope immunodominance according to three-dimensional structure in the human immunodeficiency virus type I envelope glycoprotein gp120

The specificity and intensity of CD4(+) helper T-cell responses determine the effectiveness of immune effector functions. Promiscuously immunodominant helper T-cell epitopes in the human immunodeficiency virus (HIV) envelope glycoprotein gp120 could be important in the development of broadly protective immunity, but the underlying mechanisms of immunodominance and promiscuity remain poorly defined. In this study, gp120 helper T-cell epitopes were systematically mapped in CBA/J and BALB/c mice by restimulation assays using a set of overlapping peptides spanning the entire sequence of the gp120 encoded by HIV strain 89.6. The results were analyzed in the context of the HIV gp120 structure determined by x-ray crystallography. One major finding was that all of the promiscuously immunodominant gp120 sequences are located in the outer domain. Further analyses indicated that epitope immunogenicity in the outer domain correlates with structural disorder in adjacent N-terminal segments, as indicated by crystallographic B-factors or sequence divergence. In contrast, the correlation was poor when the analysis encompassed the entire gp120 sequence or was restricted to only the inner domain. These findings suggest that local disorder promotes the processing and presentation of adjacent epitopes in the outer domain of gp120 and therefore reveal how three-dimensional structure shapes the profile of helper T-cell epitope immunogenicity.