Macroscopic chirality of a liquid crystal from nonchiral molecules

The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment.

Copy Number Variations with Isolated Fetal Ventriculomegaly

BACKGROUND

Copy Number Variations (CNVs) are an important genetic cause of a number of neurodevelopmental disorders (NDs). However, the association between CNVs and the development and prognosis of fetal isolated mild ventriculomegaly (IMV) is unclear.

OBJECTIVES

To investigate possible associations between CNVs and the development of fetal IMV.

METHODS

This retrospective study recruited 154 subjects with ultrasound-confirmed fetal IMV and 190 subjects in a control cohort who underwent a high-risk prenatal serum screening program. The exclusion criteria included fetus G-banding chromosomal abnormality or positive fetus TORCH infection. DNA samples from all 344 fetuses were examined by an SNP-array. Developmental outcomes were assessed during postnatal follow-up.

RESULTS

Fourteen pathogenic CNVs (pCNVs) were identified in 13 out of 154 IMV fetuses. Three pCNVs were found in 3 out of 190 subjects in the prenatal screening high-risk cohort, with a significant difference (P value=0.016, X2 test). Notably, the 14 pCNVs detected in the IMV cohort were all associated with neurodevelopmental disorders (NDs), including autism, intellectual disability. Among the 13 IMV fetuses carrying pCNVs, five subjects were found in the postnatal follow-up to manifest NDs, including two with autism and three with mild neurodevelopmental delay. The other 8 subjects consisted of three normal infants younger than 12-months old, two lost in the follow-up, and three with the termination of pregnancy. Out of 141 IMV subjects without detectable pCNVs, 123 subjects showed normal development, 16 were lost in the follow-up, 2 subjects terminated the pregnancy due to fetal hydrocephalus or congenital heart disease in the late fetus development.

CONCLUSIONS

This study suggests an association between pCNVs and fetal IMV. pCNVs may be involved in the pathological process of fetal IMV and postnatal NDs. Identifying specific genomic alterations may provide an insight into pathogenetic mechanism and aid better diagnosis and prognosis of neurodevelopmental outcomes in fetal IMV.

A neural network model of causality

This paper proposes a model for commonsense causal reasoning, based on the basic idea of neural networks. After an analysis of the advantages and limitations of existing accounts of causality, a fuzzy logic based formalism FEL is proposed that takes into account the inexactness and the cumulative evidentiality of commonsense causal reasoning, overcoming the limitations of existing accounts. Analyses concerning how FEL handles various aspects of commonsense causal reasoning are performed, in an abstract way. FEL can be implemented (naturally) in a neural (connectionist) network. This work also serves to link rule-based reasoning with neural network models, in that a rule-encoding scheme (FEL) is equated directly to a neural network model.

Sp1 binds to the precise locus of end processing within the terminal repeats of Epstein-Barr virus DNA

Interconversion between the linear genome of Epstein-Barr virus (EBV) present in virions and intracellular circular EBV DNA is a novel DNA recombination process. A previously characterized DNA binding activity called terminal repeat or tandem repeat binding protein (TRBP) was found to recognize several G-rich recombinogenic sequences in the EBV genome and in cellular DNA. TRBP was also found to be an autoantigen recognized by sera from certain patients with undifferentiated connective-tissue disorders. Here the transcription factor Sp1 has been identified as a component of TRBP and has been shown to be an autoantigen. Sp1 bound to recombination junctions of EBV DNA, such as those in the terminal repeats and in the large internal repeats, as well as to recombinogenic regions of cellular DNA, such as variable-number tandem repeats and switch regions of the immunoglobulin genes. We defined the ends of the linear EBV genome present in virions and showed that Sp1 binds to the sequence (GGGGTGGGGCATGGG) within EBV terminal repeats at the precise locus of interconversion of linear and circular viral DNA. Sp1 may be involved in DNA recombination.

Dihydrofolate reductase from Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is the first human virus known to encode dihydrofolate reductase (DHFR), an enzyme required for nucleotide and methionine biosynthesis. We have studied the purified KSHV-DHFR enzyme in vitro and analyzed its expression in cultured B-cell lines derived from primary effusion lymphoma (PEL), an AIDS-associated malignancy. The amino acid sequence of KSHV-DHFR is most similar to human DHFR (hDHFR), but the viral enzyme contains an additional 23 amino acids at the carboxyl-terminus. The viral DHFR, overexpressed and purified from E. coli, was catalytically active in vitro. The K(m) of KSHV-DHFR for dihydrofolate (FH(2)) was 2.4 microM, which is significantly higher than the K(m) of recombinant hDHFR (rhDHFR) for FH(2) (390 nM). K(m) values for NADPH were similar for the two enzymes, about 1 microM. KSHV-DHFR was inhibited by folate antagonists such as methotrexate (K(i): 200 pM), aminopterin (K(i): 610 pM), pyrimethamine (K(i): 29 nM), trimethoprim (K(i): 2.3 microM), and piritrexim (K(i): 3.9 nM). In all cases, K(i) values for these folate antagonists were higher for KSHV-DHFR than for rhDHFR. The viral enzyme was expressed at levels two- to tenfold higher than hDHFR in PEL cell lines as an early lytic cycle gene. KSHV-DHFR mRNA and protein appeared from 6 to 24 h after chemical induction of the KSHV lytic cycle. Epitope-tagged KSHV-DHFR and rhDHFR both localized to the nucleus of transfected cells, while other KSHV nucleotide metabolism genes localized to the cytoplasm. DHFR activity was not essential for viral replication in cultured PEL cells. Since hDHFR was not detectable in peripheral blood mononuclear cells (PBMCs), KSHV-DHFR may function to provide increased DHFR activity in vivo in infected cells that have little or none of their own enzyme.

Temporal trends and factors associated with survival after Pneumocystis carinii pneumonia in California, 1983-1992

The authors investigated quarterly trends in survival after the diagnosis of Pneumocystis carinii pneumonia for 19,607 patients in California in the decade from January 1, 1983, through December 31, 1992. Subjects included all cases for whom P. carinii pneumonia was the initial (and only) acquired immunodeficiency syndrome (AIDS)-defining diagnosis as reported to the California human immunodeficiency virus/AIDS surveillance registry. There was a period of rapidly improving survival from approximately June 1986 until April 1988, coincident with the widespread introduction of antiretroviral therapy (zidovudine) and the institution of P. carinii pneumonia prophylaxis (with cotrimoxazole and pentamidine). There was no evidence, however, of meaningful improvements in survival for these patients after that period. The association of several covariates (risk transmission group, gender, race/ethnicity, certainty of P. carinii pneumonia diagnosis, age, region of residence, availability of CD4 count, and level of CD4 count) were also studied both by proportional hazards regression and by recursive partitioning (i.e., tree-based) survival analysis. The availability of a CD4 count (regardless of its level) was the single factor most strongly associated with survival (median survival 36 months among those with and 14 months among those without reported CD4 counts, p < 0.05). Data from this large, population-based surveillance registry of AIDS in California suggest that, despite earlier improvements in survival after the diagnosis of P. carinii pneumonia, the long-term survival of these patients remains poor (39% alive 2 years after diagnosis) and that no improvement in survival has occurred since 1988.

Uncoupling protein1 mRNA, mitochondrial GTP-binding, and T4 5'-deiodinase of brown adipose tissue in euthermic Daurian ground squirrel during cold exposure

Regulation of thermogenic activity and uncoupling protein1 (UCP1) expression in brown adipose tissue (BAT) were studied in euthermic Daurian ground squirrel after acute and chronic cold exposure at 4 degrees C. The UCP1 concentration was indirectly determined by titration with its specific ligand [3H]-labeled GTP, and Ucp1 mRNA was detected by using a [32P]-labeled antisense oligonucleotide probe. Both acute and chronic cold exposure stimulated up-regulation of Ucp1 mRNA. Although UCP1 concentration is not significantly increased after 24 h of cold exposure, it is markedly elevated by 75% in squirrels after 4-week cold adaptation compared with controls raised at 22 degrees C. Changes in T4 5'-deiodinase activity were closely associated with variations of Ucp1 mRNA level. Ucp1 gene expression is significantly affected by cold exposure in BAT from euthermic Daurian ground squirrels. In addition, the activation of T4 5'-deiodinase may be an important regulatory factor in cold-induced Ucp1 expression.

A novel lift-off method for fabricating patterned and vertically-aligned W18O49 nanowire arrays with good field emission performance

A novel lift-off method has been developed for fabricating patterned W(18)O(49) nanowires in vertical arrays and on a large scale. These W(18)O(49) nanowire arrays have an average diameter of about 30 nm, and their lengths range from 2-3 μm. In every pattern of a 2 inch sample, the nanowires exhibit the same morphology and growth density. They are single crystals with monoclinic structure and grow along the [010] direction. Field emission (FE) measurements show that they have a turn-on field of 6.2 V μm(-1) and their emission current density can reach 500 μA cm(-2) at an electric field of 10.9 V μm(-1). Because the W(18)O(49) nanowire patterns synthesized by this simple method still have good FE performance, comparable to many cathode nanostructures with excellent FE properties, it suggests that it may provide an effective and simple preparation technique for patterned growth of nanowire arrays in future FE applications.

Autoantigenic proteins that bind recombinogenic sequences in Epstein-Barr virus and cellular DNA

We have identified conserved autoantigenic cellular proteins that bind to G-rich sequence motifs in recombinogenic regions of Epstein-Barr virus (EBV) DNA. This binding activity, called TRBP, recognizes the EBV terminal repeats, a locus responsible for interconversion of linear and circular EBV DNA. We found that TRBP also binds to EBV DNA sequences involved in deletion of EBNA2, a gene product required for immortalization. We show that TRBP binds sequences present in repetitive cellular DNA, such as variable-number tandem repeats (VNTR) and immunoglobulin heavy-chain class switch regions. We propose that EBV utilizes cellular DNA recombination systems to mediate several types of viral genome alterations. These findings may lead to an understanding of the mechanism of rearrangements of EBV DNA that are a central feature of the biology of the virus.

Mapping the orientation of an antigenic peptide bound in the antigen binding groove of H-2Kb using a monoclonal antibody

The major histocompatibility complex class I molecules are receptors for intracellular peptides, both of self and non-self origin. When non-self peptides (eg., pathogen derived) are bound to the class I molecules, they form ligands for T cell receptors resulting in antigen specific lysis of the infected cells by cytotoxic T lymphocytes. Therefore, an understanding of the process of antigen recognition requires the precise definition of the structural features of the bimolecular complex formed by a single well defined antigenic peptide bound to the class I molecule. A strategy using antibodies was developed to probe the structural features of the H-2Kb containing a defined peptide in the antigen cleft. We report that the binding surface area of a Kb specific monoclonal antibody (28-13-3s) includes residues in the alpha 1 (Gly56 and Glu58) and alpha 2 (Trp167) helices of Kb thus, binding across the antigen binding groove. When cells treated with the antigenic peptide of vesicular stomatitis virus, N52-59, and its alanine substituted analogs were tested for 28-13-3s binding, it was found that position 1 of the peptide also forms a part of the antibody binding site. This finding strongly supports the positioning of the N-terminus of N52-59 proximal to pocket A, thus, assuming an orientation parallel to the alpha 1 helix.

[Non-targeted effects (bystander, abscopal) of external beam radiation therapy: an overview for the clinician]

Radiotherapy is advocated in the treatment of cancer of over 50 % of patients. It has long been considered as a focal treatment only. However, the observation of effects, such as fatigue and lymphopenia, suggests that systemic effects may also occur. The description of bystander and abscopal effects suggests that irradiated cells may exert an action on nearby or distant unirradiated cells, respectively. A third type of effect that involves feedback interactions between irradiated cells was more recently described (cohort effect). This new field of radiation therapy is yet poorly understood and the definitions suffer from a lack of reproducibility in part due to the variety of experimental models. The bystander effect might induce genomic instability in non-irradiated cells and is thus extensively studied for a potential risk of radiation-induced cancer. From a therapeutic perspective, reproducing an abscopal effect by using a synergy between ionizing radiation and immunomodulatory agents to elicit or boost anticancer immune responses is an interesting area of research. Many applications are being developed in particular in the field of hypofractionated stereotactic irradiation of metastatic disease.

The Inflammatory Heart Diseases: Causes, Symptoms, and Treatments

The inflammation of the heart muscles, such as myocarditis, the membrane sac which surrounds the heart called as pericarditis, and the inner lining of the heart or the myocardium, heart muscle as endocarditis are known as the inflammatory heart diseases. Inflammation of heart is caused by known infectious agents, viruses, bacteria, fungi or parasites, and by toxic materials from the environment, water, food, air, toxic gases, smoke, and pollution, or by an unknown origin. Myocarditis is induced by infection of heart muscle by virus like sarcoidosis and immune diseases. The symptoms include chest pain, angina, pain in heart muscle, and shortness of breath, edema, swelling of feet or ankles, and fatigue. The ECG, X-ray, and MRI can diagnose the disease; blood test and rise in enzymes levels provide abnormality in heart function. The treatment includes use of antibiotics for inflammation of heart muscle and medications. The ultrasound imaging indicates further damage to the heart muscle. In severe cases of infection heart failure can occur so long-term medications are necessary to control inflammation. The various biomarkers are reported for the inflammatory heart diseases. The causes, symptoms and treatments of inflammatory heart diseases are described.

Area postrema syndrome as initial manifestation in neuromyelitis optica spectrum disorder patients: A retrospective study

BACKGROUND

Area postrema syndrome (APS) is recognized as a core feature in neuromyelitis optica (NMO) diagnosis. Isolated APS can occur at NMO onset and frequently results in a delay of diagnosis, along with devastating secondary neurologic deficits. To date, few studies have characterized APS-onset neuromyelitis optica spectrum disorder (APSO-NMOSD).

OBJECTIVE

We aimed to describe the clinical and radiologic features of patients with APSO-NMOSD who are initially misdiagnosed in a cohort of patients from Zhengzhou, China.

MATERIALS AND METHODS

We identified 15 patients who presented with APS as an initial manifestation, based on the 2015 international consensus diagnostic criteria for NMOSD, and reviewed their demographic, clinical, laboratory, and magnetic resonance imaging (MRI) data.

RESULT

Fifteen patients (3 men, 12 women) aged 14-50 years old were included in our study. All patients presented with APS that included intractable nausea, vomiting, or hiccups (INVH) as the initial manifestation; many experienced a delay in diagnosis. Serum AQP4 was positive in eleven patients and myelin oligodendrocyte glycoprotein (MOG) in one patient. All patients had a linear medullary lesion or a linear medulla-spinal lesion on sagittal MRI. An "inverted V sign" on axial medulla oblongata images, representing a lesion involving the area postrema, was noted in seven patients in this study.

CONCLUSIONS

APS can occur as a sole and initial manifestation of NMOSD, often leading to misdiagnosis in the early process of disease. Identifying patients with an "inverted V" sign and a linear medullary lesion upon MRI examination can help to quickly identify APS patients and avoid further diagnostic delays.

Metastatic small bowel adenocarcinoma: role of metastasectomy and systemic chemotherapy

Background

Metastatic small bowel adenocarcinoma (SBA) has a poor prognosis. Due to its rarity, high-quality data are lacking to guide treatment. This retrospective analysis was conducted to help characterize the treatment options for patients with metastatic SBA while providing clinically meaningful prognostic information.

Patients and methods

In total, 437 patients who initially presented with or developed metastatic SBA between September 1977 and September 2019 were identified from the MD Anderson Tumor Registry. Clinical data were collected from review of the medical record. Overall response rates (ORR), time to progression (TTP), and overall survival (OS) were assessed across various treatments and treatment lines.

Results

The median OS from diagnosis of metastatic disease was 15.9 months [95% confidence interval (CI): 14.3-17.9]. Seventy-five patients (17.1%) underwent metastasectomy, which was associated with a median OS of 34.5 versus 17.1 months among patients who received chemotherapy alone (P < 0.001). Fluoropyrimidine plus platinum (n = 164) was the most common first-line chemotherapy, associated with an ORR of 59% and TTP of 8.1 months. Irinotecan with 5-FU (n = 101) was the most common second-line therapy associated with an ORR of 31% and TTP of 4.0 months. Twenty-two patients received immunotherapy; 5 of 6 patients with deficient mismatch repair (dMMR) responded, while 0 of 16 with proficient mismatch repair (pMMR) responded. Taxane-based chemotherapy was given to 34 patients with an ORR of 21% and a median TTP of 2.4 months. Among 11 patients who received anti-epidermal-growth-factor-receptor (EGFR) monotherapy, the best response was stable disease (SD) in 1 patient.

Conclusions

In well-selected patients with SBA, metastasectomy appears to be associated with improved OS. This improvement was seen across metastasectomy sites, including liver, lung and peritoneal. Anti-programmed cell death protein 1 (PD-1) based immunotherapy was active for dMMR SBA but not pMMR SBA. While taxane-based chemotherapy demonstrates therapeutic activity, the activity of anti-EGFR therapy was limited.

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Metastasectomy for well-selected metastatic SBA patients was associated with improved OS.

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Anti-PD1-based immunotherapy was active for dMMR SBA but not pMMR SBA.

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Taxane-based chemotherapy demonstrated clinical activity in refractory SBA.

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Anti-EGFR therapy demonstrated minimal activity in SBA.

Observation and simulation of net primary productivity in Qilian Mountain, western China

We modeled net primary productivity (NPP) at high spatial resolution using an advanced spaceborne thermal emission and reflection radiometer (ASTER) image of a Qilian Mountain study area using the boreal ecosystem productivity simulator (BEPS). Two key driving variables of the model, leaf area index (LAI) and land cover type, were derived from ASTER and moderate resolution imaging spectroradiometer (MODIS) data. Other spatially explicit inputs included daily meteorological data (radiation, precipitation, temperature, humidity), available soil water holding capacity (AWC), and forest biomass. NPP was estimated for coniferous forests and other land cover types in the study area. The result showed that NPP of coniferous forests in the study area was about 4.4 tCha(-1)y(-1). The correlation coefficient between the modeled NPP and ground measurements was 0.84, with a mean relative error of about 13.9%.

Application of a new leaf area index algorithm to China's landmass using MODIS data for carbon cycle research

An operational system was developed for mapping the leaf area index (LAI) for carbon cycle models from the moderate resolution imaging spectroradiometer (MODIS) data. The LAI retrieval algorithm is based on Deng et al. [2006. Algorithm for global leaf area index retrieval using satellite imagery. IEEE Transactions on Geoscience and Remote Sensing, 44, 2219-2229], which uses the 4-scale radiative transfer model [Chen, J.M., Leblancs, 1997. A 4-scale bidirectional reflection model based on canopy architecture. IEEE Transactions on Geoscience and Remote Sensing, 35, 1316-1337] to simulate the relationship of LAI with vegetated surface reflectance measured from space for various spectral bands and solar and view angles. This algorithm has been integrated to the MODISoft platform, a software system designed for processing MODIS data, to generate 250 m, 500 m and 1 km resolution LAI products covering all of China from MODIS MOD02 or MOD09 products. The multi-temporal interpolation method was implemented to remove the residual cloud and other noise in the final LAI product so that it can be directly used in carbon models without further processing. The retrieval uncertainties from land cover data were evaluated using five different data sets available in China. The results showed that mean LAI discrepancies can reach 27%. The current product was also compared with the NASA MODIS MOD15 LAI product to determine the agreement and disagreement of two different product series. LAI values in the MODIS product were found to be 21% larger than those in the new product. These LAI products were compared against ground TRAC measurements in forests in Qilian Mountain and Changbaishan. On average, the new LAI product agrees with the field measurement in Changbaishan within 2%, but the MODIS product is positively biased by about 20%. In Qilian Mountain, where forests are sparse, the new product is lower than field measurements by about 38%, while the MODIS product is larger by about 65%.