Room-Temperature Quantum Hall Effect in Graphene

The quantum Hall effect (QHE), one example of a quantum phenomenon that occurs on a truly macroscopic scale, has attracted intense interest since its discovery in 1980 and has helped elucidate many important aspects of quantum physics. It has also led to the establishment of a new metrological standard, the resistance quantum. Disappointingly, however, the QHE has been observed only at liquid-helium temperatures. We show that in graphene, in a single atomic layer of carbon, the QHE can be measured reliably even at room temperature, which makes possible QHE resistance standards becoming available to a broader community, outside a few national institutions.

De-escalating and escalating treatments for early-stage breast cancer: the St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017

The 15th St. Gallen International Breast Cancer Conference 2017 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. Treatments were assessed in light of their intensity, duration and side-effects, seeking where appropriate to escalate or de-escalate therapies based on likely benefits as predicted by tumor stage and tumor biology. The Panel favored several interventions that may reduce surgical morbidity, including acceptance of 2 mm margins for DCIS, the resection of residual cancer (but not baseline extent of cancer) in women undergoing neoadjuvant therapy, acceptance of sentinel node biopsy following neoadjuvant treatment of many patients, and the preference for neoadjuvant therapy in HER2 positive and triple-negative, stage II and III breast cancer. The Panel favored escalating radiation therapy with regional nodal irradiation in high-risk patients, while encouraging omission of boost in low-risk patients. The Panel endorsed gene expression signatures that permit avoidance of chemotherapy in many patients with ER positive breast cancer. For women with higher risk tumors, the Panel escalated recommendations for adjuvant endocrine treatment to include ovarian suppression in premenopausal women, and extended therapy for postmenopausal women. However, low-risk patients can avoid these treatments. Finally, the Panel recommended bisphosphonate use in postmenopausal women to prevent breast cancer recurrence. The Panel recognized that recommendations are not intended for all patients, but rather to address the clinical needs of the majority of common presentations. Individualization of adjuvant therapy means adjusting to the tumor characteristics, patient comorbidities and preferences, and managing constraints of treatment cost and access that may affect care in both the developed and developing world.

Functional ecdysone receptor is the product of EcR and Ultraspiracle genes

Although the biological activity of the insect moulting hormone ecdysone, is manifested through a hormonally regulated transcriptional cascade associated with chromosomal puffing, a direct association of the receptor with the puff has yet to be established. The cloned ecdysone receptor (EcR) is by itself incapable of high-affinity DNA binding or transcriptional activation. Rather, these activities are dependent on heterodimer formation with Ultraspiracle (USP) the insect homologue of vertebrate retinoid X receptor. Here we report that native EcR and USP are co-localized on ecdysone-responsive loci of polytene chromosomes. Moreover, we show that natural ecdysones selectively promote physical association between EcR and USP, and conversely, that high-affinity hormone binding requires both EcR and USP. Replacement of USP with retinoid X receptor produces heterodimers with distinct pharmacological and functional properties. These results redefine the ecdysone receptor as a dynamic complex whose activity may be altered by combinatorial interactions among subunits and ligand.

Directional guidance of neuronal migration in the olfactory system by the protein Slit

Although cell migration is crucial for neural development, molecular mechanisms guiding neuronal migration have remained unclear. Here we report that the secreted protein Slit repels neuronal precursors migrating from the anterior subventricular zone in the telencephalon to the olfactory bulb. Our results provide a direct demonstration of a molecular cue whose concentration gradient guides the direction of migrating neurons. They also support a common guidance mechanism for axon projection and neuronal migration and suggest that Slit may provide a molecular tool with potential therapeutic applications in controlling and directing cell migration.

Acute motor axonal neuropathy: a frequent cause of acute flaccid paralysis in China

In northern China, annual epidemics of acute-onset flaccid paralysis diagnosed clinically as Guillain-Barré syndrome have been recognized for at least 20 years. On the basis of an historical analysis of more than 3,200 patients, distinctive features include most cases occurring during the summer months among children and young adults, most of whom reside in rural areas. Of 90 patients with acute flaccid paralysis, 88 had a distinctive pattern that shares clinical and cerebrospinal fluid findings with demyelinating Guillain-Barré syndrome, but that differs from Guillain-Barré syndrome physiologically and pathologically. The clinical course is marked by rapidly progressive ascending tetraparesis, often with respiratory failure, but without fever, systemic illness, or sensory involvement. Cerebrospinal fluid is acellular, and elevations of protein content occur in the second or third week of illness. Electrodiagnostic studies show normal motor distal latencies and limb conduction velocities, but reduced compound muscle action potential amplitudes. Sensory nerve action potentials and, when elicitable, F waves are within the range of normal. Recovery is usually good. Autopsy studies have shown Wallerian-like degeneration of motor fibers. These studies establish that this is a distinctive syndrome, distinguishable from poliomyelitis and demyelinating Guillain-Barré syndrome.

P504S: a new molecular marker for the detection of prostate carcinoma

The ability to diagnose prostate carcinoma would be improved by the detection of a tumor-associated antigen. P504S, a cytoplasmic protein, was recently identified by cDNA library subtraction in conjunction with high throughput microarray screening from prostate carcinoma. The aim of this study was to establish the pattern of expression of P504S in prostate carcinoma and benign prostatic tissue. A total of 207 cases, including 137 cases of prostate carcinoma and 70 cases of benign prostate, from prostatectomies (n = 77), prostate needle biopsies (n = 112), and transurethral prostate resections (n = 18) were examined by immunocytochemistry for P504S. P504S showed strong cytoplasmic granular staining in 100% of prostate carcinomas regardless of Gleason scores and diffuse (>75% of tumor) staining in 92% of cases. In contrast, 171 of 194 (88%) of benign prostates, including 56 of 67 (84%) benign prostate cases and 115 of 127 (91%) cases of benign glands adjacent to cancers were negative for P504S. The remainders of benign prostates were focally and weakly positive for P504S. The staining pattern of these normal glands was different and easily distinguishable from that observed in prostate carcinoma. Expression of P504S was not found in basal cell hyperplasia, urothelial cells/metaplasia and small atrophic glands that may mimic prostate carcinoma. Our findings indicate that P504S is a highly sensitive and specific positive marker for prostate carcinoma.

pRb controls proliferation, differentiation, and death of skeletal muscle cells and other lineages during embryogenesis

Mice deficient for the RB gene (RB-/-), prior to death at embryonic day 14.5, show increased cell death in all tissues that normally express RB1: the nervous system, liver, lens, and skeletal muscle precursor cells. We have generated transgenic mice (RBlox) that express low levels of pRb, driven by an RB1 minigene. RBlox/RB-/- mutant fetuses die at birth with specific skeletal muscle defects, including increased cell death prior to myoblast fusion, shorter myotubes with fewer myofibrils, reduced muscle fibers, accumulation of elongated nuclei that actively synthesized DNA within the myotubes, and reduction in expression of the late muscle-specific genes MCK and MRF4. Thus, insufficient pRb results in failure of myogenesis in vivo, manifest in two ways. First, the massive apoptosis of myoblasts implicates a role of pRb in cell survival. Second, surviving myotubes failed to develop normally and accumulated large polyploid nuclei, implicating pRb in permanent withdrawal from the cell cycle. These results demonstrate a role for pRb during terminal differentiation of skeletal muscles in vivo and place pRb at a nodal point that controls cell proliferation, differentiation, and death.

Board-invited review: the biology and regulation of preadipocytes and adipocytes in meat animals

The quality and value of the carcass in domestic meat animals are reflected in its protein and fat content. Preadipocytes and adipocytes are important in establishing the overall fatness of a carcass, as well as being the main contributors to the marbling component needed for consumer preference of meat products. Although some fat accumulation is essential, any excess fat that is deposited into adipose depots other than the marbling fraction is energetically unfavorable and reduces efficiency of production. Hence, this review is focused on current knowledge about the biology and regulation of the important cells of adipose tissue: preadipocytes and adipocytes.

Schistosomiasis in the People's Republic of China: prospects and challenges for the 21st century

Schistosomiasis japonica is a serious communicable disease and a major disease risk for more than 30 million people living in the tropical and subtropical zones of China. Infection remains a major public health concern despite 45 years of intensive control efforts. It is estimated that 865,000 people and 100,250 bovines are today infected in the provinces where the disease is endemic, and its transmission continues. Unlike the other schistosome species known to infect humans, the oriental schistosome, Schistosoma japonicum, is a true zoonotic organism, with a range of mammalian reservoirs, making control efforts extremely difficult. Clinical features of schistosomiasis range from fever, headache, and lethargy to severe fibro-obstructive pathology leading to portal hypertension, ascites, and hepatosplenomegaly, which can cause premature death. Infected children are stunted and have cognitive defects impairing memory and learning ability. Current control programs are heavily based on community chemotherapy with a single dose of the drug praziquantel, but vaccines (for use in bovines and humans) in combination with other control strategies are needed to make elimination of the disease possible. In this article, we provide an overview of the biology, epidemiology, clinical features, and prospects for control of oriental schistosomiasis in the People's Republic of China.

Dendritic L-type calcium currents in mouse spinal motoneurons: implications for bistability

The intrinsic properties of mammalian spinal motoneurons provide them with the capability to produce high rates of sustained firing in response to transient inputs (bistability). Even though it has been suggested that a persistent dendritic calcium current is responsible for the depolarizing drive underlying this firing property, such a current has not been demonstrated in these cells. In this study, calcium currents are recorded from functionally mature mouse spinal motoneurons using somatic whole-cell patch-clamp techniques. Under these conditions a component of the current demonstrated kinetics consistent with a current originating at a site spatially segregated from the soma. In response to step commands this component was seen as a late-onset, low amplitude persistent current whilst in response to depolarizing-repolarizing ramp commands a low voltage clockwise current hysteresis was recorded. Simulations using a neuromorphic motoneuron model could reproduce these currents only if a noninactivating calcium conductance was placed in the dendritic compartments. Pharmacological studies demonstrated that both the late-onset and hysteretic currents demonstrated sensitivity to both dihydropyridines and the L-channel activator FPL-64176. Furthermore, the alpha1D subunits of L-type calcium channels were immunohistochemically demonstrated on motoneuronal dendrites. It is concluded that there are dendritically located L-type channels in mammalian motoneurons capable of mediating a persistent depolarizing drive to the soma and which probably mediate the bistable behaviour of these cells.

A calcium switch for the functional coupling between alpha (hslo) and beta subunits (KV,Ca beta) of maxi K channels

KV,Ca beta subunit dramatically increases the apparent calcium sensitivity of the alpha subunit of MaxiK channels when probed in the micromolar [Ca2+]i range. Analysis in a wide range of [Ca2+]i revealed that this functional coupling is exquisitely modulated by [Ca2+]i. Ca2+ ions switch MaxiK alpha+beta complex into a functionally coupled state at concentrations beyond resting [Ca2+]i. At [Ca2+] < or = 100 nM, MaxiK activity becomes independent of Ca2+, is purely voltage-activated, and its functional coupling with its beta subunit is released. The functional switch develops at [Ca2+]i that occur during cellular excitation, providing the molecular basis of how MaxiK channels regulate smooth muscle excitability and neurotransmitter release.

Mixed-backbone oligonucleotides as second generation antisense oligonucleotides: in vitro and in vivo studies

Antisense oligonucleotides are being evaluated in clinical trials as novel therapeutic agents. To further improve the properties of antisense oligonucleotides, we have designed mixed-backbone oligonucleotides (MBOs) that contain phosphorothioate segments at the 3' and 5' ends and have a modified oligodeoxynucleotide or oligoribonucleotide segment located in the central portion of the oligonucleotide. Some of these MBOs indicate improved properties compared with phosphorothioate oligodeoxynucleotides with respect to affinity to RNA, RNase H activation, and anti-HIV activity. In addition, more acceptable pharmacological, in vivo degradation and pharmacokinetic profiles were obtained with these MBOs.

An in vitro functionally mature mouse spinal cord preparation for the study of spinal motor networks

An in vitro isolated whole spinal cord preparation has been developed in 'motor functionally mature' mice; that is mice of developmental maturity sufficient to weight-bear and walk. In balb/c mice this stage occurs at around postnatal day 10 (P10). Administration of strychnine elicited synchronous activity bilaterally in lumbar ventral roots. Rhythmic alternating locomotor-like activity could be produced by application of a combination of serotonin (5-HT), N-methyl-d-aspartate (NMDA), and dopamine in animals up to P12. Using a live cell-dead cell assay, it is demonstrated that there are primarily viable cells throughout the lumbar spinal cord. The viability of descending pathways was demonstrated with stimulation of the mid-thoracic white matter tracts. In addition, polysynaptic segmental reflexes could be elicited. Although usually absent in whole cord preparations, monosynaptic reflexes could invariably be elicited following longitudinal midline hemisection, leading to the possible explanation that there might be an active crossed pathway producing presynaptic inhibition of primary afferent terminals. The data demonstrate that this functionally mature spinal cord preparation can be used for the study of spinal cord physiology including locomotion.

Turning carbon dioxide into fuel

Our present dependence on fossil fuels means that, as our demand for energy inevitably increases, so do emissions of greenhouse gases, most notably carbon dioxide (CO2). To avoid the obvious consequences on climate change, the concentration of such greenhouse gases in the atmosphere must be stabilized. But, as populations grow and economies develop, future demands now ensure that energy will be one of the defining issues of this century. This unique set of (coupled) challenges also means that science and engineering have a unique opportunity-and a burgeoning challenge-to apply their understanding to provide sustainable energy solutions. Integrated carbon capture and subsequent sequestration is generally advanced as the most promising option to tackle greenhouse gases in the short to medium term. Here, we provide a brief overview of an alternative mid- to long-term option, namely, the capture and conversion of CO2, to produce sustainable, synthetic hydrocarbon or carbonaceous fuels, most notably for transportation purposes. Basically, the approach centres on the concept of the large-scale re-use of CO2 released by human activity to produce synthetic fuels, and how this challenging approach could assume an important role in tackling the issue of global CO2 emissions. We highlight three possible strategies involving CO2 conversion by physico-chemical approaches: sustainable (or renewable) synthetic methanol, syngas production derived from flue gases from coal-, gas- or oil-fired electric power stations, and photochemical production of synthetic fuels. The use of CO2 to synthesize commodity chemicals is covered elsewhere (Arakawa et al. 2001 Chem. Rev. 101, 953-996); this review is focused on the possibilities for the conversion of CO2 to fuels. Although these three prototypical areas differ in their ultimate applications, the underpinning thermodynamic considerations centre on the conversion-and hence the utilization-of CO2. Here, we hope to illustrate that advances in the science and engineering of materials are critical for these new energy technologies, and specific examples are given for all three examples. With sufficient advances, and institutional and political support, such scientific and technological innovations could help to regulate/stabilize the CO2 levels in the atmosphere and thereby extend the use of fossil-fuel-derived feedstocks.

Clinical and electrophysiological aspects of acute paralytic disease of children and young adults in northern China

Acute peripheral nervous system diseases leading to paralysis in children are rare in Europe and the USA, whereas epidemics of a Guillain-Barré-like syndrome occur annually among children in rural parts of northern China. To clarify the features of this disorder 36 patients, aged 15 months to 37 years (median 7) with this syndrome were investigated; 91% were from rural areas. In 47%, a prodromal illness was reported in the preceding 4 weeks. Leg weakness and resistance to neck flexion were the earliest symptoms. The weakness ascended rapidly and symmetrically to affect the arms and respiratory muscles, with maximum weakness occurring a mean of 6 days after onset of weakness. Bulbar weakness occurred in 61% of patients, but only 1 had extraocular paresis. Respiratory assistance was needed by 31% of patients. Tendon reflexes were lost as weakness developed. 42% of patients had raised concentrations of protein in the cerebrospinal fluid, and the mean cell count was 3 cells/microliters (range 0-12/microliters). Electrodiagnostic studies in 22 patients showed severe reductions in motor evoked amplitudes from distal stimulation. Sensory action potentials were normal. Electromyography revealed denervation potentials in limb muscles. The distinctive epidemiological, clinical, and neurophysiological characteristics of this illness suggest that the disorder is different from both Guillain-Barré syndrome and poliomyelitis. The neurophysiological findings support the hypothesis that the disorder is a reversible distal motor nerve terminal or anterior horn cell lesion.

Image-guided insertion of transpedicular screws. A laboratory set-up

STUDY DESIGN

A computer-assisted system allowing precise preoperative planning and real-time intraoperative image localization of surgical instruments is tested in a laboratory setup.

OBJECTIVES

The purpose of this study is to assess the applicability, functionality, and accuracy of this transpedicular spinal fixation technique.

SUMMARY OF BACKGROUND DATA

Most techniques in transpedicular spinal fixation rely on the identification of predefined targets with the help of anatomic landmarks and on the intraoperative use of image intensifiers. Various studies report considerable screw misplacement rates which may lead to serious clinical sequelae such as permanent nerve damage.

METHODS

The proposed system was tested in an in vitro setup drilling 20 pedicle pilot holes in lumbar vertebrae. The accuracy was assessed using precision cuts through the pedicles and simulation of a 6-mm pedicle screw insertion.

RESULTS

An ideal screw position was found in 70 of 77 cuts, and in no case was an injury to the pedicular cortex observed.

CONCLUSIONS

The presented technique provides a safe, accurate, and flexible basis for transpedicular screw placement in the spine. This approach should be further evaluated in clinical applications.

Coordinated movement of RACK1 with activated betaIIPKC

Protein kinase C (PKC) isozymes move upon activation from one intracellular site to another. PKC-binding proteins, such as receptors for activated C kinase (RACKs), play an important role in regulating the localization and diverse functions of PKC isozymes. RACK1, the receptor for activated betaIIPKC, determines the localization and functional activity of betaIIPKC. However, the mechanism by which RACK1 localizes activated betaIIPKC is not known. Here, we provide evidence that the intracellular localization of RACK1 changes in response to PKC activation. In Chinese hamster ovary cells transfected with the dopamine D2L receptor and in NG108-15 cells, PKC activation by either phorbol ester or a dopamine D2 receptor agonist caused the movement of RACK1. Moreover, PKC activation resulted in the in situ association and movement of RACK1 and betaIIPKC to the same intracellular sites. Time course studies indicate that PKC activation induces the association of the two proteins prior to their co-movement. We further show that association of RACK1 and betaIIPKC is required for the movement of both proteins. Our results suggest that RACK1 is a PKC shuttling protein that moves betaIIPKC from one intracellular site to another.

High frequencies of activated B cells and T follicular helper cells are correlated with disease activity in patients with new-onset rheumatoid arthritis

This study aimed to examine the frequency of different subsets of circulating B and T follicular helper (Tfh) cells in patients with new-onset rheumatoid arthritis (RA) and following standard therapies. Twenty-five RA patients and 15 healthy controls (HC) were recruited for characterizing the frequency of CD27⁺, immunoglobulin (Ig)D⁺, CD86⁺, CD95⁺, Toll-like receptor (TLR)-9⁺ B cells and inducible T cell co-stimulator (ICOS) and programmed death 1 (PD-1)-positive Tfh cells and the level of serum interleukin (IL)-21. The potential correlation between the frequency of different subsets of B and Tfh cells and the values of clinical measures in RA patients was analysed. In comparison with HC, significantly higher percentages of circulating IgD⁺ CD27⁻ CD19⁺ naive B, CD86⁺ CD19⁺ and CD95⁺ CD19⁺ activated B, CD3⁺ CD4⁺ CXCR5⁺, CD3⁺ CD4⁺ CXCR5⁺ ICOS⁺, CD3⁺ CD4⁺ CXCR5⁺ PD-1⁺ and CD3⁺ CD4⁺ CXCR5⁺ ICOS⁺ PD-1⁺ Tfh cells but lower IgD⁺ CD27⁺ CD19⁺ preswitch memory B cells were detected, accompanied by significantly higher levels of serum IL-21 in the RA patients. Furthermore, the percentages of CD95⁺ B cells were correlated positively with the frequency of PD-1⁺ Tfh cells, but negatively with ICOS⁺ Tfh cells. The percentages of CD86⁺ B cells and ICOS⁺ Tfh cells were correlated positively with the values of disease activity score 28 (DAS28). Following the drug therapies for 1 month, the percentages of CD86⁺ B and PD-1⁺ Tfh cells were reduced significantly in the drug-responding patients. Our data suggest that activated B and Tfh cells may contribute to the pathogenesis of RA and the frequency of activated B and Tfh cells may be used as biomarkers for evaluating the therapeutic responses of individual patients with RA.

Effect of different chemically modified oligodeoxynucleotides on immune stimulation

Based on previous studies that certain oligonucleotides can stimulate cell proliferation and immunoglobulin production, this study was carried out to establish the relationship between the stimulatory effect and the chemical modification of the oligonucleotide. First, the effects of oligonucleotide and analogs on immune stimulation were studied in vitro using murine splenic lymphocytes. Our results show that cell proliferation and immunoglobulin production (IgG and IgM) depend on the sequence and the chemical modification of the oligonucleotide. Phosphorothioate oligodeoxynucleotides displayed a greater stimulatory effect than partially modified phosphorothioate oligonucleotides. Second, we studied the effects of these chemically modified oligonucleotides after injection in mice. Massive splenomegaly and stimulation of cell proliferation were observed with some phosphorothioate oligonucleotides. These effects were minimized markedly by chimeric and hybrid oligonucleotides. We also demonstrate that in vitro the effects of oligonucleotides on murine lymphocytes were unaffected by T cell depletion, suggesting that oligonucleotides exert their effects mainly on the B cells.

IL-1-induced NFkappa B and c-Jun N-terminal kinase (JNK) activation diverge at IL-1 receptor-associated kinase (IRAK)

Mutant I1A cells, lacking IL-1 receptor-associated kinase (IRAK) mRNA and protein, have been used to study the involvement of IRAK in NFkappaB and c-Jun N-terminal kinase (JNK) activation. A series of IRAK deletion constructs were expressed in I1A cells, which were then tested for their ability to respond to IL-1. Both the N-terminal death domain and the C-terminal region of IRAK are required for IL-1-induced NFkappaB and JNK activation, whereas the N-proximal undetermined domain is required for the activation of NFkappaB but not JNK. The phosphorylation and ubiquitination of IRAK deletion mutants correlate tightly with their ability to activate NFkappaB in response to IL-1, but IRAK can mediate IL-1-induced JNK activation without being phosphorylated. These studies reveal that the IL-1-induced signaling pathways leading to NFkappaB and JNK activation diverge either at IRAK or at a point nearer to the receptor.

Human and rodent MaxiK channel beta-subunit genes: cloning and characterization

Voltage- and Ca2+-sensitive K+ (MaxiK) channels play key roles in controlling neuronal excitability and vascular tone. We cloned and analyzed human and rodent genes for the modulatory beta subunit, KCNMB1. The human and mouse beta-subunit genes are approximately 11 and approximately 9 kb in length, respectively, and have a four exon-three intron structure. Primer extension assay localized the transcription initiation site at 442 (human) or 440 (mouse) bp upstream of the translation initiation codon, agreeing with the transcript size in Northern blots. Both genes have a TATA-less putative promoter region, with a transcription initiator-like region, and motifs characteristic of regulated promoters, including muscle-specific enhancing factors-1 and -2. Consistent with a tissue-specific expression of KCNMB1, regulated at the transcriptional level, beta-subunit transcripts are abundant in smooth muscle and heart, but scarce in lymphatic tissues, brain, and liver. Expressed rat and mouse beta subunits increase the apparent Ca2+ sensitivity of the human MaxiK channel alpha subunit.

Bacterial photoreceptor with similarity to photoactive yellow protein and plant phytochromes

A phytochrome-like protein called Ppr was discovered in the purple photosynthetic bacterium Rhodospirillum centenum. Ppr has a photoactive yellow protein (PYP) amino-terminal domain, a central domain with similarity to phytochrome, and a carboxyl-terminal histidine kinase domain. Reconstitution experiments demonstrate that Ppr covalently attaches the blue light-absorbing chromophore p-hydroxycinnamic acid and that it has a photocycle that is spectrally similar to, but kinetically slower than, that of PYP. Ppr also regulates chalcone synthase gene expression in response to blue light with autophosphorylation inhibited in vitro by blue light. Phylogenetic analysis demonstrates that R. centenum Ppr may be ancestral to cyanobacterial and plant phytochromes.