Semiempirical QM/MM calculations reveal a step-wise proton transfer and an unusual thiolate pocket in the mechanism of the unique arylpropionate racemase AMDase G74C

Semiempirical calculations on the mechanism of the arylpropionate racemase AMDase G74C reveal a step-wise mechanism involving a planar-enedionate intermediate.

Seasonal changes in gene expression of corticoid receptors in anadromous and non-anadromous strains of rainbow trout Oncorhynchus mykiss

To clarify the regulation of expression of corticoid receptor (CR) genes during period of parr-smolt transformation of salmonids, seasonal changes in mRNA levels of glucocorticoid receptor (GR)-1, GR-2 and mineralocorticoid receptor (MR) were examined in gill, leucocytes, spleen and brain of anadromous and non-anadromous forms of Oncorhynchus mykiss. Increases in gill Na(+) , K(+) ATPase activity, plasma thyroxine levels and hypo-osmoregulatory ability assessed by 24 h seawater challenge test represented characteristics of smoltification in anadromous O. mykiss from May to June, whereas there was no apparent increase in the values of non-anadromous O. mykiss. Plasma cortisol levels of anadromous O. mykiss were higher than levels of non-anadromous O. mykiss from April to June. In gill of non-anadromous O. mykiss, there were significant increases in mRNA levels of three types of CR in spring. Although there were significant seasonal variations of CR mRNA levels in gill of anadromous O. mykiss, they appear to be less clear than those variations in non-anadromous O. mykiss. In anadromous O. mykiss, significant elevations in mRNA levels of the three types of CR were observed especially in the spleen. In both preoptic area and basal hypothalamus of the brain, there were tendencies to increase in CR mRNA levels from spring to summer in both anadromous and non-anadromous O. mykiss. These results showed difference in regulation of CR gene expression between the two forms of O. mykiss for osmoregulatory, immune and central nervous systems.

[Ultrasonography in Large-Vessel Arteritis]

Vasculitides are a group of diseases in which inflammation occurs in various vascular walls of the whole body, and ischemic symptoms are caused by stenoses and occlusions of blood vessels. Various parts of blood vessels of the whole body are affected, and the clinical manifestations are diverse. In the Chapel Hill Consensus Conference (CHCC) 2012, vasculitides are classified into seven categories. Takayasu arteritis and giant cell arteritis are included in large-vessel vasculitis. Large-vessel arteritis is defined as vasculitis affecting the aorta and its major branches more often than other vasculitides, but any sized artery may be affected. Ultrasonography has been progressing rapidly, so we can easily depict vessels of the surface of the body, in 0.1-mm units, and indicate the blood flow noninvasively. Ultrasonography has been used for the diagnosis of and estimation of the treatment for large-vessel vasculitis, and its importance has been increasing.

Valley-dependent spin polarization in bulk MoS2 with broken inversion symmetry

The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide--MoS2--using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.

Living-donor kidney transplant in T-cell and B-cell flow cytometry crossmatch-positive patients

OBJECTIVES

Complement-dependent cytotoxic crossmatch is an important indicator for kidney transplant. However, there is controversy about treatment for flow cytometry crossmatch-positive cases.

MATERIALS AND METHODS

This was a retrospective study of 127 living-donor kidney transplant recipients from May 2007 to July 2011. We divided patients into 115 flow cytometry crossmatch T-cell and B-cell-negative cases, and 12 T-cell and B-cell-positive cases. Both groups were given 20 mg basiliximab the day of surgery and 4 days after surgery. Common oral immunosuppressive agents used were tacrolimus, mycophenolate mofetil, and methylprednisolone. Flow cytometry crossmatch T-cell and B-cell-negative recipients started immunosuppression 7 days before surgery, T-cell and B-cell-positive recipients started immunosuppression 14 days before surgery. T-cell and B-cell-positive patients also received 200 mg rituximab 1 week before surgery, had 3 plasma exchange sessions before transplant, and received intravenous immunoglobulin 20 g/day during surgery and after surgery for 5 days. We measured flow-panel reactive antibodies of T-cell and B-cell-positive patients just before surgery to check desensitization efficiency. We evaluated patient survival, graft survival, graft function, and frequency of rejection and infectious diseases.

RESULTS

Patient survival and graft survival were 100% in both groups. Flow cytometry crossmatch T-cell and B-cell-positive cases had no rejection events, but T-cell and B-cell-negative groups developed rejection. There was no statistical difference in the incidence of infection and graft function. Flow-panel reactive antibody demonstrated improvement in all T-cell and B-cell-positive cases.

CONCLUSIONS

In living-donor kidney transplant, flow cytometry crossmatch T-cell and B-cell-positive patients are still considered to be at high risk. Although this is a short-term outcome, all T-cell and B-cell-positive patients in this study achieved excellent results with appropriate preoperative and postoperative treatment.

Photoelectron spin-polarization control in the topological insulator Bi2Se3

We study the manipulation of the spin polarization of photoemitted electrons in Bi2Se3 by spin- and angle-resolved photoemission spectroscopy. General rules are established that enable controlling the photoelectron spin-polarization. We demonstrate the ± 100% reversal of a single component of the measured spin-polarization vector upon the rotation of light polarization, as well as full three-dimensional manipulation by varying experimental configuration and photon energy. While a material-specific density-functional theory analysis is needed for the quantitative description, a minimal yet fully generalized two-atomic-layer model qualitatively accounts for the spin response based on the interplay of optical selection rules, photoelectron interference, and topological surface-state complex structure. It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture.

Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result.

Kinetic modeling of particle dynamics in H(-) negative ion sources (invited)

Progress in the kinetic modeling of particle dynamics in H(-) negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H(-) ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H(-) production, and (ii) extraction physics of H(-) ions and beam optics.

Quantification and visualization of cellular NAD(P)H in young and aged female facial skin with in vivo two-photon tomography

BACKGROUND

In vivo two-photon tomography is a novel noninvasive three-dimensional optical skin imaging technology with subcellular resolution which enables the sensitive detection of endogenous fluorophores. One of these fluorophores, NAD(P)H (a coenzyme which plays an important role in the release of free energy during glycolysis, and influences filaggrin and lipid synthesis), can be selectively detected in keratinocytes (granular cells) with two-photon tomography.

OBJECTIVES

To quantify NAD(P)H levels in subsurface human facial skin in vivo as a measure to determine if there are changes with age.

METHODS

A total of 80 healthy Asian females were enrolled in this study, aged 21-68 years. Measurements were performed on facial skin using in vivo two-photon tomography (DermaInspect/MPTflex™, JenLab GmbH, Jena, Germany). The laser beam scans a skin field of interest in pulses, focused at a depth to reach the granular layer. The near-infrared laser pulses excite the endogenous fluorophores NAD(P)H. Image processing was performed to obtain high-resolution autofluorescence images (optical biopsies) and to quantify the fluorescent grey scale to determine NAD(P)H levels. Additional skin surface measures taken were hydration (corneometer), elasticity (cutometer) and wrinkles (image capture and analysis).

RESULTS

Statistically significant changes in all measured parameters as a function of age were observed. Most importantly, the mean fluorescent grey scale values for NAD(P)H in the youngest group studied (women in their 20s) was 38.8 (SD ± 12.39), while that of the oldest group studied (women in their 60s) was 32.7 (SD ± 12.47). These NAD(P)H levels are statistically significantly different (P = 0.0078).

CONCLUSIONS

The level of NAD(P)H in the epidermis is significantly greater in younger vs. older skin in vivo. This likely reflects decreased production and/or increased degradation of NAD(P)H in older skin, possibly as a result of chronological ageing and environmental damage (e.g. photodamage). NAD(P)H levels in epidermal skin may be a useful biomarker of skin ageing in vivo. It is also likely that maintaining NAD(P)H production is a useful approach to maintaining good skin condition and caring for ageing skin.

Close relationships between polar auxin transport and graviresponse in plants

Gravitational force on Earth is one of the major environmental factors affecting plant growth and development. Spacecraft and the International Space Station (ISS), and a three-dimensional (3-D) clinostat have been available to clarify the effects of gravistimulation on plant growth and development in space and on ground conditions, respectively. Under a stimulus-free environment such as space conditions, plants show a growth and developmental habit designated as 'automorphosis' or 'automorphogenesis'. Recent studies in hormonal physiology, together with space and molecular biology, have demonstrated the close relationships between automorphosis and polar auxin transport. Reduced polar auxin transport in space conditions, or induced by the application of polar auxin transport inhibitors, substantially induced automorphosis or automorphosis-like growth and development, indicating that polar auxin transport is responsible for graviresponse in plants. This concise review covers graviresponse in plants and automorphosis observed in space conditions, and polar auxin transport related to graviresponse in etiolated Alaska and ageotropum pea seedlings. Molecular aspects of polar auxin transport clarified in recent studies are also described.

Impact of flow cytometry crossmatch B-cell positivity on living renal transplantation

BACKGROUND

Various studies have reported poorer graft survival among individuals displaying T-cell-positive flow cytometry crossmatches (FCXM). Good outcomes have been observed in immunologically high-risk patients with the use of rituximab, plasmapheresis, and γ-globulin. Because the relevance of FCXM B-cell-positivity (BCXM (+)) alone remains controversial, we examined its impact on living donor renal transplantations.

PATIENTS AND METHODS

We retrospectively studied 146 adult renal transplantation recipients from April 2007 to June 2012, dividing the patients into BCXM (+) (n = 31) versus BCXM (-) recipients (n = 115). We examined patient and graft survivals as well as rejection rates at 0 to 3, 3 to 12, and 12 to 24 months. We also determined the incidence of infectious diseases. We performed stepwise multivariate regression to identify risk factors contributing rejection episodes.

RESULTS

One-year patient and graft survivals were 100% in both groups. The BCXM (-) group have a 16.8% rejection probability whereas the BCXM (+) group, 33.2% (P = .201). There were no significantly differences in the incidence of infectious diseases. Only the rate of a sensitizing history was an independent risk factor for a rejection episode.

CONCLUSION

BCXM (+) showed only a tendency but not a significant impact on rejection episodes compared with BCXM (-); short-term graft survivals were similar.

Neurological deterioration due to missed thoracic spinal stenosis after decompressive lumbar surgery

There have been a few reports of patients with a combination of lumbar and thoracic spinal stenosis. We describe six patients who suffered unexpected acute neurological deterioration at a mean of 7.8 days (6 to 10) after lumbar decompressive surgery. Five had progressive weakness and one had recurrent pain in the lower limbs. There was incomplete recovery following subsequent thoracic decompressive surgery.

The neurological presentation can be confusing. Patients with compressive myelopathy due to lower thoracic lesions, especially epiconus lesions (T10 to T12/L1 disc level), present with similar symptoms to those with lumbar radiculopathy or cauda equina lesions. Despite the rarity of this condition we advise that patients who undergo lumbar decompressive surgery for stenosis should have sagittal whole spine MRI studies pre-operatively to exclude proximal neurological compression.

Cite this article: Bone Joint J 2013;95-B:1388–91.

ANGPTL4 is a secreted tumor suppressor that inhibits angiogenesis

Tumor suppressors with extracellular function are likely to have advantages as targets for cancer therapy, but few are known. Here, we focused on angiopoietin-like 4 (ANGPTL4), which is a secreted glycoprotein involved in lipoprotein metabolism and angiogenesis, is methylation-silenced in human cancers, but has unclear roles in cancer development and progression. We found a deletion mutation in its coiled-coil domain at its N-terminal in human gastric cancers, in addition to hypermethylation of the ANGPTL4 promoter CpG islands. Forced expression of wild-type ANGPTL4, but not ANGPTL4 with the deletion, at physiological levels markedly suppressed in vivo tumorigenicity and tumor angiogenesis, indicating that the latter caused the former. Tumor-derived ANGPTL4 suppressed in vitro vascular tube formation and proliferation of human umbilical vascular endothelial cells, partly due to suppression of ERK signaling. These showed that ANGPTL4 is a genetically and epigenetically inactivated secreted tumor suppressor that inhibits tumor angiogenesis.

Topological surface states with persistent high spin polarization across the Dirac point in Bi2Te2Se and Bi2Se2Te

Helical spin textures with marked spin polarizations of topological surface states have been unveiled for the first time by state-of-the-art spin- and angle-resolved photoemission spectroscopy for two promising topological insulators, Bi(2)Te(2)Se and Bi(2)Se(2)Te. Their highly spin-polarized natures are found to be persistent across the Dirac point in both compounds. This novel finding paves a pathway to extending the utilization of topological surface states of these compounds for future spintronic applications.

The surgical treatment of pyogenic spondylitis using posterior instrumentation without anterior debridement

There have been few reports regarding the efficacy of posterior instrumentation alone as surgical treatment for patients with pyogenic spondylitis, thus avoiding the morbidity of anterior surgery. We report the clinical outcomes of six patients with pyogenic spondylitis treated effectively with a single-stage posterior fusion without anterior debridement at a mean follow-up of 2.8 years (2 to 5). Haematological data, including white cell count and level of C-reactive protein, returned to normal in all patients at a mean of 8.2 weeks (7 to 9) after the posterior fusion. Rigid bony fusion between the infected vertebrae was observed in five patients at a mean of 6.3 months (4.5 to 8) post-operatively, with the remaining patient having partial union. Severe back pain was immediately reduced following surgery and the activities of daily living showed a marked improvement. Methicillin-resistant Staphylococcus aureus was detected as the causative organism in four patients.

Single-stage posterior fusion may be effective in patients with pyogenic spondylitis who have relatively minor bony destruction.

Relationship between perifoveal capillaries and pathomorphology in macular oedema associated with branch retinal vein occlusion

PURPOSE

To study the relationship between macular ischaemia on fluorescein angiography (FA) and pathomorphology at the foveal centre delineated by spectral-domain optical coherence tomography (OCT) in macular oedema (MO) associated with branch retinal vein occlusion (BRVO).

METHODS

One hundred and five consecutive eyes of 105 patients with MO (centre point thickness (CPT) ≥ 300 μm) associated with BRVO in which FA using Heidelberg Retinal Angiography 2 and Spectralis OCT were performed on the same day were retrospectively reviewed. We evaluated the foveal pathomorphology using OCT images and the association with macular ischaemia.

RESULTS

Within 1 year from symptom onset, 94 eyes were classified with perfused macula (34 eyes) or non-perfused macula (60 eyes). Eyes with perfused macula had better visual acuity and less CPT than those with non-perfused macula (P=0.024 and P<0.001, respectively). Fourteen eyes with perfused macula had serous retinal detachment (SRD) alone at the presumed foveal centre (SRD type); seven, a sponge-like swelling at that area (retinal swelling type); 11, foveal cystoid spaces alone (cystoid MO (CMO) type), and 2, with both SRD and foveal cystoid spaces (SRD+CMO type). However, 58 eyes with non-perfused macula had foveal cystoid spaces (42 of CMO type and 16 of SRD+CMO type), with a significant association between them (P<0.001). Among 11 eyes with symptoms exceeding 1 year, 6 eyes had perfused macula, and none had the SRD type.

CONCLUSION

Most eyes without foveal cystoid spaces have perfused macula in MO associated with BRVO.