Characteristics of single large-conductance Ca2+-activated K+ channels and their regulation of action potentials and excitability in parasympathetic cardiac motoneurons in the nucleus ambiguus

Large-conductance Ca2(+)-activated K+ channels (BK) regulate action potential (AP) properties and excitability in many central neurons. However, the properties and functional roles of BK channels in parasympathetic cardiac motoneurons (PCMNs) in the nucleus ambiguus (NA) have not yet been well characterized. In this study, the tracer X-rhodamine-5 (and 6)-isothiocyanate (XRITC) was injected into the pericardial sac to retrogradely label PCMNs in FVB mice at postnatal 7-9 days. Two days later, XRITC-labeled PCMNs in brain stem slices were identified. Using excised patch single-channel recordings, we identified voltage-gated and Ca(2+)-dependent BK channels in PCMNs. The majority of BK channels exhibited persistent channel opening during voltage holding. These BK channels had a conductance of 237 pS and a 50% opening probability at +27.9 mV, the channel open time constant was 3.37 ms at +20 mV, and dwell time increased exponentially as the membrane potential depolarized. At the +20-mV holding potential, the [Ca2+]50 was 15.2 μM with a P0.5 of 0.4. Occasionally, some BK channels showed a transient channel opening and fast inactivation. Using whole cell voltage clamp, we found that BK channel mediated outward currents and afterhyperpolarization currents (IAHP). Using whole cell current clamp, we found that application of BK channel blocker iberiotoxin (IBTX) increased spike half-width and suppressed fast afterhyperpolarization (fAHP) amplitude following single APs. In addition, IBTX application increased spike half-width and reduced the spike frequency-dependent AP broadening in trains and spike frequency adaption (SFA). Furthermore, BK channel blockade decreased spike frequency. Collectively, these results demonstrate that PCMNs have BK channels that significantly regulate AP repolarization, fAHP, SFA, and spike frequency. We conclude that activation of BK channels underlies one of the mechanisms for facilitation of PCMN excitability.

[Transaxillary concealing single incision endoscopic thoracic sympathectomy in the treatment of palmar hyperhidrosis: a novel surgical approach]

OBJECTIVE

To evaluate the cosmetic effect and safety of transaxillary concealing single incision endoscopic thoracic sympathectomy in the treatment of palmar hyperhidrosis (PH).

METHODS

Retrospective study was conducted for 326 PH cases undergoing transaxillary concealing single incision endoscopic thoracic bilateral sympathectomy during January 2009 and March 2011.

RESULTS

All operations were successfully performed without severe complication and mortality. No conversion into open technique was necessary. The mean unilateral operative duration was 5.8 (5-8) min. It was calculated from the time of skin incision to the application of dressing over wound. The mean follow-up period was 25 (8-38) months. All patients achieved excellent cosmetic effects with undetectable incision.

CONCLUSION

Transaxillary concealing single incision endoscopic thoracic sympathectomy is a safe and effective procedure for treating primary PH. Incision is undetectable with excellent cosmetic effect. It is worthy of wider popularization.

Enhancement of Cerenkov luminescence imaging by dual excitation of Er(3+),Yb(3+)-doped rare-earth microparticles

Cerenkov luminescence imaging (CLI) has been successfully utilized in various fields of preclinical studies; however, CLI is challenging due to its weak luminescent intensity and insufficient penetration capability. Here, we report the design and synthesis of a type of rare-earth microparticles (REMPs), which can be dually excited by Cerenkov luminescence (CL) resulting from the decay of radionuclides to enhance CLI in terms of intensity and penetration.

METHODS

Yb(3+)- and Er(3+)- codoped hexagonal NaYF4 hollow microtubes were synthesized via a hydrothermal route. The phase, morphology, and emission spectrum were confirmed for these REMPs by power X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectrophotometry, respectively. A commercial CCD camera equipped with a series of optical filters was employed to quantify the intensity and spectrum of CLI from radionuclides. The enhancement of penetration was investigated by imaging studies of nylon phantoms and nude mouse pseudotumor models.

RESULTS

the REMPs could be dually excited by CL at the wavelengths of 520 and 980 nm, and the emission peaks overlaid at 660 nm. This strategy approximately doubled the overall detectable intensity of CLI and extended its maximum penetration in nylon phantoms from 5 to 15 mm. The penetration study in living animals yielded similar results.

CONCLUSIONS

this study demonstrated that CL can dually excite REMPs and that the overlaid emissions in the range of 660 nm could significantly enhance the penetration and intensity of CL. The proposed enhanced CLI strategy may have promising applications in the future.

Sphingobacterium arenae sp. nov., isolated from sandy soil

A novel, Gram-stain-negative, non-motile, non-spore-forming, short rod-shaped, aerobic bacterium designated H-12(T) was isolated from a mixed sandy soil sample collected from Xinjiang, China. Strain H-12(T) grew at 20-37 °C (optimum, 30 °C), pH 7.0-11.0 (optimum, pH 8.5) on TGY medium with 0-5 % NaCl (w/v). 16S rRNA gene sequence analysis indicated that strain H-12(T) shared sequence similarities with Sphingobacterium composti DSM 18850(T) (90.0 %). Strain H-12(T) showed a low level of DNA-DNA relatedness to Sphingobacterium composti DSM 18850(T) (45.5 %). The predominant isoprenoid quinone of strain H-12(T) was MK-7 and the major polar lipid was phosphatidylethanolamine. The predominant cellular fatty acids were C16:1ω7c and/or C16 : 1ω6c, iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 0, C16 : 0 3-OH and iso-C15 : 0 3-OH. DNA G+C content of strain H-12(T) was 44.15 mol%. On the basis of phenotypic, genetic and phylogenetic data, strain H-12(T) is proposed to be a representative of a novel species of the genus Sphingobacterium, for which the name Sphingobacterium arenae sp. nov. is suggested and the type strain is H-12(T) ( = ACCC 05758(T) = KCTC 32294(T)).

Evaluation of a novel thermosensitive heparin-poloxamer hydrogel for improving vascular anastomosis quality and safety in a rabbit model

Despite progress in the design of advanced surgical techniques, stenosis recurs in a large percentage of vascular anastomosis. In this study, a novel heparin-poloxamer (HP) hydrogel was designed and its effects for improving the quality and safety of vascular anastomosis were studied. HP copolymer was synthesized and its structure was confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (¹H-NMR). Hydrogels containing HP were prepared and their important characteristics related to the application in vascular anastomosis including gelation temperature, rheological behaviour and micromorphology were measured. Vascular anastomosis were performed on the right common carotid arteries of rabbits, and the in vivo efficiency and safety of HP hydrogel to achieve vascular anastomosis was verified and compared with Poloxamer 407 hydrogel and the conventional hand-sewn method using Doppler ultrasound, CT angiograms, scanning electron microscopy (SEM) and histological technique. Our results showed that HP copolymer displayed special gel-sol-gel phase transition behavior with increasing temperature from 5 to 60 °C. HP hydrogel prepared from 18 wt% HP solution had a porous sponge-like structure, with gelation temperature at approximately 38 °C and maximum elastic modulus at 10,000 Pa. In animal studies, imaging and histological examination of rabbit common jugular artery confirmed that HP hydrogel group had similar equivalent patency, flow and burst strength as Poloxamer 407 group. Moreover, HP hydrogel was superior to poloxamer 407 hydrogel and hand-sewn method for restoring the functions and epithelial structure of the broken vessel junctions after operation. By combining the advantages of heparin and poloxamer 407, HP hydrogel holds high promise for improving vascular anastomosis quality and safety.

[Spectroscopic diagnosis of dielectric barrier discharge in long gap under low presssure]

In the present paper, a dielectric barrier discharge (DBD) plasma was generated at low pressure in a DBD device with the eletrode distance of 10cm and using Ar as working gas. The changes in electronic temperature and density in the discharge cavum were studied by means of emission spectrometry. The changes in electronic temperature measured by using corona model were obtained. The variations in electronic density were analyzed using 750.4 nm line intensity. It was found that the plasma electronic temperature and density is various at different positions in the discharge cavum. With the measuring point moving from cathode to anode, the electronic temperature firstly increases slowly, then decreases quickly. While the electronic density increases slowly at first, and then rapidly.

The role of RING box protein 1 in mouse oocyte meiotic maturation

RING box protein-1 (RBX1) is an essential component of Skp1-cullin-F-box protein (SCF) E3 ubiquitin ligase and participates in diverse cellular processes by targeting various substrates for degradation. However, the physiological function of RBX1 in mouse oocyte maturation remains unknown. Here, we examined the expression, localization and function of RBX1 during mouse oocyte meiotic maturation. Immunofluorescence analysis showed that RBX1 displayed dynamic distribution during the maturation process: it localized around and migrated along with the spindle and condensed chromosomes. Rbx1 knockdown with the appropriate siRNAs led to a decreased rate of first polar body extrusion and most oocytes were arrested at metaphase I. Moreover, downregulation of Rbx1 caused accumulation of Emi1, an inhibitor of the anaphase-promoting complex/cyclosome (APC/C), which is required for mouse meiotic maturation. In addition, we found apparently increased expression of the homologue disjunction-associated protein securin and cyclin B1, which are substrates of APC/C E3 ligase and need to be degraded for meiotic progression. These results indicate the essential role of the SCF^βTrCP-EMI1-APC/C axis in mouse oocyte meiotic maturation. In conclusion, we provide evidence for the indispensable role of RBX1 in mouse oocyte meiotic maturation.

Molecular characteristics of the MHC-DRA genes from yak (Bos grunniens) and Chinese yakow (Bos grunniens × Bos taurus)

Two full-length cDNAs (762 bp) of the DRA gene from yak and Chinese yakow were isolated and analysed to identify structural and functional variations. The sequences for DRA in yak (Bogr-DRA) and Chinese yakow (Bogr × BoLA-DRA) were essentially identical to those for cattle (99%) and buffalo (97%). Except for two substitutions in the amino acids comprising the domain for signal peptide (SP) in yak, the additional residues were highly conserved across the species investigated. Peptide-binding site (PBS) of Bogr-DRA and Bogr × BoLA-DRA was highly reserved in the α1 domain among all species investigated. The lack of mutation in Bogr-DRA is consistent with the conception that the gene is highly conserved among all mammalian species. The very high conservation of the DRA gene among ruminants, including yak, may be due to its recent evolutionary detachment.

Standardization and cross validation of alloreactive IFNγ ELISPOT assays within the clinical trials in organ transplantation consortium

Emerging evidence indicates memory donor-reactive T cells are detrimental to transplant outcome and that quantifying the frequency of IFNγ-producing, donor-reactive PBMCs by ELISPOT has potential utility as an immune monitoring tool. Nonetheless, differences in assay performance among laboratories limit the ability to compare results. In an effort to standardize assays, we prepared a panel of common cellular reagent standards, developed and cross validated a standard operating procedure (SOP) for alloreactive IFNγ ELISPOT assays in several research laboratories supported by the NIH-funded Clinical Trials in Organ Transplantation (CTOT) Consortium. We demonstrate that strict adherence to the SOP and centralized data analysis results in high reproducibility with a coefficient of variance (CV) of ≈ 30%. This standardization of IFNγ ELISPOT assay will facilitate interpretation of data from multicenter transplantation research studies and provide the foundation for developing clinical laboratory testing strategies to guide therapeutic decision-making in transplant patients.

A method for detecting forward scattering signals on-chip with a photonic-microfluidic integrated device

A photonic integrated microfluidic device is demonstrated to perform optical excitation and forward scatter collection all on-chip in a planar format. Integrated on-chip optics formed a tailored beam geometry for optimal excitation of particles while a special design modification allowed for on-chip forward collection with the beam shaping capabilities. A notch was placed in the lens system that caused a dark spot on the facet of a collection waveguide while not affecting the beam geometry at the point of interrogation. The modified device with the ability to form a 10 μm beam geometry was demonstrated to detect the forward scatter from blank 5 μm diameter polystyrene beads. Free-space collection of side scatter signals was performed simultaneously with the on-chip collection and the designs demonstrated and enhanced SNR while the reliability of detection was determined to be appropriate for many applications. Excellent performance was confirmed via a false positive rate of 0.4%, a missed events rate of 6.8%, and a coincident rate of 96.3% as determined between simultaneously performed free-space and on-chip detection schemes.

Molecular epidemiological survey of hemoglobinopathies in the Wuxi region of Jiangsu Province, eastern China

In order to determine the prevalence and molecular characterization of hemoglobinopathies in the Wuxi region of Jiangsu Province in the People's Republic of China (PRC), a total of 10,297 healthy people selected from a regional hospital were screened. Hemoglobin (Hb) electrophoresis, complete blood cell (CBC) count, polymerase chain reaction (PCR), DNA sequencing, reverse dot-blot and multiplex ligation-dependent probe amplification (MLPA) were used to detect Hb variants, thalassemias and hereditary persistence of fetal Hb (HPFH). Two thousand and twenty-one adult subjects were screened for thalassemia, five cases were identified as α-thalassemia (α-thal) carriers including three cases of the -α(3.7) (rightward) deletion, one case of the - -(SEA) deletion and one case of β-thal [IVS-II-654 (C>T), (HBB: c.316-197C>T)]. The incidence of Hb variants, thalassemia and HPFH/δβ-thal were 0.136% (14/10,297), 0.25% (5/2021) and 0.0001% (1/10,297), respectively. Eight genotypes of Hb variants were found, including Hb E [β26(B8)Glu→Lys, GAG>AAG; HBB: c.79G>A], Hb J-Bangkok [β56(D7)Gly→Asp (GGC>GAC); HBB; c.170G>A], Hb G-Coushatta [β22(4)Glu→Ala (GAA>GCA); HBB: c.68A>C], Hb Queens [α34(B15)Leu→Arg (CTG>CGG) (α2 or α1); HBA2: c.104T>G (or HBA1)], Hb I [α16(A14)Lys→Glu, AAG>GAG (α1); HBA1: c.49A>G], Hb Beijing [α16(A14)Lys→Asn (AAG>AAC or AAT) (α2 or α1); HBA2: c.51G>C (or HBA1) or 51G>T (or HBA1)], Hb Ube-2 [α68(E17)Asn→Asp (AAC>GAC) (α2 or α1); HBA2: c.205A>G (or HBA1)] and Hb G-Taipei [β22(B4)Glu→Gly (GAA>GGA); HBB: c.68A>G]. A Sicilian δβ(0)-thal, identified for the first time in Asia, was also found in this survey.

Kidney transplantation from donors after brain or cardiac death in China--a clinical analysis of 94 cases

BACKGROUND

We analyzed outcomes of kidney transplantation (KTx) from donation after brain death (DBD) or cardiac death (DCD) in China under the current level of the health care system.

METHODS

Among 94 KTx performed from February 2007 to March 2012 in two organ transplant centers in the south of China, 50 KTx were used DBD and 44 DCD donors. We retrospectively analyzed the clinical outcomes.

RESULTS

At a mean follow-up of 25.5 months, the 1-year and 2-year graft survival rates were 96.8% and 95.2% respectively. Delayed graft function (DGF) occurred in 27.7% recipients, three of whom lost graft function. Among six observed acute rejection episodes, five were reversed. When compared to the DCD group in DBD patients were apt to recover from DGF. Serum creatinine decreased more promptly in the DBD than in DCD group. Serum creatinine in the DCD group increased after months 12, when it was significantly higher than that in the DBD group (P < .05).

CONCLUSIONS

Kidney transplantation from DBD donors showed good outcomes with few complications. Although KTx from DCD donors showed a higher DGF rate and longer duration of graft recovery, we achieved favorable short-term clinical outcome using this source.

Advances in the understanding of nanomaterial–biomembrane interactions and their mathematical and numerical modeling

The widespread application of nanomaterials (NMs), which has accompanied advances in nanotechnology, has increased their chances of entering an organism, for example, via the respiratory system, skin absorption or intravenous injection. Although accumulating experimental evidence has indicated the important role of NM–biomembrane interaction in these processes, the underlying mechanisms remain unclear. Computational techniques, as an alternative to experimental efforts, are effective tools to simulate complicated biological behaviors. Computer simulations can investigate NM–biomembrane interactions at the nanoscale, providing fundamental insights into dynamic processes that are challenging to experimental observation. This paper reviews the current understanding of NM–biomembrane interactions, and existing mathematical and numerical modeling methods. We highlight the advantages and limitations of each method, and also discuss the future perspectives in this field. Better understanding of NM–biomembrane interactions can benefit various fields, including nanomedicine and diagnosis.