Technique of retinal gene therapy: delivery of viral vector into the subretinal space

PurposeSafe and reproducible delivery of gene therapy vector into the subretinal space is essential for successful targeting of the retinal pigment epithelium (RPE) and photoreceptors. The success of surgery is critical for the clinical efficacy of retinal gene therapy. Iatrogenic detachment of the degenerate (often adherent) retina in patients with hereditary retinal degenerations and small volume (eg, 0.1 ml) subretinal injections pose new surgical challenges.MethodsOur subretinal gene therapy technique involved pre-operative planning with optical coherence tomography (OCT) and autofluorescence (AF) imaging, 23 G pars plana vitrectomy, internal limiting membrane staining with Membrane Blue Dual (DORC BV, Zuidland, Netherlands), a two-step subretinal injection using a 41 G Teflon tipped cannula (DORC) first with normal saline to create a parafoveal bleb followed by slow infusion of viral vector via the same self-sealing retinotomy. Surgical precision was further enhanced by intraoperative OCT (Zeiss Rescan 7000, Carl Zeiss Meditec AG, Jena, Germany). Foveal functional and structural recovery was evaluated using best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, microperimetry and OCT.ResultsTwo patients with choroideremia aged 29 (P1) and 27 (P2) years, who had normal and symmetrical levels of best-corrected visual acuity (BCVA) in both eyes, underwent unilateral gene therapy with the fellow eye acting as internal control. The surgeries were uncomplicated in both cases with successful detachment of the macula by subretinal vector injection. Both treated eyes showed recovery of BCVA (P1: 76-77 letters; P2: 84-88 letters) and mean threshold sensitivity of the central macula (P1: 10.7-10.7 dB; P2: 14.2-14.1 dB) to baseline within a month. This was accompanied by normalisation of central retinal thickness on OCT.ConclusionsHerein we describe a reliable technique for subretinal gene therapy, which is currently used in clinical trials to treat choroideremia using an adeno-associated viral (AAV) vector encoding the CHM gene. Strategies to minimise potential complications, such as avoidance of excessive retinal stretch, air bubbles within the injection system, reflux of viral vector and post-operative vitritis are discussed.

Irisin alleviates pressure overload-induced cardiac hypertrophy by inducing protective autophagy via mTOR-independent activation of the AMPK-ULK1 pathway

In hypertrophic hearts, autophagic flux insufficiency is recognized as a key pathology leading to maladaptive cardiac remodeling and heart failure. This study aimed to illuminate the cardioprotective role and mechanisms of a new myokine and adipokine, irisin, in cardiac hypertrophy and remodeling. Adult male wild-type, mouse-FNDC5 (irisin-precursor)-knockout and FNDC5 transgenic mice received 4 weeks of transverse aortic constriction (TAC) alone or combined with intraperitoneal injection of chloroquine diphosphate (CQ). Endogenous FNDC5 ablation aggravated and exogenous FNDC5 overexpression attenuated the TAC-induced hypertrophic damage in the heart, which was comparable to the protection of irisin against cardiomyocyte hypertrophy induced by angiotensin II (Ang II) or phenylephrine (PE). Accumulated autophagosome and impaired autophagy flux occurred in the TAC-treated myocardium and Ang II- or PE-insulted cardiomyocytes. Irisin deficiency caused reduced autophagy and aggravated autophagy flux failure, whereas irisin overexpression or supplementation induced protective autophagy and improved autophagy flux, which were reversed by autophagy inhibitors Atg5 siRNA, 3-MA and CQ. Irisin boosted the activity of only AMPK but not Akt and MAPK family members in hypertrophic hearts and cultured cardiomyocytes and further activated ULK1 at Ser555 but not Ser757 and did not affect the mTOR-S6K axis. Blockage of AMPK and ULK1 with compund C and SBI-0206965, respectively, both abrogated irisin's protection against cardiomyocyte hypertrophic injury and reversed its induction of both autophagy and autophagy flux. Our results suggest that irisin protects against pressure overload-induced cardiac hypertrophy by inducing protective autophagy and autophagy flux via activating AMPK-ULK1 signaling.

First-in-human study of the safety and viability of intraocular robotic surgery

Microsurgery of the retina would be dramatically improved by instruments that offer supra-human precision. Here, we report the results of a first-in-human study of remotely controlled robot-assisted retinal surgery performed through a telemanipulation device. Specifically, 12 patients requiring dissection of the epiretinal or inner limiting membrane over the macula were randomly assigned to either undergo robot-assisted-surgery or manual surgery, under general anaesthesia. We evaluated surgical success, duration of surgery and amount of retinal microtrauma as a proxy for safety. Surgical outcomes were equally successful in the robotic-surgery and manual-surgery groups. Differences in the amount of retinal microtrauma between the two groups were statistically insignificant, yet dissection took longer with robotic surgery (median time, 4 min 5 s) than with manual surgery (1 min 20 s). We also show the feasibility of using the robot to inject recombinant tissue plasminogen activator under the retina to displace sight-threatening haemorrhage in three patients under local anaesthesia. A safe and viable robotic system for intraocular surgery would enable precise and minimally traumatic delivery of gene therapy or cell therapy to the retina.

Irisin ameliorates angiotensin II-induced cardiomyocyte apoptosis through autophagy

Cardiac hypertrophy is the main cause of heart failure and sudden death in patients. But the pathogenesis is unclear. Angiotensin II may contribute to cardiac hypertrophy in response to pressure overload. In angiotensin II-treated cardiomyocytes, there is a larger cross-sectional area, more apoptosis cells, and a reduction of irisin expression. An increase in P62, an autophagy flux index, as well as LC3II, were observed in cardiomyocytes after angiotensin II-induced injury. Surprisely, irisin supplementation increased LC3II expression and decreased P62 expression, consisted of results of RFP-GFP-LC3B adenovirus transfection, and reduced cardiomyocyte apoptosis, meanwhile, the protection of irisin was reversed by the autophagy inhibitor 3-methyladenine. In animal experiments, overexpression of irisin reduced cardiomyocyte apoptosis and alleviated myocardial hypertrophy caused by pressure overload. The above results indicate that irisin-induced protective autophagy and alleviated the apoptosis signaling pathway in cardiomyocytes, consequently reducing cardiomyocyte apoptosis after angiotensin II-induced injury. Hence, increasing irisin expression may be a new way to improve cardiac function and quality of life in patients with cardiac hypertrophy.

Polymorphisms of the CYP1A1 and GSTM1 genes in relation to individual susceptibility to lung carcinoma in Chinese population

Cytochrome P450 1A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) metabolize tobacco-related carcinogens. To investigate the prevalence of CYP1A1 and GSTM1, and their association with increased risk of lung carcinoma in Chinese, allele-specific PCR and multiplex PCR technique were employed to identify the genotypes of CYP1A1 and GSTM1 in a case-control study of 106 lung carcinoma patients with histopathological diagnosis and 106 matched controls free of malignancy in Jiangsu Province, China. Logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence intervals (CI). The results showed that individuals with GSTM1 null, and the combined GSTM1 null/CYP1A1 Ile/Val or GSTM1 null/CYP1A1 Val/Val had an elevated risk of lung carcinoma, with the OR, 1.92 (P=0.02; CI, 1.07-3.46), 3.27 (P=0.01; CI, 1.23-8.84) and 9.33 (P=0.04; CI, 1.01-217.42), respectively. Light smokers (<30 pack-years) carrying GSTM1 null genotype were shown to have the increased risk to lung carcinoma (OR=3.47; CI, 1.13-7.57). Our study suggested that the null GSTM1 genotype, independently or in combined with at least one Val allele of CYP1A1, might affect the genetic susceptibility for lung carcinoma in Chinese population.

A PC-based ultrasonic data acquisition system for computer-aided prosthetic socket design

A PC-based ultrasound data acquisition system has been developed which uses compound scanning techniques to image a residual limb in a water tank. From the received ultrasonic eco data, the system produces cross-sectional images and reconstructs a three-dimensional (3-D) model of the limb. A commercial software for computer-aided prosthetic socket design was modified so that it can display both the external shape and cross-sectional image of the limb and allow the prosthetist to perform socket design with the help of a visualization of the limb's internal structure. The image resolution and measurement accuracy of the system were tested using a wire phantom and a contrast tissue mimicking phantom, respectively. Preliminary results from amputee patients are presented and the sources of measurement error are discussed.

Sirt6 protects cardiomyocytes against doxorubicin-induced cardiotoxicity by inhibiting P53/Fas-dependent cell death and augmenting endogenous antioxidant defense mechanisms

Sirt6, a class III NAD⁺-dependent deacetylase of the sirtuin family, is a highly specific H3 deacetylase and plays important roles in regulating cellular growth and death. The induction of oxidative stress and death is the critical mechanism involved in cardiomyocyte injury and cardiac dysfunction in doxorubicin-induced cardiotoxicity, but the regulatory role of Sirt6 in the fate of DOX-impaired cardiomyocytes is poorly understood. In the present study, we exposed Sirt6 heterozygous (Sirt6^+/-) mice and their littermates as well as cultured neonatal rat cardiomyocytes to DOX, then investigated the role of Sirt6 in mitigating oxidative stress and cardiac injury in the DOX-treated myocardium. Sirt6 partial knockout or silencing worsened cardiac damage, remodeling, and oxidative stress injury in mice or cultured cardiomyocytes with DOX challenge. Cardiomyocytes infected with adenoviral constructs encoding Sirt6 showed reversal of this DOX-induced damage. Intriguingly, Sirt6 reduced oxidative stress injury by upregulating endogenous antioxidant levels, interacted with oxidative stress-stirred p53, and acted as a co-repressor of p53 in nuclei. Sirt6 was recruited by p53 to the promoter regions of the target genes Fas and FasL and further suppressed p53 transcription activity by reducing histone acetylation. Sirt6 inhibited Fas/FasL signaling and attenuated both Fas-FADD-caspase-8 apoptotic and Fas-RIP3 necrotic pathways. These results indicate that Sirt6 protects the heart against DOX-induced cardiotoxicity by upregulating endogenous antioxidants, as well as suppressing oxidative stress and cell death signaling pathways dependent on ROS-stirred p53 transcriptional activation, thus reducing Fas-FasL-mediated apoptosis and necrosis. •Sirt6 is significantly decreased in DOX-insulted mouse hearts and cardiomyocytes. •Sirt6 attenuates DOX-induced cardiac atrophy, dysfunction and oxidative stress. • Sirt6 reduces oxidative stress injury by upregulating endogenous antioxidants. • Sirt6 interacts with p53 as a co-repressor to suppress p53 transcriptional regulation and inhibits Fas-FasL-mediated apoptosis and necrosis downstream of p53.

Cucurbitacin I induces cancer cell death through the endoplasmic reticulum stress pathway

Endoplasmic reticulum stress (ERS) is usually involved in tumor development and progression, and anticancer agents have recently been recognized to induce ERS. Cucurbitacin-I showed a potent anticancer action by inducing apoptosis through the inhibition of signal transducer and activator of transcription 3 pathway and triggering autophagic cell death. It is not known whether ERS mediates the cancer cell death induced by cucurbitacin-I. Here, we investigated the role of ERS in cucurbitacin-I-treated SKOV3 ovarian cancer cells and PANC-1 pancreatic cancer cells. We confirmed that cucurbitacin-I caused cell death and stirred excessive ERS levels by activating inositol requiring enzyme 1α (IRE1α) and protein kinase R-like endoplasmic reticulum kinase (PERK), as well as PERK downstream factors, including IRE1α and C/EBP homologous protein, but not activating transcription factor 6 (ATF6α) pathway, which was in parallel with the increased Bax and caspase-12-dependent ERS-associated apoptosis, autophagy and autophagy flux levels and caspase-independent nonapoptotic cell death. Furthermore, 4-phenylbutyrate, an ERS inhibitor, suppressed cucurbitacin-I-induced apoptosis, autophagy, autophagy flux, and autophagic cell death. Simultaneously, there are positive correlations among ERS and cucurbitacin-I-induced reactive oxygen species and Ca ²⁺ . Our results suggested that cucurbitacin-I-induced cancer cell death through the excessive ERS and CHOP-Bax and caspase-12-dependent ERS-associated apoptosis, as well as ERS-dependent autophagy, autophagy flux, and caspase-independent nonapoptotic cell death. These novel signaling insights may be useful for developing new, effective anticancer strategies in oncotherapy.

Management with willow short rotation coppice increase the functional gene diversity and functional activity of a heavy metal polluted soil

We studied the microbial functional diversity, biochemical activity, heavy metals (HM) availability and soil toxicity of Cd, Pb and Zn contaminated soils, kept under grassland or short rotation coppice (SRC) to attenuate the risks associated with HM contamination and restore the soil ecological functions. Soil microbial functional diversity was analyzed by the GeoChip, a functional gene microarray containing probes for genes involved in nutrient cycling, metal resistance and stress response. Soil under SRC showed a higher abundance of microbial genes involved in C, N, P and S cycles and resistance to various HM, higher microbial biomass, respiration and enzyme activity rates, and lower HM availability than the grassland soil. The linkages between functional genes of soil microbial communities and soil chemical properties, HM availability and biochemical activity were also investigated. Soil toxicity and N, P and Pb availability were important factors in shaping the microbial functional diversity, as determined by CCA. We concluded that in HM contaminated soils the microbial functional diversity was positively influenced by SRC management through the reduction of HM availability and soil toxicity increase of nutrient cycling. The presented results can be important in predicting the long term environmental sustainability of plant-based soil remediation.

Estival distribution of dissolved metal concentrations in Liaodong Bay

The temporal and spatial distributions of Cu, Pb, Zn, and Cd in surface water of the Liaodong Bay were studied based on samples collected at 16 sites in June and August from 2001 to 2005. The temporal distribution showed decreasing trends. The concentrations of dissolved metals in the Liaodong Bay were 4.34, 3.21, 31.54, and 0.995 mug/L for Cu, Pb, Zn, and Cd, respectively. Cu and Pb were scattered near the estuaries, and Zn and Cd were mainly found near the Wuli River. Rivers were the main metals pollution sources in the Bay.

Prim-O-glucosycimifugin attenuates liver injury in septic mice by inhibiting NLRP3 inflammasome/caspase-1 signaling cascades in macrophages

BACKGROUND

Liver dysfunction and liver failure are serious complications of sepsis, directly leading to septic progression and death. Now, there is no specific therapeutics available for sepsis-related liver dysfunction. Prim-O-glucosylcimifugin (POG), a chromone richest in the roots of Saposhnikovia divaricata (Turcz.) Schischk, is usually used to treat headache, rheumatoid arthritis and tetanus. While, the underlying mechanisms of POG against sepsis-induced liver damage and dysfunction are still not clear.

PURPOSE

To study the anti-sepsis effect of POG, and its pharmacological mechanism to protect liver injury by weakening the function of macrophages in septic livers through inhibiting NOD-like receptor protein 3 (NLRP3) inflammasome pathway.

METHOD

In vivo experiments, septic mouse model was induced by cecal ligation and puncture (CLP), and then the mortality was detected, liver inflammatory damages and plasma biomarkers of liver injury were evaluated by histopathological staining and biochemical assays, respectively. In vitro experiments, mouse primary peritoneal macrophages were treated with lipopolysaccharide (LPS) and ATP, and then the activated-inflammasomes, macrophage migration and polarization were detected by ASC immunofluorescence staining, transwell and flow cytometry assays, respectively. NLRP3 inflammasome components NLRP3, caspase-1, IL-1β and IL-18 protein expressions were detected using western blot assays, and the contents of IL-1β and IL-18 were measured by ELISA assays.

RESULTS

POG treatment significantly decreased the mortality, liver inflammatory damages, hepatocyte apoptosis and plasma biomarkers of liver injury in CLP-challenged male WT mice, which were comparable to those in ibuprofen (a putative anti-inflammatory drug)-supplemented septic male WT mice and septic NLRP3 deficient-male mice. POG supplementation significantly suppressed NLRP3 inflammasome activation in septic liver tissues and cultured macrophages, by significantly reducing NLRP3, cleaved-caspase-1, IL-1β and IL-18 levels, the activated-inflammasome ASC specks, and macrophage infiltration and migration, as well as M1-like polarization, but significantly increasing M2-like polarization. These findings were similar to the pharmacological effects of ibuprofen, NLRP3 deficiency, and a special NLRP3 inhibitor, MCC950.

CONCLUSION

POG protected against sepsis by inhibiting NLRP3 inflammasome-mediated macrophage activation in septic liver and attenuating liver inflammatory injury, indicating that it may be a potential anti-sepsis drug candidate.

MiR-21 enhanced glioma cells resistance to carmustine via decreasing Spry2 expression

OBJECTIVE

Gliomas are accompanied with high mortality owning to their invasive peculiarity and vulnerability to drug resistance. miR-21 is a vital oncogenic miRNA that regulates drug resistance of tumor cells. This study aims to elucidate the function of miR-21 in human glioma cells resistant to carmustine (BCNU) and to demonstrate the underlying molecular mechanism.

MATERIALS AND METHODS

BCNU-sensitive cells (SWOZ2 cells) were transfected with miR-21 agomir and negative control, and BCNU-resistance cells (SWOZ2-BCNU cells) were transfected with miR-21 antagomir and negative control. The Real-time fluorescence quantitative PCR was used to detect and compare the levels of miR-21expression between SWOZ2-BCNU and SWOZ2 cells. The drug sensitivity of these cells to BCNU was determined by Cell Counting Kit-8 (CCK-8) assay. The protein expression of Spry2 was detected by Western blotting.

RESULTS

The expression level of miR-21 was remarkably higher in SWOZ2-BCNU cells than that in SWOZ2 cells. The half-maximal inhibitory concentration (IC50) of BCNU was obviously higher for SWOZ2-BCNU cells than that for SWOZ2 cells. Besides, we found that aberrant expression of miR-21 in SWOZ2-BCNU cells is responsible for glioma BCNU-resistance. Consistently, Spry2 protein levels were significantly reduced in SWOZ2-BCNU as well as in miR-21 agomir-transfected cells, inversely correlated to miR-21 expression. The results of si-Spry2 co-transfection suggested that the effect of miR-21 on glioma BCNU-resistance is mediated through Spry2.

CONCLUSIONS

miR-21 enhances the resistance of human glioma cells to BCNU by decreasing the expression of Spry2 protein. Thus, Spry2 may be a novel therapeutic target for treating glioma BCNU-resistance.

Formation mechanism of shock-induced particle jetting

The shock dissemination of granular rings or shells is characterized by the formation of coherent particle jets that have different dimensions from those associated with the constituent grains. In order to identify the mechanisms governing the formation of particle jets, we carry out the simulations of the shock dispersal of quasi-two-dimensional particle rings based on the discrete-element method. The evolution of the particle velocities and contact forces on the time scales ranging from microseconds to milliseconds reveals a two-stage development of particle jets before they are expelled from the outer surface. Much effort is made to understand the particle agglomeration around the inner surface that initiates the jet formation. The shock interaction with the innermost particle layers generates a heterogeneous network of force chains with clusters of strong contacts regularly spaced around the inner surface. Momentum alongside the stresses is primarily transmitted along the strong force chains. Therefore, the clustering of strong force chains renders the agglomeration of fast-moving particles connected by strong force chains. The fast-moving particle clusters subsequently evolve into the incipient particle jets. The following competition among the incipient jets that undergo unbalanced growth leads to substantial elimination of the minor jets and the significant multiplication of the major jets, the number of jets thus varying with time. Moreover, the number of jets is found to increase with the strength of the shock loading due to an increased number of jets surviving the retarding effect of major jets.

Biosynthesis of poly-γ-glutamic acid in Escherichia coli by heterologous expression of pgsBCAE operon from Bacillus

AIMS

Poly-γ-glutamic acid (γ-PGA) is an excellent water-soluble biosynthesis material. To confirm the rate-limiting steps of γ-PGA biosynthesis pathway, we introduced a heterologous Bacillus strain pathway and employed an enzyme-modulated dismemberment strategy in Escherichia coli.

METHODS AND RESULTS

In this study, we heterologously introduced the γ-PGA biosynthesis pathway of two laboratory-preserved strains-Bacillus amyloliquefaciens FZB42 and Bacillus subtilis 168 into E. coli, and compared their γ-PGA production levels. Next, by changing the plasmid copy numbers and supplying sodium glutamate, we explored the effects of gene expression levels and concentrations of the substrate l-glutamic acid on γ-PGA production. We finally employed a two-plasmid induction system using an enzyme-modulated dismemberment of pgsBCAE operon to confirm the rate-limiting genes of the γ-PGA biosynthesis pathway.

CONCLUSION

Through heterologously over-expressing the genes of the γ-PGA biosynthesis pathway and exploring gene expression levels, we produced 0·77 g l^-1 γ-PGA in strain RSF-EBCAE(BS). We also confirmed that the rate-limiting genes of the γ-PGA biosynthesis pathway were pgsB and pgsC.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work is beneficial to increase γ-PGA production and study the mechanism of γ-PGA biosynthesis enzymes.

5-Lipoxagenase deficiency attenuates L-NAME-induced hypertension and vascular remodeling

BACKGROUND

Abnormalities of the L-arginine-nitric oxide pathway induce hypertension. 5-Lipoxygenase (5-LO) is the key enzyme involved in synthesis of leukotrienes (LTs). However, whether nitricoxide synthase dysfunction induces hypertensive vascular remodeling by regulating 5-LO activity and its downstream inflammatory metabolites remains unknown.

METHODS AND RESULTS

Six-week L-NAME treatment significantly induced hypertension and vascular remodeling in both wild-type (WT) and 5-LO-knockout (5-LO-KO) mice, and blood pressure in caudal and carotid arteries was lower in 5-LO-KO than WT mice with L-NAME exposure. On histology, L-NAME induced less media thickness, media-to-lumen ratio, and collagen deposition and fewer Ki-67-positive vascular smooth muscle cells (VSMCs) but more elastin expression in thoracic and mesenteric aortas of 5-LO-KO than L-NAME-treated WT mice. L-NAME significantly increased LT content, including LTB4 and cysteinyl LT (CysLTs), in plasma and neutrophil culture supernatants from WT mice. On immunohistochemistry, L-NAME promoted the colocalization of 5-LO and 5-LO-activating protein on the nuclear envelope of cultured neutrophils, which was accompanied by elevated LT content in culture supernatants. In addition, LTs significantly promoted BrdU incorporation, migration and phenotypic modulation in VSMCs.

CONCLUSION

L-NAME may activate the 5-LO/LT pathway in immune cells, such as neutrophils, and promote the products of 5-LO metabolites, including LTB4 and CysLTs, which aggravate vascular remodeling in hypertension. 5-LO deficiency may protect against hypertension and vascular remodeling by reducing levels of 5-LO downstream inflammatory metabolites.

Mogrol suppresses lung cancer cell growth by activating AMPK-dependent autophagic death and inducing p53-dependent cell cycle arrest and apoptosis

Lung carcinoma is the leading cause of cancer-related death worldwide. Chemotherapy remains the cornerstone of lung cancer treatment. Unfortunately, most types of cancer will develop resistance to chemotherapies over the time. One of the efforts to prevent the chemotherapy resistance is to find alternative chemotherapy drugs. Mogrol has been found to have antitumor activity. However, little is known about the pharmacological mechanisms underlying the suppression of mogrol on lung cancers. In this study, we observed that mogrol exposure significantly reduced the tumor volume and weight in tumor-bearing nude mice without obvious effect on body weight and cardiac function. Mogrol also significantly inhibited the proliferation and migration of lung cancer cells, including non-small-cell lung carcinoma cells, A549, H1299, H1975 and SK-MES-1 cells, with no obvious effect on control human bronchial epithelial cells (HBE). Further studies revealed that mogrol stirred excessive autophagy and autophagic flux, and finally, autophagic cell death, in lung cancer cells, which could be attenuated by autophagy inhibitors, 3-MA and chloroquine. Furthermore, mogrol significantly activated AMPK to induce autophagy and autophagic cell death, which could be abrogated by Compound C, an AMPK inhibitor. In addition, mogrol induced a significant increase in p53 activity in lung cancer cells, accompanied with cell cycle arrest and apoptosis, which could be weakened by p53 silence. Our results indicated that mogrol effectively suppressed lung cancer cells in vivo and in vitro by inducing the excessive autophagy and autophagic cell death via activating AMPK signaling pathway, as well as cell cycle arrest and apoptosis via activating p53 pathway.

Influence of surgical team activity on airborne bacterial distribution in the operating room with a mixing ventilation system: a case study at St. Olavs Hospital

BACKGROUND

Operating rooms (ORs) have strict requirements regarding cleanliness. While existing standards concerning the ventilation and staff guidelines are theoretically sufficient to subvert the threats posed by micro-organisms within the room, there exist potential sources of contamination due to human activity around the area. Studies exploring this influence of human activity on distribution of micro-organism contamination in ORs have relied on manual observations, or indirect methods such as number of door openings.

AIM

To utilize depth registration sensing technology to identify the activities of surgical staff and investigate their effect on the distribution of airborne micro-organism contamination in ORs.

METHODS

A mock surgical experiment was performed using a depth registration technique for the dynamic capturing of human presence and activity levels. Field measurements were carried out in one real OR to analyse its influence on the bacterial distribution in ORs with mixing ventilation system.

FINDINGS

Bacterial contamination levels tended to correlate with higher activity levels, albeit with some inconsistencies. The highest activity levels were around the surgical bed when the patient was placed, and around the instrument table during the surgical procedure. Locations with obstructions had the highest cfu densities, indicating that airflow patterns are important in such spaces.

CONCLUSION

Our activity monitoring methods demonstrate a novel means of studying the influences of human activities in hospital rooms.

Possible experimental measure theory for the XXX-Heisenberg chain

Raising and lowering operators for the XXX-Heisenberg chain are derived explicitly; as a result the dipole moment operator is established. Based on the dipole transition mechanism in an external time-dependent magnetic field, we propose a possible experimental measure theory to detect the energy spectrum of the spin chain.

Evaluation of pulmonary ventilation in COVID-19 patients using oxygen-enhanced three-dimensional ultrashort echo time MRI: a preliminary study

AIM

To evaluate the lung function of coronavirus disease 2019 (COVID-19) patients using oxygen-enhanced (OE) ultrashort echo time (UTE) MRI.

MATERIALS AND METHODS

Forty-nine patients with COVID-19 were included in the study. The OE-MRI was based on a respiratory-gated three-dimensional (3D) radial UTE sequence. For each patient, the percent signal enhancement (PSE) map was calculated using the expression PSE = (S_100% – S_21%)/S_21%, where S_21% and S_100% are signals acquired during room air and 100% oxygen inhalation, respectively. Agreement of lesion detectability between UTE-MRI and computed tomography (CT) was performed using the kappa test. The Mann–Whitney U-test was used to evaluate the difference in the mean PSE between mild-type COVID-19 and common-type COVID-19. Spearman's test was used to assess the relationship between lesion mean PSE and lesion size. Furthermore, the Mann–Whitney U-test was used to evaluate the difference in region of interest (ROI) mean PSE between normal pulmonary parenchyma and lesions. The Kruskal–Wallis test was applied to test the difference in the mean PSE between different lesion types.

RESULTS

CT and UTE-MRI reached good agreement in lesion detectability. Ventilation measures in mild-type patients (5.3 ± 5.5%) were significantly different from those in common-type patients (3 ± 3.9%). Besides, there was no significant correlation between lesion mean PSE and lesion size. The mean PSE of COVID-19 lesions (3.2 ± 4.9%) was significantly lower than that of the pulmonary parenchyma (5.4 ± 3.9%). No significant difference was found among different lesion types.

CONCLUSION

OE-UTE-MRI could serve as a promising method for the assessment of lung function or treatment management of COVID-19 patients.

Rapid atraumatic sex identification of developmental day 14-16 mice

Embryonic mice have been used widely to study organ development. Days 14-16 are critical for sex organ development and differentiation in mice. Current methods for sex identification are limited. Even the simplest polymerase chain reaction method may injure the embryo. We determined that morphologic analysis of embryonic mammary anlagen could be used for rapid atraumatic sex identification of day 14-16 mice. The accuracy of our method was verified by molecular and anatomical approaches.

Variable-temperature scanning tunneling microscopy and scanning tunneling spectroscopy study on copper phthalocyanine ultrathin films on a Au(111) surface

Variable-temperature high-resolution scanning tunneling microscopy (STM) images reveal that well-ordered copper phthalocyanine (CuPc) strips can be self-assembled by depositing CuPc molecules on a Au(111) surface. The self-assembled strips are supposed to result from the balance of the intermolecular interaction and the interaction between the molecules and substrate during annealing. The energy band (approximately 1.9-2.1 eV) of CuPc, measured by scanning tunneling spectroscopy (STS), is comparable to the optical band gap (approximately 1.7 eV). Spectroscopic measurements confirm that a dipole layer and/or an effect of image force exist at the CuPc/Au(111) interface.

Lithography and doping in strained Si towards atomically precise device fabrication

We investigate the ability to introduce strain into atomic-scale silicon device fabrication by performing hydrogen lithography and creating electrically active phosphorus δ-doped silicon on strained silicon-on-insulator (sSOI) substrates. Lithographic patterns were obtained by selectively desorbing hydrogen atoms from a H resist layer adsorbed on a clean, atomically flat sSOI(001) surface with a scanning tunnelling microscope tip operating in ultra-high vacuum. The influence of the tip-to-sample bias on the lithographic process was investigated allowing us to pattern feature-sizes from several microns down to 1.3 nm. In parallel we have investigated the impact of strain on the electrical properties of P:Si δ-doped layers. Despite the presence of strain inducing surface variations in the silicon substrate we still achieve high carrier densities (>1.0 × 10(14) cm(-2)) with mobilities of ∼100 cm(2) V(-1) s(-1). These results open up the possibility of a scanning-probe lithography approach to the fabrication of strained atomic-scale devices in silicon.

CD8αα+T cells exert a pro-inflammatory role in patients with psoriasis

Background

Psoriasis is a common chronic inflammatory disease caused by excessive activation of CD4⁺T cells, including Th17, Th1 and Th22. The role of CD8⁺T cells in psoriasis pathogenesis remains poorly understood.

Aim

To identify the phenotype of CD8⁺T cells in patients with psoriasis and to investigate its role in the formation of lesions.

Methods

The phenotype of CD8⁺T cells in psoriatic lesions was detected by immunofluorescence staining. Flow cytometry was performed to detect their phenotype in peripheral blood. Thereafter, coculture of CD8αα⁺T cells with autogenous CD4⁺T cells was performed to investigate the function of CD8αα⁺T cells in patients with psoriasis. Finally, pro‐inflammatory factors produced by CD8αα⁺T cells were examined by immunofluorescence staining and flow cytometry.

Results

Compared to the CD8αβ⁺T cells, CD8αα⁺T cell infiltration in psoriatic lesions markedly increased. Moreover, epidermal CD8αα⁺T cells exhibited tissue‐resident memory T cells (T_RM) phenotypes and dermal CD8αα⁺T cells exhibited effector memory (T_EM) phenotypes in psoriatic lesions. Additionally, we found that CD8αα⁺T cells from patients with psoriasis did not express the markers of regulatory T cells and could promote the proliferation of CD4⁺T effector cells and produce interleukin‐17 and interferon‐γ.

Conclusions

Our findings demonstrate that CD8αα⁺T cells contribute to the pathogenesis of psoriasis by producing pro‐inflammatory factors.