A reaction rate measurement experimental program of China experimental fast reactor.

The study of the nuclear reaction rate distribution in the MOX core of China Experimental Fast Reactor is a necessary condition for obtaining the operating license. From the characteristics of core structure, both the principle of experimental and experimental system are studies, emphasized on the scheme design such as the size of foils, the irradiation power and counting rate. Firstly, based on the Monte Carlo Code（MCNP）and NJOY codes, the distribution of reaction rates is obtained. MCNP is a general-purpose Monte Carlo N-Particle code that can be used for neutron, photon, electron, and so on. The NJOY nuclear data processing system is a comprehensive computer code package for producing to cross sections and related nuclear parameters from ENDF/B VIII.0 evaluated nuclear data. Secondly, the activity measurement of foils was obtained by HPGE, then the reaction rate is determined by data processing. It is worth mentioning that the experimental reactivity introduction has a negligible effect on the reactor core by MCNP. Finally, a set of activation experiment scheme that is suitable for CEFR MOX core is formed, which serves as a guide to carry out activation method experiments.

Combined effect of hydrotherapy and transcranial direct-current stimulation on children with cerebral palsy: A protocol for a randomized controlled trial.

BACKGROUND: Cerebral palsy (CP) is a neurodevelopmental disorder caused by a brain injury resulting in poor coordination and motor control deficits, which is one of the most common physical disabilities in children. CP brings a heavy burden on families and society and becomes a significant public health issue. In recent years, hydrotherapy, and transcranial direct current stimulation (tDCS) as a physical therapy for CP is developing rapidly. When hydrotherapy and tDCS are used to treat separately, it has positive therapeutic effect in children with CP. The development of new therapies in combination with physical rehabilitation approaches is critical to optimize functional outcomes. tDCS has attracted interest in this context, because of significant functional improvements have been demonstrated in individuals with brain injuries after a short period of cerebral stimulation. Since the onset of this work, tDCS has been used in combination with constraint-induced therapy, virtual reality therapy to potentiate the treatment effect. Up to now, there are no studies on the effect of a combined application of hydrotherapy and tDCS in children with CP. We will conduct a 2-arm parallel clinical trial to investigate the effect of a combined application of tDCS and hydrotherapy. METHODS AND ANALYSIS: This study is an outcome assessor and data analyst-blinded, randomized, controlled superiority trial during the period from October 2021 to December 2023. CP patients meeting the inclusion criteria will be allocated in a 1:1 ratio into the treatment group (hydrotherapy plus tDCS), or the control group (treatment as usual). All participants will receive 30 sessions of treatment over 10 weeks. The primary outcomes will be the difference in the Gross Motor Function Assessment and Pediatric Balance Scale during rest and activity. The secondary outcomes will be the difference in adverse effects between the control and treatment groups. CONCLUSIONS: This study aims to estimate the efficacy of a combined application of tDCS and hydrotherapy in patients with CP. TRIAL REGISTRATION: This study protocol was registered in Chinese ClinicalTrials.gov, ID: ChiCTR2100047946.

CT-guided transthoracic needle biopsy of pulmonary lesions: comparison between the cutting needle and aspiration needle.

OBJECTIVES: To compare CT-guided transthoracic cutting needle biopsy (TCNB) with transthoracic aspiration needle biopsy (TANB) for pulmonary lesions with respect to the diagnostic accuracy and complication rate. METHODS: Of the 859 cases that underwent consecutive CT-guided biopsy of pulmonary lesions, 713 cases confirmed by surgical pathology or clinical follow-up were enrolled. Of these, the first consecutive 275 cases underwent TANB, and the remaining 438 received TCNB. The final diagnosis determined the accuracy of biopsy. Based on the post-biopsy CT and clinical medical records, the presence or absence of biopsy-related complications was determined. The χ2 test was used to compare the differences between TCNB and TANB in terms of diagnostic accuracy and complication rate. RESULTS: Among the 713 biopsy lesions, the final diagnosis was malignant in 411 cases and benign in 302 cases. As compared to TANB, the diagnostic accuracy of TCNB (98.9% vs 93.8%, χ2 = 14.35, p < 0.01), sensitivity to malignant lesions (97.8% vs 90.6%, χ2 = 10.58, p < 0.01), negative predictive value (97.6% vs 84.8%, χ2 = 19.03, p < 0.01), and specific diagnostic rate for benign lesions (73.4% vs 57.9%, χ2 = 7.29, p < 0.01) were improved. On the other hand, a statistical difference was detected between TCNB and TANB with respect to the incidence of pneumothorax (20.6% vs 13.1%, χ2 = 6.46, p = 0.01), hemorrhage (32.2% vs 13.1%, χ2 = 33.03, p < 0.01), and hemoptysis (8.2% vs 3.3%, χ2 = 6.87, p < 0.01). One patient died just several minutes after TCNB due to severe hemorrhage with hemoptysis. CONCLUSIONS: Compared to TANB, CT-guided TCNB improves the diagnostic accuracy of pulmonary lesions, but complication rate increases significantly. ADVANCES IN KNOWLEDGE: In general, TCNB should be recommended, especially for highly suspicious benign lesions. For patients with small lesions adjacent to vessels or vessels within the lesion, TANB should be considered.

Avoiding health worker infection and containing the coronavirus disease 2019 pandemic: Perspectives from the frontline in Wuhan.

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused great public concern worldwide due to its high rates of infectivity and pathogenicity. The Chinese government responded in a timely manner, alleviated the dilemma, achieved a huge victory and lockdown has now been lifted in Wuhan. However, the outbreak has occurred in more than 200 other countries. Globally, as of 9:56 am CEST on 19 May 2020, there have been 4,696,849 confirmed cases of COVID-19, including 315,131 deaths, reported to Word Health Organization (WHO). The spread of COVID-19 overwhelmed the healthcare systems of many countries and even crashed the fragile healthcare systems of some. Although the situation in each country is different, health workers play a critical role in the fight against COVID-19. In this review, we highlight the status of health worker infections in China and other countries, especially the causes of infection in China and the standardised protocol to protect health workers from the perspective of an anaesthesiologist, in the hope of providing references to reduce medical infections and contain the COVID-19 epidemic.

A novel transverse ultrasonography technique for minimally displaced lateral humeral condyle fractures in children.

INTRODUCTION: Management of minimally displaced lateral humeral condyle fractures in pediatric patients is controversial. This is primarily because with current imaging modalities it is difficult to accurately and conveniently determine the stability of the fractures by detecting the integrity of the cartilage hinge. Nevertheless, transverse ultrasonography has not been intensively reported in previous studies. HYPOTHESIS: Transverse ultrasonography can determine the integrity of the cartilage hinge in minimally displaced lateral condyle fractures. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 39 pediatric patients with minimally displaced fractures of the lateral humeral condyle who underwent transverse ultrasonography between 2014 and 2017. Conservative treatment was given to pediatric patients with intact cartilage hinges that had been confirmed by transverse ultrasound images. Surgical treatment was recommended for pediatric patients with disrupted cartilage hinges. Data regarding healing of the lateral humeral condyle fractures were recorded and analyzed. RESULTS: According to transverse ultrasonography, there were 14 children with intact cartilage hinges and 25 children with disrupted cartilage hinges. Fourteen children with intact cartilage hinges of the fracture were treated conservatively, and none of them showed secondary displacement. There were 16 children in whom there was surgical intervention, and 9 other children decided to have conservative treatment among the 25 children with disruption of the cartilage hinge. Five of these 9 children who underwent conservative treatment were found to have further displacement during an average of 12.6 days after the fracture event, and no other patient was found to have further displacement. CONCLUSION: Transverse ultrasonography can simply and accurately determine the stability of minimally displaced lateral condyle fractures without sedation, ionizing radiation or invasive techniques. We recommend routine use of transverse ultrasonography to detect stability of the fractures, which can effectively avoid inadequate treatment and unnecessary surgery in pediatric patients with minimally displaced fractures of the lateral humeral condyle. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Optimization design research for 89Sr production in China Experimental Fast Reactor.

As the first sodium cooled fast reactor in China, China Experimental Fast Reactor (CEFR) has many characteristics, such as high power rating, high neutron flux and high neutron leakage as its hard spectrum. These leakage neutrons can be used to produce 89Sr by fast neutrons (n, p) reaction. By means of some special designs, including designing optimized target assembly, choosing reasonable irradiation location and appropriate irradiation cycle length, in order to improve specific activity of 89Sr. The MNCP code was used to the calculations coupled ORIGRN2 procedure. The higher activity of 89Sr can be obtained by these optimization designs, so it is feasible to produce 89Sr in the fuel region of CEFR.

An efficacy analysis of whole-body magnetic resonance imaging in the diagnosis and follow-up of polymyositis and dermatomyositis.

OBJECTIVES: To evaluate the value of whole-body magnetic resonance imaging (WBMRI) in diagnosing muscular and extra muscular lesions in patients with polymyositis (PM) and dermatomyositis (DM). METHODS: A retrospective analysis of WBMRI data from PM/DM patients who met the Bohan and Peter diagnostic criteria was performed. X2 test was used to compare the rate of positive diagnosis of newly diagnosed patients using WBMRI, serum creatine kinase test, and EMG. McNemar test was used to compare the performance of WBMRI and chest CT in detecting interstitial lung disease (ILD). RESULTS: The study included 129 patients (30 PM cases and 99 DM cases). Of them, 81.4% (105/129) showed a visible inflammatory muscular edema on their WBMRI; 29.5% (38/129) had varying degrees of fatty infiltration (9 cases with clear muscular atrophy). Of the 66 newly diagnosed patients, the positive rates of WBMRI, muscle biopsy, serum creatine kinase test and EMG were 86.4% (57/66), 92.4% (61/66), 71.2% (47/66) and 71.1% (32/45), respectively. There was no significant difference in the positive rates between WBMRI and muscle biopsy (X2 = 1.28, P = 0.258). The WBMRI had a higher positive rate than both serum creatine kinase test (X2 = 4.53, P = 0.033) and EMG (X2 = 3.92, P = 0.047). In addition to muscular changes, WBMRI also detected interstitial lung disease (ILD) in 38 cases (29.5%), osteonecrosis in 15 cases (11.6%), and neoplastic lesions (5 malignant; 7 benign) in 12 cases (9.3%). Of the 61 patients who underwent routine chest CT examinations, the WBMRI and CT revealed ILD in 29 cases and 35 cases respectively. There was no significant difference in the sensitivity between WBMRI and CT (p = 0.146). CONCLUSIONS: WBMRI is a sensitive, non-invasive and efficient imaging method. It comprehensively displays the extent of muscular involvement in PM/DM patients, and it has the ability to diagnose other associated extra muscular diseases, such as ILD and systemic malignancy. WBMRI can also help screen steroid-induced osteonecrosis.

The application of T2W SPIR-FLAIR in the diagnosis of hip synovitis in patients with spondyloarthritis.

OBJECTIVE: To investigate the feasibility and accuracy of T2 weighted spectral pre-saturation inversion recovery combined with fluid-attenuated inversion recovery (T2W SPIR-FLAIR) in the diagnosis of hip synovitis in patients with spondyloarthritis (SpA). METHODS: 10 volunteers underwent a T2W SPIR and 4 T2W SPIR-FLAIR sequence scans with different inversion times (TIs) to determine the optimum TI that could effectively suppress the intra-articular fluid signals. Hip MRI including T2W SPIR-FLAIR and enhanced T1 weighted (T1W) SPIR sequences was performed in 45 patients with SpA and totally 90 hips were evaluated. McNemar's test and Kappa test were used to compare the diagnostic results of synovitis between T2W SPIR-FLAIR and enhanced T1W SPIR. RESULTS: A TI of 2100 ms was selected as the optimum TI. 32 hips from 17 patients exhibited high signal intensity within the articular cavity on both T2W SPIR-FLAIR and enhanced T1W SPIR sequences, while only 3 hips showed high signals within the articular cavity on T2W SPIR-FLAIR. The remaining 55 hips did not show high signals within the articular cavity on both sequences. The T2W SPIR-FLAIR and enhanced T1W SPIR sequences had similar values in the diagnosis of hip synovitis (p = 0.25) and a high degree of diagnostic consistency (Kappa = 0.929). CONCLUSION: T2W SPIR-FLAIR can effectively suppress the intra-articular fluid signals, while retaining the signals of thickened synovial membranes and can be used for the diagnosis of hip synovitis in patients with SpA. Advances in knowledge: The enhanced T1W SPIR is a classic sequence for synovitis diagnosis, but it requires the injection of contrast agents. The T2W SPIR-FLAIR and enhanced T1W SPIR sequences had similar values in the diagnosis of hip synovitis (p = 0.25) and a high degree of diagnostic consistency (Kappa = 0.929).

The novel late Na+ current inhibitor, GS-6615 (eleclazine) and its anti-arrhythmic effects in rabbit isolated heart preparations.

BACKGROUND AND PURPOSE: Enhanced late Na+ current (late INa ) in the myocardium is pro-arrhythmic. Inhibition of this current is a promising strategy to stabilize ventricular repolarization and suppress arrhythmias. Here, we describe GS-6615, a selective inhibitor of late INa , already in clinical development for the treatment of long QT syndrome 3 (LQT3). EXPERIMENTAL APPROACH: The effects of GS-6615 to inhibit late INa , versus other ion currents to shorten the ventricular action potential duration (APD), monophasic APD (MAPD) and QT interval, and decrease to the incidence of ventricular arrhythmias was determined in rabbit cardiac preparations. To mimic the electrical phenotype of LQT3, late INa was increased using the sea anemone toxin (ATX-II). KEY RESULTS: GS-6615 inhibited ATX-II enhanced late INa in ventricular myocytes (IC50  = 0.7 µM), shortened the ATX-II induced prolongation of APD, MAPD, QT interval, and decreased spatiotemporal dispersion of repolarization and ventricular arrhythmias. Inhibition by GS-6615 of ATX-II enhanced late INa was strongly correlated with shortening of myocyte APD and isolated heart MAPD (R2  = 0.94 and 0.98 respectively). In contrast to flecainide, GS-6615 had the minimal effects on peak INa . GS-6615 did not decrease the maximal upstroke velocity of the action potential (Vmax) nor widen QRS intervals. CONCLUSIONS AND IMPLICATIONS: GS-6615 was a selective inhibitor of late INa , stabilizes the ventricular repolarization and suppresses arrhythmias in a model of LQT3. The concentrations at which the electrophysiological effects of GS-6615 were observed are comparable to plasma levels associated with QTc shortening in patients with LQT3, indicating that these effects are clinically relevant.

CXC195 induces apoptosis and endoplastic reticulum stress in human hepatocellular carcinoma cells by inhibiting the PI3K/Akt/mTOR signaling pathway.

CXC195 exhibits strong protective effects against neuronal apoptosis by exerting antioxidant activity. However, the pharmacological function of CXC195 in cancer remains to be elucidated. The present study demonstrated that CXC195 exhibited significant cytotoxic effects, and induced cell cycle arrest and apoptosis in HepG2 human hepatocellular carcinoma (HCC) cell lines. Following treatment of HepG2 cells with 150 µΜ CXC195 for 24 , cell viability and the apoptotic rate were assessed using an MTT assay and Annexin V/propidium iodide staining followed by flow cytometric analysis. Molecular markers of the cell cycle, apoptosis, mitochondrial function and endoplasmic reticulum (ER) stress were analyzed by western blot or polymerase chain reaction analysis. Caspase activation, cytochrome c and apoptosis­inducing factor release, and analysis of the B cell lymphoma 2 (Bcl­2)­associated X protein/Bcl­2 ratio demonstrated that the anticancer effects of CXC195 in HepG2 cells were mediated by caspase and mitochondria­dependent apoptosis. CXC195 also induced the expression of ER stress­associated proteins, including CCAAT­enhancer­binding protein homologous protein, and glucose­regulated proteins 94 and 78, and led to the activation of multiple branches of ER stress transducers, including inositol­requiring enzyme 1α­apoptosis signal­regulating kinase­p38/c­Jun N­terminal kinase, and protein kinase R­like endoplasmic reticulum kinase­eukaryotic translation initiation factor 2α­activating transcription factor (ATF)4 and ATF6, in the HepG2 cells. In addition, CXC195 inhibited the phosphorylation of phosphoinositide 3­kinase (PI3K), Akt and mammalian target of rapamycin (mTOR) in the HepG2 cells. These effects were enhanced following treatment with selected inhibitors of PI3K (LY294002), Akt (SH­6) and mTOR (rapamycin). Furthermore, these inhibitors enhanced the pro­apoptotic effects of CXC195 in the HepG2 cells. In conclusion, the results of the present study indicated that CXC195 induced apoptosis and ER stress in HepG2 cells through the inhibition of the PI3K/Akt/mTOR signaling pathway.

Icariin, a natural flavonol glycoside, extends healthspan in mice.

A major goal of aging research now is to find pharmacological manipulations in healthspan extension. Icariin is a flavonol isolated from medicinal herbal tonics. We have previously reported that icariin extended the healthspan of invertebrate models. Here, we showed that long-term treatment with icariin starting at 12months of age extended healthspan and mean lifespan in C57BL/6 mice. In all our assays associated with healthspan, such as behavioral tests and bone density analysis, we found that icariin boosted healthy features in mice. We also presented data indicating that such beneficial effects of icariin were due to at least two mechanisms: reduced oxidative stress indicated by the induction of antioxidant protein superoxide dismutase (SOD) activity and the decrease of oxidative marker malondialdehyde (MDA); maintained the genomic stability indicated by a reduction in DNA double-stranded breaks and down-regulation of DNA damage response genes. Our results indicated that icariin, a safe and widely used natural flavonol, extended healthspan and maintained genomic stability in a mammalian system.

Gastric myeloid sarcoma without acute myeloblastic leukemia.

Myeloid sarcomas (MS) involve extramedullary blast proliferation from one or more myeloid lineages that replace the original tissue architecture, and these neoplasias are called granulocytic sarcomas, chloromas or extramedullary myeloid tumors. Such tumors develop in lymphoid organs, bones (e.g., skulls and orbits), skin, soft tissue, various mucosae, organs, and the central nervous system. Gastrointestinal (GI) involvement is rare, while the occurrence of myeloid sarcomas in patients without leukemia is even rare. Here, we report a case of a 38-year-old man who presented with epigastric pain and progressive jaundice. An upper GI endoscopy had shown extensive multifocal hyperemic fold thickening and the spread of nodular lesions in the body of the stomach. Biopsies from the gastric lesions indicated myeloid sarcoma of the stomach. However, concurrent peripheral blood and bone marrow examinations showed no evidence of acute myeloid leukemia. For diagnosis, the immunohistochemical markers must be checked when evaluating a suspected myeloid sarcoma case. Accurate MS diagnosis determines the appropriate therapy and prognosis.

Ultrasound assessment of the elbow joint in infants and toddlers and its clinical significance.

BACKGROUND: Ultrasound can be used for the diagnosis of elbow injuries in infants and toddlers. However, ultrasound is highly operator-dependent and accurate ultrasound examinations require a complete understanding of the complex anatomy of the elbow joint. PURPOSE: To report the normal ultrasound anatomy of the elbow, particularly of the humeroulnar joint, in infants and toddlers. MATERIAL AND METHOD: Thirty subjects aged <3 years with no history of elbow injuries underwent ultrasound examinations of the elbow joint from six directions: (i) lateral to the humeroradial joint; (ii) anterior to the humeroradial joint; (iii) posterior to the humeroradial joint; (iv) medial to the humeroulnar joint; (v) anterior to the humeroulnar joint; and (vi) posterior to the humeroulnar joint. RESULTS: The appearance of the humeroradial joint observed from three directions was similar and resembled a pair of double fists ("double-breast sign"). The appearance of the humeroulnar joint observed from three directions was different, which is related to the irregular morphology of the medial sides of the humerus and ulna. Anteroposteriorly, the coronoid and olecranon epiphyses and coronoid fossa appear anteriorly and the olecranon and trochlear epiphyses and olecranon fossa appear posteriorly, resembling a "check-mark sign". The medial epicondyle, cubital tunnel and distal humerus appear together ("double-hump sign"). The "anterior hump" is the medial epicondyle and is always higher than the "posterior hump", which is the bony protrusion on the articular surface of the distal humerus. The ultrasound signal of cortical bone in the metaphysis of the distal humerus is continuous with that of the epiphysis of the medial epicondyle. CONCLUSION: Ultrasound is useful for the diagnosis of elbow injuries in infants and toddlers.

Diagnostic role of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for early and atypical bone metastases.

The bone metastasis appeared early before the bone imaging for most of the above patients. (99)Tc(m)-MDP ((99)Tc(m) marked methylene diphosphonate) bone imaging could diagnosis the bone metastasis with highly sensitivity, but with lower specificity. The aim of this study is to explore the diagnostic value of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for the early period atypical bone metastases. 15 to 30 mCi (99)Tc(m)-MDP was intravenously injected to the 34 malignant patients diagnosed as doubtful early bone metastases. SPECT, CT and SPECT/CT images were captured and analyzed consequently. For the patients diagnosed as early period atypical bone metastases by SPECT/CT, combining the SPECT/CT and MRI together as the SPECT/MRI integrated image. The obtained SPECT/MRI image was analyzed and compared with the pathogenic results of patients. The results indicated that 34 early period doubtful metastatic focus, including 34 SPECT positive focus, 17 focus without special changes by using CT method, 11 bone metastases focus by using SPECT/CT method, 23 doubtful bone metastases focus, 8 doubtful bone metastases focus, 14 doubtful bone metastases focus and 2 focus without clear image. Totally, SPECT/CT combined with SPECT/MRI method diagnosed 30 bone metastatic focus and 4 doubtfully metastatic focus. In conclusion, (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging shows a higher diagnostic value for the early period bone metastases, which also enhances the diagnostic accuracy rate.

Angioimmunoblastic T-cell lymphoma-associated pure red cell aplasia with abdominal pain.

Angioimmunoblastic T-cell lymphoma (AITL) is a unique type of peripheral T-cell lymphoma with a constellation of clinical symptoms and signs, including weight loss, fever, chills, anemia, skin rash, hepatosplenomegaly, lymphadenopathy, thrombocytopenia and polyclonal hypergammaglobulinemia. The histological features of AITL are also distinctive. Pure red cell aplasia is a bone marrow failure characterized by progressive normocytic anemia and reticulocytopenia without leucopenia or thrombocytopenia. However, AITL with abdominal pain and pure red cell aplasia has rarely been reported. Here, we report a rare case of AITL-associated pure red cell aplasia with abdominal pain. The diagnosis was verified by a biopsy of the enlarged abdominal lymph nodes with immunohistochemical staining.

Paroxysmal drastic abdominal pain with tardive cutaneous lesions presenting in Henoch-Schönlein purpura.

Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis mediated by IgA-immune complex deposition. It is characterized by the clinical tetrad of non-thrombocytopenic palpable purpura, abdominal pain, arthritis and renal involvement. The diagnosis of HSP is difficult, especially when abdominal symptoms precede cutaneous lesions. We report a rare case of paroxysmal drastic abdominal pain with gastrointestinal bleeding presented in HSP. The diagnosis was verified by renal damage and the occurrence of purpura.

Ca²âº channel activators reveal differential L-type Ca²âº channel pharmacology between native and stem cell-derived cardiomyocytes.

Human stem cell-derived cardiomyocytes provide new models for studying the ion channel pharmacology of human cardiac cells for both drug discovery and safety pharmacology purposes. However, detailed pharmacological characterization of ion channels in stem cell-derived cardiomyocytes is lacking. Therefore, we used patch-clamp electrophysiology to perform a pharmacological survey of the L-type Ca²âº channel in induced pluripotent and embryonic stem cell-derived cardiomyocytes and compared the results with native guinea pig ventricular cells. Six structurally distinct antagonists [nifedipine, verapamil, diltiazem, lidoflazine, bepridil, and 2-[(cis-2-phenylcyclopentyl)imino]-azacyclotridecane hydrochloride (MDL 12330)] and two structurally distinct activators [methyl 2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-1,4-dihydropyridine-3-carboxylate (Bay K8644) and 2,5-dimethyl-4-[2-(phenylmethyl)benzoyl]-1H-pyrrole-3-carboxylic acid methyl ester (FPL 64176)] were used. The IC50 values for the six antagonists showed little variability between the three cell types. However, whereas Bay K8644 produced robust increases in Ca²âº channel current in guinea pig myocytes, it failed to enhance current in the two stem cell lines. Furthermore, Ca²âº channel current kinetics after addition of Bay K8644 differed in the stem cell-derived cardiomyocytes compared with native cells. FPL 64176 produced consistently large increases in Ca²âº channel current in guinea pig myocytes but had a variable effect on current amplitude in the stem cell-derived myocytes. The effects of FPL 64176 on current kinetics were similar in all three cell types. We conclude that, in the stem cell-derived myocytes tested, L-type Ca²âº channel antagonist pharmacology is preserved, but the pharmacology of activators is altered. The results highlight the need for extensive pharmacological characterization of ion channels in stem cell-derived cardiomyocytes because these complex proteins contain multiple sites of drug action.

Secretagogues of lung surfactant increase annexin A7 localization with ABCA3 in alveolar type II cells.

Membrane fusion between the lamellar bodies and plasma membrane is an obligatory event in the secretion of lung surfactant. Previous studies have postulated a role for annexin A7 (A7) in membrane fusion during exocytosis in some cells including alveolar type II cells. However, the intracellular trafficking of A7 during such fusion is not described. In this study, we investigated association of endogenous A7 with lamellar bodies in alveolar type II cells following treatment with several secretagogues of lung surfactant. Biochemical studies with specific antibodies showed increased membrane-association of cell A7 in type II cells stimulated with agents that increase secretion through different signaling mechanisms. Immuno-fluorescence studies showed increased co-localization of A7 with ABCA3, the lamellar body marker protein. Because these agents increase surfactant secretion through activation of PKC and PKA, we also investigated the effects of PKC and PKA inhibitors, bisindolylmaleimideI (BisI) and H89, respectively, on A7 partitioning. Western blot analysis showed that these inhibitors prevented secretagogue-mediated A7 increase in the membrane fractions. These inhibitors also blocked increased co-localization of A7 with ABCA3 in secretagogue-treated cells, as revealed by immuno-fluorescence studies. In vitro studies with recombinant A7 showed phosphorylation with PKC and PKA. The cell A7 was also phosphorylated in cells treated with surfactant secretagogues. Thus, our studies demonstrate that annexin A7 relocates to lamellar bodies in a phosphorylation-dependent manner. We suggest that activation of protein kinase promotes phosphorylation and membrane-association of A7 presumably to facilitate membrane fusion during lung surfactant secretion.

Manual whole-cell patch-clamping of the HERG cardiac K+ channel.

Delayed ventricular repolarization, as measured by a prolongation of the QT interval on the electrocardiogram, is a major safety issue in the drug development process. It is now recognized that most cases of drug-induced QT prolongation arise from direct pharmacological inhibition of the human ether-a-go-go-related gene (HERG) cardiac K+ channel. It is standard practice to test a drug's ability to interact with the HERG channel prior to entry into clinical trials. This testing is used, as part of a larger battery of tests, to help predict the cardiac safety profile of a drug. Manual whole-cell patch-clamping provides the most sensitive and accurate way to examine the biophysical and pharmacological properties of the HERG cardiac K+ channel.