Early Stereotactic Body Radiotherapy to the Primary Lung Lesion for Patients with Advanced NSCLC Treated with First-Line Systemic Therapy

PURPOSE/OBJECTIVE(S)

Although adding consolidative stereotactic body radiotherapy (SBRT) to systemic therapy improves survival in advanced non-small cell lung cancer (NSCLC), the optimal timing of SBRT remains unclear. This study aimed to explore the clinical outcome of early and delayed SBRT to primary lung lesions of advanced NSCLC patients treated with first-line systemic therapy.

MATERIALS/METHODS

We identified patients with advanced NSCLC who were suitable to receiveSBRT for the primary lung tumors after first-line systemic therapy. All eligible patients were treated with first-line systemic therapy and SBRT for their primary lung lesions. Early SBRT group was defined as patients who received SBRT for their primary lung tumor at the maximal response of systemic therapy. Delayed SBRT group was defined as patients who received SBRT after the occurrence of oligoprogression in primary lung tumor. The primary endpoints were progression-free survival 1 (PFS1, time from start of first-line systemic therapy to disease progression) and PFS2 (time from start of first-line systemic therapy to disease progression after SBRT). Overall survival (OS) and adverse effects (AEs) were secondary endpoints. A two-sided P value of 0.05 was considered statistically significant. All of the statistical analyses were performed with statistical software.

RESULTS

A total of184 patients with advanced NSCLC treated with SBRT for primary tumors were screened, and 49 patients were eligible for enrollment in this study. The median age of the entire cohort was 66 years (range, 37-80 years), and 34 (69.4%) patients were male. Thirty-four patients (69.4%) were treated by target therapy and 15 (30.6%) were treated by chemotherapy and immunotherapy. Of the 49 eligible patients, 28(57.1%) received early SBRT to lung primary tumor and 21(42.9%) received delayed SBRT to lung primary tumor. The early SBRT group showed a significantly prolonged PFS1 as compared with the delayed SBRT group (mPFS1: 30 months vs. 8 months, P<0.001). The median PFS2 of the early SBRT group was longer than that of the delayed SBRT group, but the difference between the two groups did not achieve a statistical significance (mPFS2: 42 months vs. 23 months, P = 0.303). Median OS of both groups has not reached. No severe toxicities (≥grade 3) were observed in early SBRT group and only one patient in the delayed SBRT group experienced grade 3 radiation pneumonitis.

CONCLUSION

Early SBRT to the primary lung lesion significantly improved PFS and is a new potentially effective and tolerable treatment option for patients with advanced NSCLC who had stable disease during first-line systemic therapy.

[Associations of all-cause mortality with admission blood pressure variability during multiple hospitalizations in acute decompensated heart failure]

Objective: To investigate whether admission blood pressure (BP) variability during multiple hospitalizations is associated with all-cause mortality independent of baseline BP in acute decompensated heart failure (ADHF). Methods: Patients with ADHF admitted to the Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University from September 2013 to December 2017 were retrospectively enrolled. The risk of all-cause mortality associated with indices of BP variability, including mean admission BPs, standard deviation of BP and coefficient of variation of BP during multiple hospitalizations was assessed, using Cox regression model. Results: A total of 1 006 ADHF patients (mean aged (69.3±13.5) years; 411 (40.8%) female; 670 (66.6%) with preserved ejection fraction) were enrolled. During a median follow-up of 1.54 years, 47.0% of patients died. In all ADHF patients, after adjusting for confounding factors, for every 1-standard deviation (SD) increase in SD and coefficient of variation (CV) of systolic BP, the risk of all-cause mortality increased by 10% and 11%, respectively (SD: HR, 1.10, 95%CI, 1.01-1.21, P=0.029, CV: HR, 1.11, 95%CI, 1.02-1.21, P=0.017); for every 1-SD increase in the mean of diastolic BP, the risk of all cause mortality decreased by 25% (HR, 0.75; 95%CI, 0.65-0.87; P<0.001). In ADHF patients with preserved ejection fraction, after accounted for potential confounders, higher SD and CV of admitted systolic and diastolic BP were significantly associated with higher risk of all-cause mortality, regardless of whether confounding factors were adjusted (P≤0.049); After adjusting for confounding factors, the risk of all-cause mortality increased by 18% and 19% for every 1-SD increase in SD and CV of systolic BP, while the risk of all-cause mortality increased by 11% and 15% for every 1-SD increase in SD and CV of diastolic BP. In ADHF patients with reduced ejection fraction, after adjusting for confounding factors, the higher the mean admission systolic BP during multiple hospitalizations, the lower the risk of total mortality (HR, 0.68; 95%CI, 0.47-1.00; P=0.049). Conclusions: In patients with ADHF, independent of baseline BP, BP variability during multiple hospitalizations was strong predictor of all-cause mortality.

Coherent Picture on the Pure Spin Transport between Ag/Bi and Ferromagnets

In a joint effort of both experiments and first-principles calculations, we resolve a hotly debated controversy and provide a coherent picture on the pure spin transport between Ag/Bi and ferromagnets. We demonstrate a strong inverse Rashba-Edelstein effect (IREE) at the interface in between Ag/Bi with a ferromagnetic metal (FM) but not with a ferromagnetic insulator. This is in sharp contrast to the previously claimed IREE at Ag/Bi interface or inverse spin Hall effect dominated spin transport. A more than one order of magnitude modulation of IREE signal is realized for different Ag/Bi-FM interfaces, casting strong tunability and a new direction for searching efficient spintronics materials.

[Efficacy and safety of carotid endarterectomy combined with endovascular therapy in hybrid operating room for patients with segmental atherosclerotic internal carotid artery occlusion]

The current study aimed to investigate the efficacy and safety of carotid endarterectomy combined with endovascular therapy in hybrid operating room for patients with segmental atherosclerotic internal carotid artery occlusion, and share the experience of preoperative screening of patients suitable for vascular reconstruction. A total of 20 patients with internal carotid artery occlusion (ICAO) who were admitted to the Department of Neurosurgery, General Hospital of Tianjin Medical University from May 2018 to May 2020 were collected, and 15 patients met the inclusion criteria. All patients received hybrid surgery. The total success rate of recanalization was 14/15, and only 1 patient developed ICA re-occlusion at 1 year follow up.Therefore, carotid endarterectomy combined with endovascular treatment in hybrid operating room was an alternative treatment for patients with segmental atherosclerotic internal carotid artery occlusion.

[Investigation and analysis of a mass ammonia gas poisoning accident]

Objective: To investigation and analysis of ammonia gas leakage in a meat factory. Methods: In April 2013, Enterprise managers and workers were investigated, and clinical data of 24 patients were analyzed. Results: The company caused a leak in the ammonia pipeline maintenance operation, Among the patients, 20 had stimulus response and 4 had mild poisoning. Conclusion: To prevent group occupational ammonia poisoning, it is necessary to strengthen the awareness of occupational disease prevention of enterprise owners and the awareness of self-protection of workers.

Magnetic Hamiltonian parameter estimation using deep learning techniques

Understanding spin textures in magnetic systems is extremely important to the spintronics and it is vital to extrapolate the magnetic Hamiltonian parameters through the experimentally determined spin. It can provide a better complementary link between theories and experimental results. We demonstrate deep learning can quantify the magnetic Hamiltonian from magnetic domain images. To train the deep neural network, we generated domain configurations with Monte Carlo method. The errors from the estimations was analyzed with statistical methods and confirmed the network was successfully trained to relate the Hamiltonian parameters with magnetic structure characteristics. The network was applied to estimate experimentally observed domain images. The results are consistent with the reported results, which verifies the effectiveness of our methods. On the basis of our study, we anticipate that the deep learning techniques make a bridge to connect the experimental and theoretical approaches not only in magnetism but also throughout any scientific research.

Creation of skyrmions in van der Waals ferromagnet Fe3GeTe2 on (Co/Pd) n superlattice

Magnetic skyrmions are topological spin textures, which usually exist in noncentrosymmetric materials where the crystal inversion symmetry breaking generates the so-called Dzyaloshinskii-Moriya interaction. This requirement unfortunately excludes many important magnetic material classes, including the recently found two-dimensional van der Waals (vdW) magnetic materials, which offer unprecedented opportunities for spintronic technology. Using photoemission electron microscopy and Lorentz transmission electron microscopy, we investigated and stabilized Néel-type magnetic skyrmion in vdW ferromagnetic Fe₃GeTe₂ on top of (Co/Pd) _n in which the Fe₃GeTe₂ has a centrosymmetric crystal structure. We demonstrate that the magnetic coupling between the Fe₃GeTe₂ and the (Co/Pd) _n could create skyrmions in Fe₃GeTe₂ without the need of an external magnetic field. Our results open exciting opportunities in spintronic research and the engineering of topologically protected nanoscale features by expanding the group of skyrmion host materials to include these previously unknown vdW magnets.

[Comparison of heart failure and COVID-19 in chest CT features and clinical characteristics]

Objective: To identify the characteristics including clinical features and pulmonary computed tomography (CT) features of heart failure and COVID-19. Methods: This study was a retrospective study. A total of 7 patients with heart failure and 12 patients with COVID-19 in the Second Xiangya Hospital of Central South University between December 1, 2019 and February 15, 2020 were enrolled. The baseline clinical and imaging features of the two groups were statistically analyzed. Results: There was no significant difference in age and sex between the two groups(both P>0.05), but the incidence of epidemiological contact history, fever or respiratory symptoms in the COVID-19 group was significantly higher than that in the heart failure group (12/12 vs. 0, P<0.001; 12/12 vs. 4/7, P=0.013). While the proportion of cardiovascular diseases and impaired cardiac function was significantly less than that of the heart failure group(2/12 vs.7/7, P<0.001；0 vs.7/7, P<0.001). For imaging features, both groups had ground-glass opacity and thickening of interlobular septum, but the ratio of central and gradient distribution was higher in patients with heart failure than that in patients with COVID-19 (4/7 vs. 1/12, P=0.04). In heart failure group, the ratio of the expansion of pulmonary veins was also higher (3/7 vs. 0，P=0.013), and the lung lesions can be significantly improved after effective anti-heart failure treatment. Besides, there were more cases with rounded morphology in COVID-19 group（9/12 vs. 2/7, P=0.048）. Conclusions: More patients with COVID-19 have epidemiological history and fever or respiratory symptoms. There are significant differences in chest CT features, such as enlargement of pulmonary veins, lesions distribution and morphology between heart failure and COVID-19.

Intrinsic Mechanism for Anisotropic Magnetoresistance and Experimental Confirmation in Co_{x}Fe_{1-x} Single-Crystal Films

Using first-principles transport calculations, we predict that the anisotropic magnetoresistance (AMR) of single-crystal Co_{x}Fe_{1-x} alloys is strongly dependent on the current orientation and alloy concentration. An intrinsic mechanism for AMR is found to arise from the band crossing due to magnetization-dependent symmetry protection. These special k points can be shifted towards or away from the Fermi energy by varying the alloy composition and hence the exchange splitting, thus allowing AMR tunability. The prediction is confirmed by delicate transport measurements, which further reveal a reciprocal relationship of the longitudinal and transverse resistivities along different crystal axes.

Fast and deterministic switching of a vortex core induced by an out-of-plane current in notch disks

The magnetic vortex, as one of the most interesting magnetic solitons, has attracted great interest over the past two decades. A fast and reliable method to switch vortex polarity and chirality is one of the key issues for various applications. Based on micromagnetic simulation, here we report a fast, low energy cost and deterministic switching of a vortex core, by the designing of a notch structure in disks and the use of out-of-plane current geometry. We demonstrate that with such a design, the multiple switching problems found in notch disk systems can be avoided. Furthermore, the switching time can be reduced by more than 50% compared with disks without notches.

[Mechanism of transcriptional regulation of Meox1 by transforming growth factor β (1) and its effect on cell migration of adult human dermal fibroblasts]

Objective: To explore the transcriptional regulation mechanism of transforming growth factor β(1) (TGF-β(1)) on Meox1 and its effect on cell migration of adult human dermal fibroblasts (HDF-a). Methods: (1) HDF-a cells were cultured in RPMI 1640 complete medium (hereinafter referred to as routinely cultured). The cells were divided into TGF-β(1) stimulation group and blank control group. The cells in TGF-β(1) stimulation group were stimulated with 10 μL TGF-β(1) in the mass concentration of 1 mg/μL, while the cells in blank control group were stimulated with the equal volume of phosphate buffer solution. After 72 hours in culture, partial cells in both groups were collected for transcriptome sequencing. The genes with differential expression ratio greater than or equal to 2 and P<0.01 between the two groups were selected to perform enrichment analysis and analysis of metabolic pathways of the Kyoto Gene and Genome Encyclopedia with, and the expression value of Meox1 per million transcripts (TPM) was recorded (n=3). Partial cells from the two groups were used to detect the Meox1 mRNA expression by real-time fluorescent quantitative reverse transcription polymerase chain reaction (RT-PCR) (n=3). (2) Cultured HDF-a cells in the logarithmic growth phase (the same growth phase of cells below) were divided into empty plasmid group, Smad2 overexpression (OE) group, Smad3 OE group, and Smad4 OE group, which were transfected respectively with 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmids separately carrying Smad2, Smad3, and Smad4 for 6 hours, and then were routinely cultured for 48 hours. The Meox1 mRNA expression in the transfected cells of each group was detected by real-time fluorescent quantitative RT-PCR (n=3). (3) HDF-a cells were routinely cultured and grouped the same as in experiment (1). After 72 hours in culture, the enrichment of Smad2, Smad3, and Smad4 protein on the Meox1 promoter in the cells of each group was detected by chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) (n=3). (4) HDF-a cells were routinely cultured and divided into negative interference group, small interference RNA (siRNA)-Smad2 group, siRNA-Smad3 group, siRNA-Smad4 group, empty plasmid group, Smad2 OE group, Smad3 OE group, and Smad4 OE group, which were transfected respectively with 50 μmol/L random siRNA, siRNA-Smad2, siRNA-Smad3, siRNA-Smad4, 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmids separately carrying Smad2, Smad3, and Smad4 for 6 hours and then routinely cultured for 48 hours. The enrichment of Smad2, Smad3, and Smad4 protein on the Meox1 promoter in the cells of corresponding group was detected by ChIP-qPCR (n=3). (5) Two batches of HDF-a cells were cultured and divided into negative interference group, siRNA-Meox1 group, empty plasmid group, and Meox1 OE group, which were transfected respectively with 50 μmol/L random siRNA, siRNA-Meox1, 2 μg empty pcDNA3.1 plasmid and pcDNA3.1 plasmid carrying Meox1 for 6 hours and then routinely cultured for 24 hours. One batch of cells were subjected to scratch test with the scratch width being observed 24 hours after scratching and compared with the initial width for scratch wound healing; the other batch of cells were subjected to Transwell assay, in which the migrated cells were counted after being routinely cultured for 24 hours (n=3). (6) From January 2018 to June 2019, 3 hypertrophic scar patients (2 males and 1 female, aged 35-56 years) were admitted to the First Affiliated Hospital of Army Medical University (the Third Military Medical University) 8-12 months after burns. The scar tissue and normal skin tissue along the scar margin resected during surgery were taken, and immunohistochemical staining was performed to observe the distribution of Meox1 protein expression. Data were statistically analyzed with one-way analysis of variance and independent sample t test. Results: (1) After 72 hours in culture, a total of 843 genes were obviously differentially expressed between the two groups, being related to tissue repair, cell migration, inflammatory cell chemotaxis induction process and potential signaling pathways such as tumor necrosis factor, interleukin 17, extracellular matrix receptor. The TPM value of Meox1 in the cells of blank control group was 45.9±1.9, which was significantly lower than 163.1±29.5 of TGF-β(1) stimulation group (t=6.88, P<0.01) with RNA-sequencing. After 72 hours in culture, the Meox1 mRNA expression levels in the cells of blank control group was 1.00±0.21, which was significantly lower than 11.00±3.61 of TGF-β(1) stimulation group (t=4.79, P<0.01). (2) After 48 hours in culture, the Meox1 mRNA expression levels in the cells of Smad2 OE group, Smad3 OE group, and Smad4 OE group were 198.70±11.02, 35.47±4.30, 20.27±2.50, respectively, which were significantly higher than 1.03±0.19 of empty plasmid group (t=31.07, 13.80, 13.12, P<0.01). (3) After 72 hours in culture, the enrichment of Smad2, Smad3, and Smad4 protein on the promoter of Meox1 in the cells of TGF-β(1) stimulation group was significantly higher than that of blank control group respectively (t=12.99, 41.47, 29.10, P<0.01). (4) After 48 hours in culture, the enrichment of Smad2 protein on the promoter of Meox1 in the cells of negative interference group was (0.200 000±0.030 000)%, significantly higher than (0.000 770±0.000 013)% of siRNA-Smad2 group (t=11.67, P<0.01); the enrichment of Smad2 protein on the promoter of Meox1 in the cells of empty plasmid group was (0.200 000±0.040 000)%, significantly lower than (0.700 000±0.090 000)% of Smad2 OE group (t=8.85, P<0.01). The enrichment of Smad3 protein on the promoter of Meox1 in the cells of negative interference group was (0.500 0±0.041 3)%, significantly higher than (0.006 0±0.001 3)% of siRNA-Smad3 group (t=17.79, P<0.01); the enrichment of Smad3 protein on the promoter of Meox1 in the cells of empty plasmid group was (0.470 0±0.080 0)%, which was significantly lower than (1.100 0±0.070 0)% of Smad3 OE group (t=9.93, P<0.01). The enrichment of Smad4 protein on the promoter of Meox1 in the cells of negative interference group was similar to that of siRNA-Smad4 group (t=2.11, P>0.05); the enrichment of Smad4 protein on the promoter of Meox1 in the cells of empty plasmid group was similar to that of Smad4 OE group (t=0.60, P>0.05). (5) Twenty-four hours after scratching, the scratch healing width of cells in siRNA-Meox1 group was narrower than that of negative interference group, while that of Meox1 OE group was wider than that of empty plasmid group. After 24 hours in culture, the number of migration cells in negative interference group was significantly higher than that in siRNA-Meox1 group (t=9.12, P<0.01), and that in empty plasmid group was significantly lower than that in Meox1 OE group (t=8.99, P<0.01). (6) The expression of Meox1 protein in the scar tissue was significantly higher than that in normal skin of patients with hypertrophic scars. Conclusions: TGF-β(1) transcriptionally regulates Meox1 expression via Smad2/3 in HDF-a cells, thus promoting cell migration.

[The experimental study of diquat on the half-Lethal dose and pothological injuny of related organs in wistor rats]

Objective: To explore the acute toxicity of Diquat in mice and to calculate the median lethal dose (LD(50)) of Diquat to rats and observe the pathological changes of tissues and organs in rats with different concentrations of Diquat. Methods: Diquat solution of 50 mg/kg was prepared freshly with 1 000 mg of Diquat and dilute the solution with water to a total of 20 ml. A total of 99 healthy adult male Wistar rats were randomly divided into part one, part two and control groups. In the first part, 36 rats were randomly divided into 4 groups: 100 mg/kg group, 200 mg/kg group, 300 mg/kg group and 400 mg/kg group, which were treated with 100 mg/kg, 200 mg/kg, 300 mg/kg and 400 mg/kg of Diquat solution by gavage, respectively. The death and symptoms of poisoning after intragastric administration were recorded, and the maximum tolerated dose and absolute lethal dose were measured. In the second part, 54 rats were randomly divided into 6 groups: 200 mg/kg group, 220 mg/kg group, 240 mg/kg group, 260 mg/kg、280 mg/kg group and 300 mg/kg group, whichwere treated with 200 mg/kg, 220 mg/kg, 240 mg/kg, 260 mg/kg, 280 mg/kg and 300 mg/kg of Diquat solution by gavage, respectively. The survival of rats in different concentration of Diquat was observed and the LD(50) was calculated by Excel processing the formula of Koch's method. The control group were given equal volume water under the same experimental conditions. And moreover, the lungs, kidneys, hearts, livers, and brain tissues were collected and fixed by formaldehyde, embedded by paraffin, and sectioned for histopathological light microscopy. Results: The maximum tolerated dose was 240 mg/kg and the absolute lethal dose was 300 mg/kg. The LD(50) of Diquat for Rats was 280.58 mg/kg. The high-dose group had significantly more organ damage than the low-dose group after diquat poisoning. Conclusion: The determination of the half-lethal dose of diquat, at the same time observed multiple organs damaged in rats after the diquat quickly poisoned. Kidneys, lungs and heart might be the main organ which was heavily damaged. With the extension of observation time, the organ damage of rats exposed to small doses gradually stabilized.

[Observation and prevention measures against adverse reaction to intratympanic corticosteroid injections]

Objective:To investigate clinical characteristic and incidence of the adverse reaction to tympanic injection. The incidence rates of adverse reaction were also compared after improvement of anesthetic method and changed ratio of methylprednisolone. Method: A retrospective analysis of 712 cases (1 928 injections) of receiving injection in a medical center, to explore the overall and classified adverse reactions, as well as effects of age and gender and frequency on adverse reactions. According to the clinical characteristics of the early stage, the incidence of adverse reaction was observed after the application of anesthesia warming method and the change of methylprednisolone ratio. Result: Adverse reaction was found in 76 cases which included 62 cases of mild reactions, 4 cases of severe reactions and 10 cases of glucocorticoid-related reactions. Overall, 10.67% of patients had adverse reactions. There was no correlation between adverse reactions and age, gender or frequency. The incidence of vertigo was decreased after the application of improved anesthesia (P<0.05). The incidence of pain of joint methylprednisolone-and-lidocaine injection was lower than that of methylprednisolone injection (P<0.05). Conclusion: Intratympanic injection is a safe treatment, to some extent, although there is low incidence of adverse effects of it. At the same time, anesthetic warming method and changing the ratio of methylprednisolone can further reduce the incidence of vertigo and pain.

Broadband Terahertz Generation via the Interface Inverse Rashba-Edelstein Effect

Novel mechanisms for electromagnetic wave emission in the terahertz frequency regime emerging at the nanometer scale have recently attracted intense attention for the purpose of searching next-generation broadband THz emitters. Here, we report broadband THz emission, utilizing the interface inverse Rashba-Edelstein effect. By engineering the symmetry of the Ag/Bi Rashba interface, we demonstrate a controllable THz radiation (∼0.1-5  THz) waveform emitted from metallic Fe/Ag/Bi heterostructures following photoexcitation. We further reveal that this type of THz radiation can be selectively superimposed on the emission discovered recently due to the inverse spin Hall effect, yielding a unique film thickness dependent emission pattern. Our results thus offer new opportunities for versatile broadband THz radiation using the interface quantum effects.

[A group of occupational acute methyl bromide poisoning incident]

Objective: To investigate a mass of occupational acute methyl bromide poisoning incident and analyzed their clinical data. Methods: To investigate an incident a mass of occupational acute methyl bromide poisoning in occurred in Shandong province in November 2016, and the clinical datas of 3 cases of severe patients with methyl bromide poisoning were analysed. Results: This event was a sudden occupational poisoning incident. Lack of vocational training and irregularities is the main reason for the accident 3 patients with nervous system, respiratory system, circulatory system, urinary system damage is given priority to, after comprehensive rescue treatment, 2 cases died and 1 case survived. Conclusions: Methyl bromide can cause severe poisoning, has high mortality in patients with acute severe poisoning.

Ultrafast spin exchange-coupling torque via photo-excited charge-transfer processes

Optical control of spin is of central importance in the research of ultrafast spintronic devices utilizing spin dynamics at short time scales. Recently developed optical approaches such as ultrafast demagnetization, spin-transfer and spin-orbit torques open new pathways to manipulate spin through its interaction with photon, orbit, charge or phonon. However, these processes are limited by either the long thermal recovery time or the low-temperature requirement. Here we experimentally demonstrate ultrafast coherent spin precession via optical charge-transfer processes in the exchange-coupled Fe/CoO system at room temperature. The efficiency of spin precession excitation is significantly higher and the recovery time of the exchange-coupling torque is much shorter than for the demagnetization procedure, which is desirable for fast switching. The exchange coupling is a key issue in spin valves and tunnelling junctions, and hence our findings will help promote the development of exchange-coupled device concepts for ultrafast coherent spin manipulation.

Light can provide ultrafast ways of spin manipulation in magnetic materials, but existing methods are limited by long thermal recovery or low temperature. Here, the authors demonstrate ultrafast spin precession via optical charge-transfer processes in exchange-coupled Fe/CoO at room temperature.

Quantitative study of the quadratic magneto-optical Kerr effects in Fe films

We present a rotating field method to separate the linear and quadratic magneto-optical Kerr effects (LMOKE and QMOKE) in Fe/GaAs(001) films. The LMOKE is isotropic in crystal orientation, while the QMOKE has both isotropic and anisotropic contributions. The experimental observation is well explained by Yeh's 4×4 matrix formalism. We also report the incident angle and the thickness dependences of the LMOKE and QMOKE, and extract the material's index of refraction n and the magneto-optical coupling constant K and G. The study gives a full description of the Kerr effect in Fe films, and the proposed method can be applied to other magneto-optical coupling systems.

Comparative analysis of mucosal immunity to Mycoplasma hyopneumoniae in Jiangquhai porcine lean strain and DLY piglets

The Jiangquhai porcine lean strain (JQHPL) is a new pork meat-type strain that has been developed in recent years from the parent lines Duroc, Fengjing, and Jiangquhai pigs (DurocxFengjing pigxJiangquhai pig). Enzootic pneumonia (EP) in pigs induced by Mycoplasma hyopneumoniae (M. hyopneumoniae) is a chronic respiratory disease of pigs, generating high economic losses in the swine industry. Here, we investigated the degree of resistance to M. hyopneumoniae for the Jiangquhai porcine lean strain and the Duroc x Landrace x Yorkshire (DLY) pigs, which are Western commercial pigs that have been introduced in China. A total of 209 DLY piglets and 221 JQHPL piglets from 19 Landrace x Yorkshire and 22 JQHPL M. hyopneumoniae positive gestating sows with different expected dates of confinement were selected and raised in the same M. hyopneumoniae positive farrowing barn. When the oldest suckling piglets were 37 days old, nasal swabs were collected from all the piglets (ranging from 4 to 37 days old) to detect the M. hyopneumoniae pathogen using n-PCR and M. hyopneumoniae specific SIgA using ELISA. Positive M. hyopneumoniae infection rates in both the strains increased with age; however, positive rates for JQHPL were lower compared to DLY at 14 to 35 days old. The level of the specific SIgA rose rapidly in JQHPL respiratory tracts, particularly in piglets 21 to 35 days in age compared to DLY piglets of the same age; however, the level of the specific SIgA in DLY also marginally increased. In conclusion, JQHPL pigs exhibits higher resistance to M. hyopneumoniae compared to DLY. It is possible that this characteristic is caused by the faster and stronger mucosal immunity phenotype of the JQHPL strain.

RASSF6 promotes p21(Cip1/Waf1)-dependent cell cycle arrest and apoptosis through activation of the JNK/SAPK pathway in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a highly aggressive and common pathological subtype of renal cancer. This cancer is characterized by biallelic inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene, which leads to the accumulation of hypoxia-inducible factors (HIFs). Although therapies targeted at HIFs can significantly improve survival, nearly all patients with advanced ccRCC eventually succumb to the disease. Thus, additional oncogenic events are thought to be involved in the development of ccRCC tumors. In this study, we investigated the role of RASSF6 in ccRCC. Downregulation of RASSF6 was commonly observed in primary tumors relative to matched adjacent normal tissues. Moreover, functional studies established that ectopic re-expression of RASSF6 in ccRCC cells inhibited cell proliferation, clonogenicity, and tumor growth in mice, whereas silencing of RASSF6 dramatically enhanced cell proliferation in vitro and in vivo. Mechanistic investigation suggested that RASSF6 triggers p21(Cip1/Waf1) accumulation to induce G 1 cell cycle arrest and promote apoptosis upon exposure to pro-apoptotic agents, and both of these mechanisms appear to be mediated by activated JNK signaling. Together, these findings suggest that RASSF6 may play a tumor suppressor role in the progression of ccRCC.

Novel chiral magnetic domain wall structure in Fe/Ni/Cu(001) films

Using spin-polarized low energy electron microscopy, we discovered a new type of domain wall structure in perpendicularly magnetized Fe/Ni bilayers grown epitaxially on Cu(100). Specifically, we observed unexpected Néel-type walls with fixed chirality in the magnetic stripe phase. Furthermore, we find that the chirality of the domain walls is determined by the film growth order with the chirality being right handed in Fe/Ni bilayers and left handed in Ni/Fe bilayers, suggesting that the underlying mechanism is the Dzyaloshinskii-Moriya interaction at the film interfaces. Our observations may open a new route to control chiral spin structures using interfacial engineering in transition metal heterostructures.

Electric-field control of nonvolatile magnetization in Co40Fe40B20/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O3 structure at room temperature

We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a Co(40)Fe(40)B(20)/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O(3) structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in Co(40)Fe(40)B(20). This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.

Direct measurement of rotatable and frozen CoO spins in exchange bias system of CoO/Fe/Ag(001)

The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using x-ray magnetic circular dichroism and x-ray magnetic linear dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film. We further show that the rotatable and frozen CoO spins are uniformly distributed in the CoO film.

Quantum-well states in a double-well system: an example of Cu/Co(Ni)/Cu

The quantum-well (QW) states in the Cu/Co double-well system are studied by first-principles calculations. We have shown that the monolayer Ni or Co as a heterogeneous spacer in Cu QW can not only disturb the QW states extending into the whole structure, but also create new QW states because of the interfaces introduced, resulting in sub-well-confining electrons. If the QW state energy in two sub-wells is close to each other, these two sub-well QW states can couple together. We have also demonstrated that monolayer Co and Ni spacers play different roles for modulating QW states at different energy levels, which also result in a complicated distribution of QW states. The obtained results are in good agreement with experiment data.

Oscillatory magnetic anisotropy originating from quantum well states in Fe films

The magnetic anisotropy of Fe film grown on vicinal Ag(1,1,10) surfaces was studied with the in situ magneto-optic Kerr effect. Below 200 K, strong oscillations of the uniaxial magnetic anisotropy as a function of Fe thickness with a period of 5.7 monolayers are found, which can even cause the easy magnetization axis to oscillate between perpendicular and parallel to the steps. Such novel oscillation of the anisotropy is attributed to the quantum well states of d-band electrons at the Fermi level in the Fe film. This is unlike the previously observed oscillatory behaviors of ferromagnetic films caused by the quantum well states in nonmagnetic interfacing layers.

[Serum levels of sVCAM-1, IL-18 and VEGF in patients with aplastic anemia and their clinical significance]

This study was purposed to investigate the serum levels of soluble intracellular adhesion molecule (sVCAM-1), interleukin 18 (IL-18) and vascular endothelial growth factor (VEGF) in patients with aplastic anemia (AA) and their clinical significance. Enzyme linked immunosorbent assay (ELISA) was used to detect sVCAM-1, IL-18 and VEGF in serums of 30 patients with AA and 25 normal controls. The results showed that the serum levels of sVCAM-1 and IL-18 in patients with AA [(839.08 +/- 173.97) ng/ml, (380.35 +/- 47.76) pg/ml] were significantly higher than those in normal controls [(538.16 +/- 91.21) ng/ml, (256.39 +/- 59.52) pg/ml] (p < 0.01; p < 0.01). The levels of sVCAM-1 and IL-18 in severe AA patients [(969.94 +/- 182.54) ng/ml, (388.96 +/- 46.06) pg/ml] were higher than those in chronic AA patients [(709.26 +/- 165.32) ng/ml, IL-18 (352.21 +/- 47.08) pg/ml] (p < 0.01; p < 0.05), but the level of VEGF in AA patients [(69.63 +/- 27.42) pg/ml] was lower than that in the normal controls [(125.62 +/- 32.15) pg/ml] (p < 0.01)]. The level of VEGF in severe AA patients [(51.30 +/- 29.86) pg/ml] was significantly lower than that in chronic AA patients [(80.02 +/- 25.14) pg/ml] (p < 0.01). The levels of sVCAM-1 and IL-18 in AA patients after treatment were lower than those before treatment (p < 0.01; p < 0.05), but the level of VEGF after treatment was significantly higher than that before treatment (p < 0.05). It is concluded that the high levels of sVCAM-1, IL-18 and low level of VEGF in serum may be involved in the pathogenesis and progress of AA.

Symmetry-breaking induced exchange bias in ferromagnetic Ni-Cu-Co and Ni-Fe-Co sandwiches grown on a vicinal Cu(001) surface

Ferromagnetic Ni-Cu-Co and Ni-Fe-Co sandwiches were grown epitaxially onto a vicinal Cu(001) substrate and investigated using magneto-optical Kerr effect and x-ray magnetic circular dichroism techniques. We find that the atomic steps of the vicinal surface break the magnetic reversal symmetry to induce an exchange bias in the Ni perpendicular magnetic hysteresis loop. The Ni exchange bias direction can be switched by changing the direction of the in-plane Co magnetization. In addition, the exchange bias can be tailored by changing the Cu or Fe spacer layer thickness.

Magnetic bubble domain phase at the spin reorientation transition of ultrathin Fe/Ni/Cu(001) film

Magnetic domain phases of ultrathin Fe/Ni/Cu(001) are studied using photoemission electron microscopy at the spin reorientation transition (SRT). We observe a new magnetic phase of bubble domains within a narrow SRT region after applying a nearly in-plane magnetic field pulse to the sample. By applying the magnetic field pulse along different directions, we find that the bubble domain phase exists only if the magnetic field direction is less than approximately 10 degrees relative to the sample surface. A temperature dependent measurement shows that the bubble domain phase becomes unstable above 370 K.

Spin-dependent quantum interference from epitaxial MgO thin films on Fe(001)

Spin-dependent electron reflection from MgO thin films grown on Fe(001) was measured using spin-polarized low energy electron microscopy. The electron reflectivity exhibits quantum interference from which two MgO energy bands with Delta1 symmetry were determined in experiment. We found that a bulklike MgO energy gap is fully established for MgO film thicker than 3 atomic monolayers and that the electron reflectivity from the MgO/Fe interface exhibits a spin-dependent amplitude and a spin-independent phase change.

Body-centered-cubic Ni and its magnetic properties

The body-centered-cubic (bcc) phase of Ni, which does not exist in nature, has been achieved as a thin film on GaAs(001) at 170 K via molecular beam epitaxy. The bcc Ni is ferromagnetic with a Curie temperature of 456 K and possesses a magnetic moment of 0.52+/-0.08 micro(B)/atom. The cubic magnetocrystalline anisotropy of bcc Ni is determined to be +4.0x10(5) ergs x cm(-3), as opposed to -5.7x10(4) ergs x cm(-3) for the naturally occurring face-centered-cubic (fcc) Ni. This sharp contrast in the magnetic anisotropy is attributed to the different electronic band structures between bcc Ni and fcc Ni, which are determined using angle-resolved photoemission with synchrotron radiation.

Spin-dependent Fabry-Pérot interference from a Cu thin film grown on fcc Co(001)

Spin-dependent electron reflection from a Cu thin film grown on Co/Cu(001) was investigated using spin-polarized low-energy electron microscopy (SPLEEM). Fabry-Pe rot type interference was observed and is explained using the phase accumulation model. SPLEEM images of the Cu overlayer reveal magnetic domains in the Co underlayer, with the domain contrast oscillating with electron energy and Cu film thickness. This behavior is attributed to the spin-dependent electron reflectivity at the Cu/Co interface which leads to spin-dependent Fabry-Pe rot electron interference in the Cu film.

Magnetic stripe domains in coupled magnetic sandwiches

Magnetic stripe domains in the spin reorientation transition region are investigated in (Fe/Ni)/Cu(001) and Co/Cu/(Fe/Ni)/Cu(001) using photoemission electron microscopy. For (Fe/Ni)/Cu(001), the stripe domain width decreases exponentially as the Fe/Ni film approaches the spin reorientation transition point. For Co/Cu/(Fe/Ni)/Cu(001), the Fe/Ni stripe orientation is aligned with the Co in-plane magnetization, and the stripe domain width decreases exponentially with increasing the interlayer coupling between the Fe/Ni and Co films. By considering magnetic stripes within an in-plane magnetic field, we reveal a universal dependence of the stripe domain width on the magnetic anisotropy and on the interlayer coupling.

Magnetic phase transition in Co/Cu/Ni/Cu(100) and Co/Fe/Ni/Cu(100)

Magnetic phase transitions in coupled magnetic sandwiches of Cu/Co/Cu/Ni/Cu(100) and Cu/Co/Fe/Ni/Cu(100) are investigated by photoemission electron microscopy. Element-specific magnetic domains are taken at room temperature to reveal the critical thickness at which the magnetic phase transition occurs. The results show that a coupled magnetic sandwich undergoes three types of magnetic phase transitions depending on the two ferromagnetic films' thickness. A phase diagram is constructed and explained in the process of constructing Monte Carlo simulations, which corroborate the experimental results.

The simulation of 31P NMR line shapes of lipid bilayers using an analytically soluble model

Van Faassen's method for obtaining an explicit solution to a first order stochastic differential equation is applied to the simulation of 31P NMR line shapes of unoriented phospholipid bilayers in the Lalpha phase and of oriented bilayers in both the Lalpha and Lbeta' phases. The effects of the two slowest motions on the density matrix are described by the stochastic Liouville equation (SLE) which is solved analytically using the method of van Faassen. These two slowest motions are assumed to be a rotational re-orientation about the long molecular axis and a uniform wobble of this axis within a conical volume with re-orientation rates characterised by correlation times tau(parallel) and tau(perpendicular) respectively. In the present work the Hamiltonian contains the intramolecular dipole-dipole interaction between the phosphorous nucleus and the four closest methylene protons of the choline headgroup, as well as the anisotropic chemical shielding interaction. Hence the contribution to relaxation from cross correlation between the dipole-dipole and anisotropic chemical shielding interactions is included. The reorientation of the headgroup is assumed to be a rotation sufficiently fast to lead to complete axially symmetric averaging of the Hamiltonian about the rotational axis (the P-O11 bond axis). Evaluation of the line shape in the present work involves only numerical integration and is therefore less computationally demanding than the large matrix inversions involved in the approaches of Campbell, Freed et al. The present theory also uses fewer parameters than that of Dufourc et al. but nevertheless results in good agreement with these authors' measurements on DMPC bilayers, using a fixed value of 10 for the ratio tau(perpendicular)/tau(parallel) in the case of the Lalpha phase. However, in contrast to Dufourc et al., we find that these correlation times are equal for the Lbeta' phase. Finally, we have simulated the decoupled powder line shapes obtained from the Lbeta' phase of DPPC by Campbell and Meirovitch. Again, we get good agreement providing tau(perpendicular)=tau(parallel).

Secondary sulphonylurea failure: what pathogenesis is responsible?

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.

[LC/MS research on the isomers of special melanoma antigen-encoding gene-2 epitope peptide induced by solvent]

To study the influence of different solvent systems on the isomers of melanoma antigen-encoding gene-2(MAGE-2) epitope peptide synthesized by Marrifield's solid synthesis method, MAGE-2(171-179) epitope peptides were pre-treated using ethanol and methanol systems respectively, and then analysed by RP-HPLC/MS, with dimethyl-sulphoxide (DMSO) as control solvent. Results demonstrated that 100% ethanol and 100% methanol solvents could induce the production of isomers of MAGE-2, while 100% DMSO, 50% ethanol and 50% methanol could not. These isomeric peptides could be reversed greatly if treated with trifluoroacetic acid (TFA). The results also showed that the analysis would be distorted and the yield of peptides would decrease dramatically if the peptides were pre-treated with high concentrations of ethanol and methanol before RP-HPLC analysis and preparation. Thus it is suggested that it might be better to decrease the concentration of organic phase in the solvent system for the resolvable hydrophobic peptides, acidified ethanol and methanol might also be better for the highly hydrophobic peptides, and DMSO would be a good solvent for hydrophobic peptides analysis provided that it would not influence the resolving power of chromatography.

[CT diagnosis of maxillary mucoceles]

CT signs of thirty-six cases of maxillary mucocele surgically and pathologically proved were analyzed. 20 of 36 cases revealed as low density lesion. 16 of 36 cases revealed as isodensity or high density lesion. They were morphologically classified as three types: nodular type, inflammatory type, bony defect type. Cystic morphology and fluid density within the lesion obviously indicated mucocele. Differential diagnosis should be made between mucocele and polyps, when the lesion revealed as soft tissue density. Inflammatory type need to be distinguished from maxillary inflammation. And bony defect type should be distinguished from the benign or malignant tumor of maxillary sinus. The islet sign and bone sclerosis are considered to be valuable for the differential diagnosis.

[CT diagnosis of hemorrhagic renal cysts]

CT signs of nineteen cases of hemorrhagic renal cysts that surgically and pathologically proved were analyzed. 8 of the 19 cases revealed as high density hemorrhagic lesion. CT signs in those 8 patients include low density rim sign, cyst immerging sign, and perirenal fascia thickening. The other 11 of 19 cases revealed as low density lesion. CT signs include thickened cyst wall and inhomogeneous density of the cystic content. The hounsfield unit of the lesion is correlated with the duration of disease. It is suggested that CT is valuable in diagnosis of high density hemorrhagic renal cysts, and it gives a clue to the diagnosis of low density hemorrhagic renal cysts.

Indirubins inhibit glycogen synthase kinase-3 beta and CDK5/p25, two protein kinases involved in abnormal tau phosphorylation in Alzheimer's disease. A property common to most cyclin-dependent kinase inhibitors?

The bis-indole indirubin is an active ingredient of Danggui Longhui Wan, a traditional Chinese medicine recipe used in the treatment of chronic diseases such as leukemias. The antitumoral properties of indirubin appear to correlate with their antimitotic effects. Indirubins were recently described as potent (IC(50): 50-100 nm) inhibitors of cyclin-dependent kinases (CDKs). We report here that indirubins are also powerful inhibitors (IC(50): 5-50 nm) of an evolutionarily related kinase, glycogen synthase kinase-3beta (GSK-3 beta). Testing of a series of indoles and bis-indoles against GSK-3 beta, CDK1/cyclin B, and CDK5/p25 shows that only indirubins inhibit these kinases. The structure-activity relationship study also suggests that indirubins bind to GSK-3 beta's ATP binding pocket in a way similar to their binding to CDKs, the details of which were recently revealed by crystallographic analysis. GSK-3 beta, along with CDK5, is responsible for most of the abnormal hyperphosphorylation of the microtubule-binding protein tau observed in Alzheimer's disease. Indirubin-3'-monoxime inhibits tau phosphorylation in vitro and in vivo at Alzheimer's disease-specific sites. Indirubins may thus have important implications in the study and treatment of neurodegenerative disorders. Indirubin-3'-monoxime also inhibits the in vivo phosphorylation of DARPP-32 by CDK5 on Thr-75, thereby mimicking one of the effects of dopamine in the striatum. Finally, we show that many, but not all, reported CDK inhibitors are powerful inhibitors of GSK-3 beta. To which extent these GSK-3 beta effects of CDK inhibitors actually contribute to their antimitotic and antitumoral properties remains to be determined. Indirubins constitute the first family of low nanomolar inhibitors of GSK-3 beta to be described.

Mechanisms mediating the effects of IL-3 gene expression on tumor growth

IL-3 gene expression within tumors leads to host-cell infiltration, particularly by macrophages, slower tumor growth, and enhanced immunogenicity. Surprisingly, tumor-associated macrophages (TAMs) from within FSAN-JmIL3 tumors had decreased expression of TNF-alpha and iNOS. On short-term culture, TAMs from FSAN-JmIL3 tumors regained their capacity to produce TNF-alpha and NO, indicating that they were primed in vivo. In vitro experiments were unable to demonstrate differences between FSAN-JmIL3 and FSAN tumor cells in their ability to stimulate TNF-alpha production by TAMs. In the absence of evidence that TAM activation was responsible for the slower growth of FSAN-JmIL3 tumors, the response of tumor cells to these effector molecules was studied. TNF-alpha and NO were cytotoxic for FSAN-JmIL3 cells but growth stimulatory for FSAN. These tumor-related phenotypic changes may contribute as much if not more than functional changes in host infiltrating cells to the slower growth of FSAN-JmIL3 tumors in vivo.

Paullones are potent inhibitors of glycogen synthase kinase-3beta and cyclin-dependent kinase 5/p25

Paullones constitute a new family of benzazepinones with promising antitumoral properties. They were recently described as potent, ATP-competitive, inhibitors of the cell cycle regulating cyclin-dependent kinases (CDKs). We here report that paullones also act as very potent inhibitors of glycogen synthase kinase-3beta (GSK-3beta) (IC50: 4-80 nM) and the neuronal CDK5/p25 (IC50: 20-200 nM). These two enzymes are responsible for most of the hyperphosphorylation of the microtubule-binding protein tau, a feature observed in the brains of patients with Alzheimer's disease and other neurodegenerative 'taupathies'. Alsterpaullone, the most active paullone, was demonstrated to act by competing with ATP for binding to GSK-3beta. Alsterpaullone inhibits the phosphorylation of tau in vivo at sites which are typically phosphorylated by GSK-3beta in Alzheimer's disease. Alsterpaullone also inhibits the CDK5/p25-dependent phosphorylation of DARPP-32 in mouse striatum slices in vitro. This dual specificity of paullones may turn these compounds into very useful tools for the study and possibly treatment of neurodegenerative and proliferative disorders.

Cardiac troponin I: a marker for post-burn cardiac injury

Cardiac troponin I (cTnI) was measured by chemiluminescent immunoassay following burn injury. Thirty patients [total body surface area (TBSA) of burn 15-98%] were included in this study and each had four to six blood samples collected at 2-day intervals between the 5th and 14th days post-burn. All patients were found to have increased cTnI on two or more occasions. The mean cTnI concentration was significantly higher in patients with TBSA of burn > 30% (0.34 microg/L compared with 0.09 microg/L, P<0.001) and in those with obvious burn wound exudation (0.32 microg/L compared with 0.12 microg/L, P<0.01). cTnI concentrations peaked at the time when there was obvious burn wound exudation or spontaneous separation of eschar, then decreased after surgical excision. Two patients with persistently high cTnI concentrations developed tachycardia. We conclude that burned patients have varying degrees of non-ischaemic cardiac injury, manifesting as leakage of cTnI from myocytes into the circulation.

Are hybrid fibers a common motif of canine laryngeal muscles? Single-fiber analyses of myosin heavy-chain isoform composition

BACKGROUND

The canine lateral cricoarytenoid muscle contains a large proportion of muscle fibers that coexpress various combinations of myosin heavy-chain isoforms (ie, so-called hybrid fibers).

OBJECTIVE

To test the hypothesis that hybrid fibers are a common motif throughout laryngeal muscles.

DESIGN

The posterior cricoarytenoid, canine cricothyroid, and thyroarytenoid muscles were removed from 5 beagle dogs. The posterior cricoarytenoid and canine cricothyroid muscles were each dissected into horizontal, oblique, and rectus regions. The thyroarytenoid was separated into medial and lateral regions. Approximately 40 single fibers were microdissected from each region ( approximately 1800 total fibers were sampled) and placed into a denaturing sample buffer. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was then used to separate the individual myosin heavy-chain isoforms.

RESULTS

Each laryngeal muscle contained hybrid fibers; however, the types and proportions of hybrid fibers were clearly muscle specific. Within a given muscle, there were relatively minor regional differences in the types and proportions of hybrid fibers.

CONCLUSION

If the myosin heavy-chain isoform composition of a single fiber can be used as a "physiological marker," then the extent of hybridism may reveal the diversity of activity required of a given laryngeal muscle.

New perspectives about human laryngeal muscle: single-fiber analyses and interspecies comparisons

BACKGROUND

In companion studies on canine and rodent laryngeal muscle, we observed that (1) muscle fibers in both the canine and rodent posterior cricoarytenoid (PCA) muscles have a slower myosin heavy-chain (MyHC) isoform profile than those in the thyroarytenoid (TA) muscle; (2) the muscle fiber composition of PCA and TA muscles in canines and rodents is complex given the presence of so-called hybrid fibers (fibers coexpressing various combinations of MyHC isoforms); (3) the types and proportions of hybrid fibers are both muscle specific and, in some cases, region specific; and (4) the MyHC isoform profile of canine laryngeal muscle appears to be slower than that of rodent laryngeal muscle, suggesting the possibility that larger mammals have a slower MyHC isoform profile.

OBJECTIVES

Given the findings of these companion studies and the fact that very little is known about the MyHC isoform composition of laryngeal muscle fibers, the primary objectives of this study were to determine (1) the types of MyHC isoforms found in the human PCA and TA muscles, (2) if there were regional differences in MyHC isoform composition, (3) if hybrid fibers commonly occur in human laryngeal muscle, and (4) if the MyHC isoform profile of human laryngeal muscle is slower than that of canine and rodent laryngeal muscle.

RESULTS AND CONCLUSIONS

The findings of this study clearly demonstrate that both the PCA and TA muscles in humans express 3 types of MyHC isoforms (ie, slow type I, fast type IIA, and fast type IIX MyHC isoforms). At the single-fiber level, there were distinct regional differences and hybrid fibers were a common occurrence. Finally, the data demonstrate that the PCA and TA muscles of humans have a slower MyHC profile than that found in either canine or rodent laryngeal muscle.

Single-fiber myosin heavy-chain isoform composition of rodent laryngeal muscle: modulation by thyroid hormone

BACKGROUND

Studies have shown that canine laryngeal muscle contains a large number of muscle fibers that coexpress varying combinations of myosin heavy-chain (MyHC) isoforms. Currently, it is not clear whether this phenomenon is unique to canine laryngeal muscle or occurs in all mammals.

OBJECTIVES

To examine the single-fiber MyHC isoform composition of rodent laryngeal muscle and to examine the plasticity of single-fiber MyHC isoform composition via manipulation of thyroid state.

RESULTS

(1) Findings of single-fiber electrophoretic analyses clearly demonstrate that most fibers in both the posterior cricoarytenoid and thyroarytenoid muscles exhibit MyHC polymorphism. However, the proportions and patterns of polymorphism appear to be muscle specific. (2) Although the fast type IIL isoform was observed in fibers from both muscles, it was always coexpressed in combination with other MyHC isoforms (ie, no pure type IIL fibers were found), and always represented a minor proportion of the total MyHC pool. (3) Altering the thyroid state proved a useful tool for exploring the scope of MyHC isoform expression in these muscles. While the posterior cricoarytenoid muscle seemed more sensitive to the thyroid state, transitions in both muscles were primarily confined to the fast type IIX and IIB MyHC isoforms.

CONCLUSION

The findings of this study support the concept that single-fiber MyHC polymorphism occurs commonly in mammalian laryngeal muscle.

Inhibition of cyclin-dependent kinases, GSK-3beta and CK1 by hymenialdisine, a marine sponge constituent

BACKGROUND

Over 2000 protein kinases regulate cellular functions. Screening for inhibitors of some of these kinases has already yielded some potent and selective compounds with promising potential for the treatment of human diseases.

RESULTS

The marine sponge constituent hymenialdisine is a potent inhibitor of cyclin-dependent kinases, glycogen synthase kinase-3beta and casein kinase 1. Hymenialdisine competes with ATP for binding to these kinases. A CDK2-hymenialdisine complex crystal structure shows that three hydrogen bonds link hymenialdisine to the Glu81 and Leu83 residues of CDK2, as observed with other inhibitors. Hymenialdisine inhibits CDK5/p35 in vivo as demonstrated by the lack of phosphorylation/down-regulation of Pak1 kinase in E18 rat cortical neurons, and also inhibits GSK-3 in vivo as shown by the inhibition of MAP-1B phosphorylation. Hymenialdisine also blocks the in vivo phosphorylation of the microtubule-binding protein tau at sites that are hyperphosphorylated by GSK-3 and CDK5/p35 in Alzheimer's disease (cross-reacting with Alzheimer's-specific AT100 antibodies).

CONCLUSIONS

The natural product hymenialdisine is a new kinase inhibitor with promising potential applications for treating neurodegenerative disorders.

Localization of a T-cell epitope of superantigen toxic shock syndrome toxin 1 to residues 125 to 158

Toxic shock syndrome toxin 1 (TSST-1) is a member of the staphylococcal enterotoxin superantigen family. So far, little is known about T-cell epitopes on superantigens. In this study, we developed an improved method for localizing T-cell epitopes on superantigens that involved synthetic peptides plus costimulation by CD28 or phorbol myristate acetate. Using this method, we localized a T-cell epitope to a 34-residue region, TSST-1 (residues 125 to 158), which possessed only two of four TSST-1-targeted beta-chain variable element (Vbeta) specificities of T-cell receptors in humans and mice, human Vbeta2 and murine Vbeta15.

A new concept in laryngeal muscle: multiple myosin isoform types in single muscle fibers of the lateral cricoarytenoid

This report describes the first known investigation of canine laryngeal muscle in which single fibers were dissected and their myosin heavy chain (MHC) isoform content was analyzed. Both SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot techniques were used. The data from single fiber SDS-PAGE indicate that the lateral cricoarytenoid (LCA) is predominantly a fast muscle composed of the following MHC isoforms: Type I, 16.3%; Type IIA, 71.3%; Type IIX, 10.4%; and Type IIB, 2.0%. The results reveal a phenomenon that, to our knowledge, has not been previously described for laryngeal muscle: the presence of two or more MHC isoforms in a single canine LCA muscle fiber. A large number (41%) of muscle fibers coexpressed two or more MHC isoforms. The three most common patterns of coexpression were Type IIA/IIX (72%), Type IIA/I (16%), and Type IIA/IIX/I (8%). Interestingly, the fast Type IIX MHC isoform was typically present with other isoforms and rarely found by itself in individual fibers. Additional experiments are underway to determine whether other laryngeal muscles exhibit such an unusually high ratio of MHC isoform polymorphism.