Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

[Prevalence of frailty and related factors in middle-aged and elderly people in island and mountainous areas of Taizhou, Zhejiang Province]

Objective: To compare the prevalence of frailty and related factors in middle-aged and elderly people aged ≥45 years in island and mountainous areas of Taizhou, Zhejiang Province. Methods: Based on cross-sectional design, stratified cluster sampling and quota sampling methods were adopted. One administrative district was randomly selected from each of six coastal and three inland administrative districts in Taizhou during July to August, representing two different geographical terrains. In the island area (Jiaojiang District), all residents aged ≥45 years were included by cluster sampling. In the mountainous area (Xianju County), participants were selected through quota sampling, with same gender and age distributions. Data about their demographic characteristics, lifestyle and health-related factors were collected through questionnaire surveys and laboratory examinations. The prevalence of frailty was assessed using the Fried frailty phenotype scale. Hierarchical analysis and multivariate logistic regression analysis were used to compare the influencing factors of frailty. Results: A total of 1 011 local residents were studied, in whom island and mountainous residents accounted for 48.1% (486/1 011) and 51.9% (525/1 011) respectively; men and women accounted for 45.9% (464/1 011) and 54.1% (547/1 011) respectively. Middle-aged (45-49 years), younger elderly (60-74 years), and older elderly (≥75 years) residents accounted for 38.6% (390/1 011), 44.6% (451/1 011), and 16.8% (170/1 011) respectively. The overall prevalence rate of frailty was 3.6% (36/1 011), the prevalence rate was 3.7% (17/464) in men and 3.5% (19/547) in women. The prevalence rates in age groups 45-59,60-74 years and ≥75 years were 0.3% (1/390), 2.2% (10/451), and 14.7% (25/170), respectively. The prevalence rates of frailty and pre-frailty in island area were 6.0% (29/486) and 39.1% (190/486), respectively, which was higher than those in mountainous area (1.3%, 7/525) and (30.9%, 162/525). After adjusting for potential confounding factors, the risk for frailty in island residents was significantly higher than that in mountainous residents (aOR=1.55,95%CI: 1.07-2.25,P=0.019). In island area, older age (60-74 years:aOR=2.52,95%CI: 1.56-4.13; ≥75 years:aOR=11.65,95%CI:5.38-26.70), being women (aOR=1.94,95%CI: 1.20-3.17), suffering from depression (aOR=1.09,95%CI:1.02-1.17) were associated with frailty symptoms. In mountainous area, older age was also associated with an increased risk of frailty symptoms, but the OR value was lower than those in island area (60-74 years: aOR=1.74,95%CI:1.04-2.94;≥75 years: aOR=4.78,95%CI:2.45-9.50). Polydrug use (aOR=2.08,95%CI: 1.14-3.80) and suffering from depression (aOR=1.10,95%CI: 1.02-1.18) had significant positive association with frailty symptoms. Higher education level had significant negative association with frailty symptoms (junior high school: aOR=0.40,95%CI: 0.21-0.75; senior high school and technical secondary school: aOR=0.29,95%CI: 0.15-0.53; college or above:aOR=0.22,95%CI: 0.11-0.42). Conclusions: The prevalence of frailty in middle-aged and elderly community residents was significantly higher in island area than in mountainous area in Taizhou. The frailty-related factors varied with area. The elderly people (≥75 years) and women in island area had higher risk for frailty. Older age and suffering from depression were the independent risk factors for frailty. It is necessary to pay attention to the health risk factors and special environment in island area, and take comprehensive intervention measures to delay the process of debilitation and improve the quality of life of middle-aged and elderly people.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

First Detection of Photons with Energy beyond 100 TeV from an Astrophysical Source

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100  TeV. As a result, we observed 24 photonlike events with E>100  TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100  TeV from an astrophysical source.

IGFBP2 promotes vasculogenic mimicry formation via regulating CD144 and MMP2 expression in glioma

Vasculogenic mimicry (VM) refers to the fluid-conducting channels formed by aggressive tumor cells rather than endothelial cells (EC) with elevated expression of genes associated with vascularization. VM has been considered as one of the reasons that glioblastoma becomes resistant to anti-VEGF therapy. However, the molecular basis underlying VM formation remains unclear. Here we report that the insulin-like growth factor-binding protein 2 (IGFBP2) acts as a potent factor to enhance VM formation in glioma. Evidence showed that elevated IGFBP2 expression was positively related with VM formation in patients with glioma. Enforced expression of IGFBP2 increased network formation of glioma cells in vitro by activating CD144 and MMP2 (Matrix Metalloproteinase 2). U251 cells with stable knockdown of IGFBP2 led to decreased VM formation and tumor progression in orthotopic mouse model. Mechanistically, IGFBP2 interacts with integrin α5 and β1 subunits and augments CD144 expression in a FAK/ERK pathway-dependent manner. Luciferase reporter and ChIP assay suggested that IGFBP2 activated the transcription factor SP1, which could bind to CD144 promoter. Thus, IGFBP2 acts as a stimulator of VM formation in glioma cells via enhancing CD144 and MMP2 expression.

[Clinical observation of postprandial hypotension in patients with hypertensive and coronary heart disease]

Objective: To explore the prevalence and clinical characteristics of postprandial hypotension(PPH) in patients with essential hypertension and coronary heart disease. Methods: A total of 197 patients with essential hypertension and coronary heart disease, who had been treated in the First Department of Cardiology of the Second Hospital of Hebei Medical University from December, 2013 to December, 2014 were included. The patients' blood pressure before breakfast, lunch and dinner and 30, 60, 90, 120 minutes after the meal were monitored. Subjects were classified into PPH group (n=37) and non-PPH group (NPPH, n=160) according to postprandial decrease in systolic blood pressure, to explore the clinical characteristics and related factors and the major adverse cardiac and cerebral vascular events of PPH. Results: Among 197 patients, 37 cases (18.8%) showed at least once postprandial decline in systolic blood pressure greater than and equal to 20 mmHg. The incidence of PPH after breakfast and dinner were higher than lunch (P<0.05). There was no significant difference in the incidence of PPH among different age groups, among patients accompanied with different diseases, and among patients with different dining position (all P>0.05). According to the baseline systolic blood pressure, patients can be divided into 4 groups(<120 mmHg, 120-129 mmHg, 130-139 mmHg, >140 mmHg), the higher the level of the baseline systolic blood pressure was, the higher the incidence of PPH was. And the incidence of major adverse cardiac and cerebral vascular events in patients during hospitalization were increased by PPH. Conclusions: The prevalence of PPH in the patients with essential hypertension and coronary heart disease is 18.8%. The incidence of PPH after breakfast and dinner is higher than lunch. The baseline systolic blood pressure is considered to be the risk factor of PPH. And PPH could lead to an increase of the incidence of major adverse cardiac and cerebral vascular events.

Analysis of metabolic profiles of generalized aggressive periodontitis

BACKGROUND AND OBJECTIVE

The specific pathogenesis of generalized aggressive periodontitis (GAgP) has not yet been clarified, and few studies have focused on the association between GAgP and metabolomics. To elucidate the roles of metabolic profiles in the status of GAgP, this study aimed to identify the differential metabolic profiles between patients with GAgP and healthy controls using an untargeted metabolomic profiling method.

MATERIAL AND METHODS

Serum and gingival crevicular fluid samples were collected from healthy controls (n = 20) and patients with GAgP (n = 20) in this cross-sectional study. The relative levels of biomarkers in the samples were measured by gas chromatography-mass spectrometry. Principal components analysis and orthogonal partial least-squares discriminant analysis were used for statistical analysis. Metabolites were analysed qualitatively using the FiehnLib and NIST databases. Full-mouth probing depth and clinical attachment loss were recorded as indexes of periodontal disease.

RESULTS

A total of 349 metabolites were qualitatively detected in the gingival crevicular fluid samples, and 200 metabolites were detected in the serum samples. Compared with healthy controls, patients with GAgP showed significant increases in serum urea and allo-inositol levels. In contrast, glutathione, 2,5-dihydroxybenzaldehyde, adipic acid and 2-deoxyguanosine levels were decreased in patients with GAgP. In the gingival crevicular fluid samples, noradrenaline, uridine, α-tocopherol, dehydroascorbic acid, xanthine, galactose, glucose-1-phosphate and ribulose-5-phosphate levels were increased in patients with GAgP, while thymidine, glutathione and ribose-5-phosphate levels were decreased.

CONCLUSION

The metabolomics analysis by gas chromatography-mass spectrometry is an effective and minimally non-invasive way to differentiate the metabolites characteristic of patients with GAgP. Both serum and gingival crevicular fluid metabolomics are significantly different between patients with GAgP and healthy controls. These metabolic profiles have great potential in detecting GAgP and helping to understand its underlying mechanisms.

Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

Anesthesia for patients with tracheal bronchus

Tracheal bronchus is a congenital anatomical variant of patients with accessory bronchus in the right upper lobe deriving directly from the supracarinal trachea. Pre-operative consultation with the anesthesiologist is important for patient safety and can avoid adverse effects induced by endotracheal intubation. In this report, we described a case of tracheal bronchus in which general anesthesia was performed for video-assisted thoracoscopic surgery. We discussed some of the issues surrounding to complications in tracheal bronchus.

Mitoxantrone, etoposide and cytarabine following epigenetic priming with decitabine in adults with relapsed/refractory acute myeloid leukemia or other high-grade myeloid neoplasms: a phase 1/2 study

DNA methyltransferase inhibitors sensitize leukemia cells to chemotherapeutics. We therefore conducted a phase 1/2 study of mitoxantrone, etoposide, and cytarabine following “priming” with 5-10 days of decitabine (dec/MEC) in 52 adults (median age 55 [range: 19-72] years) with relapsed/refractory acute myeloid leukemia (AML) or other high-grade myeloid neoplasms. During dose escalation in cohorts of 6-12 patients, all dose levels were well-tolerated. As response rates appeared similar with 7 and 10-days of decitabine, a 7-day course was defined as the recommended phase 2 dose (RP2D). Among 46 patients treated at/above the RP2D, 10 (22%) achieved a complete remission (CR), 8 without measurable residual disease; five additional patients achieved CR with incomplete platelet recovery, for an overall response rate of 33%. Seven patients (15%) died within 28 days of treatment initiation. Infection/neutropenic fever, nausea, and mucositis were the most common adverse events. While the CR rate compared favorably to a matched historic control population (observed/expected CR ratio=1.77), CR rate and survival were similar to two contemporary salvage regimens used at our institution (G-CLAC and G-CLAM). Thus, while meeting the pre-specified efficacy goal, we found no evidence that dec/MEC is substantially better than other cytarabine-based regimens currently used for relapsed/refractory AML.

[The role of soft tissue transplantation in the reconstruction of gingival papilla]

Black triangle caused by gingival papilla loss is an ordinary clinical problem. Gingival recession and alveolar bone absorption in the area of gingival papilla lead to the increase of the vertical distance from the adjacent contact point to the alveolar ridge. Periodontal soft tissue grafts play a certain role in the gingival papilla reconstruction. This paper reviewed the effects of soft tissue grafts on the reconstruction of gingival papilla loss through following several aspects, summary of gingival papilla loss, gum soft tissue reconstruction, biological and chemical factors influencing gingival papilla reconstruction. The role of coronally advanced flap surgery, semilunar coronal repositioned flap surgery, subepithelial connective tissue graft, pedicle flap graft, envelop flap graft and tunnel technique were evaluated.

Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners

BACKGROUND

Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture.

METHODS

Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability.

FINDINGS

Heelstrike runners experienced greater impact loading immediately after landing pattern switch (P<0.004). There was an increase in the longitudinal ankle joint contact force when they landed with forefoot (P=0.003). However, there was no significant difference in both peak tibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986).

INTERPRETATION

Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown.

Nanopatterned graphene on a polymer substrate by a direct peel-off technique

A graphene (Gr) on a polyimide (PI) polymer film (Gr-PI film), obtained by a direct peel-off technique, is proposed and investigated. Thanks to its high transparency, electrical conductivity, mechanical strength, and chemical durability, the Gr-PI film is an ideal substrate for flexible electronic and optoelectronic devices, including transistors, light-emitting diodes, and plasmonic antennas. It is obtained using a straightforward method. After spin coating and curing a PI film on Gr previously grown on Cu, one can separate the Gr-PI film from the Cu foil thanks to the difference in the adhesive energy between the Gr-Cu and Gr-PI interfaces. The resulting Gr-PI film shows an average electrical sheet resistance ranging from 520 to 860 Ω/sq and a very high optical transmission (>90%), which have allowed the demonstration of a transparent heater. The surface morphology of the Gr-PI film follows that of the Cu foil, with the latter maintaining its surface properties and allowing in this way its reuse in subsequent chemical vapor deposition growth. The method can also be applied to patterned Gr, as is demonstrated for nanosize ribbons with a width of a few tens of nanometers.

Molecular modelling, synthesis, cytotoxicity and anti-tumour mechanisms of 2-aryl-6-substituted quinazolinones as dual-targeted anti-cancer agents

BACKGROUND AND PURPOSE

Our previous study demonstrated that 6-(pyrrolidin-1-yl)-2-(3-methoxyphenyl)quinazolin-4-one (HMJ38) was a potent anti-tubulin agent. Here, HMJ38 was used as a lead compound to develop more potent anti-cancer agents and to examine the anti-cancer mechanisms.

EXPERIMENTAL APPROACH

Using computer-aided drug design, 2-aryl-6-substituted quinazolinones (MJ compounds) were designed and synthesized by introducing substituents at C-2 and C-6 positions of HMJ38. The cytotoxicity of MJ compounds towards human cancer cells was examined by Trypan blue exclusion assay. Microtubule distribution was visualized using TubulinTracker(TM) Green reagent. Protein expression of cell cycle regulators and JNK was assessed by Western blot analysis.

KEY RESULTS

Compounds MJ65-70 exhibited strong anti-proliferative effects towards melanoma M21, lung squamous carcinoma CH27, lung non-small carcinoma H460, hepatoma Hep3B and oral cancer HSC-3 cells, with one compund MJ66 (6-(pyrrolidin-1-yl)-2-(naphthalen-1-yl)quinazolin-4-one) highly active against M21 cells (IC50 about 0.033 μM). Treatment of CH27 or HSC-3 cells with MJ65-70 resulted in significant mitotic arrest accompanied by increasing multiple asters of microtubules. JNK protein expression was involved in the MJ65-70-induced CH27 and M21 cell death. Consistent with the cell cycle arrest at G2/M phase, marked increases in cyclin B1 and Bcl-2 phosphorylation were also observed, after treatment with MJ65-70.

CONCLUSIONS AND IMPLICATION

MJ65-70 are dual-targeted, tubulin- and JNK-binding, anti-cancer agents and induce cancer cell death through up-regulation of JNK and interfering in the dynamics of tubulin. Our work provides a new strategy and mechanism for developing dual-targeted anti-cancer drugs, contributing to clinical anti-cancer drug discovery and application.

Outcomes after surgery in patients with previous stroke

BACKGROUND

Limited information is available on the association between a medical history of stroke and postoperative outcomes. This study investigated the outcomes following non-neurological surgery in patients with previous stroke.

METHODS

Using Taiwan's National Health Insurance Research Database, a nationwide cohort study was conducted of patients who underwent non-neurological surgery between 2008 and 2010 with a medical history of stroke in the 24-month period before operation. Patients who had non-neurological surgeries without previous stroke were selected as controls by the propensity score-matched pair method. Thirty-day postoperative complications and in-hospital mortality were compared between the two groups.

RESULTS

Some 1 426 795 adults underwent major inpatient non-neurological surgery, of whom 45 420 had a medical history of previous stroke. Patients with previous stroke who underwent surgery had an increased risk of postoperative pneumonia, septicaemia, acute renal failure, acute myocardial infarction, pulmonary embolism and 30-day in-hospital mortality (adjusted rate ratio (RR) 1·79, 95 per cent c.i. 1·61 to 1·99). Compared with controls, patients with previous stroke due to intracerebral haemorrhage (RR 3·41, 2·97 to 3·91), and those who were treated in intensive care (RR 2·55, 2·24 to 2·90) or underwent neurosurgery (RR 2·49, 2·12 to 2·92), had an increased 30-day in-hospital mortality rate. Postoperative mortality also increased with stroke-related co-morbidities, and with stroke 1-6 months before surgery (RR 3·31, 2·91 to 3·75).

CONCLUSION

Patients with previous stroke had a higher risk of adverse postoperative outcomes; their 30-day in-hospital mortality rate was nearly twice that of patients without previous stroke.

Postoperative adverse outcomes after non-hepatic surgery in patients with liver cirrhosis

BACKGROUND

Postoperative adverse outcomes in patients with liver cirrhosis are not completely understood. This study evaluated the association between liver cirrhosis and adverse outcomes after non-hepatic surgery.

METHODS

Reimbursement claims were used to identify patients with preoperative liver cirrhosis who underwent non-hepatic surgery from 2004 to 2007. Control patients without cirrhosis were matched by age, sex, type of surgery and anaesthesia. The adjusted odds ratios (ORs) and 95 per cent confidence intervals (c.i.) of postoperative adverse events associated with liver cirrhosis were analysed by multivariable logistic regression.

RESULTS

Thirty-day mortality rates among 24 282 patients with cirrhosis and 97 128 control patients were 1·2 per cent (299 deaths) and 0·7 per cent (635 deaths) respectively. Liver cirrhosis was associated with postoperative 30-day mortality (OR 1·88, 95 per cent c.i. 1·63 to 2·16), acute renal failure (OR 1·52, 1·34 to 1·74), septicaemia (OR 1·42, 1·33 to 1·51) and intensive care unit admission (OR 1·39, 1·33 to 1·45). Postoperative mortality increased in patients who had liver cirrhosis with viral hepatitis (OR 2·87, 1·55 to 5·30), alcohol dependence syndrome (OR 3·74, 2·64 to 5·31), jaundice (OR 5·47, 3·77 to 7·93), ascites (OR 5·85, 4·62 to 7·41), gastrointestinal haemorrhage (OR 3·01, 2·33 to 3·90) and hepatic coma (OR 5·11, 3·79 to 6·87).

CONCLUSION

Patients with liver cirrhosis had increased mortality and complications after non-hepatic surgery, particularly those with cirrhosis-related clinical indicators.

Probe of the solar magnetic field using the "cosmic-ray shadow" of the sun

We report on a clear solar-cycle variation of the Sun’s shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun’s shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun’s shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun’s shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun’s shadow observed in the TeV cosmic-ray flux.

Adverse postoperative outcomes in surgical patients with immune thrombocytopenia

Background

Patients with immune thrombocytopenia (ITP) are likely to have various medical co-morbidities, yet their global features regarding adverse postoperative outcomes and use of medical resources when undergoing major surgery are unknown. The objective of this study was to validate whether ITP is an independent risk factor for adverse postoperative outcomes, and to explore the potential clinical predictors of outcomes after major surgery among patients with ITP.

Methods

A retrospective population-based cohort study was conducted using Taiwan's National Health Insurance Research Database, controlling for preoperative co-morbidities by means of multiple logistic regression. Major postoperative complication and mortality rates, and in-hospital medical costs were analysed.

Results

The study included 11 085 surgical patients with ITP and 44 340 controls without ITP matched for sex, age, and type of surgery and anaesthesia. Surgical patients with ITP had a higher risk of postoperative death (odds ratio (OR) 1·89, 95 per cent confidence interval 1·57 to 2·27), and overall postoperative complications (OR 1·47, 1·39 to 1·56), and increased hospital stay (OR 1·90, 1·80 to 2·01), admission to the intensive care unit (OR 1·73, 1·63 to 1·83) and medical costs (OR 1·89, 1·79 to 1·99). Amount of preoperative platelet and/or red blood cell transfusion, emergency visits and admission to hospital for ITP care were identified as risk factors for adverse postoperative outcomes.

Conclusion

Patients with ITP undergoing surgery are at increased risk of adverse perioperative events, particularly if blood or blood product transfusion are required preoperatively, or the procedure is done as an emergency.

Graphene as an anti-permeation and protective layer for indium-free transparent electrodes

We show that graphene can be used as a protective layer for transparent electrodes made of materials which would otherwise deteriorate when exposed to the environment. In particular, we investigate aluminum-doped zinc oxides and ultrathin copper films capped with a one-atom graphene layer in damp heat (95% relative humidity and 95 °C) and high temperature (up to 180 °C) conditions. The results clearly indicate that a graphene layer can strongly reduce degradation of the electrodes' electrical, optical properties and surface morphology, thus preserving the functionality of the transparent electrodes. The proposed technique is particularly suitable for flexible optoelectronic devices thanks to the mechanical strength of graphene when subjected to bending.

Two Strategies to Intensify Evidence-based Medicine Education of Undergraduate Students: A Randomised Controlled Trial

Introduction: Undergraduate evidence-based practice (EBP) is usually taught through standalone courses and workshops away from clinical practice. This study compared the effects of 2 clinically integrated educational strategies on final year medical students. Materials and Methods: Final year medical students rotating to the general medicine service for a 2-week internship were randomly assigned to participate in a weekly EBP-structured case conference focusing on students’ primary care patients (Group A, n = 47), or to receive a weekly didactic lecture about EBP (Group B, n = 47). The teaching effects of these 2 interventions were evaluated by a validated instrument for assessment of EBP related knowledge (EBP-K), attitude (EBP-A), personal application (EBP-P), and anticipated future use (EBP-F) on the first and last days of rotation. Results: All scores improved significantly after the 2-week EBM-teaching for both groups. When compared to Group B, students in Group A had significantly higher post-intervention scores of EBP-K (21.2 ± 3.5 vs 19.0 ± 4.6; ie. 57.8 ± 72.9% vs 29.1 ± 39.1%; P <0.01) and EBP-P (18.7 ± 4.3 vs 15.3 ± 3.9; ie. 28.5 ± 25.5 % vs 14.1 ± 18.7 %; P <0.001). In contrast, the scores of EBP-A and EBP-F were similar between the 2 groups. Conclusion: Structured case conference, when compared to the didactic lectures, significantly improved EBP-K and EBP-P for final year medical students. Key words: Evidence-based medicine, Medical education, Preclinical medical student

Two strategies to intensify evidence-based medicine education of undergraduate students: a randomised controlled trial

INTRODUCTION

Undergraduate evidence-based practice (EBP) is usually taught through standalone courses and workshops away from clinical practice. This study compared the effects of 2 clinically integrated educational strategies on final year medical students.

MATERIALS AND METHODS

Final year medical students rotating to the general medicine service for a 2-week internship were randomly assigned to participate in a weekly EBP-structured case conference focusing on students' primary care patients (Group A, n = 47), or to receive a weekly didactic lecture about EBP (Group B, n = 47). The teaching effects of these 2 interventions were evaluated by a validated instrument for assessment of EBP related knowledge (EBP-K), attitude (EBP-A), personal application (EBP-P), and anticipated future use (EBP-F) on the first and last days of rotation.

RESULTS

All scores improved significantly after the 2-week EBM-teaching for both groups. When compared to Group B, students in Group A had significantly higher post-intervention scores of EBP-K (21.2 ± 3.5 vs 19.0 ± 4.6; ie. 57.8 ± 72.9% vs 29.1 ± 39.1%; P <0.01) and EBP-P (18.7 ± 4.3 vs 15.3 ± 3.9; ie. 28.5 ± 25.5 % vs 14.1 ± 18.7 %; P <0.001). In contrast, the scores of EBP-A and EBP-F were similar between the 2 groups.

CONCLUSION

Structured case conference, when compared to the didactic lectures, significantly improved EBP-K and EBP-P for final year medical students.

Clinical characteristics and predictors of mortality in patients with Enterobacter aerogenes bacteremia

BACKGROUND AND PURPOSE

Enterobacter aerogenes is increasingly encountered in nosocomial infections. This study aimed to clarify the clinical characteristics and to identify the predictors of mortality in patients with E. aerogenes bacteremia.

METHODS

From March 2001 to April 2007, all patients with positive blood cultures for E. aerogenes at Taipei Veterans General Hospital, Taipei, Taiwan, were enrolled in this retrospective study. The medical records were reviewed for clinical and laboratory data.

RESULTS

Eighty eight patients were included, 9 (10.2%) of whom died of E. aerogenes bacteremia. Most of the patients had comorbidities. Seventy nine patients (89.8%) had nosocomial infections, and 43 patients (48.9%) had polymicrobial infections. Eighty four patients (95.5%) presented with fever. Empirical antimicrobial therapy was administered for 80 patients (90.9%), but was appropriate for only 55 patients (62.5%). Of the 9 patients who died, 8 had polymicrobial infection, 5 of whom had nosocomial pneumonia, and 6 did not receive appropriate antimicrobial therapy. Multivariate analysis indicated that high Acute Physiology and Chronic Health Evaluation (APACHE) II score (>16) [odds ratio (OR), 16.569; 95% confidence interval (CI), 1.24-221.24; p = 0.034] and strains not susceptible to extended-spectrum cephalosporins (OR, 9.21; 95% CI, 1.02-83.04; p = 0.048) were independent risk factors for mortality.

CONCLUSIONS

The severity of E. aerogenes bacteremia, reflected by high APACHE II score and isolation of strains with no susceptibility to extended-spectrum cephalosporins, were independent risk factors for mortality. Patients with severe illness and isolates resistant to extended-spectrum cephalosporins should be treated with more potent antimicrobial agents.

Cyclosporin A pre-incubation attenuates hypoxia/reoxygenation-induced apoptosis in mesenchymal stem cells

Although mesenchymal stem cells (MSCs) are being tested for cardiac repair, the majority of transplanted cells undergo apoptosis in the ischaemic heart because of the effects of ischaemia/reperfusion, poor blood supply and other pro-apoptotic factors. Several experimental and clinical studies have suggested that cyclosporin A (CsA) treatment reduces apoptosis in human endothelial cells and neurocytes. However, the effect of CsA on the apoptosis in MSCs is still unclear. In this study, we investigated whether CsA could inhibit hypoxia/ reoxygenation (H/R)-induced apoptosis in MSCs. MSCs pre-incubated with or without CsA were subjected to 6 h of hypoxia followed by 12 h of reoxygenation. Our data showed that pre-incubation with 0.5-5 microM CsA dose-dependently protected the MSCs from H/R injury, as evidenced by decreased apoptosis and increased cell viability. CsA inhibited the H/R-induced translocation of cytochrome c, increased bcl-2 expression and restored mitochondrial membrane potential. CsA also increased the expression of p-BAD. We propose that preincubation MSCs with CsA inhibits MSC apoptosis through the mitochondrial and BAD pathway.

Polypeptide growth factors in bone matrix

The presence of many types of polypeptide growth factors in the mineralized extracellular matrix of bone is now well established. These factors are generally referred to as bone-derived growth factors (BDGFs), and are similar, or possibly identical, to the following species; platelet-derived growth factor (PDGF); acidic and basic forms of fibroblast growth factor (aFGF, bFGF); transforming growth factor beta (TGF-beta); and insulin-like growth factor 1 (IGF-1). Several osteoinductive factors, such as bone morphogenetic protein (BMP) and osteogenin, a skeletal growth factor (SGF), and osteoblast-derived BDGFs, have also been identified. Complete description of the biological functions of these BDGFs which are relevant to bone will ultimately require specific bioassays involving specific cell types in vitro, as well as in vivo animal implant models. Studies with primary rat osteoblast-like cells exposed either to mixed BDGFs, pure TGF-beta, or heparin-purified PDGF, aFGF, or bFGF from bovine bone have shown a general dose-dependent mitogenic effect. Phenotypic changes which accompany the BDGF-induced wave of proliferation include: decreased osteocalcin secretion and a reduction in 1,25-(OH)2 vitamin D3-stimulated osteocalcin synthesis; reduced alkaline phosphatase specific activity; decreased cyclic AMP responsiveness to parathyroid hormone (PTH); and increased collagen synthesis. Bone exhibits the most complex spectrum of growth factor activities of any tissue yet described. In bovine bone powder free of blood and cartilage contamination, the volume concentration of mitogens is up to 20 times greater than that in serum. Bone cells and other indigenous cell types must be considered as possible sources of the BDGFs, in addition to sequestration from blood. Mechanisms for the unmasking or release of BDGFs from the mineralized matrix that result in local action on osteoblasts, endothelial cells, and other target cells are undoubtedly important for the development and maintenance of bone tissue.

Daytime behavioural patterns of slow-growing chickens in deep-litter pens with perches

1. Behavioural patterns of 4 slow-growing local breeds of chickens in Taiwan and China, Taiwan Country chickens, Beijing Fatty chickens, pure Silkies, and upgraded commercial Silkies, were studied from 5 to 16 weeks of age as a reference of management for commercial production. 2. Fifteen males and 15 females of the same breed were housed in a pen. Every breed had 6 pens and 24 pens were studied. 3. Taiwan Country chickens displayed more aggressive, sexual and feather pecking behaviours, had less resting time, the fastest feeding rate and used perches more often. The fast-growing and heavy commercial Silkies had more feeding activity and less preening activity. They were also similar to the crested and docile Beijing Fatty chickens and had less stand/walking and more resting time. The pure Silky bantams showed much more foraging activity than the other breeds. 4. When males started to display more aggression and sexual behaviour, after 8-12 weeks of age, resting time for all birds started to decline and stand/walking increased. 5. These results could imply that different local breeds need different housing systems for the bird's welfare.

Non-typhoidal Salmonella bacteremia in adults

BACKGROUND AND PURPOSE

Very few studies have examined prognostic factors in adult patients with non-typhoidal Salmonella (NTS) bacteremia. The purpose of this study was to identify the prognostic factors of these patients.

METHODS

A total of 79 episodes of NTS bacteremia were identified in 73 patients between January 2001 and December 2003. Susceptibilities to various antimicrobials were determined using disk-diffusion tests and National Committee for Clinical Laboratory Standards criteria. Multiple logistic regression was used to evaluate the relationship between patients' characteristics and covariates of mortality.

RESULTS

There were only 5 episodes (6%) of gastroenteritis, two of which were due to Salmonella septicemia contracted abroad. Potentially predisposing factors were identifiable in 51 episodes (65%). Infections in 24 patients (30%) were due to serogroup B Salmonella and in 22 patients (28%), to serogroup C Salmonella. A logistic regression analysis selected two variables as independently influencing prognosis: coma (p=0.006) and septic shock (p=0.002).

CONCLUSIONS

Thus, most adult patients with NTS bacteremia do not develop gastroenteritis. Patients in shock or coma have poor prognosis, and susceptibility to third-generation cephalosporins, cefepime, and carbapenem is high.

Clinical characteristics and risk factors for attributable mortality in Enterobacter cloacae bacteremia

BACKGROUND AND PURPOSE

Enterobacter spp. have emerged as an important cause of nosocomial bacteremia. The purpose of this study was to delineate the clinical, laboratory and microbiologic features that may influence prognosis of Enterobacter cloacae and enable a stratification of those patients at high risk of mortality.

METHODS

This retrospective study reviewed 108 episodes of E. cloacae bacteremia occurring over a 2-year period (November 2001 to October 2003) at Taipei Veterans General Hospital. Univariate analysis were performed to demonstrate the relation of possible risk factors to death attributable to E. cloacae bacteremia.

RESULTS

Ninety-three episodes (86.1%) were hospital-acquired. The most common portal of entry was the genitourinary tract (17.9%) followed by the gastrointestinal tract (15.1%). Underlying diseases associated with E. cloacae bacteremia were neoplastic diseases (42 episodes, 38.9%), diabetes mellitus (20 episodes, 18.5%) and chronic renal failure (18 episodes, 16.7%). The overall mortality rate was 42.6%, and E. cloacae bacteremia-attributable mortality occurred in 22 patients (20.9%). Factors significantly correlated with death attributable to bacteremia were older age, a higher medium number of underlying diseases, hemoglobin <10 g/dL, serum C-reactive protein >10 mg/dL, hypoalbuminemia, disseminated intravascular coagulation, septic shock, respiratory failure, renal failure (creatinine >2 mg/dL) and delayed clinical response after initiation of antibiotic therapy.

CONCLUSIONS

Antibiotic-resistant isolates and appropriate empirical antibiotic use were not independent predictors of mortality in this study. The condition of patients at onset of symptoms and presence of underlying diseases appear to be important predictors mortality from E. cloacae bacteremia.

Predictors of mortality in Acinetobacter baumannii bacteremia

This study retrospectively investigated 149 episodes of Acinetobacter baumannii bacteremia which occurred during a 41-month period from September 1997 to January 2001. Bacteremia was nosocomial in 139 (93%) of the episodes and community-acquired in 10 (7%). Thirty three deaths (22.1%) were attributed to these episodes of A. baumannii bacteremia. The mean age of survivors was younger than that of patients who died of bacteremia (60.4 +/- 19.9 vs 67.1 +/- 17.4) but this result was not significant on univariate analysis (p=0.084). Previous intensive care unit stay was longer among survivors than among patients who died of bacteremia (9.5 vs 18 days, p=0.048). Factors associated with mortality included immunosuppression (p=0.019), shock (p=0.002), recent surgery (p=0.008), invasive procedures such as central venous catheterization (p=0.002), urinary catheterization (p=0.012), placement of a nasogastric tube (p<0.001), pulmonary catheterization (p=0.015), and mechanical ventilation (p=0.035). The number of underlying conditions (p=0.015) and invasive procedures (p<0.001) were positively correlated with mortality. Mortality was significantly associated with lower platelet count (p=0.001) and lower serum albumin concentration (p=0.005). Patients with catheter-related bacteremia had a high survival rate (96.2%), while survival rate was low in patients with infection originating from the respiratory tract (60.8%). Susceptibility testing by agar dilution test indicated that imipenem was the most effective antibiotic, followed by cefepime and ciprofloxacin. The mortality rate was lower in patients who received 1 or more antibiotics to which the isolates were susceptible, but this difference was not significant (p=0.197). On multivariate analysis, factors that independently correlated with mortality were increased age (p=0.003), immunosuppressive status (p=0.001), recent surgery (p=0.002), acute respiratory failure (p=0.004), acute renal failure (p=0.009) and septic shock (p<0.001). These findings highlight the importance of a treatment strategy based on risk stratification among patients with A. baumannii bacteremia.

Human BMP-7/OP-1 induces the growth and differentiation of adipocytes and osteoblasts in bone marrow stromal cell cultures

We studied the effects of BMP-7/OP-1 on growth and differentiation of bone marrow stromal cells. BMS2, a mouse bone marrow stromal cell line capable of differentiating into adipocytes and osteoblasts, were treated in a serum-free medium containing differentiation agents that favor the expression of both lineages. BMP-7/OP-1 stimulated cell proliferation and differentiation concomitantly. These effects were dose- and growth phase-dependent. Cells were more sensitive to the treatment early in the culture (30-40% confluence) with a significant increase in cell proliferation and markers of differentiation at low concentrations. When treated later in the growth phase (90-100% confluence), no significant increase in cell proliferation was seen. The concentration requirement for cells later in the culture to reach an equivalent degree of differentiation was 3-10- fold higher than for cells treated early. In both cases, the effects on adipocyte differentiation were biphasic; low concentrations stimulated adipocyte differentiation which was inhibited at higher concentrations where stimulation of osteoblast markers were observed. We conclude that cell proliferation and cell differentiation into adipocyte/osteoblast can occur simultaneously under BMP-7/OP-1 treatment.

Synthesis of bicyclic pyrane derivatives via tungsten-mediated [3 + 3] cycloaddition of epoxides with tethered alkynes

Propargyltungsten compounds bearing a tethered epoxide were prepared in short steps from readily available materials. In the presence of various Lewis acids, BF(3).Et(2)O catalysts (25 mol %) most effectively promote the [3 + 3] cycloaddition of the epoxide with its tethered propargyltungsten group, delivering bicyclic pyranyltungsten compounds in reasonable yields. This cyclization proceeds highly diastereoselectively with tolerance of various functional groups. The stereochemical outcome indicates that the cycloaddition is initiated by the ring opening of the epoxides via an exo-attack of the propargyltungsten group. The resulting pyranyltungsten organometallics were demetalated to yield various bicyclic pyranyl derivatives using different oxidants. This new method provides a short enantiospecific synthesis of bicyclic oxygen compounds if chiral epoxide is used in the cyclization. A mechanistic model is presented to rationalize the reaction pathway of this [3 + 3] cycloaddition.

Production of Acinetobacter radioresistens lipase with repeated batch culture in presence of nonwoven fabric

Cultivation of Acinetobacter radioresistens on n-hexadecane for lipase production was investigated with repeated batch culture in the presence of a hydrophobic nonwoven fabric. Lipase production followed the growth-associated model, and the repeated batch culture could achieve both high enzyme yield and increased volumetric productivity. The fabric was shown to be able to disperse n-hexadecane, to adsorb the unused hydrocarbon, and to retain bioemulsifiers excreted from the cells; therefore, it enhanced cell growth and, in turn, lipase production. In the repeated batch culture in the absence of the fabric, lipase yield and volumetric productivity were found to be 21 U/mL and 875 U/L. h, respectively. However, if the fabric was equipped in the fermentor, lipase yield and volumetric productivity increased to 30 U/mL and 2500 U/L. h, respectively. The lipase production profile could be further improved by raising the amount of nitrogen source and, as a result, a lipase yield of 54 U/mL and a volumetric productivity of 2250 U/L. h were obtained. In this study we assess the beneficial effects of nonwoven fabric on lipase production.

Identification of a mouse thiamine transporter gene as a direct transcriptional target for p53

p53 tumor suppressor is a transcription factor that functions, in part, through many of its downstream target genes. We have identified a p53-inducible gene by performing mRNA differential display on IW32 murine erythroleukemia cells containing a temperature-sensitive p53 mutant allele, tsp53(Val-135). Sequence analysis of the full-length cDNA revealed its identity as the mouse homologue of the human thiamine transporter 1 (THTR-1). Induction of the mouse THTR-1 (mTHTR-1) mRNA was detectable as early as 1 h at 32.5 degrees C; upon shifting back to 38.5 degrees C, mTHTR-1 transcript was rapidly degraded with a half-life of less than 2 h. Elevation of mTHTR-1 expression was found in DNA damage-induced normal mouse embryonic fibroblast cells, but not in p53(-/-) mouse embryonic fibroblast cells, suggesting that mTHTR-1 induction was p53-dependent. A region within the first intron of the mTHTR-1 gene bound to p53 and conferred the p53-mediated transactivation. Furthermore, increased thiamine transporter activities were found in cells overexpressing mTHTR-1 and under conditions of DNA damage or p53 activation. Our findings indicate that p53 may be involved in maintaining thiamine homeostasis through transactivation of THTR-1.

Disseminated cutaneous infection with Mycobacterium kansasii: genotyping versus phenotyping

Mycobacterium kansasii is a common and virulent pathogen. However, primary cutaneous M kansasii infection has rarely been reported, totaling to only 34 cases since 1965. This low incidence has not been explained, but probably is due to difficulty in culture or phenotyping. We describe the first reported case of cutaneous M kansasii diagnosed by genotyping, which is based on the DNA extracted from the formalin-fixed and paraffin-embedded tissue.

A Phase I clinical and pharmacological evaluation of sodium phenylbutyrate on an 120-h infusion schedule

PURPOSE

Sodium phenylbutyrate (PB) demonstrates potent differentiating capacity in multiple hematopoietic and solid tumor cell lines. We conducted a Phase I and pharmacokinetic study of PB by continuous infusion to characterize the maximum tolerated dose, toxicities, pharmacokinetics, and antitumor effects in patients with refractory solid tumors.

PATIENTS AND METHODS

Patients were treated with a 120-h PB infusion every 21 days. The dose was escalated from 150 to 515 mg/kg/day. Pharmacokinetics were performed during and after the first infusion period using a validated high-performance liquid chromatographic assay and single compartmental pharmacokinetic model for PB and its principal metabolite, phenylacetate.

RESULTS

A total of 24 patients were enrolled on study, with hormone refractory prostate cancer being the predominant tumor type. All patients were evaluable for toxicity and response. A total of 89 cycles were administered. The dose-limiting toxicity (DLT) was neuro-cortical, exemplified by excessive somnolence and confusion and accompanied by clinically significant hypokalemia, hyponatremia, and hyperuricemia. One patient at 515 mg/kg/day and another at 345 mg/kg/day experienced this DLT. Toxicity resolved < or =12 h of discontinuing the infusion. Other toxicities were mild, including fatigue and nausea. The maximum tolerated dose was 410 mg/kg/day for 5 days. Pharmacokinetics demonstrated that plasma clearance of PB increased in a continuous fashion beginning 24 h into the infusion. In individuals whose V(max) for drug elimination was less than their drug-dosing rate, the active metabolite phenylacetate accumulated progressively. Plasma PB concentrations (at 410 mg/kg/day) remained above the targeted therapeutic threshold of 500 micromol/liter required for in vitro activity.

CONCLUSION

The DLT in this Phase I study for infusional PB given for 5 days every 21 days is neuro-cortical in nature. The recommended Phase II dose is 410 mg/kg/day for 120 h.

Induction of cytochromes P450 1A1 and 1B1 by emodin in human lung adenocarcinoma cell line CL5

Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) is an active compound of many laxative herbal drugs. The present study aimed to determine the effects of emodin on cytochrome P450 (P450)-dependent monooxygenases of human lung adenocarcinoma CL5 cells. Treatment of CL5 cells with 100 microM emodin for 24 h induced benzo[a]pyrene hydroxylation, 7-ethoxyresorufin O-deethylation, and 7-ethoxycoumarin O-deethylation activities of S9 fractions. Immunoblot analysis of CL5 S9 proteins revealed that emodin induced proteins immunorelated to P450s 1A1 and 1B1. Northern blot analysis of total cellular RNA showed that emodin induced P450s 1A1 and 1B1 mRNA levels in CL5 cells. These inductive effects on P450 monooxygenase activity, protein, and mRNA were concentration- and time-dependent. Addition of emodin to CL5 cell microM S9 inhibited its 7-ethoxycoumarin O-deethylation activity. Treatment of CL5 cells with 10 microM 3-methylcholanthrene for 24 h induced monooxygenase activity and P450s 1A1 and 1B1 proteins and mRNA levels. Treatment of the lung cells with 100 microM emodin or purpurin (1,2,4-trihydroxyanthraquinone) for 24 h produced greater induction of P450s 1A1 and 1B1 mRNA than did anthraflavic acid (2,6-dihydroxyanthraquinone) or anthraquinone. The emodin treatment induced P450s 1A1 and 1B1 mRNA in human lung carcinoma NCI-H322 and breast cancer MCF-7 cells. Emodin induced P450 1A1, but not 1B1, mRNA in human hepatoma HepG2 cells. The present study demonstrates that emodin is an inducer of P450s 1A1 and 1B1 protein and mRNA in human lung adenocarcinoma CL5 cells. Modulation of P450 by emodin may be an important factor affecting metabolism and toxicity of the hydroxyanthraquinone in humans.

Suppression of choroidal neovascularization by adeno-associated virus vector expressing angiostatin

PURPOSE

To test the efficacy of a recombinant adeno-associated virus (rAAV) vector that expresses mouse angiostatin in suppressing experimental choroidal neovascularization (CNV) in a rat model.

METHODS

An rAAV vector, rAAV-angiostatin, was constructed to deliver the mouse angiostatin gene. rAAV-angiostatin and a control virus, rAAV-lacZ, were delivered in vivo by subretinal injection in Brown Norway rats, and the delivery was confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR). For a CNV suppression experiment, CNV was generated by fundus krypton laser photocoagulation 7 days after the viral vector injection and was evaluated by fluorescein angiography (FA) and histology. Apoptosis in retina was analyzed using the TUNEL assay. Inflammation in the retina was investigated by immunohistochemistry, using antibodies that recognize lymphocytes.

RESULTS

rAAV-angiostatin injection led to sustained expression of the angiostatin gene in chorioretinal tissue for up to150 days. FA analysis revealed significant reduction of the average sizes of CNV lesions in rAAV-angiostatin-injected eyes when compared with rAAV-lacZ-injected eyes at both 14 (P = 0.019) and 150 (P = 0.010) days after injection. Moreover, histologic analysis of CNV lesions also revealed significantly smaller lesions in rAAV-angiostatin-injected eyes (P = 0.004). As for adverse effects, rAAV-angiostatin injection did not cause inflammation or apoptosis of cells in retina and choroid.

CONCLUSIONS

This is the first report that subretinal injection of rAAV-angiostatin can significantly reduce the sizes of CNV lesions. This and the absence of apoptosis and inflammation in chorioretinal tissue indicate the feasibility of a gene therapy approach for treatment of CNV disease.

Effects of propofol on mitochondrial function and intracellular calcium shift in bovine aortic endothelial model

BACKGROUND

Hypotension was commonly encountered in clinical practice during induction of anesthesia with propofol. The purpose of this study is to investigate the effect of propofol on mitochondrial membrane potential and morphology so as to infer its relation with intracellular calcium mobilization in bovine aortic endothelium.

METHODS

In this study, we used the cultured bovine aortic endothelial cells (Gm 7372a) to elucidate the impact of propofol upon the membrane potential and morphology of mitochondria in correlation with its effect on intracellular calcium shift. The intracellular calcium mobilization within the cells preincubated with or without propofol was evaluated using a fluorescent spectrophotometer (confocal microscope) after being treated with Fluo-3. The mobilization of intracellular calcium was demonstrated by the appearance of "hot spots" released from intracellular stores after the addition of an ionophore, ionomycin, to the incubation system. The membrane potential of mitochondria was measured by DiOC6 and the morphology of the mitochondria was evaluated by the treatment of TM Ros and compared with that by the treatment of the uncoupler, FCCP, as control.

RESULTS

The release of calcium "hot spots" from the intracellular stores (e.g. mitochondria) after the addition of ionomycin was visualized to decrease dramatically within the endothelial cells after preincubation with propofol. The membrane potential of mitochondria was significantly inhibited by pretreatment of propofol at 0.01 mM, 37 degrees C for 30 min. Morphologically, the integrity of mitochondria was distorted and fragmented in the presence of propofol as compared with that of control.

CONCLUSIONS

Our data showed that propofol in clinical concentration, 0.01 mM, could inhibit intracellular calcium shift from the intracellular stores and decrease the membrane potential and distort the morphology of mitochondria in bovine aortic endothelial cells. These inhibitions of the function and disfiguration of the morphology of mitochondria signify that the clinical hypotension induced by propofol might be of a potential mechanism.

A rapid and successful treatment for airbag-related traumatic macular hole

A 28-year-old female was diagnosed as having an airbag-related traumatic macular hole in the right eye 9 days subsequent to a traffic accident. Four weeks after the trauma, the patient's visual acuity was deteriorating to 20/600. Following vitrectomy, membrane peeling, use of autologous serum and intraocular gas tamponade, the hole healed within 12 days, more rapidly than the expected interval for the treatment of a traumatic macular hole. The visual acuities at the 3-month and 1-year follow-up examinations were 20/50, much better than the conventional surgical treatment of idiopathic macular hole and comparable to previous reports of the treatment of traumatic macular hole. Vitrectomy procedure has been proved to be effective for the treatment of traumatic macular hole. Vitrectomy combined with membrane peeling, autologous serum and intraocular gas tamponade can heal the traumatic macular hole more rapidly than the conventional treatment with vitrectomy only.

Ocular ischemic syndrome

BACKGROUND

The purpose of this study was to investigate the clinical features and management of ocular ischemic syndrome (OIS) and factors influencing its development.

METHODS

Ten patients (12 eyes) with OIS underwent detailed medical and ocular histories, complete ophthalmic evaluation including fluorescein angiography, internal carotid artery evaluation by duplex ultrasonography, and management. The following outcome measures were considered: visual acuity, anterior segment neovascularization, lens status, retinal and choroidal changes, and carotid artery stenosis or occlusion.

RESULTS

The mean age of the patients was 63 +/- 8 years. Presenting visual symptoms included gradual (82.5%) or sudden (17.5%) onset of vision loss. At initial visit, eyes with OIS had visual acuity less than or equal to counting fingers in 50%, iris neovascularization in 58%, and neovascular glaucoma in 42%. Initially associated systemic diseases in these patients included arterial hypertension (60%), diabetes mellitus (40%), coronary artery disease (20%), previous stroke (30%) and hemodialysis (10%). Complete occlusion or severe occlusion (70-99%) of the internal carotid artery was seen in 75% on the side of OIS. Panretinal photocoagulation did not prevent OIS from progressing but vitreous hemorrhage and rubeosis iris regressed. Carotid endarterectomy had some benefit in stabilizing or improving vision in patients with OIS.

CONCLUSION

OIS has a poor visual prognosis. It is imperative that the clinician be aware of the signs and symptoms of carotid disease in order to facilitate prompt diagnosis and appropriate referral, because OIS may be the presenting sign of serious ischemic cerebrovascular and ischemic heart disease.

Acute angle-closure glaucoma resulting from spontaneous hemorrhagic retinal detachment in age-related macular degeneration: case reports and literature review

PURPOSE

Acute angle-closure glaucoma resulting from massive subretinal hemorrhage is a rare and catastrophic complication in age-related macular degeneration. Anticoagulant usage had been strongly correlated with this complication in previously reported cases.

METHODS

Four patients (4 eyes), 3 men and 1 woman, developed angle-closure glaucoma with diffuse subretinal hemorrhage and total hemorrhagic retinal detachment.

RESULTS

Serial funduscopic examinations and echographic studies in 2 eyes showed that the blood gradually accumulated in the subretinal space. It took more than 10 days for the bleeding to build up to bullous hemorrhagic retinal detachment and secondary glaucoma. Anti-glaucomatous agents were given and sclerotomy was performed in 3 of the 4 patients. Phthisical changes were observed subsequently in these 3 eyes. The eye that received early drainage of blood was an exception, and a small degree of residual acuity was retained. Three of the 4 patients had diabetes mellitus, and hypertension and vascular diseases were also present in the same 3 patients.

CONCLUSIONS

Diabetes mellitus might be a predisposing factor for the impaired hemostasis. Anti-glaucomatous agents were of no effect in the management of intraocular pressure. Sclerotomy and drainage of blood help control intraocular pressure and relieve ocular pain. Poor final visual acuity is inevitable. However, phthisical changes might be prevented with early sclerotomy and drainage of blood.