P5644Hypoglycemic episodes increase the risk of ventricular arrhythmias and sudden cardiac arrest in patients with type 2 diabetes - a nationwide cohort study

Background

Hypoglycemic episode (HE) increases the risk of cardiovascular mortality. The impact of HE on the risk of sudden death remains unclear. We hypothesized that HE increases the risks of ventricular arrhythmia (VA) and sudden cardiac arrest (SCA), and that anti-diabetic agents (ADAs) causing hypoglycemia also increase the risks of VA and SCA.

Methods

Patients aged ≥20 years with newly diagnosed diabetes were identified from the Taiwan National Insurance Database. HE was defined as the presentation of hypoglycemic coma or specified/unspecified hypoglycemia. For control group, we included diabetic patients without HE, and they were frequency-matched to the HE group at a 4:1 ratio. The primary outcome was the occurrence of any event of VA (including ventricular tachycardia and fibrillation) and SCA during the defined follow-up periods. Multivariate Cox hazards regression model was used to evaluate the hazard ratio (HR) for VA or SCA.

Results

A total of 54,303 diabetic patients were screened with 1,037 of them in the HE group, and 4,148 in the control group. During a mean follow-up period of 3.3±2.5 years, 29 VA/SCA events had occurred. Compared to the control group, the HE group had a higher incidence of VA/SCA (adjusted HR: 2.42, p=0.04). Diabetic patients medicated with insulin for glycemic control increased the risk of VA/SCA compared to those without insulin (adjusted HR: 3.05, p=0.01).

Kaplan-Meier survival curves

Conclusions

HEs in patients with diabetes increased the risks of VA and SCA compared to those without. Their use of insulin also independently increased the risk of VA/SCA.

P2564Levosimendan shortens action potential duration, decreases alternans threshold and prevents ventricular arrhythmia during therapeutic hypothermia in isolated rabbit hearts

Background

Therapeutic hypothermia (TH) increases the susceptibility to ventricular arrhythmias (VA) by prolonging action potential duration (APD) and facilitating arrhythmogenic spatially discordant alternans (SDA). The calcium sensitizer levosimendan has been reported to shorten APD by enhancing ATP-sensitive K current. We hypothesize that levosimendan might shorten the already prolonged APD during TH, decreasing SDA threshold, and prevent the occurrence of VA.

Methods

Langendorff-perfused isolated rabbit hearts were subjected to 15-min TH (30°C) followed by 30-min treatment with levosimendan (0.5 μM, n=9) or vehicle (n=8). Using an optical mapping system, epicardial APD was evaluated by S1 pacing. SDA threshold was defined as the longest pacing cycle length (PCL) that induced SDA phenomenon. Ventricular fibrillation (VF) inducibility was evaluated by burst pacing for 30 s using the shortest PCL that achieved 1:1 ventricular capture.

Results

Levosimendan shortened the ventricular APD (at PCL 300 ms, from 229±9 ms to 211±18 ms, p=0.02) and decrease the SDA threshold (from 327±88 ms to 311±68 ms, p=0.001) during TH. The VF inducibility was decreased by levosimendan from 39±30% at 30°C to 14±12% after levosimendan infusion. In control hearts, the APD (p=0.75), SDA threshold (p=ns) and VF inducibility (p=0.12) were not changed by vehicle during TH.

Conclusions

Levosimendan protects the hearts against VA during TH by shortening APD and decreasing SDA threshold. Enhancing ATP-sensitive K current with levosimendan might be a novel approach to prevent VA during TH.

Genetic analysis of surgical margins in oral cavity cancer

BACKGROUND

A histological, tumour-free surgical margin does not guarantee recurrence-free survival in patients with cancer. This study investigated the association between microsatellite alteration in tumour-free surgical margins and local recurrence in patients with oral cavity squamous cell carcinoma.

METHODS

Patients with histologically confirmed oral cavity squamous cell carcinoma were enrolled in this prospective study. Cancerous specimens, corresponding surgical margins and peripheral blood were obtained. Microsatellite alteration was investigated using six dinucleotide microsatellite markers. All samples were amplified by PCR, followed by automatic fragment analysis.

RESULTS

Microsatellite alteration was identified in 100 specimens (69·0 per cent) from 145 patients. Among them, 85 specimens carried loss of heterozygosity, whereas 55 had microsatellite instability (MSI). Patients with MSI at the surgical margin had a higher risk of local recurrence on multivariable analysis (odds ratio 7·17, 95 per cent c.i. 3·49 to 14·73).

CONCLUSION

Molecular assessment of surgical margins can help identify patients at risk of local recurrence.

Critical behavior in tetragonal antiperovskite GeNFe3 with a frustrated ferromagnetic state

Tetragonal GeNFe₃ has a second-order ferromagnetic (FM) to paramagnetic transition at 76 K. Our integrated investigations indicate that the ground FM state is frustrated and the tetragonal symmetry is retained below 550 K based on the results of variable temperature X-ray diffraction. Critical behavior was analyzed by a systematic bulk magnetization study. The estimated critical exponents by three different methods (modified Arrott plot, the Kouvel-Fisher method, and critical isotherm analysis) conformably suggest that long-range magnetic coupling described by mean-field (MF) theoretical model is dominant in GeNFe₃. The experimental M-T-H data collapse into two independent branches according to the scaling equations m = f_±(h) with the renormalized magnetization m = ε^-βM(H, ε) and the magnetic field h = Hε^-(β+γ). The exchange distance is estimated as J(r) ∼ r^-4.8 on the basis of the β and γ values, which lies between the long-range MF model (r^-4.5) and the short-range 3D Heisenberg (3DH) model (r^-5). Our results indicate that the competition between local magnetic moments of iron 3d electronic state and itinerant covalent interactions of N-Fe bonds should be responsible for critical behavior in this system.

Large Positive Thermal Expansion and Small Band Gap in Double-ReO3-Type Compound NaSbF6

Double-ReO₃-type structure compound NaSbF₆ undergoes a low-temperature rhombohedral to high-temperature cubic phase between 303 and 323 K, as revealed by temperature-dependent X-ray diffractions. Although many double-ReO₃-type fluorides exhibit either low thermal expansion or negative thermal expansion (NTE), NaSbF₆ exhibits positive thermal expansion (PTE) with a large volumetric coefficient of thermal expansion, α_v = 62 ppm/K, in its cubic phase. Raman spectroscopy reveals that the low-frequency transverse vibration of fluorine atoms is stiffened in NaSbF₆, compared with the typical NTE compound CaZrF₆ with the same structure. The related weak contraction associated with the polyhedral rocking would be overcome by the notable elongation of the Na-F bond length on heating, thus leading to the large volumetric PTE. Unlike ScF₃ and CaZrF₆ which are insulators with a wide band gap, a relative small band gap of 3.76 eV was observed in NaSbF₆. The small band gap can be attributed to the hybridization between the Sb 5s and F 2p orbitals.

Hidden lattice instabilities as origin of the conductive interface between insulating LaAlO3 and SrTiO3

The metallic interface between insulating LaAlO₃ and SrTiO₃ opens up the field of oxide electronics. With more than a decade of researches on this heterostructure, the origin of the interfacial conductivity, however, remains unsettled. Here we resolve this long-standing puzzle by atomic-scale observation of electron-gas formation for screening hidden lattice instabilities, rejuvenated near the interface by epitaxial strain. Using atomic-resolution imaging and electron spectroscopy, the generally accepted notions of polar catastrophe and cation intermixing for the metallic interface are discounted. Instead, the conductivity onset at the critical thickness of 4-unit cell LaAlO₃ on SrTiO₃ substrate is accompanied with head-to-head ferroelectric-like polarizations across the interface due to strain-rejuvenated ferroelectric-like instabilities in the materials. The divergent depolarization fields of the head-to-head polarizations cast the interface into an electron reservoir, forming screening electron gas in SrTiO₃ with LaAlO₃ hosting complementary localized holes. The ferroelectric-like polarizations and electron–hole juxtaposition reveal the cooperative nature of metallic LaAlO₃/SrTiO₃.

The origin of interfacial conductivity between two insulating oxides, LaAlO₃ and SrTiO₃, remains elusive despite a long time research. Here, Lee et al. report atomic-scale observation of electron-gas formation for screening hidden ferroelectric-like lattice instabilities, discounting the role of polar catastrophe and cation intermixing.

β-Catenin overexpression causes an increase in inflammatory cytokines and NF-κB activation in cardiomyocytes

β-Catenin has been implicated in various developmental and physiological processes. Defective Wnt signaling can result in different cardiac and vascular abnormalities and is activated under pathological conditions such as inflammation and obesity. In this study, roles of β-catenin in inflammation in cardiomyocytes were investigated. 10 samples from hearts of patients with acute infarction and 10 from normal ones were collected in order to access roles of β-catenin in cardiomyocytes. H9c2 cardiomyoblasts and primary neonatal rat cardiomyocytes were transfected with porcine cytomegalovirus (pCMV)-β-catenin plasmid in order to overexpress β-catenin. Protein level of β-catenin protein was increased in human acute infarction tissues compared to ones from normal patients. The transcription factor had increased nuclear localization in cardiomyocytes of the Wistar rats with cardiac hypertension. Furthermore, expression of fibrosis protein markers increased. Protein expression of β-catenin was increased in human acute infarction inflammatory heart tissues and in hearts of inflammatory obesity rats. After pCMV-β-catenin plasmid was transfected in a dose-dependent manner, inflammation protein markers, TNF-α and IL-8, were upregulated in hypertensive neonatal rat cardiomyocytes and H9c2 cardiomyoblasts. In addition, overexpression of β-catenin induced activation and nuclear localization of NF-κB. Therefore, β-catenin is a potential molecular target for treatment of inflammation and fibrosis in cardiomyocytes.

Practical use of povidone-iodine antiseptic in the maintenance of oral health and in the prevention and treatment of common oropharyngeal infections

AIMS

To better inform medical practitioners on the role of antiseptics in oropharyngeal health and disease, this article focuses on povidone-iodine (PVP-I), an established and widely-available antiseptic agent.

METHODOLOGY

Review of the anti-infective profile, efficacy and safety of PVP-I in managing common upper respiratory tract infections such as the common cold, influenza and tonsillo-pharyngitis, as well as oral complications resulting from cancer treatment (oral mucositis), and dental conditions (periodontitis, caries).

RESULTS

Antiseptics with broad-spectrum anti-infective activity and low resistance potential offer an attractive option in both infection control and prevention. While there is some evidence of benefit of antiseptics in a variety of clinical settings that include dental and oral hygiene, dermatology, oncology, and pulmonology, there appears to be discordance between the evidence-base and practice. This is especially apparent in the management and prevention of oropharyngeal infections, for which the use of antiseptics varies considerably between clinical practices, and is in marked contrast to their dermal application, where they are extensively used as both a prophylaxis and a treatment of skin and wound infections, thus minimising the use of antibiotics.

CONCLUSION

The link between oral and oropharyngeal health status and susceptibility to infection has long been recognised. The high rates of antibiotic misuse and subsequent development of bacterial resistance (e.g. increasing vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)) in large parts of the world, especially across Asia Pacific, highlight the need for identifying alternative antimicrobials that would minimise the use of these medications. This, together with recent large-scale outbreaks of, for example, avian and swine influenza virus, further underline the importance of an increasing armamentarium for infection prevention and control.

Risk factors and outcome for colistin-resistant Acinetobacter nosocomialis bacteraemia in patients without previous colistin exposure

The clinical characteristics of patients with colistin-resistant Acinetobacter baumannii bacteraemia have been documented, but those of patients with bacteraemia caused by other Acinetobacter species remain unknown. Previous exposure to colistin has been shown to be associated with the emergence of colistin resistance, but may be not the only predisposing factor. In the current study, we highlight the risk and outcome of patients without previous exposure to colistin who acquired colistin-resistant Acinetobacter nosocomialis (ColRAN) bacteraemia. This 11-year single-centre retrospective study analysed 58 patients with ColRAN bacteraemia and 213 patients with colistin-susceptible A. nosocomialis (ColSAN) bacteraemia. Antimicrobial susceptibilities were determined with an agar dilution method. The clonal relationship of ColRAN isolates was determined with pulsed-field gel electrophoresis. A conjugation mating-out assay was conducted to delineate the potential transfer of colistin resistance genes. Multivariable analysis was performed to evaluate the risk factors for ColRAN bacteraemia. Chronic obstructive pulmonary disease (COPD) was independently associated with ColRAN bacteraemia (OR 3.04; 95% CI 1.45-6.37; p 0.003). Patients with ColRAN bacteraemia had higher APACHE II scores, but the two groups showed no significant differences in 14-day mortality (10.3% vs. 10.3%) or 28-day mortality (15.5% vs. 15.0%). ColRAN isolates had greater resistance than ColSAN isolates to all antimicrobial agents except for ciprofloxacin (0% vs. 6.6%). There were 16 different ColRAN pulsotypes, and two major clones were found. Colistin resistance did not transfer to colistin-susceptible A. baumannii or A. nosocomialis. These results show that COPD is an independent risk factor for acquisition of ColRAN bacteraemia. The mortality rates were similar between patients with ColRAN and ColSAN bacteraemia.

Applying ATP bioluminescence to design and evaluate a successful new intensive care unit cleaning programme

This was a two-phase prospective intervention study in the cardiology intensive care unit (CICU) and medical intensive care unit (MICU) and of a public 1800-bed medical centre in Taiwan. In phase I, cleaning efficacy was monitored by ATP bioluminescence after daily morning cleaning, and only 43.9% of 221 tested surfaces passed. The baseline data were used to define an intervention consisting of a new cleaning protocol as well as a new education/training programme. In phase II, following the intervention, 88.1% of 270 surfaces were found to be clean. The combined infection rate in the CICU and MICU showed a statistically significant decrease of 49.7%.

Photobacterium damselae subsp. piscicida responds to antimicrobial peptides through phage-shock-protein A (PspA)-related extracytoplasmic stress response system

AIMS

To investigate whether Photobacterium damselae subsp. piscicida (Phdp) can sense and directly respond to the presence of cationic antimicrobial peptides (AMPs).

METHODS AND RESULTS

We performed proteomic methodologies to investigate the responsive proteins of Phdp on exposure to AMP Q6. Proteins significantly altered were analysed by two-dimensional gel electrophoresis (2-DE) and LC-ESI-Q-TOF MS/MS, thus resulting in five outer membrane proteins (OMPs), seven inner membrane proteins (IMPs) and 17 cytoplasmic proteins (CPs) identified. Quantitative real-time PCR was also applied to monitor the mRNA expression level of these target proteins.

CONCLUSIONS

COG analysis revealed that upon exposure to AMP Q6, the majority of the upregulated proteins were involved in signal transduction mechanism, carbohydrate transport and metabolism, post-translational modification, protein turnover and chaperones, while the downregulated proteins were mainly related to energy production and conversion. Among them, phage-shock-protein A (PspA)-related stress response system was considered to play a crucial role.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the best of our knowledge, this is the first report elucidating Phdp AMP-response mechanism using proteomics approach. AMP-responsive proteins identified in this study could serve as attractive targets for developing more effective antimicrobial agents against Phdp and other marine bacterial pathogens.

Clinical manifestations and prognostic factors of Morganella morganii bacteremia

Although Morganella morganii causes a variety of clinical infections, there are limited studies on M. morganii bacteremia after the year 2000. A total of 109 patients with M. morganii bacteremia at a medical center in Taiwan from 2003 to 2012 were studied. Among them, 30.3 % had polymicrobial bacteremia and 75.2 % had community-acquired infection. The most common underlying diseases were hypertension (62.4 %) and diabetes mellitus (38.5 %). The urinary tract (41.3 %) was the major portal of entry, followed by the hepatobiliary tract (27.5 %), skin and soft tissue (21.1 %), and primary bacteremia (10.1 %). Susceptibility testing of M. morganii isolates showed ubiquitous resistance to first-generation cephalosporins and ampicillin-clavulanate; resistance rates to gentamicin, piperacillin-tazobactam, and ciprofloxacin were 30.3 %, 1.8 %, and 10.1 %, respectively. Overall, the 14-day mortality was 14.7 %. Univariate analysis revealed that elevated blood urea nitrogen (BUN) values [p = 0.0137, odds ratio (OR) 5.26], intensive care unit (ICU) admission (p = 0.011, OR 4.4), and higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores (p < 0.001, OR 1.62) were significantly associated with mortality. The APACHE II score remained the only significant risk factor for mortality in multivariate analysis (p = 0.0012, OR 1.55). In conclusion, M. morganii bacteremia patients were mostly elderly, with one or more comorbidities. Most of the patients had community-acquired infection via the urinary and hepatobiliary tracts. Furthermore, prognosis can be predicted according to disease severity measured by the APACHE II score.

Phase I study of BAY 94-9027, a PEGylated B-domain-deleted recombinant factor VIII with an extended half-life, in subjects with hemophilia A

BACKGROUND

BAY 94-9027 is a B-domain-deleted recombinant factor VIII (rFVIII) with site-specific attachment of poly(ethylene glycol) that has shown an extended half-life in animal models of hemophilia.

OBJECTIVES

To assess the pharmacokinetics and safety of BAY 94-9027 after single and repeated administration in subjects with severe hemophilia A.

PATIENTS/METHODS

This 8-week, prospective, multicenter, open-label, phase I trial was conducted in 14 subjects aged 21–58 years with FVIII of < 1%, ≥ 150 days of exposure to FVIII, and no history of FVIII inhibitors. After a ≥ 3-day washout, subjects received a single dose of sucrose-formulated rFVIII (rFVIII-FS) (cohort 1 [n = 7], 25 IU kg−1; cohort 2 [n = 7], 50 IU kg−1) for a 48-h pharmacokinetic (PK) study. After another ≥ 3-day washout, cohort 1 received twice-weekly BAY 94-9027 at 25 IU kg−1 (16 doses), and cohort 2 received once-weekly BAY 94-9027 at 60 IU kg−1 (nine doses). A 168-h PK study was performed after the first and last BAY 94-9027 doses.

RESULTS

BAY 94-9027 showed equivalent recovery and an improved PK profile vs. rFVIII-FS, with a half-life of ~ 19 h (vs. ~ 13.0 h for rFVIII-FS). BAY 94-9027 was well tolerated, and no immunogenicity was observed.

CONCLUSIONS

This phase I study demonstrates that BAY 94-9027 has an extended half-life in subjects with hemophilia A and, after multiple dosing, was well tolerated with no immunogenicity during the 8-week trial. A phase III study in a larger number of subjects is underway to fully characterize how this prolonged half-life will permit less frequent prophylaxis dosing for patients with hemophilia.

Modulation of neurotrophin signaling by monoclonal antibodies

The neurotrophin family is comprised of the structurally related secreted proteins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophine-4 (NT-4). They bind and activate the tyrosine kinase receptors Trk A, B, and C in a ligand-specific manner and additionally bind a shared p75NTR receptor. The neurotrophins were originally defined by their ability to support the survival and maturation of embryonic neurons. However, they also control important physiological functions of the adult nervous system including learning and memory, sensation, and energy homeostasis. For example, NGF/trkA signaling is critical for normal and pathological sensation of pain. Likewise, the BDNF/trkB pathway controls feeding and metabolism, and its dysfunction leads to severe obesity. Antibodies can modulate neurotrophin signaling. Thus, NGF blocking agents can attenuate pain in several animal models, and a recombinant humanized NGF blocking antibody (Tanezumab) has shown promising results in human clinical trials for osteoarthritic pain. On the other hand trkB agonist antibodies can modulate food intake and body weight in rodents and nonhuman primates. The power of monoclonal antibodies to modulate neurotrophin signaling promises to turn the rich biological insights into novel human medicines.

Treatment effects in a transgenic mouse model of Alzheimer's disease: a magnetic resonance spectroscopy study after passive immunization

Despite the enormous public health impact of Alzheimer's disease (AD), no disease-modifying treatment has yet been proven to be efficacious in humans. A rate-limiting step in the discovery of potential therapies for humans is the absence of efficient non-invasive methods of evaluating drugs in animal models of disease. Magnetic resonance spectroscopy (MRS) provides a non-invasive way to evaluate the animals at baseline, at the end of treatment, and serially to better understand treatment effects. In this study, MRS was assessed as potential outcome measure for detecting disease modification in a transgenic mouse model of AD. Passive immunization with two different antibodies, which have been previously shown to reduce plaque accumulation in transgenic AD mice, was used as intervention. Treatment effects were detected by MRS, and the most striking finding was attenuation of myo-inositol (mIns) increases in APP-PS1 mice with both treatments. Additionally, a dose-dependent effect was observed with one of the treatments for mIns. MRS appears to be a valid in vivo measure of anti-Aβ therapeutic efficacy in pre-clinical studies. Because it is noninvasive, and can detect treatment effects, use of MRS-based endpoints could substantially accelerate drug discovery.

SCUBE3 is an endogenous TGF-β receptor ligand and regulates the epithelial-mesenchymal transition in lung cancer

Signal peptide-CUB-EGF-like domain-containing protein 3 (SCUBE3) is a secreted glycoprotein that is overexpressed in lung cancer tumor tissues and is correlated with the invasive ability in a lung cancer cell line model. These observations suggest that SCUBE3 may have a role in lung cancer progression. By exogenous SCUBE3 treatment or knockdown of SCUBE3 expression, we found that SCUBE3 could promote lung cancer cell mobility and invasiveness. Knockdown of SCUBE3 expression also suppressed tumorigenesis and cancer metastasis in vivo. The secreted SCUBE3 proteins were cleaved by gelatinases (matrix metalloprotease-2 (MMP-2) and MMP-9) in media to release two major fragments: the N-terminal epidermal growth factor-like repeats and the C-terminal complement proteins C1r/C1s, Uegf and Bmp1 (CUB) domain. Both the purified SCUBE3 protein and the C-terminal CUB domain fragment, bound to transforming growth factor-β (TGF-β) type II receptor through the C-terminal CUB domain, activated TGF-β signaling and triggered the epithelial-mesenchymal transition (EMT). This process includes the induction of Smad2/3 phosphorylation, the increase of Smad2/3 transcriptional activity and the upregulation of the expression of target genes involved in EMT and cancer progression (such as TGF-β1, MMP-2, MMP-9, plasminogen activator inhibitor type-1, vascular endothelial growth factor, Snail and Slug), thus promoting cancer cell mobility and invasion. In conclusion, in lung cancer cells, SCUBE3 could serve as an endogenous autocrine and paracrine ligand of TGF-β type II receptor, which could regulate TGF-β receptor signaling and modulate EMT and cancer progression.

Productivity, utilization, and nutritive quality of dallisgrass (Paspalum dilatatum) as influenced by stocking density and rest period under continuous or rotational stocking

Dallisgrass (Paspalum dilatatum) is well adapted to the Black Belt physiographic region of the southeastern United States, and information on its productivity and nutritive quality as influenced by grazing management is needed. In a 2-yr grazing experiment, replicate 0.40-ha paddocks in established dallisgrass pasture were continuously stocked, or replicate 0.40-ha paddocks were subdivided into two 0.20-ha (RS2), three 0.13-ha (RS3), or four 0.10-ha (RS4) cells and rotationally stocked with yearling beef steers. Individual cells within the RS2, RS3, and RS4 treatments were stocked for 7 d followed by 7, 14, or 21 d of rest, respectively. In 2007, 3 Angus × Simmental crossbred steers (initial BW, 354 ± 6 kg) were assigned randomly to each paddock on July 16; in 2008, 3 Angus × Simmental crossbred steers (initial BW, 310 ± 6 kg) were assigned randomly to each paddock on July 14. In 2007, there was no effect (P = 0.25) of stocking treatment on ADG. Steers grazing RS4, RS2, and continuously stocked paddocks had 106 (P = 0.01), 86 (P = 0.03), and 83 (P = 0.03) kg greater total BW gain per ha, respectively, than steers grazing RS3 paddocks. In 2008, there were no differences among treatments in ADG (P = 0.43) or total BW gain per ha (P = 0.90). Correlation and regression analyses revealed positive associations between steer performance and forage concentration of CP, areal mass (kg/ha) of forage DM, and areal mass of forage CP. Results indicate that productivity and quality of dallisgrass for stocker cattle production were comparable between continuous and rotational-stocking methods.

Atomic structure of the Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3)) surface: From scanning tunneling microscopy observation to theoretical study

The atomic structure of the Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 degrees surface is studied by scanning tunneling microscopy (STM) and the density functional theory (DFT) calculations. Our STM images have shown a structure which is different from the widely accepted honeycomb-chained-triangle (HCT) model before. The structure is similar to the inequivalent triangle (IET) model found for the Ag/Si(111)-(sq.rt.(3) x sq.rt(3))R30 degrees surface. This model proposed two types of silver triangles with different sizes in the unit cell, corresponding to the bright spots and the dark spots in the STM image. A distinguishable hexagonal pattern of the IET structure was well disclosed in the temperature range from 100 to 473 K in our STM studies for Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 degrees. Furthermore, the result of the DFT calculations showed that the IET structure is 0.20 eV energetically more stable than the HCT model. Besides, the Ge triangles, which were not disclosed in earlier STM research, are found in this study.

MODULATION OF MDR-1 GENE BY MIF AND GSTpi WITH DRUG RESISTANCE GENERATION IN HORMONE INDEPENDENT PROSTATE CANCER

The expression of MIF and GSTpi were upregulated in prostate cancer cells with mulitdrug resistant phenotype. The aim of this study is to determine the relationship between these genes and multidrug resistance (mdr-1) gene in acquired multidrug resistance of prostate cancer. The expression of MIF, GSTpi and gp-170 in multidrug resistant (MDR) subline or native cells were determined using flow cytometry and western blotting. The mRNA level of various genes was analyzed with RT-PCR method. The chemosensitivity of tumor cells and stable transfectants to paclitaxel was measured using MTT (tetrazolium bromide) assay. The protein levels of MIF, GSTpi and gp-170 increased in MDR sublines of prostate cancer when compared with their parental cells. The MIF and GSTpi stable transfectants expressed higher MIF and GSTpi protein levels than their parental cells in western blotting analysis, respectively. The expression of mdr-1 gene and the production of pg-170 were also increased in either MIF or GSTpi stable transfectants when compared with vector control by using RT-PCR and flow cytometric analysis. The MTT results demonstrated that the increased chemoresistance was correlated with the increased production of gp-170 protein in either MIF or GSTpi transfectants. The upregulation of MIF and GSTpi during the development of acquired drug resistance of hormone independent prostate cancer may simultaneously and partially modulate the activation of gp-170.

Sequence dependent electron transport in wet DNA: ab initio and molecular dynamics studies

We combine molecular dynamics simulations and density functional theory to analyze the electrical structure and transmission probability in four different DNA sequences under physiological conditions. The conductance in these sequences is primarily controlled by interstrand and intrastrand coupling between low-energy guanine orbitals. Insertion of adenine-thymine base pairs between the guanine-cytosine rich domains acts as a tunneling barrier. Our theory explains recent length dependent conductance data for individual DNA molecules in water.

A scanning tunneling microscopy study of distyrylbenzene on Ag/Ge(111)-(sqr rt of 3 x sqr rt of 3)R30 degrees

The adsorption and self-organized monolayers of trans,trans-distyrylbenzene (tt-DSB) and cis,cis-distyrylbenzene (cc-DSB) on Ag/Ge(111)-(sqr rt of 3 x sqr rt of 3)R30 degrees (Ag/Ge(111)-sqr rt of 3) were studied by low-temperature scanning tunneling microscopy (STM) in ultrahigh vacuum. tt-DSB and cc-DSB overlayers were prepared by vapor deposition at a substrate temperature of 200 K and imaged after the samples were cooled to 100 K. High-resolution images allow identification of the internal structure of individual tt-DSB molecules with three phenyl rings and their molecular arrangements on the Ag/Ge(111)-sqr rt of 3 surface. It is found that the intermolecular distance between two terminal phenyl rings in tt-DSB is about twice the lattice constant of Ag/Ge(111)-sqr rt of 3. Such a lattice match makes Ag/Ge(111)-sqr rt of 3 an ideal substrate for tt-DSB self-organization and the formation of a (3 x 1) overlayer unit cell. The structural model and the molecule registry corresponding to STM images for the adlayers of tt-DSB on Ag/Ge(111)-sqr rt of 3 are proposed and discussed. For cc-DSB adsorption on Ag/Ge(111)-sqr rt of 3, uniform molecular overlayers with two discernible molecular images corresponding to two major types of cc-DSB conformers were observed. The coexistence of multiple conformers and the mismatch of molecular dimension of cc-DSB with the substrate unit cell length limit the growth of large cc-DSB domains.

Alfalfa nutritive quality for ruminant livestock as influenced by ambient air quality in west-central Alberta

Alfalfa (Medicago sativa) nutritive quality response to ambient ozone (O(3)), sulfur dioxide (SO(2)) and oxides of nitrogen (NO(x)) were assessed at three locations in west-central Alberta, Canada (1998-2002). Yield data were segregated into high and low relative to overall median yield. Ozone concentrations (hourly median and 95th-percentile) and precipitation (P) contributed 69 and 29%, respectively, to the variability in crude protein (CP) concentration in low-yielding alfalfa, whereas mean temperature (T) and relative humidity (RH) collectively influenced 98% of the variation in CP in high-yielding alfalfa. Three-fourths of the accounted variation in relative feed value (RFV) of low-yielding alfalfa was attributable to P, T and RH, whereas median and 95th-percentile hourly O(3) concentrations and SO(2) and NO(x) exposure integrals contributed 25%. In contrast, air quality, (mainly O(3)) influenced 86% of the accounted variation in RFV of high-yielding alfalfa, and T and P collectively contributed 14%.

Electronic minibands in complex basis superlattices: a numerically stable calculation

A numerically stable method for accurately determining the energy minibands of superlattices with arbitrary numbers of layers per cell is presented. Using a graph model with tangent and secant functions, we derive a set of concise and closed-form miniband edge equations for determining the miniband structure using topology theory. With the present method, it is not necessary to calculate the cosine of the Bloch phase, which may show a numerical overflow in calculation. Numerical results show that use of the miniband edge equations has better numerical stability than traditional methods in calculating the minibands of complex basis superlattices.

Treatment of oral submucous fibrosis by collagenase: effects on oral opening and eating function

OBJECTIVE

Patients with oral submucous fibrosis (OSF) suffer from the limitation of the oral opening. The aim of this study was to develop a simple and rapid method to improve the opening of the oral cavity and determine its effect on the incidence of developing oral carcinoma.

METHODS

We first induced an OSF-like lesion in rabbits which histopathologically resembles OSF in betel nut chewers and evaluated the effects of exogenous collagenase on these lesions. We then applied the collagenase treatment regimen to patients with OSF.

RESULTS

Endogenous collagenase activities in normal oral mucosa of patients exhibited 3- to 5-fold higher levels than that of OSF tissues. The collagenase treatment not only resulted in a significant improvement of oral opening, but patients also experienced a striking reduction in hypersensitivity to spices, sour, cold, and heat which helped restore eating function. Sub-mucosal fibrous proliferation, persistently good vascularization, and a mild increase in thickness of the sub-mucosal fibrous tissues were noticed 10 months after collagenase treatment. Within the 2-year follow-up period none of the treated patients developed an oral squamous cell carcinoma.

CONCLUSION

A reduced content of functional collagenase observed in OSF mucosa of patients might be one mechanism responsible for collagen accumulation. Intervention of OSF by collagenase treatment at the early stage may reduce the incidence of developing oral carcinoma.

Areca nut extracts reduce the intracellular reactive oxygen species and release of myeloperoxidase by human polymorphonuclear leukocytes

BACKGROUND AND OBJECTIVE

Polymorphonuclear leukocytes (PMN) represent the first line of host defense. Areca nut extract inhibits the bactericidal activity of, and the release of superoxide anion (O2- ) by, PMN. This study investigated the effects of areca nut extract on the intracellular production of reactive oxygen species (ROS) and on the extracellular release of lysosomal enzyme, myeloperoxidase (MPO), by PMN. The effects of arecoline, a principal component of areca nut, were also examined.

MATERIAL AND METHODS

Human PMN were treated with various concentrations of areca nut extract or arecoline followed by treatment with Hanks' balanced salt solution, with or without cytochalasin B and fMet-Leu-Phe (CB/fMLP). The viability of PMN was determined using propidium iodide staining and flow cytometry. The presence of intracellular ROS was determined using 2',7'-dichlorofluorescin diacetate and fluorometry. MPO release was determined using a substrate assay.

RESULTS

Areca nut extract (25 and 50 microg/ml) significantly decreased the viability of PMN. The intracellular levels of ROS and the extracellular release of MPO were induced in PMN by CB/fMLP. Exposure of PMN to areca nut extract (up to 25 microg/ml) or to arecoline (up to 2 mg/ml) did not directly affect the levels of ROS and MPO activity. However, under conditions that did not affect the viability of PMN, the ability of CB/fMLP to trigger production of intracellular ROS and release of MPO in human PMN was significantly suppressed by areca nut extract and arecoline.

CONCLUSION

Areca nut impaired the activation of PMN by CB/fMLP that might decrease the effectiveness of PMN in the host defense. Alternatively, exposure of PMN to areca nut extract could decrease the capacity of PMN to damage tissues.

Prevalence of sporadic and familial haemophilia

In an analysis of 804 haemophilia pedigrees, mild to moderate haemophilia A or B was found to be clearly familial in 70% of cases, severe haemophilia B in 57% of cases and severe haemophilia A in 45% of cases. The rest of the patients were 'sporadic' i.e., either isolated cases or brothers in the first affected sibship. In sporadic families, 88% of mothers but only 19% of maternal grandmothers had the relevant mutation in their white blood cells. Among patients with familial haemophilia, half the patients with mild haemophilia and those with severe haemophilia B had a direct male ancestor with haemophilia, but only 28% of patients with severe haemophilia A had such a progenitor.

Direct evidence of attempted beta cell regeneration in an 89-year-old patient with recent-onset type 1 diabetes

AIMS/HYPOTHESIS

We investigated whether there was evidence of attempted beta cell regeneration in the pancreas obtained from a patient with recent-onset type 1 diabetes, and if so by what mechanism this occurred.

SUBJECTS, MATERIALS AND METHODS

We examined pancreas tissue from a lean 89-year-old patient (BMI 18.0 kg/m(2)) with recent-onset type 1 diabetes who had had a distal pancreatectomy to remove a low-grade pancreatic intraepithelial neoplasia.

RESULTS

In the tumour-free tissue, the fractional beta cell area was 0.54+/-0.2% of pancreas area (about one-third of that in non-diabetic humans). CD3-positive T lymphocytes and macrophages had infiltrated the majority of the islets. Subclassification of the T cell population revealed a predominance of CD8-positive cells over CD4-positive cells. Beta cell apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling [TUNEL] staining) was greatly increased, consistent with ongoing immune-mediated beta cell destruction. There was also a marked increase (more than approximately 100-fold) in the frequency of beta cell replication (0.69+/-0.15% Ki67-positive beta cells) in all blocks examined.

CONCLUSIONS/INTERPRETATION

The present report provides direct evidence of attempted beta cell regeneration through the mechanism of beta cell replication in a case of newly diagnosed type 1 diabetes, and affirms that beta cell apoptosis is an important mechanism for beta cell loss in type 1 diabetes.

Growth and nutritive quality of Poa pratensis as influenced by ozone and competition

Interspecific plant competition has been hypothesized to alter effects of early-season ozone (O3) stress. A phytometer-based approach was utilized to investigate O3 effects on growth and nutritive quality of Poa pratensis grown in monoculture and in mixed cultures with four competitor-plant species (Anthoxanthum odoratum, Achillea millefolium, Rumex acetosa and Veronica chamaedrys). Mesocosms were exposed during April/May 2000-2002 to charcoal-filtered air+25 ppb O3 (control) or non-filtered air+50 ppb O3 (elevated O3). Biomass production was not affected by O3, but foliar injury symptoms were observed in May 2002. Early-season O3 exposure decreased relative food value of P. pratensis by an average of 8%, which is sufficient to have nutritional implications for its utilization by herbivores. However, forage quality response to O3 was not changed by interspecific competition. Lack of injury and nutritive quality response in P. pratensis harvested in September may reflect recovery from early-season O3 exposure.

Correlated hybridization in transition-metal complexes

We apply local orbital basis density functional theory (using SIESTA) coupled with a mapping to the Anderson impurity model to estimate the Coulomb assisted or correlated hybridization between transition-metal orbitals and ligand orbitals for a number of molecular complexes. We find remarkably high values which can have several physical implications including (i) renormalization of effective single-band or multiband Hubbard model parameters for the cuprates and, potentially, elemental iron, and (ii) spin polarizing molecular transistors.

Apolipoprotein E, angiotensin-converting enzyme and kallikrein gene polymorphisms and the risk of Alzheimer's disease and vascular dementia

Lipoproteins and vascular factors may play roles in the development of Alzheimer's disease (AD) and/or vascular dementia (VaD). In this study, odd ratios (ORs) and 95% confidence intervals (CIs) for apolipoprotein E (APOE), angiotensin-converting enzyme (ACE), and kallikrein (KLK1) polymorphisms were computed to test their association with the disease by a case-control study. The risk of AD was significantly increased for individuals with APOE varepsilon4 allele (OR = 3.73, 95% CI = 2.38-5.98). The risk of AD was also significant for people with ACE DD genotype, D allele, or T-D haplotype [OR (95% CI) = 4.29 (1.96-10.23), 1.90 (1.35-2.70), or 2.91 (1.71-5.10), respectively]. The above association between ACE-VaD was also strong (p = 0.0012, 0.0050, 0.0007, respectively). Reporter constructs containing the -240 A or T allele displayed similar transcriptional activity in both HEK-293 and IMR-32 cells. Thus, another putative pathogenic marker that is linked with the Alu D allele might affect the risk of AD and VaD in Taiwan.

Heat shock protein 70 and tumor necrosis factor alpha in Taiwanese patients with dementia

This study was to determine whether polymorphisms of heat shock protein 70-1 (HSP70-1) and tumor necrosis factor alpha (TNF-alpha) are associated with the risk of Alzheimer's disease (AD) and vascular dementia (VaD). Using the criteria of the NINCDS-ADRDA and NINDS-AIREN, 125 AD patients, 57 VaD patients and 109 ethnically matched nondemented controls were enrolled. The HSP70-1 -110 A/C and TNF-alpha -1031 T/C, -863 C/A and -857 C/T polymorphisms were analyzed by means of genotype or haplotype association methods. None of the four genotypes examined showed a statistically significant difference in genotype distribution between the AD cases and controls. However, the HSP70-1 -110 CC genotype occurred more frequently among AD cases (p=0.0821; odds ratio: 2.08; 95% confidence interval, CI: 0.92-4.98). The overall genotype distribution among the VaD cases tended to be different at the HSP70-1 -110 and TNF-alpha -1031 sites (p=0.0604 and 0.0316, respectively). The HSP70-1 -110 CC genotype was more frequent (p=0.0459), and the association of the -110 CC genotype with VaD was evident (p=0.0207; odds ratio: 3.22; 95% CI: 1.20-8.87). The more frequent TNF-alpha -1031 TC genotype (p=0.0614) was also evidently associated with VaD (p=0.0209; odds ratio: 2.32; 95% CI: 1.14-4.78). Multivariate analysis demonstrated the synergistic effect of the HSP70-1 -110 CC and TNF-alpha -1031 TC/CC genotypes on VaD (p=0.0091; odds ratio: 10.09; 95% CI: 2.01-75.97). Haplotype analysis among TNF-alpha -1031, -863, -857 sites revealed that -1031C-857C may act as a risk haplotype among VaD cases (p=0.0132, odds ratio: 2.26; 95% CI: 1.19-4.33). Our results suggest a potential protective role for HSP70 in both VaD and AD, whereas TNF-alpha may act as a risk factor only for VaD, and not for AD.

Altering the crystal morphology of silicalite-1 through microemulsion-based synthesis

The crystal morphology of silicalite-1 was adjusted through a microemulsion-based hydrothermal synthesis. The surfactant cetyltrimethylammonium bromide (CTAB) with cosurfactant butanol was used to form water-in-oil microemulsions containing the silicalite-1 synthesis gel. The crystal morphology of silicalite-1 was adjusted from coffin-shaped to novel rod-shaped and to irregular-shaped nanoparticles by varying the microemulsion composition. Silicalite-1 synthesized in the microemulsion has a smaller size and a more narrow size distribution than that produced by conventional synthesis without the microemulsion. The novel morphology of silicalite-1 may facilitate assembly into films and find applications in separation and catalysis.

Molecular dynamics simulations of various coronavirus main proteinases

In this study, two homology models (denoted as MproST and MproSH) of main proteinase (Mpro) from the novel coronavirus associated with severe acute respiratory syndrome (SARS-CoV) were constructed based on the crystal structures of Mpro from transmissible gastroenteritis coronavirus (TGEV) (MproT) and human coronavirus HcoV-229E (MproH), respectively. Both MproST and MproSH exhibit similar folds as their respective template proteins. These homology models reveal three distinct functional domains as well as an intervening loop connecting domains II and III as found in both template proteins. A catalytic cleft containing the substrate binding sites S1 and S2 between domains I and II are also observed. S2 undergoes more significant structural fluctuation than S1 during the 400 ps molecular dynamics simulations because it is located at the open mouth of the catalytic cleft, while S1 is situated in the very bottom of this cleft. The thermal unfolding of these proteins begins at domain III, where the structure is least conserved among these proteins. Mpro may still maintain its proteolytic activity while it is partially unfolded. The electrostatic interaction between Arg40 and Asp186 plays an important role in maintaining the structural integrity of both S1 and S2.

Cytokine release from osteoblasts in response to ultrasound stimulation

Bone is a dynamic tissue with a well-balanced homeostasis preserved by both formation and resorption of bone. Normal turnover of bone, however, can be upset by either increased osteoclast activity or decreased osteoblast function; either mechanism alone or both may result in a net loss of bone. Both osteoclasts and osteoblasts could be stimulated by mechanical stimulation in vitro, and it is assumed that this process may occur in vivo as well. In this experiment, we investigated this hypothesis by examining the effects of ultrasound stimulation on osteoblast growth and cytokine release. With this model, we explored the mechanism of low-intensity pulsed ultrasound on osteoblasts growth and upregulation of osteoclasts formation and function by cytokine release. The results showed that specific pulsed ultrasound exposure could enhance osteoblasts population together with increase in TGFbeta1 secretion and decrease in concentration of IL-6 and TNFalpha in the culture medium. Although, animal studies and clinical trial are needed to understand the real process in the whole body, ultrasound stimulation might be a good method for prevention of bone loss due to osteoporosis.

Outpatient weekly neoadjuvant chemotherapy followed by radiotherapy for advanced nasopharyngeal carcinoma: high complete response and low toxicity rates

Nasopharyngeal carcinoma (NPC) is a radiosensitive and chemosensitive tumour. The aim of this prospective study is to evaluate the toxicity and efficacy of an outpatient weekly neoadjuvant chemotherapy (NeoCT) plus radiotherapy for advanced NPC. From November 1998 to August 2001, 90 NPC patients meeting the following criteria were treated: (1) neck node >6 cm; (2) supraclavicular node metastasis; (3) skull base destruction/intracranial invasion plus multiple nodes metastasis; (4) multiple neck nodes metastasis with one of nodal size >4 cm; or (5) elevated serum LDH level. The NeoCT consists of cisplatin 60 mg m(-2), alternating with 5-fluorouracil 2500 mg m(-2) plus leucovorin 250 mg m(-2) (P-FL) by an outpatient weekly schedule for a total of 10 weeks. Local radiotherapy > or =70 Gy by conventional fractionation was delivered within 1 week after NeoCT. Patient compliance was rather good. Grade 3-4 toxicity of NeoCT included leucopaenia (7.8%), anaemia (18.9%), thrombocytopaenia (3.3%), nausea/vomiting (4.4%), and weight loss (1.1%). Response evaluated after NeoCT showed 73.3% complete response (CR) rate of primary tumour, 71.1% CR rate of neck nodes, and an overall CR rate of 57.8%. In all, 88 out of 90 patients received rebiopsy of primary tumour and 55 patients (62.5%) revealed pathological CR. After a median follow-up time of 24 months, one persistent disease and 18 relapses were noted. The 2-year nasopharynx disease-free, neck disease-free, distant disease-free, overall, and progression-free survival rates are 98.9, 95.9, 80.0, 92.1, and 77.5%, respectively. Preliminary data of the current study show that P-FL NeoCT plus radiotherapy is a low-toxic regimen with promising results on very advanced NPC patients and merits to be investigated in phase III trials.

Yield and nutritive quality of sericea lespedeza (Lespedeza cuneata) and little bluestem (Schizachyrium scoparium) exposed to ground-level ozone

Sericea lespedeza (Lespedeza cuneata cv. Interstate 76) and little bluestem (Schizachyrium scoparium cv. Aldous) were raised from seed in a glasshouse, transplanted into 5.7-l pots and placed into open-top chambers (OTC) on 6 June 1999. Following a 7-day adjustment period, each of six OTCs (duplicate OTCs per treatment) was ventilated with either air that had been carbon-filtered (CF) to remove ambient ozone (O3); non-filtered (NF), representative of ambient air; or enriched to twice-ambient O3 concentration (2X). Primary-growth forage was harvested on days 7, 32, 46, 59 and 72 following the start of fumigation, and regrowth forage from the first primary-growth harvest was harvested on days 36, 54 and 72 following the start of fumigation. Dry matter (DM) yield of either forage species did not differ among treatments except in the final regrowth period when yield of sericea lespedeza was greater for the NF than 2X O3 treatment. In vitro DM digestibility (IVDMD) and concentrations of crude protein (CP), soluble phenolics (SP) and condensed tannins (CT) in primary-growth sericea lespedeza did not differ between treatments, but NF primary-growth forage had higher concentration of protein-precipitating tannins (PPT) than did 2X primary-growth forage. Concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were higher in NF and 2X than in CF primary-growth sericea lespedeza. Similarly, concentrations of NDF and ADL were higher, and IVDMD was lower for NF and 2X than for CF regrowth sericea lespedeza. Concentrations of ADF and ADL were lower, whereas IVDMD, in vitro NDF digestibility (IVNDFD) and concentrations of CP and SP were greater, in CF than in NF and 2X primary-growth little bluestem. Percentages IVDMD and IVNDFD and concentrations of CP and SP in NF primary-growth little bluestem were greater than those in forage exposed to 2X O3 treatment. No significant differences were observed among treatments in percentages IVDMD and IVNDFD, or concentrations of cell wall constituents or SP in little bluestem regrowth. Nutritive quality of little bluestem was decreased by < 2%, and that of sericea lespedeza by approximately 7% as a result of increased concentrations of cell wall constituents and decreased in vitro digestibility of NF and 2X compared with CF forages. Results indicate that existing and projected O3 levels can drive alterations in forage quality of select warm-season forages sufficient to have nutritional and economic implications for their utilization by ruminant herbivores.

Studies of a novel human thrombomodulin immobilized substrate: surface characterization and anticoagulation activity evaluation

Immobilization of the anticoagulative or antithrombogenic biomolecule has been considered as one of the important methods to improve the blood compatibility of artificial biomaterials. In this study, a novel immobilization reaction scheme was utilized to incorporate the human thrombomodulin, an endothelial cell associated glycoprotein, onto the cover glass surface with an aim to develop an anticoagulative substrate. Trichlorotriazine and amino-terminated silane were employed as the coupling agents, while the polyethylene glycol with a molecular weight of 1500 was used as the spacer in this reaction scheme. Protein C activation assay indicated the immobilized human thrombomodulin still has this coenzymatic activity but is lower, possibly due to the conformation variation by the coupling agents. In vitro platelet adhesion assay has demonstrated the surface with immobilized human thrombomodulin is much less platelet-activating than others. Therefore, the novel reaction scheme proposed here is very promising for future development of an anticoagulative silicon or cover glass substrate (e.g. implantable sensor or biochip) by the immobilization of antithrombogenic protein, such as the human thrombomodulin in this study.

Surface characterization and platelet compatibility evaluation of surface-sulfonated chitosan membrane

The effect of various sulfonated derivatives of chitosan on platelet activation and blood coagulation was examined. The surface properties of artificial biomaterials have been thought as the key factors which mediate the interactions between the biological environment and biomaterial itself. In this study, the sulfonation was directly performed on the chitosan membrane surface. The chitosan membrane was surface-sulfonated by reactions with sulfur-pyridine trioxide complex (SO3/pyridine) in H2O solution and N,N-sulfur-dimethylformamide trioxide complex (SO3/DMF) in DMF. Blood compatibility was evaluated by an in vitro platelet adhesion assay. The surface reaction of SO3/pyridine in aqueous acid medium yields N,O-sulfated chitosan with cationic NH3+ groups. After neutralization, this surface has been shown to induce a low degree of platelet adhesion and activation. When the surface-sulfonation is performed in an aqueous alkaline medium, although the degree of sulfonation is lower than the samples above, the N-sulfated chitosan significantly reduced the adhesion and activation of platelets. For the acidic SO3/DMF reaction system, N,O-sulfated chitosan was obtained with a high extent of sulfonation and cationic NH3+ groups. On this surface fully spread platelets and some platelet aggregates were found instead. This may be attributed to the ionic interactions between the platelets membrane surface and the cationic groups on the modified chitosan membrane.

Pressure overload induces heterologous expression of the atrial natriuretic factor (ANF) gene

Several investigations have demonstrated the regional heterogeneity of myocardial phenotype, and hypertrophy may also induce regionally disparate changes. We have utilized the direct DNA injection technique to study regional variations in overload-induced ANF expression. Pressure overload was induced by stenosis of the ascending aorta in canines. ANF promoter reporters were injected into the left ventricle; in different regions including the base, the midwall region, and the apex. Injections were made at different depths to include the epicardial and endocardial layers. The animals were sacrificed 7 days following surgery and the left ventricle harvested for tissue analysis. Under normotensive conditions, ANF reporter expression was similar throughout the heart. PO increased ANF expression and the increases were greater in the endocardium than in the epicardium. PO also significantly increased expression in the midwall and base regions, but not in the apex. It is unknown from these experiments, whether the greater increases in midwall expression are a function of greater wall stress, metabolic demand, or phenotypic differences in the midwall myocytes. These findings do indicate that regional differences in overload-induced changes in gene expression are evident and may be functionally important in determining myocardial response to increased functional demand.

Up-regulation of Fas ligand expression by human cytomegalovirus immediate-early gene product 2: a novel mechanism in cytomegalovirus-induced apoptosis in human retina

Human CMV (HCMV) is an important pathogen that causes widespread diseases in immunocompromised individuals. Among the opportunistic HCMV infections, HCMV retinitis is most common in transplant recipients and AIDS patients. It often leads to blindness if left untreated. The question as to how HCMV infection causes retinal pathogenesis remains unresolved. Here, we report that viral immediate-early gene product 2 (IE2), but not IE1, up-regulates the Fas ligand (FasL) expression in HCMV-infected human retinal pigment epithelium cells. Increased secretion of FasL from virally infected cells into cultured medium was observed upon HCMV infection. The capability of such cell-free medium to induce apoptosis of Fas (CD95)-expressing Jurkat cells further implies that Fas-FasL interaction might mediate cell death in the lesion of HCMV retinitis. To support this idea, we observed augmented soluble FasL levels in vitreous from AIDS patients with HCMV retinitis as compared with that from AIDS patients without HCMV infection. In addition, by in situ hybridization and immunohistochemistry, we detected enhanced signals of FasL, the existence of viral IE Ags and apoptotic cells at the same sites in the lesion of HCMV-infected retina. These results strongly suggest that IE2 induction of FasL expression in human retina might be an important event that takes place in the early stage of infection and finally leads to visual loss in individuals affiliated with HCMV retinitis.