Solid-State Carbon-Doped GaN Schottky Diodes by Controlling Dissociation of the Graphene Interlayer with a Sputtered AlN Capping Layer

Carbon-doped GaN (GaN:C) Schottky diodes are prepared by controlling the destruction status of the graphene interlayer (GI) on the substrate. The GI without a sputtered AlN capping layer (CL) was destroyed because of ammonia precursor etching behavior in a high-temperature epitaxy. The damaged GI, like nanographite as a solid-state carbon doping source, incorporated the epitaxial growth of the GaN layer. The secondary ion mass spectroscopy depth profile indicated that the carbon content in the GaN layer can be tuned further by optimizing the sputtering temperature of AlN CL because of the better capping ability of high crystalline quality AlN CL on GI being achieved at higher temperature. The edge-type threading dislocation density and carbon concentration of the GaN:C layer with an embedded 550 °C-grown AlN CL on a GI substrate can be significantly reduced to 2.28 × 10⁹ cm^-2 and ∼2.88 × 10¹⁸ cm^-3, respectively. Thus, a Ni-based Schottky diode with an ideality factor of 1.5 and a barrier height of 0.72 eV was realized on GaN:C. The series resistance increased from 28 kΩ at 303 K to 113 kΩ at 473 K, while the positive temperature coefficient (PTC) of series resistance was ascribed to the carbon doping that induced the compensation effect and lattice scattering effect. The decrease of the donor concentration was confirmed by temperature-dependent capacitance-voltage (C-V-T) measurement. The PTC characteristic of GaN:C Schottky diodes created by dissociating the GI as a carbon doping source should allow for the future use of high-voltage Schottky diodes in parallel, especially in high-temperature environments.

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.

Preparation and Characteristics of MAPbBr₃ Perovskite Quantum Dots on NiOx Film and Application for High Transparent Solar Cells

In this work, a MAPbBr₃ quantum dot (QD-MAPbBr₃) layer was prepared by a simple and rapid method. Octylammonium bromide (OABr) gives the MAPbBr₃ better exciton binding energy, good surface morphology, and stability. To form a nanocrystalline thin film on indium tin oxide (ITO) glass, the QD-MAPbBr₃ film was coated by a spin-coating method in a nitrogen-filled glove box and the NiO_x film was used as an adhesive layer and hole transport layer. The highest transmittance of MAPbBr₃ on NiO_x/ITO glass was around 75% at 700 nm. This study also reported a high transparent and perovskite bulk-free ITO/NiO_x/QD-MAPbBr₃/C₆₀/Ag solar cell where the NiO_x, QD-MAPbBr₃, and C₆₀ were used as a hole transport layer, active layer, and electron transport layer, respectively.

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.

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.

Osthole inhibits insulin-like growth factor-1-induced epithelial to mesenchymal transition via the inhibition of PI3K/Akt signaling pathway in human brain cancer cells

Glioblastoma multiforme (GBM) is one of the most lethal types of tumors and highly metastatic and invasive. The epithelial-to-mesenchymal transition (EMT) is the crucial step for cancer cells to initiate the metastasis and could be induced by many growth factors. In this study, we found that GBM8401 cells were converted to fibroblastic phenotype and the space between the cells became expanded in response to insulin-like growth factor-1 (IGF-1) treatment. Epithelial markers were downregulated and mesenchymal markers were upregulated simultaneously after IGF-1 treatment. Our results illustrate that IGF-1 was able to induce EMT in GBM8401 cells. Osthole would reverse IGF-1-induced morphological changes, upregulated the expression of epithelial markers, and downregulated the expression of mesenchymal markers. Moreover, wound-healing assay also showed that osthole could inhibit IGF-1-induced migration of GBM8401 cells. By using dual-luciferase reporter assay and real-time PCR, we demonstrated that osthole inhibited IGF-1-induced EMT at the transcriptional level. Our study found that osthole decreased the phosphorylation of Akt and GSK3β and recovered the GSK3β bioactivity in inhibiting EMT transcription factor Snail and Twist expression. These results showed that osthole inhibited IGF-1-induced EMT by blocking PI3K/Akt pathway. We hope that osthole can be used in anticancer therapy and be a new therapeutic medicine for GBM in the future.

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.

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.

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.

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.

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.

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.

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.

Effect of pravastatin-to-simvastatin conversion on low-density-lipoprotein cholesterol

The effects of a pravastatin-to-simvastatin conversion program on low-density-lipoprotein (LDL) cholesterol levels were studied. Patients receiving pravastatin at a Veterans Affairs medical center were switched to simvastatin beginning in 1997. The dosage of simvastatin was based on the additional percent reduction in LDL cholesterol needed to achieve the goal specified by the National Cholesterol Education Program. The primary endpoint was the change in the percentage of patients meeting their LDL cholesterol goal at baseline and follow-up. Changes in lipid indices, the relative risk (RR) of coronary heart disease (CHD), and program costs were also evaluated. A total of 1032 patients completed the program. The mean +/- S.D. daily doses of pravastatin and simvastatin were 25.2 +/- 11.3 and 22.7 +/- 13.3 mg, respectively. Median baseline and follow-up LDL cholesterol concentrations were 116 and 99 mg/dL, respectively (p < 0.001). Overall, 44% of the patients met their LDL cholesterol goal while taking pravastatin, compared with 69% after conversion to simvastatin (p < 0.001). The predicted mean RR of a future CHD event (based on changes in serum lipids) was 0.87 (95% confidence interval, 0.83-0.91) four years after conversion. The total cost of the program was $40,644 in the first year, and there was a net saving thereafter. Therapeutic interchange between pravastatin and simvastatin increased the number of patients meeting their LDL cholesterol goal.

Surface characterization and platelet adhesion studies on polyethylene surface with hirudin immobilization

Hirudin, a protein composed of 65 or 66 amino acid, is a newly risen anticoagulant agent and has been considered as the most potent thrombin inhibitor. Hirudin can block the active site of thrombin by means of its carboxylic acid reaction with the active regime of thrombin, and becomes a tightly bound complex, and thus controls the formation of thrombus. Hirudin was covalently immobilized onto the water-soluble carbodiimide preactivated and chromic acid oxidized PE surface. Surface chemistry analysis indicated that a certain amount of carboxylic acid groups was generated on the polyethylene surface after oxidation with chromic acid solution. The amount of carboxylic acid functional group increased with the oxidation time. In addition, polyethylene surface was etched by chromic acid solution, and a rougher surface was created. The morphology of oxidized polyethylene surface was similar to each other among the samples with oxidation time from 1 to 8 min. ESCA results indicated the number of hirudin molecules immobilized was constant at the reaction time studied. In vitro platelet adhesion assay indicated the number of adhered platelets on the oxidized polyethylene surface increased significantly after oxidation. In contrast, surface with hirudin immobilization showed a reduction in adhered platelet density than the chromic acid oxidized counterpart due to the decrease of platelet-activating capability by the hirudin-thrombin complex and the differences in the adsorbed protein composition.

Evaluation of early-stage Parkinson's disease with 99mTc-TRODAT-1 imaging

Parkinson's disease is a progressive neurodegenerative disorder characterized by a selective loss of dopamine in the striatum. Problems remain in the accurate diagnosis of Parkinson's disease. A 99mTc-labeled tropane derivative that binds to dopamine transporter with high selectivity is [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)] (TRODAT-1). The purpose of this study was to investigate the potential usefulness of 99mTc-TRODAT-1 imaging in the evaluation of patients with early-stage Parkinson's disease.

METHODS

Thirty-four patients with early-stage idiopathic Parkinson's disease were recruited. For all patients, the Parkinson's disease was stage 2 or less as assessed by the Hoehn and Yahr scale. Seventeen age-matched healthy volunteers (8 men, 9 women) served as controls. 99mTc-TRODAT-1 was prepared from a lyophilized kit. Brain SPECT imaging was performed between 165 and 195 min after injection, using a double-head camera equipped with fanbeam collimators. Specific uptake in the striatum and its subregions, including the putamen and caudate nucleus, was calculated and compared with that of the other sides and of healthy volunteers.

RESULTS

A continuous reduction in specific striatal uptake of 99mTc-TRODAT-1 with increasing disease severity was found in Parkinson's disease patients (control vs. stage I vs. stage II, 1.98 vs. 1.62 vs. 1.22, respectively, P < 0.01). The changes were magnified by measurement of specific putaminal uptake (control vs. stage I vs. stage II, 1.81 vs. 1.27 vs. 0.94, respectively, P < 0.01). The mean values of specific putaminal uptake contralateral to the more affected limbs were significantly decreased compared with the ipsilateral sides in both stage I and stage II groups (1.02 vs. 1.49 for stage I and 0.73 vs. 1.14 for stage II, P < 0.01). Moreover, a significant loss of putaminal uptake ipsilateral to the symptoms was found in the stage I group compared with the healthy volunteers (1.49 vs. 1.81, P < 0.01). The difference became greater when the posterior putaminal uptakes were compared. No remarkable adverse reactions were found in either healthy volunteers or Parkinson's disease patients during or after imaging.

CONCLUSION

For clinical practice, 99mTc-TRODAT-1 may serve as a useful imaging agent for the early detection of Parkinson's disease.

Non steroidal anti-inflammatory drug-based pain control for minimally invasive direct coronary artery bypass surgery

Minimally invasive direct coronary artery bypass (MIDCAB) surgery has become an attractive alternative technique to treat coronary artery insufficiency. Changes in surgical and anesthesia techniques have led to reduced pulmonary morbidity associated with the operation. Early extubation is typically expected. However, postoperative pain management becomes even more important with early extubation. We describe our technique of a NSAID-based protocol with indomethicin and Torodal that has been safe and effective in over 175 patients following MIDCAB.

Stress-inducible transcription factor CHOP/gadd153 induces apoptosis in mammalian cells via p38 kinase-dependent and -independent mechanisms

CHOP/gadd153 is a transcription factor induced by cellular stresses such as UV light, genotoxic agents, and protein misfolding in the endoplasmic reticulum. The fact that these stresses induce CHOP expression, and at the same time cause cellular apoptosis, suggests that CHOP may be directly involved in apoptosis. However, evidence has been circumstantial. Here, we show that CHOP can directly induce apoptosis. A GFP-tagged CHOP vector, ectopically overexpressed in several cell types (3T3 fibroblasts, keratinocytes, and HeLa cells), caused apoptosis as defined by morphology, DNA fragmentation, and FACS analysis. Apoptosis was quantified using a rapid fluorescence assay that measures the signal from cells collected in culture supernatants. The apoptosis-modulating effects of p38 kinase, previously shown to phosphorylate CHOP, were also examined. Simultaneous overexpression of CHOP and p38 significantly augmented apoptosis. However, although p38 kinase clearly modulated the activity of full-length CHOP, it was not absolutely required. Deletion mapping experiments showed that the bZIP region of CHOP stimulates apoptosis to nearly the same extent as wild-type CHOP. Thus, while the amino-terminal region of CHOP serves an important modulatory role (i.e., regulation by p38), the underlying apoptosis-inducing activity of CHOP resides within the bZIP region of the molecule.

Surface characterization and platelet adhesion studies of self-assembled monolayer with phosphonate ester and phosphonic acid functionalities

Because of its well-defined surface configuration and creative chemical structure, an alkanethiol self-assembled monolayer (SAM) on gold is a model surface for a blood compatibility investigation. In this study two laboratory-synthesized long-chain alkanethiols, HS(CH(2))(10)PO(3)-(C(2)H(5))(2) and HS(CH(2))(10)PO(3)H(2), were employed for the direct preparation of SAMs with nonionic and ionic functional groups. Various instrumental analyses confirmed the high purity of the phosphonate ester and phosphonic acid terminated alkanethiols. The surface characterization results showed the -PO(3)H(2) terminated SAM was more hydrophilic than the -PO(3)(C(2)H(5))(2) one. Higher hysteresis values for the -PO(3)(C(2)H(5))(2) and -PO(3)H(2) terminated SAMs were noted, which were possibly due to the steric hindrance of the bulky terminal groups. In addition, the O(2) plasma + EtOH-rinse pretreated Au sample was hydrophilic because of the residual gold oxide on the surface. This finding was supported by electron spectroscopy for chemical analysis (ESCA) as well. The ESCA analysis also indicated bulky and polar terminal groups [-PO(3)(C(2)H(5))(2) and -PO(3)H(2)] were situated in the outermost layer of its monolayer. The platelet reactivity on the SAM with the nonionic group -PO(3)(C(2)H(5))(2) was less than those of the ionic terminated SAMs -COOH and -PO(3)H(2). The O(2) plasma + EtOH-rinse pretreated gold substrate exhibited the least platelet-activating surface among the different pretreated Au substrates studied.

Detection of Epstein-Barr virus DNA in the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival

PURPOSE

Nasopharyngeal carcinoma (NPC) has been proved to be an Epstein-Barr virus (EBV)-associated cancer. By use of nested polymerase chain reactions (PCRs), we examined whether the presence of EBV DNA in the peripheral-blood cells (PBC) can serve as a prognostic indicator for NPC.

PATIENTS AND METHODS

Peripheral blood from 124 patients with NPC who had no evidence of distant metastasis and 114 healthy volunteers with serologically positive findings for EBV infection was collected prospectively. Plasma and erythrocytes were separated. DNA was extracted from PBCs and analyzed by a nested PCR using primers specific to Epstein-Barr virus nuclear antigen 1 (EBNA-1). All patients were treated by radiotherapy with or without chemotherapy. Clinical parameters and status of EBNA-1 in PBCs were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards model.

RESULTS

Positive rates of EBNA-1 DNA in PBCs of NPC patients and healthy volunteers are 71% and 14%, respectively (P =.001). No significant difference was observed with regard to the clinical characteristics of patients who were EBNA-1-positive (n = 88) and those who were EBNA-1-negative (n = 36). After a median follow-up period of 38 months (range, 24 to 56 months), 29 of 88 EBNA-1-positive patients and only one of 36 EBNA-1-negative patients developed distant metastases (P =.00015). Kaplan-Meier estimates of overall survival (P =.0010), metastasis-free survival (P =.0004), and progression-free survival (P =.0004) were significantly lower for the patients in the EBNA-1-positive group than for those in the EBNA-1-negative group. Multivariate Cox analysis confirmed the same results.

CONCLUSION

The presence of EBNA-1 DNA in PBCs is a novel, important risk factor for patients with NPC that indicates a significantly higher risk of developing distant metastasis as well as a lower survival rate.

Efficacy of cefepime versus ceftazidime in the treatment of adult pneumonia

Effective empiric treatment of pneumonia requires antibiotic coverage against gram-negative and gram-positive pathogens, including drug-resistant isolates. This study evaluated the efficacy of cefepime treatment in 20 patients with community-acquired pneumonia (CAP) and 21 patients with hospital-acquired pneumonia (HAP), and ceftazidime treatment in 20 patients with HAP. The mean age of patients was over 70 years. More than half of the patients had multiple lobe involvement. There was no significant difference in the severity of illness according to the acute physiology, age, chronic health evaluation (APACHE) III score between the HAP-cefepime and HAP-ceftazidime group. The most common bacteria isolated from sputum of patients with CAP were Streptococcus pneumoniae (n = 7), Klebsiella pneumoniae (n = 4), and Pseudomonas aeruginosa (n = 2). In patients with HAP, P. aeruginosa (n = 13), Acinetobacter baumannii (n = 11), Serratia marcescens (n = 6), K. pneumoniae (n = 5), Stenotrophomonas maltophilia (n = 5), Enterobacter cloacae (n = 3), Citrobacter spp. (n = 2), and Escherichia coli (n = 2) were isolated. The cure rates were 95%, 76%, and 60% in the CAP-cefepime group, the HAP-cefepime group, and the HAP-ceftazidime group, respectively. The increased rates of antimicrobial resistance commonly found among isolates causing CAP and HAP indicate that extended-spectrum antimicrobial agents, such as cefepime, would be more appropriate therapeutic agents.

The Role of Video-Assisted Thoracic Surgery for Pulmonary Metastasectomy

Management of isolated metastatic deposits to the lungs and the role of surgical resection, specifically video-assisted thoracic surgery (VATS) techniques, have been controversial. The inability to perform a detailed bimanual palpation of the lung for occult lesions has been considered an inherent weakness in this approach. We have performed VATS resection for 205 patients with pulmonary metastatic disease and potentially curative VATS resec-tion for 119 patients. VATS resection was successfully performed for all VATS diagnostic and therapeutic patients, with no perioperative deaths. Longitudinal follow-up demonstrated a mean survival of 20 months in the diagnostic group and 32 months in the therapeutic group. In the VATS therapeutic group, 44 (37%) patients remain free of disease at a mean follow-up of 37 months. Of the 69 recurrences, 6% were local, 25% were regional, and 67% were distant. In this review, the present role of VATS pulmonary metastasectomy will be examined.

A 915-MHz antenna for microwave thermal ablation treatment: physical design, computer modeling and experimental measurement

A 915-MHz antenna design that produces specific absorption rate distributions with preferential power deposition in tissues surrounding and including the distal end of the catheter antenna is described. The design features minimal reflected microwave current from the antenna flowing up the transmission line. This cap-choke antenna consists of an annular cap and a coaxial choke which matches the antenna to the coaxial transmission line. The design minimizes heating of the coaxial cable and its performance is not affected by the depth of insertion of the antenna into tissue. The paper provides a comparison of results obtained from computer modeling and experimental measurements made in tissue equivalent phantom materials. There is excellent agreement between numerical modeling and experimental measurement. The cap-choke, matched-dipole type antenna is suitable for intracavitary microwave thermal ablation therapy.

Deficiency of the specific granule proteins, R-binder/transcobalamin I and lactoferrin, in plasma and saliva: a new disorder

The mechanisms of hereditary deficiency of R binder, which originates in neutrophils and exocrine gland epithelium, are unknown and may be multiple. This led us to examine if defective R binder synthesis also involves proteins that colocalize with it in neutrophil-specific granules and exocrine epithelial cells and may be under common regulatory control. Stored plasma and saliva samples from five unrelated R binder-deficient patients and control subjects were assayed for R binder, lactoferrin, cationic antimicrobial protein-18, neutrophil gelatinase-associated lipocalin, gelatinase, lysozyme, and myeloperoxidase. One patient, patient A, had lactoferrin levels below the limits of detection in both plasma and saliva in addition to his R binder deficiency. Although his deficiency involved lactoferrin as well, he had no history of predisposition to infection. PCR amplification of his R binder gene promoter region and the beginning of the first exon revealed no DNA abnormalities. His son and the son of his equally deficient brother, both presumptive heterozygotes, had mild deficiency of both R binder and lactoferrin. The results show that R binder deficiency exists in at least two forms. One, presumably the less common of the two forms, is the new hereditary entity described here, which is characterized by deficiency of more than one specific granule protein in both plasma and saliva. Despite this more widely distributed absence of the proteins than is found in congenital specific granule deficiency, infection posed no clinical problem in the affected patient.

In vitro and in vivo studies for modified ethyl cyanoacrylate regimens for sclerotherapy

Cyanoacrylates have known for their ability to polymerize rapidly in the presence of traces of weakly basic moieties such as water. The tissue adhesive, Histoacryl(R) (N-butyl 2-cyanoacrylate), has been reported to control bleeding through endoscopic sclerotherapy. But the commercially available Histoacryl(R) is expensive, and it has the problem like other cyanoacrylates that the glue tends to flow/run away from the point of application, which is inherent to the low viscosity, making precise application difficult. In this study, ethyl cyanoacrylate (ECA), the main constituent of "super glue," was employed instead of Histoacryl(R) due to its lower cost. The aim of the research is to modify the compositions of ECA regimen and evaluate its feasibility for sclerosant application through both in vitro flow circuit model and in vivo animal tests. It was noted that the difference in the relative hardening rate between the in vitro Hepes-Tyrodes buffer flowing model and the in vivo rat model for the ECA and Histoacryl(R) was related to the existence of the blood protein, such as albumin, in the physiological milieu. It was also noticed that the ECA setting rate was greatly increased either in Hepes-Tyrodes buffer or in blood (to a comparable rate as Histoacryl(R) in vivo) by adding a few doses of caffeine, which acts as a polymerization initiator. This would lead to far better injection precision during sclerotherapy. Furthermore, in vivo histological examination for the occluded lumen of the rat's inferior vena cava and a clinical piglet portal vein occlusion experiment have suggested this new sclerosant regimen, caffeine/ECA, is of great promise in endoscopic sclerotherapy.

Surface characterization and platelet adhesion studies on fluorocarbons prepared by plasma-induced graft polymerization

It is believed that the interactions between the biological environment and biomaterial surface are the key factors influencing its biocompatibility. Therefore, plasma processing, which can vary the surface properties without altering the bulk properties, has been considered as one of the important techniques for improving a materials' biocompatibility. In this investigation, plasma-induced grafting polymerization of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE), instead of direct plasma polymerization, was attempted with an aim to improve the substrate blood compatibility. Contact angle measurement indicated both fluorocarbon-grafted Pdyethylenes (PEs) are hydrophobic. Due to the additional fluorine and chlorine atoms on the CTFE chain, the PCTFE-grafted PE exhibited a higher hydrophobicity than the PVDF-grafted one. ESCA analysis has revealed that these two plasma-induced fluorocarbon deposits contain almost no CFx (x > 2) binding on the surface layer, indicating the grafting polymerization mainly follows the free radical mechanism instead of the molecule-highly-fragmented reaction steps commonly seen in the direct plasma polymerization treatment. In addition, ATR-FTIR has shown the surface chemical configuration of these PVDF- and PCTFE-grafted PEs to be very similar to those of the bulk samples of PVDF and PCTFE. The surface roughness decreased after oxygen plasma treatment and was further reduced by VDF and CTFE grafting polymerization. In vitro platelet adhesion testing indicated these two fluorocarbon grafted PEs are less platelet-activating than the nontreated PE control and oxygen plasma activated one.

Functional mutation in the promoter region of thrombomodulin gene in relation to carotid atherosclerosis

Thrombomodulin is an important endothelial anticoagulant protein that decreases thrombin activity and activates protein C. Our recent study has shown that the G-33A promoter mutation of thrombomodulin gene is associated with coronary artery disease. This study was conducted to determine whether the G-33A mutation in the promoter region of thrombomodulin gene is a genetic risk factor for ischemic stroke or carotid atherosclerosis. The functional significance of this mutation was also evaluated. We recruited 333 patients (mean age 64 years, 59% male) with ischemic stroke and 257 age- and sex-matched controls. In all study participants, carotid atherosclerosis was assessed by Duplex scanning, and thrombomodulin G-33A promoter mutation was detected by single-strand conformation polymorphism. Luciferase reporter gene assay was used to assess the influence of this mutation on thrombomodulin promoter activity. There was no significant difference in the thrombomodulin G-33A mutation frequency (GA+AA genotypes) between the stroke and the control groups (18.3 vs. 24. 1%, P=0.105). The G-33A mutation frequency was also similar between the study participants with and without carotid atherosclerosis (22.2 vs. 19.8%, P=0.550). When only younger subjects (age </=60 years) were included in the analysis, however, we found the mutation occurred more frequently in participants with carotid atherosclerosis (33.3 vs. 17.3%, odds ratio [OR]=2.38, 95% confidence interval [CI]=1.16-4.90, P=0.027). Multiple logistic regression analyses showed that only diabetes mellitus (OR=3.11, 95% CI=1.33-7.30, P=0.009) and G-33A mutation (OR=2.46, 95% CI=1.14-5.29, P=0.021) were associated independently with carotid atherosclerosis in younger subjects. As assessed by luciferase reporter gene assays, the contructs bearing the G-33A mutation showed a significant decrease (36+/-12%) in transcriptional activity in comparison with the wild type constructs. Our findings suggest that G-33A mutation reduces the thrombomodulin promoter activity and is associated with carotid atherosclerosis in younger subjects.

Excess mortality due to pneumonia or influenza during influenza seasons among persons with acquired immunodeficiency syndrome

BACKGROUND

Anecdotal reports suggest that influenza-related morbidity may be high among persons with acquired immunodeficiency syndrome (AIDS), but little information is available concerning the population-level impact of influenza on mortality in persons with AIDS.

METHODS

Using the Multiple Cause-of-Death data files, which contain information on all deaths occurring in the United States each year, we calculated the numbers of excess deaths and rates of excess death due to pneumonia or influenza among persons with AIDS aged 13 years and older during the influenza seasons 1991-1992 through 1993-1994. For comparison, numbers of excess deaths and excess death rates were also calculated for several other groups including the general US population aged 13 years and older and the general US population aged 65 years and older.

RESULTS

During the 1991-1992, 1992-1993, and 1993-1994 influenza seasons, there were 261, 254, and 191 excess deaths due to pneumonia or influenza in persons with AIDS and excess death rates of 19.74, 15.38, and 10.17 deaths per 10 000 persons, respectively, compared with a summer baseline period. For the same seasons, we observed excess death rates of 1.40, 1.62, and 1.48 for the general US population aged 13 years and older and 8.10, 9.28, and 8.54 for the general US population aged 65 years and older. Thus, persons with AIDS had excess death rates substantially higher than the general US population and similar to, if not somewhat higher than, the general US population aged 65 years and older, a group that is already targeted for annual vaccination. The findings were similar when we compared the preinfluenza season with the influenza season.

CONCLUSIONS

Persons with AIDS have significant excess mortality due to pneumonia or influenza during influenza seasons and should be considered a high-risk group that is targeted for the prevention of influenza.

The external granule layer of the developing chick cerebellum generates granule cells and cells of the isthmus and rostral hindbrain

The external granule layer (EGL) on the dorsal surface of the developing cerebellum consists of neural progenitors originating from the rostral rhombic lip (RRL). The RRL and the EGL were thought to give rise exclusively to the granule neurons of the cerebellum (Alder et al., 1996). To study the fate of individual RRL cells, we used a retroviral library to mark clones in the chick embryo at Hamberger-Hamilton stages 10-12. RRL clones comprised the EGL and cerebellar granule cells, as expected. Surprisingly, however, as many as 50% of the RRL clones also contained cells ventral to the cerebellum proper. Ventral derivatives were found in clones with a medial origin, as well as in those with a lateral origin along the RRL. Some of the ventral progeny appeared to be in the process of migration, whereas others appeared to be differentiating neurons in the isthmus and the rostral hindbrain region, including the locus coeruleus (LC) and pontine reticular formation. Furthermore, the Phox2a marker of LC precursors was detected in the EGL within the anterior aspect of the cerebellum. A stream of cells originating in the EGL and expressing Phox2a was observed to terminate ventrally in the LC. These data demonstrate that single RRL progenitor cells are not restricted to producing only cerebellar granule cells; they produce both cerebellar granule cells and ventral derivatives, some of which become hindbrain neurons. They also suggest that some progeny of the EGL escape the cerebellum via the anterior aspect of the cerebellar peduncles, to contribute to the generation of ventral structures such as the LC.