Controlled release of an antibiotic, gentamicin sulphate, from gravity spun polycaprolactone fibers

The antibiotic, gentamicin sulphate (GS), was incorporated in gravity-spun polycaprolactone (PCL) fibers by spinning from particulate suspensions of the drug in PCL solution to produce a controlled delivery system. The production rate of GS-loaded PCL fibers was confined to the range 1-1.5 m/min and the fiber diameter to 170-220 microm. The kinetics of drug release could be adjusted by varying the GS loading of the fibers and the suspension preparation conditions. Gradual release of approximately 80% of the initial GS content was measured in phosphate buffered saline at 37 degrees C over 50 days from fibers spun from nonhomogenized suspensions, whereas loss of this amount of antibiotic occurred in less than 10 days from fibers spun from homogenized suspensions. Studies of growth inhibition of Stapyhlococcus epidermidis in culture indicated that GS released after 2 weeks from PCL fibers retained antibacterial activity. This behavior recommends further investigation of PCL fibers for local delivery of antibiotics to combat infection associated with periodontal disease, musculoskeletal injuries, and implantation of fiber-based tissue substitutes such as vascular prostheses.

Discrimination of outer membrane proteins using a K-nearest neighbor method

Identification of outer membrane proteins (OMPs) from genome is an important task. This paper presents a k-nearest neighbor (K-NN) method for discriminating outer membrane proteins (OMPs). The method makes predictions based on a weighted Euclidean distance that is computed from residue composition. The method achieves 89.1% accuracy with 0.668 MCC (Matthews correlation coefficient) in discriminating OMPs and non-OMPs. The performance of the method is improved by including homologous information into the calculation of residue composition. The final method achieves an accuracy of 96.1%, with 0.873 MCC, 87.5% sensitivity, and 98.2% specificity. Comparisons with multiple recently published methods show that the method proposed in this study outperforms the others.

Variants in the 5q31 cytokine gene cluster are associated with psoriasis

A multitiered genetic association study of 25 215 single-nucleotide polymorphisms (SNPs) in three case-control sample sets (1446 patients and 1432 controls) identified three IL13-linked SNPs (rs1800925, rs20541 and rs848) associated with psoriasis. Although the susceptibility effects at these SNPs were modest (joint allelic odds ratios (ORs): 0.76 to 0.78; P(comb): 1.3E-03 to 2.50E-04), the association patterns were consistent across the sample sets, with the minor alleles being protective. Haplotype analyses identified one common, susceptible haplotype CCG (joint allelic OR=1.27; P(comb)=1.88E-04) and a less common, protective haplotype TTT (joint allelic OR=0.74; P(comb)=7.05E-04). In combination with the other known genetic risk factors, HLA-C, IL12B and IL23R, the variants reported here generate an 11-fold psoriasis-risk differential. Residing in the 5q31 cytokine gene cluster, IL13 encodes an important T-cell-derived cytokine that regulates cell-mediated immunity. These results provide the foundation for additional studies required to fully dissect the associations within this cytokine-rich genomic region, as polymorphisms in closely linked candidate genes, such as IRF1, IL5 or IL4, may be driving these results through linkage disequilibrium.

Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

Gene delivery by the hSP-B promoter to lung alveolar type II epithelial cells in LAL-knockout mice through bone marrow mesenchymal stem cells

Tissue damage and inflammation promote bone marrow stem cells (BMSCs) to differentiate into a variety of cell types in residing tissues. BMSCs can stably maintain their plasticity and are an ideal cell population for delivery of therapeutic genes to non-hematopoietic tissues. Using lacZ as a reporter gene, we demonstrated that the lung-specific human surfactant protein B (hSP-B) 1.5-kb promoter is able to deliver the lacZ gene into the lung of lysosomal acid lipase (LAL) gene-knockout (lal-/-) mice by beta-galactosidase staining, flow cytometry and double immunofluorescence staining. Around 10-18% alveolar type II epithelial cells (AT II cells) exhibited positive lacZ gene expression after 8 weeks of BMSC injection in recipient lal-/- mice. The wild-type mice exhibited no expression after the same treatment. BMSCs from hSP-B 1.5-kb lacZ transgenic mice entered and repopulated in lal-/- bone marrow. The study supports a concept that pulmonary inflammation caused by LAL deficiency can trigger BMSC residing in lal-/- bone marrow, migrating into the lung and converting into residential AT II cells. The hSP-B 1.5 kb promoter is an ideal tool to deliver therapeutic genes into AT II cells through BMSCs to cure pulmonary inflammation-triggered diseases.

Proton spin structure in the resonance region

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV<W<1.910 GeV) at an average four momentum transfer of Q2=1.3 GeV2. Using the Jefferson Lab polarized electron beam, a spectrometer, and a polarized solid target, we measured the asymmetries A|| and A(perpendicular) to high precision, and extracted the asymmetries A1 and A2, and the spin structure functions g1 and g2. We found a notably nonzero A(perpendicular), significant contributions from higher-twist effects, and only weak support for polarized quark-hadron duality.

Heterogeneous meshing and biomechanical modeling of human spine

We aim to develop a patient-specific biomechanical model of human spine for the purpose of surgical training and planning. In this paper, we describe the development of a finite-element model of the spine from the VHD Male Data. The finite-element spine model comprises volumetric elements suitable for deformation and other finite-element analysis using ABAQUS. The mesh generation solution accepts segmented radiological slices as input, and outputs three-dimensional (3D) volumetric finite element meshes that are ABAQUS compliant. The proposed mesh generation method first uses a grid plane to divide the contours of the anatomical boundaries and its inclusions into discrete meshes. A grid frame is then built to connect the grid planes between any two adjacent planes using a novel scheme. The meshes produced consist of brick elements in the interior of the contours and with tetrahedral and wedge elements at the boundaries. The nodal points are classified according to their materials and hence, elements can be assigned different properties. The resultant spine model comprises a detailed model of the 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, and S1. Each of the vertebrae and intervertebral disc has between 1200 and 6000 elements, and approximately 1200 elements, respectively. The accuracy of the resultant VHD finite element spine model was good based on visual comparison of volume-rendered images of the original CT data, and has been used in a computational analysis involving needle insertion and static deformation. We also compared the mesh generated using our method against two automatically generated models; one consists of purely tetrahedral elements and the other hexahedral elements.

The effects of all-trans-retinoic acid on cell cycle and alkaline phosphatase activity in pancreatic cancer cells

Pancreatic cancer is one of the tumors with the highest mortality, poorly responding to available chemotherapeutic agents. The objective of this study was to study the anticancer effects of all-trans retinoid acid, a functional form of vitamin A, on pancreatic cancer cells. Human pancreatic cancer MiaPaCa-2 cells were treated with 1, 5, 10, 20, 30, 40 and 50 microM ATRA for 1, 2, 3, 4, 5 or 6 d, respectively. Cell growth was determined by MTT viability assay. The cell cycle distribution and the alkaline phosphatase (ALP) activity were analyzed by flow cytometry and chemical analyzer, respectively. The results show that ATRA significantly inhibited the growth of MiaPaCa-2 cells at 40 and 50 microM. ATRA arrested pancreatic cancer cells at G0/G1 phase. The sub-G1 peak and DNA fragmentation were observed. There were time and dose dependent increases in alkaline phosphatase activity (ALP), an indicator of cell differentiation, upon treatment with ATRA when compared to controls. In conclusion, ATRA has an inhibitory effect on the cell growth of MiaPaCa-2, and its tumor suppressive effect is by means of cell cycle arrest and apoptosis induction.

End-grafted low-molecular-weight PNIPAM does not collapse above the LCST

The interfacial properties of end-grafted temperature-responsive poly(N-isopropylacryamide) (PNIPAM) were quantified by direct force measurements both above and below the lower critical solution temperature (LCST) of 32 degrees C. The forces were measured between identical, opposing PNIPAM films and between a PNIPAM film and a lipid membrane. At the grafting densities and molecular weights investigated, the polymer extension did not change significantly above the LCST, and the polymers did not adhere. Below the LCST, the force-distance profiles suggest a vertical phase separation, which results in a diluter outer layer and a dense surface proximal layer. At large separations, the force profiles agree qualitatively with simple polymer theory but deviate at small separations. Importantly, at these low grafting densities and molecular weights, the end-grafted PNIPAM does not collapse above the LCST. This finding has direct implications for triggering liposomal drug release with end-grafted PNIPAM, but it increases the temperature range where these short PNIPAM chains function as steric stabilizers.

Electrooxidation of Methanol on upd-Ru and upd-Sn Modified Pt Electrodes

The electrochemical oxidation of methanol has been investigated on underpotentially deposited-ruthenium-modified platinum electrode (upd-Ru/Pt) and on underpotentially deposited-tin-modified platinum electrode (upd-Sn/Pt). The submonolayers of upd-Ru and upd-Sn on a Pt electrode increased the rate of methanol electrooxidation several times as large as that on a pure Pt electrode. The best performance for methanol electrooxidation was obtained on a ternary platinum based catalyst modified by upd-Ru and upd-Sn simultaneously. The influence of the submonolayers of upd-Ru adatoms and upd-Sn adatoms on the oxidation of methanol in acid has been investigated. The effect of Ru on methanol electrooxidation lies on the distribution of Ru adatoms on a Pt surface. It has been shown that as long as the amount of upd-Ru deposits were controlled in a proper range, upd-Ru deposits would enhance the methanol oxidation obtained on a Pt electrode at whichever deposition potential the upd-Ru deposits were obtained. The effects of tin are sensible to the potential range. The enhancement effect of upd-Sn adatoms for the oxidation of methanol will disappear as the electrode potential is beyond a certain value. It is speculated that there exists a synergetic effect on the Pt electrode as adatoms Ru and Sn participate simultaneously in the methanol oxidation.

Identification of an histone H3 acetylated/K4-methylated-bound intragenic enhancer regulatory for urokinase receptor expression

The transcriptionally regulated urokinase-type plasminogen activator receptor (u-PAR) contributes to cancer progression. Although previous studies have identified multiple 5' regulatory elements, these cis motifs cannot fully account for u-PAR expression prompting a search for hitherto uncharacterized regulatory elements. DNase I hypersensitivity and chromatin immunoprecipitation assays using u-PAR-expressing colon cancer cells indicated a hypersensitive region (+665/+2068) in intron 1 enriched with acetylated histone 3 (H3) and H3 methylated at lysine 4, markers of regulatory regions. The +665/+2068 region increased transcription from a u-PAR-promoter in an orientation- and distance-independent manner fulfilling the criteria of an enhancer. Optimal stimulation of the u-PAR promoter by phorbol ester required this enhancer. Systematic truncations combined with DNase I footprinting revealed two protected regions (+1060/+1099 and +1123/+1134) with deletion of the latter practically abolishing enhancer activity. The +1123/+1134 region harbored non-consensus activator protein-1 and Ets1 binding sites bound with c-Jun (and/or the related JunD/JunB) and c-Fos (and/or the related FosB/Fra-1/Fra-2) as revealed with chromatin immunoprecipitation. Further, nuclear extract from resected colon cancers showed elevated protein binding to a +1123/+1134-spanning probe coordinate with elevated u-PAR protein. Thus, we have defined a novel intragenic enhancer in the u-PAR gene required for constitutive and inducible expression.

Transcatheter closure of patent ductus arteriosus with severe pulmonary arterial hypertension in adults

BACKGROUND

Surgical closure of patent ductus arteriosus (PDA) with severe pulmonary arterial hypertension in adults carries higher risk than in children.

OBJECTIVES

To investigate the application of self-expandable occluders for transcatheter closure of PDA associated with severe pulmonary arterial hypertension in adults, and the assessment of immediate and short-term results.

METHODS

29 adult patients (6 men, 23 women) underwent attempted transcatheter closure of PDA at a mean (standard deviation (SD)) age of 31.1 (11.4) years (range 18-58 years) and a mean (SD) weight of 54.1 (7.1) kg (range 42-71 kg). On the basis of haemodynamic and clinical data obtained before and after trial occlusion, the final duct occlusion was determined and carried out. Radiographs of the chest, electrocardiograms and echocardiograms were used for follow-up evaluation of the treatment within 1 day, 1 month and 3-6 months after successful closure.

RESULTS

20 of the 29 patients had successful occlusion (group 1), and 9 patients failed (named group 2). In group 1, in which occlusion was successful, mean (SD) pulmonary arterial pressures decreased markedly after trial occlusion: 78 (19.3) mm Hg (range 50-125 mm Hg) before occlusion and 41 (13.8) mm Hg (range 23-77 mm Hg) after occlusion. Systemic arterial oxygen saturation was found to be >90% in 19 patients and <90% in the remaining patient before inhalation of oxygen, and >95% during inhalation of oxygen or after occlusion in all 20 patients. In group 2, the occlusion was not successful, because in two patients the device was not available; another two patients showed worsening of symptoms. The other five patients showed increased pulmonary arterial pressures after trial closure; their mean (SD) pulmonary arterial pressures increased by 10.3 (6) mm Hg (4-16 mm Hg) after trial occlusion, and systemic arterial oxygen saturation was 85.5% (2.6%) (range 82.6-88%) before inhalation of oxygen and 94.7% (1.7%) (range 90.7-99.1%) during inhalation of oxygen. In group 1, the dimensions of the left atrium, left ventricle and pulmonary artery increased considerably in 3-6-months of follow-up compared with those of preocclusion.

CONCLUSIONS

Transcatheter closure is an effective treatment for adults with PDA associated with reversible severe pulmonary arterial hypertension. Further research is needed for the evaluation of long-term results.

Cyclooxygenase-2 expression is associated with VEGF-C and lymph node metastases in gastric cancer patients

Previous studies have suggested that cyclooxygenase-2 (COX-2) over-expression is associated with angiogenesis in gastric cancer. However, the relationship between COX-2 and lymphangiogenesis is still unclear. The aim of this study was to determine the relationship between COX-2 expression and lymphangiogenic factor, vascular endothelial growth factor-C (VEGF-C), in human gastric cancer, as well as to correlate with clinicopathological parameters. Sixty-three gastric cancer patients underwent radical gastrectomy (D2 or D3) were enrolled in this study. The expression of COX-2 and VEGF-C were detected by immunohistochemistry, and the small lymphatic vessels were immunohistochemically stained by LYVE-1 antibody. The association between COX-2 and VEGF-C expressions and clinicopathological parameters (such as gender, tumor location, lymph node status and Lauren classification) were determined. VEGF-C over-expression was observed in 33 of 63 patients (52%), while COX-2 over-expression occurred in 42 of 63 tumor samples (67%). Presence of microlymphatic vessels with LYVE-1 staining was found in 35 cases. COX-2 over-expression was highly correlated with VEGF-C over-expression (P = 0.032), microlymphatic vessels (P = 0.002) as well as presence of metastatic lymph nodes (P = 0.007). However, no significant correlation was found between COX-2 expression and other clinicopathological parameters. Our data suggest that COX-2 expression is associated with lymphangiogenesis and lymph node metastasis in human gastric carcinoma. This raises the possibility that COX-2-mediated VEGF-C over-expression might promote lymph node metastasis via lymphangiogenesis pathway in patients with gastric cancer.

A new congenital form of X-linked autophagic vacuolar myopathy

In a new family with X-linked congenital autophagic vacuolar myopathy (AVM), seven affected boys presented with congenital hypotonia, dyspnea, and dysphagia with delayed motor milestones. Muscle pathology revealed autophagic vacuoles with sarcolemmal features, multilayered basal lamina with marked sarcolemmal deposition of C5-9 membrane attack complex and calcium, histologically indistinguishable from childhood-onset X-linked myopathy with excessive autophagy (XMEA). Haplotype analysis suggests that this new AVM and XMEA may be allelic despite different clinical presentations.

Inhibition of growth and increase of alkaline phosphatase activity in cultured human oral cancer cells by all-trans retinoic acid

In this study, the effects of all-trans retinoic acid (ATRA) on human oral cancer cells with regard to cell growth, the cell cycle, and alkaline phosphatase (ALP) activity were evaluated. Human oral cancer KB cells were treated with various concentrations of ATRA, and cell growth was then determined using the MTT viability assay. The cell-cycle distribution and ALP activity were analysed using a flow cytometer and chemical analyser, respectively. The KB cells were inhibited by ATRA at concentrations of 1-16 microM (1 microM, P<0.05; 2 microM, P<0.01; 4, 8 and 16 microM, P<0.001) in a dose-dependent manner. ATRA arrested KB cells in the G0/G1 phase. The ALP activity in KB cells was increased by ATRA. This is one of the first studies to focus on the expression of ALP in human head-and-neck carcinoma cells treated with retinoids. These findings suggest that the anti-tumour effects of ATRA on human oral cancer are associated with G0/G1 phase arrest and an increase in ALP activity.

A prediction rule for clinical diagnosis of severe acute respiratory syndrome

A prospective study was undertaken to identify clinical, radiographical, haematological and biochemical profiles of severe acute respiratory syndrome (SARS) patients. A prediction rule, which demarcates low from high risk patients for SARS in an outbreak situation was developed. A total of 295 patients with unexplained respiratory illnesses, admitted to Queen Mary Hospital, Hong Kong SAR, China, in March to July 2003, were evaluated for clinical, radiological, haematological and alanine transaminase (ALT) data daily for 3 days after hospitalisation. In total, 44 cases were subsequently confirmed to have SARS by RT-PCR (68.2%) and serology (100%). The scoring system of attributing 11, 10, 3, 3 and 3 points to the presence of independent risk factors, namely: epidemiological link, radiographical deterioration, myalgia, lymphopenia and elevated ALT respectively, generated high and low-risk (total score 11-30 and 0-10, respectively) groups for SARS. The sensitivity and specificity of this prediction rule in positively identifying a SARS patient were 97.7 and 81.3%, respectively. The positive and negative predictive values were 47.8 and 99.5%, respectively. The prediction rule appears to be helpful in assessing suspected patients with severe acute respiratory syndrome at the bedside, and should be further validated in other severe acute respiratory syndrome cohorts.

Computational biomechanical modelling of the lumbar spine using marching-cubes surface smoothened finite element voxel meshing

There is a need for the development of finite element (FE) models based on medical datasets, such as magnetic resonance imaging and computerized tomography in computation biomechanics. Direct conversion of graphic voxels to FE elements is a commonly used method for the generation of FE models. However, conventional voxel-based methods tend to produce models with jagged surfaces. This is a consequence of the inherent characteristics of voxel elements; such a model is unable to capture the geometries of anatomical structures satisfactorily. We have developed a robust technique for the automatic generation of voxel-based patient-specific FE models. Our approach features a novel tetrahedronization scheme that incorporates marching-cubes surface smoothing together with a smooth-distortion factor (SDF). The models conform to the actual geometries of anatomical structures of a lumbar spine segment (L3). The resultant finite element analysis (FEA) at the surfaces is more accurate compared to the use of conventional voxel-based generated FE models. In general, models produced by our method were superior compared to that obtained using the commercial software ScanFE.

Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.

Inhaled fluticasone in bronchiectasis: a 12 month study

BACKGROUND

The clinical efficacy of inhaled corticosteroid (ICS) treatment has not been evaluated in bronchiectasis, despite the presence of chronic airway inflammation.

METHODS

After three consecutive weekly visits, 86 patients were randomised to receive either fluticasone 500 mug twice daily (n = 43, 23F, mean (SD) age 57.7 (14.4) years) or matched placebo (n = 43, 34F, 59.2 (14.2) years) and reviewed regularly for 52 weeks in a double blind fashion.

RESULTS

35 and 38 patients in the fluticasone and placebo groups completed the study. Significantly more patients on ICS than on placebo showed improvement in 24 hour sputum volume (OR 2.5, 95% CI 1.1 to 6.0, p = 0.03) but not in exacerbation frequency, forced expiratory volume in 1 second, forced vital capacity, or sputum purulence score. Significantly more patients with Pseudomonas aeruginosa infection receiving fluticasone showed improvement in 24 hour sputum volume (OR 13.5, 95% CI 1.8 to 100.2, p = 0.03) and exacerbation frequency (OR 13.3, 95% CI 1.8 to 100.2, p = 0.01) than those given placebo. Logistic regression models revealed a significantly better response in sputum volume with fluticasone treatment than with placebo among subgroups of patients with 24 hour sputum volume <30 ml (p = 0.04), exacerbation frequency </=2/year (p = 0.04), and sputum purulence score >5 (p = 0.03).

CONCLUSIONS

ICS treatment is beneficial to patients with bronchiectasis, particularly those with P. aerurginosa infection.