Biomedical subjects

A Wang

Publications and source records attributed to A Wang.

At least 19 recordsLinked to original sources

PubMed2007

Correlation of Neo-Sensitabs tablet diffusion assay results on three different agar media with CLSI broth microdilution M27-A2 and disk diffusion M44-A results for testing susceptibilities of Candida spp. and Cryptococcus neoformans to amphotericin B, caspofungin, fluconazole, itraconazole, and voriconazole.

We compared the Neo-Sensitabs tablet assay to both reference M27-A2 broth microdilution and M44-A disk diffusion methods for testing susceptibilities of 110 isolates of Candida spp. and Cryptococcus neoformans to amphotericin B, caspofungin, fluconazole, itraconazole, and voriconazole. Neo-Sensitabs assay inhibition zone diameters in millimeters on three agars (Mueller-Hinton agar supplemented with 2% dextrose and 0.5 microg/ml methylene blue [MGM], Shadomy [SHA], and RPMI 1640 [RPMI, 2% dextrose]) were obtained at 24 to 72 h. The correlation coefficient of Neo-Sensitabs results with MICs was similar to that of the disk method for most of the five agents on MGM (R, 0.80 to 0.89 versus 0.76 to 0.89, respectively). Overall, superior correlation was observed at 24 h for most agents. The exception was amphotericin B (R values of 0.68 and 0.5 for disk and tablet, respectively, at 48 h versus 0.68 and 0.48, respectively, at 24 h). In general, Neo-Sensitabs results were less consistent on SHA and RPMI agars. Although agreement by breakpoint category of Neo-Sensitabs and disk results with CLSI method M27-A2 was also similar on MGM (92.7 to 98.2% versus 95.5 to 100%, respectively), the Neo-Sensitabs method failed to identify two of the six isolates with high amphotericin B MICs. These data suggest the potential value of the Neo-Sensitabs assay for testing at least four of the five agents against yeasts evaluated in the clinical laboratory.

Amphotericin B↗

PubMed2006

Genistein inhibits Brca1 mutant tumor growth through activation of DNA damage checkpoints, cell cycle arrest, and mitotic catastrophe.

Epidemiological studies revealed that amount of consumption of soy was inversely related to incidence of breast cancer. Genistein, the predominant isoflavone in soy, has been reported to reduce the incidence of breast cancer in animal models. To investigate whether genistein has a therapeutic effect on BRCA1-associated breast cancer, we treated Brca1 mutant mammary tumor cells with genistein. We showed that genistein treatment depleted the G1 population of cells, which was accompanied by an accumulation of cells at G2. Some genistein-treated cells entered mitosis; however, they exhibited chromosome abnormalities and maintained tetraploidy owing to abortive mitotic exit. A fraction of G2 cells underwent endoreduplication and became polyploid, which was accompanied by increased cell death through activating DNA damage response. Furthermore, our data indicated that Brca1 mutant cells were more sensitive to genistein than some other types of cancer cells, highlighting a good therapeutic potential of genistein for BRCA1-associated breast cancer.

Animals↗

PubMed2006

Anaesthetist's responses to patients' self-reported drug allergies.

BACKGROUND: Patients with drug allergies are commonplace in anaesthetic practice. We investigated the incidence and nature of drug 'allergies' reported by surgical patients attending a hospital pre-admission clinic, and went on to ascertain to what degree drug allergies recorded in the records influenced drug prescribing during the patients' hospital stay and determine whether any adverse events occurred in relation to drug prescribing in this population. METHODS: Patients attending for anaesthetic assessment at a Pre-Admission Clinic over a 30 week period were questioned concerning drug allergies. Medical records of these patients were then examined after their hospitalization to assess medications prescribed during that period. RESULTS: Of 1260 patients attending the Pre-admission clinic during the study period 420 (33.4%) claimed to have a total of 644 individual drug 'allergies'. The most common agents implicated were antibiotics (n=272), opioid analgesics (n=118) and NSAIDs (n=62); the most common form of these reactions were dermatological (n=254) and nausea and vomiting (n=124). There were 41 self-reports specifically of anaphylaxis and a further 61 where there was significant respiratory system involvement. CONCLUSIONS: The majority of the self-reported allergies were in fact simply accepted adverse effects of the drugs concerned. The patients' reported drug 'allergy' history was generally well respected by anaesthetists and other medical staff. There were 13 incidents, mainly involving morphine, where patients were given a drug to which they had claimed a specific allergy. There were 101 incidents in 89 patients where drugs of the same pharmacological group as that of their allergic drug were used. There were no untoward reactions in 84 patients who had claimed a prior adverse reaction to penicillin who were given cephalosporins. There were no sequelae from any other events. While anaesthetists generally respected patients self-reported 'allergies', more attention needs to be paid to the accurate recording of patients' events and a clear distinction should be made both in medical records and to the patient between true drug allergy and simple adverse drug reactions.

Adult↗

PubMed2006

Cloning and molecular characterization of three novel LMW-i glutenin subunit genes from cultivated einkorn (Triticum monococcum L.).

Three novel low molecular weight (LMW) glutenin subunits from cultivated einkorn (Triticum monococcum L., A(m)A(m), 2n = 2x = 14) were characterized by SDS-PAGE and molecular weights determined by MALDI-TOF-MS. Their coding genes were amplified and cloned with designed AS-PCR primers, revealing three complete gene sequences. All comprised upstream, open reading frame (ORF), downstream and no introns were present. The deduced amino acid sequences showed that all three genes, named as LMW-M1, LMW-M3 and LMW-M5, respectively, belonged to the LMW-i type subunits with the predicted molecular weight between 38.5206 and 38.7028 kDa. They showed high similarity with other LMW-i type genes from hexaploid bread wheats, but also displayed unique features. Particularly, LMW-M5 subunit contained an extra cysteine residue in the C-terminus except for eight conserved cysteines, which resulted from a single-nucleotide polymorphism (SNP) of the T-C transition, namely arginine --> cysteine substitution at position 242 from the N-terminal end. This is the first report that the LMW-i subunit contained nine cysteines residues that could result in a more highly cross-linked and more elastic glutenin suggesting that LMW-M5 gene may associates with good quality properties. In addition, a total of 25 SNPs and one insertions/deletions (InDels) were detected among three LMW-i genes, which could result in significant functional changes in polymer formation of gluten. It is anticipated that these SNPs could be used as reliable genetic markers during wheat quality improvement. The phylogenetic analysis indicated that LMW-i type genes apparently differed from LMW-m and LMW-s type genes and diverged early from the primitive LMW-GS gene family, at about 12.92 million years ago (MYA) while the differentiation of A(m) and A genomes was estimated at 3.98 MYA.

Amino Acid Sequence↗

PubMed2006

Three-level neodymium fiber laser incorporating photonic bandgap fiber.

We report a neodymium fiber laser incorporating an all-solid photonic bandgap fiber to suppress the four-level laser transition 4F(3/2)-4I(11/2). We demonstrate lasing at 907 nm on the three-level transition 4F(3/2)-4I(9/2) when pumping at 808 nm. The maximum slope efficiency obtained was 32% with a threshold pump power of 70 mW.

Journal Article↗

PubMed2006

Inducible nitric oxide synthase activity is essential for inhibition of prostatic tumor growth by interferon-beta gene therapy.

We have previously reported that adenoviral vector-mediated interferon (IFN)-beta gene therapy inhibits orthotopic growth of human prostate cancer cells in nude mice. The purpose of this study was to determine efficacy and mechanisms of this therapy in immune-competent mice. TRAMP-C2Re3 mouse prostate cancer cells infected with 100 multiplicity of infection (MOI) of adenoviral vector encoding for mouse IFN-beta (AdmIFN-beta), but not AdE/1 (a control adenoviral vector), produced approximately 60 ng/10(5) cells/24 h of IFN-beta. The tumorigenicity of AdmIFN-beta-transduced cells was dramatically reduced in the prostates of C57BL/6 mice. A single intratumoral injection of 2 x 10(9) PFU (plaque-forming unit) of AdmIFN-beta inhibited tumor growth by 70% and prolonged survival of tumor-bearing mice. Intriguingly, this AdmIFN-beta therapy did not alter the growth of tumors in inducible nitric oxide synthase (iNOS)-null C57BL/6 mice. Immunohistochemical analysis revealed that treatment of tumors with AdmIFN-beta in wild-type C57BL/6 mice led to increased iNOS expression, decreased microvessel density, decreased cell proliferation, and increased apoptosis. Furthermore, quantitative reverse-transcriptional PCR analysis showed that AdmIFN-beta therapy, in C57BL/6 but not the iNOS-null counterparts, reduced levels of the mRNAs for angiopoietin, basic fibroblast growth factor, matrix metalloproteinase-9, transforming growth factor-beta1, vascular endothelial growth factor (VEGF)-A, and VEGF-B, as well as the antiapoptotic molecule endothelin-1. These data indicated that IFN-beta gene therapy could be effective alternative for the treatment of locally advanced prostate cancer and suggest an obligatory role of NO in IFN-beta antitumoral effects in vivo.

Adenoviridae↗

PubMed2005

Immune modulation by a high molecular weight fraction from the rat tapeworm Hymenolepis diminuta.

The host-parasite relationship is exquisitely specific. In exploiting the host niche, a variety of helminth parasites have been shown to directly manipulate their hosts' immune responses. We assessed the ability of a whole-worm extract of Hymenolepis diminuta to modulate immune cell activation. Immune cells isolated from human blood or rodent spleens were activated with the T cell mitogen, concanavalin A (Con A) +/- H. diminuta extract and cytokine production (i.e. IL-2, -4, -10, -12) and proliferation assessed by ELISA and [3H]thymidine incorporation 24 and 72 h post-treatment, respectively. Co-treatment with the H. diminuta extract (100 microg protein/ml) virtually abolished Con A-induced immune cell proliferation, which was not due to increased apoptosis. Boiling of the worm extract reduced its anti-proliferative effect and fractionation indicated that a > 50 kDa component was predominantly responsible for the inhibition of Con A-induced immune cell proliferation. Cytokine determinations revealed that the H. diminuta extract significantly reduced Con A-stimulated IL-2 and IL-4, but enhanced the production of IFNy, IL-12 and IL-10. The increased IL-12 was due to an LPS contaminant in the extract and a helminth-derived 'IL-12'-like peptide that bound in the ELISA and Western blots. In contrast, a H. diminuta-derived factor directly stimulated IL-10 production by murine splenocytes, and contaminating LPS synergistically enhanced the production of IL-10. Thus, H. diminuta has the potential to block stimulated T cell proliferation and, by inhibiting IL-4 and promoting IL-10 production, may bias the immune environment towards one of immunoregulation and away from IL-4 dominated T helper 2 type events.

Animals↗

PubMed2004

Basaltic rocks analyzed by the Spirit Rover in Gusev Crater.

The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain </=25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mössbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.

Extraterrestrial Environment↗

PubMed2004

Localization and physical properties experiments conducted by Spirit at Gusev Crater.

The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials.

Extraterrestrial Environment↗

PubMed2004

Textures of the soils and rocks at Gusev Crater from Spirit's Microscopic Imager.

The Microscopic Imager on the Spirit rover analyzed the textures of the soil and rocks at Gusev crater on Mars at a resolution of 100 micrometers. Weakly bound agglomerates of dust are present in the soil near the Columbia Memorial Station. Some of the brushed or abraded rock surfaces show igneous textures and evidence for alteration rinds, coatings, and veins consistent with secondary mineralization. The rock textures are consistent with a volcanic origin and subsequent alteration and/or weathering by impact events, wind, and possibly water.

Extraterrestrial Environment↗

PubMed2004

Wind-related processes detected by the Spirit Rover at Gusev Crater, Mars.

Wind-abraded rocks, ripples, drifts, and other deposits of windblown sediments are seen at the Columbia Memorial Station where the Spirit rover landed. Orientations of these features suggest formative winds from the north-northwest, consistent with predictions from atmospheric models of afternoon winds in Gusev Crater. Cuttings from the rover Rock Abrasion Tool are asymmetrically distributed toward the south-southeast, suggesting active winds from the north-northwest at the time (midday) of the abrasion operations. Characteristics of some rocks, such as a two-toned appearance, suggest that they were possibly buried and exhumed on the order of 5 to 60 centimeters by wind deflation, depending on location.

Evolution, Planetary↗

PubMed2004

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater.

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Atmosphere↗

PubMed2004

Random-hole optical fiber evanescent-wave gas sensing.

Research on development of optical gas sensors based on evanescent-wave absorption in random-hole optical fibers is described. A process to produce random-hole optical fibers was recently developed that uses a novel in situ bubble formation technique. Gas molecules that exhibit characteristic vibrational absorption lines in the near-IR region that correspond to the transmission window for silica optical fiber have been detected through the evanescent field of the guided mode in the pore region. The presence of the gas molecules in the holes of the fiber appears as a loss at wavelengths that are characteristic of the particular gas species present in the holes. An experimental setup was constructed with these holey fibers for detection of acetylene gas. The results clearly demonstrate the characteristic absorptions in the optical spectra that correspond to the narrow-line absorptions of the acetylene gas, and this represents what is to our knowledge the first report of random-hole fiber gas sensing in the literature.

Journal Article↗

PubMed2004

The effects of lubricant composition on in vitro wear testing of polymeric acetabular components.

Lubricant composition is known to affect in vitro (simulator) wear of polymeric acetabular components. Clinical acetabular components, fabricated from both ultrahigh molecular weight polyethylene (UHMWPE) and polytetrafluoroethylene (PTFE), were tested against cobalt-chromium 32-mm ball heads, with the use of various lubricants, with different compositions and concentrations of bovine and calf serum as well as hyaluronic acid, in tests which lasted one million cycles. The type of proteins and their relative concentration in the lubricant affected the wear rate of both UHMWPE and PTFE. Increasing protein concentration reduced the UHMWPE wear rate but increased the PTFE wear rate. For a given total protein concentration, increasing the albumin/globulin (A/G) ratio led to a significant reduction in the wear rate for PTFE. A similar but smaller effect was found for UHMWPE. The relative wear-rate ratio between PTFE and UHMWPE depends on both the total protein concentration and the specific protein concentration (albumin/globulin ratio). The average clinical wear rates for both PTFE and UHMWPE and the average wear-rate ratios between them were reproduced when the serum lubricant contained total protein concentration and A/G ratio within normally observed physiological ranges. It is recommended that lubricants for simulator testing be standardized to control total protein content as well as albumin/globulin ratio.

Albumins↗

PubMed2004

The role of supinator in the pathogenesis of chronic lateral elbow pain: a biomechanical study.

The relative contributions of the forearm extensors to the tensile force at the lateral epicondyle were examined by implanting a force transducer in the common extensor tendon of four soft fixed cadaver elbows and sequentially stretching each muscle arising from the lateral epicondye. Extensor carpi radialis brevis and extensor digitorum communis produced the largest increases while the superficial head of supinator produced a moderate increase in tensile force in the common extensor tendon. Extensor carpi radialis longus and extensor carpi ulnaris had no significant effect. Radial tunnel pressure was measured using a balloon catheter in a separate study of five cadaver elbows. Radial tunnel pressure increased on moving the wrist from neutral to a flexion-pronation position. This positional rise in pressure was reduced by supinator musculotendinous lengthening (77%) while lengthening of the extensor carpi radialis brevis and extensor digitorum communis had no effect. This study demonstrates a biomechanical basis for the superficial head of supinator in the aetiology of both lateral epicondylitis and radial tunnel syndrome.

Analysis of Variance↗

PubMed2004

Analysis of a retrieved UHMWPE acetabular cup crosslinked in air with 1000 kGy of gamma radiation.

The oxidation and degradation that accompany high dose gamma irradiation in air for crosslinking and sterilization are important because they could affect the clinical performance of polyethylene total joint implants. We report a clinical case of a 1000 kGy gamma-irradiated, highly crosslinked ultra-high molecular weight polyethylene acetabular cup retrieved 24 years postoperatively. Performance evaluations included absorbed radiation dose, total wear penetration, average wear rate, crystallinity, oxidation, and equibiaxial tensile properties. A retrieved acetabular cup of the same grade of polyethylene but gamma-sterilized using a conventional dose was used as control. The highly crosslinked and control cups took in about 1300 and 30 kGy of radiation, respectively, as measured using a trans-vinylene index. Direct dimensional measurements revealed average wear rates of the highly crosslinked and control cups were 0.04 and 0.06 mm/year, respectively. The oxidation index of the highly crosslinked cup was very high (0.679), but equivalent to that of a 1000 kGy irradiated reference cup. The retrieved highly crosslinked cup showed much higher equibiaxial ultimate tensile strength than the retrieved control cup. Based on these observations, the increased wear resistance and equibiaxial tensile properties that resulted from extensive crosslinking in the presence of air were partially offset by the adverse effects caused by immediate oxidation during the process.

Aged↗

PubMed2004

Further evidence for paternal inheritance of mitochondrial DNA in the sheep (Ovis aries).

The mitochondrial DNA of 172 sheep from 48 families were typed by using PCR-RFLP, direct amplification of the repeated sequence domain and sequencing analysis. The mitochondrial DNA from three lambs in two half-sib families were found to show paternal inheritance. Our findings provide direct evidence of paternal inheritance of mitochondria DNA in sheep. A total of 12 highly polymorphic microsatellite markers, which mapped on different chromosomes, were employed to type the sheep population to confirm family relationships. Possible mechanisms of paternal inheritance are discussed.

Animals↗

PubMed2004

Intracytoplasmic sperm injection. Accomplishments and qualms.

AIM: Intracytoplasmic sperm injection (ICSI) is now the preferred technique for treatment of male factor infertility and many children have been born worldwide. However, concerns about the risk of transmitting genetic defects and development of ICSI children have been raised. We report clinical outcome of ICSI in Cornell University and results of screening for genetic defects in ICSI parents and their children. METHODS: Pregnancy and obstetrical outcomes as well as congenital malformations were analyzed. Chromosomal karyotyping and Yq deletion assessments were performed on blood samples. In addition, medical and developmental outcome were assessed in 3 and 5 year old ICSI children. RESULTS: We have performed 8 575 ICSI cycles with ejaculated spermatozoa that resulted in a 75.4% fertilization and a 42.8% clinical pregnancy rates while for surgically retrieved specimen resulted in 66%, 48.8% respectively. The incidence of Y deletion was within the expected range for an infertile population, with identical deletions transmitted to the male offspring. There were no differences in cognitive, motor and behavioral development observed between ICSI children and these conceived naturally. CONCLUSION: The large majority of infertile men were treatable by ICSI, which resulted in the transmission of a specific abnormality but did not enhance the incidence of de novo deletions. There is no indication that ICSI children develop more congenital defects or express a lower psychomotor development that children conceived naturally. Nonetheless, genetic screening and counseling of couples undergoing ICSI would seem to be appropriate.

Adult↗