Synthesis of a novel monofilament bioabsorbable suture for biomedical applications.

In this research, a novel bioabsorbable suture that is, monofilament and capable of localized drug delivery, was developed from a combination of natural biopolymers that where not previously applied for this purpose. The optimized suture formulation comprised of sodium alginate (6% wt/vol), pectin (0.1% wt/vol), and gelatin (3% wt/vol), in the presence of glycerol (4% vol/vol) which served as a plasticizer.

Synthetically Tunable White-, Green-, and Yellow-Green-Light Emission in Dual-Luminescent Gold(I) Complexes Bearing a Diphenylamino-2,7-fluorenyl Moiety.

The syntheses and photophysical characterization of five new gold(I) complexes bearing diphenylamine-substituted fluorenyl moieties are reported; four are characterized by X-ray diffraction crystallography. Ancillary ligation on gold(I) is provided by organophosphine and N-heterocyclic carbene ligands. Two complexes, and , are σ-aryls, two, and , are σ-alkynyls, and one, is a σ-triazolyl bound through carbon.

A single nucleobase tunes nonradiative decay in a DNA-bound silver cluster.

DNA strands are polymeric ligands that both protect and tune molecular-sized silver cluster chromophores. We studied single-stranded DNA CACTCXT with X = guanosine and inosine that form a green fluorescent Ag cluster, but these two hosts are distinguished by their binding sites and the brightness of their Ag adducts. The nucleobase subunits in these oligomers collectively coordinate this cluster, and fs time-resolved infrared spectra previously identified one point of contact between the C2-NH of the X = guanosine, an interaction that is precluded for inosine.

Advances in carbohydrate-based polymers for the design of suture materials: A review.

Suture materials constitute one of the largest biomedical material groups with a huge global market of $ 1.3 billion annually and employment in over 12 million procedures per year. Suture materials have radically evolved over the years, from basic strips of linen to more advanced synthetic polymer sutures.

The Hemocompatibility of Nanoparticles: A Review of Cell-Nanoparticle Interactions and Hemostasis.

Understanding cell-nanoparticle interactions is critical to developing effective nanosized drug delivery systems. Nanoparticles have already advanced the treatment of several challenging conditions including cancer and human immunodeficiency virus (HIV), yet still hold the potential to improve drug delivery to elusive target sites. Even though most nanoparticles will encounter blood at a certain stage of their transport through the body, the interactions between nanoparticles and blood cells is still poorly understood and the importance of evaluating nanoparticle hemocompatibility is vastly understated.

Isotopic substitution affects excited state branching in a DNA duplex in aqueous solution.

Changing the solvent from H2O to D2O dramatically affects the branching of the initial excited electronic states in an alternating G·C DNA duplex into two distinct decay channels. The slower, multisite PCET channel that deactivates more than half of all excited states in D2O becomes six times weaker in H2O.

Chemical cross-linking of a variety of green fluorescent proteins as Förster resonance energy transfer donors for Yukon orange fluorescent protein: A project-based undergraduate laboratory experience.

Förster resonance energy transfer (FRET) is the basis for many techniques used in biomedical research. Due to its wide use in molecular sensing, FRET is commonly introduced in many biology, chemistry, and physics courses. While FRET is of great importance in the biophysical sciences, the complexity and difficulty of constructing FRET experiments has resulted in limited usage in undergraduate laboratory settings.

Excited-State Dynamics of a DNA Duplex in a Deep Eutectic Solvent Probed by Femtosecond Time-Resolved IR Spectroscopy.

To better understand how the solvent influences excited-state deactivation in DNA strands, femtosecond time-resolved IR (fs-TRIR) pump-probe measurements were performed on a d(AT)·d(AT) duplex dissolved in a deep eutectic solvent (DES) made from choline chloride and ethylene glycol in a 1:2 mol ratio. This solvent, known as ethaline, is a member of a class of ionic liquids capable of solubilizing DNA with minimal disruption to its secondary structure. UV melting analysis reveals that the duplex studied here melts at 18 °C in ethaline compared to 50 °C in aqueous solution.

Excited-state dynamics of mononucleotides and DNA strands in a deep eutectic solvent.

The photophysics of several mono- and oligonucleotides were investigated in a deep eutectic solvent for the first time. The solvent glyceline, prepared as a 1 : 2 mole ratio mixture of choline chloride and glycerol, was used to study excited-state deactivation in a non-aqueous solvent by the use of steady-state and time-resolved spectroscopy. DNA strands in glyceline retain the secondary structures that are present in aqueous solution to some degree, thus enabling a study of the effects of solvent properties on the excited states of stacked bases and stacked base pairs.

Photoinduced long-lived charge transfer excited states in AT-DNA strands.

The IR spectrum of a charge transfer (CT) excited electronic state in DNA has been computed for the first time, enabling assignment of the long-lived component of the transient IR spectrum of a d(AT)9 single strand to an A → T CT state. Experimentally, the CT state lifetime is much shorter than in the double strand, and our calculations explain this result using Marcus Theory.

Excited-State Dynamics of DNA Duplexes with Different H-Bonding Motifs.

The excited-state dynamics of three distinct forms of the d(GC)9·d(GC)9 DNA duplex were studied by combined time-resolved infrared experiments and quantum mechanical calculations. In the B- and Z-forms, bases on opposite strands form Watson-Crick (WC) base pairs but stack differently because of salt-induced changes in backbone conformation. At low pH, the two strands associate by Hoogsteen (HG) base pairing.

UV-Induced Proton Transfer between DNA Strands.

UV radiation creates excited states in DNA that lead to mutagenic photoproducts. Photoexcitation of single-stranded DNA can transfer an electron between stacked bases, but the fate of excited states in the double helix has been intensely debated. Here, photoinduced interstrand proton transfer (PT) triggered by intrastrand electron transfer (ET) is detected for the first time by time-resolved vibrational spectroscopy and quantum mechanical calculations.

Deuterium isotope effect on excited-state dynamics in an alternating GC oligonucleotide.

Isotope effects on the excited-state dynamics of single- and double-stranded GC-containing DNAs were studied by femtosecond transient absorption spectroscopy. A pronounced deuterium isotope effect was observed in alternating d(GC)(9).d(GC)(9), but none was seen in the nonalternating or single-stranded variations investigated.

The excited-state lifetimes in a G x C DNA duplex are nearly independent of helix conformation and base-pairing motif.

DNA photophysics: Femtosecond transient absorption experiments reveal that excited states produced by UV light in a duplex DNA oligonucleotide decay at essentially the same rate in B and Z helix conformers (see figure).

DNA excited-state dynamics: from single bases to the double helix.

Ultraviolet light is strongly absorbed by DNA, producing excited electronic states that sometimes initiate damaging photochemical reactions. Fully mapping the reactive and nonreactive decay pathways available to excited electronic states in DNA is a decades-old quest. Progress toward this goal has accelerated rapidly in recent years, in large measure because of ultrafast laser experiments.

UV excitation of single DNA and RNA strands produces high yields of exciplex states between two stacked bases.

Excited electronic states created by UV excitation of the diribonucleoside monophosphates ApA, ApG, ApC, ApU, and CpG were studied by the femtosecond transient-absorption technique. Bleach recovery signals recorded at 252 nm show that long-lived excited states are formed in all five dinucleosides. The lifetimes of these states exceed those measured in equimolar mixtures of the constituent mononucleotides by one to two orders of magnitude, indicating that electronic coupling between proximal nucleobases dramatically slows the relaxation of excess electronic energy.

Ground-state recovery following UV excitation is much slower in G x C-DNA duplexes and hairpins than in mononucleotides.

Excited states in double-stranded oligonucleotides containing G.C base pairs were studied by femtosecond transient absorption spectroscopy. Relaxation to the electronic ground state occurs about 10 times more slowly in the duplexes and hairpins studied on average than in the individual mononucleotides of G and C.

[Effect of raloxifene hydrochloride on bone mineral density, bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis].

Objective: To determine the effect of raloxifene hydrochloride (RLX) on the lumbar spine and total hip bone mineral density (BMD), bone metabolism and serum lipids in Chinese postmenopausal women with osteoporosis.

Methods: 204 Chinese postmenopausal women with osteoporosis from 3 hospitals in Beijing and Shanghai were randomly divided into 2 groups of 102 women: RLX group (RLX of the dosage of 60 mg/day was given for 12 months) and placebo group. In addition, 500 mg of elemental calcium and 200 units of vitamin D were given daily to all women.

Horner's syndrome in the emergency department.

We present a case of a 47-year-old female who was followed for 7 months with complaints of musculoskeletal pain involving the shoulder and scapula until she presented to the emergency department with Horner's syndrome and was diagnosed as having a superior pulmonary sulcus tumor. A review of the literature shows that although such tumors are a frequent cause of Horner's syndrome there are numerous other benign as well as malignant causes of Horner's syndrome. The differential diagnosis can be significantly narrowed by a knowledge of the anatomy and a careful physical examination.

Saliva alcohol reagent strips in altered response protocols.

The prehospital care provider has been limited in his or her initial assessment of patients due to having available only a limited number of simple diagnostic tests. There has not been an accurate field test available to rule out significant ethanol intoxication. We designed a prospective trial for the prehospital setting to test the utility of a rapid, semi-quantitative, saliva alcohol reagent strip for patients with an altered level of consciousness.

Biogenesis of mitochondrial proteins. Regulation of production of delta-aminolaevulinate synthase by haemin in embryonic-chick liver.

The effect of haemin on the biogenesis of delta-aminolaevulinate synthase (ALA synthase) was investigated in primary cultures of embryonic-chick liver. The activity of the enzyme and the amount of the enzyme detected by 'immune-blotting' were determined in hepatocytes incubated with the porphyrogenic agent allylisopropylacetamide. The results of these studies indicated that the loss in ALA synthase activity in cells incubated in the presence of haemin (10 microM) was roughly proportional to a loss in the immune-reactive mass of the enzyme.

Isolation of the mature subunit of delta-aminolaevulinate synthase from embryonic chick liver.

We presented evidence indicating that the established procedure for purifying delta-aminolaevulinate (ALA) synthase from embryonic-chick liver yielded an enzyme with a partially degraded subunit of molecular weight 51000 [Ades & Harpe (1981) J. Biol. Chem.

Biogenesis of mitochondrial proteins. Identification of the mature and precursor forms of the subunit of delta-aminolevulinate synthase from embryonic chick liver.

The purpose of this study was to determine the molecular weights of the mature subunit of embryonic chick liver delta-aminolevulinate synthase and of its putative precursor fom. Although an active enzyme with a subunit molecular weight of 51,000 could be purified from the livers of porphyric embryos, it was determined by immunoreplicate electrophoresis analyses of sodium dodecyl sulfate-solubilized liver homogenates and mitochondria from porphyric embryos that the actual molecular weight of the enzyme's subunit was 65,000 +/- 2,000. These results suggested that the usual procedure for purifying delta-aminolevulinate synthase from chick embryo yielded a partially degraded enzyme.