The Effect of Chitosan Derivatives on the Compaction and Tension Generation of the Fibroblast-populated Collagen Matrix.

Fibrotic diseases, such as Dupuytren's contracture (DC), involve excess scar tissue formation. The differentiation of fibroblasts into myofibroblasts is a significant mechanism in DC, as it generates tissue contraction in areas without wound openings, leading to the deposition of scar tissue, and eventually flexing one or more fingers in a restrictive fashion. Additionally, DC has a high recurrence rate. Previously, we showed that N-dihydrogalactochitosan (GC), an immunostimulant, inhibited myofibroblast differentiation in a DC fibroblast culture. Our goal of this study was to expand our previous study to include other DC and normal cell lines and other chitosan derivatives (GC and single-walled carbon nanotube-conjugated GC) to determine the specific mechanism of inhibition. Derivative-incorporated and vehicle control (water) anchored fibroblast-populated collagen matrices (aFPCM) were used to monitor compaction (anchored matrix height reduction) using microscopy and optical coherence tomography (OCT) for six days. Fibroblasts were unable to compact chitosan derivative aFPCM to the same extent as vehicle control aFPCM in repeated experiments. Similarly, chitosan derivative aFPCM contracted less than control aFPCM when released from anchorage. Proliferative myofibroblasts were identified by the presence of alpha smooth muscle actin via myofibroblast proliferative assay. In all tested conditions, a small percentage of myofibroblasts and proliferative cells were present. However, when aFPCM were treated with transforming growth factor-beta 1 (TGF-ß1), all tested samples demonstrated increased myofibroblasts, proliferation, compaction, and contraction. Although compaction and contraction were reduced, there was sufficient tension present in the chitosan derivative aFPCM to allow exogenous stimulation of the myofibroblast phenotype.

Nanomaterial Applications in Photothermal Therapy for Cancer.

As a result of their unique compositions and properties, nanomaterials have recently seen a tremendous increase in use for novel cancer therapies. By taking advantage of the optical absorption of near-infrared light, researchers have utilized nanostructures such as carbon nanotubes, gold nanorods, and graphene oxide sheets to enhance photothermal therapies and target the effect on the tumor tissue. However, new uses for nanomaterials in targeted cancer therapy are coming to light, and the efficacy of photothermal therapy has increased dramatically. In this work, we review some of the current applications of nanomaterials to enhance photothermal therapy, specifically as photothermal absorbers, drug delivery vehicles, photoimmunological agents, and theranostic tools.

Forensic Analysis of Cigarette Ash-Brand Determination Through Trace-metal Analysis.

The information inherent in cigarette ash in the form of trace-metal concentrations may be of use in a forensic context as it can indicate the brand from which the ash originated. This knowledge might help place suspects at crime scenes or determine how many people may have been present. To develop and test statistical models capable of classifying ash samples according to brand, commercial cigarettes procured in the U.S. and overseas were "smoked" using a peristaltic pump, mimicking the range of human smoking habits. Ash samples were digested in a mixture of nitric and hydrochloric acid applying microwave digestion and analyzed using inductively coupled plasma-mass spectrometry. Principal component analysis of the elemental data showed intrinsic differences between brands. Partial least squares-discriminant analysis demonstrated that brand classification yields good sensitivity and specificity for a number of models tested. Varying smoking parameters did not impact the classification of ash samples.

The quantitation of cocaine on U.S. currency: survey and significance of the levels of contamination.

It has long been suspected that the illicit distribution of cocaine in the United States has led to a large-scale contamination of the currency supply. To investigate the extent of contamination, 418 currency samples (4174 bills) were collected from 90 locations around the United States from 1993 to 2009. The extent of their cocaine contamination was quantitated via gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry. The level of cocaine contamination was determined to average 2.34 ng/bill across all denominations ($1, $5, $10, $20, $50, and $100). Levels of cocaine contamination on currency submitted to the Federal Bureau of Investigation Laboratory in criminal cases over the 1993-2001 timeframe had significantly higher contamination than currency in general circulation. A mathematical model was developed based on the background survey that indicates the likelihood of drawing a bill in specific concentration ranges. For example, there is a 0.8349 likelihood that random bill will have contamination less than 20 ng.

Volume, quality of care, and outcome in pneumonia.

BACKGROUND: The establishment of minimum volume thresholds has been proposed as a means of improving outcomes for patients with various medical and surgical conditions. OBJECTIVE: To determine whether volume is associated with either quality of care or outcome in the treatment of pneumonia. DESIGN: Retrospective cohort study. SETTING: 3243 hospitals participating in the National Pneumonia Quality Improvement Project in 1998 and 1999. PATIENTS: 13,480 patients with pneumonia cared for by 9741 physicians. MEASUREMENTS: The association between the annual pneumonia caseload of physicians and hospitals and adherence to quality-of-care measures and severity-adjusted in-hospital and 30-day mortality rates. RESULTS: Physician volume was unrelated to the timeliness of administration of antibiotics and the obtainment of blood cultures; however, physicians in the highest-volume quartile had lower rates of screening for and administration of influenza (21%, 19%, 20%, and 12% for quartiles 1 through 4, respectively; P < 0.01) and pneumococcal (16%, 13%, 13%, and 9% for quartiles 1 through 4, respectively; P < 0.01) vaccines. Among hospitals, the percentage of patients who received antibiotics within 4 hours of hospital arrival was inversely related to pneumonia volume (72%, 64%, 60%, and 56% for quartiles 1 through 4, respectively; P < 0.01), while selection of antibiotic, obtainment of blood cultures, and rates of immunization were similar. Physician volume was not associated with in-hospital or 30-day mortality rates. Odds ratios for in-hospital mortality rates rose with increasing hospital volume (1.14 [95% CI, 0.87 to 1.49], 1.34 [CI, 1.03 to 1.75], and 1.32 [CI, 0.97 to 1.80] for quartiles 2 to 4, respectively); however, odds ratios for 30-day mortality rates were similar. LIMITATIONS: This study was limited to Medicare beneficiaries 65 years of age and older. Ascertainment of some measures of the quality of care and severity of illness depended on the documentation practices of the physician. CONCLUSION: Among both physicians and hospitals, higher pneumonia volume is associated with reduced adherence to selected guideline recommendations and no measurable improvement in patient outcomes.

Blood culture and susceptibility results and allergy history do not influence fluoroquinolone use in the treatment of community-acquired pneumonia.

STUDY OBJECTIVE: To determine the influence of blood culture and susceptibility results and antimicrobial allergy history on fluoroquinolone use in the treatment of community-acquired pneumonia. DESIGN: Retrospective analysis of medical records. SETTING: Centers for Medicare and Medicaid Services, Seattle, Washington. PATIENTS: A total of 10,275 Medicare beneficiaries hospitalized with the diagnosis of pneumonia received antimicrobial treatment within 24 hours of admission. Of these patients, 288 had blood cultures positive for pneumococcus and were matched one-to-one with patients with negative blood and sputum cultures. MEASUREMENTS AND MAIN RESULTS: Antimicrobial use at the beginning and end of hospitalization, culture and susceptibility results, and patient allergies were recorded retrospectively and compared between two matched groups: patients with blood cultures positive for Streptococcus pneumoniae and those whose blood and sputum cultures were negative. Neither culture and susceptibility results nor allergy history affected the rate of fluoroquinolone use. Despite infection due to penicillin-susceptible pneumococci and no penicillin allergy, patients received therapy with fluoroquinolones (26.7%) as frequently as those with culture-negative pneumonia (34.9%; p=0.401). CONCLUSION: Fluoroquinolones are prescribed despite microbiologic confirmation of penicillin-susceptible pneumococcal pneumonia in the absence of penicillin allergy. These prescribing patterns may contribute to selection pressure associated with fluoroquinolone-resistant gram-positive and gram-negative bacteria.

Coronary artery bypass grafting surgery in Oklahoma: processes and outcomes of care.

Coronary artery bypass grafting (CABG) is a commonly performed operation on Oklahoma Medicare beneficiaries. In 1994, the Centers for Medicare & Medicaid Services funded a project to evaluate process-oriented quality improvement activities for this surgery. Structured medical record review was performed on the charts of 2,312 Oklahoma Medicare patients who had a CABG surgery between July 1, 1995, and June 30, 1996, and on 926 patients who had their surgery from July 1 through December 31, 1998. Demographic, procedural and outcome variables were abstracted from each medical record. In addition to summarizing the clinical and demographic characteristics, we evaluated inter-hospital variations in both processes and outcomes of care. Significant variations in care were demonstrated for the 13 Oklahoma hospitals in which this operation was performed. The results of this project suggest that there are substantial opportunities to improve the quality of care for CABG in Oklahoma.