Concentration of clarified pool by single-pass tangential flow filtration to improve productivity of protein A capture step: Impact of clarification strategies.

Protein A capture chromatography remains a high-cost and relatively low-productivity step for downstream processing of monoclonal antibodies. As bioprocessing transitions toward intensified processes, maximizing the efficiency of individual steps is key to achieving economic targets. This study was performed to assess the impact of inline concentration of clarified cell culture fluid (CCF), using single-pass tangential flow filtration, on protein A chromatography purification productivity. CCF with varying levels of impurities and turbidity were obtained dependent upon the clarification method. These CCFs were concentrated and processed over a protein A capture step. Productivity increases of 1.8- to 2.6-fold were achieved as compared to a protein A capture step with no CCF concentration. Achieving such targeted improvements requires careful consideration of the multiple components in the clarification strategy before implementation.

Proton stereotactic body radiation therapy for liver metastases-results of 5-year experience for 81 hepatic lesions.

BACKGROUND: To report on our institutional experience using Proton stereotactic body radiation therapy (SBRT) for patients with liver metastases. METHODS: All patients with liver metastases treated with Proton SBRT between September 2012 and December 2017 were retrospectively analyzed. Local control (LC) and overall survival (OS) were estimated using the Kaplan-Meier method calculated from the time of completion of Proton SBRT. LC was defined according to Response Evaluation Criteria in Solid Tumors (RECIST) guidelines (version 1.1). Toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. RESULTS: Forty-six patients with 81 lesions were treated with Proton SBRT. The median age was 65.5 years old (range, 33-86 years) and the median follow up was 15 months (range, 1-54 months). The median size of the gross tumor volume (GTV) was 2.5 cm (range, 0.7-8.9 cm). Two or more lesions were treated in 56.5% of patients, with one patient receiving treatment to a total of five lesions. There were 37 lesions treated with a biologically effective dose (BED) ≤60, 9 lesions with a BED of 61-80, 22 lesions with a BED of 81-100, and 13 lesions with a BED >100. The 1-year and 2-year LC for all lesions was 92.5% (95% CI, 82.7% to 96.8%). The grade 1 and grade 2 toxicity rates were 37% and 6.5%, respectively. There were no grade 3 or higher toxicities and no cases of radiation-induced liver disease (RILD). CONCLUSIONS: Proton SBRT for the treatment of liver metastases has promising LC rates with the ability to safely treat multiple liver metastases. Accrual continues for our phase II trial treating liver metastases with Proton SBRT to 60 GyE (Gray equivalent) in 3 fractions.

Experimental validation of magnetically focused proton beams for radiosurgery.

We performed experiments using a triplet of quadrupole permanent magnets to focus protons and compared their dose distributions with unfocused collimated beams using energies and field sizes typically employed in proton radiosurgery. Experiments were performed in a clinical treatment room wherein small-diameter proton beams were focused by a magnet triplet placed immediately upstream of a water tank. The magnets consisted of segments of Sm2Co17 rare-earth permanent magnetic material adhered into Halbach cylinders with nominal field gradients of 100, 150, 200, and 250 T m-1. Unmodulated beams with initial diameters of 3 mm-20 mm were delivered using a single scattering system with nominal energies of 127 and 157 MeV (respective ranges of ~10 cm and 15 cm in water), commonly used for proton radiosurgery at our institution. For comparison, small-diameter unfocused collimated beams were similarly delivered. Transverse and depth dose distributions were measured using radiochromic film and a diode detector, respectively, and compared between the focused and unfocused beams (UNF). The focused beams produced low-eccentricity beam spots (defined by the 80% dose contour) at Bragg depth, with full width at 80% maximum dose values ranging from 3.8 to 7.6 mm. When initial focused beam diameters were larger than matching unfocused diameters (19 of 29 cases), the focused beams peak-to-entrance dose ratios were 13% to 73% larger than UNF. In addition, in 17 of these cases the efficiency of dose delivery to the target was 1.3× to 3.3× larger. Both peak-to-entrance dose ratios and efficiency tended to increase with initial beam diameter, while efficiency also tended to increase with magnet gradient. These experimental results are consistent with our previous Monte Carlo (MC) studies and suggest that a triplet of quadrupole Halbach cylinders could be clinically useful for irradiating small-field radiosurgical targets with fewer beams, lower entrance dose, and shorter treatment times.

Financial indicators for critical access hospitals.

CONTEXT: There is a growing recognition of the need to measure and report hospital financial performance. However, there exists little comparative financial indicator data specifically for critical access hospitals (CAHs). CAHs differ from other hospitals on a number of dimensions that might affect appropriate indicators of performance, including differences in Medicare reimbursement, limits on bed size and average length of stay, and relaxed staffing rules. PURPOSE: To develop comparative financial indicators specifically designed for CAHs using Medicare cost report data. METHODS: A technical advisory group of individuals with extensive experience in rural hospital finance and operations provided advice to a research team from the University of North Carolina at Chapel Hill. Twenty indicators deemed appropriate for assessment of CAH financial condition were chosen and formulas determined. Issues 1 and 2 of the CAH Financial Indicators Report were mailed to the chief executive officers of 853 CAHs in the summer of 2004 and 1,092 CAHs in the summer of 2005, respectively. Each report included indicator values specifically for their CAH, indicator medians for peer groups, and an evaluation form. FINDINGS: Chief executive officers found the indicators to be useful and the underlying formulas to be appropriate. The multiple years of data provide snapshots of the industry as a whole, rather than trend data for a constant set of hospitals. CONCLUSIONS: The CAH Financial Indicators Report is a useful first step toward comparative financial indicators for CAHs.

The tissue distribution of the mRNA of ghrelin and subtypes of its receptor, GHS-R, in humans.

Ghrelin is a novel growth hormone-releasing peptide, originally identified in the rat stomach as the endogenous ligand for the growth hormone secretagogue-receptor (GHS-R1a). Ghrelin is involved in the regulation of GH release, but it has recently been suggested that ghrelin may have other actions, including effects on appetite, carbohydrate metabolism, heart, kidney, pancreas, gonads, and cell proliferation. The distribution of ghrelin, its functional receptor (type 1a) and the unspliced, non-functional GHS-R type 1b mRNA expression was investigated in various human tissues using classical and real-time reverse transcription and polymerase chain reaction. GHS-R1a was predominantly expressed in the pituitary and at much lower levels in the thyroid gland, pancreas, spleen, myocardium and adrenal gland. In contrast, ghrelin was found in the stomach, other parts of the gut and, indeed, in all the tissues studied (adrenal gland, atrium, breast, buccal mucosa, esophagus, Fallopian tube, fat tissue, gall bladder, human lymphocytes, ileum, kidney, left colon, liver, lung, lymph node, muscle, muscle, myocardium, ovary, pancreas, pituitary, placenta, prostate, right colon, skin, spleen, testis, thyroid, and vein). GHS-R1b expression was also widespread in all tissues studied. The significance of the widespread tissue distribution of ghrelin remains to be determined. These data suggest that ghrelin might have widespread physiological effects via different, partly unidentified, subtypes of the GHS-R in endocrine and non-endocrine tissues.