An Excel fitting routine for correcting protein absorption spectra for scatter.

Protein concentrations are often determined in a non-destructive manner by measuring the absorbance at 280 nm. However, light scattering in protein samples can complicate such assessment. We here describe a simple Excel Solver-based fitting routine to correct full protein UV absorption spectra for both Rayleigh and Mie scattering.

Engineering neurovascular organoids with 3D printed microfluidic chips.

The generation of tissue and organs requires close interaction with vasculature from the earliest moments of embryonic development. Tissue-specific organoids derived from pluripotent stem cells allow for the recapitulation of elements of embryonic development. However, they are not intrinsically vascularized, which poses a major challenge for their sustained growth, and for understanding the role of vasculature in fate specification and morphogenesis.

Cancer Stem Cells in Head and Neck Metastatic Malignant Melanoma Express Components of the Renin-Angiotensin System.

Components of the renin-angiotensin system (RAS) are expressed by cancer stem cells (CSCs) in many cancer types. We here investigated expression of the RAS by the CSC subpopulations in human head and neck metastatic malignant melanoma (HNmMM) tissue samples and HNmMM-derived primary cell lines. Immunohistochemical staining demonstrated expression of pro-renin receptor (PRR), angiotensin-converting enzyme (ACE), and angiotensin II receptor 2 (ATR) in all; renin in one; and ACE2 in none of the 20 HNmMM tissue samples.

Specificity-directed design of a FRET-quenched heptapeptide for assaying thermolysin-like proteases.

Thermolysin (TL) is an industrially important zinc endopeptidase, and the prototype of the M4 family of metallopeptidases. The catalytic function of TL and its relatives is typically assessed using chromogenic or more sensitive fluorescent peptides, with the latter substrates relying on Förster resonance energy transfer (FRET). Here, we demonstrate that a FRET-quenched heptapeptide designed on the basis of the enzyme's substrate specificity (Dabcyl-FKFLGKE-EDANS) is efficiently cleaved by TL and dispase (a TL-like protease) in between the Phe3 and Leu4 residues.

A novel magnet based 3D printed marker wand as basis for repeated in-shoe multi segment foot analysis: a proof of concept.

Background: Application of in-shoe multi-segment foot kinematic analyses currently faces a number of challenges, including: (i) the difficulty to apply regular markers onto the skin, (ii) the necessity for an adequate shoe which fits various foot morphologies and (iii) the need for adequate repeatability throughout a repeated measure condition. The aim of this study therefore was to design novel magnet based 3D printed markers for repeated in-shoe measurements while using accordingly adapted modified shoes for a specific multi-segment foot model.

Methods: Multi-segment foot kinematics of ten participants were recorded and kinematics of hindfoot, midfoot and forefoot were calculated.

Aquatic toxicity and abiotic thiol reactivity of aliphatic isothiocyanates: Effects of alkyl-size and -shape.

Aquatic toxicity data in the TETRATOX assay and reactivity data in an abiotic thiol assay were collected for a series of aliphatic isothiocyanates. These compounds can act as Michael-type acceptors with N-hydro-C-mercapto-addition to cellular thiols as a molecular mechanism of action. Comparison of both toxicity and reactivity among the analogues revealed that derivatives with a branch hydrocarbon moiety, especially branched in the β-position were less toxic and less reactive.

Molecular margin analysis predicts local recurrence after sublobar resection of lung cancer.

Sublobar resection for early-stage lung cancer has been used for patients who are not candidates for lobar resection. However, sublobar resection is associated with high local recurrence rates in the context of tumor-free parenchymal margins. The mechanism underlying this high recurrence rate is not well understood.

Gene expression alterations over large chromosomal regions in cancers include multiple genes unrelated to malignant progression.

In solid tumors, the relationship between DNA copy number and global expression over large chromosomal regions has not been systematically explored. We used a 12,626-gene expression array analysis of head and neck squamous cell carcinoma and normal oral mucosa and annotated gene expression levels to specific chromosomal loci. Expression alterations correlated with reported data using comparative genomic hybridization.

Progression of microsatellite instability from premalignant lesions to tumors of the head and neck.

The role of microsatellite alterations other than loss of heterozygosity (LOH) in the progression of benign epithelium to head-and-neck squamous cell cancer (HNSCC) has not been previously described. As the severity of the dysplasia increases at the microscopic level, there is an increase in the prevalence of LOH as defined by microsatellite analysis. Other alterations have been detected in the form of microsatellite instability (MSI), represented by insertions or deletions of base pairs.

Oncocytic neoplasms of the parotid gland: a 16-year institutional review.

Background: Oncocytic neoplasms of the parotid gland are a rare collection of salivary gland tumors that include oncocytosis, oncocytoma, and oncocytic carcinoma. Mounting evidence has linked the presence of oncocytes to acquired mitochondrial dysfunction.

Objectives: The study goals were to further delineate this poorly understood group of salivary gland tumors and to search for genetic alterations indicative of mitochondrial dysfunction.

Statistical analysis of signals from an intracavitary probe in a diseased heart.

A model study introduces the use of statistical signal processing to analyse the signals from an intracavitary probe. A complete derivation is given for the detection of one type of arrhythmogenic substrate, myocardial infarctions (MIs). Both the use of statistical signal processing and the detection of VT substrates, as opposed to activation maps, are unique.

Estimating defibrillation efficacy using combined upper limit of vulnerability and defibrillation testing.

It is frequently necessary, both clinically and in the laboratory, to estimate how strong a stimulus is required to defibrillate. Current techniques for forming such estimates require the repeated induction of ventricular fibrillation (VF) and subsequent attempts at defibrillation (DF testing). DF testing can be time consuming and in the operating room may increase the patient risks.

Reversal of jejunoileal bypass in patients with morbid obesity.

Jejunoileal bypass for morbid obesity was performed on 182 patients between 1971 and 1982. At 19 years' follow-up 60 (33 per cent) have had to undergo reversal. The compelling reasons for reversal were life-threatening malnutrition, immune complex disease, renal oxalate stones, osteomalacia and severe electrolyte disturbance.

Estimation of tissue resistivities from multiple-electrode impedance measurements.

In order to measure in vivo resistivity of tissues in the thorax, the possibility of combining anatomical data extracted from high-resolution images with multiple-electrode impedance measurements, a priori knowledge of the range of tissue resistivities, and a priori data on the instrumentation noise is assessed in this study. A statistically constrained minimum-mean-square error estimator (MIMSEE) that minimizes the effects of linearization errors and instrumentation noise is developed and compared to the conventional least-squares error estimator (LSEE). The MIMSEE requires a priori signal and noise information.

Comments on distinguishability in electrical impedance imaging.

In Electrical Impedance Imaging (EII), the spatial distribution of electrical resistivity of a volume conductor is reconstructed from measurements of potential which result from an externally applied electric field. The ability of such a system to distinguish a target inhomogeneity and the discussion of several measures of distinguishability has been a subject of a recent study. In this communication a few comments are added to those of.

A bidomain model with periodic intracellular junctions: a one-dimensional analysis.

The classical bidomain model of cardiac tissue views the intracellular and extracellular (interstitial) spaces as two coupled but separate continua. In the present study, the classical bidomain model has been extended by introducing a periodic conductivity in the intracellular space to represent the junctional discontinuity between abutting myocytes. In this model the junctional region of a myocyte is represented in a way that permits variation of junction size and conductivity profile.

Estimating the 95% effective defibrillation dose.

Minimum squared error (MinSE) testing protocols and a MinSE estimator are presented which accurately estimate the voltage that defibrillates 95% of the time (the ED95). The MinSE experimental procedures, presented in the form of lookup tables, detail the response to successful and unsuccessful trials. The lookup tables also show the ED95 estimates calculated from the observed results using the MinSE estimator.

Optical measurements of transmembrane potential changes during electric field stimulation of ventricular cells.

We evaluated transmembrane potential changes at the ends of isolated rabbit ventricular myocytes during defibrillation-strength shocks given in the cellular refractory period. The myocytes were stimulated (S1 pulse) to produce an action potential. Then a constant-field shock (S2 pulse) with an electric field of 20 or 40 V/cm was given at an S1-S2 interval of 50 msec.

A comparison of measured and calculated intracavitary potentials for electrical stimuli in the exposed dog heart.

The objective of this paper is to test the feasibility of using a multielectrode, intracavitary probe to solve a forward problem in which measured intracavitary potentials are compared to those calculated from subendocardial potentials and left ventricular (LV) cavity geometry. Intracavitary potentials and subendocardial potentials are measured simultaneously during electrical pacing stimuli from the LV apex, LV anterior base, LV posterior base, and right ventricular (RV) outflow tract of three exposed dog hearts. The LV cavity geometry is measured from postmortem magnetic resonance microscopy images of fixed hearts.

Calculating endocardial potentials from epicardial potentials measured during external stimulation.

This paper presents a boundary integral method for calculating the potential field generated by external stimulation at locations within the heart using realistic heart geometry and samples of the potential taken from the epicardial surface. This method assumes the heart is homogeneous and isotropic. To test the method we made epicardial and endocardial measurements in dogs during transthoracic pacing stimuli.

Assessing the effect of uncertainty in intracavitary electrode position on endocardial potential estimates.

The aim of this simulation study is to determine the effect of uncertainty in intracavitary probe electrode position on the accuracy of estimated endocardial potentials. Intracavitary probe position uncertainty is simulated by randomly moving an idealized probe surface about the center of an idealized left ventricular endocardial surface. These random deviations represent possible probe locations that are incorporated as correlated noise.

Acitretin : A Review of its Pharmacology and Therapeutic Use.

Synopsis: Acitretin (etretin), a second generation monoaromatic retinoid for use in the treatment of severe psoriasis and other dermatoses, is the major active metabolite of etretinate and possesses a similar therapeutic index; i.e. a similar ratio of clinical efficacy to adverse effects.

Acitretin. A review of its pharmacology and therapeutic use.

Acitretin (etretin), a second generation monoaromatic retinoid for use in the treatment of severe psoriasis and other dermatoses, is the major active metabolite of etretinate and possesses a similar therapeutic index; i.e. a similar ratio of clinical efficacy to adverse effects.

Rigid and flexible thin-film multielectrode arrays for transmural cardiac recording.

Thin-film transmural cardiac multielectric arrays were fabricated using integrated-circuit processing techniques. Several substantial improvements were achieved over conventional handmade arrays such as a smaller cross-sectional area, a larger number of recording sites per needle, more accurately controlled size and spacing of the recording sites, smaller bipolar spacings, and higher throughout yield. These advantages allow for a higher density of closely spaced bipolar electrodes capable of monitoring complex voltage and gradient fields present during ventricular fibrillation and defibrillation.