Sounding Out Pharmaceutical Processes

High-resolution ultrasonic spectroscopy is a novel technique with enormous potential for analysis of a wide range of samples and processes. This technique is based on precision measurements of velocity and attenuation of acoustical waves at high frequencies propagating through materials. It allows fast at/on line measurements analysis of formulation consistency (composition, structure) of raw materials, ingredients and intermediates, process impurity analysis, particle sizing, batch to batch variation, stability assessment etc in pharmaceutical industry. The technology can be used for static fingerprint measurements or for dynamic analysis of systems. Optical transparency is not required as ultrasonic waves propagate through opaque samples. The analysis is fast and non-destructive. High-resolution ultrasonic spectrometers were developed, patented and brought to the market by Ultrasonic Scientific Ltd. and recognised with various international awards. These instruments require small sample volumes, down to 0.03 ml, and give excellent resolution. They can be used for the analysis of composition, aggregation, particle sizing, gelation, micellisation, crystallisation, sedimentation, enzymatic activity, conformational transitions in polymers, biopolymer-ligand binding and antigen-antibody interactions, etc. This article describes main features of High-Resolution Ultrasonic Spectroscopy and area of applications of new high-resolution HR-US series of ultrasonic spectrometers. Several applications are illustrated including the monitoring of denaturation and aggregation of proteins in antibody solution, the measurements of the particle size in emulsions, precipitation in synthetic blood substitutes and crystallisation     

Application of adsorptive voltammetry to assess the stability of modified alanine aminotransferases

Alanine aminotransferase has been stabilized by using chemical modification with both bis(imidates) (of varying length) and succinic anhydride. The voltammetric behavior of the native enzyme and its various modified forms has been studied by using both cyclic voltammetry and differential pulse adsorptive voltammetry. A distinctive accumulation pattern was found for each of the stabilized enzymes at the static mercury drop electrode with respect to the native alanine aminotransferase. Adsorptive voltammetry was demonstrated to be a useful technique to assess the extent of chemical modification of this enzyme, which is indirectly related to their stability for use in biotechnological processes. The sue of differential pulse adsorptive voltammetry, after a preconcentration of the enzyme for 300 s at the electrode surface, has yielded a detection limit of 1.0 x 10(-9) M.     

Long-term validated simulation of a building integrated photovoltaic system

Electrical and thermal simulations of a building integrated photovoltaic system were undertaken with a transient system simulation program using real field input weather data. Predicted results were compared with actual measured data. A site dependent global-diffuse correlation is proposed. The best-tilted surface radiation model for estimating insolation on the inclined surface was selected by statistical tests. To predict the module temperature, a linear correlation equation is developed which relates the temperature difference between module and ambient to insolation. Different combinations of tilted surface radiation model, global-diffuse correlation model and predicted module temperature were used to carry out the simulation and corresponding simulated results compared with the measured data to determine the best combination which gave the least error. Results show that modification of global-diffuse correlation and module temperature prediction improved the overall accuracy of the simulation model. The monthly error between measured and predicted PV output was lied below 16%. Over the period of simulation, the monthly average error between measured and predicted PV output was estimated to be 6.79% whereas, the monthly average error between measured and predicted inverter output was 4.74%.     

Murine thymic lymphoma is associated with a species-specific hematopoietic progenitor cell subpopulation

Many strains of laboratory mouse are uniquely susceptible to the development of T cell lymphoma/leukemia, either spontaneously or as a result of chemical or radiation exposure. In contrast, T cell leukemias or lymphomas which are relatively uncommon in human populations, are not easily induced by radiation, and are not generally associated with chemotherapy or chemical exposure. Evidence is presented to suggest that differences in the susceptibility to the development of these malignancies is related to subtle but important variations in the regulation of hematopoietic stem cell differentiation between these two species.     

Clinical experience in temporomandibular joint arthroscopy

Clinical experience of arthroscopy in 12 temporomandibular joints with a clinical diagnosis of closed lock was described. There were 10 patients and all were females with a mean age of 31.2 years (range 20 to 59 years). The antero-lateral approach was used for entry into 11 joints. The clinical findings were adhesions (64%), fibrillation (64%), anterior displacement of disc (36%) and scuffing of the articular surface of the glenoid fossa (9%). Two of the joints that had arthrocentesis prior to arthroscopy did not show any different findings from the rest. Of the 8 patients who had pre-arthroscopy pain, 7 patients (88%) had reduction of the symptom. Three patients (38%) had complete resolution of pain. The range of mouth opening (measured as maximal incisor opening) increased in all patients two weeks following arthroscopy. The average change in maximal incisor opening was 40.3% with a range of 22% to 85%. The mean follow-up was 34 months (range 4 to 68 months).     

Right and left ventricular geometry and myocyte contractile processes with dilated cardiomyopathy: myocyte growth and beta-adrenergic responsiveness

OBJECTIVES: Comparison of the effects of supraventricular tachycardia-induced dilated cardiomyopathy on left and right ventricular isolated myocyte geometry and function. BACKGROUND: Chronic ventricular tachycardia and supraventricular tachycardia cause left ventricular dilation and dysfunction in humans. However, it is unknown whether supraventricular tachycardia-induced dilated cardiomyopathy is a homogenous process for both the left and right ventricles. METHODS: Dilated cardiomyopathy was induced by rapid atrial pacing (240 beats/min, 3 weeks) in 5 pigs. Five age- and weight-matched pigs served as controls. Ventricular mass was measured, myocyte dimensions were obtained, and isolated right and left ventricular myocyte contractile performance was evaluated at baseline and after beta-adrenergic receptor stimulation. RESULTS: With the development of dilated cardiomyopathy, there was no change in left ventricular mass. In contrast, right ventricular mass was increased, as was right ventricular myocyte cross-sectional area. In the control group, baseline right ventricular myocyte contractile function was increased compared to left ventricular myocytes. beta-adrenergic receptor stimulation increased myocyte contractile function in both left and right ventricular myocytes. With supraventricular tachycardia-induced cardiomyopathy, both left and right ventricular myocyte contractile function and beta-adrenergic responsiveness were reduced. CONCLUSIONS: This study demonstrated differences in left and right ventricular myocyte growth with supraventricular tachycardia-induced dilated cardiomyopathy and this differential growth response was associated with changes in contractile performance. Thus, in this model of cardiomyopathic disease, left and right ventricular growth and changes in contractile performance are not a homogenous process.