Backwrd population projection by a generalized inverse

The Leslie population projection matrix may be used to project forward in time the age distribution or age-sex distribution of a population. As it is a singular matrix, it does not have an inverse, and so it is not clear that there is a corresponding procedure for backward projection. In terms of the eigenvalues and eigenvectors of the Leslie matrix, certain generalized inverses are constructed that can sometimes be used advantageously for backward projection.     

Xylene Poisoning: A Report on One Fatal Case and Two Cases of Recovery after Prolonged Unconsciousness

Three cases of xylene poisoning occurred after prolonged inhalation of paint fumes. Analysis showed that xylene comprised more than 90% of the solvent in the paint, the total solvent comprising 34% of the paint by weight. One patient was dead on admission, while the other two recovered after at least 15 hours'' loss of consciousness. Both patients had transient liver cell damage, and one temporary impairment of renal function.     

Expiratory flow limitation in dogs with regional changes in lung mechanical properties

We examined maximum expiratory flow (Vmax) in two canine preparations in which regional changes in lung mechanical properties were produced. In one experiment serial bronchial obstructions were made to determine whether flow-limiting sites (choke points, CP) would occur in series. With the right lung tied off, constrictions were placed at the left lower lobar bronchus (LLL) and left main-stem bronchus. On deflation from total lung capacity, the obstructed LLL and nonobstructed left upper lobe (LUL) emptied into the obstructed left main-stem bronchus. Although a CP common to both lobes was identified at the main-stem obstruction, which limited total Vmax, we questioned whether there was also a CP at the lobar obstruction that fixed LLL flow. In that case the rate of LLL emptying would not be dependent on the presence of the common (i.e., central) CP and thus the flow contribution of the LUL. We found that when the LUL was removed, the LLL increased its rate of emptying. Thus a lobar CP did not fix LLL flow and CP did not occur in series. In a second experiment emphysema was produced in the left lung to reduce lung recoil, whereas the right lung was normal. CP were identified at approximately lobar bronchi of each lung, and the lungs were emptied at different rates. A CP common to both lungs was not identified. Our results indicate that in localized lung disease, if flows from the different regions are high enough, then wave speed is reached in proximal airways, and a CP occurs centrally rather than peripherally. On the other hand, if flows are low, then wave speed is reached peripherally and a CP common to all lung regions does not occur.     

The sweet spot for biologics: recent advances in characterization of biotherapeutic glycoproteins

Introduction: Glycosylation is recognized as a Critical Quality Attribute for therapeutic glycoproteins such as monoclonal antibodies, fusion proteins and therapeutic replacement enzymes. Hence, efficient and quantitative glycan analysis techniques have been increasingly important for their discovery, development and quality control. The aim of this review is to highlight relevant and recent advances in analytical technologies for characterization of biotherapeutic glycoproteins.

Areas covered: The review gives an overview of the glycosylation trends of biotherapeutics approved in 2016 and 2017 by FDA. It describes current and novel analytical technologies for characterization of therapeutic glycoproteins and is explored in the context of released glycan, glycopeptide or intact glycoprotein analysis. Ultra performance liquid chromatography, mass spectrometry and capillary electrophoresis technologies are explored in this context.

Expert commentary: There is a need for the biopharmaceutical industry to incorporate novel state of the art analytical technologies into existing and new therapeutic glycoprotein workflows for safer and more efficient biotherapeutics and for the improvement of future biotherapeutic design. Additionally, at present, there is no ‘gold-standard’ approach to address all the regulatory requirements and as such this will involve the use of orthogonal glycoanalytical technologies with a view to gain diagnostic information about the therapeutic glycoprotein.     

Effect of high sucrose concentrations on mitochondria: Analysis of mitochondrial populations by density-gradient centrifugation after fixation with glutaraldehyde

It has been shown previously that intact rat liver mitochondria can be separated into two populations (designated B2 and B3) with mean buoyant densities of 1·184 and 1·216 respectively, by isopycnic sucrose density gradient centrifugation. A comparison has been made of some properties of these mitochondrial fractions from density gradients with non-fractionated mitochondria. Use was made of density gradient centrifugation for analysis of preparations fixed with appropriate concentrations of glutaraldehyde. The permeability of the membranes of non-fractionated mitochondria to sucrose was increased by exposure to hypoosmotic sucrose solutions. The B3 mitochondria differed from the non-fractionated mitochondria in their response to changes in osmotic pressure of the suspending medium while the B2 mitochondria showed essentially identical behaviour with the controls. However, under conditions of energized swelling the B2 mitochondria were markedly different to the controls. This difference, which is attributed to reduced permeability of the mitochondrial membranes to metabolites brought about by exposure to the high concentrations of sucrose encountered in the density gradient, was reversed by incubation in hypo-osmotic sucrose solutions in the presence of oxidizable substrate and permeant ions.Died December, 1969.