Relation between the level of specific antitoxin in the blood and the degree of immunity to tetanus toxin in wilte mice immunized with adsorbed tetanus toxoid

Summary Levels of the specific antitoxin (AE) in blood and the immunity intensity against tetanus toxin (LD₅₀) were simultaneously studied on white mice immunized with the adsorbed tetanus toxic. The blood for the antitoxin determination was taken from the blood vessels of the tail (cut off): AE and LD₅₀ increased with an increase of the antigen dose, the growth rate of the latter being much greater. The ratio between the growth rates of AE and LD₅₀ changed in the course of the development of immunity.LD₅₀ being constant, AE level in the blood corresponded to the period elapsed after the antigen injection.Presented by Member of the Academy of Medical Sciences of the USSR, P. F. Zdrodovsky     

Geometry-invariant gradient refractive index lens: analytical ray tracing

A new class of gradient refractive index (GRIN) lens is introduced and analyzed. The interior iso-indicial contours mimic the external shape of the lens, which leads to an invariant geometry of the GRIN structure. The lens model employs a conventional surface representation using a coincoid of revolution with a higher-order aspheric term. This model has a unique feature, namely, it allows analytical paraxial ray tracing. The height and the angle of an arbitrary incident ray can be found inside the lens in a closed-form expression, which is used to calculate the main optical characteristics of the lens, including the optical power and third-order monochromatic aberration coefficients. Moreover, due to strong coupling of the external surface shape to the GRIN structure, the proposed GRIN lens is well suited for studying accommodation mechanism in the eye. To show the power of the model, several examples are given emphasizing the usefulness of the analytical solution. The presented geometry-invariant GRIN lens can be used for modeling and reconstructing the crystalline lens of the human eye and other types of eyes featuring a GRIN lens.     

Comparative Analysis of the Response of Microcirculation Parameters and Blood Pressure to Geomagnetic Activity in Healthy People

We analyze the results of daily laser Doppler flowmetry monitoring of blood microcirculation parameters in 9 healthy volunteers performed in 2006-2009. Dependence of microcirculation and BP parameters on geomagnetic activity was analyzed separately in each volunteer (the influence of ambient temperature was previously excluded). Significantly increased parameters of microcirculation in response to higher geomagnetic activity were found in 4 volunteers (44%) and elevated BP in 1 volunteer; in other cases, no reaction was detected. It was shown that individual sensitivity to geomagnetic activity is proportional to its mean level during the period of measurement. Since blood perfusion volume in tissues directly depends on peripheral vascular resistance, we can conclude that under conditions of high geomagnetic activity microvascular tone varies to a greater extent than the tone of major vessels.     

Comparative study of the effectiveness of Cozaar monotherapy and Cozaar and melatonin combined therapy in aged patients with hypertension

Effectiveness of Cozaar monotherapy (50 mg at 8 a.m.) was compared to that of Cozaar combination with melatonin (3 mg before sleep) in 21 patients with hypertension stage II (mean age 62 years). Clinical symptoms and hemodynamic parameters were evaluated with ECG and blood pressure monitoring. The findings were processed with statistical methods and Kosinor-analysis. Cozaar alone had moderate hypotensive and vasodilating effects, affected circadian rhythm of systolic and diastolic blood pressure, heart rate. Combination Cozaar + melatonin reduced blood pressure more noticeably, diminished cardiac output, energy consumption of the myocardium, normalized normal chronostructure of blood pressure and heart rate circadian rhythms.     

Determination of the number of active centers and of the propagation rate constant for ethylene polymerization on supported Ni-containing catalysts by using 14CO

Ethylene polymerization on supported Ni-containing catalysts was studied using ¹⁴CO as the inhibitor and as a label for determining the number of active centers (AC). The polymerization rate decreases sharply after introducing a mole ratio ¹⁴CO/Ni = 0.5 ÷ 1 and recovers after the removal of ¹⁴CO. The number of labels in the polymer and in the liquid phase (hexane) increases with the amount of ¹⁴CO introduced and with ¹⁴CO contact time (τ_co). In the absence of ethylene the number of labels in the polymer does not increase with τ_co and the number of labels in the liquid phase is essentially less than in the presence of ethylene. The rate of the label accumulation in the polymer during short contact times (τ_co = 5 min) is essentially higher than that during the following periods of time (τ_co = 5–135 min). Fast label accumulation occurs through first ¹⁴CO molecule insertion into the Ni-polymer bond, and the slower one through copolymerization of ¹⁴CO with ethylene, i.e. when the second and more ¹⁴CO molecules insert into the polymer chain. Catalyst activity and the number of AC (in the range of 1.5 to 6% of Ni content) decrease with polymerization time. For both catalysts the values of the propagation rate constant are maximum at short polymerization time (5 to 15 min) and equal to (3 ± 0.8) · 10³ L/(mol · s) at 65°C.     

Ammonium Salts Promote Functional Adaptation of Rat Erythrocytes on the Model of Forced Swimming

Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...     

Comparison of retinal image quality with spherical and customized aspheric intraocular lenses

We hypothesize that an intraocular lens (IOL) with higher-order aspheric surfaces customized for an individual eye provides improved retinal image quality, despite the misalignments that accompany cataract surgery. To test this hypothesis, ray-tracing eye models were used to investigate 10 designs of mono-focal single lens IOLs with rotationally symmetric spherical, aspheric, and customized surfaces. Retinal image quality of pseudo-phakic eyes using these IOLs together with individual variations in ocular and IOL parameters, are evaluated using a Monte Carlo analysis. We conclude that customized lenses should give improved retinal image quality despite the random errors resulting from IOL insertion.