Localization of estrogen receptor-alpha in human and rabbit skeletal tissues

Estrogen is essential for the development and maintenance of optimal bone mass in women and men, and acts through activation of estrogen receptors (ER). We have examined the pathways of estrogen action on the skeleton by seeking to localize the "classical" estrogen receptor, ER alpha, to particular cells to test the hypotheses that 1) estrogen directly influences growth plate chondrocytes; and 2) estrogen has a principal action on bone tissue via osteoblasts. ER alpha messenger ribonucleic acid (mRNA) was localized by in situ hybridization in human specimens from five males (11-15 yr old), two females (9 and 11 yr old), and three growing rabbits. In all of the human material examined, ER alpha mRNA was consistently identified in chondrocytes. In all of the rabbit tissue studied, ER alpha mRNA was localized in chondrocytes of the growth plate and the subarticular epiphyseal growth center. ER alpha mRNA signals were readily observed in both active osteoblasts and lining cells on trabecular surfaces of all samples. No clear evidence of positive staining was detectable in osteoclasts or osteocytes in either species. The distribution of ER alpha mRNA coincided with immunolocalization of the ER protein in the human specimens. These data suggest a direct action of estrogen on growth plate chondrocytes that may affect longitudinal growth and subsequent fusion of the growth plate and also on osteoblasts to affect bone formation at trabecular sites.     

Analytical approach to heterogeneity correction factor calculation for brachytherapy

In brachytherapy treatment planning, the effects of tissue and applicator heterogeneities are commonly neglected due to lack of accurate, general, and fast three-dimensional (3D) dose-computational algorithms. A novel approach, based on analytical calculation of scattered photon fluxes inside and around a disk-shaped heterogeneity, has been developed for use in the three-dimensional scatter-subtraction algorithm. Specifically, our model predicts the central-ray dose distribution for a collimated photon isotropic source or brachytherapy "minibeam" in the presence of a slab of heterogeneous material. The model accounts for the lateral dimensions, location, composition, density, and thickness of the heterogeneity using precalculated scatter-to-primary ratios (SPRs) for the corresponding homogeneous problem. The model is applicable to the entire brachytherapy energy range (25 to 662 keV) and to a broad range of materials having atomic numbers of 13 to 82, densities of 2.7 g.cm-3 (Al) to 21.45 g.cm-3 (Pt) and thicknesses up to 1 mean free path. For this range of heterogeneous materials, the heterogeneity correction factors (HCFs) vary from 0.09 to 0.75. The model underestimates HCF when multiple scattering prevails and overestimates HCF when absorption dominates. However, the analytic model agrees with Monte Carlo photon transport (MCPT) benchmark calculations within 1.8% to 10% for 125I, 169Yb, 192Ir, and 137Cs for a wide variety of materials, with the exception of Ag. For 125I shielded by Ag, where the mean discrepancy can exceed 25%, the error is due to K-edge characteristic x rays originating within the heterogeneity. The proposed approach provides reductions in CPU time required of 5 x 10(4)-10(5) and 100 in comparison with direct MCPT simulation and 1D numerical integration, respectively. The limitations of model applicability, as determined by the physical properties of heterogeneity material and accuracy required, are also discussed.     

Ultrasonographic signs of chromosome aberrations]

Factors predictive of psychiatric outcome in the second 6 months following traumatic brain injury (TBI) in 43 children and adolescents were assessed prospectively. The outcome measure was the presence of a psychiatric disorder not present before the injury ("novel"). Out of six models tested, four were predictive of novel psychiatric disorder: preinjury family function, family psychiatric history, socioeconomic class/intellectual function, and behavior/adaptive function. Post hoc analyses suggested that preinjury family functioning measured by a structured interview was a significant predictive variable. Severity of injury, when reclassified as severe versus mild/moderate TBI, significantly predicted novel psychiatric disorders. These data suggest that some children, identifiable through clinical assessment, are at increased risk for psychiatric disorders following TBI.     

Changes in skeletal metabolism in pubertal girls can be revealed by biochemical parameters of calcium metabolism and bone turnover

Biochemical changes related to skeletal turnover in puberty were investigated in a sample of 67 girls aged 8-14 years. The following biochemical parameters were measured in serum: total calcium, phosphate, magnesium, total alkaline phosphatase, osteocalcin, and calcium and hydroxyproline in the second morning urine. Thirty-five premenarchal girls (8-11 years) had significantly lower serum calcium, and higher alkaline phosphatase and phosphate than those menstruating regularly (N = 32, 12-14 years). A statistically significant negative correlation of serum parameters and age was found for phosphate and alkaline phosphatase in all subjects, and for calcium and magnesium only in the premenarchal girls. These results indicated the more intensive processes of skeletal metabolism occurring in prepubertal age and early puberty to reflect in basic biochemical parameters of calcium and bone metabolism. Analysis of correlation between biochemical parameters showed alkaline phosphatase and phosphate to correlate positively with hydroxyproline excretion and negatively with urinary calcium in all subjects. In the subjects after menarche, osteocalcin correlated with alkaline phosphatase and phosphate. Thus, biochemical parameters indirectly reflected physiologic changes occurring with bone turnover in puberty. Variations in bone turnover during puberty, including a more pronounced bone formation during prepubertal or early stages, can be indirectly observed through biochemical parameters related to calcium and bone metabolism. Investigations of skeletal growth and puberty would benefit from specific markers of bone remodeling and "basic" biochemical parameters, as it might disclose subtle metabolic relationships.     

Axial nonuniformities and flow in columns for capillary electrochromatography

Unlike in capillary zone electrophoresis and microscale high-performance liquid chromatography, columns in capillary electrochromatography (CEC) have discontinuities of the electric field strength and the flow velocity at the interface of the packed and open segments of the column. The goal of the present work is to offer a framework for measuring and interpreting the relevant electrochromatographic parameters such as the electric field strength, the potential drop, and the flow velocity in the packed segment of a CEC column. This would help us gain further insight in the electrochromatographic process and facilitate the design of CEC separation technology and comparison of data from different sources. First, the flow of ions that is governed by the conservation of current is analyzed and the potential drop across the packed and open segments of the column calculated. Then, conservation of volumetric flow rate is used to calculate the flow velocities through the two segments and, further, to estimate the net flow velocity through such a column. To satisfy the mass conservation law, in most cases a "flow-equalizing intersegmental pressure", which is different from the pressures at the two ends of the column, develops at the interface of the packed and the open segments. The intersegmental pressure, induced to equalize the flow rates in the two segments, has been shown to have a significant effect on the magnitude as well as the radial distribution of the flow velocity in the open segment, where the net flow becomes a mixture of electroosmotic and pressure-driven flows.     

Multiple organ insufficiency in destruction of soft tissues

The most important methodological problems of modern medicine, such as sociobiological relationships, the methodological and social aspects of teaching of normalcy, health, and diseases, physiological/pathological ratios, determinism, casualty and etiology, a part and the whole, regional and systemic in the light of the systems approach, diagnosis in the light of conception, etc. To solve these problems is inseparably linked with the assessment and analysis of general theoretic and methodological issues outlined in the "General Human Pathology" (the 2nd edition) by D. S. Sarkisov, M. A. Paltsev, and N. K. Khitrov (Moscow, 1997). The work is a peculiar unit of a paper and a review.     

A dynamic study of the intensity of mitogenesis in an osteoblast culture in the presence of ultrasonically dispersed hydroxyapatite

Ceramic hydroxyapatite is frequently used in clinical practice nowadays; it is applied in surgical interventions on facial skull bones. This biological material is used as bone substitute and bone connector, but many authors claim that it is devoid of osteoinductor properties. Research is in progress on the effects of a "cold", that is, biochemically active form of ceramic hydroxyapatite on proliferative activity of a number of cell populations. No mitogenesis stimulation was observed during incubation of hydroxyapatite with osteoblast culture; on the contrary, a reduction of proliferative processes intensity was observed. Remembering that hydroxyapatite is a surfactant we repeated this experiment under similar conditions but used a hydroxyapatite molbfication with specific activity increased by two orders in comparison with its close analogs. Mitogenesis intensity was assessed by radiometric method from 3H-thymidine incorporation. The data indicated stimulation of proliferative processes in osteoblast culture.     

Laser-modified aluminium surfaces with iron

Possible improvements in the mechanical properties of surface-coated aluminium have been investigated. Aluminium plasma sprayed with iron powder was processed using two different laser-beam settings (integrated and defocused) with varying processing parameters. Mechanical and microstructural characterizations of the specimens revealed great differences between the two laser-beam settings. The defocused laser beam showed a clear improvement of hardness which was not observed for the integrated laser beam. The integrated laser beam gave deep melt pools with large Al₃Fe particles (10–200 m) in the top layer, and smaller -Al (Fe, Mn)Si particles (0.1–0.3 m) throughout the melt pool. Small, partly coherent Al₃Fe precipitates (0.25 m long) were found between the large Al₃Fe particles. Processing with a defocused laser beam produced a shallower melt pool with a homogeneous distribution of the iron in the form of Al₃Fe particles.     

Evaluation of retail fresh meat packagings covered with stretch films of plasticized PVC and non‐PVC alternatives

The characteristics and performance of several non‐PVC stretch films were compared to those of plasticized PVC. Initially the main polymer components of the film were identified by infrared spectrometry and differential scanning calorimetry. The differences between films in mechanical properties, such as puncture resistance and tensile strength, varied about a factor of two, while the differences in elongation at break were considerably higher. Plasticized PVC showed properties somewhere in the middle. The water vapour transmission was highest for PVC, while its permeability to oxygen was the lowest. The potential for overall migration was assessed by substitute testing, using 95% ethanol and isooctane as test media, and the migration from PVC was found to be the highest. However, after use of the appropriate reduction factor of four, as allowed for fresh meat, the PVC film also proved to conform to legislation. The potential for specific migration was investigated by solvent extraction followed by gas chromatography. Twenty‐four components were identified, of which 11 could be compared to relevant migration limits based on evaluations of the EU Scientific Committee for Food. The release of solvents was estimated by direct thermal desorption at 100°C. Four films of different composition were used in a storage experiment with fresh beef. The meat quality was followed by measurements of colour, microbiological quality (total colony forming units and lactic acid bacteria) and lipid oxidation (thiobarbituric acid reactive substances) through a prolonged shelf‐life test. No differences in meat quality during normal shelf‐life were seen as a function of the film used. Copyright © 2004 John Wiley & Sons, Ltd.