Reproductive hormones and bone mineral density in women runners.

We examined the relationships among reproductive hormone concentrations and bone mineral density (BMD) in 43 women runners classified as eumenorrheic (n = 24), oligomenorrheic (n = 8), or amenorrheic (n = 11). Results were compared with a eumenorrheic nonrunner control group (n = 11). Serum 17 beta-estradiol, progesterone, and dehydroepiandrosterone sulfate concentrations were determined in daily blood samples for 21 days, and integrated concentrations (areas under the curve) were calculated. BMD was assessed at the lumbar spine and proximal femur by dual-photon absorptiometry. As expected, 17 beta-estradiol, progesterone, and lumbar spine BMD were higher in the control and eumenorrheic runner groups than in the oligomenorrheic and amenorrheic runner groups (P less than 0.05). Progesterone concentration was significantly correlated with lumbar spine BMD in the eumenorrheic runners (r = 0.61). None of the steroid hormones was significantly related to BMD in the oligomenorrheic/amenorrheic group. The present data suggest that circulating levels of gonadal steroid hormones affect axial BMD in eumenorrheic runners.     

Study of human erythrocyte membrane proteins by 2-dimensional electrophoresis

Fractionation of human erythrocyte membrane proteins was performed using a modification of two-dimensional gel electrophoresis described by P. O'Farrel with isoelectric point plotted against molecular mass. All major erythrocyte proteins, including high molecular weight proteins, such as spectrin and band 3 protein, identified by one-dimensional sodium dodecyl sulfate gel electrophoresis, were visualized by silver staining of two-dimensional gels. All in all about 50 polypeptides were distinguished on two-dimensional electrophoretic patterns. Preliminary protein map was developed.     

Reversing the detrimental effect of adriamycin on skin grafts in rats

We evaluated in a rat model the effects of a homologous fibrin glue in reversing the effects of Adriamycin on adherence and take of skin grafts. A total of 40 male Fisher rats were used in the study. During the first phase of the experiment, the animals were assigned to either group I (N = 10) receiving normal saline or group II (N = 10) receiving 6 mg/kg Adriamycin by tail vein injection 24 hours before surgery. Skin grafts with and without fibrin glue were placed over wounds in the backs of the animals and adherence was measured at 24 and 48 hours. In the second phase (N = 20), the experiment was repeated, this time evaluating the total area of skin graft take at 7 days. Fibrin glue was found to increase adherence and take of skin grafts in all Adriamycin-treated animals.     

Chemotactic assay for biological effects of silver nanoparticles

A method is proposed for assessing the biocidal efficacy of water-dispersed nanoparticles of silver. It is based on negative chemotaxis of the plasmodia of the slime mold Physarum polycephalum. Biocidal and repellent effects were compared for silver nanoparticles, Ag⁺ ions, and AOT in solution and in the agar gel. In such characteristics as increasing the period of auto-oscillations of contractile activity, decreasing the area of spreading on substrate, and substrate preference in spatial tests, silver nanoparticles proved to be substantially more effective than Ag⁺ and AOT. The lethal concentrations of the nanoparticles were close to those found earlier for bacteria and viruses. The chemotactic tests allow quantitative assessment of the biological reaction and monitoring its dynamics; in resolution, they are superior to the tests based on the lethal action of biocidal agents.     

1 of the pathways for normalization of populations of malignant cells

The paper reports reasons for a possibility of tumour regression due to selection of low-malignant and differentiating clones. Experimental evidence is provided supporting this view.     

Mitochondrial DNA polymorphism in Tuvinian population of reindeer Rangifer tarandus L.

Mitochondrial DNA variation was examined in one of the southem most populations of domestic reindeer, inhabiting Tyva Republic (Tuva). In Tuvinian population sequence polymorphism of the mitochondrial DNA D-loop region was demonstrated. In a sample of 29 individuals 7 mitotypes were distinguished, pointing to the preservation of rather high level of genetic diversity in this population.     

Late Glacial and Holocene environmental and climatic changes from a limnological transect through Colombia, northern South America

We present a synthesis of the palaeolimnological and palaeoclimatic reconstructions of four sites in Colombia. The record from Lake El Caimito, the westernmost site on the Pacific Coast, dates from the Late Holocene and shows lacustrine sedimentation frequently interrupted by fluvial pulses. These pulses probably reflect periods of increased precipitation related to La Niña phases. East of El Caimito site is the Patía swamp, situated between the Western and Central Andean Cordilleras. The Patía records the dynamics of forest expansion/reduction and changes in water levels. Although the climatic signal of the Patia core is difficult to reconstruct, there is a clear increase in humidity in the Mid-Holocene. The Fúquene Lake record, on the Eastern Andean Cordillera, records dry and cold conditions during the Late Pleistocene, very humid conditions for the early Mid-Holocene, and dry conditions during the mid-Late Holocene. Las Margaritas site, on the eastern savannas, records dry conditions during the Early Holocene and overall humid conditions for the Mid- and Late Holocene. Climate conditions from the Fuquene and Las Margaritas sites seem to reflect the Holocene movements of the Intertropical Convergence Zone (ITCZ); the latter site being more affected by humidity coming from the Amazon region.