Human osteoblasts' proliferative responses to strain and 17beta-estradiol are mediated by the estrogen receptor and the receptor for insulin-like growth factor I.

The mechanism by which mechanical strain and estrogen stimulate bone cell proliferation was investigated using monolayer cultures of human osteoblastic TE85 cells and female human primary (first-passage) osteoblasts (fHOBs). Both cell types showed small but statistically significant dose-dependent increases in [3H]thymidine incorporation in response to 17beta-estradiol and to a single 10-minute period of uniaxial cyclic strain (1 Hz). In both cell types, the peak response to 17beta-estradiol occurred at 10(-8) - 10(-7) M and the peak response to strain occurred at 3500 microstrain ((mu)epsilon). Both strain-related and 17beta-estradiol-related increases in [3H]thymidine incorporation were abolished by the estrogen receptor (ER) modulator ICI 182,780 (10-8 M). Tamoxifen (10(-9) - 10(-8) M) increased [3H]thymidine incorporation in both cell types but had no effect on their response to strain. In TE85 cells, tamoxifen reduced the increase in [3H]thymidine incorporation associated with 17beta-estradiol to that of tamoxifen alone but had no such effect in fHOBs. In TE85 cells, strain increased medium concentrations of insulin-like growth factor (IGF) II but not IGF-I, whereas 17beta-estradiol increased medium concentrations of IGF-I but not IGF-II. Neutralizing monoclonal antibody (MNAb) to IGF-I (3 microg/ml) blocked the effects of 17beta-estradiol and exogenous truncated IGF-I (tIGF-I; 50 ng/ml) but not those of strain or tIGF-II (50 ng/ml). Neutralizing antibody to IGF-II (3 microg/ml) blocked the effects of strain and tIGF-II but not those of 17beta-estradiol or tIGF-I. MAb aIR-3 (100 ng/ml) to the IGF-I receptor blocked the effects on [3H]thymidine incorporation of strain, tIGF-II, 17beta-estradiol, and tIGF-I. HOBs and TE85 cells, act similarly to rat primary osteoblasts and ROS 17/2.8 cells in their dose-related proliferative responses to strain and 17beta-estradiol, both of which can be blocked by the ER modulator ICI 182,780. In TE85 cells (as in rat primaries and ROS 17/2.8 cells), the response to 17beta-estradiol is mediated by IGF-I, and the response to strain is mediated by IGF-II. Human cells differ from rat cells in that tamoxifen does not block their response to strain and reduces the response to 17beta-estradiol in TE85s but not primaries. In both human cell types (unlike rat cells) the effects of strain and IGF-II as well as estradiol and IGF-I can be blocked at the IGF-I receptor.     

Effects of Metal Exposures on Juvenile Clams,Mercenaria mercenaria

Bulletin of Environmental Contamination and Toxicology - Elevated metal concentrations occur throughout the coastal zone due to urbanization and various anthropogenic activities. The lethal...     

Intrapartum-related birth asphyxia in South Africa--lessons from the first national perinatal care survey.

BACKGROUND: The recent amalgamation of data by users of the Perinatal Problem Identification Programme (PPIP) throughout South Africa has culminated in the publication of the Saving Babies report. OBJECTIVES: To determine the absolute rate of death from intrapartum-related birth asphyxia, and the contribution of intrapartum-related asphyxia to total perinatal mortality in South African hospitals, and to identify the primary obstetric causes and avoidable factors for these deaths. METHODS: The amalgamated PPIP data for the year 2000 were obtained from 27 state hospitals (6 metropolitan, 12 town and 9 rural) in South Africa. In PPIP-based audit, all perinatal deaths are assigned primary obstetric causes and avoidable factors, and these elements were obtained for all deaths resulting from intrapartum-related birth asphyxia. RESULTS: There were 123,508 births in the hospitals surveyed, with 4,142 perinatal deaths among infants > or = 1,000 g, giving a perinatal mortality rate of 33.5/1,000 births. The perinatal mortality rate from intrapartum-related birth asphyxia was 4.8/1,000 births. The most frequent avoidable factors were delay by mothers in seeking attention during labour (36.6%), signs of fetal distress interpreted incorrectly (24.9%), inadequate fetal monitoring (18.0%) and no response to poor progress in labour (7.0%). The perinatal mortality rates for metropolitan, town, and rural areas were 30.0, 39.4 and 30.9/1,000 births respectively. The contribution of intrapartum-related birth asphyxia to perinatal mortality in these areas was 10.8%, 16.7% and 26.4% respectively. CONCLUSION: The high rates of perinatal death from intrapartum-related birth asphyxia in South Africa are typical of those in underdeveloped countries, with the most serious deficiencies in rural areas. Most of these deaths are avoidable and the reduction of these rates presents an important challenge to providers of perinatal care in this country. Areas worthy of research and action include provision of mothers' waiting facilities in rural regions, improvements in fetal monitoring, partogram-based labour management, and the establishment of midwifery staffing norms for South African labour units.     

Le syndrome de Lazare: une problématique de la rémission. Réflexions autour de la maladie cancéreuse chez l’adulte

Résumé: La rémission du cancer peut être l’occasion pour certains patients d’une réelle détresse émotionnelle ainsi que d’une désadaptation psychologique appelées: syndrome de Lazare. Nous émettons trois hypothèses explicatives quant à la survenue de tels troubles. La première confronte l’issue du cancer aux concepts psychanalytiques de dette et de masochisme. La deuxième envisage les symptômes sous l’angle d’une réaction de sevrage. Et la dernière évoque le contrecoup traumatique des traitements.Dossier: «Cliniques du cancer»     

The photoionization-reduced energy in LSC.

The atomic rearrangement cascade that follows the electron-capture decay process in low-Z radionuclides involves X-rays which have high photoelectric interaction probabilities. When the K-shell binding energy of the ionized atom (e.g., hydrogen) is significantly lower than the energy of the X-ray photon, the detector response to a photon-equivalent energy electron and the whole photoionization process are very similar. This is not the case when the scintillator cocktail contains larger atoms (e.g., oxygen and phosphorus in Ultima Gold). For larger Z atoms, the reduced energy of the whole photoionization process is less than the reduced energy of the interacting photon due to the nonlinear effects of ionization quenching. This paper shows the convenience of including a more detailed simulation of the photoionization process in the atomic rearrangement detection model for electron-capture nuclides such as (55)Fe, (51)Cr and (54)Mn. The need for more elaborate atomic rearrangement models is a consequence of the analysis of (125)I data.