Association of Insulin Resistance and Higher Oncotype DX™ Recurrence Score

Annals of Surgical Oncology - Black women with breast cancer have a worse overall survival compared with White women; however, no difference in Oncotype DX? (ODX) recurrence scores has been...     

Production of mitogenic factor(s) by ovine corpora lutea throughout the estrous cycle.

To evaluate secretion of mitogenic factors by ovine corpora lutea (CL) at several stages of development, luteal explants from days 5 (n = 12 ewes), 10 (n = 6 ewes), and 15 (n = 6 ewes) of the estrous cycle were incubated in serum-free medium for 24 h. Luteal-conditioned media (LCM) were evaluated for their ability to stimulate proliferation of endothelial, BALB/3T3, and ovarian granulosa cells. After mitogenic activity of LCM from individual animals was evaluated, pools of LCM from each day of the estrous cycle were subjected to anion-exchange, cation-exchange, and heparin-affinity chromatography to characterize mitogenic activity. Pools of LCM also were utilized for ultrafiltration, heat-treatment, trypsin-treatment, and immunoneutralization studies. Results demonstrated that ovine CL secrete mitogenic activity that stimulates (P less than 0.01) proliferation of endothelial (135.7 +/- 5.3% of control) and granulosa cells (188.9 +/- 2.9%) but not 3T3 (103.2 +/- 2.5%) cells. Differences between stages of luteal development were not observed. The mitogenic activity bound to diethylaminoethyl-Sephacel and heparin-agarose, but not to carboxymethyl-Sepharose, indicating that ovine luteal mitogenic factor(s) is anionic and may belong to the heparin-binding growth factor (HBGF) family. In addition, the mitogenic activity was heat-labile, trypsin-sensitive, and appeared to have a M(r) greater than 100,000. Mitogenic activity for endothelial cells was partially neutralized with a specific antibody against HBGF-1 and was completely abolished with a specific antibody against HBGF-2. Moreover, HBGF-1 and HBGF-2 were immunolocalized in histological sections of CL from days 5 (n = 5 ewes), 10 (n = 5 ewes), and 15 (n = 5 ewes) after estrus. These findings are the first report of a major mitogenic factor(s) produced by cyclic ovine CL and indicate this factor is an HBGF-2-like molecule.     

Reservoir Competence of Vertebrate Hosts for Anaplasma phagocytophilum

Fourteen vertebrate species (10 mammals and 4 birds) were assessed for their ability to transmit Anaplasma phagocytophilum, the bacterium that causes human granulocytic anaplasmosis, to uninfected feeding ixodid ticks. Small mammals were most likely to infect ticks but all species assessed were capable of transmitting the bacterium, in contrast to previous findings.     

Increased cardiovascular disease risk indices in HIV-infected women

Little is known regarding cardiovascular disease risk indices in HIV-infected women. This study investigated cardiovascular disease risk indices in 100 consecutively recruited HIV-infected women and 75 healthy female control subjects. Subjects were recruited from hospital- and community-based health care providers. C-reactive protein (CRP), interleukin-6 (IL-6), adiponectin, lipid, and glucose levels were the main outcome measures. CT scan, dual-energy x-ray absorptiometry (DXA), and anthropometry were used to assess body composition. Although similar in age, weight, and racial composition, HIV-infected women demonstrated higher CRP (4.6 +/- 0.7 vs. 2.3 +/- 0.4 mg/L, P = 0.007), IL-6 (2.7 +/- 0.2 vs. 1.8 +/- 0.1 pg/mL, P = 0.02), triglyceride (1.84 +/- 0.21 vs. 0.85 +/- 0.05 mM, P = 0.0002), 2-hour glucose after oral glucose challenge (6.88 +/- 0.22 vs. 5.72 +/- 0.17 mM, P = 0.0003), and fasting insulin (81 +/- 8 vs. 45 +/- 2 pM, P = 0.0002) and lower high-density lipoprotein cholesterol (1.17 +/- 0.03 vs. 1.45 +/- 0.05 mM, P < 0.0001) and adiponectin (5.4 +/- 0.3 vs. 7.6 +/- 0.5 mg/L, P = 0.0001) levels compared with the control population. HIV-infected women had more abdominal visceral fat and less extremity fat by CT and DXA scan and demonstrated a higher waist-to-hip ratio (WHR) than the control population. Within the HIV group, CRP and other indices were significantly related to body composition in stepwise regression models. Among all subjects, WHR, but not HIV status, was significantly related to CRP and other cardiovascular disease risk indices. HIV-infected women demonstrate significantly increased risk factors for cardiovascular disease in association with abnormal fat distribution.     

Bayesian regression analysis of non-steady-state phenytoin concentrations: evaluation of predictive performance

Michaelis-Menten saturable pharmacokinetics confound the determination of appropriate phenytoin maintenance doses. This study retrospectively evaluated the performance of an IBM-PC/XT computer program applying Bayesian regression to the "explicit solution to the Michaelis-Menten equation." Zero to five non-steady-state phenytoin serum concentrations were used to predict either non-steady-state concentrations at least 10 days in the future (n = 49) or steady-state concentrations (n = 20). Non-steady-state concentration prediction precision (% mean absolute error) using 0-5 non-steady-state feedbacks was 137%, 62%, 39%, 31%, 25%, and 15%, respectively, and steady-state concentration prediction precision was 446%, 47%, 50%, 44%, 21%, and 13%, respectively. Elimination of subjects receiving concurrent drugs known to induce phenytoin metabolism significantly improved predictions based on population priors; however, performance improvements were not apparent after two serum level feedbacks. The program provided clinically acceptable predictions with four or more feedbacks. Refinement of population parameters and optimal sampling times should further improve performance.     

Iron accumulation during cellular senescence in human fibroblasts in vitro

Iron accumulates as a function of age in several tissues in vivo and is associated with the pathology of numerous age-related diseases. The molecular basis of this change may be due to a loss of iron homeostasis at the cellular level. Therefore, changes in iron content in primary human fibroblast cells (IMR-90) were studied in vitro as a model of cellular senescence. Total iron content increased exponentially during cellular senescence, resulting in 10-fold higher levels of iron compared with young cells. Low-dose hydrogen peroxide (H2O2) induced early senescence in IMR-90s and concomitantly accelerated iron accumulation. Furthermore, senescence-related and H2O2-stimulated iron accumulation was attenuated by N-tert-butylhydroxylamine (NtBHA), a mitochondrial antioxidant that delays senescence in vitro. However, SV40-transformed, immortalized IMR-90s showed no time-dependent changes in metal content in culture or when treated with H2O2 and/or NtBHA. These data indicate that iron accumulation occurs during normal cellular senescence in vitro. This accumulation of iron may contribute to the increased oxidative stress and cellular dysfunction seen in senescent cells.     

α-spectrins are major ubiquitinated proteins in rat hippocampal neurons and components of ubiquitinated inclusions in neurodegenerative disorders

We have demonstrated that α-spectrins (αSpIΣ* and αSpIIΣ1) are major ubiquitinated proteins in terminally differentiated hippocampal neurons in culture. Western blotting experiments, using αSpIΣ1, αSpIIΣ1, and ubiquitin antibodies and lysates of 11-day-old cultured rat hippocampal neurons, have demonstrated that a single band comigrating with αSpIΣ* and αSpIIΣ1 in a 5% polyacrylamide sodium dodecyl sulfate gel is recognized by ubiquitin antibodies when ¹²⁵I-protein A is used for detection. Immunofluorescence staining of the 7- and 12 -day-old rat hippocampal neuron cultures using ubiquitin, αSpIΣ1, and αSpIIΣ1 antibodies demonstrated that all of these antibodies label neurons but not the astrocytes in the cultures. Immunoprecipitation of spectrin subunits in lysates of 12-day-old rat hippocampal neurons under stringent conditions (9.5 M urea) using αSpIΣ1 and αSpIIΣ1 antibodies followed by Western blot experiments of the immunoprecipitated spectrin subunits using αSpIΣ1, αSpIIΣ1 and ubiquitin antibodies confirmed that both αSpIΣ* and αSpIIΣ1 are ubiquitinated in rat hippocampal neurons. Furthermore, we demonstrated by immunohistochemistry that α-spectrins are components of the cytoplasmic ubiquitinated inclusions in hippocampal neurons in Alzheimer’s and Parkinson’s disease patients.     

A connection between magnesium deficiency and aging: new insights from cellular studies

Most human cells can only replicate a limited number of times in cultures before they lose the ability to divide, a phenomenon known as replicative senescence, which seems to play a role in aging at the organismal level. Recent studies have shown that culture in low magnesium (Mg) accelerates the senescence of human endothelial cells and fibroblasts. Given the numerous critical roles of Mg, it seems likely that Mg inadequacy would interfere with cellular metabolism, which could affect the senescence process. Since i) several pieces of evidence link low Mg to aging and age-related diseases and ii) the Occidental diet is relatively deficient in Mg, we propose that broadly correcting nutritional intakes of Mg might contribute to healthier aging and the prevention of age-related diseases.