Evaluation of Combination Drug Therapy for Treatment of Antibiotic-Resistant Inhalation Anthrax in a Murine Model.

Bacillus anthracis is considered a likely agent to be used as a bioweapon, and the use of a strain resistant to the first-line antimicrobial treatments is a concern. We determined treatment efficacies against a ciprofloxacin-resistant strain of B. anthracis (Cipr Ames) in a murine inhalational anthrax model. Ten groups of 46 BALB/c mice were exposed by inhalation to 7 to 35 times the 50% lethal dose (LD50) of B. anthracis Cipr Ames spores. Commencing at 36 h postexposure, groups were administered intraperitoneal doses of sterile water for injections (SWI) and ciprofloxacin alone (control groups), or ciprofloxacin combined with two antimicrobials, including meropenem-linezolid, meropenem-clindamycin, meropenem-rifampin, meropenem-doxycycline, penicillin-linezolid, penicillin-doxycycline, rifampin-linezolid, and rifampin-clindamycin, at appropriate dosing intervals (6 or 12 h) for the respective antibiotics. Ten mice per group were treated for 14 days and observed until day 28. The remaining animals were euthanized every 6 to 12 h, and blood, lungs, and spleens were collected for lethal factor (LF) and/or bacterial load determinations. All combination groups showed significant survival over the SWI and ciprofloxacin controls: meropenem-linezolid (P = 0.004), meropenem-clindamycin (P = 0.005), meropenem-rifampin (P = 0.012), meropenem-doxycycline (P = 0.032), penicillin-doxycycline (P = 0.012), penicillin-linezolid (P = 0.026), rifampin-linezolid (P = 0.001), and rifampin-clindamycin (P = 0.032). In controls, blood, lung, and spleen bacterial counts increased to terminal endpoints. In combination treatment groups, blood and spleen bacterial counts showed low/no colonies after 24-h treatments. The LF fell below the detection limits for all combination groups yet remained elevated in control groups. Combinations with linezolid had the greatest inhibitory effect on mean LF levels.

Alterations in Cell Motility, Proliferation, and Metabolism in Novel Models of Acquired Temozolomide Resistant Glioblastoma.

Glioblastoma (GBM) is an aggressive and incurable tumor of the brain with limited treatment options. Current first-line standard of care is the DNA alkylating agent temozolomide (TMZ), but this treatment strategy adds only ~4 months to median survival due to the rapid development of resistance. While some mechanisms of TMZ resistance have been identified, they are not fully understood. There are few effective strategies to manage therapy resistant GBM, and we lack diverse preclinical models of acquired TMZ resistance in which to test therapeutic strategies on TMZ resistant GBM. In this study, we create and characterize two new GBM cell lines resistant to TMZ in vitro, based on the 8MGBA and 42MGBA cell lines. Analysis of the TMZ resistant (TMZres) variants in conjunction with their parental, sensitive cell lines shows that acquisition of TMZ resistance is accompanied by broad phenotypic changes, including increased proliferation, migration, chromosomal aberrations, and secretion of cytosolic lipids. Importantly, each TMZ resistant model captures a different facet of the "go" (8MGBA-TMZres) or "grow" (42MGBA-TMZres) hypothesis of GBM behavior. These in vitro model systems will be important additions to the available tools for investigators seeking to define molecular mechanisms of acquired TMZ resistance.

Acquisition of estrogen independence induces TOB1-related mechanisms supporting breast cancer cell proliferation.

Resistance to therapies targeting the estrogen pathway remains a challenge in the treatment of estrogen receptor-positive breast cancer. To address this challenge, a systems biology approach was used. A library of small interfering RNAs targeting an estrogen receptor (ER)- and aromatase-centered network identified 46 genes that are dispensable in estrogen-dependent MCF7 cells, but are selectively required for the survival of estrogen-independent MCF7-derived cells and multiple additional estrogen-independent breast cancer cell lines. Integration of this information identified a tumor suppressor gene TOB1 as a critical determinant of estrogen-independent ER-positive breast cell survival. Depletion of TOB1 selectively promoted G1 phase arrest and sensitivity to AKT and mammalian target of rapmycin (mTOR) inhibitors in estrogen-independent cells but not in estrogen-dependent cells. Phosphoproteomic profiles from reverse-phase protein array analysis supported by mRNA profiling identified a significant signaling network reprogramming by TOB1 that differed in estrogen-sensitive and estrogen-resistant cell lines. These data support a novel function for TOB1 in mediating survival of estrogen-independent breast cancers. These studies also provide evidence for combining TOB1 inhibition and AKT/mTOR inhibition as a therapeutic strategy, with potential translational significance for the management of patients with ER-positive breast cancers.

Functions of the adapter protein Cas: signal convergence and the determination of cellular responses.

Since Cas was first identified as a highly phosphorylated 130 kilodalton protein that associated with the v-Src and v-Crk-oncoproteins, considerable effort has been made to determine its function. Its predicted role as a scaffolding molecule based on its domain structure has been largely confirmed. Through its ability to undergo rapid changes in phosphorylation, subcellular localization and association with heterologous proteins, Cas may spatially and temporally regulate the function of its binding partners. Numerous proteins have been identified that bind to Cas in vitro and/or in vivo, but in only a few cases is there an understanding of how Cas may function in these protein complexes. To date, Cas-Crk and Cas-Src complexes have been most frequently implicated in Cas function, particularly in regards to processes involving regulation of the actin cytoskeleton and proliferation. These and other Cas protein complexes contribute to the critical role of Cas in cell adhesion, migration, proliferation and survival of normal cycling cells. However, under conditions in which these processes are deregulated, Cas appears to play a role in oncogenic transformation and perhaps metastasis. Therefore, in its capacity as an adapter protein, Cas serves as a point of convergence for many distinct signaling inputs, ultimately contributing to the generation of specific cellular responses.

Nutritional modulation of the cell cycle and breast cancer.

In the USA, breast cancer accounts for approximately 30% of all cancers diagnosed in women and is the second leading cause of cancer death in women. An understanding of the molecular genetic events governing breast cancer lead to both prevention and intervention strategies in an attempt to reduce mortality and morbidity from breast cancer. The last three decades of medical research examining the molecular pathogenesis of cancers have provided compelling evidence for the universal disruption of the cell cycle in human tumors. The importance of cell cycle control in human cancer was recognized by the recent award of the Nobel Prize to Drs Nurse and Hartwell for their discovery of the cyclins. More recent studies have demonstrated a critical interface between hormonal signaling and the cell cycle. In parallel, epidemiological studies have identified as being associated with breast cancer important dietary and environmental components that regulate hormonal signaling. This review describes the intersection of these two fields of study, which together imply a role for dietary prevention and intervention in human breast cancer perhaps through altering cell cycle components.

Reversal of exertional hypotension after coronary bypass grafting.

A decrease in systolic blood pressure that occurs with treadmill exercise testing may be a sign of reversible ischemic left ventricular dysfunction. To test this hypothesis, we examined retrospectively the postoperative treadmill responses of 37 patients who had exertional hypotension (end exercise systolic blood pressure less than or equal to initial preexercise levels) before coronary arterial bypass grafting. This group of 37 patients was characterized preoperatively by an abnormal exercise electrocardiogram (36 patients), multiple vessel occlusive disease (36 patients) and a normal ejection fraction at rest (32 patients). Postoperative exercise tests showed improvement in hemodynamic and electrocardiographic changes with reversal of exertional hypotension (33 patients), and conversion to a normal exercise electrocardiogram (29 patients). Coronary bypass surgery can be expected to reverse exertional hypotension in patients with symptomatic angina pectoris and evidence of ischemia in the exercise electrocardiogram.

Perioperative ischemic injury after coronary bypass graft surgery.

Two hundred twelve patients who underwent isolated coronary bypass graft surgery were prospectively evaluated for perioperative ischemic injury. All patients underwent preoperative and postoperative testing with technetium 99m pyrophosphate first-pass ventriculography combined with myocardial uptake scans, 12-lead electrocardiography, and serial creatinine phosphokinase MB determination. Fifteen percent of the patients had ischemic injury with at least two test results positive, but only 4 percent had positive results of all three tests. No single test proved adequate. Enzyme levels were highly sensitive and had value as a screening test. The electrocardiogram was specific but only moderately sensitive. The single best test was the radionuclide scan with good sensitivity and no false-positive results. All three tests are required to rigorously diagnose ischemic injury.

Healing of electrosurgical and scalpel wounds in rabbits.

Skin wounds in rabbits were tested after healing periods of up to three weeks to determine if scalpel wounds differed from those made electrosurgically. Tensile tests showed that the electrosurgical wounds were initially stronger, but at four days there was no difference. Thereafter the scalpel wounds were stronger and their healing progressed much faster. Histological preparations showed more extensive inflammation and necrosis in the electrosurgical wounds.

Scoliosis in chickens.

Scoliosis developed in 55 per cent of sexually mature birds (68 per cent of male and 46 per cent of female birds) in a highly inbred line of chickens originally produced from white Leghorns. The curve could first be detected at five to six weeks of age and progressed until spontaneous fusion of the thoracic vertebrae occurred. Studies of these chickens indicated that abnormalities of growth and development of the spine are not the primary cause of the scoliosis. Preliminary studies of the paravertebral musculature also indicated that simple muscle imbalance is not responsible for the curve. Initial studies of collagen extracted from the scoliotic line of chickens showed it to be more soluble than similar collagen extracted from white Leghorn controls.

Mechanical properties of the tibia from chickens with idiopathic scoliosis.

The tibia from six-week old chickens that develop idiopathic scoliosis were studied with stress relaxation experiments and torsional strength testing. Most parameters observed did not show any significant differences between tibias obtained from chickens with scoliosis and tibias from the control birds; however, the rate of stress relaxation of the tibia from the birds with scoliosis was minimally increased over the controls. There were no significant differences noted in ultimate torsional strength, maximum angular deformity or modulae of torsional rigidity of the tibias from scoliotic chickens when compared to tibias from control chickens.

Nutritional copper deficiency and penicillamine administration: some effects on bone collagen and arterial elastin crosslinking.

Nutritional copper deficiency effects marked changes in the crosslinking of collagen and elastin, presumably in relationship to copper's role as a cofactor for lysyl oxidase. Lysyl oxidase controls one of the initial steps in the crosslinking of elastin and collagen, i.e., the conversion of peptidyl lysine or hydroxylysine residues to peptidyl alpha-aminoadipic-delta-semialdehyde derivatives. Once lysine-derived aldehydic functions in collagen and elastin are formed, crosslinks occur via aldol and Schiff-base type condensations. A decrease in the degree of crosslinking results in changes in the biomechanical properties of both collagen- and elastin-rich tissues. Some of these changes are described with respect to chick bone and aorta. Likewise, penicillamine blocks crosslinking reactions. In this case, however, it is probably because of the formation of thiazolidine complexes between penicillamine aldehydic functions. The administration of penicillamine at different levels to young growing chicks allows the isolation of fibrous insoluble elastin varying in aldehyde content.

Sankofan socio-ethical reflections: the Tuskegee University National Bioethics Center's decade of operation, 1999-2009.

Primarily, this is a Sankofan socio-ethical analysis of the moral foundation of the Tuskegee University National Bioethics Center's decade of operation. The first section of the study will do the following: a) a Sankofan socio-ethical analysis of the Center's raison d'être; and b) definitions of ethical terms and the social world of the infamous syphilis study. The second section, as a result of the analysis, will address the Center's following challenges: c) the Center's challenge of theory and practice; d) the Center's challenge of moral heritage; and e) the Center's challenge of the future.