bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonhomologous End Joining Is Essential for Cellular Resistance to the Novel Antitumor Agent, β-Lapachone
Authors: Bentle Melissa S. , Reinicke Kathryn E. , Dong Ying , Bey Erik A. , Boothman David A.
Published: July 2007

Commonly used antitumor agents, such as DNA topoisomerase I/II poisons, kill cancer cells by creating nonrepairable DNA double-strand breaks (DSBs). To repair DSBs, error-free homologous recombination (HR), and/or error-prone nonhomologous end joining (NHEJ) are activated. These processes involve the phosphatidylinositol 3′-kinase–related kinase family of serine/threonine enzymes: ataxia telangiectasia mutated (ATM), ATM- and Rad3-related for HR, and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) for NHEJ. Alterations in these repair processes can cause drug/radiation resistance and increased genomic instability. β-Lapachone (β-lap; also known as ARQ 501), currently in phase II clinical trials for the treatment of pancreatic cancer, causes a novel caspase- and p53-independent cell death in cancer cells overexpressing NAD(P)H:quinone oxidoreductase-1 (NQO1). NQO1 catalyzes a futile oxidoreduction of β-lap leading to reactive oxygen species generation, DNA breaks, γ-H2AX foci formation, and hyperactivation of poly(ADP-ribose) polymerase-1, which is required for cell death. Here, we report that β-lap exposure results in NQO1-dependent activation of the MRE11-Rad50-Nbs-1 complex. In addition, ATM serine 1981, DNA-PKcs threonine 2609, and Chk1 serine 345 phosphorylation were noted; indicative of simultaneous HR and NHEJ activation. However, inhibition of NHEJ, but not HR, by genetic or chemical means potentiated β-lap lethality. These studies give insight into the mechanism by which β-lap radiosensitizes cancer cells and suggest that NHEJ is a potent target for enhancing the therapeutic efficacy of β-lap alone or in combination with other agents in cancer cells that express elevated NQO1 levels. [Cancer Res 2007;67(14):6936–45]
Hypoxia Enhances the Phosphorylation and Cytotoxicity of Ganciclovir and Zidovudine in Kaposi's Sarcoma-Associated Herpesvirus–Infected Cells
Authors: Davis David A. , Singer Kathleen E. , Reynolds Irene P. , Haque Muzammel , Yarchoan Robert
Published: July 2007

Primary effusion lymphoma (PEL) is a rare B-cell lymphoma caused by Kaposi's sarcoma-associated herpesvirus (KSHV). PEL is poorly responsive to standard cytotoxic chemotherapy and portends a poor survival. Consequently, new effective treatment options are urgently needed. It is known that KSHV encodes two lytic genes, ORF36 (phosphotransferase) and KSHV ORF21 (thymidine kinase), which can phosphorylate ganciclovir and azidothymidine, respectively. Here, we have explored whether these genes can be used as therapeutic targets for PEL. PEL arises in pleural spaces and other effusions that provide a hypoxic environment. Based on Northern blot analysis, exposure of PEL cells to hypoxia up-regulated the expression of both ORF36 and ORF21. Using a newly developed nonradioactive reverse-phase high-performance liquid chromatography/mass spectrometry method to separate and quantify the phosphorylated forms of ganciclovir and azidothymidine, we found that PEL cells exposed to hypoxia produced increased amounts of the toxic triphosphates of these drugs. Moreover, we found that hypoxia increased the cell toxicity of ganciclovir and azidothymidine in PEL cells but had no significant effect on the herpesvirus-negative cell line CA46. These findings may have clinical applicability in the development of effective therapies for PEL or other KSHV-related malignancies. [Cancer Res 2007;67(14):7003–10]
Interleukin-8 Is a Molecular Determinant of Androgen Independence and Progression in Prostate Cancer
Authors: Araki Shinako , Omori Yohei , Lyn Dominic , Singh Rajendra K. , Meinbach David M. , Sandman Yekutiel , Lokeshwar Vinata B. , Lokeshwar Bal L.
Published: July 2007

The proinflammatory chemokine interleukin-8 (IL-8) is undetectable in androgen-responsive prostate cancer cells (e.g., LNCaP and LAPC-4), but it is highly expressed in androgen-independent metastatic cells, such as PC-3. In this report, we show IL-8 functions in androgen independence, chemoresistance, tumor growth, and angiogenesis. We stably transfected LNCaP and LAPC-4 cells with IL-8 cDNA and selected IL-8–secreting (IL8-S) transfectants. The IL8-S transfectants that secreted IL-8 at levels similar to that secreted by PC-3 cells (100–170 ng/106 cells) were characterized. Continuous or transient exposure of LNCaP and LAPC-4 cells to IL-8 reduced their dependence on androgen for growth and decreased sensitivity (>3.5×) to an antiandrogen. IL-8–induced cell proliferation was mediated through CXCR1 and was independent of androgen receptor (AR). Quantitative PCR, immunoblotting, and transfection studies showed that IL8-S cells or IL-8–treated LAPC-4 cells exhibit a 2- to 3-fold reduction in PSA and AR levels, when compared with vector transfectants. IL8-S cells expressed 2- to 3-fold higher levels of phospho-EGFR, src, Akt, and nuclear factor κB (NF-κB) and showed increased survival when treated with docetaxel. This increase was blocked by NF-κB and src inhibitors, but not by an Akt inhibitor. IL8-S transfectants displayed a 3- to 5-fold increased motility, invasion, matrix metalloproteinase-9 and vascular endothelial growth factor production. LNCaP IL8-S cells grew rapidly as tumors, with increased microvessel density and abnormal tumor vasculature when compared with the tumors derived from their vector-transfected counterparts. Therefore, IL-8 is a molecular determinant of androgen-independent prostate cancer growth and progression. [Cancer Res 2007;67(14):6854–62]
Pten Inactivation and the Emergence of Androgen-Independent Prostate Cancer
Authors: Shen Michael M. , Abate-Shen Cory
Published: July 2007

Hormone refractory disease represents a late-stage and generally lethal event in prostate tumorigenesis. Analyses of mouse models have recently shown that the onset of hormone independence can be uncoupled from disease progression and is associated with activation of the phosphoinositide-3 kinase/Akt as well as Erk mitogen-activated protein kinase signaling pathways in the prostate epithelium, which act in part to counterbalance the inhibitory effects of androgen receptor signaling in the prostate stroma. These observations have potential implications for the treatment of patients with hormone refractory cancer and highlight the role of epithelial-stromal interactions for androgen independence. [Cancer Res 2007;67(14):6535–8]
A Secreted Isoform of ErbB3 Promotes Osteonectin Expression in Bone and Enhances the Invasiveness of Prostate Cancer Cells
Authors: Chen Nanyue , Ye Xiang-Cang , Chu Khoi , Navone Nora M. , Sage E. Helene , Yu-Lee Li-Yuan , Logothetis Christopher J. , Lin Sue-Hwa
Published: July 2007

The propensity for prostate cancer to metastasize to bone led us and others to propose that bidirectional interactions between prostate cancer cells and bone are critical for the preferential metastasis of prostate cancer to bone. We identified previously a secreted isoform of ErbB3 (p45-sErbB3) in bone marrow supernatant samples from men with prostate cancer and bone metastasis and showed by immunohistochemical analysis of human tissue specimens that p45-sErbB3 was highly expressed in metastatic prostate cancer cells in bone. Here, we show that p45-sErbB3 stimulated mouse calvaria to secrete factors that increased the invasiveness of prostate cancer cells in a Boyden chamber invasion assay. Using gene array analysis to identify p45-sErbB3–responsive genes, we found that p45-sErbB3 up-regulated the expression of osteonectin/SPARC, biglycan, and type I collagen in calvaria. We further show that recombinant osteonectin increased the invasiveness of PC-3 cells, whereas osteonectin-neutralizing antibodies blocked this p45-sErbB3–induced invasiveness. These results indicate that p45-sErbB3 enhances the invasiveness of PC-3 cells in part by stimulating the secretion of osteonectin by bone. Thus, p45-sErbB3 may mediate the bidirectional interactions between prostate cancer cells and bone via osteonectin. [Cancer Res 2007;67(14):6544–8]
Disruption of Nitric Oxide Synthase 3 Protects Against the Cardiac Injury, Dysfunction, and Mortality Induced by Doxorubicin
Authors: Neilan Tomas G. , Blake Sarah L. , Ichinose Fumito , Raher Michael J. , Buys Emmanuel S. , Jassal Davinder S. , Furutani Elissa , Perez-Sanz Teresa Miriam , Graveline Amanda , Janssens Stefan P. , Picard Michael H. , Scherrer-Crosbie Marielle , Bloch Kenneth D.
Published: July 2007

Background—Flavoprotein reductases are involved in the generation of reactive oxygen species by doxorubicin. The objective of the present study was to determine whether or not one flavoprotein reductase, endothelial nitric oxide synthase (nitric oxide synthase 3 [NOS3]), contributes to the cardiac dysfunction and injury seen after the administration of doxorubicin.

Methods and Results—A single dose of doxorubicin (20 mg/kg) was administered to wild-type (WT) mice, NOS3-deficient mice (NOS3−/−), and mice with cardiomyocyte-specific overexpression of NOS3 (NOS3-TG). Cardiac function was assessed after 5 days with the use of echocardiography. Doxorubicin decreased left ventricular fractional shortening from 57±2% to 47±1% (P<0.001) in WT mice. Compared with WT mice, fractional shortening was greater in NOS3−/−and less in NOS3-TG after doxorubicin (55±1% and 35±2%;P<0.001 for both). Cardiac tissue was harvested from additional mice at 24 hours after doxorubicin administration for measurement of cell death and reactive oxygen species production. Doxorubicin induced cardiac cell death and reactive oxygen species production in WT mice, effects that were attenuated in NOS3−/−and were more marked in NOS3-TG mice. Finally, WT and NOS3−/−mice were treated with a lower dose of doxorubicin (4 mg/kg) administered weekly over 5 weeks. Sixteen weeks after beginning doxorubicin treatment, fractional shortening was greater in NOS3−/−than in WT mice (45±2% versus 28±1%;P<0.001), and mortality was reduced (7% versus 60%;P<0.001).

Conclusions—These findings implicate NOS3 as a key mediator in the development of left ventricular dysfunction after administration of doxorubicin.
Sleep Duration and Hypertension Are Not Associated in the Elderly
Authors: van den Berg Julia F. , Tulen Joke H.M. , Neven Arie Knuistingh , Hofman Albert , Miedema Henk M.E. , Witteman Jacqueline C.M. , Tiemeier Henning
Published: July 2007

Several large studies have shown that both short and long average sleep durations increase the risk of hypertension in adults. We investigated whether sleep duration is also associated with hypertension in the elderly. This cross-sectional study was conducted in 5058 participants of the population-based Rotterdam Study, aged 58 to 98 years. Blood pressure was measured at the research center. Hypertension was defined as a systolic blood pressure of ≥160 mm Hg and/or a diastolic blood pressure of ≥100 mm Hg or current use of antihypertensive medication. In all of the participants, sleep duration was assessed by self-report. In a subsample of 975 subjects, it was additionally measured with actigraphy, a validated method that infers wakefulness and sleep from the presence or absence of limb movement. After adjustment for age and gender and additionally for body mass index, smoking, depressive symptoms, sleep medication use, diabetes mellitus, myocardial infarction, and stroke, none of the odds ratios (varying from 0.54; 95% CI: 0.27 to 1.08; to 1.19; 95% CI: 0.89 to 1.58) reflected a significant association between sleep duration and hypertension, whether measured by self-report or actigraphy. This study strongly suggests that sleep duration is not associated with hypertension in the elderly.
Comparison of the Efficacy of Morning Versus Evening Administration of Telmisartan in Essential Hypertension
Authors: Hermida Ramón C. , Ayala Diana E. , Fernández José R. , Calvo Carlos
Published: July 2007

Valsartan administration at bedtime as opposed to on wakening improves the sleep time–relative blood pressure decline toward a more dipper pattern without loss in 24-hour efficacy. Yet to be determined is whether this administration time-dependent efficacy is a class-related feature, characteristic of all angiotensin receptor blockers or specific only to valsartan. Terminal half-life is a major difference between angiotensin receptor blockers, being largest (≈24 hours) for telmisartan. This trial investigated the administration time-dependent antihypertensive efficacy of telmisartan. We studied 215 patients with hypertension (114 men and 101 women), 46.4±12.0 years of age, randomly assigned to receive telmisartan (80 mg/d) as a monotherapy either on awakening or at bedtime. Blood pressure was measured for 48 hours before and after 12 weeks of treatment. The significant blood pressure reduction after treatment was similar for both groups. Bedtime administration of telmisartan, however, was more efficient than morning dosing in reducing the nocturnal blood pressure mean. The sleep time–relative blood pressure decline was slightly reduced after telmisartan on awakening but significantly increased with bedtime dosing, thus reducing the prevalence of nondipping from baseline by 76%. Telmisartan administered at bedtime, as opposed to morning dosing, improved the sleep time–relative blood pressure decline toward a more dipper pattern without loss in 24-hour efficacy. Nocturnal BP regulation is significantly better achieved with bedtime dosing of telmisartan. Results from this prospective trial suggest that these beneficial features of bedtime dosing may be class related for angiotensin receptor blockers. These results should be taken into account when prescribing this class of antihypertensive medication for treatment of essential hypertension.
Hemostatic Abnormalities in Patients With Severe Preeclampsia
Authors: Heilmann Lothar , Rath Werner , Pollow Kunhard
Published: July 2007

Preeclampsia is the most common medical disorder of pregnancy. Early onset preeclampsia is defined as presentation of hypertension and proteinuria before 34 weeks of gestation. Alterations of endothelial cells and fibrin deposition in microvasculature lead to enhanced activation of the coagulation cascade and impaired fibrinolysis associated with multiple organ dysfunctions. Plasma samples were obtained from 50 patients with severe preeclampsia before 34 weeks of gestation and in 61 patients with late preeclampsia. Factor VIIIR:Ag, fibrinogen, D-dimer, and thrombomodulin increased with advanced pregnancy. The platelet count is very important because of the close correlation with the activations parameters of D-dimer and antithrombin. Our results were consistent with activated coagulation and lowering of platelet count in severe cases with early onset preeclampsia. Women who develop early onset preeclampsia characterized a subgroup of patients with more and severe hematologic abnormalities than women with late preeclampsia (after 34 weeks of gestation).
Pulmonary and Cardiac Involvement in Behçet Disease: 3 Case Reports
Authors: Yakut Zeynep Ilerisoy , Odev Kemal
Published: July 2007

Pulmonary and cardiac involvement in Behçet disease is rare but can cause life-threatening complications. This report presents computed tomography and magnetic resonance angiography findings in 3 patients with Behçet disease. Imaging findings were confirmed by surgery in 1 patient and by angiography in another. One patient had bilateral pulmonary artery aneurysms, 1 of which had already ruptured and had thrombosed. The other had unilateral pulmonary artery aneurysm and thrombosis accompanied with intracardiac thrombus formation. The third patient had unilateral pulmonary artery aneurysm, thrombus, and coronary artery aneurysm. As in our case, there have been rare reports of coronary artery disease and intracardiac thrombus formation associated with pulmonary vascular involvement. Noninvasive imaging modalities minimize any risk of endothelial damage and can be an alternative to angiography in assessment of pulmonary and cardiac involvement in Behçet disease.
Low-Intensity Oral Anticoagulant Plus Low-Dose Aspirin During the First Six Months Versus Standard-Intensity Oral Anticoagulant Therapy After Mechanical Heart Valve Replacement: A Pilot Study of Low-Intensity Warfarin and Aspirin in Cardiac Prostheses (LIWACAP)
Authors: Pengo Vittorio , Palareti Gualtiero , Cucchini Umberto , Molinatti Maurizio , Del Bono Roberto , Baudo Franco , Ghirarduzzi Angelo , Pegoraro Cinzia , Iliceto Sabino
Published: July 2007

The objective of this study was to evaluate the safety and efficacy of low-intensity warfarin treatment plus aspirin during the first 6 months after surgery in patients undergoing heart valve substitution with mechanical prostheses. Vitamin K antagonists (VKA) are able to reduce but not eliminate thrombosis and systemic embolism in patients with mechanical heart valves. The intensity of treatment and additional use of aspirin in these patients is still controversial. Consecutive patients undergoing aortic or mitral valve replacement (or a combination of the two) with mechanical prostheses were invited to participate in the study. After stratifying for site of prosthesis, patients were randomized to receive low intensity VKA treatment (target INR 2.5) plus aspirin (100 mg/day) for the first six months (Group A) or standard-intensity (INR target 3.7) VKA treatment (Group B). Mean follow-up was 1.5 years. Principal outcome events were systemic embolism, major bleeding, and vascular death. A total of 94 patients in Group A and 104 in Group B were randomized and followed up for 144 and 163 patient years, respectively. There were 5 (5%) events in Group A (4 major bleeding events and 1 vascular death) and 4 (4%) in group B (2 major bleeding events and 2 ischemic stroke). All the events except 1 occurred within the first 6 months after surgery. Cumulative incidence of primary outcome events was 5.8% (95% CI 0.9 to 10.7) in Group A and 4.3% (95% CI 0,2 to 8.4) in Group B (p=0.6). Low-intensity treatment plus aspirin during the first six months after surgery appears to be as effective and safe as moderate-high-intensity anticoagulation.
A Case of Hemophagocytic Lymphohistiocytosis After the Primary Epstein-Barr Virus Infection
Authors: Kitazawa Yasuhide , Saito Fukuki , Nomura Shosaku , Ishii Kazuyoshi , Kadota Eiji
Published: July 2007

The Epstein-Barr virus (EBV) infection is known to result in infectious mononucleosis, hemophagocytic syndrome, chronic active EBV infection, and lymphoma. Among them, hemophagocytic syndrome sometimes causes thrombocytopenia, which is often life threatening because of its hemorrhagic complications such as gastrointestinal bleeding and pulmonary alveolar hemorrhage. A young adult case of critical hemophagocytic syndrome after primary EBV infection is presented. Chemotherapy was performed using methyl prednisolone succinate, prednisolone, cyclosporin A, and 20 mg/kg of cyclophosphamide. The patient received intensive care, including plasma exchange for hepatic failure, extracorporeal membrane oxygenation for acute respiratory failure, and splenectomy for hemophagocytosis; however, the patient died of multiple organ failure, including fulminant hepatic failure. The pathologic examination of the resected specimen demonstrated infiltrated macrophages containing many phagocytosed erythrocytes. Further immunopathologic examination of these cells showed that the histiocyte markers were positive, whereas the T-cell marker was negative. In view of these findings, definite diagnosis of EBVrelated hemophagocytic lymphohistiocytosis could not be made at that time. The immunohistologic examinations on the liver necropsy specimen provided the evidences suggesting the morbid activation of the hepatic stellate macrophage by EBV-infected T/NK cells and subsequent apoptosis induction of the liver cells through the Fas ligand pathway.
State of the Art Reviews: Nonpharmacologic Approaches for the Treatment of Insomnia
Authors: Lynch Ann M. , Jarvis Courtney I. , DeBellis Ronald J. , Morin Anna K.
Published: July 2007

Insomnia is a common condition resulting in significant clinical and economic consequences. This review discusses the efficacy of nonpharmacologic treatment options commonly recommended for sleep onset and sleep maintenance insomnia. In addition, the efficacy of these approaches as part of a multifaceted intervention and in comparison to that of pharmacologic options is reviewed. The primary literature and review articles on the nonpharmacologic treatment of insomnia were identified through a MEDLINE search between 1966 and August 2006. Articles on the nonpharmacologic treatment of primary insomnia, including clinical trials on the efficacy of individual and combination treatment options, were reviewed. The nonpharmacologic treatment options for insomnia include stimulus control, sleep hygiene educations, sleep restriction, paradoxical intention, relaxation therapy, biofeedback, and cognitive-behavioral therapy. These treatment strategies produce significant changes in several sleep parameters of chronic insomniacs, including sleep-onset latency, wake time after sleep onset, sleep duration, and sleep quality. Many therapeutic options are available to treat insomnia, including nonpharmacologic strategies. Treatment recommendations, both pharmacologic and nonpharmacologic, should be made based on patient-specific insomnia symptoms, treatment history, and medical history.
Physical Activity: Physical Activity in the Management of Osteoarthritis of the Knee and Hip
Authors: Zoeller Robert F.
Published: July 2007

Symptomatic osteoarthritis (OA) affects more than 4 million adults in this country and is associated with joint degeneration, chronic pain, muscle atrophy, decreased mobility, poor balance, and physical disability. The prevalence of comorbid conditions such as heart disease, hypertension, and obesity is greater in those with symptomatic OA. Obesity is a risk factor for OA, and weight loss has been shown to reduce pain and improve physical function. The role of physical activity/inactivity in the development of OA is not clear. Limited evidence suggests that a sedentary lifestyle may increase the risk for OA, while high levels of physical activity have also been suggested to contribute to the development of OA. Regular aerobic exercise may moderate the functional decline associated with OA. Both aerobic and strength training have been reported to reduce pain and improve physical function in persons with knee and hip OA, although very few studies have specifically examined the effects of regular physical activity on the OA hip. While it is generally recommended that exercise programs for OA incorporate both aerobic and strength-training activities, no studies have been performed to evaluate the efficacy of combining these 2 modes of exercise compared with either alone. Little work has been done to determine the optimal exercise program for individuals with OA. One study suggests that exercise interventions should be performed a minimum of 3 days per week for a duration of at least 35 minutes. Exercise programs should be individualized based on the patient's preferences, abilities, limitations, and comorbidities. It is recommended that exercise programs for OA incorporate strategies designed to promote adherence. Home-based exercise appears to be as effective as supervised exercise programs.
Clinician's Corner: Osteoarthritis: A Lifestyle Medicine Assessment of Risks, Prevention, and Treatment
Authors: Greenstone Clinton L.
Published: July 2007

The prevalence of symptomatic osteoarthritis after the age of 55 years ranges from about 30% to 50% in men and 40% to 60% in women. With the increasing age of the population, it is estimated that in 20 years, osteoarthritis will be the fourth leading cause of disability in this country. Risk factors for osteoarthritis include previous knee surgery, occupational bending and lifting, knee injury, and obesity. Many have suggested that recreational activity and high-level sports involvement are associated with increased risk of osteoarthritis. Although high-impact exercises increase the risk of osteoarthritis, physicians need to still recommend appropriate lower impact aerobic exercise and strengthening exercises for all of our patients to improve their general health, including cardiovascular and musculoskeletal health. Clearly, more research is needed to help us understand how to modify the natural history of this condition in more stringent evidence-based fashion. However, lifestyle medicine approaches combined with conventional therapies are effective in decreasing the disability associated with chronic osteoarthritis.
Lesional gene expression profiling in cutaneous T-cell lymphoma reveals natural clusters associated with disease outcome
Authors: Shin Jessica , Monti Stefano , Aires Daniel J. , Duvic Madeleine , Golub Todd , Jones David A. , Kupper Thomas S.
Published: July 2007

Cutaneous T-cell lymphoma (CTCL) is defined by infiltration of activated and malignant T cells in the skin. The clinical manifestations and prognosis in CTCL are highly variable. In this study, we hypothesized that gene expression analysis in lesional skin biopsies can improve understanding of the disease and its management. Based on 63 skin samples, we performed consensus clustering, revealing 3 patient clusters. Of these, 2 clusters tended to differentiate limited CTCL (stages IA and IB) from more extensive CTCL (stages IB and III). Stage IB patients appeared in both clusters, but those in the limited CTCL cluster were more responsive to treatment than those in the more extensive CTCL cluster. The third cluster was enriched in lymphocyte activation genes and was associated with a high proportion of tumor (stage IIB) lesions. Survival analysis revealed significant differences in event-free survival between clusters, with poorest survival seen in the activated lymphocyte cluster. Using supervised analysis, we further characterized genes significantly associated with lower-stage/treatment-responsive CTCL versus higher-stage/treatment-resistant CTCL. We conclude that transcriptional profiling of CTCL skin lesions reveals clinically relevant signatures, correlating with differences in survival and response to treatment. Additional prospective long-term studies to validate and refine these findings appear warranted.
Normal erythropoiesis but severe polyposis and bleeding anemia in Smad4-deficient mice
Authors: Pan Dejing , Schomber Tibor , Kalberer Christian P. , Terracciano Luigi M. , Hafen Katrin , Krenger Werner , Hao-Shen Hui , Deng Chuxia , Skoda Radek C.
Published: July 2007

The tumor suppressor Smad4 mediates signaling by the transforming growth factor beta (TGF-β) superfamily of ligands. Previous studies showed that several TGF-β family members exert important functions in hematopoiesis. Here, we studied the role of Smad4 in adult murine hematopoiesis using the inducible Mx-Cre/loxP system. Mice with homozygous Smad4 deletion (Smad4Δ/Δ) developed severe anemia 6 to 8 weeks after induction (mean hemoglobin level 70 g/L). The anemia was not transplantable, as wild-type mice reconstituted with Smad4Δ/Δ bone marrow cells had normal peripheral blood counts. These mice did not develop an inflammatory disease typical for mice deficient in TGF-β receptors I and II, suggesting that the suppression of inflammation by TGF-β is Smad4 independent. The same results were obtained when Smad4 alleles were deleted selectively in hematopoietic cells using the VavCre transgenic mice. In contrast, lethally irradiated Smad4Δ/Δ mice that received wild-type bone marrow cells developed anemia similar to Smad4Δ/Δ mice that did not receive a transplant. Liver iron stores were decreased and blood was present in stool, indicating that the anemia was due to blood loss. Multiple polyps in stomach and colon represent a likely source of the bleeding. We conclude that Smad4 is not required for adult erythropoiesis and that anemia is solely the consequence of blood loss.
Interferon-α promotes abnormal vasculogenesis in lupus: a potential pathway for premature atherosclerosis
Authors: Denny Michael F. , Thacker Seth , Mehta Hemal , Somers Emily C. , Dodick Todd , Barrat Franck J. , McCune W. Joseph , Kaplan Mariana J.
Published: July 2007

Individuals with systemic lupus erythematosus (SLE) have a striking increase in premature atherosclerosis of unclear etiology. Accelerated endothelial cell apoptosis occurs in SLE and correlates with endothelial dysfunction. Endothelial progenitor cells (EPCs) and myelomonocytic circulating angiogenic cells (CACs) are crucial in blood vessel repair after vascular damage, and decreased levels or abnormal function of EPCs/CACs are established atherosclerosis risk factors. We investigated if vascular repair is impaired in SLE. We report that SLE patients display abnormal phenotype and function of EPCs/CACs. These abnormalities are characterized by significant decreases in the number of circulating EPCs (310 ± 50 EPCs/mL of blood in SLE versus 639 ± 102 in controls) and significant impairments in the capacity of EPCs/CACs to differentiate into mature ECs and synthesize adequate levels of the proangiogenic molecules vascular endothelial growth factor (VEGF) and hepatic growth factor (HGF). These abnormalities are triggered by interferon-α (IFN-α), which induces EPC and CAC apoptosis and skews myeloid cells toward nonangiogenic phenotypes. Lupus EPCs/CACs have increased IFN-α expression and their supernatants promote higher induction of IFN-inducible genes. Importantly, neutralization of IFN pathways restores a normal EPC/CAC phenotype in lupus. SLE is characterized by an imbalance between endothelial cell damage and repair triggered by type I IFNs, which might promote accelerated atherosclerosis.
Comparison of interactions between beta-hairpin decapeptides and SDS/DPC micelles from experimental and simulation data
Authors: Langham Allison A , Waring Alan J , Kaznessis YN
Published: July 2007

Background

We applied a combined experimental and computational approach to ascertain how peptides interact with host and microbial membrane surrogates, in order to validate simulation methodology we hope will enable the development of insights applicable to the design of novel antimicrobial peptides. We studied the interactions of two truncated versions of the potent, but cytotoxic, antimicrobial octadecapeptide protegrin-1, PC-72 [LCYCRRRFCVC] and PC-73 [CYCRRRFCVC].

Results

We used a combination of FTIR, fluorescence spectroscopy and molecular dynamics simulations to examine the peptides' interactions with sodium dodecylsulfate (SDS) and dodecylphosphocholine (DPC) micelles. The relative amounts of secondary structure determined by FTIR agreed with those from the simulations. Fluorescence spectroscopy, deuterium exchange experiments and the simulations all indicate that neither peptide embeds itself deeply into the micelle core. Although molecular simulations placed both peptides at the micelle-water interface, further examination revealed differences in how certain residues interacted with the micelle core.

Conclusion

We demonstrate here the accuracy of molecular dynamics simulations methods through comparison with experiments, and have used the simulation results to enhance the understanding of how these two peptides interact with the two types of micelles. We find agreement between simulation and experimental results in the final structure of the peptides and in the peptides final conformation with respect to the micelle. Looking in depth at the peptide interactions, we find differences in the interactions between the two peptides from the simulation data; Leu-1 on PC-72 interacts strongly with the SDS micelle, though the interaction is not persistent – the residue withdraws and inserts into the micelle throughout the simulation.
Bayesian refinement of protein functional site matching
Authors: Mardia Kanti V , Nyirongo Vysaul B , Green Peter J , Gold Nicola D , Westhead David R
Published: July 2007

Background

Matching functional sites is a key problem for the understanding of protein function and evolution. The commonly used graph theoretic approach, and other related approaches, require adjustment of a matching distance threshold a priori according to the noise in atomic positions. This is difficult to pre-determine when matching sites related by varying evolutionary distances and crystallographic precision. Furthermore, sometimes the graph method is unable to identify alternative but important solutions in the neighbourhood of the distance based solution because of strict distance constraints. We consider the Bayesian approach to improve graph based solutions. In principle this approach applies to other methods with strict distance matching constraints. The Bayesian method can flexibly incorporate all types of prior information on specific binding sites (e.g. amino acid types) in contrast to combinatorial formulations.

Results

We present a new meta-algorithm for matching protein functional sites (active sites and ligand binding sites) based on an initial graph matching followed by refinement using a Markov chain Monte Carlo (MCMC) procedure. This procedure is an innovative extension to our recent work. The method accounts for the 3-dimensional structure of the site as well as the physico-chemical properties of the constituent amino acids. The MCMC procedure can lead to a significant increase in the number of significant matches compared to the graph method as measured independently by rigorously derived p-values.

Conclusion

MCMC refinement step is able to significantly improve graph based matches. We apply the method to matching NAD(P)(H) binding sites within single Rossmann fold families, between different families in the same superfamily, and in different folds. Within families sites are often well conserved, but there are examples where significant shape based matches do not retain similar amino acid chemistry, indicating that even within families the same ligand may be bound using substantially different physico-chemistry. We also show that the procedure finds significant matches between binding sites for the same co-factor in different families and different folds.
Incorporation of genetic model parameters for cost-effective designs of genetic association studies using DNA pooling
Authors: Ji Fei , Finch Stephen J , Haynes Chad , Mendell Nancy R , Gordon Derek
Published: July 2007

Background

Studies of association methods using DNA pooling of single nucleotide polymorphisms (SNPs) have focused primarily on the effects of "machine-error", number of replicates, and the size of the pool. We use the non-centrality parameter (NCP) for the analysis of variance test to compute the approximate power for genetic association tests with DNA pooling data on cases and controls. We incorporate genetic model parameters into the computation of the NCP. Parameters involved in the power calculation are disease allele frequency, frequency of the marker SNP allele in coupling with the disease locus, disease prevalence, genotype relative risk, sample size, genetic model, number of pools, number of replicates of each pool, and the proportion of variance of the pooled frequency estimate due to machine variability. We compute power for different settings of number of replicates and total number of genotypings when the genetic model parameters are fixed. Several significance levels are considered, including stringent significance levels (due to the increasing popularity of 100 K and 500 K SNP "chip" data). We use a factorial design with two to four settings of each parameter and multiple regression analysis to assess which parameters most significantly affect power.

Results

The power can increase substantially as the genotyping number increases. For a fixed number of genotypings, the power is a function of the number of replicates of each pool such that there is a setting with maximum power. The four most significant parameters affecting power for association are: (1) genotype relative risk, (2) genetic model, (3) sample size, and (4) the interaction term between disease and SNP marker allele probabilities.

Conclusion

For a fixed number of genotypings, there is an optimal number of replicates of each pool that increases as the number of genotypings increases. Power is not substantially reduced when the number of replicates is close to but not equal to the optimal setting.
Influenza pandemic preparedness: motivation for protection among small and medium businesses in Australia
Authors: Watkins Rochelle E , Cooke Feonagh C , Donovan Robert J , MacIntyre C Raina , Itzwerth Ralf , Plant Aileen J
Published: July 2007

Background

Community-wide preparedness for pandemic influenza is an issue that has featured prominently in the recent news media, and is currently a priority for health authorities in many countries. The small and medium business sector is a major provider of private sector employment in Australia, yet we have little information about the preparedness of this sector for pandemic influenza. This study aimed to investigate the association between individual perceptions and preparedness for pandemic influenza among small and medium business owners and managers.

Methods

Semi-structured face-to-face interviews were conducted with 201 small and medium business owners or managers in New South Wales and Western Australia. Eligible small or medium businesses were defined as those that had less than 200 employees. Binomial logistic regression analysis was used to identify the predictors of having considered the impact of, having a plan for, and needing help to prepare for pandemic influenza.

Results

Approximately 6 per cent of participants reported that their business had a plan for pandemic influenza, 39 per cent reported that they had not thought at all about the impact of pandemic influenza on their business, and over 60 per cent stated that they required help to prepare for a pandemic. Beliefs about the severity of pandemic influenza and the ability to respond were significant independent predictors of having a plan for pandemic influenza, and the perception of the risk of pandemic influenza was the most important predictor of both having considered the impact of, and needing help to prepare for a pandemic.

Conclusion

Our findings suggest that small and medium businesses in Australia are not currently well prepared for pandemic influenza. We found that beliefs about the risk, severity, and the ability to respond effectively to the threat of pandemic influenza are important predictors of preparedness. Campaigns targeting small and medium businesses should emphasise the severity of the consequences to their businesses if a pandemic were to occur, and, at the same time, reassure them that there are effective strategies capable of being implemented by small and medium businesses to deal with a pandemic.
Childhood deaths from external causes in Estonia, 2001–2005
Authors: Väli Marika , Lang Katrin , Soonets Ruth , Talumäe Marika , Grjibovski Andrej M
Published: July 2007

Background

In 2000, the overall rate of injury deaths in children aged 0–14 was 28.7 per 100000 in Estonia, which is more than 5 times higher than the corresponding rate in neighbouring Finland. This paper describes childhood injury mortality in Estonia by cause and age groups, and validates registration of these deaths in the Statistical Office of Estonia against the autopsy data.

Methods

The data on causes of all child deaths in Estonia in 2001–2005 were abstracted from the autopsy protocols at the Estonian Bureau of Forensic Medicine. Average annual mortality rates per 100,000 were calculated. Coverage (proportion of the reported injury deaths from the total number of injury deaths) and accuracy (proportion of correctly classified injury deaths) of the registration of causes of death in Statistical Office of Estonia were assessed by comparing the Statistical Office of Estonia data with the data from Estonian Bureau of Forensic Medicine.

Results

Average annual mortality from external causes in 0–14 years-old children in Estonia was 19.1 per 100,000. Asphyxia and transport accidents were the major killers followed by poisoning and suicides. Relative contribution of these causes varied greatly between age groups. Intent of death was unknown for more than 10% of injury deaths. Coverage and accuracy of registration of injury deaths by Statistical Office of Estonia were 91.5% and 95.3%, respectively.

Conclusion

Childhood mortality from injuries in Estonia is among the highest in the EU. The number of injury deaths in Statistical Office of Estonia is slightly underestimated mostly due to misclassification for deaths from diseases. Accuracy of the Statistical Office of Estonia data was high with some underestimation of intentional deaths. Moreover, high proportion of death with unknown intent suggests underestimation of intentional deaths.

Reduction of injury deaths should be given a high priority in Estonia. More information on circumstances around death is needed to enable establishing the intent of death.
Migraine aura or transient ischemic attacks? A five-year follow-up case-control study of women with transient central nervous system disorders in pregnancy
Authors: Ertresvg Janne Marit , Stovner Lars Jacob , Kvavik Lene Ekern , Johnsen Hans-Jorgen , Zwart John-Anker , Helde Grethe , Bovim Gunnar
Published: July 2007

Background

Migraine aura may be difficult to differentiate from transient ischemic attacks and other transient neurological disorders in pregnant women. The aims of the present study were to investigate and diagnose all pregnant women with transient neurological disorders of suspected central nervous system origin, and to compare this group with a control group of pregnant women with regard to vascular risk factors and prognosis.

Methods

During a 28 month period, 41 patients were detected with transient neurological symptoms during pregnancy. These were studied in detail with thorough clinical and laboratory investigations in order to make a certain diagnosis and to evaluate whether the episodes might be of a vascular nature. For comparison, the same investigations were performed in 41 pregnant controls. To assess the prognosis, both patients and controls were followed with questionnaires every year for five years.

Results

Migraine with aura was the most common cause of symptoms during pregnancy, occurring in 34 patients, while 2 were diagnosed with stroke, 2 with carpal tunnel syndrome, 1 with partial epilepsy, 1 with multiple sclerosis and 1 with presyncope. Patients had more headache before pregnancy than controls, but the average levels of vascular risk factors were similar. None of the patients or the controls reported cerebrovascular episodes during the five-year follow-up.

Conclusion

The diagnosis of migraine aura was difficult because for many patients it was their first ever attack and headache tended to be absent or of non-migraineous type. The aura features were more complex, with several aura symptoms and a higher prevalence of sensory and dysphasic aura than usual. Gradually developing aura symptoms, or different aura symptoms occurring in succession as described in the International Classification of Headache Disorders, seem to be useful for differentiating aura from other transient disorders. A meticulous history and clinical neurological examination are more useful than routine supplementary investigations for cerebrovascular disease. The five-year follow-up clearly indicates that migraine with aura in pregnancy usually has a good prognosis with regard to cerebrovascular events.
Analysis of the contribution of cellular and viral RNA to the packaging of APOBEC3G into HIV-1 virions
Authors: Khan Mohammad A , Goila-Gaur Ritu , Opi Sandrine , Miyagi Eri , Takeuchi Hiroaki , Kao Sandra , Strebel Klaus
Published: July 2007

Background

Efficient incorporation of the cellular cytidine deaminase APOBEC3G (APO3G) into HIV-1 virions is necessary for its antiviral activity. Even though cellular RNAs are known to be non-specifically incorporated into virus particles, we have previously found that encapsidation of APO3G into HIV-1 virions is specifically enhanced by viral genomic RNA. Intracellularly, APO3G was found to form large RNA-protein complexes involving a variety of cellular RNAs. The goal of this study was to investigate the possible contribution of host RNAs recently identified in intracellular APO3G ribonucleoprotein complexes to APO3G's encapsidation into HIV-1 virions.

Results

Our results show that 7SL RNA, a component of signal recognition particles, and hY1, hY3, hY4, hY5 RNAs were present in intracellular APO3G complexes and were packaged into HIV-1 particles lacking viral genomic RNA unlike APO3G, which was not packaged in significant amounts into genomic RNA-deficient particles. These results indicate that packaging of 7SL or hY RNAs is not sufficient for the packaging of APO3G into HIV-1 virions. We also tested the encapsidation of several other cellular RNAs including β-actin, GAPDH, α-tubulin, and small nuclear RNAs and determined their effect on the packaging of APO3G into nascent virions. Again, we were unable to observe any correlation between APO3G encapsidation and the packaging of any of these cellular RNAs.

Conclusion

The results from this study support our previous conclusion that viral genomic RNA is a critical determinant for APO3G incorporation into HIV-1 virions. While most cellular RNAs tested in this study were packaged into viruses or virus-like particles we failed to identify a correlation between APO3G encapsidation and the packaging of these cellular RNAs.
Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival
Authors: Datta Antara , Silverman Lee , Phipps Andrew J , Hiraragi Hajime , Ratner Lee , Lairmore Michael D
Published: July 2007

Background

Human T-lymphotropic virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation.

Results

Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C), had enhanced checkpoint kinase 1 (Chk1) serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1), diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes.

Conclusion

Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T-cell survival.