Month: January 2016

Scheduled Refworks Downtime 1/18/2016

On Saturday, January 16, 2016, ProQuest will be upgrading its systems infrastructure. ProQuest (including Refworks and Digital Dissertations) platforms will be unavailable beginning at at 10:00 PM Eastern Standard Time and will last for 8 hours.

Posted in Service Disruptions

Hot Topics in Research

The PCOM Library announces a new information service focused on very recent trends in medical research. The new service kicks-off this month featuring radiology, brain/neurosurgery,cardiology, dementia/memory impairment and cancers of the breast, lung and prostate.

The collection of hot topic articles is accessible directly at http://library.pcom.edu/category/hot-topics/ or by linking from the “Hot Topics in Research” button on the Library’s homepage.
hot topics home page screenshot

Articles are presented in abstract form, with easy links to the full-text versions for detailed research information.

If readers have other suggestions for future monthly hot topics in medical research, please send an email to PJ Grier, associate director at: PJGrier@pcom.edu.

Posted in Front Page, Library News

Prostate cancer discovery may make it easier to kill cancer cells

Checkpoint Kinase 2 Negatively Regulates Androgen Sensitivity and Prostate Cancer Cell Growth

Abstract:

Prostate cancer is the second leading cause of cancer death in American men, and curing metastatic disease remains a significant challenge. Nearly all patients with disseminated prostate cancer initially respond to androgen deprivation therapy (ADT), but virtually all patients will relapse and develop incurable castrationresistant prostate cancer (CRPC). A high-throughput RNAi screen to identify signaling pathways regulating prostate cancer cell growth led to our discovery that checkpoint kinase 2 (CHK2) knockdown dramatically increased prostate cancer growth and hypersensitized cells to low androgen levels. Mechanistic investigations revealed that the effects of CHK2 were dependent on the downstream signaling proteins CDC25C and CDK1. Moreover, CHK2depletion increased androgen receptor (AR) transcriptional activity on androgen-regulated genes, substantiating the finding that CHK2 affects prostate cancer proliferation, partly, through the AR. Remarkably, we further show that CHK2 is a novel ARrepressed gene, suggestive of a negative feedback loop between CHK2 and AR. In addition, we provide evidence that CHK2 physically associates with the AR and that cell-cycle inhibition increased this association. Finally, IHC analysis of CHK2 in prostate cancer patient samples demonstrated a decrease in CHK2 expression in high-grade tumors. In conclusion, we propose that CHK2 is a negative regulator of androgen sensitivity and prostate cancer growth, and that CHK2 signaling is lost during prostate cancer progression to castration resistance. Thus, perturbing CHK2 signaling may offer a new therapeutic approach for sensitizing CRPC to ADT and radiation.

 

Cancer Research. 12/1/2015, Vol. 75 Issue 23, p5093-5105. 13p.

Posted in Hot Topics in Research, Oncology, Prostate, Uncategorized

Non-lethal Inhibition of Gut Microbial Trimethylamine Production for the Treatment of Atherosclerosis

Non-lethal Inhibition of Gut

Abstract:

Trimethylamine (TMA) N-oxide (TMAO), a gut-microbiota-dependent metabolite, both enhances atherosclerosis in animal models and is associated with cardiovascular risks in clinical studies. Here, we investigate the impact of targeted inhibition of the first step in TMAO generation, commensal microbial TMA production, on diet-induced atherosclerosis. A structural analog of choline, 3,3-dimethyl-1-butanol (DMB), is shown to non-lethally inhibit TMA formation from cultured microbes, to inhibit distinct microbial TMA lyases, and to both inhibit TMA production from physiologic polymicrobial cultures (e.g., intestinal contents, human feces) and reduce TMAO levels in mice fed a high-choline or L-carnitine diet. DMB inhibited choline diet-enhanced endogenous macrophage foam cell formation and atherosclerotic lesion development in apolipoprotein e−/− mice without alterations in circulating cholesterol levels. The present studies suggest that targeting gut microbial production of TMA specifically and non-lethal microbial inhibitors in general may serve as a potential therapeutic approach for the treatment of cardiometabolic diseases. •Gut microbial trimethylamine lyases are a therapeutic target for atherosclerosis•3,3-dimethyl-1-butanol inhibits microbial trimethylamine formation•3,3-dimethyl-1-butanol attenuates choline diet-enhanced atherosclerosis•Non-lethal gut microbial enzyme inhibition can impact host cardiometabolic phenotypes Drugging the gut microbiota with a non-lethal inhibitor that blocks production of the metabolite trimethylamine reduces the formation of atherosclerotic lesions and represents the first step toward treatment of cardiometabolic diseases by targeting the microbiome.

Cell 17 December 2015 163(7):1585-1595

Posted in Cardiology, Hot Topics in Research, Uncategorized

Practical experiences with eribulin in patients with metastatic breast cancer

Practical experiences with eribulin in patients with metastatic breast cancer

Background There is currently no standard therapy for women with metastatic or locally recurrent breast cancer. The microtubule polymerization inhibitor eribulin, approved in March 2011, is the first monochemotherapy with a proven survival benefit and tolerable toxicity in this patient group.

Patients and methods Using a retrospective analysis of 27 mostly heavily pretreated patients in two large German breast cancer centers, the efficacy and tolerability of eribulin in daily practice were compared with the results of the pivotal EMBRACE and 301 studies.

Results Despite the patients being older and having more advanced disease, the retrospective analysis showed a comparable progression-free survival of 3.7 months. When eribulin was used in an early-line treatment, the progression-free survival observed was 7 weeks longer compared with use in a late-line therapy. The differences in tolerability were not significant.

Anti-Cancer Drugs
Issue: Volume 27(2), February 2016, p 112–117
Posted in Breast, Hot Topics in Research, Oncology

Management of Pulmonary Nodules by Community Pulmonologists

Management of Pulmonary Nodules by Community Pulmonologists

BACKGROUND: Pulmonary nodules (PNs) are a common reason for referral to pulmonologists. Th e majority of data for the evaluation and management of PNs is derived from studies performed in academic medical centers. Little is known about the prevalence and diagnosis of PNs, the use of diagnostic testing, or the management of PNs by community pulmonologists. METHODS: Th is multicenter observational record review evaluated 377 patients aged 40 to 89 years referred to 18 geographically diverse community pulmonary practices for intermediate PNs (8-20 mm). Study measures included the prevalence of malignancy, procedure/test use, and nodule pretest probability of malignancy as calculated by two previously validated models. Th e relationship between calculated pretest probability and management decisions was evaluated. RESULTS: Th e prevalence of malignancy was 25% (n 5 94). Nearly one-half of the patients (46%, n 5 175) had surveillance alone. Biopsy was performed on 125 patients (33.2%). A total of 77 patients (20.4%) underwent surgery, of whom 35% (n 5 27) had benign disease. PET scan was used in 141 patients (37%). Th e false-positive rate for PET scan was 39% (95% CI, 27.1%-52.1%). Pretest probability of malignancy calculations showed that 9.5% (n 5 36) were at a low risk, 79.6% (n 5 300) were at a moderate risk, and 10.8% (n 5 41) were at a high risk of malignancy. Th e rate of surgical resection was similar among the three groups (17%, 21%, 17%, respectively; P 5 .69). CONCLUSIONS: A substantial fraction of intermediate-sized nodules referred to pulmonologists ultimately prove to be lung cancer. Despite advances in imaging and nonsurgical biopsy techniques, invasive sampling of low-risk nodules and surgical resection of benign nodules remain common, suggesting a lack of adherence to guidelines for the management of PNs.

CHEST2015; 148(6): 1405 – 1414

Posted in Hot Topics in Research, Lung, Oncology

Effects of aging on circadian patterns of gene expression in the human prefrontal cortex

Effects of aging on circadian patterns of gene expression in the human prefrontal cortex

With aging, significant changes in circadian rhythms occur, including a shift in phase toward a “morning” chronotype and a loss of rhythmicity in circulating hormones. However, the effects of aging on molecular rhythms in the human brain have remained elusive. Here, we used a previously described time-of-death analysis to identify transcripts throughout the genome that have a significant circadian rhythm in expression in the human prefrontal cortex [Brodmann’s area 11 (BA11) and BA47]. Expression levels were determined by microarray analysis in 146 individuals. Rhythmicity in expression was found in ∼10% of detected transcripts (P < 0.05). Using a metaanalysis across the two brain areas, we identified a core set of 235 genes (q < 0.05) with significant circadian rhythms of expression. These 235 genes showed 92% concordance in the phase of expression between the two areas. In addition to the canonical core circadian genes, a number of other genes were found to exhibit rhythmic expression in the brain. Notably, we identified more than 1,000 genes (1,186 in BA11; 1,591 in BA47) that exhibited age-dependent rhythmicity or alterations in rhythmicity patterns with aging. Interestingly, a set of transcripts gained rhythmicity in older individuals, which may represent a compensatory mechanism due to a loss of canonical clock function. Thus, we confirm that rhythmic gene expression can be reliably measured in human brain and identified for the first time (to our knowledge) significant changes in molecular rhythms with aging that may contribute to altered cognition, sleep, and mood in later life.

 

Cho-Yi Chen, Proceedings of the National Academy of Sciences 2015 of the USA ; published ahead of print December 22, 2015, doi:10.1073/pnas.1508249112. 

 

Posted in Brain, Dementia, Hot Topics in Research, Memory Impairment, Neurology

Findings from Structural MR Imaging in Military Traumatic Brain Injury

Findings from Structural MR Imaging in Military Traumatic Brain Injury

To describe the initial neuroradiology findings in a cohort of military service members with primarily chronic mild traumatic brain injury (TBI) from blast by using an integrated magnetic resonance (MR) imaging protocol.

Materials and Methods

This study was approved by the Walter Reed National Military Medical Center institutional review board and is compliant with HIPAA guidelines. All participants were military service members or dependents recruited between August 2009 and August 2014. There were 834 participants with a history of TBI and 42 participants in a control group without TBI (not explicitly age- and sex-matched). MR examinations were performed at 3 T primarily with three-dimensional volume imaging at smaller than 1 mm3 voxels for the structural portion of the examination. The structural portion of this examination, including T1-weighted, T2-weighted, before and after contrast agent administrtion T2 fluid attenuation inversion recovery, and susceptibility-weighted images, was evaluated by neuroradiologists by using a modified version of the neuroradiology TBI common data elements (CDEs). Incident odds ratios (ORs) between the TBI participants and a comparison group without TBI were calculated.

The 834 participants were diagnosed with predominantly chronic (mean, 1381 days; median, 888 days after injury) and mild (92% [768 of 834]) TBI. Of these participants, 84.2% (688 of 817) reported one or more blast-related incident and 63.0% (515 of 817) reported loss of consciousness at the time of injury. The presence of white matter T2-weighted hyperintense areas was the most common pathologic finding, observed in 51.8% (432 of 834; OR, 1.75) of TBI participants. Cerebral microhemorrhages were observed in a small percentage of participants (7.2% [60 of 834]; OR, 6.64) and showed increased incidence with TBI severity (P < .001, moderate and severe vs mild). T2-weighted hyperintense areas and microhemorrhages did not collocate by visual inspection. Pituitary abnormalities were identified in a large proportion (29.0% [242 of 834]; OR, 16.8) of TBI participants.

Conclusion

Blast-related injury and loss of consciousness is common in military TBI. Structural MR imaging demonstrates a high incidence of white matter T2-weighted hyperintense areas and pituitary abnormalities, with a low incidence of microhemorrhage in the chronic phase.

 

Radiology; 278;1 (Ahead of Print), Gerard Riedy, MD, PhD , Justin S. Senseney, MS , Wei Liu, DSc , John Ollinger, PhD , Elyssa Sham, BA , Pavel Krapiva, MD , Jigar B. Patel, MD , Alice Smith, MD , Ping-Hong Yeh, PhD , John Graner, PhD , Dominic Nathan, PhD , Jesus Caban, PhD , Louis M. French, PsyD , Jamie Harper, MPH , Victoria Eskay, BA , John Morissette , Terrence R. Oakes, PhD. DOI: http://dx.doi.org/10.1148/radiol.2015150438
Posted in Brain, Hot Topics in Research, Neurosurgery, Radiology