Massachusetts Academy of Math and Science at WPI

BACKGROUND: Trait optimism (positive future expectations) and cynical, hostile attitudes toward others have not been studied together in relation to incident coronary heart disease (CHD) and mortality in postmenopausal women. METHODS AND RESULTS: Participants were 97 253 women (89 259 white, 7994 black) from the Women's Health Initiative who were free of cancer and cardiovascular disease at study entry. Optimism was assessed by the Life Orientation Test-Revised and cynical hostility by the cynicism subscale of the Cook Medley Questionnaire. Cox proportional hazard models produced adjusted hazard ratios (AHRs) for incident CHD (myocardial infarction, angina, percutaneous coronary angioplasty, or coronary artery bypass surgery) and total mortality (CHD, cardiovascular disease, or cancer related) over approximately 8 years. Optimists (top versus bottom quartile ["pessimists"]) had lower age-adjusted rates (per 10 000) of CHD (43 versus 60) and total mortality (46 versus 63). The most cynical, hostile women (top versus bottom quartile) had higher rates of CHD (56 versus 44) and total mortality (63 versus 46). Optimists (versus pessimists) had a lower hazard of CHD (AHR 0.91, 95% CI 0.83 to 0.99), CHD-related mortality (AHR 0.70, 95% CI 0.55 to 0.90), cancer-related mortality (blacks only; AHR 0.56, 95% CI 0.35 to 0.88), and total mortality (AHR 0.86, 95% CI 0.79 to 0.93). Most (versus least) cynical, hostile women had a higher hazard of cancer-related mortality (AHR 1.23, 95% CI 1.09 to 1.40) and total mortality (AHR 1.16, 95% CI 1.07 to 1.27; this effect was pronounced in blacks). Effects of optimism and cynical hostility were independent. CONCLUSIONS: Optimism and cynical hostility are independently associated with important health outcomes in black and white women. Future research should examine whether interventions designed to change attitudes would lead to altered risk.

Twelve rhesus monkeys were vaccinated with SIVmac316 delta nef (lacking nef sequences), and 12 were vaccinated with SIVmac239 delta3 (lacking nef, vpr, and upstream sequences in U3). SIVmac316 and SIVmac239 differ by only eight amino acids in the envelope; these changes render SIVmac316 highly competent for replication in macrophages. Seventeen of the animals developed persistent infections with the vaccine viruses. Seven of the 24 vaccinated animals, however, developed infections that were apparently transient in nature. Six of these seven yielded virus from peripheral blood when tested at weeks 2 and/or 3, three of the seven had transient antibody responses, but none of the seven had persisting antibody responses. The 24 monkeys were challenged in groups of four with 10 rhesus monkey infectious doses of wild-type, pathogenic SIVmac251 at weeks 8, 20, and 79 following receipt of vaccine. None of the seven with apparently transient infections with vaccine virus were protected upon subsequent challenge. Analysis of cell-associated viral loads, CD4+ cell counts, and viral gene sequences present in peripheral blood in the remainder of the monkeys following challenge allowed a number of conclusions. (i) There was a trend toward increased protection with length of time of vaccination. (ii) Solid vaccine protection was achieved by 79 weeks with the highly attenuated SIV239 delta3. (iii) Solid long-term protection was achieved in at least two animals in the absence of complete sterilizing immunity. (iv) Genetic backbone appeared to influence protective capacity; animals vaccinated with SIV239 delta3 were better protected than animals receiving SIV316 delta nef. This better protection correlated with increased levels of the replicating vaccine strain. (v) The titer of virus-neutralizing activity in serum on the day of challenge correlated with protection when measured against a primary stock of SIVmac251 but not when measured against a laboratory-passaged stock. The level of binding antibodies to whole virus by enzyme-linked immunosorbent assay also correlated with protection.

The study of autophagy is rapidly expanding, and our knowledge of the molecular mechanism and its connections to a wide range of physiological processes has increased substantially in the past decade. The vocabulary associated with autophagy has grown concomitantly. In fact, it is difficult for readers--even those who work in the field--to keep up with the ever-expanding terminology associated with the various autophagy-related processes. Accordingly, we have developed a comprehensive glossary of autophagy-related terms that is meant to provide a quick reference for researchers who need a brief reminder of the regulatory effects of transcription factors and chemical agents that induce or inhibit autophagy, the function of the autophagy-related proteins, and the roles of accessory components and structures that are associated with autophagy.

Monero is a privacy-centric cryptocurrency that allows users to obscure their transactions by including chaff coins, called “mixins,” along with the actual coins they spend. In this paper, we empirically evaluate two weaknesses in Monero’s mixin sampling strategy. First, about 62% of transaction inputs with one or more mixins are vulnerable to “chain-reaction” analysis - that is, the real input can be deduced by elimination. Second, Monero mixins are sampled in such a way that they can be easily distinguished from the real coins by their age distribution; in short, the real input is usually the “newest” input. We estimate that this heuristic can be used to guess the real input with 80% accuracy over all transactions with 1 or more mixins. Next, we turn to the Monero ecosystem and study the importance of mining pools and the former anonymous marketplace AlphaBay on the transaction volume. We find that after removing mining pool activity, there remains a large amount of potentially privacy-sensitive transactions that are affected by these weaknesses. We propose and evaluate two countermeasures that can improve the privacy of future transactions.

The Saccharomyces cerevisiae genome contains 16 genes encoding full-size ABC transporters. Each comprises two nucleotide binding folds (NBF) alternating with transmembrane domains (TM). We have studied in detail three plasma membrane multidrug exporters: Pdr5p (TC3.A.1.205.1) and Snq2p (TC3.A.1.205.2) which share NBF-TM-NBF-TM topology as well as Yor1p (TC3.A.1.208.3) which exhibits the reciprocal TM-NBF-TM-NBF topology. The substrate specificity of Pdr5p, Snq2p and Yor1p are largely, but not totally, overlapping as shown by screening the growth inhibition by 349 toxic compounds of combinatorial deletants of these three ABC genes. Multiple deletion of 7 ABC genes (YOR1, SNQ2, PDR5, YCF1, PDR10, PDR11 and PDR15) and of two transcription activation factors (PDR1 and PDR3) renders the cell from 2 to 200 times more sensitive to numerous toxic coumpounds including antifungals used in agriculture or medicine. The use of the pdr1-3 activating mutation and when necessary of the PDR5 promoter in appropriate multideleted hosts allow high levels of expression of Pdr5p, Snq2p or Yor1 p. These overexpressed proteins exhibit ATPase activity in vitro and confer considerable multiple drug resistance in vivo. The latter property can be used for screening specific inhibitors of fungal and other ABC transporters.

Despite considerable advances in the understanding of the pathogenesis of meningococcal disease, this infection remains a major cause of morbidity and mortality globally. The role of the complement system in innate immune defenses against invasive meningococcal disease is well established. Individuals deficient in components of the alternative and terminal complement pathways are highly predisposed to invasive, often recurrent meningococcal infections. Genome-wide analysis studies also point to a central role for complement in disease pathogenesis. Here we review the pathophysiologic events pertinent to the complement system that accompany meningococcal sepsis in humans. Meningococci use several often redundant mechanisms to evade killing by human complement. Capsular polysaccharide and lipooligosaccharide glycan composition play critical roles in complement evasion. Some of the newly described protein vaccine antigens interact with complement components and have sparked considerable research interest.

Autophagy is an evolutionarily conserved intracellular catabolic process that is used by all cells to degrade dysfunctional or unnecessary cytoplasmic components through delivery to the lysosome. Increasing evidence reveals that autophagic dysfunction is associated with human diseases, such as cancer. Paradoxically, although autophagy is well recognized as a cell survival process that promotes tumor development, it can also participate in a caspase-independent form of programmed cell death. Induction of autophagic cell death by some anticancer agents highlights the potential of this process as a cancer treatment modality. Here, we review our current understanding of the molecular mechanism of autophagy and the potential roles of autophagy in cell death, cancer development, and cancer treatment.

Strain and charge co-mediated magnetoelectric coupling are expected in ultra-thin ferromagnetic/ferroelectric multiferroic heterostructures, which could lead to significantly enhanced magnetoelectric coupling. It is however challenging to observe the combined strain charge mediated magnetoelectric coupling, and difficult in quantitatively distinguish these two magnetoelectric coupling mechanisms. We demonstrated in this work, the quantification of the coexistence of strain and surface charge mediated magnetoelectric coupling on ultra-thin Ni0.79Fe0.21/PMN-PT interface by using a Ni0.79Fe0.21/Cu/PMN-PT heterostructure with only strain-mediated magnetoelectric coupling as a control. The NiFe/PMN-PT heterostructure exhibited a high voltage induced effective magnetic field change of 375 Oe enhanced by the surface charge at the PMN-PT interface. Without the enhancement of the charge-mediated magnetoelectric effect by inserting a Cu layer at the PMN-PT interface, the electric field modification of effective magnetic field was 202 Oe. By distinguishing the magnetoelectric coupling mechanisms, a pure surface charge modification of magnetism shows a strong correlation to polarization of PMN-PT. A non-volatile effective magnetic field change of 104 Oe was observed at zero electric field originates from the different remnant polarization state of PMN-PT. The strain and charge co-mediated magnetoelectric coupling in ultra-thin magnetic/ferroelectric heterostructures could lead to power efficient and non-volatile magnetoelectric devices with enhanced magnetoelectric coupling.

The functional significance of microRNA-9 (miR-9) during evolution is evidenced by its conservation at the nucleotide level from flies to humans but not its diverse expression patterns. Recent studies in several model systems reveal that miR-9 can regulate neurogenesis through its actions in neural or non-neural cell lineages. In vertebrates, miR-9 exerts diverse cell-autonomous effects on the proliferation, migration, and differentiation of neural progenitor cells by modulating different mRNA targets. In some developmental contexts, miR-9 suppresses apoptosis and is misregulated in several types of cancer cells, influencing proliferation or metastasis formation. Moreover, downregulation of miR-9 in postmitotic neurons is also implicated in some neurodegenerative diseases. Thus, miR-9 is emerging as an important regulator in development and disease through its ability to modulate different targets in a manner dependent on the developmental stage and the cellular context.

Increasing evidence supports a connection between cancer and metabolism and emphasizes the need to understand how tumors respond to the metabolic microenvironment and how tumor cell metabolism is regulated. The insulin receptor (IR) and its close family member the insulin-like growth factor-1 receptor (IGF-1R) mediate the cellular response to insulin in normal cells and their function is tightly regulated to maintain metabolic homeostasis. These receptors are also expressed on tumor cells and their expression correlates with tumor progression and poor prognosis. Understanding how the IR/IGF-1R pathway functions in tumors is increasing in importance as the efficacy of drugs that target metabolic pathways, such as metformin, are investigated in prospective clinical trials. This review will focus on key signaling intermediates of the IR and IGF-1R, the Insulin Receptor Substrate (IRS) proteins, with an emphasis on IRS-2, and discuss how these adaptor proteins play a pivotal role at the intersection of metabolism and cancer.

HOTAIRM1 is a long intergenic non-coding RNA encoded in the human HOXA gene cluster, with gene expression highly specific for maturing myeloid cells. Knockdown of HOTAIRM1 in the NB4 acute promyelocytic leukemia cell line retarded all-trans retinoid acid (ATRA)-induced granulocytic differentiation, resulting in a significantly larger population of immature and proliferating cells that maintained cell cycle progression from G1 to S phases. Correspondingly, HOTAIRM1 knockdown resulted in retained expression of many otherwise ATRA-suppressed cell cycle and DNA replication genes, and abated ATRA induction of cell surface leukocyte activation, defense response, and other maturation-related genes. Resistance to ATRA-induced cell cycle arrest at the G1/S phase transition in knockdown cells was accompanied by retained expression of ITGA4 (CD49d) and decreased induction of ITGAX (CD11c). The coupling of cell cycle progression with temporal dynamics in the expression patterns of these integrin genes suggests a regulated switch to control the transit from the proliferative phase to granulocytic maturation. Furthermore, ITGAX was among a small number of genes showing perturbation in transcript levels upon HOTAIRM1 knockdown even without ATRA treatment, suggesting a direct pathway of regulation. These results indicate that HOTAIRM1 provides a regulatory link in myeloid maturation by modulating integrin-controlled cell cycle progression at the gene expression level.

BACKGROUND: Surgical management of ankle fractures will be an increasing part of the orthopaedic practice for aging adults. To date, there are few studies comparing outcomes after ankle fracture surgery between patients over and under 65 years. The purpose of this study was to evaluate short- and long-term outcomes after surgical treatment of isolated malleolar fractures in both the elderly and non-elderly population. MATERIALS AND METHODS: Charts and radiographs were reviewed for 25 patients over age 65 and 46 patients under age 65 who underwent operative treatment of an ankle fracture during a 2-year period. Postoperative complications and need for placement in a skilled nursing facility following discharge were noted. The SF-36 and the Olerud and Molander Ankle Score were completed. Mean duration of followup in patients greater than 65 was 27 months and 24 months for patients less than or equal to 65 years. RESULTS: Patients over 65 had a higher number of postoperative complications (40% vs. 11%, p < 0.007), and required nursing home placement more frequently than patients under 65 (p < 0.0001). At long-term followup, the data showed no significant difference in patient reported physical outcomes. CONCLUSION: Early postoperative outcomes after operative fixation of ankle fractures suggest significantly worse outcomes for patients over age 65. However, long-term function in the elderly was comparable to patients under age 65 in this sample. The elderly population had a significantly better mental composite score than the non-elderly.

Juvenile amyotrophic lateral sclerosis (ALS) with basophilic inclusions is a well-recognized entity. However, the molecular underpinnings of this devastating disease are poorly understood. Here, we present genetic and neuropathological characterizations in two young women with fatal rapidly progressive ALS with basophilic inclusions. In one case, a germline mutation (P525L) was detected in the fused in sarcoma/translocated in liposarcoma (FUS/TLS) gene, whereas no mutation was identified in the other case. Postmortem examination in both cases revealed severe loss of spinal motor neurons with remaining neurons showing basophilic inclusions that contain abnormal aggregates of FUS proteins and disorganized intracellular organelles, including mitochondria and endoplasmic reticulum. In both patients, the FUS-positive inclusions were also detected in neurons in layers IV-V of cerebral cortex and several brainstem nuclei. In contrast, spinal motor neurons in patients with late-onset sporadic ALS showed no evidence of abnormal accumulation of FUS protein. These results underscore the importance of FUS mutations and pathology in rapidly progressive juvenile ALS. Furthermore, our study represents the first detailed characterizations of neuropathological findings in rapidly progressive juvenile ALS patients with a mutation in the FUS/TLS gene.

In order to explain the variability noted in the fluorescein staining characteristics of the epigastric axial flap in the experimental laboratory rat, the anatomy of the blood supply of this particular flap was investigated. In 10 rats, the vascular pattern of the superficial epigastric trunk to the abdominal skin was found to be similar. A small branch of the trunk extended toward the medial abdominal skin to collateralize with a branch of the internal mammary vessel entering from the chest skin. A large extension of the superficial epigastric trunk extended laterally toward the midlateral point of the animal and cephalad to collateralize with the vessels in the lateral chest wall, presumably the lateral thoracic artery. Fluorescein staining characteristics of 10 flaps including or excluding the lateral branch were examined, and a significant difference was found in the immediate fluorescein staining characteristics. The flaps that included the lateral branch fluoresced to an average of 89.2 percent of the flap length, and those in which the lateral branch was excluded fluoresced to 68.7 percent of the flap length. The use of this flap model in experimental flap research should include a precise description of the anatomy of the particular flap used in order to ensure reproducible results.

By virtue of its ability to regulate both protein turnover and non-proteolytic signalling functions, ubiquitin protein conjugation has been implicated in the control of multiple cellular processes, including protein localization, cell cycle control, transcription regulation, DNA damage repair, and endocytosis. Ubiquitin metabolism enzymes have been identified as either oncogenes or tumor suppressors in a variety of cancers. Given that ubiquitin metabolism is governed by enzymes--E1, E2, E3, E4, deubiquitinases (DUBs), and the proteasome- the system as a whole is ripe for target and drug discovery in cancer. Of the ubiquitin/proteasome system components, the E3's and DUBs can recognize substrates with the most specificity, and are thus of key interest as drug targets in cancer. This review examines the molecular role in cancer, relevant substrates, and potential for pharmacologic development, of E3's and DUBs that have been associated thus far with human malignancies as oncogenes or tumor suppressors.

The role of Fc glycans on clearance of IgG molecule has been examined by various groups in experiments where specific glycans have been enriched or the entire spectrum of glycans was studied after administration in pre-clinical or clinical pharmacokinetic (PK) studies. The overall conclusions from these studies are inconsistent, which may result from differences in antibody structure or experimental design. In the present study a well-characterized recombinant monoclonal IgG1 molecule (mAb-1) was analyzed from serum samples obtained from a human PK study. mAb-1 was recovered from serum using its ligand cross-linked to Sepharose beads. The overall purity and recovery of all isoforms were carefully evaluated using a variety of methods. Glycans were then enzymatically cleaved, labeled using 2-aminobenzamide and analyzed by normal phase high performance liquid chromatography. The assays for recovering mAb-1 from serum and subsequent glycan analysis were rigorously qualified at a lower limit of quantitation of 15 μg/mL, thus permitting analysis to day 14 of the clinical PK study. Eight glycans were monitored and classified into two groups: (1) the oligomannose type structures (M5, M6 and M7) and (2) fucosylated biantennary oligosaccharides (FBO) structures (NGA2F, NA1F, NA2F, NA1F-GlcNAc and NGA2F-GlcNAc). We observed that the oligomannose species were cleared at a much faster rate (40%) than FBOs and conclude that high mannose species should be carefully monitored and controlled as they may affect PK of the therapeutic; they should thus be considered an important quality attribute. These observations were only possible through the application of rigorous analytical methods that we believe will need to be employed when comparing innovator and biosimilar molecules.

Injectable engineered cartilage that maintains a predictable shape and volume would allow recontouring of craniomaxillofacial irregularities with minimally invasive techniques. This study investigated how chondrocytes from different cartilage sources, encapsulated in fibrin polymer, affected construct mass and volume with time. Swine auricular, costal, and articular chondrocytes were isolated and mixed with fibrin polymer (cell concentration of 40 x 10 cells/ml for all groups). Eight samples (1 cm x 1 cm x 0.3 cm) per group were implanted into nude mice for each time period (4, 8, and 12 weeks). The dimensions and mass of each specimen were recorded before implantation and after explantation. Ratios comparing final measurements and original measurements were calculated. Histological, biochemical, and biomechanical analyses were performed. Histological evaluations (n = 3) indicated that new cartilaginous matrix was synthesized by the transplanted chondrocytes in all experimental groups. At 12 weeks, the ratios of dimension and mass (n = 8) for auricular chondrocyte constructs increased by 20 to 30 percent, the ratios for costal chondrocyte constructs were equal to the initial values, and the ratios for articular chondrocyte constructs decreased by 40 to 50 percent. Constructs made with auricular chondrocytes had the highest modulus (n = 3 to 5) and glycosaminoglycan content (n = 4 or 5) and the lowest permeability value (n = 3 to 5) and water content (n = 4 or 5). Constructs made with articular chondrocytes had the lowest modulus and glycosaminoglycan content and the highest permeability value and water content (p < 0.05). The amounts of hydroxyproline (n = 5) and DNA (n = 5) were not significantly different among the experimental groups (p > 0.05). It was possible to engineer injectable cartilage with chondrocytes from different sources, resulting in neocartilage with different properties. Although cartilage made with articular chondrocytes shrank and cartilage made with auricular chondrocytes overgrew, the injectable tissue-engineered cartilage made with costal chondrocytes was stable during the time periods studied. Furthermore, the biomechanical properties of the engineered cartilage made with auricular or costal chondrocytes were superior to those of cartilage made with articular chondrocytes, in this model.

BACKGROUND AND PURPOSE: Despite a paucity of evidence supporting a true association of ischemic stroke and the inherited thrombophilias, it is common practice for many neurologists to order these tests as part of the work-up of ischemic stroke, especially in young patients. Treatment with oral anticoagulation is often used in patients with positive results for the inherited thrombophilias. METHODS: We reviewed the literature focusing on case-control studies of the 5 most commonly inherited disorders of coagulation: protein C deficiency, protein S deficiency, antithrombin deficiency, and the factor V Leiden and prothrombin gene mutations in patients with stroke. We also analyzed the available data on stroke patients with inherited thrombophilia and patent foramen ovale. RESULTS: Multiple case-control studies have not convincingly shown an association of the inherited thrombophilias with ischemic stroke, even in young patients and patients with patent foramen ovale. CONCLUSIONS: If there is an association between the inherited thrombophilias and arterial stroke, then it is a weak one, likely enhanced by other prothrombotic risk factors. The consequences of ordering these tests and attributing causality to an arterial event can result in significant costs to the health care system and pose a potential risk to patients, because this may lead to inappropriate use of long-term oral anticoagulants, exposing patients to harm without a clearly defined benefit.

In the repair of cartilage defects, autologous tissue offers the advantage of lasting biocompatibility. The ability of bovine chondrocytes isolated from hyaline cartilage to generate tissue-engineered cartilage in a predetermined shape, such as a human ear, has been demonstrated; however, the potential of chondrocytes isolated from human elastic cartilage remains unknown. In this study, the authors examined the multiplication characteristics of human auricular chondrocytes and the ability of these cells to generate new elastic cartilage as a function of the length of time they are maintained in vitro. Human auricular cartilage, harvested from patients 5 to 17 years of age, was digested in collagenase, and the chondrocytes were isolated and cultured in vitro for up to 12 weeks. Cells were trypsinized, counted, and passaged every 2 weeks. Chondrocyte-polymer (polyglycolic acid) constructs were created at each passage and then implanted into athymic mice for 8 weeks. The ability of the cells to multiply in vitro and their ability to generate new cartilage as a function of the time they had been maintained in vitro were studied. A total of 31 experimental constructs from 12 patients were implanted and compared with a control group of constructs without chondrocytes. In parallel, a representative sample of cells was evaluated to determine the presence of collagen. The doubling rate of human auricular chondrocytes in vitro remained constant within the population studied. New tissue developed in 22 of 31 experimental implants. This tissue demonstrated the physical characteristics of auricular cartilage on gross inspection. Histologically, specimens exhibited dense cellularity and lacunae-containing cells embedded in a basophilic matrix. The specimens resembled immature cartilage and were partially devoid of the synthetic material of which the construct had been composed. Analyses for collagen, proteoglycans, and elastin were consistent with elastic cartilage. No cartilage was detected in the control implants. Human auricular chondrocytes multiply well in vitro and possess the ability to form new cartilage when seeded onto a three-dimensional scaffold. These growth characteristics might some day enable chondrocytes isolated from a small auricular biopsy to be expanded in vitro to generate a large, custom-shaped, autologous graft for clinical reconstruction of a cartilage defect, such as for congenital microtia.

Each year, more than one million patients undergo some type of procedure involving cartilage reconstruction. Polymer hydrogels such as alginate have been demonstrated to be effective carriers of chondrocytes for subcutaneous cartilage formation. The goal of this study was to develop a simple method to create complex structures with good three-dimensional tolerance in order to form cartilage in specific shapes in an autologous animal model. Six alginate implants that had been seeded with autologous chondrocytes through an injection molding process were implanted subcutaneously in sheep, harvested after 6 months, and analyzed histologically, biochemically, and biomechanically, in comparison with original auricular cartilage. Molds of craniofacial implants were prepared with Silastic E RTV (Dow Corning, Midland, Mich.). Chondrocytes were harvested from sheep auricular cartilage and suspended in 2% alginate at a concentration of 50 x 10(6) cells/ml. The mixture of cells and gel was injected into the Silastic molds and removed after 20 minutes. Chondrocyte-alginate constructs were implanted subcutaneously in the necks of the sheep from which the cells had originally been harvested, and the constructs were removed after 30 weeks. Analyses of the implanted constructs indicated cartilage formation with three-dimensional shape retention. The proteoglycan and collagen contents of the constructs increased with time to approximately 80 percent of the values for native tissue. The equilibrium modulus and the hydraulic permeability were 74 and 105 percent of those of native sheep auricular cartilage, respectively.