BACKGROUND

The congenital long-QT syndrome (LQTS) is caused by mutations on several genes, all of which encode cardiac ion channels. The progressive understanding of the electrophysiological consequences of these mutations opens unforeseen possibilities for genotype-phenotype correlation studies. Preliminary observations suggested that the conditions ("triggers") associated with cardiac events may in large part be gene specific.

RESULTS

We identified 670 LQTS patients of known genotype (LQT1, n=371; LQT2, n=234; LQT3, n=65) who had symptoms (syncope, cardiac arrest, sudden death) and examined whether 3 specific triggers (exercise, emotion, and sleep/rest without arousal) differed according to genotype. LQT1 patients experienced the majority of their events (62%) during exercise, and only 3% occurred during rest/sleep. These percentages were almost reversed among LQT2 and LQT3 patients, who were less likely to have events during exercise (13%) and more likely to have events during rest/sleep (29% and 39%). Lethal and nonlethal events followed the same pattern. Corrected QT interval did not differ among LQT1, LQT2, and LQT3 patients (498, 497, and 506 ms, respectively). The percent of patients who were free of recurrence with ss-blocker therapy was higher and the death rate was lower among LQT1 patients (81% and 4%, respectively) than among LQT2 (59% and 4%, respectively) and LQT3 (50% and 17%, respectively) patients.

CONCLUSIONS

Life-threatening arrhythmias in LQTS patients tend to occur under specific circumstances in a gene-specific manner. These data allow new insights into the mechanisms that relate the electrophysiological consequences of mutations on specific genes to clinical manifestations and offer the possibility of complementing traditional therapy with gene-specific approaches.

OBJECTIVE

To investigate the ability of cerebrospinal fluid (CSF) and plasma measures to discriminate early-stage Alzheimer disease (AD) (defined by clinical criteria and presence/absence of brain amyloid) from nondemented aging and to assess whether these biomarkers can predict future dementia in cognitively normal individuals.

METHODS

Evaluation of CSF beta-amyloid(40) (Abeta(40)), Abeta(42), tau, phosphorylated tau(181), and plasma Abeta(40) and Abeta(42) and longitudinal clinical follow-up (from 1 to 8 years).

METHODS

Longitudinal studies of healthy aging and dementia through an AD research center.

METHODS

Community-dwelling volunteers (n = 139) aged 60 to 91 years and clinically judged as cognitively normal (Clinical Dementia Rating [CDR], 0) or having very mild (CDR, 0.5) or mild (CDR, 1) AD dementia.

RESULTS

Individuals with very mild or mild AD have reduced mean levels of CSF Abeta(42) and increased levels of CSF tau and phosphorylated tau(181). Cerebrospinal fluid Abeta(42) level completely corresponds with the presence or absence of brain amyloid (imaged with Pittsburgh Compound B) in demented and nondemented individuals. The CSF tau/Abeta(42) ratio (adjusted hazard ratio, 5.21; 95% confidence interval, 1.58-17.22) and phosphorylated tau(181)/Abeta(42) ratio (adjusted hazard ratio, 4.39; 95% confidence interval, 1.62-11.86) predict conversion from a CDR of 0 to a CDR greater than 0.

CONCLUSIONS

The very mildest symptomatic stage of AD exhibits the same CSF biomarker phenotype as more advanced AD. In addition, levels of CSF Abeta(42), when combined with amyloid imaging, augment clinical methods for identifying in individuals with brain amyloid deposits whether dementia is present or not. Importantly, CSF tau/Abeta(42) ratios show strong promise as antecedent (preclinical) biomarkers that predict future dementia in cognitively normal older adults.

A maximal multistage 20 m shuttle run test was designed to determine the maximal aerobic power of schoolchildren, healthy adults attending fitness class and athletes performing in sports with frequent stops and starts (e.g. basketball, fencing and so on). Subjects run back and forth on a 20 m course and must touch the 20 m line; at the same time a sound signal is emitted from a prerecorded tape. Frequency of the sound signals is increased 0.5 km h-1 each minute from a starting speed of 8.5 km h-1. When the subject can no longer follow the pace, the last stage number announced is used to predict maximal oxygen uptake (VO2max) (Y, ml kg-1 min-1) from the speed (X, km h-1) corresponding to that stage (speed = 8 + 0.5 stage no.) and age (A, year): Y = 31.025 + 3.238 X - 3.248A + 0.1536AX, r = 0.71 with 188 boys and girls aged 8-19 years. To obtain this regression, the test was performed individually. Right upon termination VO2 was measured with four 20 s samples and VO2max was estimated by retroextrapolating the O2 recovery curve at time zero of recovery. For adults, similar measurements indicated that the same equation could be used keeping age constant at 18 (r = 0.90, n = 77 men and women 18-50 years old). Test-retest reliability coefficients were 0.89 for children (139 boys and girls 6-16 years old) and 0.95 for adults (81 men and women, 20-45 years old).(ABSTRACT TRUNCATED AT 250 WORDS)

BACKGROUND

Although numerous studies have shown that the status of the sentinel node is an accurate predictor of the status of the axillary nodes in breast cancer, the efficacy and safety of sentinel-node biopsy require validation.

METHODS

From March 1998 to December 1999, we randomly assigned 516 patients with primary breast cancer in whom the tumor was less than or equal to 2 cm in diameter either to sentinel-node biopsy and total axillary dissection (the axillary-dissection group) or to sentinel-node biopsy followed by axillary dissection only if the sentinel node contained metastases (the sentinel-node group).

RESULTS

The number of sentinel nodes found was the same in the two groups. A sentinel node was positive in 83 of the 257 patients in the axillary-dissection group (32.3 percent), and in 92 of the 259 patients in the sentinel-node group (35.5 percent). In the axillary-dissection group, the overall accuracy of the sentinel-node status was 96.9 percent, the sensitivity 91.2 percent, and the specificity 100 percent. There was less pain and better arm mobility in the patients who underwent sentinel-node biopsy only than in those who also underwent axillary dissection. There were 15 events associated with breast cancer in the axillary-dissection group and 10 such events in the sentinel-node group. Among the 167 patients who did not undergo axillary dissection, there were no cases of overt axillary metastasis during follow-up.

CONCLUSIONS

Sentinel-node biopsy is a safe and accurate method of screening the axillary nodes for metastasis in women with a small breast cancer.

Mice of the strain MRL/Mp-lpr/lpr develop a lupus erythematosus-like syndrome that includes the production of autoantibodies specific for nucleic acid-containing cellular components. We have fused spleen cells from such a mouse with the myeloma SP 2/0 and examined the antibodies produced by the resultant cloned hybrid cell lines by using immunoprecipitation and immunofluorescence techniques. Three types of monoclonal antibodies, specific for Sm, DNA, or rRNA, all antigens to which patients who have lupus make antibodies, have been identified. Patient anti-Sm antibody had previously been reported to precipitate five small nuclear ribonucleoproteins that contain U-1, U-2, U-4, U-5, and U-6 RNAs. The monoclonal anti-Sm antibody gives the same immunoprecipitation pattern, providing direct evidence that the Sm antigen resides on all these RNA-protein complexes. Monoclonal anti-Sm antibody will be valuable in deciphering the biological function of these ubiquitous small nuclear RNPs. A simple competition radioimmunoassay using the monoclonal anti-Sm antibody to titer patient sera is also presented. Uses of monoclonal antibodies for the study of autoimmune disease are discussed.

Understanding the function of genes mutated in hereditary forms of Parkinson's disease yields insight into disease etiology and reveals new pathways in cell biology. Although mutations or variants in many genes increase the susceptibility to Parkinson's disease, only a handful of monogenic causes of parkinsonism have been identified. Biochemical and genetic studies reveal that the products of two genes that are mutated in autosomal recessive parkinsonism, PINK1 and Parkin, normally work together in the same pathway to govern mitochondrial quality control, bolstering previous evidence that mitochondrial damage is involved in Parkinson's disease. PINK1 accumulates on the outer membrane of damaged mitochondria, activates Parkin's E3 ubiquitin ligase activity, and recruits Parkin to the dysfunctional mitochondrion. Then, Parkin ubiquitinates outer mitochondrial membrane proteins to trigger selective autophagy. This review covers the normal functions that PINK1 and Parkin play within cells, their molecular mechanisms of action, and the pathophysiological consequences of their loss.

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder, commonly caused by a point mutation in the lamin A gene that results in a protein lacking 50 aa near the C terminus, denoted LADelta50. Here we show by light and electron microscopy that HGPS is associated with significant changes in nuclear shape, including lobulation of the nuclear envelope, thickening of the nuclear lamina, loss of peripheral heterochromatin, and clustering of nuclear pores. These structural defects worsen as HGPS cells age in culture, and their severity correlates with an apparent increase in LADelta50. Introduction of LADelta50 into normal cells by transfection or protein injection induces the same changes. We hypothesize that these alterations in nuclear structure are due to a concentration-dependent dominant-negative effect of LADelta50, leading to the disruption of lamin-related functions ranging from the maintenance of nuclear shape to regulation of gene expression and DNA replication.

This paper provides evidence that normal animal cells possess a unique regulatory mechanism to shift them between proliferative and quiescent states. Cells cease to increase in number under a diversity of suboptimal nutritional conditions, whereas a uniformity of metabolic changes follows these nutritional shifts. Evidence is given here that cells are put into the same quiescent state by each of these diverse blocks to proliferation and that cells escape at the same point in G(1) of the cell cycle when nutrition is restored. The name restriction point is proposed for the specific time in the cell cycle at which this critical release event occurs. The restriction point control is proposed to permit normal cells to retain viability by a shift to a minimal metabolism upon differentiation in vivo and in vitro when conditions are suboptimal for growth. Malignant cells are proposed to have lost their restriction point control. Hence, under very adverse conditions, as in the presence of antitumor agents, they stop randomly in their division cycle and die.

Several specific conclusions can be drawn from these studies: 1. IL-4 is required for the generation of both primary polyclonal and secondary antigen-specific IgE responses in vivo. 2. IL-4 is required to maintain established, ongoing, antigen-specific and polyclonal IgE responses. 3. Most, but not all, polyclonal IgE production during a secondary immune response is IL-4-dependent. Memory B cells that have already switched to IgE at the DNA level may no longer require stimulation with IL-4 to be induced to secrete IgE. 4. The generation of a secondary IgE response is not dependent upon the presence of IL-4 during primary immunization. However, if IL-4 is not present during primary immunization, it is required during secondary immunization for the generation of an IgE response. 5. IL-4 does not appear to be required for the generation of in vivo IgG1 responses, and in at least some instances, does not contribute significantly to the generation of IgG1 responses in vivo. 6. A late-acting form of T-cell help other than IL-4 appears to be required for the generation of an IgE, but not an IgG1 response. 7. An antibody that inhibits IL-4 binding to IL-4 receptors affects Ig isotype selection in the same way as an antibody that neutralizes IL-4. 8. IFN-gamma can act in both spontaneous and induced immune responses to suppress IgE production. 9. IFN-gamma can also suppress IgG1 production and stimulate IgG2a production. However, IFN-gamma appears to suppress polyclonal IgG1 responses more than antigen-specific IgG1 responses, and it enhances, but is not required for, the generation of IgG2a responses. 10. IFN-alpha appears to resemble IFN-gamma in its ability to inhibit IgE and enhance IgG2a responses in GaM delta-injected mice, but it requires the presence of IFN-gamma to suppress IgG1 production in these mice. 11. Both IFN-alpha and IFN-gamma appear to be able to decrease IgE production in some human patients. 12. There is no direct evidence that IL-5 contributes to the generation of in vivo antibody responses. Two general conclusions may also be drawn.(ABSTRACT TRUNCATED AT 400 WORDS)

Toll-like receptor (TLR) family acts as pattern recognition receptors for pathogen-specific molecular patterns. We previously showed that TLR2 recognizes Gram-positive bacterial components whereas TLR4 recognizes LPS, a component of Gram-negative bacteria. MyD88 is shown to be an adaptor molecule essential for TLR family signaling. To investigate the role of TLR family in host defense against Gram-positive bacteria, we infected TLR2- and MyD88-deficient mice with Staphylococcus aureus. Both TLR2- and MyD88-deficient mice were highly susceptible to S. aureus infection, with more enhanced susceptibility in MyD88-deficient mice. Peritoneal macrophages from MyD88-deficient mice did not produce any detectable levels of cytokines in response to S. aureus. In contrast, TLR2-deficient macrophages produced reduced, but significant, levels of the cytokines, and TLR4-deficient macrophages produced the same amounts as wild-type cells, indicating that S. aureus is recognized not only by TLR2, but also by other TLR family members except for TLR4.

In our opinion, all of the phenomena that are inhibited by cytochalasin can be thought of as resulting from contractile activity of cellular organelles. Smooth muscle contraction, clot retraction, beat of heart cells, and shortening of the tadpole tail are all cases in which no argument of substance for alternative causes can be offered. The morphogenetic processes in epithelia, contractile ring function during cytokinesis, migration of cells on a substratum, and streaming in plant cells can be explained most simply on the basis of contractility being the causal event in each process. The many similarities between the latter cases and the former ones in which contraction is certain argue for that conclusion. For instance, platelets probably contract, possess a microfilament network, and behave like undulating membrane organelles. Migrating cells possess undulating membranes and contain a similar network. It is very likely, therefore, that their network is also contractile. In all of the cases that have been examined so far, microfilaments of some type are observed in the cells; furthermore, those filaments are at points where contractility could cause the respective phenomenon. The correlations from the cytochalasin experiments greatly strengthen the case; microfilaments are present in control and "recovered" cells and respective biological phenomena take place in such cells; microfilaments are absent or altered in treated cells and the phenomena do not occur. The evidence seems overwhelming that microfilaments are the contractile machinery of nonmuscle cells. The argument is further strengthened if we reconsider the list of processes insensitive to cytochalasin (Table 2). Microtubules and their sidearms, plasma membrane, or synthetic machinery of cells are presumed to be responsible for such processes, and colchicine, membrane-active drugs, or inhibitors of protein synthesis are effective at inhibiting the respective phenomena. These chemical agents would not necessarily be expected to affect contractile apparatuses over short periods of time, they either do not or only secondarily interfere with the processes sensitive to cytochalasin (Table 1). It is particularly noteworthy in this context that microtubules are classed as being insensitive to cytochalasin and so are not considered as members of the "contractile microfilament" family. The overall conclusion is that a broad spectrum of cellular and developmental processes are caused by contractile apparatuses that have at least the common feature of being sensitive to cytochalasin. Schroeder's important insight (3) has, then, led to the use of cytochalasin as a diagnostic tool for such contracile activity: the prediction is that sensitivity to the drug implies presence of some type of contractile microfilament system. Only further work will define the limits of confidence to be placed upon such diagnoses. The basis of contraction in microfilament systems is still hypothetical. Contraction of glycerol-extracted cells in response to adenosine triphosphate (53), extraction of actin-like or actomyosin-like proteins from cells other than muscle cells (54), and identification of activity resembling that of the actomyosin-adenosine triphosphatase system in a variety of nonmuscle tissues (40, 54) are consistent with the idea that portions of the complex, striated muscle contractile system may be present in more primitive contractile machinery. In the case of the egg cortex, calcium-activated contractions can be inhibited by cytochalasin. If, as seems likely, microfilaments are the agents activated by calcium, then it will be clear that they have the same calcium requirement as muscle. Biochemical analyses of primitive contractile systems are difficult to interpret. Ishikawa's important observation (31), that heavy meromyosin complexes with fine filaments oriented parallel to the surface of chondrocytes and perpendicular to the surface of intestinal epithelial cells, implies that both types of filaments are "actin-like" in this one respect. Yet, it is very likely that these actin-like filaments correspond respectively to the cytochalasin-insensitive sheath of glial and heart fibroblasts and the core filaments of oviduct microvilli. No evidence from our studies links contractility directly to these meromyosin-binding filaments. Apart from this problem, activity resembling that of the myosin-adenosine triphosphatase has been associated with the microtubule systems of sperm tails and cilia (55), but those organelles are insensitive to cytochalasin in structure and function. Clearly, a means must be found to distinguish between enzymatic activities associated with microfilament networks, microfilament bundles, microtubules, and the sheath filaments of migratory cells. Until such distinctions are possible, little of substance can be said about the molecular bases of primitive contractile systems. Three variables are important for the control of cellular processes dependent upon microfilaments: (i) which cells of a population shall manufacture and assemble the filaments; (ii) where filaments shall be assembled in cells; and (iii) when contractility shall occur. With respect to distribution among cells, the networks involved in cell locomotion are presumed to be present in all cells that have the potential to move in cell culture. In this respect, the networks can be regarded as a common cellular organelle in the sense that cytoplasmic microtubules are so regarded. In some developing systems, all cells of an epithelium possess microfilament bundles (7, 13), whereas, in others, only discrete subpopulations possess the bundles (5, 6). In these cases the filaments can be regarded as being differentiation products associated only with certain cell types. These considerations may be related to the fact that microfilament networks are associated with behavior of individual cells (such as migration, wound healing, and cytokinesis), whereas the bundles are present in cells that participate in coordinated changes in shape of cell populations. With respect to placement in cells, two alternatives are apparent, namely, localized or ubiquitous association with the plasma membrane. Microfilament bundles of epithelial cells are only found extending across the luminal and basal ends of cells. In this respect they contrast with desmosomal tonofilaments and with microtubules, each of which can curve in a variety of directions through the cell. The strict localization of microfilament bundles probably rests upon their association with special junctional complex insertion regions that are only located near the ends of cells. In the case of mitotically active cells, the orientation of the spindle apparatus may determine the site at which the contractile ring of microfilaments will form (4, 56); this raises the question of what sorts of cytoplasmic factors can influence the process of association between filament systems and plasma membranes. In contrast to such cases of localized distribution, contractile networks responsible for cell locomotion are probably found beneath all of the plasma membrane, just as the network of thrombosthenin may extend to all portions of the periphery of a blood platelet. This ubiquitous distribution probably accounts for the ability of a fibroblast or glial cell to establish an undulating membrane at any point on its edge, or of an axon to form lateral microspikes along its length. The third crucial aspect of control of these contractile apparatuses involves the choice of when contraction shall occur (and as a corollary the degree or strength of contraction that will occur). In the simplest situation, contraction would follow automatically upon assembly of the microfilament bundles or networks. In cleavage furrows of marine embryos (4), for instance, microfilaments are seen beneath the central cleavage furrow and at its ends, but not beyond, under the portion of plasma membrane that will subsequently become part of the furrow. This implies that the furrow forms very soon after the contractile filaments are assembled in the egg cortex. In other cases, microfilaments are apparently assembled but not in a state of (maximal?) contraction. Thus, networks are seen along the sides of migratory cells, although such regions are not then active as undulating membrane organelles. Similarly, microfilament bundles occur in all epithelial cells of the salivary gland (13), or pancreatic anlage (7), although only the ones at discrete points are thought to generate morphogenetic tissue movements. Likewise, bundles begin to appear as early as 12 hours after estrogen administration to oviduct, although visible tubular gland formation does not start until 24 to 30 hours. Finally, streaming in plant cells can wax and wane, depending upon external factors such as auxin (57). All of these cases imply a control mechanism other than mere assembly of the microfilament systems and even raise the possibility that within one cell some filaments may be contracting while others are not. In discussing this problem, it must be emphasized that different degrees of contraction or relaxation cannot as yet be recognized with the electron microscope. In fact, every one of the cases cited above could be explained by contraction following immediately upon some subtle sort of "assembly." Inclusive in the latter term are relations between individual filaments, relations of the filaments and their insertion points on plasma membrane, and quantitative alterations in filament systems. Furthermore, the critical role of calcium and high-energy compounds in muscle contraction suggest that equivalent factors may be part of primitive, cytochalasinsensitive systems. The finding that calcium-induced contraction in the cortex of eggs is sensitive to cytochalasin strengthens that supposition and emphasizes the importance of compartmentalization of cofactors as a means of controlling microfilaments in cells.

A clone encoding PrP 27-30, the major protein in purified preparations of scrapie agent, was selected from a scrapie-infected hamster brain cDNA library by oligonucleotide probes corresponding to the N terminus of the protein. Southern blotting with PrP cDNA revealed a single gene with the same restriction patterns in normal and scrapie-infected brain DNA. A single PrP-related gene was also detected in murine and human DNA. PrP-related mRNA was found at similar levels in normal and scrapie-infected hamster brain, as well as in many other normal tissues. Using antisera against PrP 27-30, a PrP-related protein was detected in crude extracts of infected brain and to a lesser extent in extracts of normal brain. Proteinase K digestion yielded PrP 27-30 in infected brain extract, but completely degraded the PrP-related protein in normal brain extract. No PrP-related nucleic acids were found in purified preparations of scrapie prions, indicating that PrP 27-30 is not encoded by a nucleic acid carried within the infectious particles.

Yeast core telomeric heterochromatin can silence adjacent genes and requires RAP1, SIR2, SIR3, and SIR4 and histones H3 and H4 for this telomere position effect. SIR3 overproduction can extend the silenced domain. We examine here the nature of these multiprotein complexes. SIR2 and SIR4 were immunoprecipitated from whole-cell extracts. In addition, using formaldehyde cross-linking we have mapped SIR2, SIR4, and RAP1 along telomeric chromatin before and after SIR3 overexpression. Our data demonstrate that SIR2 and SIR4 interact in a protein complex and that SIR2, SIR3, SIR4, and RAP1 map to the same sites along telomeric heterochromatin in wild-type cells. However, when overexpressed, SIR3 spreads along the chromosome and its interactions are dominant to those of SIR4 and especially SIR2, whose detection is decreased in extended heterochromatin. RAP1 binding at the core region is unaffected by SIR3 overproduction and RAP1 shows no evidence of spreading. Thus, we propose that the structure of core telomeric heterochromatin differs from that extended by SIR3.

Comprehensive determination of the microbial composition of the gut microbiota and the relationships with health and disease are major challenges in the 21st century. Metagenomic analysis of the human gut microbiota detects mostly uncultured bacteria. We studied stools from two lean Africans and one obese European, using 212 different culture conditions (microbial culturomics), and tested the colonies by using mass spectrometry and 16S rRNA amplification and sequencing. In parallel, we analysed the same three samples by pyrosequencing 16S rRNA amplicons targeting the V6 region. The 32 500 colonies obtained by culturomics have yielded 340 species of bacteria from seven phyla and 117 genera, including two species from rare phyla (Deinococcus-Thermus and Synergistetes, five fungi, and a giant virus (Senegalvirus). The microbiome identified by culturomics included 174 species never described previously in the human gut, including 31 new species and genera for which the genomes were sequenced, generating c. 10 000 new unknown genes (ORFans), which will help in future molecular studies. Among these, the new species Microvirga massiliensis has the largest bacterial genome so far obtained from a human, and Senegalvirus is the largest virus reported in the human gut. Concurrent metagenomic analysis of the same samples produced 698 phylotypes, including 282 known species, 51 of which overlapped with the microbiome identified by culturomics. Thus, culturomics complements metagenomics by overcoming the depth bias inherent in metagenomic approaches.

BACKGROUND

The Global Burden of Disease Study 2013 (GBD 2013) aims to bring together all available epidemiological data using a coherent measurement framework, standardised estimation methods, and transparent data sources to enable comparisons of health loss over time and across causes, age-sex groups, and countries. The GBD can be used to generate summary measures such as disability-adjusted life-years (DALYs) and healthy life expectancy (HALE) that make possible comparative assessments of broad epidemiological patterns across countries and time. These summary measures can also be used to quantify the component of variation in epidemiology that is related to sociodemographic development.

METHODS

We used the published GBD 2013 data for age-specific mortality, years of life lost due to premature mortality (YLLs), and years lived with disability (YLDs) to calculate DALYs and HALE for 1990, 1995, 2000, 2005, 2010, and 2013 for 188 countries. We calculated HALE using the Sullivan method; 95% uncertainty intervals (UIs) represent uncertainty in age-specific death rates and YLDs per person for each country, age, sex, and year. We estimated DALYs for 306 causes for each country as the sum of YLLs and YLDs; 95% UIs represent uncertainty in YLL and YLD rates. We quantified patterns of the epidemiological transition with a composite indicator of sociodemographic status, which we constructed from income per person, average years of schooling after age 15 years, and the total fertility rate and mean age of the population. We applied hierarchical regression to DALY rates by cause across countries to decompose variance related to the sociodemographic status variable, country, and time.

RESULTS

Worldwide, from 1990 to 2013, life expectancy at birth rose by 6·2 years (95% UI 5·6-6·6), from 65·3 years (65·0-65·6) in 1990 to 71·5 years (71·0-71·9) in 2013, HALE at birth rose by 5·4 years (4·9-5·8), from 56·9 years (54·5-59·1) to 62·3 years (59·7-64·8), total DALYs fell by 3·6% (0·3-7·4), and age-standardised DALY rates per 100 000 people fell by 26·7% (24·6-29·1). For communicable, maternal, neonatal, and nutritional disorders, global DALY numbers, crude rates, and age-standardised rates have all declined between 1990 and 2013, whereas for non-communicable diseases, global DALYs have been increasing, DALY rates have remained nearly constant, and age-standardised DALY rates declined during the same period. From 2005 to 2013, the number of DALYs increased for most specific non-communicable diseases, including cardiovascular diseases and neoplasms, in addition to dengue, food-borne trematodes, and leishmaniasis; DALYs decreased for nearly all other causes. By 2013, the five leading causes of DALYs were ischaemic heart disease, lower respiratory infections, cerebrovascular disease, low back and neck pain, and road injuries. Sociodemographic status explained more than 50% of the variance between countries and over time for diarrhoea, lower respiratory infections, and other common infectious diseases; maternal disorders; neonatal disorders; nutritional deficiencies; other communicable, maternal, neonatal, and nutritional diseases; musculoskeletal disorders; and other non-communicable diseases. However, sociodemographic status explained less than 10% of the variance in DALY rates for cardiovascular diseases; chronic respiratory diseases; cirrhosis; diabetes, urogenital, blood, and endocrine diseases; unintentional injuries; and self-harm and interpersonal violence. Predictably, increased sociodemographic status was associated with a shift in burden from YLLs to YLDs, driven by declines in YLLs and increases in YLDs from musculoskeletal disorders, neurological disorders, and mental and substance use disorders. In most country-specific estimates, the increase in life expectancy was greater than that in HALE. Leading causes of DALYs are highly variable across countries.

CONCLUSIONS

Global health is improving. Population growth and ageing have driven up numbers of DALYs, but crude rates have remained relatively constant, showing that progress in health does not mean fewer demands on health systems. The notion of an epidemiological transition--in which increasing sociodemographic status brings structured change in disease burden--is useful, but there is tremendous variation in burden of disease that is not associated with sociodemographic status. This further underscores the need for country-specific assessments of DALYs and HALE to appropriately inform health policy decisions and attendant actions.

BACKGROUND

Bill & Melinda Gates Foundation.

Developing an evidence base for making public health decisions will require using data from evaluation studies with randomized and nonrandomized designs. Assessing individual studies and using studies in quantitative research syntheses require transparent reporting of the study, with sufficient detail and clarity to readily see differences and similarities among studies in the same area. The Consolidated Standards of Reporting Trials (CONSORT) statement provides guidelines for transparent reporting of randomized clinical trials. We present the initial version of the Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) statement. These guidelines emphasize the reporting of theories used and descriptions of intervention and comparison conditions, research design, and methods of adjusting for possible biases in evaluation studies that use nonrandomized designs.

Chromatin and transcriptional processes are among the most intensively studied fields of biology today. The introduction of chromatin immunoprecipitations (ChIP) represents a major advancement in this area. This powerful method allows researchers to probe specific protein-DNA interactions in vivo and to estimate the density of proteins at specific sites genome-wide. We have introduced several improvements to the traditional ChIP assay, which simplify the procedure, greatly reducing the time and labor required to complete the assay. The simplicity of the method yields highly reproducible results. Our improvements facilitate the probing of multiple proteins in a single experiment, which allows for the simultaneous monitoring of many genomic events. This method is particularly useful in kinetic studies where multiple samples are processed at the same time. Starting with sheared chromatin, PCR-ready DNA can be isolated from 16-24 ChIP samples in 4-6 h using the fast method.

The experiments reported here identify nitric oxide as a molecular effector of activated macrophage induced cytotoxicity. Cytotoxic activated macrophages synthesize nitric oxide from a terminal guanidino nitrogen atom of L-arginine which is converted to L-citrulline without loss of the guanidino carbon atom. In addition, authentic nitric oxide gas causes the same pattern of cytotoxicity in L10 hepatoma cells as is induced by cytotoxic activated macrophages (iron loss as well as inhibition of DNA synthesis, mitochondrial respiration, and aconitase activity). The results suggest that nitric oxide is the precursor of nitrite/nitrate synthesized by cytotoxic activated macrophages and, via formation of iron-nitric oxide complexes and subsequent degradation of iron-sulfur prosthetic groups, an effector molecule.

The structural dynamics of synapses probably has a crucial role in the development and plasticity of the nervous system. In the mammalian brain, the vast majority of excitatory axo-dendritic synapses occur on dendritic specializations called 'spines'. However, little is known about their long-term changes in the intact developing or adult animal. To address this question we developed a transcranial two-photon imaging technique to follow identified spines of layer-5 pyramidal neurons in the primary visual cortex of living transgenic mice expressing yellow fluorescent protein. Here we show that filopodia-like dendritic protrusions, extending and retracting over hours, are abundant in young animals but virtually absent from the adult. In young mice, within the 'critical period' for visual cortex development, approximately 73% of spines remain stable over a one-month interval; most changes are associated with spine elimination. In contrast, in adult mice, the overwhelming majority of spines (approximately 96%) remain stable over the same interval with a half-life greater than 13 months. These results indicate that spines, initially plastic during development, become remarkably stable in the adult, providing a potential structural basis for long-term information storage.

The discovery and analysis of community structure in networks is a topic of considerable recent interest within the physics community, but most methods proposed so far are unsuitable for very large networks because of their computational cost. Here we present a hierarchical agglomeration algorithm for detecting community structure which is faster than many competing algorithms: its running time on a network with n vertices and m edges is O (md log n) where d is the depth of the dendrogram describing the community structure. Many real-world networks are sparse and hierarchical, with m approximately n and d approximately log n, in which case our algorithm runs in essentially linear time, O (n log(2) n). As an example of the application of this algorithm we use it to analyze a network of items for sale on the web site of a large on-line retailer, items in the network being linked if they are frequently purchased by the same buyer. The network has more than 400 000 vertices and 2 x 10(6) edges. We show that our algorithm can extract meaningful communities from this network, revealing large-scale patterns present in the purchasing habits of customers.

Fluorodeoxyglucose positron emission tomography (PET) studies have found that patients with Alzheimer's dementia (AD) have abnormally low rates of cerebral glucose metabolism in posterior cingulate, parietal, temporal, and prefrontal cortex. We previously found that cognitively normal, late-middle-aged carriers of the apolipoprotein E epsilon4 allele, a common susceptibility gene for late-onset Alzheimer's dementia, have abnormally low rates of glucose metabolism in the same brain regions as patients with probable AD. We now consider whether epsilon4 carriers have these regional brain abnormalities as relatively young adults. Apolipoprotein E genotypes were established in normal volunteers 20-39 years of age. Clinical ratings, neuropsychological tests, magnetic resonance imaging, and PET were performed in 12 epsilon4 heterozygotes, all with the epsilon3/epsilon4 genotype, and 15 noncarriers of the epsilon4 allele, 12 of whom were individually matched for sex, age, and educational level. An automated algorithm was used to generate an aggregate surface-projection map that compared regional PET measurements in the two groups. The young adult epsilon4 carriers and noncarriers did not differ significantly in their sex, age, educational level, clinical ratings, or neuropsychological test scores. Like previously studied patients with probable AD and late-middle-aged epsilon4 carriers, the young epsilon4 carriers had abnormally low rates of glucose metabolism bilaterally in the posterior cingulate, parietal, temporal, and prefrontal cortex. Carriers of a common Alzheimer's susceptibility gene have functional brain abnormalities in young adulthood, several decades before the possible onset of dementia.

In order to investigate linkage detection strategies for genetically complex traits, multilocus models of inheritance need to be specified. Here, two types of multilocus model are described: (1) a multiplicative model, representing epistasis (interaction) among loci, and (2) an additive model, which is shown to closely approximate genetic heterogeneity, which is characterized by no interlocus interaction. A ratio lambda R of risk for type R relatives that is compared with population prevalence is defined. For a single-locus model, lambda R - 1 decreases by a factor of two with each degree of relationship. The same holds true for an additive multilocus model. For a multiplicative (epistasis) model, lambda R - 1 decreases more rapidly than by a factor of two with degree of relationship. Examination of lambda R values for various classes of relatives can potentially suggest the presence of multiple loci and epistasis. For example, data for schizophrenia suggest multiple loci in interaction. It is shown in the second paper of this series that lambda R is the critical parameter in determining power to detect linkage by using affected relative pairs.

Higher plants undergo a transition from a juvenile to an adult phase of vegetative development prior to flowering. Screens for mutants that undergo this transition precociously produced alleles of two genes required for posttranscriptional gene silencing (PTGS)--SUPPRESSOR OF GENE SILENCING3 (SGS3) and SUPPRESSOR OF GENE SILENCING2(SGS2)/SILENCING DEFECTIVE1 (SDE1)/RNA-DEPENDENT POLYMERASE6 (RDR6). Loss-of-function mutations in these genes have a phenotype similar to that of mutations in the Argonaute gene ZIPPY (ZIP). Epistasis analysis suggests that ZIP, SGS3, SGS2/SDE1/RDR6, and the putative miRNA export receptor, HASTY (HST), operate in the same pathway(s). Microarray analysis revealed a small number of genes whose mRNA is increased in ZIP, SGS3, and SGS2/SDE1/RDR6 mutants, as well as genes that are up-regulated in SGS3 and SGS2/SDE1/RDR6 mutants, but not in ZIP mutants. One of these latter genes (At5g18040) is silenced posttranscriptionally in trans by the sRNA255 family of endogenous, noncoding, small interfering RNAs (siRNAs). The increase in At5g18040 mRNA in SGS3 and SGS2/SDE1/RDR6 mutants is attributable to the absence of sRNA255-like siRNAs in these mutants. These results demonstrate a role for endogenous siRNAs in the regulation of gene expression, and suggest that PTGS plays a central role in the temporal control of shoot development in plants.

A study in vitro of specimens of human aortic and common carotid arteries was carried out to determine the feasibility of direct measurement (i.e., not from residual lumen) of arterial wall thickness with B mode real-time imaging. Measurements in vivo by the same technique were also obtained from common carotid arteries of 10 young normal male subjects. Aortic samples were classified as class A (relatively normal) or class B (with one or more atherosclerotic plaques). In all class A and 85% of class B arterial samples a characteristic B mode image composed of two parallel echogenic lines separated by a hypoechoic space was found. The distance between the two lines (B mode image of intimal + medial thickness) was measured and correlated with the thickness of different combinations of tunicae evaluated by gross and microscopic examination. On the basis of these findings and the results of dissection experiments on the intima and adventitia we concluded that results of B mode imaging of intimal + medial thickness did not differ significantly from the intimal + medial thickness measured on pathologic examination. With respect to the accuracy of measurements obtained by B mode imaging as compared with pathologic findings, we found an error of less than 20% for measurements in 77% of normal and pathologic aortic walls. In addition, no significant difference was found between B mode-determined intimal + medial thickness in the common carotid arteries evaluated in vitro and that determined by this method in vivo in young subjects, indicating that B mode imaging represents a useful approach for the measurement of intimal + medial thickness of human arteries in vivo.