Findings in ancient Egyptian mummies from tomb KV64, Valley of the Kings, Luxor, with evidence of a rheumatic disease.

OBJECTIVE: In 2011, a spectacular find was made in the Valley of the Kings, Egypt - a well-known archaeological site, where pharaohs were buried during the New Kingdom (ca. 1500-1100 BCE). A team from the University of Basel's Kings' Valley Project discovered a tomb (KV64) containing two mummies that were buried in different time episodes (unidentified elite burial, 18th dynasty, and Nehemesbastet, 22nd dynasty). METHOD: Anthropological investigations of the mummies were performed using portable X-ray and photographic documentation. RESULTS AND CONCLUSION: The first burial was an adult individual with bilateral pathological changes at the temporomandibular joints (TMJs), most likely of inflammatory origin, possibly psoriatic arthritis. Investigations of the second burial revealed an intact body of a younger female individual.

The application of a mathematical model linking structural and functional connectomes in severe brain injury.

Following severe injuries that result in disorders of consciousness, recovery can occur over many months or years post-injury. While post-injury synaptogenesis, axonal sprouting and functional reorganization are known to occur, the network-level processes underlying recovery are poorly understood. Here, we test a network-level functional rerouting hypothesis in recovery of patients with disorders of consciousness following severe brain injury. This hypothesis states that the brain recovers from injury by restoring normal functional connections via alternate structural pathways that circumvent impaired white matter connections. The so-called network diffusion model, which relates an individual's structural and functional connectomes by assuming that functional activation diffuses along structural pathways, is used here to capture this functional rerouting. We jointly examined functional and structural connectomes extracted from MRIs of 12 healthy and 16 brain-injured subjects. Connectome properties were quantified via graph theoretic measures and network diffusion model parameters. While a few graph metrics showed groupwise differences, they did not correlate with patients' level of consciousness as measured by the Coma Recovery Scale - Revised. There was, however, a strong and significant partial Pearson's correlation (accounting for age and years post-injury) between level of consciousness and network diffusion model propagation time (r = 0.76, p < 0.05, corrected), i.e. the time functional activation spends traversing the structural network. We concluded that functional rerouting via alternate (and less efficient) pathways leads to increases in network diffusion model propagation time. Simulations of injury and recovery in healthy connectomes confirmed these results. This work establishes the feasibility for using the network diffusion model to capture network-level mechanisms in recovery of consciousness after severe brain injury.

Ignition's glow: Ultra-fast spread of global cortical activity accompanying local "ignitions" in visual cortex during conscious visual perception.

Despite extensive research, the spatiotemporal span of neuronal activations associated with the emergence of a conscious percept is still debated. The debate can be formulated in the context of local vs. global models, emphasizing local activity in visual cortex vs. a global fronto-parietal "workspace" as the key mechanisms of conscious visual perception. These alternative models lead to differential predictions with regard to the precise magnitude, timing and anatomical spread of neuronal activity during conscious perception. Here we aimed to test a specific aspect of these predictions in which local and global models appear to differ - namely the extent to which fronto-parietal regions modulate their activity during task performance under similar perceptual states. So far the main experimental results relevant to this debate have been obtained from non-invasive methods and led to conflicting interpretations. Here we examined these alternative predictions through large-scale intracranial measurements (Electrocorticogram - ECoG) in 43 patients and 4445 recording sites. Both ERP and broadband high frequency (50-150 Hz - BHF) responses were examined through the entire cortex during a simple 1-back visual recognition memory task. Our results reveal short latency intense visual responses, localized first in early visual cortex followed (at ∼200 ms) by higher order visual areas, but failed to show significant delayed (300 ms) visual activations. By contrast, oddball image repeat events, linked to overt motor responses, were associated with a significant increase in a delayed (300 ms) peak of BHF power in fronto-parietal cortex. Comparing BHF responses with ERP revealed an additional peak in the ERP response - having a similar latency to the well-studied P3 scalp EEG response. Posterior and temporal regions demonstrated robust visual category selectivity. An unexpected observation was that high-order visual cortex responses were essentially concurrent (at ∼200 ms) with an ultra-fast spread of signals of lower magnitude that invaded selected sites throughout fronto-parietal cortical areas. Our results are compatible with local models in demonstrating a clear task-dependence of the 300 ms fronto-parietal activation. However, they also reveal a more global component of low-magnitude and poor content selectivity that rapidly spreads into fronto-parietal sites. The precise functional role of this global "glow" remains to be elucidated.

Expectancy-related modulations of neural oscillations in continuous performance tasks.

Analysis of neural oscillations in the electroencephalogram (EEG) during cognitive tasks provides valuable information about underlying neuronal processing not accessible by other methods such as event-related potentials (ERPs) and the BOLD signal in fMRI. We investigated neural substrates of motor preparation and expectancy by analyzing neural oscillations of healthy subjects performing the AX continuous performance task (AX-CPT), a task widely used to evaluate processes such as cognitive control, motor preparation and anticipatory and sustained attention. The task consists of letters presented sequentially on a monitor, and subjects are required to respond only when they see the letter A (cue) followed by the letter X (target). In this study, to emphasize expectation and motor preparation, three versions of AX-CPT were used in which the overall propensity to respond was differentially modulated, by changing the probability of the letter sequences. Neural activity was investigated in three time windows following presentation of the cue: sensory, evaluation and preparation. Alpha power was reduced following cue onset similarly in all versions of the task in both the sensory and evaluation periods, but in the later preparation period there were task dependent modulations. Alpha was decreased when an infrequent cue increased the chance of a response, and increased when a propensity to respond had to be overcome, possibly reflecting an anticipatory attentional mechanism to gate visuo-motor processing. Beta power was modulated by task and cue in both evaluation and preparation periods. In the latter, beta power reflected the propensity to respond and correlated both with amplitude of the contingent negative variation (CNV), an ERP that reflects response preparation, and with reaction time. Some clinical populations such as patients with schizophrenia or attention-deficit disorder show specific deficits when performing the AX-CPT. These results provide a basis for investigating the differential neural underpinnings of oscillatory cognitive control deficits observed in various patient populations.

Impaired attentional modulation of auditory evoked potentials in N-methyl-D-aspartate NR1 hypomorphic mice.

In human neurophysiology, auditory event-related potentials (AEPs) are used to investigate cognitive processes such as selective attention. Selective attention to specific tones causes a negative enhancement of AEPs known as processing negativity (PN), which is reduced in patients with schizophrenia. The evidence suggests that impaired selective attention in these patients may partially depend on deficient N-methyl-D-aspartate receptor (NMDAR)-mediated signaling. The goal of this study was to corroborate the involvement of the NMDAR in selective attention using a mouse model. To this end, we first investigated the presence of PN-like activity in C57BL/6J mice by recording AEPs during a fear-conditioning paradigm. Two alternating trains of tones, differing in stimulus duration, were presented on 7 subsequent days. One group received a mild foot shock delivered within the presentation of one train (conditioning train) on days 3-5 (conditioning days), while controls were never shocked. The fear-conditioned group (n= 9) indeed showed a PN-like activity during conditioning days manifested as a significant positive enhancement in the AEPs to the stimuli in the conditioning train that was not observed in the controls. The same paradigm was then applied to mice with reduced expression of the NMDAR1 (NR1) subunit and to a wild-type control group (each group n= 6). The NR1 mutants showed an associative AEP enhancement, but its magnitude was significantly reduced as compared with the magnitude in wild-type mice. We conclude that electrophysiological manifestations of selective attention are observable yet of different polarity in mice and that they require intact NMDAR-mediated signaling. Thus, deficient NMDAR functioning may contribute to abnormal selective attention in schizophrenia.

Underuse and overuse of diagnostic testing for coronary artery disease in patients presenting with new-onset chest pain.

PURPOSE: To determine the extent of overuse and underuse of diagnostic testing for coronary artery disease and whether the socioeconomic status, health insurance, gender, and race/ethnicity of a patient influences the use of diagnostic tests. SUBJECTS AND METHODS: We identified patients who presented with new-onset chest pain not due to myocardial infarction at one of five Los Angeles-area hospital emergency departments between October 1994 and April 1996. Explicit criteria for diagnostic testing were developed using the RAND/University of California, Los Angeles, expert panel method. They were applied to data collected by medical record review and patient questionnaire. RESULTS: Of the 356 patients, 181 met necessity criteria for diagnostic cardiac testing. Of these, 40 (22%) failed to receive necessary tests. Only 7 (3%) of the 215 patients who received some form of cardiac testing had tests that were judged to be inappropriate. Underuse was significantly more common in patients with only a high school education (30% vs 15% for those with some college, P = 0.02) and those without health insurance (34% vs 15% of insured patients, P = 0.01). In a multivariate logistic regression model, only the lack of a post-high school education was a significant predictor of underuse (odds ratio 2.2, 95% confidence interval 1.0 to 4.4). CONCLUSION: Among patients with new-onset chest pain, underuse of diagnostic testing for coronary artery disease was much more common than overuse. Underuse was primarily associated with lower levels of patient education.

Genetic interactions between mei-S332 and ord in the control of sister-chromatid cohesion.

The Drosophila mei-S332 and ord gene products are essential for proper sister-chromatid cohesion during meiosis in both males and females. We have constructed flies that contain null mutations for both genes. Double-mutant flies are viable and fertile. Therefore, the lack of an essential role for either gene in mitotic cohesion cannot be explained by compensatory activity of the two proteins during mitotic divisions. Analysis of sex chromosome segregation in the double mutant indicates that ord is epistatic to mei-S332. We demonstrate that ord is not required for MEI-S332 protein to localize to meiotic centromeres. Although overexpression of either protein in a wild-type background does not interfere with normal meiotic chromosome segregation, extra ORD+ protein in mei-S332 mutant males enhances nondisjunction at meiosis II. Our results suggest that a balance between the activity of mei-S332 and ord is required for proper regulation of meiotic cohesion and demonstrate that additional proteins must be functioning to ensure mitotic sister-chromatid cohesion.

Maintenance of sister-chromatid cohesion at the centromere by the Drosophila MEI-S332 protein.

Sister-chromatid cohesion is essential for the faithful segregation of chromosomes during cell division. Recently biochemical analysis with Xenopus extracts suggests that cohesion is established during S phase by a cohesion complex but that other proteins must maintain it in mitosis. The Drosophila melanogaster MEI-S332 protein is present on centromeres in mitosis and meiosis and is essential for cohesion at the centromeres in meiosis II. Here, we analyze the timing of MEI-S332 assembly onto centromeres and the functional domains of the MEI-S332 protein. We find that MEI-S332 is first detectable on chromosomes during prometaphase, and this localization is independent of microtubules. MEI-S332 contains two separable functional domains, as mutations within these domains show intragenic complementation. The carboxy-terminal basic region is required for chromosomal localization. The amino-terminal coiled-coil domain may facilitate protein-protein interactions between MEI-S332 and male meiotic proteins. MEI-S332 interacts with itself in the yeast two-hybrid assay and in immunoprecipitates from Drosophila oocyte and embryo extracts. Thus it appears that MEI-S332 assembles into a multimeric protein complex that localizes to centromeric regions during prometaphase and is required for the maintenance of sister-chromatid cohesion until anaphase, rather than its establishment in S phase.

Control of amino acid permease sorting in the late secretory pathway of Saccharomyces cerevisiae by SEC13, LST4, LST7 and LST8.

The SEC13 gene was originally identified by temperature-sensitive mutations that block all protein transport from the ER to the Golgi. We have found that at a permissive temperature for growth, the sec13-1 mutation selectively blocks transport of the nitrogen-regulated amino acid permease, Gap1p, from the Golgi to the plasma membrane, but does not affect the activity of constitutive permeases such as Hip1p, Can1p, or Lyp1p. Different alleles of SEC13 exhibit different relative effects on protein transport from the ER to the Golgi, or on Gap1p activity, indicating distinct requirements for SEC13 function at two different steps in the secretory pathway. Three new genes, LST4, LST7, and LST8, were identified that are also required for amino acid permease transport from the Golgi to the cell surface. Mutations in LST4 and LST7 reduce the activity of the nitrogen-regulated permeases Gap1p and Put4p, whereas mutations in LST8 impair the activities of a broader set of amino acid permeases. The LST8 gene encodes a protein composed of WD-repeats and has a close human homologue. The LST7 gene encodes a novel protein. Together, these data indicate that SEC13, LST4, LST7, and LST8 function in the regulated delivery of Gap1p to the cell surface, perhaps as components of a post-Golgi secretory-vesicle coat.

Mutational analysis of the Drosophila sister-chromatid cohesion protein ORD and its role in the maintenance of centromeric cohesion.

The ord gene is required for proper segregation of all chromosomes in both male and female Drosophila meiosis. Here we describe the isolation of a null ord allele and examine the consequences of ablating ord function. Cytologically, meiotic sister-chromatid cohesion is severely disrupted in flies lacking ORD protein. Moreover, the frequency of missegregation in genetic tests is consistent with random segregation of chromosomes through both meiotic divisions, suggesting that sister cohesion may be completely abolished. However, only a slight decrease in viability is observed for ord null flies, indicating that ORD function is not essential for cohesion during somatic mitosis. In addition, we do not observe perturbation of germ-line mitotic divisions in flies lacking ORD activity. Our analysis of weaker ord alleles suggests that ORD is required for proper centromeric cohesion after arm cohesion is released at the metaphase I/anaphase I transition. Finally, although meiotic cohesion is abolished in the ord null fly, chromosome loss is not appreciable. Therefore, ORD activity appears to promote centromeric cohesion during meiosis II but is not essential for kinetochore function during anaphase.

Holding chromatids together to ensure they go their separate ways.

Association between sister chromatids is essential for their attachment and segregation to opposite poles of the spindle in mitosis and meiosis II. Sister-chromatid cohesion is also likely to be involved in linking homologous chromosomes together in meiosis I. Cytological observations provide evidence that attachment between sister chromatids is different in meiosis and mitosis and suggest that cohesion between the chromatid arms may differ mechanistically from that at the centromere. The physical nature of cohesion is addressed, and proteins that are candidates for holding sister chromatids together are discussed. Dissolution of sister-chromatid cohesion must be regulated precisely, and potential mechanisms to release cohesion are presented.

Identification of ORD, a Drosophila protein essential for sister chromatid cohesion.

Attachment between the sister chromatids is required for proper chromosome segregation in meiosis and mitosis, but its molecular basis is not understood. Mutations in the Drosophila ord gene result in premature sister chromatid separation in meiosis, indicating that the product of this gene is necessary for sister chromatid cohesion. We isolated the ord gene and found that it encodes a novel 55 kDa protein. Some of the ord mutations exhibit unusual complementation properties, termed negative complementation, in which particular alleles poison the activity of another allele. Negative complementation predicts that protein-protein interactions are critical for ORD function. The position and nature of these unusual ord mutations demonstrate that the C-terminal half of ORD is essential for sister chromatid cohesion and suggest that it mediates protein binding.

Health for all in the Republic of Korea: one country's experience with implementing universal health care.

Health care reforms in many countries face the twin challenges of providing universal coverage while controlling spiraling costs. Sixteen years ago the Republic of Korea had no national plan for health insurance, and only 8.8% of the population was covered. In 1975, health care accounted for 2.8% of GDP with government providing 12% of the finances. In 1977, Korea adopted a policy designed to achieve universal coverage while maintaining fee-for-service reimbursement. Korea incrementally established an employer based health care scheme by first mandating coverage for businesses, then government employees and teachers. Coverage was later extended to the poor, the self-employed, and residents of rural areas. Independent insurance societies manage each scheme, set premiums and co-payments, and are responsible for maintaining financial viability. By 1991, 30% of Korea's health care expenditures were from public funds, and health care costs had risen to 7.1% of GDP. Health care reform in Korea has been successful in achieving universal coverage, providing for a full range of services, and eliminating adverse selection. The system is financially solvent, costs are equitably distributed with the government providing subsidies when necessary, and small businesses have not been unduly burdened economically. Attempts to limit costs, however, have been unsuccessful. Patient demand for health care has remained surprisingly resistant to increasing co-payments. Providers have responded to lower physician and hospital fees by providing shorter, more frequent patient visits, relabeling services, and increasing hospital admissions. Competition between insurance societies has not materialized in a meaningful way to control costs.

Self-association of the Drosophila zeste protein is responsible for transvection effects.

The zeste gene product is required for transvection effects that imply the ability of regulatory elements on one chromosome to affect the expression of the homologous gene in a somatically paired chromosome. The z1 mutation causes a pairing dependent inhibition of the expression of the white gene. Both of these phenomena can be explained by the tendency of zeste protein, expressed in bacteria or in flies, to self-associate, forming complexes of several hundred monomers. These large aggregates bind to DNA and are found in nuclear matrix preparations, probably because they co-sediment with the matrix. The principal determinants of this self-association are located in the C-terminal half of the protein but some limited aggregation is obtained also with the N-terminal half, which contains the DNA binding domain. The z1 and zop2 mutant proteins aggregate to the same degree as the wild type but the z11G3 product, a pseudorevertant of z1, has a reduced tendency to aggregate. This mutation, which in vivo is antagonistic to z1 and does not support transvection effects, can be made to revert its phenotype when the mutant protein is over-produced under the control of the heat shock promoter. These results indicate that both the zeste-white interaction and transvection effects require the formation of high order aggregates. When the z1 protein is over-produced in vivo, it reduces the expression of an unpaired copy of white, indicating that the normal requirement for chromosome pairing is simply a device to increase the size of the aggregate bound to the white regulatory region.

Developmental expression of the Drosophila zeste gene and localization of zeste protein on polytene chromosomes.

The expression of the zeste gene varies through the life cycle of the fly. Its transcription is most abundant in maternal RNA, declines to very low levels during larval growth, but rises again in late third instar larvae and pupae. Using transposons containing a zeste-lacZ gene, we found a corresponding variation in the tissue distribution of zeste from stage to stage. Nearly ubiquitous expression of the zeste-lacZ gene is found in late embryos and first instar larvae, but disappears almost completely except in brain and gonads by third instar larva. Shortly before pupation expression rises again in imaginal discs, Malpighian tubules, and salivary glands and again becomes nearly ubiquitous in pupae. zeste continues to be expressed in adult brain and gonads. We constructed flies carrying a zeste gene controlled by the heat shock promoter and studied the distribution of zeste protein in their polytene chromosomes as well as those of wild-type flies. Using affinity-purified anti-zeste antibodies, we find that wild-type salivary gland chromosomes contain about 60 strong bands of zeste immunofluorescence at specific cytological locations. After heat induction of larvae containing the hs-zeste gene, many hundreds of bands appear. These results suggest the involvement of zeste in the expression of a wide variety of genes at different developmental stages.

Zeste encodes a sequence-specific transcription factor that activates the Ultrabithorax promoter in vitro.

Zeste is a Drosophila regulatory gene that is required for transvection at the bithorax complex. Here we find that purified zeste protein binds to multiple sites just 5' of the initiation site of Ubx RNA. Zeste protein purified from Drosophila cells or from E. coli expressing the zeste gene activates Ubx transcription in vitro. This activation is dependent on the presence of zeste protein binding sites, as it is not observed with a Ubx promoter lacking these sites or with an Adh promoter. These results suggest that transvection involves regulatory elements that act at the level of transcriptional initiation and may be mechanistically similar to activation of transcription by enhancer elements, except that transvection occurs across paired chromosomes. These findings are consistent with the hypothesis that zeste may play a more important role in the normal regulation of Ubx and its other target genes than current genetic evidence implies.