COVID-19 Testing Among Out-of-Hospital Cardiac Arrest Patients: Implications for Public Health.

OBJECTIVE: The objective of this study was to compare COVID-19 test positivity among out-of-hospital cardiac arrest patients whose resuscitative efforts were terminated in the field with the surrounding community. METHODS: This was a retrospective cohort study of out-of-hospital cardiac arrest patients for whom unsuccessful resuscitative efforts were terminated in the field. Emergency medical services (EMS) personnel obtained postmortem COVID-19 nasal swab specimens from these patients between July 1, 2020 and February 28, 2022 to facilitate patient contact tracing and awareness of potential occupational exposure. A chi-square (n-1) was used to compare test result proportions between cardiac arrest patients and the community at large. A Pearson correlation was used to correlate test positivity among the two groups. RESULTS: EMS personnel obtained postmortem specimens from 648 cardiac arrest patients; 20 (3.1%) were inconclusive. Of the 628 specimens successfully tested, 69 (11.0%) were positive, and 559 (89.0%) were negative. Monthly positivity ranged from 0.0% to 34.0%. For the community at large, overall test positivity during the same period was 5.1%, with a monthly range from 0.4% to 15.2%. Overall, expired and tested cardiac arrest patients had 5.9% (95%CI 3.68 - 8.59) greater COVID-19 test positivity than the general community. There was significant correlation in monthly positivity rates between the groups (r = 0.778, p < .001, 95%CI0.51 - 0.91). CONCLUSIONS: Compared to the general population, COVID-19 was over-represented among EMS cardiac arrest patients who died in the field. Postmortem testing by EMS personnel, not typical practice, identified infectious disease cases that would have otherwise gone undetected, indicating potential for future surveillance applications.

An EMS Transport Destination Officer is Associated with Reductions in Simultaneous Emergency Department Arrivals.

Objective: A centralized transport destination officer (TDO) is one technique used by EMS systems to distribute patients. This retrospective analysis examines the effect of a TDO on simultaneous arrivals and consecutive simultaneous arrivals at emergency departments in a suburban EMS system, and their relationship to transport unit throughput.Methods: Each system hospital arrival from July 1, 2020 to February 28, 2022, at six study hospitals was evaluated. An arrival within 300 seconds of the previous arrival at the same hospital was designated as a simultaneous arrival. Any simultaneous arrival where the previous arrival was also a simultaneous arrival was further designated as a consecutive simultaneous arrival. Simultaneous and consecutive simultaneous arrivals were aggregated by day to produce countywide daily totals. Median and interquartile ranges were calculated and a Wilcoxon rank-sum test was used to compare each outcome, with the presence of the TDO as the grouping variable. A Pearson correlation was used to assess the relationship between daily total simultaneous and consecutive simultaneous arrivals to median daily hospital turnaround interval.Results: Median simultaneous arrivals showed a 15% reduction from 21 [IQR: 17 - 26] to 18 [IQR: 15 - 22] (p < 0.001). Consecutive simultaneous arrivals decreased 33%, from 6 [IQR: 4 - 9] to 4 per day [IQR: 2 - 6] on days when the TDO was in place (p < 0.001). Increased total daily simultaneous and consecutive simultaneous arrivals also showed statistically significant correlation with increased median daily hospital turnaround interval (simultaneous r = 0.488, p < 0.001; consecutive simultaneous r = 0.360 p < 0.001).Conclusions: A centralized EMS transport destination officer is associated with a reduction in simultaneous and consecutive simultaneous arrivals of patients in the emergency department. Further analysis also shows a significant correlation between the number of simultaneous and consecutive simultaneous arrivals and transport unit hospital turnaround interval. This technique to achieve load balancing across transport destinations appears to be effective and can be considered in systems experiencing throughput difficulties.

Decreases in out of hospital cardiac arrest (OHCA) outcome metrics persist when known COVID patients are excluded from analysis.

OBJECTIVE: A decline in OHCA performance metrics during the pandemic has been reported in the literature but the cause is still not known. The Montgomery County Fire and Rescue Service (MCFRS) observed a decline in both the rate of return of spontaneous circulation (ROSC) and the proportion of resuscitations that resulted in cerebral performance category (CPC) 1 or 2 discharge of the patient beginning in March of 2020. This study examines whether the decline in these performance metrics persists when known COVID positive patients are excluded from the analysis. METHODS: Two samples of OHCA patients for similar time periods (one year apart) before and after the start of the COVID pandemic were developed. A database of known COVID positive patients among EMS encounters was used to identify and exclude COVID positive patients. OHCA outcomes in these two groups were then compared using a Chi-square test and Fisher's exact test for difference in proportions and Analysis of Variance (ANOVA) for difference in means. A two-stage multivariable logistic regression model was used to develop odds ratios for achieving ROSC and CPC 1 or 2 discharge in each period. RESULTS: After excluding known COVID patients, 32.5% of the patients in the pre-COVID period achieved ROSC compared to 25.1% in the COVID period (p = 0.007). 6% of patients in the pre-COVID period were discharged with CPC 1 or 2 compared to 3.2% from the COVID era (p = 0.026). Controlling for all available patient characteristics, patients undergoing OHCA resuscitation prior to be beginning of the pandemic were 1.2 times more likely to achieve ROSC and 1.6 times more likely to be discharged with CPC 1 or 2 than non-COVID patients in the pandemic era sample. CONCLUSIONS: When known COVID patients are excluded, pre-pandemic OHCA resuscitation patients were more likely to achieve ROSC and CPC 1 or 2 discharge. The prevalence of known COVID positive patients among all OHCA resuscitations during the pandemic was not sufficient to fully account for the marked decrease in both ROSC and CPC 1 or 2 discharges. Other causative factors must be sought.

A Statewide EMS Viral Syndrome Pandemic Triage Protocol: 24 Hour Outcomes.

Background: Early during the COVID-19 pandemic, Emergency Medical Services (EMS) systems encountered many challenges that prompted crisis-level strategies. Maryland's statewide EMS system implemented the Viral Syndrome Pandemic Triage Protocol which contained a decision tool to help identify patients potentially safe for self-care at home. Objectives: This study assessed the effects of the Maryland Viral Syndrome Pandemic Triage Protocol and the safety of referring patients for self-care at home. Methods: This is a retrospective statewide analysis of EMS patients from March 19 thru September 4, 2020, who were not transported and had documentation of the Viral Syndrome Pandemic Triage Protocol's decision support tool completed, as well as a random sample of 150 patients who were not transported and did not have documentation of the decision tool. Descriptive statistics were performed as well as a two-stage multivariable logistic regression model for the outcomes of ED presentation within 24 hours and subsequent hospitalization. Results: 301 EMS patients were documented as triaged to home using the protocol and outcomes data were available for 282 (94%). 41(14.5%) patients presented to an ED within 24 hours and 14 (5% of 282) required inpatient hospitalization. Nine (3.2%) patients were subsequently hospitalized with a diagnosis of COVID-19 illness. Of those patients for whom the decision tool was not documented, 35 (23%) had an ED visit within 24 hours and 15 (10%) were hospitalized (p = 0.075). Multivariate logistic regression model results (N = 432) suggest that those with documentation of triage protocol use had some advantage over those patients without documentation. The 95% CIs of the estimated effect of Triage/No Triage protocol documented were wide and crossed the 1.0 limit but overall, all effects Odds Ratios and Adjust Odds Ratios were consistently over 1.0 with the lowest value of 1.3 and the highest value of 2.1. Conclusion: Most patients (95%) who were triaged to self-care at home with home documented decision support tool use did not require hospitalization within 24 hours following EMS encounter and this appears to be safe. Future opportunity exists to incorporate such tools into comprehensive pandemic preparedness strategies along with appropriate follow up and quality improvement mechanisms.

Vapour pressure deficit determines critical thresholds for global coffee production under climate change.

Our understanding of the impact of climate change on global coffee production is largely based on studies focusing on temperature and precipitation, but other climate indicators could trigger critical threshold changes in productivity. Here, using generalized additive models and threshold regression, we investigate temperature, precipitation, soil moisture and vapour pressure deficit (VPD) effects on global Arabica coffee productivity. We show that VPD during fruit development is a key indicator of global coffee productivity, with yield declining rapidly above 0.82 kPa. The risk of exceeding this threshold rises sharply for most countries we assess, if global warming exceeds 2 °C. At 2.9 °C, countries making up 90% of global supply are more likely than not to exceed the VPD threshold. The inclusion of VPD and the identification of thresholds appear critical for understanding climate change impacts on coffee and for the design of adaptation strategies.

The effect of daclizumab on brain atrophy in relapsing-remitting multiple sclerosis.

Daclizumab is a monoclonal antibody that reduces inflammation in multiple sclerosis (MS). Through a retrospective analysis, our objective was to determine whether daclizumab treatment reduces the rate of brain structure atrophy in comparison to a mixture of other disease-modifying therapies (mainly different interferon ß preparations). We analyzed MRI examinations (1332 scans from 70 MS cases) obtained between 2000 and 2011 in a single center and processed with an automated brain segmentation method. We used mixed-effects multivariable linear regression models to determine whether a median of 4.3 years of daclizumab therapy in 26 patients altered rates of brain-volume change, controlling for variations in MRI protocol. The control group consisted of 44 patients not treated with daclizumab. We found that supratentorial brain volume declined by 5.17 ml per year (95% confidence limits: 3.58-6.77) off daclizumab therapy. On daclizumab, the annual rate of volume loss decreased to 3.72 ml (p=0.01). The rate of ventricular enlargement decreased from 1.26 to 0.42 ml per year (p<0.001). Focused analysis suggests that reduction in gray matter atrophy rate most likely underlies these results. In summary, in this retrospective analysis, daclizumab therapy substantially decreased the rate of brain atrophy in relapsing-remitting MS in comparison to other disease-modifying therapies, predominantly interferon ß.

Evolution of the blood-brain barrier in newly forming multiple sclerosis lesions.

OBJECTIVE: Multiple sclerosis (MS) lesions develop around small, inflamed veins. New lesions enhance with gadolinium on magnetic resonance imaging (MRI), reflecting disruption of the blood-brain barrier (BBB). Single time point results from pathology and standard MRI cannot capture the spatiotemporal expansion of lesions. We investigated the development and expansion of new MS lesions, focusing on the dynamics of BBB permeability. METHODS: We performed dynamic contrast-enhanced (DCE) MRI in relapsing-remitting MS. We obtained data over 65 minutes, during and after gadolinium injection. We labeled spatiotemporal enhancement dynamics as centrifugal when initially central enhancement expanded outward and centripetal when initially peripheral enhancement gradually filled the center. RESULTS: We detected 34 enhancing lesions in 200 DCE-MRI scans. In 65%, enhancement first appeared as a closed ring; in 18%, as a nodule; and in 18%, as an open ring. Lesions with initially nodular enhancement were smaller than those initially enhancing as rings (p < 0.0001). All initially nodular lesions enhanced centrifugally, whereas initially ringlike lesions enhanced centripetally, becoming nodular if small (82%) or nearly nodular if larger (18%). Open-ring lesions were periventricular or juxtacortical and enhanced centripetally. Centrifugally enhancing lesions evolved into centripetally enhancing lesions over several days. INTERPRETATION: The rapid change of enhancement dynamics from centrifugal to centripetal reflects the outward growth of MS lesions around their central vein and suggests that factors mediating lesion growth and tissue repair derive from different locations at different times. We propose a model of new lesion growth that unites our imaging observations with existing pathology data.

Cerebrospinal fluid evidence of increased extra-mitochondrial glucose metabolism implicates mitochondrial dysfunction in multiple sclerosis disease progression.

In contrast to relapse, the mechanisms of multiple sclerosis (MS) disease progression are less understood and appear not to be exclusively inflammatory in nature. In this pilot study we investigated the relationship between disturbed CNS energy metabolism and MS disease progression. We tested the hypothesis that cerebrospinal fluid (CSF) concentrations of sorbitol, fructose, and lactate, all metabolites of extra-mitochondrial glucose metabolism, would be elevated in secondary progressive (SP) MS patients and would be associated with worsening neurologic disability. We measured metabolite concentrations by gas chromatographic/mass spectrometric and enzymatic methods in archived CSF samples from 85 MS patients [31 relapsing-remitting (RR) and 54 SP patients] and 18 healthy controls. We found that concentrations of all three metabolites, but not concentrations of glucose or myoinositol, were significantly increased in CSF from SP and, to a lesser degree, RR patients, compared to controls. Furthermore, CSF concentrations of sorbitol and fructose (polyol pathway metabolites), but not lactate (anaerobic glycolysis metabolite), correlated positively and significantly with Expanded Disability Status Scale (EDSS) score, an index of neurologic disability in MS patients. We conclude that extra-mitochondrial glucose metabolism is increased in MS patients and is associated with disease progression evidenced by increasing EDSS score. As extra-mitochondrial glucose metabolism increases with impaired mitochondrial metabolism of glucose, these findings implicate mitochondrial dysfunction in the pathogenesis of MS disease progression. CSF metabolic profiling may be useful in clarifying the role of mitochondrial pathology in progression and in targeting and monitoring therapies for disease progression that aim to preserve or boost mitochondrial glucose metabolism.

Strategies to improve sleep during extended search and rescue operations.

OBJECTIVE: This study investigated strategies to improve sleeping conditions during search and rescue operations during disaster response. METHODS: Forty members of the Montgomery County (Maryland) Urban Search and Rescue Team were surveyed for individual sleep habits and sleeping aids used during extended deployments. Team members were also asked to suggest methods to improve sleep on future deployments. RESULTS: The average amount of sleep during field operations was 5.4 hours with a range of 4-8 hours. Eight percent surveyed would prefer another schedule besides the 12-hour work day, all of whom proposed three 8-hour shifts. Fifteen percent of participants were interested in a pharmacological sleeping aid. Fifty percent of search and rescue members interviewed would consider using nonpharmacological sleeping aids. Furthermore, 40% of participants stated they had successfully devised self-employed methods of sleep aids for previous deployments, such as ear plugs, massage, mental imagery, personal routines, music and headphones, reading, and blindfolds. CONCLUSIONS: This study suggests that availability of both pharmacological and nonpharmacological sleeping aids to search and rescue workers via the team cache could impact the quantity of sleep. Further investigation into methods of optimizing sleep during field missions could theoretically show enhanced performance through various aspects of missions including mitigation of errors, improved productivity, and improved overall physiological and emotional well-being of search and rescue personnel.

Using improved technology for filter paper-based blood collection to survey wild Sika deer for antibodies to hepatitis E virus.

Recent reports from Japan implicated wild Sika deer (Cervus nippon) in the zoonotic transmission of hepatitis E to humans. Seroprevalence studies were performed to determine if imported feral populations of Sika deer in Maryland and Virginia posed a similar risk of transmitting hepatitis E virus (HEV). Hunters collected blood on filter paper discs from freshly killed deer. The discs were desiccated and delivered to a collection point. The dried filters were weighed to estimate the amount of blood absorbed and were eluted and collected in one tube via a novel extraction system. The procedure was quantified and validated with negative and positive serum and blood samples obtained from domestic Sika deer before and after immunization with HEV recombinant capsid protein, respectively. None of the 155 tested samples contained antibody to HEV, suggesting that Sika deer in these populations, unlike those in Japan, do not pose a significant zoonotic threat for hepatitis E. However, the new method developed for collecting and eluting the samples should prove useful for field studies of many other pathogens.

Conventional magnetic resonance imaging features in patients with tropical spastic paraparesis.

Conventional brain and spinal cord magnetic resonance images were performed in 21 patients with human T-cell lymphotropic virus (HTLV)-1 associated myelopathy/tropical spastic paraparesis, to assess the role of conventional magnetic resonance imaging (MRI) in the disease diagnosis. These patients had no other central nervous system conditions or related risk factors at the time of tropical spastic paraparesis diagnosis. Eleven (52.4%) patients showed nonspecific brain abnormalities on T2-weighted images. The majority (77.2%) of brain abnormalities were located in the deep white matter. A transient contrast-enhancing lesion was identified in the brain of only one patient. In the brain of another patient, 9.0% of the T2-hyperintense lesion load was hypointense on the correspondent T1-weighted images. No differences in terms of demographic, biological, or clinical variables were present between patients with abnormal brain images and those with normal brain magnetic resonance images. Spinal cord T2-weighted images were abnormal in three (14.3%) patients. In one of these three patients, a diffuse but transient edema was found along the entire tract of the spinal cord. White matter lesions were present in the central nervous system of 60% of the cases in this study. However, no correlations between magnetic resonance imaging and clinical findings, and no specificity of lesions were observed. Hence, conventional magnetic resonance imaging is a sensitive but not highly specific tool for diagnosis of tropical spastic paraparesis.

Effects of interferon beta-1b on black holes in multiple sclerosis over a 6-year period with monthly evaluations.

BACKGROUND: Chronic, hypointense black holes (BHs) are recognized as a sign of permanent damage in patients with multiple sclerosis. Although the effects of interferon beta-1b in reducing the formation of new BHs are established, it is not clear whether the drug may reduce BH duration after these lesions are formed. OBJECTIVE: To analyze the effects of interferon beta-1b in reducing the duration of T1 BHs in patients with multiple sclerosis. DESIGN: Patients were clinically assessed and imaged monthly over a 36-month natural history phase and 36-month therapy phase. Numbers of contrast-enhanced lesions and newly formed BHs were counted on each scan. Each BH was counted until it was no longer seen. SETTING: Outpatient service of the Neuroimmunology Branch at the National Institutes of Health, Bethesda, Md. PATIENTS: Six patients with relapsing-remitting multiple sclerosis were included. One patient did not form any BHs during the therapy phase. Analyses were performed on the remaining 5 individuals. INTERVENTIONS: Interferon beta-1b at the dosage of 8 million international units every other day. MAIN OUTCOME MEASURES: Number and duration (in months) of newly formed BHs. RESULTS: Rate of BH accumulation decreased with treatment (P = .01), but Kaplan-Meier models revealed that the duration of BHs did not shorten (chi2(1) = 2.47, P = .12). CONCLUSIONS: Interferon beta-1b reduces the frequency of new BH formation but does not appear to decrease their duration in time. Analyses with larger patient cohorts are needed to confirm these preliminary findings.

Linkage mapping bovine EST-based SNP.

BACKGROUND: Existing linkage maps of the bovine genome primarily contain anonymous microsatellite markers. These maps have proved valuable for mapping quantitative trait loci (QTL) to broad regions of the genome, but more closely spaced markers are needed to fine-map QTL, and markers associated with genes and annotated sequence are needed to identify genes and sequence variation that may explain QTL. RESULTS: Bovine expressed sequence tag (EST) and bacterial artificial chromosome (BAC)sequence data were used to develop 918 single nucleotide polymorphism (SNP) markers to map genes on the bovine linkage map. DNA of sires from the MARC reference population was used to detect SNPs, and progeny and mates of heterozygous sires were genotyped. Chromosome assignments for 861 SNPs were determined by twopoint analysis, and positions for 735 SNPs were established by multipoint analyses. Linkage maps of bovine autosomes with these SNPs represent 4585 markers in 2475 positions spanning 3058 cM. Markers include 3612 microsatellites, 913 SNPs and 60 other markers. Mean separation between marker positions is 1.2 cM. New SNP markers appear in 511 positions, with mean separation of 4.7 cM. Multi-allelic markers, mostly microsatellites, had a mean (maximum) of 216 (366) informative meioses, and a mean 3-lod confidence interval of 3.6 cM Bi-allelic markers, including SNP and other marker types, had a mean (maximum) of 55 (191) informative meioses, and were placed within a mean 8.5 cM 3-lod confidence interval. Homologous human sequences were identified for 1159 markers, including 582 newly developed and mapped SNP. CONCLUSION: Addition of these EST- and BAC-based SNPs to the bovine linkage map not only increases marker density, but provides connections to gene-rich physical maps, including annotated human sequence. The map provides a resource for fine-mapping quantitative trait loci and identification of positional candidate genes, and can be integrated with other data to guide and refine assembly of bovine genome sequence. Even after the bovine genome is completely sequenced, the map will continue to be a useful tool to link observable phenotypes and animal genotypes to underlying genes and molecular mechanisms influencing economically important beef and dairy traits.

Operational seasonal forecasting of crop performance.

Integrated, interdisciplinary crop performance forecasting systems, linked with appropriate decision and discussion support tools, could substantially improve operational decision making in agricultural management. Recent developments in connecting numerical weather prediction models and general circulation models with quantitative crop growth models offer the potential for development of integrated systems that incorporate components of long-term climate change. However, operational seasonal forecasting systems have little or no value unless they are able to change key management decisions. Changed decision making through incorporation of seasonal forecasting ultimately has to demonstrate improved long-term performance of the cropping enterprise. Simulation analyses conducted on specific production scenarios are especially useful in improving decisions, particularly if this is done in conjunction with development of decision-support systems and associated facilitated discussion groups. Improved management of the overall crop production system requires an interdisciplinary approach, where climate scientists, agricultural scientists and extension specialists are intimately linked with crop production managers in the development of targeted seasonal forecast systems. The same principle applies in developing improved operational management systems for commodity trading organizations, milling companies and agricultural marketing organizations. Application of seasonal forecast systems across the whole value chain in agricultural production offers considerable benefits in improving overall operational management of agricultural production.

Integrating linkage and radiation hybrid mapping data for bovine chromosome 15.

BACKGROUND: Bovine chromosome (BTA) 15 contains a quantitative trait loci (QTL) for meat tenderness, as well as several breaks in synteny with human chromosome (HSA) 11. Both linkage and radiation hybrid (RH) maps of BTA 15 are available, but the linkage map lacks gene-specific markers needed to identify genes underlying the QTL, and the gene-rich RH map lacks associations with marker genotypes needed to define the QTL. Integrating the maps will provide information to further explore the QTL as well as refine the comparative map between BTA 15 and HSA 11. A recently developed approach to integrating linkage and RH maps uses both linkage and RH data to resolve a consensus marker order, rather than aligning independently constructed maps. Automated map construction procedures employing this maximum-likelihood approach were developed to integrate BTA RH and linkage data, and establish comparative positions of BTA 15 markers with HSA 11 homologs. RESULTS: The integrated BTA 15 map represents 145 markers; 42 shared by both data sets, 36 unique to the linkage data and 67 unique to RH data. Sequence alignment yielded comparative positions for 77 bovine markers with homologs on HSA 11. The map covers approximately 32% of HSA 11 sequence in five segments of conserved synteny, another 15% of HSA 11 is shared with BTA 29. Bovine and human order are consistent in portions of the syntenic segments, but some rearrangement is apparent. Comparative positions of gene markers near the meat tenderness QTL indicate the region includes separate segments of HSA 11. The two microsatellite markers flanking the QTL peak are between defined syntenic segments. CONCLUSIONS: Combining data to construct an integrated map not only consolidates information from different sources onto a single map, but information contributed from each data set increases the accuracy of the map. Comparison of bovine maps with well annotated human sequence can provide useful information about genes near mapped bovine markers, but bovine gene order may be different than human. Procedures to connect genetic and physical mapping data, build integrated maps for livestock species, and connect those maps to more fully annotated sequence can be automated, facilitating the maintenance of up-to-date maps, and providing a valuable tool to further explore genetic variation in livestock.

Lineage-specific imprinting and evolution of the zinc-finger gene ZIM2.

We have carried out an in-depth comparative analysis of a 100-kb genomic interval containing two imprinted genes, PEG3 and ZIM2, using sequences derived from human, mouse, and cow. In all three mammals, ZIM2 is located at a similar genomic distance and in the same orientation relative to PEG3, indicating the basic structural conservation of this imprinted locus. However, several lineage-specific changes have occurred that affect the exon structure and imprinting status of ZIM2. Human ZIM2 and PEG3 share a set of 5' exons and a common promoter, and both genes are paternally expressed. In contrast, mouse and cow Zim2 genes do not share 5' exons with Peg3, and Zim2 employs a separate downstream promoter in both species. The imprinting status of Zim2 is also not conserved among mammals; mouse Zim2 is expressed biallelically in testis but predominantly from the maternal allele in brain, while cow Zim2 is expressed biallelically in testis. The separate transcription of Zim2 and Peg3 and the change in promoter usage and imprinting status appear to have resulted from independent insertional events that have placed unrelated genes, Zim1 and Ast1, respectively, between Zim2 and Peg3 in mouse and cow. Our results suggest that PEG3 and ZIM2 represent the two original genes at this locus and that rearrangements have occurred independently in different mammalian lineages in recent evolutionary times. Our data also suggest that exon-sharing of human PEG3 and ZIM2 was not ancestral, but may represent a fusion event joining the two neighboring genes and bringing ZIM2 under paternal expression control. These observations are striking in light of the structural and functional conservation that typifies other imprinted domains and suggest that the PEG3/ZIM2 imprinted domain may have evolved in an unusual lineage-specific pattern.

Evolution of T1 black holes in patients with multiple sclerosis imaged monthly for 4 years.

T1 black holes (BHs) on MRIs may represent either areas of oedema or axonal loss in patients with multiple sclerosis. BHs begin as contrast enhancing lesions (CELs) and evolve differently from patient to patient, and within the same patient over time. We analysed BHs formation over a 4-year period. Forty-eight monthly MRIs of nine non-treated multiple sclerosis patients were evaluated for numbers of CELs and BHs. A BH was defined as a hypointense lesion on a T1 pre-contrast image that coincided with a region of high signal intensity on the T2-weighted images. A BH was considered as acute (ABH) when it occurred coincidently with the presence of enhancement and as persisting (PBH) when present after the cessation of enhancement. The present study aimed to analyse: (i) the incidence of CELs and new PBHs, and the accumulation of PBHs; (ii) the relationship between the quantity of the CELs in a given month and the likelihood of accumulating PBHs in the subsequent month; and (iii) the relationship between the duration of CELs and PBHs. Pitman's correlation test evaluated the effect of time on either the increase of CELs and new PBHs or the accumulation of PBHs, while a multiple logistic regression analysis evaluated the relationship between progression of time and CELs, and the increase of PBHs in a multivariate model. The relationship between the enhancing lesions duration and the PBHs duration, or the time to revert back to an isointense lesion was analysed using Kaplan-Meier survival models. PBHs accumulated (P < 0.001) in all patients, but the formation of new PBHs increased in four patients (P < or = 0.007) in conjunction with an increase in either the quantity of CELs (P < 0.001, for two patients) or the proportion of CELs turning into PBHs (P < or = 0.02, for two patients). Logistic regression analysis showed that neither progression of time nor the number of CELs in a given month were able to predict the probability of increasing the number of PBHs in the subsequent month in any patient. Out of 397 ABHs, 55.7% evolved to a PBH. The duration of PBHs correlated with the duration of enhancement. PBHs preceded by CELs observable on a single MRI persisted for a shorter time (P < 0.002) than those preceded by CELs visible on > or =2 monthly MRIs. The formation of a new PBH was found to be related to CELs activity; however, duration of PBHs is most likely a consequence of the duration of the enhancement.

Selection and use of SNP markers for animal identification and paternity analysis in U.S. beef cattle.

DNA marker technology represents a promising means for determining the genetic identity and kinship of an animal. Compared with other types of DNA markers, single nucleotide polymorphisms (SNPs) are attractive because they are abundant, genetically stable, and amenable to high-throughput automated analysis. In cattle, the challenge has been to identify a minimal set of SNPs with sufficient power for use in a variety of popular breeds and crossbred populations. This report describes a set of 32 highly informative SNP markers distributed among 18 autosomes and both sex chromosomes. Informativity of these SNPs in U.S. beef cattle populations was estimated from the distribution of allele and genotype frequencies in two panels: one consisting of 96 purebred sires representing 17 popular breeds, and another with 154 purebred American Angus from six herds in four Midwestern states. Based on frequency data from these panels, the estimated probability that two randomly selected, unrelated individuals will possess identical genotypes for all 32 loci was 2.0 x 10(-13) for multi-breed composite populations and 1.9 x 10(-10) for purebred Angus populations. The probability that a randomly chosen candidate sire will be excluded from paternity was estimated to be 99.9% and 99.4% for the same respective populations. The DNA immediately surrounding the 32 target SNPs was sequenced in the 96 sires of the multi-breed panel and found to contain an additional 183 polymorphic sites. Knowledge of these additional sites, together with the 32 target SNPs, allows the design of robust, accurate genotype assays on a variety of high-throughput SNP genotyping platforms.

Use of bovine EST data and human genomic sequences to map 100 gene-specific bovine markers.

A system to use bovine EST data in conjunction with human genomic sequence to improve the bovine linkage map over the entire genome or on specific chromosomes was evaluated. Bovine EST sequence was used to provide primer sequences corresponding to bovine genes, while human genomic sequence directed primer design to flank introns and produce amplicons of appropriate size for efficient direct sequencing. The sequence tagged sites (STS) produced in this way from the four sires of the MARC reference families were examined for single nucleotide polymorphisms (SNPs) that could be used to map the corresponding genes. With this approach, along with a primer/extension mass spectrometry SNP genotyping assay, 100 ESTs were placed on the bovine genetic linkage map. The first 70 were chosen at random from bovine EST-human genomic comparisons. An additional 30 ESTs were successfully mapped to bovine Chromosome 19 (BTA19), and comparison of the resulting BTA19 map to the position of the corresponding human orthologs on the HSA17 draft sequences revealed differences in the spacing and order of genes. Over 80% of successful amplicons contained SNPs, indicating that this is an efficient approach to generating EST-associated genetic markers. We have demonstrated the feasibility of constructing a linkage map based on SNPs associated with ESTs and the plausibility of utilizing EST, comparative mapping information, and human sequence data to target regions of the bovine genome for SNP marker development.