Does veno-arterial carbon dioxide gradient provide an adequate estimation of cardiac index in pulmonary hypertension?

AIMS: Pulmonary hypertension (PH) management is dependent on cardiac output (CO) assessment. The gold standard Fick method for CO and cardiac index (CI) measurement is not widely available. An accessible and reliable method for CO/CI estimation is needed not only in catheterization labs but also in other environments such as the intensive care unit, where pulmonary artery catheters are less likely to be used. We hypothesized that veno-arterial carbon dioxide gradient (PvaCO2) is a reliable surrogate for Fick CI in patients with PH. METHODS AND RESULTS: A single-centre retrospective analysis of patients with PH who underwent direct Fick CI (DFCI) measurement during right heart catheterization. The primary outcome was correlation between PvaCO2 and DFCI. To assess the agreement between central and mixed venous CO2 values, a separate prospective cohort of patients was analysed. Data from 186 patients with all haemodynamic types of PH were analysed. PvaCO2 moderately correlated with Fick CI, R = -0.51 [95% confidence interval (CI): -0.61, -0.39]. A higher PvaCO2 was associated with an increased risk of CI < 2.5 L/min/m2 (odds ratio: 1.88, 95% CI: 1.55, 2.35). Low thermodilution CI with normal veno-arterial carbon dioxide gradient values was associated with a thermodilution underestimation of Fick CI. In the prospective analysis of 32 patients, central venous CO2 overestimated mixed venous values (mean difference 3.3, 95% CI: 2.5, 4.0) and there was poor agreement overall (limits of agreement -1.10, 7.59). CONCLUSION: Veno-arterial carbon dioxide gradient moderately correlates with Fick CI and may be useful to identify patients with low CI. Central and mixed venous CO2 values should not be used interchangeably in PH.

Implementation of a Maternal Child Knowledgebase.

To advance the application of clinical data to address maternal health we developed and implemented a Maternal Child Knowledgebase (MCK). The MCK integrates data from every pregnancy that received care at the University of Iowa Hospitals & Clinics (UIHC) and links information from the pregnancy episode to the delivery episode and between the mother and child. This knowledgebase contains integrated information regarding diagnoses, medications, mother and child vitals, hospital admissions, depression screenings, laboratory value results, and procedure information. It also collates information from the electronic health record (EPIC), the Social Security Death Index, and the Medication Administration Record into one knowledgebase. To enhance usability, we designed a custom viewer with several pre-designed queries and reports that eliminates the need for users to be proficient in SQL coding. The recent implementation of the MCK has supported multiple projects and reduced the number of Obstetrics-related data queries to the Biomedical Informatics group.

Cardiovascular Manifestations, Imaging, and Outcomes in Systemic Lupus Erythematosus: An Eight-Year Single Center Experience in the United States.

Systemic lupus erythematosus (SLE) is a challenging autoimmune and multi-system condition. With advances in cardiovascular screening and therapies for SLE patients, we evaluated the cardiovascular characteristics, multi-modality imaging, and outcomes of SLE at our tertiary referral center over an 8 year period. Consecutive patients from our SLE registry from April 2012 to March 2020 were retrospectively analyzed. Data pertaining to cardiovascular manifestations, investigations, management, and outcomes were assessed. We studied 258 SLE patients (mean age 42.2 ± 14.7 years); 233 (90.3%) were female. The main cardiac manifestations at index SLE clinic were pericardial disease in 33.3%, valve disease in 18%, cardiomyopathy in 9.6%, and stroke in 7.4%. During a mean follow-up of 3.0 ± 2.2 years after index SLE clinic, there were 5 (1.9%) deaths, 24 (9.3%) cardiovascular events, and 44 (17.1%) SLE-related hospitalizations. A history of stroke and hypertension were independently associated with cardiovascular events, hazard ratio (HR) (95% confidence intervals (CI)) of 5.38 (1.41-20.6) and 3.31 (1.02-10.7), respectively, while younger age and lower albumin predicted SLE-related hospitalizations. Cardiovascular manifestations are prevalent in SLE, especially for pericardial, valvular, and atherosclerotic diseases. With contemporary SLE and cardiovascular management, subsequent adverse cardiovascular events were infrequent in this study.

Using the Internet for image transfer in a regional trauma network: effect on CT repeat rate, cost, and radiation exposure.

PURPOSE: The aims of this study were to evaluate an Internet-based and compact disc-based image transfer system and to compare this system with others in the literature, specifically regarding effects on repeat imaging rate, cost, and radiation dose to patients transferred to a level I regional trauma center. METHODS: Five hundred consecutive trauma patients transferred to a level I trauma center between June 1 and July 15, 2009, were included in the study. Images were transferred from an outside facility to the trauma center using the Internet and compact discs and uploaded to the trauma center's PACS. Radiographic studies and CT scans at the trauma center were classified as outside studies, completion studies, or repeat studies. Repeat rate, costs, and radiation doses of transferred and repeated CT scans were calculated. RESULTS: Four hundred ninety-one patients met the inclusion criteria. The patients' average age was 40.5 years, and 70% were men. The average Injury Severity Score was 14.7. Three hundred eighty-three patients had 852 CT studies and 380 nonextremity radiographs imported into the trauma center's PACS. At the trauma center, 494 completion CT scans and 2,924 radiographic studies were performed on these patients. Sixty-nine repeat CT scans were performed on 55 patients, equalling a 17% repeat rate. The total value of imported CT studies was $244,373.69. Repeat imaging totaled $20,495.95, or $84.65 per patient with transferred CT studies. CONCLUSIONS: Using a combination of the Internet and compact discs to transfer images during inter-hospital transfer is associated with much lower repeat rates than those in the literature, suggesting that regional PACS networks may be useful for reducing cost and radiation exposure associated with trauma.

Memory for the locations of environmental sounds.

The accuracy with which a single source of sound can be localized has been examined in many studies, but very few studies have examined the ability of participants to determine the absolute locations of multiple sources of sound. The current study assessed participants' abilities to determine and remember the locations of up to six sources of environmental sound that were positioned at a range of azimuths and elevations in virtual auditory space. In experiment 1, a sequence of one to six sounds was presented one, three, or five times in each trial and the target sound was nominated following presentation of the last sequence. In experiment 2, memory load was held constant by nominating the target sound prior to a single sequence presentation. Localization accuracy was observed to decrease as the number of sounds was increased to three or more under the conditions of experiment 1, but not those of experiment 2. In experiment 1, localization was more accurate when sequences were presented more than once. Pronounced primacy and recency effects were observed for the six sound conditions in experiment 1. An analysis of errors for those conditions indicated that immediate temporal errors, but not immediate spatial errors, were over-represented.

Progressive mucosal injury in patients with gastroesophageal reflux disease and increasing peripheral blood eosinophil counts.

HYPOTHESIS: Peripheral blood eosinophil count increases with the degree of mucosal injury associated with gastroesophageal reflux disease (GERD). DESIGN: Retrospective review. SETTING: Single-institution tertiary hospital. PATIENTS: Two hundred ninety-five patients (215 men and 80 women; median age, 57 years [interquartile range (IQR), 46-66 years]). One hundred had GERD without intestinal metaplasia, 100 had GERD with intestinal metaplasia, 40 had GERD with dysplasia, and 55 had GERD with intramucosal carcinoma. Results of complete blood count with differential and serum chemistry studies were compared among the groups using a nonparametric test for trend. RESULTS: Patients with a higher degree of mucosal injury were older (P < .001). There were no differences between white blood count, percent neutrophil count, absolute neutrophil count, and hematocrit levels among the groups. Serum albumin level decreased as the degree of mucosal injury increased (P = .04) but lost significance when controlled for age (P = .53). Percent eosinophil counts were 2.0 (IQR, 1.3-2.8) in patients with GERD without intestinal metaplasia, 2.5 (IQR, 1.6-3.7) in GERD with intestinal metaplasia, 2.6 (IQR, 1.7-4.4) in GERD with dysplasia, and 2.7 (IQR, 1.5-4.3) in GERD with intramucosal carcinoma. This progressive increase in the percent eosinophil count was statistically significant (P = .006), remained significant after controlling for age (P = .04), and was also significant when measuring the absolute eosinophil count. CONCLUSION: There is a progressive increase in the percent and absolute peripheral blood eosinophil count associated with progressive mucosal injury in patients with GERD.

Human gamma-satellite DNA maintains open chromatin structure and protects a transgene from epigenetic silencing.

The role of repetitive DNA sequences in pericentromeric regions with respect to kinetochore/heterochromatin structure and function is poorly understood. Here, we use a mouse erythroleukemia cell (MEL) system for studying how repetitive DNA assumes or is assembled into different chromatin structures. We show that human gamma-satellite DNA arrays allow a transcriptionally permissive chromatin conformation in an adjacent transgene and efficiently protect it from epigenetic silencing. These arrays contain CTCF and Ikaros binding sites. In MEL cells, this gamma-satellite DNA activity depends on binding of Ikaros proteins involved in differentiation along the hematopoietic pathway. Given our discovery of gamma-satellite DNA in pericentromeric regions of most human chromosomes and a dynamic chromatin state of gamma-satellite arrays in their natural location, we suggest that gamma-satellite DNA represents a unique region of the functional centromere with a possible role in preventing heterochromatin spreading beyond the pericentromeric region.

Cloning and characterization of zebrafish CTCF: Developmental expression patterns, regulation of the promoter region, and evolutionary aspects of gene organization.

CTCF is a nuclear phosphoprotein capable of using different subsets of its 11 Zn fingers (ZF) for sequence-specific binding to many dissimilar DNA CTCF-target sites. Such sites were identified in the genomic DNA of various multicellular organisms, in which the CTCF gene was cloned, including insects, birds, rodents, and primates. CTCF/DNA-complexes formed in vivo with different 50-bp-long sequences mediate diverse functions such as positive and negative regulation of promoters, and organization of all known enhancer-blocking elements ("chromatin insulators") including constitutive and epigenetically regulated elements. Abnormal functions of certain CTCF sites are implicated in cancer and in epigenetic syndromes such as BWS and skewed X-inactivation. We describe here the cloning and characterization of the CTCF cDNA and promoter region from zebrafish, a valuable vertebrate model organism. The full-length zebrafish CTCF cDNA clone is 4244 bp in length with an open reading frame (ORF) of 2391 bp that encodes 797 amino acids. The zebrafish CTCF amino acid sequence shows high identity (up to 98% in the zinc finger region) with human CTCF, and perfect conservation of exon-intron organization. Southern blot analyses indicated that the zebrafish genome contains a single copy of the CTCF gene. In situ hybridization revealed the presence of zebrafish CTCF transcripts in all early stages of embryogenesis. Transfection assays with luciferase reporter-constructs identified a core promoter region within 146 bp immediately upstream of the transcriptional start site of zebrafish CTCF that is located at a highly conserved YY1/Initiator element.

Conditional expression of the CTCF-paralogous transcriptional factor BORIS in normal cells results in demethylation and derepression of MAGE-A1 and reactivation of other cancer-testis genes.

Brother of the Regulator of Imprinted Sites (BORIS) is a mammalian CTCF paralog with the same central 11Zn fingers (11ZF) that mediate specific interactions with varying approximately 50-bp target sites. Regulated in vivo occupancy of such sites may yield structurally and functionally distinct CTCF/DNA complexes involved in various aspects of gene regulation, including epigenetic control of gene imprinting and X chromosome inactivation. The latter functions are mediated by meCpG-sensitive 11ZF binding. Because CTCF is normally present in all somatic cells, whereas BORIS is active only in CTCF- and 5-methylcytosine-deficient adult male germ cells, switching DNA occupancy from CTCF to BORIS was suggested to regulate site specificity and timing of epigenetic reprogramming. In addition to 11ZF-binding paternal imprinting control regions, cancer-testis gene promoters also undergo remethylation during CTCF/BORIS switching in germ cells. Only promoters of cancer testis genes are normally silenced in all somatic cells but activated during spermatogenesis when demethylated in BORIS-positive germ cells and are found aberrantly derepressed in various tumors. We show here that BORIS is also expressed in multiple cancers and is thus itself a cancer-testis gene and that conditional expression of BORIS in normal fibroblasts activates cancer-testis genes selectively. We tested if replacement of CTCF by BORIS on regulatory DNA occurs in vivo on activation of a prototype cancer-testis gene, MAGE-A1. Transition from a hypermethylated/silenced to a hypomethylated/activated status induced in normal cells by 5-aza-2'-deoxycytidine (5-azadC) was mimicked by conditional input of BORIS and is associated with complete switching from CTCF to BORIS occupancy at a single 11ZF target. This site manifested a novel type of CTCF/BORIS 11ZF binding insensitive to CpG methylation. Whereas 5-azadC induction of BORIS takes only few hours, derepression of MAGE-A1 occurred 1 to 2 days later, suggesting that BORIS mediates cancer-testis gene activation by 5-azadC. Indeed, infection of normal fibroblasts with anti-BORIS short hairpin RNA retroviruses before treatment with 5-azadC blocked reactivation of MAGE-A1. We suggest that BORIS is likely tethering epigenetic machinery to a novel class of CTCF/BORIS 11ZF target sequences that mediate induction of cancer-testis genes.

Reciprocal binding of CTCF and BORIS to the NY-ESO-1 promoter coincides with derepression of this cancer-testis gene in lung cancer cells.

Regulatory sequences recognized by the unique pair of paralogous factors, CTCF and BORIS, have been implicated in epigenetic regulation of imprinting and X chromosome inactivation. Lung cancers exhibit genome-wide demethylation associated with derepression of a specific class of genes encoding cancer-testis (CT) antigens such as NY-ESO-1. CT genes are normally expressed in BORIS-positive male germ cells deficient in CTCF and meCpG contents, but are strictly silenced in somatic cells. The present study was undertaken to ascertain if aberrant activation of BORIS contributes to derepression of NY-ESO-1 during pulmonary carcinogenesis. Preliminary experiments indicated that NY-ESO-1 expression coincided with derepression of BORIS in cultured lung cancer cells. Quantitative reverse transcription-PCR analysis revealed robust, coincident induction of BORIS and NY-ESO-1 expression in lung cancer cells, but not normal human bronchial epithelial cells following 5-aza-2'-deoxycytidine (5-azadC), Depsipeptide FK228 (DP), or sequential 5-azadC/DP exposure under clinically relevant conditions. Bisulfite sequencing, methylation-specific PCR, and chromatin immunoprecipitation (ChIP) experiments showed that induction of BORIS coincided with direct modulation of chromatin structure within a CpG island in the 5'-flanking noncoding region of this gene. Cotransfection experiments using promoter-reporter constructs confirmed that BORIS modulates NY-ESO-1 expression in lung cancer cells. Gel shift and ChIP experiments revealed a novel CTCF/BORIS-binding site in the NY-ESO-1 promoter, which unlike such sites in the H19-imprinting control region and X chromosome, is insensitive to CpG methylation in vitro. In vivo occupancy of this site by CTCF was associated with silencing of the NY-ESO-1 promoter, whereas switching from CTCF to BORIS occupancy coincided with derepression of NY-ESO-1. Collectively, these data indicate that reciprocal binding of CTCF and BORIS to the NY-ESO-1 promoter mediates epigenetic regulation of this CT gene in lung cancer cells, and suggest that induction of BORIS may be a novel strategy to augment immunogenicity of pulmonary carcinomas.

Chromatin architecture near a potential 3' end of the igh locus involves modular regulation of histone modifications during B-Cell development and in vivo occupancy at CTCF sites.

The murine Igh locus has a 3' regulatory region (3' RR) containing four enhancers (hs3A, hs1,2, hs3B, and hs4) at DNase I-hypersensitive sites. The 3' RR exerts long-range effects on class switch recombination (CSR) to several isotypes through its control of germ line transcription. By measuring levels of acetylated histones H3 and H4 and of dimethylated H3 (K4) with chromatin immunoprecipitation assays, we found that early in B-cell development, chromatin encompassing the enhancers of the 3' RR began to attain stepwise modifications typical of an open conformation. The hs4 enhancer was associated with active chromatin initially in pro- and pre-B cells and then together with hs3A, hs1,2, and hs3B in B and plasma cells. Histone modifications were similar in resting splenic B cells and in splenic B cells induced by lipopolysaccharide to undergo CSR. From the pro-B-cell stage onward, the approximately 11-kb region immediately downstream of hs4 displayed H3 and H4 modifications indicative of open chromatin. This region contained newly identified DNase I-hypersensitive sites and several CTCF target sites, some of which were occupied in vivo in a developmentally regulated manner. The open chromatin environment of the extended 3' RR in mature B cells was flanked by regions associated with dimethylated K9 of histone H3. Together, these data suggest that 3' RR elements are located within a specific chromatin subdomain that contains CTCF binding sites and developmentally regulated modules.

Familial cases of point mutations in the XIST promoter reveal a correlation between CTCF binding and pre-emptive choices of X chromosome inactivation.

The choice mechanisms that determine the future inactive X chromosome in somatic cells of female mammals involve the regulated expression of the XIST gene. A familial C(-43)G mutation in the XIST promoter results in skewing of X chromosome inactivation (XCI) towards the inactive X chromosome of heterozygous females, whereas a C(-43)A mutation found primarily in the active X chromosome results in the opposite skewing pattern. Both mutations point to the existence of a factor that might be responsible for the skewed patterns. Here we identify this factor as CTCF, a conserved protein with a 11 Zn-finger (ZF) domain that can mediate multiple sequence-specificity and interactions between DNA-bound CTCF molecules. We show that mouse and human Xist/XIST promoters contain one homologous CTCF-binding sequence with the matching dG-contacts, which in the human XIST include the -43 position within the DNase I footprint of CTCF. While the C(-43)A mutation abrogates CTCF binding, the C(-43)G mutation results in a dramatic increase in CTCF-binding efficiency by altering ZF-usage mode required for recognition of the altered dG-contacts of the mutant site. Thus, the skewing effect of the two -43C mutations correlates with their effects on CTCF binding. Finally, CTCF interacts with the XIST/Xist promoter only in female human and mouse cells. The interpretation that this reflected a preferential interaction with the promoter of the active Xist allele was confirmed in mouse fetal placenta. These observations are in keeping with the possibility that the choice of X chromosome inactivation reflects stabilization of a higher order chromatin conformation impinging on the CTCF-XIST promoter complex.

Spatio-temporal selectivity of loss of colour and luminance contrast sensitivity with multiple sclerosis and optic neuritis.

Colour and luminance-contrast thresholds were measured in the presence of dynamic Random Luminance-contrast Masking (RLM) in individuals who had had past diagnoses of optic neuritis (ON) some of whom have progressed to a diagnosis of multiple sclerosis (MS). To explore the spatio-temporal selectivity of chromatic and luminance losses in MS/ON, thresholds were measured using three different sizes and modulation rates of the RLM displays: small checks modulating slowly, medium-sized checks with moderate modulation and large checks modulating rapidly. The colour of the chromatic stimuli used were specified in a cone-excitation space to measure relative impairments in red-green and blue-yellow chromatic channels. These observers showed chromatic thresholds along the L/(L+M) axis that were higher than those along the S-cone axis for all display sizes/modulation rates and both red-green and blue-yellow colour thresholds were higher than luminance-contrast thresholds. The principal change in thresholds with spatio-temporal changes in the display was a reduction in thresholds for L/(L+M) and S-cones with increasing check size and modulation rate. However, luminance contrast thresholds did not change with display size/rate. These results are consistent with MS/ON selectively affecting processing in colour pathways rather than in the magnocellular pathway, and that within the colour pathways neurones with opposed L- and M-cone inputs are more damaged than colour-opponent neurons with input from S-cones.

Chromatic and luminance losses with multiple sclerosis and optic neuritis measured using dynamic random luminance contrast noise.

We measured thresholds for detecting changes in colour and in luminance contrast in observers with multiple sclerosis (MS) and/or optic neuritis (ON) to determine whether reduced sensitivity occurs principally in red-green or blue-yellow second-stage chromatic channels or in an achromatic channel. Colour thresholds for the observers with MS/ON were higher in the red-green direction than in the blue-yellow direction, indicating greater levels of red-green loss than blue-yellow loss. Achromatic thresholds were raised less than either red-green or blue-yellow thresholds, showing less luminance-contrast loss than chromatic loss. With the MS/ON observers, blue-yellow and red-green thresholds were positively correlated but increasing impairment was associated with more rapid changes in red-green thresholds than blue-yellow thresholds. These findings indicate that demyelinating disease selectively reduces sensitivity to colour vision over luminance vision and red-green colours over blue-yellow colours.

Isolation and characterization of oligotrophic acido-tolerant methanogenic consortia from a Sphagnum peat bog.

Two dense and highly enriched (up to 10(9) cells ml(-1), <10% of bacterial satellites) acido-tolerant (pH 4.0-6.5) methanogenic consortia, '26' and 'K', were isolated from the peat beneath a Sphagnum-Eriophorum-Carex community in West Siberia. Both consortia produced methane from CO2:H2 on chemically defined, diluted N-free media containing Ti(III)citrate as reducing agent. The phylogenetic analysis of 16S ribosomal DNA revealed three archaeal and nine bacterial sequence types. Consortium '26' contained single archaea Methanobacterium sp., represented by rods of 1.5-10x0.5-1.0 microm. In consortium 'K', there were two archaeal phylotypes, the respective methanogens were further differentiated morphologically with the fluorescence in situ hybridization technique: one less abundant (<2%) population of the long-curved rods (50-100x0.3-0.4 microm) fell into the order of Methanomicrobiales, while the dominant organism ( approximately 98%), represented by straight rods with abrupt rectangular ends (3-9x0.5 microm), was affiliated with earlier uncultured 'Rice cluster I'. The main bacterial satellite used citrate as a single carbon and energy source; it was similar in both consortia, and after isolation in pure culture, it was identified as a new member of the alpha-subclass of Proteobacteria. The other bacterial satellites were distributed among four taxonomic groups: the delta-subclass of Proteobacteria, the Flavobacterium-Bacteroides-Cytophaga line of descent, the Acidobacterium-Fibrobacter line of descent and the Green non-sulfur bacteria line of descent. At least 11 out of 12 components of acido-tolerant consortia are new to science at the species, genus and order levels; their existence until now was evident only from environmental gene retrievals. The Sphagnum wetlands, attracting attention only recently because of their global environmental role, are shown to be an especially valuable source of novel prokaryotic organisms.

Biomechanical analysis of cervical orthoses in flexion and extension: a comparison of cervical collars and cervical thoracic orthoses.

The analysis of current cervical collars (Aspen and Miami J collars) and cervical thoracic orthoses (CTOs) (Aspen 2-post and Aspen 4-post CTOs) in reducing cervical intervertebral and gross range of motion in flexion and extension was performed using 20 normal volunteer subjects. The gross sagittal motion of the head was measured relative to the horizon with the use of an optoelectronic motion measurement system. Simultaneous measurement of cervical intervertebral motion was performed with the use of a video fluoroscopy (VF) machine. Intervertebral motion was described as (1) the angular motion of each vertebra and (2) the translational motion of the vertebral centroid. We used surface electromyographic (EMG) signal data to compare subject efforts between the two collars and between the two CTOs. Each orthosis significantly reduced gross and intervertebral motion in flexion and extension (p < 0.05). No statistically significant differences were found between the Miami J and Aspen collars in reducing gross or intervertebral sagittal motion, except at C5-6. Both CTOs provided significantly more restriction of gross and intervertebral flexion and extension motion as compared to the two collars (p < 0.05). The Aspen 2-post CTO and 4-post CTO performed similarly in flexion, but the Aspen 4-post CTO provided significantly more restriction of extension motion (p < 0.05).