Are routine chest radiographs still indicated after central line insertion? A scoping review.

Introduction: Central venous catheters are increasingly inserted using point-of-care ultrasound (POCUS) guidance. Following insertion, it is still common to request a confirmatory chest radiograph for subclavian and internal jugular lines, at least outside of the operating theater. This scoping review addresses: (i) the justification for routine post-insertion radiographs, (ii) whether it would better to use post-insertion POCUS instead, and (iii) the perceived barriers to change. Methods: We searched the electronic databases, Ovid MEDLINE (1946-) and Ovid EMBASE (1974-), using the MESH terms ("Echography" OR "Ultrasonography" OR "Ultrasound") AND "Central Venous Catheter" up until February 2023. We also searched clinical practice guidelines, and targeted literature, including cited and citing articles. We included adults (⩾18 years) and English and French language publications. We included randomized control trials, prospective and retrospective cohort studies, systematic reviews, and surveys. Results: Four thousand seventy-one articles were screened, 117 full-text articles accessed, and 41 retained. Thirteen examined cardiac/vascular methods; 5 examined isolated contrast-enhanced ultrasonography; 7 examined isolated rapid atrial swirl sign; and 13 examined combined/integrated methods. In addition, three systematic reviews/meta-analyses and one survey addressed barriers to POCUS adoption. Discussion: We believe that the literature supports retiring the routine post-central line chest radiograph. This is not only because POCUS has made line insertion safer, but because POCUS performs at least as well, and is associated with less radiation, lower cost, time savings, and greater accuracy. There has been less written about perceived barriers to change, but the literature shows that these concerns- which include upfront costs, time-to-train, medicolegal concerns and habit- can be challenged and hence overcome.

Brain connectivity in body dysmorphic disorder compared with controls: a diffusion tensor imaging study.

BACKGROUND: Several neuroimaging studies have investigated brain grey matter in people with body dysmorphic disorder (BDD), showing possible abnormalities in the limbic system, orbitofrontal cortex, caudate nuclei and temporal lobes. This study takes these findings forward by investigating white matter properties in BDD compared with controls using diffusion tensor imaging. It was hypothesized that the BDD sample would have widespread significantly reduced white matter connectivity as characterized by fractional anisotropy (FA). METHOD: A total of 20 participants with BDD and 20 healthy controls matched on age, gender and handedness underwent diffusion tensor imaging. FA, a measure of water diffusion within a voxel, was compared between groups on a voxel-by-voxel basis across the brain using tract-based spatial statistics within the FSL package. RESULTS: Results showed that, compared with healthy controls, BDD patients demonstrated significantly lower FA (p < 0.05) in most major white matter tracts throughout the brain, including in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Lower FA levels could be accounted for by increased radial diffusivity as characterized by eigenvalues 2 and 3. No area of higher FA was found in BDD. CONCLUSIONS: This study provided the first evidence of compromised white matter integrity within BDD patients. This suggests that there are inefficient connections between different brain areas, which may explain the cognitive and emotion regulation deficits within BDD patients.

Genomic loci associated with performance limiting equine overriding spinous processes (kissing spines).

Commonly known as "Kissing Spines" (KS), the pathological mechanisms underlying impingement and overriding of spinous processes (ORSPs) in horses are poorly understood. Thoroughbreds, Warmbloods, and stock-type breeds, including Paint Horses and Quarter Horses are at increased risk for developing clinical signs of KS. A total of 155 stock-type and Warmblood horses presented at collaborating veterinary clinics and hospitals were examined using a strict clinical and radiographical phenotyping scheme to grade each horse from 0 for unaffected controls to 4 for severe KS. Following genotyping with the Illumina Equine SNP70 array (Illumina, Inc.) a Genome Wide Association Study (GWAS) using 61,229 filtered individual Single Nucleotide Polymorphisms (SNPs) was performed to the KS grade phenotype. Two significantly associated SNPs (BIEC2-668062 and BIEC2-668013) on chromosome 25 defined a ~1.4 Gb candidate region containing approximately 17 coding genes (EquCab3) and 195 ENSEMBL annotated variants. Investigation of the best associated SNP (BIEC2-668062) on chr25 demonstrates a significant correlation with an increase in one KS grade, on average, per A allele in this population. A significant effect of breed group, age, height or sex was not observed in this population. These preliminary results demonstrate the potential for KS diagnosis and preventative measures for WB/ST individuals supported by increased genetic risk for more severe KS grade. We propose further research including other affected breeds and evaluating causative variants, as well as the effect of BIEC2-668062 in these populations.

Evaluation of dynamic testing for pituitary pars intermedia dysfunction diagnosis in donkeys.

BACKGROUND: Endocrine disorders are common in donkeys. Pituitary pars intermedia dysfunction (PPID) is thought to be a frequent disturbance in donkeys due to their longevity. However, information on PPID dynamic testing in donkeys is lacking. OBJECTIVES: The objective of this study was to evaluate the previously described guidelines for PPID diagnosis in horses in donkeys with suspicion of PPID. STUDY DESIGN: Prospective experimental study. METHODS: Eighty donkeys were evaluated for PPID suspicion based on clinical signs and baseline adrenocorticotropic hormone (ACTH) concentrations. Six mix-breed donkeys (one jack and five non-pregnant jennies) fulfilling inclusion criteria were subjected to dexamethasone suppression test (DST), thyrotropin-releasing hormone stimulation test (TRH) and combined DST-TRH challenge. Tests were interpreted according to guidelines for PPID diagnosis in horses. RESULTS: Donkeys fulfilling inclusion criteria were diagnosed with PPID by TRH stimulation test (six of six). Both DST (three of six) and DST-TRH (4/6) challenges failed to detect those animals and showed conflicting results. Similarly, cortisol basal concentrations were not consistent with PPID suspicion. MAIN LIMITATIONS: Characterisation of seasonal and geographical location effect on baseline ACTH concentrations and response to TRH is compelling in this species. Further studies with a larger number of donkeys are needed. CONCLUSIONS: This is the first study in donkeys to evaluate common dynamic tests used for PPID diagnosis in horses. Preliminary results agree with the guidelines for PPID diagnosis in horses and baseline ACTH measurement followed by TRH challenge are recommended tests for diagnosis of PPID in donkeys.

In vitro effects of hydrochloric and lactic acids on bioelectric properties of equine gastric squamous mucosa.

REASONS FOR PERFORMING STUDY: Volatile fatty acids, byproducts of carbohydrate fermentation by resident bacteria, have been implicated in causing nonglandular (NG) gastric ulcers. Lactic acid (LA), also produced by stomach bacteria, may cause gastric ulcers when exposed to the equine NG mucosa. OBJECTIVES: To investigate the in vitro effects of LA on equine NG mucosa bioelectric properties, sodium transport and tissue resistance. METHODS: Gastric tissues obtained from 13 mature horses were studied in Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured, and electrical resistance (R) and conductance (G) calculated for tissues after addition of HCl and LA (5, 10, 20 and 40 mmol/l) in normal Ringer's solution (NRS). RESULTS: Mucosa exposed to HCl or LA (5, 10 and 20 mmol/l) in NRS (pH 1.5 and to a lesser extent pH 4.0) had a significant decrease in Isc and PD. Mucosa exposed to a high concentration of LA (40 mmol/l) in NRS (LRS) at pH 1.5 showed an increased G, but this increase was not significant. Values returned to baseline after solutions were returned to pH 7.0. Histological changes were consistent with HCl-induced (pH <4.0) acid damage. CONCLUSIONS: HCl induced alteration in bioelectric properties of equine NG mucosa whereas addition of LRS did not, other than those changes seen with HCl alone.

Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles-Revised Consensus Statement.

This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.

Cytochrome b and photosynthetic sulfur bacteria.

Chromatophores isolated from the purple sulfur bacterium Chromatium and the green sulfur bacterium Chlorobium exhibit absorbance changes in the cytochrome alpha-band region consistent with the presence of a b-type cytochrome. Cytochrome content determined by reduced minus oxidized difference spectra and by heme photochemically active bacteriochlorophyll (reaction-center bacteriochlorophyll). The b-type cytochrome in Chromatium has an alpha-band maximum at 560 nm and a midpoint oxidation-reduction potential of -5 mV at pH 8.0. The b-type cytochrome in Chlorobium has an alpha-band maximum at 564 nm and an apparent midpoint oxidation-reduction potential near -90 mV. Chromatophores isolated from both Chromatium and Chlorobium cells catalyze a photoreduction of cytochrome b that is enhanced in the presence of antimycin A. Antimycin A and 2-n-heptyl-4-hydroxyquinoline-N-oxide inhibit endogenous (but not phenazine methosulfate-mediated) cyclic photophosphorylation in Chromatium chromatophores and non-cyclic electron flow from Na-2S to NADP in Chlorobium chromatophores. These observations suggest that b-type cytochromes may function in electron transport reactions in photosynthetic sulfur bacteria.

Hidden electrophoretic variation at the xanthine dehydrogenase locus in a natural population of Drosophila melanogaster.

Sixty-two isochromosomal lines of D. melanogaster were screened for cryptic electrophoretic variation at the xanthine dehydrogenase (XDH) locus. Sequential polyacrylamide vertical slab gel electrophoresis was performed using four electrophoretic criteria. A total of 15 classes of electromorphs were revealed. D. melanogaster appears to exhibit as much polymorphism at this locus as other extensively studied Drosophila species.--No evidence for loci on the X or second chromosomes which modified XDH mobility was found. Six of the electromorphs were mapped to the Xdh (ry) structural locus. Eight of the remaining nine classes exhibited mobility variation consistent with structural variation at the Xdh locus. The final class exhibited aberrant patterns and is under further study.

Elevated leg systolic pressures and arterial calcification in diabetic occlusive vascular disease.

Systolic occlusion leg and brachial pressures were determined using a Doppler ultrasonic method in 24 diabetic subjects with either past or evolving gangrene due to arterial occlusive disease of the lower extremities. The leg-brachial ratios were correlated with x-ray determined leg vascular calcification. Ratios above 1.10 were invariably associated with heavy continuous calcification of the tibial vessels; lesser degrees of arterial calcification had normal or depressed leg-brachial ratios. Medial calcification might be causally related to the abnormally elevated leg systolic pressures not infrequently noted in diabetic patients. Based on the observed occurrence of reamputation in association with normal or elevated leg-brachial ratios, it appears that a Doppler pressure index above 0.90 is not a reliable indicator of adequate blood flow in severe diabetic occlusive arterial disease.

Amino acid intake and urinary zinc excretion in newborn infants receiving total parenteral nutrition.

Zinc deficiency is well described in infants on total parenteral nutrition (TPN). Urinary Zn excretion is the major source of Zn loss in the parenterally fed infant; factors causing increased zincuria will predispose the infant to Zn deficiency and affect the recommended Zn intake dosage. Histidine, threonine, and lysine have been shown to bind Zn increasing its renal ultrafilterability. The effect of the infusion of high and low lysine (206 +/- 34 vs 158 +/- 38 mg.kg-1.d-1; means +/- SD), threonine (147 +/- 24 vs 113 +/- 27), and histidine (124 +/- 34 vs 85 +/- 15) on urinary Zn excretion were determined in 23 newborns on TPN who received similar Zn intakes (6.8 +/- 1.4 mumol.kg-1.d-1). After a 72-h adaptation period each infant had urine collected for two 24-h periods. Despite the significant difference in amino acid intakes, mean urinary Zn excretion was identical (1.58 +/- 0.73 vs 1.56 +/- 0.63 mumol.kg-1.d-1). Hyperzincuria, therefore, does not occur when amino acids are infused at rates appropriate for the safety and nutritional maintenance of neonates.

Modification of glycogen deposition by priming glucose loads: the second-meal phenomenon.

Glucose priming modifies tolerance and oxidation of subsequent loads. To assess effects in glycogenesis, rats were given a D-[U14C]-glucose load, either alone or preceded by one or two unlabeled hourly doses. The incorporation of 14C into total liver glycogen was 8.6 +/- 0.4% of the glucose dose and was little changed by priming loads. Total liver glycogen was 169 +/- 10 mg after one load and 276 +/- 12 mg after two; after three it fell to 243 +/- 20 mg. In muscle, net incorporation of 14C was 9.6 +/- 0.6% of the first but fell to 6.9 +/- 0.4% of the third glucose 14C dose/100 g. Muscle glycogen concentration rose at a decremental rate with priming. Net incorporation of glucose 14C into hepatic glycogen remains constant after repeated loads even after storage is reduced. In keeping with the reported peripheral resistance to glucose uptake in the second-meal phenomenon, repeated loading is associated with reduction of 14C-glucose incorporation into muscle glycogen.

Protein secondary structure prediction using two-level case-based reasoning.

We have developed a two-level case-based reasoning architecture for predicting protein secondary structure. The central idea is to break the problem into two levels: (i) reasoning at the object (protein) level and using the global information from this level to focus on a more restricted problem space; (ii) decomposing objects into pieces (segments) and reasoning at the level of internal structures. As a last step to the procedure, inferences from the parts of the internal structure are synthesized into predictions about global structure. The architecture has been developed and tested on a commonly used data set with 69.5% predictive accuracy. It was then tested on a new data set with 68.2% accuracy. With additional tuning, over 70% accuracy was achieved. In addition, a series of experiments were conducted to test various aspects of the method and the results are informative.

Carcinogenicity predictions for a group of 30 chemicals undergoing rodent cancer bioassays based on rules derived from subchronic organ toxicities.

Rodent carcinogenicities for a group of 30 chemicals which form the subject of the Second NIEHS Predictive-Toxicology Evaluation Experiment are predicted based on their subchronic organ toxicities. Predictions are made by rules learned by the rule learning (RL) induction program.

The ferredoxin/thioredoxin system: a key element in the regulatory function of light in photosynthesis.

In addition to its well-established function in supplying the energy for carbon dioxide assimilation, light plays a regulatory role in photosynthesis. The ferredoxin/thioredoxin system is a major mechanism whereby light functions in this capacity. Here, light absorbed by chlorophyll is converted via ferredoxin into a reductant messenger, reduced thioredoxin, that interacts with key target enzymes, thereby changing their catalytic activities. In this way, the green plant achieves maximum efficiency of its photosynthetic (light) and heterotrophic (dark) capabilities.

Potentiation of 14C-glucose oxidation by priming glucose loads: effect of starvation.

The mechanism of the Staub-Traugott effect or facilitated glucose disposal after successive glucose loads has remained elusive. In earlier publications, we have shown it can be independent of circulating hormone and free fatty acid levels. We have also proposed that it might partially depend on the rapid induction of glycolytic pathways, which are known to be depressed by prolonged fast. Mature rats were given 1.75 gm/kg glucose doses intravenously at 60-minute intervals. Respiratory CO2 was collected at 15-minute intervals over a 120-minute period following administration of the carrier glucose plus 6 microCi/100 gm rat weight of 14C-D-glucose, given either as the first, second, or third challenge. In rats fasted 14 hours there was potentiation of labeled CO2 recovered after each successive load. After three days of starvation, both relative 14C-glucose oxidation to 14CO2 as well as absolute 14CO2 increments after each load were lower. The changes in relative oxidation of an intravenous glucose load might partly account for the facilitated disposal of blood glucose seen in the second and third hours in overnight-fasted rats (Staub-Traugott effect). However, although rats fasted for three days had suppressed the Staub effect, the increments in oxidation were attenuated but still present, suggesting that alterations of other pathways must participate in the disappearance of this effect after fasting.

Pseudoephedrine and air travel-associated ear pain in children.

BACKGROUND: Young children often appear bothered by ear pain during ascent and descent while traveling on commercial airplanes. While pseudoephedrine hydrochloride is effective in decreasing the risk for earache in adults with recurrent air travel-associated ear pain, such use in children has not been studied. OBJECTIVE: To assess the efficacy and side effects of prophylactic pseudoephedrine in children traveling by air. DESIGN: A placebo-controlled, double-blind clinical trial. SUBJECTS AND METHODS: Children aged 6 months to 6 years were included in this study. Pseudoephedrine hydrochloride (1 mg/kg body weight) or placebo was administered 30 to 60 minutes prior to departure on commercial air flights. Caregivers noted historical details and the degree of apparent ear pain, drowsiness, and excitability with ascent and descent. RESULTS: Ninety-one flights involving 50 children were studied, with ear pain being reported in 13 (14%) of flights. Ear pain was not associated with a history of air travel-associated ear pain, recent ear infection, or recent upper airway symptoms. Pseudoephedrine use was not associated with a decrease in ear pain during either ascent (4% with pseudoephedrine vs 5% with placebo; P approximately 1.00) or descent (12% with pseudoephedrine vs. 13% with placebo; P approximately 1.00). Pseudoephedrine use was, however, linked to drowsiness at takeoff (60% with pseudoephedrine vs. 27% with placebo; P = .003) but not at landing (P = .39). Treatment was not associated with excitability at takeoff (P = .09) or landing (P approximately 1.00). CONCLUSIONS: Ear pain is not uncommon in children traveling by commercial aircraft. The predeparture use of pseudoephedrine does not decrease the risk for in-flight ear pain in children but is associated with drowsiness.

A temporal analysis of QMR.

OBJECTIVE: To understand better the trade-offs of not incorporating explicit time in Quick Medical Reference (QMR), a diagnostic system in the domain of general internal medicine, along the dimensions of expressive power and diagnostic accuracy. DESIGN: The study was conducted in two phases. Phase I was a descriptive analysis of the temporal abstractions incorporated in QMR's terms. Phase II was a pseudo-prospective controlled experiment, measuring the effect of history and physical examination temporal content on the diagnostic accuracy of QMR. MEASUREMENTS: For each QMR finding that would fit our operational definition of temporal finding, several parameters describing the temporal nature of the finding were assessed, the most important ones being: temporal primitives, time units, temporal uncertainty, processes, and patterns. The history, physical examination, and initial laboratory results of 105 consecutive patients admitted to the Pittsburgh University Presbyterian Hospital were analyzed for temporal content and factors that could potentially influence diagnostic accuracy (these included: rareness of primary diagnosis, case length, uncertainty, spatial/causal information, and multiple diseases). RESULTS: 776 findings were identified as temporal. The authors developed an ontology describing the terms utilized by QMR developers to express temporal knowledge. The authors classified the temporal abstractions found in QMR in 116 temporal types, 11 temporal templates, and a temporal hierarchy. The odds of QMR's making a correct diagnosis in high temporal complexity cases is 0.7 the odds when the temporal complexity is lower, but this result is not statistically significant (95% confidence interval = 0.27-1.83). CONCLUSIONS: QMR contains extensive implicit time modeling. These results support the conclusion that the abstracted encoding of time in the medical knowledge of QMR does not induce a diagnostic performance penalty.

Designing medical informatics research and library--resource projects to increase what is learned.

Careful study of medical informatics research and library-resource projects is necessary to increase the productivity of the research and development enterprise. Medical informatics research projects can present unique problems with respect to evaluation. It is not always possible to adapt directly the evaluation methods that are commonly employed in the natural and social sciences. Problems in evaluating medical informatics projects may be overcome by formulating system development work in terms of a testable hypothesis; subdividing complex projects into modules, each of which can be developed, tested and evaluated rigorously; and utilizing qualitative studies in situations where more definitive quantitative studies are impractical.

The potential of organ specific toxicity for predicting rodent carcinogenicity.

Relationships between organ specific toxicity (specifications of the presence or absence of 43 morphological effects in 32 organs) observed from 13-week subchronic studies and rodent carcinogenicity were investigated by manually measuring the concordance of each feature and also automatically using the RL (Rule Learner) induction program. Of the 32 organs, the presence or absence of any effect in liver or kidney was found very relevant to rodent carcinogenicity. While the concordance of Salmonella genotoxicity with rodent carcinogenicity was only 60%, the battery of liver and kidney was 74% accurate with 75% sensitivity and 71% specificity. Further, using the RL program, rule sets based on organ specific toxicity together with the default predictions based on Salmonella mutagenicity were on average 80% accurate with 83% sensitivity and 82% specificity.