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1.
Sci Rep ; 14(1): 7192, 2024 03 26.
Article in English | MEDLINE | ID: mdl-38531999

ABSTRACT

Among disabling post-traumatic stress symptoms (PTSS) are irritability, aggressive behavior, distressing memories and general impaired cognition and negative mood. Art therapy interventions, including mask-making, can potentially alleviate these symptoms. We tested the hypothesis that art conveys emotions and predicted that blinded viewers would be able to perceive changes in theoretically derived emotional profiles expressed in art made by military personnel with PTSS from the onset to the end of therapy. Five service members and veterans exhibiting PTSS were enrolled in an 8-session art therapy protocol, during which they artistically transformed papier-mâché masks at the beginning and end of the protocol. We found that blinded viewers without knowledge of the masks' creation stage (onset or end of therapy) read initial masks as conveying more negative emotions (e.g., angry, upset, and challenged) and later masks as conveying more positive emotions (calm and pleasure). Based on the assessments from the blinded evaluators, we infer the emotional transition experienced by the participants was expressed in the masks. In an exploratory arm of the study, we also found that viewers were better able to empathize with the negative emotions experienced by participants with PTSS when asked to explicitly take their perspective.


Subject(s)
Art Therapy , Military Personnel , Stress Disorders, Post-Traumatic , Veterans , Humans , Stress Disorders, Post-Traumatic/psychology , Irritable Mood
2.
Braz J Med Biol Res ; 54(6): e10317, 2021.
Article in English | MEDLINE | ID: mdl-33909855

ABSTRACT

Physical performance is a multifactorial and complex trait influenced by environmental and hereditary factors. Environmental factors alone have been insufficient to characterize all outstanding phenotypes. Recent advances in genomic technologies have enabled the investigation of whole nuclear and mitochondrial genome sequences, increasing our ability to understand interindividual variability in physical performance. Our objective was to evaluate the association of mitochondrial polymorphic loci with physical performance in Brazilian elite military personnel. Eighty-eight male military personnel who participated in the Command Actions Course of the Army were selected. Total DNA was obtained from blood samples and a complete mitochondrial genome (mtDNA) was sequenced using Illumina MiSeq platform. Twenty-nine subjects completed the training program (FINISHED, 'F'), and fifty-nine failed to complete (NOT_FINISHED, 'NF'). The mtDNA from NF was slightly more similar to genomes from African countries frequently related to endurance level. Twenty-two distinct mtDNA haplogroups were identified corroborating the intense genetic admixture of the Brazilian population, but their distribution was similar between the two groups (FST=0.0009). Of 745 polymorphisms detected in the mtDNA, the position G11914A within the NADPH gene component of the electron transport chain, was statistically different between F and NF groups (P=0.011; OR: 4.286; 95%CI: 1.198-16.719), with a higher frequency of the G allele in group F individuals). The high performance of military personnel may be mediated by performance-related genomic traits. Thus, mitochondrial genetic markers such as the ND4 gene may play an important role on physical performance variability.


Subject(s)
DNA, Mitochondrial , Military Personnel , Brazil , DNA, Mitochondrial/genetics , Haplotypes/genetics , Humans , Male , NADP , Physical Functional Performance
3.
Braz. j. med. biol. res ; 54(6): e10317, 2021. graf
Article in English | LILACS | ID: biblio-1249305

ABSTRACT

Physical performance is a multifactorial and complex trait influenced by environmental and hereditary factors. Environmental factors alone have been insufficient to characterize all outstanding phenotypes. Recent advances in genomic technologies have enabled the investigation of whole nuclear and mitochondrial genome sequences, increasing our ability to understand interindividual variability in physical performance. Our objective was to evaluate the association of mitochondrial polymorphic loci with physical performance in Brazilian elite military personnel. Eighty-eight male military personnel who participated in the Command Actions Course of the Army were selected. Total DNA was obtained from blood samples and a complete mitochondrial genome (mtDNA) was sequenced using Illumina MiSeq platform. Twenty-nine subjects completed the training program (FINISHED, 'F'), and fifty-nine failed to complete (NOT_FINISHED, 'NF'). The mtDNA from NF was slightly more similar to genomes from African countries frequently related to endurance level. Twenty-two distinct mtDNA haplogroups were identified corroborating the intense genetic admixture of the Brazilian population, but their distribution was similar between the two groups (FST=0.0009). Of 745 polymorphisms detected in the mtDNA, the position G11914A within the NADPH gene component of the electron transport chain, was statistically different between F and NF groups (P=0.011; OR: 4.286; 95%CI: 1.198-16.719), with a higher frequency of the G allele in group F individuals). The high performance of military personnel may be mediated by performance-related genomic traits. Thus, mitochondrial genetic markers such as the ND4 gene may play an important role on physical performance variability.


Subject(s)
Humans , Male , DNA, Mitochondrial/genetics , Military Personnel , Haplotypes/genetics , Brazil , Physical Functional Performance , NADP
4.
Forensic Sci Int Genet ; 34: 162-169, 2018 05.
Article in English | MEDLINE | ID: mdl-29486434

ABSTRACT

The STR sequence template file published in 2016 as part of the considerations from the DNA Commission of the International Society for Forensic Genetics on minimal STR sequence nomenclature requirements, has been comprehensively revised and audited using the latest GRCh38 genome assembly. The list of forensic STRs characterized was expanded by including supplementary autosomal, X- and Y-chromosome microsatellites in less common use for routine DNA profiling, but some likely to be adopted in future massively parallel sequencing (MPS) STR panels. We outline several aspects of sequence alignment and annotation that required care and attention to detail when comparing sequences to GRCh37 and GRCh38 assemblies, as well as the necessary matching of MPS-based allele descriptions to previously established repeat region structures described in initial sequencing studies of the less well known forensic STRs. The revised sequence guide is now available in a dynamically updated FTP format from the STRidER website with a date-stamped change log to allow users to explore their own MPS data with the most up-to-date forensic STR sequence information compiled in a simple guide.


Subject(s)
DNA Fingerprinting , Microsatellite Repeats , Software , Forensic Genetics/standards , High-Throughput Nucleotide Sequencing , Humans
5.
Forensic Sci Int Genet ; 23: 19-24, 2016 07.
Article in English | MEDLINE | ID: mdl-26974236

ABSTRACT

In the process of establishing short tandem repeat (STR) sequence variant nomenclature guidelines in anticipation of expanded forensic multiplexes for massively parallel sequencing (MPS), it was discovered that the STR D5S2500 has multiple positions and genomic characteristics reported. This ambiguity is because the marker named D5S2500 consists of two different microsatellites forming separate components in the capillary electrophoresis multiplexes of Qiagen's HDplex (Hilden, Germany) and AGCU ScienTech's non-CODIS STR 21plex (Wuxi, Jiangsu, China). This study outlines the genomic details used to identify each microsatellite and reveals the D5S2500 marker in HDplex has the correctly assigned STR name, while the D5S2500 marker in the AGCU 21plex, closely positioned a further 1643 nucleotides in the human reference sequence, is an unnamed microsatellite. The fact that the D5S2500 marker has existed as two distinct STR loci undetected for almost ten years, even with reported discordant genotypes for the standard control DNA, underlines the need for careful scrutiny of the genomic properties of forensic STRs, as they become adapted for sequence analysis with MPS systems. We make the recommendation that precise chromosome location data must be reported for any forensic marker under development but not in common use, so that the genomic characteristics of the locus are validated to the same level of accuracy as its allelic variation and forensic performance. To clearly differentiate each microsatellite, we propose the name D5S2800 be used to identify the Chromosome-5 STR in the AGCU 21plex.


Subject(s)
DNA Fingerprinting , Microsatellite Repeats , Electrophoresis, Capillary , Gene Frequency , Genetic Markers , Humans , Multiplex Polymerase Chain Reaction
6.
Neuroscience ; 310: 198-205, 2015 Dec 03.
Article in English | MEDLINE | ID: mdl-26386296

ABSTRACT

Contrast adaptation, generated by prolonged viewing of a high contrast spatial pattern, is known to reduce perceptual sensitivity to subsequently presented stimuli of similar spatial frequency (SF). Neural correlates of this pattern-specific contrast adaptation have been described in several classic studies in cat primary visual cortex (V1). These results have also recently been extended to mice, which is a genetically manipulable animal model. Here we attempt to parse the potential mechanisms contributing to this phenomenon by determining whether the SF specificity of contrast adaptation observed in mouse V1 neurons depends on the spike rate elicited by the adapting gratings. We found that adapting stimuli that drove a neuron more strongly generally produced more adaptation, implicating an intrinsic or fatigue-like process. Importantly, we also observed that slightly stronger contrast adaptation was produced when the adapting SF matched the test SF even when matched and nonmatched adapting gratings elicited similar spike rates indicating extrinsic or network processes contribute as well.


Subject(s)
Action Potentials/physiology , Contrast Sensitivity/physiology , Neurons/physiology , Visual Cortex/cytology , Visual Cortex/physiology , Adaptation, Physiological , Animals , Male , Mice , Mice, Inbred C57BL , Photic Stimulation , Reaction Time/physiology
7.
Public Health ; 129(5): 545-8, 2015 May.
Article in English | MEDLINE | ID: mdl-25769348

ABSTRACT

OBJECTIVES: Assess differences in perceived health status among individuals receiving colonoscopy screening based on smoking status. STUDY DESIGN: Cross-sectional data were collected as part of a larger study investigating whether verbal and non-verbal communication and behaviors of gastroenterologists and nurses. METHOD: Data for this study were collected between 2011 and 2013 among receiving colonoscopy screenings. Data were collected as part of a study assessing patients (n = 1785) undergoing colonoscopy screenings about their expectations, concerns, understanding of the procedure, and perceived health status. Differences between current, former and never smokers were analyzed using a one-way between subjects ANOVA, with a Scheffe post hoc. RESULTS: Post hoc analyses revealed that current smokers were significantly different from former or never smokers on the following variables: days their physical health was not good, days their mental health was not good, days health influenced their activities, days pain influenced their ability to perform activities, perceived general health, and current anxiety. CONCLUSION: This study looked at perceived health among individuals receiving colonoscopy screening by on smoking status, a relevant population based on the recent Surgeon Generals link. Former smokers reported similar health status across all variables as never smokers, suggesting the effect of quitting smoking on self-perceived health. With this link, tailored smoking cessation messages to smokers receiving colonoscopy screenings may be an excellent vantage point for a smoking cessation intervention.


Subject(s)
Colonoscopy , Diagnostic Self Evaluation , Mass Screening , Smoking/psychology , Adult , Aged , Colorectal Neoplasms/prevention & control , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Smoking/epidemiology , Smoking Cessation
8.
Med Phys ; 28(8): 1597-609, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11548929

ABSTRACT

We propose a principled formulation of the ROC curve that is constrained in a realistic way by the mechanism of probability summation. The constrained and conventional ROC formulations were fitted to 150 separate sets of rating data taken from previous observer studies of 250 or 529 chest radiographs. A total of 20 different readers had used either discrete or continuous rating scales to evaluate those chest cases for likelihood of separate specified abnormalities: interstitial disease, pulmonary nodule, pneumothorax, alveolar infiltrate, or rib fracture. Both ROC formulations were fitted separately to every set of rating data using maximum-likelihood statistical procedures that specified each ROC curve by normally distributed latent variables with two scaling parameters, and estimated the area below the ROC curve (Az) with its standard error. The conventional and constrained binormal formulations usually fitted ROC curves that were nearly indistinguishable in form and in Az. But when fitted to asymmetric rating data that contained few false-positive cases, the conventional ROC curves often rose steeply, then flattened and extrapolated into an unrealistic upward "hook" at the higher false-positive rates. For those sets of rating data, the constrained ROC curves (without hooks) estimated larger values for Az with smaller standard errors. The constrained ROC formulation describes observers' ratings of cases at least as well as the conventional ROC, and always guarantees a realistic fitted curve for observer performance. Its estimated parameters are easy to interpret, and may also be used to predict observer accuracy in localizing the image abnormalities.


Subject(s)
Models, Statistical , Probability , ROC Curve , Radiography, Thoracic/methods , Databases as Topic , False Positive Reactions , Humans , Observer Variation
9.
Arch Pediatr Adolesc Med ; 155(9): 1038-42, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11529806

ABSTRACT

OBJECTIVE: To assess the effect of reported corticosteroid exposure on neonatal levels of 17-hydroxyprogesterone (17-OHP), the cortisol precursor used in newborn screening for congenital adrenal hyperplasia, in newborns weighing less than 2500 g at birth. DESIGN: A retrospective study of newborns weighing less than 2500 g at birth and exposed to corticosteroids as reported on their newborn screening card compared with newborns weighing less than 2500 g at birth and reported as not exposed to corticosteroids. METHODS: Birth weight, gestational age, age at screening, special care information, and name of screening hospital were obtained from newborn screening cards for 16 115 newborns screened in Michigan during the first 3 months of 2000. Levels of 17-OHP, measured by fluoroimmunoassay, were obtained from Michigan's Newborn Screening Program database. RESULTS: The mean 17-OHP level for the 69 low-birth-weight newborns in the corticosteroid-exposed group was 52 ng/mL, which was higher than that for the 771 low-birth-weight newborns in the unexposed group (35 ng/mL) (P<.001). Reported corticosteroid use did not decrease the number of expected borderline positive screening results for congenital adrenal hyperplasia (P>.05). Levels of 17-OHP varied by birth weight in corticosteroid-exposed and unexposed newborns. CONCLUSIONS: Corticosteroid exposure may not suppress screening 17-OHP levels. Therefore, newborn screening should not be delayed in premature newborns because of antenatal exposure to corticosteroids.


Subject(s)
17-alpha-Hydroxyprogesterone/blood , Adrenal Cortex Hormones/administration & dosage , Adrenal Hyperplasia, Congenital/diagnosis , Neonatal Screening , Adrenal Hyperplasia, Congenital/blood , Female , Gestational Age , Humans , Infant, Low Birth Weight , Infant, Newborn , Male , Michigan , Predictive Value of Tests , Pregnancy , Retrospective Studies
10.
Physiol Behav ; 72(4): 549-58, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11282139

ABSTRACT

Estrogen treatment can suppress the intake of a previously presented gustatory conditioned stimulus (CS). This finding has been interpreted as an estrogen-induced conditioned taste aversion. However, a distinction must be made between taste aversion and taste avoidance. In particular, tastes are only considered aversive if they elicit a stereotypic behavioral response, otherwise the reduction in intake is classified as an avoidance. Although aversive orofacial responses have been reported in male rats after taste-estrogen pairings, they have not been examined in ovariectomized female rats. The goal of the present investigation, then, was to use similar procedures to determine whether conditioned aversion also mediates the estrogen-induced reduction of intake in female rats. Animals were introduced to a novel 0.1% saccharin solution and immediately thereafter were given a subcutaneous injection of vehicle or estradiol benzoate (10 microg). Responses were assessed using a two-bottle preference test, a one-bottle acceptance test, and a taste reactivity (TR) test. The results confirmed previous reports of a reduced preference for saccharin after saccharin-estradiol pairing using the two-bottle test. The reduction in intake during the one-bottle test, however, was not accompanied by stereotypic aversive responses, such as gaping. Surprisingly, a similar reduction in intake also occurred when using a backward conditioning procedure in which estrogen was injected before, rather than after, CS access. Thus, the present results show that the suppressive effects of estrogen reflect an avoidance, rather than aversion and, moreover, that the reduced intake may be due to an unconditioned, rather than a conditioned, response.


Subject(s)
Eating/drug effects , Estrogens/pharmacology , Taste/drug effects , Animals , Avoidance Learning/drug effects , Body Weight/drug effects , Depression, Chemical , Estradiol/pharmacology , Female , Ovariectomy , Rats , Rats, Sprague-Dawley , Sexual Behavior, Animal/drug effects
11.
Prenat Diagn ; 21(13): 1111-3, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11787033

ABSTRACT

A case of prenatally diagnosed non-mosaic trisomy 20 in cells cultured from a chorionic villus sample (CVS)is presented. The term placental karyotype was also non-mosaic trisomy 20. The karyotype of the newborn was 46,XY/47,XY,+20 in foreskin cultures and in a second skin culture; blood lymphocyte culture was 46,XY. Aside from diffuse, hypopigmentary swirls along the lines of Blaschko observed on his extremities and trunk, referred to as hypomelanosis of Ito, the patient is clinically normal at 8 3/4 years of age. In addition, he is one of the oldest reported cases of mosaic trisomy 20 confirmed after birth for which the clinical outcome has been monitored. This case demonstrates that these trisomy 20 findings are compatible with normal psychomotor development and phenotype.


Subject(s)
Chorionic Villi Sampling , Chromosomes, Human, Pair 20 , Trisomy , Adult , Cells, Cultured , Female , Follow-Up Studies , Gestational Age , Humans , Infant, Newborn , Karyotyping , Male , Maternal Age , Mosaicism , Pigmentation Disorders/genetics , Pregnancy , Pregnancy, High-Risk
12.
Med Phys ; 27(8): 1920-33, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10984238

ABSTRACT

Six radiologists used continuous scales to rate 529 chest-film cases for likelihood of five different types of abnormalities (interstitial disease, nodule, pneumothorax, alveolar infiltrate, and rib fracture) in each of six replicated readings, yielding 36 separate ratings of each case for the five abnormalities. Separate data analyses of all cases and subsets of the difficult/subtle cases for each abnormality estimated the relative gains in accuracy (linear-scaled area below the ROC curve) obtained by averaging the case-ratings across (a) six independent replications by each reader (25% gain), (b) six different readers within each replication (34% gain), or (c) all 36 readings (48% gain). Although accuracy differed among both readers and abnormalities, ROC curves for the median ratings showed similar relative gains in accuracy, somewhat greater than those predicted from the measured rating correlations. A model for variance components in the observer's latent decision variable could predict these gains from measured correlations in the single ratings of cases. Depending on whether the model's estimates were based on realized accuracy gains or on rating correlations, about 48% or 39% of each reader's total decision variance (summed variance for positive and negative cases) consisted of random (within-reader) error that was uncorrelated between replications, another 10% or 14% came from idiosyncratic responses to individual cases, and about 43% or 47% was systematic variation that all readers found in the sampled cases.


Subject(s)
Observer Variation , Radiography, Thoracic/methods , Humans , Models, Statistical , Multivariate Analysis , ROC Curve , Radiology/standards , Reproducibility of Results
13.
Neuroendocrinology ; 69(5): 339-51, 1999 May.
Article in English | MEDLINE | ID: mdl-10343175

ABSTRACT

Mineralocorticoids, such as deoxycorticosterone acetate (DOCA), and angiotensin II (AngII) act synergistically in the brain to elicit salt appetite. Glucocorticoids, such as dexamethasone (DEX), also may enhance the behavioral effects of DOCA and AngII. However, the brain regions involved in these behavioral interactions have not been elucidated. This study tested the hypothesis that DEX potentiates the effects of DOCA on AngII binding, especially at the AT1 receptor. We confirmed that DEX potentiated the effects of DOCA on salt appetite. Concomitantly, steroid-specific and region-specific changes in AT1 binding were noted. Specifically, in the hypothalamic paraventricular nucleus, treatment with DEX or DOCA + DEX increased AT1 binding. In the subfornical organ (SFO) and area postrema, there was an increase in AT1 binding when both steroids were combined, but not when given individually. However, there was no change in AT2 binding in any brain region studied and no change in AT1 or AT2 binding to either receptor subtype in the pituitary. The results indicate that DOCA and DEX may increase the sensitivity of the brain to the behavioral and physiological actions of AngII by upregulating AT1 receptors in the SFO and area postrema.


Subject(s)
Angiotensin II/metabolism , Brain Chemistry/drug effects , Feeding Behavior/drug effects , Glucocorticoids/pharmacology , Mineralocorticoids/pharmacology , Receptors, Angiotensin/metabolism , Sodium, Dietary , Animals , Autoradiography , Body Weight/drug effects , Brain Stem/drug effects , Brain Stem/metabolism , Male , Organ Size/drug effects , Pituitary Gland/drug effects , Pituitary Gland/metabolism , Prosencephalon/drug effects , Prosencephalon/metabolism , Rats , Rats, Sprague-Dawley , Receptor, Angiotensin, Type 1 , Receptor, Angiotensin, Type 2 , Receptors, Angiotensin/biosynthesis , Receptors, Angiotensin/drug effects
14.
AJR Am J Roentgenol ; 172(5): 1185-8, 1999 May.
Article in English | MEDLINE | ID: mdl-10227486

ABSTRACT

OBJECTIVE: The objective of this study was to assess the effectiveness of film management in a large urban teaching hospital. SUBJECTS AND METHODS: For 5 days in March 1998, individuals seeking access to imaging studies performed in the radiology department of a large urban hospital were questioned about their activities and were physically followed in an effort to characterize the efficiency and effectiveness of the department in servicing individuals not employed by the department. Activities in the department were recorded, and the times to visit completion and the failure rates were assessed. RESULTS: Of the 381 visitors to the department who were followed, 321 were hospital employees and 186 were physicians. The average total time spent in the department was 4 min, during which 2 min were spent viewing images or obtaining consultation. Physicians were in the department an average of only 7 min with 3 min for consultation and image viewing. During the 381 visits, we monitored 753 separate transactions, 693 of which were completed successfully. We found no instances in which a physician indicated that a patient's treatment would be delayed or altered because of film mismanagement and only one instance in which it was suggested that a study may have to be repeated. CONCLUSION: This study found a high level of efficiency and effectiveness in file room operations.


Subject(s)
Medical Records Systems, Computerized , Radiology Department, Hospital/organization & administration , Radiology Information Systems , Filing , Hospital Bed Capacity, 500 and over , Hospitals, Teaching , Hospitals, Urban , Humans , Pennsylvania , Radiology Department, Hospital/statistics & numerical data
15.
Int J Med Inform ; 54(2): 115-26, 1999 May.
Article in English | MEDLINE | ID: mdl-10219951

ABSTRACT

This study investigates a simple Bayesian belief network for the diagnosis of breast cancer, and specifically addresses the question of whether integrating image and non-image based features into a single network can yield better performance than hybrid combinations of independent networks. From a dataset of 419 cases, including 92 malignancies, 13 features relating to mammographic findings, physical examinations and patients' clinical histories, were extracted to build three Bayesian belief networks. The scenarios tested included a network incorporating all features and two hybrids which combined the outputs of sub-networks corresponding to the image or non-image features. Average areas (Az) under the corresponding ROC curves were used as measures of performance. The network incorporating only image based features performed better (Az =0.81) than that using nonimage features (Az = 0.71). Both hybrid classifiers yielded better performance (Az =0.85 for averaging and Az = 0.87 for logistic regression), but neither hybrid was as accurate as the network incorporating all features (Az = 0.89). This preliminary study suggests that, like human observers who concurrently consider different types of information, a single classifier that simultaneously evaluates both image and non-image information can achieve better diagnostic performance than the hybrid combinations considered here.


Subject(s)
Bayes Theorem , Breast Neoplasms/diagnosis , Diagnosis, Computer-Assisted , Adult , Artificial Intelligence , Breast Neoplasms/pathology , Diagnosis, Differential , Diagnostic Imaging , Female , Humans , Reproducibility of Results , Sensitivity and Specificity
16.
Acad Radiol ; 6(12): 723-9, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10887893

ABSTRACT

RATIONALE AND OBJECTIVES: The authors attempted to assess experimentally the magnitude of reader variability and the correlations and interactions among cases, readers, and modalities during observer performance studies and their possible effects on study design and sample size. MATERIALS AND METHODS: Published data from 32 selected receiver operating characteristic (ROC) studies were reviewed to compare the magnitude of the variance component from readers with the variance component from modality. Estimates of correlation and interactions among cases, readers, and modalities were also computed directly from ROC data ascertained during two large studies performed in our laboratory. Each of these two studies included 529 cases and six readers, but one study used eight modalities and the other nine. RESULTS: Published results indicate that reader variability is task dependent and larger (P < .05) than modality variability in detection of interstitial disease. Measured correlations between modalities for the same reader were task dependent and ranged from 0.35 to 0.59. Modality-by-reader and modality-by-case interactions often are not important factors. The random error term was greater than the modality-by-reader interaction in 11 of 20 comparisons and greater than the modality-by-case interaction in eight of 20 comparisons. CONCLUSION: Use of the same cases interpreted with different modes is justifiable in many situations because of the high variability from readers. This comprehensive review of existing ROC studies resulted in parameter assessments that can be used to better estimate sample-size requirements in multireader ROC studies.


Subject(s)
Observer Variation , ROC Curve , Radiography, Thoracic , Humans , Research Design
17.
Mol Phylogenet Evol ; 10(1): 23-36, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9751915

ABSTRACT

Lineages which exhibit little morphological change over geologic time are evolutionarily and ecologically interesting, but often taxonomically difficult. For some morphologically conservative groups, not only is it almost impossible to identify significant changes in fossil forms over time, but the relationships among extant populations are often poorly understood due to lack of known characters which clearly delimit species. Notostracan crustaceans are a classic example of such "living fossils." The paradoxical characteristics of long-term stasis in gross morphology and hypervariability of many individual morphological characters make notostracans an especially taxonomically challenging group. We used molecular and biochemical techniques to investigate the taxonomic and phylogenetic relationships of four nominal species within the genus Lepidurus in North America, three of which had been alternately abandoned, resurrected, or synonymized under a single, globally distributed morphospecies since their original descriptions in the 1800s. Data from a 330-bp sequence of the mitochondrial 12S rDNA gene and from nine allozyme loci consistently indicate five highly genetically divergent clades among the populations we used to represent the four nominal species. Diagnostic molecular characters, magnitudes of genetic divergence among clades, and the fact that these genetically distinct clades have broadly overlapping geographical ranges strongly suggest that the five clades are reproductively isolated species. One of the nominal species (L. couesii) is not monophyletic, but rather consists of two species which are not sister taxa. The other three nominal species (L. lemmoni, L. packardi, and L. bilobatus) are supported as valid phylogenetic species. The best current hypothesis for phylogenetic relationships among the five species is provided by a simultaneous analysis of both 12S rDNA and allozyme data, which places L. bilobatus and L. "couesii"-1 as sister taxa and L. "couesii"-2 as the most basal of all the Lepidurus species included in this study. These results point to the existence of cryptic species within the current classification scheme for Lepidurus, the need for further taxonomic work within the Notostraca in general, and the role that genetic techniques can play in clarifying the systematics of morphologically conservative groups.


Subject(s)
Crustacea/classification , Phylogeny , Animals , DNA/genetics , DNA/isolation & purification , Genetic Variation , Isoenzymes/genetics , North America , Polymerase Chain Reaction , Sequence Analysis, DNA
19.
Obes Res ; 6(1): 69-75, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9526973

ABSTRACT

Lactate, an important metabolic substrate for peripheral tissues and the liver, is released in significant amounts from adipose tissue. Using a perifusion system, we measured lactate production from glucose and response to insulin in isolated mesenteric and epididymal adipocytes removed from fed or fasted male Wistar rats at two stages of growth and development: (a) lean rats (7 weeks to 9 weeks old, weighing approximately 250 g), and (b) fatter rats (6 months to 8 months old, weighing approximately 550 g). The results show that lactate production in perifused adipocytes is regulated by the prior nutritional state of the animals, by the adipose tissue region, and by the presence of insulin in the perifusate. In fat cells from lean rats, basal lactate production was significantly higher (p<0.05) in mesenteric cells when compared with epididymal cells, both in the fed state (7.8 nmo/10(7) fat cells per minute vs. 2.9 nmol/10(7) fat cells per minute) and after 2 days of fasting (13.6 nmol vs. 3.5 nmol). When the response to 1 mU/mL insulin was studied, however, the relative increase in lactate production produced by insulin was greater in the epididymal cells than in the mesenteric cells, in both the fed (194% vs. 91% over basal, respectively) and fasted (360% vs. 55% over basal, p<0.05) state. When larger epididymal adipocytes from fatter rats were compared with an equal number of smaller epididymal cells from leaner rats, the larger cells produced 4.99 nmol of lactate/10(7) fat cells per minute, whereas the smaller cells produced 2.93 nmol (p=0.08). Large fat cells showed a small and nonsignificant response to insulin in either type of cell (epididymal vs. mesenteric) or nutritional state (fed vs. fasted). This study indicates that distinct regional differences exist in lactate production and response to insulin. Mesenteric adipose tissue, which drains directly into the portal vein and provides substrates to the liver, may be an important source of lactate for the hepatic processes of gluconeogenesis and glycogenesis.


Subject(s)
Adipocytes/drug effects , Adipocytes/metabolism , Glucose/metabolism , Insulin/pharmacology , Lactic Acid/biosynthesis , Obesity/metabolism , Aging , Animals , Body Weight , Cell Size , Epididymis/metabolism , Fasting , Male , Mesoderm/metabolism , Perfusion , Rats , Rats, Wistar
20.
Acad Radiol ; 5(3): 173-80, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9522883

ABSTRACT

RATIONALE AND OBJECTIVES: The authors compare a 43-micron computed radiographic system with a mammographic screen-film system for detection of simulated microcalcifications in an observer-performance study. MATERIALS AND METHODS: The task of detecting microcalcifications was simulated by imaging aluminum wire segments (200-500 microns in length; 100, 125, or 150 microns in diameter) that overlapped with tissue background structures produced by beef brisket. A total of 288 such simulations were generated and examined with both computed radiography and conventional screen-film mammography techniques. Computed radiography was performed with high-resolution plates, a 43-micron image reader, and a 43-micron laser film printer. Computed radiographic images were printed with simple contrast enhancement and compared with screen-film images in a receiver operating characteristic study in which experienced readers detected and scored the simulated microcalcifications. Observer performance was quantitated and compared by computing the area under the receiver operating characteristic curve. RESULTS: Although the resolution of the computed radiography system was better than that of commercial systems, it fell short of that of screen-film systems. For the 100-micron microcalcifications, the difference in the average area under the curve was not statistically significant, but it was significant for the larger simulated microcalcifications: the average area under the curve was 0.58 for computed radiography versus 0.76 for screen-film imaging for the 125-micron microcalcifications and 0.83 versus 1.00, respectively, for the 150-micron microcalcifications. CONCLUSION: Observer performance in the detection of small simulated microcalcifications (100-150 microns in diameter) is better with screen-film images than with high-resolution computed radiographic images.


Subject(s)
Breast Diseases/diagnostic imaging , Calcinosis/diagnostic imaging , Mammography , Phantoms, Imaging , Radiographic Image Enhancement , X-Ray Intensifying Screens , Female , Humans , ROC Curve
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