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Attention-deficit/hyperactivity disorder (ADHD) is a common childhood behavioral disorder most often characterized by inattentiveness, impulsivity, and hyperactivity. Current etiologic theories suggest that ADHD stems from abnormalities in dopaminergic and possibly noradrenergic brainstem nuclei that act to regulate a cortico-striato-thalamo-cortical network, believed to be critical for executive functions and the regulation of behavioral responses such as arousal, attention, and inhibition. Noninvasive structural and functional neuroimaging techniques provide a new avenue for exploring the validity of these theories. Despite their limitations, neuroimaging studies have provided a unique and otherwise inaccessible, biological perspective of ADHD. Collectively, the studies reviewed here reveal that dysfunction in arousal, behavioral inhibition, and attention associated with ADHD may result from structural abnormalities in frontostriatal regions that in turn result in diminished activity essential for normal function. MRDD Research Reviews 6:214–219, 2000. © 2000 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Abstract We used mitochondrial DNA sequences from three gene regions and two tRNAs (ND4, tRNA-HIS-SER, 12S, and 16S rDNA) to investigate the historical ecology of the New World pitviper clade Agkistrodon, with emphasis on the disjunct subspecies of the cantil, A. bilineatus. We found strong evidence that the copperhead (A. contortrix) is basal to its congeners, and that the cottonmouth (A. piscivorus) is basal to cantils. Phylogeography and natural history of the living terminal taxa imply that Agkistrodon primitively occupied relatively temperate habitats, with subsequent evolution of tropicality in ancestral A. bilineatus. Our best supported phylogeny rejects three gulf arc scenarios for the biogeography of A. bilineatus. We find significant statistical support for an initial divergence between populations on the east and west coasts of México and subsequent occupancy of the Yucatán Peninsula, by way of subhumid corridors in northern Central America. Based on phylogenetic relationships, morphological and molecular divergence, and allopatry we elevate A. b. taylori of northeastern México to species status. Taylor’s cantil is likely threatened by habitat destruction and small geographical range, and we offer recommendations for its conservation and management. [ABSTRACT FROM AUTHOR]

Lists articles published in volumes 1-12 of the 'Seminars in Dialysis.'

Abstract – The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200–250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The... [ABSTRACT FROM AUTHOR]

Approximately 10% of patients treated with erythropoiesis-stimulating agents ( ESAs) for the anemia of chronic kidney disease are unresponsive or relatively resistant to therapy. The etiology of this is usually linked to iron deficiency or an independent underlying illness. We describe a hemodialysis patient with a failed renal transplant 1.5 years earlier, who developed progressive erythropoietin resistance and anemia without an apparent cause. He simultaneously developed nonspecific malaise and fatigue. By exclusion, the only possible cause of these signs and symptoms was inflammation from acute and chronic rejection in the retained failed renal allograft. Following pulse steroids and transplant nephrectomy, the patient's symptoms resolved and both his hemoglobin improved and his erythropoietin requirements decreased significantly. The patient never required a blood transfusion and was successfully relisted for a deceased donor renal transplant. Hence, inflammation from a retained transplant allograft may be an under-recognized cause of erythropoietin resistance in dialysis patients. Although transplant nephrectomy remains a controversial practice due to concerns of alloantibody production, it may be considered in patients with failed renal allografts and anemia refractory to treatment with ESAs. [ABSTRACT FROM AUTHOR]

Discusses economic issues and future directions in managing iron deficiency anemia in chronic renal failure patients. Cost-benefit analysis of anemia management; Tests commonly used for monitoring iron status; Developments in intravenous iron and oral iron preparations; Reduction in adverse reactions to iron dextran.

Background: The etiological factors associated with the predisposition to develop alcohol dependence remain largely unknown. In recent years, neurophysiological anomalies have been identified in young and adult offspring of alcoholic probands. These neuroelectric features have been replicated in several laboratories across many different countries and are observed in male and female alcoholics and some of their relatives and offspring. Moreover, these electrophysiological abnormalities are heritable and predictive of future alcohol abuse or dependence. Methods: A model is presented which hypothesizes that the genetic predisposition to develop alcoholism involves an initial state of central nervous system (CNS) disinhibition/hyperexcitability. We propose that the event-related brain potential (ERP) anomalies reflect CNS disinhibition. This homeostatic imbalance results in excess levels of CNS excitability which are temporarily alleviated by the ingestion of alcohol. It is hypothesized that this hyperexcitability is heritable, and is critically involved in the predisposition toward alcoholism and the development of dependence. A brief review of the relevant literature is presented. Results: Neurophysiological, neurochemical, and genetic evidence support the proposed model. In addition, strikingly similar observations between animal research and the human condition are identified. Finally, it is asserted that the proposed model is primarily biological in nature, and therefore does not account for the entire clinical variance. Conclusion: A putative CNS homeostatic imbalance is noted as a critical state of hyperexcitability. This hyperexcitability represents a parsimonious model of what is inherited in the predisposition to develop alcoholism. It is our hope that this model will have heuristic value, resulting in the elucidation of etiological factors involved in alcohol dependence. [ABSTRACT FROM AUTHOR]

Dentin bonding has been the object of intensive research for many years. If a substance is expected to bond to a natural tooth surface, the morphologic and physiologic characteristics of the substrate determine both the bonding applications and testing methods used. This two-part article is a literature review. Part I is a detailed description of the structure of dentin. In Part II the importance of intrapulpal pressure on understanding bonding and testing will be discussed. [ABSTRACT FROM AUTHOR]

The effects of food intake on the P300 (P3) component of the event-related brain potential (ERP) were assessed In two studies. Experiment 1 compared 24 subjects who had not eaten within 6 hours of testing with 24 subjects who had consumed food within 3 hours of testing. P3 target stimulus amplitude was reduced significantly for the subjects who had not eaten relative to those who had eaten, whereas peak P3 latency was only moderately affected by the recency of food consumption over task conditions. In Experiment 2, P3 measurements, memory performance in a word recall task, and blood glucose levels were obtained from 24 subjects at three different times: 1) after a 14- hour fast, 2) 5 mm after consuming lunch, and 3) 30 min after consuming lunch. P3 target stimulus amplitude increased initially after food intake and decreased slightly at the third measurement time, while peak P3 latency became somewhat shorter immediately after food intake but then returned to baseline. Recall for recently presented items mimicked the P3 amplitude changes, whereas blood glucose levels increased monotonically across food conditions. The results from both studies suggest that: 1) target stimulus P3 amplitude is affected by the recency of food intake; 2) food-related P3 amplitude changes appear related to memory function; and 3) subjects should eat within several hours before ERPs are acquired to ensure that P3 component measurements reflect values indicative of normal bodily functioning. [ABSTRACT FROM AUTHOR]

Separating historical effects from recent anthropogenic pressures on population structure is paramount for understanding how species have persisted over time and how conservation efforts should best proceed. In this issue of Molecular Ecology, Chiucchi & Gibbs (2010) have separated the impacts of ancient and modern habitat fragmentation on genetic structure and migration rates in an endangered species of rattlesnake, the eastern massasauga ( Sistrurus catenatus). Previous studies have ignored ancient processes, estimated genetic isolation and migration using collections from different timescales, used markers with different rates of evolution or compared contemporary populations in both continuous and fragmented habitats (Keyghobadi 2007). Here, Chiucchi & Gibbs (2010) estimate migration parameters from microsatellites at two timescales using coalescent methods. Results strongly suggest that massasaugas are characterized by the low levels of migration with strong regional and range-wide differences, typical of many organisms residing in the patches of habitat surrounded by seas of agriculture, but that these patterns have existed since the Pleistocene. The novel methodology and hypotheses addressed in Chiucchi & Gibbs (2010) highlight future avenues for examining the impacts of fragmentation through time. [ABSTRACT FROM AUTHOR]

Drawing a direct connection between adaptive evolution at the phenotypic level and underlying genetic factors has long been a major goal of evolutionary biologists, but the genetic characterization of adaptive traits in natural populations is notoriously difficult. The study of evolution in experimental populations offers some help — initial conditions are known and changes can be tracked for extended periods under conditions more controlled than wild populations and more realistic than laboratory or greenhouse experiments. In this issue of Molecular Ecology, researchers studying experimental wheat populations over a 12-year period have demonstrated evolution in a major adaptive trait, flowering time, and parallel changes in underlying genetic variation ( Rhoné et al. 2008 ). Their work suggests that cis-regulatory mutations at a single gene may explain most of the flowering time variation in these populations. [ABSTRACT FROM AUTHOR]

Lists articles about dialysis clinics published in volumes 1-12 of 'Seminars in Dialysis.'

The article focuses on majority of congenital structural abnormalities including corpus callosum agenesis (CCA) are associated with genetic factors and stormorken syndrome (SS) is a rare autosomal dominant disorder characterized by miosis and thrombocytopenia. It mentions mutations in stromal interaction molecule which encodes a protein involved in calcium homeostasis. It also mentions whole-body magnetic resonance imaging demonstrated asplenia and muscle biopsy.

Speech signals provide both linguistic information (e.g., words and sentences) as well as information about the speaker who produced the message (i.e., social-indexical information). Listeners store highly detailed representations of these speech signals, which are simultaneously indexed with linguistic and social category membership. A variety of methodologies-forced-choice categorization, rating, and free classification-have shed light on listeners' cognitive-perceptual representations of the social-indexical information present in the speech signal. Specifically, listeners can accurately identify some talker characteristics, including native language status, approximate age, sex, and gender. Additionally, listeners have sensitivity to other speaker characteristics-such as sexual orientation, regional dialect, native language for non-native speakers, race, and ethnicity-but listeners tend to be less accurate or more variable at categorizing or rating speakers based on these constructs. However, studies have not necessarily incorporated more recent conceptions of these constructs (e.g., separating listeners' perceptions of race vs ethnicity) or speakers who do not fit squarely into specific categories (e.g., for sex perception, intersex individuals; for gender perception, genderqueer speakers; for race perception, multiracial speakers). Additional research on how the intersections of social-indexical categories influence speech perception is also needed. As the field moves forward, scholars from a variety of disciplines should be incorporated into investigations of how listeners' extract and represent facets of personal identity from speech. Further, the impact of these representations on our interactions with one another in contexts outside of the laboratory should continue to be explored. WIREs Cogn Sci 2017, 8:e1434. doi: 10.1002/wcs.1434 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Most biologists would agree that understanding the factors that influence gene flow among populations is important, because population connectivity is critical to effective conservation and management as well as to issues such as disease transmission and the degree of local adaptation. Nonetheless, our understanding of the mechanistic determinants of gene flow remains abysmally limited for many types of organisms. Predictably, some of the biggest gaps involve animals that are rare, secretive, and difficult to collect or handle — and thus, remain relatively unstudied for other traits as well. Large venomous snakes have long provided a classic example of such an under-studied group, but the situation has changed dramatically over recent years. The study by Clark et al. in this issue builds upon our increasingly sophisticated understanding of snake behaviour, to interpret patterns of gene flow in the light of our emerging knowledge of snake behavioural ecology. [ABSTRACT FROM AUTHOR]

Foreword 2 Recent trends in neurodisability: implications for research and prevention 4 Genetic contribution to neurodevelopmental disability: an overview 6 Normal and abnormal development of the central nervous system I 7 Normal and abnormal development of the central nervous system II 8 Neurodisability and the channelopathies 12 Neurodisability: metabolic and hormonal aspects 14 Studies of children in developing countries 18 Likely changes in obstetric practice – the next 10 years 25 The role of neuroimaging over the next 10 years 29 Cerebral palsy: can we prevent it? 30 Autism: known and unknown 31 Prevention of severe learning disability 35 Childhood epilepsy: secondary prevention is crucial 38 Specific learning disorders: primary and secondary prevention 42 [ABSTRACT FROM AUTHOR]

Studies the interplay between T helper type 1 and 2 cytokines and soluble major histocompatibility complex molecules during pregnancy. Role of the balance between the T helper types in immune response; T cell elimination during pregnancy; Mechanism for class 1 antigen release from different cells.

Lists case studies published in volumes 1-12 of the 'Seminars in Dialysis.'