Prior differences in previous trauma exposure primarily drive the observed racial/ethnic differences in posttrauma depression and anxiety following a recent trauma

BACKGROUND

Racial and ethnic groups in the USA differ in the prevalence of posttraumatic stress disorder (PTSD). Recent research however has not observed consistent racial/ethnic differences in posttraumatic stress in the early aftermath of trauma, suggesting that such differences in chronic PTSD rates may be related to differences in recovery over time.

METHODS

As part of the multisite, longitudinal AURORA study, we investigated racial/ethnic differences in PTSD and related outcomes within 3 months after trauma. Participants (n = 930) were recruited from emergency departments across the USA and provided periodic (2 weeks, 8 weeks, and 3 months after trauma) self-report assessments of PTSD, depression, dissociation, anxiety, and resilience. Linear models were completed to investigate racial/ethnic differences in posttraumatic dysfunction with subsequent follow-up models assessing potential effects of prior life stressors.

RESULTS

Racial/ethnic groups did not differ in symptoms over time; however, Black participants showed reduced posttraumatic depression and anxiety symptoms overall compared to Hispanic participants and White participants. Racial/ethnic differences were not attenuated after accounting for differences in sociodemographic factors. However, racial/ethnic differences in depression and anxiety were no longer significant after accounting for greater prior trauma exposure and childhood emotional abuse in White participants.

CONCLUSIONS

The present findings suggest prior differences in previous trauma exposure partially mediate the observed racial/ethnic differences in posttraumatic depression and anxiety symptoms following a recent trauma. Our findings further demonstrate that racial/ethnic groups show similar rates of symptom recovery over time. Future work utilizing longer time-scale data is needed to elucidate potential racial/ethnic differences in long-term symptom trajectories.

Substance use patterns in 9-10 year olds: Baseline findings from the adolescent brain cognitive development (ABCD) study

BACKGROUND

The Adolescent Brain Cognitive Development ™ Study (ABCD Study®) is an open-science, multi-site, prospective, longitudinal study following over 11,800 9- and 10-year-old youth into early adulthood. The ABCD Study aims to prospectively examine the impact of substance use (SU) on neurocognitive and health outcomes. Although SU initiation typically occurs during teen years, relatively little is known about patterns of SU in children younger than 12.

METHODS

This study aims to report the detailed ABCD Study® SU patterns at baseline (n = 11,875) in order to inform the greater scientific community about cohort's early SU. Along with a detailed description of SU, we ran mixed effects regression models to examine the association between early caffeine and alcohol sipping with demographic factors, externalizing symptoms and parental history of alcohol and substance use disorders (AUD/SUD).

PRIMARY RESULTS

At baseline, the majority of youth had used caffeine (67.6 %) and 22.5 % reported sipping alcohol (22.5 %). There was little to no reported use of other drug categories (0.2 % full alcohol drink, 0.7 % used nicotine, <0.1 % used any other drug of abuse). Analyses revealed that total caffeine use and early alcohol sipping were associated with demographic variables (p's<.05), externalizing symptoms (caffeine p = 0002; sipping p = .0003), and parental history of AUD (sipping p = .03).

CONCLUSIONS

ABCD Study participants aged 9-10 years old reported caffeine use and alcohol sipping experimentation, but very rare other SU. Variables linked with early childhood alcohol sipping and caffeine use should be examined as contributing factors in future longitudinal analyses examining escalating trajectories of SU in the ABCD Study cohort.

Baseline brain function in the preadolescents of the ABCD Study

The Adolescent Brain Cognitive Development (ABCD) Study® is a 10-year longitudinal study of children recruited at ages 9 and 10. A battery of neuroimaging tasks are administered biennially to track neurodevelopment and identify individual differences in brain function. This study reports activation patterns from functional MRI (fMRI) tasks completed at baseline, which were designed to measure cognitive impulse control with a stop signal task (SST; N = 5,547), reward anticipation and receipt with a monetary incentive delay (MID) task (N = 6,657) and working memory and emotion reactivity with an emotional N-back (EN-back) task (N = 6,009). Further, we report the spatial reproducibility of activation patterns by assessing between-group vertex/voxelwise correlations of blood oxygen level-dependent (BOLD) activation. Analyses reveal robust brain activations that are consistent with the published literature, vary across fMRI tasks/contrasts and slightly correlate with individual behavioral performance on the tasks. These results establish the preadolescent brain function baseline, guide interpretation of cross-sectional analyses and will enable the investigation of longitudinal changes during adolescent development.

Sentinel lymph node biopsy procedure in squamous vulvar cancer. 10 years follow-up analysis

AIM

Application of sentinel lymph node biopsy (SLNB) procedure in early-stage vulvar cancer and analysis of results, recurrences and complications.

MATERIAL AND METHODS

40 patients with vulvar cancer and SLNB between 2008 and 2018 were retrospectively reviewed. During the surgical procedure the inguinofemoral lymph nodes were checked with a gamma probe to identify the sentinel nodes that were removed and referred for intraoperative pathological assessment. Subsequently, long-term patient follow-up was performed with analysis of complications, relapse and mortality.

RESULTS

40 patients (mean age: 72 years [47-86], the overall detection rate per patient was 95% and a total of 129 Sentinel Lymph Nodes (SLNs) were removed (3.22 SLN/patient). In 3 out of 25 patients with lateral tumour lesions drainage was bilateral and in 2 out of 15 with midline lesions drainage was unilateral. On lymphoscintigraphy, 16 out of 40 had bilateral drainage and 24 unilateral. A total of 119 SLN- and 10 SLN+ were obtained, in 8 out of 10 an inguinofemoral lymphadenectomy was performed. In the SLN- group, one case of lymphatic blockage and one false negative were included. In 12 out of 40 patients there were post-surgical complications, 4 of them lymphoedemas. In the median follow-up (40 months), 6 out of 10 with SLN+ (40% mortality) and 7 out of 30 SLN- (16% mortality) had recurrences.

CONCLUSIONS

SLNB in vulvar cancer is the technique of choice for correct staging and locoregional therapy. Correct clinical lymph node staging is important before surgery in order to avoid potential blockage drainages which could induce a false negative SLN.

Germination sensitivity to water stress in four shrubby species across the Mediterranean Basin

Mediterranean shrublands are generally water-limited and fire-driven ecosystems. Seed-based post-fire regeneration may be affected by varying rainfall patterns, depending on species sensitivity to germinate under water stress. In our study, we considered the germination response to water stress in four species from several sites across the Mediterranean Basin. Seeds of species with a hard coat (Cistus monspeliensis, C. salviifolius, Cistaceae, Calicotome villosa, Fabaceae) or soft coat (Erica arborea, Ericaceae), which were exposed or not to a heat shock and smoke (fire cues), were made to germinate under water stress. Final germination percentage, germination speed and viability of seeds were recorded. Germination was modelled using hydrotime analysis and correlated to the water balance characteristics of seed provenance. Water stress was found to decrease final germination in the three hard-seeded species, as well as reduce germination speed. Moreover, an interaction between fire cues and water stress was found, whereby fire cues increased sensitivity to water stress. Seed viability after germination under water stress also declined in two hard-seeded species. Conversely, E. arborea showed little sensitivity to water stress, independent of fire cues. Germination responses varied among populations of all species, and hydrotime parameters were not correlated to site water balance, except in E. arborea when not exposed to fire cues. In conclusion, the species studied differed in germination sensitivity to water stress; furthermore, fire cues increased this sensitivity in the three hard-seeded species, but not in E. arborea. Moreover, populations within species consistently differed among themselves, but these differences could only be related to the provenance locality in E. arborea in seeds not exposed to fire cues.

Disruptive behavior disorders and indicators of disinhibition in adolescents: The BRIEF-SR, anti-saccade task, and D-KEFS color-word interference test

Disinhibition contributes to the development of disruptive behavior disorders (DBD) in adolescents. Self-reports and behavioral tasks are commonly used to assess disinhibition, each with their unique strengths and limitations. Accordingly, it is important to identify which measure, or combination thereof, is the most effective in predicting DBD symptoms. This study assessed the relationship between DBD (symptoms of ADHD/ODD/CD) and two behavioral disinhibition tasks: the anti-saccade task and the D-KEFS color-word interference test, as well as a self-report measure (the BRIEF-SR). The results indicated that the BRIEF-Inhibit scale accounted for the majority of the variance in the DBD sum score. The anti-saccade task and color-word interference test were also significantly associated with an increase in the number of DBD symptoms endorsed. These behavioral tasks accounted for 9% additional variance than the self-report alone. Therefore, combining self-report measures with behavioral disinhibition tasks may provide the most thorough assessment of adolescent DBD.

Impact of a cleaner-burning cookstove intervention on blood pressure in Nicaraguan women

Few studies have evaluated the cardiovascular-related effects of indoor biomass burning or the role of characteristics such as age and obesity status, in this relationship. We examined the impact of a cleaner-burning cookstove intervention on blood pressure among Nicaraguan women using an open fire at baseline; we also evaluated heterogeneity of the impact by subgroups of the population. We evaluated changes in systolic and diastolic blood pressure from baseline to post-intervention (range: 273-383 days) among 74 female cooks. We measured indoor fine particulate matter (PM(2.5); N = 25), indoor carbon monoxide (CO; N = 32), and personal CO (N = 30) concentrations. Large mean reductions in pollutant concentrations were observed for all pollutants; for example, indoor PM(2.5) was reduced 77% following the intervention. However, pollution distributions (baseline and post-intervention) were wide and overlapping. Although substantial reductions in blood pressure were not observed among the entire population, a 5.9 mmHg reduction [95% confidence interval (CI): -11.3, -0.4] in systolic blood pressure was observed among women aged 40 or more years and a 4.6 mmHg reduction (95% CI: -10.0, 0.8) was observed among obese women. Results from this study provide an indication that certain subgroups may be more likely to experience improvements in blood pressure following a cookstove intervention.

White matter development in adolescence: a DTI study

Adolescence is a unique period of physical and cognitive development that includes concurrent pubertal changes and sex-based vulnerabilities. While diffusion tensor imaging (DTI) studies show white matter maturation throughout the lifespan, the state of white matter integrity specific to adolescence is not well understood as are the contributions of puberty and sex. We performed whole-brain DTI studies of 114 children, adolescents, and adults to identify age-related changes in white matter integrity that characterize adolescence. A distinct set of regions across the brain were found to have decreasing radial diffusivity across age groups. Region of interest analyses revealed that maturation was attained by adolescence in broadly distributed association and projection fibers, including those supporting cortical and brain stem integration that may underlie known enhancements in reaction time during this period. Maturation after adolescence included association and projection tracts, including prefrontal-striatal connections, known to support top-down executive control of behavior and interhemispheric connectivity. Maturation proceeded in parallel with pubertal changes to the postpubertal stage, suggesting hormonal influences on white matter development. Females showed earlier maturation of white matter integrity compared with males. Together, these findings suggest that white matter connectivity supporting executive control of behavior is still immature in adolescence.

Immaturities in reward processing and its influence on inhibitory control in adolescence

The nature of immature reward processing and the influence of rewards on basic elements of cognitive control during adolescence are currently not well understood. Here, during functional magnetic resonance imaging, healthy adolescents and adults performed a modified antisaccade task in which trial-by-trial reward contingencies were manipulated. The use of a novel fast, event-related design enabled developmental differences in brain function underlying temporally distinct stages of reward processing and response inhibition to be assessed. Reward trials compared with neutral trials resulted in faster correct inhibitory responses across ages and in fewer inhibitory errors in adolescents. During reward trials, the blood oxygen level-dependent signal was attenuated in the ventral striatum in adolescents during cue assessment, then overactive during response preparation, suggesting limitations during adolescence in reward assessment and heightened reactivity in anticipation of reward compared with adults. Importantly, heightened activity in the frontal cortex along the precentral sulcus was also observed in adolescents during reward-trial response preparation, suggesting reward modulation of oculomotor control regions supporting correct inhibitory responding. Collectively, this work characterizes specific immaturities in adolescent brain systems that support reward processing and describes the influence of reward on inhibitory control. In sum, our findings suggest mechanisms that may underlie adolescents' vulnerability to poor decision-making and risk-taking behavior.

Oculomotor abnormalities parallel cerebellar histopathology in autism

OBJECTIVE

To investigate cerebellar function in autism by measuring visually guided saccades.

METHODS

A visually guided saccade task was performed by 46 high-functioning individuals with autism with and without delayed language acquisition, and 104 age and IQ matched healthy individuals.

RESULTS

Individuals with autism had increased variability in saccade accuracy, and only those without delayed language development showed a mild saccadic hypometria. Neither autistic group showed a disturbance in peak saccade velocity or latency.

CONCLUSIONS

The observed saccadic abnormalities suggest a functional disturbance in the cerebellar vermis or its output through the fastigial nuclei, consistent with reported cerebellar histopathology in autism. The pattern of mild hypometria and variable saccade accuracy is consistent with chronic rather than acute effects of cerebellar vermis lesions reported in clinical and non-human primate studies, as might be expected in a neurodevelopmental disorder. The different patterns of oculomotor deficits in individuals with autism with and without delayed language development suggest that pathophysiology at the level of the cerebellum may differ depending on an individual's history of language development.

Neocortical system abnormalities in autism: an fMRI study of spatial working memory

OBJECTIVE

To test the hypothesis that deficits in spatial working memory in autism are due to abnormalities in prefrontal circuitry.

METHODS

Functional MRI (fMRI) at 3 T was performed in 11 rigorously diagnosed non-mentally retarded autistic and six healthy volunteers while they performed an oculomotor spatial working memory task and a visually guided saccade task.

RESULTS

Autistic subjects demonstrated significantly less task-related activation in dorsolateral prefrontal cortex (Brodmann area [BA] 9/46) and posterior cingulate cortex (BA 23) in comparison with healthy subjects during a spatial working memory task. In contrast, activation of autistic individuals was not reduced in other regions comprising the neural circuitry for spatial working memory including the cortical eye fields, anterior cingulate cortex, insula, basal ganglia, thalamus, and lateral cerebellum. Autistic subjects also did not demonstrate reduced activation in any brain regions while performing visually guided saccades.

CONCLUSION

Impairments in executive cognitive processes in autism may be subserved by abnormalities in neocortical circuitry as evidenced by decreased activation in prefrontal and posterior cingulate circuitry during a spatial working memory task.

Studies of brain and cognitive maturation through childhood and adolescence: a strategy for testing neurodevelopmental hypotheses

Although neurodevelopmental models of schizophrenia are now widely accepted, there is minimal direct human evidence of dysmaturation in schizophrenia to support this theory. This is especially the case regarding maturational changes during late childhood and adolescence, which immediately precede the typical age of onset of the disorder. By integrating new noninvasive methods of functional magnetic resonance imaging with techniques of developmental cognitive neuroscience, it is now possible to begin systematic research programs to directly test hypotheses of neurodevelopmental abnormalities in schizophrenia. In this article, we describe strategies for characterizing developmental changes taking place during the critical period of adolescence that can elucidate dysmaturation processes in schizophrenia. We emphasize the need for studies characterizing normal development before examining at-risk or clinical populations, and the potential value of using neurobehavioral and neuroimaging approaches to directly characterize the dysmaturation associated with schizophrenia.

Stimulus-response incompatibility activates cortex proximate to three eye fields

We used functional magnetic resonance imaging (fMRI) to investigate cortical activation during the performance of three oculomotor tasks that impose increasing levels of cognitive demand. (1) In a visually guided saccade (VGS) task, subjects made saccades to flashed targets. (2) In a compatible task, subjects made leftward and rightward saccades in response to foveal presentation of the uppercase words "LEFT" or "RIGHT." (3) In a mixed task, subjects made rightward saccades in response to the lowercase word "left" and leftward saccades in response to the lowercase word "right" on incompatible trials (60%). The remaining 40% of trials required compatible responses to uppercase words. The VGS and compatible tasks, when compared to fixation, activated the three cortical eye fields: the supplementary eye field (SEF), the frontal eye field (FEF), and the parietal eye field (PEF). The mixed task, when compared to the compatible task, activated three additional cortical regions proximate to the three eye fields: (1) rostral to the SEF in medial frontal cortex; (2) rostral to the FEF in dorsolateral prefrontal cortex (DLPFC); (3) rostral and lateral to the PEF in posterior parietal cortex. These areas may contribute to the suppression of prepotent responses and in holding novel visuomotor associations in working memory.

Maturation of widely distributed brain function subserves cognitive development

Cognitive and brain maturational changes continue throughout late childhood and adolescence. During this time, increasing cognitive control over behavior enhances the voluntary suppression of reflexive/impulsive response tendencies. Recently, with the advent of functional MRI, it has become possible to characterize changes in brain activity during cognitive development. In order to investigate the cognitive and brain maturation subserving the ability to voluntarily suppress context-inappropriate behavior, we tested 8-30 year olds in an oculomotor response-suppression task. Behavioral results indicated that adult-like ability to inhibit prepotent responses matured gradually through childhood and adolescence. Functional MRI results indicated that brain activation in frontal, parietal, striatal, and thalamic regions increased progressively from childhood to adulthood. Prefrontal cortex was more active in adolescents than in children or adults; adults demonstrated greater activation in the lateral cerebellum than younger subjects. These results suggest that efficient top-down modulation of reflexive acts may not be fully developed until adulthood and provide evidence that maturation of function across widely distributed brain regions lays the groundwork for enhanced voluntary control of behavior during cognitive development.

Oral agents in the management of type 2 diabetes mellitus

Despite exhaustive efforts to better manage patients with type 2 diabetes mellitus (formerly known as non-insulin-dependent diabetes mellitus), attempts at maintaining near normal blood glucose levels in these patients remains unsatisfactory. This continues to pose a real challenge to physicians as the prevalence of this disease in the United States continues to rise. Type 2 diabetes is defined as a syndrome characterized by insulin deficiency, insulin resistance and increased hepatic glucose output. Medications used to treat type 2 diabetes are designed to correct one or more of these metabolic abnormalities. Currently, there are five distinct classes of hypoglycemic agents available, each class displaying unique pharmacologic properties. These classes are the sulfonylureas, meglitinides, biguanides, thiazolidinediones and alpha-glucosidase inhibitors. In patients for whom diet and exercise do not provide adequate glucose control, therapy with a single oral agent can be tried. When choosing an agent, it is prudent to consider both patient- and drug-specific characteristics. If adequate blood glucose control is not attained using a single oral agent, a combination of agents with different mechanisms of action may have additive therapeutic effects and result in better glycemic control.

The removal of bacteria by modified natural zeolites

The removal effect of natural and modified zeolites containing different heavy metals (Ni2+, Zn2+, Fe3+ and Cu2+) on pure cultures of Escherichia coli and Staphylococcus aureus in a solid medium was evaluated in this work. These experiments were carried out in a continuous mode treating municipal wastewater. Faecal coliform species and Pseudomonas aeruginosa were identified. The rate constants of heavy metal lixiviation were determined using a first order kinetic model. The removal effect of modified natural zeolites in both a solid medium and in continuous mode showed an increased elimination of the bacterial population. The results established a decreasing order of the removal effect as follows: Cu2+ > Fe3+ > Zn2+ > Ni2+. The best performance of columns was obtained for inlet bacterial concentrations below 10(6) cells/100 ml. Most of the identified bacterial species were affected by copper modified zeolites, although Serratia marcescens presented the highest sensitivity and Klebsiella pneumoniae the greatest resistance.

Inhibitory control of attention declines more than working memory during normal aging

Changes in frontostriatal systems are believed to reduce the efficiency of executive cognitive functions during normal aging, especially the inhibitory control of attentional and behavioral responses. To characterize changes during normal aging in sensorimotor, working memory and inhibitory attentional systems, we tested 20 healthy elderly subjects (age 65-80) and 28 young adults (age 18-34) using oculomotor paradigms. Visually guided saccades of elderly subjects showed decreased peak velocity and increased reaction time, but not reduced accuracy, indicating selective age-related declines in sensorimotor systems. In an oculomotor working memory task, memory for spatial location information in elderly subjects was as accurate as in young adults. In contrast, elderly subjects demonstrated a significantly reduced ability to voluntarily inhibit eye movements toward flashed targets on an antisaccade task. These findings indicate changes in frontostriatal systems during normal aging that adversely affect volitional inhibitory processes but spare encoding and retrieval components of spatial working memory.

Physiologic and functional responses of MS patients to body cooling

OBJECTIVE

The objective of this study was to compare the responses of multiple sclerosis (MS) patients to short-term cooling therapy using three different vest configurations.

DESIGN

Each garment was used to cool 13 male and 13 female MS subjects (31-67 yr). Oral and right and left ear temperatures were logged manually every 5 min. Arm, leg, chest, and rectal temperatures, heart rate, and respiration were recorded continuously on a Biolog ambulatory monitor. Each subject was given a series of subjective and objective evaluation tests before and after cooling.

RESULTS

The Life Enhancement Technologies and Steele vests test groups had similar, significant (P < 0.01) cooling effects on oral and ear canal temperatures, which decreased approximately 0.4 degrees C and 0.3 degrees C, respectively. The Life Enhancement Technologies active liquid cooling vest produced the coldest (P < 0.01) skin temperature and provided the most improvement on subjective and objective performance measures.

CONCLUSIONS

These results show that the various garment configurations tested do not produce similar thermal responses in all MS patients. The circulating liquid cooling vest was found to be more effective than either of the two passive cooling garments tested.

Cortical networks subserving pursuit and saccadic eye movements in humans: an FMRI study

High-field (3 Tesla) functional magnetic resonance imaging (MRI) was used to investigate the cortical circuitry subserving pursuit tracking in humans and compare it to that for saccadic eye movements. Pursuit performance, relative to visual fixation, elicited activation in three areas known to contribute to eye movements in humans and in nonhuman primates: the frontal eye field, supplementary eye field, and intraparietal sulcus. It also activated three medial regions not previously identified in human neuroimaging studies of pursuit: the precuneus and the anterior and posterior cingulate cortices. All six areas were also activated during saccades. The spatial extent of activation was similar for saccades and pursuit in all but two regions: spatial extent was greater for saccades in the superior branch of the frontal eye field and greater for pursuit in posterior cingulate cortex. This set of activations for smooth pursuit parallels the network of oculomotor areas characterized in nonhuman primates and complements recent studies showing that common cortical networks subserve oculomotor functions and spatial attention in humans.

Agents for treatment of invasive fungal infections

The incidence of fungal infections continues to rise as the population of immunocompromised individuals increases. Despite the enlarging numbers of infections, there are only a few antifungal agents for treatment of deep-seated, invasive infections. These agents include amphotericin B, flucytosine, terbinafine, and several azoles. Progress has been made in understanding the role of these agents in a variety of infections and this article examines in detail these agents and their prophylactic, empiric, and therapeutic uses in invasive mycoses. This article focuses on general concepts of antifungal therapies and provides a detailed review of each antifungal agent available for treatment of deep-seated mycoses.

The use of insulin secretagogues in the treatment of type 2 diabetes

Secretatogues are a class of agents that achieve their hypoglycemic effects through stimulating insulin release. They include the sulfonylureas, repaglinide, and the investigational agent glucagon-like peptide. The secretagogue agents have been studied extensively as monotherapy and in conjunction with other classes of oral agents, including alpha-glucosidase inhibitors, bijuanides, and thiazolidinediones, for the treatment of type 2 diabetes. This article reviews the pharmacodynamic and pharmacokinetic differences of the secretagogues, as well as the most recent clinical trials. Such information should be helpful when deciding which agent or agents will yield the best glycemic control for an individual patient.

Cortical networks subserving pursuit and saccadic eye movements in humans: an FMRI study

High-field (3 Tesla) functional magnetic resonance imaging (MRI) was used to investigate the cortical circuitry subserving pursuit tracking in humans and compare it to that for saccadic eye movements. Pursuit performance, relative to visual fixation, elicited activation in three areas known to contribute to eye movements in humans and in nonhuman primates: the frontal eye field, supplementary eye field, and intraparietal sulcus. It also activated three medial regions not previously identified in human neuroimaging studies of pursuit: the precuneus and the anterior and posterior cingulate cortices. All six areas were also activated during saccades. The spatial extent of activation was similar for saccades and pursuit in all but two regions: spatial extent was greater for saccades in the superior branch of the frontal eye field and greater for pursuit in posterior cingulate cortex. This set of activations for smooth pursuit parallels the network of oculomotor areas characterized in nonhuman primates and complements recent studies showing that common cortical networks subserve oculomotor functions and spatial attention in humans.

Pursuit tracking impairments in schizophrenia and mood disorders: step-ramp studies with unmedicated patients

BACKGROUND

Eye tracking abnormalities are highly prevalent in schizophrenia, and are among the most promising phenotypic familial markers for the disorder. The neurophysiologic mechanisms underlying these disturbances and their diagnostic specificity for schizophrenia are not yet well characterized.

METHODS

This study assessed eye tracking deficits using foveopetal and foveofugal step-ramp tasks (ramps moving toward and away from central fixation after an initial step respectively) across a range of target velocities in anti-psychotic-naive schizophrenia patients, previously treated but currently unmedicated chronic schizophrenia patients, unmedicated patients with either bipolar or unipolar mood disorders, and healthy volunteers.

RESULTS

All patient groups demonstrated reduced pursuit gain in open loop and closed loop visual tracking conditions. There were no significant group differences in the latency or accuracy of catch-up saccades on foveofugal ramp tasks.

CONCLUSIONS

These findings indicate that open and closed loop pursuit eye movements are impaired during acute episodes of schizophrenia and mood disorders. The intact accuracy of saccades to moving targets in all patient groups indicates that an adequate representation of motion information is available to the saccade system. Therefore, pursuit disturbances in mood disorders and schizophrenia seem to result, at least in part, from a disturbance in sensorimotor integration in the pursuit system after the initial extraction of sensory motion information. No eye movement abnormalities observed during performance of step ramp tasks were specific to schizophrenia.

Production of transgenic tropical maize with cryIAb and cryIAc genes via microprojectile bombardment of immature embryos

To enhance the level of resistance to insects in tropical maize germplasm we have developed techniques to successfully transform elite tropical maize inbred based on the activity of specific cryI proteins against four major maize pests - corn earworm, fall armyworm, southwestern corn borer and sugarcane borer. Constructs containing cryIAb or cryIAc synthetic genes were used. To generate transgenic plants we have established methods for biolistic bombardment and the selection and regeneration of immature embryos and calli from the elite tropical lines CML72, CML216, CML323, CML327 and hybrids. Transgenic plants resistant to the herbicide Basta(TM) contained the bands for the cry, bar and gus genes as detected by Southern blot analyses. A simple leaf bioassay presented varying levels of resistance to Southwestern corn borer of transgenic tropical maize carrying the cryIAc gene. Analyses of the progenies confirmed the sexual transmission of the introduced genes and their stable expression.

A thermal physiological comparison of two HAZMAT protective ensembles with and without active convective cooling

Wearing impermeable garments for hazardous materials (HAZMAT) cleanup can often present a health and safety problem for the wearer. Even short duration cleanup activities can produce heat-stress injuries in HAZMAT workers. It was hypothesized that an internal cooling system might increase worker productivity and decrease the likelihood of heat-stress injuries in typical HAZMAT operations. Two HAZMAT protective ensembles were compared during subjects' treadmill exercise. The different ensembles were created using two different suits: a Trelleborg vapor protective suit representative of current HAZMAT suits and a prototype suit developed by engineers at the National Aeronautics and Space Administration (NASA). The two life-support systems used were a current-technology Interspiro Spirolite breathing apparatus and a liquid air breathing system that also provided convective cooling. Twelve local members of a HAZMAT team served as test subjects. They were fully instrumented to allow a complete physiological comparison of their theramal responses to the different ensembles. Results showed that cooling from the liquid air system significantly decreased thermal stress. The results of the subjective evaluations of new design features in the prototype suit were also highly favorable. Incorporation of these new design features could lead to significant operational advantages in the future.

Oculomotor evidence for neocortical systems but not cerebellar dysfunction in autism

OBJECTIVE

To investigate the functional integrity of cerebellar and frontal systems in autism using oculomotor paradigms.

BACKGROUND

Cerebellar and neocortical systems models of autism have been proposed. Courchesne and colleagues have argued that cognitive deficits such as shifting attention disturbances result from dysfunction of vermal lobules VI and VII. Such a vermal deficit should be associated with dysmetric saccadic eye movements because of the major role these areas play in guiding the motor precision of saccades. In contrast, neocortical models of autism predict intact saccade metrics, but impairments on tasks requiring the higher cognitive control of saccades.

METHODS

A total of 26 rigorously diagnosed nonmentally retarded autistic subjects and 26 matched healthy control subjects were assessed with a visually guided saccade task and two volitional saccade tasks, the oculomotor delayed-response task and the antisaccade task.

RESULTS

Metrics and dynamics of the visually guided saccades were normal in autistic subjects, documenting the absence of disturbances in cerebellar vermal lobules VI and VII and in automatic shifts of visual attention. Deficits were demonstrated on both volitional saccade tasks, indicating dysfunction in the circuitry of prefrontal cortex and its connections with the parietal cortex, and associated cognitive impairments in spatial working memory and in the ability to voluntarily suppress context-inappropriate responses.

CONCLUSIONS

These findings demonstrate intrinsic neocortical, not cerebellar, dysfunction in autism, and parallel deficits in higher order cognitive mechanisms and not in elementary attentional and sensorimotor systems in autism.

Partial left ventriculectomy (Batista procedure) in the treatment of dilated cardiomyopathy: Makati Medical Center Philippine experience

In the Philippines patients with end-stage heart disease refractory to conventional medical and surgical treatment do not have alternative choices. More than 99% of the population cannot afford cardiac transplantation. Partial left ventriculectomy (PLV) is a surgical procedure that improves cardiac function and refractory congestive heart failure (CHF). Between October 1997 and February 1998 eight patients had PLV at the Makati Medical Center, Philippines. All patients had end-stage dilated cardiomyopathy. Six patients had an idiopathic etiology, one was ischemic and one valvular. Seven of eight operations were done with the heart beating and all had transesophageal echo monitoring. An average of a 2-cm reduction in the left ventricle diameter was achieved and ejection fraction improved in all cases. There were no operative deaths. There were three late deaths. Two patients died of refractory CHF and ventricular arrhythmias and one patient died of massive cerebral hemorrhage with coumadin therapy. The five survivors are all doing well with no CHF. Follow-up two-dimensional echo shows stable left ventricular (LV) size and improved ejection fraction. Our initial experience shows that PLV, at least in the short-term, has beneficial effects in the treatment of end-stage dilated cardiomyopathy and might become an alternative to cardiac transplantation.

Cognitive functional magnetic resonance imaging at very-high-field: eye movement control

The oculomotor system, which optimizes visual interaction with the environment, provides a valuable model system for probing the building blocks of higher-order cognition. Attention shifting, working memory, and inhibition of prepotent responses can be investigated in healthy individuals and patients with brain disorders. Although the neurophysiology of the oculomotor system has been well characterized at the single-cell level in nonhuman primates, its functional architecture in humans determined by evoked response procedures and studies of patients with focal lesions has been limited. Available evidence points to a widely distributed set of neocortical and subcortical brain regions involved in the control of eye movements, including brain stem, cerebellum, thalamus, striatum, and parietal and frontal cortices. The advent of functional magnetic resonance imaging provides a noninvasive manner of localizing, at high spatial resolution, the brain systems that subserve different aspects of sensory and cognitive processes in humans. Functional magnetic resonance imaging studies have already delineated the brain systems subserving sensorimotor and cognitive control of eye movements in adult and pediatric populations. Hence, the combination of functional magnetic resonance imaging and eye movement procedures can be used to probe the integrity of the brain in neurological and psychiatric disorders as well as provide a window into the changes in brain function subserving cognitive development.

Eye tracking abnormalities in schizophrenia: evidence for dysfunction in the frontal eye fields

BACKGROUND

Eye tracking deficits are robust abnormalities in schizophrenia, but the neurobiological disturbance underlying these deficits is not known.

METHODS

To clarify the pathophysiology of eye tracking disturbances in schizophrenia, we tested 12 first-episode treatment-naive schizophrenic patients and 10 matched healthy individuals on foveofugal and foveopetal step-ramp pursuit tasks.

RESULTS

On foveopetal tasks, the initiation of pursuit eye movements was delayed in schizophrenic patients, and their steady-state pursuit gain was reduced particularly at slower target speeds (8 and 16 deg/sec). In foveofugal step-ramp tasks, their primary catch-up saccades were normal in latency and accuracy, but their postsaccadic pursuit in the first 100 msec after the primary catch-up saccade was significantly reduced even relative to their slow steady-state pursuit, especially during and immediately after an acute episode of illness.

CONCLUSIONS

These observations indicate that motion-sensitive areas in posterior temporal cortex provide sufficiently intact information about moving targets to guide accurate catch-up saccades, but that the sensory processing of motion information is not being used effectively for pursuit eye movements. Low-gain pursuit after the early stage of pursuit initiation suggests that the use of extraretinal signals about target motion (e.g., anticipatory prediction) only partially compensates for this deficit. The pattern of low-gain pursuit, impaired pursuit initiation, and intact processing of motion information for catch-up saccades but not pursuit eye movements, was consistent in the schizophrenic patients tested at five time points over a 2-year follow-up period, and implicates the frontal eye fields or their efferent or afferent pathways in the pathophysiology of eye tracking abnormalities in schizophrenia.

Dorsal cortical regions subserving visually guided saccades in humans: an fMRI study

Neurophysiological studies in non-human primates have identified saccade-related neuronal activity in cortical regions including frontal (FEF), supplementary (SEF) and parietal eye fields. Lesion and neuroimaging studies suggest a generally homologous mapping of the oculomotor system in humans; however, a detailed mapping of the precise anatomical location of these functional regions has not yet been achieved. We investigated dorsal frontal and parietal cortex during a saccade task vs. central fixation in 10 adult subjects using functional magnetic resonance imaging (fMRI). The FEF were restricted to the precentral sulcus, and did not extend anteriorly into Brodmann area 8, which has traditionally been viewed as their location in humans. The SEF were located in cortex along the interhemispheric fissure and extended minimally onto the dorsal cortical surface. Parietal activation was seen in precuneus and along the intraparietal sulcus, extending into both superior and inferior parietal lobules. These findings localize areas in frontal and parietal cortex involved in saccade generation in humans, and indicate significant differences from the macaque monkey in both frontal and parietal cortex. These differences may have functional implications for the roles these areas play in visuomotor processes.

Grating acuity and visual-field development in children with intraventricular hemorrhage

Visual development was studied in 171 preterm children who had intraventricular hemorrhage (IVH) and in 73 healthy preterm (HPT) children who did not develop IVH. Binocular grating acuity was assessed at age 1 month; monocular grating acuity and binocular visual-field extent were assessed at 4, 8, 12, 17, 24, 30, 36, and 48 months; and monocular H, O, T, V letter recognition acuity was tested at 36 and 48 months. A significantly greater proportion of IVH subjects than HPT subjects had ocular abnormalities. IVH subjects had significantly poorer grating acuity than HPT subjects at 1, 4, 8, 36, and 48 months, poorer recognition acuity than HPT subjects at 36 and 48 months, and smaller average field extent than HPT subjects at 4, 12, and 17 months. Acuity deficits were not related to grade of IVH or to the presence of periventricular leukomalacia, but may have been associated with the presence of ocular abnormalities or cerebral palsy in some IVH subjects.

Long-term grating acuity and visual-field development in preterm children who experienced bronchopulmonary dysplasia

Grating acuity, visual-field extent, and recognition acuity were examined in 77 children who had bronchopulmonary dysplasia (BPD), 101 children who had hyaline membrane disease (HMD), and 77 healthy preterm (HPT) children. None of the subjects had significant retinopathy of prematurity (ROP) or neurological abnormalities. Grating acuity and field extent were tested at 0 to 1, 4, 9, 12, 17, 24, 30, 36, and 48 months corrected age and recognition acuity was tested at 36 and 48 months corrected age. Ophthalmological examinations indicated that a greater proportion of subjects in the BPD group than in the HMD or in the HPT group had strabismus or high refractive error. However, grating acuity and field extent in the BPD group did not significantly differ from the HMD group or from the HPT group at any test age. Recognition acuity was poorer in the BPD and HMD groups than in the HPT group at both 36 and 48 months, but the difference was significant only at 36 months. These results suggest that children who experienced BPD with no significant ROP and no neurological complications show grating acuity and visual-field development comparable to that of healthy preterm children, but that recognition acuity, or the skills required to perform a recognition-acuity task, may be delayed in this BPD population.

Locomotion while load-carrying in reduced gravities

Supporting the mass of a protective suit and portable life support system (PLSS) will impose an energy requirement on planetary astronauts. To design extravehicular protective equipment for planetary missions, scientists must learn more about human physical capabilities while load-carrying in reduced gravities. In this study, an underwater treadmill and weighting system were used to simulate reduced-gravity locomotion while load-carrying. The test matrix included 3 gravity levels, 6 subjects, 2 locomotion speeds, and a range of load sizes. Energy expenditure, calculated from measured oxygen consumption, is positively correlated with gravity level, speed, and load size. The data are used to project that individuals in average physical condition will be able to walk for 8 h on the Moon while carrying up to 170% of their body mass without undue fatigue, and on Mars with up to 50% of their body mass. These approximate limits, especially for Martian gravity, may prove quite a challenge for designers of advanced protective systems. Requirements for regenerable and non-venting PLSS components have been driving the total projected masses of advanced PLSSs increasingly higher, perhaps beyond what is reasonable to carry. However, the larger mass can be beneficial in maintaining bone mass. Using Whalen's model (1988), the daily planetary walking times required to maintain bone mass were calculated for a range of carried load sizes. The calculated times were unattainably high, suggesting that some combination of loads carrying and supplemental bone maintenance measures will likely be required to maintain bone mass in reduced gravity environments.

Interobserver reliability of the Teller Acuity Card procedure in pediatric patients

PURPOSE

To compare interobserver agreement for Teller Acuity Card estimates of grating acuity between children with ocular or neurologic abnormalities, or both, and age-matched healthy preterm children.

METHODS

Subjects were 57 children, 3 to 38 months of age, who were referred for visual assessment because of diagnosed or suspected visual impairment (clinical group), and 57 healthy preterm children with no known visual or neurologic abnormalities (control group), each of whom was matched to a clinical subject, based on corrected age at the time of testing, and type of testing (monocular or binocular). Each child's grating acuity was tested by two independent observers.

RESULTS

Interobserver agreement of 1 octave or better was found in 91% of the monocular and 96% of the binocular clinical test-retest comparisons and in 95% of the monocular and 96% of the binocular control comparisons. For estimates of interocular acuity difference, interobserver agreement of 1 octave or better was found in 88% of clinical subjects and 88% of control subjects. Average test time was significantly longer in the clinical group (4.1 minutes [SD = 1.9] for monocular and 3.6 minutes [SD = 1.9] for binocular tests) than in the control group (2.5 minutes [SD = 0.9] for monocular and 2.4 minutes [SD = 0.6] for binocular tests), suggesting that children in the clinical group were more difficult to test.

CONCLUSIONS

Teller Acuity Card testing conducted by experienced testers is as reliable in children with mild to severe ocular or neurologic abnormalities as it is in healthy children, even though children with abnormalities may be more difficult to test.

Grating acuity and visual field development in infants following perinatal asphyxia

Grating acuity and visual fields were assessed in 66 children who had had perinatal asphyxia (ASPH). Also tested were 41 healthy preterm children (H-PT). Subjects were tested at birth to one month, and four, nine, 12, 17, 24, 30 and 36 months corrected age. The mean acuity scores of the ASPH group were lower than those of the H-PT group at most test ages, and significantly so at 30 and 36 months. The mean visual field size of the infants in the ASPH group was significantly smaller than that of the H-PT group at nine, 12, 30 and 36 months. No significant effects were found for preterm vs term birth, gestational age at birth, degree of asphyxia and presence of strabismus. However, central nervous system abnormalities (intraventricular haemorrhage and periventricular leukomalacia) were related to deficits in acuity and visual field size.

Development of grating acuity, letter acuity, and visual fields in small-for-gestational-age preterm infants

Visual acuity and visual field development were assessed longitudinally in 21 preterm children who were born small-for-gestational-age (SGA) and in 51 preterm children who were appropriate-for-gestational-age (AGA). Grating acuity was tested binocularly at 0-1 month and monocularly at 4, 9, 12, 18, 24, 30, 36 and 48 months corrected age, using Teller acuity cards. Visual fields were measured binocularly using kinetic perimetry at the same ages. Recognition (letter) acuity testing was attempted using the crowded HOTV test in all subjects who came in for testing at 36 and 48 months. Children in the SGA group were matched to children in the AGA group by gestational age (+/- 3 weeks) and type of perinatal medical complications. There were no significant differences in grating acuity or binocular visual field size between the SGA and AGA groups. 78% of acuity scores for individual SGA-AGA pairs fell within one octave of perfect agreement. Binocular visual field size for each SGA-AGA pair also showed good agreement. Fewer SGA than AGA subjects were able to perform recognition acuity testing, and those SGA subjects who were able to perform the test, showed consistently poorer recognition acuity than their AGA counterparts. Thus, being SGA does not pose an additional risk for the development of grating acuity or binocular visual field size over the first 4 years of life in preterm children. SGA preterm children may be at risk, however, for acuity deficits when acuity is measured with the more complex targets and the greater test distance used to measure recognition acuity.

Influence of jet impingement on color Doppler parameters of aortic regurgitation

In vitro studies have demonstrated that the characteristics of a color Doppler jet are influenced by a number of factors including jet eccentricity and jet impingement. To explore the relationship of a jet impingement and aortic regurgitant color Doppler jet parameters, jet area, width, and length were measured from apical echocardiographic views of 84 patients 4 +/- 11 days prior to catheterization and compared to angiographic grade. An impinging color jet contacted the interventricular septum or mitral valve beneath the aortic valve in the imaging plane and a nonimpinging jet did not contact the septum or mitral valve in the imaging plane. As expected, the percentage of patients with impinging jets increased with aortic regurgitation angiographic grade. Neither left ventricular chamber dimensions nor the presence of an aortic prosthesis significantly influenced the color Doppler variables. For a given angiographic grade of aortic regurgitation, impinging jets were associated with larger color Doppler jet widths (P less than 0.05) and areas (P = 0.001) than nonimpinging jets. The color Doppler area and length increased significantly with angiographic grade for nonimpinging jets (P less than 0.05) but not for impinging jets. Impinging jets are associated with larger color Doppler widths and areas than nonimpinging jets for a given grade of aortic regurgitation, possibly because of the effect of jet deflection toward an adjacent wall. Jet impinging should be considered when using color Doppler techniques to evaluate aortic regurgitation.

Grating acuity and visual field development of infants with bronchopulmonary dysplasia

The grating acuity and visual fields were assessed of 48 infants with bronchopulmonary dysplasia (BPD) who had no periventricular leukomalacia or grade III or IV intraventricular hemorrhage, and no stage 3 or greater retinopathy of prematurity. Infants were tested at four, eight, 11, 17 and 24 months corrected age, and their results were compared with those of 81 healthy preterm infants and 54 with hyaline membrane disease (HMD) that did not result in BPD. The BPD group showed no significant difference in acuity development compared with the healthy preterm and HMD groups. Infants with BPD had significantly smaller visual fields than either control group at 11 months; visual field development was similar for all groups at all other test ages. The authors conclude that infants with BPD who have no significant ocular or neurological complications show normal grating acuity and visual field development during the first two years of life.