Advancing youth tobacco surveillance with novel methods

Tobacco surveillance in the United States is robust but cannot be quickly modified to capture newly identified tobacco products or behaviors. We present an example of a rapidly deployed nonprobability survey using social media recruitment that collected data on rapidly changing tobacco use behaviors. We recruited 15- to 17-year old current vapers from NY, USA, using targeted social media advertisements to complete the New York Adolescent Vaping Survey (NY AVS), which asked about vaping behaviors not addressed in existing probability surveillance surveys. We used the New York Youth Risk Behavior Survey (NY YRBS) to apply calibration weights to ensure that the distribution of the demographic characteristics accurately reflected the population distribution. We found systematic differences in demographic variable distributions between the probability-based NY YRBS and the convenience sample of the NY AVS that were reconciled in the weighting calibration. We found no statistically significant differences between the NY YRBS and NY AVS estimates after calibration for two outcome variables of interest. Recruiting a sample of adolescents using social media advertising to conduct a rapid survey on vaping provided valuable data that complemented traditional surveillance surveys; this approach could be used to fill future knowledge gaps in youth tobacco surveillance.

Feasibility of a Keratin-Based Topical Cream for Radiation Dermatitis in Patients with Head and Neck Cancer: Results of a Randomized Pilot Study

PURPOSE/OBJECTIVE(S)

Acute radiation dermatitis (RD) is a frequent toxicity associated with radiotherapy (RT) for head and neck cancer (HNC). KeraStat Cream (KC), an emulsion-based wound dressing that acts as a protective barrier that promotes the healing of minor skin wounds and partial-thickness burns, has not yet been studied in patients receiving RT for HNC.

MATERIALS/METHODS

This randomized, open-label pilot study enrolled patients with HNC planned to receive definitive or postoperative RT to a total dose of at least 60 Gy. The study excluded patients with a history of prior RT, use of topical corticosteroids, scleroderma, lupus, or treatment with anti-EGFR therapy. Eligible patients were randomized to KC or routine skin care (RSC, patient choice of a variety of commercially available topical creams/lotions), applied at least twice daily during and for 1 month after RT. Assessments were performed at baseline, weekly during RT, and 1-month after RT. The primary outcome was adherence to the prescribed skin care regimen (at least 10 applications per week of treatment, starting at week 2). Secondary outcomes were the incidence rates of clinician-rated and patient-reported dermatitis (CTCAE and PRO-CTCAE grades 2+) and the Dermatologic Life Quality Index (DLQI, range 0-30 with a higher number indicating worse skin-related quality of life) at the last assessment before radiotherapy completion (end-RT).

RESULTS

Of 29 patients enrolled, 24 (n = 12 in each group) were randomized and completed the study. Most patients had stage III-IV disease (17, 71%), and the most common primary site was the oropharynx (n = 11, 46%), followed by the oral cavity (n = 7), larynx (n = 5), and sinonasal (n = 1). The median RT dose was 68 Gy (range 60-70), median skin V60 was 37.2 cc (range 1.5-107.6), and median skin V70 was 0 cc (range 0-24.9), with no differences between groups. The bilateral neck was treated in most patients (n = 19, 79%), primary site treated in 3 and unilateral neck treated in 2 patients. Most patients received concurrent chemotherapy (n = 18, 75%). Complete adherence to assigned skin care was observed in 7/12 (58%) patients in the RSC group vs. 10/12 (83%) patients in the KC group (p = 0.65). Nearly all patient-weeks were adherent: 64/67 patients in the KC group and 61/68 patients in the RSC group (p = 0.20). Incidence rates of G2+ RD were similar between the KC and RSC groups: CTCAE, 9/12 vs. 7/12 (p = 0.67); PRO-CTCAE, 10/12 vs. 8/12 (p = 0.64). When measured at end-RT, mean RD scores were similar between the KC and RSC groups: CTCAE, 1.4 vs. 1.8 (p = 0.30); PRO-CTCAE, 2.0 vs. 2.0 (p = 1); DLQI (4.8 vs. 4.6, p = 0.92). Repeated measures analysis showed no difference between arms for CTCAE (p = 0.72), PRO-CTCAE (p = 0.96), or DLQI (p = 0.78).

CONCLUSION

A randomized study of KC vs. RSC is feasible with good adherence to assigned skin care, particularly in the KC group. Future randomized trials are warranted to investigate the efficacy of this novel topical approach to RD during radiotherapy for HNC.

No evidence of risk-taking or impulsive behaviour in a person with episodic amnesia: Implications for the role of the hippocampus in future-regarding decision-making

Does advantageous decision-making require one to explicitly remember the outcome of a series of past decisions or to imagine future personal consequences of one's choices? Findings that amnesic people with hippocampal damage cannot form a clear preference for advantageous decks over many learning trials on the Iowa Gambling Task (IGT) have been taken to suggest that complex decision-making on the IGT depends on declarative (episodic) memory and hippocampal integrity. Alternatively, impaired IGT performance in amnesic individuals could be secondary to risk-taking and/or impulsive behaviour resulting from impaired episodic future thinking (i.e. prospection) known to accompany amnesia. We tested this possibility in the amnesic individual K.C. using the IGT and the Toronto Gambling Task (TGT), a novel task that dissociates impulsivity from risk-taking without placing demands on declarative memory. K.C. did not develop a preference for advantageous over disadvantageous decks on the IGT and, instead, showed a slight preference for short-term gains and an inability to acquire a more adaptive appreciation of longer-term losses. He also did not display impulsive or risk-taking behaviour on the TGT, despite a profound inability to imagine personal future experiences. These findings suggest that impaired decision-making on the IGT in amnesia is unlikely to reflect a predilection to act in the moment or failure to take future consequences into account. Instead, some forms of future-regarding decision-making may be dissociable, with performance on tasks relying on declarative learning or on episodic-constructive processes more likely to be impaired.

Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

Iodine-induced hypothyroidism in full-term infants with congenital heart disease: more common than currently appreciated?

CONTEXT

Iodine is a micronutrient essential for thyroid hormone synthesis. Thyroid hormone is critical for normal neurocognitive development in young infants, and even transient hypothyroidism can cause adverse neurodevelopmental outcomes. Both iodine deficiency and excess can cause hypothyroidism. Although iodine-induced hypothyroidism is well recognized in premature infants, full-term neonates have received less attention. Infants with congenital heart disease (CHD) are commonly exposed to excess iodine from administration of iodinated contrast agents during cardiac catheterization as well as topical application of iodine-containing antiseptics and dressings; hence, this is a vulnerable population.

OBJECTIVE

We report three cases of iodine-induced hypothyroidism in full-term neonates with CHD after cardiac angiography and topical application of iodine-containing antiseptics and dressings in the operative setting.

RESULTS

Three neonates with CHD and normal thyroid function at birth developed hypothyroidism after exposure to excess iodine. Two of these infants had transient hypothyroidism, and one had severe hypothyroidism requiring ongoing thyroid replacement therapy. All infants were asymptomatic, with hypothyroidism detected incidentally in the inpatient setting due to repeat newborn screening mandated by the long duration of hospitalization in these infants.

CONCLUSIONS

Iodine-induced hypothyroidism may be under-recognized in infants with CHD exposed to excess iodine. Systematic monitoring of thyroid function should be considered to avoid potential long-term adverse neurodevelopmental effects of even transient thyroid dysfunction in this susceptible population.

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Trajectories of Depressive Symptoms 24 Months Following Breast Cancer Diagnosis

The majority of studies on depression among cancer survivors report means or percentages which obscure the heterogeneity of women's responses to cancer. Trajectory analysis provides a more nuanced picture of different patterns of response. Purpose: To identify, in a large sample of breast cancer survivors, distinct groups of women exhibiting different patterns (trajectories) of depressive symptoms up to 24 months following a breast cancer diagnosis, and to identify characteristics associated with these patterns. Methods: 653 women within 8 months of initial breast cancer diagnosis completed questionnaires at baseline and 6, 12, and 18 months after baseline on contextual/patient characteristics, symptoms, and psychosocial variables. Chart reviews provided cancer and treatment-related data. The primary outcome was depressive symptomatology assessed by the Beck Depression Inventory (BDI). Finite mixture modeling was used to identify trajectories of depressive symptoms. Results: Based on a combination of the Bayesian Information Criterion and observation of trajectory distinctiveness, a 6-trajectory model was chosen. Almost half of the sample had a consistently very low (3.8%) or low (46%) level of depressive symptoms over time that was well below the traditional BDI cut-point of 10 thought to be indicative of clinically significant depression; 29.8% had a consistently borderline BDI score that hovered around 10; 12.1% had initially high BDI, but showed a decline over time; 7.2% showed an increased BDI over time; and a small but distinct group (1.2%) reported a chronically high BDI above 25. Women in the lower depressive symptom groups were older, had fewer physical symptoms (fatigue and pain), less rigorous chemotherapy, and lower levels of illness intrusiveness. Additional analyses also showed that to some degree, illness intrusiveness, pain, and social support scores over time paralleled BDI trajectories. Conclusions: Trajectory analysis allowed us to detect heterogeneity among women in reporting depressive symptoms following a breast cancer diagnosis. Our larger sample size identified more trajectories than other smaller studies. Mean levels of various characteristics at baseline and over time were identified that were significantly associated with each trajectory.

Deletion variant in the ADRA2B gene increases coupling between emotional responses at encoding and later retrieval of emotional memories

A deletion variant of the ADRA2B gene that codes for the α2b adrenoceptor has been linked to greater susceptibility to traumatic memory as well as attentional biases in perceptual encoding of negatively valenced stimuli. The goal of the present study was to examine whether emotional enhancements of memory associated with the ADRA2B deletion variant were predicted by encoding, as indexed by the subjectively perceived emotional salience (i.e., arousal) of events at the time of encoding. Genotyping was performed on 186 healthy young adults who rated positive, negative, and neutral scenes for level of emotional arousal and subsequently performed a surprise recognition memory task 1 week later. Experience of childhood trauma was also measured, as well as additional genetic variations associated with emotional biases and episodic memory. Results showed that subjective arousal was linked to memory accuracy and confidence for ADRA2B deletion carriers but not for non-carriers. Our results suggest that carrying the ADRA2B deletion variant enhances the relationship between arousal at encoding and subsequent memory for moderately arousing events.

Impaired event memory and recollection in a case of developmental amnesia

A current debate in the literature is whether all declarative memories and associated memory processes rely on the same neural substrate. Here, we show that H.C., a developmental amnesic person with selective bilateral hippocampal volume loss, has a mild deficit in personal episodic memory, and a more pronounced deficit in public event memory; semantic memory for personal and general knowledge was unimpaired. This was accompanied by a subtle difference in impairment between recollection and familiarity on lab-based tests of recognition memory. Strikingly, H.C.'s recognition did not benefit from a levels-of-processing manipulation. Thus, not all types of declarative memory and related processes can exist independently of the hippocampus even if it is damaged early in life.

Bronchoscopic lung-volume reduction with Exhale airway stents for emphysema (EASE trial): randomised, sham-controlled, multicentre trial

BACKGROUND

Airway bypass is a bronchoscopic lung-volume reduction procedure for emphysema whereby transbronchial passages into the lung are created to release trapped air, supported with paclitaxel-coated stents to ease the mechanics of breathing. The aim of the EASE (Exhale airway stents for emphysema) trial was to evaluate safety and efficacy of airway bypass in people with severe homogeneous emphysema.

METHODS

We undertook a randomised, double-blind, sham-controlled study in 38 specialist respiratory centres worldwide. We recruited 315 patients who had severe hyperinflation (ratio of residual volume [RV] to total lung capacity of ≥0·65). By computer using a random number generator, we randomly allocated participants (in a 2:1 ratio) to either airway bypass (n=208) or sham control (107). We divided investigators into team A (masked), who completed pre-procedure and post-procedure assessments, and team B (unmasked), who only did bronchoscopies without further interaction with patients. Participants were followed up for 12 months. The 6-month co-primary efficacy endpoint required 12% or greater improvement in forced vital capacity (FVC) and 1 point or greater decrease in the modified Medical Research Council dyspnoea score from baseline. The composite primary safety endpoint incorporated five severe adverse events. We did Bayesian analysis to show the posterior probability that airway bypass was superior to sham control (success threshold, 0·965). Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00391612.

FINDINGS

All recruited patients were included in the analysis. At 6 months, no difference between treatment arms was noted with respect to the co-primary efficacy endpoint (30 of 208 for airway bypass vs 12 of 107 for sham control; posterior probability 0·749, below the Bayesian success threshold of 0·965). The 6-month composite primary safety endpoint was 14·4% (30 of 208) for airway bypass versus 11·2% (12 of 107) for sham control (judged non-inferior, with a posterior probability of 1·00 [Bayesian success threshold >0·95]).

INTERPRETATION

Although our findings showed safety and transient improvements, no sustainable benefit was recorded with airway bypass in patients with severe homogeneous emphysema.

FUNDING

Broncus Technologies.

Lesion Explorer: a comprehensive segmentation and parcellation package to obtain regional volumetrics for subcortical hyperintensities and intracranial tissue

Subcortical hyperintensities (SH) are a commonly observed phenomenon on MRI of the aging brain (Kertesz et al., 1988). Conflicting behavioral, cognitive and pathological associations reported in the literature underline the need to develop an intracranial volumetric analysis technique to elucidate pathophysiological origins of SH in Alzheimer's disease (AD), vascular cognitive impairment (VCI) and normal aging (De Leeuw et al., 2001; Mayer and Kier, 1991; Pantoni and Garcia, 1997; Sachdev et al., 2008). The challenge is to develop processing tools that effectively and reliably quantify subcortical small vessel disease in the context of brain tissue compartments. Segmentation and brain region parcellation should account for SH subtypes which are often classified as: periventricular (pvSH) and deep white (dwSH), incidental white matter disease or lacunar infarcts and Virchow-Robin spaces. Lesion Explorer (LE) was developed as the final component of a comprehensive volumetric segmentation and parcellation image processing stream built upon previously published methods (Dade et al., 2004; Kovacevic et al., 2002). Inter-rater and inter-method reliability was accomplished both globally and regionally. Volumetric analysis showed high inter-rater reliability both globally (ICC=.99) and regionally (ICC=.98). Pixel-wise spatial congruence was also high (SI=.97). Whole brain pvSH volumes yielded high inter-rater reliability (ICC=.99). Volumetric analysis against an alternative kNN segmentation revealed high inter-method reliability (ICC=.97). Comparison with visual rating scales showed high significant correlations (ARWMC: r=.86; CHIPS: r=.87). The pipeline yields a comprehensive and reliable individualized volumetric profile for subcortical vasculopathy that includes regionalized (26 brain regions) measures for: GM, WM, sCSF, vCSF, lacunar and non-lacunar pvSH and dwSH.

The autophagy effector Beclin 1: a novel BH3-only protein

BH3 domains were originally discovered in the context of apoptosis regulators and they mediate binding of proapoptotic Bcl-2 family members to antiapoptotic Bcl-2 family members. Yet, recent studies indicate that BH3 domains do not function uniquely in apoptosis regulation; they also function in the regulation of another critical pathway involved in cellular and tissue homeostasis called autophagy. Antiapoptotic Bcl-2 homologs downregulate autophagy through interactions with the essential autophagy effector and haploinsufficient tumor suppressor, Beclin 1. Beclin 1 contains a BH3 domain, similar to that of Bcl-2 proteins, which is necessary and sufficient for binding to antiapoptotic Bcl-2 homologs and required for Bcl-2-mediated inhibition of autophagy. This review will summarize the evidence that the BH3 domain of Beclin 1 serves as a key structural motif that enables Bcl-2 to function not only as an antiapoptotic protein, but also as an antiautophagy protein.

Alcohol concentration and the ability to form intent

The ability to form intent to commit a particular act is often a significant issue in criminal litigation. Often, a complicating factor in the resolution of this issue is the presence of ethanol and drugs in the individual whose motives are to be ascertained. To determine whether an intoxicating blood ethanol concentration (BAC) in the absence of other information is sufficient to establish intent, we reviewed cases investigated by the Office of the Chief Medical Examiner, State of Maryland over a two-year period. Specifically, we identified cases of suicide with a suicide note, the presence of ethanol and the absence of other psychoactive drugs. The BACs ranged from 0.01 to 0.37 g/dL. The average BAC was 0.14 g/dL and the median BAC was 0.13 g/dL. Twenty-five of the 37 cases had a BAC greater than 0.08 g/dL. We conclude that a BAC alone is not sufficient to determine the capability of an individual to form intent to commit a particular act.

Cavitary acetabular defects treated with morselized cancellous bone graft and cementless cups

The use of impacted morselized cancellous bone grafts in conjunction with cementless hemispherical acetabular cups for treatment of AAOS type II acetabular cavitary deficiencies was evaluated in a retrospective study of 23 primary and 24 revision total hip arthroplasties, at a mean follow-up of 7.9 and 8.1 years, respectively. All primary hips received autografts, while all revision hips received allografts. Modified Harris Hip Scores for primary and revision hip replacements increased from a pre-operative mean of 37 and 47 to a postoperative mean of 90 and 86, respectively. All 23 autografts and 23 out of 24 cancellous allografts were radiographically incorporated without evidence of resorption. There were no instances of infection, component migration, or cases requiring subsequent acetabular revision. We conclude that impacted morselized cancellous bone-graft augmentation of cementless cups is a viable surgical option for AAOS type II cavitary acetabular defects.

The functional neuroanatomy of classic delayed response tasks in humans and the limitations of cross-method convergence in prefrontal function

Three classic delay tasks: spatial delayed response, delayed spatial alternation and delayed object-alternation are prototypical experimental paradigms for mapping the functional neuroanatomy of prefrontal cortex in animals. These tasks have been applied in human lesion studies, yet there have been very few studies investigating their functional neuroanatomy in healthy human subjects. We used functional magnetic resonance imaging to investigate the functional neuroanatomy of these classic paradigms (and a fourth: object delayed response) in a single sample of healthy human participants. Consistent with previous animal, human lesion, and functional neuroimaging studies, activity was observed in prefrontal and posterior parietal cortices across all three delay tasks. Task-specific activations, however, were not entirely consistent with predictions drawn from animal lesion studies. For example, delayed object-alternation activated dorsolateral prefrontal cortex, a region not generally implicated in animal lesion reports. Spatial delayed response, classically associated with the dorsolateral prefrontal cortex, did not activate this region; it rather activated posterior premotor cortices involved in response preparation, as did spatial alternation. All three tasks activated the frontopolar cortex, a region not considered crucial in animal research but associated with manipulation of internally generated information in recent human research. While cross-method convergence may be attained for lower level perceptual or motor tasks, the results of this study caution against the assumption that lesion-specific effects in animals generalize to human prefrontal cortex function.

Semiautomatic brain region extraction: a method of parcellating brain regions from structural magnetic resonance images

Structural MR imaging has become essential to the evaluation of regional brain changes in both healthy aging and disease-related processes. Several methods have been developed to measure structure size and regional brain volumes, but many of these methods involve substantial manual tracing and/or landmark identification. We present a new technique, semiautomatic brain region extraction (SABRE), for the rapid and reliable parcellation of cortical and subcortical brain regions. We combine the SABRE parcellation with tissue compartment segmentation [NeuroImage 17 (2002) 1087] to produce measures of gray matter (GM), white matter (WM), ventricular CSF, and sulcal CSF for 26 brain regions. Because SABRE restricts user input to a few easily identified landmarks, inter-rater reliability is high for all volumes, with all coefficients between 0.91 and 0.99. To assess construct validity, we contrasted SABRE-derived volumetric data from healthy young and older adults. Results from the SABRE parcellation and tissue segmentation showed significant differences in multiple brain regions in keeping with regional atrophy described in the literature by researchers using lengthy manual tracing methods. Our findings show that SABRE is a reliable semiautomatic method for assessing regional tissue volumes that provides significant timesavings over purely manual methods, yet maintains information about individual cortical landmarks.

A robust method for extraction and automatic segmentation of brain images

A new protocol is introduced for brain extraction and automatic tissue segmentation of MR images. For the brain extraction algorithm, proton density and T2-weighted images are used to generate a brain mask encompassing the full intracranial cavity. Segmentation of brain tissues into gray matter (GM), white matter (WM), and cerebral spinal fluid (CSF) is accomplished on a T1-weighted image after applying the brain mask. The fully automatic segmentation algorithm is histogram-based and uses the Expectation Maximization algorithm to model a four-Gaussian mixture for both global and local histograms. The means of the local Gaussians for GM, WM, and CSF are used to set local thresholds for tissue classification. Reproducibility of the extraction procedure was excellent, with average variation in intracranial capacity (TIC) of 0.13 and 0.66% TIC in 12 healthy normal and 33 Alzheimer brains, respectively. Repeatability of the segmentation algorithm, tested on healthy normal images, indicated scan-rescan differences in global tissue volumes of less than 0.30% TIC. Reproducibility at the regional level was established by comparing segmentation results within the 12 major Talairach subdivisions. Accuracy of the algorithm was tested on a digital brain phantom, and errors were less than 1% of the phantom volume. Maximal Type I and Type II classification errors were low, ranging between 2.2 and 4.3% of phantom volume. The algorithm was also insensitive to variation in parameter initialization values. The protocol is robust, fast, and its success in segmenting normal as well as diseased brains makes it an attractive clinical application.

Functional reorganisation of memory after traumatic brain injury: a study with H(2)(15)0 positron emission tomography

OBJECTIVE

To study the effects of moderate to severe traumatic brain injury (TBI) on the functional neuroanatomy supporting memory retrieval.

METHODS

Subjects were six patients who had sustained a moderate to severe TBI about four years before scanning and had since made a good recovery. Eleven healthy young adults matched to the patients for age and education served as controls. An established H(2)(15)0 positron emission tomography paradigm was used to elicit brain activations in response to memory retrieval. TBI patients' patterns of brain activation were compared statistically with those of control subjects. Both group and individual case data were analysed.

RESULTS

Both TBI patients and controls engaged frontal, temporal, and parietal regions known to be involved in memory retrieval, yet the TBI patients showed relative increases in frontal, anterior cingulate, and occipital activity. The hemispheric asymmetry characteristic of controls was attenuated in patients with TBI. Reduced activation was noted in the right dorsomedial thalamus. Although local aspects of this pattern were affected by the presence of focal lesions and performance differences, the overall pattern was reliable across patients and comparable to functional neuroimaging results reported for normal aging, Alzheimer's disease, and other patients with TBI.

CONCLUSIONS

The TBI patients performed memory tasks using altered functional neuroanatomical networks. These changes are probably the result of diffuse axonal injury and may reflect either cortical disinhibition attributable to disconnection or compensation for inefficient mnemonic processes.

Assessment of the acuteness of heroin deaths from the analysis of multiple blood specimens

Data was compiled from 126 morphine-involved cases investigated by the Office of the Chief Medical Examiner, State of Maryland, USA. An investigation was conducted into whether comparison of morphine concentrations from a central and peripheral site could be used to determine whether a morphine death was acute or delayed. Fifty cases were identified as 'acute' because the urine free morphine concentration by radioimmunoassay (RIA) was less than 25 ng/mL; 76 cases were classified as 'random' because they had a urine morphine concentration greater than 25 ng/mL by RIA. The average heart blood to peripheral blood morphine concentration ratio in the acute deaths was 1.40. The average heart blood to peripheral blood morphine concentration ratio in the random deaths was 1.18. Because there was considerable overlap between the two groups of data, the authors conclude that it was not possible to predict 'acute' opiate intoxication deaths versus 'delayed' deaths when the only information available is heart and peripheral blood free morphine concentrations.

Interaction between carbon monoxide and ethanol in fire fatalities

Impairment due to ethanol is clearly a risk factor in deaths due to fire. However, it is less clear whether there is a physiological interaction between ethanol and carbon monoxide (CO) that would alter the carboxyhemoglobin saturation level (COHb sat.) that accounts for death. In an attempt to explore this issue further, 196 fire fatalities investigated by the Office of the Chief Medical Examiner, State of Maryland over a 3-year period were examined. COHb sat. and blood ethanol concentrations (BAC) were tabulated. Twelve cases positive for therapeutic or abused drugs other than lidocaine or atropine were excluded; 184 cases were included. The data indicate that ethanol does not affect the COHb sat. that accounts for death, since the percentage of cases positive for ethanol at a given COHb range shows no trends. Therefore, we conclude that although ethanol remains a risk factor in fire fatalities, the risk appears to be related to the impairment that it produces as opposed to a direct interaction with CO.

Identification of genes involved in the host response to neurovirulent alphavirus infection

Single-amino-acid mutations in Sindbis virus proteins can convert clinically silent encephalitis into uniformly lethal disease. However, little is known about the host gene response during avirulent and virulent central nervous system (CNS) infections. To identify candidate host genes that modulate alphavirus neurovirulence, we utilized GeneChip Expression analysis to compare CNS gene expression in mice infected with two strains of Sindbis virus that differ by one amino acid in the E2 envelope glycoprotein. Infection with Sindbis virus, dsTE12H (E2-55 HIS), resulted in 100% mortality in 10-day-old mice, whereas no disease was observed in mice infected with dsTE12Q (E2-55 GLN). dsTE12H, compared with dsTE12Q, replicated to higher titers in mouse brain and induced more CNS apoptosis. Infection with the neurovirulent dsTE12H strain was associated with both a greater number of host genes with increased expression and greater changes in levels of host gene expression than was infection with the nonvirulent dsTE12Q strain. In particular, dsTE12H infection resulted in greater increases in the levels of mRNAs encoding chemokines, proteins involved in antigen presentation and protein degradation, complement proteins, interferon-regulated proteins, and mitochondrial proteins. At least some of these increases may be beneficial for the host, as evidenced by the demonstration that enforced expression of the antiapoptotic mitochondrial protein peripheral benzodiazepine receptor (PBR) protects neonatal mice against lethal Sindbis virus infection. Thus, our findings identify specific host genes that may play a role in the host protective or pathologic response to neurovirulent Sindbis virus infection.

Urine concentrations of ketamine and norketamine following illegal consumption

Ketamine, an anesthetic agent primarily used in veterinary medicine and pediatrics, continues to gain in popularity in the drug abuse scene or 'Rave Wave' of all-night dance clubs. The Division of Forensic Toxicology Laboratory (Office of the Armed Forces Medical Examiner) at the Armed Forces Institute of Pathology, as the primary analytical laboratory for criminal investigative agencies in the Department of Defense (DOD), has seen requests for ketamine analysis rise from 1 in 1997 to 116 in 2000. This increasing abuse has led the DOD Urine Drug Testing Laboratories to consider adding ketamine screening to their random urinalysis program. However, before ketamine testing can be implemented as standard policy, concentrations of ketamine and metabolites in urine need to be evaluated after actual drug use. There is very little information regarding the pharmacokinetics of ketamine, especially concentrations of the drug or its two major metabolites, norketamine and dehydronorketamine, that can be expected in urine. In fact, dehydronorketamine has been believed to be an analytical artifact caused by the high temperatures of gas chromatography. In this paper, we attempt to resolve this issue with the development of a liquid chromatography-mass spectrometry (LC-MS) method. The urine concentrations of ketamine, norketamine and dehydronorketamine (presumptive) detected in 33 "positive" cases received in our laboratory since 1998 are reported. Quantitations were accomplished with LC-MS. Ketamine concentrations ranged from 6 to 7744 ng/mL. Norketamine concentrations ranged from 7 to 7986 ng/mL and dehydronorketamine (presumptive) concentrations ranged from 37 to 23,239 ng/mL.

Muscarinic versus nicotinic modulation of a visual task. a pet study using drug probes

Little is known about acetylcholine (ACh) modulation of central visual processing in humans. Receptor densities in visual brain regions are differentially distributed suggesting that receptor subtypes have different functions. Using PET, we have previously described the brain regions activated by a simple pattern-flash stimulus in healthy elderly subjects. To evaluate muscarinic and nicotinic contributions to ACh modulation of visual processing, we scanned elderly subjects watching the pattern-flash stimulus during no drug, during physostigmine augmentation, and during scopolamine antagonism of physostigmine's action. These manipulations of ACh significantly altered regional cerebral blood flow (rCBF) in brain regions activated by the task. The pattern of rCBF values across drug conditions suggested that muscarinic and nicotinic effects were dissociated. Muscarinic action predominated in striate cortex (Brodmann Area, BA 17) and lateral visual association areas (BA 18, 19), while nicotinic action predominated in the thalamus and inferior parietal regions (BA 39/40). Both muscarinic and nicotinic actions increased rCBF in some regions while decreasing it in others. A parsimonious reconciliation of these results with functional anatomy suggests that muscarinic action modulates visual attribute processing, while nicotinic action modulates arousal and selective attention to the visual task.

Citalopram distribution in postmortem cases

This is a report of the analytical findings in 13 cases investigated by either the Office of the Chief Medical Examiner, State of Maryland or the Bexar County (San Antonio, TX) Medical Examiner's Office in which citalopram, a highly selective serotonin reuptake inhibitor used therapeutically as an antidepressant, was identified. In 8 of the 9 cases in which both blood and urine specimens were received, the urine citalopram concentration exceeded the blood concentration, indicating that urine is an appropriate specimen for screening citalopram use. The average liver to blood citalopram concentration ratio was 6.5 (range 3.1-13, n = 6). Three cases had blood concentrations less than 0.24 mg/L, which is in the reported antemortem therapeutic range of the drug. Eleven cases had blood concentrations less than 1.3 mg/L; in each of these cases, citalopram was determined to be an incidental finding to the ultimate cause of death. Quantitation of citalopram and the metabolite desmethylcitalopram in these cases yielded an average parent-to-metabolite ratio of 6.4.