Decision Regret among Patients with Early-stage Lung Cancer Undergoing Radiation Therapy or Surgical Resection

AIMS

Clinical equipoise exists regarding early-stage lung cancer treatment among patients as trials comparing stereotactic body radiation therapy (SBRT) and surgical resection are unavailable. Given the potential differences in treatment effectiveness and side-effects, we sought to determine the associations between treatment type, decision regret and depression.

MATERIALS AND METHODS

A multicentre, prospective study of patients with stage IA-IIA non-small cell lung cancer (NSCLC) with planned treatment with SBRT or surgical resection was conducted. Decision regret and depression were measured using the Decision Regret Scale (DRS) and Patient Health Questionnaire-4 (PHQ-4) at 3, 6 and 12 months post-treatment, respectively. Mixed linear regression modelling examined associations between treatment and decision regret adjusting for patient sociodemographics.

RESULTS

Among 211 study participants with early-stage lung cancer, 128 (61%) patients received SBRT and 83 (39%) received surgical resection. The mean age was 73 years (standard deviation = 8); 57% were female; 79% were White non-Hispanic. In the entire cohort at 3 months post-treatment, 72 (34%) and 57 (27%) patients had mild and severe decision regret, respectively. Among patients who received SBRT or surgery, 71% and 46% of patients experienced at least mild decision regret at 3 months, respectively. DRS scores increased at 6 months and decreased slightly at 12 months of follow-up in both groups. Higher DRS scores were associated with SBRT treatment (adjusted mean difference = 4.18, 95% confidence interval 0.82 to 7.54) and depression (adjusted mean difference = 3.49, 95% confidence interval 0.52 to 6.47). Neither patient satisfaction with their provider nor decision-making role concordance was associated with DRS scores.

CONCLUSIONS

Most early-stage lung cancer patients experienced at least mild decision regret, which was associated with SBRT treatment and depression symptoms. Findings suggest patients with early-stage lung cancer may not be receiving optimal treatment decision-making support. Therefore, opportunities for improved patient-clinician communication probably exist.

Birth Cohort Effects in Influenza Surveillance Data: Evidence That First Influenza Infection Affects Later Influenza-Associated Illness

BACKGROUND

The evolution of influenza A viruses results in birth cohorts that have different initial influenza virus exposures. Historically, A/H3 predominant seasons have been associated with more severe influenza-associated disease; however, since the 2009 pandemic, there are suggestions that some birth cohorts experience more severe illness in A/H1 predominant seasons.

METHODS

United States influenza virologic, hospitalization, and mortality surveillance data during 2000-2017 were analyzed for cohorts born between 1918 and 1989 that likely had different initial influenza virus exposures based on viruses circulating during early childhood. Relative risk/rate during H3 compared with H1 predominant seasons during prepandemic versus pandemic and later periods were calculated for each cohort.

RESULTS

During the prepandemic period, all cohorts had more influenza-associated disease during H3 predominant seasons than H1 predominant seasons. During the pandemic and later period, 4 cohorts had higher hospitalization and mortality rates during H1 predominant seasons than H3 predominant seasons.

CONCLUSIONS

Birth cohort differences in risk of influenza-associated disease by influenza A virus subtype can be seen in US influenza surveillance data and differ between prepandemic and pandemic and later periods. As the population ages, the amount of influenza-associated disease may be greater in future H1 predominant seasons than H3 predominant seasons.

FluChip-8G Insight: HA and NA subtyping of potentially pandemic influenza A viruses in a single assay

BACKGROUND

Global influenza surveillance in humans and animals is a critical component of pandemic preparedness. The FluChip-8G Insight assay was developed to subtype both seasonal and potentially pandemic influenza viruses in a single assay with a same day result. FluChip-8G Insight uses whole gene segment RT-PCR-based amplification to provide robustness against genetic drift and subsequent microarray detection with artificial neural network-based data interpretation.

OBJECTIVES

The objective of this study was to verify and validate the performance of the FluChip-8G Insight assay for the detection and positive identification of human and animal origin non-seasonal influenza A specimens.

METHODS

We evaluated the ability of the FluChip-8G Insight technology to type and HA and NA subtype a sample set consisting of 297 results from 180 unique non-seasonal influenza A strains (49 unique subtypes).

RESULTS

FluChip-8G Insight demonstrated a positive percent agreement ≥93% for 5 targeted HA and 5 targeted NA subtypes except for H9 (88%), and negative percent agreement exceeding 95% for all targeted subtypes.

CONCLUSIONS

The FluChip-8G Insight neural network-based algorithm used for virus identification performed well over a data set of 297 naïve sample results, and can be easily updated to improve performance on emerging strains without changing the underlying assay chemistry.

Clinical validation of the FluChip-8G Influenza A+B Assay for influenza type and subtype identification

BACKGROUND

The FluChip-8G Influenza A+B Assay is a multiplexed influenza RT-PCR and microarray-based assay with same day turnaround time, developed to subtype seasonal A viruses (H1N1pdm2009 and H3N2), distinguish B viruses as Yamagata or Victoria lineage, and is the only FDA cleared assay capable of positive identification of a wide variety of A subtypes as "non-seasonal" A viruses from human nasal specimens.

OBJECTIVE

To evaluate clinical performance of the FluChip-8G Influenza A+B Assay for detection of seasonal influenza viruses in nasal and nasopharyngeal swab specimens, and to evaluate performance for detection of non-seasonal influenza viruses using contrived samples.

STUDY DESIGN

For seasonal viruses, a multisite study of the FluChip-8G Influenza A+B Assay using prospectively and retrospectively collected nasal and nasopharyngeal swabs was performed using the FDA-cleared CDC Human Flu Dx Panel as the comparator assay. For non-seasonal viruses, testing was performed at a single site using contrived samples from 100 unique non-seasonal strains representing 41 subtypes.

RESULTS

Sensitivity (95% CI) and specificity (95% CI) for each target group, respectively, from results of 1689 clinical specimens were: seasonal H1N1pdm2009: 96.4% (87.9-99.0), 99.3% (98.8-99.6), seasonal H3N2: 91.8% (87.7-94.7), 99.7% (99.2-99.9), Influenza B Victoria: 100% (94.0-100.0), 99.9% (99.6-100.0), and Influenza B Yamagata: 95.6% (89.2-98.3), 99.9% (99.6-100.0). The sensitivity and specificity from contrived influenza A non-seasonal viruses was determined to be 99.0% (94.6-99.8) and 100% (96.7-100.0).

CONCLUSION

The FluChip-8G Influenza A+B Assay has robust sensitivity and specificity for detecting and identifying all target virus groups, including non-seasonal influenza A, with same day results.

Primordial and recycled helium isotope signatures in the mantle transition zone

Isotope compositions of basalts provide information about the chemical reservoirs in Earth's interior and play a critical role in defining models of Earth's structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme He-C-Pb-Sr isotope variability, with high ³He/⁴He ratios related to higher helium concentrations. This indicates that a less degassed, high-³He/⁴He deep mantle source infiltrates the transition zone, where it interacts with recycled material, creating the diverse compositions recorded in ocean island basalts.

Influenza passaging annotations: what they tell us and why we should listen

Influenza databases now contain over 100,000 worldwide sequence records for strains influenza A(H3N2) and A(H1N1). Although these data facilitate global research efforts and vaccine development practices, they also represent a stumbling block for researchers because of their confusing and heterogeneous annotation. Unclear passaging annotations are particularly concerning given the recent work highlighting the presence and risk of false adaptation signals introduced by cell passaging of viral isolates. With this in mind, we aim to provide a concise outline of why viruses are passaged, a clear overview of passaging annotation nomenclature currently in use, and suggestions for a standardized nomenclature going forward. Our hope is that this summary will empower researchers and clinicians alike to more easily understand a virus sample's passage history when analyzing influenza sequences.

Smokers Display Reduced Glucocorticoid Sensitivity Prior to Symptomatic Chronic Disease Development

Background

Chronic stress plays a critical role in many of today's diseases and causes of death. Tobacco use reliably increases the likelihood of chronic disease development and premature death. In addition, habitual tobacco use elevates risk of chronic inflammatory diseases, and glucocorticoid therapy is often less effective in smokers compared with nonsmokers. Taken together, smokers may develop glucocorticoid insensitivity, thereby removing the body's greatest anti-inflammatory mechanism.

Purpose

The purpose of this study was to examine glucocorticoid sensitivity among 24 smokers and 24 age-, sex-, and body mass index-matched never smokers who were clinically healthy individuals (i.e., no diagnosis or medication use for chronic diseases and normotensive).

Method

Participants visited the lab after a 12 hr fast, provided a blood sample, and completed a series of psychosocial questionnaires. Smokers continued smoking ad libitum before the lab visit. Group differences in glucocorticoid sensitivity were examined using ANCOVA and repeated with linear mixed model to account for possible dependence among immune outcomes that matching participants on age, sex, and body mass index may have introduced.

Results

Prior to clinical disease onset, smokers' peripheral blood mononuclear cells (PBMCs) exhibited reduced glucocorticoid sensitivity as well as a diminished inflammatory response to lipopolysaccharide compared with never smokers' PBMCs; results were identical regardless of statistical modeling used.

Conclusions

Cigarette smoking, a self-initiated pharmacological chronic stressor, may provide a unique opportunity to examine early wear and tear on physiological functioning that may lead to chronic disease development. Additional research into PBMCs' intracellular changes must be examined as well as repeating this study in a larger, more heterogeneous population.

PACAP controls adrenomedullary catecholamine secretion and expression of catecholamine biosynthetic enzymes at high splanchnic nerve firing rates characteristic of stress transduction in male mice

The neuropeptide PACAP (pituitary adenylate cyclase-activating polypeptide) is a cotransmitter of acetylcholine at the adrenomedullary synapse, where autonomic regulation of hormone secretion occurs. We have previously reported that survival of prolonged metabolic stress in mice requires PACAP-dependent biosynthesis and secretion of adrenomedullary catecholamines (CAs). In the present experiments, we show that CA secretion evoked by direct high-frequency stimulation of the splanchnic nerve is abolished in native adrenal slices from male PACAP-deficient mice. Further, we demonstrate that PACAP is both necessary and sufficient for CA secretion ex vivo during stimulation protocols designed to mimic stress. In vivo, up-regulation of transcripts encoding adrenomedullary CA-synthesizing enzymes (tyrosine hydroxylase, phenylethanolamine N-methyltransferase) in response to both psychogenic and metabolic stressors (restraint and hypoglycemia) is PACAP-dependent. Stressor-induced alteration of the adrenomedullary secretory cocktail also appears to require PACAP, because up-regulation of galanin mRNA is abrogated in male PACAP-deficient mice. We further show that hypoglycemia-induced corticosterone secretion is not PACAP-dependent, ruling out the possibility that glucocorticoids are the main mediators of the aforementioned effects. Instead, experiments with bovine chromaffin cells suggest that PACAP acts directly at the level of the adrenal medulla. By integrating prolonged CA secretion, expression of biosynthetic enzymes and production of modulatory neuropeptides such as galanin, PACAP is crucial for adrenomedullary function. Importantly, our results show that PACAP is the dominant adrenomedullary neurotransmitter during conditions of enhanced secretory demand.

Deep mantle cycling of oceanic crust: evidence from diamonds and their mineral inclusions

A primary consequence of plate tectonics is that basaltic oceanic crust subducts with lithospheric slabs into the mantle. Seismological studies extend this process to the lower mantle, and geochemical observations indicate return of oceanic crust to the upper mantle in plumes. There has been no direct petrologic evidence, however, of the return of subducted oceanic crustal components from the lower mantle. We analyzed superdeep diamonds from Juina-5 kimberlite, Brazil, which host inclusions with compositions comprising the entire phase assemblage expected to crystallize from basalt under lower-mantle conditions. The inclusion mineralogies require exhumation from the lower to upper mantle. Because the diamond hosts have carbon isotope signatures consistent with surface-derived carbon, we conclude that the deep carbon cycle extends into the lower mantle.

Lung cancer physicians' referral practices for palliative care consultation

BACKGROUND

Integration of palliative care with standard oncologic care improves quality of life and survival of lung cancer patients. We surveyed physicians to identify factors influencing their decisions for referral to palliative care.

METHODS

We provided a self-administered questionnaire to physicians caring for lung cancer patients at five medical centers. The questionnaire asked about practices and views with respect to palliative care referral. We used multiple regression analysis to identify predictors of low referral rates (<25%).

RESULTS

Of 155 physicians who returned survey responses, 75 (48%) reported referring <25% of patients for palliative care consultation. Multivariate analysis, controlling for provider characteristics, found that low referral rates were associated with physicians' concerns that palliative care referral would alarm patients and families [odds ratio (OR) 0.45, 95% confidence interval (CI) 0.21-0.98], while the belief that palliative care specialists have more time to discuss complex issues (OR 3.07, 95% CI 1.56-6.02) was associated with higher rates of referral.

CONCLUSIONS

Although palliative care consultation is increasingly available and recommended throughout the trajectory of lung cancer, our data indicate it is underutilized. Understanding factors influencing decisions to refer can be used to improve integration of palliative care as part of lung cancer management.

Effects of chronic immobilization stress on anxiety-like behavior and basolateral amygdala morphology in Fmr1 knockout mice

Several lines of clinical evidence support the idea that fragile X syndrome (FXS) may involve a dysregulation of hypothalamic-pituitary-adrenal axis function [Wisbeck et al. (2000) J Dev Behav Pediatr 21:278-282; Hessl et al. (2002) Psychoneuroendocrinology 27:855-872]. We had tested this idea in a mouse model of FXS (Fmr1 KO) and found that the hormonal response to acute stress was similar to that of wild-type (WT) mice [Qin and Smith (2008) Psychoneuroendocrinology 33:883-889]. We report here responses to chronic stress (CS) in Fmr1 KO mice. Following restraint for 120 min/d, 10 consecutive days, we assessed dendrite and spine morphology in basolateral amygdala (BLA). We also monitored behavior in an elevated plus maze (EPM) and the hormonal response to this novel spatial environment. After CS, mice of both genotypes underwent adrenal hypertrophy, but effects were greater in WT mice. Behavior in the EPM indicated that only WT mice had the expected increase in anxiety following CS. Serum corticosterone and adrenocorticotropic hormone (ACTH) levels were both increased following the spatial novelty of EPM, and there were no differences between genotypes in the hormonal responses. BLA dendritic branching increased proximal to the soma in WT, but in Fmr1 KO mice branching was unaffected close to the soma and slightly decreased at one point distal to the soma. Similarly, spine density on apical and basal dendrites increased in WT but decreased in Fmr1 KO mice. Spine length on apical and basal dendrites increased in WT but was unaffected in Fmr1 KO mice. These differences in behavioral response and effects on neuron morphology in BLA suggest a diminished adaptive response of Fmr1 KO mice.

MChip, a low density microarray, differentiates among seasonal human H1N1, North American swine H1N1, and the 2009 pandemic H1N1

BACKGROUND

The MChip uses data from the hybridization of amplified viral RNA to 15 distinct oligonucleotides that target the influenza A matrix (M) gene segment. An artificial neural network (ANN) automates the interpretation of subtle differences in fluorescence intensity patterns from the microarray. The complete process from clinical specimen to identification including amplification of viral RNA can be completed in <8 hours for under US$10.

OBJECTIVES

The work presented here represents an effort to expand and test the capabilities of the MChip to differentiate influenza A/H1N1 of various species origin.

METHODS

The MChip ANN was trained to recognize fluorescence image patterns of a variety of known influenza A viruses, including examples of human H1N1, human H3N2, swine H1N1, 2009 pandemic influenza A H1N1, and a wide variety of avian, equine, canine, and swine influenza viruses. Robustness of the MChip ANN was evaluated using 296 blinded isolates.

RESULTS

Training of the ANN was expanded by the addition of 71 well-characterized influenza A isolates and yielded relatively high accuracy (little misclassification) in distinguishing unique H1N1 strains: nine human A/H1N1 (88·9% correct), 35 human A/H3N2 (97·1% correct), 31 North American swine A/H1N1 (80·6% correct), 14 2009 pandemic A/H1N1 (87·7% correct), and 23 negative samples (91·3% correct). Genetic diversity among the swine H1N1 isolates may have contributed to the lower success rate for these viruses.

CONCLUSIONS

The current study demonstrates the MChip has the capability to differentiate the genetic variations among influenza viruses with appropriate ANN training. Further selective enrichment of the ANN will improve its ability to rapidly and reliably characterize influenza viruses of unknown origin.

Antigenic and genetic characteristics of swine-origin 2009 A(H1N1) influenza viruses circulating in humans

Since its identification in April 2009, an A(H1N1) virus containing a unique combination of gene segments from both North American and Eurasian swine lineages has continued to circulate in humans. The lack of similarity between the 2009 A(H1N1) virus and its nearest relatives indicates that its gene segments have been circulating undetected for an extended period. Its low genetic diversity suggests that the introduction into humans was a single event or multiple events of similar viruses. Molecular markers predictive of adaptation to humans are not currently present in 2009 A(H1N1) viruses, suggesting that previously unrecognized molecular determinants could be responsible for the transmission among humans. Antigenically the viruses are homogeneous and similar to North American swine A(H1N1) viruses but distinct from seasonal human A(H1N1).

Evolution of highly pathogenic H5N1 avian influenza viruses in Vietnam between 2001 and 2007

Highly pathogenic avian influenza (HPAI) H5N1 viruses have caused dramatic economic losses to the poultry industry of Vietnam and continue to pose a serious threat to public health. As of June 2008, Vietnam had reported nearly one third of worldwide laboratory confirmed human H5N1 infections. To better understand the emergence, spread and evolution of H5N1 in Vietnam we studied over 300 H5N1 avian influenza viruses isolated from Vietnam since their first detection in 2001. Our phylogenetic analyses indicated that six genetically distinct H5N1 viruses were introduced into Vietnam during the past seven years. The H5N1 lineage that evolved following the introduction in 2003 of the A/duck/Hong Kong/821/2002-like viruses, with clade 1 hemagglutinin (HA), continued to predominate in southern Vietnam as of May 2007. A virus with a clade 2.3.4 HA newly introduced into northern Vietnam in 2007, reassorted with pre-existing clade 1 viruses, resulting in the emergence of novel genotypes with neuraminidase (NA) and/or internal gene segments from clade 1 viruses. A total of nine distinct genotypes have been present in Vietnam since 2001, including five that were circulating in 2007. At least four of these genotypes appear to have originated in Vietnam and represent novel H5N1 viruses not reported elsewhere. Geographic and temporal analyses of H5N1 infection dynamics in poultry suggest that the majority of viruses containing new genes were first detected in northern Vietnam and subsequently spread to southern Vietnam after reassorting with pre-existing local viruses in northern Vietnam. Although the routes of entry and spread of H5N1 in Vietnam remain speculative, enhanced poultry import controls and virologic surveillance efforts may help curb the entry and spread of new HPAI viral genes.

Antigenic drift in the evolution of H1N1 influenza A viruses resulting from deletion of a single amino acid in the haemagglutinin gene

Two genetically distinct lineages of H1N1 influenza A viruses, circulated worldwide before 1994, were antigenically indistinguishable. In 1994, viruses emerged in China, including A/Beijing/262/95, with profound antigenic differences from the contemporary circulating H1N1 strains. Haemagglutinin sequence comparisons of either a predecessor virus, A/Hebei/52/94, or one representative of the cocirculating A/Bayern/7/95-like clade, A/Shenzhen/227/95, revealed a deletion of K at position 134 (H3 numbering) in the antigenic variants. The K134 deletion conferred a selective advantage to the Chinese deletion lineage, such that it eventually gave rise to currently circulating H1 viruses. Using reverse genetics to generate viruses with either an insertion or deletion of aa 134, we have confirmed that the K134 deletion, rather than a constellation of sublineage specific amino acid changes, was sufficient for the antigenic difference observed in the Chinese deletion lineage, and reinsertion of K134 revealed the requirement of a compatible neuraminidase surface glycoprotein for viral growth.

Evaluation of MChip with historic subtype H1N1 influenza A viruses, including the 1918 "Spanish Flu" strain

The robustness of a recently developed diagnostic microarray for influenza, the MChip, was evaluated with 16 historic subtype H1N1 influenza A viruses (A/H1N1), including A/Brevig Mission/1/1918. The matrix gene segments from all 16 viruses were successfully detected on the array. An artificial neural network trained with temporally related A/H1N1 viruses identified A/Brevig Mission/1/1918 as influenza virus A/H1N1 with 94% probability.

Surveillance of resistance to adamantanes among influenza A(H3N2) and A(H1N1) viruses isolated worldwide

Our previous reports demonstrated an alarming increase in resistance to adamantanes among influenza A(H3N2) viruses isolated in 2001-2005. To continue monitoring drug resistance, we conducted a comprehensive analysis of influenza A(H3N2) and A(H1N1) viruses isolated globally in 2005-2006. The results obtained by pyrosequencing indicate that 96.4% (n=761) of A(H3N2) viruses circulating in the United States were adamantane resistant. Drug resistance has reached 100% among isolates from some Asian countries. Analysis of correlation between the appearance of drug resistance and the evolutionary pathway of the hemagglutinin (HA) gene suggests at least 2 separate introductions of resistance into circulating populations that gave rise to identifiable subclades. It also indicates that resistant A(H3N2) viruses may have emerged in Asia in late 2001. Among A(H1N1) viruses isolated worldwide, resistance reached 15.5% in 2005-2006; in the United States alone, it was 4.0%. Phylogenetic analysis of the HA and M genes indicates that the acquisition of resistance in A(H1N1) viruses can be linked to a specific genetic group and was not a result of reassortment between A(H3N2) and A(H1N1) viruses. The results of the study highlight the necessity of close monitoring of resistance to existing antivirals as wells as the need for new therapeutics.

Identification of A/H5N1 influenza viruses using a single gene diagnostic microarray

In previous work, a simple diagnostic DNA microarray that targeted only the matrix gene segment of influenza A (MChip) was developed and evaluated with patient samples. In this work, the analytical utility of the MChip for detection and subtyping of an emerging virus was evaluated with a diverse set of A/H5N1 influenza viruses. A total of 43 different highly pathogenic A/H5N1 viral isolates that were collected from diverse geographic locations, including Vietnam, Nigeria, Indonesia, and Kazakhstan, representing human, feline, and a variety of avian infections spanning the time period 2003-2006 were used in this study. A probabilistic artificial neural network was developed for automated microarray image interpretation through pattern recognition. The microarray assay and subsequent subtype assignment by the artificial neural network resulted in correct identification of 24 "unknown" A/H5N1 positive samples with no false positives. Analysis of a data set composed of A/H5N1, A/H3N2, and A/H1N1 positive samples and negative controls resulted in a clinical sensitivity of 97% and a clinical specificity of 100%.

MChip: a tool for influenza surveillance

The design and characterization of a low-density microarray for subtyping influenza A is presented. The microarray consisted of 15 distinct oligonucleotides designed to target only the matrix gene segment of influenza A. An artificial neural network was utilized to automate microarray image interpretation. The neural network was trained to recognize fluorescence image patterns for 68 known influenza viruses and subsequently used to identify 53 unknowns in a blind study that included 39 human patient samples and 14 negative control samples. The assay exhibited a clinical sensitivity of 95% and clinical specificity of 92%.

Experimental evaluation of the FluChip diagnostic microarray for influenza virus surveillance

Global surveillance of influenza is critical for improvements in disease management and is especially important for early detection, rapid intervention, and a possible reduction of the impact of an influenza pandemic. Enhanced surveillance requires rapid, robust, and inexpensive analytical techniques capable of providing a detailed analysis of influenza virus strains. Low-density oligonucleotide microarrays with highly multiplexed "signatures" for influenza viruses offer many of the desired characteristics. However, the high mutability of the influenza virus represents a design challenge. In order for an influenza virus microarray to be of utility, it must provide information for a wide range of viral strains and lineages. The design and characterization of an influenza microarray, the FluChip-55 microarray, for the relatively rapid identification of influenza A virus subtypes H1N1, H3N2, and H5N1 are described here. In this work, a small set of sequences was carefully selected to exhibit broad coverage for the influenza A and B viruses currently circulating in the human population as well as the avian A/H5N1 virus that has become enzootic in poultry in Southeast Asia and that has recently spread to Europe. A complete assay involving extraction and amplification of the viral RNA was developed and tested. In a blind study of 72 influenza virus isolates, RNA from a wide range of influenza A and B viruses was amplified, hybridized, labeled with a fluorophore, and imaged. The entire analysis time was less than 12 h. The combined results for two assays provided the absolutely correct types and subtypes for an average of 72% of the isolates, the correct type and partially correct subtype information for 13% of the isolates, the correct type only for 10% of the isolates, false-negative signals for 4% of the isolates, and false-positive signals for 1% of the isolates. In the overwhelming majority of cases in which incomplete subtyping was observed, the failure was due to the nucleic acid amplification step rather than limitations in the microarray.

Robust sequence selection method used to develop the FluChip diagnostic microarray for influenza virus

DNA microarrays have proven to be powerful tools for gene expression analyses and are becoming increasingly attractive for diagnostic applications, e.g., for virus identification and subtyping. The selection of appropriate sequences for use on a microarray poses a challenge, particularly for highly mutable organisms such as influenza viruses, human immunodeficiency viruses, and hepatitis C viruses. The goal of this work was to develop an efficient method for mining large databases in order to identify regions of conservation in the influenza virus genome. From these regions of conservation, capture and label sequences capable of discriminating between different viral types and subtypes were selected. The salient features of the method were the use of phylogenetic trees for data reduction and the selection of a relatively small number of capture and label sequences capable of identifying a broad spectrum of influenza viruses. A detailed experimental evaluation of the selected sequences is described in a companion paper. The software is freely available under the General Public License at http://www.colorado.edu/chemistry/RGHP/software/.

Reassortment and evolution of current human influenza A and B viruses

During the 2001-2002 influenza season, human influenza A (H1N2) reassortant viruses were detected globally. The hemagglutinin (HA) of these H1N2 viruses was similar to that of the A/New Caledonia/20/99 (H1N1) vaccine strain both antigenically and genetically, while their neuraminidase (NA) was antigenically and genetically related to that of recent human influenza H3N2 reference viruses such as A/Moscow/10/99. All six internal genes of the H1N2 reassortants originated from an H3N2 virus. After being detected only in eastern Asia during the past 10 years, Influenza B/Victoria/2/87 lineage viruses reappeared in many countries outside of Asia in 2001. Additionally, reassortant influenza B viruses possessing an HA similar to that of B/Shandong/7/97, a recent B/Victoria/2/87 lineage reference strain, and an NA closely related to that of B/Sichuan/379/99, a recent B/Yamagata/16/88 lineage reference strain, were isolated globally and became the predominant influenza B epidemic strain. The current influenza vaccine is expected to provide good protection against H1N2 viruses because it contains A/New Caledonia/20/99 (H1N1) and A/Panama/2007/99 (H3N2) like viruses whose H1 HA or N2 NA are antigenically similar to those of recent circulating H1N2 viruses. On the other hand, widespread circulation of influenza B Victoria lineage viruses required inclusion of a strain from this lineage in influenza vaccines for the 2002-2003 season.

Propagation of pacemaker activity in the guinea-pig antrum

Cyclical periods of depolarization (slow waves) underlie peristaltic contractions involved in mixing and emptying of contents in the gastric antrum. Slow waves originate from a myenteric network of interstitial cells of Cajal (ICC-MY). In this study we have visualized the sequence and propagation of Ca(2+) transients associated with pacemaker potentials in the ICC network and longitudinal (LM) and circular muscle (CM) layers of the isolated guinea-pig gastric antrum. Gastric antrum was dissected to reveal the ICC-MY network, loaded with Fluo-4 AM and activity was monitored at 37 degrees C. Ca(2+) waves propagated throughout the ICC-MY network at an average velocity of 3.24 +/- 0.12 mm s(-1) at a frequency of 4.87 +/- 0.16 cycles min(-1) (n= 4). The propagation of the Ca(2+) wave often appeared 'step-like', with separate regions of the network being activated after variable delays. The direction of propagation was highly variable (Delta angle of propagation 44.3 +/- 10.9 deg per cycle) and was not confined to the axes of the longitudinal or circular muscle. Ca(2+) waves appeared to spread out radially from the site of initiation. The initiating Ca(2+) wave in ICC-MY was correlated to secondary Ca(2+) waves in intramuscular interstitial cells of Cajal, ICC-IM, and smooth muscle cells, and the local distortion (contraction) in a field of view. TTX (1 microm) had little effect on slow wave or pacemaker potential activity, but 2-APB (50 microm) blocked all Ca(2+) waves, indicating a pivotal role for intracellular Ca(2+) stores. Nicardipine (2 microm) eliminated the Ca(2+) transient generated by smooth muscle, but did not affect the fast upstroke associated with ICC-MY. These results indicate that slow waves follow a sequence of activation, beginning with the ICC-MY and ICC-IM network, followed later by a sustained Ca(2+) transient in the muscle layers that is responsible for contraction.

Intercontinental circulation of human influenza A(H1N2) reassortant viruses during the 2001-2002 influenza season

Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.

Molecular epidemiology of influenza A(H3N2) virus reinfections

Between 1979 and 1989, families enrolled in the Houston Family Study were prospectively monitored for influenza virus infections. Reinfection with the H3N2 subtype occurred in a number of family members, and 6 pairs of isolates (interval between collection of first and second isolate, 2-5 years) were available for molecular analysis. Changes in the hemagglutinin genes of pairs of viruses isolated from the same individuals were examined to determine the molecular basis for reinfection. The findings of this study indicate that reinfection of an individual by viruses of the same subtype may occur within a relatively short period of time when the paired strains have genetically distinct hemagglutinin genes in which amino acid changes are present in the defined antigenic sites.

Genetic and antigenic analysis of the first A/New Caledonia/20/99-like H1N1 influenza isolates reported in the Americas

From February through May of 1999, 13 cases of Influenza A virus (FLUAV), type H1N1 were reported at a Department of Defense influenza surveillance sentinel site in Lima, Peru. Genetic and antigenic analysis by hemagglutination inhibition and direct nucleotide sequencing of the HA1 region of the hemagglutinin gene were performed on two isolates, A/Peru/1641/99 and A/Peru/1798/99. Both isolates were distinct from the Bayern/7/95-like viruses circulating in the Americas and closely related to a Beijing/262/95-like variant, A/New Caledonia/20/99. With the exception of travel-related cases, the detection of these isolates represents the first appearance of New Caledonia/20/99-like viruses in the Americas. Since the characterization of these Peru isolates, a number of New Caledonia/20/99-like viruses have been reported worldwide. For the 2000/01 and 2001/02 influenza seasons, the World Health Organization (WHO) has recommended the inclusion of A/New Caledonia/20/99 as the H1N1 vaccine component for both the southern and northern hemispheres.

Stability of green fluorescent protein using luminescence spectroscopy: is GFP applicable to field analysis of contaminants?

Green fluorescent protein (GFP) was first isolated in the early 1970s for experimental use from coelenterates or the Pacific jellyfish. Aequorea victoria (Morin and Hastings, 1971). GFP has since become a favored biomarker in the photophysical analysis of molecular and cell biology because of its strong intrinsic visible fluorescence and the feasibility of fusing it to other proteins without affecting their normal functions (Creemers et al., 2000). Here we report using Bacillus subtilis expressing GFP to evaluate the influence of different environmental pH conditions on GFP fluorescence. Emission acquisitions were configured to excite at 471 nm and detect at an emission from 490 to 650 nm at 1-nm increments. Fluorescence intensity was significantly better at pH 7 (4.2 x 105 cps; P-value < 0.01) than at acid or alkaline conditions. GFP is a good biomarker for environments near netural conditions: however, GFP may be unsuitable where soils or waters are below or above pH 7 because of loss in fluorescence intensity. Alternative fluorescent markers and delivery systems must be examined in different environments to optimize responses from bioreporter molecules.

A polymeric sodium complex of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine

The ligand 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine forms a 1:1 complex with Na[BPh4], which has been structurally characterised as a one-dimensional polymeric system with an unusual coordination geometry about the sodium.

The effect of the primary structure of the polypeptide catalyst on the enantioselectivity of the Juliá-Colonna asymmetric epoxidation of enones

Epoxidation of chalcone (1), using basic hydrogen peroxide, catalysed by polypeptides with defined primary structures demonstrates that the residues in the chain near to the N-terminus determine the stereochemical outcome of the reaction.

Estimation of the number of "true" null hypotheses in multivariate analysis of neuroimaging data

The repeated testing of a null univariate hypothesis in each of many sites (either regions of interest or voxels) is a common approach to the statistical analysis of brain functional images. Procedures, such as the Bonferroni, are available to maintain the Type I error of the set of tests at a specified level. An initial assumption of these methods is a "global null hypothesis," i.e., the statistics computed on each site are assumed to be generated by null distributions. This framework may be too conservative when a significant proportion of the sites is affected by the experimental manipulation. This report presents the development of a rigorous statistical procedure for use with a previously reported graphical method, the P plot, for estimation of the number of "true" null hypotheses in the set. This estimate can then be used to sharpen existing multiple comparison procedures. Performance of the P plot method in the multiple comparison problem is investigated in simulation studies and in the analysis of autoradiographic data.

Role of muscle tone in peristalsis in guinea-pig small intestine

We investigated the involvement of muscle tone and circular muscle (CM) contraction in peristalsis in isolated guinea-pig small intestine. A segment of jejunum (approximately 13 cm) was mounted into a three chambered partitioned bath. Peristaltic waves were initiated in the oral chamber either by: (1) infusing fluid into the oral end of the jejunum; the ejected fluid was diverted via a cannula from reaching the intermediate and anal chambers, or by (2) intraluminal balloon distension of the empty oral segment. Tension of the circular muscle was measured in all three chambers. Peristaltic waves elicited by fluid infusion were evoked at an abrupt threshold. In contrast, peristaltic waves elicited by distension could be graded in amplitude according to stimulus intensity. Peristaltic waves evoked in an empty intestine exhibited similar propagation velocities to peristaltic waves associated with fluid propulsion. Nifedipine (200-400 nM) added to the intermediate chamber to block muscle contraction did not prevent peristaltic waves elicited by either stimulus from propagating into the anal chamber, although their amplitude was attenuated. Nifedipine to the site of stimulation (oral chamber) abolished peristaltic waves generated by either stimulus. Tetrodotoxin (1-2 microM), or a low Ca2+-high Mg2+ solution to the intermediate chamber abolished the propagation of peristalsis from the oral to anal chambers. In conclusion, graded peristaltic waves can occur in an empty intestine. Therefore peristalsis is not necessarily an "all-or-none" phenomenon. Peristalsis depends on the spread of nervous activity along the bowel, rather than the reactivation of neural circuits caused by displacement of fluid in the lumen. However, local muscle tone and contraction are important for the initiation and maintenance of peristaltic propagation.

Molecular correlates of influenza A H5N1 virus pathogenesis in mice

Highly pathogenic avian influenza A H5N1 viruses caused an outbreak of human respiratory illness in Hong Kong. Of 15 human H5N1 isolates characterized, nine displayed a high-, five a low-, and one an intermediate-pathogenicity phenotype in the BALB/c mouse model. Sequence analysis determined that five specific amino acids in four proteins correlated with pathogenicity in mice. Alone or in combination, these specific residues are the likely determinants of virulence of human H5N1 influenza viruses in this model.

Cerebral protein synthesis in a genetic mouse model of phenylketonuria

Local rates of cerebral protein synthesis (lCPS(leu)) were measured with the quantitative autoradiographic [1-(14)C]leucine method in a genetic mouse model (Pah(enu2)) of phenylketonuria. As in the human disease, Pah(enu2) mice have a mutation in the gene for phenylalanine hydroxylase. We compared adult homozygous (HMZ) and heterozygous (HTZ) Pah(enu2) mice with the background strain (BTBR). Arterial plasma concentrations of phenylalanine (Phe) were elevated in both HMZ and HTZ mutants by 21 times and 38%, respectively. In the total acid-soluble pool in brain concentrations of Phe were higher and other neutral amino acids lower in HMZ mice compared with either HTZ or BTBR mice indicating a partial saturation of the l-amino acid carrier at the blood brain barrier by the elevated plasma Phe concentrations. In a series of steady-state experiments, the contribution of leucine from the arterial plasma to the tRNA-bound pool in brain was found to be statistically significantly reduced in HMZ mice compared with the other groups, indicating that a greater fraction of leucine in the precursor pool for protein synthesis is derived from protein degradation. We found reductions in lCPS(leu) of about 20% throughout the brain in the HMZ mice compared with the other two groups, but no reductions in brain concentrations of tRNA-bound neutral amino acids. Our results in the mouse model suggest that in untreated phenylketonuria in adults, the partial saturation of the l-amino acid transporter at the blood-brain barrier may not underlie a reduction in cerebral protein synthesis.

Glucose transporter expression in brain: relationship to cerebral glucose utilization

Glucose is the principle energy source for mammalian brain. Delivery of glucose from the blood to the brain requires its transport across the endothelial cells of the blood-brain barrier and across the plasma membranes of neurons and glia, which is mediated by the facilitative glucose transporter proteins. The two primary glucose transporter isoforms which function in cerebral glucose metabolism are GLUT1 and GLUT3. GLUT1 is the primary transporter in the blood-brain barrier, choroid plexus, ependyma, and glia; GLUT3 is the neuronal glucose transporter. The levels of expression of both transporters are regulated in concert with metabolic demand and regional rates of cerebral glucose utilization. We present several experimental paradigms in which alterations in energetic demand and/or substrate supply affect glucose transporter expression. These include normal cerebral development in the rat, Alzheimer's disease, neuronal differentiation in vitro, and dehydration in the rat.

Selection of an adaptive test statistic for use with multiple comparison analyses of neuroimaging data

Statistical analysis of neuroimages is commonly approached with intergroup comparisons made by repeated application of univariate or multivariate tests performed on the set of the regions of interest sampled in the acquired images. The use of such large numbers of tests requires application of techniques for correction for multiple comparisons. Standard multiple comparison adjustments (such as the Bonferroni) may be overly conservative when data are correlated and/or not normally distributed. Resampling-based step-down procedures that successfully account for unknown correlation structures in the data have recently been introduced. We combined resampling step-down procedures with the Minimum Variance Adaptive method, which allows selection of an optimal test statistic from a predefined class of statistics for the data under analysis. As shown in simulation studies and analysis of autoradiographic data, the combined technique exhibits a significant increase in statistical power, even for small sample sizes (n = 8, 9, 10).

Effects of passage history and sampling bias on phylogenetic reconstruction of human influenza A evolution

In this paper we determine the extent to which host-mediated mutations and a known sampling bias affect evolutionary studies of human influenza A. Previous phylogenetic reconstruction of influenza A (H3N2) evolution using the hemagglutinin gene revealed an excess of nonsilent substitutions assigned to the terminal branches of the tree. We investigate two hypotheses to explain this observation. The first hypothesis is that the excess reflects mutations that were either not present or were at low frequency in the viral sample isolated from its human host, and that these mutations increased in frequency during passage of the virus in embryonated eggs. A set of 22 codons known to undergo such "host-mediated" mutations showed a significant excess of mutations assigned to branches attaching sequences from egg-cultured (as opposed to cell-cultured) isolates to the tree. Our second hypothesis is that the remaining excess results from sampling bias. Influenza surveillance is purposefully biased toward sequencing antigenically dissimilar strains in an effort to identify new variants that may signal the need to update the vaccine. This bias produces an excess of mutations assigned to terminal branches simply because an isolate with no close relatives is by definition attached to the tree by a relatively long branch. Simulations show that the magnitude of excess mutations we observed in the hemagglutinin tree is consistent with expectations based on our sampling protocol. Sampling bias does not affect inferences about evolution drawn from phylogenetic analyses. However, if possible, the excess caused by host-mediated mutations should be removed from studies of the evolution of influenza viruses as they replicate in their human hosts.

Genetic characterization of H3N2 influenza viruses isolated from pigs in North America, 1977-1999: evidence for wholly human and reassortant virus genotypes

Since 1998, H3N2 viruses have caused epizootics of respiratory disease in pigs throughout the major swine production regions of the U.S. These outbreaks are remarkable because swine influenza in North America had previously been caused almost exclusively by H1N1 viruses. We sequenced the full-length protein coding regions of all eight RNA segments from four H3N2 viruses that we isolated from pigs in the Midwestern U.S. between March 1998 and March 1999, as well as from H3N2 viruses recovered from a piglet in Canada in January 1997 and from a pig in Colorado in 1977. Phylogenetic analyses demonstrated that the 1977 Colorado and 1997 Ontario isolates are wholly human influenza viruses. However, the viruses isolated since 1998 from pigs in the Midwestern U.S. are reassortant viruses containing hemagglutinin, neuraminidase and PB1 polymerase genes from human influenza viruses, matrix, non-structural and nucleoprotein genes from classical swine viruses, and PA and PB2 polymerase genes from avian viruses. The HA proteins of the Midwestern reassortant swine viruses can be differentiated from those of the 1995 lineage of human H3 viruses by 12 amino acid mutations in HA1. In contrast, the Sw/ONT/97 virus, which did not spread from pig-to-pig, lacks 11 of these changes.

Cerebral glucose utilization and glucose transporter expression: response to water deprivation and restoration

The relationship between local rates of cerebral glucose utilization (ICMRglc) and glucose transporter expression was examined during physiologic activation of the hypothalamoneurohypophysial system. Three days of water deprivation, which is known to activate the hypothalamoneurohypophysial system, resulted in increased ICMRglc and increased concentrations of GLUT1 and GLUT3 in the neurohypophysis; mRNA levels of GLUT1 and GLUT3 were decreased and increased, respectively. Water deprivation also increased ICMRglc in the hypothalamic supraoptic and paraventricular nuclei; mRNA levels of GLUT1 and GLUT3 appeared to increase in these nuclei, but the changes did not achieve statistical significance. Restoration of water for 3 to 7 days reversed all observed changes in GLUT expression (protein and mRNA): restoration of water also reversed changes in ICMRglc in both the neurohypophysis and the hypothalamic nuclei. These results indicate that under conditions of neural activation and recovery, changes in ICMRglc and the levels of GLUT1 and GLUT3 are temporally correlated in the neurohypophysis and raise the possibility that GLUT1 and GLUT3 transporter expression may be regulated by chronic changes in functional activity. In addition, increases in the expression of GLUT5 mRNA in the neurohypophysis after dehydration provide evidence for involvement of microglial activation.

Effects of diazepam and ketamine administered individually or in combination on regional rates of glucose utilization in rat brain

The effects of diazepam, which acts at GABAA receptors to enhance the effects of GABA, and ketamine, a non-competitive N-methyl-D-aspartate receptor antagonist, on local rates of cerebral glucose utilization (ICMRglc) were examined in unrestrained rats. Four groups were studied: vehicle-injected controls; and ketamine-treated, diazepam-treated and combined ketamine- and diazepam-treated animals. Ketamine alone produced a heterogeneous pattern of changes in ICMRglc (e.g. significant increases in the corpus callosum, olfactory tubercle and the entire Papez circuit, in addition to other limbic areas, and significant decreases in lateral habenula and some components of the auditory system). Diazepam alone statistically significantly decreased ICMRglc in the brain as a whole and in most areas of the cerebral cortex, thalamus and limbic system. The most remarkable effects of the two drugs administered together on ICMRglc occurred in the limbic system where the dramatic increases observed with ketamine alone were prevented by treatment with diazepam.

Suppression of protein synthesis in brain during hibernation involves inhibition of protein initiation and elongation

Protein synthesis (PS) has been considered essential to sustain mammalian life, yet was found to be virtually arrested for weeks in brain and other organs of the hibernating ground squirrel, Spermophilus tridecemlineatus. PS, in vivo, was below the limit of autoradiographic detection in brain sections and, in brain extracts, was determined to be 0.04% of the average rate from active squirrels. Further, it was reduced 3-fold in cell-free extracts from hibernating brain at 37 degreesC, eliminating hypothermia as the only cause for protein synthesis inhibition (active, 0.47 +/- 0.08 pmol/mg protein per min; hibernator, 0.16 +/- 0.05 pmol/mg protein per min, P < 0.001). PS suppression involved blocks of initiation and elongation, and its onset coincided with the early transition phase into hibernation. An increased monosome peak with moderate ribosomal disaggregation in polysome profiles and the greatly increased phosphorylation of eIF2alpha are both consistent with an initiation block in hibernators. The elongation block was demonstrated by a 3-fold increase in ribosomal mean transit times in cell-free extracts from hibernators (active, 2.4 +/- 0.7 min; hibernator, 7.1 +/- 1.4 min, P < 0.001). No abnormalities of ribosomal function or mRNA levels were detected. These findings implicate suppression of PS as a component of the regulated shutdown of cellular function that permits hibernating ground squirrels to tolerate "trickle" blood flow and reduced substrate and oxygen availability. Further study of the factors that control these phenomena may lead to identification of the molecular mechanisms that regulate this state.

Effects of thiopental anesthesia on local rates of cerebral protein synthesis in rats

We have examined the effects of a surgical level of thiopental anesthesia in adult male rats on local rates of cerebral protein synthesis with the quantitative autoradiographic L-[1-14C]leucine method. The relative contribution of leucine derived from protein breakdown to the intracellular precursor amino acid pool for protein synthesis was found to be statistically significantly decreased in the anesthetized rats compared with controls. In the brain as a whole and in 30 of the 35 brain regions examined, rates of protein synthesis were decreased (1-11%) in the anesthetized rats. Decreases were statistically significant (P < or = 0.05) in the brain as a whole and in six of the regions, and they approached statistical significance in an additional 13 regions, indicating a tendency for a generalized but small effect.

Plasticity of cerebral metabolic whisker maps in adult mice after whisker follicle removal--I. Modifications in barrel cortex coincide with reorganization of follicular innervation

We investigated alterations of the metabolic whisker map of barrel cortex after the removal of the follicles of left whiskers C1, C2 and C3 in adult albino mice. The quantitative autoradiographic [14C]deoxyglucose method was used to measure local cerebral metabolic rates for glucose in barrel cortex of mice two, four, eight, 64, 160 and 250 days after the lesion. Metabolic rates were measured in three groups of animals: (i) mice with lesions that had all whiskers clipped; (ii) mice with lesions that had left whiskers B1-3 and D1-3 stimulated; and (iii) unoperated mice that had left whiskers B1-3 and D1-3 stimulated. Compared with the metabolic rates in barrels C1-3 of stimulated unoperated mice, barrels C1-3 of stimulated mice with lesions showed the first discernible increase in metabolic rate four days after the lesion. The increase became distinct at 64 days, but attained statistical significance only approximately 160 days after the lesion. The lesion per se, i.e. without whisker stimulation, caused only a small increase in metabolic rate in barrels C1-3 accounting for not more than one fourth of the increase in metabolic rate measured after whisker deflection. The removal of whisker follicles C1-3 led, therefore, to an enlargement of the metabolic representations of the adjacent whiskers into the barrels deprived by the lesion. The gradual consolidation of the alterations of the metabolic whisker map coincided with the regeneration of follicular nerves in the whiskerpad. We detected anomalous deep nerves innervating follicles surrounding the lesion at approximately 64 days, and the number of myelinated nerve fibres in the deep nerves of these follicles was increasing with increasing time after the lesion. The coincidence of peripheral and central change suggests that the reorganization of the innervation of the sensory periphery plays an important role in the persistent alterations of the cortical somatotopy in adults following a lesion in the sensory periphery.

Plasticity of cerebral metabolic whisker maps in adult mice after whisker follicle removal--II. Modifications in the subcortical somatosensory system

The follicles of whiskers C1-3 were removed from the left side of the snout of adult mice. Adjacent whiskers B1-3 and D1-3 were stimulated while local rates of glucose utilization were measured with the [14C]2-deoxyglucose method two, four, eight, 64, 160 and approximately 250 days after follicle removal. Local metabolic activity in the trigeminal sensory brainstem and somatosensory thalamus was compared with that of unoperated mice with the same stimulation and of mice with the same lesion that had all whiskers clipped. Actual rates of glucose utilization were measured in brainstem subnuclei caudalis and interpolaris whereas metabolic activation was only assessable by colour-coded imaging in brainstem nucleus principalis and in the thalamic ventrobasal complex. Whisker stimulation activated the somatotopically appropriate loci in brainstem and thalamus. In addition, the territory deprived by follicle removal was metabolically activated in subnuclei caudalis and interpolaris at all time intervals examined. The activation was statistically significant in subnucleus interpolaris at two days, indicating that the metabolic representations of whiskers neighbouring the lesion rapidly expanded into the deprived territory. Nucleus principalis showed a broad metabolic activation at two and four days that was absent at the longer time intervals examined. Instead, at approximately 250 days the metabolic representations of the whiskers adjacent to the lesion were enlarged into the deprived territory as in the subnuclei. Since metabolic whisker representation in the ventrobasal complex appeared to have changed in the same fashion, follicle removal apparently resulted in congruent modifications of the whisker map in the three nuclei of termination as well as in the thalamic relay at the longest time interval examined. Since metabolic responsiveness of the deprived barrels in barrel cortex of the same animals increased statistically significantly only several months after follicle removal, the novel neural responses in the brainstem were not effectively transmitted to barrel cortex immediately and the slowly evolving cortical modifications are more likely to be associated with regrowth of the connectivity of primary neurons. By contrast, unmasking of hitherto suppressed inputs may underlie the early expansion of metabolic whisker representation in the brainstem.

The future of Veterans Affairs Medical Centers

In the past four years, the Department of Veterans Affairs (VA) has experienced unprecedented changes in the ways it provides medical care, trains medical residents, and supports its clinical research program. For the most part, these changes have improved the quality and efficiency of care provided to veterans, and they have improved the chances that the VA will survive in an increasingly competitive medical market place. While the changes in priorities for training medical residents and funding clinical research have been designed to be more consistent with the overall mission of the VA, these changes have been stressful for many of the VA/medical school affiliations. Our challenge is to understand and manage these changes so that the many benefits that have derived from more than fifty years of VA/medical school affiliations can be retained.