Gender differences in medication use and cigarette smoking cessation: results from the International Tobacco Control Four Country Survey

INTRODUCTION

There is conflicting evidence for gender differences in smoking cessation, and there has been little research on gender differences in smoking cessation medication (SCM) use and effectiveness. Using longitudinal data from the International Tobacco Control Four Country Surveys (ITC-4) conducted in the United Kingdom, the United States, Canada, and Australia, we examined gender differences in the incidence of quit attempts, reasons for quitting, use of SCMs, reasons for discontinuing use of SCMs, and rates of smoking cessation.

METHODS

Data were analyzed from adult smokers participating in the ITC-4, annual waves 2006-2011 (n = 7,825), as well as a subsample of smokers (n = 1,079) who made quit attempts within 2 months of survey. Adjusted modeling utilized generalized estimating equations.

RESULTS

There were no gender differences in the likelihood of desire to quit, plans to quit, or quit attempts between survey waves. Among quit attempters, women had 31% lower odds of successfully quitting (OR = 0.69; 95% CI = 0.51, 0.94). Stratified by medication use, quit success was lower among women who did not use any SCMs (OR = 0.59; 95% CI = 0.39, 0.90), and it was no different from men when medications were used (OR = 0.73; 95% CI = 0.46, 1.16). In particular, self-selected use of nicotine patch and varenicline contributed to successful quitting among women.

CONCLUSIONS

Women may have more difficulty quitting than men, and SCMs use may help attenuate this difference.

Targeting the noradrenergic system for gender-sensitive medication development for tobacco dependence

INTRODUCTION

Tobacco use remains the leading cause of morbidity and mortality for both women and men in the United States, and women often experience poorer smoking cessation outcomes than men. Preliminary evidence suggests there are sex differences in medication effectiveness for smoking cessation. However, current medications do not take into account gender-sensitive treatment development and efficacy, underscoring the importance of this underdeveloped area of research.

METHODS

We reviewed preclinical and clinical evidence for gender differences in the inability to quit smoking by examining (a) the effect of increased negative affect and stress reactivity on smoking outcomes in women and (b) smoking for nicotine reinforcement in men. We also reviewed the current literature targeting the noradrenergic system as a novel gender-sensitive treatment strategy for tobacco dependence.

RESULTS

We hypothesize that noradrenergic agents that normalize noradrenergic activity may differentially attenuate stress reactivity in women and nicotine-related reinforcement in men, indicating that targeting the noradrenergic system for smoking cessation may be effective for both genders, with benefits operating through sex-specific mechanisms.

CONCLUSIONS

Converging lines of preclinical and clinical evidence suggest that gender-sensitive approaches to medication development for smoking cessation are a critical next step for addressing low quit rates and exacerbated health risks among women. Evidence reviewed indicates that smoking activates different brain systems modulated by noradrenergic activity in women versus men, and noradrenergic compounds may preferentially target these gender-sensitive systems.

The relationship between childhood physical and emotional abuse and smoking cessation among U.S. women and men

Childhood maltreatment is associated with increased likelihood of smoking. The purpose of the current investigation was to compare quitting motives, quit attempts, and quit success between U.S. adult smokers with or without childhood maltreatment (physical or emotional abuse), and those with or without serious psychological distress (SPD). We also examined whether SPD mediated associations between childhood maltreatment and all outcomes. We analyzed data from a 2-wave cohort telephone survey of a national U.S. sample of current cigarette smokers (n = 751). We used generalized path modeling to examine associations between maltreatment/SPD and concerns about smoking, motivation to quit, quit attempts, and smoking cessation (among the overall sample and selecting for those who made at least 1 quit attempt between waves; n = 368). Among women, maltreatment and SPD were associated with lower likelihood of quitting as well as making a successful quit attempt. SPD mediated the association between maltreatment and likelihood of successfully quitting. Women with maltreatment also had stronger concerns about smoking and motivation to quit than those without maltreatment, although there were no differences in actual quit attempts made. Neither childhood maltreatment nor SPD was associated with smoking outcomes among men. Findings suggest that female smokers with a history of childhood maltreatment are motivated to quit smoking; however, they may have more difficulty quitting smoking as a result of SPD. (PsycINFO Database Record

Consideration of sex in clinical trials of transdermal nicotine patch: a systematic review

Transdermal nicotine patch (TNP) is 1 of the most commonly used smoking cessation treatments; however, the efficacy of TNP by sex is not yet clear. The purpose of the current review was to synthesize how sex has been considered in published clinical trials of TNP for smoking cessation. The specific aims of the study were to examine the inclusion of sex in analyses of cessation outcomes, TNP-related variables (compliance, side effects), and quit-related variables (withdrawal, cravings); to review the consideration of sex-related variables (menstrual cycle phase, pregnancy); and to identify needs for future research. Potential articles published through December 31, 2013 were identified through a MEDLINE search of the terms "clinical trial," "nicotine patch," and "smoking cessation." Forty-two studies used all 3 terms and met the inclusion criteria. Approximately half of the studies reported that they considered sex in smoking cessation outcomes, with 15 studies finding no difference by sex and 7 studies finding better outcomes for men versus women. Only 5 studies reported data on outcomes by sex in their publications. No studies reported analysis of TNP compliance or withdrawal by sex. In the 1 study that examined side effects by sex, more women than men reported discontinuing TNP because of skin irritation. No study examined the association of cessation outcomes with menstrual cycle phase. There is a need to include sex in research on TNP, as well as other pharmacological and behavioral smoking treatments, to clarify the picture of treatment efficacy for women compared with men.

Spiking in auditory cortex following thalamic stimulation is dominated by cortical network activity

The state of the sensory cortical network can have a profound impact on neural responses and perception. In rodent auditory cortex, sensory responses are reported to occur in the context of network events, similar to brief UP states, that produce "packets" of spikes and are associated with synchronized synaptic input (Bathellier et al., 2012; Hromadka et al., 2013; Luczak et al., 2013). However, traditional models based on data from visual and somatosensory cortex predict that ascending sensory thalamocortical (TC) pathways sequentially activate cells in layers 4 (L4), L2/3, and L5. The relationship between these two spatio-temporal activity patterns is unclear. Here, we used calcium imaging and electrophysiological recordings in murine auditory TC brain slices to investigate the laminar response pattern to stimulation of TC afferents. We show that although monosynaptically driven spiking in response to TC afferents occurs, the vast majority of spikes fired following TC stimulation occurs during brief UP states and outside the context of the L4>L2/3>L5 activation sequence. Specifically, monosynaptic subthreshold TC responses with similar latencies were observed throughout layers 2-6, presumably via synapses onto dendritic processes located in L3 and L4. However, monosynaptic spiking was rare, and occurred primarily in L4 and L5 non-pyramidal cells. By contrast, during brief, TC-induced UP states, spiking was dense and occurred primarily in pyramidal cells. These network events always involved infragranular layers, whereas involvement of supragranular layers was variable. During UP states, spike latencies were comparable between infragranular and supragranular cells. These data are consistent with a model in which activation of auditory cortex, especially supragranular layers, depends on internally generated network events that represent a non-linear amplification process, are initiated by infragranular cells and tightly regulated by feed-forward inhibitory cells.

What is the evidence for hardening in the cigarette smoking population? Trends in nicotine dependence in the U.S., 2002-2012

BACKGROUND

It is unclear whether declines in cigarette smoking in the U.S. have resulted in a hardened population of "hardcore" smokers. We studied changes in nicotine dependence severity from 2002 to 2012, using data from the National Survey on Drug Use and Health.

METHODS

We used generalized non-linear factor analysis to examine whether individual Nicotine Dependence Syndrome Scale (NDSS) items functioned differently over time, and whether average NDSS scores changed in a sample of 130,637 current smokers. We also examined trends for individual NDSS sub-scales and whether trends were moderated by tobacco consumption and socio-demographic factors.

RESULTS

Consumption levels and dependence severity both declined over the study period. This decline was driven by priority (e.g., avoiding smoke-free locations) and tolerance dimensions of dependence, while drive (e.g., craving and smoking to relieve negative affect) and continuity (e.g., stability) of smoking did not change. Declines for tolerance were greatest among those without serious psychological distress and among middle-aged smokers. Drive and continuity increased among women and low income smokers.

CONCLUSIONS

We did not find evidence of hardening at the population level for smokers in the U.S., 2002-2012. However, there is evidence of hardening when considering drive and continuity-related nicotine dependence among women and low-income smokers, suggesting these sub-groups are experiencing greater severity of craving, smoking to relieve negative affect, and regularity of smoking despite reduced consumption.

Couples' marijuana use is inversely related to their intimate partner violence over the first 9 years of marriage

Research on the association between marijuana use and intimate partner violence (IPV) has generated inconsistent findings, and has been primarily based on cross-sectional data. We examined whether husbands' and wives' marijuana use predicted both husbands' and wives' IPV perpetration over the first 9 years of marriage (Wave 1, n = 634 couples). We also examined moderation by antisocial behavior, the spouse's marijuana use, and whether IPV was reported during the year before marriage. These predictive associations were calculated using a time-lagged multivariate generalized multilevel model, simultaneously estimating predictors of husband and wife IPV. In fully adjusted models, we found that more frequent marijuana use by husbands and wives predicted less frequent IPV perpetration by husbands. Husbands' marijuana use also predicted less frequent IPV perpetration by wives. Moderation analyses demonstrated that couples in which both spouses used marijuana frequently reported the least frequent IPV perpetration. There was a significant positive association between wives' marijuana use and wives' IPV perpetration, but only among wives who had already reported IPV perpetration during the year before marriage. These findings suggest there may be an overall inverse association between marijuana use and IPV perpetration in newly married couples, although use may be associated with greater risk of perpetration among women with a history of IPV perpetration.

Super Bowl Sunday: risky business for at-risk (male) drinkers?

BACKGROUND

Major sporting events and other festive occasions are typically associated with alcohol consumption; however, little is known about risky drinking during events such as the "Super Bowl."

OBJECTIVES

We sought to determine whether drinking on Super Bowl Sunday differed from Saturdays (the heaviest drinking day of the week) surrounding the date of the Super Bowl among at-risk drinkers.

METHODS

Heavy drinking participants (N = 208) were recruited via advertisements for a 2-year prospective study of drinking behaviors. From this larger sample, 196 were selected for whom the date of the Super Bowl was included in their daily alcohol consumption reports (including reports of abstinence on those days) for 2006, 2007, and/or 2008. Participants' average age was 36.4 (SD = 12.9); 49.5% were women. Participants at the point of recruitment were not seeking treatment and had not been in alcohol treatment in the past year.

RESULTS

Analyses using multilevel modeling comparing Super Bowl Sunday to Saturdays indicated that men drank more alcohol on Super Bowl Sunday across all 3 years, whereas women's drinking was higher in only one of the 3 years. CONCLUSIONS/IMPORTANCE: These findings suggest that heavy drinking during the Super Bowl (and in association with other sporting events), particularly among men, warrants additional attention due to the potential for deleterious public health consequences.

Crime and psychiatric disorders among youth in the US population: an analysis of the National Comorbidity Survey-Adolescent Supplement

OBJECTIVE

Current knowledge regarding psychiatric disorders and crime in youth is limited to juvenile justice and community samples. This study examined relationships between psychiatric disorders and self-reported crime involvement in a sample of youth representative of the US population.

METHOD

The National Comorbidity Survey-Adolescent Supplement (N = 10,123; ages 13-17 years; 2001-2004) was used to examine the relationship between lifetime DSM-IV-based diagnoses, reported crime (property, violent, other), and arrest history. Logistic regression compared the odds of reported crime involvement with specific psychiatric disorders to those without any diagnoses, and examined the odds of crime by psychiatric comorbidity.

RESULTS

Prevalence of crime was 18.4%. Youth with lifetime psychiatric disorders, compared to no disorders, had significantly greater odds of crime, including violent crime. For violent crime resulting in arrest, conduct disorder (CD) (odds ratio OR = 57.5; 95% CI = 30.4, 108.8), alcohol use disorders (OR = 19.5; 95% CI = 8.8, 43.2), and drug use disorders (OR = 16.1; 95% CI = 9.3, 27.7) had the greatest odds with similar findings for violent crime with no arrest. Psychiatric comorbidity increased the odds of crime. Youth with 3 or more diagnoses (16.0% of population) accounted for 54.1% of those reporting arrest for violent crime. Youth with at least 1 diagnosis committed 85.8% of crime, which was reduced to 67.9% by removing individuals with CD. Importantly, 88.2% of youth with mental illness reported never having committed any crime.

CONCLUSION

Our findings highlight the importance of improving access to mental health services for youthful offenders in community settings, given the substantial associations found between mental illness and crime in this nationally representative epidemiological sample.

Smoking and mental illness in the U.S. population

OBJECTIVES

Those with any psychiatric diagnosis have substantially greater rates of smoking and are less likely to quit smoking than those with no diagnosis. Using nationally representative data, we sought to provide estimates of smoking and longitudinal cessation rates by specific psychiatric diagnoses and mental health service use.

DESIGN AND PARTICIPANTS

Data were analysed from a two-wave cohort survey of a U.S. nationally representative sample (non-institutionalised adults): the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002, n=43,093; 2004-2005, n=34,653).

MAIN OUTCOME MEASURES

We examined smoking rates (lifetime, past year and past year heavy) and cross-sectional quit rates among those with any lifetime or past year psychiatric diagnosis (DSM-IV). Importantly, we examined longitudinal quit rates and conducted analyses by gender and age categories.

RESULTS

Those with any current psychiatric diagnosis had 3.23 (95% CI 3.11 to 3.35) times greater odds of currently smoking than those with no diagnosis, and were 25% less likely to have quit by follow-up (95% CI 20% to 30%). Prevalence varied by specific diagnoses (32.4% to 66.7%) as did cessation rates (10.3% to 17.9%). Comorbid disorders were associated with higher proportions of heavy smoking. Treatment use was associated with greater prevalence of smoking and lower likelihood of cessation.

CONCLUSIONS

Those with psychiatric diagnoses remained much more likely to smoke and less likely to quit, with rates varying by specific diagnosis. Our findings highlight the need to improve our ability to address smoking and psychiatric comorbidity both within and outside of healthcare settings. Such advancements will be vital to reducing mental illness-related disparities in smoking and continuing to decrease tobacco use globally.

Are statewide restaurant and bar smoking bans associated with reduced cigarette smoking among those with mental illness?

BACKGROUND

Smoke-free air laws have effectively reduced cigarette consumption at the population level; however, the influence of these policies on smoking among those with mental illness is unclear. We examined whether associations between statewide restaurant/bar smoking bans and cigarette smoking varied by psychiatric diagnoses and gender.

METHODS

We analyzed data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC, Wave 1: 2001-2002; Wave 2: 2004-2005; n = 7,317 smokers). All analyses were stratified by gender. We examined whether tobacco cessation was associated with the interaction between ban implementation and Wave 1 psychiatric diagnoses (alcohol use disorder [AUD], anxiety disorder [AD], or mood disorder), adjusting for relevant covariates. Among those who continued to use tobacco at Wave 2, we examined associations between Wave 2 cigarettes per day (CPD) and the diagnoses × ban interactions, controlling for Wave 1 CPD and other relevant covariates.

RESULTS

Among men with an AUD and women with an AD, ban implementation was associated with 6% and 10% greater probability of tobacco cessation at Wave 2, respectively. Among men in the overall sample, ban implementation was associated with smoking 0.8 fewer CPD at Wave 2. Associations with CPD were nonsignificant among women. Interactions between ban implementation and psychiatric diagnoses were also nonsignificant when examining CPD, suggesting consistent reductions in CPD among men but not among women.

CONCLUSIONS

This study provided the first evidence that statewide restaurant/bar smoking bans may be associated with reduced smoking among those with select psychiatric conditions.

Cigarette smoking and mental illness: a study of nicotine withdrawal

OBJECTIVES

We compared prevalence, severity, and specific symptom profiles for nicotine withdrawal across categories of mental illness. We also examined the influence of nicotine withdrawal on efforts to quit smoking among those with mental illness.

METHODS

We analyzed data from 2 sources: wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions, limiting the sample to current smokers (2001-2002; n = 9913); and a 2-wave cohort telephone survey of a national sample of adult smokers (2004-2006; n = 751).

RESULTS

Mental illness was associated with a substantially greater likelihood of nicotine withdrawal syndrome; approximately 44% of nicotine withdrawal syndrome diagnoses were attributable to mental illness. Symptom profiles were highly comparable between mental illness categories, although anxiety-related symptoms were better markers of withdrawal for those with an internalizing disorder. Smokers with mental illness were motivated to quit but were less likely to be successful in their quit attempts, and both dependence and withdrawal independently accounted for this lower likelihood of success.

CONCLUSIONS

Nicotine withdrawal may be a particularly important target for intervention among those with mental illness who smoke cigarettes.

Concordant and discordant alcohol, tobacco, and marijuana use as predictors of marital dissolution

This study examined concordant and discrepant alcohol, tobacco, and marijuana use among couples to determine whether they predicted marital separation or divorce over 9 years. The study recruited 634 couples as they applied for their marriage licenses; we assessed them at that time and reassessed them with mailed questionnaires at their first, second, fourth, seventh, and ninth wedding anniversaries. Approximately 60% of the men and women were European American, and approximately 33% were African American. The frequency of drinking to intoxication and binge drinking (more than 5 drinks in an occasion) was assessed, as was the use of cigarettes and marijuana. At each assessment, each member of the couple was asked about the occurrence of marital separations and divorce. Bivariate analyses indicated that tobacco and marijuana use, whether discrepant or concordant, were associated with marital disruptions. However, discrepant heavy drinking was associated with disruptions, but concordant heavy drinking was not. Concordant and discordant marijuana use were not associated with divorce when analyses controlled for alcohol and tobacco use. Concordant and discordant tobacco use was not associated with divorce when analyses controlled for sociodemographic and personality factors. However, discrepant alcohol use was related to divorce after controlling for the other substances in 1 analysis and after controlling for the sociodemographic factors in a separate analysis. Tobacco and marijuana use were related to divorce through their associations with other variables. However, results suggest that discrepant alcohol use may lead to marital disruptions and should be addressed with couples seeking marital treatment.

Marijuana withdrawal and aggression among a representative sample of U.S. marijuana users

BACKGROUND

Previous laboratory-based research suggests that withdrawal from marijuana may cause increased aggression. It is unclear whether this finding extends beyond the laboratory setting to the general population of marijuana users. The purpose of this study was to test a cross-sectional association between marijuana withdrawal symptoms and aggression among a representative sample of U.S. adult marijuana users, and to test whether this association was moderated by previous history of aggression.

METHODS

Data were analyzed from the National Epidemiologic Survey on Alcohol and Related Conditions. Wave Two data (2004-2005) were used for all variables except for history of aggression, which was assessed during the Wave One interview (2001-2002). Two outcomes were examined: self-report general aggression and relationship aggression. Odds ratios for aggression based on withdrawal symptoms and the interaction between withdrawal symptoms and history of aggression were calculated using logistic regression, adjusting for covariates and accounting for the complex survey design.

RESULTS

Among marijuana users with a history of aggression, marijuana withdrawal was associated with approximately 60% higher odds of past year relationship aggression (p<0.05). There was no association between withdrawal symptoms and relationship aggression among those without a history of aggression, and no association with general aggression regardless of history of aggression.

CONCLUSIONS

The findings from this study support the notion that laboratory-based increases in aggression due to marijuana withdrawal extend to the general population of marijuana users who have a previous history of aggression.

Effects of a complete smoking ban on inpatients at an intermediate to long-term psychiatric facility

The majority of research on reactions to smoking bans in psychiatric facilities focuses on staff feedback in acute inpatient settings. The purpose of this pilot study was to assess inpatient attitudes about a complete smoking ban in an intermediate to long-term psychiatric facility. One hundred inpatients were surveyed via questionnaire. Inpatients reported changes in smoking and improvements in health as a result of the ban, despite evidence of non-compliant smoking at the facility. There was evidence that inpatients perceived others' attitudes about the ban to be worse than reality. The findings from this pilot study suggest that consequences of smoking bans in psychiatric facilities are not as negative as some perceive. Smoking bans in intermediate to long-term settings may result in improvements in health among both smoking and non-smoking patients.

Women ending marriage to a problem drinking partner decrease their own risk for problem drinking

AIMS

  Marital dissolution is associated with increased risk of problematic drinking. However, marriage to a problem drinker also increases this risk, and ending this type of relationship may actually decrease risk of problematic drinking. This study tested whether women ending their marriage to a problem drinker exhibited improvements in drinking.

DESIGN

  National Epidemiologic Survey on Alcohol and Related Conditions, a two-wave nationally representative survey of the US adult population.

SETTING

  In-person interviews conducted in US households.

PARTICIPANTS

  Females married or living as if married at wave 1 at least 18 years of age.

MEASUREMENTS

  Socio-demographics, drinking frequency, drinking quantity, alcohol use disorders, problem drinking, partner problem drinking and relationship dissolution.

FINDINGS

  Ending marriage to a non-problem drinker predicted increased frequency of drinking [risk ratio (RR) = 1.55; 95% confidence interval (CI) = 1.43, 1.67], heavier drinking (RR = 1.30; 95% CI = 1.71, 1.45), more problematic drinking (RR = 2.45; 95% CI = 2.17, 2.77) and a greater likelihood of use disorder diagnosis [odds ratio (OR) = 2.2; 95% CI = 1.67, 2.91]. Ending a relationship with a problem drinker predicted less frequent drinking (RR = 0.94; 95% CI = 0.90, 0.98), less heavy drinking (RR = 0.84; 95% CI = 0.78, 0.90) and fewer alcohol-related problems (RR = 0.77; 95% CI = 0.62, 0.95).

CONCLUSIONS

  Ending a marriage with a husband who drinks problematically may decrease risk of alcohol-related problems among women, substantiating the need for alcohol treatments to address a problem drinking partner.

Thalamocortical projections to rat auditory cortex from the ventral and dorsal divisions of the medial geniculate nucleus

The ventral and dorsal medial geniculate (MGV and MGD) constitute the major auditory thalamic subdivisions providing thalamocortical inputs to layer IV and lower layer III of auditory cortex. No quantitative evaluation of this projection is available. Using biotinylated dextran amine (BDA)/biocytin injections, we describe the cortical projection patterns of MGV and MGD cells. In primary auditory cortex the bulk of MGV axon terminals are in layer IV/lower layer III with minor projections to supragranular layers and intermediate levels in infragranular layers. MGD axons project to cortical regions designated posterodorsal (PD) and ventral (VA) showing laminar terminal distributions that are quantitatively similar to the MGV-to-primary cortex terminal distribution. At the electron microscopic level MGV and MGD terminals are non-γ-aminobutyric acid (GABA)ergic with MGD terminals in PD and VA slightly but significantly larger than MGV terminals in primary cortex. MGV/MGD terminals synapse primarily onto non-GABAergic spines/dendrites. A small number synapse on GABAergic structures, contacting large dendrites or cell bodies primarily in the major thalamocortical recipient layers. For MGV projections to primary cortex or MGD projections to PD or VA, the non-GABAergic postsynaptic structures at each site were the same size regardless of whether they were in supragranular, granular, or infragranular layers. However, the population of MGD terminal-recipient structures in VA were significantly larger than the MGD terminal-recipient structures in PD or the MGV terminal-recipient structures in primary cortex. Thus, if terminal and postsynaptic structure size indicate strength of excitation then MGD to VA inputs are strongest, MGD to PD intermediate, and MGV to primary cortex the weakest.

Intimate partner violence and specific substance use disorders: findings from the National Epidemiologic Survey on Alcohol and Related Conditions

The association between substance use and intimate partner violence (IPV) is robust. It is less clear how the use of specific substances relates to relationship violence. This study examined IPV perpetration and victimization related to the following specific substance use disorders: alcohol, cannabis, cocaine, and opioid. The poly substance use of alcohol and cocaine, as well as alcohol and marijuana, were also examined. Data were analyzed from wave two of the National Epidemiologic Survey on Alcohol and Related Conditions (2004-2005). Associations between substance use disorders and IPV were tested using logistic regression models while controlling for important covariates and accounting for the complex survey design. Alcohol use disorders and cocaine use disorders were most strongly associated with IPV perpetration, while cannabis use disorders and opioid use disorders were most strongly associated with IPV victimization. A diagnosis of both an alcohol use disorder and cannabis use disorder decreased the likelihood of IPV perpetration compared to each individual substance use disorder. A diagnosis of both an alcohol use disorder and cocaine use disorder increased likelihood of reporting IPV perpetration compared with alcohol use disorders alone but decreased likelihood of perpetration compared with a cocaine use disorder diagnosis alone. Overall, substance use disorders were consistently related to intimate partner violence after controlling for important covariates. These results provide further evidence for the important link between substance use disorders and IPV and add to our knowledge of which specific substances may be related to relationship violence.

Descending projections from extrastriate visual cortex modulate responses of cells in primary auditory cortex

Primary sensory cortical responses are modulated by the presence or expectation of related sensory information in other modalities, but the sources of multimodal information and the cellular locus of this integration are unclear. We investigated the modulation of neural responses in the murine primary auditory cortical area Au1 by extrastriate visual cortex (V2). Projections from V2 to Au1 terminated in a classical descending/modulatory pattern, with highest density in layers 1, 2, 5, and 6. In brain slices, whole-cell recordings revealed long latency responses to stimulation in V2L that could modulate responses to subsequent white matter (WM) stimuli at latencies of 5-20 ms. Calcium responses imaged in Au1 cell populations showed that preceding WM with V2L stimulation modulated WM responses, with both summation and suppression observed. Modulation of WM responses was most evident for near-threshold WM stimuli. These data indicate that corticocortical projections from V2 contribute to multimodal integration in primary auditory cortex.

Using touch-screen technology to assess smoking in a low-income primary care clinic: a pilot study

This pilot study examined the use of a touch-screen tablet personal computer to assess smoking and alcohol use among low-income primary care patients (N = 100) and tested cross-method consistency with a paper assessment. Data were collected in 2009. A touch-screen survey assessed smoking, alcohol use, partner smoking, and acceptability. A separate paper survey assessed smoking, partner smoking, and acceptability. The touch-screen assessment was highly acceptable and reliable. Implications and limitations are noted. Future research should explore the use of touch-screen technology for clinical endeavors requiring a quick assessment of substance use. There was no outside funding for this study.

Evaluation of inputs to rat primary auditory cortex from the suprageniculate nucleus and extrastriate visual cortex

Evidence indicates that visual stimuli influence cells in the primary auditory cortex. To evaluate potential sources of this visual input and how they enter into the circuitry of the auditory cortex, we examined axonal terminations in the primary auditory cortex from nonprimary extrastriate visual cortex (V2M, V2L) and from the multimodal thalamic suprageniculate nucleus (SG). Gross biocytin/biotinylated dextran amine (BDA) injections into the SG or extrastriate cortex labeled inputs terminating primarily in superficial and deep layers. SG projects primarily to layers I, V, and VI while V2M and V2L project primarily to layers I and VI, with V2L also targeting layers II/III. Layer I inputs differ in that SG terminals are concentrated superficially, V2L are deeper, and V2M are equally distributed throughout. Individual axonal reconstructions document that single axons can 1) innervate multiple layers; 2) run considerable distances in layer I; and 3) run preferentially in the dorsoventral direction similar to isofrequency axes. At the electron microscopic level, SG and V2M terminals 1) are the same size regardless of layer; 2) are non-gamma-aminobutyric acid (GABA)ergic; 3) are smaller than ventral medial geniculate terminals synapsing in layer IV; 4) make asymmetric synapses onto dendrites/spines that 5) are non-GABAergic and 6) are slightly larger in layer I. Thus, both areas provide a substantial feedback-like input with differences that may indicate potentially different roles.

Examination of thermophilic methane-producing digesters by analysis of bacterial lipids

Thermophilic methane-producing digesters were examined by the analysis of lipids to determine the microbial biomass, community structure, and nutritional status of the microbes within the digesters. The digesters received a daily feedstock of cattle feed and Bermuda grass, with some digesters receiving additional supplements of propionate, butyrate, or nitrate. Microbial biomass, measured as total extractable lipid phosphate, was decreased in slurries from digesters receiving continuous addition of the fermentation intermediates propionate or butyrate as compared with slurries from control digesters receiving the feedstock alone. In slurries from digesters that received continuous addition of nitrate, the microbial biomass was higher than in the slurries from control digesters. The control digesters had ca. 2.5 x 10 bacteria per g (dry weight) as determined from total extractable lipid phosphate. Shifts in microbial community structure were observed by analysis of ester-linked phospholipid fatty acids. Statistical analysis of the patterns of phospholipid fatty acids indicated that the digesters receiving different supplements could be distinguished from the control digester and from each other. Poly-beta-hydroxybutyric acid, an indicator of metabolic stress, was detected in slurries from all the digesters. Slurries from the nitrate-amended digester had the highest concentration of poly-beta-hydroxybutyric acid, whereas slurries from the propionate-amended digester had the lowest concentration. These chemical analyses offer a quantitative means to correlate shifts in microbial biomass, community structure, and nutritional status in complex fermentation systems to the production of a specific end product.

Isolation and Characterization of Methanomicrobium paynteri sp. nov., a Mesophilic Methanogen Isolated from Marine Sediments

A new mesophilic methanogenic bacterial species isolated from marine sediments collected in the Cayman Islands is described. Cells are small rods occuring singly without filaments, are not motile, and do not possess flagella. Colonies are semitransparent and off-white in color. After 2 weeks of incubation at 37 degrees C colonies are 1 to 2 mm in size, circular, and have entire edges. Only hydrogen-carbon dioxide is a substrate for growth and methane formation. Cells can tolerate a variety of organic secondary buffers (bicarbonate-CO(2) being the primary buffer). Cells do not require yeast extract or Trypticase, but do require acetate, for growth. The optimum growth temperature is 40 degrees C. The optimum sodium concentration is 0.15 M. The optimum pH for growth is 7.0. The minimum generation time is 4.8 h. The DNA base composition is 44.9 mol% guanine plus cytosine. The name Methanomicrobium paynteri is proposed in honor of M. J. B. Paynter. The type strain is G-2000 (=ATCC 33997, =DSM 2545).

Isolation of a Butyrate-Utilizing Bacterium in Coculture with Methanobacterium thermoautotrophicum from a Thermophilic Digester

Sludge from a thermophilic, 55 degrees C digester produced methane without a lag period when enriched with butyrate. The sludge was found by most-probable-number enumeration to have ca. 5 x 10 butyrate-utilizing bacteria per ml. A thermophilic butyrate-utilizing bacterium was isolated in coculture with Methanobacterium thermoautotrophicum. This bacterium was a gram-negative, slightly curved rod, occurred singly, was nonmotile, and did not appear to produce spores. When this coculture was incubated with Methanospirillum hungatei at 37 degrees C, the quantity of methane produced was less than 5% of the methane produced when the coculture was incubated at 55 degrees C, the routine incubation temperature. The coculture required clarified digester fluid. The addition of yeast extract to medium containing 5% clarified digester fluid stimulated methane production when a Methanosarcina sp. was present. Hydrogen in the gas phase prevented butyrate utilization. However, when the hydrogen was removed, butyrate utilization began. Penicillin G and d-cycloserine caused the complete inhibition of butyrate utilization by the coculture. The ability of various ecosystems to convert butyrate to methane was studied. Marine sediments enriched with butyrate required a 2-week incubation period before methanogenesis began. Hypersaline sediments did not produce methane after 3 months when enriched with butyrate.

Isolation and Characterization of Xylan-Degrading Strains of Butyrivibrio fibrisolvens from a Napier Grass-Fed Anaerobic Digester

Six new xylanolytic bacterial strains have been isolated from a Napier grass-fed anaerobic digester. These strains were identified as Butyrivibrio fibrisolvens and were similar in many respects to ruminal isolates described previously. The new isolates exhibited a high degree of DNA homology with several ruminal strains of B. fibrisolvens. Xylan or xylose was required to induce the production of enzymes for xylan degradation, xylanase and xylosidase. Production of these enzymes was repressed in the presence of glucose. Xylanase activity was predominantly extracellular, while that of xylosidases was cell associated. The new isolates of B. fibrisolvens grew well in defined medium containing xylan as the sole carbon source and did not produce obvious slime or capsular layers. These strains may be useful for future genetic investigations.

Quantitative influences of butyrate or propionate on thermophilic production of methane from biomass

Sodium butyrate and sodium propionate were continuously infused into separate 4-liter thermophilic digesters. These digesters were operated at 55 degrees C, had a retention time of 20 days, and had a pH of 7.8. Infusion rates were started at 10 mM day and were increased incrementally when new stable external organic acid pool sizes and new stable gas production rates were observed. Stable conditions were obtained in both digesters at an infusion rate of 15 mM day, with methanogenesis elevated over that of control digesters. Calculations based on expected CH(4) at this infusion rate and measured CH(4) production in the treated and control digesters, however, showed an approximately 25% inhibition of methanogenesis in both digesters. A digester infused with sodium chloride showed little or no inhibition at this infusion rate, but was totally inhibited when its infusion rate was increased to 20 mM day, and cumulative added NaCl reached 0.38 M. The butyrate and propionate-amended digesters tolerated addition rates of 20 mM day, but both failed when they were increased to 25 mM day. These results indicate that the thermophilic digesters could function stably at higher external pool sizes of butyrate or propionate than routinely observed.

Isolation and characterization of a halophilic methanogen from great salt lake

A halophilic methanogenic microorganism isolated from sediments collected from the southern arm of Great Salt Lake, Utah, is described. Cells were irregular, nonmotile cocci approximately 1.0 mum in diameter and stained gram negative. Colonies from anaerobic plates and roll tubes were foamy, circular, and cream-yellow. Methanol, methylamine, dimethylamine, and trimethylamine supported growth and methanogenesis. Hydrogen-carbon dioxide, formate, and acetate were not utilized. Sodium and magnesium were required for growth; the optimum NaCl concentration ranged between 1.0 and 2.0 M, with the minimum doubling time occurring at 2.0 M. The optimum growth temperature was 35 degrees C, with maximum growth rate occurring at pH 7.5. The DNA base composition was 48.5 mol% guanine + cytosine. SLP is the type strain designation (= ATCC 35705).

Evidence for calcium carbonate at the Mars Phoenix landing site

Carbonates are generally products of aqueous processes and may hold important clues about the history of liquid water on the surface of Mars. Calcium carbonate (approximately 3 to 5 weight percent) has been identified in the soils around the Phoenix landing site by scanning calorimetry showing an endothermic transition beginning around 725 degrees C accompanied by evolution of carbon dioxide and by the ability of the soil to buffer pH against acid addition. Based on empirical kinetics, the amount of calcium carbonate is most consistent with formation in the past by the interaction of atmospheric carbon dioxide with liquid water films on particle surfaces.

H2O at the Phoenix landing site

The Phoenix mission investigated patterned ground and weather in the northern arctic region of Mars for 5 months starting 25 May 2008 (solar longitude between 76.5 degrees and 148 degrees ). A shallow ice table was uncovered by the robotic arm in the center and edge of a nearby polygon at depths of 5 to 18 centimeters. In late summer, snowfall and frost blanketed the surface at night; H(2)O ice and vapor constantly interacted with the soil. The soil was alkaline (pH = 7.7) and contained CaCO(3), aqueous minerals, and salts up to several weight percent in the indurated surface soil. Their formation likely required the presence of water.

The volley theory and the spherical cell puzzle

Temporal coding in the auditory nerve is strikingly transformed in the cochlear nucleus. In contrast to fibers in the auditory nerve, some neurons in the cochlear nucleus can show "picket fence" phase-locking to low-frequency pure tones: they fire a precisely timed action potential at every cycle of the stimulus. Such synchronization enhancement and entrainment is particularly prominent in neurons with the spherical and globular morphology, described by Osen [Osen KK (1969) Cytoarchitecture of the cochlear nuclei in the cat. J Comp Neurol 136:453-483]. These neurons receive large axosomatic terminals from the auditory nerve--the end bulbs and modified end bulbs of Held--and project to binaural comparator nuclei in the superior olivary complex. The most popular model to account for picket fence phase-locking is monaural coincidence detection. This mechanism is plausible for globular neurons, which receive a large number of inputs. We draw attention to the existence of enhanced phase-locking and entrainment in spherical neurons, which receive too few end-bulb inputs from the auditory nerve to make a coincidence detection of end-bulb firings a plausible mechanism of synchronization enhancement.

Cortical and collicular inputs to cells in the rat paralaminar thalamic nuclei adjacent to the medial geniculate body

The paralaminar nuclei, including the medial division of the medial geniculate nucleus, surround the auditory thalamus medially and ventrally. This multimodal area receives convergent inputs from auditory, visual, and somatosensory structures and sends divergent outputs to cortical layer 1, amygdala, basal ganglia, and elsewhere. Studies implicate this region in the modulation of cortical 40-Hz oscillations, cortical information binding, and the conditioned fear response. We recently showed that the basic anatomy and intrinsic physiology of paralaminar cells are unlike that of neurons elsewhere in sensory thalamus. Here we evaluate the synaptic inputs to paralaminar cells from the inferior and superior colliculi and the cortex. Combined physiological and anatomical evidence indicates that paralaminar cells receive both excitatory and inhibitory inputs from both colliculi and excitatory cortical inputs. Excitatory inputs from all three sources typically generate small summating EPSPs composed of AMPA and NMDA components and terminate primarily on smaller dendrites and occasionally on dendritic spines. The cortical input shows strong paired-pulse facilitation (PPF), whereas both collicular inputs show weak PPF or paired-pulse depression (PPD). EPSPs of cells with no low-threshold calcium conductance do not evoke a burst response when the cell is hyperpolarized. Longer-latency EPSPs were seen and our evidence indicates that these arise from axon collateral inputs of other synaptically activated paralaminar cells. The inhibitory collicular inputs are GABAergic, activate GABA(A) receptors, and terminate on dendrites. Their activation can greatly alter EPSP-generated spike number and timing.

STS markers for the wheat yellow rust resistance geneYr5suggest a NBS–LRR-type resistance gene cluster

Two sequence-tagged site (STS) markers for the wheat yellow rust resistance (R) gene Yr5 have been derived through the identification and characterization of linked amplified fragment length polymorphisms (AFLPs). The sequences of the 2 AFLP markers partially overlap with one another, but belong to discrete loci: S19M93-140 completely cosegregates with Yr5, whereas S23M41-310 maps at a distance of 0.7 cM. The DNA sequence of S23M41-310 shows significant homology with the 3′ end of nucleotide-binding site (NBS) - leucine-rich repeat (LRR) - type R-genes, in particular with orthologues of the rice bacterial blight R-gene Xa-I. The distinct genetic location of the 2 AFLP loci suggests that Yr5 falls within an R-gene cluster. Because neither sequence forms part of a detectable transcription product, we propose that the Yr5 R-gene cluster includes R-gene analogues and pseudogenes. A Yr5 flanking simple sequence repeat (SSR) marker has also been identified, which allows Yr5 to be effectively incorporated, along with other R-genes for yellow rust, into elite wheat genetic backgrounds, through marker-assisted selection.

Unique combination of anatomy and physiology in cells of the rat paralaminar thalamic nuclei adjacent to the medial geniculate body

The medial geniculate body (MGB) has three major subdivisions, ventral (MGV), dorsal (MGD), and medial (MGM). MGM is linked with paralaminar nuclei that are situated medial and ventral to MGV/MGD. Paralaminar nuclei have unique inputs and outputs compared with MGV and MGD and have been linked to circuitry underlying some important functional roles. We recorded intracellularly from cells in the paralaminar nuclei in vitro. We found that they possess an unusual combination of anatomical and physiological features compared with those reported for "standard" thalamic neurons seen in the MGV/MGD and elsewhere in the thalamus. Compared with MGV/MGD neurons, anatomically, 1) paralaminar cell dendrites can be long, branch sparingly, and encompass a much larger area; 2) their dendrites may be smooth but can have well defined spines; and 3) their axons can have collaterals that branch locally within the same or nearby paralaminar nuclei. When compared with MGV/MGD neurons, physiologically, 1) their spikes are larger in amplitude and can be shorter in duration; 2) their spikes can have dual afterhyperpolarizations with fast and slow components; and 3) they can have a reduction or complete absence of the low-threshold, voltage-sensitive calcium conductance that reduces or eliminates the voltage-dependent burst response. We also recorded from cells in the parafascicular nucleus, a nucleus of the posterior intralaminar nuclear group, because they have unusual anatomical features that are similar to those of some of our paralaminar cells. As with the labeled paralaminar cells, parafascicular cells had physiological features distinguishing them from typical thalamic neurons.

Acoustic stria: anatomy of physiologically characterized cells and their axonal projection patterns

The mammalian cochlear nucleus (CN) has been a model structure to study the relationship between physiological and morphological cell classes. Several issues remain, in particular with regard to the projection patterns and physiology of neurons that exit the CN dorsally via the dorsal (DAS), intermediate (IAS), and commissural stria. We studied these neurons physiologically and anatomically using the intra-axonal labeling method. Multipolar cells with onset chopper (O(C)) responses innervated the ipsilateral ventral and dorsal CN before exiting the CN via the commissural stria. Upon reaching the midline they turned caudally to innervate the opposite CN. No collaterals were seen innervating any olivary complex nuclei. Octopus cells typically showed onset responses with little or no sustained activity. The main axon used the IAS and followed one of two routes occasionally giving off olivary complex collaterals on their way to the contralateral ventral nucleus of the lateral lemniscus (VNLL). Here they can have elaborate terminal arbors that surround VNLL cells. Fusiform and giant cells have overlapping but not identical physiology. Fusiform but not giant cells typically show pauser or buildup responses. Axons of both cells exit via the DAS and take the same course to reach the contralateral IC without giving off any collaterals en route.

Atmospheric imaging results from the Mars exploration rovers: Spirit and Opportunity

A visible atmospheric optical depth of 0.9 was measured by the Spirit rover at Gusev crater and by the Opportunity rover at Meridiani Planum. Optical depth decreased by about 0.6 to 0.7% per sol through both 90-sol primary missions. The vertical distribution of atmospheric dust at Gusev crater was consistent with uniform mixing, with a measured scale height of 11.56 +/- 0.62 kilometers. The dust's cross section weighted mean radius was 1.47 +/- 0.21 micrometers (mm) at Gusev and 1.52 +/- 0.18 mm at Meridiani. Comparison of visible optical depths with 9-mm optical depths shows a visible-to-infrared optical depth ratio of 2.0 +/- 0.2 for comparison with previous monitoring of infrared optical depths.

Evidence from Opportunity's Microscopic Imager for water on Meridiani Planum

The Microscopic Imager on the Opportunity rover analyzed textures of soils and rocks at Meridiani Planum at a scale of 31 micrometers per pixel. The uppermost millimeter of some soils is weakly cemented, whereas other soils show little evidence of cohesion. Rock outcrops are laminated on a millimeter scale; image mosaics of cross-stratification suggest that some sediments were deposited by flowing water. Vugs in some outcrop faces are probably molds formed by dissolution of relatively soluble minerals during diagenesis. Microscopic images support the hypothesis that hematite-rich spherules observed in outcrops and soils also formed diagenetically as concretions.

Textures of the soils and rocks at Gusev Crater from Spirit's Microscopic Imager

The Microscopic Imager on the Spirit rover analyzed the textures of the soil and rocks at Gusev crater on Mars at a resolution of 100 micrometers. Weakly bound agglomerates of dust are present in the soil near the Columbia Memorial Station. Some of the brushed or abraded rock surfaces show igneous textures and evidence for alteration rinds, coatings, and veins consistent with secondary mineralization. The rock textures are consistent with a volcanic origin and subsequent alteration and/or weathering by impact events, wind, and possibly water.

The genetics of non-host disease resistance in wheat to barley yellow rust

Non-host resistance is investigated as a potential source of durable resistance. However, the genetics of non-host resistance between closely related plant species and their corresponding pathogens would indicate that in these interactions, non-host resistance primarily involves major genes that operate on a gene-for-gene principal similar to that seen in host resistance. Wheat is a non-host of the barley-attacking form of the fungus responsible for yellow rust, i.e. Puccinia striiformis f. sp. hordei. While P. striiformis f. sp. hordei is generally unable to infect wheat, a partial susceptibility was exhibited by the wheat variety Chinese 166. Consequently, in the cross Lemhi x Chinese 166 two major QTLs for resistance to P. striiformis f. sp. hordei were identified: one on chromosome 1D and a second on 2B. These two QTLs accounted for 43.5% and 33.2% of the phenotypic variance for resistance to barley yellow rust, respectively. In addition, two QTLs of smaller effect were also identified: one on chromosome 5A, contributing 5.1% of the variance and a second on chromosome 6A, contributing 10.9% to the phenotype. The QTL on 6A was derived from the susceptible variety, Chinese 166. In all cases the resistance towards P. striiformis f. sp. hordei was associated with a visual chlorosis/necrosis response typical of race-specific host resistance.

A genetic analysis of adult plant resistance to stripe rust in the wheat cultivar Kariega

The wheat cultivar Kariega expresses complete adult plant resistance to stripe rust in South Africa. The aim of this investigation was to determine the extent and nature of variability in stripe rust resistance in a population of 150 doubled haploid lines generated from a cross between Kariega and the susceptible cultivar Avocet S. Analysis of field data for adult plant stripe rust resistance identified two major QTLs and two minor QTLs in the resistant cultivar Kariega. The two major QTLs were located on chromosomes 7D ( QYr.sgi-7D) and 2B ( QYr.sgi-2B.1), contributing 29% and 30% to the phenotypic variance, respectively. QYr.sgi-2B.1 is primarily associated with a chlorotic and/or necrotic response, unlike QYr.sgi-7D, which is believed to be the adult plant resistance gene Yr18. These two QTLs for adult plant resistance in Kariega appear to represent different forms of resistance, where QYr.sgi-7D may represent potentially more durable resistance than QYr.sgi-2B.1. Mixture model analysis of the field leaf infection scores suggested a genetic model involving two independent genes combining in a classical, epistatic manner. The results of the QTL analysis demonstrate its higher resolution power compared to the mixture model analysis by detecting the presence of minor QTLs.

An economical bioreactor for evaluating biogas potential of particulate biomass

An economical bioreactor designed for evaluating the biogas potential of particulate biomass is described. The bioreactor uses a simple stirring apparatus, called the Bordeaux stirrer, to enable gas-tight mixing of fermentation cultures. The apparatus consists of a low-rpm motor connected to a bent steel stir rod, which is placed in a length of flexible plastic tubing inserted through a rubber stopper in a gas-tight manner. This stirrer is suitable for providing intermittent or continuous mixing in bench-scale anaerobic cultures containing particulate biomass. The reactor system may be operated as a batch-fed or semi-continuously fed digester. This communication documents the advantages of the stirring apparatus, describes the details of reactor fabrication and operation, and outlines the type of experimental work for which the bioreactor is suitable.

Distribution and kinetic properties of GABAergic inputs to layer V pyramidal cells in rat auditory cortex

Neocortical layer V is distinguished by both its pyramidal cells and its varied cortical and extracortical projections. Several studies suggest that the layer V pyramidal cell types, intrinsically bursting (IB) and regular spiking (RS) cells, differ both in the circuits in which they participate and in their inhibitory inputs. We quantified differences in inhibitory inputs to RS and IB cells using whole-cell voltage clamp techniques in the auditory cortex. We recorded miniature inhibitory postsynaptic currents (mIPSCs) and spontaneous IPSCs to gain kinetic, amplitude, and frequency information about GABAergic synapses. We then used focal sucrose applications to elicit mIPSC rate increases at the soma or dendrites of both cell types. We also electrically stimulated the axons giving rise to inhibitory synaptic inputs to measure minimally evoked IPSCs occurring at the soma or apical dendrites. We found that spontaneous and evoked IPSCs recorded from the auditory cortex have faster rise and decay kinetics when directly compared with those of the same layer V cells in other sensory cortical areas. We also found that mIPSCs observed in auditory IB and RS cells are different from one another. RS cell mIPSCs are larger and have faster rises and decays than IB cell mIPSCs, but IB cell mIPSCs occur more frequently. Focal sucrose application showed that most IB cell mIPSCs originate in the dendrites and are subject to dendritic filtering while most RS cell mIPSCs originate at the soma and are not filtered. These findings suggest that, first, IB and RS cells process their inputs in fundamentally different ways and, second, auditory cortical RS and IB cells may have specializations that allow them to process inhibitory inputs faster.

Mutations in wheat showing altered field resistance to yellow and brown rust

Intensive screening of a small population of mutagenised wheat lines revealed a large number of lines with altered resistance to both yellow and brown rust. The parental cultivar Guardian has an intermediate level of adult plant resistance to this disease; mutants were therefore isolated that showed either enhanced resistance or enhanced susceptibility to yellow rust. Seven lines were identified that gave an altered yellow rust disease phenotype as adult plants under both field and greenhouse conditions. Simultaneous field testing for brown rust infection identified two of these lines as having increased resistance to brown rust.

Effects of paired-pulse and repetitive stimulation on neurons in the rat medial geniculate body

Many behaviorally relevant sounds, including language, are composed of brief, rapid, repetitive acoustic features. Recent studies suggest that abnormalities in producing and understanding spoken language are correlated with abnormal neural responsiveness to such auditory stimuli at higher auditory levels [Tallal et al., Science 271 (1996) 81-84; Wright et al., Nature 387 (1997) 176-178; Nagarajan et al., Proc. Natl. Acad. Sci. USA 96 (1999) 6483-6488] and with abnormal anatomical features in the auditory thalamus [Galaburda et al., Proc. Natl. Acad. Sci. USA 91 (1994) 8010-8013]. To begin to understand potential mechanisms for normal and abnormal transfer of sensory information to the cortex, we recorded the intracellular responses of medial geniculate body thalamocortical neurons in a rat brain slice preparation. Inferior colliculus or corticothalamic axons were excited by pairs or trains of electrical stimuli. Neurons receiving only excitatory collicular input had tufted dendritic morphology and displayed strong paired-pulse depression of their large, short-latency excitatory postsynaptic potentials. In contrast, geniculate neurons receiving excitatory and inhibitory collicular inputs could have stellate or tufted morphology and displayed much weaker depression or even paired-pulse facilitation of their smaller, longer-latency excitatory postsynaptic potentials. Depression was not blocked by ionotropic glutamate, GABA(A) or GABA(B) receptor antagonists. Facilitation was unaffected by GABA(A) receptor antagonists but was diminished by N-methyl-D-aspartate (NMDA) receptor blockade. Similar stimulation of the corticothalamic input always elicited paired-pulse facilitation. The NMDA-independent facilitation of the second cortical excitatory postsynaptic potential lasted longer and was more pronounced than that seen for the excitatory collicular inputs. Paired-pulse stimulation of isolated collicular inhibitory postsynaptic potentials generated little change in the second GABA(A) potential amplitude measured from the resting potential, but the GABA(B) amplitude was sensitive to the interstimulus interval. Train stimuli applied to collicular or cortical inputs generated intra-train responses that were often predicted by their paired-pulse behavior. Long-lasting responses following train stimulation of the collicular inputs were uncommon. In contrast, corticothalamic inputs often generated long-lasting depolarizing responses that were dependent on activation of a metabotropic glutamate receptor. Our results demonstrate that during repetitive afferent firing there are input-specific mechanisms controlling synaptic strength and membrane potential over short and long time scales. Furthermore, they suggest that there may be two classes of excitatory collicular input to medial geniculate neurons and a single class of small-terminal corticothalamic inputs, each of which has distinct features.

Prostatic stem cells

Multipotent cells within the epithelial compartment, together with phenotypically 'plastic' mesenchyma cells (stromal stem cells), provide a repository of protected genetic information from which the structure, stability and functionality of the prostate gland can be maintained. However, mere preservation of cells in a non-dividing state is insufficient to provide the necessary reservoir of information from which the structure and function of the prostate gland can be retained or recreated. Rather, there is a constant dynamic interaction, at the level of information exchange, between stem cells (whether epithelial or mesenchymal) and their surrounding environment (both humoral and physical). Thus, with respect to epithelial stem cells, these reside within environmental 'niches' which allow their controlled and limited proliferation while preserving genomic integrity. Similar 'mesenchymal niches' are also predicted to occur, although not yet identified, thus providing the multipotent source from which the full spectrum of stromal phenotypes might be regenerated. Recent data from studies of the haematopoietic and hepato-biliary systems indicate that the potential scope of stem cells far exceeds the immediate phenotypic complement of those tissues within which they originate, being dependent upon their precise environment as well as their genomic integrity.

Provision of MRI can significantly reduce CT collective dose

The purpose of this study was to investigate the proportion of patients currently being investigated by CT that could be investigated by MRI with a potential reduction in exposure to ionizing radiation. The health detriment arising from the radiation dose associated with CT has been quantified in terms of the number of likely cases of serious health effects. The results show that a significant saving in the collective radiation dose is possible, with an associated detriment of between 0.23 and 0.33 cases of cancer or severe hereditary effects averted in one imaging department every year. In selecting the balance of provision of MRI and CT facilities, the health detriment associated with the radiation dose from CT should be considered.

Fundamental differences between the thalamocortical recipient layers of the cat auditory and visual cortices

In visual and somatosensory cortices of several species, spiny stellate cells in layer 4 are the first elements in signal processing where thalamic information is integrated and emergent receptive field properties are generated and sent on to more superficial cortical layers. In vivo and in vitro experiments have provided important information about how the anatomy and physiology of these cells and this layer fit into the functional cortical circuitry. No such data exist for the auditory cortex but are requisite if we are to understand whether ideas about information processing in one sensory cortical area can be generalized to another. Accordingly, we used in vitro slices from which to record and labeled cells in the middle layers of the cat auditory and visual cortices to compare basic anatomical and physiological features of cells recovered in similar layers using the same methods. Our results demonstrate a striking difference in a basic characteristic of two primary sensory cortical areas. In the visual cortex, spiny stellate cells predominate, receive short-latency synaptic inputs, and project to supergranular layers. No such spiny stellate population is encountered in the middle layers of the auditory cortex. Spiny cells that are not stellate or pyramidal are occasionally encountered but, as a group, do not display consistent anatomical or physiological features that might allow them to function as auditory cortical versions of the visual spiny stellates. Rather, pyramidal cells in the lower half of layer 3 and layer 4 appear to have assumed this role.

Human cutaneous fatty acid-binding protein induces metastasis by up-regulating the expression of vascular endothelial growth factor gene in rat Rama 37 model cells

Human cutaneous fatty acid-binding protein (C-FABP) gene is capable of inducing the metastatic phenotype when overexpressed in nonmetastatic rat Rama 37 cells. However, the mechanism of how it induces metastasis is not clear. Northern and slot blot analyses revealed that expression of the endogenous vascular endothelial growth factor (VEGF) gene was increased by 3.8-5.2-fold in the C-FABP-transfected cells (pSV-CFABP-R37) and in their metastatic sublines (e.g., Met-1) when compared with that in the nonmetastatic control transfectant pSV-R37 cells generated by transfection of only plasmid DNA. Higher levels of VEGF immunoreactive protein were also secreted from the malignant C-FABP-expressing cells. Reverse transcription-PCR detected two VEGF transcript isoforms, VEGF(164) and VEGF(188), in both the nonmetastatic control transfectant pSV-R37 cells and the malignant metastatic Met-1 cells. Chick chorioallantoic membrane assays showed that the conditioned medium of the control pSV-R37 cells possessed only very weak angiogenic activity, whereas conditioned media from the metastatic C-FABP transfectants and their sublines were strongly angiogenic and could be inhibited by antibodies to VEGF. Transfection of VEGF(164) cDNA in an expression vector into nonmetastatic Rama 37 cells produced a cell clone (R37-VEGF-2) that expressed high levels of VEGF. Inoculation of R37-VEGF-2 cells into syngeneic Wistar Furth rats produced metastases in a significant number (Fisher's exact test, P < 0.01) of animals (18 of 31 animals), whereas the control, vector alone-transfected R37-PSV cells produced no metastases (0 of 30 animals). Immunocytochemical methods demonstrated a strong positive staining for VEGF and an increased microvessel density in the primary tumors produced from PSV-VEGF-2 cells in comparison with tumors produced from control transfectants. Immunocytochemical staining for factor VIII detected a 3.5-fold increase in microvessel density of the primary tumors produced by PSV-VEGF-2 cells when compared with that of the primary tumors developed from the control pSV-R37 cells. Therefore, we suggest that overexpression of the C-FABP gene in the original transfectants induces metastasis through up-regulation of expression of the VEGF gene in this rat Rama 37 model system, and thus VEGF may play a crucial role in this particular metastatic cascade.