Two categories of c/c ratios for higher plants

(13)C/(12)C ratios have been determined for plant tissue from 104 species representing 60 families. Higher plants fall into two categories, those with low delta(PDBI) (13)C values (-24 to -34 per thousand) and those with high delta (13)C values (-6 to -19 per thousand). Algae have delta (13)C values of -12 to -23 per thousand. Photosynthetic fractionation leading to such values is discussed.

Deployment risk and resilience inventory-2 (DRRI-2): an updated tool for assessing psychosocial risk and resilience factors among service members and veterans

The Deployment Risk and Resilience Inventory (DRRI) is a widely used instrument for assessing deployment-related risk and resilience factors among war veterans. A revision of this instrument was recently undertaken to enhance the DRRI’s applicability across a variety of deployment-related circumstances and military subgroups. The resulting suite of 17 distinct DRRI-2 scales is the product of a multiyear psychometric endeavor that involved (a) focus groups with Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans to inform an assessment of the content validity of original DRRI measures, (b) examination of item and scale characteristics of revised scales in a national sample of 469 OEF/OIF veterans, and (c) administration of refined scales to a second national sample of 1,046 OEF/OIF veterans to confirm their psychometric quality. Both classical test theory and item response theory analytical strategies were applied to inform major revisions, which included updating the coverage of warfare-related stressors, expanding the assessment of family factors throughout the deployment cycle, and shortening scales. Finalized DRRI-2 scales demonstrated strong internal consistency reliability and criterion-related validity. The DRRI-2 can be applied to examine the role that psychosocial factors play in post deployment health and inform interventions aimed at reducing risk and enhancing resilience among war veterans.

Pseudorabies virus expressing enhanced green fluorescent protein: A tool for in vitro electrophysiological analysis of transsynaptically labeled neurons in identified central nervous system circuits

Physiological properties of central nervous system neurons infected with a pseudorabies virus were examined in vitro by using whole-cell patch-clamp techniques. A strain of pseudorabies virus (PRV 152) isogenic with the Bartha strain of PRV was constructed to express an enhanced green fluorescent protein (EGFP) from the human cytomegalovirus immediate early promoter. Unilateral PRV 152 injections into the vitreous body of the hamster eye transsynaptically infected a restricted set of retinorecipient neurons including neurons in the hypothalamic suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) of the thalamus. Retinorecipient SCN neurons were identified in tissue slices prepared for in vitro electrophysiological analysis by their expression of EGFP. At longer postinjection times, retinal ganglion cells in the contralateral eye also expressed EGFP, becoming infected after transsynaptic uptake and retrograde transport from infected retinorecipient neurons. Retinal ganglion cells that expressed EGFP were easily identified in retinal whole mounts viewed under epifluorescence. Whole-cell patch-clamp recordings revealed that the physiological properties of PRV 152-infected SCN neurons were within the range of properties observed in noninfected SCN neurons. Physiological properties of retinal ganglion cells also appeared normal. The results suggest that PRV 152 is a powerful tool for the transsynaptic labeling of neurons in defined central nervous system circuits that allows neurons to be identified in vitro by their expression of EGFP, analyzed electrophysiologically, and described in morphological detail.

Electrophysiological characteristics of immunochemically identified rat oxytocin and vasopressin neurones in vitro

1. Intracellular recordings were made from supraoptic neurones in vitro from hypothalamic explants prepared from adult male rats. Neurones were injected with biotinylated markers, and of thirty-nine labelled neurones, nineteen were identified immunocytochemically as containing oxytocin-neurophysin and twenty as containing vasopressin-neurophysin. 2. Vasopressin and oxytocin neurones did not differ in their resting membrane potential, input resistance, membrane time constant, action potential height from threshold, action potential width at half-amplitude, and spike hyperpolarizing after-potential amplitude. Both cell types exhibited spike broadening during brief, evoked spike trains (6-8 spikes), but the degree of broadening was slightly greater for vasopressin neurones. When hyperpolarized below -75 mV, all but one neurone exhibited a transient outward rectification to depolarizing pulses, which delayed the occurrence of the first spike. 3. Both cell types exhibited a long after-hyperpolarizing potential (AHP) following brief spike trains evoked either with a square wave pulse or using 5 ms pulses in a train. There were no significant differences between cell types in the size of the AHP evoked with nine spikes, or in the time constant of its decay. The maximal AHP evoked by a 180 ms pulse was elicited by an average of twelve to thirteen spikes, and neither the size of this maximal AHP nor its time constant of decay were different for the two cell types. 4. In most oxytocin and vasopressin neurones the AHP, and concomitantly spike frequency adaptation, were markedly reduced by the bee venom apamin and by d-tubocurarine, known blockers of a Ca(2+)-mediated K+ conductance. However, a minority of neurones, of both cell types, were relatively resistant to both agents. 5. In untreated neurones, 55% of vasopressin neurones and 32% of oxytocin neurones exhibited a depolarizing after-potential (DAP) after individual spikes or, more commonly, after brief trains of spikes evoked with current pulses. For each neurone with a DAP, bursts of spikes could be evoked if the membrane potential was sufficiently depolarized such that the DAP reached spike threshold. In four out of five vasopressin neurones a DAP became evident only after pharmacological blockade of the AHP, whereas in six oxytocin neurones tested no such masking was found. 6. The firing patterns of neurones were examined at rest and after varying the membrane potential with continuous current injection. No identifying pattern was strictly associated with either cell type, and a substantial number of neurones were silent at rest.(ABSTRACT TRUNCATED AT 400 WORDS)

Comorbidity of partial and subthreshold ptsd among men and women with eating disorders in the national comorbidity survey-replication study

OBJECTIVE

The comorbidity of posttraumatic stress disorder (PTSD) and eating disorders (EDs) is high among women but has been understudied in men. Little is known about the association between partial or subthreshold PTSD and EDs among women or men.

METHOD

This study included PTSD and ED data from male (n = 2,382) and female (n = 3,310) National Comorbidity Survey-Replication study participants.

RESULTS

The vast majority of women and men with anorexia nervosa, bulimia nervosa (BN), and binge eating disorder (BED) reported a history of interpersonal trauma. Rates of PTSD were significantly higher among women and men with BN and BED. Subthreshold PTSD was more prevalent than threshold PTSD among women with BN and women and men with BED.

DISCUSSION

Interpersonal forms of trauma, PTSD, and subthreshold/partial PTSD, were prevalent among men and women with EDs. Findings highlight the importance of assessing for trauma and PTSD in ED patients.

Exposure to Interpersonal Violence and Its Associations With Psychiatric Morbidity in a U.S. National Sample: A Gender Comparison

OBJECTIVES

We examine gender differences in population rates of various types of interpersonal violence in a U.S. national sample and investigate gender as a moderator of the associations between interpersonal violence and lifetime mental disorders and suicide attempts.

METHODS

Data were drawn from the National Comorbidity Survey-Replication study; 5,692 women and men completed interviews assessing lifetime exposure to nine types of interpersonal violence, Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) mental health diagnoses, and suicide attempts.

RESULTS

Approximately 46% of women and 42% of men reported one or more types of interpersonal violence. Women were more likely to experience kidnapping, physical assault by an intimate partner, rape, sexual assault, and stalking, whereas men were more likely to experience mugging or physical assault by someone other than parents or an intimate partner. Interpersonal violence was associated with risk for many mental disorders and attempted suicide. Although women were at higher risk for several forms of interpersonal violence, the impact of interpersonal violence on mental health outcomes did not vary by gender.

CONCLUSIONS

It is clearly important to identify and provide mental health treatment to women after interpersonal violence exposure. Findings also underscore the need for prevention and intervention efforts for women and men, including routine screening for interpersonal violence by health care providers and appropriate treatment to address mental health conditions.

A pilot study of a randomized controlled trial of yoga as an intervention for PTSD symptoms in women

Posttraumatic stress disorder (PTSD) is a debilitating condition that affects approximately 10% of women in the United States. Although effective psychotherapeutic treatments for PTSD exist, clients with PTSD report additional benefits of complementary and alternative approaches such as yoga. In particular, yoga may downregulate the stress response and positively impact PTSD and comorbid depression and anxiety symptoms. We conducted a pilot study of a randomized controlled trial comparing a 12-session Kripalu-based yoga intervention with an assessment control group. Participants included 38 women with current full or subthreshold PTSD symptoms. During the intervention, yoga participants showed decreases in reexperiencing and hyperarousal symptoms. The assessment control group, however, showed decreases in reexperiencing and anxiety symptoms as well, which may be a result of the positive effect of self-monitoring on PTSD and associated symptoms. Between-groups effect sizes were small to moderate (0.08-0.31). Although more research is needed, yoga may be an effective adjunctive treatment for PTSD. Participants responded positively to the intervention, suggesting that it was tolerable for this sample. Findings underscore the need for future research investigating mechanisms by which yoga may impact mental health symptoms, gender comparisons, and the long-term effects of yoga practice.

Short- and long-term changes in CA1 network excitability after kainate treatment in rats

Neuron loss, axon sprouting, and the formation of new synaptic circuits have been hypothesized to contribute to seizures in temporal lobe epilepsy (TLE). Using the kainate-treated rat, we examined how alterations in the density of CA1 pyramidal cells and interneurons, and subsequent sprouting of CA1 pyramidal cell axons, were temporally associated with functional changes in the network properties of the CA1 area. Control rats were compared with animals during the first week after kainate treatment versus several weeks after treatment. The density of CA1 pyramidal cells and putative inhibitory neurons in stratum oriens was reduced within 8 days after kainate treatment. Axon branching of CA1 pyramidal cells was similar between controls and animals examined in the first week after kainate treatment but was increased several weeks after kainate treatment. Stimulation of afferent fibers in brain slices containing the isolated CA1 region produced graded responses in slices from controls and kainate-treated rats tested <8 days after treatment. In contrast, synchronous all-or-none bursts of spikes at low stimulus intensity (i.e., "network bursts") were only observed in the CA1 several weeks after kainate treatment. In the presence of bicuculline, the duration of evoked bursts was significantly longer in CA1 pyramidal cells weeks after kainate treatment than from controls or those examined in the first week posttreatment. Spontaneous network bursts were also observed in the isolated CA1 several weeks after kainate treatment in bicuculline-treated slices. The data suggest that the early loss of neurons directly associated with kainate-induced status epilepticus is followed by increased axon sprouting and new recurrent excitatory circuits in CA1 pyramidal cells. These changes characterize the transition from the initial acute effects of the kainate-induced insult to the eventual development of all-or-none epileptiform discharges in the CA1 area.

Vagally evoked synaptic currents in the immature rat nucleus tractus solitarii in an intact in vitro preparation

1. Whole-cell voltage-clamp recordings in an in vitro brainstem-cranial nerve explant preparation were used to assess the local circuitry activated by vagal input to nucleus tractus solitarii (NTS) neurones in immature rats. 2. All neurones that responded to vagal stimulation displayed EPSCs of relatively constant latency. Approximately 50 % of these also demonstrated variable-latency IPSCs, and approximately 31 % also displayed variable-latency EPSCs to vagal stimulation. All neurones also had spontaneous EPSCs and IPSCs. 3. Evoked and spontaneous EPSCs reversed near 0 mV and were blocked by the glutamate AMPA/kainate receptor antagonists 6,7-nitroquinoxaline-2,3-dione (DNQX) or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) at rest. Evoked EPSCs had rapid rise times (< 1 s) and decayed monoexponentially (tau = 2. 04 +/- 0.03 ms) at potentials near rest. 4. At holding potentials positive to approximately -50 mV, a slow EPSC could be evoked in the presence of DNQX or CNQX. This current peaked at holding potentials near -25 mV and was blocked by the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP5). It was therefore probably due to activation of NMDA receptors by vagal afferent fibres. 5. Fast IPSCs reversed near -70 mV and were blocked by the GABAA receptor antagonist bicuculline. In addition, bicuculline enhanced excitatory responses to vagal stimulation and increased spontaneous EPSC frequency. Antagonists to AMPA/kainate receptors reversibly blocked stimulus-associated IPSCs and also decreased the frequency of spontaneous IPSCs. 6. These findings suggest that glutamate mediates synaptic transmission from the vagus nerve to neurones in the immature NTS by acting at non-NMDA and NMDA receptors. NTS neurones may also receive glutamatergic and GABAergic synaptic input from local neurones that can be activated by vagal input and/or regulated by amino acid inputs from other brainstem neurones.1. Whole-cell voltage-clamp recordings in an in vitro brainstem-cranial nerve explant preparation were used to assess the local circuitry activated by vagal input to nucleus tractus solitarii (NTS) neurones in immature rats.

The prevalence of carbon-13 in respiratory carbon dioxide as an indicator of the types of endogenous substrate. The change from lipid to carbohydrate during the respiratory rise in potato slices

Isotope discrimination is a common feature of biosynthesis in nature, with the result that different classes of carbon compounds frequently display different (13)C/(12)C ratios. The (13)C/(12)C ratio of lipid in potato tuber tissue is considerably lower than that for starch or protein. We have collected respiratory CO(2) from potato discs in successive periods through 24 hr from the time of cutting-an interval in which the respiration rate rises 3-5-fold. The (13)C/(12)C ratio of the evolved CO(2) was determined for each period, and compared with the (13)C/(12)C ratios of the major tissue metabolites. In the first hours the carbon isotope ratio of the CO(2) matches that of lipid. With time, the ratio approaches that typical of starch or protein. An estimation has been made of the contribution of lipid and carbohydrate to the total respiration at each juncture. In connection with additional observations, it was deduced that the basal, or initial, respiration represents lipid metabolism-possibly the alpha-oxidation of long chain fatty acids-while the developed repiration represents conventional tricarboxylic acid cycle oxidation of the products of carbohydrate glycolysis. The true isotopic composition of the respiratory CO(2) may be obscured by fractionation attending the refixation of CO(2) during respiration, and by CO(2) arising from dissolved CO(2) and bicarbonate preexisting in the tuber. Means are described for coping with both pitfalls.

A Review of Studies on the System-Wide Implementation of Evidence-Based Psychotherapies for Posttraumatic Stress Disorder in the Veterans Health Administration

Since 2006, the Veterans Health Administration (VHA) has instituted policy changes and training programs to support system-wide implementation of two evidence-based psychotherapies (EBPs) for posttraumatic stress disorder (PTSD). To assess lessons learned from this unprecedented effort, we used PubMed and the PILOTS databases and networking with researchers to identify 32 reports on contextual influences on implementation or sustainment of EBPs for PTSD in VHA settings. Findings were initially organized using the exploration, planning, implementation, and sustainment framework (EPIS; Aarons et al. in Adm Policy Ment Health Health Serv Res 38:4-23, 2011). Results that could not be adequately captured within the EPIS framework, such as implementation outcomes and adopter beliefs about the innovation, were coded using constructs from the reach, effectiveness, adoption, implementation, maintenance (RE-AIM) framework (Glasgow et al. in Am J Public Health 89:1322-1327, 1999) and Consolidated Framework for Implementation Research (CFIR; Damschroder et al. in Implement Sci 4(1):50, 2009). We highlight key areas of progress in implementation, identify continuing challenges and research questions, and discuss implications for future efforts to promote EBPs in large health care systems.

Serotonergic modulation of retinal input to the mouse suprachiasmatic nucleus mediated by 5-HT1B and 5-HT7 receptors

Serotonin (5-HT) and 5-HT receptor agonists can modify the response of the mammalian suprachiasmatic nucleus (SCN) to light. It remains uncertain which 5-HT receptor subtypes mediate these effects. The effects of 5-HT receptor activation on optic nerve-mediated input to SCN neurons were examined using whole-cell patch-clamp recordings in horizontal slices of ventral hypothalamus from the male mouse. The hypothesis that 5-HT reduces the effect of retinohypothalamic tract (RHT) input to the SCN by acting at 5-HT1B receptors was tested first. As previously described in the hamster, a mixed 5-HT(1A/1B) receptor agonist, 1-[3-(trifluoromethyl)phenyl]-piperazine hydrochloride (TFMPP), reduced the amplitude of glutamatergic excitatory postsynaptic currents (EPSCs) evoked by selectively stimulating the optic nerve of wild-type mice. The agonist was negligibly effective in a 5-HT1B receptor knockout mouse, suggesting minimal contribution of 5-HT1A receptors to the TFMPP-induced reduction in the amplitude of the optic nerve-evoked EPSC. We next tested the hypothesis that 5-HT also reduces RHT input to the SCN via activation of 5-HT7 receptors. The mixed 5-HT(1A/7) receptor agonist, R(+)-8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT), reduced the evoked EPSC amplitude in both wild-type and 5-HT1B receptor knockout mice. This effect of 8-OH-DPAT was minimally attenuated by the selective 5-HT1A receptor antagonist WAY 100635 but was reversibly and significantly reduced in the presence of ritanserin, a mixed 5-HT(2/7) receptor antagonist. Taken together with the authors' previous ultrastructural studies of 5-HT1B receptors in the mouse SCN, these results indicate that in the mouse, 5-HT reduces RHT input to the SCN by acting at 5-HT1B receptors located on RHT terminals. Moreover, activation of 5-HT7 receptors in the mouse SCN, but not 5-HT1A receptors, also results in a reduction in the amplitude of the optic nerve-evoked EPSC. The findings indicate that 5-HT may modulate RHT glutamatergic input to the SCN through 2 or more 5-HT receptors. The likely mechanism of altered RHT glutamatergic input to SCN neurons is an alteration of photic effects on the SCN circadian oscillator.

Whole-cell recordings from preoptic/hypothalamic slices reveal burst firing in gonadotropin-releasing hormone neurons identified with green fluorescent protein in transgenic mice

Central control of reproduction is governed by a neuronal pulse generator that underlies the activity of hypothalamic neuroendocrine cells that secrete GnRH. Bursts and prolonged episodes of repetitive action potentials have been associated with hormone secretion in this and other neuroendocrine systems. To begin to investigate the cellular mechanisms responsible for the GnRH pulse generator, we used transgenic mice in which green fluorescent protein was genetically targeted to GnRH neurons. Whole-cell recordings were obtained from 21 GnRH neurons, visually identified in 200-microm preoptic/hypothalamic slices, to determine whether they exhibit high frequency bursts of action potentials and are electrically coupled at or near the somata. All GnRH neurons fired spontaneous action potentials, and in 15 of 21 GnRH neurons, the action potentials occurred in single bursts or episodes of repetitive bursts of high frequency spikes (9.77 +/- 0.87 Hz) lasting 3-120 sec. Extended periods of quiescence of up to 30 min preceded and followed these periods of repetitive firing. Examination of 92 GnRH neurons (including 32 neurons that were located near another green fluorescent protein-positive neuron) revealed evidence for coupling in only 1 pair of GnRH neurons. The evidence for minimal coupling between these neuroendocrine cells suggests that direct soma to soma transfer of information, through either cytoplasmic bridges or gap junctions, has a minor role in synchronization of GnRH neurons. The pattern of electrical activity observed in single GnRH neurons within slices is temporally consistent with observations of GnRH release and multiple unit electrophysiological correlates of LH release. Episodes of burst firing of individual GnRH neurons may represent a component of the GnRH pulse generator.

Selective enhancement of excitatory synaptic activity in the rat nucleus tractus solitarius by hypocretin 2

Hypocretin 2 (orexin B) is a hypothalamic neuropeptide thought to be involved in regulating energy homeostasis, autonomic function, arousal, and sensory processing. Neural circuits in the caudal nucleus tractus solitarius (NTS) integrate viscerosensory inputs, and are therefore implicated in aspects of all these functions. We tested the hypothesis that hypocretin 2 modulates fast synaptic activity in caudal NTS areas that are generally associated with visceral sensation from cardiorespiratory and gastrointestinal systems. Hypocretin 2-immunoreactive fibers were observed throughout the caudal NTS. In whole-cell recordings from neurons in acute slices, hypocretin 2 depolarized 48% and hyperpolarized 10% of caudal NTS neurons, effects that were not observed when Cs(+) was used as the primary cation carrier. Hypocretin 2 also increased the amplitude of tractus solitarius-evoked excitatory postsynaptic currents (EPSCs) in 36% of neurons and significantly enhanced the frequency of spontaneous EPSCs in most (59%) neurons. Spontaneous inhibitory postsynaptic currents (IPSCs) were relatively unaffected by the peptide. The increase in EPSC frequency persisted in the presence of tetrodotoxin, suggesting a role for the peptide in regulating glutamate release in the NTS by acting at presynaptic terminals. These data suggest that hypocretin 2 modulates excitatory, but not inhibitory, synapses in caudal NTS neurons, including viscerosensory inputs. The selective nature of the effect supports the hypothesis that hypocretin 2 plays a role in modulating autonomic sensory signaling in the NTS.

Rapid inhibition of neurons in the dorsal motor nucleus of the vagus by leptin

The peptide leptin conveys the availability of adipose energy stores to the brain. Increasing evidence implicates a significant role for extrahypothalamic sites of leptin action, including the dorsal vagal complex, a region critical for regulating visceral parasympathetic function. The hypothesis that leptin suppresses cellular activity in the dorsal motor nucleus of the vagus nerve (DMV) was tested using whole-cell patch-clamp recordings in brainstem slices. Leptin caused a rapid membrane hyperpolarization in 50% of rat DMV neurons. Leptin also hyperpolarized a subset of gastric-related neurons (62%), identified after gastric inoculation with a transneuronal retrograde viral tracer. The hyperpolarization was associated with a decrease in input resistance and cellular responsiveness and displayed characteristics consistent with an increased K+ conductance. Perfusion of tolbutamide (200 microM) reversed the leptin-induced hyperpolarization, and tolbutamide or wortmannin (10-100 nM) prevented the hyperpolarization, indicating that leptin activated an ATP-sensitive K+ channel via a phosphoinositide-3-kinase-dependent mechanism. Leptin reduced the frequency of spontaneous and miniature excitatory postsynaptic currents (EPSCs), whereas inhibitory postsynaptic currents (IPSCs) were largely unaffected. Electrical stimulation of the nucleus tractus solitarii (NTS) resulted in constant-latency EPSCs, which were decreased in amplitude by leptin. The paired-pulse ratio was increased, suggesting leptin effects involved activation of receptors presynaptic to the recorded neuron. A leptin-induced suppression of EPSCs, but not IPSCs, evoked by focal photolytic uncaging of glutamate within the NTS was also observed, supportive of leptin effects on the glutamatergic NTS projection to the DMV. Therefore, leptin directly hyperpolarized and indirectly suppressed excitatory synaptic activity to DMV neurons involved in visceral regulation, including gastric-related neurons.

Symptom exacerbations in trauma-focused treatments: Associations with treatment outcome and non-completion

Trauma-focused treatments are underutilized, partially due to clinician concerns that they will cause symptom exacerbation or dropout. We examined a sample of women undergoing Prolonged Exposure (PE), Cognitive Processing Therapy (CPT), and a version of CPT (CPT-C) without a written trauma narrative to investigate the possibility of symptom exacerbation. Participants (n = 192) were drawn from two RCT's. Participants were administered self-report measures of PTSD symptoms (i.e., the PTSD Symptom Scale or Posttraumatic Diagnostic Scale [PSS/PDS]) and the Clinician-Administered PTSD Scale. Exacerbations were defined as increases greater than 6.15 points on the PSS/PDS. A minority of participants experienced PTSD exacerbations during treatment, and there were no significant differences across treatment type (28.6% in CPT, 20.0% in PE, and 14.7% in CPT-C). Neither diagnostic nor trauma-related factors at pre-treatment predicted symptom exacerbations. Those who experienced exacerbations had higher post-treatment PSS/PDS scores and were more likely to retain a PTSD diagnosis (both small but statistically significant effects). However, even those who experienced an exacerbation experienced clinically significant improvement by end of treatment. Further, symptom exacerbations were not related to treatment non-completion. These results indicate that trauma-focused treatments are safe and effective, even for the minority of individuals who experience temporary symptom increases.

Rapid inhibition of neural excitability in the nucleus tractus solitarii by leptin: implications for ingestive behaviour

The fat-derived peptide leptin regulates cellular activity in areas of the CNS related to feeding, and application of leptin to the fourth ventricle or the nucleus tractus solitarii (NTS) inhibits food intake and weight gain. The hypothesis that leptin modulates cellular activity in the NTS was tested using whole-cell patch-clamp recordings in brainstem slices. Leptin caused a rapid membrane hyperpolarization in 58% of rat NTS neurones, including neurones receiving tractus solitarius input (i.e. viscerosensory) and those involved in regulating output to the stomach, identified after gastric inoculation with a transneuronal retrograde viral label. The hyperpolarization was accompanied by a decrease in input resistance and cellular responsiveness, reversed near the K(+) equilibrium potential, and was prevented by intracellular Cs(+). Perfusion of tolbutamide (200 microm) or wortmannin (100-200 nm) prevented the hyperpolarization, indicating activation of an ATP-sensitive K(+) channel via a PI3 kinase-dependent mechanism. Constant latency tractus solitarius-evoked EPSCs were decreased in amplitude by leptin, and the paired-pulse ratio was increased, suggesting effects on evoked EPSCs involved activation of receptors on vagal afferent terminals. Leptin reduced the frequency of spontaneous and miniature EPSCs, whereas IPSCs were largely unaffected. Leptin's effects were observed in neurones from lean, but not obese, Zucker rats. Neurones that expressed enhanced green fluorescent protein (EGFP) in a subpopulation of putative GABAergic neurones in transgenic mice did not respond to leptin, whereas unlabelled murine neurones responded similarly to rat neurones. Leptin therefore directly and rapidly suppresses activity of excitatory NTS neurones likely to be involved in viscerosensory integration and/or premotor control of the stomach.

High rates of PTSD treatment dropout: A possible red herring?

Few studies have examined symptom change among dropouts from posttraumatic stress disorder (PTSD) treatment. However, dropout is widely considered a negative event needing to be addressed. The present study investigated PTSD and depression symptom change in patients with PTSD who discontinued psychotherapy. Female civilians (n=321) diagnosed with PTSD participated in two randomized clinical trials examining PTSD treatment outcomes. Of those, 53 were identified as dropouts and included in this study. Symptom change was assessed by clinically significant change (CSC) criteria and symptom end-state criteria. Results demonstrated that considerable proportions of participants (35.85-55.56%) displayed significant improvement and/or met good end-state criteria for PTSD and depression. Results also revealed that participants who displayed symptom improvement were younger, attended more treatment sessions, were married or partnered, and had higher annual household income. Although preliminary, these findings contradict belief that treatment dropouts do not display symptom improvement.

Biogeochemistry of the stable isotopes of hydrogen and carbon in salt marsh biota

Deuterium to hydrogen ratios of 14 plant species from a salt marsh and lagoon were 55 per thousand depleted in deuterium relative to the environmental water. Carbon tetrachloride-extractable material from these plants was another 92 per thousand depleted in deuterium. This gave a fractionation factor from water to CCl(4) extract of 1.147. This over-all fractionation was remarkably constant for all species analyzed. Plants also discriminate against (13)C, particularly in the lipid fraction. Data suggest that different mechanisms for carbon fixation result in different fractionations of the carbon isotopes. Herbivore tissues reflected the isotopic ratios of plants ingested. Apparently different metabolic processes are responsible for the different degrees of fractionation observed for hydrogen and carbon isotopes.

Differences in food intake and exercise by smoking status in adolescents

BACKGROUND

Smoking, diet, and lack of exercise are the top preventable causes of death in the United States. Some 23% of high school students currently smoke and many teens do not meet Healthy People 2010 standards for healthy eating or physical activity. This study examined the relationship between smoking and the consumption of fruit, vegetables, milk/dairy products and the frequency of exercise in 10,635 Virginia youth.

METHODS

Survey data were collected from middle school (MS; n = 8022) and high school (HS; n = 2613) adolescents participating in youth tobacco prevention/cessation programs. Data were analyzed using chi-square bivariate tests and multivariate regression models.

RESULTS

Smokers were significantly less likely than nonsmokers to exercise > or = 3x week and to consume > or = 1 serving/day of vegetables or milk/dairy products. This was more evident in high school than middle school students and in females compared to males. In both HS and MS, a dose-response relationship was detected with higher level smoking associated with lower frequency of eating specified food and exercise.

CONCLUSIONS

Smoking is associated with compromised intake of healthy food and exercise. To decrease incident cases of chronic disease later in life, new tailored, innovative interventions are needed that address multiple health behaviors in youth.

Amino acid-mediated regulation of spontaneous synaptic activity patterns in the rat basolateral amygdala

1. Spontaneous postsynaptic currents (PSCs) were examined in the basolateral amygdala using whole cell patch-clamp recordings in coronal slices (400 microns) from young rats (postnatal day 6-25). In most cells, Cs+ was used in the electrode to block putative voltage-activated K(+)-currents. Both inward and outward spontaneous PSCs were examined. 2. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist, 6,7-nitroquinoxaline-2,3-dione (DNQX) blocked all inward PSCs, which reversed near 0 mV. They therefore were considered to be glutamate-mediated excitatory postsynaptic currents (EPSCs). Averaged EPSCs had a rapid 10-90% rise time (1.0 +/- 0.04 ms; mean +/- SD) and monoexponential decay (tau = 3.6 +/- 0.18 ms) at potentials negative to about -50 mV. Above this potential, a second, slower time constant (tau 1 = 41 +/- 4.5 ms at -30 mV), accounting for 10-30% of the total EPSC amplitude was resolved in 8 of 10 cells examined. The slower decay time constant was sensitive to the N-methyl-D-aspartate (NMDA)-receptor antagonist, DL-2-amino-5-phosphonovaleric acid (AP5) and therefore probably was due to activation of NMDA receptors. 3. The gamma-aminobutyric acid-A (GABAA) antagonist, bicuculline, blocked all outward PSCs, which reversed near -70 mV. They therefore were considered to be GABA-mediated inhibitory postsynaptic currents (IPSCs). Averaged IPSCs displayed rapid 10-90% rise times (1.0 +/- 0.03 ms) and monoexponential decay time constants (tau = 5.16 +/- 0.14 ms). 4. Tetrodotoxin (TTX) reduced the frequency of synaptic activity and eliminated the largest PSCs, thus reducing slightly the mean EPSC and IPSC amplitude. Most cells received bursts of spontaneous IPSCs and/or EPSCs (30-68 Hz lasting 0.5-6 s), which were also TTX sensitive. The TTX data suggest that the somata of the cells responsible for the largest PSCs and the PSC bursts were contained within the slice. 5. In addition to blocking EPSCs, DNQX blocked the bursts of IPSCs, but not all individual IPSCs. DNQX had similar effects as TTX on the bursts and frequency of the IPSCs. 6. Bicuculline enhanced spontaneous EPSC frequency (231 +/- 90%). Much of this increase was due to an increase in the bursts of EPSCs. 7. Neurons in the basolateral amygdala therefore appear to receive both excitatory (glutamatergic) and inhibitory (GABAergic) synaptic input from local neurons. The activity of the neurons responsible for these inputs are themselves largely regulated by glutamatergic and GABAergic inputs. The relevance of this local circuitry to seizures and epilepsy is discussed briefly.

Prevalence of hereditary hemochromatosis in a Massachusetts corporation: is Celtic origin a risk factor?

The prevalence of homozygous hereditary hemochromatosis (HHC) is estimated at 1:250 in Caucasian adults. Little is known about ethnic subpopulations that might be at increased risk for this disease. HLA data have suggested a Celtic origin for HHC. Screening for HHC was offered to all employees of the Massachusetts Polaroid Corporation. Participants with a transferrin saturation of >55% or >45% and an elevated serum ferritin concentration on two screenings were referred for liver biopsy. The diagnosis of HHC was based on histological criteria, quantitative hepatic iron determination, hepatic iron index, and the phlebotomy requirement for iron depletion. Participants completed a questionnaire regarding their ethnic background. Two thousand two hundred ninety-four employees were screened, and 5 cases of HHC were detected. All 5 cases involved Caucasian men, yielding a prevalence of 1:395 for the Caucasian population. Four of the 5 cases were of 100% British-Irish ancestry based on the country of origin of their grandparents. Additional analysis revealed that the majority of grandparents of all 4 individuals came from Ireland or Wales. The exact two-tailed trend test showed a significant association of HHC with Celtic background (P = .012). The estimated cost of screening per patient identified was $18,041. Polaroid Corporation has a high representation of employees of British-Irish ancestry. Our data suggest that they are at high risk for developing HHC. A significant association of HHC with Celtic ancestry was found in this subpopulation, supporting the concept of a Celtic origin for this disease.

How and when does mental illness stigma impact treatment seeking? Longitudinal examination of relationships between anticipated and internalized stigma, symptom severity, and mental health service use

Although mental illness stigma has been identified as an important barrier to mental health treatment, there is little consensus regarding how and when mental illness stigma negatively impacts treatment seeking. The relationship between mental illness stigma and treatment seeking may depend on the particular stigma mechanism under investigation, as well as an individual's symptom severity. In the present study, we examined relationships between anticipated and internalized stigma, depressive symptom severity, and mental health service use using data from a two-wave longitudinal survey study of U.S. post-9/11 veterans. Mediated and moderated relationships were tested using PROCESS. Mediation analyses revealed that higher anticipated stigma led to higher levels of internalized stigma, which was associated with decreased treatment seeking. Moderation analyses revealed that anticipated stigma was only associated with treatment seeking when depressive symptoms were severe. The central role observed for internalized stigma highlights the value of stigma reduction efforts that focus on this stigma mechanism, whereas the finding that only those individuals with more severe symptoms are vulnerable to the negative effects of anticipated stigma underscores the importance of more targeted anti-stigma interventions.

Histamine enhances the depolarizing afterpotential of immunohistochemically identified vasopressin neurons in the rat supraoptic nucleus via H1-receptor activation

Previous studies have demonstrated that histamine primarily excites unidentified neurons in the rat supraoptic nucleus. We investigated the neuromodulatory effects of histamine on immunohistochemically identified vasopressin neurons in the rat supraoptic nucleus using intracellular recording techniques from the hypothalamo-neurohypophysial explant. Exogenous application of histamine (0.1-100 microM) to vasopressinergic neurons produced a small membrane depolarization accompanied by an increase of up to 100% in the amplitude of the depolarizing afterpotential that follows current-evoked trains of action potentials. The enhancement of the depolarizing afterpotential by histamine did not depend upon the depolarization. Further, histamine enhanced the amplitude of the depolarizing afterpotential when blocking the afterhyperpolarizing potential with d-tubocurarine or apamin, and in the presence of tetrodotoxin and d-tubocurarine or apamin, indicating a postsynaptic action of histamine on the depolarizing afterpotential that is not simply a reflection of a decrease in the afterhyperpolarizing potential. These toxins also had no effect on the histamine-induced depolarization. The enhancement of the depolarizing afterpotential by histamine was mimicked by the histamine H1-receptor agonist 2-thiazolylethylamine and was reduced or blocked by the H1-receptor antagonist promethazine, but was not blocked or reduced in the presence of the histamine H2-receptor antagonist, cimetidine. In summary, these results show that the excitatory effect of histamine on immunohistochemically identified vasopressin neurons in the supraoptic nucleus is due in part to the H1-receptor-mediated enhancement of the depolarizing afterpotential independent of any change in the afterhyperpolarizing potential or membrane potential.