The (in)effectiveness of anticipatory vibrotactile cues in mitigating motion sickness.

The introduction of (fully) automated vehicles has generated a re-interest in motion sickness, given that passengers suffer much more from motion sickness compared to car drivers. A suggested solution is to improve the anticipation of passive self-motion via cues that alert passengers of changes in the upcoming motion trajectory. We already know that auditory or visual cues can mitigate motion sickness. In this study, we used anticipatory vibrotactile cues that do not interfere with the (audio)visual tasks passengers may want to perform. We wanted to investigate (1) whether anticipatory vibrotactile cues mitigate motion sickness, and (2) whether the timing of the cue is of influence. We therefore exposed participants to four sessions on a linear sled with displacements unpredictable in motion onset. In three sessions, an anticipatory cue was presented 0.33, 1, or 3 s prior to the onset of forward motion. Using a new pre-registered measure, we quantified the reduction in motion sickness across multiple sickness scores in these sessions relative to a control session. Under the chosen experimental conditions, our results did not show a significant mitigation of motion sickness by the anticipatory vibrotactile cues, irrespective of their timing. Participants yet indicated that the cues were helpful. Considering that motion sickness is influenced by the unpredictability of displacements, vibrotactile cues may mitigate sickness when motions have more (unpredictable) variability than those studied here.

Secondary data analysis investigating effects of marine omega-3 fatty acids on circulating levels of leptin and adiponectin in older adults.

BACKGROUND: Higher leptin and lower adiponectin levels have been linked to progressing systemic inflammation and diseases of aging. Among older adults with obesity and an inflammatory conditions, we quantified effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on leptin, adiponectin, and the leptin-to-adiponectin ratio (LAR). We also examined associations among adipokine and cytokine levels. METHODS: Using a randomized, double-blind, placebo-controlled design, participants (mean age 61.3 ± 2.1) received 1.5 g EPA + 1.0 g DHA (n = 14) or mineral oil (n = 18) daily. Plasma adipokine and cytokine levels were quantified by electrochemiluminescence at all study intervals. RESULTS: While no between-group differences were detected, there was a reduction in the LAR (by 23%, p=.065) between weeks 4 and 8 among the EPA+DHA group. Adiponectin levels were negatively associated with IL-1ß levels at week 4 (p=.02) and TNF-α levels at week 8 (p=.03). CONCLUSION: Potential benefits of EPA+DHA supplementation among aging populations warrant further study.

[Molecular and metabolic changes in human clear cell liver foci]. / Molekulare und metabolische Veränderungen in humanen klarzelligen Leberherden.

Activation of the AKT/mTOR and Ras/MAPK pathways and the lipogenic phenotype are evident both in human hepatocellular carcinoma and in the rat model of insulin-induced hepatocarcinogenesis in the earliest preneoplastic lesions, i.e. clear cell foci (CCF) of altered hepatocytes. These CCFs have also been described in the human liver but characterization of molecular and metabolic changes are still pending. In this study, human sporadic CCFs were investigated in a collection of human non-cirrhotic liver specimens using histology, histochemistry, immunohistochemistry, electron microscopy and molecular pathological analysis. Human CCFs occurred in approximately 33 % of non-cirrhotic livers and stored masses of glycogen in the cytoplasm, largely due to reduced activity of glucose-6-phosphatase. Hepatocytes revealed an upregulation of the AKT/mTOR and the Ras/MAPK pathways, the insulin receptor, glucose transporters and enzymes of glycolysis and de novo lipogenesis. Proliferative activity was 2-fold higher than in extrafocal tissue. The CCFs of altered hepatocytes are metabolically and proliferatively active lesions even in humans. They resemble the well-known preneoplastic lesions from experimental models in terms of morphology, glycogen storage, overexpression of protooncogenic signaling pathways and activation of the lipogenic phenotype, which are also known in human hepatocellular carcinoma. This suggests that hepatic CCFs also represent very early lesions of hepatocarcinogenesis in humans.

Family involvement with the diabetes regimen in young people: the role of adolescent depressive symptoms.

AIMS: In young people with Type 1 diabetes, depressive symptoms and shared responsibility for management of diabetes impact upon diabetes management and control. However, the simultaneous effects of both depressive symptoms and parental involvement on diabetes self-care and glycaemic control have not been examined. Thus, the aim of the current study was to examine the relationships between parental involvement and adolescent depressive symptoms in predicting blood glucose monitoring and glycaemic control. METHODS: One hundred and fifty young people with Type 1 diabetes (mean age 15.3 years) and their parents completed responsibility sharing and depressive symptom assessments, meter assessment of blood glucose monitoring and HbA(1c) at baseline and then 6, 12 and 18 months. RESULTS: Parental involvement affected HbA1c through blood glucose monitoring only at low levels of adolescent depressive symptoms (score ≤ 6), which made up only 20% of the sample. In the presence of more depressive symptoms, parental involvement no longer was related to HbA1c through blood glucose monitoring. This was the relationship in the majority of the sample (80%). CONCLUSIONS: While most young people in this sample are not showing evidence of high levels of depressive symptoms, even modest levels of distress interfere with parental involvement in diabetes management. By addressing adolescent depressive symptoms, interventions promoting parental involvement in these families may be more effective.

Depressed patients have higher body temperature: 5-HT transporter long promoter region effects.

BACKGROUND: Depression has been associated with a decrease in intracellular serotonin (5-HT) reuptake through its transporter, SERT. The 5-HT transporter long promoter region (5-HTTLPR) deletion in the SERT gene has also been associated with a decrease in 5-HT reuptake. Conversely, increases in extracellular 5-HT have been associated with increased temperature. It has not been established, however, whether body temperature in depressed patients is different from controls. Here, we hypothesized that temperature would be increased in depressed patients as well as in those with the 5-HTTLPR deletion. METHODS: A strict oral temperature protocol employed single, cross-sectional, naturalistic time-of-day temperature measures in 125 subjects (46 normal controls, 79 outpatients with major depression). Controls and depressed patients were free of psychotropic medication and classified by the Structured Clinical Interview for Psychiatric Diagnoses. Eighty-one of the subjects (68 depressed, 13 normal) were additionally genotyped for 5-HTTLPR polymorphisms. RESULTS: Depressed patients had a significantly higher uncorrected body temperature (mean +/- SD 98.38 +/- 0.61 degrees F) than controls (mean +/- SD 98.13 +/- 0.59 degrees F; F = 4.8, p = 0.03). An age (F = 14.09, p < 0.001) and time-of-day (11.4, p = 0.001) correction revealed a more robust (F = 14.02, p < 0.001) difference between depressed patients (mean +/- SD 98.44 +/- 0.55 degrees F) and controls (mean +/- SD 98.02 +/- 0.56 degrees F). When normalized for age and circadian differences between subjects, random, outpatient oral temperatures had a sensitivity of 63% and a specificity of 76% in identifying the depressed subjects from the controls. Independent of depression, subjects with the 5-HTTLPR deletion (short SERT allele) were warmer (mean +/- SD 98.33 +/- 0.65 degrees F) than those lacking the short allele on either chromosome (mean +/- SD 97.91 +/- 0.69 degrees F; F = 7.0, p = 0.01). However, the genotype did not explain the temperature differences between controls and depressed patients. CONCLUSION: This is the first demonstration of an increased daytime body temperature in cases with major depression. Subjects with a corrected temperature above 98.3 degrees F were 2.6-fold more likely to be depressed. The results may strengthen the hypothesis of an inflammatory component of depression. In addition, the findings suggest a potential link between genetic differences in 5-HT transport and body temperature.

Scorecard endoscopy: a pilot study to assess basic skills in trainees for upper gastrointestinal endoscopy.

BACKGROUND: The development of training models and structured training courses for endoscopic techniques provides practical experience. To assess individual performance and progress in this training we developed and tested a scorecard system. METHODS: Three test groups were compared: group 1, ten physicians without previous endoscopic experience; group 2, ten students, without endoscopic experience; group 3, a control group of experienced endoscopists. Groups 1 and 2 underwent 1 week of training with a theoretical introduction and practical demonstrations. They were assessed by the scorecard daily by an experienced tutor. The individual scores and learning curves of the two beginner groups were compared with those of the expert group using a biosimulation model was used. RESULTS: Each participant improved significantly during the 1-week course. Mean scores on the first day in groups 1-3 were, respectively, 26.7+/-10.7, 33.4+/-5.3, and 72.0+/-5.8, and on day 6 they were 62.2+/-6.6, 63.4+/-7.6, and 86.6+/-4.3. The difference between group 3 and the other two groups was significant but not that between groups 1 and 2. CONCLUSIONS: Training in endoscopy can be assessed using our training model and our scorecard protocol, which distinguishes between various levels of experience. In physicians beginning in the field of gastrointestinal endoscopy this approach could help to reduce risks to patients, shorten learning curves, and exclude unskilled individuals from further fruitless interventions.

Antidepressant effects on kinase gene expression patterns in rat brain.

Multiple kinase pathways determine serotonin transporter (SERT) regulation. We hypothesized a decrease in kinase expression with chronic selective serotonin reuptake inhibitor (SSRI) administration necessary to regulate extracellular serotonin. We studied whole brain kinase mRNA expression on Affymetrix gene chips in rats treated with placebo 3 and 21 days, fluoxetine 3 and 21 days, and citalopram 21 days. Protein kinase C (PKC)-delta, PKC-gamma, stress-activated protein kinase, cAMP-dependent protein kinase beta isoform, Janus protein kinase, and phosphofructokinase M were all down regulated chronically with citalopram and fluoxetine, but not with acute fluoxetine. The results are consistent with homeostasis of SERT function through a decrease in PK expression.

A high-throughput screen for identifying transmembrane pore-forming peptides.

We have developed a visual microwell plate assay for rapid, high-throughput screening for membrane-disrupting molecules such as de novo designed pore formers, antibiotic peptides, bacterial toxins, and lipases. The detectability is based on the strong fluorescence emission of the lanthanide metal terbium(III) (Tb(3+)) when it interacts with the aromatic chelator dipicolinic acid (DPA). While Tb(3+) is not strongly fluorescent alone, the binary complex emits bright green fluorescence when irradiated with uv light. For the microwell plate assay, we prepared unilamellar phospholipid vesicles that had either Tb(3+) or DPA entrapped and the opposite molecule in the external solution. Disruption of the membranes allows the Tb(3+)/DPA complex to form, giving rise to a visibly fluorescent solution. In plates with 20-microl wells, the lower limit of visual detectability of the Tb(3+)/DPA complex in solution was about 2.5 microM. The lower limit of detectability using vesicles with entrapped Tb(3+) or DPA was about 50 microM phospholipid. We show that the membrane-disrupting effect of as little as 0.25 microM or 5 pmol of the pore-forming, antibiotic peptide alamethicin can be detected visually with this system. This sensitive, high-throughput assay is readily automatable and makes possible the visual screening of combinatorial peptide libraries for members that permeabilize lipid bilayer membranes.

HIV-1 reverse transcriptase interaction with model RNA-DNA duplexes.

HIV-1 reverse transcriptase (HIV-1 RT) is a multifunctional enzyme responsible for converting viral RNA into preintegrative DNA during the early stages of viral infection. DNA polymerase and RNase H activities are required, and several conformationally distinct primer-templates must be accommodated by the enzyme during the process. Parameters of interaction between model substrates (ligands) and HIV-1 RT (wild type p66/p51 and the RNase H-deficient mutant p66(E478Q)/p51) (analytes) were estimated by surface plasmon resonance at 25 degrees C, pH 8.0. Binding of RT to the ligands is specific and can be analyzed using a conventional 1:1 binding algorithm. RNA-DNA hybrids with 5'-template overhangs of 6 and 12 nucleotides bind to RT approximately one order of magnitude stronger than the corresponding 36-mer with blunt ends due to slower dissociation. Immobilization of the latter through either the 5'-end of RNA or DNA strand does not change the equilibrium constant (K(D)) for wild-type RT but the values of kinetic constants of association and dissociation differ significantly. For the p66(E478Q)/p51 enzyme, orientation effects are notable even altering the K(D) value. Binding of the p66(E478Q)/p51 to any RNA-DNA hybrids is slightly stronger compared with wild type. Data can be interpreted in terms of the mechanism of reverse transcription.

Sertraline treatment of posttraumatic stress disorder: results of 24 weeks of open-label continuation treatment.

BACKGROUND: Posttraumatic stress disorder (PTSD) is typically associated with a high degree of chronicity, comorbidity, and psychosocial disability. The efficacy of sertraline in the acute treatment of PTSD has been confirmed based on the results of 2 large, placebo-controlled studies, but almost no prospective long-term treatment studies have been reported. METHOD: One hundred twenty-eight patients who completed 12 weeks of double-blind, placebo-controlled, acute-phase treatment for DSM-III-R-defined PTSD with sertraline were continued into a 24-week open-label continuation phase. Efficacy was evaluated using the endpoint change in the 17-item Clinician Administered PTSD Scale Part 2 (CAPS-2) severity score, the 15-item patient-rated Impact of Event Scale, and the Clinical Global Impressions-Improvement and -Severity of Illness scales as primary outcome measures. Treatment response was defined as > or =30% decrease in the CAPS-2 total severity score (compared with acute-phase baseline score) and a Clinical Global Impressions-Improvement score of 1 or 2. RESULTS: Ninety-two percent of acute-phase responders maintained their response during the full 6 months of continuation treatment. In addition, 54% of acute-phase nonresponders converted to responder status during continuation therapy. Over the 36-week course of acute and continuation therapy, 20% to 25% of the improvement in the CAPS-2 severity score occurred during the continuation phase. Sertraline was well tolerated, with 8.6% of patients discontinuing due to adverse events. A high pretreatment CAPS-2 score (> 75) predicted a longer time to response and a greater likelihood that response occurred after 12 weeks of acute treatment. CONCLUSION: The acute efficacy of sertraline is sustained in the vast majority of patients, and at least half of nonresponders to acute treatment will eventually respond to continued treatment.

Fluvoxamine treatment of mixed anxiety and depression: evidence for serotonergically mediated anxiolysis.

Although increasing evidence suggests that selective serotonin reuptake inhibitor (SSRI) treatment may be effective for anxiety in addition to depression, SSRI anxiolysis has not been definitively related to the inhibition of serotonin (5-HT) transport. The gene that encodes for the human serotonin transporter (5-HTT) expresses its protein in neurons and in blood platelets, and both tissues respond to transport inhibition similarly in response to SSRI treatment. This study examined the relationship between the change in the 5-HTT's apparent affinity for 5-HT and the anxiolytic response in a group of 18 fluvoxamine-treated patients meeting Structured Clinical Interview for DSM-IV criteria for both generalized anxiety disorder and major depression. Significant decreases were found in both Hamilton anxiety and Hamilton depression scores over a 2-month treatment period. Robust increases were found in the apparent affinity constant (Km) for platelet 5-HT transport with treatment, and the increases covaried significantly with the decrease in anxiety (F = 4.97, p < 0.03). The pretreatment 5-HTT Km significantly correlated with the improvement in depression scores (r = 0.53, p < 0.03), consistent with the Hypothesis of Initial Conditions. These results suggest that the therapeutic effect of SSRI treatment can be linked to the magnitude and time-course of 5-HT transport inhibition effected with fluvoxamine, a drug that seems to have an antianxiety effect of the same magnitude as its effect on depression.

Serotonin reuptake is less efficient in taste aversion resistant than in taste aversion-prone rats.

We have previously reported the development of rat lines bred selectively for differences in taste aversion conditionability. Earlier studies demonstrated that the taste aversion resistant (TAR) animals exhibited lower concentrations of brain serotonin and consumed greater amounts of ethanol than their taste aversion prone (TAP) counterparts. In the present study, TAR rats demonstrated significantly less efficient brain serotonin transport compared to TAP rats, but the rat lines demonstrated similar levels of serotonin transporter or V(max) and similar whole brain paroxetine (a specific serotonin reuptake inhibitor) binding (B(max)). These results suggest that the rat lines differ in the mechanisms that transport serotonin into nerve endings, but do not differ in the binding of serotonin to the transporter or in the number of serotonin transport sites. The data support the hypothesis that genetically determined differences in the serotonin system contribute to individual differences in taste aversion conditionability. The findings further suggest that differences in serotonin transport may influence the propensity to self-administer ethanol.

Interaction of p55 reverse transcriptase from the Saccharomyces cerevisiae retrotransposon Ty3 with conformationally distinct nucleic acid duplexes.

The 55-kDa reverse transcriptase (RT) domain of the Ty3 POL3 open reading frame was purified and evaluated on conformationally distinct nucleic acid duplexes. Purified enzyme migrated as a monomer by size exclusion chromatography. Enzymatic footprinting indicate Ty3 RT protects template nucleotides +7 through -21 and primer nucleotides -1 through -24. Contrary to previous data with retroviral enzymes, a 4-base pair region of the template-primer duplex remained nuclease accessible. The C-terminal portion of Ty3 RT encodes a functional RNase H domain, although the hydrolysis profile suggests an increased spatial separation between the catalytic centers. Despite conservation of catalytically important residues in the RNase H domain, Fe(2+) fails to replace Mg(2+) in the RNase H catalytic center for localized generation of hydroxyl radicals, again suggesting this domain may be structurally distinct from its retroviral counterparts. RNase H specificity was investigated using a model system challenging the enzyme to select the polypurine tract primer from within an RNA/DNA hybrid, extend this into (+) DNA, and excise the primer from nascent DNA. Purified RT catalyzed each of these three steps but was almost inactive on a non-polypurine tract RNA primer. Our studies provide the first detailed characterization of the enzymatic activities of a retrotransposon reverse transcriptase.

Metal-ion stoichiometry of the HIV-1 RT ribonuclease H domain: evidence for two mutually exclusive sites leads to new mechanistic insights on metal-mediated hydrolysis in nucleic acid biochemistry.

Crystallographic studies of the Mn(2+)-doped RNase H domain of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) have revealed two bound Mn2+ separated by approximately 4A and surrounded by a cluster of four conserved carboxylates. Escherichia coli RNase H is structurally similar to the RNase H domain of HIV-1 RT, but requires one divalent metal cation for its activity, implying either that the HIV-1 RT RNase H domain contrasts in its ability to bind two divalent metal ions, or that the crystallographic data reflect specific use of Mn2+ and/ or the doping technique employed. Metal binding stoichiometry has been determined for Mn2+ and the biologically more relevant Mg2+ cation by solution calorimetric studies of native and recombinant p66/p51 HIV-1 RT. Three Mn2+ ions bind to HIV-1 RT apo-enzyme: one at the DNA polymerase and two at the RNase H catalytic center, the latter being consistent with crystallographic results. However, only one Mg2+ ion is bound in the RNase H catalytic center. Several mechanistic implications arise from these results, including the possibility of mutually exclusive Mg2+ binding sites that might be occupied according to the specific reaction being catalyzed by the multifunctional RNase H domain. The occurrence of distinct binding stoichiometries for Mg2+ and Mn2+ to multifunctional enzymes has previously been reported.

Probing contacts between the ribonuclease H domain of HIV-1 reverse transcriptase and nucleic acid by site-specific photocross-linking.

Cys(38) and Cys(280) of p66/p51 human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) can be converted to Ser without affecting enzyme function. We have exploited this feature to construct and purify "monocysteine" RT derivatives for site-specific modification with the photoactivable cross-linking agent, p-azidophenacyl bromide. Acylation of a unique cysteine residue introduced at the extreme C terminus of the p66 subunit (C(561)) with an azidophenacyl group allowed us to probe contacts between residues C-terminal to alpha-helix E' of the RNase H domain and structurally divergent nucleic acid duplexes. In a binary complex of RT and template-primer, we demonstrate efficient cross-linking to primer nucleotides -21 to -24/-25, and template nucleotides -18 to -21. Cross-linking specificity was confirmed by an analogous evaluation following limited primer extension, where the profile is displaced by the register of DNA synthesis. Finally, contact with a DNA primer hybridized to an isogenic RNA or DNA template indicates subtle alterations in cross-linking specificity, suggesting differences in nucleic acid geometry between duplex DNA and RNA/DNA hybrids at the RNase H domain. These data exemplify how site-specific acylation of HIV-1 RT can be used to provide high resolution structural data to complement crystallographic studies.