Photonic ring resonator filters for astronomical OH suppression.

Ring resonators provide a means of filtering specific wavelengths from a waveguide, and optionally dropping the filtered wavelengths into a second waveguide. Both of these features are potentially useful for astronomical instruments. In this paper we focus on their use as notch filters to remove the signal from atmospheric OH emission lines from astronomical spectra. We derive the design requirements for ring resonators for OH suppression from theory and finite difference time domain simulations. We find that rings with small radii (< 10 µm) are required to provide an adequate free spectral range, leading to high index contrast materials such as Si and Si3N4. Critically coupled rings with high self-coupling coefficients should provide the necessary Q factors, suppression depth, and throughput for efficient OH suppression, but will require post-inscription tuning of the coupling and the resonant wavelengths. The overall prospects for the use of ring resonators in astronomical instruments is promising, provided efficient fibre-chip coupling can be achieved.

Coping with stress in medical students: results of a randomized controlled trial using a mindfulness-based stress prevention training (MediMind) in Germany.

BACKGROUND: High prevalence rates of psychological distress in medical training and later professional life indicate a need for prevention. Different types of intervention were shown to have good effects, but little is known about the relative efficacy of different types of stress management interventions, and methodological limitations have been reported. In order to overcome some of these limitations, the present study aimed at evaluating the effect of a specifically developed mindfulness-based stress prevention training for medical students (MediMind) on measures of distress, coping and psychological morbidity. METHODS: We report on a prospective randomized controlled trial with three study conditions: experimental treatment (MediMind), standard treatment (Autogenic Training) and a control group without treatment. The sample consisted of medical or dental students in the second or eighth semester. They completed self-report questionnaires at baseline, after the training and at one year follow-up. Distress (Trier Inventory for the Assessment of Chronic Stress, TICS) was assessed as the primary outcome and coping (Brief COPE) as a co-primary outcome. Effects on the psychological morbidity (Brief Symptom Inventory, BSI) as a secondary outcome were expected one year after the trainings. RESULTS: Initially, N = 183 students were randomly allocated to the study groups. At one year follow-up N = 80 could be included into the per-protocol analysis: MediMind (n =31), Autogenic Training (n = 32) and control group (n = 17). A selective drop-out for students who suffered more often from psychological symptoms was detected (p = .020). MANCOVA's on TICS and Brief COPE revealed no significant interaction effects. On the BSI, a significant overall interaction effect became apparent (p = .002, η2partial = .382), but post hoc analyses were not significant. Means of the Global Severity Index (BSI) indicated that MediMind may contribute to a decrease in psychological morbidity. CONCLUSION: Due to the high and selective dropout rates, the results cannot be generalized and further research is necessary. Since the participation rate of the trainings was high, a need for further prevention programs is indicated. The study gives important suggestions on further implementation and evaluation of stress prevention in medical schools. TRIAL REGISTRATION: This trial is recorded at German Clinical Trials Register under the number DRKS00005354 (08.11.2013).

Effect of endurance training on dental erosion, caries, and saliva.

The aim of this investigation was to give insights into the impact of endurance training on oral health, with regard to tooth erosion, caries, and salivary parameters. The study included 35 triathletes and 35 non-exercising controls. The clinical investigation comprised oral examination, assessment of oral status with special regard to caries and erosion, saliva testing during inactivity, and a self-administered questionnaire about eating, drinking, and oral hygiene behavior. In addition, athletes were asked about their training habits and intake of beverages and sports nutrition. For saliva assessment during exercise, a subsample of n = 15 athletes volunteered in an incremental running field test (IRFT). Athletes showed an increased risk for dental erosion (P = 0.001). No differences were observed with regard to caries prevalence and salivary parameters measured during inactivity between athletes and controls. Among athletes, a significant correlation was found between caries prevalence and the cumulative weekly training time (r = 0.347, P = 0.04). In athletes after IRFT and at maximum workload, saliva flow rates decreased (P = 0.001 stimulated; P = 0.01 unstimulated) and saliva pH increased significantly (P = 0.003). Higher risk for dental erosions, exercise-dependent caries risk, and load-dependent changes in saliva parameters point out the need for risk-adapted preventive dental concepts in the field of sports dentistry.

[The neurobiology of anhedonia. The pathophysiology of an important symptom in depressive disorders]. / Neurobiologie der Anhedonie. Zur Pathophysiologie eines bedeutenden Symptoms der depressiven Störung.

The phenomenon of anhedonia, the inability to experience pleasure, is one of the essential elements for the diagnosis of depressive disorders. According to the criteria of both the ICD-10 and the DSM-IV, the presence of this symptom is crucial for the diagnosis of depressive disorders. In recent years scientific approaches using animal studies and projects of functional imaging have allowed the development of a new concept of the pathophysiology of anhedonia. The hypothesis that functional changes within the mesolimbic reward system could represent the neural correlate of anhedonia has contributed to a new concept of depressive disorders and allows testing of new therapeutic options for patients suffering from very resistant forms of depression. By using the method of deep brain stimulation present clinical studies try to ascertain whether the symptom of anhedonia can be alleviated by influencing the neural activity of the reward system. This article will give a critical overview about the background for new therapeutic approaches and illuminates the results of these studies.

[Removal of the laryngeal mask airway in the post-anesthesia care unit. A means of process optimization?]. / Geplante Entfernung der Kehlkopfmaske im Aufwachraum. Mittel zur Prozessoptimierung?

BACKGROUND: Removal of the laryngeal mask airway in the post-anesthesia care unit could potentially contribute to a faster turnover from one operation to the next. The aim of this study was, therefore, to obtain an insight into the potential time saving and the safety of planned removal of the ProSeal™-LMA (PLMA) in the post-anesthesia care unit. METHODS: In this study 120 adult patients with American Society of Anesthesiologists (ASA) classification I-II, age range 18-85 years, undergoing a surgical procedure under general anesthesia in which the PLMA was used were randomly assigned to one of two groups. In group I, the PLMA was removed in the awake patient in the operating room close to the end of the procedure. In group II, the anesthetised but spontaneously breathing patients were moved to the recovery room and the PLMA removed when the patient was awake. The anesthesia technique was standardized [balanced, sevoflurane, fentanyl, bispectral index-guided (BIS) target value=35±5] and identical in both groups until randomization. Patients were breathing room air during transport to the recovery room. Different time intervals as well as the incidence of critical incidents were compared between groups. An oxygen saturation (S(p)O(2)) value <95% was considered a clinically relevant and S(p)O(2) values <90% as clinically critical O(2)-desaturation. RESULTS: Removal of the PLMA took place after an average of 4.9±5.1 min in group I and after 19.5±9.6 min in group II. There was no difference in the availability of the anesthetist in the operating room for the following procedure between groups (group I: 12±5.6 min vs. group II: 10.7±4.2 min, p>0.05) despite the fact that patients of group II left the operating room faster (4.9±3.9 min) than patients of group I (7.1±5.1 min, p<0.01). In group II patients were ready for discharge (White score=12) from the recovery room later (13.2±8.2 min) than in group I (3.6±4.8 min, p<0.01). There were no significant differences in other process related time intervals between group I and group II: duration of the operation (113.2±45.9 min vs. 105.3±42.6 min), duration of dressing (5.1±3.7 min vs. 4.6±2.8 min), duration of transport to the recovery room (3.9±1.3 min vs. 3.6±1.3 min) and information at end of surgery by the surgeon (22.5±9.3 min vs. 22.4±10.5 min). The incidence of clinically relevant as well as clinically critical O(2) desaturation at the time of recovery room arrival (S(p)O(2)≤90%) was increased in group II with 33.3% vs. 56.6% and 13.3% vs. 6.7%, p<0.01, respectively. CONCLUSION: Planned PLMA removal in the recovery room after BIS-guided balanced anesthesia did not enable the anesthetist to be available earlier for induction of anesthesia in the following patient. Hence the anesthetist could not contribute to a faster turnover of cases. Obviously, with the type of close communication between surgeon and anesthetist dictated by the study protocol (announcement of expected end of surgery by the surgeon 20 min before end of surgery) it is possible for the patient to regain consciousness within a very small time window following the end of surgery. Following this kind of protocol, postponement of removal of the LMA in the recovery room does not seem to be attractive neither from a clinical nor an economic point of view. In contrast, removal of LMA in the recovery room should be restricted to occasional cases with an abrupt end of the operation or prolonged emergence from anesthesia. The obvious risk of hypoxemia necessitates continuous O(2) application and S(p)O(2) monitoring during transport to the recovery room.

[Acquired von Willebrand's disease type 2A following arteriovenous fistula for haemodialysis?]. / Erworbenes von-Willebrand-Syndrom Typ 2A als Begleiterscheinung eines Dialyseshunts?

Acquired von Willebrand's disease (aVWD) is considered to be an underestimated cause of unexplained bleeding. Adsorption of von Willebrand factor (VWF) to tumour cells or hydroxyethyl starch and elimination of VWF by autoantibodies as well as shear stress-induced mechanical alteration of VWF with concomitant cleavage by enzymes may lead to an acquired deficiency of VWF and a bleeding disorder. We report a 39-year-old woman who developed spontaneous bleeding five years after surgical creation of an arteriovenous fistula (AVF) for haemodialysis treatment. AVWD type 2A was diagnosed after successful renal transplantation. One year after surgical closure of the AVF, the aVWD could not be verified again. Thus, the aVWD may have developed because of altered blood flow and shear stress inside the arteriovenous fistula.

Hormone-stimulated calcium release is inhibited by cytoskeleton-disrupting toxins in AR4-2J cells.

We have studied the role of the actin cytoskeleton in bombesin-induced inositol 1,4,5-trisphosphate (IP(3))-production and Ca(2+)release in the pancreatic acinar tumour cell line AR4-2J. Intracellular and extracellular free Ca(2+)concentrations were measured in cell suspensions, using Fura-2. Disruption of the actin cytoskeleton by pretreatment of the cells with latrunculin B (10 microM), cytochalasin D (10 microM) or toxin B from Clostridium difficile (20 ng/ml) for 5-29 h led to inhibition of both, bombesin-stimulated IP(3)-production and Ca(2+)release. The toxins had no effect on binding of bombesin to its receptor, on Ca(2+)uptake into intracellular stores and on resting Ca(2+)levels. Ca(2+)mobilization from intracellular stores, induced by thapsigargin (100 nM) or IP(3)(1 microM) was not impaired by latrunculin B. In latrunculin B-pretreated cells inhibition of both, bombesin-stimulated IP(3)- production and Ca(2+)release was partly suspended in the presence of aluminum fluoride, an activator of G-proteins. Aluminum fluoride had no effect on basal IP(3)and Ca(2+)levels of control and toxin-pretreated cells. We conclude that disruption of the actin cytoskeleton impairs coupling of the bombesin receptor to its G-protein, resulting in inhibition of phospholipase C-activity with subsequent decreases in IP(3)-production and Ca(2+)release.

Stereological quantification of carboxyfluorescein-labeled rat lung metastasis: a new method for the assessment of natural killer cell activity and tumor adhesion in vivo and in situ.

The function of natural killer (NK) cells is often studied by assessing in vitro levels of NK cell mediated lysis of target cells, or by assessing in vivo levels of lung tumor cell retention or metastatic colonization of intravenously injected tumor cells. However, these methods do not permit direct quantification and visualization of NK cells and their targets in vivo and in situ. Here, a new approach is described to visualize effector-to-target interactions as well as to estimate total numbers of targets in the lung, in vivo and in situ. MADB106 tumor cells were vitally labeled using carboxyfluorescein (CFSE) and intravenously (i.v.) injected into Fischer 344 rats (10(6) cells/rat). This mammary adenocarcinoma derived cell line is syngeneic to the inbred Fischer 344 rat and highly sensitive to NK cell activity in vivo. Effector-to-target interactions were visualized by immunostaining. Using the optical fractionator method, total numbers of CFSE-labeled MADB106 tumor cells were estimated in the left lung of the animals 5 min after tumor inoculation. To further demonstrate the usefulness of this approach in reflecting in vivo processes, rats were inoculated with MADB106 cells and simultaneously with a single i.v. bolus of either 1 microg/kg adrenaline or saline. Both lungs were removed 5 min later. Adrenaline caused a significant 80% reduction in the total number of lung CFSE-labeled MADB106 tumor cells, suggesting a rapid modulation of metastasis by stress hormones. This new approach facilitates the monitoring of effector-to-target interactions and the quantification of immune cell function or tumor adhesion in vivo and in situ.

Differential effects of neuropeptide Y (NPY) on leukocyte subsets in the blood: mobilization of B-1-like B-lymphocytes and activated monocytes.

Sympathetic nervous system activation mobilizes leukocytes but it is unknown whether the concomitant neuropeptide Y (NPY)-release also alters blood leukocyte counts. Using chronic intravenous (i.v.) cannulation of freely moving rats and flow cytometry, time-, dose- and subset-specific effects of NPY on blood leukocytes were investigated 1-15 min after injection: High-dose NPY increases leukocytes numbers by preferentially mobilizing CD4(+) T-cells, activated NKR-P1A(+) monocytes and NK-cells. Low-dose NPY significantly decreases B-lymphocyte and NK-cell numbers. Furthermore, NPY dose-dependently mobilizes a previously undetected IgM(low)CD5(+)CD11b(+) B-cell subpopulation in rats ("B1-like" B-lymphocytes). These data suggest a role for the sympathetic neurotransmitter NPY in neuroimmune alterations in vivo.

Corn1: a mouse model for corneal surface disease and neovascularization.

PURPOSE: To describe a new mouse model of corneal surface disease and neovascularization. METHODS: Anatomic changes were demonstrated in corn1 and control A.By/SnJ mice from day 10 of gestation of 8 months of age by routine techniques of light microscopic and scanning electron microscopy. Corneal epithelial cell kinetics were evaluated by labeling cells in the "S" phase of the cell cycle by intraperitoneal injection of tritiated thymidine. Labeled cells were counted under 250X magnification, and the length of the corneal epithelial chord was measured by morphometric techniques. Results were expressed as labeled cells per linear millimeter of corneal epithelium. The corn1 locus was mapped using selected back-crosses. RESULTS: Corn1 is characterized by early, irregular thickening of the corneal epithelium, development of stromal neovascularization by 20 days of age, and cataract by 48 days of age. Corneal epithelial cell kinetics demonstrated prominent labelling of corn1 mice at 30 days of age compared to the control mice. Corn1 behaves as an autosomal recessive gene and is located on mouse chromosome 2, approximately 5.2 cM from the agouti locus. Heterozygotes have no corneal disease. CONCLUSIONS: Corn1 mice, with genetically determined corneal epithelial hyperplasia and stromal neovascularization, may be particularly useful in studies of neovascularization and corneal surface proliferative disease.

Cortisol and memory retrieval in humans: influence of emotional valence.

Glucocorticoids secreted in response to stress modulate memory in animals and humans. Studies in rodents suggest that glucocorticoids enhance memory consolidation but impair delayed retrieval. Similar negative effects on memory retrieval have been reported in humans. The human studies so far have not addressed the issue of emotional valence, which conceivably could modulate the effects of cortisol on retrieval. The present mini-review discusses two recent studies from our laboratories that investigate the influence of emotional valence on the retrieval-impairing effects of cortisol. Both studies observed that cortisol impaired retrieval and that emotional valence influenced these effects. For autobiographical memory the impairing effects were stronger for neutral than for emotional items, whereas for word retrieval the opposite pattern was observed (stronger effects on emotional words). Possible reasons for these results are the different memory domains tested as well as the different sex of the subjects. Future studies will address these issues, which are of relevance for psychiatric disorders such as posttraumatic stress disorder or major depression.

Experimental prevention of bitterweed (Hymenoxys odorata) poisoning of sheep.

To examine the effects on bitterweed toxicity of dietary factors known to increase thiol concentrations in the body, 36 lambs were fed one of the following diets (12 lambs/diet) for a minimum of 9 days prior to bitterweed administration: diet 1, 10% crude protein; diet 2, 20% crude protein, 0.5% methionine, 0.5% sodium sulfate, and 1,102 IU of vitamin E/kg; and diet 3, diet 2 with 0.5% ethoxyquin hydrochloride added. Four lambs fed each diet were euthanatized prior to bitterweed administration (initial euthanasia group). Four lambs fed each diet were administered bitterweed (0.68% hymenoxon, air-dried basis) at a rate of 0.25% of live weight for 5 consecutive days. The remaining four lambs on each diet served as unchallenged controls. In the initial euthanasia group, diet 2 increased extracellular blood thiol concentrations (1.12 vs 0.94 mg of SH/d1, P less than 0.10), rumen fluid thiol concentrations (4.46 vs 1.88 mg of SH/d1, P less than 0.05), and liver thiol concentrations (263.6 vs 109.3 micrograms SH/g of wet wt, P less than 0.05), compared with diet 1. Ethoxyquin hydrochloride (diet 3) reduced blood thiol concentrations (0.94 vs 1.12 mg of SH/dl, P less than 0.10) and liver thiol concentrations (151.6 vs 263.6 micrograms of SH/g of wet wt, P less than 0.05), compared with diet 2. Kidney thiols were unaffected by treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of expander cottonseed meal in broiler diets formulated on a digestible amino acid basis.

This experiment was designed to evaluate the use of expander cottonseed meal (CSM) in broiler diets formulated on a digestible amino acid basis and to determine the tissue distribution of gossypol enantiomers and their relationship to gossypol consumption. Gossypol is an antinutritional polyphenolic pigment found in cottonseed. A total of 800 1-d-old broilers (Arbor Acres) was randomly divided into 40 groups of 20 birds each and placed in a broiler house with wood shavings litter. The CSM was included in starter and grower diets at 0, 7, 14, 21, and 28% of the diet. Diets were formulated to have similar levels of digestible methionine and lysine as the 0% CSM control diet. At 21 d of age, five birds per pen were randomly selected for the determination of gossypol enantiomers in plasma, liver, heart, and breast muscle. Tissues were again collected at 42 d of age. Results of this experiment indicated that at 21 d of age cumulative body weight and feed-to-BW ratios of birds fed CSM diets were not significantly different from the control. By 35 d of age, feed-to-BW ratios of experimental birds fed the 28% CSM diet were significantly greater than the control birds, and by 42 d, BW were lower than those of the control group. Tissue concentrations of total, (+) and (-) gossypol increased linearly as the level of CSM increased. At 42 d, liver had the most gossypol with a ratio of 87% (+) gossypol to 13% (-) gossypol. Plasma contained 73% (+) gossypol and 27% (-) gossypol. Heart contained 45% (+) gossypol and 55% (-) gossypol. Breast muscle had the least gossypol. Results of this experiment indicated that expander solvent CSM could be fed to broilers at up to 21% of the total diet if amino acid digestibility was considered.

Tissue distribution of gossypol enantiomers in broilers fed various cottonseed meals.

Plasma and tissue concentrations of total, (+)- and (-)-gossypol were determined in broilers fed cottonseed meals (CSM) from eight oil mills (five expander solvent, two expeller, and one direct solvent). Free gossypol in the meals ranged from 0.033 to 0.180%, and total gossypol ranged from 0.974 to 1.459%. The (+)-enantiomer of gossypol varied from 53.8 to 61.3% of total gossypol. Eight CSM diets containing 28% CSM and a soybean meal control diet were fed to 162 1-d-old male broiler chicks during a 3-wk starter period. Concentrations of free gossypol in the CSM diets ranged from 92 to 504 microg/g, and total gossypol ranged from 2,626 to 4,085 microg/g. All diets were formulated with the same concentrations of digestible lysine and methionine and were fed ad libitum. At 21 d of age, there were no significant differences in body weights, feed conversions, or mortality of birds fed the CSM diets when compared to birds fed the soybean meal diet. Concentrations of (+)- and (-)-gossypol in plasma, liver, kidney, and muscle increased linearly as the level of free gossypol increased in the diets. Liver had the highest concentration of total gossypol (71.4 to 313.6 microg/g DM) followed by kidney (9.2 to 36.3 microg/g DM), plasma (3.0 to 14.6 microg/mL), and muscle (2.1 to 9.8 microg/g DM). The proportion of (-)-gossypol was higher in plasma (26.7%) and kidney (25.6%) than in muscle (19.1%) and liver (16.0%). Performance data from this study indicate CSM can be used successfully in chick starter diets at levels up to 28% when diets are formulated on a digestible amino acid basis.

Electrical properties of oligodendrocytes in culture.

The electrical properties of immunocytologically identified oligondendrocytes from embryonic mouse spinal cord maintained in culture for 3 to 6 weeks studied by passing current and recording potential changes with two separate intracellular electrodes. The average input resistance was 3.3 M omega and ranged from 0.7 to 16 M omega (n = 35). The input resistance increased by 19% with depolarization and decreased by 9% with hyperpolarization of 25 mV. The membrane time constant determined from the slope of the late exponential tail was 3.45 +/- 2.5 ms SD (n = 15). The specific membrane resistance of three cells was determined by a simplified square pulse analysis combined with measurement of membrane area. Membrane area was estimated from photomicrographs of cells injected with Lucifer Yellow CH and stained with the cell surface-reactive antibody 04 and from electron micrographs. An average specific membrane resistance of 1.3 X 10(3) omega cm2 and specific capacitance of 1.7 mu F/cm2 were calculated. Increasing [K+]o depolarized the cells and decreased the input resistance and the time constant.

Deoxypodophyllotoxin 6-hydroxylase, a cytochrome P450 monooxygenase from cell cultures of Linum flavum involved in the biosynthesis of cytotoxic lignans.

Cell-suspension cultures of Linum flavum L. (Linaceae) synthesize and accumulate aryltetrahydronaphthalene lignans with 6-methoxypodophyllotoxin as the main component. The experimental data indicate that the biosynthesis of 6-methoxypodophyllotoxin occurs via deoxypodophyllotoxin, beta-peltatin, and beta-peltatin-A methyl ether. The enzyme catalyzing the introduction of the hydroxyl group in position 6 is deoxypodophyllotoxin 6-hydroxylase (DOP6H). The enzyme was shown to be a cytochrome P450-dependent monooxygenase by blue-light reversion of carbon monoxide inhibition and inhibition by cytochrome c. DOP6H is a membrane-bound microsomal enzyme with a pH optimum of 7.6 and a temperature optimum of 26 degrees C. Deoxypodophyllotoxin is specifically accepted with an apparent Km of 20 microM and a saturation concentration of 200 microM; 4'-demethyldeoxypodophyllotoxin is the only other tested substrate accepted for hydroxylation. DOP6H predominantly accepts NADPH as electron donor; NADH can only sustain low hydroxylation activities. A synergistic effect of NADPH and NADH is not observed. The enzyme is saturated around 250 microM NADPH; the apparent Km for this substrate is 36 microM.