Morphology and chemical composition of cobalt germanide islands on Ge(001).

The reactive growth of cobalt germanide on Ge(001) was investigated by means of in situ x-ray absorption spectroscopy photoemission electron microscopy (XAS-PEEM), micro-illumination low-energy electron diffraction (µ-LEED), and ex situ atomic force microscopy (AFM). At a Co deposition temperature of 670 °C, a rich morphology with different island shapes and dimensions is observed, and a correlation between island morphology and stoichiometry is found. By combining XAS-PEEM and µ-LEED, we were able to identify a large part of the islands to consist of CoGe2, with many of them having an unusual epitaxial relationship: CoGe2 [Formula: see text] [Formula: see text] Ge [Formula: see text]. Side facets with (112) and (113) orientation have been found for such islands. However, two additional phases were observed, most likely Co5Ge7 and CoGe. Comparing growth on Ge(001) single crystals and on Ge(001)/Si(001) epilayer substrates, the occurrence of these intermediate phases seems to be promoted by defects or residual strain.

Subunit selectivity and epitope characterization of mAbs directed against the GABAA/benzodiazepine receptor.

mAbs bd 17, bd 24, and bd 28 raised against bovine cerebral gamma-aminobutyric acid (GABAA)/benzodiazepine receptors were analyzed for their ability to detect each of 12 GABAA receptor subunits expressed in cultured mammalian cells. Results showed that mAb bd 17 recognizes epitopes on both beta 2 and beta 3 subunits while mAb bd 24 is selective for the alpha 1 subunit of human and bovine, but not of rat origin. The latter antibody reacts with the rat alpha 1 subunit carrying an engineered Leu at position four, documenting the first epitope mapping of a GABAA receptor subunit-specific mAb. In contrast to mAbs bd 17 and bd 24, mAb bd 28 reacts with all GABAA receptor subunits tested but not with a glycine receptor subunit, suggesting the presence of shared epitopes on subunits of GABA-gated chloride channels.

Functional and molecular distinction between recombinant rat GABAA receptor subtypes by Zn2+.

gamma-Aminobutyric acid receptor (GABAAR) channels in different neurons display heterogeneous functional properties. Molecular cloning revealed a large number of GABAAR subunits that assemble into GABAAR subtypes with different functional properties, suggesting that the subunit combination determines the functional properties of the receptor. In this study, the subunit composition of GABAARs is related to a functional distinction between Zn2(+)-sensitive and Zn2(+)-insensitive receptor subtypes. GABAARs reconstituted in transiently transfected fibroblasts from combinations of cDNAs encoding alpha and beta subunits are potently blocked by Zn2+. The presence of a gamma subunit in any combination with the other subunits leads to the formation of GABAARs that are almost insensitive to Zn2+. These data provide a structural correlate to the functional heterogeneity of the action of Zn2+ on GABAARs in native membranes and show that Zn2+ insensitivity of GABA-activated currents indicates the presence of a gamma-subunit in the assembled GABAAR channel.

Rapid down regulation of Ca2+ signals induced by endothelin-1 in a human bronchial epithelial cell line.

Ca2+ transients evoked by endothelin-1 (ET-1) were measured in single cells of an immortalized human tracheal epithelial cell line using Fura-2. ET-induced Ca2+ transients were compared to signals evoked via established phospholipase-C linked receptors (H1 histamine; P2y purinergic, ATP). Saturating concentrations of histamine (100 microM) and ATP (10 microM) caused Ca2+ transients of identical amplitude, whereas a saturating concentration of ET-1 (10 nM) on average resulted in a slightly smaller change in fluorescence ratio (80 +/- 27%). H1 and P2y induced Ca2+ signals caused by brief (10-30 s) application of the agonists were highly reproducible. No desensitization to these ligands was observed, if between two exposures cells were superfused with agonist-free solution for > or = 200 s. A single exposure to ET-1 (10 nM) for > or = 6 s reduced sensitivity of the cell to a second exposure to ET-1. On average, the signal upon a second application of 10 nM ET-1 had an amplitude of 30% of the first ET-1 induced signal in that cell. After two 10 s exposures to the peptide, less than 10% of the initial amplitude was measured. This desensitization did not affect responsiveness to histamine or ATP. No recovery from desensitization to ET-1 was observed for 12 h after a single brief treatment with the peptide. Thereafter, responsiveness to ET-1 re-appeared with a half time of about 5 h and was complete by about 20 h. Ca2+ signals to all three agonists were absent in thapsigargin treated cells. Their amplitude was not affected by superfusion of the cells with Ca(2+)-free solution. Under conditions of store-depletion either by ET-1 or by thapsigargin, a change from Ca(2+)-free to Ca(2+)-containing solution induced a slow rise in [Ca2+]i, suggesting the existence of a capacitative Ca2+ entry pathway. ET-receptors most likely of the ETA subtype are subject to a novel type of desensitization-at least with regard to Ca2+ signalling-which might reflect a signal transduction mechanism specific to ET receptors.

Cyclical patterns of states of mind in psychotherapy.

OBJECTIVE: A quantitative study of shifts in states of mind was conducted to demonstrate a clinically useful mode of observation. This mode categorizes observations of a patient's mental state into well-modulated, overmodulated, undermodulated, and shimmering patterns. METHOD: The authors used reliable systems for scoring a patient's state of mind on videotapes of all sessions of her brief psychotherapy and, using separate procedures, scored the topics of discourse. These data were then examined by means of a lagged log-linear sequential analysis for patterns of shifts from one state to another and for concurrent shifts in topics. RESULTS: The findings indicated nonrandom shifts in state. Patterns of shifting from a well-modulated state to alternative states and back again were overrepresented. Such shifts were related to conflictual topics of discourse. CONCLUSIONS: Observing such shifts in mental state may help psychotherapists to formulate the contents of conflict and also to make technical interventions to stabilize optimal states for doing the work of psychotherapy.

Environmental sex determination in a reptile varies seasonally and with yolk hormones.

Most hypotheses that have been put forward in order to explain the persistence of environmental sex determination (ESD) in reptiles assume a relatively fixed association of sex with temperature-induced phenotype and no maternal influence on offspring sex. Here we demonstrate the association of maternally derived yolk hormone levels with the offspring sex ratio and describe two new aspects of temperature-dependent sex determination (TSD), i.e. seasonal variation in both thermal response and yolk steroid levels. Eggs from painted turtles (Chrysemys picta) were incubated at 28 degrees C. The hatchling sex ratio at 28 degrees C (i.e. the phenotypic reaction norm for sex at 28 degrees C) shifted seasonally from ca. 72% male to ca. 76% female. Yolk oestradiol (E2) increased seasonally while testosterone (T) decreased. The proportion of males in a clutch decreased as E2 levels increased and the E2:T ratio increased. These new findings are discussed in relation to heritability and adaptive explanations for the persistence of ESD in reptiles. Maternally derived yolk hormones may provide a mechanism for the seasonal shift in the sex ratio which in turn may help explain the persistence of ESD in reptiles. They may also explain those clutches of other reptiles with TSD that fail to yield only males at maximally masculinizing conditions.

Comparison of in vitro binding properties of a series of dopamine antagonists and agonists for cloned human dopamine D2S and D2L receptors and for D2 receptors in rat striatal and mesolimbic tissues, using [125I] 2'-iodospiperone.

We investigated the ligand binding properties in vitro of two splice variants of the cloned human dopamine D2 receptor (the 443 and 414 amino acids long forms called D2L and D2S, respectively), expressed in 293 human kidney cells, in comparison with those of the dopamine D2 receptors in rat striatum, nucleus accumbens and tuberculum olfactorium. The new radioligand, [125I]2'-iodospiperone, showed a similar high binding affinity (KD:0.056-0.122 nM) for cloned human D2S and D2L receptors and for the D2 receptors in the three rat brain areas. Binding affinities of 25 dopamine antagonists and of 10 dopamine agonists belonging to different chemical classes were measured. The IC50 values of the antagonists were virtually identical in the five preparations: spiperone was the most potent compound (pIC50 approximately 9.9), remoxipride the least potent one (pIC50 approximately 5.7). The agonists showed similar IC50 values for the cloned human D2S and D2L receptors but their affinity for rat brain D2 receptors was 2- to 5-fold higher. Dopamine showed shallow inhibition curves, the high affinity binding was 10-fold lower for the cloned human D2 receptors than for the rat brain D2 receptors. Addition of stable guanosine-5'-triphosphate (GTP) analogues shifted the D2 receptors in the rat brain tissues to the "low" affinity state, the low affinity binding of dopamine was equal to the affinity for the cloned human receptor. None of the dopamine antagonists or agonists could differentiate between the two splice forms of the cloned human D2 receptors or between the D2 receptors in rat striatal and mesolimbic tissues. The lower apparent affinity of some agonists and of dopamine in the absence of stable GTP analogues suggests a less appropriate receptor G-protein coupling for the cloned human D2 receptors expressed in the 293 human kidney cells. Unexpectedly, guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S) reduced the [125I]2'-iodospiperone binding to the D2 receptors by 20-35% in the rat brain tissues and the cloned human D2L receptor, and by 75% to the cloned human D2S receptor. The inhibition in the last case could be prevented partly by submicromolar concentrations of dopamine. The GTP-gamma-S effect is suggested to be due to reduction of disulphide bonds in the receptor. Recent molecular modelling studies indicated an important role of the disulphide bridge between Cys107 at the start of transmembrane domain three and Cys182 in the third extracellular loop, for the binding of dopamine to the D2 receptor.

Influence of tidal volume on respiratory compliance in anesthetized infants and young children.

Recent studies have suggested a close association between total respiratory compliance (Crs) and tidal volume in anesthetized paralyzed infants who are being artificially ventilated. To investigate this further, the multiple occlusion technique was used to measure Crs in 20 anesthetized infants and young children (aged 1-25 mo) before elective surgery. Measurements were made after intubation 1) during spontaneous breathing (SB), 2) after administration of a non-depolarizing muscle relaxant with tidal volume and frequency mimicking that during SB, and 3) with the child still paralyzed but tidal volume approximately double that during SB. Compared with values obtained during SB, there was no significant change in Crs after paralysis when ventilation matched the child's own pattern (P greater than 0.2). When ventilated with the larger tidal volumes, the infants showed a highly significant increase in Crs (mean 62%, range 14-158%, P less than 0.0001). These results may have implications not only for studies performed during anesthesia but also when infants were monitored in the intensive care setting. Values of Crs obtained in ventilated infants may reflect both the mechanical behavior of the respiratory system and the pattern of ventilation at the time of measurement.

A prominent epitope on GABAA receptors is recognized by two different monoclonal antibodies.

The monoclonal antibody 62-3G1 raised against the GABAA/benzodiazepine receptor complex was tested for its subunit selectivity using recombinantly expressed GABAA receptor subunits. The antibody bound selectively to beta 2 and beta 3 but not beta 1 nor any other GABAA receptor subunit. Using enzyme-linked immunosorbent assay, the epitope on beta 2 and beta 3 subunits was determined to be residues 1-3. MAb bd 17, which displays identical subunit selectivity as mAb 62-3G1, was seen to bind to the same epitope. These results resolve the subunit selectivity of mAbs 62-3G1 and bd 17 and reveal the identity and localization of a prominent immunogenic epitope on the GABAA/benzodiazepine receptor.

Inverse but not full benzodiazepine agonists modulate recombinant alpha 6 beta 2 gamma 2 GABAA receptors in transfected human embryonic kidney cells.

We compared the modulation of GABA (gamma-aminobutyric acid)-activated currents by benzodiazepines in recombinant GABAA receptors containing either one of two alpha subunits, alpha 1 or alpha 6. Lüddens et al. (Nature, 346 (1990) 648-651) have previously demonstrated that the alpha 6 subunit is part of a cerebellar receptor subtype which selectively binds Ro15-4513, an antagonist of alcohol-induced motor ataxia. Here we report that the imidazobenzodiazepine Ro15-4513 (ethyl 8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo-(1,5-a) (1,4)benzodiazepine-3-carboxylate) reduced GABA-activated currents in recombinant alpha 6 beta 2 gamma 2 and alpha 1 beta 2 gamma 2 receptors, thus acting consistently as an inverse agonist. Moreover, another well characterized negative modulator, DMCM (methyl-4-ethyl-6,7-dimethoxy-beta-carboline-3-carboxylate), also reduces GABA activated-currents in both receptors. In contrast, flunitrazepam (FNZM), a benzodiazepine agonist, increases GABA-activated currents in alpha 1 beta 2 gamma 2 receptors, but not in alpha 6 beta 2 gamma 2 receptors. This study lends further support to the hypothesis that the binding sites of full and partial inverse agonists are different.

Differential benzodiazepine pharmacology of mammalian recombinant GABAA receptors.

We compared gamma-aminobutyric acid (GABA)-activated currents and their modulation by benzodiazepines in cultured human cells transfected with complementary desoxyribonucleic acid (cDNA) encoding different GABAA receptor subunits. Flunitrazepam, a benzodiazepine agonist which potentiates GABA responses in both neurons and astrocytes was only effective in receptors containing the gamma 2 subunit (alpha 1 beta 1 gamma 2 and alpha 5 beta 1 gamma 2). The beta-carboline methyl-4-ethyl-6,7-dimethoxy-beta-carboline-3-carboxylate (DMCM) decreased GABA-activated currents in receptors composed of alpha 1 beta 1 gamma 1 and alpha 1 beta 1 gamma 2 subunits but increased GABA-activated currents in receptors containing the alpha 5 subunit (alpha 5 beta 1 gamma 1 and alpha 5 beta 1 gamma 2). These results strongly suggest that flunitrazepam and DMCM do not act on isosteric sites and that differences in the responsiveness of GABAA receptors to these compounds are based on different subunit compositions of GABAA receptors.

Topics and signs: defensive control of emotional expression.

This single-case study examined frank disclosure of important topics in a brief exploratory psychotherapy, including topics closely related to a recent, unintegrated stressor life event. Quantitative measures of emotion and control variables showed heightened levels of both emotionally and defensive control during discourse on the topic of the stressor event. In future studies, such measures of verbal and nonverbal signs of emotional expression and defensive control might be used to identify topics in an unresolved state.

Pathological grief: an intensive case study.

Pathological mourning is such an excessive, blocked, or distorted process that psychiatric signs and symptoms develop. Explanation of how and why these signs and symptoms form could deepen an understanding of both normal and pathological mourning. Because many variables are involved in such explanations, intensive case study is a desirable methodology because it permits a detailed look at how various factors interact (Brewer and Hunter 1989; Luborsky and Mintz 1972; Luborsky and Spence 1971; Nessleroade and Ford 1985). While a patient may complain of symptoms as experiences that endure or occur episodically over days and weeks, a clinician observes psychiatric signs in the here-and-now seconds and minutes of an interview. Relating signs and symptoms to each other and to other variables in order to form a theoretical model of their formation requires exploration of data across long and short time frames. It is important to understand how the here-and-now phenomena combine to form patterns across longer periods of the individual's life. Hence, we developed a combined macro- and microanalytic approach to intensive case studies.

Life support approaches for Mars missions.

Life support approaches for Mars missions are evaluated using an equivalent system mass (ESM) approach, in which all significant costs are converted into mass units. The best approach, as defined by the lowest mission ESM, depends on several mission parameters, notably duration, environment and consequent infrastructure costs, and crew size, as well as the characteristics of the technologies which are available. Generally, for the missions under consideration, physicochemical regeneration is most cost effective. However, bioregeneration is likely to be of use for producing salad crops for any mission, for producing staple crops for medium duration missions, and for most food, air and water regeneration for long missions (durations of a decade). Potential applications of in situ resource utilization need to be considered further.

[Factors affecting pregnancy rates in the German Thoroughbred Breed]. / Einflussfaktoren auf die Trächtigkeitsrate in der deutschen Vollblutzucht.

OBJECTIVE: The aim of this study was to evaluate factors affecting pregnancy rates in the German Thoroughbred Breed with particular emphasis on optimisation of fertility rates for breeding stallions of older ages. MATERIAL AND METHODS: Data from the studbooks of the German Thoroughbred Breeding Association from 1996 to 2009 analysed. This analysis included the records of 319 stallions and 6622 brood mares, resulting in 21,372 pregnancies at the end of the season. RESULTS: Pregnancy rates were significantly affected by the age of the stallion and mare as well as the season (month in the breeding season in which covering occurred). Furthermore, significant interactions were found between stallion age and book (number of mares covered per stallion), and between stallion age and season. Pregnancy rates decreased with increasing age of the stallion and brood mare as well as with the progression of the breeding season. However, stallions older than 16 years did show higher pregnancy rates when booked for more than 12 brood mares per season. Pregnancy rates for the older stallions were in particular decreased for later months in the breeding season. CONCLUSION AND CLINICAL RELEVANCE: For breeding with older stallions mares should be bred as early as possible in the breeding season and a sufficiently large number of mares should be covered.

[Stability of antilipidemic etofibrate and its metabolites towards gastrointestinal and blood hydrolases (author's transl)]. / Zur Stabilität des Blutlipidsenkers Etofibrat und seiner Metabolite gegenüber Hydrolasen des Gastrointestinaltraktes und des Blutes.

Etofibrate is preferentially cleaved in its clofibrinic acid ester group by the hydrolases of the blood. The formed nicotinic acid 2-hydroxyethyl ester is considerably more stable than the 2-(4-chlorophenoxy)-2-methylpropionic acid (2-hydroxyethyl)-ester. Against artificial gastric and intestinal juice (USP XIX), the nicotinic acid 2-hydroxyethyl ester is almost completely stable. Etofibrate is bound to plasma albumin substantially more tightly than is clofibrate.

States of emotional control during psychotherapy.

The authors' objective was to develop a simple and reliable descriptive method for categorizing patient states during psychotherapy. The categories would be based on the degree of apparent control over emotional expressions. Methods involved scoring videotapes of psychotherapy for 5 patients with neurotic-level Axis I disorders. Three judges rated each 30-second segment as predominantly one of these four states: well modulated, overmodulated, undermodulated, or shimmering. Shimmering states combine emotional display with efforts to stifle that expression. The results showed that judges could reliably rate states by the definitions used in this study. This technique can provide a simplified and general approach to observation of degrees of defensive control of emotion of patients in psychotherapy.

Comparative single-dose kinetics of amitriptyline and its N-oxide in a volunteer.

Plasma drug levels and urinary metabolites were measured in a volunteer for 28 h after ingestion of amitriptyline hydrochloride or amitriptyline N-oxide (amitriptylinoxide) equivalent to 100 mg of amitriptyline base. The N-oxide initially produced high plasma levels and 15% of the dose was excreted unchanged within 14 h. From comparison of the metabolite excretions, it can be concluded that about 70% of the dose was reduced at the N-oxide group, while comparison of the areas under the plasma group, while comparison of the areas under the plasma level-time curves for amitriptyline pointed to a 55% reduction to the amine. Less drowsiness was experienced after ingesting the N-oxide, and there was no depressive mood.

Antipeptide antibodies differentiate between long and short isoforms of the D2 dopamine receptor.

We have developed specific antibodies directed against two synthetic peptides corresponding to defined sequences in the D2 dopamine receptor. One peptide is from a region that is present only in the 'long' isoform of the receptor, whereas the other is from a region that is common to both. These antibodies are able to recognize the native receptor as judged by immunocytochemical staining of cells transfected with dopamine receptor DNA. One antibody was shown to be specific for the 'long' form of the receptor and reacts only with cells transfected with the 'long' DNA subtype and not with those transfected with the 'short' DNA subtype. This recognition is specific and can be inhibited by the corresponding free peptide and not by a non-relevant peptide.