Blends of alkyloxy-substituted liquid-crystalline aromatic polyesters and copolyesters with poly(ethylene terephthalate)

Blends containing poly(ethylene terephthalate) (PET) and a series of alkyloxy laterally substituted liquid-crystalline copolyesters (HTO5-X series 1 ) in various ratios were prepared in the melt at 260°C by mechanical mixing. The visual and light microscopical appearance of the blends in the solid state and in the melt was found to be homogeneous for those blends which contained an aliphatic-rich HT05-X copolyester. The homogeneous appearance can be explained by a colloidal dispersion of the liquid-crystalline polymer (LCP) in PET. Obvious phase separation in the melt occurs slowly after long periods of time. Phase separation is forced by annealing at about 270°C, where a change of viscosity is observed, and by shearing the sample. Characterization of theblends by DSC experiments shows that the thermal behaviour of all blends is dominated by the phase transitions of PET and that the LC-low-phase of the HTO5-X copolyesters with a high degree of alkyloxy substitution is suppressed. The WAXS diffraction patterns of all blends contained an amorphous halo. For blends with low HTO5-X concentration, inner reflexions from the nematic sanidic phase, as exhibited by the HTO5-X copolyester, could be observed. For blends with higher HTO5-X copolyester concentration, characteristic reflexions from HTO5-X copolyester crystals could be observed. The number of X-ray reflexions of the crystalline LCP in the blend is reduced compared to that of the pure LCP.     

Heart-focused anxiety,illness beliefs,and behavioral impairment: Comparing healthy heart-anxious patients with cardiac and surgical inpatients

Psychological features and complaints of persons presenting to medical settings with heart-focused anxiety and noncardiac chest pain are poorly understood. Comparing 20 healthy heart-anxious patients to cardiac and surgical inpatients and nonpatient controls, we found that healthy heart-anxious patients (a) were as afraid of chest pain and heart palpitations as inpatients with heart disease, (b) were as incapacitated by symptoms and using medical services as much as both inpatient groups; and (c) reported higher levels of cardiac disease conviction, heart awareness, and behaviors designed to protect their heart than surgical patients and nonpatients. Compared to all other groups, healthy heart-anxious patients reported more panic and other anxiety disorders, hypochondriacal beliefs, physical symptoms, obsessive-compulsive concerns, and negative affect. Following a hyperventilation test, heart-anxious patients also indicated more distressing symptoms and thoughts, and felt less safe and in control than surgical patients and nonpatients. Results support efforts for a timely recognition, diagnosis, and behavioral treatment of persons with heart-focused anxiety.     

Immunolocalization of lamins and nuclear pore complex proteins by atomic force microscopy

The nuclear envelope functions as a selective barrier separating the nuclear from the cytosolic compartment. Nuclear pore complexes (NPCs) mediate nuclear import and export of macromolecules and, therefore, are potential regulators of gene expression. In this study we applied atomic force microscopy (AFM) to visualize the three dimensional (3D) structure of individual NPCs in the absence and presence of two different antibodies, one directed against a pore protein (gp62) and another directed against Xenopus lamin LIII, a component of the nuclear lamina, a filament meshwork localized on the nucleoplasmic side of the nuclear envelope (NE) adjacent to and interacting with NPCs. Using 12-nm gold-labelled secondary antibodies and transmission electron microscopy we could clearly localize the primary single anti-gp62 antibody on NPCs and the primary single anti-LIII antibody between NPCs. Using AFM, the secondary antibodies against anti-gp62 could be detected as particles 7 nm in height on the nucleoplasmic face of NPCs. The secondary antibodies against anti-LIII could be clearly identified between NPCs. The secondary antibodies, attached to a 12-nm colloidal gold particle and visualized on glass, revealed similar shapes and heights as found on NEs. According to the 3D images, the volume of a single gold particle conjugated with secondary antibodies was 10 203 nm³. This volume is equivalent to the volume of 38 IgG molecules associated with one individual gold particle. A similar volume of 11 987 nm³ was calculated from a model assuming that the 150-kDa IgG molecules perfectly cover the spherical gold particle. We conclude that AFM can be used for identifying antibodies or other macromolecules associated with biomembranes.     

Microglial Reaction in the Rat Cerebral Cortex Induced by Cortical Spreading Depression

The response of microglial cells to cortical spreading depression (CSD) was studied in rat brain by immunocytochemistry. CSD was elicited for one hour by the topical application of 4M potassium chloride solution and the microglial reaction examined immunocytochemically after 4, 16, 24 and 72 hours. CSD was sufficient to induce a microglial reaction throughout the cortex at 24 hours. Activated microglial cells furthermore showed a striking de-novo expression of major histocompatibility complex class II antigens. In contrast, no microglial reaction was observed in the cortex of sham-operated animals. This microglial reaction in response to CSD was not associated with histologically detectable neuronal damage. These results support the view that microglial cells are extremely sensitive to changes of the brain microenvironment. Their activation may be related to changes of ion homeostasis in the brain which are not sufficient to trigger neuronal injury.     

Pattern of time-dependent reduction of histologically determined infarct volume after focal ischaemia in mice

The mouse model of transcranial permanent occlusion of the middle cerebral artery (tpMCAO) is widely used in stroke research. Here we quantified infarct size using a conventional histological method at several post-ischaemic times, going beyond the commonly analysed period of up to 2 days, following artery occlusion. Two different mouse strains, which are widely used for pharmacological studies of neuroprotection and for genetic engineering, were used. A drill whole was made into the skull of anaesthetised mice and ischaemia was induced by electrocoagulation of the middle cerebral artery. In both mouse strains tested (C57Black/6 and NMRI), the measured infarct volumes decreased significantly during the first days after tpMCAO. Notably, 13 days after surgery, ischaemic and sham-operated animals had indistinguishably small lesions, which where in the range of only 5% of the infarct size on day 2 post-ischaemia. The standard method of calculating oedema and shrinkage correction provided no sufficient explanation for this significant decrease in infarct volume. There was, however, evidence that structural changes in the residual ipsilateral hemisphere may compromise the significance of results arising from the method of calculating oedema and shrinkage correction. In conclusion, our study indicates that the pronounced and fast, time-dependent decrease in histologically defined infarct volume can compromise results when studying the lasting neuroprotective effects of potential drugs.     

Der gitterfaktor des gaußschen parakristalls

By using so-called “characteristics”, the long-range distortion in Gaussian paracrystals may be described in a way which is independent of the lattice, provided distance and directional fluctuations between neighbouring lattice points are used. By a two-fold Fourier transform — similar to the approach of Warren and Averbach — the lattice factor, describing the interference effect of the Gaussian paracrystal, is found from the convolution of an ideal reciprocal lattice with a lattice-independent profile function. Threadlike “one-dimensional” Gaussian and ideal paracrystals are identical with each other. Making use of the two-fold Fourier transform, Hosemann's K-factor splits into isolated discs (“Scheibchen”) showing Lorentzian profiles. The profile function of two-and three-dimensional Gaussian paracrystals shows a Lorentzian-2/3 or a Lorentzian-2 profile, respectively. The different profiles are experimentally distinguishable when using a position-sensitive detector. Thus, based on experimental results, paracrystalline lattice distortions with Gaussian characteristics are detectable.     

Scalp topography of the spontaneous K-complex and of delta-waves in human sleep

Objective: Together with spindles, K-complexes are well known hallmarks of stage 2 sleep (S2). However, little is known about their topographical distribution in comparison to delta-waves and to K-complexes superimposed by spindles. Patients and methods: In this study, the topographical distribution of spontaneous K-complexes and delta-waves in S2 and delta-waves in stage 4 sleep (S4) in 10 healthy young adults (aged 20 to 35 years, 7 female) was investigated. K-complexes with and without spindles in S2, delta-waves with and without spindles in S2, and delta-waves in S4 distributed all over the night were visually selected. EEG power maps and statistical parametric maps were calculated. Results: Absolute delta power of S2 K-complexes appeared to be significantly higher than of S2 delta-waves and delta power of S4 delta-waves was higher than of S2 delta-waves. In K-complexes and delta-waves, power was found to be highest over medio-frontal regions in the delta frequency band (0.5 - 4.0 Hz) with a second maximum occipitally in delta-waves, no matter whether superimposed by a spindle or not. Conclusion: K-complexes and delta-waves in S2 differ in topographical distribution. Even though in S2 delta-waves have less power, they have a similar topographical distribution in S2 and S4, supporting the hypothesis that delta-waves in S2 further develop towards delta-waves in slow wave sleep. The delta frequency components of K-complexes and delta-waves are unaffected by spindles.     

Oxidative polymerization of 2,6-dimethylphenol with semiconducting organic polymeric metal complexes containing the bis(ethylene-1,2-dithiolato)copper (II) structure, 1

In the oxidative polymerization of 2,6-dimethylphenol ( 8 ) the catalytic activities of the following semiconducting organic polymeric metal complexes were studied: polymeric complexes containing bis(ethylene-1,2-dithiolato)Cu(II) or Fe(III) complexes and copper(II) phthalocyanine structures ( 3a – c ), catalysts consisting of bis(ethylene-1,2-dithiolato)-Cu(II) or Fe(III) complex structures and hemiporphyrazine type structures ( 5a – c ), and also polymers containing a copper complex of dimercaptomaleic acid monoamide ( 7 ). It was found that a suspension of the insoluble bis(ethylene-1,2-dithiolato)Cu(II) polymeric complexes of type 3 catalyzes the polymerization in the presence of oxygen in pyridine at room temperature producing poly[oxy-(2,6-dimethyl-1,4-phenylene)] ( 9 ) in very good yields. Polymeric complexes of type 5 were inactive by themselves. However, we showed that bis(ethylene-1,2-dithiolato)Cu(II) polymeric complexes of both the 3 and 5 type possess great activities if they are used in the presence of small amounts of copper(II)-pyridine complex in pyridine solution (the chosen concentration was so low that the Cu(II)-pyridine complex alone had only a small activity). Bis(ethylene-1,2-dithiolato)Fe(III) complexes of both the 3 and 5 type were inactive even in the presence of the Cu(II)-pyridine complex.     

Evaluation of two chromogenic agar media for recovery and identification of Staphylococcus aureus small-colony variants

To identify the most rapid and reliable technique for recovery and identification of Staphylococcus aureus small-colony variants (SCVs), the colonial appearance of 106 isolates representing SCVs and the normal phenotype were evaluated on two newly described chromogenic agar media. Although almost all of the SCVs grew on the chromogenic agar media, they did not exhibit a change of color. In comparison with conventional media, S. aureus ID agar (SAID; bioMerieux, La Balme Les Grottes, France) showed the most reliable results, with 49 of 53 SCVs tested growing either as an SCV colony or with a normal phenotype after only 24 h of incubation. Growth of SCVs was often not detected before 72 h of incubation on some of the media tested. In conclusion, the most accurate and rapid method to detect both the species S. aureus and the SCV phenotype is to inoculate specimens onto both Columbia blood agar and SAID.     

The developmentally regulated neural crest-associated glycotope HNK-1 predicts metastasis in cutaneous malignant melanoma

Aberrant glycosylation is a common feature of metastatic sub-clones of malignant tumours and in uveal melanoma in particular, the HNK-1 glycotope has been positively correlated with poor prognosis. So far, no such correlation has been investigated in cutaneous melanoma. In order to do so, HNK-1 expression was evaluated immunohistochemically in 100 primary cutaneous melanomas and correlated with metastasis after up to 10-years' follow-up. Furthermore, HNK-1 expression was analysed in metastatic deposits (19 distant cutaneous metastases and six sentinel lymph node metastases), as well as in benign nevi. Kaplan-Meier analysis revealed a positive association between HNK-1 expression and metastasis (p < 0.005) and multivariate Cox regression analysis adjusted for the standard prognostic markers ulceration and vertical tumour thickness confirmed HNK-1 expression as an independent prognostic marker. HNK-1 expression was preserved in 42% of the distant cutaneous metastases, but metastatic cells in lymph nodes were devoid of HNK-1 immunoreactivity. None of the benign pigmented lesions exhibited HNK-1 immunoreactivity. Expression of the HNK-1 glycotope in cutaneous malignant melanoma is an independent prognostic marker of metastasis. Differential HNK-1 expression at the metastatic sites implies that its expression is modulated by the surrounding environment. As HNK-1 is also transiently expressed during migration of melanocyte precursor cells derived from the neural crest, recapitulation of this transient expression might occur during metastatic spread of cutaneous malignant melanoma.