Antagonism of levcromakalim by imidazoline- and guanidine-derivatives in rat portal vein: involvement of the delayed rectifier

1. In rat whole portal veins, guanabenz (100 nM to 10 microM) and antazoline (100 nM to 100 microM) each increased the amplitude, frequency and duration of spontaneous contractions. In addition, guanabenz (30 microM) and antazoline (30 microM) each antagonized the ability of levcromakalim (3 nM to 10 microM) to inhibit the spontaneous contractions of this tissue. 2. Whole-cell voltage-clamp recordings were made from freshly-isolated rat portal vein cells dispersed by a collagenase/pronase enzyme treatment. The ability of several agents (antazoline, cirazoline, clonidine, guanabenz and phentolamine, each containing an imidazoline or guanidine moiety), to modulate potassium (K) currents and to inhibit the actions of levcromakalim was investigated. 3. Antazoline, cirazoline, clonidine, guanabenz and phentolamine (each at a concentration of 30 microM) had little effect on control non-inactivating currents but inhibited the delayed-rectifier current, IK(V). 4. Levcromakalim (1 microM) induced a non-inactivating current, IK(ATP), and also inhibited the delayed rectifier current, IK(V). 5. Glibenclamide (1 microM) had no effect on control delayed rectifier or non-inactivating currents, but it inhibited the simultaneous induction of IK(ATP) and reduction of IK(V) produced by levcromakalim (1 microM). 6. Antazoline, cirazoline, clonidine and guanabenz (each at a concentration of 30 microM) prevented the induction of IK(ATP) by levcromakalim (1 microM). Phentolamine (30 microM) and clonidine (30 microM) each inhibited the IK(ATP) generated by levcromakalim (1 microM). 7. It is concluded that a variety of agents which possess either an imidazoline (antazoline, cirazoline, clonidine and phentolamine) or a guanidine (guanabenz) moiety within their structure inhibit the delayed rectifier current, IK(V). This action may thus be mediated via a so-called non-adrenoceptor imidazoline binding site. Furthermore, the ability of these ligands to inhibit IK(V) and to antagonize both the induction of IK(ATP) and the vasorelaxation produced by levcromakalim is consistent with the view that the channel (KATP) which underlies IK(ATP) is a voltage-insensitive state of the delayed rectifier K-channel (Kv).     

Robust and secure fractional wavelet image watermarking

This paper presents an efficient fractional wavelet transform (FWT) image watermarking technique based on combining the discrete wavelet transform (DWT) and the fractional Fourier transform (FRFT). In the proposed technique, the host image is wavelet transformed with two resolution levels, and then, the middle frequency sub-bands are FRFT transformed. The watermark is hidden by altering the selected FRFT coefficients of the middle frequency sub-bands of the 2-level DWT-transformed host image. Two pseudo-random noise (PN) sequences are used to modulate the selected FRFT coefficients with the watermark pixels, and inverse transforms are finally applied to get the watermarked image. In watermark extraction, we just need the same two PN sequences used in the embedding process and the watermark size. The correlation factor is used to determine whether the extracted pixel is one or zero. The proposed fractional wavelet transform (FWT) image watermarking method is tested with different image processing attacks and under composite attacks to verify its robustness. Experimental results demonstrated improved robustness and security.     

Bayesian prediction of the jth order statistic with burr distribution and a random sample size

This work is concerned with the Bayesian prediction problem of the j order statistic when the size of the future sample is a random variable and the samples are drawn from a generalized Burr distribution (GBD). A numerical illustration is also given.     

Subscales within the dependency factor of the Depressive Experiences Questionnaire

Recent theoretical formulations differentiate two types of depressive experiences: one focused on interpersonal issues, such as loss, abandonment, and loneliness; the other focused on issues of self-esteem, such as failure, guilt, and lack of self-worth and autonomy. The Depressive Experiences Questionnaire (DEQ; Blatt, D'Afflitti, & Quinlan, 1976, 1979) assesses these two types of depression. Symptom-based measures of depression (i.e., the Beck Depression Inventory, Beck, Rush, Shaw, & Emery, 1979) have highly significant correlations with the DEQ Self-Criticism factor but only marginally significant correlations with the DEQ Dependency (or interpersonal) factor. Through the use of facet theory and Smallest Space Analysis (Guttman, 1982a), two facets were identified within the DEQ Dependency factor that appear to assess two different levels of interpersonal relatedness. One facet, labelled dependence, includes items expressing feelings of helplessness; fears and apprehensions about separation and rejection; and intense, broad-ranging concerns about possible loss unrelated to a particular relationship. The second facet, labelled relatedness, includes items that consider feelings of loss and loneliness in reaction to disruption of a relationship with a particular person. The dependence facet had significantly higher correlations with measures of depression, whereas the relatedness facet had significantly higher correlations with measures of psychological well-being, especially in women. Thus, the DEQ Dependency factor appears to contain two facets that assess interpersonal relatedness at different developmental levels and correlate differentially with measures of depression and of psychological well-being.     

Mapping of a distal form of spinal muscular atrophy with upper limb predominance to chromosome 7p

An autosomal dominant distal form of spinal muscular atrophy mainly affecting the upper limbs with a mean age of onset of 17 years has been identified in a large Bulgarian family. Linkage of the above family to the spinal muscular atrophy type I, II and III locus on chromosome 5 has been excluded. In an attempt to map this disease gene we have analysed individuals of this family, with more than 140 microsatellite polymorphic markers of the human genome. A maximum lod score of 5.99 at theta = 0.007 has been obtained with locus D7S795. We have thus mapped the gene for this hereditary form of distal spinal muscular atrophy to chromosome 7p.     

Ultrastructural aspects of the interaction between Escherichia coli and cultured epithelial cells

Microorganisms from two Escherichia coli serotypes were allowed to interact with cultured epithelial cells and the interaction process was followed from 30 to 360 min. Destruction of the microvilli on the epithelial monolayers as well as of the cells themselves was observed only with 0111:H2 serotype.     

Plasma semicarbazide-sensitive amine oxidase activity is elevated in diabetes mellitus and correlates with glycosylated haemoglobin

1. Semicarbazide-sensitive amine oxidase is a common name for a group of heterogeneous amine oxidases which are present in various mammalian tissues, especially in vascular smooth muscle cells, cartilage and adipose tissue, but also in plasma. 2. Plasma semicarbazide-sensitive amine oxidase activity was elevated in a group of 104 patients with insulin-dependent diabetes mellitus compared with normal control subjects (555 +/- 172 versus 352 +/- 102 m-units/l, P < 0.0005). 3. Plasma semicarbazide-sensitive amine oxidase activity was higher in subgroups with either retinopathy or nephropathy or both [583 +/- 116 (n = 34), 581 +/- 229 (n = 10) and 646 +/- 249 m-units/l (n = 19), respectively] than in the subgroup without overt complications [486 +/- 129 m-units/l (n = 41), P < 0.005]. 4. Plasma semicarbazide-sensitive amine oxidase activity was positively correlated with plasma glycosylated haemoglobin (r = 0.40; P < 0.0001) and with log urinary albumin excretion (r = 0.26; P < 0.025). 5. The possibility that semicarbazide-sensitive amine oxidase, by its conversion of endogenous amines like methylamine and aminoacetone into cytotoxic aldehydes, plays a role in the development of microvascular complications in diabetes mellitus, needs further investigation.