K+] dependence of open-channel conductance in cloned inward rectifier potassium channels (IRK1, Kir2.1)

Potassium conduction through unblocked inwardly rectifying (IRK1, Kir2.1) potassium channels was measured in inside-out-patches from Xenopus oocytes, after removal of polyamine-induced strong inward rectification. Unblocked IRK1 channel current-voltage (I-V) relations show very mild inward rectification in symmetrical solutions, are linearized in nonsymmetrical solutions that bring the K+ reversal potential to extreme negative values, and follow Goldman-Hodgkin-Katz constant field equation at extreme positive E alpha. When intracellular K+ concentration (KIN) was varied, at constant extracellular K+ concentration (KOUT) the conductance at the reversal potential (GREV) followed closely the predictions of the Goldman-Hodgkin-Katz constant field equation at low concentrations and saturated sharply at concentrations of > 150 mM. Similarly, when KOUT was varied, at constant KIN, GREV saturated at concentrations of > 150 mM. A square-root dependence of conductance on KOUT is a well-known property of inward rectifier potassium channels and is a property of the open channel. A nonsymmetrical two-site three-barrier model can qualitatively explain both the I-V relations and the [K+] dependence of conductance of open IRK1 (Kir2.1) channels.     

Effect of dietary restriction on benzo[a]pyrene (BaP) metabolic activation and pulmonary BaP-DNA adduct formation in mouse

Hepatic microsomal xenobiotic metabolizing enzyme activities of laboratory animals can be modulated by Dietary restriction (DR). The modulation of xenobiotic metabolizing enzyme activities can affect the metabolic activation of chemical carcinogens. Acute DR (60% of the food consumption of ad libitum (AL)-fed mice for 7 weeks) reduced the body weights of the male B6C3F1 mice, and increased mouse pulmonary cytochrome P4501A1-dependent BaP metabolizing enzyme activity. The effects of DR on the formation of the specific BaP-DNA adduct, 10-(N2-deoxyguanosinyl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-BaP (BaP-N2-dG) in mouse lung can be detected by using 32P-postlabeling technique. In both AL- and DR-mice total BaP-DNA adduct formation in lung reached a peak at 48 hours after treatment with [3H]BaP and the in vivo formation of BaP-N2-dG was greater in DR mouse lung than in that of AL-animals by 22%. DR increased in vitro BaP-N2-dG formation by 39% when calf-thymus DNA was incubated with BaP using liver microsomes obtained from DR- or AL-mice as the enzyme source. The formation of the specific BaP-N2-dG adducts, measured by 32P-postlabeling, was only 20% of the total [3H]BaP-DNA adducts as determined by liquid scintillation counting. The increase of BaP-DNA adduct formation in mouse lung was correlated to the enhancement of the mouse pulmonary BaP metabolizing enzyme activity. Our results indicated that the effect of DR on the metabolic activation of BaP in mouse lung was dependent upon the mouse lung cytochrome P4501A1-dependent BaP metabolizing enzymes activities which was significantly increased by DR.     

Characterization and sequence of the Escherichia coli panBCD gene cluster

A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of asparate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by orf3, which is oriented in the opposite direction. Interruptions in the remaining open reading frames did not affect growth on glucose-minimal medium. No significant similarity to sequences in databases was found for orf1 and orf2. Orf3 contained extensive similarity to reading frames defined by E. coli yjiP, yjiQ, yhgA, and yafD. The function of these amino acid sequences is as yet undefined.     

Meta-analytic evaluation of skills training research for individuals with severe mental illness.

A meta-analysis of 68 studies examined the effectiveness of skills training for individuals with severe mental illness and the influence of such factors as methodological rigor, choice of outcome measures, and service settings. The methodological quality of these studies was generally very good. Skills training was found to be moderately to strongly effective in increasing skill acquisition and reducing psychiatric symptoms. However, effect size varied by type of outcome measure, with situationally specific measures yielding larger effects than measures of skill usage and role functioning. Studies rarely examined whether acquired skills were used outside the training setting. Surprisingly, most studies were confined to inpatient settings, and most focused exclusively on social skills. Implications are discussed for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metastatic malignant melanoma: an unusual case presentation

Secondary involvement of the genitourinary tract with malignant melanoma is a common autopsy finding, but rarely evident clinically. We report a rare case involving a previously asymptomatic patient presenting with gross hematuria and a large renal mass, which was found to be metastatic melanoma. We propose that metastatic melanoma to the kidney, although rare, be considered in the differential diagnosis of disease processes causing hematuria.     

Coenzyme Q10 and adriamycin toxicity in mice

Pretreatment for four days with coenzyme Q10 (CoQ10) significantly lowered the acute toxicity in female C3H/HeNCrlBR mice given moderately lethal (15.0 and 20.0 mg/kg) i.p. doses of adriamycin as well as in male ICR/Hla mice given 12.5 mg/kg i.p. adriamycin. In both strains of mice, CoQ10 pretreatment did not protect the mice at higher i.p. adriamycin dose levels. When adriamycin was administered by the clinically-used i.v. route, CoQ10 pretreatment did not reduce acute toxicity at moderately lethal doses in either strain. At higher i.v. adriamycin dose levels, CoQ10 pretreatment significantly enhanced acute toxicity. CoQ10 pretreatment did not alter the antitumor effectiveness of adriamycin (i.p. or i.v.) against the Dunn osteosarcoma.     

Groupness and adherence in structured exercise settings.

This study examined the relationship between groupness and self-reported exercise adherence. Exercise participants (N = 86) recalled a structured setting where they had been active with others during the last six months. To capture groupness, five group variables (i.e., common fate, mutual benefit, social structure, group processes, and self-categorization) were assessed. Indicators of self-reported adherence were participant's recall of frequency (times/month) and percent attendance in a specified structured exercise setting. Results from structural equation modeling revealed an acceptable fit: χ2 = 18.89, p > .05, Root Mean Square Error of Approximation (RMSEA) = 0.075, Comparative Fit Index (CFI) = 0.95 for the hypothesized model. Groupness was positively related to self-reported adherence explaining 20% of the variance in adherence. These findings provide preliminary support for the idea that perceiving a collection of exercise participants as being more like a group may be associated with adherence in a structured exercise setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

More than biofuels – Potential uses of microalgae as sources of high‐value lipids

Cultivation of microalgae has potential in producing a feedstock for biofuels and, in addition, high‐value lipid bioproducts such as long‐chain (⪈C₂₀, LC) omega‐3 oils, carotenoid pigments and squalene, as well as other non‐lipid materials including exopolysaccharide. The high‐value LC omega‐3 oils have been conventionally sourced from fish. This paper provides a perspective on our recent study of the heterotrophic growth of thraustochytrids for their wider biotechnological potential, including as a source of a range of higher value lipids in addition to biofuels.