Angling-induced cardiac disturbance of free-swimming largemouth bass (Micropterus salmoides) monitored with heart rate telemetry

The sub‐lethal effects of catch‐and‐release angling have been poorly studied because of the difficulties in monitoring physiological parameters in free‐swimming fish. Laboratory studies provide the opportunity to examine sub‐lethal effects in controlled environments, but do not incorporate site‐specific characteristics. In this study we angled free‐swimming largemouth bass (Micropterus salmoides) equipped with heart rate transmitters to exhaustion using rod and reel, and exposed fish to air for 30 s. Experiments were repeated at four water temperatures (13, 17, 21, and 25°C). These field data were compared with published findings from largemouth bass collected at the same water temperatures in a controlled laboratory setting using Doppler flow probes. Field collected heart rate data increased with increasing water temperatures (Q₁₀ values 1.30–1.37). Pre‐disturbance heart rates were ～30% higher for free‐swimming fish in the field than previously collected laboratory data at the same water temperatures. Fish angled in the field exhausted ～40% more rapidly than fish chased in the laboratory. Maximal heart rate was ～15% higher for free‐swimming fish in the field than for data collected from laboratory restrained fish, but scope for heart rate was reduced by up to 20% in the field, especially at higher water temperatures. Heart rate in free‐swimming fish was highly variable at all times, obscuring clear recovery patterns. Conversely, laboratory cardiac parameters exhibited less variable patterns, peaking clearly following disturbances and recovering in about 135 min, independent of water temperature. Based upon these findings, we suggest that comprehensive studies incorporating both laboratory and field experiments are needed for truly understanding the effect of catch‐and‐release angling on fish.     

Neurite Fasciculation Mediated by Complexes of Axonin-1 and Ng Cell Adhesion Molecule

Neural cell adhesion molecules composed of immunoglobulin and fibronectin type III-like domains have been implicated in cell adhesion, neurite outgrowth, and fasciculation. Axonin-1 and Ng cell adhesion molecule (NgCAM), two molecules with predominantly axonal expression exhibit homophilic interactions across the extracellular space (axonin- 1/axonin-1 and NgCAM/NgCAM) and a heterophilic interaction (axonin-1–NgCAM) that occurs exclusively in the plane of the same membrane (cis-interaction). Using domain deletion mutants we localized the NgCAM homophilic binding in the Ig domains 1-4 whereas heterophilic binding to axonin-1 was localized in the Ig domains 2-4 and the third FnIII domain. The NgCAM–NgCAM interaction could be established simultaneously with the axonin-1–NgCAM interaction. In contrast, the axonin-1–NgCAM interaction excluded axonin-1/axonin-1 binding. These results and the examination of the coclustering of axonin-1 and NgCAM at cell contacts, suggest that intercellular contact is mediated by a symmetric axonin-1₂/NgCAM₂ tetramer, in which homophilic NgCAM binding across the extracellular space occurs simultaneously with a cis-heterophilic interaction of axonin-1 and NgCAM. The enhanced neurite fasciculation after overexpression of NgCAM by adenoviral vectors indicates that NgCAM is the limiting component for the formation of the axonin-1₂/NgCAM₂ complexes and, thus, neurite fasciculation in DRG neurons.     

Irreversible Electroporation of Malignant Hepatic Tumors - Alterations in Venous Structures at Subacute Follow-Up and Evolution at Mid-Term Follow-Up

Purpose

To evaluate risk factors associated with alterations in venous structures adjacent to an ablation zone after percutaneous irreversible electroporation (IRE) of hepatic malignancies at subacute follow-up (1 to 3 days after IRE) and to describe evolution of these alterations at mid-term follow-up.

Materials and Methods

43 patients (men/women, 32/11; mean age, 60.3 years) were identified in whom venous structures were located within a perimeter of 1.0 cm of the ablation zone at subacute follow-up after IRE of 84 hepatic lesions (primary/secondary hepatic tumors, 31/53). These vessels were retrospectively evaluated by means of pre-interventional and post-interventional contrast-enhanced magnetic resonance imaging or computed tomography or both. Any vascular changes in flow, patency, and diameter were documented. Correlations between vascular change (yes/no) and characteristics of patients, lesions, and ablation procedures were assessed by generalized linear models.

Results

191 venous structures were located within a perimeter of 1.0 cm of the ablation zone: 55 (29%) were encased by the ablation zone, 78 (41%) abutted the ablation zone, and 58 (30%) were located between 0.1 and 1.0 cm from the border of the ablation zone. At subacute follow-up, vascular changes were found in 19 of the 191 vessels (9.9%), with partial portal vein thrombosis in 2, complete portal vein thrombosis in 3, and lumen narrowing in 14 of 19. At follow-up of patients with subacute vessel alterations (mean, 5.7 months; range, 0 to 14 months) thrombosis had resolved in 2 of 5 cases; vessel narrowing had completely resolved in 8 of 14 cases, and partly resolved in 1 of 14 cases. The encasement of a vessel by ablation zone (OR = 6.36, p<0.001), ablation zone being adjacent to a portal vein (OR = 8.94, p<0.001), and the usage of more than 3 IRE probes (OR = 3.60, p = 0.035) were independently associated with post-IRE vessel alterations.

Conclusion

Venous structures located in close proximity to an IRE ablation zone remain largely unaffected by this procedure, and thrombosis is rare.     

MKR mice are resistant to the metabolic actions of both insulin and adiponectin: discordance between insulin resistance and adiponectin responsiveness

Most rodent models of insulin resistance are accompanied by decreased circulating adiponectin levels. Adiponectin treatment improves the metabolic phenotype by increasing fatty acid oxidation in skeletal muscle and suppressing hepatic glucose production. Muscle IGF-I receptor (IGF-IR)-lysine-arginine (MKR) mice expressing dominant-negative mutant IGF-IRs in skeletal muscle are diabetic with insulin resistance in muscle, liver, and adipose tissue. Adiponectin levels are elevated in MKR mice, suggesting an unusual discordance between insulin resistance and adiponectin responsiveness. Therefore, we investigated the metabolic actions of adiponectin in MKR mice. MKR and ob/ob mice were treated both acutely (28 microg/g) and chronically (for 2 wk) with full-length adiponectin. Acute hypoglycemic effects of adiponectin were evident only in ob/ob mice but not in MKR mice. Chronic adiponectin treatment significantly improved both insulin sensitivity and glucose tolerance in ob/ob but not in MKR mice. Adiponectin receptor mRNA levels and adiponectin-stimulated phosphorylation of AMPK in skeletal muscle and liver were similar among MKR, wild-type, and ob/ob mice. Thus MKR mice are adiponectin resistant despite normal expression of adiponectin receptors and normal AMPK phosphorylation in muscle and liver. MKR mice may be a useful model for dissecting relationships between insulin resistance and adiponectin action in regulation of glucose homeostasis.     

Selective inhibition of FLICE-like inhibitory protein expression with small interfering RNA oligonucleotides is sufficient to sensitize tumor cells for TRAIL-induced apoptosis

BACKGROUND: Most tumors express death receptors and their activation represents a potential selective approach in cancer treatment. The most promising candidate for tumor selective death receptor-activation is tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo2L, which activates the death receptors TRAIL-R1 and TRAIL-R2, and induces apoptosis preferentially in tumor cells but not in normal tissues. However, many cancer cells are not or only moderately sensitive towards TRAIL and require cotreatment with irradiation or chemotherapy to yield a therapeutically reasonable apoptotic response. Because chemotherapy can have a broad range of unwanted side effects, more specific means for sensitizing tumor cells for TRAIL are desirable. The expression of the cellular FLICE-like inhibitory protein (cFLIP) is regarded as a major cause of TRAIL resistance. We therefore analyzed the usefulness of targeting FLIP to sensitize tumor cells for TRAIL-induced apoptosis. MATERIALS AND METHODS: To selectively interfere with expression of cFLIP short double-stranded RNA oligonucleotides (small interfering RNAs [siRNAs]) were introduced in the human cell lines SV80 and KB by electroporation. Effects of siRNA on FLIP expression were analyzed by Western blotting and RNase protection assay and correlated with TRAIL sensitivity upon stimulation with recombinant soluble TRAIL and TRAIL-R1- and TRAIL-R2-specific agonistic antibodies. RESULTS: FLIP expression can be inhibited by RNA interference using siRNAs, evident from reduced levels of FLIP-mRNA and FLIP protein. Inhibition of cFLIP expression sensitizes cells for apoptosis induction by TRAIL and other death ligands. In accordance with the presumed function of FLIP as an inhibitor of death receptor-induced caspase-8 activation, down-regulation of FLIP by siRNAs enhanced TRAIL-induced caspase-8 activation. CONCLUSION: Inhibition of FLIP expression was sufficient to sensitize tumor cells for TRAIL-induced apoptosis. The combination of TRAIL and FLIP-targeting siRNA could therefore be a useful strategy to attack cancer cells, which are resistant to TRAIL alone.     

DNA indels in coding regions reveal selective constraints on protein evolution in the human lineage

Background  

Insertions and deletions of DNA segments (indels) are together with substitutions the major mutational processes that generate genetic variation. Here we focus on recent DNA insertions and deletions in protein coding regions of the human genome to investigate selective constraints on indels in protein evolution.     

Adults' awareness of faces follows newborns' looking preferences

From the first days of life, humans preferentially orient towards upright faces, likely reflecting innate subcortical mechanisms. Here, we show that binocular rivalry can reveal face detection mechanisms in adults that are surprisingly similar to inborn face detection mechanism. We used continuous flash suppression (CFS), a variant of binocular rivalry, to render stimuli invisible at the beginning of each trial and measured the time upright and inverted stimuli needed to overcome such interocular suppression. Critically, specific stimulus properties previously shown to modulate looking preferences in neonates similarly modulated adults' awareness of faces presented during CFS. First, the advantage of upright faces in overcoming CFS was strongly modulated by contrast polarity and direction of illumination. Second, schematic patterns consisting of three dark blobs were suppressed for shorter durations when the arrangement of these blobs respected the face-like configuration of the eyes and the mouth, and this effect was modulated by contrast polarity. No such effects were obtained in a binocular control experiment not involving CFS, suggesting a crucial role for face-sensitive mechanisms operating outside of conscious awareness. These findings indicate that visual awareness of faces in adults is governed by perceptual mechanisms that are sensitive to similar stimulus properties as those modulating newborns' face preferences.     

Protease inhibitors interfere with the transforming growth factor-beta-dependent but not the transforming growth factor-beta-independent pathway of tumor cell-mediated immunosuppression.

Tumor cells have been reported to exert inhibitory effects on the activation of T lymphocytes in vitro. We show that the IL-2-stimulated proliferation of a Th cell line is suppressed when the T cells are cocultured with human glioblastoma and melanoma cell lines. The use of two Th cell clones that differ in their responsiveness to growth-inhibition by transforming growth factor-beta (TGF-beta) and the analysis of tumor cell-derived supernatants as well as of TGF-beta 1/TGF-beta 2 gene expression allowed to distinguish two pathways of tumor-induced immunosuppression. Glioblastoma cells exert their immunosuppressive effects by producing biologically active TGF-beta 2, whereas the immunosuppressive state induced by melanoma cells is TGF-beta-independent and requires direct contact between tumor cell and T cell. The TGF-beta-dependent immunosuppression is down-regulated by various protease inhibitors and up-regulated by estradiol via modulation of the production of biologically active TGF-beta 2 by glioblastoma cells leaving total activatable TGF-beta 2 unaffected. No such modulation is functional for the TGF-beta-independent pathway of immunosuppression. We conclude that the production of active TGF-beta by tumor cells is regulated at a posttranslational level by the coordinated action of several proteolytic enzymes.     

Levels of duplicate gene expression in armoured catfishes

Species of armoured catfishes differ significantly in their cellular DNA content and chromosome number. Starch gel electrophoresis of isozymes was used to determine whether each of 16 enzyme loci was expressed in a single or duplicate state. The percent of enzyme loci exhibiting duplicate locus expression in Corydoras aeneus, Corydoras julii, Corydoras melanistius, and Corydoras myersi was 37.5 percent, 18.75 percent, 12.5 percent, and 6.25 percent, respectively. The percentage of loci expressed in duplicate is higher in the species with higher haploid DNA contents, which are 4.4 pg, 3.0 pg, and 2.3 pg, respectively. These differences in DNA contents are also associated with differences in chromosome number. These data are consistent with the hypothesis that increases in DNA contents and enzyme loci occur both by tetraploidization and by regional gene duplication and that these increases are then followed by a partial loss of DNA and a reduction in the number of the duplicate isozyme loci expressed. Such analyses provide insight into the mechanisms of genome amplification and reduction as well as insights into the fats of duplicate genes.