Crustal processes sustain Arctic abiotic gas hydrate and fluid flow systems.

The Svyatogor Ridge and surroundings, located on the sediment-covered western flank of the Northern Knipovich Ridge, host extensive gas hydrate and related fluid flow systems. The fluid flow system here manifests in the upper sedimentary sequence as gas hydrates and free gas, indicated by bottom simulating reflections (BSRs) and amplitude anomalies. Using 2D seismic lines and bathymetric data, we map tectonic features such as faults, crustal highs, and indicators of fluid flow processes. Results indicate a strong correlation between crustal faults, crustal highs and fluid accumulations in the overlying sediments, as well as an increase in geothermal gradient over crustal faults. We conclude here that gas generated during the serpentinization of exhumed mantle rocks drive the extensive occurrence of gas hydrate and fluid flow systems in the region and transform faults act as an additional major pathway for fluid circulation.

Short stay and less pain after ambulatory anterior cruciate ligament (ACL) repair: COX-2 inhibitor versus glucocorticoid versus both combined.

BACKGROUND: Many studies have demonstrated that either COX-2 antagonists or glucocorticoids are efficient analgesics after orthopaedic surgery. We wanted to evaluate if the combination of these two drugs was better than one drug alone when added to paracetamol, local anaesthesia, and cryo-cuff for outpatient anterior crucial ligament (ACL) surgery. METHODS: In a double-blind design, 89 adult patients scheduled for day-case ACL repair in general anaesthesia were randomly assigned into three groups: The COXIB group (n = 30) received either 40 mg parecoxib iv or 120 mg etoricoxib orally 1 h before surgery. The STEROID group (n = 30) received 8 mg dexamethasone iv, and the combination group (Group COMBI, n = 29) received both. RESULTS: At 24 h, Group COMBI had significantly lower visual analogue scale (0-10 cm) scores during rest (2.1 ± 1.3) (mean ± standard deviation) and movement (4.2 ± 2.5) when compared to both the COXIB group (P = 0.04) and the STEROID group (P = 0.035). The accumulated consumption of rescue opioids (5.2 ± 4,5 mg morphine) was also significantly lower at 24 h compared to the other groups (P = 0.02). Mean time to discharge from hospital was about 3 h in all groups. The pain scores in the post-anaesthetic care unit, mobilization at 24 h and 7 days, and general level of satisfaction were similar between the groups. CONCLUSION: The combination of a COX-2 inhibitor and dexamethasone results in better pain relief 24 h after surgery in patients undergoing outpatient ACL surgery, compared to COX-2 inhibitor alone or dexamethasone alone. With a dedicated multimodal pain regime, most ACL patients may be discharged within 3 h.

Analysis of the role of calmodulin binding and sequestration in neuromodulin (GAP-43) function.

We demonstrated previously that forced expression of the neuronal phosphoprotein neuromodulin (also known as GAP-43, F1, B-50, and p57) in mouse anterior pituitary AtT-20 cells enhances depolarization-mediated secretion and alters cellular morphology. Here we analyze the role of calmodulin binding by neuromodulin in these responses. In cells expressing wild-type neuromodulin, a complex with calmodulin that is sensitive to intracellular calcium and phosphorylation is localized to the plasma membrane. Transfection of several mutant forms of neuromodulin shows that the effects of this protein on secretion are dependent on both calmodulin binding and association with the plasma membrane. In contrast, the morphological changes depend only on membrane association. Thus, the multitude of effects of neuromodulin noted in previous studies may result from divergent properties of this protein.

Growth-associated protein-43 (GAP-43) facilitates peptide hormone secretion in mouse anterior pituitary AtT-20 cells.

The neuronal growth-associated protein (GAP)-43 (neuromodulin, B-50, F1), which is concentrated in the growth cones of elongating axons during neuronal development and in nerve terminals in restricted regions of the adult nervous system, has been implicated in the release of neurotransmitter. To study the role of GAP-43 in evoked secretion, we transfected mouse anterior pituitary AtT-20 cells with the rat GAP-43 cDNA and derived stably transfected cell lines. Depolarization-mediated beta-endorphin secretion was greatly enhanced in the GAP-43-expressing AtT-20 cells without a significant change in Ca2+ influx; in contrast, expression of GAP-43 did not alter corticotropin-releasing factor-evoked hormone secretion. The transfected cells also displayed a flattened morphology and extended processes when plated on laminin-coated substrates. These results suggest that AtT-20 cells are a useful model system for further investigations on the precise biological function(s) of GAP-43.