Characterizing SERCA Function in Murine Skeletal Muscles after 35-37 Days of Spaceflight.

It is well established that microgravity exposure causes significant muscle weakness and atrophy via muscle unloading. On Earth, muscle unloading leads to a disproportionate loss in muscle force and size with the loss in muscle force occurring at a faster rate. Although the exact mechanisms are unknown, a role for Ca2+ dysregulation has been suggested. The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump actively brings cytosolic Ca2+ into the SR, eliciting muscle relaxation and maintaining low intracellular Ca2+ ([Ca2+]i). SERCA dysfunction contributes to elevations in [Ca2+]i, leading to cellular damage, and may contribute to the muscle weakness and atrophy observed with spaceflight. Here, we investigated SERCA function, SERCA regulatory protein content, and reactive oxygen/nitrogen species (RONS) protein adduction in murine skeletal muscle after 35-37 days of spaceflight. In male and female soleus muscles, spaceflight led to drastic impairments in Ca2+ uptake despite significant increases in SERCA1a protein content. We attribute this impairment to an increase in RONS production and elevated total protein tyrosine (T) nitration and cysteine (S) nitrosylation. Contrarily, in the tibialis anterior (TA), we observed an enhancement in Ca2+ uptake, which we attribute to a shift towards a faster muscle fiber type (i.e., increased myosin heavy chain IIb and SERCA1a) without elevated total protein T-nitration and S-nitrosylation. Thus, spaceflight affects SERCA function differently between the soleus and TA.

Spatial Scale and Structural Heterogeneity in Skeletal Muscle Performance.

Biological movement is an inherently dynamic process, characterized by large spatiotemporal variations in force and mechanical energy. Molecular level interactions between the contractile proteins actin and myosin do work, generating forces and transmitting them to the environment via the muscle's and supporting tissues' complex structures. Most existing theories of muscle contraction are derived from observations of muscle performance under simple, tightly controlled, in vitro or in situ conditions. These theories provide predictive power that falls off as we examine the more complicated action and movement regimes seen in biological movement. Our early and heavy focus on actin and myosin interactions have lead us to overlook other interactions and sources of force regulation. It increasingly appears that the structural heterogeneity, and micro-to-macro spatial scales of the force transmission pathways that exist between actin and myosin and the environment, determine muscle performance in ways that manifest most clearly under the dynamic conditions occurring during biological movement. Considering these interactions, along with the dynamics of force transmission tissues, actuators, and environmental physics have enriched our understanding of biological motion and force generation. This symposium brings together diverse investigators to consolidate our understanding of the role of spatial scale and structural heterogeneity role in muscle performance, with the hope of updating frameworks for understanding muscle contraction and predicting muscle performance in biological movement.

A brief eHealth tool delivered in primary care to help parents prevent childhood obesity: a randomized controlled trial.

OBJECTIVES: To determine the feasibility and preliminary impact of an electronic health (eHealth) screening, brief intervention and referral to treatment (SBIRT) delivered in primary care to help parents prevent childhood obesity. METHODS: Parents of children (5-17 years) were recruited from a primary care clinic. Children's measured height and weight were entered into the SBIRT on a study-designated tablet. The SBIRT screened for children's weight status, block randomized parents to one of four brief interventions or an eHealth control and provided parents with a menu of optional obesity prevention resources. Feasibility was determined by parents' interest in, and uptake of, the SBIRT. Preliminary impact was based on parents' concern about children's weight status and intention to change lifestyle behaviours post-SBIRT. RESULTS: Parents (n = 226) of children (9.9 ± 3.4 years) were primarily biological mothers (87.6%) and Caucasian (70.4%). The proportion of participants recruited (84.3%) along with parents who selected optional resources within the SBIRT (85.8%) supported feasibility. Secondary outcomes did not vary across groups, but non-Caucasian parents classified as inaccurate estimators of children's weight status reported higher levels of concern and intention to change post-SBIRT. CONCLUSIONS: Our innovative, eHealth SBIRT was feasible in primary care and has the potential to encourage parents of unhealthy weight children towards preventative action.

Predictive and prognostic factors for treatment and survival in 305 patients with advanced gastrointestinal neuroendocrine carcinoma (WHO G3): the NORDIC NEC study.

BACKGROUND: As studies on gastrointestinal neuroendocrine carcinoma (WHO G3) (GI-NEC) are limited, we reviewed clinical data to identify predictive and prognostic markers for advanced GI-NEC patients. PATIENTS AND METHODS: Data from advanced GI-NEC patients diagnosed 2000-2009 were retrospectively registered at 12 Nordic hospitals. RESULTS: The median survival was 11 months in 252 patients given palliative chemotherapy and 1 month in 53 patients receiving best supportive care (BSC) only. The response rate to first-line chemotherapy was 31% and 33% had stable disease. Ki-67<55% was by receiver operating characteristic analysis the best cut-off value concerning correlation to the response rate. Patients with Ki-67<55% had a lower response rate (15% versus 42%, P<0.001), but better survival than patients with Ki-67≥55% (14 versus 10 months, P<0.001). Platinum schedule did not affect the response rate or survival. The most important negative prognostic factors for survival were poor performance status (PS), primary colorectal tumors and elevated platelets or lactate dehydrogenase (LDH) levels. CONCLUSIONS: Advanced GI-NEC patients should be considered for chemotherapy treatment without delay.PS, colorectal primary and elevated platelets and LDH levels were prognostic factors for survival. Patients with Ki-67<55% were less responsive to platinum-based chemotherapy, but had a longer survival. Our data indicate that it may not be correct to consider all GI-NEC as one single disease entity.

Initial experience with single cannulation for venovenous extracorporeal oxygenation in adults.

PURPOSE: Historically, venovenous extracorporeal membrane oxygenation has required dual cannulation. A single-venous cannulation strategy may facilitate implantation and patient mobilization. Here we present our early experience with a single cannulation technique. DESCRIPTION: Review of venovenous extracorporeal membrane oxygenation support using internal jugular vein insertion of the Avalon elite bicaval dual lumen catheter (Avalon Laboratories, Rancho Dominguez, CA) in 11 consecutive patients with severe respiratory failure. EVALUATION: Adequate oxygenation was obtained in all patients: 115 mm Hg PaO(2) (median), 53 to 401 mm Hg (range). Median time of support was 78 hours (range, 3 to 267 hours). No mortality was directly related to the cannulation strategy. There were three nonfatal cannulation-related events. Two patients had proximal cannula displacement requiring repositioning. One patient suffered an acute thrombosis of the cannula. CONCLUSIONS: Our series supports single-venous cannulation in venovenous extracorporeal membrane oxygenation as a promising technique. It may be an excellent alternative to current cannulation strategies in patients requiring prolonged support and specifically for those considered for a bridge-to-lung transplantation.

The care of pin sites with external fixation.

Two protocols for the operative technique and care of the pin-site with external fixation were compared prospectively. There was a total of 120 patients with 46 in group A and 74 in group B. Infection was defined as an episode of pain or inflammation at a pin site, accompanied by a discharge which was either positive on bacterial culture or responded to a course of antibiotics. Patients in group B had a lower proportion of infected pin sites (p = 0.003) and the time to the first episode of infection was longer (p < 0.001). The risk of pin-site infection is lower if attention is paid to avoiding thermal injury and local formation of haematoma during surgery and if after-care includes the use of an alcoholic antiseptic and occlusive pressure dressings.

Low flow after global ischemia to improve postischemic myocardial function and bioenergetics.

OBJECTIVE: In this study, we test the hypothesis that a period of low flow perfusion before full reperfusion improves ventricular function and bioenergetics. DESIGN: Prospective, randomized, controlled animal study. SETTING: Research laboratory. SUBJECTS: Sprague-Dawley rats. INTERVENTIONS: Hearts were perfused with Krebs-Henseleit buffer at 85 mm Hg. The protocol consisted of 10 mins of baseline flow, 15 mins of global ischemia, 5 mins of low flow ischemia, and 30 mins of reperfusion. Groups received 10% or 1% of baseline flow during the low flow period. A control group received 0% low flow (20 mins of global ischemia). MEASUREMENTS AND MAIN RESULTS: Left ventricular function was continuously measured. Hearts were freeze-clamped at various time points, and metabolites were measured. At 10% flow, following global ischemia, both left ventricular function and bioenergetics improved compared with 0% flow and 1% flow. At 1% flow, no changes in function were seen and adenosine 5'-triphosphate concentrations decreased during reperfusion, compared with no flow (9.4 +/- 1.0 vs. 13.2 +/- 1.0 micromol/g of dry weight, p <.01). CONCLUSIONS: Following global ischemia but before full reperfusion, a period of low flow improves postischemic myocardial function and energetic recovery, only if a certain level of low flow is met. Very low flow may further reduce bioenergetic recovery without improvement in postischemic function, compared with continuous global ischemia.

Glucose, insulin and potassium (GIK) during reperfusion mediates improved myocardial bioenergetics.

Previous studies suggest glucose, insulin and potassium (GIK) infusion during ischemia reduces infarct size and improves post-ischemic myocardial function in acute myocardial infarction and following surgical revascularization of the heart. The potential use of GIK when given only during reperfusion after a period of global ischemia, as might occur during cardiac arrest, is unclear. To test the hypothesis that GIK reperfusion improves post-ischemic myocardial bioenergetics and function, we utilized a perfused heart model. Hearts from Sprague-Dawley rats (350-450 g) were perfused at 85 mmHg with oxygenated Krebs-Henseleit bicarbonate containing 5.5 mM glucose and 0.2 mM octanoic acid. Following 20 min of global ischemia, hearts were reperfused for 30 min with original solution (control) or GIK in two different doses (10 or 20 mM glucose each with insulin 10 U/l and K(+) 7 meq/l). Hearts perfused with GIK solutions had significantly higher ATP, creatine phosphate, energy charge, and NADP(+) and lower AMP and inosine levels compared with control after 30 min of reperfusion. Hearts reperfused with GIK had significantly higher developed pressure and higher dP/dt than control reperfused hearts. Reperfusion with GIK improved post-ischemic recovery of both contractile function and the myocardial bioenergetic state. GIK may be a viable adjunctive reperfusion therapy following the global ischemia of cardiac arrest to improve post-resuscitation cardiac dysfunction.

Reactive oxygen species generated during myocardial ischemia enable energetic recovery during reperfusion.

We studied the differences between the functional and bioenergetic effects of antioxidants (AOX) administered before or after myocardial ischemia. Sprague-Dawley rat hearts were perfused with a modified Krebs-Henseleit solution and bubbled with 95% O(2)-5% CO(2). The protocol consisted of 10 min of baseline perfusion, 20 min of global ischemia, and 30 min of reperfusion. An AOX, either 1,2-dihydroxybenzene-3,5-disulfonate (Tiron), a superoxide scavenger, or N-acetyl-L-cysteine, was infused during either baseline or reperfusion. An additional group received deferoxamine as a bolus before ischemia. Hearts were freeze-clamped at baseline, at end of ischemia, and at end of reperfusion for analysis of high-energy phosphates. All AOX, when given before ischemia, inhibited recovery of ATP compared with controls. Both Tiron and deferoxamine also inhibited recovery of phosphocreatine. AOX given before ischemia decreased the efficiency of contraction during reperfusion compared with controls. All of the changes in energetics and efficiency brought on by preischemic AOX treatment could be blocked by a preconditioning stimulus. This suggests that reactive oxygen species, which are generated during ischemia, enhance bioenergetic recovery by increasing the efficiency of contraction.

Postischemic inotropic support of the dysfunctional heart.

OBJECTIVE: To determine relative adenine nucleotide regeneration and improvement in left ventricular (LV) function using three commonly used adrenergic agents--epinephrine, dobutamine, and phenylephrine---during reperfusion after a period of global ischemia. After initial resuscitation from cardiac arrest, adrenergic agents are frequently required to support postischemic LV dysfunction. However, the relative effectiveness and associated bioenergetic changes associated with these agents in the postischemic heart are unclear. DESIGN: Prospective, controlled laboratory study. SETTING: University research laboratory. SUBJECTS: Isolated, perfused Sprague-Dawley rat hearts. INTERVENTIONS: After 20 mins of global ischemia, isolated rat hearts were reperfused for 30 mins with Krebs-Henseleit solution alone (control, n = 8), or with the addition of equipotent doses of epinephrine 1 microM (n = 8), dobutamine 0.3 microM (n = 8), or phenylephrine 50 microM (n = 8). In a second experiment, an alpha-1 antagonist, prazosin was given with phenylephrine to block the presumed alpha-1 agonist effect of phenylephrine. MEASUREMENTS AND MAIN RESULTS: A constant volume balloon was placed in the left ventricle to measure LV pressure and derived parameters of LV function. Adenine nucleotide concentrations were derived at various time points using high-performance liquid chromatography. During reperfusion, the phenylephrine group had significant improvement in LV function and cardiac efficiency in contrast to epinephrine and dobutamine. Total adenine nucleotides tended to be highest in the phenylephrine group with significant increases in adenosine diphosphate and adenosine monophosphate and no significant loss of adenosine triphosphate. The phenylephrine-induced increase in heart rate and developed pressure could be blocked with an alpha-1 antagonist, prazosin. CONCLUSIONS: In the isolated reperfused heart, phenylephrine, mediated by alpha-1 agonism, significantly improves postischemic LV dysfunction without worsening the overall myocardial metabolic state.

Photophysical studies on antimalarial drugs.

Most drugs used in the treatment of malaria produce phototoxic side effects in both the skin and the eye. Cutaneous and ocular effects that may be caused by light include changes in skin pigmentation, corneal opacity, cataract formation and other visual disturbances including irreversible retinal damage (retinopathy) leading to blindness. The mechanism for these reactions in humans is unknown. We irradiated a number of antimalarial drugs (amodiaquine, chloroquine, hydroxychloroquine, mefloquine, primaquine and quinacrine) with light (lambda > 300 nm) and conducted electron paramagnetic resonance (EPR) and laser flash photolysis studies to determine the possible active intermediates produced. Each antimalarial drug produced at least one EPR adduct with the spin-trap 5,5-dimethyl-1-pyrroline N-oxide in benzene: superoxide/hydroperoxyl adducts (chloroquine, mefloquine, quinacrine, amodiaquine and quinine), carbon-centered radical adducts (all but primaquine), or a nitrogen-centered radical adduct only (primaquine). In ethanol all drugs except primaquine produced some superoxide/hydroperoxyl adduct, with quinine, quinacrine, and hydroxychloroquine also producing the ethoxyl adduct. As detected with flash photolysis and steady-state techniques, mefloquine, quinine, amodiquine and a photoproduct of quinacrine produced singlet oxygen ([symbol: see text]delta = 0.38; [symbol: see text]delta = 0.36; [symbol: see text]delta = 0.011; [symbol: see text]delta = 0.013 in D2O, pD7), but only primaquine quenched singlet oxygen efficiently (2.6 x 10(8) M-1 s-1 in D2O, pD7). Because malaria is a disease most prevalent in regions of high light intensity, protective measures (clothing, sunblock, sunglasses or eye wraps) should be recommended when administering antimalarial drugs.

Advanced uncontrolled glaucoma. Nd:YAG cyclophotocoagulation or tube surgery.

Forty-five patients with advanced uncontrolled glaucoma who had had noncontact neodymium:YAG (Nd:YAG) cyclophotocoagulation were matched and compared with 45 patients who underwent tube implantation surgery. The matching was based on selected criteria, including diagnosis, number of previous operations on the index eye, number of previous glaucoma operations, aphakia, vitrectomy, and age. The drop in intraocular pressure (IOP) was statistically significant in each of the 2 groups at 1, 4, 6, and 12 months of follow-up (P less than 0.001). The tube patients needed fewer antiglaucoma medications at 1 year (P less than 0.025) and more surgical intervention for IOP control, although this was not statistically significant (P greater than 0.1). Laser treatment was repeated in 49% of cases, and age younger than 40 years was identified as a risk factor for poor response to this mode of therapy. The effect on visual acuity and the expected complications also are discussed.

Migrating scleral explants.

Anterior migration of an extrascleral explant is an uncommon complication following buckling procedures. We report five patients where the explant cheesewired through the rectus muscle insertion following retinal detachment surgery. Muscles were not disinserted at the time of surgery in any case. Ocular motility problems were only seen in two patients. The probable mechanisms of this hitherto unreported complication are discussed.

Complete cryptophthalmos: case report with normal flash-VEP and ERG.

We report an infant with bilateral complete cryptophthalmos as part of Fraser Syndrome. Clinical examination and recordings of the electroretinogram and flash visual evoked potential showed a functional visual pathway at retinal and post-retinal levels. Anatomical considerations and the possible complications of surgery made reconstruction of the lids and palpebral fissures inappropriate.

Extended criteria for vitrectomy and fluid/silicone oil exchange.

The results of vitrectomy combined with fluid/silicone oil exchange at six months after surgery in 39 eyes with complex retinal detachments without (initially) severe proliferative vitreoretinopathy, proliferative diabetic retinopathy or giant retinal tears, are reported. Eyes with detachments as a result of macular holes, large multiple or posterior breaks, and eyes which had undergone previous, unsuccessful vitreoretinal surgery are included. In 90% the retina remained reattached, with functional improvement in 72%. These findings, together with the relatively low incidence of complications observed, lead us to recommend this technique in the management of selected detachments falling outside the parameters within which its use is generally accepted.

Hypothalamic hypopituitarism in a patient with a basal encephalocoele--treatment with luteinizing hormone-releasing hormone.

A 20-year-old patient presented with primary amenorrhoea and growth hormone deficiency caused by a basal encephalocoele. She was found to have developed diabetes insipidus in the 8 years following diagnosis. Gonadotrophin release in response to bolus injection of luteinizing hormone-releasing hormone (LHRH) was normal, as was thyrotrophin and adrenocorticotrophin (ACTH) secretion. Pulsatile administration of LHRH by the subcutaneous route resulted in normal ovulation and subsequent menstruation. The investigation and management of patients with basal encephalocoeles are discussed in the light of these findings.

Prospective assessment of regional myocardial perfusion before and after coronary revascularization surgery by quantitative thallium-201 scintigraphy.

Because thallium-201 uptake relates directly to the amount of viable myocardium and nutrient blood flow, the potential for exercise scintigraphy to predict response to coronary revascularization surgery was investigated in 47 consecutive patients. All patients underwent thallium-201 scintigraphy and coronary angiography at a mean (+/- standard deviation) of 4.3 +/- 3.1 weeks before and 7.5 +/- 1.6 weeks after surgery. Thallium uptake and washout were computer-quantified and each of six segments was defined as normal, showing total or partial redistribution or a persistent defect. Persistent defects were further classified according to the percent reduction in regional thallium activity; PD25-50 denoted a 25 to 50% constant reduction in relative thallium activity and PD greater than 50 denoted a greater than 50% reduction. Of 82 segments with total redistribution before surgery, 76 (93%) showed normal thallium uptake and washout postoperatively, versus only 16 (73%) of 22 with partial redistribution (probability [p] = 0.01). Preoperative ventriculography revealed that 95% of the segments with total redistribution had preserved wall motion, versus only 74% of those with partial redistribution (p = 0.01). Of 42 persistent defects thought to represent myocardial scar before surgery, 19 (45%) demonstrated normal perfusion postoperatively. Of the persistent defects that showed improved thallium perfusion postoperatively, 75% had normal or hypokinetic wall motion before surgery, versus only 14% of those without improvement (p less than 0.001). Whereas 57% of the persistent defects that showed a 25 to 50% decrease in myocardial activity demonstrated normal thallium uptake and washout postoperatively, only 21% of the persistent defects with a decrease in myocardial activity greater than 50% demonstrated improved perfusion after surgery (p = 0.02). Thus, preoperative quantitative thallium-201 scintigraphy appears useful in predicting response to revascularization surgery, and some persistent defects may revert to normal thallium uptake after surgery. Importantly, the preoperative distinction between viable and nonviable myocardium can be reasonably established by quantitating the amount of persistent reduction in thallium uptake and correlating this with preoperative wall motion.