Animal model of simulated microgravity: a comparative study of hindlimb unloading via tail versus pelvic suspension.

The aim of this study was to compare physiological effects of hindlimb suspension (HLS) in tail- and pelvic-HLS rat models to determine if severe stretch in the tail-HLS rats lumbosacral skeleton may contribute to the changes traditionally attributed to simulated microgravity and musculoskeletal disuse in the tail-HLS model. Adult male Sprague-Dawley rats divided into suspended and control-nonsuspended groups were subjected to two separate methods of suspension and maintained with regular food and water for 2 weeks. Body weights, food and water consumption, soleus muscle weight, tibial bone mineral density, random plasma insulin, and hindlimb pain on pressure threshold (PPT) were measured.

A randomized trial of pregabalin in patients with neuropathic pain due to spinal cord injury.

Objective: To assess the efficacy and tolerability of pregabalin for the treatment of central neuropathic pain after spinal cord injury (SCI).

Methods: Patients with chronic, below-level, neuropathic pain due to SCI were randomized to receive 150 to 600 mg/d pregabalin (n = 108) or matching placebo (n = 112) for 17 weeks. Pain was classified in relation to the neurologic level of injury, defined as the most caudal spinal cord segment with normal sensory and motor function, as above, at, or below level.

Attenuation of tissue oxidative stress by dietary restriction in rats on simulated microgravity.

Introduction: Physiologic alterations caused by oxidative stress can be assessed by measuring tissue malondialdehyde (MDA) levels, a biomarker for oxidative stress. The goal of this study is to determine the consequences of a twenty percent caloric restriction on the increased oxidative stress documented in tissues from rats exposed to simulated microgravity.

Materials/methods: Three groups of male SD rats (N=6 in each group) were used: Group 1, control; Group 2, food restricted (20% less food than control); and Group 3, food restricted with HLS.

Pressure hyperalgesia in hind limb suspended rats.

Introduction: Spaceflight and simulated microgravity often associate with pain and prediabetes. Streptozotocin (STZ)-induced moderate insulinopenia rat models of prediabetes result in pressure hyperalgesia. The current study was designed to determine whether or not simulated microgravity induced by hind limb suspension (HLS) in rats lead to insulinopenia and pressure hyperalgesia.

A qualitative evaluation of patients' experiences of an enhanced recovery programme for colorectal cancer.

Aim: We explored the patients' views and experiences of surgery for colorectal cancer within an enhanced recovery programme (ERP).

Method: Semi-structured home interviews were performed within 6 weeks of hospital discharge with participants of a randomized trial comparing laparoscopically assisted surgery with open surgery for colorectal cancer within an ERP. Interviews were tape-recorded, transcribed and analysed using qualitative techniques of constant comparison based upon grounded theory.

Physiological signaling specificity by protein tyrosine phosphatases.

Protein tyrosine phosphatases (PTPs) are now recognized to be involved in a multitude of signaling events that control fundamental biological processes such as cell growth, differentiation, apoptosis, and cell movement. PTPs, which were initially thought to be less discriminating in their actions compared with their protein tyrosine kinase counterparts, are now known to regulate these various biological processes in a precise manner. This review will focus on the concept that PTPs exhibit remarkable signaling specificity through intrinsic differences between their PTP domains and through various modes of regulation that endows them with the capacity to promote unique physiological responses.

Effects of aminoguanidine on tissue oxidative stress induced by hindlimb unloading in rats.

We investigated the effects of hindlimb unloading (HLU) on malondialdehyde (MDA), a biomarker for oxidative stress, and glutathione (GSH) levels in tissues of rats. Aminoguanidine (AG), a nucleophilic hydralazine compound and an in vivo antioxidant against reactive oxygen species (ROS) and lipid peroxidation, was used to confirm the HLU-induced oxidative response. Three groups of rats were used: Group 1 was a loaded control group that was maintained on drinking water only; Groups 2 and 3 were hindlimb unloaded (HLU) groups that were maintained on drinking water and on AG in drinking water, respectively.

L-carnitine influence on oxidative stress induced by hind limb unloading in adult rats.

Introduction: An improvement in the imbalance in the oxidant-antioxidant defense system would lessen the severity of any oxidative stress documented during or after spaceflight. In this study, we investigated the effects of a 14-d hind limb unloading (HLU) of rats on the formation of malondialdehyde (MDA), an oxidative biomarker and also an end-product of lipid peroxidation, in tissues and blood of rats. L-carnitine, a well-known enhancer of activities of the mitochondrial antioxidant system, was used to confirm the HLU-induced oxidative response.

Calcium mobilization via type III inositol 1,4,5-trisphosphate receptors is not altered by PKA-mediated phosphorylation of serines 916, 934, and 1832.

Several studies have shown that PKA-mediated phosphorylation of IP3R1 at serines S1588 and S1755 enhances the receptor's ability to mobilize Ca2+. In contrast, much less is known about whether Ca2+ mobilization via IP3R2 and IP3R3 is regulated by PKA. We report here that IP3R2 is only very weakly phosphorylated in response to PKA activation and is probably not a physiological substrate for this kinase.

The influence of an enhanced recovery programme on clinical outcomes, costs and quality of life after surgery for colorectal cancer.

Objective: Optimizing peri-operative care using an enhanced recovery programme improves short-term outcomes following colonic resection. This study compared a prospective group of patients undergoing resection of colorectal cancer within an enhanced recovery programme, with a prospectively studied historic cohort receiving conventional care.

Patients And Methods: Sixty patients underwent elective resection within an enhanced recovery programme (ERP).

The type III inositol 1,4,5-trisphosphate receptor is phosphorylated by cAMP-dependent protein kinase at three sites.

IP3 (inositol 1,4,5-trisphosphate) receptors form tetrameric, IP3-gated Ca2+ channels in endoplasmic reticulum membranes, and are substrates for several kinases, including PKA (cAMP-dependent protein kinase). Activation of PKA has been reported to either enhance or inhibit type III IP3 receptor Ca2+-channel activity, but, as yet, the sites of phosphorylation remain unknown. Here, we reveal that PKA phosphorylates the type III IP3 receptor at Ser916, Ser934 and Ser1832, and that, intriguingly, each site is located close to a putative surface-exposed peptide loop.

Brief communication: Effects of soy-protein diet on elevated brain lipid peroxide levels induced by simulated weightlessness.

The influence of soy-protein diet on brain lipid peroxidation in female rats was studied using a tail-suspension model of weightlessness. The study tested the efficacy of diets containing 0% or 11.1% soy-protein in 4 groups of female Sprague Dawley rats that were maintained with or without tail-suspension for a period of 3 weeks.

The contribution of serine residues 1588 and 1755 to phosphorylation of the type I inositol 1,4,5-trisphosphate receptor by PKA and PKG.

Type I inositol 1,4,5-trisphosphate receptors can be phosphorylated by cAMP-dependent protein kinase (PKA) and cGMP-dependent protein kinase (PKG). To define the site-specificity of these events we analyzed the phosphorylation of mutant receptors expressed in intact cells. These studies showed that S(1588) and S(1755), the serine residues within kinase consensus sequences, are equally sensitive to PKA, that phosphorylation events at these sites are independent of each other, and that PKG predominantly phosphorylates S(1588).

2-Aminoethoxydiphenyl borate inhibits inositol 1,4,5-trisphosphate receptor function, ubiquitination and downregulation, but acts with variable characteristics in different cell types.

2-Aminoethoxydiphenyl borate (2-APB) is a putative, membrane-permeable inhibitor of inositol 1,4,5-trisphosphate (InsP(3)) receptors, but it is the case that little is known about its action at the InsP(3) receptor level. Thus, we examined the effects of 2-APB on InsP(3) receptor-mediated effects in a range of cell types expressing different complements of InsP(3) receptor types. In experiments with permeabilized cells we found that 2-APB could inhibit InsP(3)-induced release of stored Ca(2+), but also that it released Ca(2+), and that the prevalence of these two effects varied between different cell types and did not correlate with the expression of a particular receptor type.

Lipid peroxidation in rat brain is increased by simulated weightlessness and decreased by a soy-protein diet.

This study tested whether or not simulated weightlessness by tail-suspension increases the levels of lipid peroxidation products in rat brain. The brain tissues of rats on a soybean diet were also assayed for lipid peroxidation products to evaluate the possible role of soy-protein as a dietary anti-oxidant. Male Sprague-Dawley rats were used.

Evaluation of the PuriLens contact lens care system: an automatic care system incorporating UV disinfection and hydrodynamic shear cleaning.

Purpose: This study evaluates lens care using the PuriLens System, an advanced way to clean and disinfect soft hydrophilic lenses using subsonic agitation and UV radiation, respectively.

Methods: A two-period crossover lens cleaning and safety investigation was conducted using 80 patients. Disinfecting efficacy was tested in accordance with standard FDA protocols.

Distribution of 3H-nicotine in rat tissues under the influence of simulated microgravity.

Rat tail suspension offers a useful model to reproduce physiologic responses to weightlessness. The present study was conducted in the head-down-tilt (HDT) rat model to assess changes in metabolism of body tissues employing 3H-nicotine. Twelve male rats were used in the study.

Mini radial keratotomy reduces ocular integrity. Axial compression in a postmortem porcine eye model.

Objective: This study aimed to examine ocular rupture force in pig eyes after "minimally invasive radial keratotomy" (MRK) and standard radial keratotomy (SRK).

Design: Experimental study.

Materials: A total of 71 pairs of pig eyes (51 control eyes) were examined.

Effects of lidocaine on atrial natriuretic peptide concentrations in plasma and urine.

The antiarrhythmic agent lidocaine reduces inward sodium current and increases outward potassium current. Described studies investigated the effect of lidocaine on circulating and urinary levels of atrial natriuretic peptides in an intact canine model. Surface electrocardiography was monitored along with right ventricular, left ventricular and aortic pressures, and cardiac output.

Tensile strength of insertional suture techniques in strabismus surgery.

Background: The "lost" extraocular muscle is a serious adverse outcome of seemingly uncomplicated strabismus surgery. One potential cause of this complication is suture slippage in the operated muscle or tendon. The purpose of this study was to determine the relative tensile strengths of three suture techniques commonly used in strabismus surgery and to compare the incidence of suture slippage in the tendon or muscle among these techniques.

Effect of antagonist weakening on developed tension in cat extraocular muscle.

Purpose: In a previous study, the authors found that recession of an extraocular muscle resulted in atrophy of both the recessed muscle and its antagonist. To determine if atrophy, caused by weakening of an extraocular muscle, results in changes in developed tension in the antagonist, the authors studied force development of the cat lateral rectus muscle after adductor weakening.

Methods: Tenotomy of the left inferior, medial, and superior rectus muscles was performed in 18 cats.

Vessel dilator is associated with survival after acute myocardial infarction.

To assess whether infarct size, ischemic area and/or survival correlates with circulating atrial natriuretic peptides (long acting sodium stimulator, vessel dilator, or atrial natriuretic factor), these peptides were measured in a canine model of acute myocardial infarction. Elevations in the circulating concentrations of atrial natriuretic factor, vessel dilator, and long acting sodium stimulator were significant (P < 0.05) within 6 min of coronary occlusion of the left anterior descending coronary artery.