Monocyte chemoattractant protein-1 predicts outcome and vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT: Despite efforts to elucidate both the molecular mechanism and the clinical predictors of vasospasm after aneurysmal subarachnoid hemorrhage (ASAH), its pathogenesis remains unclear. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that has been firmly implicated in the pathophysiology of vasospasm and in neural tissue injury following focal ischemia in both animal models and human studies. The authors hypothesized that MCP-1 would be found in increased concentrations in the blood and cerebrospinal fluid (CSF) of patients with ASAH and would correlate with both outcome and the occurrence of vasospasm. METHODS: Seventy-seven patients who presented with ASAH were prospectively enrolled in this study between July 2001 and May 2002. Using an enzyme-linked immunosorbent assay, MCP-1 levels were measured in serum daily and in CSF when available. The mean serum and CSF MCP-1 concentrations were calculated for each patient throughout the entire hospital stay. Neurological outcome was evaluated at discharge or 14 days posthemorrhage using the modified Rankin Scale. Vasospasm was evaluated on angiography. RESULTS: The serum MCP-1 concentrations correlated with negative outcome such that a 10% increase in concentration predicted a 25% increase in the probability of a poor outcome, whereas the serum MCP-1 levels did not correlate with vasospasm. Concentrations of MCP-1 in the CSF, however, proved to be significantly higher in patients with angiographically demonstrated vasospasm. CONCLUSIONS: These findings suggest a role for MCP-1 in neurological injury and imply that it may act as a biomarker of poor outcome in the serum and of vasospasm in the CSF.     

Reliable assessment of laparoscopic performance in the operating room using videotape analysis

The Global Operative Assessment of Laparoscopic Skills (GOALS) is a valid assessment tool for objectively evaluating the technical performance of laparoscopic skills in surgery residents. We hypothesized that GOALS would reliably differentiate between an experienced (expert) and an inexperienced (novice) laparoscopic surgeon (construct validity) based on a blinded videotape review of a laparoscopic cholecystectomy procedure. Ten board-certified surgeons actively engaged in the practice and teaching of laparoscopy reviewed and evaluated the videotaped operative performance of one novice and one expert laparoscopic surgeon using GOALS. Each reviewer recorded a score for both the expert and the novice videotape reviews in each of the 5 domains in GOALS (depth perception, bimanual dexterity, efficiency, tissue handling, and overall competence). The scores for the expert and the novice were compared and statistically analyzed using single-factor analysis of variance (ANOVA). The expert scored significantly higher than the novice did in the domains of depth perception (p = .005), bimanual dexterity (p = .001), efficiency (p = .001), and overall competence ( p = .001). Interrater reliability for the reviewers of the novice tape was Cronbach alpha = .93 and the expert tape was Cronbach alpha = .87. There was no difference between the two for tissue handling. The Global Operative Assessment of Laparoscopic Skills is a valid, objective assessment tool for evaluating technical surgical performance when used to blindly evaluate an intraoperative videotape recording of a laparoscopic procedure.     

Chronic treatment with sildenafil improves energy balance and insulin action in high fat-fed conscious mice

Stimulation of nitric oxide-cGMP signaling results in vascular relaxation and increased muscle glucose uptake. We show that chronically inhibiting cGMP hydrolysis with the phosphodiesterase-5 inhibitor sildenafil improves energy balance and enhances in vivo insulin action in a mouse model of diet-induced insulin resistance. High-fat-fed mice treated with sildenafil plus L-arginine or sildenafil alone for 12 weeks had reduced weight and fat mass due to increased energy expenditure. However, uncoupling protein-1 levels were not increased in sildenafil-treated mice. Chronic treatment with sildenafil plus L-arginine or sildenafil alone increased arterial cGMP levels but did not adversely affect blood pressure or cardiac morphology. Sildenafil treatment, with or without l-arginine, resulted in lower fasting insulin and glucose levels and enhanced rates of glucose infusion, disappearance, and muscle glucose uptake during a hyperinsulinemic (4 mU x kg(-1) x min(-1))-euglycemic clamp in conscious mice. These effects occurred without an increase in activation of muscle insulin signaling. An acute treatment of high fat-fed mice with sildenafil plus l-arginine did not improve insulin action. These results show that phosphodiesterase-5 is a potential target for therapies aimed at preventing diet-induced energy imbalance and insulin resistance.     

Home Improvement: C57BL/6J Mice Given More Naturalistic Nesting Materials Build Better Nests

Environmental enrichment of laboratory mice can improve the quality of research, but debate arises over the means of enrichment and its ability to be used in a sterile environment. One important form of enrichment is nesting material. Mice in the wild build dome-shaped, complex, multilayered nests, but this behavior is not seen in the laboratory, perhaps due to inappropriate nesting material rather than the nest-building ability of the mice. Here we focus on the use of naturalistic nesting materials to test whether they improve nest quality through the use of a ‘naturalistic nest score’ system; we also focus on materials that can be sterilized and easily used in existing housing systems. We first determined whether C57BL/6J mice build naturalistic nests when given shredded paper strips. We then compared these shredded paper strips with other commonly used nesting enrichments (facial tissues and compressed cotton squares). Nests were scored for 6 d. We found that the shredded paper strips allowed the mice to build higher quality nests than those built with any of the other materials. Nests built with tissues were of intermediate quality, and nests built with compressed cotton squares were of poor quality, similar to those built by the control group. These results suggest that C57BL/6J mice given appropriate nesting materials can build nests similar to those built by their wild counterparts.Abbreviation: GLM, generalized linear modelEnvironmental enrichment of laboratory mice has the potential to improve mouse wellbeing, the public perception of mouse research, and the quality of scientific data.^2,16,32 However considerable debate exists over how to provide enrichment for mice, as well as the benefits and costs of practical enrichments.^{4,16,24,27,31} This controversy stems from 2 related issues: most of the enrichments examined in the mouse literature are impractical in a real housing facility; and most commercial ‘enrichments’ have simply been assumed to be beneficial, without testing their effects on the animal. The concept of ‘biological relevance’ provides a way to address these issues as well as a framework for developing practical, effective enrichments.^16,27,32 Here we illustrate this approach, using the development of a nest-building enrichment as an example.The term environmental enrichment, at its broadest, is used for any change in husbandry or caging intended to benefit the animal''s wellbeing.⁵ Changes in husbandry intended to benefit the animal may not always do so for 2 main reasons.³² First, the animal may not respond to the enrichment in the way intended. An animal may simply fail to perceive an enrichment as meaningful, it may find it aversive (as is the case for defensive burying of objects placed in the cage¹⁴), or it may try to defend the enrichment from its cage mates. For example, providing mice with shelves and nest boxes (resources that are thought to be beneficial but can be monopolized) can lead to increased aggression, immunosupression, and prolonged infections.^1,23,27 Second, an enrichment may improve one measure of wellbeing but compromise another. For example, individually ventilated cages (IVC systems) reduce ammonia levels, airborne disease transmission, and the amount of human handling, but mice find the increased ventilations rates aversive,³ show elevated levels of fear or anxiety,²¹ and demonstrate immune suppression.²⁵Several authors have argued that only biologically relevant enrichments—those that allow animals to control stressors in their environment—will actually benefit wellbeing.^16,27,32 For example, when provided with nesting material in ventilated cages, mice no longer find ventilation aversive.³ Furthermore, by giving animals homeostatic control over these stressors, such enrichments should reduce variability and benefit scientific outcomes^16,32 because the environment in which the animal lives considerably affects all aspects of physiology. For example, unenriched or socially isolated animals typically show altered brain development and physiology,²⁸ and the behaviors associated with unenriched environments may indicate altered brain function.¹⁶ Various lines of evidence suggest enrichment renders brains more ‘normal,’ not merely ‘different,’ in comparison to standard-housed animals. For instance, marsh tits (Parus palustris), which are naturally food-storing birds, have a greater hippocampus size than do nonfood storing Parus species. In captivity, however, only marsh tits with food-storing experience show greater hippocampal volume and neuron number, as well as fewer apoptotic cells, compared with those maintained with standard housing.¹¹A subset of biologically relevant enrichments incurs unintended costs. For example, shelters are biologically relevant, but they can induce aggression in group-housed animals.^27,32 These and other conditionally beneficial enrichments may benefit certain types of animals under certain conditions—for example, shelters may provide excellent enrichment for singly housed mice.³² Although some forms of enrichment may be detrimental to some animals, providing nesting material to mice does not appear to incur these kinds of disadvantages ^27,32 (but also see reference ²⁰). Mice show strong preferences for cages that provide nesting material (reviewed in references ¹⁹ and ²⁷), and nest building plays a central role in the natural history of wild mice, suggesting that nesting material may be a highly beneficial enrichment.In the wild, pregnant females tend to build the most complex nests, but nest-building ability extends to males and nonpregnant females.^7,10,22 Mice build nests to provide shelter from the elements, predators, and competitors, but also as a way to compensate for changes in external temperatures.²² Therefore, nests provide external insulation and create a less thermally stressful habitat.¹² The nests typically are built in secluded areas, and their quality at or right after birth is critical for the survival of offspring.¹⁰ If the nests remain undisturbed from outsiders, they generally take on a bowl shape or a dome with an exit hole on 1 side; this shape is most conducive to the survival of offspring.¹⁰ However, nests also can resemble something as simple as a shelf, but this configuration is less advantageous to the success of litters.^6,7,10 Dense colonies of wild house mice can contain a communal nest consisting of several mothers with litters,⁷ and some females with communal nests share them not only with their own litters but also eventually with the litters of their daughters.¹³Therefore, mice in the wild are expert and flexible nest builders, and this behavior is central to their survival, particularly in terms of dealing with challenging environments. However, in the laboratory, the use of nesting enrichments and nest-building behavior can vary, particularly between strains.^8,9,30 In particular, C57BL/6J mice often build rather poor, flat nests when provided with commercial nest-building enrichments.¹⁵ We hypothesized that this variability does not reflect a lack of importance of nest building to C57BL/6J mice but rather that the enrichments provided are not biologically relevant (that is, the mice did not perceive such enrichments as suitable nest-building material). Accordingly, we predicted that if provided with more naturalistic nest-building material, C57BL/6J mice would build nests equivalent to those of their wild counterparts.We first performed a pilot study to determine whether C57BL/6J mice would build naturalistic nests when given shredded paper strips. Having identified a material that allowed mice to build naturalistic nests, we then compared these shredded paper strips with other nesting enrichments to test our hypothesis that poor nest quality reflects the material provided, not the nest-building ability of the mice. Throughout the study, we focused on materials that could be sterilized and easily used in existing housing systems. If these materials are found to be suitable for nest building, then their use is more likely to be implemented across laboratories.     

An Examination of Parent–Child Relationships and Teen Substance Use: A Brief Report

Past studies have indicated strong family bonds may act to buffer against adolescent substance abuse. However, this relationship is not clear, particularly when multiple substances and family dysfunction are examined. In this study, the relationship between alcohol use, marijuana use, and tobacco use and parental relationships were examined in 570 elementary and high school students. Results indicated that support in parent–child relationships was found to be inversely correlated with teen substance use. Clinical implications are discussed in light of these results.     

Glucose transporter type I deficiency syndrome: Epilepsy phenotypes and outcomes

Purpose: Glut 1 deficiency syndrome (DS) is defined by hypoglycorrhachia with normoglycemia, acquired microcephaly, episodic movements, and epilepsy refractory to standard antiepileptic drugs (AEDs). Gold standard treatment is the ketogenic diet (KD), which provides ketones to treat neuroglycopenia. Our purpose is (1) to describe epilepsy phenotypes in a large Glut 1 DS cohort, to facilitate diagnosis; and (2) to describe cases in which non‐KD agents achieved seizure freedom (SF), highlighting potential adjunctive treatments. Methods: Retrospective review of 87 patients with Glut 1 DS (45% female, age range 3 months–35 years, average diagnosis 6.5 years) at Columbia University, from 1989 to 2010. Key Findings: Seventy‐eight (90%) of 87 patients had epilepsy, with average onset at 8 months. Seizures were mixed in 68% (53/78): generalized tonic–clonic (53%), absence (49%), complex partial (37%), myoclonic (27%), drop (26%), tonic (12%), simple partial (3%), and spasms (3%). We describe the first two cases of spasms in Glut 1 DS. Electrophysiologic abnormalities were highly variable over time; only 13 (17%) of 75 had exclusively normal findings. KD was used in 82% (64/78); 67% (41/61) were seizure‐free and 68% of seizure‐free patients (28/41) resolved in <1 week and 76% (31/41) in <1 month. Seven patients achieved SF with broad agents only. Significance: Glut 1 DS is a genetic metabolic encephalopathy with variable focal and multifocal seizure types and electroencephalographic findings. Infants with seizures, spasms, or paroxysmal events should be tested for Glut 1 DS. Evidence is insufficient to recommend specific AEDs as alternatives to KD. Early diagnosis and initiation of KD and prevention of unnecessary AED trials in Glut 1 DS are important goals for the treatment of children with epilepsy.     

Monoallelic silencing and haploinsufficiency in early murine intestinal neoplasms

Studies of tumors from human familial adenomatous polyposis, sporadic colon cancer, and mouse and rat models of intestinal cancer indicate that the majority of early adenomas develop through loss of normal function of the Adenomatous polyposis coli (APC) gene. In murine models of familial adenomatous polyposis, specifically the multiple intestinal neoplasia mouse (Min) and the polyposis in the rat colon (Pirc) rat, most adenomas have lost their WT copy of the Apc gene through loss of heterozygosity by homologous somatic recombination. We report that large colonic adenomas in the Pirc rat have no detectable copy number losses or gains in genomic material and that most tumors lose heterozygosity only on the short arm of chromosome 18. Examination of early mouse and rat tumors indicates that a substantial subset of tumors shows maintenance of heterozygosity of Apc in genomic DNA, apparently violating Knudson's two-hit hypothesis. Sequencing of the Apc gene in a sampling of rat tumors failed to find secondary mutations in the majority of tumors that maintained heterozygosity of Apc in genomic DNA. Using quantitative allele-specific assays of Apc cDNA, we discovered two neoplastic pathways. One class of tumors maintains heterozygosity of Apc(Min/+) or Apc(Pirc/+) RNA expression and may involve haploinsufficiency for Apc function. Another class of tumors exhibits highly biased monoallelic expression of the mutant Apc allele, providing evidence for a stochastic or random process of monoallelic epigenetic silencing of the tumor suppressor gene Apc.