Literature reviews establish the foundation of academic inquires. However, in the planning field, we lack rigorous systematic reviews. In this article, through a systematic search on the methodology ...of literature review, we categorize a typology of literature reviews, discuss steps in conducting a systematic literature review, and provide suggestions on how to enhance rigor in literature reviews in planning education and research.
Background The Asthma Control Test (ACT) has been well validated, but a minimally important difference (MID) has not been established. Objective We sought to identify an MID for the ACT. Methods Data ...come from 4 independent samples of adult asthmatic patients. Distributional methods for determining the MID included 0.5 SD, 1 SEM, and 2 SEM. Anchor-based methods assessed the relationship of differences in ACT scores to (1) self-reported asthma severity, (2) asthma episode frequency in the past 4 weeks, (3) physician ratings of asthma control, (4) physician recommendation of a change in therapy, (5) FEV1 , (6) the risk over the next 12 months of excess short-acting β-agonist use and exacerbations, and (7) patient-defined changes in asthma course over 3 months. Results Four thousand one hundred eighteen patients completed the ACT. The 0.5 SD criterion for MID ranged from 2.03 to 2.45 points (mean, 2.2 points). The 1 SEM criterion ranged from 1.77 to 2.05 points (mean, 1.88 points), and the 2 SEM criterion ranged from 3.55 to 4.10 points (mean, 3.75 points). Differences in mean ACT scores across patient groups differing on criterion measures ranged from 1.06 to 5.28 points (mean, 3.1 points). Predictive analyses showed that a difference of 3 points on the ACT was associated with a subsequent 76% increased risk (95% CI, 73% to 79%) of excess short-acting β-agonist use and a 33% increased risk (95% CI, 31% to 35%) of exacerbations. Conclusion The data support an MID for the ACT of 3 points.
Abstract Objective The objective of this systematic literature review was to evaluate the incidences and risks for adverse events (AEs) associated with oral and parenteral corticosteroids. An ...assessment was performed to estimate the costs of such AEs. Methods A systematic review of literature published from 2007 to 2009 was conducted to identify the incidence rates and risk ratios of corticosteroid-related AEs. The review protocol was developed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The literature search was expanded to include additional search terms for psychiatric conditions, infections, and peptic ulcers. Costs obtained from a separate narrative literature review were applied to AEs likely to affect third-party payers in the United States. Results A total of 357 publications were identified from the primary (n = 323) and secondary (n = 34) searches. Of these, 310 were excluded because they did not evaluate AEs related to corticosteroids, were an excluded publication type, or for other reasons. A final list of 47 studies were used for data extraction. Across patient populations, the most frequently reported corticosteroid-associated AEs were psychiatric events, infections, gastric conditions, and fractures. Corticosteroid-associated AEs reported to occur at an incidence >30% were sleep disturbances, lipodystrophy, adrenal suppression, metabolic syndrome, weight gain, and hypertension. Vertebral fractures were reported at an incidence of 21% to 30%. Dose-response relationships were documented for fractures, acute myocardial infarction, hypertension, and peptic ulcer. The costs of managing AEs that may occur with corticosteroids can be substantial. The literature reported 1-year per-patient costs of up to $26,471.80 for nonfatal myocardial infarction, and per-event costs as high as $18,357.90 for fracture. The findings from the present review should be interpreted cautiously due to several limitations, including the retrospective design of most of the studies identified, risk for confounding due to underlying disease activity or patient population, and the relatively small number of studies that reported each AE association. As this cost analysis was preliminary, a comprehensive pharmacoeconomic analysis should be undertaken to confirm the findings. Conclusion Based on the findings from this review, systemic corticosteroids are a common cause of AEs that may be costly to payers.
Saturated fatty acids, such as palmitate, promote accumulation of ceramide, which impairs activation and signalling of PKB (protein kinase B; also known as Akt) to important end points such as ...glucose transport. SPT (serine palmitoyl transferase) is a key enzyme regulating ceramide synthesis from palmitate and represents a potential molecular target in curbing lipid-induced insulin resistance. In the present study we explore the effects of palmitate upon insulin action in L6 muscle cells in which SPT expression/activity has been decreased by shRNA (small-hairpin RNA) or sustained incubation with myriocin, an SPT inhibitor. Incubation of L6 myotubes with palmitate (for 16 h) increases intramyocellular ceramide and reduces insulin-stimulated PKB activation and glucose uptake. PKB inhibition was not associated with impaired IRS (insulin receptor substrate) signalling and was ameliorated by short-term treatment with myriocin. Silencing SPT expression (approximately 90%) by shRNA or chronic cell incubation with myriocin (for 7 days) markedly suppressed SPT activity and palmitate-driven ceramide synthesis; however, challenging these muscle cells with palmitate still inhibited the hormonal activation of PKB. This inhibition was associated with reduced IRS1/p85-PI3K (phosphoinositide 3-kinase) coupling that arises from diverting palmitate towards greater DAG (diacylglycerol) synthesis, which elevates IRS1 serine phosphorylation via activation of DAG-sensitive PKCs (protein kinase Cs). Treatment of SPT-shRNA cells or those treated chronically with myriocin with PKC inhibitors antagonized palmitate-induced loss in insulin signalling. The findings of the present study indicate that SPT plays a crucial role in desensitizing muscle cells to insulin in response to incubation with palmitate. While short-term inhibition of SPT ameliorates palmitate/ceramide-induced insulin resistance, sustained loss/reduction in SPT expression/activity promotes greater partitioning of palmitate towards DAG synthesis, which impacts negatively upon IRS1-directed insulin signalling.
Local businesses are important for recovering communities, yet program analyses of the effectiveness of Federal disaster loans—particularly for businesses—are limited and contradictory. This study ...looks at the role U.S. Small Business Administration (SBA) Disaster Loans played in the long-term survival of small businesses in Galveston County, Texas after the 2008 Hurricane Ike. This research uses quasi-experimental design, matching methods, and conditional logistic regression to tease out the effect of the loan from potential confounding factors. The results show that businesses that received a disaster loan were significantly more likely to survive than their controls, and businesses that moved were also more likely to survive.
The importance of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) as effectors of metformin (Met) action on glucose uptake (GU) in skeletal muscle cells was investigated. GU in L6 ...myotubes was stimulated 2-fold following 16 h of Met treatment and acutely enhanced by insulin in an additive fashion. Insulin-stimulated GU was sensitive to PI3K inhibition, whereas that induced by Met was not. Met and its related biguanide, phenformin, stimulated AMPK activation/phosphorylation to a level comparable with that induced by the AMPK activator, 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide (AICAR). However, the increase in GU elicited by AICAR was significantly lower than that induced by either biguanide. Expression of a constitutively active AMPK mimicked the effects of AICAR on GU, whereas a dominant interfering AMPK or shRNA silencing of AMPK prevented AICAR-stimulated GU and Met-induced AMPK signaling but only repressed biguanide-stimulated GU by ∼20%. Consistent with this, analysis of GU in muscle cells from α1−/−/α2−/− AMPK-deficient mice revealed a significant retention of Met-stimulated GU, being reduced by ∼35% compared with that of wild type cells. Atypical PKCs (aPKCs) have been implicated in Met-stimulated GU, and in line with this, Met and phenformin induced activation/phosphorylation of aPKC in L6 myotubes. However, although cellular depletion of aPKC (>90%) led to loss in biguanide-induced aPKC phosphorylation, it had no effect on Met-stimulated GU, whereas inhibitors targeting novel/conventional PKCs caused a significant reduction in biguanide-induced GU. Our findings indicate that although Met activates AMPK, a significant component of Met-stimulated GU in muscle cells is mediated via an AMPK-independent mechanism that involves novel/conventional PKCs.
The role of AMPK and PKCs as effectors of metformin action on glucose uptake (GU) in skeletal muscle cells was investigated.
Genetic loss/silencing of AMPK led to only a small repression in metformin-stimulated GU. Novel/conventional, but not atypical, PKCs support metformin-induced stimulation of GU.
Metformin enhances GU by a mechanism largely independent of AMPK.
Metformin can act via non-AMPK pathways to promote GU.
Disaster assistance in the United States has faced criticism for widening the unequal impacts of disasters, but little is known about whether and how this phenomenon applies to businesses. Small ...businesses make up most businesses in the United States, but they are particularly vulnerable to hazards given their relative lack of capital. Because recovery assistance to businesses is primarily loan based, this lack of capital can create conflicts in how aid is perceived and allocated. Assistance providers must balance aiding the most severely damaged businesses and lending to those that will be able to repay; for small business, the threat of additional debt can make even low-interest loans seem risky. With this research I attempted to better understand how these competing factors play out in recovery through regression analyses of approved loan amounts and loan utilization decisions in Galveston (TX) after Hurricane Ike. I found that businesses with higher repayment ability such as larger businesses, older businesses, and corporations were approved for high loan amounts. Smaller businesses, businesses with higher damage, and businesses with longer loan terms were less likely to use the loans in their recovery, despite being approved. These findings suggest that businesses with the resources to recover were more likely to be the ones benefiting from additional disaster assistance.
These findings suggest that planners may need to create their own recovery programs specifically targeting subgroups of businesses that are important to their communities. Although important to many economic development initiatives, very small businesses, entrepreneurs, and sole proprietors may not benefit from federal assistance, particularly if they were severely damaged.
Sustained exposure of pancreatic β cells to an increase in saturated fatty acids induces pleiotropic effects on β-cell function, including a reduction in stimulus-induced insulin secretion. The ...objective of this study was to investigate the effects of chronic over supply of palmitate upon glucose- and amino acid-stimulated insulin secretion (GSIS and AASIS, respectively) and autocrine-dependent insulin signalling with particular focus on the importance of ceramide, ERK and CaMKII signalling.
GSIS and AASIS were both stimulated by >7-fold resulting in autocrine-dependent activation of protein kinase B (PKB, also known as Akt). Insulin release was dependent upon nutrient-induced activation of calcium/calmodulin-dependent protein kinase II (CaMKII) and extracellular signal-regulated kinase (ERK) as their pharmacological inhibition suppressed GSIS/AASIS significantly. Chronic (48 h, 0.4 mM) palmitate treatment blunted glucose/AA-induced activation of CaMKII and ERK and caused a concomitant reduction (~75%) in GSIS/AASIS and autocrine-dependent activation of PKB. This inhibition could not be attributed to enhanced mitochondrial fatty acid uptake/oxidation or ceramide synthesis, which were unaffected by palmitate. In contrast, diacylglycerol synthesis was elevated suggesting increased palmitate esterification rather than oxidation may contribute to impaired stimulus-secretion coupling. Consistent with this, 2-bromopalmitate, a non-oxidisable palmitate analogue, inhibited GSIS as effectively as palmitate.
Our results exclude changes in ceramide content or mitochondrial fatty acid handling as factors initiating palmitate-induced defects in insulin release from MIN6 β cells, but suggest that reduced CaMKII and ERK activation associated with palmitate overload may contribute to impaired stimulus-induced insulin secretion.
Problem, research strategy, and findingsDisaster assistance in the United States has faced criticism for widening the unequal impacts of disasters, but little is known about whether and how this ...phenomenon applies to businesses. Small businesses make up most businesses in the United States, but they are particularly vulnerable to hazards given their relative lack of capital. Because recovery assistance to businesses is primarily loan based, this lack of capital can create conflicts in how aid is perceived and allocated. Assistance providers must balance aiding the most severely damaged businesses and lending to those that will be able to repay; for small business, the threat of additional debt can make even low-interest loans seem risky. With this research I attempted to better understand how these competing factors play out in recovery through regression analyses of approved loan amounts and loan utilization decisions in Galveston (TX) after Hurricane Ike. I found that businesses with higher repayment ability such as larger businesses, older businesses, and corporations were approved for high loan amounts. Smaller businesses, businesses with higher damage, and businesses with longer loan terms were less likely to use the loans in their recovery, despite being approved. These findings suggest that businesses with the resources to recover were more likely to be the ones benefiting from additional disaster assistance.Takeaway for practiceThese findings suggest that planners may need to create their own recovery programs specifically targeting subgroups of businesses that are important to their communities. Although important to many economic development initiatives, very small businesses, entrepreneurs, and sole proprietors may not benefit from federal assistance, particularly if they were severely damaged.
Background The Childhood Asthma Control Test (C-ACT) has demonstrated validity in classifying children aged 4 to 11 years as having either “well-controlled” or “not well-controlled” asthma. However, ...new asthma management guidelines distinguish 3 levels of asthma control. Objective We sought to determine a second cut point on the C-ACT to identify children with “very poorly controlled” asthma. Methods Binomial logistic regression was performed on data from 671 children. The specialist's rating of control was the criterion measure. Specialists' severity ratings, specialists' assessment of therapy, and FEV1 percent predicted were used to assess the clinical validity of the cut point. Results A cut point of 12 was selected because it correctly classified the highest percentage of participants (66.3%) as having “very poorly controlled” (vs “not well controlled”) asthma and demonstrated high specificity (89.8%) and moderate positive predictive value (69.1%). Children scoring 12 or less versus 13 to 19 had lower mean FEV1 percent predicted (79.8% vs 92.6%, P = .0002) and were more frequently stepped up in therapy (72.9% vs 53.6%, P = .0131) and rated as having severe asthma (13.6% vs 4.5%, P = .0005). One month later, significant differences in C-ACT scores and lung function between these 2 groups persisted. The mean C-ACT score of participants classified as “very poorly controlled” was significantly lower than that of participants classified as “not well-controlled” (17.2 vs 20.3, respectively; P = .0001). Conclusion A second cut point of 12 or less on the C-ACT identifies children with the lowest level of control, who are at risk for poorer outcomes, and is conceptually consistent with the classification of “very poorly controlled” asthma adopted by asthma management guidelines.
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