The healing forearm fracture: a matched comparison of forearm refractures

BACKGROUND: Forearm fractures in children usually heal rapidly after closed treatment. Recent studies report forearm refracture rates of 5%. The purpose of this study was to identify risk factors for refracture based on radiographic variables. METHODS: We performed a retrospective review of patients that sustained a second forearm fracture (refracture) between 1998 and 2005. Refractures were defined as having a second fracture of the same forearm within 18 months of the original fracture. A comparison group of single-fracture patients followed in a capitated insurance plan were included and matched based on age and sex. Radiographic assessment included initial/final angulation, displacement, and fracture-line visibility at latest follow-up. RESULTS: Sixty-three refractures were compared with 132 age- and sex-matched single-fracture patients. Time to refracture averaged 10 months. Thirty-eight percent of the initial fractures in the refracture group occurred in the proximal or middle third of the forearm compared with 15% for the single-fracture patients (P < 0.001). Because location of the fracture was found to be a risk factor for refracture, a secondary analysis was performed with refracture patients matched to single-fracture patients based on age, sex, bone fractured, fracture location, and treatment method. Fracture-line visibility of the radius at latest follow-up was clearly visible in 48% of refractures compared with 21% of controls (P = 0.05). Initial fracture severity and residual deformity were not significantly different. CONCLUSIONS: Proximal and middle one third forearm fractures are at greater risk of refracture compared with distal one third forearm fractures. There was a trend toward incomplete healing seen more commonly in those that refractured, emphasizing the importance of longer immobilization in these fractures. LEVEL OF EVIDENCE: Prognostic study, level III, case-control study.     

Water Pipe Tobacco Smoking Among Middle and High School Students

Objectives. We examined prevalence rates of water pipe tobacco smoking among young people as a first step in assessing the health implications of this form of tobacco use.Methods. We examined water pipe use with data from the 2007 Florida Youth Tobacco Survey, which assessed tobacco-related beliefs, attitudes, and behaviors among the state''s middle and high school students.Results. Four percent of middle school students and 11% of high school students reported ever having used a water pipe. Adolescent boys were significantly more likely than adolescent girls to use water pipes, and African American adolescents were significantly less likely than adolescents from other racial/ethnic backgrounds to do so. Those who indicated ever having tried cigarettes and those who reported positive attitudes toward the social nature of cigarette use were more likely to have tried water pipes.Conclusions. Water pipe use appears to be widespread among middle and high school students. Further research is needed to assess the health risks associated with water pipe tobacco smoking as well as young people''s attitudes toward this form of tobacco use.Although the results of self-report studies indicate the apparent popularity of water pipe tobacco (also known as “hookah”) smoking among adolescents and young adults,^1–3 no population-based studies, to our knowledge, have estimated the prevalence of this form of tobacco use. Very little is known regarding water pipe tobacco smoking among adolescent groups. The few self-report studies that have examined use among adolescents have oversampled Arab American students, given the tradition of this form of tobacco use among individuals from the Middle East, Southeast Asia, and South Africa. For example, Weglicki et al.¹ compared water pipe tobacco and cigarette smoking rates among Arab Americans (representing 45% of their sample) and non-Arab Americans. The rate of water pipe use was higher among Arab Americans than among their non–Arab American counterparts (17% vs 11%).¹In addition to assessing patterns of water pipe tobacco smoking, it is important to assess the relationships between water pipe use and use of other tobacco products. Studies have shown that adolescents with a history of water pipe tobacco smoking are 4 to 16.5 times more likely than their counterparts without such a history to experiment with cigarettes.^2,4–6 Also, higher rates of water pipe use have been reported among adolescent males than among adolescent females.^2,5,6Although water pipe smoking is spreading worldwide,⁷ the overall prevalence of this practice in the United States remains unknown. However, estimates are available for certain groups, including college students. Smith et al.,⁸ in describing data collected in 2004, found that 15.3% of freshmen attending an East Coast private university had used a water pipe in the preceding 30 days. In another study, conducted in 2006 at Virginia Commonwealth University, 20.4% of students indicated water pipe use in the preceding 30 days and 48.4% reported a history of water pipe use.⁹In their study of a random sample of students enrolled at a large, urban, public university in the Northeast, Primack et al.¹⁰ found that 9.5% of students had used a water pipe in the preceding 30 days, 31% had done so in the past year, and 41% had a history of water pipe use. Of those who had used a water pipe in the past year, more than one third (35.4%) had never smoked a cigarette.¹⁰ Jackson and Aveyard¹¹ found similar results in a cross-sectional survey of college students who were customers of a water pipe cafe; most students (65%) who reported regular smoking of water pipe tobacco did not smoke cigarettes. Jackson and Aveyard also reported that rates of water pipe use increased across the college years,¹¹ a pattern opposite to that observed with cigarette smoking.¹²In addition to estimating water pipe use rates among different populations in the United States, researchers have assessed perceptions of the risks involved in this practice and the correlates of water pipe tobacco smoking. In a study of students at a private East Coast university, Smith-Simone et al.¹³ found that friends were the most likely source of influence on water pipe use in the following year; also, students reported that water pipe tobacco smoking was the most socially acceptable form of tobacco use among their peers and that their peers looked “cooler” when using water pipes than when smoking cigarettes or cigars.Eissenberg et al.,⁹ in a cross-sectional study conducted at a large public university, found that students who were current water pipe users were more likely than students with no history of water pipe use to have smoked cigarettes, cigars, or cigarillos in the preceding 30 days; to believe that water pipe use makes their peers look cool; and to believe that water pipe use is socially acceptable among their peers. They also found, in general, that water pipe users were younger, that they were less likely to be African American, that they report lower perceived harmfulness or addictiveness of water pipe use compared with cigarette use, and that they report lower perceived social acceptability of cigarette use among peers.In the earlier-mentioned study of Primack et al.,¹⁰ the authors reported that 33% of the college students in their sample believed that water pipe smoking is less harmful than cigarette smoking, and 52% believed that it is less addictive than cigarette smoking. In addition, 36% believed that water pipe smoking is “very socially acceptable.”Although individuals of college age seem to be the group most vulnerable to water pipe use, high school populations are also prone to the increasing popularity of this form of tobacco use, which is primarily social in nature. Many students reach 18 years of age, the legal age to purchase and use tobacco products, while they are still high school seniors, and with the dramatic increase in water pipe cafes (between 2000 and 2004, more than 200 new hookah cafes opened for business nationwide¹⁴), these students now have establishments available to them for water pipe use.To address gaps in the current literature on water pipe tobacco smoking among adolescents, we tested 3 hypotheses. First, older, White, male adolescents will be more likely to use water pipe tobacco than younger, non-White, female adolescents. Second, a history of having tried cigarettes will increase the likelihood of trying water pipe tobacco. Finally, adolescents who believe that cigarettes are acceptable to alleviate stress and for use in social situations will be more likely to use water pipe tobacco.We constructed models designed to assess associations between individual-level variables and water pipe tobacco smoking via hierarchical logistic regression analyses. Demographic data were included in the first model, which tested the hypothesis that water pipe tobacco smoking would be more prevalent among older, White, adolescent boys. We then added history of cigarette use in model 2 to assess our second hypothesis. Finally, in model 3, we assessed whether attitudes toward cigarette smoking with respect to social situations and stress relief would be associated with water pipe tobacco smoking, given that its relaxing and social nature is often cited as a reason for its use.     

Air Pollution and Childhood Respiratory Allergies in the United States

Background

Childhood respiratory allergies, which contribute to missed school days and other activity limitations, have increased in recent years, possibly due to environmental factors.

Objective

In this study we examined whether air pollutants are associated with childhood respiratory allergies in the United States.

Methods

For the approximately 70,000 children from the 1999–2005 National Health Interview Survey eligible for this study, we assigned between 40,000 and 60,000 ambient pollution monitoring data from the U.S. Environmental Protection Agency, depending on the pollutant. We used monitors within 20 miles of the child’s residential block group. We used logistic regression models, fit with methods for complex surveys, to examine the associations between the reporting of respiratory allergy or hay fever and annual average exposure to particulate matter ≤ 2.5 μm in diameter (PM_2.5), PM ≤ 10 μm in diameter, sulfur dioxide, and nitrogen dioxide and summer exposure to ozone, controlling for demographic and geographic factors.

Results

Increased respiratory allergy/hay fever was associated with increased summer O₃ levels [adjusted odds ratio (AOR) per 10 ppb = 1.20; 95% confidence interval (CI), 1.15–1.26] and increased PM_2.5 (AOR per 10 μg/m³ = 1.23; 95% CI, 1.10–1.38). These associations persisted after stratification by urban–rural status, inclusion of multiple pollutants, and definition of exposures by differing exposure radii. No associations between the other pollutants and the reporting respiratory allergy/hay fever were apparent.

Conclusions

These results provide evidence of adverse health for children living in areas with chronic exposure to higher levels of O₃ and PM_2.5 compared with children with lower exposures.     

Nanostructure of liquid crystalline matrix determines in vitro sustained release and in vivo oral absorption kinetics for hydrophilic model drugs

Nanostructured lipid-based liquid crystalline systems have been proposed as sustained oral drug delivery systems, but the interplay between their intrinsic release rates, susceptibility to digestive processes, and the manner in which these effects impact on their application in vivo, are not well understood. In this study, two different bicontinuous cubic phases, prepared from glyceryl monooleate and phytantriol, and a reversed hexagonal phase formed by addition of a small amount of vitamin E to phytantriol (Q(II GMO), Q(II PHYT) and H(II PHYT+VitEA), respectively) were prepared. The release kinetics for a number of model hydrophilic drugs with increasing molecular weights (glucose, Allura Red and FITC-dextrans) was determined in in vitro release experiments. Diffusion-controlled release was observed in all cases as anticipated from previous studies with liquid crystalline systems, and it was discovered that the release rates of each drug decreased as the matrix was changed from Q(II GMO) to Q(II PHYT) to H(II PHYT+VitEA). Formulations containing (14)C-glucose, utilized as a rapidly absorbed marker of drug release, were then orally administered to rats to determine the relative in vivo absorption rates from the different formulations. The results showed a trend by which the rate of absorption of (14)C-glucose followed that observed in the corresponding in vitro release studies, providing the first indication that the nanostructure of these materials may provide the ability to tailor the absorption kinetics of hydrophilic drugs in vivo, and hence form the basis of a new drug delivery system.     

The effects of psychotomimetic and putative cognitive-enhancing drugs on the performance of a n-back working memory task in rats

RATIONALE: Working memory impairment is a core symptom of schizophrenia, but no existing treatment remediates this deficit. Inconsistent conceptualizations and few reliable translational measures are major hindrances to understanding the neurobiology of this aspect of cognition. Using comparable task designs may help bridge clinical and preclinical research efforts. OBJECTIVE: A novel rodent procedure was designed to translate the n-back working memory task used in schizophrenic patients. MATERIALS AND METHODS: Rats were trained in five-lever operant chambers to recall either the last (one-back) or penultimate (two-back) lever from random sequences of lever presentations of variable lengths. Psychotomimetic doses of amphetamine, dizocilpine maleate (MK801), and (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) were tested for disruption of accuracy, and cognitive-enhancing doses of amphetamine, nicotine, and (+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF38393 hydrochloride) were examined for improvements in performance. RESULTS: High doses of amphetamine (0.8 and 1.6 mg/kg) significantly reduced accuracy while increasing total trials; 0.1 mg/kg MK801 and 2.0 mg/kg DOI also reduced accuracy, but the latter concurrently impaired responding. At the lowest dose (0.2 mg/kg), amphetamine increased total trials and rewards without affecting accuracy; 1.0 mg/kg nicotine reduced accuracy without affecting total trials, whereas 10.0 mg/kg SKF38393 had the opposite effect. DISCUSSION: Although the possibility for mediating behaviors may exist, the rodent n-back task provides a clinically relevant model of working memory. Amphetamine and MK801 produced selective impairments without disrupting responding. The cognitive enhancers did not improve working memory, but low doses of amphetamine improved response efficiency. This novel procedure may be useful for examining cognitive deficits and their potential reversal in animal models of schizophrenia.     

Dystrophic neurites in TgCRND8 and Tg2576 mice mimic human pathological brain aging

The morphology and neurochemistry of beta-amyloid (A beta) plaque-associated dystrophic neurites present in TgCRND8 and Tg2576 mice was demonstrated to be strikingly similar to that observed in pathologically aged human cases, but not in Alzheimer's disease (AD) cases. Specifically, pathologically aged cases and both transgenic mouse lines exhibited alpha-internexin- and neurofilament-triplet-labelled ring- and bulb-like dystrophic neurites, but no classical hyperphosphorylated-tau dystrophic neurite pathology. In contrast, AD cases demonstrated abundant classical hyperphosphorylated-tau-labelled dystrophic neurites, but no neurofilament-triplet-labelled ring-like dystrophic neurites. Importantly, quantitation demonstrated that the A beta plaques in TgCRND8 mice were highly axonopathic, and localised displacement or clipping of apical dendrite segments was also associated with A beta plaques in both transgenic mouse models. These results suggest that neuronal pathology in these mice represent an accurate and valuable model for understanding, and developing treatments for, the early brain changes of AD.     

Increased skewing of X chromosome inactivation in Rett syndrome patients and their mothers

Rett syndrome is a largely sporadic, X-linked neurological disorder with a characteristic phenotype, but which exhibits substantial phenotypic variability. This variability has been partly attributed to an effect of X chromosome inactivation (XCI). There have been conflicting reports regarding incidence of skewed X inactivation in Rett syndrome. In rare familial cases of Rett syndrome, favourably skewed X inactivation has been found in phenotypically normal carrier mothers. We have investigated the X inactivation pattern in DNA from blood and buccal cells of sporadic Rett patients (n=96) and their mothers (n=84). The mean degree of skewing in blood was higher in patients (70.7%) than controls (64.9%). Unexpectedly, the mothers of these patients also had a higher mean degree of skewing in blood (70.8%) than controls. In accordance with these findings, the frequency of skewed (XCI > or =80%) X inactivation in blood was also higher in both patients (25%) and mothers (30%) than in controls (11%). To test whether the Rett patients with skewed X inactivation were daughters of skewed mothers, 49 mother-daughter pairs were analysed. Of 14 patients with skewed X inactivation, only three had a mother with skewed X inactivation. Among patients, mildly affected cases were shown to be more skewed than more severely affected cases, and there was a trend towards preferential inactivation of the paternally inherited X chromosome in skewed cases. These findings, particularly the greater degree of X inactivation skewing in Rett syndrome patients, are of potential significance in the analysis of genotype-phenotype correlations in Rett syndrome.