Does smoking cessation increase risk of knee replacement? a general population-based cohort study.

OBJECTIVE: Smoking represents a major issue for global public health. Owing to methodologic challenges, findings of an association between smoking and risk of knee osteoarthritis (OA) are inconsistent. We sought to assess the relation of onset of smoking cessation to the risk of OA sequelae, i.e., knee replacement, and to perform sub-cohort analysis according to weight change after smoking cessation. DESIGN: Using The Health Improvement Network, we conducted a cohort study to examine the association between smoking cessation and risk of knee replacement among patients with knee OA. Participants who stopped smoking were further grouped into three sub-cohorts: weight gain (body mass index [BMI] increased>1.14 kg/m2), no substantial weight change (absolute value of BMI change<1.14 kg/m2), and weight loss (BMI loss>1.14 kg/m2) after smoking cessation. RESULTS: We identified 108 cases of knee replacement among 1,054 recent quitters (26.7/1,000 person-years) and 1,108 cases among 15,765 current smokers (17.4/1,000 person-years). The rate difference of knee replacement in recent quitter cohort vs current smoker cohort was 10.4 (95% confidence interval [CI]:5.3-15.6)/1,000 person-years and the adjusted hazard ratio (HR) was 1.30 (95%CI:1.05-1.59). Compared with current smokers, risk of knee replacement was higher among quitters with weight gain (HR = 1.42,95%CI:1.01-1.98), but not among those with no substantial weight change (HR = 1.29,95%CI:0.90-1.83) or those with weight loss (HR = 1.11,95%CI:0.71-1.75). CONCLUSIONS: Our large population-based cohort study provides the first evidence that smoking cessation was associated with a higher risk of knee replacement among individuals with knee OA, and such an association was due to weight gain after smoking cessation.

Novel use of repolarization parameters in electrocardiographic imaging to uncover arrhythmogenic substrate.

BACKGROUND: Measuring repolarization characteristics is challenging and has been reserved for experienced physicians. In electrocardiographic imaging (ECGI), activation-recovery interval (ARI) is used as a measure of local cardiac repolarization duration. We hypothesized that repolarization characteristics, such as local electrogram morphology and local and global dispersion of repolarization timing and duration could be of significance in ECGI. OBJECTIVE: To further explore their potential in arrhythmic risk stratification we investigated the use of novel repolarization parameters in ECGI. MATERIALS AND METHODS: We developed and compared methods for T-peak and T-end detection in reconstructed potentials. All methods were validated on annotated reconstructed electrograms (EGMs). Characteristics of the reconstructed EGMs and epicardial substrate maps in IVF patients were analyzed by using data recorded during sinus rhythm. The ECGI data were analyzed for EGM morphology, conduction, and repolarization. RESULTS: We acquired ECGI data from 8 subjects for this study. In all patients we evaluated four repolarization parameters: Repolarization time, T-wave area, Tpeak-Tend interval, and T-wave alternans. Most prominent findings were steep repolarization time gradients in regions with flat EGMs. These regions were also characterized by low T-wave area and large differences in Tpeak-Tend interval. CONCLUSIONS: Measuring novel repolarization parameters in reconstructed electrograms acquired with ECGI is feasible, can be done in a fully automated manner and may provide additional information on underlying arrhythmogenic substrate for risk stratification. Further studies are needed to investigate their potential use and clinical application.

Contribution of bone turnover markers to the variation in bone mineral density: a study in Vietnamese men and women.

The present cross-sectional study constructed reference ranges for bone resorption marker beta isomerized form of C-terminal crosslinking telopeptides of type I collagen (beta-CTX) and bone formation marker procollagen type 1 N-terminal propeptide (PINP) for the Vietnamese population. We have further shown that for a given age and weight, higher levels of beta-CTX were significantly associated with bone mineral density in men and women. INTRODUCTION: Normal bone is constantly renewed by two opposing processes of resorption and formation which can be reflected by bone turnover markers (BTMs). This study sought to define the contribution of BTMs to the variation in bone mineral density (BMD) in normal individuals. METHODS: The study involved 205 men and 432 women aged between 18 and 87, who were randomly selected from various districts within Ho Chi Minh City, Vietnam. Fasting serum levels of PINP and beta-CTX were determined by electrochemiluminescence (Roche, ECLIA). BMD at the lumbar spine (LS) and femoral neck (FN) was measured by dual-energy x-ray absorptiometry (Hologic, Waltham, MA, USA). RESULTS: Among those aged < 50 years, women had lower PINP and beta-CTX levels than men, but among those aged > 50 years, women had higher PINP and beta-CTX levels than men. In the multiple linear regression analysis, beta-CTX-but not PINP-was significantly associated with both femoral neck (P = 0.008) and lumbar spine BMD (P = 0.008) and the association was independent of gender, age, and body weight. The proportion of variance in BMD attributable to beta-CTX was 1% for femoral neck BMD and 2% for lumbar spine BMD. CONCLUSION: The elevation in bone formation marker PINP and bone resorption marker beta-CTX in postmenopausal women was greater than in elderly men. However, only beta-CTX was modestly but significantly associated with BMD.

Inhibition of RhoA reduces propofol-mediated growth cone collapse, axonal transport impairment, loss of synaptic connectivity, and behavioural deficits.

BACKGROUND: Exposure of the developing brain to propofol results in cognitive deficits. Recent data suggest that inhibition of neuronal apoptosis does not prevent cognitive defects, suggesting mechanisms other than neuronal apoptosis play a role in anaesthetic neurotoxicity. Proper neuronal growth during development is dependent upon growth cone morphology and axonal transport. Propofol modulates actin dynamics in developing neurones, causes RhoA-dependent depolymerisation of actin, and reduces dendritic spines and synapses. We hypothesised that RhoA inhibition prevents synaptic loss and subsequent cognitive deficits. The present study tested whether RhoA inhibition with the botulinum toxin C3 (TAT-C3) prevents propofol-induced synapse and neurite loss, and preserves cognitive function. METHODS: RhoA activation, growth cone morphology, and axonal transport were measured in neonatal rat neurones (5-7 days in vitro) exposed to propofol. Synapse counts (electron microscopy), dendritic arborisation (Golgi-Cox), and network connectivity were measured in mice (age 28 days) previously exposed to propofol at postnatal day 5-7. Memory was assessed in adult mice (age 3 months) previously exposed to propofol at postnatal day 5-7. RESULTS: Propofol increased RhoA activation, collapsed growth cones, and impaired retrograde axonal transport of quantum dot-labelled brain-derived neurotrophic factor, all of which were prevented with TAT-C3. Adult mice previously treated with propofol had decreased numbers of total hippocampal synapses and presynaptic vesicles, reduced hippocampal dendritic arborisation, and infrapyramidal mossy fibres. These mice also exhibited decreased hippocampal-dependent contextual fear memory recall. All anatomical and behavioural changes were prevented with TAT-C3 pre-treatment. CONCLUSION: Inhibition of RhoA prevents propofol-mediated hippocampal neurotoxicity and associated cognitive deficits.

Visualisation of coronary venous anatomy by computed tomography angiography prior to cardiac resynchronisation therapy implantation.

BACKGROUND: The purpose of this study was to illustrate the additive value of computed tomography angiography (CTA) for visualisation of the coronary venous anatomy prior to cardiac resynchronisation therapy (CRT) implantation. METHODS: Eighteen patients planned for CRT implantation were prospectively included. A specific CTA protocol designed for visualisation of the coronary veins was carried out on a third-generation dual-source CT platform. Coronary veins were semi-automatically segmented to construct a 3D model. CTA-derived coronary venous anatomy was compared with intra-procedural fluoroscopic angiography (FA) in right and left anterior oblique views. RESULTS: Coronary venous CTA was successfully performed in all 18 patients. CRT implantation and FA were performed in 15 patients. A total of 62 veins were visualised; the number of veins per patient was 3.8 (range: 2-5). Eighty-five per cent (53/62) of the veins were visualised on both CTA and FA, while 10% (6/62) were visualised on CTA only, and 5% (3/62) on FA only. Twenty-two veins were present on the lateral or inferolateral wall; of these, 95% (21/22) were visualised by CTA. A left-sided implantation was performed in 13 patients, while a right-sided implantation was performed in the remaining 2 patients because of a persistent left-sided superior vena cava with no left innominate vein on CTA. CONCLUSION: Imaging of the coronary veins by CTA using a designated protocol is technically feasible and facilitates the CRT implantation approach, potentially improving the outcome.

Using a standardised protocol was effective in reducing hospitalisation and treatment use in children with newly diagnosed immune thrombocytopenia.

AIM: Childhood immune thrombocytopenia (ITP) has been associated with low bleeding rates and a high frequency of spontaneous remission. Although current guidelines suggest that most patients are just observed, children still receive platelet-enhancing therapies for fear of bleeding complications. We hypothesised that a standardised protocol with a step-down approach would reduce hospitalisation and treatment use. METHOD: A retrospective chart review was performed on patients diagnosed with acute ITP between January 2010 and December 2014, before (n = 54) and after (n = 37) the standardised protocol, which was introduced in January 2013. Management and events during the first 3 months following diagnosis were recorded. RESULTS: The protocol resulted in a 34% decrease in the hospitalisation rate (p < 0.001) at diagnosis. Prednisone treatment duration at diagnosis was also significantly reduced (13.1 versus 5.8 days, p = 0.004). Children over 3 years of age were 3.8 times less likely to be hospitalised (95% CI 1.94-7.61) and 2.3 times less likely to receive treatment (95% CI 1.2-4.3). There was no difference in the rate of persistent ITP (38% versus 30%, p = 0.43) or serious bleeding complications (7% versus 5%, p = 0.70). CONCLUSION: Our ITP management protocol significantly reduced hospitalisation rates and length of prednisone treatment without any increase in disease complications.

The association between antagonist hamstring coactivation and episodes of knee joint shifting and buckling.

OBJECTIVE: Hamstring coactivation during quadriceps activation is necessary to counteract the quadriceps pull on the tibia, but coactivation can be elevated with symptomatic knee osteoarthritis (OA). To guide rehabilitation to attenuate risk for mobility limitations and falls, this study evaluated whether higher antagonistic open kinetic chain hamstring coactivation is associated with knee joint buckling (sudden loss of support) and shifting (a sensation that the knee might give way). DESIGN: At baseline, median hamstring coactivation was assessed during maximal isokinetic knee extensor strength testing and at baseline and 24-month follow-up, knee buckling and shifting was self-reported. Associations between tertiles of co-activation and knee (1) buckling, (2) shifting and (3) either buckling or shifting were assessed using logistic regression, adjusted for age, sex, knee OA and pain. RESULTS: 1826 participants (1089 women) were included. Mean ± SD age was 61.7 ± 7.7 years, BMI was 30.3 ± 5.5 kg/m(2) and 38.2% of knees had OA. There were no consistent statistically significant associations between hamstring coactivation and ipsilateral prevalent or incident buckling or the combination of buckling and shifting. The odds ratios for incident shifting in the highest in comparison with the lowest tertile of coactivation had similar magnitudes in the combined and medial hamstrings, but only reached statistical significance for lateral hamstring coactivation, OR(95%CI) 1.53 (0.99, 2.36). CONCLUSIONS: Hamstring coactivation during an open kinetic chain quadriceps exercise was not consistently associated with prevalent or incident self-reported knee buckling or shifting in older adults with or at risk for knee OA.

The impact of knee instability with and without buckling on balance confidence, fear of falling and physical function: the Multicenter Osteoarthritis Study.

OBJECTIVE: Knee buckling, in which a knee gives way during weight-bearing, is common in people with knee pain and knee osteoarthritis (OA), but little is known about the prevalence of sensations of knee instability, slipping or shifting in which the knee does not actually buckle, or of the psychosocial and physical consequences of these symptoms. DESIGN: We asked participants in the Multicenter Osteoarthritis Study (MOST) separately about episodes of knee buckling and sensations of knee instability without buckling in the past 3 months, and assessed fear of falling, poor balance confidence (Activities-specific Balance Confidence (ABC) Scale ≤ 67/100), activity limitation due to concern about buckling, and poor physical function (Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical function ≥ 28/68). We used Poisson regression to estimate prevalence ratios (PRs) for cross-sectional associations of buckling and sensations of instability without buckling with these outcomes, adjusting for confounders. RESULTS: Of 2120 participants (60% female, 40% ≥ 65 years, mean Body mass index (BMI): 31 kg/m258), 18% reported buckling, 27% had sensations of knee instability without buckling, and 9% reported both symptoms. Buckling and sensations of instability without buckling were each significantly associated with fear of falling, poor balance confidence, activity limitations, and poor WOMAC physical function. Subjects who reported both buckling and instability without buckling and those with at least two buckling episodes (15%) had the strongest association with poor outcomes. CONCLUSIONS: Knee buckling and especially sensations of knee instability without buckling were common and each was significantly associated with fear of falling, poor balance confidence, activity limitations, and poor physical function.

Biomarkers for monitoring heavy metal pollution in the Anzali Wetland.

This research aims to investigate biochemical activities of Phragmites australis, as a biomarker of heavy metals including Cr, Ni, V, Zn and Co. In order to determine and analyze biochemical parameters including flavonoids, Non-Protein Thiols (NPTs), chlorophyll a and b and total chlorophyll pigments in the roots, stems and leaves of P. australis, sediment and plant samples were collected from 7 stations in the Anzali wetland. Based on the obtained results, there were positive and significant correlation coefficients among the concentrations of the heavy metals in the sediments with non-protein thiols and flavonoids, also negative and significant correlation coefficients were found between the heavy metal contents and the total chlorophyll in the leaves in all the sampling stations. Therefore, it can be concluded that these parameters are appropriate biomarkers to evaluate the heavy metal pollution in the sediments of the aquatic ecosystem.

Exposure to bisphenol A differentially impacts neurodevelopment and behavior in Drosophila melanogaster from distinct genetic backgrounds.

Bisphenol A (BPA) is a ubiquitous environmental chemical that has been linked to behavioral differences in children and shown to impact critical neurodevelopmental processes in animal models. Though data is emerging, we still have an incomplete picture of how BPA disrupts neurodevelopment; in particular, how its impacts may vary across different genetic backgrounds. Given the genetic tractability of Drosophila melanogaster, they present a valuable model to address this question. Fruit flies are increasingly being used for assessment of neurotoxicants because of their relatively simple brain structure and variety of measurable behaviors. Here we investigated the neurodevelopmental impacts of BPA across two genetic strains of Drosophila-w1118 (control) and the Fragile X Syndrome (FXS) model-by examining both behavioral and neuronal phenotypes. We show that BPA induces hyperactivity in larvae, increases repetitive grooming behavior in adults, reduces courtship behavior, impairs axon guidance in the mushroom body, and disrupts neural stem cell development in the w1118 genetic strain. Remarkably, for every behavioral and neuronal phenotype examined, the impact of BPA in FXS flies was either insignificant or contrasted with the phenotypes observed in the w1118 strain. This data indicates that the neurodevelopmental impacts of BPA can vary widely depending on genetic background and suggests BPA may elicit a gene-environment interaction with Drosophila fragile X mental retardation 1 (dFmr1)-the ortholog of human FMR1, which causes Fragile X Syndrome and is associated with autism spectrum disorder.

Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston Study.

OBJECTIVE: To examine potential risk factors for hallux valgus in community-dwelling elders. METHOD: Data from 600 MOBILIZE Boston Study participants (386 women and 214 men) were analyzed. Hallux valgus was defined as >15 degrees angular deviation of the hallux with respect to the first metatarsal bone toward the lesser toes. Associations of hallux valgus with age, body mass index (BMI), race, education, pes planus, foot pain, and in women, history of high heel shoe use, were assessed using sex-specific Poisson regression with robust variance estimation for risk ratios (RR) and 95% confidence intervals (CI). RESULTS: Hallux valgus was present in 58% of women and 25% of men. Higher BMI was inversely associated with presence of hallux valgus in women (P trend=0.001), with the strongest inverse association observed in those with BMI of 30.0 or more compared to those with normal BMI (RR=0.7, 95% CI: 0.5, 0.9). Women, who usually wore high-heeled shoes during ages 20-64 years compared to those who did not, had increased likelihood of hallux valgus (RR=1.2, 95% CI: 1.0, 1.5). Among men, those with BMI between 25.0 and 29.9 had increased likelihood of hallux valgus compared to those with normal BMI (RR=1.9, 95% CI: 1.0, 3.5). Men with pes planus were more likely to have hallux valgus (RR=2.1, 95% CI: 1.3, 3.3) compared to men without pes planus. CONCLUSION: In women, hallux valgus was associated with lower BMI and high heel use during ages 20-64, while in men, associations were observed with higher BMI and pes planus. Our results suggest that the etiologic mechanisms for hallux valgus may differ between men and women.

A rule-based method for predicting the electrical activation of the heart with cardiac resynchronization therapy from non-invasive clinical data.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) is one of the few effective treatments for heart failure patients with ventricular dyssynchrony. The pacing location of the left ventricle is indicated as a determinant of CRT outcome. OBJECTIVE: Patient specific computational models allow the activation pattern following CRT implant to be predicted and this may be used to optimize CRT lead placement. METHODS: In this study, the effects of heterogeneous cardiac substrate (scar, fast endocardial conduction, slow septal conduction, functional block) on accurately predicting the electrical activation of the LV epicardium were tested to determine the minimal detail required to create a rule based model of cardiac electrophysiology. Non-invasive clinical data (CT or CMR images and 12 lead ECG) from eighteen patients from two centers were used to investigate the models. RESULTS: Validation with invasive electro-anatomical mapping data identified that computer models with fast endocardial conduction were able to predict the electrical activation with a mean distance errors of 9.2 ±â€¯0.5 mm (CMR data) or (CT data) 7.5 ±â€¯0.7 mm. CONCLUSION: This study identified a simple rule-based fast endocardial conduction model, built using non-invasive clinical data that can be used to rapidly and robustly predict the electrical activation of the heart. Pre-procedural prediction of the latest electrically activating region to identify the optimal LV pacing site could potentially be a useful clinical planning tool for CRT procedures.

An immunofluorescence study of the calcium-induced coordinated reorganization of microfilaments, keratin intermediate filaments, and microtubules in cultured human epidermal keratinocytes.

Indirect immunofluorescence microscopy has been used to investigate the coordinated reorganization of microtubules, microfilaments, and keratin intermediate filaments in cultured human epidermal keratinocytes following a switch from low-Ca++ (0.15 mM) medium to high-Ca++ (1.05 mM) medium. A dramatic reorganization occurs concurrently in the three major cytoskeletal components shortly after the calcium switch. The most prominent features are the alignment of keratin filaments at the plasma membranes of apposed cells, the induction of microfilament rings, the restriction of microtubules to the area within the boundaries of the microfilament rings, and the alignment of actin bundles at cell borders. Additional changes are observed in terminally differentiated cells. This is the first report that describes simultaneous changes in the organization of the three major cytoskeletal components of epidermal keratinocytes. Cytochalasin D and demecolcine (colcemid) studies were performed to determine whether the organization of microtubules, microfilaments, and keratin filaments, as well as the calcium-induced reorganization of these cytoskeletal elements, may be dependent on the existence of structural relationships between them. These studies demonstrate that the disruption of microfilaments results in the formation of a latticelike keratin network, with a close association of actin and keratin being maintained. The formation of keratin filament alignments occurs even in the absence of intact microfilaments. In addition, it was found that the Ca(++)-induced reorganization of microfilaments and keratin filaments is not dependent on an intact microtubule network. Furthermore, the reorganization of actin into concentric rings can be dissociated from changes in the organization of keratin filaments.

Aspartame ingestion increases urinary calcium, but not oxalate excretion, in healthy subjects.

Aspartame is the artificial sweetener most extensively used as a substitute for glucose or sucrose in the food industry, particularly in soft drinks. As glucose ingestion increases calciuria and oxaluria, the two main determinants of urinary calcium-oxalate saturation, we considered it worthwhile to determine whether aspartame ingestion also affects calcium-oxalate metabolism. Our study compares the effects of the ingestion of similarly sweet doses of aspartame (250 mg) and glucose (75 g) on calcium and oxalate metabolisms of seven healthy subjects. Urinary calcium excretion increased after the intake of both aspartame (+86%; P < 0.01) and glucose (+124%; P < 0.01). This may be due to the rise in calcemia observed after both aspartame (+2.2%; P < 0.05) and glucose ingestion (+1.8%; P < 0.05). The increased calcemia may be linked to the decrease in phosphatemia that occurred after both aspartame (P < 0.01) and glucose (P < 0.01) load. Aspartame did not alter glycemia or insulinemia, whereas glucose intake caused striking increases in both glycemia (+59%; P < 0.001) and insulinemia (+869%; P < 0.01). Although insulin was considered the main calciuria-induced factor after glucose load, it is unlikely that this mechanism played a role with aspartame. Urinary oxalate excretion did not change after aspartame, whereas it increased (+27%; P < 0.05) after glucose load. Thus, as aspartame induced a similar increase in calciuria as did glucose but, conversely, no change in oxaluria, substituting glucose by aspartame in soft drinks may appear to be of some potential benefit.

Ovariectomy has minimal effects on neuroadaptations associated with ethanol dependence in female rats.

We previously found gender selective alterations in gene expression for GABA(A) and NMDA receptors associated with the development of ethanol dependence. Males and females have a differing hormonal environment, including steroid hormone derivatives (neuroactive steroids) that exert effects at GABA(A) and NMDA receptors. Therefore, we explored whether the removal of ovarian steroids would alter gender differences in response to chronic ethanol exposure. We found that ovariectomy reduced ethanol drinking levels by 15%, comparable to earlier observations between intact female and male rats. However, investigation of the effects of chronic ethanol exposure on intact versus ovariectomized female rats uncovered few differences in chronic ethanol-induced alterations in selected GABA(A) or NMDA receptor subunit peptide levels. In general, findings for both groups of females were similar to previous observations. There was no reduction in GABA(A) receptor alpha1 subunit levels in cerebral cortex in either intact or ovariectomized female rats, in contrast to the significant reduction observed in male rats. In addition, both intact and ovariectomized female rats had increased levels of the NMDA NR1 subunit in cerebral cortex and hypothalamus, but not in hippocampus, whereas ethanol dependent male rats displayed significant increases in the NR1 subunit only in hippocampus. Radioligand binding analysis with [35S]TBPS found no differences in modulation of the GABA(A) receptor by neuroactive steroids between ethanol dependent male, intact female or ovariectomized female rats. Seizure susceptibility was not different between intact or ovariectomized female rats during ethanol withdrawal. We did observe differential effects on brain allopregnanolone and plasma corticosterone levels between ethanol dependent intact and ovariectomized female rats, suggesting that ovarian steroids influence HPA axis adaptations to prolonged ethanol exposure. Overall, these data suggest that ovarian steroids do not significantly impact the gender selective alterations of GABA(A) and NMDA receptors associated with ethanol dependence.

Enhanced levels of wild-type versus mutant thyroid hormone receptor beta 1 messenger RNA in fibroblasts from heterozygotes of kindred S with thyroid hormone resistance.

Thyroid hormone resistance syndromes, which result from heterozygous mutations in the beta 1 thyroid hormone receptor gene, are sometimes associated with adult short stature, but more frequently with delayed bone age (BA). Primary fibroblasts from young children with both delayed BA and short stature from a kindred A have been reported to overexpress the mutant allele. However, in fibroblasts from affected members of two different kindreds with thyroid hormone resistance, S and Mf, there were equal levels of mutant and wild-type beta 1 mRNA. We investigated the ontogeny of differential allelic expression using competitive reverse transcription with PCR (RT-PCR) to measure relative mRNA levels for beta 1 and S receptor in very young affected children of kindred S. Total RNA was prepared from fibroblasts of two patients (ages 3-0.5/12 and 1-4/12 years) with delayed BA but normal growth curves. Using PCR amplimers that create an Mlu-1 site in wild-type but not mutant cDNA products from the competitive RT, we quantitated mRNA levels. Normal beta 1 mRNA was present at nearly twice the level of the mutant mRNA in cells from these patients. Relative expression of the c-erbA beta alleles thus appeared to be increased during this period of somatic growth. The relative overexpression of the normal allele potentially counteracted the potent dominant negative effect of the S receptor during early childhood ameliorating a deleterious effect on linear growth.

Induction and decline of hepatic cytochromes P4501A1 and 1A2 in rats exposed to hyperoxia are not paralleled by changes in glutathione S-transferase-alpha.

We investigated the effects of hyperoxia on the activities of hepatic ethoxyresorufin O-deethylase (EROD) (CYP1A1), methoxyresorufin O-demethylase (MROD) (CYP1A2), and glutathione transferase-alpha (GST-alpha), and the status of protein thiols (PSH) in male Sprague-Dawley rats. Twenty-four h of hyperoxia more than doubled EROD and MROD activities, which were increased 7.6- and 3.3-fold, respectively, after 48 h of hyperoxia. The increases in EROD and MROD activities were paralleled by enhanced CYP1A1/1A2 apoproteins contents, as detected by Western analysis. At 60 h of hyperoxia, by which time hyperoxic Sprague-Dawley rats display marked respiratory distress, pulmonary edema, and other markers of pulmonary dysfunction, the activities and levels of hepatic CYP1A1 and 1A2 had declined dramatically and returned to levels observed in air-breathing control animals. Hepatic activities of GST-alpha, as well as PSH status, were not altered significantly in the hyperoxic animals at any time point. The marked induction and subsequent decline of hepatic CYP1A1/1A2 activities in rats exposed to hyperoxia suggest that these enzymes may contribute to the mechanisms of injury and/or to adaptive responses to hyperoxic exposures in vivo.

Risk profiles for non-communicable diseases in rural and urban schoolchildren in the Republic of Cameroon.

OBJECTIVES: In developing countries, there is evidence that the median age of the population and the life expectancy at birth are increasing as a result of decreasing fertility rates and infant mortality. The result is an aging population more prone to non-communicable diseases such as diabetes, cancer, or heart disease later in life. In addition, changing lifestyle factors such as tobacco use, physical inactivity, and high fat diets, may accelerate the emergence of such chronic diseases as major causes of death and disability in these countries, particularly in urban areas. To test the premise that urban living predisposes residents to reduced activity levels, less healthy diets, cigarette smoking, elevated blood pressure, and increased body fat early in life, we studied rural/urban differences in these risk factors among schoolchildren in the Republic of Cameroon. METHODS: One hundred and nineteen Class 7 schoolchildren (50 urban and 69 rural) were interviewed concerning diet, physical activity, smoking, and alcohol use; blood pressure and anthropometric measurements were also taken. RESULTS: Physical activity among rural children was more than twice that of urban children, and most of the activity for rural children was work-related. Rural children consumed fewer foods containing fat and more fruits and vegetables. Adjusting for age, systolic and diastolic blood pressures of urban boys were higher than those of rural boys, and among urban children there was a trend toward a larger age-adjusted mean body mass index (BMI). There were no differences in alcohol or tobacco use between urban and rural children. CONCLUSIONS: In this study, urbanization was associated with a less active lifestyle and a dietary pattern that was higher in fat and lower in fruit and vegetable intake. Since risk factors for non-communicable diseases tend to appear early in life and track into adulthood, it is important to identify those children, or groups of children, with unfavorable risk profiles and to structure health education and promotion programs to modify these trends.