Prevalence of smoking in the United States: A focus on age, sex, ethnicity, and geographic patterns

Over the last 40 years, the prevalence of smoking in the United States has declined from a peak of approximately 40% in 1965 to 20.9% in 2005. However, the rate of decline has leveled in recent years such that between 2004 and 2005 there was no decline in smoking prevalence. The prevalence of smoking varies across subpopulations. Among adults, smoking prevalence is currently highest among those aged 18 to 24 years (24.4%) and those aged 25 to 44 years (24.1%). Women are less likely to smoke than men; however, the gender gap has narrowed over time. In immigrant populations, smoking prevalence increases with acculturation. Although smoking prevalence varies widely by state, most states have had a decline over time. Rural populations have a higher smoking prevalence than urban populations. If further reductions in the prevalence of smoking are to occur, vigilance and targeted interventions in specific subpopulations will be crucial.     

Association of DLG5 R30Q variant with inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal system known as the inflammatory bowel diseases (IBD). Recently, Stoll and colleagues reported a novel finding of genetic variation in the DLG5 gene that is associated with IBD (CD and UC combined). We present here a study of the genetic variation described in that report in two well-powered, independent case-control cohorts and one family-based collection, and confirm the proposed association between IBD and the R30Q variant of DLG5 in two of the three studies. We are, however, unable to replicate the other proposed association to the common haplotype described in Stoll et al and suggest that this other finding could conceivably have been partially a statistical fluctuation and partially a result of LD with the replicated R30Q association. This study provides support for the hypothesis that DLG5 constitutes a true IBD risk factor of modest effect.     

Hypoxia and glucose metabolism in malignant tumors: evaluation by [18F]fluoromisonidazole and [18F]fluorodeoxyglucose positron emission tomography imaging.

PURPOSE: The aim of this study is to compare glucose metabolism and hypoxia in four different tumor types using positron emission tomography (PET). (18)F-labeled fluorodeoxyglucose (FDG) evaluates energy metabolism, whereas the uptake of (18)F-labeled fluoromisonidazole (FMISO) is proportional to tissue hypoxia. Although acute hypoxia results in accelerated glycolysis, cellular metabolism is slowed in chronic hypoxia, prompting us to look for discordance between FMISO and FDG uptake. EXPERIMENTAL DESIGN: Forty-nine patients (26 with head and neck cancer, 11 with soft tissue sarcoma, 7 with breast cancer, and 5 with glioblastoma multiforme) who had both FMISO and FDG PET scans as part of research protocols through February 2003 were included in this study. The maximum standardized uptake value was used to depict FDG uptake, and hypoxic volume and maximum tissue:blood ratio were used to quantify hypoxia. Pixel-by-pixel correlation of radiotracer uptake was performed on coregistered images for each corresponding tumor plane. RESULTS: Hypoxia was detected in all four patient groups. The mean correlation coefficients between FMISO and FDG uptake were 0.62 for head and neck cancer, 0.47 for breast cancer, 0.38 for glioblastoma multiforme, and 0.32 for soft tissue sarcoma. The correlation between the overall tumor maximum standardized uptake value for FDG and hypoxic volume was small (Spearman r = 0.24), with highly significant differences among the different tumor types (P < 0.005). CONCLUSIONS: Hypoxia is a general factor affecting glucose metabolism; however, some hypoxic tumors can have modest glucose metabolism, whereas some highly metabolic tumors are not hypoxic, showing discordance in tracer uptake that can be tumor type specific.     

Weight-Bearing Dorsiflexion Range of Motion and Landing Biomechanics in Individuals With Chronic Ankle Instability

Context

People with chronic ankle instability (CAI) exhibit less weight-bearing dorsiflexion range of motion (ROM) and less knee flexion during landing than people with stable ankles. Examining the relationship between dorsiflexion ROM and landing biomechanics may identify a modifiable factor associated with altered kinematics and kinetics during landing tasks.

Objective

To examine the relationship between weight-bearing dorsiflexion ROM and single-legged landing biomechanics in persons with CAI.

Design

Cross-sectional study.

Setting

Laboratory.

Patients or Other Participants

Fifteen physically active persons with CAI (5 men, 10 women; age = 21.9 ± 2.1 years, height = 168.7 ± 9.0 cm, mass = 69.4 ± 13.3 kg) participated.

Intervention(s)

Participants performed dorsiflexion ROM and single-legged landings from a 40-cm height. Sagittal-plane kinematics of the lower extremity and ground reaction forces (GRFs) were captured during landing.

Main Outcome Measure(s)

Static dorsiflexion was measured using the weight-bearing–lunge test. Kinematics of the ankle, knee, and hip were observed at initial contact, maximum angle, and sagittal displacement. Sagittal displacements of the ankle, knee, and hip were summed to examine overall sagittal displacement. Kinetic variables were maximum posterior and vertical GRFs normalized to body weight. We used Pearson product moment correlations to evaluate the relationships between dorsiflexion ROM and landing biomechanics. Correlations (r) were interpreted as weak (0.00–0.40), moderate (0.41–0.69), or strong (0.70–1.00). The coefficient of determination (r²) was used to determine the amount of explained variance among variables.

Results

Static dorsiflexion ROM was moderately correlated with maximum dorsiflexion (r = 0.49, r² = 0.24), ankle displacement (r = 0.47, r² = 0.22), and total displacement (r = 0.67, r² = 0.45) during landing. Dorsiflexion ROM measured statically and during landing demonstrated moderate to strong correlations with maximum knee (r = 0.69–0.74, r² = 0.47–0.55) and hip (r = 0.50–0.64, r² = 0.25–0.40) flexion, hip (r = 0.53–0.55, r² = 0.28–0.30) and knee (r = 0.53–0.70, r² = 0.28–0.49) displacement, and vertical GRF (−0.47– −0.50, r² = 0.22–0.25).

Conclusions

Dorsiflexion ROM was moderately to strongly related to sagittal-plane kinematics and maximum vertical GRF during single-legged landing in persons with CAI. Persons with less dorsiflexion ROM demonstrated a more erect landing posture and greater GRF.Key Words: ankle sprain, drop landing, neuromuscular control, kinematics, kinetics

Key Points

• During a single-legged landing, persons with chronic ankle instability demonstrated moderate to strong relationships between dorsiflexion range of motion (ROM) and sagittal-plane kinematics at the knee and hip and vertical ground reaction forces.
• Persons with less dorsiflexion ROM exhibited a less flexed landing strategy that attenuated ground reaction forces less efficiently.
• Identifying dorsiflexion deficits may enable clinicians to implement interventions to increase ROM and potentially modify the landing biomechanics that persons with chronic ankle instability exhibit.

Ankle sprains are one of the most common injuries associated with athletics.¹ In addition, up to 73% of athletes who sustain ankle sprains experience recurrent ankle sprains, and 59% report functional loss and residual symptoms that have affected athletic performance.² Residual symptoms resulting from ankle sprains are often associated with a condition known as chronic ankle instability (CAI). This condition is characterized by repetitive ankle-sprain injuries, frequent episodes of the ankle “giving way,” and decreased self-reported function stemming from an acute ankle sprain.³ Persons with CAI have reported diminished health-related quality of life and are at greater risk for developing posttraumatic ankle osteoarthritis.^4,5 Based on the number of persons who develop CAI and the long-term consequences of the condition, a better understanding of the contributing factors is warranted to improve clinical intervention strategies.Chronic ankle instability may be associated with several mechanical impairments in ankle function,³ including a deficit in ankle-joint dorsiflexion range of motion (ROM).^3,6 Whereas the exact prevalence of dorsiflexion ROM deficits has not been determined, 30% to 74% of persons with CAI have at least a 5° deficit in weight-bearing dorsiflexion ROM compared with the contralateral limb.^7,8 The exact origin of dorsiflexion ROM deficits is unclear, but it likely results from arthrokinematic alterations and adaptive shortening of the triceps surae muscle group.^9,10 More importantly, dorsiflexion deficits may limit the ability to fully achieve a closed-packed, stable position of the ankle during dynamic activities, such as gait and landing, which may promote the pathomechanics associated with ankle-sprain mechanisms.^9,11,12 Therefore, a cascade of structural impairments leading to decreased dorsiflexion ROM may affect the ability to execute functional activities and ultimately contribute to the repeated ankle sprains and episodes of giving way related to CAI.Dorsiflexion ROM plays a prominent role in the biomechanics of tasks that require landing.¹³ Greater passive open chain dorsiflexion ROM has been associated with greater hip and knee flexion and lower ground reaction forces (GRFs) during a jump-landing task in healthy persons.¹³ Those with greater dorsiflexion ROM land with a less erect posture by using greater sagittal-plane displacement, which allows the body to attenuate forces more efficiently.¹³ Therefore, the available amount of dorsiflexion ROM may influence function not only at the ankle but also at more proximal structures in the lower extremity. Persons with CAI have demonstrated less dorsiflexion ROM during gait^11,14 and less knee flexion during landing than persons without CAI, but these findings have not been consistent in the literature.^15,16 Furthermore, persons with CAI have shown greater energy dissipation at the ankle and less energy dissipation at the knee.¹⁷ Cumulatively, these observations suggest that alterations exist in the distal to proximal linkage of the kinetic chain of the lower extremity in persons with CAI.¹⁷ Further examining a potential connection between dorsiflexion ROM and landing biomechanics may provide additional insight into these findings.Persons who have CAI and less dorsiflexion ROM may also exhibit more erect landing postures and greater GRF, which may have implications for sustaining future lower extremity injuries or episodes of giving way.^18,19 Examining this relationship may further support integrating clinical intervention strategies that target dorsiflexion ROM into the rehabilitation of persons with CAI.⁹ Therefore, the purpose of our study was to examine the relationship between dorsiflexion ROM and single-legged landing biomechanics in persons with CAI. We examined dorsiflexion ROM statically, using the weight-bearing–lunge test, and dynamically, using motion capture, to determine its relationship to landing biomechanics. In addition, we focused on the sagittal-plane kinematics of the lower extremity and GRFs to explore how dorsiflexion ROM may influence force attenuation in persons with CAI. Kinematics were examined in the sagittal plane because it is primarily responsible for force attenuation during landing tasks.²⁰ We hypothesized that persons with less dorsiflexion ROM would exhibit less sagittal-plane motion throughout the lower extremity and greater GRF during a single-legged drop-landing task.     

Optical molecular imaging detects changes in extracellular pH with the development of head and neck cancer

Noninvasive localized measurement of extracellular pH in cancer tissues can have a significant impact on the management of cancer. Despite its significance, there are limited approaches for rapid and noninvasive measurement of local pH in a clinical environment. In this study, we demonstrate the potential of noninvasive topical delivery of Alexa‐647 labeled pHLIP (pH responsive peptide conjugated with Alexa Fluor^® 647) to image changes in extracellular pH associated with head and neck squamous cell carcinoma using widefield and high resolution imaging. We report a series of preclinical analyses to evaluate the optical contrast achieved after topical delivery of Alexa‐647 labeled pHLIP in intact fresh human tissue specimens using widefield and high‐resolution fluorescence imaging. Using topical delivery, Alexa‐647 labeled pHLIP can be rapidly delivered throughout the epithelium of intact tissues with a depth exceeding 700 µm. Following labeling with Alexa‐647 labeled pHLIP, the mean fluorescent contrast increased four to eight fold higher in clinically abnormal tissues as compared to paired clinically normal biopsies. Furthermore, the imaging approach showed significant differences in fluorescence contrast between the cancer and the normal biopsies across diverse patients and different anatomical sites (unpaired comparison). The fluorescence contrast differences between clinically abnormal and normal tissues were in agreement with the pathologic evaluation. Topical application of fluorescently labeled pHLIP can detect and differentiate normal from cancerous tissues using both widefield and high resolution imaging. This technology will provide an effective tool to assess tumor margins during surgery and improve detection and prognosis of head and neck cancer.