Body metrics are associated with clinical, free-living, and self-report measures of mobility in a cohort of adults with obesity and multiple sclerosis.

BACKGROUND: Obesity is associated with multiple sclerosis (MS) onset and may contribute to more rapid disability accumulation. Whether obesity impacts mobility in MS is uncertain. Some studies find that obesity in MS is associated with poorer mobility; other studies find no relationship. Discrepant findings may be due to differences in measurement and methodology. In the present study, we employ a comprehensive battery of anthropometric and mobility measures in a sample of people with MS and obesity. METHODS: Participants with MS (N = 74) completed a battery of adiposity measurements (weight, height, waist circumference, and full body dual-energy x-ray absorptiometry [DXA] scans). They also completed validated clinical, free-living (accelerometry), and self-report measures of mobility. Spearman's Rho correlations were used to examine the associations between mobility and obesity measures with Benjamini and Hochberg correction for multiple comparisons. Multiple linear regression was used to examine if adiposity predicted mobility outcomes in people with MS when controlling for age and disease duration. RESULTS: The majority of participants (n = 70) were diagnosed with relapsing-remitting MS and reported mild MS-related disability on the Patient Determined Disease Steps (M = 0.77, SD = 1.1). Median BMI was 35.8 (SD = 5.4). Higher percentage body fat (measured via DXA) was associated with poorer self-reported physical functioning (rs = -0.52, p <0.001), less moderate-to-vigorous physical activity (rs = -0.24, p = 0.04), and worse performance on the Six Minute Walk Test (6MWT; rs = -0.44, p <0.001), the Timed 25 Foot Walk (T25FW; rs = 0.45, p <0.001), and the Timed Up and Go test (TUG; rs = 0.35, p = .003). Higher BMI and waist-to-height ratio (WtHR) were associated with worse outcomes on the 6MWT (BMI; rs = -0.35, p <0.01, WtHR; rs = -0.43, p <0.001), T25FW (BMI; rs = 0.32, p <0.01, WtHR; rs = 0.38, p <0.001), and the SF-36 (BMI; rs = -0.29, p <0.005, WtHR; rs = -0.31, p <0.05). Percentage body fat accounted for an additional 17 % of the variance in the T25FW and 6MWT performance, after controlling for age and disease duration. CONCLUSION: Higher BMI, WtHR, and percentage body fat were associated with lower levels of mobility (T25FW and 6MWT) in people with MS who have class I, class II, and class III obesity. Higher percentage body fat was associated with significantly worse performance on clinical, free-living, and self-report measures of mobility in people with MS even when accounting for participant age and disease duration. These findings suggest that people with MS and obesity may show improved mobility with weight loss.

Patient function in serial assessments throughout the post-ACL reconstruction progression.

OBJECTIVE: To assess the changes in patient strength and function from 4- to 6-month assessments following ACLR, determine relationships between changes in strength to changes in subjective function, and identify factors that predict patients that fail to increase in strength. DESIGN: Prospective, Cohort Study. SETTING: Controlled Laboratory. PARTICIPANTS: Forty-seven patients(27 female, 24.3 ± 11.1 years) completed a battery of performance assessments at approximately 4- and 6-months following primary ACLR (4.03 ±0 .49 and 6.46 ±0 .68 months). MAIN OUTCOME MEASURES: Subjective scores and isokinetic knee flexor and extensor strength were compared across visits. Patients were categorized per their ability to increase in strength beyond a previously defined threshold(0.22 Nm/kg). Binary logistic regression models were used to determine predictors of patients that failed to meet strength changes. RESULTS: Patients demonstrated improvements in patient-reported outcomes and strength measures between visits(P's < 0.05). Higher age (B = -0.073, P = .039), lower pre-injury activity levels (B = 0.61, P = .022), and higher limb symmetry indexes (B = -0.044, P = .05) at 4-months were predictors of patients that did not achieve improvements in quadriceps strength between assessments. CONCLUSIONS: From 4- to 6-months post-ACLR, increases in subjective function, strength and symmetry were observed. High quadriceps symmetry at interim assessments without consideration of the magnitude of strength values could overestimate recovery of quadriceps function.

Importance of reward and prefrontal circuitry in hunger and satiety: Prader-Willi syndrome vs simple obesity.

BACKGROUND: The majority of research on obesity (OB) has focused primarily on clinical features (eating behavior, adiposity measures) or peripheral appetite-regulatory peptides (leptin, ghrelin). However, recent functional neuroimaging studies have demonstrated that some reward circuitry regions that are associated with appetite-regulatory hormones are also involved in the development and maintenance of OB. Prader-Willi syndrome (PWS), characterized by hyperphagia and hyperghrelinemia reflecting multi-system dysfunction in inhibitory and satiety mechanisms, serves as an extreme model of genetic OB. Simple (non-PWS) OB represents an OB-control state. OBJECTIVE: This study investigated subcortical food motivation circuitry and prefrontal inhibitory circuitry functioning in response to food stimuli before and after eating in individuals with PWS compared with OB. We hypothesized that groups would differ in limbic regions (that is, hypothalamus, amygdala) and prefrontal regions associated with cognitive control (that is, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC) after eating. DESIGN AND PARTICIPANTS: A total of 14 individuals with PWS, 14 BMI- and age-matched individuals with OB, and 15 age-matched healthy-weight controls viewed food and non-food images while undergoing functional MRI before (pre-meal) and after (post-meal) eating. Using SPM8, group contrasts were tested for hypothesized regions: hypothalamus, nucleus accumbens (NAc), amygdala, hippocampus, OFC, medial PFC and DLPFC. RESULTS: Compared with OB and HWC, PWS demonstrated higher activity in reward/limbic regions (NAc, amygdala) and lower activity in the hypothalamus and hippocampus in response to food (vs non-food) images pre-meal. Post meal, PWS exhibited higher subcortical activation (hypothalamus, amygdala, hippocampus) compared with OB and HWC. OB showed significantly higher activity versus PWS and HWC in cortical regions (DLPFC, OFC) associated with inhibitory control. CONCLUSION: In PWS, compared with OB per se, results suggest hyperactivations in subcortical reward circuitry and hypoactivations in cortical inhibitory regions after eating, which provides evidence of neural substrates associated with variable abnormal food motivation phenotypes in PWS and simple OB.

Obese children show hyperactivation to food pictures in brain networks linked to motivation, reward and cognitive control.

OBJECTIVE: To investigate the neural mechanisms of food motivation in children and adolescents, and examine brain activation differences between healthy weight (HW) and obese participants. SUBJECTS: Ten HW children (ages 11-16; BMI < 85%ile) and 10 obese children (ages 10-17; BMI >95%ile) matched for age, gender and years of education. MEASUREMENTS: Functional magnetic resonance imaging (fMRI) scans were conducted twice: when participants were hungry (pre-meal) and immediately after a standardized meal (post-meal). During the fMRI scans, the participants passively viewed blocked images of food, non-food (animals) and blurred baseline control. RESULTS: Both groups of children showed brain activation to food images in the limbic and paralimbic regions (PFC/OFC). The obese group showed significantly greater activation to food pictures in the PFC (pre-meal) and OFC (post-meal) than the HW group. In addition, the obese group showed less post-meal reduction of activation (vs pre-meal) in the PFC, limbic and the reward-processing regions, including the nucleus accumbens. CONCLUSION: Limbic and paralimbic activation in high food motivation states was noted in both groups of participants. However, obese children were hyper-responsive to food stimuli as compared with HW children. In addition, unlike HW children, brain activations in response to food stimuli in obese children failed to diminish significantly after eating. This study provides initial evidence that obesity, even among children, is associated with abnormalities in neural networks involved in food motivation, and that the origins of neural circuitry dysfunction associated with obesity may begin early in life.

A treatment algorithm for mass heat casualties.

Although thankfully rare,heat related illness has significant implications for the effective fighting force available to commanders. This is especially pertinent in the current theatres of operations, as previously soldiers have not routinely been subjected to the rigors of operating in hot climates. In addition to Iraq and Afghanistan, various training exercises are undertaken throughout the world where extreme temperatures may be encountered. Individual medical officers may be faced with heat casualties remote from all but the most basic facilities or the number of heat casualties may overwhelm limited resources. We present a simple treatment algorithm that has been used successfully in the treatment of mass heat casualties.

Should the tibia be reamed when nailing?

A systematic review was performed to assess reamed and unreamed tibial nailing. Only prospective, randomised studies comparing reamed and unreamed tibial nailing in adults were included. A literature search found 1200 possible articles. There were seven comparative studies. These articles were independently assessed by all three authors. Three studies met the inclusion criteria. Each outcome measure tested was assessed for heterogeneity. If significant heterogeneity was present, data from the studies was not combined. If there was no significant heterogeneity, a combined odds ratio was calculated using a fixed effects model and a Z-test was performed to test the overall effect. Two hundred and ninety-one tibial shaft fractures were entered into the included studies. Two hundred and eighty (96%) were followed up (148 reamed; 132 unreamed). There was an increased non-union rate when the tibia was not reamed (p = 0.02). Screw breakage was more common in the unreamed group (p<0.0001). This study could find little difference in the incidence of other complications following reamed or unreamed tibial nailing.

The effect of the ankle brachial pressure index and the use of a tourniquet upon the outcome of total knee replacement.

Current teaching suggests that patients requiring a total knee arthroplasty who have absent pulses or an abnormal ankle-brachial pressure index (ABPI) should be referred for vascular investigation. The aim of this study was to determine whether total knee arthroplasty was safe in such patients. The ABPI was measured with a hand-held Doppler. Patients were excluded if they had active ulceration, rest pain, or an absent femoral pulse, but patients with claudication were included. A total of 73 patients were recruited. Hand-held Doppler detected signals from 98% of arteries. Postoperatively, there were no signs of limb ischemia, and the median ABPIs increased significantly. From our series, it seems safe to proceed with surgery in patients with impalpable foot pulses or claudication, as long as the femoral pulse is palpable and there is no active ulceration or rest pain.

Analysis of tear film breakup on Etafilcon A hydrogel lenses.

PURPOSE: There is a need to understand better the biomaterial characteristics responsible for tear film stability during hydrogel lens wear. The underlying cause of pre-lens tear film instability may be indicated by the distribution of sites of breakup. The purpose of this study was to compare the distribution of rupture sites during wear of a common biomaterial to that without lenses. METHODS: A videokeratography unit, the Topographic Modeling System, was used to capture an image of the tear film at the moment of breakup. Forty measurements were made for each of ten subjects, and the resultant rupture site distributions evaluated. The pre-lens tear film breakup locations were studied for Acuvue (Etafilcon A) disposable contact lenses using the same technique. RESULTS: There was a statistically significant trend for pre-corneal tear film breaks to occur more commonly in parameniscal zones than in areas overlying the central cornea (ANOVA, p = 0.002). With the Etafilcon A lenses, a significant difference in breakup frequency between the two regions was not observed. CONCLUSIONS: The pre-corneal tear film findings are consistent with the meniscus model of tear film stability; however, the biomaterial surface characteristics of Etafilcon A give other factors a more dominant role in tear film rupture.

The conjunctival epithelium in dry eye subtypes: effect of preserved and non-preserved topical treatments.

PURPOSE: To determine the effect of topical treatments on the conjunctiva in dry eye. METHODS: N = 134 dry eye subjects were diagnosed using a protocol of McMonnies dry eye symptom survey score > 14, fluorescein break up time (FBUT) < 10 s and presence of rose Bengal staining. Differential diagnosis of dry eye subtypes was based on biomicroscopic signs and ocular/medical history. Superficial perilimbal bulbar conjunctival epithelial samples were collected using impression cytology. The nucleo-cytoplasmic ratio (N/C), goblet cell density (GCD) and expression of monoclonal antibodies HLA DR and CD23 were determined. The ocular surface characteristics of untreated subjects, those receiving preserved dry eye treatments and those receiving non-preserved treatments were compared with each other and with controls. Ocular surface characteristics of dry eye subtypes were also examined. RESULTS: An increase in N/C (p = 0.011), reduction in GCD (p = 0.0001) and increase in expression of HLA DR (p = 0.0001) and CD23 (p = 0.0001) were detected in the untreated group compared to controls. No significant differences were found between the group receiving non-preserved dry eye treatments and untreated dry eye group. The group receiving preserved treatments had a reduced GCD (p = 0.0003) and increased expression of HLA DR (p = 0.0003) and CD23 (p = 0.0001) compared to the group receiving non-preserved treatments. Dry eye subtype specific differences in HLA DR and CD23 expression were noted. CONCLUSIONS: The conjunctival inflammation and reduced goblet cell density of dry eye is exacerbated by use of preserved topical agents, and is not significantly improved by use of non-preserved artificial tear supplements alone. Therapeutic strategies for dry eye should aim to increase goblet cell density and control ocular surface inflammation.

Fluconazole-impregnated beads in the management of fungal infection of prosthetic joints.

We report two cases of fungal infection of prosthetic joints which were successfully treated by the incorporation of fluconazole into polymethylmethacrylate beads inserted at the time of debridement.

Keratoconus associated with continual eye rubbing due to punctal agenesis.

PURPOSE: To highlight a possible causal effect of eye rubbing in the etiology of keratoconus. METHODS: A 43-year-old man presented to the practice of one of the authors (I.F.G.) with the complaint of gradual onset reading difficulty. History revealed the patient to have experienced constant epiphora in the right eye throughout his life as a result of punctal agenesis, which necessitated frequent wiping of this eye. Vision in the patient's right eye had been reduced for approximately 20 years. RESULTS: Based on ocular examination, the patient was diagnosed as having unilateral keratoconus in the right eye. CONCLUSION: It is thought by some that keratoconus is associated with, or indeed caused by, persistent rubbing of the anterior eye. While a number of studies support a genetic basis for keratoconus in some patients, it is possible that mechanical factors play a role in the development of this condition in other patients. This paper presents a case of unilateral keratoconus, where there is a confirmed history of habitual eye rubbing and wiping of excess tears as a result of punctal agenesis in the ipsilateral eye, thereby suggesting a possible causal relationship of eye rubbing in the etiology of keratoconus.

Morphological variants in keratoconus: anatomical observation or aetiologically significant?

PURPOSE: Two morphological cone variants are identified in keratoconus; nipple and oval. The present study was designed to assess the impact of aetiological factors on cone morphology. METHODS: As part of a prospective controlled study, keratoconic subjects from a suburban practice (n = 89) underwent videokeratograph examination and completed a questionnaire detailing aetiological factors. RESULTS: Comparison of 95% confidence limits (CL; bootstrap method) for apical power between the two cone morphology groups showed no statistical significance. Oval cones were located at a greater eccentricity than nipple cones, as their definitions suggest. Associations between aetiological factors examined and the morphology of the cone were not significant (bootstrapped 95% CL). CONCLUSION: Despite the suggestion of morphological variants in keratoconus, the results of the present study suggest a common cone aetiology.

Relationship between tear-meniscus parameters and tear-film breakup.

PURPOSE: Several flaws exist with the lipid-diffusion model for tear-film breakup. The aim of this study was to test an alternative model of tear-film rupture in which the negative hydrostatic pressure in each tear meniscus (related to the tear-meniscus radius of curvature) is proposed to influence the formation of breaks in the tear film. METHODS: Measurements of noninvasive breakup time (NIBUT) and tear-meniscus radius of curvature, height, width, and cross-sectional area (TMC, TMH, TMW, and XSA) were made for 15 aqueous-deficient dry-eye and 15 age-matched control subjects. An optic section of the inferior tear meniscus (colored with a minute volume of fluorescein) was photographed at x120 magnification, and images were computer analyzed. RESULTS: A significant positive correlation was found between log NIBUT and TMC (r2 = 0.141; p < 0.05). Furthermore, all subjects with TMC < 0.340 mm had NIBUT < 15 s, and two thirds of subjects with TMC > 0.340 mm had NIBUT > 15 s. There was a moderate linear relationship between TMH and log NIBUT, indicating an association between tear volume and tear stability. TMC, TMH, and tear meniscus XSA measurements all showed good reliability. CONCLUSIONS: The association between highly curved tear menisci and rapid tear-film breakup times is consistent with the meniscus model of tear-film rupture. However, a causal relationship has yet to be established.

Tear meniscus measurement in the diagnosis of dry eye.

PURPOSE: Assessment of the tear film meniscus is a quantitative, minimally invasive, direct measurement of tear film quantity. The aim of this study was to assess the efficacy of tear meniscus parameter measurement in the diagnosis of dry eye. METHODS: Tear meniscus radius of curvature, height, width and cross-sectional area (TMC, TMH, TMW, XSA) were determined by photographing an optic section of the inferior tear meniscus (colored with a min volume of fluorescein) at 12 x magnification, and then scanning developed images into a computer analysis program. Fifteen dry eye subjects and 15 age-matched controls were assessed. Dry eye subjects satisfied the criteria of a rose bengal staining score >/= 1, and a mean phenol red thread 15s wetted length

Lens adherence and postlens tear film changes in closed-eye wear of hydrogel lenses.

BACKGROUND: Lens adherence and a reduced postlens tear film circulation have been suggested as factors contributing to some adverse reactions in extended wear of hydrogel contact lenses. In this study, we determined lens fitting and postlens tear film characteristics during closed-eye wear. METHODS: Twenty subjects wore hydrogel lenses for 3 h of eye closure, followed by 30 min of open-eye wear. Lens movement was measured with a video biomicroscope. Postlens tear film appearances in specular reflection were classified as either amorphous, or as one of four color intensity grades, where a colored appearance was taken as indicative of a depleted postlens tear film. RESULTS: All subjects showed lens adherence (movement < 0.1 mm) and postlens tear film depletion within 45 min of eye closure. These changes were sustained for the remainder of the closed-eye period, but were reversed within 15 min of eye opening. Lens adherence was associated with colored postlens tear film patterns of any intensity. CONCLUSION: Closed-eye wear was invariably associated with the onset of lens adherence and postlens tear film depletion. This finding emphasizes the need for adequate lens movement during the open-eye phase of extended wear.

Soft lens movement: effect of blink rate on lens settling.

Little is understood about the mechanism by which soft lenses settle on the eye, although it has been suggested that lens base curve, steepening with in-eye lens dehydration or tear film changes may influence lens movement in the initial period of wear. In this study, we investigated the role of postlens tear fluid expulsion by assessing lens movement in 20 subjects wearing 38% water content hydrogel lenses for 10 min under three different conditions: 10 blinks/min, 30 blinks/min and eye closure. Over the 10 min wearing period, the total decrease in median lens movement for the 10 blinks/min condition was 0.07 mm, which was not a significant change (Friedman ANOVA, p = 0.13), while significant decreases occurred with conditions of 30 blinks/min (0.19 mm, p = 0.004) and eye closure (0.43 mm, p = 0.0001). As expected, lens movement under the three conditions was the same at insertion, but was significantly higher thereafter for the slower blink rate condition compared to the faster blink rate or eye closure conditions (Wilcoxon test, Z = 2.8 and -3.0, p = 0.006 and 0.003, respectively). Based on these findings, we postulate the model that the extent of lens settling and the degree of postinsertion lens movement are determined by the timeaverage pressure for postlens tear film expulsion exerted on the lens by the eyelids.

Role of the post-lens tear film in the mechanism of inferior arcuate staining with ultrathin hydrogel lenses.

We studied the depletion of the post-lens tear film as contributing to inferior arcuate staining with ultrathin high water content hydrogel lenses. We monitored the post-lens tear film specular reflection of hydrogel lenses (0.04 mm center thickness, 67% nominal water content), which caused inferior arcuate staining. A standard thickness (0.12 mm) lens was worn in the contralateral eye as a control condition. Lenses were worn for a 2 hour period by 20 subjects. Post-lens tear film appearances were categorized as amorphous, faint colored, or colored, where the colored patterns represented a relatively depleted post-lens tear film. We also measured lens dehydration, lens adherence, and pre-lens tear film stability in order to evaluate their role in inferior arcuate staining. The ultrathin and standard lenses caused staining in 100 and 75% of subjects, respectively; the severity of staining was much greater with the ultrathin lenses (Wilcoxon signed ranks test, P = 0.0004). The ultrathin lenses were associated with a higher incidence of post-lens tear film depletion (P = 0.018), had greater front surface dehydration (P = 0.0004), and were more adherent to the eye (paired t-test, P = 0.001). However, pre-lens tear thinning times were not significantly different between the two lens types (Wilcoxon signed ranks test, P > 0.05). These findings support the contention that post-lens tear film depletion is a component of a lens adherence or lens dehydration mediated mechanism of inferior arcuate staining.

Osmotic determinants of postlens tear film morphology and hydrogel lens movement.

The determinants of postlens tear film (PTF) composition in hydrogel lens wear are poorly understood, although this layer has important roles in lens movement and corneal integrity. We investigated the hypothesis that the PTF could be depleted by instillation of hypotonic saline, using a randomized, double masked, placebo controlled study design. Solutions of 0.90, 0.60 and 0.45% NaCl were instilled into the eyes of 12 subjects wearing ionic and non-ionic high water content hydrogel lenses. Postlens tear film appearances in specular reflection were categorized as amorphous, faint coloured or coloured, where the coloured patterns represent a progressive thinning of the PTF. With instillation of the hypotonic solutions (0.60 and 0.45% NaCl), the appearance of the PTF in specular reflection changed to a faint coloured or coloured pattern in at least 67% of subjects for each lens type (Friedman ANOVA, P < 0.002). For the 0.45% NaCl solution, median lens movement decreased from 0.50 to 0.10 mm (Friedman ANOVA, P = 0.02); however, there were no significant changes in measured lens parameters and no difference between lens types. Postlens tear film depletion due to a hypotonic shift in tear osmolality, as demonstrated here, may explain the clinically observed phenomenon of lens binding.

Accommodation-convergence relationships and age.

PURPOSE: The objective of this study was to determine if there are differences in accommodative-convergence/accommodation (AC/A) and convergence-accommodation/convergence (CA/C) ratios in subjects with increasing age. The authors aimed to relate the findings to the present theories of the development of presbyopia. METHODS: Using a Canon AutoRef R-1 to measure accommodation and an IRIS eye movement monitor to measure eye movements, the authors determined objective AC/A and CA/C ratios for 23 subjects between 17 and 42 years of age with normal binocular vision. Changes in accommodation and convergence responses were stimulated by lenses (-1.00 DS and -2.00 DS) and prisms (4 and 8 prism diopters), respectively. Measures were made at two visits on consecutive days. RESULTS: A moderate linear relationship was found between AC/A ratio and age (P < .002), and a strong linear relationship was found between CA/C ratio and age (P < .0001). The decrease in CA/C ratio with age was due to a decreased accommodative response to prisms (P = .0001). Measurements were reliable, with 95% confidence intervals at +/- 1.28 delta/D and +/- 0.02 D/delta for AC/A and CA/C ratios, respectively. A reciprocal relationship existed between the AC/A and CA/C ratios. CONCLUSION: The AC/A ratio increases, and the CA/C ratio decreases, in persons between 20 and 40 years of age. This may be because increasing ciliary muscle contraction is required to produce a given change in accommodation with increasing age or because of changes in the adaptability of the tonic accommodation and vergence systems with age.