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1.
World J Pediatr Congenit Heart Surg ; 15(2): 155-159, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38263637

ABSTRACT

BACKGROUND: Ebstein anomaly is a rare congenital anomaly of the tricuspid valve which presents challenges to cardiac surgeons due to the spectrum of the disease and the technical difficulty of valve repair. The natural history of the anomaly differs between patients presenting in the neonatal period to those presenting in adulthood. METHODS: A retrospective review of all patients >15 years of age with Ebstein anomaly, undergoing surgery on the tricuspid valve at 6 centers across Australia and New Zealand was performed. Patients from 1985 to 2019 were included in the study. RESULTS: A total of 125 patients were included in the study, 76 patients (60%) undergoing tricuspid valve repair, of which 23 patients underwent a Cone repair and 49 (40%) had a tricuspid valve replacement. The mean follow-up was 7.9 ± 7.3 years. Postoperatively, early mortality was 3 patients (2%) and 10-year survival was 91.5%. A postoperative pacemaker was required in 24 patients (19%). Reoperation was required in 21 patients (17%). There was no statistically significant difference in survival or reoperation between patients who underwent repair or replacement of the tricuspid valve; however, with a small number of patients in long-term follow-up. CONCLUSION: Older children and adult patients undergoing surgery for Ebstein anomaly in Australia and New Zealand experience good medium-term postoperative survival. Repair of the valve is achieved in a significant proportion of patients with increasing use and success with the Cone repair technique.


Subject(s)
Ebstein Anomaly , Child , Infant, Newborn , Adult , Humans , Adolescent , Ebstein Anomaly/surgery , New Zealand , Treatment Outcome , Tricuspid Valve/surgery , Australia
2.
bioRxiv ; 2023 Oct 16.
Article in English | MEDLINE | ID: mdl-37905058

ABSTRACT

Force-length (F-L) and force-velocity (F-V) properties characterize skeletal muscle's intrinsic properties under controlled conditions, and it is thought that these properties can inform and predict in vivo muscle function. Here, we map dynamic in vivo operating range and mechanical function during walking and running, to the measured in situ F-L and F-V characteristics of guinea fowl (Numida meleagris) lateral gastrocnemius (LG), a primary ankle extensor. We use in vivo patterns of muscle tendon force, fascicle length, and activation to test the hypothesis that muscle fascicles operate at optimal lengths and velocities to maximize force or power production during walking and running. Our findings only partly support our hypothesis: in vivo LG velocities are consistent with optimizing power during work production, and economy of force at higher loads. However, LG does not operate at lengths on the force plateau (±5% Fmax) during force production. LG length was near L0 at the time of EMG onset but shortened rapidly such that force development during stance occurred almost entirely on the ascending limb of the F-L curve, at shorter than optimal lengths. These data suggest that muscle fascicles shorten across optimal lengths in late swing, to optimize the potential for rapid force development near the swing-stance transition. This may provide resistance against unexpected perturbations that require rapid force development at foot contact. We also found evidence of passive force rise (in absence of EMG activity) in late swing, at lengths where passive force is zero in situ, suggesting that dynamic history dependent and viscoelastic effects may contribute to in vivo force development. Direct comparison of in vivo work loops and physiological operating ranges to traditional measures of F-L and F-V properties suggests the need for new approaches to characterize dynamic muscle properties in controlled conditions that more closely resemble in vivo dynamics.

3.
Integr Comp Biol ; 2022 May 24.
Article in English | MEDLINE | ID: mdl-35612979

ABSTRACT

Navigating complex terrains requires dynamic interactions between the substrate, musculoskeletal and sensorimotor systems. Current perturbation studies have mostly used visible terrain height perturbations, which do not allow us to distinguish among the neuromechanical contributions of feedforward control, feedback-mediated and mechanical perturbation responses. Here, we use treadmill belt speed perturbations to induce a targeted perturbation to foot speed only, and without terrain-induced changes in joint posture and leg loading at stance onset. Based on previous studies suggesting a proximo-distal gradient in neuromechanical control, we hypothesized that distal joints would exhibit larger changes in joint kinematics, compared to proximal joints. Additionally, we expected birds to use feedforward strategies to increase the intrinsic stability of gait. To test these hypotheses, seven adult guinea fowl were video recorded while walking on a motorized treadmill, during both steady and perturbed trials. Perturbations consisted of repeated exposures to a deceleration and acceleration of the treadmill belt speed. Surprisingly, we found that joint angular trajectories and center of mass fluctuations remain very similar, despite substantial perturbation of foot velocity by the treadmill belt. Hip joint angular trajectories exhibit the largest changes, with the birds adopting a slightly more flexed position across all perturbed strides. Additionally, we observed increased stride duration across all strides, consistent with feedforward changes in the control strategy. The speed perturbations mainly influenced the timing of stance and swing, with the largest kinematic changes in the strides directly following a deceleration. Our findings do not support the general hypothesis of a proximo-distal gradient in joint control, as distal joint kinematics remain largely unchanged. Instead, we find that leg angular trajectory and the timing of stance and swing are most sensitive to this specific perturbation, and leg length actuation remains largely unchanged. Our results are consistent with modular task-level control of leg length and leg angle actuation, with different neuromechanical control and perturbation sensitivity in each actuation mode. Distal joints appear to be sensitive to changes in vertical loading but not foot fore-aft velocity. Future directions should include in vivo studies of muscle activation and force-length dynamics to provide more direct evidence of the sensorimotor control strategies for stability in response to belt speed perturbations.

4.
Phys Fluids (1994) ; 33(3): 037122, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33897243

ABSTRACT

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world.

5.
Eur J Trauma Emerg Surg ; 43(1): 105-111, 2017 Feb.
Article in English | MEDLINE | ID: mdl-26888580

ABSTRACT

PURPOSE: The purpose of this study is to determine if adenosine diphosphate (ADP) platelet dysfunction on thromboelastogram (TEG) is associated with increased in-hospital mortality in patients with head trauma. The hypothesis is that ADP dysfunction is associated with increased mortality. METHODS: This retrospective review evaluated trauma patients admitted to a level 1 trauma center from February 2011 to October 2013 who received a TEG. Patients were included if the TEG was drawn within the first 24 h of admission and the head abbreviated injury score was greater than or equal to three. Patients were categorized as severe ADP dysfunction if the degree of ADP inhibition on TEG exceeded 60 %. RESULTS: A total of 90 patients were included (no ADP dysfunction n = 37; ADP dysfunction n = 53). Initial Glasgow Coma Scale [GCS (12 ± 4 vs. 11 ± 5; p = 0.26)] and use of pre-injury antiplatelet agents (30 vs. 28 %; p = 0.88) were similar. Patients with ADP dysfunction on TEG had a higher in-hospital mortality rate (8 vs. 32 %; p < 0.01). ADP dysfunction was independently associated with in-hospital mortality upon fixed logistic regression (OR 6.2; 95 % CI 1.2-33) while controlling for age, gender, hypotension, pre-injury antiplatelet agents, GCS and Injury Severity Score. CONCLUSION: ADP dysfunction on TEG is associated with increased mortality in patients with traumatic brain injury.


Subject(s)
Adenosine Diphosphate/blood , Blood Platelets/physiology , Brain Injuries, Traumatic/blood , Brain Injuries, Traumatic/mortality , Hospital Mortality , Thrombelastography , Aged , Female , Glasgow Coma Scale , Humans , Injury Severity Score , Male , Platelet Function Tests , Retrospective Studies
6.
HIV Med ; 18(2): 125-132, 2017 02.
Article in English | MEDLINE | ID: mdl-27478058

ABSTRACT

OBJECTIVES: The aim of the study was to describe the characteristics of HIV-infected late presenters, opportunistic diseases at diagnosis and missed opportunities to diagnose HIV infection earlier. METHODS: In a retrospective cohort study, we reviewed the medical records of all adults with newly diagnosed HIV infection admitted to the Department of Infectious Diseases of the Vivantes Auguste-Viktoria Hospital, Berlin, Germany. RESULTS: In the 5-year period from 2009 to 2013, 270 late presenters were identified. The most common AIDS-defining conditions were oesophageal candidiasis (n = 136; 51%), wasting syndrome (n = 106; 40%) and pneumocystis pneumonia (n = 91; 34%). Fifty-five patients (21%) had presented with at least one HIV indicator condition on prior contact with health care services without being offered testing for HIV. Female patients and heterosexual men [not men who have sex with men ('non-MSM')] had a significantly higher chance of being among patients previously presenting with indicator conditions and not being tested [odds ratio (OR) 4.7; 95% confidence interval (CI) 2.2-10.0; P < 0.001; and OR 2.4; 95% CI 1.2-5.1; P < 0.01, respectively]. The most commonly missed indicator conditions were leucocytopenia (n = 13; 24%), thrombocytopenia (n = 12; 22%), oral candidiasis (n = 9; 16%), unexplained weight loss (n = 7; 13%), herpes zoster (n = 5; 9%) and cervical dysplasia/cancer (n = 4; 20% of women). The median time between presentation with an indicator condition and the diagnosis of HIV infection was 158.5 days [interquartile range (IQR) 40-572 days]. Patients with oral candidiasis and unexplained weight loss had the shortest time between the "missed opportunity" and the diagnosis of HIV infection. Fifty-five hospital admissions with a total cost of over EUR 500 000 and - most importantly - six in-hospital deaths might have been prevented if HIV testing had been performed in patients with documented indicator conditions. CONCLUSIONS: Indicator conditions are still missed by clinicians. Women and 'non-MSM' are at highest risk of presenting with an indicator condition but not being tested for HIV infection.


Subject(s)
AIDS-Related Opportunistic Infections/epidemiology , HIV Infections/complications , HIV Infections/diagnosis , AIDS-Related Opportunistic Infections/pathology , Adult , Aged , Aged, 80 and over , Berlin , Delayed Diagnosis , Early Diagnosis , Female , Germany , Humans , Male , Middle Aged , Retrospective Studies
7.
Pediatr Obes ; 10(5): 371-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25612172

ABSTRACT

BACKGROUND: Although paediatric growth charts are recommended for weight assessment prior to age 20, many teenagers transition earlier to adult care where absolute body mass index (BMI) is used. This study examines concordance of weight classification in older teenagers using paediatric percentiles and adult thresholds. METHODS: BMI from 23 640 US teens ages 18-19 years were classified using paediatric BMI percentile criteria for underweight (< 5th), normal (5th to < 85th), overweight (85th to < 95th), obesity (≥ 95th) and severe obesity (≥ 120% × 95th percentile) and adult BMI (kg m(-2) ) criteria for underweight (< 18.5), normal (18.5-24.9), overweight (25-29.9) and obesity: class I (30-34.9), class II (35-39.9) and class III (≥ 40). Concordance was examined using the kappa (κ) statistic. Blood pressure (BP) from the same visit was classified hypertensive for BP ≥ 140/90. RESULTS: The majority of visits (72.8%) occurred in adult primary care. Using paediatric/adult criteria, 3.4%/5.2% were underweight, 66.6%/58.8% normal weight, 15.7%/21.7% overweight, 14.3%/14.3% obese and 4.9%/6.0% severely/class II-III obese, respectively. Paediatric and adult classification for underweight, normal, overweight and obesity were concordant for 90.3% (weighted κ 0.87 [95% confidence interval, 0.87-0.88]). For severe obesity, BMI ≥ 120% × 95th percentile showed high agreement with BMI ≥ 35 kg m(-2) (κ 0.89 [0.88-0.91]). Normal-weight males and moderately obese females by paediatric BMI percentile criteria who were discordantly classified into higher adult weight strata had a greater proportion with hypertensive BP compared with concordantly classified counterparts. CONCLUSIONS: Strong agreement exists between US paediatric BMI percentile and adult BMI classification for older teenagers. Adult BMI classification may optimize BMI tracking and risk stratification during transition from paediatric to adult care.


Subject(s)
Overweight/classification , Pediatrics/organization & administration , Primary Health Care/organization & administration , Thinness/classification , Transition to Adult Care , Adolescent , Adult , Blood Pressure , Body Mass Index , Child , Female , Humans , Hypertension , Male , United States , Young Adult
8.
Pediatr Obes ; 9(3): 167-75, 2014 Jun.
Article in English | MEDLINE | ID: mdl-23677690

ABSTRACT

BACKGROUND: Early childhood adiposity may have significant later health effects. This study examines the prevalence and recognition of obesity and severe obesity among preschool-aged children. METHODS: The electronic medical record was used to examine body mass index (BMI), height, sex and race/ethnicity in 42,559 children aged 3-5 years between 2007 and 2010. Normal or underweight (BMI < 85th percentile); overweight (BMI 85th-94th percentile); obesity (BMI ≥ 95th percentile); and severe obesity (BMI ≥ 1.2 × 95th percentile) were classified using the 2000 Centers for Disease Control and Prevention growth charts. Provider recognition of elevated BMI was examined for obese children aged 5 years. RESULTS: Among 42,559 children, 12.4% of boys and 10.0% of girls had BMI ≥ 95th percentile. The prevalence was highest among Hispanics (18.2% boys, 15.2% girls), followed by blacks (12.4% boys, 12.7% girls). A positive trend existed between increasing BMI category and median height percentile, with obesity rates highest in the highest height quintile. The prevalence of severe obesity was 1.6% overall and somewhat higher for boys compared with girls (1.9 vs. 1.4%, P < 0.01). By race/ethnicity, the highest prevalence of severe obesity was seen in Hispanic boys (3.3%). Among those aged 5 years, 77.9% of obese children had provider diagnosis of obesity or elevated BMI, increasing to 89.0% for the subset with severe obesity. CONCLUSIONS: Obesity and severe obesity are evident as early as age 3-5 years, with race/ethnic trends similar to older children. This study underscores the need for continued recognition and contextualization of early childhood obesity in order to develop effective strategies for early weight management.


Subject(s)
Black or African American/statistics & numerical data , Health Promotion , Hispanic or Latino/statistics & numerical data , Parenting , Pediatric Obesity/prevention & control , Body Mass Index , Child Nutritional Physiological Phenomena , Child, Preschool , Female , Health Education , Humans , Male , Parenting/ethnology , Pediatric Obesity/epidemiology , Pediatric Obesity/ethnology , Prevalence , Severity of Illness Index , Sex Factors , United States/epidemiology , White People/statistics & numerical data
9.
Bioinspir Biomim ; 8(4): 046006, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24166776

ABSTRACT

We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structural capacity (maximum leg force to avoid damage) and efficiency as the main goals for our control policies, since these objective functions are crucial to reduce motor size and structure weight. Each proposed policy controls the leg angle as a function of time during flight phase such that its objective function during the subsequent stance phase is regulated. The three objective functions that are regulated in the control policies are (i) the leg peak force, (ii) the axial impulse, and (iii) the leg actuator work. It should be noted that each control policy regulates one single objective function. Surprisingly, all three swing leg control policies result in nearly identical subsequent stance phase dynamics. This implies that the implementation of any of the proposed control policies would satisfy both goals (damage avoidance and efficiency) at once. Furthermore, all three control policies require a surprisingly simple leg angle adjustment: leg retraction with constant angular acceleration.


Subject(s)
Biomimetics/instrumentation , Biomimetics/methods , Birds/physiology , Extremities/physiology , Models, Biological , Motor Vehicles , Robotics/instrumentation , Running/physiology , Adaptation, Physiological/physiology , Animals , Computer Simulation , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Feedback , Feedback, Physiological/physiology
10.
J Intern Med ; 271(5): 510-20, 2012 May.
Article in English | MEDLINE | ID: mdl-22026504

ABSTRACT

OBJECTIVES: The aim of this study was to examine a large cohort of adults who received the zoster vaccine for evidence of an increased risk of prespecified adverse events requiring medical attention. DESIGN: Two self-comparison approaches, including a case-centred approach and a self-controlled case series (SCCS) analysis were used. SETTING: Eight managed-care organizations participating in the Vaccine Safety Datalink project in the United States. SUBJECTS: A total of 193 083 adults aged 50 and older receiving a zoster vaccine from 1 January 2007 to 31 December 2008 were included. MAIN OUTCOME MEASURES: Prespecified adverse events were identified by aggregated International Classification of Diseases, Ninth Revision (ICD-9) codes in automated health plan datasets. RESULTS: The risk of allergic reaction was significantly increased within 1-7 days of vaccination [relative risk = 2.13, 95% confidence interval (CI): 1.87-2.40 by case-centred method and relative rate = 2.32, 95% CI: 1.85-2.91 by SCCS]. No increased risk was found for the following adverse event groupings: cerebrovascular events; cardiovascular events; meningitis; encephalitis; and encephalopathy; and Ramsay-Hunt syndrome and Bell's palsy. CONCLUSIONS: The results of this study support the findings from the prelicensure clinical trials, providing reassurance that the zoster vaccine is generally safe and well-tolerated with a small increased risk of allergic reactions in 1-7 days after vaccination.


Subject(s)
Adverse Drug Reaction Reporting Systems/statistics & numerical data , Herpes Zoster Vaccine , Herpes Zoster/prevention & control , Aged , Aged, 80 and over , Cardiovascular Diseases/etiology , Cardiovascular Diseases/immunology , Cohort Studies , Female , Herpes Zoster/epidemiology , Herpes Zoster/immunology , Herpes Zoster Vaccine/administration & dosage , Herpes Zoster Vaccine/adverse effects , Humans , Hypersensitivity/etiology , Hypersensitivity/immunology , Male , Middle Aged , Nervous System Diseases/etiology , Nervous System Diseases/immunology , Population Surveillance , Risk Assessment , Time Factors , United States/epidemiology
11.
J Microsc ; 244(3): 273-92, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21974807

ABSTRACT

An algorithm for the automated segmentation of epithelial tissue in digital images of histologic tissue sections of odontogenic cysts (cysts originating from residual odontogenic epithelium) is presented. The algorithm features an image standardization process that greatly reduces variation in luminance and chrominance between images due to variations in sample preparation. Segmentation of the epithelial regions of images uses an algorithm based on binary graph cuts where graph weights depend on probabilities obtained from colour histogram models of epithelium and stroma image regions. Algorithm training used a data set of 38 images of four types of odontogenic cyst and was tested using a separate data set of 35 images of the same four cyst types. The best parameters for the segmentation algorithm were determined using a response-surface optimizer. The best parameter set resulted in an overall mean (± std. dev.) sensitivity of 91.5 ± 17% and overall mean specificity of 85.1 ± 18.6% on the training set. Particularly good results were obtained for dentigerous and odontogenic keratocysts for which the mean sensitivities/specificities were 91.9 ± 6.15%/97.4 ± 2.15% and 96.1 ± 1.98%/98.7 ± 3.16%, respectively. Our method is potentially applicable to many pathological conditions in similar tissues, such as skin and mucous membranes where there is a clear microscopic distinction between epithelium and connective tissues.


Subject(s)
Automation/methods , Epithelium/pathology , Histocytochemistry/methods , Image Processing, Computer-Assisted/methods , Odontogenic Cysts/pathology , Pathology/methods , Humans , Microscopy/methods , Radiography , Staining and Labeling/methods , Tooth/diagnostic imaging
12.
Anesthesiology ; 111(1): 203; author reply 203-4, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19546695
13.
Sleep Med ; 10(4): 427-38, 2009 Apr.
Article in English | MEDLINE | ID: mdl-18753000

ABSTRACT

BACKGROUND AND PURPOSE: To document and provide a micro analysis of the relationship between insomnia and health problems, health-care use, absenteeism, productivity and accidents. PARTICIPANTS AND METHODS: A population-based sample of 953 French-speaking adults from Québec, Canada. Participants were categorized as having insomnia syndrome (SYND) or insomnia symptoms (SYMPT) or as good sleepers (GS). They completed questionnaires on sleep, health, use of health-care services and products, accidents, work absences and reduced work productivity. Data were also obtained from the Québec-government-administered health insurance board on selected variables (e.g., consultations with health-care professionals, diagnoses). RESULTS: There were significantly more individuals in the SYND group relative to the GS group reporting at least one chronic health problem (83% vs. 53%; OR: 2.78) and who had consulted a health-care professional in the past year (81% vs. 60%; OR: 2.8). There were also higher proportions of individuals in the SYND group than in the GS group who had used prescription medications (57% vs. 30.7%; OR: 2.8), most notably to treat insomnia, mood and anxiety disorders, or who had used over-the-counter products (75.6% vs. 62.0%; OR: 1.8) and alcohol as a sleep aid (17.8% vs. 3.9%; OR: 4.6). In terms of daytime function, 25.0% of the SYND had been absent from work relative to 17.1% of GS (OR: 1.7), 40.6% reported having experienced reduced productivity compared to 12.3% of GS (OR: 4.8) and non-motor-vehicle accidents occurred at higher rates in the SYND group (12.5% vs. 6.4% for GS; OR: 2.4). No differences were found for hospitalisations or motor-vehicle accidents. Most of the associations remained significant even after controlling for psychiatric comorbidity. Rates for the SYMPT group were situated between SYND and GS on all major dependent variables. Furthermore, insomnia and fatigue were perceived as contributing significantly to accidents, absences and decreased work productivity, regardless of insomnia status. CONCLUSIONS: This study indicates that insomnia is associated with significant morbidity in terms of health problems and health-care utilization, work absenteeism and reduced productivity, and risk of non-motor-vehicle accidents. Future studies should evaluate whether treating insomnia can reverse this morbidity.


Subject(s)
Absenteeism , Accidents/statistics & numerical data , Cost of Illness , Health Services/statistics & numerical data , Sleep Initiation and Maintenance Disorders/complications , Sleep Initiation and Maintenance Disorders/psychology , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Efficiency , Female , Health Status , Health Surveys , Humans , Male , Middle Aged , Quebec , Self-Assessment , Sleep Initiation and Maintenance Disorders/therapy , Young Adult
14.
J Exp Biol ; 210(Pt 3): 383-94, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17234607

ABSTRACT

We currently know little about how animals achieve dynamic stability when running over uneven and unpredictable terrain, often characteristic of their natural environment. Here we investigate how limb and joint mechanics of an avian biped, the helmeted guinea fowl Numida meleagris, respond to an unexpected drop in terrain during running. In particular, we address how joint mechanics are coordinated to achieve whole limb dynamics. Based on muscle-tendon architecture and previous studies of steady and incline locomotion, we hypothesize a proximo-distal gradient in joint neuromechanical control. In this motor control strategy, (1) proximal muscles at the hip and knee joints are controlled primarily in a feedforward manner and exhibit load-insensitive mechanical performance, and (2) distal muscles at the ankle and tarsometatarso-phalangeal (TMP) joints are highly load-sensitive, due to intrinsic mechanical effects and rapid, higher gain proprioceptive feedback. Limb kinematics and kinetics during the unexpected perturbation reveal that limb retraction, controlled largely by the hip, remains similar to level running throughout the perturbed step, despite altered limb loading. Individual joints produce or absorb energy during both level and perturbed running steps, such that the net limb work depends on the balance of energy among the joints. The hip maintains the same mechanical role regardless of limb loading, whereas the ankle and TMP switch between spring-like or damping function depending on limb posture at ground contact. Initial knee angle sets limb posture and alters the balance of work among the joints, although the knee contributes little work itself. This distribution of joint function results in posture-dependent changes in work performance of the limb, which allow guinea fowl to rapidly produce or absorb energy in response to the perturbation. The results support the hypothesis that a proximo-distal gradient exists in limb neuromuscular performance and motor control. This control strategy allows limb cycling to remain constant, whereas limb posture, loading and energy performance are interdependent. We propose that this control strategy provides simple, rapid mechanisms for managing energy and controlling velocity when running over rough terrain.


Subject(s)
Galliformes/physiology , Joints/physiology , Running/physiology , Animals , Biomechanical Phenomena , Galliformes/anatomy & histology , Lower Extremity/physiology , Posture
15.
Neurology ; 67(1): 88-93, 2006 Jul 11.
Article in English | MEDLINE | ID: mdl-16832083

ABSTRACT

BACKGROUND: Many hospitals lack the infrastructure required to treat patients with acute stroke. The Brain Attack Coalition (BAC) published guidelines for the establishment of primary stroke centers. OBJECTIVE: To determine if stroke center designation and selective triage of acute stroke patients improve quality of care. METHODS: Baseline chart abstraction was performed on all stroke patients admitted to 32 hospitals serving Brooklyn and Queens, NY, from March to May 2002. Hospitals were invited to meet BAC guideline-based criteria. Adherence was verified by on-site visits. After designation, acute stroke patients were selectively triaged. Remeasurement data were collected from August to October 2003. RESULTS: The authors abstracted 1,598 charts at baseline and 1,442 charts at remeasurement. From baseline to remeasurement, median times decreased for door to physician contact (25 vs 15 minutes, p = 0.001), CT performance for potential tissue plasminogen activator (t-PA) candidates (68 vs 32 minutes, p < 0.001), and t-PA administration (109 vs 98 minutes (p = NS). IV t-PA utilization increased from 2.4 to 5.2% (p < 0.005), select t-PA protocol violations decreased from 11.1 to 7.9% (p = NS), and the stroke unit admission rate increased from 16 to 39% (p < 0.001). In stroke centers (n = 14) vs nondesignated hospitals (n = 18), there were shorter median times from door to physician contact (10 vs 25 minutes, p < 0.001), CT performance for potential t-PA candidates (31 vs 40 minutes, p = NS), and t-PA administration (95 vs 115 minutes, p < 0.05). Stroke centers, compared with nondesignated centers, admitted acute stroke patients to stroke units more often (55.9 vs 10.9%, p < 0.001). CONCLUSIONS: Stroke center designation and selective triage of acute stroke patients improved the quality of care, including access to timely thrombolytic therapy and stroke units.


Subject(s)
Guideline Adherence , Outcome Assessment, Health Care , Plasminogen Activators/therapeutic use , Public Health Administration , Quality of Health Care/statistics & numerical data , Stroke/therapy , Aged , Demography , Female , Hospital Departments , Humans , Male , New York/epidemiology , Retrospective Studies , Stroke/diagnosis , Stroke/epidemiology , Time Factors
16.
Acta Neurochir Suppl ; 96: 103-7, 2006.
Article in English | MEDLINE | ID: mdl-16671435

ABSTRACT

OBJECTIVES: To examine changes in cerebrovascular pressure transmission derived from arterial blood pressure (ABP) and intracranial pressure (ICP) recordings by autoregressive moving average modeling technique. METHODS: Digitized ICP and ABP recordings were obtained from patients with brain injury. Two groups were defined: Group A with 4 patients who demonstrated plateau waves, and Group B with 4 intracranial hypertensive, hypoperfused patients. For each 16.5 s interval, mean values of ICP, ABP, cerebral perfusion pressure (CPP), and corresponding highest modal frequency (HMF) of cerebrovascular pressure transmission were computed. RESULTS: Mean values of CPP and HMF of 56.2 mmHg and 2.0 Hz for Group A were significantly higher (p < 0.005) than corresponding mean values of 31.9 mmHg and 0.744 Hz for Group B. The mean value of the slope of the regression line between HMF and CPP for group A of -0.034 Hz/mmHg was significantly different (p < 0.025) than the mean value of 0.0077 Hz/mmHg for Group B. Computations of HMF, pressure reactivity, and correlation pressure reactivity index on continuous pressure recordings are illustrated. CONCLUSIONS: Values of HMF of cerebrovascular pressure transmission are inversely related to CPP when pressure regulation is thought to be intact, and directly related when regulation is likely lost.


Subject(s)
Blood Pressure , Brain Injuries/diagnosis , Diagnosis, Computer-Assisted/methods , Intracranial Hypertension/diagnosis , Intracranial Pressure , Manometry/methods , Models, Biological , Algorithms , Brain Injuries/physiopathology , Computer Simulation , Humans , Intracranial Hypertension/physiopathology , Reproducibility of Results , Sensitivity and Specificity
17.
Sleep Med ; 7(2): 123-30, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16459140

ABSTRACT

BACKGROUND AND PURPOSE: To estimate the prevalence of insomnia symptoms and syndrome in the general population, describe the types of self-help treatments and consultations initiated for insomnia, and examine help-seeking determinants. PATIENTS AND METHODS: A randomly selected sample of 2001 French-speaking adults from the province of Quebec (Canada) responded to a telephone survey about sleep, insomnia, and its treatments. RESULTS: Of the total sample, 25.3% were dissatisfied with their sleep, 29.9% reported insomnia symptoms, and 9.5% met criteria for an insomnia syndrome. Thirteen percent of the respondents had consulted a healthcare provider specifically for insomnia in their lifetime, with general practitioners being the most frequently consulted. Daytime fatigue (48%), psychological distress (40%), and physical discomfort (22%) were the main determinants prompting individuals with insomnia to seek treatment. Of the total sample, 15% had used at least once herbal/dietary products to facilitate sleep and 11% had used prescribed sleep medications in the year preceding the survey. Other self-help strategies employed to facilitate sleep included reading, listening to music, and relaxation. CONCLUSIONS: These findings confirm the high prevalence of insomnia in the general population. While few insomnia sufferers seek professional consultations, many individuals initiate self-help treatments, particularly when daytime impairments such as fatigue become more noticeable. Improved knowledge of the determinants of help-seeking behaviors could guide the development of effective public health prevention and intervention programs to promote healthy sleep.


Subject(s)
Patient Acceptance of Health Care , Referral and Consultation , Self-Help Groups , Sleep Initiation and Maintenance Disorders/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Demography , Female , Humans , Male , Middle Aged , Prevalence
18.
Cancer ; 104(4): 692-9, 2005 Aug 15.
Article in English | MEDLINE | ID: mdl-15981283

ABSTRACT

BACKGROUND: Severe anaphylactoid reactions to isosulfan blue dye requiring resuscitation are reported to occur in 1.1% of patients with breast carcinoma undergoing sentinel lymphadenectomy. In December 2001, the authors began administering a prophylactic regimen before dye injection to determine whether prophylaxis reduced the incidence of life-threatening reactions. METHODS: All patients were mapped with technetium-99m-labeled sulfur colloid. Those also receiving isosulfan blue dye were administered a glucocorticoid, diphenhydramine, and famotidine intravenously just before or at induction of anesthesia. Adverse reactions at the time of surgery were analyzed. RESULTS: Between December 2001 and July 2003, 1013 consecutive patients underwent sentinel lymphadenectomy for breast carcinoma. Six hundred sixty-seven patients (65.8%) received prophylaxis and isosulfan blue dye, 33 (3.3%) received prophylaxis but no dye, 12 (1.2%) received dye but no prophylaxis, and 301 (29.7%) received no prophylaxis or dye. Blue urticaria and facial edema were observed in 3 (0.5%) of 667 patients receiving prophylaxis and dye and in 1 (8.3%) of 12 patients receiving dye but no prophylaxis. There were no episodes of hypotension, and no patients required vasopressors, ventilatory support, or intensive care observation. Adverse reactions to agents other than blue dye were observed in 2 (0.3%) of 667 patients receiving prophylaxis and dye and in 3 (1.0%) of 301 receiving no prophylaxis and no dye (P = 0.1773). CONCLUSIONS: Preoperative prophylaxis was found to reduce the severity, but not the overall incidence, of adverse reactions to isosulfan blue dye. No life-threatening reactions were noted in patients treated with preoperative prophylaxis. Based on these results, the authors now routinely recommend administration of prophylaxis to patients receiving isosulfan blue for lymphatic mapping and sentinel lymph node biopsy.


Subject(s)
Anaphylaxis/epidemiology , Anaphylaxis/prevention & control , Breast Neoplasms/diagnosis , Glucocorticoids/therapeutic use , Histamine H1 Antagonists/therapeutic use , Rosaniline Dyes/adverse effects , Aged , Anaphylaxis/etiology , Clinical Protocols , Female , Humans , Incidence , Middle Aged , Preoperative Care , Prospective Studies , Sentinel Lymph Node Biopsy
19.
Acta Neurochir Suppl ; 95: 327-32, 2005.
Article in English | MEDLINE | ID: mdl-16463875

ABSTRACT

OBJECTIVE: To test the validity of the hypothesis that active vasodilatation and vasoconstriction underlie the occurrence of intracranial pressure (ICP) plateau waves by evaluating corresponding changes of cerebrovascular pressure transmission of arterial blood pressure (ABP) to ICP. METHODS: Digitized recordings of ICP and ABP sampled at 30 Hz were obtained from nine patients with traumatic brain injury. For each 16.5 s recording interval mean values of ICP, ABP, cerebral perfusion pressure (CPP), and the corresponding highest modal frequency (HMF) of cerebrovascular pressure transmission were calculated. RESULTS: Mean ICP and HMF significantly increased (P < 0.003) and mean CPP decreased significantly (P < 0.00036) at onset of the wave. Conversely at termination, mean ICP and HMF significantly decreased (P < 0.026) and mean CPP significantly increased (P < 0.028). In addition, the strong negative correlations between mean ICP and mean CPP (r = -0.87) and mean HMF and CPP (r = -0.87) were demonstrated. CONCLUSION: The findings that HMF increased at onset and decreased at the termination of plateau wave support the validity of the vasodilatatory/constriction cascade model that postulates active vasodilation at the onset and active vasoconstriction of the cerebrovascular bed at the termination of a plateau wave.


Subject(s)
Blood Pressure , Brain/blood supply , Brain/physiopathology , Cerebrovascular Circulation , Craniocerebral Trauma/physiopathology , Intracranial Pressure , Models, Biological , Computer Simulation , Humans , Manometry/methods , Pulsatile Flow , Vasoconstriction
20.
J Clin Anesth ; 16(5): 332-41, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15374553

ABSTRACT

STUDY OBJECTIVE: To describe the adverse events associated with the intraoperative injection of isosulfan blue in a large group of patients having a wide range of surgical procedures, and to identify risk factors for these events. DESIGN: Retrospective chart review. SETTING: University-affiliated institution specializing in malignancies PATIENTS: 1835 patients representing a total of 1852 surgical procedures. MEASUREMENTS: Incidence, type, severity, onset time, duration, management, and the presence of potential risk factors for adverse events. Events were considered "major" if potentially life-threatening hypotension occurred. MAIN RESULTS: Adverse events occurred in 28 procedures (1.5%) and 14 of these adverse events (0.75%) were classified as major. The types of events were: skin reactions in 21 patients, hypotension in 14 patients, edema in 1 patients, and unspecified in 1 patient. The time of onset for adverse events was 42.2 +/- 53.9 minutes (median, 17.5; range, 1 to 180 min) after isosulfan blue injection, and was significantly longer for minor reactions compared with major events (p = 0.015). The longest adverse event lasted at least 21 hours. Treatment was successful with usual antiallergy/antianaphylaxis medications. Ten patients received diphenhydramine alone, and four patients received intravenous epinephrine infusions. Factors associated with a significantly increased incidence of adverse events were isosulfan blue injection in the vulvar area (p = 0.000038), and the chronic preoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor-blocking agents (p = 0.043). Trends toward an increased risk of an adverse event were noted with isosulfan blue injection in the breast area (p = 0.19), and having more than one surgical procedure with isosulfan blue (p = 0.14). CONCLUSIONS: Although the most frequent adverse event associated with injection of isosulfan blue was a skin reaction, potentially life-threatening hypotension occurred in 0.75% of all procedures. Anesthesiologists must be aware of the variable onset time and potentially prolonged duration of the adverse events. They should recognize the need for extra vigilance in patients with potential risk factors, and have the usual antiallergy/antianaphylaxis medications available for administration if necessary.


Subject(s)
Rosaniline Dyes/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Injections , Intraoperative Period , Male , Middle Aged , Retrospective Studies , Risk Factors , Time Factors
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