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1.
Pediatr Blood Cancer ; 71(7): e31048, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38693643

ABSTRACT

BACKGROUND AND OBJECTIVE: National guidelines recommend that children with sickle cell anemia (SCA) be seen regularly by primary care providers (PCPs) as well as hematologists to receive comprehensive, multidisciplinary care. The objective is to characterize the patterns of primary and hematology care for children with SCA in Michigan. METHODS: Using validated claims definitions, children ages 1-17 years with SCA were identified using Michigan Medicaid administrative claims from 2010 to 2018. We calculated the number of outpatient PCP and hematologist visits per person-year, as well as the proportion of children with at least one visit to a PCP, hematologist, or both a PCP and hematologist annually. Negative binomial regression was used to calculate annual rates of visits for each provider type. RESULTS: A total of 875 children contributed 2889 person-years. Of the total 22,570 outpatient visits, 52% were with a PCP and 34% with a hematologist. Annually, 87%-93% of children had a visit with a PCP, and 63%-85% had a visit with a hematologist. Approximately 66% of total person-years had both visit types within a year. The annual rate ranged from 2.3 to 2.5 for hematologist visits and from 3.7 to 4.1 for PCP visits. CONCLUSIONS: Substantial gaps exist in the receipt of annual hematology care. Given that the majority of children with SCA see a PCP annually, strategies to leverage primary care visits experienced by this population may be needed to increase receipt of SCA-specific services.


Subject(s)
Anemia, Sickle Cell , Primary Health Care , Humans , Anemia, Sickle Cell/therapy , Child , Male , Child, Preschool , Female , Adolescent , Infant , Primary Health Care/statistics & numerical data , United States , Michigan , Hematology , Follow-Up Studies , Medicaid/statistics & numerical data , Prognosis
3.
Am J Obstet Gynecol ; 229(3): 320.e1-320.e7, 2023 09.
Article in English | MEDLINE | ID: mdl-37244455

ABSTRACT

BACKGROUND: There are no definitive guidelines for surgical treatment of pelvic organ prolapse. Previous data suggests geographic variation in apical repair rates in health systems throughout the United States. Such variation can reflect lack of standardized treatment pathways. An additional area of variation for pelvic organ prolapse repair may be hysterectomy approach which could not only influence concurrent repair procedures, but also healthcare utilization. OBJECTIVE: This study aimed to examine statewide geographic variation in surgical approach of hysterectomy for prolapse repair and concurrent use of colporrhaphy and colpopexy. STUDY DESIGN: We conducted a retrospective analysis of Blue Cross Blue Shield, Medicare, and Medicaid fee-for-service insurance claims for hysterectomies performed for prolapse in Michigan between October 2015 and December 2021. Prolapse was identified with International Classification of Disease Tenth Revision codes. The primary outcome was variation in surgical approach for hysterectomy as determined by Current Procedural Terminology code (vaginal, laparoscopic, laparoscopic assisted vaginal, or abdominal) on a county level. Patient home address zip codes were used to determine county of residence. A hierarchical multivariable logistic regression model with vaginal approach as the dependent variable and county-level random effects was estimated. Patient attributes, including age, comorbidities (diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, morbid obesity), concurrent gynecologic diagnoses, health insurance type, and social vulnerability index were used as fixed-effects. To estimate variation between counties in vaginal hysterectomy rates, a median odds ratio was calculated. RESULTS: There were 6974 hysterectomies for prolapse representing 78 total counties that met eligibility criteria. Of these, 2865 (41.1%) underwent vaginal hysterectomy, 1119 (16.0%) underwent laparoscopic assisted vaginal hysterectomy, and 2990 (42.9%) underwent laparoscopic hysterectomy. The proportion of vaginal hysterectomy across 78 counties ranged from 5.8% to 86.8%. The median odds ratio was 1.86 (95% credible interval, 1.33-3.83), consistent with a high level of variation. Thirty-seven counties were considered statistical outliers because the observed proportion of vaginal hysterectomy was outside the predicted range (as defined by confidence intervals of the funnel plot). Vaginal hysterectomy was associated with higher rates of concurrent colporrhaphy than laparoscopic assisted vaginal hysterectomy or laparoscopic hysterectomy (88.5% vs 65.6% vs 41.1%, respectively; P<.001) and lower rates of concurrent colpopexy (45.7% vs 51.7% vs 80.1%, respectively; P<.001). CONCLUSION: This statewide analysis reveals a significant level of variation in the surgical approach for hysterectomies performed for prolapse. The variation in surgical approach for hysterectomy may help account for high rates of variation in concurrent procedures, especially apical suspension procedures. These data highlight how geographic location may influence the surgical procedures a patient undergoes for uterine prolapse.


Subject(s)
Medicare , Pelvic Organ Prolapse , Aged , Female , United States/epidemiology , Humans , Retrospective Studies , Hysterectomy/methods , Hysterectomy, Vaginal/methods , Pelvic Organ Prolapse/epidemiology , Pelvic Organ Prolapse/surgery , Gynecologic Surgical Procedures/methods
4.
Pediatr Blood Cancer ; 70(7): e30332, 2023 07.
Article in English | MEDLINE | ID: mdl-37046404

ABSTRACT

OBJECTIVE: Hydroxyurea lowers the incidence of vaso-occlusive pain crises (VOC) and acute chest syndrome (ACS) among children with sickle cell anemia (SCA). Our objective was to assess the relationship between levels of adherence to hydroxyurea and clinical outcomes among children and adolescents with SCA. METHODS: This retrospective cohort study included Medicaid data (2005-2012) from Florida, Illinois, Louisiana, Michigan, South Carolina, and Texas. The study population consisted of children 1-17 years old with SCA enrolled in Medicaid for 3 years. Among children that initiated hydroxyurea, the medication possession ratio (MPR) was calculated as the proportion of days covered by hydroxyurea. Six months after initiation of hydroxyurea, clinical outcomes were assessed through the end of the study period: numbers of VOC-related inpatient admissions and emergency department visits, and encounters for ACS. Multivariable Poisson models were used to predict outcomes by MPR quartile adjusting for previous healthcare utilization, state, and age. RESULTS: Hydroxyurea was initiated by 515 children. The median MPR was 0.53 (interquartile range = 0.3-0.8). The annual median number of visits was 0.0 for ACS, 1.3 for VOC-related emergency department, and 1.4 for VOC-related inpatient admissions. For each outcome, the highest quartile of MPR had the lowest predicted count; this difference was significant for ACS visits when compared with the lowest quartile of MPR. CONCLUSION: This study demonstrated a high level of adherence (>75%) was essential to achieve a lower incidence of common negative clinical outcomes. Further, moderate and severe hydroxyurea nonadherence may be more common than previously appreciated among children, emphasizing the importance of developing and testing innovative strategies to increase adherence.


Subject(s)
Acute Chest Syndrome , Anemia, Sickle Cell , Volatile Organic Compounds , Adolescent , Humans , Child , Infant , Child, Preschool , Hydroxyurea/therapeutic use , Retrospective Studies , Volatile Organic Compounds/therapeutic use , Anemia, Sickle Cell/drug therapy , Acute Chest Syndrome/drug therapy , Antisickling Agents/therapeutic use
5.
Acad Pediatr ; 22(3S): S119-S124, 2022 04.
Article in English | MEDLINE | ID: mdl-35339238

ABSTRACT

BACKGROUND: Measuring quality at varying levels of the health care system requires attribution, a process of determining the patients and services for which each level is responsible. However, it is important to ensure that attribution approaches are equitable; otherwise, individuals may be assigned differentially based upon social determinants of health. METHODS: First, we used Medicaid claims (2010-2018) from Michigan to assess the proportion of children with sickle cell anemia who had less than 12 months enrollment within a single Medicaid health plan and could therefore not be attributed to a specific health plan. Second, we used the Medicaid Analytic eXtract data (2008-2009) from 26 states to simulate adapting the 30-Day Pediatric All-Condition Readmission measure to the Accountable Care Organization (ACO) level and examined the proportion of readmissions that could not be attributed. RESULTS: For the sickle cell measure, an average of 300 children with sickle cell anemia were enrolled in Michigan Medicaid each year. The proportion of children that could not be attributed to a Medicaid health plan ranged from 12.2% to 89.0% across years. For the readmissions measure, of the 1,051,365 index admissions, 22% were excluded in the ACO-level analysis because of being unable to attribute the patient to a health plan for the 30 days post discharge. CONCLUSIONS: When applying attribution models, it is essential to consider the potential to induce health disparities. Differential attribution may have unintentional consequences that deepen health disparities, particularly when considering incentive programs for health plans to improve the quality of care.


Subject(s)
Accountable Care Organizations , Anemia, Sickle Cell , Aftercare , Anemia, Sickle Cell/therapy , Child , Data Aggregation , Humans , Medicaid , Patient Discharge , United States
6.
Telemed J E Health ; 28(8): 1166-1171, 2022 08.
Article in English | MEDLINE | ID: mdl-34986030

ABSTRACT

Introduction: Sickle cell anemia (SCA) is a genetic condition that predominantly affects minority populations in the United States. A lack of access to care is strongly associated with poor outcomes and quality of care among children and adolescents with SCA. The use of telehealth, which has rapidly expanded during the COVID-19 pandemic, has been shown to improve access to care for many conditions. However, the adoption of telehealth among children and adolescents with SCA is unknown. Methods: We identified children 1-17 years old with SCA continuously enrolled in Michigan Medicaid from January 2019 to December 2020. The number of in-person and telehealth outpatient visits (both urgent and routine) were summarized prepandemic (January 2019-February 2020) and during the pandemic (March 2020-December 2020); National Provider Identifier was used to identify provider specialty for telehealth visits. Results: The study population comprised 493 children with SCA with a mean age of 8.7 (±4.9) years at study entry. Prepandemic, there were 4,367 outpatient visits; 4,348 (99.6%) were in-person and 19 (0.4%) were telehealth. During the pandemic, there were 2,307 outpatient visits; 2,059 (89.3%) were in-person and 248 (10.7%) were telehealth. Telehealth visits peaked in April 2020 and declined thereafter. The majority of telehealth visits were to hematology (49%), followed by adult subspecialists (27%) and pediatrics/family medicine (14%). Discussion/Conclusions: While the overall number of outpatient visits declined during the initial months of the pandemic compared with 2019, use of telehealth rapidly increased among children and adolescents with SCA. Additional research is needed to understand patient and provider preferences for telehealth and the roles that federal and state policies can play in facilitating telehealth adoption among children and adolescents with SCA.


Subject(s)
Anemia, Sickle Cell , COVID-19 , Telemedicine , Adolescent , Adult , Anemia, Sickle Cell/epidemiology , Anemia, Sickle Cell/therapy , COVID-19/epidemiology , Child , Child, Preschool , Humans , Infant , Medicaid , Pandemics , United States/epidemiology
7.
Pediatr Blood Cancer ; 69(2): e29446, 2022 02.
Article in English | MEDLINE | ID: mdl-34854548

ABSTRACT

INTRODUCTION: For decades, it has been recommended that children with sickle cell anemia (SCA) receive antibiotic prophylaxis to prevent serious infections and undergo transcranial Doppler (TCD) screening to identify those at highest risk of overt stroke. We assessed recent temporal trends in antibiotic prophylaxis prescription fills and TCD screening among children with SCA using validated quality measures. PROCEDURE: Using validated claims-based definitions, we identified children with SCA who were enrolled in Michigan or New York State (NYS) Medicaid programs (2011-2018). Among recommended age groups, two outcomes were assessed yearly: (a) filling of ≥300 days of antibiotics, and (b) receipt of greater than or equal to one TCD. The proportion of children with each outcome was calculated by state. Temporal trends in each preventive service were assessed using generalized linear models. RESULTS: A total of 1784 children were eligible for antibiotic prophylaxis (Michigan: 384; NYS: 1400), contributing 3322 person-years. Annual rates of filling ≥300 days of antibiotics ranged from 16% to 22% and were similar by state. There was no change in rates of antibiotic filling over time in Michigan (p-value: .10), but there was a decrease in NYS (p-value: .02). A total of 3439 children with SCA were eligible for TCD screening (Michigan: 710; NYS: 2729), contributing 10,012 person-years. Annual rates of TCD screening ranged from 39% to 45%, were similar by state, and did not change over time (p-values >.05). CONCLUSIONS: Most children with SCA do not receive recommended antibiotic prophylaxis and/or TCD screening. New, sustainable, and coordinated interventions across preventive services are urgently needed.


Subject(s)
Anemia, Sickle Cell , Stroke , Anemia, Sickle Cell/diagnosis , Anemia, Sickle Cell/therapy , Anti-Bacterial Agents/therapeutic use , Child , Humans , Mass Screening , Stroke/prevention & control , Ultrasonography, Doppler, Transcranial
8.
iScience ; 24(6): 102489, 2021 Jun 25.
Article in English | MEDLINE | ID: mdl-33969281

ABSTRACT

The SARS-CoV-2 viral pandemic has induced a global health crisis, which requires more in-depth investigation into immunological responses to develop effective treatments and vaccines. To understand protective immunity against COVID-19, we screened over 60,000 asymptomatic individuals in the Southeastern United States for IgG antibody positivity against the viral Spike protein, and approximately 3% were positive. Of these 3%, individuals with the highest anti-S or anti-RBD IgG level showed a strong correlation with inhibition of ACE2 binding and cross-reactivity against non-SARS-CoV-2 coronavirus S-proteins. We also analyzed samples from 94 SARS-CoV-2 patients and compared them with those of asymptomatic individuals. SARS-CoV-2 symptomatic patients had decreased antibody responses, ACE2 binding inhibition, and antibody cross-reactivity. Our study shows that healthy individuals can mount robust immune responses against SARS-CoV-2 without symptoms. Furthermore, IgG antibody responses against S and RBD may correlate with high inhibition of ACE2 binding in individuals tested for SARS-CoV-2 infection or post vaccination.

9.
Health Serv Res ; 55(2): 310-317, 2020 04.
Article in English | MEDLINE | ID: mdl-31916247

ABSTRACT

OBJECTIVE: To develop, test, and validate the performance of ICD-10-CM claims-based case definitions for identifying children with sickle cell anemia (SCA). DATA SOURCES: Medicaid administrative claims (2016) for children <18 years with potential SCA (any D57x diagnosis code) and newborn screening records from Michigan and New York State. STUDY DESIGN: This study is a secondary data analysis. DATA COLLECTION/EXTRACTION METHODS: Using specific SCA-related (D5700, D5701, and D5702) and nonspecific (D571) diagnosis codes, 23 SCA case definitions were applied to Michigan Medicaid claims (2016) to identify children with SCA. Measures of performance (sensitivity, specificity, area under the ROC curve) were calculated using newborn screening results as the gold standard. A parallel analysis was conducted using New York State Medicaid claims and newborn screening data. PRINCIPAL FINDINGS: In Michigan Medicaid, 1597 children had ≥1 D57x claim; 280 (18 percent) were diagnosed with SCA. Measures of performance varied, with sensitivities from 0.02 to 0.97 and specificities from 0.88 to 1.0. The case definition of ≥1 outpatient visit with a SCA-related or D571 code had the highest area under the ROC curve, with a sensitivity of 95 percent and specificity of 92 percent. The same definition also had the highest performance in New York Medicaid (n = 2454), with a sensitivity of 94 percent and specificity of 86 percent. CONCLUSIONS: Children with SCA can be accurately identified in administrative claims using this straightforward case definition. This methodology can be used to monitor trends and use of health services after transition to ICD-10-CM.


Subject(s)
Anemia, Sickle Cell/classification , Anemia, Sickle Cell/diagnosis , Guidelines as Topic , International Classification of Diseases/standards , Medicaid/standards , Adolescent , Anemia, Sickle Cell/epidemiology , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Michigan/epidemiology , New York/epidemiology , Reproducibility of Results , Socioeconomic Factors , United States
10.
J Palliat Med ; 22(8): 1009-1013, 2019 08.
Article in English | MEDLINE | ID: mdl-30864873

ABSTRACT

Introduction: Terminal bleeding, a distressing symptom experience for patients, caregivers, and health professionals, occurs in a subset of patients in the palliative care setting. Terminal bleeding is often thought of as a large-volume catastrophically fatal event, but it can also occur for a longer period of time and still be the precipitating event for a patient's death. Case Report: We present the case of terminal bleeding in an 87-year-old patient with angiosarcoma, a rare aggressive vascular neoplasm that can occur anywhere in the body but tend to occur more frequently in the head and neck. Discussion: The patient's advanced age and aggressive disease presented challenges in managing the symptoms and precluded many of the conventional recommended interventions to manage bleeding. Conclusion: This case report speaks to the need for multidisciplinary planning that takes prognosis, performance status, previous therapies, and patient preferences into account when caring for patients with advanced cancer.


Subject(s)
Hemangiosarcoma/complications , Hemangiosarcoma/nursing , Hemorrhage/etiology , Hemorrhage/nursing , Palliative Care/methods , Aged, 80 and over , Fatal Outcome , Female , Humans
11.
Pediatrics ; 141(3)2018 03.
Article in English | MEDLINE | ID: mdl-29437860

ABSTRACT

BACKGROUND: Children with sickle cell anemia (SCA) are at increased risk for invasive pneumococcal disease; antibiotic prophylaxis significantly reduces this risk. We calculated the proportion of children with SCA who received ≥300 days of antibiotic prophylaxis and identified predictors of such receipt. METHODS: Children aged 3 months to 5 years with SCA were identified by the presence of 3 or more Medicaid claims with a diagnosis of SCA within a calendar year (2005-2012) in Florida, Illinois, Louisiana, Michigan, South Carolina, and Texas. Receipt of antibiotics was identified through claims for filled prescriptions. The outcome, receipt of ≥300 days of antibiotics, was assessed annually by using varying classifications of antibiotics. By using logistic regression with generalized estimating equations, we estimated the odds of receiving ≥300 days of antibiotics, with potential predictors of age, sex, year, state, and health services use. RESULTS: A total of 2821 children contributed 5014 person-years. Overall, only 18% of children received ≥300 days of antibiotics. Each additional sickle cell disease-related outpatient visit (odds ratio = 1.01, 95% confidence interval: 1.01-1.02) and well-child visit (odds ratio = 1.08, 95% confidence interval: 1.02-1.13) was associated with incrementally increased odds of receiving ≥300 days of antibiotics. CONCLUSIONS: Despite national recommendations and proven lifesaving benefit, antibiotic prophylaxis rates are low among children with SCA. Numerous health care encounters may offer an opportunity for intervention; in addition, such interventions likely need to include social factors that may affect the ability for a child to receive and adhere to antibiotic prophylaxis.


Subject(s)
Anemia, Sickle Cell/microbiology , Antibiotic Prophylaxis/statistics & numerical data , Pneumococcal Infections/prevention & control , Child, Preschool , Drug Utilization , Female , Guideline Adherence , Humans , Infant , Male , Medication Adherence , Practice Guidelines as Topic , Risk Factors , United States
12.
Pediatrics ; 140(2)2017 08.
Article in English | MEDLINE | ID: mdl-28739652

ABSTRACT

BACKGROUND AND OBJECTIVES: Sepsis syndrome, comprising sepsis, severe sepsis, and septic shock, is a leading cause of child mortality and morbidity, for which the delivery of time-sensitive care leads to improved survival. We aimed to describe the development and testing of quality measures for in-hospital care of pediatric sepsis syndrome. METHODS: Seven measures of quality of care for children hospitalized with sepsis syndrome were developed by using an iterative process including literature review, development of concepts and candidate measures, and selection of measures for feasibility and importance by 2 panels of experts. The measures were tested for reliability and validity among children 0 to 18 years of age hospitalized with sepsis syndrome from January 1, 2012, to June 30, 2013. RESULTS: Of 27 hospitals, 59% had no protocol for the identification and treatment of pediatric sepsis syndrome. Blood culture was performed in only 70% of patients with pediatric sepsis syndrome. Antibiotics were administered within 1 hour of diagnosis in 70% of patients with pediatric severe sepsis or septic shock, and timely fluid resuscitation was performed in 50% of patients with severe sepsis or septic shock. Documentation of heart rate during fluid resuscitation of children with severe sepsis or septic shock was observed in 18% of cases. Two measures could not be rigorously tested for validity and reliability given the rarity of septic shock and were deemed infeasible. CONCLUSIONS: This multisite study to develop and validate measures of the quality of hospital care of children with sepsis syndrome highlights the existence of important gaps in delivery of care.


Subject(s)
Emergency Service, Hospital/standards , Quality Assurance, Health Care , Sepsis/diagnosis , Sepsis/drug therapy , Anti-Bacterial Agents/therapeutic use , Blood Culture , Child , Clinical Protocols , Emergency Service, Hospital/organization & administration , Fluid Therapy , Heart Rate , Hospitalization , Humans , Monitoring, Physiologic , Sepsis/physiopathology
13.
JAMA Pediatr ; 170(6): 550-6, 2016 06 01.
Article in English | MEDLINE | ID: mdl-27064406

ABSTRACT

IMPORTANCE: With transcranial Doppler (TCD) screening, we can identify children and adolescents with sickle cell anemia who are at the highest risk of stroke. An accurate claims-based method for identifying children and adolescents with sickle cell anemia was recently developed and validated that establishes the necessary groundwork to enable large population-based assessments of health services utilization among children and adolescents with sickle cell anemia using administrative claims data. OBJECTIVE: To assess the feasibility of using administrative claims data to identify and describe the receipt of TCD screening among children and adolescents with sickle cell anemia and to characterize opportunities for intervention. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cross-sectional study using Medicaid claims data from 2005 to 2010. Medicaid claims data were obtained from the following states: Florida, Illinois, Louisiana, Michigan, South Carolina, and Texas. Children and adolescents 2 to 16 years of age with sickle cell anemia were identified by the presence of 3 or more Medicaid claims with a diagnosis of sickle cell anemia within a calendar year (2005-2010). A total of 4775 children and adolescents contributed 10 787 person-years throughout the study period. Data were analyzed in 2015. A subset of children and adolescents enrolled for 2 or more consecutive years was identified to examine potential predictors of TCD screening, which included age, sex, previous receipt of TCD screening, state of residence, and health services utilization (well-child visits, outpatient visits, emergency department visits, and inpatient visits). MAIN OUTCOMES AND MEASURES: Receipt of TCD screening was assessed by year and state. Using logistic regression with generalized estimating equations, we included associated predictors in a multivariable model to estimate odds of TCD screening. RESULTS: For a total of 4775 children and adolescents 2 to 16 years of age, TCD screening rates increased over the 6-year study period from 22% to 44% (P < .001); rates varied substantially across states. A subset of 2388 children and adolescents with sickle cell anemia (50%) was enrolled for 2 or more consecutive years. Each year of increasing age was associated with 3% lower odds of TCD screening (odds ratio, 0.97 [95% CI, 0.95-0.98]; P = .002). Previous receipt of TCD screening (odds ratio, 2.44 [95% CI, 2.11-2.81]; P < .001) and well-child visits (odds ratio, 1.10 [95% CI, 1.03-1.18]; P = .007) were associated with higher odds of receiving a TCD screening. CONCLUSIONS AND RELEVANCE: Despite national recommendations, TCD screening rates remain low. Successful strategies to improve TCD screening rates may capitalize on the numerous health care interactions among children and adolescents with sickle cell anemia.


Subject(s)
Anemia, Sickle Cell/diagnostic imaging , Adolescent , Child , Child, Preschool , Cross-Sectional Studies , Early Diagnosis , Feasibility Studies , Female , Humans , Male , Medicaid/statistics & numerical data , Retrospective Studies , Stroke/diagnostic imaging , Stroke/prevention & control , Ultrasonography, Doppler, Transcranial , United States
14.
Article in English | MEDLINE | ID: mdl-19964631

ABSTRACT

This paper presents a detailed study of the vibrations on the surface of the neck during a vocalization of predefined fundamental frequency and intensity. This study was carried out as part of a wider investigation into the use of laryngeal vibrations as a channel of communication. Another potential application of this study is in identifying a suitable location for a hands-free electro-larynx for laryngectomees. An analog accelerometer, with dimensions 5x5x1.6mm and of mass 80mg, was used to perform the measurements. It was connected to a 12-bit analog to digital converter via single strands of insulated wire with a diameter of 100 microm. The resulting low inertia of the measuring device minimised the effect of the measuring device on the phenomenon under investigation. The analog to digital converter simultaneously sampled the accelerometer output and a pre-amplified audio signal from a microphone. This preliminary study was carried out on two able-bodied male subjects. Measurements were taken from forty-five preselected locations on the neck. Each subject made the vowel sound /i/ (long 'e') at three different fundamental frequencies, 150Hz, 200Hz and 250Hz. Once the vocal pitch and intensity matched pre-defined target values, a 200 ms recording was captured by a virtual instrument designed in LabVIEW. A detailed map of skin surface vibration amplitude during vocalization is presented and suitable locations for laryngeal vibration measurement are identified. Further more, detailed analysis of the time varying acceleration function at various measurement positions reveals a rich and complex source of information. Novel visualizations of these signals are presented.


Subject(s)
Electronics, Medical/instrumentation , Neck/anatomy & histology , Speech/physiology , Vibration , Acceleration , Humans , Male
15.
J Rehabil Res Dev ; 46(4): 499-514, 2009.
Article in English | MEDLINE | ID: mdl-19882485

ABSTRACT

Many wheelchair users remain in their wheelchairs during transit. Safety research for wheelchair users has focused mainly on frontal impact. However, although they are generally less severe, rear-impact injuries are expensive and difficult to treat and whiplash injury protection for adult wheelchair users remains poorly understood. In this article, 10 g (16 km/h) rear-impact sled tests conducted with the Biofidelic Rear Impact Dummy II or BioRID-II (Denton ATD Inc and Chalmers University of Technology; Gothenburg, Sweden) seated in a rigid wheelchair with no head restraint showed that Abbreviated Injury Scale-score 1 neck injury risk evaluated with the neck injury criterion (NIC) and Nkm criterion is substantially above proposed threshold levels. A prototype wheelchair head restraint was developed and tested together with an existing commercial head restraint (Rolko; Borgholzhausen, Germany) in the same 10 g (16 km/h) rear impact. Both head restraints reduced the injury scores substantially. NIC test scores for the head restraints with no gap ranged from 18 to 24 (approximately 20%-30% chance of neck injury symptoms of duration >1 month) compared with test scores for no head restraints that ranged from 34 to 37 (approximately 95% chance of neck injury). The corresponding extension-posterior Nkm scores with no gap ranged from 0.30 to 0.35 (approximately 5% chance of neck injury) compared with no head restraint of 1.16 (approximately 45% chance of neck injury symptoms). However, the number of sled tests performed was small (three with no head restraint and six with a head restraint), and these results should be considered mainly trends. Preliminary results also showed that the horizontal gap between the head and the wheelchair head-restraint cushion should be as small possible.


Subject(s)
Protective Devices , Wheelchairs , Whiplash Injuries/etiology , Whiplash Injuries/prevention & control , Adult , Equipment Design , Head Movements , Humans , Manikins , Range of Motion, Articular , Restraint, Physical , Risk Factors , Weight-Bearing , Whiplash Injuries/physiopathology
18.
J Cell Sci ; 115(Pt 7): 1441-51, 2002 Apr 01.
Article in English | MEDLINE | ID: mdl-11896192

ABSTRACT

Melanosomes are specialized melanin-synthesizing organelles critical for photoprotection in the skin. Melanosome transfer to keratinocytes, which involves whole organelle donation to another cell, is a unique biological process and is poorly understood. Time-lapse digital movies and electron microscopy show that filopodia from melanocyte dendrites serve as conduits for melanosome transfer to keratinocytes. Cdc42, a small GTP-binding protein, is known to mediate filopodia formation. Melanosome-enriched fractions isolated from human melanocytes expressed the Cdc42 effector proteins PAK1 and N-WASP by western blotting. Expression of constitutively active Cdc42 (Cdc42(V12)) in melanocytes co-cultured with keratinocytes induced a highly dendritic phenotype with extensive contacts between melanocytes and keratinocytes through filopodia, many of which contained melanosomes. These results suggest a unique role for filopodia in organelle transport and, in combination with our previous work showing the presence of SNARE proteins and rab3a on melanosomes, suggest a novel model system for melanosome transfer to keratinocytes.


Subject(s)
Keratinocytes/metabolism , Melanosomes/metabolism , Pseudopodia/physiology , Biological Transport , Cells, Cultured , Humans , Image Processing, Computer-Assisted , Keratinocytes/ultrastructure , Melanosomes/ultrastructure , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/metabolism , Protein Kinases/biosynthesis , Protein Kinases/metabolism , Pseudopodia/ultrastructure , Wiskott-Aldrich Syndrome Protein, Neuronal , cdc42 GTP-Binding Protein/metabolism
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