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1.
Appl Nurs Res ; 69: 151665, 2023 02.
Article in English | MEDLINE | ID: mdl-36635006

ABSTRACT

BACKGROUND: Healthy diet, exercise, and sleep practices may mitigate stress and prevent illness. However, lifestyle behaviors of acute care nurses working during stressful COVID-19 surges are unclear. PURPOSE: To quantify sleep, diet, and exercise practices of 12-hour acute care nurses working day or night shift during COVID-19-related surges. METHODS: Nurses across 10 hospitals in the United States wore wrist actigraphs and pedometers to quantify sleep and steps and completed electronic diaries documenting diet over 7-days. FINDINGS: Participant average sleep quantity did not meet national recommendations; night shift nurses (n = 23) slept significantly less before on-duty days when compared to day shift nurses (n = 34). Proportionally more night shift nurses did not meet daily step recommendations. Diet quality was low on average among participants. DISCUSSION: Nurses, especially those on night shift, may require resources to support healthy sleep hygiene, physical activity practices, and diet quality to mitigate stressful work environments.


Subject(s)
COVID-19 , Nurses , Sleep Disorders, Circadian Rhythm , Humans , Work Schedule Tolerance , Sleep , Diet , Exercise
2.
Radiat Prot Dosimetry ; 153(2): 251-4, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23175645

ABSTRACT

As digital technology in diagnostic radiology systems becomes more prevalent, there is a need to provide comparative dose information for these new systems. This is needed in particular for testing the automatic exposure control (AEC) devices on direct digital radiography (DDR) systems as there is no consensus on the receptor dose level in the current guidelines. The new European Commission RP 162 document sets the suspension level for the 'verification of kerma at receptor entrance in computed radiography and DDR systems under AEC' as ≥10 µGy. This document also notes that alternate methodologies are acceptable, and may require adjustment in the suspension level if used. This study provides a range of typical doses under AEC for DDR systems, for a variety measurement methodologies, including that described in RP 162.


Subject(s)
Radiographic Image Enhancement/instrumentation , Radiographic Image Enhancement/standards , Radiology/instrumentation , Radiology/standards , Equipment Design , Humans , Phantoms, Imaging , Radiation Dosage , Radiographic Image Enhancement/methods , Radiology/methods , Radiometry/methods , Reproducibility of Results , Water/chemistry , X-Rays
3.
Int J Immunopathol Pharmacol ; 25(4): 1121-30, 2012.
Article in English | MEDLINE | ID: mdl-23298502

ABSTRACT

This study sought to determine the appropriate starting dose of colchicine in children aged 2 to 4 years with familial Mediterranean fever (FMF) based on steady-state pharmacokinetics in pediatric patients with FMF from 2 to less than 16 years and adult patients with FMF from 16 to 65 years. Outpatients received colchicine for 90 days starting with a fixed dose for 14 days (blood sampling days 14 and 15). After starting doses of colchicine (0.6 mg/day [2 to less than 4 years], 0.9 mg/day [from 4 to less than 6 years], 0.9 mg/day [from 6 to less than 12 years], 1.2 mg/day [from 12 to less than 16 years], and 1.2 mg/day [from 16 to less than 65 years]), the observed steady-state pharmacokinetic parameters were comparable across age groups, despite the higher doses of colchicine on a mg/kg/day basis in the younger age groups. An exception occurred with once-daily colchicine, whereby mean Cmax for colchicine was higher in patients 4 to less than 6 years (9.4 ng/mL) compared with the younger and older age groups (6.1-6.7 ng/mL). Mean AUC0?24h values in children 2 to less than 4, 6 to less than 12, and 12 to less than 16 years were similar to those in adults. However, mean AUC0?24h values in children 4 to less than 6 years were 25 percent higher than those observed in adults. The results show that the recommended starting dose for children 2-4 years and 4-6 years should be 0.6 mg/day (half the US adult dose). Children aged 6 to less than 12 years should receive 0.9 mg/day (i.e. three-quarters of the US adult dose). The safety of colchicine in children 2 to less than 4 years was comparable to that in older children and adults.


Subject(s)
Colchicine/pharmacokinetics , Familial Mediterranean Fever/drug therapy , Adolescent , Adult , Aged , Child , Child, Preschool , Colchicine/administration & dosage , Colchicine/adverse effects , Female , Humans , Male , Middle Aged
4.
Physiother Can ; 63(4): 41-420, 2011.
Article in English | MEDLINE | ID: mdl-22942514

ABSTRACT

PURPOSE: Older adults with decreased confidence in their ability to prevent a fall may benefit from an exercise programme that includes self-efficacy-enhancing education. The objectives of this study were to explore differences in fall-risk outcomes in older adults with higher vs. lower levels of falls efficacy and to evaluate the relationship between baseline falls-efficacy status and changes in fall risk factors following two interventions. METHOD: Fifty-four older adults with hip osteoarthritis and at least one risk factor for falls received aquatic exercise twice weekly plus education once weekly (EE) or aquatic exercise only, twice weekly (EO), for 11 weeks. RESULTS: EE participants with low baseline falls efficacy demonstrated significantly (p<0.05) greater improvement in balance and falls efficacy compared to EE participants with high baseline falls efficacy. In the EE group only, baseline falls-efficacy status (low vs. high median split on the Activities-specific Balance Confidence Scale) was significantly (p<0.05) correlated with positive balance and falls-efficacy change scores (Spearman rank r=0.45 and 0.63 respectively). CONCLUSIONS: Individuals with one or more fall-risk factors and low falls efficacy may benefit from receiving an intervention that combines exercise with self-efficacy-enhancing education. Falls-efficacy screening may be important for decisions regarding referral to fall-prevention programmes.


Subject(s)
Accidental Falls , Osteoarthritis, Hip , Accidental Falls/prevention & control , Exercise , Exercise Therapy , Humans , Risk Factors
6.
Opt Express ; 15(21): 13913-23, 2007 Oct 17.
Article in English | MEDLINE | ID: mdl-19550663

ABSTRACT

Real time closed loop control of plasma assisted semiconductor manufacturing processes has received significant attention in recent years. Therefore we have developed and tested a customized optical sensor based on buffer gas (argon) actinometry which has been used to determine relative densities of atomic and molecular oxygen in an Ar/O(2) radio-frequency ICP chamber. The operation and accuracy of our optical sensor compared favorably with a high resolution commercial spectrometer but at lower cost and exhibited improved actinometric performance over a low resolution commercial spectrometer. Furthermore, threshold tests have been performed on the validity of buffer gas based actinometry in Ar/O(2) ICP plasmas where Ar is no longer a trace gas through Xe actinometry. The plasma conditions for which this customized optical sensor can be used for closed loop control have been established.

7.
Scanning ; 28(5): 259-66, 2006.
Article in English | MEDLINE | ID: mdl-17063764

ABSTRACT

Increasing concentrations of CO2 in the atmosphere are placing emphasis on the necessity for sequestering carbon (C) into soil organic matter (SOM). By studying the interior parts of soil aggregates, a better understanding of the incorporation and sequestration of plant residue materials within these aggregates could be obtained. The location of newly added plant residues within soil aggregates may also assist in the investigation of the impact of these newly added plant materials on soil aggregation. This study investigated two different techniques for determining the location of newly added plant residues within soil aggregates by using plant materials labelled with 14C and 13C isotopes incorporated into two different soil types, Black Earth (Pellic Vertisol) and Red Clay (Chromic Vertisol). Both autoradiography combined with scanning electron microprobe analysis (14C) and secondary ion mass spectrometry (SIMS) (13C) were successfully used for detecting the presence and location of the newly added plant residues fragments within soil aggregates of both soil types. The use of labelled plant materials is essential for the study of the location of newly added plant materials within soil aggregates, and this has proven to be a useful tool for studying the impact of residue additions on soil aggregate formation. Furthermore, these methods have been shown to be useful for determining the incorporation and sequestration of C materials within soil aggregates. The development of the 13C SIMS technique could alleviate the necessity for the use of the radioactive isotope 14C in soil studies.


Subject(s)
Carbon Radioisotopes/analysis , Environmental Monitoring/methods , Plants/chemistry , Soil/analysis , Microscopy, Electron, Scanning , Spectrometry, Mass, Secondary Ion
8.
Br J Cancer ; 95(6): 667-73, 2006 Sep 18.
Article in English | MEDLINE | ID: mdl-16967054

ABSTRACT

Addressing psychosocial and quality of life needs is central to provision of excellent care for people with advanced cancer. This study tested a brief nurse-delivered intervention to address the needs of urban women with advanced breast cancer. This study was conducted at four large urban hospitals in Australia. One hundred and five women with advanced breast cancer were recruited and randomised to receive the intervention or usual care, then asked to complete the European Organisation of Research and Treatment of Quality of life Q-C30 version (2.0) (EORTC Q-C30) (version 2) and Supportive Care Needs Survey (SCNS) at 1 month and 3 months postrecruitment. No significant differences were detected between intervention and usual care groups in the SCNS or the EORTC Q-C30 subscale scores. However, when the groups were divided into high needs (score of above 50) and low baseline needs (score of 50 or below) for each SCNS subscale, a significant difference between intervention and usual care groups was found in the psychological/emotional subscale among women with high baseline needs. In conclusions, this study demonstrated that a face-to-face session and follow-up phone call with a breast care nurse significantly reduced the psychological and emotional needs of those with high initial needs. There was no evidence of the intervention influencing the quality of life; or perceived needs of women with low initial psychological/emotional needs or perceived needs in other domains. Possibly, the intervention was not sufficiently intense to achieve an effect.


Subject(s)
Breast Neoplasms/nursing , Breast Neoplasms/psychology , Needs Assessment , Nurse Practitioners , Oncology Nursing , Social Support , Adult , Aged , Aged, 80 and over , Australia , Breast Neoplasms/rehabilitation , Disease Progression , Female , Follow-Up Studies , Health Care Surveys , Hospitals, Urban , Humans , Middle Aged , Quality of Life , Surveys and Questionnaires/standards , Urban Population
9.
Scanning ; 28(3): 164-71, 2006.
Article in English | MEDLINE | ID: mdl-16878788

ABSTRACT

Increasing concentrations of CO2 in the atmosphere are placing emphasis on the necessity for sequestering carbon (C) into soil organic matter (SOM). By studying the interior parts of soil aggregates, a better understanding of the incorporation and sequestration of plant residue materials within these aggregates could be obtained. The location of newly added plant residues within soil aggregates may also assist in the investigation of the impact of these newly added plant materials on soil aggregation. This study investigated two different techniques for determining the location of newly added plant residues within soil aggregates by using plant materials labelled with 14C and 13C isotopes incorporated into two different soil types, Black Earth (Pellic Vertisol) and Red Clay (Chromic Vertisol). Both autoradiography combined with scanning electron microprobe analysis (14C) and secondary ion mass spectrometry (SIMS) (13C) were successfully used for detecting the presence and location of the newly added plant residues fragments within soil aggregates of both soil types. The use of labelled plant materials is essential for the study of the location of newly added plant materials within soil aggregates, and this has proven to be a useful tool for studying the impact of residue additions on soil aggregate formation. Furthermore, these methods have been shown to be useful for determining the incorporation and sequestration of C materials within soil aggregates. The development of the 13C SIMS technique could alleviate the necessity for the use of the radioactive isotope 14C in soil studies.


Subject(s)
Carbon Isotopes/analysis , Environmental Monitoring/methods , Plants/chemistry , Soil/analysis , Spectrometry, Mass, Secondary Ion/methods , Carbon Radioisotopes/analysis , Microscopy, Electron, Scanning
10.
Eur J Cancer Care (Engl) ; 14(3): 211-22, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15952965

ABSTRACT

Enhancing quality of life and reducing the unmet needs of women are central to the successful management of advanced breast cancer. The objective of this study was to investigate the quality of life and support and information needs of urban women with advanced breast cancer. This study was conducted at four large urban hospitals in Melbourne, Australia. A consecutive sample of 105 women with advanced breast cancer completed a questionnaire that contained the European Organization of Research and Treatment of Cancer Quality of Life Q-C30 and the Supportive Care Needs Survey. Between one quarter and a third of the women reported difficulties with their physical, role and social functioning, and a little over a quarter of the women reported poor global health status. Fatigue was a problem for most women. The highest unmet needs were in the psychological and health information domains. Almost no differences in unmet needs were detected when comparing different demographic and disease characteristics of women. Health care providers should routinely monitor the quality of life and needs of women with advanced breast cancer to ensure that appropriate treatment, information or supportive services are made available.


Subject(s)
Breast Neoplasms/rehabilitation , Needs Assessment , Quality of Life , Adaptation, Psychological , Adult , Aged , Aged, 80 and over , Breast Neoplasms/psychology , Carcinoma, Ductal, Breast/psychology , Carcinoma, Ductal, Breast/rehabilitation , Carcinoma, Ductal, Breast/secondary , Female , Health Services Needs and Demand , Health Status , Humans , Middle Aged , Neoplasm Metastasis , Patient Education as Topic/methods , Pilot Projects , Social Support , Surveys and Questionnaires , Urban Health
11.
Bone Marrow Transplant ; 36(5): 437-41, 2005 Sep.
Article in English | MEDLINE | ID: mdl-15980879

ABSTRACT

We treated 17 patients with refractory (n = 7) or relapsed lymphoid malignancy (n = 10) following allogeneic HSCT with donor lymphocyte infusions (DLI). Patients with low-grade disease received DLI alone (n = 7) or following radiotherapy (n = 1). Patients with aggressive disease (n = 9) received prior chemotherapy. Nine out of 15 patients receiving DLI from sibling donors responded after one (n = 6), two (n = 2) and three (n = 1) infusions. Both MUD recipients achieved CR after two and three DLI. In all, 10/17 patients achieved CR including 3/4 patients with chronic lymphatic leukaemia (CLL), 4/4 with mantle cell lymphoma (MCL), 3/4 with follicular NHL but 0/5 with aggressive NHL/Richters. The median CD3 cell dose to achieve CR for siblings was 2 x 10(7)/kg. One patient with CLL had a second transplant following DLI-induced aplasia and is in CR at 14 months giving a final CR rate of 64%. Grade II-IV acute GVHD developed in 45% and chronic GVHD in 8/9 evaluable patients. Of the 11 patients finally achieving CR, one patient with MCL relapsed at 18 months post-DLI but all others remain in remission with a median follow-up of 40 months (range 12-64 months). Low-grade NHL and MCL have a high response rate and sustained remissions following DLI. Aggressive disease responds poorly however, despite pre-DLI chemotherapy.


Subject(s)
Graft vs Host Disease/therapy , Hematopoietic Stem Cell Transplantation , Living Donors , Lymphocyte Transfusion , Lymphoproliferative Disorders/therapy , T-Lymphocytes/transplantation , Adult , Female , Graft vs Host Disease/mortality , Humans , Lymphocyte Transfusion/methods , Lymphoproliferative Disorders/mortality , Male , Middle Aged , Neoplasm, Residual , Radiotherapy , Recurrence , Remission Induction , Retrospective Studies , Transplantation, Homologous
12.
Vaccine ; 22(21-22): 2722-9, 2004 Jul 29.
Article in English | MEDLINE | ID: mdl-15246603

ABSTRACT

Heterologous prime-boost vaccination schedules employing TA-HPV, a vaccinia virus encoding HPV 16/18 E6 and E7, in combination with TA-CIN, an HPV 16 L2E6E7 fusion protein, may offer advantages over the use of either agent alone for the immunotherapy of human papillomavirus (HPV) type 16-associated vulval intraepithelial neoplasia (VIN). In the present study, 10 women with HPV 16-positive high grade VIN, previously primed with TA-HPV, received three booster immunisations with TA-CIN. All but one demonstrated HPV 16-specific proliferative T-cell and/or serological responses following vaccination. Three patients additionally showed lesion shrinkage or symptom relief, but no direct correlation between clinical and immunological responses was seen.


Subject(s)
Cancer Vaccines/immunology , Immunization, Secondary , Papillomaviridae/immunology , Uterine Cervical Dysplasia/immunology , Vaccinia virus/immunology , Adult , Cancer Vaccines/adverse effects , Cell Division , DNA, Viral/analysis , Enzyme-Linked Immunosorbent Assay , Female , Glutathione Transferase/immunology , Humans , Immunity, Cellular/physiology , Immunization Schedule , Immunoglobulin G/analysis , Immunoglobulin G/biosynthesis , Interferon-gamma/metabolism , Phytohemagglutinins/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Vulva/pathology , Uterine Cervical Dysplasia/pathology
14.
J Pharm Biomed Anal ; 28(2): 199-208, 2002 Apr 15.
Article in English | MEDLINE | ID: mdl-11929662

ABSTRACT

A quantitative method for the analysis of AL-5848, the (+)-enantiomer of fluprostenol (FP), in human plasma is described. Plasma was spiked with a tetradeuterated analog of travoprost free acid (AL-5848X) as internal standard (IS) and acidified with 0.1 M formic acid. Sample clean up was performed using reversed phase solid-phase extraction. Following elution of the compounds of interest and evaporation to dryness, the residue was reconstituted in methanol:water (1:1) and chromatographed on an octadecylsilica (C18) column with negative ion electrospray ionization tandem mass spectrometry. The [M[bond]H](-) ions at m/z 457 and 461 for the analyte and IS, respectively, were subjected to collisional fragmentation with argon to yield the same intense 3-trifluoromethylphenolate (m/z 161) product ion. The validated concentration range was 0.010-3.00 ng/ml based on a 1.0 ml plasma aliquot. Fully adequate accuracy, precision, specificity, recovery and stability for routine use in clinical pharmacokinetic studies were demonstrated. Analysis of a second plasma aliquot following incubation with rabbit esterase allows the isopropyl ester pro-drug, travoprost (AL-6221), to be determined by difference.


Subject(s)
Antihypertensive Agents/blood , Cloprostenol/blood , Administration, Topical , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/pharmacokinetics , Calibration , Chromatography, High Pressure Liquid , Cloprostenol/administration & dosage , Cloprostenol/analogs & derivatives , Cloprostenol/pharmacokinetics , Deuterium , Humans , Indicators and Reagents , Quality Control , Reference Standards , Reproducibility of Results , Solvents , Spectrometry, Mass, Electrospray Ionization , Travoprost
15.
J Am Coll Nutr ; 20(5): 502-9, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11601565

ABSTRACT

OBJECTIVE: We examined the relationship between self-reported calcium (Ca) intake and bone mineral content (BMC) in children and adolescents. We hypothesized that an expression of Ca adjusted for energy intake (EI), i.e., Ca density, would be a better predictor of BMC than unadjusted Ca because of underreporting of EI. METHODS: Data were obtained on dietary intakes (repeated 24-hour recalls) and BMC (by DEXA) in a cross-section of 227 children aged 8 to 17 years. Bivariate and multivariate analyses were used to examine the relationship between Ca. Ca density, and the dependent variables total body BMC and lumbar spine BMC. Covariates included were height, weight, bone area. maturity age, activity score and EI. RESULTS: Reported EI compared to estimated basal metabolic rate suggested underreporting of EI. Total body and lumbar spine BMC were significantly associated with EI, but not Ca or Ca density, in bivariate analyses. After controlling for size and maturity, multiple linear regression analysis revealed unadjusted Ca to be a predictor of BMC in males in the total body (p = 0.08) and lumbar spine (p = 0.01)). Unadjusted Ca was not a predictor of BMC at either site in females. Ca density was not a better predictor of BMC at either site in males or females. CONCLUSIONS: The relationship observed in male adolescents in this study between Ca intake and BMC is similar to that seen in clinical trials. Ca density did not enable us to see a relationship between Ca intake and BMC in females, which may reflect systematic reporting errors or that diet is not a limiting factor in this group of healthy adolescents.


Subject(s)
Bone Density/physiology , Calcium, Dietary/administration & dosage , Absorptiometry, Photon/methods , Adolescent , Anthropometry , Bone and Bones/chemistry , Calcium, Dietary/metabolism , Child , Cross-Sectional Studies , Energy Intake , Female , Humans , Longitudinal Studies , Male , Mental Recall , Nutrition Assessment , Self Disclosure , Sex Characteristics
16.
Best Pract Res Clin Obstet Gynaecol ; 15(5): 783-99, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11563873

ABSTRACT

Cervical cancer is the second most common cause of cancer-related death in women, in some developing countries accounting for the highest cancer mortality. The evidence for the association of high-risk human papillomavirus types with the aetiology of cervical neoplasia is firmly established, human papillomavirus being detected in virtually all cervical cancers. The risk of progression of precursor cervical intra-epithelial neoplasia lesions is associated with persistence of human papillomavirus infection. One strategy for the management of cervical neoplasia worldwide could be the development of prophylactic and/or therapeutic human papillomavirus vaccines. This chapter will discuss the natural history of human papillomavirus infection, viral immunity and the clinical course of resultant disease as the background to the effective design and use of human papillomavirus vaccines for protection or therapy. The progress of ongoing phase I and II clinical trials for several different vaccine preparations and the challenges for establishing their future use will be discussed.


Subject(s)
Papillomaviridae/immunology , Papillomavirus Infections/therapy , Papillomavirus Vaccines , Tumor Virus Infections/therapy , Uterine Cervical Neoplasms/therapy , Viral Vaccines , Female , Humans , Papillomavirus Infections/complications , Tumor Virus Infections/complications , Uterine Cervical Neoplasms/immunology , Uterine Cervical Neoplasms/virology
17.
Dev Med Child Neurol ; 42(5): 334-9, 2000 May.
Article in English | MEDLINE | ID: mdl-10855654

ABSTRACT

Bone-mineral content (BMC; g) and density (BMD; g/cm2) were measured by dual energy X-ray absorptiometry in the proximal femur, femoral neck, and total body of nutritionally adequate children (n=17; 11 girls, six boys; aged 7.6 to 13.8 years) with spastic cerebral palsy (CP). Bone-mineral-free lean tissue (BMFL; g) and fat mass (FM; g) were obtained from total body scans. Chronological and developmental age-based z scores for the children with CP were derived from a pediatric database (n=894). Children with CP had BMC z scores from -1.8 (total body) to -3.2 (femoral neck) SDs below the normative sample. Non-independent ambulators had lower z scores for total body BMD, femoral neck BMD, and BMC than independent ambulators. The BMFL z score of individuals with CP was 2 SDs below that of the reference group and higher in the independent ambulators than in the non-independent ambulators, whereas FM deviated little. These findings suggest that non-nutritional factors, such as ambulation, account for the low BMC, BMD, and BMFL tissue observed in this population.


Subject(s)
Body Composition , Bone Density/physiology , Cerebral Palsy/physiopathology , Child Nutritional Physiological Phenomena , Locomotion/physiology , Absorptiometry, Photon , Adolescent , Anthropometry , Child , Female , Humans , Male , Reference Values , Risk Factors
18.
J Bone Miner Res ; 14(10): 1672-9, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10491214

ABSTRACT

To investigate the influence of physical activity on bone mineral accrual during the adolescent years, we analyzed 6 years of data from 53 girls and 60 boys. Physical activity, dietary intakes, and anthropometry were measured every 6 months and dual-energy X-ray absorptiometry scans of the total body (TB), lumbar spine (LS), and proximal femur (Hologic 2000, array mode) were collected annually. Distance and velocity curves for height and bone mineral content (BMC) were fitted for each child at several skeletal sites using a cubic spline procedure, from which ages at peak height velocity (PHV) and peak BMC velocity (PBMCV) were identified. A mean age- and gender-specific standardized activity (Z) score was calculated for each subject based on multiple yearly activity assessments collected up until age of PHV. This score was used to identify active (top quartile), average (middle 2 quartiles), or inactive (bottom quartile) groups. Two-way analysis of covariance, with height and weight at PHV controlled for, demonstrated significant physical activity and gender main effects (but no interaction) for PBMCV, for BMC accrued for 2 years around peak velocity, and for BMC at 1 year post-PBMCV for the TB and femoral neck and for physical activity but not gender at the LS (all p < 0.05). Controlling for maturational and size differences between groups, we noted a 9% and 17% greater TB BMC for active boys and girls, respectively, over their inactive peers 1 year after the age of PBMCV. We also estimated that, on average, 26% of adult TB bone mineral was accrued during the 2 years around PBMCV.


Subject(s)
Bone Density/physiology , Bone Development/physiology , Exercise/physiology , Absorptiometry, Photon , Adolescent , Anthropometry , Calcium, Dietary/pharmacology , Child , Female , Femur Neck/growth & development , Humans , Longitudinal Studies , Lumbar Vertebrae/growth & development , Male , Saskatchewan , Sex Characteristics
19.
J Pediatr ; 133(5): 682-7, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9821429

ABSTRACT

BACKGROUND AND OBJECTIVES: The greatest increase in bone mineral content occurs during adolescence. The amount of bone accrued may significantly affect bone mineral status in later life. We carried out a longitudinal investigation of the magnitude and timing of peak bone mineral content velocity (PBMCV) in relation to peak height velocity (PHV) and the age at menarche in a group of adolescent girls over a 6-year period. METHODS: The 53 girls in this study are a subset of the 115 girls (initially 8 to 16 years) in a 6-year longitudinal study of bone mineral accretion. The ages at PBMCV and PHV were determined by using a cubic spline curve fitting procedure. Determinations were based on height (n = 12) and bone (n = 6) measurements over 6 years. RESULTS: The timing of PBMCV and menarche were coincident, preceded approximately 1 year earlier by PHV. Correlation showed a negative relationship between age at menarche and both peak bone mineral accrual (r = -0.42, P < .002) and PHV (r = -0.45, P < .001). CONCLUSIONS: This longitudinal study demonstrated the close association between age at PBMCV and age at menarche and confirmed the relationship between greater PBMCV and PHV in earlier, as compared with later, maturing girls.


Subject(s)
Bone Density/physiology , Menarche/physiology , Adolescent , Body Height/physiology , Child , Female , Humans , Longitudinal Studies , Reference Values
20.
Med Sci Sports Exerc ; 29(11): 1395-9, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9372472

ABSTRACT

Maximization of bone accrual during the growing years is thought to be an important factor in minimizing fracture risk in old age. Mechanical loading through physical activity has been recommended as a modality for the conservation of bone mineral in adults; however, few studies have evaluated the impact of different loading regimes in growing children. The purpose of this study was to compare bone mineral density (BMD) in weight-bearing and non-weight-bearing limbs in 17 children with unilateral Legg Calvé Perthes Disease (LCPD). Children with this condition have an altered weight-bearing pattern whereby there is increased mechanical loading on the noninvolved normal hip and reduced loading on the involved painful hip. Thus, these children provide a unique opportunity to study the impact of differential mechanical loading on BMD during the growing years while controlling for genetic disposition. BMD at four regions of the proximal femur (trochanter, intertrochanter, femoral neck, total of the regions) was measured using dual energy x-ray absorptiometry (DXA), and the values were compared between the involved and noninvolved sides of the children with LCPD. The BMD of the both sides also were compared with normative values based on both chronological and skeletal age data. A significantly higher BMD was found on the noninvolved side over the involved side for all regions (P < 0.01 and percentage differences of 12-15%) except at the femoral neck (percentage difference of 3.9%). The BMD (at all regions) of the noninvolved side also was significantly greater (P < 0.01) than either the chronological or skeletal age based norms for all sites except the trochanter. The results support the concept that mechanical loading of the skeleton during the growing years is an important factor in BMD accrual.


Subject(s)
Bone Density , Femur/physiopathology , Legg-Calve-Perthes Disease/physiopathology , Absorptiometry, Photon , Adolescent , Biomechanical Phenomena , Child , Exercise , Female , Femoral Fractures/etiology , Femoral Fractures/prevention & control , Femur/growth & development , Humans , Male , Motor Activity , Risk Factors
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