Understanding the effect of mechanical forces on ovarian cancer progression

OBJECTIVE

Mechanical forces including tension, compression, and shear stress are increasingly implicated in tumor progression and metastasis. Understanding the mechanisms behind epithelial ovarian cancer (EOC) progression and metastasis is critical, and this study aimed to elucidate the effect of oscillatory and constant tension on EOC.

METHODS

SKOV-3 and OVCAR-8 EOC cell lines were placed under oscillatory tension for 3 days and compared to cells placed under no tension. Cell proliferation, migration, and invasion were analyzed while RNAseq and Western Blots helped investigate the biological mechanisms underlying the increasingly aggressive state of the experimental cells. Finally, in vivo experiments using SCID mice assisted in confirming the in vitro results.

RESULTS

Oscillatory tension (OT) and constant tension (CT) significantly increased SKOV-3 proliferation, while OT caused a significant increase in proliferative genes, migration, and invasion in this cell line. CT did not cause significant increases in these areas. Neither OT nor CT increased proliferation or invasion in OVCAR-8 cells, while both tension types significantly increased cellular migration. Two proteins involved in metastasis, E-cadherin and Snail, were both significantly affected by OT in both cell lines, with E-cadherin levels decreasing and Snail levels increasing. In vivo, tumor growth and weight for both cell types were significantly increased, and ascites development was significantly higher in the experimental OVCAR-8 group than in the control group.

CONCLUSIONS

This study found that mechanical forces are influential in EOC progression and metastasis. Further analysis of downstream mechanisms involved in EOC metastasis will be critical for improvements in EOC treatment.

25-Hydroxyvitamin D status, light exposure and sleep quality in UK dwelling South Asian and Caucasian postmenopausal women

There is a lack of research into 25-hydroxyvitamin D (25(OH)D) status, light exposure and sleep patterns in South Asian populations. In addition, results of research studies are conflicting as to whether there is an association between 25(OH)D status and sleep quality. We investigated 25(OH)D status, self-reported and actigraphic sleep quality in n = 35 UK dwelling postmenopausal women (n = 13 South Asians, n = 22 Caucasians), who kept daily sleep diaries and wore wrist-worn actiwatch (AWL-L) devices for 14 days. A subset of n = 27 women (n = 11 South Asian and n = 16 Caucasian) also wore a neck-worn AWL-L device to measure their light exposure. For 25(OH)D concentration, South Asians had a median ± IQR of 43.8 ± 28.2 nmol/L, which was significantly lower than Caucasians (68.7 ± 37.4 nmol/L)(P = 0.001). Similarly, there was a higher sleep fragmentation in the South Asians (mean ± SD 36.9 ± 8.9) compared with the Caucasians (24.7 ± 7.1)(P = 0.002). Non-parametric circadian rhythm analysis of rest/activity patterns showed a higher night-time activity (L5) (22.6 ± 14.0 vs. 10.5 ± 4.4; P = 0.0008) and lower relative amplitude (0.85 ± 0.07 vs. 0.94 ± 0.02; P < 0.0001) in the South Asian compared with the Caucasian women. More South Asians (50%) met the criteria for sleep disorders (PSQI score >5) than did Caucasians (27%) (P = 0.001, Fishers Exact Test). However, there was no association between 25(OH)D concentration and any sleep parameter measured (P > 0.05) in either ethnic group. South Asians spent significantly less time in illuminance levels over 200 lx (P = 0.009) than did Caucasians. Overall, our results show that postmenopausal South Asian women have lower 25(OH)D concentration than Caucasian women. They also have higher sleep fragmentation, as well as a lower light exposure across the day. This may have detrimental implications for their general health and further research into sleep quality and light exposure in the South Asian ethnic group is warranted.

Higher bone resorption excretion in South Asian women vs. White Caucasians and increased bone loss with higher seasonal cycling of vitamin D: Results from the D-FINES cohort study

Few data exist on bone turnover in South Asian women and it is not well elucidated as to whether Western dwelling South Asian women have different bone resorption levels to that of women from European ethnic backgrounds. This study assessed bone resorption levels in UK dwelling South Asian and Caucasian women as well as evaluating whether seasonal variation in 25-hydroxyvitamin D [25(OH)D] is associated with bone resorption in either ethnic group. Data for seasonal measures of urinary N-telopeptide of collagen (uNTX) and serum 25(OH)D were analysed from n=373 women (four groups; South Asian postmenopausal n=44, South Asian premenopausal n=50, Caucasian postmenopausal n=144, Caucasian premenopausal n=135) (mean (±SD) age 48 (14) years; age range 18-79years) who participated in the longitudinal D-FINES (Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England) cohort study (2006-2007). A mixed between-within subjects ANOVA (n=192) showed a between subjects effect of the four groups (P<0.001) on uNTX concentration, but no significant main effect of season (P=0.163). Bonferroni adjusted Post hoc tests (P≤0.008) suggested that there was no significant difference between the postmenopausal Asian and premenopausal Asian groups. Season specific age-matched-pairs analyses showed that in winter (P=0.04) and spring (P=0.007), premenopausal Asian women had a 16 to 20nmolBCE/mmol Cr higher uNTX than premenopausal Caucasian women. The (amplitude/mesor) ratio (i.e. seasonal change) for 25(OH)D was predictive of uNTX, with estimate (SD)=0.213 (0.015) and 95% CI (0.182, 0.245; P<0.001) in a non-linear mixed model (n=154). This showed that individuals with a higher seasonal change in 25(OH)D, adjusted for overall 25(OH)D concentration, showed increased levels of uNTX. Although the effect size was smaller than for the amplitude/mesor ratio, the mesor for 25(OH)D concentration was also predictive of uNTX, with estimate (SD)=-0.035 (0.004), and 95% CI (-0.043, -0.028; P<0.001). This study demonstrates higher levels of uNTX in premenopausal South Asian women than would be expected for their age, being greater than same-age Caucasian women, and similar to postmenopausal Asian women. This highlights potentially higher than expected bone resorption levels in premenopausal South Asian women which, if not offset by concurrent increased bone formation, may have future clinical and public health implications which warrant further investigation. Individuals with a larger seasonal change in 25(OH)D concentration showed an increased bone resorption, an association which was larger than that of the 25(OH)D yearly average, suggesting it may be as important clinically to ensure a stable and steady 25(OH)D concentration, as well as one that is high enough to be optimal for bone health.

Concurrent beneficial (vitamin D production) and hazardous (cutaneous DNA damage) impact of repeated low-level summer sunlight exposures

Background

The concurrent impact of repeated low‐level summer sunlight exposures on vitamin D production and cutaneous DNA damage, potentially leading to mutagenesis and skin cancer, is unknown.

Objectives

This is an experimental study (i) to determine the dual impact of repeated low‐level sunlight exposures on vitamin D status and DNA damage/repair (via both skin and urinary biomarkers) in light‐skinned adults; and (ii) to compare outcomes following the same exposures in brown‐skinned adults.

Methods

Ten white (phototype II) and six South Asian volunteers (phototype V), aged 23–59 years, received 6 weeks’ simulated summer sunlight exposures (95% ultraviolet A/5% ultraviolet B, 1·3 standard erythemal doses three times weekly) wearing summer clothing exposing ~35% body surface area. Assessments made were circulating 25‐hydroxyvitamin D [25(OH)D], immunohistochemistry for cyclobutane pyrimidine dimer (CPD)‐positive nuclei and urinary biomarkers of direct and oxidative (8‐oxo‐deoxyguanosine) DNA damage.

Results

Serum 25(OH)D rose from mean 36·5 ± 13·0 to 54·3 ± 10·5 nmol L⁻¹ (14·6 ± 5·2 to 21·7 ± 4·2 ng mL⁻¹) in phototype II vs. 17·2 ± 6·3 to 25·5 ± 9·5 nmol L⁻¹ (6·9 ± 2·5 to 10·2 ± 3·8 ng mL⁻¹) in phototype V (P < 0·05). Phototype II skin showed CPD‐positive nuclei immediately postcourse, mean 44% (range 27–84) cleared after 24 h, contrasting with minimal DNA damage and full clearance in phototype V (P < 0·001). The findings did not differ from those following single ultraviolet radiation (UVR) exposure. Urinary CPDs remained below the detection threshold in both groups; 8‐oxo‐deoxyguanosine was higher in phototype II than V (P = 0·002), but was unaffected by UVR.

Conclusions

Low‐dose summer sunlight exposures confer vitamin D sufficiency in light‐skinned people concurrently with low‐level, nonaccumulating DNA damage. The same exposures produce minimal DNA damage but less vitamin D in brown‐skinned people. This informs tailoring of sun‐exposure policies.

What's already known about this topic?

Repeated low‐level exposures to simulated U.K. sunlight can produce vitamin D sufficiency in light‐skinned people, but the concurrent impact on cutaneous DNA damage is unknown.

What does this study add?

Low‐level simulated sunlight exposures in people of skin phototype II conferred vitamin D sufficiency concurrently with DNA damage, which showed partial clearance at 24 h and no evidence of accumulated damage after 6 weeks of exposures.

The same exposures produced minimal DNA damage but less vitamin D in brown‐skinned people (phototype V).

The findings are informative for sun‐exposure guidance.

Plain language summary available online

Low serum 25-hydroxyvitamin D is associated with increased risk of stress fracture during Royal Marine recruit training

The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training. Poor vitamin D status was associated with an increased risk of stress fracture. Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status.

INTRODUCTION

Stress fracture is a common overuse injury in military recruits, including Royal Marine (RM) training in the UK. RM training is recognised as one of the most arduous basic training programmes in the world. Associations have been reported between serum 25-hydroxyvitamin D (25(OH)D) and risk of stress fracture, but the threshold of 25(OH)D for this effect remains unclear. We aimed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training.

METHODS

We prospectively followed 1082 RM recruits (males aged 16-32 years) through the 32-week RM training programme. Troops started training between September and July. Height, body weight and aerobic fitness were assessed at week 1. Venous blood samples were drawn at weeks 1, 15 and 32. Serum samples were analysed for 25(OH)D and parathyroid hormone (PTH).

RESULTS

Seventy-eight recruits (7.2 %) suffered a total of 92 stress fractures. Recruits with a baseline serum 25(OH)D concentration below 50 nmol L(-1) had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold (χ(2) (1) = 3.564, p = 0.042; odds ratio 1.6 (95 % confidence interval (CI) 1.0-2.6)). Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L(-1) in February, to 97.3 ± 24.6 nmol L(-1) in July (overall mean 69.2 ± 29.2 nmol L(-1), n = 1016). There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 (r = -0.209, p < 0.001) and week 32 (r = -0.214, p < 0.001), but not at baseline.

CONCLUSION

Baseline serum 25(OH)D concentration below 50 nmol L(-1) was associated with an increased risk of stress fracture. Further studies into the effects of vitamin D supplementation on stress fracture risk are certainly warranted.

Automated immunoassays for 25-hydroxyvitamin D (25-OHD): do plasticisers interfere?

The international quality assessment scheme for vitamin D metabolites (DEQAS) was established in 1989. The scheme involves the quarterly distribution of 5 serum samples prepared from blood collected in plain plastic bags. Following transfer of the donors to a clinic using different bags, sera were found to contain a contaminant that interfered in both the local LC-MS/MS assay and the NIST reference measurement procedure for 25-OHD. It seemed likely that the contaminant was a substance, possibly a plasticiser, leached from the plastic bag. It was subsequently suggested that the unidentified contaminant might also cause interference in certain automated non-extraction assays for 25-OHD. This was investigated in 3 automated immunoassays by comparing serum 25-OHD results from blood collected simultaneously into plain glass tubes and plastic bags. There was no significant difference in results, indicating that the leached substance had no effect on any of the 3 immunoassays examined.

Ethnicity and social deprivation contribute to vitamin D deficiency in an urban UK population

We receive a large number of 25 hydroxyvitamin D (25OHD) assay requests from General Medical Practitioners (GPs) in primary care. We have investigated whether this rate of requesting is related to the ethnicity of the local urban population based in Central Manchester or Trafford areas with very different ethnic populations. Data on assay requesting was collected from January-December 2013. Samples were assayed using an ABSciex 5500 tandem mass spectrophotometer and the Chromsystems 25OHD kit for LC-MS/MS. 11,291 requests for 25OHD measurement received from Central Manchester GPs and 5176 requests from Trafford GPs. Overall 29% of patients were profoundly deficient (<25nmol/L) and a further 32% were insufficient (25-50nmol/L). Using the 2011 Census data we have analysed our data by ethnicity (categorized here as white, Asian, black, Chinese, other) based on patient's home postcode and related this to the Index of Multiple Deprivation (IMD). In areas where >70% of the population were non-white (NW), 69% had 25OHD <50nmol/L. Areas where <5% of patients were NW, 42% of patients were still insufficient. There was a significant correlation between the Index of Social Deprivation (IMD) and the percentage of patients with 25OHD <50nmol/L (p<0.0001). Areas with the highest Index of Social Deprivation (IMD ranking <16,000) showed no association between ethnicity and IMD (p=0.69). We have shown that over 61% of all patients in these urban areas of Manchester and Trafford showed increased risk of bone, and potentially other diseases, based on their 25OHD assay results alone and that social deprivation, as well as ethnicity, contribute to the poor 25OHD levels seen in these patients.

Sunlight exposure behaviour and vitamin D status in photosensitive patients: longitudinal comparative study with healthy individuals at U.K. latitude

BACKGROUND

Low vitamin D status is prevalent in wintertime in populations at northerly latitudes. Photosensitive patients are advised to practise sun avoidance, but their sunlight exposure levels, photoprotective measures and resulting vitamin D status are unknown.

OBJECTIVES

To examine seasonal vitamin D status in photosensitive patients relative to healthy individuals and to assess quantitatively behavioural and demographic contributors.

METHODS

This was a longitudinal prospective cohort study (53·5°N) examining year-round 25-hydroxyvitamin D [25(OH)D] levels, sun-exposure behaviour and oral vitamin D intake in photosensitive patients diagnosed at a photoinvestigation unit (n = 53), compared with concurrently assessed healthy adults (n = 109).

RESULTS

Photosensitive patients achieved seasonal 25(OH)D variation, but insufficient (< 20 ng mL(-1); 50 nmol L(-1)) and even deficient (< 10 ng mL(-1); 25 nmol L(-1)) levels occurred at the summer peak in 47% and 9% of patients, respectively, rising to 73% and 32% at the winter trough. Adjusting for demographic factors, the mean values were lower than for healthy volunteers by 18% [95% confidence interval (CI) 4-29] in summer (P = 0·02) and 25% (95% CI 7-39) in winter (P = 0·01). Behavioural factors explained 25(OH)D differences between cohorts. Patients demonstrated lower weekend ultraviolet B doses (P < 0·001), smaller skin surface area exposure (P = 0·004) and greater sunscreen use (P < 0·001), while average oral vitamin D intake was low in both groups (photosensitive: 2·94 μg per day). Supplementation and summer surface area exposure predicted summer peak and winter trough 25(OH)D levels. A 1 μg per day increment in supplementary vitamin D raised summer and winter 25(OH)D by 5% (95% CI 3-7) and 9% (95% CI 5-12), respectively (both P < 0·001).

CONCLUSIONS

Photosensitive patients are, through their photoprotective measures, at high risk of year-round low vitamin D status. Guidance on oral measures should target this patient group and their physicians.

Sunlight exposure and photoprotection behaviour of white Caucasian adolescents in the UK

BACKGROUND

Sun exposure has positive and negative effects on health, yet little is known about the sun exposure behaviour of UK adolescents, including those more prone or less prone to sunburn.

OBJECTIVE

To examine sun exposure behaviour of UK white Caucasian adolescents including time spent outdoors, holiday behaviour, use of sunscreen and clothing, with assessment for differences between sun-reactive skin type groups.

METHODS

White Caucasian adolescents (12-15 years) attending schools in Greater Manchester completed a two-page questionnaire to assess sun exposure and photoprotective behaviour.

RESULTS

A total of 133 adolescents (median age 13.4 years; 39% skin type I/II, 61% skin type III/IV) completed the questionnaire. In summer, adolescents spent significantly longer outdoors at weekends (median 4 h/day, range 0.25-10) than on weekdays (2, 0.25-6; P < 0.0001). When at home in the UK during summer, 44% reported never wearing sunscreen compared to just 1% when on a sunny holiday. Sunscreen use was also greater (frequency/coverage) when on a sunny holiday than at home in the UK summer (P < 0.0001). Adolescents of skin types I/II (easy burning) spent significantly less time outdoors than skin types III/IV (easy tanning) on summer weekends (P < 0.001), summer weekdays (P < 0.05) and on a sunny holiday (P = 0.001). Furthermore, skin types I/II reported greater sunscreen use during summer in the UK and on sunny holiday (both P < 0.01), and wore clothing covering a greater skin area on a sunny holiday (P < 0.01) than skin types III/IV. There was no difference in sun exposure behaviour/protection between males and females.

CONCLUSION

The greater sun-protective measures reported by adolescents of sun-reactive skin type group I/II than III/IV suggest those who burn more easily are aware of the greater need to protect their skin. However, use of sunscreen during the UK summer is low and may need more effective promotion in adolescents.

Lifestyle factors including less cutaneous sun exposure contribute to starkly lower vitamin D levels in U.K. South Asians compared with the white population

BACKGROUND

Long-standing concerns over the vitamin D status of South Asian adults in the U.K. require studies using statistically valid sample sizes to measure annual variation and contributory lifestyle factors.

OBJECTIVES

To measure annual variation in the vitamin D status of U.K. South Asians, to determine the associated lifestyle influences, and to compare these with a similar study of white adults.

METHODS

A single-centre, prospective cohort study measuring circulating 25-hydroxyvitamin D [25(OH)D], sunlight exposure levels and lifestyle factors for 1 year in 125 ambulant South Asian adults with sun-reactive skin type V, aged 20-60 years, in Greater Manchester, U.K. (53·5°N).

RESULTS

The 25(OH)D levels of South Asians were alarmingly low. In summer, their median 25(OH)D level was 9·0 ng mL(-1) , [interquartile range (IQR) 6·7-13·1], falling to 5·8 ng mL(-1) (IQR 4·0-8·1) in winter. This compared with values in the white population of 26·2 ng mL(-1) (IQR 19·9-31·5) in summer and 18·9 ng mL(-1) IQR (11·6-23·7) in winter. Median daily dietary vitamin D was lower in South Asians (1·32 μg vs. 3·26 μg for white subjects) and was compounded by low supplement use. Despite similar times spent outdoors, ultraviolet (UV) dosimeters recorded lower personal UV exposure among South Asians, indicating sun avoidance when outside, while sun exposure diaries recorded lower amounts of skin surface exposure.

CONCLUSIONS

The majority of South Asians never reached sufficiency in vitamin D status. Lifestyle differences, with lower oral intake, sun exposure and rates of cutaneous production due to darker skin, indicate that standard advice on obtaining sufficient vitamin D needs modification for the South Asian community in the U.K.

Greater seasonal cycling of 25-hydroxyvitamin D is associated with increased parathyroid hormone and bone resorption

SUMMARY

This analysis assessed whether seasonal change in 25-hydroxyvitamin D concentration was associated with bone resorption, as evidenced by serum parathyroid hormone and C-terminal telopeptide concentrations. The main finding was that increased seasonal fluctuation in 25-hydroxyvitamin D was associated with increased levels of parathyroid hormone and C-terminal telopeptide.

INTRODUCTION

It is established that adequate 25-hydroxyvitamin D (25(OH)D, vitamin D) concentration is required for healthy bone mineralisation. It is unknown whether seasonal fluctuations in 25(OH)D also impact on bone health. If large seasonal fluctuations in 25(OH)D were associated with increased bone resorption, this would suggest a detriment to bone health. Therefore, this analysis assessed whether there is an association between seasonal variation in 25(OH)D and bone resorption.

METHODS

The participants were (n = 279) Caucasian and (n = 88) South Asian women (mean (±SD); age 48.2 years (14.4)) who participated in the longitudinal Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England study (2006-2007). The main outcomes were serum 25(OH)D, serum parathyroid hormone (sPTH) and serum C-terminal telopeptide of collagen (sCTX), sampled once per season for each participant.

RESULTS

Non-linear mixed modelling showed the (amplitude/mesor) ratio for seasonal change in log 25(OH)D to be predictive of log sPTH (estimate = 0.057, 95 % CI (0.051, 0.063), p < 0.0001). Therefore, individuals with a higher seasonal change in log 25(OH)D, adjusted for overall log 25(OH)D concentration, showed increased levels of log sPTH. There was a corresponding significant ability to predict the range of seasonal change in log 25(OH)D through the level of sCTX. Here, the corresponding parameter statistics were estimate = 0.528, 95 % CI (0.418, 0.638) and p ≤ 0.0001.

CONCLUSIONS

These findings suggest a possible detriment to bone health via increased levels of sPTH and sCTX in individuals with a larger seasonal change in 25(OH)D concentration. Further larger cohort studies are required to further investigate these preliminary findings.

Bone marrow levels of 25 hydroxy vitamin D are not depressed in cases of hip fracture compared with controls

There is little information on tissue as distinct from plasma levels of vitamin D metabolites in cases of hip fracture compared with controls. Femoral neck fractures in the elderly are associated with increased cortical remodelling and endosteal resorption, leading to regional increases in porosity and reduced cortical thickness. Vitamin D metabolites play a central role in the maintenance of normal serum calcium levels and may, through interactions with parathyroid hormone, exert an important influence on bone structure. To investigate whether hip fracture might be associated with tissue vitamin D deficiency, we have measured by radioimmunoassay the levels of 25 hydroxy vitamin D (25 (OH)D) in bone marrow samples extracted from the proximal femurs of 16 female subjects who had suffered fracture (mean age = 82.1 years, standard error (se) 1.9) and nine sex matched post mortem controls (mean age = 83.8 years, se 2.5). Twenty five (OH)D concentrations were significantly greater in the fracture cases (median = 3.7, IQR = 2.5-3.9 ng/g) than in the control group (median = 1.5, IQR = 0.9-2.3 ng/g; P = 0.0007, non-parametric Wilcoxon/Kruskal-Wallis test). It was suggested in the 1970s that bone loss and hip fracture risk in the UK were driven by vitamin D deficiency. Our results suggest that the alterations in femoral neck bone microstructure and remodelling in hip fracture cannot be assigned to the single cause of relative deficiency of vitamin D. Vitamin D deficiency or insufficiency may nevertheless increase remodelling and loss of bone tissue and contribute causally to a minority of hip fractures.

Vitamin D status and muscle function in children with neurofibromatosis type 1 (NF1)

OBJECTIVES

The aim of this cross-sectional study was to assess the vitamin D status and muscle function in children with NF1 compared with their unaffected siblings.

METHODS

NF1 children between 5 and 18 years of age and who had at least one unaffected sibling were identified. Serum concentrations of 25-hydroxyvitamin D (25(OH)D), calcium, inorganic phosphate, alkaline phosphate, parathyroid hormone and 1,25-dihydroxyvitamin D were measured. The Leonardo Mechanography Ground Reaction Force Platform (GRFP) was used to measure EFI, jump power, force and height.

RESULTS

There was no significant difference in 25(OH)D between NF1 subjects and unaffected siblings. Relative jump power and force were found to be significantly different. The adjusted means (95% confidence limits) of non-NF1 and NF1 children for relative jump power (W/kg), controlling for body mass and age, were 37.31 (34.14, 40.49) and 32.51 (29.34, 35.68), respectively (P=0.054); and force (N/kg), controlling for body mass, age and gender, were 25.79 (24.28, 27.30) and 21.12 (19.61, 22.63), respectively (P<0.0001). Jumping parameters were not related to serum 25(OH)D.

CONCLUSIONS

There was no significant relationship between vitamin D status and NF1 status in children. NF1 children had significantly impaired jumping power and force, when compared to their unaffected siblings.

Vitamin D deficiency in UK South Asian Women of childbearing age: a comparative longitudinal investigation with UK Caucasian women

SUMMARY

This is the first 1-year longitudinal study which assesses vitamin D deficiency in young UK-dwelling South Asian women. The findings are that vitamin D deficiency is extremely common in this group of women and that it persists all year around, representing a significant public health concern.

INTRODUCTION

There is a lack of longitudinal data assessing seasonal variation in vitamin D status in young South Asian women living in northern latitudes. Studies of postmenopausal South Asian women suggest a lack of seasonal change in 25-hydroxy vitamin D [25(OH)D], although it is unclear whether this is prevalent among premenopausal South Asians. We aimed to evaluate, longitudinally, seasonal changes in 25(OH)D and prevalence of vitamin D deficiency in young UK-dwelling South Asian women as compared with Caucasians. We also aimed to establish the relative contributions of dietary vitamin D and sun exposure in explaining serum 25(OH)D.

METHODS

This is a 1-year prospective cohort study assessing South Asian (n = 35) and Caucasian (n = 105) premenopausal women living in Surrey, UK (51° N), aged 20-55 years. The main outcome measured was serum 25(OH)D concentration. Secondary outcomes were serum parathyroid hormone, self-reported dietary vitamin D intake and UVB exposure by personal dosimetry.

RESULTS

Serum 25(OH)D <25 nmol/L was highly prevalent in South Asians in the winter (81 %) and autumn (79.2 %). Deficient status (below 50 nmol/L) was common in Caucasian women. Multi-level modelling suggested that, in comparison to sun exposure (1.59, 95 %CI = 0.83-2.35), dietary intake of vitamin D had no impact on 25(OH)D levels (-0.08, 95 %CI = -1.39 to 1.23).

CONCLUSIONS

Year-round vitamin D deficiency was extremely common in South Asian women. These findings pose great health threats regarding the adverse effects of vitamin D deficiency in pregnancy and warrant urgent vitamin D public health policy and action.

Sunlight and dietary contributions to the seasonal vitamin D status of cohorts of healthy postmenopausal women living at northerly latitudes: a major cause for concern?

We assessed sunlight and dietary contributions to vitamin D status in British postmenopausal women. Our true longitudinal 25-hydroxyvitamin D (25(OH)D) measurements varied seasonally, being lower in the north compared to the south and lower in Asian women. Sunlight exposure in summer and spring provided 80% total annual intake of vitamin D.

INTRODUCTION

Vitamin D deficiency is highlighted as a potential problem for countries at high latitude, but there are few true longitudinal, seasonal data to allow regional comparisons. We aimed to directly compare seasonal variation in vitamin D status (25(OH)D) in postmenopausal women at two northerly latitudes and to assess the relative contributions of sunlight exposure and diet.

METHODS

Vitamin D status was assessed in 518 postmenopausal women (age 55-70 years) in a two-centre cohort study with serum collected at fixed three-monthly intervals from summer 2006 for immunoassay measurement of 25(OH)D and parathyroid hormone. At 57° N (Aberdeen, Scotland, UK), there were 338 Caucasian women; at 51° N (Surrey, South of England, UK), there were 144 Caucasian women and 35 Asian women. UVB exposure (polysulphone film badges) and dietary vitamin D intakes (food diaries) were also estimated.

RESULTS

Caucasian women had lower 25(OH)D (p < 0.001) at 57° N compared to 51° N. Median (interquartile range) in nanomoles per litre for summer (June-August) at 57° N was 43.0 (20.9) and at 51° N was 62.5 (26.6) and for winter (December-February) at 57° N was 28.3 (18.9) and at 51° N was 39.9 (24.0). For Asian women at 51° N, median 25(OH)D was 24.0 (15.8) nmol/L in summer and 16.9 (15.9) nmol/L in winter. Median dietary vitamin D intakes were 80-100 IU for Caucasians and 50-65 IU for the Asian women. Sunlight was the main contributor to 25(OH)D with spring and summer providing >80% total annual intake.

CONCLUSIONS

These longitudinal data show significant regional and ethnic differences in UVB exposure and vitamin D status for postmenopausal women at northerly latitudes. The numbers of women who are vitamin D deficient is a major concern and public health problem.

Proceedings of the Rank Forum on Vitamin D

The Rank Forum on Vitamin D was held on 2nd and 3rd July 2009 at the University of Surrey, Guildford, UK. The workshop consisted of a series of scene-setting presentations to address the current issues and challenges concerning vitamin D and health, and included an open discussion focusing on the identification of the concentrations of serum 25-hydroxyvitamin D (25(OH)D) (a marker of vitamin D status) that may be regarded as optimal, and the implications this process may have in the setting of future dietary reference values for vitamin D in the UK. The Forum was in agreement with the fact that it is desirable for all of the population to have a serum 25(OH)D concentration above 25 nmol/l, but it discussed some uncertainty about the strength of evidence for the need to aim for substantially higher concentrations (25(OH)D concentrations>75 nmol/l). Any discussion of 'optimal' concentration of serum 25(OH)D needs to define 'optimal' with care since it is important to consider the normal distribution of requirements and the vitamin D needs for a wide range of outcomes. Current UK reference values concentrate on the requirements of particular subgroups of the population; this differs from the approaches used in other European countries where a wider range of age groups tend to be covered. With the re-emergence of rickets and the public health burden of low vitamin D status being already apparent, there is a need for urgent action from policy makers and risk managers. The Forum highlighted concerns regarding the failure of implementation of existing strategies in the UK for achieving current vitamin D recommendations.

A randomized, controlled trial of vitamin D supplementation upon musculoskeletal health in postmenarchal females

CONTEXT

There has been a resurgence of vitamin D deficiency rickets throughout the developed world, with infants and adolescents being primarily affected. Adolescence is a crucial period for muscle and bone mineral accumulation.

OBJECTIVE

The aim was to determine the effect of vitamin D supplementation on the adolescent musculoskeletal system.

DESIGN AND SETTING

We conducted a community-based, double-blind, randomized controlled trial in a secondary school.

PARTICIPANTS

Postmenarchal 12- to 14-yr-old females participated in the trial. Ninety-nine were screened, 73 were included in randomized controlled trial, and 69 completed the trial. There were no adverse events.

INTERVENTION

Four doses of 150,000 IU vitamin D(2) (ergocalciferol) were given over 1 yr.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and jumping mechanography were used.

RESULTS

At follow-up, 25-hydroxyvitamin D [25(OH)D] status was 56.0 ± 8.9 nmol/liter in the intervention group and 15.8 ± 6.6 nmol/liter in controls. There were no effects of supplementation on bone; however, for muscle function, efficiency of movement improved in the vitamin D-treated group. There was an interaction between baseline 25(OH)D concentration and response to vitamin D supplementation for muscle jump velocity.

CONCLUSIONS

Despite improvements in 25(OH)D status, treatment with vitamin D(2) was not shown to increase mineral accretion, bone geometry or strength, muscle force, or power. There were greater increases in jump velocity in girls with the lowest baseline 25(OH)D concentrations. Lack of effect of intervention after the period of peak mineral and muscle mass accretion suggests that earlier action is required.

The role of sunlight exposure in determining the vitamin D status of the U.K. white adult population

BACKGROUND

Vitamin D is necessary for bone health and is potentially protective against a range of malignancies. Opinions are divided on whether the proposed optimal circulating 25-hydroxyvitamin D [25(OH)D] level (≥ 32 ng mL⁻¹) is an appropriate and feasible target at population level.

OBJECTIVES

We examined whether personal sunlight exposure levels can provide vitamin D sufficient (≥ 20 ng mL⁻¹) and optimal status in the U.K. public.

METHODS

This prospective cohort study measured circulating 25(OH)D monthly for 12 months in 125 white adults aged 20-60 years in Greater Manchester. Dietary vitamin D and personal ultraviolet radiation (UVR) exposure were assessed over 1-2 weeks in each season. The primary analysis determined the post-summer peak 25(OH)D required to maintain sufficiency in wintertime.

RESULTS

Dietary vitamin D remained low in all seasons (median 3·27 μg daily, range 2·76-4·15) while personal UVR exposure levels were high in spring and summer, low in autumn and negligible in winter. Mean 25(OH)D levels were highest in September [28·4 ng mL⁻¹; 28% optimal, zero deficient (<5 ng mL⁻¹)], and lowest in February (18·3 ng mL⁻¹; 7% optimal, 5% deficient). A February 25(OH)D level of 20 ng mL⁻¹ was achieved following a mean (95% confidence interval) late summer level of 30·4 (25·6-35·2) and 34·9 (27·9-41·9) ng mL⁻¹ in women and men, respectively, with 62% of variance explained by gender and September levels.

CONCLUSIONS

Late summer 25(OH)D levels approximating the optimal range are required to retain sufficiency throughout the U.K. winter. Currently the majority of the population fails to reach this post-summer level and becomes vitamin D insufficient during the winter.

The impact of photosensitivity disorders on aspects of lifestyle

BACKGROUND

Photosensitivity disorders involve an abnormal skin reaction to sunlight exposure and affect a substantial percentage of the population. No previous studies have directly compared lifestyle attributes between photosensitive and healthy individuals.

OBJECTIVES

To assess the impact of photosensitivity on time spent outdoors in the U.K., holiday behaviour, use of sunscreens and vitamin D supplements, and employment status.

METHODS

Questionnaires were completed by ambulant photosensitive and healthy adults aged 18-60 years residing in Greater Manchester.

RESULTS

Forty-five adults with moderate-severe photosensitivity and 124 healthy adults completed the questionnaire. This revealed that photosensitive subjects spent significantly less time outdoors in the U.K. on both summer weekdays (P < 0·01) and summer weekends (P < 0·0001) than healthy subjects, took fewer holidays per year (P < 0·05), and spent less time outdoors on a sunny holiday (P < 0·0001). They wore clothing that covered a wider skin area (P < 0·0001), and use of sunscreen was greater (both frequency of application and area covered) in the photosensitive group outside of holiday time (P < 0·0001), but not when on a sunny holiday, as healthy people increased their sunscreen use at this time. Despite the reduced sun exposure, photosensitive subjects were no more likely to take vitamin D supplements than healthy subjects were; they also exhibited a significantly higher rate of unemployment (P < 0·05).

CONCLUSIONS

Photosensitivity disorders negatively influence lifestyle including employment status; more attention is required to the socioeconomic impact of these conditions.

Proficiency testing of 25-hydroxyvitamin D (25-OHD) assays

The Vitamin D External Quality Assessment Scheme (DEQAS) has been monitoring 25-OHD assay performance since 1989. The scheme has expanded rapidly in recent years and has 670 participants in 35 countries (July 2009). Five samples of human serum are distributed quarterly and the results analyzed to give an All-Laboratory Trimmed Mean (ALTM) and SD. Each participant has internet access to a preliminary report after submission of results and, following the results deadline, a final report is e-mailed to designated staff in each laboratory. The last 15 years has seen an improvement in mean inter-laboratory imprecision (CV), from 32.0% (1994) to 15.3% (2009) and most major methods are now giving results within plus or minus 7.4% of the ALTM (2009). DEQAS has regularly conducted and reported on a number of investigations into the performance of 25-OHD methods. A gas chromatography-mass spectrometry (GC-MS) reference method for 25-OHD is under development and will be used to assess whether the ALTM remains the most appropriate target for DEQAS samples.

Seasonal 25-hydroxyvitamin D changes in British postmenopausal women at 57 degrees N and 51 degrees N: a longitudinal study

The UK has insufficient intensity of sunlight at wavelengths 290-315 nm to enable cutaneous synthesis of vitamin D from October to April. There are regional differences in UVB strength throughout the UK but whether this translates to differences in vitamin D status is not known. We have reported seasonal variations in a cross-sectional study of over 3000 Scottish women in Aberdeen. The aim of this longitudinal study was to compare the seasonal variation of serum 25-hydroxyvitamin D [25(OH)D] in postmenopausal women residing in Aberdeen (57 degrees N) and Surrey (51 degrees N). Women attended 3-monthly visits over 12 months, starting summer 2006. In Aberdeen, 338 Caucasian women (mean age+/-SD, 61.7+/-1.5 years); and at Surrey, 138 Caucasian women (61.4+/-4.5 years) and 35 Asian women (59.9+/-6.4 years) had serum 25(OH)D measured by IDS enzyme immunoassay. In winter/spring none of the Caucasian women living in Surrey had 25(OH)D<20 nmol/L, but nearly a quarter of women in Aberdeen were vitamin D-deficient. This number decreased to 4.2% in summer/autumn. For the Asian women 17.1% were vitamin D-deficient in summer, increasing to 58.1% in winter. Using higher 25(OH)D deficiency cut-offs, the percentage of women affected was much higher. These longitudinal data show clear differences in vitamin D status between the north and south of the UK, and marked ethnic differences. They are consistent with our previous data and with cross-sectional data from the 1958 birth cohort. The low vitamin D status may have implications for bone health and other health outcomes, which is currently being investigated in this publication group. The extent of vitamin D deficiency in Asian women residing in the South of England is of concern.

Endovascular histologic effects of ultrathin gold- or vitronectin-coated platinum aneurysm coils in a rodent arterial occlusion model: a preliminary investigation

BACKGROUND AND PURPOSE

Novel stratagems to improve the efficacy of platinum coils in occluding cerebral aneurysms have primarily involved coating coils with materials thought likely to provoke more desirable histologic reactions. No investigations to date, however, have evaluated the utility of gold or vitronectin coatings, despite known endovascular histologic effects of these agents, which may be favorable for treating cerebral aneurysms. This study was conducted to evaluate the degree of endovascular histologic change associated with ultrathin gold- or vitronectin-coated platinum coils. It was hypothesized that such coatings would increase intra-aneurysmal intimal hyperplasia and the degree of luminal occlusion compared with standard platinum coils.

MATERIALS AND METHODS

The ligated carotid artery rat model was used to study 4 different aneurysm coil conditions: no coil (sham-surgery controls), uncoated platinum coil, and gold- or vitronectin-coated platinum coil. Two weeks postimplantation, the aneurysms were harvested and stained with hematoxylin-eosin. Slides were evaluated for the degree of neointimal response by a pathologist blinded to treatment. Additional quantitative evaluation was performed blindly by using the ratio of intimal-to-luminal cross-sectional area.

RESULTS

A gold- or vitronectin-coated platinum aneurysm coil produced a statistically significant increase in neointimal response compared with a sham (no coil). Arterial segments treated with gold-coated platinum coils also demonstrated a statistically significant 100% increase in neointimal response compared with those treated with bare platinum coils.

CONCLUSIONS

In concordance with our hypothesis, ultrathin coatings of gold provoked a neointimal response and degree of luminal occlusion greater than that of plain platinum aneurysm coils in a rat arterial occlusion model.

Vitamin D deficiency in children with renal disease

AIMS

The purpose of this study was to assess the vitamin D status of children with renal disease attending the outpatient clinics of our tertiary nephrology centre, allowing us to determine the prevalence of vitamin D deficiency and study its relationship with glomerular filtration rate (GFR) and serum parathyroid hormone (PTH) concentration.

METHODS

90 boys and 53 girls (99 white Caucasians, 38 of South Asian origin and six from other ethnic groups) were enrolled into the study. 18 were on dialysis (15 peritoneal dialysis and three haemodialysis), 61 had a functioning renal transplant (19 with reduced GFR), 18 had chronic renal failure and 46 had a variety of renal disorders with normal renal function. Serum/plasma concentrations of 25(OH)D, 1,25(OH)2D, PTH, creatinine, calcium, phosphate and alkaline phosphatase were measured. Patients with serum 25(OH)D concentrations of less than 25 nmol/l were considered to be deficient and those with levels of 25-50 nmol/l considered insufficient.

RESULTS

26% of all patients were 25(OH)D deficient and a further 32% were insufficient. The prevalence in South Asians was higher (87% deficient/insufficient) than in white Caucasians (46% deficient/insufficient, p<0.001). In children with reduced GFR who were not on dialysis, 25(OH)D levels of less than 50 nmol/l were associated with a high PTH in 90% of cases compared to only 50% of those with normal vitamin D concentrations (p = 0.013).

CONCLUSION

A high proportion of renal patients were vitamin D deficient/insufficient, particularly children of South Asian origin. High PTH values in the setting of reduced GFR might be due to vitamin D deficiency and should lead to estimation of serum 25(OH)D concentration.

Forearm bone geometry and mineral content in UK women of European and South-Asian origin

Ethnic variation in areal bone mineral density (BMD) has been well documented. Such variation may, however, reflects differences in bone geometry rather than volumetric BMD (vBMD). The aim of the study was to compare bone geometry, mineral content (BMC) and vBMD in two ethnic groups, and study the influence of body size, physical activity, reproductive variables, 25 hydroxy-vitamin D (25(OH)D) and parathormone (PTH) status on any observed differences. The data were from a population-based, cross-sectional survey of peak bone mass in South Asian and European women, the population consisted 230 pre-menopausal South Asian (n=118, mean age 28.6+/-4.6 years) and European (n=112, mean age 30+/-4.3 years) women of UK origin. Women who participated completed an interviewer assisted questionnaire, had blood taken for assessment of 25(OH)D and PTH and had measurements of their distal (4%) and diaphyseal (50%) radius geometry, BMC and vBMD using peripheral quantitative computed tomography. At the 50% radius, South Asians had lower vBMD (p<0.001), BMC (p<0.001), cortical area (p<0.001), cortical thickness (p<0.001), cross-sectional area (p=0.04) and increased medullary area (p<0.04). Cross-sectional muscle area and stress strain index, however, were not different. Adjustment for age, height and weight attenuated, the difference in cross-section area but did not account for any of the other observed differences. Further adjustment for reproductive variables a physical activity index, 25(OH)D and PTH, attenuated ethnic differences in cortical BMC, area and thickness which became non-significant; however, ethnic differences in cortical vBMD and medullary area persisted. At the 4% site, after adjusting for age, height and weight, there was no difference in total area, total or trabecular vBMD between ethnic groups. After further adjustment for physical activity, reproductive variables, 25(OH)D and PTH, trabecular vBMD was higher in the South Asians. In conclusion, there are differences in bone geometry, BMC and vBMD at the radial diaphysis between UK South Asians and Europeans which are not explained by differences in body size. Polar stress-strain index was similar, however, suggesting no important differences in bone strength.

Investigating sacroplasty: technical considerations and finite element analysis of polymethylmethacrylate infusion into cadaveric sacrum

BACKGROUND AND PURPOSE

Sacroplasty is not as routinely performed as vertebroplasty, possibly due to technical challenges and the paucity of data regarding subsequent outcomes. The first goal of the present investigation was to describe a technique for sacroplasty that facilitates safe needle placement and polymethylmethacrylate (PMMA) extrusion. The second goal was to perform finite element analysis (FEA) by using a geometric model of sacral fracture to identify mechanical outcomes of sacroplasty.

MATERIALS AND METHODS

Sacroplasty was performed on fresh pelvis specimens (n=4) under biplane fluoroscopy. Cadavers were imaged via CT before and after sacroplasty and volume rendered to examine needle placement and PMMA extrusion. The volume-rendered CT data were then used to generate geometric models of the intact, fractured, and cement-augmented fractured sacrum for comparison by using FEA.

RESULTS

CT data demonstrate that safe injection needle placement and PMMA delivery may be facilitated by orienting the needle parallel to the L5-S1 interspace and ipsilateral sacroiliac joint, then targeting the superolateral sacral ala within an area bounded by a line lateral to the posterior foraminal openings and a line superimposed on the medial edge of the sacroiliac joint. FEA revealed that simulated sacroplasty decreased maximal principal stress at the point of sacral fracture propagation by 83% and fracture gap micromotion by 48%.

CONCLUSION

Sacral landmarks can be used to place PMMA safely where sacral fractures occur. FEA suggests that sacroplasty may decrease fracture-associated mechanical stress and micromotion, which may contribute to patient reports of decreased pain and increased mobility postsacroplasty.

The anomalous behaviour of exogenous 25-hydroxyvitamin D in competitive binding assays

The Vitamin D International External Quality Assessment Scheme (DEQAS) was established in 1989 to monitor the performance of assays for 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (I,25(OH)(2)D). This is achieved through the quarterly distribution of five samples of human serum. Results are used to calculate an All-Laboratory Trimmed Mean and a Method Mean for each of the methods used by participants. In July 2005, participants were asked to assay serum to which 50.9 nmol of either 25-OHD(3) or 25-OHD(2) had been added as ethanolic solutions. The final concentration of ethanol in the serum was 0.7%. The distribution also included a sample of the original serum (OS) containing 0.7% pure ethanol. The percentage recoveries of exogenous 25-OHD(3) (R1) and 25-OHD(2) (R2) were calculated for each method. Results (OS nM, R1 and R2) were as follows: DiaSorin RIA (n=53); 39.2, 82.1%, 83.3%, DiaSorin Liason (n=16); 36.8, 81.4%, 88.6%, IDS RIA (n=21); 36.4, 54.2%, 29.1%, IDS OCTEIA (n=16); 47.3, 78.8%, 56.4%, Nichols Advantage (n=21); 58.9, 46.4%, 43.2%, HPLC (n=9); 42.6, 112.2%, 97.1%, LC-MS (n=4); 34.0, 111.5%, 118.1%. The IDS RIA and Nichols assays gave unexpectedly low recoveries. This does not appear to be a calibration problem or the effect of ethanol.

Sex hormone status may modulate rate of expansion of proximal femur diameter in older women alongside other skeletal regulators

CONTEXT

Little is known of associations between hip geometry and skeletal regulators. This is important because geometry is a determinant of both hip function and resistance to fracture.

OBJECTIVE

We aimed to determine the effects of sex hormone status and other candidate regulators on hip geometry and strength.

SUBJECTS AND METHODS

A random sample of 351 women aged 67-79 had two to four hip dual-energy x-ray absorptiometry scans performed over 8 yr of follow-up. Hip structural analysis software was used to measure subperiosteal diameter (PD) and the distance from the center of mass to the lateral cortical margin (d-lat) on three 5-mm-thick cross-sectional regions: narrow neck, intertrochanter, and shaft. Section modulus (Z), bone mineral density (grams per centimeter squared), and an index of bone mineral content (cross-sectional area) were calculated as estimators of bone strength. Serum analytes measured at baseline included SHBG, estradiol, PTH, creatinine, albumin, vitamin D metabolites, and glutamate- and gamma-carboxyglutamate-osteocalcin (OC). A linear mixed model was used to model associations with predictor variables, including testing whether the predictors significantly modified the effect of aging.

RESULTS

Aging was associated with increasing PD and d-lat, and higher baseline SHBG significantly modified this effect, in the case of PD, increasing the rates of change at the narrow neck region by 19% for SHBG level 2 sd higher than population mean (P = 0.026). Higher baseline creatinine was independently associated with faster increases in PD and d-lat with aging (P < 0.041). Z declined faster with aging if baseline PTH was higher, and higher albumin had a contrary effect. Z was positively associated with free estradiol and inversely associated with SHBG and glutamate-OC.

CONCLUSION

These results show large effects of SHBG on the regulation of proximal femur expansion and bending resistance, probably acting as a surrogate for low bioavailable estrogen. Potentially important effects for fracture resistance in old age were also revealed for PTH, markers related to renal function and the nutritional markers albumin and undercarboxylated OC.

Hypovitaminosis D among healthy adolescent girls attending an inner city school

AIMS

To determine the prevalence of hypovitaminosis D among healthy adolescent schoolgirls attending an inner city multiethnic girls' school.

METHODS

Fifty one (28%) of 182 girls (14 white, 37 non-white; median age 15.3 years, range 14.7-16.6) took part in the study. Biochemical parameters, dietary vitamin D intake, muscle function parameters, duration of daily sunlight exposure (SE), and percentage of body surface area exposed (%BSA) were measured.

RESULTS

Thirty seven (73%) girls were vitamin D deficient (25-hydroxyvitamin D (25OHD) <30 nmol/l) and 9 (17%) were severely deficient (25OHD <12.5 nmol/l). The median (range) 25OHD concentration of white girls (37.3 nmol/l (18.3-73.3)) was higher than that of non-white girls (14.8 nmol/l (5.8-42.8)). The median (range) concentration of parathyroid hormone in white girls (2.8 pmol/l (1.0-3.7)) was lower than that of non-white girls (3.4 pmol/l (1.7-34.2)). Serum Ca, inorganic phosphate, alkaline phosphatase, and 1,25-dihydroxyvitamin D were not different in white and non-white girls. For the whole group, 25OHD concentration was related to the estimated SE and %BSA, but not to estimated intake of vitamin D. In white girls, the estimated SE and %BSA were significantly higher than that of non-white girls. The median times taken to complete the Gower's manoeuvre and grip strength were not different in the two groups; these variables were not related to serum 25OHD.

CONCLUSIONS

Hypovitaminosis D is common among healthy adolescent girls; non-white girls are more severely deficient. Reduced sunshine exposure rather than diet explains the difference in vitamin D status of white and non-white girls.

Hypercalcaemia associated with granulomatous lymphadenitis and elevated 1,25 dihydroxyvitamin D concentration in a dog

A seven-year-old Labrador was presented with weight loss and mild generalised lymphadenopathy. Histopathology of an excised lymph node by the referring veterinarian demonstrated granulomatous lymphadenitis. At the time of referral, fine-needle aspirates of the lymph nodes confirmed the presence of ongoing granulomatous inflammation. Further investigations revealed marked hypercalcaemia, a low parathyroid hormone concentration, a parathyroid hormone related protein concentration within the reference range, and an elevated serum concentration of 1,25 dihydroxyvitamin D. An underlying cause of the granulomatous lymphadenitis could not be identified. The clinical signs, hypercalcaemia and elevated serum concentrations of 1,25 dihydroxyvitamin D resolved following prednisolone treatment. In contrast to dogs, hypercalcaemia occurred secondarily to granulomatous disease and elevated 1,25 dihydroxyvitamin D concentrations is a well-recognised condition in human beings. To the authors' knowledge, this is the first case report to describe elevated serum calcium and 1,25 dihydroxyvitamin D concentrations in a dog with histologically confirmed granulomatous disease.

Cyclic hydrostatic pressure and particles increase synthesis of 1,25-dihydroxyvitamin D3 by human macrophages in vitro

1,25-Dihydroxyvitamin D(3) has a pivotal role in bone resorption and osteoclast activity. As activated macrophages are known to synthesise 1,25-dihydroxyvitamin D(3), this study examined whether pressure modulated its synthesis. Pressure and particles have been shown to increase synthesis of pro-resorptive cytokines and other factors by cultured macrophages. Human peripheral blood macrophages were isolated, cultured and exposed to pressure (similar to that found in the human joint) and/or particles. Synthesis of 1,25-dihydroxyvitamin D(3) by macrophages was assayed using high pressure liquid chromatography and in situ hybridization. Synthesis of 1,25-dihydroxyvitamin D(3) but not 24,25-dihydroxyvitamin D(3) was increased in macrophages under pressure. In situ hybridization demonstrated an increase in 1alpha-hydroxylase expression in response to pressure or particles and simultaneous exposure to both stimuli generated higher expression of 1alpha-hydroxylase. In conclusion, this is the first study to demonstrate that mechanical loading, in the form of pressure, stimulates 1,25-dihydroxyvitamin D(3) synthesis in human macrophages. These findings have implications for the in vivo situation, as they suggest that 1,25-dihydroxyvitamin D(3) could be one factor stimulating osteoclastic bone resorption in pathologies, such as arthritis or implant loosening, where intra-articular or intra-osseous pressure is raised or where wear particles interact with macrophages.

Hypercalcaemia in two dogs caused by excessive dietary supplementation of vitamin D

A three-year-old Border collie was presented with a two-week history of lethargy, stiff gait, polydipsia and polyuria. Biochemical analysis revealed hypercalcaemia. Serum concentrations of 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) were markedly elevated and parathyroid hormone was undetectable. Subsequent analysis of the dog's diet revealed that the food contained excessive amounts of vitamin D. The hypercalcaemia resolved following treatment with bisphosphonates and dietary change. Hypervitaminosis D was diagnosed in a second unrelated dog, which had been fed the same brand of dog food as case 1. The dog was also hypercalcaemic and had markedly elevated serum concentrations of 25(OH)D and 1,25(OH)2D. Hypervitaminosis D in dogs has been reported to occur secondarily to ingestion of either rodenticides containing cholecalciferol or antipsoriatic ointments that contain vitamin D analogues. Hypervitaminosis D has also been reported following the treatment of hypoparathyroidism. To the authors' knowledge, this is the first report of hypervitaminosis D in dogs following the accidental over supplementation of a commercial diet with vitamin D. While the benefits of adequate dietary vitamin D are well established in dogs, the potential deleterious effects of over supplementation of vitamin D should also be acknowledged.

Hypocalcaemia associated with low serum vitamin D metabolite concentrations in two dogs with protein-losing enteropathies

Protein-losing enteropathies were diagnosed in two dogs that were initially presented with diarrhoea and weight loss. Plasma biochemistry in both cases revealed low concentrations of albumin, calcium and ionised calcium. Both dogs had an elevated plasma parathyroid hormone concentration and low serum 25-hydroxyvitamin D (25[OH]D) concentration. The first dog was diagnosed with lymphangiectasia on postmortem examination, and the second dog was diagnosed with chronic lymphocytic/ plasmacytic enteritis and severe cystic mucoid changes based on endoscopic duodenal biopsies. While a causal effect was not demonstrated, the protein-losing enteropathies may have caused reduced intestinal absorption of vitamin D leading to low plasma concentrations of ionised calcium and secondary hyperparathyroidism. To the authors' knowledge, this is the first report of low ionised calcium concentrations, low 25(OH)D and 1,25-dihydroxyvitamin D concentrations, and high parathyroid hormone concentrations in dogs with protein-losing enteropathies.

Compliance matching stent placement in the carotid artery of the swine promotes optimal blood flow and attenuates restenosis

OBJECTIVES

We assessed the value of a gradient-compliant stent in an animal model.

METHODS

Bilateral carotid arteries were stented with nitinol stents having variable-oversizing, variable-stiffness, and with (CMS, 10 animals) and without (SMART, four animals) compliance-matching endings. Angiography, hemodynamic, scanning-electron-microscopic and histological analyses were performed at 3-month. The protocol was completed in 14 among 19 swines.

RESULTS

Transient (1-month) exaggerated recoil, attributable to stress-induced phasic inhibition of vasorelaxation, developed at CMS endings. At mid-term, all stents were endothelialized; CMS-stents, but not SMART-stents, were incorporated into walls (one-strut-thickness). Restenosis developed outside SMART-stents (cell migration+wall-compensatory enlargement) whereas CMS-stents elicited no or focalized cell-accumulations at endings that bulged vascular walls radially outward. SMART-stents were blood-flow neutral, whereas CMS-stents favored (higher-stiffness, higher-oversizing) or opposed (lower-stiffness, less-oversizing) carotid blood flow.

CONCLUSIONS

Direct carotid stenting with stents having compliance-matched endings and specific requirements of stiffness and oversizing can optimize blood flow to the brain and restrict local restenosis.

The impact of atmospheric pollution on vitamin D status of infants and toddlers in Delhi, India

AIMS

To compare the vitamin D status of 34 children, 9-24 months old, living in an area of Delhi renowned for high levels of atmospheric pollution (Mori Gate), with a comparable age matched group of children from a less polluted (Gurgaon) area of the city.

METHODS

Serum concentrations of calcium, alkaline phosphatase (ALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured. Haze scores, regarded as a surrogate marker of solar UVB radiation reaching ground level, were measured in both areas.

RESULTS

Mean 25(OH)D of children in the Mori Gate area was 12.4 (7) ng/ml, compared with 27.1 (7) ng/ml in children living in the Gurgaon area (p < 0.001). The median ALP (p < 0.05) and mean PTH (p < 0.001) concentrations were higher in children living in the Mori Gate area than in the Gurgaon area. The mean haze score in the Mori Gate area (2.1 (0.5)) was significantly lower (p < 0.05) than in the Gurgaon area (2.7 (0.4)), indicating less solar UVB reaching the ground in Mori Gate.

CONCLUSION

We suggest that children living in areas of high atmospheric pollution are at risk of developing vitamin D deficiency rickets and should be offered vitamin D supplements.

Morphometry of the supra sciatic notch intrailiac implant anchor passage

STUDY DESIGN

Anatomic study of human ilia.

OBJECTIVE

To determine the anatomic dimensions influencing intrailiac anchor placement and design.

SUMMARY OF BACKGROUND DATA

The development of the Galveston intrailiac implant anchor markedly improved results of spinal instrumentation to the pelvis. Better quantification of the passage dimensions is needed for the design of anatomically specific implants.

METHODS

The length and outer diameter of two intrailiac anchor passages were determined from randomly selected, disease-free pairs of ilia from 129 white skeletons belonging to the Hamann-Todd Osteological Collection (Cleveland, OH, Museum of Natural History).

RESULTS

Path B, an anchor passage running from the posterior superior iliac spine to the anterior inferior iliac spine, was significantly longer than path A, proceeding from the posterior superior iliac spine to the superior rim of the acetabulum, in adult and teenage males and females. For example, in adult females path B measured 141.2 +/- 7.5 mm versus 124.9 +/- 7.1 mm, P = or < 0.0001. The absolute minimum path A length available for an intrailiac post or screw anchor, following the required posterior superior iliac spine removal, was 80 mm in adults and male teenagers and 70 mm in female teenagers. For path B the hip joint was not at risk, and a safe anchor passage of at least 90 mm in teenagers and 110 mm in adults was available. The minimum thickness of the paths occurred directly above the sciatic notch. It was significantly larger in path A than path B, 20.2 +/- 2.4 mm versus 14.4 +/- 3.2 mm, P < 0.0001.

CONCLUSION

Of the two supra sciatic intrailiac paths studied, the path passing from the posterior superior iliac spine toward the anterior inferior iliac spine provided a longer and potentially safer anchor site. These studies suggest techniques for accessing longer anchor paths and the need for larger diameter anchors in order to achieve optimum intra iliac anchor stiffness and strength.

Experimental and computational flow evaluation of coronary stents

Local flow alterations created by a metallic stent in a simulated coronary artery were studied to compare the hemodynamic effects of two different stent geometries. Dye injection flow visualization and computational fluid dynamics were used. Resting and exercise conditions were studied. Flow visualization using the dye injection method provided a qualitative picture of stent hemodynamics while the computational approach provided detailed quantitative information on the flow next to the vessel wall near the intersections of stent wires. Dye injection visualization revealed that more dye became entrapped between the wires where the wire spacing was smallest. The dye washout times were shorter under exercise conditions for both wire spacings tested. The computational results showed that stagnation zones were continuous from one wire to the next when the wire spacing was small. Results from greater wire spacing (more than six wire diameters) showed that the stagnation zones were separate for at least part of the cardiac cycle. The sizes of the stagnation zones were larger under exercise conditions, and the largest stagnation zones were observed distal to the stent. These studies demonstrate that stent geometry has a significant effect on local hemodynamics. The observation that fluid stagnation is continuous in stents with wire spacings of less than six wire diameters may provide a criterion for future stent design.

Altered calbindin mRNA expression and calcium regulating hormones in rat diabetic pregnancy

Offspring of rats with diabetes mellitus are at risk of reduced calcium and bone mineral content. Altered expression of the maternal calcium binding proteins, calbindin-D(9K) and calbindin-D(28K), which are involved in renal and placental calcium transport, may underlie these problems.We have investigated the effect of diabetes on circulating concentrations of regulatory hormones with respect to calbindin-D mRNA concentrations. Three rat groups were studied; control (CP), streptozotocin-induced diabetic (DP), and insulin-treated diabetic (DPI) pregnant rats. Calbindin-D(9K) and calbindin-D(28K) mRNA abundance in placenta and maternal kidney were measured at days 7, 15, 18 and 21 of gestation, together with serum or plasma concentrations of 1,25 dihydroxyvitamin D(3) (1, 25(OH)(2)D(3)), parathyroid hormone (PTH), PTH-related protein (PTHrP), calcitonin, oestradiol and IGF-I. An increase in placental calbindin-D(9K) mRNA abundance between days 18 and 21 in CP and DPI rats was severely blunted in the DP rats. In contrast, renal calbindin-D(28K) mRNA abundance was greater at days 7, 15 and 18 in DP compared with CP rats, as was calbindin-D(9K) at day 18. Calcitonin concentrations showed no differences between the groups, and both PTH and IGF-I were reduced over the first half of gestation, unlike the calbindins. In contrast, the concentrations of PTHrP and 1,25(OH)(2)D(3) were reduced at term in the DP group compared with the other two groups. Plasma oestradiol concentrations were lower in DP than in CP rats at days 7, 15 and 18, and most striking was the absence in DP rats of the peak of oestradiol seen at day 18 in CP rats. Despite the similarity between changes in placental calbindin mRNA and 1,25(OH)(2)D(3), previous work has shown placental calbindin-D(9K) regulation to be vitamin-D-independent. These studies produce suggestive evidence, therefore, that PTHrP and oestradiol may be involved in the altered calbindin-D expression by kidney and placenta in rat diabetic pregnancy.

Inherited predisposition to myasthenia gravis in Newfoundlands

Acquired myasthenia gravis was diagnosed in 6 Newfoundlands from 2 distinct lineages. Three dogs, including 1 pair of littermates, from each lineage were affected. History and clinical signs did not differ from that reported for other dogs with acquired myasthenia gravis. Although a genetic predisposition for development of certain autoimmune diseases in several species has been identified, the immunopathogenesis of myasthenia gravis is multifactorial and includes hormonal, environmental, and infectious disease factors. The high incidence of myasthenia gravis in these 2 distinct lineages of Newfoundlands, a breed with a low relative risk for development of this disease, suggests an underlying genetic mechanism. However, mode of inheritance could not be determined from this small number of dogs. Regardless, breeders should be alerted to this disorder, and they should consider removing Newfoundlands with acquired myasthenia gravis from breeding programs.

Novel mutations in the 1alpha-hydroxylase (P450c1) gene in three families with pseudovitamin D-deficiency rickets resulting in loss of functional enzyme activity in blood-derived macrophages

Pseudovitamin D-defiency rickets (PDDR) is an autosomal recessive disorder characterized by hypocalcemia, rickets (which are resistant to treatment with vitamin D), and low or undetectable serum levels of 1,25-dihydroxyvitamin D (1,25(OH)2D). The symptoms are corrected with 1,25(OH)2D treatment, and the disease is now believed to result from a defect in the cytochrome P450 component (P450c1; CYP27B1) of the renal 25-hydroxyvitamin D-1alpha-hydroxylase (1-OHase). We have studied genomic DNA from three families with PDDR and have identified the same homozygous mutation in the P450c1 gene in two of the index cases, causing a frameshift in exon 8, resulting in a premature stop codon in the heme-binding domain. The two cases in the third kindred were compound heterozygotes with missense mutations in exons 6 and 9. We have also identified a C/T polymorphism in intron 6 of the P450c1 genomic DNA. Interferon gamma-inducible 1-OHase activity in blood-derived macrophages was shown by 1,25(OH)2D synthesis in all control cells tested (37-184 fmol/h/106 cells) and those from the PDDR family parents (34-116 fmol/h/106 cells) but was totally absent from the patients' cells, indicating a defect in their macrophage 1-OHase, similar to the presumed renal defect. The assumption of similarity between the renal and macrophage P450c1 was supported by our ability to clone a 514 bp sequence, including the heme-binding region of the macrophage P450c1 cDNA from controls, which was identical to that published for both the renal and keratinocyte P450c1 cDNAs.

Ascorbic acid-induced chondrocyte terminal differentiation: the role of the extracellular matrix and 1,25-dihydroxyvitamin D

Chondrocyte terminal differentiation is associated with cellular hypertrophy increased activity of plasma membrane alkaline phosphatase and the synthesis of collagen type X. The hypertrophic phenotype of cultured chondrocytes can be stimulated by ascorbic acid but the underlying mechanisms for this phenotypic change are unclear. As ascorbic acid is central to many hydroxylation reactions, the possibility was examined that its pro-differentiating effects are mediated by its effects on collagen and vitamin D metabolite formation. In vitro studies indicated that ascorbic acid-induced chondrocyte alkaline phosphatase activity was inhibited by the addition of both collagen and proteoglycan synthesis inhibitors. The addition of arginine-glycine-aspartic acid (RGD)-containing peptides also resulted in lower alkaline phosphatase activity. Chicks supplemented with dietary ascorbic acid had higher concentrations of both collagen and proteoglycans within their growth plates but the chondrocyte maturation rate was unaltered. No evidence was obtained to suggest that ascorbic acid-induced collagen production was mediated by lipid peroxidation. In addition, supplementation with dietary ascorbic acid resulted in higher serum 1,25-dihydroxyvitamin D3 concentrations and increased chondrocyte vitamin D receptor number. Ascorbic acid-treated chondrocytes maintained in vitro also had increased vitamin D receptor numbers but chondrocyte receptor affinity for 1,25-dihydroxyvitamin D3 was unaltered. These results indicate that ascorbic acid promotes both chondrocyte matrix production and 1,25-dihydroxyvitamin D3 synthesis, accompanied by upregulation of the vitamin D receptor. Thus, ascorbic acid may be causing amplification of the vitamin D receptor-dependent genomic response to 1,25-dihydroxyvitamin D, resulting in promotion of terminal differentiation. Strong evidence is provided to support the hypothesis that ascorbic acid-induced chondrocyte terminal differentiation is mediated by interactions between integrins and RGD-containing cartilage matrix proteins.

Measurement of plasma 1,25 dihydroxyvitamin D using a novel immunoextraction technique and immunoassay with iodine labelled vitamin D tracer

We evaluated a novel assay for the measurement of 1,25 dihydroxyvitamin D (1,25 (OH)2D). Immunoextraction of 1,25(OH)2D is performed using a mini column containing a solid-phase monoclonal antibody followed by radioimmunoassay (RIA) using an 125I-labelled 1,25(OH)2D derivative tracer and Sac-cell separation. The mean recovery of 1,25(OH)2D3 was 101%, linearity was excellent, inter- and intra-assay coefficients of variation were 9, 8 and 13% and 11, 10 and 14% at low, medium and high concentrations of 1,25 (OH)2D3, respectively. The cross-reactivity of vitamin D metabolites was < 0.0015% for 25-hydroxyvitamin D3, 24, 25 dihydroxyvitamin D3 and dihydrotachysterol and 0.54% for 1 alpha calcidol. 1,25 dihydroxyvitamin D2 cross-reactivity was 79%. The detection limit of the assay was 5 pmol/L. Comparison with a commercial radio receptor assay (RRA) and an in-house RIA gave regression equations of y = 0.94x + 11.8 (r = 0.98) and y = 0.91x-1.7 (r = 0.95), respectively, with no major discrepancies between the methods in all patient groups studied. Plasma concentrations of 1,25(OH)2D obtained with the assay were as follows: normal, unsupplemented subjects: mean 88, range 48-155 pmol/L, n = 68, patients with chronic renal failure: mean 11, range 3-36 pmol/L, n = 27, primary hyperparathyroidism: mean 198, range 130-299 pmol/L, n = 23, Paget's disease: mean 92, range 42-149 pmol/L, n = 24, osteomalacia: mean 43, range 27-61 pmol/L, n = 9. A minimum sample volume of 300 microL is required, the hands-on time is significantly less than other commercial assays and the measuring procedure is gamma counting rather than scintillation counting. The assay offers several advantages over previous methods and should allow more laboratories to offer measurement of 1,25(OH)2D as part of their repertoire.

Increased catabolism of 25-hydroxyvitamin D in patients with partial gastrectomy and elevated 1,25-dihydroxyvitamin D levels. Implications for metabolic bone disease

Serum vitamin D metabolites and PTH were measured in seven subjects with a history of previous partial gastrectomy (PGX) and metabolic bone disease. The elimination t1/2 of [3H]25-hydroxyvitamin D3 ([3H]25OHD3) in serum was assessed after an iv pulse dose of 5 microCi [26,27-3H]25OHD3. Median serum 25OHD3 was 37.5 (27.5-101.3) nmol/L, [normal range (NR) 10.8-58.5 nmol/L], mean serum 1,25-dihydroxyvitamin D [1, 25-(OH)2D3] was raised at 175 +/- 72 pmol/L, (NR 48-120 pmol/L) and mean PTH was also high, 67 +/- 27 ng/L, (NR 10-60 ng/L). Serum t1/2 [3H]25OHD3 ranged from 10.9-21.2 days. A strong negative correlation existed between t1/2 [3H]25OHD3 and serum 1,25-(OH)2D3 [Spearman's rank correlation coefficient (r = -0.82, P = 0.002)] and PTH [Spearman's rank correlation coefficient (r = -0.81, P = 0.001)]. Four subjects who had high initial PTH concentrations (60-115 ng/L) and elevated 1,25-(OH)2D levels (162-300 pmol/L) were reassessed after calcium supplementation to suppress secondary hyperparathyroidism (2 degrees HPT). In this subgroup, after-treatment PTH fell from 82 +/- 24 to 52 +/- 24 ng/L (mean +/- SD), not significant; 1,25-(OH)2D fell from 210 +/- 61 to 116 +/- 28 pmol/L, P = 0.015; and t1/2 [3H]25OHD3 increased from 13.2 +/- 1.9 to 18.9 +/- 3.1 days, P = 0.012. Patients with PGX and evidence of 2 degrees HPT with elevated 1,25-(OH)2D have a reduced t1/2 [3H]25OHD3, and this may explain the increased susceptibility of the subjects to osteomalacia. Calcium supplementation suppresses 2 degrees HPT, increases t1/2 [3H]25OHD3 and may protect against PGX osteoporosis and osteomalacia.

Growth plate chondrocyte vitamin D receptor number and affinity are reduced in avian tibial dyschondroplastic lesions

Tibial dyschondroplasia (TD) is a condition of rapidly growing poultry in which a mass of unmineralized cartilage extends distally from the tibiotarsal growth plate, leading to deformity and lameness. The lesion is characterized by the accumulation of prehypertrophic chondrocytes, probably because the maturing chondrocytes are unable to differentiate fully. The condition can be prevented by feeding 1,25-(OH)2D3. We have investigated the possibility that vitamin D receptors (VDR), through which 1,25-(OH)2D3 exerts its differentiating effects on chondrocytes, may be defective in TD birds. Chondrocytes were isolated from the proliferating and hypertrophic zones of normal tibiotarsi and from the proliferating zone and lesion of affected birds and receptors were characterized by Scatchard analysis. Results showed that, while cells from the proliferating zone in TD birds had normal receptors, those from the TD lesion had significantly lower numbers and affinity for 1,25-(OH)2D3 compared to all other zones. Lesion VDR had low affinity; Kd 83.9 +/- 20.6 pM compared to 30.0 +/- 2.8, 37.8 +/- 3.1, and 33.0 +/- 4.0 pM (p < 0.001), and low receptor number per cell, 920 +/- 74, compared to 1329 +/- 151, 1664 +/- 167, and 1360 +/- 104 (p < 0.01) in the normal proliferating, normal hypertrophic, and TD proliferating cells, respectively. These findings were confirmed by immunohistochemical localization of VDR in sections of normal and TD growth plates using monoclonal antibody 9A7 gamma. In normal growth plate, most cells were VDR positive with intense staining in the mature hypertrophic chondrocytes; in TD growth plates, proliferating zone cells stained well but signal was largely absent from chondrocytes in the lesion. Image analysis showed integrated nuclear staining density per cell of 168.2 +/- 36.9 arbitrary units in normal hypertrophic cartilage compared to 98.8 +/- 60.2 units in the top of the lesion and 2.2 +/- 2.0 units in the midlesion. We conclude that both numbers and affinity of VDR are reduced in TD and this may explain the failure of chondrocytes to differentiate to the mature form. The adverse consequences of defective receptors may be partly overcome by treatment with 1,25-(OH)2D3.

Change in trabecular architecture as measured by fractal dimension

The objective of this work was to expose dried trabecular bone material to a decalcifying environment and to quantify the change in the spatial distribution of the bone with a fractal measure. Digitized radiographic images were produced from four separate slices of human vertebral bone as they dissolved within a solution of nitric acid. Pixel data from a region of interest (ROI) within the trabecular bone were used to estimate the time-dependent change in fractal dimension of the ROI as the bone dissolved. Results demonstrated that a change in the spatial distribution of trabecular material may be expressed in terms of a concurrently changing estimate of the fractal dimension.

A method to evaluate the elastic behavior of vascular stents

PURPOSE

To develop a simple method for determining the elastic behavior of vascular stents.

MATERIALS AND METHODS

An experimental apparatus was constructed to determine the elastic behavior of four different vascular stents. Each stent was expanded within an artificial compliant vessel and was subjected to an increasing external pressure. The cross-sectional area of each stent was recorded at incremental changes in pressure. Compliance was estimated from the slope of a linear regression analysis fit to the pressure-area data in the elastic range of deformation.

RESULTS

The self-expandable stents were the most compliant, and balloon-expandable stents exhibited the least compliance. The balloon- expandable stents initially deformed in an elastic manner and then yielded irrecoverably at higher pressures.

CONCLUSION

A simple method has been devised that allows the elastic behavior of stents to be assessed. Quantification of stent compliance with this method is important as a predictor of stent resistance to compression in vivo.