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Item Pathogenicity assessment of seven RYR1 variants in patients with confirmed susceptibility to malignant hyperthermia in the Netherlands.(Elsevier Ltd on behalf of British Journal of Anaesthesia, 2025-01-30) van den Bersselaar LR; Schiemann AH; Yang C-Y; Voermans NC; Malagon I; Scheffer G-J; Bjorksten AR; Gillies R; Hellblom A; Kamsteeg E-J; Snoeck MMJ; Stowell KM; Hemmings HCBackground Malignant hyperthermia (MH) susceptibility is associated with variants in RYR1, the gene encoding the skeletal muscle ryanodine receptor-1 (RyR1), in 70–75% of patients. Functional characterisation demonstrating an increased sensitivity to RyR1 agonists is necessary among other criteria for inclusion in the European Malignant Hyperthermia Group list of MH susceptibility diagnostic variants. Methods Seven variants in the RYR1 gene, p.Glu342Lys, p.Leu2288Ser, p.Phe2340Leu, p.Arg2676Trp, p.Val3324Ala, p.Phe4076Leu, and p.Trp5020Cys, identified in MH-susceptible individuals were introduced into the cDNA for the human RYR1 gene. These variants were tested in cultured human embryonic kidney HEK293 cells for their effect on calcium release in response to the RyR1 agonist 4-chloro-m-cresol. Calcium release of each variant was compared with wild-type and benign and pathogenic controls. Each variant was subjected to curation using the European Malignant Hyperthermia Group scoring matrix and ClinGen RYR1 Variant Curation Expert Panel guidelines. Results Six of seven RYR1 variants (p.Glu342Lys, p.Leu2288Ser, p.Phe2340Leu, p.Arg2676Trp, p.Val3324Ala, p.Phe4076Leu) showed hypersensitivity to 4-chloro-m-cresol compared with wild-type. The p.Trp5020Cys variant did not release calcium in response to 4-chloro-m-cresol. All variants had minor allele frequencies <0.1%. Rare exome variant ensemble learner scores of p.Glu342Lys, p.Leu2288Ser, p.Phe4076Leu, and p.Trp5020Cys were >0.85, supporting pathogenicity. Conclusions The variants p.Glu342Lys, p.Leu2288Ser p.Phe2340Leu, and p.Arg2676Trp are pathogenic or likely pathogenic for MH and can be used for presymptomatic testing for MH susceptibility. As current knowledge on the p.Val3324Ala, p.Phe4076Leu, and p.Trp5020Cys variants remains insufficient, they are still classified as variants of uncertain significance.Item Bone Health in Premenopausal Women with Coeliac Disease: An Observational Study.(MDPI (Basel, Switzerland), 2024-07-09) Schraders K; Coad J; Kruger M; Iacone RLow bone mineral density (BMD) is common in adults with coeliac disease (CD), even in individuals adhering to a gluten-free diet (GFD). Women are more likely to have low BMD and have an increased risk of osteoporosis, so women with pre-existing low BMD related to CD are at an even higher risk. BMD assessed by dual X-ray absorptiometry (DXA) and bone quality assessed through quantitative ultrasound (QUS) were investigated in 31 premenopausal women with CD consuming a GFD, and 39 matched healthy controls from the Lower North Island, New Zealand. In addition, bone metabolism and nutrient status were assessed, and four-day diet diaries were used to estimate nutrient intake. No statistically significant differences were found in BMD assessed by DXA between the two groups at the hip, lumbar spine or forearm. However, the parameters measured by the QUS were significantly lower in CD participants. Dietary data indicated significantly lower intakes of energy, dietary fibre, magnesium and phosphorus in women with CD, likely as a result of a reduced intake of wholegrain foods, and suggested that both groups had inadequate intake of calcium. No significant differences were demonstrated in biochemical parameters. BMD and bone biomarkers indicated no differences between coeliac and healthy women in New Zealand. However, these findings suggest that QUS may be more sensitive for the coeliac population, due to the disease's affect on the trabecular bone, and warrant further research.Item Calcium Nutrition of Broilers: Current Perspectives and Challenges(MDPI (Basel, Switzerland), 2023-05-09) David LS; Anwar MN; Abdollahi MR; Bedford MR; Ravindran V; Tufarelli VCalcium (Ca) plays an essential role in poultry nutrition as 99% of Ca is located in birds' skeletal system. However, oversupply of Ca rather than deficiency of Ca is the current concern in commercial broiler diets. Calcium is an inexpensive dietary nutrient due to the cheap and abundant availability of limestone, the major Ca source; therefore, little attention was given to the oversupply of Ca in the past. The recent shift in the use of digestible P in broiler feed formulations has necessitated a closer look at digestible Ca, as Ca and P are interrelated in their absorption and postabsorptive utilisation. In this context, data on ileal digestibility of Ca and P in ingredients has been determined. Preliminary data on the digestible Ca and digestible P requirements for the different growth stages of broilers have also recently become available. The present review focusses on these recent advances in Ca nutrition. In addition, aspects of homeostatic control mechanisms, different Ca sources and factors influencing Ca digestibility in poultry are covered.Item Seasonal Variations in the Composition and Physicochemical Characteristics of Sheep and Goat Milks(MDPI (Basel, Switzerland), 2022-06-14) Li S; Delger M; Dave A; Singh H; Ye A; Visioli FThere has been growing consumer interest in sheep and goat milk products as alternatives to cow milk products. The physicochemical characteristics of milk vary not only between ruminant species, but also during different seasons; they determine the nutritional quality and processing properties of the milk. In this study, we characterized sheep and goat milks from New Zealand over the seasons for their composition (macronutrients, macro- and micro-minerals, fatty acids, and proteins) and physicochemical properties (e.g., ionic calcium, fat globule size, casein micelle size, viscosity, and melting behavior of milk fat). Heat-induced (95 °C for 5 min) protein interactions and changes in the physical properties of the milks were also investigated. The compositional and structural features of sheep and goat milks were identified and compared with those reported for cow milk. Seasonal variations in the milk characteristics were more pronounced for sheep milk than goat milk and were probably affected by the production systems. Sheep milk, particularly in the late season, had the largest heat-induced increases in casein micelle size and viscosity, probably arising from the greater casein-whey protein and casein-casein interactions during heat treatment. This study provides comprehensive information on the properties of sheep and goat milks and highlights the interaction effects between species, season, and processing.Item Bone density and dietary calcium in New Zealand vegans : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand(Massey University, 2024) Clark, AbrilThe restrictive aspect of a vegan dietary pattern warrants attention, as it may lead to individuals unknowingly obtaining low intakes of calcium. Moreover, several international studies have reported low calcium intakes in vegans. Furthermore, prolonged low calcium intakes can result in reduced bone mineral density (BMD) and increased risk of developing osteoporosis later in life. In older adults, a calcium deficiency will exacerbate bone loss as ageing is associated with a decline in BMD. Moreover, pregnant women are at increased risk of developing a calcium deficiency due to the increased demands of calcium that is required for the growth of foetal bone. The evidence of a vegan diet impacting BMD have been inconclusive in the literature, therefore further research is required to understand bone health of vegans. Especially, in the context of NZ vegan adults as the measurement of bone parameters and calcium intakes have not been investigated in this population. Objectives: To describe calcium intake and bone health of NZ adults following a vegan diet. Methods: This cross-sectional study included adults (N=212) (>18yrs), who followed a vegan diet for more than 2 years. Demographic and lifestyle information was obtained from questionnaires. A 4-day food record was completed for analysis of calcium, zinc, protein, magnesium, phosphorus and vitamin C intake and compared to the Estimated Average Requirement (EAR). Weight, height and BMI were obtained, BMD was measured at the hip and spine using dual x-ray absorptiometry (DXA) and reported as Z-scores. Participants were categorised based on BMD Z scores stratified as follows: low BMD (for age and sex) <-2.0 and normal BMD >-2.0. Blood samples were taken for PTH, 25(OH)D and plasma calcium concentrations were corrected for albumin. All values are presented as mean and standard deviation. Differences in bone parameters between BMD groups were analysed using multiple T-tests. A linear regression analysis examined the association between calcium intake, corrected calcium concentrations, serum PTH levels, BMI, and physical activity levels and BMD Z scores at the lumbar spine and femoral neck. Results: Overall, Z scores at the lumbar spine and femoral neck were -0.29 ± 1.12 and -0.24 ± 0.89), respectively. Corrected calcium concentrations were 2.21 ± 0.33 mmol/L. Overall, calcium intake was 917 ± 347.23 (range 195 to 2,429 mg/day). The main source of calcium in the vegan diet was tofu and plant-based milks. The intake of protein (77 ± 27.80) g/day, magnesium (569 ± 181.05) mg/day, and vitamin C (145 ± 96.94) mg/day met the EAR, excluding vitamin and mineral supplements. However, the intake of phosphorus (1,472 ± 459.98) mg/day and zinc (10.6 ± 4.01) mg/day were below the EAR. Only BMI significantly predicted BMD Z-scores at the lumber spine (P = 0.004) and femoral neck (P = 0.003). Conclusion: The study found that most vegans had normal BMD for their age and sex, adequate calcium intakes and bone homeostasis markers. Despite mean intake of calcium exceeding the EAR, very low intakes demonstrated significant variations between participants. Tofu was identified as the main plant-based source of calcium amongst participants. Moreover, longitudinal research is required to understand the long-term impact of a vegan diet on bone health.Item Factors Associated with Bone Mineral Density and Bone Resorption Markers in Postmenopausal HIV-Infected Women on Antiretroviral Therapy: A Prospective Cohort Study(MDPI (Basel, Switzerland), 2021-06-18) Ellis C; Kruger HS; Viljoen M; Dave JA; Kruger MC; Weaver CThe study aimed to determine factors associated with changes in bone mineral density (BMD) and bone resorption markers over two years in black postmenopausal women living with human immunodeficiency virus (HIV) on antiretroviral therapy (ART). Women (n = 120) aged > 45 years were recruited from Potchefstroom, South Africa. Total lumbar spine and left femoral neck (LFN) BMD were measured with dual energy X-ray absorptiometry. Fasting serum C-Telopeptide of Type I collagen (CTx), vitamin D and parathyroid hormone were measured. Vitamin D insufficiency levels increased from 23% at baseline to 39% at follow up. In mixed linear models serum CTx showed no change from baseline to end (p = 0.363, effect size = 0.09). Total and LFN BMD increased significantly over two years, but effect sizes were small. No significant change in spine BMD over time was detected (p = 0.19, effect size = 0.02). Age was significantly positively associated with CTx over time, and negatively with total and LFN BMD. Physical activity (PA) was positively associated with LFN BMD (p = 0.008). Despite a decrease in serum vitamin D, BMD and CTx showed small or no changes over 2 years. Future studies should investigate PA interventions to maintain BMD in women living with HIV.