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Calcium-based biomaterials have been intensively studied in the field of drug delivery owing to their excellent biocompatibility and biodegradability. Calcium-based materials can also deliver contrast agents, which can enhance real-time imaging and exert a Ca2+-interfering therapeutic effect. Based on these characteristics, amorphous calcium carbonate (ACC), as a brunch of calcium-based biomaterials, has the potential to become a widely used biomaterial. Highly functional ACC can be either discovered in natural organisms or obtained by chemical synthesis However, the standalone presence of ACC is unstable in vivo. Additives are required to be used as stabilizers or core-shell structures formed by permeable layers or lipids with modified molecules constructed to maintain the stability of ACC until the ACC carrier reaches its destination. ACC has high chemical instability and can produce biocompatible products when exposed to an acidic condition in vivo, such as Ca2+ with an immune-regulating ability and CO2 with an imaging-enhancing ability. Owing to these characteristics, ACC has been studied for self-sacrificing templates of carrier construction, targeted delivery of oncology drugs, immunomodulation, tumor imaging, tissue engineering, and calcium supplementation. Emphasis in this paper has been placed on the origin, structural features, and multiple applications of ACC. Meanwhile, ACC faces many challenges in clinical translation, and long-term basic research is required to overcome these challenges. We hope that this study will contribute to future innovative research on ACC.
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Objective:To explore the relationship between vitamin D status and diet, vitamin D and calcium supplements, and physical activity in children during the first five years of life.Methods:This was a large population-based cross-sectional multicenter study. Children aged 0-5 years were recruited from Children's Health Care Centers through stratified cluster random sampling in 10 cities in Jiangsu Province from April, 2014 to March, 2015. The food frequency method and the physical activity questionnaire were used to investigate the diet and physical activity respectively, and serum 25-hydroxyvitamin D (25-[OH]D) was detected via enzyme-linked immunosorbent assay.Results:A total of 5,289 children were investigated. Factors significantly associated with increased risk of vitamin D deficiency in children included milk consumption < 250 ml/d (odds ratio [OR] = 1.24), meat consumption > 150.0 g/d (OR = 1.46), preferences for meats (OR = 1.34), preferences for sweets (OR = 1.27), no vitamin D supplementation in the last 3 months (OR = 1.47), no calcium supplementation in the last 3 months (OR = 1.39), dose of vitamin D supplementation < 400 IU/d (OR = 1.19), time of sleeping < 10 h/d (OR = 1.38), and time of outdoor activity < 2 h/d (OR = 1.20). Children with these factors showed significantly lower 25-(OH)D levels by 4.43 nmol/L, 9.33 nmol/L, 7.10 nmol/L, 5.21 nmol/L, 8.76 nmol/L, 7.18 nmol/L, 5.40 nmol/L, 5.35 nmol/L, and 3.24 nmol/L respectively. The 25-(OH)D levels in children with breast feeding and preferences for vegetables were significantly lower by 2.46 nmol/L and 5.29 nmol/L, respectively. The 25-(OH)D levels in children with eggs consumption < 60.0 g/d and ≥ 60.0 g were 63.0 nmol/L and 69.0 nmol/L, respectively, showing statistically significant difference ( P = 0.026). Conclusions:Lower intake of milk and eggs, higher intake of meat, sweet foods, breast feeding, no vitamin D and calcium supplements, and less sleep and outdoor activity were associated with lower vitamin D levels in children during the first five years of life. This is an early study focused on the relationship between diet and vitamin D in children during the first five years of life.
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BACKGROUND: Calcium citrate has been used as calcium supplement, anticoagulant, anti-inflammatory agent and bone repair material in biomedical fields. OBJECTIVE: To describe the basic properties of calcium citrate, summarize and discuss the preparation process of calcium citrate and its main applications in biomedical field. METHODS: The research literature related to calcium citrate was searched on the Web of science, CNKI, Medline and other databases by computer. The main key words were “calcium citrate, bone repairing material, citrate and calcium phosphate” in English and “calcium citrate, bone repair materials” in Chinese. The searching time was from February 1920 to February 2020. RESULTS AND CONCLUSION: With the development and exploration of medical materials, it is necessary to change the original process to improve the biological activity of medical calcium citrate. It is an inevitable trend to obtain calcium citrate with various micro-morphology and high biological activity by controllable synthesis method. Calcium citrate is widely used as calcium supplement, anti-inflammatory agent, anticoagulant, bone repair material and other non-medical applications. Its advantages are being gradually explored by researchers. The preparation method plays a decisive role in the application field of calcium citrate. Different internal structure and size will bring different application fields, from the smallest chemical bond connection to the macroscopic morphology or mechanical properties. These factors may be the results of the dedicated exploration of researchers.
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Objective To investigate the effect of calcium supplementation during pregnancy on clinical symptoms,the incidence of gestational hypertension and childbirth labor. Methods A set of pregnant women in the same season and the same gestation age(20 weeks later) with the age of 20?35 years old in Maternal and Child Health Care Hospital of Haidian District of Beijing were selected as research subjects,according to its cal?cium circumstances,divided into calcium group with 220 cases,who took 600 mg calcium every day from 20 week of pregnancy to delivery,and control group with 192 cases who didn't supplement calcium or supplement calcium but not regular or amount was not up to standard. The serum calcium of 20 weeks and 36 weeks of pregnancy were measured,the incidence of calcium deficiency symptoms during pregnancy, the incidence of hypertension during pregnancy,the termination of pregnancy and the labor time were observed. Results The incidence of lumbar and sacral pain,gastrocnemius muscle spasm and calcium deficiency symptoms accompanied with diffi?culty walking of calcium group were 21. 4%( 47/220) ,6. 8%( 15/220) and 1. 4%( 3/220) ,significantly lower than the control group(53. 1%(102/192),20. 8%(40/192) and 4. 7%(9/192)),the differences were signifi?cant(χ2=44. 62,17. 40,3. 92;P0. 05) . Conclusion Cal?cium supplementation during pregnancy helps reduce system hypocalcemia symptoms, reduce the incidence of gestational hypertension,but have no effect on pregnancy outcome.
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Calcium intake has been insufficient in all age groups in previous Korean national surveys. This study was conducted to investigate calcium intake in Korean and American populations at different ages. We analyzed two national survey data: the 2007~2009 Korean National Health and Nutrition Examination Survey (KNHANES) and the 2007~2008 National Health and Nutrition Examination Survey (NHANES). Statistically, survey procedures were applied using the weight, cluster, and strata variables. The mean calcium intake of Koreans at ages of 1~2 y, 3~5 y, 6~11 y, 12~18 y, 19~64 y, and 65+y was lower than American populations at those ages. The sufficient proportions based on Korean Estimated Average Requirement (EAR) of 1~2 y, 3~5 y, 6~11 y, 12~18 y, 19~64 y, and 65+y in Koreans were 45.5%, 33.1%, 24.3%, 16.6%, 32.7%, and 19.0%. While the sufficient rates based on American EAR of 1~3 y, 4~8 y, 9~13 y, 14~18 y, 19~30 y, 31~50 y, 51~70 y, and 71+y in US population were 88.5%, 54.4%, 35.2%, 35.8%, 55.3%, 55.2%, 40.6%, and 24.5%. Overall, the major foods contributing to calcium intakes in Koreans were milk, baechukimchi, and anchovies, whereas, milk products, pasta, or bread were major contributions to calcium in American populations. The calcium supplement intakes in the American population were 5.5 mg (1~2 y), 15.5 mg (3~5 y), 13.9 mg (6~11 y), 35.7 mg (12~18 y), 150.3 mg (19~64 y) and 334.4 mg (> or =65 y). These results suggest that Korean adolescents and older adults are the most insufficient in dietary calcium intakes among Koreans. In order to accurately estimate calcium intakes in Korean populations, calcium supplements and calcium-fortified foods should be considered.
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Adolescent , Adult , Humans , Bread , Calcium , Calcium, Dietary , Ear , Milk , Nutrition SurveysABSTRACT
Calcium supplement is needed for Chinese people.Calcium antagonists are also used in China.Authors suggest that calcium owns dual direction effects like a double-edged sword.Based on the knowledge of calcium metabolism,the adverse drugs reactions of excessive calcium supplement and the harmful effects of cellular calcium overload are introduced.Scientific and efficient application of calcium agents and calcium antagonists is expected.
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80%)as a calcium supplement.Methods Weanling SD rats(21 days after birth,n=50)were fed with low calcium forage for 10 days,then were divided into 5 groups randomly with 10 rats in each group,half male and half female.GroupⅠwas control group fed on low calcium forage.GroupⅡ~Ⅲ were fed on low calcium with L-lactic acid calcium.Group Ⅳ~Ⅴ were fed on low calcium forage with ultramicro-mussel shell powder.The experiment period was 4 weeks.The indices were including the eventual weight and length of the rats,the calcium absorption rate of calcium supplement,the concentrations of serum calcium,serum phosphorus,bone calcium,skeletal muscle calcium,myocardial calcium,hemocyte calcium,liver calcium,kidney calcium and the activity of alkaline phosphatase were assessed.Results The effect of ultramicro-mussel shell powder group was similar to L-lactic acid calcium.Conclusion The ultramicro-mussel shell powder can be well absorbed and utilized,and it can be used as a calcium supplement.