Effect of minor amounts of β-calcium pyrophosphate and hydroxyapatite on the physico-chemical properties and osteoclastic resorption of β-tricalcium phosphate cylinders

β-Tricalcium Phosphate (β-TCP), one of the most used bone graft substitutes, may contain up to 5 wt% foreign phase according to standards. Typical foreign phases include β-calcium pyrophosphate (β-CPP) and hydroxyapatite (HA). Currently, the effect of small amounts of impurities on β-TCP resorption is unknown. This is surprising since pyrophosphate is a very potent osteoclast inhibitor. The main aim of this study was to assess the effect of small β-CPP fractions (<1 wt%) on the in vitro osteoclastic resorption of β-TCP. A minor aim was to examine the effect of β-CPP and HA impurities on the physico-chemical properties of β-TCP powders and sintered cylinders. Twenty-six batches of β-TCP powder were produced with a Ca/P molar ratio varying between 1.440 and 1.550. Fifteen were further processed to obtain dense and polished β-TCP cylinders. Finally, six of them, with a Ca/P molar ratio varying between 1.496 (1 wt% β-CPP) and 1.502 (1 wt% HA), were incubated in the presence of osteoclasts. Resorption was quantified by white-light interferometry. Osteoclastic resorption was significantly inhibited by β-CPP fraction in a linear manner. The presence of 1% β-CPP reduced β-TCP resorption by 40%, which underlines the importance of controlling β-CPP content when assessing β-TCP biological performance.

Low in vitro third-body wear on total hip prostheses induced by calcium sulphate used for local antibiotic therapy

In case of implant associated infection, implant preservation is associated with high failure rates. Therefore, a removal or exchange of the implant is most often mandatory for treatment success. Alternatively, under certain conditions, local antibiotic delivery can be applied - preserving the implant, using for example calcium sulphate as a resorbable carrier. In this work, third-body wear on total hip prostheses caused by calcium sulphate particles was tested in a hip simulator. Inlays made of ultra-high-molecular-weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) against 28 mm CoCrMo heads and 36 mm alumina pairings were tested in triplicate, both with and without calcium sulphate particles in the test liquid. Neither the alumina articulations nor the CoCrMo heads were affected by the calcium sulphate particles since calcium sulphate is a relatively soft material. The polyethylene inlays showed 39-89 % higher wear during exposure compared to references, but wear returned to normal when no more particles were added. Thus, calcium sulphate might be used as antibiotic carrier even in the presence of total hip prostheses without fearing excessive third-body wear.

The association between chewing and swallowing difficulties and nutritional status in older adults

BACKGROUND

The aim of this study was to investigate the associations of chewing and swallowing dysfunctions to nutritional status in older adults.

METHODS

This cross-sectional study comprised a convenience sample of 1065 community-dwelling older adults living in rural United States. Dietary assessment included the Block Full Length Food Frequency Questionnaire, 24-hour Food Intake Recall and Mini Nutritional Assessment. Classification of chewing and swallowing difficulties was determined by a criterion of outlined factors.

RESULTS

In our sample, 113 (11%) had chewing difficulties, 51 (5%) had swallowing difficulties, and 11 (1%) had both. Compared to the Dietary Reference Intakes (DRIs), the study population was deficient in calories and several nutrients. Mean daily intake in individuals reporting chewing, swallowing, or difficulties with both were 1489 ± 360, 1461 ± 374 and 1374 ± 240 calories respectively. There was no statistically significant difference between the groups. Vitamin A, vitamin E and manganese were significantly lower in those with chewing difficulties while vitamin E and magnesium were significantly lower in individuals with swallowing difficulties (p < 0.05).

CONCLUSIONS

These results emphasize the importance of chewing and swallowing difficulties in modulating nutritional outcomes in older adults. These co-morbidities should be monitored in this population and intake of nutrient dense foods should be increased in those at risk.

The relationship of feeding patterns and obesity in dogs

The rates of dog obesity are increasing and a greater understanding of feeding patterns is required to combat the problem. This study examined relationships between dietary patterns and caloric intake, and nutrient content of foods fed as it relates to obesity in dogs in the United States. Sixty-one owners and their dogs were enrolled, and lifestyle surveys, food frequencies, and 3-day food records were collected. Significant differences in overall kcal intake per kilogram of body weight were found (p< 0.04). Crude fibre in dog food was positively associated with protein and negatively associated with fat regardless of the dog's weight (p< 0.001). Lean dogs received significantly more crude fibre in relation to overweight dogs regardless of the number of treats they received (p< 0.01), and their diets had greater micronutrient densities (p< 0.03) suggesting that high fibre influences body condition. Additionally, owners who ate nutrient-rich, calorie-poor diets had normal weight dogs, and owners that fed more table scraps had overweight dogs. Regardless of body condition, 59% of dogs received table scraps, which constituted 21% of daily caloric intake. The nutrient density of scraps fed was variable and did not meet National Research Council's recommendations for micronutrient adequacy.