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Background: While dietary intake is known to influence serum markers of chronic kidney disease–mineral and bone disorder (CKD-MBD), the effects of recent food and beverage intake, particularly phosphorus consumption on these serum markers (phosphate, calcium, and parathyroid hormone [PTH]), are unknown in hemodialysis patients. An understanding of these effects could have direct and important implications on the management of CKD-MBD. Objective: To determine whether serum phosphate, calcium, and PTH levels were higher in hemodialysis patients who had consumed dietary phosphorus within 1 hour prior to their routine dialysis-related blood work (non–phosphorus-fasted) compared with patients who did not (phosphorus-fasted). Design: Observational, cross-sectional study. Setting: Kingston Health Sciences Center—Kingston General Hospital Site and its affiliated satellite hemodialysis units. Patients: Two hundred fifty-four adult patients receiving outpatient hemodialysis treatment for end-stage kidney disease were recruited. Measurements: The main measurements for this study included an assessment of dietary phosphorus intake as well as serum phosphate, calcium, PTH, albumin, Kt/V, and urea reduction ratio. Methods: A direct patient interview was performed to assess dietary phosphorus intake within 1 hour prior to routine dialysis-related blood work. The Canadian Nutrient File was then used to estimate dietary phosphorus based on the specific foods and beverages (including portion sizes and brands where applicable) identified in the interview. Serum measures of phosphate, PTH, calcium, albumin, and dialysis adequacy (Kt/V and urea reduction ratio) were obtained from participants’ routine dialysis-related blood work. Results: Non–phosphorus-fasted participants had nonsignificantly higher serum PTH levels compared to phosphorus-fasted participants (61.2 ± 64.7 vs 47.9 ± 39.7, P = .05). Non–phosphorus-fasted participants with PTH levels at the Kidney Disease Improving Global Outcomes (KDIGO) “target” (between 15 and 60 pmol/L) had significantly higher serum phosphate levels relative to phosphorus-fasted participants (1.6 ± 0.3 vs 1.4 ± 0.4, P = .006). In non–phosphorus-fasted participants, there was a nonsignificant association between the number of items containing inorganic phosphate additives and higher levels of serum phosphate and lower levels of serum calcium. Limitations: Some limitations include the cross-sectional nature of this study, self-reporting biases and estimates (as opposed to direct measurements) related to the dietary assessment, and the use of single (and not serial) assessments of serum measures. Conclusions: Dietary phosphorus intake in close proximity to blood work may contribute to subtle alterations in some key serum CKD-MBD parameters in adult outpatient hemodialysis patients but may not meaningfully alter CKD-MBD management.

Abstract Context Dietary consumption of phosphate is increasing, and elevated serum phosphate is associated with increased cardiovascular disease (CVD) risk. Sex differences in phosphate homeostasis and response to changes in dietary phosphate intake, which are not captured by clinically measured analytes, may contribute to differences in CVD presentation and bone disease. Objective To assess sex differences in acute phosphate homeostasis in response to a single oral phosphate challenge. Design Cross-sectional. Setting General community. Participants 78 participants (40-76 years) with measured glomerular filtration rate >60 mL/min/1.73 m2 and no clinically diagnosed CVD and 14 young healthy adults. Main Outcome Measures To elucidate subtle alterations in phosphate homeostasis, we employ an acute challenge whereby the hormonal response, circulating mineral levels, and urinary excretion are assessed following an oral challenge of phosphate. Results Although both males and females had similar changes in circulating phosphate, calcium, and parathyroid hormone in response to the challenge, females excreted ∼1.9x more phosphate and ∼2.7x more calcium than males, despite not consuming calcium. These sex differences were recapitulated in healthy young adults. This excretion response did not correlate to age, serum phosphate, or estradiol levels. The females with greater excretion of phosphate had higher levels of bone resorption markers compared to formation markers. Conclusions Taken together, these data identify sex differences in acute phosphate homeostasis, specifically that females may mobilize and excrete endogenous sources of calcium and phosphate in response to oral phosphate compared to males. While high levels of dietary phosphate negatively impact bone, our results suggest that females may incur more risk from these diets.

Diets containing inorganic phosphate additives are unbalanced with respect to calcium and these diets have been linked to the development of altered bone metabolism. Using 2 randomized cross-over studies in healthy humans, we (1) characterized the hormonal and urinary response to 2 meals with the same reported phosphorus amount (562–572 mg), where one was manufactured with inorganic phosphate additives and a comparatively lower Ca:P molar ratio (0.26 vs 0.48), and (2) assessed how acute homeostatic mechanisms adapt following 5-d exposure to recommended dietary phosphorus amount (~700 mg P/d) compared to a diet enriched with inorganic phosphate additives (~1100 mg P/d). Participants were then challenged with 500 mg of oral phosphorus in the form of inorganic phosphate after an overnight fast following each diet condition. Measurements included serum calcium, phosphate, PTH, and fibroblast growth factor 23 , vitamin D metabolites, and urine calcium and phosphate excretion. Following the meal containing inorganic phosphate additives with a low Ca:P ratio, serum phosphate was higher and more phosphate was excreted in the urine compared to the low additive meal. Although the Ca:P and calcium content was lower in the high additive meal, the same amount of calcium was excreted into the urine. Subsequently, increasing only dietary phosphate through additives resulted in lower 24-h excretion of calcium. The oral phosphate challenge promoted urinary calcium excretion, despite no consumption of calcium, which was attenuated when pre-acclimated to a high phosphate diet. These data suggest that ingestion of inorganic phosphate promotes calcium excretion, but homeostatic mechanisms may exist to reduce calcium excretion that are responsive to dietary intake of phosphate. Future studies are required to evaluate potential implication of diets enriched with inorganic phosphate additives on bone health. Lay Summary Excessive dietary phosphorus has been linked to the development of bone and vascular disorders. Further, highly bioavailable inorganic phosphate additives, which are unregulated, have been estimated to comprise approximately 50% of an individual’s consumed dietary phosphorus. Using 2 randomized cross-over studies in young healthy participants, we assessed (1) the hormonal and urinary response to 2 meals with the same reported phosphate amount, but one manufactured with inorganic phosphate additives, and (2) how acute homeostatic mechanisms adapt following 5-d of a diet supplemented with inorganic phosphate additives. The results suggest that ingestion of meals containing phosphate additives promotes excess calcium excretion, but homeostatic mechanisms in young healthy adults are sufficient to reduce calcium excretion in response to a 5-d dietary intake of these phosphate additives. These findings indicate an important role of inorganic phosphate additives on acute and chronic calcium homeostasis that will need to be carefully explored for potential implications on bone and/or vascular outcomes. Together these findings also indicate the critical importance of bioavailability of phosphate and the balance with calcium in dietary management. Graphical Abstract Graphical Abstract

[George Ivany] told the dean of arts and science that 10 faculty positions have to be cut from his college. He went on to say that the departments of English and history must be protected from these cuts because they are \"areas of excellence.\"

Shellfish growers routinely observe fish and invertebrates interacting with their aquaculture gear. To quantitatively assess these interactions, underwater action cameras (GoPro®) were used to document fish and invertebrate activity in and around floating oyster bags, cages, and a natural marsh habitat on an oyster farm in the Little Egg Harbor region of Barnegat Bay, New Jersey, USA, in 2018. A free and open-source event-logging software was used to analyze video files. A total of 21 species from 4 phyla were identified across all days and sites. Nekton were quantified from continuously recorded video using the MaxN abundance metric, defined as the maximum number of individuals of a given species present within each 1 min segment of video. Species of both ecological and economic importance in the local ecosystem used the 3 intertidal habitats. Abundance and community composition observed around oyster cages differed from that around floating oyster bags and marsh edge; the latter 2 habitats were not significantly different. Juvenile fish were frequently observed, suggesting that the oyster farm may provide similar natural history functions as other natural marsh habitat.