Recovery of phosphorus from dairy manure: a pilot-scale study.

Phosphorus was recovered from dairy manure via a microwave-enhanced advanced oxidation process (MW/H2O2-AOP) followed by struvite crystallization in a pilot-scale continuous flow operation. Soluble phosphorus in dairy manure increased by over 50% after the MW/H2O2-AOP, and the settleability of suspended solids was greatly improved. More than 50% of clear supernatant was obtained after microwave treatment, and the maximum volume of supernatant was obtained at a hydrogen peroxide dosage of 0.3% and pH 3.5. By adding oxalic acid into the supernatant, about 90% of calcium was removed, while more than 90% of magnesium was retained. As a result, the resulting solution was well suited for struvite crystallization. Nearly 95% of phosphorus in the treated supernatant was removed and recovered as struvite.

In vivo Drosophilia genetic model for calcium oxalate nephrolithiasis.

Nephrolithiasis is a major public health problem with a complex and varied etiology. Most stones are composed of calcium oxalate (CaOx), with dietary excess a risk factor. Because of complexity of mammalian system, the details of stone formation remain to be understood. Here we have developed a nephrolithiasis model using the genetic model Drosophila melanogaster, which has a simple, transparent kidney tubule. Drosophilia reliably develops CaOx stones upon dietary oxalate supplementation, and the nucleation and growth of microliths can be viewed in real time. The Slc26 anion transporter dPrestin (Slc26a5/6) is strongly expressed in Drosophilia kidney, and biophysical analysis shows that it is a potent oxalate transporter. When dPrestin is knocked down by RNAi in fly kidney, formation of microliths is reduced, identifying dPrestin as a key player in oxalate excretion. CaOx stone formation is an ancient conserved process across >400 My of divergent evolution (fly and human), and from this study we can conclude that the fly is a good genetic model of nephrolithiasis.

Vitamin D and the kidney.

The kidney is essential for the maintenance of normal calcium and phosphorus homeostasis. Calcium and inorganic phosphorus are filtered at the glomerulus, and are reabsorbed from tubular segments by transporters and channels which are regulated by 1α,25-dihydroxyvitamin (1α,25(OH)(2)D) and parathyroid hormone (PTH). The kidney is the major site of the synthesis of 1α,25(OH)(2)D under physiologic conditions, and is one of the sites of 24,25-dihydroxyvitamin D (24,25(OH)(2)D) synthesis. The activity of the 25(OH)D-1α-hydroxylase, the mixed function oxidase responsible for the synthesis of 1α,25(OH)(2)D, is regulated by PTH, 1α,25(OH)(2)D, fibroblast growth factor 23 (FGF23), inorganic phosphorus and other growth factors. Additionally, the vitamin D receptor which binds to, and mediates the activity of 1α,25(OH)(2)D, is widely distributed in the kidney. Thus, the kidney, by regulating multiple transport and synthetic processes is indispensible in the maintenance of mineral homeostasis in physiological states.

Ingestion of a dietary supplement containing dehydroepiandrosterone (DHEA) and androstenedione has minimal effect on immune function in middle-aged men.

OBJECTIVE: This study investigated the effects of four weeks of intake of a supplement containing dehydroepiandrosterone (DHEA), androstenedione and herbal extracts on immune function in middle-aged men. DESIGN: Subjects consumed either an oral placebo or an oral supplement for four weeks. The supplement contained a total daily dose of 150 mg DHEA, 300 mg androstenedione, 750 mg Tribulus terrestris, 625 mg chrysin, 300 mg indole-3-carbinol and 540 mg saw palmetto. MEASUREMENTS: Peripheral blood mononuclear cells were used to assess phytohemagglutinin(PHA)-induced lymphocyte proliferation and cytokine production. The cytokines measured were interleukin (IL)-2, IL-4, IL-10, IL-1beta, and interferon (IFN)-gamma. Serum free testosterone, androstenedione, estradiol, dihydrotestosterone (DHT) were also measured. RESULTS: The supplement significantly increased serum levels of androstenedione, free testosterone, estradiol and DHT during week 1 to week 4. Supplement intake did not affect LPS or ConA proliferation and had minimal effect on PHA-induced proliferation. LPS-induced production of IL-1beta, and PHA-induced IL-2, IL-4, IL-10, or IFN-gamma production was not altered by the supplement. The addition of the same supplement, DHEA or androstenedione alone to lymphocyte cultures in vitro did not alter lymphocyte proliferation, IL-2, IL-10, or IFN-gamma, but did increase IL-4. In addition, serum HDL-C concentration significantly declined. CONCLUSION: These findings suggest that, although chronic intake of a complex dietary supplement containing DHEA, androstenedione and herbal extracts increases serum androgen levels, it has minimal effect on immune function in middle-aged men.