Effects of duration of treatment and dosage of eicosapentaenoic acid and stearidonic acid on red blood cell eicosapentaenoic acid content.

OBJECTIVE: The purpose of this randomized, controlled, parallel group study was to characterize the relationships between dosages of stearidonic acid (SDA) and eicosapentaenoic acid (EPA), and incorporation of EPA into red blood cell (RBC) membranes over time. METHODS: Healthy subjects (n=131) received capsules with placebo (safflower oil), SDA (0.43, 1.3, 2.6, or 5.2 g/d) or EPA (0.44, 1.3, or 2.7 g/d) for 12 weeks. RBC fatty acids were analyzed biweekly. RESULTS: RBC %EPA increased in all EPA and SDA groups (p<0.02 vs. control) except the 0.43 g/d SDA group (p=0.187). For theoretical intakes of EPA of 0.25, 0.5, and 0.89 g/d, the amounts of SDA needed to achieve equivalent RBC EPA enrichment were 0.61, 1.89, and 5.32 g/d (conversion efficiencies of 41%, 26%, and 17%), respectively. CONCLUSIONS: SDA increased RBC %EPA in a dosage and time-dependent manner at intakes as low as 1.3 g/d.

Psychoneuroimmunology and HIV-1.

Recent psychoneuroimmunologic findings have suggested that it may be useful to evaluate the influence of behavioral factors on immune functioning and disease progression among human immunodeficiency virus-Type 1 (HIV-1) infected individuals. Behavioral interventions with immunomodulatory capabilities may help restore competence and thereby arrest HIV-1 disease promotion at the earliest stages of the infectious continuum. Evidence describing benefits of behavioral interventions such as aerobic exercise training on both psychological and immunological functioning among high-risk HIV-1 seronegative and very early stage seropositive gay men is presented. The HIV-1 infection is cast as a chronic disease for which early immunomodulatory behavioral interventions may have important physical and psychological impact.

Hyperparathyroidism and hypotestosteronemia of acute renal failure.

Acute and chronic renal failure are associated with a marked reduction in the serum levels of testosterone. The mechanisms underlying this abnormality are unknown. Certain data have implicated the high blood levels of parathyroid hormone (PTH) of uremia in the genesis of the hypotestosteronemia. The effects of 3 days of acute uremia in dogs with intact parathyroid glands and in thyroparathyroidectomized animals on serum testosterone levels and on the calcium content of the hypothalamus, pituitary gland, and the testes were examined. Similar studies were performed in normal dogs treated with parathyroid extract for 3 days. The serum levels of testosterone were significantly (p less than 0.01) reduced, and the calcium levels of hypothalamus, pituitary gland, and testes were significantly (p less than 0.01) increased in the acutely uremic dogs with intact parathyroid glands and in the normal dogs treated with parathyroid extract. Prior parathyroidectomy in the acutely uremic dogs prevented these abnormalities. The results of our study assign an important role for the excess blood levels of PTH in uremia in the genesis of the hypotestosteronemia. The data suggest that the effect of excess PTH on serum testosterone levels may be mediated through the accumulation of calcium in the organs which participate in synthesis and/or release of testosterone.

Effects of long-term therapy with calcitriol in patients with moderate renal failure.

Since abnormalities in divalent ion metabolism occur early in renal insufficiency, treatment of patients with moderate renal failure with calcitriol could halt and/or reverse these disturbances. The effects of long-term treatment with calcitriol (0.5 microgram/day) in three such patients were evaluated. Serum calcium level rose from 0.3 to 0.7 mg/dL. Blood parathyroid hormone levels were mildly elevated and fell to normal. Intestinal absorption of calcium increased. The patients had hypocalciuria and the urinary calcium level increased. Creatinine clearance remained stable in all patients. Iliac crest biopsy specimens obtained after double tetracycline hydrochloride labeling revealed mild osteomalacia and hyperparathyroid bone disease that healed after therapy. The data show that a small dose of calcitriol is safe and effective for the management of the derangements of divalent ion metabolism in patients with moderate renal failure.

Reversal of skeletal resistance to parathyroid hormone in uremia by vitamin D metabolites: evidence for the requirement of 1,25(OH)2D3 and 24,25(OH)2D3.

This study evaluates the role of vitamin D metabolites in the genesis of the skeletal resistance to the calcemic action of PTH in uremia. The changes in serum calcium after infusion of 2 U of PTE per kilogram per hour for 8 hr were evaluated in thyroparathyroidectomized dogs before and after 1 and 3 days of acute uremia produced by bilateral nephrectomy. The animals received vitamin D metabolites during the 3 days of uremia. Supplementation of 0.68 microgram/day 1,25(OH)2D3 and 24R,25(OH)2D3 restored the calcemic response to PTE to normal. This is in contrast to only partial correction of the response to PTE by 1,25(OH)2D3 alone. Administration of 1.36 microgram/day 24R,25(OH)2D3 did not improve the calcemic response to PTE. The results indicate that (1) both 1,25(OH)2D3 and 24R,25(OH)2D3 are necessary for the complete reversal of the impaired calcemic response to PTE, (2) this effect is not due to the increase in the amount of the dihydroxylated compounds of vitamin D, since equivalent amounts of these compounds in the form of 24R,25(OH)2D3 alone had no effect, and (3) the better effect of the combination of 1,25(OH)2D3 and 24R,25(OH)2D3 is most probably due to an interaction between these two metabolites of vitamin D permitting an intact calcemic action of PTH.