Manuscript peer review--a guide for health care professionals.

Peer review, in which peer experts assess the value of a manuscript submitted to a professional journal, is regarded as a crucial step in publication. It is generally agreed that its usefulness is highly dependent on the preparedness of each reviewer and quality of each assessment. With sustained growth in biomedical publications, more and more health professionals are being called on to serve as peer reviewers. An instructional framework should assist pharmacists and other health care professionals in conducting high-quality manuscript reviews.

Metabolic responses of postmenopausal women to supplemental dietary boron and aluminum during usual and low magnesium intake: boron, calcium, and magnesium absorption and retention and blood mineral concentrations.

Findings from animal studies indicate that dietary boron affects several aspects of mineral metabolism, especially when animals are subjected to nutritional stressors. Eleven postmenopausal volunteers living on a metabolic ward for 167 d (one 23-d equilibration period and six 24-d treatment periods) were fed a conventional basal diet that supplied a daily average intake of 0.36 mg B, 109 mg Mg, and < 0.10 mg A1/8400 kJ. They were given supplements of 0 (BB) or 3 mg B (SB, last two periods only), 0 (BMg) or 200 mg Mg (SMg) (with magnesium supplements held constant during the last two periods), or 0 (BAl) or 1000 mg A1 (SAl)/d. The SB treatment, compared with the BB treatment, provided a 9.0-fold increase in dietary boron but yielded only a 1.5-fold increase in plasma boron concentrations. Regardless of boron dietary treatment, fecal plus urinary excretion of boron accounted for nearly 100% of dietary boron intake with no evidence of boron accumulation over time. Lack of boron accumulation and relatively small changes in blood boron values during a substantial increase in dietary boron support the concept of boron homeostasis. In subjects fed BMg, SB decreased the percentage of dietary calcium lost in the urine but increased that percentage in volunteers fed SMg, a relation that may be important in understanding metabolic mineral disorders that perturb calcium balance. Reduced calcium absorption during SAl suggests that aluminum supplementation should be limited or at least monitored in postmenopausal women prone to excessive calcium loss. Decreased total urinary oxalate during SB in BMg subjects indicates a possible role for boron in the control of urolithiasis during low-magnesium nutriture.

Dietary boron modifies the effects of vitamin D3 nutrition on indices of energy substrate utilization and mineral metabolism in the chick.

An experiment was designed to test part of the hypothesis that physiologic amounts of dietary boron enhance utilization of or, alternatively, compensate for, inadequate concentrations of active vitamin D metabolites to normalize energy substrate utilization and mineral metabolism. Day-old cockerel chicks were fed a ground corn, high-protein casein, corn oil-based diet (< or = 0.18 mg B/kg) supplemented with physiologic amounts of boron (as orthoboric acid) at 0 (non-PSB) or 1.4 (PSB) mg/kg and vitamin D3 (as vitamin D3 powder in corn endosperm carrier) at 3.13 (inadequate, IVD) or 15.6 (adequate, AVD) micrograms/kg. After 26 days, IVD decreased food consumption and plasma calcium concentrations and increased plasma concentrations of glucose, beta-hydroxybutyrate, triglycerides, triiodothyronine, cholesterol, and alkaline phosphatase activity. In the IVD chicks, PSB returned plasma glucose and triglycerides to concentrations exhibited by the AVD chicks and increased food consumption in both IVD and AVD chicks. Histologic findings suggested that PSB enhanced maturation of the growth plate. A ninefold increase in dietary boron yielded only a two-fold increase in plasma boron concentration and no increase in femur boron concentration, which suggests that boron is under homeostatic control. The findings suggest that boron acts on at least three separate metabolic sites because it compensates for perturbations in energy substrate utilization induced by vitamin D3 deficiency, enhances major mineral content in bone, and, independently of vitamin D3, enhances some indices of growth cartilage maturation.

Boron affects energy metabolism in the streptozotocin-injected, vitamin D3-deprived rat.

Dietary boron, in amounts usually found in human diets comprised mainly of fruits and vegetables, apparently affects both mineral and energy metabolism. Therefore, the effects of boron on a model system with a perturbed metabolic insulin-vitamin D3 axis was examined. Weanling male rats were fed a ground corn-high protein casein-corn oil-based diet (0.06 micrograms B/g and no supplemental vitamin D3) supplemented with B (as orthoboric acid) at 0 or 2.4 mg/kg. After 55 days, all rats were equilibrated in individual metabolic cages. After another 6 days, one half of the rats in both dietary groups were injected intraperitoneally with streptozotocin (STZ). All rats were killed 3 days after STZ treatment. STZ affected many aspects of energy metabolism. In the non-STZ rats, supplemental dietary boron substantially depressed plasma insulin, plasma pyruvate concentrations, and creatine kinase activity and increased plasma thyroxine (T4) concentrations. The finding that boron did not affect growth, but did affect several indices of energy metabolism in the non-STZ animals suggests that boron functions as a regulator of energy metabolism in the rat. A decrease in plasma aspartate transaminase activity (an indicator of enhanced cell membrane integrity) in the non-STZ rats suggests that boron exerts a protective influence over normal liver metabolism.

Effects of dietary boron on calcium and mineral metabolism in the streptozotocin-injected, vitamin D3-deprived rat.

Dietary boron, in concentrations similar to that found in human diets comprised mainly of fruits and vegetables, affects both mineral and energy metabolism. Therefore, the effects of boron on a model system with a perturbed metabolic insulin-vitamin D3 axis was examined. Weanling male rats were fed a ground corn-high protein casein-corn oil-based diet (0.06 mg B/kg; no supplemental vitamin D3) supplemented with B (as orthoboric acid) at 0 or 2.4 mg/kg. After 55 days, all rats were equilibrated in individual metabolic cages for 6 days. After another 6 days, one half of the rats in both dietary groups were injected intraperitoneally with streptozotocin (STZ). All rats were killed 3 days after STZ treatment. STZ affected many aspects of mineral metabolism as expected. Plasma ionized calcium concentrations fell by approximately 10% in STZ-treated rats. Brain and heart mineral metabolism was spared from the toxic effects of STZ whereas spleen mineral metabolism was especially vulnerable to STZ. Supplemental dietary boron increased urinary excretion of calcium in the non-STZ rats but did not affect the plasma concentrations of alkaline phosphatase, ionized calcium or the concentration of calcium in the brains, lungs, kidneys and spleens of those animals. Supplemental dietary boron temporarily reduced the abnormally elevated renal excretion of albumin, potassium and sodium during the acute phase of diabetes mellitus. On the other hand, physiological amounts of dietary boron exacerbated the abnormally elevated rate of collagen breakdown in the STZ animal. Finally, boron may have indirectly affected heart mineral metabolism because dietary boron did not affect cardiac boron concentrations but did affect cardiac copper, calcium, manganese, molybdenum and phosphorus concentrations, primarily in non-STZ rats. The findings suggest that dietary boron has both protective and regulatory roles in mineral metabolism.