Growth and the nutritional status of nonsteroid-dependent asthmatic children

Nonsteroid dependent children were evaluated to determine the effect of asthma on growth and nutritional status. No significant differences were observed for the growth of asthmatics and control groups. In addition, dietary records indicated asthmatics met or exceeded the recommended daily allowance for total calories and nutrients.

Partial characterization of rat marrow stromal cells

Fibroblast-like rat marrow stromal cell (CFU-F) cultures have been characterized in terms of their responsiveness to calciotropic hormones, metal ions, the nonsteroidal antiinflammatory drug, and by their putative paracrine role in the maintenance of active populations of osteoblasts at the marrow-bone interface. These studies indicate that CFU-Fs lack a complete osteoblast signature. Subconfluent CFU-Fs grown in the presence or absence of 10(-7) M dexamethasone lack receptors for PTH and calcitonin, and fail to show enhanced cAMP or cGMP responses to 10(-7) M 1-34 PTH (rat), or any evidence of osteocalcin production [+/- 10(-9) M 1,25-(OH)2D3]. Low concentrations of fluoride [10(-12) and 10(-9) M] stimulated CFU-F grown in vitro in serum-free media, though higher levels (10(-7) and 10(-6) M), inhibited growth in vivo and in vitro. Aluminum (10(-12)-10(-7) M) and ibuprofen (10(-7) M) did not alter normal growth patterns, indicating an action on bone cells more differentiated than CFU-Fs. Serum-free conditioned medium (CM) from control and ovariectomized (OVX)/OVX+ dihydrotachysterol-Rx rat CFU-F cultures was mitogenic for neonatal rat calvarial osteoblasts in vitro, but not for ROS 17/2.8 cells. The studies affirm the mesenchymal-like character of CFU-Fs and project their significant role in sustaining functional endosteal osteogenic cell populations.

The aluminum content of parenteral solutions: current status

Aluminum contaminates several chemical compounds that are administered intravenously to patients. The most highly contaminated are calcium and phosphate salts, followed by albumin and heparin. Parenteral administration of aluminum bypasses the gastrointestinal tract, which serves as a protective barrier to aluminum entry into the blood. In the past, parenteral administration of aluminum as a contaminant of water used in hemodialysis and of casein hydrolysate, the former source of protein in parenteral nutrition solutions, was associated with a low-turnover osteomalacic bone disease and, in the case of uremic patients, encephalopathy. Groups currently at risk for aluminum accumulation in tissue resulting from parenteral administration include premature infants receiving long-term parenteral nutrition and patients receiving plasmapheresis therapy with albumin. Both groups may develop metabolic bone disease; the pathogenesis may involve aluminum. The Food and Drug Administration is currently considering regulation of aluminum in fluids used for parenteral nutrition. No changes are presently proposed with regard to albumin.

Skeletal effects of sodium fluoride during hypokinesia

This study tested the capacity of fluoride (F) to prevent the disuse-associated reduction in bone formation/growth. Suspending young male Wistar rats by the tail for 2-2.5 weeks reduced femoral cortical (P less than 0.05) and trabecular (P less than 0.01) bone areas. Tetracycline labelling showed that the decrement in cortical area was largely due to a reduction in the percent periosteal mineralizing surface (PsMS). Periosteal mineral apposition rate (PsMAR) was not affected. Endosteal mineralizing surface (EsMS) and mineral apposition rate (EsMAR) were significantly stimulated spontaneously during the second week of suspension. F treatment (5 mg/kg/day i.p.) prevented the loss in bone area, and established a trend toward increased PsMS without affecting EsMS and EsMAR. None of these changes are associated with alterations in serum Ca, P or osteocalcin. F treatment in hypokinetic animals caused a decrease in serum PTH (-21% compared to control; P = 0.001). We conclude that F prevents the development of hypokinetic osteopenia in rats.

Elevated serum aluminum levels in severely burned patients who are receiving large quantities of albumin

Aluminum contaminates various fluids that are used in intravenous therapy, and it is associated with bone disease and encephalopathy. Albumin is highly contaminated with aluminum, which is eliminated primarily by renal excretion. Patients with burns receive large quantities of albumin and have impaired renal function, which puts them at hypothetical risk for aluminum loading. To assess the risk of aluminum loading we analyzed sera from 12 patients with burns for aluminum concentrations. Serum aluminum concentration was elevated in 8 of the 12 patients, and levels were at or near toxicity in 3 of the 8. Serum aluminum and serum creatinine levels directly correlated, r = 0.71 and p less than 0.005. No relation was found between serum aluminum and amount of albumin received. However, patients with the highest serum aluminum levels were the most severely burned and none survived. Thus patients with burns who are receiving albumin are at risk for aluminum loading. Impaired renal function contributes to aluminum retention.

Serum markers of bone formation in parenteral nutrition patients

Bone gamma-carboxyglutamic acid containing protein (BGP) has been utilized effectively as a serum marker of bone turnover in healthy normals and in individuals with a variety of metabolic bone disorders including postmenopausal osteoporosis and Paget's disease. The utility of this serum marker in other bone disorders, including that associated with the maintenance of patients on long-term parenteral nutrition, still requires definition. Because of our interest in this clinical syndrome and the availability of serum and of bone formation rates (BFR) measured directly from double tetracycline labeling in 11 long-term parenteral nutrition patients, we measured BGP levels in these patients and attempted to correlate this measure with BFR. Serum vitamin D metabolites, immunoreactive parathyroid hormone (PTH), and alkaline phosphatase (alk phos) were also measured. Serum BGP was only weakly and not significantly correlated (r = 0.24, p = NS) with bone formation rate for the group as a whole. However, in a subgroup of 10 patients without hyperparathyroidism, there was strong and significant correlation (r = 0.81, P less than 0.01) between BGP and BFR. There was also a strong correlation between bone formation rate and serum 1,25 dihydroxyvitamin D [1,25(OH)2D] levels (r = 0.89, P less than 0.01, n = 11). The mechanism of this association could not be established. A correlation of borderline significance was observed between bone formation rate and serum alk phos (r = 0.60, P = 0.05, n = 11). The current data suggest that additional studies may help to more fully define the utility of serum measurements in quantifying bone dynamics in parenteral nutrition patients, and that measures of vitamin D metabolites, BGP, and alk phos may prove useful.

A simplified screening test for the diagnosis of allergy

The Quidel allergy screen is a relatively rapid (less than 2 hours) multiallergen dipstick method for detecting specific immunoglobin E antibodies in serum. It was developed to answer the need of primary physician nonspecialists in allergy for a convenient in-office screening test for diagnosing allergy. The new test was evaluated against the benchmark diagnostic skin tests and the radioallergosorbent serologic tests for sensitivity, specificity, accuracy, and technical feasibility in an office setting. It was found that while the Quidel allergy screen lacks the specificity of the standard tests, its overall sensitivity, as defined by the percentage of patients with positive skin reactions who also tested positive with the Quidel screen (68%), its ease of use, and its rapidity warrant its consideration as a screening tool for confirming a possible case of allergy.

Hypocalcemia complicating deferoxamine therapy in an infant with parenteral nutrition-associated aluminum overload: evidence for a role of aluminum in the bone disease of infants

Aluminum (Al) contaminates total parenteral nutrition (TPN) solutions given to infants, and high levels of Al have been demonstrated in their bone, serum, and urine. However, it is uncertain whether Al at current levels of contamination of TPN solutions is harmful to bone. We report an 8-month-old infant who developed osteopenic bone disease while receiving TPN, which did not respond to large amounts of calcium, phosphate, and vitamin D2. Serum and urine Al levels were greatly elevated and fell after a short course of deferoxamine. However, shortly after treatment began, serum calcium levels fell in the absence of hypercalciuria. We postulate that chelation of Al from this patient's bone permitted increased bone calcium uptake. This would suggest that Al at current levels of contamination of TPN solutions may impair bone calcium uptake and thus contribute to the pathogenesis or exacerbation of TPN-related osteopenia.

Effects of aluminum on the liver following high-dose enteral administration to rats

Parenteral administration of aluminum (Al) to animals can result in hepatobiliary dysfunction, including elevated total serum bile acid concentration, reduced bile flow, and reduction of mixed function oxidase activities. Despite substantial hepatic Al accumulation, biliary Al excretion is negligible. We studied the effects of enteral administration of pharmacologic doses of Al to rats in order to see if by this route Al also produced hepatobiliary dysfunction or if biliary Al excretion was enhanced following enteral administration, protecting the liver from the effects of Al. Six rats were given 100 mg/kg/day of Al for 14 days as Al citrate by duodenal cannula. Pair-fed littermate controls were given sodium citrate. Serum Al and urinary Al/creatinine were significantly higher in Al-fed rats than in controls. Liver Al was significantly increased in the Al-fed group, but very low when compared to liver Al concentration with intravenous Al administration. Biliary Al was only 2 +/- 1% of urinary Al in the experimental group. Serum bile acid concentration and bile flow were not different between groups. We conclude that Al given in pharmacologic doses is absorbed but does not accumulate in the liver. We hypothesize that a slow rate of Al absorption may not overwhelm plasma transferrin carrying capacity or renal Al excretory capacity.

Aluminum in parenteral products: medical perspective on large and small volume parenterals

Bone abnormalities may complicate parenteral nutrition (PN) therapy given to patients. Bone disease, manifested by reduced bone formation and demineralization in adults, and poor mineralization in infants, is associated with bone aluminum accumulation at the mineralizing surface. Aluminum was first shown to contaminate casein hydrolysate, the PN protein source. Substitution of amino acid solutions, low in aluminum, reduced bone aluminum and improved bone formation in adults. Aluminum also accumulates ten-fold in the bones of premature infants receiving chronic PN. Present sources of aluminum in PN are calcium and phosphate salts, albumin, and heparin. Although increased bone aluminum in infants is not proven to cause disease, use of deferoxamine in one infant produced hypocalcemia. This suggested that chelation of bone aluminum by deferoxamine increased bone calcium uptake. Thus aluminum in bone may impair bone calcium uptake and may contribute to the pathogenesis of PN-related bone disease in infants. Another complication of PN therapy in infants is cholestatic liver disease, manifested by reduced bile flow, and, occasionally, gallstones. Aluminum has been found to accumulate in the livers of these infants, and there is experimental evidence that aluminum can reduce bile flow both in rats and in piglets. Aluminum contamination of PN solutions puts infants at increased risk for complications of PN therapy; amounts of aluminum in PN solutions should therefore be minimized.

Treatment of hay fever. Allergen avoidance and medication to control symptoms

Therapy for hay fever should begin with environmental control, because sometimes avoidance of allergens is all that is needed to adequately control symptoms. If not, useful medications include antihistamines, decongestants, combinations of the two, prescription nasal sprays, and allergy immunotherapy. The best method and correct dosage are important, both to ensure patient comfort and to prevent the side effects of allergic disorders.

Absence of hyperparathyroidism in severe liver disease

Elevated serum levels of intact parathyroid hormone (PTH) have been reported in severe versus mild biliary cirrhosis. The aim of this study was to determine whether hyperparathyroidism was present in severe liver disease on the basis of the inability of the liver to catabolize the hormone. Because biologic activity resides in the amino terminal, and amino terminal PTH determinations have not been routinely made in liver disease, it is possible that hyperparathyroidism was previously missed in these patients. Accordingly, we obtained fasting blood from 11 patients with severe liver disease and 8 age-matched controls. We measured intact, amino terminal, and mid-region PTH, vitamin D metabolites, bone gamma carboxyglutamic acid protein (BGP), ionized calcium, phosphorus, magnesium, and liver function tests. Serum levels of PTH were normal with all assays and 1,25(OH)2D levels were not elevated. These findings argue against the possibility that hyperparathyroidism plays a role in the pathogenesis of hepatic osteodystrophy.

Metabolic bone disease of total parenteral nutrition: course after changing from casein to amino acids in parenteral solutions with reduced aluminum content

Bone disease with total parenteral nutrition (TPN) has been attributed to aluminum loading or vitamin D therapy. We studied 17 patients who first received TPN containing casein hydrolysate with high Al and ergocalciferol (25 micrograms/d) for 6-72 mo followed by TPN containing amino acids with reduced Al and ergocalciferol (5 micrograms/d) for 9-58 mo. We also did a cross-sectional study of 22 patients receiving casein and ergocalciferol (25 micrograms/d) compared with 46 patients receiving amino acids and ergocalciferol (5 micrograms/d) for 6-58 mo. Bone formation was higher and osteoid area, bone-surface stainable Al and total bone Al were lower with amino acid TPN than with casein TPN. Bone formation varied inversely with both plasma Al and bone-surface Al, suggesting that plasma or bone-surface Al, acquired during TPN, can reduce bone formation and lead to patchy osteomalacia. Serum levels of iPTH and 1,25-dihydroxyvitamin D were higher with amino acid TPN.

Aluminum-associated hepatobiliary dysfunction in rats: relationships to dosage and duration of exposure

Aluminum may contaminate parenteral nutrition solutions and accumulate in bone and liver of patients receiving this therapy. Although aluminum exposure is associated with low-turnover osteomalacia, there are few studies of hepatotoxicity. We therefore studied the effects of aluminum given to rats on total serum bile acid concentration and bile flow to determine if aluminum administration could produce abnormalities. Aluminum was given intravenously as follows: 5 mg/kg daily for 7 or 14 days and 1 mg/kg for 14 days. Hepatic aluminum was high in treated rats and undetectable in controls. Total serum bile acid concentrations were significantly higher in treated rats than in pair-fed controls with higher concentrations after 14 days than after 7 days. Bile flow was reduced by 33% in rats given 5 mg/kg but not in rats given 1 mg/kg. Hepatic aluminum correlated inversely with bile flow but not with serum bile acid concentration. Aluminum exposure in rats is associated with elevated serum bile acid concentration and diminished bile flow and may play a role in the pathogenesis of parenteral nutrition-induced hepatobiliary dysfunction.

Persistent allergic rhinitis in older patients: therapies worth trying

Allergic rhinitis (hayfever) is a common problem found in the geriatric population. This problem should be aggressively treated with environmental control, prescription nasal sprays and/or antihistamines (if tolerated). Allergy immunotherapy can be a very effective treatment for the elderly, without the side effects commonly found when hayfever medication is used.

Heterogeneity of bone histology in parenteral nutrition patients

The characteristics of bone disease associated with parenteral nutrition are controversial. To further elucidate the contribution of aluminum deposition to this syndrome and the spectrum of pathology in patients supported by current regimens utilizing crystalline amino acids, quantitative histomorphometry and staining for Al were performed on iliac crest bone biopsies from 26 long-term parenteral nutrition patients and 16 normal volunteers. Compared with normal subjects, median trabecular bone area (TBA) for a group with positive Al staining (n = 14) who were exposed to casein hydrolysate was significantly less (12.9% vs 20.7, p less than 0.05) as was the median rate of bone formation (RBF) (29 micron2 X mm-2 X d-1 vs 360, p less than 0.05). A variety of abnormal histological findings were present in patients without positive aluminum stains (n = 12) who were supported solely by regimens utilizing crystalline amino acids. However, neither decreased TBA (median TBA = 15.3%) nor decreased RBF (median RBF = 126 micron2 X mm-2 X d-1) was uniformly characteristic of the latter patient group.

Hepatic abnormalities associated with aluminum loading in piglets

Cholestasis is a common complication of total parenteral nutrition (TPN) in infants. A contributing factor to the hepatic dysfunction may be a contaminant of the TPN solution, such as aluminum, that accumulates in liver and may act as a hepatotoxin. To study the hepatic effects of aluminum, growing piglets were given daily intravenous injections of aluminum, 1.5 mg/kg, for 50 days; pair-fed controls were given heparinized saline. At sacrifice, liver and serum were obtained. Liver was analyzed for histopathology and for aluminum content and localization. The hepatocyte lysosomes of the experimental group showed aluminum peaks by x-ray microanalysis, whereas the control group did not. No differences in ultrastructure were noted between the two groups when examined by electron microscopy. Mean serum total bile acid levels (27.8 +/- 15.9 SD vs 6.3 +/- 1.5 mumol/liter, p less than 0.05), mean alkaline phosphatase (309 +/- 108 vs 180 +/- 27 IU/liter, p = NS), and mean hepatic copper content (24.8 +/- 4.5 vs 14.4 +/- micrograms/g dry weight, p less than 0.01), were elevated in the aluminum-loaded piglets, indicating that cholestasis may have been produced. Also, a small but significant reduction in serum levels of 25 hydroxy-vitamin D was found in the aluminum-loaded piglets, suggesting that vitamin D hydroxylation may be impaired. Inasmuch as lysosomal contents are excreted into the bile, aluminum accumulation in lysosomes may alter lysosomal function and possibly affect bile flow or content.

The effects of aluminum loading on the renal response to parathyroid hormone in the vitamin D-replete rat

Aluminum (Al) may cause vitamin D-resistant osteomalacia and depress the serum levels of immunoreactive parathyroid hormone (iPTH) in patients treated with maintenance dialysis and those on total parental nutrition (TPN). Both conditions have been associated with low serum levels of 1,25(OH)2-vitamin D (1,25(OH)2D). Al may inhibit PTH secretion in vitro; however, induction of hypocalcemia can enhance endogenous PTH secretion in Al-loaded dogs and TPN patients. Despite hypocalcemia and/or increased endogenous iPTH levels, Al-loaded TPN patients fail to show the expected rise in serum 1,25(OH)2D levels. Such observations suggest that Al may impair the renal response to PTH. We studied vitamin D-replete rats given Al or saline vehicle IP for 5 days. Al and control rats then received a saline infusion with an IV bolus of PTH 1-34. Urinary cyclic AMP and P excretion rose in Al and control rats by 1 hr post-PTH, without differences between the groups. Serum P and ionized Ca levels were not different between Al and control rats. In other Al and control rats, serum 1,25(OH)2D levels were measured after saline without PTH. Serum 1,25(OH)2D levels were higher in controls given PTH than in those without, but 1,25(OH)2D levels were not different between Al rats given PTH and those with none. Thus, aluminum does not affect cyclic AMP or P excretion but may impair 25(OH)D-1 alpha-hydroxylase activity in response to PTH.

Aluminum does not accumulate in teenagers and adults on prolonged parenteral nutrition containing free amino acids

Prolonged total parenteral nutrition (TPN) with solutions containing hydrolyzed casein has been associated with aluminum accumulation in patients with bone disease. We investigated the effects of free amino acids in TPN solution on plasma, urine, and bone aluminum in six patients, five of whom had symptoms of bone disease or documented demineralization. No evidence of aluminum accumulation was found. TPN with free amino acids, containing 42 micrograms aluminum per liter or less, does not lead to aluminum loading in adolescents or adults.