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Biomedical subjects

L A Fitzpatrick

Publications and source records attributed to L A Fitzpatrick.

At least 91 records · Page 5Linked to original sources
PubMed1995

Oestrus detection techniques and insemination strategies in Bos indicus heifers synchronised with norgestomet-oestradiol.

Oestrus was synchronised in 57 Bos indicus heifers using norgestomet-oestradiol and pregnant mare serum gonadotrophin. Oestrus was detected by observations made at six-hourly intervals, using oestrogen-treated and chin-ball harnessed steers, heatmount detectors, tail-paint and visual observation. Heifers were inseminated once at either a fixed time of 49.2 +/- 0.4 h (mean +/- SE; n = 29) after implant removal or 12.6 +/- 1.5 h (n = 28) after oestrus was detected. The mean (+/- SE) time to the onset of oestrus was 47.1 +/- 1.9 h, while 90% of heifers recorded in oestrus were detected within 66 h of implant removal. Heatmount detectors were significantly more efficient at detecting oestrus than chin-ball harnessed steers, tail paint or visual observation (P < 0.001). A higher pregnancy rate was obtained in heifers inseminated after oestrus detection compared with heifers inseminated at a fixed-time (57.1 vs 34.5%; P = 0.043) and a higher pregnancy rate was obtained in heifers classified as easy to inseminate compared with heifers classified as difficult to inseminate (57.8 vs 0%, P < 0.001). We conclude that heatmount detectors are an efficient means of detecting oestrus in synchronised B indicus heifers and that pregnancy rates can be increased when insemination follows oestrus detection compared with a fixed-time insemination regimen.

Animals↗
PubMed1995

Spontaneous oscillations of intracellular calcium in single bovine parathyroid cells may be associated with the inhibition of parathyroid hormone secretion.

PTH secretion is tightly regulated by extracellular calcium ([Ca2+]e) and in turn regulates calcium homeostasis through its action on target tissues. We investigated the mechanism and physiological significance of intracellular calcium ([Ca2+]i) levels in relation to the secretion of PTH in single bovine parathyroid cells. [Ca2+]i was recorded using digital imaging microscopy, and secretion of PTH was correlated in the same cell using the reverse hemolytic plaque assay. In individual parathyroid cells, oscillations of [Ca2+]i were present in response to specific stimuli. Like secretory activity, response to [Ca2+]e concentrations was heterogeneous. Oscillations of [Ca2+]i occurred spontaneously in 22% of cells at inhibitory concentrations of [Ca2+]e. Oscillations were present only in high [Ca2+]e (> or = 1.8 mM) and not noted at lower concentrations of [Ca2+]e. The interval and amplitude of [Ca2+]i oscillations were 42 +/- 2 sec, and 20 +/- 1 nM (mean +/- SE), respectively. Oscillations were rapidly abolished when [Ca2+]e was removed by EGTA, and this effect was reversible. Addition of Mg2+ or polycationic antibiotics such as neomycin resulted in an [Ca2+]i spike, but oscillations were absent. Lanthanum, which blocks Ca2+ influx through calcium channels in various cells, rarely caused oscillations even in the presence of high concentrations of [Ca2+]e. To test the role of cAMP in [Ca2+]i oscillations, we added the beta-agonist isoproterenol. The addition of isoproterenol, however, did not cause oscillations. The number of cells that released PTH was significantly lower in cells with oscillations compared with cells without oscillations. We suggest that spontaneous [Ca2+]i oscillations are due to the influx of [Ca2+]e through ion channels rather than release from [Ca2+]i stores and may be a specific intracellular signal associated with inhibition of PTH secretion.

Animals↗
PubMed1995

Hormone concentrations in the caudal vena cava during the first ovarian follicular wave of the oestrous cycle in heifers.

Changes in pulsatile secretion of LH, FSH, oestradiol and progesterone were related to the growth phase, early plateau phase and regression phase of the first ovarian dominant follicle of the oestrous cycle in Bos indicus heifers. Relationships between these hormones during the three phases were also investigated. Accurate measurements of episodic ovarian steroid secretion were obtained by catheterizing the caudal vena cava via the lateral saphenous vein; the tip of the catheter was positioned just cranial to the ovarian vein using transrectal ultrasonography. Pulsatile secretion of oestradiol was increased only during the growth phase of the dominant follicle and was associated with high frequency release of LH pulses. However, mean concentrations of oestradiol were reduced when the dominant follicle attained its maximum diameter. Between the growth and plateau phases, as the amount of progesterone released increased and oestradiol released decreased, LH pulse frequency and mean concentration of LH decreased. Pulses of LH released were followed within 15 min by increases in mean concentrations of oestradiol (P < 0.001); however, there was no apparent relationship between LH and progesterone release (P = 0.19). Although there was little evidence of pulsatile release of FSH, mean concentrations of FSH were increased by 0.2 ng ml-1 (P = 0.04) during the plateau phase, which was on average 2.1 days before the day of emergence of the second dominant follicle of the oestrous cycle. This increase in FSH, in conjunction with the decrease in secretion of oestradiol, may be an indication of the loss of functional dominance by the first dominant follicle of the oestrous cycle.

Animals↗
PubMed1995

Sequential changes in ovarian follicular dynamics in Bos indicus heifers before and after nutritional anoestrus.

This study examined the effects of live mass on ovarian follicular dynamics in heifers before and after the onset of nutritional anoestrus. The effects of decreased live mass on secretion of progesterone, LH and FSH were also investigated. Ovarian characteristics were monitored in 16 postpubertal Brahman heifers using daily transrectal ultrasonography. After two normal oestrous cycles, 11 heifers (treatment group) were allocated to a restricted diet, until the cessation of their oestrous cycles, that resulted in a decrease in live mass of 0.8 kg day-1. Heifers were then fed an ad libitum diet, resulting in increasing live mass until resumption of oestrous cycles. Five heifers (control group) were fed an unrestricted diet throughout the experimental period. The concentrations of progesterone in plasma were monitored twice a week and the concentrations of LH and FSH were determined on day 6 after ovulation, before initiation of dietary restriction, after a 17% decrease in live mass and after the onset of anoestrus in the treatment group. Onset of anoestrus was preceded by linear decreases in the size of ovarian follicles and corpora lutea, and in the persistence of the first dominant follicles of oestrous cycles. These changes were proportional to the decrease in live mass (P < 0.001). The frequency of pulses of LH or mean concentration of FSH on day 6 of the oestrous cycle were not changed after a 17% decrease in live mass, and did not increase following the onset of anoestrus, although concentrations of progesterone were < 0.2 ng ml-1, suggesting that release of LH was suppressed at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Anestrus↗
PubMed1995

Physiological effects of undernutrition on postpartum anoestrus in cows.

The focus of this review is the physiological effects of undernutrition on ovarian follicle growth and the occurrence of ovulation in postpartum cows. Evidence suggests that moderate levels of underfeeding, before or after calving, may interfere with the mechanism(s) of final follicle maturation and ovulation, whereas more pronounced nutritional deficiencies may affect the mechanism(s) regulating dominant follicle size and the dynamics of dominant follicle growth and regression. Severe undernutrition may result in the absence of follicles > 5 mm in diameter. These changes are consistent with likely effects of reduced LH or FSH secretion that have been associated with inhibition of both tonic and surge release of GnRH from the hypothalamus. As yet, there is no direct evidence for local effects of undernutrition on ovarian function in cows, and studies examining this tissue often ignore dynamic interdependencies between the hypothalamus, anterior pituitary gland, and the ovaries, and possible nutritional modulation of ovarian feedback mechanisms that affect gonadotrophin secretion. Further research is required to elucidate nutritional effects on the positive feedback regulation of gonadotrophin secretion and on the expression of behavioural oestrus. Further studies are also needed to determine whether nutritional or metabolic state may influence ovarian function directly in a manner that affects the duration of postpartum anoestrus and fertility in postpartum cows.

Anestrus↗
PubMed1994

Relation of coronary calcium determined by electron beam computed tomography and lumen narrowing determined by autopsy.

Coronary calcium determined by electron beam computed tomography (CT) has not been systematically evaluated regarding prediction of histopathologic atherosclerotic disease. Furthermore, gender specificity has not been examined. The 3 major epicardial arteries were dissected from 13 consecutive hearts (5 women and 8 men) after autopsy. Each artery was straightened and scanned using CT in contiguous 3 mm thick cross sections. After imaging, histologic sections were prepared at corresponding intervals and luminal area obstruction determined by planimetry. Electron beam CT scans were analyzed to determine coronary calcium area (i.e., tomographic area with CT density > 130 Hounsfield units). A total of 522 histologic specimens were examined and paired with corresponding CT scans (182 in women, 340 in men). Receiver-operating characteristic (ROC) analysis was used to define site specificity of calcium area for luminal area narrowing by atherosclerosis. ROC curve areas for segmental CT calcium and prediction of atherosclerosis representing mild, moderate, or severe disease were, respectively, 0.712, 0.843, and 0.857 for women and 0.732, 0.793, and 0.841 for men. Curves relating false-positive rate (1-specificity) to predefined degrees of atherosclerotic narrowing versus calcium area were curvilinear. In both women and men, calcium areas on the order of 1 mm2/coronary segment were necessary to predict at least mild atherosclerosis with a false-positive rate of 0% (i.e., 100% specificity), whereas a calcium area > 3 mm2 was necessary to predict the same result for severe disease. In conclusion, coronary artery calcium area as determined by electron beam CT has the potential to predict segmental histopathologic coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Paracrine interactions among parathyroid cells: effect of cell density on cell secretion.

Cell-cell interactions are important in the regulation of endocrine cell secretion. To investigate the possibility that cell communication may alter the regulation of parathyroid cell secretion, we utilized the reverse hemolytic plaque assay (RHPA) to measure parathyroid hormone (PTH) release from individual cells. Bovine parathyroid cells were dispersed and plated with protein A-conjugated erythrocytes at cell densities ranging from 0.9 to 36 x 10(2) cells/cm2 in 0.2 mM calcium. Cell populations were greater than 98% homogenous as determined by immunocytochemistry and in situ hybridization for PTH mRNA. Plaques were developed and data analyzed for the amount of PTH per cell released (plaque area in microns 2 x 10(4)) and the determination of cell recruitment (% plaques formed). A positive correlation existed between parathyroid cell density and the amount of PTH released. As the distance between cells increased, the plaque area (amount of PTH released per cell) decreased (ranging from 1.0 x 10(4) microns 2 at 0.9 x 10(2) cells/cm2 versus 1.6 x 10(4) microns 2 at 36 x 10(2) cells/cm2). The percentage of cells releasing PTH (recruitment) also decreased (16% at 0.9 x 10(2) cells/cm2 versus 47% at 36 x 10(2) cells/cm2). These data suggest that parathyroid cells in close proximity are stimulated to secrete more hormone than those at lesser densities. In addition, parathyroid cells are recruited to secrete PTH when plated at high density. Factor(s) released by the parathyroid cell may increase cell responsiveness and stimulate secretion in a paracrine fashion.

Animals↗
PubMed1994

Effects of transforming growth factor beta (TGF beta) and 1,25 dihydroxyvitamin D3 on the function, cytochemistry and morphology of normal human osteoblast-like cells.

Individually, transforming growth factor beta (TGF beta) and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) alter the growth and differentiation of normal and transformed osteoblast-like (OB) cells. Although recent evidence suggests interactions between TGF beta and 1,25(OH)2D3 may occur, little is known of the individual or combined effects of these hormones on the expression of the osteoblast phenotype at the cytochemical and biochemical levels in normal human OB (hOB) cells. Primary cultures of hOBs were treated with TGF beta (0.001-10 ng/ml) and 1,25(OH)2D3 (0.1 pM-100 nM) either alone or in combination. TGF beta and 1,25(OH)2D3 stimulated spindle-shaped cells to become stellate in appearance and increased the number of cytoplasmic processes. TGF beta increased 3H-thymidine incorporation and 1,25(OH)2D3 reduced this effect. Conversely, procollagen type-I synthesis and secretion were increased in a dose-dependent manner in the presence of TGF beta but were not significantly affected in the presence of 1,25(OH)2D3. TGF beta and 1,25(OH)2D3 each marginally increased alkaline phosphatase (ALP) activity, but the combination synergistically increased ALP activity in a dose- and time-dependent manner at the cytochemical and biochemical level (three to tenfold over vehicle controls; n = 12). In contrast, TGF beta reduced 1,25(OH)2D3-stimulated osteocalcin secretion. These data suggest that TGF beta stimulates hOB cells to actively produce collagen matrix and proliferate. The combination of TGF beta and 1,25(OH)2D3, however, produces a synergistic increase in ALP activity and maintenance of collagen synthesis. 1,25(OH)2D3 stimulation may induce cells to advance to an endstage where cell proliferation is reduced and osteocalcin expression is promoted. Interactions between TGF beta and 1,25(OH)2D3 may represent important steps in the regulation of osteoblast differentiation and matrix production.

Alkaline Phosphatase↗
PubMed1994

Age- and gender-related changes in the distribution of osteocalcin in the extracellular matrix of normal male and female bone. Possible involvement of osteocalcin in bone remodeling.

With increasing age, bone undergoes changes in remodeling that ultimately compromise the structural integrity of the skeleton. The presence of osteocalcin in bone matrix may alter bone remodeling by promoting osteoclast activity. Whether age- and/or gender-related differences exist in the distribution of osteocalcin within individual bone remodeling units is not known. In this study, we determined the immunohistochemical distribution of osteocalcin in the extracellular matrix of iliac crest bone biopsies obtained from normal male and female volunteers, 20-80 yr old. Four different distribution patterns of osteocalcin within individual osteons were arbitrarily defined as types I, II, III, or IV. The frequency of appearance of each osteon type was determined as a percent of the total osteons per histologic section. The proportion of osteons that stained homogeneously throughout the concentric lamellae (type I) decreased in females and males with increasing age. The proportion of osteons that lack osteocalcin in the matrix immediately adjacent to Haversian canals (type III) increased in females and males with age. Osteons staining intensely in the matrix adjacent to Haversian canals (type II) increased in females and was unchanged in aging males. Osteons that contained osteocalcin-positive resting lines (type IV) increased in bone obtained from males with increasing age but were unchanged in females. Sections of bone immunostained for osteopontin (SPP-I), osteonectin, and decorin did not reveal multiple patterns or alterations in staining with gender or increasing age. We suggest that the morphology of individual bone remodeling units is heterogeneous and the particular morphologic pattern of osteocalcin distribution changes with age and gender. These results suggest that differences in the distribution of osteocalcin in bone matrix may be responsible, in part, for the altered remodeling of bone associated with gender and aging.

Adult↗
PubMed1994

Diffuse calcification in human coronary arteries. Association of osteopontin with atherosclerosis.

Coronary atherosclerosis is frequently associated with calcification of arterial plaque. To understand the mechanisms responsible for the formation of atherosclerotic calcification, we examined human coronary arteries for the presence and extent of mineral. In sections stained specifically for mineral, staining was diffuse and present in all atherosclerotic plaques. Hydroxyapatite was not detected in normal coronary artery sections. Distribution of hydroxyapatite coincided with a similar distribution of calcium detected by a radiodense pattern using contact microradiography of the same sections before cytochemical staining. By energy-dispersive x-ray microanalysis, the chemical composition of calcified sites was identical to hydroxyapatite (Ca10[PO4]6[OH]2), the major inorganic component of bone. Osteopontin is a phosphorylated glycoprotein with known involvement in the formation and calcification of bone and is regulated by local cytokines. Human coronary artery segments (14 normal and 34 atherosclerotic) obtained at autopsy were evaluated immunohistochemically using polyclonal antibodies generated against human osteopontin. Immunohistochemistry for osteopontin indicated intense, highly specific staining in the outer margins of all diseased segments at each calcification front; staining was evident throughout the entire plaque. Conversely, arterial segments free of atheroma and calcification and sections treated with nonimmune serum had no evidence of positive staining. Osteopontin, a protein involved in mineralization is specifically associated with calcific coronary atheroma and may play an important role in the onset and progression of this disease in human coronary arteries. The deposition of noncollagenous proteins such as osteopontin may regulate the presence or absence of calcification and ultimately alter vessel compliance.

Adult↗
PubMed1994

Direct effect of calcium channel antagonists on osteoclast function: alterations in bone resorption and intracellular calcium concentrations.

Osteoclasts attach to mineralized surfaces and resorb bone matrix, releasing calcium into the area surrounding the osteoclast. The production of high levels of extracellular calcium increases intracellular calcium concentrations ([Ca2+]i), and bone resorption is decreased. To study this mechanism, the dihydropyridine-sensitive L-type calcium channel antagonists PN 200-110, (-)202-791, and nifedipine were studied for their effects on bone resorption using the disaggregated osteoclast pit assay. Changes in [Ca2+]i after treatment with these compounds were determined with the fluoroprobe fura2. In osteoclast-enriched cultures, significant decreases in bone resorption were noted in the presence of PN 200-110 and (-)202-791. The decrease in bone resorption correlated with an increase in [Ca2+]i. To determine whether the effects of these compounds on osteoclasts were mediated via osteoblasts, proliferation and differentiation of rat osteoblast-like cells (ROS 17/2.8) were examined after the addition of these agents. There were no changes in osteoblast proliferation or differentiation, as determined by [3H]thymidine incorporation and specific activity of alkaline phosphatase, after treatment with these compounds at concentrations that inhibited bone resorption in the disaggregated pit assay. This lack of effect of calcium channel antagonists on osteoblast growth and differentiation at concentrations used to inhibit osteoclast function suggests that the effects of PN 200-110 and (-)202-791 on the osteoclast are not mediated via the osteoblast. In addition, conditioned medium recovered from ROS 17/2.8 cultures treated with PN 200-110 or (-)202-791 had no effect on pit formation compared to the conditioned medium from cell-free cultures. This lack of effect of calcium channel conditioned medium on bone resorption provides additional evidence that PN 200-110 and (-)202-791 are decreasing bone resorption directly by altering osteoclast function, not through osteoblast-osteoclast interactions. The addition of (-)202-791 or PN 200-110 to osteoclasts resulted in a dose-dependent rise in [Ca2+]i. These data suggest that calcium channel antagonists may bind to the calcium channel of the osteoclast and lock it in an open state, leading to increased [Ca2+]i and decreased bone resorption.

Animals↗
PubMed1994

Secretion of insulin-like growth factor binding protein-1 from individual hepatocytes.

The reverse hemolytic plaque assay (RHPA) uses complement-mediated red blood cell lysis to detect peptide secretion by individual cells. Initially, the RHPA was used to study the function of neurons and B lymphocytes. More recently, the RHPA has been adapted to measure hormone release from individual pituitary, parathyroid, luteal, and pancreatic islet cells. We have applied this technique to detect insulin-like growth factor binding protein-1 (IGFBP-1) secretion by a human hepatoma cell line (HepG2). We proposed that the technique of RHPA could be used to study peptide release from single hepatocytes in various defined conditions. Our goal was the study of the kinetics of IGFBP-1 secretion from hepatoma cells and rat hepatocytes and to determine the heterogeneity of the cell population regarding the secretion of IGFBP-1. To evaluate the optimal conditions of IGFBP-1 secretion by hepatoma cells and rat hepatocytes and to evaluate the influence of cell dispersion on hepatocyte's behavior, we evaluated three techniques of cell dispersion: trypsin digestion, collagenase digestion, and mechanical dispersion. We tested cell viability, determined the percentage of secreting cells versus non-secreting cells, and measured mean plaque area which is a function of the amount of IGFBP-1 secreted by an individual cell. We determined the optimal IGFBP-1 antibody dilution for the detection of secreted IGFBP-1 by hepatocytes, evaluated the initiation of IGFBP-1 secretion from cultured cells, and quantified time-dependent IGFBP-1 secretion. In addition to demonstrating the feasibility of measuring IGFBP-1 from a cultured cell line, we measured IGFBP-1 release from freshly dispersed rat hepatocytes.

Animals↗
PubMed1993

Distribution of noncollagenous proteins in the matrix of adult human bone: evidence of anatomic and functional heterogeneity.

The microanatomic distribution of several noncollagenous proteins (NCPs) in bone matrix was examined by immunohistochemical analysis of glycol-methyl methacrylate-embedded normal adult human bone biopsies. Osteopontin and bone sialoprotein stained throughout the lamellae of both trabecular and cortical bone. Cement lines (cortical and trabecular) and the mineralized matrix immediately adjacent to each Haversian canal were intensely stained. Osteocalcin was detected in cement lines; however, lamellar staining varied depending on the location within the individual unit of bone. In cortical bone, the inner concentric lamellae of osteons were often unstained but the outer lamellae were heavily stained for osteocalcin. Osteonectin was not detected in cement lines and in most specimens revealed a pattern similar to that of osteocalcin with respect to the absence of immunostaining within the inner concentric lamellae. Decorin was prominent in the perilacunar matrix, the canaliculi of osteocytes, and the matrix immediately adjacent to quiescent Haversian canals. Biglycan appeared evenly distributed throughout cortical and trabecular bone matrix. These results suggest that the incorporation of NCPs into matrix may vary depending on the stage of formation of individual bone units. The specific distribution and spatial relationship of these NCPs may be related to the function of each protein during bone resorption and formation. The distinct patterns of NCP localization in bone support the hypothesis that in addition to their structural and mineral-inducing properties, these proteins may influence the events associated with bone remodeling, such as recruitment, attachment, differentiation, and activity of bone cells.

Adult↗
PubMed1993

Noninvasive testing in the diagnosis of osteomalacia.

PURPOSE: Osteomalacia is associated with many clinical, radiographic, and biochemical abnormalities. Unfortunately, none of these are pathognomonic of the disorder, and histologic examination of a bone biopsy specimen is often necessary to confirm the diagnosis. Noninvasive methods of diagnosis would be preferable to decrease patient morbidity and increase cost-effectiveness. Previous studies addressing the adequacy of these methods were performed prior to the widespread availability of 1,25-dihydroxycalcitriol (1,25-(OH)2D3) and parathyroid hormone (PTH) levels. Therefore, we reviewed our experience with patients with biopsy-proven osteomalacia to determine if PTH or 1,25(OH)2D3 levels would serve a useful role in establishing the diagnosis of osteomalacia. METHODS: We retrospectively studied 17 patients who had biopsy-proven osteomalacia (defined as an osteoid volume greater than 10% and an osteoid width greater than 15 microns) in order to ascertain if their clinical presentation, biochemical profile, and radiographic features were sufficient to establish a diagnosis of osteomalacia. RESULTS: We found that 94% of our patients exhibited symptoms of osteomalacia, and all patients had at least one demonstrable sign of osteomalacia on examination. Biochemically, the patients presented a heterogeneous picture: 94% had an elevated alkaline phosphatase level; 47% had either a low serum calcium or phosphate (12% had both) level; urinary calcium excretion was low in 18%; and 25-(OH)D3 concentration was low in 29%. Levels of 1,25-(OH)2D3 were measured in eight patients; three had low values despite normal 25-(OH)D3 levels. PTH levels were elevated in 41% of patients in the absence of histologic evidence of hyperparathyroidism; however, these patients were noted to have multiple other abnormal clinical, biochemical, or radiograph features. Radiographically, 18% of patients had pseudofractures; the rest had nonspecific findings suggestive of osteomalacia. In summary, all patients had at least two of the following abnormalities: low calcium, low phosphate, elevated alkaline phosphatase, or a radiographic finding suggestive of osteomalacia. CONCLUSION: We conclude: (1) a careful history and physical examination remain important in the evaluation of potential osteomalacia patients; (2) PTH offered no apparent benefit as a screening test in our patients; (3) 1,25-(OH)2D3 was low in three patients with normal levels of 25-(OH)D3; (4) decreased urinary calcium excretion had low sensitivity for detecting osteomalacia; and (5) serum calcium, phosphate, alkaline phosphatase, and radiographic examination may be adequate screening tests in patients who have a clinical presentation suggestive of osteomalacia.

Alkaline Phosphatase↗
PubMed1993

Detection of subtle aluminum-related renal osteodystrophy.

We compared the sensitivity of aurin tricarboxylic acid (ATA) or acid solochrome azurine (ASA) for detecting bone aluminum histochemically in 87 biopsy specimens obtained between 1983 and 1987 from 84 patients receiving dialysis therapy. Two consecutive biopsy sections were stained, one with ATA and the other with ASA, and then interpreted independently by two experienced observers. Three groups were established: group 1 (N = 61) had positive results of both ATA and ASA staining, group 2 (N = 25) had negative ATA but positive ASA sections, and group 3 (N = 1) had negative results of both ATA and ASA. No significant differences existed between groups 1 and 2 for age of the patients or serum calcium or immunoreactive parathyroid hormone levels. Patients in group 1 had significantly higher bone aluminium content (110 versus 61 micrograms/g dry ash weight), higher serum aluminum levels (151 versus 26 ng/ml), and longer duration of dialysis (85 versus 30 months) than did patients in group 2. Bone biopsy diagnoses (group 1 versus group 2) included low-turnover bone disease, 8 versus 7; osteomalacia, 26 versus 0; mixed uremic bone disease, 10 versus 1; hyperparathyroidism, 12 versus 14; and mild uremic bone disease, 5 versus 4. On the basis of ATA staining, 7 of 15 patients with low-turnover and 1 of 11 patients with mixed uremic bone disease may have been incorrectly diagnosed as having non-aluminum-related bone disorders. The levels of bone and serum aluminum were lower in group 2 than in group 1 but still much higher than normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗