Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new, highly sensitive radioreceptor assay, which does not require high-performance liquid chromatography, has been developed for the determination of 1,25-dihydroxyvitamin D3 (1,25-(OH2)D3) in serum. The assay involves rapid extraction of serum, Sep Pak silica purification, and addition of 1,25-dihydroxyvitamin D3 receptor, radiolabeled 1,25-dihydroxyvitamin D3, bovine serum albumin, and monoclonal antibody to specifically precipitate the receptor. This method is sensitive to 0.3-0.6 pg/tube, with B50 occurring at 5.8 pg/tube. This sensitivity combined with overall recovery of 1,25-dihydroxyvitamin D3 (81.5 +/- 5.2%, n = 50, mean +/- SD) allows the measurement of serum 1,25-(OH)2D3 in duplicates with only 0.5 ml of serum. Intra- and interassay coefficient of variation were 9.5 and 14.6%, respectively. Dilution analysis, analytical recovery of added 1,25-dihydroxyvitamin D3, and comparison with a standard method using HPLC have been used to validate the assay. Serum 1,25-dihydroxyvitamin D3 level was for normal adults, 36.6 +/- 10.5 pg/ml (n = 14); in primary hyperparathyroidism, 98.9 +/- 19.9 pg/ml (n = 16); in chronic renal failure, 17.8 +/- 5.1 pg/ml (n = 12). This method allows large numbers of samples to be processed at once. Further, the method is rapid and provides an accurate assay using small amounts of serum.
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PMID:A new, highly sensitive assay for 1,25-dihydroxyvitamin D not requiring high-performance liquid chromatography: application of monoclonal antibody against vitamin D receptor to radioreceptor assay. 133 39

Psychiatric disturbances are common in primary hyperparathyroidism (HPT), but their pathogenesis is essentially unknown. This study deals with cerebrospinal fluid (CSF) calcium homeostasis and its connection with parathyroid hormone (PTH), blood-brain barrier (BBB) function, and central monoamine and purine metabolites in patients with primary HPT. In 22 patients with primary HPT (serum calcium 2.85 +/- 0.21 mmol/l), the CSF concentrations of total and ionized calcium were higher (1.21 +/- 0.08 mmol/l, p less than 0.01, and 1.09 +/- 0.05 mmol/l, p less than 0.001, respectively) than in 11 normocalcemic reference subjects. The values correlated with serum calcium concentration (p less than 0.001) and CSF/serum albumin ratio, a measure of BBB permeability. The latter ratio was elevated in one-third of the patients with HPT, indicating BBB damage. CSF immunoreactive intact PTH was higher in the HPT patients than in the reference group (p less than 0.05), and serum and CSF PTH were positively correlated (p less than 0.05). The CSF levels of the monoamine metabolites 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) were lower, and the level of urate in CSF was higher, in the HPT patients than in the reference subjects, while there were no consistent differences in CSF hypoxanthine or xanthine. CSF 5HIAA correlated inversely with CSF ionized calcium (r = -0.42, p = 0.02). After parathyroid surgery, CSF calcium and urate decreased significantly and CSF monoamine metabolites increased slightly. The decrease in CSF ionized calcium correlated with the alleviation of psychiatric symptoms. The results indicate the importance of increased CSF calcium concentrations in patients with primary HPT and suggest a relation between central calcium regulation and central turnover of monoamines.
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PMID:Cerebrospinal fluid calcium, parathyroid hormone, and monoamine and purine metabolites and the blood-brain barrier function in primary hyperparathyroidism. 172 Aug 95

Recursive partitioning analysis was compared to logistic, linear and quadratic discriminant analyses in the ability to differentiate hypercalcemic patients with primary hyperparathyroidism from those with malignancy. Stepwise discriminant analysis identified serum albumin as the best single discriminant test. Albumin decision values optimally separating the two hypercalcemic groups were 39.46, 38.54, and 32.25 g/l for the logistic, linear and quadratic discriminant methods, respectively. Recursive partitioning analysis identified carboxy-terminus parathyroid hormone (PTH) as the best discriminant test with an optimal decision value of 8.2 mequiv/l. The discrepancy between the selection of PTH by recursive partitioning analysis and albumin by discriminant techniques was attributed to the nonnormal distribution of PTH. Recursive partitioning analysis using PTH classified 85.4% of the patients correctly. Logistic, linear and quadratic methods, using albumin as the predictor variable, correctly classified 79.6%, 78.6%, and 79.6% of patients, respectively.
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PMID:Comparison of nonparametric recursive partitioning to parametric discriminant analyses in laboratory differentiation of hypercalcemia. 181 62

The serum concentrations of calcium, albumin and parathyroid hormone (PTH) and the plasma levels of ionized calcium were determined in 124 healthy subjects, 89 patients with primary hyperparathyroidism (HPT), 23 of whom had the syndrome of multiple endocrine neoplasia type 1 (MEN-1) and 43 patients who had hypercalcaemia of other causes than HPT (non-HPT), in most cases due to widespread malignancies. The total serum calcium was corrected for the serum albumin concentration (CaM). Healthy females over the age of 50 had higher CaM, than younger females and the women of all ages also had, higher serum PTH levels than males. For all study groups both the intra- and inter-diurnal variations were small for all the studied variables. Discriminant function and optimal discriminatory limits were calculated with the help of computer programs. A consideration of all the individuals in the discriminant analysis, revealed that measurements of CaM alone separated most HPT patients both from the healthy subjects and from the non-HPT patients. However, when only those who had borderline values (defined as CaM between 2.45 and 2.75 mmol/l) were included it turned out that measurements of ionized calcium markedly improved the delineation of mild HPT from the healthy subjects and that, in addition, PTH measurements helped to exclude those with non-HPT hypercalcaemia. The optimal discriminatory levels of serum calcium were calculated as the levels which caused the minimum loss in terms of misclassification when attention was paid to the relative importance of false positive to false negative classifications and to the prevalence of HPT. The optimal discriminatory level for serum calcium for a weighting ratio between false positive to false negative of 1:1, and a prevalence of HPT of 1%, was calculated to be 2.68 mmol/l and for a prevalence of 50% 2.56 mmol/l. In the latter situation a weighting ratio of 10:1 for false positive to false negative gave a level of 2.63 mmol/l while a weighting ratio of 1:10 corresponded to an optimal discriminatory level of 2.47 mmol/l.
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PMID:Optimal discrimination of mild hyperparathyroidism with total serum calcium, ionized calcium and parathyroid hormone measurements. 288 82

Logistic, linear, and quadratic discriminant analyses were compared in their ability to differentiate hypercalcemic patients with primary hyperparathyroidism from those with malignancy. Linear and quadratic discriminant analyses were performed by use of both untransformed and logarithmically transformed data. Application of principal components analysis with varimax rotation was helpful in revealing the underlying relationships between variables. All discriminant methods identified serum albumin as the best single discriminating test, with the log-quadratic discriminant analysis classifying 81% of patients correctly. The combination of albumin, carboxy-terminal parathyroid hormone, and chloride improved classification accuracy (92% by use of log-quadratic discriminant analysis). Logistic discriminant analysis, using all 20 variables, gave a classification accuracy of 100%. Quadratic discriminant analysis gave better classification than linear discriminant analysis, and both methods performed better when log-transformed data were used. Logistic discriminant analysis followed by discrimination procedures using log-transformed data yielded the highest classification accuracy and reliability of the methods used.
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PMID:Comparison of discriminant analysis procedures in laboratory differentiation of hypercalcemia. 336 66

We describe a radioimmunoassay for 1,25-dihydroxycholecalciferol in human serum. We raised antisera in rabbits to 1,25-dihydroxycholecalciferol-3-hemisuccinate coupled to bovine serum albumin, and obtained sensitive, high-titer antibodies. These antibodies had a high affinity for 1,25-dihydroxycholecalciferol and cross reacted mainly with 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol. Addition of 1 mL of normal rabbit serum per liter reduced this interference to 5 and 4%, respectively. However, these interfering steroids are present in large excess, so extensive purification of 1,25-dihydroxycholecalciferol from serum is necessary. The steroid was extracted with ethyl acetate/cyclohexane, purified on Sephadex LH-20, and then chromatographed on a column of silicic acid. The radioimmunoassay is sensitive to 5 pg/tube (3 ng/L of serum). The between-assay CV was 14%. The mean concentration of 1,25-dihydroxycholecalciferol in the serum of 54 healthy adults was 38 (SD 12) ng/L, with no sex-related difference. The assay was further validated by the finding of low or undetectable concentrations in patients with chronic renal failure and of increased concentrations in the serum of patients with primary hyperparathyroidism. In comparison with previously described methods, the major advantage of the present assay is the use of stable gamma-globulins, which are available in large amounts, as binding protein.
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PMID:A radioimmunoassay for 1,25-dihydroxycholecalciferol. 689 88

Serum PRL, parathyroid hormone (PTH), and Ca levels were measured in 14 patients (8 women and 6 men) with primary hyperparathyroidism. Six normal volunteers (3 men and 3 women) received a 1-h control infusion of 5% glucose containing 2% human serum albumin, a 1-h infusion of the same fluid containing 450 U bovine PTH, and a repeated 1-h infusion of glucose and albumin. Serum PRL was measured during these infusion periods and showed a peak within 30 min of the start of bovine PTH infusion; PRL levels declined therafter in spite of continued PTH infusion. Serum PRL levels returned to normal within 1 h of discontinuance of bovine PTH infusion. The serum PRL levels in patients with primary hyperparathyroidism were within the normal range, and there was no correlation between serum PTH and PRL levels. These results suggest that the PRL response to PTH infusion is a pharmacological rather than a physiological or pathophysiological effect of PTH.
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PMID:Effects of parathyroid hormone infusion and primary hyperparathyroidism on serum prolactin in man. 740 Mar 4

The investigation of hypercalcemia is carried out routinely in our laboratory to detect primary hyperparathyroidism (PHPT). In a retrospective study, seven patients with PHPT and fifty-one patients with non-parathyroid hypercalcemia (NPHC) were chosen in a particular year. To obtain a screening index for PHPT, discriminant analysis, using a stepwise variable select method, was applied to eight biochemical parameters in these patients. A discriminant function (F1) was derived from three biochemical parameters and then another discriminant function (F2) was also derived from three biochemical parameters in the F1-positive patients. In combination of these two functions (F1 and F2), the final sensitivity was 100% and specificity was 98% in diagnosing PHPT. This screening method was tested prospectively in fifty-six consecutive specimens of hypercalcemia (PHPT 4, NPHC 52) over the following six months. The result was also satisfactory with a sensitivity of 100% and specificity of 98%. It was proven that our screening method using discriminant functions (F1 and F2) was very useful for diagnosing patients with PHPT from the survey of hypercalcemia. Among these patients with hypercalcemia, the high ratio (54%) of those with malignancy was remarkable. This interesting result required us to investigate potential hypercalcemia, since the serum calcium concentration was masked by a lower level of serum albumin, which was frequently seen in these malignant patients. As the next step, we tried to adjust the serum calcium concentration based on the serum albumin concentration. A formula for adjusting the calcium concentration was derived from a linear structural relationship between calcium and albumin in 6,821 specimens within a +/- 2.5 second principal component score in 7,021 consecutive specimens in whom both calcium and albumin were measured in a particular year; Adjusted Calcium = Calcium - Albumin + 4. After adjustment using this formula, the calcium concentrations were elevated above the upper limit of the reference interval in 320 of 5,203 specimens (6%) within the reference interval and elevated to the reference interval in 1,390 of 1,579 specimens (88%) below a lower limit of reference interval. A prospective study was performed over the following three months. Fifty patients with hypercalcemia were screened using this formula. It was a surprise that thirty-one patients (62%) showed abnormal values after adjustment. These results suggest that calcium adjustment is necessary for interpreting the calcium concentration of patients with a reduced albumin concentration such as patients with malignancy.
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PMID:[Approach to examining hypercalcemia in the clinical laboratory]. 1063 24

The etiology, pathophysiology, and diagnosis of hypercalcemia associated with malignant diseases are discussed. In humans, calcium is controlled by three mechanisms: parathyroid hormone, which regulates bone resorption and renal reabsorption of calcium; calcitonin, an antagonist of parathyroid hormone; and cholecalciferol, which regulates calcium absorption from the gastrointestinal tract. Hypercalcemia of malignancy (HCM) results primarily from increased bone resorption by osteoclasts and, to a lesser extent, from increased renal tubular reabsorption. In most tumors, parathyroid hormone-related protein (PTHrP) is the primary mediator of calcium. PTHrP stimulates increased bone resorption by osteoclasts. This stimulation also activates transforming growth factor-beta (TGF-beta), which stimulates tumor cells, thus perpetuating the cycle. Hypercalcemia is usually defined as a serum calcium concentration greater than 12 mg/dL, corrected for the serum albumin concentration. In diagnosing HCM, it is important to rule out other causes of hypercalcemia, such as primary hyperparathyroidism.
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PMID:Overview of hypercalcemia of malignancy. 1175 5

A 50-year-old woman presented with pain and tenderness in the right flank. Urogram and ultrasound demonstrated the presence of an 8-mm calculus in the right kidney. There were persistently elevated serum calcium levels ranging from 10.7-11.4 mg/dL (normal range: 8.5-10.5) and borderline low serum phosphate levels of 2.4-2.9 mg/dL (normal range 2.5-4.5). Serum albumin levels were normal. The patient's parathormone levels were elevated and a diagnosis of primary hyperparathyroidism was made. An MRI of the neck failed to reveal evidence of parathyroid pathology. Tc-99m sestamibi imaging demonstrated no abnormal parathyroid tissue in the neck, but clearly showed an abnormal focus in the anterior mediastinum.
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PMID:Tc-99m sestamibi localization of an ectopic mediastinal parathyroid tumor in a patient with primary hyperparathyroidism. 1516 92


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