Two-site Immunoradiometric Assay Research Articles

The relationship between serum leptin, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels and clinical parameters in primary fibromyalgia patients.

The aim of this study was to investigate the levels of leptin, growth hormone, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 and their relations with clinical parameters in patients with primary fibromyalgia and healthy controls. Our study was performed on 30 female patients with primary fibromyalgia and 30 healthy controls. The levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 were measured by a two-site immunoradiometric assay. The serum level of leptin was measured by the ELISA kit. The serum level of leptin was significantly higher, but the serum levels of insulin-like growth factor-1 were significantly lower in patients with fibromyalgia syndrome than healthy controls (p<0.001). The leptin level was positively correlated with the Visual Analog Scale, Fibromyalgia Impact Questionnaire score, Beck Depression Inventory score, tender point count, age, and duration of disease (p<0.001), but it was negatively correlated with insulin-like growth factor-1 (p<0.001). The insulin-like growth factor-1 level was negatively correlated with age, Visual Analog Scale, Fibromyalgia Impact Questionnaire and Beck Depression Inventory scores, duration of disease, and tender point count (p<0.001). Our results indicate that high levels of serum leptin and low levels of serum insulin-like growth factor-1 may play a role in the physiopathogenesis of fibromyalgia and may be related to some symptoms.

Maternal vitamin D levels correlate with fetal weight and bone metabolism during pregnancy: a materno-neonatal analysis of bone metabolism parameters.

Vitamin D plays an essential role in neonatal skeletal development and maternal weight gain during pregnancy. We aim to study the association between vitamin D status, maternal weight, and materno-neonatal bone metabolism parameters. From January to June 2017, we conducted this cross-sectional study among 103 pregnant women (21-42 years old) and their singletons. The levels of serum 25-(OH)D, PTH, P1NP, OC, and CTX were measured for mothers andneonates (cord blood). Serum vitamin D and OC weremeasured using chemiluminescence and two-site immunoradiometric assay, respectively. Meanwhile, P1NP, CTX, and PTH were measured by ELISA. The average serum vitamin D levels from mothers were 15.1ng/mL during pregnancy and 16.2ng/mL in the umbilical cord. At baseline, vitamin D deficient mothers were more likely to have higher PTH (36.4 vs. 18pg/mL; p=0.029) and lower P1NP levels (90 vs. 92.5ng/mL; p=0.026). Also, vitamin D deficient status was associated with lower fetal weight (3,293 vs. 3,358 g; p=0.019). Maternal weight was significantly correlated with P1NP (65.86 vs. 109.35; p=0.001) and OC (14.52 vs. 18.24; p=0.038), as well as cord vitamin D level (13.31 vs. 18.46; p=0.039) among normal vs. overweight women. No significant differences were found for the correlation between maternal weight and fetal parameters except for fetal weight which significantly increased with the increase in maternal weight (overweight vs. obese women=3,280 vs. 3,560; p=0.06). Maternal vitamin D status is associated with maternal and neonatal bone metabolism parameters as well as maternal and neonatal weight.

Gender-Dependent Reference Range of Serum Calcitonin Levels in Healthy Korean Adults.

BackgroundSerum calcitonin measurement contains various clinical and methodological aspects. Its reference level is wide and unclear despite sensitive calcitonin kits are available. This study aimed to identify the specific reference range in the healthy Korean adults.MethodsSubjects were ≥20 years with available calcitonin (measured by a two-site immunoradiometric assay) data by a routine health checkup. Three groups were defined as all eligible subjects (group 1, n=10,566); subjects without self or family history of thyroid disease (group 2, n=5,152); and subjects without chronic kidney disease, autoimmune thyroid disease, medication of proton pump inhibitor/H2 blocker/steroid, or other malignancies (group 3, n=4,638).ResultsThis study included 6,341 male and 4,225 female subjects. Males had higher mean calcitonin than females (2.3 pg/mL vs. 1.9 pg/mL, P<0.001) in group 1. This gender difference remained similar in groups 2 and 3. Calcitonin according to age or body mass index was not significant in both genders. Higher calcitonin in smoking than nonsmoking men was observed but not in women. Sixty-nine subjects had calcitonin higher than the upper reference limit (10 pg/mL) and 64 of them had factors associated with hypercalcitoninemia besides medullary thyroid cancer. Our study suggests the reference intervals for men who were non, ex-, current smokers, and women (irrespective of smoking status) as <5.7, <7.1, <7.9, and <3.6 pg/mL, respectively.ConclusionSpecific calcitonin reference range should be provided considering for sex and smoking status. Taking account for several factors known to induce hypercalcitoninemia can help interpret the gray zone of moderately elevated calcitonin.

Free/Total Serum Prostate-Specific Antigen Ratio in Women with Colorectal Cancer Has Prognostic Significance.

The presence of prostate-specific antigen (PSA) in colon cancer tissues has been shown, but its clinical significance has not been known yet in colorectal cancer patients. We investigated the prognostic significance of percent free PSA value (free PSA/total PSA×100) in female patients with colorectal cancer. The serum concentrations of total and free PSA were measured by solid-phase two-site immunoradiometric assay in 184 patients. The cancer-specific survival (CSS) of patients with percent free PSA value ≥35 was significantly better compared to that of patients with percent free PSA value <35 (CSS rate was 82.9 and 55.5%, respectively; log-rank x2=8135, p=0.004). In multivariate Cox analysis, this percent free PSA threshold value had independent prognostic significance (relative risk 0.27, 95% confidence interval 0.11-0.64, p=0.003). Percent free PSA value, calculated by serum total and free PSA levels, has prognostic significance in women with colorectal cancer. The studies with larger patient series, utilizing ultrasensitive PSA assays whose lowest detection limit is lower, are required for a clearer understanding of this issue.

The impact of intrauterine infection on fetal brain damage assessed by S100B protein concentrations in umbilical cord arteries

Objective: To assess the impact of intrauterine infection on fetal brain damage by measuring S100B protein concentration in umbilical cord arteries. Methods: In the intrauterine infection cases determined by pathology of 25 deliveries (Group I) and non-infection cases of 35 deliveries as control (Group C), we compared gestational age at delivery, birth weight, fetal heart rate monitoring during labor, Apgar score, umbilical cord artery pH and S100B protein concentrations in umbilical arteries measured by two-site immunoradiometric assay kit. Results: (1) There was no significant correlation between pH and concentration of S100B protein. (2) Gestational age at delivery was found to be earlier in Group I, resulting in lower birth weights, when compared with Group C. (3) There was no significant difference between two groups concerning Apgar scores, pH. (4) S100B protein concentrations in Group I was significantly higher than those of Group C (3.9 7 ± 0.66 versus 1.8 9 ± 0.56 μg/L, p < 0.05). (5) The concentration of S100B protein in severe chorioamnionitis (CAM) cases were significantly higher than those of mild CAM and control cases. Conclusion: Higher concentration of S100B protein in Group I suggests that intrauterine infection itself has a serious risk factor on fetal brain damage.

Effects of simvastatin on human breast cancer osteolytic bone metastasis in a nude mice model

Objective To observe the effect of simvastatin on bone metastasis of breast cancer in nude mice model. Methods Sixty mice were divided into three groups randomly with 20 in each group. Mice were inoculated with MDA-MB-231 cells into the left cardiac ventricle. After 7 days, mice were treated with either simvastatin, saline, or nothing twice per week for 19 days. The area of osteolytic metastases was subsequently measured in long bones of all mice using an image analysis system. After sacrifice, parathyroid hormone-related protein (PTHrP) concentrations in bone marrow from all mice were determined using a two-site immunoradiometric assay. Osteoclast number expressed per millimeter of tumor/bone interface was assessed using an OsteoMeasure System. Measured data were compared with analysis of variance, and P<0.05 for the difference was statistically significant. Results The area of osteolytic lesions was significantly lower in mice treated with simvastatin compared with mice receiving saline and no treatment (0.51±0.18 mm2vs 2.13±1.24 mm2vs 2.29±1.22 mm2;F=15.600, P=0.002; F=15.673, P=0.001). In addition, treatment with simvastatin decreased the concentrations of PTHrP in bone marrow plasma (0.98±0.20 pmol/L vs 2.11±0.31 pmol/L vs 1.99±0.29 pmol/L; F=61.469, P<0.001; F=58.274, P<0.001) and the osteoclast numbers per millimeter of tumor/bone interface (4.00±1.73 vs 11.40±4.93 vs 10.91±3.87; F=17.820, P=0.001; F=17.184, P=0.002) compared with controls. Conclusion Simvastatin may reduce the production of PTHrP of breast cancer cells, which suppresses the development of destructive bone lesions as well as the growth of breast cancer cells in bone. Key words: Breast neoplasms; Neoplasm metastasis; Simvastatin; Parathyroid hormone

A Giant Ovarian Cyst in a Neonate with Classical 21-Hydroxylase Deficiency with Very High Testosterone Levels Demonstrating a High-Dose Hook Effect

Congenital adrenal hyperplasia (CAH) is a group of disorders affecting the adrenal steroid synthesis. The most common form, 21-hydroxylase deficiency (21-OHD), leads to decreased production of cortisol and aldosterone with increased androgen secretion. In classic CAH, glucocorticoid treatment can be life-saving and serves to bring the symptoms under control. However, the treatment challenge is to effectively control the excess androgen effect by using the lowest possible glucocorticoid dose. Previous studies suggested a relationship between ovarian cyst formation and adrenal androgen excess, but neonatal large ovarian cysts have been very rarely reported in newborns with CAH. Here, we present the unique case of a neonate with classical 21-OHD who underwent surgery for a giant (10x8x7 cm) unilateral solitary ovarian follicular cyst on the 2nd postnatal day. Hormonal evaluation of the patient revealed high-dose hook effect for serum testosterone levels for the first time by a two-site immunoradiometric assay. Possible mechanisms by which androgen excess may cause ovarian cyst formation are discussed. Conflict of interest:None declared.

Prostate Specific Antigen in Cord Blood

Recent studies have demonstrated the presence of prostate specific antigen (PSA) in cord blood of male as well as female babies. The placental progesterone and estradiol up-regulate the synthesis and secretion of PSA in Placenta. This PSA is presumed to play a role in intrauterine growth of fetus by virtue of its proteolytic action on several substrates including insulin-like-growth-factor-binding-protein-3, insulin chains and Interleukin-2. This study was planned with the objective of correlating the levels of PSA in cord blood to gestation at delivery, the type of delivery and gender of the fetus. Fifty-seven cord blood samples were collected from the umbilical cord during delivery or mid-trimester abortion and analyzed for PSA using 'Active PSA DSL-9700 ultra sensitive' kit employing two-site immuno-radiometric assay principle and having a detection limit of 0.001ng/ml. Mean PSA levels in cord blood were found to be 0.112±0.027ng/ml. The concentration of PSA in cord blood was found to be higher in case of higher gestational age, male baby and operative delivery. 50% of cord bloods for female babies had PSA below detection limit (range <0.001-0.460ng/ml), while all the male samples had detectable PSA (range 0.11-0.973ng/ml). Higher Progesterone levels found in prenatal maternal blood in case of male babies may be responsible for the higher cord blood PSA. Mean cord blood PSA was 0.150±0.150ng/ml in forceps delivery and 0.078±0.012ng/ml in normal vaginal delivery. Forceps delivery causes much more stress and strain as compared to a normal vaginal delivery, resulting in increased levels of adrenal glucocorticoids, and therefore, higher cord blood PSA.

Calciotropic hormones and the risk of hip and nonspine fractures in older adults: The health ABC study

The effects of vitamin D and parathyroid hormone (PTH) levels on incident fracture remain uncertain. To test the hypothesis that increasing serum 25-hydroxyvitamin D [25(OH)D] and decreasing PTH levels are associated with decreased risk of hip and any nonspine fracture, we conducted a prospective cohort study among 2614 community-dwelling white and black participants, aged ≥70 years, from the Health, Aging and Body Composition (Health ABC) Study. Serum and plasma samples were drawn at year 2, which formed the baseline for this analysis. Serum 25(OH)D and intact PTH (1-84) were measured using radioimmunoassay with DiaSorin reagents and EDTA plasma with a two-site immunoradiometric assay kit, respectively. Incident fractures (hip and any nonspine) were assessed after year 2, every 6 months, by self-report and validated by radiology reports. The median (interquartile range) follow-up times for hip and any nonspine fractures were 6.4 (6.1-6.5) and 6.4 (5.5-6.5) years, respectively. Cox proportional hazards regression was used to estimate the hazard ratios (HR) with 95% confidence intervals (CI) for fracture. There were 84 hip and 247 nonspine fractures that occurred over the follow-up period. The multivariable adjusted HRs (95% CIs) of hip fracture for participants in the lowest (≤17.78 ng/mL), second (17.79 to 24.36 ng/mL), and third quartiles (24.37 to 31.94 ng/mL) of 25(OH)D were 1.92 (0.97 to 3.83), 0.75 (0.32 to 1.72) and 1.86 (1.00 to 3.45), respectively, compared with participants in the highest 25(OH)D quartile (>31.94 ng/mL) (p trend = 0.217). Additional adjustment for IL-6 (p = 0.107), PTH (p = 0.124), and hip areal bone mineral density (p = 0.137) attenuated HRs of hip fracture in the lowest quartile by 16.3%, 17.4%, and 26.1%, respectively. There was no evidence of an association between 25(OH)D and any nonspine fractures, or between PTH and hip or any nonspine fractures. We found limited evidence to support an association between calciotropic hormones and hip and nonspine fractures in older men and women.

Changes in Serum Parathyroid Hormone–Related Protein in Breastfed Preterm Infants

Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. In a previous study we have demonstrated high concentrations of PTHrP in both term and preterm human milk (HM). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant have not been studied yet. This study assessed the correlation between PTHrP concentrations in preterm HM and PTHrP in maternal and neonatal serum. We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks of gestation) and drew blood samples from both mothers and infants on postpartum days 2 and 10. PTHrP concentrations were measured by two-site immunoradiometric assay. Blood calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) concentrations were also measured. Neither maternal nor neonatal PTHrP serum concentrations varied significantly after 10 days of breastfeeding. There was a correlation between PTHrP concentrations in maternal serum and HM concentrations (R² = 0.24, p = 0.04), but not between HM and neonatal serum concentrations or between PTHrP concentrations in HM and preterm serum concentrations of Ca, P, and ALP. Despite high concentrations of PTHrP in preterm HM, serum concentrations of PTHrP of breastfed preterm infants did not increase over time. There was no correlation between PTHrP concentrations in HM and neonatal serum Ca concentration.

1027 Parathyroid Hormone Related Protein (PTHRP) in Preterm Human Milk

Background:Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcaemia. In a previous study we demonstrated high levels of PTHrP in both term and preterm human milk (HM) (Breastfeeding Medicine, 2009). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant (PTI) has not been studied yet.Objective: To assess the correlation between PTHrP level in preterm HM and PTHrP in maternal and neonatal serum. Design/Methods: We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks' gestation). In addition, blood samples from both mothers and infants were drawn. All samples were collected at days 2 and 10 postpartum. PTHrP levels were measured by twosite immunoradiometric assay. Blood calcium (Ca), Phosphorus (P) and alkaline phosphatase (ALP) levels were also measured.Results: Both maternal and neonatal PTHrP serum levles did not vary after 10 days of breastfeeding. No correlation was found between PTHrP level in HM and serum PTHrP, Ca, P and ALP of the breastfed PTI.Conclusions: Despite high levels of PTHrP in preterm HM, serum levels of PTHrP of the breast fed PTI do not increase over time. We found no correlation between PTHrP in HM and neonatal Ca serum concentration. We speculate that PTHrP intestinal absorption in the PTI is not significant.

Switching of G-protein Usage by the Calcium-sensing Receptor Reverses Its Effect on Parathyroid Hormone-related Protein Secretion in Normal Versus Malignant Breast Cells

The calcium-sensing receptor (CaR) is a G-protein-coupled receptor that signals in response to extracellular calcium and regulates parathyroid hormone secretion. The CaR is also expressed on normal mammary epithelial cells (MMECs), where it has been shown to inhibit secretion of parathyroid hormone-related protein (PTHrP) and participate in the regulation of calcium and bone metabolism during lactation. In contrast to normal breast cells, the CaR has been reported to stimulate PTHrP production by breast cancer cells. In this study, we confirmed that the CaR inhibits PTHrP production by MMECs but stimulates PTHrP production by Comma-D cells (immortalized murine mammary cells) and MCF-7 human breast cancer cells. We found that changes in intracellular cAMP, but not phospholipase C or MAPK signaling, correlated with the opposing effects of the CaR on PTHrP production. Pharmacologic stimulation of cAMP accumulation increased PTHrP production by normal and transformed breast cells. Inhibition of protein kinase A activity mimicked the effects of CaR activation on inhibiting PTHrP secretion by MMECs and blocked the effects of the CaR on stimulating PTHrP production in Comma-D and MCF-7 cells. We found that the CaR coupled to Galphai in MMECs but coupled to Galphas in Comma-D and MCF-7 cells. Thus, the opposing effects of the CaR on PTHrP production are because of alternate G-protein coupling of the receptor in normal versus transformed breast cells. Because PTHrP contributes to hypercalcemia and bone metastases, switching of G-protein usage by the CaR may contribute to the pathogenesis of breast cancer.

Relationship between Leptin, Insulin Resistance, Insulin-like Growth Factor-1 and Insulin-like Growth Factor Binding Protein-3 in Patients with Chronic Kidney Disease

This study examined the relationship between leptin, insulin-like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3) and insulin resistance in patients with chronic kidney disease (CKD). Levels of leptin, insulin, IGF-1, IGFBP-3 and common routine parameters were measured in 45 patients (23 males and 22 females) with CKD and 45 healthy controls matched for age, gender and body mass index. IGF-1 and IGFBP-3 levels were measured using a two-site immunoradiometric assay. Leptin levels were measured using an enzyme-linked immunosorbent assay. A homeostasis model assessment computer-solved model was used to assess insulin resistance (HOMA-IR). Levels of serum leptin, insulin, IGF-1, IGFBP-3 and HOMA-IR were significantly increased in patients with CKD compared with healthy subjects, whereas fasting blood glucose was not significantly different between the two groups. In patients with CKD, the serum leptin level was significantly correlated with IGF-1, IGFBP-3 and HOMA-IR. In conclusion, this study suggests that there is an interaction between leptin, IGF-1, IGFBP-3 and insulin resistance in patients with CKD.

The Effect of Type of Delivery and Povidone-Iodine Application at Delivery on Cord Dried-Blood-Specimen Thyrotropin Level and the Rate of Hyperthyrotropinemia in Mature and Normal-Birth-Weight Neonates Residing in an Iodine-Replete Area: Report of Tehran Province, 1998–2005

To evaluate the effects of delivery type and of povidone-iodine disinfection at delivery on cord dried-blood-specimen (DBS) thyrotropin (TSH) concentrations. From 1998 to 2005, cord DBSs were collected from live deliveries in Tehran and Damavand, and TSH was assayed by a two-site immunoradiometric assay. Hyperthyrotropinemia was defined as TSH > or =20 mU/L. Vaginal deliveries prepared with povidone-iodine (VGL-PVP-I) or chlorhexidine (VGL-CHL), and cesarean sections prepared with povidone-iodine (CS-PVP-I) disinfection were assessed. Full-term, normal-size newborns were included. Iodine concentrations were measured in urine samples collected from 132 pregnant women immediately prior to delivery. Median (range) TSH was 5.3 (1.0 to >100) mU/L in VGL-PVP-I (n = 23,432), 5.3 (1.0 to >100) mU/L in VGL-CHL (n = 5658), and 5.0 (1.0 to >100) mU/L in CS-PVP-I (n = 19,016) (p < 0.0001). Median TSH was higher in VGL-PVP-I versus CS-PVP-I (p < 0.0001) and in VGL-CHL versus CS-PVP-I (p < 0.0001). Hyperthyrotropinemia was present in 1.4%, 1.2%, and 0.8% of VGL-PVP-I, VGL-CHL, and CS-PVP-I deliveries, respectively, and was significantly higher in VGL-PVP-I versus CS-PVP-I (p < 0.0001) and in VGL-CHL versus CS-PVP-I (p = 0.005). Median (range) urinary iodine concentration of pregnant women was 176 (20-4600) microg/L. Cord DBS TSH and rates of hyperthyrotropinemia are lower in cesarean section than in vaginal deliveries. Povidone-iodine disinfection at delivery has an effect neither on DBS TSH concentrations nor on the rate of hyperthyrotropinemia in the iodine-replete area of Iran.

Maternal plasma corticotropin-releasing factor (CRF) and CRF-binding protein (CRF-BP) levels in post-term pregnancy: effect of prostaglandin administration

Placental corticotropin-releasing factor (CRF) affects myometrial contractility and the secretion of several uterotonins such as prostaglandins (PGs); however, the activity of CRF is counteracted by CRF-binding protein (CRF-BP). At term and pre-term labor, CRF levels in maternal plasma are highest whereas those of CRF-BP are falling, and the cause of this fall is unknown. Thus, in this study, we investigated the effect of PG administration for labor induction on maternal plasma CRF and CRF-BP concentrations. Maternal plasma CRF and CRF-BP levels were assayed before and after (2 h later) induction of labor by intracervical administration of prostaglandin E(2) (PGE(2)), and at delivery in a group of healthy post-term pregnancies (n=18). Controls were women at term out of labor (n=22), who subsequently progressed to deliver a healthy singleton baby. CRF was measured by two-site immunoradiometric assay, and CRF-BP was assayed by radioimmunoassay. Maternal plasma CRF levels were significantly (P<0.0001) lower and CRF-BP significantly (P<0.0005) higher in post-term than in term pregnancies. With respect to induction of labor, 2 mg PGE(2) were sufficient to increase maternal plasma CRF levels at delivery (P<0.005). While 0.5 mg PGE(2) significantly decreased maternal plasma CRF-BP levels at delivery (P<0.001), 2.0 mg PGE(2) significantly reduced CRF-BP concentrations both after 2 h (P<0.05) and at delivery (P<0.0001). In the light of the well-known stimulation of prostaglandin release by CRF, these data suggest a positive feedback effect of PGE(2) on maternal CRF release during induced labor.

Correlation of serum IGF‐I and IGFBP‐1 and ‐3 to cardiovascular risk indicators and early carotid atherosclerosis in healthy middle‐aged men

IGF-I, IGFBP-1 and IGFBP-3 are putative mediators in cardiovascular disease. The present study examined (i) the correlations of circulating IGF-I, IGFBP-1 and IGFBP-3 to established cardiovascular risk factors and signs of early atherosclerosis as reflected by ultrasound measurement of common carotid intima-media thickness (IMT), and (ii) whether serum concentrations of these analytes are modulated during alimentary lipaemia. Cross-sectional clinical study. A biobank and clinical database based on 96 healthy Caucasian men, aged 50 years, with an apolipoprotein (apo) E3/E3 genotype, who had originally undergone investigations of postprandial lipoprotein metabolism was used for the study. Total IGF-I, IGFBP-1 and IGFBP-3 were determined in serum by radioimmunoassay (RIA). Free IGF-I was measured by a commercial two-site immunoradiometric assay (IRMA). In multivariate analyses, fasting serum free IGF-I correlated inversely with IMT and accounted for 5% of the variation in multiple R(2). When fasting serum IGFBP-1 was entered in the models instead of IGF-I, IGFBP-1 correlated positively with IMT and accounted for 6% of the variation in IMT. IGFBP-3 and total IGF-I were unrelated to IMT. There were no associations between free IGF-I and cardiovascular risk factors, whereas IGFBP-1 behaved like a component of the insulin resistance syndrome. Serum free IGF-I increased and IGFBP-1 decreased postprandially. The data indicate that serum free IGF-I and IGFBP-1 are implicated in early atherosclerosis.

Lack of Noggin Expression by Cancer Cells Is a Determinant of the Osteoblast Response in Bone Metastases

Prostate and mammary cancer bone metastases can be osteoblastic or osteolytic, but the mechanisms determining these features are unclear. Bone morphogenetic and Wnt proteins are osteoinductive molecules. Their activity is modulated by antagonists such as noggin and dickkopf-1. Differential expression analysis of bone morphogenetic and Wnt protein antagonists in human prostate and mammary cancer cell lines showed that osteolytic cell lines constitutively express in vitro noggin and dickkopf-1 and at least one of the osteolytic cytokines parathyroid hormone-related protein, colony-stimulating factor-1, and interleukin-8. In contrast, osteoinductive cell lines express neither noggin nor dickkopf-1 nor osteolytic cytokines in vitro. The noggin differential expression profile observed in vitro was confirmed in vivo in prostate cancer cell lines xenografted into bone and in clinical samples of bone metastasis. Forced noggin expression in an osteoinductive prostate cancer cell line abolished the osteoblast response induced in vivo by its intraosseous xenografts. Basal bone resorption and tumor growth kinetics were marginally affected. Lack of noggin and possibly dickkopf-1 expression by cancer cells may be a relevant mechanism contributing to the osteoblast response in bone metastases. Concomitant lack of osteolytic cytokines may be permissive of this effect. Noggin is a candidate drug for the adjuvant therapy of bone metastasis.

Threshold value of serum 25-hydroxyvitamin D concentration in relation to elevated serum parathyroid hormone concentrations in elderly Japanese women

This study was designed to determine the threshold value for 25-hydroxyvitamin D [25(OH)D] concentration in relation to elevated serum parathyroid hormone (PTH) concentrations in elderly Japanese women. The subjects were 582 noninstitutionalized, ambulant women who lived in a community in Japan. Serum 25(OH)D concentrations were determined using the Nichols Advantage chemiluminescent assay, and serum intact PTH concentrations were determined with a two-site immunoradiometric assay. Demographic characteristics, calcium intake, and serum 1,25(OH)(2)D levels were also determined. The average age, body mass index (BMI), and calcium intake of the subjects were 74.5 years (SD 4.5), 23.3 kg/m(2) (SD 3.4), and 579 mg/day (SD 248), respectively. The serum log-transformed intact PTH concentration was significantly predicted by the serum 25(OH)D concentration (r = -0.147, P = 0.0004), but not by age, BMI, the serum log-transformed 1,25(OH)(2)D concentration, or the log-transformed calcium intake. Analysis of variance with Dunnett's multiple comparisons showed that mean serum intact PTH concentrations with serum 25(OH)D concentrations less than 30 nmol/l (mean intact PTH = 5.89 pmol/l, P < 0.0001) and in the range 30-39 nmol/l (mean intact PTH = 4.54 pmol/l, P = 0.0067) were significantly higher than mean intact PTH concentrations for serum 25(OH)D concentrations greater than 50 nmol/l (mean intact PTH = 3.65 pmol/l, the baseline level), but the mean serum intact PTH concentration for 25(OH)D concentrations in the range 40-49 nmol/l (mean intact PTH = 3.70 pmol/l, P = 0.9975) was not. We conclude that serum 25(OH)D for ambulant elderly Japanese women should be maintained at 40 nmol/l or higher.

Inter-method variability in PTH measurement: Implication for the care of CKD patients

The National Kidney Foundation/Kidney-Dialysis Outcome Quality Initiative guidelines recommend to maintain the serum intact parathyroid hormone (PTH) concentration between 150 and 300 ng/l in chronic kidney disease (CKD) stage 5 patients. As these limits were derived from studies that used the Allegro intact PTH assay, we aimed to evaluate whether they were applicable to other PTH assays. We compared the PTH concentrations measured with 15 commercial immunoassays in 47 serum pools from dialysis patients, using the Allegro intact PTH assay as the reference. We also evaluated the recovery of graded amounts of synthetic 1-84 and 7-84 PTH added separately to a serum pool. Although the assays were highly correlated, the concentrations differed from one assay to another. The median bias between the tested assays and the Allegro intact PTH assay ranged from -44.9 to 123.0%. When the PTH concentrations were 150 or 300 ng/l with the Allegro intact PTH assay, they ranged with other assays from 83 to 323 ng/l and from 160 to 638 ng/l, respectively. The tested assays recognized 7-84 PTH with various cross-reactivities, whereas a given amount of 1-84 PTH was recovered differently by these assays. We found important inter-method variability in PTH results owing to both antibody specificity and standardization reasons. The unacceptable consequence is that opposite therapeutic attitudes may be reached in a single patient depending on the PTH assay used. We propose to use assay-specific decision limits for CKD patients, or to apply a correcting factor to the PTH results obtained with a given assay.

Comparative evaluation of a new immunoradiometric assay for corticotropin

We have characterized the performance of a commercial two-site immunoradiometric assay for manual in vitro diagnostic measurement of plasma corticotropin from Scantibodies Laboratory. We compared the results with those of a similar commonly used assay from Nichols Institute Diagnostics that has recently been withdrawn from production. The lower detection limit, range of the standard curve, cross-reactivity, and intra-assay and inter-assay imprecision of the two assays are very similar. Measurement of clinical samples and a series of samples from an experimental subject demonstrate high correlations between the two assays. These factors, together with recent clearance by the United States Food and Drug Administration for manual in vitro diagnostic measurement, make the Scantibodies corticotropin immunoradiometric assay an appropriate replacement for the Nichols assay.