José Gilberto H. Vieira

Screening for macroprolactinaemia and pituitary imaging studies

objective Hyperprolactinaemia is caused by high levels of monomeric, dimeric or macro forms of prolactin in circulation, the monomeric form being predominant in patients with prolactinomas. Macroprolactinaemia, however, is common and is associated with asymptomatic cases. In this study, we reviewed our records regarding clinical and imaging investigations in patients who were found to have hyperprolactinaemia predominantly due to the presence of macroprolactin and compared them with the findings observed in patients whose prolactin molecular size consisted predominantly of the monomeric form.

Simultaneous quantitation of seven endogenous C-21 adrenal steroids by liquid chromatography tandem mass spectrometry in human serum

Quantitation of endogenous steroids is important in the diagnosis of several endocrine disorders. In this study we present a new method for simultaneous quantitation of cortisol, cortisone, 11-desoxycortisol, 21-desoxycortisol, corticosterone, 17-hydroxyprogesterone and 11-desoxycorticosterone in human serum by on-line extraction and LC-MS/MS. Analytes extraction was performed on-line using a 2-position and 6-port valve equipped with a monolithic silica cartridge. After chromatographic separation of all analytes, detection was performed in the multiple reaction monitoring mode using positive atmospheric pressure chemical ionization mode. Total imprecision of the assay ranged from 5.5 to 15.5%. Comparison with immunoassays yielded coefficients of 0.893 for cortisol, 0.848 for 11-desoxycortisol and 0.924 for 17-hydroxyprogesterone. The sensitivity of this method provides meaningful data for patients within normal and elevated range and it may be useful for the diagnosis of a variety of adrenal dysfunctions.

Osteopenia occurs in a minority of patients with acromegaly and is predominant in the spine.

Acromegaly may induce abnormalities in bone metabolism; however, there are limited data related to bone mineral density (BMD) in this condition. To evaluate the effects of an excess of growth hormone/ insulin-like growth fractor I (GH/IGF-I) in the skeleton, we measured the BMD in spine and femoral region, total body calcium and body composition in 45 patients (24 females and 21 males) aged 21–77 years (median 43 years) with acromegaly for 11.4+7.5 years (range 0.5–26 years) using a dual-energy X-ray absorptiometer (Lunar DPX). Thirty-four patients had had hypogonad-ism for 8.6+6.5 years (1–24 years). Mean serum GH and IGF-I levels were respectively 159±183 µg/1 and 843±497 jig/1. Total body calcium was increased in the acromegalics (males: 1272±217 g, range 916–1816 g; females: 1041±223 g, range 739–1609 g) when compared with normal individuals (males: 1115±144 g, range 856–1398 g; females: 909±144 g, range 511–1311 g;p=0.01). The lean body mass was significantly higher in acromegalic patients(p<0.001) compared with normal individuals. There was a tendency for a lower fat percentage in the acromegalics; however, this difference was not significant. Osteopenia (1Z-score below the mean) was found in the spine in 20% (n=9) of the patients, while BMD was decreased in the femoral region in only 8.8% (n=4). The group with osteopenia had a greater duration of hypogonadism than the normal BMD group (14±11 years vs 4.4±4.0 years;p=0.01). A negative correlation was also found between the duration of hypogonadism and BMD in spine (r=−0.4;p=0.003) and femoral region (r=−0.37;p=0.013). The hypogonadal patients had a lower BMD in spine (p<0.005), but not in other regions analyzed. No correlation was found between duration of hypersomato-tropism, GH/IGF-I levels and BMD. We conclude that the majority of patients with acromegaly have preserved BMD despite the presence of hypogonadism.

Insulin resistance index (HOMA-IR) in the differentiation of patients with non-alcoholic fatty liver disease and healthy individuals

CONTEXT Due to its good correlation to glycemic clamp, HOMA-IR has been widely utilized as insulin resistance index in clinical and epidemiological studies involving non-alcoholic fatty liver disease carriers. However, values used for this parameter have shown large variability. OBJECTIVE To identify the HOMA-IR cut value that best distinguishes non-diabetic non-alcoholic fatty liver disease patients from a control group. METHODS One hundred sixteen non-alcoholic fatty liver disease patients were studied, diagnosed by clinical, biochemical, and liver image or biopsy criteria, and 88 healthy individuals, without any liver disease and testing for oral glucose tolerance within normality. These groups did not differ in age and gender. All were submitted to oral glucose tolerance test and blood samples were collected for glucose and insulin measurements by immunofluorometric method. HOMA-IR was calculated according to the formula: fasting insulin (microU/L) x fasting glucose (nmol/L)/22.5. RESULTS NAFLD patients showed higher insulin, glycemia, and HOMA-IR values than control group, even when excluding glucose intolerant and diabetes mellitus patients by their glycemic curves. HOMA-IR 75th percentile for control group was 1.78 and the best area under the curve index was obtained for HOMA-IR values of 2.0 [AUC= 0.840 (0.781-0.899 CI 95%), sensitivity (Se): 85%, specificity (Sp): 83%] while value 2.5 showed best specificity without important loss in sensitivity [AUC=0,831 (0.773-0.888) Se = 72%, Sp = 94%]. CONCLUSION HOMA-IR values above or equal to 2.0 or 2.5 show enhanced diagnostic value in distinguishing non-alcoholic fatty liver disease carriers from control group individuals.

Prospective bone mineral density evaluation in patients with insulin-dependent diabetes mellitus

The bone mineral density (BMD) in patients with insulin-dependent diabetes mellitus (IDDM) was evaluated prospectively to assess the course of osteopenia in IDDM. We measured BMD in the lumbar spine, femoral region, and total body calcium in 23 patients aged 21-53 years with IDDM for 2.3 to 20 years using a dual energy X-ray absorptiometry. A second BMD measurement was done after 26.5+/-4.1 months in all patients. The blood glucose control, insulin dosage, and disease duration were also assessed. Eleven patients had osteopenia (1 Z-score below the mean values of normal gender- and age-matched individuals). These patients had a longer IDDM duration (8.6+/-5.1 years in osteopenics versus 4.6+/-3.75 years in non-osteopenics; p=0.03). The blood glucose control and insulin dosage were not significantly different throughout the study. The mean spinal BMD was higher in the second evaluation in both osteopenics (0.91+/-0.12 g/cm2 and 0.96+/-0.09 g/cm2, p=0.035) and non-osteopenics (1.24+/-0.15 g/cm2 and 1.29+/-0.16 g/cm2; p=0.02). In the end of the study, however, the osteopenic group persisted with lower subnormal BMD values than the non-osteopenic group (p < 0.001). The small BMD increment observed in the spine did not correlate with changes in the metabolic control or with IDDM duration, but occurred mainly in patients younger than 30 years old. There was no significant change in the femoral BMD or total body calcium. None of the patients developed or significantly worsened the osteopenia. We conclude that diabetic osteopenia, despite being a complication of high prevalence in IDDM, seems to be non-progressive in the majority of patients. In some patients, the spinal BMD increased during observation and may have been due to achievement of peak bone mass.

Y‐chromosome identification by PCR and gonadal histopathology in Turner's syndrome without overt Y‐mosaicism

The frequency of gonadoblastoma is high in patients with Turners syndrome bearing cells with Y or partial Y‐chromosome. About 60% of patients with Turners syndrome have a 45,X karyotype. In 30% of them a Y‐sequence is disclosed by DNA analysis. To identify patients at risk of developing gonadoblastoma, a PCR based assay with SRY, ZFY and DYZ3 specific primers was carried out to detect different Y‐sequences in the DNA of peripheral lymphocytes from patients with Turners syndrome.

Egg yolk as a source of antibodies for human parathyroid hormone (hPTH) radioimmunoassay

Chickens were immunized with synthetic hPTH peptides 1-34 and 53-84. Serum from the best responder of each group was compared with IgG obtained from yolk of eggs layed by the same chicken, showing similar properties. A simple method for purification of IgG from yolk is described, allowing the obtaining of substantial amounts of anti-hPTH IgG without the need for bleeding the animals. We conclude that: 1) egg from chickens immunized with synthetic hPTH peptides are a convenient source of antibodies against these peptides; 2) this principle should apply to any other antigen to which chickens are good responders.

Adipokine Profile and Urinary Albumin Excretion in Isolated Growth Hormone Deficiency

BACKGROUND GH deficiency (GHD) is often associated with cardiovascular risk factors, including abdominal fat accumulation, hypercholesterolemia, and increased C-reactive protein. Despite the presence of these risk factors, adults with congenital lifetime isolated GHD (IGHD) due to an inactivating mutation in the GHRH receptor gene do not have premature atherosclerosis. OBJECTIVE The aim was to study the serum levels of adiponectin and leptin (antiatherogenic and atherogenic adipokine, respectively), and the urinary albumin excretion (UAE) in these IGHD individuals. DESIGN AND PATIENTS We conducted a cross-sectional study of 20 IGHD individuals (seven males; age, 50.8 +/- 14.6 yr) and 22 control subjects (eight males; age, 49.9 +/- 11.5 yr). MAIN OUTCOME MEASURES Anthropometric factors, body composition, blood pressure, serum adiponectin, leptin, and UAE were measured. RESULTS Adiponectin was higher [12.8 (7.1) vs. 9.7 (5) ng/ml; P = 0.041] in IGHD subjects, whereas no difference was observed in leptin [7.3 (6.3) vs. 9.3 (18.7 ng/ml] and UAE [8.6 (13.8) vs. 8.5 (11.1) microg/min]. CONCLUSIONS Subjects with lifetime untreated IGHD have an adipokine profile with high adiponectin and normal leptin levels that may delay vascular damage and lesions of the renal endothelium.

Vitamin D receptor alleles and bone mineral density in a normal premenopausal Brazilian female population

Studies on the association between vitamin D receptor (VDR) polymorphism and bone mineral density (BMD) in different populations have produced conflicting results probably due to ethnic differences in the populations studied. The Brazilian population is characterized by a very broad genetic background and a high degree of miscegenation. Of an initial group of 164, we studied 127 women from the city of São Paulo, aged 20 to 47 years (median, 31 years), with normal menses, a normal diet and no history of diseases or use of any medication that could alter BMD. VDR genotype was assessed by PCR amplification followed by BsmI digestion of DNA isolated from peripheral leukocytes. BMD was measured using dual energy X-ray absorptiometry (Lunar DPX) at the lumbar site (L2-L4) and femoral neck. Most of the women (77.6%) were considered to be of predominantly European ancestry (20.6% of them reported also native American ancestry), 12.8% were of African-Brazilian ancestry and 9.6% of Asian ancestry, 41.0% (52) were classified as bb, 48.8% (62) as Bb and 10.2% (13) as BB. The BB, Bb and bb groups did not differ in age, height, weight, body mass index or age at menarche. Lumbar spine BMD was significantly higher in the bb group (1.22 +/- 0.16 g/cm2) than in the BB group (1.08 +/- 0.14; P < 0.05), and the Bb group presented an intermediate value (1.17 +/- 0.15). Femoral neck BMD was higher in the bb group (0.99 +/- 0.11 g/cm2) compared to Bb (0.93 +/- 0.12) and BB (0.90 +/- 0.09) (P < 0.05). These data indicate that there is a significant correlation between the VDR BsmI genotype and BMD in healthy Brazilian premenopausal females.

Superior discriminating value of ACTH‐stimulated serum 21‐deoxycortisol in identifying heterozygote carriers for 21‐hydroxylase deficiency

Background  Congenital adrenal hyperplasia caused by classic 21‐hydroxylase deficiency (21OHD) is an autosomal recessive disorder with a high prevalence of asymptomatic heterozygote carriers (HTZ) in the general population, making case detection desirable by routine methodology. HTZ for classic and nonclassic (NC) forms have basal and ACTH‐stimulated values of 17‐hydroxyprogesterone (17OHP) that fail to discriminate them from the general population. 21‐Deoxycortisol (21DF), an 11‐hydroxylated derivative of 17OHP, is an alternative approach to identify 21OHD HTZ.