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Biomedical subjects

D Giannella-Neto

Publications and source records attributed to D Giannella-Neto.

At least 19 recordsLinked to original sources
PubMed2006

Metallothionein isoform 3 gene is differentially expressed in corticotropin-producing pituitary adenomas.

In order to search for candidate genes related to pituitary adenoma aggressiveness, the present investigation was intended to compare the mRNA expression profile from a pool of four nonfunctional pituitary adenomas (NFPA) with a spinal cord metastasis of a nonfunctional pituitary carcinoma (MNFPC). The metallothionein isoform 3 (MT3) gene was differentially expressed in nonfunctional adenomas in comparison to the metastasis of nonfunctional carcinoma. A microarray dataset comprising 19,881 probes was employed for comparing expression profiles of a spinal cord metastasis of a nonfunctional pituitary carcinoma with a pool of four nonfunctional pituitary adenomas. RT-qPCR confirmed the microarray findings and was used to investigate MT3 mRNA gene expression in tumor samples of a series of 52 different pituitary adenoma subtypes comprising 10 corticotropin (ACTH)-producing, 18 growth hormone (GH)-producing, 8 prolactin (PRL)-producing, and 16 nonfunctional adenomas. Microarray data analysis by GeneSifter program unveiled Gene Ontology terms related to zinc ion-binding activity closely related to MT3 function. MT3 mRNA expression was statistically significantly higher in ACTH-producing pituitary adenomas and in nonfunctional pituitary adenomas in comparison to the other pituitary adenoma subtypes. The more abundant expression of this gene in ACTH-producing pituitary adenomas suggests that MT3 could be related to distinct pituitary cell lineage regulating the activity of some transcription factor of importance in hormone production and/or secretion.

Adenoma↗
PubMed2006

Endogenous hyperinsulinemic hypoglycemia: diagnostic strategies, predictive features of malignancy and long-term survival.

Diagnostic strategies, malignancy predictors and long-term survival were retrospectively evaluated in patients with hyperinsulinemic hypoglycemia (64 insulinomas). Lower median glycemia was 30 (range 20-53) mg/dl [1.6 (1.1-2.9) mmol/l] with concurrent insulin of 48 (13.2-217) microU/ml and 15 (2-46) microU/ml measured by radioimmunoassay (RIA) and immunofluorimetric assay (IFMA), respectively. All patients with insulinomas had a positive prolonged fast within 48 h. Sensitivity of localization methods was: ultrasonography (US) 23%, computed tomography (CT) 28%, magnetic resonance imaging (MRI) 65%, endoscopic US 75%, arteriography 38%, portal venous sampling 67%, selective arterial calcium stimulation 67%, intraoperative US 94% and palpation 92%. Nine patients (14%) had malignant insulinomas. Age at diagnosis (mean+/-SD, 53.8+/-19 vs 39.4+/-16.3 yr; p=0.03), insulin (1372+/-730 vs 785+/-659% (percentage of the method's diagnostic cut-off; 6 and 3 microU/ml for RIA and IFMA, respectively; p=0.007) and C-peptide levels (9.8+/-2.9 vs 3.9+/-2.8 ng/ml (3.2+/-0.9 vs 1.3+/-0.9 nmol/l; p=0.006), and tumor size (6.2+/-4.1 vs 1.5+/-0.6 cm; p=0.0002) were increased in malignant insulinomas. C-peptide level above 6.1 ng/ml (2.0 nmol/l) had a 100% sensitivity and 96% specificity, and tumor size above 2.6 cm yielded a sensitivity of 88% and specificity of 100% in predicting malignancy. Survival of patients with malignant insulinomas was significantly impaired (16 vs 100% at 5 yr; p=0.0000001). The diagnosis of insulinoma can be made within 48 h of fasting. The association between intraoperative US and palpation evidenced the tumor in 95% of the patients. C-peptide and tumor size were reliable malignancy predictors.

Adolescent↗
PubMed2006

Dissociation between tumor shrinkage and hormonal response during somatostatin analog treatment in an acromegalic patient: preferential expression of somatostatin receptor subtype 3.

INTRODUCTION: About a third of acromegalic patients is resistant to available SS analogs (SA), octreotide (OCT) and lanreotide (LAN). Such resistance is related to reduction of SS receptor (SSTR) density or to a different expression of SSTR subtypes. There are 5 known SSTR subtypes. SSTR2 and SSTR5 are usually expressed in GH-secreting pituitary tumors, and both SA bind preferentially to SSTR2 and, to a lesser extent, to SSTR5. We herein describe an acromegalic patient who presented impressive tumor shrinkage without hormonal normalization during primary therapy with SA. MATERIAL AND METHODS: This 23-yr-old male acromegalic patient was treated with slow-release LAN (LAN-SR), 30 mg every 10 days for six months, followed by OCT-LAR, 30 mg every 28 days for an additional six months with a 75% tumor volume reduction but without GH and IGF-I normalization. Subsequently, he underwent pituitary surgery and expression of SSTR in the removed tumor was performed by real time RT-PCR by the 2-deltaCt method, using GAPDH as internal control. All PCR products were confirmed by automated sequencing. RESULTS: SSTR expression revealed an unusual profile, with almost exclusively expression of SSTR3. CONCLUSIONS: These unusual clinical and receptor subtypes profile suggest an important role of SSTR3 on tumor shrinkage. The low affinity of LAN and OCT for this SSTR subtype could be compensated by its high expression in this GH-secreting pituitary macroadenoma.

Acromegaly↗
PubMed2001

The contribution of 700,000 ORF sequence tags to the definition of the human transcriptome.

Open reading frame expressed sequences tags (ORESTES) differ from conventional ESTs by providing sequence data from the central protein coding portion of transcripts. We generated a total of 696,745 ORESTES sequences from 24 human tissues and used a subset of the data that correspond to a set of 15,095 full-length mRNAs as a means of assessing the efficiency of the strategy and its potential contribution to the definition of the human transcriptome. We estimate that ORESTES sampled over 80% of all highly and moderately expressed, and between 40% and 50% of rarely expressed, human genes. In our most thoroughly sequenced tissue, the breast, the 130,000 ORESTES generated are derived from transcripts from an estimated 70% of all genes expressed in that tissue, with an equally efficient representation of both highly and poorly expressed genes. In this respect, we find that the capacity of the ORESTES strategy both for gene discovery and shotgun transcript sequence generation significantly exceeds that of conventional ESTs. The distribution of ORESTES is such that many human transcripts are now represented by a scaffold of partial sequences distributed along the length of each gene product. The experimental joining of the scaffold components, by reverse transcription-PCR, represents a direct route to transcript finishing that may represent a useful alternative to full-length cDNA cloning.

Expressed Sequence Tags↗
PubMed2001

The insulin-like growth factor-I system and hormone replacement therapy.

OBJECTIVE: To determine the effects of hormone replacement therapy on plasma concentrations of free and total insulin-like growth factor (IGF)-I, IGF binding protein (BP)-1, and IGFBP-3. DESIGN: Clinical study. SETTING: Gynecologic clinic at a university hospital. PATIENT(S): Seventy-one postmenopausal women. INTERVENTION(S): Six cycles of four different hormonal replacement therapy regimens: oral conjugated estrogens, transdermal estradiol, oral conjugated estrogens and norethisterone, and transdermal estradiol and norethisterone acetate. MAIN OUTCOME MEASURE(S): Blood samples were collected before and after treatment for measurement of free and total IGF-I, IGFBP-1, and IGFBP-3. RESULT(S): Conjugated estrogen replacement therapy is associated with a decrease in plasma concentration of total IGF-I and increase in concentrations of free IGF-I and IGFBP-1. Transdermal estrogens have no effect on total and free IGF-I and IGFBP-1 concentrations. Oral norethisterone plus conjugated estrogens increased free IGF-I and IGFBP-1 concentrations but did not change IGF-I concentrations. Transdermal conjugated estrogens plus norethisterone acetate increased free IGF-I concentrations but not total IGF-I or IGFBP-1 concentrations. The plasma concentration of IGFBP-3 did not change in any group. CONCLUSION(S): Alterations in total IGF-I concentration can occur depending on the route of hormone replacement therapy administration. Free IGF-I concentrations were elevated in all study groups except that treated with transdermal estrogens.

Administration, Cutaneous↗
PubMed2001

Interferon-alpha therapy increases type I insulin-like growth factor receptors expression on lymphoid cells from patients with chronic myelogenous leukemia.

Aiming to verify if insulin-like growth factor type I and its receptor (IGF-IR) are implicated on pathophysiology of chronic myelogenous leukemia (CML), we studied 35 patients with CML in chronic phase at diagnosis or during interferon-alpha (IFN-A) or hydroxyurea treatments. Cytometry flow analysis and reverse transcription PCR (RT-PCR) molecular assay for IGF-IR expression on peripheral blood cells from CML patients diagnosed didn't show statistical differences from the control group. Hydroxyurea treated patients had lower expression of IGF-IR in granulocytes, lymphocytes and monocytes (P<0.01). We found statistical higher percentage of T and B lymphocytes positive for IGF-IR on IFN-A treated patients (P<0.001). Also an increase of IGF-IR mRNA expression could be detected in this group when compared with patients in hydroxyurea therapy (P<0.05). Our study suggest that IGF-IR is not directly implicated on CML installation and that the increased expression of IGF-IR on lymphoid cells of IFN-A treated patients could contribute to the immune recognition of malignant cell clone by enhancing immunocompetent cell proliferation and action.

Adolescent↗
PubMed2000

Identification of human chromosome 22 transcribed sequences with ORF expressed sequence tags.

Transcribed sequences in the human genome can be identified with confidence only by alignment with sequences derived from cDNAs synthesized from naturally occurring mRNAs. We constructed a set of 250,000 cDNAs that represent partial expressed gene sequences and that are biased toward the central coding regions of the resulting transcripts. They are termed ORF expressed sequence tags (ORESTES). The 250,000 ORESTES were assembled into 81,429 contigs. Of these, 1, 181 (1.45%) were found to match sequences in chromosome 22 with at least one ORESTES contig for 162 (65.6%) of the 247 known genes, for 67 (44.6%) of the 150 related genes, and for 45 of the 148 (30.4%) EST-predicted genes on this chromosome. Using a set of stringent criteria to validate our sequences, we identified a further 219 previously unannotated transcribed sequences on chromosome 22. Of these, 171 were in fact also defined by EST or full length cDNA sequences available in GenBank but not utilized in the initial annotation of the first human chromosome sequence. Thus despite representing less than 15% of all expressed human sequences in the public databases at the time of the present analysis, ORESTES sequences defined 48 transcribed sequences on chromosome 22 not defined by other sequences. All of the transcribed sequences defined by ORESTES coincided with DNA regions predicted as encoding exons by genscan. (http://genes.mit.edu/GENSCAN.html).

Chromosomes, Human, Pair 22↗
PubMed1999

Analysis of gonadotropin pulsatility in hirsute women with normal menstrual cycles and in women with polycystic ovary syndrome.

OBJECTIVE: To study the relation between plasma gonadotropin pulsatility, androgen levels, and estrogen levels in patients with polycystic ovary syndrome (PCOS), in hirsute women with normal menstrual cycles, and in healthy women. DESIGN: Prospective study. SETTING: University medical center-based cellular and molecular endocrinology laboratory. PATIENT(S): Eight healthy women (group 1), 9 hirsute women with normal menstrual cycles (group 2), and 19 women with PCOS (group 3). INTERVENTION(S): Plasma concentrations of LH and FSH were measured by RIA every 15 minutes for 12 hours. MAIN OUTCOME MEASURE(S): Rhythmic parameters of 12-hour LH and FSH secretion. RESULT(S): Rhythmic parameters of 12-hour LH secretion were significantly higher in patients with PCOS (group 3) than in controls (group 1) or in hirsute women with normal menstrual cycles (group 2). The frequency of LH pulses was statistically higher in patients with PCOS (group 3) than in controls (group 1). Statistically significant correlations were found when the frequency of LH pulses was plotted against basal LH concentrations and rhythmic parameters of 12-hour LH secretion. CONCLUSION(S): Luteinizing hormone pulse amplitude was higher in patients with PCOS than in hirsute women with normal menstrual cycles or in healthy women. The LH pulse frequency was increased only in patients with PCOS compared with healthy women and not in hirsute women with normal menstrual cycles.

Adolescent↗
PubMed1999

Evaluation of free insulin-like growth factor-I measurement on the diagnosis and follow-up treatment of growth hormone-deficient adult patients.

OBJECTIVE: Insulin-like growth factor (IGF-I) and IGF binding protein-3 (IGFBP-3) are GH-dependent and their concentrations have been used in the diagnosis of GH deficiency. Recently, the free fraction of IGF-I has received more attention. The aim of the study was to assess the role of free IGF-I in the diagnosis of GH deficiency in adults, and in follow-up during treatment with recombinant human GH (rhGH). DESIGN AND PATIENTS: We studied 24 adult patients with pituitary disease and GH deficiency and 25 matched controls. Nine patients were re-evaluated after 6 months of treatment with rhGH (0.25 U/kg/week). MEASUREMENTS: Serum levels of IGF-I, free IGF-I, IGFBP-3 and IGFBP-1 were measured by immunoradiometric assay. RESULTS: Serum free IGF-I levels were significantly lower in the GH deficient group than in the normal group (mean: 0.84 and 1.32 micrograms/l respectively, P = 0.0009). Furthermore, serum IGF-I levels were also lower (mean: 92.24 and 230.47 micrograms/l respectively, P < 0.0001). 63% of patients had serum IGF-I concentration below the normal range. For free IGF-I, 52% of the GH deficient patients showed levels below the lowest value obtained for the normal group. Seventy-five percent of the patients showed at least one of the two determinations below the normal range. The free-total IGF-I ratio was significantly higher (P = 0.025) in GH deficient group (range: 0.19-21.29, mean: 2.53) than in normal controls (range: 0.2-2.15, mean: 0.6). Regarding IGFBP-3 and IGFBP-1 no differences were observed between the two groups. During rhGH treatment the increase in serum total and free IGF-I and IGFBP-3 paralleled the beneficial effects on body composition. CONCLUSIONS: Free IGF-I may be another useful method for the diagnosis of GH deficiency, particularly if related to total IGF-I concentration.

Adult↗
PubMed1998

Effect of fat distribution on the pharmacokinetics of cortisol in obesity.

OBJECTIVE: Patients with predominantly upper body obesity are at greater risk for developing diabetes mellitus, hyperlipidemia, hypertension, and cardiovascular disease. Little is known about the mechanisms involved in the regulation of regional body distribution. It has been accepted that the accumulation of fat into adipose tissue depends on regional metabolic regulation of adipocytes and that glucocorticoids play a role in this mechanism. The aim of the present study is to investigate how the pharmacokinetics of cortisol correlate to intraabdominal and subcutaneous fat distribution in obese patients. METHODS: A group of 24 obese patients (13 males and 11 females) were submitted to a CT scan for intraabdominal and subcutaneous fat area evaluation. A 30-min cortisol infusion (0.25 mg/kg) was administered and plasma cortisol was measured over 6 hours. RESULTS: Patients with larger intraabdominal fat areas were found to have a higher cortisol clearance than those with lower intraabdominal fat areas. Cortisol clearance (both, absolute and body-weight corrected) showed a statistically significant correlation with intraabdominal fat area, either expressed by waist-hip ratio or obtained by computerized tomography. CONCLUSIONS: These findings indicate a more effective clearance capability for cortisol in patients with central obesity resulting in lowered cortisol plasma levels despite an increased cortisol secretion observed in this patient group.

Abdomen↗
PubMed1992

Short- and long-term gliclazide effects on pancreatic islet cell function and hepatic insulin extraction in non-insulin-dependent diabetes mellitus.

Nine non-obese males with non-insulin-dependent diabetes mellitus (NIDDM) were evaluated before and after 3 and 12 months (6 patients) treatment with the second generation hypoglycemic sulfonylurea: gliclazide. They underwent an oral glucose tolerance test, intravenous glucose and arginine tests measuring plasma insulin and C-peptide responses. Pre-hepatic insulin production and insulin delivery to peripheral tissues were calculated by deconvolution techniques and hepatic extraction of insulin estimated. An improvement was observed in the beta-cell function of the patients on gliclazide treatment: reduction of fasting plasma glucose associated with a progressive increase in C-peptide level but insulin levels decreased at 12 months, suggesting an increase in hepatic insulin extraction at this time. In the same way, while plasma glucose values after oral and i.v. glucose were greatly reduced at 3 and 12 months treatment, insulin did not change but C-peptide levels increased significantly at 12 month treatment. While the prehepatic insulin secretion rate increased progressively on gliclazide during all glucose challenges, the fractional hepatic insulin extraction fell after 3 and increased at 12 month treatment, with opposite changes in insulin delivered to peripheral tissues. Thus the insulinogenic effect of gliclazide could be masked during long-term administration by a concomitant effect of gliclazide which increases hepatic extraction of insulin. The maintenance of the responsiveness to the non-glucose secretagogue, arginine, as evaluated by the C-peptide levels, before and after correction of hyperglycemia, suggested improvement of beta-cell sensitivity to glucose after sulfonylurea treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Platelet-derived growth factor isoforms decrease insulin-like growth factor I gene expression in rat vascular smooth muscle cells and selectively stimulate the biosynthesis of insulin-like growth factor binding protein 4.

Platelet-derived growth factor (PDGF) is believed to be a critical mediator of vascular smooth muscle cell (SMC) proliferation. Because insulin-like growth factor (IGF) I (IGF-I) functions as a progression factor for the mitogenic effects of PDGF, we hypothesized that IGF-I gene expression and the production of IGF binding proteins (IGFBPs) by cultured rat aortic SMCs might be regulated by one or more of the three isoforms of PDGF: PDGF-AA, -BB, and -AB. IGF-I gene expression was highly dependent on cell density: IGF-I mRNA transcripts decreased markedly as a function of cell confluence. IGF-I mRNA content was inhibited to a similar degree by PDGF-AA, -BB, and -AB through a mechanism requiring protein synthesis. The inhibition was readily apparent at 4 hours, reaching approximately 25% of control levels after 24 hours. Radioimmunoassayable IGF-I was only barely detectable in SMC-conditioned serum-free medium and not significantly modulated by PDGF. Western ligand blot revealed that vascular SMCs release 30-kd and 24-kd IGFBP into serum-free conditioned medium. PDGF isoforms did not significantly alter release of the 30-kd IGFBP but evoked a fivefold to sixfold increase in the 24-kd IGFBP. The 24-kd IGFBP was found to comigrate with IGFBP-4, a recently identified binding protein that inhibits IGF action. The 30-kd protein was not merely a glycosylated form of IGFBP-4, because it was not sensitive to N-glycanase digestion. PDGF-AA, -BB, and -AB markedly induced expression of IGFBP-4 mRNA in a time- and concentration-dependent fashion. Vascular SMCs also express IGFBP-2 mRNA, but its abundance was not induced by PDGF. In conclusion, PDGF evokes a complex pattern of regulation of genes in the IGF/IGFBP system. By inhibiting IGF-I production and specifically inducing biosynthesis of the inhibitory binding protein IGFBP-4, PDGF may set in motion mechanisms to limit the final magnitude of the mitogenic response.

Animals↗
PubMed1992

Regulation of insulin-like growth factor-I and its receptor in rat aorta after balloon denudation. Evidence for local bioactivity.

Local production of growth factors may play a major role in vascular repair after injury. We examined the regulation of insulin-like growth factor-I (IGF-I) and its specific membrane receptor in balloon-denuded rat aorta. Aortic IGF-I mRNA and radioimmunoassayable IGF-I content increased severalfold after balloon denudation with a peak at 7 d after injury. This coincided with a reciprocal 25% decrease in IGF-I receptor mRNA content and a 40% decrease in total 125I-IGF-I binding. Scatchard analysis indicated a single class of binding sites, with a decrease in receptor number at 7 d compared to control and no change in affinity. By in situ hybridization the predominant site of IGF-I expression in the normal and the denuded vessel wall was the medial smooth muscle cell. After denudation there was a relative decrease in IGF-I receptor mRNA in the medial cells as compared to the neointima, suggesting that the site of IGF-I action was predominantly in the medial layer. These data suggest that local expression and action of IGF-I are significant in the promotion of smooth muscle cell proliferation after arterial injury.

Animals↗
PubMed1991

Abundant expression of parathyroid hormone-related protein in primary rat aortic smooth muscle cells accompanies serum-induced proliferation.

Parathyroid hormone-related protein (PTHrP), which is responsible for producing hypercalcemia in patients with humoral hypercalcemia of malignancy, has recently been identified in several normal tissues. Because PTHrP, like parathyroid hormone (PTH), is known to exhibit vasodilatory properties, we investigated the expression and regulation of PTHrP mRNA in cultured rat aortic smooth muscle cells (SMC). We report here that PTHrP mRNA is expressed in SMC and is markedly induced by serum in a time- and concentration-dependent fashion. Addition of 10% fetal calf serum to serum-deprived, confluent cells, resulted in a marked induction of PTHrP mRNA by 2 h with a peak at 4-6 h. PTHrP was detected in SMC by immunocytochemistry and radioimmunoassay of conditioned medium, and was shown to be up-regulated within 24 h after the addition of serum. The serum induction of PTHrP mRNA was blocked by actinomycin D and by cycloheximide indicating the need for protein synthesis to evoke the serum effect on PTHrP gene transcription. In addition, treatment with dexamethasone, which has been previously shown to reduce the constitutive expression of PTHrP in human cancer cells, also blunted the serum induction of PTHrP mRNA in SMC. Treatment of quiescent cells with the serum mitogens platelet-derived growth factor or insulin-like growth factor-I had no effect on PTHrP, whereas the vasoactive peptides endothelin, norepinephrine and thrombin stimulated PTHrP expression. Exogenous addition of recombinant PTHrP-(1-141) had no significant effect on SMC DNA synthesis as measured by [3H]thymidine incorporation. In summary, the abundance of PTHrP mRNA and the characteristics of its regulation in SMC suggest a major role for PTHrP as a local modulator in vascular smooth muscle.

Animals↗
PubMed1988

Criteria for the cure of acromegaly: comparison between basal growth hormone and somatomedin C plasma concentrations in active and non-active acromegalic patients.

Fasting plasma growth hormone (GH) and somatomedin C (SmC) levels were compared as criteria for the cure of acromegaly in 7 untreated and 16 treated acromegalic patients studied 1 to 16 yr after pituitary surgery and/or radiotherapy. The patients without active disease presented a significant correlation between GH and SmC. Only when basal GH was lower than 2.5 ng/ml were SmC values within the normal range. The subjects with active acromegaly (both treated and untreated) presenting GH higher than 5 ng/ml did not show any correlation between GH and SmC levels.

Acromegaly↗
PubMed1988

Somatomedin levels in the diagnosis and therapy of growth hormone deficiency.

Serum somatomedin-C (SM-C) and somatomedin (SM) concentrations were measured by, respectively, radioimmuno (SM-C RIA) and radioreceptor assays (SM RRA) in 3 groups of children with short stature. The patient population was different from previously reported series in that it was urban Brazilian, low income, and significantly older. Group A consisted of 6 male and 3 female children, aged 7.7-16.0 years, whose average peak plasma immunoreactive growth hormone (GH) was above 10 ng/ml. Group B contained 8 male and 5 female untreated GH-deficient patients, ranging in age from 9.5 to 21.0 years. In Group C there were 4 male and 1 female GH-deficient subjects treated with I.M. injections of GH (0.1 U/kg) from 1 month to 7 years. The mean +/- SE basal RIA SM-C (ng/ml) concentrations were significantly lower in groups B (34.2 +/- 8.8) and C (43.8 +/- 13.7) than A (214.3 +/- 42.7): A X B, P less than 0.001 and A X C, P less than 0.02. Likewise the mean +/- SE basal RRA SM (ng/ml) concentrations were significantly lower in groups B (78.9 +/- 17.6) and C (90.8 +/- 19.3) than group A (316.3 +/- 43.0): A X B, P less than 0.001 and A X C, P less than 0.002. A significant linear correlation was observed between RIA and RRA in group B (r = 0.84; P less than 0.001) and C (r = 0.96; P less than 0.01), but not for A (r = 0.61; P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗