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Biomedical subjects

Salvatore Benvenga

Publications and source records attributed to Salvatore Benvenga.

At least 19 recordsLinked to original sources
PubMed2006

Acromegaly and coronary disease: an integrated evaluation of conventional coronary risk factors and coronary calcifications detected by computed tomography.

CONTEXT: Coronary atherosclerosis in acromegaly was not extensively investigated in the literature until now. At autopsy, it was demonstrated in about 20% of patients with long-lasting disease, and myocardial infarction was reported as cause of death in a quarter of acromegalics. OBJECTIVE: The objective of the study was to evaluate coronary atherosclerosis in a cohort of acromegalics with controlled or uncontrolled disease. DESIGN: Coronary risk was evaluated by the Framingham algorithm, according to the Framingham score (FS). Patients were stratified into low (<6%), intermediate (6-20%), and high (>20%) midterm risk. Coronary calcium deposits were detected by multidetector computed tomography and measured by the Agatston algorithm. Coronary artery calcium [Agatston score (AS)] was quantified at the level of left main artery, left anterior descendent artery, left circumflex artery, right coronary artery, and posterior descendent artery. Total AS values in healthy persons are less than 50 (aged < 60 yr) and less than 300 (age > or = 60 yr). PATIENTS: Thirty-nine patients (12 males and 27 females, aged 53.0 +/- 2.1 yr) were evaluated. In each patient, the mean of at least four determinations of serum IGF-I, assayed during the last 2 yr before study, was normalized for the age-matched normal range, and the result was presented as sd value (IGF-I sd). On the basis of serum IGF-I sd, acromegaly was considered controlled (< or =1.9 sd; n = 24) or uncontrolled (> or = 2.0 sd; n = 15). RESULTS: The FS was intermediate in 12 and high in two acromegalics. Overall, the FS was not correlated with serum GH values and IGF-I sd. Mean FS was not significantly different between patients with controlled and uncontrolled acromegaly. Total AS was increased in nine patients, most frequently in left anterior descendent, left circumflex, and left main arteries. In these nine patients, mean AS was similar in individuals with controlled and those with uncontrolled acromegaly, and the rate of 17% patients with controlled disease having increased AS was not statistically different from the rate of 33% uncontrolled acromegalics. Total AS was increased in six of 12 males and in three of 27 females (chi(2) 7.1, P < 0.01). Overall, total AS correlated with FS (r(2) = 0.4, P < 0.0002) but not age, body mass index, disease duration, indexed left ventricular mass, serum cholesterol, triglycerides, GH, or IGF-I levels. Increased AS was more frequently observed in acromegalics with diabetes mellitus (chi(2) = 5.2, P < 0.05) or hypertension (chi(2) = 9.8, P < 0.002) but not in smokers (chi(2) = 1.34, P = NS). Seven of nine patients with coronary calcium deposits had a FS greater than 6%. In six of 13 patients with FS greater than 6%, multidetector computed tomography did not demonstrate coronary calcifications. CONCLUSIONS: In our study, the integrated evaluation of FS and AS showed that 41% of acromegalics are at risk for coronary atherosclerosis and that coronary calcifications were evident in about half of them despite the fact that myocardial infarction was not more frequent in acromegalic patients than the general population. Moreover, the control of acromegaly did not influence significantly the extent of coronary atherosclerosis.

Acromegaly↗
PubMed2006

Human thyroid autoantigens and proteins of Yersinia and Borrelia share amino acid sequence homology that includes binding motifs to HLA-DR molecules and T-cell receptor.

We previously reported that the spirochete Borrelia burgdorferi could trigger autoimmune thyroid diseases (AITD). Subsequently, we showed local amino acid sequence homology between all human thyroid autoantigens (human thyrotropin receptor [hTSH-R], human thyroglobulin [hTg], human thyroperoxidase [hTPO], human sodium iodide symporter [hNIS]) and Borrelia proteins (n = 6,606), and between hTSH-R and Yersinia enterocolitica (n = 1,153). We have now updated our search of homology with Borrelia (n = 11,198 proteins) and extended our search on Yersinia to the entire species (n = 40,964 proteins). We also searched the homologous human and microbial sequences for peptide-binding motifs of HLA-DR molecules, because a number of these class II major histocompatibility complex (MHC) molecules (DR3, DR4, DR5, DR8, and DR9) are associated with AITD. Significant homologies were found for only 16 Borrelia proteins (5 with hTSH-R, 2 with hTg, 3 with hTPO, and 6 with hNIS) and only 19 Yersinia proteins (4 with hTSH-R, 2 with hTg, 2 with hTPO, and 11 with hNIS). Noteworthy, segments of thyroid autoantigens homologous to these microbial proteins are known to be autoantigenic. Also, the hTSH-R homologous region of one Borrelia protein (OspA) contains an immunodominant epitope that others have found to be homologous to hLFA-1. This is of interest, as the hLFA-1/ICAM-1 ligand/receptor pair is aberrantly expressed in the follicular cells of thyroids affected by Hashimoto's thyroiditis. A computer-assisted search detected antigenic peptide binding motifs to the DR molecules implicated in AITD. In conclusion, our in silico data do not directly demonstrate that Borrelia and Yersinia proteins trigger AITD but suggest that a restricted number of them might have the potential to, at least in persons with certain HLA-DR alleles.

Amino Acid Motifs↗
PubMed2006

Germline mutation of von Hippel-Lindau (VHL) gene 695 G>A (R161Q) in a patient with a peculiar phenotype with type 2C VHL syndrome.

Von Hippel-Lindau (VHL) disease is an autosomal dominant familial neoplastic disorder with an estimated birth incidence of approximately 1:36000 live. VHL has intrafamilial variability expression and it is characterized by the predisposition to develop hemangioblastomas of the central nervous system and retina, pheochromocytomas, clear-cell renal carcinoma, adenomas, and carcinomas of the pancreas, paragangliomas, renal and pancreatic cysts, papillary cystadenomas of the epididymis and, rarely, cystadenomas of the endolymphatic sac tumor and broad ligament. We describe a Sicilian girl with type 2C VHL who showed the apparently de novo mutation R161Q in association with an extra-axial supratentorial frontal meningioma, which can be included as a characteristic sign in VHL.

Adult↗
PubMed2005

Identification of potentially cross-reactive peanut-lupine proteins by computer-assisted search for amino acid sequence homology.

BACKGROUND: Allergic cross-reactions are an issue of major concern because of implications for public health. The molecular basis of cross-allergy is the similarity of epitopes belonging to proteins of different organisms. Lupine is an emerging cause of food allergy, which has become a 'hot topic' because of recent large-scale introduction into processed foods and frequent cross-reactions with other members of the legume family. However, no lupine allergen has been characterized thus far. Prompted by a recently reported case of peanut-lupine cross-allergy, we wished to identify the possible cross-reactive allergen(s) between the two vegetal species. METHODS: We used computer-aided amino acid sequence comparison, a well-established technique for the study of protein homology, and followed the FAO/WHO guidelines for the identification of potential allergens. We also performed a three-dimensional modeling of the suspected cross-reactive proteins to compare their molecular surfaces. RESULTS: We found a highly significant sequence homology and molecular similarity between allergen Ara h 8 of peanut and pathogenesis-related protein PR-10 of white lupine. Another protein of lupine, the beta-conglutin precursor, was found to be significantly homologous to the Ara h 1 allergen of peanut. The molecular surfaces of Ara h 8 and PR-10 were remarkably similar. CONCLUSIONS: Our in silico data allow to predict the allergenicity of PR-10 and beta-conglutin precursor of white lupine according to FAO/WHO guidelines. Amino acid sequence homology also suggests that these proteins could be responsible, at least in part, for some of the allergic cross-reactions between peanut and lupine reported in the literature.

Allergens↗
PubMed2005

Residual pituitary function after brain injury-induced hypopituitarism: a prospective 12-month study.

CONTEXT: Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are conditions at high risk for the development of hypopituitarism. OBJECTIVE: The objective of the study was to clarify whether pituitary deficiencies and normal pituitary function recorded at 3 months would improve or worsen at 12 months after the brain injury. DESIGN AND PATIENTS: Pituitary function was tested at 3 and 12 months in patients who had TBI (n = 70) or SAH (n = 32). RESULTS: In TBI, the 3-month evaluation had shown hypopituitarism (H) in 32.8%. Panhypopituitarism (PH), multiple (MH), and isolated (IH) hypopituitarism had been demonstrated in 5.7, 5.7, and 21.4%, respectively. The retesting demonstrated some degree of H in 22.7%. PH, MH, and IH were present in 5.7, 4.2, and 12.8%, respectively. PH was always confirmed at 12 months, whereas MH and IH were confirmed in 25% only. In 5.5% of TBI with no deficit at 3 months, IH was recorded at retesting. In 13.3% of TBI with IH at 3 months, MH was demonstrated at 12-month retesting. In SAH, the 3-month evaluation had shown H in 46.8%. MH and IH had been demonstrated in 6.2 and 40.6%, respectively. The retesting demonstrated H in 37.5%. MH and IH were present in 6.2 and 31.3%, respectively. Although no MH was confirmed at 12 months, two patients with IH at 3 months showed MH at retesting; 30.7% of SAH with IH at 3 months displayed normal pituitary function at retesting. In SAH, normal pituitary function was always confirmed. In TBI and SAH, the most common deficit was always severe GH deficiency. CONCLUSION: There is high risk for H in TBI and SAH patients. Early diagnosis of PH is always confirmed in the long term. Pituitary function in brain-injured patients may improve over time but, although rarely, may also worsen. Thus, brain-injured patients must undergo neuroendocrine follow-up over time.

Adult↗
PubMed2005

Brain injury and hypopituitarism: the historical background.

In the year 2000, the latest review on post-head trauma hypopituitarism (PHTH) collected 367 cases of isolated or multiple deficiency of anterior pituitary hormones subsequent to traumatic brain injury. The first patient had been published in 1918 and the latest 15 were my personal observations reported in the said review. In the previous review on PHTH, which was published in 1986, a total of only 53 cases had been collected. The interest triggered by the latest review, which concluded that PHTH was indeed less rare than commonly believed, was such that a total of 192 cases have been reported from year 2000 through April, 2005.

Brain Injuries↗
PubMed2004

Homologies between proteins of Borrelia burgdorferi and thyroid autoantigens.

Subclinical exposure to microbic antigens that share amino acid sequence homology with self antigens might trigger autoimmune diseases in genetically predisposed individuals via molecular mimicry. Genetic predisposition to Graves' disease (GD) or Hashimoto's thyroiditis (HT) is conferred by HLA loci DR3 or DR5, respectively. Yersinia enterocolitica (YE) outer proteins (YOPs) are candidate triggers based on the high prevalence of serum antibodies (Ab) against YOPs in autoimmune thyroid diseases (AITD) and reactivity of these Ab with hTSH-R, suggesting homology between YOPs and hTSH-R. We have reported previously that the spirochete Borrelia burgdorferi (Bb) could be another trigger. We have explored further the homology of hTSH-R with YE and Bb. Using the Basic Local Alignment Search Tool (BLAST), we found four matches with YE and five matches with Bb . Residues 22-272, 186-330, 319-363 and 684-749 of hTSH-R matched YopM, Ysp, exopolygalacturonase and SpyA of YE (identity 23-31%, similarity 40-48%). Residues 112-205, 127-150, 141-260, 299-383 and 620-697 of hTSH-R matched outer surface protein A, flagellar motor rotation protein A, two hypothetical proteins (BBG02 and BBJ08) and DNA recombinase/ATP dependent helicase of Borrelia (identity 27-50%, similarity 40-75%). Interestingly, the above hTSH-R regions coincide with (or include) known human T-cell epitopes: aa 52-71, 140-176, 240-270, 340-380 and 441-661. Our data strengthen the hypothesis of Bb and YE as environmental triggers of AITD in genetically predisposed persons through molecular mimicry mechanisms.

Autoantigens↗
PubMed2004

Traumatic brain injury and subarachnoid haemorrhage are conditions at high risk for hypopituitarism: screening study at 3 months after the brain injury.

OBJECTIVE: Acquired hypopituitarism in adults is obviously suspected in patients with primary hypothalamic-pituitary diseases, particularly after neurosurgery and/or radiotherapy. That brain injuries (BI) can cause hypopituitarism is commonly stated and has been recently emphasized but the management of BI patients does not routinely include neuroendocrine evaluations. AIM: To clarify the occurrence of hypopituitarism in patients after traumatic brain injury (TBI) or subarachnoid haemorrhage (SAH) 3 months after the BI. SUBJECTS AND METHODS: The occurrence of hypopituitarism in conscious patients after traumatic brain injury [TBI, n = 100, 31 women, 69 men; age 37.1 +/- 1.8 years; body mass index (BMI) 23.7 +/- 0.4 kg/m(2); Glasgow Coma Scale (GCS) 3-15] or subarachnoid haemorrhage [SAH, n = 40, 14 men, 26 wpmen, 51.0 +/- 2.0 years; 25.0 +/- 0.6 kg/m(2); Fisher's scale 1-4] was studied in a multicentre study 3 months after the BI. All patients underwent wide basal hormonal evaluation; the GH/IGF-I axis was evaluated by GHRH + arginine test and IGF-I measurement. RESULTS: In TBI patients, some degree of hypopituitarism was shown in 35%. Total, multiple and isolated deficits were present in 4, 6 and 25%, respectively. Diabetes insipidus was present in 4%. Secondary adrenal, thyroid and gonadal deficit was present in 8, 5 and 17%, respectively. Severe GH deficiency (GHD) was the most frequent pituitary defect (25%). In SAH patients, some degree of hypopituitarism was shown in 37.5%. Despite no total hypopituitarism, multiple and isolated deficits were present in 10 and 27.5%, respectively. Diabetes insipidus was present in 7.5%. Secondary adrenal, thyroid and gonadal deficit was present in 2.5, 7.5 and 12.5%, respectively. Severe GHD was the most frequent defect (25%). CONCLUSIONS: TBI and SAH are conditions associated with high risk of acquired hypopituitarism. The pituitary defect is often multiple and severe GHD is the most frequent defect. Thus neuroendocrine evaluations are always mandatory in patients after brain injuries.

Adult↗
PubMed2004

Effects of carnitine on thyroid hormone action.

By experiments on cells (neurons, hepatocytes, and fibroblasts) that are targets for thyroid hormones and a randomized clinical trial on iatrogenic hyperthyroidism, we validated the concept that L-carnitine is a peripheral antagonist of thyroid hormone action. In particular, L-carnitine inhibits both triiodothyronine (T3) and thyroxine (T4) entry into the cell nuclei. This is relevant because thyroid hormone action is mainly mediated by specific nuclear receptors. In the randomized trial, we showed that 2 and 4 grams per day of oral L-carnitine are capable of reversing hyperthyroid symptoms (and biochemical changes in the hyperthyroid direction) as well as preventing (or minimizing) the appearance of hyperthyroid symptoms (or biochemical changes in the hyperthyroid direction). It is noteworthy that some biochemical parameters (thyrotropin and urine hydroxyproline) were refractory to the L-carnitine inhibition of thyroid hormone action, while osteocalcin changed in the hyperthyroid direction, but with a beneficial end result on bone. A very recent clinical observation proved the usefulness of L-carnitine in the most serious form of hyperthyroidism: thyroid storm. Since hyperthyroidism impoverishes the tissue deposits of carnitine, there is a rationale for using L-carnitine at least in certain clinical settings.

Bone Density↗
PubMed2004

Clinico-pathological significance of cell-type-specific loss of heterozygosity on chromosome 7q21: analysis of 318 microdissected thyroid lesions.

A careful pathological examination often reveals the presence of different lesions at various stages of tumor progression and invasion, even in those thyroid glands presenting with solitary nodules. Each thyroid lesion is composed of many different cell types, reflecting the marked heterogeneity of normal thyroid tissue. Among the different chromosome regions altered in thyroid tumors, 7q21 appears to be specifically involved in malignant tumors, especially of the follicular type. This study was conducted to analyze the loss of heterozygosity (LOH) pattern at 7q21 in pure populations of cells from each single lesion harbored in surgically removed thyroid glands, and to evaluate its clinical significance. One hundred and forty-two thyroid glands were examined, all showing, as a common trait, a goitrous appearance associated with one single lesion in 114 cases and with more than one in the remaining 28 cases. A total number of 318 lesions was analyzed, consisting of 142 goiters (TG), 48 hyperplasias (TH), 80 adenomas (TA) and 48 carcinomas (TC). Five different types of cells were isolated by laser capture microdissection from each lesion. DNA was analyzed by PCR and polyacrylamide gel electrophoresis in search of LOH affecting five microsatellite markers, D7S660, D7S630, D7S492, D7S657, and D7S689. We detected LOH at 7q21 not only in thyroid malignant tumors but also in benign lesions. Allelic loss occurred exclusively in dark nucleus and eosinophilic cytoplasm cells, commonly observed in the follicular type of lesions. In these types of lesions allelic loss frequency increases along with neoplastic transformation (9% in TG, 41% in TH, 68% in TA and 100% in TC), and is directly correlated with thyroid gland volume as well as with the presence of multiple lesions. The highest LOH rate was observed for D7S492, indicating that the recurrent region of deletion was localized at the corresponding genetic locus at 7q21.2, in the same position where the common fragile site FRA7E was previously mapped. LOH at this locus represents an early event in the development of follicular TC and is associated with intense growth of thyroid glands.

Adenocarcinoma, Follicular↗
PubMed2003

L-carnitine: A nutritional modulator of glucocorticoid receptor functions.

L-carnitine is an essential nutrient with a major role in cellular energy production. There is evidence that, at high doses, L-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. To explore the molecular basis of this effect, we tested the influence of L-carnitine on glucocorticoid receptor-alpha (GRalpha) functions. Millimolar concentrations of L-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [3H]dexamethasone to GRalpha by decreasing the affinity of this receptor for its steroid ligand. At the same concentrations, L-carnitine was able to trigger nuclear translocation of green fluorescent protein (GFP)-fused human GRalpha and transactivate the glucocorticoid-responsive mouse mammary tumor virus (MMTV) and TAT3 promoters in a dose-dependent fashion. This effect was solely dependent on the presence of glucocorticoid-responsive elements on the promoter and on the expression of functional GRalpha by the cell. Finally, similarly to glucocorticoids, L-carnitine suppressed tumor necrosis factor-alpha (TNFalpha) and interleukin-12 release by human primary monocytes stimulated with lipopolysaccharide ex vivo. Both GRalpha transactivation and cytokine suppression by L-carnitine were abrogated by the GRalpha-antagonist RU 486. Taken together, our results suggest that pharmacological doses of L-carnitine can activate GRalpha and, through this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids.

Active Transport, Cell Nucleus↗