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Biomedical subjects

G Palmieri

Publications and source records attributed to G Palmieri.

At least 55 records · Page 3Linked to original sources
PubMed2000

CD69-triggered ERK activation and functions are negatively regulated by CD94 / NKG2-A inhibitory receptor.

CD69 represents a functional triggering molecule on activated NK and T cells, capable of inducing cytotoxic activity and costimulating cytokine production. It belongs to the C-lectin type superfamily, and its gene maps in the NK gene complex, close to other genes coding for NK receptors. CD94 / NKG2-A complex is the inhibitory receptor for the non classical MHC class I molecule HLA-E on human NK cells. To investigate CD69-initiated signal transduction pathways, and to evaluate CD94 / NKG2-A interference on CD69 triggering ability, we have generated transfectants expressing both receptors in the RBL cell line. Here we report that CD69 engagement leads to the activation of extracellular signal-regulated kinase (ERK) enzymes belonging to the MAPK family, and that this event is required for CD69-mediated cell degranulation. Moreover, we show that the co-engagement of CD94 / NKG2-A inhibitory receptor effectively suppresses both CD69-triggered cell degranulation in RBL transfectants, through the inhibition of ERK activation, and CD69-induced cytotoxicity in human NK cells. Thus, here we provide new information on the molecular mechanisms initiated by CD69 activation receptor, and show that CD69-initiated signaling pathways and functional activity are negatively regulated by CD94 / NKG2-A inhibitory complex.

Animals↗
PubMed2000

Serum ECP and MPO are increased during exacerbations of chronic bronchitis with airway obstruction.

Many studies have demonstrated that, in asthma, serum levels of eosinophil cationic protein (ECP) are related to the activity and severity of the disease and can be used to evaluate the response to steroid treatment. During exacerbations of chronic bronchitis, airway inflammation shows some features of asthmatic inflammatory processes, with recruitment of eosinophils and recovery of significant amounts of ECP in bronchial lavage fluid (BAL). Involvement of neutrophils, with high levels of myeloperoxidase (MPO), is, on the contrary, typical of this latter disease, and not shared with asthma. In spite of the information collected with BAL and bronchial biopsy studies, few data still exist on serum levels of these proteins in chronic bronchitis. The objective of this study was to assess if serum levels of ECP and MPO are specifically increased in exacerbations of chronic bronchitis, as compared to other non-asthmatic acute respiratory disturbances. Serum ECP, MPO and immunoglobulin E (IgE) levels were measured in 17 non-atopic patients with exacerbation of chronic bronchitis with airway obstruction (COPD) and in 11 control subjects seeking emergency medical treatment for unrelated acute respiratory problems. Spirometry was performed in patients able to give the necessary collaboration. All the subjects of this study were recruited from the emergency department. Both ECP and MPO were significantly increased in serum from patients with exacerbated COPD (22.2 +/- 4.1 vs 9.5 +/- 1.4 mcg/L and 853 +/- 168 vs 375 +/- 41 mcg/L) and a strong correlation existed between these two variables (r = 0.782). A further control group was made of 11 patients with stable COPD. These subjects had levels of both ECP (13.1 +/- 2.7 mcg/L) and MPO (469 +/- 71) significantly lower than patients with exacerbated disease and higher than those without COPD. We conclude that serum ECP and MPO are increased during the exacerbations of COPD. These observations can give a basis for further studies aimed to evaluate the utility of these two proteins as markers of activity and severity of COPD.

Aged↗
PubMed2000

Sensitivity and specificity of epiluminescence microscopy: evaluation on a sample of 2731 excised cutaneous pigmented lesions. The Melanoma Cooperative Study.

To evaluate the role of epiluminescence microscopy (ELM) in the differential diagnosis of cutaneous pigmented lesions, and to improve the early diagnosis of cutaneous malignant melanoma (CMM), 15,719 pigmented lesions from 8782 consecutive patients were evaluated using ELM with a hand-held video microscope imaging system (MS 500B Micro-Scopeman, Moritex). Comparison between risk levels as inferred from ELM screening and histology was performed on 2731 surgically excised lesions. ELM sensitivity, specificity, positive and negative predictive values, as well as agreement with histological results for the different subgroups of lesions, were determined. Overall agreement was 87.3% (ranging from 85.1% to 92.2% for melanocytic and non-melanocytic lesions, respectively); sensitivity and specificity were high (values ranging from 87.3% to 96.3% among different subsets of ELM-analysed lesions) and statistically significant (P < 0.0001). ELM screening identified 165 new cases of CMM with a high proportion of lesions (115; 70%) in an early phase of tumour growth (Breslow thickness </= 1.5 mm). Thus, ELM is helpful to the clinician in deciding which pigmented lesions need surgical excision, as well as in diagnosing early CMM lesions.

Adolescent↗
PubMed2000

Identification of a founder BRCA2 mutation in Sardinia.

Sardinian population can be instrumental in defining the molecular basis of cancer, using the identity-by-descent method. We selected seven Sardinian breast cancer families originating from the northern-central part of the island with multiple affected members in different generations. We genotyped 106 members of the seven families and 20 control nuclear families with markers flanking BRCA2 locus at 13q12-q13. The detection of a common haplotype shared by four out of seven families (60%) suggests the presence of a founder BRCA2 mutation. Direct sequencing of BRCA2 coding exons of patients carrying the shared haplotype, allowed the identification of a 'frame-shift' mutation at codon 2867 (8765delAG), causing a premature termination-codon. This mutation was found in breast cancer patients as well as one prostate and one bladder cancer patient with shared haplotype. We then investigated the frequency of 8765delAG in the Sardinian breast cancer population by analysing 270 paraffin-embedded normal tissue samples from breast cancer patients. Five patients (1.7%) were found to be positive for the 8765delAG mutation. Discovery of a founder mutation in Sardinia through the identity-by-descent method demonstrates that this approach can be applied successfully to find mutations either for breast cancer or for other types of tumours.

BRCA2 Protein↗
PubMed2000

Definition of the role of chromosome 9p21 in sporadic melanoma through genetic analysis of primary tumours and their metastases. The Melanoma Cooperative Group.

Malignant melanoma (MM) is thought to arise by sequential accumulation of genetic alterations in normal melanocytes. Previous cytogenetic and molecular studies indicated the 9p21 as the chromosomal region involved in MM pathogenesis. In addition to the CDKN genes (p16/CDKN2A, p15/CDKN2B and p19(ARF), frequently inactivated in familial MM), widely reported data suggested the presence within this region of other melanoma susceptibility gene(s). To clearly assess the role of the 9p21 region in sporadic melanoma, we evaluated the presence of microsatellite instability (MSI) and loss of heterozygosity (LOH) in primary tumours as well as in synchronous or asynchronous metastases obtained from the same MM patients, using 9 polymorphic markers from a 17-cM region at 9p21. LOH and MSI were found in 27 (41%) and 11 (17%), respectively, out of 66 primary tumours analysed. In corresponding 58 metastases, MSI was found at higher rate (22; 38%), whereas a quite identical pattern of allelic deletions with 27 (47%) LOH+ cases were observed. Although the CDKN locus was mostly affected by LOH, an additional region of common allelic deletion corresponding to marker D9S171 was also identified. No significant statistical correlation between any 9p21 genetic alteration (LOH, MSI or both) and clinicopathological parameters was observed.

Adolescent↗
PubMed2000

Copper induction of laccase isoenzymes in the ligninolytic fungus Pleurotus ostreatus.

Pleurotus ostreatus is a white rot basidiomycete that produces several extracellular laccase isoenzymes, including phenol oxidase A1b (POXA1b), POXA2, and POXC. POXC was the most abundant isoenzyme produced under all of the growth conditions examined in this study. Copper was the most efficient inducer of laccase activity among the putative inducers tested. The amounts of all of the previously described laccase isoenzymes increased substantially in copper-supplemented cultures. Under these conditions expression of POX isoenzymes was regulated at the level of gene transcription. It is worth noting that poxa1b mRNA was the most abundant induced transcript at all of the growth times analyzed, and the amount of this mRNA increased until day 7. The discrepancy between the poxa1b transcript and protein amounts can be explained by the presence of a high level of the protein in P. ostreatus cellular extract, which indicated that the POXA1b isoenzyme could be inefficiently secreted and/or that its physiological activity could occur inside the cell or on the cell wall. Moreover, the POXA1b isoenzyme behaved uniquely, as its activity was maximal on the second day of growth and then decreased. An analysis performed with protease inhibitors revealed that the loss of extracellular POXA1b activity could have been due to the presence of specific proteases secreted into the copper-containing culture medium that affected the extracellular POXA1b isoenzyme.

Copper↗
PubMed2000

CEOP-B/VIMB vs. promace-CytaBOM in the treatment of intermediate or high grade non-Hodgkin's lymphoma: A randomised multicenter study of Southern Italy Cooperative Group.

From January 1992 to December 1995, 129 patients with previously untreated non-Hodgkin's lymphoma were randomised in a phase III multicenter trial to receive CEOP-B/VIMB or ProMACE-CytaBOM. Eligibility criteria included intermediate or high grade lymphoma (follicular large cell, diffuse small cleaved-cell, diffuse mixed, diffuse large-cell and immunoblastic) with an Ann Arbor stage II bulky, III or IV. All patients entered into the study were considered evaluable according to intent to treat analysis. At a median follow-up of 60 months there were no significant differences between the treatment response rates [82% (60%CR) for CEOP-B/VIMB vs. 81% (69% CR) for ProMACE-CytaBOM]. Conversely, with regard to disease-free survival, a significant difference was observed between the two treatment arms (42% for CEOP-B/VIMB vs. 24% for ProMACE-CytaBOM at 5 years; p=0.046). However, this difference did not translate in a significant difference in overall survival (45% vs. 39% at 5 years). Moreover, when response rates and outcome were analysed for different prognostic subgroups according to International Prognostic Index, no significant differences were observed between the treatment groups. It is important to note that neither regimen was able to improve outcome of poor risk patients who fared badly with both treatments (median survival 9 and 8 months respectively). Toxicity was also similar in both treatments with grade 3-4 leukopenia observed in 39% and 47% of cases and grade 3-4 thrombocytopenia in 24% and 27% of cases respectively. In conclusion, in this study CEOP-B/VIMB was not superior to ProMACE-CytaBOM in aggressive lymphomas and the alternating strategy failed to improve outcome of poor risk patients in which newer more aggressive treatments are needed.

Adolescent↗
PubMed2000

Evaluation of polyamide synthetic hair. A long-term clinical study.

BACKGROUND: Different methods of hair restoration surgery exist: expanders, rotation flaps, autotransplantation and artificial hair implant. METHODS: The authors reviewed 196 patients who underwent hair implantation 2 years before with a highly biocompatible polyamide fiber. Indications, contraindications and complications of the procedure are outlined. RESULTS: Clinical subjective and photographic objective judgement, evaluation of Hamilton scale grading and covered area rate show very satisfactory improvements. Relevant adverse events were limited to 1.02%. CONCLUSIONS: A careful medical follow-up with regular scalp check-up minimizes complications to a very acceptable rate and overall results are definitely satisfying.

Adult↗
PubMed1999

Protein and gene structure of a blue laccase from Pleurotus ostreatus1.

A new laccase isoenzyme (POXA1b, where POX is phenol oxidase), produced by Pleurotus ostreatus in cultures supplemented with copper sulphate, has been purified and fully characterized. The main characteristics of this protein (molecular mass in native and denaturing conditions, pI and catalytic properties) are almost identical to the previously studied laccase POXA1w. However, POXA1b contains four copper atoms per molecule instead of one copper, two zinc and one iron atom per molecule of POXA1w. Furthermore, POXA1b shows an unusually high stability at alkaline pH. The gene and cDNA coding for POXA1b have been cloned and sequenced. The gene coding sequence contains 1599 bp, interrupted by 15 introns. Comparison of the structure of the poxa1b gene with the two previously studied P. ostreatus laccase genes (pox1 and poxc) suggests that these genes belong to two different subfamilies. The amino acid sequence of POXA1b deduced from the cDNA sequence has been almost completely verified by means of matrix-assisted laser desorption ionization MS. It has been demonstrated that three out of six putative glycosylation sites are post-translationally modified and the structure of the bound glycosidic moieties has been determined, whereas two other putative glycosylation sites are unmodified.

Amino Acid Sequence↗
PubMed1999

CD94/NKG2-A inhibitory complex blocks CD16-triggered Syk and extracellular regulated kinase activation, leading to cytotoxic function of human NK cells.

The CD94/NKG2-A complex is the inhibitory receptor for the nonclassical MHC class I molecule HLA-E on human NK cells. Here we studied the molecular mechanisms underlying the inhibitory activity of CD94/NKG2-A on NK cell functions by analyzing its interference on CD16-initiated signaling pathways involved in the control of cytolytic activity. Both tyrosine phosphorylation and activation of Syk kinase together with tyrosine phosphorylation of CD16 receptor zeta subunit are markedly inhibited by the coengagement of CD94/NKG2-A complex. As a downstream consequence, CD94/NKG2-A cross-linking impairs the CD16-induced activation of extracellular regulated kinases (ERKs), a pathway involved in NK cytotoxic function. The block of ERK activation is exerted at an early, PTK-dependent stage in the events leading to p21ras activation, as the CD16-induced tyrosine phosphorylation of Shc adaptor protein and the formation of Shc/Grb-2 complex are abrogated by CD94/NKG2-A simultaneous engagement. Our observations indicate that CD94/NKG2-A inhibits the CD16-triggered activation of two signaling pathways involved in the cytotoxic activity of NK cells. They thus provide molecular evidence to explain the inhibitory function of CD94/NKG2-A receptor on NK effector functions.

Animals↗
PubMed1999

A pilot study on the safety and effectiveness of immunosuppression without prednisone after liver transplantation.

BACKGROUND: Corticosteroids are commonly used in the immunosuppression therapy after liver transplantation, yet are associated with considerable side effects. Retrospective studies have shown that corticosteroids can be safely withdrawn from months to years after transplant. We prospectively investigated the effects of early immunosuppression without the use of corticosteroids on graft outcome and transplant complications. METHODS: Forty-five patients undergoing liver transplantation were randomized to receive immunosuppression composed of cyclosporine microemulsion and azathioprine with (n=22) or without prednisone (n=23), in conventional doses. In those patients who received prednisone, this was withdrawn within 3 months after transplant. The median follow-up of survivors was 14 months (range: 6-24). The study end points were to determine graft survival and function, infectious complications, including hepatitis C virus (HCV)-RNA levels in HCV-infected recipients, acute rejection, kidney function, and metabolic complications. RESULTS: Eleven deaths occurred, 6 of which were in the prednisone group. Two-year survival did not differ between patients treated with or without prednisone (70.2% vs. 78.3%, P=0.83), nor did the causes of death. No differences were observed with regard to graft function, renal function, and infectious complications. In the subset of patients who received transplants for HCV-related cirrhosis, the dynamics of virus replication HCV-RNA was faster among those treated with prednisone. The incidence and severity of acute rejection was similar in the two groups. More than 80% of acute rejections in both groups were classified as mild or moderate and underwent spontaneous resolution. Only two patients in each group had severe acute rejection requiring additional treatment with high-dose steroids. Patients receiving prednisone tended to have greater biochemical signs of cholestasis, higher serum cholesterol and glucose levels, and more frequent insulin requirement than those treated without corticosteroids. CONCLUSIONS: Liver transplantation can be performed safely without using corticosteroids in the early postoperative course, and there is no need for routine aggressive steroid treatment of established acute rejections.

Adult↗
PubMed1999

Association of polo-like kinase with alpha-, beta- and gamma-tubulins in a stable complex.

The polo-like kinase (Plk) family has been shown to have an important role in the regulation of the cell-division cycle, especially in organization of the spindle structure, in species from fungi to humans. Recent reports have demonstrated that in mammalian cells Plk is associated with components of the anaphase-promoting complex and a peptidyl-prolyl isomerase, Pin1. To characterize a putative Plk-containing complex, we fractionated mitotic cell lysates on a gel-filtration column. The Plk complex was eluted from the column at molecular sizes ranging from 669 to 2500 kDa in the presence of detergent and high concentrations of salt. Specific associations of Plk with alpha-, beta- and gamma-tubulins in both interphase and mitotic cells were shown by reciprocal immunoprecipitations and immunoblottings and were independent of the microtubule polymerization state, whereas binding assays in vitro indicated that Plk interacts with alpha- and beta-tubulins directly. In addition, mitotic Plk was able to phosphorylate associated tubulins in vitro. Finally, we show that the kinase domain of the Plk molecule is both required and sufficient for its binding to tubulins in vivo. The specific interaction between Plk and tubulins might provide a molecular basis for the physiological functions of Plk in regulating the cell cycle, particularly in establishing the normal bipolar spindle.

Amino Acid Sequence↗
PubMed1999

Role for the Rac1 exchange factor Vav in the signaling pathways leading to NK cell cytotoxicity.

Here we investigate the activation of and a possible role for the hematopoietic Rac1 exchange factor, Vav, in the signaling mechanisms leading to NK cell-mediated cytotoxicity. Our data show that direct contact of NK cells with a panel of sensitive tumor targets leads to a rapid and transient tyrosine phosphorylation of Vav and to its association with tyrosine-phosphorylated Syk. Vav tyrosine phosphorylation is also observed following the activation of NK cells through the low-affinity Fc receptor for IgG (Fc gamma RIII). In addition, we demonstrate that both direct and Ab-mediated NK cell binding to target cells result in the activation of nucleotide exchange on endogenous Rac1. Furthermore, Vav antisense oligodeoxynucleotide treatment leads to an impairment of NK cytotoxicity, with Fc gamma RIII-mediated killing being more sensitive to the abrogation of Vav expression. These results provide new insight into the signaling pathways leading to cytotoxic effector function and define a role for Vav in the activation of NK cell-mediated killing.

Animals↗
PubMed1999

Beta 1 integrin cross-linking inhibits CD16-induced phospholipase D and secretory phospholipase A2 activity and granule exocytosis in human NK cells: role of phospholipase D in CD16-triggered degranulation.

Recent data indicate that integrin-generated signals can modulate different receptor-stimulated cell functions in both a positive (costimulation) and a negative (inhibition) fashion. Here we investigated the ability of beta 1 integrins, namely alpha 4 beta 1 and alpha 5 beta 1 fibronectin receptors, to modulate CD16-triggered phospholipase activation in human NK cells. beta 1 integrin simultaneous cross-linking selectively inhibited CD16-induced phospholipase D (PLD) activation, without affecting either phosphatidylinositol-phospholipase C or cytosolic phospholipase A2 (PLA2) enzymatic activity. CD16-induced secretory PLA2 (sPLA2) protein release as well as its enzymatic activity in both cell-associated and soluble forms were also found to be inhibited upon beta 1 integrin coengagement. The similar effects exerted by specific PLD pharmacological inhibitors (2,3-diphosphoglycerate, ethanol) suggest that in our experimental system, sPLA2 secretion and activation are under the control of a PLD-dependent pathway. By using pharmacological inhibitors (2,3-diphosphoglycerate, wortmannin, ethanol) we also demonstrated that PLD activation is an important step in the CD16-triggered signaling cascade that leads to NK cytotoxic granule exocytosis. Consistent with these findings, fibronectin receptor engagement, by either mAbs or natural ligands, resulted in a selective inhibition of CD16-triggered, but not of PMA/ionomycin-induced, degranulation that was reversed by the exogenous addition of purified PLD from Streptomyces chromofuscus.

Cell Degranulation↗