PubMed Health⌕ Search

Biomedical subjects

G Salvatore

Publications and source records attributed to G Salvatore.

At least 19 recordsLinked to original sources
PubMed2006

Microcystin diversity in a Planktothrix rubescens population from Lake Albano (Central Italy).

The cyanobacterium Planktothrix rubescens Anagnostidis & Komarek (previously Oscillatoria rubescens DC ex Gomont) is present in several Italian lakes and it is known to produce cyanotoxins. The dynamics and toxin production of P. rubescens population in Lake Albano, a volcanic crater lake in Central Italy, has been studied for 5 years (January 2001-April 2005). Winter-spring superficial blooms with frequent scums were observed every year. Total microcystin (MC) levels were measured from April 2004 to October 2005 by liquid chromatography-tandem mass spectrometry. MC levels up to 14.2mug/l were measured, with high concentrations found in summer at a 20-25m depth. The intracellular toxin content varied between 1.5 (surface, January 2004) and 0.21pg/cell (surface, May 2004). Six different MCs were detected, the most abundant being two desmethyl-MC-RR isomers. Of the 13 water wells monitored in the Lake Albano area, two of them showed MC contamination during winter, confirming the ability of these toxins to migrate through groundwater towards public water sources. These results highlight the need for further studies on the mobility and fate of these pervasive cyanobacterial toxins.

Bacterial Toxins↗
PubMed2005

Acaricidal properties of the essential oil of Melaleuca alternifolia Cheel (tea tree oil) against nymphs of Ixodes ricinus.

The aim of the study was to examine the acaricidal effect of essential oil of Melaleuca alternifolia (tea tree oil, TTO) at different doses (4, 6, 8 and 10 microl) and for different exposure times (30, 60, 90 and 120 min) on nymphs of Ixodes ricinus. A dose of 8 microl TTO was lethal for more than 70% of ticks when inhaled and this effect was enhanced when the dose was increased to 10 microl (> 80%). The effect was correlated with the duration of exposure of ticks to TTO, with a significant effect being observed after 90 min exposure. The findings show that TTO has acaricidal properties and could be extremely useful in controlling ticks that are efficient vectors of pathogens.

Animals↗
PubMed2005

Antifungal activity of Lavandula angustifolia essential oil against Candida albicans yeast and mycelial form.

The antifungal activity of the essential oil of Lavandula angustifolia Mill. (lavender oil) and its main components, linalool and linalyl acetate, was investigated against 50 clinical isolates of Candida albicans (28 oropharyngeal strains, 22 vaginal strains) and C. albicans ATCC 3153. Growth inhibition, killing time and inhibition of germ tube formation were evaluated. The chemical composition of the essential oil was determined by gas chromatography and mass spectrometry. Lavender oil inhibited C. albicans growth: mean minimum inhibitory concentration (MIC) of 0.69% (vol./vol.) (vaginal strains) and 1.04% (oropharyngeal strains); mean MFC of 1.1% (vaginal strains) and 1.8% (oropharyngeal strains). Linalool was more effective than essential oil: mean MIC of 0.09% (vaginal strains) and 0.29% (oropharyngeal strains); mean MFC of 0.1% (vaginal strains) and 0.3% (oropharyngeal strains). Linalyl acetate was almost ineffective. Lavender oil (2%) killed 100% of the C. albicans ATCC 3153 cells within 15 min; linalool (0.5%) killed 100% of the cells within 30 s. The essential oil inhibited germ tube formation (mean MIC of 0.09%), as did the main components (MIC of 0.11% for linalool and 0.08% for linalyl acetate). Both the essential oil and its main components inhibited hyphal elongation of C. albicans ATCC 3153 (about 50% inhibition at 0.016% with each substance). Lavender oil shows both fungistatic and fungicidal activity against C. albicans strains. At lower concentrations, it inhibits germ tube formation and hyphal elongation, indicating that it is effective against C. albicans dimorphism and may thus reduce fungal progression and the spread of infection in host tissues.

Antifungal Agents↗
PubMed2004

Desmin-free cardiomyocytes and myocardial dysfunction in end stage heart failure.

Our aim was to evaluate the desmin content in the myocardial tissue of patients with end-stage heart failure of ischaemic origin and to assess its role on cardiac function. We studied 18 explanted hearts from patients transplanted for end-stage heart failure due to ischaemic cardiomyopathy (ICM). Control myocardial tissue was obtained from the cardiac biopsies of six women with breast cancer taken prior to commencing chemotherapy with anthracyclines, four male donors for heart transplantation and two autoptic hearts from patients who died due to non-cardiac events. Myocardial tissue, obtained from the left ventricle (remote zone from infarcted area), was analyzed by light and confocal immunochemistry (desmin) microscopy. The desmin content of myocardial tissue was obtained by real-time PCR. Cardiac function was evaluated by echocardiographic and right heart catheterization data, obtained before heart transplantation. Confocal microscopy evaluation showed a significant decrease in the number of desmin-positive myocytes (P<0.01) in ICM hearts compared to controls. At real-time PCR evaluation, there was a reduction (P<0.01) in desmin content in the ICM patients compared to controls. A negative correlation was found between desmin-free cardiomyocytes and ejection fraction (EF) (r=-0.834; P<0.02) on echocardiogram. A negative relationship (r=-0.688) was also found between desmin-negative myocytes and capillary wedge pressure. In conclusion, the myocardial tissue of patients with end-stage heart failure of ischaemic origin, shows a decreased number in desmin-positive myocytes at immunochemistry evaluation compared to normal individuals. This deficiency in cytoskeletal intermediate filament content is associated with reduced cardiac function.

Cardiomyopathy, Dilated↗
PubMed2003

Effects of gonadotropin-releasing hormone agonists on uterine volume and vasculature and on the immunohistochemical expression of basic fibroblast growth factor (bFGF) in uterine leiomyomas.

We investigated the effect of the GnRH agonist (GnRH-a) on the uterine volume and on the immunohistochemical expression of basic fibroblast growth factor (bFGF) and the vasculature of leiomyomas. Twenty-five women were treated with leuprorelin acetate for 3 months; 46 untreated patients were enrolled as a control group. The uterine volume was measured by ultrasonography. After myomectomy or hysterectomy, the immunoexpression of bFGF and the endothelial marker, CD34, was studied and compared in treated and untreated leiomyomas. Uterine volume decreased after therapy. The number of cells expressing bFGF and the vascularity were diminished in treated leiomyomas. Reduction in the blood supply might be responsible, in part, for uterine-volume shrinkage after GnRH-a therapy.

Adult↗
PubMed2001

Expression of the apoptosis inhibitor survivin in aggressive squamous cell carcinoma.

Deregulated expression of inhibitors of apoptosis (programmed cell death) may contribute to cancer by aberrantly extending cell viability and facilitating the insurgence of resistance to therapy. In this study, we investigated the potential expression and prognostic significance of the apoptosis inhibitor survivin in squamous cell carcinoma (SCC). A series of 135 cases of SCC including 46 oral SCC and 89 cutaneous SCC was analyzed for survivin expression by immunohistochemistry and Western blotting. Survivin was found in 57 cases (64%) of skin SCC and 26 cases (56%) of oral SCC, with weighted survivin scores ranging from 1 to 12. In contrast, normal oral epithelium, normal skin epithelium, and skin annexa did not express survivin. Survivin expression significantly (P < 0.05) segregated with high-grade and undifferentiated tumors with size >1.5 cm and invariably associated with lymph node metastasis. These data suggest that survivin expression may predictively identify cases of SCC with more aggressive and invasive clinical phenotype, potentially warranting closer follow-up protocols.

Apoptosis↗
PubMed2001

Effect of Helicobacter pylori infection on gastric cell proliferation and genomic instability in a paediatric population of southern Italy.

BACKGROUND: The incidence of gastric cancer is high in areas with a high prevalence of Helicobacter pylori infection. Cell transformation and tumour progression occur over a long period of time and markers of genomic instability usually precede morphological changes. AIM: To evaluate the effect of Helicobacter pylori infection on cell proliferation, DNA status and oncogene expression in children. PATIENTS AND METHODS: Morphometric and immunohistochemical techniques were used to analyse DNA content, p53 and c-myc oncogene expression and cell proliferation on gastric biopsies of 53 children (27 Helicobacter pylori-negative and 26 Helicobacter pylori-positive). RESULTS: Gastric mucosa was normal in 11% of Helicobacter pylori-positive and in 33% of Helicobacter pylori-negative subjects. Most children had chronic non-atrophic gastritis regardless of Helicobacter pylori infection, and only a minority of children affected by Helicobacter pylori had mild atrophic gastritis. Cell proliferation was significantly higher in children with Helicobacter pylori-positive gastritis than in those with Helicobacter pylori-negative gastritis. No metaplasia, dysplasia, p53 overexpression or altered DNA content was found in any child. Interestingly, 46% of children with and 29% without Helicobacter pylori infection had c-myc overexpression closely related to the cell proliferation rate. CONCLUSION: Helicobacter pylori infection in children may coexist with a normal gastric mucosa, and it is not associated with genomic instability markers in cases of chronic gastritis.

Adolescent↗
PubMed2001

In vitro activity of tea tree oil against Candida albicans mycelial conversion and other pathogenic fungi.

The antifungal activity of Melaleuca alternifolia Maiden (Myrtaceae) essential oil against yeasts (Candida spp., Schizosaccharomyces pombe, Debaryomyces hansenii) and dermatophytes (Microsporum spp. and Tricophyton spp.) is reported. We focused on the ability of tea tree oil to inhibit Candida albicans conversion from the yeast to the pathogenic mycelial form. Moreover we carried out broth microdilution test and contact tests to evaluate the killing time. M. alternifolia essential oil inhibited the conversion of C. albicans from yeast to the mycelial form at a concentration of 0.16% (v/v). The minimum inhibitory concentrations (MICs) ranged from 0.12% to 0.50% (v/v) for yeasts and 0.12% to 1% (v/v) for dermatophytes; the cytocidal activity was generally expressed at the same concentration. These results, if considered along with the lipophilic nature of the oil which enables it to penetrate the skin, suggest it may be suitable for topical therapeutic use in the treatment of fungal mucosal and cutaneous infections.

Anti-Infective Agents, Local↗
PubMed2001

[Long-term evaluation of the endoscopic treatment of gastric polyps].

BACKGROUND: The authors intend to evaluate the long-term efficacy of endoscopic treatment of gastric polyps. METHODS: They report their experience in 5000 upper gastro intestinal endoscopies performed between 1985 and 1998. The method used aimed to evaluate the distribution of polyps by sex and age, the frequency of various histological types and the incidence of complications in relation to histological type and the size of the polyps. The authors also analysed the indications and criteria of choice between endoscopic treatment and surgery and they calculated the incidence of malignant neoplasm and complications in relation to the endoscopic method used, as well as the incidence of relapse at the medium and long-term follow-up. They searched for the presence of neoplasms in the follow-up and compared their personal experience with data from international literature. RESULTS: The results obtained show that non-surgical treatment of gastric polyps is resolutive in most cases. The endoscopic resection of polyps was performed using a polypectomy loop. In patients converted to surgery, the necessity for the operation was caused by an unexpected hemorrhage that could not be controlled using endoscopic treatment. In this case, the operation consisted of resecting the entire wall of the lesion, including an extemporary histological analysis. CONCLUSIONS: The authors' experience allows them to state that endoscopic treatment of this gastric pathology is efficacious and free from risks and complications if stringent patient selection criteria are used (dimensions, morphological characteristics of the lesion) and control procedures over time suited to the potential malignancy of each histological type are carried out.

Adult↗
PubMed2001

MRP8, a new member of ABC transporter superfamily, identified by EST database mining and gene prediction program, is highly expressed in breast cancer.

BACKGROUND: With the completion of the human draft genome sequence, efforts are now devoted to identifying new genes. We have developed a computer-based strategy that utilizes the EST database to identify new genes that could be targets for the immunotherapy of cancer or could be involved in the multistep process of cancer. MATERIALS AND METHODS: Utilizing our computer-based screening strategy, we identified a cluster of expressed sequence tags (ESTs) that are highly expressed in breast cancer. Northern blot and reverse transcriptase polymerase chain reaction (RT-PCR) analyses demonstrated the tissue specificity of the computer-generated cluster and comparison with the human genome sequence assisted in isolating a full-length cDNA clone. RESULTS: We identified a new gene that is highly expressed in breast cancer. This gene is expressed at moderate levels in normal breast and testis and at very low levels in liver, brain, and placenta. The gene has two major transcripts of 4.5 kb and 4.1 kb. The 4.5-kb transcript is very abundant in breast cancer, and has an open reading frame of 1382 amino acids. The predicted protein sequence of the 4.5-kb transcript reveals that it has high homology with MRP5, a member of multidrug resistant-associated protein family (MRP). There are seven reported members in the MRP family; we designate this gene as MRP8 (ABCC11). The 4.5-kb MRP8 transcript consists of 31 exons and is located in a genomic region of over 80.4 kb on chromosome 16q12.1. The smaller 4.1-kb transcript of MRP8 is found in testis and may initiate within intron 6 of the gene. CONCLUSION: The selective expression of MRP8 (ABCC11), a new member of ATP-binding cassette transporter superfamily could be a molecular target for the treatment of breast cancer.

ATP-Binding Cassette Transporters↗
PubMed2000

Changes in myocardial cytoskeletal intermediate filaments and myocyte contractile dysfunction in dilated cardiomyopathy: an in vivo study in humans.

AIM: To investigate in vivo the intermediate cytoskeletal filaments desmin and vimentin in myocardial tissues from patients with dilated cardiomyopathy, and to determine whether alterations in these proteins are associated with impaired contractility. METHODS: Endomyocardial biopsies were performed in 12 patients with dilated cardiomyopathy and in 12 controls (six women with breast cancer before anthracycline chemotherapy and six male donors for heart transplantation). Biopsy specimens were analysed by light microscopy and immunochemistry (desmin, vimentin). Myocyte contractile protein function was evaluated by the actin-myosin in vitro motility assay. Left ventricular ejection fraction was assessed by echocardiography and radionuclide ventriculography. RESULTS: Patients with dilated cardiomyopathy had a greater cardiomyocyte diameter than controls (p < 0.01). The increase in cell size was associated with a reduction in contractile function, as assessed by actin-myosin motility (r = -0.643; p < 0.01). Quantitative immunochemistry showed increased desmin and vimentin contents (p < 0.01), and the desmin distribution was disturbed in cardiomyopathy. There was a linear relation between desmin distribution and actin-myosin sliding in vitro (r = 0.853; p < 0.01) and an inverse correlation between desmin content and ejection fraction (r = -0.773; p < 0.02). Negative correlations were also found between myocardial vimentin content and the actin-myosin sliding rate (r = -0.74; p < 0.02) and left ventricular ejection fraction (r = -0.68; p < 0.01). CONCLUSIONS: Compared with normal individuals, the myocardial tissue of patients with dilated cardiomyopathy shows alterations of cytoskeletal intermediate filament distribution and content associated with reduced myocyte contraction.

Actins↗
PubMed2000

Tyrosines 1015 and 1062 are in vivo autophosphorylation sites in ret and ret-derived oncoproteins.

Point mutations of the RET receptor tyrosine kinase are responsible for the inheritance of multiple endocrine neoplasia (MEN) type 2 syndromes and are also present in a fraction of sporadic medullary thyroid carcinomas. Somatic rearrangements of the RET gene generating the chimeric RET/papillary thyroid carcinoma (PTC) oncogenes are the predominant molecular lesions associated with papillary carcinoma, the most frequent thyroid malignancy in humans. Oncogenic mutations cause constitutive activation of the kinase function of RET, which, in turn, results in the autophosphorylation of RET tyrosine residues critical for signaling. In vitro kinase assays previously revealed six putative RET autophosphorylation sites. The aim of the present study was to assess the phosphorylation of two such residues, tyrosines 1015 and 1062 (Y1015 and Y1062), in the in vivo signaling of RET and RET-derived oncogenes. Using phosphorylated RET-specific antibodies, we demonstrate that both Y1015 and Y1062 are rapidly phosphorylated upon ligand triggering of RET. Moreover, regardless of the nature of the underlying activating mutation, the concomitant phosphorylation of Y1015 and Y1062 is a common feature of the various oncogenic RET products (MEN2A, MEN2B, and PTC). This study shows that Ab-pY1062 is a useful tool with which to detect activated RET in human tumor cells and surgical samples. Finally, the microinjection of Ab-pY1062 antibodies into living cells demonstrates that Ret/PTC1 signaling is required to maintain the mitogenesis of a human carcinoma cell line expressing the Ret/PTC1 oncoprotein.

Amino Acid Sequence↗
PubMed2000

Identification of a novel subtype of H4-RET rearrangement in a thyroid papillary carcinoma and lymph node metastasis.

RET/PTC chimeric oncogenes are generated by the fusion of heterologous genes to the RET tyrosine kinase encoding domain. These rearrangements are typical of papillary thyroid carcinomas. RET/PTC1 is one of the most frequently found RET/PTC version and, in all the cases so far reported, it is invariably generated by the fusion of the first encoding exon of the H4 gene to the RET kinase encoding domain. This results in the generation of an oncogenic protein containing the first 101 residues of the H4 protein at the N-terminus. We report the isolation of a novel subtype of H4-RET fusion, designated RET/PTC1L, from a human papillary carcinoma of the thyroid and lymph node metastasis. At variance with the classic one, this novel rearrangement generates a protein containing the N-terminal 150 residues of H4. RET/PTC1L is able to transform NIH 3T3 cells; its transforming ability, however, is 5-fold lower than that of the classic RET/PTC1 isoform. We propose that RET/PTC1L is a novel chimeric oncogene involved in thyroid tumorigenesis; its low transforming ability may be one of the reasons explaining the low frequency by which it is found in human thyroid carcinomas.

Carcinoma, Papillary↗
PubMed2000

Glial cell line-derived neutrotrophic factor and neurturin can act as paracrine growth factors stimulating DNA synthesis of Ret-expressing spermatogonia.

Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) are related growth factors which exert trophic effects on several neuronal populations and developing kidney. GDNF-family ligands interact with membrane receptors designated GFRalphas which, in turn, mediate stimulation of the Ret receptor tyrosine kinase. Here we show that Ret, GFRalpha-1 (the GDNF receptor), and GFRalpha-2 (the NTN receptor) are expressed by testicular germ cells, while GDNF and NTN are expressed by Sertoli cells. Both GDNF and NTN stimulate DNA synthesis in spermatogonia. Furthermore, Ret, ligands and co-receptors are expressed in germ cell tumors. Thus, GDNF-family ligands may act as paracrine factors in spermatogenesis and this circuit may be active in germ cell tumors.

Animals↗
PubMed1999

Modulation of in vivo growth of thyroid tumor-derived cell lines by sense and antisense vascular endothelial growth factor gene.

Vascular endothelial growth factor A (VEGF) is a potent mitogen for endothelial cells in vitro and promotes neo-angiogenesis in vivo. VEGF overexpression occurs in most human malignancies including thyroid carcinomas in which elevated VEGF expression is associated with a high tumorigenic potential. To investigate the role of VEGF in angiogenesis associated with development of thyroid carcinomas, we constitutively expressed VEGF121 into a poorly tumorigenic cell line (NPA) expressing minimal levels of endogenous VEGF. Here we report that VEGF overexpressing NPA cells showed the same growth potential as untransfected NPA in vitro but formed well-vascularized tumors when injected subcutaneously into nude mice with markedly reduced latency compared to parental cells. A complementary approach was to suppress VEGF expression in a highly tumorigenic anaplastic cell line (ARO) by the transfection of an antisense construct. Antisense-transfected ARO cells expressed reduced constitutive levels of VEGF, showed the same growth potential as untransfected ARO cells in vitro and formed small tumors characterized by minimal vascularization, extensive necrosis and longer latency compared to parental or vector-transfected ARO cells in vivo. Finally, we investigated the expression of both VEGF tyrosine kinase receptors (Flt-1 and Flk-1/KDR) in tumor specimens by RT - PCR. Expression of (Flt-1 and Flk-1/KDR) was low in tissue specimens derived from NPA tumors, but was found enhanced in NPA VEGF tumors; conversely, the expression of VEGF receptors was high in tissue specimens derived from ARO tumors but was decreased in tumors derived from VEGF depleted ARO cells. These results clearly demonstrate that VEGF indirectly promotes the growth of thyroid tumors by stimulating angiogenesis.

Animals↗
PubMed1999

galectin-1 and galectin-3 expression in human bladder transitional-cell carcinomas.

Galectin-1 and galectin-3 are galactoside-binding proteins involved in different steps of tumor progression and potential targets for therapy. We have investigated the expression of these galectins in 38 human bladder transitional-cell carcinomas of different histological grade and clinical stage and in 5 normal urothelium samples. Galectin-1 mRNA levels were highly increased in most high-grade tumors compared with normal bladder or low-grade tumors. Western blot and immuno-histochemical analysis of normal and neoplastic tissues revealed a higher content of galectin-1 in tumors. Galectin-3 mRNA levels were also increased in most tumors compared with normal urothelium, but levels were comparable among tumors of different histological grade.

Adult↗
PubMed1999

Different mutations of the RET gene cause different human tumoral diseases.

The RET gene encodes a tyrosine kinase receptor for neurotrophic molecules. RET is a conceptually valuable example of how different mutations of a single gene may cause different diseases. Gene rearrangements activate the oncogenic potential of RET in human thyroid papillary carcinomas. On the other side, different point mutations activate RET in familial multiple endocrine neoplasia syndromes. Finally, inactivating mutations of RET can be present in Hirschsprung's disease patients. The detailed knowledge of the specific RET mutations responsible for human tumors provides relevant tools for the clinical management of these diseases. Moreover, the recent discovery of the growth factors which in vivo stimulate its signaling may shed new light on the role played by RET in the development and differentiation of the central and peripheral nervous system.

Carcinoma, Papillary↗