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L Perego

Publications and source records attributed to L Perego.

At least 19 recordsLinked to original sources
PubMed2002

Autoantibodies against a 72-kDa ductal cell membrane glycoprotein in a patient affected by Sjögren's syndrome and gastric MALT lymphoma.

Sjögren's syndrome is a chronic autoimmune disease affecting exocrine glands, resulting in xerostomia and xerophthalmia. Lymphocytic infiltration and fibrosis of exocrine glands as well as the presence of autoantibodies against organ-specific and non-organ-specific antigens are the hallmarks of the disease. We investigated whether some patients affected by Sjögren's syndrome might have autoantibodies directed against epithelial duct cell membrane proteins. We screened sera from patients affected by Sjögren's syndrome by indirect immunofluorescence on monkey salivary gland sections and FG-Met-2 cells (a pancreatic carcinoma cell line with ductal features) for the presence of antisalivary duct antibodies. Positive sera were employed in immunoprecipitation experiments on (35)S-methionine in vivo labeled and surface-biotinylated FG-Met-2 cells. The serum of a patient affected by Sjögren's syndrome and gastric mucosa-associated lymphoid tissue (MALT) lymphoma gave positive and distinct membrane immunostaining on FG-Met-2 cells. Immunoprecipitation with the patient's serum from (35)S-methionine-labeled cell extracts followed by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and autoradiography showed the presence of autoantibodies against a 72-kDa protein. After biotin-surface labeling of FG-Met-2 cells, a band with identical electrophoretic mobility was immunoprecipitated by the serum, demonstrating that the 72-kDa band is a membrane glycoprotein. We demonstrated by three complementary approaches, i.e., immunocytochemistry, (35)S-methionine in vivo labeling, and cell surface biotinylation, the presence of autoantibodies directed against a duct cell membrane protein of 72-kDa in a patient affected by Sjögren's syndrome and gastric MALT lymphoma. Autoantibodies directed against this novel membrane autoantigen may be an additional serological marker in some cases of Sjögren's syndrome.

Aged↗
PubMed2002

Autoantibodies to amphiphysin I and amphiphysin II in a patient with sensory-motor neuropathy.

A proportion of patients with peripheral neuropathies has circulating autoantibodies directed against neural antigens. In some cases, autoantibodies may play a pathogenic role. We studied a patient with a progressive sensory-motor axonal neuropathy of unknown etiology, looking for circulating autoantibodies against neural antigens and we showed that the patient's serum contained anti-amphiphysin I (AMP I) and amphiphysin II (AMP II) autoantibodies. A sural nerve biopsy revealed an axonal neuropathy. Indirect immunofluorescence experiments with the patient's serum showed a staining of rat axons due to alpha-AMP I autoantibodies and a specific labelling of cytoplasm and Schmidt-Lanterman incisures of Schwann cells due to alpha-AMP II autoantibodies. In conclusion we identified a patient affected by a sensory-motor neuropathy with autoantibodies against both AMP I and AMP II.

Aged↗
PubMed2001

High glucose causes apoptosis in cultured human pancreatic islets of Langerhans: a potential role for regulation of specific Bcl family genes toward an apoptotic cell death program.

Type 2 diabetes is characterized by insulin resistance and inadequate insulin secretion. In the advanced stages of the disease, beta-cell dysfunction worsens and insulin therapy may be necessary to achieve satisfactory metabolic control. Studies in autopsies found decreased beta-cell mass in pancreas of people with type 2 diabetes. Apoptosis, a constitutive program of cell death modulated by the Bcl family genes, has been implicated in loss of beta-cells in animal models of type 2 diabetes. In this study, we compared the effect of 5 days' culture in high glucose concentration (16.7 mmol/l) versus normal glucose levels (5.5 mmol/l) or hyperosmolar control (mannitol 11 mmol/l plus glucose 5 mmol/l) on the survival of human pancreatic islets. Apoptosis, analyzed by flow cytometry and electron and immunofluorescence microscopy, was increased in islets cultured in high glucose (HG5) as compared with normal glucose (NG5) or hyperosmolar control (NG5+MAN5). We also analyzed by reverse transcriptase-polymerase chain reaction and Western blotting the expression of the Bcl family genes in human islets cultured in normal glucose or high glucose. The antiapoptotic gene Bcl-2 was unaffected by glucose change, whereas Bcl-xl was reduced upon treatment with HG5. On the other hand, proapoptotic genes Bad, Bid, and Bik were overexpressed in the islets maintained in HG5. To define the pancreatic localization of Bcl proteins, we performed confocal immunofluorescence analysis on human pancreas. Bad and Bid were specifically expressed in beta-cells, and Bid was also expressed, although at low levels, in the exocrine pancreas. Bik and Bcl-xl were expressed in other endocrine islet cells as well as in the exocrine pancreas. These data suggest that in human islets, high glucose may modulate the balance of proapoptotic and antiapoptotic Bcl proteins toward apoptosis, thus favoring beta-cell death.

Apoptosis↗
PubMed2000

Estrogens stimulate proliferation of intrahepatic biliary epithelium in rats.

BACKGROUND & AIMS: We investigated the expression of estrogen receptor (ER) alpha and beta subtypes in cholangiocytes of normal and bile duct-ligated (BDL) rats and evaluated the role and mechanisms of estrogens in the modulation of cholangiocyte proliferation. METHODS: ER-alpha and ER-beta were analyzed by immunohistochemistry, reverse-transcription polymerase chain reaction, and Western blotting in normal and BDL rats. The effects of the ER antagonists tamoxifen and ICI 182,780 on cholangiocyte proliferation were evaluated. RESULTS: Cholangiocytes expressed both ER-alpha and ER-beta subtypes, whereas hepatocytes expressed only ER-alpha. In association with a marked cholangiocyte proliferation and with enhanced estradiol serum levels, the immunoreactivity for ER-alpha involved a 3-fold higher percentage of cholangiocytes in 3-week BDL than in normal rats; immunoreactivity for ER-beta showed a 30-fold increase. Western blot analysis showed that during BDL, the total amount of ER-beta in cholangiocytes was markedly increased (5-fold), whereas that of ER-alpha decreased slightly (-25%). Treatment with tamoxifen or ICI 182,780 of 3-week BDL rats inhibited cholangiocyte proliferation and induced overexpression of Fas antigen and apoptosis in cholangiocytes. In vitro, 17 beta estradiol stimulated proliferation of cholangiocyte, an effect blocked to the same extent by tamoxifen or ICI 182,780. CONCLUSIONS: This study suggests that estrogens and their receptors play a role in the modulation of cholangiocyte proliferation.

Animals↗
PubMed2000

The function of alkaline phosphatase in the liver: regulation of intrahepatic biliary epithelium secretory activities in the rat.

We studied the effects of alkaline phosphatase (AP) on the secretory processes of the rat intrahepatic biliary epithelium as well as the role of the intrahepatic biliary epithelium in the uptake and biliary secretion of exogenous AP. The effects of acute and chronic administration of AP on bile secretory parameters were investigated in vivo in normal and bile duct ligated (BDL) rats and in vitro in isolated rat bile duct units (IBDU). In vivo, acute AP administration decreased bile flow and biliary bicarbonate excretion and abolished secretin choleresis in BDL rats but not in normal rats. On the contrary, the AP inhibitor, levamisole, increased in BDL rat bile flow and biliary bicarbonate excretion. In vitro, basal and secretin-stimulated Cl(-)/HCO(3)(-) exchanger activity in IBDU was immediately inhibited by AP intraluminal microinjection (apical exposure) but only after a prolonged exposure to the basolateral pole. Levamisole increased the Cl(-)/HCO(3)(-) exchanger activity of IBDU. A significant basolateral uptake of AP occurs in IBDU with a progressive transport to the apical domain. AP chronic treatment increased AP and gamma-glutamyltranspeptidase (gamma-GT) activities in the intrahepatic bile ducts and hepatocyte canalicular pole, promoted enlargement of bile canaliculi, and decreased bile flow and biliary bicarbonate excretion. In conclusion, the intrahepatic biliary epithelium plays a role in the uptake and biliary secretion of serum AP. AP inhibits the secretory processes of the intrahepatic biliary epithelium and induces features of intrahepatic cholestasis after chronic administration. These findings indicate that AP plays an active role in down-regulating the secretory activities of the intrahepatic biliary epithelium.

Alkaline Phosphatase↗
PubMed1999

Insulin and insulin-like growth factor-1 stimulate proliferation and type I collagen accumulation by human hepatic stellate cells: differential effects on signal transduction pathways.

Insulin and insulin-like growth factor (IGF-1) are mitogenic for fibroblasts and smooth muscle cells. IGF-1 increases in inflamed and fibrotic tissues and induces proliferation of rat hepatic stellate cells (HSC). This study evaluates the potential roles of these hormones in the development of liver fibrosis. Insulin and IGF-1 receptor expression was evaluated by immunohistochemistry in both cultured human HSC and human liver tissue. Phosphorylation of both 70-kd S6 kinase and extracellular-regulated kinase (ERK), cell proliferation, type I collagen gene expression, and accumulation in HSC culture media were evaluated by Western blot, immunohistochemistry for bromodeoxyuridine (BrdU), Northern blot, and enzyme-linked immunosorbent assay, respectively. Insulin and IGF-1 receptors were detected in HSC in vitro and in liver sections from patients with chronic active hepatitis. Insulin and IGF-1 induced 70-kd S6 kinase phosphorylation in HSC, whereas IGF-1 only induced ERK phosphorylation. Insulin and IGF-1 stimulated HSC proliferation in a dose-dependent fashion, with IGF-1 being four to five times more potent than insulin. Cell exposure to specific inhibitors showed that both phosphatidylinositol 3-kinase (PI3-K) and ERK are involved in IGF-1-induced mitogenesis, whereas insulin stimulated mitogenesis through a PI3-K-dependent ERK-independent pathway. IGF-1 increased type I collagen gene expression and accumulation in HSC culture media through a PI3-K- and ERK-dependent mechanism. In conclusion, insulin and IGF-1, which stimulate HSC mitogenesis and collagen synthesis, may act in concert to promote liver fibrosis in vivo by a differential activation of PI3-K- and ERK1-dependent pathways.

Androstadienes↗
PubMed1998

MSJ-1, a new member of the DNAJ family of proteins, is a male germ cell-specific gene product.

A cDNA encoding for a new member of the DnaJ protein family has been isolated by screening a mouse spermatogenic cell expression library. The full-length cDNA obtained by extension of the original clone with RT-PCR has been characterized with respect to its DNA sequence organization and expression. The predicted open reading frame encodes a protein of 242 amino acid residues whose sequence is similar to that of bacterial DnaJ proteins in the amino-terminal portion since it contains the highly conserved J domain which is present in all DnaJ-like proteins and is considered to have a critical role in DnaJ protein-protein interactions. In contrast, the middle and carboxyl-terminal regions of the protein are not similar to any other DnaJ proteins, with the exception of the human neuronal HSJ-1 with which displays a 48% identity in a 175-amino-acid overlap. Analysis of RNAs from a wide spectrum of mouse somatic tissues, including the brain, and from ovary and testis reveals that the gene is specifically expressed in testis only. Developmental Northern blot analysis of testis RNA from mice of different ages and in situ hybridization on juvenile and adult testis sections demonstrate that the mRNA is first transcribed in spermatids. A similar pattern of expression is exhibited also in rat testis. Based upon all these observations, we have named this novel mouse gene, MSJ-1, for mouse sperm cell-specific DNAJ first homolog.

Age Factors↗
PubMed1998

Molecular cloning and developmental pattern of expression of MSJ-1, a new male germ cell-specific DNAJ homologue.

A cDNA encoding a new member of the DnaJ protein family has been isolated by screening a mouse testicular expression library. The predicted protein, named MSJ-1, is 242 amino acid residues-long, containing the fingerprinting J domain in the NH2 terminus. A wide tissutal Northern blot analysis reveals that MSJ-1 is expressed only in the testis, while in situ hybridization analyses demonstrate that the mRNA is first transcribed in spermatids. The antiserum developed against a MSJ-1/GST fusion protein recognizes a protein of 30 kDa in germ cell protein extracts.

Amino Acid Sequence↗
PubMed1997

Molecular cloning and tissue-specific expression of the mouse homologue of the rat brain 14-3-3 theta protein: characterization of its cellular and developmental pattern of expression in the male germ line.

The highly conserved 14-3-3 family of proteins, originally reported as brain-specific and then found in various somatic cells and oocytes, interacts with several important signal transduction kinases so that actually the 14-3-3 protein are considered as modulators of multiple signal transduction pathways. Here we show that a 14-3-3 protein is also expressed in the male germ cells, thus extending the protein cellular distribution to a cell line never reported to express 14-3-3 proteins. Screening of a mouse spermatogenic cells lambda gt11 cDNA library with affinity-purified polyclonal antibodies to the tyrosine kinase SP42 allowed the isolation of several positive clones. Sequencing of a positive cDNA clone revealed a 735-nucleotide open reading frame encoding a protein of 245 amino acids (27,778 Da). The predicted protein was found to be identical to the most recently discovered 14-3-3 isoform, the theta subtype from a rat brain. Here we demonstrate that 14-3-3 theta mRNA is highly expressed in testis and brain only. Western immunoblot analyses confirm the Northern blot data. Developmental Northern and Western blot analyses are consistent with an expression and translation of the 14-3-3 theta gene throughout spermatogenesis. However, analysis of RNA from purified populations of spermatogenic cells at different developmental stages and immunohistochemistry on adult testis sections reveal that within the testis the 14-3-3 theta gene products are most abundant in meiotic prophase spermatocytes, and, above all, in differentiating spermatids. Both testicular and epididymal spermatozoa are negative. The present study is the first report on the presence and molecular characterization of the 14-3-3 theta gene product in the male germ line. Our observations suggest that this specific member of the 14-3-3 protein family could play distinct modulatory roles in the complex development of the mammalian male germ cell lineage.

14-3-3 Proteins↗
PubMed1996

Structure and macromolecular composition of the zebrafish egg chorion.

The chorion is the acellular envelope surrounding mature eggs of teleostean fish. The macromolecular composition of the zebrafish (Danio rerio) egg chorion, organised as a three-layered structure, has been analysed. SDS-PAGE analysis, under reducing conditions, of isolated and purified chorions revealed a reproducible pattern of four major polypeptides (116, 97, 50 and 43 kDa) and several minor bands. Lectin binding assays showed that both the 116 kDa and 50 kDa proteins were recognised by concanavalin agglutinin (Con A), Galanthus nivalis agglutinin (GNA), Sambucus nigra bark agglutinin (SNA) and Ricinus communis agglutinin (RCA 120), suggesting that these polypeptides are N-linked glycoproteins. By contrast, neither the 97 kDa nor the 43 kDa polypeptides were stained by these lectins, indicating that these polypeptides are not glycosylated. Amino acid analysis also showed significant differences in the average content of some amino acids, for example serine and proline, when compared with previous reports.

Amino Acids↗
PubMed1996

Biological monitoring of genotoxic hazard in workers of the rubber industry.

Biological monitoring of genotoxic hazard in the rubber industry was performed in 19 male workers and 20 age-matched controls in a local health unit in northern Italy. Peripheral blood lymphocytes were analyzed for the presence of DNA damage (single-cell microgel-electrophoresis, or comet assay) and for cytogenetic parameters (sister chromatid exchanges and micronuclei frequency, and proliferative rate index). The following bioassays were performed in urine samples: a) mutagenicity test and concentration of thioethers as markers of exposure, and b) excretion of D-glucaric acid and 6-beta-hydroxycortisol (related to 17-hydroxycorticosteroid excretion) as indicators of the inductive status of the microsomal enzyme system (phase-I). The exposed subjects showed statistically higher mean values of 17-hydroxycorticosteroids and micronuclei and lower values of 6-beta-hydroxycortisol than controls, when taking cigarette smoking into account. The comet assay showed higher values for migration distance in exposed subjects than controls, although the differences were not significant at a p-value of 0.05. These findings suggest that industrial exposure in the rubber processing industry may cause genetic damage and may modify the activity level of some enzymes; these results should be considered with caution due to the small number of subjects enrolled.

Adult↗
PubMed1988

Tuberoinfundibular dopaminergic function in Parkinson's disease.

A deficit of nigrostriatal, mesocortical and mesolimbic dopamine systems in Parkinson's disease is well known. We know less about the involvement of tuberoinfundibular dopamine (TID) systems. In untreated (naive or wash-out) men with Parkinson's disease, we studied TID function through basal and stimulated plasma levels of growth hormone, prolactin and thyrotropin. Only minor abnormalities in prolactin responses to thyrotropin-releasing hormone were found, probably reflecting denervation hypersensitivity. TID function is preserved in men with Parkinson's disease.

Aged↗
PubMed1988

Neuroendocrinological function in Alzheimer's disease.

The neuroendocrine function is regulated by several neurotransmitters (acetylcholine, dopamine, somatostatin and noradrenaline) known to be reduced in brains of patients with Alzheimer's disease (AD). Moreover, the hypothalamus also has pathological changes. In spite of these findings suggesting neuroendocrine dysfunctions, this function has seldom been investigated in AD patients so far. We have compared patients with clinically 'probable' AD of mild-to-moderate severity with nondemented age- and sex-matched controls. Plasma levels of prolactin (PRL), growth hormone (GH) and thyroid-stimulating hormone (TSH) were measured by commercially available radioimmunoassays (RIA) before and after stimulation with metoclopramide, l-dopa or thyrotropin-releasing hormone. Basal plasma levels of beta-endorphin and beta-lipotropin were measured by RIA after high-performances liquid chromatography. Basal and stimulated plasma levels of PRL, GH, TSH and beta-lipotropin were similar in the two groups. Basal lamina levels of beta-endorphin were significantly higher in the patient group. Of doubtful clinical importance, this might be attributed to decreased tuberoinfundibular dopaminergic activity and has also been seen in patients with Parkinson's disease.

Aged↗
PubMed1984

Effects of long-term antiepileptic therapy on the hypothalamic-pituitary axis in man.

Effects of long-term antiepileptic therapy on the hypothalamic-pituitary axis were evaluated from the basal and stimulated plasma levels of growth hormone (GH) and prolactin (PRL) and from circadian adrenocorticotropic hormone (ACTH)/cortisol rhythms. Data for patients with well-controlled epilepsy of mild-to-moderate severity were compared with those for normal healthy volunteers. Analysis of the effects of each antiepileptic drug (AED) and of combined AEDs revealed minor abnormalities of stimulated GH secretion in all treated patients. In epileptic men, all individual AEDs (except valproate) and AED polytherapy increased both basal and stimulated plasma levels of PRL. In epileptic women, this effect was more variable and less marked, probably because of early depletion of PRL reserves. Each AED and combined AEDs did not significantly change circadian ACTH/cortisol rhythms in epileptic patients. The effects observed seem not to be related to epilepsy per se. Clinical implications, pathways, and neurotransmitters involved and possible mechanisms of the neuroendocrine effects of long-term AED therapy are discussed.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Insulin-secreting pituitary GH3 cells: a potential beta-cell surrogate for diabetes cell therapy.

In a companion article, we describe the engineering and characterization of pituitary GH3 cell clones stably transfected with a furin-cleavable human insulin cDNA (InsGH3 cells). This article describes the performance of InsGH3 (clones 1 and 7) cell grafts into streptozotocin (STZ)-induced diabetic nude mice. Subcutaneous implantation of 2 x 10(6) InsGH3 cells resulted in the progressive reversal of hyperglycemia and diabetic symptoms, even though the progressive growth of the transplanted cells (clone 7) eventually led to glycemic levels below the normal mouse range. Proinsulin transgene expression was maintained in harvested InsGH3 grafts that, conversely, lose the expression of the prolactin (PRL) gene. Elevated concentrations of circulating mature human insulin were detected in graft recipients, demonstrating that proinsulin processing by InsGH3 cells did occur in vivo. Histologic analysis showed that transplanted InsGH3 grew in forms of encapsulated tumors composed of cells with small cytoplasms weakly stained for the presence of insulin. Conversely, intense insulin immunoreactivity was detected in graft-draining venules. Compared to pancreatic betaTC3 cells, InsGH3 cells showed in vitro a higher rate of replication, an elevate resistance to apoptosis induced by serum deprivation and proinflammatory cytokines, and significantly higher antiapoptotic Bcl-2 protein levels. Moreover, InsGH3 cells were resistant to the streptozotocin toxicity that, in contrast, reduced betaTC3 cell viability to 50-60% of controls. In conclusion, proinsulin gene expression and mature insulin secretion persisted in transplanted InsGH3 cells that reversed hyperglycemia in vivo. InsGH3 cells might represent a potential beta-cell surrogate because they are more resistant than pancreatic beta cells to different apoptotic insults and might therefore be particularly suitable for encapsulation.

Animals↗