Biomedical subjects

C Pasquali

Publications and source records attributed to C Pasquali.

At least 19 recordsLinked to original sources

PubMed2000

Analysis of glycosyl phosphatidylinositol-anchored proteins by two-dimensional gel electrophoresis.

The aim of this study was to characterize mammalian glycosyl phosphatidylinositol (GPI)-anchored proteins y two-dimensional gel electrophoresis using immobilized pH gradients. Analysis was performed on detergent-resistant membrane fractions of baby hamster kidney (BHK) cells, since such fractions have previously been shown to be highly enriched in GPI-anchored proteins. Although the GPI-anchored proteins were readily separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), these proteins were undetectable on two-dimensional (2-D) gels, even though these gels unambiguously revealed high enrichment of known hydrophobic proteins of detergent-resistant membranes such as caveolin-1 and flotillin-1 (identified by Western blotting and tandem mass spectrometry, respectively). Proper separation of GPI-anchored proteins required cleavage of the lipid tail with phosphatidylinositol-specific phospholipase C, presumably to avoid interference of the hydrophobic phospholipid moiety of GPI-anchors during isoelectric focusing. Using this strategy, BHK cells were observed to contain at least six GPI-anchored proteins. Each protein was also present as multiple isoforms with different isoelectric points and apparent molecular weights, consistent with extensive but differential N-glycosylation. Pretreatment with N-glycosidase F indeed caused the different isoforms of each protein to collapse into a single spot. In addition, quantitative removal of N-linked sugars greatly facilitated the detection of heavily glycosylated proteins and enabled sequencing by nanoelectrospray-tandem mass spectrometry as illustrated for the GPI-anchored protein, Thy-1.

Amino Acid Sequence↗

PubMed2000

Mapping and identification of protein-protein interactions by two-dimensional far-Western immunoblotting.

Studies of protein-protein interactions have proved to be a useful approach to link proteins of unknown function to known cellular processes. In this study we have combined several existing methods to attempt the comprehensive identification of substrates for poorly characterized human protein tyrosine phosphatases (PTPs). We took advantage of so-called "substrate trapping" mutants, a procedure originally described by Flint et al. (Proc. Natl. Acad. Sci. USA 1997, 94, 1680-1685) to identify binding partners of cloned PTPs. This procedure was adapted to a proteome-wide approach to probe for candidate substrates in cellular extracts that were separated by two-dimensional (2-D) gel electrophoresis and blotted onto membranes. Protein-protein interactions were revealed by far-Western immunoblotting and positive binding proteins were subsequently identified from silver-stained gels using tandem mass spectrometry. With this method we were able to identify possible substrates for PTPs without using any radio-labeled cDNA or protein probes and showed that they corresponded to tyrosine phosphorylated proteins. We believe that this method could be generally applied to identify possible protein-protein interactions.

Adenocarcinoma↗

PubMed2000

ME-PCR for the identification of mutated K-ras in serum and bile of pancreatic cancer patients: an unsatisfactory technique for clinical applications.

Our aim was to assess the clinical reliability of mutated K-ras detection in serum or bile for the diagnosis of pancreatic cancer using ME-PCR. DNA was extracted from 1 ml serum obtained from 29 patients with pancreatic cancer and 12 control subjects. ME-PCR was optimized using a mixture of normal DNA added with different amounts of mutated DNA. The analysis of sera obtained from the 29 patients and of bile obtained from 11 pancreatic cancer patients demonstrated the presence of mutated K-ras in two (6.9%) and four cases (36%). By contrast K-ras was not amplifiable in any of the 12 serum samples obtained from healthy controls. In conclusion the DNA obtained from pancreatic cancer patients' sera is suitable for K-ras amplification and for the identification of codon 12 point mutations. However ME-PCR alone has an unsatisfactory sensitivity for the detection of pancreatic cancer using serum DNA as starting template.

Adult↗

PubMed2000

Median pancreatectomy for tumors of the neck and body of the pancreas.

BACKGROUND: When enucleation is too risky because of possible damage of the main pancreatic duct, benign tumors located in the neck or body of the pancreas are usually removed by a left (spleno)-pancreatectomy or by a pancreatoduodenectomy. But standard pancreatic resection results in an important loss of normal pancreatic parenchyma and may cause impairment of exocrine and endocrine function. The aim of this study was to evaluate early and longterm results of median pancreatectomy, a limited resection of the midportion of the pancreas, in selected patients with benign or borderline tumors of the pancreas. STUDY DESIGN: Records of patients at Ospedale Busonera between November 1985 and September 1998 were reviewed. Ten patients with tumors of the neck or body of the pancreas underwent median pancreatectomy; the cephalic stump was sutured and the distal stump was anastomosed with a Roux-en-Y jejunal loop. Followup included clinical evaluation and routine laboratory tests: abdominal ultrasonography, exocrine and endocrine pancreatic function with fecal chymotrypsin, and an oral glucose tolerance test. RESULTS: Pathologic examination showed: insulinoma (n = 3), mucinous cystadenoma (n = 3), nonfunctioning endocrine tumor (n = 1), papillary-cystic neoplasm (n= 1), serous cystadenoma (n = 1), and intraductal mucinous tumor (n = 1). Operative mortality and morbidity were 0% and 40%, respectively; pancreatic fistula occurred in three patients. At mean followup of 62.7 months, no recurrence was found and no patient had exocrine insufficiency or glucose metabolism impairment. CONCLUSIONS: Median pancreatectomy is a safe and effective alternative to major pancreatic resection in selected patients with benign or low-malignant lesions of the pancreas. This procedure carries a surgical risk similar to that of the standard operation, but avoids extensive pancreatic resection and pancreatic function impairment.

Adolescent↗

PubMed2000

Macrocystic serous cystadenoma of the pancreas: clinicopathologic features in seven cases.

BACKGROUND: Serous cystic neoplasms of the pancreas are uncommon tumors classified as microcystic adenomas. In this article, the authors report clinico-pathologic features of seven cases of macrocystic variant of the serous cystadenoma. METHODS: Seven patients (5 females and 2 males) with a diagnosis of cystic lesion of the pancreas were observed after 1995. Clinical, radiological, and pathologic features, including immunohistochemistry, were reported. Enzymes and tumor markers CEA, CA 19-9, CA 125, CA 15-3, CA 72-4, and mucin-like carcinoma-associated antigen (MCA) were investigated in the serum and cyst fluid of the patients. Cytology was also performed. RESULTS: Six patients were symptomatic complaining abdominal pain. All cases had radiologic evidence of unilocular cyst of the pancreas. The suspected diagnosis was consistent with mucinous cystic neoplasm. Serum tumor markers were all in the normal range. After surgery, pathology showed in all cases a cyst lined with cuboidal, periodic acid-Schiff (PAS)-positive epithelium, without mucin content or atypia. Minute microcysts were found surrounding the main cavity. Immunohistochemical stains were positive for cytokeratin, CA19-9, CA15-3, CA 72-4, and MCA. CEA was unexpressed. CA 125 in the cyst fluid were found elevated in three cases and CA 19-9 in three cases. Cytology was negative in all cases. CONCLUSION: When a unilocular pancreatic cyst is found, without history of pancreatitis and gallstones, having low serum tumor markers levels and negativity of CA 72-4 and MCA in the cyst fluid, the diagnosis of the macrocystic variant of the serous cystadenoma may be suggested. At present, the diagnosis is still based on pathological examination after cyst removal.

Adult↗

PubMed1999

Identification of syntenin as a protein of the apical early endocytic compartment in Madin-Darby canine kidney cells.

We used flow cytometry to sort and analyze apical and basolateral endocytic vesicles from filter-grown Madin-Darby canine kidney (MDCK) cells after membrane internalization of the lipophilic fluorescent probe trimethylamino-diphenylhexatriene. Western blot analysis of sorted fractions showed enrichment of the early endosomal markers transferrin receptor and the small GTPase Rab5. Two-dimensional gel analysis indicated that the apical and basolateral early endosomes differed significantly in their protein composition. We found nine polypeptides to be specifically enriched in apical or basolateral endocytic vesicles. An apical protein identified by microsequencing was the adaptor molecule syntenin. This protein contains two PDZ domains (PSD-95, Dlg, and ZO-1 homology) that bind syndecan and ephrin-B2 cytoplasmic domains. In MDCK cells, transiently overexpressed Myc-tagged syntenin localized to both plasma membrane domains and to an intracellular vesicular compartment. Syntenin positive vesicles colocalized with internalized transferrin in the perinuclear region. In addition, syntenin colocalized in the apical supranuclear region with Rab5 and Rab11; the latter is a marker for the apical recycling endosomes in MDCK cells.

Amino Acid Sequence↗

PubMed1999

Subcellular fractionation, electromigration analysis and mapping of organelles.

Subcellular fractionation has provided the means required to analyze the composition and properties of purified cellular elements. In particular, subcellular fractionation has helped to define membrane boundaries and became necessary for the development of cell-free assays that reconstitute complicated cellular processes. Although cell fractionation techniques have improved over the last decades the purification of organelles to homogeneity is still a barely accessible goal in cell biology. In this article, we will first briefly review the basic principles of subcellular fractionation, and the establishment of different organelle fractions by density centrifugation, using tissue culture cells as a paradigm. Then we will discuss some of the intrinsic problems and will compare gradient purification of cellular extracts with electromigration analysis. Finally, we will describe alternative approaches, such as immunoisolation and flow cytometry to purify organelles from tissue culture cells.

Cell Fractionation↗

PubMed1999

Loss of epithelial polarity is accompanied by differential association of proteins with intracellular membranes.

Cellular membranes play an important role in the formation and maintenance of epithelial polarity, which is lost early during carcinogenesis. We set out to identify membrane proteins which are altered during loss of cell polarity in mammary epithelium. As a model system we used murine mammary epithelial cells expressing the conditional oncoprotein c-JunER, which induces a reversible loss of polarity upon beta-estradiol-driven activation [1]. When grown either in the absence or presence of hormone, these cells exhibit a polarized or unpolarized phenotype, respectively. Different membrane fractions of polarized or unpolarized cells were analyzed by two-dimensional electrophoresis (2-DE) and differentially expressed membrane proteins were identified. To distinguish between transmembrane orientation and peripheral attachment of these proteins, were performed extractions with carbonate at high pH or with Triton X-114. In addition, cytosolic proteins of both states were analyzed to investigate their differential association with distinct membrane fractions. We found ten protein spots preferentially or exclusively in polarized cells and 17 other proteins as being upregulated during loss of polarity. Some of the peripheral membrane proteins were identified by microsequencing. The resident Golgi protein nucleobindin and fructose-bisphosphate aldolase were preferentially associated with membranes of polarized cells, whereas alphaB crystallin was detected exclusively and in high amounts in unpolarized cells.

Animals↗

PubMed1999

General aspects of surgical treatment of pancreatic cancer.

BACKGROUND: Different results and opinions exist concerning the use of a standard or an extended lymphadenectomy, and about the indications for portal vein resection in the surgical treatment of pancreatic cancer. The site of recurrence of pancreatic cancer may help to define the usefulness of different treatments in avoiding local and/or distant recurrences. METHODS: From personal experience and a literature review, 841 patients who underwent portal vein resection were collected, and 29 papers reporting the results of extended lymphadenectomy in the surgical treatment of pancreatic cancer were analyzed. A review of the site of relapse according to the surgical treatment, with or without various adjuvant treatments, was performed. Personal experience on survival rate according to the site of relapse (local, distant, local and distant) is also reported. RESULTS: Portal vein resection has been performed without a significant increase in morbidity and mortality rate in a large number of patients. However, its usefulness for increasing the resectability rate and the long-term survival has yet to be established. Extended lymphadenectomy does not increase the morbidity and mortality rate, but conflicting results on long-term survival have been reported. Distant metastases, undetectable by the radiologist and the surgeon, usually kill more than 40% of the resected patients within 12 months. Only lymph node-positive patients with limited undetectable distant metastases seem to benefit from an extended lymphadenectomy. Although many data are lacking, the incidence of the different sites of relapse is the same whatever the surgical and/or adjuvant treatment performed. Overall survival and disease-free survival rate are not affected by the site of relapse. A significantly worse survival rate was observed after the radiological detection of local and distant metastasis than after an only local or only distant metastasis. CONCLUSION: Portal vein resection and extended lymphadenectomy can be performed without increasing the surgical morbidity and mortality rate. We still have insufficient data to decide which patient can benefit from a more extended procedure. Standardization of operations, terminology, pathological reporting, and follow-up, together with well-designed prospective studies, will help to decide the operation of choice for pancreatic cancer.

Humans↗

PubMed1998

Neisseria gonorrhoeae porin modulates phagosome maturation.

The porin (PorB) of Neisseria gonorrhoeae has been implicated in the pathogenesis of this species. Porin is believed to translocate from the bacterial outer membrane into target cell membranes affecting various cell functions. Here we investigated the effect of porin on phagosome maturation. Phagocytosis of latex beads by human macrophages was allowed in the presence or absence of purified porin. Isolation of latex bead-containing phagosomes and subsequent two-dimensional gel electrophoresis revealed substantial differences in the phagosomal protein composition. Immunoblotting detected higher amounts of annexin II and the early endocytic markers Rab5 and transferrin receptor and decreased levels of the late endocytic markers Rab7 and cathepsin D in phagosomes obtained in the presence of porin compared with those obtained in its absence. Furthermore, association of Rab4 with the latex bead-containing phagosomes was revealed by flow cytometry. The amount of this small GTPase was markedly higher in the phagosomes isolated in the presence of porin. The data thus indicate that neisserial porin is itself able to arrest phagosome maturation within macrophages.

Bacterial Outer Membrane Proteins↗

PubMed1998

Neuroendocrine tumor imaging: can 18F-fluorodeoxyglucose positron emission tomography detect tumors with poor prognosis and aggressive behavior?

We evaluated the clinical value of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) for neuroendocrine tumor (NET) detection. Sixteen patients with cytologically or histologically proved NETs were investigated. Patients were divided in two groups of eight patients each according to the clinicopathologic features related to prognosis: slow-growing NETs and aggressive NETs. Results of FDG tumor uptake as detected by PET were compared with computed tomography (CT) scans and with scans obtained with 111In-octreotide scintigraphy (n = 13). Tumor FDG uptake was increased in the primary lesion of all eight aggressive NETs; the tracer was shown also in lymph nodes, liver metastases, or both in five of six of them (83%). In four cases, additional unknown tumor sites undetected by CT scan were identified. A slight positivity was found in only one of eight cases with a slow-growing NET. The overall octreotide scintiscan sensitivity was 85%, but in the aggressive NETs it failed to detect the primary lesion in two of seven cases. Uptake of the tracer in some but not all tumor lesions in the same patient was seen by both FDG-PET and octreotide scintiscans. From our limited experience 18F-FDG PET seems to be useful for identifying NETs characterized by rapid growth or aggressive behavior. Uptake of the FDG tracer by the tumor may be related to a worse prognosis. Despite the heterogeneity of tracer uptake in the various lesions of NETs with multiple tumor sites, FDG-PET was able to detect unsuspected distant metastases, contributing to better staging of advanced disease.

Adult↗

PubMed1998

Portal but not peripheral serum levels of interleukin 6 could interfere with glucose metabolism in patients with pancreatic cancer.

UNLABELLED: Interleukin 6 (IL-6), an autocrine growth factor for many tumors, seems to favour tumor spread to the liver. Our aims were first to evaluate the pattern of portal and systemic IL-6 levels in patients with pancreatic cancer (PC, n = 18) and chronic pancreatitis (CP, n = 22) compared with controls (CS, n = 20); and second, to ascertain whether there was any relation between IL-6 levels and tumor spread or PC-associated Diabetes mellitus. For all subjects, a fasting serum sample was obtained from a cubital vein; a portal serum sample was obtained from nine PC and three CP patients. In cubital and portal sera we measured IL-6, interleukin 1 beta (IL-1b), CA 19-9, c-reactive protein (CRP) and amylase. Systemic IL-6 levels were significantly higher in PC patients than in CS. In PC, portal IL-6 levels were significantly higher than the corresponding systemic values. The same pattern was found in the three CP patients, whereas IL-1b, CA 19-9, CRP and amylase portal levels were the same as systemic values. No correlation was found between PC stage and systemic or portal IL-6 levels. Portal IL-6 levels were correlated with the corresponding fasting serum glucose values. A significant correlation was found between IL-6 values and CRP, ALT, total bilirubin, GGT and creatinine, but not amylase. IN CONCLUSION: (1) Portal IL-6, which is partly of pancreatic origin, is first metabolised in the liver; (2) Systemic IL-6 reflects hepatic and renal functions rather than local conditions in the pancreas; (3) IL-6 does not appear to influence PC spread; (4) IL-6, which is released in large amounts by the inflamed pancreas, may contribute to determining diabetes, thus interfering with the signal transducing pathways involved in glucose metabolism in liver cells.

Aged↗

PubMed1998

Standard versus extended lymphadenectomy associated with pancreatoduodenectomy in the surgical treatment of adenocarcinoma of the head of the pancreas: a multicenter, prospective, randomized study. Lymphadenectomy Study Group.

OBJECTIVE: The study was conducted to determine whether the performance of an extended lymphadenectomy and retroperitoneal soft-tissue clearance in association with a pancreatoduodenal resection improves the long-term survival of patients with a potentially curable adenocarcinoma of the head of the pancreas. SUMMARY BACKGROUND DATA: The usefulness of performing an extended lymphadenectomy and retroperitoneal soft-tissue clearance in conjunction with a pancreatoduodenal resection in the treatment of ductal adenocarcinoma of the head of the pancreas is still unknown. Published studies suggest a benefit for the procedure in terms of better long-term survival rates; however, these studies were retrospective or did not prospectively evaluate large series of patients. MATERIALS AND METHODS: Eighty-one patients undergoing a pancreatoduodenal resection for a potentially curable ductal adenocarcinoma of the head of the pancreas were randomized to a standard (n = 40) or extended (n = 41) lymphadenectomy and retroperitoneal soft-tissue clearance in a prospective, multicentric study. The standard lymphadenectomy included removal of the anterior and posterior pancreatoduodenal, pyloric, and biliary duct, superior and inferior pancreatic head, and body lymph node stations. In addition to the above, the extended lymphadenectomy included removal of lymph nodes from the hepatic hilum and along the aorta from the diaphragmatic hiatus to the inferior mesenteric artery and laterally to both renal hila, with circumferential clearance of the origin of the celiac trunk and superior mesenteric artery. Patients did not receive any postoperative adjuvant therapy. RESULTS: Demographic (age, gender) and histopathologic (tumor size, stage, differentiation, oncologic clearance) characteristics were similar in the two patient groups. Performance of the extended lymphadenectomy added time to the procedure, although the difference did not reach statistical significance (397 +/- 50 minutes vs. 372 +/- 50 minutes, p > 0.05). Transfusion requirements, postoperative morbidity and mortality rates, and overall survival did not differ between the two groups. When subgroups of patients were analyzed, using an a posteriori analysis that was not planned at the time of study design, there was a significantly (p < 0.05) longer survival rate in node positive patients after an extended rather than a standard lymphadenectomy. The survival curve of node positive patients after an extended lymphadenectomy could be superimposed onto the curves of node negative patients. Survival curves in node negative patients did not differ according to the magnitude of the lymphadenectomy. Multivariate analysis of all patients showed that long-term survival was affected by tumor differentiation (well vs. moderately vs. poorly differentiated, p > 0.001), diameter (< or = 2.0 cm. vs. > 2.0 cm., p < 0.01), lymph node metastasis (absent vs. present, p < 0.01) and need for 4 or more units of transfused blood (< 4 vs. > or = 4, p <0.01). CONCLUSIONS: The addition of an extended lymphadenectomy and retroperitoneal soft-tissue clearance to a pancreatoduodenal resection does not significantly increase morbidity and mortality rates. Although the overall survival rate does not differ in the two groups, there appears to be a trend toward longer survival in node positive patients treated with an extended rather than a standard lymphadenectomy.

Adenocarcinoma↗

PubMed1998

Transforming growth factor beta, fibrogenesis and hyperglycemia in patients with chronic pancreatitis.

UNLABELLED: It has been suggested that transforming growth factor beta (TGFb) mediates liver fibrosis, which can be monitored by the serum determination of the N-terminal peptide of type III procollagen (PIIIP) and laminin. Fibrosis is also an important phenomenon in patients with chronic pancreatitis (CP). In 23 patients with CP, 38 with liver cirrhosis (LC) and 20 healthy controls we compared the serum patterns of PIIIP, laminin and TGFb and assessed whether in CP these markers are correlated with exocrine and endocrine function. In patients with LC, PIIIP and laminin levels were significantly higher, whereas TGFb levels were significantly lower than those of controls. In CP patients, no significant variations were found for PIIIP and laminin, although levels were high in 7/23 and in 5/23 patients, respectively. TGFb levels in CP patients were higher than those in LC patients, levels being raised in 6/23 patients. In LC patients an inverse correlation was found between PIIIP and TGFb, whereas in CP patients, a direct correlation was found between TGFb and PIIIP. Moreover, in CP patients, there was also a positive correlation between TGFb and fasting serum glucose levels, while laminin was correlated with PABA test results. IN CONCLUSION: serum biochemical markers of liver fibrosis can be considered of limited value in assessing pancreatic fibrosis; in liver cirrhosis there may be a negative feed-back regulation between TGFb production and the fibrogenetic process; and in chronic pancreatitis TGFb appears to favor fibrosis on the one hand and the development of hyperglycemia on the other.

Adult↗

PubMed1997

Two-dimensional gel electrophoresis analysis of endovacuolar organelles.

Cells perform their multiple functions with the aid of a series of distinct membrane organelles. In the last years, many of these compartments have been isolated, purified, and extensively studied. The major roles of each organelle in the cell are well understood. However, most of the molecular basis by which they perform their functions is poorly known. The recent identification and study of a handful of proteins associated with endovacuolar compartments has had a major impact on the understanding of the molecular details of organelle functions even though two-dimensional (2-D) gel analysis indicates that hundreds of proteins are typically associated with a complex organelle. This shows that many details and surprises are still to come for cell biologists. In the present study, we have analyzed and compared different organelles of the endocytic and phagocytic apparatus using 2-D gel electrophoresis.

Animals↗

PubMed1997

Preparative two-dimensional gel electrophoresis of membrane proteins.

Electrophoretic techniques, and especially two-dimensional gel electrophoresis (2-DE), have provided an indispensable set of tools for the separation of complex protein mixtures as well as for the identification of protein-protein interactions. Nevertheless, after its introduction more than twenty years ago and even with recent technical developments, the separation of integral and peripheral membrane proteins, in amounts sufficient for microsequencing, is still a difficult task. Lipids present in the membrane as well as the low solubility of hydrophobic membrane proteins result in protein aggregation both on the sample application point and on isoelectric focusing. As a consequence many proteins do not enter the first or second dimension of 2-DE. Here we describe the modification of a protocol using a combination of 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate (CHAPS), chaotropic agents (thiourea, urea), Tris base and reducing agents (1,4-dithioerythritol) to improve solubilization of integral and peripheral membrane proteins. Preparative amounts of membrane proteins (up to 2 mg) were loaded during reswelling of dry immobilized pH gradients and the resulting Coomassie staining patterns were largely superimposable with silver-stained gels obtained from identical samples (4 microg). This indicates that the recovery of proteins from the sample is not significantly compromised by the scale-up procedure. A direct application of this method for the characterization and identification of membrane proteins from cellular organelles is described in another paper in this issue (I. Fialka et al., Electrophoresis 1997, 18, 2582-2590).

Animals↗

PubMed1997

Subcellular fractionation of polarized epithelial cells and identification of organelle-specific proteins by two-dimensional gel electrophoresis.

Protein targeting and sorting is accomplished by complex vesicular transport processes that are tightly regulated within a cell. This is especially important for epithelial cells because correct delivery of newly synthesized proteins as well as recycling and sorting of internalized membrane proteins is essential for the establishment and preservation of cellular polarity. Many transport events, linking various subcellular compartments, have been analyzed, but many transport mechanisms still remain unresolved. In this study we attempted to identify proteins specifically associated with distinct organelles in murine mammary epithelial cells (EpH4). We isolated subcellular compartments by continuous sucrose gradient centrifugation in order to further analyze their protein composition by high-resolution two-dimensional gel electrophoresis (2-DE). The successful separation of late endosomes (LE), early endosomes (EE) and most of the rough endoplasmic reticulum (RER) was confirmed by subsequent analysis of gradient fractions for compartment-specific enzymes and marker proteins. Both Golgi and plasma membrane (PM) were found to partially co-purify with EE in such gradients. Characteristic polypeptide patterns were revealed on 2-DE gels for fractions enriched in membranes of different origin. Based on improved sample preparation and loading techniques (this issue, C. Pasquali et al., Electrophoresis, 1997, 18, 2573-2581), we were able to identify several proteins by immunoblotting or microsequencing of Coomassie-stained spots. This will be the basis for a further characterization of organelle-specific molecules in epithelial cells as well as for the establishment of a 2-DE reference map of membrane proteins from murine mammary epithelium.

Animals↗

PubMed1997

Melanie II--a third-generation software package for analysis of two-dimensional electrophoresis images: I. Features and user interface.

Although two-dimensional electrophoresis (2-DE) computer analysis software packages have existed ever since 2-DE technology was developed, it is only now that the hardware and software technology allows large-scale studies to be performed on low-cost personal computers or workstations, and that setting up a 2-DE computer analysis system in a small laboratory is no longer considered a luxury. After a first attempt in the seventies and early eighties to develop 2-DE analysis software systems on hardware that had poor or even no graphical capabilities, followed in the late eighties by a wave of innovative software developments that were possible thanks to new graphical interface standards such as XWindows, a third generation of 2-DE analysis software packages has now come to maturity. It can be run on a variety of low-cost, general-purpose personal computers, thus making the purchase of a 2-DE analysis system easily attainable for even the smallest laboratory that is involved in proteome research. Melanie II 2-D PAGE, developed at the University Hospital of Geneva, is such a third-generation software system for 2-DE analysis. Based on unique image processing algorithms, this user-friendly object-oriented software package runs on multiple platforms, including Unix, MS-Windows 95 and NT, and Power Macintosh. It provides efficient spot detection and quantitation, state-of-the-art image comparison, statistical data analysis facilities, and is Internet-ready. Linked to proteome databases such as those available on the World Wide Web, it represents a valuable tool for the "Virtual Lab" of the post-genome area.

Algorithms↗