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Biomedical subjects

L Marchetti

Publications and source records attributed to L Marchetti.

At least 55 records · Page 3Linked to original sources
PubMed1996

Glycocytochemistry of the mouse parotid gland. Investigation by lectin-gold techniques on Bioacryl and Lowicryl K4M embedded specimens.

In this study colloidal gold methodologies that allow the lectin affinity patterns in the mouse parotid gland to be studied by postembedding techniques were addressed. DBA, Con A, PNA, WGA and LTA lectins conjugated with gold particles or horseradish peroxidase for a direct or indirect technique of binding were used. Thin sections were obtained from tissue embedded in the acrylic hydrophilic resins Bioacryl and Lowicryl K4M. The most satisfactory results originated from sections infiltrated in Bioacryl and submitted to the indirect technique of binding. The mouse parotid gland appeared to be composed of polymorphous secretory granules differentially stained by lectins. The glycosylated components of acinar cells reacted intensely, and gold particles specified the ultrastructural distribution of lectin affinity sites reflecting the location of beta-galactose, alpha-N-acetylgalactosamine, beta-N-acetylglucosamine, alpha-D-mannose, and alpha-L-fucose in the electron-dense or electron-lucent areas of bizonal, mottled, and target granules.

Acrylic Resins↗
PubMed1995

Influence of organic and inorganic growth supplements on the aerobic biodegradation of chlorobenzoic acids.

The effect of yeast extract and its less complex substituents on the rate of aerobic dechlorination of 2-chlorobenzoic acid (2-ClBZOH) and 2,5-dichlorobenzoic acid (2,5-Cl2BZOH) by Pseudomonas sp. CPE2 strain, and of 3-chlorobenzoic acid (3-ClBZOH), 4-chlorobenzoic acid (4-ClBZOH) and 3,4-dichlorobenzoic acid (3,4-Cl2BZOH) by Alcaligenes sp. CPE3 strain were investigated. Yeast extract at 50 mg/l increased the average dechlorination rate of 200 mg/l of 4-ClBZOH, 2,5-Cl2BZOH, 3,4-Cl2BZOH, 3-ClBZOH and 2-ClBZOH by about 75%, 70%, 55%, 7%, and 1%, respectively. However, in the presence of yeast extract the specific dechlorination activity of CPE2 and CPE3 cells (per unit biomass) was always lower than without yeast extract, although it increased significantly during the exponential growth phase. When a mixed vitamin solution or a mixed trace element solution was used instead of yeast extract the rate of 4-ClBZOH dechlorination increased by 30%-35%, whereas the rate of 2,5-Cl2BZOH and 3,4-Cl2BZOH dechlorination increased by only 2%-10%. The presence of vitamins or trace elements also resulted in a specific dechlorination activity that was generally higher than that observed for the same cells grown solely on chlorobenzoic acid. The results of this work indicate that yeast extract, a complex mixture of readily oxidizable carbon sources, vitamins, and trace elements, enhances the growth and the dechlorination activity of CPE2 and CPE3 cells, thus resulting in an overall increase in the rate of chlorobenzoic acid utilization and dechlorination.

Aerobiosis↗
PubMed1995

Carbohydrate-deficient transferrin in alcohol and nonalcohol abusers with liver disease.

Carbohydrate-deficient transferrin (CDT) has been demonstrated to be a marker of prolonged heavy alcohol consumption. We compared this marker with gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV) in alcohol and nonalcohol abusers with liver disease. Our results confirm that the sensitivity of CDT in alcoholics is high, although lower than that of GGT and MCV; however, the specificity of CDT was higher than that of the other two markers. This finding supports the notion that CDT is only partially influenced by the presence of liver damage, whereas increases of GGT and MCV are greatly affected by several factors, including liver damage and drugs. Moreover, we observed that the sensitivity and the specificity of CDT were greater than those of GGT and MCV in younger drinkers.

Adult↗
PubMed1995

Activated and memory alveolar T-lymphocytes in idiopathic eosinophilic pneumonia.

To investigate the possible involvement of T-lymphocytes in the immunopathogenesis of idiopathic eosinophilic pneumonia (IEP), we have evaluated the phenotypic characteristics both of peripheral blood and alveolar lymphocytes in six patients with symptomatic IEP, and in 24 healthy nonsmokers as controls, by employing bronchoalveolar lavage (BAL), monoclonal antibodies, and flow-cytometry. In IEP, total and differential cell counts showed a mild alveolitis with an increase of eosinophil percentage and number; the alveolar lymphocyte count was also increased. In BAL, the total number both of CD4+ and CD8+ lymphocytes was significantly raised; CD4+ cells expressed early (CD25) activation antigens. The analysis of CD45R0, CD45RA and CD62L coexpression in IEP patients, when compared to healthy controls, revealed an accumulation of alveolar CD4+ cells showing phenotypic repertoire usually expressed by memory T-cells (CD45R0+, CD45RA-, CD62L-). CD8+ alveolar lymphocytes did not show any significant increase of activation antigen coexpression. Circulating lymphocytes were not significantly increased and showed only a significantly higher CD25 expression. These data suggest that a pivotal role is played by activated and memory CD4+ alveolar lymphocytes in IEP patients.

Adult↗
PubMed1994

An attempt to control the polychlorocatechol pigment production during 3-chlorobenzoate aerobic co-metabolism in growing-cell batch culture.

A strain of Pseudomonas fluorescens, designed CP30, was capable of co-metabolizing 3-chlorobenzoic acid via chlorocatechols, thus producing a polychlorocatechol black pigment. The pigment production was found to be enzyme-mediated in P. fluorescens cultures; however, the results of the autoxidation studies suggested that a large amount of pigment could derive from the simple autoxidation of the chlorocatechols accumulated in the CP30 culture during the 3-chlorobenzoate degradation. The polymerization of chlorocatechols should reduce the toxicity of the culture and generally resulted in a large production of a water-insoluble (i.e. a easily removable) pigment with the release a large amount of chloride ions. Both 3-chlorobenzoate degradation and pigment production were stimulated and inhibited in the same way by high and low pH values, respectively, in CP30 cultures; the culture conditions which permitted an extensive 3-chlorobenzoate degradation with the lowest pigment production were not identified. However, on the basis of the detoxification property of the pigment production process, high pH and dissolved oxygen concentrations appears to be the most suitable culture conditions for an enhanced detoxicant treatment of 3-clorobenzoate-contaminated waste water.

Aerobiosis↗
PubMed1994

[Evaluation of cardiac risk in patients undergoing major vascular surgery. Usefulness and limitations of transesophageal atrial pacing].

Patients undergoing vascular surgery are at high risk of developing cardiac events in the perioperative period. The aim of the study was the evaluation of the predictive accuracy of transesophageal atrial pacing (TAP) in identifying patients at higher risk of developing major cardiac events (cardiac death, acute myocardial infarction, unstable angina, heart failure and sustained ventricular tachyarrhythmias). We studied 96 consecutive patients, 80 males and 16 females, median age 63, requiring arterial surgery (aortofemoral or aortoiliac bypass and thromboendoarterectomy, abdominal aneurysm resection and extracranial carotid thromboendoaterectomy). TAP was performed without cardioactive drugs in all patients, but one. After surgery CK and CKMB serial assessment and ECG recording were performed daily until the seventh postoperative day. Preoperatively all patients were admitted to the Intensive Care Unit and submitted to haemodynamic monitoring with Swan-Ganz catheter at least for 72 hours. Three patients did not undergo surgery because of severe ST depression during TAP. Thus, 93 patients (96.8% of the series) were the subject of this report. In the postoperative period only two events (2.1% of the patients) were recorded, one relapsing acute myocardial infarction and one ventricular fibrillation, both in patients with negative TAP. No death occurred. Our study shows a very low prevalence of major cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Biosynthesis and cytoplasmic accumulation of a chlorinated catechol pigment during 3-chlorobenzoate aerobic co-metabolism in Pseudomonas fluorescens.

A strain of Pseudomonas fluorescens was capable of co-metabolizing 3-chlorobenzoic acid with the production of a chlorinated catechol black pigment. A peroxidase and another enzymatic activity referred to as a polyphenol oxidase were found to be involved in the oxidation of 4-chlorocatechol to 4-chloro-1,2-benzoquinone, i.e. in the production of highly reactive substrates for pigment formation. Therefore, P. fluorescens cells were seen to take an active part not only in 3-chlorobenzoate mineralization but also in overall pigment production. pH was found to be a key parameter in the regulation of the activity of P. fluorescens oxidoreductive enzymes. Ultrastructural investigations showed that electron dense granules of pigment were distributed throughout the cytoplasm of Pseudomonas fluorescens cells grown in presence of 3-chlorobenzoate, as confirmed also by Thiéry cytochemical investigations. In these cells, an extensive contraction of the cytoplasm as well as a significant damage to the cell wall after two days of incubation, suggested that pigment production caused a premature death of the cells accompanied by the leakage of the cell content. Pigment production seemed to occur mostly in the cytoplasmic context where the electron dense material accumulates until it is released in the medium after the cell lysis.

Aerobiosis↗
PubMed1993

Myocardial function in early hours after coronary artery bypass grafting: comparison of two cardioplegic methods.

The theoretical advantages of retrograde blood cardioplegia combined with anterograde blood cardioplegia and warm reperfusion before aortic unclamping during coronary surgery were evaluated in 41 patients (group 2). The early postoperative myocardial function of this group was compared with that of 55 patients (group 1) in whom cold crystalloid cardioplegia was administered. The following variables were measured and analyzed by multivariate statistical analysis: heart rate, left atrial pressure, systemic arterial pressure, cardiac index, left ventricular stroke work index, ventricular function, oxygen delivery, hemoglobin, partial oxygen pressure in mixed venous blood, arteriovenous oxygen difference, carbon dioxide production per square meter, and cardiac isoenzyme of creatine-kinase. The myocardial function improved progressively and cardiac enzymatic release was low for both groups 9 hours after admission to the intensive care unit. However, group 2 had significantly higher oxygen delivery, carbon dioxide production per square meter, cardiac index, left ventricular stroke work index, and ventricular function and significantly lower left atrial pressure and mean systemic arterial pressure than that of group 1. The best separation of group 2 from group 1 occurred at the ninth hour, with a probability of correct recognition of 92.1%.

Blood Pressure↗
PubMed1993

Adenosine deaminase activity and fibronectin levels in bronchoalveolar lavage fluid in sarcoidosis and tuberculosis.

We have studied Adenosine Deaminase (ADA) activity and Fibronectin (FN) levels in Bronchoalveolar Lavage Fluid (BALF) from 50 patients with Sarcoidosis (15 active, 35 non active) and from 24 patients with Pulmonary Tuberculosis in order to evaluate relationships between both ADA and FN in BALF and alveolitis data. BALF ADA activity increases in active sarcoidosis as well as in tuberculosis, as a result of activation, differentiation and proliferation of blood-derived mononuclear alveolar cells. In sarcoidosis this hypothesis is supported by the significant positive correlation observed between ADA activity and both the number of alveolar CD4+ lymphocytes and the number of alveolar lymphocytes bearing activation antigens (CD25 and VLA-1). BALF FN levels increase, showing highest values in active sarcoidosis. ADA and FN elevation in BALF from active sarcoidosis patients could be suggested as additional markers of disease activity. Highest BALF ADA/Albumin ratio observed in pulmonary tuberculosis patients suggests an increased local production and differentiates pulmonary tuberculosis from active sarcoidosis. Increased FN/Albumin ratio observed in non active sarcoidosis appears to be related to a similar mechanism during the reparative process following granulomatous inflammation.

Adenosine Deaminase↗
PubMed1993

Thermal behaviour of the rabbit sublingual gland.

The purpose of this study was to show how some aspects of the biological matrix water can be investigated by thermoanalytical methods when using thermogravimetry and differential scanning calorimetry. Such methods allow to investigate the water in the rabbit sublingual gland and to quantitate it. The results supported the view that the water contained in this secretory organ show a large number of energetic interactions established on the basis of differential steps of water release by thermal disruption.

Animals↗
PubMed1992

The hare parotid gland: ultrastructure and histochemistry of acinar and ductal cells.

The parotid gland of the hare Lepus europaeus was studied by electron microscopy. The parenchyma consists of secretory areas (acini) and ductal segments (intercalated, striated and excretory ducts). Acinar cells showed a marked heterogeneity due to the presence of secretory granules characterized by different size, electron-density and degree of membrane merging in addition to the occurrence of flattened and dilated rough endoplasmic reticulum. Acinar cells had variable affinity for PAS and PA-TCH-SP staining but were HID- and LIT-TCH-SP negative. Intercalated duct cells lacked secretory granules. Striated ducts were lined by four cell types namely light cells, dark cells, vacuolated cells, and typical striated cells. Excretory ducts showed some scalloping on the apical region of the light cells.

Animals↗
PubMed1992

On the fine structure and complex carbohydrate cytochemistry of the rabbit parotid gland.

The parotid gland of the rabbit, a lagomorph species, was studied by ultrastructural techniques and carbohydrate ultracytochemical stainings. The rabbit parotid gland is a peculiar mixed gland consisting of serous and mucous secretory cells due to their histochemical properties supported by biochemical findings. Acinar cells exhibit heterogeneous features of secretory granules with different electrondensity and occasional presence of subunits. Intercalated duct cells show nuclei with deep indentation and apical granules partly similar to acinar secretory products. Striated ducts are characterized by three different cell populations, namely "light cells" with small secretory granules, "dark cells" rich of scattered mitochondria and typical striated cells. The presence of differentiated cell types within striated duct segments lends credence to the idea that, in addition to the role in electrolyte transport, some ductal cells may be involved in secretion and/or absorption of glycosylated products.

Animals↗
PubMed1991

Degradation and mineralization of 3-chlorobiphenyl by a mixed aerobic bacterial culture.

A mixed bacterial culture obtained from polychlorinated-biphenyl-contaminated river sediments proved capable of degrading 3-chlorobiphenyl (3-CB) under aerobic laboratory conditions. Almost total mineralization of 150 mg/l of 3-CB occurred when, after 3 days of incubation, the mineral medium was supplied with benzoic acid as a carbon source. Two strains of Pseudomonas capable of degrading the substrate to 3-chlorobenzoic acid and a strain of Pseudomonas fluorescens capable of co-metabolizing this metabolite were selected from the mixed culture. A nearly stoichiometric amount of chloride, which defines the percentage of total mineralization, was eliminated during mixed culture growth.

Bacteria, Aerobic↗
PubMed1991

Polymorphism of the human gamma chain fibrinogen gene.

Nucleotide sequence comparisons of the published cDNAs and genomic sequences coding for the gamma-chain of human fibrinogen revealed several differences. We isolated two independent human cDNA clones, coding for part of this protein and compared their sequences, which are identical with the published relevant data. Our sequence allowed us to solve a conflict for aminoacid 88. All the remaining differences resulting from this comparison occurred in the third position of a codon and did not change codon properties or restriction sites. The level of polymorphism of this gene is discussed, taking into account also the nucleotide differences among all the published relevant data.

Base Sequence↗