Biomedical subjects

D Piccolo

Publications and source records attributed to D Piccolo.

42 records · Page 3Linked to original sources

PubMed1979

The influence of some metabolic inhibitors on phagocytic activity of mouse macrophages in vitro.

The action of different metabolic inhibitors on phagocytosis by macrophages from mouse peritoneal exudate cultured in vitro was studied. The following metabolic inhibitors were tested: sodium iodoacetate, sodium fluoride, sodium fluoroacetate, sodium malonate, 2-4-dinitrophenol, sodium azide, ouabain and cycloheximide, all at the concentration of 10(-3) M. Iodoacetate caused a strong inhibitory effect on phagocytosis; this observation confirms that glycolysis is the main source of energy for the phagocytic process. On the contrary, fluoride, although it is an effective inhibitor of glycolysis, did not exert any effect. This difference may be explained by the fact that sodium fluoride blocks anaerobic glycolysis only in vitro at an unphysiological temperature (0 degrees C). Fluoroacetate and malonate, two compounds which interfere with the Krebs cycle, did not inhibit phagocytosis, but it is known that the Krebs cycle activity is poorly developed in the macrophagic cells. Sodium azide and 2-4-dinitrophenol, two inhibitors of oxidative phosphorylation, showed an effect on phagocytosis only after 3 h of contact with the cell cultures. Ouabain blocks Na+ and K+ transport across the plasma membrane and, probably, it inhibited phagocytosis by interfering with the movements of the cell membrane. Finally, the mode of action of cycloheximide on phagocytosis is uncertain. This compound inhibits the protein synthesis and, perhaps, it can act by preventing the renewal of the cell membrane.

Animals↗

PubMed1977

The influence of some metabolic inhibitors on in vitro phagocytizing macrophages. I. The behaviour of human macrophages.

In the present work the uptake of foreign materials by macrophages has been studied in order to elucidate its possible energy-dependent mechanisms. We used monolayer cultures of macrophages from human peripheral venous blood, treated with the following metabolic inhibitors: iodoacetic acid, fluoroacetic acid, sodium fluoride, sodium malonate, sodium azide, 2-4-dinitrophenol, cycloheximide, and ouabain. The test assay was performed by using a zymosan particles suspension in Mc Coy 5 A medium supplemented as follows. The quantitation of phagocytosis was obtained by direct count of intracellular zymosan particles by oil 100X microscopy and the results were submitted to a statistical evaluation. The most effective inhibitor we found was iodoacetate, an inhibitor of anaerobic glycolysis, but fluoride, which acts on the same metabolic pathway at a different site, was quite ineffective. The same ineffectiveness we found for fluoracetate and malonate which act on the Krebs cycle. On the contrary, dinitrophenol (uncoupler of oxidative phosphorylation), azide (inhibitor of cytochrome linked-phosphorylation), ouabain (inhibitor of membrane ATPase activity) and cycloheximide (inhibitor of protein synthesis) give a remarkable decrease of index of phagocytosis after a 3h incubation. In conclusion, we can suppose that the energy-dependent phagocytosis is first depending on transport across the cell membrane (ATPase activity and protein synthesis) and second both on anaerobic glycolysis and oxidative phosphorylation.

Antimetabolites↗

PubMedDate not supplied

The idiopathic dilated cardiomyopathy in man. A biochemical and molecular study on myosin.

We studied subunit composition and Ca(++)-activated ATPase activity of myosin isolated from atria and ventricles of hearts explanted from patients suffering from idiopathic dilated cardiomyopathy. At variance with previously published data, we have been unable to detect in the ventricular subendocardial layers a significant amount of myosin atrial-like light chain 1 (ALC1), which has been reported to be related to some hemodynamic features of the hypertrophied and failing heart. Such a subunit was not visible in the septum and in the subepicardial layers either. On the contrary, in both atria a ventricular-like light chain 2 (VLC2) was found. The nature of this additional light chain was confirmed on the basis of two-dimensional electrophoresis and immunoblotting techniques with polyclonal antibodies reacting with VLC2. In these patients we also observed a depressed Ca(++)-activated ATPase activity, both in atrial and ventricular myosin. The explanation for this finding in ventricles still remains obscure since neither myosin light chains, nor myosin heavy chains showed any difference between patients with dilated cardiomyopathy and controls. On the contrary, in atria we clearly identified changes consistent with the expression of myosin heavy chains of ventricular type and VLC2, which can account for the depressed Ca(++)-activated ATPase activity.

Calcium-Transporting ATPases↗

PubMedDate not supplied

Histopathologic interobserver agreement on the diagnosis of melanocytic skin lesions with equivocal dermoscopic features: a pilot study.

AIMS AND BACKGROUND: Dermoscopy (dermatoscopy, skin surface microscopy, epiluminescence microscopy) has been increasingly employed in recent years for the preoperative detection of cutaneous melanoma, and dermatoscopic features of pigmented skin lesions have been previously defined using histopathology (HP) as the "key to the code". The aim of the present study was to evaluate the interobserver agreement on the HP diagnosis in a series of epiluminescence microscopy equivocal melanocytic skin lesions. STUDY DESIGN: Ten melanocytic skin lesions were selected on the basis of diagnostic disagreement of at least 2 out of 9 epiluminescence microscopy observers. The histologic specimens from the 10 lesions were examined by 9 HP observers. The agreement of the HP diagnoses was calculated by means of Fleiss' k statistics. RESULTS: The overall HP agreement was less than excellent (k = 0.5). When considering the prevailing epiluminescence microscopic and HP diagnoses, 2 cases were shown to be epiluminescence microscopy false-negative melanomas. Virtually no agreement was found among epiluminescence microscopy observers in 4 cases (40%) or among HP observers in 3 cases (30%). However, only one pigmented skin lesion remained unclassifiable on epiluminescence microscopy as well as HP. CONCLUSIONS: When at least 2 epiluminescence microscopy experts disagree in the evaluation of a given melanocytic skin lesion, even HP consultations may give equivocal results. The need to establish more reliable epiluminescence microscopic and HP criteria by performing an improved and meticulous clinicopathologic correlation, e.g. by using telecommunication via Internet, is emphasized.

Adult↗

PubMedDate not supplied

[Are small-size depressed-type colorectal neoplasias really the expression of a early stage of colorectal cancer. Apropos of a clinical case].

A route of colorectal cancer development other than the adenoma-carcinoma sequence has recently become an issue due to the discovery of the depressed-type early colorectal cancers. Despite the protruding shapes of depressed-type early colorectal cancers, they probably have biological characteristics which differ from those of the usual polyp lesions. They show more aggressive behavior than the polypoid type and can arise de novo. Depressed-type lesions, in contrast to flat-type or protruded-type lesions, tend to invade the submucosa rapidly, so it is better treat them surgically from the outset. We report a case of a small depressed-type colorectal cancer involving the caecum of a 79-year-old male patient.

Adenocarcinoma↗

PubMedDate not supplied

Phagocytosis and cellular metabolism (a study on mouse and human macrophages in culture).

The uptake of foreign particles by mouse and human macrophages influenced by various metabolic inhibitors was examined in order to obtain further informations about the energy-dependent mechanisms which are involved in the phagocytic process. The inhibitors employed were iodoacetate, fluoroacetate, fluoride, malonate, sodium azide, 2-4-dinitrophenol, cycloheximide and ouabain. These substances were tested on monolayer cultures and the phagocytosis assay was performed by using zymosan suspension in the nutrient media. The quantitation of phagocytosis was obtained by the direct count of intracellular zymosan particles (immersion microscopy, 100x) and the results were evaluated and compared by biometrical analysis. The effects of these inhibitors on phagocytosis and their relation with the metabolic intracellular pathways are discussed.

Animals↗