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Biomedical subjects

E Pozzoli

Publications and source records attributed to E Pozzoli.

At least 37 records · Page 2Linked to original sources
PubMed1985

Scanning electron microscope cytochemistry of blood cells.

The backscattered electron imaging (BEI) mode of scanning electron microscopy (SEM) has been applied to study various histo-cytochemical reactions in biological specimens since the early seventies. Due to numerous, recent technical improvements the BEI mode of SEM now belongs to the routine of many SEM laboratories. For cytochemistry, BEI has been mainly used to: visualize intracellular structures and organelles; recognize the different cell types in heterogeneous populations or tissues; study the correlations between enzymatic activities and cell surface features. We have evaluated the most relevant results obtained in the study of blood cells and the possible future applications of these techniques.

Blood Cells↗
PubMed1983

Cytochemical methods for the backscattered electron imaging mode of scanning electron microscopy: further applications to the study of human leukemic cells.

The Backscattered Electron Imaging (BEI) mode of Scanning Electron Microscopy (SEM) has been applied to the study of cells stained with various heavy metals in cytochemical reactions. Improvements or modifications of some of these methods and their application to the study of normal and leukemic leukocytes have been evaluated in this report. The results obtained after staining peroxidase-positive granules with osmium, copper, cobalt-nickel and gold-cobalt are compared. Granules containing non-specific esterase activity were demonstrated in the BEI mode after incubation of the cells in Hanker medium and staining with osmium. While sites of acid phosphatase activity were easily localized with a conventional lead method, alkaline phosphatase activity was demonstrated only in the phagocytic vacuoles of cells previously incubated with latex particles and subsequently stained with lead. Cell nuclei were identified in the BEI mode after silver methenamine or bismuth staining. Combining their cell surface and cytochemical characteristics a more accurate identification of the different blood cell types with the SEM becomes possible.

Acid Phosphatase↗
PubMed1983

Alkaline phosphatase activity in phagocytizing granulocytes: a backscattered electron imaging study.

The scanning electron microscope (SEM) in the backscattered electron imaging (BEI) mode has been used to detect alkaline phosphatase activity in normal human PMNs using a lead method. Unfortunately commercial scanning electron microscopes do not allow resolution of the small and dispersed lead depositions in the secondary granules. However, polymorphonuclear leukocytes (PMNs) previously incubated with latex particles, show well evident lead precipitates allowing identification of different phases of the phagocytic sequence. In fact the finding of irregular depositions arranged around a central not-emitting zone might be due to the secondary granules gathering near the phagocytic vacuole. Moreover, homogeneous, round, well defined precipitates, having a diameter slightly larger than latex particles, probably corresponding to vacuoles filled with the enzyme after granules coaslescence and fusion.

Alkaline Phosphatase↗
PubMed1979

Ultrastructural study of leukemic cell phagocytosis using the myeloperoxidase reaction.

The phagocytosis (in the absence of serum factors) of zymosan particles by peripheral leukocytes isolated from ten patients with acute leukemia (AMbL, AMoL, AMML, AUL, ALL and CML-BC) was studied at the electron microscope. An evident phagocytic activity was observed only in the cells in which cytochemical and ultrastructural features suggested that the blast elements belonged to the monocytic series. However, no phagocytosis by unclassifiable leukemic blasts was observed, even though they had some submicroscopic characteristics of the monocytic series. These findings suggest that phagocytic capacity develops during the course of cell differentiation, becoming striking only when the blast cell acquires the ultrastructural features of the pro-monocytic stage. Using the myeloperoxidase reaction, this study also demonstrates a morphological alteration in the degranulation process after the ingestion of zymosan particles in both the blasts and the mature PMN cells of leukemic patients. This defect could be related to the susceptibility to severe infections usually found in subjects with hematological malignancies.

Humans↗
PubMed1976

Acute lymphoblastic leukemia: a study of 25 cases by scanning electron microscopy.

Cells from 25 cases of acute lymphoblastic leukemia (ALL) were studied under the scanning electron microscope (SEM). In 24 of the cases, the vast majority of circulating leukaemic cells had few microvilli. Villous cells were rarely encountered and prominent ridge-like profiles and ruffled membranes were not seen. Only six cases were studied by immunological techniques and four of the cases were of the null type while in two the cells bore detectable T-markers. It seems that ALL is almost always associated with the presence of cells with few microvilli in the peripheral circulation, differing in this respect from most cases of CLL. Although circulating leukaemic lymphocytes with few microvilli are sometimes seen in CLL, the most frequent cell type encountered is a more villous lymphocyte. Differences between leukaemic cells from patients with ALL, CLL and non-lymphoblastic leukaemias are discussed. It appears that SEM may help to distinguish lymphoblastic and nonlymphoblastic leukaemic cells in many instances and can be used as a useful adjunct to other modes of microscopy in the diagnosis of acute leukaemia.

Adult↗
PubMed1976

Autoantibodies and spleen cell-mediated cytotoxicity in adriamycin-induced myocardiopathy in rabbits.

Spleen cells from rabbits affected by adriamycin-induced cardiomyopathy were specifically cytotoxic for rabbit embryonic heart cells in microcytotoxicity tests. The interactions between "sensitized" spleen cells and rabbit embryonic heart cells were observed by scanning electron microscopy. Sera from these rabbits were shown by immunofluoresence to contain antibodies reactive with rabbit embryonic heart, kidney, and muscle cells. Cytotoxic antibodies were not detected. These sera contained factors that enhanced the cytotoxicity mediated by "sensitized" spleen cells and made normal spleen cells capable of destroying targets. The detection of these factors and of cytotoxins was dependent on the method of target-effector cells treatment by serum.

Animals↗
PubMed1975

Human platelet aggregation by mixed cryoglobulins.

Glomerulonephritis in idiopatic mixed cryoglobulinemia represents perhaps a glomerular damage by immune complexes. In this study, a sigmoidal-like curve was obtained after addition of 13 different mixed cryoglobulins to both autologous and isologous platelet-rich plasma, tested in platelet aggregometer. The lag phase of the curve corresponds to platelet phagocytosis of cryoglobulin-binding ferritin, as shown in electron microscopy and the optical density decrease phase corresponds to the aggregation of platelets that shows the same ultrastructural characteristics of ADP-induced platelet aggregation. This platelet aggregation is inhibited by different drugs. Intraglomerular platelet aggregation by cryoglobulins might play a key role in determining the glomerular damage in cryoglobulinemia by the release of nucleotides and vasoactive amines.

Blood Platelets↗
PubMed1975

Platelet aggregometry and anti-platelet isoantibodies.

102 sera from polytransfused patients have been screened in platelet aggregometry. Anti-human platelet isoantibodies, tested against 'responsive' human platelets in PRP, give in the aggregometer a decrease in optical density recorded as a sigmoidal curve. In the first step of reaction PF3 availability suggests that the primary action of antibody is to damage the platelet membrane. The second step might be a true aggregation (an ADP-mediated platelet clumping) or a platelet lysis, depending on the type and the potency of antibody, on the type of platelets (normal or thrombasthenic) and on some experimental conditions. These conclusions, confirmed by electron microscopy findings, suggest that aggregometry is a very rapid and simple method of detecting platelet antibodies.

Adenosine↗
PubMedDate not supplied

Value of intraoperative resistive index in kidney transplant.

The value of the resistive index (RI) obtained by echo color doppler evaluation of the transplanted kidney is still not well established. Many authors consider the RI to be nonspecific sign of rejection, acute tubular necrosis, or urinary tract obstruction, but its specificity remains low. In this paper, we report our experience with RI determinations in 34 consecutive kidney transplants at different times namely: perioperatively, at 24 hours, at 3 days, at 6 and at 9 days posttransplant. In all patients intraoperative RI was normal. RI increased significantly after transplantation in 10 patients who eventually developed a complication: delayed function, acute rejection, and spontaneous kidney ruptures. This increment from the baseline value was already significant at 24 hours after the kidney transplant, indicating a possible posttransplant complication (0.62 +/- 0.07 vs 0.76 +/- 0.04; P = .0004). We conclude that the value of RI in the early posttransplant phase should be considered an important aid for the early diagnosis of posttransplant complications.

Adolescent↗