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Biomedical subjects

A De Barbieri

Publications and source records attributed to A De Barbieri.

At least 19 recordsLinked to original sources
PubMed1986

Use of the polytetrafluoroethylene surgical membrane for control of intra-abdominal adhesions.

The new polytetrafluoroethylene (PTFE) surgical membrane is specifically designed to prevent adhesion formation. The present study was planned in order to evaluate the effectiveness of the PTFE surgical membrane as a parietal peritoneal substitute. Furthermore, the effects of the suture material used to implant the membrane under different operating conditions (clean or contaminated surgery) were also evaluated. One hundred-eighty rats were divided into 9 groups and underwent the following surgical procedures: Group 1: removal of a parietal peritoneum patch, which was left unrepaired; Group 2: a similar peritoneal defect was covered with the PTFE membrane by 8 polypropylene sutures; Group 3 (control group): only the 8 polypropylene suture were placed on the margin of the standard peritoneal defect; Group 4: the same procedure as in Group 2, using as sewing material PTFE sutures; Group 5 (control group): only the 8 PTFE sutures were placed on the margin of the standard peritoneal defect; Group 6, 7, 8 and 9: the same procedures as in Group 2, 3, 4 and 5 respectively, adding division and subsequent reanastomosis of the caecum. Animals of each group underwent a second laparotomy 10 days or 3 months after surgery for evaluation of the extent and density of adhesions, and of the intraperitoneal organ involvement. Histological examination of adhesions which formed was then carried out. No adhesions developed in rats of group 1, while they were always present in all the other groups. Under clean surgery, the adhesions were limited to the margin of the peritoneal defect, while under contaminated surgery they formed also on its central portion. The PTFE surgical membrane itself caused variations neither of the extent and density of adhesions which developed nor of the magnitude of intraperitoneal organ involvement. The type of suture material used to implant the membrane had no effect on adhesion formation.

Abdomen↗
PubMed1984

Increased cancericidal activity of PTT.119, a new synthetic bis-(2-chloroethyl)amino-L-phenylalanine derivative with carrier amino acids. I. In vitro cytotoxicity.

A new synthetic tripeptide (p-F-Phe-m-bis-(2-chloroethyl)amino-Phe-Met ethoxy HCl), PTT.119, was demonstrated to have significant cancericidal activity against seven in vitro tumor cell lines of different origins and etiologies and against primary human AMML, ALL, and hairy cell leukemias. Viabilities of each murine tumor and rabbit, marmoset, and human leukemia and lymphoma line were significantly reduced by treatment with 1-50 micrograms PTT.119 in media containing serum. Continuous 24-h exposure or pulse treatment as short as 15 and 30 min with the tripeptide resulted in irreversible damage to the tumor cells. Under identical treatment conditions, freshly isolated human leukemic cells, particularly ALL lymphoblasts, were even more susceptible to PTT.119 than any of the tested tumor cell models. Examination of the parameters of PTT.119 activity revealed that reductions of tumor cell survival were dependent on the concentration of the tripeptide. Prolongation of PTT.119 exposure from 15 min to 24 h increased the rates of tumor cell death but did not proportionally reduce the numbers of surviving cells. Assessment of tumor cell viabilities for 5 consecutive days following pulse exposure to PTT.119 demonstrated increasing reductions in tumor cell survival, which were greatest 5 days after treatment of PTT.119 was compared with its three parental components either as individual agents or as a mixture. Both the alkylator moiety, m-sarcolysin (m.L.SL) alone or together with p-fluoro-phenylalanine and L-methionine ethoxy HCl, and L-PAM (L-phenylalanine and L-methionine ethoxy HCl, and L-PAM (L-phenylalanine mustard), the p-isomer of m.L.SL, were 1,5- to 3-fold less cytotoxic to L1210 leukemia and MJY-alpha mammary tumor cells than PTT.119. Covalent linkage of the amino acid residues to m.L.SL yielded a molecule with greatly augmented cancericidal activity capable of acting against a broad spectrum of tumor cells.

Animals↗
PubMed1983

Can heterologous collagen enhance the granulation tissue growth? An experimental study.

A purified and lyophilized sponge of native bovine tendon collagen (Gelfix) was used to plug gastric, jejunal and colonic surgical holes (phi = 6 mm) on 78 white rats. In a control group (18 rats) colonic holes were plugged with autologous epiploon. The mortality rate due to generalized peritonitis, was higher (Fischer test = 4%) in the control group than in animals treated with the heterologous collagen. The healing process was evaluated by light microscopy at sequential intervals ranging from 4 to 120 days after implantation. The heterologous collagen biological activity was evaluated as follows: 1. The sponge was labelled with Tyrosine 125I or mixed with Collagen Methyl 14C methylated. Then the radioactivity of the isolated granulation tissue cells was evaluated. The electrophoresis of these lysed cells, as well as histoautoradiography were performed. 2. Indirect immunofluorescence studies employing rabbit antibodies against fibronectin were also carried out. The heterologous collagen seemed to act as a mechanical support and as a stimulus to chemotactic migration of fibroblasts. It also appeared to participate as a nutrient substitute in the metabolic activity of the granulation tissue. Finally, heterologous collagen fibers were found to be massively bound by fibronectin.

Animals↗
PubMed1983

An experimental study on fluorocarbons as blood substitutes.

A fluorocarbon emulsion (Fluosol DA 20%) was experimented as a blood substitute. Fourty-five rats weighing 320 +/- 30 g. underwent different degrees of hemodilution, by isovolemic exanguino-transfusions. A first group (15 rats) had maximal exchange transfusion (Ht = 0,5%) with Fluosol DA 20% and was followed for 12 hours. A second group (15 rats) (control group) underwent the same procedure, but hydrolyzed gelatin 3% (Emagel) was used instead of Fluosol DA 20%. A third group (15 rats) had partial exchange-transfusion (Ht = 23 +/- 2%) with Fluosol DA 20%, and was followed for 2 months. Cerebral and cardiovascular activity, respiratory exchanges and acid-base balance as well as other basic biological parameters were evaluated in the first and second group. The initial signs of altered cerebral activity were observed with a Ht = 2%, while death occurred at Ht = 0,5% due to respiratory arrest. In the third group, a retention of fluorocarbon particles was demonstrated by gas chromatography in all the organs examined. In this group, lung and spleen lesions were also observed by light microscopy and transmission electron microscopy.

Acid-Base Equilibrium↗
PubMed1983

Synthesis, acute toxicity and chemotherapeutic anti-cancer activities of a new tripeptidic mustard.

A new antitumor agent having the chemical composition of 3-(p-fluorophenyl)-Lalanyl-3-[m-bis-(2-chloroethyl)aminophenyl]-L- alanyl-L-methionine ethyl ester hydrochloride (PTT 119) was synthetized. It fundamental toxicological data in mice and rats were assessed; its antitumor activity was investigated by establishing in mice, inoculated with L 1210 leukemia or in AKR mice with spontaneous leukemia of viral origin, a significant increase in Mean Survival Time as well as a percent increase of Increased Life Span and of the number of survivors.

Animals↗
PubMed1979

[Importance of the analysis of the carcinoembryonic antigen in clinical oncology].

330 patients (126 with gastric neoplasms, 204 with large bowel carcinoma) were submitted to serial assays to evaluate the possible relations between C.E.A. levels, pathologic stage and histologictype of the neoplasm and to define the usefulness of the C.E.A. test in monitoring the followup of the patients with gastrointestinal neoplasms. From our experience it ensues that C.E.A. test positivity (C.E.A. greater than or equal to 5 ng/ml, according to the method employed) is higher in colon neoplasms in comparison with gastric neoplasms, in the adenocarcinomas compared with the anaplastic forms. Besides, the study of the relationship with the pathologic stage points out the scanty usefulness of the C.E.A. test in the early diagnosis of gastroenteric neoplasms (Dukes A-B-C1 = 29.2%; CH stage = 88.1%). The use of C.E.A. test during the follow up seemed us of fundamental importance. We observed that: a) after radical surgery, 72% of the patients showed a normalization of C.E.A. values; b) there is a significant relationship between clinical course and C.E.A. as it can predict, sometimes several months earlier, the occurrence of relapses and metastases; c) there is also a close relationship (P less than 0.001) between the modifications of the antigen under chemotherapy and the clinical response. At present, C.E.A. seems to play, above all, fundamental role in choosing a correct treatment after radical surgery or in modifying the chemotherapeutic treatment in non surgical cases or in non radically resected patients.

Carcinoembryonic Antigen↗
PubMed1978

Cytotoxic effects of peptichemio on synchronized EUE cells.

The effect of Peptichemio (PTC) on cellular growth and on macromolecular syntheses was analyzed through the cell cycle of EUE cells. The cell response to the various treatments was measured by determining plating efficiency, growth rates and incorporation of labelled precursors of DNA, RNA and protein syntheses. Three maximum inhibition points were found on cell survival, one corresponding to the early G1, another to the middle S and a last one to the late G2. Parallel experiments of incorporation of labelled precursors of DNA, RNA and proteins revealed an effect only on DNA during the early and middle S phase.

Cell Cycle↗
PubMed1976

Effects of an antitumor multipeptide complex on immunocompetent and antigen-responsive cells.

The investigations, performed to study the possible mechanism of action of PTC, of its single constituents and of meta-levo-sarcolysin (m-L-SL) on the human immunocompetent system, are reported. The study entailed the evaluation of the effect of PTC, of its peptides and of m-L-SL on the various lymphocyte classes, employing all the more sophisticated immunological techniques such as: a) lymphocyte cultures stimulated with the various mitogens, (T and B lymphocytes); b) E rosettes (T lymphocytes); c) EA rosettes (lymphocytes with Fc receptors for IgG); d) EAC rosettes (lymphocytes with the C3 receptors); e) autoradiography and intracytoplasmic immunofluorescence (in vitro immunoglobulin neosynthesis); f) CdL (Complement-dependent Lymphocytotoxicity); g) LALI (Lymphocyte Antibody Lymphocytolytic Interaction); h) CML (antibody independent cytotoxicity i.e. Cell-Mediated Lympholysis). The evidence points out that the PTC effect on T and B lymphocytes is not comparable to that of m-L-SL which does not discriminate between the two lymphocyte populations while PTC, besides showing a scarce immunodepressive effect, preferentially affects B lymphocytes rather than T lymphocytes as shown also by the E rosette pattern. Significantly different appears also the influence of PTC, as compared with that of m-L-SL on the lymphocytes with Fc receptors for IgG (EA rosettes) and with receptors for the third component of complement (EAC rosettes) as well as on the cytotoxicity test and on the antibody dependent (LALI) and complement dependent (CdL) lytic effect. The data gleaned from this investigation allow evaluating both the effects of PTC on the immunocompetent system and the difference of its action from that of m-L-SL.

Animals↗
PubMed1976

Clinical usefulness of CEA assay.

CEA is a normal constituent of fetal cells, which can reappear in entodermally-derived neoplasms, following a de-repression process. In order to evaluate the correlation between CEA serum levels, pathological stage and histological type of tumour, and to define the usefulness of CEA in monitoring the patients with gastroenteric neoplasms, 177 patients (62 with gastric heteroplasia and 115 with large bowel carcinoma) were tested for CEA; 83 patients had pre-surgical CEA tests. It was observed that CEA positivity (serum levels greater than or equal to 5 ng/ml, employing the technique here outlined), is higher in colonic than in gastric neoplasms, and in adenocarcinomas in comparison with undifferentiated forms, moreover depending on the pathologic stage. 108 patients were tested for CEA several times and a correlation between CEA variations and clinical evolution was observed. This investigation bears out the importance to monitor the patients with gastrointestinal neoplasms with CEA test, before and after surgery, to evaluate the usefulness of surgery and, when necessary, chemotherapy and, eventually, to adopt more suitable chemotherapeutic modalities.

Carcinoembryonic Antigen↗
PubMed1976

Correlation between clinical course and CEA levels during chemotherapy.

In order to evaluate the correlation between clinical progress and CEA levels in gastroenteric tumours, particularly during chemotherapeutic treatment, CEA assay was performed on 330 patients (126 with gastric neoplasms, 204 with large bowel carcinoma). 175 out of these had a pre-operative assay. Moreover CEA test positivity (CEA larger than or equal to 5 ng/ml according to the technique employed by us) is higher in colon neoplasms compared with gastric neoplasms and in adenocarcinomas in comparison with undifferentiated forms; besides it depends on the pathologic stage. In colon tumours CEA test showed a higher positivity for left than for right forms (66.6% versus 38%). 240 patients were followed up with repeated CEA assays: the following observations were made: a - After radical surgery 72% of the patients shows normalized CEA values. b - In 198 patients who underwent radical surgery, not requiring chemotherapy, there was a close correlation between CEA levels and clinical evolution in 98% of the cases. c - 60 out of 68 patients (88%) submitted to chemotherapy for advanced neoplasms show a close correlation between CEA response to the chemotherapy and clinical response (p less than 0.001). These investigations stress, above all, the importance of CEA test to monitor the treatments performed (surgical and chemotherapeutic) and to adopt, eventually, more effective chemotherapeutic modalities.

Aged↗
PubMed1975

Significance of the presence of the various subtypes for the preparation of HBAb.

The superficial Australia antigen is essentially bound to the small particles and possesses different antigenic specificities 'a', 'd', 'g', 'w', and 'r'. The population which we tested was characterized by the major frequency (more than 90%) of the 'ag' subtype with respect to the 'ad' subtype. The doses have been achieved using the solid phase RIA, modified according to Ling, in which the specificity of the antisera anti 'a', 'd' and 'g' was obtained by means of the absorption and dissociation of the antigen-antibody complexes. The investigations which we carried out to establish the avidity of the various anti-HBs anti-sera used for research into the Au antigen, have established that in general the avidity is maximal for the anti-ad and minimal or absent for the anti-ag. From this arises the necessity for the preparation of an anti-HBs anti-serum 'pool' consisting of healthy and hepatitic donors, with an optimal relationship between the subtypes 'ad' and 'ag'. The subsequent research carried out using the true subtypes in order to establish a relationship between the subtype and the presence of the anticore antibody on RIA revealed the lack of any correlation.

Acute Disease↗
PubMed1975

Purification and characterization of the 'core' particles and their potential diagnostic use.

The basis of the postulated correlation between 'core' particles and 'Dane' particles, of their different localization in the hepatocyte and of the different relationships is the mechanism of replication of the infecting material, interesting diagnostic possibilities appear evident in the hepatitis B field. Anti-core antibodies would be alone present in the serum of the hepatitic patient, in the acute or convalescent stage, whilst in the serum of the polytransfused patient they would appear in association with the antibodies directed against the superficial antigen of the Dane particles. The 'core' particles have consequently been concentrated and purified by means of 'coat' lysis using tension actives and density gradient ultracentrifugation. With such material and a hepatitic serum purified antibody, it has been possible to prepare a radioimmunoassay with which a 'screening' may be performed to evaluate the possible diagnostic use.

Antigens, Viral↗