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Biomedical subjects

G C Tassi

Publications and source records attributed to G C Tassi.

At least 37 records · Page 2Linked to original sources
PubMed1979

[Use of staphylococcal protein A for the detection of rubella virus IgM antibodies].

The ability of Staphylococcus aureus protein A to bind human serum immunoglobulin of different classes and the conditions which allow a selective reduction of IgG in comparison to other immunoglobulin classes were preliminarly studied. Working under standardized conditions, a recovery of 3.5% of the initial value for IgG, of 40-50% for IgM and of 70-75% for IgA was obtained. Rubella HI antibodies, before and after staphylococcus treatment, were titred in 88 sera collected from adult women at different times from hexantema and in 210 sera of 109 subjects exposed to eventual contamination. The results were compared with the ones obtained by means of sucrose density gradient centrifugation followed by titration of rubella HI antibodies in the fractions. The tests proved that HI antibodies titration, before and after serum treatment with staphylococcal protein A, can be used, as presumptive test, for the research of rubella specific IgM antibodies. In fact, all the sera, on which the presence of rubella IgM antibodies was proved by sucrose density gradient centrifugation, were also positive after staphylococcus treatment. In 15% of sera resulting positive for HI rubella antibodies after staphylococcus treatment, usually at low titer, the presence of specific IgM antibodies was not detected by serum fractionation on sucrose density gradient ("false positive" cases). The results of serological diagnosis, carried out by using treatment with staphylococcal protein A and serum fractionation on sucrose density gradient, matched the clinical-epidemiological data. Twenty-seven women, out of 28 examined during the first three months of pregnancy and for whom serological diagnosis of a "recent" rubella virus infection was negative, had normal children at normal time. Therefore only in one case a spontaneous abortion occurred for uncertain causes. Rubella virus was isolated from the embryo of a woman who interrupted pregnancy because asymptomatic rubella virus infection was serologically diagnosed in the second month.

Antibodies, Viral↗
PubMed1979

[Use of a new radioenzymatic test in urticaria and drug allergy].

The Authors report preliminary data obtained with the histamine release test, evaluated with a radioenzymatic technique, in patients with a symptomatology highly indicative for penicillin allergy (21 cases) and in patients with urticarial forms (20 cases) or atopic dermatitis (5 cases). This technique, suitably modified, turned out very sensitive and able to detect histamine concentrations in the picogram range. The use of this test in type I immunoreactions, after Ig removal and fixation (IgE, IgG4) from basophils of atopic and normal subjects, pointed out its remarkable advantages (sensitivity, specificity, reliability) in comparison with other techniques. The results of our case-list, even if preliminary seem to be indicative for an extension of the trial to a wider number of patients both with allergies of pharmacological type and with urticarial forms or atopic dermatitis.

Basophils↗
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

[Atopy and RAST. Diagnostic, therapeutic and standardization problems. Experimental contribution (allergy to antibiotics)].

The authors outline the immunological and immunogenetic bases of atopy, as well as the radioimmunological techniques employed in the allergological diagnosis and purification as well as standardization of the allergens. The latest trends of the allergological immunotherapy are examined, covering fundamentally two wide fields: the possibility to elicit an aspecific immunological tolerance (soluble suppressor substances of IgE response; Asp-Ser-Asp-Pro-arg pentapeptide, D-GL copolimer conjugated aptens) or the specific induction of "suppressor" mechanisms (allergoids, modified allergens). The preliminary results obtained on sera of patients with a symptomatology highly indicative of penicillin allergy, employing RAST Penicilloil G and Penicilloil V, are also reported.

Allergens↗
PubMed1978

[Syphilis serology: "ELISA", a third generation test].

The characteristics and the working modalities of ELISA (Enzyme Linked Immunosorbent Assay) are outlined at the onset. Subsequently, the Authors refer the data relevant to the use of ELISA in the syphilis serodiagnosis, by describing the operative phases for the working out of the test with the enzyme peroxidase, and reporting the results of the clinical investigation performed on primary and secondary syphilis in progress, on treated primary and secondary syphilis (examinations performed 1 to 10 years after the end of therapy), on healthy blood donors, and on samples of false biological positivities. On the basis of the analysis of the results, the Authors feel that ELISA for its characteristics of sensitivity, easiness in carrying out, rapidity and reproducibility, might find a rational indication in the modern serodiagnosis of the syphilis.

Blood Donors↗
PubMed1978

[Use of an immunomodulator (levamisole) in HbsAg positive patients].

The results of some clinical trials performed with levamisole on 12 HBsAg-positive subjects, including 5 patients with aggressive chronic hepatitis, (ACH) 2 patients with persistent chronic hepatitis (PCH) and 5 healthy carriers are reported. Levamisole was administered in 2.5 mg/Kg/day doses for three consecutive days. During treatment prothrombin activity normalized in ACH and PCH as well as transaminases, the latter starting from the 4th week, even though a two-fourfold increase of the starting values was observed in the first weeks of disease. HBsAg, anti-HBs titres and immunocomplexes values did not show any significant variations, but for 1 case, while some immunological parameters (E, EA rosettes) normalized in those cases showing base- values lower than the norm.

Adult↗
PubMed1978

[Immunodeficiencies and enzyme deficiencies].

The first part of the paper outlines the actual situation of the recent investigations on the interpretative problem of the immunological deficits combined with enzymatic deficits. ADA deficit associated with combined immunodeficiency is an autosomal recessive form. Low enzyme levels, which is produced by a structural gene located on chromosome 20, were detected in chronic lymphatic leukemias where ADA decrease is correlated to low levels of T lymphocytes and the prevalence of an atypical B lymphocyte population. Particularly high levels of ADA were detected in acute lymphoblastic leukemias, in transplant rejection, in blastic crisis of chronic myeloid leukemia... NP deficit is associated with a T branch immunodeficiency, with high levels of inosine, guanosine, hypouricemia, hypochromic microcythemia and hematopoietic tissue megaloblastosis. This enzyme, with trimeric structure, whose structural gene is located on chromosome 14, shows a cytoplasmic location, and its maximum activity is to be found in T lymphocytes separated by rosetting. IGPT deficit is to be held responsible for the neurological Lesch-Nyhan syndrome. This deficit is associated with a depression of B lymphocyte function evaluated as response to the mitogens (PWM, Protein A) or as specific immunoglobulins production. At last the Authors report some personal investigations performed on hemolysates and lymphocytes of subjects with impaired immunity, as well as on some children at birth to establish the correlation between ADA and NP behaviour and immunosurveillance. Lastly, the data on the variations of the enzymatic and immunological parameters of subjects with immunodeficiency associated to enzymopenia after red cell transfusion are reported.

Adenosine Deaminase↗
PubMed1977

Localization of carcinoembryogenic antigen (CEA) in normal, inflammatory and neoplastic colonic mucosa by immunofluorescence.

To evaluate the role of tissutal carcinoembryonic antigen (CEA) in different types of colonic mucosae specimens from normal, inflammatory and neoplastic tissues were examined in immunofluorescence (IFL) with a monospecific CEA antiserum. Neither the pattern of IFL nor the amount of antigen in the tissue (defined as the antiserum dilution beyond which CEA staining was no longer visible), could reliably distinguish any histological entity a consistent overlap being observed between positive and negative results in malignant and non malignant mucosa. No correlation was found betwen IFL and the level of serum CEA. It is concluded that the tissutal localization of CEA by immunohistochemistry plays no role in the differential diagnosis of different types of colonic mucosa.

Carcinoembryonic Antigen↗
PubMed1976

[The sexual transmission of Australia antigen (HBsAg)].

Examination was made of 300 serum specimens taken from patients with latent syphilis, in order to study the incidence of HBsAg antigen as compared with the normal population. Examination was by means of counter immunoelectrophoresis, radioimmunoassay and electron microscope with negative staining. The incidence as shown by counter immunoelectrophoresis is 2.33%, by RIA 10% with 86.6% of sub-type AY and 13.3% of sub-type AD, which is significantly higher than the incidence in the normal population. These data would therefore seem to confirm the possibility of sexual transmission of hepatitis B.

Antibody Formation↗
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↗