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Biomedical subjects

M Ricci

Publications and source records attributed to M Ricci.

At least 235 records · Page 13Linked to original sources
PubMed1980

Labelling of blood platelets with stable tracers.

Half-time values of platelets labelled with stable rubidium are compared to those of platelets labelled with Cr51. Platelets labelled with stable rubidium are assayed by a very simple version of the X-Ray fluorescence equipment. The mean quantity of rubidium incorporated by the cells is of about some microgram Rb per ml blood. The in vitro half-time of human Rb labelled platelets stored at 22 degrees C is 41.2 +/- 3h compared with the value 44.8 +/- 3h for platelets labelled with Cr51, as deduced by six experiments. The in vivo half-time of rabbit platelets labelled with stable rubidium is 22 +/- 3h compared with the value 18 +/- 3h of platelets labelled with Cr51; ten experiments were carried out.

Animals↗
PubMed1980

[Two-time traumatic rupture of the gallbladder].

Two cases of traumatic perforation of the gallbladder following open and closed injury to the abdomen respectively are described. Their common feature was a long, oligosymptomatic free interval. A brief account is given of the aetiopathogenetic, clinical and therapeutic problems raised by cases of this kind.

Abdominal Injuries↗
PubMed1980

The use of computed tomography in the diagnosis of coronary artery bypass graft patency.

In a preliminary evaluation of the use of dynamic computed tomography (CT) for the detection of patent aortocoronary bypass grafts, 30 patients were scanned either during the early postoperative period or after graft patency was determined by angiography. To visualize the proximal grafts, CT scans were taken through the aortic root following an intravenous bolus injection of contrast medium. Patent bypass grafts to the left anterior descending and right coronary arteries were demonstrated in 77.5%, while posterior grafts to the circumflex and obtuse marginal coronary arteries were detected in 40%. With its potential for extracting dynamic events, CT scanning provides a new, noninvasive modality for the diagnosis of patent bypass grafts, which heretofore have only been visualized by selective angiography.

Adult↗
PubMed1980

Hyperproduction of IgE and T-cell dysfunction in Hodgkin's disease.

Serum IgE levels were evaluated in 119 untreated and 112 treated patients with Hodgkin's disease (HD). 38 of the nonatopic untreated patients showed significantly increased (> 300 IU/ml) IgE concentrations. No relationship could be found between increased IgE levels and depressed lymphocyte response to phytohemagglutinin (PHA) or the imbalance of TM and TG lymphocyte subsets. On the other hand, the mean level of suppressor activity elicitable from cells of untreated HD patients by concanavalin A preincubation did not differ significantly from that of healthy control subjects. In contrast, in treated patients, where there was a significant reduction in the number of circulating T lymphocytes, a further depression of the lymphocyte response to PHA, a more marked disproportion of TM and TG cell subsets and a noticeable fall in IgE concentration was found. These data suggest that increased IgE concentrations seen in untreated patients with HD are unrelated to the T-cell defects. They also suggest that hyperproduction of IgE is probably not invariably a consequence of a suppressor cell deficiency.

Cell Division↗
PubMed1980

T-cell independence of immunoglobulin synthesis by human peripheral blood lymphocytes stimulated with SpA-containing staphylococci.

Unfractionated and T-cell depleted human peripheral blood lymphocytes (PBL) were cultured in vitro in the presence of pokeweed mitogen (PWM) and Staphylococcus aureus strain Cowan I (StaCw). After 7 days of culture, the cells were assayed for cytoplasmic immunoglobulins (Cyto-Ig) by direct staining using fluorescein-labelled F(ab')2 fragments prepared from specific antisera against human IgG F(ab')2. The amount of immunoglobulin of the IgM and IgG class released into the cell-free supernatants was also measured by radioimmunoassay. In unfractionated PBL StaCw, like PWM, was able to induce a significant increase of either the number of Cyto-Ig containing cells for the amount of IgM and IgG secreted into the supernatant. In contrast, the amount of IgM and IgG immunoglobulin released into the supernatant of T-cell depleted suspensions stimulated with PWM was significantly reduced in comparison with that of unfractionated populations, whereas it was unchanged in T-cell depleted vs unfractionated suspensions stimulated with StaCw. The addition of a few T lymphocytes restored the ability of T-cell depleted suspensions to produce Ig in the presence of PWM, whereas despite addition of high numbers of T cells no further augmentation of the Ig production induced by StaCw on T-cell depleted suspensions was observed. Cultures of umbilical cord blood lymphocytes (UCBL) stimulated with PWM did not generate Ig-producing cells, whereas UCBL stimulated with StaCw showed significant production of Ig of both IgM and IgG classes. The results indicate that T lymphocytes are probably not involved either with stimulation or with the suppression of Ig production induced by StaCw.

Adult↗
PubMed1979

A simple solid-phase radioimmunoassay for the measurement of IgG secreted in vitro by human lymphocytes.

A radioimmunoassay is described for measuring IgG, based on the ability of immunoglobulins of this class to inhibit the binding of radioiodinated staphylococcal protein A to IgG linked to a solid phase. The solid phase is represented by ox erythrocytes coated with anti-ox erythrocyte rabbit IgG, a reagent used for detecting cells equipped with receptors for the Fc fragment of IgG. By this assay the IgG secreted in vitro by human peripheral blood lymphocytes stimulated with PWM and those present in samples of very diluted human sera were measured. It was found that the assay is a very rapid, simple and reproducible procedure for the detection of IgG immunoglobulin at the nanogram level.

Animals↗
PubMed1979

Study of some properties of the receptor for IgM on human lymphocytes.

Some properties of the receptor for IgM on human lymphocytes have been investigated. It was shown that the interaction of native IgM with the receptor present on T and B lymphocytes is not critical for its detection in the EAM-rosette assay. In fact, high values of EAM-RFC could be found on cell suspensions cultured overnight in either IgM-free or IgM-containing media. In addition, the inhibition of EAM-rosettes by human monoclonal IgM at 37 degrees C was not as effective as at 4 degrees C. Rabbit IgM showed a significantly greater ability to inhibit the binding of antigen-IgM antibody complexes than human IgM. The receptor for IgM was easily removed by handling procedures, the incubation of lymphocytes at 4 degrees C and treatment of the cells with low concentrations of trypsin or pronase. After the enzymatic treatment, a rapid resynthesis occurred, which restored the number of EAM-rosettes formed by T cells and significantly increased the number formed by B cells. The interaction between the receptor and antigen-IgM antibody complexes stopped the spontaneous shedding of the receptor at 4 degrees C. When the incubation of the cells with immune complexes was performed at 37 degrees C, a significantly different behaviour between T cells equipped with receptor for IgM and those possessing receptor for IgG was found. After the binding of EAG to the receptor for IgG, a process of rapid dissociation of rosettes occurred, whereas the incubation with EAM did not induce an irreversible loss of the receptor for IgM.

Antigen-Antibody Complex↗
PubMed1978

Altered proportion of T mu-and T gamma-cell subpopulations in patients with Hodgkin's disease.

The ability of peripheral blood lymphocytes from patients with Hodgkin's disease (HD) to form rosettes with ox red blood cells (ORBC) sensitized by anti-ORBC purified rabbit IgM and IgG was investigated. The mean percentage of cells capable of forming rosettes with ORBC coated with IgM (EAIgM-RFC) in the peripheral blood of either untreated or X-ray-treated patients with HD was significantly lower than that of normal individuals. In the same groups of patients with HD the mean percentage of T lymphocytes equipped with receptor for IgG (T gamma lymphocytes), evaluated by a mixed fluorescent rosette assay, was significantly higher than in normal controls. These data suggest that the altered proportion between T mu-and T gamma-cell subpopulations in patients with HD probably represents a disease-related phenomenon.

Adolescent↗
PubMed1978

Receptors for IgM: a feature of subpopulations of both T and B human lymphocytes.

Receptors for IgM were detected on peripheral blood and tonsil human lymphocytes by a rosette technique with ox red blood cells (ORBC) coated with anti-ORBC rabbit IgM. It was found that the receptors are very sensitive to handling procedures of cells and to low temperatures. An overnight incubation period at 37 degrees C was the optimal condition for the maximum expression of receptors for IgM, but the use of IgM-free media in these cultures was neither an essential nor favourable factor for an optimal rosette formation, when ORBC heavily coated with rabbit IgM were used. The great majority of chronic lymphocytic leukaemia (CLL) patients presented a high number of EA(IgM)-RFC, either on freshly drawn or cultured lymphocytes. By fractionation procedures of normal peripheral blood and tonsil lymphocytes, it was found that a subpopulation of B cells, like T cells, also posses a lower avidity for IgM than those present on T lymphocytes.

B-Lymphocytes↗
PubMed1978

Different mitogenic activity of soluble and insoluble staphylococcal protein A (SPA).

The response to SPA and Staphylococcus strain Cowan I (StaCw) of highly purified populations of peripheral blood and tonsil human lymphocytes was investigated. Purified T lymphocytes isolated from perpheral blood by E-rosetting were unable to respond in vitro to StaCw. Highly purified B-cell populations from tonsils did not show any proliferative response in the presence of soluble SPA. The addition to highly purified B-cell suspensions from human tonsils of increasing concentrations of autologous T lymphocytes did not induce any increase of thymidine uptake in the presence of StaCw. However, it was able to restore a marked proliferative response of the B-cell cultures to soluble SPA, even though mitomycin-treated T lymphocytes were added. The low response of highly purified peripheral blood T lymphocytes to soluble SPA could be potentiated by the addition of autologous mitomycin-treated B cells, whereas the unresponsiveness of purified T lymphocytes to StaCw was not affected. Mitogenic activity of SPA coupled to Sepharose beads was different from that of soluble SPA and paralleled that of StaCw. These data strongly suggest that insoluble SPA is a T-cell-independent B-cell mitogen in man, whereas soluble SPA, like PWM, exerts its activity on B cells only in the presence of T cells.

B-Lymphocytes↗
PubMed1978

[Preventive intervention during the planning of a new factory: contribution of an occupational medicine service on installation of a ceramic dye-producing plant].

The control during the planning of a factory is a sort of prevention. For instance, we suggested industrial hygiene standards for a new chemical plant, which have been into account. According to our suggestions they set up a closed factory process, a dust and fumes filtering plant and the water recycle. After some controls outside the factory, lead and dust concentrations were below the maximum allowed levels (30 and 5 mg/Nmc).

Air Pollutants↗