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Biomedical subjects

M Ricci

Publications and source records attributed to M Ricci.

At least 253 records · Page 14Linked to original sources
PubMed1977

[Perforations of the small intestine].

Six cases of perforation of the small intestine, one secondary to anaphylactoid purpura and five spontaneous, are reported. Ingestion of an iced drink acted as a trigger in two cases. A vascular genesis is put forward to explain the aetiopathogenesis of two cases and it is noted that perforation of this type is present in the final ileal ansa, at the mesenterial margin. In three cases, histology revealed the presence of double refraction crystal. These came from vegetal residues and are probably capable of penetrating from the lumen into the mucosa causing a foreign body reaction, abscess and subsequent perforation. In these cases, perforation occurred in an ansa located further away than the last ileal ansa (about 3 m) and on the mesenterial margin. Intestinal resection and subsequent end-to-end, single layer anastomosis were performed in all cases.

Child, Preschool↗
PubMed1977

Co-operation between T and B lymphocytes from human tonsils in the response to mitogens and antigens.

Purified B lymphocytes obtained from human tonsil cell populations by removing E rosette-forming cells by density sedimentation did not proliferate at three days in response to PHA and Con A, but showed a significant 3H-labelled thymidine incorporation when the PHA response was assessed at day 6 of culture. The 6th-day responses, which was completely abolished by the reduction of T-cell contamination to less than 0-1% by re-rosetting and a second separation, was due in part to a direct activation by PHA of contaminating T cells and in part to a T cell-mediated B-cell response. When purified B cells were stimulated for 3 days by PHA in the presence of an equal number of autologous or homologous mitomycin-treated T lymphocytes a highly significant uptake of 3H-labelled thymidine was demonstrated. The majority of blast cells obtained at day 4 in these cultures were unable to form E rosettes and showed surface immunoglobulin by immunofluorescence stain. This response was markedly decreased by previous treatment of B cells with mitomycin C and it was abolished when B cells were killed by heating at 56degrees C for 1 hr. Purified B lymphocytes from human tonsils did not respond in vitro when cultured for 6 days in the presence of soluble antigens (PPD and Candida). However, a highly significant response to the same antigens could be demonstrated when B cells were cultured in the presence of autologous mitomycin-treated T cells. These models of T-B co-operation could provide an interesting tool for studying the differentiation and antibody production in vitro of human B lymphocytes.

Antigens, Bacterial↗
PubMed1977

[Long term results of surgical treatment for aneurysms of the abdominal aorta].

A series of 100 consecutive patients operated on for an abdominal aortic aneurysm, whether cold or as emergency, but excluding those cases with circulatory collapse, has enabled us to define the post-operative prognosis after a follow-up of a maximum of ten years. The operative mortality of 12% was due essentially to coronary and renal complications. All of the survivors, except one, were available for review. Five years after the operation 64% were still alive, and the figure was 46% at eight years. These figures confirm the indication for systematic surgical treatment as soon as an aneurysm is discovered, unless any of the contra-indications which are discussed are present. The best method of following up small aneurysms (with a diameter of less than 6 cms) discovered in elderly subjects would be by echotomography.

Aged↗
PubMed1976

Studies on allergens of Dermatophagoides pteronyssinus by direct and indirect RAST.

Dermatophagoides pteronyssinus (DP) extract was fractionated by Sephadex G-75 and liquid isoelectric focusing (IEF) and the allergenic activity of different fractions was monitored by direct and indirect RAST. The fractionation on Sephadex G-75 showed that the allergenic activity of DP extract was related to wide molecular weight spectrum components, even though the maximum amount was recovered in effluent that contained protein with a molecular weight ranging between 25,000 and 12,500 daltons. By fractionation of the mite extract on IEF, three main peaks of allergenic activity (pI less than 3.0; pI = 4.3 +/- 0.25; pI = 6.4 +/- 0.25) were found. Cross-inhibition experiments showed a high degree of cross-reactivity between allergenic material eluted in very distant regions of molecular weight or isoelectric point. The allergenic activity of unfractionated mite extract and of its IEF fractions was destroyed by pronase - but not by neuraminidase - treatment. These results suggest that DP extract probably contains one main allergen existing in multiple molecular forms rather than several distinct allergens and that a protein moiety of the allergen is necessary for the combination with IgE.

Absorption↗
PubMed1976

In vitro lymphocyte response to the phytomitogens in untreated and treated patients with Hodgkin's disease.

In vitro lymphocyte response to phytohemagglutinins (PHA), concavalin A (Con A), and pokeweed mitogen (PW) was evaluated in untreated and treated patients with Hodgkin's disease (HD). The responding capacity to PHA was depressed, though not constantly, in the untreated patients compared with the response to lymphocytes from normal individuals. The depression was more evident, at group level, when the cells were stimulated with suboptimal concentrations of PHA. Radiotherapy constantly induced a strong decrease or a complete loss of the responding capacity of the cells which persisted at low levels for many months. Some years after the initial course of treatment, the response was clearly depressed, but it was better in patients in remission than during relapse. Splenectomy did not affect the responding capacity of the cells. The depressive effect induced by chemotherapy was apparently less marked and persistent than that of radiation. Con A- and PW-induced lymphocyte transformation usually paralleled the PHA-induced response. The depressed response to PHA was not due to an inhibitory activity of HD serum. Washed HD lymphocytes in fetal calf serum were not stimulated better than in autologous plasma, nor were HD sera able to depress the response of normal lymphocytes to PHA, Con A, PW, and PPD. Supernatants from HD lymphocytes cultured for 24 h without any stimulant, and extracts of these cells were also unable to affect the response of normal lymphocytes to PHA.

Adolescent↗
PubMed1975

[Immunological aspects of bronchial asthma].

Advances in understanding of bronchial asthma are to be expected from more detailed information on the immuno-pathological mechanisms involved. Reaginic IgE antibodies are responsible for the great majority of extrinsic asthma, but in some cases immune complexes could probably be also important. A great progress has been achieved after reproducible methods for detecting cellular and serum specific IgE antibodies were introduced. Moreover, the immunological and biological changes induced by immunotherapy are better known. Standardization and purification of allergenic extracts is now under study in many laboratories, our own included. As concerns the intrinsic asthma attempts to demonstrate the importance of (auto) immune mechanisms have been performed. The results of these studies are reported.

Antibody Formation↗
PubMed1975

Mites and house dust allergy. IV. Antigen and allergen(s) of Dermatophagoides pteronyssinus extract.

The antigenic composition of D. pteronyssinus extract was investigated by using antisera raised in rabbits by injection of the mite extract in Freund's adjuvant. Immunodiffusion analysis revealed the presence in the mite extract of many antigenic constituents, most of which were also common to human dander and house dust extracts. Four antigenic components not shared by human dander appeared to be common to D. farinae extract. D. pteronyssinus extract was then fractionated on Sephadex G-75 and DEAE-Sephadex. Immunodiffusion analysis of the most active fraction revealed, after heat-treatment, the presence of three precipitin lines, one of which appeared not to be shared by nutrient medium or by D. farinae extract constituents. When the anti-mite rabbit serum was fixed to an immunosorbent and incubated with a house dust extract it was constantly able to induce a strong decrease or a complete loss of the allergenicity of the dust extract in man. These results suggest that mite allergen(s) are immunogenic in the rabbit and provide more direct evidence for identity of the allergens in house dust and mite.

Allergens↗
PubMed1975

Depression of grass pollen-induced lymphocyte transformation by serum from hyposensitized patients.

Serum from grass-sensitive patients who had received hyposensitization therapy was found able to depress the in vitro response to Holcus lanatus grass pollen extract of lymphocytes from untreated grass-sensitive individuals. The inhibitory activity could no longer be demonstrated at serum dilutions equal to or greater than 1/100 and was not seen when the cells were stimulated with PHA or unrelated antigens. It was contained in the precipitated fraction of 33% saturated ammonium sulphate-treated serum, segregated with the 7S peak of Sephadex G-200 and with the IgG fraction of DEAE-Sephadex-fractionated serum and could be removed by the absorption of the serum with the Holcus lanatus allergenic extract. These data suggest that the serum factor responsible for the depressed in vitro lymphocyte response to the allergen in hyposensitized patients was a 7S IgG antibody induced by immunotherapy.

Bacterial Proteins↗
PubMed1975

[Atopy today].

Explore the source record for details and available documents.

Animals↗
PubMed1975

Antigenic and allergenic constituents of Dermatophagoides pteronyssinus extract.

The antigenic analysis of Dermatophagoides pteronyssinus extract was performed by using antiserum obtained in rabbits by immunization with mite extract in Freund's adjuvant. Immunodiffusion and immunoelectrophoretic analysis revealed the presence of many constituents, most of which were common to human dander, house dust and Dermatophagoides farinae extracts. By fractionation of the mite extract on Sephadex G-75 and DEAE-Sephadex it was shown that the highest allergenic activity was related to a family of heat-stable molecules weighing about 30,000. The antigenic analysis of chromatographic most active fraction revealed the presence of three heat-stable constituents, one of which is not shared by nutrient medium, or by D. farinae extract. The fractionation of D. pteronyssinus extract by preparative isoelectrophocusing on sucrose gradient (pH range 3-10) showed that the two fractions (pH 3.5 and pH 5.0) containing the major allergenic activity (measured by the RAST-inhibition capacity) were also able to induce a significant in vitro activation of lymphocytes from allergic patients. When the anti-mite rabbit gammaglobulins were fixed to an immunosorbent and incubated with a house dust extract, it was constantly possible to induce a strong decrease or a complete loss of allergenicity of the dust extract in man. This is in favour of an allergenic identity between dust and mite.

Allergens↗
PubMed1975

[Caliceal diverticula].

The Authors describe a case of calycial diverticulum which came under their observation, discussing the aetiopathogenetic and anatomopathological factors and the mechanisms supporting this pathological event. They conclude that it must be considered as of congenital origin and generally treated with conservative therapy, limiting the use of demolitive surgical therapy solely to cases of deep and diffused alteration of the kidney.

Adult↗