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Biomedical subjects

M Ricci

Publications and source records attributed to M Ricci.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

[Our experience in pancreatic injuries].

Eight cases of pancreatic traumas are considered and the literature reviewed. Personal cases include: 1 contusion treated nedically; 2 cases of complete rupture (1 of which primary treated with double jejunal pancreatic anastomosis); 1 associated with splenic rupture, treated with distal pancreatectomy and splenectomy; 1 contusion of the head associated with hepatic lesions treated with suture of the lesions external derived and cholecystostomy; 4 contusions without lesion of the duct associated with other visceral lesions (stomach, duodenum, spleen, liver), treated surgically by suture of the lesion, and drainage of the omental bursa. As regards diagnosis, the only pathognomonic examination is amylasaemia. Paracentesis proved important in cases of haemoperitoneum. Long-term results were observed by scintigraphy and through starch and maltose load curves. Scintigraphy pointed to the presence of functional deficiency in areas which seemed to be only contused or actually normal. It is therefore concluded, especially in cases of complete rupture, that therapy should be kept as conservative as possible (Duodenal pancreatic anastomosis). The purpose of this is to prevent fistulas of the residual stump, fostered by the pressure in Oddi's sphincter, and to lease the pancreatic tissue as operative as possible. This is particularly important if patients are young.

Abdominal Injuries↗
PubMedDate not supplied

The torsion angle of the patellar tendon. A new CT parameter used for classification and treatment planning in femoropatellar syndrome.

The authors report a study conducted on 107 CT scans taken between January and December 2001 in 76 patients affected with femoropatellar pain, that did not benefit from physiotherapy. It is the purpose of this study to present a new CT scan parameter denominated torsion angle of the patellar tendon (TAPT) and to define an algorithm of treatment for this complex pathology based on the changes revealed by CT scan according to the Lyonese protocol. CT scan based on the Lyonese protocol provides an explanation of the symptoms and the objectivity via traditional parameters in 59.63% of patients. Thanks to the introduction of this new parameter (TAPT), which allows us to reveal the presence of an extrarotation of the proximal metaphysis of the tibia, the percentage of sensitivity with CT scan has been increased to 83.92%.

Adolescent↗
PubMedDate not supplied

[Assessment of the efficacy of limitations and indications issued by the occupational physician regarding the health of the staff working in public transportation vehicles].

In this study we assessed the evidence of some specific, "ad hoc", medical indications for city bus, tram and subway professional drivers. As known, professional drivers have very little chances of modifying shift organization and many chronic degenerative diseases (low back pain, diabetes type 2, cardiovascular diseases, ecc.) are difficult to manage according to job planning. In our study we observed a positive association between introduction of specific shift, in particular when shift is divided in two-piece, on morning "turno spezzato 1(0)/1(0)" or one on morning and the second part on afternoon "turno binato 1(0)/2(0)". Evidence of the real impact on professional drivers health conditions has been found from analysis of sickness leave during two, or in same case, one year before and after such medical indications intoduction. In our occupational drivers cohort a positive association, evidence based on real rates of two years sick absence before and after medical indications, was found between improvement of health general conditions and reduction of sickness leave rates correlated.

Adult↗
PubMedDate not supplied

Pathogenetic aspects of allergic respiratory syndromes.

Over the past twenty years great research effort has been made to clarify the pathogenetic mechanisms of allergic rhinitis (AR) and bronchial asthma (BA). The discovery of two types of Fc epsilon receptors (Fc epsilon RI and Fc epsilon RII) has made it possible to understand that allergic reactions can be due to interactions between allergens and cytophilic IgE bound not only by mast cells and basophils, but also by macrophages, lymphocytes, eosinophils and platelets. Knowledge of the complex mechanisms which regulate IgE antibody production has substantially improved since it was shown that IL-4 and T/B cell interactions are essential for the induction of human IgE synthesis, whereas IFN-gamma plays a negative regulatory role. In mice and humans, two types of helper T cells (Th1 and Th2) have been recognized, they produce different cytokines resulting in both cross-regulation of T cell function and B cell activity. In view of their particular pattern of cytokine secretion, Th2-type cells would be important in the specific response to allergens and in allergic inflammation. New knowledge about the mechanisms involved in the effector phase of allergic reactions and respiratory tract inflammation has recently been gained. In particular, the discovery of a complex network among cytokines, mediators and neuropeptides has offered the opportunity for advancing a new, integrative view of how the pathophysiological alterations responsible for respiratory allergic syndromes come about. We now realize that late phase allergic reactions, chronic allergic inflammation and tissue hyperreactivity are induced and maintained by a complex inflammatory mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMedDate not supplied

Adenosine enhances left ventricular flow during 24-hour hypothermic perfusion of isolated cardiac allografts.

Left ventricular flow progressively decreases during preservation of ex vivo hearts by continuous hypothermic perfusion, according to previous studies. This study was done to determine whether left ventricular flow could be maintained during 24-hour hypothermic perfusion by the addition of adenosine to the perfusate. Isolated canine hearts were perfused with either a modified Krebs-Henseleit solution or with the control solution containing adenosine (20 mumol/L) for either 4 or 24 hours. On completion of the perfusion period, radioactive microspheres were injected into the arterial inflow of the hearts. Myocardial samples were then taken from the endocardial, midcardial, and epicardial portions of the free wall and papillary muscles of the right and left ventricles, as well as the interventricular septum. Concentrations of radioactivity were determined for each sample, summed, and averaged for each ventricle. The ratio of average concentrations (L/R ratio) was significantly increased in the 24-hour adenosine hearts compared with 24-hour controls (1.10 +/- 0.15 vs 0.64 +/- 0.21, p less than 0.005). The L/R ratio of 4-hour controls (1.30 +/- 0.48) was also greater than that of 24-hour controls (p less than 0.005). These results suggest that left ventricular flow decreases during continuous hypothermic perfusion. The tendency toward diminished left ventricular perfusion after 24 hours is reduced when adenosine is added to the perfusate. Adenosine may be beneficial in ex vivo heart preservation with hypothermic perfusion by improving left ventricular flow.

Adenosine↗
PubMedDate not supplied

Role of interleukins in induction and regulation of human IgE.

The studies on human IgE synthesis here summarized provide further insight into the cellular and molecular mechanisms involved in IgE regulation, as well as in the alterations responsible for IgE disregulation in some pathological conditions. They have clearly demonstrated that IL-4 is the essential factor for the induction of human IgE synthesis, since no substantial IgE production in vitro could be obtained in the absence of this lymphokine. Another T cell-derived lymphokine, IFN gamma, negatively regulates the IgE synthesis induced by IL-4. These two lymphokines can be produced by different T helper cells, as shown in mice, but they can also be the product of the same T cell clones. In such a case, the possibility that a given clone provides helper function for IgE seems to be dependent on the balance between the amounts of the two lymphokines produced. The IgE helper activity of rIL-4 appeared to be dependent on the presence in culture of appropriate concentrations of T lymphocytes, suggesting that T-B cell contact or other interleukins, such as IL-2 and IL-6, are needed in IL-4-dependent IgE synthesis. Finally, alterations of one or more of these regulatory mechanisms may play a crucial role in the pathogenesis of diseases characterized by a hyperproduction of IgE.

Animals↗
PubMedDate not supplied

The Fc epsilon R2/CD23 antigen: a hallmark of chronic lymphocytic leukemia B cells.

The effect of different stimuli on the expression of the low-affinity receptor for the Fc fragment of IgE (Fc epsilon R2/CD23) on peripheral blood B cells from patients with chronic lymphocytic leukemia (CLL) was investigated. CLL B cells cultured for 3 days in medium alone showed a progressive decrease of the Fc epsilon R2/CD23 expression, while the addition to the cell cultures of IgE or interleukin-4 had a slackening effect on the decrease of the Fc epsilon R2/CD23. In contrast, in the presence of interferon-gamma the proportion of Fc epsilon R2/CD23+ cells was more rapidly reduced compared to CLL B cells cultured in medium alone. Stimulation of CLL B cells with Staphylococcus aureus Cowan I (SAC) bacteria, which are able to enhance the expression of Fc epsilon R2/CD23 on normal B cells, induced a rapid loss of the Fc epsilon R2/CD23 from CLL B cells.

Antigens, Differentiation, B-Lymphocyte↗
PubMedDate not supplied

New insights into the mechanisms which regulate IgE synthesis in man.

The studies summarized here provide further insight into the cellular and molecular mechanisms involved in the regulation of human IgE synthesis. They clearly demonstrate that IL-4 is the essential factor for induction of human IgE synthesis, since no substantial in vitro IgE production can be obtained in the absence of this lymphokine. Another T cell-derived lymphokine, IFN-gamma, negatively regulates the IgE synthesis induced by IL-4. These two lymphokines can be produced by different T helper cells, but they can also represent the product of the same T cell clone (TCC). In this case, the possibility that a given TCC provides helper function for IgE seems to be dependent upon the balance between the amounts of the two lymphokines produced. Additional cellular and/or molecular signals are involved in IL-4-dependent IgE synthesis. First of all, a direct T-B interaction is required to precede the activity of IL-4. This interaction does not necessarily consist of cognate interaction between T and B cells, as occurs for IgE synthesis induced by alloreactive TCC. In the presence of exogenous IL-4 virtually all CD4+, and even a number of CD8+, TCC can provide the signaling required by B cells to synthesize IgE. An interaction between some adhesion molecule, more expressed on activated than resting T cells, and its receptor on B cells is sufficient to prepare resting B cells to synthesize IgE in response to IL-4. Furthermore, T cells also contribute to IL-4-dependent IgE synthesis by releasing IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMedDate not supplied

Thyroiditis as a model of organ specific autoimmune disease.

In the last few years a great deal of information on the etiopathogenetic aspects of organ-specific autoimmune diseases has been obtained from the extensive study of both animal models of experimental or spontaneous thyroiditis and of human thyroid autoimmune diseases. It has been clearly shown that genetic factors play a fundamental etiologic role. They are responsible for the dysregulation of the immune system and for the target organ susceptibility which favor the onset of the disease. Environmental factors are presumed to act as initiating or precipitating events, leading genetically predisposed individuals to thyroid autoimmunity. A number of immune mechanisms able to trigger autoimmune responses, such as antigenic cross-reactions and the aberrant expression of HLA class II molecules, have been suggested, but the definition of why and how they become operative requires further investigation. Data obtained from experimental models and from human thyroid diseases clearly indicate that the ongoing expansion of autoreactive T cells with specificity for thyroid autoantigens represents the main immunological event responsible for induction and maintenance of thyroid damage. Such autoreactive T cells can induce tissue lesions through activation of different effector systems and secretion of different combinations of lymphokines. In overt thyroid autoimmune diseases autoantibodies directed against functional molecules or cellular receptors can also be involved in the pathogenesis of tissue lesions. However, the pathogenesis of inflammatory destructive lesions of the thyroid is more complex and not yet fully elucidated. It is worthy of note that a large proportion of T cells present in inflammatory human thyroid infiltrates are apparently not directed against the thyroid autoantigens recognized so far.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗