Search PubMed⌕ Search

Biomedical subjects

M Di Renzo

Publications and source records attributed to M Di Renzo.

At least 19 recordsLinked to original sources
PubMed2001

A photoacoustic FTIRS study of the chemical modifications of human dentin surfaces: II. Deproteination.

This work focuses on the chemical alterations occurring on the dentin surface on treatment with sodium hypochlorite (NaOCl), a known deproteinating agent. In addition, sequential treatment with both acid and NaOCl are characterized. Modifications are evaluated using photoacoustic FTIR (PA-FTIRS), a surface-sensitive spectroscopy. Spectra of NaOCl-treated dentin samples show a slow and heterogeneous removal of its organic phase, leaving calcium hydroxyapatite and carbonate apatite unchanged. Spectra of this deproteinated surface resemble those of apatites synthesized at low temperatures and having very high-surface areas. A combined sequential 2-min treatment of dentin with both maleic acid and NaOCl indicates that this treatment can produce a surface region which is neither significantly demineralized nor deproteinated. This sequential treatment can be used to remove the smear layer and restore the dentin surface to its natural composition.

Acid Etching, Dental↗
PubMed2001

A photoacoustic FTIRS study of the chemical modifications of human dentin surfaces: I. Demineralization.

Acids are used to modify the structure and composition of dentin surfaces to improve bonds formed with resins. The purpose of this work is to investigate such chemical modifications using the surface-sensitive technique photoacoustic Fourier transform infrared spectroscopy (PA-FTIRS). Spectra of acid-treated samples (citric, maleic, nitric, and phosphoric at pH = 1.0) were recorded at various time intervals. Analysis of these spectra indicates a gradual increase in sample surface area with treatment time. A decrease of the bands associated with calcium hydroxyapatite (HAP) and carbonate apatite inherent to the mineral phase of dentin are also observed. A comparison of spectra of samples treated for 2 min with each acid also reveals that maleic and phosphoric acids remove more HAP than citric acid. We conclude that citric acid may cause the formation of precipitates at the etching front which inhibit etching.

Acids↗
PubMed2000

Elastofibroma dorsi.

It is often difficult to identify the characteristics of soft-tissue tumors of the chest wall. This paper describes the peculiarities of elastofibroma dorsi, a rare pseudotumor of this site, to exclude many dangerous misconceptions. During the period between 1987 and 1997, we treated nine patients with elastofibroma dorsi. In six patients, the lesion was unilateral and in three it was bilateral. All these lesions were excised and no evidence of local recurrence or shoulder disability was observed at the last clinical evaluation. Elastofibroma dorsi is a rare, slow-growing, pseudotumoral lesion of the soft tissues of the chest wall with a peculiar radiographic and histologic pattern.

Aged↗
PubMed2000

Enhanced apoptosis of T cells in common variable immunodeficiency (CVID): role of defective CD28 co-stimulation.

CVID is a primary immune disorder in which hypogammaglobulinaemia may be associated with a number of T cell defects including lymphopenia, anergy, impaired lymphocyte proliferation and deficient cytokine secretion. In this study we show that T cells of CVID subjects, in comparison with control T cells, undergo spontaneous apoptosis in culture and markedly accelerated apoptosis after gamma-irradiation. Although costimulation of the CD28 receptor following engagement of the TCR/CD3 receptor normally provides a second signal necessary for IL-2 secretion, CD28 costimulation in CVID does not significantly increase IL-2 production, nor does this combination of activators enhance the survival of irradiated CVID T cells, as it does for cultured normal T cells. Addition of IL-2 enhances CVID T cell survival, suggesting that the IL-2 signalling pathways are normal. CVID T cells have similar expression of Bcl-2 to control T cells. CD3 stimulation up-regulates T cell expression of bcl-xL mRNA for normal T cells, but anti-CD28 does not augment bcl-xL expression for CVID subjects with accelerated apoptosis. Defects of the CD28 receptor pathway, leading to cytokine deprivation and dysregulation of bcl-xL, could lead to poor T cell viability and some of the cellular defects observed in CVID.

Adolescent↗
PubMed1998

POEMS syndrome with vascular lesions and renal carcinoma - possible role of cytokines.

We describe here the case of a 60 years man with POEMS syndrome associated with renal tumor and vascular lesions. The patient had osteosclerotic myeloma IgA-lambda, polyneuropathy, endocrinopathy and skin changes. In addition, he developed renal clear cell carcinoma and gangrena of lower limbs. The humoral study showed thrombocytosis, high levels of IL-1beta and IL-6 and of some coagulative/fibrinolytic and endothelial factors (von Willebrand factor, plasmin-antiplasmine complexes, plasminogen activator). We suggest the hypothesis that these factors are capable of determining some manifestations of POEMS syndrome.

Adenocarcinoma, Clear Cell↗
PubMed1998

[Granulomatous prostatitis as collateral effect of intravesical immunotherapy with BCG].

Twenty-five male patients with superficial bladder cancer underwent intravesical Bacillus Calmette Guerin immunotherapy. A high incidence of side effects has occurred using three different substrains of BCG. Our interest has been focused on BCG related granulomatous prostatitis: we have found four asymptomatic patients with histologically diagnosed disease. We suppose therefore that its incidence is underestimated.

Adjuvants, Immunologic↗
PubMed1997

Extracorporeal photochemotherapy restores Th1/Th2 imbalance in patients with early stage cutaneous T-cell lymphoma.

Extracorporeal photochemotherapy (ECP) has been shown to be a potent activator of peripheral blood macrophages because it causes a marked release of macrophage-dependent proinflammatory cytokines, and it is therefore currently considered to be a safe and non-toxic immunomodulatory treatment. On this basis we studied the function of peripheral blood mononuclear cells (PBMC) in eight patients with early stage (Ib) cutaneous T-cell lymphoma (CTCL), before and 1 year after ECP, together with their clinical and histological responses. In particular we evaluated in vitro phytohaemagglutinin (PHA)-stimulated proliferation and production of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) as well as lipopolysaccharide (LPS)-induced production of IL-12. Before treatment we observed that PBMC of patients produced significantly higher levels of IL-4 and lower levels of IFN-gamma and IL-12 than those of healthy control subjects. After 1 year of ECP, IL-4, IFN-gamma and IL-12 production no longer differed from that of control subjects. Moreover, we observed a good clinical result matched by histological response. Our data confirm that early-stage CTCL patients show a predominantly type-2 immune response that might be responsible for several immunological abnormalities found in this disease. We have demonstrated that ECP reverses the T-helper type 1/T-helper type 2 (Th1/Th2) imbalance and may therefore be considered an efficient biological response modifier.

Aged↗
PubMed1997

The in vitro effect of Pidotimod on some immune functions in cancer patients.

There are several reports concerning an impairment of cellular immune response in patients affected by malignant disease. The aim of this study was to evaluate the in vitro effect of Pidotimod, a synthetic biological response modifier, on some immune functions in 14 cancer patients. In particular, we showed that these subjects had a significantly reduced peripheral blood mononuclear cell (PBMC) proliferation both in response to PHA and to Con A in comparison with a group of healthy subjects. Besides, they showed a significantly reduced PBMC IL2 production, which was evaluated both through an ELISA method and a biological assay. The in vitro addition of increasing concentrations of Pidotimod (10, 25 and 50 ug/ml) was able to enhance PBMC proliferation and IL2 production significantly. However, in spite of the addition of Pidotimod, both immune functions in our neoplastic patients did not reach normal values.

Adjuvants, Immunologic↗
PubMed1995

Imipenem and immune response: in vitro and in vivo studies.

Imipenem is a new beta-lactam antibiotic endowed with very high antimicrobial activity; it is used in severe infections which often occur in those conditions characterized by impairment of the immune system. The aim of this study was to evaluate the effect of imipenem on some immune functions, both in vitro and in vivo. The authors studied the effect in vitro of three different drug concentrations (15, 30 and 60 mg/l) on polymorphonuclear leucocyte (PMN) phagocytosis and superoxide anion production, as well as on lymphomonocyte proliferative response and cytokine production. Preincubation of PMN with the highest dosages (30 and 60 mg/l) was found to increase phagocytosis evaluated via both cytofluorimeter and chemiluminescence, while no effect was detected on superoxide anion production or on lymphomonocyte tests. In the in vivo study, the authors administered imipenem/cilastatin (1500 mg/day) to 15 elderly and diabetic patients, in whom both PMN functions (phagocytosis and superoxide anion production) and lymphocyte tests (CD3, CD4, CD8, CD19, IL2 and sIL2R serum levels) were studied before and on the 3rd and 7th days of treatment. The drug assimilation did not modify the lymphocyte parameters, whereas it increased PMN superoxide anion production and phagocytosis which were depressed in basal conditions. In the former case, such increase was slight and insignificant, whereas in the latter it was significant.

Aged↗
PubMed1995

Changes of some immune functions after percutaneous transluminal coronary angioplasty (PTCA).

This study aimed to evaluate some aspects of the immune response in 10 cardiopathic patients during the execution of percutaneous transluminal coronary angioplasty (PTCA) by obtaining blood samples from coronary sinus. In particular we considered some PMN functions as well as lysosomal release and oxidative metabolism evaluated as chemiluminescence and superoxide anion (O2) production. We also studied serum levels of complement C3 and C4, lymphocyte populations (CD3, CD4, CD8, CD19, CD16) and plasmatic determinations of interleukin 2 (IL2). After PTCA, we found a decrease of total count of blood lymphocytes, whereas the number of neutrophils remained unchanged. The decrease involved to a similar extent the lymphocyte subsets CD3, CD4 and CD8, whereas CD19 and CD16 were unchanged. The plasmatic levels of IL2 did not show any significant modification. Concerning PMN, their chemiluminescence was significantly increased after PTCA as compared to basal values: this response was promptly detectable in isolated PMN, both without and with stimulation with fMLP. Similarly superoxide anion production, both spontaneous and stimulated, was increased in PMN suspensions after PTCA, even if this increase did not reach statistical significance. As regards circulating levels of lysosomal enzymes, we found a significant increase of plasmatic levels of elastase, whereas the serum determinations of lysozyme and betaglucuronidase did not change. Concerning the complement system, we found a significant decrease of complement fractions C3 and C4. In conclusion, our results showed certain changes in some humoral and cellular systems; in particular the neutrophil activation through the release of proteolytic enzymes and the generation of oxygen radicals could increase the damage to vessel walls and activate other systems having a negative effect in the ischaemia-associated consequences.

Angioplasty, Balloon, Coronary↗
PubMed1994

Pharmacodynamics and pharmacokinetics of Veliten (rutine, alpha-tocopherol and ascorbic acid) in patients with chronic venous insufficiency.

The aim of this study was to evaluate the pharmacodynamics and pharmacokinetics of a single oral dose of Veliten in 12 patients affected by chronic venous insufficiency. In particular, the pharmacokinetics of two components of Veliten, namely rutine and alpha-tocopherol, were considered, while with respect to pharmacodynamics, studies were made of venous function, haemocoagulative and fibrinolytic balance, and haemorheological parameters. Correlation between such changes and plasma drug levels was also evaluated. We found a significant increase of venous tone, venous capacity and venous distension after drug intake, as well as a significant activation of fibrinolysis (globally evaluated with euglobulin lysis time), related to a slight increase of plasminogen tissue activator. These changes appeared concomitantly with maximal plasma levels of rutine. We did not find any modifications of coagulative and haemorheological parameters.

Administration, Oral↗
PubMed1991

Clinical study on pharmacological interaction between nimesulide and warfarin.

This article describes the pharmacological interaction between nimesulide, a recently introduced non-steroidal anti-inflammatory drug, and warfarin, an indirect anticoagulant. The aim of the study was to demonstrate if nimesulide could potentiate the activity of this anticoagulant drug, as previously shown by some authors. Ten patients, who were taking 5 mg/day of warfarin, were treated with nimesulide 100 mg twice a day, for seven days: the association of the two drugs did not alter, in a statistical way, neither prothrombin time, nor partial thromboplastin time, nor fibrinogenemia, nor bleeding time. The findings showed that, in a short-term treatment, there was no bleeding risk in combining warfarin with nimesulide.

Adolescent↗
PubMed1991

Effect of cefodizime (HR 221) on immunological defects induced by surgical stress.

Cefodizime, a new aminothiazolylcephalosporin, has been shown to possess immunomodulating activity in many experimental models in vivo and in vitro. The in-vivo effect of the drug was evaluated in a model represented by the surgical patient, being surgical practices usually associated with an immunological impairment involving many aspects of the immune response. Two groups of ten subjects were treated respectively with cefodizime (2 g i.v. daily) and another cephalosporin (ceftriaxone) at the same dosage. Aspecific immunity (complement activity, neutrophil phagocytosis, chemiluminescence and superoxide anion production) and cell-mediated reactivity (lymphocyte subpopulations and E-rosette-forming cells) were evaluated before, and at predetermined intervals after, surgery and antibiotic treatment. In the control group an important immunological derangement is observed, involving both lymphocytes and neutrophil functions and complement system. The treatment with cefodizime displays a positive effect with a significant improvement of impaired functions. The effect of the drug particularly influences neutrophil phagocytosis, explored with both the NBT test and determinations of chemiluminescence, and the complement system, through both the classic and the alternative pathways. A slight effect is observed on lymphocyte functions.

Adolescent↗
PubMed1983

Immunofluorescence study of fibronectin distribution in the developing chick embryo striated muscles.

This paper reports immunofluorescence data concerning fibronectin distribution in chick embryo striated muscle buds, i.e. myotomes and heart bud, in stages following their differentiation. At earliest developmental stages (12-15 HH) no fibronectin could be observed between the still poorly differentiated myoblasts of myotomes and of the splanchnopleure. Fibronectin, however, was observed among differentiated myoblasts of the myocardial ventral portion. In myotomes at later stages (16-18 HH), a few thin strands of fibronectin were observed between the myotomal and dermatomal laminae; this pattern became more marked between stages 17 and 26 HH. It is concluded that during myogenesis, fibronectin is absent at the earliest differentiation stages. A faint fibronectin-containing matrix is detectable at later stages and becomes more evident only in mature muscle tissue. This pattern is consistent with a role of fibronectin in the process of tissue organization.

Animals↗
PubMed1978

[A chromatographic method for the urinary pregnanediol dosage for routine analyses (author's transl)].

The AA. aiming at a handy and speedy system admitting of being fitted to the equipments of any laboratory hospital have taken into account two procedures, one proposed by Varley and the other of Fotherby and Love reported by Wootton and King for pregnanediol. The two methods have been combined in order to make the process easier. The procedure is based upon chromatography on alumina of ethereal extracts dissolved in cyclohexan. Glucuronate hydrolysis has been obtained with beta-glucuronidase.

Chromatography, Gel↗
PubMedDate not supplied

Evaluation of some immune functions in a patient affected by common variable immunodeficiency using luminescent techniques.

Common variable immunodeficiency is a primary immunodeficiency characterized by a failure of antibody synthesis, whose fundamental immunologic abnormality is still unknown. In our study, we evaluated some immune functions using chemiluminescence in a 32-year-old woman affected by common variable immunodeficiency. In particular, we showed an impairment of her lymphomonocyte proliferative response which was evaluated using a method based on the bioluminescent measurement of ATP. Besides, we found a reduction of her lymphomonocyte IL2 and IL4 production: the IL4 production was evaluated through an ELISA method, whereas the IL2 activity was determined by its ability to support the IL2-dependent murine T-cell line (CTLL) proliferation which was established through a method based on the bioluminescent measurement of ATP. Finally, we evaluated both yeast-induced and fMLP-induced polymorphonuclear and monocyte oxidative metabolism through a luminol-amplified chemiluminescence; these functions were within normal values. Therefore, in our patient affected by common variable immunodeficiency, we demonstrated an impairment of cellular immunity, which might contribute to the pathogenesis of the disease.

Adenosine Triphosphate↗