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Biomedical subjects

S Rizzo

Publications and source records attributed to S Rizzo.

At least 55 records · Page 3Linked to original sources
PubMed1998

Morphology of peri-implant regenerated bone, in sheep's tibia, by means of guided tissue regeneration.

BACKGROUND: No data on the resistance to functional loads of bone regenerated by means of guided tissue regeneration, can be found. In this paper the new-formed bone is analyzed, in cases that see the surgical creation of defects in testing animals. The morphological aspects of perimplant bone, regenerated by means of bone substitutes or not, were evaluated. METHODS: A coronal defect was created by means of a counter-sink bur. The following step provided for osseointegrated fixtures, with a machined or blasted (TiOblast) surface, to be installed. Some bone defects were filled with Bio-Oss, and covered with resorbable membrane (Vycril), others were left unfilled. The animals were sacrificed after different periods of time (24 and 45 days). Some thick sections (200 microns) underwent then microradiography and were examined with a microscope, under transmitted and polarized light. Other sections, thin (5 microns), were coloured with toluidine blue, Gomori's Stain and Solochrome Cyanine/Congo red. RESULTS: Data confirm the excellent behaviour of bovine bone and of TiO blasted fixtures. The experimental results bring into evidence that, in cases of Guided Bone Regeneration (GBR) by means of membrane, the use of fixtures with a blasted surface (TiOblast), and of Bio-Oss as bone substitute, made osseointegration easier. CONCLUSIONS: Results, moreover, suggest that in case of implant surgery with GBR, in order to allow the maturation of regenerated bone, it's healing time must be prolonged.

Animals↗
PubMed1998

[Mycoplasma pneumoniae pulmonitis: delayed diagnosis and empirical therapy].

UNLABELLED: MYCOPLASMA PNEUMONIAE: Delayed diagnosis and empiric therapy. BACKGROUND: To evaluate the consistency of IHA test to the initial diagnosis and therapy in suspected cases of Mycoplasma pneumoniae pneumonia (MP). METHODS DESIGN: retrospective-descriptive. ENVIRONMENT: Division of Pneumology, IRCCS Policlinico S. Matteo, Pavia from November 1991 to October 1993. PATIENTS: 235 pts inpatients. VARIABLES: age, sex, clinical diagnosis, microbiology, serological investigations for MP by indirect hemagglutination test (IHA); therapy, monitoring and evaluation; considered as positive IHA titres > or = 1:40. RESULTS: Clinical presentation not different from other "atypical" pneumonia. Macrolides, aminoglycosides, quinolones or cephalosporins were the usual treatment; patients recovered within 1 to 2 weeks consistently to the severity of disease. Sixty-five cases were IHA-positive (28%). Serological outcomes were usually known after 7 to 10 days or more, when most of patients resulted discharged. Mean age in IHA-positive pts was younger than in IHA-negative (31.3 vs 51.6 yrs; p < 0.0001). IHA test was repeated after 3 weeks in 23/235: 2 (9%) remained negative and 15 (65%) positive; 5 (22%) turned from positive to negative; 1 (4%) from negative to positive. CONCLUSIONS: Clinical and roentgenological presentation similar to other "atypical" pneumonia; late etiological diagnosis and only in 28%, including those monitored distally; significantly young age among IHA-positives; empiric therapy, effective even on the remaining 72% IHA-negative. IHA, commonly used test with good specificity and sensitivity, is of late support to the clinician in short course and uncomplicated disease.

Adolescent↗
PubMed1997

Damage of foldable intraocular lenses by incorrect folder forceps.

PURPOSE: To evaluate possible damage of foldable silicone or acrylic intraocular lenses caused by the use of incorrect lens folder forceps. METHODS: Ten silicone and 10 acrylic intraocular lenses were divided into two groups, each containing five silicone and five acrylic lenses. Two easily mistaken folder forceps, each expressly designed for either silicone or acrylic lenses only were properly used to fold the intraocular lenses in group 1 whereas in group 2, the silicone lenses were folded with the forceps designed for the acrylic lenses, and the acrylic lenses were folded with the forceps designed for the silicone lenses. We observed the lenses by transmission and scanning microscopy after folding. RESULT: The acrylic lenses folded with forceps designed for the silicone lenses (group 2) disclosed considerable damage of the lens optic. CONCLUSION: Incorrect folder forceps may damage acrylic intraocular lenses.

Acrylates↗
PubMed1997

Cytokine patterns in adults with AIDS.

BACKGROUND: It has been reported that in HIV infected patients enhanced production of IL-4 and IL-10 in response to stimulation of peripheral blood lymphocytes with phytohemagglutinin is associated with disease progression. Some have proposed that a switch from a cytokine profile associated with CD4+ Th1 predominance (IL-2, IFN-G, TNF-B) to Th2 predominance (IL-4, IL-5) plays a major role in the progression of HIV infection. Others find no clear evidence for the dichotomy of Th1 and Th2 predominance in HIV infected patients Discrepant results have been reported in studied populations in which only a few cytokines have been examined. METHODS: Thirty-one adult patients with AIDS but without other active infections provided serum and peripheral blood lymphocytes for determination of cytokine levels. Their responses were compared to those of five normal healthy volunteers without active infection. ELISA techniques were employed to quantitate cytokine levels. Both circulating lymphocyte and enriched lymphocyte populations were studied with and without stimulation employing phytohemagglutinin and/or rhIL-2. RESULTS: Patterns of cytokine expression were analyzed in 31 adult patients with AIDS but without other active infections. All had CD4+ cell counts below 50 and large viral loads (Roche PCR). The unstimulated cytokine profile in these patients generally showed marked elevations in IL-1, IL-3, IL-4, IFN-G, TNF-A, TNF-B, OSM, and TGF-B. Minimal elevations compared to normal healthy volunteers were noted for IL-2, IL-6, IL-8, IL-12, IFN-A, and IL-6SR. The levels of RANTES were lower than in normal healthy volunteers. Responses of peripheral blood lymphocytes to stimulation with phytohemagglutinin showed enhancement of all cytokines in all subjects studied though the response was much less marked in AIDS patients than in normal volunteers with the exception of IL-3, IL-4, IL-8, TNF-B, and TGF-B which are increased. Little difference in IL-2 and IL-12 expression was noted between stimulated peripheral blood lymphocytes of AIDS patients and normal healthy volunteers. No relation was noted with patient age or with any use of antiretroviral agents. Recombinant human IL-2 was a less potent stimulant than was phytohemagglutinin. CONCLUSION: The character of cytokine response in AIDS patients may be directly related to the stimulus employed in test systems. There is no evidence for Th1/Th2 dysregulation. Cytokine elevations in AIDS patients generally are reflective of chronic infection (the virus). Lymphocytes from AIDS patients do not respond as well to stimulation as do those from normal healthy volunteers. The stimulated lymphocyte response in AIDS patients suggests there is underlying low-grade host versus virus reaction in these patients (exaggerated responses of IL-3, IL-4, IL-8, TGF-B).

Acquired Immunodeficiency Syndrome↗
PubMed1997

Blood pressure peaks correlated with plasma fibronectin levels and microalbuminuria in hypertensive pregnancies.

A group of 32 selected hypertensive pregnant women under antihypertensive therapy, with biochemical parameters, functional parameters, plasma fibronectin levels (PLF), microalbuminuria (MA) levels and continuous 24 h blood pressure monitoring, were followed monthly until delivery and during puerperium. Also possible biochemical and clinical markers and the predictive value in the complications during PIH were attempted to be identified. There was a statistical correlation between systolic pressure peaks associated with high levels of PLF and MA in hypertensive pregnant women who may have a higher risk of pregnancy or cardiovascular complications. Continuous 24 h blood pressure monitoring in hypertensive pregnancies was found to be helpful in identifying the highest risk patients especially by reading the night peak percentages.

Adolescent↗
PubMed1997

[Role of transesophageal echocardiography in the diagnosis of obstructive hypertrophic myocardiopathy. Report of 2 cases and review of the literature].

Two cases of obstructive hypertrophic cardiomyopathy, in which the transthoracic echocardiography was not enough to reach the right diagnosis, are reported. The transesophageal echocardiography revealed to be the most useful technique to reach the exact diagnosis and more information about the mechanism of the left ventricular outflow tract obstruction. Moreover, this technique could be useful to direct to a surgical treatment and to monitorize the mitral valve function and the possible complications during operation.

Adult↗
PubMed1997

[Osteo-conductive materials: animal experiments and instrumental analysis II].

BACKGROUND: In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft to fill bone defects, bone substitutes can be useful for bone regeneration. MATERIALS AND METHODS: After a preliminary microscopic examination of histologic samples obtained from semithin sections of the tibias of rats showing no major differences in the results both for the single material and implant time, further studies on five different osteoconductive materials used in oral clinical practice were carried out with microradiography, SEM and X-ray microanalysis. In experimental animals (rats) bone defects 3 mm large were surgically induced in both tibias: one of the defects was filled by bone substitutes and on the other side the bone defect healed naturally. RESULTS AND CONCLUSIONS: The findings obtained were studied in depth, and allowed to conclude that the materials tested are suitable for the purpose for which they are marketed. Non-demineralized bovine bone showed the best results with a high degree of osteointegration. However, the results also show that not all the materials tested offer healing advantages over controls.

Animals↗
PubMed1996

Retinoids irreversibly inhibit in vitro growth of Epstein-Barr virus-immortalized B lymphocytes.

Natural and synthetic retinoids have proved to be effective in the treatment and prevention of various human cancers. In the present study, we investigated the effect of retinoids on Epstein-Barr virus (EBV)-infected lymphoblastoid cell lines (LCLs), since these cells closely resemble those that give rise to EBV-related lymphoproliferative disorders in the immunosuppressed host. All six compounds tested inhibited LCL proliferation with no significant direct cytotoxicity, but 9-cis-retinoic acid (RA), 13-cis-RA, and all-trans-RA (ATRA) were markedly more efficacious than Ro40-8757, Ro13-6298, and etretinate. The antiproliferative action of the three most effective compounds was confirmed in a large panel of LCLs, thus appearing as a generalized phenomenon in these cells. LCL growth was irreversibly inhibited even after 2 days of treatment at drug concentrations corresponding to therapeutically achievable plasma levels. Retinoid-treated cells showed a marked downregulation of CD71 and a decreased S-phase compartment with a parallel accumulation in Gzero/ G1 phases. These cell cycle perturbations were associated with the upregulation of p27 Kip1, a nuclear protein that controls entrance and progression through the cell cycle by inhibiting several cyclin/cyclin-dependent kinase complexes. Unlike what is observed in other systems, the antiproliferative effect exerted by retinoids on LCLs was not due to the acquisition of a terminally differentiated status. In fact, retinoid-induced modifications of cell morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and increased expression of CD38 and c-Ig), and IgM production were late events, highly heterogeneous, and often slightly relevant, being therefore only partially indicative of a drug-related differentiative process. Moreover, EBV-encoded EBV nuclear antigen-2 and latent membrane protein-1 proteins were inconstantly downregulated by retinoids, indicating that their growth-inhibitory effect is not mediated by a direct modulation of viral latent antigen expression. The strong antiproliferative activity exerted by retinoids in our experimental model indicates that these compounds may represent a useful tool in the medical management of EBV-related lymphoproliferative disorders of immunosuppressed patients.

Antigens, CD↗
PubMed1996

[Abnormal vasomotor response of the forearm due to propranolol-induced loss of cardiopulmonary baroreflex sensitivity: experience with seven cases of recent myocardial infarct].

In 7 patients suffering from acute myocardial infarction (AMI) occurring in the previous 30 days, we investigated forearm vascular reactivity to lower body negative pressure (LBNP), by the strain gauge plethysmography with simultaneous administration of negative pressure around the lower limbs. This manoeuvre has then been repeated after 10 days of oral beta-blocker therapy (propanolol 160 mg/die). A significant flow reduction derived from LBNP associated to plethysmography with respect to plethysmography alone, but this significant difference was suppressed by propranolol treatment, that prevented the reflex decrease in forearm blood flow, (forearm blood flow from 5.97 to 3.85 ml/min/100 ml in wash-out vs 5.64 to 5.75 ml/min/100 ml during propranolol treatment). We hypothesize that this phenomenon is due to the desensitizing effect of propranolol on cardiopulmonary mechanoreceptors (CPB), with the consequent loss or reduction of their functional inhibition for the efferent sympathetic outflow towards resistance vessels in skeletal muscle. Therefore, LBNP does not elicit forearm reflex sympathetic vasoconstriction, because pressure unloading of CPB areas is no longer able to modify sympathetic discharge, since the influence on it of baroreceptor activity has already been weakened by prolonged beta-blockade. Thus, the LBNP low levels, by ruling out and/or by removing the CPB activity are theorically able to elicit sympathetic "disinhibition", and to exercise, consequently, a reflex, vasoconstrictor influence upon the forearm vascular bed, whereas the same reflex behaviour by forearm resistance vessels does not appear feasible if the CPB activity has been preventively minimized by prolonged, chronic beta-blockade.

Adrenergic beta-Antagonists↗
PubMed1995

Identification and characterization of an Epstein-Barr virus-specific T-cell response in the pathologic tissue of a patient with Hodgkin's disease.

Several lines of evidence indicate that an impairment of EBV-specific immune responses may contribute to the pathogenesis of Hodgkin's disease (HD). At present, however, it is not clear whether a defective immunity to EBV is a characteristic restricted to EBV-associated HD cases or a more generalized phenomenon, part of the inherent immune deficiency of HD patients. In this study, we have addressed this issue by analyzing EBV-specific responses in infiltrating T lymphocytes (TILs) from one HD biopsy, where the virus was confined to a small proportion of apparently normal lymphocytes. TIL cultures were established using low amounts of recombinant interleukin 2 and in the absence of specific stimulation, conditions that preferentially induce the proliferation of in vivo activated T cells. An EBV-specific cytotoxic component was revealed by the capacity of these TILs to lyse autologous EBV-positive lymphoblastoid cell lines (LCLs) obtained by spontaneous transformation from the lesion but not HLA-mismatched LCLs and autologous phytohemagglutinin blasts. This cytotoxic activity closely resembled that of EBV-specific memory T cells, which may be reactivated from the blood lymphocytes of healthy donors by in vitro stimulation with autologous LCLs. The use of a panel of appropriately HLA-matched B95.8-transformed LCLs as targets in standard 51Cr release assays revealed EBV-specific cytotoxic responses to be restricted mainly through the A11 and B44 HLA alleles with a minor HLA-A26-restricted component. Using autologous fibroblasts infected with recombinant vaccinia viruses expressing the EBV latent antigens, the TIL culture was shown to recognize latent membrane protein 2 and, to a lesser extent, EBV-encoded nuclear antigen 6. In addition, a strong proliferative response was induced by coculture of TILs with autologous but not with allogeneic LCLs or autologous phytohemagglutinin blasts. Six CD4-positive, EBV-specific T-cell clones were isolated by limiting dilution. The study of cytokine mRNA expression, carried out by reverse transcriptase-assisted PCR, revealed that three of these T-cell clones expressed a Th0 phenotype, whereas 1 had a Th2 phenotype. These findings are consistent with the presence in this HD lesion of an ongoing immune response against EBV-carrying cells and suggest that the complex immune deficiency that characterizes HD patients probably does not include a generalized, constitutional defect of EBV-specific T-cell responses.

Adult↗
PubMed1995

IL-3 is produced by normal stroma in long-term bone marrow cultures.

Interleukin-3 (IL-3) has been shown to have significant effects on haemopoiesis in vitro, but early investigations of normal human long-term bone marrow cultures (LTBMC) have failed to demonstrate IL-3 production by stromal cells, either by Northern blotting for mRNA, or assaying for bioactivity in culture supernatants. One recent report, using reverse transcription-polymerase chain reaction (RT-PCR), demonstrated IL-3 expression in only one of eight cultures. We have developed a sensitive bioassay for the detection of IL-3 production from normal stroma in LTBMC. LTBMC were grown until confluent, irradiated, and stroma harvested by trypsinization to yield single-cell suspensions. These cells were then cocultured with target bone marrow mononuclear cells (BMMC), or CD34+ cells in clonogenic assays, either in the presence or absence of anti-IL-3 neutralizing antibodies. We have demonstrated IL-3 production in 32/34 cases. In addition, by separating stroma from target cells using cell culture inserts, we have shown that direct stroma:stem cell contact is not necessary for colony growth, suggesting that IL-3 diffuses into the supernatant. However, when supernatants from LTBMC were assayed by enzyme-linked immunoassay (ELISA), no IL-3 was detected. This suggests that IL-3 is probably produced at low levels and has a short-range interaction. Stroma production of IL-3 was confirmed by the detection by RT-PCR of IL-3 mRNA in 3/3 cases. The simultaneous detection of CD2 mRNA demonstrated that T cells are part of the bone marrow stroma. It is therefore possible and probably likely that these cells are the source of IL-3.

Base Sequence↗
PubMed1994

In vivo phenotypic characteristics of AKR T-cell lymphomas with different leukemic potential: possible role of alpha 4 beta 7 integrin in the progression towards the leukemic phenotype.

The present study was undertaken in order to determine whether the expression of specific surface molecules which mediate immune recognition as well as cell-cell and cell-matrix interactions is associated with the leukemic evolution of T-cell lymphomas. To this end, we have investigated the in vivo phenotypic characteristics and the in vitro natural-killer(NK)-cell susceptibility of a group of MCF-247-induced AKR/J T-cell lymphomas with different leukemic potential. We found that in the AKR/J model, the biological aggressiveness of leukemic cells is not dependent upon an escape from host immune surveillance as a consequence of an in vivo down-regulation of H2-Kk determinants or a resistance to NK lysis. Moreover, NK susceptibility of AKR/J lymphomas does not seem to correlate with the level of H2-antigen expression. No obvious correlation was found between the leukemic phenotype and the amount of MEL-14, LFA-1, ICAM-1, Pgp-1/CD44 and THAM/CD26 antigen expression. An in vivo coordinated up-regulation of alpha 4 and beta 7 integrin chains, with the highest levels of expression detected in secondary sites of leukemic infiltration, was observed in the highly leukemic lymphoma NQ22 and, albeit to a lesser extent, in lymphomas with moderate leukemic potential. Conversely, non-leukemic lymphomas were repeatedly alpha 4- and beta 7-negative. These findings suggest that in the AKR/J system the expression of alpha 4 beta 7 integrin may contribute to leukemic spreading of T-cell lymphomas.

Animals↗
PubMed1993

Per-oral excision of a pharyngeal branchial cyst after MRI study.

A per-oral approach to pharyngeal branchial cysts is possible, and ideal when they are placed medially to the pharyngeal constrictors and no fistular duct is connected to the mass. At present MRI is found to be the best means of achieving the correct diagnosis of morphology and site.

Adult↗
PubMed1992

Pharmacologic properties of Moringa oleifera. 2: Screening for antispasmodic, antiinflammatory and diuretic activity.

Hot water infusions of flowers, leaves, roots, seeds and stalks or bark of Moringa oleifera were screened to detect three pharmacologic activities in experimental models in rats. The antispasmodic activity was demonstrated using isolated duodenum, oral anti-inflammatory activity by carrageenan-induced hindpaw edema and oral diuretic activity by urine output in metabolic cages. The seed infusion showed a significant inhibition of acetylcholine-induced contraction with an ED50 of 65.6 mg/ml bath concentration, inhibition of carrageenan-induced edema at 1000 mg/kg and diuretic activity at 1000 mg/kg. Some activity was also demonstrated in the roots. All doses expressed here are as equivalents of dried starting plant material.

Animals↗