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Biomedical subjects

P Valentini

Publications and source records attributed to P Valentini.

At least 37 records · Page 2Linked to original sources
PubMed1999

The combined use of bioresorbable membranes and xenografts or autografts in the treatment of bone defects around implants. A study in beagle dogs.

The aim of the present investigation was to test the effect of a bioresorbable membrane supported by xenografts or autografts in regenerating bone into peri-implant defects. In 3 dogs, the mandibular premolars P2, P3, P4 and M1 were extracted bilaterally. After 4 months of healing, 3 standardized bone defects were prepared on each side of the mandible and 1 implant per defect was placed. The 6 sites in each dog were distributed into 4 different treatment groups: 2 sites received a Bio-Gide membrane alone (BG); 2 sites received a Bio-Gide membrane supported by Bio-Oss (BG + BO); 1 site received the Bio-Gide membrane supported by autogenic bone harvested from the prepared defects (BG + Aut); 1 site received neither membrane nor bone graft and served as control (C). The soft tissue flaps were adapted and sutured for primary healing. No adverse events occurred during the experimental period. After 16 weeks, the dogs were sacrificed and histomorphometric examinations on non-decalcified ground sections were carried out. The vertical bone growth amounted to 45% (SD +/- 13%) of the defect height in the BG group, to 78% (SD +/- 29%) in the BG + BO group, to 69% (SD +/- 9%) in the BG + Aut group, and to 22% (SD +/- 10%) in C group. The horizontal bone growth measured 78% (SD +/- 16%) in the BG group, 81% (SD +/- 21%) in the BG + BO group, 82% (SD +/- 12%) in the BG + Aut group, and 46% (SD +/- 21%) in the C group. The vertical height of bone growth in contact with the implant measured 17% (SD +/- 12%) in the BG group, 20% (SD +/- 12%) in the BG + BO group, 17% (SD +/- 7%) in the BG + Aut group, and 12% (SD +/- 8%) in the C group. The surface fraction of the graft in direct bone contact measured 89% (SD +/- 9%) in the BG + BO group and 93% (SD +/- 3%) in the BG + Aut group. It is concluded that the bioresorbable membrane tested enhances bone regeneration, in particular in conjunction with the use of a supporting graft material. In addition, deproteinized bovine bone mineral and autogenic bone grafts appeared to be equally well integrated into regenerating bone. Finally, no additional effects in the bone growth was observed with the autogenous bone in comparison with the hydroxyapatite.

Absorbable Implants↗
PubMed1999

Blood pressure-independent cardiac hypertrophy in acromegalic patients.

OBJECTIVE: Acromegaly is frequently associated with an increase in left ventricular mass, even in the absence of systemic hypertension. Pathological studies on acromegalic hearts have shown an extensive interstitial fibrosis, suggesting the existence of a specific acromegalic cardiomyopathy. The aim of this study was to assess left ventricular wall structure in acromegaly by ultrasonic tissue characterization. DESIGN AND METHODS: We studied 10 untreated acromegalic patients and 10 age-matched healthy control subjects. The echo patterns of two-dimensional long-axis end-diastolic echocardiograms were assessed by colour-scale analysis of the interventricular septum, with estimates of the mean colour scale value, the broad band (Bb) and the derived collagen volume fraction (dCVF). We also measured electrocardiographic QT interval dispersion (QTd) as a marker of dyshomogeneous ventricular repolarization. RESULTS: Seven patients had left ventricular hypertrophy according to the sex-independent criteria; of these, two had arterial hypertension. None of our patients had echocardiographic evidence of diastolic or systolic dysfunction. All patients showed significantly increased myocardial echoreflectivity (Bb = 106.4+/-12.1 versus 79.3+/-6.5; dCVF% = 2.78+/-0.53 versus 1.58+/-0.29; P < 0.0001) and QTd (66+/-13 ms versus 54+/-8 ms, P < 0.05). A significant correlation was found between dCVF and the duration of acromegaly (r = 0.80; P = 0.005). CONCLUSIONS: Left ventricular remodelling observed in acromegaly is not related to the presence of arterial hypertension; we hypothesize that the increased echoreflectivity and QTd are long-term consequences of cardiac hypertrophy and prolonged exposure to high levels of growth hormone and insulin-like growth factor-I.

Acromegaly↗
PubMed1998

Histological evaluation of Bio-Oss in a 2-stage sinus floor elevation and implantation procedure. A human case report.

Deproteinized cancellous bovine bone (Bio-Oss) was placed as a grafting material for sinus floor elevation in the right posterior maxilla. After 6 months of healing, 3 cylindrical titanium-plasma coated implants were inserted. Six months later at the abutment connection, it was realized that 1 of the implants could not be reconstructed due to unfavorable positioning. This implant was removed along with a small portion of the surrounding peri-implant tissues. The specimen was processed according to standard techniques for hard tissue histology. In both the grafted area and the previously existing area of the sinus floor the bone was primarily of lamellar structure. Intimate contact between newly formed bone and the particles of the graft was present. No overt signs of resorption of the graft particles were visible. Histomorphometric analysis revealed 63% of implant-bone contact in the zone of pre-existing bone, and 73% in the grafted zone. The area density of bone amounted to 27% in the non-grafted as compared to 28% in the grafted area. In conclusion, this case report documented that deproteinized bovine bone, when used as a grafting material for augmentation of the sinus floor, may lead to proper osseointegration of a dental implant.

Animals↗
PubMed1998

Acute hydrocephalus as a consequence of mumps meningoencephalitis.

Aqueductal stenosis can result from mumps meningoencephalitis. We report a case of acute hydrocephalus from an aqueductal stenosis developed immediately after a clinically evident mumps infection. The patient, aged two years, was treated with an antiedema therapy, and a ventriculoperitoneal shunt was placed. His clinical conditions rapidly improved. Only mumps virus was found in his cerebrospinal fluid culture. This case probably represents the earliest hydrocephalus from mumps, among those reported in the literature.

Acute Disease↗
PubMed1998

An improved method for coronary sinus blood flow monitoring by intravascular Doppler technique.

In order to obtain accurate measurements of coronary sinus blood flow (CSBF), a new catheter (7 French) with a radiopaque, flexible, and basket-shaped tip was developed for guiding a standard 3 Fr Doppler catheter in the coronary sinus (CS) in man. The radiopaque "basket" tip of the catheter allows the operator to stabilize the position of the Doppler transducer in the center of the CS and to accurately measure the CS internal diameter radiologically. CSBF was calculated as the product of CS cross-sectional area by mean CSBF velocity. Doppler-derived CSBF values at rest and during handgrip were compared with those obtained by the local thermodilution technique in 16 patients undergoing diagnostic coronary angiography. During handgrip, mean CSBF increased from 154+/-23 (rest) to 299+/-34 mL/min by the Doppler method and from 148+/-22 to 288+/-32 mL/min by the thermodilution technique. A good correlation (r = 0.86) between the CSBF values with the two techniques was observed. The authors conclude that the intravascular Doppler technique associated with the use of the basket guide catheter provides an accurate and simple tool for monitoring CSBF in patients.

Blood Flow Velocity↗
PubMed1998

Inactivation of Salmonella during microwave cooking.

Sixty meat loaves were experimentally infected with a strain of Salmonella serovar mbandaka to give approximately 10(7) cells/g. Thirty contaminated loaves were cooked in a microwave oven for 4 min, and 30 other samples for 3 min 30 s, both followed by a standing time of 2 min. No viable experimental contaminants were recovered from both core and surface samples of the 30 loaves cooked for 4 min. Loaves cooked for the short time were often Salmonella positive. These results point out that infection hazard linked to microwave cooked food can be avoided by following adequate procedures concerning exposure time, temperature and post-heating holding time. A standardization of microwave ovens for domestic use is desirable, making it easier to give users correct instructions based on careful and strict experimentations approved by Public Health Authorities.

Animals↗
PubMed1997

Serum autoantibodies in chronic hepatitis C: comparison with autoimmune hepatitis and impact on the disease profile.

Antibodies to nuclei (ANA), smooth muscle (SMA), and liver/kidney microsomes type 1 (anti-LKM1) may occur in chronic hepatitis C. Distinct subspecificities, including ANA with the homogeneous pattern (ANA-H) and SMA with antiactin specificity (SMA-AA), are found in autoimmune hepatitis (AIH). This study was performed to characterize the hepatitis C virus (HCV)-associated autoantibodies and to evaluate their influence on the profile of the disease. Two hundred ninety consecutive patients with chronic hepatitis C and 35 control cases with AIH were screened for autoantibodies by indirect immunofluorescence (IFL) at 1:40 serum dilution. The ANA pattern was defined by IFL on HEp-2 cells and the SMA-AA identified by the presence of at least two of the following elements: 1) SMA(T) or SMA(G) pattern by IFL on kidney sections; 2) XR1 precipitating system by counterimmunoelectrophoresis; or 3) typical pattern by IFL on liver sections from phalloidin-intoxicated rats. ANA, SMA, and anti-LKM1 occurred in 9%, 20%, and 6% of chronic hepatitis C cases, respectively. The overall prevalence of autoantibodies was 30% (87 of 290). Compared with AIH, HCV-associated ANA and SMA exhibited ANA-H and SMA-AA at a lower prevalence (38% vs. 71%, P = .04 and 8% vs. 87%, P < .000001, respectively) and had a lower median titer (1:80 vs. 1:320, P < .001 and 1:40 vs. 1:320, P < .000001, respectively). The concomitant positivity for ANA-H and SMA-AA was detected in none of the HCV cases, but in 46% of AIH sera (P < .000001). Two parameters were independently associated with the autoantibodies in chronic hepatitis C: high alanine transaminase (ALT) serum levels (F = 14.04) and female gender (F = 5.03). At the univariate analysis, patients with autoantibodies had a more severe portal-periportal necroinflammation (median Scheuer's score: 2.05 vs. 1.64, P = .003). The presence of autoantibodies did not influence the response to interferon (IFN). In chronic hepatitis C, serum autoantibodies are common, but their subspecificities are distinct from those occurring in AIH. Whereas the absence of ANA-H and/or SMA-AA does not exclude AIH, the characterization of ANA and SMA may help to discriminate between the two conditions. As compared with the seronegative counterpart, autoantibody-positive chronic hepatitis C is more common in females and exhibits a more severe biochemical and histological activity. The response to IFN therapy, however, is similar.

Analysis of Variance↗
PubMed1997

Ultrasound-detected abdominal lymphadenopathy in chronic hepatitis C: high frequency and relationship with viremia.

BACKGROUND/AIMS: This study aimed to investigate the prevalence and significance of ultrasound-detected deep abdominal lymphadenopathy in chronic hepatitis due to C virus. METHODS: One hundred and thirty-four consecutive patients with various liver disorders were examined with portable real-time equipment. RESULTS: In 25 (19%), the procedure failed because of excessive meteorism. Deep nodes, mainly located in the hepato-duodenal ligament, were detected in 62 of the remaining 109 patients (57%), reaching the highest prevalences in primary biliary cirrhosis (5/7, 71%), chronic hepatitis C (44/66, 67%) and autoimmune hepatitis type 1 (2/3, 67%). For all patients, including those with liver diseases with multiple etiology, lymphadenopathy was more frequent in anti-HCV positive (51/81, 63%) than in negative cases (11/28, 39% p=0.02). In chronic hepatitis C, serum HCV RNA was detected by nested polymerase chain reaction in all 31 patients with, but in only 75% (12/16) of those without nodes (p=0.018). No other distinct clinical or laboratory feature was found in association with lymphadenopathy; in particular, its incidence was similar in cases with and without liver cirrhosis. CONCLUSIONS: Enlarged deep abdominal lymph nodes are frequently detected by ultrasound in patients with chronic hepatitis C. This feature may be of diagnostic utility, especially in early cases, when liver cirrhosis has not yet developed and therefore no other ultrasound sign of the underlying disease can be detected. Lymphadenopathy may be of biological significance, marking hepatitis C virus infection in a replicative, viremic stage. These observations support the existence of a close interaction between hepatitis C virus and the lymphatic system.

Abdomen↗
PubMed1997

Antinuclear antibodies and patterns of nuclear immunofluorescence in type 1 autoimmune hepatitis.

To determine the significance of antinuclear antibodies and their patterns of indirect immunofluorescence in type 1 autoimmune hepatitis, sera from 99 patients were evaluated. Patients with antinuclear antibodies had a lower frequency of liver transplantation (6% vs 22%, P = 0.04) than seronegative patients. They were also more commonly HLA-DR4-positive than seronegative patients (56% vs 30%, P = 0.05) and normal subjects (56% vs 30%, P = 0.004). The 42 patients with antinuclear antibodies and a diffuse pattern of indirect immunofluorescence had higher serum titers of ANA (serum titers > or = 1:500, 71% vs 14%, P < 0.0001) and SMA (serum titers > or = 1:500, 69% vs 27%, P = 0.003) than the 22 patients with antinuclear antibodies and a speckled pattern. These patients, however, were otherwise not distinguished by clinical features and treatment response. Patients with a speckled pattern had A1-B8-DR3 more frequently than patients with a diffuse pattern (65% vs 23%, P = 0.005) and normal subjects (65% vs 13%, P < 0.0001), but they had no other salient features. We conclude that patients with antinuclear antibodies have a better long-term prognosis than seronegative patients, and they have HLA-DR4 more commonly. The patterns of indirect immunofluorescence associated with ANA positivity have no practical clinical implications.

Adult↗
PubMed1997

Factors affecting the therapeutic choice in patients with multivessel coronary artery disease. The Studio Lombardo Angiografia Multivasali (SLAM) Study Group.

OBJECTIVE: To assess how clinical and angiographic findings are related to the decision to carry out coronary angioplasty (PTCA) or coronary bypass grafting in patients with multivessel coronary artery disease. DESIGN: Prospective survey carried out in 14 centres in the Lombardia region of Italy. PATIENTS: 1468 consecutive patients under going coronary arteriography for known or suspected ischaemic heart disease between May and October 1994, who were found to have multivessel coronary artery disease. MAIN OUTCOME MEASURES: Multivariate analysis was undertaken using stepwise logistic regression to identify the clinical and angiographic variables correlated with revascularisation (v medical treatment) in all of patients, and with surgery (v angioplasty) in the subset of revascularised patients. RESULTS: In all patients the clinical decision after coronary arteriography was made by physicians of each participating centre on the basis of their experience and clinical judgment: 53% of patients had bypass surgery, 28% had PTCA, and 19% continued medical treatment. The choice of a revascularisation procedure was directly related to a clinical diagnosis of unstable angina (P < < 0.001), the presence of left anterior descending artery disease (P < < 0.001), and to an ejection fraction > or = 40% (P < < 0.001), and inversely related to history of previous coronary bypass surgery (P < < 0.001). In revascularised patients, bypass surgery was the preferred treatment in patients with left anterior descending artery disease (P < < 0.001), three-vessel disease (P < < 0.001), and in those with at least one occluded vessel (P = 0.008). The choice of PTCA was significantly related to history of previous PTCA (P < < 0.001) or coronary bypass surgery (P < < 0.001), to a clinical diagnosis of non-Q wave myocardial infarction (P = 0.002), and to the possibility of implanting an intracoronary stent (P = 0.01). CONCLUSIONS: Bypass surgery is still the most widely used treatment for patients with multivessel coronary artery disease. This analysis provides a basis for comparison with future developments in the treatment of such patients. Further advancements in PTCA technology are needed to tilt the balance in favour of this less invasive procedure.

Adult↗
PubMed1997

Maxillary sinus floor elevation for implant placement with demineralized freeze-dried bone and bovine bone (Bio-Oss): a clinical study of 20 patients.

The objective of this study was to determine the predictability of endosseous implants placed in a maxillary sinus grafted with a mixture of bovine porous bone mineral and demineralized freeze-dried bone. Sixty implants were placed in 20 patients representing 28 sinuses using either a one- or two-stage technique. After an implant loading period of more than 2 years, the survival rate (eg, a clinically functioning implant without signs of mobility or infection) varied from 90% to 96%. No infections or other complications were encountered. The data suggest that this treatment regimen can result in a high rate of survival.

Aged↗
PubMed1996

Expression of neutrophil and monocyte CD11B/CD18 adhesion molecules at different sites of the coronary tree in unstable angina pectoris.

To assess the site of leukocyte activation in unstable angina, the expression of neutrophil and monocyte CD11B/CD18 adhesion molecules in 26 patients was measured from blood samples taken from the coronary ostium, the coronary sinus, and the coronary artery just distal to the culprit lesion (postobstructive chamber). CD11B/CD18 adhesion molecules detected by direct immunofluorescence evaluated by flow cytometry were significantly higher in the coronary sinus blood than in both the coronary ostium and the postobstructive chamber blood, suggesting that leukocyte activation takes place at the microcirculatory interface with the injured myocardium, probably as the result of short but repeated episodes of myocardial ischemia.

Adult↗
PubMed1996

Correlation between clinical and morphologic findings in unstable angina.

This study was undertaken to verify the hypothesis that the discrepant findings in published reports on the prevalence of thrombus in unstable angina depend on the inclusion of different clinical subsets in the various studies. We therefore correlated the clinical characteristics of patients included under the label of unstable angina with the morphologic features assessed by coronary angiography and intravascular ultrasound, and with histopathologic findings of atherectomy specimens. Fifty-eight patients with unstable angina (class B of the Braunwald classification) undergoing coronary arteriography followed by either coronary angioplasty (n = 20) or directional coronary atherectomy (n = 38) were studied. Fifteen patients were in class IB and 43 were in class II to IIIB. Among these 43 patients with angina at rest, 28 had ST-segment elevation during pain, and 15 had ST-segment depression, and 26 developed negative T waves on the baseline electrocardiogram (ECG) as a result of prolonged or repeated episodes of resting chest pain. Intravascular ultrasound examination of the culprit lesion was performed in 43 patients before the interventional procedure, and histopathologic analysis of atherectomy specimens was performed in 38 patients. Complex lesion morphology by angiography was observed in 31 patients (53%) without any significant relation to various clinical subsets. Patients in Braunwald class IB had more calcific plaques than patients in class II to IIIB (p < 0.001). Among patients with angina at rest, those with negative T waves on the baseline ECG, as well as those with transient ST elevation during pain, had a significantly higher incidence of noncalcific lesions (p = 0.001 for both). Analysis of atherectomy specimens revealed acute coronary lesions (thrombus and/or intraplaque hemorrhage) in 18 patients (47%). The incidence of acute coronary lesions was significantly higher in patients with than without negative T waves on the baseline ECG (p = 0.005), and increased further when negative T waves were combined with ST elevation during pain (p = 0.001). Multivariate analysis revealed that the presence orf negative T waves on the baseline ECG was the only explanatory variable related to the presence of acute coronary lesions by histology (p = 0.03). Patient subsets included in the broad spectrum of unstable angina have different morphologic features and incidence of acute coronary lesions by histology. These data provide an explanation for the discrepant findings in published reports on the relevance of thrombus formation in the pathogenesis of unstable angina.

Angina, Unstable↗
PubMed1996

Frequency and significance of antibodies to actin in type 1 autoimmune hepatitis.

Antibodies to actin have been proposed as diagnostic markers for type 1 autoimmune hepatitis. Our aims were to determine 1) if testing for antibodies to actin is superior to testing for smooth muscle antibodies (SMA); 2) if these antibodies identify patients with distinctive clinical features; and 3) if the production of antibodies to actin is associated with genetic risk factors for autoimmune hepatitis. Sera from 99 patients with type 1 autoimmune hepatitis were tested. The frequencies of HLA B8, DR3, DR4, and A1-B8-DR3 in patient subsets were compared with those in 80 normal subjects. Seventy-three patients (74%) had antibodies to actin. Antibodies to actin were found more commonly in patients with SMA than in patients without them (86% vs. 7%, P < .0001). Screening only for antibodies to actin and antinuclear antibodies (ANA) failed to establish the diagnosis of autoimmune hepatitis in 5 patients. Patients with antibodies to actin were younger than seronegative patients. They were also more commonly DR3-positive than normal subjects and more frequently B8-positive than patients with non-actin-associated SMA (49% vs. 0%, P = .004). Only patients with antibodies to actin died of liver failure (6% vs. 0%), and 10 of 11 patients requiring liver transplantation were seropositive for these antibodies. Indeed, death and liver transplantation occurred more frequently in these patients than in actin-negative patients with ANA (19% vs. 0%, P = .03). We conclude that routine screening for antibodies to actin may miss patients with type 1 autoimmune hepatitis. Antibodies to actin are associated with HLA B8 and DR3, and they identify patients with a poor prognosis.

Actins↗
PubMed1996

Down regulation of NM23.H1, NM23.H2 and c-myc genes during differentiation induced by 1,25 dihydroxyvitamin D3.

The NM23 gene, involved in the negative regulation of metastatic progression, has been found to be highly homologous to developmentally regulated genes such as the awd gene in Drosophila melanogaster and the Gip17 gene in Dyctiostelium discoideum. To ascertain whether the NM23 genes are involved in the differentiation processes of human cell lines, the NM23.H1 and NM23.H2 expression level has been determined during the monocyte-macrophage differentiation of HL-60 and U-937 cell lines induced by vitamin D3. In both lines, vitamin D3 produced induction of differentiative markers, inhibition of cell proliferation and a decrease of the NM23.H1, NM23.H2 and c-myc genes, behaving both as a differentiative and an antiproliferative agent. The fact that the c-myc transcriptional factor PuF is identical to the NM23.H2 gene and that NM23 protein could be a transcriptional factor suggests that the regulatory action exerted by vitamin D3 on c-myc transcription is mediated by NM23.H2.

Blotting, Northern↗
PubMed1996

In vivo biological response following low-dose interleukin-2 in complete remission B-cell non-Hodgkin's lymphoma patients. Italian Lymphoma Study Group (GISL).

The aim of the present study is to verify whether recombinant interleukin-2 (rIL-2) at low doses is well tolerated in aggressive lymphoma in complete remission (CR), and if there may be a biological justification for its use as a remission-maintenance therapy able to reduce the percentage of relapses. We treated 6 patients with B-cell non-Hodgkin's lymphoma (B-NHL) in CR following PM-Cytabom with rIL-2 3 IMU s.c. x 5 d per wk, every other wk for 8 wk. Our results show that this treatment provokes statistically significant changes in the absolute number of lymphocytes, eosinophils, CD25+ and CD122+ cells and soluble IL-2 receptors; these doses, however, are not sufficient to modify CD3+, CD16+ and CD56+ cell values or natural killer and lymphokine activated killer cell activity. Thus these findings do not appear to constitute a biological rationale for the use of rIL-2 at this dose and schedule as a remission-maintenance therapy in B-cell NHL. Nevertheless, the results are a valid basis for further study of the use of the same rIL-2 doses for a longer period of time in combination with other cytokines, in the hope that the biological effects can be augmented without increasing the toxic side effects.

Cytokines↗
PubMed1996

[Haemophilus influenzae disease in childhood. Comment about case reports of meningitis].

The authors describe a series of Haemophilus influenzae meningitis in childhood, obtained with a retrospective analysis of the cases of bacterial meningitis admitted to Isolamento Pediatrico department of "A. Gemelli" Polyclinic in Rome, from January 1, 1970 to December 31, 1994. Haemophilus influenzae resulted the second agent in frequency (first was Neisseria meningitidis). Main features were: no patient was older than 5 years, and most of them were less than 2 years old; clinical feature was aspecific in the first year of life, it was typical of bacterial meningitis in older children; blood culture and detection of bacterial antigens in cerebrospinal fluid (CSF) were useful for etiological diagnosis, supporting CSF culture; clinical course was characterized by many complications, but no case was lethal and incidence of sequelae at discharge was low; C reactive protein was effective as index of inflammation and as indicator of arising complications; chosen antibiotics were efficacious, but frequency of antibiotic resistance, especially to beta-lactams, was found to be increasing; results of dexamethasone therapy were not of univocal interpretation. The authors are in favour of spreading of vaccination against Haemophilus influenzae in Italy, too, in order to eradicate this disease, as experiences in other countries are successful, and of setting up of the combined vaccines, in order to increase parents' compliance to vaccinal practices.

Child, Preschool↗