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Biomedical subjects

A Santini

Publications and source records attributed to A Santini.

At least 37 records · Page 2Linked to original sources
PubMed1998

Microleakage of composite restorations bonded with three new dentin bonding agents.

This report evaluates the impact of two dentin bonding techniques on microleakage of Class V restorations bonded with three new dentin bonding systems. Forty-eight extracted human premolar and molar teeth were randomly assigned to four groups for bonding with EBS Bonding System (ESPE, Seefeld, Germany); Syntac Single-Component (Ivoclar-Vivadent, Schaan, Liechtenstein); Scotchbond 1 (3M Dental Products, St. Paul, Minnesota); and a control, Prime and Bond 2.1 (Dentsply, DeTrey, Konstanz, Germany). Cavities were cut in both the buccal and lingual surfaces. The coronal half of each preparation was in enamel, and the gingival half was in cementum or dentin. The cavities were restored with composite after the application of dentin bonding agents, using two different drying techniques for each material. The teeth were stored in distilled water for 6 days at 37 degrees C and then thermocycled. The restorations were examined microscopically for leakage, using Procion brilliant red as a marker. All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was no significant difference between any of the experimental materials and the control for either wet bonding (Kruskal-Wallis: p = .8920) or dry bonding (Kruskal-Wallis: p .9973); or between the two techniques for each material (Mann-Whitney U in all cases p > .05). Scanning electron microscopic examination confirmed that the zones of microleakage, as indicated by dye penetration, were principally resincohesive failures within the collagen-rich hybrid layer. Three water-based bonding agents were unable to prevent microleakage at either the enamel or dentin margins of Class V cavities regardless of which bonding technique was employed. All systems behaved equally.

Analysis of Variance↗
PubMed1998

A scanning electron microscopic study of the effect of Gluma CPS bonding system on dentinal smear layers produced by different bur types and rotational speeds and on the resin-dentin interface.

OBJECTIVE: The purpose of this study was to investigate the effect of conditioners on smear layers produced by different bur types and rotational speeds and to study the interaction of subsequently applied primer and sealer with these conditioned surfaces. METHOD AND MATERIALS: Smear layers were produced on human teeth immediately after extraction by burs rotating at approximately 6,000 rpm without water spray and 400,000 rpm with water spray. Gluma CPS etchant was applied for 15, 30, and 60 seconds, and a 20% phosphoric acid liquid (control) was applied for 30 seconds to smear layers. The specimens were prepared by critical point drying for scanning electron microscopic imaging within 24 hours. Additional specimens were prepared and treated with Gluma CPS primer and sealer, according to the manufacturer's instructions. RESULTS: There were only small variations in the smear layer thicknesses with different bur types or speeds of rotation. Gluma CPS conditioner, applied for the recommended times, did not completely remove the smear layer. An altered smear layer, composed of a reaction product, remained on the dentinal surface. A zone of demineralization did occur, however, beneath the partially removed smear layer in both the 15- and 30-second specimens but was only partly filled by primer and sealer. Smear layers were completely removed by the 20% phosphoric acid liquid to expose a delicate collagen network. CONCLUSION: An understanding of the appropriate treatment for smear layers is crucial to the development of improved dentin bonding systems.

Acid Etching, Dental↗
PubMed1998

Effect of wet and dry bonding techniques on marginal leakage.

PURPOSE: To evaluate the effect of wet and dry bonding on microleakage of Class V restorations bonded with three bonding agents. MATERIALS AND METHODS: 60 extracted human premolars and molars were randomly assigned to three groups for bonding with Gluma CPS, EBS (ESPE) and Prime & Bond 2.1. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The cavities were restored with composite after the application of dentin bonding agents using a wet and dry technique for each material. The teeth were stored in distilled water for 6 days at 37 degrees C, thermocycled, and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. RESULTS: All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was a significant difference between the groups for both wet-bonding (P = 0.039) and dry-bonding (P = 0.024). There was no significant difference between the groups at the enamel margin (wet bonding: P = 0.179, dry-bonding: P = 0.357). The wet-bonding technique was compared with the dry-bonding technique for each material at both the gingival and enamel margins and no significant differences were observed (in all cases P > 0.47). SEM showed that in dye-labeled areas debonding occurred mostly, but not always, near the resin-hybrid interface.

Analysis of Variance↗
PubMed1998

Biocompatibility of dentine-bonding agents. 1. Factors associated with function.

The paper reviews the literature on the biocompatibility of dentine-bonding agents with respect to their ability to perform their defined function. Scanning electron microscope (SEM) pictures, prepared by the critical-point drying technique, are used to illustrate the various aspects of bonding to dentine such as the nature of dentine, the smear layer and the effects of primers, conditioners and etchants. From the review of the literature it can be concluded that the mechanisms of bonding to dentine are still not fully understood. The more recently introduced materials use mechanical means of adhesion where the dentine is altered by primers or conditioners to expose collagen fibres and a hybrid zone is created by the penetration of unfilled resins into this fibrous network. The irritant effects of a bonding agent on pulpal tissue may be caused by bacterial ingrowth due to initial poor bonding or a breakdown of the bond in addition to any inherent toxicity of the constituents of the bonding agent.

Bicuspid↗
PubMed1998

[Rapid resolution of ST-segment elevation predicts functional recovery in acute myocardial infarction treated with primary percutaneous transluminal coronary angioplasty].

OBJECTIVES: This study was designed to prospectively assess the ability of the 12-lead electrocardiogram (ECG) and optimal ECG criteria to predict late functional recovery in patients with acute myocardial infarction (AMI) treated with primary coronary angioplasty (PTCA) BACKGROUND: A simple clinical method to predict clinical outcome in patients with reperfused AMI is highly desirable from a clinical point of view. METHODS: Seventy-five patients with AMI treated with successful PTCA (TIMI flow grade 3 and residual stenosis < 30%) underwent serial 12-lead ECG before PTCA and every hour for the first 6 hours and then at 9, 12, and 18 hours after PTCA. All patients underwent two-dimensional echocardiography before PTCA and 1 and 6 months later for the evaluation of regional wall motion. The ST segment level in the lead exhibiting the maximal ST elevation (ST increase max) and the sum of the ST segment elevation (sigma ST increases) were calculated on initial ECG and a cut-off values of > or = 50% reduction of ST increases max sigma ST increases elevation and sampling intervals were correlated with late functional recovery. A wall motion score index (WMSI: 1 = normal to 4 = dyskinesia) and 16-segment model were used. Reversible dysfunction was defined as a decrease of > or = 0.22 in WMSI. RESULTS: At univariate analysis a > or = 50% reduction of both ST increases max and sigma ST increases was related to late functional recovery. Multiple logistic regression analysis revealed that reduction of sigma ST increases was the most powerful predictor of late functional recovery (p = 0.008). A > or = 50% reduction of sigma ST increase within 4 hours of PTCA provided the optimal criterion for predicting late functional recovery. CONCLUSIONS: Rapid reduction of sigma ST increases elevation is an accurate predictor of left ventricular functional recovery in patients with AMI treated with primary PTCA. Optimal criteria include a reduction in sigma ST increases elevation > or = 50% within 4 hours of PTCA.

Adult↗
PubMed1998

Biocompatibility of dentine-bonding agents. 2. Pulpal considerations.

The paper reviews the literature concerning the biocompatibility of dentine-bonding agents. The literature review indicates that two main hypotheses are presented to explain pulpal inflammation following the placement of materials such as dentine-bonding agents, namely material toxicity and bacterial infection. The paper discusses the role of such factors as microbial microleakage, remaining dentine thickness and the smear layer as factors in determining material toxicity and summarises the reported biocompatibility studies. From this it is concluded that most bonding agents contain constituents which have a potential irritant or toxic effect on the pulpo-dentinal complex. The irritant effect may be due to constituents of the bonding agents, or to poor or lost bonding, or to a combination of all these factors. The recently favoured total-etch technique may cause an increase in dentine permeability by removal of the smear layer and thereby increase the irritant effect of some materials.

Animals↗
PubMed1997

Influence of infarct-zone viability on left ventricular remodeling after acute myocardial infarction.

BACKGROUND: The relation between residual myocardial viability after acute myocardial infarction (AMI) and ventricular remodeling has yet to be fully elucidated. We hypothesized that the presence of residual viability would favorably influence left ventricular remodeling after AMI and that serial changes in left ventricular dimensions might be related to the extent of myocardial viability in the infarct zone. METHODS AND RESULTS: Ninety-three patients with a first AMI successfully treated with primary coronary angioplasty underwent two-dimensional echocardiography within 24 hours of admission and low-dose dobutamine echocardiography at a mean of 3 days after AMI. Two-dimensional echocardiography and coronary angiography were obtained in all patients 1 and 6 months after coronary angioplasty. On the basis of dobutamine echocardiography responses, patients were divided in two subsets: those with (n=48; group I) and those without (n=45; group II) infarct-zone viability. There was no difference in minimal lesion diameter and infarct-related artery patency at 1 and 6 months between the two groups. Group II patients had significantly greater end-diastolic (76+/-18 versus 53+/-14 mL/m2; P<.0003) and end-systolic (42+/-17 versus 22+/-11 mL/m2; P<.0003) volumes at 6 months than did patients in group 1. The extent of infarct-zone viability was significantly inversely correlated with percent changes in end-diastolic volumes at 6 months (r=-.66; P<.000001) and was the most powerful independent predictor of late left ventricular dilation. CONCLUSIONS: After reperfused AMI, the degree of left ventricular dilation, when it occurs, is inversely related to the extent of residual myocardial viability in the infarct zone. Thus, the absence of residual infarct-zone viability discriminates patients who develop progressive left ventricular dilation after reperfused AMI from those who maintain normal left ventricular geometry.

Aged↗
PubMed1997

Bailout coronary stenting without anticoagulation or intravascular ultrasound guidance: acute and six-month angiographic results in a series of 120 consecutive patients.

The purpose of this study was to evaluate the feasibility, safety, and efficacy of bailout coronary stenting without anticoagulation or intravascular ultrasound guidance in patients with acute or unequivocal threatened closure after conventional angioplasty. One hundred twenty consecutive patients were prospectively enrolled according to the following criteria: 1) acute or threatened closure after balloon angioplasty; 2) reference vessel diameter > or = 2.5 mm. All patients after stent implantation were on antiplatelet treatment with aspirin and ticlopidine. Four types of stents were used: Palmaz-Schatz (J&J), Gianturco-Roubin (Cook), Freedom (Global Therapeutics), and Microstent (AVE). Procedural results: a total of 206 stents were implanted in 134 target lesions with a stent deployment success rate of 100%; 44 target lesions were treated with multiple stent implantation; the mean luminal diameter after stenting was 3.14 +/- 0.34 mm, and the mean final percent diameter stenosis was -2 +/- 10%; the mean balloon to vessel ratio was 1.11 +/- 0.15; the mean final pressure inflation was 13.9 +/- 2.4 atm; an optimal angiographic result was achieved in 128 lesions (96%). In-hospital results: in-hospital recurrent ischemia occurred in 4 patients (3%); recurrent ischemia resulted directly in death in 1 patient, in nonfatal Q-waves infarction in 2 patients, and in emergency coronary artery surgery in 1 patient. Six-month clinical follow-up results: event free survival rate was 77%; 1 patient had non fatal infarction; the incidence of repeat revascularization procedures was 19%; there were no cardiac deaths. Angiographic follow-up results (follow-up rate 93%): the restenosis or reocclusion rate was 28%. Bailout coronary stenting without chronic anticoagulation treatment or intravascular ultrasound guidance may be considered a highly feasible and safe treatment for acute or threatened closure after failed angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Abdominal aortic aneurysm: course of morbimortality of elective surgery in 20 years].

Abdominal aortic aneurysms (AAA) usually undergo progressive dilatation and eventually may rupture, complication that carries a high mortality rate. If certain clinical conditions, like operative risk and aortic diameter are met, all patients should be considered for surgical repair. Analysis of our results with the surgical treatment of asymptomatic AAA prompted this study. Out of 479 consecutive patients operated because of AAA between 1976 and 1995, 378 (79%) were electively treated. Two decades: 1976-85 (101 patients) and 1986-95 (277 patients) were compared as far as associated medical conditions, surgical procedures, complications and mortality rate. There was no difference in age, sex, risk factors and aortic diameter. During the second decade we favoured the use of aortic tube grafts (53% vs 25%, p < 0.01) and epidural anesthesia (94% vs 35%, p < 0.01). During the last decade only 53.3% of the patients received blood transfusion, compared to 95.3% during the first period (p < 0.001). Operative mortality decreased from 5.94% to 0.72% (p < 0.05). Postoperative hospital stay diminished from 11.2 +/- 8.2 to 9.6 +/- 6.3 days (p < 0.05). These results compare favourably with those reported from other academic centers and support our therapeutic approach. Our contemporary surgical results serve as a reference for future clinical evaluation of endovascular procedures currently under investigation.

Aged↗
PubMed1996

Synthesis and antinociceptive activity of peptides related to interleukin-1 beta 193-195 Lys-Pro-Thr.

To obtain information about the structure-activity relationships of analgesic peptides, we modified the previously reported tripeptide, H-Lys-Pro-Thr-OH (C). The proline part in C was replaced with various analogues of unconventional amino acids [(3aS, 7aS)-octahydroindole-2-carboxylic acid (Oic), (S,S,S,)-2-azabiciclo [3.3.0]octane-3-carboxylic acid (Aoc), D-Aoc, and (2S, 4R)-hydroxyproline (Hyp)] with varying lipophilic, steric, and conformational properties, and alternatively with Lys and Orn in the lysine part. Moreover, the threonine part was changed to various natural amino acids (Ser, Thr, Val, Leu). All the compound were screened in vivo for their analgesic effects in mouse writhing test. Compound 24 (H-Orn-Hyp-Val-OH), the most active compound within the series, showed an ED50 value of 10 mg/kg, which is comparable with the ED50 values exhibited by indometacin (4.1 mg/kg) and the dipeptide H-Lys-D-Pro-OH (6.9 mg/kg), both used as reference drugs.

Acetic Acid↗
PubMed1996

Depressive symptoms and quality of life in home-care-assisted cancer patients.

To examine the prevalence of depressive symptoms and its relationship with quality-of-life domains in home-care cancer patients at an advanced stage of illness, 86 patients were given psychological tests for depression (Hospital Anxiety Depression Scale) (HAD) and quality of life (EORTC-QLQ-C30) 1 week after admission to the home-care program. Using a proper cut-off score on the HAD-Depression subscale, depressive symptoms were reported by 45% of the patients. The quality of life of depressed patients was more affected than non-depressed patients in the social, emotional, cognitive, and physical domains. Significant correlations were found between depression scores and impairment in most quality-of-life areas. These findings support the importance of depression and quality-of-life evaluation in patients with advanced cancer who are followed in a home-care setting. This evaluation is needed to provide patients, their families, and caregivers with appropriate psychosocial interventions.

Adult↗
PubMed1996

Structure and absolute stereochemistry of fusaproliferin, a toxic metabolite from Fusarium proliferatum.

Fusaproliferin is a toxic sesterterpene isolated from Fusarium proliferatum, a widespread pathogen of cereals. Its absolute configuration has been determined by single crystal X-ray diffraction analysis. Fusaproliferin is considered to be a sesterterpene with a new ring skeleton having four C = C double bonds and four chiral atoms. The configurations of the four chiral atoms C10, C14, C15, and C19 are (R), (S), (R), and (S), respectively. In the solid state the macrolide shows a concave hydrophobic surface and hydrophilic convex face. The absolute configuration of C14 and C15 is the same as that observed for retigeranic acid, consistent with fusaproliferin being formed via a sesterterpenic-type biosynthetic pathway.

Animals↗
PubMed1996

p53 expression in colorectal cancer: relation to tumor type, DNA ploidy pattern and short-term survival.

p53 protein expression was evaluated in a series of 204 primary colorectal adenocarcinomas by immunohistochemistry using frozen tissue sections and monoclonal antibody DO-7. Nuclear staining of more than 5% of neoplastic cells was observed in 124 (60.8%) adenocarcinomas, which were classified as p53 positive. p53 immunoreactivity was found to he unrelated to several clinical and pathologic variables, including age and sex of patient, tumor site, tumor stage, grade of differentiation, pattern of growth, degree of peritumoral lymphocytic infiltration, and venous invasion. A strong association was demonstrated between p53 immunostaining and tumor type. Only 4 of 21 mucinous carcinomas examined (19%) were p53 positive. Conversely, 120 of 183 (65.6%) nonmucinous adenocarcinomas showed positive p53 immunostaining (P <.0001). p53 expression also was related to the flow cytometric DNA ploidy pattern, aneuploid carcinomas with DI >1.20 showing higher frequency of p53 overexpression than DNA diploid, and aneuploid tumors with DI < or = 1.20 (P = .0003). No relationship was found between p53 expression and the Ki-67 proliferation index. With respect to the total study population (mean follow-up 33.4 months; range 19-47 months) the duration of overall survival was independent of p53 expression. In the group of 141 patients with stage I, stage II, and stage III disease who had undergone curative resection, positive p53 immunostaining was associated with poorer overall survival (P = .029). Subgroup analysis showed that the reduced survival conferred by p53 overexpression was confined to patients with stage III tumors (P = .027). However, in multivariate analysis, p53 expression failed to demonstrate independent prognostic significance. Our results indicate that immunohistochemical analysis of p53 expression provides valuable information for the understanding of colorectal cancer biology and clinical behavior.

Adenocarcinoma↗
PubMed1996

Influence of ochratoxin A treatment on the activity of membrane bound enzymes in rat brain regions.

Ochratoxin A is a mycotoxin produced by Aspergillus ochraceus and is a natural contaminant of mouldy food. We examined the neuroactive potential of ochratoxin A by measuring the changes in the activities of several membrane bound, cytoplasmic and lysosomal enzymes in the brain of adult female rats, following subchronic application of ochratoxin A. The activities of both soluble and membrane bound fractions of ecto-5'nucleotidase, ecto-Ca2+/Mg2+ATPase, alanine aminopeptidase, gamma-glutamyl transferase, as well as activities of lactate dehydrogenase and of N-acetyl-beta-D-glucosaminidase were followed. Biochemical effects were examined in cerebral cortex, cerebellum and hippocampus. The results obtained showed physiologically significant alterations in the activity of enzymes tested. The changes were found to be time-dependent and regionally selective. Compared to controls, statistically significant increases in gamma-glutamyl transferase were observed in all three brain regions, while in the case of alanine aminopeptidase activities differed with regard to region, the highest increase being observed in hippocampus. Ecto-Ca2+/Mg2+ATPase and ecto-5'nucleotidase showed distinct changes lasting for 20 days of treatment, while increase in the activities of N-acetyl-beta-D-glucosaminidase and lactate dehydrogenase were visible only at the beginning of the treatment. By the end of the trial the activities of almost all enzymes returned back to normal values.

Animals↗
PubMed1996

The quantification of tertiary dentine formation in response to materials commonly placed in deep cavities in general practice in the UK.

PURPOSE OF STUDY: To determine the rate of formation of tertiary dentine in dogs' teeth, in response to five commonly used lining materials. Also, to record the resulting differences in quality of the formed dentine. MATERIALS AND METHODS: Representatives of five types of materials commonly used in general practice in the UK were placed in deep standardised cavities with a remaining dentine thickness of 400-500 microns, and sealed to the cavo-surface with zinc oxide-eugenol. The daily rate of tertiary dentine formed in response to each material was measured over a period of 119 days using a tetracycline staining method. A concomitant study to show the quality of the formed dentine was undertaken using the same materials and experimental conditions. RESULTS: There was a significant difference between the rates of tertiary dentine formation for all materials except zinc oxide-eugenol and Ledermix paste. For each material there was a increased rate of tertiary dentine formation in the second period (29-49 days) compared to the first period (0-28 days). This is considered to be due, in part, to a lag period when damaged odontoblasts are differentiating from mesenchymal elements. The rate of tertiary dentine formation in response to all the test materials was always greater than that of normal physiological dentine formation in unprepared teeth. Qualitatively, there was difference in the formed tertiary dentine beneath each material. All the materials caused odontoblast destruction, altered ground substance production and alterations in the calcification process. CONCLUSION: None of the materials routinely used at present can be considered to be 'ideal' as odontoblast destruction, altered ground substance production and altered calcification occur beneath zinc oxide-eugenol preparations, calcium hydroxide preparations as well as in response to corticosteroid-containing materials such as Ledermix paste and cement.

Analysis of Variance↗
PubMed1996

The diagnosis, classification and treatment of acute pulpal pain by UK general dental practitioners: results of a survey.

There are several problems related to the diagnosis and treatment of the acute painful tooth associated with a deep carious lesion, including the fact that there is little or no correlation between the clinical signs and symptoms and also that the diagnostic tools are not reliable. It is important to understand the problems experienced by dental practitioners and how they routinely make diagnosis and formulate treatment plans. The way general dental practitioners diagnosed, categorised and treated teeth with acute pain was ascertained by a questionnaire completed by practitioners attending postgraduate courses. The results indicate that dental radiographs and the dental history were most frequently used and that few practitioners had, and fewer used electric pulp testers. The concept of using simple clinical categories which correspond to treatment categories does not seem to be in widespread use, though the generally accepted role of calcium hydroxide as an indirect and direct capping material is widespread. The use of corticosteroid materials is not as widespread in younger practitioners as in their older colleagues and the use of emergency pulpotomy is infrequent.

Acute Disease↗
PubMed1995

Synthesis and biological activity of tripeptide FR113680 analogues containing unconventional amino acids.

In order to further develop structure-activity relationships and to get information about the biological active conformations we synthetized analogues tripeptide to the FR 113680 [Ac-Thr-D-Trp(CHO)-PheNMeBzl; Ac: acethyl], in which the phenylalanine residue was replaced by unconventional amino acids [1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic); (3aS, 7aS)-octahydroindole-2-carboxylic acid (Oic); (S,S,S)-2-azabiciclo[3.3.0]octane-3-carboxylic acid (Aoc); 3-(1'-naphthyl)alanine (Nap); phenylglicine (Phg); thienylalanine (Thi)]. The biological activity of the peptides was performed on guinea pig ileum for neurokinin 1 (NK-1) and on rat colon for neurokinin 2 (NK-2). In particular, the replacement of the Phe3 by the Oic (8a) gave an higher antagonist activity in both NK-1 and NK-2 receptors, but no improvement in selectivity with respect to reference tripeptide (FR113680). The compound (8a) represent the first example of highly potent peptides that do not contain an aromatic amino acid of the third position as had been previously considered essential.

Amino Acid Sequence↗