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Biomedical subjects

M Ferrari

Publications and source records attributed to M Ferrari.

At least 325 records · Page 18Linked to original sources
PubMed1994

An evaluation of the effect of the adhesive luting on microleakage of the IPS empress crowns.

In an ongoing search for improved aesthetics, new materials and techniques are being developed and evaluated for clinical application; all-ceramic crown systems are among them. This paper presents an in vitro evaluation of the effect of dentin and porcelain bonding, with luting resin, on microleakage of porcelain crowns. Clinical application is discussed, and three cases are used to illustrate the procedure. The learning objective of this article is to enhance the knowledge of the more recent developments in dental materials and application techniques.

Aluminum Silicates↗
PubMed1994

Traumatic injuries to permanent incisors: a case report.

A case report involving traumatized maxillary incisors is presented. The right central and lateral incisors were avulsed by direct trauma and were not found. The left central incisor was luxated and the left lateral incisor was fractured at the coronal portion. Placement of implant fixtures was selected as treatment to prevent resorption of alveolar bone and to maintain the integrity of intact adjacent teeth. The right incisors were replaced with two osseointegrated implants. The left central incisor was endodontically treated and a cast post and core was bonded into the root canal. All three of these teeth were restored with porcelain-fused-to-metal crowns. A composite resin restoration was placed on the left lateral incisor. The esthetic and functional results were satisfactory.

Accidents, Traffic↗
PubMed1993

De novo synthesis of budding yeast DNA polymerase alpha and POL1 transcription at the G1/S boundary are not required for entrance into S phase.

The POL1 gene, encoding DNA polymerase alpha (pol alpha) in Saccharomyces cerevisiae, is transiently transcribed during the cell cycle at the G1/S phase boundary. Here we show that yeast pol alpha is present at every stage of the cell cycle, and its level only slightly increases following the peak of POL1 transcription. POL1 mRNA synthesis driven by a GAL1 promoter can be completely abolished without affecting the growth rate of logarithmically growing yeast cultures for several cell divisions, although the amount of the pol alpha polypeptide drops below the physiological level. Moreover, alpha-factor-arrested cells can enter S phase and divide synchronously even if POL1 transcription is abolished. These results indicate that the level of yeast pol alpha is not rate limiting and de novo synthesis of the enzyme is not required for entrance into S phase.

Cell Cycle↗
PubMed1993

Oxygen-dependent reduction of a nitroxide free radical by electron paramagnetic resonance monitoring of circulating rat blood.

The effects of fraction of inspired oxygen (FiO2) on the reduction of a nitroxide free radical were studied by X-band electron paramagnetic resonance (EPR) monitoring of circulating rat blood. The decay half-life of the metabolism/elimination phase increased significantly by 24 +/- 8% during hyperoxia and decreased significantly by 16 +/- 4% during hypoxia.

Animals↗
PubMed1993

Proliferation index as a prognostic marker in breast cancer.

BACKGROUND: The proliferative activity of tumors has been extensively investigated with different approaches, among which the use of the monoclonal antibody Ki-67 represents an easy and reliable means of assessing cell proliferation. In this study, the proliferative activity of 129 primary breast cancers was investigated, and the results were related to prognosis. METHODS: Tumor samples, obtained from 129 patients who underwent surgery between January 1987 and December 1988, were processed for staining by an immunohistochemical procedure (avidin-biotin complex). The median time of observation was 42 months (range, 31-55 months). Life-table analysis (Mantel-Cox) was used to assess the probability of disease-free survival (DFS) and overall survival (OS). RESULTS: Tumors with high Ki-67 proliferation indices (> 20%) were associated with a higher 4-year probability of relapse of disease (55.3% versus 79.1%; P = 0.003) and death (71% versus 95.6%; P = 0.00005) when compared with tumors with low Ki-67 values. In addition, this proliferative parameter maintained its prognostic significance when the patients were stratified according to lymph node involvement, menopausal status, and nuclear estrogen receptor content. CONCLUSIONS: Tumor proliferative activity as evaluated by the monoclonal antibody Ki-67 seems to be an effective indicator of prognosis in breast cancer for DFS and OS.

Biomarkers, Tumor↗
PubMed1993

Noninvasive measurement of human forearm oxygen consumption by near infrared spectroscopy.

This study reported on the application of near infrared spectroscopy (NIRS) to noninvasive measurements of forearm brachio-radial muscle oxygen consumption (VO2) and recovery time (tr) in untrained volunteers. Seven healthy subjects were submitted to four consecutive protocols involving measurements made at rest, the induction of an ischaemia, and during a maximal increase of metabolic demand achieved with and without vascular occlusion. Two isometric maximal voluntary contractions (MVC) of 30-s duration were executed with and without vascular occlusion and a 50% MVC lasting 125 s was also performed. The protocols were repeated on 2 different days. The results showed that, during vascular occlusion at rest, the time to 95% of the final haemoglobin (Hb) + myoglobin (Mb) desaturation value was independent of VO2. The MVC, performed during vascular occlusion, caused complete Hb+Mb desaturation in 15-20 s, which was not followed by any further desaturation when the second contraction was performed. No difference was found between VO2 during MVC with and without vascular occlusion. A consistent difference was seen between VO2 measured during occlusion at rest and VO2 measured during MVC with and without occlusion. During prolonged exercise (125 s) Hb+Mb desaturation was maintained for the whole contraction period. The results of this study show that VO2 can be measured noninvasively by NIRS. The VO2 during MVC was very similar both in the presence and absence of blood flow limitation in most of the subjects tested. This would suggest that muscle VO2 might be accurately evaluated dynamically without cuff occlusion.

Adult↗
PubMed1993

Basic fibroblast growth factor and its receptor messenger ribonucleic acids are expressed in human ovarian epithelial neoplasms.

OBJECTIVE: Our purpose was to determine whether basic fibroblast growth factor is present in, and synthesized by, human ovarian epithelial neoplasms and to evaluate the expression of gene for the basic fibroblast growth factor receptor. STUDY DESIGN: The synthesis of basic fibroblast growth factor and its receptor was investigated in seven primary human ovarian epithelial neoplasms. Neoplastic tissues were homogenized and the cytoplasmic extracts purified by heparin-sepharose chromatography with a linear salt gradient of 0.6 to 3 mol/L sodium chloride in Tris-hydrochloric acid. The in situ synthesis of basic fibroblast growth factor and its receptor was demonstrated by polymerase chain reaction. Total ribonucleic acid was reverse transcribed and then amplified with two oligonucleotide primers specific for the bovine and human basic fibroblast growth factor gene and its human receptor gene. RESULTS: As assessed by both bioassay and radioimmunoassay a peak of basic fibroblast growth factor-like activity was present in all tumors in the chromatographic fractions eluted with 3 mol/L sodium chloride. The mitogenic effect on bovine adrenocortical endothelial cell proliferation varied from 35% to 153% above control cultures. Levels of basic fibroblast growth factor-like immunoreactivity were between 4 and 33 ng/ml. Qualitatively similar results were obtained after purifying the cytoplasmic extract of dispersed human ovarian tumor cells. The mitogenic effect was completely abolished by a specific neutralizing anti-basic fibroblast growth factor antibody. Single major deoxyribonucleic acid bands of the expected size (354 and 661 bp) were detected in all tumors studied. The identify of this material with the human basic fibroblast growth factor sequence was confirmed by restriction enzyme analysis. CONCLUSION: These data demonstrate that both basic fibroblast growth factor and its receptor are present in and synthesized by human ovarian tumor cells. Thus basic fibroblast growth factor might stimulate their abnormal proliferation through an autocrine mechanism.

Carcinoma↗
PubMed1993

Preliminary report of an experimental design for in vivo testing of bonded restorations applied to a new enamel-dentinal bonding agent.

Because of inconsistency often found between in vitro testing and in vivo performance, a new restorative bonding system was evaluated by the placement of restorations in vivo in teeth to be extracted. The microleakage was determined following extraction after 3 months of clinical service. In each of the sample teeth, two restorations were placed on the labial surface, one in the middle of the enamel portion and the other extending over the cementoenamel portion. The results of this pilot study indicated that bonding to conditioned enamel with the new adhesive material is effective, and bonding to conditioned dentin appears to be clinically adequate.

Acid Etching, Dental↗
PubMed1993

Field evaluation of the efficacy of Romovac 50, a new inactivated, adjuvanted bovine rotavirus vaccine.

An inactivated bovine rotavirus vaccine, prepared with an adjuvant which gives a water-in-oil emulsion (Montanide ISA 50, adjuvant) was used in field trials for prevention of calf neonatal diarrhoea. The vaccine, which was designated as Romovac 50, when injected into cows in their last month of pregnancy, proved to be as effective as the traditional vaccine prepared with Freund's incomplete adjuvant. Thus, the incidence of the naturally occurring neonatal diarrhoea was significantly reduced in calves which were fed mammary secretion from their vaccinated dams, compared to the calves delivered from the unvaccinated cows. Romovac 50 also has the advantages over the traditional Freund's adjuvanted vaccine in that it is less viscous and thus more readily injected and less irritant to tissues.

Adjuvants, Immunologic↗
PubMed1993

Expression of the genes encoding basic fibroblast growth factor and its receptor in human granulosa cells.

The role of basic fibroblast growth factor (bFGF) in granulosa cell ontogeny has been previously demonstrated. In this study we evaluated the possible intraovarian origin of bFGF. Human granulosa cells were maintained in primary culture and their cytoplasmic extract was purified by affinity chromatography on a heparin-sepharose column. The column was then eluted with 10 mM Tris-HCl containing increasing concentrations of NaCl. The chromatographic fractions were tested in a bioassay using bovine adrenal capillary endothelial cells (ACE) as targets. A peak of mitogenic activity was detected in the fraction eluted with the highest salt concentration. This chromatographic profile is similar to that of bFGF. The in situ synthesis of this bFGF-like protein was then demonstrated by reverse transcription-polymerase chain reaction. Using oligonucleotide primers specific for the bFGF gene, a single major band of DNA, corresponding to the expected size, was amplified. The identity of this fragment with the bFGF corresponding sequence was further demonstrated by restriction enzyme analysis. Moreover, RT-PCR was also employed to amplify a DNA band specific for the bFGF receptor gene. These data indicate that human granulosa cells are able to synthesize both bFGF and its receptor and, thus, bFGF might participate to the autocrine mechanisms regulating their growth and differentiated functions.

Adrenal Cortex↗
PubMed1993

Early detection of residual prostate cancer after radical prostatectomy by an ultrasensitive assay for prostate specific antigen.

We evaluated the usefulness of an ultrasensitive immunoassay for prostate specific antigen (PSA), modified from the standard Yang Pros-Check PSA test and with a biological detection limit for PSA in serum of 0.07 ng./ml., to detect residual prostate cancer at an earlier date. We studied retrospectively serial frozen serum samples from 22 prostate cancer patients after radical prostatectomy who later had residual cancer with detectable PSA levels of 0.3 ng./ml. or more by the standard PSA test. As controls we studied 33 cystoprostatectomy patients (for bladder cancer) without histological evidence of prostate cancer and 23 patients after radical prostatectomy who had the highest probability of cure of the cancer. All control patients without cancer had PSA values (282 of 283 samples, 99.6%) of less than 0.1 ng./ml. This value was called the residual cancer detection limit. In the 22 patients with recurrent cancer the ultrasensitive assay detected cancer recurrence (PSA 0.1 ng./ml. or more) much earlier (median 202 and mean 310 days) than the standard assay (PSA 0.3 ng./ml. or more). On screening 187 current post-radical prostatectomy patients without evidence of cancer by the standard assay the ultrasensitive assay detected 21 (11.2%) with evidence of residual cancer, that is PSA level of 0.1 ng./ml. or more. We conclude that an ultrasensitive assay for PSA can detect residual cancer after radical prostatectomy much earlier than current immunoassays for PSA. Earlier detection of residual cancer may improve long-term survival by allowing for earlier institution of adjuvant therapy.

Aged↗
PubMed1993

Pharmacodynamic variability of flecainide assessed by QRS changes.

The effect of flecainide on the QRS interval was studied in 10 patients who were receiving long-term oral treatment (50 to 150 mg twice daily) for arrhythmias that were refractory to other drugs. Total and free drug plasma levels and QRS durations were measured at intervals after the morning administration. Free drug plasma levels were linearly correlated with QRS duration in each patient and the slope of the line was widely variable in the population studied. Even after the data from one patient with an unusually high slope (0.454) was excluded from the analysis, the slope range was 0.0284 to 0.144. Pharmacodynamic variability could not be explained by heart rate changes, active metabolites, electrolyte disturbances, or free drug concentration. None of the pharmacokinetic parameters measured (average steady-state concentration, fluctuation of maximum and minimum concentrations, time to peak concentration, final half-life, and protein binding) showed an intersubject variability greater than 4.4 times. Our findings suggest that the determination of flecainide free plasma concentration may not be sufficient to forecast electrophysiologic effects in individual patients.

Administration, Oral↗
PubMed1993

Substitution of Leu for Pro-193 in the insulin receptor in a patient with a genetic form of severe insulin resistance.

Mutations have been identified in the insulin receptor (IR) gene in patients who are insensitive to insulin action. We studied an extremely insulin resistant patient whose insulin binding to Epstein-Barr virus (EBV) transformed lymphocytes was severely reduced. Transmembrane signalling, evaluated as insulin receptor autophosphorylation, was normal. The patient's IR was immunoprecipitated normally by AbP6, a polyclonal antibody directed to the beta subunit. However, there was an approximately 50% decrease in the affinity of IR immunoprecipitation by a monoclonal antibody (MA-10) directed against the alpha subunit. These observations suggested that there were likely to be a mutation in the patient's insulin receptor that caused misfolding of the IR alpha subunit. Analysis of gene structure by Southern blotting experiments did not reveal any major deletion in the IR gene of the proband. Northern blot analysis showed a normal level of expression of IR gene. We applied denaturing gradient gel electrophoresis (DGGE) as well as direct sequence analysis to study the 22 exons of IR gene amplified by polymerase chain reaction (PCR) using the proband's genomic DNA as a template. We identified a new missense mutation substituting leucine (CTG) for proline (CCG) in homozygous state at codon 193 in exon 3. Both parents are heterozygous for the Leu193 mutation. The Leu193 mutation was not detected in any of 75 normal subjects (150 chromosomes), indicating that it is not a common sequence variant of the insulin receptor. In addition, during the course of screening the patient's DNA with perpendicular DGGE, we identified two previously unreported silent substitutions in exon 9.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗