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Biomedical subjects

M Ferrari

Publications and source records attributed to M Ferrari.

At least 127 records · Page 7Linked to original sources
PubMed2001

Comparison of two spatially resolved near-infrared photometers in the detection of tissue oxygen saturation: poor reliability at very low oxygen saturation.

Two spatially resolved oximeters, NIRO-300 and OM-200, were compared with regard to the measurement of oxygen saturation values in two forearm muscle groups at rest and during arterial occlusion in nine healthy volunteers. There was a significant correlation between the muscle oxygen saturation values obtained at rest using the two oximeters (n=33, r(2)=0.43, P<0.0001), whereas these values were significantly different during arterial occlusion. Thus, although there was good agreement between muscle oxygen saturation values measured using the two oximeters, the operating range of the tissue oximeters should be recognized and indicated.

Adult↗
PubMed2001

Orthodontic-restorative treatment of chipped or worn incisors.

PURPOSE: To evaluate the shear bond strength of esthetic adhesive restorations for worn or fractured incisal edges. MATERIALS AND METHODS: On 30 human extracted incisors the edge was reduced and a bevel was prepared in the thickness of enamel. Then, the incisal edges were restored, using a different adhesive system in each of the three groups to which the sample teeth had been randomly assigned. Group A: Scotchbond Multi-Purpose Plus, in combination with phosphoric acid, and Z100 as a restorative material. Group B: Scotchbond 1 after etching with phosphoric acid, plus Z100. Group C: F2000, a compomer, in combination with its Primer/Adhesive. The differences in the bond strength values among the three groups were tested for statistical significance. Also, the resistance to load of the restored teeth was compared with that of 10 intact incisors (Group D) (controls). A statistical analysis was performed to test the significance of the differences. RESULTS: No statistically significant difference in shear bond strength was found between Scotchbond Multi-Purpose Plus (17.6 MPa) and Scotchbond 1 (14.8 MPa), whereas F2000 gave significantly lower bond strength values (10.1 MPa). As compared with intact incisors, the teeth restored with either Scotchbond Multi-Purpose Plus or Scotchbond 1 did not perform significantly differently under load. On the other hand, the incisors restored with F2000 gave, as compared with the controls, a resistance to loads significantly lower and of a questionable reliability from a clinical standpoint. SEM observations performed on some of the samples revealed that when phosphoric acid was used to condition the substrate, a deep and uniform demineralization of the enamel was effected, and a mechanically retentive interlocking was created at the interface between resin and enamel. The Adhesive/Primer of F2000 was unable to produce an equally retentive morphology.

Acid Etching, Dental↗
PubMed2001

Clinical procedure for luting glass-fiber posts.

PURPOSE: This report presents clinical cases in which a self-activating dual-cure adhesive system was used in combination with proprietary self-curing resin cement for bonding a translucent glass-fiber post. The clinical luting procedure of a self-activating bonding/self-curing resin cement system in combination with a glass-fiber post based on fiber-reinforced technology is documented. MATERIALS AND METHODS: The glass-fiber post was placed into a root canal preparation under clinical conditions and documented. A few restored teeth were extracted after 1 week and processed for SEM observations to determine the bonding mechanism to root dentin under clinical conditions. RESULTS: The SEM observations clearly showed that the bonding mechanism between Excite Dual Cure and root dentin was based on hybrid layer, resin tag, and adhesive lateral branch formation. CONCLUSION: The luting procedure described is simple and easy, and can be proposed as a daily clinical technique.

Acid Etching, Dental↗
PubMed2000

Immediate changes of collateral function after successful recanalization of chronic total coronary occlusions.

BACKGROUND: Coronary collaterals are essential to maintain myocardial function in chronic total coronary occlusions (TCOs). The aim of the present study was to assess the collateral circulation in TCOs before coronary angioplasty and to determine the recruitable collateral perfusion after recanalization by use of intracoronary Doppler flow velocimetry. METHODS AND RESULTS: In 21 patients with TCOs (duration >4 weeks), Doppler recordings of basal collateral flow were obtained before the first balloon inflation. Angioplasty was performed with stent implantation in all lesions. At the end of the procedure, recruitable collateral flow was measured during a repeat balloon inflation. The collateral flow index (CFI) was calculated from the velocity integral during the occlusion/velocity integral of antegrade flow. In 17 of 21 patients, angiography was repeated after 24 hours, and CFI was reassessed. Average peak velocity of collateral flow was 10.9+/-5.6 cm/s with a predominantly systolic flow (diastolic/systolic velocity ratio <0.5) compared with antegrade flow (diastolic/systolic velocity ratio >1.5). After recanalization, the average peak velocity of recruitable collateral flow dropped by >50% to 4.7+/-2.5 cm/s. CFI fell from 0.48+/-0.25 to 0.21+/-0.16 (P:<0.001). There was no further change of CFI during the following 24 hours. CFI was higher in patients with preserved regional ventricular function than in those with akinetic myocardium (0.57+/-0.23 versus 0.38+/-0.12, P:<0.05). CONCLUSIONS: Collateral circulation in TCO provided 50% of antegrade coronary flow. A considerable fraction of collateral flow was immediately lost after recanalization, indicating that TCO may not remain protected from future ischemic events by a well-developed collateral function.

Aged↗
PubMed2000

Adsorption and partitioning of surfactants in liquid-liquid systems.

The adsorption at liquid-liquid interfaces is a phenomenon with a remarkable impact on many scientific and technological fields concerning multiphasic systems. Though in principle similar to liquid-vapour, the study and the description of the dynamic aspects of the adsorption processes at liquid-liquid interfaces deserves some specific considerations. In fact, these systems are often characterised by the partitioning of the surfactant between the two liquid phases, which makes much more complex both their modelling and investigation. In some conditions, the partitioning can be the main process controlling the adsorption dynamics. This paper is aimed at reviewing the state-of-the-art of the theoretical modelling and experimental investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. After a brief introduction to the problem of adsorption dynamics, the principal models utilised to describe the process at liquid-liquid interfaces under different assumptions are critically presented, underlining the influence of the surfactant partitioning, with respect to the relative volumes of the liquid phases and of the initial partitioning conditions. The most important experimental methodologies for the measurement of the dynamic interfacial tension are also critically reviewed by pointing out the specific problems related with the investigation of the adsorption dynamics of surfactants at liquid-liquid interfaces. Moreover, the problem of the measurement of the thermodynamic quantities characterising the partitioning--mainly the partition coefficient--is also addressed, reporting some literature data. Finally, a review of the literature about the experimental work on the subject and an overview of the needs and of the open questions is given.

Journal Article↗
PubMed2000

HPLC-ED measurement of endogenous catecholamines in human immune cells and hematopoietic cell lines.

A rapid and simple HPLC-ED method is described to identify and measure catecholamines (CTs) and their major metabolites in immune cells. Using this method, intracellular CTs were quantified in human peripheral blood mononuclear cells (PBMCs), T and B lymphocytes, monocytes and granulocytes. Immune cell subsets were separated by density gradient centrifugation and immunomagnetic cell sorting. CTs were also found in the human hematopoietic cell lines NALM-6 (pre-B) and (in smaller amounts) in Jurkat (T lymphoblastoid) and U937 (promonocytic). In cultured PBMCs, intracellular CTs were reduced by both the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine and the chromaffin granule depletant reserpine. In NALM-6 cells, both alpha-methyl-p-tyrosine and the dopamine-beta-hydroxylase inhibitor disulfiram reduced intracellular CTs, supporting the presence of active synthetic pathways in these cells. Since sympathoadrenergic mechanisms play a key role in the interactions between the immune system and the nervous system, these findings may be relevant for a better understanding of the neuro-immune network.

B-Lymphocytes↗
PubMed2000

Glutamate receptors of the AMPA type modulate neurotransmitter release and peristalsis in the guinea-pig isolated colon.

To assess the role of AMPA and kainate receptors in modulating neurotransmitter release from the myenteric plexus, the effect of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) and kainic acid on endogenous acetylcholine (ACh) and noradrenaline (NA) overflow from the guinea-pig isolated colon was studied. AMPA inhibited spontaneous ACh overflow and increased electrically-evoked NA overflow. Kainic acid did not influence both ACh and NA overflow. AMPA-mediated effects on ACh and NA overflow were significantly reduced by the AMPA/kainate antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, CNQX. The inhibitory effect of AMPA on ACh overflow could be due, at least in part, to the AMPA-induced NA overflow as it was greatly reduced after adrenoceptor blockade and virtually abolished in sympathetically-denervated animals. The possible functional significance of these findings was studied by measuring the efficiency of the peristaltic reflex in the presence of the different agonists. The efficiency of peristalsis was enhanced by AMPA, whereas it was not modified by kainic acid. In conclusion, AMPA receptors, but not kainate receptors, may play a role in the modulation of ACh and NA release and of peristalsis in the guinea-pig colon.

Acetylcholine↗
PubMed2000

DNA damage checkpoints and DNA replication controls in Saccharomyces cerevisiae.

In response to genotoxic agents and cell cycle blocks all eukaryotic cells activate a set of surveillance mechanims called checkpoints. A subset of these mechanisms is represented by the DNA damage checkpoint, which is triggered by DNA lesions. The activation of this signal transduction pathway leads to a delay of cell cycle progression to prevent replication and segregation of damaged DNA molecules, and to induce transcription of several DNA repair genes. The yeast Saccharomyces cerevisiae has been invaluable in genetically dissecting the DNA damage checkpoint pathway and recent findings have provided new insights into the architecture of checkpoint protein complexes, in their order of function and in the mechanisms controlling DNA replication in response to DNA damage.

Cell Cycle↗
PubMed2000

Synthesis and immunosuppressive activity of novel prodigiosin derivatives.

Prodigiosins (Ps) represent a family of naturally occurring red pigments characterized by a common pyrrolylpyrromethene skeleton. Some members of this family have been shown to possess interesting immunosuppressive properties exerted with a novel mechanism of action, different from that of currently used drugs. In fact, Ps inhibit phosphorylation and activation of JAK-3, a cytoplasmic tyrosine kinase associated with a cell surface receptor component called common gamma-chain, which is exclusive of all IL-2 cytokine family receptors. Blocking common gamma-chain transduction activity results in a potent and specific immunosuppressive activity. With respect to the interesting and unexploited immunomodulating properties of this family of compounds we initiated a medicinal chemistry program aimed at finding novel prodigiosin derivatives with improved immunosuppressive activity and lower toxicity. Utilizing an unprecedented and flexible way of assembling the prodigiosin frame, a number of new derivatives have been prepared and tested leading to the choice of 4-benzyloxy-5-[(5-undecyl-2H-pyrrol-2-ylidene)methyl]-2, 2'-bi-1H-pyrrole (PNU-156804, 16) as a lead immunosuppressant.

Animals↗
PubMed2000

Migraine with aura and white matter abnormalities: Notch3 mutation.

The authors report on an Italian family with eight affected members who show autosomal dominant migraine with prolonged visual, sensory, motor, and aphasic aura. These symptoms are associated with white matter abnormalities on brain MRI. All living affected members carry a Notch3 mutation (Arg153Cys) previously reported in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). White matter abnormalities occur in a variable percentage of the general migraine population; CADASIL should be suspected in migraineurs with prolonged atypical aura and white matter abnormalities.

Brain↗
PubMed2000

Non-surgical extraction of right cardiac "thrombus in transit".

In two hemodynamically unstable patients, massive pulmonary embolism and free-floating right cardiac thrombi were diagnosed. Thrombolytic therapy was contraindicated and surgical treatment was rejected. In these two cases, we describe a successful non-surgical, percutaneous extraction of mobile right cardiac thrombi. Cathet. Cardiovasc. Intervent. 51:316-319, 2000.

Echocardiography, Transesophageal↗
PubMed2000

Influence of ceramic and cement thickness on the masking of various types of opaque posts.

STATEMENT OF PROBLEM: Dark-colored posts may negatively affect the esthetics of all-ceramic single unit crowns as the thin layers of luting cement may not be sufficiently opaque. PURPOSE: This in vitro study evaluated the influence of the color of 2 commercially available nonmetallic opaque posts (carbon fiber and zirconia) and an experimental esthetic post, and the shade and thickness of luting cements on the esthetics of all-ceramic restorations. MATERIAL AND METHODS: Sample disks at several thickness values were made in glass-ceramic (IPS-Empress), an experimental ceramic, a zirconia, a carbon fiber post material, a resin composite material (Z100) as reference, and a luting cement (Variolink II). A laboratory procedure, with 3 possible combinations of stapling the disks, was used. This was performed for 4 substrates, 3 cement colors at 2 thickness values, and 3 heights of ceramic disks. For each combination, the shift in color was measured with a spectrophotometer. Readings were performed for 3 conditions: (1) ability of ceramic to mask the aspect of the abutment in relation to its thickness (1.0, 1.5, or 2.0 mm); (2) effect of a change in cement color (W, Y, or B) on the final color of the ceramic; and (3) influence of cement film thickness (0.1 or 0.2 mm) on the final color of the ceramic. RESULTS: When ceramic thickness was 1 mm, all other variables were visually appreciable. For ceramic thickness of 1.5 mm, color differences decreased and most differences were appreciable only with laboratory instruments. For ceramic thickness of 2.0 mm, there were no detectable, clinically relevant differences. CONCLUSION: The final esthetic result of the all-ceramic IPS-Empress glass-ceramic restoration was not affected by the presence of different substrates with different colors when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5 mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0 mm, the use of a full ceramic crown is contraindicated because color matching of the abutment is required to ensure an acceptable esthetic result. Differences in cement thickness (0.1 or 0.2 mm) may slightly affect the final result. As this parameter can be controlled by the operator only to a certain extent, it cannot be considered as a procedure to correct color. Availability of different cement shades allows only minor esthetic corrections, which might be instrumentally detectable but are clinically not relevant.

Aluminum Silicates↗
PubMed2000

The response of pigs inoculated with a thymidine kinase-negative (TK-) pseudorabies virus to challenge infection with virulent virus.

12 Large-White-Landrace piglets were subdivided in four groups of 3 and housed in separate units. The piglets of three groups were inoculated with the 86/27V 6C2 thymidine kinase negative (TK-) mutant of pseudorabies virus (PRV), by different routes. A second inoculation with the same mutant was given to the pigs 21 days later. The animals of a fourth group were left as uninoculated controls. 21 days following the second inoculation with the TK- mutant all pigs were challenge infected with the virulent PRV. On post challenge day (PCD) 30 all pigs were killed and samples for virus detection and histology were taken from several organs. The inoculated TK- mutant of PRV did not induce any ill effects in the pigs except a transient febrile reaction in some animals. Virus was recovered from nasal swabbings from one pig 2 days after the first inoculation of the mutant. After challenge exposure with virulent PRV, the TK- mutant-inoculated pigs were apparently protected, whereas the control pigs all were severely affected and recovered very slowly over 3 weeks. Virus was isolated from the nasal swabbings from the TK- mutant-inoculated pigs on PCDs 2 and 4, whereas the nasal swabbings from the control piglets were all positive for virus from PCD 2 through PCD 10. DNA analysis of the virus recovered showed a pattern identical to that of the virulent PRV. Histologic lesions were found in the respiratory and the central nervous systems, however, the lesions in the TK- mutant-inoculated pigs were much milder compared to those registered for the control pigs. Virus was not isolated from any of the tissue samples that were tested, but viral DNA with sequences typical of PRV genome was detected by PCR in all samples of trigeminal ganglia from either the TK- mutant-inoculated pigs or from the controls.

Administration, Intranasal↗
PubMed2000

The use of immunomodulators in the control of infectious bovine rhinotracheitis.

Three experiments have been carried out to verify the effectiveness of an immunomodulator, Baypamun (Bayer AG) in limiting the spread of Bovine herpesvirus-1 (BHV-1), the causal agent of infectious bovine rhinotracheitis (IBR). In the first experiment, four calves infected with BHV-1 developed severe disease whereas four calves given Baypamun simultaneously with the virus had less severe disease. Four other calves in contact with the infected calves became severely ill but another four given Baypamun were only mildly affected. In the second experiment three calves infected with BHV-1, which reacted with typical disease, were allowed to remain in contact with six calves. All six calves were given Baypamun at various times following the exposure to BHV-1 infection and all showed a much reduced reaction with two treated for 4 days developing no clinical disease. Finally, in the third experiment one calf vaccinated one month before the start of the experiment did not develop any signs of disease when housed together with a calf experimentally infected with BHV-1. Of four other calves, vaccinated when the infected calf showed the first signs of disease, only the two given Baypamun in addition to the vaccine, were protected from clinical disease whereas the two given vaccine only developed classical signs of IBR. In the three experiments the virus shedding by the Baypamun-treated calves resulted to be significantly reduced.

Adjuvants, Immunologic↗
PubMed2000

Nanoporous anti-fouling silicon membranes for biosensor applications.

The ability to create biocompatible well-controlled membranes has been an area of great interest over the last few years, particularly for biosensor applications. The present study describes the fabrication and characterization of novel nanoporous micromachined membranes that exhibit selective permeability and low biofouling. Results indicate that such membranes can be fabricated with uniform pore sizes capable of the simultaneous exclusion of albumin and diffusion of glucose. Compared to polymeric membranes of similar pore size, micromachined silicon membranes allowed more than twice the amount of glucose diffusion after 240 min and complete albumin exclusion. Moreover, membranes exhibit no morphological change or degradability in the presence of biological proteins and fluids at 37 degrees C. The results point to the potential of using such membranes for implantable biosensor applications. With monodisperse pores sizes as small as 10 nm, these membranes offer advantages in their reproducibility, stability, and ability to be integrated in silicon-based biosensing technology.

Albumins↗
PubMed2000

Micromachined interfaces: new approaches in cell immunoisolation and biomolecular separation.

As a novel therapeutic application of microfabrication technology, a micromachined membrane-based biocapsule is described for the transplantation of protein-secreting cells without the need for immunosuppression. This new approach to cell encapsulation is based on microfabrication technology whereby immunoisolation membranes are bulk and surface micromachined to present uniform and well-controlled pore sizes as small as 10 nm, tailored surface chemistries, and precise microarchitecture. Through its ability to achieve highly controlled microarchitectures on size scales relevant to living systems (from microm to nm), microfabrication technology offers unique opportunities to more precisely engineer biocapsules that allow free exchange of the nutrients, waste products, and secreted therapeutic proteins between the host (patient) and implanted cells, but exclude lymphocytes and antibodies that may attack foreign cells. Microfabricated inorganic encapsulation devices may provide biocompatibility, in vivo chemical and mechanical stability, tailored pore geometries, and superior immunoisolation for encapsulated cells over conventional encapsulation approaches. By using microfabrication techniques, structures can be fabricated with spatial features from the sub-micron range up to several millimeters. These multi-scale structures correspond well with hierarchical biological structures, from proteins and sub-cellular organelles to the tissue and organ levels.

Animals↗