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Biomedical subjects

Marco Ferrari

Publications and source records attributed to Marco Ferrari.

At least 73 records · Page 4Linked to original sources
PubMed2004

Mapping of calf muscle oxygenation and haemoglobin content during dynamic plantar flexion exercise by multi-channel time-resolved near-infrared spectroscopy.

A compact and fast multi-channel time-resolved near-infrared spectroscopy system for tissue oximetry was developed. It employs semiconductor laser and fibre optics for delivery of optical signals. Photons are collected by eight 1 mm fibres and detected by a multianode photomultiplier. A time-correlated single photon counting board is used for the parallel acquisition of time-resolved reflectance curves. Estimate of the reduced scattering coefficient is achieved by fitting with a standard model of diffusion theory, while the modified Lambert-Beer law is used to assess the absorption coefficient. In vivo measurements were performed on five healthy volunteers to monitor spatial changes in calf muscle (medial and lateral gastrocnemius; MG, LG) oxygen saturation (SmO2) and total haemoglobin concentration (tHb) during dynamic plantar flexion exercise performed at 50% of the maximal voluntary contraction. At rest SmO2 was 73.0 +/- 0.9 and 70.5 +/- 1.7% in MG and LG, respectively (P = 0.045). At the end of the exercise, SmO2 decreased (69.1 +/- 1.8 and 63.8 +/- 2.1% in MG and LG, respectively; P < 0.01). The LG desaturation was greater than the MG desaturation (P < 0.02). These results strengthen the role of time-resolved near-infrared spectroscopy as a powerful tool for investigating the spatial and temporal features of muscle SmO2 and tHb.

Adipose Tissue↗
PubMed2004

Dopaminergic D1-like receptor-dependent inhibition of tyrosine hydroxylase mRNA expression and catecholamine production in human lymphocytes.

Activation of human peripheral blood mononuclear cells (PBMC) triggers endogenous production of catecholamines (CA) through protein kinase (PK) C-dependent induction of tyrosine hydroxylase (TH; EC 1.14.16.2), the first and rate-limiting enzyme in the synthesis of CA. Since CA themselves are major mediators of the neural input to the immune system, we have examined their ability to affect PKC-induced TH mRNA expression and CA production in human isolated PBMC. In T- and B-lymphocytes (but not in monocytes) the PKC activator 12-O-tetradecanoylphorbol-13-acetate (TPA) (but not its inactive analogue 4alpha-phorbol-12,13-didecanoate) induced TH mRNA expression which was followed by an increase in the amount of intracellular CA. Coincubation of human PBMC with dopamine (DA) (but not with norepinephrine or epinephrine) inhibited TPA-induced TH mRNA expression. The effect of DA was concentration-dependent and was mimicked by the dopaminergic D1-like receptor agonist SKF-38393 but not by the D2-like receptor agonist bromocriptine. The D1-like antagonist SCH-23390 shifted to the right the concentration-response curves of both DA and SKF-38393, while neither the D2-like antagonist domperidone, nor the alpha1-adrenoceptor antagonist prazosin, the alpha2-adrenoceptor antagonist yohimbine, or the beta-adrenoceptor antagonist propranolol affected to any significant extent the inhibitory effect of DA. SKF-38393 also significantly reduced TPA-induced increase of intracellular CA, an effect which was antagonized by SCH-23390. It is thus suggested that in human T- and B-lymphocytes PKC activation leads to TH mRNA expression and subsequent increase of intracellular CA, which can be inhibited by D1-like receptor activation. Inhibition of intracellular CA production in human PBMC promotes cell survival through reduction of activation-induced apoptosis, and dopaminergic modulation of TH expression and intracellular CA content may thus represent a novel mechanism in the cross-talk between the nervous and the immune system as well as among immune system cells.

Catecholamines↗
PubMed2004

Color and opacity variations in three different resin-based composite products after water aging.

OBJECTIVES: Correct shade selection and clinical procedures may be invalidated as a result of intrinsic color shifting with time. The aim of this study was to test the influence of exposure to water on the color stability of three structurally different resin-based composites. METHODS: Six comparable Vita shades of three different resin-based composite systems were selected. For each product at each shade, three disks were made, 1 mm in thickness and 15 mm in diameter. The samples were studied with a spectrophotometer equipped with an integrating sphere. For color determinations, a 50% gray card was used as background, and the data were recorded in the CIE L*a*b* system. Opacity was calculated as the ratio of the reflectance of a specimen disk when backed by a black standard that when backed by a white standard. After the initial measurements, the samples were stored for 30 days in a 60 degrees C water bath and then measured again under the same conditions. The color shifts were calculated using the formula: delta E = [(L1 - L2)2 + (a1 - a2)2 + (b1 - b2)2]1/2. RESULTS: If the standard of delta E < 3.3 as clinically acceptable was taken into consideration, one of the three materials involved in the study showed an unacceptable color shift for all shades. Only one of the three materials remained completely within an acceptable shade shift (delta E < 3.3) after aging. The difference in the color stability between products was significant (p < 0.001). The differences may be due to the different nature of the matrix and could also be correlated with filler particles dimensions. With reference to opacity; the results showed a similar pattern as that of the color and the statistical analysis also correlated. SIGNIFICANCE: From this work, it can be concluded that for some products, aging of composites in water leads to color instability and opacity variation.

Analysis of Variance↗
PubMed2004

Influence of substrate, shape, and thickness on microtensile specimens' structural integrity and their measured bond strengths.

OBJECTIVES: To verify whether substrate, shape, or thickness of microtensile specimens have a significant influence on their measured bond strength. METHODS: Sixty-four extracted molars provided microtensile specimens, which were prepared on enamel and dentin, in different shapes and thicknesses. The teeth were randomly divided into 16 groups (n = 4). Groups 1-8 included hourglass-shaped specimens. In Groups 1-4 specimens were prepared from enamel and in a thickness at the bonding interface of 0.5 mm x 0.5 mm, 1 mm x 1 mm, 1.5 mm x 1.5 mm, and 2 mm x 2 mm, respectively. In these same thicknesses, hourglasses were trimmed in Groups 5-8, but the specimens were prepared from dentin. Groups 9-16 included specimens obtained following the non-trimming technique. Groups 9-12 provided enamel sticks in the four evaluated thicknesses. In these same thicknesses and shape but from dentin were cut the specimens of Groups 13-16. Two specimens from each group were viewed using a scanning electron microscope. On the other ones, microtensile bond strength was measured and the values were statistically analyzed. RESULTS: Substrate, shape, and thickness of the specimens had a significant effect on their recorded bond strength (p < 0.05). Higher bond strength values were recorded by dentin versus enamel specimens and by sticks versus hourglasses. Also, bond strength decreased as specimen thickness increased. SEM analysis revealed that the trimmed specimens, especially if from enamel, often exhibited lines of fracture in the area of action of the bur. SIGNIFICANCE: It seems advisable to avoid the trimming action particularly on enamel specimens. If the hourglass shape is preferred, the cross-sectional area should not exceed 1 mm x 1 mm.

Analysis of Variance↗
PubMed2004

Water movement in the hybrid layer after different dentin treatments.

UNLABELLED: The aim of this study was to examine the morphology of the hybrid layer (HL) of bonded water-stored specimens after different chemical pre-treatments of dentin. MATERIALS AND METHODS: Twenty-seven recently extracted human molars were selected. Fifty-four dentin disks in middle/deep dentin were obtained with a slow speed saw with a diamond-impregnated disk under water lubrication. Smear layers were created with 180 grit silicon carbide under running water for 1 min. Different pre-treatments of dentin were: Group (1) no treatment; Group (2) 35% H3PO4 etch for 15 s followed by 10% glutaraldehyde for 120 s; Group (3) 37% H3PO4 etch for 15 s followed by 5% NaOCl for 120 s. Three dentin bonding agents (DBAs), Prime and Bond NT (P and B), AdmiraBond (AB), and Clearfil SE Bond (SEB) were applied in association with a resin composite following the manufacturers' directions. Each specimen was then longitudinally sectioned and polished with wet SiC papers (up to #4000 grit). Impressions of the polished dentin were immediately taken with a silicone impression material. Bonded specimens were then stored for 3 or 12 h in deionized water. Further impressions of stored specimens were taken after air-drying of specimens for 10 s. Positive replicas were obtained using a polyether impression material. All the replicas and the original specimens were inspected by SEM. RESULTS: A line of droplets (0.5-4 microm in diameter) was observed along the region of the adhesive-HL junction in all replicas of specimens stored in water, except in group 3, when P and B and AB were used. When SEB was used in each group the droplet were found in all groups except the zone of droplets was thinner. No differences in droplets dimensions were seen between 3 or 12 h water storage, or between the different dentin treatments. CONCLUSIONS: The replica procedure used in this study was able to detect water trapped in the adhesive-HL region that was released during the setting of the impression material. The droplets observed in this region support the hypothesis that there can be bidirectional water movement within the adhesive-HL complex.

Acid Etching, Dental↗
PubMed2004

Surface debris of canal walls after post space preparation in endodontically treated teeth: a scanning electron microscopic study.

PURPOSE: To evaluate surface cleanliness of root canal walls along post space after endodontic treatment using 2 different irrigant regimens, obturation techniques, and post space preparation for adhesive bonding. STUDY DESIGN: Forty teeth, divided into 4 groups, were instrumented, using Ni-Ti rotary files, irrigated with NaOCl or NaOCl+EDTA and obturated with cold lateral condensation (CLC) or warm vertical condensation (WVC) of gutta-percha. After post space preparation, etching, and washing procedure, canal walls were observed using a scanning electron microscope (SEM). Amount of debris, smear layer, sealer/gutta-percha remnants, and visibility of open tubules were rated. RESULTS: Higher amounts of rough debris, large sealer/gutta-percha remnants, thick smear layer, and no visibility of tubule orifices were recorded in all the groups at apical level of post space. At middle and coronal levels areas of clean dentin, alternating with areas covered by thin smear layer, smaller debris, gutta-percha remnants, and orifices of tubules partially or totally occluded by plugs were frequently observed. CONCLUSIONS: After endodontic treatment, obturation, and post space preparation SEM analysis of canal walls along post space shows large areas (covered by smear layer, debris, and sealer/gutta-percha remnants) not available for adhesive bonding and resin cementation of fiber posts.

Acid Etching, Dental↗
PubMed2004

Micromorphology of the fiber post-resin core unit: a scanning electron microscopy evaluation.

OBJECTIVES: [corrected] To microscopically evaluate the structural characteristics of post-and-core units made with a fiber post and different types of composite resins used as build-up materials. MATERIALS AND METHODS: Forty endodontically treated human maxillary incisors were prepared for receiving a fiber post (Aesthetic Post Plus, RTD). One-Step (Bisco) was used as a bonding material, and C&B resin cement (Bisco) for luting the post. The posted roots were randomly divided into eight groups. In each group a different material or technique was applied to build up the abutment. The materials on trial were Z100 (3M-ESPE), Lumiglass (RTD), Gradia (GC), Build-it! (Jeneric Pentron). On the specimens of Groups 5-8, the same materials were used for build-ups, with the addition of a preshaped plastic shell (Composipost, Core Form, RTD). All the post-and-core specimens were cut perpendicular to their long axis and processed for SEM observation. The objective was to detect the presence of voids/bubbles within the resin abutment, and of gaps at the interface between the post surface and the core material. These aspects were quantified with reference to indexes. The differences among the scores were tested for statistical significance (p<0.05). RESULTS: In the absence of any matrix, cores built up with Gradia showed the highest integrity, and those made with Z100 the best adaptation onto the post. In the presence of shells, Build-it! provided the most satisfactory result. Build-it! was the only material to perform better when used in combination with a shell. SIGNIFICANCE: When hybrid composites are used to build up a core onto a fiber post, a higher homogeneity of the abutment and a better post-core integration are achieved if the build up is done in the absence of any matrix.

Composite Resins↗
PubMed2004

The adhesion between fiber posts and root canal walls: comparison between microtensile and push-out bond strength measurements.

Aim of the study was to compare the trimming and non-trimming variants of the microtensile technique with the 'micro' push-out test in the ability to measure accurately the bond strength of fiber posts luted inside root canals. In 15 endodontically treated teeth (Group A), fiber posts were cemented with Excite DSC in combination with Variolink II (Ivoclar-Vivadent). In 15 roots RelyX Unicem (3M-ESPE) was used for fiber post luting (Group B). Within each group, the bond strength of cemented fiber posts was assessed with the trimming and non-trimming microtensile technique, as well as with the push-out test. The great number of premature failures (16.9% in Group A, 27.5% in Group B) and the finding of high standard deviation values make questionable the reliability of the trimming microtensile technique. With the non-trimming microtensile technique, only five sticks were obtained from a total of six roots. The remaining specimens failed prematurely during the cutting phase. With the push-out test no premature failure occurred, the variability of the data distribution was acceptable, and regional differences in bond strength among root levels could be assessed. Relatively low values of bond strength were, in general, recorded for luted fiber posts. In conclusion, when measuring the bond strength of luted fiber posts, the push-out test appears to be more dependable than the microtensile technique.

Dental Bonding↗
PubMed2004

Principles, techniques, and limitations of near infrared spectroscopy.

In the last decade the study of the human brain and muscle energetics underwent a radical change, thanks to the progressive introduction of noninvasive techniques, including near-infrared (NIR) spectroscopy (NIRS). This review summarizes the most recent literature about the principles, techniques, advantages, limitations, and applications of NIRS in exercise physiology and neuroscience. The main NIRS instrumentations and measurable parameters will be reported. NIR light (700-1000 m) penetrates superficial layers (skin, subcutaneous fat, skull, etc.) and is either absorbed by chromophores (oxy- and deoxyhemoglobin and myoglobin) or scattered within the tissue. NIRS is a noninvasive and relatively low-cost optical technique that is becoming a widely used instrument for measuring tissue O2 saturation, changes in hemoglobin volume and, indirectly, brain/muscle blood flow and muscle O2 consumption. Tissue O2 saturation represents a dynamic balance between O2 supply and O2 consumption in the small vessels such as the capillary, arteriolar, and venular bed. The possibility of measuring the cortical activation in response to different stimuli, and the changes in the cortical cytochrome oxidase redox state upon O2 delivery changes, will also be mentioned.

Blood Volume↗
PubMed2004

Bonding to worn or fractured incisal edges: shear bond strength of new adhesive systems.

OBJECTIVES: Resin composites can be proposed for the restoration of incisal edges. If a progressive wear or an old fracture is responsible for the loss of the incisal edge, the bonding substrate is likely to be sclerotic dentin, surrounded by enamel. The purpose of the study was to measure under laboratory conditions, the shear bond strength of three adhesive systems to the enamel and dentin exposed on the edge of incisors as a result of a long-time wear or an old fracture. METHOD AND MATERIALS: Thirty extracted human incisors were selected. The teeth had to exhibit some exposed dentin on their edges, a result of old fractures or wear. The 30 specimens were randomly divided into three groups. In each group, a different adhesive system was tested for the ability to efficiently bond a resin composite restoration to the dental substrate. A three-step system (Scotchbond Multipurpose Plus), a one-bottle adhesive (Scotchbond 1), and a self-etching adhesive (Prompt-L-Pop) were compared. The shear bond strength of the restored samples was measured under a loading machine. The pattern of failure that each sample underwent as a result of loading was assessed under a stereomicroscope. RESULTS: The highest values of bond strength were yielded by Scotchbond Multipurpose Plus (28.14 MPa), followed by Scotchbond 1 (16.15 MPa), and Prompt-L-Pop (9.26 MPa). These differences were statistically significant (P < .05). The most frequent pattern of failure was the combined adhesive-cohesive in resin fracture. CONCLUSION: Adhesive systems involving phosphoric acid etching of the substrate were more dependable than a self-etch adhesive when bonding a resin composite restoration to worn or fractured incisal edges.

Acid Etching, Dental↗
PubMed2004

Clinical trial evaluating the peroxide concentration response of whitening strips over 28 days.

PURPOSE: The research evaluated the peroxide concentration whitening response following self-directed use of whitening strips over a 28-day period. METHODS: A randomized, double-blind, parallel group clinical study was conducted. 37 healthy adult volunteers were randomly assigned to one of three groups based on tooth color at screening: 1.8% hydrogen peroxide strips (HPS), 3.3% HPS or 5.3% HPS. Subjects applied the assigned maxillary strips twice per day for 30 minutes over 28 days. Tooth color was evaluated at day 7, 14 and 28 from digital images of the maxillary six anterior teeth using a standard method. Treatments were compared using analysis of covariance (adjusting for baseline) at a 0.05 level of significance. RESULTS: Hydrogen peroxide at concentrations ranging from 1.8-5.3% resulted in significant (P< 0.05) color improvement versus baseline as early as Day 7. There was a concentration-response for reduction in yellowness (deltab*) and lightness improvement (deltaL*) at all timepoints, favoring the higher concentrations. While the concentration-whitening relationship approached a linear response at Day 7, continued treatment resulted in incremental color improvement. All three peroxide concentrations were well tolerated, and no subjects discontinued early due to a treatment-related adverse event.

Adult↗
PubMed2004

Microtensile bond strength of self-etching adhesives to enamel and dentin.

PURPOSE: To measure the microtensile bond strength to enamel and dentin of three self-etching adhesives in comparison with a total-etch two-step system as a control. MATERIALS AND METHODS: A total of 40 extracted human molars were stored in saline solution until use, then divided into 4 groups of 10 teeth (one group per adhesive system). Half of each of these groups underwent bond strength tests on enamel, and the other half was used for adhesion testing on dentin. The following experimental groups (n = 5) were then formed: E(1) Adper Prompt-L-Pop (AP, 3M ESPE) on enamel; E(2) Xeno CF II (X, Sanking Kogyo) on enamel; E(3) AdheSE (AS, Ivoclar-Vivadent) on enamel; E(4) Excite (EX, Ivoclar-Vivadent) on enamel; D(1) AP on dentin; D(2): X on dentin; D(3) AS on dentin; D(4) EX on dentin. Each tooth yielded 15 to 20 sticks about 0.9 x 0.9 mm in cross-sectional area for microtensile testing. Specimens were loaded in tension at a crosshead speed of 0.5 mm/minute, and bond strength at failure was calculated in MPa. A two-way ANOVA was applied to test for significance of the differences among the groups. RESULTS: The bond strength values of Excite (the control) were significantly higher than those of the test products on enamel (42.92+/-4.8 MPa) and on dentin (45.80+/-5.79 MPa). The self-etching adhesives AdheSE (28.48+/-4.71 MPa) and Xeno CF II (27.22+/-2.74 MPa) revealed significantly stronger adhesion than Adper Prompt-L-Pop (20.16+/-2.07 MPa) on dentin. On enamel, all self-etching test materials performed similarly. The substrate did not appear to have a significant influence on adhesion, as each material reached comparable levels of bond strength on enamel and dentin. CONCLUSION: On both substrates the self-etching adhesives tested performed significantly worse than did the total-etch system.

Acrylic Resins↗
PubMed2003

Muscle oxygenation and pulmonary gas exchange kinetics during cycling exercise on-transitions in humans.

Near-infrared spectroscopy (NIRS) was utilized to gain insights into the kinetics of oxidative metabolism during exercise transitions. Ten untrained young men were tested on a cycle ergometer during transitions from unloaded pedaling to 5 min of constant-load exercise below ( VT) the ventilatory threshold. Vastus lateralis oxygenation was determined by NIRS, and pulmonary O2 uptake (Vo --> Vo2) was determined breath-by-breath. Changes in deoxygenated hemoglobin + myoglobin concentration Delta[deoxy(Hb + Mb)] were taken as a muscle oxygenation index. At the transition, [Delta[deoxy(Hb + Mb)]] was unmodified [time delay (TD)] for 8.9 +/- 0.5 s at VT (both significantly different from 0) and then increased, following a monoexponential function [time constant (tau) = 8.5 +/- 0.9 s for VT]. For >VT a slow component of Delta[deoxy(Hb + Mb)] on-kinetics was observed in 9 of 10 subjects after 75.0 +/- 14.0 s of exercise. A significant correlation was described between the mean response time (MRT = TD + tau) of the primary component of Delta[deoxy(Hb + Mb)] on-kinetics and the tau of the primary component of the pulmonary Vo2 on-kinetics. The constant muscle oxygenation during the initial phase of the on-transition indicates a tight coupling between increases in O2 delivery and O2 utilization. The lack of a drop in muscle oxygenation at the transition suggests adequacy of O2 availability in relation to needs.

Adult↗
PubMed2003

Marginal integrity of ceramic inlays luted with a self-curing resin system.

OBJECTIVE: Aim of this study was to observe the efficacy of two different composite cements on the prevention of marginal deterioration around adhesive ceramic inlay restorations, under laboratory conditions, and to test the null hypothesis that different luting procedures cannot affect sealing ability of luted inlays. METHODS: Twenty-six standardized mesio-occlusal Class II cavities were prepared in extracted posterior teeth. Class II inlays were fabricated with IPS Empress II system following the manufacturer's instructions. The samples were divided into two groups of 13 teeth each at random. Group 1: The ceramic inlays of Group 1 were luted using Excite DSC and an experimental self-curing resin cement (Multilink, Vivadent); in this group, Excite DSC was self-activated and not light-cured. Group 2: Excite DSC in combination with a dual-curing resin cement (Variolink II, Vivadent) was used (as control). In this group Excite DSC was light-cured for 20s separately, before resin cement application. The 'wet' bonding technique was followed. Three samples of each group were selected at random for SEM observations, while the other 10 samples were processed for marginal leakage. The bonding mechanism to dentin and resin cement thickness was evaluated. RESULTS: Samples of both groups showed resin tag and adhesive lateral branch formation. In Group 1 the hybrid layer was mainly uniform along the interface between dental substrates and adhesive material, and resin cement thickness was between 20 and 85 microm. At the cervical margin no gap was detected. In Group 2 the cement thickness was between 30 and 110 microm and hybrid layer formation was observed along the interface but at the cervical margin it was not always uniform and continuous. Resin tag formation was uniform in both groups. At cervical margins, 80% of Group 1 samples showed a perfect seal at the dentin-cementum margins, and 90% at enamel margins. Group 2 samples showed only 50% of cervical margins free from leakage and 80% at the occlusal enamel margins. Statistically significant differences were found at cervical margins between the two groups, while no significant differences were found at enamel site. CONCLUSIONS: It can be concluded that the self-curing adhesive-resin cement combination can properly seal Class II porcelain inlays.

Dental Bonding↗
PubMed2003

Interleukin-8 production induced by the endozepine triakontatetraneuropeptide in human neutrophils: role of calcium and pharmacological investigation of signal transduction pathways.

The endozepine triakontatetraneuropeptide (TTN) induces intracellular calcium ([Ca(2+)](i)) changes and is chemotactic for human neutrophils (PMNs). Because interleukin-8 (IL-8) production is Ca(2+) dependent and can be induced by chemotactic stimuli, we have investigated the ability of TTN to induce IL-8 production in PMNs, as well as the signal transduction mechanisms involved. Our results show that TTN increases IL-8 release and IL-8 mRNA expression in a concentration- and time-dependent fashion, and these effects are prevented by the Ca(2+) chelator BAPTA-AM. TTN-induced [Ca(2+)](i) changes and IL-8 mRNA expression are sensitive to pertussis toxin, to the phospholipase C (PLC) inhibitor U73122 (but not to its inactive analogue U73343) and to the protein kinase C (PKC) inhibitor calphostin C. It is therefore suggested that TTN-induced IL-8 production in human PMNs results from a G protein-operated, PLC-activated [Ca(2+)](i) rise, and PKC contributes to this effect. These findings further support the possible role of TTN in the modulation of the inflammatory processes.

Calcium↗
PubMed2003

Dopaminergic modulation of apoptosis in human peripheral blood mononuclear cells: possible relevance for Parkinson's disease.

Dopamine (DA) modulates apoptosis in neuronal and non-neuronal cells, and dopaminergic pathways contribute to neurodegenerative disease. Human lymphocytes express dopaminergic receptors and DA transporters, and synthesize endogenous catecholamines, which may modulate apoptosis in these cells. In the present study, dopaminergic modulation of apoptosis was investigated in human peripheral blood mononuclear cells (PBMCs) obtained from healthy donors. Twenty-four-hour DA reduced at 0.1-5 x 3 10(-6) M and enhanced at 1-5 x 310(-4) M spontaneous apoptosis. DA 1 x 310(-6) M was inhibited by the D1-like receptor antagonist SCH 23390 1 x 310(-6) M, but not by the D2-like receptor antagonists domperidone 1 x 3 10(-6) M or haloperidol 1 x 3 10(-6) M, while the effect of DA 5 x 3 10(-4) M was prevented by the antioxidants glutathione 5-10 mM or N-acetyl-l-cysteine 1-10 mM. Intracellular reactive oxygen species were respectively reduced and increased by 1-3 h incubation with DA 0.1-10 x 3 10(-6) M and 1-5x310(-4) M. Twenty-four-hour DA 1 x 3 10(-6) M or 5 x 3 10(-4) M had no effect on PBMC expression of Cu/Zn superoxide dismutase or Bcl-2; however, DA 5 x 3 10(-4) M decreased caspase-3 activity. In human PBMCs, DA seems to promote apoptosis through oxidative mechanisms but may also result in cell rescue from apoptotic death possibly through activation of D1-like receptors. The dual effect of DA on human PBMCs closely resembles that on striatal neurons. Lymphocytes of patients with Parkinson's disease may show reduced DA content and impaired DA transporter immunoreactivity. Human PBMCs may thus represent a simple and readily accessible model to study DA-related mechanisms relevant for neurodegenerative disease.

Apoptosis↗