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Biomedical subjects

Antonio Baldi

Publications and source records attributed to Antonio Baldi.

7 recordsLinked to original sources
PubMed2006

Endocannabinoids in chronic migraine: CSF findings suggest a system failure.

Based on experimental evidence of the antinociceptive action of endocannabinoids and their role in the modulation of trigeminovascular system activation, we hypothesized that the endocannabinoid system may be dysfunctional in chronic migraine (CM). We examined whether the concentrations of N-arachidonoylethanolamide (anandamide, AEA), palmitoylethanolamide (PEA), and 2-arachidonoylglycerol (2-AG) in the CSF of patients with CM and with probable CM and probable analgesic-overuse headache (PCM+PAOH) are altered compared with control subjects. The above endocannabinoids were measured by high-performance liquid chromatography (HPLC), and quantified by isotope dilution gas-chromatography/mass-spectrometry. Calcitonin gene-related peptide (CGRP) levels were also determined by RIA method and the end products of nitric oxide (NO), the nitrites, by HPLC. CSF concentrations of AEA were significantly lower and those of PEA slightly but significantly higher both in patients with CM and PCM+PAOH than in nonmigraineur controls (p<0.01 and p<0.02, respectively). A negative correlation was found between AEA and CGRP levels in CM and PCM+PAOH patients (r=0.59, p<0.01 and r=-0.65, p<0.007; respectively). A similar trend was observed between this endocannabinoid and nitrite levels. Reduced levels of AEA in the CSF of CM and PCM+PAOH patients may reflect an impairment of the endocannabinoid system in these patients, which may contribute to chronic head pain and seem to be related to increased CGRP and NO production. These findings support the potential role of the cannabinoid (CB)1 receptor as a possible therapeutic target in CM.

Adult↗
PubMed2006

A hydrogel-based implantable micromachined transponder for wireless glucose measurement.

In this paper, we report on the design and characterization of a new hydrogel-based implantable wireless glucose sensor. The basic device structure is a passive [inductor/capacitor (LC)] micromachined resonator coupled to a stimuli-sensitive hydrogel, which is confined between a stiff nanoporous membrane and a thin glass diaphragm. As glucose molecules pass through the nanoporous membrane, the hydrogel swells and deflects the flexible glass diaphragm, which is the movable plate of the variable capacitor in the totally integrated passive LC resonator. The corresponding change in resonant frequency can be remotely detected. A glucose- sensitive phenylboronic acid-based hydrogel was loaded into the microtransponder, and its sensitivity and time response were measured. Prior to hydrogel loading, the sensitivity of the pressure sensor to applied air pressure was measured to be -222 kHz/kPa over the frequency range 51-->42 MHz. The sensor showed a sensitivity of -34.3 kHz/mM over the glucose concentration range 0-20 mM (at pH 7.4), and a response time of 90 min. The dynamic response, although unacceptable at such values, can be easily improved by decreasing the hydrogel thickness and reducing the sensor and porous membrane thicknesses. The transponder's overall dimensions were 5x5x0.8 mm3, small enough for subcutaneous implantation.

Biosensing Techniques↗
PubMed2006

Proinflammatory cytokines, adhesion molecules, and lymphocyte integrin expression in the internal jugular blood of migraine patients without aura assessed ictally.

OBJECTIVE: The aim of the present research was to verify the levels of the soluble adhesion molecules sL- and sE-selectins, intercellular adhesion molecule (sICAM)-1, and vascular cell adhesion molecule-1 in serial samples of internal jugular venous blood taken from migraine patients without aura (MWoA) during attacks. The expression of leukocyte function antigen (LFA)-1 and very late activation antigen (VLA)-4 was also assessed on lymphocytes obtained from jugular venous blood. Levels of certain proinflammatory cytokines (tumor necrosis factor-alpha[TNF-alpha], interleukin-1beta[IL-1beta], IL-4, and IL-6) were also determined and correlated with those of adhesion molecules. PATIENTS AND METHODS: Seven MWoA patients were admitted in the hospital during attacks and blood samples were taken immediately after catheter insertion, at 1, 2, and 4 hours after attack onset, and within 2 hours after its termination. The levels of adhesion molecules and cytokines were measured with ELISA method. The expression of LFA-1 and VLA-4 was assessed by flow cytometry. RESULTS: A parallel transient increase of sICAM-1, TNF-alpha, and IL-6 was observed in the first 2 hours after attack onset compared with the time of catheter insertion (P < .0001, <.001, and <.003, respectively). The proportion of CD4+ and CD8+ T-cells expressing high levels of LFA-1 showed instead a progressive down-regulation with significantly lower percentages at 2 and 4 hours after attack onset (P < .01 and <.022, respectively). No variation in the percentage of VLA-4 expressing cells was observed at any time of the study. CONCLUSIONS: The transient increase in sICAM-1 and TNF-alpha found in the internal jugular blood of MWoA patients assessed ictally can be induced by sensory neuropeptides released from activated trigeminal endings. The progressive decrease in sICAM-1 levels during attacks and the down-regulation of LFA-1 expression by lymphocytes could antagonize their transvascular migration, supporting the hypothesis of sterile inflammation in the dura mater during migraine attacks.

Cytokines↗
PubMed2005

Application of ICHD 2nd edition criteria for primary headaches with the aid of a computerised, structured medical record for the specialist.

We tested the computerised, structured medical record by entering and analysing the consecutive clinical sheets of primary headaches in the episodic forms (200) and chronic headache (200) and the corresponding output diagnoses of patients attending our Headache Centre. A diagnosis of one of the primary headache forms was obtained in 67.9% of cases. A certain diagnosis of primary headache plus that of a probable form was obtained in 24.4% of cases (12.7% represented by chronic migraine (CM) or chronic tension-type headache (CTTH)+probable medication overuse headache). Only probable forms were diagnosed in the remaining 7.3% (as single probable diagnosis in 5.8% of cases or multiple diagnoses of probable forms in the remaining ones). The percentage of certain diagnoses mainly in the chronic headache group (28.4%), and to a lesser extent tension-type headache (6.5%), were obtained in 34.9% of cases. A certain diagnosis of one chronic form plus that of a probable form was obtained in 50.8% of cases (26.9% represented by probable medication-overuse headache). Only probable forms were diagnosed in 13.46% (as single probable diagnosis in 8.73% of cases or multiple diagnoses of probable forms in the remaining ones). In the other cases, the ICHD-II classification does not allow the diagnoses of CM, CTTH or probable forms and medication overuse headache because the mandatory criteria for the diagnoses are too stringent and do not reflect modifications of the headache pattern in relation to its chronicity. These preliminary results underscore the usefulness of a computerised device based on the ICHD 2nd edition for diagnostic purposes in tertiary centres dedicated to headaches in clinical practice as well as its relevance for research. This computerised device may help to validate the new diagnostic criteria and to answer some emerging questions from the application of the new classification version, the relevance of which should be verified in clinical practice.

Diagnosis, Computer-Assisted↗
PubMed2004

Hard and soft micromachining for BioMEMS: review of techniques and examples of applications in microfluidics and drug delivery.

Recent development in microfabrication (micromachining, microelectromechanical systems, MEMS) permits the integration of hard and soft structures, and enables the design of controllable microfluidic systems, which may be applied to drug delivery. In this paper, we present a tutorial review of both classical "hard" and more recent "soft" micromachining techniques. We then provide examples where these techniques are combined to produce hydrogel-based microfluidic control systems. The most complex of these systems utilizes a very small hydrogel based on phenylboronic acid to control the flow of an insulin solution in response to changes in glucose concentration.

Drug Delivery Systems↗
PubMed2003

Phase unwrapping by region growing.

The phase unwrapping problem consists in mingling out an integer field whose values make the original wrapped phase field continuous. Even if in principle the problem is very simple--a direct integration of the wrapped phase field suffices--in the presence of noise and/or undersampling, the solution is no longer unique and the direct integration methods usually fail to find an acceptable solution. This work presents what is to my knowledge a new unwrapping algorithm that attempts to find the solution by iteratively merging and shifting the continuous areas until a single region is built or no further moves are possible. Unlike the tile methods, the regions can have arbitrary shape and need not be ingle-connected so that, by removing the predefined size and shape constraint, the algorithm is very robust. The greater freedom of the regions' shape makes their handling more problematic, so that certain implementation aspects, critical to algorithm performance, are presented here. Some unwrapping examples are also presented and memory requirements are discussed.

Journal Article↗