Biomedical subjects

M Alvaro

Publications and source records attributed to M Alvaro.

6 recordsLinked to original sources

PubMed2001

First molecular switch encapsulated within the cavities of a zeolite. A dramatic lifetime increase of the charge-separated state.

A [2]-catenane consisting of a bipyridinium cyclophane and a dioxybenzene macrocyclic polyether has been encapsulated within the supercages of zeolite Y by ship-in-a-bottle synthesis; laser flash photolysis reveals that the charge-separated species decays in hundreds of microseconds in contrast to the few picoseconds previously reported for the same transient in acetonitrile.

Journal Article↗

PubMed2001

Laser flash photolysis study of Jacobsen catalyst and related manganese(III) salen complexes. Relevance to catalysis.

The laser flash photolysis and emission properties of a set of five-coordinate manganese(III) Schiff-base complexes have been examined. In contrast to the intramolecular electron transfer between Mn3+ and the equatorial salen ligand reported to occur in the absence of axial coordination, our laser flash photolysis study has shown that the reactivity of the respective excited states is appreciably influenced by the electron donor strength of the apical ligand at the metal center. In fact, homolytic and heterolytic photocleavage of the metal-ligand apical bond can be the most important processes upon laser excitation, their relative contribution being influenced by medium effects and the sigma-charge donation of the axial ligand. On the other hand, the detection of reactive intermediates such as the oxomanganese(V) salen complex (lambda(max) 530 nm) by laser flash photolysis opens the way to apply this fast detection technique to the study of reaction mechanisms in catalysis by metallic complexes. As a matter of fact, quenching of oxomanganese(V) salen by simple alkenes has been observed by laser flash.

Journal Article↗

PubMed1999

Transcutaneous electrostimulation: emerging treatment for diabetic neuropathic pain.

Three independent studies utilizing transcutaneous electrical nerve stimulation to relieve diabetic peripheral neuropathic pain were reviewed. The proprietary equipment, an H-wave machine, administered all electrotherapy. The first two studies assessed the efficacy of electrotherapy alone and electrotherapy with amitriptyline. The treated electrotherapy group reported an overall greater reduction of symptoms, 52% with 2-3 weeks of active treatment. Amitriptyline alone produced a 26% reduction of pain after 4 weeks. The addition of active electrotherapy to amitriptyline produced a 66% reduction of pain. The final study looked at patients who have utilized electrotherapy for over one year. A reported 44% improvement of symptoms was attained with continuous electrotherapy treatment. The data also suggested that a maintenance treatment protocol for long-term pain relief would have to be developed.

Amitriptyline↗

PubMedDate not supplied

Beneficial effects of electrical stimulation on neuropathic symptoms in diabetes patients.

Transcutaneous electrical nerve stimulation is utilized for relieving pain in the diabetes peripheral neuropathy. Previous studies were short-term and did not document sustained beneficial effects. In this study, the authors evaluated long-term effectiveness of electrotherapy administered by proprietary equipment, an H-wave machine. A detailed questionnaire concerning patients' symptoms prior to and following electrotherapy was mailed to the users of H-wave machine. The responses of 34 individuals who had diabetes mellitus were analyzed (age 74.1 +/- 1.6 SEM years, body mass index 28.5 +/- 0.8 kg/m2, duration of diabetes 15.8 +/- 2.0 years and duration of neuropathic symptoms 8.0 +/- 1.8 years). Telephone interviews were conducted with 20 additional diabetes patients selected randomly from the persons who did not return the questionnaire. Forty-one (76%) patients reported a 44.0 +/- 4.0% subjective improvement in their neuropathic pain. The overall improvement in pain was also significant on an analog scale of 10 (p < .01), and correlated well with the percent amelioration data (r2 = .65). These data suggest an effectiveness of electrotherapy in managing neuropathic pain as an adjunct to the analgesics. It appears to provide continued benefit as the responders have used this nonpharmacological treatment modality for an average period of 1.7 +/- 0.3 years.

Aged↗

PubMedDate not supplied

[Adhesion molecules and asthma].

The inflammation markers in asthma can help the prognosis, diagnosis and monitoring of the respiratory illness. The adhesion molecules (AM) are membrane glycoproteins that intervene in the contact between the two cells or between the cell and the extracellular matrix. Their aim is to maintain the contact between two cells for the time that is necessary in order to establish a communication between them and so that the function indicated takes place. The most important functions of the AM's are to facilitate the adhesion of the circulating leukocytes to the vascular endothelium with the posterior transendothelial migration that contribute, by doing so, to the perpetuation of the inflammatory reaction in bronchial asthma. The AM's can act as receptors or as specific ligands for these receptors and are expressed both in leukocytes and endothelial cells as well as in epithelial cells. There are several AM families that allow for these interactions and that collaborate in the specificity of the cellular recognition in the immunologic reaction. The most known are the selectines, the super family of the immunoglobulins and the integrins, that act in a cascading manner. In bronchial asthma, the inflammatory reaction consists of three sequential processes: the recognition-activation phase, the inflammation phase and the solution phase. The AM's act in the second or the inflammation phase. The positive control of the E-selectine, followed by that of the ICAM-1 on the surface of the endothelium cell, leads in sequence to the adhesion, initially of the neutrophils and then the lymphocytes and monocytes, as a response to the antigenic stimulus. The initial loose adhesion of the leukocytes to the vascular endothelium, activated by contact or by cytokines, takes place by means of the selectines. In the microvasculature the strength of the flow pushes the adhered leukocytes, causing the disappearance of the selectine-ligand interactions which form againg quickly in descending direction as the leukocyte moves. The result is the rolling of the spherical leukocyte along the surface of the endothelium. This leukocyte becomes activated and its cytoskeleton is rearranged, and now has a flat shape and the affinity of its integrins is increased by the endothelial ligands. This leukocyte can die within a few days, can activate itself or exit via the lymphatic vessels. The activated monocytes that are located in the extravascular tissues are differentiated from the histiocytes, which are the final cellular effectors of the inflammatory reaction. The importance of the knowledge of the AM structure and the functions, is due to the fact that there is a possible pharmacological action on them. The data obtained from clinical studies, as well as the in vitro results, confirm the importance of the AM modulation as well as therapeutic approach to bronchial asthma.

Antigen Presentation↗

PubMedDate not supplied

Chronic granulomatous disease: six new cases.

We report six new cases of chronic granulomatous disease (CGD) diagnosed at our service. The cases represent 1.1% of all primary immunodeficiencies diagnosed. Four of the children were boys and two were girls. The hereditary mechanism was X-linked in three cases and autosomal recessive in the other three. Clinical manifestations appeared before the age of 2 years in all cases; the illness appeared earlier in males, and was more severe, consisting of bacterial infections such as abscesses in the liver, lungs or skin, suppurating lymphadenitis and mastoiditis. None of the patients had osteomyelitis. The germs isolated were bacteria (Staphylococcus, Salmonella, Serratia, Pseudomonas, Enterococcus) and fungi (Candida, Aspergillus, Trichopyton). Orientative complementary evidence was intense leukocytosis, high levels of acute phase reactants (PCR and VSG), polyclonal hypergammaglobulinemia and high LB ant LT4 levels. Definitive diagnosis was provided by the NBT test and chemiluminescence in all cases.

Adolescent↗