Biomedical subjects

M A Mendiola

Publications and source records attributed to M A Mendiola.

4 recordsLinked to original sources

PubMed2001

Hypoxia regulates avian cardiac Arnt and HIF-1alpha mRNA expression.

The aryl hydrocarbon receptor nuclear translocator (Arnt) and hypoxia-inducible factor (HIF)-1alpha mediate cellular responses to hypoxia. We investigated the ability of hypoxia to regulate Arnt and HIF-1alpha mRNA in the heart in vivo. We cloned avian Arnt, developed an in vivo model of chronic cardiac hypoxia, and measured expression of cardiac Arnt and HIF-1alpha mRNA by quantitative RT-PCR. Chronic hypoxic exposure (24 h to 15% O(2)) of day 9 chick embryos resulted in a 30-fold increase in covalent binding of (3)H-misonidazole, a hypoxic tissue marker, to cardiac tissue, and a 2-fold induction of cardiac inducible nitric oxide synthase mRNA, compared to normoxic controls. In this same model, cardiac Arnt mRNA expression decreased by 35%, while HIF-1alpha mRNA expression increased 400%. These data suggest that regulation of Arnt and HIF-1alpha mRNA expression may contribute to the physiological responses of the heart during prolonged hypoxia.

Amino Acid Sequence↗

PubMed1999

Thiohydrazone copper(II) complexes. The relationship between redox properties and superoxide dismutase mimetic activity.

The redox behaviour of copper(II) complexes with the open chain ligand, benzilbisthiosemicarbazone, and the macrocyclic one [3,4,10,11-tetraphenyl-1,2,5,8,9,12,13-octaazacyclotetradeca-7,14- dithione- 2,4,9,11-tetraene] has been explored by cyclic voltammetry. The half-wave potential values for the copper(II)/copper(I) redox couple and the spectral data obtained on dimethylsulfoxide (DMSO) solution agree with the superoxide dismutase (SOD)-mimetic activity of the complexes. The macrocyclic complexes show more positive reduction potential and more activity than the open chain derivatives. From our results it follows that the structure and conformation of ligand has influence on the redox potential of central atom in coordination compound. The changes in the coordination sphere are connected with the change of biological function of compounds represented by SOD-mimic activity. In addition, the L1H6 derivatives show quasireversible waves associated to Cu(II)/Cu(III) process.

Binding Sites↗

PubMed1999

[Ropivacaine].

This paper describes the pharmacological, pharmacokinetic and pharmacodynamic features of ropivacaine on both an experimental and clinical level. Ropivacaine is an amide-type local anesthetic whose chemical structure is related to that of mepivacaine and bupivacaine and whose duration of effect falls between the two. Ropivacaine is a less potent effector of motor blockade than bupivacaine, and its toxic effects on the central nervous system and myocardial tissue is likewise less. Ropivacaine has been employed for epidural anesthesia and analgesia (including through a caudal approach), for peripheral motor blockade, for local infiltration (in gel form), and for intravenous regional anesthesia in ophthalmologic surgery involving peri- and retrobulbar blockade. Subarachnoid use has not yet been accepted in Spain, although phase IV clinical trials of this application have begun. Concentrations of 2 mg/ml (0.2%) and 7.5 mg/ml (0.75%) and 10 mg/ml (1%) are available in Spain.

Amides↗

PubMedDate not supplied

[Transient neurological syndrome after spinal hyperbaric bupivacaine: a new case].

A 47-year-old woman underwent hysteroscopy and removal of an endometrial polyp because of irregular, acyclic bleeding of 6 months' duration. The procedure was carried out under spinal anesthesia. No adverse events occurred during puncture or surgery, or in the immediate postoperative recovery period. Recovery from the sensory and motor block was normal. Twenty-four hours after surgery gluteal and lower limb pain and paresthesia developed, with no sensory or motor deficit. The symptoms suggested transient neurological syndrome. This syndrome has been defined by pain in the lower limbs, buttocks, thighs and calves after uncomplicated spinal anesthesia and full recovery from the sensorimotor block during the immediate postoperative period (first 24 hours). The condition is self-limiting and does not leave permanent neurological sequelae. Recent studies have demonstrated biochemical and anatomical changes that provide a structural basis for this clinical entity. According to this literature, transient neurological syndrome might be a mild expression of local anesthetic toxicity. Recent findings show that the initial injury to the nerve cell membrane, induced by high concentrations of local anesthetic could lead to permanent neuronal damage.

Anesthesia, Spinal↗