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Biomedical subjects

E Fernandez

Publications and source records attributed to E Fernandez.

At least 19 recordsLinked to original sources
PubMed1992

Antinociceptive effects of Ca2+ channel blockers.

The antinociceptive action of four Ca2+ channel blockers, nifedipine, nimodipine, verapamil and diltiazem, was evaluated and compared to that of morphine using three algesiometric tests in mice and rats, namely, formalin, writhing and modified hot-plate test. Dose-response curves for all the drugs tested were similar and a significant dose-dependent antinociceptive action was evident in the formalin and writhing tests. However, in the hot-plate test, only nimodipine exhibited a significant analgesic effect, confirming the misleading results previously reported for this test. The findings suggest a pharmacological role of Ca2+ channel blockers in the modulation of antinociception under acute conditions. The analgesic action of Ca2+ channel blockers could be mediated by an increase in the nociceptive threshold resulting from interference with Ca2+ influx at opioid receptors, because Ca2+ influx is critical for the release of neurotransmitters and other substances implicated in nociception and inflammation. It is suggested that if a substance has a Ca2+ channel blocking effect, it should probably have some antinociceptive properties.

Analgesics↗
PubMed1992

Effect of ethanol on the Na(+)- and the Na+,K(+)-ATPase activities of basolateral plasma membranes of kidney proximal tubular cells.

The Na(+)- and the Na+,K(+)-ATPase activities of basolateral plasma membranes from rat kidney proximal tubular cells were affected differentially by ethanol. Moreover, at concentrations of ethanol that can be reached in vivo in the blood plasma (50 mM) there was a significant effect on the Na(+)-ATPase activity and practically no effect on the Na+,K(+)-ATPase activity.

Adenosine Triphosphatases↗
PubMed1992

Giant axonal neuropathy: report on a case with focal fiber loss.

We report on a 5 1/2 year-old boy with chronic progressive polyneuropathy, ataxia, and pyramidal signs. His hair was not curled. Sural nerve biopsy disclosed many axons enlarged by accumulation of 10-nm neurofilaments and a marked variability in the number of myelinated fibers as well as in the amount of axonal enlargements among different fascicles. These findings and the electrophysiological data were consistent with a giant axonal polyneuropathy with a multifocal fiber loss.

Axons↗
PubMed1992

Tris discriminates between the different alpha-glucosidase activities from extracts of human neutrophils.

In an attempt to detect acid maltase deficiency in neutrophils from patients with type II glycogenosis, without interference from the 'renal' alpha-glucosidase activity present in these cells, we have evaluated the contribution of the renal component in the total activity measured at pH 4.0 in extracts of human neutrophils. The renal contribution is about 13-25% and renal glucosidase appears to be closely related to the enzyme present on the epithelium of small intestine, which is known to be inhibited by Tris. We have used this compound as a selective inhibitor of the renal component of alpha-glucosidase activity measured at pH 4.0 in total extracts of neutrophils. Our results demonstrate that 0.1 mol/L Tris is an inhibitor of the renal alpha-glucosidase present in neutrophils and can be used to reduce the interference from this enzyme in assays of acid maltase.

Glycoside Hydrolase Inhibitors↗
PubMed1992

Sensory and affective components of pain: separation and synthesis.

It has become increasingly accepted that pain is not simply a sensation generated by nociceptors, but a perceptual phenomenon with particular emotional qualities. The purpose of this article is to bring together vastly different streams of research on the divisibility of pain into sensory and affective components. Empirical evidence for this divisibility is drawn from recent studies using multivariate statistics, signal detection theory, and unidimensional scaling. An important conclusion is that separable though pain components may be, they are not necessarily independent. In critiquing previous research, new criteria are derived for partitioning pain into sensory and affective components. Finally, speculations are offered as to how these same components might be synthesized on the basis of theories of perceptual organization.

Affective Symptoms↗
PubMed1992

Epidemiology of prostatic disorders in the city of Barcelona.

Although disorders of the prostate are among the most prevalent problems in elderly males, little is known about their epidemiological characteristics. The 1986 Barcelona Health Interview Survey (BHIS), a cross-sectional study of a random sample of the noninstitutionalized population of the city, was used to estimate the prevalence of prostatic disorders (PD) and to analyse sociodemographic characteristics, self-perceived health, and use of health services among males reporting PD. Ninety-eight out of 1218 males over 45 years old (8%) reported having PD, the prevalence increasing substantially with age. A pattern of increasing prevalence with decreasing occupational class was found. As compared to subjects not reporting PD, individuals reporting PD reported slightly more restricted activity days (prevalence odds ratio [POR] = 1.28; 95% confidence interval [CI]: 0.52-2.80), more chronic disorders (POR = 4.75; 95% CI: 2.04-13.53), and worse self-perceived health (POR = 1.55; 95% CI: 0.92-2.58). Medical visits and hospitalizations were also higher in the prostatic group (P < 0.05). Men reporting PD appear to constitute a subgroup with increased morbidity and health services use.

Age Factors↗
PubMed1992

Role of tissue hypoxia as the mechanism of lactic acidosis during E. coli endotoxemia.

We compared the hemodynamic and metabolic alterations produced in rabbits by similar decreases in cardiac output created by inflating a balloon placed in the right ventricle (n = 6) with those produced by an intravenous bolus of Escherichia coli lipopolysaccharide (LPS; SEP group; n = 6). We measured O2 consumption (VO2), O2 transport (TO2), and O2 extraction ratio (ERO2) for the whole animal and also for the left hindlimb. Both groups experienced similar decreases in cardiac output, systemic TO2, and VO2 and similar increases in ERO2. For the hindlimb, TO2 was similar, but VO2 and ERO2 were lower for the SEP group 30 min after LPS administration (P less than 0.05); however, this difference disappeared during the remainder of the experiment. Arterial lactate concentration was greater (P less than 0.05) for the SEP group. There were no differences in skeletal muscle PO2, measured with a multiwire surface electrode, or in cardiac and skeletal muscle concentrations of high-energy phosphates. We hypothesize that a direct effect of LPS on cellular metabolism may have resulted in greater arterial lactate concentration for the SEP group.

Acidosis, Lactic↗
PubMed1992

Reconstruction of peripheral nerves: the phenomenon of bilateral reinnervation of muscles originally innervated by unilateral motoneurons.

It is well known that after reconstruction of sectioned peripheral nerves in adult mammals, denervated muscles are reinnervated by the axotomized motoneurons lying in the original motonucleus. It is less well known that these muscles can also be reinnervated by uninjured motoneurons lying in the homologous contralateral motonucleus. Therefore, after nerve reconstruction, bilateral motoneuron reinnervation of muscles can occur. Contralateral motoneurons sprout axons that cross the midline, grow in the reconstructed nerve, and reach muscle targets. This phenomenon was observed after reconstruction of several different peripheral nerves in adult mammals, including the oculomotor nerve in guinea pigs and the facial and sciatic nerves in rats. The retrograde axonal transport of horseradish peroxidase was used for the study of the organization of the brainstem and spinal cord motonuclei. Horseradish peroxidase was injected into the medial rectus muscle, the stylohyoid muscle, and the trunk of the sciatic nerve. The distance between the homologous motonuclei of both sides influenced the occurrence of this phenomenon. In fact, bilateral reinnervation of muscles after nerve reconstruction was found in 36% (sciatic nerve), 50% (facial nerve), and 100% (oculomotor nerve) of the operated animals. The total number of contralateral motoneurons found were 14% (oculomotor nerve), 8% (facial nerve), and 5% (sciatic nerve). Bilateral reinnervation of muscles was evoked by both immediate and delayed peripheral nerve repair and was a stable phenomenon, seen between 3 and 21 months after facial nerve reconstruction.

Animals↗
PubMed1992

Cholinergic receptors in the human vas deferens.

This study represents the first investigation demonstrating the contractile response to exogenous acetylcholine (ACh) in the isolated human vas deferens. Pharmacological characterization of cholinergic receptors was achieved using selective antagonists to define receptor subtypes. In the HVD the effect of exogenous ACh is revealed as a dose-dependent sudden increase in the basal tension of the vasa. The ACh receptors of the HVD were competitively antagonized by atropine (ATR) with a high pA2 value (8.78). The main finding of this study is the presence of cholinergic receptors of the pharmacologically defined M1-ACh subtype in the isolated HVD, according to the pA2 values obtained with pirenzepine (PRZ) 7.39, AF-DX 116 (AF) 5.92 and 4-DAMP 5.65, M1-ACh, M2-ACh and M3-ACh selective antagonists, respectively. Prazosin (PZ), a selective alpha 1-adrenergic antagonist, displayed a similar competitive antagonism for the contractile response evoked both by ACh (pA2 = 8.69) and NE (pA2 = 8.58) in the HVD. The antagonism exerted by PZ on the ACh-induced contractile response of the HVD, suggests that ACh probably acts at a presynaptic level stimulating the release of NE from an adrenergic neuron. According to these findings, the receptor involved in this action, located in the proximity of the nerve terminals, seems to be of the M1-ACh subtype.

Acetylcholine↗
PubMed1992

Experimental repair of the oculomotor nerve: the anatomical paradigms of functional regeneration.

In adult guinea pigs, the oculomotor nerve was sectioned proximally (at the tentorial edge) or more distally (at the orbital fissure) and immediately repaired by reapproximation. During a 24-week postoperative period, extrinsic eye motility was assessed by analyzing the vestibulo-ocular reflexes. The regenerated oculomotor nerve was studied morphometrically on semi-thin histological sections at 16 and 24 weeks postinjury. The selectivity of muscle reinnervation was investigated by injection of both single (horseradish peroxidase) and double (fluorescent dyes) retrograde axonal tracers into the eye muscles. Following proximal repair of the oculomotor nerve, the degree of recovery of extraocular motility varied among different animals and remained stable over long-term observations. In animals with poor recovery, aberrant eye movements were always found, and the somatotopic map of the reinnervated eye muscles was greatly altered. Distortions of the central representation were also seen in those animals in which a good level of functional recovery was seen. However, in animals with good recovery, a topographic bias was re-established by about 65% of the original neuronal population, as opposed to 26% in the animals with poor recovery. Neurons located contralateral to the axotomized nucleus sprouted intra-axially and projected their axons to denervated eye muscles. The number and diameter of the regenerated axons, the number and soma diameter of the axotomized neurons, and the ratio of distal axonal branches to proximal supporting neurons were all related to the degree of functional recovery. Following repair of the oculomotor nerve at the orbital fissure, extraocular motility had recovered in all of the animals at 16 weeks without aberrant phenomena. Functional regeneration of the distally transected oculomotor nerve is thought to be the result of selective muscle reinnervation.

Animals↗
PubMed1992

Levocarnitine acetyl prevents cell death following long-term section of the vagus nerve in rats.

Levocarnitine acetyl has previously been found to significantly prevent axotomy-induced cell death in the spinal cord motor nucleus 9 and 12 months after section of the sciatic nerve in rats. In the present paper, the effects of levocarnitine acetyl on axotomy-induced cell death in the brain stem motor nuclei 90 days after section of the vagus nerve were studied. The right vagus nerve was cut at the neck. To prevent regeneration, a 5 mm-long segment of the vagus nerve was excised and the distal stump was displaced caudally. After surgery, a group of rats (n = 6) was treated with levocarnitine acetyl dissolved in the drinking water (75 mg/kg/day) (Group I). A second group of operated rats (n = 4) received drinking water alone. (Group II). Ninety days postoperatively, in the rats of both groups the proximal nerve stump of the vagus nerve was injected with horseradish peroxidase to label retrogradely the brain stem motoneurons of the dorsal motor vagal and the ambiguus nuclei. The brain stem nuclei were also labelled by horseradish peroxidase in three unoperated control rats (Group III). In the Group II rats, the number of horseradish peroxidase-labelled motoneurons of the dorsal motor vagal nucleus was found to be significantly smaller than in either the Group I (p < 0.01) or the Group III (p < 0.02) animals. In the Group I rats, the number of motoneurons of the dorsal motor vagal nucleus was not significantly smaller compared to the Group III rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcarnitine↗
PubMed1992

Indications and results of hepaticojejunostomy in benign strictures of the biliary tract.

The postoperative and late results of 99 patients with benign strictures of the biliary tract are presented. Patients were classified according to Bismuth into 24 cases with lesion type I, 36 cases with type II, 35 cases with type III and 4 patients with type IV. All were submitted to hepaticojejunostomy with a long Roux-en-Y loop. The etiology of the strictures varied according to the type of stricture. In patients of type I, inflammatory and iatrogenic causes were observed. Among type II and III patients, previous cholecytocholedochal fistulas were the main cause, together with accidental section or ligature of the common bile duct. Operative mortality was absent in strictures of types I and II, while it was around 25% in cases of types III and IV. At late control, the best results were seen among patients with strictures of types I and II. We believe that the main factor determining the early and late outcome of these cases with benign strictures is the location of the stricture and the quality of the proximal duct.

Adult↗
PubMed1992

alpha-Glucosidase and N-acetyl-beta-D-glucosaminidase isoenzymes in serum.

Using different conditions for incubation and fluorometry with 4-methylumbelliferylglycosides as substrates, we demonstrated the presence of acid alpha-glucosidase, "renal" alpha-glucosidase, N-acetyl-beta-D-glucosaminidase A, and N-acetyl-beta-D-glucosaminidase B in freshly drawn normal human serum. The acid alpha-glucosidase enzymatic activity was determined at pH 4.0 in 0.1 mol/L Tris reagent, whereas the renal isoenzyme activity was determined at pH 5.6 in presence of 0.05 mol/L turanose reagent. N-Acetyl-beta-D-glucosaminidases A and B were determined by their different behaviors on heating. The corresponding reference intervals for each enzyme were calculated from results for 40 controls: acid alpha-glucosidase (0.024 +/- 0.010 U/L), renal alpha-glucosidase (0.035 +/- 0.012 U/L), N-acetyl-beta-D-glucosaminidase A (10.2 +/- 2.9 U/L), and N-acetyl-beta-D-glucosaminidase B (4.4 +/- 2.1 U/L).

Acetylglucosaminidase↗
PubMed1979

Outpatient oxygen therapy in chronic obstructive pulmonary disease. A review of 13 years' experience and an evaluation of modes of therapy.

Thirteen years' experience with home oxygen for patients with advanced chronic obstructive pulmonary disease are reviewed. Home oxygen is safe and relieves pulmonary hypertension and elevated RBC mass in some, but not all patients. Marked clinical improvement is the most important result of long-term home oxygen use, including reduced hospitalizations and return to gainful employment for a few patients. Chronic compensated carbon dioxide retention is well tolerated and adaptive in cases of severe chronic airflow obstruction. New oxygen concentrators are effective in correcting hypoxemia and may make home oxygen administration more convenient and less expensive.

Aged↗
PubMed1977

Time course of ovum transport in guinea pigs.

The time course of ovum transport was determined in cycling guinea pigs. The occurrence of ovulation was determined in assessing changes in vaginal cytology. The day of the postovulatory leukocyte influx was considered day 1 of the cycle. Ovum transport in guinea pigs is characterized by a relatively long sojourn in the ampulla, followed by rapid transport through the isthmus. This pattern is similar to that seen in women and subhuman primates and different from the pattern in rabbits.

Animals↗