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Biomedical subjects

A Esteban

Publications and source records attributed to A Esteban.

At least 73 records · Page 4Linked to original sources
PubMed1994

Eyelid motor abnormalities in progressive supranuclear palsy.

Eyelid motor abnormalities found in progressive supranuclear palsy are reviewed. Electrophysiological correlates of blepharospasm, levator inhibition (blepharokolysis) and supranuclear paralysis of lid closure are presented. Disorders of eyelid motility are not uncommon in progressive supranuclear palsy (PSP). They may be found in about one third of patients with this syndrome (Jackson et al., 1983; Golbe et al., 1989). This is not surprising since ocular and eyelid movements are highly coordinated, mainly in the vertical plane (Gordon, 1951; Kennard and Smith, 1963; Kennard and Glaser, 1964), and a supranuclear ophthalmoplegia with down gaze impairment is a cardinal feature of PSP (Steele et al., 1964). The spectrum of eyelid motor disorders described in PSP includes blinking abnormalities, lid retraction, blepharospasm, levator inhibition and supranuclear palsy of eye closure.

Blepharospasm↗
PubMed1994

Development of myelopathy before herpes zoster rash in a patient with AIDS.

We describe the case of a patient with AIDS who developed progressive myelopathy due to varicella-zoster virus 2 months before the appearance of skin lesions typical of herpes zoster. Varicella-zoster virus was isolated from his CSF. Therapy with acyclovir failed to control his neurological complications despite its in vitro efficacy against the isolates.

AIDS-Related Opportunistic Infections↗
PubMed1994

Modes of mechanical ventilation and weaning. A national survey of Spanish hospitals. The Spanish Lung Failure Collaborative Group.

Little information exists regarding the proportion of patients treated with mechanical ventilation in intensive care units (ICUs), their underlying disease states, the modes of ventilation used, duration of ventilator support, methods and time required for weaning, and mortality in these patients. We carried out a cross-sectional multicenter study in 47 medical-surgical ICUs in Spain to investigate these issues in 290 patients who required mechanical ventilation for at least 24 hs. Relative frequency of different modes was as follows: assist-control ventilation (AC), 55%; synchronized intermittent mandatory ventilation (SIMV), 26%; pressure support ventilation (PSV), 8%; SIMV plus PSV, 8%; pressure-controlled ventilation (PCV), 1%; and continuous positive airway pressure (CPAP), 2%. Overall duration of mechanical ventilation was 27.1 +/- 1.1 (SE). A variety of techniques were used for weaning: T-tube trials, 24%; SIMV, 18%; PSV, 15%; SIMV plus PSV, 9%; and some combination of two or more methods in succession in 33% of the patients. Time required for weaning using a combination of SIMV and PSV was longer (17.8 days) than with other techniques (about 5 days, p < 0.01). Time between initiation of weaning and removal of mechanical ventilation accounted for 41% of total ventilator time and was particularly high (59%) in patients with chronic obstructive pulmonary disease. Overall mortality rate was 34%, and it was higher in patients who were ventilated for 1 to 10 days than in those ventilated for a longer time. Despite the availability of several new modes of ventilator support, older modes such as AC and SIMV were more commonly used. Weaning constitutes a large portion of total ventilator time, and thus, measures that expedite the weaning process should markedly decrease the duration of mechanical ventilation.

APACHE↗
PubMed1993

Fasciculation-myokymic activity and prolonged nerve conduction block. A physiopathological relationship in radiation-induced brachial plexopathy.

Fourteen radiation-induced brachial plexus neuropathies in 12 patients suffering from cancer were studied. Neurophysiological evaluation showed a diffuse neurogenic lesion with muscular denervation signs associated with motor and sensory nerve conduction impairment of axonal type in the distal segments of the arm. Somatosensory evoked potentials were frequently abnormal, with absence of N9 in 9 out of the 10 extremities explored. The most characteristic findings were, however, the presence of fasciculation potentials--single and grouped--and myokymic discharges in 78.5% of cases (11 out of 14 plexuses), and a motor nerve conduction block on proximal stimulation, at the supraclavicular as well as cervical spine levels, in all of the cases. Both phenomena showed a high correlation when analyzed in the same neuromuscular territory. The 5 muscles with no voluntary activity and complete--or nearly complete--motor nerve conduction block were the ones with the most intense ectopic activities. The conduction blocks were present after long periods of illness in all cases and, in 2 of the cases, they persisted in successive explorations at intervals of 9 months and 2 years respectively. These data would support a probable cause-effect relationship between a persistent and prolonged motor nerve conduction block and the presence of fasciculation-myokymic type activities. One could even postulate that the infrequent neuropathies, in which both findings have been described as relevant features, have a similar physiopathological mechanism.

Action Potentials↗
PubMed1993

Hemodynamic effects of oxygen therapy in patients with acute exacerbations of chronic obstructive pulmonary disease.

The effects of oxygen therapy in patients with stable COPD have been previously reported; however, the hemodynamic changes induced by oxygen therapy in patients during acute exacerbations of COPD are less well known. To investigate the hemodynamic effects of controlled oxygen therapy in patients with acute exacerbations of COPD shortly after arriving at the hospital, we studied 15 consecutive patients who came to the emergency room with acutely decompensated COPD that did not require mechanical ventilation. Patients were monitored with a pulmonary artery catheter and a radial artery catheter. Oxygen uptake was calculated by the modified Fick equation. Arterial and venous blood gas levels and hemodynamic parameters were measured while breathing room air (baseline) and after 30 min on oxygen therapy via face mask. Measurements were repeated after 24 and 48 h. The fractional concentration of oxygen in the inspired gas (FIO2) administered was adjusted to keep the PaO2 above 55 mm Hg. All patients had a PaO2 below 45 mm Hg at the beginning of the study. After 30 min of oxygen therapy, there was a significant (p < 0.05) increase in arterial oxygen saturation (from 62 +/- 16 to 87 +/- 9 percent), mixed-venous oxygen pressure (from 25 +/- 5 to 43 +/- 11 mm Hg), and oxygen delivery (from 11.1 +/- 3.7 to 19.3 +/- 8.9 ml/kg.min). Oxygen uptake did not change significantly (from 4.1 +/- 1.2 to 4.3 +/- 1.6 ml/kg.min). The oxygen extraction ratio decreased from 37.5 +/- 10.1 to 25.3 +/- 9.6 percent. These changes were maintained during the following 48 h. There were no significant changes in cardiac output and systemic vascular resistance. A trend toward lower values of pulmonary vascular resistance did not reach statistical significance. We conclude that oxygen therapy in patients with acute exacerbations of COPD that do not require mechanical ventilation increases oxygen delivery without changes in cardiac output or oxygen uptake.

Acute Disease↗
PubMed1993

[Motor neuropathy with conduction blocks].

A series of 4 patients with pure, chronic and progressive motor neuropathy whose main clinical characteristics were asymmetric and distal weakness of the upper limbs, myokymia and fasciculations is presented. There were no sensory impairment and amyotrophy was observed in only one case. This picture suggested the diagnosis of motor neuron disease (MND). However, neurophysiologic examination demonstrated the presence of multifocal conduction blocks (CB) of the motor axons which were preferentially located in the proximal nerve segments and always at points atypical to nerve compression. The peripheral sensitive conductions and the somatosensory evoked potentials were normal, even through the nerve segments where the CB were located. Since this is a treatable potentially reversible syndrome, this motor neuropathy with CB should be included in the differential diagnosis of MND.

Adult↗
PubMed1993

Liver damage and plasma concentrations of paracetamol and its metabolites after paracetamol overdosage in mice.

The effects of single oral and intraperitoneal (i.p.) overdoses of paracetamol (500 mg/kg) were studied in mice. The correlation between hepatocellular damage and plasma levels of paracetamol metabolites derived from the oxidative pathway were also investigated. Animals were killed at different intervals (1, 2.5 and 6 h) after drug administration. Plasma concentrations of paracetamol and its sulphate, glucuronide, cysteine and mercapturate conjugates were determined by HPLC. Paracetamol plasma levels were significantly higher at 1 and 2.5 h after i.p. administration as compared to oral administration (p = 0.01 and p = 0.02, respectively). Plasma levels of mercapturic acid conjugate were significantly higher at 6 h after i.p. administration (p = 0.04). After 6 h, animals given oral paracetamol showed significantly less necrosis than animals given i.p. paracetamol (p = 0.03). Plasma levels of mercapturate conjugate at 6 h showed a significant correlation with the severity of liver necrosis (r = 0.64; p = 0.02). The results suggest that i.p. paracetamol seems to be more adequate for hepatotoxicity studies in mice.

Acetaminophen↗
PubMed1992

Determination of paracetamol and its four major metabolites in mouse plasma by reversed-phase ion-pair high-performance liquid chromatography.

A reversed-phase ion-pair high-performance liquid chromatographic method has been used for the separation of paracetamol and its four major metabolites (glucuronide, sulphate, cysteine and mercapturate conjugates) in mouse plasma samples. An ODS column was used and the mobile phase consisted of an aqueous solution of 0.01 M tetrabutylammonium chloride and 0.01 M Tris buffered to pH 5.0 with phosphoric acid, with methanol as the organic solvent. The gradient elution started with 30% methanol. After a delay of 0.5 min the methanol concentration was increased linearly to 75% over 7.5 min. The column was returned to the initial conditions after a delay of 1 min. A methanol solution of theophylline was added to the mouse plasma sample, centrifuged and immediately injected into the chromatographic system. The advantages of this method include good and rapid separation (last metabolite detected at 6.86 min), well resolved peaks, only a small amount of sample required for assay, adequate precision (no coefficient of variation was greater than 10% for paracetamol metabolites) and a high sensitivity (particularly for unchanged paracetamol and the cysteine conjugate).

Acetaminophen↗
PubMed1991

[Antibodies against Helicobacter pylori in gastroenterology personnel, patients and the healthy population].

We have studied the prevalence of IgG antibodies to H. pylori in gastroenterology personnel, patients and healthy blood donors to determinate if there is a presumable high risk of infection among the first group, frequently at risk of exposure to gastrointestinal secretions. The positive percentage of sera in the gastroenterology personnel was 30.4% and in the healthy control group (mean age 35.8 years) was 38.5% (p = 0.620). In the patient group, the rate of positive results was 90% and in their control group (mean age 58 years) was 78.1% (p = 0.269). However, the differences were statistically significant when groups of different ages were compared (p less than 0.001). The results obtained suggest that the variations in the antibodies levels are age related and do not confirm the presumably increased risk among the gastroenterology personnel.

Adult↗
PubMed1991

[Pneumococcal meningitis. 6-year review].

We have reviewed 29 episodes of pneumococcal meningitis seen in a 6-year period (1983-1988) in 11 pediatric patients and 16 adults. An underlying disease or condition was present in 81.5% of cases, in 55.5% there was an anatomical defect, either congenital, acquired or traumatic in origin. Gram stain of CSF was positive in 86% of cases, and latex test was positive in the 22 CSF samples analyzed with this technique. MIC for penicillin ranges from 1 to 2 mcg/ml in 51.7% of cases. These isolates were also resistant to tetracycline (100%), trimethoprim-sulfamethoxazole (100%) and chloramphenicol (87%). All strains isolated were sensitive to vancomycin, rifampin and cefotaxime. Of all 14 episodes due to penicillin-sensitive strains, 10 cases were treated with this drug and in 4 cases, third generation cephalosporins were prescribed. All cases showed good clinical response. Of all 15 episodes due to penicillin-resistant strains, vancomycin was used first in 10 cases, cefotaxime in three, moxalactam in one and ampicillin plus chloramphenicol in another. Treatment failures (one in cefotaxime and one in moxalactam group) were solved with vancomycin. Of all 12 patients treated with vancomycin, clinical and microbiological cure was achieved in 10 cases. Two additional patients died, one with sterile CSF after 45 days of admission and one few hours after admission. Our data give support to vancomycin as a useful therapeutic option in the treatment of pneumococcal meningitis due to penicillin-resistant strains.

Adolescent↗