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Biomedical subjects

F Vidal

Publications and source records attributed to F Vidal.

At least 127 records · Page 7Linked to original sources
PubMed1997

Immunological and virological activity of zalcitabine and zidovudine in combination in HIV-positive people with CD4 cell counts of between 200-500 cells/mm3.

We evaluated the effect of combination therapy with zidovudine (AZT) plus zalcitabine (ddC) in human immunodeficiency virus type 1 (HIV-1)-infected patients who had not previously received antiretroviral treatment ('naive' patients). The immunological and virological parameters evaluated were CD4 cell count, syncytium-inducing (SI) viral phenotype and plasma HIV-1 RNA copies/ml (HIV viral load). A total of 75 patients entered the study, with CD4 cell counts between 200 and 500 cells/mm3. All received zidovudine (200 mg) plus zalcitabine (0.75 mg) three times daily for 24 weeks. Treatment was well tolerated. However, four patients presented with anaemia (haemoglobin < 10.0 g/dl) and one patient had both anaemia and neutropenia (0.8 x 10(9) neutrophils/l). Combination therapy with zidovudine plus zalcitabine resulted in a pronounced improvement of virological and immunological markers. Approximately 25% of patients achieved undetectable plasma HIV RNA levels (< 200 copies/ml) at week 24. At the end of the study (24 weeks) a significant reduction (> 0.5 log) of plasma HIV RNA was observed in approximately 70% of patients and in 50% an even greater decrease (> 1 log) was achieved. The most significant decrease in mean plasma HIV RNA levels was observed at week 4, whereas the highest increase in CD4 cell count was found at week 24. Approximately 80% of patients who showed baseline plasma HIV RNA levels below 20000 copies/ml had less than 5000 copies/ml at week 24. The plasma HIV RNA reduction observed at week 4 was significantly maintained at week 24. Therefore, we can rapidly select those who will not respond to therapy and adjust the treatment after a short interval. Our study supports the idea of early therapy because all patients who reached undetectable levels of plasma HIV RNA at week 24 had at baseline a median plasma HIV RNA load of 2560 copies/ml. In conclusion, zidovudine in combination with zalcitabine was well tolerated in the majority of patients and led to a significant reduction in plasma HIV RNA copies in most of the patients with initial viraemia lower than 20000 copies/ml.

Anti-HIV Agents↗
PubMed1997

[Subconjunctival anesthesia: an alternative for vitrectomy in mitochondrial myopathy].

The case of a 63-year-old woman with mitochondrial myopathy with palpebral ptosis and nighttime nasal home oxygen therapy is reported. The patient successfully underwent outpatient vitrectomy with subconjunctival anesthesia, receiving no premedication or sedation during the operation. Subconjunctival analgesia was provided, with prior instillation of an anesthetic collyrium followed by subconjunctival injection of 1 ml of 0.4% bupivacaine and 2% lidocaine. Analgesia during surgery was satisfactory. We review the possibilities of using this technique in patients at high risk of presenting postoperative complications after general anesthesia, and discuss the possible side effects on musculature when peribulbar or retrobulbar anesthesia is provided.

Anesthesia, Local↗
PubMed1996

Epidemiology and outcome of Pseudomonas aeruginosa bacteremia, with special emphasis on the influence of antibiotic treatment. Analysis of 189 episodes.

OBJECTIVE: To evaluate the trend in incidence of Pseudomonas aeruginosa bacteremia, underlying conditions of patients, mortality rate, and factors associated with poor outcome. PATIENTS AND METHODS: Medical charts of 189 consecutive episodes of P aeruginosa bacteremia, detected between January 1, 1991, and December 31, 1994, were prospectively evaluated. Associated risk factors, treatment, and outcome were recorded. RESULTS: Pseudomonas aeruginosa bacteremia represented 5.7% of the total number of bacteremias, 6.9% of nosocomial bacteremias, and 23.6% of nosocomial gram-negative bacteremias. There were 1.5 episodes per 1000 discharges. These numbers were slightly lower than those recorded at our hospital 10 years earlier. Human immunodeficiency virus infection was the most frequent underlying disease (28/189 [15%]). Overall mortality was 18% (34/189). The presence of fatal underlying disease (P < .001), surgery (P = .001), pneumonia (P = .02), and severe sepsis (P < .001) were associated with poor prognosis, the mortality of the patients with these variables being 28%, 28%, 47%, and 62%, respectively. The presence of inappropriate definitive antimicrobial treatment became an independent factor predictive of death (P = .04) only when the subset of patients with intravenous catheter-associated bacteremia was excluded from the analysis. The survival rate was no greater in patients who received 2 or more antibiotics active in vitro against P aeruginosa than in those who received only 1. Neutropenia was not associated with increased mortality. The use of colony-stimulating factors did not affect the outcome of the neutropenic patients. CONCLUSIONS: The rate of P aeruginosa bacteremia is falling slightly at our hospital. The emergence of the human immunodeficiency virus epidemic has had a considerable impact on both epidemiology and mortality. The presence of severe underlying disease, surgery, pneumonia, and, especially, severe sepsis are associated with a poor outcome. With the exclusion of patients with intravenous catheter-associated P aeruginosa bacteremia, the administration of an appropriate antimicrobial therapy is essential to a good outcome. Treatment with 1 active antibiotic seems to be sufficient.

Aged↗
PubMed1996

Brain activation induced by estimation of duration: a PET study.

Duration information about a visual stimulus requires processing as do other visual features such as size or intensity. Using positron emission tomography, iterative H215O infusions, and statistical parametric mapping, we investigated the neural correlates of time processing. Nine normal subjects underwent six serial rCBF. Three tasks were studied: (a) A temporal generalization task (D task) in which the subjects had to judge (by pressing one of two keys) whether the duration of the illumination of a green LED was equal to or different from that of a previously presented standard; (b) An intensity generalization task (I task) in which the judgment concerned the intensity of the LED; and (c) A control task (C task) in which the subjects had to press one of the two keys at random in response to LED illumination. A significant increase in rCBF during the D task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, anterior cingulate cortex, vermis, and a region corresponding to the left fusiform gyrus. A significant increase in rCBF during the I task, compared to that during the C task, was observed in right prefontal cortex, right inferior parietal lobule, right extrastriate cortex, anterior cingulate cortex, left inferior parietal lobule, vermis, and two symmetrical regions corresponding to the fusiform gyri. No significant activation was observed in the D task when compared to that in the I task. We propose that these cortical maps are best explained by the recruitment of visual attention and memory structures, which play a major role in prospective time judgements as indicated by behavioral studies. The data also suggest that the temporal dimension of a visual stimulus is processed in the same areas as other visual attributes.

Adult↗
PubMed1996

[Pleural effusion as initial presentation of rheumatoid arthritis. Cytological diagnosis].

A 24-year-old woman with an unremarkable history presented with a large right-sided pleural effusion. Analysis of the pleural fluid showed a sterile exudate with a low sugar level. Complementary analyses were unable to pinpoint the etiology. The effusion was drained and the patient was released with no specific diagnosis. Nine months later the effusion recurred and the initial laboratory analyses were the same. Pleural fluid cytology revealed the presence of an amorphous necrotic background and non-small cells with multiple nuclei, two signs that constitute part of the pathognomonic triad of rheumatoid pleural effusions, the third characteristic benign fusiform histocytes. The biochemical characteristics of the pleural fluid thus suggested rheumatoid pleural effusion, and cytology confirmed the diagnosis. Corticoid therapy effected spectacular recovery, but when the dose was reduced, rheumatoid symptoms presented in the joints. Rheumatoid arthritis should be considered as a possible explanation for unexplained pleural effusion. Cytology must be used for diagnosis.

Adult↗
PubMed1996

Nimodipine fails to enhance the analgesic effect of slow release morphine in the early phases of cancer pain treatment.

We assessed nimodipine's ability to increase the analgesic effect of morphine in 32 patients suffering from cancer pain in a double-blind, placebo controlled cross-over study. Morphine administration began a few days before the start of the study. The analgesic effects of two combinations were compared: morphine (M) plus placebo (P) and morphine plus 90 mg/24 h of nimodipine (N). The study lasted 8 days, including the wash-out period, and the following sequence of treatments was applied: M + P or M + N on days 1, 2 and 3; only M on days 4 and 5; and M + N or M + P on days 6, 7 and 8. Morphine dose was individualised according to the intensity of the patient's pain and the same dose was maintained throughout the study period. Analgesic response was evaluated using four 10 cm visual analogue scales of quantitative variables for pain intensity, pain relief, sleep quality and mood. A verbal rating of qualitative variables was also scored following validated descriptors of pain in the Spanish language. No significant statistical differences were found in analgesic effect between combined treatment with nimodipine or placebo, as measured on any of the scales. In order to take into account both the short duration of treatment (8 days), and nimodipine's pharmacokinetic characteristics (half-life of 6 h and steady state of 36 h), we compared treatment with nimodipine or placebo on the third day of use, at which time, likewise, there were no statistically significant differences on any of the scales. However, when the same statistical tests were used for comparison of results with pre-treatment baseline values, highly significant differences between mean scores on the scales for pain relief and pain intensity were found. Based on these negative results we conclude that nimodipine given orally at a dose of 30 mg every 8 h does not enhance analgesia when associated with morphine in the early phases of treatment for cancer pain. Our study also gives clear evidence of a placebo effect.

Administration, Oral↗
PubMed1996

The "short-long" reaction time effect in duration programming.

The programming processes concerned with response duration were studied in a precueing and in a priming reaction time (RT) paradigm. Participants had to produce a motor response of a specified duration as soon as possible after a response signal (RS) preceded by a warning signal (WS), which could deliver information on 2 response parameters (duration and effector). In Experiment I (precueing; N = 12), 3 effectors (the right hand, the left hand, or the knees) and 3 durations (.7, 2.5, or 5.5 s) were contrasted. Two responses differing in their biomechanical features were required in 2 blocks of trials: Subjects had to accurately time the duration of either a sustained button press or an interval between 2 brief presses. The RT patterns revealed a short-long effect: Shorter RTs were produced before the short duration than before the longer, provided that the duration was not precued. This short-long effect occurred whatever type of response and effector were involved. Two conclusions were reached. First, response duration was included in the motor program elaborated before execution, whatever the biomechanical features of the response; and, second, the program for the short duration was activated on all trials and was used as a basis for programming longer durations when needed. These conclusions were tested in Experiment 2 (priming; N = 12), in which a small proportion of invalid trials concerning duration was provided. Thus, the duration required by the RS differed from that primed by the WS. Two durations (.7 or 2.5 s) and 2 effectors (the index or the middle finger) were involved. In the invalid trials, the responses of short and long durations did not yield any RT differences, thus confirming the particular status of the short duration. This suggests that deprogramming operations (which lengthen the RT) are needed after a RS to produce short response durations but not after a RS to produce long response durations in the invalid trials.

Journal Article↗
PubMed1996

Absence of an early pre-emptive effect after thoracic extradural bupivacaine in thoracic surgery.

We have determined if thoracic extradural block before surgical incision for thoracotomy produces pre-emptive analgesia. Using a double-blind, placebo-controlled, crossover design, 45 patients (ASA II-III) undergoing posterolateral thoracotomy for lung resection were randomized to one of three groups: group 1 received 0.5% bupivacaine and adrenaline 1/200,000 (B+E) 8 ml through a thoracic extradural catheter (tip T3-T5) 30 min before skin incision and saline 8 ml 15 min after skin incision; group 2 received saline 8 ml extradurally before incision and B+E 8 ml after incision; group 3 received saline 8 ml extradurally before and after incision. General anaesthesia was induced and maintained with propofol, alfentanil and atracurium. The alfentanil infusion was stopped before chest closure and fentanyl 50 micrograms in saline 10 ml was given extradurally. Patient-controlled extradural analgesia (PCEA) was commenced with 0.125% bupivacaine, adrenaline 1/400,000 and fentanyl 6 micrograms ml-1 (continuous rate of 2 ml h-1 and supplementary doses of 0.5 ml per 6 min). Visual analogue scale (VAS) scores (recorded at rest, on mobilization and after cough), verbal rating scale (VRS) (recorded at rest), number of successful PCEA demands and complications were measured during the first 48 h after operation. There was no significant difference between groups, either in PCEA requirements (P > 0.21) or in VAS scores (either at rest, during mobilization of the ipsilateral arm of surgery or after cough). No significant differences between groups were found in the VRS. Thoracic extradural block with bupivacaine did not produce an early preemptive effect after thoracotomy.

Adult↗
PubMed1996

Incidence of chromosome 21 disomy in human spermatozoa as determined by fluorescent in-situ hybridization.

We have evaluated the incidence of chromosome 21 disomy in decondensed sperm heads from nine normal men using a locus-specific DNA probe for chromosome 21, and a centromeric probe for chromosome 6 as a control. The results show that the incidence of chromosome 21 disomy (0.38%) is significantly higher than disomy for chromosome 6(0.14%). No differences were found among the individuals analysed.

Adult↗
PubMed1996

Thoracic epidural anesthesia via the lumbar approach in infants and children.

BACKGROUND: In upper abdominal or chest surgery, the segmental approach to thoracic epidural space has the advantage of reducing the total dose of local anesthetic needed. This approach, however, is associated with greater risk of neurologic damage or dural puncture. The aim of this study was to assess the success and the degree of difficulty in advancing a 19-G catheter from the lumbar epidural space to the thoracic level in patients aged 0-96 months. METHODS: In 39 patients undergoing abdominal surgery, the cutaneous distance between the L4-L5 and T10-T11 interspaces was measured, and an appropriate length of 19-G catheter was inserted into the epidural space through an 18-G Tuohy needle with bevel directed cephalad. The intent was to advance the full length of catheter measured to reach the objective. The tips were observed radiologically, and all those positioned cephalad to the T12 level were considered well placed. The degree of difficulty in advancing the catheter was classified as easy, difficult, or impossible. Complications reported were vascular and/or spinal puncture and difficulty removing the catheter. RESULTS: The catheter tip reached T10-T12 in 7 patients, L2 in 1, L3 in 8, and L4-L5 in 23. Forty-eight percent of the catheters described as easily advanced remained at the L4-L5 level, and only 22% reached the desired level. Difficult insertions occurred in eight patients, in whom the objective was never reached. One case of intravascular insertion was reported. All catheters were removed without difficulty. CONCLUSIONS: The 19-G catheter is inappropriate for use in reaching the thoracic epidural space by the lumbar approach. Easy entrance of a catheter is not a reliable sign of having reached the desired level.

Anesthesia, Epidural↗