PubMed Health⌕ Search

Biomedical subjects

M Rodríguez

Publications and source records attributed to M Rodríguez.

At least 217 records · Page 12Linked to original sources
PubMed1997

[Prevalence of neurocysticercosis in individuals affected by epilepsy].

INTRODUCTION: In this investigations, was carried out a neurocysticercosis (NC) prevalence study during seven months in the Instituto Neurológico de Antioquia with the purpose of known neurocysticercosis frequency as cause of epilepsy in patients older than ten years that we attended in our institute. MATERIAL AND METHODS: Computerized tomographies (CT) were made to 503 patients, with epilepsy, 24.7% of them were CT positive for NC. Cysticercosis enzyme linked immunoelectrotransfer blot (EITB) and enzyme linked immunoabsorbent assay (ELISA) test were made to 178 patients, 19.6% were EITB positive for NC and 5% ELISA positive for NC. Results. From this result it is possible to infer that about 8% of the 503 patients with epilepsy had cysticercosis, according to EITB that is the golden assay for NC. The CT and ELISA test had 94.3% and 27.7% sensitivity, respectively, according to EITB. The specificity of the CT for NC was 49.2% and specificity for ELISA test was 100% as compared to EITB. The multivariate analysis with logistic regression allowed to establish association of positive EITB with factors such as male sex, eating pork, headaches and multiple lesions in CT. CONCLUSIONS: Prevention and education actions are necessary for the interruption of the neurocysticercosis transmission chain in order to diminish the high prevalence of epilepsy in the country and its complication and consequences.

Adult↗
PubMed1997

[Classic strategies for diagnosis of cryptosporidiosis in patients with AIDS and chronic diarrhea].

Cryptosporidium sp., a protozoa organism, has been increasingly recognized in association with severe enteritis in patients with the Acquired Immunodeficiency Syndrome. The studied subjects included 84 adult patients with AIDS and chronic diarrhea. We describe 14 patients with intestinal infection caused by Cryptosporidium sp. The mean CD4 count in these patients was < or = 300 cells/mm3 (7 out of 14). Examination of duodenal aspirates and feces included dimethylsulfoxide, auramine and acid-fast preparation of concentrated samples. We carried out videoesophagogastroduodenoscopy (VEDA) to visually inspect the mucosa and obtain biopsy specimens. VEDA revealed granular duodenum in ten patients and jasper duodenum in one of them. Duodenal biopsy specimens were stained with hematoxylin-eosin, Giemsa and Azure II. Histologic changes included atrophy (3/14), duodenitis (2/14) or both (3/14). Transmission electron microscopy was used for the identification of developmental stages of Cryptosporidium sp.

AIDS-Related Opportunistic Infections↗
PubMed1997

[Acute hepatitis associated with terbinafine].

Oral terbinafine is a recently introduced antifungal drug with slight side effects that rarely includes liver involvement. A case of toxic hepatitis secondary to terbinafine administration in a patient with no previous history of liver disease and in whom other possible causes of liver damage and histologic study were performed is reported. A mixed lesion was presented with predominance of cholestasis. The initial worsening following discontinuation of the drug is of note as are the prolonged course of the enzymatic alterations which normalized at one year. The precise mechanism by which terbinafine produced liver damage is unknown and is probably due to an idiosyncratic type reaction.

Acute Disease↗
PubMed1997

[Morphological study of Enterocytozoon bineousi in patients with AIDS and chronic diarrhea].

Microsporidia are protozoan parasites responsible for significant gastrointestinal disease in patients infected with the human immunodeficiency virus. We report the clinical features of three patients with chronic diarrhea and intestinal microsporidiosis caused by Enterocytozoon bieneusi. The average value for CD4 in these patients was < or = 50 cells/mm3. The spores were detected in smears from stool samples and duodenal aspirates stained with trichrome blue in all patients. Light microscopy of semi-thin plastic sections revealed parasites and spores in the enterocytes and were associated with villous atrophy (2 out of 3). Thin section-electron microscopy showed a variety of developmental stages of the microsporidio. Patients treated with Albendazole had an unsatisfactory clinical response to therapy. Enterocytozoon bieneusi infection may be an important cause of diarrhea in patients with AIDS in our country.

AIDS-Related Opportunistic Infections↗
PubMed1996

Effects of aging on N-methyl-D-aspartate (NMDA)-induced GnRH and LH release in female rats.

In order to evaluate if the changes of the hypothalamic-pituitary-ovary axis that induce a decrease in fertility and modifications in the sexual cycles during senescence involve modifications in the regulatory action of excitatory amino acid neurotransmission on GnRH neurons, we measured the in vitro effects of NMDA on GnRH release by the anterior preoptic and medial basal hypothalamic areas (APOA-MBH) of castrated aging (18 months old) and young (90 days of age) rats. In a second series of experiments the in vivo LH release response to intrahypothalamic (push-pull) administration of NMDA to aged and young castrated female rats was also determined. A similar rate of basal GnRH release was observed in old and young rats during the incubation time. The addition of NMDA to the medium significantly increased GnRH release in both groups; nevertheless, the GnRH release response to NMDA was significantly lower in old (P < 0.01) than in young rats (Young: Basal: 50 +/- 10; NMDA 15': 410 +/- 63, 22,5': 1,469 +/- 300; Old: Basal: 47 +/- 10; NMDA 15': 210 +/- 30; 22,5': 350 +/- 65 ng/GnRH/mg.protein). The LH levels measured throughout the in vivo experiments indicated that basal LH concentrations were significantly lower in the aged group. The mean LH concentrations (fractions 1 to 6) was significantly lower in the aged group (Young: 3.9 +/- 0.07, Old: 2.4 +/- 0.03 ng/ml, P < 0.01). The LH release response to NMDA measured 10 min after the intrahypothalamic administration of the glutamate agonist was significantly lower in aged rats (4.2 +/- 1.6 ng/ml) as compared to young animals (18.0 +/- 6.1 ng/ml; P < 0.05). LH levels in young rats increased to 580% vs., and only 47% in aged rats as compared to previous basal values. In conclusion, present results demonstrate that the GnRH responses to NMDA neurotransmission, which has a predominantly excitatory effects on GnRH neurons, is significantly decreased in old rats, these data give further support to the hypothesis that a decrease in the excitatory inputs to GnRH neurons could be directly involved in the reduction of the hypothalamic-pituitary-ovary axis activity observed during aging.

Aging↗
PubMed1996

Hysteresis of the PTH-calcium curve during hypocalcemia in the dog: effect of the rate and linearity of calcium decrease and sequential episodes of hypocalcemia.

Several studies have shown the presence of hysteresis of the parathyroid hormone (PTH)-calcium relationship in both normal humans and hemodialysis patients; for hypocalcemia, hysteresis is defined as a lower PTH level for the same serum calcium during the recovery from than the induction of hypocalcemia. However, some have questioned whether hysteresis is only a function of the rate and/or direction of change in calcium, and others have proposed that hysteresis is due to depletion of PTH stores. To address these issues, two groups of dogs were studied. To induce hypocalcemia, sodium EDTA (50 mg/kg) was infused either over 60 (termed slow) or 30 (termed fast) minutes; immediately after the cessation of the ethylenediamine tetracetate (EDTA) infusion, calcium chloride (0.75 mEq/kg) was infused over 60 or 30 minutes, respectively, to correct the hypocalcemia. The EDTA infusion produced a linear decrease in serum calcium by progressively increasing the infusion rate at regular intervals. A second cycle of hypocalcemia and recovery using the same protocol was started immediately after the completion of the first cycle. To determine whether a nonlinear decrease in the serum calcium affected the PTH response to hypocalcemia, a third group of dogs, termed superfast, was studied; in this group, EDTA was infused for 30 minutes at a constant rate of 50 mg/kg. The hysteretic loops of PTH produced by the two sequential slow and fast cycles and the superfast cycle during the induction of and recovery from hypocalcemia were similar. Moreover, the maximal PTH level for the two sequential slow and fast cycles and the superfast cycle was not different even though the rates of calcium decrease varied and the calcium decrease was nonlinear in the superfast cycle. In conclusion, (1) since hysteresis was reproducible and the maximal PTH was not different during two sequential cycles of hypocalcemia, hysteresis is not due to PTH depletion; (2) the PTH-calcium curve is not affected by the rate at which hypocalcemia is induced; and (3) the maximal PTH level is not influenced by either the rate or linearity of the reduction in serum calcium.

Analysis of Variance↗
PubMed1996

1 alpha, 25-dihydroxyvitamin D3 (calcitriol) induces apoptosis in stimulated T cells through an IL-2 dependent mechanism.

The steroid hormone 1 alpha,25-dihydroxyvitamin D3 (calcitriol) has been shown to inhibit PHA-induced T-cell proliferation. In the present work we show that calcitriol caused a concentration-dependent decrease in the viability of PHA stimulated but not unstimulated T lymphocytes. Under microscopy, nonviable cells exhibit classic features of programmed cell death or apoptosis. In addition, the same concentration of calcitriol induces a blockage in the G1 phase of T cell cycle and decreased secretion of IL-2, which was correlated with the extent of apoptosis. Thus, addition of exogenous IL-2 reverted both the cell cycle block and the apoptotic cell death induced by calcitriol. This data indicates that calcitriol induced apoptosis in PHA-stimulated T cell, and suggests that this action is mediated through suppression of IL-2 secretion.

Animals↗
PubMed1996

Time and frequency domain analysis for the assessment of heart autonomic control in Parkinson's disease.

In order to evaluate autonomic regulation in Parkinson's disease, the heart-rate responses to passive head-up tilt and the spectral analysis of spontaneous heart rate variability in supine position were studied in 18 young (30.8 +/- 1.38 years old) and 13 aged (61.9 +/- 1.61 years) healthy controls and 13 patients with Parkinson's disease (62.9 +/- 1.55 years). Patients were evaluated in the University Hospital of the Canary Islands by a neurologist and a specialist in rehabilitation. Finally, a computerized procedure developed in the Dept. of Physiology of La Laguna University was used to quantify the autonomic regulation of heart-rate (HR) variability. In relation to the younger group, elderly controls showed a reduction in the amplitude and no differences in the latency of the three successive peaks of HR response to tilt. In relation to the elderly matched controls, the Parkinson group showed a slight decrease for the second response amplitude and no differences for both the first or third response amplitude and the latency of the three responses. In the frequency domain analysis of the spontaneous HR oscillation in supine position recording, the elderly and Parkinson groups showed a decrease in the power spectrum for low frequency (<0.04Hz; thermoregulation related band), mid frequency (0.04-0.15Hz; related to sympathetic activity in response to baroreceptors stimulation) and high frequency (0.15-0.4Hz; related to sympathovagal tonus activated by respiratory movements). In relation to elderly controls, the Parkinson group showed lower power in the three spectral bands studied. Present data support the hypothesis that both sympathetic and parasympathetic control of heart activity are impaired in Parkinson's disease and that this dysfunction can be assessed by combining time-domain and frequency-domain analysis of HR changes.

Adult↗
PubMed1996

Selectivity of methyl-fructoside synthesis with beta-fructofuranosidase.

Enzyme synthesis of methyl fructoside was studied using beta-fructofuranosidase from Sacharomyces cerevisiae and sucrose and methanol as substrates. Taking into account the inhibition and deactivation effects of methanol on the enzyme, a system with 4.9M (20%, v/v) methanol was selected. At this alcohol level, 35% of sucrose is converted to fructoside at low or high substrate concentrations. The effect of enzyme concentration, pH, and temperature on both the synthesis and the hydrolysis of the fructoside was investigated. It was found that if the reaction proceeds at pH 6.0, 4 degree C and/or 0.014 mg/mL (3 U/mL) of beta-fructofuranosidase at varying sucrose concentrations, methyl fructoside may be obtained with a minimum loss of the fructoside at the end of the reaction.

Biotransformation↗
PubMed1996

Obstructive and restrictive pulmonary dysfunctions in Parkinson's disease.

Pulmonary dysfunction was investigated in fifty-eight Parkinson's patients. Clinical disability was assessed by the Unified Parkinson's Disease Rating Scale. Pulmonary dysfunction was studied by spirometry with flow-volume loops, body plethysmography with lung volumes computation and maximal inspiratory and expiratory static mouth pressures. Forced vital capacity (FVC), forced expiratory volume in 1 min (FEV1), FEV1/FVC% and arterial PO2 and PCO2 were significantly below normal values. Residual volume (RV) and total rows were above normal values. Thirty-six had upper airway obstruction as judged by inspiratory flow peaks (PIF) < 3 l/s and FEV1/PEF (expiratory flow peak) > 8.5 l/min and MEF50/MIF50 > 1. Eighteen patients had a central (FEV1 < 80% and FEV1/FVC% < 80% of normal values) or peripheral (maximal expiratory flow between 75% and 25% of FVC and maximal expiratory flow after expiration of 50% below 70% of normal values) obstructive pattern. Sixteen patients had a restrictive dysfunction as judged by a total lung capacity < 85% or FVC < 80% with FEV1/FVC% > 80%. Sixteen patients had air trapping (RV > 120% and RV/TLC > 40%) and seven patients had lung insufflation (TLC > 120%). Rigidity, Rx signs of cervical arthrosis and limitations for passive movement of neck were higher in patients with central or peripheral airway obstruction. Bradykinesia and Rx signs of dorsal arthrosis was higher in patients with upper airway obstruction. Restrictive dysfunction was not related to tremor, rigidity or bradykinesia. The present data support the hypothesis that Parkinson patients present a high risk for pneumologic disturbances. These pulmonary dysfunctions are induced by the simultaneous action of a group of factors including the degree of bradykinesia or rigidity and the musculoskeletal limitations of vertebral column probably induced by chronic anomalous posture.

Humans↗
PubMed1996

Simulation of control strategies for the cattle tick Boophilus microplus employing vaccination with a recombinant Bm86 antigen preparation.

Current strategies for the control of the cattle tick Boophilus microplus include the use of chemicals as the principal control method. These methods, however, have met with partially successful results. The recent development of immunological methods for the control of the cattle tick has opened new possibilities for the design of control strategies. Employing the results obtained by us in experiments testing the effect of vaccination with the recombinant vaccine, Gavac (Heber Biotec S.A.), on tick populations, we have developed a model to evaluate, through a computer program, the efficacy of the vaccine as a control method. The action of the vaccine on the control of tick populations was simulated and the specific serum antibody titers required to decrease the tick population in the field were calculated. The specific serum antibody titer required to decrease the tick population in the field after the first vaccination scheme was found to be > or = 57,200 and the antibody titer required to maintain this effect when the vaccine is already acting and after successive revaccinations was found to be > or = 27,500. Considerations about revaccination schemes and combination between vaccination and acaricide treatments as possible control strategies are discussed.

Animals↗
PubMed1996

Obstructive and restrictive pulmonary dysfunction increases disability in Parkinson disease.

OBJECTIVE: The purpose of this study was to determine in Parkinson disease the impact of pulmonary dysfunction on daily living activities (DLA). PATIENTS: Extrapyramidal motor impairment, pulmonary dysfunction, and DLA disabilities were studied in 58 Parkinson patients consecutively enrolled in a rehabilitation service at a university hospital. MAIN OUTCOME MEASURES: Extrapyramidal motor impairments were assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) and the DLA disabilities by the UPDRS, Hoehn-Yahr, and Schwab-England scales. The pulmonary dysfunctions were assessed by spirometry with flow-volume loops, body plethysmography with lung volumes computation, and maximal inspiratory and expiratory static mouth pressures. RESULTS: Parkinson patients showed important modifications of pulmonary function with a decrease in forced vital capacity, forced expiratory volume in the first minute, and arterial PO2, and an increase in residual volume and total airway resistance (RAW). In addition, they showed a high incidence of airway ventilatory obstructions and restrictive dysfunction. The impact of lung disease on daily living activities in Parkinson disease patients was higher in subjects with restrictive pulmonary dysfunctions (Schwab-England test and turning in bed and adjusting bedclothes, walking, falling, and freezing when walking items of UPDRS) and airway obstructions (handling utensils, dressing and hygiene items of UPDRS). CONCLUSIONS: Airway obstructions or restrictive pulmonary dysfunctions present a high prevalence in Parkinson disease, contributing as a main factor for DLA dysfunctions. The evaluation and rehabilitation of respiratory disturbances should be systematically included in the management of these patients.

Activities of Daily Living↗
PubMed1996

Immunocytochemical detection of growth factors (PDGF and TGF beta) in equine chronic pneumonia.

The roles played by platelet-derived growth factor (PDGF) and transforming growth factor beta (TGF beta) in the development of pulmonary fibrosis in equine chronic pneumonia varied greatly. Macrophages, epithelial cells and fibroblasts were identified as a source of PDGF, the principal role of which was related to its mitotic effect on epithelial cells, and particularly on fibroblasts in the final phase of the disease. TGF beta was detected in epithelial cells in all three phases of the disease and in fibroblasts in the last phase. However, the role of TGF beta in this pulmonary disease is not clear because its expression in the cytoplasm of fibroblasts in areas of strong collagenation during the last phase was weak. Nonetheless, it was responsible for the production and release of collagen during the stage of total fibrosis.

Animals↗
PubMed1996

EEG delta activity: an indicator of attention to internal processing during performance of mental tasks.

In previous papers we proposed that an increase in delta EEG activity during mental tasks might be related to an increase in subjects' attention to internal processing. In this paper we have made a narrow band analysis to detect those EEG frequencies that change selectively during the performance of a mental task that requires attention to internal processing. Two different experiments were performed: (1) a difficult mental calculation task and a control stimulus with the same physical characteristics as the arithmetical symbols were presented in random order; (2) the Sternberg paradigm for the analysis of short term memory using a memory set of 5 or 3 digits was also presented in random order. Referential recordings to linked ears were obtained in all leads of the 10/20 system. In the first experiment, the increase of power from 1.56 to 5.46 Hz was observed only during the performance of the task and not during the control condition. In the Sternberg paradigm, the increase of power from 1.56 to 3.90 Hz was greater during the difficult than during the easy condition. These results support our hypothesis that an increase in delta activity may be related to attention to internal processing during the performance of a mental task.

Adult↗
PubMed1996

High phosphorus diet increases preproPTH mRNA independent of calcium and calcitriol in normal rats.

Phosphorus retention favors secondary hyperparathyroidism by decreasing calcitriol synthesis and serum calcium levels. However, a direct effect of high extracellular phosphorus on parathyroid (PTH) function, gene expression, and cell proliferation is still controversial. Normal rats were fed standard (St; 0.6% calcium, 0.6% phosphorus) or high phosphate (HP) diet (0.6% calcium, 1.2% phosphorus) for 18 days. To rule out transient decreases in serum calcium or calcitriol levels, sets of animals were sacrificed at different time periods after the last feeding (2, 4, 8, 12 or 24 hr). The HP diet led to hyperphosphatemia and secondary hyperparathyroidism and maximum differences in PTH levels were observed eight hours after feeding (St 29.4 +/- 15 vs. HP 87.9 +/- 56 pg/ml, mean +/- SD; P = 0.01). High levels induced by the HP diet prevented both hypocalcemia and low calcitriol levels at each study point. The HP diet also promoted a significant increase of PTH mRNA levels that peaked about eight hours after feeding (100% increase). This was confirmed at the cellular level by in situ hybridization. Parathyroid glands from animals fed the HP diet showed a 25% increase in volume with respect to the St diet (P = 0.01), and a typical pattern of hyperplasia was found. Parathyroid vitamin D receptor (VDR) mRNA levels were not modified by the HP diet. In conclusion, parathyroid gene expression per cell and parathyroid cell hyperplasia are stimulated by high dietary phosphorus independently of calcium and calcitriol. This effect is not mediated by alterations in the gene expression of the parathyroid calcitriol receptor. Our findings emphasize the importance of the control of hyperphosphatemia in chronic renal failure patients.

Animals↗