Biomedical subjects

L Castillo

Publications and source records attributed to L Castillo.

136 records · Page 8Linked to original sources

PubMedDate not supplied

Influence of polymeric enteral nutrition supplemented with different doses of glutamine on gut permeability in critically ill patients.

OBJECTIVES: To evaluate the effect of glutamine-supplemented polymeric enteral formulas on the recovery of gut-permeability abnormalities in critically ill patients. METHODS: Twenty-three patients were randomized to receive a conventional casein-based enteral formula (ADN), ADN plus glutamine in a dose of 0.15 g x kg(-1) x d(-1) or ADN plus 0.30 g x kg(-1) x d(-1) of glutamine for 8 d. The lactulose mannitol permeability test (L/M) was performed at baseline and at the end of the study. Nineteen healthy volunteers served as controls for the L/M test. RESULTS: An increase in permeability compared with control subjects was observed in patients at baseline (mean +/- standard error of the mean; L/M ratio: 0.11 +/- 0.03 and 0.025 +/- 0.004, respectively; P < 0.02). The L/M ratio improved after the period of enteral nutrition as a whole (initial L/M: 0.11 +/- 0.03, final L/M: 0.061 +/- 0.01; P < 0.03), but no difference was found between groups. CONCLUSIONS: Even though polymeric enteral nutrition was associated with a significant improvement in the L/M ratio, glutamine supplementation did not show a specific influence in improving recovery of gut permeability in critically ill patients.

Adult↗

PubMedDate not supplied

Ultrastructural pathology of a Chilean case of tropical spastic paraparesis/human T-cell lymphotropic type I-associated myelopathy (TSP/HAM).

Human T-cell lymphotropic virus type I (HTLV-I), is the cause of endemic tropical spastic paraparesis (TSP) or HTLV-I-associated myelopathy (HAM). Because TSP/HAM is not a fatal disease, the neuropathology of this disease, albeit relatively well understood, is based on the examination of just a few incidental cases. Previously, we demonstrated peculiar lamellated structures, called "multilamellar bodies" (MLB). In this report, we present the ultrastructural neuropathology of a TSP/HAM case from Chile, with further detailed descriptions of MLB. It is tempting to suggest that MLB may represent specific ultrastructural markers of TSP/HAM. The pathology of the anterior and posterior horns was similar and was comprised of axonal degeneration, accompanied by extensive astrocytic gliosis. Lymphocytic infiltration, particularly observed as "cuffs" around blood vessels, was scattered among other cellular elements. Ultrastructurally, myelin sheaths were relatively well preserved, and some demyelinated but not remyelinated fibers were observed. Moreover, axons with abnormal accumulations of neurofilaments, suggestive of axonal degeneration, were detected. Several axons contained Hirano bodies. In many samples, glial processes replaced most of the remaining neuropil. In a few specimens of the anterior and posterior horns of the spinal cord, MLB were observed. These structures consisted of stacks of 30 to 40 electron-dense lamellae, which were interrupted by narrow electron-lucent spaces. All of the lamellae were immersed within an amorphous substance of intermediate density. Neurons of the dorsal root ganglia were basically normal except for increased lipofuscin accumulation. As in the spinal cord, myelinated axons were well preserved, but a few were demyelinated and surrounded by concentric arrays of Schwann cell membranes. Also, axons of the dorsal roots accumulated increased number of neurofilaments. Mast cells and Schwann cells were increased in number, the latter containing abundant pi granules and myelin fragments.

Astrocytes↗

PubMedDate not supplied

Epidemiology of epilepsy in Guaymi Indians from Bocas del Toro Province, Republic of Panama.

This cross-sectional study was conducted to describe the epidemiology of epilepsy in Guaymi Indians residing in Changuinola, a small town on Panama's Caribbean coast near Costa Rica. We randomly selected households and attempted to enroll all residents aged less than or equal to 1 year; 337 eligible subjects agreed to participate (93% response rate). We administered a standard neurologic disease screening examination to all subjects and, if any abnormality was found, we administered a standard neurologic evaluation. We detected 19 cases of active epilepsy; the mean age at onset was 12 years, and generalized tonic-clonic seizures were the most common diagnosis (10 of 19, 53%). The prevalence of active epilepsy among Caribbean coastal Guaymi (57/1000) is considerably greater than that in lower class Panama City populations (22/1000) or in other parts of the world. To identify risk factors for epilepsy, we collected epidemiologic data and serum (for Cysticercus antibody) from subjects with active epilepsy and from 44 age/sex-matched controls. Significantly more cases (47%) than controls (6%) had other family members with epilepsy (relative risk, RR = 14); 44% of cases and 13% of controls reported a history of febrile seizures during childhood (RR = 6).

Adolescent↗

PubMedDate not supplied

Septal fetal tissue transplants restore long-term potentiation in the dentate gyrus of fimbria-formix-lesioned rats.

Two groups of Sprague-Dawley male rats received bilateral aspirative lesions of the fimbria fornix under chloral hydrate anesthesia. One group (n = 9) received no further treatment (lesioned). In the second group (n = 8), a piece of septal fetal tissue, obtained at day E15-16, was implanted into each lesion cavity (transplanted). A third group consisted of shamlesioned rats (controls, n = 14). Two months after the operations, a recording electrode was implanted in the hilar region of the dentate gyrus of each animal, and a bipolar stimulating electrode was implanted in the perforant path. Long-term potentiation at 400 Hz was induced and followed for two hours. FF-lesioned rats showed an impaired potentiation of the field excitatory post-synaptic potential, which rapidly declined to basal levels within 15 minutes. The transplanted rats showed a normal potentiation of this parameter, similar to that seen in the control animals. A decrease in choline acetyltransferase activity in the hippocampi of the lesioned animals showed a tendency toward recovery after septal fetal tissue transplantation. In all the dorsal hippocampal areas of the lesioned animals, acetylcholinesterase histochemistry showed an almost complete loss of enzymatic activity, which was partially restored by the transplants. The improved synaptic plasticity in the transplanted animals might be related to septal transplant-induced recovery of mnemonic functions.

Acetylcholinesterase↗

PubMedDate not supplied

Hazardous pesticides in Central America.

Pesticides are an extensively documented occupational and environmental hazard in Central America. Yet, severe problems persist. Toxic pesticide use in the Region increased during 1985-1999. High exposure levels and ineffectiveness of personal protective equipment evidence the difficulties for risk reduction. Acute poisonings remain a severe problem. Delayed and/or long-lasting health effects include dermatoses, cancer, and genotoxic, neurotoxic, and respiratory effects. The use of hazardous pesticides persists through deficiencies in government-driven assessment and risk management; excessive focus on regional harmonization; short-term economic interests; strong links between industry and governments; aggressive marketing; weak trade unions; and failure of universities to reach decision makers. Regulation based on local data is lacking. An agreement of the Ministries of Health for restricting the most toxic pesticides in Central America has potential for progress. The most effective way to reduce risk is to greatly reduce pesticide use. Actions needed include development of multidisciplinary strategies for local studies on health and environmental impact of pesticides; development of sustainable nonchemical agricultural technologies; evaluation of interventions; extending and sharing of expertise within the Region; strengthening of unions and communities; and redefining the role of industry toward development of safer products, with responsible marketing and reliable information.

Academies and Institutes↗

PubMedDate not supplied

Experiences from long-term research cooperation between Costa Rican, Nicaraguan, and Swedish institutions.

This paper summarizes experiences from long-term ongoing cooperation between Swedish research institutions and institutions at the National Universities in Nicaragua and Costa Rica. 24 researchers and teachers from the Central American institutions and ten Swedish research students have been trained. In addition to three full doctoral and three licentiate (two-year PhD program) theses, the two programs have so far published 15 articles in English-language, international, refereed journals and about three times as many abstracts for conferences in more than ten countries. A "sandwich" model for training is recommended, where the southern researchers come to the wealthier partner for collaborative analyses and write-ups of the publications, while spending 50-75% of their time in their home countries for data collection. Such collaboration should be planned for a time span of at least eight years and include substantial numbers of researchers and students. Means to minimize the risk of brain drain are suggested. The collaboration has been important for the globalization of the research cultures at the participating institutions and has trained international experts.

Costa Rica↗

PubMedDate not supplied

Pulmonary function in survivors of Wilms' tumor.

The respiratory status of 47 patients surviving childhood Wilms' tumor was studied. The group that had received flank irradiation (which impinges on the lower lung) (n = 17) had a significantly lower mean percent predicted for forced expiratory volume in one second, residual volume, and total lung capacity when compared to those who had received no irradiation (n = 23). Those patients who had received whole-lung irradiation (n = 3) had significantly lower transfer factor for carbon monoxide and gas transfer per unit lung volume when compared to the nonirradiated group (n = 23). There was no significant difference in the prevalence of respiratory symptoms between the three groups. Patients receiving any form of radiotherapy for Wilms' tumor may have abnormalities of pulmonary function and should have pulmonary function tests performed as part of their long-term follow-up.

Adolescent↗

PubMedDate not supplied

[Simultaneous micro-transplantation of fetal mesencephalic cells to the striate and substantia nigra pars reticulata in hemi-parkinsonian rats. A study of behavior].

INTRODUCTION: Microtransplantation of fetal dopaminergic cells has been used over the past ten years with good results in models of Parkinson's disease. OBJECTIVE: To evaluate the effect of microtransplantation of fetal dopaminergic cells 'seeded' in the substantia nigra pars reticulata (SNpr) and striate (St) simultaneously. MATERIAL AND METHODS: The animals received a transplant or microtransplant of cells into the St and SNpr ipsilateral to the lesion in the substantia nigra pars compacta or to both regions. Depending on the site and technique used the following experimental groups were considered: I. Macrotransplantation to the St (n = 20); II. Microtransplant to the St (n = 20); III. Microtransplant to St + SNpr (n = 20); IV. Microtransplant to St + SNpr (n = 20); V. Macrotransplantation to SNpr (n = 20); VI. Microtransplantation to SNpr (n = 20); and VII. Control (lesion only) (n = 20). The rotations induced by D-amphetamine (5 mg/kg i.p.) and by apomorphine were studied 1, 2, 3 and 6 months and 3 and 6 months respectively after transplantation. Three months after transplantation we studied the motor asymmetry shown by the animals by means of the ladder test. RESULTS: The rotations were reduced in the groups with intrastriate transplantation. Comparison between the surgical techniques showed nonsignificant differences between them. The ladder test showed significant differences in use of the limbs in all experimental groups. Use of the left limb was significantly reduced in all groups. CONCLUSIONS: Modification of the rotations seems more sensitive to the site of transplant than to the technique used. It seems that the skills studied using the ladder test are not altered by the microtransplant technique.

Animals↗

PubMedDate not supplied

[Epidermal growth factor-responsive precursors with similar properties isolated from embryonic rat septum and striatum].

INTRODUCTION: The potential correspondence of precursor cells isolated from different brain regions is partially unknown. Since models and culture conditions used in several studies vary, comparison of precursor characteristics has been limited. OBJECTIVE: In this paper epidermal growth factor (EGF)-responsive precursors from the striatum and septum were isolated and their growth pattern in vitro were determined. We also evaluated the influence of fibroblast growth factor (FGF) and nerve growth factor (NGF) on the proliferation of these cells. MATERIAL AND METHODS: Dissociated cells from rat septum and striatum were cultivated in suspension with 20 ng/ml of EGF. Total cells quantification, immunocytochemical staining and neuron counts were used to evaluate cell proliferation and cellular phenotypes produced by EGF-generated cells. RESULTS: Considering both culture evolution and cellular growth we demonstrated a similar growth pattern of septal and striatal EGF-responsive precursors. Furthermore, the proliferation of both cells populations was supported by FGF. On the contrary, NGF neither had a proliferative effect nor affected cell survival. Upon differentiation, a small proportion of precursor cells differentiated into neuronal phenotype.

Animals↗

PubMedDate not supplied

[The Landry-Guillain-Barré-Strohl syndrome].

Landry-Guillain-Barré-Strohl syndrome or polyradiculoneuritis in children is becoming more common. The clinical picture is variable, it may be manifested by motor and sensory findings or by a combination of peripheral and cranial nerve signs and symptoms. This is a report of 60 patients observed at the DIF Children's Hospital between 1971 and 1977. The most significant early predictor of eventual incomplete recovery was the time required for improvement to begin after the maximum involvement was reached.

Child↗