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Biomedical subjects

J Lucena

Publications and source records attributed to J Lucena.

10 recordsLinked to original sources
PubMed2002

Ocular involvement in Takayasu's arteritis: response to cyclophosphamide therapy.

PURPOSE: To report a Takayasu's arteritis (TA) case with an intense ocular involvement and the response to monthly bolus of Cyclophosphamide. METHODS: Case report and literature review. RESULTS: Cyclophosphamide was useful to improve the TA symptoms without any additional treatment and any secondary effects. When this therapy was discontinued the ocular symptoms progressed. CONCLUSION: Although no definitive therapy has been established, Cyclophosphamide intravenous bolus may be useful to improve ocular symptoms of Takayasu's Arteritis, specially in early stages. There are not adequate descriptions in the literature concerning the effect of this treatment on the ocular manifestations of TA.

Adult↗
PubMed1999

Technical note: a device for obtaining time-integrated samples of ruminal fluid.

A device was adapted to allow for time-integrated sampling of fluid from the rumen via a cannula. The sampler consisted of a cup-shaped ceramic filter positioned in the ventral rumen of a cannulated cow and attached to a tube through which fluid entering the filter was removed continuously using a peristaltic pump. Rate of ruminal fluid removal using the device was monitored over two 36-h periods (at 6-h intervals) and was not affected (P > .05) by time, indicating that the system was not susceptible to clogging during this period. Two cows having ad libitum access to a totally mixed ration were used in a split-block design to evaluate the utility of the system for obtaining time-integrated samples of ruminal fluid. Ruminal fluid VFA concentration and pattern in samples collected in two replicated 8-h periods by the time-integrated sampler (at 1-h intervals) were compared with composite samples collected using a conventional suction-strainer device (at 30-min intervals). Each 8-h collection period started 2 h before or 6 h after feeding. Results indicated that total VFA concentration was not affected (P > .05) by the sampling method. Volatile fatty acid patterns were likewise unaffected (P > .05) except that acetate was 2.5% higher (P < .05) in samples collected 2 h before feeding and valerate was 5% higher (P < .05) in samples collected 6 h after feeding by the suction-strainer device. Although significant, these differences were not considered physiologically important. We concluded that use of the ceramic filter improved the sampling of ruminal fluid by simplifying the technique and allowing time-integrated samples to be obtained.

Animals↗
PubMed1997

Cerebellar cortex delayed maturation in sudden infant death syndrome.

The cerebellum shows afferent and efferent connections with intrinsic bulbar nuclei and plays an important role in respiration and cardiovascular control. Pathological and neurochemical abnormalities of bulbar nuclei including the arcuate nucleus have been postulated in sudden infant death syndrome (SIDS). Most of these abnormalities have been related to impairment in brain development. The cerebellar cortex has a well-documented evolution from fetal life until infancy; thus, it may be a very good model to assess brain maturation in SIDS. The present study was conducted to investigate changes in the cerebellar cortex in 19 SIDS cases compared with 12 age-related controls using morphological, quantitative, and statistical approaches. Five-microns paraffin sections from the midsagittal cerebellar vermis were stained with hematoxylin and eosin (H&E). Immunohistochemical staining was carried out using a polyclonal antiserum to glial fibrillary acidic protein (GFAP). Each case consisted of a 25-microns parallel paraffin section stained with H&E, where the cerebellar external granular layer (EGL) cell density was obtained in one field magnification (x1,000) using an optical dissector procedure on the basis of a stereological method. A statistically significant high EGL cell density, mostly related to the presence of immature bipolar, elongated neuronal cells of the premigratory zone with hyperchromatic, oval or poor differentiated nuclei, was observed in SIDS. In these cases, EGL expressed immunoreactivity for GFAP mainly in the subpial and the postmitotic zone. These findings demonstrate a delayed or slower decline in the number of EGL neurons in SIDS, suggesting either a prolongation of the growth phase related to postnatal cerebellar foliation or a delay in inward migration. These results suggest that in SIDS there is delayed maturation of the cerebellar cortex/EGL, which may support the hypothesized cardiopulmonary control dysfunction, leading to death in a vulnerable period of postnatal development.

Adult↗
PubMed1997

Dietary nucleotides might influence the humoral immune response against cow's milk proteins in preterm neonates.

The objective of this study was to evaluate the influence of dietary nucleotide supplementation in preterm infants during the first month of life on the intestinal permeability to lactulose, mannitol and to beta-lactoglobulin and on the development of circulating antibodies to beta-lactoglobulin and alpha-casein. Twenty-seven preterm infants were enrolled in the study; 11 of them were fed a standard low-birth weight milk formula and 16 infants were fed the same formula supplemented with nucleotides at similar levels to those found in human milk. Blood and urine samples were obtained at 1, 7 and 30 days of age. Serum beta-lactoglobulin, serum IgG antibody to alpha-casein and serum IgG antibody to beta-lactoglobulin were measured by ELISA. The lactulose/mannitol urinary excretion rate was measured by gas liquid chromatography. Neither the intestinal permeability to saccharides nor the intestinal absorption of beta-lactoglobulin were affected by the nucleotide supplementation. However, serum concentrations of IgG antibody to beta-lactoglobulin were higher in preterm neonates fed the supplemented formula than in those fed the standard formula. According to these results, dietary nucleotides might influence the maturation of the humoral immune response in preterm newborn infants.

Caseins↗
PubMed1996

Ependymal changes in sudden infant death syndrome.

The ependyma may befall a variety of pathogenic noxae during fetal life, resulting in histological changes which may persist after birth but are without clinical manifestations. Eight of a series of 19 children who died suddenly and unexpectedly, where no explanation as to the cause of death was found at autopsy, were shown to have diverse histological features involving the ependyma. Five micrometer paraffin-embedded brain tissue sections including frontal, temporal, occipital, and ventricular horns as well as the fourth ventricle were stained with hematoxylin-eosin (H&E) and luxol fast blue (LFB). Immunohistochemical stains using antibodies to glial fibrillary acidic protein (GFAP), vimentin and S-100 were also performed. Findings included areas of denuded and/or desquamated ependyma, rosettes in different stages of formation, vacuoles and/or pseudocysts, inflammatory changes consisting in macro- and microglial nodules in the subependymal layer, and gliosis. Chronic brain edema was seen in 4 cases. Our findings indicate that ependymal changes in sudden infant death syndrome (SIDS) cases belong to the prenatal or early postnatal period, thus providing, indirectly, a morphological substrate for the previous existence of a noxa that may also affect other CNS areas, and thus being in the position to produce cardiorespiratory control dysfunction.

Ependyma↗
PubMed1996

Pharmacokinetics of erythropoietin following single-dose subcutaneous administration in preterm infants.

The pharmacokinetics of recombinant human erythropoietin was studied in 12 very low birth weight preterm infants < 32 weeks of gestation after subcutaneous administration of 300 IU/kg at a postconceptional age of 34 (32-37) weeks and a weight of 1,505 (1330-1,740)g (median and range). The administration of recombinant human erythropoietin produced a rapid increase in serum erythropoietin levels with a peak level of 362.8 mIU/ml at 8.9 h. The area under the curve was 8,177.5 (4,597.1-15,453.0) mIU/ml/h, the absorption half-life was 5.5 (1.6-6.6) h, the elimination half-life was 7.9 (5.6-19.4) h, and the residence time was 19.6 (5.1-32.6) h (all values reflect median and range). There was no significant correlation between absorption and elimination half-life of erythropoietin and birth weight, gestational age, sex, and age and weight of the infants at the time of administration of erythropoietin. Based on absorption and elimination kinetics, the dosing interval for subcutaneous administration must not be < 48 h.

Absorption↗
PubMed1993

The interest of the neurological tissue preservation for the investigation of sudden infant death syndrome.

Sudden infant death syndrome (SIDS) is the main cause of post-natal infant mortality in developed countries with an incidence rate ranging from 1.5 to 2:1000 live births. Brainstem dysfunction of circuits which control respiration and cardiovascular stability may be involved in SIDS. Combined neuropathological and biochemical studies could elucidate some of these aspects. The relationships of these deaths to medico-legal problems could explain the scarce availability of these tissues. The need for a central SIDS tissue bank is emphasized and a protocol for the collection of CNS tissue is proposed. A detailed neuropathological study using this protocol allowed us to recognize pathological features in the CNS of 9 SIDS cases. Some features were related to the maturation of CNS, and others to possible infections. Gliosis was a common finding in most cases. The present state of SIDS investigation and results are also discussed.

Brain↗
PubMed1990

Vascular lesions in intestinal ischemia induced by cocaine-alcohol abuse: report of a fatal case due to overdose.

Intestinal ischemia induced by cocaine abuse is a rare condition. To this date, only three cases have been described. The diagnosis of bowel ischemia should be suspected whenever a cocaine addict has severe abdominal pain. A pathological examination of the resected bowel segment was performed in one case, and the diagnosis was confirmed microscopically. However, the existence of pathologic alterations of the intestinal vessels was not confirmed. Why the intestinal injury is segmental and whether it is related to the dose ingested, the administration route, or the combination of cocaine with alcohol, caffeine, or marijuana remain unclear. The authors report one fatal case associated with cocaine-alcohol overdose. The postmortem examination demonstrated the existence of segmental intestinal ischemia. Microscopic study failed to demonstrate thrombosis in the mesenteric vessels; however, we found an unusual lesion affecting the arterioles located in the intestinal submucosa of the hemorrhagic areas.

Adult↗