Search PubMed⌕ Search

Biomedical subjects

M Castro

Publications and source records attributed to M Castro.

At least 127 records · Page 7Linked to original sources
PubMed1998

Simplified method for vitamin E determination in rat adipose tissue and mammary glands by high-performance liquid chromatography.

A method for vitamin E (alpha-tocopherol) measurement in rat adipose tissue and mammary gland has been developed and validated. Tissues were homogenized in ethanol-water (1:1) and extracted with n-hexane. Vitamin K1 was used as internal standard. Separation was performed by HPLC with methanol-water (96.5:3.5) as eluent in a Nucleosil C18 column (15 x 0.46 cm) at 40 degrees C. Detection was by fluorescence with excitation at 295 nm and emission at 350 nm for vitamin E and at 330 and 440 nm for vitamin K1. Standards and tissue extracts were checked for linearity giving correlation coefficients over 0.99 in a range of concentrations from 0.56 to 4.51 nmol/g in adipose tissue and from 2.18 to 17.4 nmol/g in mammary gland tissue. Intra-assay precision (R.S.D.) varied between 3 and 4%, whereas inter-assay precision was between 8 and 9%. Recoveries ranged between 95 +/- 3% and 98 +/- 11% for the two tissues, respectively. Vitamin E was measured in rats that had previously received one oral dose of this vitamin. Whereas vitamin E content in adipose tissue did not differ between late-pregnant and virgin rats, it was significantly higher in mammary gland of pregnant rats, and this difference could be related to the enhanced lipoprotein lipase activity in this group.

Adipose Tissue↗
PubMed1998

Patterns for RANTES secretion and intercellular adhesion molecule 1 expression mediate transepithelial T cell traffic based on analyses in vitro and in vivo.

Immune cell migration into and through mucosal barrier sites in general and airway sites in particular is a critical feature of immune and inflammatory responses, but the determinants of transepithelial (unlike transendothelial) immune cell traffic are poorly defined. Accordingly, we used primary culture airway epithelial cells and peripheral blood mononuclear cells to develop a cell monolayer system that allows for apical-to-basal and basal-to-apical T cell transmigration that can be monitored with quantitative immunofluorescence flow cytometry. In this system, T cell adhesion and subsequent transmigration were blocked in both directions by monoclonal antibodies (mAbs) against lymphocyte function-associated antigen 1 (LFA-1) or intercellular adhesion molecule 1 (ICAM-1) (induced by interferon gamma [IFN-gamma] treatment of epithelial cells). The total number of adherent plus transmigrated T cells was also similar in both directions, and this pattern fit with uniform presentation of ICAM-1 along the apical and basolateral cell surfaces. However, the relative number of transmigrated to adherent T cells (i.e., the efficiency of transmigration) was increased in the basal-to-apical relative to the apical-to-basal direction, so an additional mechanism was needed to mediate directional movement towards the apical surface. Screening for epithelial-derived beta-chemokines indicated that IFN-gamma treatment caused selective expression of RANTES (regulated upon activation, normal T cell expressed and secreted), and the functional significance of this finding was demonstrated by inhibition of epithelial-T cell adhesion and transepithelial migration by anti-RANTES mAbs. In addition, we found that epithelial (but not endothelial) cells preferentially secreted RANTES through the apical cell surface thereby establishing a chemical gradient for chemotaxis across the epithelium to a site where they may be retained by high levels of RANTES and apical ICAM-1. These patterns for epithelial presentation of ICAM-1 and secretion of RANTES appear preserved in airway epithelial tissue studied either ex vivo with expression induced by IFN-gamma treatment or in vivo with endogenous expression induced by inflammatory disease (i.e., asthma). Taken together, the results define how the patterns for uniform presentation of ICAM-1 along the cell surface and specific apical sorting of RANTES may serve to mediate the level and directionality of T cell traffic through epithelium (distinct from endothelium) and provide a basis for how this process is precisely coordinated to route immune cells to the mucosal surface and maintain them there under normal and stimulated conditions.

Cell Adhesion↗
PubMed1998

Traumatic spinal cord injury induces nuclear factor-kappaB activation.

Inflammatory responses are a major component of secondary injury and play a central role in mediating the pathogenesis of acute and chronic spinal cord injury (SCI). The nuclear factor-kappaB (NF-kappaB) family of transcription factors is required for the transcriptional activation of a variety of genes regulating inflammatory, proliferative, and cell death responses of cells. In this study we examined the temporal and cellular expression of activated NF-kappaB after traumatic SCI. We used a contusion model (N.Y.U. Impactor) to initiate the early biochemical and molecular changes that occur after traumatic injury to reproduce the pathological events associated with acute inflammation after SCI. The activation and cellular distribution of activated NF-kappaB was evaluated by using a monoclonal antibody that selectively recognizes activated p65 in a NF-kappaB dimer. Immunohistochemical and Western blot analyses demonstrated that NF-kappaB activation occurred as early as 0.5 hr postinjury and persisted for at least 72 hr. Using electrophoretic mobility shift assays (EMSA), we demonstrate that NF-kappaB is activated after SCI. In our immunohistochemical, Western, and EMSA experiments there are detectable levels of activated NF-kappaB in our control animals. Using double-staining protocols, we detected activated NF-kappaB in macrophages/microglia, endothelial cells, and neurons within the injured spinal cord. Colocalization of activated NF-kappaB with the NF-kappaB-dependent gene product, inducible nitric oxide synthase (iNOS), suggests functional implications for this transcription factor in the pathogenesis of acute spinal cord injury. Although there is considerable evidence for the involvement of an inflammatory reaction after traumatic SCI, this is the first evidence for the activation of NF-kappaB after trauma. Strategies directed at blocking the initiation of this cascade may prove beneficial as a therapeutic approach for the treatment of acute SCI.

Animals↗
PubMed1998

Influence of Gz and Gi2 transducer proteins in the affinity of opioid agonists to mu receptors.

The affinity displayed by different opioids to mu receptors (ORs) was determined in mouse brain membranes incubated with antibodies directed to Galpha subunits of the guanine nucleotide-binding proteins Gi2 and Gz. Assays were conducted with 10 pm 125I-Tyr27-beta-endorphin in the presence of 300 nm N, N-diallyl-Tyr-(alpha-aminoisobutyric acid)2-Phe-Leu-OH (ICI-174 864), which prevented the binding of the iodinated neuropeptide to delta-ORs. Gpp(NH)p or the preincubation of mouse brain membranes with IgGs to Gi2alpha or Gzalpha subunits, promoted reductions in the affinity exhibited by the labelled probe. The potencies of beta-endorphin, [D-Ala2,N-MePhe4,Gly-ol5]-enkephalin (DAMGO) and [D-Pen2,5]enkephalin (DPDPE) were reduced after impairing the coupling of mu-ORs to Gi2 or Gz proteins. Morphine showed a loss of affinity towards the mu-OR after preincubation of membranes with IgGs to Gzalpha subunits. However, it retained its potency after treatment with the anti-Gi2alpha IgGs. Conversely, [D-Ala2, D-Leu5]enkephalin (DADLE) and [D-Ser2, Leu5] enkephalin-Thr6 (DSLET) showed decreased affinity to mu-ORs after treatment with anti-Gi2alpha IgGs, with no noticeable change following the use of IgGs to Gzalpha subunits. The affinity exhibited by the opioid antagonists naloxone, naltrexone, naloxonazine and [Cys2,Tyr3,Orn5, Pen7 amide]somatostatin analogue (CTOP) remained unchanged after either treatment. Therefore, the affinity exhibited by opioid agonists of mu-ORs, but not antagonists, depends on the nature of the G-protein coupled to these receptors.

Animals↗
PubMed1998

[The one and a half vertical syndrome as the only evidence of bilateral thalamo-subthalamic infarction].

INTRODUCTION: The one and a half vertical syndrome consists of paralysis of upward vertical conjugated gaze and monocular paralysis of downward gaze or vice-versa. It occurs as a consequence of a mesencephalodiencephalic lesion, either unilaterally or bilaterally, due to effects on structures such as the interstitial nucleus of Cajal, posterior commissure and rostral interstitial nucleus of the medial longitudinal bundle. The arterial supply of the structures involved in the supranuclear control of vertical gaze depends on the paramedian thalamic arteries (or posterior thalamo-subthalamic arteries) and the paramedian peduncular arteries. CLINICAL CASE: We present the case of a 58 year old woman with non-insulin dependent diabetes mellitus who presented with sudden onset of diplopia of vertical gaze. On examination there was paralysis of superior vertical conjugated gaze and monocular paralysis of ocular infraversion (one and a half syndrome) with no other pathological findings. Cerebral angioresonance and Doppler studies of the territory supplied by the posterior cerebral artery were normal. CONCLUSIONS: Both unilateral and bilateral mesencephalodiencephalic infarcts usually present clinically as disorders of consciousness and of conduct (the almost universal form of presentation), involvement of the pyramidal tract, the third cranial nerves and a supranuclear disorder of vertical gaze. The unusual feature of the case we present is a bilateral thalamo-subthalamic infarct which presented solely as a one and a half vertical syndrome with no clinically apparent effect on anatomically adjacent structures. We have not found any similar cases in the literature.

Cerebral Infarction↗
PubMed1998

Capillary electrophoresis for rapid profiling of organic acidurias.

Organic acids analysis is a powerful technique in the diagnosis of inborn errors of metabolism. Clinically, patients present with severe symptoms, and early detection and appropriate treatment are often lifesaving. Most of the existing methods are based on gas chromatography in combination with mass spectrometry and require sophisticated equipment and complex sample pretreatment and derivatization. We propose a rapid, simple, and automated capillary electrophoretic method for routine analysis of urine to detect 27 organic acids related to metabolic diseases. With this method, direct measurements are performed on samples after initial centrifugation and dilution, if needed. Separation is performed in pH 6.0 phosphate buffer with methanol added as an organic modifier, -10 kV applied potential, and ultraviolet detection at 200 nm. The assay is completed in <15 min, and alternative separation conditions are proposed in case of overlapping peaks. The developed method allows the identification and quantitation of methylmalonic, pyroglutamic, and glutaric acids in samples of patients with diseases related to these acids.

Carboxylic Acids↗
PubMed1998

[Right sensory-motor syndrome as the presentation of a spontaneous cervico-thoracic epidural hematoma].

INTRODUCTION: A spontaneous cervical epidural hematoma is an infrequent cause of cord compression. The commonest clinical presentations are with paraparesia and tetraparesia. Transient hemiparesia is very rare and a sensory-motor syndrome is exceptional. CLINICAL CASE: A 38 year old man had sudden onset of spontaneous interscapular vertebral pain with bilateral root radiation. A few minutes later he started to have weakness and sensory loss in his right limbs. On clinical examination there was pain on pressure over the spinal apophyses of the T4 and T5 vertebrae, hemiparesia and hemi-hypoalgesia of the right limbs. After ten hours this had all returned to normal. MRI of the cord showed an epidural hematoma extending from C6 to T2. Coagulation studies and spinal arteriography were normal. CONCLUSIONS: The sensory motor syndrome is an unusual form of presentation of a spontaneous cervico-thoracic epidural hematoma. Root pain is a symptom of great value for orientation of a syndrome which would otherwise seem to be of central origin. The explanation for this clinical findings may be compression of both lateral cord pathways due to their particular blood distribution. Regarding therapeutic approach, this should be conservative, with close observation to see whether it will resolve spontaneously in a short period of time.

Adult↗
PubMed1998

[Clinical aspects of mitochondrial diseases].

Mitochondrial disorders are multisystemic diseases with very heterogeneous clinical manifestations. A same genetic mutation can result in distinctive clinical phenotypes and, on the other hand, distinct mutations can result in the same clinical phenotype. This article review the manifestations of the diverse clinical syndromes, their relationship with the molecular defects, and the diagnostic protocol in the investigation of a suspected mitochondrial disorder.

DNA, Mitochondrial↗
PubMed1998

Treatment and prophylaxis of Pneumocystis carinii pneumonia.

Early effective management of Pneumocystis carinii pneumonia improves outcome in patients with this disorder. Trimethoprim-sulfamethoxazole remains the agent of choice for treatment of severe P. carinii pneumonia. Pentamidine, trimethoprim-dapsone, atovaquone, and other regimens are useful in selected clinical situations. Adjunctive corticosteroids are indicated in patients with acquired immune deficiency syndrome and P. carinii pneumonia who have moderate to severe P. carinii pneumonia defined as a room air arterial PaO2 less than 70 mm Hg or an alveolar-arterial oxygen gradient of greater than 35 mm Hg. The use of trimethoprim-sulfamethoxazole, dapsone, and aerosolized pentamidine in immunocompromised patients without AIDS is also reviewed.

Adrenal Cortex Hormones↗
PubMed1997

Simultaneous determination of vitamins A and E in rat tissues by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method to determine vitamins A, Ap and E simultaneously was developed with direct extraction of vitamins from rat tissues with n-hexane and probe sonicating. The dry residue was redissolved in chloroform-methanol. Vitamins A and Ap were detected by UV-Vis and vitamin E by fluorescence. Vitamin K, used as internal standard, was detected both the UV-Vis and by fluorescence. Standards and samples were checked for linearity giving correlation coefficients that were higher than 0.99 in the concentration range of 3.1-9.4 for vitamin A, 8.2-24.7 for vitamin Ap and 0.6-1.7 nmol/g in the case of liver extracts and 0.5-3.0 nmol/g in the case of placenta. The inta-assay precision (R.S.D) varied between 1.48 and 7.25, whereas inter-assay precision was between 4.99 and 7.03. Recoveries ranged between 94 +/- 8 and 107 +/- 5%. Results from the application of this method to different rat tissues having wide range of vitamin content are presented.

Animals↗