PubMed Health⌕ Search

Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 73 records · Page 4Linked to original sources
PubMed2000

Imaging of orofacial clefting disorders.

This article discusses the imaging and clinical features of patients with facial clefts. Patients with facial clefts are classified according to interocular distance. Typing of facial clefts is emphasized to determine which patients need to undergo not only imaging, but also imaging of the brain, to assess associated intracranial anomalies. The genetics, treatment, and implications that these clefting disorders have on the growth of the face are also discussed.

Brain↗
PubMed2000

Proton MR spectroscopy in children with bipolar affective disorder: preliminary observations.

BACKGROUND AND PURPOSE: Bipolar affective disorder (BPAD) can have its onset during childhood, but the diagnosis may be difficult to establish on the basis of clinical findings alone. Our purpose was to determine whether proton MR spectroscopy can be used to identify abnormalities in the brain of children with BPAD. METHODS: Ten children, ages 6 to 12 years, underwent clinical testing to establish the diagnosis of BPAD. After a drug washout period, all patients underwent MR spectroscopy in which a TE of 135 was used along with a single-voxel placement in both frontal and temporal lobes during a single session. Peaks from N-acetylaspartate (NAA), choline (Cho), glutamate/ glutamine (Glu/Gln), and lipids were normalized with respect to the creatine (Cr) peak to obtain ratios of values of peak areas. These data were compared with those obtained in 10 non-age-matched control subjects. To corroborate our data, five children with BPAD also underwent 2D MR spectroscopic studies of the frontal lobes with parameters similar to those used in the single-volume studies. RESULTS: All children with BPAD had elevated levels of Glu/Gln in both frontal lobes and basal ganglia relative to the control group. Children with BPAD had elevated lipid levels in the frontal lobes but not in the temporal lobes. Levels of NAA and Cho were similar for all locations in both groups. Two-dimensional MR spectroscopic studies in five children with BPAD confirmed the presence of elevated lipids in the frontal lobes. CONCLUSION: Our preliminary observations suggest that MR spectroscopy may show abnormalities in children with BPAD not found in unaffected control subjects. It remains to be established whether these abnormalities are a signature of the disease and can be used as a screening test.

Aspartic Acid↗
PubMed2000

Diffusion-weighted MR imaging offers no advantage over routine noncontrast MR imaging in the detection of vertebral metastases.

BACKGROUND AND PURPOSE: Diffusion-weighted MR imaging of the spine has been used to differentiate benign from pathologic vertebral body compression fractures. We sought to determine the utility of diffusion-weighted MR imaging in the detection of vertebral metastases and to compare it with conventional noncontrast T1- and T2-weighted MR imaging. METHODS: Fifteen patients with metastases to the spine were studied using conventional MR imaging and diffusion-weighted imaging. Blinded review of all images was undertaken, and patients were categorized according to whether they had focal or multiple lesions. The signal intensity of the lesions was compared on T1-, T2- (fast spin-echo), and diffusion-weighted images. RESULTS: In five patients with focal disease, metastases were hypointense on T1-weighted images; hypointense (n = 2), isointense (n = 1), or hyperintense (n = 2) on T2-weighted images; and hypointense (n = 3) or hyperintense (n = 2) on diffusion-weighted images with respect to presumed normal bone marrow. In 10 patients with disease in multiple sites, all lesions were hypointense on T1-weighted images; hypointense (n = 2), isointense (n = 4), hyperintense (n = 2), or mixed (n = 2) on T2-weighted images; and hypointense (n = 5), hyperintense (n = 3), or mixed (n = 2) on diffusion-weighted images with respect to presumed normal bone marrow. CONCLUSION: As used in this study, diffusion-weighted MR imaging of the spine showed no advantage in the detection and characterization of vertebral metastases as compared with noncontrast T1-weighted imaging, but was considered superior to T2-weighted imaging.

Adult↗
PubMed2000

Colloid cyst of the third ventricle: imaging-pathologic correlation.

Colloid cysts are relatively rare intracranial lesions located in the rostral aspect of the third ventricle. They may produce acute hydrocephalus, brain herniation, and lead to death. Although the clinical and imaging features of colloid cysts are well known, their etiology and the factors responsible for their imaging features continue to be a subject of debate. We present the imaging-pathologic correlation of a patient with a colloid cyst as well as data supporting the fact that the presence of cholesterol is probably responsible for the MR imaging features exhibited by some colloid cysts.

Adult↗
PubMed2000

Correlation of myo-inositol levels and grading of cerebral astrocytomas.

BACKGROUND AND PURPOSE: In a limited number of patients, the level of myo-inositol (MI), as seen by proton magnetic resonance spectroscopy (HMRS), has been shown to differ for gliomas of different histologic grades. We sought to determine if MI levels correlate with cerebral astrocytoma grade. METHODS: Five control subjects, 14 patients with low-grade astrocytoma, 10 patients with anaplastic astrocytoma, and 10 patients with glioblastoma multiforme (GBM) underwent single-volume HMRS with an echo time of 20 ms. Twenty-five patients had received surgery, chemotherapy, and/or radiation therapy previously. Using the curve-fitting program supplied by the manufacturer, peak areas for n-acetyl aspartate (NAA), choline (Cho), and MI were normalized with respect to the peak area of creatine (Cr). Ratios for MI/Cr, Cho/Cr, and NAA/Cr were obtained for each lesion and retrospectively compared with the histologic grade of the lesion. RESULTS: Levels of MI/Cr were higher (0.82 +/- 0.25) in patients with low-grade astrocytoma, intermediate (0.49 +/- 0.07) in control subjects, and lower in patients with anaplastic astrocytoma (0.33 +/- 0.16) and GBM (0.15 +/- 0.12). CONCLUSION: Our study shows a trend toward lower MI levels in the presence of anaplastic astrocytomas and GBMs compared with those of low-grade astrocytomas. MI levels may have implications in the grading of cerebral astrocytomas.

Adolescent↗
PubMed1999

Identification of polar toxicants in industrial wastewaters using toxicity-based fractionation with liquid chromatography/mass spectrometry.

An efficient and novel method for the identification of toxic compounds in industrial wastewater was developed. In the first step, the samples collected were tested for toxicity using the recently developed ToxAlert 10 system based upon luminescence inhibition of freeze-dried Vibrio fischeri. In the second step, sequential solid-phase extraction (SSPE) and liquid chromatography/mass spectrometry (LC/MS) for compound identification were employed to isolate and identify compounds in the waters. Average recoveries ranging from 72 to 95% were obtained using the SSPE methodology for ubiquitous analytes such as poly(ethylene glycol)s, nonylphenol and alcohol polyethoxylates, phenols, linear alkylbenzenesulfonates, and benzene- and naphthalenesulfonates. In the third step, all the extracts obtained after SSPE followed by LC/MS identification were tested again with the ToxAlert system. The procedure was applied to influent and effluent samples of a sewage treatment plant (STP) and to a raw tannery effluent that constitutes the main type of influent in the receiving waters of the STP. This method has shown that, despite the complexity of the untreated tannery wastewaters with an average total organic carbon (TOC) value of 1960 mg of C/L, the biological treatment of the STP eliminates compounds that inhibit luminiscence of V. fischeri. In the final step, the chemical toxicity of the tentatively identified chemicals was tested to identify the toxicants in the waters. Comparison of the toxicities of the sample, the extracts, and individual components has shown that diverse classes of pollutants were responsible for toxicity, as all fractions of toxic samples gave significant bioluminescence inhibition values. Toxicity of the two intermediate-polarity SSPE fractions was attributed to alcohol ethoxylates, nonylphenol ethoxylates, bis(2-ethylhexyl)phthalate, and linear alkylbenzenesulfonates. In the most nonpolar and most polar fractions, identification of the compounds responsible for toxicity was unclear. By the toxicity-based fractionation, followed by LC/MS methodology, it was feasible to identify between 1.4 and 7.5% of the TOC, thus expanding the number of toxicants identified in these complex wastewaters as compared to those identified by conventional gas chromatography/mass spectrometric (GC/MS) methods. When artificial water samples were reconstituted using similar concentrations of the chemicals detected in the wastewaters, nonsynergetic toxicity effects were observed for all analytes with the exception of 2,6-naphthalenedisulfonate (2,6-NPS), which promoted the bioluminescence inhibition. The toxicity-directed identification was successful for the STP's samples and showed 1400 times higher toxicity for the raw tannery wastewaters as compared to the mixed industrial and domestic wastewaters by applying the Weibull model.

Chromatography, Liquid↗
PubMed1999

MRI in 3-methylglutaconic aciduria type 1.

MRI in a young child with 3-methylglutaconic aciduria type 1 showed signal abnormalities in the basal ganglia which progressed despite successful treatment.

Amino Acid Metabolism, Inborn Errors↗
PubMed1999

Sydenham's chorea: MRI and proton spectroscopy.

We present the MRI and proton spectroscopy findings in a child with clinical diagnosis of Sydenham's chorea. MRI showed high signal in the caudate nuclei and putamina on T2-weighted images. We believe that the spectra showed an abnormality in the number and/or function of neurons, lipids from cellular breakdown (cytolytic effect of antibodies), aminoacids (related to the presence of antibodies in the neostriatum), and sugars (also related to the presence of antibodies). The spectroscopy features correlate well with the histopathology and biochemistry of this rare disorder.

Basal Ganglia↗
PubMed1999

Fungal diseases of the paranasal sinuses.

Fungal diseases of the paranasal sinuses can be categorized into the invasive and noninvasive varieties. The invasive form has been classified as acute fulminant fungal sinusitis, granulomatous invasive fungal sinusitis, and chronic invasive fungal sinusitis. The noninvasive form can be classified as the fungus ball and the allergic fungal sinusitis. The following review discusses the various types of fungal sinusitis with a special emphasis on the CT and MR imaging features.

Acute Disease↗
PubMed1999

Differential effects of dietary fat on chick plasma and liver composition and HMG-CoA reductase activity.

The comparative effects of diet supplementation with 10% saturated fat rich in 12:0 and 14:0 fatty acids (coconut oil), without and with 1% added cholesterol, and with 10% unsaturated fat rich in n-3 polyunsaturated fatty acids (menhaden oil) on cholesterol metabolism in neonatal chicks were examined to clarify the different mechanisms of their hyper- and hypolipidemic action. Supplementation of coconut oil produced a significant hypercholesterolemia after 7 days of treatment, with a similar increase in the amount of both free and esterified cholesterol. Supplementation of coconut oil plus cholesterol produced a higher increase of plasma cholesterol levels (approximately two to three times higher than those found with standard diet). However, supplementation of menhaden oil induced a significant decrease in total cholesterol after only 2 weeks of treatment. Levels of plasma triglycerides did not change by coconut oil addition to the diet, but a significant increase was observed after coconut oil plus cholesterol feeding. Menhaden oil produced a transient decrease in plasma triglycerides. Hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity did not change with coconut oil treatment. However, both coconut oil plus cholesterol and menhaden oil supplemented diets drastically decreased reductase activity after 1 week of dietary manipulation. These results show that different nutrients with the same inhibitory effect on reductase activity produced opposite effects on plasma cholesterol content, suggesting the existence of important differences in the regulatory mechanisms implied in cholesterol biosynthesis and its accumulation in plasma.

Journal Article↗
PubMed1999

Dietary fish oil reduces cholesterol and arachidonic acid levels in chick plasma and very low density lipoprotein.

The mechanisms involved in the hypolipidemic effects of fish oil have not been clearly established. This study shows that supplementation of 10% menhaden oil to the chick diet for 7 days produced a significant hypocholesterolemia and hypotriglyceridemia. Fatty acid composition of chick plasma drastically changed by the same dietary manipulation. Percentages of 20:5 and 22:6 n-3 fatty acids strongly increased, while percentages of 20:4 n-6, 18:2 n-6, and 18:1 n-9 significantly decreased. Changes observed in the relative percentages were parallel to those obtained in the amount of each fatty acid. Ratio of n-3/n-6 clearly decreased in plasma by fish oil feeding. Total cholesterol and triacylglycerol contents decreased in high density lipoprotein (HDL) but did not change in low density lipoprotein (LDL). All chemical constituents of very low density lipoprotein (VLDL) significantly decreased after the first week of menhaden oil supplementation to the diet. Similar modifications in fatty acid composition of the three lipoprotein fractions were also found. Our results suggest that the hypocholesterolemic effects of fish oil may be mediated by the depletion in VLDL synthesis and secretion into the chick plasma. On the other hand, the strong decrease found in the arachidonic acid (AA) content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.

Animals↗
PubMed1999

Efficient formation of influenza virus-like particles: dependence on the expression levels of viral proteins.

It has previously been demonstrated in this laboratory that an influenza virus-like chloramphenicol acetyltransferase (CAT) RNA could be expressed in COS-1 cells that synthesized all ten influenza A virus-encoded proteins from recombinant plasmids. It was also shown that supernatant fluids harvested from these cultures contained virus-like particles (VLPs) that could deliver an enclosed CAT RNA to MDCK cells. Here, it is shown that the levels of expression of the reporter gene in the COS-1 and/or MDCK cells can be altered drastically by modifying the concentrations of the recombinant plasmids transfected in the COS-1 cells. Thus, it was observed that overexpression of NS2 reduced CAT expression in COS-1 cells, whereas overexpression of M2 and NS1 proteins dramatically decreased transmission of the CAT RNA to the MDCK cultures. These results are discussed with reference to the roles of these proteins during virus replication. From these experiments, a ratio of transfected plasmids was found that increased the efficiency of the previously described system by 50-100-fold. Under these optimized conditions, it was demonstrated that VLPs can be formed in the absence of neuraminidase expression and that these VLPs remained aggregated to each other and to cell membranes. Moreover, it is shown that CAT RNA transmission was dependent on specific interactions of the ribonucleoprotein complex with other viral structural polypeptides. These data demonstrate the usefulness of this encapsidation-packaging system for the study of different aspects of the influenza virus life-cycle.

Animals↗
PubMed1999

Increase in alfalfa nodulation, nitrogen fixation, and plant growth by specific DNA amplification in Sinorhizobium meliloti.

To improve symbiotic nitrogen fixation on alfalfa plants, Sinorhizobium meliloti strains containing different average copy numbers of a symbiotic DNA region were constructed by specific DNA amplification (SDA). A DNA fragment containing a regulatory gene (nodD1), the common nodulation genes (nodABC), and an operon essential for nitrogen fixation (nifN) from the nod regulon region of the symbiotic plasmid pSyma of S. meliloti was cloned into a plasmid unable to replicate in this organism. The plasmid then was integrated into the homologous DNA region of S. meliloti strains 41 and 1021, which resulted in a duplication of the symbiotic region. Sinorhizobium derivatives carrying further amplification were selected by growing the bacteria in increased concentrations of an antibiotic marker present in the integrated vector. Derivatives of strain 41 containing averages of 3 and 6 copies and a derivative of strain 1021 containing an average of 2.5 copies of the symbiotic region were obtained. In addition, the same region was introduced into both strains as a multicopy plasmid, yielding derivatives with an average of seven copies per cell. Nodulation, nitrogenase activity, plant nitrogen content, and plant growth were analyzed in alfalfa plants inoculated with the different strains. The copy number of the symbiotic region was critical in determining the plant phenotype. In the case of the strains with a moderate increase in copy number, symbiotic properties were improved significantly. The inoculation of alfalfa with these strains resulted in an enhancement of plant growth.

Blotting, Southern↗