PubMed Health⌕ Search

Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 73 records · Page 4Linked to original sources
PubMed1999

Imaging features of intraventricular melanoma.

We present the MR imaging findings in a patient with symptoms of increased intracranial pressure and a mass in the left lateral ventricle. The mass showed increased signal intensity on T1-weighted images and low signal intensity on T2-weighted images. The histologic diagnosis was that of melanoma, and detailed physical and funduscopic examinations disclosed no evidence of a primary lesion. We believe that the mass was a primary intraventricular melanoma, possibly arising from the choroid plexus, and we discuss the mechanisms that may be responsible for its occurrence in this location.

Brain Neoplasms↗
PubMed1999

Evaluation of CSF leaks: high-resolution CT compared with contrast-enhanced CT and radionuclide cisternography.

BACKGROUND AND PURPOSE: Radiologic evaluation of CSF leaks is a diagnostic challenge that often involves multiple imaging studies with the associated expense and patient discomfort. We evaluated the use of screening noncontrast high-resolution CT in identifying the presence and site of CSF rhinorrhea and otorrhea and compared it with contrast-enhanced CT cisternography and radionuclide cisternography. METHODS: We retrospectively reviewed the imaging studies and medical records of all patients who were evaluated for CSF leak during a 7-year period. Forty-two patients with rhinorrhea and/or otorrhea underwent high-resolution CT of the face or temporal bone and then had CT cisternography and radionuclide cisternography via lumbar puncture. The results of the three studies were compared and correlated with the surgical findings in 21 patients. RESULTS: High-resolution CT showed bone defects in 30 of 42 patients (71%) with CSF leak. High-resolution, radionuclide cisternography and CT cisternography did not show bone defects or CSF leak for 12 patients (29%) who had clinical evidence of CSF leak. Among the 30 patients with bone defects, 20 (66%) had positive results of their radionuclide cisternography and/or CT cisternography. For the 21 patients who underwent surgical exploration and repair, intraoperative findings correlated with the defects revealed by high-resolution CT in all cases. High-resolution CT identified significantly more patients with CSF leak than did radionuclide cisternography and CT cisternography, with a moderate degree of agreement. CONCLUSION: Noncontrast high-resolution CT showed a defect in 70% of the patients with CSF leak. No radionuclide cisternography or CT cisternography study produced positive results without previous visualization of a defect on high-resolution CT. CT cisternography and radionuclide cisternography may be reserved for patients in whom initial high-resolution CT does not identify a bone defect or for patients with multiple fractures or postoperative defects.

Adult↗
PubMed1999

Thallium-201 single-photon emission CT versus CT for the detection of recurrent squamous cell carcinoma of the head and neck.

BACKGROUND AND PURPOSE: Thallium-201 single-photon emission computed tomography (SPECT) can be used to detect primary squamous cell carcinoma (SCCA) of the head and neck. Nevertheless, there have very few studies performed to evaluate the ability of thallium-201 to depict recurrent SCCA. The purpose of this study was to compare the ability of thallium-201 SPECT with CT to enable detection of recurrent SCCA of the upper aerodigestive tract. METHODS: Thirty-three patients with a history of previously treated SCCA of the extracranial head and neck underwent thallium-201 SPECT imaging and contrast-enhanced CT. A neuroradiologist and nuclear medicine physician with knowledge of the primary site evaluated all thallium-201 studies for abnormal radiotracer uptake at the primary site. These results were correlated with histologic findings and clinical follow-up in all patients. All patients were followed up for a minimum of 2 years after completion of treatment. The McNemar test was used to determine statistical significance. RESULTS: The diagnostic accuracy of thallium-201 SPECT was as follows: sensitivity, 88%; specificity, 94%; positive predictive value, 93%; and negative predictive value, 89%. The diagnostic accuracy of CT was as follows: sensitivity, 100%; specificity, 24%; positive predictive value, 55%; and negative predictive value, 100%. The diagnostic accuracy of thallium was superior to CT (P = .01). CONCLUSION: Thallium-201 SPECT is superior to CT for differentiating recurrent tumor from post-treatment changes and may complement CT in the evaluation of previously treated SCCA of the extracranial head and neck.

Adult↗
PubMed1999

[Factors that affect DNA content analysis by flow cytometry].

DNA ploidy and cell cycle analysis by flow cytometry is used to obtain additional information about the diagnosis and prognosis of different types of cancer. However, there are several disagreements among authors about the tissue source (fresh-frozen or paraffin embedded), cellular dissociation methods (mechanical, enzymatic or other), use of different dyes, lasers, analysis software with different mathematical models and interpretation of results. A discussion about the different aspects that affect the study of DNA ploidy and cell cycle and a consensus in publications is mandatory. A strict control of analysis processes and data interpretation is also necessary.

Cell Cycle↗
PubMed1998

Association of an intracranial arteriovenous malformation and a meningioma.

A case of a simultaneously discovered arteriovenous malformation (AVM) and a meningioma is presented. A review of the literature revealed only four similar cases, but there have been 30 reports of other intracranial tumors in association with AVM. The possible mechanisms of this rare association are discussed.

Cerebral Arteries↗
PubMed1998

Changes in cultured arterial smooth muscle cells isolated from chicks upon cholesterol feeding.

We have developed cultures of smooth muscle cells (SMC) isolated from arterial hypercholesterolemic chicks (cholesterol-SMC). These cultures are suitable for the study at the molecular level of the changes in arterial SMC induced by a cholesterol diet. By using a strong dose of cholesterol (5%) for 10 d, we obtained very proliferative SMC which became foam cells after 30 d in culture. On the other hand, SMC cultures isolated from control-fed chicks had a lower growth rate than the SMC ones under the same culture conditions. DNA synthesis was fourfold greater in cholesterol-SMC than in control-SMC cultures. Intracellular cholesterol concentrations were the same in both cholesterol and control SMC during the first 14 d of culture but afterward increased in differing ways: after 20 d of culture the cholesterol-SMC increased their cholesterol content to double the control. We give here the results obtained from transmission electron microscopy, lipid analysis, proliferation studies, DNA, RNA and protein synthesis, and then discuss their implications.

Animals↗
PubMed1998

A simplified approach to the spaces of the suprahyoid neck.

CT and MR imaging permit exquisite visualization of the complex spatial anatomy of the suprahyoid neck. In spite of the large body of literature devoted to these spaces, their names and locations often are difficult to learn. By knowing the spaces and their components, the radiologist can generate an anatomically based differential diagnosis. This article presents a simplified approach to the various spaces of the suprahyoid neck and their anatomic components. Each space is discussed separately and is accompanied by a table that lists a differential diagnosis based primarily on the normal anatomic contents of the space.

Carotid Arteries↗
PubMed1998

Squamous cell carcinoma of the oropharynx and oral cavity: how imaging makes a difference.

The development of modern imaging techniques has significantly altered the treatment and management of these malignancies. Important treatment decisions that were once made intraoperatively are now made by using information from CT and MR imaging. The intent of this article is to provide the specific information that needs to be transmitted to the referring otolaryngologist or radiation oncologist and which will alter the treatment of patients with squamous cell carcinomas of the oral cavity and oropharynx.

Carcinoma, Squamous Cell↗
PubMed1998

Synergism between the effects of dietary cholesterol and coconut oil on plasma, liver and lipoprotein composition of neonatal chick.

The nature of the synergism between dietary factors and the development of atherosclerosis has not been fully defined. Our studies showed that simultaneous supplementation of 10% saturated fat rich in 12:0 and 14:0 fatty acids (coconut oil) plus 1% cholesterol to the diet produced a sharp increase of plasma cholesterol, indicating a synergic influence of both dietary constituents. This increase was especially patent in the VLDL fraction, modifying the distribution of other lipid components between the core and the surface of these particles. These changes are consistent with the atherogenic function of VLDL and its responsiveness to dietary manipulation.

Animals↗
PubMed1998

Allergic fungal sinusitis: CT findings.

PURPOSE: To determine the computed tomographic (CT) findings in patients with allergic fungal sinusitis. MATERIALS AND METHODS: The authors retrospectively reviewed CT scans and surgical and histopathologic reports in 45 patients (27 male, 18 female; age range, 8-68 years) with allergic fungal sinusitis from multiple institutions. The median age (25 years) and demographics of the patients were determined. Two head and neck radiologists together evaluated the CT scans for the presence of intrasinus high-attenuation areas, extent of sinus involvement, bone expansion and thinning, bone erosion, and extension of disease into the adjacent soft tissues. RESULTS: Allergic fungal sinusitis was more common in male patients and in patients aged 20-30 years. All patients had increased intrasinus attenuation at non-contrast material-enhanced CT. Multiple sinus involvement occurred in 43 patients. Bilateral involvement was more common than unilateral disease. Forty-four patients had complete opacification of at least one of the involved sinuses; 43 of these patients had expansion of an involved sinus, 42 had remodeling and thinning of the bony sinus walls, and 41 had erosion of the sinus wall. CONCLUSION: Allergic fungal sinusitis is a distinct clinical entity with nonspecific symptoms that may be initially suggested by the CT findings. These findings should alert the clinician to the possibility of allergic fungal sinusitis and prompt other diagnostic studies to establish the diagnosis and treatment plan.

Adolescent↗
PubMed1998

[Risk factors for psychomotor development among infants born under optimal biological conditions].

OBJECTIVE: The objective of this study is to evaluate the effect of risk factors on infant development, among low socioeconomic children born under optimal biological conditions, and who are exposed to adverse social circumstances. METHOD: Infants of both sexes, in the amount of 788, were studied and controlled prospectively at between 6 and 12 months. Their mental (MDI) and psychomotor (PDI) development was evaluated using the Bayley Scale of Infant Development. Eighteen risk factors were identified and dichotomized (high or low risk). RESULTS: Breast feeding, child temperament, maternal intelligence and home stimulation are consistently associated with lower MDI and PDI. After adjustment for co-variables, home stimulation persisted as a significant factor for explaining the variation of both developmental indexes and child sex also appears as a risk factor for motor skills development. The accumulated effect of 7 or more risk factors is associated with a significant decrease of development scores. The combination of risk categories of child temperament, maternal IQ, paternal role and home stimulation shows higher prediction power for infant development than other combinations analyzed in this study. CONCLUSION: The findings suggest than even for children born under optimal biological conditions their psychomotor development is negatively affected by the presence of simultaneous adverse environmental conditions.

Child Development↗
PubMed1998

Usefulness of proton MR spectroscopy in the evaluation of temporal lobe epilepsy.

OBJECTIVE: The purpose of our study was to compare the ability of MR spectroscopy with that of standard presurgical methods to accurately lateralize the abnormal hippocampus in a group of patients with complex partial seizures. SUBJECTS AND METHODS: Ten healthy volunteers (five male, five female) without a history of seizures, significant head trauma, or other neurologic abnormalities were chosen to participate in the study. Twelve consecutive patients (three male, nine female) having intractable temporal lobe epilepsy and undergoing presurgical evaluation for temporal lobectomy were chosen to participate in the study. The condition of all patients was refractory to medications. All patients underwent presurgical examination with interictal and video ictal electroencephalography, ictal single-photon emission computed tomography, interictal positron emission tomography, MR imaging, and neuropsychologic testing. When noninvasive data were inconclusive, depth or grid recordings were performed. The results of MR spectroscopy were also compared with postsurgical seizure control as defined by the Engel classification. RESULTS: Nine (90%) of 10 control subjects showed no significant difference in N-acetyl aspartate. One control subject showed 16% asymmetry in N-acetyl aspartate between sides. The control group showed no statistically significant differences in ratios of N-acetyl aspartate:creatine, N-acetyl aspartate:choline, or creatine:choline when comparing sides (p < .05). All 12 patients showed clearly lateralizing values identified by the index of asymmetry in N-acetyl aspartate (range, 24-93%), with a mean difference of 51% (SD, 22) (p = .01). Additionally, as a group, statistically significant indexes of asymmetry (p = .01) were seen in ratios of N-acetyl aspartate:choline (mean, 42; SD, 22%), N-acetyl aspartate:creatine (mean, 41; SD, 27), and N-acetyl aspartate:creatine + choline (mean, 42; SD, 22). Using an N-acetyl aspartate index of asymmetry of greater than 15%, which represents the mean index of asymmetry of the control subjects +/- two SDs, as our cutoff level for lateralization, the correct side was identified in all patients. When comparing both hippocampi using an asymmetry index of 15% for N-acetyl aspartate:choline + creatine, 11 (92%) of 12 were correctly lateralized. When comparing the unaffected temporal lobes between patients and control subjects, no statistically significant differences were detected in any metabolites or ratios. CONCLUSION: Our study agrees with others in showing decreased N-acetyl aspartate in the hippocampus of seizure patients when compared with control subjects. Using N-acetyl aspartate, N-acetyl aspartate:creatine, N-acetyl aspartate:choline, and N-acetyl aspartate:creatine + choline as our parameters, patients with mesial temporal lobe epilepsy were correctly lateralized with MR spectroscopy when compared with clinical consensus criteria. We consider MR spectroscopy to be complementary to MR imaging. Both studies can be performed as a single integrated examination.

Adult↗