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Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 127 records · Page 7Linked to original sources
PubMed1996

Postmortem MR imaging of lobar cerebral infarction with pathologic and in vivo correlation.

Postmortem magnetic resonance (MR) imaging features of different types of lobar cerebral infarction are correlated with the findings in gross and histologic specimens. The postmortem findings are also correlated with in vivo findings in similar cases selected from teaching files. In acute infarction, white matter vasogenic edema leads to high signal intensity on T2-weighted images and blurring of the gray-white matter junction. Petechial hemorrhage in the cortex results in inhomogeneous signal intensity on T2-weighted images. In laminar necrosis, the hyperintense cortex on T1-weighted images is due not to hemorrhage but possibly to necrosis and the presence of lipid-laden macrophages. In subacute infarction, cortical edema and necrosis may cause the gyral pattern of enhancement. Meningeal inflammation and early fibrosis are probably responsible for meningeal enhancement. In chronic infarction, gliosis and cystic malacia are responsible for the increased signal intensity of white matter on T2-weighted images. Knowledge of the pathologic features of cerebral infarction helps in understanding the MR imaging findings.

Acute Disease↗
PubMed1996

Squamous cell carcinomas that arise in the oral cavity and tongue base: can CT help predict perineural or vascular invasion?

PURPOSE: To determine the ability to use computed tomography (CT) to predict invasion of adjacent nerves or vessels by oral cavity tumors. MATERIALS AND METHODS: Contrast material-enhanced CT scans and histopathologic reports were retrospectively reviewed in 48 patients (36 men, 12 women) aged 38-75 years who underwent gross total resection of squamous cell carcinomas arising in the tongue, the base of the tongue, and the floor of the mouth. CT criteria for diagnosis of perineural or vascular invasion were aggressive tumor margins, invasion of the sublingual space, and direct adjacency of the tumor to the enhanced lingual vasculature in the sublingual space. CT and histopathologic findings of perineural and/or vascular invasion by tumor were correlated in all patients. RESULTS: With the above criteria, CT findings predictive of perineural or vascular invasion had a sensitivity of 88%; specificity, 83%; positive predictive value, 85%; and negative predictive value, 84%. CONCLUSION: CT findings can be used to predict perineural or vascular invasion by oral cavity tumors.

Adult↗
PubMed1996

Orbital involvement by Wegener's granulomatosis: imaging findings.

OBJECTIVE: The purpose of this study was to define patterns of Wegener's granulomatosis (WG) orbital disease involvement. SUBJECTS AND METHODS: We evaluated the orbital examinations of 14 WG patients (CT for nine, MR imaging for three, and both CT and MR imaging for two) for the number of involved orbits, intraconal or extraconal location, involvement of the orbital apex, sinus involvement, bony erosion, and optic nerve compression. MR images were analyzed for signal characteristics and enhancement patterns. RESULTS: We found orbital disease to be unilateral in 12 patients (86%) and bilateral in two patients (14%) (total of 16 orbits). In 11 orbits (69%), coexistent orbital and sinus diseases with bony erosion were present. Orbital disease without sinus disease was seen in five orbits (31%). Intraorbital disease distribution was as follows: solely extraconal--seven orbits (44%) (four with involvement of muscle); intraconal with muscular involvement--one orbit (6%); combined intra- and extraconal--seven orbits (44%); and primarily orbital apex--one orbit (6%). Involvement of the apex was seen in six orbits. The WG mass was hypointense relative to orbital fat on three standard T2-weighted MR images. We saw homogeneous MR contrast enhancement in all four orbits studied on enhanced T1-weighted images. CONCLUSION: Intraorbital WG involvement is usually accompanied by paranasal sinus disease. A hypointense signal on T2-weighted MR images is helpful in suggesting the diagnosis.

Aged↗
PubMed1996

Hb Costa Rica or alpha 2 beta 2 77(EF1)His --> Arg: the first example of a somatic cell mutation in a globin gene.

We have identified a minor hemoglobin component (approximately 5%) in the blood of a healthy Costa Rican female, but not in her mother and two brothers (father not studied), that has an His --> Arg replacement at position beta 77 (Hb Costa Rica). No other amino acid replacements were observed and no beta- or gamma-chain-like peptides were present. Hb Costa Rica has abnormal stability. Sequence analyses of numerous polymerase chain reaction (PCR)-amplified segments of DNA that contain exon 2 of the beta gene failed to identify a CAC --> CGC (His --> Arg) mutation. The same was the case when cDNA was sequenced, indicating that a beta-Costa Rica-mRNA could not be detected with this procedure. Gene mapping of genomic DNA with Bg/II, BamHI, and HindIII gave normal fragments only and with the same intensity as observed for the fragments of a normal control. The quantities of the beta chain variants Hb J-Iran and Hb Fukuyama with related mutations at beta 77 vary between 30% and 45% in heterozygotes, whereas that of Hb F-Kennestone with the same His --> Arg mutation but in the G gamma-globin gene, is a high 40%-45% (as percentage of total G gamma) in a heterozygous newborn. These different observations exclude a heterozygosity of the A --> G mutation at codon beta 77, as well as a deletion comparable to that of Hbs Lepore or Kenya, or a beta-globin gene duplication, and point to a nontraditional inheritance of Hb Costa Rica. Allele-specific amplification of cDNA with appropriate primers identified the presence of a low level of mutated mRNA in the reticulocytes of the patient, which was confirmed by dotblot analysis of the same material with 32P-labeled probes. Comparable amplification products were not observed in genomic DNA. The A --> G mutation apparently occurred in a somatic cell at a relatively early stage in the development of the hematopoietic cell system, and Hb Costa Rica accumulated through rapid cell divisions in patchy areas in the bone marrow (somatic mosaicism). An unequal distribution of Hb Costa Rica over the red cells supports this possibility.

Adult↗
PubMed1996

Magnetic resonance imaging of the olfactory apparatus.

We review the normal anatomy of the olfactory system with special emphasis on its extraaxial portions. Pathological processes affecting this cranial nerve are divided into those that do not require imaging and those that do. Processes in which patients benefit from imaging, mostly with magnetic resonance, include suspected tumors and congenital abnormalities.

Brain Neoplasms↗
PubMed1996

Magnetic resonance imaging of cranial nerves IX, X, XI, and XII.

Cranial nerves IX (glossopharyngeal), X (vagus), and XI (spinal accessory) are intimately related. Therefore, for imaging purposes they are best considered as a unit rather than as individual structures. The XIth nerves are not considered true cranial nerves because they are formed by cephalic (bulbar) and caudal (spinal) divisions. The XIIth (hypoglossal) nerves arise inferiorly to the above mentioned cranial nerves and exit the skull via a different set of foramina. Because the course of these four pairs of cranial nerves extends from the base of the skull to the upper thorax, a combination of both magnetic resonance imaging (MRI) and computed tomography is needed for optimal evaluation. This article will emphasize the use of MRI when appropriate.

Accessory Nerve↗
PubMed1996

Congenital arhinia.

In a case of congenital absence of the nose, spiral axial CT showed a tiny piriform anterior aperture on the right that ended blindly. Three-dimensional reformation of CT data showed an atretic bony plate, blind-ending right nostril, absent nasal bones, and inferior continuation of the metopic suture. Noncontrast MR findings in the brain were normal.

Humans↗
PubMed1996

CT in adult supraglottitis.

We describe the CT appearance of supraglottitis and its complications in three adults. The most common CT findings were thickening of the epiglottis, aryepiglottic folds, false and true vocal cords, obliteration of the preepiglottic fa, thickening of the platysma muscle, and reticulation of the subcutaneous fat. Multiple loculated fluid-density collections consistent with abscesses were seen in one patient. Although the diagnosis of supraglottitis is generally made on the basis of the patient's history and by direct endoscopy, CT may be used to confirm the diagnosis when an adequate laryngoscopic examination cannot be performed. CT is also useful in evaluating the complications of this disorder.

Adult↗
PubMed1996

Proton MR spectroscopy of squamous cell carcinoma of the upper aerodigestive tract: in vitro characteristics.

PURPOSE: To determine the ability of in vitro high-field-strength proton MR spectroscopy to differentiate squamous cell carcinoma of the upper aerodigestive tract from uninvolved muscle. METHODS: Surgical specimens of squamous cell carcinoma arising from the upper aerodigestive tract (n = 18) and from muscle (n = 13) were examined in vitro using high-field (11 T) proton MR spectroscopy. The peak heights of choline and creatine were measured for tumor and muscle at echo times of 136 and 272. The choline/creatine (Cho/Cr) ratio was compared between tumor and normal tissue for each echo time. Student's t test was used to determine whether a significant difference existed between proton MR spectroscopic measurements of the Cho/Cr ratio for tumor and muscle. RESULTS: The mean Cho/Cr ratio was consistently higher in tumor than in muscle at all echo times; however, statistically significant differences between tumor and muscle were identified only at longer echo times (136 and 272). CONCLUSION: The Cho/Cr peak height ratio can be used to differentiate tumor from muscle in vitro (at 11 T).

Carcinoma, Squamous Cell↗
PubMed1996

MR in children with L-carnitine deficiency.

PURPOSE: To describe the MR imaging findings in five children with proved L-carnitine deficiency. METHODS: MR imaging studies (five without contrast, two with contrast) were obtained in five children (mean age, 9 years) who presented with stroke symptoms and who proved to have L-carnitine deficiency as established by serum levels. RESULTS: In three of five patients, infarctions were confined to arterial distributions; one patient had a hemorrhagic infarction in one frontoparietal region; and one patient had only nonspecific periventricular white matter T2 hyper-intensities. Serum L-carnitine levels normalized after correction; sequelae included seizures in two patients, hemiparesis in one patient, normal outcome in one patient, and death in one patient. CONCLUSION: L-Carnitine deficiency is a rare metabolic disorder leading to cerebral infarctions, as seen in our five patients, and should be considered in the differential diagnosis of children who have had a stroke, particularly when associated with hypoglycemia and myopathy.

Adolescent↗
PubMed1996

Vertical fractures of the dens.

PURPOSE: To establish the mechanism of injury that causes vertical fractures of the dens. METHODS: Over a 3-year period, 30 patients with dens fractures were seen at our institution. From these records, we identified and retrospectively reviewed the radiographs (n = 3), CT scans (n = 3), and MR images (n = 1) of three patients with vertical fractures of the dens to assess the characteristics of these fractures and other associated injuries. Medical records of these three patients were also reviewed in an attempt to elucidate the mechanism of injury. Additionally, we reviewed three cases reported in the literature and compared them with findings in our patients. RESULTS: In all patients, radiographs showed fractures involving the base of the dens (type 2), but they did not show the vertical fractures. Axial CT scans and sagittal reformations clearly showed the vertical dens fractures. One patient also had a unilateral Jefferson-type fracture. The atlantodental space was preserved in all patients. In one patient, there was posterior displacement of the fractured dens. All three patients were neurologically normal. After a 6-month period of external fixation, two patients healed adequately. CONCLUSION: Vertical dens fractures probably result from axial loading and slight extension of the head. In our cases, vertical dens fractures were accompanied by other fractures of C-1 and C-2. CT with sagittal reformations is the ideal imaging method to detect vertical dens fractures.

Adult↗
PubMed1996

[Effects of sugar cane molasses on the nutritive value of Canavalia ensiformis seeds for broiler chicks].

Three experiments were conducted to determine the efficacy of sugar cane molasses to improve performance of broiler chicks fed a diet containing 30% raw or autoclaved Canavalia ensiformis seeds (Jack beans). For this latter purpose, canavalia seeds were ground and autoclaved at 120 degrees C and 15 psi during 60 min. Day-old male chicks (Cobb x Cobb) were used throughout the study. In Experiment 1, adding 10% molasses to a control diet devoided of jack beans seeds significantly (p < 0.05) increased chick feed intake. However, neither the addition of 10% molasses nor of 5% glucose, sucrose, fructose, xylose or corn starch to the 30% raw canavalia ration allowed feed intakes similar to that shown by the control diet (Experiment 2). Broiler performance was evaluated in Experiment 3 in response to diets containing 30% raw or autoclaved jack bean meal. Ten-percent molasses was also added to both diets which along with the control diet were fed to chiks had free access to diets. Growth was depressed when the Jack bean containing diets were pair-fed to chicks. The results indicated that the use of molasses does not overcome the deleterious effects on chick performance due to the presence of 30% raw or autoclaved jack bean meal in the diets.

Animal Feed↗
PubMed1995

Baseline and follow-up MRI of the internal auditory canal after suboccipital resection of acoustic schwannoma: appearances and clinical correlations.

Prospective baseline MRI was obtained on 31 patients who had "total" removal of acoustic schwannoma 6 months to 9 years previously. Follow-up MRI was performed after 1-2 years on patients with questionable abnormalities. We found four patterns (1) internal auditory canals (IAC) with nonenhancing soft-tissue strands, possibly scars or distorted residual nerves (8); (2) IAC with marginal enhancement-reactive dura mater (16); (3) IAC with contrast-enhancing globular tissues suggesting residual or recurrent tumour (5); (4) high-signal intensity in the IAC before contrast medium administration, probably related to graft with fat/fascia/muscle (2). Prospective 1-to 2-year follow-up studies were available in 8, 5, and 1 patients in groups 2, 3, and 4 respectively. In group 2, dural enhancement remained unchanged in 5 patients and decreased in 3. In group 3 follow-up showed 1 tumour recurrence (surgically confirmed) and 4 stable abnormalities. In group 4, follow-up in 1 of the 2 patients was stable. In groups 1 and 2, the MRI features correlate well with complete tumor removal. Whether follow-up in these groups is indicated needs to be determined. In group 3 residual or recurrent tumor cannot be excluded. In group 4, grafts may prevent adequate visualization of the IAC.

Adult↗