Biomedical subjects

J M Roda

Publications and source records attributed to J M Roda.

At least 19 recordsLinked to original sources

PubMed1995

Morphometric study of focal cerebral ischemia in rats: a stereological evaluation.

An efficient, unbiased stereological method for estimating and evaluating volumetric parameters of cortical infarction is presented. Long-Evans rats were subjected to a standard procedure for achieving focal cerebral ischemia, consisting of permanent ligation of the right middle cerebral artery and temporary occlusion of both common carotid arteries. Animals were killed 24 h later by perfusion fixation and the brains were embedded in celloidin, serially sectioned at 60 microns and stained with Cresyl violet. All cases showed identifiable areas of infarction of variable extent within the territory of the right middle cerebral artery. Involvement of allocortical or subcortical structures was variable and in three cases there were small foci of infarct in the contralateral hemisphere. The absolute volumes of the infarcted tissue and of the spared cortex of both hemispheres were obtained by means of an unbiased estimator of volume based on Cavalieri's principle. The best estimate of the actual amount of infarcted cortex was found to be given by the volume ratio between the spared cortex of the right (infarcted) hemisphere and the total cortex of the left (control) hemisphere. This approach avoided the error introduced by the accompanying edema and decreased the observed interanimal variance. Sample size predictions for therapeutic-pharmacological trials show that relatively few animals would be needed using the model of ischemia and quantitative morphometry presented here to detect a 30-40% change in infarct volume.

Animals↗

PubMed1995

Reduction of infarct size by intra-arterial nimodipine administered at reperfusion in a rat model of partially reversible brain focal ischemia.

BACKGROUND AND PURPOSE: When blood flow to a brain region that has undergone an ischemic attack is reestablished, additional injury is to be expected from the reperfusion. The purpose of the study was to determine the effect of the intra-arterial injection of nimodipine at reperfusion on infarct volume in rats subjected to partially reversible focal neocortical ischemia. METHODS: Two groups of Long-Evans rats with transient bilateral common carotid artery occlusion and permanent middle cerebral artery occlusion were subjected to retrograde cannulation of the external carotid artery close to the carotid bifurcation to allow the administration of isotonic saline (group 1) or nimodipine solution (group 2) just before and during reperfusion. The estimate for the actual amount of infarcted cortex was calculated by the volume ratio between the spared cortex in the infarcted hemisphere and the total cortex of the contralateral hemisphere by means of a serological method based on the Cavalieri principle. RESULTS: The percentage of cortex that was infarcted in control rats was 63.8 +/- 3.1%, whereas nimodipine-treated rats exhibited a significantly smaller (P < .005) percentage of infarct volume (31.3 +/- 12.7%). CONCLUSIONS: Our data show that the intra-arterial injection of nimodipine just before and during reperfusion reduced neocortical infarct volume in rats subjected to partially reversible focal cerebral ischemia.

Animals↗

PubMed1995

Multiple intraspinal low-grade astrocytomas mixed with lipoma (astrolipoma). Case report.

Multiple intraspinal low-grade astrocytomas without neurofibromatosis stigmata and low-grade astrocytoma with intermingled areas of adipose tissue have not been reported previously. The authors present the case of a 48-year-old woman with a 7-month history of paraparesis. When she underwent surgery, multiple intraspinal mixed tumors made up of astrocytes mingled with adipose cells were found and excised. In this report, the authors refer to this tumor as an "astrolipoma" and discuss its characteristics.

Astrocytoma↗

PubMed1994

Spinal epidural abscess caused by Brucella: case report.

We report a case of a patient with symptoms and signs of sciatica, due to spinal epidural abscess caused by Brucella, which was diagnosed by Magnetic Resonance Image. The literature is reviewed and the radiological features, particularly magnetic resonance image findings, are analyzed.

Abscess↗

PubMed1992

Carotid blood flow in anesthetized rats: effects of carotid ligation and anastomosis.

An experimental model was developed for continuous measurement of the common carotid blood flow, in the anesthetized rat, with an electromagnetic flowmeter. The mean carotid blood flow for 41 rats averaged 3.2 +/- 0.2 ml/min at an average mean arterial pressure of 101 +/- 2.5 mm Hg and arterial pO2 of 106 +/- 3.4 mm Hg, pCO2 of 38 +/- 1.2 mm Hg, and pH of 7.36 +/- 0.02. This model allowed short- and long-term carotid hemodynamic changes to be recorded after contralateral carotid ligation or end-to-side carotid anastomosis. After ligation of the contralateral carotid, blood flow through the intact carotid increased 25% (at about 1 week) and 45% (at about 5-6 months), whereas, after anastomosis, carotid blood flow increased 76% and 89% at periods comparable to those after ligation. Arterial pressure and gases did not change throughout the experimental periods. Probable mechanisms involved in these carotid hemodynamic changes are discussed.

Anastomosis, Surgical↗

PubMed1992

Simultaneous multiple intracranial and spinal meningiomas.

We report on the case of a 50-year old woman with two intracranial meningiomas and two spinal ones. All were diagnosed at the same time and there were no signs of neurofibromatosis. Multiple meningiomas in different neural spaces are extremely rare, and even rarer is the simultaneous diagnosis of separate coincident lesions. The literature in this regard is reviewed.

Brain Neoplasms↗

PubMed1991

Prevention of cerebral ischaemic reperfusion injury by intra-arterial administration of superoxide dismutase in the rat.

An experimental test was performed to determine whether superoxide dismutase, an oxygen-free radical scavenger, reduces neurological dysfunction after transient global cerebral ischaemia. Three groups of 13 rats each were used. Group 1 served as normal controls. Groups 2 and 3 were subjected to transient global cerebral ischaemia. Before ischaemia, the right carotid bifurcation was isolated and the right external carotid artery was retrogradely cannulated, with the catheter tip positioned near the origin of the internal carotid artery. Once global cerebral ischaemia was complete, either isotonic saline (group 2) or superoxide dismutase solution (group 3) was injected through the above-mentioned catheter, before, during and after reperfusion. Consequently, the injected solutions were distributed through the circle of Willis to all of the ischaemic brain tissue. Somatosensory evoked potentials were registered in the three groups of animals and were used as a measure of neuronal function. In control animals (group 1) mean P1 latency was 8.1 msec and while the mean P1 latency was 11.9 msec in the isotonic saline treated animals (group 2), it was reduced to 8.8 msec in rats treated with the superoxide dismutase solution (group 3). P1 latency was significantly higher in group 2 than in groups 1 and 3 (P less than 0.001). As evaluated by somatosensory evoked potentials, we have concluded that the intra-arterial injection of superoxide dismutase to the ischaemic tissue improves neuronal function in rats subjected to transient global cerebral ischaemia.

Animals↗

PubMed1990

Thalamic cavernous malformation. Case report.

A 50-year-old man with a right hemiparesis was found to have a cavernous malformation in the left thalamus. The diagnosis was made using magnetic resonance (MR) imaging. The vascular malformation was totally removed by means of a transcallosal interhemispheric surgical approach, but the patient's neurological deficit worsened. The role of MR imaging in establishing the diagnosis is emphasized and other published cases with thalamic locations are reviewed.

Aphasia, Broca↗

PubMed1989

Management of cerebral mass effect lesions in multiple sclerosis.

We present three cases of multiple sclerosis (MS) with tumoural manifestation during the disease in two cases, and as the first symptom in one case. Surgery is the first option, when a new patient presents with clinical features suggestive of a brain tumour. When an MS patient presents with these symptoms, corticoid treatment should be initiated and only if mass effect in computerized tomography (CT) persists, should surgery be considered.

Adult↗

PubMed1989

Intracranial cavernous angioma in the dura.

Cavernous malformations located in the dura are rare. We present a case of a large cavernous malformation located in the anterior fossa and implanted in the dura of a pregnant woman. It showed great vascularization on an angiogram, and resembled a meningioma on computed tomographic scan. The operation was difficult because of the tumor's great vascularity and profuse bleeding.

Adult↗

PubMed1988

An increment in unilateral carotid blood flow produces cerebral aneurysms in rats.

To study the effect of haemodynamic stress on cerebral aneurysm development, three groups of adult Wistar rats were used: 1) One group with ligation of the right common carotid artery; 2) One with an end-to-side common carotid artery anastomosis and 3) Another group that was sham-operated. Blood flow through the left common carotid artery was measured with an electromagnetic flow transducer (0.85 mm in diameter) in anesthetized animals. Before the experimental intervention, the mean carotid blood flow was 2.8 +/- 0.14 ml/min. Following carotid ligation the blood flow in the patent carotid artery increased 25 +/- 5% after 7 +/- 0.3 days and 37 +/- 18% after 149 +/- 23 days; whereas following carotid anastomosis, carotid blood flow increased 102 +/- 16% after 9.6 +/- 2 days and 103 +/- 35% after 169 +/- 15 days. The sham operation did not significantly affect carotid blood flow. Control values for mean arterial pressure (102 +/- 3 mmHg) and blood gases (PaO2 = 106 +/- 3.4 mmHg, PaCO2 = 38 +/- 1.2 mmHg and pH = 7.32 +/- 0.02) were similar in the three groups of rats and did not change significantly over time after the experimental procedure. Necropsy was carried out 149 +/- 15 days after the experimental intervention. No cerebral aneurysms were found in the rats with carotid ligation or which had been sham-operated, however, three of the eight rats (p less than 0.05) with carotid anastomosis presented single aneurysms in the anterior cerebral-anterior communicating arterial complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1988

Intradural herniated dorsal disc: case report and review of the literature.

A 67-year-old man with a 1 1/2-month history of spastic paraparesis caused by a dorsal intradural disc herniation underwent surgical treatment via a posterior approach. Dorsal herniated discs are rare, and intradural dorsal disc herniations are even more infrequent. Including this case, the medical literature reviewed describes only four such cases.

Aged↗

PubMed1988

Intraventricular varix causing hemorrhage. Case report.

A case of a cerebrovascular varix located in the right lateral ventricle is reported. The patient suffered intraventricular and subarachnoid hemorrhages. The intraventricular varix was coagulated and excised.

Cerebral Angiography↗

PubMed1987

Malignant and atypical meningiomas: a reappraisal of clinical, histological, and computed tomographic features.

A series of 21 patients with atypical and malignant meningiomas is presented. Histological criteria such as high cellularity, typical and atypical mitosis, necrosis, infiltration of the underlying brain, poor differentiation, and distant metastasis define nonbenign meningiomas. Male predominance in this nonbenign group is significant when compared to a group of 205 benign meningiomas, which were also operated on. The malignant and atypical meningiomas are compared with the benign meningiomas, and special emphasis is placed on their computed tomographic features. The presence of tumor fringes (suggesting invasion of the brain substance) and intratumoral hypodense areas were both significant signs of malignancy of atypia. Radical surgical excision is still considered the treatment of choice.

Adolescent↗

PubMed1987

Neuroepithelial cyst in the optic nerve. Case report.

A 34-year-old woman presented with progressive loss of vision in her left eye of 2 months' evolution. Computerized tomography showed a hypodense lesion in the suprasellar region. At surgery a cystic lesion was found inside the optic nerve. Histological study proved it to be a neuroepithelial cyst. The pathogenesis of a neuroepithelial cyst in such an exceptional site is discussed.

Adult↗

PubMed1986

Experimental model for induction of cerebral aneurysms in rats.

Two groups of rats with induced arterial hypertension were studied. One group underwent section of the left common carotid artery with an end-to-side anastomosis of the proximal segment to the right common carotid artery. The second group was subjected to ligation of the left common carotid artery. The number of aneurysms caused by the procedure in the first group was higher, the difference being statistically significant (p less than 0.05, chi-square).

Animals↗

PubMed1985

Topographical organization of the cortical afferent connections to the cortex of the anterior ectosylvian sulcus in the cat.

The cortical afferents to the cortex of the anterior ectosylvian sulcus (SEsA) were studied in the cat, using the retrograde axonal transport of horseradish peroxidase technique. Following injections of the enzyme in the cortex of both banks, fundus and both ends (postero-dorsal and anteroventral) of the anterior ectosylvian sulcus, retrograde labeling was found in: the primary, secondary, and tertiary somatosensory areas (SI, SII and SIII); the motor and premotor cortices; the primary, secondary, anterior and suprasylvian fringe auditory areas; the lateral suprasylvian (LS) area, area 20 and posterior suprasylvian visual area; the insular cortex and cortex of posterior half of the sulcus sylvius; in area 36 of the perirhinal cortex; and in the medial bank of the presylvian sulcus in the prefrontal cortex. Moreover, these connections are topographically organized. Considering the topographical distribution of the cortical afferents, three sectors may be distinguished in the cortex of the SEsA. The cortex of the rostral two-thirds of the dorsal bank. This sector receives cortical projections from areas SI, SII and SIII, and from the motor cortex. It also receives projections from the anterolateral subdivision of LS, and area 36. The cortex of the posterior third of the dorsal bank and of the posterodorsal end. It receives cortical afferents principally from the primary, secondary and anterior auditory areas, from SI, SII and fourth somatosensory area, from the anterolateral subdivision of LS, vestibular cortex and area 36. The cortex of the ventral bank and fundus. This sulcal sector receives abundant connections from visual areas (LS, 20, posterior suprasylvian, 21 and 19), principally from the lateral posterior and dorsal subdivisions of LS. It also receives abundant connections from the granular insular cortex, caudal part of the cortex of the sylvian sulcus and suprasylvian fringe. Less abundant cortical afferents were found to arise in area 36, second auditory area and prefrontal cortex. The abundant sensory input of different modalities which appears to converge in the cortex of the anterior ectosylvian sulcus, and the consistent projection from this cortex to the deep layers of the superior colliculus, make this cortical region well suited to play a role in the control of the orientation movements of the eyes and head toward different sensory stimuli.

Afferent Pathways↗

PubMed1985

Intradural neurenteric cyst: review and discussion.

The authors describe a 5-year-old boy with a spinal neurenteric cyst without associated vertebral or other congenital malformation, causing compression of the spinal cord at C 6-7 level. He was twice treated surgically with good recovery. The pertinent literature is reviewed with reference to 43 similar reported cases.

Child, Preschool↗