Biomedical subjects

R D Lobato

Publications and source records attributed to R D Lobato.

At least 109 records · Page 6Linked to original sources

PubMed1982

Intermittent exophthalmos studied with computerized tomography. Report of two cases.

Two cases of intermittent exophthalmos are reported. In both instances, cerebral angiography and orbital venography failed to outline the lesion, which was clearly demonstrated with the aid of computerized tomography. An orbital varix was seen to be the cause of proptosis in one surgically verified case, whereas in the other this same diagnosis was suspected on the basis of the clinicoradiological findings. The etiology, clinical manifestations, and management of orbital varix are briefly discussed.

Adult↗

PubMed1981

Subependymoma of the lateral ventricle.

The case of a girl with a large cystic subependymoma of the lateral ventricle is reported. The tumor, which did not cause hydrocephalus, was attached to the wall of the frontal horn and grew out of the ventricular system extending into the anterior cranial fossa and the orbital cavity. Despite some typical features exhibited by the lesion, its true nature was not recognized during the operation. The importance of the identification of this rare benign tumor is emphasized because a radical removal may be accomplished in most cases with a very good prognosis.

Adolescent↗

PubMed1981

Giant cerebral arteriovenous malformation producing a noncommunicating hydrocephalus.

The case of a woman with a large, mixed, cerebral arteriovenous malformation mainly involving the posterior fossa and producing a noncommunicating hypertensive hydrocephalus is reported. Relief of ventricular enlargement by means of a cerebrospinal fluid shunt unexpectedly resulted in stupor and Parinauds' syndrome. These complications were completely relieved by ligating the shunt. The vascular and mechanical factors involved in the production of hydrocephalus in this patient are discussed.

Adult↗

PubMed1981

Observations on 82 patients with extradural hematoma. Comparison of results before and after the advent of computerized tomography.

A consecutive, unselected series of 82 patients with epidural hematoma treated between 1973 and 1980 is presented. Forty-one patients were managed before the advent of computerized tomography (CT) and the other 41 after this neuroradiological method was available. Mortality and disability rates which were 29.2% and 31.7% during the pre-CT period decreased to 12.1% and 19.5%, respectively, with the aid of CT scanning. This technique allowed a more rapid and accurate diagnosis of the hematomas than angiography, and defined better the presence and the evolutional changes of the associated cerebral lesions. As a consequence, surgery has been more effectively planned and executed during the CT era.

Adolescent↗

PubMed1981

Effect of pentobarbital on the reactivity of isolated human cerebral arteries.

The authors have analyzed the effect of pentobarbital (10(-5) M to 10(-3) M) on the contractile activity of isolated human cerebral arteries. Pentobarbital was found to inhibit both the spontaneous mechanical activity and the basal tone of these vessels. Relaxation induced by this drug was dose-dependent, and was more marked when the arterial tone was previously increased with noradrenalin, potassium chloride, or 5-hydroxytryptamine. In addition, pentobarbital inhibits, in a dose-dependent manner, the contractions elicited by these vasoconstrictor agents. The present findings indicate that barbiturates decrease cerebrovascular reactivity, and disagree with the hypothesis that these drugs reduce raised intracranial pressure by means of exerting a direct constrictive effect on the cerebral arteries.

Cerebral Arteries↗

PubMed1981

Effect of subarachnoid hemorrhage on contractile responses and noradrenaline release evoked in cat cerebral arteries by histamine.

This study analyzes the changes induced by subarachnoid hemorrhage (SAH) on the contractile responses and the noradrenaline release evoked in cat cerebral arteries by histamine. The dose-dependent vasoconstriction induced by histamine on the cerebral arteries of normal cats was significantly reduced by diphenhydramine and phentolamine. When SAH was produced 3 and 7 days before the experiment, the histamine-induced vasoconstriction also decreased. Thereafter, a tendency to normalization in the contractile vascular responses was observed such that in 15 days after the hemorrhage it was not significantly different from that found in controls animals. The decrease in the contractile responses to histamine provoked by SAH was similar to that seen after pretreatment with intracisternal injections of 6-hydroxydopamine. The amount of radioactivity released by histamine following preincubation with 3H-noradrenaline from the cerebral arteries of cats exposed to SAH 3, 7, and 15 days before the experiment was significantly reduced when compared with controls. Moreover, the basal level of tritium release and the radioactivity retained at the end of the experiment were also decreased after SAH. These decreases were less marked 15 days after SAH. Intracisternal injections of 6-hydroxydopamine 3, 7, and 15 days prior to the assay, and the removal of both superior cervical ganglia 15 days before the experiment, also markedly reduced these three parameters. These results indicate that histamine releases noradrenaline from cat cerebral arteries, and SAH produces a transient denervation of the perivascular adrenergic nerve endings. The inhibition of the histamine-induced vasoconstriction observed after SAH might be explained by the impairment of the indirect adrenergic mechanism involved in the overall contractile response elicited by this amine in cerebral arteries. According to the present findings, histamine does not seem to play a significant role in the production of the cerebral vasospasm occurring after SAH.

Animals↗

PubMed1981

Hydrocephalus in cerebral cysticercosis. Pathogenic and therapeutic considerations.

The cases of 11 patients with hydrocephalus secondary to cerebral cysticercosis are analyzed. Most of the patients had suffered from epilepsy before they developed hydrocephalic symptoms, and computerized tomography showed that infestation of the parenchyma coexisted with ventricular or cisternal colonization. In four cases, the parasitic vesicles compromised cerebrospinal fluid (CSF) flow in the ventricular system, resulting in internal hydrocephalus. Communicating hydrocephalus, caused by the presence of Cysticercus larvae in the basal cisterns (Cysticercus racemosus), or by the occurrence of a chronic basal meningitis, or both, developed in seven more patients. Changes in CSF pressure were related to the number and location of the cysts and to the leptomeningeal inflammatory reactions evoked by them. The majority of patients presented with a chronic and relatively normotensive hydrocephalus. All patients except one had identifiable ventricular or cisternal Cysticercus larvae; these patients were treated with open removal of the cysts, and did well. However, most of them had impairment of CSF flow through the basal cisterns and required permanent CSF shunting. Communicating hydrocephalus due to leptomeningeal scarring was also successfully managed with extracranial shunting. Epilepsy was controlled with anticonvulsant therapy. Although good lasting results may be obtained with aggressive treatment of neurocysticercosis, patients are liable to relapse because surgery is only palliative in most instances.

Adult↗

PubMed1980

Chronic adult hydrocephalus due to uncommon causes.

The authors report on four unusual cases of chronic adult hydrocephalus extracted from a large personal series of patients with hydrocephalic dementia. A syndrome resembling that of normal pressure hydrocephalus was due to the following aetiologies in these patients: Paget's disease of the skull, unruptured cerebral arteriovenous malformation, colloid cyst of the third ventricle, and cerebromeningeal cysticercosis. All these patients exhibited disturbances in cerebrospinal fluid dynamics at the time of study, and were considerably improved by CSF shunting. The value of the continuous CSF pressure monitoring and the constant infusion test in selecting patients with chronic hydrocephalus for shunt therapy is emphasized.

Adult↗

PubMed1980

Epidural haematoma of the posterior fossa with delayed operation. Report of a "chronic" case.

A case of chronic epidural haematoma of the posterior fossa is reported. The lesion was studed with cerebral angiography and computed tomography. The patient was under observation for two weeks before the extradural clot was removed. The membrane surrounding the haematoma was examined histologically. The importance of computed tomography in the diagnosis of traumatic lesions of the posterior fossa is emphasized.

Brain Injuries↗

PubMed1980

Effect of experimental subarachnoid hemorrhage on the adrenergic innervation of cerebral arteries.

The effect of subarachnoid hemorrhage (SAH) on the adrenergic innervation of cat cerebral arteries was analyzed. Intracisternal injections of autologous blood reduced the noradrenaline content from the perivascular nerves. Dopamine beta-hydroxylase and the uptake of 3H-noradrenaline were also decreased. These changes returned to normal in a period of 2 to 3 weeks after the SAH. Superior cervical ganglionectomy and intracisternal injections of 6-hydroxydopamine also reduced these three parameters. It is suggested that SAH induces a transient adrenergic denervation of the cerebral arteries that might be involved in the production of the chronic cerebral vasospasm.

Animals↗

PubMed1980

Cerebrovascular reactivity to noradrenaline and serotonin following experimental subarachnoid hemorrhage.

This study analyzes the time course of the changes induced by subarachnoid hemorrhage (SAH) in the sensitivity of cat cerebral arteries to noradrenaline and serotonin. Cerebral arteries to noradrenaline and serotonin. Cerebral arteries displayed a supersensitivity to these amines, which was most marked 3 days after the experiment and then gradually disappeared. The supersensitivity to serotonin was greater and longer than the response to noradrenaline. The increase in the vascular contractile response induced by SAH was similar to that seen after superior cervical ganglionectomy or intracisternal injections of 6-hydroxydopamine. It is suggested that supersensitivity to noradrenaline and serotonin induced by SAH may be involved in the production of chronic cerebral vasospasm.

Animals↗

PubMed1979