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Biomedical subjects

P J Barrionuevo

Publications and source records attributed to P J Barrionuevo.

At least 19 recordsLinked to original sources
PubMed1979

Cerebellar retraction: significance and sequelae.

Does cerebellar retraction during operations in the posterior fossa contribute to increased morbidity and mortality, and if so, what are the critical factors involved? In order to answer these questions, graded retractor pressures of 10, 20, and 30 mm Hg were applied for one hour to the cerebellar hemispheres of dogs in the sitting position. It was noted that the amount of mechanical pressure and the difference between systemic perfusion pressure and retractor pressure were important determinants of the outcome. The mechanism of damage from retractor pressure is discussed.

Animals↗
PubMed1978

Effects of contrast media on the canine subarachnoid space.

This study reports an investigation of the canine arachnoid membrane using the scanning electronmicroscope (SEM) regarding the effects of contrast material on these structures. In the normal arachnoid membrane, two basic surface patterns were observed; one fenestrated and the other embossed with parallel fibers. Ventriculography was performed on 30 mongrel dogs divided into five groups: control, air, iophendylate, meglumine iothalamate, and Metrizamide. SEM study of the arachnoid membrane from basal cisterns showed no change after air ventriculography. After contrast agents were used, macrophages appeared and fenestrations became closed with fibrin-like substance.

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PubMed1978

Protective effects of methyl prednisolone and dimethyl sulfoxide in experimental middle cerebral artery embolectomy.

Acute arterial embolism continues to be a major cause of stroke morbidity in children and young adults. Potential therapy modalities include medical management and/or cerebral revascularization. The canine middle cerebral artery (MCA) was embolized by means of a pliable cylinder, 8 mm long by 1.6 mm in diameter, via the internal carotid artery. Control and experimental embolectomies were performed 6 hours following embolization. The experimental animals were treated with either dimethyl sulfoxide (DMSO) or methyl prednisolone. In the control animals, the average area of infarction in the brain was 1.45 cu cm. The animals treated with methyl prednisolone (2 mg/kg) or DMSO (2 gm/kg) showed no infarction of the brain, whereas methyl prednisolone (30 mg/kg) did not prevent infarction.

Animals↗
PubMed1977

Ophthalmologic applications of computed tomography in nonhuman primates.

The orbital contents of 28 baboons are defined by computed tomography (CT), which provides a simple, reliable, reproducible, and accurate technique for the experimental investigation of the orbit of the nonhuman primate. This method is applied to the diagnosis of exophthalmos. The suprasellar and other basal subarachnoid cisterns are precisely delineated using intrathecal enhancement prior to CT imaging (metrizamide CT cisternography).

Animals↗
PubMed1977

The capacity for computed tomography diagnosis of cerebral infarction. An experimental study in the nonhuman primate.

The characteristic serial CT scan appearance of cerebral infarction created by embolization of the middle cerebral artery in the nonhuman primate (10 baboons) is defined. The earliest CT changes are noted by 12 to 24 hours and include generalized ventricular enlargement and a focal region of decreased absorption in the opercula-basal ganglia region. The area of diminished brain absorption is better circumscribed and of lower attenuation coefficient with increasing chronicity. Distinct hydrocephalus, unilateral exophthalmos and ventricular displacement occurred with increased intracranial pressure. Little additional diagnostic information was obtained via intravenous enhancement and care should be taken as mild enhancement may obscure an area of abnormality.

Animals↗
PubMed1977

Cranial computed tomography in the baboon: normal anatomy.

A simple, reliable, reproducible technique for performing CT scans on baboons is described. The normal morphologic appearance in 12 nonhuman primate (Papio cynocephalusl anubis) brains as defined by CT is correlated with the normal gross pathologic findings on postmortem examination. The orbital contents are also displayed with clarity equivalent to that obtained in man.

Animals↗
PubMed1976

Middle cerebral artery microneurosurgical embolectomy.

Cerebral embolism carries significant mortality and morbidity rates. Middle cerebral artery embolectomies which have been carried out in man with variable results, have been reported by different authors, In order to define a time limit for embolectomies before irreversible damage has been incurred, an experimental embolus model was used in dogs. It was observed that embolectomy carried out at 2, 3, and up to 5 hours after embolism was relatively safe and effective. Beyond 5 hours, embolectomy carried an increased risk of death and morbidity.

Animals↗
PubMedDate not supplied

Low molecular weight dextran in experimental embolectomy.

The canine middle cerebral artery (MCA) was embolized with a pliable cylinder 8 mm long by 1.6 mm in diameter via the internal carotid artery. Both control and experimental embolectomies were performed 6 hours following embolization. The experimental animals were treated with low molecular weight dextran (LMD). In the control animals, the average volume of infarction in the brain was 1.45 cm.3 In the experimental animals the average volume of infarction was 0.13 cm.3

Animals↗
PubMedDate not supplied

Scanning electron microscopic anatomy of the supratentorial basal cisterns.

Arachnoid slips from the canine supratentorial basal cisterns were excised and studied by scanning electron microscopy. The inner face of the arachnoid membrane was examined, and two fundamental surface patterns, fenestrated and embossed, were observed. The remaining fibers and microfibers were anchored to these two surface sheets.

Animals↗