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Biomedical subjects

M Dujovny

Publications and source records attributed to M Dujovny.

At least 217 records · Page 12Linked to original sources

Post-traumatic middle cerebral artery thrombosis.

Post-traumatic thrombosis of the middle cerebral artery (MCA) is uncommon: only 39 cases were found in the literature. In the present report, eight cases of post-traumatic MCA thrombosis are analyzed and compared with other reported cases. The symptoms can be easily confused with those of expanding intracranial hematoma. Although ancillary noninvasive diagnostic methods are helpful, cerebral angiography confirms the diagnosis. The morbidity and mortality rates are high, and treatment has been mainly supportive. The low mortality in the present study may be related to the absence of severe head or other trauma. Possible cerebral revascularization procedures are also discussed.

Adult↗

Temporary microvascular clips.

Selected commercially designated temporary clips (Acland, Biemer, Kleinert-Kutz, Variangle, and Yasargil) were applied for 1 hour to rat common carotid arteries. Scanning electron and light microscopic studies revealed varying degrees of endothelial damage. The authors believe that further improvements are needed in the design of temporary clips.

Animals↗

Minimum vascular occlusive force.

A mathematical analysis of the minimum occlusion force necessary to occlude small vessels based on the parametric influence of blood pressure, vessel diameter, clamp width, and vessel shape after clamping was performed. The results were confirmed by in vivo experimentation with 60 rat aortas (of 1.8 to 2.4 mm caliber) using a variable-force clamp gauge developed in our laboratory. Experimental and theoretical results differed by only 3 gm. Scanning electron microscopy revealed that the initial changes in the endothelium occurred in smaller radii of curvature. Increased pressure resulted in gross morphological changes across the vessel. The minimum occlusion force (as determined by the variable-force clamp gauge) produced only minimal endothelial damage.

Animals↗

Patterns of brain perfusion: dynamic computed tomography using intravenous contrast enhancement.

A representation of cerebral perfusion is obtained using cranial computed tomography following the rapid bolus injection of iodinated intravenous contrast medium. This technique permits the definition of four gross patterns of perfusion (normal, circulatory arrest, hypoperfusion, and hyperperfusion). This classification is affirmed in an experimental model of cerebral infarction in the baboon. The limitations of dynamic imaging using computed tomography are reviewed.

Animals↗

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↗

Physiologic changes in regional cerebral blood flow defined by xenon-enhanced CT scanning.

With adequate concentrations of commercially available nonradioactive xenon an enhancement of brain substance was readily demonstrated by computed tomography (CT). By performing successive CT scans at a fixed brain level following xenon inhalation, the partition coefficient and clearance of xenon as well as the regional cerebral blood flow (rCBF) could be calculated. The expected physiologic alterations in rCBF with acute cerebral infarction and changes in arterial CO2 were accurately defined by xenon-enhanced CT scanning affirming the potential future applications of this technique.

Animals↗

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.

Air↗

Lacertus fibrousus compression of the median nerve. Case report.

A 47-year-old guitar player presented with inability to use his right hand because of progressive weakness and numbness. Examination suggested compression neuropathy of the median nerve at the elbow. Exploration of the median nerve revealed compression by a tight aponeurosis of the biceps tendon. Release resulted in prompt recovery of function.

Elbow↗

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↗

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↗

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↗

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↗

Entrapment of median nerve by supracondylar process of the humerus. Case report.

The supracondylar process of the humerus has been described by anatomists and anthropologists in man and lower animals. Infrequently this process may cause compression of the median nerve. We are presenting such a case along with a brief review of the literature. Excision of the bone process led to immediate disappearance of symptoms.

Adult↗