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Biomedical subjects

M Dujovny

Publications and source records attributed to M Dujovny.

At least 199 records · Page 11Linked to original sources
PubMed1981

Metallurgical evaluation of the compatibility of surgical clips with their appliers.

Five aneurysm clips and their respective appliers (Heifetz, Vari-Angle, McFadden, Scoville, and Yasargil) were tested for the production of small metal shards that could provoke a foreign body reaction or increase the risk of a stress-corrosion failure. Pivot and Vari-Angle-McFadden clips produced numerous large shards, the Scoville clip produced a few fine shards, and the Yasargil and Heifetz clips produced none. Metal shard production due to cold metal transfer is attributed to the abrasive mechanical interaction between clips and appliers made from metals with different degrees of hardness.

Aneurysm↗
PubMed1981

The controlled delivery of thiopental and delayed cerebral revascularization.

Sodium thiopental was administered to 10 dogs following embolization of the middle cerebral artery. Its effect on the "grace period" for revascularization was investigated by performing embolectomies 6 hours later. We observed a striking reduction in the size of infarction in the animals treated with thiopental at moderate and prolonged dosage levels. The control animals treated with pentobarbital received less protection against ischemia although blood levels were similar to those of the experimental groups during the period of vascular occlusion.

Animals↗
PubMed1981

Scanning electron microscopic and X-ray energy spectrographic analysis of the inner surface of human atherosclerotic carotid plaques.

Forty specimens of carotid plaque from 30 patients who had suffered cerebrovascular accidents and 10 asymptomatic control patients were examined by light and scanning electron microscopy (SEM). The SEM revealed the finely detailed surface characteristics of the plaque including cell deposits, endothelial damage, and exposed subendothelium. X-ray energy spectrography scans revealed that 7 specimens had calcium deposits. Presurgical treatment with dipyridamole and aspirin inhibited or substantially reduced thrombus formation.

Aspirin↗
PubMed1981

[Surgical treatment of giant cerebral arteriovenous malformations].

Despite advances in the surgical management of cerebral arteriovenous malformations (AVMs), giant (AVMs (greater than 5 cm] are still considered unsuitable for direct surgical resection by most neurosurgeons. Some of the lesions are being treated with embolization, or embolization followed by surgical excision. Embolization alone is not curative and carries potential risks of neurological deficit as well involves multiple procedures. Fourteen patients with giant AVMs underwent surgical resection without prior embolization. Four of the AVMs were located primarily in the frontal lobe, two in the temporal lobe, one each in the parietal and occipital lobes, while six AVMs were localized to two lobes (temporal-occipital or parietal-occipital). Four patients had associated aneurysms with the arteriovenous malformation. Eight patients presented primarily with seizures. One of these had multiple subarachnoid hemorrhages while another had symptoms suggestive of transient vertebrobasilar ischemia. Two patients had one or more subarachnoid hemorrhages. The primary complaint in the remaining four patients was headache with other associated symptoms. The patients with AVMs involving the optic radiation have had varying degrees of visual field deficit not interfering with their function. There were no deaths and only three patients had deterioration of neurological function. One of these three had an intra cerebral hemorrhage secondary to an associated aneurysm rupture. We feel that the majority of these giant AVMs are amenable to direct surgical excision. It is difficult to asses, from the literature, the benefit of embolization prior to surgical excision in cases of giant AVMs. At least in one report dealing with combined treatment of seven giant AVMs, some authors stressed that preoperative embolization did not significantly alter the blood flow and, hence, potential of bleeding at the time of operation. Blood loss has not been a significant problem in our experience. When there is an associated aneurysm, it should be treated prior to or at the time of excision of the malformation.

Adolescent↗
PubMed1980

"Nautral" canine model of infantile hydrocephalus.

A review of the current knowledge about a variety of aspects of infantile hydrocephalus suggests that one cause of this problem is subarachnoid blood from birth trauma interacting with an anatomically immature cerebrospinal fluid-absorbing system. To test this hypothesis and to create a model that could be used to devise various methods of prophylaxis and therapy, we injected autologous blood into the cisterna magna of puppies, followed the size of their ventricles with serial computerized tomographic (CT) scans, and evaluated the scanning electron microscopic (SEM) appearance of the ventricular walls and subarachnoid space. By injecting blood until the dogs were just at the point of apnea, we obtained a 46% incidence of hydrocephalus with a 13% mortality rate. The amount of blood accepted was variable. The size of the ventricles was followed with CT scans; the time course of hydrocephalus was variable, and in some cases it resolved. SEM revealed significant regional, free cell aggregation and calcification, especially over the base of the brain, which was most marked in the animals that developed hydrocephalus. This suggests a more marked reaction or a lesser ability to clear the subarachnoid blood in those animals, although the reason for this is not clear. Possible uses for this model are suggested.

Absorption↗
PubMed1980

"True" traumatic aneurysm of the intracranial internal carotid artery: case report.

This paper reports a case of a true aneurysm of the intracranial internal carotid artery that occurred after a closed head injury. The probable etiology of this unusual lesion is discussed in respect to other partial and complete vessel wall injuries. The diagnosis of a traumatic aneurysm must be suspected when a delayed intracranial hemorrhage occurs after a head injury. The treatment of most intracranial aneurysms should be early, direct operation. Traumatic aneurysms of the internal carotid artery, however, are uniquely treacherous, and they may warrant an indirect approach when discovered soon after injury.

Brain Injuries↗
PubMed1980

Xenon- and iodine-enhanced CT of diffuse cerebral circulatory arrest.

The role of contrast-enhanced computed tomography (CT) was evaluated in three nonhuman primates with a severe cerebrovascular insult and resulting elevated intracranial pressure and diffuse circulatory arrest. In all three animals the brain vasculature did not opacify after the bolus intravenous injection of iodinated contrast media. In addition, the brain substance did not enhance although the arterial blood enhanced normally after inhalation of a high concentration of xenon. Xenon-enhanced CT scanning, like 133Xe radionuclide scanning, may be used to define the absence of generalized cerebral perfusion.

Animals↗
PubMed1980

Carotid-cavernous sinus thrombosis caused by Aspergillus fumigatus. Case report.

A case is presented of Aspergillus fumigatus granuloma involving the sphenoid sinus, sella turcica, cavernous sinus, and the internal carotid artery. The diagnosis was established by a transsphenoidal biopsy. The infection proved difficult to treat and finally remitted after chemotherapy with a combination of amphotericin B, rifampin (rifampicin), and flucytosine (5-fluorocytosine). The spectrum of aspergillosis of the central nervous system is reviewed, and difficulties in treating this infection are considered.

Adult↗
PubMed1980

Aneurysm clip testing meter.

The force that a vascular clip exerts when it is applied to a vessel is a critical factor in its safe and proper use. Permanent occlusion effected in the obliteration of aneurysms requires clip closure forces great enough to resist sliping, yet low enough not to damage the neck of the aneurysm. The authors consider the need for a device that can readily measure clip closing forces just prior to pre-surgical sterilization (immediately prior to implantation), and an instrument that meets that need is presented.

Aneurysm↗
PubMed1980

Biomechanics of vascular occlusion in neurosurgery.

Principle factors involved in effective vascular occlusion were identified and incorporated into a computer program designed to calculate the minimal occlusion force (MOF) in accordance with a modified version of Laplace's law. In vivo, the carotid arteries of 14 guinea pigs were occluded for one hour at an experimentally determined MOF or MOF + 50. A good correlation was found between the computed MOF and the experimentally determined MOF. Scanning electron microscopic (SEM) examination of the endothelium of the occluded vessels revealed extensive damage with forces greater than the MOF.

Animals↗
PubMed1979

Comparative cranial CT enhancement in a primate model of cerebral infarction.

The value of various enhancement techniques as opposed to nonenhanced CT scanning was compared in 15 baboons with cerebral infarction secondary to embolization of the left middle cerebral artery. The most prominent CT findings in infarction included an area of low absorption in the opercula--basal ganglia--centrum semiovale region and generalized lateral ventricular enlargement. Intravenous enhancement of the low-density region occurred in 25% of the animals and often obscured the preenhancement abnormality. However, a rapid bolus injection of contrast material followed by immediate consecutive CT scans (computed angiotomography) permitted prominent visualization of early-shunting veins. Delayed scanning following intrathecal enhancement better defined small infarctions that did not exhibit the usual cerebral blush. The CT imaging of inhaled xenon provides a new technique for evaluating subtle abnormalities in cerebral perfusion, even when the routine CT scan shows no abnormality.

Animals↗
PubMed1979

Pentothal protection for delay cerebral revascularization.

Thiopentone (20 mg/kg/bolus and 20 mg/kg/three hours) was effective in preventing infarction in five dogs with six hours of middle cerebral occlusion. Nine control animals sustained massive to large infarctions. Utilizing this regime therapeutic blood levels were rapidly attained for over 12 hours without side effects. From the experimental and human experience with focal cerebral ischaemia, there appears to be a finite grace period in which cerebral revascularization can be undertaken. In canine and primate models this time has been about five hours, following which the infarction process may not be reversible (Sundt et al. 1977, Laha et al. 1978). Seeking to prolong this grace period, thiopentone was selected as an ideal drug for this purpose, and its effect on the revascularized canine middle cerebral distribution was evaluated at six hours following embolectomy.

Animals↗