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Biomedical subjects

S Mullan

Publications and source records attributed to S Mullan.

At least 37 records · Page 2Linked to original sources
PubMed1980

Preliminary characterization of vasocontractile activities in erythrocytes.

The vasocontractile activities of washed red cell preparations hemolyzed by various methods were studied in vitro using isolated canine basilar arteries. Significant contractions were induced by each preparation. The maximum strength of contraction attained by the various preparations was similar. The contractile activity appeared to be dose-related, and molecular exclusion chromatography demonstrated that the activity migrated with the fraction of approximately 40,000 to 45,000 molecular weight. The vasocontractile effect of the active fraction was sustained in vitro when tested against basilar artery, but was inactive in peripheral arterial preparations. Preliminary biochemical characterization indicates that the contractile activity resides in a protein. Enzymatic digestion of the crude fraction appears to enhance the contractile activity significantly, and this observation suggests a possible mechanism for the delayed onset of ischemic symptoms encountered in the clinical situation.

Animals↗
PubMed1980

Dimethyl sulfoxide in experimental brain injury, with comparison to mannitol.

The effects of dimethyl sulfoxide therapy were studied in rhesus monkeys following a standardized occipitofrontal missile injury. This therapy resulted in substantially higher blood pressure, cerebral perfusion pressure, blood flow, and oxidative metabolism than those of a group of monkeys that had been treated similarly with mannitol, and than those of an untreated group.

Animals↗
PubMed1980

Cardiovascular effects of experimental cerebral missile injury in primates.

Ten rhesus monkeys were subjected to detailed cerebral and cardiac monitoring over a period of 90 minutes following an experimental gunshot wound. Bradycardia, decreased cardiac output, and decreased pulmonary and systemic blood pressures were observed in the presence of normal preloading (right and left atrial pressures) and afterloading (pulmonary and systemic vascular resistances). Defective cardiac output, autoregulation and cerebrovascular resistance were associated with low perfusion pressures, low cerebral blood flow, and low CMRO2.

Animals↗
PubMed1979

Treatment of carotid-cavernous fistulas by cavernous sinus occlusion.

The author reports the occlusion of 33 carotid-cavernous fistulas in 31 patients using thrombogenic techniques. In one patient the carotid artery had been occluded previously, in one it was occluded deliberately, and with 31 fistulas it was preserved. There was no mortality and virtually no morbidity.

Adolescent↗
PubMed1979

Detailed monitoring of the effects of mannitol following experimental head injury.

The experimental model of a cerebral missile injury developed by Crockard was used in three groups of Rhesus monkeys treated with mannitol. One group received mannitol 15 minutes after being injured with a BB pellet at 90 m/sec impact. Another group was wounded identically, but mannitol treatment was delayed until 1 hour after injury. The last group was wounded with the missile traveling at 180 m/sec, and mannitol was started 15 minutes after trauma. The data were contrasted with the results from the original model. After receiving mannitol, all groups showed marked improvement in mean blood pressure, cerebral perfusion pressure, cerebral blood flow, and cerebral metabolic rate of oxygen consumption out of proportion to the degree of reduction in intracranial pressure (ICP). The authors conclude that the therapeutic value of mannitol may, in some injuries, be directly related to its effects on blood flow and metabolism, as well as to its better known effects upon ICP.

Animals↗
PubMed1979

Microvascular embolization of cerebral arteriovenous malformations: A technical variation.

A useful variation of an established technique is described for embolization of cerebral arteriovenous malformations. Silastic sponge emboli that fit into No. 16, 17, and 18 stub adapters are passed through standard-sized transfemoral catheters. Of 28 treated patients, obliteration was regarded as very successful in 16. Partial success was achieved in four. Eight were regarded as failures because the reticulum was too large for these microemboli.

Adult↗
PubMed1979

Hyperemic and ischemic problems of surgical treatment of arteriovenous malformations.

Three patients with arteriovenous malformations are described who showed signs of massive hyperemia in the vascular territory of the normal brain proximal to arterial ligation. One additional patient had evidence of ischemia of the brain in the territory distal to ligation (steal), and in another both mechanisms were considered as operative hazards.

Adolescent↗
PubMed1979

Possible role of the erythrocyte in causing prolonged cerebral vasospasm.

Contractile activity of the various fractions of fresh and incubated blood was studied in vitro using the isolated canine basilar artery. Of the various fractions of fresh blood, significant contraction was induced by serum, but moderate contraction was induced by platelet-rich plasma and lysed red cells, while intact red cells and platelet-poor plasma had no significant activity. The contractions induced by serum and platelet-rich plasma were blocked by phenoxybenzamine, while those induced by lysed red cells were not. Whereas serum and platelet-rich plasma lost their contractile activity after 24 hours of incubation, lysed red cells retained activity up to 7 days after incubation. Biochemical analysis of the hemolysate by means of Sephadex column chromatography revealed that the contractile substance(s) possessed a molecular weight above 5000. These results suggest the possibility that the above substance(s) may play a role in prolonged cerebral vasospasm.

Animals↗
PubMed1978

Spontaneous carotid-cavernous fistula with fibromuscular dysplasia.

A young woman presented with a spontaneous carotid-cavernous fistula. She also had fibromuscular dysplasia of the extracranial cerebral arteries. The possible relationship of the two diseases brought up important questions concerning how to manage the patient. Treatment by obliteration of the carotid circulation on one side would be expected to increase blood flow on the other side. If the cavernous carotid artery on the second side was weakened by fibromuscular dysplasia, the increased flow might predispose to the formation of a second carotid-cavernous fistula. We first attempted to avoid surgery. When progressive symptoms occurred, the cavernous sinus was obliterated with bronze wire, thus preventing venous shunting.

Adult↗
PubMed1978

Treatment of aneurysmal hemiplegia with dopamine and mannitol.

Three patients with severe postoperative hemiplegia and one with hemiplegia following a subarachnoid hemorrhage are presented. None had hematomas. All were treated with dopamine-induced hypertension, mannitol, and large quantities of intravascular fluids. All showed a remarkable degree of clinical improvement, presumably secondary to an increase in cerebral blood flow.

Adult↗
PubMed1978

Management of 136 consecutive supratentorial berry aneurysms.

A series of 103 consecutive cases admitted to the University of Chicago Hospitals with a recently ruptured supratentorial aneurysm were medically managed by antifibrinolytic medication, and, when applicable, by hypotension, intracranial pressure control, and respiratory support. Nine patients deteriorated and died, and six rebled and died before they were judged fit for surgical treatment. Four were treated by carotid occlusion. Nine, because of refusal or medical judgment, did not have surgical treatment. Sixty-nine of these patients and a further 33, electively admitted, underwent craniotomy. In these 102 patients, there was no mortality. Seven developed postoperative hemiparesis or hemiplegia. Six recovered. One has a residual monoparesis.

Adolescent↗
PubMed1977

An experimental cerebral missile injury model in primates.

An experimental model of cerebal missile injury in rhesus monkey is described. The main objective was to create a "clean" wound devoid of bleeding from major vessels and complications due to bone fragments. There was a correlation between the wounding energy and the physiological signs, although we underestimated the actual energy level. After the right parietooccipital to right frontal injury, there was bradycardia, changes in blood pressure, and, in high-energy wounds, a marked alternation in resperation. This suggests that the missile's energy produces direct brain-stem damage, the extent of which can be related to the wounding energy.

Animals↗
PubMed1977

Physiological consequences of experimental cerebral missile injury and use of data analysis to predict survival.

The authors describe cerebrovascular and cerebral metabolic changes in monkeys, subjected to cerebral missile injury. After injury with BB pellet at 90 m/sec, there is a rapid rise in intracranial pressure (ICP), which reaches a peak 2 to 5 minutes posttrauma, and then falls to about 20 to 30 mm Hg. This, with a fall in mean blood pressure (MBP), results in a 50% reduction in cerebral perfusion pressure (CPP), Cerebral blood flow (CBF) is also reduced, although acutely there is no close relationship with (CPP). Cerebrovascular resistance falls initially and then at 30 minutes rises to very high values. Cerebral metabolic rates (CMR's) for oxygen fall after injury and remain low for the rest of the animal's life; CMR's for lactate rise immediately after injury and persists for 5 hours, then fall. After injury with a faster missile (180 m/sec), the ICP rises higher and faster, and the peak is shorter. The CCP is reduced in this injury to approximately 30 mm Hg, and only one animal survived more than 1 hour. With the conventional forms of data analysis, the length of survival after injury correlates well with MBP, ICP, and CBF, but separately they were completely unsatisfactory for prediction of an individuals prognosis. With the technique of multiple linear regression analysis, the survival of individual animals could be predicted with great accuracy. This is possible also when two postinjury parameters,CBF and MBP, are used.

Animals↗
PubMed1977

Effect of sodium nitroprusside on cerebral blood flow in conscious human beings.

Hemispheric cerebral blood flow was measured in 14 patients prior to and after the injection of sodium nitroprusside. The intracarotid method of Xenon was utilized, and flow was calculated by the flow initial technique. With a small reduction in blood pressure during the administration of sodium nitroprusside, the cerebral blood flow fell significantly by 15.9+/- 5.6%.

Adult↗