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Biomedical subjects

C W Kerber

Publications and source records attributed to C W Kerber.

78 records · Page 5Linked to original sources
PubMedDate not supplied

Iotrol, a new myelographic agent: 2. Comparative electroencephalographic evaluation by spectrum analysis.

Iotrol, a nonionic dimer isotonic with cerebrospinal fluid at 300 mg l/ml, was evaluated against metrizamide, iopamidol, and iohexol by electroencephalography (EEG) in nonanesthetized cynomolgus monkeys. Each of four monkeys was injected intrathecally with 0.5 ml/kg of 300 mg l/ml of each contrast medium. EEG was obtained before, 45 min, and 3 hr postinjection. EEG spikes, motor disturbances, convulsions, and behavior changes were observed. The EEG from C3 channel was also computer-analyzed. Average percentage differences between control and test energy content of the entire EEG and of the EEG spectrum subdivided into five frequency bands were calculated. With metrizamide, three animals suffered seizures, and all were lethargic and irritable. With iopamidol, two animals convulsed; all animals were lethargic. Transient apathy and motor disturbances were observed in the iohexol animals. No motor or behavior changes were produced by iotrol. Metrizamide and iopamidol increased the spectrum energy in all bands. Neither iohexol nor iotrol affected the EEG significantly. On the basis of these findings, iotrol holds promise as a clinical contrast material for the subarachnoid space.

Animals↗
PubMedDate not supplied

Flow in experimental berry aneurysms: method and model.

This study addresses two basic questions: What are the flow dynamics in aneurysms? Can these flows be modified to enhance retention of adhesive? Using Pyrex glass bifurcations, fluid flow was studied in a variety of aneurysms placed at varying positions around the bifurcations. Indicators injected into the slipstreams were recorded and studied both by stop-frame high-speed movie analysis and with 35 mm slides. Even at low-flow rates, a central slipstream strikes the apex of bifurcations, and may be partly responsible for the initial production of berry aneurysms. A low-pressure zone occurs at the lateral angle of bifurcations, probably explaining the formation of endovascular cushions. Flow into symmetrically placed narrow neck aneurysms did not occur. Indicator entered the aneurysm in a turbulent fashion only when there was orifice (lip) asymmetry. Both lip asymmetry and rapid flow favor intraaneurysmal turbulent flow.

Cerebrovascular Circulation↗
PubMedDate not supplied

Extra- to intracranial arterial anastomoses in therapeutic embolization: recognition and role.

Anastomoses from extra- to intracranial vessels have been shown in normal patients and, more commonly, in patients with arteriosclerotic occlusive disease, arteriovenous malformation, and postligation of the carotid artery. These channels may be of clinical importance during therapeutic embolization and probably account for two cases of complication, posterior fossa strokes that occurred after blockage of occipital arteries. By identifying these channels and then monitoring the ever-decreasing vessel acceptance of contrast agent and emboli, patient safety may be enhanced.

Adolescent↗
PubMedDate not supplied

Control and placement of intracranial microcatheters.

Balloon-tipped microcatheters allow flow-guided entry into small vessels and permit selective angiography, selective drug infusion, temporary or permanent vessel occlusion, and controlled deposition of tissue adhesives. However, active directive techniques are not usually successful with balloon microcatheters, and more passive flow-directed maneuvering must be learned. Three conditions may be encountered. In the first, the vessel to be entered is large and exits at a small angle from the parent vessel. Flow and momentum carry the microcatheter toward the goal. In the second, the abnormal vessel exists at a large angle but is larger than the continuing vessel. Inflating the balloon until it is larger than the continuing vessel will cause the flow to carry it around even sharp bends. In the third, the abnormal vessel is small and also exits at a large angle. Two balloons must then be used. The first occludes the larger mainline continuing vessel, while a second is injected; flow then carries the second around the bend.

Animals↗
PubMedDate not supplied

A teaching and research simulator for therapeutic embolization.

A teaching machine that simulates intravascular conditions found during a human therapeutic embolization has been constructed. A submersible pump drives fluid through a circuit of tubing. One limb of a Y (a vascular bifurcation) located in this circuit leads to a model arteriovenous malformation. Catheters placed in this limb may introduce embolic materials by various techniques, and those techniques may be learned and practiced under safe and stress-free conditions. Loss of an embolus into the other limb which supposedly leads to normal tissues is caught and displayed by a sieve, providing immediate feedback that a technique error has occurred.

Embolization, Therapeutic↗