Fraser W. Saunders

Topical nitroglycerin: a potential treatment for impotence.

The effect of 2 per cent nitroglycerin paste applied to the penile shaft of impotent subjects was evaluated in a placebo controlled double-blind study under laboratory conditions. After application of nitroglycerin paste or a placebo ointment base, penile tumescence was recorded through a strain gauge transducer while subjects viewed an erotic video presentation. Relative to the placebo paste the number of subjects demonstrating an increase in penile circumference after nitroglycerin (18 of 26) was significantly different than all other outcome possibilities (p less than 0.05). Noninvasive vascular assessment by ultrasonography demonstrated an increase in diameter and blood flow in the cavernous arteries after application of nitroglycerin paste. Nitroglycerin paste increases blood flow in the cavernous arteries and improves tumescence after erotic stimulation. This agent may represent a new therapy for impotence.

Topical glyceryltrinitrate causes measurable penile arterial dilation in impotent men.

The current understanding of the intracavernous changes that cause or accompany penile erections has encouraged the use of vasodilators as therapy for erectile dysfunction. An established vasodilator, glyceryltrinitrate, was selected for in vivo study because of its rapid transdermal absorption. Color coded duplex ultrasound was used to assess penile vascular response. In a large group of men with erectile dysfunction significant dilation was noted in response to a small amount of nitroglycerine paste applied to the penis. There is a measurable vasodilatory response that can be induced by synthetic nitrates in penile tissue in impotent men.

Spinal artery aneurysm

A case of a spinal artery aneurysm is presented and the relevant literature is reviewed. The pathology of this aneurysm differed from that of standard intracranial aneurysms. The coexistence of a spinal aneurysm and fibromuscular hyperplasia has not been previously reported.

Intracranial blood velocity in head injury: a transcranial ultrasound Doppler study

We report our experience monitoring head-injured patients by means of transcranial Doppler sonography. Cerebral velocity measurements and waveforms change in a consistent pattern with the existence of intracranial pressure, and it is possible to discriminate low versus high flow states. The technique, in contrast to cerebral blood flow measurement, is reliable, atraumatic, and repeatable so that diagnostic assessments can be made and the patient can be followed for therapeutic efficacy.

A computer system for continuous long-term recording, processing, and analysis of physiological data of brain injured patients in ICU settings.

The objective of this project was to assemble and test a computer-based system for continuous long-term physiological data acquisition. The system would be used to study short-term (heart rate variability) and long-term (circadian rhythms) dynamics of physiological parameters in severely brain injured patients in ICU settings. A system has been built using open-source software and the Linux operating system as the platform. The system consists of three main parts: data acquisition, processing and analysis. The system was tested in ICU and experimental settings for long periods of time (up to 10 days of non-stop recording). The system appeared to function properly and accurately. Samples of the data according to the stages of acquisition-analysis process are presented in the paper. Avenues for the system use and development are discussed.

Circadian rhythm of cerebral perfusion pressure and intracranial pressure in head injury

The aim of the study was to determine if Cerebral Perfusion Pressure (CPP) and Intracranial Pressure (ICP), in patients with head injury, has a circadian rhythm. CPP and ICP data of 13 patients were analysed using the Regressive and Iterative Cosinor methods. The Regressive Cosinor method did not detect a strong 24-hour rhythm. Therefore, the Iterative Cosinor method was used to seek rhythms with period not necessarily equal to 24 hours. Studying consecutive patient days by the Iterative cosinor method showed that rhythm is present but the rhythm period was often not 24 hours. A significant rhythm in the range of 20-30 hours was detected in eight patients for CPP (62%) and in six patients for ICP (46%). To validate the results real and surrogate time series were compared. The clinical implications of rhythmic data analysis are discussed.

Diltiazem: possible hematologic complications.

Calcium blockers are being investigated for a potential role in the prevention and treatment of cerebral vasospasm. They have been found to inhibit platelet function both with in vivo and with in vitro experiments. Clinical evidence of abnormal platelet function is sparse, however. We are presenting three patients who developed increased bleeding times that reverted to normal when the diltiazem was discontinued. This may lead to serious consequences in the presence of an unsecured aneurysm and for patients facing major intracranial surgery.

Circadian rhythm of temperature in head injury

It has been shown in a previous study that head injured patients appear to have a circadian rhythm of their body functions. This needed to be confirmed using additional data, better collection methods and analysis. Additional goals were to develop a method of detrending of physiological time series in order to improve rhythm detection when it may be hidden behind a low frequency trend and the creation of a computer system for data acquisition and analysis. The temperature data of 10 head injured patients was studied using the Iterative Cosinor method. In one case, prior to the Cosinor method, detrending of the data was used using a specially designed polynomial fitting technique. The Iterative Cosinor method showed circadian rhythms in nine out of 10 patients. After detrending, a rhythm was found in the data of the 10th patient as well. The periods of the rhythm were around, but were not equal to, 24 hours. The results show that comatose head injured patients have a circadian rhythm of their core temperature. The detection of a circadian rhythm may, in some cases, be improved by using a detrending technique. The deviation of the rhythm period from 24 hours suggests that the rhythms found in these patients are free-running, meaning that head injured patients are not synchronized with their surroundings.

Diltiazem: Does it affect vasospasm?

Calcium antagonists are being investigated for their role in preventing or ameliorating the vasospasm associated with subarachnoid hemorrhage. We have done a phase I and phase II type trial of diltiazem. No effect on spasm was documented. A tendency to increase the bleeding time was noted, but no detrimental clinical effect occurred. The rebleed rate was not changed. It appears that further study of diltiazem through a proper randomized study would not be cost- or time-effective.

Scar Prevention in Peripheral Nerve Surgery

Constriction of a peripheral nerve may precipitate a primary problem of prevent recovery from a pre-existing one. Any surgical technique to minimize subsequent constrictive scar formation would be advantageous. In this study, using rat femoral nerves, various modes of protection were evaluated. Wrapping the nerve with free fat seemed to offer the best prophylaxis.