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Jeremy Heaton

Publications and source records attributed to Jeremy Heaton.

7 recordsLinked to original sources
PubMed2005

Pathophysiology of erectile dysfunction.

INTRODUCTION: Multiple regulatory systems are involved in normal erectile function. Disruption of psychological, neurological, hormonal, vascular, and cavernosal factors, individually, or in combination, can induced erectile dysfunction (ED). The contribution of neurogenic, vascular, and cavernosal factors was thoroughly reviewed by our committee, while psychological and hormonal factors contributing to ED were evaluated by other committees. AIM: To provide state of the art knowledge on the physiology of ED. METHODS: An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five different continents developed in a process over a 2-year period. Concerning the pathophysiology of ED committee, there were seven experts from five different countries. MAIN OUTCOME MEASURE: Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS: The epidemiology and classification of neurogenic ED was reviewed. The evidence for the association between vascular ED and atherosclerosis/hypercholesterolemia, hypertension and diabetes was evaluated. In addition, the pathophysiological mechanisms implicated in vascular ED were defined, including: arterial remodeling, increased vasoconstriction, impaired neurogenic vasodilatation, and impaired endothelium-dependent vasodilatation. The possible mechanisms underlying the association between chronic renal failure and ED were also evaluated as well as the evidence supporting the association of ED with various classes of medications. CONCLUSIONS: A better understanding of how diseases interfere with the physiological mechanisms that regulate penile erection has been achieved over the last few years, which helps establish a strategy for the prevention and treatment of ED.

Cardiovascular Agents↗
PubMed2004

Physiology of erectile function.

INTRODUCTION: There are numerous investigations concerning the balance and interactions between relaxant and contractile factors regulating penile smooth muscle (arterial and trabecular) tone, the determinant of penile flaccidity or erection. Enhanced knowledge of erectile physiology may improve management of men with erectile dysfunction. Aim. To provide state-of-the-art knowledge on the physiology of erectile function. METHODS: An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five continents developed in a process over a two-year period. Concerning the physiology of erectile function and pathophysiology of erectile dysfunction committee, there were seven experts from five countries. MAIN OUTCOME MEASURE: Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS: Key roles in the mechanism determining the tone of penile smooth muscle are played by the rise of the intracellular concentration of free calcium and the sensitivity of the contractile machinery to calcium, endothelial health, endothelium-derived nitric oxide, endothelium-derived hyperpolarizing factor (EDHF), neuronal nitric oxide, cyclic guanosine monophosphate-dependent protein kinase and phosphodiesterase type 5. CONCLUSIONS: A number of new mechanisms have been identified for the local regulation of penile smooth muscle contractility and therefore penile erection. Molecules participating in these pathways can be considered targets for the development of new treatments to treat erectile dysfunction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2003

Brain activation patterns during video sexual stimulation following the administration of apomorphine: results of a placebo-controlled study.

OBJECTIVES: To evaluate the in vivo effect of apomorphine sublingual versus placebo on cortical and subcortical brain activation during video sexual stimulation. METHODS: Ten patients with psychogenic erectile dysfunction and six potent controls underwent functional magnetic resonance of the brain during video sexual stimulation after the administration of either apomorphine sublingual 4mg or placebo following a randomized, double blind design. Functional magnetic resonance sessions were performed with a 7-day interval. RESULTS: In potent controls, viewing erotic versus neutral films induced bilateral activations in a network of occipito-parietal and temporal inferior regions, in dorsolateral and premotor frontal cortex, in anterior temporal limbic areas and the thalamus, which were comparable to the patient activations during erotic stimulation in the placebo condition. However, a striking difference was found in patients, who demonstrated a significant and extended activation in the cingulate gyrus, frontal mesial and frontal basal cortex, bilaterally, in comparison with potent controls. These activated neural systems were modulated by apomorphine administration which produced a picture that was similar to the one seen in potent controls. In patients with spychogenic erectile dysfunction apomorphine sublingual caused an increase in the extension of the activated networks, plus additional activation foci in subcortical and deep structures, namely in the nucleus accumbens, hypothalamus and mesencephalon: this activation was greater than that seen with placebo. Interestingly, a down-regulation in the frontal basal and temporal limbic cortex was present as shown by a decrease of functional magnetic resonance imaging signal reflecting a deactivation of these regions. CONCLUSIONS: Apomorphine significantly enhances the activation of cortical and subcortical brain function during video sexual stimulation. Patients with psychogenic erectile dysfunction may have an underlying functional abnormality of the brain acting as a previously unrecognised aetiological factor.

Administration, Sublingual↗
PubMed2002

Normal variation and influence of stress, caffeine intake, and sexual activity on uroflowmetry parameters of a middle-aged asymptomatic cohort of volunteer male urologists.

AIMS: To assess normal variations of uroflowmetry in middle-aged asymptomatic male urologists and to analyse the influence of stress, caffeine intake, and sexual activity. METHODS: Thirty-one male urologists from Quebec and Ontario were recruited for this study. All were healthy, not taking any current medications known to interfere with lower urinary tract function, and symptom-free (International Prostate Symptom Score less than 5). Each received two identical flowmeters to keep over a period of 2 weeks, one at home and one in his busiest office. Ten uroflow tracings, with a volume greater than 150 mL, were requested from each of them; five at home and five in the office. A total of 310 flows were analysed. The subjective level of stress, coffee intake, and sexual activity, in the hour before each uroflowmetrogram, was recorded, through a short self-administered questionnaire and stress visual scale. RESULTS: are presented as an average per individual. The voided volume was 331.9 mL, with an SD of 94.8 mL. The voiding time was 32.7 seconds (SD=15.5). The peak flow rate was 20.5 mL/sec (SD=3.9), the mean flow rate was 14.3 mL/sec (SD=3.0), and the time to maximum flow was 7.2 sec (SD=4.0). Subjective levels of stress did not significantly change these parameters. Uroflows were obtained with and without coffee drinking. The voided volume was 337.4 mL (SD=109.2) vs. 290.8 mL (SD=77.3) (P=0.03), and peak flow rate 19.4 mL/sec (SD=4.1) vs. 18.9 mL/sec (SD=3.1) (P=0.49), respectively. CONCLUSIONS: Uroflowmetry parameters and voided volume are highly variable in a normal asymptomatic population. Subjective stress level does not seem to have an influence on these parameters. Coffee intake significantly increases the voided volume but does not change the peak flow rate. These conclusions should be considered when using uroflowmetry parameters as an outcome measure.

Adult↗