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Biomedical subjects

S Minhas

Publications and source records attributed to S Minhas.

At least 19 recordsLinked to original sources
PubMed2006

Phosphodiesterase 5 inhibitors in the treatment of premature ejaculation.

To date, there is no FDA-approved therapy for premature ejaculation (PE). Recently, phosphodiesterase 5 inhibitors (PDE5-Is) have been demonstrated to have encouraging results in the treatment of PE by a few studies. The aim of this review was to assess the updated manuscripts and thereafter present the practical recommendations and possible mechanisms concerning PDE5-Is for treating PE. Using MEDLINE, we searched and assessed the peer manuscripts published from 1 January 1996 to 1 September 2005 about PDE5-Is for treating PE. The results show that the number of patients in all the reports is very few and most of the studies do not employ double-blinded and placebo-controlled tests, though they are prospective and randomized. Therefore, the results and conclusions might be biased. PDE5-Is are suggested to be used in PE with old age or associated with erectile dysfunction (ED), or to be employed alone or in combination with selective-serotonin reuptake inhibitors (SSRIs) when SSRIs fail to treat PE; behavioural therapy is proposed to be used for preventing the recurrence of PE following withdrawal of PDE5-Is. In addition, for the PE patient with a definite aetiological cause, the aetiology should be cured first, if PE still exists, followed by PDE-Is prescription. Possible mechanisms that are involved include relaxing the smooth muscles of vas deferens, seminal vesicle, prostate and urethra; decreasing the central sympathetic output; inducing peripheral analgesia; prolonging the duration of erection; and increasing confidence, the perception of ejaculatory control, overall sexual satisfaction, and decreasing the post-orgasmic refractory time to achieve a second erection after ejaculation. Well-designed multicentre studies are urgently warranted to further elucidate the efficacies and safety as well as mechanisms of PDE5-Is in the treatment of PE.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2004

The management of Peyronie's disease.

Peyronie's disease has no known cause; recent understanding of the molecular mechanisms involved and the development of an animal model will aid the medical management of early disease. The medical management of chronic disease is futile as the delicate tunical architecture cannot regenerate. Surgical correction of the penile deformity is required in a minority of patients, and a choice lies between a Nesbit operation and a plaque incision and venous patch in patients who are concerned with penile shortening.

4-Aminobenzoic Acid↗
PubMed2003

Cialis (tadalafil): a new treatment for erectile dysfunction.

Oral phosphodiesterase inhibitors have become the mainstay of treatment for erectile dysfunction. A novel and potent phosphodiesterase inhibitor, tadalafil, known as Cialis, has been introduced in the UK as an alternative to the other currently available phosphodiesterase inhibitors for the treatment of erectile dysfunction.

Carbolines↗
PubMed2003

Oral agents for erectile dysfunction.

Erectile dysfunction is a common disease affecting the lives of millions of men worldwide. Sildenafil was the first oral treatment licensed for male erectile dysfunction. However, there are now a number of other options available. In this article the currently available oral treatments are reviewed.

Administration, Oral↗
PubMed2002

The management of low-flow priapism with the immediate insertion of a penile prosthesis.

OBJECTIVE: To evaluate the outcome of patients undergoing the immediate insertion of a penile prosthesis as a treatment for acute low-flow priapism. PATIENTS AND METHODS: Eight patients presenting with low-flow priapism with a mean duration of 91 h (range 32-192) were prospectively evaluated. All had failed conservative management with the instillation of alpha-adrenergic agents, and four had already undergone shunt procedures elsewhere. Immediate management consisted of the insertion of a malleable prosthesis in six patients and an inflatable prosthesis in two. One of the malleable prostheses was subsequently changed to an inflatable device. RESULTS: There were no early complications, with all patients being satisfied with the end result, and seven having sexual intercourse. One patient developed a penile deformity after surgery, cause by fibrosis around one inflatable cylinder. All patients have maintained their penile length. CONCLUSIONS: Prolonged low-flow priapism results in a variable degree of cavernosal fibrosis and a subsequent loss of penile length. The delayed insertion of a penile prosthesis can be difficult, with high complication rates. The immediate insertion of a penile prosthesis in patients with prolonged low-flow priapism is simple and maintains penile length. This should always be offered to the patient at initial presentation, as the complication rate is low and the subsequent outcome excellent.

Adult↗
PubMed2002

Priapism: a medical emergency.

Priapism is defined as a prolonged penile erection that fails to subside despite orgasm. It is a medical emergency which should be diagnosed and treated early to preserve erectile function and avoid corporal fibrosis resulting from anoxia of the corporal tissue. Decompression is usually successful with no permanent damage if treatment is provided within 12 hours of onset.

Emergencies↗
PubMed2002

Current oral treatments for erectile dysfunction.

Erectile dysfunction (ED) is defined as the inability to achieve and maintain a penile erection adequate for satisfactory sexual intercourse. It is a significant male health problem of global dimensions affecting approximately 150 million men worldwide. A broad range of options are currently available for the management of ED. They include oral agents (phosphodiesterase 5 inhibitors, dopamine agonists and alpha-receptor blocking drugs), intracavernosal injection (papaverine, phentolamine, prostaglandin E1, vasoactive intestinal peptide), transurethral vasoactive agents (prostaglandin E1), vacuum erection devices, vascular surgery and penile prostheses. Here we review the physiology of penile erection and the currently available oral preparations. In addition, novel therapeutic strategies to improve erectile function are discussed.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2002

Oxygen free radicals and the penis.

Penile erection is dependent upon vascular smooth muscle relaxation in erectile tissue and penile arteries, the principal mediator of relaxation being nitric oxide (NO). Evidence from basic scientific studies indicates that oxidative stress mediated through the superoxide radical (superoxide) and other reactive oxygen species (ROS) may be central to impaired cavernosal function in erectile dysfunction (ED). Increased inactivation of NO by superoxide results in impaired penile NO transmission and smooth muscle relaxation. Furthermore, propagation of endothelial dysfunction by ROS may result in chronic impairment of penile vascular function, a process analogous to early atherogenesis. Indeed, ED and atherosclerosis are closely linked through shared risk factors. Given our current understanding of ED pathophysiology, antioxidants may be of benefit in both the short- and long-term. Evidence supporting the paradigm of antioxidant therapy for the prevention or treatment of ED is presented herein.

Animals↗
PubMed2001

The interaction of nitric oxide and prostaglandins in the control of corporal smooth muscle tone: evidence for production of a cyclooxygenase-derived endothelium-contracting factor.

OBJECTIVE: To investigate the interaction of endothelium-derived nitric oxide (NO) and prostaglandins (PGs) in regulating corporal smooth muscle tone in vitro. Materials and methods Strips of rabbit corpus cavernosum were mounted in organ chambers for the measurement of isometric tension. Strips were submaximally contracted with noradrenaline and concentration-response curves (CRCs) to acetylcholine (ACh) were constructed before and after treatment with 5 micromol/L atropine, 20 micromol of the cyclooxygenase inhibitor indomethacin and 10 micromol of the PGH2/thromboxane A2 receptor antagonist SQ29548. The NO synthase (NOS) inhibitors L-NG-monomethyl arginine (L-NMMA) and L-NG-nitroarginine (L-NOARG) were added to strips at tonic tension in the presence and absence of indomethacin, and after this CRCs to ACh were constructed. RESULTS: The addition of ACh to strips produced a concentration-dependent relaxation which was inhibited by atropine. Indomethacin, but not SQ29548, significantly increased relaxation to ACh. Relaxation to ACh was impaired by L-NMMA, but adding ACh to strips treated with L-NOARG resulted in contractile responses, whilst both effects were reversed by indomethacin. L-NMMA and L-NOARG led to increases in tonic tone which were unaffected by indomethacin. CONCLUSIONS: In rabbit corpus cavernosum there is a tonic release of NO which does not appear to be inhibited by a vasoconstrictor prostanoid. Endothelium-dependent relaxation to ACh results in the dual production of NO and a cyclooxygenase-derived endothelium contracting factor which acts in opposition to NO; this factor is unlikely to act on PGH2/TXA2 receptors.

Acetylcholine↗
PubMed2001

The role of nitric oxide in penile erection.

The functional state of the penis, flaccid or erect is governed by smooth muscle tone. Sympathetic contractile factors maintain flaccidity whilst parasympathetic factors induce smooth muscle relaxation and erection. It is generally accepted that nitric oxide (NO) is the principal agent responsible for relaxation of penile smooth muscle. NO is derived from two principal sources: directly from non-adrenergic non-cholinergic parasympathetic nerves and indirectly from the endothelium lining cavernosal sinusoids and blood vessels in response to cholinergic stimulation. The generation of NO from L-arginine is catalysed by nitric oxide synthase (NOS). There has been controversy over the relative prevalence of endothelial or neuronal NOS within the penis of different animal species. This review examines the role of NO in the penis in detail. Established and new treatments for erectile dysfunction whose effects are mediated via manipulation of the NO pathway are also described.

Animals↗
PubMed2001

The pathophysiological role of prostaglandins in penile erection.

Penile erection is a complex haemodynamic event and relaxation of the vascular smooth muscle of the penis is fundamental to this process. This is primarily mediated by nitric oxide (NO) produced from non-adrenergic non-cholinergic (NANC) nerves and the endothelium surrounding the corporal sinusoids. However, corporal tissue has been shown to produce a number of other vasoactive factors, including prostaglandins (PGs), which appear to not only have diverse physiological effects, but are also able to modulate the effects of other neurotransmitters, including NO.

Collagen↗