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Biomedical subjects

A T Guay

Publications and source records attributed to A T Guay.

At least 19 recordsLinked to original sources
PubMed2003

Clomiphene increases free testosterone levels in men with both secondary hypogonadism and erectile dysfunction: who does and does not benefit?

Secondary hypogonadism is more common than primary gonadal failure and is seen in chronic and acute illnesses. Although testosterone has a role in erections, its importance in erectile dysfunction (ED) has been controversial. Hypogonadism produced by functional suppression of pituitary gonadotropins has been shown to correct with clomiphene citrate, but with a modest effect on sexual function. We wondered if longer treatment would produce improved results. A total of 178 men with secondary hypogonadism and ED received clomiphene citrate for 4 months. Sexual function improved in 75%, with no change in 25%, while significant increases in luteinizing hormone (P<0.001) and free testosterone (P<0.001) occurred in all patients. Multivariable analysis showed that responses decreased significantly with aging (P<0.05). Decreased responses also occurred in men with diabetes, hypertension, coronary artery disease, and multiple medication use. Since these conditions are more prevalent with aging, chronic disease may be a more important determinant of sexual dysfunction. Men with anxiety-related disorders responded better to normalization of testosterone. Assessment of androgen status should be accomplished in all men with ED. For those with lower than normal age-matched levels of testosterone treatment directed at normalizing testosterone with clomiphene citrate is a viable alternative to giving androgen supplements.

Aging↗
PubMed2002

Yohimbine treatment of organic erectile dysfunction in a dose-escalation trial.

Yohimbine has had questionable effects in men with organic erectile dysfunction. We conducted this study to better define the population of men responsive to yohimbine, because tobacco was thought to affect a regimen of yohimbine more than other risk factors. We measured nocturnal penile tumescence with the RigiScan monitor, hormone profiles, answers to the Florida Sexual Health Questionnaire, and clinical responses at baseline and after two different doses of yohimbine in 18 nonsmoking men with erectile dysfunction. Of the 18 men, nine (50%) were successful in completing intercourse in more than 75% of attempts. The yohimbine responders were men with less severe erectile dysfunction as manifested by improved increased rigidity on RigiScan testing, higher Florida Sexual Health Questionnaire scores, and slightly higher levels of serum testosterone. Yohimbine is an effective therapy to treat organic erectile dysfunction in some men with erectile dysfunction.

Adrenergic alpha-Antagonists↗
PubMed2002

Decreased free testosterone and dehydroepiandrosterone-sulfate (DHEA-S) levels in women with decreased libido.

A prior study has shown that premenopausal women could have decreased testosterone levels and still have regular menstrual cycles (Guay, 2001). Since ovarian function in such women was normal, the question of a possible adrenal dysfunction causing androgen deficiency was considered. If this was true, the question then arose as to whether the same defect could be seen in postmenopausal women. We studied 105 women who presented during a 6-month period of time with the chief complaint of decreased sexual desire. On subsequent testing, 74 of the women (70%) were found to have decreased total testosterone, free testosterone, and dehydroepiandrosterone sulfate (DHEA-S). Thirty-six of these women were premenopausal (ages range 24-50 years), and 38 were postmenopausal (ages range 47-78 years). All androgen levels for the women were lower than age-matched control groups found in the literature. The decreased DHEA-S levels suggest a a defect in adrenal steroidogenesis, which was seen in both premenopausal and postmenopausal women. Possible defects in regulatory mechanisms of adrenal steroidogenesis are discussed.

Adult↗
PubMed2001

Assessment of the efficacy and safety of Viagra (sildenafil citrate) in men with erectile dysfunction during long-term treatment.

Long-term efficacy and safety of sildenafil was assessed in 1008 patients with erectile dysfunction (ED) enrolled in four flexible-dose (25 - 100 mg), open-label, 36- or 52-week extension studies. After 36 and 52 weeks, 92% and 89% of patients felt that treatment with sildenafil had improved their erections. Responses to a Sexual Function Questionnaire indicated that 52 weeks of sildenafil treatment resulted in clinically significant improvements in the duration and firmness of erections, overall satisfaction with sex life, and the frequency of stimulated erections. Commonly reported adverse events (AEs) were headache, flushing, dyspepsia, and rhinitis, which were generally mild to moderate. Reports of abnormal vision were consistent with previous clinical trials. The occurrence of treatment-related cardiovascular AEs, such as hypertension, tachycardia, and palpitation, was <1%. Discontinuations due to treatment-related AEs were low (2%). Long-term therapy does not diminish the efficacy of sildenafil in patients with ED and remains well tolerated.

Administration, Oral↗
PubMed2001

Sexual dysfunction in the diabetic patient.

The incidence of diabetes mellitus is increasing at an alarming rate, and diabetic men already make up a quarter of the men in our own specific medically-oriented population of erectile dysfunction. The incidence of sexual dysfunction in men with diabetes approaches 50%, and this is only slightly lower in diabetic women. Hypertension is a frequent risk co-factor, being seen between 40% and 60% of diabetics in the literature. Obesity and hyperlipidemia are other frequent co-factors. Interestingly, these risk factors are the same as those for coronary artery disease. The final common pathway for most of these factors is endothelial cell dysfunction.

Diabetes Complications↗
PubMed2000

Male impotence.

Explore the source record for details and available documents.

Erectile Dysfunction↗
PubMed2000

Clinical experience with intraurethral alprostadil (MUSE) in the treatment of men with erectile dysfunction. A retrospective study. Medicated urethral system for erection.

OBJECTIVE: The Food and Drug Administration (USA) approved the transurethral administration of prostaglandin (alprostadil in January 1997), which had an efficacy of approximately 50% in clinical trials. We studied its effectiveness in clinical practice. METHODS: Patient and partner education was followed by an initial office trial of a medicated urethral system for erection (MUSE) after other medical risk factors were corrected during a 2- to 4-month period. The initial titration dose of alprostadil was usually 125 or 250 microg. Further titration, if needed, was instituted by the patient at home. Success was determined as the satisfactory completion of sexual intercourse in more than 66% of attempts, with a minimum of two being required. RESULTS: Two hundred and seventy patients entered the trials, and follow-up information was available in 229 (85%). The overall success rate was 56%. The dose required was 500 microg in 49.2% and 1,000 microg in 42.2%. Of the 44% in whom treatment failed, 61.4% did so because of lack of efficacy and 38.6% because of side effects (genital pain or urethral bleeding). Minor urogenital symptoms, which did not interfere with treatment, occurred in an additional 40% of patients. CONCLUSIONS: The efficacy of transurethral administration of alprostadil (56%) is higher than the initial published clinical trial data and higher than recent reported clinical experiences, although higher doses were required in our study. Men over 50 years of age, having an organic cause for erectile dysfunction, had better responses. Patient and partner education is important for successful treatment, and the in-office initial titration is an integral part of this success. Prior correction of medical risk factors may enhance the success rate.

Adult↗
PubMed1998

Asymptomatic 'big' hyperprolactinemia in two men with pituitary adenomas.

'Big' and 'big-big' hyperprolactinemia, the presence of increased serum concentrations of high molecular weight (50-60 and 150 kDa respectively) prolactin forms, has mostly been reported in women with idiopathic hyperprolactinemia and normal hypothalamic-pituitary ovarian axis function. It has been suggested that both 'big' and 'big-big' prolactin species are biologically less active than the 22 kDa form predominating in normal individuals. We report the cases of two men with pituitary adenomas who were secreting significant amounts of 'big' (50-60 kDa) prolactin documented by Sephadex G-100 column chromatography. Both patients reported normal sexual function despite high prolactin levels. Results of nocturnal rigidity and tumescence testing were normal, confirming that significant hyperprolactinemia was not interfering with either patient's sexual function. 'Big' hyperprolactinemia should thus be suspected even in male patients with prolactin-secreting pituitary adenomas who maintain adequate sexual function in the presence of high prolactin levels.

Adenoma↗
PubMed1996

Comparison of results of nocturnal penile tumescence and rigidity in a sleep laboratory versus a portable home monitor.

OBJECTIVES: To validate the results of the home penile tumescence monitor versus the sleep laboratory studies of erectile function. METHODS: We used both methods to study 18 episodes of rigidity and 19 episodes of tumescence in 10 subjects with erectile dysfunction before and after the use of an experimental vasodilating medication. RESULTS: The tumescence measurement in the sleep laboratory compared favorably with the changes in tumescence with the RigiScan portable home monitor: at the base (r = 0.70; P < 0.001), and at the tip (r = 0.84; P < 0.001). In measuring rigidity, the buckling pressure in the sleep laboratory compared favorably with the RigiScan measurements of percent average rigidity at the base (r = 0.56; P = 0.017), at the tip (r = 0.62; P = 0.006), and mean rigidity of the base and tip (r = 0.64; P = 0.004). In a comparison of the buckling pressure with the new RigiScan Plus quantitative program, there was good correlation with the rigidity activity units at the base (r = 0.70; P = 0.001) and at the tip (r = 0.72; P < 0.001). A clinical estimate of penetrable rigidity correlates with the RigiScan base rigidity of 55% to 60% and tip rigidity of about 50%. CONCLUSIONS: The portable home monitor is a viable and cost-effective clinical tool to measure nocturnal penile activity.

Aged↗
PubMed1996

Delayed diagnosis of psychological erectile dysfunction because of the presence of macroprolactinemia.

Idiopathic hyperprolactinemia can be found in men with either normal or low serum testosterone (T) levels. The explanation for the differing effects on T of similar PRL levels has not been found. Macroprolactinemia, as a clinical entity, has been reported mostly in women. These macromolecules are biologically less active and/or are transported less easily across the capillary bed than the 22-kDa molecules. Therefore, women with elevated PRL levels retain normal menses and fertility. We studied six men, aged 28-53 yr (mean, 45 yr), in whom hyperprolactinemia was initially considered to be the cause of their erectile dysfunction. PRL levels ranged from 25-92 ng/mL (normal, 2-15 ng/mL), but T and gonadotropin levels were normal, suggesting that PRL was not disrupting gonadotropin and gonadal steroid function. The results of magnetic resonance imaging studies of the pituitary gland were normal. Separation by Sephadex G-100 column chromatography showed a predominance (85-90%) of big (60 kDa) and big big ( > 150 kDa) PRL, in contrast to the predominance of 22-kDa PRL in normal subjects. Nocturnal tumescence testing was normal, supporting the diagnosis of psychogenic impotence in these subjects, and potency returned after counseling. Hence, the biologically inactive macroprolactinemia did not cause any organic derangement in erectile function. It further obscured and delayed the appropriate diagnosis and treatment of these individuals.

Adult↗
PubMed1995

Hot flushes in men with pituitary adenoma.

BACKGROUND: Hot flushes are common in menopausal women and also in men made acutely hypogonadal after orchiectomy or testicular injury. It is, however, an unusual symptom in patients with hypogonadism secondary to pituitary tumors. METHODS: In evaluating the histories of men with hypogonadal state associated with nonfunctioning pituitary macroadenoma we were struck by the presence of hot flushes in four of them. RESULTS: All four of the patients were hypogonadal with sexual dysfunction preoperatively. All had low gonadotropins and low testosterone levels with varying degrees of panhypopituitarism. All had successful transsphenoidal removal of tumors. None had endocrine improvement following surgery. All patients had improvement in sexual function and the hot flushes with administration of testosterone postoperatively. CONCLUSIONS: Hot flushes are an uncommon presentation in men with pituitary adenoma. Perhaps the symptom will become more prominent if it is specifically questioned. We postulate that the cause of the flushing is related to nonsuppressed pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus.

Adenoma↗
PubMed1995

Effect of raising endogenous testosterone levels in impotent men with secondary hypogonadism: double blind placebo-controlled trial with clomiphene citrate.

Secondary hypogonadism is not an infrequent abnormality in older patients presenting with the primary complaint of erectile dysfunction. Because of the role of testosterone in mediating sexual desire and erectile function in men, these patients are usually treated with exogenous testosterone, which, while elevating the circulating androgens, suppresses gonadotropins from the hypothalamic-pituitary axis. The response of this form of therapy, although extolled in the lay literature, has usually not been effective in restoring or even improving sexual function. This failure of response could be the result of suppression of gonadotropins or the lack of a cause and effect relationship between sexual function and circulating androgens in this group of patients. Further, because exogenous testosterone can potentially increase the risk of prostate disease, it is important to be sure of the benefit sought, i.e. an increase in sexual function. In an attempt to answer this question, we measured the hormone levels and studied the sexual function in 17 patients with erectile dysfunction who were found to have secondary hypogonadism. This double blind, placebo-controlled, cross-over study consisted of treatment with clomiphene citrate and a placebo for 2 months each. Similar to our previous observations, LH, FSH, and total and free testosterone levels showed a significant elevation in response to clomiphene citrate over the response to placebo. However, sexual function, as monitored by questionnaires and nocturnal penile tumescence and rigidity testing, did not improve except for some limited parameters in younger and healthier men. The results confirmed that there can be a functional secondary hypogonadism in men on an out-patient basis, but correlation of the hormonal status does not universally reverse the associated erectile dysfunction to normal, thus requiring closer scrutiny of claims of cause and effect relationships between hypogonadism and erectile dysfunction.

Adult↗
PubMed1995

Erectile dysfunction. Are you prepared to discuss it?

Erectile dysfunction is more common than previously thought in men older than 40 years, perhaps because contributing medical risk factors increase with age. The medical history is of prime importance in outlining these factors, the most common of which are diabetes, hypertension, and smoking. Nocturnal penile tumescence and rigidity testing with a portable home monitor may be helpful in determining whether the cause of erectile dysfunction is primarily organic or psychological. Specific therapeutic measures include sex therapy, psychotherapy, treatment for alcohol or tobacco dependency, replacement of offending medications, improved glycemic control, constriction rings, vascular surgery, androgen replacement therapy, bromocriptine mesylate (Parlodel), and thyroid, adrenal, or pituitary replacement therapy. Nonspecific therapies include yohimbine hydrochloride (Yocon), use of vacuum tumescence devices, intracorporeal injections, and penile implants.

Erectile Dysfunction↗
PubMed1992

Reproducibility in monitoring nocturnal penile tumescence and rigidity.

The evaluation of sexual dysfunction has improved with the advent of methods to test nocturnal penile tumescence that also monitor penile rigidity. Earlier techniques may not have recorded abnormal rigidity despite normal tumescence. To test the reproducibility of penile tumescence and rigidity, the results of initial and repeat tracings performed a mean of 39 days apart were compared in 17 patients (median age 62 years). Three nocturnal patterns were identified. 1) Among the 17 patients the initial penile tumescence and rigidity pattern was reproduced on repeat testing in 15. 2) Patterns that were not reproduced in the other 2 patients were explained by the ingestion of alcohol or because of a febrile illness during the period monitored. 3) Nocturnal penile rigidity and tumescence tracings from these patients reproduced previous patterns. Monitoring of nocturnal penile tumescence and rigidity is a useful and reproducible tool in the evaluation of male sexual dysfunction.

Adult↗