Sex difference in serum luteinizing hormone postgonadectomy in the rat: role of gamma-aminobutyric acid-ergic inhibition

In adult male rats, serum luteinizing hormone (LH) rises within a few hours of castration. By contrast, in adult female rats, serum LH does not increase reliably until 4-6 d after ovariectomy. The release of gonadotropin-releasing hormone (GnRH) declines in female rats postovariectomy, suggesting an increase in inhibition of the release of GnRH. We investigated whether differences in gamma-aminobutyric acid (GABA)-ergic transmission, which inhibits GnRH release, accounts for the sex difference in the response of serum LH to gonadectomy. We examined the effects of GABA-A receptor antagonist bicuculline methiodide (BMI), GABA-B receptor antagonist phaclofen, and transaminase inhibitor aminooxyacetic acid (AOAA), injected subcutaneously, on the postgonadectomy rise in LH. AOAA prevented the postcastration rise in male rats (p < 0.05). Female rats treated with BMI, phaclofen, or both BMI and phaclofen (p < 0.05) showed a significant increase in LH postovariectomy. BMI had no effect in male rats. GnRH antagonist blocked the BMI-induced increase in serum LH. We conclude that the delay in the rise of serum LH in female rats postovariectomy is at least partly owing to GABAergic inhibition of the release of GnRH.

Prevalence of lower urinary tract symptoms and self-reported diagnosed 'benign prostatic hyperplasia', and their effect on quality of life in a community-based survey of men in the UK

OBJECTIVES

To assess the prevalence of lower urinary tract symptoms (LUTS) in a community-based population in the UK, to measure the impact of these symptoms on quality of life and health status in men with self-reported 'benign prostatic hyperplasia' ('BPH'), and to evaluate health-seeking behaviour in this population.

SUBJECTS AND METHODS

A postal survey was distributed to an age-stratified random sample of 1500 men aged 50 years or older from throughout England, Scotland and Wales. The self-administered survey included: demographic questions; the EuroQoL (EQ-5D) instrument, consisting of a health-status index questionnaire and a visual analogue scale (VAS) on which participants rated their current health status; the International Prostate Symptom Score (IPSS) questionnaire; and a questionnaire assessing the participants' health-seeking behaviour and awareness of BPH.

RESULTS

Responses to the survey were received from 1115 (74%) of the 1500 men. Overall, 41% (450/ 088) had an IPSS of > or =8, indicating moderate-to-severe LUTS, yet only 196 men (18%) reported that they had been diagnosed with 'BPH'. Both quality of life (as measured by the EQ-5D) and general health status (as measured by the VAS) decreased as urinary symptom severity increased, and the greater the severity, the more men who reported a problem with mobility, self-care, usual activity, pain/discomfort, and anxiety/depression (the five domains of the EQ-5D). The possibility of symptoms worsening appeared to be the key determinant in the respondents' decisions to consult a medical professional for their LUTS. Less than 11% of the respondents were aware of the availability of specific prescription drug therapies or surgical options for the treatment of 'BPH'. The most common first treatment strategy for those consulting for symptoms was watchful waiting (34%), followed by surgery (30%) and prescription drugs (21%).

CONCLUSIONS

Moderate-to-severe LUTS were relatively common in this UK population of men over the age of 50, yet relatively few had been diagnosed with 'BPH'. As LUTS adversely affect quality of life, improved treatment options and increased public awareness of BPH and LUTS are needed to combat a problem facing the growing number of elderly men in the population.

A short term cost-effectiveness model for oral antidiabetic medicines in Europe

A short term (6-month) cost-effectiveness model has been developed to simulate current medical practice and disease progression in patients with type 2 (non-insulin-dependent) diabetes mellitus uncontrolled by diet and exercise. The model is based on decision-analytical techniques and includes probabilities of switching between treatments, the reason for the switch and the most common switch options. Effectiveness and economic measures are the 2 main outcomes. In order to assess effectiveness, we use symptom-free days with acceptable control (SFDACs), which represent each day of treatment without adverse events or symptoms, and with acceptable control of glucose and lipids. For the economic evaluation, only incremental costs incurred directly by a health insurance system are considered. This model should prove useful in the evaluation of new oral antidiabetic agents, since the short term aim of antidiabetic therapy is to provide adequate control in the absence of adverse effects and symptoms (a prerequisite for successful long term treatment). Furthermore, short term analysis provides data for comparing initial investment in drug therapy with potential savings over a longer treatment period.

Management of intermittent claudication with pentoxifylline: meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy of pentoxifylline therapy in improving the walking capacity of patients with moderate intermittent claudication.

DATA SOURCES

A search of MEDLINE for trials published between 1976 and 1994 inclusive, and a bibliographic review of all articles retrieved.

STUDY SELECTION

Randomized, placebo-controlled, double-blind clinical trials were selected that evaluated the pain-free walking distance (the distanced walked on a treadmill before the onset of calf pain) and the absolute claudication distance (the maximum distance walked on a treadmill) among patients with moderate intermittent claudication. Twelve study groups in 11 trials were included in the analysis.

DATA EXTRACTION

In addition to information regarding the trial design, patient characteristics, dosages and treatment periods, the means and standard deviations were collected for both the pain-free walking and absolute claudication distances. Trial quality was also assessed.

DATA SYNTHESIS

Overall, there was a statistically significant improvement in the pain-free walking distance after pentoxifylline therapy (weighted mean difference 29.4 m [95% confidence interval (CI) 13.0 to 45.9 m]); this finding was based on a total sample of 612 patients (308 in the treatment groups and 304 in the control groups). A significant improvement was also noted in the absolute claudication distance (weighted mean difference 48.4 m [95% CI 18.3 to 78.6 m]); this was based on a total sample of 511 patients (258 in the treatment group and 253 in the control group). In a sensitivity analysis of the pain-free walking distance, significant treatment effects and no statistically significant heterogeneity were found when only trials were included that were "medically eligible" (involved patients with stage II disease and a pain-free walking distance of 50 to 200 m). In a similar sensitivity analysis of the absolute claudication distance, the two conditions resulting in a significant treatment effect and no significant heterogeneity were the inclusion of "medically eligible" trials and those with a shorter treatment duration (13 weeks or less).

CONCLUSION

Pentoxifylline therapy may be efficacious in improving the walking capacity of patients with moderate intermittent claudication. However, properly conducted clinical trials are required to provide a true estimate of the benefit.