PubMed Health⌕ Search

Biomedical subjects

Bronwyn G A Stuckey

Publications and source records attributed to Bronwyn G A Stuckey.

17 recordsLinked to original sources
PubMed2026

Genomic analyses implicate hormonal and metabolic dysregulation in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) and its underlying features remain poorly understood. In this genetic study (n = 544,513), we expand the number of genetic loci from 16 to 29, and additionally identify 31 associated plasma proteins. Many risk-increasing loci were associated with later age at menopause, underscoring the reproductive longevity related to an increased oocyte number and/or availability across the lifespan. Hormonal regulation in the etiology of this condition, through metabolic and reproductive features, was emphasized. The proteomic analysis highlighted metabolic biology known to be related to PCOS. A polygenic risk score (PRS) was associated with adverse cardiometabolic outcomes, with differing relevance of testosterone and body mass index in women and men. Finally, while oligo-anovulation and anovulatory infertility are features of PCOS, we observed no impact of PCOS susceptibility on childlessness. We suggest that PCOS susceptibility confers balanced pleiotropic influences on fertility in women, and life-long adverse metabolic consequences in both sexes.

Humans↗
PubMed2006

Erectile dysfunction predicts generalised cardiovascular disease: evidence from a case-control study.

AIMS: To determine whether idiopathic erectile dysfunction, in the absence of overt cardiovascular disease or cardiovascular risk factors, is associated with vascular or autonomic dysfunction. METHODS: We studied 49 men with ED (without known cardiovascular risk factors or disease) and 50 age-matched controls, aged 40-70 years. Macrovascular endothelial function was examined by brachial artery ultrasonography and microvascular function by venous occlusion plethysmography. Blood pressure measurement and electrocardiography were performed lying and standing, and the 30:15 RR ratio calculated. RESULTS: Body mass index, testosterone, fasting lipids and glucose did not differ significantly between groups. Standing pulse pressure was higher (50+/-1mm Hg versus 43+/-2mm Hg, p<0.004) and 30:15 RR ratio lower (0.97+/-0.01 versus 1.01+/-0.01, p<0.02) in the ED group. Flow-mediated dilatation of the brachial artery was not significantly different between groups. Flow debt repayment during forearm reactive hyperaemia was lower in the ED group (7.2+/-0.7 ml versus 9.5+/-0.8 ml per 100ml, p<0.02) than in controls. CONCLUSIONS: Men with idiopathic ED have evidence of endothelial dysfunction in forearm resistance vessels, increased pulse pressure and impaired heart rate variability. This supports the concept that erectile dysfunction is a predictor of cardiovascular dysfunction and a precursor of clinical cardiovascular disease.

Adult↗
PubMed2006

Small changes in thyroxine dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life: results of a double-blind, randomized clinical trial.

CONTEXT: In patients with primary hypothyroidism, anecdotal evidence suggests that well-being is optimized by fine adjustment of T(4) dosage, aiming for a serum TSH concentration in the lower reference range. This has not been tested in a clinical trial. OBJECTIVE: Our objective was to test whether adjustment of T(4) dosage aiming for a serum TSH concentration less than 2 mU/liter improves well-being compared with a serum TSH concentration in the upper reference range. DESIGN: We conducted a double-blind, randomized clinical trial with a crossover design. PARTICIPANTS: Fifty-six subjects (52 females) with primary hypothyroidism taking T(4) (>/=100 microg/d) with baseline serum TSH 0.1-4.8 mU/liter participated. INTERVENTIONS: Each subject received three T(4) doses (low, middle, and high in 25-microg increments) in random order. OUTCOME MEASURES: Outcome measures included visual analog scales assessing well-being (the primary endpoint) and hypothyroid symptoms, quality of life instruments (General Health Questionnaire 28, Short Form 36, and Thyroid Symptom Questionnaire), cognitive function tests, and treatment preference. RESULTS: Mean (+/- sem) serum TSH concentrations were 2.8 +/- 0.4, 1.0 +/- 0.2, and 0.3 +/- 0.1 mU/liter for the three treatments. There were no significant treatment effects on any of the instruments assessing well-being, symptoms, quality of life, or cognitive function and no significant treatment preference. CONCLUSIONS: Small changes in T(4) dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life, despite the expected changes in serum TSH and markers of thyroid hormone action. These data do not support the suggestion that the target TSH range for the treatment of primary hypothyroidism should differ from the general laboratory range.

Adult↗
PubMed2006

Polymorphism in HSD17B6 is associated with key features of polycystic ovary syndrome.

OBJECTIVE: To investigate polymorphisms in androgen metabolism regulators that are implicated in the etiology of polycystic ovary syndrome (PCOS) in vitro; to investigate HSD17B6 and GATA6 to determine whether these genes are associated with susceptibility to PCOS or key phenotypic features of patients with PCOS. DESIGN: Case-control association study. SETTING: Participants with PCOS were recruited from a clinical-practice database, and controls, from the general community. PATIENT(S): One hundred seventy-three patients with PCOS and who were of Caucasian descent and conformed to the National Institutes of Health (NIH) diagnostic criteria; 107 normally ovulating women of Caucasian descent from the general community. INTERVENTION(S): Drawing of blood for DNA extraction. MAIN OUTCOME MEASURE(S): Frequency of HSD17B6 and GATA6 polymorphisms in cases and controls. Association of single-nucleotide polymorphisms from HSD17B6 in subjects with PCOS with key phenotypes of PCOS: androgen status, insulin resistance, and body mass index. RESULT(S): Allele distribution for the single-nucleotide polymorphism rs898611 in HSD17B6 was significantly different between PCOS and control subjects (P=.03). Presence of the polymorphic allele was associated with reduced fasting glucose-insulin ratio (P=.02) and increased homeostasis model assessment (P<.01) and body mass index (P<.001) as well as with reduced T (P=.03) in the PCOS group. No association was seen between GATA6 and any of the variables studied. CONCLUSION(S): These data suggest that polymorphisms in the HSD17B6 gene are associated with PCOS and key clinical phenotypes of the disorder.

Adult↗
PubMed2006

Novel mutations in the calcium-sensing receptor gene associated with biochemical and functional differences in familial hypocalciuric hypercalcaemia.

OBJECTIVE: Heterozygous inactivating mutations of the calcium-sensing receptor (CaR) gene cause familial hypocalciuric hypercalcaemia (FHH), a generally benign disorder characterized by mild to moderate PTH-dependent hypercalcaemia. We aimed to identify the causative CaR mutations in three families with FHH and examine the correlation between type of mutation and biochemical and/or functional phenotypes. PATIENTS, DESIGN AND MEASUREMENTS: The CaR gene from FHH family members was assessed for mutations by direct DNA sequencing and mutations were confirmed by restriction enzyme analysis. Functional studies on two missense mutations were conducted by introducing them by site-directed mutagenesis into the CaR cloned into a mammalian expression vector, and assessing calcium responsiveness using an inositol phosphate (IP) assay in HEK293 cells. Biochemical data from patients heterozygous for each type of mutant were correlated with functionality. RESULTS: Two novel nonsense mutations (R25stop and K323stop) and one novel missense mutation (G778D) were identified. The G778D mutant receptor and another mutation identified in an earlier study (L174R) demonstrated a complete lack of Ca2+ responsiveness using the IP assay. When cotransfected with wild-type receptor, the mutant receptors demonstrated a dominant-negative effect on wild-type receptor response, with L174R having a more pronounced effect than G778D. Significantly more severe hypercalcaemia and a trend towards higher PTH levels were observed in patients heterozygous for CaR mutants with a stronger dominant-negative effect. CONCLUSIONS: Naturally occurring CaR mutations with differences in dominant-negative effect on wild-type receptor demonstrate differences in biochemical severity in FHH.

Animals↗
PubMed2006

A novel homozygous deletion in the calcium-sensing receptor ligand-binding domain associated with neonatal severe hyperparathyroidism.

Neonatal severe hyperparathyroidism (NSHPT) is a life-threatening disorder usually caused by homozygous mutations occurring in the calcium-sensing receptor (CaR) gene. We examined an infant hospitalised with NSHPT for mutations in the CaR gene using heterozygous sequence analysis and confirmed this result by a restriction enzyme assay. Clinical management of this case, which was beset by other complications, involved control of the hypercalcemia and the effects of hyperparathyroidism by a combination of treatments prior to parathyroidectomy performed at 10 months. Mutational analysis demonstrated a homozygous 5 base-pair deletion in the CaR gene located at the 5' end of exon 4 which would result in a severely truncated, non-functional receptor with only the first 164 amino acids of the CaR followed by 23 amino acids of aberrant sequence. This is the first report of an out-of-frame deletion in the extracellular domain of the CaR associated with clinical disease.

Frameshift Mutation↗
PubMed2005

Cardiovascular disease in the polycystic ovary syndrome: new insights and perspectives.

The new millennium has brought intense focus of interest on the risk of cardiovascular disease in women. The polycystic ovary syndrome (PCOS) is a common endocrine disorder in women characterised by hyperandrogenism and oligomenorrhoea. Most women with PCOS also exhibit features of the metabolic syndrome, including insulin resistance, obesity and dyslipidaemia. While the association with type 2 diabetes is well established, whether the incidence of cardiovascular disease is increased in women with PCOS remains unclear. Echocardiography, imaging of coronary and carotid arteries, and assessments of both endothelial function and arterial stiffness have recently been employed to address this question. These studies have collectively demonstrated both structural and functional abnormalities of the cardiovascular system in PCOS. These alterations, however, appear to be related to the presence of individual cardiovascular risk factors, particularly insulin resistance, rather than to the presence of PCOS and hyperandrogenaemia per se. However, given the inferential nature of the evidence to date, more rigorous cohort studies of long-term cardiovascular outcomes and clinical trials of risk factor modification are required in women with PCOS.

Arteries↗
PubMed2005

Management of menopausal symptoms in patients with breast cancer: an evidence-based approach.

Increasing numbers of women have menopausal symptoms after treatment for breast cancer. These symptoms can result directly from cancer treatments (such as oophorectomy, ovarian suppression, chemotherapy-induced ovarian failure, and antioestrogens), as a spontaneous event, or after discontinuation of hormone-replacement therapy. The onset of menopausal symptoms after treatment for breast cancer can have a long-lasting effect on quality of life, body image, sexual function, and self esteem. Hormone-replacement therapy that contains oestrogen is the most effective treatment for menopausal symptoms in healthy women. However, evidence from one randomised controlled trial suggests that use of hormone replacement therapy after breast cancer raises the risk of recurrence and of new primary breast cancer. As the incidence of breast cancer increases and survival continues to improve, the number of women with menopausal symptoms will probably rise. Safe and effective non-hormonal treatments for severe menopausal symptoms after breast cancer are urgently needed. Few studies have addressed the management of menopausal symptoms after breast cancer, and the quality of studies is generally poor. Progestagens, and selective inhibitors of serotonin and norepinephrine reuptake seem to offer reasonable symptom palliation, but the long-term effectiveness and safety of these preparations is not known. We propose that the management of menopausal symptoms in patients with a history of cancer requires a patient-centred, but multidisciplinary, approach.

Breast Neoplasms↗
PubMed2005

Polycystic ovarian syndrome: marked differences between endocrinologists and gynaecologists in diagnosis and management.

BACKGROUND: Women with polycystic ovarian syndrome (PCOS) commonly consult endocrinologists or gynaecologists and it is not known whether these specialty groups differ in their approach to management. OBJECTIVE: To compare the investigation, diagnosis and treatment practices of endocrinologists and gynaecologists who treat PCOS. DESIGN AND SETTING: A mailed questionnaire containing a hypothetical patient's case history with varying presentations--oligomenorrhoea, hirsutism, infertility and obesity--was sent to Australian clinical endocrinologists and gynaecologists in teaching hospitals and private practice. RESULTS: Evaluable responses were obtained from 138 endocrinologists and 172 gynaecologists. The two specialty groups differed in their choice of essential diagnostic criteria and investigations. Endocrinologists regarded androgenization (81%) and menstrual irregularity (70%) as essential diagnostic criteria, whereas gynaecologists required polycystic ovaries (61%), androgenization (59%), menstrual irregularity (47%) and an elevated LH/FSH ratio (47%) (all P-values < 0.001). In investigation, gynaecologists were more likely to request ovarian ultrasound (91%vs. 44%, P < 0.001) and endocrinologists more likely to measure adrenal androgens (80%vs. 58%, P < 0.001) and lipids (67%vs. 34%, P < 0.001). Gynaecologists were less likely to assess glucose homeostasis but more likely to use a glucose tolerance test to do so. Diet and exercise were chosen by most respondents as first-line treatment for all presentations. However, endocrinologists were more likely to use insulin sensitizers, particularly metformin, for these indications. In particular, for infertility, endocrinologists favoured metformin treatment whereas gynaecologists recommended clomiphene. CONCLUSIONS: There is a lack of consensus between endocrinologists and gynaecologists in the definition, diagnosis and treatment of PCOS. As a consequence, women may receive a different diagnosis or treatment depending on the type of specialist consulted.

Australia↗
PubMed2005

Efficacy of sildenafil citrate (Viagra) in men with premature ejaculation.

OBJECTIVES: Premature ejaculation (PE) is the most common ejaculatory dysfunction. We assessed the efficacy of sildenafil to increase the time to ejaculation, improve ejaculatory control, and decrease the postejaculatory erectile refractory time in men with PE. DESIGN AND METHODS: The main study was an 8-week, double-blind, placebo-controlled, parallel group study in men between 18 and 65 years of age with diagnosed PE. A substudy was also conducted using a subset of patients (two-way crossover, one center) before entry to the main study. The primary study measured intravaginal ejaculatory latency (IELT) and responses to the Index of Premature Ejaculation (IPE) questionnaire. The substudy measured vibrotactile stimulation ejaculatory latency time (VTS-ELT) and postejaculatory erectile refractory time. Differences between treatment groups were determined by ancova at the 5% level of significance. RESULTS: The change in IELT (1.6 +/- 6.08 vs. 0.6 +/- 2.07 minutes) and VTS-ELT (2.9 +/- 0.4 vs. 2.4 +/- 0.4 minutes) were higher after taking sildenafil, compared with placebo, but did not reach statistical significance. However, patients who took sildenafil (vs. placebo) reported significantly (P < 0.05) increased ejaculatory control (1.8 +/- 0.3 vs. 1.5 +/- 0.3), increased ejaculatory confidence (2.2 +/- 0.2 vs. 1.9 +/- 0.2), and improved overall sexual satisfaction scores (3.1 +/- 0.2 vs. 2.8 +/- 02) on the IPE, and had a decreased postejaculatory erectile refractory time (3.2 +/- 0.7 vs. 6.4 +/- 0.7 minutes). The most common adverse events for sildenafil (vs. placebo) were headache (15% vs. 1%), flushing (15% vs. 0%), dyspepsia (5% vs. 1%), abnormal vision (5% vs. 0%), and rhinitis (5% vs. 0%). CONCLUSIONS: Although IELT and VTS-ELT were not significantly improved, sildenafil increased confidence, the perception of ejaculatory control, and overall sexual satisfaction, and decreased the refractory time to achieve a second erection after ejaculation in men with PE.

Adolescent↗
PubMed2004

Functional deletion of the calcium-sensing receptor in a case of neonatal severe hyperparathyroidism.

Heterozygous inactivating mutations of the calcium-sensing receptor (CaR) cause familial hypocalciuric hypercalcemia, whereas homozygous or compound heterozygous inactivating mutations normally cause neonatal severe hyperparathyroidism. In a case of neonatal severe hyperparathyroidism characterized by moderately severe hypercalcemia and very high PTH levels, coupled with evidence of hyperparathyroidism and effects on brain development not previously demonstrated, we detected point mutations on separate alleles of the CaR, resulting in premature stop codon substitutions at G94 and R648. This led to severely truncated receptors and an effective so-called knockout of functional CaR. FLAG-tagged, truncated receptors were expressed in HEK293 cells for functional analysis. Confocal microscopy demonstrated cytoplasmic localization of the G94stop receptor, whereas the R648stop receptor was present both in the cytoplasm and associated with the cell membrane. Only the R648stop receptor could be detected by Western analysis. Functional assays in which R648stop and wild-type receptor were cotransfected into HEK293 cells demonstrated a reduction in wild-type Ca(2+)-responsiveness by the R648stop receptor, even at physiological Ca(2+) levels, thus simulating familial hypocalciuric hypercalcemia in relatives of the infant who were heterozygous for the R648stop mutation. The R648stop receptor alone was nonresponsive to Ca(2+). This case contributes to our understanding of the clinical manifestation of a CaR knockout.

Alleles↗
PubMed2003

Alendronate prevents loss of bone density associated with discontinuation of hormone replacement therapy: a randomized controlled trial.

BACKGROUND: Many women using hormone replacement therapy (HRT) will discontinue HRT and lose its bone-protective effect. Methods to preserve bone density in these women need to be explored. This multicenter, international, randomized, blinded, 12-month study was conducted to assess the effect of alendronate sodium on bone density in women who had recently discontinued HRT. METHODS: The 144 postmenopausal women included in the study were diagnosed as having low bone mineral density (BMD) and had recently discontinued HRT. They were randomized to receive either a daily dose of 10 mg of alendronate sodium or matching placebo. The main outcome measures were spine, hip, and total body BMD; biochemical markers of bone turnover; and tolerability. RESULTS: Alendronate treatment was associated with a 2.3% mean increase (95% confidence interval [CI], 1.7%-3.0%) in spine BMD compared with a mean loss of 3.2% (95% CI, - 4.6% to - 1.7%) in patients receiving placebo, for a difference of 5.5% (95% CI, 4.2%-6.8%) between alendronate and placebo. Greater hip and total body BMD preservation was also observed with alendronate use. Bone turnover decreased significantly with alendronate (bone-specific alkaline phosphatase levels decreased by 20% and urinary N-telopeptide/creatinine ratio by 47%), but increased in the placebo group (by 18% and 36%, respectively). Alendronate was well tolerated, with no increase in adverse events compared with placebo. CONCLUSIONS: A high rate of bone loss was observed in the first 12 to 15 months after discontinuation of HRT in postmenopausal women with low BMD. Treatment with alendronate increased or maintained both spine and hip BMD and prevented the increase in bone resorption seen with withdrawal of HRT in this population.

Alendronate↗
PubMed2003

Biochemical screening in the assessment of erectile dysfunction: what tests decide future therapy?

OBJECTIVES: To evaluate which biochemical tests, performed as screening tests in the assessment of erectile dysfunction (ED), lead to a change in standard treatment. METHODS: We examined the results of the biochemical and endocrine tests performed as part of the assessment of 1455 men presenting with ED. We also documented the subsequent therapy. RESULTS: We found abnormal findings in testosterone (5.7%), prolactin (0.5%), thyroid function tests (0.13%), liver function tests (12.8%), glucose (9.3%), cholesterol (15% in a subset of 531 men), and ferritin (1.6%). Hyperprolactinemia was not invariably associated with a suppressed testosterone level. Specific therapy with a dopamine agonist for hyperprolactinemia and with testosterone for hypogonadism was effective in treating ED. For the others, standard ED therapy was used. CONCLUSIONS: The results of our study showed that screening tests fall into two categories. Testosterone and prolactin have a low yield but specific therapy is effective. Glucose and lipids have a higher yield but specific therapy is not immediately effective for ED. However, they, on their own merits, require management to prevent long-term morbidity and mortality.

Adolescent↗
PubMed2003

Combined thyroxine/liothyronine treatment does not improve well-being, quality of life, or cognitive function compared to thyroxine alone: a randomized controlled trial in patients with primary hypothyroidism.

T(4) is standard treatment for hypothyroidism. A recent study reported that combined T(4)/liothyronine (T(3)) treatment improved well-being and cognitive function compared with T(4) alone. We conducted a double-blind, randomized, controlled trial with a crossover design in 110 patients (101 completers) with primary hypothyroidism in which liothyronine 10 micro g was substituted for 50 micro g of the patients' usual T(4) dose. No significant (P < 0.05) difference between T(4) and combined T(4)/T(3) treatment was demonstrated on cognitive function, quality of life scores, Thyroid Symptom Questionnaire scores, subjective satisfaction with treatment, or eight of 10 visual analog scales assessing symptoms. For the General Health Questionnaire-28 and visual analog scales assessing anxiety and nausea, scores were significantly (P < 0.05) worse for combined treatment than for T(4) alone. Serum TSH was lower during T(4) treatment than during combined T(4)/T(3) treatment (mean +/- SEM, 1.5 +/- 0.2 vs. 3.1 +/- 0.2 mU/liter; P < 0.001), a potentially confounding factor; however, subgroup analysis of subjects with comparable serum TSH concentrations during each treatment showed no benefit from combined treatment compared with T(4) alone. We conclude that in the doses used in this study, combined T(4)/T(3) treatment does not improve well-being, cognitive function, or quality of life compared with T(4) alone.

Adult↗
PubMed2003

Sildenafil citrate for treatment of erectile dysfunction in men with type 1 diabetes: results of a randomized controlled trial.

OBJECTIVE: In the 5-10% of diabetic men with type 1 diabetes, erectile dysfunction (ED) may be a particularly common and unwanted complication. This is the first study focusing exclusively on the effects of sildenafil in men with type 1 diabetes and ED. RESEARCH DESIGN AND METHODS: A total of 188 patients were entered into a double-blind, placebo-controlled, parallel-group, flexible-dose study and were randomized to receive sildenafil (25-100 mg; n = 95) or placebo (n = 93) for 12 weeks. Efficacy was evaluated using questions three (Q3; achieving an erection) and four (Q4; maintaining an erection) from the International Index of Erectile Function (IIEF), a global efficacy question (GEQ; "Did treatment improve your erections?"), and a patient event log of sexual activity. RESULTS: Improvements in mean scores from baseline to end-of-treatment for IIEF Q3 (35.7 vs. 19.9%) and Q4 (68.4 vs. 26.5%) were significant in patients receiving sildenafil compared with those receiving placebo (P = 0.0001). Moreover, the percent of improved erections (GEQ, 66.6 vs. 28.6%) and successful intercourse attempts (63 vs. 33%) was significantly increased with sildenafil compared with placebo. Improvements in sexual function were seen irrespective of the degree of ED severity. Adverse events were generally mild to moderate in severity, with headache (20 vs. 8%), flushing (18 vs. 3%), and dyspepsia (8 vs. 1%) reported more often in the sildenafil than in placebo-treated patients. CONCLUSIONS: Treatment with sildenafil for ED was effective, resulting in an increased percentage of successful attempts at intercourse, and was well tolerated among men with type 1 diabetes.

Adult↗