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Dive into the research topics where Leo Turner is active.

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Featured researches published by Leo Turner.


Journal of the American College of Cardiology | 1998

Vascular Reactivity Is Impaired in Genetic Females Taking High-Dose Androgens

Robyn J. McCredie; Jane McCrohon; Leo Turner; Kaye A. Griffiths; David J. Handelsman; David S. Celermajer

OBJECTIVE To assess the vascular effects of high-dose androgen treatment in genetic females. BACKGROUND Male gender is an independent risk factor for coronary artery disease, suggesting either a protective effect of estrogens and/or a deleterious effect of androgens. We have recently demonstrated that androgen deprivation is associated with enhanced vascular reactivity in adult men, however, the effects of androgen excess on vascular function in humans has not been reported previously. METHODS We studied vascular reactivity in two groups of genetic females: 12 female-to-male transsexuals receiving long-term high-dose androgens, and 12 healthy female control subjects, matched for age and smoking history. Using external vascular ultrasound, brachial artery diameter was measured at rest, after flow increase (leading to flow-mediated dilatation [FMD], which depends on normal endothelial function) and after sublingual nitroglycerin (NTG), an endothelium-independent dilator. RESULTS Testosterone levels were higher (15.2+/-8.7 vs. 1.9+/-1.3 mmol/L, p < 0.001) and high-density lipoprotein cholesterol levels were lower (1.2+/-0.2 vs. 1.6+/-0.4 mmol/L, p=0.02) in the transsexuals compared with the control subjects. In each group, nine of 12 subjects were current or ex-smokers, leading to impaired FMD in both groups (5.1+/-3.7% in the transsexuals vs. 6.9+/-4.1% in controls, p=0.28). The NTG response was significantly decreased in the transsexuals (15.9+/-4.9% vs. 22+/-5.8% in controls, p=0.01), independent of the effects of age, cholesterol or vessel size. CONCLUSIONS Long-term treatment with high-dose androgens is associated with impaired vascular reactivity in genetic females, consistent with a deleterious effect of androgen excess on arterial physiology.


Clinical Endocrinology | 2012

Serum testosterone, dihydrotestosterone and estradiol concentrations in older men self-reporting very good health: the healthy man study

Gideon Sartorius; Sasa Spasevska; Amanda Idan; Leo Turner; Elise A Forbes; Anna Zamojska; Carolyn A. Allan; Lam P. Ly; Ann J. Conway; Robert I. McLachlan; David J. Handelsman

To determine serum concentrations, intra‐individual variability and impact of age‐related co‐morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E2) and estrone (E1) in older men.


Journal of the American College of Cardiology | 1997

Arterial Reactivity Is Enhanced in Genetic Males Taking High Dose Estrogens

Jane McCrohon; William A.W Walters; Jacqui Robinson; Robyn J. McCredie; Leo Turner; David J Handelsman; David S. Celermajer

OBJECTIVES We sought to assess whether high dose estrogen treatment is associated with enhanced arterial reactivity in genetic males. BACKGROUND Although estrogens have been shown to enhance arterial reactivity in women, and are thereby thought to confer cardiovascular benefit, the vascular effects of long-term estrogen therapy in genetic males is unknown. METHODS We studied the arterial physiology of 30 genetic males--15 male to female transsexuals receiving long-term high dose estrogen therapy and 15 healthy male control subjects matched for age, smoking history and vessel size. Using external vascular ultrasound, brachial artery diameter was measured at rest, after flow increase (causing endothelium-dependent dilation [EDD]) and after nitroglycerin (GTN), an endothelium-independent dilator. Blood pressure, cholesterol and testosterone levels were also measured in each subject. RESULTS Total testosterone and free testosterone index levels were lower in the transsexuals compared with the control subjects (p < 0.001). In contrast, EDD was significantly higher in the transsexuals than in the control males (mean [+/-SD] 7.1 +/- 3.1% vs. 3.2 +/- 2.8%, p = 0.001), as was the GTN response (21.2 +/- 6.7% vs. 14.6 +/- 3.3%, p = 0.002). Total and high density lipoprotein cholesterol, blood pressure levels and baseline vessel size were similar in the two groups. On multivariate analysis, enhanced EDD was associated independently with estrogen therapy (p = 0.02) and with low total cholesterol (p = 0.04). An enhanced GTN response was also significantly associated with estrogen therapy (p = 0.03). CONCLUSIONS Long-term treatment with high dose estrogens is associated with enhanced arterial reactivity in genetic males, which may be due to the effects of estrogen excess or androgen deprivation, or both.


Clinical Endocrinology | 1997

An analysis of testosterone implants for androgen replacement therapy

David J. Handelsman; Mary-Anne Mackey; Chris J. Howe; Leo Turner; Ann J. Conway

To review 13 years of experience using fused crystalline testosterone implants for androgen replacement therapy in order to identify pattern of usage (including continuation rates) and adverse events emerging during therapy and factors associated with adverse events including implant extrusions.


Annals of Internal Medicine | 2010

Long-Term Effects of Dihydrotestosterone Treatment on Prostate Growth in Healthy, Middle-Aged Men Without Prostate Disease: A Randomized, Placebo-Controlled Trial

Amanda Idan; Kaye A. Griffiths; D. Tim Harwood; Markus J. Seibel; Leo Turner; Ann J. Conway; David J. Handelsman

BACKGROUND Benign prostatic hypertrophy increases with age and can result in substantially decreased quality of life for older men. Surgery is often required to control symptoms. It has been hypothesized that long-term administration of a nonamplifiable pure androgen might decrease prostate growth, thereby decreasing or delaying the need for surgical intervention. OBJECTIVE To test the hypothesis that dihydrotestosterone (DHT), a nonamplifiable and nonaromatizable pure androgen, reduces late-life prostate growth in middle-aged men. DESIGN Randomized, placebo-controlled, parallel-group trial. (Australian New Zealand Clinical Trials Registry number: ACTRN12605000358640) SETTING: Ambulatory care research center. PARTICIPANTS Healthy men (n = 114) older than 50 years without known prostate disease. INTERVENTION Transdermal DHT (70 mg) or placebo gel daily for 2 years. MEASUREMENTS Prostate volume was measured by ultrasonography; bone mineral density (BMD) and body composition were measured by dual-energy x-ray absorptiometry; and blood samples and questionnaires were collected every 6 months, with data analyzed by mixed-model analysis for repeated measures. RESULTS Over 24 months, there was an increase in total (29% [95% CI, 23% to 34%]) and central (75% [CI, 64% to 86%]; P < 0.01) prostate volume and serum prostate-specific antigen level (15% [CI, 6% to 24%]) with time on study, but DHT had no effect (P > 0.2). Dihydrotestosterone treatment decreased spinal BMD (1.4% [CI, 0.6% to 2.3%]; P < 0.001) at 24 months but not hip BMD (P > 0.2) and increased serum aminoterminal propeptide of type I procollagen in the second year of the study compared with placebo. Dihydrotestosterone increased serum DHT levels and its metabolites (5α-androstane-3α,17β-diol and 5α-androstane-3β,17β-diol) and suppressed serum testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormone levels. Dihydrotestosterone increased hemoglobin levels (7% [CI, 5% to 9%]), serum creatinine levels (9% [CI, 5% to 11%]), and lean mass (2.4% [CI, 1.6% to 3.1%) but decreased fat mass (5.2% [CI, 2.6% to 7.7%]) (P <0.001 for all). Protocol-specific discontinuations due to DHT were asymptomatic increased hematocrit (n = 8), which resolved after stopping treatment, and increased prostate-specific antigen levels (n = 3; none with prostate cancer) in the DHT group. No serious adverse effects due to DHT occurred. LIMITATION Negative findings on prostate growth cannot exclude adverse effects on the natural history of prostate cancer. CONCLUSION Dihydrotestosterone treatment for 24 months has no beneficial or adverse effect on prostate growth but causes a decrease in spinal but not hip BMD. These findings have important implications for the wider use of nonsteroidal pure androgens in older men. PRIMARY FUNDING SOURCE BHR Pharma.


Clinical Endocrinology | 1999

Extrusion of testosterone pellets: a randomized controlled clinical study

S. Kelleher; Leo Turner; Howe C; Ann J. Conway; David J. Handelsman

It has previously been shown that testosterone implantation is an effective and well accepted form of androgen replacement therapy, but that pellet extrusion was the most frequent side‐effect. The present study aimed to reduce the extrusion rate.


Clinical Endocrinology | 2009

Randomized cross-over clinical trial of injectable vs. implantable depot testosterone for maintenance of testosterone replacement therapy in androgen deficient men.

Carolyn Fennell; Gideon Sartorius; Lam P. Ly; Leo Turner; Peter Y. Liu; Ann J. Conway; David J. Handelsman

Background  Life‐long testosterone replacement therapy (TRT) for younger men with organic androgen deficiency is best provided by depot testosterone (T) products. This study compared directly the two long‐acting depot T products, subdermal T implants (TI) and injectable T undecanoate (TU) for maintenance of TRT.


Asian Journal of Andrology | 2010

Factors influencing time course of pain after depot oil intramuscular injection of testosterone undecanoate

Gideon Sartorius; Carolyn Fennell; Sasa Spasevska; Leo Turner; Ann J. Conway; David J. Handelsman

Pain following depot intramuscular (IM) injection of oil vehicle-based drugs has been little studied. This study aimed to determine prospectively the prevalence, determinants, severity and functional consequences of pain during the week after IM injection of 1 000 mg testosterone undecanoate (TU) in a 4-mL castor oil vehicle. Androgen-deficient men receiving regular T replacement therapy at an academic andrology clinic were recruited to report pain scores using a coloured visual linear analogue scale at seven times over the first day and daily for a week after a deep IM gluteal injection. The time course and covariables influencing pain scores were analysed by mixed model analysis of variance (ANOVA). Following 168 injections in 125 men, pain was reported by 80% of men, peaking immediately after injection, reaching only moderate severity, lasting 1-2 days and returning to baseline by day 4. The pain required little analgesic use and produced minimal interference in daily activities. The time course of pain scores was reproducible in the 43 men who underwent two consecutive injections. Pain was more severe in men who had an earlier painful injection, but less severe in older and more obese men. There were negligible differences in post-injection pain experience between experienced nurses administering injections. Deep IM gluteal injection of depot TU in 4-mL castor oil is well tolerated and post-injection pain is influenced by earlier painful injection experience, as well as age and obesity.


The Journal of Steroid Biochemistry and Molecular Biology | 2014

Detection and effects on serum and urine steroid and LH of repeated GnRH analog (leuprolide) stimulation.

David J. Handelsman; Amanda Idan; Janelle Grainger; Catrin Goebel; Leo Turner; Ann J. Conway

Non-steroidal drugs that increase endogenous testosterone (T) may be used to exploit ergogenic effects of androgens in power sports. While superactive GnRH analog use is suspected, neither screening nor detection tests are developed. This study aimed to determine if (a) stimulation for 5 days by leuprolide (a superactive GnRH analog) of serum and urine steroids and urine LH is reproducible at a 2 week interval, (b) nandrolone decanoate (ND) co-administration masks responses to leuprolide administration, (c) performance of urine measurement of leuprolide and M1, its major metabolite, as a detection test. Healthy men were randomized into a 4 week parallel group, open label clinical study in which all men had daily sc injections of leuprolide (1mg) for 4 days in the 1st and 3rd weeks with hormone-free 2nd and 4th weeks. In the 3rd week, men were randomized to either ND injections or no extra treatment. Serum steroids were determined by liquid chromatography, tandem mass spectrometry (LC-MS), urine steroids by gas chromatography, mass spectrometry (GC-MS), urine leuprolide and M1 by high resolution LC-MS and urine LH by immunoassay. Leuprolide stimulated striking, reproducible increases in serum and urine LH and steroids (serum T, dihydroT (DHT), 3α diol; urine T, epitestosterone (E) and androsterone (A). ND suppressed basal serum T, E2, 3α diol, and urinary E but did not mask or change the magnitude of responses to leuprolide. Urine leuprolide and M1 measurement had 100% sensitivity and specificity in detecting leuprolide administration up to one day after cessation of injections with the detection window between 1 and 3 days after last dose. Screening using urine steroid and LH measurements, optimally by urinary log10(LHxT), correctly classified 82% of urine samples. It is concluded that leuprolide stimulation of endogenous testosterone is reproducible after a 10-day interval, is not masked by ND and is reliably detected by urine leuprolide or M1 measurement for at least 1 day after administration.


European Journal of Endocrinology | 2015

Complications of injectable testosterone undecanoate in routine clinical practice.

Timothy Middleton; Leo Turner; Carolyn Fennell; Sasha Savkovic; Veena Jayadev; Ann J. Conway; David J. Handelsman

OBJECTIVE Injectable testosterone undecanoate (TU) was marketed within the last decade, but its complications in routine clinical practice are not well defined. DESIGN AND METHODS Prospective observational study of consecutive TU injections in an Andrology Clinic to estimate the incidence of i) immediate cough/syncope due to pulmonary oil microembolisation (POME), ii) post-injection haematoma and iii) the prevalence of secondary polycythaemia. RESULTS In 3022 injections given to 347 patients over 3.5 years, POME was observed after 56 injections (66% mild, 19% severe; 40% with onset before injection completed) in 43 patients. The incidence of 19 (95% CI 14-24) per 1000 injections did not differ between three experienced nurse injectors, but recurrences were more frequent than by chance. No post-injection haematoma was reported including after 269 injections to men taking antiplatelet, anticoagulant or both drugs (upper 95% confidence limit 1%) with 56 not withholding drugs prior to TU administration (upper 95% confidence limit 5.4%). Mean haematocrit was 0.44±0.04 (s.d.) with 25 (7%) >0.50, 14 (4%) >0.52 and 3 (1%) >0.54. CONCLUSION TU injections produce a low incidence of POME with injections by experienced nurses, but recurrence is more frequent than by chance. Post-injection haematoma was not observed even among men using anticoagulant and/or antiplatelet drugs, and polycythaemia was a minor problem rarely requiring treatment other than optimising inter-injection interval.

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Peter Y. Liu

Los Angeles Biomedical Research Institute

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B. Jin

University of Sydney

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Robert I. McLachlan

Hudson Institute of Medical Research

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