Skip to main content

Home/ Dr. Goodyear/ Group items tagged author

Rss Feed Group items tagged

Nathan Goodyear

Vitamin D status and ill health: a systematic review : The Lancet Diabetes & Endocrinology - 0 views

  •  
    Another ill conceived conclusion by the authors.  IF you are going to study something, know everything about it.  They authors make a major statement about vitamin D, yet they seem to understand a basic understanding of vitamin dosing.  The authors stated that dosing 2,000 IU of vitamin D in those with levels < 50 provided no benefit.  That is of course correct, because 2,000 IU daily won't hold any levels stable, let alone increase levels to 70-80 where they need to be.  The authors of this study are stuck in the traditional RDC thinking here. What is interesting is that low vitamin D was associated with CVD, MS, dyslipidemia, inflammation, glucose dysmetabolism, infections, mood disorders, decline in cognition, impaired physical functioning, and all-cause mortality,  But, vitamin D supplementation is only good for bones.  The authors of this study make a mockery of medicine.
Nathan Goodyear

Does Testosterone Lower Risk of Heart Attacks and Stroke? | Medical Research News and I... - 0 views

  •  
    This is a short interview of the author on a recent retrospective review that revealed no increase in cardiovascular events in men.  The author rightly points out his data, which is quite different than the previous JAMA and PLOSone publications which showed an increase in cardiovascular events.   However, the lead author points out the main problem with comparisons:  his study group was younger and healthier.  So, the comparison is apples to oranges.  Studies still point to increased risk of Testosterone therapy in men with pre-existing CVD.  This new study does not refute this point at all.   Another serious flaw here, is that only Testosterone was followed.  This logic is seriously flawed as I have previously documented.  The author points out the flaw in the levels in the JAMA study post treatment.  But he fails to account for the the lack of adequate pathway assessment i.e.aromatazation.  Also, no inflammatory cytokine evaluation was performed in that study.  Both of these should have been highlighted.    In contrast, a positive was the length of follow.
Nathan Goodyear

Testosterone levels improve in obese men following a common weight-loss operation: Slee... - 0 views

  •  
    The ignorance of this authors statements is unmeasurable.  Numerous other studies have shown weight loss in men with obesity is associated with increased Testosterone production.  My book highlights the mechanism by which adipose tissue decreased Testosterone production.  The author was quoted as pointed to no Testosterone replacement (even if levels are low????) despite the evidence that Testosterone will improve glucose metabolism, build muscle (reverse sarcopenia obesity), improve cholesterol metabolism,  and significantly aid Diabetes control just to name a few; yet the author says, give surgery instead.  I am sure the author is a surgeon and thus bias might, just might, be present.
Nathan Goodyear

Comparative Studies of the Estrogen Receptors β and α and the Androgen Recept... - 0 views

  • ER-β is predominately immunolocalized in basal cells and to a lesser extent in stromal cells of the morphologically normal human prostate
  • ER-α is detected in stromal cells and rarely in basal cells of the normal gland
  • AR was predominately localized in the nuclei of differentiated secretory cells and variably in basal cells of the normal acinar/duct unit as well as in stromal cells
  • ...9 more annotations...
  • Hall and colleagues44 have reported that ER-β functions as a transdominant inhibitor of ER-α transcription and that it acts to decrease overall cellular sensitivity to estradiol
  • proliferative signals mediated by AR in basal cells or by ER-α and AR in stromal cells may be opposed by the purported growth-inhibitory action of ER-β25, 26, 27, 28 localized in basal cells.
  • The transition from normal to low/moderate dysplastic glands in the peripheral zone was marked by the appearance of ER-β homogeneously immunostained nuclei in secretory as well as basal cells with no changes in the localization of the other receptors.
  • The expression of ER-β was diminished in high-grade dysplasias when compared to normal glands and lower grade lesions.
  • The diminution of ER-β expression in high-grade dysplasias and grade 4/5 cancers may be therefore related to the alteration of DNA methylation pattern in CpG islands of the promoter, resulting in down-regulation of the receptor at the transcriptional level
  • based on the proposed anti-proliferative function of the receptor,25, 26, 27, 28 the presence of ER-β in secretory cells of low/moderate-grade lesions may represent a transient abortive attempt to counter growth of these cells
  • the attrition of receptor-positive basal cells in the high-grade dysplasias may signify a continuing loss of growth inhibitory function mediated by ER-β in these precursor lesions
  • Our findings in prostate therefore differ from those reported for human colon cancer in which Folley and colleagues48 demonstrated that a selective loss of ER-β protein but not receptor message expression occurs in these neoplasms
  • Our findings therefore differed from those of Bonkhoff and colleagues33 who found immunostaining for the receptor in high-grade dysplasias and grade 4/5 carcinomas. Using in situ hybridization these authors also reported that a high percentage of dysplasias and carcinomas in their study contained cells that expressed ER-α message
  •  
    Very nice study.  The authors looked at normal prostate, early disease and late stage prostate cancer.  The authors found that ER beta expression, as a general rule, was lost as progression occurred to the high-grade dysplasias and grad 4/5 carcinomas of the prostate.  Early low/moderate dysplasia was associated with an increase in ER beta--the authors propose that this was due to an attempt of the basal epithelium to counter the paracrine effect of ER alpha.   In contrast, androgen receptors appeared to be equally expressed across all.
Nathan Goodyear

Aromatase and regulation of the estrogen-to... [Ann N Y Acad Sci. 2014] - PubMed - NCBI - 0 views

  •  
    Study looked at inflammatory markers in RA.  The authors point to high aromatase activity, low androgens, and elevated estrone in synovial fluid as an indicator of a link between aromatase activity and inflammation production through E1 production.  The authors also point to the 16 alpha metabolite pathway as pro-inflammatory as well.  One very interesting point made by the authors is that vitamin D down regulates aromatase activity.  In addition to NK-kappaB inhibition, this may be another mechanism by which vitamin D reduces inflammation.
Nathan Goodyear

Testosterone and the Cardiovascular System: A Comprehensive Review of the Clinical Lite... - 0 views

  • Low endogenous bioavailable testosterone levels have been shown to be associated with higher rates of all‐cause and cardiovascular‐related mortality.39,41,46–47 Patients suffering from CAD,13–18 CHF,137 T2DM,25–26 and obesity27–28
  • have all been shown to have lower levels of endogenous testosterone compared with those in healthy controls. In addition, the severity of CAD15,17,29–30 and CHF137 correlates with the degree of testosterone deficiency
  • In patients with CHF, testosterone replacement therapy has been shown to significantly improve exercise tolerance while having no effect on LVEF
  • ...66 more annotations...
  • testosterone therapy causes a shift in the skeletal muscle of CHF patients toward a higher concentration of type I muscle fibers
  • Testosterone replacement therapy has also been shown to improve the homeostatic model of insulin resistance and hemoglobin A1c in diabetics26,68–69 and to lower the BMI in obese patients.
  • Lower levels of endogenous testosterone have been associated with longer duration of the QTc interval
  • testosterone replacement has been shown to shorten the QTc interval
  • negative correlation has been demonstrated between endogenous testosterone levels and IMT of the carotid arteries, abdominal aorta, and thoracic aorta
  • These findings suggest that men with lower levels of endogenous testosterone may be at a higher risk of developing atherosclerosis.
  • Current guidelines from the Endocrine Society make no recommendations on whether patients with heart disease should be screened for hypogonadism and do not recommend supplementing patients with heart disease to improve survival.
  • The Massachusetts Male Aging Study also projects ≈481 000 new cases of hypogonadism annually in US men within the same age group
  • since 1993 prescriptions for testosterone, regardless of the formulation, have increased nearly 500%
  • Testosterone levels are lower in patients with chronic illnesses such as end‐stage renal disease, human immunodeficiency virus, chronic obstructive pulmonary disease, type 2 diabetes mellitus (T2DM), obesity, and several genetic conditions such as Klinefelter syndrome
  • A growing body of evidence suggests that men with lower levels of endogenous testosterone are more prone to develop CAD during their lifetimes
  • There are 2 major potential confounding factors that the older studies generally failed to account for. These factors are the subfraction of testosterone used to perform the analysis and the method used to account for subclinical CAD.
  • The biologically inactive form of testosterone is tightly bound to SHBG and is therefore unable to bind to androgen receptors
  • The biologically inactive fraction of testosterone comprises nearly 68% of the total testosterone in human serum
  • The biologically active subfraction of testosterone, also referred to as bioavailable testosterone, is either loosely bound to albumin or circulates freely in the blood, the latter referred to as free testosterone
  • It is estimated that ≈30% of total serum testosterone is bound to albumin, whereas the remaining 1% to 3% circulates as free testosterone
  • it can be argued that using the biologically active form of testosterone to evaluate the association with CAD will produce the most reliable results
  • English et al14 found statistically significant lower levels of bioavailable testosterone, free testosterone, and free androgen index in patients with catheterization‐proven CAD compared with controls with normal coronary arteries
  • patients with catheterization‐proven CAD had statistically significant lower levels of bioavailable testosterone
  • In conclusion, existing evidence suggests that men with CAD have lower levels of endogenous testosterone,13–18 and more specifically lower levels of bioavailable testosterone
  • low testosterone levels are associated with risk factors for CAD such as T2DM25–26 and obesity
  • In a meta‐analysis of these 7 population‐based studies, Araujo et al41 showed a trend toward increased cardiovascular mortality associated with lower levels of total testosterone, but statistical significance was not achieved (RR, 1.25
  • the authors showed that a decrease of 2.1 standard deviations in levels of total testosterone was associated with a 25% increase in the risk of cardiovascular mortality
  • the relative risk of all‐cause mortality in men with lower levels of total testosterone was calculated to be 1.35
  • higher risk of cardiovascular mortality is associated with lower levels of bioavailable testosterone
  • Existing evidence seems to suggest that lower levels of endogenous testosterone are associated with higher rates of all‐cause mortality and cardiovascular mortality
  • studies have shown that lower levels of endogenous bioavailable testosterone are associated with higher rates of all‐cause and cardiovascular mortality
  • It may be possible that using bioavailable testosterone to perform mortality analysis will yield more accurate results because it prevents the biologically inactive subfraction of testosterone from playing a potential confounding role in the analysis
  • The earliest published material on this matter dates to the late 1930s
  • the concept that testosterone replacement therapy improves angina has yet to be proven wrong
  • In more recent studies, 3 randomized, placebo‐controlled trials demonstrated that administration of testosterone improves myocardial ischemia in men with CAD
  • The improvement in myocardial ischemia was shown to occur in response to both acute and chronic testosterone therapy and seemed to be independent of whether an intravenous or transdermal formulation of testosterone was used.
  • testosterone had no effect on endothelial nitric oxide activity
  • There is growing evidence from in vivo animal models and in vitro models that testosterone induces coronary vasodilation by modulating the activity of ion channels, such as potassium and calcium channels, on the surface of vascular smooth muscle cells
  • Experimental studies suggest that the most likely mechanism of action for testosterone on vascular smooth muscle cells is via modulation of action of non‐ATP‐sensitive potassium ion channels, calcium‐activated potassium ion channels, voltage‐sensitive potassium ion channels, and finally L‐type calcium ion channels
  • Corona et al confirmed those results by demonstrating that not only total testosterone levels are lower among diabetics, but also the levels of free testosterone and SHBG are lower in diabetic patients
  • Laaksonen et al65 followed 702 Finnish men for 11 years and demonstrated that men in the lowest quartile of total testosterone, free testosterone, and SHBG were more likely to develop T2DM and metabolic syndrome.
  • Vikan et al followed 1454 Swedish men for 11 years and discovered that men in the highest quartile of total testosterone were significantly less likely to develop T2DM
  • authors demonstrated a statistically significant increase in the incidence of T2DM in subjects receiving gonadotropin‐releasing hormone antagonist therapy. In addition, a significant increase in the rate of myocardial infarction, stroke, sudden cardiac death, and development of cardiovascular disease was noted in patients receiving antiandrogen therapy.67
  • Several authors have demonstrated that the administration of testosterone in diabetic men improves the homeostatic model of insulin resistance, hemoglobin A1c, and fasting plasma glucose
  • Existing evidence strongly suggests that the levels of total and free testosterone are lower among diabetic patients compared with those in nondiabetics
  • insulin seems to be acting as a stimulant for the hypothalamus to secret gonadotropin‐releasing hormone, which consequently results in increased testosterone production. It can be argued that decreased stimulation of the hypothalamus in diabetics secondary to insulin deficiency could result in hypogonadotropic hypogonadism
  • BMI has been shown to be inversely associated with testosterone levels
  • This interaction may be a result of the promotion of lipolysis in abdominal adipose tissue by testosterone, which may in turn cause reduced abdominal adiposity. On the other hand, given that adipose tissue has a higher concentration of the enzyme aromatase, it could be that increased adipose tissue results in more testosterone being converted to estrogen, thereby causing hypogonadism. Third, increased abdominal obesity may cause reduced testosterone secretion by negatively affecting the hypothalamus‐pituitary‐testicular axis. Finally, testosterone may be the key factor in activating the enzyme 11‐hydroxysteroid dehydrogenase in adipose tissue, which transforms glucocorticoids into their inactive form.
  • increasing age may alter the association between testosterone and CRP. Another possible explanation for the association between testosterone level and CRP is central obesity and waist circumference
  • Bai et al have provided convincing evidence that testosterone might be able to shorten the QTc interval by augmenting the activity of slowly activating delayed rectifier potassium channels while simultaneously slowing the activity of L‐type calcium channels
  • consistent evidence that supplemental testosterone shortens the QTc interval.
  • Intima‐media thickness (IMT) of the carotid artery is considered a marker for preclinical atherosclerosis
  • Studies have shown that levels of endogenous testosterone are inversely associated with IMT of the carotid artery,126–128,32,129–130 as well as both the thoracic134 and the abdominal aorta
  • 1 study has demonstrated that lower levels of free testosterone are associated with accelerated progression of carotid artery IMT
  • another study has reported that decreased levels of total and bioavailable testosterone are associated with progression of atherosclerosis in the abdominal aorta
  • These findings suggest that normal physiologic testosterone levels may help to protect men from the development of atherosclerosis
  • Czesla et al successfully demonstrated that the muscle specimens that were exposed to metenolone had a significant shift in their composition toward type I muscle fibers
  • Type I muscle fibers, also known as slow‐twitch or oxidative fibers, are associated with enhanced strength and physical capability
  • It has been shown that those with advanced CHF have a higher percentage of type II muscle fibers, based on muscle biopsy
  • Studies have shown that men with CHF suffer from reduced levels of total and free testosterone.137 It has also been shown that reduced testosterone levels in men with CHF portends a poor prognosis and is associated with increased CHF mortality.138 Reduced testosterone has also been shown to correlate negatively with exercise capacity in CHF patients.
  • Testosterone replacement therapy has been shown to significantly improve exercise capacity, without affecting LVEF
  • the results of the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not cause an increase in the rate of adverse cardiovascular events
  • Data from 3 meta‐analyses seem to contradict the commonly held belief that testosterone administration may increase the risk of developing prostate cancer
  • One meta‐analysis reported an increase in all prostate‐related adverse events with testosterone administration.146 However, when each prostate‐related event, including prostate cancer and a rise in PSA, was analyzed separately, no differences were observed between the testosterone group and the placebo group
  • the existing data from the 3 meta‐analyses seem to indicate that testosterone replacement therapy does not increase the risk of adverse cardiovascular events
  • the authors correctly point out the weaknesses of their study which include retrospective study design and lack of randomization, small sample size at extremes of follow‐up, lack of outcome validation by chart review and poor generalizability of the results given that only male veterans with CAD were included in this study
    • Nathan Goodyear
       
      The authors here present Total Testosterone as a "confounding" value
    • Nathan Goodyear
       
      This would be HSD-II
  • the studies that failed to find an association between testosterone and CRP used an older population group
  • low testosterone may influence the severity of CAD by adversely affecting the mediators of the inflammatory response such as high‐sensitivity C‐reactive protein, interleukin‐6, and tumor necrosis factor–α
  •  
    Good review of Testosterone and CHD.  Low T is associated with increased all cause mortality and cardiovascular mortality, CAD, CHF, type II diabetes, obesity, increased IMT,  increased severity of CAD and CHF.  Testosterone replacement in men with low T has been shown to improve exercise tolerance in CHF, improve insulin resistance, improve HgbA1c and lower BMI in the obese.
Nathan Goodyear

An Empirical Evaluation of Guidelines on Prostate-specific Antigen Velocity in Prostate... - 0 views

  • men with a high PSA velocity (rate of change of PSA level)—greater than 0.35 ng mL−1 y−1—should consider biopsy even if absolute level of PSA is very low.
  • like other authors, we found strong evidence for a univariate association between PSA velocity and positive biopsy
  • we also found that PSA velocity does not add important predictive value to PSA and other standard predictors; in other words, we did not find that the use of a PSA velocity criterion for biopsy would improve clinical decision making
  •  
    This is the study that many have used to discredit psa velocity, but that is cherry picking the authors conclusions.  The authors did find an association with a positive psa velocity and + prostate biopsy.  Not useless, but useful in the right context.
Nathan Goodyear

Impact of Low Testosterone on Response to Treatment ... [Urology. 2014] - Pub... - 0 views

  •  
    Here is where science and particularly conclusions fail the public.  The authors conclusions are that tadalifl improves ED and sexual function irrespective of Testosterone levels.  However, the results say something different.  The group with normal Testosterone responded better versus the low Testosterone group.  This difference didn't reach statistical significance though.  This lack of statistical significance does not exclude the fact that there indeed was a difference.  The authors conlcusions take no part in reporting the whole truth, just that which supports their hypothesis. The diagnosis of low T in this study was < 300 ng/dl
Nathan Goodyear

Progesterone metabolites in breast cancer - 0 views

  • In breast tumor tissue and tumorigenic cell lines, 5α-reductase activity and mRNA expression are significantly higher, whereas 3α- and 20α-HSO activities and mRNA expression are significantly lower than in normal breast tissue and nontumorigenic cells
  • Studies using various breast cell lines have shown that 5αP and 3αHP have opposing actions in terms of cell proliferation and adhesion; 5αP stimulates cell proliferation (through increased mitosis and decreased apoptosis) and cell detachment, whereas 3αHP suppresses cell proliferation (through decreased mitosis and increased apoptosis) and detachment
  • the paracrine/ autocrine functions of 5αP are cancer-promoting and those of 3αHP are cancer-inhibiting
  •  
    Awesome article on progesterone metabolism in breast cancer.  The author, weibe, describes 2 categories of progesterone metabolites in breast tissue: 5alpha-pregnanes and 4-pregnenes.  The author describes 3 primary enzymes that control the balance between these 2 metabolites--5alpha reductase, 3alpha-HSO, and 20alpha-HSO.  The resultant balance of 5alpha-dihydroprogesterone and 3alpha-dihydroprogesterone helps to determine the cancer potential of breast tissue.
Nathan Goodyear

Concomitant Dietary Supplement and Prescription Medication Use Is Prevalent among US Ad... - 0 views

  •  
    Study worries over the risks of supplements and prescription drugs.  The author should worry more over the lack of knowledge by physicians of the health benefits of supplements.  Instead of focusing on the prescriptions themselves, how about focusing on the supplements to reduce the need for the prescriptions.  This authors focus is all wrong.   Obviously, the patient needs to be forthcoming with his/her physician about all supplements that they are on.  
Nathan Goodyear

Inflammatory and Cardiometabolic Risk on Obesity: Role of Environmental Xenoestrogens: ... - 0 views

  •  
    Study finds heavy presence of xenoestrogens in obese Portuguese women, both pre menopause and post menopause.  This study only looked at obese women; it would be nice to have a control of thin women to contrast the plasma and adipose xenoestrogen levels.  The authors found the presence of xenoestrogens in plasma in pre menopause women to be a 10 year predictor of cardiovascular disease risk in these women.  The authors also found increased Xenoestrogen levels to be associated with metabolic dysfunction and inflammation.
Nathan Goodyear

Evaluation of gabapentin in management of hot flushes in postmenopausal women - 0 views

  •  
    Study finds non-hormonal therapy to manage hot flashes in postmenopausal women--drug them.  The authors of this study, looked to gabapentin, also known as neurontin to treat hot flashes.  Instead of looking at the causes: hormone imbalance, stress... these authors looked to a sedating drug.  The dosing of neurontin was 900 mg.   Most can't stand at this dose.  This study points to the lunacy in the research today.  Very soon, there will be the walking dead among us.  They will be the walking doped instead of dead.
Nathan Goodyear

Review of high-dose intravenous vitami... [Asia Pac J Clin Oncol. 2014] - PubMed - NCBI - 0 views

  •  
    Study reviews the studies of IV vitamin C and cancer.  The authors discuss the mechanism of action of the high dose vitamin C.  The authors are correct in their conclusion that a large body of evidence is lacking and that the majority are case study.  However, to even discount these in the face of the safety and the reduction in side effects associated with chemotherapy by IV vitamin C would be unacceptable. To delay recommendation due to a full lack of understanding would be unacceptable as well.   No deaths have been reported due to IV vitamin C.  Contrast this with chemotherapy.  However, case studies have pointed to IV vitamin C as a positive tool to attach cancer.  
Nathan Goodyear

Late-onset hypogonadism among old and middle-aged males with predia... - PubMed - NCBI - 0 views

  •  
    Only abstract available here.  Study of Polish men found lowered Testosterone in men with pre diabetes.  The authors used the term "late onset hypogonadism" here.  An inverse association was found between calculated free Testosteorne and HgbA1c.  The authors conclusion says it all: routine screening of Testosterone in men with pre-diabetes is recommended.
Nathan Goodyear

Unintended effects of statins from observational studies in the general population: sys... - 0 views

  • A markedly increased risk of myopathy was observed
  • One cohort study (Women’s Health Initiative) of higher quality and larger sample size found stronger evidence of an increased risk of self-reported T2DM (OR=1.47; 95% CI 1.32 to 1.64) for the groups of women who reported statin use at baseline and three years later
  • Hippisley-Cox et al. found an increased risk of liver enzyme changes
  • ...5 more annotations...
  • weak evidence of an increased risk of type 2 diabetes mellitus (T2DM) was observed
  • Smeeth et al. found an increased risk of incident liver disease in the first year after the index date
  • The cumulative incidence of T2DM after three years of statin treatment was 6.25%, corresponding to an excess risk of 2.25%
  • We found no increased risk of peripheral neuropathy, depression, common eye diseases, renal disorders or arthritis associated with taking statins. Studies of higher quality did not show previously reported protective effects of statins on fractures, venous thrombo-embolism or pneumonia
  • There was evidence of an increase in myopathy, raised liver enzymes and diabetes.
  •  
    Statin use associated with increased myopathy, liver dysfunction, and type II Diabetes.  The authors conclude that the absolute risk is very low, yet OR was 1.47 for type II Diabetes (translated 47% increased odds of developing Diabetes as a result of statins) and OR of 2.63 in risk of myopathy (translated 163% increased odds of developing myopathy as a result of statins).  Seems the authors "low risk" statement is just applies to those without symptoms/side effects.  Physicians need to do a better job of understanding risks and customizing therapies.
Nathan Goodyear

Testosterone in Men with Advanced Li... [J Gastroenterol Hepatol. 2014] - PubMed - NCBI - 0 views

  •  
    published ahead of print.  The authors conclude that the Testosterone therapy in hypogonadal men with cirrhosis requires further study.  They, the authors, state that the risk of Testosterone and hepatocellular carcinoma is overstated.  This risk is associated with oral Testosterone replacement and thus in that light is not overstated.  The majority of treatment strategies today employ none oral routes of administration which would support their statement.
Nathan Goodyear

Testosterone and benign prostatic hyperplasia Jarvis TR, Chughtai B, Kaplan SA, - Asian... - 0 views

  • The prevalence of hypogonadism (often defined as serum testosterone &lt; 300 ng dl−1 ) ranges from 6% [10] to as high as 38%
  • The process of BPH, however, continues as men age and despite the fact their serum testosterone decreases
  • Liu et al. [12] demonstrated that in a group of older males (mean age 59.8 years) that there was not a significant correlation of serum testosterone levels (total, free or bioavailable) with either prostate volume or International Prostate Symptom Score (IPSS)
  • ...11 more annotations...
  • in eugonadal men, studies have demonstrated that the prostate can increase in volume by approximately 12%
  • There seems to be little doubt that the treatment with testosterone of a young hypogonadal male leads to significant growth of the prostate
  • Behre et al. [22] demonstrated increased prostate volume and prostate-specific antigen (PSA) levels in hypogonadal men
  • Most studies, however, have shown no effect of exogenous androgens on PSA or prostate volume for older hypogonadal males
  • They argue that the prostate is relatively insensitive to changes in androgen concentration at normal levels or in mild hypogonadism because the AR is saturated by androgens and therefore maximal androgen-AR binding is achieved. Conversely, the prostate is very sensitive to changes in androgen levels when testosterone is low
  • saturation model
  • visceral obesity (one of the most significant components of metabolic syndrome) is associated with prostate volume and influences prostate growth during TRT.
  • This hypothesis of inflammation induced LUTS is also argued to be a mechanism for improvement of LUTS with PDE5I
  • The concept, therefore, that treatment with TRT of hypogonadal males with metabolic syndrome might lead to improvement/stabilization of their LUTS, appears to be confirmed in recent work by Francomano et al.
  • There was also an improvement in components of the patient's metabolic syndrome (such as BMI, waist circumference, hemoglobin A1c [HbA1c], insulin sensitivity, and lipid profile) as well as inflammatory markers and C-reactive protein.
  • They concluded that TRT was safe in this group of men, and hypothesize that TRT mitigates the pro-inflammatory factors associated with metabolic syndrome.
  •  
    Authors review the literature behind Testosterone and BPH.  The authors highlight the 4 proposed theories behind BPH: Testosterone, Estrogen, inflammation, and metabolic.   The conclusion is mixed: pointing out that no high level of evidence exists on either side of the debate of Testosterone and BPH.
Nathan Goodyear

N-Acetylcysteine for Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis o... - 0 views

  • compared effects of NAC with placebo or metformin in women with PCOS
  • NAC significantly improved rates of live births and spontaneous ovulation compared to placebo in women with PCOS
  • we found no evidence of effects of NAC on improving menstrual regularity, acne, hirsutism, BMI, fasting insulin, fasting glucose, or HOMA-IR
  • ...3 more annotations...
  • NAC was not associated with greater benefits to metformin for improving pregnancy rate, spontaneous ovulations, and menstrual regularity
  • Metformin also improved the BMI, total testosterone, insulin level, and lipid levels compared to NAC
  • All the studies were of short duration (three months)
  •  
    Data review finds NAC improves pregnancy rates and ovulation rates in women with PCOS against placebo.  Meta-analysis revealed limited studies on the topic.  When compared to metformin, there was no difference found.  Though, one wonders if attacking insulin resistance through proper diet and additional neutraceutical approach would negate that.  The reason?  NAC and metformin are working in different biochemical pathways.  The authors here seem to not realize this. It appears that they think NAC and metormin are both working in the same manner, but they don't.  The fact that there is still benefit found compared to placebo, despited the authors lack of understanding of what NAC is and does is a positive.
Nathan Goodyear

Testosterone level in men with type 2 diabetes mellitus and related metabolic... - 0 views

  • defined by consistent symptoms and signs of androgen deficiency, and an unequivocally low serum testosterone level
  • the threshold serum testosterone level below which adverse clinical outcomes occur in the general population is not known
  • most population-based studies use the serum testosterone level corresponding to the lower limit, quoted from 8.7 to 12.7&nbsp;nmol/L, of the normal range for young Caucasian men as the threshold
    • Nathan Goodyear
       
      this equals 251 to 366 in serum Total Testosterone
  • ...57 more annotations...
  • Researchers tried to examine whether serum total or free testosterone would be a better/more reliable choice when studying the effect of testosterone. The results were mixed. Some reported significant associations of both serum total and free testosterone level with clinical parameters25, whereas others reported that only serum free testosterone26 or only serum total testosterone6 showed significant associations.
  • −0.124&nbsp;nmol/L/year in serum total testosterone
    • Nathan Goodyear
       
      this equates to a 4 ng/dl decline annually in total Testosterone.
  • In experimental studies, androgen receptor knockout mice developed significant insulin resistance rapidly
  • In mouse models, testosterone promoted differentiation of pluripotent stem cells to the myogenic lineage
  • testosterone decreased insulin resistance by enhancing catecholamine induced lipolysis in&nbsp;vitro, and reducing lipoprotein lipase activity and triglyceride uptake in human abdominal tissue in&nbsp;vivo
  • by promoting lipolysis and myogenesis, testosterone might lead to improved insulin resistance
  • testosterone regulated skeletal muscle genes involved in glucose metabolism that led to decreased systemic insulin resistance
  • In the liver, hepatic androgen receptor signaling inhibited development of insulin resistance in mice
  • independent and inverse association of testosterone with hepatic steatosis shown in a cross-sectional study carried out in humans
  • In short, androgen improves insulin resistance by changing body composition and reducing body fat.
  • Although a low serum testosterone level could contribute to the development of obesity and type&nbsp;2 diabetes through changes in body composition, obesity might also alter the metabolism of testosterone
  • In obese men, the peripheral conversion from testosterone to estrogen could attenuate the amplitude of luteinizing hormone pulses and centrally inhibit testosterone production
  • leptin, an adipokine, has been shown to be inversely correlated with serum testosterone level in men
  • Leydig cells expressed leptin receptors and leptin has been shown to inhibit testosterone secretion, suggesting a role of obesity and leptin in the pathogenesis of low testosterone
    • Nathan Goodyear
       
      So what is "unequivocal"?
  • Baltimore Longitudinal Study of Aging (BLSA) cohort made up of 3,565 middle-class, mostly Caucasian men from the USA, the incidence of low serum total testosterone increased from approximately 20% of men aged over 60&nbsp;years, 30% over 70&nbsp;years, to 50% over 80&nbsp;years-of-age
  • 30–44% sex hormone binding globulin (SHBG)-bound testosterone and 54–68% albumin-bound testosterone
  • As the binding of testosterone to albumin is non-specific and therefore not tight, the sum of free and albumin-bound testosterone is named bioavailable testosterone, which reflects the hormone available at the cellular level
  • Serum total testosterone is composed of 0.5–3.0% of free testosterone unbound to plasma proteins
  • alterations in SHBG concentration might affect total serum testosterone level without altering free or bioavailable testosterone
  • listed in Table​T
  • A significant, independent and longitudinal effect of age on testosterone has been observed with an average change of −0.124&nbsp;nmol/L/year in serum total testosterone28. The same trend has been shown in Europe and Australia
  • Asian men residing in HK and Japan, but not those living in the USA, had 20% higher serum total testosterone than in Caucasians living in the USA, as shown in a large multinational observational prospective cohort of the Osteoporotic Fractures in Men Study
  • subjects with chronic diseases consistently had a 10–15% lower level compared with age-matched healthy subjects
  • In Caucasians, the mean serum total testosterone level for men in large epidemiological studies has been reported to range from 15.1 to 16.6&nbsp;nmol/L
  • Asians, higher values, ranging from 18.1 to 19.1&nbsp;nmol/L, were seen in Korea and Japan
  • Chinese middle-aged men reported a similar mean serum testosterone level of 17.1&nbsp;nmol/L in 179 men who had a family history of type&nbsp;2 diabetes and 17.8&nbsp;nmol/L in 128 men who had no family history of type&nbsp;2 diabetes
  • The reduction of total testosterone was 0.4% per year in both groups
  • HK involving a cohort of 1,489 community-dwelling men with a mean age of 72&nbsp;years, a mean serum total testosterone of 19.0&nbsp;nmol/L was reported
  • pro-inflammatory factors, such as tumor necrosis factor-α in the testes, could locally inhibit testosterone biosynthesis in Leydig cells47, and testosterone treatment in men was shown to reduce the level of tumor necrosis factor-α
  • In Asians, a genetic deletion polymorphism of uridine diphosphate-glucuronosyltransferase UGT2B17 was associated with reduced androgen glucuronidation. This resulted in higher level of active androgen in Asians as compared to Caucasians, as Caucasians' androgen would be glucuronidated into inactive forms faster.
  • Compared with Caucasians, the frequency of this deletion polymorphism of UGT2B17 was 22-fold higher in Asian subjects
  • Other researchers have suggested that environmental, but not genetic, factors influenced serum total testosterone
  • The basal and ligand-induced activity of the AR is inversely associated with the length of the CAG repeat chain
  • In the European Male Aging Study, increased estrogen/androgen ratio in association with longer AR CAG repeat was observed
  • a smaller number of AR CAG repeat had been shown to be associated with benign prostate hypertrophy and faster prostate growth during testosterone treatment
  • In India, men with CAG ≤19 had increased risk of prostate cancer
  • the odds of having a short CAG repeat (≤17) were substantially higher in patients with lymph node-positive prostate cancer than in those with lymph node-negative disease or in the general population
  • assessing the polymorphism at the AR level could be a potential tool towards individualized assessment and treatment of hypogonadism.
  • In elderly men, there was reduced testicular response to gonadotropins with suppressed and altered pulsatility of the hypothalamic pulse generator
  • a significant, independent and longitudinal effect of age on serum total testosterone level had been observed
  • A significant graded inverse association between serum testosterone level and insulin levels independent of age has also been reported in Caucasian men
  • Low testosterone is commonly associated with a high prevalence of MES
  • most studies showed that changes in serum testosterone level led to changes in body composition, insulin resistance and the presence of MES, the reverse might also be possible
  • MES predicted a 2.6-fold increased risk of development of low serum testosterone level independent of age, smoking and other potential confounders
  • Other prospective studies have shown that development of MES accelerated the age-related decline in serum testosterone level
  • In men with type&nbsp;2 diabetes, changes in serum testosterone level over time correlated inversely with changes in insulin resistance
  • weight loss by either diet control or bariatric surgery led to a substantial increase in total testosterone, especially in morbidly obese men, and the rise in serum testosterone level was proportional to the amount of weight lost
  • To date, published clinical trials are small, of short duration and often used pharmacological, not physiological, doses of testosterone
  • In the population-based Osteoporotic Fractures in Men Study cohort from Sweden, men in the highest quartile of serum testosterone level had the lowest risk of cardiovascular events compared with men in the other three quartiles (hazard ratio [HR] 0.70
  • low serum total testosterone was associated with a significant fourfold higher risk of cardiovascular events when comparing men from the lowest testosterone tertile with those in the highest tertile
  • Shores et&nbsp;al. were the first to report that low serum testosterone level, including both serum total and free testosterone, was associated with increased mortality
  • low serum total testosterone predicted increased risk of cardiovascular mortality with a HR of 1.38
  • low serum total testosterone increased all-cause (HR 1.35, 95% CI 1.13–1.62, P&nbsp;&lt;&nbsp;0.001) and cardiovascular mortality (HR 1.25
  • European Association for the Study of Diabetes 2013 suggested there was an inverse relationship between serum testosterone level and acute myocardial infarction
  • Diabetic men in the highest quartile of serum total testosterone had a significantly reduced risk of acute MI when compared with those in the lower quartiles
  • serum total testosterone level in the middle two quartiles at baseline predicted reduced incidence of death compared with having the highest and lowest levels
  •  
    Nice review of Testosterone levels and some of the evidence linking Diabetes with low T.  However, the conclusion by the authors regarding what is causing the low T in men with Diabetes is baffling.  The literature does not point to one cause, it is clearly multifactorial--obesity, inflammation, high aromatase activity...I would suggest the authors continue their readings in the manner.
Nathan Goodyear

Muscle Hypertrophy 2011 - 0 views

  • mechanical tension, muscle damage and metabolic stress are the three primary factors that promote hypertrophy from exercise
  • The mechanical tension is directly related to intensity of the exercise, which is the key to stimulating muscle growth
  • Muscle damage, that leads to muscle soreness, from exercise training initiates an inflammatory response, which activates satellite cells growth processes
  • ...6 more annotations...
  • metabolic stress that is a result of the byproducts of anaerobic metabolism (i.e., hydrogen ions, lactate, inorganic phosphates) is now also believed to promote hormonal factors leading to muscle hypertrophy
  • The upper extremities tend to show more growth earlier then the lower body
  • Maximal growth occurs with loads between 80-95% of 1 repetition maximum
  • weightlifters and powerlifters show more favorable hypertrophy of type II (fast twitch) muscle fibers
  • body builders appear to have comparable hypertrophy in both the type I (slow twitch) and type II muscle fibers
  • Multi-joint exercises have been shown to produce larger increases of anabolic hormones than single-joint exercises
  •  
    Review of the physiology of muscle building.  The authors review the evidence behind the types of muscle building exercises and the physiology responsible for muscle hypertrophy.  The authors point to Schoenfeld's description of mechanical tension, muscle damage, and metabolic stress to build muscle.
1 - 20 of 238 Next › Last »
Showing 20 items per page