Skip to main content

Home/ Groups/ Dr. Goodyear
Rss Feed
Sort By: Most Recent | Popular Filter: All | Bookmarks | Topics Simple Middle
Nathan Goodyear

In older men an optimal plasma testo... [J Clin Endocrinol Metab. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24257908

Testosterone DHT cardiovascular disease heart men estradiol E2 dihydrotestosterone male hormone hormones

shared by Nathan Goodyear on 03 Feb 14 - No Cached
  • Nathan Goodyear on 03 Feb 14
     
    Study finds that "midrange" Testosterone and DHT associated with a reduced ischemic heart disease and death rate.  No association was found with Estradiol.  One flaw of this study is in their use of serum.
Nathan Goodyear

The relationship between sleep disorders and testosterone in men Wittert G - Asian J An... - 0 views

www.ajandrology.com/article.asp

sleep disorders testosterone men male hormone hormones

shared by Nathan Goodyear on 03 Feb 14 - No Cached
  • Nathan Goodyear on 03 Feb 14
     
    Low Testosterone found to disrupt restful sleep in men.  However, in contrast, Testosterone doping leads to sleep disruption as well.  I love how the authors describe it: ...in supra therapeutic doses, or in the context abuse."
Nathan Goodyear

Morning free and total testosterone in HIV-infected men: implications for the assessmen... - 0 views

www.ncbi.nlm.nih.gov/...PMC3900935

free Testosterone HIV men hormone hormones male SHBG

shared by Nathan Goodyear on 03 Feb 14 - No Cached
  • Nathan Goodyear on 03 Feb 14
     
    low T is found in 20-70% of men with HIV.  What is interesting about this article is that Total Testosterone was found to be a poor assessment of biological active Testosterone.  Free Testosterone assessed in the am was shown to be a better functional assessment in these men.  Serum is a poor choice though.  The process of equilibrium dialysis to calculate free Testosterone is filled with variables that will effect reliability.  Increases SHBG was found associated.
Nathan Goodyear

Effects of physiologic testosterone therapy on qua... [Menopause. 2014] - PubMed - NCBI - 1 views

www.ncbi.nlm.nih.gov/...24473536

testosterone therapy menopause premature ovarian failure women

shared by Nathan Goodyear on 03 Feb 14 - No Cached
  • Nathan Goodyear on 03 Feb 14
     
    12 months of Testosterone in women with premature ovarian failure found no benefit in quality of life measures.  Testosterone is being marketed and touted as a means to help women through menopause.  This study, though no side effects found, no benefit found.
Nathan Goodyear

The effect of statins on testosterone in men and women, a systematic review and meta-an... - 0 views

www.ncbi.nlm.nih.gov/...PMC3621815

Statins Testosterone cholesterols androgens cardiovascular

shared by Nathan Goodyear on 17 Jan 14 - No Cached
  • Nathan Goodyear on 17 Jan 14
     
    Meta-analysis finds that statins lower Testosterone levels in both men and women.  
Nathan Goodyear

PLOS ONE: Effect of Melatonin on Tumor Growth and Angiogenesis in Xenograft Model of Br... - 0 views

www.plosone.org/...10.1371%2Fjournal.pone.0085311

breast cancer melatonin hormone hormones

shared by Nathan Goodyear on 31 Jan 14 - No Cached
  • Nathan Goodyear on 31 Jan 14
     
    In vivo study finds melatonin reduced tumor growth, proliferation, and inhibited angiogenesis in breast cancer model.
Nathan Goodyear

BMC Medicine | Full text | Testosterone therapy and cardiovascular events among men: a ... - 0 views

www.biomedcentral.com/...108

testosterone therapy treatment cardiovascular events disease low T men male hormone hormones

shared by Nathan Goodyear on 31 Jan 14 - No Cached
  • Nathan Goodyear on 31 Jan 14
     
    Meta-analysis of mainly older men finds increased cardiovascular events with Testosterone therapy.
Nathan Goodyear

Adverse Events Associated with Testosterone Administration - NEJM - 0 views

www.nejm.org/...NEJMoa1000485

Testosterone therapy low T treatment men male hormone hormones

shared by Nathan Goodyear on 31 Jan 14 - No Cached
  • Nathan Goodyear on 31 Jan 14
     
    Study of 209 men > 65 on Testosterone therapy was stopped early due to increase cardiovascular adverse events  The likely reason was the amazingly high dosing.  The men in this study were just doped.  The dosing was 100 mg + which is in stark contrast to the 5-10 mg daily production of a young man at 22.
Nathan Goodyear

PLOS ONE: Increased Risk of Non-Fatal Myocardial Infarction Following Testosterone Ther... - 0 views

www.plosone.org/...10.1371%2Fjournal.pone.0085805

Testosterone therapy cardiovascular disease men male hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • For all TT prescription subjects combined, the post/pre prescription rate ratio for MI (RR)was 1.36
  • In men aged 65 years and older the RR was 2.19 (1.27, 3.77), while in men under age 65 years the RR was 1.17
  • increasing RR with increasing age.
  • ...20 more annotations...
  • The RRs were 0.95 (0.54, 1.67) under 55 years
  • 1.35 (0.77, 2.38) at 55–59
  • 1.29 (0.71, 2.35) at 60–64,
  • 1.35 (0.44, 4.18) at 65–69, 1.62
  • 3.43 (1.54, 7.66) at 75 years and older
  • The adjusted post/pre RR for PDE5I across all ages was 1.08
  • For TT prescription, in men under age 65 years, the RR was 2.90 (1.49, 5.62) for those with a history of heart disease and 0.90 (0.61, 1.34) for those without
  • In men aged 65 year and older, the RR was 2.16 (0.92, 5.10) for those with a history of heart disease and 2.21 (1.09, 4.45) for those without.
  • Among men aged 65 years and older, we observed a two-fold increase in the risk of MI in the 90 days after filling an initial TT prescription
  • Among younger men with a history of heart disease, we observed a two to three-fold increased risk of MI in the 90 days following an initial TT prescription and no excess risk in younger men without such a history
  • Among older men, the two-fold increased risk was associated with TT prescription regardless of cardiovascular disease history
  • our own findings appear consistent with a higher frequency of thrombotic events following TT prescription among men with more extensive coronary vascular disease.
  • Our findings are consistent with a recent meta-analysis of placebo-controlled randomized trials of testosterone therapy lasting 12 or more weeks among mainly older men, which reported that testosterone therapy increased the risk of adverse cardiovascular-related events (OR = 1.54, 95%CI:1.09, 2.18), as well as serious adverse cardiovascular-related events (OR = 1.61, 95%CI:1.01, 2.56) which included myocardial infarction along with other conditions
  • This association appeared unrelated to average baseline testosterone level (p = 0.70) but varied by source of funding (p = 0.03), with a stronger summary effect in a meta-analysis of studies not funded by the pharmaceutical industry (OR = 2.06, 95%CI:1.34, 3.17) compared with studies funded by the pharmaceutical industry
    • Nathan Goodyear
      Nathan Goodyear on 30 Jan 14
       
      This supports prior analysis that studies done by pharmaceutical corps will be more favorable to their product(s) than those independently funded.  This is called bias.
  • the evidence supports an association between testosterone therapy and risk of serious, adverse cardiovascular-related events–including non-fatal myocardial infarction–in men
  • there is some evidence that low endogenous testosterone levels may also be positively associated with cardiovascular events
  • effects of endogenous and exogenous testosterone may differ. Exogenous testosterone (TT) is associated with physiologic changes that predispose to clotting and thrombotic disorders including increased blood pressure [18], polycythemia [19], reductions in HDL cholesterol [18], [20], and hyperviscosity of the blood and platelet aggregation. [20]–[23]; TT also increases circulating estrogens [24], [25] which may play a role in the observed excess of adverse cardiovascular-related events, given that estrogen therapy has been associated with this excess in both men and women
  • did not include information on the serologic or diagnostic indications for treatment.
  • no association between PDE5I prescriptions and the risk of MI
  • Recently TT has been increasing extraordinarily rapidly, including among younger men and among those without hormone measurement
  • Nathan Goodyear on 30 Jan 14
     
    New cohort study finds increased risk of Testosterone in men > 65 and those : these are based in marketing-based medicine not evidence based medicine.
Nathan Goodyear

http://www.medicalbiostatistics.com/rr-or-etc.pdf - 0 views

www.medicalbiostatistics.com/rr-or-etc.pdf

statistics

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    discussion of the common tools to discuss statistics.
Nathan Goodyear

Incidence of Childhood Obesity in the United States - NEJM - 0 views

www.nejm.org/...NEJMoa1309753

obesity children

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    Obesity starts young.
Nathan Goodyear

The Dark Side of Testosterone Deficiency: III. Cardiovascular Disease - Traish - 2013 -... - 0 views

onlinelibrary.wiley.com/...full

low T Testosterone CVD cardiovascular disease men male hormone hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    More recent articles have been published, but this review article reviews the link between low T and cardiovascular disease in men.
Nathan Goodyear

The Dark Side of Testosterone Deficiency: I. Metabolic Syndrome and Erectile Dysfunctio... - 0 views

onlinelibrary.wiley.com/...full

low T Testosterone metabolic syndrome ED metabolic syndrome obesity men male hormone hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    Article reviews the link between obesity, low T, metabolic syndrome and ED.  ED has been shown to be predictive of CVD by 3-5 years.  
Nathan Goodyear

The Dark Side of Testosterone Deficiency: II. Type 2 Diabetes and Insulin Resistance - ... - 0 views

onlinelibrary.wiley.com/...full

low T Testosterone diabetes insulin resistance IR metabolic syndrome metabolic syndrome men male hormone hormones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    low Testosterone linked to insulin resistance, type II Diabetes, and increased  metabolic syndrome.  Low T is linked to increased visceral fat in this study.  
Nathan Goodyear

Testosterone and type 2 diabetes in men. [Aging Male. 2014] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...24471529

low T Testosterone diabetes men male hormone hormones glucose

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    low Testosterone was indecently associated with an elevated fasting glucose, but weakly associated with type II Diabetes in 991 male veterans.
Nathan Goodyear

The dialectic role of progesterone. [Maturitas. 2009] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...19171445

progesterone metabolite metabolites. hormone hormones receptor PR-A PR-B

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    knowledge of progesterone and its metabolites are important in the use of hormones.  As the authors concluded here: "natural steroids should not be disparaged...an update on endocrinological knowledge and experience is rather mandatory for gynecologists".  There in lies the problem.  The IOM has shown that the average physician practices at a level of 17 years behind the current scientific knowledge and the environment created by medical governing bodies discourages questions, so as to protect the system.
Nathan Goodyear

Activity and expression of progesterone metabolizing 5α-reductase, 20α-hydrox... - 0 views

www.ncbi.nlm.nih.gov/...PMC154104

progesterone metabolites breast cancer 5alpha-reductase 5-alpha pregnene 5-alpha pregnenes 4-pregnene 4-pregnenes

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Exposure of human breast cell lines (MCF-7, MCF-10A, and ZR-75-1) to 5α-pregnanes results in changes associated with neoplasia, including increased proliferation and decreased attachment [1], depolymerization of F-actin [2] and decreases in adhesion plaque-associated vinculin
  • Exposure to 4-pregnenes results, in general, in opposite (anti-cancer-like) effects
  • 5αR1 has been detected in various androgen-independent organs, such as the liver and brain
  • ...10 more annotations...
  • 5αR2 has been found predominantly in androgen-dependent organs, such as epididymis and prostate
  • The 5α-pregnanes:4-pregnenes ratio was about 8-fold higher in tumorous than in nontumorous breast tissue after an 8-hour incubation with [14C]progesterone
  • Studies with breast cell lines, showing that 5α-pregnanes stimulate proliferation and decrease attachment of cells
  • both tissue and breast cell line studies suggest that an elevated level of progesterone 5α-reductase activity may be an indicator of breast tumorigenesis, regardless of presence or absence of ER and/or PR
  • 5αR1 is the main isoform expressed in human breast carcinomas [29] and that 5αR2 may not be associated with risk of breast cancer
  • the differences in 5α-pregnane production between the cells is due primarily to a difference in 5αR1 expression
  • As in the case of 5α-reductase activity, the presence or absence of ER and PR do not appear to be related to 5α-reductase expression.
  • the conversion of progesterone to the cancer promoting 5α-pregnanes is significantly higher in the human tumorigenic breast cell lines
  • lthough both 5αR1 and 5αR2 are expressed by these cells, the elevated 5α-reductase activity appears to be the result of significantly greater expression of 5αR1
  • Changes in progesterone metabolizing enzyme expression (resulting in enzyme activity changes) may be responsible for promoting breast cancer progression due to increased production of tumor-promoting 5α-pregnanes and decreased production of anti-cancer 20α – and 3α-4-pregnenes
  • Nathan Goodyear on 30 Jan 14
     
    balance of enzyme production between 5alpha-reductase and 20alpha-hydroxysteroid oxidoreductase and 3alpha(beta)-hydroxysteroid oxidoreductase play role in carcinogenesis and proliferation in the balance of production of progesterone metabolites. The 5alpha pregnenes are pro carcinogenic  and the 4-pregnenes are anti carcinogenic.
Nathan Goodyear

Progesterone metabolites regulate induction, growth, and suppression of estrogen- and p... - 0 views

www.ncbi.nlm.nih.gov/...PMC3706910

progesterone metabolites metabolite 5-alpha pregnene 5-alpha pregnenes 5alpha-dihydroprogesterone 4-pregnene 4-pregnenes 3alpha-dihydroprogesterone breast cancer ER PR hormone hormones receptors estrogen

shared by Nathan Goodyear on 28 Jan 14 - No Cached
  • in vitro studies had shown that the progesterone metabolites, 5α-dihydroprogesterone (5αP) and 3α-dihydroprogesterone (3αHP), respectively, exhibit procancer and anticancer effects on receptor-negative human breast cell lines
  • Onset and growth of ER/PR-negative human breast cell tumors were significantly stimulated by 5αP and inhibited by 3αHP
  • When both hormones were applied simultaneously, the stimulatory effects of 5αP were abrogated by the inhibitory effects of 3αHP and vice versa
  • ...31 more annotations...
  • Treatment with 3αHP subsequent to 5αP-induced tumor initiation resulted in suppression of further tumorigenesis and regression of existing tumors
  • Tumorigenesis of ER/PR-negative breast cells is significantly enhanced by 5αP and suppressed by 3αHP, the outcome depending on the relative concentrations of these two hormones in the microenvironment in the breast regions
  • The findings show that the production of 5αP greatly exceeds that of 3αHP in ER/PR-negative tumors and that treatment with 3αHP can effectively block tumorigenesis and cause existing tumors to regress
  • hypothesis that a high 3αHP-to-5αP concentration ratio in the microenvironment may foster normalcy in noncancerous breast regions.
  • a large proportion (about 30% to 60%) of breast tumors are ER and/or PR negative
  • about 90% of normal proliferating breast epithelial cells are receptor negative
  • Our previous in vitro studies had shown that breast tissues and cell lines readily convert progesterone to 5α-pregnanes, such as 5αP, and delta-4-pregnenes, such as 3αHP (Figure ​(Figure1),1), and that tumorous breast tissues [15] and tumorigenic breast cell lines [16] produce higher levels of 5αP and lower levels of 3αHP than do normal breast tissues and nontumorigenic cell lines
  • The progesterone metabolism studies suggested that increases in 5αP and decreases in 3αHP production accompany the shift toward breast cell neoplasia and tumorigenicity
  • In vitro studies on five different human breast cell lines showed that cell proliferation and detachment are significantly increased by 5αP and decreased by 3αHP
  • the prevailing theory of hormonal regulation of breast cancer, as well as hormone-based therapies, revolves around estrogen and/or progesterone and ER/PR-positive breast cells and tumors.
  • Not only do these "receptor-negative" breast cancers fail to benefit from current hormonal therapies, but they also generally exhibit more-aggressive biologic behaviors and poorer prognosis than the receptor-positive ones
  • The results of the studies reported here show for the first time that the progesterone metabolites, 5αP and 3αHP, act as hormones that regulate ER/PR-negative breast tumor formation, growth, and regression
  • The onset of the ER/PR-negative human breast cell tumors in mice was considerably accelerated, and the growth significantly stimulated, by just one or two applications of 5αP
  • In contrast, 3αHP retarded onset of tumor formation, suppressed tumor growth, and inhibited or regressed existing 5αP-induced tumors
  • When both hormones were administered simultaneously, the effects of one were abrogated by the effects of the other.
  • The 5αPR and 3αHPR (which are associated with the plasma membranes of both ER/PR-positive [19] and ER/PR-negative [29] cells) are distinct from each other and from known ER, PR, androgen, and corticosteroid receptors, and lack affinity for other steroids, such as progesterone, estrogen, androgens, corticosteroids, and other progesterone metabolites
  • Levels of 5αPR are upregulated by 5αP itself and estradiol, and downregulated by 3αHP in both ER/PR-positive and -negative cells
  • ndications are that 5αP acts via the surface receptor-linked mitogen-activated protein kinase (MAPK; Erk1/2) pathway; 5αP significantly stimulates activation of Erk1/2 [30], increases the Bcl-2/Bax expression ratio [18] and actin depolymerization [31], and decreases expression of actin and adhesion plaque-associated vinculin [31], resulting in decreased apoptosis and increased mitosis and cell detachment
  • 3αHP appears to suppress protein kinase C (PKC), phospholipase C (PLC), Ca2+ mobilization (unpublished observations), and the Bcl-2/Bax expression ratio [18], and increases expression of the cell-cycle inhibitor p21 [18], resulting in increased apoptosis and decreased proliferation and detachment of breast cell lines.
  • serum from mice with tumors had significantly more 5αP than 3αHP
  • the tumors, which on average had about threefold higher concentrations of 5αP than the respective sera, and >10-fold higher 5αP than 3αHP levels
  • Previous in vitro metabolism studies showed that human breast tumor tissues convert significantly more progesterone to 5α-pregnanes like 5αP and less to 4-pregnenes like 3αHP than do paired normal (nontumorous) tissues
  • Similar differences in progesterone metabolism and enzyme gene expressions were observed between tumorigenic and nontumorigenic breast cell lines
  • breast carcinomas are able to synthesize progesterone
  • The current findings, along with the previous in vitro studies, suggest that the relative concentrations of 5αP and 3αHP in the breast microenvironment constitute important autocrine/paracrine determinants not only for tumorigenesis but also for potential regression of tumors and the maintenance of normalcy of ER/PR-negative breast cells/tissues.
  • Evidence presented here shows that a high concentration of 5αP, relative to 3αHP in the microenvironment, promotes initiation and growth of tumors, whereas a higher concentration of 3αHP, relative to 5αP, suppresses tumorigenesis and promotes normalcy
  • 5α-reductase and 5αPR levels are upregulated by 5αP
  • in the 3αHP-treated mice, the elevated 3αHP levels, relative to 5αP, in the microenvironment could have opposed progression to xenograft neoplasia by its inherent anticancer actions and the suppression of 5αP synthesis and 5αPR expression
  • the opposing actions of the progesterone metabolites also appear to exert some control over the estrogen-regulated effects on breast cancer by their ability to modulate ER numbers in ER-positive cells
  • because both ER/PR-negative and ER/PR-positive, as well as normal and tumorigenic human breast cell lines, have been shown to respond to 5αP and 3αHP in vitro, it is suggested that these endogenously produced progesterone metabolites may also play regulatory hormonal roles in ER/PR-positive breast cancers, as well as in the maintenance of normalcy in nontumorous breast tissues.
  • The in vivo data provide further evidence that progesterone metabolites, such as 5αP and 3αHP, deserve to be considered as active hormones in their own right, rather than inactive waste products
  • Nathan Goodyear on 28 Jan 14
     
    Progesterone metabolites and breast cancer
Nathan Goodyear

Genotoxic metabolites of estradio... [J Steroid Biochem Mol Biol. 2003] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...14623547

ER estrogen receptor metabolite metabolites breast cancer 3 4 quinones quinones

shared by Nathan Goodyear on 30 Jan 14 - No Cached
  • Nathan Goodyear on 30 Jan 14
     
    study finds estrogen metabolites are involved in carcinogenesis through the production of toxic metabolites 3,4 quinones.  The presence of Estrogen receptors were associated with increased tumor growth. ER was in fact ER alpha.  What is interesting is that ER beta is not expressed these ERKO animals.  This again points to ER beta's anti proliferative action.
Nathan Goodyear

Fragmented sleep accelerates tumor growth and progression through recruitment of tumor-... - 0 views

cancerres.aacrjournals.org/...0008-5472.CAN-13-3014.abstract

sleep cancer

shared by Nathan Goodyear on 29 Jan 14 - No Cached
  • Nathan Goodyear on 29 Jan 14
     
    Poor sleep effects immune system which effects tumor growth.
« First ‹ Previous 7041 - 7060 of 11108 Next › Last »
Showing 20▼ items per page
Join this group