A Set of Nonparametric Tests for Experiments with Lattice-Ordered Means: Theory, Programs, and Applications

In many factorial experiments where the factors have levels that are ordinal or quantitative, a researcher may predict that the mean response in certain treatments will be higher or lower than those in other treatments. One type of order that may be anticipated is called lattice order, where average response tends to increase (or decrease) as the levels of any one of the factors is increased, holding the others fixed. A Kendall-type statistic, which measures the degree of lattice order in the data, can also be used to carry out a test involving lattice-ordered means. In this article, tests for individual factors are developed to complement the overall test of lattice order, and the methods are then applied to relevant and current data. Programs in R and FORTRAN are included to carry out the tests.

Effect of soy in men with type 2 diabetes mellitus and subclinical hypogonadism: a randomised controlled study

Context: Isoflavones found in soy products have a chemical structure similar to estrogen, leading to concerns of an adverse estrogenic effect in men, particularly in those with type 2 diabetes mellitus (T2DM) who have low testosterone levels due to hypogonadism. Objective: The primary outcome was change in total testosterone levels. The secondary outcomes were the changes in glycaemia and cardiovascular risk markers. Design: Randomised double blind parallel study. Setting: Secondary care setting in UK. Participants: 200 men with T2DM with a total testosterone level≤12nmol/L Intervention: 15g soy protein with 66mg of isoflavones (SPI) or 15g soy protein alone without isoflavones (SP) daily as snack bars for three months. Results: There was no change in either total testosterone or in absolute free testosterone levels with either SPI or SP. There was an increase in TSH and reduction in fT4 (p<0.01) after SPI supplementation. Glycaemic control improved with a significant reduction in HbA1c (-4.19(7.29)mmol/mol,p<0.01) and HOMA-IR after SPI. Cardiovascular risk improved with a reduction in triglycerides, CRP and diastolic BP (p<0.05) with SPI versus SP supplementation. There was 6% improvement in 10-year coronary heart disease risk after three months of SPI supplementation. Endothelial function improved with both SPI and SP supplementation (p<0.01) with an increased reactive hyperemia index that was greater for the SPI group (p<0.05). Conclusions: Testosterone levels were unchanged and there was a significant improvement in glycaemia and cardiovascular risk markers with SPI compared to SP alone over three months. There was significant increase in TSH and a reduction in fT4

Functional replacement of myostatin with GDF-11 in the germline of mice.

BACKGROUND: Myostatin (MSTN) is a transforming growth factor-ß superfamily member that acts as a major regulator of skeletal muscle mass. GDF-11, which is highly related to MSTN, plays multiple roles during embryonic development, including regulating development of the axial skeleton, kidneys, nervous system, and pancreas. As MSTN and GDF-11 share a high degree of amino acid sequence identity, behave virtually identically in cell culture assays, and utilize similar regulatory and signaling components, a critical question is whether their distinct biological functions result from inherent differences in their abilities to interact with specific regulatory and signaling components or whether their distinct biological functions mainly reflect their differing temporal and spatial patterns of expression. METHODS: We generated and characterized mice in which we precisely replaced in the germline the portion of the Mstn gene encoding the mature C-terminal peptide with the corresponding region of Gdf11. RESULTS: In mice homozygous for the knock-in allele, all of the circulating MSTN protein was replaced with GDF-11, resulting in ~ 30-40-fold increased levels of circulating GDF-11. Male mice homozygous for the knock-in allele had slightly decreased muscle weights, slightly increased weight gain in response to a high-fat diet, slightly increased plasma cholesterol and HDL levels, and significantly decreased bone density and bone mass, whereas female mice were mostly unaffected. CONCLUSIONS: GDF-11 appears to be capable of nearly completely functionally replacing MSTN in the control of muscle mass. The developmental and physiological consequences of replacing MSTN with GDF-11 are strikingly limited

Lopinavir/Ritonavir Impairs Physical Strength in Association with Reduced Igf1 Expression in Skeletal Muscle of Older Mice

Background: Late-middle age HIV patients are prone to fatigue despite effective viral control by antiretroviral therapies. Rodent models to recapitulate this phenotype are still not available. Hypothesis Drug treatment may compromise muscle strength and physical performance more in older individuals with pre-existing metabolic disorders than normal young ones. Methods: Kaletra was given to overweight male mice at late-middle age and normal young adults; both on a rodent diet containing 30% fat calorie. Body composition and grip strength were measured at baseline and after drug treatment. Rota-rod running, insulin and glucose tolerance were measured at the end of the experiment. Drug effect on metabolic activity and spontaneous movements were assessed using the metabolic cage system. Representative muscle and fat tissue were analyzed for protein and mRNA expression. Selected findings were tested using murine C2C12 myotubes. Results: Kaletra reduced grip strength in both young and older mice but impaired rotarod performance only in the old. Spontaneous movements were also reduced in Kaletra-treated old mice. Kaletra reduced IGF-1 expression in all muscle groups tested for the old and in cultured myotubes but to a less extent in the muscle of young animals. Reduced IGF-1 expression correlated with increased expression of muscle-specific atrogene MAFbx and MuRF1. Kaletra also increased abdominal fat mass markedly in the old animals and to a less extend in the young. Conclusion: Long-term Kaletra intake aggravated abdominal obesity and impaired muscle strength. This effect was worse in older animals than in normal young adults

Supplementary Material: PREMATURE EXPRESSION OF AN AGE-ASSOCIATED MUSCLE SENESCENCE PATHWAY IN HIV INFECTION

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Identification of serum biomarkers for aging and anabolic response

<p>Abstract</p> <p>Objective</p> <p>With the progressive aging of the human population, there is an inexorable decline in muscle mass, strength and function. Anabolic supplementation with testosterone has been shown to effectively restore muscle mass in both young and elderly men. In this study, we were interested in identifying serum factors that change with age in two distinct age groups of healthy men, and whether these factors were affected by testosterone supplementation.</p> <p>Methods</p> <p>We measured the protein levels of a number of serum biomarkers using a combination of banked serum samples from older men (60 to 75 years) and younger men (ages 18 to 35), as well as new serum specimens obtained through collaboration. We compared baseline levels of all biomarkers between young and older men. In addition, we evaluated potential changes in these biomarker levels in association with testosterone dose (low dose defined as 125 mg per week or below compared to high dose defined as 300 mg per week or above) in our banked specimens.</p> <p>Results</p> <p>We identified nine serum biomarkers that differed between the young and older subjects. These age-associated biomarkers included: insulin-like growth factor (IGF1), N-terminal propeptide of type III collagen (PIIINP), monokine induced by gamma interferon (MIG), epithelial-derived neutrophil-activating peptide 78 (ENA78), interleukin 7 (IL-7), p40 subunit of interleukin 12 (IL-12p40), macrophage inflammatory protein 1β (MIP-1β), platelet derived growth factor β (PDGFβ) and interferon-inducible protein 10 (IP-10). We further observed testosterone dose-associated changes in some but not all age related markers: IGF1, PIIINP, leptin, MIG and ENA78. Gains in lean mass were confirmed by dual energy X-ray absorptiometry (DEXA).</p> <p>Conclusions</p> <p>Results from this study suggest that there are potential phenotypic biomarkers in serum that can be associated with healthy aging and that some but not all of these biomarkers reflect gains in muscle mass upon testosterone administration.</p

The mechanisms of androgen effects on body composition: mesenchymal pluripotent cell as the target of androgen action

Testosterone supplementation increases muscle mass primarily by inducing muscle fiber hypertrophy; however, the mechanisms by which testosterone exerts its anabolic effects on the muscle are poorly understood. The prevalent view is that testosterone improves net muscle protein balance by stimulating muscle protein synthesis, decreasing muscle protein degradation, and improving the reutilization of amino acids. However, the muscle protein synthesis hypothesis does not adequately explain testosterone-induced changes in fat mass, myonuclear number, and satellite cell number. We postulate that testosterone promotes the commitment of pluripotent stem cells into the myogenic lineage and inhibits their differentiation into the adipogenic lineage. The hypothesis that the primary site of androgen action is the pluripotent stem cell provides a unifying explanation for the observed reciprocal effects of testosterone on muscle and fat mass

Determinants of Serum Total and Free Testosterone Levels in Women over the Age of 65 Years

Context: Little is known about testosterone (T) levels and their determinants in women of late postmenopausal age. Objective: We describe levels of total and free T and selected factors that influence these levels in a random sample of older women. Design: Levels of serum total T and free T by microdialysis were measured using ultrasensitive assays in 347 community-dwelling women aged 65–98 yr enrolled in the Cardiovascular Health Study. Cross-sectional analyses were performed to define factors associated with total and free T levels. Results: In adjusted models: 1) total T levels declined with age until 80, whereas free T levels did not vary by age; 2) women with bilateral oophorectomy had 23% lower total T and 16% lower free T levels than those with at least one intact ovary; 3) oral estrogen users had total and free T levels that were 47% lower than never users; 4) obese women had 47% higher total T and 20% higher free T levels, and overweight women had 24% higher total T and 14% higher free T levels, than normal weight women; and 5) free T levels were 51% higher in black women. Corticosteroid users had 75% lower total T and 43% lower free T levels than nonusers. Conclusions: Bilateral oophorectomy, estrogen use, corticosteroid use, and low body mass index are independent risk factors for lower T levels in women aged 65 yr and over. Although highly prevalent in women of this age, the physiological significance of low T levels in late postmenopausal women requires further investigation

Self-administration Of Post-cycle Therapy Is Associated With Increased Probability Of Subsequent Normalisation Of Reproductive Hormones Following Anabolic-androgenic Steroid Cessation In Men

Context: Millions of men worldwide illicitly use anabolic-androgenic steroids (AAS) for muscle growth. However, AAS can cause death, cardiomyopathy, stroke, and psychosis. AAS use suppresses endogenous testosterone secretion for several months following cessation. Therefore, AAS cessation causes tiredness, low mood, insomnia, absent sexual function, and suicidality. There is currently no treatment recommended to reduce symptoms when men stop AAS. Some men empirically self-administer post-cycle therapy (PCT) drugs such as human chorionic gonadotrophin (hCG), selective oestrogen receptor modulators (SERM) and aromatase inhibitors (AI), aiming to restore endogenous testosterone. hCG directly stimulates endogenous testosterone production, while SERMs and AIs reduce the oestrogenic negative feedback on gonadotrophin secretion. Currently evidence is lacking to support the use of PCT in AAS-induced hypogonadism. Methods: Clinical audit from a single addiction service clinic, of 613 men stopping AAS in Scotland between 2015-2022. Men attended for a single, non-fasting, random blood test performed within 12 months of AAS cessation, with or without PCT use. Primary endpoint was the combination of reference range levels of serum LH, serum FSH and total testosterone, as a surrogate marker of biochemical recovery from hypogonadism. Results: PCT use was reported by 76% of men. Men using PCT had a significantly higher serum total testosterone following AAS cessation compared to men who did not (mean total testosterone nmol/L: 11.3 ± 6.7, no PCT; 12.8 ± 7.6, PCT; P=0.024). PCT use was associated with a higher probability (223/466, 48%, PCT; 56/147; 38%, no-PCT; P=0.04), and shorter time interval between stopping AAS and blood test of normalised reproductive hormones (13.3 ± 8.8 weeks, PCT;18.7 ± 12.0 weeks, no-PCT; P<0.01). The odds of biochemical normalisation during multivariable analysis were statistically significant when: (1) PCT was used (P=0.01); (2) fewer AAS were used (P=0.003); (3) shorter time of AAS use (P=0.02); (4) AAS used stopped for a longer time (P=0.03). Discussion: Our data provide primary evidence that self-administered PCT drugs may be associated with improved biochemical recovery from AAS-induced hypogonadism. These data require corroboration within an interventional study to determine causality. Nevertheless, these data may have important therapeutic implications for the future treatment of men who are motivated to stop AAS