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Muscle Content (muscle + content)
Kinds of Muscle Content Selected AbstractsTerritorial behaviour and immunity are mediated by juvenile hormone: the physiological basis of honest signalling?FUNCTIONAL ECOLOGY, Issue 1 2009Jorge Contreras-Garduño Summary 1The role of the juvenile hormone (JH) as a potential mediator in the trade-off between male,male competition and immune response has not been tested, but its study could reveal a potential mechanism that mediates resource allocation between these two traits. 2Controlling for body size, we tested whether males of the territorial damselfly Calopteryx virgo administrated with methoprene acid, an analog of the JH (JHa), compared to control males, increased their aggression and occupation time on territories but decreased their phenoloxidase (PO) activity (a key enzyme used during immune response after a bacterial challenge). We found an increase in aggression in JHa treated males compared to control males, but the opposite was found for PO activity. 3As fat load and muscle mass are also important traits during a contest, we tested whether JHa males compared to control males showed more fat and muscle content 2 h after JHa administration. Our results did not show a significant difference between both male groups, suggesting that JHa only increased aggression. 4These results and a review of other published articles, which have documented an effect of JH on a variety of functions in insects, suggest that JH may be a target of sexual selection: this hormone not only promotes the expression of secondary sexual characters but also seems condition-dependent and so its titers may indicate male condition. [source] Muscular design in the equine interosseus muscleJOURNAL OF MORPHOLOGY, Issue 6 2006Carl Soffler Abstract We studied the forelimb interosseus muscle in horses, Equus caballus, to determine the muscular properties inherent in its function. Some authors have speculated that the equine interosseus contains muscle fibers at birth only to undergo loss of these fibers through postnatal ontogeny. We describe the muscle fibers in eight interosseus specimens from adult horses. These fibers were studied histochemically using myosin ATPase studies and immunocytochemically using several antibodies directed against type I and type II myosin heavy chain antibodies. We determined that 95% of the fibers were type I, presumed slow-twitch fibers. All fibers exhibited normal morphological appearance in terms of fiber diameter and cross-sectional area, suggesting that the muscles are undergoing normal cycles of recruitment. SDS-PAGE studies of myosin heavy chain isoforms were consistent with these observations of primarily slow-twitch muscle. Fibers were determined to be ,800 ,m long when studied using nitric acid digestion protocols. Short fiber length combined with high pinnation angles suggest that the interosseus muscle is able to generate large amounts of force but can produce little work (measured as pulling the distal tendon proximally). While the equine interosseus muscle has undergone a general reduction of muscle content during its evolution, it remains composed of a significant muscular component that likely contributes to forelimb stability and elastic storage of energy during locomotion. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Striated muscle and nerve fascicle distribution in the female raturethral sphincterTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 2 2007Ronald J. Kim Abstract The anatomical basis for urinary continence depends on a thorough understanding of the tissues in the urethra. The objective of this study was to evaluate the morphology and neuroanatomy of urethral striated muscle, called the rhabdosphincter or external urethral sphincter, in normal female rats. Urethras from 12 female rats were dissected from the bladder, fixed, embedded in paraffin or epon, and sectioned every 1 mm. Striated muscle content was taken as the ratio of the striated muscle area to net urethral area. Nerve fascicles containing myelinated axons near the rhabdosphincter were counted and mapped. Both striated muscle content and number of nerve fascicles peak in the proximal third of the urethra, with a secondary peak at the distal end of the urethra. This secondary peak may correspond to an analog of the combined compressor urethrae/urethrovaginal sphincter located in the distal urethra in human. The rhabdosphincter has a variable distribution along the length of the urethra. In the middle and distal thirds of the urethra, the dorsal striated muscle fibers between the urethra and vagina become more sparse. The majority of nerve fascicles are contained in the lateral quadrants of the urethra, similar to the lateral distribution of somatic nerves in humans. In conclusion, this study demonstrates the normal distribution of the striated musculature and neuroanatomy in the urethra, with similarities to the human. It thus supports and extends the usefulness of the rat as an experimental model for studying urinary incontinence. Anat Rec 290:145,154, 2007. © 2007 Wiley-Liss, Inc. [source] The Effect of Intracavernous Injection of Adipose Tissue-Derived Stem Cells on Hyperlipidemia-Associated Erectile Dysfunction in a Rat ModelTHE JOURNAL OF SEXUAL MEDICINE, Issue 4pt1 2010Yun-Ching Huang MD ABSTRACT Introduction., Hyperlipidemia has been associated with erectile dysfunction (ED) via damage to the cavernous endothelium and nerves. Adipose tissue-derived stem cells (ADSC) have been shown to differentiate into endothelial cells and secrete vasculotrophic and neurotrophic factors. Aim., To assess whether ADSC have therapeutic effects on hyperlipidemia-associated ED. Methods., Twenty-eight male rats were induced to develop hyperlipidemia with a high-fat diet (hyperlipidemic rats, HR). Ten additional male rats were fed a normal diet to serve as controls (normal rats, NR). Five months later, all rats were subjected to ADSC isolation from paragonadal fat. The cells were cultured for 1 week, labeled with 5-ethynyl-2,-deoxyuridine (EdU), and then injected autologously into the corpus cavernosum of 18 HR. The remaining 10 HR rats were injected with phosphate buffered saline (PBS). At 2 and 14 days post-transplantation, four rats in the HR + ADSC group were sacrificed for tracking of the transplanted cells. At 28 days post-transplantation, all remaining rats were analyzed for serum biochemistry, erectile function, and penile histology. Main Outcome Measures., Erectile function was assessed by intracavernous pressure (ICP) measurement during electrostimulation of the cavernous nerve. Cavernous nerves, endothelium, and smooth muscle were assessed by immunohistochemistry. Results., Serum total cholesterol and low-density lipoprotein levels were significantly higher in HR than in NR. High-density lipoprotein level was significantly lower in HR than in NR. Mean ICP/mean arterial pressure ratio was significantly lower in HR + PBS than in NR + PBS or HR + ADSC. Neuronal nitric oxide synthase (nNOS)-positive nerve fibers and endothelial cells were fewer in HR + PBS than in HR + ADSC. Smooth muscle content was significantly higher in both HR groups than in NR. Conclusions., Hyperlipidemia is associated with abnormalities in both the nerves and endothelium. Treatment with ADSC ameliorates these adverse effects and holds promise as a potential new therapy for ED. Huang Y-C, Ning H, Shindel AW, Fandel TM, Lin G, Harraz AM, Lue TF, and Lin C-S. The effect of intracavernous injection of adipose tissue-derived stem cells on hyperlipidemia-associated erectile dysfunction in a rat model. J Sex Med 2010;7:1391,1400. [source] ORIGINAL RESEARCH,BASIC SCIENCE: Cavernous Neurotomy in the Rat is Associated with the Onset of an Overt Condition of HypogonadismTHE JOURNAL OF SEXUAL MEDICINE, Issue 5 2009Linda Vignozzi MD ABSTRACT Background., Most men following radical retropubic prostatectomy (RRP) are afflicted by erectile dysfunction (ED). RRP-related ED occurs as a result of surgically elicited neuropraxia, leading to histological changes in the penis, including collagenization of smooth muscle and endothelial damage. Aim., To verify whether hypogonadism could contribute to the pathogenesis of RRP-ED. Methods., Effects of testosterone (T), alone or in association with long-term tadalafil (Tad) treatment in a rat model of bilateral cavernous neurotomy (BCN). Main Outcome Measures., Penile tissues from rats were harvested for vasoreactivity studies 3 months post-BCN. Penile oxygenation was evaluated by hypoxyprobe immunostaining. Phosphodiesterase type 5 (PDE5), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) mRNA expression were quantified by Real Time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results., In BCN rats, we observed the onset of an overt condition of hypogonadism, characterized by reduced T plasma level, reduced ventral prostate weight, reduced testis function (including testis weight and number of Leydig cells), with an inadequate compensatory increase of luteinizing hormone. BCN induced massive penile hypoxia, decreased muscle/fiber ratio, nNOS, eNOS, PDE5 expression, increased sensitivity to the nitric oxide donor, sodium nitroprusside (SNP), and reduced the relaxant response to acetylcholine (Ach), as well as unresponsiveness to acute Tad dosing. In BCN rats, chronic Tad-administration normalizes penile oxygenation, smooth muscle loss, PDE5 expression, SNP sensitivity, and the responsiveness to the acute Tad administration. Chronic Tad treatment was ineffective in counteracting the reduction of nNOS and eNOS expression, along with Ach responsiveness. T supplementation, in combination with Tad, reverted some of the aforementioned alterations, restoring smooth muscle content, eNOS expression, as well as the relaxant response of penile strips to Ach, but not nNOS expression. Conclusion., BCN was associated with hypogonadism, probably of central origin. T supplementation in hypogonadal BCN rats ameliorates some aspects of BCN-induced ED, including collagenization of penile smooth muscle and endothelial dysfunction, except surgically induced altered nNOS expression.Vignozzi L, Filippi S, Morelli A, Marini M, Chavalmane A, Fibbi B, Silvestrini E, Mancina R, Carini M, Vannelli GB, Forti G, and Maggi M. Cavernous neurotomy in the rat is associated with the onset of an overt condition of hypogonadism. J Sex Med 2009;6:1270,1283. [source] ORIGINAL RESEARCH: Phosphodiesterase Type 5 Regulation in the Penile Corpora CavernosaTHE JOURNAL OF SEXUAL MEDICINE, Issue S3 2009Ching-Shwun Lin PhD ABSTRACT Introduction., Penile detumescence depends on the hydrolysis of cyclic guanosine monophosphate (cGMP) by phosphodiesterase type 5 (PDE5). It is hoped that a review of publications relevant to the regulation of PDE5 in the penis will be helpful to both scientists and clinicians who are interested in the sciences of erectile function/dysfunction. Aims., The aim of this article is to comprehensively review the mechanisms by which PDE5 activity and expression in the penis are regulated. All published studies relevant to PDE5 regulation in the penis or penile cells will be reviewed. Methods., Entrez (PubMed) was used to search for publications relevant to the topics of this review. Keywords used in the searches included vascular, cavernous, penis, smooth muscle, signaling molecules, erection, priapism, and PDE5. Articles that are dedicated to the study of erectile function/dysfunction were prioritized for citation. Results., Regulation of PDE5 can occur at both protein and gene levels. At protein level, PDE5 is activated by phosphorylation and/or allosteric cGMP binding. Deactivation is carried out by protein phosphatase 1 and thus linked to the Rho-kinase signaling pathway. Cleavage of PDE5 into an inactive form has been shown as carried out by caspase-3. At the gene level, PDE5 expression is regulated at two alternative promoters, PDE5A and PDE5A2, both of which are positively regulated by cyclic adenosine monophosphate and cGMP. Downregulation of PDE5 has been observed in the penis of castrated animals; however, proof of androgen regulation of PDE5 gene requires examination of the smooth muscle content. Hyperoxia and hypoxia, respectively, regulate PDE5 expression positively and negatively. Hypoxic downregulation of PDE5 is a possible mechanism for the development of priapism. Conclusions., PDE5 can be regulated at protein and gene levels. In the penis, changes of PDE5 activity have been linked to its phosphorylation status, and downregulation of PDE5 expression has been associated with hypoxia. Lin CS. PDE5 regulation in the penile corpora nervosa. J Sex Med 2009;6(suppl 3):203,209. [source] Effect of dietary administration of probiotics on growth and intestine functionality of juvenile Senegalese sole (Solea senegalensis, Kaup 1858)AQUACULTURE NUTRITION, Issue 2 2009M.A. SÁENZ de RODRIGÁÑEZ Abstract The effects of the dietary administration of two bacterial probiotic strains (Ppd11 and Pdp13) from the Alteromonadaceae family for 60 days, were assessed by measuring growth and feed efficiency, activities of leucine aminopeptidase and alkaline phosphatase and structural changes in the intestine of juvenile Senegalese sole. In addition, the profile of intestinal microbiota was studied by Denaturing Gradient Gel Electrophoresis. Growth and nutrient utilization were significantly higher in fish receiving probiotics than in those fed the control diet. No differences were observed in proximal composition between treatments, though higher lipid muscle content was measured in fish receiving Pdp13. Those fish also exhibited higher activities of AP when compared to Ppd11 and control groups. The profile of intestinal microbiota clearly separated those fish receiving probiotics from those of the control group. Microscopical examination revealed accumulation of lipid droplets in the enterocytes of fish receiving the control diet, but not in those fed on probiotics. Interactions between those structural changes and growth performance are discussed. [source] Differential effects of medroxyprogesterone acetate on thrombosis and atherosclerosis in miceBRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2009Till Freudenberger Background and purpose:, The risk for cardiovascular events including venous and arterial disease and stroke is elevated after treatment with estrogen and medroxyprogesterone acetate (MPA) in postmenopausal women. Here, we have investigated the effect of MPA on arterial thrombosis and atherosclerosis in a murine model of atherosclerosis. Experimental approach:, Apolipoprotein E (ApoE),/, mice were bilaterally ovariectomized and treated with placebo, MPA (27.7 µg·day,1) and MPA + 17-,-oestradiol (E2; 1.1 µg·day,1) for 90 days, on a Western-type diet. Thrombotic response was measured in a photothrombosis model, platelet activation by fluorescence activated cell sorting (FACS) analysis (CD62P) and thrombin generation by the endogenous thrombin potential (ETP). Furthermore, aortic plaque burden and aortic root plaque composition were determined. Key results:, MPA and MPA + E2 -treated animals showed an aggravated thrombotic response shown by significantly reduced time to stable occlusion. The pro-thrombotic effect of MPA was paralleled by increased ETP whereas platelet activation was not affected. Furthermore, MPA + E2 reduced the number of cells positive for ,-smooth muscle actin and increased hyaluronan in the plaque matrix. Interestingly, total plaque burden was reduced by MPA but unchanged by MPA + E2. Conclusion and implications:, Long-term treatment with MPA and MPA + E2 increased arterial thrombosis despite inhibitory effects of MPA on atherosclerosis in ApoE-deficient mice. Increased thrombin formation, reduced smooth muscle content and remodelling of non-collagenous plaque matrix may be involved in the pro-thrombotic effects. Thus, MPA exhibits differential effects on arterial thrombosis and on atherosclerosis. 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