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Modern tree sloths are one of few mammalian taxa for which quadrupedal suspension is obligatory. Sloth limb musculature is specialized for slow velocity, large force contractions that stabilize their body below branches and conserve energy during locomotion. However, it is unknown whether two- and three-toed sloths converge in their use of limb kinetics and if these patterns are comparable to how primates perform arboreal suspensory locomotion. This study addressed this need by collecting limb loading data in three-toed sloths (Bradypus variegatus; N=5) during suspensory walking. Sloths performed locomotor trials at their preferred speed on an instrumented beam apparatus with a force platform as the central supporting segment. Peak forces and impulses of the forelimb and hindlimb were recorded and analyzed in three dimensions. The hindlimbs of B. variegatus apply large braking forces greater in magnitude than peak forces generated by the forelimbs in propulsion, a pattern consistent with that observed in two-toed sloths. However, B. variegatus exhibits hindlimb-biased body weight support in vertical peak forces and impulse, with appreciable laterally directed forces in each limb pair, both of which vary from limb loading distributions in two-toed sloths. Moreover, body weight distribution between limb pairs is opposite to that employed by primates during quadrupedal suspension. Thus, there appear to be multiple strategies for achieving suspensory locomotion in arboreal mammals. These differences may be attributable to anatomical variation or phylogenetic position, but as of yet an explanation remains unknown. Future EMG analyses are expected to provide insight into how specific hindlimb muscle groups contribute to braking forces and stabilizing the center of mass of sloths during suspension.
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Perezosos , Animales , Perezosos/fisiología , Filogenia , Locomoción/fisiología , Miembro Posterior/fisiología , Primates/fisiología , Extremidad Inferior , Peso CorporalRESUMEN
Living sloths exhibit numerous anatomical specializations towards inverted quadrupedalism, however, previous studies have noted a more varied locomotor repertoire than previously anticipated. In this study, we present spatiotemporal gait characteristics and triaxial kinetic data from the brown-throated three-toed sloth (Bradypus variegatus) across three locomotor modes: terrestrial quadrupedal "crawling", suspensory walking, and vertical climbing. Compared to quadrupedal crawling and suspensory walking, B. variegatus adopted longer contact times and stride durations, larger duty factors, and greater speed during vertical climbing. Net fore-aft impulses were significantly greater during vertical climbing in both limb pairs than in quadrupedal crawling and suspensory walking. Functionally, during quadrupedal crawling and vertical climbing, both limb pairs served propulsive roles, while differentiation between a propulsive forelimb and braking hindlimb was observed during suspension. Net tangential forces differentiated vertical climbing kinetics from the other modes of locomotion, with the introduction of bidirectional pulling and pushing forces in the forelimb and hindlimb, respectively. The net mediolateral impulses were similar in vertical climbing and quadrupedal crawling as both limb pairs directed forces in one direction, whereas during suspensory walking, the laterally dominant forelimb was opposed by the medially dominant hindlimb. In total, this study provides novel data on the diverse locomotor dynamics in a slow-moving arboreal tetrapod and posits new testable hypotheses about the neuroplasticity and ease of transitioning between locomotor behaviors. The strikingly similar kinetic profiles of quadrupedal crawling and suspensory walking compared to vertical climbing suggest shared neuromuscular and mechanical demands between these mirrored locomotor modes.
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Perezosos , Xenarthra , Animales , Perezosos/fisiología , Locomoción/fisiología , Caminata/fisiología , Dedos del PieRESUMEN
For many animals, the juvenile stage of life can be particularly perilous. Once independent, immature animals must often complete the same basic survival functions as adults despite smaller body size and other growth-related limits on performance. Because, by definition, juveniles have yet to reproduce, we should expect strong selection for mechanisms to offset these ontogenetic limitations, allowing individuals to reach reproductive adulthood and maintain Darwinian fitness. We use an integrated ontogenetic dataset on morphology, locomotor performance, and longevity in wild cottontail rabbits (Sylvilagus floridanus, Allen 1848) to test the hypothesis that prey animals are under selective pressure to maximize juvenile performance. We predicted that (1) juveniles would accelerate more quickly than adults, allowing them to reach adult-like escape speeds, and (2) juveniles with greater levels of performance should survive for longer durations in the wild, thus increasing their reproductive potential. Using high-speed video and force platform measurements, we quantified burst acceleration, escape speed, and mechanical power production in 38 wild-caught S. floridanus (26 juveniles, 12 adults; all rabbits >1 kg in body mass were designated to be adults, based on published growth curves and evidence of epiphyseal fusion). A subsample of 22 rabbits (15 juveniles, 7 adults) was fitted with radio-telemetry collars for documenting survivorship in the wild. We found that acceleration and escape speed peaked in the late juvenile period in S. floridanus, at an age range that coincides with a period of pronounced demographic attrition in wild populations. Differences in mass-specific mechanical power production explained â¼75% of the variation in acceleration across the dataset, indicating that juvenile rabbits outpace adults by producing more power per unit body mass. We found a positive, though non-significant, association between peak escape speed and survivorship duration in the wild, suggesting a complex relationship between locomotor performance and fitness in growing S. floridanus.
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The material composition of vertebrate connective tissue is highly conserved across taxa. Existing data suggest that the compressive and tensile strength of limb bones are very similar despite marked variation in limb posture and locomotor patterns. However, the material properties of limb bone tissue from suspensory taxa have not been formally evaluated. Sloths are nearly obligatory in their use of below-branch suspensory locomotion and posture, thus placing their limb bones and associated soft tissue structures under routine tensile loading. It is possible that sloth limb bones are modified for enhanced tensile strength, perhaps at the expense of compressive strength. Forelimb and hindlimb bones of two-toed (Choloepus hoffmanni) and three-toed (Bradypus variegatus) sloths were tested in compression and bending to evaluate this hypothesis. Strength and elastic (Young's) modulus were similarly lower in sloth limb bones during both compression and bending, as compared with pronograde taxa. Ratios of peak bending strength to compressive strength additionally were elevated (sloths: 1.4-1.7; upright taxa: 0.6-1.2) for sloth limb bones. Overall, the material properties measured from the limb bones of tree sloths support our hypothesis of predicted function in a tensile limb system. Future studies should aim to directly test bones in tension to confirm indications of elevated axial tensile strength. Nevertheless, the results herein expand understanding of functional adaptation in mammalian tissue for a range of locomotor/postural behaviors that were previously unexplored.
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Perezosos , Animales , Extremidad Inferior , Postura , Resistencia a la Tracción , Extremidad SuperiorRESUMEN
Tree sloths rely on their limb flexors for bodyweight support and joint stability during suspensory locomotion and posture. This study aims to describe the myology of three-toed sloths and identify limb muscle traits that indicate modification for suspensorial habit. The pelvic limbs of the brown-throated three-toed sloth (Bradypus variegatus) were dissected, muscle belly mass was recorded, and the structural arrangements of the muscles were documented and compared with the available myological accounts for sloths. Overall, the limb musculature is simplified by containing muscles with generally long and parallel fascicles. A number of specific and informative muscle traits are additionally observed in the pelvic limb of B. variegatus: well-developed hip flexors and hip extensors each displaying several fused bellies; massive knee flexors; two heads of the m. adductor longus and m. gracilis; robust digital flexors and flexor tendons; m. tibialis cranialis muscle complex originating from the tibia and fibula and containing a modified m. extensor digitorum I longus; appreciable muscle mass devoted to ankle flexion and hindfoot supination; only m. extensor digitorum brevis acts to extend the digits. Collectively, the findings for tree sloths emphasize muscle mass and organization for suspensory support namely by the hip flexors, knee flexors, and limb adductors, for which the latter two groups may stabilize suspensory postures by exerting appreciable medially-directed force on the substrate. Specializations in the distal limb are also apparent for sustained purchase of the substrate by forceful digital flexion coupled with strong ankle flexion and supination of the hind feet, which is permitted by the reorganization of several digital extensors. Moreover, the reduction or loss of other digital flexor and ab-adductor muscles marks a dramatic simplification of the intrinsic foot musculature in B. variegatus, the extent to which varies across extant species of two- and three-toed tree sloths and likely is related to substrate preference/use.
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Perezosos , Animales , Miembro Posterior/fisiología , Locomoción/fisiología , Músculo Esquelético , Postura , Perezosos/fisiologíaRESUMEN
Descriptions of myology reflect adaptations of the post-cranium and are essential for understanding the functional morphology of animal limbs. Armadillos (Cingulata) are the most species-rich group of the basal superorder Xenarthra, which is evident by their various lifestyles (subterranean vs. terrestrial) and levels of fossoriality (fossorial vs. semi-fossorial). While there have been several studies on limb bone proportions in numerous armadillos, limb myology has been reported for a limited number of species. Many of these descriptions need updating, and detailed quantitative muscle data are available only for nine-banded armadillos. The main objective of this study is to assess the forelimb myology of the pichi (Zaedyus pichiy), screaming hairy (Chaetophractus vellerosus), large hairy (Chaetophractus villosus), and pink fairy (Chlamyphorus truncatus) armadillos with comparisons to previous observations to specify muscle traits that indicate scratch-digging specializations in cingulates. Several myological features are variable among the species studied, including the origin of m. trapezius pars cervicalis, presence of a distinct m. rhomboideus profundus and m. omotransversarius, and number of heads present for m. triceps brachii and m. flexor digitorum profundus, all of which can be associated with variability in their respective habitats and functional habits. These traits are consistently observed in the members of the Euphractinae, whereas they are slightly divergent (i.e., reduced complexity) in the pink fairy armadillo despite a similar distribution of muscle mass in the limb retractors, elbow extensors, and carpal/digital flexors across species. The ecomorphology observed here among cingulates also confirms their recent reorganization into separate families and subfamilies.
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Armadillos/anatomía & histología , Miembro Anterior/anatomía & histología , Músculo Esquelético/anatomía & histología , Adaptación Biológica , Animales , Armadillos/fisiología , Miembro Anterior/fisiología , Músculo Esquelético/fisiologíaRESUMEN
Sloths exhibit almost obligatory suspensory locomotion and posture. These behaviors require both strength and fatigue resistance, although we previously found muscle fiber type characteristics in the forelimbs of sloths that belied these initial expectations. Based on locomotor roles of the forelimbs versus hindlimbs in propulsion and braking, respectively, sloth hindlimb musculature should be adapted for force production and energy savings by a near homogeneous expression of slow myosin heavy chain (MHC) fibers. This hypothesis was tested by determining MHC fiber type (%) distribution and energy metabolism in the hindlimbs of three-toed (B. variegatus, N = 5) and two-toed (C. hoffmanni, N = 3) sloths. A primary expression of the slow MHC-1 isoform was found in the hindlimbs of both species. Slow MHC fiber type (%) was significantly greater in the flexors of B. variegatus, whereas expression of fast MHC-2A fibers was significantly greater in the extensors of C. hoffmannni. MHC-1 fibers were largest in cross-sectional area (CSA) and comprised the greatest %CSA in each muscle sampled from both species. Enzyme assays showed elevated activity for anaerobic enzymes (CK and LDH) compared with low-to-moderate activity for aerobic enzymes (3-HAD and CS), and only CK activity was related to body size. These findings emphasize a joint stabilization role by the hindlimbs during suspension, especially in smaller three-toed sloths, and suggest that larger two-toed sloths could have muscles further modified for greater power output and/or prolonged arboreal maneuvering. Moreover, modifications to muscle metabolism rather than MHC expression may be more reflective of functional adaptation in sloth limbs.
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Perezosos , Animales , Miembro Anterior , Miembro Posterior , Músculos , Cadenas Pesadas de MiosinaRESUMEN
Sloths exhibit below branch locomotion whereby their limbs are loaded in tension to support the body weight. Suspensory behaviors require both strength and fatigue resistance from the limb flexors; however, skeletal muscle mass of sloths is reduced compared with other arboreal mammals. Although suspensory locomotion demands that muscles are active to counteract the pull of gravity, it is possible that sloths minimize muscle activation and/or selectively recruit slow motor units to maintain support, thus indicating neuromuscular specializations to conserve energy. Electromyography (EMG) was evaluated in a sample of three-toed sloths (Bradypus variegatus; N=6) to test this hypothesis. EMG was recorded at 2000â Hz via fine-wire electrodes implanted into two suites of four muscles in the left forelimb while sloths performed suspensory hanging (SH), suspensory walking (SW) and vertical climbing (VC). All muscles were minimally active for SH. During SW and VC, sloths moved slowly (duty factor: 0.83) and activation patterns were consistent between behaviors; the flexors were activated early and for a large percentage of limb contact, whereas the extensors were activated for shorter burst durations on average and showed biphasic (contact and swing) activity. Muscle activities were maximal for the elbow flexors and lowest for the carpal/digital flexors, and overall activity was significantly greater for SW and VC compared with SH. Wavelet analysis indicated high mean EMG frequencies from the myoelectric intensity spectra coupled with low burst intensities for SH, although the opposite pattern occurred for SW and VC, with the shoulder flexors and elbow flexor, m. brachioradialis, having extremely low mean EMG frequencies that are consistent with recruitment of slow fibers. Collectively, these findings support the hypothesis and suggest that sloths may selectively recruit smaller, fast motor units for suspensory postures but have the ability to offset the cost of force production by recruitment of large, slow motor units during locomotion.
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Electromiografía , Locomoción , Perezosos , Animales , Miembro Anterior , Músculo EsqueléticoRESUMEN
RESEARCH QUESTIONS: Can a previously defined relationship between sperm capacitation and the probability of a man generating pregnancy within three cycles, prospectively predict male fertility in diverse clinical settings? A second study asked, what is the prevalence of impaired sperm fertilizing ability in men questioning their fertility (MQF), and does this relate to traditional semen analysis metrics? DESIGN: In the multicentric, prospective observational study, data (n = 128; six clinics) were analysed to test a published relationship between the percentage of fertilization-competent, capacitated spermatozoa (Cap-Score) and probability of generating pregnancy (PGP) within three cycles of intrauterine insemination. Logistic regression of total pregnancy outcomes (n = 252) assessed fit. In the cohort comparison, Cap-Scores of MQF (n = 2155; 22 clinics) were compared with those of 76 fertile men. RESULTS: New outcomes (n = 128) were rank-ordered by Cap-Score and divided into quintiles (25-26 per group); chi-squared testing revealed no difference between predicted and observed pregnancies (P = 0.809). Total outcomes (n = 252; 128 new + 124 previous) were pooled and the model recalculated, yielding an improved fit (P < 0.001). Applying the Akaike information criterion found that the optimal model used Cap-Score alone. Cap-Scores were performed on 2155 men (with semen analysis data available for 1948). To compare fertilizing ability, men were binned by PGP (≤19%, 20-29%, 30-39%, 40-49%, 50-59%, ≥60%). Distributions of PGP and the corresponding Cap-Scores were significantly lower in MQF versus fertile men (P < 0.001). Notably, 64% of MQF with normal volume, concentration and motility (757/1183) had PGP of 39% or less (Cap-Scores ≤31), versus 25% of fertile men. CONCLUSIONS: Sperm capacitation prospectively predicted male fertility. Impaired capacitation affects many MQF with normal semen analysis results, informing diagnosis versus idiopathic infertility.
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Fertilidad/fisiología , Fertilización/fisiología , Infertilidad Masculina/fisiopatología , Capacitación Espermática/fisiología , Espermatozoides/fisiología , Femenino , Humanos , Masculino , Embarazo , Índice de Embarazo , Estudios Prospectivos , Análisis de Semen , Motilidad Espermática/fisiologíaRESUMEN
INTRODUCTION: Premature ejaculation (PE) is among the most common sexual dysfunctions that affect men. Currently, topical medications are considered a first-line treatment option for PE, with no specific medication having market approval in the United States specifically for the treatment of PE. Topical agents for PE include eutectic mixture of local anesthetics cream, topical eutectic mixture for premature ejaculation spray, severance secret-cream, resiniferatoxin, and an assortment of over-the-counter treatments, including medicated condoms, sprays, and wipes. AIM: Given the paucity of controlled studies for these treatment modalities, the goal of this article is to review the currently available options for PE to help educate providers in appropriate treatment options. METHODS: Comprehensive review of published literature, as well as clinical experience were evaluated to determine efficacy of known treatments for PE. MAIN OUTCOME MEASURE: The topical treatment options and efficacy of these options for PE were reviewed. Eutectic mixture of local anesthetics, topical eutectic mixture for premature ejaculation, severance secret-cream, resiniferatoxin, and medicated condoms are the mainstay of treatment. Each has certain risks and benefits associated with use as described, as well as relative cost of use. RESULTS: Although data supporting the effectiveness of topical agents for PE is limited, prior clinical trials demonstrate increases in timed intravaginal ejaculatory latency time and improved patient-partner sexual satisfaction survey scores on some treatment options. CONCLUSION: More research is needed to evaluate efficacy, cost-effectiveness, potential side effects, and benefits of combined medical and psychological intervention for better ejaculatory control. Butcher MJ, Zubert T, Christiansen K, et al. Topical Agents for Premature Ejaculation: A Review. Sex Med Rev 2020;8:92-99.
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Anestésicos Locales/uso terapéutico , Eyaculación Prematura/tratamiento farmacológico , Condones , Diterpenos/uso terapéutico , Humanos , Masculino , Eyaculación Prematura/fisiopatologíaRESUMEN
Comparative analyses of locomotion in tetrapods reveal two patterns of stride cycle variability. Tachymetabolic tetrapods (birds and mammals) have lower inter-cycle variation in stride duration than bradymetabolic tetrapods (amphibians, lizards, turtles and crocodilians). This pattern has been linked to the fact that birds and mammals share enlarged cerebella, relatively enlarged and heavily myelinated Ia afferents, and γ-motoneurons to their muscle spindles. Both tachymetabolic tetrapod lineages also possess an encapsulated Golgi tendon morphology, thought to provide more spatially precise information on muscle tension. The functional consequence of this derived Golgi tendon morphology has never been tested. We hypothesized that one advantage of precise information on muscle tension would be lower and more predictable limb bone stresses, achieved in tachymetabolic tetrapods by having less variable substrate reaction forces than bradymetabolic tetrapods. To test this hypothesis, we analyzed hindlimb substrate reaction forces during locomotion of 55 tetrapod species in a phylogenetic comparative framework. Variation in species means of limb loading magnitude and timing confirm that, for most of the variables analyzed, variance in hindlimb loading and timing is significantly lower in species with encapsulated versus unencapsulated Golgi tendon organs. These findings suggest that maintaining predictable limb loading provides a selective advantage for birds and mammals by allowing energy savings during locomotion, lower limb bone safety factors and quicker recovery from perturbations. The importance of variation in other biomechanical variables in explaining these patterns, such as posture, effective mechanical advantage and center-of-mass mechanics, remains to be clarified.
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Anfibios/fisiología , Aves/fisiología , Miembro Posterior/fisiología , Mamíferos/fisiología , Reptiles/fisiología , Animales , Fenómenos Biomecánicos , Estrés MecánicoRESUMEN
Juvenile animals must survive in the same environment as adults despite smaller sizes, immature musculoskeletal tissues, general ecological naïveté and other limits of performance. Developmental changes in muscle leverage could constitute one mechanism to promote increased performance in juveniles despite ontogenetic limitations. We tested this hypothesis using a holistic dataset on growth and locomotor development in wild eastern cottontail rabbits (Sylvilagus floridanus) to examine ontogenetic changes in hindlimb muscle effective mechanical advantage (EMA). EMA is a dimensionless index of muscle leverage, equal to the quotient of average muscle lever length and the load arm length of the ground reaction force (GRF), effectively representing the magnitude of output force arising from a given muscle force. We found that EMA at the hip and ankle joints, as well as overall hindlimb EMA, significantly declined across ontogeny in S. floridanus, whereas EMA at the knee joint remained unchanged. Ontogenetic decreases in EMA were due to isometric scaling of muscle lever arm lengths alongside positive ontogenetic allometry of GRF load arm lengths - which in turn was primarily related to positive allometry of hindlimb segment lengths. Greater EMA limits the estimated volume of hindlimb extensor muscle that has to be activated in young rabbits, likely mitigating the energetic cost of locomotion and saving metabolic resources for other physiological functions, such as growth and tissue differentiation. An additional examination of limb growth allometry across a diverse sample of mammalian taxa suggests that ontogenetic decreases in limb joint EMA may be a common mammalian trend.
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Lagomorpha/fisiología , Locomoción , Animales , Fenómenos Biomecánicos , Lagomorpha/crecimiento & desarrolloRESUMEN
The Himalayan marmot (Marmota himalayana) is a hibernating mammal that inhabits the high-elevation regions of the Himalayan mountains. Here we present a draft genome of the Himalayan marmot, with a total assembly length of 2.47 Gb. Phylogenetic analyses showed that the Himalayan marmot diverged from the Mongolian marmot approximately 1.98 million years ago. Transcriptional changes during hibernation included genes responsible for fatty acid metabolism in liver and genes involved in complement and coagulation cascades and stem cell pluripotency pathways in brain. Two selective sweep genes, Slc25a14 and ψAamp, showed apparent genotyping differences between low- and high-altitude populations. As a processed pseudogene, ψAamp may be biologically active to influence the stability of Aamp through competitive microRNA binding. These findings shed light on the molecular and genetic basis underlying adaptation to extreme environments in the Himalayan marmot.
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OBJECTIVE: To quantify reports made to the Food and Drug Administration Adverse Event Reporting System (FAERS), create a demographic of patient reports, and examine the cluster of symptoms to correlate consistency of postfinasteride syndrome (PFS) complaints. PFS is a provisional diagnosis encompassing a cluster of sexual, physical, and psychological and/or neurologic symptoms associated with 5-alpha reductase inhibitor use that emerge or continue after discontinuation of medication. MATERIALS AND METHODS: FAERS dataset of 5-alpha reductase inhibitors from April 2011 to October 2014 was obtained. Each FAERS report had 16 categories for completion, but not every report was fully completed. Statistical analysis compared variables of interest between the 2 doses of finasteride (1 mg vs 5 mg). RESULTS: From FAERS, 2048 monotherapy cases were identified: 1581 of finasteride 1 mg, 240 of finasteride 5 mg, and 226 of unreported doses. Possibly related to labeling changes, from 2011 to 2014, there was a significant increase in adverse events (AEs) reported involving 1 mg dosing. Finasteride use was reported with many sexual AEs including diminished libido, erectile dysfunction, and ejaculatory complaints. Other common AEs included dermatologic, metabolic, and psychological and/or neurologic complaints. There were more AE reports with the 1 mg dose than the 5 mg dose. One case of dutasteride reported back pain, not generally attributed to PFS. CONCLUSION: FAERS data suggests that finasteride exposure is reported with a diverse collection of symptoms, particularly in younger men on 1 mg dosage compared to older men on 5 mg. Many of these complaints fall well out of the realm of previously established AEs from long-term controlled studies.
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Inhibidores de 5-alfa-Reductasa/efectos adversos , Sistemas de Registro de Reacción Adversa a Medicamentos , Finasterida/efectos adversos , Inhibidores de 5-alfa-Reductasa/administración & dosificación , Adulto , Factores de Edad , Conjuntos de Datos como Asunto , Relación Dosis-Respuesta a Droga , Erupciones por Medicamentos/epidemiología , Fatiga/inducido químicamente , Fatiga/epidemiología , Finasterida/administración & dosificación , Ginecomastia/inducido químicamente , Ginecomastia/epidemiología , Trastornos de la Audición/inducido químicamente , Trastornos de la Audición/epidemiología , Humanos , Libido/efectos de los fármacos , Masculino , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/epidemiología , Persona de Mediana Edad , Debilidad Muscular/inducido químicamente , Debilidad Muscular/epidemiología , Prostatitis/inducido químicamente , Prostatitis/epidemiología , Disfunciones Sexuales Fisiológicas/inducido químicamente , Disfunciones Sexuales Fisiológicas/epidemiología , Trastornos del Sueño-Vigilia/inducido químicamente , Trastornos del Sueño-Vigilia/epidemiología , Estados Unidos/epidemiología , United States Food and Drug AdministrationRESUMEN
Sloths are canopy-dwelling inhabitants of American neotropical rainforests that exhibit suspensory behaviors. These abilities require both strength and muscular endurance to hang for extended periods of time; however, the skeletal muscle mass of sloths is reduced, thus requiring modifications to muscle architecture and leverage for large joint torque. We hypothesize that intrinsic muscle properties are also modified for fatigue resistance and predict a heterogeneous expression of slow/fast myosin heavy chain (MHC) fibers that utilize oxidative metabolic pathways for economic force production. MHC fiber type distribution and energy metabolism in the forelimb muscles of three-toed ( Bradypus variegatus, n = 5) and two-toed ( Choloepus hoffmanni, n = 4) sloths were evaluated using SDS-PAGE, immunohistochemistry, and enzyme activity assays. The results partially support our hypothesis by a primary expression of the slow MHC-1 isoform as well as moderate expression of fast MHC-2A fibers, whereas few hybrid MHC-1/2A fibers were found in both species. MHC-1 fibers were larger in cross-sectional area (CSA) than MHC-2A fibers and comprised the greatest percentage of CSA in each muscle sampled. Enzyme assays showed elevated activity for the anaerobic enzymes creatine kinase and lactate dehydrogenase compared with low activity for aerobic markers citrate synthase and 3-hydroxyacetyl CoA dehydrogenase. These findings suggest that sloth forelimb muscles may rely heavily on rapid ATP resynthesis pathways, and lactate accumulation may be beneficial. The intrinsic properties observed match well with suspensory requirements, and these modifications may have further evolved in unison with low metabolism and slow movement patterns as means to systemically conserve energy. NEW & NOTEWORTHY Myosin heavy chain (MHC) fiber type and fiber metabolic properties were evaluated to understand the ability of sloths to remain suspended for extended periods without muscle fatigue. Broad distributions of large, slow MHC-1 fibers as well as small, fast MHC-2A fibers are expressed in sloth forelimbs, but muscle metabolism is generally not correlated with myosin fiber type or body size. Sloth muscles rely on rapid, anaerobic pathways to resist fatigue and sustain force production.
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Miembro Anterior/fisiología , Fibras Musculares Esqueléticas/fisiología , Cadenas Pesadas de Miosina/metabolismo , Perezosos/fisiología , Envejecimiento/fisiología , Animales , Citrato (si)-Sintasa/metabolismo , Creatina Quinasa/metabolismo , Metabolismo Energético/fisiología , Femenino , Miembro Anterior/enzimología , Miembro Anterior/crecimiento & desarrollo , L-Lactato Deshidrogenasa/metabolismo , Masculino , Fatiga Muscular/fisiología , Fibras Musculares Esqueléticas/enzimología , Fibras Musculares Esqueléticas/ultraestructura , Cadenas Pesadas de Miosina/biosíntesisRESUMEN
BACKGROUND: After radical prostatectomy (RP), erectile dysfunction, often necessitating the need for inflatable penile prosthesis (IPP) insertion, and urinary incontinence and climacturia can ensue. AIM: To assess the efficacy and safety of the mini-jupette, a mesh used to approximate the medial aspects of the 2 corporotomies at the time of IPP insertion, for the management of climacturia and urine leakage in patients with minimal incontinence. METHODS: We conducted a pilot multicenter study of patients with post-RP erectile dysfunction and climacturia and/or mild urinary incontinence (≤2 pads/day [ppd]) undergoing IPP insertion with concomitant placement of a mini-jupette graft. OUTCOMES: Pre- and postoperative erectile function, continence and climacturia, and overall surgical outcomes were assessed. RESULTS: 38 patients underwent the mini-jupette procedure. The mean age of the population was 65.3 years (SD = 7.7). 30 had post-RP climacturia and 32 patients had post-RP incontinence (mean = 1.3 ppd, SD = 0.8). 31 patients received Coloplast Titan, 4 received AMS 700 LGX, and 3 received AMS 700 CX IPPs. Mean corporotomy size was 2.9 cm (SD = 1.0). Mean graft measurements were 3.2 cm (SD = 0.9) for width, 3.3 cm (SD = 1.3) for length, and 11.0 cm2 (SD = 5.1) for surface area. At a mean follow-up of 5.1 months (SD = 6.9), there were 5 postoperative complications (13.2%) of which 4 required explantation. Climacturia and incontinence were subjectively improved in 92.8% and 85.7%, respectively. Mean ppd decreased by 1.3 postoperatively. CLINICAL IMPLICATIONS: The Andrianne mini-jupette is a feasible adjunct to IPP placement that can be used for subsets of patients with post-RP climacturia and/or minimal incontinence. STRENGTHS AND LIMITATIONS: Strengths of this study include the novel nature of this intervention, the multi-institutional nature of the study, and the promising results demonstrated. Limitations include the retrospective nature of the study and the heterogeneity of the techniques and grafts used by different surgeons involved. CONCLUSION: Longer follow-up and larger patient cohorts are needed to confirm the long-term safety and benefits of this intervention. Yafi FA, Andrianne R, Alzweri L, et al. Andrianne Mini-Jupette Graft at the Time of Inflatable Penile Prosthesis Placement for the Management of Post-Prostatectomy Climacturia and Minimal Urinary Incontinence. J Sex Med 2018;15:789-796.
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Disfunción Eréctil/etiología , Disfunción Eréctil/cirugía , Implantación de Pene/métodos , Prostatectomía/efectos adversos , Incontinencia Urinaria/etiología , Anciano , Humanos , Masculino , Persona de Mediana Edad , Prótesis de Pene , Proyectos Piloto , Periodo Posoperatorio , Estudios RetrospectivosRESUMEN
Terrestrial opossums use their semiprehensile tail for grasping nesting materials as opposed to arboreal maneuvering. We relate the development of this adaptive behavior with ontogenetic changes in myosin heavy chain (MHC) isoform expression from 21 days to adulthood. Monodelphis domestica is expected to demonstrate a progressive ability to flex the distal tail up to age 7 mo, when it should exhibit routine nest construction. We hypothesize that juvenile stages (3-7 mo) will be characterized by retention of the neonatal isoform (MHC-Neo), along with predominant expression of fast MHC-2X and -2B, which will transition into greater MHC-1ß and -2A isoform content as development progresses. This hypothesis was tested using Q-PCR to quantify and compare gene expression of each isoform with its protein content determined by gel electrophoresis and densitometry. These data were correlated with nesting activity in an age-matched sample of each age group studied. Shifts in regulation of MHC gene transcripts matched well with isoform expression. Notably, mRNA for MHC-Neo and -2B decrease, resulting in little-to-no isoform translation after age 7 mo, whereas mRNA for MHC-1ß and -2A increase, and this corresponds with subtle increases in content for these isoforms into late adulthood. Despite the tail remaining intrinsically fast-contracting, a critical growth period for isoform transition is observed between 7 and 13 mo, correlating primarily with use of the tail during nesting activities. Functional transitions in MHC isoforms and fiber type properties may be associated with muscle "tuning" repetitive nest remodeling tasks requiring sustained contractions of the caudal flexors.NEW & NOTEWORTHY Little is understood about skeletal muscle development as it pertains to tail prehensility in mammals. This study uses an integrative approach of relating both MHC gene and protein expression with behavioral and morphometric changes to reveal a predominant fast MHC expression with subtle isoform transitions in caudal muscle across ontogeny. The functional shifts observed are most notably correlated with increased tail grasping for nesting activities.
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Fuerza de la Mano/fisiología , Monodelphis/fisiología , Cadenas Pesadas de Miosina/biosíntesis , Cadenas Pesadas de Miosina/genética , Cola (estructura animal)/fisiología , Animales , Femenino , Expresión Génica , Masculino , Miosinas/biosíntesis , Miosinas/genética , Isoformas de Proteínas/biosíntesis , Isoformas de Proteínas/genéticaRESUMEN
INTRODUCTION: Delayed ejaculation (DE) is a poorly defined disorder that entails the delay or absence of orgasm that results in personal distress. Numerous causes of DE exist, and management must be tailored to the specific etiology to maximize treatment success. Management strategies include psychological and sexual therapy, pharmacotherapy, and penile vibratory stimulation. AIM: This article intends to review the pathophysiology and treatment options for DE discussed in the literature to date. METHODS: A review of the literature was performed to identify and evaluate the existing data on treatment success for the various forms of DE management. MAIN OUTCOME MEASURES: Each treatment option was evaluated for method of administration, data supporting its success for DE, and potential risks or side effects. RESULTS: Different psychosexual therapy strategies have been described for DE but with limited data to describe efficacy. There is no medication for DE approved by the United States Food and Drug Administration. The quality of evidence supporting the off-label use of medications for DE is low. However, there are numerous medications reported in the literature suggested to treat the condition. Cabergoline and bupropion are the two most commonly used. In addition, penile vibratory stimulation has been described as an adjunct treatment option for DE. CONCLUSION: There are different treatment options reported for DE, all with limited evidence supporting their efficacy. Identifying the etiology of the DE is important to appropriately target therapy. A multimodal approach combining psychosexual therapy with medications and/or penile vibratory stimulation will likely provide the best outcomes.
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Eyaculación/fisiología , Disfunciones Sexuales Fisiológicas , Disfunciones Sexuales Psicológicas , Humanos , Masculino , Orgasmo , Pene , Psicoterapia/métodos , Conducta Sexual , Resultado del TratamientoRESUMEN
OBJECTIVE: To test the hypothesis that morphology is the best predictor of clinical pregnancy (CP) when employing intrauterine insemination (IUI). STUDY DESIGN: We retrospectively reviewed a registry of 527 couples who collectively underwent 1,027 IUI cycles, testing sperm parameters and other variables with univariate and multivariate analyses for association with CP. With the literature scant regarding the impact of sperm morphology on IUI outcome, we determined semen parameter threshold values in our patient population and compared them to published reference range values. A logistic regression model was used to determine predictors of CP. RESULTS: Fecundity was 12.9% per cycle and fertility was 23.3% by the third attempted cycle. Morphology was the most significant parameter predicting CP with IUI. Motility was also significant when employing our new threshold values. Using receiver operator characteristic curve analysis, values 16% morphology and 69% motility were found to be the optimal threshold values for achieving CP. CONCLUSION: Morphology was the best predictor of CP. When considering IUI, the best chance of clinical pregnancy occurs when both motility and morphology values are above normal thresholds.