Anatomy of Cowper's gland in humans suggesting a secretion and emission mechanism facilitated by cooperation of striated and smooth muscles.

This study presents the detailed anatomy of the Cowper's gland in humans. Elucidating the mechanism of secretion and emission of the Cowper's gland requires analysis of the muscles around the Cowper's gland. We hypothesized that the Cowper's gland involves not only smooth muscle but also the striated muscles of the pelvic floor. Here, we provide comprehensive and three-dimensional anatomy of the Cowper's gland and its surrounding structures, which overcomes the current local and planar understanding. In this study, seven male corpses of body donors were used to conduct macroscopic anatomy, histology, and three-dimensional reconstruction. The Cowper's gland was surrounded laterally and posterosuperiorly by striated and smooth muscles, respectively. The striated muscle bundle was connected from the superficial transverse perineal muscle, levator ani, and external anal sphincter to the external urethral sphincter (rhabdosphincter). The smooth muscle was part of the deep transverse perineal muscle and entered between the bilateral Cowper's glands and lobules. Our findings indicate that the secretion and emission of the Cowper's gland in humans are carried out through the cooperation of striated and smooth muscles.

Mind the Gap: Changes in Levator Dimensions After Sacrocolpopexy.

OBJECTIVE: The aim of the study was to compare levator hiatus (LH) and levator area (LA) on transvaginal 3-dimensional (3D) ultrasound (US) and genital hiatus (GH) size by Pelvic Organ Prolapse Quantification (POP-Q) examination before and after minimally invasive sacrocolpopexy. METHODS: Women with prolapse (POP) beyond the hymen undergoing minimally invasive sacrocolpopexy without concomitant POP repairs completed Pelvic Floor Distress Inventory short form (PFDI), POP-Q, and transvaginal 3D US before and 14 weeks after surgery. Data were analyzed by 2 urogynecologists, blinded to US image sequence and to corresponding POP-Q scores. RESULTS: Forty-three patients were enrolled; 35 with complete data are included. Patients had a mean ± SD age of 55 ± 11 years. Most were white (89%), vaginally parous (94%), postmenopausal (66%), sexually active (63%), and had stage 3 POP (86%). The majority (89%) had concomitant hysterectomy, and 60% had midurethral slings. At baseline, the mean ± SD PFDI and Prolapse subscale of the Pelvic Floor Distress Inventory scores were 98 ± 50 and 42 ± 22. The median (interquartile range) POP-Q stage decreased after surgery from 3 (3) to 0 (0-1, P < 0.001) and the mean ± SD PFDI scores decreased to 55 ± 42 (P = 0.002). At baseline, the mean ± SD GH and perineal body measurements were 3.5 ± 0.7 and 2.4 ± 0.6 cm. Although the GH size decreased by 0.5 cm after surgery, perineal body was unchanged. Levator hiatus remained unchanged between the baseline and 14-week visits (P = 0.07), whereas LA increased by 0.8 cm2 (P = 0.03). At 14 weeks, the change in LA was not correlated with the change in GH (ρ = -0.2, P = 0.2) or POP stage (ρ = -0.2, P = 0.9). CONCLUSIONS: Restoring the apex with sacrocolpopexy alone reduces GH size on clinical examination; however, it does not impact the size of the underlying LH on US.

Organization of Buccal Cone Musculature in the Pteropod Mollusc Clione limacina.

The pteropod mollusc Clione limacina is a feeding specialist, preying on shelled pteropods of the genus Limacina. Specialized prey-capture structures, called buccal cones, are hydraulically everted from within the mouth to capture the prey. Once captured, the prey is manipulated so the shell opening is over the mouth of Clione. Analyses of high-speed cine sequences of prey capture suggest that the mouth is actively opened rather than passively forced open by buccal cone eversion. The inflated buccal cones are initially straight and form a wide angle (maximum, 113°) prior to prey contact. Individual buccal cones bend orally following prey contact, suggesting a sensory trigger. To determine the muscular basis of buccal cone movements, the musculature of the buccal cones is described. Three distinct muscle fiber types include circular smooth muscle, longitudinal smooth muscle, and longitudinal striated muscle. The organization, distribution, and innervation of the muscle types suggest that circular muscle is used during buccal cone eversion, longitudinal smooth muscle is used for buccal cone withdrawal, and longitudinal striated muscle is used for oral bending of the buccal cones after prey contact and for manipulation of the prey.

Regional variations in the number distribution of intrinsic myenteric neurons and coinnervated motor endplates on the striated muscles in the rat esophagus.

The roles of intrinsic neurons and the significance of the coinnervated striated muscles in the esophagus are unclear. We examined the number distribution of intrinsic neurons and coinnervated motor endplates on the striated muscles in the rat esophagus using immunohistochemistry to investigate whether these neurons and coinnervated striated muscles may be relevant to the local control of esophageal motility. The number of PGP9.5-positive neurons was higher in the cervical esophagus (segment 1) and gradually decreased toward the aboral, with a moderate increase in the abdominal (segment 5). This pattern was similar to that of NOS-positive neurons, while the number of ChAT-positive neurons decreased toward the aboral, but it was not significantly different among segments 3 to 5. The number of ChAT-positive motor endplates increased toward the aboral, with the highest number in segment 5. The proportion of coinnervated motor endplates was approximately 80% in segments 1 to 4, but approximately 66% in segment 5. NPY-IR was localized in some nerve terminals among the smooth muscles of the muscularis mucosa and some NOS- or ChAT-positive esophageal intrinsic neurons. ENK-8-IR was found in some NOS- or ChAT-positive intrinsic neurons, and nerve terminals surrounding intrinsic neurons in the esophagus, but not in motor neurons at the NA or DMV. This study suggests that regional variations in the number of intrinsic neurons and coinnervated striated muscles in the rat esophagus may be involved in local regulations of esophageal motility, and that the rat esophageal intrinsic neurons may contain, at least, motor neurons and interneurons.

Striated Perineal Muscles: Location of Somatic and Autonomic Neurons Projecting to the Male Pig Ischiocavernous Muscle. Neurochemical Features of the Sympathetic Subset.

The location, number and size of the central and peripheral neurons innervating the ischiocavernous muscle (ICM) were studied in male pigs by means of Fast Blue (FB) retrograde neuronal tracing. Moreover the immunohistochemical properties of the sympathetic ganglia were investigated combining the double immunolabeling method. After injection of FB into the left ICM, a mean number of 245.3 ± 134.9 labeled neurons were found in the ipsilateral ventral horn of the S1-S3 segments of the spinal cord (SC), 129.7 ± 45.5 in the L6-S3 ipsilateral and S2-S3 contralateral spinal ganglia (SGs), 2279.3 ± 622.1 in the ipsilateral L2-S2 and contralateral L5-S2 sympathetic trunk ganglia (STGs), 541.7 ± 158 in the bilateral caudal mesenteric ganglia (CMGs), and 78.3 ± 35.8 in the microganglia of the pelvic plexus (PGs). The mean area of the ICM projecting neurons was 1217 ± 69.7 µm2 in the SC, 2737.5 ± 176.5 µm2 in the SGs, 982.8 ± 36.8 µm2 in the STGs, 865.9 ± 39.14 µm2 in the CMGs and 426.2 ± 24.72 µm2 in the PGs. The FB positive neurons of autonomic ganglia contained Dopamine ß hydroxylase, vesicular acetylcholine transporter, neuronal nitric oxyde sinthase, calcitonine gene related peptide, leu-enkephaline, neuropeptide Y, substance P, vasoactive intestinal polypeptide, and somatostatine often colocalized with tyrosine hydroxylase. The particular localization of the motor somatic nucleus, the abundant autonomic innervation and the qualitatively different content of ICM projecting sympathetic neurons suggest a complex regulation of this striated muscle involved in involuntary functions, such as the erection, ejaculation, micturition and defecation. Anat Rec, 301:837-848, 2018. © 2017 Wiley Periodicals, Inc.

In vivo functional and morphological characterization of bone and striated muscle microcirculation in NSG mice.

Organ-specific microcirculation plays a central role in tumor growth, tumor cell homing, tissue engineering, and wound healing. Mouse models are widely used to study these processes; however, these mouse strains often possess unique microhemodynamic parameters, making it difficult to directly compare experiments. The full functional characterization of bone and striated muscle microcirculatory parameters in non-obese diabetic-severe combined immunodeficiency/y-chain; NOD-Prkds IL2rg (NSG) mice has not yet been reported. Here, we established either a dorsal skinfold chamber or femur window in NSG mice (n = 23), allowing direct analysis of microcirculatory parameters in vivo by intravital fluorescence microscopy at 7, 14, 21, and 28 days after chamber preparation. Organ-specific differences were observed. Bone had a significantly lower vessel density but a higher vessel diameter than striated muscle. Bone also showed higher effective vascular permeability than striated muscle. The centerline velocity values were similar in the femur window and dorsal skinfold chamber, with a higher volumetric blood flow in bone. Interestingly, bone and striated muscle showed similar tissue perfusion rates. Knowledge of physiological microhemodynamic values of bone and striated muscle in NSG mice makes it possible to analyze pathophysiological processes at these anatomic sites, such as tumor growth, tumor metastasis, and tumor microcirculation, as well as the response to therapeutic agents.

Morphological study of the iris musculature in diurnal and nocturnal raptors / Estudio morfológico de la musculatura del diafragma en aves rapaces diurnas y nocturnas

In literature it is established that the iris musculature consists of striate muscle fibers in birds while in mammals it consists of smooth muscles. Some authors report the presence of smooth muscle tissue also in the iris of some species of birds. In the present study we report on the iris muscle tissues (type of tissue, direction and mean diameter of muscle fibers or cells) in five species of Accipitriformes (diurnal raptors) and four species of Strigiformes (nocturnal raptors) because they show different way of life depending of their predatory behavior. This morphological study was carried out from raptors died or euthanized at the Wild Life Rescue Centre of Sea and Water birds in Livorno (Italy). From histological examination of iris serial radial sections we find both striated and smooth musculature even if with marked differences among analyzed species, not directly correlated with diurnal or nocturnal lifestyle. Striated fibers are always present, mainly with cross direction, throughout the iris stroma, while the histological differences concern the smooth cells. Indeed, harrier and sparrow hawk (Accipitriformes) and great horned owl and little owl (Strigiformes) show a compact layer of cross smooth muscle cells throughout the iris stroma. In the other species analyzed smooth muscle cells are slightly detectable as scattered or not detectable. Since the cross smooth muscle tissue allows to maintain a myotic state for extended periods of time, our results might be correlated more to the predatory behavior than the taxonomic order.

En la literatura, se establece que la musculatura del iris se compone de fibras musculares estriadas en las aves, mientras que en los mamíferos, la forman los músculos lisos. Algunos autores informan también de la presencia de tejido muscular liso en el iris de algunas especies de aves. El presente estudio informa sobre los tejidos musculares del iris (tipo de tejido, la dirección y diámetro de las fibras musculares o células) en cinco especies de Accipitriformes y cuatro especies de Strigiformes que muestran diferentes hábitos en función de su comportamiento depredador. Este estudio morfológico se realizó en aves rapaces que murieron o fueron eutanasiadas en el Centro de Vida Salvaje de Rescate de Aves Marinas y Acuáticas de Livorno (Italia). El examen histológico de secciones seriadas radiales del iris mostró la presencia tanto de musculatura estriada como lisa, aunque con marcadas diferencias entre las especies analizadas, pero sin correlación directa con el estilo de vida diurna o nocturna. Las fibras estriadas estuvieron siempre presentes, principalmente en dirección transversal a lo largo del estroma del iris, mientras que las diferencias histológicas fueron de las células lisas. Tanto el aguilucho y el gavilán (Accipitriformes) como el buho real y el mochuelo (Strigiformes) mostraron una capa compacta de células musculares lisas transversales en todo el estroma del iris. En las otras especies analizadas, las células musculares lisas fueron ligeramente detectables de manera dispersa o no detectables. Dado que el tejido del músculo liso transversal permite mantener un estado miótico durante largos períodos de tiempo, nuestros resultados podrían estar más correlacionados con el comportamiento depredador, y no con el orden taxonómico.

Effects of 14 weeks resistance training on muscle tissue in Wistar rats / Efecto de 14 semanas de entrenamiento de resistencia en el tejido muscular de ratas Wistar

The objective of the present study was to analyze the effects of 14 weeks of resistance training on muscle tissue in Wistar rats. 20 male Wistar rats were used in the study; 10 allocated to the untrained group (Group 1) and 10 to the trained (Group 2). The physical training (PT) program consisted of four sets of ten water jumps, three times a week for 14 weeks. A progressive increase in load was applied from the14nd to the 42nd day. Following this, the animals were euthanized with an overdose of potassium chlorate (100 mg/kg) applied intraperitoneally. The ventral portion of the gastrocnemius muscle was removed for histological processing. The muscles were frozen in liquid nitrogen and cut into thicknesses of 5 µm using a rotative microtome. The sections were stained with hematoxylin-eosin for general analysis of the structure of muscles and analysis of the area of muscle fibers. The reaction with NADH-TR was utilized for differentiation between fast twitch (FT) and slow twitch (ST) fibers. The sections subjected to staining and histochemical reactions were observed in normal and polarized light and photomicrographed using a microscope (Zeiss®). The measurement of muscle fibers was performed using AxioVision software (Zeiss®). Statistical analysis was performed using the Student t test for analysis of the samples average. An average area of 5061.29 µm2 for Group 1 versus 5768.93 µm2 for Group 2 was observed. It can be concluded that 14 weeks of training with water jumps was effective in increasing muscle area. An increase in transverse area section (TAS) of ST and FT was also verified in the trained group.

El objetivo fue investigar los efectos de 14 semanas de entrenamiento de resistencia sobre el tejido muscular de ratas Wistar. Fueron utilizadas 20 ratas, 10 en el grupo sin entrenamiento (Grupo 1) y 10 con entrenamiento (Grupo 2). El programa de entrenamiento físico estaba compuesto de cuatro series con 10 saltos acuáticos, tres veces en la semana, durante 14 semanas. Un aumento progresivo de la carga fue aplicado desde el día 14 al día 42. Los animales fueron eutanasiados con clorhidrato de potasio (100 mg/kg) intraperitoneal. La parte ventral del músculo gastrocnemio fue removida para el análisis histológico. La musculatura fue congelada en nitrógeno líquido y cortada con 5 µm de espesor con micrótomo rotatorio. La coloración fue H-E para el análisis del músculo y área en las fibras musculares. La reacción com NADH-TR fue utilizada para la comparación entre las fibras rápidas (FR) y fibras lentas (FL). Las reacciones histoquímicass se observaron bajo microscópio de luz (Zeiss®) y sobre las microfotografias obtenidas se realizaron las mediciones con el programa Axio Vision (Zeiss®). El análisis estadístico se realizó con la prueba t de student para comparación de medias. Se observó una media de 5061,29 µm2 en el Grupo 1 y 5768,93 µm2 en Grupo 2. Es posible concluir que 14 semanas de programa de entrenamiento físico con 10 saltos acuáticos son capaces de aumentar el área del músculo. Un aumento del área transversal de las FR y FL fue observado en el grupo 2.

Lack of striated muscle fibers in the longitudinal anal muscle of elderly Japanese: a histological study using cadaveric specimens.

PURPOSE AND METHODS: The aim of this study is to investigate variations in the longitudinal anal muscle (LAM), especially in the meeting pattern between the levator ani and rectum at the origin of the LAM. We examined the histology of the anal canal and the lower rectum of 50 cadavers (25 males, 25 females) of elderly Japanese individuals with the aid of immunohistochemistry. RESULTS: We observed two patterns in the meeting site between the levator ani and the rectum. In type 1, observed in 26 specimens, the smooth muscle-rich fascia lining the internal or medial aspect of the levator ani (i.e., the fascia pelvis parietalis or endopelvic fascia) was connected to the external muscle layer. In type 2, observed in 24 specimens, multiple intramuscular septa of the levator ani were attached to a smooth muscle mass, with the latter joining the external smooth muscle layer of the rectum. However, 21 specimens (6 type 1 and 15 type 2) carried few smooth muscles at the meeting site. We did not find any striated muscle in the LAM, although this might have been the result of age-associated degeneration. Thus, active traction of the pelvic viscera by the LAM seemed unlikely in elderly Japanese. CONCLUSIONS: Rather than playing an active role, as suggested by the integral pelvic floor theory, the LAM seemed to be an elastic skeleton that maintains the shape of the anal canal.

Regulation of structure and function of sarcomeric actin filaments in striated muscle of the nematode Caenorhabditis elegans.

The nematode Caenorhabditis elegans has been used as a valuable system to study structure and function of striated muscle. The body wall muscle of C. elegans is obliquely striated muscle with highly organized sarcomeric assembly of actin, myosin, and other accessory proteins. Genetic and molecular biological studies in C. elegans have identified a number of genes encoding structural and regulatory components for the muscle contractile apparatuses, and many of them have counterparts in mammalian cardiac and skeletal muscles or striated muscles in other invertebrates. Applicability of genetics, cell biology, and biochemistry has made C. elegans an excellent system to study mechanisms of muscle contractility and assembly and maintenance of myofibrils. This review focuses on the regulatory mechanisms of structure and function of actin filaments in the C. elegans body wall muscle. Sarcomeric actin filaments in C. elegans muscle are associated with the troponin-tropomyosin system that regulates the actin-myosin interaction. Proteins that bind to the side and ends of actin filaments support ordered assembly of thin filaments. Furthermore, regulators of actin dynamics play important roles in initial assembly, growth, and maintenance of sarcomeres. The knowledge acquired in C. elegans can serve as bases to understand the basic mechanisms of muscle structure and function.

Anatomy and ontogeny of a novel hemodynamic organ in zebrafish.

The zebrafish maxillary barbel can protract and retract in response to stimuli, and appears connected to a prominent blood sinus on the lateral aspect of the maxillary bone. However, the mechanism of barbel movement is not described. Using whole-mount phalloidin staining of the sinus region, we observed long filamentous actin cables, suggesting highly organized vascular smooth muscle cells, surrounding an endothelial chamber. Although the chamber is variably filled by erythrocytes in vivo, cardiac injection of fluorescent dextrans shows that it consistently contains plasma. Full-thickness confocal imaging of dextran-injected adults containing EGFP(+) endothelial cells revealed a vascular complex with three compartments, here named the distal bulb, central chamber, and accessory chamber. The early ontogeny of all three compartments was confirmed in a whole-mount series of Tg(fli1a:EGFP) juveniles. In wild type adults, the fine structure of each chamber was studied using paraffin- and plastic-section histochemistry and transmission electron microscopy. The distal bulb and central chamber have smooth muscle coats with luminally-elongated septa, forming semi-detached blood-filled lacunae. The central chamber walls and septa are extensively innervated by small, unmyelinated axons, as confirmed by immunohistochemical detection of acetylated tubulin, a component of axonal cytoplasm. The accessory chamber appears neither innervated nor muscularized, but is an endothelial cul-de-sac with a thickened elastic adventitia, suggesting an extensible fluid reservoir. We propose that we have identified a new organ in zebrafish, the maxillary barbel blood sinus, whose neurovascular specializations may contribute to zebrafish sensory biology and appendage control.

The length-tension curve in muscle depends on lattice spacing.

Classic interpretations of the striated muscle length-tension curve focus on how force varies with overlap of thin (actin) and thick (myosin) filaments. New models of sarcomere geometry and experiments with skinned synchronous insect flight muscle suggest that changes in the radial distance between the actin and myosin filaments, the filament lattice spacing, are responsible for between 20% and 50% of the change in force seen between sarcomere lengths of 1.4 and 3.4 µm. Thus, lattice spacing is a significant force regulator, increasing the slope of muscle's force-length dependence.

First comparative study of primate morphological and molecular evolutionary rates including muscle data: implications for the tempo and mode of primate and human evolution.

Here we provide the first report about the rates of muscle evolution derived from Bayesian and parsimony cladistic analyses of primate higher-level phylogeny, and compare these rates with published rates of molecular evolution. It is commonly accepted that there is a 'general molecular slow-down of hominoids', but interestingly the rates of muscle evolution in the nodes leading and within the hominoid clade are higher than those in the vast majority of other primate clades. The rate of muscle evolution at the node leading to Homo (1.77) is higher than that at the nodes leading to Pan (0.89) and particularly to Gorilla (0.28). Notably, the rates of muscle evolution at the major euarchontan and primate nodes are different, but within each major primate clade (Strepsirrhini, Platyrrhini, Cercopithecidae and Hominoidea) the rates at the various nodes, and particularly at the nodes leading to the higher groups (i.e. including more than one genera), are strikingly similar. We explore the implications of these new data for the tempo and mode of primate and human evolution.

Sensory and autonomic neurons project both to the smooth retractor penis and to the striated bulbospongiosus muscles. Neurochemical features of the sympathetic subset.

Aim of the present study was to verify, by means of double retrograde neuronal tracers technique, the hypothesis that a subpopulation of sensory and autonomic neurons send collateral axons to both smooth and striated genital muscles. We also wanted to define the neurochemical content of the eventually retrogradelly double labeled (RDL) neurons in the sympathetic trunk ganglia (STG). We used six intact pigs and we injected the tracer Diamidino Yellow (DY) in the smooth left retractor penis muscle (RPM) and the tracer Fast Blue (FB) in the striated left bulbospongiosus muscle (BSM). Rare (2 ± 0.6) RDL neurons were found in the ipsilateral S2 spinal ganglion (SG), 220 ± 42 in the ipsilateral STGs, from L3 to S3, 19 ± 15 in the contralateral S1-S2 ones and 22 ± 5 in the bilateral caudal mesenteric ganglia (CMG). The RDL neurons of the STG were IR for TH (85 ± 13%), DßH (69 ± 17%), NPY (69 ± 23%), nNOS (60 ± 11%), LENK (54 ± 19%), VIP (53±26%), SOM (40 ± 8%), CGRP (34 ± 12%), SP (31 ± 16%), and VAChT (28 ± 3%). Our research highlights the presence of sensory and sympathetic neurons with qualitatively different neurochemical content sending axons both to the smooth RPM and to the striated BSM of the pig. These RDL neurons are likely to project to the smooth vasal musculature to create the ideal physiological conditions in which these muscles can optimize the erectile function.

The simultaneous presence of neuroepithelial cells and neuroepithelial bodies in the respiratory gas bladder of the longnose gar, Lepisosteus osseus, and the spotted gar, L. oculatus.

Anatomical and functional studies on the autonomic innervation as well as the location of airway receptors in the air-bladder of lepisosteids are very fragmentary. These water-breathing fishes share in common with the bichirs the presence of a glottis (not a ductus pneumaticus) opening into the esophagus. In contrast to a high concentration of neuroepithelial cells (NECs) contained in the furrowed epithelium in the lung of Polypterus, these cells are scattered as solitary cells in the glottal epithelium, and grouped to form neuroepithelial bodies (NEBs) in the mucociliated epithelium investing the main trabeculae in the air-bladder of Lepisosteus osseus and L. oculatus. The present immunohistochemical studies also demonstrated the presence of nerve fibers in the trabecular striated musculature and a possible relation to NEBs in these species, and identified immunoreactive elements of this innervation. Tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), 5-HT and neuropeptide immunoreactivities were detected in the intramural nerve fibers. 5-HT and VIP immunopositive nerve fibers are apparently associated with NEBs. TH, VIP and SP immunoreactivities are also present in nerve fibers coursing in the radially arranged striated muscle surrounding the glottis and its submucosa. 5-HT positive neurons are also found in submucosal and the muscle layers of the glottis. The physiological function of the adrenergic and inhibitory innervation of the striated muscle as well as the neurochemical coding and morphology of the innervation of the NEBs are not known. Future studies are needed to provide evidence for these receptors with the capacity of chemoreceptors and/or mechanoreceptors.

Importância do modelo animal para testar hipóteses sobre a fisiopatologia do binômio diabetes e incontinência urinária feminina / Importance of animal model to test hypotheses about the pathophysiology of the binomial diabetes and female urinary incontinence

Objetivos: discutir a importância do estudo de modelos animais para testar hipóteses sobre os mecanismos de continência urinária e fisiopatologia do binômio diabetes incontinência urinária.Fonte de Dados: foi realizada revisão de literatura no PubMed e SciELO. Os descritores utilizados foram diabetes, urinary incontinence, urethra, human e rats.Síntese dos Dados: existe forte correlação entre a gênese da incontinência urinária e o diabetes mellitus. Devido à similaridade entre a distribuição normal da musculatura estriada e da neuroanatomia da uretra em mulheres e em ratas, estes modelos animais vêm sendo cada vez mais utilizados nas pesquisas sobre esses distúrbios.Conclusões: o uso de ratas como modelo animal é apropriado para estudos experimentais que testam hipóteses sobre os mecanismos de continência e a fisiopatologia do binômio diabetes mellitus e incontinência urinária, possibilitando assim, soluções de grande valia na prática clínica.

Aims: To discuss the importance of studying animal models to test hypotheses about the mechanisms of urinary continence and pathophysiology of diabetes and urinary incontinence.Source of Data: A literature review was conducted in PubMed and SciELO. The key words used were diabetes, urinary incontinence, urethra, human and rats.Summary of Findings: There is a strong relation between the genesis of urinary incontinence and diabetes mellitus. Due to the similarity of normal distribution of skeletal muscle and urethra anatomy between humans and rats, these animal models have been used in current research about these disorders.Conclusions: The use of rats as an animal model is suitable for experimental studies that test hypotheses about the mechanisms of continence and pathophysiology of the binomial diabetes mellitus and urinary incontinence, thus enabling solutions of great value in clinical practice.

Transplantation of mature adipocyte-derived dedifferentiated fat (DFAT) cells improves urethral sphincter contractility in a rat model.

OBJECTIVES: To examine the effects of mature adipocyte-derived dedifferentiated fat (DFAT) cell transplantation on urethral tissue regeneration and sphincter function. METHODS: Sixteen female Sprague-Dawley rats underwent vaginal distension (VD) for 3 h. Subsequently, green fluorescence protein (GFP)-labeled DFAT cells (1×10(6) in 20 µL saline, DFAT group, n=8) or saline (20 µL, control group, n=8) were injected into paraurethral connective tissue. Two weeks following VD, leak point pressure (LPP) was measured and an immunohistochemical analysis of the urethra was performed to evaluate urethral sphincter regeneration. RESULTS: The VD model was characterized by atrophy of the urethral sphincter and showed a decrease in LPP. DFAT cell transplantation resulted in a significant improvement of LPP (DFAT group: 37.3±6.4 vs control group: 21.7±5.7 mmHg, P<0.01). Immunohistochemistry revealed that the striated muscle thickness and smooth muscle α-actin-positive area were significantly (P<0.05) larger in the DFAT group than in the control group. DFAT cell transplantation enhanced macrophage accumulation followed by an increased number of cells in the proliferative state. Transplanted DFAT cells were observed in the damaged smooth muscle layer and showed positive staining for smooth muscle α-actin, suggesting conversion into the smooth muscle cell phenotype. CONCLUSIONS: DFAT cell transplantation promotes sphincter muscle regeneration and improves LPP in the rat VD model.

Anorectal anatomy and physiology.

The rectum and anal canal form the last portion of the gastrointestinal tract. The rectum serves as a reservoir for fecal contents, and the anal canal regulates continence and defecation via synchronization of events regulated by complex interactions between sympathetic and parasympathetic nerves, striated and smooth muscle, and environmental factors. Normal function can be compromised by various pathologies. Investigation into these pathologies includes a detailed history and thorough physical exam and can be augmented by a number of different studies, including manometry, electromyelography, defecography, nerve stimulation, and compliance. Some of these techniques have incorporated the use of ultrasound and magnetic resonance imaging.