Longitudinal Muscle Layer Research Articles

Toxicological effects of bituminous coal dust on the earthworm Eisenia fetida (Oligochaeta: Lumbricidae).

The exploitation of coal is an important resource to generate energy worldwide. However, during the processes of coal extraction, transport, and cargo, dust particles are released into the environment. The aim of this study was to determine the toxicological effects of bituminous coal dust (<38 µm), obtained from a sample collected in a coal mine in Colombia, on the annelid Eisenia fetida. The earthworm culture was standardized under laboratory conditions to evaluate mortality, as well as morphological, physiological and histological changes using concentrations varying from 1 to 4% w/w coal dust in artificial soil, after 7, 14, and 28 days of exposure. In addition, an avoidance assay was carried out after 48-h treatment. Histopathological analysis was performed at the end of the experiment. After the sub-chronic exposure, an increase in mortality was observed at the highest coal dust concentration compared to the untreated group. Alterations in morphology and physiology of the exposed annelids were mostly evidenced at the greatest tested concentrations (3-4%) and exposure times (≥14 days). Changes included loss of weight and color, abundant mucus production, constriction, peeling of the epidermis, clitellum involution, violent movements and lethargy. Avoidance of coal dust-polluted soil followed a concentration-response relationship. Histopathological findings revealed changes on the cuticle, as well as in the circular and longitudinal muscle layers in animals living in soils containing 3 and 4% coal particles. In short, E. fetida exposed to coal dust experienced several pathological changes, suggesting that this pollutant may induce population problems in macroinvertebrates present in coal mining areas.

Redescription of Cerebratulus marginatus auct. (Nemertea: Pilidiophora) from Hokkaido, Japan, as a new species.

The heteronemertean Cerebratulus orochi sp. nov. is described based on material collected intertidally at a muddy beach in Akkeshi, northern Japan. For the last 80 years, the species has been confused with Cerebratulus marginatus Renier, 1804; the latter was originally described from the Adriatic and once believed to occur in many places in the northern hemisphere including Japan. Cerebratulus orochi sp. nov. is morphologically different from all the congeners including C. marginatus by the following combination of characters: several layers of diagonal-muscle meshwork coated with connective tissue, proximo-distally distributed in cross section from the distal portion of the body-wall outer longitudinal muscle layer to the cutis-gland zone throughout the anterior portion of the body from the precerebral to the foregut regions; the cephalic vascular system consisting of lateral and mid-dorsal vessels; and the sub-rhynchocoelic vessel possessing a pair of antero-lateral diverticula before the former forks posteriorly into a pair of lower lateral vessels in the post-cerebral, pre-oral region. Previous records of C. marginatus from Japanese waters are no longer considered to be substantiated. Multi-locus phylogenetic analyses based on the mitochondrial 16S rRNA and cytochrome c oxidase subunit I (COI), as well as the nuclear 18S rRNA, 28S rRNA, and histone H3 genes among heteronemerteans comprising the "Cerebratulus clade" indicated that C. orochi sp. nov. was closely related to C. cf. marginatus from the US Pacific coast. A MegaBLAST search at the NCBI website with the 16S rRNA gene sequence from C. orochi sp. nov. followed by a couple of species delimitation analyses suggests that larvae of the species are also distributed in Vostok Bay, Far East Russia.

A novel third mesh-like myometrial layer connects the longitudinal and circular muscle fibers -A potential stratum to coordinate uterine contractions-

Periodic myometrial contraction is one of the important uterine functions to achieve embryo implantation and parturition. Although it is well-known that the mammalian myometrium is composed of longitudinal (outer) and circular (inner) layers, the precise mechanisms that coordinate both muscular contractions to produce peristaltic movements remain unclear. Recently, by treatment with our modified Clear Unobstructed Brain Imaging Cocktails and Computational analysis (CUBIC) tissue-clearing method, we obtained well-contrasted three-dimensional images of the transparent murine ovary using enhanced green fluorescent protein (EGFP) transgenic mice and light-sheet microscopy. Consequently, to investigate accurate anatomical connections between outer and inner myometrial fibers, we observed whole structures of the myometrium using a transparent murine uterus. By this method, we identified a novel muscle layer, a middle layer of the myometrium, which anatomically connects the conventional outer longitudinal and inner circular muscles. This new layer was visualized as a mesh-like structure and this structure was observed throughout the whole uterus from proximal to distal sites. In this area, CD31-positive vessels were abundantly localized around the mesh-like muscle fibers. In addition, CD34-positive uterine telocytes and tubulin β-3-positive nerve fibers were closely located in this middle layer. These findings indicate the presence of a novel mesh-like stratum that connects longitudinal and circular muscle layers, and suggest its coordinating role in myometrial contractions.

Soy flavonoids prevent cognitive deficits induced by intra-gastrointestinal administration of beta-amyloid

BackgroundIn Alzheimer's diseases, beta-amyloid may act as prion-like protein and migrate from the gastrointestinal tract towards the brain. Soy flavonoids have been identified as neuroprotective against cognitive loss in human. Diet with soy flavonoids may be used to slow down the progression of Alzheimer's diseases. Methods and resultsWe performed in-vitro tissue culture experiments using myenteric plexus longitudinal muscle layers isolated from the ileum and colon of ICR mice. Beta-amyloid can be taken up into myenteric neurons and induce neuron degeneration, which is protected by flavonoids compounds, including daidzein, genistein, glycitein and luteolin. We also administered oligomeric beta-amyloid (1–42) (total dose: 8 μg) into the gastrointestinal walls of ICR mice and conducted memory tests and gastrointestinal function assessments after 6 and 12 months. Mice treated with beta-amyloid exhibited minor learning deficits in a T-maze memory test at 6 months and significant memory impairment in a novel object recognition task at 12 months. These impairments were prevented by soy flavonoids. Tracking studies performed using fluorescently tagged beta-amyloid found that, beta-amyloid injected at the stomach can aggregate within the layer of myenteric neurons and migrate to the jejunum or via the vagus nerves to the brain after 1 month. Reductions in the gastrointestinal tissue weight and the spontaneous ileal contraction frequency were also observed at 6 and 12 months, respectively. ConclusionOur findings indicate that beta-amyloid can migrate from the gastrointestinal tract to the brain to induce cognitive impairments. Furthermore, chronic soy flavonoids in drinking water have protective actions.

Laparoscopic Heller Myotomy and Toupet Fundoplication for Achalasia.

Achalasia manifests as failure of relaxation of the lower esophageal sphincter resulting in dysphagia. Although there are several medical and endoscopic treatment options, laparoscopic Heller myotomy has excellent short- and long-term outcomes. This article describes in detail our surgical approach to this operation. Key steps include extensive esophageal mobilization, division of the short gastric vessels, mobilization of the anterior vagus nerve, an extended gastric myotomy (3 cm as opposed to the conventional 1-2 cm gastric myotomy), a minimum 6 cm esophageal myotomy through circular and longitudinal muscle layers, and a Toupet partial fundoplication. We routinely use intraoperative endoscopy both to check for inadvertent full-thickness injury and to assess completeness of the myotomy and the geometry of the anti-reflux wrap.

Mast cell histamine mediates intestinal immune response to early life stress in piglets via histamine 1 receptor (H1R)

Abstract Mast cells are important immune modulators of stress-related gastrointestinal (GI) disorders. Our previous studies investigating early life stress in piglets showed that histamine, a major mast cell granule mediator is released within minutes of early weaning stress and is followed by increased intestinal mucosal expression of histamine receptor subtypes. The precise contribution of histamine to stress-induced GI immune responses is unknown. The objective of this study was to test the hypothesis that stress-induced intestinal immune response is mediated through the histamine 1 receptor (H1R). Fifteen-day-old female Yorkshire piglets were administered either saline vehicle or the H1R antagonist, desloratadine (2 mg/kg; intramuscular), 30 minutes prior to early weaning stress. At weaning, piglets were weaned from their dams and housed in nursery pens with ad libitum access to water. At 24 hours post-weaning, mid-jejunum and mesenteric lymph nodes (MLN) were collected for subsequent qPCR gene expression as well as IHC localization and protein expression analyses. Unweaned control piglets remained with the sow and were collected immediately at weaning. Gene expression for H1R was not influenced by weaning; however, immunohistochemical analysis of H1R revealed increased expression and localization in lamina propria cells and myofibroblasts in jejunal villi and expression in the longitudinal and circular muscle layers in early weaned piglets. In the MLN, weaning increased the expression of TNFα, TGFβ, and β-Integrin. This response was reduced in the group treated with the H1R antagonist. Together, these data demonstrate that histamine via H1R plays an important role in early weaning stress-induced intestinal immune responses.

Enteric Glial Networks Visualized using SOX10 Fluorescent Reporter in Optically‐Cleared Full Thickness Intestinal Tissues

Enteric glia are important components of the enteric nervous system (ENS) that control critical functions of the alimentary canal including motility, fluid and ion transport, and immune barrier. Anatomical assessments of enteric glia to date have utilized microdissected whole‐mount tissue or thin sections to visualize cells in the optically dense matrix of the bowel. The aim of this study was to assess the morphological features of enteric glia throughout the small and large intestines of the mouse in intact full‐thickness preparations. B6.Cg‐Polr2atm1(CAG‐GCaMP5g,‐tdTomato)Tvrd/J mice were bred to homozygosity with B6.Cg‐Tg(SOX10‐cre/ERT2)Vpa mice which were maintained as hemizygous. Mice received a gavage of tamoxifen (5mg in 0.2ml corn oil) for five days at seven to eight weeks of age to induce tdTomato (tdT) expression in glia. Mice were euthanized by CO2 inhalation at 10–20 weeks of age. Jejunum and mid colon segments were opened on the mesenteric border, fixed in 4% paraformaldehyde, immunostained for anti‐S100β, and cleared with Ce3D solution. Tissues were imaged using confocal microscopy and 3D reconstructions were made using Analyze. SOX10‐tdT cells were found in the bowel throughout all layers. In the muscularis externa of both the jejunum and colon, there were extensive networks within myenteric ganglia, intraganglionic fiber tracts, within the circular muscle layer, along fiber tracts ascending through the circular muscle, and rare cells were observed in the longitudinal muscle layer. In the submucosal layer of both the jejunum and colon, SOX‐tdT cells were in submucosal ganglia, along intraganglionic fibers and formed a regular network of processes that extended within the lamina propria surrounding the base of intestinal crypts. In the mucosa, SOX10‐tdT distribution differed between the jejunum and colon. In the colonic mucosa, there were two distinct bands of SOX10‐tdT networks oriented perpendicular to and surrounding all colonic glands which were approximately 120μm in height. These bands were located approximately 20μm and 60μm from the base of the glands. SOX10‐tdT cells were very rarely observed near the luminal surface of the colonic glands. In the jejunal mucosa, there were extensive SOX10‐tdT networks throughout the lamina propria surrounding crypts and extending to the tips of villi. Overlap of SOX10‐tdT and S100β immunoreactivity was nearly 100% throughout all glial populations with two exceptions, only 10–20% of SOX10‐tdT cells had S100β immunoreactivity in the jejunum mucosa and there were submucosal neurons that expressed S100β that did not contain SOX10‐tdT. Collectively, these data demonstrate significant complexity of the glial networks of the intestines with distinct morphological differences between mucosal glia of the colon and jejunum that may implicate different functions of enteric glia in the small and large intestines.Support or Funding InformationSupported by NIH grants R01DK106011, P30DK084567 and DP2AT010875 and Department of Defense grant W81XWH‐18‐1‐0218.Representative SOX10‐tdT fluorescence in projections of 409 or 139 1.22μm‐thick confocal images through the full thickness of either jejunum (left) or colon (right), respectively.Figure 1

Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon.

Because dopamine (DA) has gained increasing evidence as modulator of gut motility, we aimed to characterize dopaminergic response in human colon, evaluating function and distribution of dopamine receptors in circular vs longitudinal muscle strips. Mechanical responses to DA and dopaminergic agonists on slow phasic contractions and on basal tone were examined in vitro as changes in isometric tension. RT-PCR was used to reveal the distribution of dopaminergic receptors. In spontaneous active circular muscle, DA induced an increase in the amplitude of slow phasic contractions and of the basal tone, via activation of D1-like receptors. DA contractile responses were insensitive to neural blockers or to atropine and inhibited by phospholipase C (PLC) pathway inhibitors. In precontracted circular muscle strips, DA, at the higher concentrations tested, caused a relaxant response via activation of D2-like receptors. In the longitudinal muscle, DA caused only muscular relaxation due to activation of D2-like receptors. DA relaxant responses were insensitive to neural blockers or to nitric oxide synthase inhibitor and reduced by a wide-spectrum K+ channel blockers. Transcripts encoding for all the dopaminergic receptor subtypes was observed in both circular and longitudinal preparations. Dopamine is able to modulate contractile activity of the human colon. In the circular muscle layer, DA induces mainly muscular contraction activating non-neural D1-like receptors, coupled to PLC/IP3 pathway. In the longitudinal muscle layer, DA induces muscular relaxation acting on non-neural D2-like receptors leading to the increase in K+ conductance.

Motor Function of the Gastrointestinal Tract and Biliary Tract in Pancreatic Tumors

Abstract The goal is to identify motor disorders of the Gastrointestinal Tract and Biliary tract (GIT and RVC) in tumors of the pancreas. Material and methods: There were 8 patients with pancreatic adenoma under observation: 75% of women aged 67.2 ± 3.5 years and 25% of men aged 57.3 ± 5.9 years. The diagnosis of a pancreatic tumor was made on the basis of abdominal sonography, aiming at the pancreas. The motor function of the gastrointestinal tract and GI departments was studied Electromyographically (EMG) by applying silver bipolar electrodes to the projection area of the registered organ on the anterior abdominal wall. The analysis of electromyograms was performed using the Conan-M hardware and software complex with a bandwidth of 1-10 Hz. Results: In pancreatic tumors, hypermotor dyskinesia of the longitudinal and oblique muscle layers of the stomach, hypermotor dyskinesia of the duodenum were observed. Hypermotor dyskinesia of the jejunum, hypomotor dyskinesia of the right parts of the colon, hypomotor dyskinesia of the proximal part of the descending colon due to a pronounced spasm of the circular muscle layer. Keywords Electromyography; Pancreatic tumors

Distinct alterations of gut morphology and microbiota characterize accelerated diabetes onset in nonobese diabetic mice

Distinct alterations of gut morphology and microbiota characterize accelerated diabetes onset in nonobese diabetic mice

Human adipose-derived mesenchymal stem cells accelerate decellularized neobladder regeneration.

Decellularized natural bladder matrices (neobladders) represent an exciting means to regenerate the bladder following bladder cancer-associated cystectomy. In this study, we compare the evolution of decellularized matrices with recellularized matrices by seeding it with human adipose-derived mesenchymal stem cells (ADSC) after implantation following partial cystectomy in rats. We discovered significant anatomical differences since 10 days after neobladder implantation with the ADSC-containing matrices promoting a significant recovery of mature p63- and cytokeratin 7-positive urothelium. We also discovered significantly induced expression of the vimentin mesoderm marker in the submucosal layer in ADSC-seeded matrices. Interestingly, we found a higher expression of smooth muscle actin in transversal and longitudinal smooth muscle layers with ADSC-seeded matrices. Furthermore, ADSC also showed increased vascularization and nerve innervation of the neobladder as determined by the distribution of CD31 and S100β reactivity, respectively. We believe that ADSC and their paracrine-acting pro-regenerative secretome within decellularized matrices represent an efficient bladder substitution strategy; however, we require a fuller understanding of the mechanisms involved before clinical studies can begin.

Histomorphological and histochemical structure of the midgut and hindgut of the Caucasian honey bee (Apismelliferacaucasia)

The Caucasian honey bee (Apis mellifera caucasia subspecies of Apis mellifera L.) is one of the most common and prominent honey bee breeds in Turkey. The morphometry of endemic honey bee breeds has been extensively studied, but little attention has been given to the microscopic morphology of these bees. The aim of the current study was to describe for the first time the histomorphology of the midgut and hindgut of the Caucasian honey bee in Turkey. A total of 20 local Caucasian adult honey bee workers were sampled for histomorphological and histochemical analysis. The midgut epithelium consisted of epithelial cells with different morphologies. Acidic, neutral, and mixed mucosubstances were found in the luminal surfaces of the cells and peritrophic membranes. The ileum mostly consisted of an epithelium containing columnar cells that usually had basal nuclei. The rectum of adult workers had a single-layered epithelium externally, involving a layer of inner circular and outer longitudinal muscles. There were 6 long hollow rectal pads in the median-anterior area of the rectum. These results contribute in detail to our understanding of the histomorphology of the Caucasian (A. m. caucasia) honey bee.

Spatiotemporal Mapping of the Contracting Gravid Uterus of the Rabbit Shows Contrary Changes With Increasing Gestation and Dosage With Oxytocin.

Spontaneous and oxytocin induced contractile activity was quantified in the bicornuate uteri of pregnant rabbits maintained in situ, using data from two- and uni- dimensional video spatiotemporal maps (VSTM) of linear and area strain rate and compared statistically. Spontaneous contractions occurred over a range of frequencies between 0.1 and 10 cpm, in gravid animals at 18–21 and at 28 days of gestation, and propagated both radially and longitudinally over the uterine wall overlying each fetus. Patches of contractions were randomly distributed over the entire surface of the cornua and were pleomorphic in shape. No spatial coordination was evident between longitudinal and circular muscle layers nor temporal coordination that could indicate the activity of a localized pacemaker. The density and duration of contractions decreased, and their frequency increased with the length of gestation in the non-laboring uterus. Increasing intravenous doses of oxytocin had no effect on the mean frequencies, or the mean durations of contractions in rabbits of 18–21 days gestation, but caused frequencies to decrease and durations to increase in rabbits of 28 days gestation, from greater spatial and temporal clustering of individual contractions. This was accompanied by an increase in the distance of propagation, the mean size of the patches of contraction, the area of the largest patch of contraction and the overall density of patches. Together these results suggest that progressive smooth muscle hypertrophy and displacement with increasing gestation is accompanied by a decrease in smooth muscle connectivity causing an increase in wall compliance and that oxytocin restores connectivity and decreases compliance, promoting volumetric expulsion rather than direct propulsion of the fetus by peristalsis. The latter effects were reversed by the β2 adrenergic receptor agonist salbutamol thus reducing area of contraction, and the duration and distance of propagation.

Nerves innervating copulatory organs show common FMRFamide, FVRIamide, MIP and serotonin immunoreactivity patterns across Dinophilidae (Annelida) indicating their conserved role in copulatory behaviour

BackgroundMales of the microscopic annelid family Dinophilidae use their prominent glandomuscular copulatory organ (penis) to enzymatically dissolve the female’s epidermis and thereafter inject sperm. In order to test for putative conserved copulatory structures and neural orchestration across three dinophilid species, we reconstructed the reproductive myo- and neuroanatomy and mapped immunoreactivity patterns against two specific neurotransmitter markers with reported roles in invertebrate male mating behaviour (FVRIamide, MIP) and three general neural markers (acetylated α-tubulin, serotonin, FMRFamide).ResultsSeminal vesicles (one or two pairs), surrounded by a thin layer of longitudinal and circular muscles and innervated by neurites, are found between testes and copulatory organ in the larger males of Dinophilus vorticoides and Trilobodrilus axi, but are missing in the only 0.05 mm long D. gyrociliatus dwarf males. The midventral copulatory organ is in all species composed of an outer muscular penis sheath and an inner penis cone. Neurites encircle the organ equatorially, either as a ring-shaped circumpenial fibre mass or as dorsal and ventral commissures, which are connected to the ventrolateral nerve cords. All three examined dinophilids show similar immunoreactivity patterns against serotonin, FMRFamide, and FVRIamide in the neurons surrounding the penis, supporting the hypotheses about the general involvement of these neurotransmitters in copulatory behaviour in dinophilids. Immunoreactivity against MIP is restricted to the circumpenial fibre mass in D. gyrociliatus and commissures around the penis in T. axi (but not found in D. vorticoides), indicating its role in controlling the copulatory organ.ConclusionsThe overall myo- and neuroanatomy of the reproductive organs is rather similar in the three studied species, suggesting a common ancestry of the unpaired glandomuscular copulatory organ and its innervation in Dinophilidae. This is furthermore supported by the similar immunoreactivity patterns against the tested neurotransmitters around the penis. Smaller differences in the immunoreactivity patterns around the seminal vesicles and spermioducts might account for additional, individual traits. We thus show morphological support for the putatively conserved role of FMRFamide, FVRIamide, MIP and serotonin in dinophilid copulatory behaviour.

Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images.

Magnetic resonance images of the anal canal show small, circular, low‐intensity areas arranged in a row and a high‐intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0–1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low‐ and high‐intensity areas. Clin. Anat. 33:619–626, 2020. © 2019 Wiley Periodicals, Inc.

Depth of Invasion into the Circular and Longitudinal Muscle Layers in T2 Esophageal Squamous Cell Carcinoma Does Not Affect Prognosis or Lymph Node Metastasis: A Multicenter Retrospective Study.

Although a greater depth of tumor invasion is correlated with a poorer prognosis in esophageal squamous cell carcinoma (ESCC), it remains controversial whether T2 ESCC should be subclassified by circular and longitudinal muscle invasion. We conducted a multicenter retrospective study to evaluate the relationship between the depth of invasion and long-term outcome and to identify the clinical significance of subclassifying T2 ESCC. Patients with T2 ESCC who underwent esophagectomy at two different institutes between January 2009 and December 2017 were analyzed retrospectively. ESCC with circular and longitudinal muscle invasion was defined as T2 circular and T2 longitudinal ESCC, respectively. Survival outcomes and risk factors for lymph node metastasis (LNM) were evaluated by univariate and multivariate analyses. In addition, data from stage T1b ESCC cases during the same period were retrieved for use as a comparison cohort to evaluate the prognostic significance of the T2 substage. A total of 536 T2 ESCC patients were eligible, and 192 (36%) patients developed LNM. No significant difference was found in general characteristics between the T2 circular and T2 longitudinal ESCC groups (n = 219 and n = 317, P > 0.05), except for tumor location (P = 0.02). The T2 substage was not significantly correlated with survival on univariate or multivariate analysis (P = 0.30 and P = 0.34, respectively). Multivariate analysis also indicated that the T2 substage was not an independent risk factor for LNM (P = 0.15). When patients with stage T1b ESCC were considered, their survival time was significantly different from that of patients with T2 circular and T2 longitudinal disease (P = 0.01). The depth of tumor invasion into the circular and longitudinal muscle layers in T2 ESCC does not affect the prognosis or risk of LNM.

A structured review on the female urethral anatomy and innervation with an emphasis on the role of the urethral longitudinal smooth muscle.

A damaged sphincteric unit or support system, unstable urethral deformability or damaged sensory innervation are all potential causes of a dysfunctional urethral sphincter. With the current improvement in pharmacological targets and urodynamic understanding, studies have begun quantifying individual structures and their importance in closure pressure and consequently urethral continence. However, when it comes to the function of the longitudinal urethral smooth muscle layer, there is currently no consensus. The intent of this structured review is to critically examine literature regarding the female urethral anatomy and closure mechanism. We hypothesized that the longitudinal smooth muscle is a prerequisite for sufficient urethral closure and not merely involved during micturition. Overall opinions on a dysfunctional closure mechanism are controversial. Nonetheless, basic mechanics may be applied to understand simple urodynamics. With the assumption of longitudinal muscles forming a plug when contracted, this could have a substantial effect on the continence mechanism.

Morphology and microcirculatory structure of the urethra of the pig: Urologic surgical interest

The urethra of the sow can play an important role in the surgical revascularization or in the reconstructive surgery. However, the urethra can be easily injured if it possessed well architecture and vascularization. We investigated the morphological structure and vasculature features of the urethra to improve surgical results. Eight pelvises of sow were investigated. The block was cuts according to the segments of the urethra. They were made transparent according to the sagittal and transvers planes and examined trough Chinese ink agar injection. The adventia of both portions of the urethra of the sow (pelvic and perineal) were dependent on the collaterals of the internal iliac arteries and internal pudendal arteries. The veins of the periphery of the urethra derived from the muscle layers and the chorion and ran into a network in contact with arteries. The arteries of the striated muscle layer originated from the adventitial arteries of the anterior and lateral regions of the urethra. The chorion was depended on long vessels from the adventitious network and the terminal branches of the vessels of the inner longitudinal muscle layer. The arteries of the urethrovaginal septum were thin and came from the branches of the vaginal artery. The urethra of the sow was sheathed by the pelvic fascia lined with the elevated muscle of anus. They were well vascularized and can be safety exposed and preserved during experimental surgical dissection with careful drilling.Keys words: Sow urethra, morphology, structure, microvascularization.

MORPHOLOGICAL CHANGES IN THE MUSCLE LAYERS OF SMALL INTESTINE IN THE SHORT BOWEL SYNDROME IN EXPERIMENT

Introduction. Patients with the short bowel syndrome often have intestinal dilatation which impairs intestinal functions. Changes in the muscle intestinal layers, which cause this condition, are not studied well yet. Purpose. To study the role of small intestine muscle layers in the intestinal adaptation and dilatation in the short bowel syndrome. Materials and methods. 22 rats were taken into the experimental trial; short bowel syndrome was modelled in 12 of them; 10 other rats which had only laparotomy were in the control group. The diameter and thickness of muscle layers in the small intestine and ileum were studied. Results. In the short bowel syndrome, one can observe a significant dilatation of the small intestine and ileum. Thickness of longitudinal and circular layers of the small intestine was significantly larger in rats with the short bowel syndrome in comparison to the control group. In the ileum, only the circular muscle layer was hypertrophied; there was no difference in the thickness of longitudinal muscle layer in rats with the short bowel syndrome and in rats from the control group. Conclusion. In rats with the short bowel syndrome, morphological changes occur not only in the mucous layer, but also in muscle layers of the small intestine what is manifested by the intestinal dilatation and hypertrophy of muscle layers. These changes are results of intestinal adaptation and are pathophysiological for the short bowel syndrome.

Characterization of projections of longitudinal muscle motor neurons in human colon.

The enteric nervous system contains inhibitory and excitatory motor neurons which modulate smooth muscle contractility. Cell bodies of longitudinal muscle motor neurons have not been identified in human intestine. We used retrograde tracing ex vivo with DiI, with multiple labeling immunohistochemistry, to characterize motor neurons innervating tenial and inter-tenial longitudinal muscle of human colon. The most abundant immunohistochemical markers in the tertiary plexus were vesicular acetylcholine transporter, nitric oxide synthase (NOS), and vasoactive intestinal polypeptide (VIP). Of retrogradely traced motor neurons innervating inter-tenial longitudinal muscle, 95% were located within 6mm oral or anal to the DiI application site. Excitatory motor neuron cell bodies, immunoreactive for choline acetyltransferase (ChAT), were clustered aborally, whereas NOS-immunoreactive cell bodies were distributed either side of the DiI application site. Motor neurons had small cell bodies, averaging 438+18µm2 in cross-sectional area, similar for ChAT- and NOS-immunoreactive subtypes. Motor neurons innervating the tenia had slightly longer axial projections, with 95% located within 9mm. ChAT-immunoreactive excitatory motor neurons to tenia were clustered aborally, whereas NOS-immunoreactive inhibitory motor neurons had both ascending and descending projections. VIP immunoreactivity was rarely present without NOS immunoreactivity in motor neurons. Tenial and inter-tenial motor neurons innervating the longitudinal muscle have short projections. Inhibitory motor neurons have less polarized projections than cholinergic excitatory motor neurons. Longitudinal and circular muscle layers are innervated by distinct local populations of excitatory and inhibitory motor neurons. A population of human enteric neurons that contribute significantly to colonic motility has been characterized.