The development of the bladder trigone, the center of the anti-reflux mechanism

The urinary tract is an outflow system that conducts urine from the kidneys to the bladder via the ureters that propel urine to the bladder via peristalsis. Once in the bladder, the ureteral valve, a mechanism that is not well understood, prevents backflow of urine to the kidney that can cause severe damage and induce end-stage renal disease. The upper and lower urinary tract compartments form independently, connecting at mid-gestation when the ureters move from their primary insertion site in the Wolffian ducts to the trigone, a muscular structure comprising the bladder floor just above the urethra. Precise connections between the ureters and the trigone are crucial for proper function of the ureteral valve mechanism; however, the developmental events underlying these connections and trigone formation are not well understood. According to established models, the trigone develops independently of the bladder, from the ureters, Wolffian ducts or a combination of both; however, these models have not been tested experimentally. Using the Cre-lox recombination system in lineage studies in mice, we find, unexpectedly, that the trigone is formed mostly from bladder smooth muscle with a more minor contribution from the ureter, and that trigone formation depends at least in part on intercalation of ureteral and bladder muscle. These studies suggest that urinary tract development occurs differently than previously thought, providing new insights into the mechanisms underlying normal and abnormal development.     

Neo-regeneration of urinary bladder: a desired metaplasia of autologous membrane from rectosigmoid colon containing stem cells of intestinal crypts

The current management of diseases of urinary bladder requiring resection is by augmentation cystoplasty or transplantation of ureters. Transplantation of ureters is associated with morbidity and mortality. Ideal management will be by regenerating urinary bladder in vivo. Neo-regeneration of tissues and organs like abdominal wall, aponeurosis etc., has been attempted and patented. After neo-regeneration of mesoderm tissues and organs, regeneration of urinary bladder (developed from endoderm) was. In vivo surgical techniques were developed in dogs. It is known that the embryonic morphogenesis of urinary bladder is from uro-genital sinus of hind gut. A membrane, containing endoderm stem cells in crypts of recto-sigmoid colon, was surgically isolated and colonized with remnant of urinary bladder wall after extensive resection. Experimental study was performed in dogs, for 60 days to one and a half year. Regeneration of all the layers of tissues of the wall of urinary bladder was observed. The neo-regeneration phenomenon has been recognized as "desired metaplasia". The regenerated neo tissue/organ on histological examination and cystometry studies was found compatible with normal urinary bladder. The hypothesis, neo-regeneration and desired metaplasia, is discussed.     

Genetic Basis of Ureterocele

Congenital anomalies of the kidney and urinary tract (CAKUT) form a group of heterogeneous disorders that affect the kidneys, ureters and bladder, with frequent asynchronous presentations and multiple CAKUT associations in the same individual. Urinary tract formation is a complex process, dependent of the interaction of multiple genes and their sub-product. The same genic alterations can lead to different molecular expressions and different morphological anomalies. The ureterocele is a cystic dilation of the distal intramural ureter, resulting in obstruction of urine flow, dilation of the ureter and renal pelvis and loss of renal function. Two key steps in the urinary tract ontogenesis may be related to ureterocele development: formation and migration of the ureteric bud and its incorporation in the bladder. This review aims to describe the morphological, cellular and biochemical steps, as well as the genes involved in the occurrence of this anomaly.     

Structure of the urinary bladder in the Pacific cod

The urinary bladder of the Pacific cod,Gadus macrocephalus was investigated. A pair of ureters was found to unite and form a sac-like protrusion on the posteroventral aspect of the gonad. This protrusion was confirmed as the urinary bladder based on its histology and the presence of ammonia and urea in the fluid within this structure. The urinary bladder consisted of a central lumen and two lateral expansions found on the right and left sections. The luminal epithelial cells of the Pacific cod urinary bladder, unlike those of other animals, were characterized by microvilli on the free surface, and the presence of a number of vesicles and mitochondria across the apical portion on the cells. This suggests that the luminal epithelium of the urinary bladder might be actively engaged in transportation of water or other materials from the urine. The Pacific cod urinary bladder may therefore be closely associated with osmoregulation by reabsorbing water from the urine. Ammonia-N and urea-N levels of 65–213 μg/dl and 1.5–3.5 mg/dl were measured in the fluid which filled the urinary bladder.     

Adrenergic innervation of the ureters, urinary bladder, and urethra in pigs

Studies were conducted on 4 sexually mature and 4 immature pigs. Scraps of the ureters, urinary bladder, and urethra were cut with a freezing microtome. Fluorescence method of Torre and Surgeon (1976) was used to reveal the adrenergic innervation. It was found that the ureters were weakly supplied with the adrenergic nerves; most of the nerves were located in the muscular and submucosal membranes. Apex of the urinary bladder possessed the weakest innervation. More nerves were found in particular layers of the bladder corpus whereas bladder trigonum and cervix possessed numerous nerves. Adrenergic innervation of the urethra was similar to that of the urinary bladder's cervix. Adrenergic nerves were present in the serous and muscular membranes of both the urinary bladder and the urethra. Part of the nerve fibres was connected with blood vessels of the organs under study.     

Adrenergic innervation of the lower urinary tract in cattle

Studies were carried out on 8 sexually immature male calves. Sections of the ureters, urinary bladder, and urethra were cut with a freezing microtome and the method of Ky?s?la et al. (1980) was used to visualize the adrenergic nerve fibres. It was found that bovine ureters possessed weak innervation; most of the nerves was located in the muscular membrane, and only in the paravesical part, sparse nerve fibres were found in the submucosa of this one. Apex of the urinary bladder was more weakly supplied with the adrenergic nerves than the corpus, whereas bladder's trigonum and cervix possessed numerous nerve fibres in both muscular and submucosal membranes. The distribution pattern of adrenergic nerves in the urethra was similar to that of urinary bladder's cervix. The presence of adregeneric nerve fibres was found in submucosal layer of both the urinary bladder and the urethra. Part of the nerves was connected with blood vessels of the organs under study.     

Urolithiasis and cystotomy in the rabbit

Cystotomy is a surgical incision into the urinary bladder, which may be required for removal of calculi, diagnosis of tumors or refractory urinary tract infections, or repair of ectopic ureters and ruptured bladders. This column describes the indications and techniques for cystotomy in the rabbit.     

Some Coelozoic Myxosporida From New Zealand Fishes: Family Sphaerosporidae1

SYNOPSIS. The trophic stages and spores of Sphaerospora undulans n. sp. from the urinary bladder, and ureters, and oviducts of Caulopsetta scapha, and the urinary bladder and ureters of Peltorhamphus novaezelandiae are described. An undescribed species from Genypterus blacodes is also mentioned. The host fishes were taken in New Zealand.     

Schistosoma haematobium: experimental infection in capuchin monkey, Cebus apella

South American capuchin monkeys (Cebus apella) have been included in a series of nonhuman primates under evaluation for their potential use as models in a study of the basic biology of Schistosoma haematobium. Emphasis has been given to involvement of the urogenital system, a prominent feature of infection in man. Preliminary observations on Cebus apella with moderate numbers of S. haematobium from Iran showed that there may be serious involvement of the urogenital system with development of pronounced hydronephrosis accompanied by pathobiological alteration of the urinary bladder, ureters, and kidneys. There were heavy deposits of parasite eggs in the major viscera.     

三聚氰胺泌尿系统结石大鼠模型的研究

目的观察工业原料三聚氰胺连续给药诱发SD大鼠尿结石的成模情况。方法60日龄SPF级SD大鼠130只,雌雄各半,体质量（200＋24）g,随机分为给药5个组和空白对照组各20只,溶媒对照组10只。给药组分别给予三聚氰胺0．05、0．1、0．2、0．3、0．4g／（kg·d）连续灌胃;溶媒对照组灌胃10g／L甲基纤维素蒸馏水2mL／（只·d）,空白对照组灌胃无菌水2mL/（只·d）。采用体视显微镜观察大鼠肾脏、输尿管和膀胱形态改变,比较各组肾脏、膀胱的质量和脏器指数,观察大鼠CREA、BUN、UA、Ca、P、Mg含量变化。结果0．4g／kg组给药20d,0．2、0．4g／kg组给药30d,肌酐高于空白对照组;0．4g/kg组给药30d,尿素氮、尿酸高于空白对照组。给药20d各组血钙、磷、镁均偏低。给药30d,0．05、0．2、0．3、0．4g／kg组左肾质量比空白对照组增加。各组肾脏大小、颜色均与正常对照组比较接近,未见结石和明显黄色沉淀物,但有部份肾脏在皮、髓质交界处有点状或片状出血灶。输尿管未见结石。部分膀胱粘膜充血,部分雄性大鼠出现膀胱结石,其中给药20d各组雄性大鼠出现率为52％（13／25）,30d各组出现率为56％（14／25）,膀胱结石颜色多为淡黄色混合白色、白色。结论（0．05～0．4）g/kg三聚氰胺连续给药30d,对肾脏损害轻微,可诱发雄性大鼠产生膀胱结石。     

Neutral aminopeptidase: a potential marker enzyme of the amphibian urinary bladder epithelial cell apical membrane

Antidiuretic hormone induces, in the apical plasma membrane of amphibian urinary bladder epithelial cells, the exocytotic insertion of intramembranous particle aggregates that probably contain water channels. Purification of the apical membrane is a way to characterize the aggregates. The isolation of such purified membranous fractions involves the use of specific exogenous or endogenous markers. One of them could be the neutral aminopeptidase (AP), whose activity was detected in urinary bladder. Enrichment in AP activity was observed in plasma membrane preparations compared to cell homogenates (X2.7). However, a large part of the enzyme activity was also recovered in the soluble fraction of the preparation, suggesting large proteolysis of the protein. The enzyme presents a low optimal pH (6.4) and a high specificity for proline-p-nitroanilide as compared to the AP present in kidneys and intestines. To localize the protein in the amphibian bladder epithelium, an immunological approach was necessary due to the low activity of the enzyme in this tissue. The low enzymatic activity also prevented the purification of sufficient amounts of the urinary bladder AP as antigen, and we prepared antibodies against purified AP from frog or toad kidneys where the activity is 60 times higher than in the bladder. The serum specificity was verified by spot immunodetection, Western blot, inhibition capacity of antibodies, and immunoadsorption on a solid support with the renal enzyme. The sera were found to be able to react with native as well as denatured forms of the kidney enzyme. Antibodies cross-reacted with several peptides of low molecular weight (40-60 kDa) from urinary bladder plasma membrane proteins (Western blot).(ABSTRACT TRUNCATED AT 250 WORDS)     

Musculoskeletal Model of the Upper Limb Based on the Visible Human Male Dataset

A mathematical model of Ihe human upper limb was developed based on high-resolution medical images of the muscles and bones obtained from the Visible Human Male ( HM) project. Three-dimensional surfaces of the muscles and bones were reconstructed from Computed Tomography (CT) images and Color Cryosection images obtained from the VHM cadaver. Thirteen degrees of freedom were used to describe the orientations of seven bones in the model: clavicle, scapula, humerus, radius, ulna, carpal bones, and hand. All of the major articulations from the shoulder girdle down to the wrist were included in the model. The model was actuated by 42 muscle bundles, which represented the actions of 26 muscle groups in the upper limb. The paths of the muscles were modeled using a new approach called the Obstacle-set Method (33) The calculated paths of the muscles were verified by comparing the muscle moment arms computed in the model with the results of anatomical studies reported in the literature, In-vivo measurements of maximum isometric muscle torques developed at the shoulder, elbow, and wrist were also used to estimate the architectural properties of each musculotendon actuator in the model. The entire musculoskeletal model can be reconstructed using the data given in this paper, along with information presented in a companion paper which defines the kinematic structure of the model (26)     

Musculoskeletal model of the upper limb based on the visible human male dataset

A mathematical model of the human upper limb was developed based on high-resolution medical images of the muscles and bones obtained from the Visible Human Male (VHM) project. Three-dimensional surfaces of the muscles and bones were reconstructed from Computed Tomography (CT) images and Color Cryosection images obtained from the VHM cadaver. Thirteen degrees of freedom were used to describe the orientations of seven bones in the model: clavicle, scapula, humerus, radius, ulna, carpal bones, and hand. All of the major articulations from the shoulder girdle down to the wrist were included in the model. The model was actuated by 42 muscle bundles, which represented the actions of 26 muscle groups in the upper limb. The paths of the muscles were modeled using a new approach called the Obstacle-set Method [33]. The calculated paths of the muscles were verified by comparing the muscle moment arms computed in the model with the results of anatomical studies reported in the literature. In-vivo measurements of maximum isometric muscle torques developed at the shoulder, elbow, and wrist were also used to estimate the architectural properties of each musculotendon actuator in the model. The entire musculoskeletal model can be reconstructed using the data given in this paper, along with information presented in a companion paper which defines the kinematic structure of the model [26].     

Modelling slow wave activity in the small intestine

We have developed an anatomically based model to simulate slow wave activity in the small intestine. Geometric data for the human small intestine were obtained from the Visible Human project. These data were used to create a one-dimensional finite element mesh of the entire small intestine using an iterative fitting procedure. The electrically active components of the intestinal walls were modelled using a modified Fitzhugh-Nagumo cell model embedded within a longitudinal smooth muscle layer and a layer containing Interstitial Cells of Cajal. Within these layers, the monodomain equation was used to describe slow wave propagation. To solve the monodomain equation, a high-resolution finite difference grid, with an average spatial resolution of 0.95 mm, was embedded within each finite element. The resulting simulations of intestinal activity agree with the experimental observation that slow wave frequency gradually declines from 12 cycles per minute (cpm) in the duodenum to 8 cpm at the terminal ileum. Furthermore, the simulations demonstrated a decrease in conduction velocity with distance along the small intestine (10.7 cm/s in the duodenum, 5.1cm/s in the jejunum and 1.4 cm/s in the ileum), matching experimental recordings from the canine small intestine. We conclude that the framework presented here is capable of qualitatively simulating normal slow wave activity in an anatomical model of the small intestine.     

Source of a micro-nutrient in a semi-synthetic basal diet as a causative factor in inducing urinary calculi in rats and its inhibition by PSC 833, a potent inhibitor of P-glycoprotein

We report a serendipitous finding of urinary calculi in rats fed a semi-synthetic basal diet. This observation was made during ongoing studies to evaluate the inhibitory effect of PSC 833, a potent inhibitor of P-glycoprotein, on development of tumors in rodent tumor model systems. A large number of specific-pathogen-free (SPF) female Sprague-Dawley and SPF male Fischer 344 rats being fed the diet were euthanized when it became evident clinically that they were uremic. At necropsy, the renal pelvis, ureters, and urinary bladder contained numerous calculi. The presence of urinary calculi was determined to be related to the source of a Food Chemical Codex grade of choline bitartrate. Rats being fed the same basal diet containing the United States Pharmacopia grade of choline bitartrate failed to develop urinary calculi. Interestingly, rats treated with the P-glycoprotein inhibitor were at significantly reduced risk of developing urinary calculi. This finding highlights how something seemingly innocuous as a minor dietary constituent can have a profound impact and, thereby, affect experimental outcome.     

华鲮泌尿系统组织学的初步观察

2004年3月至9月采用常规组织学方法对华鲮泌尿系统作了研究,结果表明：华鲮泌尿系统包括中肾、输尿管、膀胱。中肾由肾小体和肾小管组成,无皮质、髓质之分,有肾小体聚集现象;肾小管可分为颈段、第一近曲小管、第二近曲小管、远曲小管、集合管。肾中散布有大量淋巴髓样组织,还有甲状腺滤泡和斯坦尼氏小体,显然华鲮的肾脏是一个具有多种生理功能的复合器官。输尿管位于两肾叶腹侧,其上皮为似复层,缺黏膜下层,无纵肌,外膜甚薄。左右输尿管在后端合并,稍微扩大,形成膀胱,膀胱内壁具有发达的绒毛,绒毛表面为变移上皮。     

A non-surgical rat model of foreign body-associated urinary tract infection with Pseudomonas aeruginosa

This study established a rat model of foreign body-associated urinary tract infection. A spiral polyethylene tube (PT) was placed transurethrally into the bladder without surgical manipulation, followed by transurethral inoculation with Pseudomonas aeruginosa. The persistence of P. aeruginosa in the kidneys and bladder was significantly enhanced by placement of the PT, whereas the bacteria were eliminated rapidly from the urinary tract in the animals without the PT. Scanning electron microscopy revealed a thick biofilm on the surface of the PT from the early stage of infection. Histopathologically, acute pyelonephritis was followed by chronic renal inflammation as well as continuous and sporadic polymorphonuclear leukocyte accumulation and hemorrhage in the pelvis and adjacent tissues, suggesting continuous ascending introduction of the bacteria from the biofilm adhering to the PT. We believe our model simulates the pathophysiology of foreign body-associated urinary tract infection characterized by biofilm formation on the surface of a foreign body.     

Urinary tract morphometry. An overview

An overview is presented of the application of morphometry to conditions in the urinary tract, with the work of a number of researchers briefly summarized. The data discussed show that morphometric techniques are already being successfully applied in the differential diagnosis and grading of some diseases of the prostate, urinary bladder and kidney. In the prostate, nonneoplastic changes can be differentiated from neoplasms and prostatic carcinomas can be more precisely graded. Both cytologic and histologic preparations of bladder carcinomas can be graded by morphometric techniques. Morphometry has found another application in assisting in the distinction between normal kidneys and those with "minimal-change" disease. The specific criteria pertaining to the use of morphometric methods in each of these situations are also discussed.