Effects of chronic restraint stress in the prostate of prepubertal and adult rats

Purpose: To investigate the effects of chronic stress in the prostate of prepubertal and adult rats. Methods: Thirty-two male rats were assigned into four groups depending on the type of treatment (control or stressed) and the age at which stress was initiated (prepubertal or adult). Restraint stress stimuli were applied for six weeks. Stressed prepubertal and adult rats evaluated immediately after the last stress stimuli were named SP and SA groups, respectively. Age-matched rats were used as control groups (CP and CA). At the end of the experiment, the rats were euthanized, and prostate morphological parameters were evaluated and statistically compared. Results: Application of stress stimuli to the SP group resulted in reduced body weight, but no prostate morphological modification was noted. The SA group showed reduced testosterone level and prostatic epithelium surface density, in comparison to CA group. Further, the prostatic lumen surface density was increased in adult stressed animals, in comparison to adult controls. Conclusions: The stress stimuli promoted changes in hormonal and morphological parameters in the prostate of adult stressed rats. Prepubertal stressed animals did not presented modifications of prostate morphology.

Quercetin as a nephroprotector after warm ischemia: histomorphometric evaluation in a rodent model

ABSTRACT Purpose: To quantitatively evaluate the possible long-term protective effects of quercetin during renal warm ischemia. Materials and Methods: Male rats were allocated into 4 groups: sham (S), sham quercetin (SQ), ischemia (I), and ischemia quercetin (IQ). Groups SQ and IQ received quercetin (50mg/kg) before and after surgery. Groups I and IQ had their left renal vessels clamped for 60 minutes. All animals were euthanized four weeks after the procedure, and serum urea and creatinine levels were measured. Renal weight and volume, cortex-non-cortex area ratio (C-NC), cortical volume (CV), glomerular volumetric density (Vv[glom]), volume-weighted glomerular volume (VWGV) and number of glomeruli per kidney (N[glom]) were evaluated by stereological methods. Results were considered statistically significant when p <0.05. Results: Serum urea levels in group I increased by 10.4% in relation to group S, but no differences were observed among the other groups. The C-NC of group I was lower than those of all other groups, and group IQ had similar results to sham groups. The Vv[glom] and N[glom] of group I were lower than those of group S (33.7% and 28.3%, respectively) and group IQ had no significant difference compared to the S group. Conclusions: Quercetin was effective as a nephroprotective agent in preventing the glomerular loss observed when the kidney was subjected to warm ischemia. This suggests that this flavonoid may be used preventively in kidney surgery, when warm ischemia is necessary, such as partial nephrectomy.

Effects of nandrolone decanoate on femur morphology. Experimental study

ABSTRACT Purpose To evaluate the immediate and late effects of nandrolone on femur morphology of rats. Methods Twenty-eight animals with 20 weeks of age were divided into four groups: C28, control animals that were euthanized eight weeks after the experiment started; C40, control animals euthanized 20 weeks after the experiment started; T28, treated animals receiving nandrolone during eight weeks and euthanized immediately after the treatment period; and T40, animals treated during eight weeks and euthanized 12 weeks after the end of the treatment. Treated animals received nandrolone decanoate during eight weeks and control groups received peanut oil by intramuscular injection. After euthanasia, femurs were removed, dissected, weighted and measured by digital pachymeter. Results The T40 group presented an increase on distal epiphysis diameter when compared to C40 group. There was no difference between treated and control groups in relation to body and femur absolute weight, relative weight and length of femur. There was also no difference in relation to diameter of proximal epiphysis and diameter of diaphysis among the groups. Conclusions Nandrolone decanoate does not produce significant effect on femur, exception on its distal extremity at late period. The effects of such drug may depend on the time after administration.

Does treatment with dutasteride or finasteride has impact on renal morphology? Experimental study

ABSTRACT Purpose: To investigate whether renal modifications occur following treatment with dutasteride or finasteride. Methods: Twenty-four male rats were divided into three groups: control (that received distilled water), dutasteride (0.5 mg/kg/day), and finasteride (5 mg/kg/day) groups. All administrations were given by gavage for 40 consecutive days. After inducing euthanasia, blood was collected for urea and creatinine analyses, and both the kidneys were collected for stereological analyses of kidney morphology. Results: Serum urea and creatinine levels were increased in both the finasteride and the dutasteride groups compared with those in the control group. In addition, kidney weight, kidney volume, cortical volume, glomerular volumetric density, and mean glomerular volume were reduced in both treatment groups. Finally, the number of glomeruli per kidney was reduced by 26.8% in the finasteride group and by 51.6% in the dutasteride group compared with that in the control group. Conclusions: The 5-ARIs finasteride and dutasteride promoted morphological and functional damages in rat kidneys. In addition, rats in the dutasteride group showed more severe renal modifications than those in the finasteride group.

Histomorphometric comparison of the corpus cavernosum of rats submitted to euthanasia with ketamine and xylazine or isoflurane

ABSTRACT Purpose: To compare the penile histoarchitecture of rats euthanized with isoflurane or with ketamine and xylazine. Methods: Fourteen male rats were divided into two groups: ISO, with animals euthanized with isoflurane; and K+X, with animals euthanized with ketamine (150 mg/kg) associated with xylazine (15 mg/kg). Immediately after the death, the penises were dissected, fixed in a 4% buffered formalin solution, and processed for histomorphometric analysis. The surface densities (Sv) of the corpus cavernosum structures (connective tissue, smooth muscle, sinusoidal space, and elastic fibers) were evaluated using Image J software. The distribution of collagen types I and III was qualitatively assessed. Statistical analyses were performed using the Student's t test for data comparison, considering it statistically significant when p < 0.05. Results: Regarding the Sv of connective tissue, smooth muscle and sinusoidal space, there were no differences between animals in both groups. On the other hand, the animals euthanized with the association of ketamine and xylazine showed the Sv of elastic fibers 24.8% higher in relation to animals euthanized with isoflurane. Conclusions: The euthanasia method affected one of the morphological parameters of the rat penises. The choice of euthanasia method must be standardized to reduce bias and to obtain reliable and reproducible results.

Different sample preparation methods for glomerular morphological evaluation: to coat or not to coat? / Diferentes métodos de preparación de muestras para la evaluación morfológica glomerular ¿recubrir o no recubrir?

The renal glomerulus is coated by fenestrated endothelial cells and externally covered by specialized epithelial cells, known as podocytes. Scanning electron microscopy becomes an important and effective tool for its studies. Normally, samples destined for scanning microscopy are covered with a thin metallic layer. However, this step can be dispensed for some analyzes. We aimed to compare coated and uncoated samples for evaluation of the glomerular morphology of the Wistar rat kidney. Cortical region of the kidney of the 5month-old male Wistar rats were used. The fragments followed the routine procedure for scanning electron microscopy processing. Half of 10 fragments were coated with palladium gold and the remaining were not coated. Auriga Compact FIB - SEM scanning electron microscope was used to observe the samples. Different increases and voltages was evaluated. For the uncoated samples, when using voltages of 2 KV (or higher) a great charging was observed, impairing the use of such voltage. Thus, these samples were always observed under voltage of 0.5 KV. On the other hand, in the coated samples, the use of 2 KV was adequate. Almost as a consequence, in the coated samples, the podocyte structures were better characterized, generating better images. Inversely, in the uncoated samples, it was possible to visualize the desired structures and to detect the morphological characteristics of these. The results showed that it is possible to use kidney samples without previous coating to evaluate the glomerular morphology at the ultrastructural level, serving as a tool in the study of pathologies.

El glomérulo renal está recubierto por células endoteliales fenestradas y cubierto externamente por células epiteliales especializadas, conocidas como podocitos. La microscopía electrónica de barrido se convierte en una herramienta importante y efectiva para sus estudios. Normalmente, las muestras destinadas a microscopía de barrido se cubren con una capa metálica delgada. Sin embargo, este paso se puede dispensar para algunos análisis. El objetivo fue comparar muestras recubiertas y no recubiertas para evaluar la morfología glomerular del riñón de rata Wistar. Se utilizó la región cortical del riñón de ratas Wistar macho de 5 meses de edad. Se realizó el procedimiento de rutina para el procesamiento de microscopía electrónica de barrido. La mitad de 10 fragmentos se recubrieron con oro paladio y los restantes no se recubrieron. Se utilizó un microscopio electrónico de barrido SEM Auriga Compact FIB para observar las muestras. Se evaluaron diferentes aumentos y voltajes. Para las muestras no recubiertas, al usar voltajes de 2 KV (o más) se observó una gran carga, impidiendo el uso de dicho voltaje. Por lo tanto, estas muestras siempre se observaron a bajo voltaje de 0,5 KV. Por otro lado, en las muestras recubiertas, el uso de 2 KV fue adecuado. Como consecuencia, en las muestras recubiertas, las estructuras de los podocitos se caracterizaron mejor, generando mejores imágenes. Inversamente, en las muestras no recubiertas, fue posible visualizar las estructuras deseadas y detectar las características morfológicas de éstas. Los resultados mostraron que es posible utilizar muestras de riñón sin recubrimiento previo para evaluar la morfología glomerular a nivel ultraestructural, que sirve como una herramienta en el estudio de patologías.

The relationship between renal warm ischemia time and glomerular loss. An experimental study in a pig model

Abstract Purpose: To investigate the glomerular number after different warm ischemia times. Methods: Thirty two pigs were assigned into four groups. Three groups (G10, G20, and G30) were treated with 10, 20, and 30 minutes of left renal warm ischemia. The sham group underwent the same surgery without renal ischemia. The animals were euthanized after 3 weeks, and the kidneys were collected. Right kidneys were used as controls. The kidney weight, volume, cortical-medullar ratio, glomerular volumetric density, volume-weighted mean glomerular volume, and the total number of glomeruli per kidney were obtained. Serum creatinine levels were assessed pre and postoperatively. Results: Serum creatinine levels did not differ among the groups. All parameters were similar for the sham, G10, and G20 groups upon comparison of the right and left organs. The G30 group pigs' left kidneys had lower weight, volume, and cortical-medullar ratio and 24.6% less glomeruli compared to the right kidney. A negative correlation was found between warm ischemia time and glomerular number. Conclusions: About one quarter of glomeruli was lost after 30 minutes of renal warm ischemia. No glomeruli loss was detected before 20 minutes of warm ischemia. However, progressive glomerular loss was associated with increasing warm ischemia time.

Glomerular loss after arteriovenous and arterial clamping for renal warm ischemia in a swine model

ABSTRACT PURPOSE: To evaluate the glomerular loss after arteriovenous or arterial warm ischemia in a swine model. METHODS: Twenty four pigs were divided into Group Sham (submitted to all surgical steps except the renal ischemia), Group AV (submitted to 30 minutes of warm ischemia by arteriovenous clamping of left kidney vessels), and Group A (submitted to 30 minutes of ischemia by arterial clamping). Right kidneys were used as controls. Weigh, volume, cortical volume, glomerular volumetric density (Vv[Glom]), volume-weighted glomerular volume (VWGV), and the total number of glomeruli were measured for each organ. RESULTS: Group AV showed a 24.5% reduction in its left kidney Vv[Glom] and a 25.4% reduction in the VWGV, when compared to the right kidney. Reductions were also observed when compared to kidneys of sham group. There was a reduction of 19.2% in the total number of glomeruli in AV kidneys. No difference was observed in any parameters analyzed on the left kidneys from group A. CONCLUSIONS: Renal warm ischemia of 30 minutes by arterial clamping did not caused significant glomerular damage, but arteriovenous clamping caused significant glomerular loss in a swine model. Clamping only the renal artery should be considered to minimize renal injury after partial nephrectomies.

Nutritional supplementation with arginine protects radiation-induced effects. An experimental study

ABSTRACT PURPOSE: To investigate the protective effect of L-arginine on the prostate (nonneoplasic) of rats with radiation-induced injury. METHODS: Twenty-nine Wistar rats, male adult, allocated into three groups: Control group (C) was not exposed to irradiation (n=10); Radiated group (R) had undergone pelvic irradiation (n=10); Supplemented and radiated group (R+S) had undergone pelvic irradiation plus L-arginine supplementation (n=9). The animals were observed for signs of toxicity. After euthanization, the prostate was dissected under magnification and stained by hematoxylin and eosin to study acinar structures and stained with Picrosirius red for collagen analysis. RESULTS: After radiation exposure, all animals presented diarrhea, but supplementation with L-arginine reduced this effect. The weight gain in the R+S group was significantly higher than in the C and R groups. In the R+S group the collagen density and the prostate acinar area was similar to the R and C groups. Epithelial height was significantly reduced in group R compared with group C (p<0.0001). When comparing the group R+S with R, a statistical difference was observed to be present (p<0.0001). CONCLUSIONS: Pelvic radiation promotes systemic effects and some structural modifications in the ventral prostate of rats. These modifications can be prevented by oral supplementation with L-arginine.

Laparoscopic correction of experimentally induced diaphragmatic rupture in dogs

PURPOSE:To describe the dog as a model for studying laparoscopic correction of experimental diaphragmatic ruptures.METHODS: Five male dogs were used in this study. Under laparoscopic approach, a defect of 7cm was created on the left ventral insertion of the diaphragm. Fourteen days after this procedure, the abdomen was explored using laparoscopic access and the diaphragmatic defect was corrected with intracorporeal suture. The dislocated organs, surgical time, and suturing time were recorded. Analgesia and clinical condition were monitored during the postoperative period.RESULTS:All animals recovered well from the diaphragmatic rupture creation. After 14 days, abdominal organs (liver, spleen, omentum and/or intestine) were found inside the thoracic cavity in all animals. It was possible to reposition the organs and suture the defect by laparoscopic access in three animals. These animals showed excellent postoperative recovery. It was not possible to reposition the liver safely when it was friable.CONCLUSIONS:Laparoscopic creation of diaphragmatic rupture in dogs is feasible. Dogs are a good model for training and studying the correction of experimentally created diaphragmatic rupture by the laparoscopic approach. A friable liver is a complicating factor that should be taken into account. Animals submitted to laparoscopic correction showed excellent postoperative recovery.

Morphometric study of the corpus cavernosum after anabolic androgenic steroid administration in pubertal and adult rats

PURPOSE: To evaluate the penile morphological modifications of pubertal and adult rats chronically treated with supra-physiological doses of anabolic androgenic steroids. METHODS: Forty-eight male Wistar rats were distributed into four groups: two control groups, 105- and 65-day-old (C105 and C65, respectively) injected with peanut oil (vehicle); and two treated groups, 105- and 65-day-old (T105 and T65, respectively) injected with nandrolone decanoate at a dose of 10 mg Kg-1 of body weight. The rats were injected once a week for eight weeks. The rats were then killed and their penises were processed for histomorphometric analyses. The mean of each parameter was statistically compared. RESULTS: A corpus cavernosum reduction of 12.5% and 10.9% was observed in the T105 and T65 groups, respectively, when compared with their respective control groups. The cavernosum smooth muscle surface density diminished by 5.6% and 12.9% in the T65 and T105 groups, respectively, when compared with their controls. In contrast, the sinusoidal space increased by 17% in the T105 group and decreased by 9.6% in the T65 group. CONCLUSION: The use of supra-physiological doses of AAS promotes structural changes in the rat penis, by altering the proportions of corpus cavernosum tissues, in both pubertal and adult treated animals. .

Experimental infection with the Toxoplasma gondii ME-49 strain in the Brazilian BR-1 mini pig is a suitable animal model for human toxoplasmosis

Toxoplasma gondii causes toxoplasmosis, a worldwide disease. Experimentation with pigs is necessary for the development of new therapeutic approaches to human diseases. BR-1 mini pigs were intramuscularly infected with T. gondii with tachyzoites (RH strain) or orally infected with cysts (ME-49 strain). Haematology and serum biochemistry were analysed and buffy coat cells were inoculated in mice to determine tachyzoite circulation. No alterations were observed in erythrocyte and platelet values; however, band neutrophils increased seven days after infection with ME-49. Serology of the mice inoculated with pig blood leucocytes revealed circulating ME-49 or RH strain tachyzoites in the pigs' peripheral blood at two and seven or nine days post-infection. The tachyzoites were also directly observed in blood smears from the infected pigs outside and inside leucocytes for longer periods. Alanine-aminotransferase was high at days 21 and 32 in the RH infected pigs. After 90 days, the pigs were euthanised and their tissue samples were processed and inoculated into mice. The mice serology revealed the presence of parasites in the hearts, ileums and mesenteric lymph nodes of the pigs. Additionally, cysts in the mice were only observed after pig heart tissue inoculation. The infected pigs presented similar human outcomes with relatively low pathogenicity and the BR-1 mini pig model infected with ME-49 is suitable to monitor experimental toxoplasmosis.

Scientific leaders for the future: primary and secondary education / Preparando lideranças científicas para o futuro: ensino médio e fundamental

Objective: To present a high school insertion pilot project in post graduate programs (PPG) and discuss the mechanisms for the formation of leaders in science. Methods: This study presents a review and pilot project. Bibliographic search occurred in sites of CAPES, MEC, SciELO and library of virtual books from January/ 2014 to February/2015. The pilot is in PPG-Medicine III Translational Surgery/UNIFESP and Pathophysiology and Surgical Sciences / UERJ. The junior undergraduate students (ICj) came from public school and develop scientific activities: scientific meetings, graduation and inclusion in research projects. The evaluation will occur at the end of one year, with the results essays, reports and participation in scientific events. Results: In Brazil, one of the main challenges of education is the high average years of study. The PNPG (2011-2020) shows the insertion of basic education in all PPG. In the Pathophysiology and Surgical Sciences/UERJ there are currently 11 high school students who have followed the scientific meetings and are being prepared for the inclusion in research projects. There was 30% of absence, owing to the high school hours. This result and the experience allow creating future alternatives to enhance the integration project. Conclusion: The leadership in science is formed from a complex relationship between basic education and investment in research. PPG-Medicine III courses follow the vanguard with initiatives focused on scientific and technological development. Thus, projects involving basic education students represent promoter model and environment leaders.

Objetivo: Apresentar um projeto piloto de inserção do ensino médio em programas de pós-graduação (PPG) e discutir os mecanismos para a formação de líderes em ciência. Métodos: Realizou-se um estudo de revisão e apresentação de piloto. A busca bibliográfica ocorreu nos sites da CAPES, MEC, Scielo e biblioteca de livros virtuais, de janeiro/2014 a fevereiro/2015. O piloto ocorre nos PPG-Medicina III em Cirurgia Translacional/UNIFESP e Fisiopatologia e Ciências Cirúrgicas/UERJ. Os alunos de iniciação científica júnior (ICj) são oriundos de escola pública e desenvolvem atividades científicas: participação em reuniões científicas, graduação e inserção nos projetos de pesquisa. A avaliação ocorrerá ao final de um ano, com redações dos resultados, relatórios e participações em eventos científicos. Resultados: No Brasil, um dos principais desafios da educação é a alta média de anos de estudo. O PNPG (2011-2020) apresenta a inserção da educação básica em todos os PPG. Na Fisiopatologia e Ciências Cirúrgicas/UERJ há atualmente 11 alunos do ensino médio, que já acompanharam as reuniões científicas e preparam-se para a inserção em projetos de pesquisa. Houve 30% de desistência, devido à alta carga horária escolar. Esse resultado e a experiência vivenciada permite criar alternativas futuras para aprimorar o projeto de inserção. Conclusão: A liderança em ciências é formada a partir de uma complexa relação entre educação básica e investimentos na pesquisa. Cursos de PPG-Medicina III seguem na vanguarda com iniciativas focadas no desenvolvimento científico e tecnológico. Assim, projetos envolvendo alunos da educação básica representam modelo e ambiente promotor de líderes.

The prostate after administration of anabolic androgenic steroids: a morphometrical study in rats

Purpose Many adverse effects have been associated with abuse of anabolic-androgenic steroids (AAS), including disorders of the urogenital tract. The objective of this study is to analyze the morphological modifications in the prostate ventral lobe of pubertal and adult rats chronically treated with AAS, using morphometric methods. Materials and Methods: We studied 39 male Wistar rats weighing between 400 g and 550 g. The rats were divided into four groups: (a) control rats, with 105 days of age (C105) (n = 7); (b) control rats with 65 days of age (C65) (n = 9), injected only with the vehicle (peanut oil); (c) treated rats, with 105 days of age (T105) (n = 10) and (d) treated rats with 65 days of age (T65) (n = 13). The treated rats were injected with nandrolone decanoate at a dose of 10 mg.Kg-1 body weight. The steroid hormone and the vehicle were administered by intramuscular injection once a week for eight weeks. The rats were killed at 161 days of age (C105 and T105) and 121 days of age (C65 and T65) and the ventral prostate lobe was dissected and processed for histology. The height of the acinar epithelium, the surface densities of the lumen, epithelium and stroma were observed with X400 magnification using an Olympus light microscope coupled to a Sony CCD video camera, and the images transferred to a Sony monitor KX14-CP1. The selected histological areas were then quantified using the M42 test-grid system on the digitized fields. The data were analyzed with the Graphpad software. To compare the quantitative data in both groups (controls and treated) and the outcomes, Student's t-test was used (p < 0.05 was considered significant). Results: The weight (p < 0.001) and volume (p = 0.004) of the prostate ventral lobe showed differences between C65 and T65 groups and between C105 and T105 groups. The epithelium height showed no difference between groups C65 and T65 (p = 0.8509), but the T105 group showed an increase of 32% compared ...

Cicatrização renal após nefrectomia parcial laparoscópica sem fechamento do sistema coletor em porcos / Kidney healing after laparoscopic partial nephrectomy without collecting system closure in pigs

Introdução: Embora alguns estudos tenham descrito as semelhanças e diferenças anatômicas entre o rim humano e o rim suíno, pouco é conhecido sobre a cicatrização renal neste animal. O conhecimento da cicatrização do rim do porco é especialmente importante em procedimentos cirúrgicos que incisem o tecido renal e o sistema coletor, como é o caso da nefrectomia parcial. O objetivo do presente trabalho é estudar a cicatrização renal em porcos após nefrectomia parcial laparoscópica sem o fechamento do sistema coletor. Materiais e Métodos: Quatorze porcos machos com peso médio de 30 kg foram submetidos à nefrectomia parcial laparoscópica esquerda, removendo 25% do comprimento renal no pólo caudal (n=7) ou no pólo cranial (n=7). A técnica cirúrgica empregada envolveu acesso laparoscópico transperitoneal, clampeamento em bloco dos vasos renais, excisão do tecido renal com tesoura a frio e aplicação de energia monopolar para hemostasia do parênquima, deixando o sistema coletor aberto. Os animais foram avaliados clinicamente por 14 dias e então foram mortos. Níveis séricos de creatinina e uréia foram obtidos antes e em diferentes momentos após a cirurgia. São relatados ainda os achados de necropsia, pielografia retrógrada ex vivo e aspectos histológicos dos pólos renais operados. Resultados: Os níveis séricos de uréia e creatinina tiveram leve aumento inicial retornando aos valores pré-operatórios durante o período avaliado. Durante a necropsia verificou-se que não houve extravasamento de urina a partir do rim operado e que este se cobriu com tecido fibroso, aderindo-se aos tecidos adjacentes. Nas pielografias retrógradas não foi verificado nenhum extravasamento de contraste pelos pólos operados. Os achados histológicos mostraram grande deposição de colágeno tipo I sobre o pólo renal operado, vedando-o completamente. Conclusão: O rim suíno não é um bom modelo para pesquisas ou treinamento cirúrgico em que a cicatrização do sistema coletor seja um aspecto importante.

Introduction: Although some studies have described similarities and diferences between human and pig kidney anatomy, little is known regarding renal healing in this animal model. The knowledge of pig kidney healing is especially important in surgical procedures which incise the renal parenchyma and collecting system, such as partial nephrectomy. The aim of this study is to access kidney in pigs after laparoscopic partial nephrectomy without closuring of the collecting system. Materials and Methods: Fourteen male pigs with mean weight of 30 kg were submitted to left partial laparoscopic nephrectomy, removing 25% of the kidney length at caudal pole (n=7) or at cranial pole (n=7). Briefly, the surgical technique involved a transperitoneal laparoscopic access, en bloc vascular clamping of renal artery an vein, tissue excision with cold scissor and monopolar energy parenchyma hemostasis, leaving the collecting system opened. The animals were clinically evaluated during fourteen days, and afterwards were killed. Serum levels of creatinine and urea were assessed prior and at different moments after surgery. Necropsy findings, retrograde ex vivo pyelogram and histological aspects of operated renal poles are also described. Results: Serum creatinine and urea showed a slight initial increase with a gradual return to preoperative levels during the evaluated period. At necropsy, no signs of urine leakage were found and kidneys were covered by a fibrous tissue with adherences to adjacent organs. Also, in the retrograde pyelograms obtained, we did not find contrast medium leakage by operated poles. Histological findings showed great deposition of type I collagen over operated renal pole, sealing it completely. Conclusion: The pig kidney is not an adequate experimental model for research and training of surgery on which collecting system healing is an important aspect to be considered.