Actuotaphonomic model of the mollusk fauna of Laguna de Mandinga, Veracruz, Mexico / Modelo actuotafonómico de la fauna de moluscos de Laguna de Mandinga, Veracruz, México

Introduction: The taphonomic attributes of a faunal assemblage provide information about which agents affect the distribution and preservation of ancient or newly formed biogenic materials during depositional and post-depositional processes. Actuotaphonomy thus is a valuable tool for reconstructing fossil communities because it establishes analogies between observable processes in the present and those that happened in the past. Objective: The taphonomic attributes of a marginal marine environment were analyzed to assess the origin of fragmentation, bioerosion, and encrustation processes and the role of these characteristics in the deterioration of current sediment accumulations of mollusks (gastropods and bivalves). Methods: The material studied was collected from a shell-remain accumulation called "El Conchal" in the Laguna de Mandinga, Veracruz, a lagoonal complex located in the Gulf of México. Taphonomic analysis included fragmentation, bioerosion, and encrustation features on recent gastropods and bivalve's shells. The categories of each attribute were classified in three degrees: poor, regular and good. The analysis was performed only in complete shells. Results: A bulk sample of 1 697.9 g was processed, recovering 1 165 complete specimens, of which 5 genera of bivalves and 4 genera of gastropods were identified. The fragmentation and bioerosion were classified as regular (grade 1), this may be the results of the water energy in the environment, that permits a constant rework, and exhumation of the remains at the lagoon's water-sediment interface; meanwhile, three eroders were identified to ichnogenus level: Entobia, Oichnus, and Caulostrepsis, being Caulostrepsis the least abundant. The encrustation was classified as poor (grade 2); the result can be interpreted based on the ecosystem intrinsic conditions that do not allow many encrusting organisms to develop properly. The encrusters are represented by calcareous organisms including bryozoans, serpulids tubes, and barnacles. The results yielded an actuotaphonomic model that could be applicable to analogous ecosystems in Laguna de Mandinga (Mandinga Lagoon), in Veracruz, Mexico. Conclusions: In marine marginal environments as in lagoon areas the encrustation does not have an important role in the preservation or destruction of shelly assemblages, being taphonomically more important than fragmentation and bioerosion as potentially destructive agents that can be a source of loss of fidelity in the fossil record.

Introducción: Los atributos tafonómicos de los conchales proveen información acerca de cuáles agentes afectan la distribución y preservación de la acumulación de materiales biogénicos recientes o fósiles, especialmente durante las etapas deposiconales y postdeposicionales. La actuotafonomía es una herramienta valiosa para la reconstrucción de las comunidades fósiles, para establecer analogías entre los procesos observables en el presente con los que ocurrieron en el pasado. Objetivos: Evaluar el impacto de los rasgos tafonómicos y su papel en la formación de los conchales en ambientes de lagunas costeras. Métodos: El material estudiado fue recolectado en una acumulación de restos de conchas llamado "El Conchal" en la Laguna de Mandinga, Veracruz, un complejo lagunar ubicado en el Golfo de México. El análisis tafonómico incluye las características tafonómicas de fragmentación, bioerosión e incrustación en conchas de gasterópodos y bivalvos recientes. Las categorías de cada atributo se clasificaron en tres grados: pobre, medio y alto. El análisis fue realizado solo en conchas completas. Resultados: Se procesaron 1 697.9 g de sedimentos, recuperando 1 165 ejemplares completos, de los cuales se identificaron 5 géneros de bivalvos y 4 géneros de gasterópodos. La fragmentación y bioerosión se clasificaron como un "grado regular", esto puede ser el resultado de la energía del agua en el ambiente, que permite el constante retrabajo y la exhumación de los restos en la interfase agua-sedimento en la laguna; en tanto que, se identificaron tres erosionadores a nivel de género, estos corresponden a los icnogéneros: Entobia, Oichnus y Caulostrepsis, siendo Caulostrepsis el menos abundante. La incrustación mostró un "grado pobre"; el resultado puede interpretarse basado en las condiciones intrínsecas del ecosistema que no permiten que muchos incrustantes se desarrollen de la manera adecuada. Los incrustantes están representados por organismos calcáreos incluyendo briozoarios, tubos de serpúlidos y balanos. Se analizaron los atributos tafonómicos para generar un modelo actuotafonómico que pueda ser aplicable a ecosistemas análogos en el registro fósil. Conclusiones: En ambientes marino marginales como son las áreas lagunares la incrustación no tiene un papel importante en la preservación o destrucción de los conchales, siendo tafonómicamente más importante la fragmentación y bioerosión como agentes potencialmente destructivos que pueden ser un recurso de pérdida de la fidelidad en el registro fósil.

Management of forgotten double-J stent in a tertiary care center with ten years of experience: a retrospective study

Background: Forgotten double-J (DJ) stents is documented commonly in urological cases with consequences varying from encrustation, UTIs, pyelonephritis, hydronephrosis and non-functioning kidney. This study aimed to present the experience of managing patients with forgotten DJ stents (>3 months) over a period of ten years.Methods: The study conducted a retrospective review of patients with forgotten DJ stents from January 2009 to December 2019. The details reviewed included indications for stent placement, indwelling time, presenting complaints, reason for non removal, radiological investigations, management techniques, and complications.Results: 52 patients with forgotten DJ stents for >3 months were reviewed. Mean age was 32.1 years. The majority were literate (73.1%). Ureteroscopy was the most common primary surgery performed (53.8%). The mean indwelling time was 38.96 months. Presence of the ureteric stone, bladder stone, and renal stone was observed in 45 (86.5%), 42 (80.7%), and 28 (53.8%) patients, respectively. The DJ stent was fragmented in 13.4% of the patients. The commonest complaints were pain (88.4%) and dysuria (63.4%). The stents were managed by combinations of various endourological techniques including cystoscopic stent retrieval (CPE), PCNL, URSL, ESWL with cystoscopic stent retrieval, PCLT (percutaneous cystolithotripsy). Cystolithotomy was used for very large bladder stones. Nephrectomy was needed in 2 cases due to nonfunctional kidneys while one required open ureterolithotomy and stent retrieval after failure of endoscopic approach.Conclusions: Forgotten DJ stents have severe consequences and management approach requires combination of various endourological procedures with ESWL, URSL, PCNL, open ureterolithotomy and cystolithotripsy.

Feasibility of minimally invasive management in patients with forgotten double J stent: a single centre experience

Background: aim of the study was to present the experience in managing forgotten/encrusted Double J (DJ) ureteral stents and to review the literature on the subject.Methods: Author retrospectively studied patients presenting to the Outpatient Department from January 2016 to January 2019 with forgotten DJ stent(s) (six or more than six months after the insertion). Data was collected for age, gender, indication for DJ stenting, clinical features at presentation, radiological imaging and surgical procedure performed to extract the DJ stents. The post-operative stay, complications of the procedures and morbidity was also studied.Results: During the study period, a total 32 patients reported to the department with history of forgotten DJ stents. Most common age group involved was 41-60 years. Most common presenting symptoms were lower urinary tract symptoms (LUTS) or dysuria.  Duration of stent in-situ ranged from 6 month to 15 years. Most common sites of encrustations along the forgotten DJ stent were ureter and kidney followed by urinary blabber. Fluoroscopic guided DJ stent removal was done in 8 patients. A combination of Cystolithotripsy, URSL and PCNL was needed to clear the stone and extract the DJ stent in remaining patients.Conclusions: Forgotten/encrusted DJ stent may lead to complications ranging from urinary tract infections to loss of renal function. They can be safely and successfully removed, and the renal function can be preserved. Endo-urological management of forgotten encrusted stents is highly successful and often avoids the need for open surgical techniques.

An Unusual Case of Retained DJ Stent

Double J stents are an integral part of urological practice today. Ureteral stenting is done as an adjunct to ureteral surgery and for managing ureteral obstruction. Every urological surgery doesn't require DJ stenting and their use must be strictly restricted to selected cases. Retension is a common complication of ureteral stents and is mostly due to encrustations on a forgotten DJ stent. Here we report a case of retained DJ stent which was placed during open nephrolithotomy. It was neither forgotten nor encrusted, but was embedded in the renal parenchyma. As per our knowledge this is the first case of its kind to be reported in medical literature.

Effect of pneumatic lithotripsy treatment under ureteroscopic on urinary catheter encrustation / 中国综合临床

Objective To evaluate the therapy effect of pneumatic lithotripsy treatment under ureteroscopic on urinary catheter encrustation(CE).Methods Eight patients with difficulty in pulling catheter tube crustcaused were enrolled as our subjects.They were performed pneumatic lithotripsy under ureteroscope operation.The information related to operation was recorded.Results Eight cases were successful in terms of crushing catheter encrustations,and the catheters were removed smoothly.Conclusion The therapy of pneumatic lithotripsy treatment under ureteroscopic is proved to be a minimally invasive treatment with small damage,and higher safety.

Formação de biofilme cristalinode Proteus mirabilis em cateterurológico / Formation of crystalline biofilm of Proteus mirabilis in urological catheter

O cateter uretral de longa permanência tem papel de destaque para pacientes com retenção urinária, com obstrução debexiga, com danos neurológicos e outras doenças. A urina contém sais minerais, que em pH alcalino se precipitam,cristalizam-se e bloqueiam o cateter urológico. A cristalização dos componentes iônicos da urina ocorre em presença de urease, enzima produzida por Proteus mirabilis. Esta bactéria tem a capacidade de aderir a superfícies inanimadas e formar biofilme. O objetivo deste estudo foi observar a formação de biofilme cristalino na superfície luminal de cateter urológicode látex siliconizado, por meio de microscópio eletrônico de varredura, após a canalização de urina artificial infectada com Proteus mirabilis. O experimento foi realizado in vitro,em sistema de fluxo dinâmico. A urina artificial, composta de sais de cálcio, magnésio, fosfatos, uréia e albumina deovo, foi infectada com Proteus mirabilis ATCC 25933. O fluxo da urina canalizada foi interrompido após a cristalização dos componentes iônicos. A cristalização foi observada após a alcalinização da urina. A microscopia eletrônica de varredura demonstrou a presença de cristais e morfologiastípicas de bacilos embutidos em massa amorfa. O presente estudo mostrou que a incrustação pode limitar o uso decateter urológico de longa permanência.

The indwelling urethral catheter has an important role for patients with urinary retention, bladder obstruction, neurological damage and other diseases. Urine contains minerals which precipitate in alkaline pH, crystallize and block the urological catheter. Thecrystallization of the ionic components of urine occurs in the presence of urease, an enzyme produced by Proteus mirabilis. This bacterium adheres to inanimate surfaces and forms biofilms. The aim of this study was to investigate the formation of crystalline biofilm on the luminal surface of siliconized latex catheters by means of scanning electron microscope, after channeling artificialurine infected with Proteus mirabilis. The experiment was performed in vitro using a dynamic flow system. The artificial urine compounds were salts of calcium, magnesium, phosphates, urea and egg albumin, and it was infected with Proteus mirabilis ATCC 25933. The urine flow was stopped after crystallization of the ionic components. Crystallization was observed afteralkalinization of urine. Scanning electron microscopy showed the presence of crystals and morphologies typical of bacilli embedded in an amorphous mass on the internal lumen of the catheter. Thepresent study showed that catheter encrustation may limit the use of long-term indwelling catheter.