A double fluorescence chimeric limb regeneration model reveals muscle fiber reconnection during axolotl limb regeneration / Modelo de regeneración quimérica de doble fluorescencia del miembro revela la reconexión de la fibra muscular durante la regeneración del miembro axolotl

SUMMARY: Axolotl limb regeneration is a fascinating characteristic that has attracted attention for several decades. Our previous studies on axolotl limb regeneration indicated that the satellite cells in the remnant muscles move distally into the blastema to regenerate new muscles that are separated by a gap from remnant muscles. Thereafter, the regenerative muscle fibers start to reconnect with remnant ones. In this study, the reconnection at the individual muscle fiber level was elucidated to test the hypothesis that this reconnection happens synchronously among involved muscles. Three pairs of EGFP+ mid-bud stage blastemas were transplanted onto freshly amputated stumps of RFP+ axolotls at the same thigh position to generate double fluorescence chimeric regenerative hindlimbs. These regenerative limbs were harvested very late far beyond they had reached the late differentiation stage. Fluorescence imaging of these limbs in cross sections revealed that in the proximal remnant part of the muscle fiber, reconnection occurred at a different pace among the muscles. In the major thigh muscle gracilis, the reconnection started from the periphery before it was completed. Furthermore, RFP+ muscle fibers contributed to muscle regeneration in the distal regenerative parts. Intriguingly, this red cell contribution was limited to ventral superficial muscles of the calf. This kind of double fluorescence chimeric limb regeneration model may help increase the understanding of the patterning of axolotl limb regeneration in late stages.

RESUMEN: La regeneración del miembro de Axolotl es una característica fascinante que ha llamado la atención durante varias décadas. Nuestros estudios previos sobre la regeneración del miembro del Axolotl indicaron que las células satélite en los músculos remanentes se mueven distalmente hacia el blastema para regenerar nuevos músculos que están separados por una brecha de músculos remanentes. A partir de entonces, las fibras musculares regenerativas comienzan a reconectarse con las restantes. En este estudio, se aclaró la reconexión a nivel de fibra muscular individual para probar la hipótesis de que esta reconexión ocurre sincrónicamente entre los músculos involucrados. Se trasplantaron tres pares de blastemas EGFP+ en la etapa de yema media en tocones recién amputados de axolotls RFP+ en la misma posición del muslo para generar miembros posteriores regenerativos quiméricos de fluorescencia doble. Estos miembros regenerativos se cosecharon muy tarde mucho más allá de haber alcanzado la etapa de diferenciación tardía. Las imágenes de fluorescencia de estos miembros en secciones transversales revelaron que en la parte remanente proximal de la fibra muscular, la reconexión se produjo a un ritmo diferente entre los músculos. En el músculo grácil, la reconexión comenzó desde la periferia antes de completarse. Además, las fibras musculares RFP+ contribuyeron a la regeneración muscular en las partes regenerativas distales. Curiosamente, esta contribución de glóbulos rojos se limitó a los músculos superficiales ventrales de la pantorrilla. Este tipo de modelo de regeneración quimérica de doble fluorescencia del miembro puede ayudar a aumentar la comprensión del patrón de la regeneración del miembro del Axolotl en etapas tardías.

Relationship between cellular rejection and development of rat transplanted metanephroi from different gestational ages / 中华器官移植杂志

Objective To explore the relationship between cellular rejection and the development of allo-or xenografted primordia from different gestational ages .Methods Whole rat metanephroi from embryonic day E14～ E19 were transplanted into omenta of outbred (SD → SD ,6 groups ,n≥10 each ;E15-E17SDCsA ,3 groups ,n=15 each) ,syngeneic (Lewis→Lewis ,5 groups ,n=8 each) ,allogeneic (Lewis→BN ,E15BN n= 6 each E15BNCsA n= 10 each ,E16BNCsA n= 10 each) rats and xenogeneic (Lewis→C57groups ,E15C57 n=10 each ,E15C57CsA ,n=8 each ;Lewis→Balb/c nude mice ,3 groups ,n=10 each) recipients .Histopathology ,Banff's grading and electron microscopy (EM ) were utilized for assessing the graft development .Similarly ,biochemical indicators and creatinine clearances were measured .Results At 4 weeks post-transplantation , in SD → SD groups ,E14-E17SD metanephroi developed with Banff ' s rejections . E14/E15SD was significantly lighter than E16/E17SD ( P< 0 .01 );E18/E19SD barely developed . After cyclosporine A (CsA , 8 mg·kg -1·d-1 )dosing ,Banff's rejection of E15-E17SDCsA group lessened significantly .In Lewis→BN ,E15BN metanephroi were completely rejected .After dosing CsA (12 mg·kg -1·d-1 ) ,E15BNCsA and E16BNCsA Banff ' s rejections became alleviated . Upon a discontinuation of CsA , both metanephroi were rejected . In Lewis → Lewis , E15 ～ E17Lewis metanephroi developed well . No significant difference existed in Banff's classification (P>0 .05) .E14Lewis and E18Lewis rats had significantly poorly differentiated metanephroi than those in E16 Lewis group .In Lewis→C57BL/6 , E15 metanephroi were rejected at Day 14 post-transplantation (n= 10) and no improvement was evident after CsA dosing (15 mg·kg -1·d-1 ,n=8) .In Lewis→Balb/c nude mice ,all E15～E17Balb/c metanephroi developed well .Both light microscopy and EM examination showed normal nephrons and collecting ducts and wet weight ,creatinine or urea nitrogen of effusion showed no significant difference (P>0 .05) .E15Lewis and E16Lewis had significantly different values of wet weight and creatinine clearances from those of E15SDCsA and E16SDCsA .E15SDCsA had the greatest wet weight and the lowest creatinine clearance rate (P< 0 .01) .Conclusions After controlling rejection during allo-and xenotransplantations ,E15 ,E16 and E17 rat metanephros have similar development characteristics . And cellular immunogenic factors still remain the major barriers to their developments .

A comparative study of fixatives for axolotl blastema tissue / Estudio comparativo de fijadores para el tejido blastema del axolotl

Regeneration is defined as tissue renewal and functional restoration process of the damaged parts of the body after an injury. Ambystoma mexicanum, commonly named the Axolotl, is one of the unique vertebrates, which has a remarkable ability to regenerate their extremities following the amputation. Although the process of regeneration includes several periods, it can be divided into two main phases; blastema formation and dedifferentiation. In the couple of hours following the amputation, wound closure occurs by migration of epithelial cells around the amputation site followed by macrophage infiltration and dedifferentiation of cells to turn into stem cells. Accumulated stem cells form a very authentic tissue type called blastema, which is crucial for successful regeneration. In order to evaluate this exceptional tissue and acquire high quality images, it is crucial to employ specific procedures to prepare the tissue for imaging. Here, in this study, we aimed to investigate success of various fixative solutions (Carnoy's, Bouin's, % 10 NBF, Clarke's, Alcoholic Formaline and AFA) to monitor the fixed blastema. Our data reveals that integrity of the blastema tissue differs among used fixatives and a significant difference is observed between the samples in terms of staining quality.

La regeneración se define como la renovación del tejido y el proceso de restauración funcional de las partes dañadas del cuerpo después de una lesión. Ambystoma mexicanum, comúnmente llamado Axolotl, es uno de los únicos vertebrados que tiene una notable capacidad para regenerar sus miembros después de una amputación. Aunque el proceso de regeneración incluye varios períodos, se puede dividir en dos fases principales: formación del blastema y desdiferenciación. En el par de horas después de la amputación, el cierre de la herida ocurre por la migración de células epiteliales alrededor del sitio de la amputación seguido por una infiltración de macrófagos y la desdiferenciación de las células para convertirse en células madre. Las células madre acumuladas forman un tipo de tejido muy diferenciado denominado blastema, que es crucial para una exitosa regeneración. Para evaluar este tejido y adquirir imágenes de alta calidad, es crucial emplear procedimientos específicos para la obtención de imágenes. En este estudio, se intentó investigar el éxito de varias soluciones fijadoras (Carnoy, Bouin, % 10 NBF, Clarke, Formalina Alcohólica y AFA) para monitorear la fijación del blastema. Nuestros datos revelan que la integridad del tejido del blastema difiere entre los fijadores utilizados y una diferencia significativa observada entre las muestras se da en términos de la calidad de tinción.

Planarians: an In Vivo Model for Regenerative Medicine

The emergence of regenerative medicine has raised the hope of treating an extraordinary range of disease and serious injuries. Understanding the processes of cell proliferation, differentiation and pattern formation in regenerative organisms could help find ways to enhance the poor regenerative abilities shown by many other animals, including humans. Recently, planarians have emerged as an attractive model in which to study regeneration. These animals are considering as in vivo plate, during which we can study the behavior and characristics of stem cells in their own niche. A variety of characteristic such as: simplicity, easy to manipulate experimentally, the existence of more than 100 years of literature, makes these animals an extraordinary model for regenerative medicine researches. Among planarians free-living freshwater hermaphrodite Schmidtea mediterranea has emerged as a suitable model system because it displays robust regenerative properties and, unlike most other planarians, it is a stable diploid with a genome size of about 4.8x108 base pairs, nearly half that of other common planarians. Planarian regeneration involves two highly flexible systems: pluripotent neoblasts that can generate any new cell type and muscle cells that provide positional instructions for the regeneration of anybody region. neoblasts represent roughly 25~30 percent of all planarian cells and are scattered broadly through the parenchyma, being absent only from the animal head tips and the pharynx. Two models for neo-blast specification have been proposed; the naive model posits that all neoblasts are stem cells with the same potential and are a largely homogeneous population.

Horseshoe kidney: a case report.

The horseshoe kidney was originally regarded as a rare anatomical curiosity, but with the aid of retrograde pyelogram, intravenous urogram and renal arteriograms in this present age of diagnosis, the incidence of horseshoe kidney is estimated at 1 in 200-400 individuals or 1 in 700 autopsies and usually remains asymptomatic. The present report is concerned with a case of horseshoe kidney, which was observed during routine cadaveric dissection, for student education in anatomy dissection hall of Osmania medical college, in a male cadaver. The kidneys formed a U-shaped structure as a result of fusion at the inferior poles of the original kidneys by a parenchymatous isthmus. As a whole, the structure presented a typical horseshoe shape. The location of the kidney was lower than that of the normal kidney. The renal arterial system was almost normal except for a surplus artery into the isthmus that directly originated from the aorta, at the origin of inferior mesenteric artery. Venous drainage of both the kidneys and the isthmus was through two veins which opened independently into the inferior vena cava. The hila on both sides opened towards the ventral direction, and the ureters descended in front of the isthmus and entered the bladder normally. This report is being made because it affords material for a review of embryological and gross anatomy findings in a case of horseshoe kidney, which could help in a thorough urologic evaluation in diagnosed cases prior to any surgical intervention.

A Case of Horseshoe Kidney / 체질인류학회지

During cadaver dissection at Chungnam National University in year 2001, we found a case of horseshoe kidney. The characteristic findings of this kidney were as follows; 1. Horseshoe kidney was located at the level of 12th thoracic vertebra and 4th lumbar vertebra, and its isthmus was located at the level of 3rd lumbar vertebra, just below inferior mesenteric artery. The upper pole of the right kidney was 11 mm higherthan that of left kidney. 2. Both renal arteries originated normally from the abdominal aorta below superior mesenteric artery and divided into 2 branches at the front of the renal hilum. The lower branches entered normally into the renal hilum respectively, but, 2 upper branches of right renal artery and 3 upper branches of left renal artery entered into the upper segment of both kidneys respectively. 3. The 2 accessory renal arteries were found. One was the branch of the median sacral artery, which asended anterior to the bifurcation of abdominal aorta and divided 2 branches, of which larger right branch entered inferior pole of right kidney and smaller left branch entered into the isthmus. The other was originated from abdominal aorta 1/3 distance from the origin of inferior mesenteric artery to the bifurcation of abdominal aorta, and entered into the posteroinferior part of left kidney. 4. There were additional 2~3 minor calyces in the lower part of the both kidneys in frontal section, which formed a major calyx draining into the renal pelvis. Parenchymal tissues of both kidneys were continuous through isthmus. In frontal section, renal pyramids were twice in number, and arranged into 2 groups at the upper and lower parts of the both kidneys. Especially, one renal pyramid laid transversely in the isthmus and the renal papilla of it opened into the minor calys of left kidney. It is thought that this horseshoe kidney might be resulted from the elongation of a ureteric bud, which induced new broad -field nephron within the metanephric blastema, and formed a group of additional renal pyramids. The additional renal pyramids formed slight later than normal period, and the separation of both kidneys should be failed and resulted horseshoe kidney. During ascent of kidney, the inferior mesenteric artery interrupted upward migration. It can be concluded that the error of reciprocal induction between ureteric bud and metanephric mesenchyme may be an important mechanism of horseshoe kidney formation.

Multilocular Cyst of the Kidney with Mature Renal Element in Fibrous Septa / 대한비뇨기과학회지

Multilocular renal cyst is an uncommon lesion which has various terminologies and controversial criteria of definition. Recently, it is said that these can be divided into cystic nephroma(CN) and cystic partially differentiated nephroblastoma(CPDN) based on the presence or absence of blastemal tissue and differentiation of the tissue within the septa of the cyst. We experienced a case of multilocular renal cyst(CN) which contains mature tubular and glomerular structures in the septa without evidence of blastema or embryonal elements and we are going to discuss the significance of this blastemal or embryonal tissue with regard to nature, classification, and prognosis with literatures.