The mature epidermal cap is suspected to be a source of growth factors that stimulate the formation and maintenance of the function of the regenerating blastema
(a proliferative mass of pluripotent progenitor cells), as there is no regeneration in the absence of the epidermal cap (Goss, 1991).
Last but not least, the "theory of abnormal caudal rotation" proposes an explanation for renal ectopia, by stating that the lateral flexion and rotation of the caudal end of the embryo will thus alter the position of the blastema
, relative to the ureteric bud, rendering them crossed.
(52.) See Akulapalli, supra note 48 (reiterating lymph and blastema
theories of cancer).
It was previously speculated that the blastema
was comprised of a homogeneous population of multipotent cells (Figure 1(a)) that eventually form all the structures of the amputated digit tip or limb [26,27].
The tumour exhibited a triphasic pattern of blastema
, epithelium, and stroma with myxoid background in the solid area and in the septa of the cystic area.
While a limb blastema
can produce its own FGF-2, the scientists believe it needs an initial supply from nerves before it becomes self-sufficient.
El testiculo fetal se constituye mediante cuatro poblaciones celulares de distinto origen: celulas germinales primordiales, celulas del epitelio celomico, celulas provenientes de los conductos mesonefricos y celulas mesenquimales del blastema
gonadal (Rojas & Prieto, 2014).
In rats, the metanephric kidney develops at embryonic day 12, and this is followed by the ingrowth of the UB into the metanephric blastema
, inducing the metanephric mesenchymal stem cells (MMSCs) at the bud tips to condense around the UB tips.
Wilms' tumour also called as nephroblastoma is a malignant renal neoplasm of childhood that arises from remnant of immature kidney that is from abnormal proliferation of metanephric blastema
without differentiation into glomeruli and tubules.
This is thought to result from the abnormal development and migration of the ureteric bud and metanephric blastema
during the fourth week to eighth week of gestation.
(3,4) From a pathophysiology standpoint, horseshoe kidney occurs during the second and sixth week of gestation when the inferior portion of the metanephric blastema
fuses to form an isthmus, commonly in the lower renal pole (90%) and anteriorly to the aorta and vena cava.
(3) in 1979.The occurrence of the MURCS association is sporadic, (4) and the etiology is still not clear; one hypothesis is that it results from an alteration of the blastema
of the lower cervical and upper thoracic somites and pronephric ducts, which have an intimate spatial relationship in the fourth week of fetal development.