The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
Tomas Soukup - One of the best experts on this subject based on the ideXlab platform.
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slow to fast muscle transformation following heterochronous Isotransplantation is influenced by host thyroid hormone status
Histochemistry and Cell Biology, 2014Co-Authors: Kateřina Kopecka, Gisela Zacharova, Vika Smerdu, Tomas SoukupAbstract:We studied the effect of regeneration, altered innervation and thyroid hormone (TH) levels on fiber type transitions in slow soleus (SOL) muscles grafted (GRAFT) into host extensor digitorum longus (EDLh) muscles of euthyroid (EU), hyperthyroid (HT) and hypothyroid (HY) Lewis strain rats. SOL muscles were excised from 3-week to 4-week-old inbred Lewis rats and intramuscularly transplanted into EDLh muscles of 2-month-old female rats of the same strain. The proportions of type 1, 2A, 2X and 2B fibers of GRAFT were determined by immunohistochemistry and compared with those of EDLh muscle and EDL and SOL muscles of the unoperated contralateral hind limb. After an average regeneration period of 6-7 months and after being reinnervated by the "fast" peroneal nerve of EDLh muscle, GRAFT was transformed into a fast muscle. However, the extent of GRAFT transformation varied with different TH states. In the EU rats, GRAFT contained about 95 % of fast fibers, among which type 2X and 2B fibers predominated (about 75 %). The transition toward fast muscle phenotype was more pronounced in HT status, where the fastest type 2B fibers predominated. On the contrary, in HY status, the slow to fast transformation was less pronounced, as GRAFT contained less type 2B and 2X but more type 2A and 1 fibers. We conclude that the type of innervation is the crucial factor for the slow to fast fiber type transitions in GRAFT, but the extent of muscle transformation is further modulated by altered TH status.
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fiber type composition of unoperated rat soleus and extensor digitorum longus muscles after unilateral Isotransplantation of a foreign muscle in long term experiments
Physiological Research, 2009Co-Authors: Tomas Soukup, Vika Smerdu, G ZachařovaAbstract:Summary We examined the effects of the unilateral heterochronous Isotransplantation on the fiber type composition and myosin heavy chain (MyHC) isoform content of unoperated slow soleus and fast extensor digitorum longus muscles of female inbred Lewis strain rats. Comparison was made between “control” unoperated muscles of experimental rats (after intramuscular transplantation surgery) with the corresponding muscles of completely naive (unoperated) rats of three age groups (5-, 8and 14-month-old). This was done in order to ascertain whether these muscles can be used as reliable controls to the transplanted and host muscles for our ongoing grafting experiments. The fiber type composition was determined by assessing the histochemical reaction for myofibrillar adenosine triphosphatase, the MyHC isoform content was determined immunocytochemically using monoclonal antibodies specific to different MyHC isoforms and by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Our experiments show that the heterochronous intramuscular Isotransplantation procedure had no significant effect on the fiber type composition and MyHC isoform content of the “control” unoperated muscles of the experimental rats when compared to the corresponding muscles of the naive animals. Furthermore, the duration and type of Isotransplantation did not also lead to differences among corresponding “control” muscles of experimental animals. We conclude that the unoperated muscles of the experimental rats can be used as controls in our current transplantation project dealing with long-term grafting experiments.
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regulation of myosin expression in developing and regenerating extrafusal and intrafusal muscle fibers with special emphasis on the role of thyroid hormones
Physiological Research, 2000Co-Authors: Tomas Soukup, I. JirmanováAbstract:Expression of the muscle phenotype is the result of interaction between intrinsic and extrinsic factors, the latter including innervation, mechanical influences and hormonal signals. This minireview summarizes some of the current knowledge regarding the regulation of myosin heavy chain (MHC) isoform transitions during muscle development and regeneration. It describes the role of genetic factors, neural and mechanical influences and it focuses on the contribution of thyroid hormones to the differentiation of muscle fiber phenotypes as shown by the regulation of the expression of MHC isoforms and development of myofibrillar ATPase activity. Finally, it shortly summarizes results regarding the differentiation of MHC isoforms in regenerated muscle fibers of the graft after heterochronous Isotransplantation in rats with different thyroid status.
T. Soukup - One of the best experts on this subject based on the ideXlab platform.
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the effect of a unilateral muscle transplantation on the muscle fiber type and the myhc isoform content in unoperated hind limb slow and fast muscles of the inbred lewis rats
Physiological Research, 2005Co-Authors: Gisela Zacharova, A Vadaszova, Vika Smerdu, G Asmussen, T. SoukupAbstract:To reveal the effect of foreign innervation and altered thyroid status on fiber type composition and the myosin heavy chain (MyHC) isoform expression in the rat slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles, a method of heterochronous Isotransplantation was developed. In this experimental procedure, the SOL or EDL muscles of young inbred Lewis rats are grafted either into the host EDL or SOL muscles of adult rats of the same strain with normal or experimentally altered thyroid status. To estimate the extent of fiber type transitions in the transplanted muscles, the SOL and EDL muscle from the unoperated leg and unoperated muscles from the operated leg could be legitimately used as controls, but only when the experimental procedure itself does not affect these muscles. To verify this assumption, we have compared the fiber type composition and the MyHC isoform content of unoperated contralateral SOL and EDL muscles and ipsilateral unoperated SOL muscle of experimental rats after unilateral Isotransplantation into the host EDL muscle with corresponding muscles of the naive rats of the same age and strain. We provide compelling evidence that the unilateral heterochronous Isotransplantation has no significant effect on the fiber type composition and the MyHC isoform content of unoperated muscles of experimental animals. Hence, these muscles can be used as controls in our grafting experiments.
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Early changes in extrafusal and intrafusal muscle fibers following heterochronous Isotransplantation
Acta neuropathologica, 2001Co-Authors: I. Jirmanová, T. SoukupAbstract:The ultrastructure of regenerating intrafusal and extrafusal fibers was studied 18 h to 30 days after heterochronous Isotransplantation, in which bupivacaine-treated extensor digitorum longus (EDL) or soleus muscles from early postnatal rats were intramuscularly grafted into EDL muscles of adult inbred recipients. As in other models of mammalian muscle regeneration, surviving satellite cells gave rise to presumptive myoblasts, multiplying within the preserved basal lamina tubes at day 4 after grafting. Myoblasts fused to form myotubes with central myonuclei by day 6 after grafting. Extrafusal myotubes differentiated into thin muscle fibers by day 8, which progressively increased in diameter and their nuclei became localized subsarcolemmally from day 13 onwards. The basal laminae of some intrafusal fibers already contained one or more nascent myotubes by day 4 after grafting. Regenerated intrafusal fibers lacked the typical nuclear accumulations and their number varied from one to eight fibers per spindle; additional fibers formed in the periaxial space or between layers of the capsule. Regenerated muscle spindles usually had a thinner outer capsule and a reduced inner capsule and periaxial space. The present study demonstrates that extrafusal and intrafusal muscle fibers degenerate and regenerate after heterochronous Isotransplantation in a manner similar to that in standard grafts. However, the time course is slightly different. Degeneration was completed by day 5 after grafting as in free grafts, but the regeneration of extrafusal and intrafusal fibers started 1 or 2 days earlier, apparently because of the rapid and facilitated revascularization from the host muscle compared to that of standard grafts.
I. Jirmanová - One of the best experts on this subject based on the ideXlab platform.
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Early changes in extrafusal and intrafusal muscle fibers following heterochronous Isotransplantation
Acta neuropathologica, 2001Co-Authors: I. Jirmanová, T. SoukupAbstract:The ultrastructure of regenerating intrafusal and extrafusal fibers was studied 18 h to 30 days after heterochronous Isotransplantation, in which bupivacaine-treated extensor digitorum longus (EDL) or soleus muscles from early postnatal rats were intramuscularly grafted into EDL muscles of adult inbred recipients. As in other models of mammalian muscle regeneration, surviving satellite cells gave rise to presumptive myoblasts, multiplying within the preserved basal lamina tubes at day 4 after grafting. Myoblasts fused to form myotubes with central myonuclei by day 6 after grafting. Extrafusal myotubes differentiated into thin muscle fibers by day 8, which progressively increased in diameter and their nuclei became localized subsarcolemmally from day 13 onwards. The basal laminae of some intrafusal fibers already contained one or more nascent myotubes by day 4 after grafting. Regenerated intrafusal fibers lacked the typical nuclear accumulations and their number varied from one to eight fibers per spindle; additional fibers formed in the periaxial space or between layers of the capsule. Regenerated muscle spindles usually had a thinner outer capsule and a reduced inner capsule and periaxial space. The present study demonstrates that extrafusal and intrafusal muscle fibers degenerate and regenerate after heterochronous Isotransplantation in a manner similar to that in standard grafts. However, the time course is slightly different. Degeneration was completed by day 5 after grafting as in free grafts, but the regeneration of extrafusal and intrafusal fibers started 1 or 2 days earlier, apparently because of the rapid and facilitated revascularization from the host muscle compared to that of standard grafts.
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regulation of myosin expression in developing and regenerating extrafusal and intrafusal muscle fibers with special emphasis on the role of thyroid hormones
Physiological Research, 2000Co-Authors: Tomas Soukup, I. JirmanováAbstract:Expression of the muscle phenotype is the result of interaction between intrinsic and extrinsic factors, the latter including innervation, mechanical influences and hormonal signals. This minireview summarizes some of the current knowledge regarding the regulation of myosin heavy chain (MHC) isoform transitions during muscle development and regeneration. It describes the role of genetic factors, neural and mechanical influences and it focuses on the contribution of thyroid hormones to the differentiation of muscle fiber phenotypes as shown by the regulation of the expression of MHC isoforms and development of myofibrillar ATPase activity. Finally, it shortly summarizes results regarding the differentiation of MHC isoforms in regenerated muscle fibers of the graft after heterochronous Isotransplantation in rats with different thyroid status.
Charmaine J Simeonovic - One of the best experts on this subject based on the ideXlab platform.
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pancreatic islet basement membrane loss and remodeling after mouse islet isolation and transplantation impact for allograft rejection
Cell Transplantation, 2014Co-Authors: Helen F Irvingrodgers, Fui Jium Choong, Katja Hummitzsch, Christopher R Parish, Raymond J Rodgers, Charmaine J SimeonovicAbstract:The isolation of islets by collagenase digestion can cause damage and impact the efficiency of islet engraftment and function. In this study, we assessed the basement membranes (BMs) of mouse pancreatic islets as a molecular biomarker for islet integrity, damage after isolation, and islet repair in vitro as well as in the absence or presence of an immune response after transplantation. Immunofluorescence staining of BM matrix proteins and the endothelial cell marker platelet endothelial cell adhesion molecule-1 (PECAM-1) was performed on pancreatic islets in situ, isolated islets, islets cultured for 4 days, and islet grafts at 3–10 days posttransplantation. Flow cytometry was used to investigate the expression of BM matrix proteins in isolated islet b-cells. The islet BM, consisting of collagen type IV and components of Engelbreth–Holm–Swarm (EHS) tumor laminin 111, laminin a2, nidogen-2, and perlecan in pancreatic islets in situ, was completely lost during islet isolation. It was not reestablished during culture for 4 days. Peri- and intraislet BM restoration was identified after islet Isotransplantation and coincided with the migration pattern of PECAM-1 + vascular endothelial cells (VECs). After islet allotransplantation, the restoration of VEC-derived peri-islet BMs was initiated but did not lead to the formation of the intraislet vasculature. Instead, an abnormally enlarged peri-islet vasculature developed, coinciding with islet allograft rejection. The islet BM is a sensitive biomarker of islet damage resulting from enzymatic isolation and of islet repair after transplantation. After transplantation, remodeling of both peri- and intraislet BMs restores b-cell–matrix attachment, a recognized requirement for b-cell survival, for isografts but not for allografts. Preventing isolation-induced islet BM damage would be expected to preserve the intrinsic barrier function of islet BMs, thereby influencing both the effector mechanisms required for allograft rejection and the antirejection strategies needed for allograft survival.
Vika Smerdu - One of the best experts on this subject based on the ideXlab platform.
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slow to fast muscle transformation following heterochronous Isotransplantation is influenced by host thyroid hormone status
Histochemistry and Cell Biology, 2014Co-Authors: Kateřina Kopecka, Gisela Zacharova, Vika Smerdu, Tomas SoukupAbstract:We studied the effect of regeneration, altered innervation and thyroid hormone (TH) levels on fiber type transitions in slow soleus (SOL) muscles grafted (GRAFT) into host extensor digitorum longus (EDLh) muscles of euthyroid (EU), hyperthyroid (HT) and hypothyroid (HY) Lewis strain rats. SOL muscles were excised from 3-week to 4-week-old inbred Lewis rats and intramuscularly transplanted into EDLh muscles of 2-month-old female rats of the same strain. The proportions of type 1, 2A, 2X and 2B fibers of GRAFT were determined by immunohistochemistry and compared with those of EDLh muscle and EDL and SOL muscles of the unoperated contralateral hind limb. After an average regeneration period of 6-7 months and after being reinnervated by the "fast" peroneal nerve of EDLh muscle, GRAFT was transformed into a fast muscle. However, the extent of GRAFT transformation varied with different TH states. In the EU rats, GRAFT contained about 95 % of fast fibers, among which type 2X and 2B fibers predominated (about 75 %). The transition toward fast muscle phenotype was more pronounced in HT status, where the fastest type 2B fibers predominated. On the contrary, in HY status, the slow to fast transformation was less pronounced, as GRAFT contained less type 2B and 2X but more type 2A and 1 fibers. We conclude that the type of innervation is the crucial factor for the slow to fast fiber type transitions in GRAFT, but the extent of muscle transformation is further modulated by altered TH status.
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fiber type composition of unoperated rat soleus and extensor digitorum longus muscles after unilateral Isotransplantation of a foreign muscle in long term experiments
Physiological Research, 2009Co-Authors: Tomas Soukup, Vika Smerdu, G ZachařovaAbstract:Summary We examined the effects of the unilateral heterochronous Isotransplantation on the fiber type composition and myosin heavy chain (MyHC) isoform content of unoperated slow soleus and fast extensor digitorum longus muscles of female inbred Lewis strain rats. Comparison was made between “control” unoperated muscles of experimental rats (after intramuscular transplantation surgery) with the corresponding muscles of completely naive (unoperated) rats of three age groups (5-, 8and 14-month-old). This was done in order to ascertain whether these muscles can be used as reliable controls to the transplanted and host muscles for our ongoing grafting experiments. The fiber type composition was determined by assessing the histochemical reaction for myofibrillar adenosine triphosphatase, the MyHC isoform content was determined immunocytochemically using monoclonal antibodies specific to different MyHC isoforms and by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Our experiments show that the heterochronous intramuscular Isotransplantation procedure had no significant effect on the fiber type composition and MyHC isoform content of the “control” unoperated muscles of the experimental rats when compared to the corresponding muscles of the naive animals. Furthermore, the duration and type of Isotransplantation did not also lead to differences among corresponding “control” muscles of experimental animals. We conclude that the unoperated muscles of the experimental rats can be used as controls in our current transplantation project dealing with long-term grafting experiments.
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the effect of a unilateral muscle transplantation on the muscle fiber type and the myhc isoform content in unoperated hind limb slow and fast muscles of the inbred lewis rats
Physiological Research, 2005Co-Authors: Gisela Zacharova, A Vadaszova, Vika Smerdu, G Asmussen, T. SoukupAbstract:To reveal the effect of foreign innervation and altered thyroid status on fiber type composition and the myosin heavy chain (MyHC) isoform expression in the rat slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles, a method of heterochronous Isotransplantation was developed. In this experimental procedure, the SOL or EDL muscles of young inbred Lewis rats are grafted either into the host EDL or SOL muscles of adult rats of the same strain with normal or experimentally altered thyroid status. To estimate the extent of fiber type transitions in the transplanted muscles, the SOL and EDL muscle from the unoperated leg and unoperated muscles from the operated leg could be legitimately used as controls, but only when the experimental procedure itself does not affect these muscles. To verify this assumption, we have compared the fiber type composition and the MyHC isoform content of unoperated contralateral SOL and EDL muscles and ipsilateral unoperated SOL muscle of experimental rats after unilateral Isotransplantation into the host EDL muscle with corresponding muscles of the naive rats of the same age and strain. We provide compelling evidence that the unilateral heterochronous Isotransplantation has no significant effect on the fiber type composition and the MyHC isoform content of unoperated muscles of experimental animals. Hence, these muscles can be used as controls in our grafting experiments.