A light and electron microscopic study of ectopic tendon and ligament formation induced by bone morphogenetic protein—13 adenoviral gene therapy

2001 ◽  
Vol 95 (2) ◽  
pp. 298-307 ◽  
Author(s):  
Gregory A. Helm ◽  
Jin Zhong Li ◽  
Tord D. Alden ◽  
Sarah B. Hudson ◽  
Elisa J. Beres ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Skeletal Development ◽  
Light And Electron Microscopy ◽  
Mesenchymal Cell ◽  
Ultrastructural Changes ◽  
Endochondral Bone Formation ◽  
Electron Microscopic ◽  
Content Type ◽  
Time Points ◽  
Fine Print

Object. Bone morphogenetic proteins (BMPs) are involved in the growth and development of many tissues, but it is their role in skeletal development and their unique ability to induce ectopic and orthotopic osteogenesis that have attracted the greatest interest. Expression of the BMP-13 gene is predominantly localized to hypertrophic chondrocytes in regions of endochondral bone formation during development, as well as in mature articular cartilage in the adult. In addition, the application of BMP-13 on a collagen carrier induces neotendon/neoligament formation when delivered subcutaneously or intramuscularly in rodents. The aim of the present study was to determine the histological and ultrastructural changes that occur after the intramuscular injection of a first-generation BMP-13 adenoviral vector. Methods. Athymic nude rats were injected with 3.75 × 1010 plaque-forming units of adenovirus (Ad)-BMP-13 or Ad-β-galactosidase in the thigh musculature, and the region was examined using light and electron microscopy at various time points between 2 days and 100 days postinjection. As early as 2 days after injection of Ad-BMP-13, progenitor cells were observed infiltrating between the transduced muscle fibers. These cells subsequently proliferated, differentiated, and secreted large amounts of collagenous extracellular matrix. By 100 days postinjection, the treated tissue displayed the histological and ultrastructural appearance of neotendon/neoligament, which was clearly demarcated from the surrounding muscle. Small foci of bone and fibrocartilage were also seen within the treated tissue. A short-term bromodeoxyuridine study also demonstrated rapid mesenchymal cell proliferation at the Ad-BMP-13 injection site as early as 48 hours postinjection. At all time points, the control AD-β-gal injection sites were found to contain only normal muscle, without evidence of inflammation or mesenchymal cell proliferation. Conclusions. The results of this study indicate that in the future the use of the BMP-13 gene may have therapeutic utility for the healing of tendon and ligament tears and avulsion injuries.

A light and electron microscopic study of ectopic tendon and ligament formation induced by bone morphogenetic protein–13 adenoviral gene therapy

2000 ◽  
Vol 8 (4) ◽  
pp. 1-8 ◽  
Author(s):  
Gregory A. Helm ◽  
Jin Zhong Li ◽  
Tord D. Alden ◽  
Sarah A. Hudson ◽  
Elisa J. Beres ◽  
...  
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Skeletal Development ◽  
Light And Electron Microscopy ◽  
Mesenchymal Cell ◽  
Ultrastructural Changes ◽  
Endochondral Bone Formation ◽  
Electron Microscopic ◽  
Endochondral Bone ◽  
Morphogenetic Protein ◽  
Ultrastructural Appearance

Object Bone morphogenetic proteins (BMPs) are involved in the growth and development of many tissues, but it is their role in skeletal development and their unique ability to induce ectopic and orthotopic osteogenesis that has attracted the greatest interest. Expression of the BMP-13 gene has been shown to be predominantly localized to hypertrophic chondrocytes in regions of endochondral bone formation during development, as well as in mature articular cartilage in the adult. In addition, the application of BMP-13 on a collagen carrier induces neotendon/ligament formation when delivered subcutaneously or intramuscularly in rodents. The aim of the present study was to determine the histological and ultrastructural changes that occur after the intramuscular injection of a first-generation BMP-13 adenoviral vector. Methods Athymic nude rats were injected with 3.75 × 1010 plaque-forming unit adenovirus (Ad)-BMP-13 or Ad-β-galactosidase in the thigh musculature, and the regions examined using light and electron microscopy at various time points between 2 and 100 days postinjection. As early as 2 days after injection of Ad-BMP-13, progenitor cells were observed infiltrating between the transduced muscle fibers. These cells subsequently proliferated, differentiated, and secreted large amounts of collagenous extracellular matrix. By 100 days postinjection, the induced tissue had the histological and ultrastructural appearance of neotendon/ligament, which was clearly demarcated from the surrounding muscle. Small foci of bone and fibrocartilage were also seen within the induced tissue. A short-term bromodeoxyuri-dine study also demonstrated rapid mesenchymal cell proliferation at the Ad-BMP-13 injection site as early as 48 hours postinjection. Conclusions The results of this study suggest that in the future the use of the BMP-13 gene may have therapeutic utility for the healing of tendon and ligament tears and avulsion injuries.

Extravascular collagen in the human epileptic brain: a potential substrate for aberrant cell migration in cases of temporal lobe epilepsy

2002 ◽  
Vol 97 (5) ◽  
pp. 1125-1130 ◽  
Author(s):  
Erol Veznedaroglu ◽  
Elisabeth J. Van Bockstaele ◽  
Michael J. O'Connor
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Granule Cells ◽  
Light And Electron Microscopy ◽  
Cellular Migration ◽  
Temporal Lobectomy ◽  
Electron Microscopic ◽  
Content Type ◽  
Microscopic Evaluation ◽  
Fine Print

Object. Several lines of evidence have demonstrated a number of cellular changes that occur within the hippocampus in patients with temporal lobe epilepsy (TLE). These include aberrant migration of granule cells and sprouting of mossy fibers, processes that have been linked to the hyperexcitability phenomenon observed in cases of TLE. In the present study the authors examined brain tissues obtained in patients undergoing temporal lobectomy surgery and in patients at autopsy (normal human control specimens), and compared the subcellular composition of regions of the hippocampus containing dispersed granule cells. Methods. Six human hippocampi were obtained in patients undergoing temporal lobectomies for intractable seizures. The patients ranged in age from 24 to 50 years. Two of the six patients had a history of head trauma and one had experienced a febrile seizure during childhood. Immediately following excision from the brain, the tissue was placed in an acrolein—paraformaldehyde fixative. The hippocampi were processed along with six human brain control specimens obtained at autopsy for light and electron microscopic evaluation. The tissues were then labeled for collagen types I through IV. Positive collagen labeling was identified, with the aid of both light and electron microscopy, in the parenchyma of all patients with TLE but not in the control tissues. Conclusions. The authors report the first localization of collagen outside of the vasculature and meninges in the brains of patients with TLE. Recent evidence of collagen's chemoattractant properties and its role in epileptogenesis in animal models suggests that collagen may play a role in cellular migration and seizure activity in a subset of patients. Further studies with a larger series of patients are warranted.

Ultrastructural changes in arteriovenous malformations after gamma knife surgery: an electron microscopic study

2005 ◽  
Vol 102 ◽  
pp. 289-292 ◽  
Author(s):  
György T. Szeifert ◽  
Ottó Major ◽  
Andras A. Kemeny
Keyword(s):  
Electron Microscopy ◽  
Gamma Knife ◽  
Cell Population ◽  
Arteriovenous Malformations ◽  
Spindle Cell ◽  
Gamma Knife Surgery ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Content Type ◽  
Fine Print

Object.The authors analyzed morphological alterations at the subcellular level by undertaking transmission electron microscopy in arteriovenous malformations (AVMs) after gamma knife surgery (GKS).Methods.Histological, immunohistochemical, and electron microscopic investigations were performed in a series of pathological specimens obtained in seven patients. The patients harbored cerebral AVMs that had been previously treated with GKS and had suffered subsequent bleeding 10 to 52 months after treatment.Histological studies revealed spindle cell proliferation in the connective tissue stroma and in the subendothelial region of the irradiated AVM vessels. Electron microscopy demonstrated different ultrastructural characteristics of this spindle cell population. There were cells with a smooth-edged oval nuclei surrounded by massive bundles of collagen fibers in the extracellular matrix. Other cells with the same nuclear morphology contained abundant intracytoplasmic filaments. Nuclear deformation was connected to a fibrillary system developed within the cytoplasm, and peripheral attachment sites were related to an extracellular layer of basement membrane—like material arranged parallel to the cell border. Also present were cells containing well-developed cisterns of rough endoplasmic reticulum and dense bodies at the periphery of the cytoplasm with folded, irregular nuclei.Conclusions.The ultrastructural and histological characteristics of the spindle cell population in the GKS-treated AVMs are similar to those designated as myofibroblasts in wound healing processes and pathological fibromatoses. Because similar cell modifications have not been demonstrated in control nonirradiated AVM specimens, these myofibroblasts may contribute to the shrinking process and final occlusion of AVMs after radiosurgery.

Ultrastructural changes in arteriovenous malformations after gamma knife surgery: an electron microscopic study

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 289-292 ◽  
Author(s):  
György T. Szeifert ◽  
Ottó Major ◽  
Andras A. Kemeny
Keyword(s):  
Electron Microscopy ◽  
Gamma Knife ◽  
Cell Population ◽  
Arteriovenous Malformations ◽  
Spindle Cell ◽  
Gamma Knife Surgery ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Content Type ◽  
Fine Print

Object. The authors analyzed morphological alterations at the subcellular level by undertaking transmission electron microscopy in arteriovenous malformations (AVMs) after gamma knife surgery (GKS). Methods. Histological, immunohistochemical, and electron microscopic investigations were performed in a series of pathological specimens obtained in seven patients. The patients harbored cerebral AVMs that had been previously treated with GKS and had suffered subsequent bleeding 10 to 52 months after treatment. Histological studies revealed spindle cell proliferation in the connective tissue stroma and in the subendothelial region of the irradiated AVM vessels. Electron microscopy demonstrated different ultrastructural characteristics of this spindle cell population. There were cells with a smooth-edged oval nuclei surrounded by massive bundles of collagen fibers in the extracellular matrix. Other cells with the same nuclear morphology contained abundant intracytoplasmic filaments. Nuclear deformation was connected to a fibrillary system developed within the cytoplasm, and peripheral attachment sites were related to an extracellular layer of basement membrane—like material arranged parallel to the cell border. Also present were cells containing well-developed cisterns of rough endoplasmic reticulum and dense bodies at the periphery of the cytoplasm with folded, irregular nuclei. Conclusions. The ultrastructural and histological characteristics of the spindle cell population in the GKS-treated AVMs are similar to those designated as myofibroblasts in wound healing processes and pathological fibromatoses. Because similar cell modifications have not been demonstrated in control nonirradiated AVM specimens, these myofibroblasts may contribute to the shrinking process and final occlusion of AVMs after radiosurgery.

The deposition of Hg203-chlormerodrin in experimental brain tumors

1971 ◽  
Vol 35 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Tatsuya Kobayashi ◽  
Louis Bakay ◽  
Joseph C. Lee
Keyword(s):  
Brain Tumors ◽  
Tumor Cells ◽  
Normal Brain ◽  
Intracranial Tumors ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Content Type ◽  
Meningeal Tumors ◽  
Vacuolar System ◽  
Fine Print

✓ The deposition of Hg203-chlormerodrin was studied in intracranial tumors in mice induced by implantation of 20-methyl cholanthrene by tissue assay, as well as light microscopic and electron microscopic autoradiography. The investigations were carried out in astrocytomas, glioblastomas, and meningeal tumors. The chlormerodrin content of the tumors exceeded that of normal brain with a significant tumor/brain ratio ranging from 5.8 to 22.5. It was found that the chlormerodrin molecule becomes rapidly incorporated in the tumor cells, with a preference for that portion of the cytoplasm associated with the vacuolar system.

Decompressive craniectomy in a rat model of “malignant” cerebral hemispheric stroke: experimental support for an aggressive therapeutic approach

1996 ◽  
Vol 85 (5) ◽  
pp. 853-859 ◽  
Author(s):  
Arnd Doerfler ◽  
Michael Forsting ◽  
Wolfgang Reith ◽  
Christian Staff ◽  
Sabine Heiland ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Decompressive Craniectomy ◽  
Control Group ◽  
Acute Ischemia ◽  
Vessel Occlusion ◽  
Content Type ◽  
Time Points ◽  
Infarction Size ◽  
Mca Occlusion ◽  
Fine Print

✓ Acute ischemia in the complete territory of the carotid artery may lead to massive cerebral edema with raised intracranial pressure and progression to coma and death due to uncal, cingulate, or tonsillar herniation. Although clinical data suggest that patients benefit from undergoing decompressive surgery for acute ischemia, little data about the effect of this procedure on experimental ischemia are available. In this article the authors present results of an experimental study on the effects of decompressive craniectomy performed at various time points after endovascular middle cerebral artery (MCA) occlusion in rats. Focal cerebral ischemia was induced in 68 rats using an endovascular occlusion technique focused on the MCA. Decompressive cranioectomy was performed in 48 animals (in groups of 12 rats each) 4, 12, 24, or 36 hours after vessel occlusion. Twenty animals (control group) were not treated by decompressive craniectomy. The authors used the infarct volume and neurological performance at Day 7 as study endpoints. Although the mortality rate in the untreated group was 35%, none of the animals treated by decompressive craniectomy died (mortality 0%). Neurological behavior was significantly better in all animals treated by decompressive craniectomy, regardless of whether they were treated early or late. Neurological behavior and infarction size were significantly better in animals treated very early by decompressive craniectomy (4 hours) after endovascular MCA occlusion (p < 0.01); surgery performed at later time points did not significantly reduce infarction size. The results suggest that use of decompressive craniectomy in treating cerebral ischemia reduces mortality and significantly improves outcome. If performed early after vessel occlusion, it also significantly reduces infarction size. By performing decompressive craniectomy neurosurgeons will play a major role in the management of stroke patients.

Progression of partial experimental injury to peripheral nerve

1975 ◽  
Vol 42 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Alan R. Hudson ◽  
David G. Kline
Keyword(s):  
Recovery Of Function ◽  
Electron Microscopic Examination ◽  
Ground Substance ◽  
Electron Microscopic ◽  
Early Recovery ◽  
Content Type ◽  
Proximal Stimulus ◽  
Late Recovery ◽  
Fine Print ◽  
Experimental Injury

✓ Biopsies from partially lacerated nerves were taken at the sites of proximal stimulus, laceration, and distal recording, and from stimuli and recording sites of control nerves. Electron microscopic examination of the partially lacerated major fasciculus revealed three zones of injury. The laceration zone showed neurotemetic changes, the adjacent or intermediate zone, partial degeneration, and the zone most peripheral to the laceration, changes in ground substance. Progression of the original injury is apparently due to ongoing changes in the intermediate and peripheral zones while much of the relative early recovery is due to reversal of changes in these zones. Regeneration through the laceration or neurotemetic zone is limited but does account for a small amount of late recovery of function.

Ultrastructure of the human posttraumatic syrinx

1989 ◽  
Vol 71 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Kesava K. V. Reddy ◽  
Marc R. Del Bigio ◽  
Garnette R. Sutherland
Keyword(s):  
Central Canal ◽  
Ependymal Cells ◽  
Electron Microscopic ◽  
Content Type ◽  
Microscopic Features ◽  
Cell Processes ◽  
Ultrastructural Appearance ◽  
Posttraumatic Syringomyelia ◽  
Communicating Syringomyelia ◽  
Fine Print

✓ Although posttraumatic syringomyelia is a well-established clinicopathological entity, there is a paucity of information on the ultrastructural features of this condition. This study documents the light and electron microscopic features of posttraumatic syringes obtained from two patients who underwent surgical cordectomy. The syringes were lined largely by cell processes of astrocytes. Small regions near the caudal end were lined by flattened ependymal cells that lacked surface specializations. These were thought to represent remnants of the central canal ependyma. The ultrastructural appearance of the syrinx was similar to that of the communicating syringomyelia as well as the periventricular changes that accompany hydrocephalus. The authors conclude that the changes represent the nonspecific sequelae of a distensile force within the syrinx cavity.

Chordoma of the skull base: predictors of tumor recurrence

2003 ◽  
Vol 98 (4) ◽  
pp. 812-822 ◽  
Author(s):  
Roberto Pallini ◽  
Giulio Maira ◽  
Francesco Pierconti ◽  
Maria Laura Falchetti ◽  
Ester Alvino ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Microsatellite Instability ◽  
Skull Base ◽  
Tumor Recurrence ◽  
Doubling Time ◽  
P53 Protein ◽  
Biological Behavior ◽  
Htert Mrna ◽  
Content Type ◽  
Fine Print

Object. Chordomas of the skull base are generally regarded as slow-growing tumors; however, approximately 20% of these lesions have been shown to recur as early as 1 year postsurgery. The classic pathological paradigms are poor predictors of outcome, and additional markers are needed to identify patients at risk for early tumor recurrence. In this study the authors describe such a marker. Methods. In a series of 26 patients with chordomas of the skull base, the authors investigated the relationship between the biological behavior of the tumor, which was determined according to the interval for its recurrence and volume doubling time, and several pathological and molecular features, which included the histological variant, proliferative activity, mutation of p53 protein, expression of human telomerase reverse transcriptase (hTERT) messenger (m)RNA, loss of heterozygosity (LOH), and microsatellite instability. The major finding in this study was that hTERT mRNA expression in chordoma cells identifies those tumors that exhibit unusually fast rates of growth. The expression of hTERT mRNA was frequently associated with mutation of p53 protein, indicating that telomerase dysfunction combines with abnormal p53 function to initiate the unrestrained clonal expansion of the tumor cells. In cases in which the tumor was partially removed, mutation of p53 protein and expression of hTERT mRNA predicted increased doubling time for residual tumor as well as the probability of tumor recurrence. Cell proliferation, as investigated using the Ki-67 method, was significantly related to the tumor doubling time; however, the authors found that the pattern of cell proliferation was not homogeneous throughout the chordoma tissue, and that the proliferative index might change by a factor as high as 8 among different regions of the same tumor. The LOH and microsatellite instability do not seem to affect the prognosis of skull base chordomas. Conclusions. Reactivation of telomerase in chordomas is a reliable predictor of outcome. The ability to predict the biological behavior of chordomas might have immediate implications in the management of this disease in patients who undergo surgery.

Site-specific immune response to implanted gliomas

2001 ◽  
Vol 95 (6) ◽  
pp. 1012-1019 ◽  
Author(s):  
Martin A. Proescholdt ◽  
Marsha J. Merrill ◽  
Barbara Ikejiri ◽  
Stuart Walbridge ◽  
Aytac Akbasak ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Tumor Growth ◽  
Mhc Class Ii ◽  
Lymphocytic Infiltration ◽  
Class Ii ◽  
Content Type ◽  
Time Points ◽  
Early Tumor ◽  
The Brain ◽  
Fine Print

Object. Immunotherapy for glioblastoma has been uniformly ineffective. The immunological environment of the brain, with its low expression of major histocompatibility complex (MHC) molecules and limited access for inflammatory cells and humoral immune effectors due to the blood—brain barrier (BBB), may contribute to the failure of immunotherapy. The authors hypothesize that brain tumors are protected from immune surveillance by an intact BBB at early stages of development. To investigate the immunological characteristics of early tumor growth, the authors compared the host response to a glioma implanted into the brain and into subcutaneous tissue. Methods. Samples of tumors growing in the brain or subcutaneously in rats were obtained for 7 consecutive days and were examined immunohistochemically for MHC Class I & II molecules, and for CD4 and CD8 lymphocyte markers. Additionally, B7-1 costimulatory molecule expression and lymphocyte-specific apoptosis were examined. Conclusions. On Days 3 and 4 after implantation, brain tumors displayed significantly lower MHC Class II expression and lymphocytic infiltration (p < 0.05). After Day 5, however, no differences were detected. The MHC Class II expressing cells within the brain tumors appeared to be infiltrating microglia. Minimal B7-1 expression combined with lymphocyte-specific apoptosis were detected in both brain and subcutaneous tumors. Low MHC Class II expression and low lymphocytic infiltration at early time points indicate the importance of the immunologically privileged status of the brain during early tumor growth. These characteristics disappeared at later time points, possibly because the increasing perturbation of the BBB alters the specific immunological environment of the brain. The lack of B7-1 expression combined with lymphocyte apoptosis indicates clonal anergy of glioma-infiltrating lymphocytes regardless of implantation site.

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