Primitive Mesenchymal Cells Research Articles

Pseudogranular Cell Tumor Of The Skin

A skin biopsy from a nasal lesion showed a dermal infiltrating neoplasm composed of polygonal cells with small nuclei and abundant coarsely granular eosinophilic cytoplasm. Light microscopic features were that of a granular cell tumor. However, the results of the immunohistologic studies and the observations of the electron microscopic studies did not identify the nature of the cells nor did they confirm that it was a granular cell tumor. We interpret the lesion as a pseudogranular cell tumor of the skin. SOURCE OF SUPPORT None REPORT OF A CASE A 66-year-old white female presented with a painless skin papule located on the right side of her nose that had been present for unknown period of time. There were no other symptoms and her past medical history was unremarkable. The biopsied skin lesion showed an intact normal epidermis. The dermis showed a proliferation of polygonal cells with abundant coarsely granular eosinophilic cytoplasm and small round or ovoid nuclei (Figs. 1 and 2) leading to an impression of a granular cell tumor. Figure 1 Figure 1: Dermal proliferation of polygonal cells with eosinophilic granular cytoplasm (low power). Figure 2 Figure 2: High power view of the tumor. Immunohistochemical stains showed that the tumor cells were positive for CD34, CD68, and vimentin and negative for S100 protein, Melan A, HMB45, Factor VIIIa, pancytokeratin, desmin, and SMA. Ultrastucturally (Fig. 3), the dermal polygonal cells showed numerous intracytoplasmic phagosome-like vesicles, many containing electron-dense irregular material. The mitochondria and endoplasmic reticulum were scarce. The cells did not show any features of melanocyte, Schwann cell or classic mitochondria-rich granular cells. Pseudogranular Cell Tumor Of The Skin 2 of 3 Figure 3 Figure 3: Electron microscopic picture showing numerous cytoplasmic phagosome-like vesicles. Mitochondria are scarce. No melanosomes or dense core granules are seen. 5000X. COMMENT Granular cell tumors are neural-derived tumors commonly arising in the upper aerodigestive tract and skin. A typical granular cell tumor of the skin is composed of polyhedral cells with large amount of granular eosinophilic cytoplasm involving the dermis. The cells are typically immunoreactive for S-100 protein signifying a neural origin and are negative for epithelial, muscle, and endothelial markers [1]. In our case, the polygonal dermal cells with eosinophilic granular cytoplasm, on immunostains, are not suggestive of a neural, melanocytic, epithelial, or smooth muscle origin. Electron microscopic observation of a lack of abundant lysosomes is unlike that of a granular cell tumor. Other primitive mesenchymal cell tumors may present as a granular cell proliferations. The CD34 and CD68 reactivity in our case may suggest that the polygonal cells are fibroblastic in origin. CD-34 positive and S-100 negative granular cell dendrocytosis has been described as a congenital lesion [2]). Another possibility considered was a possible oncocytic change in a dermal melanocytic nevus [3]. However, the cells in such cases are S-100 positive and ultrastucturally they show numerous mitochondria near the melanosomes. Other non-neural tumors showing nonspecific granular change include dermatofibroma, fibroxanthoma, leiomyoma, leiomyosarcoma, angiosarcoma, and basal cell carcinoma [4]. Our case did not show any microscopic, immunohistochemical, or ultrastuctural features of any of these tumors. The true origin of our tumor has not been established with certainty. Some of the nuclear changes observed in the ultrastrucural study may be indicative of apoptosis and the granular changes in the cytoplasm may represent degenerative changes. Pseudogranular cell tumor may be a reasonable descriptive name for such a lesion. CORRESPONDENCE TO Deba P Sarma, MD Department of Pathology Creighton University Medical Center Omaha, NE 68131 Tel: 402-449-4951 debasarma@creighton.edu

Bortezomib Induces Proliferation of Mesenchymal Progenitor Cells and Promotes Differentiation towards Osteoblastic Lineage.

Bortezomib is a first-in-class proteasome inhibitor approved for the therapy of relapsed, refractory multiple myeloma (MM). Two large registration trials (SUMMIT and APEX) of bortezomib in MM revealed an increase in the serum levels of bone-specific alkaline phosphatase (b-ALP) and osteocalcin (ocn) in bortezomib-responsive patients, raising the prospect that bortezomib may influence the bone marrow (BM) microenvironment in association with its anti-myeloma effect,. However, the precise cellular target of bortezomib within the BM milieu remains unknown. We hypothesized that the observed rise in b-ALP and ocn was the result of direct effects of bortezomib on osteoblast-lineage committed cells. The effect of bortezomib on osteoblastic cells was first evaluated in in vitro. When bortezomib was added to freshly isolated primary BM mononuclear cells, the CFU-Ob (osteoblastic colony-forming units) was unchanged, but the colony size was increased, with a maximum effect observed at 1 nM. In particular, bortezomib increased the number of CD45−/CD51+ cells 1.8 fold (P<0.05), while no change was noted in the CD45+ (hematopoietic) cells. These CD45−/CD51+ cells expressed Collagen-1 and b-ALP, rapidly formed VanKossa+ bone nodules in vitro and lacked the expression of Sca1 and Collagen-II, suggesting that they were of osteoblastic lineage. When mice were treated with bortezomib (0.1mg/kg biw for 3 weeks), a significant increase in CD45−/CD51+ cells was observed in the bone marrow suggesting bortezomib increases the number of osteoblast-lineage cells in vivo. Next, we sought to identify the target cell for bortezomib activity. We treated CD45− BMSCs with bortezomib in vitro for 7 days and then exposed these cells to either adipogenic or osteogenic media (with bortezomib now removed). Interestingly, both differentiated osteoblasts (i.e Van-Kossa+ cells) and adipocytes (Oil-Red staining cells) were increased, suggesting that bortezomib increases the proliferation of a bipotent MPC. We then studied the impact of bortezomib on the commitment of MPCs towards osteoblastic or adipocytic lineages by culturing CD45− cells in osteogenic and adipogenic media with concurrent treatment with bortezomib. In these conditions, we found an increased number of Alk-Phos + osteoblasts in bortezomib-treated cells and a decreased number of adipocytes in adipogenic media. These data suggest that bortezomib (a) increases the proliferation of uncommitted MPCs and (b) promotes the differentiation towards osteoblastic lineage. To investigate the mechanism of bortezomib action, we studied the effect of forskolin, a cyclic AMP analogue known to accelerate the ubiquitin-mediated degradation of RUNX-2, the master-regulator of osteogenic differentiation. Forskolin treatment abrogated the effect of bortezomib on CD45− BMSCs, suggesting that bortezomib activity is influenced by the adenylate cyclase pathway, possibly through bortezomib-mediated inhibition of RUNX-2 degradation. Bortezomib alters primitive mesenchymal cell function causing increased osteoblast lineage cells.

Calpain System Regulates the Differentiation of Adult Primitive Mesenchymal ST-13 Adipocytes

The activity of calpain, a calcium-activated protease, is required during the mitotic clonal expansion phase of 3T3-L1 embryonic preadipocyte differentiation. Here we examined the role of calpain in the adipogenesis of ST-13 preadipocytes established from adult primitive mesenchymal cells, which do not require mitotic clonal expansion. After exposure to the calpain inhibitor, N-benzyloxycarbonyl-L-leucyl-L-leucinal or overexpression of calpastatin, a specific endogenous inhibitor of calpain, ST-13 preadipocytes acquired the adipocyte phenotype. Overexpression of calpastatin in ST-13 adipocytes stimulated the expression of adipocyte-specific CCAAT/enhancer-binding protein-alpha (C/EBPalpha), peroxisome proliferator-activated receptor (PPAR)-gamma, sterol regulatory element-binding protein 1, and the insulin signaling molecules, insulin receptor alpha, insulin-receptor substrates, and GLUT4. However, insulin-stimulated glucose uptake was reduced by approximately 52%. The addition of calpain to the nuclear fraction of ST-13 adipocytes resulted in the Ca(2+)-dependent degradation of PPARgamma and C/EBPalpha but not sterol regulatory element-binding protein 1. Exposing ST-13 adipocytes to A23187 also led to losses of endogenous PPARgamma and C/EBPalpha. Under both conditions, calpain inhibitors almost completely prevented C/EBPalpha cleavage but partially blocked the decrease of PPARgamma. Two ubiquitous forms of calpain, mu- and m-calpain, localized to the cytosol and the nucleus, whereas the activated form of mu- but not m-calpain was found in the nucleus. Finally, stable dominant-negative mu-calpain transfectants showed accelerated adipogenesis and increase in the levels of PPARgamma and C/EBPalpha during adipocyte program. These results support evidence that the calpain system is involved in regulating the differentiation of adult primitive mesenchymal ST-13 preadipocytes.

Nrf2 Negatively Regulates Osteoblast Differentiation via Interfering with Runx2-dependent Transcriptional Activation

Nrf2 (nuclear factor E2 p45-related factor 2) is believed to be a transcription factor essential for the regulation of many detoxifying and antioxidative genes in different tissues. In the present study, we investigated the role of Nrf2 in the regulation of osteoblastic differentiation. nrf2 mRNA expression was significantly up-regulated in femur isolated from ovariectomized mice, whereas in situ hybridization analysis revealed that up-regulation of nrf2 mRNA was mainly found in osteoblasts attached on cancellous bone in femur of ovariectomized mice. Expression of Nrf2 protein was also seen in osteoblasts in neonatal mouse tibia and calvaria. In osteoblastic MC3T3-E1 cells stably transfected with nrf2 expression vector, significant inhibition was seen in the maturation-dependent increase in alkaline phosphatase activity as well as the mineralized matrix formation. Stable overexpression of nrf2 significantly impaired Runx2 (runt-related transcription factor 2)-dependent stimulation of osteocalcin promoter activity and recruitment of Runx2 on osteocalcin promoter without affecting the expression of runx2 mRNA. Coimmunoprecipitation and mammalian two-hybrid assay revealed a physical interaction between Runx2 and Nrf2, whereas cellular distribution of endogenous Runx2 was not apparently changed by nrf2 overexpression in MC3T3-E1 cells. Alternatively, Nrf2 bound to antioxidant-responsive element-like-2 sequence of osteocalcin promoter. The inhibition by nrf2 on runx2-dependent osteocalcin promoter activity was partially prevented by the introduction of reporter of deletion mutant for ARE-like-2 sequence of osteocalcin promoter. These data suggest that Nrf2 may negatively regulate cellular differentiation through inhibition of the Runx2-dependent transcriptional activity in osteoblasts.

Phosphaturic mesenchymal tumor (mixed connective tissue variant): a case report with spectral analysis

We present a further case of a rare mesenchymal neoplasm termed phosphaturic mesenchymal tumor (mixed connective tissue variant). The patient was a 42-year-old man with a long history of osteomalacia of unknown etiology with pathological bone fracture, abnormality of parathyroid glands, kyphosis, scoliosis, and spondylosis. Laboratory investigation disclosed hypophosphatemia, elevated serum alkaline phosphatase activity, and normal serum calcium level. The patient had a soft tissue mass in the right inguinal area, measuring 11 x 6 x 5 cm, which was previously interpreted as a calcified hematoma on sonography. The tumor was surgically removed. Grossly, the tumor was well circumscribed, unencapsulated, and had soft to dense consistency. The cut surface had a variegated appearance due to the presence of large hemorrhagic areas admixed with foci of grey-yellow tissue. Histologically, the tumor was composed of primitive mesenchymal cells, osteoclast-like cells, and cells showing myofibroblastic features without cytologic atypia. There were a well developed vascular network, microcystic areas, and poorly formed cartilaginous foci. Unusual and hitherto unpublished prominent features were flower-like, slate-gray crystals, widespread hemosiderin deposits and large areas of hemorrhages, with the latter comprising approximately 60% of the tumor. A spectral analysis indicated that chemically, the crystals mainly consisted of calcium phosphate and sodium nitrate.

256. Novel Therapeutic Strategy for Ischemic Stroke by Bone Marrow Stromal Cells and Ex Vivo HGF and FGF2 Genes Transfer with Replication-Incompetent HSV-1 Vector

The bone marrow stromal cells (MSCs), including the primitive pluriopotent mesenchymal stem cells (PMSCs) and the multipotent adult progenitor cells (MAPCs), are attractive targets for cell and gene therapy for various central nervous system disorders.Material and method: For gene modification of MSCs, we used a replication-incompetent HSV-1 vector “1764/4-”, triple-deletion mutant of the ICP4, ICP34.5, and VP16. This vector has very high ability of gene transduction to MSC, 70-75% at MOI 10 and 95% at MOI 50, and its expression can carry on at least one month at high level. Two kinds of vectors expressing HGF and FGF-2 were prepared for this study. FGF-2 vector contains the signal sequence of Interleukin-2 (IL-2ss) ahead of FGF-2 gene to enhance its extracellular secretion, because native FGF2 gene don't have the excretion signal. Native MSCs, HGF-MSCs, IL2ss+FGF-2-MSCs and PBS were administered directly into the lesioned brain 24 hours after transient middle cerebral artery occlusion (MCAO) of adult Wister rats.Results: At day 14, each gene modified MSC group showed significant improvement in modified neurological severity score (mNSS) and apparent decreasing of infarct volume compared with native MSC or sham-operated group. (p<0.05). HGF and FGF-2 expression in vivo were strongly kept through the experimental period. In HGF modified MSC-treated group, the MAP-2 positive cell% tends to increase and the TUNEL positive cell% decrease in the ischemic boundary zone (IBZ). The transdifferentiation of transplanted MSCs to central nervous system cell phenotypes was also checked. Most of the transdifferentiated phenotype was GFAP- positive, and the Nestin-positive cells were scarcely able to find out in the host brain.Discussion and Conclusion: By using the replication- incompetent HSV-1 vector, MSCs can be efficiently engineered to secrete a series of various cytokines in large quantities and in the long term in vitro and in vivo that could potentially treat the ischemic stroke of the brain. HGF and FGF-2 gene-transferred MSCs, achieved the remarkable amelioration of neurological symptoms and apparent decreasing of infarct volume comparison with native MSCs in rat MCAO model. It would be appeared that the main mechanism of these therapeutic effects is the neuroprotection (anti-apoptotic effect) in IBZ by various abundant cytokines secreted from gene engineered MSCs. We will present our detail data of the study and the perspective of this therapeutic strategy. The bone marrow stromal cells (MSCs), including the primitive pluriopotent mesenchymal stem cells (PMSCs) and the multipotent adult progenitor cells (MAPCs), are attractive targets for cell and gene therapy for various central nervous system disorders. Material and method: For gene modification of MSCs, we used a replication-incompetent HSV-1 vector “1764/4-”, triple-deletion mutant of the ICP4, ICP34.5, and VP16. This vector has very high ability of gene transduction to MSC, 70-75% at MOI 10 and 95% at MOI 50, and its expression can carry on at least one month at high level. Two kinds of vectors expressing HGF and FGF-2 were prepared for this study. FGF-2 vector contains the signal sequence of Interleukin-2 (IL-2ss) ahead of FGF-2 gene to enhance its extracellular secretion, because native FGF2 gene don't have the excretion signal. Native MSCs, HGF-MSCs, IL2ss+FGF-2-MSCs and PBS were administered directly into the lesioned brain 24 hours after transient middle cerebral artery occlusion (MCAO) of adult Wister rats. Results: At day 14, each gene modified MSC group showed significant improvement in modified neurological severity score (mNSS) and apparent decreasing of infarct volume compared with native MSC or sham-operated group. (p<0.05). HGF and FGF-2 expression in vivo were strongly kept through the experimental period. In HGF modified MSC-treated group, the MAP-2 positive cell% tends to increase and the TUNEL positive cell% decrease in the ischemic boundary zone (IBZ). The transdifferentiation of transplanted MSCs to central nervous system cell phenotypes was also checked. Most of the transdifferentiated phenotype was GFAP- positive, and the Nestin-positive cells were scarcely able to find out in the host brain. Discussion and Conclusion: By using the replication- incompetent HSV-1 vector, MSCs can be efficiently engineered to secrete a series of various cytokines in large quantities and in the long term in vitro and in vivo that could potentially treat the ischemic stroke of the brain. HGF and FGF-2 gene-transferred MSCs, achieved the remarkable amelioration of neurological symptoms and apparent decreasing of infarct volume comparison with native MSCs in rat MCAO model. It would be appeared that the main mechanism of these therapeutic effects is the neuroprotection (anti-apoptotic effect) in IBZ by various abundant cytokines secreted from gene engineered MSCs. We will present our detail data of the study and the perspective of this therapeutic strategy.

Solitary Fibrous Tumors of the Pleura: Report of Eight Cases and Literature Review

Primary pleural tumors have been classified as diffuse or localized types. The diffuse type or malignant mesothelioma (MM) is the most frequently encountered lesion. Localized variety is less frequent and defined. Although its hystogenesis is not well established, new histological and immunohistochemical techniques are giving us a better understanding of it. Now, the common consensus is that this tumor origins from a primitive submesothelial mesenchymal cell (16,17,18,19). Concerning the advances done during the last decade in the understanding, imaging, diagnostic and therapeutic approaches to this rare tumor, we decided to conduct a retrospective study of the cases seen at our institution and a review of the available English literature.

Regeneration of parietal and visceral peritoneum in the immature animal: a light and electron microscopical study.

Abstract The healing of visceral and parietal peritoneum has been investigated in the immature animal by both light and electron microscopy. Healing has been found to occur more rapidly in the immature animal when compared with the adult animal. Parietal peritoneum was covered by a new mesothelium in 7 days, while the liver was covered in 5 days. The new mesothelium developed from subperitoneal perivascular connective-tissue cells but it was not possible to determine whether these were primitive mesenchymal cells or fibroblasts. The findings are discussed in relation to the pathogenesis of peritoneal adhesions.

Lineage-Specific Expression and Functional Relevance of MicroRNA Genes in Normal Hematopoiesis.

MicroRNAs (miRs) are a class of a small (~ 22nt) RNAs, which play an important role in the negative regulation of gene expression by base-pairing to complementary sites on the target mRNAs. While it is established that miRs are involved in a variety of basic processes, e.g., cell proliferation and apoptosis, neural development, fat metabolism and stress response, little is known on their expression and function in hematopoiesis. In order to investigate miR expression in erythropoietic (E), megakaryocytic (Mk), granulopoietic (G) and monocytopoietic (Mo) lineages, we have assayed their level at discrete sequential stages of the E, Mk, G or Mo series in unilineage differentiation/maturation cultures of cord blood (CB) CD34+ cells. The analysis was performed using a microarray chip containing as probes gene-specific 40mer oligonucleotides, generated from 161 human and 84 mouse precursors miRs (Liu GC et al., PNAS, 2004). Northern blot analysis confirmed the microarray data. The results indicate that the majority of the analyzed miRs is not expressed in CB hematopoietic cells. However, 49 miRs are expressed at significant levels in CD34+ cells: in most cases the expression level declines during hematopoietic differentiation according to diverse patterns, i.e., the decline may be more or less pronounced, more or less rapid and differ in the diverse hematopoietic lineages. As expression pattern examples, we observed that: (a) miR 223 is strongly downmodulated in the E lineage, whereas its level is not affected or increased in the other series; (b) miR 221 and 222 level sharply declines in the E lineage, while the drop is less pronounced in the Mk, G and Mo series; conversely, (c) miR 17, 20, 106 are downmodulated prevalentely in the G/Mo series, as compared to the E/Mk lineages. Interestingly, cluster analysis indicates that miR expression in hematopoietic cells is sharply different from that observed in CB T lymphocytes. The lineage- and stage-specific pattern of miR expression is of functional relevance. As an example, transfection of miR 222 oligonucleotide into CD34+ cells grown in multilineage clonogenic culture causes a pronounced shift from E to GM colony formation, indicating modulation of the lineage commitment of hematopoietic progenitors. The target genes of miRs expressed in hematopoietic cells are often of pivotal functional significance, e.g., miR 222 targets the kit receptor (N. Felli et al., this Meeting). A single miR may target diverse mRNAs, e.g., miR 222 targets kit, Ets1 and Fli1. Conversely, a single mRNA may be targeted by different miRs, e.g., kit is targeted by miR 146, 221 and 222. Noterworthily, the miR expression pattern in primitive hematopoietic cells and their progeny is fully distinct from that observed in primitive mesenchymal and neural cells (i.e., “neurospheres”) and their progeny: this suggests that miR downmodulation during differentiation of primitive cells contributes to tissue-specific gene expression by unblocking translational repression of the target mRNAs.

Human Umbilical Cord Matrix Stem Cells: Preliminary Characterization and Effect of Transplantation in a Rodent Model of Parkinson's Disease

The umbilical cord contains an inexhaustible, noncontroversial source of stem cells for therapy. In the U.S., stem cells found in the umbilical cord are routinely placed into bio-hazardous waste after birth. Here, stem cells derived from human umbilical cord Wharton's Jelly, called umbilical cord matrix stem (UCMS) cells, are characterized. UCMS cells have several properties that make them of interest as a source of cells for therapeutic use. For example, they 1) can be isolated in large numbers, 2) are negative for CD34 and CD45, 3) grow robustly and can be frozen/thawed, 4) can be clonally expanded, and 5) can easily be engineered to express exogenous proteins. UCMS cells have genetic and surface markers of mesenchymal stem cells (positive for CD10, CD13, CD29, CD44, and CD90 and negative for CD14, CD33, CD56, CD31, CD34, CD45, and HLA-DR) and appear to be stable in terms of their surface marker expression in early passage (passages 4-8). Unlike traditional mesenchymal stem cells derived from adult bone marrow stromal cells, small populations of UCMS cells express endoglin (SH2, CD105) and CD49e at passage 8. UCMS cells express growth factors and angiogenic factors, suggesting that they may be used to treat neurodegenerative disease. To test the therapeutic value of UCMS cells, undifferentiated human UCMS cells were transplanted into the brains of hemiparkinsonian rats that were not immune-suppressed. UCMS cells ameliorated apomorphine-induced rotations in the pilot test. UCMS cells transplanted into normal rats did not produce brain tumors, rotational behavior, or a frank host immune rejection response. In summary, the umbilical cord matrix appears to be a rich, noncontroversial, and inexhaustible source of primitive mesenchymal stem cells.

The postnatal rat aorta contains pericyte progenitor cells that form spheroidal colonies in suspension culture

Pericytes play an important role in modulating angiogenesis, but the origin of these cells is poorly understood. To evaluate whether the mature vessel wall contains pericyte progenitor cells, nonendothelial mesenchymal cells isolated from the rat aorta were cultured in a serum-free medium optimized for stem cells. This method led to the isolation of anchorage-independent cells that proliferated slowly in suspension, forming spheroidal colonies. This process required basic fibroblast growth factor (bFGF) in the culture medium, because bFGF withdrawal caused the cells to attach to the culture dish and irreversibly lose their capacity to grow in suspension. Immunocytochemistry and RT-PCR analysis revealed the expression of the precursor cell markers CD34 and Tie-2 and the absence of endothelial cell markers (CD31 and endothelial nitric oxide synthase, eNOS) and smooth muscle cell markers (alpha-smooth muscle actin, alpha-SMA). In addition, spheroid-forming cells were positive for NG2, nestin, PDGF receptor (PDGFR)-alpha, and PDGFR-beta. Upon exposure to serum, these cells lost CD34 expression, acquired alpha-SMA, and attached to the culture dish. Returning these cells to serum-free medium failed to restore their original spheroid phenotype, suggesting terminal differentiation. When embedded in collagen gels, spheroid-forming cells rapidly migrated in response to PDGF-BB and became dendritic. Spheroid-forming cells cocultured in collagen with angiogenic outgrowths of rat aorta or isolated endothelial cells transformed into pericytes. These results demonstrate that the rat aorta contains primitive mesenchymal cells capable of pericyte differentiation. These immature cells may represent an important source of pericytes during angiogenesis in physiological and pathological processes. They may also provide a convenient supply of mural cells for vascular bioengineering applications.

Multiple intracranial subarachnoid osteomas

Intracranial osteomas, which have no connections with the dura or the skull, are very rare. Here we report one case of multiple intracranial subarachnoid osteomas. A 24-year-old gentleman, who had no previous history of systemic disease, meningitis or head injury, presented with a 6-month history of non-specific intermittent headache over the whole head. Neuro-imaging showed multiple ossified lesions in the right frontal area, which were found to compress the underlying cerebral hemisphere. The patient underwent a right frontal craniotomy. The masses were dissected from the depressed brain along the intact pial planes, however, all of the white bone-hard masses tightly adhered to the superficial cortical veins. The masses were removed and the cortical veins were sacrificed. The patient had headaches and was nauseous for three days after the surgery due to venous congestion; however, the patient was neurologically intact on discharge. Pathological diagnosis was osteoma. To our knowledge, this is the first report of multiple intracranial subarachnoid osteomas. Surgical findings strongly support the hypothesis of the origin of the tumour that the primitive mesenchymal cells from the connective tissue might have migrated into the subarachnoid space accompanying the intracerebral blood vessels.

Combined-type Osteosarcoma in a Rhesus Macaque

A femoral mass from a 15-year-old rhesus macaque was evaluated. Grossly, the mass consisted of a large, osteolytic focus in the distal femur, a gelatinous core of neoplastic tissue in the medullary cavity, and an invasive mass-obliterating musculature of the thigh. On histopathologic evaluation, three neoplastic mesenchymal cell populations, osteoblasts, fibroblasts, and primitive mesenchymal cells were identified. The mass was diagnosed as a combined type osteosarcoma. To our knowledge, this is the first osteosarcoma in a rhesus macaque with this subclassification.

A case of double cancer involving oral malignant melanoma and gastrointestinal stromal tumor (GIST)

We report a very rare case of double cancer involving palatal malignant melanoma and gastrointestinal stromal tumor (GIST), a rare tumor of the gastrointestinal tract originating from a primitive mesenchymal cell. After chemotherapy, radiation therapy, and treatment with interferon and OK-432, the GIST was resected and the melanoma disappeared. The patient has had no evidence of recurrent tumor, and the patient’s clinical course has been uneventful for 1 year. This is probably the first report of synchronous double cancer involving oral malignant melanoma and GIST.

Rhabdomyosarcoma: present and future perspectives in diagnosis and treatment

Rhabdomyosarcoma (RMS) is among the most common extracranial solid tumors occurring in children 1 . It is the commonest form of soft tissue sarcoma in children and young adults and accounts for approximately 4%-5% of all childhood malignancy with an annual incidence of 5.3 per million children under the age of 15 2 . The peak incidence is seen early in childhood with a median age at diagnosis of about 5 years. Males are reported to be more frequently affected than females. Because RMS is derived from primitive mesenchymal cells, it can be found virtually anywhere in the body, including those sites where striated muscles are not normally found. The most common primary sites are: genitourinary (24%), parameningeal (16%), extremities (19%), orbit (9%), other head and neck (10%), and miscellaneous other sites (22%) 3,4 .

Orbitotomy for retrobulbar malignant fibrous histiocytoma in a dog

A retrobulbar malignant fibrous histiocytoma was diagnosed in a 12-year-old castrated male Keeshond dog. The mass was excised with a lateral orbitotomy and zygomatic arch resection. Vision was preserved in the affected eye, and no recurrence was noted up to 10 months postoperatively. Malignant fibrous histiocytoma originates from primitive mesenchymal stem cells. The malignant fibrous histiocytoma seen in our patient was most consistent with the storiform-pleomorphic variant, given the storiform arrangement of spindle cells, the presence of histiocytoid cells, and a mixed inflammatory infiltrate, without giant cells. The metastatic potential of malignant fibrous histiocytoma in general, and the storiform variant in particular, is unknown. Seventeen months later the dog was presented to the referring veterinarian with anorexia, diarrhea, weight loss and bilateral purulent nasal exudates. The dog was euthanized without necropsy.

Nrf2 Expressed by Bone

Nuclear factor E2-related factor 2 (nrf2) is accepted as an important transcription factor in the regulation of many phase II detoxifying enzymes and oxidative-stress-inducible genes in many tissues including bone and cartilage. However, little attention has been paid to precise role of nrf2 on osteoblasts and chondrocytes. In the present study, we therefore investigated the role of nrf2 in the regulation of cell proliferation, differentiation and maturation using both MC3T3-E1 and ATDC5 cells. In MC3T3-E1 cells stably transfected with nrf2 (MC3T3-E1-nrf2 clone), the differentiation-dependent induction of alkaline phosphatase activity was significantly inhibited in addition to decrease of the mineralized matrix formation. Moreover, expression of mRNAs for osteocalcin and type I collagen was also markedly attenuated in MC3T3E1-nrf2 clone but not in MC3T3E1-empty vector clone. These inhibitory effect on cell differentiation was also observed in ATDC5 cells stably transfected with nrf2. Moreover, nrf2 significantly impaired the runx2-dependent enhancement of osteocalcin promoter activity. These data suggest that nrf2 may negatively regulate the differentiation of both osteoblasts and chondrocytes through inhibition of the runx2 dependent transcriptional activity. . These are bone-forming osteoblasts and bone-resorbing osteoclasts. The osteoblast lineage is derived from primitive multipotent mesenchymal stem cells with potentiality to differentiate into bone marrow stromal cells, chondrocytes, muscles and adipocytes 3) , while osteoclasts are multinucleated cells derived from the fusion of mononuclear hematopoietic precursors 4) . The development and differentiation of these two distinct cells are under the tight regulation by a number of transcription factors. Among them, Runx2, a cell-specific member of the Runt family of transcription factors, play a pivotal role in osteoblastic differentiation. Runx2 is the earliest and most specific molecular marker of the osteoblast lineage, its expression is both necessary and sufficient to induce osteoblast differentiation, and it regulates expression of most genes characteristic of the osteoblast phenotype 5,6,7)

Primary Cutaneous Carcinosarcoma (PCCS0 Aka Metaplastic Carcinoma)

We describe a case of PCCS in a 73 year‐old male who presented with a rapidly growing tumor of 6 months duration on the right ear. Clinical examination revealed a 5 × 4 × 4‐cm ulcerated, crusted, exophytic tumor on the superior aspect of the helix. Histologically, the mass revealed a biphasic tumor with malignant epithelial and mesenchymal components. The epithelial component consisted of a few foci of basal cell carcinoma (BCC). The majority of the tumor was composed of osteogenic sarcoma and malignant fibrous histiocytoma (MFH). An intricate transition of BCC into sarcoma was noted in a few foci. Atypical mitosis and necrosis were common. The BCC and tumor giant cells in the MFH area showed positive immunoreaction for cytokeratin and CD68 respectively. The tumor was negative for S‐100 protein, HMB‐45, muscle actins, chromogranin, and synaptophysin. In conclusion, a PCCS growing predominantly as osteosarcoma and MFH is reported. Although the exact histogenesis of PCCS is unknown, primitive mesenchymal cells of the dermis, surrounding the follicular units, are capable of pluripotent differentiation and are likely the source of origin of the sarcoma. The known aggressive biological behavior warrants wide excision and given the rare reports of metastasis and death, regular follow‐up is required

A Bone Marrow Population Containing Both Hematopoietic and Mesenchymal Stem Cells Constitutively Expressing Genes Pairs For: SDF1-CXCR4, CX3CL-CXCR1 and for VEGF Improves Vascularization When Implanted to Ischemic Legs.

The BM contains progenitor cells that give rise to hematopoietic tissue and also more primitive mesenchymal stem cells (MSC) which may differentiate into other tissues including endothelial cells. This potential of BM cells has already been employed in clinical studies suggesting that implantation of autologous BM cells may induce angiogenesis in ischemic tissues. In the present study 10 male pts with critical leg ischemia (41–64 yrs) suffering from pain at rest and/or foot ischemic ulceration (9/10 pts) with ABI (ankle/brachial index) <0.5 in 8/10 pts in whom surgical treatments were exhausted were enrolled in this study. 0.5L of BM obtained from the iliac posterior crest were processed in a Cobe Spectra 6.0 separator to remove RBC and to reduce the number of granulocytes. Fresh BM populations and those after processing were evaluated for phenotype characteristics and for the presence of transcripts for VEGF and for SDF1-CXCR4, CX3CL-CXCR1 gene pair expression. Usually 40 ml of cell suspensions were injected in 0.5 ml portions to ischemic muscles and the fate of the pts was evaluated in an out-pts observation setting for 5–7 mths. The number of WBC implanted was (mean±SEM) 30.2x108±4.5 which contained the following percentages of subpopulations CD34+ 1.58±0.25, CD45−CD34− 10.8±0.96, CD45−CD34−CD90+ 0.1±0.02, CD45−CD34−CD105+ 2.8±0.4, CD45−CD34−CD73+ 0.07±0.01 and 24 CFU-F/106 WBC. The positive effect of implantation was seen 2 days after the procedure with substantial pain reduction from 6.17±0.35 to 4.63±1.03 (p=0.04) 10 days and to 3.66±1.35 3 mths after implantation (p=0.034). ABI improved from 0.47±0.07 before to 0.66±0.06 (p=0.02) 10 days and to 0.66±0.07 (p=0.02) 3 mths after. This improvement was followed by ulceration healing in 5/9 pts (area of ulceration prior to implantation was 502.3±269.2 mm2 and 2 mths after was 32.3±23.6 mm2) in 2 pts ulceration healed completely. In 10 cases arteriography performed 3 mths after implantation documented new arteriole formation in 6 pts. The positive effect may not be long lasting in all pts as in 3/10 pts the pain at rest recurred and in 2 pts ulceration progressed 2 mths after implantation. The positive effect of the treatment could not be attributed to any of the described cell populations separately as evaluated by correlation analysis. In this study we identified cells with MSC characteristics in the BM population that were further enriched in MNC and implanted to ischemic muscles. In fresh BM cell populations and those after cell processing, the transcripts for VEGF and SDF1-CXCR4 and CXCL3-CXCR1 pairs were found. Implantation of these cells resulted in early, intermediate and late effects with pain relief, ischemic ulceration healing and finally arteriole length density, respectively. The pace of improvement suggested that the processed BM population while injected to ischemic muscles may act via cyto-/chemokine release with an analgetic effect and local immunity improvement. Furthermore, ulceration healing seen 10 days after implantation followed by neovascularization is likely due to auto/paracrine effects within a population of MSC that express genes facilitating the homing of vascular progenitors and play a role in new vessels formation. Supp by the grant PBZ-KBN-083/P05/2002 from the Polish State Committee Sci. Res.

Pathological changes of lungs in patients with severity acute respiratory syndrome

To evaluate the progression in morphologic changes of lungs in SARS patients. Four cases of SARS with lung tissue samples available (including one for ultrastructural examination) were enrolled into the study. Histochemical study for VG, Masson, reticulin, orcein, PAS, sirius red stains and immunohistochemical study for vimentin, desmin, smooth muscle actin, HHF-35, CD34, F8, collagen types I and III were also performed. According to the morphologic changes, lung lesions in SARS were subcategorized into 3 phases: acute exudative inflammation, fibrous proliferation and the final fibrotic stage. Two cases belonged to the acute exudative phase, in which the course was less than 20 days. The principal lesions consisted of acute alveolar exudative inflammation, hyperplasia of alveolar epithelium, necrosis, alveolar hyaline membrane formation, alveolar desquamation and focal fibroplasia. The acute exudative protein was PAS-positive. There was an increase in reticulin fiber formation. The reactive fibroblasts were highlighted by desmin and vimentin. One case belonged to the fibroproliferative stage, in which the course was around 25 days. Major lesions included proliferative interstitial pneumonia with early pulmonary fibrosis. There was also evidence of organizing pneumonia, with an increase in reticulin fiber formation, which had a glomeruloid appearance on special stain. The mesenchymal cells showed either myofibroblastic (which expressed desmin, HHF-35, smooth muscle actin and vimentin) or fibroblastic (which expressed vimentin only) differentiation. Fibroelastosis and fibroplasia was also noted. The remaining case belonged to the fibrotic stage, in which the course was around 75 days. The main features included diffuse fibrosis and honeycomb change, which were highlighted by sirius red stain. Immunohistochemistry showed mainly types I and IV collagen fibers. In all lesions, there was also an increase of number of CD68-positive macrophages. The morphologic progression in lungs of SARS patients is characterized by the development of increased fibrosis. The primitive mesenchymal cells, hyperplastic alveolar epithelial cells and macrophages play an important role in the pathogenesis.