Comparative analysis of trophoblasts and angiogenesis in human placental compartments / Análisis comparativo de trofoblastos y angiogénesis en compartimentos placentarios humanos

SUMMARY: Trophoblasts perform different functions depending on their location. This study aimed to obtain structural clues about the functions of villous and extravillous trophoblasts by using light and electron microscopy. Term placenta samples were obtained from 10 healthy pregnant women following cesarean sections. Frozen sections were stained with hematoxylin-eosin, semi- thin sections were stained with toluidine blue and examined with a light microscope, while thin sections were contrasted using uranyl acetate-lead citrate and evaluated under an electron microscope. Fine structural features of villous trophoblasts overlapped some villous stromal cells. In addition to the usual appearance of mature capillaries in villous stroma, we demonstrated and reported maturational stages of angiogenetic sprouts in term placenta. Extravillous trophoblasts were classified according to their location: fibrinoid, chorion, trophoblastic, column, maternal vascular endothelium, or decidua. All of these trophoblasts shared some ultrastructural features but also were distinct from each other. In decidua, it was noted that the endothelial lining of some vessels was invaded by a few endovascular trophoblasts with irregular microvilli. These cells shared some ultrastructural properties with both villous trophoblasts and stromal cells. Examination showed that angiogenesis was still present in term placentas and that trophoblasts, endothelial and stromal cells have very similar properties ultrastructurally, suggesting they represent transformational forms.

RESUMEN: Los trofoblastos dependiendo de su ubicación realizan diferentes funciones. Este estudio tuvo como objetivo obtener pistas estructurales sobre las funciones de los trofoblastos vellosos y extravellosos mediante el uso de microscopía óptica y electrónica. Se obtuvieron muestras de placenta a término de 10 mujeres embarazadas sanas después de cesáreas. Las secciones congeladas se tiñeron con hematoxilina-eosina, las secciones semidelgadas se tiñeron con azul de toluidina y se examinaron con un microscopio óptico, mientras que las secciones delgadas se contrastaron con acetato de uranilo-citrato de plomo y se evaluaron con un microscopio electrónico. Las finas características estructurales de los trofoblastos vellosos se superponen a algunas células estromales vellosas. Además de la apariencia habitual de capilares maduros en el estroma velloso, demostramos e informamos etapas de maduración de brotes angiogenéticos en la placenta a término. Los trofoblastos extravellosos se clasificaron según su localización: fibrinoide, corion, trofoblástico, columna, endotelio vascular materno o decidua. Todos estos trofoblastos compartían algunas características ultraestructurales, pero también eran distintos entre sí. En decidua se observó que el revestimiento endotelial de algunos vasos estaba invadido por unos pocos trofoblastos endovasculares con microvellosidades irregulares. Estas células compartían algunas propiedades ultraestructurales tanto con los trofoblastos vellosos como con las células del estroma. El examen mostró que la angiogénesis todavía estaba presente en las placentas a término y que los trofoblastos, las células endoteliales y estromales tienen propiedades ultraestructurales muy similares, lo que sugiere que representan formas de transformación.

Antiproliferative and Mitochondrial Protective Effects of Apigenin in an Oxygen-Induced Retinopathy In Vivo Mouse Model.

Purpose: To investigate the effects of a common dietary flavonoid apigenin on retinal endothelial cell proliferation, retinal morphological structure, and apoptotic cell death in an oxygen-induced retinopathy (OIR) mouse model to evaluate the possibility of the use of apigenin in the treatment of ocular neovascular diseases (ONDs). Methods: Ninety-six newborn C57BL/6J mice were included. Eight groups were randomized, each including 12 mice. Two negative control groups were kept in room air: the first without any injection and the second received intravitreal (IV) dimethyl sulfoxide (DMSO), which is the solvent we used. The OIR groups were exposed to 75% ± 2% oxygen from postnatal days (PD) 7 to 12. On PD 12, the mice were randomly assigned to 6 groups: 2 OIR control groups (1 received no injection, 1 received IV-DMSO), 2 IV-apigenin groups (10 and 20 µg/mL), and 2 intraperitoneal (IP)-apigenin groups (10 and 20 mg/kg). We quantified retinal endothelial cell proliferation by counting neovascular tufts in cross-sections and examined histological and ultrastructural changes through light and electron microscopy. We evaluated apoptosis by terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL). Results: We detected a significant increase in endothelial cell proliferation in the OIR groups. Groups receiving apigenin, both IP and IV, had significant decreases in endothelial cells, atypical mitochondrion count, and apoptotic cells compared with the groups receiving no injections. None of the apigenin-injected groups revealed cystic degeneration or cell loss. Conclusions: Apigenin suppresses neovascularization, has antiapoptotic and antioxidative effects in an OIR mouse model, and can be considered a promising agent for treating OND. Clinical trial (Project number: DA15/19).

Antiproliferative and anti-apoptotic effect of astaxanthin in an oxygen-induced retinopathy mouse model.

OBJECTIVE: To evaluate the impact of intravitreal (IV) and intraperitoneal (IP) astaxanthin (AST) injections on neovascular development (ND), retinal morphology, and apoptotic activity in a C57BL/6J mouse model with hyperoxia-induced retinopathy (HIR). DESIGN: C57BL/6J mouse model. METHODS: Two negative control groups (n = 6 each; one of which received IV sterile dimethyl sulfoxide [DMSO]) of C57BL/6J-type mice were exposed to room air. The HIR groups included 36 C57BL/6J-type mice exposed to 75% ± 2% oxygen from postnatal day (PD) 7 to PD 12. On PD 12, these mice were randomized into 6 groups (n = 6 each): 2 HIR control groups (one of which received IV-DMSO), 2 IV-AST groups (10 and 100 µg/mL), and 2 IP-AST groups (0.5 and 5 mg/kg). We measured ND by counting neovascular tufts in cross sections and examined histological, ultrastructural changes via light and electron microscopy. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated nick end-labeling. RESULTS: No ND was detected in the negative control groups. ND levels were not significantly different between high- and low-dose AST for either means of administration. However, ND levels were significantly lower in the AST groups, regardless of delivery, compared to the control groups. The means of delivery (IP versus IV) also yielded significant differences in ND. The incidence of mitochondrial dysmorphology and apoptosis were lower in groups receiving AST. CONCLUSIONS: AST seems to suppress ND and has anti-apoptotic activity in the HIR mouse model.

Implications for thymus growth in childhood: histogenesis of cortex and medulla.

The increase in autoimmune diseases in recent years has drawn attention back to the thymus, with new approaches to improve and/or restore immune function being investigated. As the primary lymphoid organ responsible for functional T cell development, studies on the pre-/post-natal development of this organ and T lymphocytes in human and other species are of special interest. During our screening studies we observed structures that had not been described or mentioned previously, and named them "epitheliostromal sheaths". Associated with these unique structures were also small attached lobules (possibly reflecting the maturational stages of thymic lobules), which the authors consider as markers of histogenesis and the growth of the organ during early childhood; these findings are thus presented to researchers in this field. Approximately 1000 sections prepared from infantile thymic tissues of partial biopsy specimens were immunostained and examined. Specimens were taken from ten patients (with informed consent) in the age range of 4-9 years who underwent surgery due to congenital cardiovascular anomalies but were otherwise normal. Digital images of interest were captured to describe them in detail. Determining the immunophenotype of the compartments in these newly developing lobules assisted us greatly in defining compartments and their growth order. In summary, our findings suggest a niche-based thymus growth mechanism during childhood. We presented our findings, hoping to provide additional insight to researchers aiming to restore thymus function in adulthood and improve its immunological functions.

Effect of Creatine on Rat Sciatic Nerve Injury: A Comparative Ultrastructural Study.

AIM: Creatine is an endogenous molecule synthesized in the liver, kidney and pancreas from glycine and arginine and is important for mitochondrial metabolism. It is widely used as a supplement for improving muscle mass and function for many years. As it is expected to prevent apoptosis and diminish oxidative stress, it is also studied in a number of neurodegenerative diseases for its beneficial effect in recent years. We studied the effect of creatine on the peripheral nerve injury in an experimental rat crush injury model to obtain ultrastructural evidence. MATERIAL AND METHODS: Animals were randomly divided into 3 groups having 5 animals in each group. Group 1 was the control group, Group 2 the trauma group and Group 3 the trauma+creatine group. The first group served as sham control. In group 2 and group 3, sciatic nerves of the rats received crush injury using aneurysm clips. In group 3, daily 2 g/kg creatine monohydrate was administered via gavage after the trauma. Nerve samples were obtained at the 28th day after trauma for light and electron microscopic evaluation. RESULTS: Our comparative analysis results suggest a possible positive effect of creatine supplement on peripheral nerve regeneration as statistical analysis revealed significant differences between group 2 and group 3. Though our finding does not represent a miracle of regenerative support, beneficial usage of creatine is documented in the present study. CONCLUSION: Creatine supplement helps to diminish the harmful effects of peripheral nerve crush injury which is also supported by electron microscopy findings.

Structural consequences after intravitreal bevacizumab injection without increasing apoptotic cell death in a retinopathy of prematurity mouse model.

PURPOSE: To evaluate the effect of different bevacizumab concentrations on retinal endothelial cell proliferation, retinal structures and apoptotic activity after intravitreal injection in a retinopathy of prematurity (ROP) mouse model. METHODS: A total of 35 of C57BL/J6 mice were exposed to 75±2% oxygen from postnatal day 7 to postnatal day 12. On day 12, 10 mice (group C) were injected with 2.5 µg intravitreal bevacizumab (IVB), 11 mice (group D) were injected with 1.25 µg IVB, and 14 mice (group E) were injected with 0.625 µg IVB in one eye. The contralateral eyes were injected with isotonic saline (control group=group B). Four nonexposed mice served as negative controls (group A). Neovascularization was quantified by counting the endothelial cell proliferation on the vitreal side of the inner limiting membrane of the retina. Histological and ultrastructural changes were examined by light and electron microscopy. Terminal deoxynucleotidyl transferase deoxy-UTP-nick end labelling (TUNEL) was used to detect apoptosis. RESULTS: The endothelial cell count per histological section was lower in groups C (p<0.0001), D (p<0.0001) and E (p<0.0001) compared with the control group B. Histological evaluation showed no retinal toxicity in any group. Electron microscopy revealed hyperoxia-induced mitochondrial dysmorphology in group B. Mitochondrial dysmorphology displayed dose-dependent gradual increase in IVB-injected eyes. Intravitreal bevacizumab induced no significant increase in apoptotic cell death. CONCLUSION: Bevacizumab suppresses endothelial cell proliferation in a ROP mouse model. In addition to hyperoxia-induced mitochondrial dysmorphology of C57BL/J6 retina, morphological findings implicate further mitochondrial vulnerability because of bevacizumab without increase in apoptotic cell death.

Distribution of inflammatory cells, adhesion molecules, intermediate filaments, and chemokine receptors in subgroups of nasal polyp patients.

BACKGROUND: The pathogenesis of nasal polyps (NPs) is incompletely understood. The aim of this study was to investigate the distribution of inflammatory cells, adhesion molecules, intermediate filaments, and chemokine receptors in subgroups of NP patients. METHODS: In total, 35 patients were enrolled (group 1, 10 patients with Samter syndrome; group 2, 10 patients with diffuse polyposis without signs of Samter syndrome; group 3: 5 patients with solitary nasal polyps; group 4, 10 controls). Immunohistochemical staining was performed for CD105, CD106, CD62E, CD4, CD8, CXCR4, CD147, CD90, CD104, BF45, vimentin, pancytokeratin, and muscle-specific actin (MSA) in all patients' specimens. RESULTS: Expression of CD4, CD8, and CD106 were similar between the groups. Number of patients expressing CD4 in groups 1, 2, and 3 were higher than the controls. Number of patients expressing CD8 antigen were significantly higher in all three groups than in the control group. Expression of CD147 in groups 3 and 4 was significantly higher than in groups 1 and 2. CD98 expression was higher in groups 1, 2, and 3 than in group 4. The number of patients expressing vimentin in groups 1, 2, and 3 was significantly higher than in group 4. Immunostaining for pancytokeratin was positive in all patients. CONCLUSION: In conclusion, inflammatory cell, adhesion molecule, intermediate filament, and chemokine receptor profiles in nasal polyps differ among different patient groups and control subjects. Additional specific immunohistochemical studies are necessary for development of more specific immunotherapies.

Targeting novel antigens in the arterial wall in thromboangiitis obliterans.

Thromboangiitis obliterans is an inflammatory disease possibly resulting from cigarette smoking as a primary etiologic factor, perhaps as a delayed type of hypersensitivity or toxic angiitis. As little is known about the pathogenesis of the disease, we aimed to determine novel antigens that might be responsible from the local inflammatory reactions and structural changes observed in this disease. An indirect immunoperoxidase technique is used to examine the tissue samples obtained from the dorsalis pedis artery of affected individuals with twenty monoclonal antibodies. Among these several antigens which are not previously reported in TAO like CD34, CD44 and CD90 were determined in the tissue samples examined. On the other hand, many other antigens like cytokine/chemokine receptors, several enzymes and leukocyte/lymphocyte antigens were lacking giving some clues about the local pathological reactions. We briefly discussed our findings for several critical antigens those first described in the present work, possibly having roles in the development of the disease. Expression of the CD90/CD11c receptor/ligand pair seems to play an important role in mononuclear cell recruitment to the damage site. Vascular invasion of not only tunica intima but also the tunica media in affected vessels is clearly demonstrated using endothelial cell specific antigens.

Immunohistochemical analysis of small plaque parapsoriasis: involvement of dendritic cells.

Small plaque parapsoriasis (SPP) is one of the cutaneous T-cell lymphoproliferative disorders. The aim of the present study was to show the antigenic profile of a subset of dendritic cells and lymphocytes in SPP in comparison with normal cells to provide data on the role of these two cell types in the pathogenesis of SPP. Skin biopsy specimens of lesions were obtained from 8 patients with SPP. Biopsies of the healthy skin from 9 control individuals were also analyzed. Immunohistochemistry was performed on the frozen tissue sections to reveal binding of anti-HLA Class II, anti-CD1a, anti-CD4, anti-CD8, anti-CD44, anti-CD45, and anti-CD68 monoclonal antibodies. There was a statistically significant increase in the number of CD1a(+), Langerhans cells (LCs), HLA-DR-immunoreactive and, CD1a-positive dermal dendritic cells and CD68(+) macrophages in the SPP group (p=0.008, 0.008, 0.002 and <0.0009, respectively). The number of lymphocytes positive for CD4, CD8 and CD45 was significantly higher than normal in the SPP group (p=0.015, <0.0009 and <0.0009, respectively). Our study demonstrates that both peptide- and lipid-based antigens are involved in the persistent antigenic exposure in SPP. Dendritic cells play a pivotal role in SPP by presenting antigens by both LC and dermal dendritic cells via MHC Class II and CD1a molecules. The CD68(+) macrophages are thought to be involved in the immune response in this pathology as an antigen-presenting cell.

Pathogenesis-related adhesion molecules in Henoch-Schonlein vasculitis.

The aim of this study was to reveal the distribution of various inflammation and endothelium-related adhesion molecules, namely, P-selectin, E-selectin, ICAM-1, ICAM-2, ICAM-3 and VCAM-1, on the skin samples of patients with Henoch-Schonlein purpura. Skin biopsies obtained from 12 pediatric patients at the acute purpura phase and from 5 patients at the convalescent phase of the disease were included in the study. Endothelial expression of P-selectin (P < 0.05), endothelial and inflammatory cellular expressions of ICAM-2 (P < 0.05, P < 0.01) and inflammatory cellular expression of ICAM-3 (P < 0.05) were significantly more intense when compared to patients in the convalescent phase. Although endothelial E-selectin and VCAM-1 expressions, and endothelial and inflammatory cellular ICAM-1 expressions displayed a decrease in the convalesant phase, this difference was not found to be statistically significant (P > 0.05).

Platelet-rich plasma and bone healing: a histologic study in titanium bone chambers.

The potential benefits of platelet-rich plasma in the healing of isolated defects are unclear. The purpose of this study was to evaluate the effects of PRP on bone healing in titanium bone chambers, which represented isolated defects. PRP was prepared from blood collected from six adult female albino New Zealand rabbits. Titanium bone chambers with a 4-mm inner diameter were implanted into the tibiae of each animal at baseline and 2 weeks later; chambers healed for 6 or 8 weeks, either with PRP (test) or without PRP (control). Bone chambers were harvested from each animal and processed for histologic evaluation. Bone formation in 8-week test samples was not significantly different from that of the 6-week test samples. In control samples, more bone formation was seen at 8 weeks than at 6 weeks. The fibrous tissue content in control samples was higher than that of the test group in superficial sections, revealing that the tissue differentiation rate was higher in the test chambers. Time-dependent bone tissue differentiation in bone chambers augmented with PRP is higher than in normal wound healing, and PRP seems to increase the rate of tissue differentiation in early healing.

Primary stability of simultaneously placed dental implants in extraoral donor graft sites: a human cadaver study.

PURPOSE: To compare the primary stability of dental implants placed in fibula, iliac crest, and scapula of human cadavers. MATERIALS AND METHODS: Straumann Dental Implants (Institut Straumann, Basel, Switzerland) 4.1 mmx10 mm in diameter were placed into bilateral fibula, iliac crest, and scapula of 4 fresh human cadavers. For the assessment of primary stability of implants, installation torque values (ITV) and removal torque values (RTV) were measured using a custom-made strain-gauged torque wrench, and resonance frequency analysis was carried out to quantify the implant stability quotients (ISQ). Bone specimens from each donor site were harvested to perform radiographic and histomorphometric analyses. Linear distance and optical density (OD) measurements were made on digitized parallel periapical radiographs and bone area fraction (BAF) was calculated on digitized images of decalcified histologic sections. RESULTS: Fibula donor site presented higher ITVs and RTVs and cortical bone height for implants than other sites (P<.05). BAF measurements for iliac crest were higher than fibula and scapula bone donor sites. OD was higher in the iliac crest followed by scapula and fibula. CONCLUSION: The primary mechanical stability of implants placed in the fibula is higher than those placed in the iliac crest and the scapula, although the bone mass and density around implants in latter sites are higher.

Activation antigens during the proliferative and secretory phases of endometrium and early-pregnancy decidua.

BACKGROUND: Clarifying the normal distribution of activation antigens will contribute to database construction studies of monoclonal-antibody-based therapies in endometrial disorders. METHODS: In this study, endometrial tissue samples obtained during proliferative and secretory phases and decidual samples of early pregnancies were immunostained by the monoclonal antibodies anti-CD26, anti-CD30, anti-CD70, anti-CD71, and anti-CD98 using the indirect immunoperoxidase method. RESULTS: CD26 is expressed on the glandular epithelium in the endometrium and decidua. Endothelial CD26 is expressed less in the decidua when compared to the endometrium. CD30 is strongly expressed by decidual cells. It is only weakly expressed on endometrial and decidual vessels. Glandular and endothelial CD70 expression is mainly seen in the proliferative phase of the menstrual cycle. Glandular CD71 expression is less in the decidua when compared to the endometrium. Its expression on stromal cells is more in the secretory phase of the menstrual cycle and in early pregnancy deciduae. It is expressed on endometrial vessels but not on decidual vessels. Glandular CD98 is expressed more in the decidua when compared to the endometrium. This antigen exists on endometrial lymphocytes. It is strongly expressed on the endothelium in the endometrium and decidua. CONCLUSION: It seems that CD26 and CD70 are not involved in the functions of endometrial and decidual stromal cells. CD30 and CD71 are thought to be involved in decidualization. Absence of activation antigens other than CD98 on lymphocytes indicated an antigenic profile for large granular lymphocytes that is different from regular lymphocytes.

The HLDA8 blind panel: findings and conclusions.

There were over 600 antibodies submitted to HLDA8, with many of unknown specificity. Of these, 101 antibodies were selected for a blind panel study that also included 5 negative controls and 27 positive controls of known CD specificity making a total of 133 antibodies in the final panel. Of the 101 unknowns, 31 antibodies were identified during the course of this blind panel study as being specific for known molecules and included some specific for MHC class II antigens, CD45 isoforms and the Dombrock antigen. Several antibody pairs among those in the blind panel were found to have very similar staining patterns and were therefore compared by immunohistochemical and/or Western blot analyses for identity.

Immunohistological analysis of normal and osteoarthritic human synovial tissue.

Intercellular communication mediated by cell surface antigens is important in the maintenance of synovial tissue (ST) integrity. Chronic inflammation is a common feature of osteoarthritis (OA). Cellular attachment to and migration into ST is one of the critical aspects of chronic inflammation. This study was undertaken to examine the tissue distribution of a broad spectrum of monoclonal antibodies (mAbs) containing tetraspan antigens (CD9, CD63, CD151), endothelial cell antigens (CD31, CD36, CD105, CD106, CD146), integrins (CD49a-f, CD29, CD41, CD51, CD61), CD39, CD98, CD99, CD143 and, CD147 supplied from fifth and sixth international workshops and conferences on human leukocyte differentiation antigens in a comparative manner in human OA and normal synovium. Ten primary OA patients and six normal individuals were included in this study. The average age of the patients was 65.0 +/- 8.3 years and the average age of the controls was 31.8 +/- 5.3 years. Sections were screened using an indirect immunoperoxidase method. Tetraspan antigens and CD98 presented rather unique staining pattern in OA synovium suggesting special roles for each antigen on the synovial lining layer (SLL). Endothelial cells and type A synoviocytes expressed CD31 and CD36 in OA, but only endothelium in normal subjects. Integrins presented a uniform staining pattern in both groups. There was a positive reaction in some of the ST stromal elements for CD143 in all specimens. In conclusion, human normal and OA synovium were comparatively reviewed by a broad spectrum of mAbs with special attention being given to their functional aspects. This data suggests a significant difference in antigenic phenotype of SLL cells in OA and ST not to be considered at a normal-like state in OA. The fact that their activation was independent of the degree of lymphocyte infiltration further emphasizes the possible central importance of SLL.

Fibroblastic reticular cells and fibroblast-like cells determined by monoclonal antibodies B-F45 and B-D46 in humans.

OBJECTIVE: Identification of stromal microenvironmental components of lymphoid organs is relatively harder at light microscopic level as few markers, which are mostly not very specific, are available to be used for such a purpose. We screened a large panel to determine monoclonal antibodies (mAbs) those reactive with fibroblasts/fibroblast-like cells aiming to obtain further evidence for the organization and function of this cell group. METHODS: Tissue samples of forty patients undergoing surgery in Otorhinolaryngology, Obstetrics and Gynecology, Orthopedics and Traumatology, Cardiovascular Surgery and General Surgery Departments, Hacettepe University Medical Faculty Hospital, Ankara, Turkey, due to different pathologies obtained as partial specimens of surgery which were apart from pathological examination were immunostained by indirect immunoperoxidase method in histology and embryology department in 2003. RESULTS: Among the screened monoclonal antibodies, monoclonal antibodies B-F45 and B-D46 reacted with the members of the family, therefore examined in detail in available human organs. Among the unique staining patterns of these mAbs, reactivity on fibroblastic reticular cells, perineural sheet cells pericryptal/perivillous fibroblasts were striking. CONCLUSION: Both mAbs will provide useful tools for further studies on stromal network of peripheral lymphoid organs and peripheral nerves.

Structural and immunophenotypic characterization of high endothelial venules in rat and human tissue.

OBJECTIVE: To present additional data on high endothelial venule (HEV) structure and immunophenotype. METHODS: We used the zinc iodide-osmium tetroxide technique (ZIO), which is a metallophilic fixation and staining technique to examine HEVs at light and electron microscopic levels as this technique was previously reported to be reactive with cells in HEVs. Tonsils and lymph nodes were obtained from the Surgery and Otorhinolaryngology Departments, Hacettepe University Hospital, Ankara, Turkey during 2002 and 2003. An indirect immunohistochemical technique was used to examine frozen human tissue samples. RESULTS: Organelle rich high endothelial cells, sheet-like processes of pericytes surrounding HEVs, structural relation of pericyte processes with fibroblastic reticular cells, an unusual multivesicular body-like organelle within high endothelial cells were presented. Expression of a large panel of defined and yet non-defined antigens on HEVs are also presented using an indirect immunoperoxidase technique. CONCLUSION: Presence of some of these antigens on HEVs was previously reported while no previous report is available for others. Significance of the expression of these antigens in HEVs, structural hints for trans endothelial migration of lymphocytes and their travel along the reticular cell meshwork is briefly discussed.

Light and electron microscopic examination of human subungual tissue. Glomus and lamellated bodies.

OBJECTIVE: There is only limited data related to the subungual glomus body. We therefore studied the structure of this organ, aiming to obtain further evidence. Additionally, we encountered undefined receptor like structures in close association with these glomus cells, named them as lamellated bodies and examined both of the structures at light and electron microscopic levels. METHODS: This study was carried out at the Faculty of Medicine, Hacettepe University, Ankara, Turkey, during the time period May 2001 to March 2002. In this study, the subungual tissues of 4 patients were examined. RESULTS: Within subungual tissue, 2 groups of morphologically significant structures were determined by light microscopy. The first structure was described as glomus body. It was characterized as an encapsulated structure, rich in rounded clear cells filling its central compartment. The latter structure having a lamellated appearance was described as lamellated body. In the electron microscopic examination, lamellated bodies were characterized by central filament rich large cells and surrounding cytoplasmic processes of ensheathing cells, some of which were vacuolated. Glomus bodies were surrounded by a capsule and centrally located numerous rounded cells which reflected the structural features of an active cell. CONCLUSION: The lamellated bodies are very unusual structures and they are not found in any other part of the body. The structural organization of the ensheathing cells in the lamellated bodies greatly resembles many skin associated receptors. Therefore, we planned future studies by using immunohistochemistry, to reveal nervous elements for structural contribution.

Antigenic profile of human thymus in concurrence with "Clusters of Thymic Epithelial Staining" classification.

We examined the expression of various CD coded or not yet defined antigens in human thymus samples using indirect immunoperoxidase and immunoflourescent techniques. Data obtained are presented in concurrence with Clusters of Thymic Epithelial Staining (CTES) classification for various monoclonal antibodies recognizing CD antigens (CD1, CD1a, CD6, CD9, CD14, CD16, CD29, CD30, CD32, CD44, CD45RB, CD47, CD48, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD51, CD53, CD54, CD56, CD57, CD63, CD85, CD95, CD98, CD102, CD103, CD106, CD109, CD146, CD147, CD148, CD151, CD152, CD158a, CD158b, CD164, CD165, CD166) and for monoclonal antibodies 1B10, 5G7, A4, BD46, BLTZ, HP1C5, IND.64, M72, WU947 whose specifities are not yet defined. Some of the mAbs such as CD49f, IND.64 and BD46 are detected as good markers for specific cell types or compartments. Significance of the presence of these antigens on thymic epithelial cells at certain locations is briefly discussed.