Myelin Ultrastructure Terminology in Disease and Recovery Processes.

Ultrastructural evaluation of myelin coat helps to understand the possible background of pathological changes leading to deterioration or complete loss of nerve functions. A number of terms were previously introduced to describe the fine structural changes in myelin under various conditions. We believe that using a common terminology will be helpful to interpret the structure/function relationship in neurological disorders empowering the diagnosis and possible therapeutical approaches. In this paper, we present examples of ultrastructural changes in myelin during myelination, demyelination, re-myelination and dysmyelination processes and we reviewed the terminology previously used.We tried to include all studies reporting ultrastructural findings with no limitation to the experimental conditions, the species used and the disorders. The terminology used to describe the structural findings included compacted myelin, partially compacted myelin, noncompacted myelin, redundancy (hypermyelination, tomacula, myelinosome), splitting, complete circular splitting, myelin degradation, concentric lamellar bodies (myelin figures), loss of myelin lamellae, polyaxonal Schwann cells and necrotic cell debris.Ultrastructural data described in this paper aimed to provide a guide for future studies. We concluded that the evaluation of ultrastructural changes in any neurological disorder is greatly valuable for a better understanding of pathological and physiological changes occured. We also believe that supporting the ultrastructural findings with quantitative methods in the future will be of great value.

Effects of alendronate and pamidronate on apoptosis and cell proliferation in cultured primary human gingival fibroblasts.

Data arising from the recent literature directed the researchers to study on the degree and extent of bisphosphonate toxicity on oral mucosa in further detail. The aim of this study is to determine the half maximal inhibitory concentration of pamidronate (PAM) and alendronate (ALN) on human gingival fibroblasts in vitro using 3-[4.5-thiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) assay and to evaluate the effects of both agents on the proliferation and apoptotic indices. Cells used in the study were generated from human gingival specimens and divided into alendronate (n = 240), PAM (n = 240), and control groups (n = 60). Based on the MTT assay results, 10(-4), 10(-5), 10(-6), and 10(-7) M concentrations of both drugs were administered and the effects were evaluated for 6, 12, 24, 48, or 72 h periods. An indirect immunofluorescence technique was used to evaluate apoptotic (anti-caspase 3) and proliferation (anti-Ki67) indices. Toxicity of both PAM and ALN was found to be the most potent at 10(-4)-10(-5) M range. The apoptotic index of PAM group was found to be significantly higher than ALN group for all concentrations especially at 24 h incubation time (p < 0.05). The decrease in the proliferation index was found similar in first 48 h for both drugs; however, after 72 h of incubation decrease in proliferation index in PAM group was found to be significantly higher (p < 0.05). Micromolar concentrations of not only PAM but also ALN rapidly affect cells generated from human oral gingival tissue by inducing apoptosis together with inhibition of proliferation. Cytotoxic effects of both ALN and PAM on primary human gingival fibroblasts, which cause significant changes in apoptotic and proliferative indices as shown in this in vitro study, suggests that the defective epithelialization of oral mucosa is possibly a major factor on the onset of bisphosphonate-related osteonecrosis of the jaw cases.

Effect of prostaglandin E-1 on Wisconsin University and histidine-tryptophan-ketoglutarate preservation solutions on preservation injury of the perfused liver.

BACKGROUND: The aim of this study was to investigate the effects of prostaglandin E-1 (PGE-1) on preservation injury in livers perfused with the University of Wisconsin (UW) or histidine-tryptophan-ketoglutarate (HTK) solutions. MATERIALS AND METHODS: Five groups each including six rats included. Ringer's lactate RL (group 1), HTK (group 2), HTK + PGE-1 (group 3), UW (group 4), or UW PGE-1 (group 5). Liver tissue and preservation fluid samples were obtained from the perfused lives for pathological and biochemical examinations respectively at 0, 6 and 12 hours. RESULTS: Upon biochemical examination, aspartate aminotrasnferase and alanine aminotransferase values were highest among the group with RL solution and lowest with PGE-1. Liver structure was found to be damaged immediately after RL solution, whereas it was preserved in the other four groups. Fewer cellular changes were reported at the end of 12 hours in the groups administered PGE-1 compared with the other groups. CONCLUSIONS: PGE-1 when applied before preservation protected liver functions, decreased pathologic injury, and delayed changes that occur under cold ischemic conditions.

Education to reduce potassium levels in adolescent, haemodialysis patients.

A semi-experimental survey was carried out. The aims included assessing how knowledgeable adolescents undergoing haemodialysis treatment were regarding hyperkalaemia, and determining how effective an education programme in preventing hyperkalaemia would be. 31 volunteers (twelve girls and nineteen boys), who had two or three haemodialysis treatments a week, were included in the study. Data were obtained through a questionnaire, the answers to which were written down for each participant separately by the researcher. A manual was prepared with the aim of educating children in hyperkalaemia, the participants were taught lessons in groups of two to three at a time. The education programme was completed in eight sessions. At the end of the programme each participant was given a copy of the manual. A month after the education programme, participants were asked to refill the section of the aforesaid questionnaire. The scores in this section had increased, and blood potassium levels had significantly decreased (p = 0.02).

Immunophenotypic analysis of human spleen compartments.

Microanatomical compartments of the human spleen are yet under evaluation as most of the present information comes from experiments on animals with different anatomical structures. Immune staining of stromal and blood-born cells by cell surface antigens facilitates the differentiation of functional microanatomical compartmentalization of immune organs, including the spleen. Twenty-two specimens from healthy adult subjects with the average age of 35.6 +/- 13.8 (Range 17 to 58) years were included in this study. Monoclonal antibodies used in this study were supplied from the 5th, 6th and 7th International Workshops and Conferences on Human Leukocyte Differentiation Antigens. Tetraspan antigens presented a rather unique staining pattern in the human spleen, suggesting special roles for each (CD9, CD53, CD63, CD151 and CD231) in certain locations. Sinus lining cells presented a distinctive antigenic profile, sharing both endothelial cell (CD31, CD36, CD54, CD62P, CD102, CD105, CD106 and CD146) and macrophage lineage characteristics. The sheathed capillaries were not restricted to the perifollicular zone alone. Extracellular matrix receptors (CD49 a, CD49 b, CD49 c, CD49 e, CD49f, CD29 and CD44) stained the penicillary arterioles and vascular smooth muscle. These molecules were also found on the vascular endothelium. Leukocyte antigens (CD11a, CD11b, CD22, CD43, CD45, CD45RB, CD45RO and CD50) were mainly expressed in the white and red pulp of the spleen at different intensities, excluding the penicillary arterioles. Activation antigens (CD26, CD71 and CD98) presented a diffuse and broad staining pattern. In conclusion, microanatomical compartmentalization, microcirculation and function of the human spleen were evaluated using a wide panel of monoclonal antibodies.

Three-dimensional (3-D) reconstruction of the human coccygeal body.

The three-dimensional reconstructions of the human coccygeal bodies were undertaken using semi-thin serial sections which were cut from the tissue specimens taken from the ventral parts of the tip of the coccyges of four patients. The coccygeal bodies were observed in the form of convoluted, irregular helical tubes. The diameters of the coccygeal bodies in serial sections were measured and a statistical analysis performed. The lumens of the coccygeal bodies were not observed in the twisted parts of the tissue specimens. Depending upon to the irregular courses of the lumens and their lack of appearances in the twisted areas, we are unable to show the three-dimensional reconstructions of the lumens of the coccygeal bodies. In conclusion, this is the first study reporting the three-dimensional reconstruction of the contours of the coccygeal body. These type of studies, which were done by using serial sections will be very helpful for the understanding of the little known organs of the human body.

Neural cell adhesion molecule and neurothelin expression in human ameloblastoma.

PURPOSE: The objective of the present study was to determine whether neural cell adhesion molecules (NCAM; CD56) and neurothelin (CD147) are expressed by adontogenic cells in the ameloblastoma. MATERIALS AND METHODS: Frozen sections from ameloblastoma specimens (n = 7) were stained with monoclonal antibody-recognizing CD56 and CD147 molecules using indirect immunoperoxidase and indirect immunofluorescent techniques. RESULTS: CD56 and CD147 molecules were strongly expressed by the peripheral columnar cells of the tumor nests. Neurothelin reactivity was also present in the stellate reticulum of the nests and in some stromal components. CONCLUSIONS: The presence of these antigens in ameloblastoma supports the classic view about the neural crest origin of cells giving use to this tumor.

Changes in bladder of rabbits subjected to elevation of intraabdominal pressures.

BACKGROUND/PURPOSE: An experimental study has been conducted to evaluate the effects of increased intraabdominal pressure (IAP) on the morphology of the bladder of rabbits. METHODS: Experiments were performed on 20 adult male New Zealand rabbits. Six rabbits served as the control group (group I). Seven rabbits were subjected to increased IAP of 7 cm H2O for 10 days through installing air into the abdominal cavity (group II). Increased IAP was maintained for 60 days in another group of 7 rabbits (group III). Bladders were removed and fixed in 10% formalin for routine process. Paraffin sections of 5 to 7 microm were stained with H & E for light microscopic evaluation. Histopathologic parameters were scored, and the mean scores according to groups were compared by 1-way analysis of variance (ANOVA). The mean values of groups were compared separately by Tukey-Kramer multiple comparison test. In these tests, P value less than.05 was considered statistically significant. RESULTS: All of the bladder strips obtained from animals subjected to 10 days of pressure increase (group II) showed mild to severe degree of vacuolation and desquamation of urothelium. Both vacuolation and desquamation of urothelium were present in all of the strips obtained from rabbits with 60 days pressure increase (group III). Additionally, there were infiltration and congestion of the urothelium together with vacuolation, suburothelial edema, and desquamation in 4 group III rabbits. Moderate or severe congestion in the lamina propria was present in bladder strips of group II rabbits. The congestion of the lamina propria was advanced, and additional moderate to severe inflammation was present in 4 rabbits of group III. Mean histopathologic scores of urothelium (P <.00001) and lamina propria (P =.002) differed significantly among groups. When the groups were compared one by one, the differences between the group I and group II and group II and III were significant (P <.05). Although serosa appeared normal in both group I and II, moderate congestion and infiltration of the serosa was present in the bladder strips of group III (P <.05). CONCLUSION: Increases in IAP for even 10 days show damaging effects on the bladder. Extended period resulted in augmentation of the damage.

Expression of beta 1 integrins in human dental pulp in vivo: a comparative immunohistochemical study on healthy and chronic marginal periodontitis samples.

AIM: The objective of this study was to determine the tissue distribution of beta 1 integrin chains in sound human dental pulps and to compare the findings with connective tissue compartments of other organs and to pulp tissue in teeth extracted due to periodontal disease. METHODOLOGY: Freshly frozen pulp tissue samples from teeth extracted for orthodontic reasons were examined and compared to samples from teeth extracted due to chronic (marginal) periodontitis. beta 1 integrin chains were determined using an indirect-immunoperoxidase technique. Seven monoclonal antibodies recognizing alpha 1, alpha 2, alpha 3, alpha 4, alpha 5, alpha 6 and beta 1 chains of Very Late Activation Antigen (VLA) integrins were used for this purpose. RESULTS: VLA-1, VLA-2, VLA-3 and VLA-5 were expressed by vascular endothelium and vascular smooth muscle in varying intensities in both groups. VLA-6 reactivity was observed in the basal surfaces of arterial, venous and capillary endothelia. Our results indicate that there was no significant difference in the expression of VLA integrins in sound pulp tissue when compared to the samples from chronic (marginal) periodontitis and the connective tissue compartments of other viscera. CONCLUSION: The present findings suggest that human dental pulp tissue is not different from other connective tissue compartments in the body with respect to VLA integrin expression, and chronic marginal periodontitis does not affect pulp tissue to a histopathologically detectable extent.

Ultrastructural deficiency in autonomic innervation in cremasteric muscle of boys with undescended testis.

BACKGROUND/PURPOSE: The cremaster muscles (CM) associated with undescended testis reveal neurogenic alterations that mainly affect type 2 fibers. The ultrastructure of CM has been evaluated to define if further evidence to explain the alterations could be identified. METHODS: CM of 8 boys with inguinal hernia and 8 boys with undescended testis at similar ages were biopsied. Samples were processed for electron microscopic evaluations. Semithin and thin sections were examined under an electron microscope. RESULTS: The CM associated with inguinal hernia showed normal ultrastructure. However, some alterations were encountered in CM associated with undescended testis. Unmyelinated fibers were diminished in number, and myelinated fibers were outnumbering the unmyelinated fibers. Marked disorientation of myofibers, redundant sarcolemma, empty sleeves of basal lamina, disarray of myofibrils, densely packed myofilaments, Z disk streaming, dilated sarcoplasmic reticulum, and dense-irregularly shaped mitochondria were repeatedly encountered. Satellite cells appeared inactive. Most of the fibers were contracted. CONCLUSIONS: The decrease in number of unmyelinated fibers appears to represent a decrease in autonomic nerve fibers. The alterations within muscle fibers may reflect a deficiency in autonomic innervation. Autonomic nervous system is highly responsive to circulating androgens. Factors decreasing the vulnerability of autonomic nervous system against androgenic effects may result in a CM with neurogenic alterations, thus inhibiting testicular descent. J Pediatr Surg 36:573-578.

Myofibroblasts defined by electron microscopy suggest the dedifferentiation of smooth muscle within the sac walls associated with congenital inguinal hernia.

OBJECTIVE: To ascertain the presence of myofibroblasts in sacs associated with inguinal hernia in children, through an ultrastructural evaluation using electron microscopy. MATERIALS AND METHODS: Sacs were obtained from 10 boys and 10 girls (of similar age, approximately 45 months) with inguinal hernia and processed for electron microscopy. Thin sections were examined specifically for the presence of myofibroblasts. RESULTS: The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the gender of origin. CONCLUSION: The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth muscle and thus such cells within the sac walls seem to originate from the smooth muscle, reflecting the dedifferentiation of smooth muscle. This dedifferentiated state may represent attempted apoptosis, which usually causes the disappearance of the smooth muscle and obliteration of the processus vaginalis after the descent of the testis into the scrotum.

Endothelial cell and stromal antigens in human periapical granulation tissue.

Periapical granulation tissue consists of vasculature of varying sizes and types, infiltrating cells, and other stromal elements. We examined the differential expression of endothelial and stroma antigens in this tissue to determine their tissue distribution in order to obtain hints on their functions. Some of the antigens examined were present only in the endothelial lining of vasculature, including high endothelial venules (e.g. CD31 and CD105), whereas others were more widely expressed by both vascular and stromal elements (e.g. CD29, CD63, CD44, and CD151). Immunohistochemical analysis using monoclonal antibodies specific to certain tissue compartments revealed the tissue architecture more precisely and the expression of certain antigens in the tissue suggested special roles for these antigens. Tissue distribution of CD63, CD143, CD147, and CD151 in periapical granulation tissue is first reported in the present study.

CD45/isotypes expression in the immune cells of human periapical lesions.

Expression of some leukocyte antigens (including CD45) and its isoforms (CD2, CD4, CD5, CD6, CD7, and CD8) was examined in the human periapical granulation tissue samples in the present study. The majority of the infiltrating cells expressed heavy molecular-weight isoforms of the CD45 antigen. Expression of CD2, CD5, CD6, and CD7 antigens was also detected, implying significant roles for these antigens in the immune reaction taking place in periapical lesions. This suggests that the immune response taking place at the periapical region is predominantly cellular and the humoral responses to antigenic challenge are conducted mainly by regional lymph nodes.

Short term human primary pulpal response after direct pulp capping with fourth-generation dentin adhesives.

The purpose of this study was to evaluate the effects of the total-etch and direct pulp capping techniques on the short-term response of mechanically exposed human primary tooth pulps using three commercially available adhesive resin systems. Class V cavities were prepared on the buccal surface of intact mandibular primary molars and exposed with a carbide bur on the cavity floor. The entire cavity except the exposure site received 36% phosphoric acid gel conditioning. Exposed pulps were capped with one of the three adhesive resins, followed by restoration of the cavities with the respective restorative materials. The teeth were extracted after 60 days and prepared according to normal histological techniques. Serial sections were stained with H/B for histological evaluations. The histopathological evaluation showed that a few of the samples in the Scotchbond Multi Purpose (SMP) and Prime & Bond 2.1 (PB) groups exhibited "attempted bridge formation", while no bridge formation was evident in the other samples. Syntac Single Component (Syntac) exhibited the most severe histological response, while the mildest reactions were observed in the SMIP group. Based on the conditions of the present study, direct pulp capping with dentin bonding agents following the total-etch technique in primary teeth can not be recommended.

Vasculogenesis in early human placental villi: an ultrastructural study.

In this study we examined the chorionic villi of 5 normal human placentas at 12-14 weeks of gestation ultrastructurally with regard to differentiation of the vascular components. The aim of the present report is to discuss the factors influencing vasculogenesis (in situ formation of blood vessels) at the ultrastructural level. Our observations have led us to think that the cytotrophoblast influences vasculogenesis in human chorionic villi. Mesenchymal-preendothelial cell groups were always found in very close association with the cytotrophoblast at the periphery of the villi, forming blood vessels. The cytotrophoblast probably attracts mesenchymal cells towards the margin of the villi by secreting vascular endothelial growth factor (VEGF). Once cells attach to the trophoblastic basement membrane they begin to differentiate into endothelial cells. This close structural relation between two cell types (cytotrophoblast and mesenchymal cells) may not be the only mechanism controlling vasculogenesis, but it seems to be one of the factors influencing the differentiation of mesenchymal cells into the endothelial cells of blood vessels in early human chorionic villi.

Cysts in human thymus: maturational forms of Hassal's corpuscles?

Presence of extracellular cystic cavities in the thymus of many vertebrates has long been known. Various forms of such structures in human thymus were observed and examined thoroughly on immunostained and serial semithin sections. We grouped these structures into five categories according to their most characteristic features. The lympho-epithelial content of the cysts clearly reflected the structural features and antigenic profile of thymic cortical parenchyma in both elongated and ovo-spherical cysts. Our findings suggest that the various types of cystic structures observed in human thymus may represent maturational stages of classical Hassal's corpuscles. Presence of cortical lympho-epithelial content and its gradual replacement with debris material also suggests a unique mechanism of thymocyte disposal.

Inguinal hernia revisited through comparative evaluation of peritoneum, processus vaginalis, and sacs obtained from children with hernia, hydrocele, and undescended testis.

BACKGROUND/PURPOSE: Histological structures of peritoneum, processus vaginalis, and sacs obtained from girls with inguinal hernia and boys with inguinal hernia, hydrocele, and undescended testis have been compared through immunohistochemical features to evaluate if any clue descriptive for the etiology of inguinal hernia exists. METHODS: Parietal peritoneums (n = 6), processus vaginalises (n = 4), female hernia sacs (n = 5), male hernia sacs (n 12), and sacs from hydrocele (n = 5) and undescended testis (n = 9) were stained with indirect immunoperoxidase method. Anti-CD9, CD26, CD29, CD31, CD36, CD44, CD49a, CD49b, CD49c, CD49d, CD49e, CD49f, CD54, CD55, CD56, CD62E & P, CD71, CD98, CD102, CD106, CD146, CD151 monoclonals and NFL-NPH, S-100 antiserums were used. The histological structures of each group of samples were identified and compared. RESULTS: Smooth muscle layers have been encountered within the walls of hernia sacs of both boys and girls. Although the hydrocele sacs have shown smooth muscle bundles distributed as patchy areas, smooth muscle bundles have been observed infrequently among sacs from patients with undescended testis. Peritoneum and processus vaginalis samples have been free of smooth muscle. CONCLUSIONS: Inguinal hernia during childhood seems to be related to the presence of smooth muscle within the wall of the sac. The smooth muscle bundles may have played a role both in prevention of obliteration and clinical outcome. Because the sacs associated with undescended testis are without smooth muscles, and herniation is not a frequent association, they may not share the same etiologic basis with inguinal hernia.

Endothelial cell adhesion molecules in human dental pulp: a comparative immunohistochemical study on chronic periodontitis.

Migration of leukocytes to inflammation sites through vascular endothelium is controlled by the interactions of adhesion molecules expressed on both endothelial cells and leukocytes, most of which are already covered by cluster of differentiation (CD) codes. We examined the expression of a variety of endothelial cell adhesion molecules in human dental pulp vasculature to obtain further evidence on the tissue distribution and function of these molecules by using an indirect immunoperoxidase technique. We obtained the pulp tissue samples from teeth extracted due to orthodontic reasons as controls and compared with those extracted due to chronic periodontitis. In all samples, both CD31 and CD146 were expressed by arterial, venous, and capillary endothelia. There was no significant difference between the staining intensity of normal and inflamed pulp tissues. CD102 expression on the endothelium was significantly stronger in chronic periodontitis pulp samples. CD106, CD62-E, CD62-P, CD105, and CD54 were variably expressed in control and chronic periodontitis groups. Our results indicate that CD102 represents the major endothelial cell adhesion molecule probably involved in the inflammatory reactions in chronic periodontitis.

Endoglin (CD 105) expression in human lymphoid organs and placenta.

Endoglin (CD 105) is a cell surface antigen widely expressed on vascular endothelium, syncytiotrophoblast, some tissue macrophages, certain culture cells (including early leukemic B-lineage) and some endothelial cell lines. Though its relation to the transforming growth factor-beta (TGF-beta) receptor system is well documented, its function and detailed pattern of expression still remain to be clarified. We examined the differential tissue distribution of endoglin in human lymphoid organs and placenta with several anti-CD 105 monoclonal antibodies (mAbs) using an indirect immunoperoxidase technique, and performed semi-quantitative measurements using an image-analyzing system for comparison. Arterial, venous and capillary endothelia in these organs were reactive with anti-CD 105 mAbs at varying intensities. Interestingly, a distinctly stronger staining pattern was observed in the high endothelial venules (HEVs) which may indicate a special role for endoglin in lymphocyte trafficking. Syncytiotrophoblast expressed endoglin strongly on their apical cell membrane. Extravillous trophoblasts at certain locations selectively expressed endoglin on their cell membranes, suggesting a special role for this surface antigen during trophoblast differentiation.

Investigation of the ultrastructurel of different cells in lymph nodules by using zinc iodide osmium tetroxide technique.

The zinc iodide -osmium tetroxide (ZIO) fixation/staining method was applied for neurocytological study and also to examine several other tissue samples including human blood and bone marrow on nerve endings in the median eminence, epidermal langerhans cells of lymphoid tissue. Although precise specificity can not be attributed to the staining reaction. Interesting staining patterns for different cell types in lymph node were observed by one of the ZIO staining solutions. The significance of ZIO positivity is briefly discussed.