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PubMed2006

[Expression of osteopontin in the pericystic layer of hepatic hydatid cyst].

OBJECTIVE: To investigate the expression and distribution of osteopontin (OPN) in the pericystic layer of Echinococcus granulosus cyst. METHODS: 60 surgically excised cysts were studied with HE and immunohistochemistry staining by using antibodies specific for OPN. Immunofluorescence double labeling technique and Media Cybernetics Image (Pro Plus 5.1 software) were used to appraise the relationship between the OPN and macrophages (CD68). RESULTS: Expression of OPN was found at various degree in hydatid cysts, 75% (45/60) was distributed in the intra-layer at the parasite side, 8.3% (5/60) distributed in the extra-layer near the side of liver parenchyma ("exocyst"-layer vs "adventitia"-layer, P<0.01). Macrophages were identified between the intra-layer and extra-layer, and OPN was observed in most of the macrophages. Meanwhile, OPN was concurrently found with the deposit of calcium in a similar distribution in the hydatid cyst. CONCLUSION: Osteopontin mainly distributes in the intra-pericystic layer of hepatic hydatid cyst.

Adolescent↗
PubMed1990

Determination of the extracellular tortuosity in nuclear layers of the central nervous system by resistance measurements on a geometrical model.

The electrical resistivity of nuclear layers within CNS tissues is simulated by a densely packed array of glass spherules with a thin silver layer on their surfaces. Various mean spherule diameters and different thicknesses of the silver layer are tested; the relations between spherule diameter and thickness of silver mantle are in the same range as those between cell soma diameters and width of the extracellular clefts. Measuring the contribution of the silver layers to the total volume--corresponding to the extracellular volume fraction alpha within CNS tissues--and the resistance of columns of silvered spherules, tortuosity factors lambda 2 are calculated. Means of lambda 2 are found to vary within 5.6 and 9.2, independent of both spherule diameters and thickness of the silver layer, but strongly dependent on the packing density of the spherules. This latter dependence is described by a simple formula. These results are used to calculate the resistivities of the nuclear layers of the retina and of the granular layer in the hippocampal area dentata, based on morphometric data gained from own studies and literature reports, respectively. It is shown that such layers with densely packed cells express very high resistivity because of both low extracellular volume fraction and high tortuosity. Implications for current source density analyses, and for pathological events like epileptogenesis, are discussed. In an appendix, an analytical solution of the problem is given for the case of a cubic array of surface-conducting spheres.

Animals↗
PubMed1984

Physiological organization of layer 4 in macaque striate cortex.

Numerous highly angled electrode penetrations through the opercular region of macaque striate cortex reveal that layers 4A, 4C alpha, and 4C beta--the primary input sublaminae for axons from the lateral geniculate nucleus (LGN)--are retinotopically organized on a fine scale and populated mostly by monocularly driven cells having small receptive fields and lacking orientation selectivity. Layer 4B, which does not receive a direct thalamic input, contains orientationally selective cells, and many of these are also direction selective. To a significant degree the response properties of cells in layers 4C alpha and 4C beta reflect the response properties of their respective afferent inputs, from the magno- and parvocellular laminae of the LGN. Accordingly, cells in layer 4C alpha have lower contrast thresholds and larger minimum response fields than do the cells in layer 4C beta. In contrast to this clear-cut separation, the cells of layer 4A (whose major source of direct LGN input arises from the parvocellular layers) exhibit both high and low contrast thresholds. With regard to the precision of retinotopic mapping that is seen in lamina 4C, it is noteworthy that there is substantial overlap among the minimum response fields of neighboring neurons. Due to a larger mean receptive field size, this overlap is greater in layer 4C alpha than it is in 4C beta. In either sublamina, however, the minimum cortical distance that separates different and nonoverlapping parts of the visual field corresponds closely--within a factor of 2--to the known arborizational spreads of single geniculate afferents.

Animals↗
PubMed1983

Enzymatic treatment of long-term human marrow cultures reveals the preferential location of primitive hemopoietic progenitors in the adherent layer.

Recent studies with long-term mouse marrow cultures have indicated the importance of the adherent layer as a primary reservoir of the most primitive stem cells, from which derivative stem cells and more differentiated progenitors are continuously generated. We have now examined the role of the adherent cell layer in long-term human marrow cultures from this point of view. Prerequisite to such an undertaking was the development of a nontoxic and reproducible method for detaching the adherent layer and making it into a single-cell suspension suitable for characterization by colony assays. Both trypsin and collagenase could be used to obtain suspensions that met these criteria. Lack of toxicity was demonstrated by the preservation of CFU-E, BFU-E, and CFU-C plating efficiency in fresh human marrow cell suspensions exposed to the same enzymatic treatments. Collagenase treatment of long-term marrow culture adherent layers was considered superior because it freed all hemopoietic colony-forming cells but left some of the other cells still adherent. Using this method, we found that CFU-C, BFU-E, and CFU-G/E were consistently detectable in the adherent layer for at least 8 wk, with the majority of the BFU-E and CFU-G/E being located in the adherent layer (70%-75% after 2-3 wk and more than 90% by 7-8 wk). Although corresponding numerical differences in adherent and nonadherent CFU-C populations were not observed, the colonies derived from them showed marked differences in the size they achieved; the adherent layer being the exclusive site of CFU-C, with a very high proliferative capacity. These findings emphasize the importance of assessing the progenitor content of the adherent layer of long-term human marrow cultures and provide an appropriate methodology.

Anemia↗
PubMed1983

A study of the properties, morphogenetic potencies and prospective fate of outer and inner layers of ectodermal and chordamesodermal regions during gastrulation, in various Anuran amphibians.

In both the ectodermal and the chordamesodermal regions of Anuran embryos, the outer layer of cells possesses epithelial properties and has the same restricted morphogenetic potencies. It is thus interchangeable between the regions, capable of epiboly and, when underlain by notochord material, of the formation of bottle-shaped cells as at the blastoporal groove, and invagination. When taken from the chordamesoderm region, this outer layer has no inducing effect on the ectoderm of the early gastrula. In normal development the outer layer of the neural plate takes an active part in forming the neural tube cavity. It gives rise to the neuroepithelial roof of the diencephalon and medulla oblongata and, when underlain by neuroblasts that develop from the inner cell layers, to ependymal cells of the brain wall. The outer layer of the notochord material is included in the epithelial layer underlying the roof of the gastrocoel - the hypochordal plate. The inner layers of these regions consist of loosely arranged cells and normally have no epithelial properties although, when taken from the ectoderm region, they may acquire such properties upon long-term contact with the environment. However they have wide morphogenetic potencies; the differences in these potencies between cells taken from the various presumptive regions being less than the differences between outer and inner cell layers in each region. Maps are provided which show the arrangement of presumptive rudiments in the ectoderm and chordamesoderm on sagittal sections through Bombina bombina embryos in early and late gastrulation.

Animals↗
PubMed1994

Otx1 and Otx2 define layers and regions in developing cerebral cortex and cerebellum.

Within the cerebral and cerebellar cortices, neurons are organized in layers that segregate neurons with distinctive morphologies and axonal connections, and areas or regions that correspond to distinct functional domains. To explore the molecular underpinnings of pattern formation in layered regions of the CNS, we have characterized the patterns of expression of two homeodomain genes, Otx1 and Otx2, by in situ hybridization during embryonic and postnatal development in the rat. Otx1 and Otx2 are vertebrate homologs of the Drosophila gap gene orthodenticle, and are expressed during the development of the murine CNS (Simeone et al., 1992). Here we report that Otx1 mRNA is expressed in a subpopulation of neurons within cortical layers 5 and 6 during postnatal and adult life. This gene is also expressed by the precursors of deep-layer neurons within the developing cerebral ventricular zone, but is apparently downregulated by the progenitors of upper-layer neurons; Otx1 is never expressed by the neurons of layers 1-4. The spatial and temporal patterns suggest that Otx1 may play a role in the specification or differentiation of neurons in the deep layers of the cerebral cortex. Within the cerebellum, mRNAs for Otx1 and Otx2 are found within the external granular layer (EGL), but in three spatially distinct domains. During postnatal development, Otx1 is expressed within anterior cerebellar lobules; Otx2 mRNA is localized posteriorly, and a region of overlap in mid-cerebellum defines a third domain in which both genes are expressed. The boundaries of Otx1 and Otx2 expression correspond to the major functional boundaries of the cerebellum, and define the vestibulocerebellum, spinocerebellum, and pontocerebellum, respectively. Spatially restricted patterns of hybridization are observed early in postnatal life, at times that correspond roughly to the invasion of spinal and pontine afferents into the cerebellum (Arsénio-Nunes and Sotelo, 1985; Mason, 1987). These results raise the possibility that Otx1 and Otx2 play a role in cerebellar regionalization during early development.

Amino Acid Sequence↗
PubMed1993

Continuous, nonlocking, single-layer repair of the low transverse uterine incision.

Continuous, locking, single-layer closure of the low transverse uterine incision has been used, with a reportedly decreased risk of endometritis, decreased operating time and no increased risk of rupture with subsequent vaginal birth when compared with the more traditional, two-layer repair. However, in other tissues, such as fascia and skin, locking sutures cause increased tissue damage and weaker scars. We decided to determine the safety in the perioperative period of continuous, nonlocking, single-layer repair. Over a six-month period, 100 patients who had continuous, nonlocking, single-layer repair of their low transverse uterine incisions were compared with 100 matched controls who had the traditional, two-layer repair of a locking suture followed by an imbricating layer. Febrile morbidity, rates of endometritis, blood loss, requirements for additional hemostatic sutures and operating times were compared. Except for increased additional hemostatic suture use and decreased operating times in the single-layer group, we found no differences between the two methods. The continuous, nonlocking, single-layer technique is not only expedient and cost efficient but also safe in the perioperative period. It has the additional theoretical advantage of less tissue damage, which may result in a stronger wound and thus in a reduced risk of rupture with subsequent labor.

Adolescent↗
PubMed1997

Coronal leakage: effects of smear layer, obturation technique, and sealer.

Coronal microleakage may be a major factor in the etiology of treatment failure. This study examined the effect of obturation technique, sealer, and the presence of smear layer on coronal microleakage. Two hundred extracted human teeth were assigned to 20 treatment groups. Groups were examined with the smear layer present or smear layer removed (17% REDTA). Access cavities were exposed to artificial saliva then Pelikan Ink. Teeth were cleared and linear dye penetration measured. When all groups with the smear layer removed were compared with all groups with the smear layer present, significantly less leakage was seen when the smear layer was removed. Ultrafil displayed significantly more leakage than all other groups. Vertical compaction of lateral condensation and Thermafil obturations significantly reduced leakage. AH-26 displayed significantly less leakage than Roth's 811 sealer. These results indicate that removal of the smear layer, the use of AH-26, and vertical compactin have cumulative effects in reducing coronal leakage.

Analysis of Variance↗
PubMed1999

Long-term evaluation of the influence of smear layer removal on the sealing ability of different sealers.

The purpose of this study was to examine the effect of the smear layer on apical microleakage over 16 wk. One hundred and four extracted human teeth were assigned to four groups treated as follows: group A1--smear layer was left intact and canals were obturated with gutta-percha and Roth 811; group A2--smear layer was left intact and canals were obturated with gutta-percha and AH26; group B1--smear layer was removed and canals were obturated with gutta-percha and Roth 811; and group B2--smear layer was removed and canals were obturated with gutta-percha and AH26. Microleakage was measured by the electrochemical method. In parallel, 12 teeth were examined under a scanning electron microscope. The results indicated that the smear layer removal resulted in a statistically significant reduction of microleakage values in groups obturated with AH26. The presence or absence of smear layer had no significant effect on the sealing ability of Roth 811.

Bismuth↗
PubMed1992

The effect of smear layer upon the coronal leakage of gutta-percha fillings and a glass ionomer sealer.

The effect of the removal of the smear layer on coronal leakage of root fillings was studied using two sealer cements. Sixty single-rooted teeth with mature apices were prepared chemomechanically using a modified double-flared technique with non-cutting tipped files and copious irrigation with 2% sodium hypochlorite. The teeth were randomly allocated to four groups of 15 teeth each. Two groups were treated with 40% citric acid to remove the smear layer. Two groups of teeth, one with and one without smear layer, were filled by lateral condensation of gutta-percha with either Tubliseal or a resin-based glass ionomer, Vitrebond. The teeth were stored for 1 week, thermocycled, and the extent of coronal leakage determined for each group after immersion in Indian ink for 90 h. The teeth were demineralized, dehydrated and immersed in methyl salicylate which rendered them transparent. Linear measurement of dye penetration was recorded. The mean depth (+/- SD) of leakage for the groups in which the smear layer was left intact was 4.26 +/- 1.53 mm and 6.83 +/- 1.65 mm for the Vitrebond and Tubliseal, respectively. When the smear layer had been removed, the mean depth of leakage for the Vitrebond group was 1.13 +/- 0.29 mm, and 3.72 +/- 1.23 mm for the Tubliseal group. There was a statistically significant difference in leakage between the groups (P < 0.001). With both sealers, those teeth in which the smear layer had been removed showed less leakage than the specimens in which the smear layer was left intact (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Citrates↗
PubMed1994

An apical leakage study in the presence and absence of the smear layer.

The apical seal produced by low-temperature injection of gutta-percha, with or without root canal sealer, in the presence or absence of the smear layer was evaluated quantitatively using an electrochemical technique. The root canals of 44 teeth were prepared with the smear layer intact following a final flush of NaOCl (group 1), while the root canals of a further 44 teeth were prepared and the smear layer removed with a final flush with EDTA followed by NaOCl (group 2). Subgroups were obturated using Ultrafil System alone or accompanied by Calciobiotic Root Canal Sealer. Microleakage data was expressed as a percentage of apical leakage evident in each group. Statistical analysis of the results revealed that the groups obturated with Ultrafil alone showed no significant differences in leakage compared with the groups where sealer was used, either when the smear layer had been left intact or removed. (P > 0.05). However, comparison of the combined two groups with smear layer present versus the combined two groups with smear layer removed showed a highly significant difference (P < 0.01), with the incidence of leakage reduced in the absence of the smear layer.

Chi-Square Distribution↗
PubMed2005

The influence of smear layer on coronal leakage of Roth 801 and AH26 root canal sealers.

The aim of this in vitro study was to examine the effect of removal of smear layer on the coronal seal of two commonly used root canal sealers: Roth 801, a zinc oxide-eugenol-based sealer and AH26, an epoxy resin-based sealer. Ninety-six single-rooted human teeth were used. The teeth were instrumented and assigned to four experimental groups of 20 teeth each, with 10 teeth as controls and the remaining six teeth examined under a scanning electron microscope. The teeth in the experimental groups (80 teeth) were divided into four sub-groups and were obturated by laterally condensed gutta-percha with the two sealer cements as follows: Group A1: smear layer left intact and AH26 cement used as sealer; Group A2: smear layer left intact and Roth 801 cement used as sealer; Group B1: smear layer removed and AH26 cement used as sealer; and Group B2: smear layer removed and Roth 801 cement used as sealer. Coronal microleakage was evaluated by measuring the distance of dye penetration. The data was statistically evaluated using a two-way ANOVA test. The results showed that removal of the smear layer resulted in a statistically significant reduction of microleakage values in the groups obturated with AH26 compared with the groups obturated with Roth 801 sealer. It was concluded that the removal of smear layer has a significant influence on the degree of microleakage in obturated root canals.

Adhesiveness↗
PubMed2000

[Should the dentin smear layer be preserved or eliminated? (Review of the literature)].

The smear layer is a direct consequence of instrumentation of the root canal wall. Hand instrumentation as well as ultrasonic instrumentation produce a smear layer on the canal wall. This smear layer is composed of dentine, remnants of pulp tissue and odontoblastic processes and bacteria in an infected canal. Removal of the smear layer is accomplished by the irrigation of root canals with EDTA (17%) followed by NaOCl (5.25%). Permeability of the dentine is increased by the removal of smear layer. In this way the bacteria within the infected tubuli can be more easily destroyed by an intracanal dressing. Whether the removal of smear layer decreases the apical leakage is uncertain. To establish the clinical consequences from removal or preservation of the smear layer, further research is needed.

Bacteria↗
PubMed2001

Generation of the germ layers along the animal-vegetal axis in Xenopus laevis.

After completion of gastrulation, typical vertebrate embryos consist of three cell sheets, called germ layers. The outer layer, the ectoderm, which produces the cells of the epidermis and the nervous system; the inner layer, the endoderm, producing the lining of the digestive tube and its associated organs (pancreas, liver, lungs etc.) and the middle layer, the mesoderm, which gives rise to several organs (heart, kidney, gonads), connective tissues (bone, muscles, tendons, blood vessels), and blood cells. The formation of the germ layers is one of the earliest embryonic events to subdivide multicellular embryos into a few compartments. In Xenopus laevis, the spatial domains of three germ layers are largely separated along the animal-vegetal axis even before gastrulation; ectoderm in the animal pole region; mesoderm in the equatorial region and endoderm in the vegetal pole region. In this review, we summarise the recent advances in our understanding of the formation of the germ layers in Xenopus laevis.

Animals↗
PubMed2004

Influence of natural fruit juices in removing the smear layer from root surfaces--an in vitro study.

Certain elements of a patient's diet may be associated with dentin hypersensitivity. The intent of this study was to evaluate the degree of removal of the smear layer from dentin surfaces by various fruit juices. A smear layer was created on extracted human teeth by manual scaling. The roots were reduced and distributed into 8 experimental groups. Distilled water was the negative control. The juices were applied by 2 methods: topical application and topical application with friction. Specimens were photomicrographed and graded according to an index of smear layer removal. With topical application, all but 2 of the tested substances resulted in significantly greater removal of the smear layer and opening of dentinal tubules than was the case with the negative control (p = 0.05); the exceptions were Gala apple and Italian grape juices, which were no different from the control. For the active application (with friction), most substances removed more smear layer than the control (p < 0.05); Gala apple, Italian grape and orange juices were similar to the control. For each of the tested substances, removal of the smear layer did not differ with the method of application (topical vs. friction; p > 0.05). It is concluded that natural fruit juices can remove the smear layer from dentin surfaces, and the efficacy of this removal varies with the type of juice.

Analysis of Variance↗
PubMed2004

Effect of the hydration status of the smear layer on the wettability and bond strength of a self-etching primer to dentin.

PURPOSE: To evaluate the microtensile bond strength (MTBS) of a resin-based composite to smear layer-covered dentin using a self-etching primer, Clearfil SE Bond (CSEB), under two different hydration states. Surface roughness and wettability (contact angle measurements) of water and the CSEB primer were also evaluated on this substrate. METHODS: Contact angle (CA) measurements were performed on four caries-free extracted human third molars. The specimens were sectioned parallel to the occlusal surface to expose the moderately deep dentin and ground flat (180-grit SiC) under water to provide uniform flat surfaces. In two samples, the smear layer was completely air-dried; in the other two specimens, the smear layer was briefly air-dried. Contact angle measurements were performed to assess wettability of water and CSEB primer using the Axisymmetric Drop Shape Analysis technique. Surface roughness (SR) was determined with a contact profilometer. In another four molars, CSEB was applied to the smear layer-covered dentin with both hydration states. Resin build-ups were performed incrementally with Tetric Ceram. After storage for 24 hours in water at 37 degrees C, the teeth were sectioned to obtain bonded beams with an average cross-sectional area of 1.0 mm2. Each beam was tested in tension in an Instron machine at 0.5 mm/minute. Kolmogorov-Smirnov and Student t-tests were performed at a 95% significance level. RESULTS: Observed water contact angles were lower on the hydrated smear layer but no differences were found between contact angles on completely and briefly air-dried smear layer when the primer was used for CA measurements. SR was similar for both substrates and MTBS was greater when the adhesive was applied on the completely air-dried smear layer.

Acid Etching, Dental↗
PubMed1993

[Separation and identifying features of the cardiac aglycones and glycosides of Nerium oleander L. flowers by thin-layer chromatography].

The present work was aimed at extracting some cardiotonic glycosides from Nerium oleander L. (N.o.L.) flowers, free from phytosterols and their esters and at resolving themselves by thick- and thin-layer chromatography. This work may contribute to the scientific recognition of N.o.L. drugs in the field of forensic medicine. MATERIALS AND METHODS. Apparatus. Kieselgel F254 thin-layer (250 mu) and Kieselgel thick-layer (2 mm) glass plates were used. MATERIALS. Chromatographic solvents were used; detectors were p-toluene sulphonic acid (PTSA) and antimony trichloride (SbCl3). STANDARDS. The following standards were used: gitoxigenin, oleandrin, digitoxin, and stigmasterol. Standard solutions were prepared at a M-3 concentration. The solvent system is described in Table I. EXTRACT. The extract was prepared using a mixture of solvents (hexane-diethylether-acetic acis, 50:50:1 v/v). With this mixture we noted that, in thin-layer chromatography, the used standards remained at the origin, while phytosterols and their esters migrated. White flowers of N.o.L. were air dried in the shade at room temperature, powered, and macerated in hexane-diethylether acetic acid for 24 hours. After removal of the phytosterols the remacerating powder was further percolated using a chloroform-methanol mixture (1:1.7 v/v) in order to extract the aglycone and the cardiac glycosides. As the medium's thin-layer chromatogram showed the absence of corresponding spots to test samples, the chloroform-methanol media were combined and evaporated under vacuum. The residue was redissolved in the chloroform-methanol mixture. The obtained extract concentration consisted of 5 grammes of dried flowers in 1 milliliter of solution, called extract E (Fig. 1). RESULTS. The results are reported in Figures 2 and 4 and in Table II (see text for explanation of symbols). Extract E (Fig. 2) and the F1, F2, and F3 concentrated fractions were examined by thin-layer chromatography (Fig. 1 and 3). Only the F3 fraction revealed compounds with the same chromatographic path and colours (detected by PTSA and SbCL3) as the reference standards gitoxigenin, oleandrin, and digitoxin. This finding was confirmed by using five different solvent-systems (Fig. 4). DISCUSSION AND CONCLUSION. The present study shows that the cardiac steroids and other constituents of Nerium oleander's flowers are separated in three fractions by thick-layer chromatography free from phytosterols and their esters. This result may have useful implications in the fields of analytical toxicology and forensic medicine and potential application in clinical practice given that cytotoxic and antileukemic activities of the extracts from plants containing cardiac glucosides have been reported.

Cardiac Glycosides↗
PubMed1993

Hemispheric differences in layer III pyramidal neurons of the anterior language area.

OBJECTIVE: The major objective of this study was to determine if the lateralization of motor speech functions may be associated with hemispheric differences in the size of layer III pyramidal neurons in Brodmann's area 45. DESIGN: A case series design involving postmortem human specimens was used to compare the cross-sectional area of NissI-stained layer III pyramidal neurons of Brodmann's area 45 from the left and right hemispheres. SUBJECTS: A convenience sample consisting of seven cases with no known neurological or psychiatric disorders was obtained at autopsy. MAIN OUTCOME MEASURES: The cross-sectional area of layer III pyramidal neurons in both left and right hemispheres was measured in four fields per hemisphere per brain using a computerized image analysis system. Measurements of both the largest layer III pyramids and of all layer III pyramids were done. RESULTS: The largest layer III pyramidal neurons of area 45 were significantly larger in the left than in the right hemisphere in both an unblinded and a blinded series of measurements. However, this hemispheric difference appeared to be restricted to the largest neurons, since the mean size of all layer III pyramids in this area was not significantly different in the left and right hemispheres. CONCLUSIONS: The presence of a unique population of large pyramidal neurons in left Brodmann's area 45 may be related to the involvement of this region in the circuitry that mediates motor speech functions.

Adult↗