Tangential Sections Research Articles

Crescent Versus Rectangle

The hallmark of Mohs micrographic surgery is using tangential tissue sections that theoretically allow 100% of the tissue margin to be examined, but when taking additional layers for second and subsequent Mohs stages, no detailed methods have been described to ensure that 100% of the tissue margins are analyzed. A rectangular or a crescent-shaped layer is often used to take second and subsequent stages. Here we compare the two techniques for their theoretic advantages and disadvantages. The advantage of the rectangular shape has been ease of processing, as well as built in vertical "nicks" that automatically mark the border of the tissue removed, but the rectangular layer may not provide 100% evaluation of the tumor margin because the vertical edges of the rectangular layer are not always completely analyzed, and thus tumor cells cannot be visualized in the vertical margins of these layers. This might result in a false-negative margin reading, which can be avoided by using the crescent layer. We propose taking second and subsequent Mohs layers with only a crescent shape, which allows true 100% tissue margin assessment.

Specialized ommatidia of the polarization-sensitive dorsal rim area in the eye of monarch butterflies have non-functional reflecting tapeta

Many insects exploit sky light polarization for navigation or cruising-course control. The detection of polarized sky light is mediated by the ommatidia of a small specialized part of the compound eye: the dorsal rim area (DRA). We describe the morphology and fine structure of the DRA in monarch butterflies (Danaus plexippus). The DRA consists of approximately 100 ommatidia forming a narrow ribbon along the dorsal eye margin. Each ommatidium contains two types of photoreceptor with mutually orthogonal microvilli orientations occurring in a 2:6 ratio. Within each rhabdomere, the microvilli are well aligned. Rhabdom structure and orientation remain constant at all retinal levels, but the rhabdom profiles, as seen in tangential sections through the DRA, change their orientations in a fan-like fashion from the frontal to the caudal end of the DRA. Whereas these properties (two microvillar orientations per rhabdom, microvillar alignment along rhabdomeres, ommatidial fan array) are typical for insect DRAs in general, we also report and discuss here a novel feature. The ommatidia of monarch butterflies are equipped with reflecting tapeta, which are directly connected to the proximal ends of the rhabdoms. Although tapeta are also present in the DRA, they are separated from the rhabdoms by a space of approximately 55 μm effectively inactivating them. This reduces self-screening effects, keeping polarization sensitivity of all photoreceptors of the DRA ommatidia both high and approximately equal.Electronic supplementary materialThe online version of this article (doi:10.1007/s00441-009-0886-7) contains supplementary material, which is available to authorized users.

Remapping of the somatosensory cortex after a photothrombotic stroke: dynamics of the compensatory reorganization

Although stroke can affect cerebral structure and function, the brain has a potential for plasticity thanks to which some degree of function can be restored. The pathways of such recovery are of great interest, since the dynamics of rewiring of the injured brain may become the basis for designing appropriate strategies of rehabilitation. We investigated the spontaneous plasticity of cortical somatosensory representations following a focal unilateral stroke in the barrel cortex of rats. Ischemic lesions were produced with the photothrombotic technique in the cortical representation of vibrissae. Functional activation of the brain in response to the stimulation of vibrissae with destroyed cortical representation was monitored through the 2 months post-stroke survival period with [14C] 2-deoxyglucose (2DG) autoradiographic brain mapping (1, 7, 28, 56 days after the stroke). 2DG uptake was measured on autoradiograms of tangential sections in several regions of somatosensory cortex and in motor, auditory and prefrontal cortex. Behavioral deficit was assessed by the gap-crossing test 3, 28, 56 days after the stroke. Changes in the activation pattern of the intact hemisphere and non-vibrissal somatosensory representations of the lesioned hemisphere evolved during the observation period. Full recovery of the behavioral function was reached 2 months after the stroke and at the same time, new foci of activation were observed in the lesioned hemisphere. At that time, hyperactivation of the somatosensory areas in the intact hemisphere subsided. The new activation foci located in representations of anterior vibrissae, front paw and hind paw were specific for the vibrissae stimulation and were most probably a new functional representation of the vibrissae. We demonstrated spatial and temporal remodeling of the brain induced by cortical stroke, leading to vicariation of function.

Myenteric plexitis in enteric dysmotility: what are the implications for clinical practice?

The term enteric dysmotility (ED) has been proposed1 to describe patients with recurrent severe gastrointestinal symptoms (nausea, vomiting, abdominal pain, abdominal distension, diarrhoea or constipation) and abnormal small bowel manometry,...

Histochemical study of detailed laticifer structure and rubber biosynthesis-related protein localization in Hevea brasiliensis using spectral confocal laser scanning microscopy

In Hevea brasiliensis, laticifers produce and accumulate rubber particles. Despite observation using histochemical methods, development stage structure and structures with ceasing functions have rarely been described. Spectral confocal laser scanning microscopy with Nile red staining simplifies laticifer structure observation in tangential sections while enhancing the resolution. Laticifer and ray images were extracted from unmixed images and used to monitor changes during growth. A laticifer network structure developed from increased anastomoses between adjoining laticifers outside of the conducting phloem, but because of increased radial division and growth of rays, the network structure ruptured and disintegrated. We also investigated immunohistochemical localization of two rubber particle-associated proteins in the laticifers: small rubber particle protein (SRPP) and rubber elongation factor (REF). Mature bark test results show that SRPP is localized only in the laticifer layers in the conducting phloem; REF is localized in all laticifer layers. Because SRPP plays a positive role in rubber biosynthesis, results show that the rubber biosynthesis capability of laticifers is concentrated where rays and the sieve tube actively transport metabolites.

Dynamic integration of subplate neurons into the cortical barrel field circuitry during postnatal development in the Golli‐tau‐eGFP (GTE) mouse

In the Golli-tau-eGFP (GTE) transgenic mouse the reporter gene expression is largely confined to the layer of subplate neurons (SPn), providing an opportunity to study their intracortical and extracortical projections. In this study, we examined the thalamic afferents and layer IV neuron patterning in relation to the SPn neurites in the developing barrel cortex in GTE mouse at ages embryonic day 17 (E17) to postnatal day 14 (P14). Serotonin transporter immunohistochemistry or cytochrome oxydase histochemistry was used to reveal thalamic afferent patterning. Bizbenzimide staining identified the developing cytoarchitecture in coronal and tangential sections of GTE brains. Enhanced green fluorescent protein (GFP)-labelled neurites and thalamic afferents were both initially diffusely present in layer IV but by P4-P6 both assumed the characteristic periphery-related pattern and became restricted to the barrel hollows. This pattern gradually changed and by P10 the GFP-labelled neurites largely accumulated at the layer IV-V boundary within the barrel septa whereas thalamic afferents remained in the hollows. To investigate whether this reorganisation is dependent on sensory input, the whiskers of row 'a' or 'c' were removed at P0 or P5 and the organisation of GFP-labelled neurites in the barrel cortex was examined at P6 or P10. In the contralateral region corresponding to row 'a' or 'c' the lack of hollow to septa rearrangement of the GFP-labelled neurites was observed after P0 row removal at P10 but not at P6. Our findings suggest a dynamic, sensory periphery-dependent integration of SPn neurites into the primary somatosensory cortex during the period of barrel formation.

The effects of thermal treatment on the mechanical properties of wild Pear ( Pyrus elaeagnifolia Pall.) wood and changes in physical properties

The aim of the study was to investigate the effects of thermal treatment on the mechanical and physical properties of wild pear wood. The results obtained for thermal treatment at 160 °C for 2 h showed that the modulus of elasticity was increased about 5%, while bending strength and compression strength decreased by 7.42% and 7.55%, respectively. The physical properties of wild pear wood were improved as 2.6%, 5.3%, 8.5% and 0.8% swelling in tangential, radial and longitudinal sections and 1.7%, 1.1% and 0.9% at 50, 65 and 85 Rh% and changes in Δ Eab ∗ was 8.50%, respectively. It was determined that the changes ratio of these properties increased as the temperature and durations were increasing. Therefore, wild pear wood can be used as an alternative for tropical woods in decoration and veneer industry.

Diffraction in lips and beak-to-beak caustics

When an initially smooth wavefront is allowed to propagate, the first caustic to appear on a transverse screen is typically a lips. Lips and beak-to-beak caustics are tangential sections through three-dimensional cusp caustics that have curved ribs. They have universal shapes and this paper analyses the diffraction patterns that would be seen on a screen accompanying the caustics. These form two universal one-parameter sets, depending on how much of the cusp diffraction (Pearcey) pattern is intercepted, unlike the canonical catastrophes, which all have universal forms. An experimental diffraction pattern obtained by passing light through a water drop is compared with a computed beak-to-beak pattern.

ER stress protects from retinal degeneration

The unfolded protein response (UPR) is a specific cellular process that allows the cell to cope with the overload of unfolded/misfolded proteins in the endoplasmic reticulum (ER). ER stress is commonly associated with degenerative pathologies, but its role in disease progression is still a matter for debate. Here, we found that mutations in the ER-resident chaperone, neither inactivation nor afterpotential A (NinaA), lead to mild ER stress, protecting photoreceptor neurons from various death stimuli in adult Drosophila. In addition, Drosophila S2 cultured cells, when pre-exposed to mild ER stress, are protected from H(2)O(2), cycloheximide- or ultraviolet-induced cell death. We show that a specific ER-mediated signal promotes antioxidant defences and inhibits caspase-dependent cell death. We propose that an immediate consequence of the UPR not only limits the accumulation of misfolded proteins but also protects tissues from harmful exogenous stresses.

Perineural Invasion

Mohs surgeons have expanded the range of cancers treated using the Mohs technique. Mohs surgeons today are expected to diagnose perineural invasion (PNI) when as little as one nerve is involved. To address the issue of identification and significance of perineural invasion from the perspective of the Mohs surgeon. The experience of other medical specialties dealing with the same issue are reviewed and applied. This article is based on a review of the entire medical literature regarding PNI. PNI is a significant complication of cancers, regardless of the organ of origin. The most common complication of PNI is recurrence of the cancer. Leptomeningeal carcinomatosis occurs in neglected or aggressive cancers. The process is indolent and contiguous, lending itself well to treatment with Mohs surgery. There are diagnostic mimics of PNI. Variation of reported incidences and cure rates suggest that diagnostic criteria for PNI may not be consistent from study to study. We propose the following definition for the minimum histopathologic criteria required to make a diagnosis of PNI: "In the presence of a malignancy, PNI may be diagnosed according to the observation of cytologically malignant cells in the perineural space of nerves. In equivocal cases, the observation of total or near-total circumferential involvement is supportive, as is the presence of perineural tracking in tangential sections and intraneural involvement."

Effect of compressive load on the dimensional changes of the Japanese larch dried in a radio-frequency/vacuum drier

This study investigated the effect of a compressive load of 0.092 MPa on the dimensional changes of Japanese larch in a humidity chamber after continuous radio-frequency/vacuum drying. The dimensional changes in the loading directions were significantly increased while those perpendicular to the loading directions were decreased. The shrinkages showed higher values in continuous drying than in intermittent drying. For the specimens loaded on their tangential sections, the radial shrinkages were even higher than the tangential shrinkages; thus, the tangential/radial shrinkage ratio was decreased by 0.27. The transverse hygroscopicity was reduced for the specimens loaded on their cross sections, but increased for the specimens loaded on their tangential sections.

Axon bundle spacing in the anterior cingulate cortex of the human brain

The anterior cingulate cortex (ACC) is implicated in neuropsychiatric disorders. Post-mortem axon bundle data will be important to complement novel MRI methods for analysing cortical diffusion data. [Jespersen SN, Kroenke CD, Ostergaard L, et al. Modeling dendrite density from magnetic resonance diffusion measurements. Neuroimage. 2007; 34:1473–86] Therefore we aimed to assess perimeter, area, density and spacing of axon bundles in BA24 not previously measured in the human ACC using image analysis of 10 μm-thick tangential sections of layer IV in 4 normal patients. Axon bundle mean perimeter was 53.8 μm, mean area was 197.1 μm 2, mean density was 226.3/mm 2, and mean spacing was 73.8 μm. Thus, axon bundles were widely spaced relative to cell body minicolumns and other prelimbic areas. A review of the literature suggests that there is hierarchical regional variation of bundle and column spacing.

Fruit anatomy of species of Solanum sect. Acanthophora (Solanaceae)

The fruits of 10 species of Solanum sect. Acanthophora were studied. Cross and/or longitudinal and/or tangential microtome sections, stained mostly with astra blue/basic fuchsin, were made for microscopic examination. Three different kinds of cells were found in the epidermis, immediately below which a hypodermis, consisting in any of four types of structures, was always found. The mesocarp exhibits two histologically differentiated zones, an external one (formed by normal or spongy parenchyma, according to the species), and an internal one, commonly juicy, and with proliferations among the seeds. The diagnostic value of all these structures is assessed. Morpho-anatomical information is used to define fruit types beyond the berry, traditionally described for Solanum, and the probable dispersal syndrome related to them is discussed. Fruit similarities are slightly noticeable in several cases, while differences may be the result of their sexual system – which affects specially the size – and their histology, which is related to the dispersal syndrome. The comparison of our data with previous molecular phylogeny of the section suggests that a significant morphological variation is not associated with significant DNA sequence changes.

Spatiotemporal distribution of proteoglycans in the developing rat's barrel field and the effects of early deafferentation

The isolectin Vicia villosa B(4) (VV) selectively recognizes N-acetyl-galactosamine-terminal glycoconjugates that form perineuronal nets (PNNs) around a subset of neurons in the cerebral cortex. PNNs are thought to participate in the guidance of incoming thalamic axons and in the posterior stabilization and maintenance of synaptic contacts. Here we examine the spatial and temporal distribution of biotinylated VV in tangential sections through layer IV of the posteromedial barrel subfield in the primary somatosensory cortex (PMBSF) of rats ranging from postnatal day (P)3 to P60, which underwent unilateral deafferentation of whiskers at birth. In the afferented hemisphere, labeling first appears at P5, with a diffuse distribution, probably associated with neuropil, inside PMBSF barrels. VV distribution remains diffuse during the following week, and declines around P17. From P24 onward, however, proteoglycans form PNNs around cell bodies preferentially localized in septal regions of the PMBSF. In the contralateral, deafferented PMBSF the diffuse labeling also appears on P5, but first develops into elongated, homogeneous stripes, which disappear after P24, leaving only scattered cell bodies along layer IV. Our results indicate that proteoglycans appear simultaneous to barrel formation in the developing rat while segregation of PNNs to septal cells might be driven by afferent activity.

Developmental and comparative aspects of posterior medial thalamocortical innervation of the barrel cortex in mice and rats

AbstractConfocal laser scanning microscope image of a tangential section through layer IV of barrel cortex taken from a rat pup aged postnatal day 6. Thalamocortical axons (TCAs) from the VPM nucleus are labeled by DiD (blue); their terminations form whisker‐related clusters that occupy the barrels. TCAs from the POm nucleus are labeled by DiI (red). By this age, their terminations mostly occupy the intervening septa that separate the barrels, although a few axons are found within the barrels. Thus, by the end of the first postnatal week, an adult‐like pattern of interdigitated thalamocortical projections is largely established. J. Comp. Neurol. 509:239‐258, 2008. © 2008 Wiley‐Liss, Inc.

Developmental and comparative aspects of posterior medial thalamocortical innervation of the barrel cortex in mice and rats

AbstractConfocal laser scanning microscope image of a tangential section through layer IV of barrel cortex taken from a rat pup aged postnatal day 6. Thalamocortical axons (TCAs) from the VPM nucleus are labeled by DiD (blue); their terminations form whisker‐related clusters that occupy the barrels. TCAs from the POm nucleus are labeled by DiI (red). By this age, their terminations mostly occupy the intervening septa that separate the barrels, although a few axons are found within the barrels. Thus, by the end of the first postnatal week, an adult‐like pattern of interdigitated thalamocortical projections is largely established. J. Comp. Neurol. 509:239‐258, 2008. © 2008 Wiley‐Liss, Inc.

Interaction and Colocalization of CaBP4 and Unc119 (MRG4) in Photoreceptors

To characterize the interaction of the neuron-specific protein CaBP4 with the synaptic photoreceptor protein Unc119 homolog (MRG4). The interaction of CaBP4 and Unc119 was studied using affinity chromatography, yeast two-hybrid system, coimmunoprecipitation, and gel overlay assay. The colocalization of CaBP4 and Unc119 was analyzed using immunohistochemistry. Unc119, CaBP4, and synaptic proteins were examined in photoreceptors using immunohistochemistry and in synaptic tangential sections of flatmounted frozen retinas using Western blot analysis. Biochemical evidence supported the interaction of CaBP4 with Unc119. CaBP4 and Unc119 colocalized in the photoreceptor synapse of adult retina and during postnatal retinal development. A reduction in Unc119 levels was observed in the photoreceptor terminals of CaBP4-knockout mice compared with wild-type mice and was higher than the reduction of other synaptic proteins. This study provides evidence for the interaction of CaBP4 with Unc119 at the photoreceptor synapse. This interaction suggests a functional relationship between CaBP4 and Unc119, further supporting a role for these proteins in neurotransmitter release and in the maintenance of the photoreceptor synapse.

Three-dimensional Observation of the Enamel Prisms of Subhyracodon Molars

Enamel prisms are a morphological feature and Hunter-Schreger bands are the main microstructure of mammalian tooth enamel. Subhyracodon is an extinct rhinocerotoid that inhabited North America in the Oligocene geologic period. The Hunter-Schreger bands of some rhinocerotoids run vertically along the axis of the tooth, and the boundary between bands is distinct in the tangential section. In our observation of Subhyracodon tooth enamel, vertical prism decussation along the tooth axis could be observed clearly in the inner three-fourths of the enamel. In this study, the path of the prisms was digitized and reconstructed three-dimensionally. The course of each prism undulated strongly at the border of the bands, and the prisms did not maintain their relative relations but showed positional changes and displacement of adjacent Hunter-Schreger bands.

Variability in Apical Elongation of Wood Fibres in Lonchocarpus Sericeus

Morphological variability in wood fibres of Lonchocarpus sericeus (Poir.) Kunth ex DC. (Leguminosae), a tropical hardwood tree with doublestoreyed cambium, was examined in thin tangential and transverse sections as well as in macerations of wood tissue. Occurrence of characteristic protrusions (lateral expansions) was detected on the extended part of the main fibre body. Distance between the adjacent protrusions corresponded to the height of a storey (horizontal tier) of the cambial initials. Rays were shorter in height than the neighbouring fusiform initials and therefore unable to reach the boundary of the storey. This situation facilitated the lateral expansion of the adjoining fibres during their apical elongation by intrusive growth. The presence of the characteristic protrusions on the fibre body thus indicated that the given fibre was associated with a double-storeyed cambium having rays shorter than the length of fusiform initials. The ultimate shape of fibres was thus correlated to the height of storeys and the height and width of rays.

Anatomical Features Of Radial Resin Canals In Pinus Densiflora

We investigated radial resin canals in Pinus densiflora by means of serial tangential sections taken from phloem to xylem through the cambium. The canals were found within fusiform rays in both phloem and xylem. The ducts were closed in the cambial zone, but opened at widely differing distances from the cambium among individual radial resin canals, ranging from 120 to 340 μm on the phloem side and from 260 to 640 μm on the xylem side. Further, the ducts were not open continuously on both sides. The average number of radial resin canals in the tangential plane was 0.76/mm2. In the cambial zone, central cells of fusiform rays which might develop into epithelial cells later, were smaller and more deeply stained than the surrounding ray initial cells, allowing them to be identified at the initial stage. Two or more radial resin canals situated nearby each other were connected through an axial resin canal.