Histological Layers Research Articles

Endoscopic ultrasonography: current clinical role

Endoscopic ultrasonography appeared in the clinical arena almost 20 years ago and it has now become a well integrated technique in everyday hospital practice. More than 2000 scientific papers published in the literature have demonstrated its high accuracy for the diagnosis and staging of a variety of benign and malignant conditions. The instrumentation consists of a special endoscope, modified by a high-frequency ultrasound transducer placed on its tip, and an ultrasound driving unit. The main indications to endoscopic ultrasonography can be explained by its ability to visualize the gut wall as a multi-layer structure corresponding to histological layers. Other important indications derive from its capability of displaying, very closely, the structures and lesions surrounding the gut wall, such as the pancreato-biliary area, masses and lymph nodes. Fine-needle aspiration has become an indispensable adjunct to the technique since 1993, when it was shown to be feasible and safe to obtain tissue diagnosis in the majority of the lesions under the reach of endoscopic ultrasonography. In recent years, some authors have dealt with the practical clinical applications of endoscopic ultrasonography, validating its use in many diagnostic and staging algorithms and showing that it is cost-effective and significantly affects patient outcome.

Role of endoscopic ultrasonography in the diagnosis of early esophageal carcinoma

Endoscopic ultrasonography (EUS) for the diagnosis and staging of early esophageal carcinoma is discussed. Based on the nine-layered structure of esophageal wall, which is in good correspondence with histological layers, depth of carcinoma invasion can be investigated. Ultrasound endoscopes and probes are used for the examination. Ultrasound probes with 20 MHz and 30 MHz transducers can demonstrate the clear images of early esophageal carcinoma by using water filling method, which can discuss the change of the esophageal wall from the surface layer. Although the early esophageal carcinoma is detected by endoscopic findings with or without the dye spraying method by iodine, the diagnosis of depth of carcinoma invasion is not easy. EUS can assist in the diagnosis of depth of carcinoma invasion. Confirming the depth of carcinoma invasion by EUS and the lesion is limited to the mucosa. Endoscopists can decide the indication for endoscopic resection of the lesions.

Sensitive nerve receptors beneath the extensor apparatus of the hand fingers

In this paper we describe the finding of nervous receptors in the histologic layers beneath the extensor apparatus of the human fingers. Forty-eight fresh finger blocks of human corpses were processed and histological sections were stained with toluidine blue, hematoxylin-eosin, Masson's trichrome and silver staining for reticular fibres. These techniques showed the diverse kind of cells and tissues of the different layers previously described in another paper, and known as the extensor subtendinous digital aponeurosis and preperiosteal dorsal phalangeal fasciæ. We observed collagen fibres in the extensor apparatus and reticular fibres through all of these layers as well as typical fatty cells. Peripheral nerves and nervous receptors, like pacinian corpuscles, were found in the preperiosteal dorsal phalangeal fasciæ.

Chronic lithium treatment with or without haloperidol fails to affect the morphology of the rat cerebellum

We used unbiased stereological principles to determine whether long-term administration of lithium at human therapeutic levels, with or without haloperidol, affects the number or sizes of cerebellar Purkinje cells or the volume of histological layers in the rat cerebellum. Twenty-eight rats were randomly divided into three groups, receiving either no treatment, lithium, or lithium combined with haloperidol. The serum lithium levels ranged from 0.50 to 0.77 mmol/l. Haloperidol was given at a daily dose of 1 mg/kg. After 30 weeks of treatment, the animals were killed and the cerebelli were histologically prepared. No statistically significant differences were observed between the groups with respect to the cerebellar measures.

Small intestine wall distribution of elastic stiffness measured with 500 MHz scanning acoustic microscopy.

Obtaining data relating intestinal mechanical properties and histology is a step towards the next level in the hierarchy of structure of living tissue, and may provide new insight into the mechanisms of intestinal function and disease such as obstruction. Due to lack of methodology, however, such data are currently sparse. Scanning acoustic microscopy (SAM) can measure the propagation speed of sound (C) and the acoustic impedance (Z) with micrometer resolution in tissue. By use of elementary theory of elasticity, the elastic stiffness (c11) can be computed from C and Z. We used 5-microm-thick transverse sections of ethanol treated guinea pig small intestine as the experimental model and measured the distribution of C and Z across the intestinal wall using SAM at 500 MHz. The individual layers mucosa, submucosa, and circular and longitudinal muscle were discerned with ease in the images and varied significantly with respect to both C and Z in most cases. The measured values (median values) of C ranged from 1550 to 1669 m s(-1), and Z ranged from 2.10 to 2.60 MPa s m(-1). c11 differed between all layers ranging from 3.25 to 4.27 GPa with the following sequence of magnitude: circular muscle >submucosa>mucosa>longitudinal muscle (p<0.001). In conclusion, we provided the first microscale mechanical data relating to the histological layers of the small intestine.

EUS-guided fine-needle aspiration in the mediastinum

The evaluation and management of esophageal and mediastinal disease has changed considerably since the introduction of EUS. EUS provides precise imaging of the histologic layers of the esophageal wall and surrounding mediastinal structures. EUS is now a well-established modality for the staging of a variety of GI and pancreaticobiliary malignancies. Furthermore, it has been reported to play an important role in the evaluation of mediastinal lesions and in the detection of metastasis to lymph nodes.1-9 Traditionally, the mediastinum has been evaluated by radiographic imaging such as CT and by invasive studies like bronchoscopy and mediastinoscopy. Evaluation of the mediastinum using EUS has been reported to be useful for a number of indications. Most notable is the assessment of enlarged lymph nodes that are detected by other imaging modalities such as CT or magnetic resonance imaging. Probably the most important indication for mediastinal imaging is the detection and/or staging of lung cancer. Documentation of lymph node involvement with metastatic disease is crucial in the staging and management of non-small cell lung cancer (NSCLC). The introduction of the curved linear array echoendoscope approximately 8 years ago led to the development of EUS-guided fine-needle aspiration (FNA), which is now becoming recognized as an integral part of endosonography. EUS-guided FNA has been reported to be a safe and effective approach for evaluation of lymph nodes and masses in the posterior mediastinum.10-13 Tissue diagnosis from these lesions has been difficult to obtain by conventional methods such as mediastinoscopy, which is an invasive and tedious procedure, or percutaneous CT-guided puncture, which has a low yield and increased risk, especially in the case of smaller lesions.14 The objectives of this article are twofold: to discuss the clinical utility of EUS and EUS-guided FNA biopsy for evaluating the mediastinum in benign and malignant disease processes including the detection of posterior mediastinal lymph node metastases in patients with NSCLC and to describe the technique for performing safe EUS-guided FNA biopsy in the mediastinum.

Expression of structural proteins and angiogenic factors in cerebrovascular anomalies.

The goal of this study was to describe the expression of matrix proteins and angiogenic factors in cerebrovascular malformations. Forty-six cerebrovascular malformations were immunohistochemically investigated with a battery of staining for five structural proteins (collagen IV, collagen III, smooth muscle actin, fibronectin, and laminin), and three angiogenic factors (vascular endothelial growth factor [VEGF], basic fibroblast growth factor [bFGF], and transforming growth factor alpha [TGFalpha]). The lesions consisted of 34 arteriovenous malformations (AVMs), 10 cavernous malformations (CMs), and 2 venous angiomas. Expression intensity for each histological layer in the abnormal vessel wall was graded and compared. AVM endothelia and subendothelia expressed more laminin and collagen IV than the same layers of CMs. Conversely, CMs expressed more fibronectin than AVMs. CM endothelia exhibited more prominent staining for smooth muscle actin than AVM endothelia. AVMs and CMs expressed VEGF in the endothelium and subendothelium, and TGFalpha in endothelial and perivascular layers. However, unlike AVMs, CMs expressed bFGF in the endothelium as well. The brain tissue intermingled within AVMs also expressed growth factors. Modified glial cells in the brain tissue adjacent to CMs expressed bFGF and TGFalpha, but not VEGF. Venous angiomas did not express the studied growth factors and mainly consisted of structural proteins of angiogenically mature tissue. Expression characteristics of structural proteins reveal that AVMs and CMs have different immunohistological properties. This study provides strong confirmation of previous findings of VEGF and bFGF immunoexpression in AVMs and CMs. It adds new information on TGFalpha expression in these malformations and on expression of the angiogenic factors in venous angiomas.

3426 Spectrophotometry of colonic wall: which layers influence surface color on colonoscopy?

Background: Colonic surface color on endoscopy is largely determined by hemoglobin content in the colonic tissue, which has been calculated from spectral reflectance of the colonic surface as an index of hemoglobin (IHB). Histological colonic layers, influencing the surface reflectance has, however, still remained undetermined. Aims: The aim of this study was to determine the colonic layers, which influence the surface reflectance and the relative IHB against the total IHB in each colonic layer. Methods: Colonic tissue specimen with a gradation of thickness was constructed by using normal parts of resected colon from 5 patients with colorectal cancer. By using a spectrophotometer, spectral reflectance (410 to 690 nm) was measured at sampling points along a line of interest on the specimen at every 1mm intervals for IHB, which is give by 32Log (r650/r569). r650 and r569 designate reflectance at a wavelength of 650 and 569 nm, respectively. After photometry, the specimen was fixed in 10% formalin and sliced along the line of interest for a thickness of histological layers (micro-meter) in each sampling site. Results: IHB linearly increased to reach plateau as a thickness of the submucosa increased (Table). When a thickness of the submucosa exceeded 400 micro-meter, IHB remained constant, regardless of the presence or absence of deeper layers (propria muscle, subserosa and serosa). A thickness of the mucosa was found to have only least influence on IHB. The relative IHB against the total IHB was less than 45% for the mucosa and the remaining more than 55% for the submucosa. Conclusions: On colonoscopy, surface color was determined exclusively by the mucosa (45%) and submucosa (55%). In spectroscopy, it should be cautious to interpret IHB exclusively as mucosal hemoglobin especially in normal colon.

Correlation of laminated MR appearance of articular cartilage with histology, ascertained by artificial landmarks on the cartilage.

The object of this study was to correlate the laminae of articular cartilage on magnetic resonance (MR) imaging with histologic layers. T1- and fast spin-echo T2-weighted images of articular cartilage with artificial landmarks were obtained under high gradient echo strength (25 mT/m) conditions and a voxel size of 78 x 156 x 2000 microm. Images were also obtained with a) changed frequency-encoding directions; b) changed readout gradient strength; and c) a varied number of phase-encoding steps. T2 mapping was performed with angular variations. Artificial landmarks allowed accurate comparison between the laminae on MR images and the histologic zones. No alterations of the laminae were noted by changing the frequency gradient direction. Altering readout gradient strengths did not show a difference in the thickness of the laminae, and increasing the phase-encoding steps resulted in a more distinct laminated appearance, ruling out chemical shift, susceptibility, and truncation artifacts. The T2 mapping profile showed an anisotropic angular dependency from the magic angle effect. In conclusion, the laminated appearance of articular cartilage on spin-echo and fast spin-echo MR images correlated with the histologic zones rather than MR artifacts.

Morphological and histochemical ageing changes in patellar articular cartilage of the rat

The aim of this study was to investigate the variation in cartilage characteristics with age. Fresh-frozen cryostat sections of the patellar articular cartilage of the rat were used to demonstrate the enzyme activity of succinate dehydrogenase, lactate dehydrogenase, alkaline phosphatase, and acid phosphatase in the different layers and at different ages. Light microscopic techniques were used to analyse quantitative features such as thickness, cell density and the histological characteristics of the articular cartilage. The results indicate that cell density is significantly affected by age. Furthermore, it depends on the distance from the surface. The most marked decline in cell density occurred between months 3 and 6. The thickness of the articular cartilage also varies with age. The reduction in cartilage thickness was most striking between months 3 and 6. Differentiation into the histological layers is obvious after 3 months. Glycolytic enzymes were strongly reactive in all regions and at all ages, whereas aerobic activity declines with age. The metabolic and morphological changes in ageing cartilage contribute to trophic disorders and deterioration of the functional cartilaginous situation in adult cartilage.

Assessment of structural and functional similarities and differences between caeca of the bluegill

Bluegill Lepomis macrochirus possess six to eight gastrointestinal caeca, >70% having seven. The terminal caeca toward abdominal edge (C6, C7) were always larger than the terminal caeca toward the vertebral column (C1, C2) and middle caeca (C3, C4, C5). The caeca varied in relative thickness of the histological layers and lumen space. The terminal caeca (C1, C2, C6, C7) have anatomical positional advantage over, and possess more contents, than the middle ones (C3, C4, C5) in both field and laboratory conditions. Hence, all caeca in bluegill may have the same function but their functional potentials are not the same. Two factors, size of caeca and anatomical position of caeca, apparently work synergistically to cause variation in their functional efficiency.

Assessment of structural and functional similarities and differences between caeca of the bluegill

Bluegill Lepomis macrochirus possess six to eight gastrointestinal caeca, &gt;70% having seven. The terminal caeca toward abdominal edge (C6, C7) were always larger than the terminal caeca toward the vertebral column (C1, C2) and middle caeca (C3, C4, C5). The caeca varied in relative thickness of the histological layers and lumen space. The terminal caeca (C1, C2, C6, C7) have anatomical positional advantage over, and possess more contents, than the middle ones (C3, C4, C5) in both field and laboratory conditions. Hence, all caeca in bluegill may have the same function but their functional potentials are not the same. Two factors, size of caeca and anatomical position of caeca, apparently work synergistically to cause variation in their functional efficiency.

Staging of Gastric Cancer with Endoscopic Ultrasonography and Endoscopic Mucosal Resection

Since it was found that the gastrointestinal wall is visualized as a five-layered structure corresponding to the histological layers of the wall, endoscopic ultrasonography (EUS) has become recognized clinically as the most accurate method for diagnosing and assessing the local staging of gastric cancer. However, some problems have remained, including how to differentiate between cancer invasion and ulcer fibrosis, how to detect microinvasion, and how to recognize malignant lymph nodes. Using the pattern analysis for depressed-type gastric cancer, it is usually possible to distinguish between cancer invasion and ulcer fibrosis, except in cases of microinvasion into ulcer fibrosis or inadequate scanning. However, the sensitivity of EUS for evaluating metastatic lymph nodes is still problematic. Endoscopic mucosal resection (EMR) for early gastric cancer has been widely accepted as a standard treatment in Japan due to its minimal invasiveness. According to our data, the overall rate of radical resection was 68.3% (168 of 246), and 31.7% of the remaining patients additionally received laser treatment, surgery, or heater-probe treatment. There were no deaths owing to gastric cancer. Some lesions in which there was microinvasion of the submucosa were incorrectly diagnosed by EUS. It may be possible to solve this problem using three-dimensional EUS (3D-EUS) in the near future.

Histological correlates to pig gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope

BACKGROUND & AIMS: The magnetic resonance endoscope consists of a nonferromagnetic endoscope with a receiver coil incorporated into its tip. The aim of this study was to define the anatomic correlates of the gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope. METHODS: Twenty-two tissue specimens from various segments of the porcine gastrointestinal tract were imaged with the magnetic resonance endoscope using up to four different scanning sequences. Cyanoacrylate, serving as a marker, was randomly injected into the tissue strips before imaging. Histological sections were then compared with the magnetic resonance images. RESULTS: T1-weighted spin echo sequences yielded the highest image quality and typically showed three wall layers that corresponded to distinct histological layers. The mucosa showed high signal intensity, the submucosa low signal intensity, and the muscularis propria an intermediate signal intensity. In the esophagus and rectum, the muscularis propria could be visualized as separate circular and longitudinal layers. CONCLUSIONS: In vitro imaging with the magnetic resonance endoscope shows three to five wall layers of the porcine gastrointestinal tract depending on the segment scanned. This degree of gut wall resolution suggests that endoscopic magnetic resonance imaging may have potential for local staging of gastrointestinal tumors. (Gastroenterology 1997 May;112(5):1568-74)

Light dosimetry for photodynamic therapy in the esophagus.

Photodynamic therapy (PDT) is an efficient technique to treat superficial early cancers in the pharynx, esophagus, and tracheo-bronchial tree. However, the lack of selectivity of some of the clinically used photosensitizers can result in significant damage to the healthy tissue during the treatment. In the esophagus, this may lead to medical complications such as stenosis and fistula. Insufficient selectivity may be compensated to some extent by accurate light dosimetry. Here, we present an approach to safer and more efficient PDT by improved light dosimetry in the esophagus. This includes the utilization of a suitable light distributor, the estimation of the radiant energy density in the tissue, and the knowledge of the esophagus morphology. The light distributor presently used in the clinic is described and several techniques to study light propagation in the esophageal wall have been investigated and are discussed. Thickness of different histological layers of the esophageal wall have been measured ex vivo and are presented. Under these conditions and based on a simple model of the light distribution in the tissue, some basic and clinically useful notions of light dosimetry can be drawn. These notions, associated with measured value of tissue optical properties at the wavelengths of interest with the presently used photosensitizers, are discussed regarding the particular morphology of the esophageal wall. In particular, the importance of the illumination wavelength from the safety point of view is shown. The proposed approach allows for improved safety and efficacy of PDT in the esophagus, particularly in the clinical tests of new photosensitizers.

Localization studies of IGFBP-2 and IGFBP-5 in the anterior compartment of the eye

Purpose. Insulin-like growth factor binding proteins (IGFBPs) may modulate insulin-like growth factor-I (IGF-I) action and are important regulating factors in the IGF system. Our aim was to determine the presence of IGFBP-2 and -5 in the anterior compartment of the eye and to compare the histological sites of these IGFBP proteins with the respective IGFBP mRNAs. Methods. To investigate this, immunohistochemistry was used to detect the presence of IGFBP-2 and -5 proteins, and in situ hybridization was used to determine the presence of IGFBP-2 and -5 mRNAs. The studies were performed in normal adult male Sprague-Dawley rats. Immunohistochemistry was performed by the immunoperoxidase method with polyclonal anti-bovine-IGFBP-2 and antihuman-IGFBP-5 antibodies. In situ hybridization was performed using 35 S-radiolabelled riboprobes. Results. IGFBP-2 mRNA and protein were demonstrated in the outer non-pigmented ciliary epithelium, the corneal germinal epithelium and the corneal endothelium. IGFBP-2 mRNA was detected in these same histological layers of the ciliary processes and the cornea. IGFBP-5 mRNA localized to the stroma and also to the inner pigmented ciliary epithelium and IGFBP-5 protein was demonstrated in the adjacent outer non-pigmented ciliary epithelium. IGFBP-5 mRNA and protein were not demonstrated in the cornea. IGFBPs-2 and -5 were not demonstrated by immunohistochemistry in other structures of the eye. Conclusion. We have shown co-localization of IGFBP-2 mRNA and protein and adjacent cellular localization of IGFBP-5 mRNA and proteins in the anterior compartment of the eye. The presence of IGFBP-2 and -5 in the outer ciliary epithelium suggests secretion into the aqueous humour, where they may enhance trapping of IGF-I which may be important for lens and corneal cell survival. Our studies outlining the site of locally synthesized IGFBPs suggests specific roles in regulation of IGFs and highlights the potential importance of the IGF system in the eye.

Optical coherence tomography and microscopy in gastrointestinal tissues

Optical coherence tomography (OCT) and optical coherence microscopy (OCM) are novel techniques for noninvasive biomedical imaging based on low-coherence interferometry. OCT achieves high-spatial resolution ( 100 dB) in a fiber-optically integrated system which is suitable for application in minimally invasive diagnostics, including endoscopy. The technique of OCM combines the depth-ranging capability of OCT with the micron-scale resolution imaging capability of confocal microscopy to extend the available imaging depth of confocal microscopy up to several hundred micrometers deep in highly scattering tissues. The theoretical and technical bases for OCT and OCM imaging are described. Example OCT images are provided in gastrointestinal (GI) tissues to illustrate contrast between histological layers of the GI mucosa and differentiation of the mucosa from submucosa. Example OCM images revealing cellular-level microstructure up to several hundred micrometers deep in GI tissue are presented for the first time. The potential applications of OCT and OCM imaging in clinical diagnostic medicine are discussed.

MRI of the anal canal: correlation with histologic examination.

The purpose of this study was to correlate the MRI features of the anal canal with histologic findings. T1- and T2-weighted MR images of nine anal canals were obtained after fixation in 10% formalin. In three specimens, imaging was repeated after removal of histologic layers with a dissecting microscope. Corresponding histologic slices were stained with hematoxylin-eosin, Masson trichrome, and periodic acid-Schiff. Four layers were visualized on T2-weighted images. An inner layer of high signal intensity and a second layer of low signal intensity corresponded to the mucosa as well as mucous secretions and to the submucosa. The high signal intensity layer vanished at the distal part of the anal canal in accordance with the lack of mucus-secreting epithelium below the level of the dentate line. A third layer of intermediate signal intensity corresponded to the internal sphincter. A fourth layer of low signal intensity corresponded to the longitudinal muscle and external sphincter. T2-weighted MRI is capable of showing the internal architecture of the wall of the anal canal. In particular, the internal sphincter can be differentiated from the external sphincter and longitudinal muscle.

Intravascular ultrasound appearance of normal and mildly diseased coronary arteries: Correlation with histologic specimens

Intravascular ultrasound imaging was performed in vitro on six histologically normal and 104 minimally diseased arteries in patients aged 13 to 83 years. This study tested the hypothesis that normal coronary arteries produce a three-layer image that corresponds to the histologic layers of intima, media, and adventitia. The results showed a very good correlation between area of the echolucent ultrasound layer with the media and the inner echogenic layer with intimal area. In addition, a three-layer appearance was consistently seen when the internal elastic membrane was present with or without intimal hyperplasia. If the internal elastic membrane was absent, a three-layer appearance was still seen if the collagen content of the media was low. However, a two-layer appearance was observed when there was absence of the internal elastic membrane as well as a high collagen content of the media.

Morphology and distribution of microglial cells in the young and adult mouse cerebellum.

The morphology and distribution of microglial cells were studied in the normal cerebellum of young and adult mice using the histochemical demonstration of nucleoside diphosphatase as a specific microglial marker. Our results showed that microglial cells were present in all cerebellular lobules of both young and adult mice, but their distribution and morphology were not homogeneous throughout the cerebellum. Heterogeneity in microglial cell distribution was exclusively related to their location in the different histological layers, and no significant differences were found either between the different cerebellar lobules or between young and adult mice. Microglial density was higher in the cerebellar nuclei than in the cortex; within the cortex, the molecular layer was less densely populated by microglial cells than the granular layer and the white matter. The morphological study revealed that microglial cells were ramified in all cerebellar lobules of both young and adult mice but showed different sizes and ramification patterns as a function of their specific location in the different histological layers. Several typologies of microglial cells were described on the basis of observations in both horizontal and coronal sections. The specific layer-related pattern of microglial distribution and morphology in mouse cerebellum strongly suggests a physical and functional adaptation of these cells to the characteristics of their microenvironment.