Standard Histochemical Staining Research Articles

Virtual histological staining of unlabeled autopsy tissue

Traditional histochemical staining of post-mortem samples often confronts inferior staining quality due to autolysis caused by delayed fixation of cadaver tissue, and such chemical staining procedures covering large tissue areas demand substantial labor, cost and time. Here, we demonstrate virtual staining of autopsy tissue using a trained neural network to rapidly transform autofluorescence images of label-free autopsy tissue sections into brightfield equivalent images, matching hematoxylin and eosin (H&E) stained versions of the same samples. The trained model can effectively accentuate nuclear, cytoplasmic and extracellular features in new autopsy tissue samples that experienced severe autolysis, such as COVID-19 samples never seen before, where the traditional histochemical staining fails to provide consistent staining quality. This virtual autopsy staining technique provides a rapid and resource-efficient solution to generate artifact-free H&E stains despite severe autolysis and cell death, also reducing labor, cost and infrastructure requirements associated with the standard histochemical staining.

Smartphone‐based rapid and visual pathological diagnosis of glioma using perovskite probes

AbstractHistopathology plays a great role in diagnosing various diseases, which is considered as a golden standard for tumor identification. The tissue constituents must be stained by visible labels for microscopic analysis by medical experts. However, this process is time‐consuming, labor‐intensive, and expensive, which requires rapid pathological approaches for diagnosis in the operating room. Here, we present an easy‐to‐process and high‐performance perovskite biological probes for rapid and visual pathological diagnosis of glioma. Perovskite quantum dots can be encapsulated by the copolymer into nanocrystals (PNCs) with a diameter of 100 nm, which is modified with chlorotoxin to achieve the specific recognition of glioma. Benefiting from the super photoluminescence quantum yield (above 93%) of EVA@PNCs aqueous solution, the glioma can be clearly imaged and captured via a smartphone under the excitation of a handheld UV lamp. To demonstrate the visualization and efficiency of PNC probes, different malignant grades of brain tumor sections can be distinguished in no more than 5 min. This strategy provides a general auxiliary diagnosis platform for achieving the histopathology analysis near the operating bed, which is currently not feasible with standard histochemical staining methods.image

Clinicopathological significance of tubulointerstitial CD68 macrophages in proliferative lupus nephritis.

Tubulointerstitial macrophage plays a pathogenic role in renal damage of lupus nephritis (LN). However, the clinical and pathological role of these CD68 macrophages has not been fully described. The aim of the present study is to decipher the correlation between clinicopathological features and tubulointerstitial CD68 macrophages in 76 proliferative LN patients and further evaluate the prognostic significance of tubulointerstitial CD68 macrophages. Tubulointerstitial CD68 macrophages were quantitated by standard histochemical staining. The correlation between the number of tubulointerstitial CD68 macrophages and clinicopathological features was analyzed by Spearman's correlation analysis. Factors potentially affecting renal prognosis were further evaluated by Cox regression analysis. Among the 76 proliferative LN cases, the number of CD68 macrophage infiltrates was positively correlated with serum creatinine (SCr) level, the proportion of glomeruli sclerosis and focal segmental sclerosis, tubulointerstitial inflammation, and chronicity indices, while negatively correlated with the glomerular filtration rate. During a mean follow-up period of 45months, 5 patients (6.6%) progressed to dialysis, and 3 patents (3.9%) had a twofold increase in SCr. Multivariate Cox regression analysis showed that the number of tubulointerstitial CD68 macrophages was an independent variable associated with poor renal outcomes (HR = 1.002, P = 0.012). The optimal cutoff value of tubulointerstitial CD68 macrophages was 340/mm2 in our study with 87.5% sensitivity and 61.8% specificity to predict end-stage renal disease within 4years. The number of tubulointerstitial CD68 macrophages was positively linked to poor prognosis of LN. Urgent immunosuppression should be considered in LN patients with abundant tubulointerstitial CD68 macrophages. Key Points • Tubulointerstitial CD68 macrophage infiltrates are positively correlated with clinicohistologic impairment in proliferative lupus nephritis. • The positive association between the number of tubulointerstitial CD68 macrophages and poor renal outcome of lupus nephritis patients were observed. • Urgent immunosuppression and monitor are required when abundant tubulointerstitial CD68 macrophage infiltrates are detected.

Palisading granulomatous dermatitis and panniculitis (palisading granuloma) of dogs.

Palisading granulomatous dermatitis and panniculitis is recognized in various cutaneous inflammatory lesions secondary to presumed collagen damage. Cutaneous nodules with a palisading arrangement of histiocytes surrounding foci of collagen degeneration have been clinically termed palisading granuloma in dogs. Study aims were to characterize the cellular infiltrate of canine palisading granuloma and document salient clinical features. Inclusion criteria were met for 36 dogs and encompassed nodular dermal and subcutaneous histiocyte-predominant cellular infiltrates targeting and enveloping collagen fibers/necrotic foci with palisading configurations. Infectious causes were ruled out via standard histochemical stains and/or clinical data. Medical records were reviewed for signalment, clinical features, treatment, outcome, and comorbidities. Immunohistochemistry (IBA1, CD204, E-cadherin) and Masson's trichrome stain were used to assess histiocytic populations and dermal collagen, respectively. The histiocytes had moderate or strong immunolabeling for IBA1 and CD204 in 36/36 dogs (100%) and mild positive immunolabeling for E-cadherin in 3/36 dogs (8%). Alteration of collagen was graded as moderate or strong in 32/36 dogs (89%) and mild in 3/36 dogs (8%). Large breeds predominated with 30/36 dogs (83%) being ≥23 kg. Focal nodules were identified in 31/36 dogs (86%). The head/face were involved in 19/36 dogs (53%) and the extremities in 18/36 dogs (50%). Lesions from the 5/36 dogs (14%) with multiple nodules contained prominent eosinophilic infiltrates. Following excision, there was no evidence of recurrence. In conclusion, palisading granulomas are a distinct, non-neoplastic, histiocyte-predominant inflammatory condition in dogs associated with altered dermal collagen and favorable prognosis.

Association between tubulointerstitial CD8+T cells and renal prognosis in lupus nephritis

ObjectiveInflammatory cell infiltration is a pathological change commonly seen in renal biopsies from patients with lupus nephritis(LN), but its clinicalcorrelationwith clinical parameters and prognosis is unclear. MethodsIncluded in this retrospective study were 197 patients with ISN/ RPS Class III-V LN, in whom renal biopsy was performed to analyze the histological pattern. Tubulointerstitial infiltrates were quantitated by standard histochemical staining. Clinical and histologic variables were evaluated using a Cox proportional hazards model. End-stagerenaldisease(ESRD) progression was defined as a two-fold increase in serum creatinine (SCr) after biopsy, GFR decreased over 40%, initiation of dialysis, transplantation, or death. ResultsOf the 197 patients, 166 patients (84.3%) had proliferative LN. The number of tubulointerstitial infiltrates was the lowest in LN patients with ISN/RPS class V, and the number of CD68+ macrophages was the highest in all ISN/RPS classes of LN. In addition, the number of CD8+T cell infiltrates was positively correlated the SLEDAI sore, SCr level, proteinuria, the ratio of glomerulosclerosis and the degree of tubulointerstitial inflammation, interstitial fibrosis and tubular atrophy, activity and chronicity indices, and negatively correlated with C3 level at presentation. Multivariate survival analysis showed that tubulointerstitial CD8 + T cells > 130/mm2 was associated with ESRD progression (HR 1.007; 95% CI 1.003 to 1.011; p < 0.001). ConclusionTubulointerstitial CD8+T cells correlate with clinicohistologic impairment in LN. Tubulointerstitial CD8+T cells > 130/mm2 is independently associated with an unfavorable long-term kidney outcome.

In Silico Multi-Compartment Detection Based on Multiplex Immunohistochemical Staining in Renal Pathology.

With the rapid advancement in multiplex tissue staining, computer hardware, and machine learning, computationally-based tools are becoming indispensable for the evaluation of digital histopathology. Historically, standard histochemical staining methods such as hematoxylin and eosin, periodic acid-Schiff, and trichrome have been the gold standard for microscopic tissue evaluation by pathologists, and therefore brightfield microscopy images derived from such stains are primarily used for developing computational pathology tools. However, these histochemical stains are nonspecific in terms of highlighting structures and cell types. In contrast, immunohistochemical stains use antibodies to specifically detect and quantify proteins, which can be used to specifically highlight structures and cell types of interest. Traditionally, such immunofluorescence-based methods are only able to simultaneously stain a limited number of target proteins/antigens, typically up to three channels. Fluorescence-based multiplex immunohistochemistry (mIHC) is a new technology that enables simultaneous localization and quantification of numerous proteins/antigens, allowing for the possibility to detect a wide range of histologic structures and cell types within tissue. However, this method is limited by cost, specialized equipment, technical expertise, and time. In this study, we implemented a deep learning-based pipeline to synthetically generate in silico mIHC images from brightfield images of tissue slides-stained with routinely used histochemical stains, in particular PAS. Our tool was trained using fluorescence-based mIHC images as the ground-truth. The proposed pipeline offers high contrast detection of structures in brightfield imaged tissue sections stained with standard histochemical stains. We demonstrate the performance of our pipeline by computationally detecting multiple compartments in kidney biopsies, including cell nuclei, collagen/fibrosis, distal tubules, proximal tubules, endothelial cells, and leukocytes, from PAS-stained tissue sections. Our work can be extended for other histologic structures and tissue types and can be used as a basis for future automated annotation of histologic structures and cell types without the added cost of actually generating mIHC slides.

Digital synthesis of histological stains using micro-structured and multiplexed virtual staining of label-free tissue

Histological staining is a vital step in diagnosing various diseases and has been used for more than a century to provide contrast in tissue sections, rendering the tissue constituents visible for microscopic analysis by medical experts. However, this process is time consuming, labour intensive, expensive and destructive to the specimen. Recently, the ability to virtually stain unlabelled tissue sections, entirely avoiding the histochemical staining step, has been demonstrated using tissue-stain-specific deep neural networks. Here, we present a new deep-learning-based framework that generates virtually stained images using label-free tissue images, in which different stains are merged following a micro-structure map defined by the user. This approach uses a single deep neural network that receives two different sources of information as its input: (1) autofluorescence images of the label-free tissue sample and (2) a “digital staining matrix”, which represents the desired microscopic map of the different stains to be virtually generated in the same tissue section. This digital staining matrix is also used to virtually blend existing stains, digitally synthesizing new histological stains. We trained and blindly tested this virtual-staining network using unlabelled kidney tissue sections to generate micro-structured combinations of haematoxylin and eosin (H&E), Jones’ silver stain, and Masson’s trichrome stain. Using a single network, this approach multiplexes the virtual staining of label-free tissue images with multiple types of stains and paves the way for synthesizing new digital histological stains that can be created in the same tissue cross section, which is currently not feasible with standard histochemical staining methods.

Virtual histological staining of unlabelled tissue-autofluorescence images via deep learning.

The histological analysis of tissue samples, widely used for disease diagnosis, involves lengthy and laborious tissue preparation. Here, we show that a convolutional neural network trained using a generative adversarial-network model can transform wide-field autofluorescence images of unlabelled tissue sections into images that are equivalent to the bright-field images of histologically stained versions of the same samples. A blind comparison, by board-certified pathologists, of this virtual staining method and standard histological staining using microscopic images of human tissue sections of the salivary gland, thyroid, kidney, liver and lung, and involving different types of stain, showed no major discordances. The virtual-staining method bypasses the typically labour-intensive and costly histological staining procedures, and could be used as a blueprint for the virtual staining of tissue images acquired with other label-free imaging modalities.

Biopsy-proven renal disease in Ile-Ife, Nigeria: A histopathologic review.

Although various patterns of renal diseases have been reported from different renal biopsy registries worldwide, data from Nigeria remain scanty. A 10-year retrospective review of renal biopsies was conducted in our tertiary health care facility. All cases were reclassified based on their light microscopic features after the application of standard histochemical stains. A total of 165 cases were reviewed with a male:female ratio of 1.8:1 and a mean age of 15.4 ± 12.0 years. About 69.7% of the cases were below the age of 16 years, while only 2.4% were older than 50 years. The most common indications for biopsy were nephrotic syndrome (72.1%) and acute renal failure of unknown etiology (11.5%). Overall, glomerulonephritis (80%) was the most common histologic category and occurred only in individuals younger than 50 years old. Minimal change disease (22.9%) and membranoproliferative glomerulonephritis (21.9%) were the most common varieties in children, while membranous glomerulonephritis (30.6%) and focal segmental glomerulosclerosis (27.8%) were the commonest among the adult population. The initial histologic diagnosis was revised in 18 cases while a diagnosis was arrived at in seven cases initially adjudged as inadequate for assessment. This study showed that renal biopsy was predominantly performed in children and adolescents. Although glomerulonephritis was the predominant disease, the predominant histologic patterns varied with the patient age. Despite the scarcity of advanced diagnostic tools in resource-poor environments, routine use of histochemical stains is helpful in the evaluation of renal biopsies.

PMO-150 Second harmonic generation microscopy of collagen and evaluation of liver fibrosis in chronic hepatitis C (CHC) infection

IntroductionThere is an urgent need to create tools to quantify collagen in liver fibrosis to facilitate stratification of disease and development of anti-fibrotic agents. Multiphoton microscopy enables imaging of unstained...

Predicting outcomes of lupus nephritis with tubulointerstitial inflammation and scarring

In lupus nephritis, glomerular injury correlates poorly with progression to renal failure. While the tubulointerstitium is also commonly involved, the importance of such involvement is not well defined. Therefore, we developed a simple method to assess the prognostic utility of measuring tubulointerstitial inflammation (TI). Sixty-eight systemic lupus erythematosus patients with lupus nephritis were enrolled. Tubulointerstitial lymphocytic infiltrates were quantitated both by anti-CD45 antibody staining and standard histochemical staining. Followup data were obtained and survival analysis was carried out to determine which histologic features were predictive of subsequent renal failure. By CD45 staining, TI was a common pathologic finding, with 72% of biopsies having moderate or severe involvement. The extent of TI correlated with serum creatinine, but not with double-stranded DNA antibodies, serum C3, or glomerular inflammation. TI severity, but not glomerular injury, identified patients at greater risk for renal failure (P = 0.02). A high National Institutes of Health (NIH) chronicity index also identified patients at risk for renal failure. However, when the glomerular and tubulointerstitial subcomponents of the NIH chronicity index were separated in a bivariate model, only tubulointerstitial chronicity provided prognostic information (hazard ratio [HR] 2.2, 95% confidence interval [95% CI] 1.3-3.6; P = 0.002 versus HR 1.0, 95% CI 0.7-1.5; P = 0.97 for glomerular chronicity). TI identifies lupus nephritis patients at greatest risk for progression to renal failure. The immunologic mechanisms underlying TI may provide novel targets for therapeutic intervention.

Grey matter pathology in multiple sclerosis

Although multiple sclerosis (MS) has been considered a white matter disease, MS lesions are known to occur in grey matter. Recent immunohistochemical studies have demonstrated extensive grey matter demyelination in chronic MS. The most common lesion type consists of purely cortical lesions extending inward from the surface of the brain, this lesion subgroup is grossly underestimated by standard histochemical myelin staining methods. Some MS patients have subpial demyelination in all cortical areas of the brain; this pattern has been termed ''general cortical subpial demyelination''. Extensive cortical demyelination is associated with the progressive phases of disease, as less cortical demyelination has been detected in relapsing-remitting MS. The pathology of grey matter lesions differs from that of white matter lesions; grey matter lesions are less inflammatory, with less macrophage and lymphocyte infiltration. In purely cortical lesions there is no significant increase in lymphocytes compared with non-demyelinated adjacent cortical areas in MS patients or cerebral cortex in control patients. Significant axonal transection and neuronal loss have been demonstrated in grey matter MS lesions. Current magnetic resonance imaging (MRI) methods are not sensitive for purely cortical MS lesions. The clinical significance of cortical MS lesions may not be characterised until more sensitive MRI methods are developed.

Hypothermia during reperfusion does not reduce myocardial infarct size in pigs

We previously described a method for regional myocardial cooling that reaches the target temperature within 4 min. The present study evaluated whether this method for regional myocardial cooling during reperfusion reduces myocardial infarct size (IS) in 75-kg pigs. Myocardial infarction was induced by inflation of an angioplasty balloon in the left anterior descendent artery for 45 min followed by 3 h reperfusion. First, 15 pigs were randomized to regional myocardial cooling during reperfusion (n = 8) or control (n = 7). As further control experiments, systemic hypothermia was induced prior to ischemia (n = 3) and during reperfusion (n = 3). IS and area at risk (AAR) were evaluated in vivo by single photon emission cardiac tomography (SPECT) and by standard histochemical staining. Regional cooling during reperfusion did not reduce IS/AAR as assessed by histochemistry (cooling: 0.71 +/- 0.8; control: 0.68 +/- 0.10; p = ns) and SPECT (cooling: 0.90 +/- 0.20; control: 0.88 +/- 0.32; p = ns). Systemic hypothermia during ischemia reduced IS/AAR (histochemistry: 0.09 +/- 0.11; SPECT: 0.25 +/- 0.22; p < 0.001 and p = 0.01 vs control, respectively). Induction of systemic hypothermia during reperfusion had no significant effect on IS/AAR (histochemistry: 0.63 +/- 0.07; SPECT: 0.74 +/- 0.09; p = ns vs control for both comparisons). In conclusion, hypothermia during ischemia is strongly myocardioprotective while hypothermia during reperfusion does not reduce myocardial infarct size in human-sized pigs.

High-level transient expression of recombinant protein in lettuce.

Transient expression following agroinfiltration of plant tissue was investigated as a system for producing recombinant protein. As a model system, Agrobacterium tumefaciens containing the beta-glucuronidase (GUS) gene was vacuum infiltrated into lettuce leaf disks. Infiltration with a suspension of 10(9) colony forming units/mL followed by incubation for 72 h at 22 degrees C in continuous darkness produced a maximum of 0.16% GUS protein based on dry tissue or 1.1% GUS protein based on total soluble protein. This compares favorably to expression levels for commercially manufactured GUS protein from transgenic corn seeds. A. tumefaciens culture medium pH between 5.6 and 7.0 and surfactant concentrations < or = 100 ppm in the vacuum infiltration did not affect GUS expression, while infiltration with an A. tumefaciens density of 10(7) and 10(8) colony forming units/mL, incubation at 29 degrees C, and a surfactant concentration of 1,000 ppm significantly reduced expression. Incubation in continuous light caused lettuce to produce GUS protein more rapidly, but final levels did not exceed the GUS production in leaves incubated in continuous darkness after 72 h at 22 degrees C. The kinetics of GUS expression during incubation in continuous light and dark were represented well using a logistic model, with rate constants of 0.30 and 0.29/h, respectively. To semi-quantitatively measure the GUS expression in large numbers of leaf disks, a photometric enhancement of the standard histochemical staining method was developed. A linear relationship with an R2 value of 0.90 was determined between log10 (% leaf darkness) versus log10 (GUS activity). Although variability in expression level was observed, agroinfiltration appears to be a promising technology that could potentially be scaled up to produce high-value recombinant proteins in planta.

Bone marrow core biopsy specimens in AL (primary) amyloidosis. A morphologic and immunohistochemical study of 100 cases.

We retrospectively reviewed 100 bone marrow core biopsy specimens from patients with AL (primary) amyloidosis. The morphologic and immunohistochemical features were assessed by standard histochemical stains (H&E, periodic acid-Schiff, Congo red) and immunohistochemical stains for light chain immunoglobulins. Bone marrow core biopsy revealed a plasma cell dyscrasia in 83% (lambda, 65; kappa, 18) of cases. Amyloid deposits were observed in 60% of the bone marrow core biopsy specimens and, when present, were detected most often in blood vessel walls only (39/60). However, if present, interstitial amyloid deposition was significantly more associated with patients with a monoclonal kappa light chain gammopathy (P = .04). Through the careful analysis of standard histochemical and immunohistochemical stains, bone marrow core biopsy provides essential diagnostic information in cases of AL amyloidosis.

Bone Marrow Core Biopsy Specimens in AL (Primary) Amyloidosis

We retrospectively reviewed 100 bone marrow core biopsy specimens from patients with AL (primary) amyloidosis. The morphologic and immunohisto-chemical features were assessed by standard histochemical stains (HEκ, 18) of cases. Amyloid deposits were observed in 60% of the bone marrow core biopsy specimens and, when present, were detected most often in blood vessel walls only (39/60). However, if present, interstitial amyloid deposition was significantly more associated with patients with a monoclonal κ light chain gammopathy ( P = .04). Through the careful analysis of standard histochemical and immunohistochemical stains, bone marrow core biopsy provides essential diagnostic information in cases of AL amyloidosis.

Minimal ischaemic neuronal damage and HSP70 expression in MF1 strain mice following bilateral common carotid artery occlusion

Investigation into the influence of specific genes and gene products upon the pathophysiology of cerebral ischaemia has been greatly enhanced by the use of genetically modified mice. A simple model of global cerebral ischaemia in mouse is bilateral common carotid artery occlusion (BCCAo) and the neuropathological impact of BCCAo has been investigated in several mouse strains. Bilateral carotid occlusion produces extensive neuronal damage in C57Bl/6J strain mice and this damage is linked to posterior communicating artery (PcomA) hypoplasticity in the circle of Willis. In the present study, we investigated the effect of BCCAo in MF1 strain mice and compared them with C57Bl/6J mice. The neuropathological consequences of BCCAo were assessed using standard histochemical staining and heat shock protein 70 (HSP70) immunohistochemical staining (to demarcate cells that had been ischaemically stressed). The effect of BCCAo on mean arterial blood pressure (MABP) was also measured. The plasticity of the circle of Willis was recorded using carbon black perfusion. MF1 mice displayed significantly less ischaemic neuronal damage and HSP70 immunoreactivity compared to C57Bl/6J mice following 10–20 min BCCAo. Moreover, ischaemic neuronal damage and HSP70 immunoreactivity in MF1 mice subjected to extended BCCAo (25–45 min) was never as extensive or widespread as that observed in C57Bl/6J mice after 20 min BCCAo. MABP in MF1 mice (102±5 mmHg) was significantly higher than in C57Bl/6J mice (87±5) during 20 min BCCAo. MABP in MF1 mice during 20 and 40 min (103±12 mmHg) BCCAo remained above pre-occlusion values for the entire occlusion period. MF1 mice had significantly greater circle of Willis plasticity (more PcomAs) than C57Bl/6J mice did. These data indicate that MF1 mice are less susceptible to BCCAo than C57Bl/6J mice and that this could be due to maintained increases in MABP during BCCAo and the lower prevalence of abnormalities of the circle of Willis in MF1 mice.

Muscle adaptation of Thoroughbred racehorses trained on a flat or sloped track

Abstract Objective To determine histochemical and biochemical properties of muscle during adaptation to training on a flat or sloped track. Animals 22 Thoroughbreds. Procedure Samples were obtained from the middle gluteus muscle before and after training programs were conducted, using a needle-biopsy technique. Training programs consisted of horses running 1,600 m on a flat or sloped track for 16 weeks. Amplitude of middle gluteus muscle activity per burst was calculated. Muscle fiber composition and area were examined on serial cross sections processed by standard histochemical staining procedures (ATPase stain after prior incubation with an acid or base, followed by succinate dehydrogenase [SDH] stain). Furthermore, SDH and phosphofructokinase activities were determined biochemically, and composition of myosin heavy chain (MHC) isoforms was analyzed electrophoretically. Results Training resulted in substantial adaptations. Relative contribution of muscle fiber with high SDH activity (type-I and -IIa fibers) to total cross-sectional area, SDH activity, and composition of MHC-IIa isoforms were increased. Gel electrophoresis revealed a large amount of MHC-IIx isoform and a small amount of MHC-IIb isoform in the muscle. Although root mean square of muscle activity for training on a sloped track was 7.6% higher than the value obtained while training on a flat track, muscle histochemical and biochemical properties did not differ significantly between groups training on flat and sloped tracks. Conclusions Training adaptations for contractile and metabolic properties of the middle gluteus muscle were evident for the 2 types of training. However, training adaptations did not differ significantly between groups trained on flat or sloped tracks. (Am J Vet Res 1999;60:1536–1539)

Morphological and histochemical variations of mucous and oxynticopeptic cells in the stomach of the seps, Chalcides chalcides

Mucous and oxynticopeptic cells in the gastric mucosa of the seps, Chalcides chalcides (Linnaeus, 1758) were examined by standard histochemical staining methods and by lectin histochemistry. The epithelial mucous cells lining the surface of the stomach and the mucous cells of the fundic glands elaborated mainly neutral glycoproteins with β(1,4)GlcNAc oligomers, GalNAc glycosidic residues and Galβ1,3GalNAc terminal sequences. The mucous cells of the fundic glands were stained specifically with the Paradoxical Con A method. The mucosecreting cells of the pyloric glands produced neutral glycoproteins, with β(1,4)GlcNAc oligomers, GalNAc residues and Galβ1,3GalNAc terminal sequences. Terminal L-fucose bound to the penultimate GlcNAc residues, and/or difucosylated oligosaccharides were also present. The pyloric glands did not stain with the Paradoxical Con A procedure. The morphology of the oxynticopeptic cells changes from the oral to the aboral region of the fundic mucosa. In the oral fundic tract the oxynticopeptic cells showed cytoplasm filled with zymogen granules, while in the aboral fundic region these cells contained few zymogen granules and showed cytoplasm full of empty vesicles, typical of the acid secreting cells. A secretion gradient of proteolytic enzymes and hydrochloric acid along the fundic mucosa of the seps can be hypothesised.

Morphological and histochemical variations of mucous and oxynticopeptic cells in the stomach of the seps, Chalcides chalcides.

Mucous and oxynticopeptic cells in the gastric mucosa of the seps, Chalcides chalcides (Linnaeus, 1758) were examined by standard histochemical staining methods and by lectin histochemistry. The epithelial mucous cells lining the surface of the stomach and the mucous cells of the fundic glands elaborated mainly neutral glycoproteins with beta(1,4)GlcNAc oligomers, GalNAc glycosidic residues and Gal beta1,3GalNAc terminal sequences. The mucous cells of the fundic glands were stained specifically with the Paradoxical Con A method. The mucosecreting cells of the pyloric glands produced neutral glycoproteins, with beta(1,4)GlcNAc oligomers, GalNAc residues and Gal beta1,3GalNAc terminal sequences. Terminal L-fucose bound to the penultimate GlcNAc residues, and/or difucosylated oligosaccharides were also present. The pyloric glands did not stain with the Paradoxical Con A procedure. The morphology of the oxynticopeptic cells changes from the oral to the aboral region of the fundic mucosa. In the oral fundic tract the oxynticopeptic cells showed cytoplasm filled with zymogen granules, while in the aboral fundic region these cells contained few zymogen granules and showed cytoplasm full of empty vesicles, typical of the acid secreting cells. A secretion gradient of proteolytic enzymes and hydrochloric acid along the fundic mucosa of the seps can be hypothesised.