Acid Mucosubstances Research Articles

Angelica sinensis polysaccharide facilitates chondrogenic differentiation of adipose-derived stem cells via MDK-PI3K/AKT signaling cascade

ObjectAdipose-derived mesenchymal stem cells (ADSCs) have received significant attention in the field of cartilage tissue repair. Angelica sinensis polysaccharide (ASP) can enhance both the proliferation and differentiation of mesenchymal stem cells. Therefore, we intend to explore the effect of ASP on chondrogenic differentiation of ADSCs in vitro, and elucidate the underlying mechanisms. MethodADSCs were treated with different concentrations of ASP to determine the optimal concentration. The chondrogenic differentiation of ADSCs was evaluated using Alcian blue staining, qRT-PCR, western blot, and IF staining. Transcriptome sequencing was performed to identify the expression profiles of ADSCs before and after ASP treatment, followed by bioinformatic analyses including differential expression analysis, enrichment analysis, and construction of PPI networks to identify differentially expressed genes (DEGs) associated with ASP and chondrogenic differentiation. ResultSurface markers of isolated rat-derived ADSCs were identified by CD44+CD90+CD45-CD106-, and exhibited the capacity for lipogenic, osteogenic, and chondrogenic differentiation. With increasing concentration of ASP treatment, there was an upregulation in the activity and acidic mucosubstance of ADSCs. The levels of Aggrecan, COL2A1, and Sox9 showed an increase in ADSCs after 28 days of 80 µg/ml ASP treatment. Transcriptome sequencing revealed that ASP-associated DEGs regulate extracellular matrix synthesis, immune response, inflammatory response, and cell cycle, and are involved in the NF-κB, AGE-RAGE, and calcium pathways. Moreover, Edn1, Frzb, Mdk, Nog, and Sulf1 are hub genes in DEGs. Notably, ASP upregulated MDK levels in ADSCs, while knockdown of MDK mitigated ASP-induced elevations in acidic mucosubstance, chondrogenic differentiation-related markers (Aggrecan, COL2A1, and Sox9), and the activity of the PI3K/AKT pathway. ConclusionASP enhances the proliferation and chondrogenic differentiation of ADSCs by activating the MDK-mediated PI3K/AKT pathway.

Comparative Nutritional and Histological Analysis of Malabar Red Snapper (Lutjanus malabaricus) and Asian Seabass (Lates calcarifer).

This study offers a comprehensive morpho-histological analysis of the gastrointestinal tract (GIT) of the Malabar red snapper. A comparison of its GIT morphology with that of the Asian seabass reveals similarities and differences between the two species. Additionally, the moisture content, crude protein, and ash in the fillets of Malabar red snapper and Asian seabass were slightly different, with Malabar red snapper exhibiting higher levels of essential fatty acids. Furthermore, higher levels of the polyunsaturated fatty acid (PUFA)/saturated fatty acid (SFA) ratio and docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio, and a lower omega-6/omega-3 ratio, were observed in Malabar red snapper compared to Asian seabass. The Malabar red snapper's esophagus featured protective mechanisms such as simple columnar epithelial cells, mucous-secreting glands, and goblet cells that were predominantly stained for acid and neutral mucosubstances. Furthermore, its stomach, with mucus cells that were weakly stained for acid mucosubstances, exhibited distinct regions with varying glandular densities, with the pyloric region featuring few glands. The pyloric caeca of the fish were composed of five finger-like structures and few goblet cells. Several goblet cells gradually increased from the anterior to the posterior region of the intestine. These findings provide useful insights for the aquaculture sector, focusing on Malabar red snapper.

Light and Electron-Microscopic Studies on the Paraepiglottic Tonsil of the Buffalo (Bubalus bubalis)

The paraepiglottic tonsil present on either side of the base of the epiglottis constitutes a small portion of the mucosa-associated lymphoid tissue. The present study was conducted on the paraepiglottic tonsils of 12 adult buffaloes of the local mixed breed to explore its basic histomorphological, histochemical, and ultrastructural characteristics and to compare with other tonsils of the oral region to ascribe immunological function. The tonsil mucosa was lined by partly stratified squamous keratinised epithelium towards the outer surface and a stratified squamous non-keratinised epithelium towards the shallow crypts. The non-keratinised epithelium modified into reticular type due to infiltration of underlying lymphoid tissue was characterised by the predominance of the lymphoid cells, interrupting basement membrane and indistinct strata. The reticular epithelium at places presented a spongy appearance. The loose irregular connective tissue of propria-submucosa was mainly comprised of glandular and lymphoid tissue. The lymphoid tissue was mainly in the form of isolated lymphocytes, diffuse aggregations, and lymphoid follicles. The inter-follicular areas showed the presence of high endothelial venules. The sero-mucous type of glandular acini presented a strong reaction for glycogen, acidic mucosubstances, weakly sulfated mucosubstances, mucin, and the presence of more than 4% cysteine in their secretions. The tonsils under scanning electron microscopy presented an undulating appearance due to the presence of crest and folds. Higher magnification revealed squamous cells having various patterns and arrangements of microplicae. Small pits visualised on the mucosal surface represented openings of the glandular ducts. The cells towards the lumen of some glandular ducts appeared whorl-like where typical microplicae were absent. The transmission electron microscopy of different strata of different types of epithelia showed varying cell organelles, especially the mitochondria, endoplasmic reticulum, Golgi apparatus, and few filaments. The structural features of the tonsil were similar to those of other oral tonsils and suggested their immunological role, which might be of importance to local immunity.

Digestive tube of an herbivorous fish (Rhytiodus microlepis) from the Amazonian floodplain lakes: A morphological and histochemical study.

This study describes the morphology and histochemistry of the digestive tube of the herbivorous fish Rhytiodus microlepis, which is commonly found in the Amazonian floodplain lakes, Brazil. Thirty-eight fish were used in this study. The digestive tube was measured and dissected for anatomical description, and stained with (i) haematoxylin and eosin, for histological analyses; (ii) periodic acid-Schiff, for detected neutral mucins; and (iii) Alcian Blue (AB) pH 1.0 and 2.5 for acid and sulphated acid mucins. The oesophagus, with its secretory cells and taste buds, is adapted for lubrication of vegetable matter, resistance to friction and reception of stimuli. The stomach is U-shaped and rich in gastric glands, particularly in cardiac and fundic regions, which are adapted to receive large amounts of food, and promotes the digestion. The intestine comprises more than 70% of the digestive tube. All portions of the intestine, except the rectum, have the same pattern of mucosal folds, and the goblet cells reacted positively to all histochemical methods (PAS, AB 1.0 and 2.5), while rodlet cells reacted only to periodic acid-Schiff (PAS) staining. Neutral mucins and sulphated acid mucins predominated in the anterior portion of the intestine and a high concentration of carboxylated acid mucosubstances were present in the other portions. The rectum showed a strong reaction to all histochemical methods. The muscular layer of the intestine consists of three layers, which showed features presumably related to the rigid nature of the food. A simple squamous epithelium constitutes the serous layer over the entire length of the tube.

Detailed comparative anatomy of the Pinnidae (Mollusca, Bivalvia) reveals further unusual mantle specializations

Pinnids are semi-infaunal bivalves with several unusual morphological features, some of them regarded as adaptations to environments with high concentration of suspended particles. The presence of a waste canal on the mantle wall, for example, helps rejecting surplus particles from the mantle cavity. Despite being such anatomically intriguing bivalves, detailed comparative morphology studies on pinnids are still scarce. To gain further insights into the functional anatomy of pinnids, we have thoroughly investigated the mantle of Pinna carnea Gmelin, 1791 by means of scanning electron and light microscopy, including the application of histochemical staining methods. Additionally, the mantle was analyzed in ten pinnids from the genera Atrina, Pinna, and Streptopinna obtained in museum collections. Comparative morphology revealed a uniform structural organization of the mantle in Pinnidae, but a pronounced variation in pigmentation, presence of commarginal folds, and papillae. Our results also revealed intense secretory activity in the inner mantle fold, inner mantle epithelium, and waste canal, including at least three secretory cell types. Secretions are diverse and comprise mainly acidic mucosubstances on the mantle margin, while the waste canal secretes abundant acidophilic material apparently composed of basic proteins, and also possibly lipid content. Based on these results, we hypothesize that efficient mucociliary transportation is achieved in a hydrophobic environment provided by the waste canal, rapidly agglutinating and removing large amounts of particles from the mantle. Discoid glands secreting protein-rich content were found on the middle mantle fold of Pinna carnea and Streptopinna saccata (Linnaeus, 1758). Surprisingly, these mantle glands have hitherto not been recorded in the Bivalvia, representing, therefore, a new morphological feature in the Pinnidae.

Mantle histology and histochemistry of three pearl oysters: Pinctada persica, Pinctada radiata and Pteria penguin

ABSTRACTShells in pearl oysters are produced by the mantle which is also used as a graft in pearl operations. Here, we investigate the mantle structure of a new pearl oyster species of the Persian Gulf, Pinctada persica, and compare it to two other pearl-producing species, Pinctada radiata and Pteria penguin. The anterior, ventral and posterior segments of the mantle edge of each valve were fixed, and tissue sections were stained with haematoxylin and eosin. A new pentachrome method and PAS-alcian blue staining were used to characterise the different mucosubstances. The mantle edges were found to have an outer, middle and inner fold, which have different morphology in each species. The mantle edge is lined by cuboidal and columnar epithelia, and interspersed among these epithelial cells we found mucous cells and cells that contained brown granules. The outer and middle folds of the two Pinctada species show different shapes to that of Pteria penguin. Most of the mucous cells in the mantle contain acidic mucosubstances and small amounts of mixed acidic-neutral mucosubstances were observed in the middle and inner fold of Pinctada persica. This study reveals that the mantle edges of the three species possess similar cellular structure, but vary in the shape of the folds.

Effect of Melittin on collagen type II expression of rat endplate chondrocytes induced by interleukin 1β

To observe the effect of Melittin on collagen type II (Col-II) expression of rat endplate chondrocytes (EPCs) induced by interleukin 1β (IL-1β). Primary EPCs from the lumbar vertebra of 4-week-old Sprague Dawley rats were cultured in vitro and identified by morphological observation, toluidine blue staining and Col-II immunofluorescence staining. Then, MTT assay was used to determine the optimal concentration of IL-1 and Melittin. Next, EPCs at passage 3 were randomly divided into 4 groups: no treatment was done in group A as control group; the optimal concentration of IL-1β, Melittin, and both IL-1β and Melittin were used in groups B, C, and D respectively. The expression of Col-II was detected by Western blot after 48 hours intervention. Under inverted microscope, the first generation EPCs were polygonal; cell proliferation decreased after fifth generation, and cell morphology changed into fusiform. The acidic mucosubstance in the cytoplasm (such as Aggrecan) was stained dark blue by toluidine blue. After marking Col-II by immunofluorescence, the positive expression of cytoskeleton (green fluorescence) could be observed. MTT assay showed that IL-1β and Melittin could inhibit the EPCs in a dose-dependent manner after intervention of 24 and 48 hours, and the optimal concentrations of IL-1β and Melittin intervention were 10 ng/mL and 1.0 μg/mL respectively. Compared with group A, the expression of Col-II was significantly reduced in group B, and was significantly increased in group C by Western blot assay, but there was no significant difference between group D and group A. The Col-II expression levels of groups A, B, C, and D were 0.991±0.024, 0.474±0.127, 1.913±0.350, and 1.159±0.297 respectively, showing significant difference between the other groups ( P<0.05) except between group A and group D ( P>0.05). Melittin has a protective effect on endplate cartilage, and the research results provide experimental basis for the prevention and treatment of spinal degenerative disease.

Effects of estrogen on esophageal function through regulation of Ca2+-related proteins.

The calcium ion is important for physiological functions in all tissues and organs and essential to many vital functions, including hormone secretion and muscle contraction. The intracellular concentration of calcium is regulated by calcium related proteins such as CaBP-9k, PMCA1, and NCX1. In this study, we investigated the relationship between calcium regulation and esophageal functions such as mucin secretion and smooth muscle contraction. To evaluate the influence of sex steroid hormones, immature rats were treated for 3days with estradiol (E2), progesterone (P4), and their antagonists (ICI 182,780, and RU486). Esophageal function, transcription level, and localization of CaBP-9k, PMCA1, NCX1, ERα, and MUC2 were examined in the esophagus. Transcriptional level of Cabp-9k and Muc2 was increased by E2, but not by P4. CaBP-9k, PMCA1, and MUC2 were mainly localized in the mucosal layer. Acidic mucosubstances in the esophagus were increased by E2 and recovered by ICI treatment. Unlike the expression of Cabp-9k, mRNA levels of Pmca1, Ncx1, and Erα were only decreased in response to E2, and recovered by ICI co-treatment group. The contraction of the esophagus and mRNA level of Mylk were reduced by E2. Overall, E2 upregulated mucus secretion, but downregulated muscle contraction in the esophagus through regulation of the expression of calcium related genes and the resultant intracellular calcium level. The regulation of E2 in the function of esophagus may be applied to treat esophageal diseases such as reflux esophagitis, achalasia, and esophageal cancer.

Comparative histochemistry of posterior lingual salivary glands of mouse

Normal posterior deep and superficial salivary glands of tongue were examined in male mice by means of light microscopical histochemistry and neurohistology. Both glands showed acini and simple ducts. Demilunes were present in the superficial gland. Disulphides and neutral mucosubstances occurred in acini and demilunes. Tryptophan staining was seen in acini of the deep gland and demilunes, whereas acid mucosubstances were exclusively localised in the superficial gland. Dehydrogenase activities were widespread. Strong esterase activity occurred throughout the parenchyma of the deep gland and in demilunes; it was variably inhibited by E600, apart from acinar apical regions in the deep gland. Lipase was confined to acini of the deep gland and demilunes. Acid phosphatase staining was similarly localised; it was also seen in periluminal ductal rims of the deep gland, in which ouabain-sensitive Na,K-ATPase was localised basolaterally. Staining for alkaline phosphatase decorated occasional myoepithelial-like arrangements and interstitial capillaries. Acetylcholinesterase was associated with nerve fibres embracing glandular parenchyma. Adrenergic fibres were not seen. The results suggest that the acini of the posterior deep lingual gland secrete neutral glycoproteins, whereas the ducts transport ions and absorb luminal material. The posterior superficial lingual gland mainly secretes acid glycoproteins. Both glands produce lingual lipase, receive cholinergic-type innervation and have inconspicuous myoepithelium.

Microanatomy of the digestive system of Supachai's caecilian,Ichthyophis supachaiiTaylor, 1960 (Amphibia: Gymnophiona)

AbstractThe gross anatomy and microanatomy of the digestive system ofIchthyophis supachaiiwere investigated. The microscopic structures of the digestive system are similar to those in other caecilians. Functional and developing teeth are present in adults. The tongue contains the genioglossus muscle. The digestive tract is elongated and consists of the mucosa, submucosa, muscularis and adventitia/serosa. The oesophagus contains longitudinal folds and lacks oesophageal glands. We report for the first time the caecilian gastric rugae and specific localization of oxynticopeptic cells in the anterior gastric region. The intestinal folds are exclusively present in the anterior intestinal region. The liver comprises 30–40 incomplete hepatic lobes, lying in an imbricate manner. Each lobe is enveloped by haematopoietic tissue that produces and delivers blood cells into sinusoids. Hepatic parenchyma is organized into anastomosing, two‐cell‐thick plates, having sinusoids at the basal domain and bile canaliculi at the apical domain of hepatocytes. Pigment cells are scattered inside sinusoids. The pancreas contains pancreatic acini interspersed with islets of Langerhans. The gallbladder proper is thin and continuous with the cystic duct wall. Neutral and carboxylated acid mucosubstances are secreted along the digestive tract, while sulphated mucosubstances are not produced by the stomach and anterior intestinal regions.

A histological and histochemical study of the small intestine of the dromedary camel (Camelus dromedarius)

This study was aimed at the investigation of the histological and histochemical features of the small intestine in the one-humped camel (Camelus dromedarius), in view of the metabolic characteristics of this species. For this purpose, the duodenum, jejunum and ileum of 6 healthy adult camels were used. Microscopic examination revealed that the length of the mucosal folds (villi) decreased progressively from the duodenum to the ileum. The deepest crypts were observed in the duodenum (P<0.001) and the longest villi were detected in the jejunum (P<0.001). Villi with the largest crypt diameter were observed in the ileum (P<0.001). The small intestine epithelium consisted of 3 parts: the tip of the villus intestinalis, the villus-crypt space and the crypt base. These parts were examined for their histochemical features, and data were evaluated subjectively. Goblet cells were rich in neutral carboxylic acidic mucosubstances and poor in sulfated acidic mucosubstances. While the concentration of the neutral mucosubstances was higher at the tip of the villi, the concentration of the acidic mucosubstances was higher in the crypts. The present study describes the histological/histochemical structure of the small intestine in the one-humped camel (Camelus dromedarius) and thereby, provides an opportunity for the comparison of findings obtained in camels and other ruminant species.

Histology and ultrastructure of the caudal courtship glands of the red-backed salamander, Plethodon cinereus (Amphibia: Plethodontidae).

Caudal courtship glands (CCGs) are sexually dimorphic glands described in the skin of the dorsal tail base of some male salamanders in the genera Desmognathus, Eurycea, and Plethodon in the family Plethodontidae. These glands are believed to deliver pheromones to females during courtship, when the female rests her chin on the dorsal tail base during the stereotypic tail straddling walk unique to plethodontids. Although CCGs have been studied histologically, no investigations of their ultrastructure have been made. This article presents the first study on the fine structure and seasonal variation of CCGs, using the plethodontid Plethodon cinereus. The CCGs vary seasonally in height and secretory activity. The mature secretory granules observed in males collected in October and April consist of oval, biphasic granules that are eosinophilic and give positive reactions to periodic acid-Schiff for neutral carbohydrates but do not stain for acidic mucosusbtances or proteins with alcian blue and bromphenol blue, respectively. Granular glands, some of which contain mucous demilunes, are twice as large as CCGs, are syncytial (unlike CCGs), and stain for proteins. Mucous glands are similar in size to CCGs, but are basophilic, show no seasonal variation in secretory activity, and stain positive for acidic mucosubstances. CCGs do not resemble cytologically the sexually dimorphic mental glands of some plethodontids, which contain round or oval granules filled with an electron-dense amorphous substance. The CCGs are similar histologically to sexually dimorphic skin glands described in some anurans, but more comparative work is needed.

Comparative Studies on the Tongue of White-throated Kingfisher (Halcyon smyrnensis) and Common buzzard (Buteo buteo)

The aim of the current study was to investigate and evaluate the ultrastructural and histological aspects of the tongue as well as the histochemical features of the lingual salivary glands of the white-throated kingfisher (Halcyon. smyrnensis); a piscivorous bird and common buzzard (B.buteo); an omnivorous bird. The tongues of the two selected species were investigated in an attempt to elucidate whether variations in the nature of diet may associate with special adaptive lingual structures. Six animals of each studied species were used for the present work. The observed results elucidated that, the tongue of white-throated kingfisher was triangular and occupied 1/2 length of the beak while, the tongue of common buzzard was elongated and biforked at its apex and occupied 2/3 length of the beak. The tongue of common buzzard was longer than that of H. smyrnensis. Morphologically, three parts were distinguished in the dorsal surface of the tongue for the two studied species: the apex, the body and the root. The results showed numerous fine hard processes on dorsal surface of H.smyrnensis tongue. On the other side, such processes were apparently absent in the tongue of common buzzard. The dorsal surface of common buzzard tongue was keratinized. In contrast, such keratinization was absent in the tongue of white-throated kingfisher. The recorded results manifested that the salivary glands of both species were mostly simply branched tubular that open on the surface of epithelium by glandular orifices. The glands were well developed and widely distributed in the lingual mucosa of the common buzzard in compared with those of white-throated kingfisher. However, the latter species showed a unique feature that represented by existence of numerous simple tubular mucus glands arranged as one raw on the dorsal lingual epithelium. In addition, the present findings indicated that, the lamina propria of H.smyrnensis tongue had connective tissue and filiform papillae. In particular, the dorsal surface at junction between the lingual body and root of H.smyrnensis was covered by pseudostratified ciliated columnar epithelium. The histochemical investigations revealed that, the salivary glands were made of mucoserous cells that elaborate neutral mucosubstances, acid mucosubstances and proteins, in which the glands of H. smyrnensis showed stronger reaction for neutral and acid mucosubstaces and weaker reaction for protein comparing to those of common buzzard.

Tu1764 The Effects and Mechanism of Esophageal Acid Exposure on Trachea Mucous Production

In prior studies we found that esophageal acid exposure caused a small decrease in airway diameter, an increase in tracheobronchial mucus secretion, and a decrease in mucociliary transport rate. However, the store of mucus is not large and can easily be depleted, therefore, we hypothesized that mucus production may be under physiological control. AIM: To determine whether a physiological stimulus can affect mucus production and to investigate the mechanism of this effect. METHODS: Sixteen cats were anesthetized using alphachloralose. The esophagus was ligated 3-4 cm from the UES and the esophagus proximal and distal to the ligation was cannulated. Either the proximal (N=8) or distal (N=8) esophagus was perfused using 0.1N HCl for 30 min followed by 30 min of PBS while the opposite esophageal segment was perfused with PBS for 60 min. The trachea was excised, fixed, sliced at 5μ, and stained with Periodic Acid Schiff (PAS)-Alcian Blue (AB) at pH 1.0. The areas of neutral (PAS-positive) and acidic (AB-positive) mucosubstances in the epithelial and submucosal mucous glands of the trachea adjacent to the proximal and distal cervical segments of esophagus perfused were quantified using Image J software. RESULTS: We found that the primary type of mucous of the epithelial and submucosal mucous cells was AB-positive and PAS-positive, respectively. Acid exposure of either esophageal segment caused a greater total and PAS-positive mucous content of the submucosal cells adjacent to the HCl-administered esophagus than adjacent to the PBS-administered esophagus (Table). CONCLUSIONS: The primary types of mucosubstances of the tracheal epithelial and submucosal cells are acidic and neutral respectively. Esophageal acid exposure increases mucus production of neutral mucosubstances of the tracheal submucosa probably through the previously identified local direct neural connection between the esophagus and trachea. We hypothesize that this pathway is part of the innate tracheal defense mechanism which prepares the trachea for acid exposure due to gastric reflux. Effects of HCl and PBS on Tracheal Mucous Content

Tu1765 Regurgitation Can Indicate Either True Esophago-Pharyngeal Reflux (EPR) Event or Upper Esophageal Sphincter (UES) and Sub-Sphincter Proximal Esophageal Acid Exposure

In prior studies we found that esophageal acid exposure caused a small decrease in airway diameter, an increase in tracheobronchial mucus secretion, and a decrease in mucociliary transport rate. However, the store of mucus is not large and can easily be depleted, therefore, we hypothesized that mucus production may be under physiological control. AIM: To determine whether a physiological stimulus can affect mucus production and to investigate the mechanism of this effect. METHODS: Sixteen cats were anesthetized using alphachloralose. The esophagus was ligated 3-4 cm from the UES and the esophagus proximal and distal to the ligation was cannulated. Either the proximal (N=8) or distal (N=8) esophagus was perfused using 0.1N HCl for 30 min followed by 30 min of PBS while the opposite esophageal segment was perfused with PBS for 60 min. The trachea was excised, fixed, sliced at 5μ, and stained with Periodic Acid Schiff (PAS)-Alcian Blue (AB) at pH 1.0. The areas of neutral (PAS-positive) and acidic (AB-positive) mucosubstances in the epithelial and submucosal mucous glands of the trachea adjacent to the proximal and distal cervical segments of esophagus perfused were quantified using Image J software. RESULTS: We found that the primary type of mucous of the epithelial and submucosal mucous cells was AB-positive and PAS-positive, respectively. Acid exposure of either esophageal segment caused a greater total and PAS-positive mucous content of the submucosal cells adjacent to the HCl-administered esophagus than adjacent to the PBS-administered esophagus (Table). CONCLUSIONS: The primary types of mucosubstances of the tracheal epithelial and submucosal cells are acidic and neutral respectively. Esophageal acid exposure increases mucus production of neutral mucosubstances of the tracheal submucosa probably through the previously identified local direct neural connection between the esophagus and trachea. We hypothesize that this pathway is part of the innate tracheal defense mechanism which prepares the trachea for acid exposure due to gastric reflux. Effects of HCl and PBS on Tracheal Mucous Content

Monotypic gland-cell regions on the body surface of two species of Arion: ultrastructure and lectin-binding properties

Distinct areas of the body surface of Arion (Arion) rufus (Linnaeus, 1758) and A. (A.) vulgaris Moquin-Tandon, 1855 contain only one type of glandular cell. The specific monotypic glandular cells that are characteristic for each of these areas differ with respect to staining properties, the structure of glycans (binding of different lectins) and in their ultrastructure, particularly in the appearance of the endoplasmic reticulum. Four such glandular areas can be defined. (1) The protein gland of the anterior margin of the foot probably produces the proteins responsible for changing the trail mucus produced from other glands to strong glue-mucus. Histochemical reactions point to the presence of neutral mucosubstances, probably mucoproteins. The strongest binding of applied lectins were those specific for N-acetyl-α-d-galactosaminyl residues, specific for β-linked terminal galactose, and specific for galactose β1-3N-acetylgalactosamine. A characteristic feature of the ultrastructure of the gland cells is tightly arranged membranes of the endoplasmic reticulum as typically found in protein secreting cells. (2) The suprapedal gland consists of a flat anterior part (located in the bottom of a funnel-shaped cavity between the ventral surface of the head and the opposite dorsal surface of the anterior foot) and a posterior tubular part on the dorsal side of the foot musculature (opening by an excretory duct into the funnel-shaped cavity). Histochemical reactions indicate the presence of acid glycosaminoglycans of high negative charge density. Binding of lectins with all secretion stages indicate the presence of the terminal sequence Galα-1-3Galβ1-R. As a special feature of the ultrastructure of the gland cells, their endoplasmic reticulum contains densely packed tubules protruding at right angle from its membrane into its lumen. (3) On the ventral surface of the head, a monotypic glandular region extends into the roof of the funnel-shaped recess. Histochemical reactions indicate the presence of neutral mucosubstances. The strongest bindings of the applied lectins with the secretion were specific for N-acetyl-α-d-galactosaminyl residues and for β-linked terminal galactose. (4) Another monotypic glandular region is situated in the ventral surface of the anterior part of the mantle. Histochemical reactions indicate acid mucosubstances with high negative charge density. None of the applied lectins reacted with cells of that region. Each of the first three glandular regions has an extension into the peripodial groove on either side of the foot sole; the ‘peripodial gland’ of authors is therefore a compound structure. The branches of the protein gland extend as far back as the level of the pneumostome, while the branches of the suprapedal gland and of the glandular region of the ventral surface of the head extend further, to the corners of the base of the triangular caudal gland. The trail mucus is produced mainly by the suprapedal gland that extends with its branches into the peripodial groove. Monotypic gland cell regions are possible candidates as sources of mucus of known cellular origin for biochemical analyses.

Biomaterial scaffolds in cartilage–subchondral bone defects influencing the repair of autologous articular cartilage transplants

The repair of articular cartilage typically involves the repair of cartilage-subchondral bone tissue defects. Although various bioactive materials have been used to repair bone defects, how these bioactive materials in subchondral bone defects influence the repair of autologous cartilage transplant remains unclear. The aim of this study was to investigate the effects of different subchondral biomaterial scaffolds on the repair of autologous cartilage transplant in a sheep model. Cylindrical cartilage-subchondral bone defects were created in the right femoral knee joint of each sheep. The subchondral bone defects were implanted with hydroxyapatite-β-tricalcium phosphate (HA-TCP), poly lactic-glycolic acid (PLGA)-HA-TCP dual-layered composite scaffolds (PLGA/HA-TCP scaffolds), or autologous bone chips. The autologous cartilage layer was placed on top of the subchondral materials. After 3 months, the effect of different subchondral scaffolds on the repair of autologous cartilage transplant was systematically studied by investigating the mechanical strength, structural integration, and histological responses. The results showed that the transplanted cartilage layer supported by HA-TCP scaffolds had better structural integration and higher mechanical strength than that supported by PLGA/HA-TCP scaffolds. Furthermore, HA-TCP-supported cartilage showed higher expression of acid mucosubstances and glycol-amino-glycan contents than that supported by PLGA/HA-TCP scaffolds. Our results suggested that the physicochemical properties, including the inherent mechanical strength and material chemistry of the scaffolds, play important roles in influencing the repair of autologous cartilage transplants. The study may provide useful information for the design and selection of proper subchondral biomaterials to support the repair of both subchondral bone and cartilage defects.

Structural diversity of nuptial pads in Phyllomedusinae (Amphibia: Anura: Hylidae)

We studied the morphological variation of the nuptial pads using light microscopy and scanning electron microscopy (SEM) in 26 species of phyllomedusines (Anura: Hylidae), representing the five currently recognized genera. All phyllomedusines have single nuptial pads with dark colored epidermal projections (EPs). Spine-shaped EPs occur in Cruziohyla calcarifer, Phrynomedusa appendiculata and in one species of Phasmahyla. The other species have roundish EPs. The density of the EPs on the pad is variable. Species in the Phyllomedusa hypochondrialis Group have EPs with a density that varies between 764 ± 58/mm(2) and 923 ± 160/mm(2). In all other studied species (including the Phyllomedusa burmeisteri and Phyllomedusa perinesos groups, Phyllomedusa camba, Phyllomedusa boliviana, Phyllomedusa sauvagii, Phyllomedusa bicolor, and Phyllomedusa tomopterna) the density of EPs varies between 108 ± 20/mm(2) and 552 ± 97/mm(2). Pores were observed with SEM in C. calcarifer, Agalychnis lemur, Agalychnis moreletii, but its presence is confirmed through histological sections on several other species. Its visibility using SEM seems to be related with the level of separation between adjacent EPs. The pores in the four studied species of Agalychnis are shown with SEM and histological sections to have a characteristic epidermal rim, that is absent in the otherphyllomedusines. Unlike most previous reports on breeding glands, those of phyllomedusines are alcian blue positive, indicating the presence of acidic mucosubstances on its secretions.

Subchronic exposure to atrazine induces biochemical and histopathological changes in the gills of a Neotropical freshwater fish, Prochilodus lineatus

The impact of acute (48h) and subchronic (14 days) exposures to environmentally realistic atrazine concentrations (2, 10 and 25μgL−1) were evaluated on the gills of Prochilodus lineatus by assessing the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), the levels of reduced glutathione (GSH) and lipid peroxide (LPO) as well as the histopathological damage. Acute and subchronic exposure to atrazine at 2 or 25μgL−1 did not change the activities of GST, SOD, CAT or GPx or the concentrations of GSH and LPO; however, subchronic exposure to 10μgL−1 increased the activity of GST, SOD and CAT and the LPO level. Histopathological indexes indicated normal gill function with scattered epithelial changes after acute and chronic exposure to 2 or 10μgL−1 of atrazine; however, fish chronically exposed to 25μgL−1 of atrazine, although had scattered lesions, the severity of lesions resulted in slightly to moderately gill damage. Acute exposure to atrazine decreased the type 3 MCs (containing acid mucosubstances with sulfate esters) in fish exposed to 2 or 10μgL−1 and increased the type 4 MCs (containing all types of mucosubstances) in fish exposed to 25μgL−1. Chronic exposure to atrazine reduced the type 3 MCs in fish exposed to 10 or 25μgL−1. The gills showed a low sensitivity to atrazine after acute exposure. However, the persistence of atrazine in water (subchronic exposure) promoted an increase of LPO levels in the gills and increased the frequency and severity of histopathological changes. The decreased density of type 3 MCs in fish exposed to atrazine suggests a mechanism to wash toxic substances away from the gill surface.

Epileptic activity in neuronal cells, induced by mercuric chloride and cadmium chloride in terrestrial slug Semperula maculata: fine structure investigated by histology and histochemistry

Although the central nervous system (CNS) of gastropods has been used as a model for studying neurocommunications and related immunohistochemical studies, there is scanty information on histochemical alterations in neuronal cells due to metal pollution. This study was designed to investigate neuronal alterations in cerebral ganglia intoxicated with mercuric chloride (HgCl2) and cadmium chloride (CdCl2)in terrestrial gastropods slug S. maculata. Histochemically acidic and neutral mucosubstances of neuronal cells were found directly proportional to exposure duration. The glycogen moiety in the neuronal cells was significantly decreased. Hyperplasia was found to be significant in neuronal cell with increased nuclear diameter. Histomorphological and neurochemical alterations were more prominent following HgCl2 than CdCl2 intoxication.