Distribution of epithelia in the nasal cavity of piglets

The epithelial distribution in the nasal cavity of piglets was studied by serial transverse sections. The epithelial distribution in the nasal cavity of healthy piglets varied according to the age of the animal. The transitional epithelium, which contained goblet cells but no ciliated cells, occupied a smaller proportion of the nasal cavity in the newborn piglets than in the 4-week-old piglets. The ciliated epithelium extended more rostrally in the newborn piglets and covered the non-mineralized rostral portion of the nasal ventral concha. At 28 days of age, the rostral cartilaginous concha is overlaid by the transitional epithelium, the respiratory epithelium covering the mineralized nasal ventral concha. The variations in the epithelial distribution according to age are discussed with regard to the greater susceptibility of newborn piglets to bacterial infection.     

Distribution of trace elements within bones in nasal cavity and labyrinth in humans

Measurements of trace element concentrations within bones in nasal cavity and labyrinth have shown large variations, both with a single bone and between different bones of a same individual. Factors that influence trace element levels include: metabolic activity, environmental effects, sex, and age. Detection of characteristic X-rays has been shown to be a convenient method for the measurement of concentration profiles, micropixe for micrometer variations, and X-ray centration profiles, micropixe for micrometer variations, and X-ray fluorescence for millimeter variations.     

Distribution and enzyme histochemical characterisation of mast cells in cats

Mast cells from 15 different cat organs were examined in terms of distribution and protease activity. The number of mast cells in each site was found to vary when visualised by metachromatic staining using Alcian Blue. Enzyme histochemical analysis revealed the existence of two subtypes of mast cells. These were categorised based on protease content, i.e. whether the mast cells contained chymase or tryptase. Tryptase-positive mast cells were clearly identifiable in every organ examined, whereas chymase-containing mast cells were predominantly observed in the ear (skin), tongue, spleen, and submucosa of the stomach and rectum. The chymase-reactive cells were not detected in the heart, or in the muscularis or serosa of the duodenum, jejunum, ileum or rectum. In addition, we suggest the existence of another subtype of mast cell containing both chymase and tryptase and localised within the ear (skin), tongue, spleen and submucosa of the rectum.     

Lectin-binding pattern of neuroepithelial and respiratory epithelial cells in the mouse nasal cavity

Summary Sections from the nasal cavity of 12-day-old Swiss albino mice (NMRI strain) were subjected to lectin histochemistry. A panel of biotinylated lectins (Con A, WGA, s-WGA, PNA, SBA, DBA and UEA I) and a horseradish peroxidase-conjugated lectin (GSA II) showed marked differences in binding to the respiratory and the neuroepithelial cells. SBA (affinity for galactose andN-acetylgalactosamine), PNA (galactose) and WGA (sialic acids andN-acetylglucosamine) labelled the receptor neurons in the olfactory and vomeronasal epithelium. DBA (N-acetylgalactosamine) labelled a subgroup of about 5% of the olfactory receptor neurons, but most neurons in the vomeronasal organ. UEA I (fucose) and s-WGA (N-acetylglucosamine) intensely labelled the entire nerve cell population in the vomeronasal organ, but in the olfactory epithelium the labelling with these lectins was stratified. In the respiratory epithelium the ciliated cells were labelled with WGA and s-WGA, while the secretory cells bound most of the lectins. Thus different sugars are exposed on the surface of the different types of epithelia in the nasal cavity, providing a basis for selectivity in microbial attacks on these areas.     

Olfactory epithelium consisting of supporting cells and horizontal basal cells in the posterior nasal cavity of mice

The olfactory epithelium of mice generally consists of olfactory cells, progenitors of olfactory cells (globose basal cells), supporting cells, and horizontal basal cells. However, in the dorsal fossa (the roof) of the posterior nasal cavity of mice, we found seven epithelial patches consisting of only non-neuronal cell types, i.e., supporting cells and horizontal basal cells, among the normal olfactory epithelium. The supporting cells occupied three or four layers in the apical to middle regions; in the basal region, horizontal basal cells were localized in a single row adjacent to the basement membrane. Bowman's gland ducts were also present in the epithelium. Neuronal cells (olfactory cells and globose basal cells) were totally absent. The ultrastructure of the supporting cells, horizontal basal cells, and Bowman's glands was essentially similar to that in the normal olfactory epithelium. In the early postnatal period (P1-P7), cell types in the epithelium were the same as those in the normal olfactory epithelium. From P10 to P21, olfactory cells and globose basal cells had disappeared from the olfactory epithelium. At this period, the number of TUNEL-positive cells was significantly higher than that in the surrounding olfactory epithelium; ultrastructurally, many apoptotic figures were observed. This suggests that the epithelium consisting of supporting cells and horizontal basal cells is generated by the apoptotic death of olfactory cells and globose basal cells during postnatal development.     

Acidomucin goblet cell expansion induced by parenteral nutrition in the small intestine of piglets

Total parenteral nutrition (TPN) impairs small intestine development and is associated with barrier failure, inflammation, and acidomucin goblet cell expansion in neonatal piglets. We examined the relationship between intestinal goblet cell expansion and molecular and cellular indices of inflammation in neonatal piglets receiving TPN, 80% parenteral + 20% enteral nutrition (PEN), or 100% enteral nutrition (control) for 3 or 7 days. Epithelial permeability, T cell numbers, TNF-alpha and IFN-gamma mRNA expression, and epithelial proliferation and apoptosis were compared with goblet cell numbers over time. Epithelial permeability was similar to control in the TPN and PEN jejunum at day 3 but increased in the TPN jejunum by day 7. By day 3, intestinal T cell numbers were increased in TPN but not in PEN piglets. However, goblet cell expansion was established by day 3 in both the TPN and PEN ileum. Neither TNF-alpha nor IFN-gamma mRNA expression in the TPN and PEN ileum correlated with goblet cell expansion. Thus goblet cell expansion occurred independently of overt inflammation but in association with parenteral feeding. These data support the hypothesis that goblet cell expansion represents an initial defense triggered by reduced epithelial renewal to prevent intestinal barrier failure.     

Morphological and histochemical characterization of the seminiferous epithelial and Leydig cells of the turkey

Unlike mammals, there is little fundamental information about spermatogenesis in birds. This study was undertaken to clarify the morphology, histochemistry, and lectin affinity of the seminiferous epithelial cells and Leydig cells in pre-pubertal (8- to 15-week old) and adult (40- to 44-week old) domestic turkeys. In adult turkeys, three types of spermatogonia were defined based on their chromatin distribution and nuclear morphology: the dark type A (A(d)); the pale type A (A(p)); and the type B. The A(d) is the least numerous and least conspicuous and consequently difficult to locate. Based on its spatial distribution and overall morphology, type A(d) spermatogonia were postulated to be the spermatogonia stem cells in the turkey. Antibodies to c-kit were localized to spermatogonia in the pre-pubertal and to a lesser extent in adult males. Peanut agglutinin (PNA) was specific for spermatocytes in the pre-pubertal males and spermatogonia and early spermatocytes in adult males. Wheat-germ agglutinin (WGA) highlighted Sertoli cells in both age groups. Bandeiraea simplicifolia I, soybean agglutinin, and winged-pea agglutinin staining were limited to the wall of the seminiferous tubule and some extra-tubular cell types. Concanavalin A staining was diffuse and not cell-specific and, therefore, could not be used to selectively identify a particular cell type. It was concluded that WGA and PNA could aid in identifying specific cell types in the seminiferous epithelium of testis from pre-pubertal and mature turkeys. Only Leydig cells were alkaline phosphatase reactive in the mature turkey testes. The information from this study is being used to adapt techniques for the isolation and partial purification developed for mammalian spermatogonia to avian spermatogonia and other specific cell types in the testes.     

Subdomains of the rough endoplasmic reticulum in colon goblet cells of the rat: lectin-cytochemical characterization.

Using lectin binding, we characterized subdomains of the rough endoplasmic reticulum (rER) in goblet cells of the rat colon. In this cell type, special rER regions can be differentiated on the basis of their content of low electron density and dilated cisternal spaces in conventional transmission electron microscopic preparations. The fine fibrillar content of these cisternal regions demonstrated high-affinity binding with lectins from wheat germ, Helix pomatia, Griffonia simplicifolia I-A4 and -B4, and Ricinus communis I, although not with the sialic acid-specific Limax flavus lectin and the fucose-binding Ulex europaeus I lectin. Sugar-inhibitory experiments indicated that glycoconjugates packed within these regions bound the lectins with higher affinity than molecules present in the Golgi apparatus and secretory granules. Furthermore, the lectin binding patterns of the rER subdomains differed from those of the Golgi apparatus and mucin granules: the terminal sugar residues sialic acid and fucose were demonstrable in the Golgi apparatus and mucin granules and were absent from the rER, while galactose-recognizing lectins bound intensely at these rER regions, weakly to Golgi elements, and were almost absent from mucin granules.     

The goblet cavity matrix in the larval midgut of Hyalophora cecropia

The larval midgut of the silkmoth Hyalophora cecropia was examined using scanning electron microscopy. Goblet cells were observed to contain within their cavities a matrix plug. This matrix material was extruded onto the lumen side of the epithelium when the tissue was stretched. The rôle of this matrix material in maintenance of the capacity of the midgut to transport ions in vivo and in vitro is discussed.     

Histochemical characterization of glycoproteins present in jejunal and colonic goblet cells of pigs on different diets

Summary We examined the glycoprotein composition of intestinal goblet cells in jejunal and colonic biopsies obtained from pigs on different diets. Paraffin sections were stained both chemically and with the following horseradishperoxidase conjugated lectins: Canavalia ensiformis (Con-A), Limulus polyphemus (LPA), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), Ricinus communis (RCA1), Glycine max (SBA) and Triticum vulgaris (WGA). Using chemical staining procedures, only small quantitative differences were noted between the two organs. With respect to lectin staining, the mucus of the jejunum was characterized by the absence of Con-A binding sites, and colonic mucus consistently exhibited an absence of SBA affinity. After dietary modifications, O-acetyl sialic acid reactivity was lowered in the jejunum but was enhanced in the colon. In the jejunum, the glycoproteins became neuraminidase susceptible, whereas the colon became characterized by the absence of neutral mucins. The affinity for the tested lectins after the different diets was variable, but the most striking effects were observed after the fibreless diet (milk alone). Our data suggest the existence of marked regional variations in goblet-cell mucus and indicate significant differences between the glycoprotein components of the jejunal and colonic mucosa. Furthermore, the biosynthesis of mucins in both regions was altered by even only short-term feeding modifications.     

Temperature gradients in the nasal cavity of the rabbit

1. 1.|Temperatures at four sites along the ventral nasal concha were recorded in four unrestrained rabbits exposed to ambient temperatures from 0 to 35°C.

2. 2.|The nasal temperatures decreased and temperature gradients from proximal to distal parts of the concha increased in cold-exposed rabbits.

3. 3.|The temperature gradients increased also during panting in heat-stressed rabbits.

4. 4.|The ventral nasal concha is suggested to be an efficacious heat exchanger both in cold and hot ambient, due to its geometry and vascularization.

Distribution of goblet and endocrine cells in the intestine: A comparative study in Amazonian freshwater Tambaqui and hybrid catfish

Goblet cells (GCs) and endocrine cells (ECs) play an important role in intestine physiology, and few studies currently exist for Amazonian fishes. This study aimed to quantify the distribution of GCs and ECs producing cholecystokinin-8 and neuropeptide Y, assessed by mucin histochemistry and peptides immunohistochemistry, in the intestine of two Amazonian species with different feeding habits Tambaqui (Colossosoma macropomum) and hybrid catfish (Pseudoplatystoma reticulatum × Leiarius marmoratus), an omnivore and carnivore, respectively. A systematic literature review correlating feeding habit and GC and EC distribution was also included to contribute to the comparative study. The results of this study provided novel information about the gut cells of Tambaqui and hybrid catfish. Both, GCs and ECs can be found sweeping the entire intestine of Tambaqui and hybrid catfish although the cells can be more concentrated in certain segments. The GCs and ECs in Tambaqui were more uniformly distributed in the midgut segments (T1, T2, and T3). Unlike, in hybrid catfish GCs were more concentrated in the hindgut (C4) and ECs mainly in the two midgut segments (C1 and C2) of hybrid catfish. Based on the comparison between Tambaqui, hybrid catfish, and other fishes in the literature review, we suggest that cell distribution can be partially explained by feeding habits, carnivorous vs. omnivorous.     

Climate-related variation of the human nasal cavity

The nasal cavity is essential for humidifying and warming the air before it reaches the sensitive lungs. Because humans inhabit environments that can be seen as extreme from the perspective of respiratory function, nasal cavity shape is expected to show climatic adaptation. This study examines the relationship between modern human variation in the morphology of the nasal cavity and the climatic factors of temperature and vapor pressure, and tests the hypothesis that within increasingly demanding environments (colder and drier), nasal cavities will show features that enhance turbulence and air-wall contact to improve conditioning of the air. We use three-dimensional geometric morphometrics methods and multivariate statistics to model and analyze the shape of the bony nasal cavity of 10 modern human population samples from five climatic groups. We report significant correlations between nasal cavity shape and climatic variables of both temperature and humidity. Variation in nasal cavity shape is correlated with a cline from cold-dry climates to hot-humid climates, with a separate temperature and vapor pressure effect. The bony nasal cavity appears mostly associated with temperature, and the nasopharynx with humidity. The observed climate-related shape changes are functionally consistent with an increase in contact between air and mucosal tissue in cold-dry climates through greater turbulence during inspiration and a higher surface-to-volume ratio in the upper nasal cavity.     

Antioxidant status of the rat nasal cavity

Despite extensive interest in the rodent nasal cavity as a target organ for toxicity, there is very limited information regarding nasal defenses against oxidative stress and xenobiotic-derived oxidants. Using immunohistochemistry, we have examined the distribution of Cu,Zn and Mn superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase, and DT-diaphorase in rat nasal tissues. In addition, we have determined the concentrations of ascorbate and alpha-tocopherol and the activities of SOD (combined Cu,Zn and Mn forms), catalase, GSH peroxidase, GSH reductase, and DT-diaphorase in nasal respiratory epithelium (RE), olfactory epithelium (OE), and in lung. Immunohistochemistry demonstrated that all four enzymes were similarly distributed, with the greatest staining intensity in dorsal-medial regions of the nasal cavity. In respiratory epithelium, ciliated columnar cells and subepithelial glands stained positively, while in olfactory tissue the enzymes were detected in the sustentacular cells and Bowman's glands. With the exception of SOD, enzyme activities were higher in RE than OE, while concentrations of ascorbate and alpha-tocopherol were higher in OE than RE. With the exception of catalase, nasal activities were either higher than or comparable to those of the lung. Thus, the rat nasal cavity appears to be well protected against oxidative damage.     

Detailed flow patterns in the nasal cavity.

The human nasal cavity filters and conditions inspired air while providing olfactory function. Detailed experimental study of nasal airflow patterns has been limited because of the complex geometry of the nasal cavity. In this work, particle image velocimetry was used to determine two-dimensional instantaneous velocity vector fields in parallel planes throughout a model of the nasal cavity that was subjected to a nonoscillatory flow rate of 125 ml/s. The model, which was fabricated from 26 computed tomography scans by using rapid prototyping techniques, is a scaled replica of a human right nasal cavity. The resulting vector plots show that the flow is laminar and regions of highest velocity are in the nasal valve and in the inferior airway. The relatively low flow in the olfactory region appears to protect the olfactory bulb from particulate pollutants. Low flows were also observed in the nasal meatuses, whose primary function has been the subject of debate. Comparison of sequentially recorded data suggests a steady flow.