Showing papers on "Apical cytoplasm published in 1981"

Immunocytochemical Localization of Androgen-Binding Protein in the Male Rat Reproductive Tract*

Abstract: The localization of androgen-binding protein (ABP) in the reproductive tract of young adult male rats was studied with the peroxidase-antiperoxidase technique using frozen sections and light microscopy. Within the seminiferous tubules, a positive reaction was noted in the apical portion of the epithelium, apparently in spermatids and/or Sertoli cells. ABP was localized in granules in the apical cytoplasm of the principal epithelial cells of the proximal part of the caput epididymis and in the epithelial cells of the ductuli efferentes. The cells in the distal part of the caput as well as the corpus and cauda of the epididymis did not contain ABP. Numerous coated vesicles and multivesicular bodies were present in the supranuclear cytoplasm of the epididymal epithelium where ABP was taken up. The results indicate that ABP is taken up from the lumen by epithelial cells of the ductuli efferentes and proximal part of the caput epididymis.

Transport across endodermal cells of the chick yolk sac during early stages of development.

Abstract: The endoderm of the chick yolk sac mediates the transfer of materials from the yolk mass to the embryonic circulation. There is little evidence of endocytotic activity in the area pellucida, but the endodermal cells of the area vasculosa possess many microvilli and bristle-coated pits and vesicles, as well as a canalicular system and vacuoles in the apical cytoplasm. Three tracers, horseradish peroxidase, ferritin, and latex spheres, were injected beneath the endoderm of both cultured embryos and embryos in ovo to study the pathway of uptake of extracellular materials. All tracers were sequestered in bristle-coated pits (200–500 nm in diameter) of the endodermal cells of the area vasculosa, but not those of the area pellucida. Both horseradish peroxidase and latex spheres (and probably ferritin) were incorporated into pleomorphic intracellular yolk drops through bristle-coated pits and vesicles, and then into apical vacuoles, which fuse with the intracellular yolk drops. Horseradish peroxidase and ferritin were also found within apical canaliculi. The apical junctions between endodermal cells prevented the intercellular passage of the tracers. A ‘topping-up’ hypothesis is proposed whereby endodermal cells of the area vasculosa continually sequester extracellular yolk material, which is incorporated into a digesting intracellular yolk drop while, at the same time, digested yolk products are being transported across the vascular pole of the endoderm to the extraembryonic circulation and thence to the embryo.

The epithelium covering Peyer's patches in young milk-fed calves. An ultrastructural and enzyme histochemical investigation.

Abstract: Between the ordinary villi over Peyer’s patches there are small domes or “pseudovilli” caused by bulges in the lymphoid tissue. These “pseudovilli” were studied in 5 healthy milk-fed, about 3-week-old, pre-ruminant calves. Scanning electron microscopy revealed that the “pseudovilli” were covered by a specialized follicle associated epithelium (FAE). The FAE had poorly developed microvilli and often extensive folding of the cell surface close to the cell borders. By transmission electron microscopy the tips of the marginal folds of the FAE seemed to fuse, probably in the process of enfolding bulk material from the lumen. The FAE apical cytoplasm contained numerous thick-walled and bristle-coated invaginations, tubules and vesicles indicative of micropinocytosis. Multivesicular bodies and large vacuoles were frequent. Indications of extracellular unloading of residual bodies were found. Intraepithelial lymphocytes tended to group together, and some were rich in rough endoplasmic reticulum. Enzyme histochemistry showed weak reactions of adenosine triphosphate splitting enzyme and aminopeptidase in the FAE luminal cell border. Cytoplasmic acid phosrphatase showed a marked basal-apical decrease along the “pseudovillus” probably caused by the onset of endocytosis. The results of this study appear compatible with the concept that the FAE takes up macromolecules from the lumen by pinocytosis and sensitizes lymphocytes.

A morphological and biochemical study of the effects of L-cysteine on the renal uptake and nephrotoxicity of cadmium.

Abstract: In JCLR and Wistar-Porton rats renal concentrations of Cd2+ were maximal (21-22 micrograms Cd2+/g wet wt tissue) at 1 and 4 h respectively after the administration of CdCl2 (10 micromol, 1-12 mg Cd2+/kg body wt) together with L-cysteine (5 mmol/kg body wt). Synthesis of metallothionein in the kidney in response to the uptake of Cd2+, which occurred between 2 and 7 h after treatment in the Wistar-Porton rat, affected the distribution of Cd2+ between proteins of the renal soluble fraction, but not between the particulate components and, at both times, about 40% of the total Cd2+ was associated with the heterogeneous nuclei + cell debris fraction. Autoradiographic studies with 109CdCl2 revealed that Cd2+, accumulated by the kidney under these conditions, was not uniformly distributed throughout the renal cortex, but was concentrated unevenly in proximal tubules in the outer stripe of the outer zone of the medulla. Pathological changes, which were correlated with the concentrations of accumulated Cd2+ and were limited to the S3 segments of the proximal tubules, were apparent by light microscopy at 4 h after the administration of Cd2+ + cysteine and progressed with time. Thus by 7 h the lesion had extended to include almost the whole of the outer stripe of the outer zone of the medulla and, by 24 h the cells of the affected epithelia showed extensive necrosis and karyorrhexis. At this, as at earlier times, the cortex appeared to be undamaged. Neither these nor other morphological changes were observed in the kidneys of animals that had been dosed with either Cd2+, or L-cysteine alone. Within 60 min of the administration of Cd2+ + cysteine an increase in the number of endocytotic vesicles in the apical cytoplasm of the proximal tubular epithelium was observed by electron microscopy. Subsequent cytoplasmic vesiculation, which was conspicuous at 2 h, was extensive and widespread in both the apical and basal regions of the cytoplasm at 4 h. In some cells at this time the nuclei were irregular in shape; the mitochondria were swollen and their cristae were disorganized. As, after the administration of either Cd2+ or cadmium-metallothionein, damage is known to occur in the S1 and S2 segments of proximal tubules throughout the cortex, the Cd2+ + cysteine combination does not provide an exact model which reproduces in a short time the effects of long-term, low level exposure to Cd2+. Nevertheless it is suggested that the toxic mechanisms are the same after either treatment with Cd2+ + cysteine or continual exposure to Cd2+, but are limited to different segments of the proximal tubules. Possible mechanisms of toxicity are discussed.

Ultrastructural markers of colonic adenocarcinoma.

Abstract: A mixed population of 96 adenocarcinomas was examined by electron microscopy to establish the presence of organ specific features. This resulted in the identification of fine structural characteristics, occurring consistently in colorectal adenocarcinomas but not in other epithelial tumors. The colorectal "ultrastructural profile" consists of microvilli with dense cores of microfilaments extending as long rootlets into a clear zone of apical cytoplasm, apical electron dense bodies, and abundant glycocalyceal bodies. Of these features, the long rootlets constitute the best morphologic marker for large intestinal type adenocarcinoma. Using these characteristics in another series of 58 adenocarcinomas studied in a double-blind manner, it was possible to distinguish colorectal adenocarcinomas from other carcinomas on ultrastructural grounds alone.

The epithelium of the excretory duct of the human submandibular gland: a transmission and scanning electron microscopic study.

Abstract: The duct of the human submandibular gland (Wharton) is lined by a pseudostratified epithelium consisting of principal and basal cells. Scattered among them are a few goblet and ciliated cells. The principal cells are columnar in shape with many mitochondria, numerous dense bodies and a central nucleus with some indentations. Their apical cytoplasm shows a number of clear vesicles, some of which are reactive to silver and are extruded by exocytosis into the lumen. Other vesicles, which are unreactive, may represent the products of the absorption process. A mechanism of apocrine secretion is also observed in the principal cells. Thus, with regard to its functions, the duct of the human submandibular gland modifies the composition of saliva by adding a secretory component to it. This latter material is derived from the goblet cells but chiefly from merocrine (exocytosis) and apocrine secretion of principal cells.

Intracellular transport and secretion of fibroin in the posterior silk gland of the silkworm Bombyx mori.

Abstract: Intracellular transport and secretion of fibroin in the posterior silk gland cells of the silkworm, Bombyx mori, were investigated in relation to the radial microtubule and circular microtubule-microfilament systems of the cells. The silk glands were pulse-labelled for 3 min with [3H]glycine in vitro and then chased in media containing excess cold glycine and in some cases antimitotic reagents (colchicine or vinblastine) or cytochalasin (B or D), and the flow of the label in the glands was investigated by radioautography. It was revealed that the label initially located over the rough endoplasmic reticulum subsequently moves to the Golgi bodies to be condensed there. The secretory granules of fibroin or fibroin globules thus formed are transported via the radial microtubule system to the apical cytoplasm to be secreted there under some regulation by the circular microtubule-microfilament system. In the presence of colchicine or vinblastine, the secretion of fibroin was suppressed an marked accumulation of fibroin globules in the Golgi regions was observed, while in the presence of cytochalasin B or D the secretion was accelerated and extensive invagination of the luminal surface, which was probably due to the serial exocytosis of fibroin globules, was observed. These results suggest that the radial microtubule system and the circular microtubule-microfilament system are responsible for intracellular transport of fibroin globules from Golgi bodies to the apical cytoplasm and secretion by exocytosis at the luminal surface, respectively.

Ultrastructural studies on the secretory mechanism of goblet cells in the rat jejunal epithelium.

Abstract: Goblet cells in the jejunal epithelium of adult and suckling rats were studied with transmission electron microscope. The use of triple fixation, i.e., osmium-aldehyde-osmium has some advantages in the preservation of mucous substances and some cell organelles. Cytochemical demonstration of polysaccharide and glycoprotein by methenamine silver as well as detection of TPPase and acid phosphatase (AcPase) were performed. Accumulation of secretory substances and combination with sugar moieties occurred in the internal sacs of Golgi lamellae, where TPPase activity was recognized. No rigid lamella usually positive to AcPase was found in goblet cells, though it was easily found in the columnar absorptive cells. AcPase was positive in some small immature mucus droplets as well as lysosomes.As the differentiation of goblet cells advances, mucus droplets come into contact and fuse to each other. As a result of the close contact of two adjacent membranes of mucus droplets, a pentalaminar structure is first formed. Then the central dense lamina disappears and the membrane becomes trilaminar. Disappearance of one of the apposed unit membranes, leaving another unit membrane, may take place. Finally the single unit membrane left between the adjacent droplets is also ruptured and complete fusion occurs.The mechanism of extrusion of mucous substance is complicated. Some mucus droplets located at the most superficial area may be released by the mechanism of exocytosis. More frequently, however, deeply located droplets fuse to each other and a huge vacuole is made in the apical cytoplasm. The substance filling the vacuole contains debris of cytoplasmic matrix and droplet membranes along with mucous secretory substance. These substances derived from different sources are expelled into the lumen at the same time. This may be classified into the apocrine mechanism, because a part of the cytoplasm and membranes are lost. The typical apocrine secretion, i. e., pinching off of cytoplasmic projection containing mucus droplets, was also found in the goblet cells. Thus, two or three different mechanisms of secretion discharge may possibly occur simultaneously in goblet cells.

Membrane specialization in the rat epididymis. II. The clear cell.

Abstract: The clear cell is a characteristic cell type, particularly frequent in the epididymal tail, which has many small vesicles and larger vacuoles in the apical cytoplasm. In freeze-fracture replicas of adult rat epididymis, we found that the limiting membrane (P-face) of these vesicles and vacuoles, as well as the luminal plasma membrane (but not the basolateral membrane) contain a high density of prominent intramembrane particles. In contrast, the apical vesicles of the most common cell type, the principal cell, have a much lower density of particles, which are also of smaller size. The unique organization of these membranes in clear cells suggests that this cell type has a special role in epididymal function.

Developmental changes in the fine structure of the chorion laeve (smooth chorion) of the rhesus monkey placenta.

Abstract: Developmental changes in the fine structure of the chorion laeve (smooth chorion) of the rhesus monkey were studied at two time periods during gestation: 1) Early (19-60 days of gestation), before the chorionic epithelium fuses with the parietal decidua, and 2) near term, when the fused chorioamnion has also fused with the parietal decidua. Early in gestation the chorionic epithelium consisted of columnar and cuboidal cells one or two layers thick. The apical border of the cells had microvilli and coated pits, and adjacent cells were joined by tight junctions and desmosomes. The chorionic epithelial cells during this early period contained numerous large vesicles and vacuoles of varying electron-density. The apical cytoplasm contained various small coated vesicles and tubules. Taken together these observations were interpreted as indicating a possible role for these cells in endocytosis or phagocytosis of substances from the uterine lumen; i.e., a potential role in histiotrophic nutrition during this early period. Late in gestation the trophoblastic cells were more irregular in shape. The cells contained abundant granular endoplasmic reticulum (ER) and mitochondria, and a well-developed Golgi complex, suggesting the cells were actively synthetic late in gestation. The numerous cytoplasmic vacuoles characteristic of the trophoblastic cells of early gestation were absent near term. Glycogen deposits and lipid droplets were moderately well-developed near term. Most of the cells were joined by desmosomes but wide intercellular spaces, unobstructed by any cell junctions, were frequently observed. This observation provides at least one explanation for the increase in permeability of the chorion laeve later in gestation. Cells of the parietal decidua associated with the chorion laeve were also examined. These cells generally had a well-developed granular ER and Golgi apparatus, and numerous mitochondria. Limited numbers of membrane-bounded secretory bodies, similar to those in human decidual cells, were also present.

An Electron Microscopic Study of the Kitten Liver with Special Reference to Fat-Storing Cells

Abstract: In a 67-day -old female kitten, the morphological differentiation of the hepatic parenchyma has been electron microscopically examined. 1)In spite of the advanced ultrastructural differentiation of the hepatocyte, the usual location of the Golgi complex to the apical cytoplasm around the bile canaliculus has not yet been established. Numerous mitochondria are mingled with round microbodies characterized by a marginal plate and a crystalloid core. Tubular cisternae of the SER occur only around the microbodies and lack within the accumulation of glycogen alpha-particles. 2)The sinusoidal lining has been fully differentiated and is composed of the "cytoplasmic processes" and the "sieve plates" whose fenestrae average 13300 A in diameter. 3) Kupffer cell shows an active phagocytosis to blood cells. The fuzzy coat is unsatisfactorily preserved. The cytoplasm occasionally shows short segments of a worm-like body. 4) The fat-storing cell (FSC) contains a small amount of lipid droplets which mostly appear within the dense accumulation of glycogen beta-particles. Also empty FSCs devoid of lipid droplets mostly possess glycogen accumulations. The glycogen accumulations enclosing lipid droplets are closely juxtaposed by cisternae of the RER and mitochondria, suggesting the possible involvement of these organelles as well as glycogen in the lipid synthesis in the FSC. In most FSCs, abundant cisternae of the RER are dilated and filled up with a finely flocculent material, suggesting an active production of collagen precursor. The FSCs possess abundant microfilaments and microtubules. A single cilium is issued into the Disse's space from one of the paired centrioles located in the Golgi area. 5) The Disse's space of the kitten contains, besides FSCs, plasma cells and macrophages. The latter agree in ultrastructure with the Kupffer cells and are assumed to be transformed into them by being incorporated in the endothelial lining of the sinusoid.

The fine structure of the gastric epithelium of the rainbow trout, Salmo gairdneri, Richardson

Abstract: Fine structural characteristics of the columnar mucus cells lining the surface and pits of the gastric mucosa, oxyntic cells lining the glands and the gastric endocrine cells were studied. The surface mucus cells, in addition to their primary involvement in production of mucus, showed structural adaptations. Release of the mucus vesicles was achieved by exocytosis. Transition from pit gland cells was abrupt since no mucus neck cells were observed. The oxyntic cells possessed apical and basal microvillous processes, a well developed tubulovesicular system, zymogen granules and extensive RER associated with many large mitochondria. When stimulated by distension of the stomach, the apical cytoplasm was converted into a labyrinth of cytoplasmic processes, while annular lamellae, each of which showed a short peripheral linear density appeared in the basal cytoplasm. The endocrine cells showed apical modifications as microvilli, cilia and reduced glycocalyx covering. Three types were distinguished on the basis of their granular morphology.

Fine structural and functional study of the prostatic complex of the guinea pig.

Abstract: The fine structure of the prostate gland of the guinea pig was studied by electron microscopy. The lateral lobe was characterized by tall columnar epithelium which formed various degrees of foldings. The epithelial cells had well developed granular endoplasmic reticulum (GER). The cisternae were closely packed and often arranged in concentric configuration in the basal cytoplasm. The apical cytoplasm was characterized by a large Golgi and prominent secretory granules. The luminal border typically contained microvilli. Fusion of the secretory granules with the luminal membrane were observed. The secretion in this lobe is believed to be triggered by a merocrine mechanism. The glandular cells of the dorsal prostate were characterized by well-developed and dilated GER. Most cells had no secretory granules and the luminal surface was endowed with microvilli. It is believed that in these cells the secretion is stored in the cisternae and may be discharged directly into the lumen. A small number of cells in the dorsal prostate showed large dense secretory granules in the apical region. Secretion in this group of cells, as in the cells of the lateral prostate, is believed to be produced by a merocrine mechanism. The coagulating gland on the other hand, had sparser GER and less dilated cisternae. The cells contained no secretory granules and usually had a small Golgi. Apical blebs were commonly found in these cells. Apical blebs have been observed to pinch off from the apical cytoplasm and to release the small sacs of secretory material into the lumen. This is an apocrine mechanism of secretion.

"In situ"--measurements of protein contents in the brush border region along rat jejunal villi and their correlations with four enzyme activities.

Abstract: In order to quantify the amount of protein in the small intestinal brush border region at different villus sites, cryostat sections of adult rat jejunum were stained with Naphthol Yellow S, Dinitrofluorobenzene and Coomassie Brilliant Blue and the dye deposits were evaluated cytophotometrically. Judged by the absorbance spectra in the tissue sections and the increase in absorbance as a function of the optical pathway (section thickness), Naphthol Yellow S proved to be the most suitable quantitative protein stain. By continuously measuring the absorbance of this dye at λ 440 nm rectangular to the villus in the longitudinal axis of the enterocytes, a peak was registered in the brush border region which clearly could be differentiated from the apical cytoplasm. The amount of protein in the brush border region was determined at six different positions equally distributed along the villus. In parallel four brush border enzymes (neutral α-and β-glucosidase, unspecific alkaline phosphatase and dipeptidylpeptidase IV) were quantified by the same measuring technique in the Vmax-range of their substrate hydrolysis at equivalent villus positions. Their activities were correlated to the amount of protein. The absorbance data both for protein and for enzyme activities were significantly influenced by the villus position. They revealed an increasing gradient from the basal to the apical villus. In an additional analysis of the breadth of the dye deposits at the different measuring positions on the villus, it was shown that this parameter also ran parallel with the absorbance values.

Morphological and histochemical observations on the duodenal glands of eight wild ungulate species native to North America.

Abstract: The duodenal glands of the species examined (Alces alces, Ovis canadensis, Cervus canadensis, Oreamnos americanus, Bison bison, Antilocapra americana, Odocoileus virginianas, Odocoileus heminous) are confined primarily to the submucosa of the small intestine. In one species, the moose, a significant population of secretory tubules also is observed in the mucosa. The ducts of the duodenal glands pierce the overlying muscularis mucosae to empty most often independently into the intestinal lumen. Those of the bison, unlike the other species examined, drain into intestinal glands. The duodenal glands consist primarily of a simple columnar epithelium, the cells of which contain basally positioned round or oval nuclei. The lumina of scattered duodenal glands in the pronghorn and to some extent those of the moose, white-tailed deer, and mule deer may be extremely dilated, and the surrounding epithelium thin and attenuated. Component cells of the duodenal glands of all the species examined show remarkably similar ultrastructural features. They exhibit scattered profiles of rough endoplasmic reticulum, dilated cisternae of which contain an electron-dense, amorphous material. Numerous well-developed Golgi complexes occupy the supranuclear region together with transport vesicles and forming secretory granules. Electron-dense, membrane-bound secretory granules generally are concentrated in the apical cytoplasm immediately subjacent to the cell membrane. The apical cell membrane exhibits short, scattered microvilli; and the basal cell membrane is smooth without apparent specialization. Histochemically, the duodenal glands of most species examined in this study consist of a heterogeneous population. The majority of the glands of the moose, elk, mountain goat, bison, pronghorn, and white-tailed deer elaborate a neutral mucin, whereas scattered individual glands, tubules or cells also produce acid mucins. Cells near the terminations of the ducts of the bighorn sheep are the only elements to produce acid mucins in the duodenal glands of this species. The duodenal glands of the bison are unusual in that only the peripheral portions of individual glands produce acid mucins. The remainder of the glands elaborate neutral mucins. Morphological differences between the two regions were not observed. The duodenal glands of the mule deer secrete both acid and neutral mucins. The structural and histochemical observations appear unrelated to the diet of individual species.

Absorption of protein molecules by the small intestine of the bullfrog tadpole, Rana catesbeiana

Abstract: In the tadpole of the bullfrog, Rana catesbeiana, the absorptive cells of the small intestine are characterized by the presence of invaginations of the surface plasma membrane or pinocytic vesicles in the apical cytoplasm and numerous lysosomes in the supranuclear region. These cytological features suggest that the absorptive cells may be able to ingest some macromolecules or particles. The possibility of macromolecular absorption in this animal was examined by using horseradish peroxidase (HRP) and the electron microscopic cytochemical technique. Exogenous HRP was ingested in the absorptive cells by pinocytosis and then accumulated in multivesicular bodies (MVBs) by the contribution of pinocytic vesicles to MVBs. The pinocytic vesicle changed its shape to have an inner vesicle. Some of the inner vesicles of MVBs seem to have originated from the inner vesicles of pinocytic vesicles. Almost all the MVBs in the subapical region showed HRP activity, but some of them showed no acid phosphatase (AcPase) activity; those in the supranuclear region always showed an intense AcPase activity. Therefore some of the subapical MVBs are heterophagosomes and may be joined with lysosome during the movement toward the supranuclear region. The MVBs with lysosomal enzymes in the subapical or supranuclear region are presumably important sites of intracellular digestion. The results indicate that intracellular digestion may occur in the small intestine of the bullfrog tadpole under natural conditions.

Fine structure and FSH binding of Sertoli cells in the blue fox (Alopex lagopus) in different stages of reproductive activity.

Abstract: A clearly different Sertoli cell morphology was found in the immature blue fox and in the adults in and out of season. Immature cells had small, basally, located nuclei rich in peripheral heterochromatin, and few cytoplasmic organelles. Sertoli cells from adults in season had basally located, large, convoluted nuclei with homogenous nucleoplasma and prominent nucleoli. The basal and intermediate parts of the cytoplasm contained an extensively developed ER, numerous mitochondria, free ribosomes, lipid droplets and residual bodies, while the apical cytoplasm showed few distinct structures. In Sertoii cells from adults out of season the nuclei were dislocated towards the lumen, and apart from numerous dilated cisternae of ER, there were generally fewer organelles, but more glycogen particles. A marked rise in FSH binding was found towards the breeding season.

Light- and electron-microscopic radioautographic study of glycoprotein secretion in the granular duct of the submandibular gland of the male mouse.

Abstract: L-3H-fucose was injected intravenously into adult male mice, after which, at different time intervals, the submandibular glands were removed and processed for light-and electron-microscopic radioautography. This radio active hexose was taken up by newly synthesized glycoproteins in the cells lining the granular ducts which were maximally labeled at 4 h after injection. Between 4 and 72 h the amount of labeled glycoproteins decreased moderately indicating that these macromolecules undergo a slow renewal. The main subcellular site of incorporation of 3 H-fucose into glycoproteins was the Golgi apparatus. From this organelle labeled glycoproteins were transferred to small secretory granules (diameter up to 1.0 μm) located not only near the Golgi region but also throughout the apical cytoplasm. At 1 h after injection the concentration of label reached a maximum in the small secretory granules and labeling of medium (diameter between 1.1 and 2.0 μm) and large (diameter over 2.0 μm) granules was very low. At this postinjection interval the secretion product inside the lumen of the duct was already labeled. Between 1 and 72 h after injection the concentration of radioactivity in the small secretory granules decreased intensely while increasing in the medium and in the large ones. The concentration of fucose label reached a maximum in the medium secretory granules at 24 h and in the large ones at 72 h after injection. Additional experiments using mice previously injected with 4 intraperitoneal doses of 3H-fucose given 3 h apart demonstrated that the large granules undergo a very slow renewal. Some were found to be labeled as long as 28 days after administration of 3H-fucose. Recorded in this latter series of experiments was the labeling pattern of dense bodies that were regularly visualized in the cells lining the granular ducts. Their significance in the secretory process is discussed. In conclusion, newly synthesized glycoproteins are transferred from the Golgi apparatus to small secretory granules which carry a readily releasible pool of these macromolecules to the lumen of the duct. The small secretory granules also transfer newly synthesized glycoproteins to medium and large secretion granules which store a pool that is released very slowly. This characterizes the large secretory granules as the intracellular sites of storage of secretion products. The results of this investigation were correlated with the knowledge about the chemical composition of the different macromolecules that are known to be synthesized by the secretory cells of the granular ducts of the submandibular gland of the mouse.

Studies of the deferent ducts from the testis of the African elephant, Loxodonta africana. III. Ultrastructure and cytochemistry of the ductuli efferentes.

Abstract: The epithelium of the ductuli efferentes is composed of ciliated, principal, halo and basal cells The supranuclear cytoplasm of ciliated cells is penetrated by particularly long cilial rootlets which are surrounded by numerous elongate mitochondria Microtubules are arranged along the longitudinal axis of the cells The spaces between the microvilli of principal cells form canaliculi which penetrate the apical cytoplasm and appear to be involved in endocytotic activity The supranuclear cytoplasm contains oval mitochondria and numerous vacuoles Both ciliated and principal cells contain poorly developed Golgi and endoplasmic reticulum, but numerous supranuclear dense bodies are usually present Supranuclear and basal accumulations of dense bodies were identified as lipofuscin; they were the source of brown pigmentation in the proximal two thirds of the ductuli efferentes The halo cells were probably macrophages They occurred quite frequently and contained crescent shaped nuclei and large accumulations of lipofuscin material

Ultrastructure and Histochemistry of the Submandibular Gland of the Japanese Wood Mouse (Apodemus ainu ainu TOKUDA)

Abstract: The submandibular glands of adult female and male Japanese wood mice (Apodemus ainu ainu Tokuda) were studied histochemically using toluidine blue (pH 2.5, 4.1 and 7.0, McIlvaine), PAS reaction, Millon's reaction for tyrosine, p-dimethylaminobenzaldehyde for tryptophan, and substrate film techniques for amylase and protease. The glands were also examined ultrastructurally and ultracytochemically by the periodic acid-thiocarbohydrazide-silver proteinate technique (PA-TCH-SP staining) for glycoprotein. The submandibular gland consisted of the striated ducts (SDs), the convoluted granular tubules (CGTs), the intercalated ducts and the terminal portions. In both sexes the acinar cells were seromucous in secretory nature, and the secretory granules contained glycoproteins and were negative to amylase and protease activities. By the PA-TCH-SP staining, the distribution of glycoproteins and fine structural alternations corresponding to the maturation of the secretory granules were demonstrated. The granules of the CGT cells contained tryptophan, tyrosine and neutral mucopolysaccharides. The granules showed negative reactions to acid mucopolysaccharides, protease and amylase activities, and glycoproteins. Glycogen particles in the apocrine processes were intensely positive to PA-TCH-SP staining. Dark and clear cells were distinguished in the SDs. The apical cytoplasm of the SD cells contained two types of vesicles. One type may represent reabsorption vesicles and the other secretory vesicles. Some of the SD cells had both microvilli, associated with reabsorption vesicles and apocrine process containing abundant glycogen particles on their luminal surface. From the statistical analysis of the average values, the CGT diameter of the male mice was significantly larger than that of the female mice.

Peripheral avian yolk assemblage and its persistence in the blastoderm, studied by trypan blue-induced fluorescence.

Abstract: Shortly after subcutaneous or intraperitoneal injection of nontoxic quantities of trypan blue into laying Japanese quails, red fluorescent yolk granules appear in the peripheral ooplasm of their oocytes at the end of the lampbrush stage or subsequently. Later a red fluorescence can be observed in the apical cytoplasm of the granulosa cells. The results obtained by this method confirm our previous results (Callebaut 1974) obtained by autoradiography after 3H-leucine administration and furnish interesting additional data. The trypan blue-induced fluorescence method gives a good indication of the permeability of the oocytal cortex and its derivative the germinal disc. The avian yolk which is, or has been peripherally assembled (primordial, true white and yellow yolk) can be characteristically labelled by the administration of trypan blue. The injection of higher, still nontoxic quantities of trypan blue has a prolonged “retarding” effect and permits the marking of a broader part of the germinal disc or eventually of the blastoderm which develops from it.

Development and Maturation of the Bladder Epithelium of the Guinea Pig

Abstract: In the fetal guinea pig, transitional epithelium develops at a little beyond midterm of gestation from a single layer of columnar cells. Some of the cells elongate and overlap their neighbors, but remain attached to the basement membrane by fine cytoplasmic stalks. The fetal epithelial cells do not markedly vary in size. Within the basal layer, which is the site of mitotic activity, many cells are large and binucleate, which suggests that basal cell fusions occur. It is believed that these cells eventually become surface cells. The luminal membrane develops its asymmetric structure (asymmetric unit membrane; AUM) following the appearance of AUM-bound vesicles in the apical cytoplasm, indicating that they are the source of the luminal AUM. The vesicles originate in the Golgi cisternae and are initially cup-shaped. The immature surface cells are characterized by microvilli of varying density on the luminal surface. The characteristic mature surface ridges appear to develop from rows of microvilli which fuse and link with other rows to form a reticular pattern. The process commences shortly after mid-gestation. By –15 to -10 days, the majority of cells have a well-developed surface pattern. Microvilli, however, remain prevalent in some small surface cells. These are believed to be the younger surface cells derived from pyriform intermediate cells, with the surface not fully differentiated. During the first 3 postnatal weeks, the basal cell population reaches the adult level and mitotic activity declines. The epithelium also acquires its adult morphology, whilst its functional maturity is indicated by the adult distribution and content of both glycogen, which is reduced, and alkaline phosphatase, which is increased. Rejection of cells occurs both antenatally and postnatally, and is probably a consequence of excess cell production.

Morphological and histochemical study of the endometrial effects of Ovral in the baboon

Abstract: In an effort to better understand changes induced by hormonal contraceptives, a group of female baboons were administered Ovral for a period of 9 months. During this time the endometrium was sampled by transcervical uterine biopsy from both the treated animals and from a control group. The biopsies were all obtained between 10 and 14 days of the treatment cycle or the normal menstrual cycle. The endometrial glandular cells from the treated animals exhibited an accelerated maturation compared with the controls. Ultrastructurally this was reflected by increased cell size, numerous long, slender microvilli on the apical membranes, and increased development of the Golgi complex. Differences were also observed in the predominant type of granule seen in the apical cytoplasm. After 3 and 6 months of treatment with Ovral, no significant differences were noted between groups or between animals within a group. However, after 9 months of treatment, the endometrium displayed differences from the earlier experimental groups as well as individual variations. The functional correlates of these observations are discussed and compared to human endometrium.

Histological study of the ependyma of the hypothalamic third ventricle in the water snake Natrix maura (L).

Abstract: The ependyma of the hypothalamic third ventricle of Natrix maura (L) has been investigated by light microscopy employing Nissl and Golgi stains. Electron microscopy was also used. Brains were fixed by intraventricular perfusion and embedded in paraffin, celloidin and Spurr resin. Light-microscopically the ependyma appears as a simple layer epithelium with round or enlarged nuclei. It sometimes shows basal processes extending into the subependymal tissue. These processes can be clearly seen in Richardson stained semithin sections. They often contact the subependymal capillaries. Electronmicroscopically, tanycytes contacting capillaries show numerous microvilli and few cilia as well as pinocytotic vesicles at their apical surfaces. There are zonulae adherentes and probably gap junctions as well as digitations and desmosomes. In the apical cytoplasm there are mainly mitochondria, endoplasmic reticulum and Golgi apparatus. Near the nuclei and specially in the basal process there are many microtubules. The tanycytes contact the capillaries by an end foot containing mitochondria and pinocytotic vesicles, which are also observed in the endothelian cytoplasm. These structures lead us to think, like several other authors, that the tanycytes of Natrix maura (L) may serve as a linkage between CSF and the capillaries and that they possess the morphological features which are necessary to effect intracellular transportation.

Morphological signs of merocrine secretion in the modified Sertoli cells of the domestic fowl (Gallus domesticus).

Abstract: Testes of sexually mature White Leghorn cockerels were fixed by vascular perfusion with glutaraldehyde. Ultrastructural characteristics of the modified Sertoli cells typical of secretory activity included a large Golgi apparatus with dilated saccules, many smooth and coated vesicles, profiles of rough endoplasmic reticulum and dense granules surrounded by membranes in the Golgi area and in the basal and apical cytoplasm. Finely granulated dense bodies and some pinocytotic invaginations from the basal and lateral plasma membranes were also observed.