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PubMed1995

Sequence characteristics of a cervid DNA repeat family.

The (G + C) distribution and the presence and amounts of repetitive sequence families in the white-tailed deer (Odocoileus virginianus) have been examined. The distribution ranges from 20 to 70% (G+C) and shows four distinct repeat families. A 0.7-kb family, DII, corresponds to satellite II in domestic bovids--ox, sheep, and goat--and was singled out for detailed characterization. DII has a prototypic repeat of 67% (G + C), consists of 25,000 tandem copies, and contributes 1.7% to the genomic DNA. Sequencing and electrophoretic analysis indicate a repeat length of 691 bp. These characteristics are similar to those of the bovid satellite II families as well as to those of other cervids that we have examined. The intraspecific sequence divergence within this family has a variance of only 2.5 +/- 0.3%.

Animals↗
PubMed1981

Subendothelial fibrillar laminae in the carotid arteries of the giraffe (Giraffa camelopardalis).

The endothelium in the carotid arteries of the giraffe lies on an extensive basement membrane complex that has a distinctly fibrillar component. Small electron-dense areas occur in the basal portion of the endothelium and normally in apposition to the fibrillar laminae of the basement membrane. These zones are believed here to constitute hemi-desmosomes where endothelial attachment may be most tenacious.

Animals↗
PubMed1986

Distribution of glomerular peripolar cells in different mammalian species.

Peripolar cells are granulated glomerular epithelial cells that form a cuff around the vascular pole of the glomerulus. Quantitation of these cells in 17 species of mammals (including man, several laboratory animals and a variety of other species) indicated that they were detectable by light microscopy in all but one of the mammals that were examined (the Australian hopping mouse). In adult mammals with detectable peripolar cells, the "peripolar cell index" (the percentage of randomly sectioned glomeruli that displayed peripolar cells in histological sections of kidney) ranged from 0.15 (for echidna) to 11.86 (for sheep). Newborn lambs and rats showed strikingly high values (23.30 and 10.76, respectively) compared with their adult counterparts. Using electron microscopy, peripolar cells were observed in all species that were examined, including the Australian hopping mouse. Morphologically, peripolar cells were similar in all species although their size and granule population varied. They showed a predominantly outer cortical glomerular distribution and a close anatomical relationship with the renin-containing myo-epithelioid cells. These findings indicate that peripolar cells are present in a wide variety of species and support the view that such cells may play a significant role in the regulation of normal renal function.

Aging↗
PubMed1975

Cell number and cell density in the cerebellar cortex of man and some other mammals.

The number of cells per unit volume was determined in the cerebellar cortex of man and 19 other mammals. The cell density (i.e. the number of cells per unit volume) decreases from mammals with a low brain weight to those with a higher brain weight. This decrease in the number of cells is found to be proportional for all three layers of the cerebellar cortex. In addition, the ratio of Purkinje cells to granule cells was determined. In contrast to the decrease of all cell types with increasing brain weight, this ratio varies remarkably among the mammals and is not correlated with brain weight. In man, this ratio is 1:2991, while it is lower in all other mammals investigated. These differences in the ratio of Purkinje cells to granule cells and the decrease in cell density with increasing brain weight are discussed in relation to brain evolution.

Animals↗
PubMed1980

Qualitative and quantitative freeze-fracture studies on olfactory and nasal respiratory epithelial surfaces of frog, ox, rat, and dog. II. Cell apices, cilia, and microvilli.

The densities and diameters of intramembranous particles in olfactory and nasal respiratory structures of frog, ox, rat and dog have been compared using the freeze-fracture technique. Dendritic endings and the various segments of the cilia of the olfactory receptor cells of a given species have identical particle densities (700--1,800 particles/micrometers2 in P- and 100--600 in E-faces). Densities in P-faces of respiratory cilia are about 1/3 of those in the olfactory cilia. E-face particle densities of these respiratory cilia are often higher than P-face densities. Microvillus P-face densities range from 700--2,000 (respiratory cell microvilli) to 1,800--3,400 particles/micrometers2 (olfactory supporting and Bowman's gland microvilli). Microvillus E-faces show no conspicuous mutual differences. Literature comparisons showed that odour concentrations at threshold are considerably lower (10(5)--10(10) times) than the concentrations of olfactory receptor ending intramembranous particles (5 microM--30 microM) expressed in the same units. Relative differences in particle distributions of the various cell structures studied are usually species-independent. Absolute values vary considerably with the species. Relative P-face particle densities of the supporting cell microvilli tend to correlate with those of dendritic ending structures. Particle diameters are usually similar to corresponding structures and fracture faces in the four species. Apical structures of supporting and Bowman's gland cells in rat and dog show rod-shaped particle aggregates in the P- and pits in their E-faces. Neither sex-dependency nor an influence related to physiological treatments on the particle distributions could be demonstrated.

Animals↗
PubMed1980

The fine structure of the stomach mucosa of the Llama (Llama guanacoe). II. The fundic region of the hind stomach.

The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron desity of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.

Aminosalicylic Acid↗
PubMed1981

Structural evidence for insertion of collagen fibres to smooth muscle cells in the carotid arterial system of the giraffe (Giraffa camelopardalis).

Previous anatomical studies have failed to resolve the question relating to whether or not collagen fibers, like elastic fibres, are attached to smooth muscle cells in the arterial wall. The current ultrastructural study demonstrates the insertion of collagen fibres to the sarcolemmal dark areas in the smooth muscle cells of the carotid arterial system of the giraffe. It is concluded, therefore, that this morphological linkage between collagen and smooth muscle cells may facilitate transmission of the force of contraction between the cells and to the surrounding connective tissue framework since the myofilaments appear to be spatially placed in series with the extracellular collagen fibres at the sarcolemmal dark areas.

Animals↗
PubMed1981

Sister chromatid exchanges and heterochromatin.

The inter- and intrachromosomal distribution patterns of SCEs obtained with or without mutagen treatment are reviewed and compared, with each other as to their relation to heterochromatin and with the distribution patterns of chromatid aberrations that occurred either "spontaneously" in chromosomes of repair-defective human syndromes or after treatment with the mutagens (BrdU, ethylalcohol, DMBA, TMBA, maleic hydrazide, MMS, MMC). The conclusions are: No general rule is detectable for nonrandom involvement of heterochromatin in spontaneous SCEs. Mutagen-induced SCEs show the same or very similar distribution patterns as the spontaneous ones and are in no case as preferentially located as chromatid aberrations (which involve mainly the junctions between eu- and heterochromatin or other special regions). Therefore, a specific mutagen sensitivity of heterochromatin-aberrations does not exist (or is less pronounced) for SCEs. This supports the inference that different mechanisms underlie the origins of the two phenomena.

Animals↗
PubMed1988

Comparative anatomy of the foramen ovale in the Suina.

The structure of the foramen ovale from six species of Suina was studied using the scanning electron microscope. In each species, the foramen ovale, when viewed from the terminal part of the caudal vena cava had the appearance of a short tunnel. In the domestic pig (Sus scrofa), the wart hog (Phacochoerus aethiopicus) and the bush pig (Potamochoerus porcus) a fold of tissue projected from the caudal edge of the foramen ovale into the lumen of the left atrium. It constituted a large proportion of the tube, and its distal end was generally straight-edged. In some domestic pig hearts small holes were found in the fold, and single threads of tissue arose from its trailing edge. These were not found in specimens from the other pigs or from the collared peccary (Tayassu tajacu), which had a thin unfenestrated tissue fold ending in a straight edge. In both species of hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis) the fold of tissue was tubular, with strands of tissue extending from the atrial wall to insert on the outer surface of its proximal half. This tube was orientated at an angle of approximately 90 degrees to the caudal vena cava. Its walls were unfenestrated proximally and fenestrated distally, the latter forming a network over the end of the tube. The knotted appearance of the fold after birth suggested that the strands of the network had shortened and coalesced.

Animals↗