Scanning electron microscopic studies on the red pulp of the mink spleen

In order to obtain three-dimensional information on the fine architecture of the red pulp of the mink spleen, especially the circulation pattern in the red pulp, perfusion-fixed and freeze-cracked specimens were examined with a scanning electron microscope. A latticework was formed by elongated endothelial cells (rod cells) with side processes and the spongy reticular tissue. The outer surface of the sinus was covered with fine processes of reticular cells. Numerous sheathed arteries were found in the splenic cord. The sheath was composed of a few layers of flat reticular cells. The arterial capillaries of the red pulp opened directly into the cordal space. No evidence could be detected to prove or suggest any direct continuity between arterial capillaries and splenic sinuses. These results strongly support the concept of "open circulation", at least in the red pulp of the mink spleen, with the possibility of a "functionally closed circulation" under some physiological conditions.     

A histochemical study of the camel (Camelus bactrianus) duodenal glands

The complex carbohydrates in the camel duodenal glands were examined histochemically at light and electron microscopic levels. The duodenal glands of the camel were distributed in the submucosa 2 m caudal from the pylorus. These were branched tubuloalveolar glands. The terminal portion of each lobule was formed by only one type of mucous cell. The duodenal gland cells contained acidic and neutral carbohydrates. The mucous cells mainly contained sulfate and carboxyl carbohydrate with sialic acid, and they also contained a few neutral carbohydrates with different saccharide residues such as mannose, glucose, galactose, N-acetyl glucosamine and N-acetyl galactosamine. The results showed that the secretary granules of the duodenal glands in the camel contain mainly acidic carbohydrates. These findings seem to be the morphological characteristics of the duodenal glands in the camel.     

Duodenal Glands of the Pony (Equus caballus)

The ultrastructure and histochemistry of the duodenal glands of the pony (Equus caballus) was examined in four horses. Unlike that of most species except for the rabbit, the submucous glands of the horse contain two distinct cell types, serous and mucous. These cells are described.     

Retinal neuronal cell is a toxicological target of tributyltin in developing zebrafish

Organotins are among the most common marine pollutants in the world, as they are widely used as antifouling paint on ships and fishing nets. It has been reported that organotin preferentially accumulates in the central nervous system, especially in the retinal neurons of marine organisms including fish. In this study, we investigated the effects of waterborne tributyltin (TBT) on early-stage developing zebrafish (Danio rerio). Below the lethal concentrations, TBT specifically increased the number of apoptotic cells in the retina as well as some cells near trigeminal neurons, detected by terminal transferase-mediated nick-end-labeling staining. Apoptosis peaked at 60 hpf and decreased by 72 hpf, which was associated with macrophage accumulation. Furthermore, the effect of TBT was markedly inhibited by antioxidants, ascorbic acid or trolox. These results suggest that TBT preferentially induces apoptosis in the retinal neuron of developing zebrafish. Oxidative stress may be involved in this toxicological response.     

Control of the collagen fibril diameter in the equine superficial digital flexor tendon in horses by decorin

The distribution pattern of collagen fibril diameter in the equine superficial digital flexor tendon (SDFT) is known to differ in central and peripheral areas of some regions. This study reports the essence of collagen fibril differences among different regions of the equine SDFT by transmission electron microscopic (TEM) and high-voltage electron microscopic observations and biochemical analysis. The distribution of large collagen fibrils increased but the density of collagen fibrils decreased from the proximal metacarpal region to the distal metacarpal region. Large collagen fibrils with an irregular cross-sectional profile were found more frequently in the middle metacarpal region than in other regions. Three-dimensional reconstruction of images of irregularly shaped collagen fibrils revealed that these fibrils are formed through fusion of small collagen fibrils with large ones. The amount of decorin, which reportedly inhibits the lateral fusion of collagen fibrils, decreased in the direction of the distal metacarpal region. On the other hand, the size of decorin gradually increased in the direction of the distal metacarpal region. These results suggest that regional differences in collagen fibril distribution and density of collagen fibrils in the SDFT are due, at least in part, to fusion of collagen fibrils and the concomitant regional differences in the amount and size of decorin.     

Correlation between cytochrome P450 1A (cyp1a) mRNA expression and ambient phenanthrene and pyrene concentration in Javanese Medaka Oryzias javanicus

Fisheries Science - Cytochrome P450 1A (Cyp1a) catabolizes polycyclic organic compounds. In this study, we sequenced the cyp1a gene from two Javanese medaka Oryzias...     

Morphological Characterization of Gland Cells of the Glandular Sac Area in the Complex Stomach of the Bactrian Camel (Camelus bactrianus)

The morphology of the gland cells in the glandular sac area of the Bactrian camel and the composition of secretory substances were examined by histochemical methods. It was found that the gland cells of the glandular sac area were of the same type and size as those of the cardiac glands. The composition of secretory substances from the glandular sac area was the same as that of secretory substances from the cardiac glands. Moreover, secretory substances from the gland cells of the glandular sac area contained a great deal of acid glycoconjugates, such as sialic acid, in addition to neutral saccharides (fucose, mannose, glucose, N-acetyl-D-glucosamin, galactose and N-acetyl-galactosamin). Furthermore, immunohistochemical examination showed that progastricsin was present in the gland cells of the glandular sac area and the cardiac gland. In this study, histological analysis suggested that the stomach of the Bactrian camel is a single cavity stomach, formed as a result of multiple differentiation and growth of cardiac glands through the process of evolution.     

Gene Defect of Dermatan Sulfate Proteoglycan of Cattle Affected With a Variant Form of Ehlers-Danlos Syndrome

A defect of the core protein of dermatan sulfate proteoglycan was suspected in a Holstein calf affected with a variant form of Ehlers-Danlos syndrome. The mutation was a guanine-to-adenine transition at nucleotide position 254, which resulted in a serine-to-asparagine substitution of the bovine proteoglycan core protein. This substitution occurred in the serine-glycine dipeptide repeat that was suspected to be the binding portion of dermatan sulfate. This point mutation in the genome was also detected by the use of restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR) methods. The results of the RFLP and PCR indicated that the calf was a heterozygote of an abnormal gene and a normal gene of the core protein. The interpretation of these data revealed that the functional abnormality in cutaneous tissues of the calf was caused by an abnormal gene of the proteoglycan core protein, which induced a substitution of amino acid.     

Focal fatty liver in a heifer: utility of ultrasonography in diagnosis

A 30-month-old Holstein heifer presented with a history of decreased appetite and respiratory signs. Sonographic examination of the liver incidentally revealed an area of increased echogenicity between the portal vein and the gallbladder. The lesion was nonspherical and had no mass effect or displacement of the adjacent vessels. Its boundaries, to the liver, were geographic. The liver specimen was histologically compatible with a diagnosis of focal fatty liver change (FFLC). The sonographic features of focal fatty infiltration of the liver are characteristic. Recognition of the ultrasonographic data is important to differentiate FFLC from other lesions.