The predominant amount of research dealing with salivary gland tumors has been the histogenesis of different epithelial tumors and supplementally immunohistochemical and ultrastructural assessments. Salivary gland tumors, both benign and malignant, showed most heterogeneity of histopathology and histochemistry that considered biological roles of epithelial-mesenchymal interactions as biosynthesis of extracellular matrix proteins. Many primary salivary gland tumors histologically consist of most epithelial structures associated with modified or neoplastic myoepithelial cells which have been recognized to be complex properties of epithelial, mesenchymal and other structural components, although normal myoepithelial cells showed more simple properties. Recently, modified or neoplastic myoepithelial cells in salivary gland tumors were not shown to originate from myoepithelial cells and were possible ductal cells in origin. However those uncomprehensive or non-distinct properties of histogenetic concepts in human salivary gland tumors can not be instead of animal studies. Moreover rodent submandibular glands have shown specific structures as granular convoluted tubules which are the source of growth factors or biologically active peptides, and human specimens may have a possibility to synthesize or produce growth factors. Thus the present review deals with critical evidence or possible identification of specific target subjects during histogenesis of salivary gland tumors, as well as different histologic types of tumor lesions without common classification. With the continued interest of salivary gland research under pathologic implication, unique systems for identification or molecular manipulations of salivary gland tumors may provide new opportunities in the health sciences.

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A fluorescent glucose analogue, 6-deoxy-N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl)-aminoglucose (NBDG) has been used for studies of glucose transport. The fluorescence from NBDG was observed with a confocal laser scanning microscope (CLSM). The fluorescence in the blood vessels, however, could not be observed even though substantial amount of NBDG was present in the blood. We investigated the causative factors responsible for this non-fluorescence. It was found that NBDG made an uncertain complex with hemoglobin which decreased the fluorescence intensity of NBDG. However, it appeared that the principal causative factor was absorbance of excitation and emission wave lengths by hemoglobin which resulted in a significant decrease of fluorescence intensity from NBDG in the blood vessels.

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Superoxide radicals appear to play important roles in the pathogenesis of various gastric mucosal lesions. To add to a greater understanding of the pathogenesis of the various gastric mucosal lesions caused by oxygen-derived free radicals, we examined the distribution of copper-zinc superoxide dismutase (Cu, Zn-SOD) in normal human gastric mucosa using a direct immunoperoxidase method under light and electron microscopy. Under light microscopy, we detected Cu, Zn-SOD in propria gland cells but not in foveolar cells of the fundic mucosa or in antral gland cells. With electron microscopy, Cu, Zn-SOD was detected in the ultrastructural morphology of parietal and chief cells. In parietal cells, it was present mainly in the cytoplasm, partially on the outer membrane of mitochondria, and in the nuclei, and in chief cells, in the cytoplasm. Our findings suggest that Cu, Zn-SOD plays important roles in scavenging oxygen radicals generated in the cytoplasm.

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Tartrate-resistant acid phosphatase (TRAP) activity in the metaphyseal and diaphyseal osteoblasts of the tibiae of young growing rats was histochemically examined. To evaluate the histochemical reactivity of TRAP, both the azo-dye method and the lead-salt method were used. In metaphyseal bone trabeculae, both osteoblasts and osteoclasts existed on the bone surfaces, indicating active bone remodeling. The osteoblasts appeared round or columnar in shape with abundant cytoplasm. Most osteoblasts were TRAP-positive and the reaction product was distributed throughout the cytoplasm, producing a granular appearance. Osteoclasts had the most intense TRAP activity among bone cells. In the endosteum of diaphyses, the bone surfaces were commonly covered with osteoblasts, indicating predominant bone formation. The osteoblasts in these areas were TRAP negative. On some endosteal surfaces, where bone remodeling was taking place, the osteoblasts co-existed with osteoclasts. In these areas the osteoblasts were TRAP-positive. From these results, it was shown that TRAP-positive osteoblasts existed, and that the osteoblasts located at or near the regions where osteoclastic bone resorption was taking place, became TRAP positive.

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Human urinary trypsin inhibitor (UTI) is the functional domain of serum inter-α-trypsin inhibitor. Rat urine also contains UTI-like immunoreactivity. To clarify the source of rat UTI, we performed a combination of reverse transcription-polymerase chain reaction (RTPCR), in situ hybridization and immunohistochemistry. The expression of UTI mRNA was detected by RT-PCR only in the liver and not in any other rat organs, including the kidney. In situ hybridization revealed that UTI transcripts are located exclusively in the hepatocytes and not in the nonparenchymal cells of the liver. On light microscopic immunohistochemistry, not only the hepatocytes but also the Kupffer cells of liver and the proximal tubules of kidney were immunostained with anti-UTI antibody. Immunoelectron microscopy further demonstrated that hepatocyte UTI-immunoreactivity is localized primarily on the cell surface facing the sinusoidal capillary and is also found in the Golgi apparatus. In contrast, the reactivity of Kupffer cell and proximal tubular epithelial cell was found primarily in the lysosomes. These results indicated that the liver is the only site for production of rat UTI, and that the kidney does not produce rat UTI but reabsorbs it from the primary urine.

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The proposed combination of three histochemical methods facilitates the demonstration of microscopic anatomy, Nissl content of neurons, lipofuscin accumulation and associated cytopathological changes, if any, in one brain section. Form-aldehyde fixed paraffin sections were stained with a modified Weil's method, cresyl violet and pyronin Y in sequence, dehydrated, cleared and mounted in DPX. The slides were studied under a fluorescence microscope. The fibre system stained grey. The Nissl substance and lipofuscin stained violet and pink, respectively. On exposure to UV light, the pink stained pigment emitted golden-yellow fluorescence, resembling the auto-fluorescence of unstained lipofuscin. The final results were remarkably reproducible.

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The present study was designed to examine the bone-titanium interface of the titanium-coated or titanium rod implants inserted for 28 days in the tibiae of 6-week-old rats. Basically, there were hardly differences in the interfaces between the titanium-coated and titanium rod implants. Light microscopically, titanium layer appeared to make direct contact with the mature bone or poorly mineralized layer, and one or a few layers of slender cells were localized contacting the titanium. Ultrastructurally, titanium came in direct contact with either the bone, the poorly mineralized layer consisting of delicate fibril-like structures or the slender cell layer through a thin amorphous zone (20-40nm). This amorphous zone was positive for ruthenium red which has a high affinity for proteoglycans. Part of the interfacial slender cells had abundant rough-ER and glycogen granules as osteoblasts, while some slender cells had well-developed rough-ER but no glycogen, and often endocytosed the titanium fragments, as shown in the fibroblasts.
These findings suggest that an amorphous zone consisting of proteoglycans is thus essential for attachment between the slender cell layer, poorly mineralized layer or mature bone and titanium. Furthermore, slender cells close to the implant may also be considered to function as either osteoblasts for bone production adjacent to the implant or as scavengers for the removal of interfacial debris at the bone-titanium interface.

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Using a specific monoclonal antibody (mAb) recognizing the rat interleukin-2 receptor (IL-2R) and immunocytochemical techniques, we examined the expression of IL-2R in rat anterior pituitary and adrenal cells in vitro. IL-2R immunoreactivity was seen in a variety types of cells in both the pituitary and adrenals. Under the condition to detect the IL-2R-like immunoreactivity, we found that overnight preincubation with IL-2 enhanced the immunostaining in these cells. Moreover, co-incubation of the cells with dexamethasone attenuated the effect of IL-2 on the IL-2R-like immunostaining. These findings indicate that IL-2R expression in the pituitary and adrenal cells is influenced by IL-2 and glucocorticoid, and support the hypothesis that IL-2 is an immunomediator affecting the pituitary and the adrenal function.

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The clinical phenotypes of Bowen's disease and squamous cell carcinoma (SCC) are very different although the origins of these tumors are epidermal keratinocytes. Here we compared the degree of apoptosis in Bowen's disease and squamous cell carcinoma. In Bowen's disease, several individual tumor cells showed apoptosis. In contrast, apoptosis was not found at the tumor mass where the atypical epidermal cells invaded into the dermis in cases of Bowen's carcinoma and squamous cell carcinoma. The possible molecular mechanisms underlying different behaviors of Bowen's disease and SCC are also discussed.

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The morphological features and distribution of serotonergic fibers in the spinal cord of 7-and 12-month-old zitter mutant rats which are characterized by abnormal metabolism of superoxides were examined immunohistochemically. In the zitter rat spinal cord, several aberrant serotonergic fibers characterized by swollen varicosities were intermingled with normal serotonergic fibers. These aberrant fibers increased in number by aging. Serotonergic neuron system seem to be vulnerable to superoxide radicals. Thus, these aberrant serotonergic fibers may reflect the degeneration by superoxide radicals. These aberrant fibers were never found in young adult or 12-month-old SD rats. The appearance of these fibers has been reported in the aged (30 months) rat spinal cord. Based on the morphological similarity, the present study indicates the early onset of age-related change in serotonergic fibers in the spinal cord of zitter rats.

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