Synthesis, pharmacological activity and biopharmaceutical characteristics of alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetates

The pro-drugs of alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetic acid(I) with a potent anti-inflammatory activity were synthesized in order to reduce its gastrointestinal side effects. Various esters synthesized were evaluated for their anti-inflammatory activity and ulcerogenicity. Among the compounds maintaining a potent activity of I, N,N-dimethylcarbamoylmethyl alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetate (II-18) showed excellent biopharmaceutical characteristics. The ulcerogenic effect of II-18 on the rat gastric mucosa was about 3 times less than that of I. It was suggested that II-18 may be an useful biolabile pro-drug for I among the compounds tested.     

Neurotized nevi of the oral mucosa: an immunohistochemical and ultrastructural analysis of nevic corpuscles

BACKGROUND: Nevic corpuscle (NC), a stacked lamellar structure reminiscent of Meissner corpuscle, is frequently observed in dermal melanocytic nevi. Although the heading 'neurotized' is classically used for these nevi, the exact neural nature of NC has been a topic of considerable debate. Neurotized nevi have received little attention in the dental literature, and there was no information on NC in oral melanocytic nevi. METHODS: Six cases of oral intramucosal nevi with a significant number of NC (two completely and four partially neurotized nevi) were examined immunohistochemically and ultrastructurally. RESULTS: NC was composed of closely piled laminar cells devoid of visible melanin. NC and associated spindle nevus cells were immunopositive for S-100 protein but negative for HMB-45, myelin basic protein and epithelial membrane antigen. Within NC, no reactivity for neurofilament protein, protein gene product 9.5 or peripherin was evident. Numerous CD34-positive dendritic cells were located between nevus cells and often encircled NC. Ultrastructurally, NC consisted of concentrically layered elongated cells with a slender lamellated cytoplasm rich in thin filaments and pinocytotic vesicles. Their cytoplasmic processes were focally covered by external basal lamina and continuous to spindle nevus cells. Occasional NC cells contained a few melanosomes. There was no interposed axon in NC. CONCLUSIONS: Despite the close resemblance to Meissner corpuscle, NC showed no axonal supply. NC cells lacked terminal Schwannian differentiation and appeared to be modified melanocytes with some perineurial ultrastructural characteristics. The presence of CD34-positive cells, presumably corresponding to endoneurial fibroblasts, further supports an organizational relationship of NC and peripheral nerve sheath elements.     

Axonal dystrophy in the posterior column nuclei of young adult epileptics with chronic phenytoin intoxication

Axonal spheroids in the posterior column nuclei of phenytoin-intoxicated epileptics were classified according to their predominant subcellular components into six types, and their incidences were compared with those in controls. Spheroids from phenytoin-intoxicated epileptics showed significantly higher proportions of the tubulomembranous (TM) and layered membrane loop (LML) types in the gracile nucleus, appearance of the same types in the cuneate nucleus, and a significant decrease of the neurofilamentous (NF) type in both nuclei. The incidences of the complex body (CB) and granular material types and of the homogeneous dense-body (HDB) type, which appeared only in the gracile nucleus, showed no difference between the intoxicated patients and the controls. The NF, CB and HDB types were therefore considered to be nonspecific. It was thought that chronic phenytoin intoxication might induce dystrophic changes, such as those characterized by the presence of the TM and LML types, in the axon terminals of the gracile and cuneate nuclei, possibly due to some abnormalities of the axoplasmic transport system.     

Immunohistochemical study of fibronectin, lysozyme, and alpha-fetoprotein (AFP) in human hepatocellular carcinoma

We have immunohistochemically localized fibronectin, lysozyme and alpha-fetoprotein (AFP) in 21 human hepatocellular carcinoma (HCC) tissues obtained by surgical resection at both light and electron microscopic levels. Three distinct distribution patterns of fibronectin (sinusoidal, periacinar, and pericellular patterns) were observed. The sinusoidal and periacinar patterns were mainly observed in HCC of pseudoglandular or trabecular patterns and of Edmondson's grade I or II, whereas the pericellular pattern was observed in HCC of compact or trabecular patterns and of Edmondson's III grade, suggesting that the pericellular fibronectin was rather associated with undifferentiated HCC. Electron microscopic observation of the pericellular fibronectin showed fibronectin to be present in the dilated intercellular spaces where microvilli were moderately developed. We observed intracytoplasmic staining of fibronectin in 2 of the 21 HCC cases. By immunoelectron microscopy, fibronectin was observed in the endoplasmic reticulum (ER) of some HCC cells. In the 21 HCC cases, lysozyme-positive cancer cells were observed in 10 cases, and AFP in 6 cases. At the ultrastructural level, lysozyme was identified in the ER and the perinuclear spaces of HCC cells, suggesting that lysozyme was synthesized by these cells. Lysozyme-positive cases tended to be more frequently observed in cases with the pericellular pattern of fibronectin rather than those with sinusoidal or periacinar patterns.     

An immunohistochemical study of MAP2 and clathrin in gerbil hippocampus after cerebral ischemia

Changes in MAP2 and clathrin immunoreactivity were studied in gerbil hippocampus after transient cerebral ischemia. MAP2 immuno-reactivity decreased significantly by 1 h in the subiculum-CA1 and CA2 areas which correspond to reactive change, while no decrease was observed in CA1 until day 4. Before the initiation of delayed neuronal death, MAP2 immunoreactivity was not changed in CA1. On the other hand clathrin immunoreactivity increased in the pyramidal cell layer of CA1 by 3 h after ischemia and remained high for 2 days. Clathrin immunoreactivity in the pyramidal cell layer of CA1 diminished after delayed neuronal death. The transient change of clathrin was noted especially in CA1 in the period prior to delayed neuronal death. These results imply an abnormal change in clathrin turnover after ischemia, which may participate in the pathogenesis of delayed neuronal death.