Effects of 21-aminosteroid U-74389G on acute otitis media in a guinea pig model.

Free radicals participate in the development of disease under inflammatory conditions. Lipid peroxides such as malondialdehyde are regarded as markers of cell membrane damage by oxidative stresses. Previous work from our laboratory has demonstrated that lipidperoxidation is increased in acute otitis media in guinea pigs, implicating a role for free radicals as contributors to inflammation. In this study we examined the effect of lazaroid U-74389G, a 21-aminosteroid, on acute otitis media in guinea pigs. Streptococcus pneumoniae organisms were inoculated into the right tympanic cavity; sterilized phosphate-buffered saline solution was injected into the left ear to serve as a control. The guinea pigs were given intraperitoneal injections of 40 mg/kg of a lazaroid compound or its vehicle every 12 hours. Middle ear mucosa was collected and used for assay. We quantified lipid peroxide by means of the methylene blue-hemoglobin method and by means of measurement of thiobarbituric acid reactive substance. Lazaroid significantly (p < 0.05) suppressed production of lipid hyproperoxide of the middle ear mucosa of the guinea pigs with acute otitis media for up to 24 hours. These results suggest that lazaroid may reduce lipoperoxidation in the middle ear at an early stage of acute otitis media.

Novel oxidatively removable protecting groups and linkers for solid-phase synthesis of oligosaccharides.

Several new para-substituted benzyl- or phenyl-type protecting groups and their application to linkers for solid-phase synthesis are described. p-Acylaminobenzyl groups have higher acid stability than the p-methoxybenzyl (MPM) group, but are readily cleaved with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The p-azidobenzyl (Azb) group also has higher acid stability than the MPM group and can be removed much faster than the MPM group by DDQ oxidation after conversion of the azide group into the corresponding iminophosphorane. The acid stability of the p-azido-m-chlorobenzyl group (Cl-Azb) is higher than that of the Azb group. The former can be readily removed by DDQ oxidation after conversion of the azide group into the iminophosphorane. The p-acylaminophenyl glycoside linker can be readily obtained from p-nitrophenyl glycoside and can be readily cleaved by ammonium cerium(IV) nitrate (CAN) oxidation. This type of linker should be useful not only for the solid-phase synthesis of oligosaccharides but also for general solid-phase synthesis.

Immunohistochemical localization of manganese superoxide dismutase in rat vestibular dark cell regions.

A modified immunoglobulin peroxidase bridge sequence method was used to detect the localization of manganese superoxide dismutase (MnSOD), a superoxide radical (O2-) scavenging enzyme locating in mitochondrial matrix, in the vestibular labyrinth of pigmented rats. Strong positive MnSOD immunostaining was demonstrated in the dark cell regions of the ampullae, utricle, and common crus. The result provides for the first time direct evidence demonstrating the existence of mitochondrial O2- scavengers in the vestibular labyrinth and illustrates that the specific sites for vestibular MnSOD immunolocalization are the dark cell regions. This site specificity of MnSOD immunolocalization suggests that dark cell regions may possess high metabolic activity and may encounter constant threat from O2-. We assume MnSOD is needed in protecting some physiologic functions of the dark cell regions. Cell types showing negative MnSOD immunostaining may conceivably be relatively vulnerable to acute O2- damage.

Immunohistochemical localization of manganese superoxide dismutase in the rat cochlea.

There has been recent increasing interest in the involvement of superoxide radicals (O2-) and their scavenging enzymes, the superoxide dismutases, in the patho-physiology of certain diseases. Since mitochondria are significant intracellular sources of O2- and important targets of oxidant injury, determining the intracochlear localization of mitochondrial O2- scavenging enzyme may provide important insight into the pathogenesis of injury due to cochlear oxidants. In order to locate the mitochondrial O2- scavenging enzyme, manganese superoxide dismutase (MnSOD), the authors used a modified immunoglobulin peroxidase bridge sequence method to detect MnSOD in paraffin-embedded, formalin-fixed rat cochleas. Site-specific immunolocalization of MnSOD could be demonstrated in the cochlear labyrinth, suggesting that the generation of intracochlear O2- was possibly implicated in the metabolically active sites and sites rich in vascularity. This study also provided a useful probe for detecting MnSOD immunohistochemically from ethylenediamine tetra-acetic acid-treated materials without requiring an antigen retrieval procedure.

Heat shock proteins in acute otitis media.

Heat shock proteins (hsps) are essential for the survival of cells under an environmental insult. To elucidate the relationship between these intracellular proteins and acute otitis media (AOM), the authors studied hsp production in guinea pigs with AOM induced by inoculation of Streptococcus pneumoniae into the middle ear. Animals were sacrificed 1, 3, or 5 days after inoculation. Immunocytochemical study showed localization of hsp70 within the epithelium of infected ears, while the normal control epithelium showed very light staining. Western blot tests of the mucosal extraction confirmed the presence of hsp70 in otitis media. Enzyme-linked immunosorbent assay (ELISA) showed that hsp levels were higher in the infected mucosa than in the normal control mucosa. In contrast, hsp60 was not stimulated in infected ears. This study showed that hsp70, and not hsp60, was produced in the AOM model.

Superficial siderosis of the central nervous system: a case with an unruptured intracranial aneurysm.

We present a case of superficial siderosis (SS) of the central nervous system (CNS) with an unruptured intracranial aneurysm to illustrate that the commonly encountered unexplainable progressive sensorineural hearing loss (SNHL) can be an important sign for the early awareness of this rare disorder. The literature on SS is reviewed and the pathogenesis of SS is discussed.

Changes of dolichol and dolichyl fatty acyl esters during the germination and development of soybeans.

The amounts of dolichol and dolichyl fatty acyl esters and their composition in various parts of soybean seedlings were determined during germination and development. The dolichol content of cotyledons decreased during germination. Dolichyl fatty acyl esters were identified in cotyledons and the amount was estimated by high performance liquid chromatography. The relative amounts of short-chain dolichols of 15, 16, and 17 isoprene units increased during development of the seedlings. The homologue distribution of free dolichol was different from that of dolichyl fatty acyl esters. The relative amounts of dolichols with 16, 17, and 18 isoprene units were greater in free dolichol than in dolichyl fatty acyl esters. The percentages of long-chain saturated fatty acids in dolichyl fatty acyl esters, specifically 21:0, 22:0, 23:0, 24:0, and 25:0, increased during development. These fatty acids represented more than 40% of the fatty acids in dolichyl fatty acyl esters in stems. These results suggest that dolichyl fatty acyl esters are not a storage form of dolichol. The large accumulation of dolichol and dolichyl fatty acyl esters in the leaves, where photosynthesis takes place, suggests some other function.