Immunohistochemical studies on the transneuronal spread of virulent herpes simplex virus type 2 and its US3 protein kinase-deficient mutant after ocular inoculation.

The transneuronal spread of a virulent wild-type herpes simplex virus type 2 (HSV-2) and its US3 protein kinase-deficient (US3 PK-) mutant was immunohistochemically studied in mice after inoculations into the cornea, anterior chamber, tongue, and masseter muscle. After corneal inoculation, the wild-type virus was demonstrated in various brain stem areas including the trigeminal tract and nucleus, the reticular formation, and cerebellar nucleus group. Viral antigen-positive neurons were strictly confined to the ipsilateral spinal trigeminal nucleus in mice corneally infected with the US3 PK- mutant. No viral antigens were detected in the central nervous system (CNS) after inoculation with the mutant into the tongue and masseter muscle. However, when mice were immunosuppressed by treatment with cyclophosphamide, both the corneally infected mutant and wild-type virus could invade the CNS. The results suggest that the US3 PK- mutant principally retains the capacity to spread in the CNS.

Experimental autoimmune adrenalitis: a murine model for Addison's disease.

Experimental autoimmune adrenalitis was produced in mice by immunizing 8 times or more at intervals of 30 days with syngeneic adrenal extract mixed with Klebsiella O3 lipopolysaccharide (KO3 LPS) as a potent adjuvant. The cortex regions of the adrenal glands after the 8th injection were definitely infiltrated with polymorphonuclear leukocytes (PMN). The main infiltrates in the lesions after the 9th injection were replaced by mononuclear cells, such as small lymphocytes and macrophages, and further by fibrous connective tissues. There were no histological changes in the medullary regions. The repeated immunization developed the delayed type hypersensitivity to adrenal extract and production of anti-adrenocortical autoantibody in those immunized mice. Moreover, the adrenalitis could be produced in normal mice by transfer of spleen cells from hyperimmunized mice, suggesting the critical role of the cell-mediated immunity. This experimental model might be useful to study immunological phenomena in the pathogenesis of Addison's disease.

Afferent fibers in the hypoglossal nerve: a horseradish peroxidase study in the cat.

The existence of afferent fibers in the cat hypoglossal nerve was studied by transganglionic transport of horseradish peroxidase (HRP). Injections of wheat germ agglutinin-conjugated HRP (WGA-HRP) into the hypoglossal nerve resulted in some retrograde labeling of cell bodies within the superior ganglia of the ipsilateral glossopharyngeal and vagal nerves. A few labeled cell bodies were also present ipsilaterally within the inferior ganglion of the vagal nerve and the spinal ganglion of the C1 segment. Some of the labeled glossopharyngeal and vagal fibers reached the nucleus of the solitary tract by crossing the dorsal portion of the spinal trigeminal tract. Others distributed to the spinal trigeminal nucleus pars interpolaris and to the ventrolateral part of the medial cuneate nucleus by descending through the dorsal portion of the spinal trigeminal tract. In the spinal cord these descending fibers, intermingling with labeled dorsal root fibers, distributed to laminae I, IV-V and VII-VIII of the C1 and C2 segments. Additional HRP experiments revealed that the fibers in laminae VII-VIII originate mainly from dorsal root of the C1 segment.

A new vasodilator 3-isobutyryl-2-isopropylpyrazolo[1,5-a]pyridine (KC-404) has a dual mechanism of action on platelet aggregation.

3-Isobutyryl-2-isopropylpyrazolo [1,5-a]pyridine (KC-404) at a concentration of greater than or equal to 4.34 X 10(-5) M inhibited adenosine diphosphate-, arachidonic acid- and collagen-induced aggregation of rabbit platelets. In rabbit, KC-404 (0.5 and 2 mg/kg, i.v.) caused a decrease in weight of collagen strip extracorporeally superfused with arterial blood, because of a disaggregation of deposited platelet aggregates. This disaggregatory effect of KC-404 was markedly diminished by the pretreatment of animals with aspirin. KC-404 (greater than or equal to 4.34 X 10(-6) M) and its major metabolite diOH-KD-404 (greater than or equal to 3.78 X 10(-7) M) significantly potentiated the anti-aggregatory action of prostacyclin on rabbit platelets. KC-404 (greater than or equal to (4.34 X 10(-8) M) exerted a similar effect in rat platelets. KC-404 had no significant effect on 6-keto-PGF1 alpha and thromboxane A2 formation by rat aortic segment and rabbit platelets, respectively. KC-404 inhibited cyclic AMP phosphodiesterase (Ki = 91 microM). The present results indicate that KC-404 exhibits its anti-platelet effect via the inhibition of cyclic AMP phosphodiesterase activity in platelets and via the potentiation of anti-aggregatory activity of prostacyclin on platelets.

Mode of cerebral vasodilating action of KC-404 in isolated canine basilar artery.

3-Isobutyryl-2-isopropylpyrazolo[1,5-a]pyridine (KC-404) caused a potent and concentration-dependent relaxation in isolated canine basilar artery precontracted with prostaglandin (PG) F2 alpha attended by EC50 of 7.6 X 10(-8) g/ml. The relaxing action of KC-404 was little affected by the removal of vascular endothelium, whereas it was significantly diminished by pretreatment with indomethacin (10(-5) M) or acetylsalicylic acid (ASA) (10(-3) M). In PGF2 alpha-contracted canine basilar artery, KC-404-induced relaxation was markedly reversed to contraction by the subsequent addition of indomethacin (10(-5) M), ASA (10(-3) M) and phenidone (10(-4) M) by about 80%, 75% and 111%, respectively, whereas it was little affected by nordihydroguaiaretic acid (NDGA) (10(-5) M). Similar results were obtained when dipyridamole was used as a relaxant but, in contrast, papaverine-induced relaxation was little affected by indomethacin. KC-404 as well as PGI2 showed less potent or no relaxation in both PGF2 alpha-contracted rabbit aorta and KCl-contracted canine basilar artery as compared with PGF2 alpha-contracted canine basilar artery. In PGF2 alpha-contracted canine basilar artery, PGI2-induced relaxation was significantly augmented by pretreatment with KC-404 (10(-8) and 10(-7) g/ml). These results suggest that KC-404 might elicit cerebral vasorelaxation not dependent on vascular endothelium but remarkably dependent on a vasodilating cyclooxygenase metabolite, possibly PGI2.

KC-404: a potential anti-allergic agent with antagonistic action against slow reacting substance of anaphylaxis.

The mode of action of a novel compound, 3-isobutyryl-2-isopropylpyrazolo [1,5-a]pyridine (KC-404), as a potential anti-allergic agent has been investigated. KC-404 was shown to have a direct bronchodilator activity in guinea pig trachea in vitro and in anesthetized guinea pig in vivo. In addition, KC-404 had a fairly selective antagonistic action against slow reacting substance of anaphylaxis (SRS-A) on guinea pig ileum in vitro. In anesthetized guinea pigs, ED50 values for intravenously and intraduodenally injected KC-404 to inhibit SRS-A-induced bronchoconstriction were 0.0014 and 0.0065 mg/kg, respectively. Much higher doses were required to inhibit bronchospasms produced by histamine or particularly by acetylcholine. Orally administered KC-404, 0.001 to 0.1 mg/kg, also showed a selective inhibitory effect on increased vascular permeability by intradermal SRS-A in guinea pigs and rats. KC-404 inhibited the immunological release of mediators, notably SRS-A from sensitized guinea pig chopped lung in vitro at 10(-8) to 10(-4) g/ml. In vivo, the release of SRS-A, but not of histamine, mediated by a nonreaginic antibody in the peritoneal cavity of sensitized rats was inhibited by KC-404 at oral doses above 3 mg/kg. In a similar anaphylactic reaction but mediated by a reaginic antibody, KC-404 also inhibited SRS-A release at intraperitoneal doses of 2.5 to 10 mg/kg. The inhibitory activity on histamine release was less than half of that on SRS-A release. These results indicate that KC-404 is an orally active compound with a unique mode of action to inhibit preferentially both the effects and immunological release of SRS-A.