Exo-focal postischemic neuronal damage in the rat brain: alteration of [H]forskolin binding using in vitro autoradiography

We studied the alteration of intracellular signal transduction using quantitative autoradiography of the second messenger system in order to clarify the mechanisms of delayed neuronal damage in the remote areas of rat brain after transient focal ischemia. Chronological changes of [³H]forskolin binding sites were measured to demonstrate the striatal-nigral pathway after 90 min of right middle cerebral artery (MCA) occlusion and after such occlusion followed by 3 h, 6 h, 1 day, 3 days, 1 week, 2 weeks and 4 weeks of recirculation. [³H]Forskolin binding sites were found to be markedly decreased in the lateral segment of the caudate putamen supplied by the occluded MCA after 90 min of ischemia with no recirculation. On the contrary, there was no alteration on day 1, but 3 days after ischemic insult, marked reduction of [³H]forskolin binding sites was observed in the ipsilateral substantia nigra which lay outside the ischemic areas. This postischemic delayed phenomenon observed in the substantia nigra developed concurrently with ⁴⁵Ca accumulation, which was detected there in our previous study. The delayed reduction of [³H]forskolin binding sites in the substantia nigra observed in the present study indicates that striatonigral terminal degeneration at presynaptic sites is caused by precedent ischemic damage of the ipsilateral caudate putamen and that exo-focal postischemic neuronal death is caused by a transsynaptic process associated with the ischemic foci.     

Anorexia nervosa with neutropenia--response of neutrophils to G-CSF]

A 50-year-old woman with anorexia nervosa was admitted for evaluation of neutropenia (WBC 1,600/microliters). Her bone marrow was gelatinous, and myeloid cells had decreased. Homogeneous substance deposited in the marrow, stained by alcian blue (pH 2.5), indicative of acid mucopolysaccharides. CFU-G and CFU-GM were decreased in number and myeloid pool in the bone marrow also decreased. Anti-neutrophilic antibody was negative. Neutropenia may be related to myeloid hypoplasia, due to increase of acid mucopolysaccharides replacing adipose cells in the bone marrow under long-term mal-nutritional state. Neutrophils markedly increased by administration of rhG-CSF 5.0 micrograms/kg/day for 14 days without the first peak. Serum G-CSF level did not increase (less than 60 pg/ml). It is effective to administer G-CSF to anorexia nervosa with neutropenia.     

Inhibition by indomethacin of spontaneous mammary tumorigenesis in SHN mice

This experiment was designed to examine the effects of indomethacin, a potent prostaglandin synthesis inhibitor, on spontaneous mammary tumors in mice. The growth of established mammary tumors and the appearance of new tumors in multiparous SHN mice were significantly suppressed by the subcutaneous implantation of pellets of indomethacin diluted to 1/12 with cholesterol. Furthermore, the same treatment inhibited normal and preneoplastic mammary gland growth in virgin SHN mice. The pattern of estrous cycles, ovarian structure, and plasma prolactin levels were not affected significantly by the treatment. All results have demonstrated that indomethacin inhibits mammary tumorigenesis of mice primarily by route(s) other than the endocrine system under the present experimental conditions. Indomethacin would be the first agent that appears to inhibit the growth of spontaneous mammary tumors of palpable size in mice.     

Bacterial superantigen enhances cytokine production by T-helper lymphocyte subset-2 cells and modifies glomerular lesions in experimental immunoglobulin a nephropathy

Background The purpose of this study was to examine the effects of bacterial suporantigens, which can derange the immune response and contribute to the renal lesions of immunoglobulin A (lgA) nephropathy. Methods Twenty-five micrograms of a bacterial superantigen, staphylococcal enterotoxin B (SEB), was injected into IgA nephropathy-prone ddY mice intrathymically when they reached 6 weeks of age. Evaluation included measurement of albumin excretion in urine, immunoglobulin concentration, and lymphokine production in vitro, as well as analysis of T-cell receptor expression in splenic T-cell subsets and examination of renal histology by light and fluorescence microscopy. Results At 40 weeks of age, the serum level of IgA in these mice was substantially increased and the number of Vβ8⁺ CD4⁺splenic T-cells was significantly decreased compared with measurements in untreated controls. Both control and SEB-treated mice excreted less than 30 μg/mL of urinary albumin. In mice given SEB, the amount of interleukin 2 (IL-2) and tumor necrosis factor-α (T helper 1 [Th1]-type cytokines) produced by the in vitro-stimulated lymphocytes significantly decreased. whereas that of interleukin 4 (IL-4) and interleukin 6 (IL-6) (Th2-type cytokines) markedly increased compared with measurements in control mice. At 40 weeks of age, mice given SEB showed marked glomerular hypercellularity and enhanced glomerular C3 deposition by renal histology, compared with control mice. Conclusion These results suggest that bacterial superantigen SEB may modify glomerular lesions through activating Th2 cells, while inducing deletion of Th1 cells in this experimental model.     

The antiviral drug amantadine has a direct inhibitory effect on T-lymphocytes

We investigated the effect of the antiviral drug amantadine (AmTd) on polyclonal activation of thymic-dependent (T) and thymic-independent (B) lymphocytes from normal mice. In the present studies, T-lymphocytes are defined by their response to concanavalin A (Con A) and B-lymphocytes by their response to lipopolysaccharide (LPS). Polyclonal activator-induced lymphocyte proliferation was assessed by quantifying cellular incorporation of tritiated thymidine. The results show that, in a dose-dependent manner, AmTd exhibits at least 2-fold greater inhibitory activity against Con A-responding T-cells than against LPS-responding B-cells. Further, several findings demonstrate that AmTd has a direct inhibitory effect on T-lymphocytes. First, AmTd pulse treatment of isolated T-cells, but not accessory cells, abolished the T-cell response to Con A. Second, AmTd pulse treatment of the cytotoxic T-lymphocyte line, CTLL-2, markedly reduced their ability to undergo IL-2-induced proliferation. Third, proliferation of T-cells which had already undergone activation by ConA was inhibited by AmTd. Further, the finding that addition of IL-1, IL-2 or both to cultures failed to reverse inhibition of the response to ConA argues that AmTd did not interfere with endogenous production of these lymphokines. Possible implications of these findings are discussed.