Trigeminal nerve: anatomic correlation with MR imaging

Through correlation with cryomicrotic sections, the appearance of the trigeminal nerve and its branches on magnetic resonance images is described in healthy individuals and in patients with tumors involving this nerve. Coronal images are best for defining the different parts of the nerve and for making a side-to-side comparison. Sagittal images are useful to demonstrate tumors involving the gasserian ganglion.     

Evidence for the involvement of glutamatergic system in the antinociceptive effect of ascorbic acid

This study examined the role of glutamatergic system in the ascorbic acid (AA)-induced antinociception in chemical behavioural models of nociception in mice. AA (0.3-10 mg/kg, i.p.) produced significant inhibition of both phases of formalin-induced licking, with mean ID50 values of 4.0 and 3.2 mg/kg and inhibitions of 56+/-4 and 60+/-7% for the early and second phase of the nociception caused by formalin, respectively. AA (1-5 mg/kg, i.p.) also produced significant inhibition of glutamate-induced nociception with mean ID50 value of 2.1 mg/kg and inhibition of 66+/-5%. Furthermore, AA (3 mg/kg, i.p.) caused marked inhibition of nociceptive response induced by intrathecal injection of glutamate, NMDA, AMPA, kainate and substance P, with inhibitions of 49+/-9, 42+/-7, 34+/-8, 38+/-5 and 65+/-8%, respectively. In contrast, AA at the same dose did not affect the biting response induced by the metabotropic agonist trans-ACPD. Taken together, present results indicate that AA, at low systemic doses, produces a rapid onset and consistent antinociception in mice when assessed in several models of chemical nociception, an action that is likely mediated by an interaction with ionotropic, but not metabotropic, glutamate receptors.     

Recombinant human interleukin-1 receptor antagonist protects early myeloid progenitors in a murine model of cyclophosphamide-induced myelotoxicity

Expression of hematoregulatory cytokines such as interleukin-1 (IL-1) in response to cytotoxic chemotherapy hastens hematopoietic recovery, but may also potentiate myelotoxicity if myeloid progenitors enter cell cycle before drug clearance. In the present study, the ability of recombinant human IL-1 receptor antagonist (IL-1ra) to protect hematopoietic progenitors was studied in a murine model of cyclophosphamide (CPA)-induced myelotoxicity. CF-1 female mice received 200 mg/kg CPA and either 10 mg/kg IL-1ra or an equal volume of 0.05% human serum albumin (HSA) intraperitoneally (i.p.), followed 12 hours later by IL-1ra or HSA. CPA and IL-1ra increased absolute neutrophil counts (ANCs) at days 2 (P = .001) and 14 (P = .0025) after CPA. In IL- 1ra-treated mice, colony-forming units granulocyte-macrophage (CFU- GM)/tibia were increased twofold and threefold at days 2 (P = .0047) and 7 (P = .023), respectively, whereas high proliferative potential colony-forming cells (HPP-CFC)/tibia were decreased twofold to threefold at 8 hours (P = .039) and 24 hours (P = .0033), but were approximately threefold higher than HSA-treated mice at day 7 after CPA. Coadministration of CPA and IL-1 enhanced myelotoxicity compared with mice injected with CPA and IL-1ra or HSA. In vivo, IL-1ra protected HPP-CFC, but not CFU-GM, from hydroxyurea suicide after a single dose of CPA, suggesting that IL-1ra inhibited cycling of HPP- CFC. In vitro, IL-1ra did not alter proliferation of CFU-GM, but inhibited IL-1-enhanced proliferation of HPP-CFC. These data suggest that IL-1ra acts as an indirect negative regulator of hematopoiesis and protects HPP-CFC from CPA, possibly by inhibiting IL-1-enhanced proliferation of early myeloid progenitors.