The N-Methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) suppresses enfturane-induced opisthotonus in mice

We determined whether enflurane-induced opisthotonus in ddN mice is mediated by N-methyl-D-aspartate (NMDA) receptor using NMDA receptor antagonists dizocilpine (MK-801) and ketamine. Animals were given intraperitoneal injections of 0.2ml saline (control), 2.5 or 5.0mg·kg^–1 dizocilpine in saline, or 20 or 40mg·kg^–1 ketamine is saline 20min prior to exposure to 2.0% enflurane. Incidence of opisthotonus measured during exposure to enflurane for 20min was 49% (n = 51) in saline (control) group, 6.7 (P 0.01 vs control, n = 30) and 15.0% (P 0.01, n = 40) in 2.5 and 5.0mg·kg^–1 dizocilpine group, respectively, and 43.9 (NS, n = 41) and 40.0% (NS, n = 40) in 20 and 40mg·kg^–1 ketamine group, respectively. These results strongly suggest that enflurane-induced opisthotonus is mediated by NMDA receptor. Ketamine failed to suppress significantly due to possibly small dosages. Further, dizocilpine itself produced severe seizures during preenflurane period (30.0 and 40.0% in 2.5 and 5.0mg·kg^–1, respectively), which may be a novel finding.(Komatsu H, Nogaya J, Anabuki D, et al.: The N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) suppresses enflurane-induced opisthotonus in mice. J Anesth 7: 519–522, 1993)     

Radioimaging of human glioma xenografts with 123I labeled monoclonal antibody G-22 against glioma-associated antigen

Summary Monoclonal antibody (MCA) G-22 is directed against a human glioma-associated surface antigen. Its availability for the radioimmunodetection of human glioma was analyzed by utilizing the xenografts in athymic mice. Nude mice with subcutaneous grafts of U251-MG or U251-SP glioma received intravenous administration of ¹²³I or ¹³¹I labeled F(ab)2 fragment or whole immunoglobulin. Results of radioimaging revealed that ¹²³I-labeled antibody was better than the ¹³¹I-labeled. It was also noted that administration of ¹²³I-labeled F(ab)2 fragment of G-22 MCA enabled the imaging of human glioma xenografts weighing 80–650 mg after 48 hours. When biodistribution of ¹²³I MCA was compared between G-22 and control antibodies, the percentages of dose/g in tumors were 5.228–1.799 at 30 hours and 4.112–1.132 at 48 hours with G-22 and they were 4.164–1.248 and 0.314–0.142 with control. The tumor/blood ratio until 72 hours after injection was constantly above 1 with G-22 and less than 1 with control antibody. These results indicate the potential usefulness of G-22 MCA for the radioimmunodetection of human gliomas.     

Cdc7 kinase is required for postnatal brain development

The evolutionally conserved Cdc7 kinase plays crucial roles in initiation of DNA replication as well as in other chromosomal events. To examine the roles of Cdc7 in brain development, we have generated mice carrying Cdc7 knockout in neural stem cells by using Nestin-Cre. The Cdc7^Fl/Fl Nestin^Cre mice were born, but exhibited severe growth retardation and impaired postnatal brain development. These mice exhibited motor dysfunction within 9 days after birth and did not survive for more than 19 days. The cerebral cortical layer formation was impaired, although the cortical cell numbers were not altered in the mutant. In the cerebellum undergoing hypoplasia, granule cells (CGC) decreased in number in Cdc7^{Fl/F l}Nestin^Cre mice compared to the control at E15-18, suggesting that Cdc7 is required for DNA replication and cell proliferation of CGC at mid embryonic stage (before embryonic day 15). On the other hand, the Purkinje cell numbers were not altered but its layer formation was impaired in the mutant. These results indicate differential roles of Cdc7 in DNA replication/cell proliferation in brain. Furthermore, the defects of layer formation suggest a possibility that Cdc7 may play an additional role in cell migration during neural development.     

Microsomal Cytochrome P-450 Monooxygenase System and Its Drug-metabolizing Activity after Partial Portal Vein Ligation in the Rat

RID=" ID=" <E5>Correspondence to:</E5> K. Izuishi, M.D.     

Lidocaine-metabolizing Activity after Warm Ischemia and Reperfusion of the Rat Liver In Vivo

The effect of warm ischemia on lidocaine-metabolizing activity was examined in vivo. Total liver ischemia was produced for 1 hr in Sprague-Dawley rats by clamping the portal vein and hepatic artery at the hilum. Livers were then reperfused, and liver microsomes were prepared before and 0, 2, 6, and 24 hr, and 3, 6, and 10 days after reperfusion. Microsomal lidocaine-metabolizing activity and cytochrome P-450 content were examined. Lidocaine N-deethylase activity was decreased from 2.25 ± 0.33 to 0.97 ± 0.21 nmol/mg protein/min (mean ± SD) 24 hr after reperfusion. This inhibition was prolonged, and activity gradually recovered after 10 days. The cytochrome P-450 content showed the same tendency. On the other hand, serum levels of alanine aminotransferase increased significantly 2 hr after reperfusion and returned to control levels 3 days after reperfusion. Liver blood flow recovered rapidly after unclamping and reached baseline levels within 6 hr. Our results suggest that after warm ischemia, prolonged hepatic dysfunction in drug metabolism, which cannot be detected by evaluating serum enzymes or liver blood flow, exists at the microsomal level.     

Relationship between striatal [123I]β-CIT binding and four major clinical signs in Parkinson’s disease

We investigated the correlation between clinical severity and striatal [123I]-CIT binding in 12 patients with Parkinson's Disease (PD: 6 men and 6 women, age: 65 +/- 7 years, Hoehn & Yahr stage: 1 to 3). The clinical severity of PD patients was measured with the Unified Parkinson's Disease Rating Scale (UPDRS) after withdrawal of antiparkinsonian medication at least 12 hours before assessment. [123I]beta-CIT binding in the caudate and putamen was measured at 3 hours [V'3 (day 1)], and at 24 hours [V'3 (day 2)) after tracer injection with small square ROIs. The specific striatal uptake index (day 2) was calculated with large square ROIs that encompassed the whole striatum. The best correlation (r = -0.82, p < 0.0012) was between putamenal V'3 (day 2) and the motor UPDRS scores. When the motor UPDRS scores were divided into four subscales, bradykinesia was the only sign that correlated significantly with putamenal V'3 (day 2) (r = -0.81, p < 0.002). [123I]beta-CIT SPECT is a useful marker of disease severity in PD with potential utility in the serial monitoring of disease progression.     

Dendritic cells fused with allogeneic colorectal cancer cell line present multiple colorectal cancer-specific antigens and induce antitumor immunity against autologous tumor cells.

The aim of antitumor immunotherapy is to induce CTL responses against autologous tumors. Previous work has shown that fusion of human dendritic cells and autologous tumor cells induce CTL responses against autologous tumor cells in vitro. However, in the clinical setting of patients with colorectal carcinoma, a major difficulty is the preparation of sufficient amounts of autologous tumor cells. In the present study, autologous dendritic cells from patients with colorectal carcinoma were fused to allogeneic colorectal tumor cell line, COLM-6 (HLA-A2(-)/HLA-24(-)), carcinoembryonic antigen (CEA)(+), and MUC1(+) as an alternative strategy to deliver shared colorectal carcinoma antigens to dendritic cells. Stimulation of autologous T cells by the fusion cells generated with autologous dendritic cells (HLA-A2(+) and/or HLA-A24(+)) and allogeneic COLM-6 resulted in MHC class I- and MHC class II-restricted proliferation of CD4(+) and CD8(+) T cells, high levels of IFN-gamma production in both CD4(+) and CD8(+) T cells, and the simultaneous induction of CEA- and MUC1-specific CTL responses restricted by HLA-A2 and/or HLA-A24. Finally, CTL induced by dendritic cell/allogeneic COLM-6 fusion cells were able to kill autologous colorectal carcinoma by HLA-A2- and/or HLA-A24-restricted mechanisms. The demonstration of CTL activity against shared tumor-associated antigens using an allogeneic tumor cell line, COLM-6, provides that the presence of alloantigens does not prevent the development of CTL with activity against autologous colorectal carcinoma cells. The fusion of allogeneic colorectal carcinoma cell line and autologous dendritic cells could have potential applicability to the field of antitumor immunotherapy through the cross-priming against shared tumor antigens and provides a platform for adoptive immunotherapy.     

Granulomatous/sarcoid-like reactions in the setting of programmed cell death-1 inhibition: a potential mimic of disease recurrence

Nivolumab and pembrolizumab are humanized IgG4 monoclonal antibodies against programmed cell death 1 (PD-1). Although these agents are effective in treating advanced melanoma, non-small-cell lung carcinoma, and other types of cancers, various adverse events have been reported. Cutaneous adverse events are particularly prevalent and, while granulomatous/sarcoid-like reactions are uncommon, they are increasingly recognized as immune-related adverse events associated with immune checkpoint inhibitors. Herein, we report two cases of granulomatous/sarcoid-like reaction with foreign material, mimicking metastatic malignancy after PD-1 inhibitor treatment. Clinicians should be aware of the existence of cutaneous lesions and perform biopsy if needed to prevent misdiagnosis and unnecessary adjustments to immunotherapy.