Neurotoxicity and pharmacokinetics of ventriculolumbar perfusion of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-gluco-pyranoside (MCNU) in dogs

Summary Ventriculolumbar perfusion of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU), a water soluble nitrosourea with log P-0.71, may be efficacious in the treatment of subarachnoid dissemination of malignant glioma. We used 2 dogs to study the neurotoxicity and pharmacokinetics of MCNU. MCNU (1 mg), dissolved in 10 ml of artificial CSF, was administered via the right lateral ventricle during a period of 18 to 42 min and the CSF was drained by lumbar puncture. The perfusion was repeated once a week for 10 consecutive weeks. No neurological and systemic symptoms were noted after perfusion. Histological examination of the brain and spinal cord showed local denudation of the ependyma and local subependymal spongy degeneration and gliosis in the lateral ventricle into which MCNU was administered in one dog and local denudation of the ependyma in the other. When administration was over a period of 21 to 38 min, the MCNU concentration in the lumbar CSF peaked at 11.11 to 50.67 g/ml, in 28 to 78 min. The area under the drug concentration-time curve (AUC) was 1152 g×min/ml on average, significantly larger than that of ACNU. The elimination phase followed linear kinetics and the half-time was 41.1 min on average, significantly longer than that of ACNU. These findings suggest that ventriculolumbar perfusion of MCNU may be effective in the treatment of subarachnoid dissemination of malignant glioma notwithstanding some local histological changes.     

Complete nucleotide sequence of mouse mammary tumor virus from jyg chinese wild mice: Absence of bacterial insertion sequences in the cloned viral gag gene

Mammary tumors of a newly isolated strain of Chinese wild mouse (JYG mouse) harbor exogenous mouse mammary tumor virus (MMTV). The complete nucleotide sequence of exogenous JYG-MMTV was determined on the proviral 5' long terminal repeat (LTR)(partial)-gag-pol-env-3' LTR (partial) fragment cloned into a plasmid vector and the cDNA sequence from JYG-MMTV producing cells. Similarly to the other MMTV species the LTR of JYG-MMTV contains an open reading frame (ORF). The amino acid sequence of the JYG-MMTV ORF resembles that of SW-MMTV (92% identity) and endogenous Mtv-7 (93% identity) especially at the C-terminal region. Thus, a functional similarity in T-cell receptor V beta recognition as a superantigen is implicated among these MMTV species. Analysis of the viral gag nucleotide sequence revealed that this gene is not disrupted by the bacterial insertion sequence IS1 or IS2, which have been reported to be present in the majority of the plasmids containing the gag region. Comparison of amino acid sequences of JYG-MMTV with those of BR6-MMTV showed that over 96% of the amino acids of gag, pol, protease and env products are identical. These results suggest the intact nature of the nucleotide sequence of the near full-length MMTV genome cloned in the plasmid.     

Tumor scintigraphy by the method for subtracting the initial image with technetium-99m labeled antibody

The method for subtracting the initial image from the localization image was evaluated for radioimmunoscintigraphy of tumors with technetium-99m (Tc-99m) labeled antibodies. Monoclonal antibodies were parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, both of which have been found to discriminate CEA in tumor tissues from the CEA-related antigens. After reduction of the intrinsic disulfide bonds, these antibodies were labeled with Tc-99m. In vivo studies were performed on athymic nude mice bearing the human CEA-producing gastric carcinoma xenografts. Though biodistribution results showed selective and progressive accumulation of Tc-99m labeled antibodies at the tumor site, high radioactivity in blood was inappropriate for scintigraphic visualization of the tumors within a few hours. We examined the subtraction of the initial Tc-99m image from the Tc-99m localization image after a few hours. Subtracted images of the same count reflected the in vivo behavior of the Tc-99m radioactivity. The subtracted scintigrams revealed excellent tumor images with no significant extrarenal background. Visualization of the tumor site was dependent on antigen-specific binding and nonspecific exudation. These results demonstrate that a method of subtraction of the initial image may serve as a potentially useful diagnostic method for an abnormal site for agents with a low pharmacokinetic value.     

Long-term immunological study on postoperative adjuvant treatment with interferon-gamma in patients with renal cell carcinoma who underwent nephrectomy

Previously, we reported the short-term immunological effects of postoperative adjuvant interferon-gamma (IFN-gamma) administration to renal cell carcinoma patients as determined by three-color flow cytometry. We now report the results of a long-term study on a larger number of subjects. Thirty-three patients with renal cell carcinoma received a prophylactic intramuscular injection of IFN-gamma (300 x 10(4) units per week) after nephrectomy. We evaluated immunological changes by measuring peripheral blood lymphocyte subsets including activated cytotoxic T lymphocytes (ACTL), cytotoxic T lymphocytes (CTL), activated suppressor T lymphocytes (ASTL), helper T lymphocytes (HTL), activated suppressor-inducer T lymphocytes (AITL), and suppressor-inducer T lymphocytes (SITL). We also estimated the natural killer (NK) activity by a cytolytic test. All 33 patients were examined for at least 12 months after the start of IFN-gamma injection, and 18 patients were examined for 30 months including the 6-month period following discontinuation of IFN-gamma injection. We found significant enhancement of the ACTL subset from the second week to the sixth month after the start of IFN-gamma injection. On the other hand, we found a significant decrease in the percentage of the HTL and SITL subsets for a long time after the start of injection. NK activity significantly increased throughout the period of administration, and it continued to increase for six months after discontinuation of IFN-gamma injection.     

Endosalpingiosis of nonmetastatic lymph nodes along the stomach in a patient with early gastric cancer: Report of a case

We report herein the case of a 32-year-old woman who underwent distal gastrectomy with D2 lymph node dissection for gastric cancer. Microscopic examination of the resected specimen revealed signet-ring cell carcinoma of the stomach with lymph node metastases, and endosalpingiosis in the normal lymph nodes. There was no evidence of malignancy in the peritoneal cavity. To our knowledge, no other case of endosalpingiosis in the lymph nodes along the stomach has ever been reported. The possible significance of endosalpingiosis is discussed following this case report.     

A 'long-term-potentiation-like' facilitation of hippocampal synaptic transmission induced by the nootropic nefiracetam

Nefiracetam, a nootropic agent, enhanced the slope of field excitatory postsynaptic potentials in the CA1 region of rat hippocampal slices to about 170% of basal levels, being evident still at 4-h washing-out of the drug. A similar sustained enhancement (>/=16 h after i.m. injection with nefiracetam) was observed in the population spikes recorded from the granular cell layer of the intact mouse hippocampus. Saturation of the enhancement in the synaptic strength occluded potentiation obtained with long-term potentiation (LTP) induced by high-frequency (tetanic) stimulation, and vice versa. Interestingly, the facilitatory action of nefiracetam was blocked by either the nicotinic acetylcholine (ACh) receptor antagonists, alpha-bungarotoxin and mecamylamine, or the selective protein kinase C (PKC) inhibitor, GF109203X, but in contrast, it was not affected by D-2-amino-5-phosphonovaleric acid (APV), a selective N-methyl-D-aspartate (NMDA) receptor antagonist. The results of the present study suggest that nefiracetam, whereas the action is independent of NMDA receptors, induces an 'LTP-like' facilitation of hippocampal synaptic transmission as a consequence of modulation of nicotinic ACh receptors and PKC. This may represent a likely mechanism underlying the cognition-enhancing actions of nefiracetam.     

Fractal dimensions in the occurrence of miniature end-plate potential in a vertebrate neuromuscular junction

1. Occurrence of miniature endplate potentials (MEPP) in the sartorius muscle of Rana catesbiana in high Mg2+ Ringer solution were observed in standard intracellular recording. Intervals and amplitudes of sequentially occurring MEPP were registered and analyzed. 2. Interval histograms of a time series of MEPP showed exponential-like pattern as reported in the classical study by Fatt and Katz (1952). The cumulative distribution of the intervals plotted in logarithmic axes showed two distinct phases. In shorter intervals (< 1s), curve along exponential decay was observed, and in longer intervals (> or = 1s) linear decay can be seen. The latter power-law relation gave dimensions of 4.111 +/- 0.812 (mean and S.D.). Self-similarity in longer range implies a time-scale invariant nature and may suggest fractal nature in restoration process of synaptic vesicles, while exponential decay in the short time interval range implies random release of transmitter packet from the readily releasable pool. 3. Fluctuation of amplitudes in sequentially occurred MEPP were analyzed according to Higuchi's cumulative route-length analysis. The estimates for sequential amplitude curve showed the power-law relation in a logarithmic plot whose inclination (= D) estimated with linear regression analysis was 1.996 +/- 0.007 (mean and S.D.). This results indicate that fluctuation in the amplitude of MEPP shows possible maximum complexity as a graphic curve in 2-D plane. Similar result was obtained for fluctuation of intervals of successively occurring MEPP.     

Induction of donor-specific hyporesponsiveness and prolongation of cardiac allograft survival by jejunal administration of donor splenocytes

BACKGROUND: Donor-specific immunosuppression is important in transplantation surgery. We examined the immunosuppressive effects of donor splenocytes administered postoperatively into the jejunum and the effect of such treatment on the survival of heterotopic vascularized cardiac allograft in rats. METHODS: Lewis (LEW, RT-1l) recipient rats were treated with 5x10(7) Brown Norway (BN, RT-1n) donor splenocytes for 5 days orally, intrajejunally, or subcutaneously. The immune responses of LEW treated with either donor BN or irrelevant Wistar King A (WKA, RT-1k) were examined by mixed lymphocyte reaction (MLR) and delayed type hypersensitivity (DTH). The effect of postoperative enteral treatment for 6 days with suboptimal dose of cyclosporine (CsA) on heterotopic cardiac allotransplantation was investigated. We measured the production of cytokines (interleukin [IL]-2, IL-4, IL-10, and interferon-gamma [IFN-gamma]) in the supernatant of MLR by ELISA. The effect of intravenous dose of GdCls to block Kupffer cell function was also investigated before the administration of splenocytes. RESULTS: MLR and DTH responses were strongly inhibited in a BN-restricted manner after jejunal or oral feeding of donor BN splenocytes but not by subcutaneous injection or injections by any routs of WKA splenocytes. The effect was more prominent in jejunal than oral feeding. Immunosuppression was associated with a significant inhibition of IL-2 and IFN-gamma production and increased concentrations of IL-4 and IL-10 in MLR supernatants. Immunosuppression was abrogated by pretreatment with GdCl3. Postoperative intrajejunal feeding of donor splenocytes with CsA significantly prolonged cardiac allograft survival time (18.7+/-7.3 vs. 9.9+/-1.7 days for control animals). CONCLUSION: Jejunal administration of splenocytes produces donor-specific immunosuppression and prolongs cardiac allograft survival. Our results suggest the involvement of T helper (Th) 2 cytokines and Kupffer cells in the induction of immune hyporesponsiveness, and indicate that this method represents a unique approach for induction of donor-specific immunosuppression.