Selective enhancement of thrombopoietic activity of PEGylated interleukin 6 by a simple procedure using a reversible amino-protective reagent

We developed a novel method for the chemical modification of cytokines with synthetic polymers to increase the therapeutic efficacy of the former in vivo. A pH-reversible amino-protective reagent, dimethylmaleic anhydride (DMMAn), was used for modification of interleukin-6 (IL-6) with polyethylene glycol (PEG). The novel PEG-conjugated IL-6 (DmPEG-IL-6), which had been pretreated with DMMAn before PEGylation, showed up to a 140% increase in in vitro specific activity compared with PEG-IL-6 that had been synthesized by the previous method. Moreover, DmPEG-IL-6 caused thrombopoiesis more potently in mice than PEG-IL-6. The DmPEG-IL-6 Fr.1, having 3-4 PEG chains attached to the cytokine, showed the strongest thrombopoietic effect among the DmPEG-IL-6s with different molecular sizes that were tested. PEG-IL-6 Fr.1 had a 500-fold higher potency in stimulating thrombopoiesis than native IL-6 and DmPEG-IL-6 Fr.1 achieved a threefold higher thrombopoietic effect than PEG-IL-6 Fr.1. In addition, side-effects, such as an increase in the plasma fibrinogen level, were not observed after injection of either PEG-IL-6s or DmPEG-IL-6s. These results suggest that PEGylation with DMMAn pretreatment may become a useful means for clinical cytokine delivery.

Schedule-dependent synergism and antagonism between raltitrexed ("Tomudex") and methotrexate in human colon cancer cell lines in vitro

The folate-dependent enzymes are attractive targets for cancer chemotherapy. Methotrexate (MTX), which inhibits dihydrofolate reductase, has been widely used for the treatment of solid tumors and hematological cancers. Raltitrexed ("Tomudex") ), which inhibits thymidylate synthase, is a novel anticancer agent active against colorectal cancer and some other solid tumors. We studied the optimal schedule of raltitrexed and MTX in combination against four human colon cancer cell lines Colo201, Colo320, LoVo, and WiDr. These cells were simultaneously exposed to raltitrexed and MTX for 24 h, or sequentially exposed to raltitrexed for 24 h followed by MTX for 24 h, or vice versa. Cell growth inhibition after 5 days was determined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of drug combinations at the concentrations of drug that produced 80% and 50% cell growth inhibition (IC(80) and IC(50)) were analyzed by the isobologram method (Steel and Peckham, 1979). Cytotoxic interactions between raltitrexed and MTX were schedule-dependent. The simultaneous exposure to raltitrexed and MTX showed additive effects in Colo201, LoVo and WiDr cells and antagonistic effects in Colo320 cells. The sequential exposure to raltitrexed followed by MTX produced additive effects in all four cell lines. The sequential exposure to MTX followed by raltitrexed produced synergistic effects in Colo201, LoVo and WiDr cells and additive effects in Colo320 cells. These findings suggest that the sequential administration of MTX followed by raltitrexed produces more than the expected cytotoxicity and may be the optimal schedule at the cellular level. Further in vivo and clinical studies will be necessary to determine the toxicity and to test the antitumor effects of sequential administration of MTX followed by raltitrexed proposed on the basis of the in vitro synergism.

Independent anchoring and assembly mechanisms of INAD signaling complexes in Drosophila photoreceptors

In Drosophila photoreceptors the multivalent PDZ protein INAD organizes the phototransduction cascade into a macromolecular signaling complex containing the effector PLC, the light-activated TRP channels, and a regulatory PKC. Previously, we showed that the subcellular localization of INAD signaling complexes is critical for signaling. Now we have examined how INAD complexes are anchored and assembled in photoreceptor cells. We find that trp mutants, or transgenic flies expressing inaD alleles that disrupt the interaction between INAD and TRP, cause the mislocalization of the entire transduction complex. The INAD-TRP interaction is not required for targeting but rather for anchoring of complexes, because INAD and TRP can be targeted independently of each other. We also show that, in addition to its scaffold role, INAD functions to preassemble transduction complexes. Preassembly of signaling complexes helps to ensure that transduction complexes with the appropriate composition end up in the proper location. This may be a general mechanism used by cells to target different signaling machinery to the pertinent subcellular location.

Effective cancer targeting using an anti-tumor tissue vascular endothelium-specific monoclonal antibody (TES-23)

Immunoconjugate targeting of solid tumors has not been routinely successful because the endo-thelial cells of blood vessels act as a physical barrier against the transport of macromolecules, such as antibodies. In the present study, we attempted to achieve tumor vascular targeting with an anti-tumor tissue endothelium-specific monoclonal antibody (TES-23). TES-23, an IgG1 monoclonal antibody raised against rat KMT-17 fibrosarcoma-derived endothelial cells, was covalently conjugated with neocarzinostatin (NCS) in a previous study. The TES-23-NCS conjugate induced tumor hemorrhagic necrosis, and showed marked anti-tumor effects against rat KMT-17 fibrosarcoma. This result prompted us to investigate whether this approach would be applicable to various other types of solid tumors. One hour after injection of (125)I-labeled TES-23 into BALB / c mice bearing Meth-A fibrosarcoma and Colon 26 adenocarcinoma, the tumor accumulation of TES-23 was greater than that of the control IgG. In the present study, we report the anti-tumor effects of this monoclonal antibody in mice bearing Meth-A fibrosarcoma. Mice treated with the immunoconjugate showed improved survival with no side effects. This result indicates that common antigens may be found in different kinds of tumor endothelial cells, and that TES-23 might recognize these antigens.

C-Type natriuretic peptide inhibits proliferation and monocyte chemoattractant protein-1 secretion in cultured human mesangial cells

BACKGROUND

Mesangial cell proliferation and matrix accumulation are hallmarks of various progressive glomerular diseases. We examined whether C-type natriuretic peptide (CNP) that is known to regulate the proliferation of vascular smooth muscle cells could modulate these pathological processes using human glomerular mesangial cells (GMCs) in culture.

METHODS

Proliferation of GMCs cultured with different concentrations of CNP-22 for 48 h was determined by a colorimetric assay using a tetrazolium salt. Monocyte chemoattractant protein-1 (MCP-1) and type IV collagen secretion into the culture media by GMCs in the presence or absence of CNP-22 were evaluated by ELISA. Expression of mRNA for natriuretic peptide receptor B (NPR-B), a specific receptor for CNP, was examined by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

CNP-22 (1-10 microM) inhibited serum-induced GMC growth in a dose-dependent manner. The amount of MCP-1 in the culture supernatant was increased approximately 2.4-fold by 5 microg/ml of lipopolysaccharide. This increase was inhibited by CNP-22 at 0.1-1 microM in a dose-dependent fashion. CNP-22 (10 microM) inhibited GMC type IV collagen secretion stimulated by 20 ng/ml of platelet-derived growth factor. Expression of NPR-B mRNA was confirmed in GMCs by RT-PCR.

CONCLUSIONS

CNP suppresses GMC proliferation and MCP-1 and type IV collagen secretion by GMCs. It may have a therapeutic potential against human proliferative glomerular diseases, especially those with the involvement of monocytes.

Molecular design of polyvinylpyrrolidone-conjugated interleukin-6 for enhancement of in vivo thrombopoietic activity in mice

Functional polyvinylpyrrolidone (PVP) was synthesized as a novel polymeric modifier for polymer-conjugated cytokines, and its efficiency and applicability as a drug delivery system (DDS) were evaluated. PVP with a carboxyl group at one end of the main chain was prepared by radical polymerization (M(n): 6000, M(w)/M(n): 1.14) with the aid of 4,4'-azobis(4-cyanovaleric acid) as a radical initiator and 3-mercaptopropionic acid as a transfer agent. Interleukin-6 (IL-6) was covalently conjugated via the formation of amino bonds between the lysine amino groups of IL-6 and PVP. PVP-conjugated IL-6, in which 60% of the fourteen lysine amino groups of IL-6 were estimated to be coupled with PVP (M-PVP-IL-6), showed more than 50-fold greater thrombopoietic potency in vivo than native IL-6. No side effects, such as body weight loss, were observed in the M-PVP-IL-6 treated mice. These results indicate that PVP as a polymeric modifier is a promising DDS for clinical application of cytokines and other therapeutic agents.

Platelet-derived growth factor, basic fibroblast growth factor, and interferon gamma increase type IV collagen production in human fetal mesangial cells via a transforming growth factor-beta-dependent mechanism

BACKGROUND

Glomerulosclerosis is characterized by glomerular accumulation of extracellular matrix following mesangial cell proliferation. The precise pathomechanism of glomerulosclerosis is still undetermined. Platelet-derived growth factor (PDGF) and basic fibroblast growth factor (b-FGF) are known to be mitogenic for mesangial cells, and interferon gamma (IFN-gamma) is known to have an inhibitory effect on mesangial cell proliferation. We attempted to clarify the role of these cytokines on mesangial matrix production using cultured human fetal mesangial cells (HMC).

METHODS

HMC were incubated with these cytokines for 24-72 h and the levels of type IV collagen and TGF-beta in the cell supernatants were measured by enzyme immunoassay.

RESULTS

PDGF, b-FGF, and IFN-gamma stimulated type IV collagen production by HMC in a dose- and time-dependent manner. The anti-TGF-beta neutralizing antibody clearly inhibited their stimulatory effect on type IV collagen production. PDGF and b-FGF also stimulated TGF-beta production by HMC in a dose-dependent manner, although IFN-gamma did not.

CONCLUSION

PDGF, b-FGF, and IFN-gamma stimulate type IV collagen production in cultured HMC via a TGF-beta-dependent mechanism.

Selective vulnerability to radiation in the hippocampal dentate granule cells

BACKGROUND

Radiation therapy is an effective approach in the treatment of highly radiosensitive brain tumors such as germinomas. However, recent studies have reported intellectual disturbances in patients who underwent whole-brain irradiation as children. We detected apoptosis in the infantile murine cerebrum after systemic X-ray irradiation.

METHODS

Subjects were 100 ICR mice 4 weeks old, of which 90 were systemically exposed to 18 Gy X-rays (0.45 Gy/min); 10 each were decapitated and the cerebrums were removed 1, 3, 6, 9, 12, 18, 24, 48, and 72 hours after irradiation. Controls were 10 unirradiated mice. DNA fragmentation analysis was carried out by agarose gel electrophoresis, and morphological analysis was by the TUNEL method.

RESULTS

According to agarose gel electrophoresis, the cerebral DNA ladders were detected only over 6 to 24 hr, peaking in 9 hr. Even at the peak, band intensity was nearly double that of the unirradiated normal thymus. According to the TUNEL analysis, radiation-induced apoptosis increased, with a peak at 9 hours, but decreased 24 hours after irradiation. Apoptotic cells were always localized exclusively in the hippocampal dentate granule cells.

CONCLUSIONS

We found that vulnerability to radiation existed in the hippocampal dentate granule cells. Intellectual disturbances in patients who have undergone whole-brain irradiation may be caused by injury to the hippocampus.

Schedule-dependent interactions between raltitrexed and cisplatin in human carcinoma cell lines in vitro

Raltitrexed ('Tomudex') is a new anticancer agent which inhibits thymidylate synthase. To provide a rational basis for clinical trial design of the combination of raltitrexed and cisplatin, we studied the cytotoxic effects of this combination using various schedules in vitro and four human colon cancer cell lines, Colo201, Colo320, LoVo, and WiDr. Cell growth inhibition after 5 days was determined by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The effects of drug combinations at the concentration producing 80% cell growth inhibition (IC(80)) level were analyzed by the isobologram method. Simultaneous exposure to raltitrexed and cisplatin for 24 h, and sequential exposure to raltitrexed followed by cisplatin produced additive effects in the Colo201, Colo320, and LoVo cells, and additive and synergistic effects in WiDr cells. Sequential exposure to cisplatin followed by raltitrexed produced additive effects in the Colo201 cells and antagonistic effects in other three cell lines. Simultaneous and continuous exposure to both agents for 5 days produced additive effects in all four cell lines. These findings suggest that the simultaneous administration of raltitrexed and cisplatin, or the sequential administration of raltitrexed followed by cisplatin, generally produce the expected cytotoxicity at the cellular level and are optimal schedules, while the sequential administration of cisplatin followed by raltitrexed produces antagonistic effects and is inappropriate for this combination. Further in vivo and clinical studies will be necessary to determine the toxicity and antitumor effects of this schedule.

Diminished expression of CD59 on activated CD8+ T cells undergoing apoptosis in systemic lupus erythematosus and Sjögren's syndrome

The present study was undertaken to examine the phenotype of T cells undergoing in vitro apoptosis in patients with autoimmune diseases such as systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (SS). Compared with normal controls, we found diminished expression of CD59 antigen (one of the cell-surface complement-regulatory proteins) on CD8+ T cells, but not on CD4+ T cells, from patients with SLE and SS. Three-colour immunofluorescence analysis revealed that these CD59dim CD8+ T cells were activated T cells, expressing both human leucocyte antigen (HLA)-DR and CD45RO antigens. In addition, these CD59dim CD8+ T cells were more susceptible to in vitro apoptosis than CD59bright CD8+ T cells. In two patients with active lupus, the percentage of CD59dim CD8+ T cells was significantly decreased after steroid therapy. These findings suggest that decreased expression of CD59 antigen on in vivo-activated CD8+ T cells may be correlated with disease activity and may be involved in activation-induced apoptosis in patients with SLE and SS.

In vitro cytotoxic effects of fludarabine (2-F-ara-A) in combination with commonly used antileukemic agents by isobologram analysis

Fludarabine phosphate (2-F-ara-AMP) is an adenine nucleoside analogue that shows significant activity against chronic lymphocytic leukemia and indolent lymphoma. We assessed the cytotoxic interaction produced by the combination of the active metabolite of fludarabine phosphate, fludarabine (9-beta-D-arabinofuranosyl-2-fluoroadenine, 2-F-ara-A), and some commonly used antileukemic agents against human hairy cell leukemia cell line JOK-1, human chronic lymphocytic leukemia cell line SKW-3, and adult T cell leukemia cell lines ED-40810 (-) and SALT-3. The leukemia cells were exposed simultaneously to 2-F-ara-A and to the other agents for 4 days. Cell growth inhibition was determined using MTT reduction assay. The isobologram method of Steel and Peckham was used to evaluate the cytotoxic interaction. 2-F-ara-A and cytarabine showed synergistic effects in SKW-3 cells, additive and synergistic effects in JOK-1 and SALT-3 cells, and additive effects in ED-40810(-) cells. 2-F-ara-A and doxorubicin showed additive effects in SKW-3, ED-40810(-) and SALT-3 cell lines, and additive and synergistic effects in JOK-1 cells. 2-F-ara-A showed additive effects with etoposide, 4-hydroperoxy-cyclophosphamide, and hydroxyurea in all four cell lines. 2-F-ara-A showed antagonistic effects with methotrexate and vincristine in all four cell lines. Our findings suggest that the simultaneous administration of fludarabine phosphate with cytarabine, doxorubicin, etoposide, cyclophosphamide, or hydroxyurea would be advantageous for cytotoxic effects. Among these agents, cytarabine may be the best agent for the combination with fludarabine phosphate. The simultaneous administration of fludarabine phosphate with methotrexate or vincristine would have little cytotoxic effect, and this combination may be inappropriate. These findings may be useful in clinical trials of combination chemotherapy with fludarabine phosphate and these agents.

[Targeting therapy using a monoclonal antibody against tumor vascular endothelium]

Recent studies have revealed that the targeting therapy using monoclonal antibody against tumor associated antigens did not have a clinically satisfactory effect due to various physiological characters of tumor. We propose a novel approach targeting tumor vascular endothelium to solve the inefficiency of common tumor missile therapy. In this study, the tissue distribution of anti-tumor vascular endothelium monoclonal antibody (TES-23) produced by immunizing with plasma membrane vesicles obtained from isolated rat tumor-derived endothelial cells (TECs) was assessed in various tumor-bearing animals. Radiolabeled TES-23 dramatically accumulated in KMT-17 fibrosarcoma, a source of isolated TECs after intravenous injection. In Meth-A fibrosarcoma, Colon-26 adenocarcinoma in BALB/c mice and HT-1080 human tumor tissue in nude mice, radioactivities of 125I-TES-23 were also up to fifty times higher than those of control antibody with little distribution to normal tissues. Furthermore, immunostaining of human tissue sections showed specific binding of TES-23 on endothelium in esophagus and colon cancers. These results indicate that tumor vascular endothelial cells express a common antigen in different tumor types of various animal species. In order to clarify the efficacy of TES-23 as a drug carrier, an immunoconjugate, composed of TES-23 and neocarzinostatin, was tested for its antitumor effect in vivo. The immunoconjugate (TES-23-NCS) caused a marked regression of the tumor, KMT-17 in rats and Meth-A in mice. Thus, from a clinical view, TES-23 would be a novel drug carrier because of its high specificity to tumor vascular endothelium and its application to many types of cancer.

In vitro remodeling of tumor vascular endothelial cells using conditioned medium from various tumor cells and their sensitivity to TNF-alpha

Prevention of tumor-associated blood vessel formation (angiogenesis) is a potentially powerful strategy to treat cancer. We found that tumor vascular endothelial cells were rearranged in vitro with conditioned culture medium derived from tumor cells and compared the sensitivity to the effects of TNF-alpha between normal and tumor endothelial cells. Incubation with tumor (Meth-A, Colon26)-derived conditioned medium showed that no effect was observed on cell growth. Tumor cells (Meth-A, Colon26, and B16BL6) only showed no sensitivity to TNF-alpha. Normal and control endothelial cells in culture showed little cytotoxicity in response to TNF-alpha treatment, but marked cytotoxicity of TNF-alpha was observed in endothelial cells cultured with tumor-derived conditioned medium. Sensitivity to TNF-alpha was different depending on the type of tumor from which the conditioned medium was derived. This difference in sensitivity was assumed to be due to the in vivo sensitivity to TNF-alpha. The results of this study suggested that the sensitivity of tumors to TNF-alpha is controlled by the sensitivity of tumor vasculature.

Analysis of prognostic and survival factors related to treatment of low-grade astrocytomas in adults

Prognostic factors for low-grade astrocytomas have been proposed, but optimal treatment remains controversial. Eighty-eight consecutive adult patients with supratentorial low-grade astrocytomas were retrospectively reviewed to determine specific factors influencing outcome. All underwent craniotomy (43 radical resections, 45 nonradical resections). Sex, age at diagnosis, preoperative Karnofsky performance status (KPS), tumor location, estimated extent of resection, radiation, chemotherapy, histological type, p53 status, MIB-1 staining and the apoptotic index were assessed as parameters for prognostic significance. KPS (p = 0.03), tumor location (p < 0.001), extent of surgical resection (p < 0.001) and radiotherapy (p = 0.01) were significantly associated with longer survival rates by univariate analysis. Multivariate analysis also showed a significant correlation between radiation therapy after surgical removal and survival time (p < 0.001). p53 status was not of importance in determining the necessity for radiotherapy. Radical surgical removal is the most important factor in the management of low-grade astrocytomas. Radiation therapy appears to be effective in improving the prognosis regardless of the extent of surgical resection or the p53 status.

Preferential activity of wild-type and mutant tumor necrosis factor-alpha against tumor-derived endothelial-like cells

Tumor-derived endothelial-like cells (tEC) were prepared by culturing human umbilical vein endothelial cells (HUVEC) in the presence of HT1080 human fibrosarcoma-conditioned medium. tEC showed higher permeability and less cell-adhesion activity than normal HUVEC (nEC). Tumor necrosis factor-alpha (TNF) is known to have tumor-vasculature disrupting activity. tEC showed higher cytotoxicity to recombinant human TNF (rhTNF) than nEC, and was not observed using HUVEC cultured with WI38 human diploid cell-conditioned medium as a medium-control. These results demonstrate that tEC acquire physiological properties of tumor-associated vasculature, and may be a useful model system for the study of the mechanisms of TNF antitumor action. The TNF-mutant RGD-V29 (code No. F4614), which has an inserted 4Arg-Gly-Asp sequence and an 29Arg-->Val replacement, was found to induce greater preferential destruction of tEC compared to rhTNF. When the preferential activities were evaluated in terms of 30% cytotoxicity (IC30) ratio (nEC/tEC), the ratio was 460 for RGD-V29 compared to 4.2 for rhTNF. RGD-V29 also exhibited cell-adhesive function and bound preferentially to the p55 TNF-receptor. Both these properties of RGD-V29 contributed to the tEC selective cytotoxicity, indicating that the RGD ligands and selective p55 receptor binding on the cells, although uncharacterized, are involved in tEC targeting. Therefore, the TNF mutant RGD-V29 may show greater selectivity toward tumor vasculature than wild-type TNF.

Specific binding of TES-23 antibody to tumour vascular endothelium in mice, rats and human cancer tissue: a novel drug carrier for cancer targeting therapy

The tissue distribution of anti-tumour vascular endothelium monoclonal antibody (TES-23) produced by immunizing with plasma membrane vesicles from isolated rat tumour-derived endothelial cells (TECs) was assessed in various tumour-bearing animals. Radiolabelled TES-23 dramatically accumulated in KMT-17 fibrosarcoma, the source of isolated TECs after intravenous injection. In Meth-A fibrosarcoma, Colon-26 adenocarcinoma in BALB/c mice and HT-1080 human tumour tissue in nude mice, radioactivities of 125I-labelled TES-23 were also up to 50 times higher than those of control antibody with little distribution to normal tissues. The selective recognition of TES-23 to TECs was competitively blocked by preadministration of unlabelled TES-23 in vivo. Furthermore, immunostaining of human tissue sections showed specific binding of TES-23 on endothelium in oesophagus cancers. These results indicate that tumour vascular endothelial cells express common antigen in different tumour types of various animal species. In order to clarify the efficacy of TES-23 as a drug carrier, an immunoconjugate, composed of TES-23 and neocarzinostatin, was tested for its anti-tumour effect in rats bearing KMT-17 fibrosarcomas. The immunoconjugate (TES-23-NCS) caused marked regression of the tumour, accompanied by haemorrhagic necrosis. Thus, from a clinical view, TES-23 would be a novel drug carrier because of its high specificity to tumour vascular endothelium and its application to many types of cancer.

The organization of INAD-signaling complexes by a multivalent PDZ domain protein in Drosophila photoreceptor cells ensures sensitivity and speed of signaling

Phototransduction in Drosophila has emerged as an attractive model system for studying the organization of signaling cascades in vivo. In photoreceptor neurons, the multivalent PDZ protein INAD serves as a scaffold to assemble different components of the phototransduction pathway, including the effector PLC, the light-activated ion channel TRP, and a protein kinase C involved in deactivation of the light response. INAD is required for organizing and maintaining signaling complexes in the rhabdomeres of photoreceptors. This macromolecular organization endows photoreceptors with many of their signaling properties, including high sensitivity, fast activation and deactivation kinetics, and exquisite feedback regulation by small localized changes in [Ca2+]i. Assembly of transduction components into signaling complexes is also an important cellular strategy for ensuring specificity of signaling while minimizing unwanted cross-talk. In this report, we review INAD's role as a signal transduction scaffold and its role in the assembly and localization of photoreceptor complexes.

[A case of neuroleptic malignant syndrome associated with reversible leukoencephalopathy]

We report a case of neuroleptic malignant syndrome associated with reversible leukoencephalopathy. The patient was a 60-year-old woman. Soon after ingesting an antipsychotic drug, the patient developed neuroleptic symptoms. After hydration and dantrolene sodium were administered, muscular rigidity gradually improved and serum levels of CK became normal. On the 7th hospital day, however, she fell into coma and showed tetraplegia. Although brain CT was normal on admission, diffuse low density areas were observed on the parieto-occipital cerebral white matter. The same lesions were observed on T2-weighted MRI. On the 20th hospital day, after giving her glycerol and adrenocorticosteroid, not only abnormal neurological findings but also abnormal CT and MRI findings disappeared. There were only two case reports of leukoencephalopathy with malignant syndrome in the literature. This is a rare case of reversible leukoencephalopathy with neuroleptic malignant syndrome due to the antipsychotic drug.

Frontal midline theta rhythms reflect alternative activation of prefrontal cortex and anterior cingulate cortex in humans

Frontal midline theta rhythm (Fm theta) often appears on electroencephalogram (EEG) during consecutive mental tasks. To clarify the source of rhythmic activity, magnetoencephalogram (MEG) and EEG were simultaneously measured in six healthy volunteers during different mental tasks using whole head MEG system. MEG records were averaged every one cycle of Fm theta rhythms using individual positive peaks of Fm theta waves in Fz EEG as a trigger. Averaged theta components of MEG signals were analyzed with a multi-dipole model. Two sources were estimated to the regions both of the prefrontal-medial superficial cortex and anterior cingulate cortex (ACC). These regions were alternatively activated in about 40 to 120 degrees phase shift during one Fm theta cycle. From above results, we hypothesize that appearance of Fm theta during consecutive mental tasks reflects alternative activities of the medial prefrontal cortex and ACC.

Muscle sympathetic activity in cerebellar degeneration with or without mild autonomic dysfunction

To evaluate autonomic function in sporadic cases of cerebellar degeneration (CD) with or without mild autonomic dysfunction, we measured muscle sympathetic nerve activity (MSNA) by microneurography in 12 CD patients and 18 healthy subjects. The burst incidence and mean amplitude of MSNA at rest was significantly decreased in CD patients (P < 0.01). There were no significant differences between patients with CD and controls in heart rate or blood pressure at rest. During head-up tilting, increases in blood pressure and mean amplitude of MSNA were significantly lower in CD patients. In conclusion, a decrease in muscle sympathetic outflow can be observed even in CD patients who are clinically excluded from multiple system atrophy (MSA). It might be difficult to distinguish other CD syndromes from MSA in recordings of muscle sympathetic activity.

Schedule-dependent interactions between paclitaxel and etoposide in human carcinoma cell lines in vitro

Clinical studies of paclitaxel in combination with etoposide against solid tumors have been carried out. The combination schedules used in these studies are different. We studied the cytotoxic effects of paclitaxel with etoposide against four human cancer cell lines in vitro to determine the optimal schedule of this combination at the cellular level. Cells were exposed simultaneously to paclitaxel and to etoposide for 24 h or sequentially to one drug for 24 h followed by the other for 24 h, after which they were incubated in drug-free medium for 4 and 3 days, respectively. Cell growth inhibition was determined by an MTT reduction assay. The effects of drug combinations at concentrations producing 80% inhibition (IC(80)) were analyzed by the isobologram method of Steel and Peckham. The cytotoxic effect of paclitaxel and etoposide was cell line- and schedule-dependent. Simultaneous exposure to paclitaxel and etoposide for 24 h produced additive effects in the lung cancer cell line A549 and ovarian cancer PA1 cells, and antagonistic effects in the breast cancer cell line MCF7 and colon cancer WIDr cells. Sequential exposures to paclitaxel followed by etoposide and vice versa produced additive effects in all four cell lines. These results suggest that maximum cytotoxic effects can be obtained with sequential administration, but not simultaneous administration, of paclitaxel and etoposide. These findings may have important clinical implications for this combination.

Suppression of solid tumor growth by a monoclonal antibody against tumor vasculature in rats: involvement of intravascular thrombosis and fibrinogenesis

We have reported that immunization of rat tumor-derived endothelial cells (TEC) isolated from KMT-17 solid tumors results in the generation of several monoclonal antibodies (MAbs). TES-23, one of these MAbs, recognizes a naturally occurring 80-kDa antigen expressed on endothelial cells of tumor blood vessels. To determine whether such MAbs can suppress solid tumor growth in vivo by impairment of endothelial cells in tumors following direct binding, we tested the biodistribution of (125)I-labeled TES-23 in rats bearing KMT-17 solid tumors. We also examined the effect of treatment using unconjugated TES-23 on tumor growth and histo-pathological changes in tumor tissues. Biodistribution studies showed localization of TES-23 into tumor tissues 60 min after intravenous injection. TES-23 suppressed significantly the growth of KMT-17 solid tumors following administration for 5 days. Histo-pathological examination showed that TES-23 caused degeneration, apoptosis and/or necrosis and denudation of endothelial cells in viable tumor areas following local aggregation and adhesion of lymphocytes, with subsequent intravascular thrombus formation by platelets and fibrin. Our results indicate that TES-23, which recognizes TEC, can target endothelial cells of solid tumor vasculature directly, resulting in growth suppression in vivo by reduction of blood flow due to intravascular thrombosis. Our results also suggest that targeting tumor vasculature is a potentially attractive approach for the treatment of solid tumors.

Genomic alterations in human meningiomas detected by restriction landmark genomic scanning and immunohistochemical studies

Using restriction landmark genomic scanning (RLGS) methods, 21 samples of human meningioma were analyzed. We found 3 alterations in the genomic DNAs of tumor samples located on chromosomes 5, 14 and 17 which appear to be common to the meningothelial subtype. Two other separate genetic abnormalities located on chromosomes 9-12 and 20 are apparently associated with atypical meningiomas. In addition, the neurofibromatosis type 2 gene is apparently involved in more than half of the tumor samples. There appear to be both common and type-specific genetic mutations associated with the formation and progression of human meningiomas.