Biomedical subjects

G Soma

Publications and source records attributed to G Soma.

At least 73 records · Page 4Linked to original sources

PubMed1985

Structural analysis of a developmentally regulated 25-kDa protein gene of Sarcophaga peregrina.

In the previous paper, we described the identification of two abundant mRNAs of Sarcophaga peregrina (flesh-fly) which are selectively expressed in the fat body of middle third instar larvae. One of these mRNAs was found to encode a protein with a molecular mass of about 25,000 (25-kDa protein) when translated in vitro (Tamura, H., et al. (1983) Dev. Biol. 99, 145-151). Present paper reports the nucleotide sequence of a 2.3 kb DNA containing the entire gene for the 25-kDa protein. This gene consisted of four exons and contained an open reading frame for 184 amino acids. A CAT box and a TATA box were found in the 5'-flanking sequence. A poly A addition signal of AATAAA was assigned to the non-coding region in the fourth exon. A sequence having 75% homology with SV40 enhancer core sequence was identified in the non-coding region of the first exon.

Adipose Tissue↗

PubMed1984

Molecular cloning and characterization of a cDNA clone for a protein specifically expressed in embryo as well as in a chemically induced pancreatic B cell tumor of rat.

cDNAs were molecularly cloned for proteins specifically expressed in embryo as well as in a chemically induced rat pancreatic B cell tumor in which virally related oncogenes such as v-myc, v-src, v-yes, v-mos and v-kis were previously demonstrated not to be expressed. A plasmid cDNA library consisting of 48,000 independent colonies was constructed from poly(A) containing cytoplasmic RNA isolated from 12 day rat embryo. The library was screened by hybridization with 32p-labelled cDNA synthesized from poly(A) containing RNA of rat pancreatic B cell tumor or normal islet B cells. Two clones were obtained which showed a clearly positive reaction only with tumor probe. Nucleotide sequence of one of them harboring insert of 615 nucleotides was determined and its amino acid sequence of 119 residues was deduced, which showed that the protein encoded by this mRNA is highly basic, basic residues/acidic residues being 1.63.

Adenoma, Islet Cell↗

PubMed1984

Heterogeneity of 3' nontranslated regions in proopiomelanocortin (POMC) precursor mRNA of chum salmon Onchorynchus keta: polymorphism of the gene.

Heterogeneity of salmon pituitary proopiomelanocortin (POMC) mRNA was shown by comparison of the nucleotide sequence of independently isolated cDNA clones encoding POMC, pSSM90, pSSM53 and pSSM17, the last of which was previously characterized. Newly isolated clones pSSM90 and pSSM53 contained inserts of 1228 and 666 base pairs, respectively (excluding poly(A)). Sequence analysis revealed that the former contained sequences coding for the carboxy half of putative corticotropin (ACTH), the whole region of beta-lipotropin (beta-LPH), and the entire 3' nontranslated region, while the latter contained only the 3' nontranslated region. Sequence comparison of the three clones revealed that there are some definite nucleotide changes in the 3' nontranslated regions, i.e., base replacements and base additions at multiple sites, whereas no single change was observed in the coding regions, thus demonstrating heterogeneity and hence polymorphism of the gene in the salmon genome.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Correlation of the expression of nuclear factor-kappa B, tumor necrosis factor receptor type 1 (TNFR 1) and c-Myc with the clinical course in the treatment of malignant astrocytomas with recombinant mutant human tumor necrosis factor-alpha (TNF-SAM2).

We present our experience with a combination chemotherapy regimen consisting of ranimustine (MCNU) and recombinant human mutant tumor necrosis factor-alpha (TNF-SAM2) for malignant astrocytomas. We also investigated the expression of nuclear factor-kappa B (NF-kappa B), tumor necrosis factor receptor type 1 (TNFR1), and c-Myc in human astrocytoma tissues in vivo in patients treated with TNF-SAM2 by RT-PCR and immunohistochemical analysis to examine whether there is any correlation between the prognosis of these patients after TNF-SAM2 treatment and the expression of these factors. The initial regimens were prescribed as adjuvant therapy in conjunction with radiotherapy following standard surgical treatment. Newly diagnosed patients were treated with up to four cycles of this regimen (TNF-SAM2, MCNU, and radiotherapy: TMR group). Four patients with anaplastic astrocytomas and 13 patients with glioblastomas (11 men and 6 women) aged 24 to 68 years (median 55.7 years) were eligible and evaluated for response and toxicity. The estimated median survival time was 354 weeks with anaplastic astrocytomas, and 79 +/- 10.8 weeks with glioblastomas. One- and 2-year survival rates were 100% and 100% with anaplastic astrocytomas, and 69.2% and 30.8% with glioblastomas. Grade 3 and 4 hematological toxicities were not experienced. None of the patients experienced a treatment delay due to toxicity. All other acute toxicities were anticipated and manageable. Two of the 4 patients with anaplastic astrocytomas were positive for the expression of NF-kappa B, TNFRl and c-Myc. The expression of NF-kappa B, TNFR1 and c-Myc was investigated in 10 of the 13 patients with glioblastoma, and c-Myc, TNFRl and NF-kappa B were detected in 9, 7, and 8 of these 10 patients' surgical specimens, respectively. Despite the small number of patients, these clinical results suggest that combined chemotherapy with mutant TNF-alpha (TNF-SAM2) was safe and well tolerated, and may confer a survival benefit for patients with malignant astrocytomas in comparison to our historical controls. Its effectiveness as an adjuvant therapy deserves a properly stratified randomized trial. Although there was no significant correlation between the efficacy of TNF-SAM2 treatment and the expression of NF-kappa B, our results suggest that the constitutive activation of NF-kappa B subunits in malignant astrocytomas, especially in glioblastoma, could be associated with resistance to TNF-alpha immunotherapy. These results could offer new insight to help establish a new chemotherapeutic strategy for malignant astrocytomas.

Adult↗

PubMedDate not supplied

Pharmacokinetics of isolated hepatic perfusion with high dose tumor necrosis factor in rat model.

BACKGROUND: Although the application of an isolation procedure with tumor necrosis factor (TNF) to the liver is quite attractive, an animal model is not yet available to evaluate antitumor effects by TNF in isolated hepatic perfusion (IHP). To establish the rat model in IHP, the pharmacokinetics of TNF, both in a perfusate and in a systemic circuit should be examined. METHODS: All rats underwent IHP with TNF. After a 10 min perfusion, a washout procedure was performed for 5 min, after which isolation was terminated. Throughout the procedure and afterward, blood samples were obtained from the systemic blood and concentrations of TNF were assayed by L-929 cytotoxicity. RESULTS: After the administration of 240 micrograms of TNF in the circuit, TNF reached a plateau at about 12.7 micrograms/ml of perfusion fluid, lasting until the end of IHP. As a result of the washout procedure, regional TNF concentrations declined from 12.7 micrograms/ml to 1.5 micrograms/ml. At the beginning of the IHP, all rats exhibited no detectable level of TNF activity in the systemic circulation (< 100 pg/ml). With time, TNF plasma levels quickly increased to reach a plateau of about 0.2 microgram/ml at 15 min. Systemic leakage of TNF is calculated as less than 2% of the total TNF in perfusate during perfusion. CONCLUSION: Rat IHP models with TNF showed that systemic leakage of TNF was higher than that of pig models, although a large enough amount of TNF in perfusate was achieved without death. Rat models might be feasible to evaluate antitumor effect of IHP against liver metastatic tumors.

Animals↗

PubMedDate not supplied

Reduction of hepatotoxicity of tumor necrosis factor in isolated hepatic perfusion by administration of glucocorticoid as well as lipopolysaccharide.

BACKGROUND: The application of an isolation procedure with tumor necrosis factor (TNF) to the liver is quit attractive, however, one of problems to overcome is reducing the toxicity to the liver caused by high doses of TNF. MATERIALS AND METHODS: Rats underwent isolated hepatic perfusion (IHP) with TNF and pre-treatment of subcutaneous administration of dexamethasone (4 mg/kg) and/or intradermal administration of LPS (50 micrograms/rat). After a 10 min perfusion, a washout procedure was performed for 5 min, after which isolation was terminated. RESULTS: SD or Wister rats and F344 rats tolerated up to 120 mg/rat or 4 micrograms/rat, respectively. Dexamethasone and/or LPS was tolerated at 40 micrograms/rat of TNF in F344 rat and showed a significant reduction of hepatotoxicity, and indicated histologically the suppression of ballooning and of necrosis during and after perfusion by TNF. CONCLUSION: We propose new a protocol for IHP as follows: 1. the intradermal administration of LPS for protection against toxicity of TNF, 2. IHP with TNF-SAM2, a mutain of TNF-alpha, having less toxicity than conventional TNF-alpha, and 3. simultaneous perfusion with chemotherapeutic agents such as 5-fluorouracil (5-FU).

Adult↗

PubMedDate not supplied

Relationship between microvessel quantification and inducibility of endogenous tumor necrosis factor in colorectal adenocarcinoma.

BACKGROUND: Although we have reported that the inducibility of endogenous tumor necrosis factor (en-TNF) by tumor cells is an independent prognostic factor in Dukes stage C colorectal cancer patients, the mechanism by which the patients having high inducibility of en-TNF show better prognosis is still unclear. We hypothesize that the inducibility of en-TNF by colorectal tumor cells affects the prognosis of patients through the modulation of angiogenesis. Thus, the aim of this study is to clarify the relationship between inducibility of en-TNF and tumor vascularity in colorectal cancer. PATIENTS AND METHODS: Histological sections from 62 Dukes stage C colorectal cancer patients who received curative operation were immunostained for CD34 antigen. Microvessels were counted in the photograph of x200 fields (0.298 mm2). The average count of five most vascular areas was determined as a microvessel density of each case. RESULTS: Two of 62 cases were excluded from the analysis, because of insufficient staining. A total of 60 patients were dichotomized by a median vessel count of 34 into two groups: 30 patients with lower microvessel density (Low MVD group) and 30 patients with higher microvessel density (High MVD group). There was no significance in the distribution of all clinicopathological factors among these two groups. Regarding en-TNF inducibility, no difference was shown between the two groups. The five year survival rate of Low MVD group and High MVD group were 58.7% and 68.0%, respectively. And, the 5 year relapse-free survival rate of Low MVD group and High MVD group were 59.7% and 52.2%, respectively. No significant difference was demonstrated between Low MVD group and High MVD group. CONCLUSION: Intratumoral microvessel density did not influence on the prognosis of colorectal cancer patients in Dukes stage C after curative operation. The inducibility of en-TNF showed no correlation with intratumoral microvessel density in Dukes stage C patients after curative operation.

Adenocarcinoma↗

PubMedDate not supplied

Synergistic antitumour effect of TNF-SAM2 with melphalan and doxorubicin in isolated limb perfusion in rats.

An isolated limb perfusion model (ILP) using soft tissue sarcoma bearing rats (BN175) was used to study antitumour activity of a tumour necrosis factor alpha mutant (TNF-SAM2) in combination with melphalan and doxorubicin. Progressive disease was demonstrated after ILP without agents (sham) or with 50 micrograms TNF-SAM2. ILP with 40 micrograms melphalan or 400 micrograms doxorubicin resulted in no change of tumour volume or progressive disease five days after perfusion. Partial and complete response rates were demonstrated in 76% of rats when the combination of TNF-SAM2 and melphalan was used. TNF-SAM2 in combination with doxorubicin was synergistic as well with a 70% response rate. Histopathologically these responses consisted of hemorrhagic necrosis of the coagulative type. 2 In conclusion, TNF-SAM2 has similar antitumour activity in combination with melphalan or doxorubicin as rHuTNF in sarcoma-bearing rats and is eligible to be tested in clinical ILP or organ perfusion settings because of its potential decreased toxicity.

Animals↗

PubMedDate not supplied

Clinical significance of the expression of endothelial-monocyte activating polypeptide II (EMAPII) in the treatment of glioblastoma with recombinant mutant human tumor necrosis factor-alpha (TNF-SAM2).

BACKGROUND: The application of human mutant recombinant TNF-alpha (TNF-SAM2) to glioblastoma has shown that there is marked variation in its sensitivity to TNF. To determine whether the production of endothelial-monocyte activating polypeptide II (EMAPII) by tumors confers TNF sensitivity and whether EMAPII expression in glioblastoma can predict the clinical response to TNF therapy, we evaluated EMAPII expression and the efficacy of TNF in patients with glioblastoma. MATERIALS AND METHODS: We analyzed EMAPII mRNA expression using reverse transcriptase-polymerase chain reaction (RT-PCR) of frozen tissue sections of glioblastoma and evaluated if there was any correlation between EMAPII expression and the response to TNF therapy in patients with glioblastoma. RESULTS: Amplified bands corresponding to EMAPII were obtained by RT-PCR in 8 out of 11 glioblastomas. There was a significant correlation between the time to tumor progression after TNF-SAM2 treatment and the expression of EMAPII (p < 0.05). Patients with positive expression of EMAPII in their tumor tissues tended to have longer progression-free survival. CONCLUSION: Variable responses to combined chemotherapy with mutant TNF-alpha (TNF-SAM2) might be explained by EMAPII expression in glioblastoma. EMAPII expression in glioblastoma might predict the clinical response to TNF therapy and potentially identify patients with cytokine-responsive tumors.

Aged↗

PubMedDate not supplied

A new method of antitumor therapy with a high dose of TNF perfusion for unresectable liver tumors.

There are primary and secondary malignant liver tumors for which principal treatment is surgical resection. There is no established treatment for unresectable malignant liver tumors, however, and the prognosis for these is quite poor. An effective treatment for malignant liver tumors is thus urgently needed. Recent advances in molecular biology have uncovered the structures and/or functions of many cytokines thought to have a strong relation with the mechanisms of the antitumor effect of biological therapies. Availability of those cytokines in large amounts and homogeneously owing to advances in recombinant technology makes it possible to use them clinically. Among cytokines demonstrating antitumor activities, tumor necrosis factor-alpha (TNF-alpha) is one of the strongest. However, severe toxicity such as hypotension, abnormalities in liver function, leukopenia, chill and thrombus formation makes TNF-alpha difficult to use systemically as an antitumor drug. To enhance cytotoxicity while decreasing the side effects, especially hypotension, we developed a mutein called TNF-SAM2 by protein-engineering. The biological activity of TNF-SAM2 was more beneficial than TNF-alpha for antitumor therapy, since its side effects were milder. In contrast, using the isolated limb perfusion (ILP) method against malignant melanoma and soft tissue sarcoma of the extremities in combination with TNF-alpha and melphalan, a high response rate of 70-100% was observed. These observations led to the re-evaluation of TNF as an antitumor drug. A preliminary clinical trial was done using TNF-alpha combined with the formation of a closed circuit (isolated hepatic perfusion method) targeting the liver and a response rate of over 75% was achieved against malignant liver tumors. To isolate the liver from the systemic circulation, however, required a laparotomy, so that patients were subjected to excessive surgical stress. Isolated hypoxic hepatic perfusion (IHHP) using balloon catheters is a treatment developed to overcome such stress and we are planning to do clinical trials of IHHP with TNF-SAM2 in combination with a chemotherapeutic agent against malignant liver tumor patients. IHHP combined with TNF-SAM2 and a chemotherapeutic agent might be more beneficial in antitumor effects as well as in maintaining good quality of life (QOL) for the patient.

Animals↗

PubMedDate not supplied

Activation of the systemic production of tumor necrosis factor after exposure to acute stress.

Tumor necrosis factor (TNF), which was originally identified as a tumoricidal factor, is now regarded as one of the main regulators of inflammation and various immune systems. Thus it has been considered to be mobilized in case of emergency. However, we assume that TNF and the cytokine network driven by the monokine also function under normal condition for homeostasis of the animal body which is exposed to various kinds of physiological stress. To test this possibility, we exposed C3H/He mice for up to 3 days to five types of acute stress: food deprivation, drinking water deprivation, sleep deprivation, swimming, and physical restraint. After release from the stress, the level of priming for systemic production of TNF was examined using OK-432 (a streptococcal preparation) as a trigger. Priming of TNF production was not observed immediately after 2-day exposure to most of the stressors. Sleep deprivation alone tended to induce a primed state especially when the stress period was lengthened to 3 days. On the other hand, by keeping mice in a normal condition for a 2-day restorative interval after 2-day exposure to the stressors, systemic production of TNF was consistently primed for all the stress examined. The time course of the priming effect was examined in detail for water-deprivation stress. The effect was detected as early as 3 hours after release from stress, was sustained for 2 days, and returned to the basal level by 4 days after the release. Based on these results, we discussed the role of the TNF-driven cytokine circuit in adaptation to stress.

Adaptation, Physiological↗

PubMedDate not supplied

Inhibition of morphine dependence by a lipopolysaccharide from Pantoea agglomerans.

A lipopolysaccharide from Pantoea agglomerans (LPSp) was purified and examined for relief of morphine dependence by observing its inhibition of the jumping of mice on naloxone-precipitate withdrawal. Administration of LPSp either intravenously or intradermally showed marked inhibition of the jumping. Beta-endorphin in mouse serum and brain tissue were recognized to be in synchrony with the time course of the relief. Administration of TNF-alpha gave similar effect, suggesting that LPSp induces a cytokine cascade to produce endogenous TNF followed by ACTH/beta-LPH gene products and beta-endorphin. The effect of LPSp was better than that of LPS from E. coli or Bordetella pertussis, and thus is considered to be applicable for clinical use.

Animals↗

PubMedDate not supplied

Expression of tumor necrosis factor-alpha and -beta transcripts in embryonal carcinoma and trophoblast cell lines: inflammation-like state as possible regulatory mechanism for ontogenesis.

TNF-alpha and TNF-beta are both involved in inflammation which regulates homeostasis in adults. We examined the mRNA expression of TNF-alpha and TNF-beta in murine embryonal carcinoma (EC) cell lines (PCC3, PCC4, ECA2 and F9) and trophoblast cell line (PL/B6) using a combined system of reverse transcription and polymerase chain reaction. Four lines of EC cells and PL/B6 expressed mRNA of both TNFs. Moreover, mRNA expression of two types of TNF-receptor and transcription factor NF-kappa B, both of which mediate a part of the biological function of TNFs, were also detected in EC and trophoblast cells. In order to clarify whether other cytokines may form a network during embryonal development, we also examined the expression of transcripts of inflammatory cytokines produced by activated macrophages (IL-1 alpha, IL-1 beta and G-CSF) or by T lymphocytes (IL-3 and IFN-gamma) in adult. We found that no IL-1 alpha transcript was expressed in any of the cell lines examined whether differentiated or not. Contrary to this, the transcript of G-CSF was continuously expressed in all cell lines, and those of IL-1 beta, IL-3 and IFN-gamma were slightly expressed in some cell lines.

Animals↗

PubMedDate not supplied

Early embryonic cells activate the alternative complement system.

Murine embryonic stem cells, embryonic carcinoma cells and pre-implantation embryos were found to be extremely sensitive to cytolysis by normal human serum as compared to matured cells. The cytolytic activity to embryonic cells was not removed by pre-absorption of serum with spleen lymphocytes. Conditions which block both complement activation pathways or, selectively, the alternative pathway completely abrogated the activity of human serum against embryonic cells whereas the activity was retained under conditions which block the classical complement pathway, indicating that embryonic cells activate the alternative complement system (ACS). The cytotoxic effect to murine embryonic cells was reproduced using syngeneic murine serum. Concerning the mechanism of ACS-activation, the expression of regulators of complement activation and of membrane bound sialic acid was analysed. Embryonic cells express mRNA for Crry similarly to other cells but additionally express Cr2-transcripts not found in most adult cells. Embryonic cells have strikingly low levels of membrane-bound sialic acid compared to adult cells.

Animals↗

PubMedDate not supplied

Induction of differentiation in embryonic stem cells by 26-kD membrane-bound tumor necrosis factor (TNF) and 17-kD free TNF.

The biological activity of 26-kD membrane-bound tumor necrosis factor (TNF)-a in embryonal development was examined in an in vitro system using embryonic stem (ES) cells. ES cells were seeded on NIH3T3 feeder cells transformed with mouse precursor TNF-a gene to express membrane-bound TNF-a on their cell surface. The proliferation of the ES cells was reduced and differentiation was accelerated. The same effects were also observed when 17-kD free TNF-a was added to the culture medium of the ES cells. Since free TNF-a is not present during embryogenesis, these results suggest that membrane-bound TNF-a may play an important role in embryonal development through cell-cell contact.

3T3 Cells↗

PubMedDate not supplied

Selective lysis of early embryonic cells by the alternative pathway of complement--a possible mechanism for programmed cell death in embryogenesis.

Early embryonic cells and early mouse embryos were shown to activate the alternative pathway of complement, and to be highly sensitive to complement-mediated cytolysis (Kircheis et al, In Vivo 9: 85-98, 1995). Under further development embryonic cells become resistant. The induction of resistance to the alternative pathway of complement correlates with: a) altered splicing of Cr2-transcript and b) changes in the acidic glycolipids under differentiation. Early embryonic cells have low amounts of sialic acid-containing glycolipids or express mainly GM3. The induction of differentiation changes the glycolipid pattern leading to an increase in membrane-bound sialic acid. The importance of membrane-bound sialic acid in the restriction of complement activation is demonstrated by increased sensitivity to complement after pre-treatment of cells with neuraminidase. The results indicate that there is target-specific lysis of early embryonic cells by the alternative pathway of complement. Early embryonic cells activate the alternative pathway of complement by expressing activators and low levels of membrane-bound sialic acid. Induction of differentiation changes the glycolipid pattern, leading to an increase in membrane-bound sialic acid sufficient to restrict complement-activation on the cell surface.

Animals↗

PubMedDate not supplied

Induction of tumor necrosis factor by a camptothecin derivative, irinotecan, in mice and human mononuclear cells.

Irinotecan (CPT-11) has been reported to be cytotoxic to tumor cells through its inhibitory activity on type I DNA topoisomerase. CPT-11 has also been shown to have several unique biological activities apart from direct cytotoxicity. We investigated the ability of CPT-11 to induce tumor necrosis factor (TNF) production. Human peripheral blood mononuclear cells (MNCs) were incubated with LPS, CPT-11, or with vinblastin sulfate as a control. The priming effect of CPT-11 on endogenous production of TNF was examined by injecting the drug intravenously into mice, followed 3 hours by the injection of OK432. At a dose of 200-400 micrograms/kg, CPT-11 showed a significant priming effect. A significant amount of TNF was released when MNCs were incubated with 100-300 microM of CPT-11 for more than 4 hours, but not with vinblastin sulfate, indicating a triggering effect of TNF production on MNCs in vitro. These effects may be advantageous in cancer therapy.

Animals↗

PubMedDate not supplied

Augmentation of antitumor effect of endogenously induced tumor necrosis factor by cyclophosphamide.

The antitumor effect of endogenous tumor necrosis factor (en-TNF) with cyclophosphamide (CY) was analyzed using the murine Meth A tumor model. En-TNF was induced by the administration of interferon-gamma (4 micrograms/kg: 1 x 10(4) units/ mouse) as a primer and Streptococcus preparation OK-432 (100 KE/kg) as a trigger. Seven days after inoculation of Meth A tumor in BALB/c mice, about one third of LD50 of CY or five other chemotherapeutic agents (actinomycin D, mitomycin C, tegaful, adriamycin and puromycin) was injected intravenously. En-TNF was induced 7 days after administration of these agents. A combination therapy of en-TNF with CY showed the strongest antitumor effect among several combinations and caused complete tumor regression (40-70%), while none of the combinations with the other chemotherapeutics did so. The optimal time interval to obtain this antitumor effect with CY and en-TNF induction was 7 days. The amount of en-TNF induced around a tumor lesion with CY was two fold higher than that without CY. En-TNF was observed to be induced in tumor lesion solely by CY injection. All these results suggest that the antitumor effect of en-TNF can be augmented by addition of a chemotherapeutic agent such as CY.

Animals↗