Mechanisms of estrogen-associated carcinogenesis.
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Carcinogens↗
Biomedical subjects
T Tsutsui
Publications and source records attributed to T Tsutsui.
Administration of recombinant interleukin 12 prevents outgrowth of tumor cells metastasizing spontaneously to lung and lymph nodes.
The present study investigates the ability of recombinant interleukin 12 (rIL-12) to modulate the growth of a primary tumor as well as the outgrowth of metastatic tumor cells in an ovarian carcinoma (OV-HM) model. This aggressive tumor displayed rapid growth of the primary tumor mass, high incidence of metastases to lung and lymph nodes, and invasion from the primary s.c. site to the peritoneal cavity. Starting 12 days after s.c. tumor cell implantation, several i.p. injections of rIL-12 at 2-3 day intervals resulted in regression of growing tumors. These treated mice did not show signs of metastases or tumor recurrence at the original site. One month after tumor implantation, untreated mice did not have visible lung metastasis, but some did have palpable lymph nodes. At this stage, the primary tumors of animals without palpable lymph nodes were surgically resected. When examined 2 months later, most animals had developed lymph node and lung metastases. In contrast, rIL-12 injections after tumor resection inhibited the development of metastases in both lung and lymph nodes. This contrasted with the failure of IL-2 to prevent metastases. Even for mice already showing signs of lymph node metastases or invasion of the abdominal wall, rIL-12 administration after tumor resection prevented further invasion to the peritoneal cavity and growth of metastatic tumor cells in lung. It was somewhat surprising that the IL-12 treatment of animals after 1 month of tumor growth without resection also resulted in complete tumor regression, as well as eradication of micrometastasis that would have occurred before the treatment. Moreover, they exhibited resistance to a rechallenge with the same tumor but not with a second tumor. Thus, this tumor system provides a relevant model to clinical situations in terms of treatment of advanced tumors and metastases. These results also indicate that IL-12 can induce a curative immune response, even in the face of an aggressive micrometastasizing tumor.
Animals↗
Detection and characterization of apoptosis in osteoclasts in vitro.
Morphological changes of nuclei and DNA fragmentation undergoing cell death were studied using highly purified rabbit osteoclasts in vitro. Approximately fifty percent of dead osteoclasts exhibited morphological changes of nuclei characterized by apoptosis and approximately 70% of osteoclasts with changes of nuclei exhibited DNA fragmentation in our culture system. These changes of nuclei were confirmed as condensation of chromatin through transmission electronmicroscope. Moreover, biochemical characterizations of these changes were compatible with the characterizations of apoptosis in other cell systems. These results demonstrate that part of osteoclasts die by a mode of apoptosis.
Animals↗
Glomerular endothelial cells promote mesangial cell growth via a PDGF-Like substance.
We conducted these experiments to determine whether glomerular endothelial cells (GEN) may play a role in the regulation of glomerular mesangial cells (GMC) growth. When GMC were separately co-cultured with GEN for 24 h, [3H]thymidine incorporation into GMC increased by 22%. In addition, when GMC were co-cultured with GEN for 4 days, the GMC count increased statistically. Conditioned medium (CM) was obtained from confluent GEN monolayers and tested for its effect on GMC growth. When CM was mixed with RPMI 1640 medium containing fetal calf serum (final concentration: 10%), GMC growth was potentiated in a dose-dependent manner. This stimulatory effect of CM from GEN cultures was inhibited by the addition of anti-human platelet-derived growth factor (PDGF) antibody. However, antibodies against interleukin 1-beta, tumor necrosis factor-alpha and endothelin-1 did not affect the stimulatory effect of CM. Moreover, the modulator contained in CM was stable at 100 degrees C, and pH 2.5 at 22 degrees C for 30 min. When treated with 2 mM mercaptoethanol, this activity was almost completely lost. These findings suggest that GEN promote GMC growth in co-culture systems, without direct contact, by means of a PDGF-like substance.
Animals↗
Sodium fluoride-induced chromosome aberrations in different cell cycle stages.
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Chromosome Aberrations↗
No increases in chromosome aberrations in human diploid fibroblasts following exposure to low concentrations of sodium fluoride for long times.
To study whether exposure to fluoride at low concentrations for long times induces chromosome aberrations in human cells, human diploid fibroblasts in the quiescent phase were treated with sodium fluoride (NaF) at 1-10 micrograms/ml (equivalent to fluoride ion at 0.45-4.5 ppm) for 1-3 weeks. Quiescent cells were obtained by a 10-day culture in medium containing 1% serum following overnight incubation of cells in the logarithmic phase. Significant levels of cytotoxicity, as determined by a decrease in the number of cells, were not induced by treatment of the cells with NaF at 5 or 10 micrograms/ml for 1-3 weeks. No increase in the frequency of chromosome aberrations was elicited in cultures treated for 1-3 weeks with NaF over the range of doses examined. In contrast, a dose-dependent increase in the frequency of chromosome aberrations was observed in cultures treated with N-methyl-N'-nitro-N-nitrosoguanidine, used as a positive control. The results indicate that fluoride might be not clastogenic to human fibroblasts when exposed at low levels, equivalent to those in the communal water supplies.
Cells, Cultured↗
Cerebral blood flow distribution during induced hypotension with haemorrhage, trimetaphan or nitroprusside in rats.
Local cerebral blood flow (CBF) during three types of profound hypotension were compared using the quantitative autoradiographic [14]-C iodo-antipyrine method. Rats were rendered hypotensive to a mean arterial pressure of 30 mm Hg for 30 min by haemorrhage, trimetaphan or nitroprusside during 0.8% halothane anaesthesia. During haemorrhagic hypotension, mean local CBF was reduced significantly in all except two pontine regions. This reduction in flow ranged from 83% to 41% compared with the normotensive control group, with the neocortex and telencephalon most affected. During trimetaphan-induced hypotension, local CBF was reduced to the same degree and in the same pattern as that during haemorrhagic hypotension. In contrast, during nitroprusside-induced hypotension, local CBF in many regions of the brain was well maintained (57-101%); although local CBF was significantly below control in all cortical and telencephalic regions, it was significantly greater in the majority of these regions than in the other two hypotensive groups. We conclude that local CBF was significantly reduced in the neocortex and telencephalon by hypotension of this degree induced by all three methods, but nitroprusside preserved local CBF significantly better than the other methods, in these, as in most other regions.
Anesthesia, General↗
Aflatoxin B1-induced immortalization of cultured skin fibroblasts from a patient with Li-Fraumeni syndrome.
To examine the mechanisms of immortalization in human cells, normal human diploid fibroblasts (WHE-7) and skin fibroblasts from a patient with Li-Fraumeni syndrome (MDAH 087) and a mutant p53 allele were treated with aflatoxin B1 (AFB1). Exogenous metabolic activation of AFB1 with rat liver post-mitochondrial supernatant (PMS) was used and the optimal treatment conditions needed were determined by the inducibility of unscheduled DNA synthesis. The same degree of cytotoxicity was observed with MDAH 087 cells and normal WHE-7 cells treated with AFB1 at 0.1, 0.3 or 1 microgram/ml for 2 h with a 2% PMS mixture. All WHE-7 cell cultures (AFB1-treated and controls) failed to escape from senescence, whereas three out of nine AFB1-treated cultures of MDAH 087 cells escaped senescence. MDAH 087 cells treated with 0.1 microgram/ml of AFB1 two or three times initially decreased in growth approximately 40 days [10 population doublings (PD)] after the first treatment. However, the cells recovered with faster growth rates after approximately 100 additional days and grew continuously. Both cultures were immortal, defined as continuous growth for over 300 PD. Cells treated once with 0.3 microgram/ml of AFB1 also escaped senescence, although they had about a 230 day time lag before restoration of cell growth. The three AFB1-treated cell lines exhibited altered morphologies, chromosome aberrations (numerical and structural aberrations) and loss of the wild-type p53 allele. Although immortal, the cells were non-tumorigenic in nude mice. Spontaneous immortalization of untreated MDAH 087 was not observed in this study. The results indicate that AFB1 treatment of cells from a Li-Fraumeni patient, but not cells from normal individuals, can induce immortalization. This model may be useful for studying mechanisms of chemically induced immortalization.
Adult↗
Effects of testosterone, testosterone propionate, 17 beta-trenbolone and progesterone on cell transformation and mutagenesis in Syrian hamster embryo cells.
Testosterone, testosterone propionate, 17 beta-trenbolone and progesterone, which represent the main endogenous and synthetic androgens and a progestin, were evaluated for possible cell transformation and genetic effects in Syrian hamster embryo (SHE) cells. Cell growth was reduced by treatment with the steroids at 10-30 micrograms/ml in a dose-related manner. Testosterone and testosterone propionate were less toxic than the other two steroids. Testosterone, testosterone propionate and progesterone induced morphological transformation of SHE cells with similar transformation frequencies. The most potent effects were observed with testosterone propionate, which induced cell transformation at 1-30 micrograms/ml in a dose-related manner. Testosterone and progesterone transformed cells only at the highest dose (30 micrograms/ml). 17 beta-Trenbolone did not induce a statistically significant level of cell transformations at any dose tested (up to 30 micrograms/ml). The transformation frequencies induced by testosterone, testosterone propionate and progesterone were less than one-half that induced by benzo[a]pyrene at 1 microgram/ml. None of these steroids induced significant increases in frequencies of chromosome aberrations or aneuploidy. Gene mutations were not observed for testosterone at the HPRT or Na+/K+ ATPase locus. Because these steroids are also associated with carcinogenic activity in vivo, these in vitro findings provide a model and new insights into the study of the mechanisms of androgen- and progestin-induced cell transformation.
Animals↗
Acrosome reaction induced in a limited population of human spermatozoa by progesterone (Ca(2+)-dependent) and ATP (Ca(2+)-independent).
We examined the kinetics of the acrosome reaction induced in human spermatozoa by progesterone (Ca(2+)-dependent) and adenosine 5'-triphosphate (ATP; Ca(2+)-independent). ATP and progesterone did not induce the acrosome reaction unless spermatozoa were incubated in a capacitation medium. ATP exhibited a constant induction of the acrosome reaction regardless of the incubation period, while progesterone began to induce the acrosome reaction after > or = 6 h of incubation. At 24 h of incubation, the percentages of spermatozoa in which the acrosome reaction had been induced by both progesterone and ATP were almost equal. To determine whether a limited population of human spermatozoa was reactive to both progesterone and ATP, we employed an MH61 bead binding method. When the acrosome-reacted spermatozoa were removed with MH61 beads, their percentage in the sperm suspension was decreased to < 3%. At 24 h of incubation, progesterone and ATP induced the acrosome reaction in 12.0 and 10.0% of spermatozoa, respectively. After MH61 bead binding was performed, the remaining spermatozoa did not react to the other activator (progesterone-->ATP, ATP-->progesterone). These findings indicate that only a limited population of human spermatozoa has the potential to undergo the acrosome reaction when stimulated by both progesterone and ATP.
Acrosome↗
Design of a centrifugal blood pump with magnetic suspension.
A new concept blood pump, whose impeller is suspended by permanent magnets and a mechanical pivot without seals or ball bearings, is presented in this paper. The primary aim of the blood pump is an application to implantable artificial hearts. The prototype model is of a centrifugal type with a four-vaned semiopen impeller 50 mm in diameter. Since this mechanism has no seals or ball bearings, flow stagnation or heat generation that might cause blood cell denaturation is expected to be small. The results of performance testing for the prototype model 2 were satisfactory regarding pump head and efficiency. The radial-suspension magnets and the magnetic coupling were stable. As a result, the present mechanism has been verified to be a candidate applicable to implantable artificial hearts.
Biomechanical Phenomena↗
Regulation of classical HLA class I genes in human choriocarcinoma cells by nuclear proteins binding to MHC class I regulatory elements.
PROBLEM: The regulation of classical HLA class I genes in choriocarcinoma have been reported. METHODS: We determined whether four choriocarcinoma cell lines expressed classical HLA class I or HLA-G by a reverse transcription-polymerase chain reaction (RT-PCR) and studied the regulatory mechanism of classical class I using a gel mobility shift assay. RESULTS: NUC1 and SCH expressed classical class I but not HLA-G. GCH1 and Jar did neither. Nuclear protein binding to the class I regulatory element (CRE) was detected in NUC1 and SCH. Interferon-gamma augmented both classical class I expression and the DNA-protein complex in NUC1. The DNA-protein complex was not observed in GCH1, and Jar showed a CRE-binding protein with different electrophoretic mobility and binding affinity from that of SCH and NUC1. CONCLUSION: The CRE is one of the regulatory elements of classical HLA class I genes in choriocarcinoma cells.
Base Sequence↗
Short-term oral treatment of canine benign prostatic hypertrophy with chlormadinone acetate.
Ten beagle dogs (4-8 years of age) with benign prostatic hypertrophy were treated daily for 7 or 14 days by a daily oral administration of chlormadinone acetate (CMA), an anti-androgenic preparation, at a dose of 0.5 or 2.0 mg/kg/day. The groups of dogs treated with CMA at a dose of 2.0 mg/kg showed a greater reduction of the prostatic volume during 7 or 14 days of treatment than the group treated with 0.5 mg/kg of CMA. At 56 and 84 days after the start of CMA treatment, prostate volume was reduced to 63 and 79% of the pre-administration volume, respectively. No marked decrease in plasma LH or testosterone was found after the CMA treatment. These results indicate that the therapeutic effects of 7-day oral treatment with CMA at 2.0 mg/kg/day in dogs with BPH last for about three months or longer without side effects.
Administration, Oral↗
Effect of chlormadinone acetate-pellet implantation on the volume of prostate, peripheral blood levels of sex hormones and semen quality in the dog.
Chlormadinone acetate (GS implant, CMA) pellet, a synthetic luteal hormone preparation, was subcutaneously implanted at 5, 10 and 20 mg/kg in four normal male dogs ranging in age from 3 to 10 years to determine the changes in the prostatic volume, peripheral plasma levels of sex hormones and semen quality. The plasma levels of CMA, LH, testosterone (T) and 5 alpha-dihydrotestosterone (DHT) were measured by radioimmunoassay. The prostatic volume was measured by computed tomography. The semen was collected by digital manipulation. The pellet was removed 26 weeks after implantation. The effects of CMA pellet implantation were examined during implantation and until 22 weeks after removal. The prostatic volume was reduced to 61 +/- 3 (mean +/- S.E., n = 4), 52 +/- 5 (n = 4) and 53 +/- 9 (n = 4)% of the preimplantation volumes in the 5, 10 and 20 mg/kg groups, respectively. The plasma CMA levels in the 10 mg/kg and 20 mg/kg groups peaked at 2 weeks, but were gradually decreased. At 22 weeks after removal of the pellet, the prostatic volume returned to 74-85% of the preimplantation volumes. The plasma LH levels tended to increase after implantation in all groups. The plasma T and DHT levels were slightly decreased in all groups. In the 10 and 20 mg/kg groups, the number of sperm and motility sperm was reduced, and the rate of abnormal sperm increased.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Early embryonic development in vitro and embryo transfer in the cat.
Ten female cats were given a total dose of 200 IU PMSG over 3 days to induce superovulation. One to four-cell stage embryos were collected by flushing the oviducts 48 to 54 hr after the initial 250 IU dose of hCG. Some of the normal embryos collected were examined for culture in Medium-199 supplemented with 20% FCS. After 72 hr of culture, 222/248 (89.5%) had developed to the morula stage, and by 96-168 hr, 110 (64.7%) out of 170 morulae had developed into blastocysts. Four to 12 embryos cultured in vitro per cat were transferred to one of the uterine horns of 12 recipients in which synchronous ovulation had been induced with hCG. All 4 recipients of embryos which had developed to the morula stage on culture day 3, 3 of the 5 recipients of blastocysts on culture days 4-6, and none of the 3 recipients of blastocysts on culture day 7 became pregnant. It is concluded that early feline embryos are capable of efficiently developing into transferable morulae in vitro by ordinary culture methods, but that there is partial developmental arrest from the morula to the blastocyst stage.
Animals↗
Changes in peripheral plasma luteinizing hormone and testosterone concentrations and semen quality in normal and cryptorchid dogs during sexual maturation.
Changes in peripheral plasma luteinizing hormone (LH) and testosterone (T) concentrations and semen quality were investigated in four unilaterally cryptorchid (UC), three bilaterally cryptorchid (BC), and five normal beagles, from 4 to 48 weeks of age. Blood samples were collected at 2- or 4-week intervals, and the LH and T concentrations were determined by radioimmunoassay. Semen samples were collected weekly by digital manipulation. The mean LH and T concentrations in the normal dogs increased after 20 and 22 weeks of age and reached approximately 4 ng/ml and 3 ng/ml respectively at 36 weeks of age. Semen volume and total spermatozoa count increased apparently at 34 and 35 weeks of age respectively. Spermatozoa motility and percentage of abnormal spermatozoa varied less after 38 weeks of age. Plasma LH and T concentrations in the UC and BC dogs had a tendency to remain lower than values in the normal dogs after 26 weeks of age. The semen volume and spermatozoa count in the UC dogs did not increase markedly. The spermatozoa count was less than half that in normal dogs, and the percentage of abnormal spermatozoa was higher throughout the experimental period. All BC dogs had azoospermia. Thus it was evident that development of spermatogenic function during sexual maturation in the UC and BC dogs was insufficient compared with that in normal dogs.
Animals↗
Expression of intercellular adhesion molecule-1 on cultured glomerular endothelial cells by pro-inflammatory cytokines and lipopolysaccharide.
Infiltration of leukocytes and mononuclear cells into the glomeruli is an early pathological finding in human and experimental glomerulonephritis. However, the cellular and molecular basis for cell infiltration into the glomeruli is not yet completely understood. In addition, there is little information on the expression of intercellular adhesion molecule-1 (ICAM-1) on glomerular cells. In the present study, we investigated the expression of ICAM-1 on cultured bovine glomerular endothelial cells (GEN) and its regulation by the pro-inflammatory cytokines, interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and lipopolysaccharide (LPS). Immunocytochemical staining showed that ICAM-1 molecules were constitutively expressed on the surface of GEN. In flow cytometric and ELISA analyses, ICAM-1 molecule expression on GEN was significantly upregulated by IL-1 beta, MCP-1 and LPS in a dose-dependent manner, but not by IL-6. LPS was the most potent inducer of ICAM-1 molecule expression on GEN. The effects of IL-1 beta, MCP-1 and LPS were observed as early as 4 h and reached a maximal level by 18 h. These results suggest that ICAM-1 on GEN can participate in the infiltration of mononuclear cells into glomeruli in human and experimental glomerulonephritis.
Animals↗