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PubMed2003

Synthesis, toxicity and biodistribution of two 5,15-di[3,5-(nido-carboranylmethyl)phenyl]porphyrins in EMT-6 tumor bearing mice.

The total synthesis of a 5,15-di[3,5-(o-carboranylmethyl)phenyl]porphyrin 5, its zinc(II) complex 6, and the corresponding nido-carboranylporphyrins 7 and 8 are reported. The molecular structures of porphyrin 6 and of potassium nido-carborane were obtained and are described. The biodistribution of nido-carboranylporphyrins 7 and 8 in BALB/c mice bearing EMT-6 mammary tumors are presented and compared. Both compounds are effective tumor localizers and delivered therapeutic concentrations of boron to tumors (mean+/-standard deviation): 32.5+/-7.1 and 54.3+/-14 microg/g for 7 and 8, respectively, 2 days after the last of 3 injections of a total boron dose of 23 mg/kg body weight. The zinc(II) complex 8 was found to deliver 1.2-1.7 times higher amounts of boron to tumors than 7, with lower tumor-to-blood boron concentration ratios (9.8/1 and 4.7/1 for 7 and 8, respectively, 2 days after injections). The tumor-to-brain boron concentration ratios were >100/1 for both porphyrins 2 days after administration. Both nido-carboranylporphyrins 7 and 8 were well-tolerated at the concentrations used (75 and 78 mg/kg body weight, respectively) and no morbidity or mortality were observed in these studies.

Animals↗
PubMedDate not supplied

Mistaken identity: the effect of badges on EMT recognition.

INTRODUCTION: Many emergency medical services (EMS) providers wear badges with their uniforms. This study was undertaken to determine whether emergency medical technicians (EMTs) who wear badges with their uniforms are more likely to be mistaken for law enforcement personnel than are those who do not wear badges. HYPOTHESIS: Emergency medical services providers who wear badges are more likely to be mistaken for law enforcement personnel than are those who do not wear badges. METHODS: High school students, college students, civic organizations, and church groups were shown slides of different uniforms and badges/insignia and asked to identify the person portrayed. Responses were categorized as "EMS," "law enforcement," or "other." Frequency of responses for each uniform and insignia were compared with chi-square analysis. RESULTS: Fifty-nine percent of the uniforms with badges were identified as law enforcement personnel. Only 5.5% of the uniforms with badges were identified as "EMS," compared with 74% of the uniforms with a Star of Life (p < 0.001). CONCLUSION: Individuals wearing uniforms with badges are more likely to be identified as law enforcement personnel than are EMS personnel. Emergency medical services providers who do not wish to be mistaken for law enforcement personnel should wear the Star of Life, not a badge, with their uniform.

Adolescent↗
PubMed1996

Hexadecafluorinated zinc phthalocyanine: photodynamic properties against the EMT-6 tumour in mice and pharmacokinetics using 65Zn as a radiotracer.

Hexadecafluorinated zinc phthalocyanine (ZnPcF16), an analogue of zinc phthalocyanine (ZnPc) in which all hydrogen atoms have been substituted by fluorine, was prepared as a single isomeric product via the condensation of tetrafluorophthalonitrile with zinc acetate. Fluorination renders the ZnPc soluble in most common solvents. The photodynamic properties and pharmacokinetics of the ZnPcF16 were evaluated in EMT-6 tumour-bearing Balb/c mice using 65Zn-radiolabelled analogues. Both dyes, administered i.v. at 1 mumol kg-1 as Cremophor emulsions, revealed good tumour uptake [approximately 8-9 per cent of the injected dose per g tissue (%IDg-1)] at 24 h post injection (p.i.), with the fluorinated dye reaching higher concentrations (approximately 11%IDg-1) at 48 h p.i. and subsequently higher tumour-blood ratios due to rapid blood clearance. ZnPcF16 at a dose of 5 mumol kg-1 (4.3 mg kg-1) induced complete tumour regression after phototherapy (24 h p.i., 650-700 nm band, 360 J cm-2, 200 mW cm-1). At a dose of 2 mumol kg-1 and phototherapy at 24 h p.i., the tumour volume doubling time increased to 11 days vs 6 days for the control tumours. A similar tumour growth delay was observed when phototherapy was conducted at 48 h or 72 h after dye injection implying that tumour response correlates with tumour dye concentrations rather than serum concentrations. As a result of its low solubility, the administered dose of ZnPc was limited to 1 mumol kg-1 and at this drug level significant tumour response was only observed when the dye was solubilised as the pyridinium salt. Isolation of the neoplastic cells after in vivo dye administration and in vitro exposure to red light followed by a colony formation assay showed that the ZnPcF16 exhibited a 1-2 order of magnitude higher potential for direct cell killing as compared with Photofrin and about a five times lower efficiency than ZnPc. However, all three photosensitisers induced complete occlusion of tumour vasculature immediately after PDT, suggesting that tumour regression mainly resulted from vascular stasis. The ZnPcF16 offers several advantages over ZnPc for clinical applications, including improved solubility in most solvents, resulting in facilitated drug formation, favourable pharmacokinetics as well as the potential use in fluorine magnetic resonance (F-MR) imaging.

Animals↗
PubMed2003

NF-kappaB inhibition impairs the radioresponse of hypoxic EMT-6 tumour cells through downregulation of inducible nitric oxide synthase.

Hypoxic EMT-6 tumour cells displayed a high level of inducible nitric oxide synthase (iNOS) and an increased radiosensitivity after a 16 h exposure to lipopolysaccharide, a known activator of nuclear factor-kappaB (NF-kappaB). Both iNOS activation and radioresponse were impaired by the NF-kappaB inhibitors phenylarsine oxide and lactacystin. Contrasting to other studies, our data show that inhibition of NF-kappaB may impair the radioresponse of tumour cells through downregulation of iNOS.

Acetylcysteine↗
PubMed2002

Activation of the extraneuronal monoamine transporter (EMT) from rat expressed in 293 cells.

1. The extraneuronal monoamine transporter from rat (EMTr) was heterologously expressed by stable transfection in human embryonic kidney 293 cells and characterized in radiotracer experiments. 2. EMTr-mediated uptake of 1-methyl-4-phenylpyridinium (MPP(+)) was saturable, with a K(m) of 151 micro mol l(-1) and V(max) of 7.5 nmol min(-1) mg protein(-1). 3. Compared to the human orthologue EMTh (gene symbol SLC22A3), EMTr was about two orders of magnitude more resistant to most inhibitors, including disprocynium24 and corticosterone. 4. Strikingly, inhibitors and substrates at low concentration stimulated EMTr-mediated transport above control level with MPP(+) and noradrenaline as substrate, but not with cimetidine. Results were confirmed with EMT from mouse. 5. With different IC(50)-values for different substrates, the standard method to calculate K(i)-values is not applicable. 6. Our experiments suggest that activation is not caused by changes in membrane potential or trans-stimulation. Since the extent of activation depends markedly on the chemical structure of the monitored substrate, involvement of a receptor-mediated signalling pathway or recruitment of transporter reserve are implausible. 7. To explain activation, we present a kinetic model which assumes two binding sites for substrate or inhibitor per transporter entity, possibly resulting from the assembly of homodimers. 8. Activation explains previous reports about inhibitor-insensitive catecholamine transport in rat brain. 9. We speculate that activation may serve to keep the transporter working for specific substrates in the face of inhibitors.

1-Methyl-4-phenylpyridinium↗
PubMed2006

A transient, EMT-linked loss of basement membranes indicates metastasis and poor survival in colorectal cancer.

BACKGROUND & AIMS: Loss of the basement membrane (BM) is considered an important step toward tumor malignancy. However, the BM is still expressed in most typical colorectal adenocarcinomas; nevertheless, these tumors can invade and develop metastases. The aim of this study was to investigate the role, mechanisms, and clinical relevance of BM turnover in malignant colorectal cancer (CRC) progression. METHODS: Expression of BM components and their transcriptional regulation and clinical relevance were investigated in human CRCs and cell lines. RESULTS: Our data show new aspects in BM turnover in CRCs with impact on malignant tumor progression: (1) The BM is still expressed in the main tumor mass of most colorectal adenocarcinomas, but selectively lost at invasive regions of the tumor in many cases. (2) Selective loss of the BM at the invasive front has high clinical and tumor biologic relevance for distant metastasis and survival. (3) The BM is reexpressed in metastases, indicating that its loss is transient and regulated by environmental factors. (4) This transient loss is not only due to proteolytic breakdown but to a down-regulated synthesis and linked to an epithelial-mesenchymal transition (EMT) in tumor cells, and, thereby, zinc-finger-enhancer protein 1 (ZEB1) is the crucial transcriptional repressor of BM components in CRCs. CONCLUSIONS: A transient BM loss at the invasive front is correlated with increased distant metastasis and poor patient survival, indicating its tumor biologic relevance and usefulness as a prognostic marker. Targeting ZEB1 might be a promising therapeutic option to prevent metastasis.

Adenocarcinoma↗
PubMed1978

[Clinical experience with the cage electrode EMT 588 K. Threshold--current consumption--postoperative complications (author's transl)].

The Lagergren cage electrode Elema EMT 588 K was implanted in 26 male and 21 female patients for permanent cardiac stimulation. 29 of the 47 cage electrodes were fitted with a platinum and 18 with an Elgiloy head. Acute threshold in the platinum group was 0,52 +/- 0,15 volts (x +/- s), the equivalent electrode resistance being 565 +/- 135 ohms. The threshold mean value for the Elgiloy cage electrodes was shown to be 0,36 +/- 0,11 volts, while the resistance values measured respectively 410 +/- 44 and 418 +/- 23 ohms depending on the method of measurement. In the postoperative period (up to 16 months) the following complications were observed: 3 dislocations (6,38%) and one case of rise in threshold (2,12%). The total correction rate (8,5%) corresponds almost exactly to that recorded by the author in a personal series of 400 electrode implantations of various designs. The cage electrode offers no advantages in comparison to other small surface electrodes, however, the relatively higher current consumption caused by low total electrode resistance must be regarded as disadvantages. Experience with the cage electrode has shown that the transitional resistance depends not only on the surface, but also essentially on the material and shape of the electrode tip.

Alloys↗
PubMed1981

Comparative effects of 60Co gamma-rays and neon and helium ions on cycle duration and division probability of EMT 6 cells. A time-lapse cinematography study.

Exponentially growing cultures of EMT 6 cells were irradiated in vitro with neon ions, helium ions or 60Co gamma-rays. Time-lapse cinematography allowed the determination, for individual cells, of cycle duration, success of the mitotic division and the age of the cell at the moment of irradiation. Irradiation induced a significant mitotic delay increasing proportionally with the delivered dose. Using mitotic delay as an endpoint, the r.b.e. for neon ions with respect to 60Co gamma-rays was 3.3 +/- 0.2 while for helium ions it was 1.2 +/- 0.1. Mitotic delay was greatest in those cells that had progressed furthest in their cycle at the time of irradiation. No significant mitotic delay was observed in the post-irradiation generation. Division probability was significantly reduced by irradiation both in the irradiated and in the post-irradiated generation. The reduction in division probability obtained with 3 Gy of neon ions was similar to that obtained after irradiation with 6 Gy of helium ions or 60Co gamma-rays.

Cell Cycle↗
PubMed1995

Dynamic scaling in the dielectric response of excised EMT-6 tumours undergoing hyperthermia.

A constant-phase-angle response (CPA) has been identified in the dielectric spectrum of EMT-6 tissues undergoing hyperthermia. A dynamic scaling relationship between the static permittivity and conductivity using the CPA frequency exponent n has been shown to occur during the destructive phase of hyperthermia. This behaviour has been attributed to the self-similar structure of the internal membrane compartments of the cells and described by means of a hierarchical circuit model. In this way the CPA exponent has been related to the convolution of internal membrane surfaces lying in between the mitochondria and the outer cell wall. The dynamic scaling is assigned to the progressive destruction of cell membranes in sequence from the outside inwards.

Animals↗
PubMed2005

SIP1/ZEB2 induces EMT by repressing genes of different epithelial cell-cell junctions.

SIP1/ZEB2 is a member of the deltaEF-1 family of two-handed zinc finger nuclear factors. The expression of these transcription factors is associated with epithelial mesenchymal transitions (EMT) during development. SIP1 is also expressed in some breast cancer cell lines and was detected in intestinal gastric carcinomas, where its expression is inversely correlated with that of E-cadherin. Here, we show that expression of SIP1 in human epithelial cells results in a clear morphological change from an epithelial to a mesenchymal phenotype. Induction of this epithelial dedifferentiation was accompanied by repression of several cell junctional proteins, with concomitant repression of their mRNA levels. Besides E-cadherin, other genes coding for crucial proteins of tight junctions, desmosomes and gap junctions were found to be transcriptionally regulated by the transcriptional repressor SIP1. Moreover, study of the promoter regions of selected genes by luciferase reporter assays and chromatin immunoprecipitation shows that repression is directly mediated by SIP1. These data indicate that, during epithelial dedifferentiation, SIP1 represses in a coordinated manner the transcription of genes coding for junctional proteins contributing to the dedifferentiated state; this repression occurs by a general mechanism mediated by Smad Interacting Protein 1 (SIP1)-binding sites.

Binding Sites↗
PubMed1998

Antitumor activity of tricyclic pyrone analogs, a new synthetic class of microtubule de-stabilizing agents, in the murine EMT-6 mammary tumor cell line in vitro.

Novel tricyclic pyrone (TP) analogs synthesized in Hua's laboratory (code names H10, H14 and H16) were tested against a spectrum of known antimitotic drugs for their ability to disrupt microtubule (MT) dynamics, alter the mitotic index, and prevent murine EMT-6 mammary sarcoma cells from synthesizing DNA and proliferating in vitro. At 2-10 microM, H10 inhibits DNA synthesis, tubulin polymerization and tumor cell growth to a greater degree than H14, whereas H16 has no effect. A linear skeleton with a pyridyl ring at C-3 of the A-ring, a pyran B-ring and no alkylation at C-7 of the C-ring is required for the antitumor activity of these TPs. Since H10 mimics the effect of vincristine (VCR), but not that of paclitaxel, on tubulin polymerization, TPs may represent a novel synthetic class of MT de-stabilizing anticancer drugs. H10 is less potent than VCR against tubulin polymerization (IC50: 1.5 microM versus 0.15 microM) and tumor cell proliferation (IC50: 1.5 microM versus 5 nM) but inhibits DNA synthesis (IC50: 10 microM) more effectively than all other MT-disrupting agents tested, except tubulozole-C. Although TPs disrupt DNA synthesis and might affect several phases of the cell cycle, the ability of H10 to increase the percentage of mitotic cells indicates that these novel compounds may be cell cycle-specific anticancer drugs useful for arresting mammalian cells in M-phase.

Animals↗
PubMed1995

PEG-coated poly(lactic acid) nanoparticles for the delivery of hexadecafluoro zinc phthalocyanine to EMT-6 mouse mammary tumours.

Hexadecafluoro zinc phthalocyanine (ZnPcF16), a second generation sensitizer for the photodynamic therapy of cancer, was incorporated in three vehicles: poly(D,L-lactic acid) (PLA) nanoparticles, polyethylene glycol (PEG)-coated nanoparticles and a Cremophor EL (CRM) oil-water emulsion. Nanoparticles were prepared by the salting-out procedure. Biodistribution of the dye was assessed by fluorescence in EMT-6 mammary tumour bearing mice after intravenous injection of 1 mumol kg-1 ZnPcF16. Plain nanoparticles were rapidly retained by the reticuloendothelial system (RES) as reflected by the low area under the blood concentration-time curve (AUC0-168, 57 micrograms h g-1). Little tumour uptake of the dye was observed with this formulation. In contrast, PEG-coated nanoparticles displayed a reduced RES uptake, leading to significantly higher blood levels over an extended period (t1/2 30 h; AUC 0-168 227 micrograms h g-1) and enhanced tumour uptake. At 48 h post injection, tumour to skin and tumour to muscle concentration ratios reached 3.5 and 10.8, respectively. Blood levels of ZnPcF16 after administration as a CRM emulsion decreased faster than with PEG-coated nanoparticles (t1/2 12 h), but since no early liver uptake was observed, the AUC0-168 and the tumour uptake were only slightly lower. However, with the CRM formulation, a late liver uptake was observed, reaching 51% of the injected dose after 7 days.

Animals↗
PubMed1977

Cure of EMT-6 tumors by X rays or neutrons: effect of mixed-fractionation schemes.

EMT-6 mouse tumors were treated with (a) 1 or 5 fractions of either x rays or neutrons or (b) a mixture of both in which 2 fractions of neutrons (n) plus 3 fraction of x rays (x) were given in 5 days in the sequence n-n-x-x-x or n-x-x-x-n. Using local tumor control as an end point, neutron RBEs of 1.7 for single fractions and 2.6 for 5 fractions were obtained. The two mixed schemes yielded RBEs of 1.5 and 1.4, respectively. Therapeutic gain factors, calculated as the ratio of tumor to skin RBE with neutrons or mixed radiations, were highest for the mixed fractionation schemes. These results are due to an apparent enhancement of the neutron effect in the tumor but not in the skin with these regimens. Other normal tissues must be irradiated with mixed schemes to determine whether this phenomenon is limited to the skin.

Animals↗
PubMed1979

Pharmacologic enhancement of gallium-67 tumor-to-blood ratios for EMT-6 sarcoma (BALB/c mice).

At various intervals after intravenous injection of carrier-free 67Ga-citrate, iron dextrane or deferoxamine mesylate was injected into EMT-6 tumor-bearing BALB/c mice. After treatment, rapid clearance of 67Ga from soft tissues was observed. Tumor uptake was not greatly affected, and so increased tumor-to-blood ratios were observed. The authors conclude that these drugs can enhance target-to-nontarget uptake ratios for tumors.

Animals↗
PubMed1983

The labelling of EMT-6 tumours in BALB/C mice with 14C-misonidazole.

14C-misonidazole was injected IP into BALB/C mice bearing EMT-6 tumours. Tumour and normal tissue levels of radioactivity were determined by liquid scintillation procedures for times up to 72 h after drug administration. At times longer than 8 h, levels of 14C in tumour were 2-6 times higher than 14C levels measured in other normal tissues, with the exception of liver. The levels of 14C from misonidazole retained in liver tissue were comparable to those retained in the tumours. The clearance of 14C-misonidazole from the tumours and all normal tissues could be characterised by two distinct phases: a rapid phase (0.7 h half-life) followed by a much slower phase (approximately 50 h half-life). The distribution of retained 14C from labelled misonidazole within tumour-bearing mice was also measured by whole animal autoradiographic techniques. This procedure confirmed the biodistribution of 14C-misonidazole determined by liquid scintillation procedures. To enhance binding to hypoxic cells in vivo, 14C-misonidazole was administered in multiple doses over a three-hour period, simulating a prolonged exposure to the drug. The 14C from labelled misonidazole retained in tumour tissue was 4-15 times greater than that retained in normal tissues, liver tissue being again an exception. Myocardial ischaemia was induced by isoproterenol treatment and a two-fold increase of 14C from labelled misonidazole was found in the heart tissue of mice treated by the drug compared to controls. The increased binding of 14C-misonidazole to tumour cells after prolonged exposure to the drug and the increased binding of 14C-misonidazole to ischaemic heart tissue suggests that hypoxia is a factor in sensitiser adduct formation in vivo.

Animals↗
PubMed2004

Use of the Gamow Bag by EMT-basic park rangers for treatment of high-altitude pulmonary edema and high-altitude cerebral edema.

As part of an emergency medical system protocol, national park service rangers certified at the level of an emergency medical technician-basic (EMT-B) are taught to recognize and treat high-altitude pulmonary edema and high-altitude cerebral edema. In Sequoia and Kings Canyon National Parks, this is done with the assistance of physician on-line medical control as a backup. High-altitude pulmonary edema and high-altitude cerebral edema are both potentially fatal altitude illnesses that can be particularly problematic in the backcountry, where evacuation may be delayed. We report a case of high-altitude pulmonary edema and high-altitude cerebral edema occurring at moderate altitude that was successfully treated by park rangers with the Gamow Bag.

Adult↗
PubMed2003

Murine EMT-6 carcinoma: high therapeutic efficacy of microbeam radiation therapy.

Microbeam radiation therapy is an experimental modality using parallel arrays of thin (<100 micro m) slices of synchrotron-generated X rays (microplanar beams, microbeams). We used EMT-6 murine mammary carcinoma subcutaneously inoculated in the hind legs of mice to compare the therapeutic efficacies of single-fraction, unidirectional (1) "co-planar" microbeams (an array of vertically oriented microplanar beams), (2) "cross-planar" microbeams (two arrays of parallel microbeams propagated in the same direction, one with vertically and the other with horizontally oriented microplanar beams), and (3) seamless (broad) beams from the same synchrotron source. The microbeams were 90 micro m wide and were spaced 300 micro m on center; the median energy in all beams was 100 or 118 keV. Tumor ablation rates were 4/8, 4/8 and 6/7 for a 410-, 520- and 650-Gy in-slice cross-planar microbeam dose, respectively, and 1/8, 3/8, 3/7 and 6/8 for a 23-, 30-, 38- and 45-Gy broad-beam dose, respectively. When the data were pooled from the three highest doses (same average tumor ablations of 50-60%), the incidences of normal-tissue acute toxicity (moist desquamation and epilation) and delayed toxicity (failure of hair regrowth) were significantly lower for cross-planar microbeams than broad beams (P < 0.025). Furthermore, for the highest doses in these two groups, which also had the same tumor ablation rate (>75%), not only were the above toxicities lower for the cross-planar microbeams than for the broad beams (P < 0.02), but severe leg dysfunction was also lower (P < 0.003). These findings suggest that single-fraction microbeams can ablate tumors at high rates with relatively little normal-tissue toxicity.

Animals↗
PubMedDate not supplied

Non-invasive, in-vivo electrical impedance of EMT-6 tumours during hyperthermia: correlation with morphology and tumour-growth-delay.

The electrical impedance at frequencies from 100 Hz to 40 MHz of EMT-6 tumours was measured non-invasively, in vivo, during hyperthermia using an apparatus constructed for this purpose. Histology and morphometry were performed on tumours harvested periodically during the heating. A ratio of conductivities at two frequencies (sigma (10MHz)/sigma (10kHz)), which minimizes the tissues temperature-coefficient effects, was used to correlate impedance changes with the histopathological changes. The bulk of the cell population followed a necrotic cell death sequence during heating. Initial increase of the sigma-ratio correlated with cell swelling, and a reversal of the rate of this increase correlated with the appearance of small membrane breaks and evidence of mitochondrial damage. A continued, slowing sigma-ratio increase to a maximum correlated with continued cell swelling accompanied by increasing membrane disruption. The subsequent decrease in sigma-ratio correlated with continued general cell lysing. Between the appearance of the first membrane breaks (sigma-ratio peak) and the evidence of general lysing (sigma-ratio peak), the tumour-growth-delay increased non-linearly. Because the sigma-ratio consistently discerned these events, these measurements were able to predict the fate of this cell population when subjected to hyperthermia. Knowledge of temperature or time of heating was not required.

Animals↗