Caffeine suppresses metastasis in a transgenic mouse model: a prototype molecule for prophylaxis of metastasis

A significant fraction of cancer patients have occult disseminated tumors at the time of primary diagnosis, which usually progress to become clinically relevant lesions. Since the majority of cancer mortality is associated with metastatic disease, the ability to inhibit the growth of the secondary tumors would significantly reduce cancer-related morbidity and mortality. We have investigated whether caffeine, which has been shown to suppress tumor cell invasiveness and experimental metastasis, can suppress metastasis in a spontaneous transgene-induced mammary tumor model. Chronic exposure to caffeine prior to the appearance of palpable mammary tumors significantly reduced both tumor burden and metastatic colonization. However, when caffeine exposure began after the appearance of frank tumors, caffeine suppressed metastasis without changing primary tumor burden. The means by which caffeine suppressed metastatic activity may be associated with inhibition of malignant transformation of mammary epithelial cells, inhibition of conversion of dormant tumor cells to micrometastases, micrometastases to macrometastases, or inhibition of tumor cell adhesion and motility. Gene and protein expression patterns resulting from caffeine treatment showed that metastasis suppression may be associated with up-regulation the mRNA expression of multiple extracellular matrix genes, including Fbln1, Bgn, Sparc, Fbn1, Loxl1, Colla1, Col3a1, Col5a1, ColS5a2, ColSa3, Col6a1, Col6a2, and Col6a3. These data suggested that caffeine or other methyl xanthine derivatives may improve the clinical outcome in patients prior to and following the diagnosis of metastatic disease, and could potentially reduce the morbidity and mortality associated with disseminated tumors.

The Collaborative Cross, a community resource for the genetic analysis of complex traits

The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease.

Modeling metastasis in vivo

Metastasis, the spread of a tumor from its primary site to other parts of the body, continues to be the most significant problem in the field of cancer. Patients who present with metastatic disease or those who develop metastases after successful management of the primary tumor carry a universally grave prognosis. To improve treatment outcomes for these patients a broader understanding of the biology of metastases is necessary. The biological complexity that characterizes metastasis requires complex experimental systems for its study. To a large extent the modeling of this biological complexity is only possible using animal models. The following review will summarize the strengths and weaknesses of available in vivo models of metastasis including transplantable syngeneic mouse and human-mouse xenografts, genetically engineered mice and naturally occurring cancers of companion animals (pet dogs and cats). No single metastasis model is sufficient to answer all questions. As such, the selection of the optimal model(s) for each biological or translational question is necessary.

Antimony distribution and environmental mobility at an historic antimony smelter site, New Zealand

A historic antimony smelter site at Endeavour Inlet, New Zealand has smelter residues with up to 17 wt.% antimony. Residues include coarse tailings (cm scale particles, poorly sorted), sand tailings (well sorted) and smelter slag (blocks up to 30 cm across). All of this material has oxidised to some degree over the ca. 100 years since the site was abandoned. Oxidation has resulted in acidification of the residues down to pH 2-5. Smelter slag contains pyrrhotite (FeS) and metallic antimony, and oxidation is restricted to surfaces only. The coarse tailings are the most oxidised, and few sulfide grains persist. Unoxidised sand tailings contain 10-20 vol.% stibnite (Sb2S3) containing up to 5% As, with subordinate arsenopyrite (FeAsS), and minor pyrite (FeS2). The sand tailings are variably oxidised on a scale of 2-10 cm, but original depositional layering is preserved during oxidation and formation of senarmontite (Sb2O3). Oxidation of sand tailings has resulted in localised mobility of both Sb and As on the cm scale, resulting in redistribution of these metalloids with iron oxyhydroxide around sand grain boundaries. Experiments demonstrate that Sb mobility decreases with time on a scale of days. Attenuation of both As and Sb occurs due to adsorption on to iron oxyhydroxides which are formed during oxidation of the smelter residues. There is no detectable loss of Sb or As from the smelter site into the adjacent river, <50 m away, which has elevated Sb (ca. 20 microg/l) and As (ca. 7 microg/l) from mineralised rocks upstream. Despite the high concentrations of Sb and As in the smelter residues, these metalloids are not being released into the environment.

Genetic, genomic, and bioinformatic tools for studying breast cancer progression

Cancer susceptibility is a complex interaction of an individual's genetic composition and environmental exposures. Huge strides have been made in understanding cancer over the past 100 years, from the recognition of cancer as a genetic disease, to the identification of specific carcinogens, isolation of oncogenes and the recognition of tumor suppressors. Analysis of high-risk familial cancers has led to the discovery of new tumor suppressor genes and important cancer pathways. These families however represent only a small fraction of cancer in the general population. Most cancer instead probably results of an intricate interaction of polymorphic susceptibility genes with the sea of environmental exposures that humans experience. Although the central cadre of cancer genes is known, little is understood about the peripheral genes that likely comprise the polymorphic susceptibility loci. The challenge for cancer genetics is therefore to move forward from the Mendelian genetics of the rare familial cancer syndromes into the field of quantitative trait loci, susceptibility factors, and modifier genes. By identifying the genes that modulate an individual's susceptibility to cancer after an environmental exposure, researchers will be able to gain important insights into human biology, cancer prevention and treatment. The most efficient strategies to identify and characterize modifier loci will likely be those that are transdisciplinary, encompassing a variety of different "-omic" technologies. The application of a "trans-omic" techniques in our laboratory to the study of breast cancer dissemination is presented here as an illustration of the strategy.

The nature and identification of quantitative trait loci: a community's view

This white paper by eighty members of the Complex Trait Consortium presents a community's view on the approaches and statistical analyses that are needed for the identification of genetic loci that determine quantitative traits. Quantitative trait loci (QTLs) can be identified in several ways, but is there a definitive test of whether a candidate locus actually corresponds to a specific QTL?

Susceptibility to aflatoxin B1-related primary hepatocellular carcinoma in mice and humans

The genetic basis of disease susceptibility can be studied by several means, including research on animal models and epidemiological investigations in humans. The two methods are infrequently used simultaneously, but their joint use may overcome the disadvantages of either method alone. We used both approaches in an attempt to understand the genetic basis of aflatoxin B(1) (AFB(1))-related susceptibility to hepatocellular carcinoma (HCC). Ingestion of AFB(1) is a major risk factor for HCC in many areas of the world where HCC is common. Whether humans vary in their ability to detoxify the active intermediate metabolite of AFB(1), AFB(1)-exo-8,9-epoxide, is not certain but may explain why all exposed individuals do not develop HCC. To determine whether human variability in detoxification may exist, in a study of 231 HCC cases and 256 controls, we genotyped eleven loci in two families of AFB(1) detoxification genes; the glutathione S-transferases (GSTs) and the epoxide hydrolases (EPHX). After adjustment for multiple comparisons, only one polymorphism in the epoxide hydrolase family 2 locus remained significantly associated with HCC (odds ratio = 2.06, 95% confidence interval = 1.13-3.12). To determine whether additional susceptibility loci exist, we developed a mouse model system to examine AFB(1)-induced HCC. Susceptibility of 7-day-old mice from two common inbred strains (C57BL/6J, DBA/2J) was assessed. DBA/2J animals were 3-fold more sensitive to AFB(1)-induced HCC and significantly more sensitive to AFB(1) acute toxicity than were C57BL/6J animals. Analysis of the xenobiotic metabolizing genes in the two strains revealed single nucleotide polymorphisms in three genes, Gsta4, Gstt1, and Ephx1. Although the GSTT1 and EPHX1 loci did not appear to be related to HCC in the total population of the human study, a polymorphism in GSTA4 was significantly related to risk in the male subset. The mouse model also demonstrated that absent or compromised p53 was not necessary for the development of carcinogenesis. These results indicate that the comparison of results from human studies and the AFB(1)-susceptible mouse model may provide new insights into hepatocarcinogenesis.

The Septin 9 (MSF) gene is amplified and overexpressed in mouse mammary gland adenocarcinomas and human breast cancer cell lines

The expression of polyomavirus middle T antigen under the control of the mouse mammary tumor virus promoter in transgenic mice results in the induction of aggressive mammary gland adenocarcinomas at an early age. We screened 26 tumors for chromosomal aneuploidies using SKY and CGH. In 70% of the tumor samples we could detect high-level copy number gains, which mapped to chromosome band 11E2, a region orthologous to human 17q25.3. We then identified a bacterial artificial chromosome clone that labeled double-minute chromosomes found in the tumor metaphases. This bacterial artificial chromosome clone showed sequence homology to a member of the septin gene family. Real-time PCR analysis revealed a consistently increased expression of septin 9 (Sept9), not only in polyomavirus middle T antigen-induced, but in a wide variety of mouse models of breast cancer. Six of 9 human tumor cell lines also revealed elevated expression levels of Sept9. The family of septin genes is involved in a plethora of cellular processes, including cytokinesis in yeast and vesicle transport, and possesses GTPase activity. We identified down-regulation of Thsp1- and Bax-regulated apoptotic response in those tumors with Sept9 overexpression, an effect that could be reversed by inhibiting Sept9 expression using transfection with small interference RNA. Our results now suggest that signaling via members of the septin family plays a novel and common role in breast tumorigenesis.

The development of a highly informative mouse Simple Sequence Length Polymorphism (SSLP) marker set and construction of a mouse family tree using parsimony analysis

To identify highly informative markers for a large number of commonly employed murine crosses, we selected a subset of the extant mouse simple sequence length polymorphism (SSLP) marker set for further development. Primer pairs for 314 SSLP markers were designed and typed against 54 inbred mouse strains. We designed new PCR primer sequences for the markers selected for multiplexing using the fluorescent dyes FAM, VIC, NED, and ROX. The number of informative markers for C57BL/6J x DBA/2J is 217, with an average spacing of 6.8 centiMorgans (cM). For all other pairs of strains, the mean number of informative markers per cross is 197.0 (SD 37.8) with a mean distance between markers of 6.8 cM (SD 1.1). To confirm map positions of the 224 markers in our set that are polymorphic between Mus musculus and Mus spretus, we used The Jackson Laboratory (TJL) interspecific backcross mapping panel (TJL BSS); 168 (75%) of these markers had not been previously mapped in this cross by other investigators, adding new information to this community map resource. With this large data set, we sought to reconstruct a phylogenetic history of the laboratory mouse using Wagner parsimony analysis. Our results are largely congruent with the known history of inbred mouse strains.

Transcranial magnetic stimulation for the treatment of seizures: a controlled study

OBJECTIVE

To perform a controlled trial of transcranial magnetic stimulation (TMS).

METHODS

Twenty-four patients with localization-related epilepsy were randomized to blinded active or placebo stimulation. Weekly seizure frequency was compared for 8 weeks before and after 1 week of 1-Hz TMS for 15 minutes twice daily.

RESULTS

When the 8-week baseline and post-stimulation periods were compared, active patients had a mean seizure frequency reduction of 0.045 +/- 0.13 and sham-stimulated control subjects -0.004 +/- 0.20. Over 2 weeks, actively treated patients had a mean reduction in weekly seizure frequency of 0.16 +/- 0.18 and sham-stimulated control subjects 0.01 +/- 0.24. Neither difference was significant.

CONCLUSION

The effect of TMS on seizure frequency was mild and short lived.

Prognosis following first acute myocardial infarction in Type 2 diabetes: a comparative population study

AIMS

To estimate the incidence of death and macrovascular complications after a first myocardial infarction for patients with Type 2 diabetes.

RESEARCH DESIGN

In a retrospective, incidence cohort study in the Tayside Region of Scotland we studied all patients hospitalized with a diagnosis of first acute myocardial infarction from 1 April 1993 to 31 December 1994. The primary endpoint was time to death. Secondary endpoints were 2-year incidence of hospital admission for angina, myocardial infarction, stroke, heart failure, coronary angiography, coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA).

RESULTS

The 147 patients with Type 2 diabetes had significantly worse survival with an increase in relative hazard of 67% compared with non-diabetic patients. After adjustment for age, sex, smoking status, prior heart failure, prior angina, delay to hospitalization, site of infarction, drug therapy with aspirin, beta-blockers, streptokinase and hyperlipidaemia and treated hypertension, Type 2 diabetes was still associated with a 40% higher death rate compared with people without diabetes (P < 0.05) There was no significant difference in death rates in those aged over 70 years, but an indication of a trend in younger individuals with a four-fold increase in death rate in those with diabetes aged < 60 years, compared with a rate ratio of 2.6 in those with diabetes aged 61-70 years.

CONCLUSIONS

Among hospitalized patients with first acute myocardial infarction, Type 2 diabetes mellitus is consistently associated with increased mortality and increased hospital admission for heart failure. The estimated 4-year survival rate is only 50%. Our results indicate that younger subjects with Type 2 diabetes and acute myocardial infarction are a high-risk group deserving of special study, and support the argument for aggressive targeting of coronary risk factors among patients with Type 2 diabetes.

Initiating oncogenic event determines gene-expression patterns of human breast cancer models

Molecular expression profiling of tumors initiated by transgenic overexpression of c-myc, c-neu, c-ha-ras, polyoma middle T antigen (PyMT) or simian virus 40 T/t antigen (T-ag) targeted to the mouse mammary gland have identified both common and oncogene-specific events associated with tumor formation and progression. The tumors shared great similarities in their gene-expression profiles as compared with the normal mammary gland with an induction of cell-cycle regulators, metabolic regulators, zinc finger proteins, and protein tyrosine phosphatases, along with the suppression of some protein tyrosine kinases. Selection and hierarchical clustering of the most variant genes, however, resulted in separating the mouse models into three groups with distinct oncogene-specific patterns of gene expression. Such an identification of targets specified by particular oncogenes may facilitate development of lesion-specific therapeutics and preclinical testing. Moreover, similarities in gene expression between human breast cancers and the mouse models have been identified, thus providing an important component for the validation of transgenic mammary cancer models.

Noninvasive imaging by optical coherence tomography to monitor retinal degeneration in the mouse

PURPOSE

Optical coherence tomography (OCT) is a high-resolution imaging technique that measures the intensity of backscattered light from biological microstructures in living tissue. The objective was to evaluate OCT as a routine, noninvasive technique for quantitative measurements of retinal thickness and detachment in small animal models of retinal degenerative diseases.

METHODS

An OCT scanning unit was designed and built to visualize retinal tissue from rodents at high resolution in vivo. Several normal and retinal degeneration (rd) mouse strains with different pigmentation, as well as a transgenic mouse strain that carries a wild-type beta-PDE gene in an rd/rd background, were analyzed at different ages. Retinal detachment was induced by subretinal injection of saline. Retinal function was evaluated by full-field ERG, and then each retina was cross-sectionally scanned by OCT. OCT image analysis and measurements of retinal thickness were performed. Animals were then killed and retinal histology was documented.

RESULTS

OCT images of the mouse retina revealed structural landmarks allowing assignment of retinal structures. There was no difference in the OCT pattern between pigmented and nonpigmented mice. Changes in the retinal thickness measured by OCT correlated very well with the loss in function measured by ERG and histology in rd/rd and rd/rd/tg(+) transgenic mice at a variety of ages. In addition, retinal detachment caused by surgery was easily visualized and observed by OCT imaging.

CONCLUSIONS

OCT imaging is applicable to the mouse retina. There is excellent agreement between the retinal thickness measured by OCT, ERG amplitude, and retinal histology, thus validating OCT imaging as a sensitive and noninvasive tool for monitoring the structural progression of retinal diseases in rodent models. OCT also appears useful for visualizing retinal detachments in the mouse.

Modulation of the inflammatory response in the cardiomyocyte and macrophage

Numerous cardiac disease processes have been linked to the overproduction of nitric oxide (NO) via inducible nitric oxide synthase (iNOS) in the cardiovascular system. Chronic and acute exposure to hyperphysiologic levels of NO has been suggested as an agent in chronic transplant rejection, various cardiomyopathies, reperfusion injury, and the inflammatory state following cardiopulmonary bypass. Proinflammatory cytokines and inflammatory cell types, such as macrophage and neutrophils, have also been implicated in the pathophysiology associated with the previously mentioned syndromes. Previous work by this group has shown that lipopolysaccharide (LPS) in combination with tumor necrosis factor-alpha (TNF-alpha) can increase iNOS expression and the production of NO in macrophage. With this in mind, we hypothesized that increased iNOS expression and NO production generated by LPS and TNF-alpha in the macrophage could be mimicked in the cardiomyocyte and potentially account for some aspect of the cardiac dysfunction attributed to NO. Furthermore, this increased expression of iNOS and NO production could be returned to control using the glucocorticoid, dexamethasone, a known iNOS transcription blocker. Using fetal rat cardiomyocytes in primary culture cell line and a murine macrophage cell line, RAW 264.7, the expression of iNOS was quantified with specific FITC-conjugated antibodies using fluorescence activated cell sorter (FACS) and NO production with a Bioxytech nitric oxide spectrophotometric assay. The myocytes and macrophage were separated into three groups, Control, TNF + LPS, and (+) Dexamethasone. The control groups received no TNF or LPS or dexamethasone, TNF + LPS groups received TNF-alpha and LPS for 8 hours with no dexamethasone, and the (+) Dexamethasone groups were pretreated with dexamethasone for 8 hours and stimulated with TNF-alpha and LPS along with a second 8-hour treatment of dexamethasone. The macrophage cell groups treated with TNF-alpha and LPS showed a 335% increase over control in iNOS expression, and NO production was increased 494% from control. Macrophage treated with dexamethasone experienced an attenuation of iNOS expression of 200% toward control from stimulated levels and 202% decrease in NO production from stimulated levels toward control. Cardiomyocytes exhibited no statistically significant change in the expression of iNOS or NO production with stimulation or dexamethasone treatments. In conclusion, iNOS and NO were elevated in macrophage, which can be blunted in the presence of dexamethasone in the macrophage. Curiously, iNOS could not be stimulated in the cardiomyocyte, suggesting inflammatory cells may be largely responsible for the elevated iNOS and NO experienced in some cardiovascular diseases. The clinical relevance of this study is the introduction of specific iNOS inhibitors into the cardiopulmonary bypass circuit could serve as a potential mechanism for modulating the inflammatory response surrounding cardiopulmonary bypass. Likewise, therapeutic glucocorticoid administration could improve outcomes for patients with inflammatory cardiovascular disease states related to elevated NO production.

Simulation of ischemic reperfusion in endothelial cell culture increases apoptosis

The endothelial layer of the myocardial vasculature serves as an important protective barrier between blood and myocardium. Ischemic reperfusion (I/R) of the endothelium has been shown to initiate a series of events that leads to ischemic reperfusion injury in the heart. At the onset of ischemic reperfusion, endothelial cells initiate apoptosis, a process whereby the cells self-destruct. Ischemic reperfusion was simulated to study its effects on the induction of apoptosis in cultured human endothelial cells (ECV 304). In addition, the cells were treated with nitric oxide (NO) to test its effect on induction of apoptosis. To mimic hypoxia, four ECV 304 cultures were placed in a medium that had been bubbled with pure nitrogen gas for 24 hours. A continuous flow of nitrogen gas was applied to the culture flasks during the course of the 2-hour ischemic period. After 2 hours, the nitrogen was removed from the hypoxic cultures to simulate reperfusion. Exposure to NO was achieved through the NO-donor (+/-)-S-nitroso-N-acetylpenicillamine (SNAP) at 100 microM, Cell cultures were exposed to hypoxia only, hypoxia and SNAP, and SNAP only. One positive control was established by exposure to staurosporine. A second positive control was established by exposure to a 30-min heat treatment at 43 degrees C. Two cultures were left untreated to serve as negative controls. All cell cultures were incubated for 4 hours. Apoptosis was detected by the binding of annexin V-fluorescein isothiocyanate (annexin V-FITC). In addition, morphologic changes detected by electron microscopy were used. Apoptosis increased in all treated cultures, excluding SNAP only treated cells. It was concluded that I/R may lead to induction of apoptosis.

Cortical localization of reading in normal children: an fMRI language study

BACKGROUND

fMRI provides a noninvasive means of identifying the location and organization of neural networks that underlie cognitive functions.

OBJECTIVE

To identify, using fMRI, brain regions involved in processing written text in children.

METHODS

The authors studied nine normal right-handed native English-speaking children, aged 10.2 years (range 7.9 to 13.3 years), with two paradigms: reading Aesop's Fables and "Read Response Naming" (reading a description of an object that was then silently named). Data were acquired using blood oxygen level-dependent fMRI. Group data were analyzed with statistical parametric mapping; individual data sets were analyzed with a region-of-interest approach from individual study t maps. The number of activated pixels was determined in brain regions and an asymmetry index (AI = [L - R]/[L + R]) calculated for each region.

RESULTS

The authors found strong activation in the left middle temporal gyrus and left midfrontal gyrus and variable activation in left inferior frontal gyrus for both reading tasks in the group analysis (z > 5.5 to 9.1). All subjects had strong left-sided lateralization for both tasks in middle/superior temporal gyrus, inferior frontal gyrus, and middle frontal gyrus (AI = 0.76 to 1.0 for t = 4). Reading Fables activated twice as many pixels in temporal cortex as the Read Response Naming task; activation in dorsolateral prefrontal cortex was similar for both tasks. Small homologous right middle temporal region activation was seen with reading a fable.

CONCLUSIONS

The neural networks that process reading appear to be lateralized and localized by middle to late childhood. Reading text paradigms may prove useful for identifying frontal and temporal language-processing areas and for determining language dominance in children experiencing epilepsy or undergoing tumor surgery.

Differential effects of acute ethanol treatment on cardiac contractile function in young adult and senescent mice

It is understood that marked biochemical, molecular, and performance alterations occur in cardiovascular tissues related to aging. It is logical, therefore, that differences in the cardiovascular response to ethanol consumption, when comparing younger with older individuals, may exist. We compared the left ventricular function of 6- and 15-month-old (senescent) mice and 16-month-old (senescent) inducible nitric oxide synthase knockout mice (n=7 each) before and subsequent to acute treatment with 60% ethanol (2 g/kg, i.p.). A Millar 1.4 Fr conductance/micromanometer catheter was placed into the left ventricle of the mice for acquisition of pressure-volume loops. Heart contractile functions were significantly decreased in the senescent group, compared with findings in the younger mice. Subsequent to ethanol treatment, the younger mice showed a significant reduction in cardiac function, with a 28% decrease in cardiac index, a 29% decrease in end-systolic elastance, and a 16% decrease in preload recruitable stroke work (P<.01). Conversely, the senescent mice showed significantly increased contractile function, with a 40% increase in end-systolic elastance (P<.01) and a 19% increase in preload recruitable stroke work (P<.05). The myocardial cyclic guanosine monophosphate levels were significantly higher in the older group (P<.002), and subsequent to ethanol treatment, they were decreased by 68.5% (P<.001). Northern blot analysis demonstrated inducible nitric oxide synthase message only in senescent myocardial tissues. Moreover, the cardiac function of senescent inducible nitric oxide synthase knockout mice was comparable with that of young mice, and after ethanol treatment, cardiac function decreased significantly, just as that for young mice did, with a 26% decrease in cardiac index (P<.05) and a 23% decrease in preload recruitable stroke work (P<.01). It was concluded that the differential cardiovascular function and response to acute ethanol

Comparison of tumor necrosis factor-alpha effect on the expression of iNOS in macrophage and cardiac myocytes

Proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), are elevated during cardiopulmonary bypass (CPB), heart failure, and inflammatory cardiac and systemic diseases. Elevated TNF-alpha has been linked to diminished cardiac function, decreased systemic vascular resistance, as well as renal and pulmonary dysfunction. It is understood that myocardial tissues can express TNF-alpha, which results in the induction of inducible nitric oxide synthase (iNOS) leading to a significant decline in cardiac function and other direct effects. The hypothesis of this study was to determine if TNF-alpha would stimulate iNOS and its product nitric oxide (NO) similarly in immortalized macrophage and cardiac myocytes. Cultured macrophages (RAW 264.7) and cardiac myocytes (HL-1) were placed into two treatment groups and a control. The treatments included: (1) TNF-alpha and lipopolysaccharide (LPS); and (2) LPS, TNF-alpha, interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) incubated for 8 h. The macrophage expression of iNOS increased by 365% (p < 0.01) and its product, NO, increased proportionally. The expression of iNOS in the cardiac myocyte did not increase with TNF-alpha and LPS. However, with the addition of IFN-alpha and IL-1beta iNOS increased to 140% of control (p < 0.05). Myocyte cGMP and NO did not increase significantly with TNF-alpha treatment. This study suggests that HL-1 myocyte iNOS cannot be induced by TNF-alpha, unlike macrophage iNOS. Furthermore, the resultant cardiac dysfunction, secondary to proinflammatory cytokines effects, is regulated via diverse pathways.

In vitro comparison of inhibitors of inducible nitric oxide synthase in a macrophage model

Nitric oxide (NO) has been shown to decrease cardiac performance, induce global hypotension, and generate oxygen free-radicals. Nitric oxide is produced from the conversion of L-arginine to L-citrulline by inducible nitric oxide synthase (iNOS) and is a component of many cellular second messenger systems. It is not clearly understood if NO and iNOS are compensatory mechanisms or pathological processes in heart failure, and this study was designed to understand better inhibition of iNOS in a cell culture model. Inhibitors of iNOS were compared for in vitro capability of inhibiting the production of NO. Ethanol and S-methylisothiourea (MITU) were applied to macrophage populations in 120 microM and 1 microM, 100 and 10 nM for an 8-h incubation. Level of iNOS expression was measured in the ethanol-treated populations using an anti-iNOS primary antibody with a fluorescent labeled secondary antibody. Serum nitrites were measured in both treatment groups by the nonenzymatic Griess method to determine enzyme function. Our data indicate that ethanol demonstrates a stimulation and simultaneous inhibition of iNOS during an 8-h incubation. No dose-dependent correlation between amount of serum nitrites produced and ethanol treatment was observed. However, MITU demonstrated a clear inhibition of iNOS at 120 microM with a serum nitrite value of 25.7002 +/- 0.0647, with control values of 24.3421 microM. Lower concentrations of MITU also demonstrated no correlation. Although both agents display inhibitory effects upon iNOS, MITU seems to have no apparent simultaneous stimulation and may hold more potential as a post-translational inhibitor of iNOS.

An epistatic interaction controls the latency of a transgene-induced mammary tumor

Previous studies from our laboratory demonstrated that the latency, tumor growth, and metastatic progression of polyoma middle T-induced mammary tumor in an FVB/NJ inbred mouse background could be significantly altered by the introduction of different genetic backgrounds. In this study we extend these findings by mapping a number of interacting quantitative trait loci responsible for the changes in phenotype. Introduction of the I/LnJ inbred genetic background into the FVB/NJ-PyMT animal significantly accelerated the appearance of the primary tumor (35 vs. 57 days postnatal, p < 10(-7)). A backcross mapping panel was established, and loci responsible for the tumor acceleration were detected on Chrs 15 and 9. Examination of the genotype/phenotype correlation revealed that the FVB/NJ but not the I/LnJ allele of the Chr 15 locus was associated with tumor acceleration and was conditional on the presence of I/LnJ allele on Chr 9. These loci, designated Apmt1 and Apmt2, map to homologous regions associated with LOH in human breast cancer. These results suggest that allelic variants of genes in these regions may contribute to age of onset in human breast cancer.

Domestic swine model for the assessment of chemical warfare agent-anesthetic interactions: some effects of sulfur mustard

A domestic swine model was developed to examine the interaction of chemical warfare agents with anesthetics and other drugs used during general anesthesia. Animals were fully instrumented, and clinically relevant physiological parameters were monitored throughout the experimental procedures. Exposure of animals under halothane anesthesia to the chemical warfare agent sulfur mustard (HD; 1 mg/kg intravenous) produced mild signs of systemic intoxication during the subsequent 5 hours. Induction doses of ketamine 1 hour after HD exposure resulted in periods of profound apnea, with continued respiratory distress for the next 2 hours. When animals were treated with HD 1 hour after the initiation of ketamine anesthesia, severe and persistent convulsion-like muscular activity was observed within 45 minutes of HD administration. This nonpurposeful activity was not ameliorated by diazepam but was dramatically reduced or eliminated by resumption of halothane anesthesia. Treatment of HD-intoxicated pigs with succinylcholine produced a prolonged apnea resulting in death. In these apparently mildly HD-intoxicated animals, the introduction of ketamine or succinylcholine can rapidly induce potentially life-threatening situations.