Enhanced myocardial necrosis induced in rats by the combined administration of hydralazine and prenalterol

The cardiotoxic effects of hydralazine and prenalterol, given alone and in combination, were assessed in rats and rabbits. Acute myocardial necrosis was induced by a single administration of each drug alone in rats. However, the incidence and severity of lesions were markedly enhanced when both drugs were given in combination. Rats that received the same treatment for 10 consecutive days showed minimal or no acute necrosis, demonstrating the development of a resistance to further cardiotoxic effects of the drugs. Rabbits showed only minimal lesions when either drug was used alone and no enhancement of lesions when they were given in combination. From these data, it is concluded that the possibility of a cardiotoxic interaction exists when these drugs are used in combination and that the heavy rat (500-600 g) is a more sensitive model than the rabbit for studies of this nature.     

Loss of breast cancer metastasis suppressor 1 protein expression predicts reduced disease-free survival in subsets of breast cancer patients.

PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors.     

Trends in Folic Acid Awareness and Behavior in the United States: The Gallup Organization for the March of Dimes Foundation Surveys, 1995–2005

Objective: To summarize changes in folic acid awareness, knowledge, and behavior among women of childbearing age in the United States since the U.S. Public Health Service (USPHS) 1992 folic acid recommendation and later fortification. Methods: Random-digit dialed telephone surveys were conducted of approximately 2000 women (per survey year) aged 18–45 years from 1995–2005 in the United States. Results: The percentage of women reporting having heard or read about folic acid steadily increased from 52% in 1995 to 84% in 2005. Of all women surveyed in 2005, 19% knew folic acid prevented birth defects, an increase from 4% in 1995. The proportion of women who reported learning about folic acid from health care providers increased from 13% in 1995 to 26% in 2005. The proportion of all women who reported taking a vitamin supplement containing folic acid increased slightly from 28% in 1995 to 33% in 2005. Among women who were not pregnant at the time of the survey in 2005, 31% reported taking a vitamin containing folic acid daily compared with 25% in 1995. Conclusions: The percentage of women taking folic acid daily has increased modestly since 1995. Despite this increase, the data show that the majority of women of childbearing age still do not take a vitamin containing folic acid daily. Health care providers and maternal child health professionals must continue to promote preconceptional health among all women of childbearing age, and encourage them to take a vitamin containing folic acid daily.

     

A Comparison of Oral and Rectal Absorption of L-Dopa Esters in Rats and Mice

Short-chain alkyl esters of L-dopa were administered to rats and mice via oral and rectal routes. Plasma L-dopa esters and L-dopa were determined in the systemic and portal circulation by HPLC. A comparison of isopropyl, butyl, and 4-hydroxybutyl esters of L-dopa demonstrated significantly higher levels of the esters in both systemic and portal blood samples following rectal administration than following oral administration. In most cases, oral administration resulted in nondetectable (<0.01 µg/ml) levels of the esters in plasma. Correspondingly, the plasma levels of L-dopa itself were consistently higher following rectal administration. At very high oral doses (500 mg L-dopa equivalents/kg body weight), systemic plasma levels of the butyl ester could be detected (1.25 µg/ml at 10 min), which might indicate saturation of the esterase activity of the small intestine. These studies indicate that the systemic availability of L-dopa from short-chain alkyl esters of L-dopa may be best optimized by rectal administration, which avoids the relatively high esterase activity characteristic of the small intestine.     

In VivoStudies of Adenovirus-Based p53 Gene Therapy for Ovarian Cancer

Objectives.To test the safety, efficacy, and toxicity of gene therapy using wild-type p53-expressing adenovirus (Ad-CMV-p53) in a nude mouse model with intraperitoneal (ip) 2774 human ovarian cancer cell line that contains a p53 mutation.Study design.An initial study of adenovirus tolerance was determined in nude mice by a single ip injection of increasing doses of Ad-CMV-p53. Nude mice were implanted with an LD₁₀₀dose of 1 × 10⁷cells. To study the efficacy and specificity of Ad-CMV-p53 treatment, the mice received treatment with different adenovirus constructs. One group received Ad-CMV-p53 and another group received a control adenovirus construct, Ad-CMV-βgal. To study the treatment response to Ad-CMV-p53, the mice were divided into groups and received various treatment schedules of 1 × 10⁸pfu of Ad-CMV-p53.Results.The mice tolerated Ad-CMV-p53 without adverse effects at doses of 1 × 10⁸pfu. The response to Ad-CMV-p53 showed significant survival duration in each dose regimen, with a survival time greater than that of untreated animals (P= 0.0173). However, no statistically significant survival advantage was observed between Ad-CMV-p53- and Ad-CMV-βgal-treated mice.Conclusions.These studies show that at the adenovirus dose and administration regimen used, there is effective but not specific 2774 tumor growth inhibitionin vivo.Efficient introduction of biologically active genes into tumor cells would greatly facilitate cancer therapy. Thus, although promising, these results caution that much effort will be required to realize the potential for clinical application of adenovirus-based ovarian cancer gene therapy.     

Stimulus functions of drugs and the assessment of abuse liability

The development of a unifying framework for conceptualizing the commonalities in various forms of substance abuse must encompass the data base focused upon the stimulus functions of drugs. In the first instance, for example, the research on drug self-administration has provided convincing evidence of a remarkable concordance between laboratory animals and human substance abusers in the reinforcing stimulus functions of a range of chemical agents. The recognition of these cross-species and cross-drug generalities has radically changed conceptualizations of substance abuse from a reactive to a more active process and has encouraged the kind of functional analysis of drug-seeking and drug-taking that has proven productive and useful in the study of other behavioral interactions. In this regard as well, recent refinements in the analysis of the discriminative stimulus functions of drugs have provided a more comprehensive basis for characterizing a chemical agent's spectrum of action and evaluating its abuse liability. While the correlation between the discriminative stimulus functions and the reinforcing stimulus functions is remarkably high for some drug classes, there are notable exceptions. Finally, the assessment of abuse liability requires an analysis of the eliciting stimulus functions of drugs as reflected by the physiological and behavioral changes, both acute and chronic, that follow drug administration. The methods used to evaluate both physiological dependence and behavioral toxicity in relationship to sensory and motor effects for a range of abused drugs have depended heavily upon an assessment of the eliciting stimulus functions of such compounds.     

Development of intestinal epithelial cell lines using a transgenic mouse

The epithelial cells of the colonic mucosa of the animal have proved impossible to culture using standard tissue culture techniques. Immortalization of adult colonic epithelial cells has been unsuccessful due to the lack of DNA synthesis in these cells once they are isolated from the tissue. Recently an unique transgenic mouse bearing a temperature sensitive mutant of the known immortalizing gene, SV40 large T has become available. The advantage of this mouse is that the SV40 large T gene is expressed in every cell. Active immortalizing protein is produced in each cell at the permissive temperature. We have used colonic mucosa from these mice to initiate cultures of epithelial cells from the colon of adult mice. The cells grow readily at the permissive temperature but die within 7 days at the non-permissive temperature. The methods used to develop these cultures are described.