Antioxidants enhance the cytotoxicity of chemotherapeutic agents in colorectal cancer: a p53-independent induction of p21WAF1/CIP1 via C/EBPbeta.

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States. Five-fluorouracil (5FU) remains the single most effective treatment for advanced disease, despite a response rate of only 20%. Herein, we show that the antioxidants pyrrolidinedithiocarbamate and vitamin E induce apoptosis in CRC cells. This effect is mediated by induction of p21WAF1/CIP1, a powerful inhibitor of the cell cycle, through a mechanism involving C/EBPbeta (a member of the CCAAT/enhancer binding protein family of transcription factors), independent of p53. Antioxidants significantly enhance CRC tumor growth inhibition by cytotoxic chemotherapy in vitro (5FU and doxorubicin) and in vivo (5FU). Thus, chemotherapeutic agents administered in the presence of antioxidants may provide a novel therapy for colorectal cancer.

Role of pictorial cues in young children's distinguishing self-performed from self-imagined actions.

32 4- and 5-yr.-olds participated in a series of performed and imagined actions and a memory interview. Children in the Picture condition answered questions accompanied by pictures of actions whereas children in the Verbal condition received only the verbal cues. Children in the Picture condition performed as well as children in the Verbal condition when classifying performed and new actions but had more difficulty classifying imagined actions. Results suggest that retrieval cues (pictures) did not enhance children's discrimination of self-performed and self-imagined actions.

Decreased transforming growth factor beta type II receptor expression in intestinal adenomas from Min/+ mice is associated with increased cyclin D1 and cyclin-dependent kinase 4 expression.

Tumor cells often become resistant to the growth-inhibitory effects of transforming growth factor beta (TGF-beta). Recent studies have identified TGF-beta type II receptor (RII) mutations in a subset of cancers, including colon cancer. To evaluate the expression of TGF-beta RII in premalignant intestinal adenomas and the relationship with cell cycle regulation, we investigated the expression of TGF-beta RII, cyclin D1, and cyclin-dependent kinase 4 (Cdk4) in Min/+ mouse intestinal adenomas. Immunohistochemistry indicated that TGF-beta RII cytoplasmic immunoreactivity was undetectable in the proliferative crypt zones of the normal small intestinal and normal colonic epithelium but was abundant toward the villus tips of the normal small intestine and the lumenal third of the colonic glands. As was observed in the proliferating crypt zones, TGF-beta RII immunoreactivity was dramatically decreased or undetectable in all adenomas examined in comparison to the abundant levels in adjacent normal differentiated intestinal epithelium. TGF-beta RII mRNA was also reduced in the adenomas in comparison to normal mucosa as determined by reverse transcription-PCR. In an inverse distribution to TGF-beta RII, Cdk4 nuclear immunoreactivity was restricted to the crypt regions of the small and large intestine, whereas cyclin D1 immunoreactivity was uniformly absent in normal intestinal epithelium. For both cyclin D1 and Cdk4, protein and mRNA levels were increased in intestinal adenomas but not in normal intestinal epithelium as determined by immunohistochemistry, in situ hybridization, and reverse transcription-PCR. In summary, the lack of TGF-beta RII expression was associated with increased cyclin D1 and Cdk4 expression in Min/+ mouse intestinal adenomas. We hypothesize that the former may enable tumor cells to escape from the normal growth-constraining influence of TGF-beta, whereas the latter promotes inappropriate cell proliferation and adenoma progression.

Sea urchin maternal mRNA classes with distinct development regulation.

Previous studies of newly synthesized proteins during early development in sea urchins have revealed several different patterns of synthesis that can be used to predict the existence of mRNA classes with distinct regulatory controls. We have identified clones for abundant maternal mRNAs that are actively translated during early development by screening a cDNA library prepared from polysomal poly(A)+RNA isolated from 2-cell stage (2-hour) Strongylocentrotus purpuratus embryos. Probes prepared from these cDNA clones and several previously characterized maternal mRNA cDNAs were used to compare relative levels of individual mRNAs in eggs and embryos and their translational status at various developmental stages. These abundant mRNAs can be classified into two major groups which we have termed cleavage stage-specific (CSS) and post cleavage stage (PCS) mRNAs. The relative levels of the CSS mRNAs are highest during the rapid cleavage stage and decrease dramatically at the blastula stage (12-hours). In contrast, PCS mRNAs are present at relatively low levels during the rapid cleavage stage and then increase at the blastula stage. Polysome partition profiles reveal that CSS mRNAs are translated more efficiently than PCS mRNAs in the unfertilized egg, at fertilization, and during the cleavage stages. Following the blastula stage, some CSS transcripts move out of polysomes and accumulate as untranslated RNAs, while newly transcribed PCS mRNAs are recruited into polysomes. These data suggest that the rapid cell cycles following fertilization require high levels of specific cleavage stage proteins, and the synthesis of these proteins occurs preferentially over PCS mRNAs.

The impact of specific toy warning labels.

According to the 1980 Consumer Product Safety Commission's small parts standard, toys with small parts that pose a choking hazard cannot be marketed for children under the age of 3 years. To comply with the standard, toy manufacturers place age labels on packaging to indicate the ages for which toys with small parts are recommended. We conducted a survey of 199 toy buyers to determine the degree to which they understood such labels as warnings and whether more explicit warning labels would affect toy buyers' willingness to purchase toys with small parts for children between 2 and 3 years of age. Forty-four percent of respondents said they would buy for a child between 2 and 3 years of age a toy with the label "Recommended for 3 and up"; only 5% said they would buy for a young child a toy with the label "Not recommended for below 3--small parts." These findings indicate that a change in the small parts standard to require more specific labeling might substantially reduce potentially hazardous toy purchases.

Counterproductive transcriptional and translational regulation of elongation factor 1-alpha synthesis during early development in sea urchins.

We have isolated a cDNA clone encoding elongation factor 1-alpha (EF1-alpha) and used probes prepared from this cDNA to measure levels of EF1-alpha transcripts during early development. We also determined the fraction of EF1-alpha transcripts in polysomes during this time period. Following the blastula stage there is a sharp increase in the amount of EF1-alpha mRNA. This pattern of accumulation is similar to other previously described sea urchin mRNAs. However, while the level of EF1-alpha mRNA is increasing, the fraction of EF1-alpha mRNA in polysomes decreases. Thus, there is an apparently counter-productive decrease in efficiency of recruitment into polysomes occurring concurrently with an increase in the overall amount of EF1-alpha mRNA.

Neurohumoral modulation of the pulmonary vasoconstrictor response in the autoperfused working heart-lung preparation during cardiopulmonary preservation.

Uncontrolled pulmonary hypertension during autoperfusion of the heart and lungs for preservation has been described, and it may result in extensive pulmonary injury and occasional early failure of the preparation. In order to investigate the neurohumoral mediators of the vasoconstrictor response in the pulmonary circulation of the autoperfused working heart-lung preparation, heart-lung organ blocks were harvested from calves, placed in a normothermic autoperfusion circuit, and studied. Effects of beta-adrenergic stimulation with isoproterenol, nonspecific vasodilatation with nitroglycerin, alpha-adrenergic blockade with phentolamine, phospholipase A2 inhibition with methylprednisolone, cyclooxygenase inhibition with indomethacin, and white blood cell depletion were independently evaluated. Untreated animals, pre- and postexplant, served as controls. Multipoint pulmonary vascular pressure-cardiac output plots were constructed for each animal. An index of pulmonary vascular resistance was obtained from the linear relation: mean pulmonary artery pressure minus pulmonary capillary wedge pressure divided by cardiac output. An intense flow-dependent pulmonary vasoconstrictor response was confirmed to exist in the denervated bovine autoperfused working heart-lung preparation. Isoproterenol afforded better protection against this response than the other agents studied. White blood cell depletion reduced postexplant pulmonary vasoconstriction, implying that circulating polymorphonuclear leukocytes mediate the response in the autoperfused working heart-lung preparation. White blood cell depletion and the administration of selected pharmacologic agents provide modalities for regulating the pulmonary vasoconstrictor response, and thus may enhance lung preservation in the autoperfusion model.

Stage-specific expression of beta-1, 3-glucanase in sea urchin embryos and hybrids.

In some species of sea urchin, such as Lytechinus variegatus beta-1, 3-glucanase activity is present at two distinct developmental stages (in the unfertilized egg and again following gastrulation). There is a different form of the enzyme beta-1, 3-glucanase specific to each stage, and these forms can be distinguished immunologically and biochemically. The distinguishing characteristics of the egg and embryonic enzymes were used to analyze the forms of beta-1, 3-glucanase present in other species that express activity at only one of the two stages. The enzyme present in Tripneustes esculentes, which has activity only early in development, is an 80,000 dalton enzyme antigenically similar to the egg enzyme in Lytechinus. The enzyme present following gastrulation in Echinometra lucunter, however, is distinct from the egg enzyme and is similar to the embryonic enzyme in Lytechinus, despite the absence of activity in the eggs of Echinometra. These results indicate the two forms of beta-1, 3-glucanase (egg and embryonic) are expressed independently and in a stage-specific manner, suggesting they are not functionally equivalent. beta-1, 3-glucanase activity was also analyzed in interspecific hybrids. Tripneustes esculentes (which normally lacks the embryonic form) suppressed the expression of the embryonic enzyme in crosses with Lytechinus variegatus (which normally does express it). This suppression occurred whether the Tripneustes genetic material was maternal or paternal in origin. However, the embryonic enzyme normally expressed by Echinometra was expressed in crosses of this species with Tripneustes, i.e, Tripneustes did not suppress enzyme expression in these hybrids.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of early onset of otitis media on educational achievement.

One hundred and forty-four patients from three different pediatric practices were compared using the Science Research Associates (SRA) tests for academic achievement. First, the patients were divided into those who had had three or more attacks of otitis media and those who had had no attacks of otitis media during the first 18 months of life as recorded by their pediatricians. Matched pairs by sex, birth date, occupation of father, school attended and year of testing were made for comparison purposes. Using the one-tailed t-test, a significant difference in the composite score was found favoring the group with no recorded otitis media in the first 18 months of life. All patients were treated with antibiotics.