Evaluation of in vitro cytotoxicity of nonsteroidal anti-inflammatory drugs against canine tumor cells

Piroxicam and other nonsteroidal anti-inflammatory drugs (NSAID) have antitumor activity against naturally acquired cancer in dogs and human beings, and against experimentally induced tumors in rodents. We are investigating potential mechanisms of NSAID antitumor activity. The direct cytotoxicity of piroxicam indomethacin, and aspirin against 4 canine tumor cell lines (transitional cell carcinoma, squamous cell carcinoma, melanoma, and soft tissue sarcoma) was determined in short-term growth rate assays and in clonogenic assays. Piroxicam was evaluated alone and in combination with the lipoxygenase inhibitor zileuton, and in combination with the chemotherapeutic agents cisplatin and carboplatin. The 50% inhibitory concentrations (IC50) against melanoma cells in short-term growth rate assays were: 530 microM piroxicam, 180 microM indomethacin, and greater than 1 mM aspirin. These IC50 values were over 10 times greater than serum concentrations of these drugs that could safely be achieved in vivo. The IC50 of zileuton combined with piroxicam (280 microM) was not different from the IC50 of zileuton alone (230 microM; ANOVA P = 0.47) in melanoma cells. Similarly, addition of piroxicam did not alter the IC50 of either cisplatin (1.6 microM) or carboplatin (6.1 microM). These results suggest that NSAID, at serum concentrations achievable in vivo, do not have direct cytotoxicity against canine tumor cells tested. It is unlikely that the in vivo antitumor activity of NSAID is attributable to a direct cytotoxic effect.

Low density lipoprotein receptors in rat adipose cells: subcellular localization and regulation by insulin

The distribution of LDL receptors within subcellular compartments of isolated rat adipose cells and the effects of insulin on their expression have been assessed. By immunoblotting with specific anti-rat LDL receptor antibodies, LDL receptors were 2.3- and 4.5-fold enriched in endoplasmic reticulum-rich high-density microsomes (HDM) and Golgi complex-rich low-density microsomes (LDM), respectively, compared to plasma membranes (PM). This distribution was similar in cultured cells in which total receptors were increased 2.5-fold compared to freshly isolated cells. After correction for enzyme recoveries, LDL receptors were distributed approximately 4% in HDM, approximately 73% in LDM, and approximately 23% in PM. Insulin decreased total LDL receptors in adipose cells approximately 44%, with a 48% and 49% decrease in HDM and LDM, respectively, without any changes in PM. In contrast, insulin caused an increase of glucose transporters in PM while also decreasing glucose transporters in LDM. When adipose cells were depleted of potassium to inhibit receptor-mediated endocytosis, insulin again caused a decrease of LDL receptors in LDM but now increased LDL receptors in PM. Insulin increased the rate of LDL receptor synthesis approximately 24%, but decreased their half life approximately 40%. Thus, in isolated adipose cells the majority of LDL receptors appear to be located in an intracellular compartment that co-sediments with the Golgi complex rather than located in the PM. The LDL receptors localized in intracellular compartments seem to be functionally regulated as insulin acutely diminishes the number of receptors by apparently accelerating their rate of degradation through, as yet, incompletely determined mechanisms.

Aggregating social behavior into person models: perceiver-induced consistency

Two experiments explored the role of perceivers (judges) in aggregating social behavior into impressions. In Experiment 1, it was predicted and found that judges influence impressions (i.e., eye-of-the-beholder effects) not only because they disagree on how to interpret single acts but because they aggregate multiple acts in unique ways to arrive at idiosyncratic impressions. Using D. A. Kenny's (1991) general model of accuracy and consensus, it was found that judges perceived much greater consistency in the behavior of targets across situations when they were asked to aggregate the behavior than when they were not. Differential interpretation of single acts did not change as a function of aggregating behavior. This aggregation process was characterized as the construction of models of persons. In Experiment 2, the concept of person models was explored further, and it was argued that perceivers develop these models on the basis of what is viewed as the central concept of a target. For any given target, a limited number of models can be identified, and different perceivers develop different models. The particular model formed has implications for the perceiver's underlying memory representation and the perceived personality profile of the target.

Aggregating social behavior into person models: perceiver-induced consistency

Two experiments explored the role of perceivers (judges) in aggregating social behavior into impressions. In Experiment 1, it was predicted and found that judges influence impressions (i.e., eye-of-the-beholder effects) not only because they disagree on how to interpret single acts but because they aggregate multiple acts in unique ways to arrive at idiosyncratic impressions. Using D. A. Kenny's (1991) general model of accuracy and consensus, it was found that judges perceived much greater consistency in the behavior of targets across situations when they were asked to aggregate the behavior than when they were not. Differential interpretation of single acts did not change as a function of aggregating behavior. This aggregation process was characterized as the construction of models of persons. In Experiment 2, the concept of person models was explored further, and it was argued that perceivers develop these models on the basis of what is viewed as the central concept of a target. For any given target, a limited number of models can be identified, and different perceivers develop different models. The particular model formed has implications for the perceiver's underlying memory representation and the perceived personality profile of the target.

Measuring intramuscular fat in beef with ultrasonic frequency analysis

Frequency analysis of Fourier spectra from ultrasonic signals was used for predicting intramuscular fat content of beef tissue. The most significant parameter in the frequency domain for predicting intramuscular fat concentration in beef was the number of local maxima. It represents the discontinuity of the Fourier spectrum caused by inhomogeneous fat concentrations in the longissimus muscle, which had the correlation coefficient .89 (P < .05) when a 2.25-MHz shear probe was used. The optimum frequency for predicting the amount of intramuscular fat content in the longissimus muscle was found to be 1.92 MHz. A multivariate regression model was developed using parameters in the frequency domain as follows: percentage of fat concentration = 1.790 - 2.373x (lower frequency) + .049x (bandwidth) + 1.178x (local maxima) (R2 = .82). Validation demonstrated that the multivariate model in the frequency domain was capable of predicting intramuscular fat concentration with an average of 1.17 percentage of fat error (P < .05). The multivariate model was most appropriate for predicting intramuscular fat below 4%. The mean accuracy of the model in the frequency domain was approximately 79%.

Predicting intramuscular fat in beef longissimus muscle from speed of sound

The ultrasonic A-mode method was investigated for intramuscular fat measurement of beef. Cubes of meat samples that had different marbling scores were used as specimens. Ultrasonic speed decreased with increasing fat concentration. The correlation coefficient was -.82 (P < .05). Conversely, the correlation coefficient between visual marbling score and fat concentration was .70 (P < .05). Quantitatively, from the first derivative of a nonlinear function, it was concluded that the speed decreased at a rate of 2.69 m/(s-% fat) as a function of intramuscular fat. A nonlinear regression model to predict intramuscular fat content in beef was developed as follows: percentage of fat concentration = 7132.1574-9.1222 x (speed) + 2.91803 x 10(-3) x (speed)2 (R2 = .81). The nonlinear model was capable of predicting intramuscular fat concentration with 90% accuracy (> 8% fat) and 76.4% accuracy (< 8% fat), respectively (P < .001).

Low-density lipoprotein receptors in rat adipocytes: regulation with fasting

Adipose tissue metabolism is exquisitely sensitive to caloric intake. With increasing adiposity more triglyceride and cholesterol are stored within increasingly large adipocytes, whereas less triglyceride and cholesterol are stored as the size of the fat cell decreases. A portion of the uptake of cholesterol by adipocytes is mediated by low-density lipoprotein (LDL) receptors. The present studies addressed whether LDL receptors are differentially regulated in adipose tissue and the liver during fasting in the rat. Two days of fasting caused a reduction in body weight with an approximately 40% decrease in the epididymal fat depot and fat cell size. No changes in serum cholesterol were noted, but serum triglycerides fell approximately 55% with fasting. LDL receptors detected by immunoblotting decreased progressively with fasting to levels that were 95% below controls in adipocytes isolated from epididymal fat pads by 2-3 days. In contrast, hepatic LDL receptor expression was unaltered by fasting. After 2 days of fasting, the rate of synthesis of LDL receptors in isolated adipose cells was decreased approximately 35%, whereas levels of LDL receptor mRNA were diminished approximately 55%. It is concluded that the expression of LDL receptors in rat adipocytes is markedly downregulated during fasting through transcriptional and posttranscriptional mechanisms. Furthermore, LDL receptor expression is differentially regulated in adipose tissue and liver during fasting in the rat.

Definition and assessment of accuracy in social stereotypes

A perennial issue in the study of social stereotypes concerns their accuracy. Yet, there is no clear concept of the various ways in which stereotypes may be accurate or inaccurate and how one would assess their accuracy. This article is designed to rectify this situation. Three forms of stereotype inaccuracy are identified: stereotypic inaccuracy, valence inaccuracy, and dispersion inaccuracy. The implications of each form are discussed, along with how each can be assessed using a full-accuracy design. Past research that has attempted to examine stereotype accuracy is reviewed, and new data on the issue are presented. Although of perennial interest, the theoretical and methodological difficulties of assessing stereotype accuracy are substantial. The goal in this article is to alert the researcher to these difficulties and point toward their solution.

Principles of ultrasound and measurement of intramuscular fat

A review of basic engineering concepts of ultrasound is presented for the layperson with implications toward the use of ultrasound on beef animals. The use of ultrasound for determining quality traits such as percentage of intramuscular fat is discussed in detail. Results of both A-mode and B-mode preliminary investigations are presented. Preliminary results show that intramuscular fat may be predicted using an A-mode transducer coupled with frequency analysis.

Role of meaningful subgroups in explaining differences in perceived variability for in-groups and out-groups

Five aspects of the complexity of the knowledge representation of business and engineering majors were examined to see whether these differed by group membership and whether these differences were related to differences in perceived variability. Significantly more subgroups were generated when describing the in-group than the out-group; this difference predicted the relative tendency to see the in-group as more variable, and when controlled for statistically, out-group homogeneity effects were eliminated. Familiarity, redundancy, number of attributes used to describe the group, and the deviance of the subgroups from the larger group generally showed differences for in-group and out-group but did not show consistent evidence of mediation. In a 2nd study, Ss who were asked to sort group members into meaningful subgroups perceived greater variability relative to those who did not perform the sorting task.

Accuracy in the judgment of in-group and out-group variability

The accuracy of in-group and out-group variability judgments was examined by comparing those judgments with the variability of self-ratings provided by random samples of group members. Following Park and Judd (1990), perceptions of both group dispersion and group stereotypicality were examined. Accuracy was examined both by within-subject sensitivity correlations and by simple discrepancies between perceived and actual variability estimates. In-group-out-group differences in sensitivity were shown, particularly for judgments of stereotypicality. These differences were related to differences in the degree to which out-group variability is underestimated relative to in-group variability (i.e., the out-group homogeneity effect). Out-group stereotypicality judgments were overestimated, supporting the view that out-group stereotypes are overgeneralizations. Whether dispersion judgments were over- or underestimated depended on their measurement.

Accuracy in the judgment of in-group and out-group variability

The accuracy of in-group and out-group variability judgments was examined by comparing those judgments with the variability of self-ratings provided by random samples of group members. Following Park and Judd (1990), perceptions of both group dispersion and group stereotypicality were examined. Accuracy was examined both by within-subject sensitivity correlations and by simple discrepancies between perceived and actual variability estimates. In-group-out-group differences in sensitivity were shown, particularly for judgments of stereotypicality. These differences were related to differences in the degree to which out-group variability is underestimated relative to in-group variability (i.e., the out-group homogeneity effect). Out-group stereotypicality judgments were overestimated, supporting the view that out-group stereotypes are overgeneralizations. Whether dispersion judgments were over- or underestimated depended on their measurement.

Serum antibodies to cow's milk proteins in pediatric inflammatory bowel disease. Crohn's disease versus ulcerative colitis

Serum antibodies to five cow's milk proteins (alpha-casein, bovine serum albumin, beta-lactoglobulin A and B, and alpha-lactalbumin) were investigated in young patients with inflammatory bowel disease (56 Crohn's disease, 24 ulcerative colitis). IgG antibodies against bovine serum albumin, beta-lactoglobulin A and beta-lactoglobulin B were higher in Crohn's disease patients than in those with ulcerative colitis or the controls. IgG anti-bovine serum albumin antibodies were higher in those Crohn's disease patients who had higher scores of disease activity. Finally, IgA antibodies to alpha-casein were higher in patients with Crohn's disease and ulcerative colitis when compared to controls. These findings may be due to increased uptake of dietary antigens or enhanced immunological response occurring in Crohn's disease patients.

Serum antibodies to cow's milk proteins in pediatric inflammatory bowel disease: Crohn's disease vs. ulcerative colitis

Serum antibodies to five cow's milk proteins, alpha-casein, bovine serum albumin (BSA), beta-lactoglobulin A and B (BLG-a, BLG-b) and alpha-lactalbumin (ALA) were investigated in young patients with inflammatory bowel disease, 56 with Crohn's disease (CD), 24 with ulcerative colitis (UC). IgG antibodies against BSA and BLG-a and -b were higher in Crohn's disease patients as compared to those with ulcerative colitis and controls. The IgG anti-BSA were higher in the group of CD patients with higher score of disease activity. Additionally, IgA antibodies to alpha-casein were higher in CD and UC compared to control. These findings may be due to increased uptake of dietary antigens or enhanced immunological response occurring in CD patients.

Immunological aspects in patients with chronic active hepatitis--cellular immune responses

We studied host immune parameters which might be related to the activity and the pathogenetic mechanism of chronic active hepatitis. The subjects consisted of 45 cases with hepatitis B virus surface antigen (HBsAg)-positive chronic active hepatitis (CAH), 44 HBsAg-negative CAH, 22 with inactive chronic hepatitis, and 45 cases of normal persons, hepatitis B virus (HBV) carriers, or the patients with acute myocardial infarction. The in vitro assay for the in vivo activated lymphocytes was performed by measuring spontaneous thymidine uptake (SLT) of lymphocytes isolated from peripheral blood. SLT was significantly (p < 0.001) elevated in cases with HBsAg-positive (1227 +/- 806 cpm) and-negative CAH (1017 +/- 559 cpm) compared to the patients with inactive chronic hepatitis (347 +/- 79 cpm) and to the control group (320 +/- 106 cpm). SLT values observed in 7 cases with active disease (group I and II), in which remission and relapsing phase could be assessable, were elevated from 648 +/- 121 cpm in remission phase to 1548 +/- 606 cpm one to two weeks before the appearance of biochemical evidence (SGPT) of relapse. This pattern of SLT elevation, however, was not observed in patients with inactive hepatitis. Neither the abnormal distribution of T-cell subsets nor the presence of conventional HBV markers were related to the elevated SLT value. Our findings may therefore indicate that SLT might be useful in assessment of the disease activity in patients with CAH.(ABSTRACT TRUNCATED AT 250 WORDS)