Effects of subprimal type, quality grade, and aging time on display color of ground beef patties.

A factorial design was used to evaluate the effects of two subprimal types (chuck roll and knuckle), two quality grades (Premium Choice and Select), and three vacuum-storage aging times before processing (7, 21, and 42d) ground beef patty display color attributes. Patties from chuck roll and Premium Choice subprimals had brighter red visual color scores, less discoloration, and higher L*, a*, b*, and chroma values than those from knuckle and Select subprimals, respectively. With an increased display time, patties became darker red, more discolored, and had decreased L*, a*, b*, and chroma values. Therefore, aging Premium Choice chuck rolls for less time (fewer than 21d) could maximize display color life.

In vitro testing of platinum-based drugs on a panel of human ovarian tumour cell lines.

Much improvement in the treatment of ovarian cancer has been achieved since the introduction of platinum compounds in the 1980s, with the result that single-agent platinum-based therapy following primary surgery is now the standard treatment for advanced ovarian cancer. The main therapeutic effect of chemotherapy is based on the sensitivity of the patient's tumour to the drug. However, testing a new chemical compound on humans requires much care, time and resources, whereas prior testing of drugs on cancer cell lines may indicate those drugs particularly suited to treatment of a specific disease. This study investigates the actions of two established platinum-based chemotherapeutic agents (cisplatin and carboplatin) on a panel of 10 human ovarian cancer cell lines. Each cell line was plated onto 96-well tissue culture plates, incubated for 72 hours with the drug, formalin-fixed and then assessed using the methylene blue colorimetric microassay to detect viable cells. The IC50 values for each cell line were calculated in order to assess the toxicity of each drug, and a wide range of responses were observed across the 10 cell lines investigated. This suggests that the panel reflected the heterogeneous nature of ovarian cancer, a malignancy in which a huge range of drug sensitivities can be seen even among tumours of the same histological type. The results indicate that the panel could be of use either as a primary screen to test new drugs against ovarian cancer or to investigate the drug resistance that is so common in this disease.

Mycoplasma detection in cell cultures: a comparison of four methods.

Mycoplasma is a common contaminant of tissue culture samples. Infection is persistent, difficult to detect and diagnose, and very difficult to cure. The concentration of mycoplasma in infected cultures can be as high as 10(7) colony-forming units per mL, and their presence can change many of the cell reactions, including altering cell growth rate, inducing morphological changes or cell transformation, and mimicking virus infection. Therefore, it should be assumed that a mycoplasma-contaminated cell line may be significantly influenced in every respect, and, thus, experimental data derived from such a cell line is likely to be invalid. Contamination is not obvious, either macroscopically or microscopically; thus, routine mycoplasma testing is essential for any cell culture laboratory. Many of the testing procedures developed so far are time-consuming, expensive, inconclusive and unsuitable for screening large numbers of test specimens. This study compares DNA staining, enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR) and PCR ELISA, to determine which is the best procedure for routine assessment of cell cultures. All four methods gave reproducible results with both infected and non-infected cell lines. Both ELISA methods were easy to perform, reproducible and easily interpreted.

Comparison of male and female nurses' attitudes toward obesity.

The Attitudes Toward Obesity Scale was administered to 23 male and 45 female caregivers and 55 patients. There were no sex differences in reported negative feelings of caregivers, but the obese patients reported significantly more negative attitudes of caregivers than did the nonobese patients.

Positron emission tomography: new hope for early detection of recurrent brain tumors.

Positron emission tomography (PET), the newest of the nuclear medicine imaging instruments, is now being used for diagnosis in 20 clinical sites in the United States. Recent approval of third-party reimbursement for PET scans for selected illnesses has set the precedence for wider clinical applications of this advanced diagnostic tool. Most practical of the newest applications of PET in the US is in early detection of recurrent brain tumors. Early detection not only saves lives, but also may save thousands of dollars in unnecessary tests, treatments, and surgeries. PET has two basic advantages over computerized tomography (CT) scans and magnetic resonance imaging (MRI). First, PET creates vastly superior images of metabolic activity, making possible more accurate and detailed diagnoses. Secondly, PET causes very low radiation absorption due to the volatile nature of the radioisotopes used. The rapidly increasing use of PET in clinical situations requires the nurse to become aware of its basic principles and applications, as well as the nursing care involved when a client is scheduled for a PET scan. This study serves to explain basic physical principles employed by PET. The historical development of PET and the comparison of PET with x-ray, CT, and MRI are reviewed. The article concludes with a discussion of future oncologic applications and the latest research developments in clinical use of PET scans.

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression and function on cultured human glomerular epithelial cells.

Glomerular epithelial cells are involved in extracapillary inflammation (crescents) but the mechanisms of this extracapillary accumulation of macrophages, epithelial cells and occasional lymphocytes are unknown. Human glomerular parietal epithelial cells express ICAM-1 and VCAM-1 on immunohistological stains of renal biopsies. We studied the expression of these cell adhesion molecules on cultured human glomerular epithelial cells (HGEC), their regulation by pro-inflammatory cytokines, and their role in mediating the adhesion of concanavalin A (Con A)-activated peripheral blood mononuclear cells. Human glomerular epithelial cells in culture constitutively express ICAM-1 and VCAM-1. The expression of ICAM-1 was not significantly altered by tumour necrosis factor-alpha (TNF-alpha) (P = 0.32), IL-1 beta (P = 0.24), interferon-gamma (IFN-gamma) (P = 0.66) or IL-4 (P = 0.85). VCAM-1 expression was increased by all four cytokines, but only significantly so by IL-4 (P = 0.0001). Con A-stimulated, monocyte-depleted peripheral blood lymphocytes bound to human glomerular epithelial cells, median 28.9% (range 14.5-37.9%). This adherence was significantly inhibited by anti-ICAM-1 (P = 0.03) and anti-LFA-1 (P = 0.02), but not by anti-VCAM-1 (P = 0.13) or by antibody to von Willebrand factor (P = NS). The interaction between ICAM-1 on HGEC and LFA-1 on mononuclear cells may be important in the pathogenesis of extracapillary inflammation in glomerulonephritis.

The effect of bile salts on human vascular endothelial cells.

The uptake and release of radiochromium from adult human vascular endothelial cells in culture was employed to determine the relative toxicity of different bile salts. Endothelial cells after pre-incubation with 51Cr for 18 h were incubated with bile salts for 24 h and percentage chromium release was taken as a measure of toxicity to cells. Lithocholic acid (LC) (potassium salt) was cytotoxic at concentrations greater than 50 microM. However, LC glucuronide, sulfate and the beta-epimer were progressively less toxic with toxicity seen at concentrations of 60, 110 and 180 microM, respectively. The greatest cytotoxic effect was observed with glycolithocholic acid (GLC) (potassium salt) which was toxic at every concentration tested (20-200 microM). Sulfation abolished the toxic effect of GLC. At the concentrations employed for the assay (between 20 and 240 microM) GLC sulfate (disodium salt), taurolithocholic acid sulfate (disodium salt), cholic acid (sodium salt), glycocholic acid (sodium salt), deoxycholic acid (sodium salt) and ursodeoxycholic acid (sodium salt) were not cytotoxic. The 51Cr release cytotoxicity assay was validated with lactate dehydrogenase leakage from endothelial cells with a good correlation (r = 0.87). These data confirm in a human cellular system that LC and its conjugates were the most toxic of the bile salts tested and explains its pathophysiological importance in hepatobiliary disease. It also suggests that biotransformation by either sulfation or beta-epimerisation of bile salts especially of LC, as occurs in patients with intrahepatic or extrahepatic biliary obstruction or severe cholestasis, is hepatoprotective.

Effects of the DNA strand-cleaving antitumor agent, streptonigrin, on ataxia telangiectasia cells.

Cells from patients with ataxia telangiectasia (A-T) were shown to be more sensitive to streptonigrin than were cells from normal individuals. A linear dose-dependent cell survival was observed for both normal and A-T cells exposed to streptonigrin (up to 1.5 ng/ml) for 3-hr, with the A-T cells being about twice as sensitive as were the normal cells (Do approximately 0.25 ng compared with Do approximately 0.5 ng). The extreme toxicity of streptonigrin is also seen in the response of DNA synthesis which is inhibited sharply in both A-T and normal cells using doses of up to 125 ng/ml, although the effect was less pronounced in A-T cells. A greater amount of time was needed for recovery of DNA synthesis in normal cells compared with that of A-T cells. Finally, chromosomes from both A-T lymphocytes and fibroblasts show about a doubling of breakage rate following exposure to streptonigrin. The increased sensitivity of A-T cells to streptonigrin appears to be fairly comparable to the sensitivity to ionizing radiation, bleomycin, or neocarzinostatin and provides further evidence that perhaps A-T cells are deficient in some form of DNA strand repair.