Development and characterization of hydrogen peroxide-resistant Chinese hamster ovary cell variants--I. Relationship between catalase activity and the induction/stability of the oxidant-resistant phenotype

Hydrogen peroxide (H2O2)-resistant sublines of Chinese hamster ovary (CHO) cells were isolated by in vitro exposure to the oxidant (treatment for 1 hr followed by 3 days of growth in peroxide-free medium). Stepwise increase in low level H2O2 concentrations produced variants which were progressively more resistant to the growth inhibitory effect elicited by the oxidant. Removal from H2O2 decreased resistance and the curve describing this process was biphasic in nature. In addition, the rate of loss of the H2O2-resistant phenotype was more rapid for the toxicity elicited by low concentrations of hydrogen peroxide, compared to that produced by high concentrations. Changes in total cell proteins were found to parallel the variations in sensitivity to the oxidant, since the protein content constantly increased during the adaptation process and decreases upon removal from H2O2. Catalase activity did not show large variations in resistant sublines with respect to the parental cell line, and these changes were at least partially related to differences in cell size/amount of total cell proteins of the sublines. In addition, the minor changes observed for catalase activity did not correlate with the degree of resistance to growth inhibition elicited by the oxidant. It may therefore be suggested that the H2O2-resistant phenotype of mammalian cells, initially adapted to low--then gradually increased--concentrations of the oxidant, is the result of a complex phenomenon which only partially involves over-expression of catalase.

Lipid-associated sialic acid levels in human breast cyst fluids

Benign mammary gross cystic disease is the most common breast lesion. Women with apocrine changes of epithelium lining the cysts are at higher risk for developing breast cancer than the normal female population. Sialic acid has drawn considerable interest because of carbohydrate aberrations in malignant cells. The current investigation determined the concentrations of lipid-associated sialic acid (LASA) in 62 breast cyst fluids and sera. Data analyses show a significant increase in the mean values of LASA in metabolically active apocrine cysts when compared to the cysts with Na+/K+ > 3 (flattened cysts) (p < 0.001). The greater LASA levels in cyst fluids with lower intracystic Na+/K+ ratios could represent an altered expression of biosynthetic activity of the surrounding apocrine cell surface sialoglycolipid metabolism, providing a possible explanation of why women with apocrine cysts may be at greater cancer risk and being useful in further studies on functional stage changes in the cysts and their relationship to breast cancer.

[Purification from goat antiserum of immunoglobulins against G6PD from rabbits]

DEAE Affi-Gel Blue (Bio-Rad) provides an efficient and rapid fractionation of human serum proteins by a single chromatographic step. When goat serum is applied to the matrix and chromatography is performed following the procedure utilized for the human serum proteins, the elution pattern changes and the Ig purification is not satisfactory. We achieved a better Ig purification from goat serum by the following improved procedure. We performed first an AS-40 fractionation followed by extensive dialysis in 50 mM Na-citrate pH 5.7. The sample was then loaded onto a P11 column equilibrated in the same buffer. The fraction eluted at Vo contained total IgG and the other serum proteins, except beta-globulins which were eluted with 0.24 M phosphate. Peak 1 concentrated and dialyzed in 20 mM phosphate buffer pH 8 was then applied to a DEAE Affi-Gel Blue column, equilibrated in the same buffer. Two protein peaks were eluted from this column and electrophoretically characterized as: peak 1, containing a pure Ig fraction (70% yield), peak 2 with albumin and other contaminating serum proteins. When goat antiserum is obtained against a specific protein, our technique may be suitably employed to purify polyclonal antibodies for immunoprecipitation studies.

Ferritin and transferrin levels in human breast cyst fluids: relationship with intracystic electrolyte concentrations

The concentrations of sodium and potassium and the content of ferritin and transferrin, proteins considered as potential markers for identifying cells undergoing divisional activity, were measured in fluid from 30 human breast cysts. On the basis of the relative electrolyte concentrations, two main classes of cysts were defined. When the cyst fluids were subdivided according to their Na+/K+ ratio, a significant difference was found between menstruating vs. menopausal patients. The relationship between the two major iron-binding proteins and the Na+/K+ ratio may indicate the expression of a local higher biosynthetic activity in apocrine cysts associated with higher cancer risk.

[Specific enzymatic amplification of a DNA region closely associated with Huntington chorea]

Enzymatic DNA amplification has become a new important tool in the analysis of human genome. We report the use of this new technique for the detection of a polymorphic DNA sequence adjacent to the Huntington's disease locus for presymptomatic and prenatal testing of the disease.

Lactate dehydrogenase, isoenzyme patterns and cation levels in human breast gross cyst fluid

In order to investigate the diagnostic and/or prognostic value of total activity and isoenzymatic patterns of lactate dehydrogenase, 24 human breast gross cystic fluids were studied. A comparison of total lactate dehydrogenase activity to the serum level revealed an increased activity in about 63% of the cases examined; moreover, a significant increase in the slow-moving lactate dehydrogenase 4 and 5 isoenzymes was observed in some cyst fluids. The levels of Na+ and K+ concentrations were also analyzed and two classes of cysts were identified: one presenting Na+ and K+ levels similar to those found in extracellular compartment; the other with high K+ and low Na+ levels, characteristic of an intracellular fluid. This latter pattern could indicate an active metabolism of the epithelial cells lining the cysts. This breast cyst fluid also showed increased levels of lactate dehydrogenase 4 and 5 isoenzymes. The correlation between an increased activity of lactate dehydrogenase 4 and 5 isoenzymes and high K+ and low Na+ levels could be the expression of a high biosynthetic activity and of an anaerobic metabolism in some cysts, suggesting the evolution of the breast gross cyst lesion to malignancy. The importance of these observations is discussed.

[Carcinoembryonic antigen in a review of cases in the literature]

Literature analysis of CEA serum levels tested in 21,147 patients, with non neoplastic and neoplastic disease of various organs, are reported. The sensitivity, the specificity, the positive and negative prognostic trend and the effective value of test in different pathologic situations are evaluated on the basis of organ localization and embryological origin.

Alkaline phosphatase expression in human chorionic villi

The physicochemical properties and electrophoretic mobility of different isoforms of alkaline phosphatase were studied in chorionic villi. Based on selective inactivation and inhibition studies (thermal stability, inactivation by urea, EDTA and L(+)ascorbic acid and L-amino acid inhibition), evidence was obtained for the existence of two distinct types of alkaline phosphatase in trophoblast cells. One type is peculiar to chorionic villi while the other is also found in term placenta. Both show two isoforms. These two isoforms were observed with polyacrylamide gel electrophoresis, carried out at pH 6.0 and 9.5. It is suggested that the qualitative and quantitative methods of alkaline phosphatase analysis could be used for first trimester fetal diagnosis of severe infantile hypophosphatasia and for understanding genetic control during early fetal development.

Hydroxyproline and creatinine levels in normal amniotic fluid

Total hydroxyproline and creatinine concentrations as well as their ratios were determined in 29 amniotic fluid samples from normal pregnancies between the 16th and 20th week of gestation. Total hydroxyproline and creatinine levels, and their ratios, were not statistically different considering either the values at each week or those of the whole 5-week period. Our results, compared with the few others reported in the literature, can provide indications useful for defining the normal range in amniotic fluid, in relation to the weeks of gestation.