Event-related potentials to match and mismatch letters in an immediate item recognition task.

During an immediate item recognition task, ERP differences to match and mismatch letters occurred in the N1 component, as well as the P3 component, of the stimulus related wave form. The pattern of ERP differences was similar to that reported previously for words in a delayed list recognition task, (Warren, 1980). The ERP differences to match and mismatch letters appeared unaffected by visual field of presentation (left, center, right) or hemisphere of recording site (P3, P4).

Urine excretion of 5-S-cysteinyldopa and serum sialic acid as tumor markers in human melanomas.

This study examines 5-S-cysteinyldopa, which is a melanoma-associated marker, and sialic acid whose increase appears to be a common feature of numerous cancers. In spite of some interferences due to sun exposure, 5-S-cysteinyldopa seems a significant indicator of metastases; the difference between 46 metastasis-negative and 34 metastasis-positive melanomas is significant at P less than 0.001.

Variation of the carbohydrates of glycoproteins of cells growing on different surfaces.

The carbohydrate components of some glycoproteins of hamster cells differ as a function of their growth on various substrates; glass, plastic, or plastic coated with collagen. This observation is interpreted as an effect of the environment on cellular structure at the molecular level. The basis of the change and its possible significance are discussed.

A pathway for the interconversion of hexose and pentose in the parasitic amoeba Entamoeba histolytica.

Isotope studies indicate that hexose-to-pentose interconversion by axenic Entamoeba histolytica conserves the C-1 and C-6 hexose carbon atoms. Transketolase was readily identified in amoebal extracts, and transaldolase could not be demonstrated. However, sedoheptulose 7-phosphate is a substrate for the PPi-dependent amoebal phosphofructokinase, and sedoheptulose 1,7-bisphosphate is cleaved by amoebal aldolase to dihydroxyacetone phosphate and erythrose phosphate.

Decreased synthesis of high-molecular-weight glycopeptides in human promyelocytic leukemic cells (HL-60) during phorbol ester-induced macrophage differentiation.

The human promyelocytic leukemia ell line, HL-60, synthesized a class of high-molecular-weight (M.W. 5000 to 7000), N-linked glycopeptides as the major class of protein-bound carbohydrates.

A model for evaluation of postural hypotension induced by drugs in conscious restrained normotensive rats.

A rat model was developed for use in evaluating postural hypotensive activity of a compound. Conscious normotensive rats were restrained on a tilt board with special restrainers to avoid blocking limb circulation. Dose response curves were explored to delineate the potential postural hypotensive activity of a compound.

Aortic smooth muscle cells contain vimentin instead of desmin.

The 10-nm filament subunit proteins of smooth muscle cells in the mammalian aorta were analyzed by immunofluorescence and by two-dimensional gel electrophoresis. Indirect immunofluorescence studies on frozen sections of aorta showed intense staining of the tunica media by antibodies to vimentin, whereas no reaction could be detected with antibodies to desmin. Crude preparations from the tunica media contain a protein with molecular weight and isoelectric point similar to those of vimentin.

Alpha asymmetry as a function of cognitive mode: the role of lateral eye movements.

When monitored concurrently, the spontaneous lateral eye movements and alpha asymmetry associated with mental activity were themselves interrelated. Left eye movements were associated with a decrease in the ratio of right to left hemisphere alpha, while right eye movements resulted in an increase in this ratio, independent of cognitive task. The results were interpreted as evidence for a direct effect of oculomotor activity on alpha asymmetry.

The importance of catecholamine uptake inhibition in the reversal of guanethidine blockade of adrenergic neurons.

Adrenergic neuron blockade was induced by guanethidine in the pithed rat preparation. The pressor response to spinal electric stimulation was inhibited. The guanethidine blockade was reversed or prevented not only by tricyclic antidepressants but also by tripelennamine (an H1 antihistamine), tranylcypromine (a monoamine oxidase inhibitor) and viloxazine (a new antidepressant structurally unrelated to tricyclic antidepressants).

The membrane glycoproteins of the malignant cell.

Experiments are described and reviewed demonstrating that the bound carbohydrates of glycoproteins of many forms of malignant cells differ from their normal counterpart. The difference involves many oligosaccharide groups and is essentially quantitative. The characteristics of the difference are discussed.

Incorporation of glucose carbon into ribonucleotides of axenic Entamoeba histolytica.

Axenic Entamoeba histolytica grown with (UL-14C)glucose in TP-S-1 medium were capable of biosynthesizing ribose from labeled glucose. RNA isolated by phenol extraction was hydrolyzed to the ribonucleotide level by alkaline hydrolysis. The hydrolysate, chromatographed on ion exchange resins, yielded AMP, GMP, and UMP, but not CMP containing labeled glucose carbon.

Glycosaminoglycans and other carbohydrate groups bound to proteins of control and transformed cells.

The membrane glycoproteins from control (BHK21/C13) and Rous sarcoma virus-transformed (C13/B4) baby hamster kidney cells labeled with D-[14C]- or D-[3H]glucosamine, respectively, were purified by means of polyacrylamide electrophoresis and gel electrofocusing. The homogeneity of the isolated glycoproteins was demonstrated by analysis of the NH2-terminal peptides. Some purified glycoproteins were found to be hybrid molecules in terms of the type of oligosaccharides they bear.

Comparison of glycopeptides from control and virus-transformed baby hamster kidney fibroblasts.

Glucosamine-labeled glycopeptides from control and virus-transformed BHK fibroblasts were characterized by size, lectin affinity, charge, and composition. As already demonstrated, on the basis of elution position on a column of Sephadex G-50, transformed cells contained a greater proportion of large glycopeptides than did control cells. Transformed cells also contained a larger proportion of glycopeptides which do not bind to Con A-Sepharose.

The detection of smooth muscle desmin-like protein in BHK21/C13 fibroblasts.

Three distinct proteins, actin (42,000 daltons), the principal form of fibroblast 10 nm filament protein (55,000 daltons), and a protein with a molecular weight of 52,000 and a pI of 5.8 were detected in nonionic detergent-insoluble cytoskeletal and 10 nm filament preparations of control BHK21/C13 and line 9 hamster fibroblasts. Cytoskeletal preparations of other hamster fibroblast cell types, such as NIL8 and primary embryo fibroblasts, contained the 55,000-dalton component but lacked the 52,000-dalton protein.