Rats show only a weak preference for the artificial sweetener aspartame

The preference of adult female rats for aspartame (L-asparty L-phenylalamine methyl ester) was measured using 24 hr/day and 30 min/day two bottle preference tests. At aspartame concentrations that humans find sweet (0.0125% to 0.05%) the rats failed to prefer aspartame to water. At higher concentrations (0.1% to 1.0%) half (n = 11) of the rats tested displayed mild (64%) to moderate (83%) aspartame preferences. The other half of the rats were indifferent or avoided the aspartame. Even at the most preferred concentration (1.0%) the rats' aspartame preference was much less than their preference for saccharin or sucrose, and they showed little increase in total fluid intake when given the aspartame solution. The results indicate that aspartame is not very palatable to rats, and suggest that it has little or no sweet, i.e., sucrose-like, taste to rats as it does to humans.     

Electron microscopy of the canine corneal basement membranes

The purpose of this study was to characterize the surface topographical features of the epithelial and endothelial (Descemet's) basement membranes of the canine cornea. Corneas were obtained from young, healthy dogs (<2 years old) with no history or evidence of previous ocular disease. The epithelium and endothelium was carefully removed preserving the anterior and posterior basement membranes. The specimens were examined by transmission electron microscopy and scanning electron microscopy. The epithelial and endothelial basement membrane surface topography is an intricate meshwork of pores and fibers measuring in the nanometer size range. The features of the endothelial basement membrane overall are smaller in size than the epithelial basement membrane. These surface topographical features may incite changes in epithelial and endothelial cell behavior.     

Differential regulation of IL-13 and IL-4 production by human CD8+ and CD4+ Th0, Th1 and Th2 T cell clones and EBV-transformed B cells

In the present study, the requirements and characteristics forthe production of IL-13 by human T cells, T cell clones andB cells were determined and compared with those of IL-4. IL-13was produced by human CD4⁺ and CD8⁺ T lymphocyte subsets isolatedfrom peripheral blood mononuclear cells and by CD4⁺ and CD8⁺T cell clones. CD4⁺ T cell clones belonging to T_h0, T_h1-likeand T_h2-like subsets produced IL-13 following antigen-specificor polyclonal activation. In addition, EBV-transformed B celllines expressed IL-13 mRNA and produced small amounts of IL-13protein. Expression of IL-13 mRNA and production of IL-13 proteinby peripheral blood T cells and T cell clones was induced rapidlyand was relatively long lasting, whereas IL-4 production bythese cells was transient In addition, IL-13 mRNA expressionwas induced by modes of activation that failed to induce IL-4mRNA expression. IL-13 shares many biological activities withIL-4 which Is compatible with the notion that the IL-13 andIL-4 receptors share a common component required for signaltransduction. However, IL-13 lacks the T cell-activating propertiesof IL-4. Here we have shown that this is related to the factthat T cells fall to bind radiolabeled IL-13 and do not expressthe IL-13-speclflc receptor component Taken together, theseresults indicate that the differences In expression and biologicalactivities of IL-4 and IL-13 on T cells may have consequencesfor the relative roles of these cytokines In the immune response.     

Dysfibrinogenemia associated with hepatoma. Increased carbohydrate content of the fibrinogen molecule.

Abnormal coagulation studies indicative of a dysfibrinogen were found in the plasma of four of seven patients with malignant hepatoma. The abnormal fibrinogen was characterized by prolonged prothrombin, thrombin and reptilase times and inhibition of the coagulation of normal plasma. Purified fibrinogen revealed abnormalities similar to those in plasma. The functional defect was one of delayed polymerization of the fibrin monomer. The carbohydrate content of the abnormal fibrinogen was increased, and this change was related to the abnormal fibrinogen function. Enzymatic cleavage of sialic acid from the abnormal fibrinogen restored fibrinogen function to normal. This hepatoma-associated dysfibrinogen (acquired dysfibrinogenemia) is similar in many respects to fetal fibrinogen and may represent the presence of a fetal form of fibrinogen in hepatoma.     

A Prospective Follow-Up Study of Cognitive Functions After Electroconvulsive Therapy

The authors studied primarily nonmemory cognitive functioning in a sample of 13 melancholic patients tested prior to electroconvulsive therapy (ECT) and at various intervals during a 1-2 year post-ECT follow-up period. Compared with 13 age-matched normal controls, the patients performed significantly worse at baseline and immediately after the sixth ECT, but were not significantly different at the 30-day, 6-month, and 1-2 year assessments. At 1-2 years post-ECT, cognitive impairment among patients was substantially and significantly less than observed pre-ECT.     

A Hypothesis to Explain Divergent Findings Among Studies Comparing the Efficacy of Unilateral and Bilateral ECT in Depression

This article explains divergent reports on the relative efficacy of unilateral and bilateral electroconvulsive therapy (ECT) by hypothesizing a therapeutic effect of both seizure and electrical stimulus, with the seizure's effect based on its intensity and generalization. The effect of the stimulus is normally obscured by the seizure but emerges with reduced electrical dosage or elevated threshold. These circumstances favor a therapeutic advantage for bilateral ECT, which introduces more electrical charge into a larger and differently distributed volume of brain and induces greater seizure generalization, more diencephalic stimulation, and a relative decrease in left relative to right hemisphere electroencephalographic (EEG) frequencies.