Sensitivity of different human cell lines in the biologic evaluation of dental resin-based restorative materials

Abstract— Three different cell lines of human origin, i.c. human epithelica cells (NCTC 2544), and epithelial and fibroblast like cells from human gingiva, were tested for their sensitivity fo three different dental resin-based restorative materials using four different assay techniques. The techniques applied were cell growth measurements by cell number, ⁵³Cr-release, Agar overlay with neutral red staining and colony formation. The ranking of teh cells according to their sensitivity ot the materials varied with the assay technique applied, with no cell line being consistently more sensitive than the others. It is also suggested that the type of medium applied could be important for the result obtained.     

Backward masking and skin conductance responses after conditioning to nonfeared but fear-relevant stimuli in fearful subjects

The present study examined two issues. Are skin conductance responses conditioned to fear-relevant stimuli, as contrasted with responses conditioned to fear-irrelevant stimuli, elicited after merely an automatic, nonconscious analysis of the stimulus content? Do fearful subjects show better conditioning to nonfeared but fear-relevant stimuli (e.g., conditioning to spiders in snake-fearing subjects) than do nonfearful subjects? Subjects afraid of snakes, but not of spiders, or vice versa (n= 32) and nonfearful subjects (n= 32) were shown either fear-relevant stimuli (snakes or spiders and rats) or fear-irrelevant stimuli (flowers and mushrooms) in a differential conditioning paradigm, where one of the stimuli was followed by an electric shock. During a subsequent extinction phase, the conditioned stimuli were presented under backward masking conditions, preventing their conscious recognition. Consistent with our hypothesis, during the masked extinction of the conditioned stimuli, differential skin conductance responses to conditioning and control stimuli remained only for subjects conditioned to fear-relevant stimuli. Both fearful and nonfearful control subjects had significantly larger differential electrodermal responses to fear-relevant than to fear-irrelevant stimuli. However, contrary to our hypothesis, fearful subjects did not show enhanced conditionability to their nonfeared but fear-relevant stimuli as compared with nonfearful control subjects.     

Nonsecretory Myelomatosis without Intracellular Immunoglobulin

A patient with multiple myeloma is reported with severe hypogammaglobulinaemia but without monoclonal immunoglobulin (M-component) in the serum or Bence Jones protein in the urine. In May-Grünwald-Giemsa stained bone marrow film 45 % of the cells resembled plasma cells. Marrow immunofluorescent studies showed no increase of immunoglobulin containing cells. Ultrastructural studies showed a large number of cells with a well developed rough endoplasmic reticulum and other morphological features characteristic for plasma cells.     

Organized Activation During Atrial Fibrillation in Man

Atrial Fibrillation Organization. Introduction: Atrial fibrillation is not entirely random, but little is known about the spatiotemporal endocardial organization and its surface ECG manifestations. Methods and Results: In 16 patients with atrial fibrillation (chronic, n = 14), endocardial mapping of the trabeculated, the posteroseptal smooth right atrium, and the coronary sinus was performed using multipolar catheters. The surface ECG was analyzed by determining “fibrillation wave” (F wave) amplitude, rate, and polarity. During 50 minutes of atrial fibrillation, an organized activation was present 72%± 32% of the analyzed time on the trabeculated, 19%± 15% on the smooth right atrium (P < 0.01), and 51%± 33% along the coronary sinus (P < 0.05). The direction of organized activation was craniocaudal in 72%± 16%. caudocranial in 10%± 9% (P < 0.01), and indeterminable in 18%± 11%. The mean surface F wave amplitude in lead V₁ was 0.128 ± 0.06 mV during 28 seconds of atrial fibrillation with a craniocaudal direction of activation and 0.065 ± 0.02 mV during a disorganized activation (P < 0.01). A stable relation between surface F waves and organized trabeculated right atrial activation was observed, and the mean F wave cycle length (190 ± 27 msec) was highly comparable to the simultaneously measured endocardial cycle length (191 ± 27 msec, correlation coefficient 0.97). F wave polarity in V₁ was positive in 12 of 14 patients during craniocaudal and negative in 11 of 14 patients during caudocranial rigbt atrial free-wall activation. Conclusion: An organized activation during atrial fibrillation with a predominant craniocaudal direction on the trabeculated right atrium is frequently present and influences the appearance of “coarse” or “fine” atrial fibrillation as well as F wave polarity on the surface ECG.