Differential effects of lipids on the osmotic fragility of lysosomes

The effect of a wide range of concentrations of oleic acid, oleyl alcohol and oleic acid methyl ester on lysosomal stability has been studied under both hypotonic and isoosmotic medium conditions. Both oleic acid and oleyl alcohol exhibited a biphasic interaction pattern with lysosomes; stabilizing at low concentrations and labilizing at high concentrations. Lysosome labilization by the ester required an initial lag period.

Effect of hashish compounds on mouse peritoneal macrophages

Light microscopy reveals an induction of extensive vacuolation in the macrophage after exposure to either delta 1-tetrahydrocannabinol or cannabidiol. Numerous small vacuoles appear in the cell periphery as early as 15 minutes after exposure (at 37degrees C.) to either of the compounds in 20 per cent newborn calf serum-Dulbecco's modified Eagle medium. The small lucent vacuoles coaleasce and yield enormous vacuoles which dominate the the cytoplasm. At approximately 3 hours, many of the vacuoles seem to burst with a concomitant expulsion of cell interior. The effect of hashish compounds on macrophages is essentially irreversible; exposure for 15 minutes to 10(-5) m of delta 1-THC or cannabidiol and a thorough wash in 20 per cent serum-medium, suffices to trigger the sequence of vacuolation and total cell death in the culture. Two major processes involving early reorganization of cellular membranes have been observed using electron microscopy. One relates to the formation of numerous autophagic vacuoles full of organelles, the other relates to the appearance of cytoplasmic inclusions representing extensive destruction of intracellular constituents. Both types of cytoplasmic change have been observed in alveolar macrophages of hashish smokers. Thus, the conditions in the in vitro studies are similar to conditions in people exposed to hashish smoke.

Another dimension for assessment of speech-sound discrimination: latency of response

The relationship of speech-sound-discrimination skills and speed of responding was investigated by presenting monosyllabic nouns in three different listening conditions to a total of 72 nursery, kindergarten, and first-grad children divided into three equal-sized groups. Speed of responding was related to the age of subjects, accuracy of responding, and context of presentation of stimulus items. There was a consistent decrease in latency of responding as age increased. Error responses had greater response latencies than correct responses. Response latencies for different contexts of presentation of stimulus items were longest for the paired-comparison context and shortest for the carrier-phrase context. Speed of responding could be considered as an additional parameter when evaluating speech-sound-discrimination skills.

Variables influencing performance on speech-sound discrimination tests

Stimulus items were presented in three different contexts and under two different listening conditions to a total of 72 nursery, kindergarten, and first-grade children divided into equally sized groups on the basis of age. Results indicated that both the context of stimulus item presentation and the presence of background noise affected accuracy of performance. Children in all three groups consistently made more errors in the context using limited grammatical and phonetic cues. Noise disrupted performance in all contexts, but the greatest disruption occurred in the paired-comparison context. It appeared that contexts employing grammatical cues were more resistant to disruption from background noise. The results of this investigation also indicated that the performance of young children may have been affected by factors other than their ability to discriminate speech sounds.