Biomedical subjects

C R Smith

Publications and source records attributed to C R Smith.

At least 361 records · Page 20Linked to original sources

PubMed1975

Preparation and antitumor activity of a rearranged ester of cephalotaxine.

For further evaluation of structure-activity relationships among the Cephalotaxus alkaloids, a "rearranged" ester (2b) of cephalotaxine was prepared, one which is an isomer of deoxyharringtonine (5a). The parent alkaloid, cephalotaxine (1a), was allowed to react with thionyl chloride to replace its hydroxyl group with chlorine. The resulting chloro compound 1b, on treatment with the silver salt of half ester 6, yielded 2b via an allylic rearrangement followed by further double bond migration. The new "rearranged" deoxyharringtonine isomer 2b proved to be inactive in the P-388 lymphocytic leukemia system and thus further delineated the structural requirements for antitumor activity in this series of alkaloids.

Alkaloids↗

PubMed1975

Residual hearing and speech production in deaf children.

Residual hearing, phoneme recognition, speech production errors, and selected background variables were examined in 40 congenitally deaf children of normal intelligence who had no apparent anomalies other than deafness, in an effort to identify factors most closely associated with speech intelligibility. Mean intelligibility of the recorded speech of the children, to inexperienced listerners, was 18.7%, corresponding closely with results of previous studies. Scores on the total and some portions of the phoneme recognition test showed significant correlations with both phoneme production and speech intelligibility. The correlation between phoneme production errors and intelligibility was -0.80. A sizable proportion of the dispersion could be accounted for by certain prosodic errors, such as those resulting from improper phonatory control. Errors of place of articulation and voicing remained in essentially the same proportion for all speakers. Errors of manner and combined place and manner of articulation showed a slight systematic decrease from the poorest to the best speakers. Omissions decreased sharply, but not systematically. Vowel errors showed the most marked and systematic decrease as intelligibility improved. Children of deaf parents were poorer in phoneme recognition and in speech intelligibility than children with comparable residual hearing but with hearing parents.

Adolescent↗

PubMed1975

Differential effects of prenatal rhythmic stimulation on neonatal arousal states.

This study tested Salk's hypothesis that the human fetus is prenatally imprinted to the repetitive intermittent sound of the maternal heartbeat. 2 groups of neonates were selected prior to birth based on low (70-80 bpm) and high (100-110 bpm) maternal resting heart rates. At 24-48 hours old, the neonates were exposed to a 75-bpm, 105-bpm, or a no-sound tape, each prior to 1 of 3 different mealtimes. The prediction, based on Salk's hypothesis, that neonates would quiet most to their own mother's heart rate compared with the unfamiliar heart rate was not supported. Greater arousal reduction was found for any rhythmic sound compared with no sound. M-st important, clear prenatal influences on postnatal quieting behavior were demonstrated. Babies born to low-heart-rate mothers fell asleep faster, slept longer, and cried less under all conditions than did high-maternal-heart-rate children.

Acoustic Stimulation↗

PubMed1974