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Biomedical subjects

N Smith

Publications and source records attributed to N Smith.

At least 253 records · Page 14Linked to original sources
PubMed1975

Ion effects on protein-nucleic acid interactions: the disassembly of the 50-S ribosomal subunit from the halophilic bacterium, Halobacterium cutirubrum.

The 50-S ribosomal subunits from the extreme halophilic bacterium, Halo-bacterium cutirubrum, stable structurally and functionally in concentrated salt solutions were subjected to ionic environments depleted in either K+ or Mg2+ or both. Under these conditions specific classes of proteins are released from the subunit along with the 5 S RNA. Two-dimensional electrophoretic analysis of the resultant split protein fractions indicate some mutually exclusive effects of specific ions on the binding of specific proteins to the 23 S RNA as well as on the retention of 5 S RNA within the ribosomal macrostructure.

Bacterial Proteins↗
PubMed1975

Extraction socket healing in the calcium deficient rat.

The healing of extraction sockets was studied in normal and calcium deficient rats. New bone formation occurred earlier and proceeded more rapidly in the deficient rats, and the newly formed trabeculae were sparse and delicate but with a similar osteoporotic appearance to the alveolar bone.

Animals↗
PubMed1975

Acquistion and extinction of a conditioned hyperthermic response to a tone paired with morphine administration.

Following a 7-day baseline period, five male hooded rats were injected daily with a constant dose (20 mg/kg) of morphine sulfate. Immediately following the injections they were taken to a sound-attenuated room and exposed to a 5,000 cps tone for 90 min. On certain predetermined days of the morphine treatment, rectal temperatures were measured before each injection and 30 min following the onset of the tone. Also, after the 11th, 19th, and 57th morphine-tone pairing, the rectal temperatures were measured before and after a saline injection which was paired with tone. On these days tone presentations by themselves were sufficient to cause a reliable increase in rectal temperature resembling that seen following an injection of morphine. When tone presentations were continued, without further pairing with morphine, the hyperthermic response to the tone was gradually extinguished. However, a significant increase in rectal temperature in response to the tone was again observed following a second set of five morphine-tone pairings.

Animals↗
PubMed1975

Reduction of morphine-withdrawal body shakes by a conditional stimulus in the rat.

Narcotic dependence in rats was established, in five days, by administering intravenous injections of morphine sulfate in increasing doses. From day six onward, dependence was maintained by administering a morphine injection (15 mg/kg) every 6 h throughout the day, and each of these injections was paired with a tone. After 16 morphine-tone pairings, test trials, in which the tone was presented in the absence of morphine, were instituted. These tone presentations significantly reduced morphine-withdrawal "wet shakes" in rats which received morphine-tone pairings, but not in rats which received control treatments.

Acoustic Stimulation↗