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Biomedical subjects

H J Adams

Publications and source records attributed to H J Adams.

36 records · Page 2Linked to original sources
PubMed1977

Spinal anesthesia with bupivacaine and tetracaine in sheep.

Spinal anesthesia was performed in sheep in order to compare hyperbaric solutions of 0.375 and 0.75% bupivacaine and tetracaine. There was no significant difference between the two compounds in the duration of sensory analgesia in the anal regions nor, at 0.75% in the time required for complete regression of the block. However, at 0.375% the duration of sensory analgesia and motor block in the hind limbs and the time required for complete regression were shorter with bupivacaine. In addition to exhibiting a higher incidence and a longer duration of motor block in the hind limbs, the sheep that received tetracaine were unable to stand on the hind limbs even after complete regression of block had occurred. Although further studies are required to establish the cause of this phenomenon, we suggest this may reflect a block of proprioceptor fibers.

Anesthesia, Spinal↗
PubMed1976

Local anesthetics. 2-Diethylamino-2',6'-acylxylidides.

A series of C-alkylated derivatives of lidocaine has been synthesized, and the local anesthetic potencies were determined. Activity reached a miximum with the butyroxylidide (alpha-ethyl group), but toxicity increased regularly with the number of carboons in the side chain. Spectral data showed the compounds to exist as associated H-bonded structures, the free base most likely as intramolecularly bonded trans amides and the hydrochlorides most likely as associated cis amindes.

Anesthetics, Local↗
PubMed1976

The local anesthetic activity of saxitoxin alone and with vasoconstrictor and local anesthetic agents.

STX (saxitoxin), alone and with various vasoconstrictor and local anesthetic agents, was evaluated for its ability to produce topical anesthesia on the rabbit cornea, peripheral nerve block in the rat, and epidural anesthesia in the dog. High frequency and long duration of block can be attained if sufficiently high concentrations of STX are used, although latency is long and the doses used may produce systemic toxicity. Frequency of satisfactory blocks and mean duration of block can be increased and systemic toxicity reduced if STX is administered with a vasoconstrictor agent. Conventional local anesthetic agents also enhance the nerve blocking activity of STX. When appropriate concentrations of STX, vasoconstrictor and local anesthetic agents are used, systemic toxic effects are not manifested and the blocks produced exhibit the rapid onset and high frequency of block characteristic of the local anesthetic agent and the remarkably long duration of STX.

Anesthesia, Epidural↗
PubMedDate not supplied

The local anesthetic activity of tetrodotoxin alone and in combination with vasoconstrictors and local anesthetics.

Tetrodotoxin (TTX), alone and in combination with various vasoconstrictors and local anesthetics, was evaluated for its ability to produce peripheral nerve blocks in the rat and central neural blocks in the cat and dog. High frequency and long duration of block can be attained if sufficiently high concentrations of TTX are used, although latency is long and high dosage may produce systemic toxicity. Frequency and mean duration of block can be increased and systemic toxicity reduced if TTX is administered with a vasoconstrictive agent. Conventional local anesthetics also enhance the nerve-blocking activity of TTX. When appropriate concentrations of TTX and local anesthetics are used, a high frequency of blocks characterized by short latency and long duration can be demonstrated. The studies present some indirect evidence that local anesthetics enhance TTX activity by reversibly increasing the permeability of various neural barriers to TTX.

Anesthesia, Epidural↗
PubMedDate not supplied

A multicenter evaluation of intramuscular ritodrine hydrochloride as initial parenteral therapy for preterm labor management.

Ninety-four patients in documented preterm labor received three intramuscular injections of ritodrine hydrochloride over an interval of 6 hours. They subsequently received the tocolytic agent intravenously for a minimum of 6 hours. The effects of ritodrine on uterine activity and the cardiovascular system were determined. Intramuscular ritodrine hydrochloride elicited a prompt and sustained reduction in the frequency of uterine contractions. The transition to intravenous treatment was achieved without an increase in uterine activity. Seventy percent of the patients had a sustained interval of uterine quiescence, and 96% had at least a 24-hour delay in delivery. Initial parenteral therapy with intramuscular ritodrine hydrochloride is safe and effective and may provide an alternative to intravenous therapy and a means of managing preterm labor during interhospital transport of a patient.

Adult↗