J Creighton | PubMed Health

PubMed1990

Ontogeny of light-induced decrease of N-acetyltransferase activity in explanted chick pineal glands.

The ontogeny of chick pineal serotonin N-acetyltransferase (NAT) activity was investigated in explanted chick pineal glands at 4, 10 and 21 d of age. Nocturnal levels of the enzyme and the response of the enzyme to light exposure were determined in pineal glands maintained in short-term culture at each age. The results indicate that nocturnal NAT activity was increased in the glands from older birds. Nocturnal levels of NAT activity at the time of the initiation of the experiment were threefold greater in glands from 21-d-old birds as compared to that in glands from 4-day-old chicks. The response to light was similar in all three ages examined; light induced a significant decrease in NAT activity within 60 min in explanted glands from 4-d-old chicks and within 180 min in the glands from the 10- and 21-d-old chicks. A paradoxical transient increase in enzyme activity occurred immediately (within 5 min) following light exposure which was significant in the glands from the youngest chicks, and present, but more variable, in the older chicks. These data indicate that the nocturnal enzyme activity is greater in glands from older birds, but that light exposure of explanted glands initiates a transient rise followed by a decrease in NAT activity at all three ages.

Acetyltransferases↗

PubMedDate not supplied

Surgical correction of spastic equinovarus deformity in the adult head trauma patient.

The results of 59 surgical procedures for correction of spastic equinovarus deformity of the foot using the split anterior tibial tendon (SPLATT) were reviewed in 54 adults with traumatic head injury. The mean time of follow-up was 49.7 months. Thirty-nine individuals had hemiplegic involvement, three had triplegic involvement, and 12 were quadriplegic. Evaluation of the patterns of lower extremity muscle activity preoperatively by dynamic electromyography in 33 patients showed no significant difference from that seen in the hemiplegic stroke population, namely, spastic calf muscles with overactive toe flexors and anterior tibial muscle. At follow-up all feet were in a plantigrade position. The only complication was a superficial skin slough on the dorsum of the foot which healed uneventfully. Postoperatively, 18 extremities (31%) were brace-free. Forty-one extremities required support because of calf weakness, ataxia, or proprioceptive deficits. Of the 15 patients who were nonambulatory prior to surgery, nine (60%) became ambulatory. At follow-up 36 patients (67%) were independent ambulators, four (7%) required supervision assistance, two (4%) required standby assistance, and six (11%) required minimal assistance. The six individuals (11%) who remained maximally assisted or nonambulatory had improved wheelchair positioning and shoe wear. These results show that the split anterior tibial tendon transfer is a safe and effective procedure for the head trauma patient since it corrects the equinovarus deformity, allowing for improved shoe wear and wheelchair positioning in the nonambulatory individual and improved ambulation with decreased brace wear in the more functional patient.

Adolescent↗