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Biomedical subjects

D Chandler

Publications and source records attributed to D Chandler.

105 records · Page 6Linked to original sources

Effects of local anesthesia on gingival cAMP levels.

The basal levels of cAMP in the attached gingiva of Rhesus monkeys and the changes in tissue cAMP levels produced by infiltration anesthesia with lidocaine and lidocaine containing 1:100,000 epinephrine were studied. The basal level of cAMP in uninjected monkey gingiva ranged from 12 to 20 picomoles of cAMP per mg of gingival protein. This level was 75 times greater than the cAMP content of monkey blood plasma. Infiltration of the attached gingiva with saline or plain lidocaine for 5 minutes did not produce any significant changes in tissue cAMP levels. Infiltration of the gingiva with lidocaine containing 1:100,000 epinephrine, on the other hand, caused a very marked increase in tissue cAMP levels. Thirty seconds after infiltration with lidocaine with 1:100,000 epinephrine there was a 250% increase in cAMP content of the anesthetized tissue versus the uninjected control tissues. The maximal increase in tissue cAMP levels was observed 5 minutes after infiltration when the cAMP content of the gingiva was 1000 to 1100% above the control level. It is proposed that regulation of tissue cAMP levels by epinephrine or other agents may prove of therapeutic usefulness in regulating inflammation and healing of tissues after surgery or other trauma.

Anesthesia, Dental↗

The weights of aboriginal infants: a comparison over 20 years.

At Cherbourg Aboriginal Settlement the weight gains of infants remained at a constant level below the Australian average from 1953 to 1972. During this period the infant death rate decreased from about 28 per 1,000 live births to about 40 per 1,000 live births. At Palm Island Settlement the death rates have remained high and the growth rates low. The pattern at Cherbourg suggests that the people at Cherbourg have learnt how to use appropriately the hospital and health services, but have not yet made any major changes in the standards of infant care.

Age Factors↗

Deafness after bacterial meningitis.

Seventeen children with previous bacterial meningitis and 17 sib controls were examined clinically and otoscopically. They were also tested with air-conduction and bone-conduction audiometry and evaluated by tympanometry. There were no major neurological abnormalities and few otoscopical signs of ear disease. 21% of the ears showed abnormalities on air-conduction audiometry but all were normal on bone-conduction audiometry. 30% had abnormal middle-ear pressures (more negative than 100 mm water) on tympanometry and 7% had abnormal compliance of the drum. There were no significant differences on any test between the postmeningitis children and the sib controls. Population studies have confirmed that minor hearing loss due to middle-ear dysfunction is common in children, but is probably temporary in most of them. We have found no excess of middle-ear dysfunction and no sensorineural deafness in these postmeningitis children, but other workers have shown that nerve deafness may occur in association with clinical neurological damage. However, much of the deafness attributed to bacterial meningitis in other studies may well reflect population variability.

Child↗

Infant death rates in Queensland, 1962 to 1972.

Published statistical material has been used to analyse the infant death rate in Queensland. The neonatal death rates, which tend to reflect the level of obstetric care, were approximately twice as high in the Peninsula Division as in Brisbane, and the late infant mortality rate was almost eight times as high in the Peninsula Division as in Brisbane. In the Peninsula there has been no fall in infant death rate over the 11 years studied. One small area had an infant mortality rate of 100 deaths per 1,000 live births. The areas with the highest infant death rates were those with a significant Aboriginal population. The data show that proximity to major health facilities does not ensure low infant death rates and in the Brisbane Metropolitan Division there were threefold differences in late infant death rates. It seems likely that infant death rates are influenced by the economic status and education of parents and by the priority they place on infant care. The study has shown that published statistical data can detect areas within Queensland with high infant death rates, and could therfore be used to direct resources to improve the well-being of infants in these areas.

Australia↗

Ca++ and pancreatic amylase release.

The effects of Ca'++ on release of amylase by mouse pancreas in vitri was studied. The cholinergic agonist bethanechol was depressed about 50% in O Ca'++ medium. When pancreatic fragments were superfused with O Ca'++ medium, bethanechol still produced a normal stimulation of amylase release after half of the total tissue Ca'++ was washed out. This Ca'++ loss included both extracellular and some intracellularCa'++. Uptake and equilibration of '45Ca'++ into pancreatic fragments was multiphasic, with total equilibration with stable Ca'++ still not reached after 3 h. Addition of bethanechol had no effect on the rate of '45Ca uptake and equilibration. '45Ca'++ efflux was not influenced by superfision in O Ca'++ medium, while thestimulation of '45Ca'++ efflux by bethanechol was enhanced. It is concluded that extracellular Ca'++ and/or Ca'++ influx is not of major importance in triggering pancreatic enzyme release, but that extracellular Ca'++ may regulate the release process thus accounting for the parallel changes in unstimulated and stimulated amylase release.

Amylases↗

Regulation of a hevein-like gene in Arabidopsis.

An Arabidopisis cDNA clone was isolated that encodes a protein similar to the antifungal chitin-binding protein hevein from rubber tree latex. This hevein-like (HEL) mRNA was inducible by either turnip crinkle virus infection or ethylene treatment. In addition, expression was moderately inducible by treatment with the resistance-inducing compounds salicylic acid and 2,6-dichlorisonicotinic acid. The 786-bp cDNA contains an open reading frame of 212 codons. The deduced amino acid sequence contains a putative signal sequence of 21 amino acids followed by a 43-amino-acid cysteine-rich lectin domain and a 129-amino-acid carboxy-terminal domain. The predicted protein is approximately 70% identical to hevein, to the wound-inducible WIN1 and WIN2 proteins from potato, and to PR-4, a pathogenesis-related protein from tobacco.

Amino Acid Sequence↗