Biomedical subjects

J A Lugo

Publications and source records attributed to J A Lugo.

2 recordsLinked to original sources

PubMed1992

Nigericin forms highly stable complexes with lithium and cesium.

Nigericin is a monocarboxylic polyether molecule described as a mobile K+ ionophore unable to transport Li+ and Cs+ across natural or artificial membranes. This paper shows that the ion carrier molecule forms complexes of equivalent energy demands with Li+, Cs+, Na+, Rb+, and K+. This is in accordance with the similar values of the complex stability constants obtained from nigericin with the five alkali metal cations assayed. On the other hand, nigericin-alkali metal cation binding isotherms show faster rates for Li+ and Cs+ than for Na+, K+, and Rb+, in conditions where the carboxylic proton does not dissociate. Furthermore, proton NMR spectra of nigericin-Li+ and nigericin-Cs+ complexes show wide broadenings, suggesting strong cation interaction with the ionophore; in contrast, the complexes with Na+, K+, and Rb+ show only clear-cut chemical shifts. These latter results support the view that nigericin forms highly stable complexes with Li+ and Cs+ and contribute to the explanation for the inability of this ionophore to transport the former cations in conditions where it catalyzes a fast transport of K+ greater than Rb+ greater than Na+.

Biological Transport↗

PubMedDate not supplied

An epidemiologic study of the human bite.

The 892 human bites reported to the New York City Department of Health in 1977 were analyzed by time, place, and the victim's characteristics. The bites appeared to have a seasonality, increasing in March and exceeding the mean monthly average through August. The bite rate for the entire city, 10.7 per 100,000 population, was exceeded in 5 of the 10 Brooklyn health districts; one of these districts reported a rate of 60.9 human bites per 100,000 population. Most of the bites with identifiable locations occurred indoors (63.2 percent). In 72.8 percent of the bite episodes in which the activities surrounding them were known, these activities were aggressive in nature. Males exceeded females as bite victims in all age groups except those 10-20 and 55-60 years. Bites of the upper extremity accounted for 61.2 percent of the total bites. Left-sided bites exceeded right-sided, except for the hand. In frequency of reported occurrence, the human bite ranks third, after the dog bite and the cat bite. Human bites may be a useful indicator of antisocial behavior.

Adolescent↗