Hospital resource utilization by American Indians/Alaska Natives for alcoholism and alcohol abuse.

Previous work examining the issue of alcoholism and alcohol abuse among American Indians and Alaska Natives can be broadly categorized as either descriptions of the consumption patterns and behaviors of specific tribes or mortality studies, focusing on deaths due to alcoholism, alcohol abuse, chronic liver disease, or cirrhosis. A major shortcoming of previous studies has been that they have not looked at the burden this problem has imposed upon the system of health care delivery for this minority population. By using an International Classification of Diseases, Ninth Revision, Clinical Modification taxonomy of diagnostic codes developed by the National Institute on Alcoholism and Alcohol Abuse (NIAAA) and the national Indian Health Service (IHS) inpatient database for direct and contract admissions, utilization patterns for 43 IHS facilities were investigated. The period of study was 1980-1988, and our case definition included any individual 14 years and older who had any mention upon discharge of an alcohol-related diagnosis (ARD). For the 9-year period under investigation, 43,302 adult inpatient admissions occurred at the 43 IHS facilities for ARD. These admissions accounted for an overall estimated per annum rate of 13.7% of the adult inpatient days. In addition, age and gender specific discharge rates for ARD were estimated and compared to reported ARD discharge rates of the United States civilian population prepared by the NIAAA using the National Hospital Discharge Survey over the period 1979-1988. In contrast, the IHS discharge rates for ARD were three times greater than reported ARD discharge rates for the United States civilian population.

Effects of sampling location on data sensitivity in a three compartment model.

A computer simulation of a three compartment model was developed to examine the effect of sampling location on the accuracy of estimates of system parameters. Results indicate that the best estimates are obtained when all three compartments are sampled. Sampling from only one compartment tends to result in the poorest estimates.

Acid mine drainage from inactive eastern coal operations.

The most widely used technique for abatement of acid drainage from inactive surface mines and refuse disposal areas is revegetation of a soil cover applied to the waste material. Nonetheless, acid production often persists and in some cases, limits establishment of vegetation. This paper reports on several field studies intended to determine the location of pyrite oxidation zones and migration pathways of oxidation products at inactive spoil and refuse sites.Oxygen required for pyrite oxidation is believed to he provided in the gaseous state from the atmosphere. Therefore, the oxygen concentration in unsaturated mine waste should provide an estimate of the weathering tendency in the local environment. We are currently monitoring gas composition in refuse and spoil at six sites. Barren refuse appeared to be oxygenated (>2% 02) in a shallow zone extending less than 1 metre below the surface during most of the year. Preliminary data from coal spoil showed that oxygen can be available throughout the unsaturated thickness, even at a revegetated site. Gas composition varied vertically and laterally at a single site and also appeared to show seasonal dependence.Hydrologic factors are also important in acid production and transport. Discharge monitoring alone does not adequately describe the mass transport of acid products through the spoil. For example, at one reclaimed mine the mean sulfate content in six monitoring wells ranged from 24% to 240% of the mean concentration at the discharge point. Sources of recharge and relative flow rates determine the contribution of a particular zone to overall discharge quality.These basic studies of acid production and transport indicate some shortcomings of standard reclamation practices at certain sites. This information will he used to develop alternative abatement technology designed to mitigate acid production at the source.

Ferrous Iron Oxidation by Thiobacillus ferrooxidans: Inhibition with Benzoic Acid, Sorbic Acid, and Sodium Lauryl Sulfate.

Benzoic acid, sorbic acid, and sodium lauryl sulfate at low concentrations (5 to 10 mg/liter) each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of Thiobacillus ferrooxidans. The rate of chemical oxidation of ferrous iron in low-pH, sterile batch reactors was not substantially affected at the tested concentrations (5 to 50 mg/liter) of any of the compounds.

The pentaammineruthenium(III)-histidine complex in ribonuclease A as an optical probe of conformational change.

The formation of stable transition metal complexes between pentaammineruthenium(III) and the imidazole moiety of histidine residues in ribonuclease A is described. Studies of the kinetics of incorporation suggest that three of the four histidines are reactive and ion-exchange chromatography affords the isolation of three derivatives containing a single ruthenium-histidine complex. Equilibrium studies of the thermal- and urea-induced unfolding of one of these derivatives show that the ligand-to-metal change-transfer absorptions above 300 nm can be used to follow the conformational changes in the vicinity of the complex. For the urea-induced unfolding of this derivative, the coincidence of the transition curves obtained from the change-transfer absorptions and from difference ultraviolet spectroscopy at 286 nm, which measures the exposure of buried tyrosine residues to solvent, suggest that only two conformations, native and unfolded, are present at equilibrium in significant concentrations.

A combined post, core, and endodontic endosseous implant. Case report.

A hyperextended chrome-cobalt post and core also used as an endodontic endosseous implant served to stabilize a short mobile root and to provide for placement of a porcelain veneer metal crown. The technique is not complicated and does not require instruments other than those for routine endodontic treatment and for the construction of the post and core.