Glidewire treatment of resistant coronary occlusions.

Inability to cross the site of occlusion with a guidewire is the most common cause of failed angioplasty. The Glidewire, a kink-resistant, flexible wire with a hydrophilic coating, was applied to 71 (59 total, 12 subtotal) refractory occlusions, resulting in an overall angioplasty success rate of 45%. The Glidewire may improve the success rate for PTCA of total and subtotal occlusions that cannot be crossed with conventional guidewires.

The prevention of softball injuries: the experience at Yokota.

Softball injuries occur in a predictable pattern. Review of Emergency Room records at Yokota AB Hospital for three summers showed a high incidence of ankle injuries. Sliding is the cause of many of these injuries. Common sense interventions should reduce the incidence of softball injury. Use of low profile bases or the outlawing of sliding are reasonable interventions that should be considered by policy makers.

Thunderstorms: an important mechanism in the transport of air pollutants.

Acid deposition and photochemical smog are urban air pollution problems, and they remain localized as long as the sulfur, nitrogen, and hydrocarbon pollutants are confined to the lower troposphere (below about 1-kilometer altitude) where they are short-lived. If, however, the contaminants are rapidly transported to the upper troposphere, then their atmospheric residence times grow and their range of influence expands dramatically. Although this vertical transport ameliorates some of the effects of acid rain by diluting atmospheric acids, it exacerbates global tropospheric ozone production by redistributing the necessary nitrogen catalysts. Results of recent computer simulations suggest that thunderstorms are one means of rapid vertical transport. To test this hypothesis, several research aircraft near a midwestern thunderstrom measured carbon monoxide, hydrocarbons, ozone, and reactive nitrogen compounds. Their concentrations were much greater in the outflow region of the storm, up to 11 kilometers in altitude, than in surrounding air. Trace gas measurements can thus be used to track the motion of air in and around a cloud. Thunderstorms may transform local air pollution problems into regional or global atmospheric chemistry problems.

Captopril enhances aminoglycoside nephrotoxicity in potassium-depleted rats.

We demonstrated that potassium depletion significantly increased gentamicin nephrotoxicity in Sprague-Dawley rats (100 mg X kg-1 X day-1). To determine whether this enhanced toxicity was mediated by renin secretion, we evaluated the effect of a converting enzyme inhibitor in this model. When we administered the combination of captopril (100 mg X kg-1 X day-1) and gentamicin in potassium-depleted rats, we observed a surprising and significant adverse effect of this combination on the clearances of inulin (CIn) and PAH (CPAH) and renal blood flow (RBF). Pretreatment with indomethacin significantly improved CIn and CPAH, and potassium repletion abolished this effect entirely. In potassium-depleted animals that received both gentamicin and captopril, the intra-arterial administration of imidazole, a thromboxane synthetase inhibitor, significantly reduced urinary TXB2 excretion and significantly improved RBF and CIn in vivo. In the same group of animals, administration of the kallikrein antagonist aprotinin also significantly increased both RBF and CIn. To measure total renal thromboxane B2 production (TXB2), we perfused kidneys ex vivo with cell-free perfusate. Three groups of animals were studied: potassium-repleted control animals, potassium-depleted control animals, and potassium-depleted animals treated with gentamicin alone, captopril alone, or the combination of gentamicin and captopril. We measured TXB2 in renal venous effluent by radioimmunoassay. Ex vivo perfused kidneys from potassium-depleted control animals produced significantly more TXB2 than potassium-repleted controls. Kidneys from potassium-depleted animals that received both gentamicin and captopril produced significantly greater amounts of TXB2 than did kidneys from potassium-depleted animals treated with captopril alone, gentamicin alone, or control potassium-depleted kidneys. The administration of imidazole ex vivo at a rate equivalent to in vivo administration (10 microM/min) reduced TXB2 production by potassium-depleted kidneys that received the combination of gentamicin and captopril to that of potassium-repleted control kidneys. These results suggest that the deleterious effect of captopril in potassium-depleted rats that received gentamicin is due at least in part to kinin-stimulated renal TXB2 production.

Reduced tolerance for heat stress environments caused by protective lotions.

There have been complaints of excessive heat after applying skin protective lotions. The purpose of this study was to determine if oil-base or alcohol-base protective lotions interfere with the body's cooling mechanisms during moderate work in heat stress conditions, and if so, then to identify the mechanisms. This was accomplished by evaluating the effect of lotions on thermoregulation as measured by rectal temperatures, local sweat rates, and total water losses during exercise at elevated temperatures. In comparison to the control, after about thirty minutes, the skin lotion tests resulted in a more hyperthermic condition, as measured by rectal temperatures.