Mining legacy across a wetland landscape: high mercury in Upper Peninsula (Michigan) rivers, lakes, and fish.

A geographic enigma is that present-day atmospheric deposition of mercury in the Upper Peninsula of Michigan is low (48%) and that regional industrial emissions have declined substantially (ca. 81% reduction) relative to downstate. Mercury levels should be declining.

Ephemeral metapopulations show high genetic diversity at regional scales.

One of the primary questions concerning the long-term preservation of nature and its diversity is the maintenance of genetic diversity. However, despite numerous theoretical investigations, comparative empirical information on how local extinctions influence regional genetic variation does not exist. To our knowledge, this is the first report of an empirical study comparing the genetic variation of permanent vs.

Doppler sonography in the evaluation of corporovenous competence after penile vein ligation surgery.

Doppler ultrasonographic findings in patients after penile vein ligation surgery are described and compared to the results of cavernosometry and cavernosography. Peak systolic and end diastolic velocities were recorded for both cavernosal arteries at 5 min intervals after papaverine injection for a total of 30 min. Peak end diastolic flow rates were compared with cavernosometric and cavernosographic results at 0-10 min, 11-20 min, and 21-30 min.

Investigation of vascular changes following penile vein ligation.

In an effort to characterize the changes in penile vasculature that occur following penile vein ligation, we performed pharmaco-cavernosometry and pharmaco-cavernosography on 20 patients after penile vein ligation for comparison with preoperative studies. Three patients with return of erectile function underwent repeat study: 2 were completely normal and 1 had a mild leak from the deep dorsal vein. The remaining 17 patients had continued complaints of erectile impairment.

Characterization of calcium channel blocker induced smooth muscle relaxation using a model of isolated corpus cavernosum.

Several classes of smooth muscle relaxing agents have proven effective in relaxing cavernosal smooth muscle and useful in the pharmacotherapy of erectile dysfunction. The purpose of this investigation was to determine whether the calcium channel blockers (CCB) relax cavernosal smooth muscle. Thirty-two rabbit cavernosal strips were contracted by electrical field stimulation, and contraction inhibition was tested in response to cumulative doses (10(-8) M.

The watercress glucosinolate-myrosinase system: a feeding deterrent to caddisflies, snails and amphipods.

Watercress (Nasturtium officinale) possesses the glucosinolate-myrosinase system. This system is regarded as a classic example of chemical defense for terrestrial crucifers. Damage of watercress initiates myrosinase-mediated hydrolysis of phenylethyl glucosinolate to a toxic endproduct, phenylethyl isothiocyanate.

The effect of isolated high-energy shock wave treatments on subsequent bacterial growth.

To determine whether high-energy shock waves possess bactericidal potential, ATCC strains of Escherichia coli, Streptococcus faecalis, Pseudomonas aeruginosa and Staphylococcus aureus were suspended in solution at concentrations approximating 10(6) bacteria per milliliter, placed in polypropylene cryovials, and immersed in the water bath of a Dornier HM3 lithotriptor. Each cryovial was then fluoroscopically guided to the epicenter of the f2 focal point and 2000 shocks at 20 kV applied. Suspensions were then serially diluted and colony counts obtained.

Pharmacologically induced erections among geriatric men.

Intracavernous injection of vasoactive drugs for the treatment of erectile impotence has become a standard therapeutic technique. Previous reports detailing experience with this treatment are based on patient populations significantly younger than most patients who suffer from impotence. The geriatric population, which comprises the majority of patients with importance, is unique due to the physical, psychological and social changes associated with the aging process.

Watercress and amphipods Potential chemical defense in a spring stream macrophyte.

We investigated the potential role of defensive chemicals in the avoidance of watercress (Nasturtium officinale) by the cooccurring amphipod,Gammarus pseudolimnaeus at two spring brooks: Carp Creek, Michigan and Squabble Brook, Connecticut. We conducted observations and laboratory experiments on the consumption of watercress, the toxicity of damaged (frozen) watercress, and the toxicity of damage-released secondary chemicals. Field-collected yellowed watercress typically lacked the bite and odor characteristic of green watercress and was consumed byG.

Scale-dependent dynamics: Zooplankton and the stability of freshwater food webs.

The study of freshwater pelagic communities is entering an exciting and controversial phase. Recent efforts to clarify how food web interactions differ from food chain interactions have emphasized the various, often subtle, repercussions of top predators on communities. Predators can modify community structure not only through directly imposed death rates, but also through direct and indirect effects on prey interactions, behavior, life-styles and morphology (e.

Orientometrer for study of insect behavior.

A multidirectional treadmill for the study of insect orientation is described. The movements of an insect throughout 360 degrees can be recorded for periods up to 12 hours. The extent of deviation from randomness serves as a quantitative measure of reaction to a given stimulus.