Carcinoma of the female urethra

Na(+) entry via store-operated channels modulates Ca(2+) signaling in arterial myocytes

In many nonexcitable cells, hormones and neurotransmitters activate Na(+) influx and mobilize Ca(2+) from intracellular stores. The stores are replenished by Ca(2+) influx via "store-operated" Ca(2+) channels (SOC). The main routes of Na(+) entry in these cells are unresolved, and no role for Na(+) in signaling has been recognized. We demonstrate that the SOC are a major Na(+) entry route in arterial myocytes. Unloading of the Ca(2+) stores with cyclopiazonic acid (a sarcoplasmic reticulum Ca(2+) pump inhibitor) and caffeine induces a large external Na(+)-dependent rise in the cytosolic Na(+) concentration. One component of this rise in cytosolic Na(+) concentration is likely due to Na(+)/Ca(2+) exchange; it depends on elevation of cytosolic Ca(2+) and is insensitive to 10 mM Mg(2+) and 10 microM La(3+). Another component is inhibited by Mg(2+) and La(3+), blockers of SOC; this component persists in cells preloaded with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid to buffer Ca(2+) transients and prevent Na(+)/Ca(2+) exchange-mediated Na(+) entry. This Na(+) entry apparently is mediated by SOC. The Na(+) entry influences Na(+) pump activity and Na(+)/Ca(2+) exchange and has unexpectedly large effects on cell-wide Ca(2+) signaling. The SOC pathway may be a general mechanism by which Na(+) participates in signaling in many types of cells.

Localized urethral cancer in women

The results of treatments for localized carcinoma of the urethra were assessed in 21 consecutive women treated at our institutions over a twenty year period. Only one of the tumors was confined to the distal urethra. Eighty-six percent invaded the periurethral tissues and 24% were known to be associated with regional lymph node metastases. Fifty-seven percent were adenocarcinomas. Five patients refused active therapeutic intervention and expired within one to 30 months following diagnosis. Sixteen patients were treated with extirpative surgery, radiation therapy, or combinations of the two. Four are free of disease at one, four, eleven, and 15 years after treatment. Nine developed pelvic recurrences, two developed pelvic recurrences and distant metastases and one developed distant metastases only from six to 72 months (mean, 19 months) after initial treatment. Eight of these 12 patients died at two to 13 months (mean, 8 months) after secondary treatment, two are alive with residual pelvic tumor, and two are clinically free of disease at 7 and 48 months. Only six patients were known to have distant metastases at the time of death and five of these six had adenocarcinomas. Advanced localized urethral cancer in women is difficult to eradicate and usually fatal.

Magnesium and hypertension

Essential hypertension (EHT) is one of the most common risk factors for cerebrovascular and cardiovascular disease (CVD), which in turn are among the most common causes of death and disability in developed countries. Drug treatment of EHT has proven effective in lessening the risk of CVD, but has attendant risk of side effects, some of which are of risk to the CV system. Thus, increasing attention is being paid to non-drug treatment of EHT, which includes changing the daily intake of such electrolytes as sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg). Decreasing Na intake to control blood pressure (BP) is well established. On the basis of epidemiologic and experimental studies, increasing K and/or Mg intakes, and increasing of decreasing Ca intakes, have each been proposed to have beneficial effects of BP. Presented here is a review of the background data supporting the rationale for adding Mg to the anti-hypertensive regimen. There is evidence that Mg can exert a favorable effect in EHT, particularly when used in combination with K during diuretic therapy.