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Few studies are available with sufficient sample size to accurately describe the prevalence of low ankle-brachial index (ABI) in patients at 'non-high' cardiovascular (CV) risk. The aim of this study was to evaluate the prevalence of asymptomatic peripheral arterial disease (PAD), as determined by using ABI, in this patient population. A non-interventional, cross-sectional, pan-European study was conducted in patients with ≥1 CV risk factor in addition to age, evaluating the prevalence of asymptomatic PAD (ABI ≤ 0.90). Secondary objectives included assessing the prevalence and treatment of CV risk factors. Patients were consecutively recruited during scheduled visits to the physician's office, or were randomly selected by the physician from a list of eligible patients. Patients with diabetes were excluded as this condition was deemed to be a secondary prevention risk. 10,287 patients were enrolled (9,816 evaluable: mean age 64.3 years; 53.5% male). Prevalence of asymptomatic PAD was 17.8% (99% CI 16.84-18.83). Factors significantly associated with asymptomatic PAD included hypertension, age, alcohol intake, family history of coronary heart disease, low levels of high-density lipoprotein-cholesterol, and smoking (p < 0.0001). Patients treated with statins were significantly less likely to have asymptomatic PAD than those who were not (odds ratio 0.62; 95% CI 0.50-0.76; p < 0.0001). Asymptomatic PAD was highly prevalent in patients with non-high CV risk, the majority of whom would not typically be candidates for ABI assessment. These patients should be carefully screened, and ABI measured, so that therapeutic interventions known to diminish their increased CV risk may be offered.

The interaction of vasopressin with prostaglandins were examined in the toad bladder by determining water flows, cAMP levels, and cAMP-dependent protein kinase activity. Both water flow and activation of cAMP-kinase in response to vasopressin were enhanced after prostaglandin inhibition, consistent with inhibition of vasopressin-induced cAMP generation by endogenous prostaglandins. On the other hand exogeneous PGE stimulated cAMP generation. PGE1 (10(-7) M) alone did not increase water flow but activated kinase more than vasopressin only. Addition of PGE1 (10(-7) M) and vasopressin inhibited water flow as compared with vasopressin along but increased the kinase ratio above that with vasopressin only. PGE2 (10(-5) M) increased the cAMP content and kinase ratio even more than vasopressin but again resulted in no water flow. Addition of vasopressin and PGE2 (10(-5) M) increased water flow but did not alter cAMP content or the kinase ratio compared with PGE2 alone. Similar results were obtained with PGE1. Accordingly, prostaglandin dissociates cAMP levels and kinase ratio from the hydroosmotic response, suggesting that PGE2 inhibits steps distal to cAMP. Consistent with this, in bladders pretreated with naproxen or meclofenamate, PGE2 (10(-8) to 10(-6) M) inhibited the response to submaximal doses of cAMP (5 mM) or 8-bromo-cAMP (0.03 mM). Furthermore, pretreatment with naproxen significantly enhanced the response to cAMP (5 mM). These studies provide evidence for vasopressin-PGE interaction at the site of cAMP generation and also at a step(s) unrelated to cAMP generation.

Objective In view of the limitations of albumin in peritoneal dialysis (PD), we set out to evaluate whether total lymphocyte counts (TLC) could serve as a better prognostic indicator. We were also interested in how these parameters might differ between PD and hemodialysis (HD) patients. Design In a retrospective study, we reviewed 113 charts from our dialysis unit. All laboratory analyses were performed by the Department of Clinical Pathology of the Nassau County Medical Center, using standard procedures. Intact parathyroid hormone (PTH) was sent out to Nichols Laboratories. Setting All patients originated from the renal clinic at Nassau County Medical Center, a 612 bed public hospital. Patients The 38 PD and 75 HD patients selected had been receiving dialysis for at least 12 months and up to 3 years. The PD patients received either continuous ambulatory and/or cycler PD. For the survivors, the averages of their routine chemical analyses were considered their representative values. For the nonsurvivors, the most recent laboratory values prior to their end point were considered. Main Outcome Measures Mortality or apparent malnutrition leading to transfer to HD represented the end points for PD patients. Mortality alone was used as the end point for HD patients. Results Within the PD population, serum albumin was not significantly lower in nonsurvivors compared to survivors, while the TLC was significantly lower in nonsurvivors (1277 ± 146/mm3 vs 2249 ± 236/mm3, p = 0.0036). The HD population demonstrated a significant difference in both TLC and serum albumin levels between its two prognostic groups; albumin was the better discriminator. Nonsurvivors had a 20% lower serum albumin than did the survivors (27.0 ± 1.6 g/L vs 34.0 ± 0.5 g/L, p = 0.0001). Patients on PD had a higher TLC than those on HD ( p = 0.0001). Conclusions In the HD population, but not in the PD population, both serum albumin and TLC were significantly higher in the group that survived. Serum albumin is a more powerful discriminator of mortality in the HD population, while TLC is a better discriminator of mortality in the PD population. For uncertain reasons, PD patients have a higher TLC than those on HD.

Vsopressin activates a number of transport systems in the toad bladder, including the systems for water, urea, sodium, and other small solutes. Evidence from experiments with selective inhibitors indicates that these transport systems are to a large extent functionally independent. In the present study, we show that the transport systems can be separately activated. Low concentrations of vasopressin (1 mU/ml) activate urea transport with virtually no effect on water transport. This selective effect is due in part to the relatively greater inhibitor action of endogenous prostaglandins on water transport. Low concentrations of 8-bromoadenosine cyclic AMP, on the other hand, activate water, but not urea transport. In additional experiments, we found that varying the ratio of exogenous cyclic AMP to theophylline activated water or urea transport selectively. These studies support the concept of independently controlled systems for water and solute transport, and provide a basis for the study of individual luminal membrane pathways for water and solutes in the accompanying paper.

Oral L-carnitine has been reported to lower the elevated serum myoglobin of renal failure in chronic peritoneal dialysis patients, and intravenous L-carnitine can improve muscle fatigue and cramps in chronic hemodialysis patients. In this study oral L-carnitine, 1.98 g/day, was administered to 6 chronic hemodialysis patients for 8 weeks. Serum levels of myoglobin, creatine kinase, and aldolase, as well as skeletal muscle symptoms (cramps during dialysis, fatigue, and weakness) were monitored biweekly for 12 weeks. Mean baseline serum myoglobin level was 337 +/- 34 ng/mL. By 6 and 8 weeks mean serum myoglobin was 234 +/- 39 and 233 +/- 40 ng/mL, significantly lower by the Friedman test (p < 0.05). Four weeks after carnitine was discontinued, mean serum myoglobin had risen to 320 +/- 118 ng/mL. Serum creatine kinase and aldolase levels were normal throughout the study. All 6 patients noted improvement in muscular symptoms, with maximal effect at 8 weeks, although 2 patients did not improve until 2 to 4 weeks after carnitine was stopped. We conclude that oral L-carnitine may lower serum myoglobin and improve muscle cramps and weakness in hemodialysis patients. The maximal effect of carnitine on myoglobin occurs 2 weeks before the maximal improvement in muscular symptoms.

Intravenous labetolol, a nonselective α- and β-blocking drug, is commonly used to treat severe hypertension. Nonselective β-blockers can cause hyperkalemia, especially in patients with renal failure. One series reported 3 renal transplant patients who had hyperkalemia after labetolol infusion, but none of these patients developed any serious complication. We report a case of life-threatening hyperkalemia (serum [K⁺] 9.9 mEq/l) with ventricular tachycardia and hypotension in a patient on maintenance hemodialysis who received labetolol for a hypertensive emergency. Physicians should be aware of this potentially lethal complication, which is easily preventable.