Evaluation of proteinuria in healthy living kidney donor candidates

BACKGROUND

Evaluation of living kidney donor candidates includes careful assessment for the presence or absence of kidney disease. Kidney donation has been considered to be at least relatively contraindicated if urinary total protein excretion is above the normal range. However, at the present time, there is no uniformly accepted level of urine total protein excretion that would exclude donation. Albumin excretion instead of total protein excretion as a criterion has not previously been evaluated.

MATERIALS AND METHODS

This was a prospective observational study over a 3-year period in a single tertiary care center designed to assess current selection criteria for kidney donation with respect to urine total protein and albumin excretion.

RESULTS

Twenty four percent (25 of 105) of healthy adult kidney donor candidates had elevated urinary total protein excretion rates (150 to 292 mg/24 h). Of these 105 candidates, 39 had simultaneous measurements of both urinary total protein and albumin. Although one-third (13/39) had elevated 24-hour urine total protein values, none had elevated urine albumin excretion.

CONCLUSION

Measurement of albumin, the most common single protein found in urine, appears to be helpful in the evaluation of proteinuria in donor candidates. Many healthy adult kidney donor candidates have mildly elevated total protein excretion but normal albumin excretion. We believe that such patients should not be excluded from donation.

Paecilomyces peritonitis: case report and review of the literature

While filamentous fungi are a rare cause of peritonitis in peritoneal dialysis patients, there is increasing recognition of Paecilomyces species as pathogens in such patients. We herein report a case of fungal peritonitis secondary to the filamentous Paecilomyces variotii species. The patient had a long and ultimately fatal course of illness despite catheter removal, discontinuation of peritoneal dialysis, recurrent intraabdominal abscess drainage, and prolonged courses of antifungal therapy. Our experience with this case and a review of the literature suggests that infection with this fungus can cause substantial morbidity and is probably best treated with prompt catheter removal, aggressive antifungal therapy and vigilant observation for complications.

High glucose decreases matrix metalloproteinase-2 activity in rat mesangial cells via transforming growth factor-beta1

Diabetic nephropathy is characterized by accumulation of mesangial matrix. Glucose-induced inhibition of matrix-degrading enzymes such as collagenases is believed to contribute to matrix accumulation. We have previously demonstrated that 72 kDa type IV collagenase activity is decreased in the rat mesangial cells cultured in high glucose media [Diabetes 1995;44:929-935]. The present studies were designed to investigate if the cytokine transforming growth factor-beta1 (TGF-beta1) mediates this effect of glucose. Type IV collagenases degrade type IV collagen as well as gelatin (denatured collagen) and are thus also called gelatinases. They belong to the family of matrix metalloproteinases (MMPs); MMP activity is controlled by tissue inhibitors of metalloproteinases (TIMPs). The activity of 72 kDa type IV collagenase, also known as matrix metalloproteinase-2 (MMP-2), was assessed using three methods: (1) fluoresceinated gelatin degradation assay to detect free enzyme activity (activity which is present in excess of TIMP-inhibited activity); (2) zymography to measure total (free + TIMP-bound) enzyme activity; (3) ELISA using specific antibodies to measure MMP-2 levels. TGF-beta1 and TIMP-2 levels were also determined by ELISA. Incubation of primary cultures of rat mesangial cells for 5 days in 30 vs. 5 mM glucose resulted in a 3-fold increase in production of total TGF-beta1, a significant decrease in MMP-2 activity and immunoreactive MMP-2 levels, and an increase in TIMP-2 levels. Addition of exogenous TGF-beta1 to mesangial cells incubated in 5 mM glucose replicated the high glucose effect by producing a significant decrease in MMP-2 levels with a concurrent increase in TIMP-2 levels. Furthermore, glucose-induced inhibition of MMP-2 activity was completely blocked by neutralization of TGF-beta1 with anti-TGF-beta1 antibody. We conclude that the decrease in MMP-2 activity induced by glucose loading is mediated via TGF-beta1.

Transjugular renal biopsy in patients with liver disease

Although transjugular renal biopsy has been used extensively in Europe, experience with its use in the United States has been limited. We report 25 patients who underwent both transjugular liver and renal biopsies in the same sitting and 4 patients who underwent only a transjugular renal biopsy. All 29 patients had both liver disease and renal abnormalities. Each patient was also believed to have a relative or absolute contraindication to a percutaneous renal biopsy (usually in the form of a bleeding abnormality). Transjugular renal biopsy yielded a quantity of tissue sufficient for diagnosis in all but 1 patient. The mean number of glomeruli obtained per biopsy was 19.4 +/- 12.2 (SD). Pathological diagnoses found were tubular injury in 5 patients, membranoproliferative glomerulonephritis in 5 patients, nephrosclerosis in 3 patients, diabetic nephropathy in 2 patients, immunoglobulin A (IgA) nephropathy in 2 patients, minimal change disease in 2 patients, end-stage renal disease in 2 patients, nonspecific changes in 1 patient, early glomerulosclerosis in 1 patient, tubular atrophy only in 1 patient, and normal renal histological characteristics in 4 patients. One patient with suspected IgA nephropathy had no histological diagnosis established because of a lack of glomeruli in the biopsy specimen. There were no instances of major bleeding from the perirenal area; however, a small perirenal hematoma was identified in 3 patients by postbiopsy computed tomography or sonography. Thus, based on our experience, transjugular renal biopsy appears to be a safe and effective procedure for establishing a histological diagnosis and is an attractive alternative biopsy method for patients with advanced liver disease and contraindications to conventional percutaneous renal biopsy.

Metabolic alkalosis in a hemodialysis patient after ingestion of a large amount of an antacid medication

A maintenance hemodialysis patient developed metabolic alkalosis in the absence of vomiting or nasogastric suction. The cause of the metabolic alkalosis was ingestion of an exogenous alkali in the form of Bromoseltzer. The metabolic alkalosis improved with hemodialysis using a low-bicarbonate bath.

Management of hypophosphatemia induced by high-flux hemodiafiltration for the treatment of vancomycin toxicity: intravenous phosphorus therapy versus use of a phosphorus-enriched dialysate

Intensive high-flux hemodiafiltration is often used in the management of vancomycin toxicity. We describe two patients who developed hypophosphatemia as a consequence of this form of therapy. The first patient was treated with an intravenous phosphorus infusion. For the second patient, hypophosphatemia was corrected, during hemodiafiltration, with the use of a phosphorus-enriched dialysate. The latter dialysate was prepared by adding sodium phosphate salts to the "base concentrate" of a dual-concentrate, bicarbonate-based dialysate delivery system. This simple method was more efficient than intravenous therapy in ameliorating the hypophosphatemia secondary to aggressive hemodiafiltration treatment.

Role of angiotensin II in diabetic nephropathy

Considerable evidence suggests that the intrarenal renin-angiotensin system plays an important role in diabetic nephropathy. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (Ang II) receptor blockers (ARBs) can attenuate progressive glomerulosclerosis in disease models and can slow disease progression in humans. Because agents that interfere with Ang II action may decrease glomerular injury without altering glomerular pressures, it has been suggested that Ang II has direct effects on glomerular cells to induce sclerosis independent of its hemodynamic actions. To study nonhemodynamic effects of Ang II on matrix metabolism, many investigators have used cell culture systems. Glucose and Ang II have been shown to produce similar effects on renal cells in culture. For instance, incubation of mesangial cells in high-glucose media or in the presence of Ang II stimulates matrix protein synthesis and inhibits degradative enzyme (e.g., collagenase, plasmin) activity. Glucose and Ang II also can inhibit proximal tubule proteinases. Glucose increases expression of the angiotensinogen gene in proximal tubule cells and Ang II production in primary mesangial cell culture, which indicates that high glucose itself can activate the renin-angiotensin system. The effects of glucose and Ang II on mesangial matrix metabolism may be mediated by transforming growth factor-beta (TGF-beta). Exposure of mesangial cells to glucose or Ang II increases TGF-beta expression and secretion. Their effects on matrix metabolism can be blocked by anti-TGF-beta antibody or ARBs such as losartan, which also prevents the glucose-induced increment in TGF-beta secretion. Taken together, these findings support the hypothesis that the high-glucose milieu of diabetes increases Ang II production by renal, and especially, mesangial cells, which results in stimulation of TGF-beta secretion, leading to increased synthesis and decreased degradation of matrix proteins, thus producing matrix accumulation. This may be an important mechanism linking hyperglycemia and Ang II in the pathogenesis of diabetic nephropathy.

Removal of Foscarnet by hemodialysis using dialysate-side values

Foscarnet is an antiviral agent widely used in the treatment of cytomegalovirus (CMV) infection. We describe a cardiac transplant patient, who while being maintained with hemodialysis because of tobramycin-induced acute renal failure, was given Foscarnet for disseminated CMV infection. Using dialysate-side clearance methodology, we found the dialyzer clearance of Foscarnet to be in the order of 89 ml/min.

Role of angiotensin II in glucose-induced inhibition of mesangial matrix degradation

Accumulation of mesangial matrix in diabetic nephropathy is caused by increased synthesis and decreased degradation. We have previously demonstrated that incubation in high-glucose medium decreases mesangial cell collagenase activity (Diabetes 44:929-935, 1995). Because angiotensin II (AII) is involved in the pathogenesis of diabetic nephropathy, the present studies were performed to determine if AII mediates glucose-induced 1) inhibition of mesangial collagenase activity, 2) mesangial matrix accumulation, and 3) in-crease in transforming growth factor (TGF)-beta1 secretion in mesangial cells. The direct effect of high glucose on AII generation in mesangial cells was also determined. Primary mesangial cells from normal Sprague-Dawley rats were used in all studies. Collagenase activity in cell medium was determined using three methods: 1) zymography; 2) quantitative assay using fluoresceinated gelatin as substrate; and 3) a new enzyme-linked immunosorbent assay (ELISA) that specifically measures 72-kDa collagenase (MMP-2), the principal collagenase synthesized by mesangial cells. Matrix accumulation was estimated by immunoperoxidase assay on cell layers using anti-glomerular basement membrane (GBM) antibodies. TGF-beta1 and AII levels were determined by ELISA. Exposure of mesangial cells to 30 mmol/l glucose (high glucose) vs. 5 mmol/glucose (normal glucose) for 5 days resulted in a significant decrease in collagenase activity (25%) that was normalized by 10(-4) mol/l losartan, a type 1 angiotensin II (AT1) receptor antagonist. High glucose increased anti-GBM binding compared with normal glucose; this effect of glucose was reversed by losartan. Incubation of cells with 30 mmol/l glucose increased total TGF-beta1 secretion, which was also normalized by losartan. Addition of AII (10(-6) mol/l) for 24 h to the culture medium inhibited collagenase activity by 33%; losartan (10(-4) mol/l) blocked this inhibition of enzyme activity. Also, AII decreased collagenase (MMP-2) levels but stimulated TGF-beta1 secretion in mesangial cells. Finally, glucose increased mesangial AII generation in a concentration-dependent manner, with incubation in 30 mmol/l glucose increasing AII by 25% compared with 5 mmol/l glucose. We conclude that glucose increases AII production by mesangial cells, which results in stimulation of TGF-beta1 secretion, decreased matrix degradation, and increased matrix accumulation. These effects of AII are mediated by the AT1 receptor.

Saline-induced dilutional acidosis in a maintenance hemodialysis patient

A patient with end-stage renal disease developed severe hyperchloremic acidosis (venous serum total CO2 level of 10 mmol/L) after treatment with 16 L of isotonic saline. Analysis of this case and published literature indicates that dilutional acidosis may result when very large volumes of isotonic saline are administered intravenously, especially in patients with impaired or absent renal function.

Decreased glomerular proteinase activity in the streptozotocin diabetic rat

Decreased glomerular proteinase activity may contribute to matrix accumulation in diabetes. Male Sprague-Dawley rats were rendered diabetic by injection of streptozotocin (STZ) 65 mg/kg i.v.; age-matched, sham-injected rats served as controls. Glomeruli from diabetic rats 1 month after STZ injection demonstrated significant decreases in collagenase and cathepsin B activities compared to control glomeruli. Treatment with insulin resulted in a slight (but not significant) increase in collagenase activity and normalized cathepsin B activity. We conclude that decreased glomerular collagenase and cathepsin B activities are present in STZ diabetes. These alterations may contribute to mesangial matrix accumulation.

Hemodialysis-induced hypophosphatemia in a normophosphatemic patient dialyzed for ethylene glycol poisoning: treatment with phosphorus-enriched hemodialysis

Hypophosphatemia developed in a normophosphatemic patient after 9 h of hemodialysis therapy (using a phosphate-free dialysate) administered for the treatment of ethylene glycol poisoning. The hypophosphatemia was promptly improved with additional hemodialysis treatment using a phosphorus-enriched dialysate.

Use of a phosphorus-enriched hemodialysate to prevent hypophosphatemia in a patient with renal failure-related pericarditis

We describe a patient who suffered from renal failure-associated pericarditis and underwent daily 3.5-hour hemodialysis treatments for 17 days. The initially elevated serum phosphorus level gradually fell to below normal on days 11 and 12 as a result of the intensive dialytic therapy. Phosphorus was added to the "base concentrate" of a dual-concentrate, bicarbonate-based dialysate delivery system on days 13 to 17. Because of this phosphorus-enrichment, we were able to maintain the patient's serum phosphorus levels within normal limits in spite of continued daily dialysis treatments.

Treatment of acute methanol intoxication with hemodialysis using an ethanol-enriched, bicarbonate-based dialysate

A patient poisoned with methanol was successfully hemodialyzed with an ethanol-enriched, bicarbonate-based dialysate. Along with a concomitant intravenous infusion of ethanol, the ethanol-enriched dialytic procedure was able to maintain an intradialytic plasma ethanol level of 80 to 102 mg/dL. The patient recovered without any sequelae of methanol intoxication.

Correction of hypercalcemia and hypophosphatemia by hemodialysis using a conventional, calcium-containing dialysis solution enriched with phosphorus

We report a woman with hypercalcemia and hypophosphatemia due to primary hyperparathyroidism. Hemodialysis using a phosphorus-enriched, conventional, calcium-containing dialysis solution resulted in the simultaneous correction of hypercalcemia and hypophosphatemia, resulting in a marked improvement of the patient's impaired mental status.

Use of a phosphorus-enriched dialysate to hemodialyze patients with ethylene glycol intoxication

A phosphorus-enriched dialysate was used to intensively hemodialyze two non-uremic and non-hyperphosphatemic patients poisoned with ethylene glycol. As a consequence of the use of such a dialysate, we were able to prevent a fall in plasma inorganic phosphorus levels in these patients in spite of the intensive dialytic therapy.

Obstruction to venous outflow from the left lower extremity after renal transplantation

Three patients with acute massive swelling of the left lower extremity occurring soon after placement of a renal allograft in the left iliac fossa are described. In each patient, obstruction to venous outflow from the left lower limb was documented by venography. We surmise that venous obstruction resulted principally from a combination of extrinsic compression of the left iliac vein by the right common iliac artery or by the allograft, and enhanced venous return from the allograft.

Effect of access recirculation on the modeled urea distribution volume

The effect of vascular access recirculation (AR) on the modeled urea distribution volume (V) is not straightforward. When blood is sampled properly so that it is not admixed with recirculated blood, AR will cause an unexplained increase in V in cases in which AR is present throughout the dialysis session (when AR is limited to the terminal portion of a dialysis session it will cause little or no change in the modeled V). On the other hand, when blood is sampled from the arterial line after simply stopping the pump, postdialysis blood urea nitrogen (BUN) represents arterial line BUN and does not always reflect the BUN in the patient's blood. Under these conditions, when AR is present throughout the dialysis session the modeled V usually shows an unexplained decrease, but V may be unchanged, depending on the urea reduction ratio (URR). We performed a mathematical analysis to predict when V would be decreased and when it would be unchanged when the postdialysis BUN is contaminated with admixed blood. The analysis revealed that when AR is present uniformly throughout the dialysis session, the modeled V should be underestimated when the URR is < or = O.70. When the URR is greater than 0.70, even severe degrees of AR may not be reflected by a change in V. When AR is limited to the terminal part of the dialysis session or when AR increases during the dialysis session, and when V is based on admixed postdialysis blood, underestimation of V will occur in almost all circumstances. In a cross-sectional comparison of modeled to anthropometric volume ratios in eight patients with severe AR and in 11 controls, and in sequential modeling studies in a single patient in whom severe AR developed gradually over time, the volume ratio was low in most, but not all instances when modeled V was based on an admixed postdialysis BUN sample.

Use of a phosphorus-enriched dialysate in a hypercatabolic renal failure patient receiving intensive hemodialysis therapy

An elderly man with end-stage renal disease required intensive hemodialysis therapy because of sepsis-induced hypercatabolism. We were able to prevent the occurrence of hypophosphatemia by using a phosphorus-enriched dialysate during hemodialysis treatments.

Physiological and biochemical response of glomerular epithelial cells to exogenous epidermal growth factor

Epidermal growth factor (EGF) is a growth-promoting cytokine which acts in a paracrine and autocrine fashion on epithelial cells of various tissues. Although previously demonstrated, we have now confirmed the presence of EGF receptors in cultured glomerular epithelial cells (GEC) using radioligand binding studies. Further, the biochemical consequences of EGF receptor activation in this cell type were investigated. In the presence of exogenous EGF, attachment of GEC to plastic was enhanced in a dose-dependent (0.62-10 ng/ml range) manner. At 10 ng/ml of EGF, cell attachment was 5 times higher than in controls. After attachment, there was a 3-fold increase in cell proliferation rate in the presence of 10 ng/ml of EGF. Cells which multiplied and reached confluency in the presence of EGF were 80% larger in volume than in controls. In the presence of EGF, a 70% maximal increase in de novo protein synthetic activity as tested by 3H-leucine incorporation was observed in the dose range of 0.62-10 ng/ml. Further, a dose-dependent increase in extracellular type IV collagenase (gelatinase) as well as in intracellular cathepsins B and D (150 and 260% of control, respectively) activities were noted. It is concluded that GEC respond to exogenous EGF by increasing their protein synthetic rate as well as their catabolic rate, thus resulting in enhanced turnover of macromolecules.

Decreased degradative enzymes in mesangial cells cultured in high glucose media

Abnormalities in extracellular matrix degradation may play a pathogenetic role in diabetic nephropathy. Cultured renal mesangial cells are known to synthesize increased amounts of matrix proteins when incubated in high glucose media (e.g., 30 mmol/l). However, the effect of glucose loading on degradative enzymes is unknown. Primary cultures of rat mesangial cells were grown until confluent in the presence of fetal calf serum (FCS) and insulin (0.67 U/ml). Cells were then cultured for 7 days in plastic wells in either 10 or 30 mmol/l glucose media containing neither FCS nor insulin. Collagenase activity in media were determined by zymography and quantitative spectrofluorometry. Cathepsin B and D activities in cell extracts were measured by spectrofluorometry (using the fluorescent substrate Z-Arg-Arg-7-amido-4-methylcoumarin) and 125I-labeled hemoglobin digestion, respectively. Gelatin-degrading activity of live mesangial cells was also determined. mRNA levels for collagenase IV, cathepsin B, and cathepsin D were determined by Northern analysis. A major band of collagenase activity with a molecular size of 72 kDa was observed in all mesangial cell media. Exposure of cells to high glucose media resulted in significant reductions in collagenase and cathepsin B activities as well as impairment in gelatin-degrading activity. Collagenase IV and cathepsin B and D mRNA levels were also decreased by glucose loading. To exclude the possibility that glucose loading was injurious to cells, 3H-leucine uptake (as a measure of protein synthesis) and membrane alkaline phosphatase activity (as a biochemical marker of viability) were not affected by the high glucose condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of a phosphorus-enriched dialysis solution to hemodialyze a patient with lithium intoxication

A normophosphatemic patient suffering from lithium intoxication was hemodialyzed with a phosphorus-enriched, bicarbonate-based dialysis solution. A post-dialysis fall in plasma phosphorus level was prevented.

Hemodialysis in the diabetic patient with end-stage renal disease

Diabetes mellitus is now the most common cause of end-stage renal disease (ESRD) in the U.S., and the percentage of ESRD patients with diabetes is increasing yearly. One-year survival in such patients is poorer than in those with other etiologies of ESRD but has improved from 64% to 74% over the past decade. However, overall 5-year survival on dialysis is still less than 20% in this population. It is controversial whether hemodialysis or peritoneal dialysis (CAPD, CCPD) is the best choice. Advantages of hemodialysis include its ready availability and convenience for patients, who are frequently incapacitated by blindness, cerebrovascular disease, and/or amputations. However, patients may tolerate dialytic ultrafiltration poorly due to autonomic neuropathy. Maintenance of vascular access is difficult, which may contribute to inadequate dialysis in some patients. Cardiovascular disease remains the most common cause of death. Management of coronary artery disease is difficult because of the high prevalence of silent ischemia. Control of blood pressure is of paramount importance in preventing cardiovascular complications. Improved survival in diabetics who were dialyzed in a more intensive than usual fashion has been reported recently. In addition, much of the difference in survival rates between diabetics and nondiabetics can be accounted for by the poorer nutritional status in the former group. Thus attention to the dose of dialysis administered and assurance of adequate nutrition should result in improved survival of the diabetic patient on hemodialysis.

Can pharmacokinetic dosing decrease nephrotoxicity associated with aminoglycoside therapy

A randomized, controlled clinical trial was performed to determine whether individualized dosing by use of Bayesian pharmacokinetic modeling could decrease nephrotoxicity accosted with aminoglycoside therapy. Two hundred forty-three patients receiving aminoglycosides for suspected or proven infection were randomly assigned to one of three groups: usual physician-directed dosing (Group 1), pharmacist-assisted dosing (Group 2), or pharmacist-directed dosing (Group 3). Dosing in Groups 2 and 3 was based on a Bayesian pharmacokinetic dosing program, whereas Group 1 served as the control group. Individualized dosing resulted in higher mean postinfusion (peak) serum aminoglycoside levels, higher ratios of mean peak level to minimum inhibitory concentration (peak/MIC ratios), and a trend toward lower trough serum levels. Milligrams per dose were higher and number of doses per day was lower in the pharmacist-dosed groups. However, the incidence of nephrotoxicity (> or = 100% increase in serum creatinine) was not different among the three groups (16, 27, and 16% in Groups 1, 2, and 3, respectively). Similarly, severity of toxicity was not affected by the dosing intervention. Risk factors for toxicity included duration of therapy, shock, treatment with furosemide, older age, and liver disease. After controlling for these factors, the dosing intervention still had no effect on nephrotoxicity. It was concluded that Bayesian pharmacokinetic dosing did not decrease the risk of nephrotoxicity associated with aminoglycoside therapy.

Dissociation between pressor sensitivity in vivo and contractile reactivity in vitro to angiotensin II in rats with experimental cirrhosis

1. Decreased pressor sensitivity to angiotensin II occurs in cirrhosis, but the mechanism remains unclear. 2. Angiotensin II dose-response studies were performed in conscious, chronically instrumented cirrhotic and control rats, and angiotensin II concentration-response studies were performed in isolated blood vessels obtained from similar groups of animals. 3. Cirrhotic rats demonstrated a significantly decreased pressor response to angiotensin II (5-80 ng/kg intravenously). However, angiotensin II-generated tension in thoracic aortic rings isolated from cirrhotic rats and studied in vitro was not impaired. These findings are consistent with the concept that circulating vasodilator substances in cirrhosis rather than an abnormality intrinsic to vascular smooth muscle cells are responsible for the decreased pressor sensitivity to angiotensin II in vivo. 4. Pretreatment with the cyclo-oxygenase inhibitor indomethacin (3 mg/kg intravenously) restored pressor sensitivity to angiotensin II to normal, suggesting that cyclo-oxygenase products, possibly vasodilator prostaglandins, may be involved in mediating pressor resistance to this hormone in vivo.

Measurement of naloxone in plasma using high-performance liquid chromatography with electrochemical detection

A new sample preparation technique, solid-phase extraction employing the ion-pair reagent octyl sodium sulfate (OSS), was developed for the selective isolation of nanogram quantities of naloxone from human plasma. Plasma samples containing naloxone, OSS, buffer, and naltrexone (internal standard) were applied to octyldecylsilane (C18) cartridges, and the opiates were eluted with 100% methanol. An extraction efficiency of 90% was achieved. Extracts were then examined by reversed-phase high-performance liquid chromatography with electrochemical detection, with mobile phase composition adjusted to optimize separation and quantitation. An oxidizing potential of +0.93 V resulted in an assay sensitivity of 1.0 ng. Thus, plasma naloxone levels of ca. 20 ng/ml could be readily detected and quantified. The intra-assay coefficient of variation at plasma levels of 80 ng/ml was 7.2%. Plasma naloxone values obtained during a 5-h infusion of the drug (0.24 mg/min) in two normal human subjects were stable and reproducible. Thus, the method herein described is applicable to human studies employing naloxone infusion.

Increasing plasma phosphorus values by enriching with phosphorus the "acid concentrate" of a bicarbonate-buffered dialysate delivery system

Each of seven hypophosphatemic hemodialysis patients was dialyzed with a phosphorus-enriched, bicarbonate-buffered dialysate. The latter was prepared by the introduction of sodium phosphate salts to the "acid concentrate" of a bicarbonate-buffered dialysate delivery system. The patients tolerated the procedure well and their hypophosphatemia improved.

Combined high-efficiency hemodialysis and charcoal hemoperfusion in severe N-acetylprocainamide intoxication

Several extracorporeal techniques have been used to remove N-acetylprocainamide (NAPA), the major metabolite of procainamide, in patients intoxicated with this substance. We report a patient with life-threatening NAPA intoxication who was rapidly and successfully treated with combined high-efficiency hemodialysis and charcoal hemoperfusion. The hemodialyzer and hemoperfusion cartridge were placed in series such that the patient's blood was dialyzed before reaching the cartridge. Overall clearance of NAPA was 153 mL/min, with clearance due to hemodialysis averaging 102 mL/min and that due to hemoperfusion averaging 88 mL/min. Thus, addition of the hemoperfusion cartridge into the extracorporeal circuit resulted in a 50% increase in clearance over that obtainable by high-efficiency hemodialysis alone. In comparison to other modalities, this technique is more effective than either hemodialysis or charcoal hemoperfusion alone and can achieve a more rapid reduction of serum NAPA levels than that observed with slow continuous hemofiltration or hemodiafiltration.

Skin necrosis and protein C deficiency associated with vitamin K depletion in a patient with renal failure

Skin necrosis similar to that induced by warfarin was seen in a patient who had never received the drug but who was vitamin K-deficient due to malnutrition and prolonged treatment with broad-spectrum antibiotics. He also had end-stage renal failure and was receiving prophylactic subcutaneous heparin therapy because of immobilization. His plasma protein C antigen level and, disproportionately, his plasma protein C functional activity were decreased. Both protein C values improved after vitamin K therapy, discontinuation of heparin, and initiation of hemodialysis. We surmise that skin necrosis occurred as a result of protein C deficiency caused by vitamin K depletion. Production of abnormal (descarboxy) protein C/protein S due to vitamin K deficiency and increased protein C inhibitory activity associated with renal failure and/or heparin administration may have contributed to the clinical picture. This rare but serious complication of a relatively common disorder, viz., vitamin K deficiency, reinforces the importance of vitamin K supplementation in malnourished patients who receive long-term antibiotic maintenance therapy.

Naloxone increases water and electrolyte excretion after water loading in patients with cirrhosis and ascites

Endogenous opioids may be involved in the pathogenesis of ascites and edema in patients with liver cirrhosis. We administered the opioid antagonist naloxone (5 mg bolus followed by a 0.06 mg/min infusion) to eight male patients with alcoholic cirrhosis and ascites and to five healthy age- and sex-matched control subjects and determined the effects of naloxone on water and electrolyte excretion after a nonsustained water load (20 ml/kg). In comparison with saline vehicle infusion carried out in the same subjects, naloxone administration resulted in a 50% increase in urine output and creatinine clearance and twofold increases in sodium and potassium excretion in patients with cirrhosis. Fractional sodium and potassium excretion, minimal urinary osmolality, plasma vasopressin and aldosterone levels, arterial blood pressure, and heart rate were not affected by naloxone treatment. The diuretic effect of naloxone was not observed in control subjects. Plasma naloxone levels were about six times higher in patients with cirrhosis than in control subjects (probably because of impaired metabolism of the drug) but only a weak correlation was found between drug levels and the degree of diuresis observed. The diuretic effect of naloxone may be related to an increase in glomerular filtration rate, possibly in conjunction with altered tubular reabsorption.

Asymptomatic, nonketotic, severe hyperglycemia with hyponatremia

We describe five patients with asymptomatic, nonketotic, severe hyperglycemia (serum glucose concentrations between 45.8 and 92 mmol/L) in the face of renal insufficiency are described. As opposed to most of the previously described patients with hyperglycemic, nonketotic, hyperosmolar coma, our patients were hyponatremic. The lack of symptoms in our patients may be related to the absence of cerebral cellular dehydration. Aggressive treatment of hyperglycemia in such patients is unnecessary. Attention to the serum sodium level as well as to the serum glucose concentration will allow recognition of this clinical entity.

Colon-cancer screening in dialysis patients

The usefulness of colon-cancer screening using stool-guaiac testing has been established in large control populations, but not in dialysis patients. In 72 asymptomatic dialysis patients [51 treated with hemodialysis (HD), and 21 with peritoneal dialysis (PD)] who underwent outpatient stool occult blood testing, the test result was positive in 11 (15%) patients (8 HD and 3 PD). Eight of the 11 were investigated further by colonoscopy and, when deemed necessary by the treating physician, esophagogastroduodenoscopy and/or barium enema were also performed. A site of active bleeding was identified in three of the eight patients (hemorrhoids, telangiectasia, ulcerative colitis). In each of the five other patients, potentially bleeding lesions were identified: colonic polyps (two malignant and two benign) in four patients. Barrett's esophagus in one, diverticulosis in two, and colonic vascular deformities in two. These results were compared with those of a large ongoing fecal occult blood screening program in which the prevalence of positive stool occult blood tests is 5% and in which 42% of the positive patients have colonic neoplasms. Thus, although the baseline incidence of positive guaiac tests may be higher in dialysis patients than in nonuremic controls, our results suggest that stool guaiac testing of dialysis patients may not only be useful in detecting colonic polyps, but may also identify other previously unsuspected causes of gastrointestinal bleeding.

Demonstration of Fabry's disease deposits in placenta

Involvement of the placenta by glycosphingolipid deposits in Fabry's disease has not been previously reported. We describe the presence of such deposits in the maternal half of a placenta obtained from a heterozygous carrier of the disease.

Predicting need for surgical drainage of pericardial effusion in patients with end-stage renal disease

The best approach to treatment of pericarditis accompanied by substantial pericardial effusion in end-stage renal disease (ESRD) patients is unknown. In a review of our experience, we found that ESRD patients with moderate-to-large or large (circa 250 mL or larger) pericardial effusions usually failed to improve with intensive dialysis and ultimately required surgical drainage of the effusion. Multivariate analysis revealed that effusion size was by far the most important factor predicting need for surgery. Since early pericardial drainage obviates the risk of sudden tamponade, we recommend that surgery without prior intensive dialysis therapy be considered in such patients.

Role of prostaglandins and thromboxane in the control of renal hemodynamics in experimental liver cirrhosis

Although there is considerable evidence that vasodilator prostaglandins such as prostaglandin E2 (PGE2) modulate renal hemodynamics in liver cirrhosis, the role of the vasoconstrictor thromboxane A2 (TXA2) is controversial. We measured renal hemodynamics and glomerular eicosanoid production in cirrhotic and control rats. Renal plasma flow, as estimated by para-aminohippurate clearance (CPAH) and glomerular filtration rate, as determined by inulin clearance (CIN), were comparable between groups; glomerular production of PGE2 and TXA2 (estimated by the metabolite thromboxane B2 [TXB2]) was slightly but not significantly higher in cirrhotic than in control rats (PGE2: 1060 +/- 142 pg/mg glomerular protein vs 854 +/- 288 pg/mg glomerular protein; TXB2: 782 +/- 103 pg/mg glomerular protein vs 468 +/- 104 pg/mg glomerular protein). Addition of serum from cirrhotic rats to the incubation media failed to increase eicosanoid production in glomeruli obtained from either cirrhotic or control rats. Cyclooxygenase inhibition with 5 mg/kg indomethacin, a dose sufficient to result in a 68% inhibition of glomerular PGE2 synthesis, decreased both CPAH (from 6.59 +/- 0.69 ml/min to 4.52 +/- 0.67 ml/min, p less than 0.05) and CIN (from 1.34 +/- 0.16 ml/min to 0.68 +/- 0.07 ml/min, p less than 0.01) in cirrhotic rats. Thromboxane synthesis inhibition with 1 mg/kg UK-38485, which resulted in an 84% decrease in glomerular TXB2, did not significantly affect either CPAH or CIN; however, there was a strong trend toward improvement in CIN (from 1.23 +/- 0.11 ml/min to 1.43 +/- 0.15 ml/min (0.05 less than p less than 0.1). Neither drug affected renal hemodynamics in control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of diltiazem and hydrochlorothiazide for treatment of patients 60 years of age or older with systemic hypertension

This randomized, double-blind, parallel design trial compared the efficacy and safety of monotherapy with either sustained-release diltiazem or hydrochlorothiazide in 61 men greater than or equal to 60 years of age with a diastolic blood pressure (BP) between 94 and 104 mm Hg. BP, heart rate, laboratory blood and urine tests, left ventricular wall thickness and mass index (as estimated by M-mode echocardiography) and rate and type of ventricular premature complexes (via ambulatory electrocardiographic monitoring) were determined before, during and after drug treatment. Both drugs produced highly significant (p less than 0.001) decreases in supine and upright systolic and diastolic BP. The mean dosages of diltiazem and hydrochlorothiazide used were 260 and 52 mg/day, respectively; at these dosages, 80% of diltiazem-treated versus 71% of hydrochlorothiazide-treated patients achieved goal reduction in BP (supine diastolic BP reduction of greater than 10 mm Hg and to less than 90 mm Hg). Both drugs were well tolerated, although hydrochlorothiazide therapy was associated with multiple biochemical abnormalities not seen with diltiazem. Neither drug affected left ventricular mass index or the rate of ventricular ectopic activity. Diltiazem and hydrochlorothiazide are both effective and safe agents when used as monotherapy in older patients with systemic hypertension unaccompanied by other clinically significant cardiovascular disease.

Cefoperazone in the treatment of peritonitis in continuous ambulatory peritoneal dialysis patients

Cefoperazone is a third-generation cephalosporin that is active against a broad spectrum of gram-positive and gram-negative bacteria. We added this antibiotic to peritoneal dialysis solution at a concentration of 62.5 mg/L to treat peritonitis in six continuous ambulatory peritoneal dialysis (CAPD) patients. Serum drug concentrations were obtained at 0, 0.5, 1, 2, 4, and 24 h after instituting antibiotic therapy. Rapid uptake by blood of the antibiotic across the peritoneal membrane occurred when the latter was inflamed. Adequate bactericidal serum levels for many bacteria were obtained in less than 4 h. Cefoperazone effectively eradicated peritonitis in all patients.

Hyponatraemia in quadriplegic patients

1. Studies were performed in five hyponatraemic (plasma sodium 129 +/- 1.6 mmol/l; plasma osmolality 268 +/- 3.0 mosmol/kg) quadriplegic patients in order to elucidate its aetiology. Five age- and sex-matched healthy subjects served as controls. 2. Daily urine volumes were high (4454 +/- 624 ml) in the quadriplegic patients secondary to habitually increased fluid intake. 3. All quadriplegic patients had suppressed plasma arginine vasopressin levels (less than 0.8 pmol/l) and were able to form dilute urine after a water load (20 ml/kg). However, free water clearance and the ability to excrete the water load were frequently impaired, and these defects were associated with reductions in both osmolar clearance and delivery of filtrate to the distal diluting sites of the nephron. 4. During hypertonic saline (5%, w/v, NaCl) infusion, plasma arginine vasopressin rose progressively before plasma osmolality reached the normal range, consistent with a resetting of the osmostat. 5. We conclude that hyponatraemia in quadriplegic patients is related to an intrarenal defect in water excretion and resetting of the osmostat coupled with increased fluid intake.

Heparin-associated thrombocytopenia in maintenance hemodialysis patients

Thrombocytopenia associated with the presence of a heparin-dependent platelet aggregating factor developed in two patients after hemodialysis with heparin. It resolved in one patient after heparin was stopped; but persisted in the other during a two-week heparin-free period and intermittently thereafter. We suggest that when heparin causes thrombocytopenia in dialysis patients the heparin should be stopped whenever possible, but this may not be necessary in all patients.

Involvement of renal allograft by Fabry's disease

A man with Fabry's disease received a renal allograft from a heterozygous sister. Renal allograft dysfunction necessitated an allograft biopsy 5.5 years after transplantation. Extensive accumulation of Fabry's disease deposits in the glomeruli, tubules, blood vessels and interstitium was noted.