Ommaya-catheter-related Staphylococcus epidermidis cerebritis and recurrent bacteremia documented by molecular typing.

A 26-year-old woman receiving intrathecal chemotherapy for acute leukemia developed Ommaya-catheter-associated cerebritis and bacteremia caused by two clones of Staphylococcus epidermidis. Genomic fingerprinting of 19 staphylococcal isolates from the cerebrospinal fluid, blood, catheter and skull biopsy was necessary to establish the etiologic diagnosis and to guide medical and surgical therapy.

Low molecular weight proteinuria in human immunodeficiency virus-infected patients.

To determine whether human immunodeficiency virus (HIV) infection is associated with incipient tubular or glomerular defects, we determined the urinary excretion of four low molecular weight proteins (LMWP); beta2-microglobulin (U-beta2-m), cystatin C (U-cyst C), Clara cell protein (U-CC16), and retinol-binding protein (U-RBP), the markers of tubular dysfunction, the excretion of albumin (U-Alb), a marker of glomerular defect, and the excretion of N-acetyl-beta-D-glucosaminidase (U-NAG), a marker of structural damage of the proximal tubular epithelium. Their determinants have been assessed by stepwise regression analysis using as possible predictors age, sex, serum-beta2-m (S-beta2-m), CD4 lymphocyte count, or HIV infection stage and therapy. The study involved 76 HIV-infected patients without renal disease, 56 with S-beta2-m < 5 mg/L (Group B1), 20 with S-beta2-m > or = 5 mg/L (Group B2), and 30 HIV-negative controls. Fourteen patients (18.4%) had no abnormal urinary protein loss, and 62 (81.6%) had elevated urinary excretion of at least one protein (Alb, LMWP, or NAG). A single urinary protein was abnormal in 21 patients (U-beta2-m, n = 9; U-RBP, n = 2; U-CC16, n = 4; and U-Alb, n = 6). At least two LMWP were abnormal without increased U-Alb in 23 patients (12 with increased and 11 with normal U-NAG). Ten patients had an increased urinary excretion of at least one LMWP together with U-Alb (5 with increased and 5 with normal U-NAG). An increased urinary excretion of all proteins was observed in the last 8 patients. The average urinary excretion of all proteins (except cyst C) was significantly higher in HIV than in the control group. As expected, U-beta2-m and the prevalence of abnormal U-beta2-m values were higher in the B2 than in the B1 group (P = 0.0001), whereas the average urinary excretion and the prevalence of elevated values of Alb, LMWP (except beta2-m) or NAG were the same in both HIV groups. By stepwise regression analysis, age emerged as a significant determinant of urinary excretion of beta2-m and CC16, whereas male sex was associated with increased U-CC16. S-beta2-m, CD4-lymphocyte count, or HIV infection stage emerged as significant determinants only for U-beta2-m as a consequence of a close correlation between S-beta2-m and either HIV infection stage (r = -0.52, P = 0.0001), or CD4 count (r = -0.45, P = 0.0002). Over 80% of HIV-infected patients without overt renal disease have evidence of glomerular permeability defects or tubular dysfunction, whatever the stage of the disease. U-Alb, RBP, and CC16 appear as the most sensitive and reliable early markers of these abnormalities. Their cause and prognostic value remain to be determined.

Development and validation of new screening tests for nephrotoxic effects.

Within the framework of an European Commission-funded project, groups of industrial workers exposed to heavy metals (cadmium, mercury and lead) or solvents were studied together with corresponding control groups. Eighty-one measurements were carried out on urine and serum samples and the scientific results together with individual questionnaire information were entered into a central database. Data obtained was assessed centrally and individually in subsidiary studies. The measurable contributions were assessed either singly or in combination, of smoking, gender, metal exposure and site, to nephrotoxicity. The potential value of each test as an indicator of nephrotoxicity was then assessed on the basis of sensitivity and specificity. A number of new tests including prostaglandins and for extracellular matrix components were investigated as well as established tests for renal damage and dysfunction. The data obtained from this comprehensive study emphasises the value of noninvasive biomarkers for the early detection of nephrotoxicity due to environmental toxins. The urinary profile varied with the type of environmental/occupational toxin. By careful selection of a small panel of markers they can be used to indicate the presence of renal damage, the principal region affected, and to monitor the progress of disease and damage. Biomarkers were also used to confirm and tentatively establish safe exposure levels to nephrotoxins.

Factors influencing serum levels and peritoneal clearances of low molecular weight proteins in continuous ambulatory peritoneal dialysis.

To identify the factors influencing the serum concentrations and the peritoneal clearances of low molecular weight proteins (LMWP), fourteen patients on continuous ambulatory peritoneal dialysis (CAPD) for 1 to 57 (mean 9.4) months were examined. LMWP [Beta 2-microglobulin (Beta 2m, molecular wt 11.8 kD), cystatin C (cyst C, molecular wt 13.2 kD), Clara cell protein (CC16, molecular wt 15.8 kD), retinol-binding protein (RBP, molecular wt 21 kD) and alpha 1-microglobulin (Alpha 1m, molecular wt 33 kD)] and high molecular weight proteins (HMWP) [albumin (Alb, molecular wt 66 kD), immunoglobulins (IgG, molecular wt 170 kD and IgM, molecular wt 600 kD) and alpha 2-macroglobulin (Alpha 2m, molecular wt 718 kD)] were determined by latex immunoassay in the serum and dialysate collected during the peritoneal equilibration test (PET) with 2.27% dextrose (N = 14), and in dialysate from 56 standard exchanges, performed the day preceding PET, with 1.36% (N = 21), 2.27% (N = 23) and 3.86% (N = 12) dextrose. Determinants of serum concentrations and transperitoneal clearances of the proteins were traced by stepwise regression analysis using as possible contributors age, sex, residual diuresis, duration of the therapy (for serum concentrations), molecular radius of the protein and peritoneal membrane characteristics (for peritoneal clearances). LMWP serum concentrations were markedly increased whereas serum concentrations of HMWP were within the normal range. Residual diuresis, age and duration of dialysis emerged as significant determinants of serum concentration of some proteins, whereas transperitoneal clearance was dependent mainly on the size of the protein and, only for HMWP, on the dwell time. Residual diuresis was inversely related to the serum concentrations of four LMWP. Age was negatively correlated to the serum concentrations of beta 2m, CC16 and RBP. RBP and Alb were the only proteins whose serum concentration significantly decreased with time on CAPD. The relationship between peritoneal clearance and M(r) shows two slopes suggesting the existence of two populations of pores in the peritoneal capillary wall: small pores of about 20 to 25 A radius and large pores exceeding 100 A radius. A long dialysis cycle is associated with significant loss of HMWP only. Daily peritoneal protein losses, in mg (mean +/- SD), were as follows: Beta 2m 43.4 +/- 4.5; cyst C 9.6 +/- 1.8; CC16 1.8 +/- 0.3; RBP 58.9 +/- 11.1; Alpha 1m 149.5 +/- 15.7; Alb 6570 +/- 530; IgG 750 +/- 111; IgM 46.4 +/- 14.9; and alpha 2m 67.0 +/- 12.7. In conclusion, LMWP concentrations in the serum of patients on CAPD were markedly increased and influenced mainly by patient-related factors (residual diuresis and age). Serum albumin and RBP declined with the duration of dialysis. Peritoneal protein loss was determined by the size of the protein and, for large proteins, by the dwell time. The peritoneum behaves as a membrane with at least two populations of pores.

Low molecular weight proteinuria in Chinese herbs nephropathy.

Urinary excretion of five low molecular weight proteins (LMWP) [beta 2-microglobulin (beta 2m), cystatin C (cyst C), Clara cell protein (CC16), retinol-binding protein (RBP) and alpha 1-microglobulin (alpha 1m)], albumin and N-acetyl-beta-D-glucosaminidase (NAG) were quantified in 16 patients who followed a weight reduction program which included Chinese herbs, which have been incriminated in the genesis of Chinese herbs nephropathy (CHN). An additional group of four patients transplanted for CHN were investigated. Urinary data were obtained for comparison purpose in five groups of proteinuric patients: two groups with normal serum creatinine (SCr) and glomerular albuminura [12 patients with diabetes mellitus and microalbuminuria (DN), 10 patients with primary nephrotic syndrome (NS)]; two groups with normal SCr and toxic nephropathy [6 patients with analgesic (AN), 9 patients with cadmium nephropathy (CdN)]; and one group of seven patients with glomerular diseases and increased SCr (GN). Patients were classified according to serum level S beta 2m to take into account the possibility of overflow proteinuria at S beta 2m > or = 5 mg/liter. Three patients (CHN0) with a S beta 2m < 5 mg/liter, had a normal urinary protein pattern including NAG and a normal S beta 2m. Eight patients (CHN1) with a S beta 2m < 5 mg/liter had various abnormalities of their urinary protein pattern. In four of them (CHN1a) only beta 2m, RBP and CC16 were increased while total proteinuria and SCr were normal. In the other four (CHN1b and c) albumin, cyst C, alpha 1m and NAG were also elevated, while total proteinuria and SCr were moderately raised. Five patients (CHN2) with a S beta 2m > or = 5 mg/liter had a markedly increased excretion of all LMWP, albumin and NAG (CHN1 vs. CHN2, P < 0.05) as well as a further increase in total proteinuria and SCr. The urinary LMWP/albumin concentration ratio was strikingly higher in CHN patients than in patients with glomerular albuminuria (CHN1 vs. DN and NS, P < 0.01) or moderate renal failure with elevated S beta 2m level (CHN2 vs. GN, P < 0.01), confirming the existence of a tubular proteinuria independent of glomerular albuminuria or overflow proteinuria. A similar proteinuria pattern was present in the two toxic nephropathies (CdN and AN). This pattern was no longer recognizable after transplantation. In conclusion, CHN exhibits various profiles of tubular proteinuria which are the hallmarks of the disease. This pattern is still detectable in patients with renal failure and/or glomerular albuminuria. It is identical to that observed in cadmium and analgesic nephropathies. It does not recur after transplantation. Its most sensitive and reliable marker is a raised urinary level of CC16 or RBP.

Determinants of the serum concentrations of low molecular weight proteins in patients on maintenance hemodialysis.

Factors influencing the serum concentrations of low molecular weight proteins (LMWP) during long-term hemodialysis were studied in 112 patients undergoing dialysis for an average of 61.1 months (range 1 to 243). These patients were treated with AN69, cellulose acetate, cuprophan or polysulfone membranes. The following proteins were measured in serum before and after a four hour dialysis session: cystatin C (CYST C), beta 2-microglobulin (beta 2 m), Clara cell protein (CC16) and retinol-binding protein (RBP). Predialysis levels of the four proteins were markedly elevated. In simple regression analysis, pre-dialysis serum concentrations of beta 2 m and CC16 weakly correlated with the duration of dialysis treatment, but these relations completely disappeared when a stepwise regression analysis was performed using as predictors age, sex, residual diuresis, body weight loss (BWL), duration of hemodialysis and the type or ultrafiltration coefficient (UFC) of the membranes. The only significant determinants which emerged from this analysis were the residual diuresis and age which negatively correlated with CYST C, beta 2m and CC16 (residual diuresis only), and sex which influenced CYST C. During the dialysis session, the microproteins underwent changes that were related to their molecular radius, the membrane UFC and the BWL. After adjustment for the latter, high flux membranes (UFC > or = 15 ml/h.m2.mm Hg) allowed up to 50% of CYST C and 25% of beta 2m to be removed. No significant elimination of CC16 and RBP was evident. On the basis of these results, we estimated the effective pore radius of high flux membranes between 1.5 and 1.7 nm and that of low flux membranes as below 1.5 nm.(ABSTRACT TRUNCATED AT 250 WORDS)