Nephrotic syndrome: an under-recognised immune-mediated complication of non-myeloablative allogeneic haematopoietic cell transplantation

Nephrotic syndrome (NS) is an extremely rare complication of myeloablative allogeneic haematopoietic cell transplantation (HCT) that usually occurs in association with chronic graft-versus-host disease (C-GVHD). We observed an unexpectedly high incidence of NS in a cohort of 163 consecutive patients undergoing non-myeloablative HCT from a related human leucocyte antigen-compatible donor. Seven patients developed NS at a median 318 d post-transplant (range 119-1203 d; cumulative incidence 6.1%). The median age at onset of NS was 46 years (range 33-59 years); three of the seven patients had no evidence of C-GVHD while four had accompanying limited C-GVHD. At diagnosis, median proteinuria was 16.5 g/24 h (range 3-24 g/24 h). Renal biopsy was performed in four cases and revealed membranous nephropathy. NS was not always associated with other symptoms of C-GVHD, and in contrast to previous reports, usually did not improve with the re-initiation of aggressive immunosuppression, resulting in progressive renal failure necessitating dialysis in three of seven cases. Membranous nephropathy resulting in NS is a previously unrecognised and clinically significant complication of non-myeloablative HCT.

Enzyme replacement therapy in Fabry disease: a randomized controlled trial

CONTEXT

Fabry disease is a metabolic disorder without a specific treatment, caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). Most patients experience debilitating neuropathic pain and premature mortality because of renal failure, cardiovascular disease, or cerebrovascular disease.

OBJECTIVE

To evaluate the safety and efficacy of intravenous alpha-gal A for Fabry disease.

DESIGN AND SETTING

Double-blind placebo-controlled trial conducted from December 1998 to August 1999 at the Clinical Research Center of the National Institutes of Health.

PATIENTS

Twenty-six hemizygous male patients, aged 18 years or older, with Fabry disease that was confirmed by alpha-gal A assay.

INTERVENTION

A dosage of 0.2 mg/kg of alpha-gal A, administered intravenously every other week (12 doses total).

MAIN OUTCOME MEASURE

Effect of therapy on neuropathic pain while without neuropathic pain medications measured by question 3 of the Brief Pain Inventory (BPI).

RESULTS

Mean (SE) BPI neuropathic pain severity score declined from 6.2 (0.46) to 4.3 (0.73) in patients treated with alpha-gal A vs no significant change in the placebo group (P =.02). Pain-related quality of life declined from 3.2 (0.55) to 2.1 (0.56) for patients receiving alpha-gal A vs 4.8 (0.59) to 4.2 (0.74) for placebo (P =.05). In the kidney, glomeruli with mesangial widening decreased by a mean of 12.5% for patients receiving alpha-gal vs a 16.5% increase for placebo (P =.01). Mean inulin clearance decreased by 6.2 mL/min for patients receiving alpha-gal A vs 19.5 mL/min for placebo (P =.19). Mean creatinine clearance increased by 2.1 mL/min (0.4 mL/s) for patients receiving alpha-gal A vs a decrease of 16.1 mL/min (0.3 mL/s) for placebo (P =.02). In patients treated with alpha-gal A, there was an approximately 50% reduction in plasma glycosphingolipid levels, a significant improvement in cardiac conduction, and a significant increase in body weight.

CONCLUSION

Intravenous infusions of alpha-gal A are safe and have widespread therapeutic efficacy in Fabry disease.

Unusual renal features of Lowe syndrome in a mildly affected boy

The oculocerebrorenal syndrome of Lowe (OCRL) is an X-linked disorder characterized by congenital cataracts, mental retardation, and renal tubular dysfunction. The gene responsible for OCRL was identified by positional cloning and encodes a lipid phosphatase, phosphatidylinositol 4,5, bisphosphate [PtdIns(4,5)P2]5-phosphatase, which localizes to the Golgi apparatus and is suspected to play a role in Golgi vesicular transport [Suchy et al., 1995]. In addition to the ocular and renal manifestations, most boys with OCRL have cognitive problems and maladaptive behaviors including tantrums and stereotypies. We report a boy with a history of congenital cataracts and mild developmental delay who was also found to have hematuria with proteinuria but minimal signs of renal tubular dysfunction. Subsequent renal biopsy was compatible with a diagnosis of a noncomplement fixating chronic glomerulonephritis. Despite the atypical renal findings, skin fibroblast analysis for PtdIns (4,5)P2 5-phosphatase was performed, and enzyme activity was low, consistent with the diagnosis of OCRL. Western blot analysis from cell lysates showed the ocrl protein was decreased in size and amount. Our report shows atypical renal features of OCRL in a mildly affected boy. The possibility of OCRL should be considered in boys with cataracts and glomerular disease, even in the absence of renal tubular defects and frank mental retardation usually associated with the syndrome. Am. J. Med. Genet. 95:461-466, 2000. Published Wiley-Liss, Inc.

Chitosan as an enabling excipient for drug delivery systems. I. Molecular modifications

Chitosan was physicochemically modified for its potential use as a matrix for an implantable antibiotic delivery system that could sustain bactericidal concentrations in the vicinity of an implant or prosthesis. Deacetylation and depolymerization of chitosan were implemented in order to increase the number or accessibility of the reactive amino groups on the polymer backbone for better polymer-drug interaction. The deacetylation process involved reaction of particulate chitosan/depolymerized chitosan with alkali. The rate of deacetylation of chitosan was directly proportional to the reaction temperature up to 80 degrees C; beyond 80 degrees C, rapid degradation of the polymer occurred. The depolymerization of chitosan involved acid digestion of the polymer followed by application of mechanical agitation. This depolymerized product, although water insoluble, possessed a molecular weight that was one to two orders of magnitude lower than that of commercially available chitosans. These products not only exhibited improved reactivity, but also showed increased crystallinity when compared with the parent chitosan. The reactivity was found to be inversely proportional to chitosan's molecular weight. The depolymerization and deacetylation treatments afforded formation of chitosan having a greater number of amino groups available for interactions with the anionic actives.

Factors influencing the bioavailability of peroral formulations of drugs for dogs

The oral route is presently the preferred route of drug delivery. Poor oral bioavailability results in variable concentrations of drugs in the plasma and variable pharmacological responses, in addition to higher product costs. The unique canine physiology, anatomy and biochemistry makes designing canine dosage forms a challenging exercise. This article reviews the physicochemical, physiological, pharmacokinetic, pharmacological and formulation factors that can influence the drug availability of the oral formulations in dogs in an effort to provide a source of data to aid development of canine drug products with superior bioavailability.

Controlled-release hydrophilic tablets for individualized theophylline therapy

Directly compressible controlled-release (CR) theophylline tablet formulations with a non-zero-order drug release were prepared using various grades of Methocels. These tablet formulations were employed in the individualization of therapy with the aid of a pharmacokinetic simulation model developed with STELLA II computer software. In vitro drug release data were used to simulate plasma concentration-time (C,t) profiles based on a wide range of previously reported patient pharmacokinetic parameters (clearances of 2-5 L/hr and apparent volumes of distribution of 20-50 L). The simulations indicated that formulations containing low-viscosity Methocels (E4, K4, and K4CR) were suitable for individualizing theophylline therapy. Average steady-state concentrations were well within the therapeutic range of 10-20 micrograms/ml. High-viscosity polymers such as E10CR, K15, and K15CR yielded subtherapeutic concentrations and were deemed unsuitable. Thus, a pharmacokinetic simulation program capable of predicting in vivo C,t profiles (even though theophylline release occurred by a non-zero order) may be useful for individualizing theophylline therapy that involves CR formulations.

Sugar-induced blood pressure elevations over the lifespan of three substrains of Wistar rats

OBJECTIVE

Since the majority of studies concerned with sugar-induced blood pressure elevation have principally been short-term, the present investigation followed the effects of heavy sucrose ingestion on systolic blood pressure (SBP) and related parameters over the lifespan of three substrains of Wistar rats.

METHODS

Two hundred twenty-five rats (75 spontaneously hypertensive rats (SHR), 75 Wistar Kyoto rats (WKY), 75 Munich Wistar rats (WAM) were given one of five diets. The baseline diet in terms of calories derived 32% from sucrose, 33% from protein, and 35% from fat. The remaining four diets derived their calories as follows: a high sugar-low protein diet--52% of calories from sucrose, 15% from protein, and 33% from fat; a high sugar-low fat diet--53% of calories from sucrose, 37% from protein, and 10% from fat; a low sugar-high protein diet--11% calories from sucrose, 56% from protein, and 33% from fat, and a low sugar-high fat--13% of calories from sucrose, 32% from protein, and 55% from fat.

RESULTS

All substrains showed the highest systolic blood pressure when ingesting the two diets highest in sucrose. The highest sugar-induced SBP elevation, which remained over the lifespan of all substrains, was found in SHR. WKY had an intermediate elevation. WAM showed the lowest responses, although the average elevation of 6-8 mm Hg was statistically significant. The following parameters could not be correlated with long-term elevation of SBP; body weight, catecholamine excretion, renal function, and plasma renin activity. Only insulin concentrations correlated: insulin concentrations were consistently higher in the two groups of WKY and WAM consuming the high sucrose diets.

CONCLUSIONS

High dietary sucrose can chronically increase SBP in three substrains of Wistar rats. Increased concentrations of circulating insulin were found in WKY and WAM suggesting that the glucose/insulin system was involved, at least in these two substrains, in the maintenance of high SBP levels during chronic, heavy sugar ingestion.

The perinephric space and renal fascia: review of normal anatomy, pathology, and pathways of disease spread

The perinephric space is a cone-shaped retroperitoneal compartment containing the kidney, adrenal gland, perinephric fat, fibrous bridging septa, and a rich network of perirenal vessel and lymphatics. Perinephric space pathology may originate from within or outside the confines of the perirenal fascia. Most intrinsic perinephric space disease arises from the kidney or adrenal gland, and secondarily involves the perinephric space. Disease originating outside the cone of renal fascia may spread to the perinephric space via lymphatics (i.e., metastatic spread) or by directly transgressing perirenal fascial planes (e.g., invasive tumor or infections). Additionally, infiltrating soft tissue or rapidly accumulating retroperitoneal fluid may travel into or out of the perinephric space via perinephric bridging septa and renal fascia. In this article, we review the normal anatomy of the perinephric space and renal fascia, emphasizing the significance of retroperitoneal interfascial planes and perinephric bridging septa as a potential conduit for retroperitoneal disease spread. This review of normal anatomy and pathways of disease spread serves as background for a discussion of a variety of specific pathologic conditions that may involve the perinephric space and retroperitoneal fascia, including pancreatitis, retroperitoneal hematoma, urinoma, metastatic disease, and perirenal varices.

Use of chitosan in compressed tablets of diclofenac sodium: inhibition of drug release in an acidic environment

The purpose of this study was to evaluate the potential utility of chitosan (I) in inhibiting diclofenac sodium (II) release in the gastric environment from a directly compressible tablet formulation. I, subjected to depolymerization to improve its microcrystallinity and subsequent compressibility, was then used to prepare tablets of II. A full-factorial design was employed to evaluate the effects of degree of N-deacetylation of I, and the pH and ionic strengths, mu, of the dissolution media on drug release. Directly compressible tablets were prepared from admixtures of 25 mg of II, 174 mg of I of various degrees of N-deacetylation (74, 87, and 92%), and 1 mg of magnesium stearate. The in vitro dissolution studies were performed using aqueous buffers (pHs 1.2, 3.8, and 6.8, and mu of approximately 1.0 and 0.1). The slopes of logarithmically transformed cumulative percent released-time curves (from t = 0 to t = 5 hr) were compared. Analyses of variance performed using SAS indicated that the degree of N-deacetylation of chitosan significantly affected drug release at pHs 1.2 and 6.8 (p < 0.0001). An increase in the pH of the dissolution medium resulted in an increase in drug release (p < 0.0001). The ionic strength of the dissolution medium did not significantly affect drug release at any of the pHs studied (p > 0.198). Besides the poor aqueous solubility of II, the two factors possibly affecting the drug release in the acidic environment were (a) the formation of a rate-limiting chitosan gel barrier; and (b) the ionic interaction of II with ionized amino groups of I.

Effect of glycine on cisplatin nephrotoxicity and heat-shock protein 70 expression in the rat kidney

Glycine has been shown to protect against cisplatin (CP) nephrotoxicity in rats and to enhance the in vitro expression of heat-shock protein (hsp) 70 in renal epithelial cells following sublethal heat shock. We hypothesized that the protective effect of glycine against CP nephrotoxicity may be due to an up-regulation of Hsp 70 protein expression. Male Sprague-Dawley rats were divided into 4 treatment groups based upon infusion of glycine and injection of CP or their respective vehicles. At 5 days after treatment animals administered CP alone demonstrated a significant decrease in creatinine clearance compared to baseline (0.77 +/- 0.32 mL/min vs. 3.90 +/- 0.87 mL/min, p < 0.05). Treatment with glycine and CP attenuated this response, with no significant decline seen in creatinine clearance at day 5 compared to baseline (2.25 +/- 0.31 mL/min vs. 3.40 +/- 0.86 mL/min). Semiquantitative histological study revealed a marked decrease in proximal tubular injury at the juxtamedullary and outer medullary regions among animals treated with glycine and CP compared to those animals treated with CP alone. There were no differences in renal cortical and medullary Hsp 70 levels by Western immunoblotting between animals treated with glycine and CP compared to CP alone at 4 h and 5 days after treatment. Immunohistochemical studies of animals treated with CP alone revealed the diffuse presence of Hsp 70 in the cytoplasm of injured and necrotic proximal tubular cells 5 days after treatment. Animals receiving CP and glycine demonstrated a more focal presence of Hsp 70 restricted to injured proximal tubular cells, with no staining of uninjured cells. The protective effect of glycine in CP-induced acute and renal failure in the rat does not appear to be associated with enhancement of Hsp 70 expression.

The clinical characteristics and infectious outcomes of febrile infants aged 8 to 12 weeks

We reviewed 356 consecutive cases of febrile infants aged 8 to 12 weeks who received outpatient evaluation for sepsis over 4 years. Thirty-three infants (9.3%) had a serious bacterial infection (SBI), including bacterial meningitis, bacteremia, urinary tract infection (UTI), and Salmonella enteritis. The SBI rate, which was directly proportional to fever height, was significantly greater for infants with hyperpyrexia (35%) than those with lesser degrees of fever (7.7%) and for infants with peripheral blood leukocytosis (total WBC count > or = 15,000/mm3; 25%) than those with lesser total WBC counts (5.8%). An attending-level physician judged that 67% of infants with SBI appeared to be "well," including five or eight cases (63%) of bacteremia, 14 of 17 cases (82%) of UTI, and all three cases of Salmonella enteritis, whereas all five patients with bacterial meningitis appeared to be "ill." Urinalysis abnormalities indicative of UTI were present in 15 of 17 infants (88%) who had this infection. SBIs are not uncommon in febrile infants aged 8 to 12 weeks and occur significantly more often in those with either hyperpyrexia or peripheral blood leukocytosis.

Endoscopic removal of retained bile duct calculi via T-tube tract

A simple and safe technique for removal of retained bile duct calculi using a flexible fibreoptic choledochoscope and rigid nephroscope via the T-tube tract has been described. The technique allowed removal of large impacted calculi under direct vision without damage to the bile duct.

Monoclonal antibodies to heparan sulfate proteoglycan: development and application to the study of normal tissue and pathologic human kidney biopsies

Monoclonal antibodies (mAbs) (4F2 and 7E12) were prepared against heparan sulfate proteoglycan (HSPG) isolated from bovine glomeruli. Enzyme linked immunosorbent assays (ELISA) and immunoblotting demonstrated that the mABs reacted with HSPG. Indirect immunofluorescence (IF) showed that the mAbs stained renal basement membranes (BMs) and BMs in other organs of normal bovine and human tissues in patterns typical of HSPG. Immunoinhibition studies, and immunoblotting of heparan lyase digested HSPG, indicated that the mAbs recognize HSPG core protein. In kidney biopsies from patients with acute poststreptococcal GN, intact linear glomerular BM (GBM) staining for HSPG was noted despite markedly widened capillary loops. In membranous and in diffuse proliferative lupus GN, loss of HSPG staining was demonstrated at sites of immunodeposition of IgG or C3, while increased staining for HSPG was noted in areas of newly formed GBM. Extensive loss of HSPG was seen in areas of glomerular sclerosis and necrosis. In biopsies from patients with minimal change glomerulonephritis (GN) and mesangioproliferative lupus GN, a normal linear GBM distribution of HSPG was noted. The findings are discussed in the context of current knowledge regarding the pathogenesis of glomerular injury. MAbs to BM HSPG should prove useful for future immunochemical studies, and for the study of diseases of the basement membrane.