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Biomedical subjects

W B Lorentz

Publications and source records attributed to W B Lorentz.

At least 19 recordsLinked to original sources
PubMed2005

Peritonitis due to Neisseria mucosa in an adolescent receiving peritoneal dialysis.

Neisseria mucosa is part of the normal nasopharyngeal flora and rarely pathogenic in humans. Reports of serious infections associated with this pathogen are very unusual. A 17-year-old boy with end-stage renal disease due to IgA nephropathy presented with acute, spontaneous, symptomatic peritoneal dialysis-associated peritonitis without reported break in sterility or PD catheter exit site infection. beta-lactamase-negative N. mucosa was isolated from the dialysate effluent. Intraperitoneal antibiotic treatment with cephalothin/gentamicin for 5 days and subsequent ceftriaxone led to complete resolution of the infection. This case demonstrates that "non-pathogenic" Neisseria species can cause clinically severe peritonitis with high intraperitoneal neutrophil counts, elevated C-reactive protein levels in the peritoneal effluent (in the presented case, 27,600/mul and 3.6 mg/l, respectively) and impaired peritoneal membrane transport function. To our knowledge, this is the first case of N. mucosa peritonitis complicating chronic peritoneal dialysis in an adolescent patient.

Adolescent↗
PubMed1993

Immature lecithin/sphingomyelin ratios and neonatal respiratory course.

OBJECTIVE: We hypothesized that the absolute value of an immature lecithin/sphingomyelin ratio, in addition to gestational age and birth weight, contributes significantly to predicting the clinical course of the neonate. The lecithin/sphingomyelin value may therefore enhance clinical decision-making regarding timing of delivery and use of tocolytics in high-risk pregnancies. STUDY DESIGN: One hundred four mother-baby pairs with delivery within 72 hours of an immature lecithin/sphingomyelin determination in the 3-year period immediately before the initiation of surfactant therapy in our hospital were retrospectively reviewed. Stepwise regression was performed for the independent variables of gestational age, birth weight, and lecithin/sphingomyelin values in a linear model to predict total days of respiratory support (oxygen, continuous positive airway pressure, or mechanical ventilation). RESULTS: In the patients without preterm premature rupture of membranes the lecithin/sphingomyelin value was the best predictor of duration of respiratory support (R2 = 0.2426, F = 12.4908, p = 0.011). After gestational age was controlled for, there was a significant inverse correlation between the lecithin/sphingomyelin value and days of respiratory support (F = 4.634, p = 0.031). In the patients with preterm premature rupture of membranes with vaginally collected fluid, however, lecithin/sphingomyelin values did not contribute significantly in predicting duration of respiratory support. Rupture-to-delivery interval and gestational age were the best predictors in this group. CONCLUSION: Although a mature lung profile is the ideal situation, preterm delivery may be indicated in pregnancies complicated by maternal disease or evidence of possible fetal compromise. We conclude that in patients without premature rupture of membranes the absolute value of the immature lecithin/sphingomyelin ratio is a better predictor than gestational age or birth weight of duration of respiratory support and should be considered in timing of delivery.

Amniotic Fluid↗
PubMed1991

C1q nephropathy: a pediatric clinicopathologic study.

We report on 15 children with proteinuria, at the nephrotic level in the majority of cases, who had no histologic glomerular alterations (eight cases), or focal and segmental glomerular scarring with (three cases) or without (four cases) mesangial proliferation. In all cases, immunofluorescence (IF) microscopy showed prominent mesangial C1q deposits with variable amounts of immunoglobulins. Ultrastructurally, most had conspicuous mesangial electron-dense deposits. Cases with no glomerular histologic alterations were histologically indistinguishable from minimal change disease (MCD), yet they uniformly had an unsatisfactory response to oral prednisone. Thus, the presence of immune deposits with a prominent C1q contribution identifies a group of cases that respond poorly to steroids and that, if light microscopy is considered in isolation, might otherwise be designated MCD.

Adolescent↗
PubMed1991

Anaphylaxis and desensitization to the murine monoclonal antibody used for renal graft rejection.

The murine monoclonal antibody muromonab CD3 is currently used to reverse acute renal graft rejection. We report a case of systemic anaphylaxis during a muromonab CD3 infusion despite pretreatment with systemic antihistamines and corticosteroids. Rapid intravenous desensitization was performed the following day without untoward reactions and daily muromonab CD3 infusions were successful in reversing renal graft rejection. A second rapid desensitization to CD3 was performed 1 month later without any complications. Serum muromonab CD3-specific IgG and IgE antibodies were detected in serum samples obtained after the anaphylactic reaction. The anaphylactic reaction to muromonoab CD3 monoclonal antibody could have been due to allergen-specific antibodies noted in postreaction serum or a cross-reactive antibody to mouse antigens or both. More importantly, this case illustrates that rapid desensitization can be performed successfully without serious complications; therefore, systemic anaphylaxis can develop in susceptible atopic individuals receiving muromonab CD3 monoclonal antibody for renal graft rejection.

Adolescent↗
PubMed1990

Acute renal failure due to pyelonephritis.

Acute renal failure developed in a 3-year-old boy with acute pyelonephritis. Renal biopsy showed acute interstitial infiltration of neutrophils and macrophages. There were also glomerulitis and capillary tuft thrombosis. He required peritoneal dialysis, but subsequently recovered renal function. Prompt antimicrobial therapy is crucial to insure a favorable outcome. Pyelonephritis is an unusual cause of acute renal failure in infants and children.

Acute Disease↗
PubMed1989

Mesangiolytic glomerulopathy in a bone marrow allograft recipient.

A boy with null-cell leukemia received a bone marrow allograft after preparation with chemotherapy and total body irradiation. Cyclosporine A was not administered following transplantation. Renal biopsy performed 6 months after transplantation because of unexplained deterioration of renal function revealed diffuse mesangiolysis and glomerular sclerosis. The significance of this finding is discussed with reference to similar, recently reported cases.

Bone Marrow Transplantation↗
PubMed1988

Renal histopathology of the nail-patella syndrome in a two-year-old boy.

A two-year-old child with the clinical stigmata of nail-patella syndrome, congenital urinary tract anomalies and proteinuria underwent renal biopsy. Electron microscopy revealed characteristic electron lucent areas and collagen fibril-like deposits in the glomerular basement membrane. Of special interest, electron dense deposits were seen in subendothelial areas of the capillary loops and immunofluorescent staining was striking, particularly for IgM, in a peripheral capillary loop pattern.

Biopsy↗
PubMed1987

Galactosemic nephropathy in the rat.

The effect of 30% galactose feeding on kidney function and structure was compared to the effect of streptozotocin-induced diabetes in the rat. In the galactose-fed rats there was increased urine volume (500%), creatinine clearance (40%), urinary albumin excretion (100%), urinary N-acetyl glucosaminidase (600%) and relative kidney weight (21%). These changes were similar to that observed in streptozotocin-induced diabetic animals. Galactitol in the kidney cortex of galactose-fed rats was increased 4 times similar to that observed for sorbitol in the streptozotocin-induced diabetic animals. Glycosylated hemoglobins were also increased in both galactose-fed animals and streptozotocin-treated animals. These data suggest that galactose feeding may be a useful model for investigating some aspects of diabetic nephropathy.

Acetylglucosaminidase↗
PubMed1986

Three-dimensional studies of acellular glomerular basement membranes in dense-deposit disease.

After digestion removed the cells from glomeruli of frozen kidney tissue, we employed scanning electron microscopy to examine the acellular glomerular basement membranes (AGBM) from normal kidneys and from kidneys of patients with dense-deposit disease (DDD). The AGBM showed previously unrecognized three-dimensional patterns of pathologic changes. When compared to normal controls, the AGBM in DDD appeared "rigid" and thickened. Other pathologic features included coarsely granular or undulating epimembranous surfaces punctuated by single or clustered crater-like deformities. Although epimembranous crater-like deformities have been observed in other glomerulopathies, the combination of "rigid"-appearing AGBM punctuated by crater-like deformities is thus far unique to DDD.

Adolescent↗
PubMed1986

Vesicoureteral reflux, proteinuria and renal failure.

We report 3 cases of proteinuria, progressive renal insufficiency and vesicoureteral reflux with no history of urinary tract infection. Renal histology showed focal segmental glomerulosclerosis. These associations are unusual during childhood but they are common in adults. Generally, vesicoureteral reflux is discovered during radiological evaluation of children with recurrent urinary tract infections. Renal parenchymal damage in children typically results from recurrent infection or progressive hydronephrosis. Development of proteinuria with vesicoureteral reflux usually indicates an irreversible glomerular lesion. Antireflux surgery in patients with vesicoureteral reflux and decreased renal function may be beneficial if performed before the onset of proteinuria. We recommend antireflux surgery for children with persistent vesicoureteral reflux or decreased renal function.

Child↗
PubMed1986

Scanning electron microscopy of the acellular glomerular and tubular basement membrane in lupus nephritis.

After using a cellular digestion technic to extract cells from the basement membranes of frozen kidney tissue, we used scanning electron microscopy to examine the acellular glomerular basement membranes (AGBM) and acellular tubular basement membranes (ATBM) from normal kidneys and from the kidneys of patients with lupus nephritis. This method revealed, in the AGBM, previously unrecognized three-dimensional patterns of pathologic changes. These patterns correlated with the World Health Organization (WHO) subclass of lupus nephritis and with the quantity of immune-complex deposition seen with two-dimensional microscopy. These pathologic changes included epimembranous, crater-like deformities with and without material resembling immune complexes; severely distorted, "moth-eaten" glomerular basement membrane; and the formation of secondary basement membrane within glomerular capillaries. We did not see similar abnormalities in the ATBM.

Adolescent↗