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Biomedical subjects

W P Richardson

Publications and source records attributed to W P Richardson.

17 recordsLinked to original sources
PubMed1997

Renal structural-functional relationships in early diabetes mellitus.

To define the earliest renal morphological changes in patients with type I diabetes, we studied renal function and morphometric analysis of renal biopsies in 59 patients with diabetes for 5-12 years and normal blood pressure, normal creatinine clearance (CCr), and negative dipstick urinary protein. Arteriolar hyalinization and intimal fibrous thickening were noted in 43%. Glomerular basement membrane thickness and fractional mesangial volume were increased in 51% and 56%, respectively. The pre-pubertal and post-pubertal years of diabetes were associated with similar degrees of renal structural changes, but during the pre-pubertal years normal urinary albumin excretion (UAE) was seen. Principal factor analysis of morphometric structural parameters yielded four clusters of variables: "glomerular size" correlated with patient age, CCr, and UAE; "peripheral capillary decrease" correlated with glycosylated hemoglobin, diastolic blood pressure, glomerular filtration rate, and UAE; "mesangial increase" correlated with UAE; and "interstitial scarring" correlated with diastolic blood pressure. This study provides unique documentation of renal structural abnormalities which precede clinically evident renal functional abnormalities and documents that these early structural abnormalities are present in the pre-pubertal years of diabetes as well as postpuberty, and are associated with each other in constellations that correspond to postulated mechanisms in diabetic nephropathy.

Adolescent↗
PubMed1994

Bilateral penetrating keratoplasty for sclerocornea in an infant with monosomy 21. Case report and review of the literature.

An 8-month-old caucasian girl with monosomy 21 and sclerocornea underwent bilateral penetrating keratoplasties. Both light and electron microscopic studies were performed on the corneal buttons. Light microscopy revealed variable and abnormal corneal thickness with the peripheral cornea being thinner than the center, lack of Bowman's layer, irregular stromal lamellae, stromal vascularization, markedly underdeveloped or absent Descemet's membrane, and marked attenuation of the endothelium. Electron microscopy demonstrated basal epithelial cells with a thin epithelial basement membrane residing directly on stromal lamellae without intervening Bowman's layer. Stromal collagen fibrils were irregular in size measuring 38-69 nm in diameter. We believe this to be the first report of corneal transplantation and the second reported case of sclerocornea in a patient with monosomy 21.

Chromosomes, Human, Pair 21↗
PubMed1989

Dietary protein and glomerular response to subtotal nephrectomy in the rat.

Renal tubules and glomeruli undergo hypertrophy after partial renal ablation. Glomerular and vascular scarring and progressive renal insufficiency may later occur. In the present studies, we have documented the filtration characteristics of glomeruli isolated from rats that had undergone subtotal nephrectomy and been fed a normal protein (NP) diet (24 gm protein per 100 gm chow) or a protein-restricted (PR) diet (6 gm protein per 100 gm chow) and compared these glomeruli to those of sham-operated (SHAM) rats maintained on a normal diet. Body weight of SHAM rats increased by 30% during the 28 weeks of the study. Weight of NP rats did not change significantly, and weight of PR rats decreased by about 25%. Seven weeks after surgery, the glomeruli of NP rats were significantly larger and the ultrafiltration coefficients (Kf) were higher than those of SHAM rats; glomeruli of PR rats were of normal size but also had increased Kf. Twenty-eight weeks after surgery, the glomeruli of rats in each group were larger than at 7 weeks. Kf was no longer elevated in NP rats. Glomerular capillary hydraulic conductivity (Lp) was equal in all groups at 8 days but was increased at 7 weeks and decreased 28 weeks after surgery in NP rats. We hypothesize that glomerular hypertrophy occurs in response to renal ablation and that subsequent changes in the capillary wall lead to diminished Lp. Protein restriction in this model prevents both glomerular hypertrophy and a decrease in Lp.

Animals↗
PubMed1988

Ultrafiltration coefficients of glomeruli from human biopsies.

Ultrafiltration coefficient (Kf) was measured in vitro using glomeruli isolated from 28 human renal biopsies in order to asses both the relationship between glomerular structure and filtration characteristics and the relationship between Kf and patients' clinical state. The patients, ages 1 to 72 years, had a wide variety of renal diseases and serum creatinines of 1 to 16 mg/dl. Glomeruli were examined by light, immunofluorescence and electron microscopy, and glomerular alterations were measured. Filtration was induced in isolated glomeruli by an oncotic gradient and Kf calculated. Glomerular diameter (D), averaged for each patient, varied from 131 to 315 microns, and Kf varied from 5.7 to 51 nl/min mm Hg. Hydraulic conductivity (Lp) in 15 biopsies averaged 1.45 mu.min-1.mm Hg-1.cm-2. In order to identify the significant predictors of Kf and delineate their relationships, stepwise multiple regression analysis was performed. Kf increased with increasing glomerular size and with increasing degree of glomerular hypercellularity. D, in turn, increased with body surface area, urinary protein, and degree of capillary damage, and decreased with percent senescent glomeruli and degree of epithelial foot process broadening. Kf did not significantly correlate with clinical measures of renal function.

Biopsy↗
PubMed1988

Induced engulfment of Neisseria gonorrhoeae by tissue culture cells.

Engulfment of gonococci by mammalian tissue culture cells was examined as a model of the penetration of host cells in gonorrhea. Engulfment required viable organisms; killing the gonococci with heat or refrigeration abolished the process. Engulfment also required tissue culture cell microtubule- and microfilament-dependent movement; treating the cells with cytochalasin B (0.5 micrograms/ml) or demecolcine (Colcemid; Ciba-Geigy AG, Basel, Switzerland) (10 micrograms/ml) also prevented his process.

Animals↗
PubMed1985

Endothelial and epithelial-like cell formations in a case of posterior polymorphous dystrophy.

Histology of the endothelial and epithelial-like cells, vesicles, and membranes seen on the posterior corneal surface in posterior polymorphous dystrophy were examined by light microscopy and scanning and transmission electron microscopy in a 3-month-old female infant. The entire posterior surface of both corneas was covered by a geographic pattern of endothelial and epithelial-like cells, sometimes creating vesicles and sometimes creating partially detached sheets of cells. The thickness of Descemet's membrane varied widely, showing a tendency to be most complete under the remaining endothelial cells and thinner or absent under the epithelial-like cells. Details of this histology have important implications for our understanding of congenital diseases of corneal endothelium.

Cornea↗
PubMed1985

Ultrafiltration coefficient of isolated glomeruli of rats aged 4 days to maturation.

In the developing rat, RBF and GFR increase in parallel. We have calculated filtration coefficient (Kf) and hydraulic conductivity (Lp) of the glomerular capillary using glomeruli isolated from Munich-Wistar rats aged 4 days to adult. Lp derived as the quotient of Kf and total basement membrane area (LpS) may represent a minimum estimate, while the quotient of Kf and the peripheral basement membrane area (LpP) may more accurately represent the value that is operative in vivo. Rats in Group 1 (age 4 to 9 days) had an average glomerular diameter of 87 +/- 3 microns, Kf of 1.7 +/- 0.3 nl/min . mm Hg and LpS and LpP, 1.9 +/- 0.2 and 4.4 +/- 0.6 microliter/min . mm Hg . cm2, respectively. Glomerular diameter and Kf were not significantly increased in rats of Group 2 (22 to 36 days), but LpS and LpP diminished to 1.5 +/- 0.1 and 2.6 +/- 0.2 microliter/min . mm Hg . cm2 because of an increase in basement membrane surface density. In older rats of Groups 3 (69 to 84 days) and 4 (about 120 days, wt 205 +/- 4 g), glomerular diameter and Kf increased progressively. Kf and diameter were greater in deep than in superficial glomeruli of Group 4. In superficial glomeruli of Group 4, LpS averaged 1.1 +/- 0.1 and LpP 2.0 +/- 0.1 microliter/min . mm Hg . cm2, and were significantly lower than the values for Group 2 but not different from those of deep glomeruli of Group 4. Relative erythrocyte ejection increased with increasing glomerular diameter, indicating decreasing capillary resistance. Our observations at consistent with the previous reports that renal perfusion, Kf, and filtration rate increase in parallel, but do not support the hypothesis that glomerular capillary hydraulic conductivity increases as the filtration barrier matures.

Age Factors↗
PubMed1981

Glomerulopathy associated with cytomegalovirus viremia in renal allografts.

We investigated the relation between cytomegalovirus (CMV) infection and renal-allograft dysfunction in 14 patients. In seven instances (including two successive transplants in one patient), allograft dysfunction occurred during clinically manifest, viremic CMV infection. In five of these, biopsies revealed little or no tubulointerstitial change but a distinctive, diffuse glomerulopathy characterized by enlargement or necrosis of endothelial cells and accumulation of mononuclear cells and fibrillar material in glomerular capillaries. Two of these allografts recovered their function, both with cessation of high-dose immunosuppression. Biopsies in the other 10 patients revealed predominantly tubulointerstitial changes typical of cellular rejection, and most of these patients did not have viremia. One additional patient, studied prospectively, manifested both forms of allograft injury: tubulointerstitial changes occurring two weeks after transplantation and responding to increased immunosuppression, and CMV-associated glomerulopathy occurring seven weeks after transplantation and responding to decreased immunosuppression. We conclude that viremic CMV infection can cause acute glomerular injury and that recovery may be favored by a decreased in immunosuppressants.

Cytomegalovirus Infections↗
PubMed1977

Production of a capsule of Neisseria gonorrhoeae.

Neisseria gonorrhoeae can be induced to form a large capsule that can be visualized with India ink. Encapsulated gonococci appeared to be resistant to non-antibody-mediated phagocytosis compared with unencapsulated gonococci of the same strain and colony type.

Neisseria gonorrhoeae↗
PubMedDate not supplied

Multicentric bilateral renal cell carcinomas and a vascular leiomyoma in a child.

We report a unique case of multicentric bilateral renal cell carcinomas and a simultaneous large renal vascular leiomyoma in an 11-year-old child with sickle cell anemia. The patient presented with several episodes of massive hematuria. Abdominal sonography and computed tomography demonstrated bilateral renal neoplasms and the patient was clinically thought to have bilateral Wilms' tumor. An initial biopsy of the lower pole of right kidney revealed a renal cell carcinoma. Accordingly, bilateral renal angiography followed by right total nephrectomy and left upper pole partial nephrectomy were performed. Pathologic studies showed multicentric, bilateral renal cell carcinomas (two in the right kidney and one in the left kidney), of clear, granular, and oncocytic cell types. A simultaneous large vascular leiomyoma was also present in the right kidney. The smooth muscle nature of the leiomyoma was determined by light microscopy, immunohistology, and electron microscopy. The diagnostic difficulties in distinguishing them from other renal tumors are discussed.

Anemia, Sickle Cell↗