Observations of glomerular epithelial cell structure in patients with type I diabetes mellitus

Overt proteinuria is a hallmark of diabetic nephropathy while microalbuminuria is thought to be a predictor of later onset of diabetic nephropathy. Yet the mechanisms for abnormal urinary protein leak in diabetes have not been defined. We studied 28 patients with type I diabetes for 7 to 33 years. Creatinine clearance, urinary albumin excretion rate (UAE), and multiple blood pressures were obtained in each patient. A renal biopsy was performed in each patient and in 28 normal subjects. Quantitative stereology was used to determine foot process (FP) width, filtration slit length density (FSLV) and filtration slit length/glomerulus (FSLG). FP width was slightly wider than normal in diabetic patients with UAE less than 250 mg/24 hr while FP was significantly wider than both of these groups in diabetics with UAE greater than 250 mg/24 hr. FSLV and FSLG were similar in normals and diabetics with UAE less than 250 mg/24 hr but both were reduced in diabetics with UAE greater than 250 mg/24 hr. UAE correlated with FP width (P less than 0.05), FSLG (P less than 0.01) and most precisely and FSLV (P less than 0.001). Diabetics with microalbuminuria had values for all the structural parameters measured here not different from diabetics with UAE in the normal range. Perturbations of epithelial cell structure are present in diabetes mellitus especially in patients with nephropathy. The exact relationships between albuminuria and epithelial cell structure remains to be elucidated.     

The effects of phorbol esters with different biological activities on protein kinase C

The sapintoxins are a series of naturally occurring fluorescent phorbol esters with a range of selective biological activities (e.g. pro-inflammatory but non-tumour promoting). Their ability to activate protein kinase C (PKC) in vitro has been studied. Both tumour promoting and non-promoting phorbol derivatives activate the enzyme in vitro at low concentrations. 12-deoxyphorbol-13-phenylacetate-20 acetate (DOPPA) acts as a partial agonist in the activation of protein kinase C. Structurally distinct phorbol esters may therefore preferentially activate different forms of protein kinase C. α-sapinine, a biologically inactive compound, binds to protein kinase C without stimulating the enzyme and prevents subsequent activation by phorbol esters such as 12-O-tetradecanoyl phorbol-13-acetate (TPA).     

Restorative treatment need assessment by dentally and nondentally trained subjects

A study was carried out which compared how two groups of people, one with clinical dental experience and one without, assessed restorative dental treatment need. Using a visual analogue scale, a group of final year dental students ( n = 50) and nonclinical university students ( n = 50) assessed the extent to which they considered common dental imperfections, viz. spacing of the upper anterior teeth and discolouration of upper anterior teeth, warranted restorative correction. The group of dental students judged the necessity for treatment of discolouration to be more urgent than correction of spacing. The nondental group did not differentiate between the degrees of need. Data were non‐normal in distribution but the use of appropriate statistical tests showed the differences in mean assessments to be significant.     

Membrane proteins of the nerve growth cone and their developmental regulation

The membrane polypeptides of growth cone fragments ("growth cone particles," GCPs) isolated from fetal rat brain by subcellular fractionation have been analyzed in further detail. The major polypeptides of salt-washed GCP membranes detected by 1-dimensional gel electrophoresis (Ellis et al., 1985b) resolve in 2-dimensional gels as a spot of 52 kDa that comigrates with beta-tubulin and reacts with anti-beta-tubulin; a 46 kDa, pl 4.3, polypeptide (pp46) that has no equivalent in the soluble fraction and is identical to one of the GCP's major phosphoproteins (Katz et al., 1985) and to GAP43 (Willard et al., 1985); a spot of 42 kDa that comigrates with actin; and a species of 34 kDa (p34) without soluble equivalent. The prominent 38 kDa doublet identified in 1-dimensional gels is difficult to resolve in 2-dimensional gels. The major phosphoproteins pp80ac, pp46, and pp40 (Katz et al., 1985), as well as p34 partition into the oil phase of Triton X-114 extracts, suggesting that they are integral membrane proteins, at least in our experimental conditions. The properties of pp46 reported here are in conflict with the highly hydrophilic amino acid sequence predicted for GAP43/B50/F1 (Basi et al., 1987; Karns et al., 1987). Growth-cone and presynaptic membrane proteins are compared as follows. After eye injection of 35S-methionine, GCPs and synaptosomes are isolated from the target areas of optic nerve of fetal and adult rats, respectively. Polypeptides are separated by 1- and 2-dimensional gel electrophoresis and the radiolabeled species identified fluorographically. The comparison of labeled GCP and synaptosome polypeptides shows that all 5 major Coomassie blue-stained polypeptides of GCP membranes (52, 46, 42, 38, 34 kDa) are intensely labeled after eye injection. However, in synaptosomes, these polypeptides are weakly labeled if at all; instead, an intensely labeled polypeptide of 28 kDa, and several additional species not seen in GCPs, have appeared. Therefore, the major growth cone membrane proteins are developmentally regulated, and the rates of synthesis and transport into the axonal ending of neuronal polypeptides change dramatically at the time of synaptogenesis.     

Pediatric solid-organ transplant recipients carry chronic loads of Epstein-Barr virus exclusively in the immunoglobulin D-negative B-cell compartment

Solid-organ transplant recipients are at risk for development of lymphoproliferative diseases. The purpose of this study was to examine the distribution of Epstein-Barr virus (EBV) load in the peripheral blood of pediatric transplant recipients who had become chronic viral load carriers (>8 copies/10(5) lymphocytes for >2 months). A total of 19 patients with viral loads ranging from 20 to 5,000 viral genome copies/10(5) lymphocytes were studied. Ten patients had no previous diagnosis of posttransplant lymphoproliferative disease (PT-LPD), while nine had recovered from a diagnosed case of PT-LPD. No portion of the peripheral blood viral load was detected in the cell-free plasma fraction. Viral DNA was found in a population of cells characterized as CD19(hi) and immunoglobulin D negative, a phenotype that is consistent with the virus being carried exclusively in the memory B-cell compartment of the peripheral blood. There was no difference in the compartmentalization based upon either the level of the viral load or the past diagnosis of an episode of PT-LPD. These results have implications for the design of tests to detect EBV infection and for the interpretation and use of positive EBV PCR assays in the management of transplant recipients.