Strategy to reduce the risk of positive pancreatic resection margin at pancreatico-duodenectomy.

Background: The accuracy of histological assessment of frozen section (FS) of the pancreatic resection margin (PRM) at pancreatico-duodenectomy can be improved by concurrent FS examination of a sample of the suspected pancreatic lesion.

Methods: A prospective trial was conducted using archived material. FS of all the PRM and suspected pancreatic lesion of 12 patients randomly selected from a historical group who underwent pancreatico-duodenectomy for suspected malignancy were examined by five histopathologists.

Expression of Ras GTPase isoforms in normal and diseased pancreas.

Background: Ki-Ras is well studied in its oncogenic form in relation to pancreatic pathologies. However, the individual contribution of each of the wild-type Ras isoforms (Ha-, Ki-, and N-) in pancreatic cells in health and disease is unknown.

Methods: Archival formalin-fixed, paraffin-embedded specimens of normal (n = 6) and malignant pancreas (n = 35) were used for immuno-histochemical detection of Ras isoforms using a modified polymer system.

Subcellular distribution of Ras GTPase isoforms in normal human kidney.

Background: Ras GTPase isoforms have been implicated in proliferative renal disease and are known to have differential cellular expression in kidney. However, their exact subcellular location in various cells is unknown.

Methods: Immunogold labelling for Ras isoforms (Harvey, Kirsten and Neural) was performed for subcellular localization under electron microscopy in fresh normal kidney specimens, obtained from the opposite pole of kidneys removed for renal cell cancer.

Expression of Ras GTPases in normal kidney and in glomerulonephritis.

Background: Small monomeric Ras GTPases play critical and specific roles in the control of cellular proliferation and apoptosis but the expression of the three Ras isoforms (Ha-Ras, Ki-Ras and N-Ras) in human renal tissue is unknown. This work is an immunohistochemical study of Ras expression in normal renal tissue and in membranous glomerulonephritis (MGN), IgA nephropathy (IgAN) and IgA-negative mesangioproliferative glomerulonephritis (MPGN).

Methods: Formalin-fixed, paraffin-embedded tissue was stained using pan-Ras monoclonal antibody (mAb) and Ras isoform-specific mAb.

Collecting duct carcinoma of the kidney associated with the sickle cell trait.

Collecting duct carcinoma of the kidney is a rare neoplasm that arises from the medullary collecting ducts. It has an aggressive clinical course and patients usually present with metastatic disease. Treatment approaches apart from surgery have been unrewarding.

Alterations in the glomerular charge barrier in human lupus nephritis.

Renal tissue taken from ten patients with proteinuria and diagnosed as suffering from human lupus nephritis was examined by a post-embedding charge labelling method using cationic gold (CG). The method allows localization of the anionic charge in the glomerular epithelial cell coat and/or glomerular basement membrane (GBM). Our results demonstrate that in human lupus nephritis there are gaps in the charge barrier associated with immune deposits found in the lamina rara externa of the GBM.

The effect of cyclosporin A on cationized bovine serum albumin-induced nephropathy in NZW rabbits.

The effect of cyclosporin A (CyA) was studied on the morphology and protein excretion of a rabbit chronic serum sickness nephritis using cationized bovine serum albumin (cBSA). One group of rabbits was given intravenous (i.v.

Immunoelectron microscopy of cationized bovine serum albumin-induced glomerulonephritis in the rabbit.

Chronic immune complex glomerulonephritis was induced in a group of New Zealand white rabbits by daily intravenous injections of cationized bovine serum albumin (cBSA). The animals were serially killed and renal tissue was embedded in the hydrophilic resin Lowicryl K4M for immunoelectron microscopy. The results demonstrate the progressive deposition of rabbit IgG in the glomerular basement membrane in this model, with aggregation of immunoglobulins occurring only in the subepithelial space.

Glomerular epithelial cell endocytosis of immune deposits in human lupus nephritis.

Sixteen human renal biopsies taken from patients suffering from systemic lupus erythematosus nephritis were examined using an immunohistochemical method which allows the localisation of IgG at both light and electron-microscopical levels. The tissue was embedded in the hydrophilic resin lowicryl K4M and sections were stained using gold-labelled antibodies. On routine light microscopical examination the biopsies were diagnosed as: 1 case of WHO type II, 3 type III, 9 type IV, 2 type V, and 1 type III/V.

Glomerular epithelial-cell endocytosis of horseradish peroxidase-polylysine conjugate in immune-complex glomerulonephritis.

Glomerulonephritis was induced in rats by daily intravenous cationised bovine serum albumin. The conjugate of horseradish peroxidase with poly-L-lysine was injected as a tracer of endocytosis by glomerular epithelial cells. The rats were sacrificed serially from 1 min to 24 h after the injection of the conjugate.

Light and electron microscopic demonstration of extracellular immunoglobulin deposition in renal tissue.

Extracellular immunoglobulin (IgG) deposits were shown by both light and electron microscopy in renal biopsy material using immunogold labelling. After fixation of tissue in 4% paraformaldehyde and embedding in Lowicryl K4M, semithin sections were cut and stained using the immunogold silver stain. The sections were then viewed and areas of interest were noted; ultrathin sections were cut from the same block of tissue, then stained using immunogold.