Post-streptococcal glomerulonephritis: studies on the interaction between nephritis strain-associated protein (NSAP), complement and the glomerulus.

Nephritis strain-associated protein (NSAP), a streptokinase produced by strains of streptococci isolated from patients with acute glomerulonephritis, is believed to be a specific antigen which participates in the production of glomerular injury. In order to investigate the mechanisms by which NSAP induces damage we have examined its potential to activate complement in vitro and to bind to isolated human glomeruli. NSAP, both alone and in combination with specific antibody, caused depletion of complement in normal human serum as measured by total haemolytic complement activity and generation of the complement breakdown products. C3a and C4a. Furthermore, Scatchard analysis showed that NSAP bound tightly to human glomeruli (Ka of 400 +/- 240 x 10(6) M) when compared to non-nephritic streptokinase (Ka of 7.3 +/- 4.1 x 10(6) M) and fully cationized human serum albumin (Ka of 0.6 +/- 0.04 x 10(6) M). These findings are consistent with the hypothesis that the deposition of streptococcal antigens within the glomerulus may precede the fixation of complement and specific antibody.

Microcomputer database and system of audit for the vascular surgeon.

We have set up a vascular database based upon an IBM personal computer in the vascular unit at Repatriation General Hospital, Concord, using 'Dataease'. This is commercially available software that allows the development of a database by users with little or no programming knowledge. The database is menu driven and designed to record details of admissions, indications for surgery, operations, complications and follow-up and has been set up as a prospective project from 1 January 1989 after a pilot study in 1988. Currently, interns, residents and registrars enter data directly onto the computer, providing an excellent teaching and review medium. Unit audit is easy as the program is completely menu driven and there are more than 100 customized reports written, ranging from providing simple complication details to complex reports deriving graft cumulative patency rates. This system also provides for 'instant' discharge letters which have markedly improved communication with the general practitioner.

A new method for reduction of endotoxin contamination from protein solutions.

A method of reducing endotoxin contamination in protein-containing solutions is described here using a combination of polymyxin B-Sepharose 4B (PB-Seph 4B) affinity binding and endotoxin-protein dissociation with the dialyzable surfactant, octyl-beta-D-glucopyranoside (OBDG). Using the limulus amoebocyte lysate (LAL) assay to detect endotoxin, greater than 1000-fold reduction of endotoxin reactivity could be accomplished from a contaminated commercial preparation of bovine catalase. Importantly, this occurred with only a 24% protein loss and an 11% loss of catalase enzymatic activity after treatment. The treated catalase appeared to be largely endotoxin-free since it no longer elicited a pyrogenic response in rabbits or primed for intravascular coagulation of the generalized Shwartzman reaction. Of interest, OBDG treatment of Salmonella minnesota Re595 lipopolysaccharide enhanced its ability to bind to serum high density lipoproteins which might contribute to decreased in vivo toxicity. In quantitative studies using radiolabeled endotoxin, the OBDG was shown to be capable of dissociating protein-bound endotoxin thereby facilitating its binding to the PB-Seph 4B adduct. The technique was also useful in removing radiolabeled endotoxin added to human IgG. The methodology described here would be expected to have general usefulness in reducing endotoxin contamination of macromolecular solutions that can bind and retain endotoxin.

Surgical management of primary aldosteronism (Conn's syndrome), a correctable cause of hypertension.

Clinical, operative and pathological findings in a series of 18 patients with aldosterone producing adrenal cortical adenomas are reviewed. All patients presented with hypertension and hypokalaemia. The main challenges in preoperative diagnosis were to differentiate primary aldosteronism from other causes of hypokalaemia, such as diuretic therapy, to establish the presence of a discrete adenoma and to localize the tumour to the left or right adrenal gland. A high rate of success was achieved in predicting a surgical diagnosis of aldosterone-producing adenoma. This was attributed to thorough biochemical evaluation of the underlying metabolic state by measurement of renal potassium handling and by determining the responses of the renin-aldosterone axis to changes in sodium balance. Preoperative tumour localization, using adrenal phlebography or scintiscanning, was accomplished in only eight cases. Our experience suggests that the transabdominal approach is preferable for cases in which a unilateral lesion is not clearly identified by imaging techniques.