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Biomedical subjects

N M Thomson

Publications and source records attributed to N M Thomson.

86 records · Page 5Linked to original sources
PubMed1977

Guinea-pig nephrotoxic nephritis II. Autologous phase: complement activation without detectable injury.

In the autologous phase of nephrotoxic induced by sheep antibody to glomerular basement membrane (GBM) in Dunkin-Hartley and C4 deficient strain guinea-pigs, less than 50% of animals developed proteinuria at the height of the autologous antibody response despite high anti-sheep immunolglobulin tetres and fixation of guinea-pig IgG and complement in the kidney. tonly two of thirty-sdven animals (5-4%) developed progressive. In a passive model of autologous phase injury using high titres rabbit antibody to sheep IgG, proteinuria failed to occur despite fixation of up to 95 microng rabbit antibody per kidney. Repeated injection of sheep nephrotoxic antibody (NTab) caused a persisting nephrotic syndrome but not the characteristic proliferative lesion of anti GBM diseases in other species.

Animals↗
PubMed1976

Defibrination with ancrod in nephrotoxic nephritis in rabbits.

Defibrination with ancrod in nephrotoxic nephritis in rabbits. In rabbits with nephrotoxic nephritis, defibrination with ancrod provided protection when administered during the autologous phase, after extensive glomerular fibrin deposition had occurred and crescents and renal failure were developing. When further glomerular fibrin deposition was prevented by defibrination, deposited fibrin was rapidly removed, indicating that glomerular fibrin-clearing mechanisms are retained in crescentic nephritis. Defibrination had no effect on the extent of glomerular C3 deposition or on the amount of proteinuria.

Ancrod↗
PubMed1976

Morphological and immunological evidence of coagulopathy in renal complications of pregnancy.

Renal biopsies in 14 patients with P.E.T. or eclampsia showed constant I.F. reactions for IgM and fibrin, with frequent reactions for C1q and C3. The glomeruli showed reversible mesangial proliferation and swelling, with characterictic E.M. deposits, and segmental lesions were present in seven patients. Similar I.F. reactions occurred in three other patients with clinical diagnoses of P.E.T. whose biopsies demonstrated coexistent glomerular disease. Serum complement studies showed a significant rise in C3 in the third trimester of normal pregnancies and a further significant elevation in C1q and C3 in the third trimester of a series of unselected P.E.T. patients. In contrast, four patients from the biopsy series with eclampsia or severe P.E.T. showed profound depression of serum C3 and C4, at the time of maximum clinical severity, which was shown to return to normal in two patients. The I.F. findings confirm those of Petrucco et al (6), and, with the other data, suggest that immune-complex deposition and activation of the classical complement pathway could interrect with intravascular coagulation to produce the glomerular lesions of P.E.T. and eclampsia.

Adolescent↗
PubMed1976

The role of C3 in the autologous phase of nephrotoxic nephritis.

The role of complement has been studied in the autologous phase of nephrotoxic nephritis (NTN) in rabbits. No reduction in glomerular fibrin deposition, crescent formation or protection from renal failure was observed in either the standard model of NTN when decomplementing doses of cobra venom factor (CVF) were given before the autologous phase or in a telescoped model when CVF was administered before the nephrotoxic antibody. In the latter situation glomerular fibrin deposition and crescent formation were found in the absence of detectable deposition of C3. However, substantial protection was observed when circulating polymorphonuclear leucocytes (PMN) were depleted by antipolymorph serum. These observations establish the existence of a system of allergic glomerular injury mediated by PMN but independent of C3. It is postulated that this system may account for the glomerular injury seen in patients with Goodpasture's syndrome in whom glomerular C3 deposition is not found.

Animals↗
PubMed1975

IgA-associated glomerulonephritis.

Mesangial IgA depostiiton was detected by routine fluorescent microscopy of 19 cases of glomerulonephritis. Twelve patients had a variable degree of diffuse mesangial proliferative glomerulonephritis. The heterogeneous histological findings in the other seven patients show that mesangial IgA deposition alone does not have diagnostic specificity. However, when interpretation of the mesangial IgA deposition is complemented by clinical and histological information, a group of patients with the characteristic combined features can be distinguished.

Adolescent↗
PubMed1975

Guinea-pig nephrotoxic nephritis. I. The role of complement and polymorphonuclear leucocytes and the effect of antibody subclass and fragments in the heterologous phase.

In guinea-pig nephrotoxic nephritis induced by a sheep antibody there was minimal glomerular capillary deposition of C3 and accumulation of polymorphonuclear leucocytes (PMN) in the heterologous phase. The C4-deficient strain developed the same injury as normal Duncan-Hartley animals. Complement depletion with cobra venom factor, polymorph depletion with nitrogen mustard or anti-PMN serum and treatment with antihistamines provided no protection. The relationship between the dose of nephrotoxic antibody and the proteinuria was similar for gamma1 and gamma2 subclasses and the F(ab')2 fragment of gamma1 antibody. However, the F(ab') and F(ab) antibody fragments, though fixing on the glomerular basement membrane, did not cause proteinuria. It is concluded that the development of proteinuria in this system: is largely independent of the complement-polymorph system; is due to the fixation of the F(ab')2 fragment of the antibody molecule; and does not depend on an intact Fc piece.

Animals↗
PubMed1975

A quantitative evaluation of anticoagulants in experimental nephrotoxic nephritis.

The protective effects of anticoagulants in nephrotoxic nephritis in rabbits have been studied, using various doses of heparin and defibrination with ancrod. Massive doses of heparin (2000 units/kg/day) were required before significant reduction in glomerular fibrin deposition, extracepillary cell proliferation and urea retention occurred. Doses of 300 and 1000 units/kg/day were insufficient to modify fibrin deposition and cell proliferation. Defibrination with ancrod provided protection, judged by histological and functional criteria, comparable to 2000 units of heparin/kg/day; but fibrin could still be demonstrated in the glomeruli of animals treated with 2000 units of heparin/kg/day, contrasting with the virtual absence of fibrin in animals given ancrod.

Ancrod↗
PubMed1975

The role of polymorphonuclear leucocytes in the autologous phase of nephrotoxic nephritis.

The role of polymorphonuclear leucocytes (PMN) in the autologous phase of nephrotoxic nephritis (NTN) in the rabbit has been investigated. Depletion of circulating PMN by nitrogen mustard protected renal function and immunofluorescent examination showed reduction in glomerular fibrin deposition. Depletion of circulating PMN using a highly specific goat anti-PMN serum (APS) provided similar protection of renal function, highly significant reduction in proteinuria and histological and immunofluorescent examination showed reduced glomerular PMN infiltration, extracapillary cell proliferation and virtual absence of fibrin deposition. Although protection by nitrogen mustard may have been partly due to immunosuppression, no reduction in antibody response was detected in the APS-treated rabbits. The results implicate the polymorph as the principal injurious agent in this model of NTN, responsible directly or indirectly for both proteinuria and glomerular fibrin deposition.

Animals↗
PubMed1974

Immunofluorescent studies in renal biopsies in pre-eclampsia.

Renal biopsies were performed on 11 patients considered clinically and histologically to have pre-eclampsia. Immunofluorescent studies with fluorescein-labelled anti-IgG, IgA, IgM, and IgE complement, albumin, fibrin, and fibrinogen were carried out on the tissue obtained. Significant correlation was obtained between the clinical severity of the disease and the density and pattern of IgM and IgG deposition. Complement was found in glomeruli in severe cases, while complement deposition in the walls of afferent and efferent arterioles was a constant finding. These findings support the concept that an immunological mechanism may be responsible for the renal lesions in pre-eclampsia. If immunity does play a part in the pathogenesis of pre-eclampsia, possible mechanisms include the involvement of histocompatibility antigens and cross-reactivity of fetal and maternal tissues. Renal fibrin deposition in pre-eclampsia may be secondary to an immune process, an occurrence well-described in other forms of glomerulonephritis in man and other species.

Biopsy↗
PubMedDate not supplied

Apoptosis and the expression of genes of the Bcl-2 family and TGF-beta1 in rat renal allografts transplanted after donor-specific blood transfusion.

UNLABELLED: Factors involved in "operational" tolerance in animal models induced by recipient pre-treatment with donor-specific blood transfusion (DSBT) need elucidation. This study examined apoptosis, expression of genes of the Bcl-2 family and of TGF-beta(1) in isografts, rejecting and tolerant allografts. METHODS: Adult inbred Dark Agouti (DA) kidneys were transplanted, with immediate nephrectomy of recipient kidneys, to (1) ALLO, inbred Albino Surgery (AS) rats; (2) DSBT ALLO, AS rats who received two DA blood transfusions under cover of cyclosporine prior to transplantation; or (3) ISO, DA rats. Grafts were retrieved on day 1, 3, or 5. Apoptosis was assessed by TUNEL. RNA was extracted and reverse transcribed to cDNA for quantification by real-time PCR, relative to the 18s housekeeping gene. RESULTS: Apoptosis was negligible in ISO while it increased in allograft groups from day 1. On day 5, apoptosis in ALLO (114.0 +/- 30.6), involved renal tubular cells and leukocytes compared to DSBT ALLO (9.7 +/- 4.0) and ISO (0.9 +/- 0.3) involving leukocytes only. On day 1, DSBT ALLO had higher expression of Bax than ALLO or ISO. On day 3, DSBT ALLO and ALLO had higher TGF-beta(1) mRNA than ISO. On day 5, Bcl-2 expression was significantly decreased (P < .001) in ALLO compared to DSBT ALLO and ISO. Bad and Bid were higher in DSBT ALLO than in ALLO. TGF-beta(1) was higher in DSBT ALLO compared to ISO. CONCLUSIONS: Decreased expression of anti-apoptotic Bcl-2 gene may be implicated in increased apoptosis in rejecting allograft while expression of pro-apoptotic genes may be involved in the establishment of operational tolerance.

Animals↗
PubMedDate not supplied

Transplantation of kidneys from living related donors. Comparison with cadaveric kidney transplantation.

In a series of 271 transplantations of renal allografts, performed over 10 years, the rates of graft survival, patient survival, and morbidity in the recipients of allografts from living related donors (47 allografts) have been compared with those in the recipients of cadaveric allografts (224 allografts). The one-year graft survival rates were 88% for allografts from living related donors (100%, if these were HLA-identical) and 55% for cadaveric allografts, while the patient survival rates were 97% and 87%, respectively, in the same period. Morbidity rates (expressed as the number of days spent in hospital) for recipients of allografts from living related donors were approximately 50% of those for recipients of cadaveric grafts. Complications in the living related donors were minimal, and acceptable. It is concluded that transplantation of allografts from living related donors has many advantages over transplantation of cadaveric kidneys, and is a valuable adjunct to a cadaveric renal transplantation programme. Greater use of living related kidney donors should be encouraged in Australia.

Adolescent↗