A new method for the simultaneous quantitation of platelet-bound immunoglobuin (IgG) and complement (C3) employing an enzyme-linked immunosorbent assay (ELISA) procedure.

An ELISA technique for the quantitation of platelet-bound IgG and C3 is described. This is an antiglobulin consumption assay using commercial horseradish peroxidase conjugated anti-IgG and anti-C3 antisera. The greater the amount of antiglobulin consumed by the reaction with platelets the less is available to bind to an immune adsorbent in the form of human serum-coated polystyrene balls. This test can be calibrated by adding known quantities of IgG of C3 to the specific enzyme-linked antibody and the unbound fraction of antiserum is quantitated by allowing it to react with a chromogenic substrate for the enzyme and measuring the intensity spectrophotometrically, thus establishing an inverse relationship with the amount of antigen. Platelets from normal donors and those with non-immunological thrombocytopenia gave values of 1.3--15.5 ng IgG/10(6) platelets and 0.22--0.96 ng C3/10(6) platelets which are in accordance with the normal ratio of these proteins in normal serum. Fifteen patients in whom immune destruction of platelets weas suspected had excess platelet-bound IgG ranging from 30 to 450 ng IgG/10(6) platelets. In none of these patients could excess platelet-bound C3 be demonstrated. Compared to the antiglobulin consumption test we have found this test to be superior both technically and in terms of sensitivity and reproducibility.

[Typhoid fever presenting as histiocytic medullary reticulosis: a case report]. / Tifoïedkoors wat presenteer soos histiositiese medullêre retikulose. 'n Gevalbespreking.

Because of a pancytopenia, moderately cellular bone marrow with hypoplastic erythropoiesis but with active granulo- and thrombopoiesis and a conspicuous increase in histiocytic cells, a patient was provisionally diagnosed as having histiocytic medullary reticulosis. However, Salmonella typhi was cultured from blood, urine and stool specimens. After 3 weeks the Widal reaction showed a titre of 1/320 for the H-antigen and 1/1,280 for the O-antigen. The patient was treated with chloramphenicol for 10 days and the fever, enlarged spleen and enlarged lymph nodes returned to normal.

Platelet-bound IgM in autoimmune thrombocytopenia.

Elevated levels of platelet-bound IgG (PA-IgG) are a feature of autoimmune thrombocytopenia (ATP), but it is well documented that this does not occur in all cases. This has led us to investigate the role of platelet-bound IgM (PA-IgM) in these patients using a quantitative enzyme-linked immunosorbent assay (ELISA). Forty-five determinations of PA-IgM and PA-IgG were done on 24 patients with ATP. Elevated levels of PA-IgM were found in 93.3% of the determinations, while PA-IgG was elevated in only 71.7%. In 64.4% of determinations, both were elevated. Elevated PA-IgM or PA-IgG alone occurred in 28.9% and 6.7% of determinations, respectively. These results show the hitherto unrecognized frequent involvement of PA-IgM in ATP and suggests that a complex interrelationship exists between the two immunoglobulin classes in ATP. Some of the possibilities that might explain this interrelationship are discussed.

Pyelonephritis: renal urokinase and sialidase (neuraminidase) activity in rats fed a standard laboratory diet.

Renal stone formation can be caused by many different and varied disturbances, some of which are poorly understood. The relationship between urinary infection and renal stone formation has not been completely clarified. It is argued that renal stones form primarily as a consequence of the hydrolysis of urea by the bacterial enzyme urease. However, no explanation is given for microorganisms that produce urease only occasionally or not at all. The question arises as to whether the infection-induced microorganisms might not be playing a double role in renal stone formation by not only producing urease, but also by affecting in vivo urokinase (UK) and sialidase (SA) activity. With this in mind, the effect of Escherichia coli on renal UK and SA activity has been studied in male rats with a normal diet. The renal UK (P = 0.208) and SA (P = 0.2135) activities did not differ significantly between the two kidneys of the same rat. In contrast, when drainage from one kidney of a rat was externally obstructed, the UK and SA activities differed significantly between kidneys (P < 0.015). An increase in UK (r = 0.6456, P < 0.0001) and SA (r = 0.7507, P < 0.0001) activity was observed over time in the obstructed kidney. Subcutaneous injections with E coli reduced the UK activity of the obstructed kidney significantly (p = 0.017). However, the SA activity remained the same (P = 0.3929).(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of cardiopulmonary bypass and autotransfusion on platelet count.

A pilot study was carried out to determine whether autotransfusion increased the platelet count. Although only a small series was involved significant increases were shown.

Evaluation of an enzyme-linked immunosorbent assay in the serodiagnosis of amoebic liver abscess.

An indirect enzyme-linked immunosorbent assay (ELISA) was evaluated for the detection of anti-amoebic IgG and IgM antibodies to assess its value in distinguishing past from current infection in invasive amoebiasis, particularly in amoebic liver abscess (ALA) patients. Using sera from 295 individuals, the ELISA was also compared with the amoebic gel diffusion (AGD) test. In 100 patients the IgG-ELISA at a single test dilution of 1/6,400 had a sensitivity of 99% for clinically diagnosed ALA. In these same patients the IgM-ELISA at a single dilution of 1/400, had a sensitivity of 64% and a specificity of 97.9%. No cross-reactions were observed in sera from patients with collagen vascular disease. In 121 patients without clinical invasive amoebiasis, 8 were AGD-positive and 12 were IgG-ELISA-positive, giving the latter assay a specificity of 91.7%. This is thought to be due to past infection with Entamoeba histolytica. In symptomless carriers of pathogenic zymodemes, 10/11 were seropositive by the IgG-ELISA and 11/11 by the AGD test. There was an excellent correlation between the IgG-ELISA and the AGD test (r = 0.99). The IgG-ELISA is a sensitive, specific, simple and rapid test. It has the clinical advantage that results are obtainable 2 1/2 hours after receipt of the specimen, compared with the 24-48 hours required for the AGD test. The prompt availability of IgG-ELISA results could prove advantageous for implementation of early therapy. The IgM-ELISA was not found to be sensitive enough to be used as an index of active amoebic infection.

Pyelonephritis: renal urokinase activity in rats on essential fatty acid diets.

This study was undertaken to assess whether additions of different oils to the diets of male rats would affect the renal urokinase (UK) activity of healthy and pyelonephritic kidneys. Four groups of fatty acid diets were studied: fat-free, coconut oil, fish oil and evening primrose oil (EPO). Pyelonephritis was obtained by unilateral extrarenal urinary obstruction and subcutaneous injection of Escherichia coli. The UK activity of the non-obstructed kidneys did not differ statistically between rats infected and not infected with bacteria (P > 0.056), except within the coconut oil group. A statistically decreased UK activity was obtained with bacteria injected animals on a coconut oil diet (P < 0.0001). This phenomenon, namely a decrease in UK activity, was also seen with pyelonephritic kidneys of rats on fat-free, coconut and fish oil diets (P < 0.0065). However, the UK activity of the obstructed kidneys with and without infection in the EPO group remained similar (P = 0.8477). These results suggest that the UK activity in infection-induced renal stones may be restored by EPO containing diets and may be of high relevance in the prevention and treatment of infection-induced renal stones. This revelation now needs to be more fully investigated.