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Biomedical subjects

W R Griswold

Publications and source records attributed to W R Griswold.

At least 37 records · Page 2Linked to original sources
PubMed1988

Follow-up of infants with bilateral renal disease detected in utero. Growth and renal function.

We studied 69 infants who had urinary tract abnormalities detected by antenatal ultrasound examination. There were 21 intrauterine or immediate neonatal deaths; in all 21 infants, severe bilateral renal disease incompatible with life was found at autopsy. Six of the live-born infants with abnormal results of antenatal ultrasound examinations had a normal urinary tract after birth. Of the remaining 42 infants, the prenatal diagnosis was confirmed with renal ultrasound and other studies during the first week of life. Twenty-one of 42 infants had bilateral renal disease. We obtained follow-up data on 19 of 21 of these infants. Twelve of 19 had obstructive uropathy that was treated surgically. After one to 51 (mean, 18) months of follow-up, renal function varied. Ten of 19 patients had a calculated glomerular filtration rate greater than or equal to 79 mL/min/1.73 m2. One infant required long-term ambulatory peritoneal dialysis. Renal function (glomerular filtration rate, 74 +/- 5 mL/min/1.73 m2) and growth (height percentile, 41 +/- 8) were unexpectedly good considering the severity of the urinary tract abnormalities. Prenatal detection of bilateral renal disease followed by careful medical and surgical management results in a favorable outcome with good growth and renal function.

Adolescent↗
PubMed1987

Theoretical analysis of the sensitivity of the solid phase antibody assay (ELISA).

The sensitivity of the solid phase ELISA antibody assay was analyzed from a theoretical perspective. Results show that the investigator may choose either affinity dependent or affinity independent performance by adjusting the assay conditions. High antigen concentration (concn) and small interepitope distance favor affinity independence, while low antigen concn and large interepitope distance favor affinity dependent assay behavior. The maximum sensitivity will occur in the affinity independent region. Antibody titers obtained under affinity independent conditions will reflect true antibody concn, but measurements performed under affinity dependent conditions will underestimate antibody concn.

Antibody Affinity↗
PubMed1987

Theoretical analysis of the reaction of multivalent antigen with heterogeneous antibody: a model of soluble phase antibody assays.

The theoretical characteristics of soluble phase antibody assays were analyzed using a computer model of antigen-antibody interaction which allowed antibody to be heterogeneous and antigen multivalent. Studies show that when antibody is heterogeneous with respect to affinity, the high affinity antibody will usually mask the low affinity antibody. If the reaction of multivalent antigen with multispecific antibody is studied in antigen excess, the reaction closely approximates a one to one binding reaction. Several characteristics of the soluble phase antibody assay are determined by the affinity-antigen product or the product of the antibody affinity constant multiplied by the molar antigen concentration. When the product is high, the sensitivity of the assay will vary with antigen concentration and titers will be independent of antibody affinity. If the affinity-antigen product is low, sensitivity is dependent upon antibody affinity and titers will reflect antibody affinity as well as antibody concentration.

Antibodies↗
PubMed1987

Theoretical aspects of screening for high affinity monoclonal antibody to cell surface antigens.

The relative affinity of the cell-antibody interaction can be determined by finding the highest titer of one reactant which binds effectively to a fixed, dilute concentration of the other. There are two ways to perform these experiments: the antibody dilution method and the cell dilution method. The antibody dilution approach requires measuring the highest antibody dilution which can react with a small, fixed concentration of cells. If the endpoint antibody concentration is small, the antibody has a high binding constant. In the cell dilution method the investigator must find the highest cell dilution which can bind a small, fixed antibody concentration. If the antibody has a high affinity constant, the endpoint cell concentration will be small. When the antibody and cell receptor concentrations are known, functional binding constants can be calculated directly from binding data using equations presented in this paper. Binding constants measured by these methods will help predict the behavior of monoclonal antibodies in immunoassays and in experiments where monoclonal antibody is injected in vivo for imaging or pharmacologic delivery.

Antibodies, Monoclonal↗
PubMed1987

Treatment of childhood prednisone-resistant nephrotic syndrome and focal segmental glomerulosclerosis with intravenous methylprednisolone and oral alkylating agents.

Patients with prednisone-resistant nephrotic syndrome and biopsy-proven focal segmental glomerulosclerosis were treated with intravenous methylprednisone. After the first 2 weeks of therapy, the average urine protein excretion decreased from 247 to 96 mg/m2/h (p less than 0.04). Two of the 7 patients have had long-term, nearly complete remissions. The other patients relapsed. One relapsing patient was retreated with methylprednisolone and is now in remission. Four relapsing patients were treated with alkylating agents, in combination with methylprednisolone. All of these patients entered complete or partial remissions. Methylprednisolone causes a significant decrease in the proteinuria of children with focal segmental glomerulosclerosis. In addition, although the follow-up period is relatively short, it would appear that methylprednisolone, often in conjunction with an alkylating agent, has significantly improved the clinical status of these patients.

Administration, Oral↗
PubMed1987

A quantitative relationship between antibody affinity and antibody avidity.

The relationship between antibody avidity, measured by the dissociation of the antigen-antibody bond in antigen excess, and antibody affinity was studied. Complexes of radiolabelled antigen and antibody of known affinity were prepared in vitro and allowed to stand for seven days to reach equilibrium. Then nonlabelled antigen in one hundred fold excess was added to dissociate the complexes. After an appropriate incubation the fraction of antigen bound to antibody was measured by the ammonium sulfate precipitation method. The dissociation index was the fraction bound in the experimental sample divided by the fraction bound in the control. The correlation coefficient between the dissociation index and the antibody binding constant was 0.92 for early dissociation and 0.98 for late dissociation. The regression equation relating the binding constant to the dissociation index was K = 6.4(DI) + 6.25, where DI is the late dissociation index and K is the logarithm to the base 10 of the binding constant. There is a high correlation between avidity and affinity of antibody. Antibody affinity can be estimated from avidity data. The stability of antigen-antibody complexes can be predicted from antibody affinity.

Animals↗
PubMed1986

Microcomputer simulation of antigen-antibody binding at a fixed antigen/antibody ratio.

Computer simulation techniques were used to define the theoretical nature of the reaction of antigen with antibody at a constant degree of antigen excess. The simulation studies show that binding curves obtained under these conditions have unique features which are determined by antibody affinity, affinity heterogeneity and the concentrations of antigen and antibody. When analyzed by non-linear least squares regression these curves can be used to determine the affinity of antibody in homogeneous and heterogeneous systems.

Antibody Affinity↗
PubMed1986

Computer modeling of the reaction between antigen and heterogeneous antibody in fixed antigen excess: a new method for measuring antibody affinity.

Antigen-antibody binding experiments were performed by choosing antigen excess starting conditions and then diluting both the 125I-BSA antigen and anti-BSA proportionately so that the ratio between the reactants remained constant. The fraction antigen bound was measured at each dilution. Binding data were analyzed by computer using non-linear least squares regression to determine the affinity and affinity distribution of different antisera. Early anti-BSA was found to have a unimodal distribution with a binding constant in the range of 10(6)M-1. Intermediate anti-BSA had a bimodal distribution: 1/3 high affinity (1.0 X 10(9] and 2/3 low affinity (3.4 X 10(6)M-1). Late and hyperimmune rabbit BSA antibodies had unimodal affinity distributions with binding constants varying between 1.7 and 2.9 X 10(10)M-1. Antibody affinity can be readily determined by computer analysis of binding curves obtained in constant antigen excess conditions.

Animals↗
PubMed1985

Glomerulonephritis with absent glomerular basement membrane antigens.

This is a report of a child with glomerulonephritis and no family history of renal disease. On renal biopsy there was splitting and thinning of glomerular basement membrane antigens. These findings are similar to those seen in patients with familial nephritis and may be part of a spectrum of primary glomerular basement membrane defects.

Antigens↗
PubMed1985

Detection and measurement of multivalent antigen in the presence of low affinity antigen-antibody complexes.

Multivalent antigen which is bound to antibody can be difficult to measure and detect. There are 2 reasons for this phenomenon: (a) The antibody can mask the antigen so that it cannot react with antibody in the in vitro test system and (b) Complexes of multivalent antigen and antibody can precipitate spontaneously. In this study solutions to these problems were developed for the special case in which the antigen-antibody bond is of low affinity. The masking effect of low affinity antibody could be overcome by using a very high affinity antibody (K = 10(10) M-1) in the test system. The precipitation problem could be minimized by using fresh or thawed fresh frozen serum. In cases where antigen detection, rather than quantitation, is required, analysis of precipitates may be preferable because antigen is often selectively concentrated in the redissolved precipitates over serum values.

Animals↗
PubMed1984

A rapid method for the determination of antibody affinity.

A rapid method for estimating antibody affinity is described. To perform the assay fixed amounts of radiolabeled antigen and antibody are mixed in different total reaction volumes. The fraction of antigen bound to antibody is measured in aliquots from each reaction volume by the ammonium sulfate precipitation technique. Affinity constants can be estimated from these data graphically or by means of a microcomputer. This method is much quicker and easier to perform than traditional techniques for estimating antibody affinity.

Animals↗
PubMed1984

Theoretical analysis of the Farr antibody assay with a computer model: importance of antigen concentration and antibody affinity.

The Farr assay for antibody was analyzed theoretically in order to determine the maximum sensitivity of the assay, the quantitative relationship between actual antibody concentration and antibody estimates by the Farr technique, and the relationship between antibody affinity and the Farr avidity index. Analysis shows that sensitivity is limited by the antigen concentration when large amounts of antigen are used in the assay. Sensitivity at low antigen concentrations is maximal and varies with the affinity of the antibody studied. Antibody titers obtained by the Farr technique using low antigen concentrations vary with antibody affinity as well as antibody concentration. Titers measured at high antigen concentration are less affected by affinity and correlate better with antibody concentration. Antibody measurements expressed as Antigen Binding Capacity reflect antibody concentration only when the antigen concentration used in the assay exceeds a value equal to ten times the reciprocal of the antibody affinity constant. The Farr avidity index correlates with antibody affinity over a narrow affinity range. Different ranges of affinity can be examined by changing the antigen concentrations.

Antibodies↗
PubMed1984

Antibody affinity and acute immune complex disease.

The affinity of anti-BSA antibody was measured daily in rabbits with acute immune complex disease. Affinity values increased with time (r = 0.87: p less than 0.01). Antibody affinity before antigen elimination was 5.3 +/- 0.7 X 10(5)M-1 (Mean +/- SEM, n = 19); affinity after antigen elimination was 9.6 +/- 1.4 X 10(5)M-1 (n = 7). (p less than 0.01: Student's t-test). At the time serum creatinine was elevated antibody affinity was low averaging 7.6 +/- 1.24 X 10(5)M-1 (n = 9). These findings support the hypothesis that complexes of low affinity antibody and antigen may participate in acute immune complex injury.

Animals↗