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Biomedical subjects

D M Lynch

Publications and source records attributed to D M Lynch.

At least 37 records · Page 2Linked to original sources
PubMed1987

Antibody binding specificity to donor sperm in sera from infertile patients.

Indirect testing for elevated sera levels of antisperm antibody assumes that all relevant antigens are present on the target sperm utilized. In the present study, the heterogeneity of reactivity of positive sera with sperm from different donors was addressed. When 68 sera that previously tested positive by either sperm immobilization test (SIT) or ELISA or both were tested for antisperm antibody levels by a quantitative ELISA using nine different sperm donors, the frequency of positive reactions was 51% for men and 81% for women. A 50% correlation of SIT- and ELISA-positive results could be improved to 85% using the same sperm specimen. This would improve the overall correlation of functional and ELISA test results from 95% to 99% in the infertile population studied. The data suggest that individual sperm may vary in their antigenic expression and that comparison of methods between laboratories could be improved if equivalent target sperm were used.

Antibodies↗
PubMed1987

Platelet antibody binding in systemic lupus erythematosus.

Using a combination of enzyme-linked immunosorbent assay and SDS-PAGE with protein blot (Western blotting), increased levels of serum platelet bindable immunoglobulin (SPBIg) were demonstrated in 10 of 10 thrombocytopenic patients with systemic lupus erythematosus (SLE) (7.0-60 fg Ig/platelet) with consistent binding to SDS-PAGE platelet fractions of approximate molecular weight (120 and 80 kDa). This pattern of Ig binding was characteristic of SLE and was not seen in 20 normal volunteers and infrequently seen in 20 patients with idiopathic thrombocytopenic purpura.

Autoantibodies↗
PubMed1986

A comparison of sperm agglutination and immobilization assays with a quantitative ELISA for anti-sperm antibody in serum.

An enzyme-linked immunosorbent assay (ELISA) that quantitates antisperm antibody in serum was compared with standard sperm agglutination and immobilization assays with the use of sera from 40 normal and 292 subfertile individuals. Quantitation of the assay was accomplished by standardizing assay parameters, including the incorporation of a standard reference curve, the number of whole target sperm, the optimal dilution of serum, the selection of microtiter plate, and the time and temperatures involved in the adsorption and incubation phases. With this method, the level of antisperm antibody binding to target sperm in 40 normal fertile individuals was found to be 2.3 (+/- 1.1 standard deviation [SD]) fg immunoglobulin (Ig)/sperm. An increased mean level of 7.4 +/- 3.7 fg Ig/sperm was determined in 84 infertile patients with positive agglutination and/or immobilization tests. In 208 individuals with negative agglutination and immobilization tests the mean concentration of antisperm antibody was 2.5 +/- 1.3 fg Ig/sperm. Postvasectomy patients assayed by this method had a mean Ig binding value of 7.1 +/- 2.4 fg Ig/sperm. The infertile group with positive agglutination and/or immobilization tests had a significantly higher mean antisperm antibody level than the normal fertile group, according to the Student's t-test for independent samples (P less than 0.001). This indirect serum-based assay reproducibly quantitates antisperm antibody binding to whole target sperm, suggests the normal and abnormal levels of antisperm antibody, and correlates with standard functional assays.

Antibodies↗
PubMed1986

Antigenic determinants in idiopathic thrombocytopenic purpura.

Serum platelet bindable immunoglobulin (SPBIg) was determined in a group of 23 idiopathic thrombocytopenic purpura (ITP) patients and compared to 20 normal, healthy controls. The mean SPBIg of the ITP group was 16.1 (+/- 17.9 SD) fg/platelet, while the normals were substantially lower, 4.0 (+/- 1.2) fg/platelet. Sera from patients of both groups were then incubated with platelet fractions immobilized on nitrocellulose membrane strips (Western Blotting) to detect platelet antigen specificity using a peroxidase labelled indicator antibody. The normal patient sera did not react with platelet fractions on the nitrocellulose strips. However, 21 of 23 ITP sera bound to one or more platelet fractions with large variations in the number and molecular weights of the platelet fractions identified by ITP antibody. These observations suggest the presence of multiple antigenic binding sites for platelet specific immunoglobulin in ITP sera. This variation may reflect heterogeneous antibodies binding to diverse antigens or homogeneous antibodies to a limited number of antigenic determinants shared by several discrete platelet molecules.

Autoantibodies↗
PubMed1986

Quantitation of sperm bindable IgA and IgG in seminal fluid.

Seminal fluid and serum from 95 infertile males were assayed for sperm bindable immunoglobulins using an indirect ELISA with whole target sperm. The ELISA method was compared to seminal fluid and serum immobilization and agglutination assays (functional assays). In this infertile group, the ELISA assay was positive in 22% of seminal fluids (greater than 1.2 fg IgA/sperm and greater than 0.3 fg IgG/sperm). The seminal fluid antibodies were IgA and had an accompanying elevated IgG component in 78% of patients. There was a 96% correlation between negative seminal fluid functional assays and negative ELISA, and a 95% correlation between positive seminal fluid functional assays and positive ELISA. Positive serum sperm antibody tests were found in 71% of the infertile males with positive seminal fluid sperm antibodies, but 29% of the infertile males with strongly positive IgA seminal fluid sperm antibodies showed normal levels of serum sperm antibodies by either ELISA or functional assays. The ELISA method gives reproducible quantitation of sperm antibodies in seminal fluid and correlates well with accepted functional assays. Comparisons with serum sperm antibody assays suggests that seminal fluid sperm antibody analysis complements the serum analysis of sperm antibodies.

Adult↗
PubMed1985

A quantitative ELISA procedure for the measurement of membrane-bound platelet-associated IgG (PAIgG).

A quantitative ELISA assay for the measurement of in vivo bound platelet-associated IgG (PAIgG) using intact patient platelets is presented. The assay requires quantitation and standardization of the number of platelets bound to microtiter plate wells and an absorbance curve using quantitated IgG standards. Platelet-bound IgG was measured using an F(ab')2 peroxidase labeled anti-human IgG and o-phenylenediamine dihydrochloride (OPD) as the substrate. Using this assay, PAIgG for normal individuals was 2.8 +/- 1.6 fg/platelet (mean +/- 1 SD; n = 30). Increased levels were found in 28 of 30 patients with clinical autoimmune thrombocytopenia (ATP) with a range of 7.0-80 fg/platelet. Normal PAIgG levels were found in 26 of 30 patients with nonimmune thrombocytopenia. In the sample population studied, the PAIgG assay showed a sensitivity of 93%, specificity of 90%, a positive predictive value of 0.90, and a negative predictive value of 0.93. The procedure is highly reproducible (CV = 6.8%) and useful in evaluating patients with suspected immune mediated thrombocytopenia.

Blood Platelets↗
PubMed1985

Pipothiazine palmitate in the management of aggressive mentally handicapped patients.

The efficacy of intramuscular pipothiazine palmitate (PP) in the management of aggressive mentally handicapped patients was examined in a double-blind, placebo-controlled, cross-over study, in which 30 patients received each treatment for 13 weeks. A target symptom scale of aggressiveness (TSA) and a clinical global impression scale of efficacy were rated at monthly intervals, and an extra-pyramidal side-effects scale weekly. The patients showed marked improvement during treatment with PP, which was assessed as superior to placebo. Individual and total TSA scores were also reduced compared to placebo.

Adult↗
PubMed1985

An enzyme-linked immunosorbent assay for the evaluation of thrombocytopenia induced by heparin.

Five patients with heparin-associated thrombocytopenia (HAT) were evaluated by platelet aggregation and quantitation of immunoglobulin binding to intact target platelets in both the presence and absence of heparin. These patients developed thrombocytopenia (12,000 to 70,000 platelets/microliter) 7 to 15 days and embolic and hemorrhagic complications 9 to 15 days after the initiation of heparin therapy. Platelet aggregation after the addition of heparin was demonstrated in two of four HAT serum samples, whereas normal serum samples showed no significant platelet aggregation. The five HAT serum samples showed normal to elevated baseline serum platelet-bindable immunoglobulin (SPBIg) with a range of 4.3 to 11.4 fg/platelet (normal less than or equal to 1.0 to 6.5 fg/platelet). When HAT sera were incubated with target platelets and heparin (5 U/ml), the SPBIg increased to 8.5 to 37.5 fg/platelet, a mean increase of 148% in the presence of heparin. Normal and control serum samples (from 10 normal laboratory volunteers, nine patients without thrombocytopenia receiving heparin, nine patients with autoimmune thrombocytopenic purpura, and nine patients with nonimmune thrombocytopenia not receiving heparin) showed only a slight increase in SPBIg of 0 to 2.8 fg/platelet above baseline, a mean increase of 15% after heparin incubation with the serum samples. The measurement of SPBIg of washed platelets incubated with test serum samples in the presence and absence of heparin is potentially a specific and sensitive in vitro test for the diagnosis of HAT and may prove more sensitive than platelet aggregation studies with heparin.

Enzyme-Linked Immunosorbent Assay↗
PubMed1985

Heparin-associated thrombocytopenia: antibody binding specificity to platelet antigens.

Sera from four patients with heparin-associated thrombocytopenia (HAT) were evaluated by a quantitative enzyme-linked immunosorbent assay (ELISA) to detect heparin-dependent serum platelet-bindable immunoglobulin (S-PBIg) and by Western blotting and immunoprecipitation to investigate the specificity of the antibody binding. All HAT sera showed mildly increased S-PBIg (mean, 7.8 fg per platelet; normal, less than 6.0 fg per platelet) to intact target platelets in the ELISA, which was markedly increased in the presence of heparin (mean, 20.9 fg per platelet). This increase was 20-fold greater than normal control sera, which showed a mean differential increase of only 0.5 fg per platelet. Immunoglobulin binding specificity to platelet antigens was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of platelet lysate with transfer of the platelet fractions onto nitrocellulose strips (Western blotting) and subsequent immunoassay using HAT and normal sera. In the presence of heparin, the four HAT patients demonstrated increased binding of immunoglobulin to platelet antigens of apparent molecular weights of 180, 124, and 82 kd. Radiolabeled heparin when incubated with HAT sera, normal sera, or albumin blanks bound to platelet proteins of the same apparent molecular weights. These observations are consistent with current hypotheses suggesting that HAT antibody is directed to heparin-platelet complexes or, alternatively, that heparin induces conformational change of antigenic sites on the platelet membrane.

Antibodies↗
PubMed1984

Preoperative AT-III values and clinical postoperative thrombosis: a comparison of three antithrombin-III assays.

Three antithrombin-III assays (Sigma functional plasma, von Kaulla functional serum, and Calbiochem-Behring radial immunodiffusion) are compared using preoperative serum and plasma from 48 patients admitted for cardiovascular or other major vascular surgery. Medical records were reviewed for evidence of thrombotic complications. Eight patients (17%) in this selected population had clinical evidence of postoperative thrombotic complications. The sensitivity and specificity for each AT-III assay were calculated, and the positive and negative predictive values in this population were determined. Sigma's plasma AT-III had the highest positive predictive value (67%) and negative predictive value (100%). The functional serum and RID assays had significantly lower positive predictive values (23% and 38% respectively) and negative predictive values of 86%. Using the Two Sample t-Test to evaluate differences in AT-III values between the two patient groups, i.e., those who experienced thrombotic complications and those who did not, only the functional plasma AT-III method was statistically significant at a 95% confidence interval.

Antithrombin III↗
PubMed1979

Quantitative structure-activity relationships for biguanides, carbamimidates, and bisbiguanides as inhibitors of Streptococcus mutans No. 6715.

Thirty-seven compounds, including 17 biguanides, 6 carbamimidates, and 14 bisbiguanides, were evaluated for potential antiplaque activity by measuring their minimum inhibitory concentrations [MIC (M)] against Streptococcus mutans no. 6715. Linear regression analysis was conducted with the log 1/MIC (M) values and log P, pi, sigma, and MR. The best correlation for the biguanides (r2 = 0.92) was obtained with log P and (log P)2. When the biguanides were included with the carbamimidates, essentially the same correlation (r2 = 0.91) was obtained with log P and (log P)2. The best correlation for the bisbiguanides (r2 = 0.70) was also obtained with log P and (log P)2. Use of an indicator variable (I) for the bisgiguanides allowed all three groups to be included in one equation, which accounted for over 87% of the variance in the data for inhibition of bacterial growth. These results from the classical parabolic model were also compared with those from the recently developed bilinear model.

Biguanides↗
PubMed1975

Survival of functional pancreatic acinar tissue in circumfusion organ culture enhanced by chemically defined medium with hydrocortisone.

Pancreatic explants from perinatal or 1-week-old rat circumfusion organ cultured with an insulin-free variant of Trowell's Medium T8 survive functionally, as judged from tissue amylase content, for about 3 days. When hydrocortisone 21-sodium succinate, 1.0 mg/liter, is added to the chemically defined medium, high levels of anylase persist for longer periods. Explants from 7-day-old animals, circumfusion cultured with hydrocortisone-supplemented medium, maintain tissue amylase levels equal to or greater than those of uncultured control pancreas for at least 5 days of culture, and over this period they release amylase into culture medium at a stable rate. Methods for maintaining functional pancreatic acinar tissue in culture provide a new biological model for in vitro analysis of the early defects of potential chemical carcinogens on this target organ.

Amylases↗