Biomedical subjects

J R Wands

Publications and source records attributed to J R Wands.

240 records · Page 14Linked to original sources

PubMedDate not supplied

Human hepatoma-associated cell surface antigen: identification and characterization by means of monoclonal antibodies.

A library of murine monoclonal antibodies reactive with human hepatoma cells was generated following immunization of Balb/c mice with an intact cloned human hepatoma cell line, designated PLC/PRF/5-NR. We report the characterization of one such IgG2a antibody, designated anti-PLC1. This antibody specifically stains parental PLC/PRF/5 cell membranes and membranes of SK-Hep 1 and Mahlavu human hepatoma cells grown in culture, using indirect immunofluorescence and horseradish immunoperoxidase techniques. A similar pattern of membranous staining was observed in solid tumors derived from the three hepatoma cell lines which were injected subcutaneously into athymic nude rats and mice. Spontaneous capping on the cell surface was observed in 7 to 30% of the three human hepatocellular carcinoma cell types when incubated in suspension with monoclonal anti-PLC1 at 37 degrees C. Treatment of cells with trypsin or sustained growth in culture did not affect the intensity of membranous staining. Monoclonal anti-PLC1 appeared specific, and antibodies did not stain a variety of human carcinoma cell lines and primary tumors of nonhepatic origin, or several normal human and murine tissues. Purified 125I-labeled monoclonal anti-PLC1 bound specifically to the three hepatoma cell lines in culture. Specificity of the antigen-antibody reaction was demonstrated by competitive binding inhibition in experiments using unlabeled homologous antibody. Binding of 125I-anti-PLC1 was not inhibited by unlabeled monoclonal antibodies to HBsAg or to alpha-fetoprotein. Two hepatoma cell lines secrete a protein that specifically blocks binding of 125I-anti-PLC1 antibodies to cell surface antigenic determinants. This "hepatoma-associated" protein was subsequently purified by affinity chromatography from supernates derived from the three hepatoma cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

PubMedDate not supplied

Comparison between polyclonal and first and second generation monoclonal radioimmunoassays in the detection of hepatitis B surface antigen in patients with hepatocellular carcinoma.

Serum from 221 black patients with hepatocellular carcinoma was tested for HBsAg using a polyclonal radioimmunoassay, and first and second generation monoclonal radioimmunoassays designated M1-RIA and M2-RIA. These monoclonal radioimmunoassays have a lower limit of detection of about 55 and 15 pg of HBsAg-associated epitopes per ml of serum. Correlations were made with other hepatitis B virus serologic markers such as anti-HBc and anti-HBs, using polyclonal radioimmunoassays. We found 47.5% (105/221) of the patients were HBsAg positive by conventional polyclonal radioimmunoassay; all of these patients were also reactive by monoclonal radioimmunoassay. Of the 116 polyclonal radioimmunoassay-negative patients, 4 (3.4%) were reactive by M1-RIA. These four patients were all positive for anti-HBc and/or anti-HBs antibodies. There were 106 of 112 patients negative for HBsAg by polyclonal radioimmunoassay and M1-RIA available for testing by the M2-RIA; 11 (10.4%) were found to be positive only by this test. Thus, with the use of M1- and M2-RIAs, the number of hepatocellular carcinoma patients negative for HBsAg by polyclonal radioimmunoassay was reduced by 14% in this population. More importantly, of the 11 M2-RIA-positive patients, six demonstrated anti-HBc and/or anti-HBs antibodies whereas the remaining five had no serologic evidence of recent or past hepatitis B virus exposure. Finally, of the 21 patients in this series with no markers of hepatitis B virus infection using polyclonal radioimmunoassay and M1-RIA, five (24%) were reactive for HBsAg-associated epitopes by M2-RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

Aberrant expression of nitric oxide synthase III in Alzheimer's disease: relevance to cerebral vasculopathy and neurodegeneration.

Alzheimer's disease (AD) has heterogeneous pathology, in part due to the large subset of cases (AD+CVD) with superimposed vascular lesions that are sufficient in number and distribution to accelerate the clinical course of dementia. Brains with AD+CVD have lower densities of neurofibrillary tangles and A beta-amyloid diffuse plaques, and increased numbers of cerebral vessels exhibiting p53-associated apoptosis relative to brains with uncomplicated AD. AD and AD+CVD both exhibit altered expression of the nitric oxide synthase 3 (NOS-III) gene; however, in AD+CVD, reduced NOS-III expression in cerebral vessels is associated with an increased frequency of vascular lesions, vascular smooth muscle cell apoptosis, and A beta-amyloid plaques. In contrast, experimental and spontaneous focal acute and subacute cerebral infarcts are associated with increased NOS-III expression in perifocal neurons, glial cells, cerebrovascular smooth muscle and endothelial cells, and diffuse A beta-amyloid plaque formation. This suggests that ischemic injury and oxidative stress can precipitate NOS-III-mediated cell loss and neurodegeneration. A role for aging-associated impaired mitochondrial function as a contributing factor in AD and CVD is suggested by the reduced levels of mitochondrial protein observed in AD and AD+CVD cortical neurons and vascular smooth muscle and endothelial cells. The aggregate findings suggest that cell loss and neurodegeneration may be mediated by somewhat distinct but overlapping mechanisms in AD and AD+CVD.

Alzheimer Disease↗

PubMedDate not supplied

A conjugate of 5-fluorouridine-poly(L-lysine) and an antibody reactive with human colon carcinoma.

The ribose moiety of 5-fluorouridine (FUR) was oxidized with periodate and the product was bound through a poly(L-lysine) bridge to monoclonal antibodies, denoted SF25MAb, reactive with a human colon carcinoma LS180. The antibody was linked via its polysaccharide (previously oxidized with periodate) to the poly(L-lysine)-drug conjugate. The linking of FUR-poly(L-lysine) to the antibody markedly increased the latter's binding to the tumor cells. A relatively lower increase was also observed with conjugates of nonrelated antibodies, such as anti-hepatitis B surface antigen and anti-epidermal growth factor receptor antibodies. The pharmacological activity of the specific conjugate FUR-poly(L-lysine) -SF25MAb was higher than that of the drug-substituted polymer alone. The poly(L-lysine) bridge caused toxic effects in vivo, even though substituted both by FUR and by antibody. Therefore, the additional unreacted lysyl residues were blocked by succinylation. Partial blocking of free amino groups on the conjugate rendered it nontoxic but decreased its cell-binding capacity, though to a level still higher than that of the original unmodified antibody. The pharmacological activity of the specific conjugate after blocking was also reduced and necessitated prolonged incubation periods or higher concentrations. Following periodate oxidation and reduction, FUR was as effective as the clinically preferred compound 5-fluoro-2'-deoxyuridine in vitro and in vivo, against the LS180 colon carcinoma. Experiments in nude mice, with LS180 tumor subcutaneous xenotransplants, showed that FUR-poly(L-lysine)-SF25MAb (blocked by succinylation) was not toxic and was effective in the retardation of tumor growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMedDate not supplied

Improved detection of hepatitis B surface antigen (HBsAg) in blood donors by monoclonal radioimmunoassay.

We evaluated the performance of a monoclonal radioimmunoassay (M-RIA) with enhanced sensitivity and high specificity for hepatitis B surface antigen (HBsAg) in blood donors. The results were compared to a conventional RIA that used polyvalent antibodies (P-RIA). Analysis of 6409 American blood donors not reactive by P-RIA revealed an additional 1.4 HBsAg-positive donors per 1000 by M-RIA, or an approximate 60 percent, improvement in HBsAg detection rate. Furthermore, in 995 Israeli blood donors negative by P-RIA, 11 additional HbsAg-positive donors were identified. The 55 percent improvement in detection rate was similar to that observed with American blood donors. Since several of the newly identified HBsAg-positive blood donors had antibodies to the core antigen (anti-HBc) as the only serologic evidence of recent or past hepatitis B exposure, we studied an additional 68 anti-HBc-positive individuals with the M-RIA. It was found that 26 percent (18/68) reacted only by M-RIA and not by P-RIA. These findings suggest that there are blood donors with HBsAg undetectable by P-RIA.

Antibodies, Monoclonal↗

PubMedDate not supplied

Inhibition of lymphocyte cytotoxicity by serum from patients with alcoholic liver disease: partial characterization of serum inhibitors.

Studies were performed to explore the effect on normal lymphocyte function of serum derived from patients with alcohol-induced liver injury and healthy controls. We examined the effect of such serum on the generation of both spontaneous and Concanavalin A (Con A)-induced lymphocyte cytotoxicity for Chang target cells. Normal lymphocytes, when incubated in the presence of 5% serum from patients with alcoholic liver disease, showed a marked (20.75 ± 5.1% mean ± SEM) reduction in the capacity to generate spontaneously cytotoxic cells compared to 5% control serum (3.2 ± 1.9%) (p < 0.001). Similar results were found in studies of Con A-stimulated cytotoxicity (36 ± 7.2% vs. 5 ± 2.3%; p < 0.001). Fractionation of serum by gel chromatography demonstrated the presence of inhibitory activity of various molecular weights, although a major peak of inhibitory activity (approximately 270,000 daltons) was identified in severe alcoholic hepatitis. Thus, this study demonstrates the presence of serum inhibitors in alcoholic liver disease which influence normal lymphocyte function.

Antilymphocyte Serum↗