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Biomedical subjects

E Engvall

Publications and source records attributed to E Engvall.

At least 145 records · Page 8Linked to original sources
PubMed1979

Is SP1 (pregnancy specific beta 1 glycoprotein) elevated in cancer patients?

Pregnancy-specific beta 1-glycoprotein, SP1, was measured in serum by competitive double antibody radioimmunoassay. Very low levels of SP1 or SP1-like activity were found in only 2 out of 85 sera from patients with cancer of the digestive tract, breast cancer, melanoma, and sarcoma, in 2 out of 11 sera from patients with infectious diseases, and in none out of 15 sera from non-pregnant healthy individuals. SP1 thus does not seem to be ectopically produced in vivo by the types of cancer studied, but is probably highly specific for the normal and malignant trophoblast.

Breast Neoplasms↗
PubMed1979

Immunofluorescent localization of fibronectin in the human kidney.

Fibronectin is a glycoprotein shown previously to be present on the surfaces of cells, connective tissue matrices, and in extracellular fluids. Its distribution in the human kidney was evaluated by immunofluorescence methods studying 65 renal biopsies with a variety of pathologic disorders. Fibronectin was found in the mesangium of the normal kidney and increased proportionately in the disease states characterized by mesangial expansion. It was visualized in glomerular capillary loops in some biopsies with membranoproliferative glomerulonephritis, diffuse proliferative glomerulonephritis, and membranous nephropathy. Additionally, fibronectin was detected in glomerular crescents, diabetic nodules, vascular thrombi, glomerular sclerosis, and variably in the interstitium.

Fibronectins↗
PubMed1978

Developmental changes in carbohydrate moiety of human alpha-fetoprotein.

Human AFP purified from fetal serum and amniotic fluid was separated into three different variants by chromatography on concanavalin A insolubilized on Sepharose (Con A--Sepharose). The three variants were indistinguishable in immunodiffusion and radioimmunoassay. Sera from patients with yolk-sac tumor and amniotic fluid from early pregnancy were found to contain a high proportion (15-45%) of AFP which does not bind to Con A, while AFP in fetal and newborn sera, and in amniotic fluid from late pregnancy, contained less (2-6%) of this variant. The use of a large excess of Con A--Sepharose and the fact that the non-bound AFP consistently eluted as non-bound in rechromatography showed that this AFP is non-reactive with Con A. Fractionation of radiolabelled AFP from cord serum in a mixture with amniotic fluid verified the difference in the amount of the Con-A nonreactive variant in AFP from these two sources. These results suggest that AFP synthesized by the yolk-sac tissue and by the liver are glycosylated differently. The variant may prove to be diagnostically useful.

Amniotic Fluid↗
PubMed1978

Affinity of fibronectin to collagens of different genetic types and to fibrinogen.

Fibronectin, a fibroblast surface protein, was purified from human and chicken plasma and extracts of cultured chicken fibroblasts with affinity chromatography on gelatin coupled to Sepharose particles. A fibronectin-like protein was also isolated from the plasma of Torpedo fish. The collagen binding properties of fibronectin were studied with several genetically distinct collagens. Heat denatured types I, II, and III collagens were equal in their binding capacity and more active than the native collagens or A and B chains. Native type III collagen was more active than the other native collagens. Human and chicken fibronectins showed approximately the same pattern of specificity. Identical specificities were shown by the plasma and fibroblast forms of chicken fibronectin. Two cyanogen bromide peptides of the collagen alpha1 (II) chain, CB8 and CB12, derived from different parts of the chain, were active in fibronectin binding. A polymer of the tripeptide pro-gly-pro, and polyproline were inactive. Fibronectin also binds to fibrinogen and fibrin. Comparison of this binding to collagen binding showed that fibrinogen inhibited binding of fibronectin to collagen, but was less active than native collagen. Two other fibrous proteins, tropoelastin and keratin, did not bind fibronectin. The binding of fibronectin to fibrinogen was inhibited by collagen and incorporation of fibronectin into blood clot in the cold was inhibited by gelatin. These results suggest that the binding of fibronectin to collagen and fibrinogen depends on the same binding site in the fibronectin molecule. It is proposed that cell surface fibronectin mediates attachment of cells to the collagenous extracellular matrix and to a temporary fibrin matrix in a wound.

Animals↗
PubMed1978

Early increase of serum alpha-fetoprotein in spontaneous hepatocarcinogenesis in mice.

The concentration of serum alpha-fetoprotein (AFP) was followed in C3H mice having a high incidence of spontaneous liver-cell cancer. No general elevation of serum AFP level with age was seen in mice without tumor. With a single exception, mice bearing hepatocellular carcinomas had increased serum AFP levels. In some mice this increase followed a biphasic course. Mice killed within 1 month of the time when an elevation of serum AFP was first observed had small tumors or no detectable tumor. Premalignant lesions were present in the livers of 11 out of 16 mice that had elevated AFP but no cancer, while only one out of 14 mice with normal AFP had such alterations. Our results strongly suggest that spontaneous hepatocarcinogenesis proceeds through almost the same premalignant lesions as chemically induced carcinogenesis, and that an increase in AFP production occurs early during this process, often preceding macroscopic lesions. Autologous antibodies to AFP were produced in a group of C3H mice by immunization with rat AFP. These anti-AFP antibodies reduced the amount of serum AFP but had no effect on the incidence of spontaneous hepatomas.

Animals↗
PubMed1978

Detection of trophoblastic tumour activity by pregnancy-specific beta-1-glycoprotein.

Pregnancy-specific beta-1-glycoprotein (PSBG) and human chorionic gonagotrophin (hCG) were measured by specific radioimmunoassays in 73 serum samples from eight patients treated for gestational choriocarcinoma. Both markers were initially present in all cases, but at the time of writing both had levelled off in six cases and decreased markedly in two. Usually hCG was detectable for longer than PSBG during the course of chemotherapy. Both PSBG and hCG reappeared on clinical recurrence. However, at times during the follow-up period one trophoblastic marker only was expressed. This was hCG in most cases, but in one case PSBG alone was encountered. These results suggest that PSBG may serve as an additional marker for the detection of residual tumour growth in patients with trophoblastic tumours.

Choriocarcinoma↗
PubMed1978

Isolation and characterization of the normal crossreacting antigen: homology of its NH2-terminal amino acid sequence with that of carcinoembryonic antigen.

The normal antigen, NCA, which crossreacts with the carcinoembryonic antigen, CEA, was purified from normal spleen tissue by an immunochemical purification method using insolubilized antibodies to either CEA or NCA. The highly purified NCA obtained was extensively characterized by immunological tests. The molecular weight of NCA determined by chromatography on Sephadex G-200 was approximately 100,000. The total amount of carbohydrate in NCA was 30%, compared to 60% in CEA. NCA and CEA also differed in sugar composition. The amino acid composition of NCA was nearly identical to that of CEA, except for the apparent presence of methionine in NCA but not in CEA. The sequence of the first 26 NH2-terminal amino acids in NCA was identical to that of CEA except at position 21, where alanine was found in NCA instead of valine in CEA.

Amino Acid Sequence↗
PubMed1978

A solid phase enzyme-linked immunosurbent assay (ELISA) for the demonstration of antibodies against denatured, single-stranded DNA in patient sera.

A solid phase enzyme-linked-immunosorbent assay (ELISA) for the determination of antibodies against denatured, single-stranded (ss-) DNA is described. Polystyrene cuvettes coated with ss-DNA were incubated with serum samples and the anti-ss-DNA antibodies bound were detected by means of an anti-IgG-alkaline phosphatase conjugate. The binding of anti-ss-DNA antibodies in individual sera was expressed as units calculated as % of the absorbance in relation to the absorbance value obtained with a reference pool. Absorption experiments showed that the assay is specific for antibodies against denatured DNA. By using immunologically purified anti-ss-DNA antibodies the assay was shown to detect specific antibodies in concentrations down to 1 ng/ml. Antibodies against DNA could be detected in 94% of sera with antinuclear antibodies.

Antibodies, Antinuclear↗
PubMed1978

Pregnancy-specific beta 1-glycoprotein and chorionic gonadotropin-like immunoreactivity during the latter half of the cycle in women using intrauterine contraception.

In a cross-sectional study, the serum levels of pregnancy-specific beta 1-glycoprotein (PSBG), hCG, human LH, and progesterone were measured by RIAs during 94 mid or late luteal phases of 69 women using oral contraceptives. Subsequent spontaneous menstruation took place in every cycle. None of the women using oral contraceptives had any PSBG or hCG-like immunoreactivity in serum. In women with intrauterine devices, PSBG was found in six cycles (6.4%) and hCG-like immunoreactivity was demonstrated in one cycle only, where PSBG also was present. In two out of six PSBG-positive cycles, menstruation was delayed by 5 and 16 days. Although rare, the transient occurrence of trophoblastic antigens in women using intrauterine contraception is taken as evidence for an occult pregnancy in these apparently infertile cycles.

Chorionic Gonadotropin↗
PubMed1978

Immunochemical properties of alpha-fetoprotein (AFP) and antibodies to autologous AFP.

Alpha-fetoprotein (AFP) is a strong immunogen when injected into another species, but does not elicit an immune response in the species of origin of the AFP. AFPs from different mammalian species are crossreactive. AFP and albumin show sequence homology. They do not crossreact in their native state, but their unfolded (reduced and carboxamidomethylated) forms are immunologically crossreactive. Antibodies to autologous AFP can be induced in animals by immunization with heterologous or modified homologous AFP. These antibodies eliminate the AFP normally measurable in the serum and delay the elevation of serum AFP caused by hepatomas, but do not protect against such tumors.

Amniotic Fluid↗
PubMed1977

Antigenic differences in nuclear proteins of normal liver and hepatoma. Identification of a nuclear protein present in hepatocytes but absent in hepatoma cells.

A nuclear antigen was detected in the mouse liver nonhistone protein fraction by using antibodies to whole liver cells. The antigen was purified to homogeneity from perchloric acid extracts of liver tissue. It gave a single band corresponding to tool wt 21,000 in sodium dodecyl sulfate gel electrophoresis. Amino acid and carbohydrate analysis showed predominance of the acidic amino acids, lack of proline, and absence of carbohydrate. Immunofluorescence staining of liver sections confirmed the nuclear localization of the antigen. Its tissue distribution was studied by using radioimmunoassay. Of the various tissues extracted for analysis, the liver contained the highest amounts of the antigen, about 1 mug/mg of solubilized liver protein. Other tissues examined showed 2-4 percent of the amount of antigen present in the liver. Two transplantable hepatomas in C3H/HeJ and C57L/J mice, respectively, and three spontaneous C3H hepatomas showed greatly decreased levels of the antigen compared to normal liver. The amount of antigen in hepatomas varied from nondetectable to 2 percent of the amount of antigen found in the livers of the mice. The antigen was also found in the blood. The antigen was found in high concentrations (up to 13 mg/ml) in the urine of normal mice. This suggests identity with the previously known mouse urinary protein (MUP). In addition to the extremely high urinary output, the properties found to be shared by MUP and the nuclear antigen included similar serum concentrations (2-60 mug/ml), a sex difference with lower values in females, same molecular size as determined by gel filtration, and immunological identity. The nuclear localization of MUP and its disappearance from hepatomas suggest that it may have an important regulatory function.

Animals↗
PubMed1977

Binding of soluble form of fibroblast surface protein, fibronectin, to collagen.

Fibronectin, a plasma protein immunologically identical with a major surface protein of normal fibroblasts, was found to bind to collagen and gelatin. A solid phase enzyme immunoassay was used for the binding tests. Collagen, gelatin or various control proteins were adsorbed to a plastic surface. Binding of fibronectin was detected using purified fibronectin antibodies conjugated to alkaline phosphatase. Circulating fibronectin and fibronectin obtained from fibroblast cultures both showed specific binding to collagen and gelatin. Preparative affinity chromatography of plasma on gelatin coupled to Sepharose gave electrophoretically and immunologically pure fibronectin in high yields. Malignantly transformed fibroblasts lack surface fibronectin. Our findings suggest the possibility that this results in a lack of anchorage to the surrounding intercellular matrix, which could contribute to the malignant growth behavior.

Blood Proteins↗
PubMed1977

Detection of circulating tumor antigens.

A wide variety of malignancies have associated tumor antigens. Two which have proven useful in the clinical detection and management of cancer are alphafetoprotein (AFP) and the carcinoembryonic antigen (CEA). These materials have been determined both by radioimmunoassay and by a newer technique employing enzymes to replace radioisotopea as markers. The interpretation of these immune assay results and the factors governing the shape of the standard curve are discussed. The advantages of 57Co over 22Na as a volume marker in radioimmunoassay are presented.

Animals↗
PubMed1977

Effect of specific immunotherapy with preimmunization against alpha-fetoprotein on a mouse transplantable hepatoma.

Antibodies to autologous alpha-fetoprotein (AFP) were produced in mice by immunization with rat AFP. C57L/J mice with or without such antibodies were inoculated sc or ip with controlled numbers of cells of the syngeneic, AFP-producing, BW 7756 hepatoma. There was a linear relationship between circulating AFP and tumor mass, with elevated AFP being detectable earlier than the tumor. The AFP levels of the immunized mice were generally lower than those of control mice, and tumors could be detected before elevated concentrations of AFP appeared in the circulation. An extensive series of transplantations with varying protocols for immunization did not protect against tumor and did not affect the rate of tumor growth.

Animals↗