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T Stigbrand

Publications and source records attributed to T Stigbrand.

At least 127 records · Page 7Linked to original sources
PubMed1989

Hydrophobicity and lectin affinity of alkaline phosphatase isozymes in seminoma and normal testis.

Isozymes of alkaline phosphatases (ALP) in seminoma and normal testis were separated by use of high-performance liquid chromatography and a TSK-gel phenyl-5PW column. The tissue-nonspecific (liver) ALP (LAP) was the dominating isozyme, consisting of more than 90% ALP activity. The placental ALP (PLAP)-like enzyme contributed to 4-8% of the total ALP activity. The intestinal isozyme (IAP) could not be identified. The glycosylation patterns of the isozymes were studied using concanavalin A (Con A) affinity chromatography and batch elution with competing sugar. All PLAP activity in placental extracts and LAP activity in liver extracts was bound to Con A-Sepharose. In the tumor extracts, only 50-70% of the PLAP-like enzyme and 20-50% of the LAP activity from seminomas were bound to Con A-Sepharose. A similar binding pattern of the PLAP-like enzyme and LAP was also seen in the normal testes. This variability in Con A reactivity with PLAP or the PLAP-like enzyme was also reflected in serum of seminoma patients and of pregnant women. Thus, ALP expressed in seminoma has different lectin affinity characteristics compared with the same isozyme from placenta and liver, but almost identical to ALP in the normal testes. These findings imply that the PLAP-like enzyme and LAP in the testis can be discriminated from PLAP of placenta and LAP of liver by carbohydrate lectin affinity. It also supports the concept that the increased amounts of ALP in seminomas result from the enhanced eutopic expression of enzymes normally expressed in the testis.

Alkaline Phosphatase↗
PubMed1989

Electrophoretic heterogeneity of alkaline phosphatase isozymes in seminoma and normal testis.

Electrophoretic patterns of seminoma- and normal-testis-derived alkaline phosphatase isozymes, the placental alkaline phosphatase (PLAP)-like enzyme and the tissue-nonspecific (liver) alkaline phosphatase (LAP), were studied on starch gel and isoelectric focusing (IEF). Different migration patterns of the PLAP-like enzyme were observed with respect to both seminomas and normal testes on starch gel electrophoresis. On IEF, seminomas showed different staining patterns among different tumors; however, a common main activity was focused at pIs of 4.3-4.6, corresponding to pIs of PLAP. Normal testes showed two enzyme-staining regions, at pIs of 4.1 and 5.0-5.2, which were discriminated from pIs of PLAP and the PLAP-like enzyme in seminoma. The PLAP-like enzyme in seminoma was differentiated from PLAP by digestion with neuraminidase. Neuraminidase treatment simplified the distribution patterns of the PLAP-like enzyme in normal testis, but did not alter the pattern of microheterogeneity in seminoma. Two factors other than sialylation, namely structural modification of the carbohydrate moiety and variation of hydrophobicity, were shown to contribute to the microheterogeneity of the PLAP-like enzyme in seminoma. LAP in seminoma and in normal testis also showed marked electrophoretic heterogeneity and differences in pI distributions from LAP of liver. However, the migration patterns after desialylation were very similar to each other. The findings imply that electrophoretic heterogeneity demonstrated in LAP in seminoma and in normal testis is caused by a difference in sialic acid content in the molecule, and the heterogeneity of the PLAP-like enzyme in seminoma is considerable.

Alkaline Phosphatase↗
PubMed1989

Significance of alkaline phosphatase isozymes in the monitoring of patients with colorectal carcinoma.

The clinical course of colorectal carcinoma may be monitored by tumor markers such as carcinoembryonic antigen (CEA), carcinoma antigen (CA) 19-9 and CA-50. Alkaline phosphatase isozymes were previously used to study the clinical course of testicular and gynecologic tumors. In this study we investigated 8 patients with advanced colorectal carcinoma. Their sera were analyzed for the tumor markers CEA, CA 19-9, CA-50 and three alkaline phosphatase isozymes: the nonspecific liver isozyme LAP, the intestinal isozyme IAP and the placental isozyme PLAP. Rising levels of CEA, CA 19-9 and CA-50 were seen as expected, and PLAP also showed rising levels during tumor progression. LAP remained elevated. This indicates an association between progression of colorectal carcinoma and a raised serum content of alkaline phosphatase isozymes.

Adult↗
PubMed1989

Tumour radioimmunolocalization in nude mice by use of antiplacental alkaline phosphatase monoclonal antibodies.

Three monoclonal antibodies and their Fab and Fab'2 fragments with specificity against human placental alkaline phosphatase (PLAP) were evaluated for tumour immunolocalization of human PLAP-producing Hela Hep 2 tumours in nude mice. The antibodies and their fragments were labelled with 125I and injected intraperitoneally in mice with developing Hep 2 tumours. The animals were followed individually for 14 days with repetitive computerized gamma-camera recordings, which enable quantitation of several crucial parameters, i.e. the time-dependent antibody uptake in the tumours, decrease in background activity and tumour/background ratio. Excellent radioimmunolocalization was obtained with both the intact PLAP-specific immunoglobulins and their fragments but not with the nonspecific antibodies. No background subtraction had to be used. As much as 15% of the initially injected dose could be visualized in the tumours and for the uncleaved mab up to 80% of the radioactivity in the animals was retained in the tumours after 14 days, a considerably longer observation time than usually reported in such tumour xenograft models. The Fab and Fab'2 fragments were found to be excreted fast with less than 5% of the injected dose remaining in the animals after 48 h, but still with positive specific localization to the tumours after an initial high uptake in the kidneys. The results are encouraging and indicate significant potentials of the PLAP-antiPLAP mab system for immunolocalization studies in patients.

Adenocarcinoma↗
PubMed1989

Regional variations in cytokeratin expression in palmo-plantar epidermis.

The cytokeratin composition of palmo-plantar epidermis from sites with different degrees of mechanically induced thickening of the stratum corneum was analysed. The urea-soluble proteins of the stratum corneum were analysed by two-dimensional electrophoresis. Viable epidermal layers were analysed by immunofluorescence microscopy with polyclonal and monoclonal antibodies. A mouse monoclonal antibody specific for cytokeratin no. 9 was prepared for the study. Significant amounts of low molecular weight cytokeratins were found in suprabasal layers at sites with the most pronounced thickening of the stratum corneum. This was taken as evidence that palmo-plantar epidermis responds to mechanical stress with hyperproliferation. At sites where stratum corneum thickness is most increased this hyperproliferation appears to involve two different populations of cells--one capable of expressing high molecular weight, differentiation-related cytokeratins in the suprabasal epidermal layers, and one population that does not express these cytokeratins. At sites with intermediate epidermal hyperplasticity the high molecular weight cytokeratins were predominant in all suprabasal cells.

Adult↗
PubMed1988

Evidence for the expression of a primitive intestinal-like alkaline phosphatase in the intestinal 407 cell line.

Intestinal-like alkaline phosphatase was found to be expressed in the intestinal 407 cell line. This enzyme was identified by use of monoclonal antibodies specific for human placental (H7 and HPMS-1) and intestinal alkaline phosphatase (2HIMS-1 and 2HIMS-3) separately. Purification of this isozyme by use of two different monoclonal antibody immunoaffinity chromatographies demonstrates a single protein band on SDS-polyacrylamide gel electrophoresis indicating that this enzyme is not formed as a heterodimer. The apparent monomer subunit molecular weight and the dimer molecular weight of this isozyme were determined to 70000 and 160000, respectively. The enzyme is a homodimer according to molecular weight determinations. Furthermore, this isozyme is neuraminidase sensitive and comparatively heat stable, properties also characteristic for the placental enzyme. Our data suggest that the intestinal-like alkaline phosphatase in the intestinal 407 cell line displays properties intermediate of the intestinal and placental isozymes which may reflect the existence and reexpression of a new primitive isozyme.

Alkaline Phosphatase↗
PubMed1988

Three different conformational states of pregnancy zone protein identified by monoclonal antibodies.

Human pregnancy zone protein (PZP), related to human alpha 2-macroglobulin, forms dimeric/tetrameric (360/720 kDa) species. PZP binds proteinases which cause the cleavage of internal thiol esters in the molecule. Both the binding of proteinases, i.e. chymotrypsin, (CT) to PZP, forming PZP.CT complexes, or reaction with methylamine (MA) forming PZP.MA complexes, cause transition to a new similar conformational state. Reactivity of selected monoclonal antibodies against PZP towards the three PZP derivatives demonstrated differences in the reactivity pattern. PZP and PZP.MA share one determinant, which is missing on the PZP.CT complex. PZP after transition to PZP.CT, but not to PZP.MA, presents a neodeterminant detected by one of six monoclonal antibodies. The findings demonstrate that at least three different conformational states exist for PZP and its derivatives. Access to discriminating immunochemical tools makes possible an evaluation of the relative abundance of the different complexes in vivo.

Antibodies, Monoclonal↗
PubMed1988

In vivo evaluation of radiolabelled antibodies with antigen-coated polymer particles in diffusion chambers.

A method for the evaluation of in vivo immunolocalization of labelled monoclonal antibodies (MoAb) is presented. The technique is an alternative to the nude mouse xenograft system. The antigen reservoir is an intraperitoneal diffusion chamber (DC) filled with a suspension of antigen-coated polymer particles. Intravenously injected 125I-labelled MoAb are allowed to specifically bind to this artificial abdominal 'tumour', which can be removed and measured for radioactivity after animal killing. The model can be used as a preclinical in vivo method for the evaluation of labelled MoAbs prepared for immunodiagnostics or therapy. The DC system permits the amounts of both antibody and antigen to be controlled and antibody access to the antigen within the DC is presumably the same in every animal. The model permits a systematic comparison of different antibodies and antibody fragments, labels and labelling procedures, as well as routes of administration in immunocompetent animals.

Alkaline Phosphatase↗
PubMed1988

Immunohistochemical definition of antigenic determinants of pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) using monoclonal antibodies.

Human pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) is a high molecular weight glycoprotein in normal sera. The protein is present in high concentration in the sera of pregnant females and in abnormally low concentration in association with conditions connected with abnormalities of mucosal immunity. Indirect immunoperoxidase techniques using poly- and monoclonal antibodies were employed to identify pregnancy-associated alpha 2-PAG in different tissues. Four monoclonal antibodies were selected from a battery of antibodies with defined specificities in order to ascertain reactivity with various epitopes of the antigen. The antibodies were applied to paraffin sections of breast, colon, salivary gland, and tonsil, and different fixation regimes were used in the preparation of the tissues. The polyclonal antibodies were found to stain plasma cells and epithelial lumina evenly in all the tissues included whereas the monoclonal antibodies were shown to stain certain components selectively. In breast and salivary glands, all four monoclonal antibodies could identify alpha 2-PAG, but in tonsil and colon, only two were reactive. This difference in epitope expression might reflect the internal processing of alpha 2-PAG, and lack of availability of certain epitopes may be indicative of functional blocking of certain domains.

Antibodies, Monoclonal↗
PubMed1988

Antiestrogens do not counteract the inhibitory effect of estradiol-17 beta on the growth of the Dunning R3327 prostatic adenocarcinoma.

The purpose of this study was to investigate if the local effects of estradiol on the Dunning R3327 prostatic adenocarcinoma were estrogen-receptor mediated. All rats with the transplantable Dunning R3327 prostatic adenocarcinoma were castrated on the first day of treatment and were supplemented with daily s.c. injections of testosterone propionate (0.1 mg) during the treatment period, lasting for 6 weeks. The following treatment groups were studied: castration + testosterone supplementation (C + T, control group), C + T and estradiol-17 beta (50 micrograms/daily s.c.), C + T and tamoxifen (1 mg twice a week s.c.), and C + T and estradiol-17 beta in combination with tamoxifen. Tumor volumes were measured every week. At the end of the treatment period, pieces of the tumors were taken for morphological studies and estrogen-receptor analysis. In the groups of rats given tamoxifen treatment no estrogen-receptor binding was detectable in prostatic tumors, but, despite this, tamoxifen did not prevent either the inhibitory effect of estradiol-17 beta on the tumor growth rate or the estrogen-induced decrease of volume density of prostatic glandular epithelium. In contrast, the estrogen-induced increase of volume density of the stroma was abolished by tamoxifen, suggesting that this effect may be mediated by the estrogen receptor. A morphometrical method for estimating the growth of different tumor compartments is presented. Treatment with estradiol-17 beta, both with or without combined treatment with tamoxifen, reduced the growth of both the tumor epithelium and stroma. The direct effect of estradiol-17 beta on the growth and morphology of the Dunning R3327 prostatic adenocarcinoma seemed not to be mediated by the estrogen receptor.

Adenocarcinoma↗
PubMed1988

Profiles of epitope-defined markers in sera from patients with testicular germ cell tumors.

Epitope-defined tumor markers of AFP (FA), HCG (PM), PLAP (H7) and CEA (D/AH) were determined by monoclonal antibodies in sera of patients with germ cell tumors of the testis. Characteristic profiles of PLAP (H7) were seen in localized and metastatic seminoma and in sera of patients with mixed tumors with seminoma components. PLAP (H7) levels started to rise 10 months before clinical detection of recurrence in one case. Persisting elevated levels of PLAP (H7) in several cases were indicative of metastatic seminoma. PLAP (H7) occurred rarely in sera of patients with metastasing non-seminomatous tumors. AFP (FA) detected in seminoma sera led to identification of non-seminomatous disease in one case. High AFP (FA) alone occurred in yolk sac tumors, HCG (PM) with AFP (FA) or PLAP (H7) in patients where the tumors had components of teratoma and/or embryonal carcinoma, moderately elevated levels of AFP (FA) and sometimes also HCG (PM) occurred.

Alkaline Phosphatase↗
PubMed1988

Secretory pattern of growth hormone regulates plasma concentration of pregnancy-associated murine protein-1 in the non-pregnant rat.

Serum concentrations of pregnancy-associated murine protein-1 (PAMP-1) were followed in hypophysectomized adult female rats during treatment with oestradiol and continuous or intermittent human growth hormone (hGH). After hypophysectomy a rapid decrease in PAMP-1 values was recorded while concentrations of albumin and the acute phase alpha 2-macroglobulin were unaffected. PAMP-1 values were completely restored by continuous infusion of hGH (1.4 i.u./kg/day). Neither the same dose of hGH given as two daily injections nor oestrogen replacement treatment had any effect. It is concluded that the serum concentration of PAMP-1 in the non-pregnant rat is regulated by the sexually dimorphic secretory pattern of GH.

Animals↗
PubMed1988

Alkaline phosphatase isozymes in non-malignant intestinal and hepatic diseases.

Human alkaline phosphatase isozymes--the tissue-unspecific, the intestinal, and the placental alkaline phosphatases--were determined in sera by use of isozyme-specific monoclonal antibodies. The clinical utility of serum determinations of alkaline phosphatase isozymes was evaluated in patients with diseases of the gastrointestinal tract and the liver. No elevations of the different serum isozymes were observed in the intestinal diseases investigated (active Crohn's disease and ulcerative colitis). For non-malignant diseases of the liver the alkaline phosphatase isozymes presented characteristic patterns. Patients with cirrhosis due to hepatocellular diseases had markedly elevated levels of intestinal alkaline phosphatase and moderate serum activities of tissue-unspecific and placental alkaline phosphatases. In patients with liver disease with cholestatic features tissue-unspecific and placental isozyme levels were high, but the intestinal isozyme remained normal, whereas primary biliary cirrhosis was associated with high levels of the tissue-unspecific enzyme and moderate elevations of intestinal and placental alkaline phosphatases. It can be concluded that, in addition to tissue-unspecific alkaline phosphatase, intestinal and placental isozymes contribute to the total alkaline phosphatase activity for patients with liver disease. The results suggest that specific methods for the identification of alkaline phosphatase isozymes could be of value.

Alkaline Phosphatase↗
PubMed1987

A two-site monoclonal enzyme immunoassay for pregnancy-associated alpha 2-glycoprotein.

A two-site monoclonal enzyme immunoassay (MEIA) was developed for the determination of pregnancy-associated alpha 2-glycoprotein (PA alpha 2G) in serum. The minimum detectable level was 35 ng/ml. No immunochemical interaction with the closely related alpha 2-macroglobulin was found. Serum levels in 145 normal healthy males and non-pregnant females were 1.8 +/- 2.8 micrograms/ml (mean +/- SD), respectively, both significantly lower than previously reported. The distribution in the normal population was characteristically different when males and females were compared. No increase with age was found. During pregnancy, a significant increase in serum concentration was observed with average levels of 320 +/- 200 micrograms/ml at term (mean +/- SD), a 50-fold increase in concentration. As a tumor marker for breast and ovarian cancer, PA alpha 2G was found to be of no value. The present study emphasizes that a reevaluation of PA alpha 2G levels must be undertaken in order to assess the clinical and biological significance of this protein.

Antibodies, Monoclonal↗
PubMed1987

Patterns of seminoma tissue markers and deletions.

Seminomas and control tissues were analyzed for several tumor markers. Very high levels of placental alkaline phosphatase (PLAP)-like enzyme levels were found in all 18 seminomas studied. The majority of the seminomas were of phenotype I, thus differing from palcental PLAP. The mean amount of enzyme protein as measured by monoclonal antibodies, was 100 times higher than in non-malignant tissues and 10 times lower than in placental tissue. The specific enzymatic activity in seminomas was about half of that observed in placenta. Similarly, the specific activity of PLAP-like enzymes in sera of patients with seminoma was only about half of that found in pregnancy sera. HCG was strongly elevated in 3 seminomas, but not obviously related to PLAP. Thirteen of the 17 pure seminomas had HCG over 100 IU/g, which was not seen in normal testes. Liver alkaline phosphatase (LAP) and intestinal alkaline phosphatase (IAP) were high in seminomatous tissues, the mean increases being 60-fold and 20-fold, respectively. The highest IAP levels were found in 2 yolk-sac tumors. Ferritin was moderately elevated in seminomas, but high in several control tissues. Carcinoembryonic antigen (CEA) was not elevated and alpha-fetoprotein (AFP) was not detected at all in pure seminomas. A decrease in carbohydrate antigen 50 (CA-50) content was noted in seminomas as compared to normal testes, yolk-sac tumors and choriocarcinomas. Defects in tumor-related enzymes may account for increase of PLAP and decrease of CA-50.

Alkaline Phosphatase↗
PubMed1987

Specific assays for human alkaline phosphatase isozymes.

Specific assays for human intestinal and liver alkaline phosphatases were developed by use of isozyme specific monoclonal antibodies bound to paper discs. The assays are fast, specific and convenient to use as demonstrated by determinations of alkaline phosphatase isozymes in sera and tissues. In sera from forty healthy individuals the activity of the tissue unspecific alkaline phosphatase was determined to 32 +/- 12 IU/l (mean +/- SD). The activity of the intestinal alkaline phosphatase was found to be ten-fold lower, 3.5 +/- 6.3 IU/l (mean +/- SD), and of the placental alkaline phosphatase another ten-fold lower, 0.3 +/- 0.2 IU/l (mean +/- SD), than that of the tissue unspecific alkaline phosphatase. Several normal tissues contained all three isozymes, the intestinal mucosa, for example, which besides intestinal alkaline phosphatase also expresses trace amounts of placental and liver-bone-kidney alkaline phosphatase. Seminomas, known to express eutopically placental-like alkaline phosphatase were demonstrated to contain increased levels of both intestinal and liver-bone-kidney alkaline phosphatases as compared to the normal testis.

Alkaline Phosphatase↗
PubMed1987

Antigenic pattern of human brain glycoproteins as described by monoclonal antibodies.

A battery of monoclonal antibodies was raised against a preparation of lentil lectin-binding membrane glycoproteins from human brain. Out of 26 established hybridomas, nine produced antibodies against the human Thy-1 antigen. For the remaining 17 lines, reactivity with at least six other antigens could be identified after immunoprecipitation and immunoblotting. Several of the antigens were di- or trimeric, mainly in the molecular weight range of 60-120 kDa. Two of the antibodies were reactive with high-molecular-weight aggregates and four targets for the antibody reactivity were not identifiable by immunoprecipitation of iodinated antigens. Three of the identified antigens were shown by quantitative enzyme-linked immunosorbent assay tests on various human tissues to be specifically expressed in the brain.

Animals↗