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Biomedical subjects

I Damjanov

Publications and source records attributed to I Damjanov.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of biological response modifiers in the enhancement of tumor uptake of technetium-99m labeled macromolecules. A preliminary report.

Imaging tumors with radioactive monoclonal antibodies remains attractive but continues to be challenging. With the hypothesis that the use of biological response modifiers (BRMs) may augment the tumor uptake, technetium-99m(99mTc)-labeled tumor necrosis factor (TNF) and nuclear histone specific TNT-1-F(ab')2 were evaluated in tumor bearing mice given a single dose of interferon (IFN). Ukrain or pokeweed mitogen as BRMs. As early as 1.5 h post injection (p.i.) of the radioactive macromolecules, the absolute tumor uptake (% administered dose/g) of each agent was enhanced (e.g., TNF, control = 1.8 +/- 0.4, Ukrain = 3.2 +/- 0.5, P = 0.006) and tumor to muscle ratios were elevated (e.g., TNF, control a 4.1 +/- 2.2, interferon 8.3 +/- 2.7, P = 0.01). The absolute tumor uptake remained practically unchanged at 4 h p.i. Generally with BRMs, the blood clearance was rapid and tumor/blood ratios and tumor/muscle ratios were higher than in the control group, increasing to greater than 200% for IFN as a BRM. The early enhancement in tumor uptake of macromolecules, leading to excellent delineation of tumors by scintigraphy is highly encouraging and warrants further studies to explore the full potential of BRMs.

Animals↗
PubMed1992

Analysis of purified human liver alpha-L-fucosidase by western-blotting with lectins and polyclonal and monoclonal antibodies.

Western-blot analysis [with lectins, polyclonal antibodies (pAbs) and four monoclonal antibodies (mAbs)] was employed to investigate the structural relationship between the separated isoforms and subunits of purified human liver alpha-L-fucosidase. SDS/PAGE and Western-blot analysis indicated the presence of two protein bands of 51 kDa and 56 kDa that were recognized by the pAbs. Polyacrylamide-gel isoelectric focusing (PAG-IEF) followed by blotting indicated that the pAbs and mAbs recognized at least five fucosidase isoforms (pI values 3.6-6.0). Lectin blotting indicated an enrichment of sialic acid residues in the more acidic isoforms. Western-blot analysis indicated that four mAbs recognized the 51 kDa subunit and at least two mAbs recognized the 56 kDa subunit. The subunit composition of the isoforms (separated by PAG-IEF) of human liver alpha-L-fucosidase was investigated by SDS/PAGE. One or two closely spaced bands were found for each isoform with a trend of increasing relative amounts of the high-molecular-mass band in the more acidic isoforms relative to the more neutral isoforms. Neuraminidase treatment of alpha-L-fucosidase resulted in a decrease in the amount of the high-molecular-mass subunit and an increase in the amount of the low-molecular-mass subunit, suggesting that these subunits are related at least in part by sialic acid residues. In addition, blotting with lectins indicated the presence of sialic acid residues only in the high-molecular-mass subunit. N-Glycanase treatment led to the disappearance of the glycosylated 56 kDa and 51 kDa protein bands and the appearance of non-glycosylated protein bands at 48 kDa and 45 kDa. The overall results indicate that (1) N-glycosylation contributes to, but does not account completely for, structural differences in the fucosidase subunits and (2) the more acidic isoforms of fucosidase contain enriched relative amounts of the sialylated high-molecular-mass subunit.

Animals↗
PubMed1992

Transdifferentiation of murine squamous vaginal epithelium in proestrus is associated with changes in the expression of keratin polypeptides.

The superficial layers of the stratified squamous epithelium of the murine vagina undergo transdifferentiation into cuboidal mucinous cells during the proestrus phase of the normal estrous cycle. In contrast to their squamous progenitor cells which have the cytoskeletal characteristics of squamous epithelium, mucinous cells express keratin polypeptides typical of simple nonstratified epithelia. Accordingly, the transdifferentiation of squamous cell into mucinous cells involves not only a change in cell morphology but also a switch in the expression of keratin polypeptides. These data indicate that the stratified squamous cells of the vagina are not terminally differentiated and their phenotype can be hormonally modulated.

Animals↗
PubMed1992

Lectin cytochemistry of mouse vaginal smears.

Lectin cytochemistry was used to determine whether phase-specific changes could be detected in the smears of mouse vagina taken during the different phases of the estrous cycle. The strongest and most specific lectin reactivity was seen in the proestrus phase of the cycle. Several lectins reacted with mucinous cells typical of the proestrus phase and stained either diffusely the entire cytoplasm or only the cytoplasmic granules of desquamated cells. Nucleated squamous epithelial cells showed reactivity of the cell membrane or the entire cytoplasm in late metestrus and diestrus phase. Cornified squamous cells were essentially unreactive with the lectins tested in this study. Lectin cytochemistry is a reliable method for identification of mucinous cells in mouse vaginal smears and for establishing the cyclicity of the mouse estrous cycle.

Animals↗
PubMed1992

Changes related to the oestrous cycle in the expression of endometrial and oviductal proteins of mice.

Soluble proteins extracted from the endometria and oviducts of normal sexually mature cycling Swiss Webster mice were analysed by two-dimensional high-resolution sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Thirty endometrial and 25 oviductal proteins showed differential expression related to the oestrous cycle. In the endometrium, 19 proteins were maximally expressed in the oestrous phase, and significantly decreased or could not be detected in dioestrus. Eleven additional proteins were more prominent in dioestrus. Most of these endometrial cyclic proteins were acidic. In the oviduct, almost two-thirds of cycle-related, differentially expressed proteins were more strongly expressed in dioestrus and were significantly less prominent or could not be detected in the oestrous phase. In contrast to the endometrial proteins, most of the oviductal cyclic proteins were basic. Fourteen proteins appeared to be identical in both organs, and five of these showed the same cyclic pattern of expression. The remaining cyclic proteins were organ specific and showed uterus- or oviduct-specific changes during the oestrous cycle. Among the cyclic proteins, four endometrial and two oviductal proteins were restricted to oestrus, whereas two endometrial and seven oviductal proteins were restricted to dioestrus. These proteins could serve as markers for specific phases of the oestrous cycle. Our data show that the mouse oestrous cycle is associated with consistent and predictable changes in protein expression in both the endometrium and oviduct.

Animals↗
PubMed1992

Isolation of serine protease from granulated metrial gland cells of mice and rats with lectin from Dolichos biflorus.

Granulated metrial gland cells were the only cells in the endometria of pregnant mice and rats that reacted histochemically with fluoresceinated lectin (DBA) from Dolichos biflorus. Cell extracts of uteri of pregnant animals, separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and analysed by lectin overlay blotting, contained DBA-reactive, 40-50 kDa, doublet glycoprotein bands. This glycoprotein was purified on a DBA agarose affinity column. It was identified by amino acid sequencing as a serine protease closely related to granzymes of T lymphocytes. We conclude that this granzyme accounts for the selective reactivity of granulated metrial gland cells with fluoresceinated DBA in histological sections of uteri of pregnant rodents and show that DBA affinity columns can be used for purification of granzyme derived from granulated metrial gland cells.

Amino Acid Sequence↗
PubMed1991

Lectin histochemistry of mouse vagina during the estrous cycle.

Estrous cycle-related histochemical changes in the vaginal epithelium of sexually mature female mice were studied with 30 fluorescein isothiocyanate (FITC)-labeled lectins. On the basis of the staining pattern the lectins were divided into five groups: I, seventeen lectins that reacted with mucinous surface layer of proestrus. This group comprised two subgroups: Ia, seven lectins that reacted exclusively with the mucinous layer, and Ib, ten lectins that reacted with mucinous cells and the underlying squamous epithelium of proestrus; II, two lectins that reacted with squamous epithelium of proestrus only but were unreactive with mucinous cells; III, three lectins that reacted in a phase-specific manner with squamous epithelium; IV, six lectins that showed increased luminal surface reactivity in diestrus and/or metestrus; and V, eleven lectins that were unreactive with vaginal epithelium. These data indicate that the cyclic changes in the morphology of the vaginal epithelium are accompanied by distinct lectin reactivity patterns.

Animals↗
PubMed1990

Yolk-sac carcinoma develops spontaneously as a late occurrence in slow-growing teratoid tumors produced from transplanted 7-day mouse embryos.

Seven-day embryos of BALB/c mice transplanted underneath the kidney capsule of adult syngeneic recipients form either benign teratomas or teratocarcinomas, which can be distinguished from one another histologically at 8 weeks post-embryonic transplantation. Embryo-derived (ED) teratomas were allowed to remain in the host for an additional period up to 1 year after embryo transplantation, to test their malignant potential. It was found that a considerable number of slow-growing small tumors derived from embryonic transplant give rise to parietal yolk-sac carcinomas. A proportion of these tumors contained foci of visceral yolk-sac and trophoblastic differentiation, which gradually disappeared in successive transplantations. We conclude that parietal yolk-sac carcinoma develops as a late event in some ED teratomas. These malignant tumors originate either from small foci of yolk sac originally included in the grafted embryo or, more likely, from the yolk sac formed from the differentiating embryonic stem cells.

Animals↗
PubMed1990

Effects of alcohols on mouse embryonal carcinoma-substrate adhesion.

The effects of ethanol and closely related alcohols on the cell-substrate adhesion of embryonal carcinoma cells were studied in microtiter wells using the enzyme cytochemical alkaline phosphatase technique and an ELISA reader. Three embryonal carcinoma cell lines (NF-1, NE and F9) were used. Prior to plating of cells the wells were coated with laminin, fibronectin or collagen type I. NF-1 cells adhered only to laminin; NE adhered to all substrata and uncoated wells equally well; F9 adhered only to fibronectin and laminin coated wells. Ethanol reduced the binding of cells to laminin and collagen type I but did not affect the binding of NE or F9 cells to fibronectin. The effect of ethanols was dose dependent; it lasted as long as an adequate concentration of this alcohol was maintained in vitro, and it was reversible. Other short chain alcohols inhibited the binding of cells to laminin proportionately to their membrane/buffer partition coefficients. These data show that various embryonal carcinoma cells differ with regards to their capacity to adhere to different extracellular matrix components. Cell adhesion to some but not all substrates can be prevented by ethanol and related short chain alcohols. The effects of alcohols on the adhesion of embryonal carcinoma cells to various substrates may be relevant for the elucidation of the fetal alcohol syndrome.

Alcohols↗
PubMed1990

Expression of villin in the mouse oviduct and the seminiferous ducts.

Villin, a 95-kD cytoskeletal protein selectively expressed in the microvilli of some absorptive cells was localized immunohistochemically in the oviduct and the seminiferous excretory ducts of the mouse. Villin was found in the proximal part of the oviduct, comprising the preampulla, ampulla, and part of the isthmus. Distal to the isthmus the oviductal cells lining the junctura and the intrauterine colliculus tubaris were devoid of villin. No villin could be detected in the uterine cells. Ductuli efferentes, connecting the rete testis with the epididymis were the only portion of the male seminiferous ductal system expressing villin. The cells lining the epididymis and the vas deferens were devoid of villin. These data show that villin is selectively expressed in male and female reproductive systems and that it is limited to anatomically defined proximal portions of the reproductive ducts.

Animals↗