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Biomedical subjects

K Pollow

Publications and source records attributed to K Pollow.

At least 109 records · Page 6Linked to original sources
PubMed1979

Comparison of acidic and basic chromosomal proteins from normal human endometrium and undifferentiated endometrial carcinoma by isoelectric focussing and microgel-electrophoresis.

In the study reported here, non-histamine chromosomal proteins from proliferative and secretory human endometrium, and from undifferentiated endometrial carcinoma have been separated into more than 750 protein components, using a new preparative and highly sensitive analytical method. The following experimental procedure was applied: 1. Dissociation of chromatin under different conditions (variable parameters: ion strength, dissociation agents, shearing, pH), 2. cation exchange chromatography over Bio Rex, 3. preparative fractionation of those non-histamine chromosomal proteins which are not adsorbed on Bio Rex 70 in a Valmet-electrofocusing apparatus, 4. micro-electrophoresis of the focused proteins in microgels containing a continous gradient of polyacrylamide, 5. two-dimensional electrophoresis of the strongly basic chromosomal proteins. There are qualitative differences with respect to the components of this class of proteins between proliferative and secretory endometrium and endometrial carcinoma. The relevance of these results to the control of gene activity is discussed.

Chromatin↗
PubMed1978

A new high sensitive analytical micro-scale procedure for chromosomal proteins.

Utilizing male rat liver cells we describe a method for isolating and fractionating chromosomal proteins. About 99% of chromosomal proteins was dissociated using a three step dissociation procedure. DNA was removed by sedimentation and the histone fractions were separated from the non-histone chromosomal proteins by Bio Rex 70 chromatography. The non-histone chromosomal proteins were fractionated by micro-gradient electrophoresis on SDS-polyacrylamide gels, which proved to be superior to the electrophoretic procedures currently in use. The histones were further separated on polyacrylamide-SDS slab gels using a micro-two-dimensional electrophoretic system. The high resolution of these fractionation procedures greatly enhances the possibility of observing small changes in proteins which may play a role in gene regulation.

Animals↗
PubMed1978

In vitro conversion of estradiol-17beta into estrone in normal human myometrium and leiomyoma.

The specific activity of 17beta-hydroxysteroid dehydrogenase was measured in normal human myometrium, and in leiomyoma specimens obtained from the same tumor-bearing uterus. In all cases the normal tissue showed greater conversion of estradiol-17beta into estrone than the neoplastic tissues. In normal myometrium of fertile women, the specific enzyme activity depended on the phase of the menstrual cycle, the highest values of 17beta-hydroxysteroid dehydrogenase activity being found in the early secretory phase. To determine the intracellular distribution of the 17beta-hydroxysteroid dehydrogenase, purified microsomes, mitochondria, nuclei and cytosol fractions were prepared. The purity of each fraction was monitored by marker enzymes. It was found that the enzyme was mainly located in mitochondria and microsomes. Furthermore it was demonstrated that the microsomal enzyme was bound tightly to the membranes of the endoplasmic reticulum, while the mitochondrial 17beta-hydroxysteroid dehydrogenase was mainly associated with the outer membranes of the organelle. Kinetic parameters (Km-values, coenzyme requirements, temperature and pH-optima) of the cytoplasmic, nuclear, mitochondrial and microsomal enzyme of normal and neoplastic tissue were compared.

17-Hydroxysteroid Dehydrogenases↗
PubMed1978

Estrogen and progesterone binding proteins in normal human myometrium and leiomyoma tissue.

The occurrence and characteristics of macromolecular components of normal human myometrium and leiomyoma which bind [3H]estradiol and [3H]progesterone were investigated, employing dextran coated charcoal, density gradient centrifugation and gel filtration techniques. On sucrose density gradient centrigugation, [3H]progesterone was bound by macromolecules with sedimentation rates of about 4 S and 8 S. The major [3H]progesterone binding component had a sedimentation coefficient of about 4 S, which contained specific and nonspecific binding sites. Sedimentation patterns as well as elution profiles from agarose gel revealed a striking similarity between biochemical properties of the progesterone receptors from normal myometrium and leiomyomas of the same organ. Both progesterone and estradiol receptor change in concentration during the normal menstrual cycle. During the early proliferative phase the number of estradiol receptor binding sites was highest; after ovulation, a rapip decrease of estradiol receptor level was seen. On the other hand, using [3H]progesterone as the ligand, the highest receptor concentration was found at midcycle. The leiomyoma steroid hormone receptor levels were compared with those in normal myometrium. Whereas leiomyoma exhibited higher estradiol binding capacity, the concentration of progesterone receptors was low in fibroid tumors.

Carrier Proteins↗
PubMed1977

Comparison of the in vitro conversion of estradiol-17 beta to estrone of normal and neoplastic human breast tissue.

Specific activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) was measured in 48 tissue specimens of human female breast cancer and, in addition, 48 nonmalignant tissue specimens obtained in each case from the same cancer-bearing breast. In all cases the nonmalignant tissue showed greater conversion of estradiol-17 beta into estrone than the neoplastic tissues. In normal human breast tissue of premenopausal women specific enzyme activity depended on the phase of the MENSTRUAL CYCLE: the highest values of 17 beta-HSD activity were found in the early secretory phase. To determine the intracellular distribution of the 17 beta-HSD, purified microsomes, mitochondria, peroxysomes, lysosomes, nuclei and cytosol fractions were prepared. The purity of each fraction was monitored by marker enzymes. It was found that the 17 beta-HSD was mainly located in mitochondria and microsomes. Furthermore it could be demonstrated that the microsomal enzyme was bound tightly to the membranes of the endoplasmic reticulum, while the mitochondrial 17 beta-HSD was mainly associated with the outer membranes of the organelle. Kinetic parameters (Km-values, coenzyme requirements and maximal velocities) of a cytoplasmic, nuclear, mitochondrial and microsomal 17 beta-HSD of normal and neoplastic human mammary tissue were compared. Maximal velocity was highest in enzyme preparations of normal mammary tissue obtained from premenopausal women in the early secretory phase. Km-values wrere nearly identical in normal and neoplastic mammary tissue preparations (approx. 1 X 10(-6) M). NAD was more efficient than NADP as a cofactor. For the conversion of estradiol to estrone the optimum temperature was approximately 40 degrees C and the optimum pH 9.5. For the reduction of estrone the optimum pH was 6.5. Sulphydryl groups were shown to be essential for catalysis.

Breast↗
PubMed1976

[Effect of gestagen therapy upon estradiol- and progesterone-receptor-level and 17beta-hydroxysteroid dehydrogenase in human endometrial adenocarcinoma (author's transl)].

Oestradiol was converted to oestrone about ten time more rapidly by subcellular fractions of normal human endometrium of the secretory phase than by tissue of the proliferative phase. In subcellular fractions of endometrial carcinoma the 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity decreased with decreasing differentiation of the tumour. Most of the 17beta-HSD activity was located in mitochondrial and microsomal fractions of both normal and neoplastic endometrium. After treatment of patients with gestagens only the well differentiated carcinomata significantly increased in 17beta-HSD activity demonstrating that the hormonal stimulus leads to similar effects on the 17beta-HSD activity as in normal endometrium. Furthermore quantitative aspects of the in vitro binding of 3H-oestradiol and 3H-progesterone to receptor components from normal endometrium and endometrial carcinoma cytoplasmic fractions have been studied. In normal tissue the number of cytoplasmic binding sites for both oestradiol and progesterone varied dramatically during the menstrual cycle: number of oestradiol binding sites were highest during the proliferative phase and fell during the secretory phase; for progesterone site the contrary was the case. In all endometrial carcinomata high oestradiol binding activity was observed. In contrast the number of progesterone sites in the tumours was related to the state of differentiation, which paralled the progestional sensitivity of these tumours.

Adenocarcinoma↗
PubMed1975

Characterization and comparison of receptors for 17 beta-estradiol and progesterone in human proliferative endometrium and endometrial carcinoma.

Sedimentation coefficients of cytoplasmic estradiol and progesterone receptors of human proliferative endometrium and endometrial carcinoma were determined by sucrose gradient centrifugation. In the absence of KCl, receptors from proliferative endometrium sedimented as single bands in the 8 S region and in the presence of 0.3M KCl in the 4 S region of the gradients. Receptors from endometrial carcinoma sedimented in several bands (between 3 and 9 S). When chromatographed on agarose gel comumns, the receptors (from both normal and neoplastic tissue) showed different molecular weights in the presence and absence of KCl (approximately 40,000 and 120,000, respectively). Elution profiles from agarose gel and ion exchange columns, as well as electrophoretic patterns from isoelectric focusing, revealed a similarity between biochemical properties of the receptors from endometrial carcinoma and proliferative endometrium. While the concentration of binding sites for estradiol and progesterone in normal endometrium depended on the day of the cycle, in endometrial carcinoma it depended on the degree of differentiation of the tumor. The binding of estradiol was highest at the beginning of the proliferative phase and declined continuously towards the 14th day of the cycle. In contrast, the concentration of progesterone binding sites was relatively low throughout the proliferative phase. In endometrial carcinoma low binding of estradiol was obtained in well differentiated tumors and high binding (as high as in proliferative endometrium) in undifferentiated tumors. For progesterone the contrary was the case. There was no difference in pH sensitivity between cytoplasmic receptors from normal and neoplastic tissue, optimal binding occurring at pH 7. Dissociation constants (Kd) for estradiol and progesterone depended on the degree of tumor differentiation. Kd values increased for E2 and decreased for P with increasing differentiation of the tumor. Competition studies with various unlabeled steroids revealed no significant difference between the specificity of the receptors from proliverative and neoplastic endometrium.

Binding, Competitive↗