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Biomedical subjects

E Boquoi

Publications and source records attributed to E Boquoi.

At least 19 recordsLinked to original sources
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↗
PubMed1977

[Needle biopsies of sarcomas of the breast: cytomorphology and DNA cytophotometry (author's transl)].

When needle biopsies are done on all palpable changes in the breasts, some sarcomas of the breast can be found. The cytomorphology of this mesenchymal tumor is described and the differential cytology is discussed. In some of our cases the relative content of DNS of the cell nuclei in the smear was determined by quantitative cytophotometry in a Feulgen Stain. It was found that the DNS values of lymphosarcoma and spindle cell stromal sarcoma were within the norm of class 2C to 4C. The DNS content of angiosarcoma and polymorphous stromal sarcomas showed wide variations up to class 8 C. The result is discussed in view of automated cytological diagnosis.

Biopsy, Needle↗
PubMed1977

[The importance of fine needle biopsy in modern breast diagnosis (author's transl)].

860 mammary tumours were clinically, mammographically and cytologically examined. Only thereafter, the histological diagnosis was established following surgical biopsy. There were found 356 malignant and 504 benign processes. The limited reliability of the individual methods is pointed to. As is proved, the diagnostics can be improved by combining the application of all three methods. On the one hand, a larger number of malignoma or malignoma-suspect processes are discovered, on the other hand, the preoperative diagnostics becomes more reliable. If the 3 methods yield similar findings, the diagnostic probability of error is below 1 per cent. Before, the range of indication was clearly outlined, the technique of punction, obtaining and processing of material was discussed, and the complications and limits of the methods were pointed to.

Biopsy, Needle↗
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↗
PubMed1975

Progesterone metabolism in normal human endometrium during the menstrual cycle and in endometrial carcinoma.

Different subcellular fractions (purity checked by electron microscopy and respective marker enzymes) were incubated with 0.1 muCi 14C-progesterone (10 muM) in 0.15 M phosphate buffer at pH 7.4 and 37 C under air for varying periods of time in the presence of NAD(P)H (500 muM). By the preparation of chromic acid oxidation products and acetates, thin-layer chromatography, and crystallisation to constant specific activity, the following metabolites were identified: 20alpha-hydroxypregn-4-en-3-one, 20alpha-hydroxy-5alpha-pregnan-3-one, 20alpha-hydroxy-5beta-pregnan-3-one, 5alpha-pregnane-3,20-dione, and 5beta-pregnane-3,20-dione, indicating the presence of a 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) and 5alpha- and 5beta-reductases. Most of the 20alpha-HSD activity was located in mitochondria (associated mainly with outer membranes) and microsomes. Purified nuclei and cytosol contained 1/6 to 1/18 of the activity of mitochondria and microsomes, respectively. SUBFRACTIONS OF ENDOMETRIAL CELLS ONLY CONTAINED EITHER 5ALPHA- OR 5BETA-REDUCTASE ACTIVITY. 5alpha-reductase activity was mainly associated with microsomes, 5beta-reductase activity was found only in the cytosol. While in normal endometrium specific enzyme activities in subcellular fractions depended on the phase of the cycle, in endometrial carcinoma it depended on the degree of tumour differentiation. The highest values of 5alpha-reductase activity were found in the early proliferative phase. 20alpha-HSD activity was highest in the middle of the secretory phase. The specific activity of the 5alpha-reductase increased with decreasing differentiation of the tumour while the specific activity of the 20alpha-HSD decreased. Kinetic parameters (Km-values, coenzyme requirements and maximum velocities) were determined. The Km-value for progesterone of the 20alpha-HSD in proliferative endometrium was significantly higher than in secretory endometrium, while the Km-values of the 5alpha- and 5beta-reductases were considerably lower during the proliferative than secretory phase.

Cytosol↗
PubMed1975

Studies on 17beta-hydroxysteroid dehydrogenase in human endometrium and endometrial carcinoma I. Subcellular distribution and variations of specific enzyme activity.

Specific activity of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) was measured in subcellular fractions of normal endometrium at different phases of the menstrual cycle, and of endometrial carcinoma at different degrees of differentiation. The purity of fractions was determined by marker enzymes, RNA/DNA ratio or electronmicrographs. Both in normal and neoplastic tissue 17beta-HSD activity was located mainly in mitochrondria and microsomal enzyme is bound tightly to the membranes of the endoplasmic reticulum. While in normal endometrium specific enzyme activity in subcellular fractions depended on the phase of the cycle, in endometrial carcinoma it depended on the degree of differtiation of the tumours. The highest values of 17beta-HSD activity were found in mitochondria and microsomes of early secretory endometrium (factor in mitochondria and microsomes of early secretory endometrium (factor 10 as compared to proliferative endometrium) and in particulate fractions of well differentiated carcinoma (factor 10 to greater than 10 as compared to undifferentiated carcinoma).

Cell Nucleus↗