Biomedical subjects

I Byrjalsen

Publications and source records attributed to I Byrjalsen.

At least 19 recordsLinked to original sources

PubMed2007

Osteoclasts prefer aged bone.

UNLABELLED: We investigated whether the age of the bones endogenously exerts control over the bone resorption ability of the osteoclasts, and found that osteoclasts preferentially develop and resorb bone on aged bone. These findings indicate that the bone matrix itself plays a role in targeted remodeling of aged bones. INTRODUCTION: Osteoclasts resorb aging bone in order to repair damage and maintain the quality of bone. The mechanism behind the targeting of aged bone for remodeling is not clear. We investigated whether bones endogenously possess the ability to control osteoclastic resorption. METHODS: To biochemically distinguish aged and young bones; we measured the ratio between the age-isomerized betaCTX fragment and the non-isomerized alphaCTX fragment. By measurement of TRACP activity, CTX release, number of TRACP positive cells and pit area/pit number, we evaluated osteoclastogenesis as well as osteoclast resorption on aged and young bones. RESULTS: We found that the alphaCTX/betaCTX ratio is 3:1 in young compared to aged bones, and we found that both alpha and betaCTX are released by osteoclasts during resorption. Osteoclastogenesis was augmented on aged compared to young bones, and the difference was enhanced under low serum conditions. We found that mature osteoclasts resorb more on aged than on young bone, despite unchanged adhesion and morphology. CONCLUSIONS: These data indicate that the age of the bone plays an important role in controlling osteoclast-mediated resorption, with significantly higher levels of osteoclast differentiation and resorption on aged bones when compared to young bones.

Acid Phosphatase↗

PubMed2006

Anabolic and catabolic function of chondrocyte ex vivo is reflected by the metabolic processing of type II collagen.

OBJECTIVE: The aim of the present study was to investigate collagen metabolism after anabolic and catabolic stimulation of chondrocytes ex vivo. DESIGN: Metabolic activities in ex vivo bovine cartilage explants were stimulated with insulin-like growth factor I (IGF-I) or a combination of tumor necrosis factor alpha (TNFalpha) and oncostatin M (OSM). Supernatants were assessed for changes in biochemical markers, N-terminal propeptide of type II (PIINP) collagen and fragments of C-telopeptide of type II collagen (CTX-II). Matrix metalloproteinases (MMP) were added to metabolic inactivated cartilage and evaluated by the two biochemical markers for formation or degradation, respectively. Finally, urinary CTX-II and PIINP were evaluated for assessment of type II collagen turnover in patients with rheumatoid arthritis (RA). RESULTS: In the bovine articular cartilage explants, IGF-I induced an increase in PIINP level up to 4.8+/-1.1[ng/ml]/mg cartilage whereas CTX-II remained below 0.1+/-0.1[ng/ml]/mg cartilage. In the catabolic stimulated explants both PIINP and CTX-II were released to the supernatant, reaching concentrations of 9.0+/-1.4 and 9.1+/-2.2[ng/ml]/mg cartilage, respectively. RA patients had significantly lower serum concentrations of PIINP (3.4+/-3.7 ng/ml) compared with those healthy individuals (18.7+/-12.41 ng/ml, P<0.001). In contrast, RA patients had significantly higher urinary CTX-II (0.8+/-0.8 mg/mmol) compared to the healthy controls (0.1+/-0.08 mg/mmol, P=0.004). CONCLUSIONS: This study is the first to demonstrate that precursors and degradation products of type II collagen released into the supernatant can effectively reflect the anabolic and catabolic activities of stimulated cartilage explants.

Animals↗

PubMed2006

Contribution of the advanced glycation end product pentosidine and of maturation of type I collagen to compressive biomechanical properties of human lumbar vertebrae.

Collagen characteristics contribute to bone biomechanical properties. Yet, few studies have analyzed the independent contributions of bone mineral density (BMD) and post-translational modifications of type I collagen to whole bone strength. Thus, the aim of this study was to determine the relative contributions of BMD and both enzymatic and non-enzymatic collagen crosslink concentration to the biomechanical properties of human vertebrae. Nineteen L3 vertebrae were collected after necropsy (age 26-93; 10 males, 9 females). BMD of the vertebral body was measured by DXA, and the vertebrae were compressed to failure to assess the stiffness, failure load and work to fracture. After mechanical testing, the concentration of both enzymatic crosslinks pyridinoline (PYD), and deoxypyridinoline (DPD) as well as, and the non-enzymatic crosslinks pentosidine (PEN) were analyzed in trabecular and cortical bone by reversed-phase HPLC. The extent of aspartic acid isomerization of type I collagen C telopeptide (CTX) was evaluated by ELISA of native (alpha CTX) and isomerized (beta CTX) forms. BMD was significantly positively related with stiffness (R(2) = 0.74; P < 0.0001), failure load (R(2) = 0.69; P < 0.0001) and work to fracture (R(2) = 0.44; P = 0.002). Bivariate regression analysis showed no association between collagen traits and biomechanical properties. However, in a multiple regression model, BMD and trabecular PEN were both significantly associated with failure load and work to fracture (multiple R(2) = 0.83, P = 0.001 and R(2) = 0.67, P = 0.001, respectively). Similarly, BMD and trabecular alpha/beta CTX ratio were both associated with stiffness (multiple R(2) = 0.83, P = 0.015). These findings indicate that post-translational modifications of type I collagen have an impact on skeletal fragility.

Absorptiometry, Photon↗

PubMed2001

Raloxifene and estrogen reduces progression of advanced atherosclerosis--a study in ovariectomized, cholesterol-fed rabbits.

The present study investigated the effect of raloxifene, a selective estrogen receptor modulator (SERM), on aortic atherosclerosis in 80 ovariectomized, cholesterol-fed rabbits with pre-induced atherosclerosis. The animals were fed an atherogenic diet containing 240 mg cholesterol/day for 15 weeks, after this period a baseline control group was sacrificed. Thereafter, oral treatment was initiated with either estradiol 4 mg/day (n=20), raloxifene (210 mg/day) or placebo (n=20). In the treatment period of 39 weeks, the dietary cholesterol content was reduced to 80 mg cholesterol/day. Postmortem evaluation showed a significantly increased uterine weight induced by estradiol treatment (10.3+/-1.2 g), whereas raloxifene intervention caused a decreased uterus weight (1.21+/-0.1 g) when compared to placebo (2.48+/-0.47 g). Throughout the study, serum lipids increased in all groups to levels seen in very high risk humans. After 58 weeks the cholesterol content in the aorta was 3.18+/-0.54 micromol/cm(2) (38% reduction) in the estradiol group, 3.66+/-0.52 micromol/cm(2) (29% reduction) in the raloxifene group and 5.12+/-0.60 micromol/cm(2) in the placebo group. Analyses of the aortic cholesterol content corrected for time-averaged serum cholesterol revealed that both estradiol and raloxifene therapy significantly reduced the progression of atherosclerosis (P<0.01 for both) as compared to placebo.

Animals↗

PubMed2000

Raloxifene reduces atherosclerosis: studies of optimized raloxifene doses in ovariectomized, cholesterol-fed rabbits.

OBJECTIVE: We have previously shown that raloxifene, a selective oestrogen receptor modulator, 35 mg/day inhibits atherosclerosis in ovariectomized, cholesterol-fed rabbits. This effect was only partial as compared to 17beta-oestradiol 4 mg/day; however, plasma raloxifene concentrations were low relative to those obtained in raloxifene-treated women. We therefore investigate the effects of raloxifene at higher doses. DESIGN: The study on atherosclerosis in ovariectomized, cholesterol-fed rabbits (n = 80) compared raloxifene 70 mg/day and 210 mg/day to 17beta-oestradiol 4 mg/day and placebo. RESULTS: After 48 weeks of therapy, the aortic cholesterol content in the 70 mg/day and 210 mg/day raloxifene treatment groups were 471 +/- 56 nmol/mg protein and 456 +/- 56 nmol/mg protein, respectively. This was significantly less than in the placebo group (654 +/- 69 nmol/mg protein; P < 0.05). In the oestrogen-treated group, the aortic cholesterol content was 357 +/- 62 nmol/mg protein (P < 0.01 as compared to placebo). Differences in serum lipids between the treatment groups could only partly explain the effect on aortic cholesterol content, indicating that additional anti-atherogenic mechanisms may contribute to the decrease in aortic atherosclerosis. This anti-atherosclerotic activity of raloxifene was observed at plasma concentrations comparable to those in postmenopausal women during raloxifene treatment. CONCLUSIONS: We conclude that clinically relevant raloxifene treatment inhibits aortic atherosclerosis in ovariectomized, cholesterol-fed rabbits.

Analysis of Variance↗

PubMed2000

Low doses of estradiol in combination with gestodene to prevent early postmenopausal bone loss.

OBJECTIVE: Our purpose was to study combinations of estradiol and gestodene for prevention of bone loss in early postmenopausal women. STUDY DESIGN: We randomly assigned 278 healthy, early postmenopausal women to receive either 2 mg 17beta-estradiol sequentially combined with 25 microg gestodene (group 2/25s), 2 mg estradiol sequentially combined with 50 microg gestodene (group 2/50s), 1 mg estradiol sequentially combined with 25 microg gestodene (group 1/25s), 1 mg estradiol continuously combined with 25 mg gestodene (group 1/25c), or placebo. RESULTS: After 3 years the changes in bone mineral density of the spine were as follows (mean +/- SEM): group 2/25s, 7. 41% +/- 0.72%; group 2/50s, 8.53% +/- 0.90%; group 1.25s, 6.67% +/- 0.88%; group 1/25c, 4.44% +/- 0.59%; and placebo group, -2.03% +/- 0. 64%. The changes in bone mineral density were mirrored in the biochemical bone markers. The average responses for the urinary C-terminal telopeptide fragments of type I collagen corrected for creatinine excretion were as follows (mean of baseline +/- SEM): group 2/25s, -68.8% +/- 0.03%; group 2/50s, -72.8% +/- 0.02%; group 1/25s, -60.7% +/- 0.03%; group 1/25c, -52.28% +/- 0.04%; and placebo group, 6.5% +/- 0.09%. Beneficial lipid effects were found in all active groups. The decreases in low-density lipoprotein were as follows (mean +/- SEM): group 2/25s, -13.7% +/- 3.0%; group 2/50s, -14.6% +/- 3.2%; group 1/25s, -9.28% +/- 2.2%; group 1/25c, -9.92% +/- 2.4%; and placebo group, 1.53% +/- 1.9%. CONCLUSION: These results demonstrate that estradiol therapy with 1 mg estradiol is fully protective against early postmenopausal bone loss.

Bone Density↗

PubMed2000

Piperazine oestrone sulphate and interrupted norethisterone: effects on the postmenopausal endometrium.

OBJECTIVE: To assess the effects on the postmenopausal endometrium of two doses of oral piperazine oestrone sulphate and interrupted norethisterone in comparison with a continuously combined regimen and placebo. DESIGN: A prospective randomised trial. PARTICIPANTS: Two hundred healthy postmenopausal women. METHODS: Random assignment to two years of treatment with alternating three-day cycles of 1.5 mg piperazine oestrone sulphate and 1.5 mg piperazine oestrone sulphate + 0.7 mg norethisterone (highEP), or alternating three-day cycles of 0.75 mg piperazine oestrone sulphate and 0.75 mg piperazine oestrone sulphate + 0.35 mg norethisterone (lowEP), or 2 mg 17 beta-oestradiol continuously combined with 1 mg norethisterone acetate (E2+NETA), or placebo. MAIN OUTCOME MEASURES: Effect of treatment on endometrial histology, endometrial thickness, occurrence of uterine bleeding, endometrial oestrogen and progesterone receptor content, endometrial isocitrate dehydrogenase activity, and serum placental protein 14. RESULTS: The incidence of bleeding declined with time. In the second treatment year, the women receiving lowEP reported on average 7.3 days of bleeding, highEP 16.7 days, and E2+NETA 11.2 days. Histological assessment of endometrial biopsies revealed an atrophic or slightly secretory endometrium. Serum placental protein 14 increased slightly, but was statistically highly significant, during treatment, but no cyclical variation was observed. Endometrial isocitrate dehydrogenase was low in all three hormone groups and the same low level of endometrial oestrogen receptor and progesterone receptor was found comparable to the level in the placebo group. CONCLUSIONS: Histological and biochemical assessment of the endometrium showed that interrupted hormone replacement therapy induced the same pattern in endometrial parameters as continuous combined hormone replacement therapy.

Administration, Oral↗

PubMed2000

Piperazine oestrone sulphate and interrupted norethisterone in postmenopausal women: effects on bone mass, lipoprotein metabolism, climacteric symptoms, and adverse effects.

OBJECTIVE: To compare the effects of two doses of piperazine oestrone sulphate combined with interrupted norethisterone, with that of oestradiol continuously combined with norethisterone acetate, and with placebo, in postmenopausal women. DESIGN: A prospective randomised trial. PARTICIPANTS: Two hundred postmenopausal women. SETTING: Monocentre study with expertise in osteoporosis. METHODS: The participants were randomly assigned to two years of treatment with alternating three-day cycles of 1.5 mg of piperazine oestrone sulphate plus 0.7 mg of norethisterone (highEP), or alternating three-day cycles of 0.75 mg of piperaine oestrone sulphate plus 0.35 mg of norethisterone (lowEP), or 2 mg of 17beta-oestradiol continuously combined with 1 mg of norethisterone acetate (E2+NETA), or placebo. MAIN OUTCOME MEASURES: Change in bone mineral density, lipoprotein metabolism, climacteric symptoms, and adverse effects. RESULTS: One hundred and twenty-one women completed the study. Spinal bone mineral density was increased about 9% over two years by E2+NETA, about 6% by highEP, 4% by lowEP, but remained unchanged in the placebo group. The same pattern was seen in the hip and forearm. All hormone regimens decreased markers of bone turnover and alleviated climacteric symptoms. Serum lipoproteins decreased by about 10% in all hormone groups. CONCLUSIONS: All hormone regimens studied prevented bone loss completely and lowered serum lipids.

Aged↗

PubMed1999

Natural androgens inhibit male atherosclerosis: a study in castrated, cholesterol-fed rabbits.

The effect of natural androgens on serum lipids and atherosclerosis is controversial. We therefore studied this important issue prospectively in an animal model of atherosclerosis. Eighty male rabbits were randomized to bilateral castration, and 20 animals were sham operated. The castrated rabbits were randomized to 500 mg oral dehydroepiandrosterone (DHEA) daily, 80 mg oral testosterone undecanoate (TU) daily, or 25-mg intramuscular injection of testosterone enanthate (TE) twice weekly, whereas the fourth castrated group (placebo) and the sham-operated rabbits did not receive any hormones. All animals were fed a cholesterol-rich diet during the 30-week treatment period. Average serum lipids and atherogenic lipoproteins were higher in the placebo group than in the other groups (ANOVA, P<0.0001). Aortic atherosclerosis, as evaluated by the cholesterol content (nmol/mg protein), was also highest in the placebo group (308+/-39) and lowest in the TE group (61+/-12), but was intermediate in the DHEA (155+/-30), TU (191+/-43), and sham operation (162+/-29) groups (ANOVA, P<0.0001). ANCOVA indicated that the androgen effect on aortic atherosclerosis was only in part explained by the changes in lipoproteins. Aortic estrogen receptor contents were significantly lower in the androgen-treated groups than in the control groups, whereas there was no difference in aortic androgen receptor contents between groups. Natural androgens inhibit aortic atherosclerosis in castrated male rabbits only partly through a lipid-mediated effect.

Adrenal Glands↗

PubMed1999

Progestational effects of combinations of gestodene on the postmenopausal endometrium during hormone replacement therapy.

OBJECTIVE: The aim of the study was to assess the dose-response effects on the postmenopausal endometrium of 3 sequential combined hormone replacement regimens and 1 continuous combined hormone replacement regimen of estradiol and gestodene. STUDY DESIGN: In this 2-year double-blind, placebo-controlled study, 278 healthy postmenopausal women received either 2 mg estradiol sequentially combined with 50 microg or 25 microg gestodene, 1 mg estradiol sequentially or continuously combined with 25 microg gestodene, or placebo. RESULTS: All 4 hormone treatment regimens produced a safe endometrial histologic appearance. The regimens that were based on the lower dose of 1 mg estradiol was associated with less uterine bleeding than were those that were based on 2 mg estradiol. For sequentially opposing the 2 mg dose of estradiol, the dose of 25 microg gestodene was less efficient in producing secretory activity than was the dose of 50 microg gestodene. The measurement of placental protein 14 in serum reflected the secretory transformation of the endometrial buildup. CONCLUSION: The reduction in bleeding episodes associated with regimens with lower estradiol doses may lead to improved long-term therapy compliance by menopausal women. The potency of progestogens can be assessed by measuring the serum concentration of placental protein 14.

Dose-Response Relationship, Drug↗

PubMed1999

Two-dimensional gel analysis of human endometrial proteins: characterization of proteins with increased expression in hyperplasia and adenocarcinoma.

In the search for new markers of human endometrial hyperplasia and adenocarcinoma the method of quantitative two-dimensional gel electrophoresis was applied to study the protein expression profiles of metabolically [(35)S]-methionine-labelled proteins of endometrial explants. Approximately 1700 protein spots were resolved by the two-dimensional gel electrophoresis, and the expression pattern of each of these proteins was assessed for increased expression during hyperplasia or adenocarcinoma. In total, six protein spots showed increased expression in hyperplasia, 19 in carcinoma, and eight in both hyperplasia and carcinoma. Twelve of these 33 differentially expressed proteins were identified by peptide mass mapping combined with sequence database searching. Among the identified proteins were proteins involved in cellular transport and chaperoning, i.e. heat shock protein 27 kDa protein, heat shock 70 kDa protein, heat shock cognate 71 kDa protein, and serotransferrin. Other identified proteins were: regulatory chain protein of cAMP-dependent protein kinase, prohibitin, and heterogeneous nuclear ribonucleoprotein A2/B1. Finally we identified proteins associated with the cytoskeleton, vimentin and tropomyosin isoform 3, and the glycolytic pathway, alpha enolase, and phosphoglycerate kinase. The remaining unidentified proteins were either not contained in the database and must be assumed to be novel proteins, or were present in too low amounts to allow characterization.

Adenocarcinoma↗

PubMed1998

The collagenolytic activity of cathepsin K is unique among mammalian proteinases.

Type I collagen fibers account for 90% of the organic matrix of bone. The degradation of this collagen is a major event during bone resorption, but its mechanism is unknown. A series of data obtained in biological models strongly suggests that the recently discovered cysteine proteinase cathepsin K plays a key role in bone resorption. Little is known, however, about the actual action of cathepsin K on type I collagen. Here, we show that the activity of cathepsin K alone is sufficient to dissolve completely insoluble collagen of adult human cortical bone. We found that the collagenolytic activity of cathepsin K is directed both outside the helical region of the molecule, i.e. the typical activity of cysteine proteinases, and at various sites inside the helical region, hitherto believed to resist all mammalian proteinases but the collagenases of the matrix metalloproteinase family and the neutrophil elastase. This property of cathepsin K is unique among mammalian proteinases and is reminiscent of bacterial collagenases. It is likely to be responsible for the key role of cathepsin K in bone resorption.

Adult↗

PubMed1997

Raloxifene inhibits aortic accumulation of cholesterol in ovariectomized, cholesterol-fed rabbits.

BACKGROUND: The beneficial effect of long-term hormone replacement therapy in terms of a decreased risk of cardiovascular disease is now generally accepted. Raloxifene, a selective estrogen receptor modulator, has demonstrated hypolipidemic properties while leaving the endometrium unstimulated. METHODS AND RESULTS: For our study of the effects of raloxifene on atherosclerosis, 75 rabbits were ovariectomized and treated with either raloxifene, 17beta-estradiol, or placebo; 25 rabbits were sham operated and treated with placebo. After 45 weeks, the raloxifene group had two thirds of the aortic atherosclerosis, as evaluated by the cholesterol content of the proximal inner part of the aorta, found in the placebo group (placebo, 577+/-55.1 nmol/mg protein; raloxifene, 397+/-53.6 nmol/mg protein; P<.05); the estrogen group had one third of the aortic atherosclerosis in the placebo group (estrogen, 177+/-32.1 nmol/mg protein; P<.001). The sham-operated group (473+/-59.6 nmol/mg protein) was not significantly different from placebo. These effects were only partly explained by the changes in serum lipids and lipoproteins, and treatment with both estrogen and raloxifene independently predicted the response in aorta cholesterol. Because plasma levels of total raloxifene were low relative to clinical values in postmenopausal women, dose-response data for raloxifene are required. CONCLUSIONS: Our findings indicate that raloxifene hydrochloride has a potentially important antiatherogenic effect, analogous to that observed with estrogen in this model.

Animals↗

PubMed1997

Enzyme immunoassay for measuring 25-hydroxyvitamin D3 in serum.

We developed a rapid, competitive enzyme immunoassay (EIA) for measuring 25-hydroxyvitamin D3 [25(OH)D3] in serum. The EIA was based upon 25(OH)D3-3-hemisuccinate covalently coupled to secondary amino groups grafted onto the polystyrene surface of microtiter wells. Optimal coupling conditions were established, and we found that inclusion of 40 mumol/L chloramine T, an agent not previously described for use in coupling to these plates, resulted in both more reproducible coupling as well as more than a twofold increase in the coupling efficiency. Before EIA, 25(OH)D3 was extracted from the serum samples by acetonitrile, and the redissolved extract was incubated with polyclonal rabbit antibody raised against 1,25-dihydroxyvitamin D3-3-hemisuccinate conjugated to bovine serum albumin. Peroxidase-labeled antibody raised in goat against rabbit immunoglobulins was used for detection. The detection limit of the EIA was 4.4 micrograms/L; recovery 102%; on-plate CV 11%; within-run CV including extraction 12%, and between-run CV 15%. There was no clinically important cross-reactivity with other vitamin D metabolites, and results obtained by the EIA were compared with results obtained by a previously described RIA.

Adult↗

PubMed1995

Two-dimensional gel analysis of human endometrial proteins: cyclic changes in the expression of specific proteins during the normal menstrual cycle.

High resolution two-dimensional (2-D) gel electrophoresis was used to compare the patterns of [35S]methionine-labelled cellular proteins in endometrial tissue from healthy, normally menstruating women. Samples of endometrial tissue were incubated with [35S]methionine for 20 h, and total cell lysates were processed for 2-D gel electrophoresis. Using this technique it was possible to study proteins with iso-electric points (pI) ranging from 3.5 to 11 and relative molecular weights (M(r)) ranging from 10,000 to 300,000 Da. The fluorograms were compared by computer-aided analysis whereby a total of 1095 [35S]-labelled proteins were resolved on the iso-electric focusing gels (IEF, pI 3.5-7) and 488 on the non-equilibrium pH gradient electrophoresis (NEPHGE) gels (pI 6.5-11). Of the proteins on the IEF gels, 125 showed differential expression during the menstrual cycle. Of these, 36 were maximally expressed in proliferative phase endometrium, 26 in the interval phase and 63 in secretory and/or late secretory phase endometrium. Correspondingly, on the NEPHGE gels a total of 61 proteins exhibited cyclical variation, of which 30 were more prominent in proliferative phase, 13 in interval phase and 18 in secretory phase endometrium. This study shows that 2-D gel electrophoresis is eminently suited to the identification of proteins whose expression varies in a cyclical manner during the menstrual cycle. Further investigations should be carried out to isolate and characterize these proteins with the aim of establishing useful markers for specific endometrial phases of the menstrual cycle.

Adult↗

PubMed1995

Human endometrial proteins with cyclic changes in the expression during the normal menstrual cycle: characterization by protein sequence analysis.

Endometrial proteins showing cyclic expression during the normal menstrual cycle were localized on two-dimensional (2-D) electrophoresis gels separating proteins with isoelectric points (pl) ranging from 3.5 to 7 and relative molecular weights ranging from 10 to 300 kDa. Menstrual cycle-related proteins were excised from several 2-D gels, concentrated by one-dimensional (1-D) sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis, and cleaved in situ by trypsin. The tryptic fragments were extracted and separated by reverse phase high performance liquid chromatography (RP-HPLC). Finally, the partial amino-terminal amino acid sequence of selected tryptic fragments were determined for each protein. We aimed at characterizing the 21 menstrual cycle-related proteins that were visible on silver-stained 2-D electrophoresis gels. Of the proteins being maximally synthesized in the proliferative phase endometrium, we identified proteins associated mainly with the cytoskeleton: vimentins, keratin, tropomyosin and tubulin, but also proteins such as proliferating cell nuclear antigen and beta-galactoside binding lectin. The partial amino acid sequences for another two proteins did not match any protein sequence in the Protein Identification Resource (PIR) and Swissprot databases. In the group of proteins having maximal synthesis in the secretory phase endometrium, we identified creatine kinase chain B and an isocitrate dehydrogenase-homologous protein, both of which are involved in energy metabolism. However, we also identified the annexin IV precursor, the 14-3-3 protein homologue also called stratifin or the epithelial cell marker protein 1 and the 21K tumour protein. Finally, four of the proteins were present in too low amounts to allow characterization. Interestingly, most of the identified proteins have not previously been described as having a menstrual cycle-related synthesis in the human endometrium. It may be considered that the concentration of some of the cycle-related proteins may be used in clinical situations to reflect specific endometrial phases.

Amino Acid Sequence↗

PubMed1993

Role of cigarette smoking on the postmenopausal endometrium during sequential estrogen and progestogen therapy.

OBJECTIVE: To study the effect of cigarette smoking on the endometrial response to sequentially combined hormone replacement therapy. METHODS: Healthy, early postmenopausal women were randomly assigned to three treatment groups: estradiol (E2) sequentially combined with 75 micrograms of levonorgestrel (19), or 150 micrograms of desogestrel (20), or 10 mg of medroxyprogesterone acetate (18). After 2 years of therapy, the hormone effects on the endometrium were assessed by endometrial histology; effects were also analyzed on biochemical markers of secretion, specifically, secretory endometrial protein (placental protein 14) in serum, and E2 dehydrogenase and isocitrate dehydrogenase in endometrial tissue. Information on smoking habits was elicited by questionnaire. RESULTS: Smokers numbered relatively more women with an atrophic endometrium (50 versus 22%) and proportionally fewer with secretory endometrium (50 versus 78%) (P < .05). The level of serum placental protein 14 was correspondingly almost halved in the smokers (P < .001). The influence of smoking was in part caused by a reduced level of serum E2, but primarily by a non-E2-mediated effect. The E2 effect accounted for 38% of the decrease in serum placental protein 14, and the non-E2-mediated smoking effect for 62%. Endometrial E2 and isocitrate dehydrogenase tended to be lower in smokers, but not after adjustment for the reduced serum E2 level. CONCLUSION: We suggest that smokers may benefit from a hormone combination with a higher dose of E2, even higher than expected as seen from the measurement of serum E2.

Desogestrel↗

PubMed1992

Secretory endometrial protein PP14 in serum from post-menopausal women receiving continuous combined oestradiol-cyproterone acetate: correlation with serum hormone concentrations and bleeding patterns.

The secretory endometrial protein PP14 was measured in serum from 49 healthy, early post-menopausal women receiving continuous combined oestradiol valerate/cyproterone acetate (2 mg E2V + 1 mg CPA daily) or placebo over a period of 2 years. In the hormone group, serum PP14 increased from 2.1 micrograms/l to a maximum of 8.1 micrograms/l after 1 month of treatment, then fell after 3 months to 3.8 micrograms/l and remained at that level for the rest of the 2-year period. After the first month, the occurrence of uterine bleeding was associated with significantly increased serum PP14 levels. Bleeding was not correlated with the serum concentration of 17 beta-oestradiol (E2) or CPA, or the CPA/E2 ratio. Serum PP14 was significantly dependent on the serum concentration of E2, but not on that of CPA. The present data confirm that serum PP14 levels reflect the secretory phase of the endometrium and that bleeding during continuous combined hormone replacement therapy is probably caused by a sub-optimal hormonal balance.

Androgen Antagonists↗