Metabolism of tibolone and its metabolites in uterine and vaginal tissue of rat and human origin.

In postmenopausal women, tibolone shows clear tissue differences in its stimulatory effects on the vagina and uterus. In rats, however, it has stimulatory effects on both tissues, with a different, more estrogenic, effect on the uterus than in humans. This may be due to differences in local metabolism. Therefore, in the present study, the metabolism of tibolone was analyzed in incubations of uterine and vaginal tissue from postmenopausal women and ovariectomized rats using radiolabeled tibolone in order to understand the tissue- and species-specific metabolism. In the rat, tibolone (50 nM) was mainly 3alpha-reduced to the estrogenic 3alpha-OH-tibolone in the uterus and vagina. The 3beta-OH tibolone can be isomerized to 3alpha-OH-tibolone with tibolone as intermediate. In contrast, in the same tissues from postmenopausal women, the progestagenic Delta4-isomer and estrogenic 3beta-OH-tibolone were the major metabolites of tibolone. The formation of the Delta4-isomer was higher in uterine tissue. The 3beta-hydroxysteroid dehydrogenase (HSD) inhibitor epostane had no effect on tibolone metabolism in human uterine and vaginal tissue microsomes and HEK293 cells expressing the human 3beta-HSD types 1 and 2 isoforms did not metabolize tibolone. Moreover, the 3beta-reduction of tibolone to 3beta-OH-tibolone was NADPH dependent, while the isomerization of tibolone to the Delta4-isomer did not require a cofactor. It was therefore concluded that human 3beta-HSD isoforms are not involved in the metabolism of tibolone, and that the 3beta-reduction and the Delta5-10 to Delta4 isomerization may be catalyzed by different enzymes. In conclusion, we showed that, in hormone therapy target tissues of the rat as compared with the human, different metabolic pathways for tibolone exist and therefore result in metabolites with different pharmacological properties. The rat is therefore a poor model to predict the effects of tibolone on the uterus in postmenopausal women.

Hypocorticism and interrenal hyperplasia are not directly related to masculinization in XX mas(-1)/mas(-1) carp, Cyprinus carpio.

This study reports on a homozygous XX male strain of common carp (E5), which fail to mount a normal cortisol stress response. Earlier classical genetic analysis had indicated that masculinization of E5 fish was caused by a putative recessive mutation (mas(-1)/mas(-1)). Hypocorticism in E5 fish was studied to investigate if it was related to masculinization. Head-kidney tissues isolated from E5 fish showed a low cortisol-producing capacity in vitro, and also demonstrated a reduced sensitivity to stimulation with ACTH, when compared with an isogenic XY male carp strain (STD). There was no strain difference in androgen production by head-kidney tissues in vitro. E5 fish exhibited significant hyperplasia of the interrenal tissue (adrenal homologue of teleost fish) located in the head-kidney. Conversion of pregnenolone was significantly lower in E5 head-kidney homogenates, compared to STD homogenates, however, no strain difference was found in the conversion of 17alpha-hydroxyprogesterone into cortisol. Gonad homogenates incubated with pregnenolone showed no strain difference in conversion to corticosteroids and androgens. Results indicate that the interrenal hyperplasia and hypocorticism in this strain of carp may be due to a dysfunction of the 17alpha-hydroxylase activity of the enzyme P450c17 in the interrenal, but that this defect may not be the primary factor resulting in masculinization of these XX genotypes.

The impact of hospital discharge on inappropriate hospital stay.

Appropriate hospital stay should be effective, efficient and tailored to patient needs. Previous studies have found that on average 20 per cent of hospital stay is inappropriate. Within obstetrics, inappropriate hospital stay consists mostly of delays in hospital discharge. The specific goals of this study were to reduce inappropriate hospital stay by fine-tuning patient logistics, increasing efficiency and providing more comfortable surroundings. New policies using strict discharge criteria were implemented. Total inappropriate hospital stay decreased from 13.3 to 7.2 per cent. The delay in discharge procedures halved. P-charts showed a decrease in inappropriate hospital stay, indicating the current process to be stable. Concludes that a significant reduction in inappropriate hospital stay was found following the implementation of innovative hospital discharge policies, indicating greater efficiency and accessibility of hospital services.

Appropriate length of extended day care.

Extended day care (EDC) is a one-day admission spending one night in hospital. Many EDC patients do not need hospital care over night, so probably they could be transferred to a day surgery setting, resulting in decreased costs and increased efficiency. The objectives of the study were to assess the appropriate length of extended day care (ALED) and a possible transfer to day surgery. ALED was defined as the time between the start of the surgical procedure and the final moment appropriate hospital care was provided. About 80 per cent of the patients could possibly have been treated in day surgery. The other patients could not be transferred, because of a prolonged ALED. With the implementation of new policies on admission to and discharge from the hospital and the use of altered types of operation room scheduling or patient logistics the transfer of most EDC patients to day surgery would be possible.

Identifying inappropriate hospital stay in patients with venous thromboembolism.

Background: Traditionally, venous thromboembolism has been treated in a hospital setting. Nowadays, low molecular weight heparin (LMWH) preparations allow most deep venous thrombosis (DVT) patients to benefit from home therapy. The objective of this study was to evaluate whether the previous treatment of deep venous thrombosis in a hospital setting was appropriate in the context of modern opinion, using the Dutch Appropriateness Evaluation Protocol (DAEP). If so, the DAEP could be used to assess the appropriateness of the present hospital stay of other patient groups. Methods: A retrospective study of patients treated from 1995 to 1998 for DVT or for pulmonary embolism (PE), before the implementation of ambulatory treatment, was conducted that assessed the appropriateness of the patient's hospital stay using the DAEP. Results: Only 27.1% of the treatments for DVT were found to be appropriate in a hospital setting and related to specific hospital care. Inappropriate stay was mostly related to delays in hospital and discharge procedures. Of the patients with PE, 50.2% needed a hospital stay. This proportion was statistically significantly higher than in DVT patients (p<0.001). The extent of the DVT was not related to the length of bed rest prescribed. Conclusions: The DAEP was able to identify inappropriate hospital stay in the past within the DVT patient group. Further exploration of the potential of the DAEP to identify patient groups who could be treated at home is warranted.

Predictors of inappropriate hospital stay: a clinical case study.

OBJECTIVE: To assess the reasons for inappropriate patient stay (IPS) and to identify possible predictors of this inappropriate stay. DESIGN: The reasons for IPS were analyzed in a cross-sectional survey at two surgical one gynecologic and one obstetric ward, using a sample of 610 days of hospital stay by means of the Dutch Appropriateness Evaluation Protocol. SETTING: The study was conducted at the University Hospital Maastricht, a 715-bed hospital with a regional and teaching function, located in the southern part of The Netherlands. RESULTS: Results indicate that > 20% of the hospital stay was inappropriate. The reasons for IPS were statistically significantly related to the patients' age, the availability of home care and medical specialty. In a predictive model, only the specialty proved to be a predictor of IPS. Most of the IPS occurred during the first days of hospital stay and the days before the patient's discharge. CONCLUSION: A substantial proportion of hospital stay was found to be inappropriate, due to hospital procedures and the inability to refer patients to other care facilities or care providers. Analysis of the causes of IPS provided useful data for improvement actions. Efficient use of hospital resources should be promoted by reducing the delay in interventions and discharge procedures.

Sex steroids and their involvement in the cortisol-induced inhibition of pubertal development in male common carp, Cyprinus carpio L.

The onset and regulation of puberty is determined by functional development of the brain-pituitary-gonad (BPG) axis. Sex steroids produced in the gonads play an important role in the onset of puberty. Stress interferes with reproduction and the functioning of the BPG axis, and cortisol has frequently been indicated as a major factor mediating the suppressive effect of stress on reproduction. Prolonged elevated cortisol levels, implicated in stress adaptation, inhibited pubertal development in male common carp (Cyprinus carpio). Cortisol treatment caused a retardation of pubertal testis development and reduced the LH pituitary content and the salmon GnRHa-stimulated LH secretion in vitro. A reduced synthesis of androgens also was observed. These findings suggest that the cortisol-induced inhibition of testicular development and the maturation of pituitary gonadotrophs are mediated by an effect on testicular androgen secretion. In this study, we combined cortisol treatment with a replacement of the testicular steroid hormones (testosterone and 11-oxygenated androgens) to investigate the role of these steroids in the cortisol-induced suppression of pubertal development. The effect of cortisol on spermatogenesis was independent of 11-ketotestosterone, whereas the effect on the pituitary was an indirect one, involving the testicular secretion of testosterone.

To stay or not to stay. The assessment of appropriate hospital stay: a Dutch report.

OBJECTIVE: To adjust the adult-medical Appropriateness Evaluation Protocol (AEP) into a valid and reliable instrument for use in the Dutch health care system, to assess the appropriateness of hospital stay and to identify the causes of inappropriateness. DESIGN: The appropriateness of hospital stay was assessed in a cross-sectional survey on a sample of over 4500 days of stay using a modified, Dutch version of the Appropriateness Evaluation Protocol (D-AEP). SETTING: The appropriateness of stay was assessed in five internal and surgical departments for adult acute care in the University Hospital of Maastricht, a 700-bed hospital with a teaching and regional function, located in the southern part of the Netherlands. RESULTS: The results showed that over 20% of the hospital stay was inappropriate. Half of the inappropriate hospital stay (45.1%) was due to (internal) hospital procedures. The D-AEP proved to be valid (kappa = 0.76; 95% confidence interval (95% CI) 0.68-0.84), reliable (kappa = 0.84; 95% CI 0.75-0.93) and easy to use. CONCLUSION: A substantial proportion of hospital stay was found to be inappropriate, due to hospital procedures and the inability to refer patients to other care facilities or care providers. The D-AEP can be used for monitoring the appropriate hospital stay and in detecting possible causes of inappropriate stay. Analysis of the causes of inappropriate hospital stay provided useful data for improvement actions.

Cortisol affects testicular development in male common carp, Cyprinus carpio L., but not via an effect on LH secretion.

Previous work showed that prolonged elevated cortisol levels, implicated in the stress adaptation, inhibits testicular pubertal development in male common carp, as well as an impairment of the synthesis of the 11-oxygenated androgens. This may be a direct effect of cortisol on the testis or via the gonadotropin secretion by the pituitary. The aim of the present study was to investigate whether cortisol has an effect on pituitary LH secretion. Juvenile common carp were fed with cortisol containing food pellets. Elevated cortisol levels blocked the increase in testosterone levels and pituitary LH content, but induced higher plasma LH levels at the end of puberty. The in vitro LH release capacity was correlated to the pituitary LH content. At the final stage of pubertal development, when a significant difference in pituitary LH content was observed, sGnRHa-induced LH release was also decreased. Testosterone has been shown to induce development of pituitary gonadotrophs, leading to an increase in LH content and GnRH-inducible LH release, but a decrease in plasma LH levels. We observed decreased plasma testosterone levels as a consequence of prolonged cortisol treatment. It is hypothesised that cortisol inhibits the testicular testosterone secretion and thereby, prevents LH storage. In vitro, this leads to a reduced GnRH-inducible LH release, but in vivo to increased LH plasma levels. It is very unlikely that the impaired testicular development is due to an effect of cortisol on LH secretion.

Metabolism of norethisterone and norethisterone derivatives in rat uterus, vagina, and aorta.

The 19-nor-progestogen norethisterone is used as a progestogen component in contraceptives and in continuous- and sequential combined hormone replacement therapy (HRT) in postmenopausal women. Metabolism of norethisterone in HRT target tissues may play a role in its biological response. The aim of this study was to investigate which steroid-metabolizing enzymes are present in rat uterus, vagina, and aorta, three HRT target tissues. Next, the ability of the tissues to metabolize norethisterone was assessed. Furthermore, to investigate the effect of substituents at the 7- and 11-position, the metabolism of Org OM38 (7alpha-methyl-norethisterone), Org 4060 (11beta-ethyl-norethisterone), and Org 34694 (7alpha-methyl,11-ethylidene-norethisterone) was studied. Using radiolabeled progesterone, the presence of 20alpha-hydroxysteroid dehydrogenase, 5alpha-reductase, and 3alpha-hydroxysteroid dehydrogenase activity could be demonstrated in uterus, vagina, and to a lesser extent in aorta. The combined action of the latter two enzyme activities resulted in 3alpha-OH,5alpha-H-norethisterone as the major metabolite of radiolabeled norethisterone in uterus (26.9%), vagina (37.1%), and aorta (1.4%). The norethisterone derivatives, however, were metabolized to a much lesser extent (1.0-7.6%). No formation of 5alpha-reduced forms of Org 4060, Org OM38, or Org 34694 was found, while formation of minor amounts of 3alpha-OH-Org 4060 and 3alpha-OH-Org OM38 could be demonstrated in both uterus, vagina, and aorta. These findings confirm the role of 5alpha-reductase as a rate-limiting step in the metabolism of norethisterone derivatives and show important inhibitory effects of substituents at the 7alpha- and 11-position of the steroid skeleton on 5alpha-reduction.

Long-term cortisol treatment inhibits pubertal development in male common carp, Cyprinus carpio L.

The onset and regulation of puberty is determined by functional development of the brain-pituitary-gonad (BPG) axis. Stress has been shown to interfere with reproduction and the functioning of the BPG axis. The response to chronic and severe stress may require much energy and force the organism to make adaptive choices. Energy that is normally available for processes like growth, immune response, or reproduction will be channeled into restoration of the disturbed homeostasis. Cortisol plays a key role in the homeostatic adaptation during or after stress. In the present study, immature common carp were fed with cortisol-containing food pellets covering the pubertal period. We showed that cortisol caused an inhibition of pubertal development, by affecting directly or indirectly all components of the BPG axis. The salmon GnRH content of the brain was decreased. Luteinizing hormone- and FSH-encoding mRNA levels in the pituitary and LH plasma levels were diminished by long-term cortisol treatment, as was the testicular androgen secretion. Testicular development, reflected by gonadosomatic index and the first wave of spermatogenesis, was retarded.

Metabolism of estradiol, ethynylestradiol, and moxestrol in rat uterus, vagina, and aorta: influence of sex steroid treatment.

Estrogen replacement therapy for postmenopausal women consists of an estrogenic and a progestagenic compound. The treatment has a positive estrogenic effect on bone, the cardiovascular system, and vagina but is dependent of the estrogen-progestagen balance in uterus to prevent unwanted proliferation. We were interested in the influence of estrogens and progestagens on estrogen metabolism in target tissues of estrogen replacement therapy. Therefore, we studied the metabolism of estradiol, 17alpha-ethynylestradiol, and moxestrol (11beta-methoxy-17alpha-ethynylestradiol) in rat uterus, vagina, and aorta. In uterus and vagina, estradiol was converted to estrone, estradiol-3-glucuronide, and estrone-3-glucuronide. These metabolites demonstrate the presence of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) and UDP-glucuronosyl transferase (UDP-GT) in uterus and vagina. We found that the conversion of estradiol by 17beta-HSD in uterus was increased in animals treated with estradiol or with a combination of estradiol and progesterone. The conversion of estradiol in uterus by UDP-GT was estradiol-induced and in contrast, progesterone-suppressed. In the vagina, steroid hormone treatment had no effect on estradiol conversion by 17beta-HSD or UDP-GT. Ethynylestradiol was glucuronidated only, and this was not affected by steroid treatment. Moxestrol was not converted in any of the three organs that were studied, indicating that the 11beta-methoxy substituent renders it a poor substrate for glucuronidation. Overall, the estrogen metabolism, and its regulation by sex steroids, in rat uterus is different compared with human uterus. Therefore, the rat may not be the best-suited model to investigate uterine effects of estradiol-progestagen combined treatment.

Consumer health informatics: knowledge engineering and evaluation studies of medical HouseCall.

The changes in reimbursement structure in health care have given rise to a rapidly growing focus on the consumer and this recent increase has been fueled by the advent of the Web. Consumer health information (CHI) systems empower the consumer and aim to improve doctor-patient communication. We present HouseCall, a CHI system. First, this paper reviews how a consumer information system can be derived from an existing physician knowledge base (Iliad). Second, it presents evaluation studies that: 1) show how consumers are eager for non 'dumbed-down' content with easy access, 2) demonstrate the large spectrum of topics of interest and the 'natural' search strategies of health care consumers.

Conservation of apoptosis as an immune regulatory mechanism: effects of cortisol and cortisone on carp lymphocytes.

This is the first study to show that apoptosis as an immune regulatory mechanism is conserved in fish, demonstrating its importance in maintaining immunological homeostasis. The data further show that this mechanism is subject to control by glucocorticosteroids. Carp plasma cortisol concentrations increase from 20 to 434 ng/ml and cortisone from 5 to 50 ng/ml within 9 min of the onset of handling stress. At basal steroid concentrations in vitro, cortisol, but not its conversion product cortisone, inhibits proliferation of peripheral blood lymphocytes (PBL), as measured by [3H]thymidine incorporation. Induction of apoptosis in activated PBL is the apparent mechanism of cortisol action. In nonstimulated PBL cultures, apoptosis is induced by neglect (a lack of stimulating signals). Stimulation with LPS or PHA rescues lymphocytes from this type of apoptosis. Stimulated PBL populations, however, are sensitive to cortisol-induced apoptosis. Culture supernatants from activated PBL protect PBL from apoptosis by neglect, probably by supplying a growth signal. These supernatants, however, have no effect on cortisol-induced apoptosis.

Qualitative analysis of temporal information in Iliad: implications for linking Iliad to an electronic medical record as a knowledge server.

In linking Iliad to an electronic medical record (EMR) as a knowledge server, our objective is to convert the date and time stamped data from the EMR to the temporal representations existing in the Iliad knowledge base. First, an empirical analysis of Iliad's temporal information content is described: categorizing, estimating the amount (22%), and offering a temporal template to canonically represent it. Second, we analyze the effect of history and physical examination temporal information on the diagnostic performance of the system using data from 241 real cases. Third, we discuss knowledge engineering mapping techniques to convert time information found in EMRs. We conclude that the Iliad system includes a large amount of explicit and implicit time information and this information improves the system's diagnostic accuracy, both in terms of diagnosis ranking and confidence.

Iliad and Medical HouseCall: evaluating the impact of common sense knowledge on the diagnostic accuracy of a medical expert system.

Diagnostic expert systems are gaining acceptance among physicians. Recently, a comparative study of the performance of four major commercial diagnostic programs demonstrated that the information they produce contains a certain amount of irrelevancy that the trained physician ignores. Medical HouseCall is a consumer health information expert system based on a medical expert system for physicians, Iliad. To enhance the usefulness of Medical HouseCall to health care consumers, we are interested in significantly reducing the amount of irrelevancy contained in the diagnostic differential list. Testing with over 470 'textbook' cases revealed that a large part of the irrelevancy can be eliminated by adding universal and medical 'common sense' knowledge. Using four performance measures, we compared, on a subset of cases, the differential lists from two versions of the program: the refined knowledge base (1995) and an older version (1994) 'pre-common sense'. The results suggest that the performance of a diagnostic expert system can be significantly improved with the addition of common sense knowledge.

Gas chromatographic-mass spectrometric (GC-MS) analysis of gonadal steroids in plasma of the male African catfish, Clarias gariepinus: effects of castration or treatment with gonadotropin releasing hormone analogue.

To identify testicular steroids that may be involved in the feedback mechanisms of the hypothalamus-pituitary-gonad axis in African catfish, Clarias gariepinus, steroids, which are known to be produced by the testis in vitro, were identified and quantified in blood plasma before and after castration using gas chromatography followed by mass spectrometry. Before castration 20 testicular steroids were detected. Quantitatively dominant steroids were testosterone (16.9 +/- 4.3 ng/ml), androstenedione (12.0 +/- 3.9 ng/ml), and 11-ketotestosterone (6.7 +/- 1.8 ng/ml). After castration, only these steroids showed a strong decrease in plasma, indicating that they are of testicular origin. Assuming that steroids involved in the feedback to the pituitary are under gonadotropic control, fish were injected with two doses of a salmon gonadotropin releasing hormone analogue (sGnRHa). The lower sGnRHa dose (0.25 microgram/kg body weight) increased plasma GTH-II levels in the same range as those induced by castration, resulting in a significant increase in plasma levels of testosterone, androstenedione, and 11-ketotestosterone. After injection of a higher dose of sGnRHa (5.0 micrograms/kg body weight), there was a greater increase in plasma GTH-II level, as well as a significant increase in most of the other steroids studied. The decreased levels of testosterone, androstenedione, and 11-ketotestosterone after castration and the significant increase in these steroids following moderate GTH stimulation, suggest that one or more of these steroids plays a role in the feedback mechanism within the hypothalamus-pituitary-gonad axis.

Distribution and regulation of estrogen-2-hydroxylase in the quail brain.

The anatomical distribution and endocrine regulation of the estrogen-2-hydroxylase activity were investigated in the brain of adult male and female Japanese quail. Significant levels of enzymatic activity were detected in all brain regions that were studied, but the highest levels were observed in preoptic and hypothalamic brain nuclei that are known to contain high levels of aromatase activity. These data are consistent with previous results suggesting that the placental aromatase is also responsible for the estrogen-2-hydroxylase activity. However, there is a marked sex difference and a control by T of aromatase activity in the quail brain, and no such difference in 2-hydroxylase activity could generally be detected except in the VMN. Further studies will be needed to know whether the previously published conclusions concerning the human placenta also apply to the brain. The present data are consistent with the idea that estrogens formed locally in the brain by testosterone aromatization could affect reproduction by interfering with the catecholaminergic transmission after being metabolized into catechol-estrogens.

Steroid hormone secretion by testicular tissue from African catfish, Clarias gariepinus, in primary culture: identification and quantification by gas chromatography - mass spectrometry.

With the final aim of identifying the testicular steroids involved in the feedback mechanism of the hypothalamus-pituitary-gonad axis, steroid secretion by the testis of African catfish, Clarias gariepinus, was studied in vitro, by means of gas chromatography followed by mass spectrometry. Testicular fragments of sexually mature catfish raised in captivity were incubated in L-15 medium with and without catfish pituitary extract (cfPE). Without adding cfPE, 22 steroids could be identified, amongst which 11ß-hydroxyandrostenedione, 11ß-hydroxytestosterone, 11-ketotestosterone and 11-ketoandrostenedione were dominating. After incubation in the presence of cfPE, the concentrations of the four 11-oxygenated steroids were increased about 4-fold. The amounts of pregnane derivatives in the incubation medium showed the largest increases in the presence of cfPE. 5ß-Pregnane-triol levels, for example, were 60-fold higher than in the medium from control incubations. The secretion of 5α- and 5ß-androstanes was also stimulated by cfPE.The stimulation was not equal for all steroids, indicating that cfPE not only stimulates total steroidogenesis by increasing the availability of cholesterol, but also by influencing specific steroid converting enzyme activities.

On the origin of vertebrate-type steroids present in Locusta migratoria: do they originate from the food?

1. This study investigates the origin of vertebrate-type steroids which were reported to be present in Locusta migratoria: are the steroids synthesized by the locust or are they derived from the diet, i.e. grass and rolled oats? 2. It is unlikely that the steroids are synthesized by locust tissues. In vitro incubations of eleven different tissues with labeled pregnenolone or androstenedione did not result in androgen or estrogen synthesis respectively. 3. Steroid synthesis was also not detected when tissues were incubated in the presence of the early precursors cholesterol and isopentenyl pyrophosphate. 4. It is unlikely that the steroids are derived from the diet. Feeding experiments indicate that only low amounts of steroids are capable of crossing the gut-body barrier. 5. Injection of testosterone in the hemolymph also resulted in rapid excretion, instead of storage in tissues. 6. Moreover, radioimmunological measurements indicate that vertebrate-type steroids are absent in the food of locusts. 7. Specificity studies indicate that substances other than vertebrate-type steroids are detected by radioimmunoassay in locust tissue extracts. 8. Because vertebrate-type steroids are absent in locust tissues, it can be concluded that vertebrate-type steroids do not have a physiological function in Locusta.