Experiences with dose finding in patients in early drug development: the use of biomarkers in early decision making

With the increasing cost and complexity of drug development, biomarkers will play an increasing role in the early phases. Biomarkers can be classified into target, mechanistic, or outcome with varying degrees of linkage to disease or treatment effect. They can be used to determine proof of concept by characterising the efficacy or safety profiles, or determining differentiation from any competitor drugs. PK/PD modelling of biomarker data for novel and marketed compounds can be used to predict outpatient dose response. Subsequent simulations may replace or reduce the size and cost of larger phase 2b outpatient studies. Two examples of biomarkers and PK/PD modelling used to characterise dose response are presented. Penile plethysmography (RigiScan Plus) in male erectile dysfunction and phenylephrine challenge urethral pressure in benign prostatic hyperplasia are used to reduce time and cost to reach major exploratory development decision points in these indications.

[Adhesional inhibiton of polyclonal anti-porin I antibody]

OBJECTIVE

To investigate the blockness effects of purified polyclonal anti-porin I antibody on N. gonorrhoeae adherence to genitourinary tract epithelia of BALB/c mouse.

METHODS

Polyclonal anti GST-PI antibody was generated by immunizing rabbit with GST-PI fusion protein which was constructed and expressed by ourselves. The purified immunoglobulin G was obtained by ammonium sulphate deposition and DEAE cellulose chromatography. Mice model of gonorrhea was established. In order to evaluate the effects of PI-IgG on gonococcus adhesion to vagina mucus, the macroscopic and pathological assessing as well as gonococcus culture was employed after gonococcus challenge on PI-IgG immunized mice.

RESULT

No pus and pathological inflammation were observed on mice vagina mucus treated with 1 mg/ml PI-IgG 3 hours before gonococcus challenge. Gonococcus could not be detected in the smears and washing solutions from vagina. Pathological inflammation was found in mice treated with anti PI-IgG, in which the concentrations were lower than 1 mg/ml or the treated time was longer than 3 hours prior to gonococcus challenge.

CONCLUSION

The purified anti PI-IgG can effectively inhibit the adherence and infection of gonococci to genitourinary tract epithelia of BALB/c mice. In addition, the blocking duration of anti PI-IgG is associated with antibody concentration.

The controversies regarding the role of estrogens in urogynecology

Estrogens are crucial for the proper functioning of genitourinary tract. Hypoestrogenism related to menopause could be linked to numerous disturbances of lower urinary tract. However, the results of most well designed clinical studies do not support use of estrogen or hormone replacement therapy for the treatment of genitourinary symptoms. According to evidence base medicine stress urinary incontinence, overactive bladder syndrome or pelvic organ prolapse are best treated by the surgery or non-hormonal drug therapy.

Oxymorphone Hydrochloride, a Potent Opioid Analgesic, Is Not Carcinogenic in Rats or Mice

Despite their long history of chronic use, little information is available regarding the carcinogenicity of opioid analgesics. Oxymorphone is a potent morphinan-type mu-opioid analgesic used for treatment of moderate-to-severe pain. Oxymorphone was tested for carcinogenicity in Crl:CD IGS BR rats and CD-1 mice. Oxymorphone hydrochloride was administered orally once daily for 2 years to rats at doses of 2.5, 5 and 10 mg/kg/day (males) and 5, 10 and 25 mg/kg/day (females), and mice at 10, 25, 75 and 150 mg/kg/day (65 animals per sex per group; 100 animals per sex in controls). In rats, survival was generally higher than controls in oxymorphone-treated groups, attributable to lower body weight gain. In mice, survival was generally higher than controls in females at all doses and males given < or = 25 mg/kg/day but lower in males given > or = 75 mg/kg/day due to a high incidence of obstructive uropathy. Opioid-related clinical signs and reduced body weight gain occurred in both species throughout the study. Nonneoplastic findings associated with oxymorphone pharmacology included ocular and pulmonary changes in rats considered secondary to inhibition of blinking and mydriasis, and antitussive activity, respectively, and urinary tract and renal findings in mice considered secondary to urinary retention. There was no target organ toxicity, and no increase in any neoplastic lesions attributed to oxymorphone. Plasma oxymorphone levels achieved in these studies exceeded those in patients taking high therapeutic doses of oxymorphone (Area under the curve [AUC(0-24 h)] values up to 5.6-fold and 64-fold in rats and mice, respectively). Oxymorphone is not considered to be carcinogenic in rats or mice under the conditions of these studies.

Isolation and characterization of an immortalized mouse urogenital sinus mesenchyme cell line

BACKGROUND

Stromal-epithelial signaling plays an important role in prostate development and cancer progression. Study of these interactions will be facilitated by the use of suitable prostate cell lines in appropriate model systems.

METHODS

We have isolated an immortalized prostate mesenchymal cell line from the mouse E16 urogenital sinus (UGS). We characterized its expression of stromal differentiation markers, response to androgen stimulation, ability to induce and participate in prostate morphogenesis, response to Shh stimulation, and interaction with prostate epithelial cells.

RESULTS

UGSM-2 cells express vimentin and smooth muscle actin, but not the mature smooth muscle markers myosin and desmin. This expression profile is consistent with a myofibroblast phenotype. Unlike other fibroblasts such as 3T3, UGSM-2 cells express androgen receptor mRNA and androgen stimulation increases proliferation. UGSM-2 cells are viable when grafted with embryonic UGS under the renal capsule and participate in glandular morphogenesis, but are not capable of inducing prostate morphogenesis of isolated UGS epithelium. Co-culture of UGSM-2 cells with human BPH-1 cells or co-grafting in vivo results in organized clusters of BPH-1 cells surrounded by a mantle of UGSM-2 cells. UGSM-2 cells are responsive to Sonic hedgehog (Shh), an important signaling factor in prostate development, and mimic the transcriptional response of the intact UGS mesenchyme. In co-cultures with BPH-1, UGSM-2 cells exhibit a robust transcriptional response to Shh secreted by BPH-1.

CONCLUSIONS

UGSM-2 is a urogenital sinus mesenchyme cell line that can be used to study stromal-epithelial interactions that are important in prostate biology.

[Adverse health effects of cadmium and related factors]

Cd is a very toxic chemical to animal and human beings. Cd contamination has been ubiquitous because of industry and the human activities. Cd not only affects adversely the growth, yield and quality of crops but also effects on the health of animal and human being. The damage of Cd on bone, kidney, liver, immune and procreation systems as well possible factors that influence Cd absorption, accumulation and damage in the body are summarized in this paper.

Histopathology and histomorphometry of the urogenital tract in 15-month old male and female rats treated neonatally with SERMs and estrogens

In this study, two selective estrogen receptor modulators (SERMs), tamoxifen (TAM) and toremifene (TOR) or two estrogens, ethinylestradiol (EE) and diethylstilbestrol (DES) were administered to newborn male and female Sprague-Dawley rats (days 1-5) to investigate the occurrence of developmental abnormalities in the adulthood. The compounds were dosed (s.c.) at an equimolar dose of 24.9 micromol/kg. During the follow-up period, mortality occurred mainly in DES-treated male rats (3/4), associated with obstructive urinary calculi and suppurative renal inflammation in 2/3 rats. Similar lesions were not evident in other groups. At the age of 15 months, the animals were necropsied and organs were collected for histopathology and histomorphometry. Treatment-related abnormalities were restricted to the reproductive organs. Chronic prostatitis and epithelial abnormalities in the vas deferens were observed in all treatment groups. The columnar epithelium of vas deferens showed hyperplasia and development of subepithelial glandular structures resembling epididymal cysts reported in humans exposed in utero to DES. Testicular atrophy was observed especially in estrogen-treated rats. Mainly in SERM-treated female rats, the uterus showed luminal dilation or obstruction, loss of endometrial glands and myometrium disorganization including foci of muscular disruption. TOR-treated female rats showed polyp-like nodules (incidence 4/15) and a high incidence (9/15) of a simple cuboidal epithelium in cervical regions normally occupied by multilayered epithelia. In conclusion, the vas deferens is a main target organ following neonatal administration of SERMs and estrogens. In addition, female rats were significantly more susceptible to SERM treatment than to treatment with estrogens.

Urogenital papilla feminization in male Pomatoschistus minutus from two estuaries in northwestern Iberian Peninsula

Recently, male urogenital papilla feminization (UGPF) in the sand goby Pomatoschistus minutus was reported in several UK estuaries with high levels of estrogenic compounds. The fact that this species is also common in southern European estuaries, together with its life-cycle characteristics, prompted us to investigate P. minutus UGPF in the northwestern of Iberian Peninsula. Specimens of P. minutus were periodically sampled during 2004 at several locations in two estuaries (Minho and Lima). Evidence for UGPF was recorded in both estuaries, the highest incidence being observed in the Lima estuary (50%). Estrogen levels (17beta-estradiol and estrone) above 100 pg/l were observed in both estuaries, the higher concentrations being found in the Lima estuary. Overall, the results suggest a relationship between the feminization of male P. minutus urogenital papilla and the presence of estrogenic compounds. In the future, more in-depth studies are required in order to use P. minutus as a sentinel species for estrogenic compound monitoring in estuaries.

Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs

OBJECTIVE

To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs.

ANIMALS

3 sexually intact and 3 spayed female Beagles without urinary incontinence.

PROCEDURE

Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured.

RESULTS

Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog.

CONCLUSIONS AND CLINICAL RELEVANCE

Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.

Limited Penetration of Lopinavir and Ritonavir in the Genital Tract of Men Infected with HIV-1 in Brazil

The concentrations of lopinavir and ritonavir in seminal and blood plasma and the seminal human immunodeficiency virus (HIV) viral load were quantified by HPLC and the Nuclisens assay, respectively, in a cross-sectional study of 16 HIV-1-infected Brazilian men under stable treatment with a lopinavir/ritonavir containing antiretroviral regimen. Semen and blood samples were collected on 2 occasions: at 6 to 60 minutes before ("trough"), and 5 to 6 hours after ("peak") ingestion of regular doses of lopinavir/ritonavir. Median seminal lopinavir levels were 120.6 ng/mL (range, <20-1481.8 ng/mL) and 233.1 ng/mL (range, 48.4-1133.4 ng/mL) at trough and peak points, respectively. The corresponding values for ritonavir were 9.2 ng/mL (range, <5-47 ng/mL) and 17.1 ng/mL (range, 6.6-66.7 ng/mL). The median concentrations of lopinavir and ritonavir in semen were, respectively, 1.9% to 3% and 3.7% to 4.4% of those measured in blood plasma samples collected within 30 minutes. HIV-1 viral load was detectable in the semen of 2 and in the blood of 6 of 16 patients. These results may have implications for drug-resistant HIV-1 evolution and transmission.

Effect of aqueous leaf extract of Azadirachta indica on the reproductive organs in male mice

Effect of oral administration (50, 100, and 200 mg/kg body weight/day, for 28 days) of aqucous leaf extract of neem (Azadirachta indica) on the male reproductive organs of the Parkes (P) strain mice was investigated. The treatment had no effect on body weight and the reproductive organs weight. In treated mice, testes showed both normal and affected seminiferous tubules in the same sections; the affected seminiferous tubules showed intraepithelial vacuolation, loosening of germinal epithelium, marginal condensation of chromatin in round spermatids, occurrence of giant cells, mixing of germ cell types in stages of spermatogenesis and degenerated appearance of germ cells. In severe cases, the tubules were lined with Sertoli cells only, Sertoli cells and rare germ cells, or with Sertoli cells and several germ cells but without cellular association patterns. Also, the frequency of affected seminiferous tubules in testes of the extract-treated mice was significantly higher than the controls, though this remained unaffected in mice treated at 50 mg/kg body weight of the extract. Doses at 50 or 100 mg/kg body weight of neem leaf extract did not cause appreciable alterations in histological appearance of the epididymis, while a dose of 200 mg/kg body weight caused marked alterations both in histological appearance and the level of sialic acid in the duct. The treatment also had adverse effects on motility, morphology, and number of spermatozoa in the cauda epididymidis, level of fructose in the seminal vesicle, and on litter size. After 42 days of withdrawal of the treatment, the alterations induced in the reproductive organs recovered to control levels. Our results suggested that treatment with neem leaf extract caused reversible alterations in the male reproductive organs of P mice.

Effect of insulin treatment on tissue size of the genitourinary tract in BB rats with spontaneously developed and streptozotocin-induced diabetes

To examine the differences between spontaneous and streptozotocin (STZ)-induced diabetes, four parallel studies were performed; three studies of diabetes-prone BB (BBDP/Wor) rats maintained for 8, 16, and 32 weeks and one study of STZ-injected diabetes-resistant BB (BBDR/Wor) rats maintained for 32 weeks. Each diabetic study has three groups of rats: a control group; a euglycemic group, which received sufficient amounts of insulin; and a hyperglycemic group, which received a suboptimal dose of insulin. The extent of tissue weight changes was generally shown to be less dramatic in the euglycemic diabetic than in the hyperglycemic diabetic rats. STZ-induced diabetes increased the bladder weight more dramatically (up to 3-fold) than did spontaneous diabetes (up to 2-fold). Furthermore, a significant decrease in the size of the adrenal gland (20%) and testis (10%) is observed only with spontaneous diabetes, whereas a significant decrease in the size of the ventral prostate (30%) is observed only with STZ-induced diabetes, although the serum testosterone levels are similar in both groups. Our data demonstrate that there are differences in the effect of insulin treatment on the tissue size of the genitourinary tract between spontaneously developed and streptozotocin-induced diabetes in BB rats.

Impact of hormone therapy on acute radiotherapy toxicity in the treatment of prostate cancer

PURPOSE

To analyze the impact of neoadjuvant hormone therapy (HT) on acute gastrointestinal (GI) and genitourinary (GU) toxicity from radiotherapy (RT).

SCOPE

The toxicity rates of 480 consecutive prostate cancer patients were reviewed and compared using the chi2 test. Ordered logit regression analyses were performed including the major demographic, disease, and treatment factors. Although no reduction in acute GI toxicity from HT use was observed (P=0.067), a lower rate of acute GU toxicity was observed (P=0.002). No factor reached statistical significance on regression analysis.

CONCLUSIONS

Observed toxicity rates were similar or lower in patients receiving HT. Thus, increased RT toxicity should not be a concern when deciding to add neoadjuvant HT to RT for prostate cancer.

Effects of capsaicin on visceral smooth muscle: a valuable tool for sensory neurotransmitter identification

Studying the visceral effects of the sensory stimulant capsaicin is a useful and relatively simple tool of neurotransmitter identification and has been used for this purpose for approximately 25 years in the authors' and other laboratories. We believe that conclusions drawn from experiments on visceral preparations may have an impact on studies dealing with the central endings of primary afferent neurons, i.e. research on nociception at the spinal level. The present review concentrates on the effects of capsaicin--through the transient receptor potential vanilloid receptor type 1 (TRPV1) receptor--on innervated gastrointestinal, respiratory and genitourinary smooth muscle preparations. Tachykinins and calcitonin gene-related peptide (CGRP) are the most widely accepted transmitters to mediate "local efferent" effects of capsaicin-sensitive nerves in tissues taken from animals. Studies more and more frequently indicate a supra-additive interaction of various types of tachykinin receptors (tachykinin NK(1), NK(2), NK(3) receptors) in the excitatory effects of capsaicin. There is also evidence for a mediating role of ATP, acting on P(2) purinoceptors. Non-specific inhibitory actions of capsaicin-like drugs have to be taken into consideration while designing experiments with these drugs. Results obtained on human tissues may be sharply different from those of animal preparations. Capsaicin potently inhibits tone and movements of human intestinal preparations, an effect mediated by nitric oxide (NO) and/or vasoactive intestinal polypeptide.

Long-term androgen deprivation increases Grade 2 and higher late morbidity in prostate cancer patients treated with three-dimensional conformal radiation therapy

PURPOSE

To determine whether the use of androgen deprivation (AD) increases late morbidity when combined with high-dose three-dimensional conformal radiation therapy (3D-CRT).

METHODS AND MATERIALS

Between May 1989 and November 1998, 1,204 patients were treated for prostate cancer with 3D-CRT to a median dose of 74 Gy. Patients were evaluated every 3-6 months. No AD was given to 945 patients, whereas 140 and 119 patients, respectively, received short-term AD (STAD; < or =6 months) and long-term AD (LTAD; > 6 months). Radiation morbidity was graded according to the Fox Chase modification of the Late Effects Normal Tissue Task Force late morbidity scale. Covariates in the multivariate analysis (MVA) included age, history of diabetes mellitus, prostate-specific antigen (PSA) level, Gleason score, T category, RT field size, total RT dose, use of rectal shielding, and AD status (no AD vs. STAD vs. LTAD).

RESULTS

The only independent predictor for Grade 2 or higher genitourinary (GU) morbidity in the MVA was the use of AD (p = 0.0065). The 5-year risk of Grade 2 or higher GU morbidity was 8% for no AD, 8% for STAD, and 14% for LTAD (p = 0.02). Independent predictors of Grade 2 or higher gastrointestinal (GI) morbidity in the MVA were the use of AD (p = 0.0079), higher total radiation dose (p < 0.0001), the lack of a rectal shield (p = 0.0003), and older age (p = 0.0009). The 5-year actuarial risk of Grade 2 or higher GI morbidity was 17% for no AD vs. 18% for STAD and 26% for LTAD (p = 0.017).

CONCLUSIONS

The use of LTAD seems to significantly increase the risk of both GU and GI morbidity for patients treated with 3D-CRT.

Tachykinins and tachykinin receptors: effects in the genitourinary tract

Tachykinins (TKs) are a family of peptides involved in the central and peripheral regulation of urogenital functions through the stimulation of TK NK1, NK2 and NK3 receptors. At the urinary system level, TKs locally stimulate smooth muscle tone, ureteric peristalsis and bladder contractions, initiate neurogenic inflammation and trigger local and spinal reflexes aimed to maintain organ functions in emergency conditions. At the genital level, TKs are involved in smooth muscle contraction, in inflammation and in the modulation of steroid secretion by the testes and ovaries. TKs produce vasodilatation of maternal and fetal placental vascular beds and appear to be involved in reproductive function, stress-induced abortion, and pre-eclampsia. The current data suggest that the genitourinary tract is a primary site of action of the tachykininergic system.

Permanent induction of morphological abnormalities in the penis and penile skeletal muscles in adult rats treated neonatally with diethylstilbestrol or estradiol valerate: a dose-response study

This study evaluated the effects of neonatal exposure to different doses of diethylstilbestrol (DES) or estradiol valerate (EV) on penile morphology, penile skeletal muscles, and fertility. Male pups received DES or EV at a dose of 10 microg, 1 microg, 100 ng, 10 ng, or 1 ng per rat on alternate days from postnatal days 2-12. Fertility was tested at 120 days, and tissues were examined at 150 days. Generally, DES and EV induced similar effects within the 10- and 1-microg groups. Fertility was reduced to 0; the weight, length, and diameter of the penis and the weight of penile skeletal muscles, especially bulbocavernosus muscle, were decreased (P <.05) in a dose-dependent manner; the preputial sheath was partially released or its release was delayed; testicular descent was delayed; and the cavernous spaces and smooth muscle cells in the corpora cavernosa penis were replaced by fat cells. Conversely, all of the above parameters were similar in controls and the lower dose groups, except in the 100-ng DES group, in which 4 of 7 males did not sire pups (compared with 1 of 7 in controls and 2 of 6 in the 100-ng EV group). The loss of fertility in these 4 males of the DES group and 1 male of the EV group was associated with partial release of the preputial sheath and abnormal penile morphology. Plasma testosterone was reduced (P <.05) in the 100-ng and higher dose groups for DES and EV. Hence, neonatal exposure to DES or EV at a cumulative dose of 600 ng per rat or more lowers fertility, which is associated with permanent alterations in penile morphology and penile skeletal muscles and decreased testosterone.

REVIEW: Review of Phosphodiesterases in the Urogenital System: New Directions for Therapeutic Intervention

INTRODUCTION

With the success of Phosphodiesterase (PDE) type 5 inhibitors (i.e., sildenafil, tadalafil, vardenafil) in the treatment of erectile dysfunction (ED), PDEs are considered attractive targets for drug intervention in the urogenital tract.

AIM

To review the role of PDEs, which exist as a superfamily of enzymes comprising 11 distinct families, in the urogenital system, focusing on anatomical locations, functions and dysfunctions, potential disorders that could be treated, and any promising new selective PDE inhibitors under development.

METHODS

Included are (i) abstracts from 2001, 2002, and 2003; (ii) a MEDLINE search from 1996 through December 2003; and (iii) a pipeline search for therapeutics in development. Data from animal experiments are presented when there is a paucity of human data, but with the caveat that the distribution of PDE isozymes in a specific tissue can vary between species.

RESULTS

PDE mRNA and protein have been localized throughout the normal human urogenital tract. Double-blind, placebo-controlled studies suggest possible new clinical roles for sildenafil, including prophylaxis to preserve penile smooth muscle and erectile function after radical prostatectomy, and treatment of ejaculatory delay secondary to serotonergic reuptake inhibitor antidepressant therapy. Open-label studies suggest a potential clinical role for: vinpocetine (a PDE1 inhibitor) in the treatment of incontinence and low-compliance bladder; and sildenafil in the treatment of premature ejaculation, prostate-related lower urinary tract symptoms, and in women who have had unsuccessful in vitro fertilization. Several new orally administered PDE5 inhibitors are in early clinical development for the treatment of ED. Potential indications for PDE inhibitors that are suggested by preclinical data include Peyronie's disease, ureteral colic, male and female birth control, and prevention of preterm labor.

CONCLUSIONS

Drug selectivity and differential PDE tissue distribution allow for potential targeted intervention for numerous disorders related to the urogenital tract.

Role of thyroid hormones in human and laboratory animal reproductive health

The highly conserved nature of the thyroid gland and the thyroid system among mammalian species suggests it is critical to species survival. Studies show the thyroid system plays a critical role in the development of several organ systems, including the reproductive tract. Despite its highly conserved nature, the thyroid system can have widely different effects on reproduction and reproductive tract development in different species. The present review focuses on assessing the role of thyroid hormones in human reproduction and reproductive tract development and comparing it to the role of thyroid hormones in laboratory animal reproduction and reproductive tract development. The review also assesses the effects of thyroid dysfunction on reproductive tract development and function in humans and laboratory animals. Consideration of such information is important in designing, conducting, and interpreting studies to assess the potential effects of thyroid toxicants on reproduction and development.

2,3,7,8-tetrachlorodibenzo-p-dioxin inhibits prostatic epithelial bud formation by acting directly on the urogenital sinus

PURPOSE

In utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure causes lobe specific inhibition of prostate development in C57BL/6 mice due primarily to region specific inhibition of prostatic epithelial bud formation by the urogenital sinus (UGS). This inhibition requires that the receptor for TCDD, the aryl hydrocarbon receptor (AhR), must be present. We tested the hypothesis that TCDD inhibits prostatic epithelial bud formation by acting directly on the UGS.

MATERIALS AND METHODS

UGSs were removed from WT and AhR null mutant (AhRKO) male C57BL/6 mice on gestation day 14 and incubated in vitro with vehicle, 10-8 M testosterone or 10-8 M testosterone plus 10-9 M TCDD for 5 days. Budding was evaluated by a newly developed technique, namely scanning electron microscopy of UGS epithelium after removal of UGS mesenchyme.

RESULTS

Few buds were present in UGSs of either genotype in the absence of testosterone, while many were observed when testosterone was present. TCDD prevented prostatic epithelial buds from forming in UGSs from WT mice but it had no effect on UGSs from AhRKO mice.

CONCLUSIONS

TCDD can act directly on the UGS to cause AhR dependent inhibition of prostatic epithelial bud formation. Because this inhibition occurred at a TCDD concentration similar to the estimated concentration at which TCDD inhibits bud formation in vivo, it appears that TCDD inhibits prostatic budding primarily via direct effects on the UGS rather than indirectly through effects on other organs.

Efficacy of low-dose intravaginal estriol on urogenital aging in postmenopausal women

OBJECTIVE

To assess the efficacy and safety of intravaginal estriol administration on urinary incontinence, urogenital atrophy, and recurrent urinary tract infections in postmenopausal women.

DESIGN

Eighty-eight postmenopausal women with urogenital aging symptoms were enrolled in this prospective, randomized, placebo-controlled study. Participants were randomly divided into two groups, with each group consisting of 44 women. Women in the treatment group received intravaginal estriol ovules: 1 ovule (1 mg) once daily for 2 weeks and then 2 ovules once weekly for a total of 6 months as maintenance therapy. Women in the control group received inert placebo vaginal suppositories in a similar regimen. We evaluated urogenital symptomatology, urine cultures, colposcopic findings, urethral cytologic findings, urethral pressure profiles, and urethrocystometry before as well as after 6 months of treatment.

RESULTS

After therapy, the symptoms and signs of urogenital atrophy significantly improved in the treatment group in comparison with the control group. Thirty (68%) of the treated participants, and only seven (16%) of the control participants registered a subjective improvement of their incontinence. In the treated participants, we observed significant improvements of colposcopic findings, and there were statistically significant increases in mean maximum urethral pressure, in mean urethral closure pressure as well as in the abdominal pressure transmission ratio to the proximal urethra. Urethrocystometry showed positive but not statistically significant modifications.

CONCLUSIONS

Our results show that intravaginal administration of estriol may represent a satisfactory therapeutic choice for those postmenopausal women with urogenital tract disturbances who have contraindications or refuse to undergo standard hormone therapy.

The endocrine and reproductive system: adverse effects of hormonally active substances?

Chemicals that have the intrinsic property to modulate or even disrupt the endocrine system are present in the human environment. Because it is the potency of such chemicals that determines the toxicologic relevance, assessment of the risk to human health must consider both the endocrine disrupting potential and the potency. Usually in vitro assays are applied to detect the potential of a hormone-like effect, and such data are considered useful to set priorities for additional testing and for mechanistic studies. However, such data allow only determination of relative potency of a chemical as compared with other xenobiotics, natural compounds, or endogenous hormones. Relevant information on the endocrine-disrupting potency can be taken only from in vivo assays, eg, the Hershberger (male reproductive organs) and uterotrophic (female reproductive organs) assays, the updated versions of the 28- and 90-day toxicity studies in rodents, and the 2-generation studies in rodents. With the use of this information and the concentration of these chemicals in humans, the potency of the effect as compared with endogenous hormone activity can be estimated. So far, the relative potencies of chemicals tested in in vitro systems as compared with estradiol are several orders of magnitude smaller, whereas potency of the phytoestrogen, eg, isoflavones such as genistein or daidzein, can even exceed that of estradiol, especially in infants who are fed soy-based formula as a sole source of nutrition. Although there are still open questions regarding in utero or early postnatal exposure, the low potencies and concentrations of manmade chemicals as compared with the endogenous hormones in humans make it unlikely that adverse effects occur at common exposure.