ABP688, a novel selective and high affinity ligand for the labeling of mGlu5 receptors: identification, in vitro pharmacology, pharmacokinetic and biodistribution studies

[(11)C]ABP688 (2) has recently been demonstrated to be a useful PET tracer for in vivo imaging of the metabotropic glutamate receptors type 5 (mGluR5) in rodents. We describe here the identification and preclinical profiling of ABP688 and its tritiated version [(3)H]ABP688, and show that its high affinity (K(d)=2nM), selectivity, and pharmacokinetic properties fulfill all requirements for development as a PET tracer for clinical imaging of the mGlu5 receptor.     

Xenobiotic effects on ovarian preantral follicles

Women are born with a finite population of ovarian follicles, which are slowly depleted during their reproductive years until reproductive failure (menopause) occurs. The rate of loss of primordial follicles is determined by genetic and environmental influences, but certain toxic exposures can accelerate this process. Ionizing radiation reduces preantral follicle numbers in rodents and humans in a dose-dependent manner. Cigarette smoking is linked to menopause occurring 1-4 yr earlier than with nonsmokers, and components of smoke, polycyclic aromatic hydrocarbons, can cause follicle depletion in rodents or in ovaries in vitro. Chemotherapeutic agents, such as alkylating drugs and cisplatin, also cause loss of preantral ovarian follicles. Effects depend on dose, type, and reactivity of the drug, and the age of the individual. Evidence suggests DNA damage may underlie follicle loss induced by one common alkylating drug, cyclophosphamide. Occupational exposures have also been linked to ovarian damage. In an industrial setting, 2-bromopropane caused infertility in men and women, and it can induce ovarian follicle depletion in rats. Solvents, such as butadiene, 4-vinylcyclohexene, and their diepoxides, can also cause specific preantral follicle depletion. The mechanism(s) underlying effects of the latter compound may involve alterations in apoptosis, survival factors such as KIT/Kit Ligand, and/or the cellular signaling that maintains primordial follicle dormancy. Estrogenic endocrine disruptors may alter follicle formation/development and impair fertility or normal development of offspring. Thus, specific exposures are known or suspected of detrimentally impacting preantral ovarian follicles, leading to early ovarian failure.     

Roles and Programming of Arabidopsis ARGONAUTE Proteins during Turnip Mosaic Virus Infection

In eukaryotes, ARGONAUTE proteins (AGOs) associate with microRNAs (miRNAs), short interfering RNAs (siRNAs), and other classes of small RNAs to regulate target RNA or target loci. Viral infection in plants induces a potent and highly specific antiviral RNA silencing response characterized by the formation of virus-derived siRNAs. Arabidopsis thaliana has ten AGO genes of which AGO1, AGO2, and AGO7 have been shown to play roles in antiviral defense. A genetic analysis was used to identify and characterize the roles of AGO proteins in antiviral defense against Turnip mosaic virus (TuMV) in Arabidopsis. AGO1, AGO2 and AGO10 promoted anti-TuMV defense in a modular way in various organs, with AGO2 providing a prominent antiviral role in leaves. AGO5, AGO7 and AGO10 had minor effects in leaves. AGO1 and AGO10 had overlapping antiviral functions in inflorescence tissues after systemic movement of the virus, although the roles of AGO1 and AGO10 accounted for only a minor amount of the overall antiviral activity. By combining AGO protein immunoprecipitation with high-throughput sequencing of associated small RNAs, AGO2, AGO10, and to a lesser extent AGO1 were shown to associate with siRNAs derived from silencing suppressor (HC-Pro)-deficient TuMV-AS9, but not with siRNAs derived from wild-type TuMV. Co-immunoprecipitation and small RNA sequencing revealed that viral siRNAs broadly associated with wild-type HC-Pro during TuMV infection. These results support the hypothesis that suppression of antiviral silencing during TuMV infection, at least in part, occurs through sequestration of virus-derived siRNAs away from antiviral AGO proteins by HC-Pro. These findings indicate that distinct AGO proteins function as antiviral modules, and provide a molecular explanation for the silencing suppressor activity of HC-Pro.     

Design and synthesis of potent thiol-based inhibitors of endothelin converting enzyme-1

Through directed screening of compounds prepared as metalloprotease inhibitors a compound, CGS 30084, that had potent endothelin converting enzyme-1 (ECE-1) in vitro inhibitory activity (IC50 = 77 nM) was identified. Herein we report the synthesis and optimization of ECE-1 inhibitory activity of additional analogues from this lead. Compound 3c, the thioacetate methyl ester derivative of compound 4c, was found to be a long acting inhibitor of ECE-1 activity in rats after oral administration.     

Ergoline derivatives as highly potent and selective antagonists at the somatostatin sst 1 receptor

Non-peptidic compounds containing the octahydro-indolo[4,3-fg]quinoline (ergoline) structural element have been optimized into derivatives with high affinity (pK(d) r sst(1)>9) and selectivity (>1000-fold for h sst(1) over h sst(2)-h sst(5)) for the somatostatin sst(1) receptor. In functional assays, these ergolines act as antagonists at human recombinant sst(1) receptors. Pharmacokinetic studies in rodents reveal good oral bioavailability and brain penetration for some of these compounds.     

Inhibition of Candida albicans adhesion by recombinant human antibody single-chain variable fragment specific for Als3p

The Candida albicans adhesin, Als3p, was identified as a potential cognate antigen for previously described human antibody fragments [single-chain variable fragment (scFv)] based on similarity of the binding pattern of the scFv to the distribution of this protein on the hyphal surface. Although all scFv bound avidly to wild type, scFv3 showed no detectable binding via immunofluorescence assay to strain 1843, containing a homozygous deletion of ALS3. Binding to the ALS3 reintegrant strain, 2322, was preserved, and scFv3 also bound to Saccharomyces cerevisiae expressing ALS3. Other scFv retained binding to 1843, but with a markedly altered pattern. To determine if scFv3 could interfere with Als3p function, adhesion assays were conducted using human epithelial or endothelial cells as target. Treatment of wild-type C. albicans with scFv3 reduced adhesion of the fungus to both cell types to levels comparable to the als3Delta/als3Delta mutant. These experiments confirm that phage display is a viable method to isolate human scFv specific to an antigen implicated in C. albicans virulence, and that the scFv interfere with adhesion to human cells. The altered pattern of immunostaining with other scFv that retain binding to the als3Delta/als3Delta mutant suggest that Als3p may also have a role in structural organization of the C. albicans cell surface.     

Angststörungen in der Schwangerschaft und nach der Geburt:

Anxiety disorders are widespread. In contrast to affective disorders, they are characterized by a high persistence and a low remission rate. A considerable number of women suffer from anxiety disorders not only prior to conception but also throughout the transition into parenthood. The detection of anxiety disorders is complicated by the overlap of somatic and anxiety symptoms. Additionally, certain anxiety syndromes are specifically exacerbated during pregnancy. We present the diagnostic criteria of the most important anxiety disorders and highlight the symptoms that make an adequate diagnosis during pregnancy difficult. We outline the natural course and delineate options for referral and intervention.     

Effects of 4-Vinylcyclohexene Diepoxide on Peripubertal and Adult Sprague�CDawley Rats: Ovarian, Clinical, and Pathologic Outcomes

Young rats treated daily with intraperitoneal 4-vinylcyclohexene diepoxide (VCD) undergo selective destruction of primordial follicles, resulting in gradual ovarian failure resembling the menopausal transition in women. To determine whether VCD has similar effects on ovaries of older rats, adult and peripubertal Sprague–Dawley rats were injected intraperitoneally daily for 30 d with vehicle or VCD at 40 or 80 mg/kg. Body weight, food intake, complete blood counts, and markers of liver injury and renal function were measured during VCD treatment. Complete gross necropsy and microscopic observations were performed on day 31, and ovarian follicles were counted. At 80 mg/kg, VCD destroyed primordial and primary follicles to a similar extent in both adult and peripubertal animals, although adult rats likely started with fewer follicles and therefore approached follicle depletion. Treatment with VCD did not affect body weight, but food intake was reduced in both adult and peripubertal rats treated with 80 mg/kg VCD. Adult rats treated with 80 mg/kg VCD had neutrophilia and increased BUN and creatinine; in addition, 4 of these rats were euthanized on days 25 or 26 due to peritonitis. VCD treatment did not increase alanine aminotransferase levels, a marker of liver injury, although the 80-mg/kg dose increased liver weights. In conclusion, VCD effectively destroys small preantral follicles in adult Sprague–Dawley rats, making them a suitable model of the menopausal transition of women. However, because adult rats were more sensitive to the irritant properties of VCD, the use of a lower dose should be considered.Abbreviations: VCD, 4-vinylcyclohexene diepoxideStudies attempting to model the human menopause have relied heavily on using animals from which the ovaries have been removed surgically (ovariectomy). This approach has important limitations because women who enter natural menopause still have ovaries, which continue to produce hormones. Therefore, studies using ovariectomized animals cannot model the hormonal changes associated with the menopausal transition and postmenopausal period. However, rodent models of the menopausal transition and menopause that more closely mimic those of women have recently been developed.^32,33,36 Mice or rats treated with daily intraperitoneal injections of the chemical 4-vinylcyclohexene diepoxide (VCD) undergo selective destruction of primordial and primary follicles.²⁵ This treatment results in a gradual onset of ovarian failure because remaining larger follicles continue to develop and then ovulate or undergo atresia until they are depleted.³⁶ These studies also demonstrate that the length of time to ovarian failure is dependent on VCD dose and duration of treatment.^33,37 Moreover, in VCD-treated mice, the resulting follicle-depleted, stroma-intact ovary retains the ability to produce androgens.³⁶ Therefore, taken together, these characteristics indicate that VCD-treated animals could be used to model the menopausal transition of women and enable research on diseases affecting women postmenopausally.The ability of VCD to destroy preantral follicles in rats by repeated dosing has been well documented.^16,23,24,37 However, to our knowledge, all of the VCD studies using rats that have been published to date have used peripubertal or young (28 to 58 d) Fisher 344 rats. Although younger animals have been useful in separating the effect of age from the effect of hormonal changes associated with VCD-induced ovarian failure,^22,27,32,37 the use of older rodents may provide a more appropriate model for studying the combined effects of aging and hormonal aspects of menopause (for example, osteoporosis, cognitive decline, ovarian cancer).Both young and adult Sprague–Dawley rats have been used extensively to model menopausal effects on osteoporosis,^3,4,13,38,49 brain and cognitive functioning,^{2,14,15,29,34} lipids and cardiovascular health,^30,35,53 bladder health and incontinence,^6,21,31 and breast cancer.^8,18,43,44 These studies used ovariectomized Sprague–Dawley rats ranging in age from 42 to 210 d. The use of this chemically induced model of menopause would be enhanced by determining whether VCD affects Sprague–Dawley rats differently and whether VCD has deleterious effects on nonovarian tissues. Furthermore, although more than a dozen publications have reported that repeated VCD dosing does not adversely affect young rodents,^{19,32,33,36,56} similar data have not been reported for adult Sprague–Dawley rats. The purpose of this study was to determine whether VCD affects the ovaries of peripubertal (28 d) and adult Sprague–Dawley rats differently.     

Characterisation of the interaction between circulating and in vitro cultivated endothelial progenitor cells and the endothelial barrier

In vitro cultured endothelial progenitor cells (cEPC) are used for intracoronary cell therapy in cardiac regeneration. The aim of this study was to investigate whether cEPC and circulating mononuclear cells (MNC), which include a small number of in vivo circulating EPC, are able to transmigrate through the endothelial barrier into the cardiac tissue. MNC and EPC were isolated from the peripheral blood from healthy male volunteers (n = 13, 25+/-6 years) and stained with a fluorescent marker. The cells were perfused in vitro through organs with endothelial layers of different phenotypes (rat aorta, human umbilical vein, isolated mouse heart). The endothelium and the basal lamina were then stained by immunofluorescence and the cryo-sections analysed using a confocal laser scanning microscope. After perfusion through the rat aorta, an adhesion/integration of MNC was observed at the endothelial layer and the basal lamina beneath endothelial cells. However, no migration of MNC over the endothelial barrier was found. This remained true even when the cell numbers were increased (from 0.5 to 10 million cells/h), when the time of perfusion was prolonged (1.5-4 h) and when the aorta was cultivated for 24 h. In the Langendorff-perfused mouse heart with intact endothelium, no migration of MNC (1 x 10(7)) or cEPC (1 x 10(6)) was observed after 0.5 and 2 h. In conclusion, MNC and cEPC do not possess any capacity to transmigrate the endothelial barrier. In the context of stem cell therapy, these cells may therefore serve as endothelial regenerators but not as cardiomyocyte substitutes.     

Angiotensin II,vasopressin and GTP[γ-S] inhibit inward-rectifying K+ channels in porcine cerebral capillary endothelial cells

Summary Cerebral capillaries from porcine brain were isolated. and endothelial cells were grown in primary culture. The whole-cell tight seal patch-clamp method was applied to freshly isolated single endothelial cells, and cells which were held in culture up to one week. With high K⁺ solution in the patch pipette and in the bath we observed inward-rectifying K⁺ currents, showing a time-dependent decay in part of the experiments. Ba²⁺ (1–10mm) in the bath blocked this current, whereas outside tetraethylammonium (10mm) decreased the peak current but increased the steady-state current. Addition of 1 m of angiotensin II or of arginine-vasopressin to the extracellular side caused a time-dependent inhibition of the inward-rectifying K⁺ current in part of the experiments. Addition of 100 m GTP[-S] to the patch pipette blocked the K⁺ inward rectifier. In cell-attached membrane patches two types of single inward-rectifying K⁺ channels were observed, with single channel conductances of 7 and 35 pS. Cell-attached patches were also obtained at the antiluminal membrane of intact isolated cerebral capillaries. Only one type of K⁺ channel withg=30 pS was recorded. In conclusion, inwardly rectifying K⁺ channels, which can be inhibited by extracellular angiotensin II and arginine-vasopressin, are present in cerebral capillary endothelial cells. The inhibition of this K⁺ conductance by GTP[-S] indicates that G-proteins are involved in channel regulation. It is suggested that angiotensin II and vasopressin regulate K⁺ transport across the blood-brain barrier, mediating their effects via G-proteins.