Citalopram and sertraline exposure compromises embryonic bone development.

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed treatments for depression and, as a class of drugs, are among the most used medications in the world. Concern regarding possible effects of SSRI treatment on fetal development has arisen recently as studies have suggested a link between maternal SSRI use and an increase in birth defects such as persistent pulmonary hypertension, seizures and craniosynostosis. Furthermore, SSRI exposure in adults is associated with decreased bone mineral density and increased fracture risk, and serotonin receptors are expressed in human osteoblasts and osteoclasts. To determine possible effects of SSRI exposure on developing bone, we treated both zebrafish, during embryonic development, and human mesenchymal stem cells (MSCs), during differentiation into osteoblasts, with the two most prescribed SSRIs, citalopram and sertraline. SSRI treatment in zebrafish decreased bone mineralization, visualized by alizarin red staining and decreased the expression of mature osteoblast-specific markers during embryogenesis. Furthermore, we showed that this inhibition was not associated with increased apoptosis. In differentiating human MSCs, we observed a decrease in osteoblast activity that was associated with a decrease in expression of the osteoblast-specific genes Runx2, Sparc and Spp1, measured with quantitative real-time PCR (qRT-PCR). Similar to the developing zebrafish, no increase in expression of the apoptotic marker Caspase 3 was observed. Therefore, we propose that SSRIs inhibit bone development by affecting osteoblast maturation during embryonic development and MSC differentiation. These results highlight the need to further investigate the risks of SSRI use during pregnancy in exposing unborn babies to potential skeletal abnormalities.

Effects of beacon administration on energy expenditure and substrate utilisation in Psammomys obesus (Israeli sand rats).

OBJECTIVE: To investigate whether beacon administration affects substrate utilisation, physical activity levels or energy expenditure in Psammomys obesus. DESIGN: Pairs of age- and sex-matched Psammomys obesus were randomly assigned to either beacon-treated (15 microg/day for 7 days (i.c.v.)) or control (i.c.v. saline) groups. MEASUREMENTS: Indirect calorimetry on day 0 and day 7 to measure oxygen consumption and carbon dioxide production, which were used to calculate fat oxidation, carbohydrate oxidation and total energy expenditure. Physical activity in the calorimeter was measured using an infrared beam system. Food intake and body weight were measured daily. RESULTS: The administration of beacon significantly increased body weight compared to saline-treated control animals. This body weight gain was primarily due to increased body fat content. Average daily food intake tended to be higher in beacon-treated Psammomys obesus, but no effect of beacon administration on substrate oxidation, activity or energy expenditure was detected. CONCLUSION: The effects of beacon on body weight are due to increased food intake, with no detectable effect on nutrient partitioning, physical activity or energy expenditure.

ORP-3, a human oxysterol-binding protein gene differentially expressed in hematopoietic cells.

Using differential display polymerase chain reaction, a gene was identified in CD34(+)-enriched populations that had with low or absent expression in CD34(-) populations. The full coding sequence of this transcript was obtained, and the predicted protein has a high degree of homology to oxysterol-binding protein. This gene has been designated OSBP-related protein 3 (ORP-3). Expression of ORP-3 was found to be 3- to 4-fold higher in CD34(+) cells than in CD34(-) cells. Additionally, expression of this gene was 2-fold higher in the more primitive subfraction of hematopoietic cells defined by the CD34(+)38(-) phenotype and was down-regulated with the proliferation and differentiation of CD34(+) cells. The ORP-3 predicted protein contains an oxysterol-binding domain. Well-characterized proteins expressing this domain bind oxysterols in a dose-dependent fashion. Biologic activities of oxysterols include inhibition of cholesterol biosynthesis and cell proliferation in a variety of cell types, among them hematopoietic cells. Characterization and differential expression of ORP-3 implicates a possible role in the mediation of oxysterol effects on hematopoiesis.

Beacon: a novel gene involved in the regulation of energy balance.

The hypothalamus plays a major role in the control of energy balance via the coordination of several neuropeptides and their receptors. We used a unique polygenic animal model of obesity, Psammomys obesus, and performed differential display polymerase chain reaction on hypothalamic mRNA samples to identify novel genes involved in obesity. In this study, we describe a novel gene that encodes a small protein we have termed "beacon." Beacon mRNA gene expression in the hypothalamus was positively correlated with percentage of body fat. Intracerebroventricular infusion of beacon resulted in a dose-dependent increase in food intake and body weight and an increase in hypothalamic expression of neuropeptide Y (NPY). Simultaneous infusion of beacon and NPY significantly potentiated the orexigenic response and resulted in rapid body weight gain. These data suggest a role for beacon in the regulation of energy balance and body weight homeostasis that may be mediated, at least in part, through the NPY pathway.

Mutations in the hepatitis B virus precore/core gene and core promoter in patients with severe recurrent disease following liver transplantation.

Recurrent hepatitis B virus (HBV) infection is a major problem in patients undergoing liver transplantation. Previously, we reported that infection with HBV strains containing a mutation in the precore region (G-to-A at nucleotide 1896) was associated with severe recurrent disease posttransplantation. In this study we investigated other mutations in the precore/core gene and core promoter which may be associated with this severe recurrence. The precore/core gene and core promoter of HBV from pre and posttransplantation sera of 15 patients with HBV recurrence were amplified by polymerase chain reaction (PCR) and sequenced. Pre and posttransplant sequences were very similar for each patient. HBV from patients who developed severe recurrence had significantly more mutations in both the nucleotide (P < .05) and predicted amino acid (P < .05) sequences of the precore/core gene, but not in the core promoter, than virus from patients with mild recurrence. There was also an apparent link between severe disease and HBV strains of genotype D (P < .05). The number of nucleotide and amino acid mutations in the precore/core gene was strongly associated with the presence of the precore mutation (P < .01). Mutations were found throughout the entire gene, however, at the amino acid level clustering was observed in the B- and helper T-cell epitopes as well as nuclear localization signals. In the encapsidation signal, nucleotide mutations were found that were predicted to increase the stability of the stem-loop structure. Overall, our data shows that genotype D and accumulated mutations throughout the HBV precore/core gene, but not core promoter, were associated with severe recurrent disease posttransplantation. These mutations were strongly linked to the presence of the precore mutation at nucleotide position 1896 and may contribute to the poor outcome in these patients.

Effect of immunosuppressive and antiviral agents on hepatitis B virus replication in vitro.

Hepatitis B virus (HBV) DNA-transfected hepatoma cells were incubated with the immunosuppressive agents prednisolone, azathioprine, and cyclosporin A (CsA) and the antiviral agents ganciclovir and foscarnet to investigate the effects of these compounds on HBV replication. Prednisolone and azathioprine increased intracellular viral DNA and RNA levels approximately twofold and fourfold, respectively. Treatment with CsA did not alter the levels of viral RNA or DNA. A combination of all three immunosuppressive agents increased the level of intracellular viral DNA eightfold, indicating an additive effect. Incubation of the cells in the presence of foscarnet decreased levels of both single-stranded and relaxed circular viral DNA, and in the presence of ganciclovir decreased the levels of relaxed circular viral DNA, predictable effects from their known mechanism of action. The stimulatory effect on viral replication induced by the combination of immunosuppressive agents was substantially inhibited by ganciclovir-foscarnet treatment. These observations could have implications for the management of recurrent HBV infection after liver transplantation.

Hepatitis B virus precore mutant infection is associated with severe recurrent disease after liver transplantation.

The factors that predispose patients undergoing liver transplantation for hepatitis B virus (HBV) disease to severe recurrence of infection are unclear. In this study we examined the effect of pretransplantation infection with HBV and precore variant strains of HBV on posttransplantation outcome and allograft histology in 24 patients who survived more than 3 months after liver transplantation. Based on pretransplantation serum HBV DNA status as detected by the polymerase chain reaction (PCR) and direct sequencing, the 24 patients could be assigned to three groups. In group 1 there were 4 patients HBV DNA-negative before transplantation and none of these patients suffered recurrence of infection posttransplantation. In group 2, of 10 patients with pretransplantation infection with wild-type virus, 7 became reinfected, and 1 of these developed HBV-related graft failure. In group 3, 9 of 10 patients infected with precore mutant HBV strains became reinfected. However, in contrast to the patients in group 2, 7 patients in group 3 developed HBV-related graft loss, and 5 of these patients had fibrosing cholestatic hepatitis (FCH). These results indicate that infection with precore mutant strains of HBV predisposes a patient to early graft loss following transplantation.

The office of the coroner.

Society has always been concerned about deaths which do not result from natural causes. In Canada, provincial legislatures have met this concern with legislation known as the Coroners' Act in some provinces and as the Fatality Inquiries Act in others. While these statutes are not identical, their intent is the same: to ensure that all unusual deaths are fully investigated to determine their true cause. The coroner's or medical examiner's primary responsibility is to show the public how similar deaths may be avoided.