Anorexia nervosa subtypes: differences in recovery.
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Analysis of Variance↗
Biomedical subjects
Nigel Brown
Publications and source records attributed to Nigel Brown.
Estrogen administration does not reduce the rate of recurrence of affective psychosis after childbirth.
BACKGROUND: High rates of postpartum relapse occur in women with histories of bipolar or schizoaffective disorder. These relapses may be triggered by the postdelivery fall in circulating estrogen through alteration of central neurotransmitter (especially dopaminergic) systems. This study tested the hypothesis that estrogen administration after childbirth would prevent postpartum relapse and would alter dopamine receptor sensitivity. METHOD: Twenty-nine pregnant women with a Research Diagnostic Criteria diagnosis of hypomania (bipolar II), mania (bipolar I), or schizoaffective disorder participated in an open clinical trial. Three transdermal dose regimens of estrogen (17beta-estradiol) were tested. Starting doses were 200 (N = 13), 400 (N = 3), and 800 (N = 13) micro g/day, beginning within 48 hours after delivery and reduced by one half every 4 days for a total of 12 days. On the fourth day after starting estradiol therapy (before relapse occurred), subjects participated in a neuroendocrine challenge test that measured the sensitivity of the central nervous system (tubero-infundibular) dopaminergic system (plasma prolactin and growth hormone responses to apomorphine). RESULTS: Estradiol at all dose regimens did not reduce the rate of relapse. However, of the 12 women who relapsed, those who had taken the highest dose of estradiol (800 micro g/day) needed less subsequent psychotropic medication (fewer chlorpromazine equivalents) and were discharged sooner than those who had taken either of the 2 lower doses. No differences in neuroendocrine responses to apomorphine were detected between women receiving the high-dose and the lower-dose regimens. CONCLUSION: The results do not support the hypothesis that a fall in circulating concentrations of estrogens precipitates relapse in subjects at risk of postpartum affective psychosis. The use of prophylactic estrogen in such circumstances is therefore highly questionable.
Administration, Cutaneous↗
[The mouse as a model for heart morphogenesis in mammals: the origin of myocytes and studies with cardiac explants].
The heart is one of the first organs to form during embryogenesis since its circulatory function is critical from early stages for embryo survival. In man, morphological events are affected by molecular perturbations, which can lead to a congenital heart defect. It is important therefore to understand not only the molecular signals, but also the morphological events, which govern myocardial cell identity. The study of transgenic mouse lines, Mlc1v-nlacZ-24 and Mlc3f-nlacZ-2, has led to the identification of a new precardiac territory, the anterior heart field, which has also been described recently in birds, and which contributes to the myocardium of the arterial pole of the heart. The use of explant cultures also indicates that pharyngeal mesoderm participates in the formation of the outflow tract and right ventricle and shows that the primitive heart tube has a predominantly left ventricular identity. We have also shown that Fgf-10 is expressed in the anterior heart field, where a role for FGF signaling in arterial pole morphogenesis is suggested by inhibitor experiments. Finally explant cultures have been employed to examine the acquisition of left-right atrial identity. The Mlc3f-nlacZ-2 line, which marks the right atrium, allowed us to determine the time window during which left-right signaling confers left-right atrial identity.
Animals↗
The ECVAM international validation study on in vitro embryotoxicity tests: results of the definitive phase and evaluation of prediction models. European Centre for the Validation of Alternative Methods.
From 1996 to 2000, ZEBET (Centre for Documentation and Evaluation of Alternative Methods to Animal Experiments at the BgVV, Berlin, Germany) coordinated the European Centre for the Validation of Alternative Methods (ECVAM) prevalidation and validation study on three embryotoxicity tests: a) a test employing embryonic stem cell lines (EST); b) the micromass (MM) test; and c) the postimplantation rat whole-embryo culture assay (WEC test). The main objectives of the study were to assess the performance of these three in vitro tests in discriminating between non- embryotoxic, weakly embryotoxic and strongly embryotoxic compounds. Phase I of the study (1997) was designed as a prevalidation phase, for test protocol optimisation, and for the establishment of a comprehensive database of in vivo and in vitro data on embryotoxic compounds. Phase II (1998-2000) involved a formal validation trial, conducted under blind conditions on 20 test compounds selected from the database, which were coded and distributed to the participating laboratories. In the preliminary phase of the validation study, six chemicals out of the 20, which showed embryotoxic potential, were tested. These results were used to define new biostatistically based prediction models (PMs) for the MM and WEC tests, and to evaluate those developed previously for the EST. As a next step, the PMs were evaluated by using the results for the remaining 14 chemicals of the definitive phase of the validation study. The three in vitro embryotoxicity tests proved to be applicable to testing a diverse group of chemicals with different embryotoxic potentials (non-embryotoxic, weakly embryotoxic, and strongly embryotoxic). The reproducibility of the three in vitro embryotoxicity tests were acceptable according to the acceptance criteria defined by the Management Team. The concordances between the embryotoxic potentials derived from the in vitro data and from the in vivo data were good for the EST and the WEC (PM2) test, and sufficient for the MM test and the WEC (PM1) tests according to the performance criteria defined by the Management Team before the formal validation study. When applying the PM of the EST to the in vitro data obtained in the definitive phase of the formal validation study, chemicals were classified correctly in 78% of the experiments. For the MM and the WEC tests, the PMs provided 70% and 80% (PM2) correct classifications, respectively. And, very importantly, an excellent predictivity (100%, except for PM1 of the WEC test, with 79%, considered as good) was obtained with strong embryotoxic chemicals in each of the three in vitro tests.
3T3 Cells↗