Effects of loperamide on the human hypothalamo-pituitary-adrenal axis in vivo and in vitro.

Loperamide, an opiate agonist of high specificity for p-receptors, was recently reported to suppress ACTH and cortisol levels in normal subjects, but not in patients with proven ACTH-dependent Cushing’s disease. However, there is little information on the site of action of loperamide in the hypothalamo-pituitary-adrenal axis of man. We investigated the effect of loperamide on pituitary hormone secretion in uiuo and in vitro. In seven normal subjects, basal ACTH plasma levels were significantly suppressed 3 h after loperamide administration (16 mg, orally) from 5 + 1 to 2 f 0 pmol/L (P < 0.0001). After the combined pituitary stimulation test (100 pg human CRH, 100 rg GnRH, 100 pg GH-releasing hormone, and 200 pg TRH), the ACTH peak (maximum increase at 30 min) was significantly blunted by loperamide from 9 + 1 to 4 of: 1 pmol/L (P < 0.001) and the area under the curve of ACTH from O-120 min was reduced from 35 + 5 to 23 + 4 pmol/L.2 h (P < 0.05). In the insulin-hypoglycemia test (0.15 IU/kg BW), neither the ACTH peak nor the area under the curve of ACTH was affected by loperamide. In six patients with Cushing’s disease and one patient with secondary adrenal insufficency due to hypothalamic failure, neither basal ACTH and cortisol levels nor CRH-stimulated levels were influenced by loperamide. In four cultured human corticotropic adenomas, loperamide was not able to reduce basal and CRH-induced ACTH secretion. In summary, loperamide is able to reduce basal and CRHinduced ACTH and cortisol levels in normal subjects, but not in patients with Cushing’s disease or secondary adrenal failure of hypothalamic origin. Loperamide has no significant effect on insulin-hypoglycemia- induced ACTH and cortisol levels and, therefore, no effect on stress-induced elevation of cortisol levels. Loperamide might act at a suprapituitary site in man in viuo, but, nevertheless, a pituitary site cannot be excluded

Chiral 1D Floquet topological insulators beyond rotating wave approximation

We study one-dimensional (1D) Floquet topological insulators with chiral symmetry going beyond the standard rotating wave approximation. The occurrence of many anticrossings between Floquet replicas leads to a dramatic extension of phase diagram regions with stable topological edge states (TESs). We present an explicit construction of all TESs in terms of a truncated Floquet Hamiltonian in frequency space, prove the bulk-boundary correspondence, and analyze the stability of the TESs in terms of their localization lengths. We propose experimental tests of our predictions in curved bilayer graphene.Comment: 4+9 page

Spin dynamics in the Kapitza-Dirac effect

Electron spin dynamics in Kapitza-Dirac scattering from a standing laser wave of high frequency and high intensity is studied. We develop a fully relativistic quantum theory of the electron motion based on the time-dependent Dirac equation. Distinct spin dynamics, with Rabi oscillations and complete spin-flip transitions, is demonstrated for Kapitza-Dirac scattering involving three photons in a parameter regime accessible to future high-power X-ray laser sources. The Rabi frequency and, thus, the diffraction pattern is shown to depend crucially on the spin degree of freedom

An evaluation of the German teacher version of the Developmental Behaviour Checklist in children and adolescents with intellectual disability

BACKGROUND The Developmental Behaviour Checklist (DBC) is an established, internationally used questionnaire for assessing behavioural and emotional problems among young people with developmental or intellectual disabilities (ID). The present study aims to evaluate the psychometric properties of its German teacher version (DBC-T). METHOD The German DBC-T was administered to 397 school staff members who reported twice on 1177 children and adolescents with ID over a period of 7–9 months. Data were analysed within an exploratory structural equation modelling framework. RESULTS Our results supported the five-factor structure of the DBC-T and found good reliability for all scales. Analyses on the relationship of DBC-T scores with students’ age, gender, and adaptive behaviour provided further evidence for the validity of the DBC-T. CONCLUSIONS Our study endorses the notion that the German DBC-T is an important instrument both for research and practice. Limitations and further directions are discussed

Modified toggle pin technique combined with prosthetic capsular reconstruction for surgical stabilization of coxofemoral luxation in a Shetland pony

Objective To describe open reduction and surgical stabilization of a coxofemoral luxation in a pony using a modified toggle pin technique and prosthetic joint capsule reconstruction without osteotomy of the greater trochanter. Animal A 2-year-old Shetland pony with a bodyweight of 167 kg. Study design Case report. Methods Radiographic examination confirmed craniodorsal luxation of the left coxofemoral joint. An open reduction with the aid of a pulley system was performed. A toggle pin was inserted through a bone tunnel extending from the level of the femoral shaft through the femoral head and the center of the acetabulum for the pin to be positioned on the medial wall of the acetabulum. FiberWire was subsequently passed through the cranial and caudal aspects of the acetabulum as well as a transverse tunnel in the femoral neck in a figure of 8 to facilitate capsular reconstruction. The pony was placed in a sling for 8 weeks and gradually returned to normal activity over 2 months. Results Postoperative radiographic examination confirmed the position of the femoral head in the acetabulum with the implants in place. On 2-year follow-up the pony was sound at walk and trot. Conclusion A combined intra- and extra-articular stabilization technique for coxofemoral luxation in a pony resulted in successful long-term reduction and excellent outcome

Pair production in laser fields oscillating in space and time

The production of electron-positron pairs from vacuum by counterpropagating laser beams of linear polarization is calculated. In contrast to the usual approximate approach, the spatial dependence and magnetic component of the laser field are taken into account. We show that the latter strongly affects the creation process at high laser frequency: the production probability is reduced, the kinematics is fundamentally modified, the resonant Rabi-oscillation pattern is distorted and the resonance positions are shifted, multiplied and split.Comment: 5 pages, 5 figure