Über die Spaltung herzwirksamer Glykoside im Tierkörper

Ohne ZusammenfassungMit 3 TextabbildungenAusgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.Ausführliche Wiedergabe der Versuchsprotokolle in der Dr.-Dissertation Ruth Engler, Frankfurt a. M. 1958.     

Social stress and T cell maturation in male rats: transient and persistent alterations in thymic function

The present study demonstrates that social stress in subordinate male rats resulting from a 24-h confrontation with a dominant male opponent caused not only transient but also persistent alterations in the function and the cellular composition of the thymus. The investigation of regulation processes maintaining tissue homeostasis in the thymus showed a significant increase in apoptosis, a decrease in cellular proliferation and a decrease in thymic export as indicated by a reduction in the number of recent thymic emigrants (RTE) in the peripheral blood. The proliferative response of mature thymocytes to Concanavalin A (ConA) was also significantly reduced in socially defeated rats. Adrenalectomy (ADX) completely abolished the stress-associated alterations in thymic function whereas a decrease in total thymocyte numbers was still evident in defeated animals treated with the glucocorticoid type-II receptor antagonist RU486. The significant reduction in total thymocytes and the diminished proliferative response to ConA persisted for at least seven days after stressor cessation. An enhanced proliferative activity at this point of time may represent a beginning regeneration of thymic tissue after stress. Taken together, our studies show that social stress profoundly disturbs tissue homeostasis in the thymus and suggest that adrenal-derived hormones play a central role in mediating this effect. The strong positive relationship between total thymocyte numbers and peripheral RTE numbers and the long-lasting atrophy of the thymus in defeated animals may suggest negative consequences for the heterogeneity of naïve T cells in the peripheral T cell pool after social stress.     

Using a structured medical note for determining the safety profile of anthrax vaccine for US soldiers in Korea

Selected military personnel are immunized with an FDA-licensed anthrax vaccine unless there are clinical contraindications. The objective of this analysis is to capture the experience of soldiers receiving anthrax vaccine to assist in better patient-provider communication and clarify the safety profile of the vaccine in this population as a quality-assurance initiative. Between August 1998 and July 1999, 2824 soldiers immunized against anthrax at one military clinic completed a structured medical note that was reviewed by a clinician. Female gender, prior vaccine-associated adverse events, and medication use were significantly related to higher reports of adverse events. All reported immediate consequences resolved.     

Acute presentations of renal artery stenosis in three patients with a solitary functioning kidney

Renal artery stenosis can present uncommonly in the acute state as flash pulmonary oedema and hypertensive encephalopathy. We present three such cases in patients with a solitary functioning kidney, with successful management via renal artery angioplasty and stent insertion.     

Docosahexaenoic acid--induced vasorelaxation in hypertensive rats: mechanisms of action

The authors investigated the vasorelaxant properties of the omega-3 fatty acid, docosahexaenoic (DHA, 22:6n-3), and the possible involvement of endothelium-derived nitric oxide, prostanoids, opening of K+ channels, and/or modulation of calcium-mediated events. Isolated aorta from male spontaneously hypertensive rats (SHR) (age 16-17 weeks) were used to measure isometric tension. DHA-induced (1-100 mumol/l) relaxation was examined following contraction to norepinephrine (NE) (10(-6) mol/l) or high-K+ (80 mmol/l) solution in the presence and absence of various inhibitors and calcium-containing solution. DHA acid induced a significant vasorelaxant effect in both NE and high-K(+)-induced contracted SHR aortic rings, although DHA relaxations were greater in high-K(+)-induced contracted rings. In the absence of extracellular calcium, DHA (5-30 mumol/l) inhibited the initial phasic and sustained components of NE-induced contraction under different conditions. Inhibition of nitric oxide synthesis by N omega-nitro-L-arginine methyl ester hydrochloride (100 mumol/l) had no effect on DHA relaxations; however, indomethacin or nifedipine caused significant inhibition at > or = 30 mumol/l DHA. The K+ channel blocker, glibenclamide, but not tetraethyl-ammonium, also had an inhibitory effect on DHA-induced relaxation. These results indicate that DHA's vasorelaxant actions in SHR aorta are independent of endothelium-derived nitric oxide; however, at DHA concentrations > or = 30 mumol/l, vasodilatory prostanoids that activate ATP-sensitive K+ channels (KATP) may be involved. At lower concentrations, DHA-induced relaxation appears to be attributed to modulation of intracellular Ca2+ release and L-type Ca2+ channels in vascular smooth muscle cells. The vasorelaxant properties of DHA may contribute, in part, to the blood pressure-lowering effect of dietary fish oil in this hypertensive model.     

Endovascular treatment of arterial mesenteric ischaemia: A retrospective review

Mesenteric ischaemia is a condition that has traditionally been managed surgically. It poses a challenging diagnostic and therapeutic problem, particularly in the acute setting. We review a small series of eight patients managed with endovascular techniques for either acute or chronic mesenteric ischaemia at The Royal Melbourne Hospital, from 1997 to 2002. We describe our results and relate these to the recent published literature regarding endovascular and surgical management of mesenteric ischaemia. Our experience confirms the valuable contribution of angioplasty and stenting in chronic mesenteric ischaemia, which compares favourably with surgery with regards to complication rates and mortality. We suggest the need for further studies to compare the long‐term efficacy of endovascular techniques compared with surgery in the management of chronic mesenteric ischaemia. Furthermore, we demonstrate a role for endovascular management in acute mesenteric ischaemia, in the appropriate clinical setting.     

Dosimetric Verification of the Dynamic Intensity-Modulated Radiation Therapy of 92 Patients

Purpose: To verify that optimized dose distributions provided by an intensity-modulated radiation therapy (IMRT) system are delivered accurately to human patients.

Methods and Materials: Anthropomorphic phantoms are used to measure IMRT doses. Four types of verification are developed for: I) system commissioning with beams optimized to irradiate simulated targets in phantoms, II) plans with patient-optimized beams directed to phantoms simulating the patient, III) patient–phantom hybrid plans with patient-optimized beams calculated in phantom without further optimization, and IV) in vivo measurements. Phantoms containing dosimeters are irradiated with patient-optimized beams. Films are scanned and data were analyzed with software. Percent difference between verified and planned maximum target doses is defined as “dose discrepancy” (Δ_vp). The frequency distribution of type II Δ_vp from 204 verification films of 92 IMRT patients is fit to a Gaussian. Measurements made in vivo yield discrepancies specified as Δ_ivp, also fit to a Gaussian.

Results and Discussion: Verification methods revealed three systematic errors in plans that were corrected prior to treatment. Values of |Δ_vp| for verification type I are <2%. Type II verification discrepancies are characterized by a Gaussian fit with a peak 0.2% from the centroid, and 158 |Δ_vp| <5%. The 46 values of |Δ_vp| >5% arise from differences between phantom and patient geometry, and from simulation, calculation, and other errors. Values of |Δ_vp| for verification III are less than half of the values of |Δ_vp| for verification II. A Gaussian fit of Δ_ivp from verification IV shows more discrepancy than the fit of Δ_vp, attributed to dose gradients in detectors, and exacerbated by immobilization uncertainty.

Conclusions: Dosimetric verification is a critical step in the quality assurance (QA) of IMRT. Hybrid Verification III is suggested as a preliminary quality standard for IMRT.