Spectroscopic, radiochemical, and theoretical studies of the Ga3+-N-2-hydroxyethyl piperazine-N'-2-ethanesulfonic acid (HEPES buffer) system: evidence for the formation of Ga3+ - HEPES complexes in (68) Ga labeling reactions.

Recent reports have claimed a superior performance of HEPES buffer in comparison to alternative buffer systems for (67/68) Ga labeling in aqueous media. In this paper we report spectroscopic ((1) H and (71) Ga NMR), radiochemical, mass spectrometry and theoretical modeling studies on the Ga(3+)/HEPES system (HEPES = N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) performed with the aim of elucidating a potential contribution of HEPES in the (68/67) Ga radiolabeling process. Our results demonstrate that HEPES acts as a weakly but competitive chelator of Ga(3+) and that this interaction depends on the relative Ga(3+): HEPES concentration. A by-product formed in the labeling mixture has been identified as a [(68) Ga]Ga(HEPES) complex via chromatographic comparison with the nonradioactive analog. The formation of this complex was verified to compete with [(68) Ga]Ga(NOTA) complexation at low NOTA concentration. Putative chelation of Ga(3+) by the hydroxyl and adjacent ring nitrogen of HEPES is proposed on the basis of (1)H NMR shifts induced by Ga(3+) and theoretical modeling studies.

Changes in the importance of quality of life domains after cancer diagnosis.

The aim of this study was to describe what domains in quality of life were considered most or least important by patients with newly diagnosed cancer and in what way the domains of importance changed during a 9-month period. We also analysed the impact of selected demographic variables on the important domains. The Ferrans' and Powers' Quality of Life Index was used to measure quality of life. As this index consists of one section measuring the importance of various domains of life, information about changing standards was available. The study sample consisted of 131 adult patients recently diagnosed with different cancers. The whole sample filled in the questionnaire once, while part of the sample (n = 41) filled it in four times during a 9-month period. Items related to family matters were rated as most important, while faith in God was reported to be of least importance. The patients fluctuated somewhat in terms of what was most important to them during the study period. Overall, the most unstable items tended to be less important over time. In addition, results showed significant differences in the importance of quality of life domains according to gender, age, educational level and cohabitation.

[Value of the Hannover Intensive Score (HIS) in internal medicine intensive care]. / Die Aussagekraft des Hannover Intensiv Score (HIS) in der internistischen Intensivmedizin.

BACKGROUND AND OBJECTIVES: Scoring systems are important tools for quality control and stratification of study populations in intensive care medicine. The study aims to systematically evaluate predictive ability and severity classification ability of the combined physiologic-therapeutic Hannover Intensiv Score (HIS). Such data are not existing regarding medical intensive care medicine. METHODS: 1060 consecutive patients (ICU stay > 4 hours) being admitted to a medical ICU were prospectively investigated. HIS was determined for all patients each day during ICU stay. The results were compared to the physiologically based APACHE II and to the therapeutically based TISS, which both were determined as well. RESULTS: HIS provided sufficient discrimination between survival and nonsurvival [hospital mortality; area under the ROC curve (AUC) = 0.822] with no significant differences compared to APACHE II (AUC = 0.838) and TISS (AUC = 0.798), respectively. During longer course of ICU stay HIS offers better outcome prognostication compared to the unilateral systems with respect to specificity and total correct classification rate. There was a nearly linear increase of hospital mortality with an increase of day-1-HIS. The same was observed with APACHE II and TISS. Mean day-1-scores for survivors were significantly higher compared to non-survivors with all systems (p < 0.0001). Day-1-HIS moderately correlates with both other systems (APACE II: r = 0.766; TISS: r = 0.814). CONCLUSIONS: The Hannover Intensiv Score as a model of a combined physiologic-therapeutic scoring system was successfully validated concerning hospital outcome prediction and severity of disease classification in a large medical ICU population. Thus, for these applications it can be used in similar German ICUs. A main argument for applying the system is the employment of a fairly small set of easily accessible parameters.

[Online measurement of retinal artery branches in type II diabetic patients. Initial clinical trials before and after laser coagulation]. / Online-Messung retinaler Arterienäste bei Typ-II-Diabetikern. Erste klinische Versuche vor und nach fokaler Laserkoagulation.

UNLABELLED: By the use of a new online measuring system the effect of argon-laser coagulation in diabetics on the diameters of retinal arteries was measured. METHOD: The vessel diameter of retinal branch arteries were measured in patients with type-II diabetes before and after (0.5 h) argon-laser coagulation. Ten patients without previous laser treatment were included in this study. Measurements were taken in all four quadrants by the use of a new automatic online measuring system. RESULTS: The new technique allowed measurements to be made within an acceptable period of time and with little strain on patients. After argon-laser coagulation 56.7% of retinal arteries showed a significant vasodilation. No significant changes in vessel diameter were found in 18.9% of these arteries, whereas 24.3% showed significant vasoconstriction. CONCLUSION: The new online measuring system is able to measure the effects of photocoagulation on an individual basis with a noninvasive technique. The first findings presented here confirm previous studies of larger groups, with a considerable reduction in efforts required.

[Adaptive procedures for measuring arterial blood flow velocity in retinal vessels using indicator technique]. / Adaptive Verfahren zur Messung arterieller Blutgeschwindigkeiten in Netzhautgefässen mittels Indikatortechnik.

There are highly significant differences in the measuring results of arterial blood velocity between the indicator and laser-Doppler techniques (up to 800%). A new measuring procedure for the analysis of indicator dilution curves was developed based on indicator model and experimental results. The use of this new measuring procedure results in reduced mean systematic error between the indicator and laser-Doppler techniques to values around 10%. With the introduction of adaptive measuring arrays for the creation of indicator dilution curves and the application of adaptive algorithms for centering and spectral normalizing of the dilution curves, improved reproducibility can be expected.

A new approach for detecting the position of retinal vessels and calculating their diameter on the basis of dynamic spectral analysis.

Fast adaptive algorithms were used for the detection of retinal vessels and for pre-processing the signals. By using different methods of dynamic spectral analysis, the local frequency of the vessels was determined. On this basis a method of calculating the diameters of the vessels was constructed; it is robust in relation to disturbances in the domain of the edges.

Filtering properties of an adaptive trend operator and the application for determining the arterial blood velocity in retinal vessels.

This study deals with methods focused on estimating blood velocity. The estimation of the linear trend function of a non-stationary signal based on the adaptive recursive estimation of the mean value function is used for the determination of the time delay of two indicator dilution curves. The filter property of this trend operator depends on the choice of a constant parameter c, the so-called adaptation factor. The functional connection between the filter property and the adaptation factor is considered in such a way that an objective calculation of arterial blood velocity in retinal vessels is possible.