Spin-orbit coupling of light in asymmetric microcavities

When spinning particles, such as electrons and photons, undergo spin-orbit coupling, they can acquire an extra phase in addition to the well-known dynamical phase. This extra phase is called the geometric phase (also known as the Berry phase), which plays an important role in a startling variety of physical contexts such as in photonics, condensed matter, high-energy and space physics. The geometric phase was originally discussed for a cyclically evolving physical system with an Abelian evolution, and was later generalized to non-cyclic and non-Abelian cases, which are the most interesting fundamental subjects in this area and indicate promising applications in various fields. Here, we enable optical spin-orbit coupling in asymmetric microcavities and experimentally observe a non-cyclic optical geometric phase acquired in a non-Abelian evolution. Our work is relevant to fundamental studies and implies promising applications by manipulating photons in on-chip quantum devices.

Positron emission mammography in the diagnosis of breast cancer. Is maximum PEM uptake value a valuable threshold for malignant breast cancer detection?

AIM

To evaluate the diagnostic value (sensitivity, specificity) of positron emission mammography (PEM) in a single site non-interventional study using the maximum PEM uptake value (PUVmax).

PATIENTS, METHODS

In a singlesite, non-interventional study, 108 patients (107 women, 1 man) with a total of 151 suspected lesions were scanned with a PEM Flex Solo II (Naviscan) at 90 min p.i. with 3.5 MBq 18F-FDG per kg of body weight. In this ROI(region of interest)-based analysis, maximum PEM uptake value (PUV) was determined in lesions, tumours (PUVmaxtumour), benign lesions (PUVmaxnormal breast) and also in healthy tissues on the contralateral side (PUVmaxcontralateral breast). These values were compared and contrasted. In addition, the ratios of PUVmaxtumour / PUVmaxcontralateral breast and PUVmaxnormal breast / PUVmaxcontralateral breast were compared. The image data were interpreted independently by two experienced nuclear medicine physicians and compared with histology in cases of suspected carcinoma.

RESULTS

Based on a criteria of PUV>1.9, 31 out of 151 lesions in the patient cohort were found to be malignant (21%). A mean PUVmaxtumour of 3.78 ± 2.47 was identified in malignant tumours, while a mean PUVmaxnormal breast of 1.17 ± 0.37 was reported in the glandular tissue of the healthy breast, with the difference being statistically significant (p < 0.001). Similarly, the mean ratio between tumour and healthy glandular tissue in breast cancer patients (3.15 ± 1.58) was found to be significantly higher than the ratio for benign lesions (1.17 ± 0.41, p < 0.001).

CONCLUSION

PEM is capable of differentiating breast tumours from benign lesions with 100% sensitivity along with a high specificity of 96%, when a threshold of PUVmax >1.9 is applied.

Direct X-Ray Study of the Molecular Tilt in Dipalmitoyl Lecithin Bilayers

Direction and angle of molecular tilt in an ordered multilayer system of dipalmitoyl lecithin and water were directly determined by X-ray diffraction as a function of temperature in the gel phase with ca. 20 wt. % of water

Abstract P4-01-24: Positron emission mammography (PEM) does increase specificity in diagnosis of breast cancer

Purpose:

To determine the diagnostic performance of PEM, a HR-PET with intrinsic resolution of 1.6 mm in detection of breast cancer (B-Ca).

Methods and Material:

PEM was performed in 122 lesions with suspicious breast lesions 90 min after i.v. application of 3.5 MBq F-18-FDG per KG body weight. A ROI marked the target lesion, measured the maximum PEM uptake value (PUVmax) and was correlated with a corresponding non-target ROI in the contra lateral healthy breast determining the target/non-target ratio. Two independent readers analysed images of all 122 lesions and compared the results to histopathology (11 PEM-Biopsies/8 Breast-Cancers) later. The group analyses for all malignant, benign, corresponding non-target lesions and the mean target/non-target ratio were calculated by paired Student t-Test.

Results:

22 out of 122 lesions were malignant. Mean of PUVmax was measured 4.3±2,7 in malignant lesions and 1.1±0.4 for the contra-lateral healthy breast (p = 0.001). The mean target/non-target ratio in patients with B-Ca of 3.7±1.5 was also significantly higher compared to benign lesions 1.1±0.4 (p = 0.001).

Considering a PUVmax &gt;1.9, PEM was true-positive in all 22 cancers resulting in a sensitivity of 100%, specificity of 97%, PPV of 88% and NPV of 100%.

Detecting of B-Ca by PEM was at it´s best observed with a PUVmax cut-off level of &gt;1.9 combined with a target/non-target ratio of &gt;1.4.

Conclusion:

PEM can detect breast cancer with high accuracy using PUVmax as well as target/non-target ratio with high specificity. The results shown have to be confirmed in larger patient cohort. The higher specificity causes a lower rate of biopsies, surgery, chemotherapy and costs, therefore a evidence based medicine study will start in Germany.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-24.

False-positive radio-iodinated metaiodobenzylguanidine (123I-MIBG) accumulation in a mast cell-infiltrated infantile haemangioma

Radio-iodinated metaiodobenzylguanidine ((123)I-MIBG) is used for the detection and staging of neuroblastoma, pheochromcytoma and other neuroendocrine tumours in diagnostic nuclear medicine. A specific uptake and storage mechanism provides the basis for imaging with (123)I-MIBG. Nevertheless, cases of false-positive (123)I-MIBG scintigraphy with accumulation in non-chromaffin tumours have been described. Here, we present a case of a false-positive (123)I-MIBG scan in a case of a mast-cell infiltrated infantile haemangioma and discuss the possible uptake mechanism.

Impact of FDG-PET for staging of oesophageal cancer

BACKGROUND AND AIMS

Treatment of oesophageal cancer depends on staging and the general health of the patient. In stages I-II b, as well as in some stage III diseases, surgical resection remains the therapy of choice for cure, but a curative approach is not possible in stage IV. In our hospital we give preoperative radio-chemotherapy to all patients with an oesophageal cancer T>1, Nx, M0. Therefore, the main purpose of the clinical staging of oesophageal cancer is the exclusion of M1 and T4 disease with infiltration into the tracheobronchial system or the aorta. The aim of the investigation was the assessment of positron emission tomography for detection of M1 disease.

PATIENTS/METHODS

Between 1998 and 2002, 84 patients with oesophageal cancer (64% squamous cell carcinoma and 36% adenocarcinoma) were enrolled into the study. Of these, 48.8% were operated on; 35.7% of the patients were not operated on, for oncological reasons, 7.1% for medical reasons, 3.6% chose not to be operated on, and, for unknown reasons, 4.8% were not operated on.

RESULTS

Twenty-five patients had stage IV disease or additional, synchronous cancer of the head and neck ( n=2). As the only investigational procedure, positron emission tomography revealed M1 stage in 11 of 25 patients (44%). In 13/25 (52%) both computed tomography and positron emission tomography revealed stage IV disease. False positive results by positron emission tomography were observed in three patients. The sensitivity and specificity of positron emission tomography (PET) was 0.96 and 0.95, respectively. Most of the metastases detected by PET only, were localised within the neck, liver and bone. With regard to the 66 of 84 patients deemed medically fit for operation and without local infiltration into the tracheobronchial system (T4) PET as the only imaging procedure changed the therapeutic strategy in 11 of 66 (16.6%) patients with to M1 disease.

CONCLUSION

Our results demonstrated clearly the impact of the PET scan for decision-making in patients with oesophageal carcinoma. PET should be performed prior to therapy with curative intention. However, addition of a computed tomography scan of the neck might reduce the rate of unexpected metastases detected by PET.

Effects of neoadjuvant radio-chemotherapy on 18F-FDG-PET in esophageal carcinoma

AIM

To investigate whether results of [F-18]-fluorodeoxy-d-glucose (FDG) positron emission tomography (PET) of esophageal cancer (EC) before and after neoadjuvant radio-chemotherapy correlate with histopathology after esophageal resection.

METHODS

Twenty consecutive patients with EC without distant metastases were examined twice with 18F-FDG-PET during primary staging and after neoadjuvant radio-chemotherapy. FDG standardised uptake values (SUV) were correlated with the histopathological findings (percentage of viable tumour cells, tumour regression grade 1-5).

RESULTS

Regression analysis revealed a slight (not significant) positive correlation between SUV(pre) (R=0.41, p=0.08) and SUV(post) (R=0.37, p=0.11) and the percentage of viable tumour cells in the resectate. Although all patients showed a significant decrease in SUV after radio-chemotherapy (p < 0.01) the percentual decrease of the SUV after therapy (DeltaSUV%) did not significantly differ between the TRG-groups. In 12 of 20 patients (60%), therapy-induced esophagitis was detected in post-therapeutic PET images.

CONCLUSION

In EC, a higher pre-therapeutic SUV might be correlated with a higher fraction of vital tumour cells remaining after radio-chemotherapy. Applying the neoadjuvant therapy protocol and the study design used in this examination, there is no correlation between decrease in SUV and histopathology.

Identification of aggregates of magnetic nanoparticles in ferrofluids at low concentrations

Different very dilute suspensions of magnetic nanoparticles (magnetite surrounded by an organic shell) in water (ferrofluids) were investigated using small-angle X-ray scattering. It is shown that the scattering originates not only from noncorrelated core–shell nanoparticles, but also from larger structures. By modelling, these structures can be identified as close-packed clusters consisting of core–shell particles (core diameter ∼10 nm). The analysis of the radial distance distribution function, obtained by Fourier transformation of the scattered intensity, reveals a lower bound of the mean cluster size of about 40 nm. The formation of clusters is persistent, even in very dilute suspensions.

Attosecond control of electronic processes by intense light fields

The amplitude and frequency of laser light can be routinely measured and controlled on a femtosecond (10(-15) s) timescale. However, in pulses comprising just a few wave cycles, the amplitude envelope and carrier frequency are not sufficient to characterize and control laser radiation, because evolution of the light field is also influenced by a shift of the carrier wave with respect to the pulse peak. This so-called carrier-envelope phase has been predicted and observed to affect strong-field phenomena, but random shot-to-shot shifts have prevented the reproducible guiding of atomic processes using the electric field of light. Here we report the generation of intense, few-cycle laser pulses with a stable carrier envelope phase that permit the triggering and steering of microscopic motion with an ultimate precision limited only by quantum mechanical uncertainty. Using these reproducible light waveforms, we create light-induced atomic currents in ionized matter; the motion of the electronic wave packets can be controlled on timescales shorter than 250 attoseconds (250 x 10(-18) s). This enables us to control the attosecond temporal structure of coherent soft X-ray emission produced by the atomic currents--these X-ray photons provide a sensitive and intuitive tool for determining the carrier-envelope phase.

[Appropriate uptake period for myocardial PET imaging with 18F-FDG after oral glucose loading]

AIM

Identification of a rationale for the appropriate uptake period for myocardial (18)F-FDG-PET imaging of patients with and without diabetes mellitus.

METHODS

In a subset of 27 patients, static 2D-PET examination was performed of patients with chronic coronary artery disease and known myocardial infarction. The patients fasted (at least 4 h) before examination. (18)F-FDG (330 +/- 20 MBq) was injected intravenously. The image quality was semiquantitativly determined by ROI-analysis and the myocardium-to-blood pool activity ratio (M/B) was calculated. I.) Scans 30, 60, and 90 min p. i. of 10 non-diabetic patients (60 g oral glucose loading one hour before FDG-injection, low-dose intravenous insulin bolus if necessary). II.) Scans 30, 60, and 90 min p. i. of 10 patients with known non-insulin dependent diabetes (20 g glucose, insulin bolus). III.) Scans 90 min p. i. of 7 patients with known non-insulin dependent diabetes and elevated fasting serum glucose level (140-200 mg/dl; insulin bolus, no glucose).

RESULTS

I.) The M/B ratio significantly increases in nondiabetic patients with the uptake time (30 min 1.95 +/- 0.20; 60 min 2.96 +/- 0.36; 90 min 3.78 +/- 0.43). II.) In patients with non-insulin dependent diabetes the M/B ratio also significantly increases with uptake time. Compared to non-diabetic patients group II reached smaller M/B values (30 min 1.56 +/- 0.10; 60 min 2.15 +/- 0.14; 90 min 2.71 +/- 0.19). III.) In the group of patients with elevated fasting serum glucose level (who only got insulin but no glucose loading) the M/B activity ratio 90 min p. i. was clearly inferior compared with diabetic patients after oral glucose loading and insulin administration (M/B 2.71 +/- 0.19 versus 2.16 +/- 0.07).

CONCLUSIONS

In static myocardial viability PET studies with (18)F-FDG an uptake time of 90 min yields image quality superior to that obtained after shorter uptake time.

Optimaler Akquisitionszeitpunkt für die Herz-PET mit 18F-FDG nach oraler Glukosebelastung

Aim: Identification of a rationale for the appropriate uptake period for myocardial 18F-FDG-PET imaging of patients with and without diabetes mellitus. Methods: In a subset of 27 patients, static 2D-PET examination was performed of patients with chronic coronary artery disease and known myocardial infarction. The patients fasted (at least 4 h) before examination. 18F-FDG (330 ± 20 MBq) was injected intravenously. The image quality was semiquantitativly determined by ROI-analysis and the myocardium-to-blood pool activity ratio (M/B) was calculated. I.) Scans 30, 60, and 90 min p. i. of 10 non-diabetic patients (60 g oral glucose loading one hour before FDG-injection, low-dose intravenous insulin bolus if necessary). II.) Scans 30, 60, and 90 min p. i. of 10 patients with known non-insulin dependent diabetes (20 g glucose, insulin bolus). III.) Scans 90 min p. i. of 7 patients with known non-insulin dependent diabetes and elevated fasting serum glucose level (140-200 mg/dl; insulin bolus, no glucose). Results: I.) The M/B ratio significantly increases in non-diabetic patients with the uptake time (30 min 1.95 ± 0.20; 60 min 2.96 ± 0.36; 90 min 3.78 ± 0.43). II.) In patients with non-insulin dependent diabetes the M/B ratio also significantly increases with uptake time. Compared to non-diabetic patients group II reached smaller M/B values (30 min 1.56 ± 0.10; 60 min 2.15 ± 0.14; 90 min 2.71 ± 0.19). III.) In the group of patients with elevated fasting serum glucose level (who only got insulin but no glucose loading) the M/B activity ratio 90 min p. i. was clearly inferior compared with diabetic patients after oral glucose loading and insulin administration (M/B 2.71 ± 0.19 versus 2.16 ± 0.07). Conclusions: In static myocardial viability PET studies with 18F-FDG an uptake time of 90 min yields image quality superior to that obtained after shorter uptake time.

Time-resolved atomic inner-shell spectroscopy

The characteristic time constants of the relaxation dynamics of core-excited atoms have hitherto been inferred from the linewidths of electronic transitions measured by continuous-wave extreme ultraviolet or X-ray spectroscopy. Here we demonstrate that a laser-based sampling system, consisting of a few-femtosecond visible light pulse and a synchronized sub-femtosecond soft X-ray pulse, allows us to trace these dynamics directly in the time domain with attosecond resolution. We have measured a lifetime of 7.9(-0.9)(+1.0) fs of M-shell vacancies of krypton in such a pump-probe experiment.

Steering attosecond electron wave packets with light

Photoelectrons excited by extreme ultraviolet or x-ray photons in the presence of a strong laser field generally suffer a spread of their energies due to the absorption and emission of laser photons. We demonstrate that if the emitted electron wave packet is temporally confined to a small fraction of the oscillation period of the interacting light wave, its energy spectrum can be up- or downshifted by many times the laser photon energy without substantial broadening. The light wave can accelerate or decelerate the electron's drift velocity, i.e., steer the electron wave packet like a classical particle. This capability strictly relies on a sub-femtosecond duration of the ionizing x-ray pulse and on its timing to the phase of the light wave with a similar accuracy, offering a simple and potentially single-shot diagnostic tool for attosecond pump-probe spectroscopy.

[Effects of a high intensity training program on patients with chronic obstructive airways disease (COAD)]

In a controlled/prospective clinical trial we examined 125 patients with moderate COAD, 84 of which performed a high-intensity training program on cycle ergometers.

METHODS

All participants (controls n = 39, training-group n = 84, age 48.7 versus 48.1 years, FEV1 62.3 % vs. 63.1 % of predicted) were examined spiroergometrically (ramp protocol, increment 10 W/min), the anaerobic threshold (AT) determined and a training intensity calculated (AT + 40 % of the difference to peak exercise). Training was carried out on cycle ergometers with 5 training units weekly at 40 minutes each. We aimed at a minimum of 22 training units during 4 weeks.

RESULTS

Both groups improved in the lung function at rest (FEV1 + 11 % versus + 12 % in the controls). Only for the training group we found a statistically significant improvement in maximum exercise capacity (O2 uptake + 286.4 ml vs. + 72.4 ml, maximum workrate + 20.0 watts vs. + 5.7 W), of the anaerobic threshold (AT improved by 8.4 watts vs. 5.1 W) as well as in the metabolic load (lactate decreased by 1.3 mmol vs. 0.2 mmol, ventilation decreased by 3.8 l/min vs. 2.3 l/min). In most subscales of the SF-36 questionnaire quality of living improved more clearly in the training group, whereas the LAQ questionnaire showed no group-specific differences and no improvement after training.

CONCLUSION

We conclude from the result that a high intensity training program can be recommended as a useful and low-risk component in pulmonary rehabilitation programs.

Quantum transport in nonuniform magnetic fields: Aharonov-Bohm ring as a spin switch

We study spin-dependent magnetoconductance in mesoscopic rings subject to an inhomogeneous in-plane magnetic field. We show that the polarization direction of transmitted spin-polarized electrons can be controlled via an additional magnetic flux such that spin flips are induced at half a flux quantum. This quantum interference effect is independent of the strength of the nonuniform field applied. We give an analytical explanation for one-dimensional rings and numerical results for corresponding ballistic microstructures.

Attosecond metrology

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter timescales. Recent developments have pushed the duration of laser pulses close to its natural limit-the wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure, but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace electronic dynamics with a time resolution of </= 150 as by using a subfemtosecond soft-X-ray pulse and a few-cycle visible light pulse. Our measurement indicates an attosecond response of the atomic system, a soft-X-ray pulse duration of 650 +/- 150 as and an attosecond synchronism of the soft-X-ray pulse with the light field. The demonstrated experimental tools and techniques open the door to attosecond spectroscopy of bound electrons.

Multiple beam interference in a quadrupolar glass fiber

Motivated by the recent observation of periodic filter characteristics of an oval-shaped microcavity, we study the possible interference of multiple beams in the far field of a laser-illuminated quadrupolar glass fiber. From numerical ray-tracing simulations we obtain the interference-relevant length-difference spectrum and compare it with data extracted from the experimental filter results. Our analysis reveals that different polygonal cavity modes that are refractively output coupled in the high-curvature region of the fiber contribute to the observed far-field interference.

X-ray pulses approaching the attosecond frontier

Single soft-x-ray pulses of approximately 90-electron volt (eV) photon energy are produced by high-order harmonic generation with 7-femtosecond (fs), 770-nanometer (1.6 eV) laser pulses and are characterized by photoionizing krypton in the presence of the driver laser pulse. By detecting photoelectrons ejected perpendicularly to the laser polarization, broadening of the photoelectron spectrum due to absorption and emission of laser photons is suppressed, permitting the observation of a laser-induced downshift of the energy spectrum with sub-laser-cycle resolution in a cross correlation measurement. We measure isolated x-ray pulses of 1.8 (+0.7/-1.2) fs in duration, which are shorter than the oscillation cycle of the driving laser light (2.6 fs). Our techniques for generation and measurement offer sub-femtosecond resolution over a wide range of x-ray wavelengths, paving the way to experimental attosecond science. Tracing atomic processes evolving faster than the exciting light field is within reach.

Femtosecond X-Ray fluorescence

Using few-cycle-driven coherent laser harmonics, K-shell vacancies have been created in light elements, such as boron (E(B) = 188 eV) and carbon (E(B) = 284 eV), on a time scale of a few femtoseconds for the first time. The capability of detecting x-ray fluorescence excited by few-femtosecond radiation with an accuracy of the order of 1 eV paves the way for probing the evolution of the microscopic environment of selected atoms in chemical and biochemical reactions on previously inaccessible time scales (<100 fs) by tracing the temporal evolution of the "chemical shift" of peaks associated with inner-shell electronic transitions in time-resolved x-ray fluorescence and photoelectron spectra.

Is absolute noninvasive temperature measurement by the Pr[MOE-DO3A] complex feasible

Recently, the feasibility of the praseodymium complex of 10-(2-methoxyethyl)-1,4,7,10-tetraaza-cyclododecane-1,4,7-tr iacetate (Pr[MOE-DO3A]) for non-invasive temperature measurement via 1H spectroscopy has been demonstrated. Particularly the suitability of the complex for non-invasive temperature measurements including in vivo spectroscopy without spatial resolution as well as first spectroscopic imaging measurements at low temporal resolution (> or = 4 min) and high temporal resolution (breath hold, approximately 20 s) has been shown. As of today, calibration curves according to the particular experimental conditions are necessary. This work aims to clarify whether the Pr[MOE-DO3A] probe in conjunction with 1H-NMR spectroscopy allows non-invasive absolute temperature measurements with high accuracy. The measurement results from two different representative media, distilled water and human plasma, show a slight but significant dependence of the calibration curves on the surrounding medium. Calibration curves in water and plasma were derived for the temperature dependence of the chemical shift difference (F) between Pr[MOE-DO3A]'s OCH3 and water with F = -(27.53 +/- 0.04) + (0.125 +/- 0.001) x T and F = -(27.61 +/- 0.02) + (0.129 +/- 0.001) x T, respectively, with F in ppm and T in degrees C. However, the differences are minuscule even for the highest spectral resolution of 0.001 ppm/pt, so that they are indistinguishable under practical conditions. The estimated temperature errors are +/- 0.18 degrees C for water and +/- 0.14 degrees C for plasma and with that only slightly worse than the measurement accuracy of the fiber-optical temperature probe (+/- 0.1 degrees C). It can be concluded that the results obtained indicate the feasibility of the 1H spectroscopy method in conjunction with the Pr[MOE-DO3A] probe for absolute temperature measurements, with a maximum accuracy of +/- 0.2 degrees C.

Fast spectroscopic imaging for non-invasive thermometry using the Pr[MOE-DO3A] complex

The praseodymium complex of 10-(2-methoxyethyl)-1,4,7,10-tetraaza-cyclododecane-1,4,7-tr iacetate) was evaluated as a temperature-sensitive contrast agent using the temperature dependence (approximately 0.12 ppm degrees C(-1)) of the chemical shift of its methoxy side group signal. Pr[MOE-DO3A] was employed in combination with spectroscopic imaging (SI) methods for the determination of spatially resolved 2D and 3D temperature distributions in phantoms. Conventional SI and fast echo planar SI sequences (EPSI) were implemented on a 4.7 T MR imaging system fulfilling the demands for non-invasive thermometry (NIT) with respect to thermal and temporal resolution, being <1 degree C and <20 s total measuring time, respectively. The sequences are based on a fast spin echo SI method taking into account the very short relaxation times of the Pr complex methoxy group (T1 = 28 ms, T2 = 13 ms) and its chemical shift difference (-24 ppm) from water. Calibration curves were measured in a uniformly heated water phantom and 2D SI methods were applied to dynamic heating experiments. The average differences between the temperatures measured via fibreoptic thermometer and those derived from the spectroscopic methods were < or =0.2 degrees C. Furthermore, 3D EPSI experiments with a 16 x 16 x 16 matrix size yielded temperature measurements within 17 s from voxels of size 3 x 3 x 3 mm3.

1H and 31P NMR characterisation of a double breast coil for spectroscopic measurements and imaging

For the first time a double turn breast coil has been described which can be used for 1H imaging, 1H spectroscopy and 31P spectroscopy. The paper describes basic technical features of the coil, coil design, B1 field/excitation field distribution for 1H and 31P, sensitivity, and feasibility for 31P spectroscopic in vivo studies. The main advantage of the double frequency tuneable coil is that 1H imaging for tumor localization and 31P spectroscopy for response control can be done without an additional repositioning of the patient.

Comparison of four magnetic resonance methods for mapping small temperature changes

Non-invasive detection of small temperature changes (< 1 degree C) is pivotal to the further advance of regional hyperthermia as a treatment modality for deep-seated tumours. Magnetic resonance (MR) thermography methods are considered to be a promising approach. Four methods exploiting temperature-dependent parameters were evaluated in phantom experiments. The investigated temperature indicators were spin-lattice relaxation time T1, diffusion coefficient D, shift of water proton resonance frequency (water PRF) and resonance frequency shift of the methoxy group of the praseodymium complex (Pr probe). The respective pulse sequences employed to detect temperature-dependent signal changes were the multiple readout single inversion recovery (T One by Multiple Read Out Pulses; TOMROP), the pulsed gradient spin echo (PGSE), the fast low-angle shot (FLASH) with phase difference reconstruction, and the classical chemical shift imaging (CSI). Applying these sequences, experiments were performed in two separate and consecutive steps. In the first step, calibration curves were recorded for all four methods. In the second step, applying these calibration data, maps of temperature changes were generated and verified. With the equal total acquisition time of approximately 4 min for all four methods, the uncertainties of temperature changes derived from the calibration curves were less than 1 degree C (Pr probe 0.11 degrees C, water PRF 0.22 degrees C, D 0.48 degrees C and T1 0.93 degrees C). The corresponding maps of temperature changes exhibited slightly higher errors but still in the range or less than 1 degree C (0.97 degrees C, 0.41 degrees C, 0.70 degrees C, 1.06 degrees C respectively). The calibration results indicate the Pr probe method to be most sensitive and accurate. However, this advantage could only be partially transferred to the thermographic maps because of the coarse 16 x 16 matrix of the classical CSI sequence. Therefore, at present the water PRF method appears to be most suitable for MR monitoring of small temperature changes during hyperthermia treatment.

Non-invasive MR thermometry by 2D spectroscopic imaging of the Pr[MOE-DO3A] complex

Future progress in regional hyperthermia requires a practical method for non-invasive thermometry. In magnetic resonance tomography, spin density, T1 relaxation time, diffusion coefficient and proton resonance frequency are candidates to measure temperature distributions. When used clinically in the pelvic region, all these methods are compromized by artifacts arising from different tissues, tissue alterations under hyperthermia, physiological and random movements, inhomogeneities, drift phenomena, and field instabilities. In this study a paramagnetic complex was evaluated, Pr[MOE-DO3A], with praseodymium as central atom, similar to common gadolinium containing MRI contrast media. The temperature dependence of its methoxy side group approximately -24 ppm downfield from the water resonance at 25 degrees C was employed to determine 2-D temperature distributions in a cylindrical agar phantom containing 9.5 mM of Pr[MOE-DO3A]. The phantom was heated externally through a water jacket creating a stationary temperature distribution throughout the phantom. At first, the correlation between temperature and the chemical shift of the methyl group of the lanthanide complex Pr[MOE-DO3A] was determined. Calibration curves obtained exhibited a linear relationship of 0.12 +/- 0.01 ppm/degree C, nearly independent from the surrounding medium. Local temperature distributions were determined employing the spatially resolved method of spectroscopic imaging (SI). 2-D spectroscopic images for three orthogonal slices were obtained by narrow-band excitation and 16 phase encoding steps in two dimensions. The FOV was 180 mm and the slice thickness in all cases was 20 mm for maximal spatial temperature resolution (11.2 x 11.2 mm2). The results indicate a measurement time of about 5s per acquisition under the following conditions: An estimated concentration of 1 mmol/l, a reduced matrix size of 8 x 8, and a reduced repetition time of 3 x T1 (TR approximately 85 ms). Those SI measurements produced a SNR of approximately 4 per acquisition, a measurements duration of 10-20 s, equivalent to two to four acquisitions per spectrum, seem sufficient for online temperature monitoring during hyperthermia. The in vitro data suggest the spectroscopic temperature measurement utilizing a temperature-sensitive Pr[MOE-DO3A] complex with a therapeutically realistic concentration of 1 mmol/l to be suitable for clinical use. Compared to the methods tested so far (rho, T1, diffusion, proton resonance), the method presented has the unique advantage of being less susceptible to artifacts. The competing methods of non-invasive thermometry employing magnetic resonance imaging are currently being investigated using the same experimental setup.

Involvement of the esophagus in the cramp-fasciculation syndrome

A 35-year-old male patient presented with symptoms of a cramp-fasciculation syndrome, but also reported difficulties swallowing. Esophageal manometry showed spontaneous nonperistaltic contractions, pathologically increased amplitudes and duration of the contractile complexes, and an asynchronous propagation. Electromyographic evidence of fasciculations in the sternocleidomastoid and pectoralis muscles was found. Apparently all types of peripheral motor fibers can be involved in this heterogeneous syndrome, including cranial motor nerves, the vagal nerve, and enteric motor fibers of the gastrointestinal tract.

Three-dimensional monitoring of small temperature changes for therapeutic hyperthermia using MR

Radiofrequency hyperthermia of deep-seated pelvic tumors requires noninvasive monitoring of temperature distributions in patients. Methods of MR thermography were reported to be a promising tool in solving this problem. However, to be truly useful for monitoring hyperthermia treatments, MR thermography should be able to cover the entire pelvis in acquisition times no longer than for a breath-hold (< or = 15 seconds) and to resolve small temperature differences (< 1 degrees C). Three methods exploiting the temperature dependence of spin-lattice relaxation time (T1), of self-diffusion coefficient (D), and of chemical shift of proton resonance frequency (PRF) were applied in phantom experiments; the pulse sequences were the T1-weighted gradient echo, the pulsed diffusion gradient spin echo made faster through the keyhole technique, and the gradient echo with the phase reconstruction, respectively. The high planar resolution was compromised, and instead, coarse and more isotropic voxels were used. Experiments were performed in two consecutive steps, thus imitating a possible scenario for monitoring hyperthermia. In the first step, calibration curves were recorded, which were then used in the second step to obtain maps of temperature changes. The results show a clear superiority of the PRF method, followed by the D and the T1 methods. The uncertainty of temperature changes predicted both from calibration curves and from maps was less than 1 degrees C only with the PRF and the D-based methods.

Dichotomy of blood- and skin-derived IL-4-producing allergen-specific T cells and restricted V beta repertoire in nickel-mediated contact dermatitis

In this study we compared the phenotype and cytokine patterns of nickel-specific T cell clones (TCC) derived from blood samples and positive patch test reactions. A total of 252 nickel-specific TCC were established from three nonatopic patients with allergic contact dermatitis caused by nickel. All TCC expressed the TCR-alpha beta, and 77% were CD4+ compared with 21% CD8+ TCC. In contrast to blood-derived TCC, the majority of skin-derived CD4+ or CD8+ T lymphocytes produced IL-4 either in combination with IFN-gamma (type 0 cytokine pattern) or IL-4 exclusively (type 2 pattern). Skin-derived nickel-specific TCC of each patient secreted significantly more IL-4 than blood-derived TCC of the same individual. Analysis of TCR-V beta repertoire from two patients indicated that >40% of the tested TCC expressed one of the following V beta elements: V beta 13.1/13.2, V beta 20, V beta 2, V beta 6.7, or V beta 14. Only 20% of unstimulated T cells but >40% of nickel-stimulated T cells derived from peripheral blood of the same individuals expressed these V beta elements, suggesting a selection of certain TCR-V beta elements by nickel sulfate in these patients. In contrast to the compartmentalization of IL-4 production, there were no major differences in the expression of TCR-V beta elements between blood- and skin-derived nickel-specific TCC. These results point to a modulation of the cytokine production pattern of T lymphocytes after their migration from peripheral blood into the skin and a production of the type 2 cytokine IL-4 in acute eczematous lesions in nonatopic individuals.

Dichotomy of blood- and skin-derived IL-4-producing allergen-specific T cells and restricted V beta repertoire in nickel-mediated contact dermatitis

In this study we compared the phenotype and cytokine patterns of nickel-specific T cell clones (TCC) derived from blood samples and positive patch test reactions. A total of 252 nickel-specific TCC were established from three nonatopic patients with allergic contact dermatitis caused by nickel. All TCC expressed the TCR-alpha beta, and 77% were CD4+ compared with 21% CD8+ TCC. In contrast to blood-derived TCC, the majority of skin-derived CD4+ or CD8+ T lymphocytes produced IL-4 either in combination with IFN-gamma (type 0 cytokine pattern) or IL-4 exclusively (type 2 pattern). Skin-derived nickel-specific TCC of each patient secreted significantly more IL-4 than blood-derived TCC of the same individual. Analysis of TCR-V beta repertoire from two patients indicated that &gt;40% of the tested TCC expressed one of the following V beta elements: V beta 13.1/13.2, V beta 20, V beta 2, V beta 6.7, or V beta 14. Only 20% of unstimulated T cells but &gt;40% of nickel-stimulated T cells derived from peripheral blood of the same individuals expressed these V beta elements, suggesting a selection of certain TCR-V beta elements by nickel sulfate in these patients. In contrast to the compartmentalization of IL-4 production, there were no major differences in the expression of TCR-V beta elements between blood- and skin-derived nickel-specific TCC. These results point to a modulation of the cytokine production pattern of T lymphocytes after their migration from peripheral blood into the skin and a production of the type 2 cytokine IL-4 in acute eczematous lesions in nonatopic individuals.

Body distribution of free, liposomal and nanoparticle-associated mitoxantrone in B16-melanoma-bearing mice

B16-melanoma-bearing mice were treated with four different formulations containing equivalent doses of the highly effective antineoplastic drug mitoxantrone. The formulations were: A mitoxantrone solution, a negatively charged liposome preparation (small unilamellar vesicles), a 14C-labeled polybutylcyanoacrylate- (PBCA) nanoparticle suspension, and a suspension of poloxamine 1508-coated 14C-PBCA-nanoparticles. After 1, 4 and 24 hr, three animals of each group were killed and the mitoxantrone concentrations in the blood, tumor, liver, spleen, heart and bone marrow were determined using an high performance liquid chromatography technique. Additionally, the concentrations of PBCA particles in the same tissues were measured by scintillation counting to compare the mitoxantrone distribution with the corresponding PBCA nanoparticle distribution. Each formulation led to a different body distribution profile of the drug. Liposomes drastically increased the blood level of mitoxantrone even after 24 hr, although free drug was cleared quickly. Liposomes also raised the concentration in the liver and spleen, but not the drug level in the tumor. PBCA-nanoparticles considerably increased the mitoxantrone concentrations in tumor, heart and spleen. However, the increase in tumor concentrations was not statistically significant due to the high variability. Nevertheless, the tumor growth was reduced significantly (P < .05) compared to both, the liposome and the solution preparation. The nanoparticle polymer concentrations did not completely mirror those of the drug concentrations. Especially in the heart, where no nanoparticle polymer radioactivity was found, the particle concentration did not completely correspond to the mitoxantrone concentration, revealing that a part of the drug was lost from the particles. These pharmacokinetic results correspond to parallel therapeutic effects obtained with mitoxantrone-loaded nanoparticles and liposomes in the B16 melanoma.

Heat response of HT29 cells depends strongly on perfusion--a 31P NMR spectroscopy, HPLC and cell survival analysis

A model system of perfused human colon adenocarcinoma cells (HT29) encapsulated in alginate was used to examine metabolic response to heat therapy with 31P NMR spectroscopy, HPLC and cell survival analysis. The presented data show, that perfused (medium flow during hyperthermia) and non-perfused (no medium flow during hyperthermia) cells are very difficult in their sensitivity to hyperthermia. Under equivalent experimental conditions with respect to medium pH, oxygen and nutrient concentration, encapsulated perfused HT 29 cells display a significantly lower thermal sensitivity than non-perfused cells. This reduced sensitivity of perfused cells is characterized by an increased cell survival and relative ATP concentration, and reduced drop of the NTP/Pi ratio in the long-term follow up towards zero. The relative ATP concentration determined by HPLC after hyperthermia is correlated with the clonogenic survival fraction. There is a direct relationship, depending on the specific experimental conditions (perfused, non-perfused). For perfused cells only a slight dependency of survival and relative ATP concentration on heat dose is observed. In consequence, the correlation between survival and relative ATP concentration is weak, described by log(SFperf) = 0.7*[ATP-12.4, R2 = 0.79, p < 0.04. For non-perfused cells the correlation is stronger resulting in a relationship of log(SFno perf) = 0.6*[ATP]-9.0, R2 = 0.98, p < 0.0002. Altogether, the presented data suggest that the relative ATP concentration measured by HPLC after hyperthermia might be predictive for cell survival. On the other hand, a dependence between cell survival and long-term changes of NTP/Pi has been found. The results confirm the importance of tumour perfusion for hyperthermia-induced metabolic changes and cytotoxicity and therefore, for the therapeutic outcome.

[An interstitial miniature antenna for localized in vivo P-31 MR spectroscopy]

BACKGROUND

Phosphorus spectroscopy can be used to assess response in tumor therapy and to monitor response. An additional response parameter would be useful for individualization in oncological therapy. Methodical problems of localisation and contamination make it more difficult to interpret and reproduce the spectra. Interstitial and endoluminal spectroscopy antennas placed directly within or close to the tumor could provide help in this problem.

MATERIAL AND METHOD

We developed an interstitial 31P MRS antenna together with a tuning network which can be used in thermometry catheters for hyperthermia within an internal lumen of 1.1 mm in diameter. A prototype of this type of miniature antenna suitable for use in Siemens MRI scanners at 1.5 T was described spectroscopically with regard to excitation profile, range and SNR.

RESULTS

In terms of quality, the excitation profiles of the interstitial antennas in relation to orientation correspond to those of comparable but considerably larger endocavitary antennas and catheter coils for MR imaging and spectroscopy. Maximum sensitivity was achieved by aligning the coil normal perpendicular to the B0 field. Signal losses of up to 50% have to be reckoned with when using other orientations. The maximum range of the interstitial antenna was determined using spectroscopy and was found to be 5 mm, i.e. 9 times coil radius. The sensitivity (SNR, detection sensitivity) of the studied type of interstitial antenna allows in vivo 31P spectroscopy to be performed despite the unusually low axial dimension (coil radius r = 0.55 mm). The prototype of the described interstitial antenna was used to measure an in vivo spectrum from the back muscle of a rabbit in 10 min. Nevertheless, the detection volume of at least some ml necessary for 31P spectroscopy results mainly from the large antenna length.

CONCLUSION

The sensitivity (SNR, detection sensitivity) of the interstitial antenna needs to be further improved in order to assess treatment response in patients. However, the construction principle is suitable for intracavitary 31P spectroscopy antenna with larger diameters, which can be used for advanced rectal, cervical and prostate carcinomas.

Influence of the major histocompatibility complex on age at onset of chronic lymphoid leukaemia

The major histocompatibility complex is one of the interactive factors in the multifactorial model of carcinogenesis. Its main influence in experimental models is on the age at onset of malignancies. We have previously shown a similar effect of homozygosity for HLA-DR53 in CML. In the present study, we investigated 79 patients with CLL and 329 local controls from Germany. In addition to full serotyping, all patients and 116 of controls were also typed by HLA-DRB PCR analysis. The homozygosity rates for DR53 in patients under and over the median age (60 years) were 18.6% and 2.9%, respectively (p = 0.03). Eight of the 9 homozygous patients were under the median age. The sex ratio in the DR53 homozygous group was reversed in favour of females. The homozygosity rates for DR53 were different in the overall groups of patients and controls, yielding a relative risk (RR) of 2.4 (p = 0.03). This association was stronger in the early-onset group compared to age-matched controls (RR = 4.4; p = 0.008) and for females with an early onset compared to age- and sex-matched controls (RR = 17.9; p = 0.0008). The simultaneous occurrence of the alleles of the haplotype A2B62DR4 showed a strong association with CLL (RR = 4.1; p = 0.002). This was probably the reason behind the association with HLA-DRB1*0401 (RR = 2.4; p = 0.009). Compared to the accelerating effect of HLA-DR53, HLA-DR52 showed a significant delaying effect on the onset of CLL. These findings confirmed the influence of the HLA complex on the development of another leukaemia.

Endothelin (ET-1) is involved in the contrast media induced nephrotoxicity in children with congenital heart disease

In 77 children with congenital heart disease urinary endothelin-1 (ET-1), an indicator of intrarenal endothelin release, was compared to urinary excretion of total protein, albumin, immunoglobuline G (IgG), alpha 1-microglobuline (alpha 1-MG), N-acetyl-beta-D-glucosaminidase (NAG) and villin. Urine samples were collected the day before and immediately after cardiac angiography with high (Conray 70; n = 56; CON) or low osmolality contrast media (Solutrast 300; n = 21; SOL) to assess the relationship between urinary endothelin and glomerular and tubular nephrotoxicity of contrast media. The children were further subdivided according to age: less than 1 year-CON 1 (n = 20); SOL 1 (n = 12) and 1-18 years CON 2 (n = 36); SOL 2 (n = 9). Results (median): 1. There are no significant changes in total protein-, albumin- and IgG-excretion as parameters of glomerular toxicity. 2. Tubular toxicity of contrast media is shown by significant increase of alpha 1-MG-(10.0 to 23.2 mg/g Crea; p < 0.001), NAG-(5.9 to 9.6 mg/g Crea; p < 0.001) and Villin-excretion (1.0 to 2.0 STS, p < 0.001) in all children. 3. Endothelin excretion (101.0 to 163.0 ng/g Crea, p < 0.001) and concentration (42.5 to 56.0 pg/ml; p < 0.001) were elevated after angiography in all children. 4. The changes in endothelin excretion are correlated to the changes in alpha 1-MG (r = 0.65; p < 0.001) and NAG (r = 0.43, p < 0.001) in all children.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of four drug-resistant P388 sublines: resistance/sensitivity in vivo, resistance-and proliferation-markers, immunogenicity

It was the aim of this study to compare drug-resistant sublines of the murine P388 in relation to resistance markers, the resistant phenotype and immunogenicity. Resistance to drugs either belonging to the MDR type (Doxorubicin, Vincristine, Mitoxantrone) or to the non-MDR type (Methotrexate) was generated in vivo in order to mimic the clinical situation. All resistant sublines expressed the mdr1 gene and the p-glycoprotein determined on m-RNA level or immunohistochemically, while no expression was registered in the parent P388. The rhodamine 123 fluorescence as marker for the energy dependent drug efflux pump was decreased only in the MDR-sublines, while the parent P388 and the Methotrexate-resistant line retained 100% or 90% of the dye, respectively. This indicates that the rhodamine efflux is a more function-related marker for MDR than the mdr1 gene and the pgp. The in vivo characterization of the sublines as regards their sensitivity to cytostatics revealed a clear-cut cross-resistance to MDR drugs in the MDR-lines, while the Methotrexate resistant subline was only cross-resistant to Cytarabine. In each resistant subline collateral sensitivity to certain but different cytostatics was observed. Experiments to overcome resistance by concomitant treatment with the modulators Nifedipine, Verapamil, Cyclosporin A and Chloroquin led to only limited success. The sublines P388/Mitox, P388/Vinc and P388/MTX developed immunogenicity which was never registered in the original P388. Vaccination with lethally irradiated drug-resistant cells resulted in a substantial rejection of viable tumor cells of the same line. With the P388/Mitox and P388/Vinc also an over-cross immunization was possible. This generation of immunogenicity as a concomitant characteristic of resistance should be considered as therapeutic potential also in the treatment of clinical cancer.

Endothelin excretion during ketoacidosis does not correlate with tubular dysfunction

Urinary excretion of endothelin was measured by radioimmunoassay in children with diabetes mellitus during severe ketoacidosis and 12 days later when blood pH and blood glucose concentrations were normal. Metabolically stable diabetic children served as controls. Results from apparently healthy children without diabetes mellitus were used as normal values. Renal tubular injury was evaluated by the urinary excretion of the proximal tubular marker alpha 1-microglobulin and the distal tubular marker Tamm-Horsfall protein (THP). During ketoacidosis we detected a decreased glomerular filtration rate associated with highly significant changes in the excretion of alpha 1-microglobulin, indicating proximal tubular damage, and THP, suggesting disturbance of cells of the ascending loop of Henle. The daily excretion of endothelin was unaltered but the ratio of endothelin/creatinine or endothelin excretion/creatinine clearance were significantly enhanced. In conclusion, we could demonstrate that, despite a proximal and distal tubular cell dysfunction, endothelin excretion is not elevated during ketoacidosis. The increased endothelin excretion when related to creatinine clearance may be a consequence of disturbed proximal tubular function or dysfunction of the renal medulla.

Renal excretion of endothelin in children is influenced by age and diuresis

Endothelin is a peptide with vasoactive and diuretic potential. Its release has been demonstrated from endothelial and renal epithelial cells. Urinary excretion of endothelin, as shown by others, is thought to reflect intrarenal production. We measured endothelin by RIA in a population of healthy children from Germany and Hungary (group 1), neonates (group 3) and children before and during forced diuresis (groups 2a and 2b). Group 1 consisted of 24 children living in Germany and 13 children resident in Hungary. The age range in this group was 2.9-17 years. Daily excretion correlated significantly with age (r = 0.48, p < 0.001), but endothelin excretion corrected for body surface area remained constant with regard to the age group studied. This indicates that body or kidney size may influence endothelin excretion, respectively. There was no difference in endothelin excretion between the two countries. In premature infants and neonates (group 3), daily excretion of endothelin was highest in infants with very low gestational ages and decreased in full-term neonates to values not significantly different to the group of older children. The high values in premature infants may have been influenced by mechanical ventilation of physical stress, which cannot be differentiated in this study, however. In contrast to reported results in adults, renal excretion of endothelin was correlated positively to urine flow in all groups. Furthermore, the influence of forced diuresis was evaluated in 10 children with oncological disease before (group 2a) and during (group 2b) forced diuresis with fluid load (3 l/m2; n = 4) and fluid load with furosemide injection (0.3-1.0 mg/kg body weight; n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)

[HLA and selective IgA deficiency]

A selective deficiency of IgA is developed significantly (p < 0.05) more frequently by HLA-A2-negative than by HLA-A2-positive healthy persons. The frequent combination of A1/A3 is absent. The incidence of HLA-B8-positive persons is increased (p < 0.01). A selective disadvantage is discussed.