Macroscopic temporally and spectrally resolved fluorescence imaging enhanced by laser-wavelength multiplexing

We present a laser scanning system for macroscopic samples that records fully resolved decay curves in individual pixels, resolves the images in 16 wavelength channels, and records simultaneously at several laser wavelengths. By using confocal detection, the system delivers images that are virtually free of lateral scattering and out-of-focus haze. Image formats can be up to 256 × 256 pixels and up to 1024 time channels. We demonstrate the performance of the system both on model experiments with fluorescent micro-beads and on the tumor model in the living mice.

Patterns of small involuntary fixation saccades (SIFSs) in different neurodegenerative diseases: the role of noise

During the attempt to steadily fixate at a single spot, sequences of small involuntary fixation saccades (SIFSs, known also as microsaccades οr intrusions) occur which form spatio-temporal patterns such as square wave jerks (SWJs), a pattern characterised by alternating centrifugal and centripetal movements of similar magnitude. In many neurodegenerative disorders, SIFSs exhibit elevated amplitudes and frequencies. Elevated SIFS amplitudes have been shown to favour the occurrence of SWJs ("SWJ coupling"). We analysed SIFSs in different subject groups comprising both healthy controls (CTR) and patients with amyotrophic lateral sclerosis (ALS) and progressive supranuclear palsy (PSP), i.e. two neurodegenerative diseases with completely different neuropathological basis and different clinical phenotypes. We show that, across these groups, the relations between SIFS amplitude and the relative frequency of SWJ-like patterns and other SIFS characteristics follow a common law. As an explanation, we propose that physiological and technical noise comprises a small, amplitude-independent component that has little effect on large SIFSs, but causes considerable deviations from the intended amplitude and direction of small ones. Therefore, in contrast to large SIFSs, successive small SIFSs have a lower chance to meet the SWJ similarity criteria. In principle, every measurement of SIFSs is affected by an amplitude-independent noise background. Therefore, the dependence of SWJ coupling on SIFS amplitude will probably be encountered in almost any group of subjects. In addition, we find a positive correlation between SIFS amplitude and frequency in ALS, but none in PSP, suggesting that the elevated amplitudes might arise at different sites in the two disorders.

Dataset for multidimensional assessment to incentivise decentralised energy investments in Sub-Saharan Africa

In this data article, we present datasets from the construction of a composite indicator, the Photovoltaic Decentralised Energy Investment (PV-DEI) index, presented in detail in [1]. This article consists of a comprehensive energy-related data collected in practice from several sources, and from the outputs of the methodology described in [1]. The PV-DEI was designed and developed to measure the multidimensional factors that currently direct decentralised renewable energy investments. The PV-DEI index includes 52 indicators and was constructed because factors stimulating investment cannot be captured by a single indicator, e.g. competitiveness, affordability, or governance [1]. The PV-DEI index was built in alignment with a theoretical framework guided by an extensive review of the literature surrounding investment in decentralised Photovoltaic (PV), which led to the selection of its indicators. The structure of the PV-DEI was evaluated for its soundness using correlational assessments and principal component analyses (PCA). The raw data provided in this article can enable stakeholders to focus on specific country indicators, and how scores on these indicators contributed to a countries overall rank within the PV-DEI index. The data can be used to weight indicators depending on the specifications of several different stakeholders (such as NGOs, private sector or international institutions).

Label-Free Macroscopic Fluorescence Lifetime Imaging of Brain Tumors

Advanced stage glioma is the most aggressive form of malignant brain tumors with a short survival time. Real-time pathology assisted, or image guided surgical procedures that eliminate tumors promise to improve the clinical outcome and prolong the lives of patients. Our work is focused on the development of a rapid and sensitive assay for intraoperative diagnostics of glioma and identification of optical markers essential for differentiation between tumors and healthy brain tissues. We utilized fluorescence lifetime imaging (FLIM) of endogenous fluorophores related to metabolism of the glioma from freshly excised brains tissues. Macroscopic time-resolved fluorescence images of three intracranial animal glioma models and surgical samples of patients' glioblastoma together with the white matter have been collected. Several established and new algorithms were applied to identify the imaging markers of the tumors. We found that fluorescence lifetime parameters characteristic of the glioma provided background for differentiation between the tumors and intact brain tissues. All three rat tumor models demonstrated substantial differences between the malignant and normal tissue. Similarly, tumors from patients demonstrated statistically significant differences from the peritumoral white matter without infiltration. While the data and the analysis presented in this paper are preliminary and further investigation with a larger number of samples is required, the proposed approach based on the macroscopic FLIM has a high potential for diagnostics of glioma and evaluation of the surgical margins of gliomas.

Singlet oxygen phosphorescence imaging by superconducting single-photon detector and time-correlated single-photon counting: publisher's note

This publisher's note contains corrections to Opt. Lett.46, 1217 (2021) OPLEDP0146-959210.1364/OL.415229.

Singlet oxygen phosphorescence imaging by superconducting single-photon detector and time-correlated single-photon counting

This Letter presents, to the best of our knowledge, a novel optical configuration for direct time-resolved measurements of luminescence from singlet oxygen, both in solutions and from cultured cells on photodynamic therapy. The system is based on the superconducting single-photon detector, coupled to the confocal scanner that is modified for the near-infrared measurements. The recording of a phosphorescence signal from singlet oxygen at 1270 nm has been done using time-correlated single-photon counting. The performance of the system is verified by measuring phosphorescence from singlet oxygen generated by the photosensitizers commonly used in photodynamic therapy: methylene blue and chlorin e6. The described system can be easily upgraded to the configuration when both phosphorescence from singlet oxygen and fluorescence from the cells can be detected in the imaging mode. Thus, co-localization of the signal from singlet oxygen with the areas inside the cells can be done.

Efficacy of Retreatment After Failed Direct-acting Antiviral Therapy in Patients With HCV Genotype 1-3 Infections

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.^1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.^4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.⁸ However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

Metabolic Imaging by Simultaneous FLIM of NAD(P)H and FAD

We describe a metabolic imaging system based on simultaneous recording of lifetime images of NAD(P)H and FAD. The system uses one-photon excitation by ps diode lasers, scanning by galvanometer mirrors, confocal detection, and two parallel TCSPC FLIM recording channels. Two lasers, with wavelengths of 375nm and 410 nm, are multiplexed to alternatingly excite NAD(P)H and FAD. One FLIM channel detects in the emission band of NAD(P)H, the other in the emission band of FAD. For both channels, the data analysis delivers images of the amplitudes of the decay components, a1 and a2. We show that these are robust parameters to characterize the metabolic state of cells. FLIM results obtained from excised human-bladder tissue were in perfect agreement with histology.

First results of computer-enhanced optical diagnosis of bladder cancer

Bladder cancer is the sixth leading cancer cause worldwide. Non-muscle invasive tumors can be diagnosed and treated endoscopically. Based on biopsies alone, pathologists cannot determine the spatial organization of specimens, their relationship with each other, or their complete removal. To extend white light cystoscopy as the gold standard for bladder cancer detection, diagnosis and removal of small or flat lesions, new image-based technologies have been investigated. These include a stereo-cystoscope for improved orientation and navigation, computation of 2D and 3D panoramic images for extended visualization and documentation, as well as label-free fiber-based fluorescence-lifetime imaging (FLIM) and Raman-spectroscopy in combination with statistical data analysis. Combining all these technologies, cystoscopy can will be further enhanced to include new diagnostic possibilities.

Lightsheet fluorescence lifetime imaging microscopy with wide-field time-correlated single photon counting

We report on wide-field time-correlated single photon counting (TCSPC)-based fluorescence lifetime imaging microscopy (FLIM) with lightsheet illumination. A pulsed diode laser is used for excitation, and a crossed delay line anode image intensifier, effectively a single-photon sensitive camera, is used to record the position and arrival time of the photons with picosecond time resolution, combining low illumination intensity of microwatts with wide-field data collection. We pair this detector with the lightsheet illumination technique, and apply it to 3D FLIM imaging of dye gradients in human cancer cell spheroids, and C. elegans.

Increased Insulin Concentrations During Growth Hormone Treatment in Girls With Turner Syndrome Are Ameliorated by Hormone Replacement Therapy

OBJECTIVE

Turner syndrome (TS) is characterized by complete or partial loss of one sex chromosome and is commonly associated with short stature, metabolic changes (such as central obesity, abnormal glucose tolerance and high triglycerides) and premature ovarian insufficiency (POI). Primary management of TS during childhood and adolescence comprises treatment with human growth hormone (hGH) and, in cases with early loss of ovarian function, hormone replacement therapy (HRT). Given that metabolic parameters are altered when HRT is applied during menopause, we analyzed whether metabolic changes might be positively or negatively affected within 10 years after HRT and/or hGH in girls with TS.

DESIGN

Observational study.

METHODS

Data were collected from the medical records of 31 girls with TS attending two endocrinologic centers in Germany between 2000 and 2020. Descriptive statistics are reported as the mean ± SEM or percentages.

RESULTS

The mean age at first presentation was 99.06 ± 8.07 months, the mean height was 115.8 ± 3.94 cm, and the mean BMI 19.0 ± 0.99 was kg/m². Treatment with hGH was given to 96.8% of the girls, starting at an average age of 99.06 ± 8.70 months, and was continued for 67.53 ± 6.28 months. HRT was administered to 80.6% of all patients and was started at a mean age of 164.4 ± 4.54 months. During the follow-up, we did not observe any significant absolute changes in lipid parameters, but we detected beneficial effects of childhood hGH: significantly lower cholesterol (-0.206/month; p = 0.006), lower low density lipoprotein cholesterol (-0.216/month; p = 0.004), and higher high density lipoprotein cholesterol (+0.095/month; p = 0.048). Insulin concentrations, showed a significant increase attributable to hGH treatment (+0.206/month; p = 0.003), which was ameliorated by concomitant or subsequent HRT (-0.143/month; p = 0.039).

CONCLUSION

Treatment with hGH and HRT is provided to most girls with TS. Metabolic effects are associated with both modalities. Monitoring of metabolic changes appears to be important to detect unfavorable effects, and could guide treatment adjustment and duration.

Wide-field time-correlated single photon counting-based fluorescence lifetime imaging microscopy

Wide-field time-correlated single photon counting detection techniques, where the position and the arrival time of the photons are recorded simultaneously using a camera, have made some advances recently. The technology and instrumentation used for this approach is employed in areas such as nuclear science, mass spectroscopy and positron emission tomography, but here, we discuss some of the wide-field TCSPC methods, for applications in fluorescence microscopy. We describe work by us and others as presented in the Ulitima fast imaging and tracking conference at the Argonne National Laboratory in September 2018, from phosphorescence lifetime imaging (PLIM) microscopy on the microsecond time scale to fluorescence lifetime imaging (FLIM) on the nanosecond time scale, and highlight some applications of these techniques.

Saccadic intrusions in amyotrophic lateral sclerosis (ALS)

The attempt to quietly fixate at a small visual object is continuously interrupted by a variety of fixational eye movements comprising, among others, a continuum of saccadic intrusions (SI) which range in size from microsaccades with amplitudes ≤0.25° to larger refixation saccades of up to about 2°. The size and frequency of SI varies considerably among individuals and is known to increase in neurodegenerative diseases such as progressive supranuclear palsy (PSP), and amyotrophic lateral sclerosis (ALS). However, studies of ALS disagree whether also the frequency of SI increases. We undertook an analysis of SI in 119 ALS patients and 47 age-matched healthy controls whose eye movements during fixation and tests of executive functions (e.g antisaccades) had been recorded by video-oculography according to standardised procedures. SI were categorised according to their spatio-temporal patterns as stair case, back-and-forth and square wave jerks (a subcategory of back-and-forth). The SI of patients and controls were qualitatively similar (same direction preferences, similar differences between patterns), but were enlarged in ALS. Notably however, no increase of SI frequency could be demonstrated. Yet, there were clear correlations with parameters such as eye blink rate or errors in a delayed saccade task that suggest an impairment of inhibitory mechanisms, in keeping with the notion of a frontal dysfunction in ALS. However, it remains unclear how the impairment of inhibitory mechanisms in ALS could selectively increase the amplitude of intrusions without changing their frequency of occurrence.

Multiparametric Time-Correlated Single Photon Counting Luminescence Microscopy

Classic time-correlated single photon counting (TCSPC) technique involves detection of single photons of a periodic optical signal, registration of the photon arrival time in respect to the reference pulse, and construction of photon distribution with regard to the detection times. This technique achieves extremely high time resolution and near-ideal detection efficiency. Modern TCSPC is multi-dimensional, i.e., in addition to the photon arrival time relative to the excitation pulse, spatial coordinates within the image area, wavelength, time from the start of the experiment, and many other parameters are determined for each photon. Hence, the multi-dimensional TCSPC allows generation of photon distributions over these parameters. This review describes both classic and multi-dimensional types of TCSPC microscopy and their application for fluorescence lifetime imaging in different areas of biological studies.

Targeting head movements in humans: Compensation for disturbance from simultaneous body rotations

Vestibular information plays an important role in spatially oriented motor control and perception. With regard to reorienting head movements, little is known of (1) how vestibular mechanisms compensate for disturbances from concurrent passive trunk rotations (e.g. in a veering vehicle), and (2) whether and how this disturbance compensation is related to the perception of body orientation in space. We here address these two questions in a single experiment. Six healthy subjects (Ss) seated on a turning chair in darkness performed two tasks. (1) Head pointing: Ss made swift head movements in darkness towards the angular position in space of a previously shown visual target. These movements were disturbed by concurrent rotations of the chair, and hence the trunk, which were driven by scaled down versions of the Ss' own head-on-trunk rotations. Although unaware of the disturbance, Ss adjusted their head movements so as to attenuate its effect on head-in-space (HS) position by about 45%. (2) Visual straight ahead (VSA): Using a light pointer, Ss indicated their VSA before each head-pointing trial and tried to reproduce it after the trial. In all Ss, VSA accounted for the disturbing trunk rotation, although to individually varying degrees. No correlation could be detected between VSA reproduction and motor performance, neither within nor across subjects. A vestibular loss subject who performed the same two tasks made no compensatory movements during head pointing and did not account for the disturbance of his HS position during VSA reproduction. Three concepts of vestibular information processing for head movement control were explored with regard to their compatibility with the head-pointing results: (1) Conventional negative feedback, (2) Interaction with an efference copy, and (3) Interaction with neck proprioceptive information. Theoretical analyses and model simulations indicated that all three concepts can explain the observed disturbance compensation. However, they differ in terms of control stability in the presence of feedback time delays, with (3) being best and (1) worst. The different concepts might correspond to fast simple and slower complex compensation mechanisms, respectively, and possibly complement each other during natural behaviours. VSA reproduction may be based on analogous processing principles, but appears to involve different neural circuitries.

Fluorescence time-resolved macroimaging

While laser scanning fluorescence lifetime imaging (FLIM) is a powerful approach for cell biology, its small field of view (typically less than 1 mm) makes it impractical for the imaging of large biological samples that is often required for biomedical applications. Here we present a system that allows performing FLIM on macroscopic samples as large as 18 mm with a lateral resolution of 15 μm. The performance of the system is verified with FLIM of endogenous metabolic cofactor reduced nicotinamide adenine dinucleotide (phosphate), NAD(P)H, and genetically encoded fluorescent protein mKate2 in a mouse tumor in vivo.

Helicity asymmetry in strong-field ionization of atoms by a bicircular laser field

Ionization of atoms by an intense bicircular laser field is considered, which consists of two coplanar corotating or counterrotating circularly polarized field components with frequencies that are integer multiples of a fundamental frequency. Emphasis is on the effect of a reversal of the helicities of the two field components on the photoelectron spectra. The velocity maps of the liberated electrons are calculated using the direct strong-field approximation (SFA) and its improved version (ISFA), which takes into account rescattering off the parent ion. Under the SFA all symmetries of the driving field are preserved in the velocity map while the ISFA violates certain reflection symmetries. This allows one to assess the significance of rescattering in actual data obtained from an experiment or a numerical simulation.

99mTc-Labelled Polyclonal Human Immunoglobulin for Localization of Inflammatory Sites - Early in vitro-Results

99mTc-labelled polyclonal human immunoglobulin (HIG) has been shown to be able to localize inflammatory sites. Hypothetically these immunoglobulins bind directly to bacteria, HIG binds directly to Fc-receptors on the surface membrane of leucocytes or HIG simply passes vessels of increased permeability. To collect further information experiments were carried out in vitro with the blood of human volunteers. 0.5 mg 99mTc-HIG, 2 mg 99mTc-human albumin and 0.5 mg 99mTc-labelled murine monoclonal antigranulocyte antibodies were added to in vitro isolated human “mixed” leucocyte pellets and to 30 ml whole blood of 6 healthy volunteers. The whole blood and the directly labelled leucocyte pellet were layered and separated on a discontinuous Percoll®/ plasma gradient. The activity distribution was measured within the gradient. The 99mTc-HIG labelled gradients showed a significant uptake of the activity within the monocyte band whereas the 99mTc-albumin gradients showed no specific albumin uptake in any cellular band. The 99mTc-antibody labelled gradients showed a significantly increased uptake on granulocytes . It is concluded that in man a specific monocyte-associated uptake and binding mechanism of 99mTc-HIG plays an important role in the localisation of inflamed sites.

Hysterosalpingoscintigraphy: A Simple and Accurate Method of Evaluating Fallopian Tube Patency

A prospective study was designed to evaluate the efficacy of radionuclide hysterosalpingoscintigraphy using 99mTc-labelled human serum albumin macroaggregates in 17 patients (34 tubes). In normal females the niacroaggregates migrate spontaneously through the female reproductive tract following application into the posterior vaginal fornix. They can be seen in the uterine fornix 20 min p. i. (range: 5-90 min) and as free pelvic activity 120 min p. i. (range 40-180 min). Free pelvic activity could also be demonstrated by culdocentesis. In infertile patients with failure of tubal patency images after 180 min offered no additional information. For the routine diagnosis camera images 5, 60 and 180 min p. i. are recommended. Using 5-10 MBq 99mTc the radiation exposure to the ovaries is about 1/9th of the exposure from a normal radiologic hysterosalpingogram. The reported data show results comparable with those of hysterosalpingography (HSG) in females with patent or with nonpermeable tubes, but in cases of high-pressure patency by HSG the results of scintigraphy are superior to those of HSG. Moreover, this method provides new insights into sperm motility under various physiological and pathological conditions.

Kinetics of 99mTc-Labelled Antibodies against CD4 (T-Helper) Lymphocytes in Man

Die Verfügbarkeit 99mTc-markierter CD4-Antikörper erlaubt das Studium ihres kinetischen Verhaltens bei rheumatischen Patienten. Prospektiv wurden Patienten mit rheumatoider Arthritis untersucht. Drei dieser Patienten erhielten 250 µg eines mit 555 MBq 99mTc markierten CD4-Antikörpers (MAX16H5) injiziert. Ein Patient erhielt in vitro mit 99mTc markierte Lymphozyten. 4% der Aktivität wurden renal eliminiert. Von 4 nach 24 h p. i. fiel der Milzuptake von 7,5 auf 4%, der Leberuptake stieg von 25 auf 30%, der Knochemarkuptake blieb vergleichbar (50%), während der Uptake über einem großen erkrankten Gelenk von 2 geringfügig auf 2,5% stieg. 15 bis 30 min nach der Antikörperinjektion war eine Umverteilung von Aktivität zu registrieren, die einer Lymphozytenredistribution vergleichbar war. Die Recoveryrate (0-1 h) der in vivo markierten Zellen betrug 30%, die der in vitro markierten Zellen 19%. Ein Patient wurde mit in vitro CD4-Antikörper-markierten Lymphozyten untersucht. Ein signifikanter Unterschied der Kinetik beider Präparationen war nicht zu registrieren. Zusammenfassend schließen die Autoren, daß zirkulierende CD4-exprimierende Lymphozyten mit CD4-Antikörpern markiert werden können. Die kinetischen Daten erinnern an jene rezirkulierender Lymphozyten.

Diagxxnostic Accuracy of 99mTc-Anti-CEA Immuno- scintigraphy in Patients with Liver Metastases from Colorectal Carcinoma

17 Patienten mit 43 Lebermetastasen kolorektaler Karzinome wurden der Immunszintigraphie (IS) mit 99mTc-markierten monoklonalen Anti-CEA-Antikörpern (BW 431/26) unterzogen. Im Hinblick auf die Gesamtzahl der Raumforderungen wurden Sensitivität und diagnostische Treffsicherheit mit 21% bestimmt, bezogen auf die Patientenzahl betrugen sie 47% (mindestens eine positive Darstellung bei multiplen Metastasen) bzw. 77% bei nur einer Solitärmetastase. Die Sensitivität wurde durch Verwendung der SPECT- Technik nicht wesentlich verbessert. Eine Korrelation mit den Serum-CEA- Spiegeln ließ sich nicht nachweisen. Am besten schienen sich Lebermetastasen mittlerer Größe mit mäßiger Tumornekrose darzustellen. Die Ursache für die geringe Sensitivität ist vor allem in der ausgeprägten unspezifischen Anreicherung 99mTc-markierter Antikörper im RES der Leber zu sehen. Im Augenblick scheint die Immunszintigraphie lediglich eine ergänzende Methode zu konventionellen diagnostischen Maßnahmen darzustellen.

Ist ein TSH-Screening zur Diagnose oder zum Ausschluß der funktionellen Autonomie der Schilddrüse sinnvoll?

Ein im Normbereich gelegener TSH-Basalspiegel erlaubt heute im Screening den Ausschluß einer Schilddrüsenfunktionsstörung. Die vorliegende Studie überprüfte die Wertigkeit der TSH-Bestimmung zum Hinweis auf eine Schilddrüsenautonomie und damit die Indikation zur weiterführenden Schilddrüsendiagnostik. Hierzu wurden in einer retrospektiven Analyse 310 Patienten, die eine klinische Euthyreose bei normalen peripheren Schilddrüsenhormonparametern boten, ausgewertet. Der positive prädiktive Wert zur Diagnose einer Schilddrüsenautonomie errechnete sich mit 55,5%, der negative prädiktive Wert zum Ausschluß einer Schilddrüsenautonomie mit 87%. Somit erlaubt der TSH-Basisspiegel die Diagnose einer Schilddrüsenautonomie nicht. Der Ausschluß der Schilddrüsenautonomie kann jedoch mit einer Wahrscheinlichkeit von 87,7% geführt werden, wenn der TSH-Spiegel über 0,5 mU/l liegt. Ein TSH-Spiegel unter 0,3 mU/l läßt mit einer Wahrscheinlichkeit von 72,5% auf das Vorliegen einer Autonomie schließen.

Supprimierbarkeit autonomen Schilddrüsengewebes unter endogener und zusätzlicher exogener TSH-Suppression bei Patienten mit Schilddrüsenautonomie

Ziel: Diese retrospektive Studie überprüft bei Patienten mit funktionell relevanter Schilddrüsenautonomie den Effekt einer zusätzlich exogenen Schilddrüsenhormonsuppression auf den 99mTechnetium-Thyreoidea-Uptake (TcTU) bei bestehender endogener Suppression. Methode: Bei 21 Patienten, untersucht in den Jahren 1992-1996, wurde nach vorab endogener Suppression (end) des TSH-b und Bestimmung des TcTU nach einer zusätzlichen exogenen Suppression (ex) mit über zunächst 2 Wochen 75 μ/dl und weitere 2 Wochen 150 μg/d oder dem Körpergewicht entsprechend 2 μg/kg Levothyroxin, eine weitere TcTU-Bestimmung durchgeführt. Die gesamte Patientengruppe wird als Gruppe I mit einem TcTUend von 1,6%-7,4% unter endogener Suppression bezeichnet. Die Untergruppen wurden nach verschiedenen TcTU-Schwellen erstellt. Gruppe la TcTUend≥1,6% und <2,5%, Gruppelb TcTUend ≥2,5%, Gruppe Ic TcTUend ≥3%. Ergebnisse: Der intraindividuelle Vergleich zeigt eine signifikante Verminderung des TcTU nach zusätzlich exogener Suppression mit Levothyroxin. Im einzelnen zeigen sich folgende TcTU Werte: Die Gruppe I zeigt alle Patienten mit einem TcTUend = 3,47 ± 1,65 und einem TcTUex = 2,91 ± 1,38, entsprechend einer Reduktion von 20 rel.% (p ≤0,001); Gruppe la TcTUend = 2,5% ± 0,27, TcTUex = 1.85% ± 0,22, entsprechend 10 rel.% (p ≤0,01); Gruppe Ib TcTUend = 4,18% ± 1,59, TcTUex = 3,45% ± 1,34, entsprechend 20 rel.% (p ≤0,001); Gruppe lc TcTUend = 5,00% ± 1,43, TcTUex = 4,05% ± 1,32, entsprechend 20 rel.% (p≤0,001). Schlußfolgerung: Ausgehend von einer möglichen’ strukturellen Variabilität des autonomen SD-Gewebes mit heterogenen TSH-Rezeptoren zeigt unsere Studie eine signifikante zusätzliche exogene Supprimierbarkeit von bereits endogen supprimierten TSH-Rezeptoren.

Somatostatin Receptor Expression in the Thyroid Demonstrated with 111In-Octreotide Scintigraphy

Neuroendocrine tumors with somatostatin receptor expression may be localized by 111ln-octreotide scintigraphy. This study examines those thyroid conditions where 111 ln-octreotide uptake could be observed also in the thyroid gland. 26 consecutive patients who underwent 111 ln-octreotide scintigraphy for tumor localization were additionally examined for thyroid disease by sonography and 99mTc-pertechnetate scintigraphy. 12 of these patients had no significant thyroid uptake and had an euthyroid normal-sized thyroid gland. 14 patiens with 111ln thyroid uptakes had endemic goiters, two of them with thyroid autonomy and one with Graves’ disease. Thus, 111 ln-octreotide thyroid uptake was predominantly seen in patients with endemic goiter with or without thyroid autonomy.

Arthroscintigraphy in Suspected Rotator Cuff Rupture

Aim: In order to evaluate the diagnostic efficiency of arthroscintigraphy in suspected rotator cuff ruptures this new imaging procedure was performed 20 times in 17 patients with clinical signs of a rotator cuff lesion. The scintigraphic results were compared with sonography (n = 20), contrast arthrography (n = 20) and arthroscopy (n = 10) of the shoulder joint. Methods: After performing a standard bone scintigraphy with intravenous application of 300 MBq 99m-Tc-methylene diphosphonate (MDP) for landmarking of the shoulder region arthroscintigraphy was performed after an intraarticular injection of 99m-Tc microcolloid (ALBURES 400 μCi/5 ml). The application was performed either in direct combination with contrast arthrography (n = 10) or ultrasound conducted mixed with a local anesthetic (n = 10). Findings at arthroscopical surgery (n = 10) were used as the gold standard. Results: In case of complete rotator cuff rupture (n = 5), arthroscintigraphy and radiographic arthrography were identical in 5/5. In one patient with advanced degenerative alterations of the shoulder joint radiographic arthrography incorrectly showed a complete rupture which was not seen by arthroscintigraphy and endoscopy. In 3 patients with incomplete rupture, 2/3 results were consistant. A difference was seen in one patient with a rotator cuff, that has been already revised in the past and that suffered of capsulitis and calcification. Conclusion: Arthroscintigraphy is a sensitive technique for detection of rotator cuff ruptures. Because of the lower viscosity of the active compound, small ruptures can be easily detected, offering additional value over radiographic arthrography and ultrasound, especially for evaluation of incomplete cuff ruptures.

Clinical Implications of a New TSH-receptor-antibody-assay (DYNOtest® TRAKhuman) in Autoimmune Thyroid Diseases

Aim: Conventional radioreceptor-antibody-assays (RAAs) fail in the detection of TSH-receptor antibodies (TRAKs) in 10–30% of patients with Graves’ disease (GD). The aim of this study was the evaluation of the diagnostic and clinical impact of a new RRA (DYNOtest® TRAKhuman) which uses the human recombinant TSH-Receptor in the diagnosis of autoimmune thyroid disease. Methods: Sera from 142 consecutive patients (GD: n=50, autoimmune thyroiditis/AIT: n=92) and from 55 controls (31 patients without any thyroid disease and 14 with euthyroid goiter) were evaluated both with the DYNOtest® TRAKhuman-assay and a conventional RRA (TRAK-Assay®). Thyroid in vitro parameters and thyroid sonography were performed in all patients. Results: The DYNOtest® TRAK-assay was significantly superior to the conventional RRA in the diagnosis of GD (p < 0,00012), especially in those who were treated by thionamides (p < 0,003) and in the diagnosis of TRAK-positive patients with AIT(p < 0,003). The majority of TRAK-positive AIT-patients suffered from hypothyroidism. One false positive result in patients with euthyroid goiter was found in the TRAK-Assay® as well as in the DYNOtest® TRAKhuman-Assay. Therefore the specifity of the DYNOtest® TRAKhuman was not inferior compared with the conventional assay. Conclusion: The DYNOtest® TRAK-assay is superior in the diagnostic work up of Graves’ disease compared with a conventional TRAK-assay and offeres an equal specifity.

Immunoscintigraphy in Medullary Thyroid Cancer Using an 123I- or 111ln-Labelled Monoclonal Anti-CEA Antibody Fragment

The monoclonal anti-CEA F(ab’)2 fragment MAb BW 431/31, labelled with 123I or111 In, was used for immunoscintigraphy (IS) in 9 patients with medullary cancer of the thyroid (CCC). The results of 11 studies lead to the following conclusions: 1) When using radioiodine as a label for MAb in IS, potassium iodide is absolutely necessary to block the thyroid which is of special importance in patients with thyroid cancer; 2) Preinjection of “cold” MAb reduces the relatively high unspecific uptake (especially in bone marrow) of MAb BW 431/31, which is of special importance for the antibody labelled with 111 In; 3) IS with MAb BW 413/31 in patients with CCC and elevated serum CEA is positive only in cases with large secondaries; and 4) In patients with CCC and several manifestations of secondaries, only a single (large) metastasis may be apparent.

Radioiodination of monoclonal antibodies, proteins and peptides for diagnosis and therapy

Simple and reliable methodologies for radioiodination of proteins and peptides are described. The labeling systems are easy to assemble, capable of radioiodinating any protein or, with slight modifications, also peptide (molecular mass 1000-300,000) from kBq to GBq levels of activity for use in diagnosis and/or therapy. Furthermore, the procedures are feasible in any nuclear medicine department. Gigabecquerel amounts of activity can be handled safely. The most favored iodination methodology relies on the Iodogen system, a mild oxidating agent without reducing agents. Thus, protein degradation is minimized. Labeling yields are between 60 and 90%, and immunoreactivities remain ≥ 85%. Other radioiodination methods (chloramine-T, Bolton-Hunter) are described and briefly discussed.

F-18-FDG-hybrid-camera-PET in patients with postoperative fever

Aim: Evaluation of F-18-FDG-hybrid-camera-PET imaging in patients with undetermined postoperative fever (POF). Methods: Prospective study of 18 patients (9 women, 9 men; age 23-85 years) suffering from POF with 2-fluoro-2’-deoxyglucose (F-18-FDG) using a dual headed coincidence camera (DHCC). Surgery had been performed 5-94 days prior to our investigation. 13 of the 18 patients received antibiotic therapy during the time of evaluation. Ten (55%) had an infectious and eight (45%) a non infectious cause of fever. Results: Increased F-18-FDG-uptake outside the surgical wound occurred in 13 regions (infection n = 11, malignancy n = 2). The sensitivity of F-18-FDG-hybrid-camera-PET in imaging infection in areas outside the surgical wound was 86% and the specificity 100%, respectively. Antibiotic therapy did not negatively influence the results of F-18-FDG-scanning. Increased F-18-FDG-uptake within the surgical wound was seen in 8 of 18 patients. The sensitivity of F-18-FDG-hybrid-camera-PET in imaging infection within the surgical wound was 100% and the specificity 56%, respectively. The interval between surgery and F-18-FDG-scanning was significantly shorter in patients with false positive results compared with patients showing true negative results (median 34 vs. 54 days; p = 0,038). Conclusion: In POF-Patients, F-18-FDG transaxial tomography performed with a F-18-FDG-hybrid-camera-PET is sensitive in the diagnosis of inflammation and malignant disease within and outside the surgical wound. Because of the accumulation of the tracer both in granulation tissue and infection, the specificity in detecting the focus of fever within the surgical wound is poor.

Minimal contribution of cell-bound antibodies to the immunoscintigraphy of inflamed joints with 99mTc-anti-CD4 monoclonal antibodies

Aim: The cellular joint infiltrate in rheumatoid arthritis patients is rich in CD4-positive T-helper lymphocytes and macrophages, rendering anti-CD4 monoclonal antibodies (mAbs) suitable for specific immunoscintigraphy of human/ experimental arthritis. Following intravenous injection, however, mAbs are present both in the free form and bound to CD4-positive, circulating monocytes and T-cells. Thus, the present study aimed at analyzing the relative contribution of the free and the cell-bound component to the imaging of inflamed joints in experimental adjuvant arthritis (AA). Methods: AA rat peritoneal macrophages or lymph node T-cells were incubated in vitro with saturating amounts of 99mTc-anti-CD4 mAb (W3/25) and injected i.v. into rats with AA. Results: In vitro release of 99mTc-anti-CD4 mAb from the cells was limited (on average 1.57%/h for macrophages and 0.84%/h for T-cells). Following i.v. injection, whole body/joint scans and tissue measurements showed only negligible accumulation of radioactivity in inflamed ankle joints (tissue: 0.22 and 0.34% of the injected activity, respectively), whereas the radioactivity was concentrated in liver (tissue: 79% and 71%, respectively), kidney, and urinary bladder. Unlike macrophages, however, anti-CD4 mAb-coated T-cells significantly accumulated in lymphoid organs, the inflamed synovial membrane of the ankle joints, as well as in elbow and knee joints. Conclusion: While the overall contribution of cell-bound mAbs to the imaging of arthritic joints with anti-CD4 mAbs is minimal, differential accumulation of macrophages and T-cells in lymphoid organs and the inflamed synovial membrane indicates preferential migration patterns of these 2 cell populations in arthritic rats. Although only validated for 99mTc-anti-CD4 mAbs, extrapolation of the results to other anticellular mAbs with similar affinity for their antigen may be possible.

Patients with fever of unknown origin (FUO): diagnosis by nuclear medicine imaging

Fever of unknown origin (FUO) in immunocompetent and non neutropenic patients is defined as recurrent fever of 38,3° C or greater, lasting 2-3 weeks or longer, and undiagnosed after 1 week of appropriate evaluation. The underlying diseases of FUO are numerous and infection accounts for only 20-40% of them. The majority of FUO-patients have autoimmunity and collagen vascular disease and neoplasm, which are responsible for about 50-60% of all cases. In this respect FOU in its classical definition is clearly separated from postoperative and neutropenic fever where inflammation and infection are more common. Although methods that use in-vitro or in-vivo labeled white blood cells (WBCs) have a high diagnostic accuracy in the detection and exclusion of granulocytic pathology, they are only of limited value in FUO-patients in establishing the final diagnosis due to the low prevalence of purulent processes in this collective. WBCs are more suited in evaluation of the focus in occult sepsis. Ga-67 citrate is the only commercially available gamma emitter which images acute, chronic, granulomatous and autoimmune inflammation and also various malignant diseases. Therefore Ga-67 citrate is currently considered to be the tracer of choice in the diagnostic work-up of FUO. The number of Ga-67-scans contributing to the final diagnosis was found to be higher outside Germany than it has been reported for labeled WBCs. F-l 8-2’-deoxy-2-fluoro-D-glucose (FDG) has been used extensively for tumor imaging with PET. Inflammatory processes accumulate the tracer by similar mechanisms. First results of FDG imaging demonstrated, that FDG may be superior to other nuclear medicine imaging modalities which may be explained by the preferable tracer kinetics of the small F-l 8-FDG molecule and by a better spatial resolution of coincidence imaging in comparison to a conventional gamma camera.

Detection of Black Plastics in the Middle Infrared Spectrum (MIR) Using Photon Up-Conversion Technique for Polymer Recycling Purposes

The identification of black polymers which contain about 0.5 to 3 mass percent soot or black master batch is still an essential problem in recycling sorting processes. Near infrared spectroscopy (NIRS) of non-black polymers offers a reliable and fast identification, and is therefore suitable for industrial application. NIRS is consequently widely used in polymer sorting plants. However, this method cannot be used for black polymers because small amounts of carbon black or soot absorb all light in the NIR spectral region. Spectroscopy in the mid infrared spectral region (MIR) offers a possibility to identify black polymers. MIR spectral measurements carried out with Fourier-transform infrared spectrometers (FTIR) are not fast enough to meet economic requirements in sorting plants. By contrast, spectrometer systems based on the photon up-conversion technique are fast and sensitive enough and can be applied to sort black polymer parts. Such a system is able to measure several thousand spectra per second hence is suitable for industrial applications. The results of spectral measurements of black polymers are presented.

Interrogation of metabolic and oxygen states of tumors with fiber-based luminescence lifetime spectroscopy

The study of metabolic and oxygen states of cells in a tumor in vivo is crucial for understanding of the mechanisms responsible for tumor development and provides background for the relevant tumor's treatment. Here, we show that a specially designed implantable fiber-optic probe provides a promising tool for optical interrogation of metabolic and oxygen states of a tumor in vivo. In our experiments, the excitation light from a ps diode laser source is delivered to the sample through an exchangeable tip via a multimode fiber, and the emission light is transferred to the detector by another multimode fiber. Fluorescence lifetime of a nicotinamid adenine dinucleotide (NAD(P)H) and phosphorescence lifetime of an oxygen sensor based on an iridium (III) complex of enzothienylpyridine (BTPDM1) are explored both in model experiment in solutions and in living mice.

Detecting Prostate Cancer

BACKGROUND

When prostate cancer is suspected, the prostate gland is biopsied with the aid of transrectal ultrasound (TRUS). The sensitivity of prostatic biopsy is about 50%. The fusion of magnetic resonance imaging (MRI) data with TRUS enables the targeted biopsy of suspicious areas. We studied whether this improves the detection of prostate cancer.

METHODS

168 men with suspected prostate cancer underwent prostate MRI after a previous negative biopsy. Suspicious lesions were assessed with the classification of the Prostate Imaging Reporting and Data System and biopsied in targeted fashion with the aid of fused MRI and TRUS. At the same sitting, a systematic biopsy with at least 12 biopsy cores was performed.

RESULTS

Prostate cancer was detected in 71 patients (42.3%; 95% CI, 35.05-49.82). The detection rate of fusion-assisted targeted biopsy was 19% (95% CI, 13.83-25.65), compared to 37.5% (95% CI, 30.54-45.02) with systematic biopsy. Clinically significant cancer was more commonly revealed by targeted biopsy (84.4%; 95% CI, 68.25-93.14) than by systematic biopsy (65.1%; 95% CI, 52.75-75.67). In 7 patients with normal MRI findings, cancer was detected by systematic biopsy alone. Compared to systematic biopsy, targeted biopsy had a higher overall detection rate (16.5% vs. 6.3%), a higher rate of infiltration per core (30% vs. 10%), and a higher rate of detection of poorly differentiated carcinoma (18.5% vs. 3%). Patients with negative biopsies did not undergo any further observation.

CONCLUSION

MRI/TRUS fusion-assisted targeted biopsy improves the detection rate of prostate cancer after a previous negative biopsy. Targeted biopsy is more likely to reveal clinically significant cancer than systematic biopsy; nevertheless, systematic biopsy should still be performed, even if the MRI findings are negative.

A wide-field TCSPC FLIM system based on an MCP PMT with a delay-line anode

We report on the implementation of a wide-field time-correlated single photon counting (TCSPC) method for fluorescence lifetime imaging (FLIM). It is based on a 40 mm diameter crossed delay line anode detector, where the readout is performed by three standard TCSPC boards. Excitation is performed by a picosecond diode laser with 50 MHz repetition rate. The photon arrival timing is obtained directly from the microchannel plates, with an instrumental response of ∼190 to 230 ps full width at half maximum depending on the position on the photocathode. The position of the photon event is obtained from the pulse propagation time along the two delay lines, one in x and one in y. One end of a delay line is fed into the "start" input of the corresponding TCSPC board, and the other end is delayed by 40 ns and fed into the "stop" input. The time between start and stop is directly converted into position, with a resolution of 200-250 μm. The data acquisition software builds up the distribution of the photons over their spatial coordinates, x and y, and their times after the excitation pulses, typically into 512 × 512 pixels and 1024 time channels per pixel. We apply the system to fluorescence lifetime imaging of cells labelled with Alexa 488 phalloidin in an epi-fluorescence microscope and discuss the application of our approach to other fluorescence microscopy methods.

Correlative NAD(P)H-FLIM and oxygen sensing-PLIM for metabolic mapping

Cellular responses to oxygen tension have been studied extensively. Oxygen tension can be determined by considering the phosphorescence lifetime of a phosphorescence sensor. The simultaneous usage of FLIM of coenzymes as NAD(P)H and FAD(+) and PLIM of oxygen sensors could provide information about correlation of metabolic pathways and oxygen tension. We investigated correlative NAD(P)H-FLIM and oxygen sensing-PLIM for simultaneously analyzing cell metabolism and oxygen tension. Cell metabolism and pO2 were observed under different hypoxic conditions in squamous carcinoma cell cultures and in complex ex vivo systems. Increased hypoxia induced an increase of the phosphorescence lifetime of Ru(BPY)3 and in most cases a decrease in the lifetime of NAD(P)H which is in agreement to the expected decrease of the protein-bound NAD(P)H during hypoxia. Oxygen was modulated directly in the mitochondrial membrane. Blocking of complex III and accumulation of oxygen could be observed by both the decrease of the phosphorescence lifetime of Ru(BPY)3 and a reduction of the lifetime of NAD(P)H which was a clear indication of acute changes in the redox state of the cells. For the first time simultaneous FLIM/PLIM has been shown to be able to visualize intracellular oxygen tension together with a change from oxidative to glycolytic phenotype.

Effect of flexing and massage on in vivo human skin penetration and toxicity of zinc oxide nanoparticles

Aim: We assessed the effects of flexing and massage on human skin penetration and toxicity of topically applied coated and uncoated zinc oxide nanoparticles (˜75 nm) in vivo. Materials & methods: Noninvasive multiphoton tomography with fluorescence lifetime imaging was used to evaluate the penetration of nanoparticles through the skin barrier and cellular apoptosis in the viable epidermis. Results: All nanoparticles applied to skin with flexing and massage were retained in the stratum corneum or skin furrows. No significant penetration into the viable epidermis was seen and no cellular toxicity was detected. Conclusion: Exposure of normal in vivo human skin to these nanoparticles under common in-use conditions of flexing or massage is not associated with significant adverse events.

Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector

Time resolution is one of the main characteristics of the single photon detectors besides quantum efficiency and dark count rate. We demonstrate here an ultrafast time-correlated single photon counting (TCSPC) setup consisting of a newly developed single photon counting board SPC-150NX and a superconducting NbN single photon detector with a sensitive area of 7 × 7 μm. The combination delivers a record instrument response function with a full width at half maximum of 17.8 ps and system quantum efficiency ∼15% at wavelength of 1560 nm. A calculation of the root mean square value of the timing jitter for channels with counts more than 1% of the peak value yielded about 7.6 ps. The setup has also good timing stability of the detector-TCSPC board.

Electron rescattering in a bicircular laser field

Above-threshold ionization of rare-gas atoms by a bicircular field with its two components counterrotating is theoretically investigated by means of the improved strong-field approximation. Both direct and rescattered electrons are considered and the quantum orbits that lead into a specific final state are calculated and depicted. The angle-dependent spectrum reflects the discrete rotational symmetry of the bicircular field. The backward-scattering contributions are very similar to those generated by a linearly polarized field; several such contributions are rotated one versus the other by the symmetry angle of the discrete rotational symmetry. The forward-scattering contributions dramatically affect the velocity map at comparatively low momenta. The direct-electron spectrum observes reflection symmetry about several symmetry axes determined by the field symmetry. This is broken by rescattering.

Podokinetic circular vection: characteristics and interaction with optokinetic circular vection

Stabilising horizontal body orientation in space without sight on a rotating platform by holding to a stationary structure and circular 'treadmill' stepping in the opposite direction can elicit an illusion of self-turning in space (Bles and Kapteyn in Agressologie 18:325-328, 1977). Because this illusion is analogous to the well-known illusion of optokinetic circular vection (oCV), we call it 'podokinetic circular vection' (pCV) here. Previous studies using eccentric stepping on a path tangential to the rotation found that pCV was always contraversive relative to platform rotation. In contrast, when our subjects stepped at the centre of rotation about their vertical axis, we observed an inverted, ipsiversive pCV as a reproducible trait in many of our subjects. This ipCV occurred at the same latency as the pCV of subjects reporting the actually expected contraversive direction, but had lower gain. In contrast to pCV, the nystagmus accompanying circular treadmill stepping had the same direction in all individuals (slow phase in the direction of platform motion). The direction of an individual's pCV predicted the characteristics of the CV resulting from combined opto- and podokinetic stimulation (circular treadmill stepping while viewing a pattern rotating together with the platform): in individuals with contraversive pCV, latency shortened and both gain and felt naturalness increased in comparison with pure oCV, whereas the opposite (longer latency, reduced gain and naturalness) occurred in individuals with ipCV. Taken together, the reproducibility of ipCV, the constant direction of nystagmus and the fact that pCV direction predicts the outcome of combined stimulation suggest that ipCV is an individual trait of many subjects during compensatory stepping at the centre of rotation. A hypothetical model is presented of how ipCV possibly could arise.