Diagnosis of periprosthetic loosening of total hip and knee arthroplasty using 68Gallium-Zoledronate PET/CT.

PURPOSE: Periprosthetic loosening is a major complication after total hip and knee arthroplasty. Early and accurate diagnosis is essential to choose the right therapeutic path and to avoid further complications. The aim of the study was to evaluate the diagnostic performance of 68Gallium-Zoledronate ([68Ga]Ga-DOTAZol) PET/CT in detecting periprosthetic loosening in total hip (THA) and total knee arthroplasty (TKA). METHODS: This retrospective study included 26 patients with painful prosthesis (THA n = 17; TKA n = 16) and clinical suspicion of periprosthetic loosening, but without a confirmed diagnosis. Patients underwent [68Ga]Ga-DOTAZol PET/CT at least one year post-implantation. Diagnosis was confirmed through revision surgery or long-term clinical follow-up, with an observation period of at least 6 months. The analysis included both an assessment of the prosthesis as a unit and a separate evaluation of the individual components. Statistical analysis involved calculating sensitivity, specificity and accuracy using SPSS. RESULTS: Overall, a sensitivity of 77.8%, a specificity of 95.8% and an accuracy of 90.9% were found for detecting periprosthetic loosening, when considering the prosthesis as a unit. Individual component analyses showed a sensitivity of 71.4% and specificity of 96.2%. CONCLUSION: The use of [68Ga]Ga-DOTAZol PET/CT in periprosthetic loosening is a remarkable diagnostic tool and a promising approach. In comparison to established radionuclide tracers, 68Gallium-Zoledronate offers notable advantages due to its availability via 68Ge/68Ga-generators, improving its potential for clinical application.

[Diagnostics and Treatment of Cardiac Sarcoidosis - Consensus Paper of the German Respiratory Society (DGP) and the German Cardiac Society (DGK)]. / Diagnostik und Therapie der kardialen Sarkoidose.

Sarcoidosis is a multisystemic granulomatous disorder which affects the respiratory system in the majority of the cases. Symptomatic cardiac manifestations are found in less than 10 % of the affected cohorts and show a large heterogeneity based on the ethnic background. Cardiac sarcoidosis is not only found in patients with rhythmogenic heart disease, such as atrial and ventricular fibrillation but also in all phenotypes of cardiomyopathy. The overall morbidity and mortality caused by cardiac sarcoidosis in Germany remains unclear and large prospective international observational studies.underline the importance of this disease entity. This consensus paper on diagnostic and therapeutic algorithms for cardiac sarcoidosis is based on a current literature search and forms an expert opinion statement under the auspices of the German Respiratory Society and the German Cardiac Society. The rationale of this statement is to provide algorithms to facilitate clinical decision-making based on the individual case situation.

Energy enhancement of the target surface electron by using a 200 TW sub-picosecond laser.

One order of magnitude energy enhancement of the target surface electron beams with central energy at 11.5 MeV is achieved by using a 200 TW, 500 fs laser at an incident angle of 72° with a prepulse intensity ratio of 5×10-6. The experimental results demonstrate the scalability of the acceleration process to high electron energy with a longer (sub-picosecond) laser pulse duration and a higher laser energy (120 J). The total charge of the beam is 400±20 pC(E>2.7 MeV). Such a high orientation and mono-energetic electron jet would be a good method to solve the problem of the large beam divergence in fast ignition schemes and to increase the laser energy deposition on the target core.

[PET-CT in head and neck cancer]. / PET-CT bei Karzinomen im Kopf­Hals­Bereich.

The importance of 18F-fluorodesoxyglucose positron-emission tomography (FDG-PET) for the diagnosis of malignant disease is increasing. On one hand, this is due to the high sensitivity of this method, on the other, because the entire body can be examined. FDG-PET can be particularly advantageous for the diagnosis of head and neck tumors, where tumor staging is an important prognostic parameter and essentially determines the therapeutic regimen. This article presents the different possibilities for combined evaluation with PET and computed tomography (CT) for the diagnosis of patients with head and neck cancer. Special focus is placed on primary staging and tumor follow-up, as well as on the role of PET-CT in the diagnosis of patients with cancer of unknown primary origin (CUP). The use of PET-CT for radiotherapy planning and new aspects of PET technology are also discussed.

DEPROMP Trial: the additive value of PSMA-PET/CT-guided biopsy for prostate cancer management in biopsy naïve men-study protocol for a randomized trial.

BACKGROUND: The primary objective is to determine the proportion of men with suspected prostate cancer (PCA) in whom the management plans are changed by additive gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT) guided prostate biopsy (PET-TB) in combination with standard of care (SOC) using systematic (SB) and multiparametric magnetic resonance imaging-guided biopsy (MR-TB) compared with SOC alone. The major secondary objectives are to determine the additive value of the combined approach of SB + MR-TB + PET-TB (PET/MR-TB) for detecting clinically significant PCA (csPCA) compared to SOC; to determine sensitivity, specificity, positive and negative predictive value and diagnostic accuracy of imaging techniques, respective imaging classification systems, and each biopsy method; and to compare preoperatively defined tumor burden and biomarker expression and pathological tumor extent in prostate specimens. METHODS: The DEPROMP study is a prospective, open-label, interventional investigator-initiated trial. Risk stratification and management plans after PET/MR-TB are conducted randomized and blinded by different evaluation teams of experienced urologists based on histopathological analysis and imaging information: one including all results of the PET/MR-TB and one excluding the additional information gained by PSMA-PET/CT guided biopsy. The power calculation was centered on pilot data, and we will recruit up to 230 biopsy-naïve men who will undergo PET/MR-TB for suspected PCA. Conduct and reporting of MRI and PSMA-PET/CT will be performed in a blinded fashion. DISCUSSION: The DEPROMP Trial will be the first to evaluate the clinically relevant effects of the use of PSMA-PET/CT in patients with suspected PCA compared to current SOC. The study will provide prospective data to determine the diagnostic yields of additional PET-TB in men with suspected PCA and the impact on treatment plans in terms of intra- and intermodal changes. The results will allow a comparative analysis of risk stratification by each biopsy method, including a performance analysis of the corresponding rating systems. This will reveal potential intermethod and pre- and postoperative discordances of tumor stage and grading, providing the opportunity to critically assess the need for multiple biopsies. TRIAL REGISTRATION: German Clinical Study Register DRKS 00024134. Registered on 26 January 2021.

Radiolabelled RGD peptides for imaging and therapy.

Imaging of angiogenesis has become increasingly important with the rising use of targeted antiangiogenic therapies like bevacizumab (Avastin). Non-invasive assessment of angiogenic activity is in this respect interesting, e.g. for response assessment of such targeted antiangiogenic therapies. One promising approach of angiogenesis imaging is imaging of specific molecular markers of the angiogenic cascade like the integrin α(v)ß(3). For molecular imaging of integrin expression, the use of radiolabelled peptides is still the only approach that has been successfully translated into the clinic. In this review we will summarize the current data on imaging of α(v)ß(3) expression using radiolabelled RGD peptides with a focus on tracers already in clinical use. A perspective will be presented on the future clinical use of radiolabelled RGD peptides including an outlook on potential applications for radionuclide therapy.

Molecular imaging of avb3 expression in cancer patients.

Angiogenesis, the formation of new blood vessels, is a key process in the growth of solid tumors. Thus this process could potentially be utilized for diagnosis of malignancies by molecular imaging on the one hand and for tumor treatment on the other hand. Imaging of angiogenesis has become increasingly important with the rising use of targeted antiangiogenic therapies, like bevacizumab (Avastin). Non-invasive assessment of angiogenic activity is in this respect interesting e.g. for response assessment of such targeted antiangiogenic therapies. Several methods have been employed for imaging of angiogenesis in vivo. Mostly these approaches measure physical parameters of the tissue, e.g. blood flow, blood volume and vessel permeability. Another approach of angiogenesis imaging is imaging of specific molecular markers of the angiogenic cascade. Integrins, like avb3, but also avb5 and a5b1, play a central role in the angiogenic process and integrin avb3 binding substances can be used as imaging probes to assess integrin expression. For clinical applications, the use of radiolabeled integrin binding substances is favorable, as radiotracers can be detected with very high sensitivities in vivo. As the radiotracer approach for molecular imaging of avb3 expression is by now the only approach used in the clinical setting, it will be the focus of this review. We will summarize the current data on imaging of avb3 expression in the clinical arena using single photon emission computed tomography (SPECT) and positron emission tomography (PET). Moreover, an outlook will be presented on potential clinical applications of imaging of avb3 expression.

[PET-CT for neuroendocrine tumors and nuclear medicine therapy options]. / PET-CT bei neuroendokrinen Tumoren und nuklearmedizinische Therapiemöglichkeiten.

Neuroendocrine tumors (NET) are defined by biochemical characteristics and structures which can be specifically addressed by radioligands for diagnostic imaging as well as radionuclide therapy in nuclear medicine. Somatostatin receptor imaging has been shown to be an important part of the diagnostic process in the management of NET for a long time. In recent years a number of tracers enabling PET-based imaging of somatostatin receptors and amine precursor uptake have been developed. By combining the specific functional information of the PET signal with anatomical information by CT imaging using PET-CT hybrid scanners, primary tumors and metastases can be detected with high resolution and high sensitivity. Compared with conventional indium-111 octreotide scintigraphy PET-CT has a higher resolution and also a lower radiation exposure. In addition, quantification of the tracer uptake allows therapy monitoring. By labelling with therapeutic beta-emitters, such as lutetium-177 or yttrium-90, a systemic internal radiotherapy with somotostatin analogues (peptide radionuclide radiation therapy, PRRT) can be provided as a therapeutic option for patients with unresectable and metastasized neuroendocrine tumors.

Clinical evaluation of [68Ga]Ga-DATA-TOC in comparison to [68Ga]Ga-DOTA-TOC in patients with neuroendocrine tumours.

INTRODUCTION: [68Ga]Ga-DATA-TOC is a new radiolabelled somatostatin-analogue for positron emission tomography (PET) imaging of neuroendocrine tumours. Its advantage over DOTA-conjugated compounds is the possibility for high-efficiency labelling with gallium-68 quickly at room temperature with high reliability and without the need for product purification, which enables the development of an instant kit-type labelling method. We evaluated its imaging characteristics in patients with neuroendocrine tumours in comparison to [68Ga]Ga-DOTA-TOC. METHODS: 19 patients imaged with [68Ga]Ga-DATA-TOC were retrospectively analysed and uptake in normal tissues was compared with a group of 19 patients imaged with [68Ga]Ga-DOTA-TOC. 10 patients imaged with [68Ga]Ga-DATA-TOC had a history of [68Ga]Ga-DOTA-TOC imaging before and were additionally analysed to obtain biodistribution data of both tracers in the same patients. In 5 patients showing stable disease between both examinations, tumour uptake, lesion detectability and lesion conspicuity of both tracers were evaluated. RESULTS: Uptake of [68Ga]Ga-DATA-TOC in normal organs with expression of the somatostatin receptor was 25-47% lower compared to [68Ga]Ga-DOTA-TOC. Background of [68Ga]Ga-DATA-TOC was 40-41% lower in the liver. A higher retention of [68Ga]Ga-DATA-TOC was observed in the blood (up to 67%) and in the lungs (up to 44%). Tumour uptake (SUV) was 22-31% lower for [68Ga]Ga-DATA-TOC. However, no significant differences were observed for tumour-to-background ratios and lesion detectability. Regarding liver metastases, [68Ga]Ga-DATA-TOC uptake (SUV) reached 69-73% of [68Ga]Ga-DOTA-TOC uptake, but tumour-to-background ratios of [68Ga]Ga-DATA-TOC were 105-110% of [68Ga]Ga-DOTA-TOC ratios. CONCLUSIONS, ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: We demonstrated the feasibility of the new PET tracer [68Ga]Ga-DATA-TOC for imaging of patients with neuroendocrine tumours, showing a comparable performance to [68Ga]Ga-DOTA-TOC. [68Ga]Ga-DATA-TOC has the potential for development of an instant kit-type labelling method at room temperature similar to 99mTc-labelled radiopharmaceuticals, which might help to increase the availability of 68Ga-labelled somatostatin analogues for clinical routine use.

Isolation of the ARO1 cluster gene of Saccharomyces cerevisiae.

The AROl cluster gene was isolated by complementation in Saccharomyces cerevisiae after transformation with a comprehensive yeast DNA library of BamHI restriction fragments inserted into the shuttle vector YEp13. Most of the transformants exhibited the expected episomal inheritance of the ARO+ phenotype; however, one stable transformant has been shown to be an integration of the AROl fragment and the vector YEp13 at the arol locus. The insert containing AROl is a 17.2-kilobase pair (kbp) BamHI fragment which complements both nonsense and missense alleles of arol. Subcloning by Sau3AI partial digestion further locates the AROl segment to a 6.2-kbp region. An autonomously replicating sequence (ars) was found on the 17.2-kbp fragment. Yeast arol mutants transformed with the AROl episome express 5 to 12 times the normal level of the five AROl enzyme activities and possess elevated amounts of the AROl protein. The yeast AROl fragment also complemented aroA, aroB, aroD, and aroE mutants of Escherichia coli. The expression of AROl in both S. cerevisiae and E. coli was independent of the orientation of the fragment with respect to the vector.

Kynureninase-type enzymes and the evolution of the aerobic tryptophan-to-nicotinamide adenine dinucleotide pathway.

Kynureninase-type (L-kynurenine hydrolase, EC 3.7.1.3) activity has been found to be present in the livers of fish, amphibia, reptiles, and birds. In addition to past information concerning this enzyme activity in mammalian liver, it is now clear that all the major classes of vertebrates carry a highly specialized kynureninase-type enzyme, which we have termed a hydroxykynureninase. To compare the reactivities of these enzymes with L-kynurenine and L-3-hydroxykynurenine, ratios of tau values (Km/V) were used. Based on this comparison, the bacterium Pseudomonas fluorescens carries the most efficient kynureninase, whereas the amphibian Xenopus laevis has the most efficient hydroxykynureniase. In these two cases, the ratio of tau values differs by a factor of 38 000. It is hypothesized that the tryptophan-to-nicotinamide adenine dinucleotide biosynthetic pathway evolved from a catabolic system of enzymes, and that the differences observed in the kynureninase-type enzymes between lower and higher organisms reflect the specialization of the function of these enzymes from a strictly catabolic role to an anabolic one during the course of evolution.

Nucleotide sequence and deduced amino acid sequence of a coleopteran-active delta-endotoxin gene from Bacillus thuringiensis subsp. san diego.

A gene from Bacillus thuringiensis subsp. san diego that is responsible for a delta-endotoxin active against Colorado potato beetle and some other Coleoptera was sequenced and shown to have surprising regional homology with both lepidopteran and dipteran active delta-endotoxins from other strains of B. thuringiensis. Unlike the lepidopteran active toxins from B. thuringiensis subsp. kurstaki that exist as approx. 130-kDa protoxins and form bipyramidal crystalline inclusions, the coleopteran toxic protein forms a square-shaped crystal composed of an approx. 65-kDa protein. Comparisons of the gene sequences encoding the active portions of these protoxins indicate conservation of N-terminal hydrophilic and hydrophobic regions, and suggest a distant ancestral origin for these insecticidal proteins.

Imaging of hypoxia using PET and MRI.

Tumor hypoxia is the result of an inadequate supply of oxygen to tumor cells which can be caused by multiple factors. It is associated with aggressive local tumor growth and invasion, increased risk of metastasis, higher resistance to radiotherapy (RT) and chemotherapy, overall resulting in a poor clinical prognosis. Many locally advanced solid tumors may exhibit hypoxic and/or anoxic tissue areas that are heterogeneously distributed within the tumor mass. As hypoxia is a negative prognostic factor concerning response to radiotherapy and chemotherapy, in vivo measurement of tumor hypoxia could be helpful to identify patients with worse prognosis or patients that could benefit from appropriate treatments such as intensity modulated radiotherapy (IMRT) that may accurately conform the dose distribution to small intratumoral regions showing differences in the oxygen level. A manifold of different methods to assess the oxygen tension (pO2) in tissues have been developed, each of them offering advantages as well as drawbacks. They range from invasive direct measurement techniques of the pO2 in tissue by using a polarographic electrode, to non-invasive imaging techniques such as positron emission tomography (PET) or magnetic resonance imaging (MRI). This article provides an overview over the various methods, with a particular emphasis on PET and MRI for imaging of hypoxia, and reviews their performance in preclinical and clinical studies.

Molecular imaging of αvß3 expression in cancer patients.

Angiogenesis, the formation of new blood vessels, is a key process in the growth of solid tumors. Thus this process could potentially be utilized for diagnosis of malignancies by molecular imaging on the one hand and for tumor treatment on the other hand. Imaging of angiogenesis has become increasingly important with the rising use of targeted antiangiogenic therapies, like bevacizumab (Avastin). Non-invasive assessment of angiogenic activity is in this respect interesting e.g. for response assessment of such targeted antiangiogenic therapies. Several methods have been employed for imaging of angiogenesis in vivo. Mostly these approaches measure physical parameters of the tissue, e.g. blood flow, blood volume and vessel permeability. Another approach of angiogenesis imaging is imaging of specific molecular markers of the angiogenic cascade. Integrins, like αvß3, but also αvß5 and α5ß1, play a central role in the angiogenic process and integrin αvß3 binding substances can be used as imaging probes to assess integrin expression. For clinical applications, the use of radiolabeled integrin binding substances is favorable, as radiotracers can be detected with very high sensitivities in vivo. As the radiotracer approach for molecular imaging of αvß3 expression is by now the only approach used in the clinical setting, it will be the focus of this review. We will summarize the current data on imaging of αvß3 expression in the clinical arena using single photon emission computed tomography (SPECT) and positron emission tomography (PET). Moreover, an outlook will be presented on potential clinical applications of imaging of αvß3 expression.

Current applied recombinant DNA projects.

The techniques of genetic engineering are many and its potential vast. However, applications requiring the release of recombinant DNA-containing organisms have been limited in scope. This article reviews the recent and already controversial history of this new foray into the use of modern biotechnology, focusing on current projects in the United States which are now in the initial testing stages for commercial development.

Influence of an aggregated multienzyme system on transient time: kinetic evidence for compartmentation by an aromatic-amino-acid synthesizing complex of Neurospora crassa.

The aromatic complex of Neurospora crassa is an aggregated multienzyme system which catalyzes five consecutive reactions in the central pathway leading to the biosynthesis of the aromatic amino acids. In an attempt to understand the physiological importance of this complex in particular, as well as the importance of cellular organization of enzyme systems in general, we have isolated the complex and have begun to characterize its catalytic properties. Optimum conditions for the assay of the overall 5-step reaction catalyzed by the partially purified complex have been determined. An analog computer was programmed to represent an unaggregated system of five enzymes with rate constants identical to those found for the constituent enzymes of the complex. By direct comparison, it was shown that the lags (transient times) obtained for the overall reaction were 10-15 times longer for the hypothetical unaggregated system than for the complex. We conclude from these data that the aggregated multienzyme system compartmentalizes intermediate substrates during the course of the overall reaction. We suggest that, in addition to "channeling" intermediates of competing pathways, reduction of the transient time may be an important consequence of the containment of intermediates within a physically associated enzyme sequence. The fact that the aromatic complex exhibits a second catalytic property unique to aggregated enzyme systems, "coordinate activation" [Welch, G.R. & Gaertner, F.H. (1975) Arch. Biochem. Biophys., in press] indicates that the physical association of these enzymes may have more than one physiological function.

Kynureninase-Type enzymes of Penicillum roqueforti, Aspergillus niger, Rhizopus stolonifer, and Pseudomonas fluorescens: further evidence for distinct kynureninase and hydroxykynureninase activities.

The kynureninase-type enzymes of three fungi and one bacterium were isolated and examined kinetically for their ability to catalyze the hydrolysis of L-kynurenine and L-3-hydroxykynurenine. The phycomycete Rhizopus stolonifer was found to contain a single, constitutive enzyme with Km for L-3-hydroxykynurenine and L-kynurenine of 6.67 times 10-minus 6 and 2.5 times 10-minus 4 M, respectively. The ascomycetes Aspergillus niger and Penicillium roqueforti each contain an enzyme, induced by L-tryptophan, with similar Km for L-3-hydroxykynurenine and L-kynurenine ranging from 5.9 times 10-minus 5 to 14.3 times 10-minus 5 M, as well as a constitutive enzyme with Km for the two substrates of similar to 4 times 10-minus 6 M and 10-minus 4 M. The bacterium Pseudomonas fluorescens has a single, inducible enzyme with Km for L-3-hydroxykynurenine and L-kynurenine of 5 times 10-minus 4 and 7 times 10-minus 5 M. In addition, significant differences in maximal velocities (Vmax) were observed in two cases. The Vmax of the inducible activity from P. fluorescens was 4.5 times greater for L-kynurenine than L-3-hydroxykynurenine, whereas the Vmax of the constitutive activity from R. stolonifer was 2.5 times greater for L-3-hydroxykynurenine. It is concluded (i) that the constitutive activities are hydroxykynureninases involved in the biosynthesis of nicotinamide adenine dinucleotide from L-tryptophan, (ii) that the inducible activities are kynureninases involved in the catabolism of L-tryptophan to anthranilate, and (iii) that R. stolonifer and P. fluorescens, respectively, carry the most specific examples of each type of enzyme.

Distinct kynureninase and hydroxykynureninase activities in microorganisms: occurrence and properties of a single physiologically discrete enzyme in yeast.

(i) Saccharomyces cerevisiae grown in the presence of 1.0 mM l-tryptophan slowly excreted fluorescent material that was chromatographically identifiable as 3-hydroxyanthranilate but did not excrete detectable amounts of anthranilate nor rapidly deplete the medium of l-tryptophan. Under similar growth conditions, Neurospora crassa rapidly excretes anthranilate and rapidly depletes the medium of l-tryptophan. (ii) Chromatographic analysis of crude extracts from yeast revealed a single kynureninase-type enzyme whose synthesis was not measurably affected by the presence of tryptophan in the medium. Previous studies have provided evidence for two kynureninase-type enzymes in N. crassa, an inducible kynureninase and a constitutive hydroxykynureninase. (iii) Kinetic analysis of the partially purified yeast enzyme provided Michaelis constants for l-3-hydroxykynurenine and l-kynurenine of 6.7 x 10(-6) and 5.4 x 10(-4) M, respectively. This and other kinetic properties of the yeast enzyme are comparable to those reported for the constitutive enzyme from N. crassa. (iv) These findings suggest that S. cerevisiae has in common with N. crassa the biosynthetic enzyme hydroxykynureninase but lacks the catabolic enzyme kynureninase. Therefore, it can be predicted that, unlike N. crassa, S. cerevisiae does not carry out the tryptophan-anthranilate cycle. Distinct kynureninase-type enzymes may exist in other microorganisms and in mammals.

Hydroxykynureninase and the excretion of 3-hydroxyanthranilate by yeast.

A comparative analysis of the kynureninase-type activity found in various organisms has demonstrated two forms of enzyme. One, inducible by tryptophan, has a relatively low Km for L-kynurenine, and is found in microorganisms such as Pseudomonas fluorescens and Neurospora crassa. The other, unaffected by tryptophan, has a low Km for L-3-hydroxykynurenine and is found in a wide variety of organisms, including molds, amphibia, birds and mammals. The yeast Saccharomyces cerevisiae lacks the inducible kynureninase but contains the constitutive enzyme termed an hydroxykynureninase. As a result, the yeast, unlike M. crassa, excretes 3-hydroxyanthranilate in response to L-tryptophan. However, initial studies indicate that little if any 3-hydroxyanthranilate accumulates in beer, wine or bread. Although 3-hydroxyanthranilate is suspect as an endogenous carcinogen, its carcinogenicity as an exogenous agent has not been shown.