Terbium offers 4 clinically interesting radioisotopes with complementary physical decay characteristics: 149 Tb, 152 Tb, 155 Tb, and 161 Tb. The identical chemical characteristics of these radioisotopes allow the preparation of radiopharmaceuticals with identical pharmacokinetics useful for PET ( 152 Tb) and SPECT diagnosis ( 155 Tb) and for a-( 149 Tb) and b 2 -particle ( 161 Tb) therapy. The goal of this proof-of-concept study was to produce all 4 terbium radioisotopes and assess their diagnostic and therapeutic features in vivo when labeled with a folate-based targeting agent. Methods: 161 Tb was produced by irradiation of 160 Gd targets with neutrons at Paul Scherrer Institute or Institut LaueLangevin. After neutron capture, the short-lived 161 Gd decays to 161 Tb. 149 Tb, 152 Tb, and 155 Tb were produced by proton-induced spallation of tantalum targets, followed by an online isotope separation process at ISOLDE/CERN. The isotopes were purified by means of cation exchange chromatography. For the in vivo studies, we used the DOTA-folate conjugate cm09, which binds to folate receptor (FR)-positive KB tumor cells. Therapy experiments with 149 Tb-cm09 and 161 Tb-cm09 were performed in KB tumor-bearing nude mice. Diagnostic PET/ CT ( 152 Tb-cm09) and SPECT/CT ( 155 Tb-cm09 and 161 Tbcm09) studies were performed in the same tumor mouse model. Results: Carrier-free terbium radioisotopes were obtained after purification, with activities ranging from approximately 6 MBq (for 149 Tb) to approximately 15 GBq (for 161 Tb). The radiolabeling of cm09 was achieved in a greater than 96% radiochemical yield for all terbium radioisotopes. Biodistribution studies showed high and specific uptake in FR-positive tumor xenografts (23.8% 6 2.5% at 4 h after injection, 22.0% 6 4.4% at 24 h after injection, and 18.4% 6 1.8% at 48 h after injection). Excellent tumor-to-background ratios at 24 h after injection (tumor to blood, ;15; tumor to liver, ;5.9; and tumor to kidney, ;0.8) allowed the visualization of tumors in mice using PET ( 152 Tb-cm09) and SPECT ( 155 Tb-cm09 and 161 Tb-cm09). Compared with no therapy, a-( 149 Tb-cm09) and b 2 -particle therapy ( 161 Tb-cm09) resulted in a marked delay in tumor growth or even complete remission (33% for 149 Tb-cm09 and 80% for 161 Tb-cm09) and a significantly increased survival. Conclusion: Because of its physical half-lives (T 1/2 ), decay properties, and energies, the lanthanide terbium is one of the few elements that features 4 clinically interesting radioisotopes (Table 1). 149 Tb has a half-life of 4.12 h and emits shortrange a-particles at an energy (E a ) of 3.967 MeV with an intensity of 17%. It is the only a-emitter among radiolanthanides with a suitable half-life for application in radionuclide therapy. 152 Tb (T 1/2 , 17.5 h) emits positrons of an average energy of 1.080 MeV with an intensity of 17%. The radionuclide would be useful for patient-specific dosimetry using PET before the application of therapeutic radiolanthanides. 155 Tb (T 1/2 , 5.32 d) decays by electron cap...

Tumor targeting with folic acid radioconjugates has been proposed as a promising strategy for radionuclide therapy of folate receptor α (FR)-positive cancer. Recently, it was shown that modification of radiofolates with an albumin-binding entity increased the tumor-to-kidney ratios of accumulated radioactivity in mice. The goal of this study was to evaluate the lead compound cm10 and compare it with new albumin-binding folate conjugates. Compound cm12 was designed with a long spacer consisting of a PEG-11 entity, and compound cm13 contained a short alkane chain between the albumin-binding moiety and folic acid. All of the derivatives were labeled with Lu (t = 6.65 days, E = 134 keV; E = 113 keV, 208 keV), a clinically established radionuclide for therapeutic purposes. The evaluation revealed that all of the albumin-binding radiofolates exhibited increased in vitro stability compared with the reference compound (Lu-cm14) without albumin binder. Serum protein binding, determined with an ultrafiltration assay, was high (>88%) for the derivatives with albumin-binding entities. The FR-binding affinity was in the same range (K = 4.0-7.5 nM) for all of the radiofolates, independent of the albumin-binding entity and spacer length. FR-specific uptake was proven in vitro using FR-positive KB tumor cells. In vivo studies with KB-tumor-bearing mice were performed in order to assess the tissue distribution profile of the novel radiofolates. Lu-cm13 showed high tumor uptake at late time points (13.3 ± 2.94% IA/g, 48 h p.i.) and tumor-to-kidney ratios (0.59 ± 0.03, 48 h p.i.) in the same range asLu-cm10 (0.55 ± 0.07, 48 h p.i.). However, the tumor-to-kidney ratio of Lu-cm12 (0.28 ± 0.07, 48 h p.i.) was reduced compared withLu-cm10 and Lu-cm13. The results of this study indicate that the spacer entity between folic acid and the albumin binder is of critical importance with regard to the tissue distribution profile of the radiofolate. The PEG spacer compromised the beneficial effects of the lead compound, but the design with a short alkane spacer appeared to be promising. Future studies will focus on the design of radiofolates with lipophilic and more rigid spacer entities, which may allow a further improvement of their tissue distribution profiles.

IntroductionTriamcinolone acetonide (TA) is used for osteoarthritis management to reduce pain, and pre-clinical studies have shown that TA limits osteophyte formation. Osteophyte formation is known to be facilitated by synovial macrophage activation. TA injections might influence macrophage activation and subsequently reduce osteophytosis. Although widely applied in clinical care, the mechanism through which TA exerts this effect remains unknown. In this animal study, we investigated the in vivo effects of TA injections on macrophage activation, osteophyte development and joint degeneration. Furthermore, in vitro macrophage differentiation experiments were conducted to further explain working mechanisms of TA effects found in vivo.MethodsOsteoarthritis was induced in rat knees using papain injections and a running protocol. Untreated and TA-treated animals were longitudinally monitored for 12 weeks with in vivo micro–computed tomography (μCT) to measure subchondral bone changes. Synovial macrophage activation was measured in vivo using folate receptor β (FRβ)-targeted single-photon emission computed tomography/computed tomography. Articular cartilage was analyzed at 6 and 12 weeks with ex vivo contrast-enhanced μCT and histology. To further explain the outcomes of our in vivo study, TA on macrophages was also studied in vitro. These cultured macrophages were either M1- or M2-activated, and they were analyzed using fluorescence-activated cell sorting for CD163 and FRβ expression as well as for messenger RNA (mRNA) expression of interleukin (IL)-10.ResultsOur in vivo study showed that intra-articular injections with TA strongly enhanced FRβ+ macrophage activation. Despite stimulated macrophage activation, osteophyte formation was fully prevented. There was no beneficial effect of TA against cartilage degradation or subchondral bone sclerosis. In vitro macrophage cultures showed that TA strongly induced monocyte differentiation towards CD163+ and FRβ+ macrophages. Furthermore, TA-stimulated M2 macrophages showed enhanced IL-10 expression at the mRNA level.ConclusionsTA injections potently induce a CD163+- and FRβ+-activated macrophage with anti-inflammatory characteristics such as reduced IL-10 production in vitro and lack of osteophytosis in vivo.

The acrosome reaction was determined in aliquots from ejaculates of 74 patients undergoing in-vitro fertilization at the University of Giessen, Germany, by means of the triple-stain technique. The percentage of acrosome-reacted spermatozoa after low-temperature induction of the acrosome reaction was not significantly related with the fertilization rate (H test, P = 0.693, SJ test, P = 0.366). However, all patients showing < 13.0% acrosome-reacted spermatozoa had poor fertilization rates. Highly significant differences between patients could be detected by correlating the inducibility of the acrosome reaction with the fertilization rate (H test, P = 0.018; SJ test, P = 0.004); patients with high fertilization rates showed a corresponding high inducibility of acrosome reactions. From our results, it is evident that percentages of acrosome-reacted spermatozoa < 13.0% or an inducibility of the acrosome reaction of < 7.5% are indicative of subfertility.

Little is known about the neurobiologic correlates of human personality. On the basis of the key role of the central opioidergic system in addiction and substance abuse, we investigated the relationship between certain personality traits that are supposed to be relevant in addiction and the opioid receptor status in healthy subjects. Methods: We investigated 23 healthy male volunteers who were extensively clinically tested to exclude substance abuse. All of the subjects underwent 1 PET scan with the subtype-nonselective opioidergic radioligand 18 F-fluoroethyldiprenorphine under resting conditions without sensory or cognitive stimulation. Subsequently, the subjects were psychologically tested for the personality traits novelty seeking, harm avoidance, reward dependence, and persistence, according to Cloninger's biosocial model of personality. The binding potential (BP) as a parameter of regional cerebral opioid receptor availability was computed by means of the modified Logan plot using the occipital cortex as a reference region. Further imaging data analysis was performed using statistical parametric mapping; after stereotactic normalization, the correlations were calculated between the regional BP and the psychologic scores on a voxel-by-voxel basis.Results: The correlation analysis between personality dimensions and opioid receptor availability showed a significant (P , 0.001) positive correlation between the scores of reward dependence and the BP of the bilateral ventral striatum with nucleus accumbens (z scores, 4.52 and 4.33, respectively). The additionally performed region-of-interest-based correlation analysis yielded correlation coefficients of r 5 0.84 and r 5 0.81 for the left and right ventral striata, respectively. No further significant correlations were detectable between the other personality dimensions and cerebral opioid receptor binding. Conclusion: In healthy subjects, personality traits, which might be predisposing for addictive behavior, are correlated to the opioidergic neurotransmission in core structures of the human reward system. Thebi ologic basis of human personality continues to be one of the most interesting and challenging issues of psychobiologic research. Different approaches have shown that certain personality traits are related to neurobiologic parameters (1,2). The development of dimensional models of personality enables a more appropriate description of the complexity and heterogeneity of personality; these models of personality might also be more closely related to the underlying neurobiologic substrate.One of the most popular models to describe human personality on a dimensional level is Cloninger's biosocial model of personality (3,4). This model comprises the 4 temperament dimensions novelty seeking, harm avoidance, reward dependence, and persistence and involves automatic, preconceptual responses to perceptual stimuli, most probably reflecting heritable biases in information processing. These dimensions are considered to be stable across time, except for novelty seeking...

Proteinases converting the zymogen protein C (PC) of vertebrates into activated PC have been detected in several snake venoms. Most PC activators have been purified from venom of snake species belonging to the genera of the Agkistrodon complex. Unlike the physiological, thrombin-catalyzed PC activation reaction which requires thrombomodulin as a cofactor, most snake venom activators directly convert the zymogen PC into the catalytically active form which can easily be determined by means of coagulation or chromogenic substrate techniques. Due to this feature, the fast-acting PC activator Protac^® from Agkistrodon contortrix contortrix (southern copperhead snake) venom has found a broad application in diagnostic practice for the determination of disorders in the PC pathway. Recently, screening assays for the PC pathway have been introduced, based on the observation that the PC pathway is probably the most important physiological barrier against thrombosis.

Summary The presence of components of the renin angiotensin system (RAS) and specific receptors of angiotensin II in the female and male reproductive tract supports the hypothesis that reproductive functions may be controlled by RAS. Therefore, the present study investigated the influence of ACE and angiotensins on sperm functions and the sperm–egg interaction. The experiments did not indicate direct effects of ACE on the capacitation process or acrosome reaction. Release of ACE from human spermatozoa during capacitation was not related to their ability to undergo acrosome reaction after stimulation with ionophore. Therefore, ACE release does not seem to be a useful clinical marker for human sperm capacitation. However, decreased binding of human spermatozoa to the oolemma of zona‐free hamster oocytes after inhibition of ACE by captopril indicates that kininase II is involved in sperm–egg interactions. In contrast to other studies, incubation with captopril had no influence on sperm binding to the zona pellucida. Because effects of ACE on sperm–egg interactions but not on capacitation or acrosome reaction were observed, several experiments were performed to study the influence of substrates and products on the acrosome reaction. Angiotensin II induced the acrosome reaction dose‐dependently, whereas angiotensin I had no effect on the acrosome reaction. The effect of angiotensin II on acrosome reaction seems to be calcium‐dependent and mediated by protein kinases. Since a specific type 2 angiotensin II receptor inhibits the acrosome reaction induced by angiotensin II, this subtype of receptors may be present at the surface of sperm heads. Another clue for the presence of type 2 receptors on human spermatozoa is the finding that pertussis toxin did not inhibit the angiotensin II induced acrosome reaction. In contrast to type 1 angiotensin II receptors, type 2 receptors are known to be G‐protein independent.

Macrophage-activating lipopeptide-2 (MALP-2) is a potent inducer of proinflammatory cytokine secretion by macrophages, monocytes, and dendritic cells. MALP-2 was reported to be involved in natural killer (NK) cell activation and ensuing tumor rejection. However, the mechanism of MALP-2-mediated NK cell activation remained unclear. Therefore, we studied the effects of MALP-2 on cultured human NK cells. We found that MALP-2 had no direct effect on NK cells. Instead, MALP-2 acted on monocytes and triggered the release of different molecules such as interleukin (IL)-1β, IL-6, IL-10, IL-12, IL-15, interferon gamma-induced protein (IP-10), and prostaglandin (PG)-E2. Our data show that monocyte-derived IP-10 could significantly induce NK cell cytotoxicity as long as the immunosuppression by PGE2 is specifically inhibited by cyclooxygenase (COX)-2 blockade. In summary, our results show that MALP-2-mediated stimulation of monocytes results in the production of several mediators which, depending on the prevailing conditions, affect the activity of NK cells in various ways. Hence, MALP-2 administration with concurrent blocking of COX-2 can be considered as a promising approach in MALP-2-based adjuvant tumor therapies.