[52Mn]Mn-BPPA-Trastuzumab: A Promising HER2-Specific PET Radiotracer.

This study aimed to develop a novel radiotracer using trastuzumab and the long-lived [52Mn]Mn isotope for HER2-targeted therapy selection and monitoring. A new Mn(II) chelator, BPPA, synthesized from a rigid bispyclen platform possessing a picolinate pendant arm, formed a stable and inert Mn(II) complex with favorable relaxation properties. BPPA was converted into a bifunctional chelator (BFC), conjugated to trastuzumab, and labeled with [52Mn]Mn isotope. In comparison to DOTA-GA-trastuzumab, the BPPA-trastuzumab conjugate exhibits a labeling efficiency with [52Mn]Mn approximately 2 orders of magnitude higher. In female CB17 SCID mice bearing 4T1 (HER2-) and MDA-MB-HER2+ (HER2+) xenografts, [52Mn]Mn-BPPA-trastuzumab demonstrated superior uptake in HER2+ cells on day 3, with a 3-4 fold difference observed on day 7. Overall, the hexadentate BPPA chelator proves to be exceptional in binding Mn(II). Upon coupling with trastuzumab as a BFC ligand, it becomes an excellent imaging probe for HER2-positive tumors. [52Mn]Mn-BPPA-trastuzumab enables an extended imaging time window and earlier detection of HER2-positive tumors with superior tumor-to-background contrast.

Do budget constraints limit access to health care? Evidence from PCI treatments in Hungary.

Under Hungary's single payer health care system, hospitals face an annual budget cap on most of their diagnoses-related group based reimbursements. In July 2012, percutaneous coronary intervention (PCI) treatments of acute myocardial infarction were exempted from that hospital level budget cap. We use countrywide individual-level patient data from 2009 to 2015 to map the effect of such a quasi-experimental change in monetary incentives on health provider decisions and health outcomes. We find that direct admissions into PCI-capable hospitals increase, especially in central Hungary, where there are several hospitals which can compete for patients. The proportion of PCI treatments at PCI-capable hospitals, however, does not increase, and neither does the number of patient transfers from non-PCI hospitals to PCI-capable ones. We conclude that only patient pathways, plausibly influenced by hospital management, were affected by the shift in incentives, while physicians' treatment decisions were not. While average length of stay decreased, we do not find any effect on 30-day readmissions or in-hospital mortality.

Physico-Chemical Characterization of a Highly Rigid Gd(III) Complex Formed with a Phenanthroline Derivative Ligand.

The discovery of the nephrogenic systemic fibrosis (NSF) and its link with the in vivo dissociation of certain Gd(III)-based contrast agents (CAs) applied in the magnetic resonance imaging (MRI) induced a still growing research to replace the compromised agents with safer alternatives. In recent years, several ligands were designed to exploit the luminescence properties of the lanthanides, containing structurally constrained aromatic moieties, which may form rigid Gd(III) complexes. One of these ligands is (1,10-phenanthroline-2,9-diyl)bis(methyliminodiacetic acid) (H4FENTA) designed and synthesized to sensitize Eu(III) and Tb(III) luminescence. Our results show that the conditional stability of the [Gd(FENTA)]- chelate calculated for physiological pH (pGd = 19.7) is similar to those determined for [Gd(DTPA)]2- (pGd = 19.4) and [Gd(DOTA)]- (pGd = 20.1), routinely used in the clinical practice. The [Gd(FENTA)]- complex is remarkably inert with respect to its dissociation (t1/2 = 872 days at pH = 7 and 25 °C); furthermore, its relaxivity values determined at different field strengths and temperatures (e.g., r1p = 4.3 mM-1s-1at 60 MHz and 37 °C) are ca. one unit higher than those of [Gd(DTPA)]2- (r1p = 3.4 mM-1 s-1) and [Gd(DOTA)]- (r1p = 3.1 mM-1 s-1) under the same conditions. Moreover, significant improvement on the relaxivity was observed in the presence of serum proteins (r1p = 6.9 mM-1 s-1 at 60 MHz and 37 °C). The luminescence lifetimes recorded in H2O and D2O solutions indicate the presence of a water molecule (q = 1) in the inner sphere of the complex directly coordinated to the metal ion, possessing a relatively high water exchange rate (kex298 = 29(2) × 106 s-1). The acceleration of the water exchange can be explained by the steric compression around the water binding site due to the rigid structure of the complex, which was supported by DFT calculations. On the basis of these results, ligands containing a phenanthroline platform have great potential in the design of safer Gd(III) agents for MRI.

Heterogeneous impact of the COVID-19 pandemic on lung, colorectal and breast cancer incidence in Hungary: results from time series and panel data models.

OBJECTIVE: During the COVID-19 pandemic, health system resources were reallocated to provide care for patients with COVID-19, limiting access for others. Patients themselves also constrained their visits to healthcare providers. In this study, we analysed the heterogeneous effects of the pandemic on the new diagnoses of lung, colorectal and breast cancer in Hungary. DESIGN: Time series and panel models of quarterly administrative data, disaggregated by gender, age group and district of residence. PARTICIPANTS: Data for the whole population of Hungary between the first quarter of 2017 and the second quarter of 2021. MAIN OUTCOME MEASURES: Number of patients newly diagnosed with lung, colorectal and breast cancer, defined as those who were hospitalised with the appropriate primary International Classification of Diseases Tenth Revision diagnosis code but had not had hospital encounters with such a code within the previous 5 years. RESULTS: The incidence of lung, colorectal and breast cancer decreased by 14.4% (95% CI 10.8% to 17.8%), 19.9% (95% CI 12.2% to 26.9%) and 15.5% (95% CI 2.5% to 27.0%), respectively, during the examined period of the pandemic, with different time patterns across cancer types. The incidence decreased more among people at least 65 years old than among the younger (p<0.05 for lung cancer and p<0.1 for colorectal cancer). At the district level, both the previously negative income gap in lung cancer incidence and the previously positive income gap in breast cancer incidence significantly narrowed during the pandemic (p<0.05). CONCLUSIONS: The decline in new cancer diagnoses, caused by a combination of supply-side and demand-side factors, suggests that some cancer cases have remained hidden. It calls for action by policy makers to engage individuals with high risk of cancer more in accessing healthcare services, to diagnose the disease early and to prepare for effective management of patient pathways from diagnosis to survival or end-of-life care.

Effects of lower screening activity during the COVID-19 pandemic on breast cancer patient pathways: Evidence from the age cut-off of organized screening.

We examined the effects of the COVID-19 pandemic on the screening, diagnosis and treatment of breast cancer in Hungary based on administrative data until June 2021, covering three pandemic waves. After correcting for trend and seasonality, the number of mammography examinations decreased by 68% in 2020q2, was around its usual level in 2020q3 and was reduced by 20-35% throughout 2020q4-2021q2. The reduction was caused by a combination of supply-side (temporary suspensions of screening) and demand-side (lower screening participation during the pandemic waves) factors. The number of new breast cancer diagnoses and mastectomy surgeries responded with a lag, and were below their usual level by 15-30% in all quarters between 2020q2 and 2021q2, apart from 2020q4, when there was no significant difference. Using a regression discontinuity framework, we found that the partial mastectomy rate (indicative of early diagnosis) dropped more substantially in 2020q2 in the 61-65 years old age group that was just below the age cut-off of organized screening than in the 66-70 years old age group, and this difference was partially offset in 2021q1. We suggest that policymakers need to motivate the target population (by providing both information and incentives) to catch up on missed screenings.

Rigidified Derivative of the Non-macrocyclic Ligand H4OCTAPA for Stable Lanthanide(III) Complexation.

The stability constants of lanthanide complexes with the potentially octadentate ligand CHXOCTAPA4-, which contains a rigid 1,2-diaminocyclohexane scaffold functionalized with two acetate and two picolinate pendant arms, reveal the formation of stable complexes [log KLaL = 17.82(1) and log KYbL = 19.65(1)]. Luminescence studies on the Eu3+ and Tb3+ analogues evidenced rather high emission quantum yields of 3.4 and 11%, respectively. The emission lifetimes recorded in H2O and D2O solutions indicate the presence of a water molecule coordinated to the metal ion. 1H nuclear magnetic relaxation dispersion profiles and 17O NMR chemical shift and relaxation measurements point to a rather low water exchange rate of the coordinated water molecule (kex298 = 1.58 × 106 s-1) and relatively high relaxivities of 5.6 and 4.5 mM-1 s-1 at 20 MHz and 25 and 37 °C, respectively. Density functional theory calculations and analysis of the paramagnetic shifts induced by Yb3+ indicate that the complexes adopt an unprecedented cis geometry with the two picolinate groups situated on the same side of the coordination sphere. Dissociation kinetics experiments were conducted by investigating the exchange reactions of LuL occurring with Cu2+. The results confirmed the beneficial effect of the rigid cyclohexyl group on the inertness of the Lu3+ complex. Complex dissociation occurs following proton- and metal-assisted pathways. The latter is relatively efficient at neutral pH, thanks to the formation of a heterodinuclear hydroxo complex.

Complexation of Mn(II) by Rigid Pyclen Diacetates: Equilibrium, Kinetic, Relaxometric, Density Functional Theory, and Superoxide Dismutase Activity Studies.

We report the Mn(II) complexes with two pyclen-based ligands (pyclen = 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene) functionalized with acetate pendant arms at either positions 3,6 (3,6-PC2A) or 3,9 (3,9-PC2A) of the macrocyclic fragment. The 3,6-PC2A ligand was synthesized in five steps from pyclen oxalate by protecting one of the secondary amine groups of pyclen using Alloc protecting chemistry. The complex with 3,9-PC2A is characterized by a higher thermodynamic stability [log KMnL = 17.09(2)] than the 3,6-PC2A analogue [log KMnL = 15.53(1); 0.15 M NaCl]. Both complexes contain a water molecule coordinated to the metal ion, which results in relatively high 1H relaxivities (r1p = 2.72 and 2.91 mM-1 s-1 for the complexes with 3,6-PC2A and 3,9-PC2A, respectively, at 25 °C and 0.49 T). The coordinated water molecule displays fast exchange kinetics with the bulk in both cases; the rates (kex298) are 140 × 106 and 126 × 106 s-1 for [Mn(3,6-PC2A)(H2O)] and [Mn(3,9-PC2A)(H2O)], respectively. The two complexes were found to be remarkably inert with respect to their dissociation, with half-lives of 63 and 21 h, respectively, at pH = 7.4 in the presence of excess Cu(II). The r1p values recorded in blood serum remain constant at least over a period of 120 h. Cyclic voltammetry experiments show irreversible oxidation features shifted to higher potentials with respect to [Mn(EDTA)(H2O)]2- (H4EDTA = ethylenediaminetetraacetic acid) and [Mn(PhDTA)(H2O)]2- (H4PhDTA = phenylenediamine-N,N,N',N'-tetraacetic acid), indicating that the PC2A complexes reported here have a lower tendency to stabilize Mn(III). The superoxide dismutase activity of the Mn(II) complexes was tested using the xanthine/xanthine oxidase/p-nitro blue tetrazolium chloride assay at pH = 7.8. The Mn(II) complexes of 3,6-PC2A and 3,9-PC2A are capable of assisting decomposition of the superoxide anion radical. The kinetic rate constant of the complex of 3,9-PC2A is smaller by 1 order of magnitude than that of 3,6-PC2A.

Mn(II)-Based MRI Contrast Agent Candidate for Vascular Imaging.

Toxicity concerns related to Gd(III)-based magnetic resonance imaging (MRI) agents prompted an intensive research toward their replacement by complexes of essential metal ions, like Mn(II). Here, we report a macrocyclic chelate, [Mn(PC2A-BP)], which possesses high thermodynamic stability (log KMnL = 14.86 and pMn=8.35) and kinetic inertness (t1/2pH=7.4 = 286.2 h) as well as as remarkable relaxivity (r1p = 23.5 mM-1 s-1, 0.49 T, 37 °C) in the presence of human serum albumin, allowing a significant MRI signal intensity increase in the vasculature even at low dose (25 µmol/kg) of the complex.

Picolinate-appended tacn complexes for bimodal imaging: Radiolabeling, relaxivity, photophysical and electrochemical studies.

Based on our previous works involving two 1,4,7-triazacyclononane (tacn)-based ligands Hno2py1pa (1-Picolinic acid-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane) and Hno1pa (1-Picolinic acid-1,4,7-triazacyclononane), we report here the synthesis of analogues bearing picolinate-based π-conjugated ILCT (Intra-Ligand Charge Transfer) transition antenna (HL1, HL2), using regiospecific N-functionalization of the tacn skeleton and their related transition metal complexes (e.g. Cu2+, Zn2+ and Mn2+). Coordination properties as well as their photophysical and electrochemical properties were investigated in order to quantify the impact of such antenna on the luminescent or relaxometric properties of the complexes. The spectroscopic properties of the targeted ligands and metal complexes have been studied using UV-Vis absorption and fluorescence spectrocopies. While the zinc complex formed with HL1 possesses a moderate quantum yield of 5%, complexation of Cu2+ led to an extinction of the luminescence putatively attributed to a photo-induced electron transfer, as supported by spectroscopic and electrochemical evidences. The [Mn(L2)]+ complex is characterized by a fluorescence quantum yield close to 8% in CH2Cl2. The potential interest of such systems as bimodal probes has been assessed from radiolabeling experiments conducted on HL1 and 64Cu2+ as well as confocal microscopy analyses and from relaxometric studies carried out on the cationic [Mn(L2)]+ complex. These results showed that HL1 can be used for radiolabeling, with a radiochemical conversion of 40% in 15 min at 100 °C. Finally, the relaxivity values obtained for [Mn(L2)]+, r1p = 4.80 mM-1·s-1 and r2p = 8.72 mM-1·s-1, make the Mn(II) complex an ideal candidate as a probe for Magnetic Resonance Imaging.

The closer the better: does better access to outpatient care prevent hospitalization?

In 2010-2012, new outpatient service locations were established in poor Hungarian micro-regions. We exploit this quasi-experiment to estimate the extent of substitution between outpatient and inpatient care. Fixed-effects Poisson models on individual-level panel data for years 2008-2015 show that the number of outpatient visits increased by 19% and the number of inpatient stays decreased by 1.6% as a result, driven by a marked reduction of potentially avoidable hospitalization (PAH) (5%). In our dynamic specification, PAH effects occur in the year after the treatment, whereas non-PAH only decreases with a multi-year lag. The instrumental variable estimates suggest that a one euro increase in outpatient care expenditures produces a 0.6 euro decrease in inpatient care expenditures. Our results (1) strengthen the claim that bringing outpatient care closer to a previously underserved population yields considerable health benefits, and (2) suggest that there is a strong substitution element between outpatient and inpatient care.

Effects of Geographical Accessibility on the Use of Outpatient Care Services: Quasi-Experimental Evidence from Panel Count Data.

In 2010-2012, new outpatient service locations were established in Hungarian micro-regions, which had lacked such capacities before. We exploit this quasi-experiment to estimate the effect of geographical accessibility on outpatient case numbers using both individual-level and semi-aggregate panel data. We find a 24-27 per cent increase of case numbers as a result of the establishments. Our specialty-by-specialty estimates imply that a 1-min reduction of travel time to the nearest outpatient unit increases case numbers for example by 0.9 per cent in internal care and 3.1 per cent in rheumatology. The size of the new outpatient capacities has a separate effect, raising the possibility of the presence of supplier-induced demand. By combining a fixed-effects logit and a fixed-effects truncated Poisson estimator, we decompose the effects into increases in the probability of ever visiting a doctor on the one hand and an increase of the frequency of visits on the other hand. We find that new visits were dominant in the vast majority of specialties, whereas both margins were important for example in rheumatology. Finally, we demonstrate the usefulness of the fixed-effects truncated Poisson estimator in modelling count data by examining its robustness by simulations.

Phospholipid barrier to fibrinolysis: role for the anionic polar head charge and the gel phase crystalline structure.

The massive presence of phospholipids is demonstrated in frozen sections of human arterial thrombi. Purified platelet phospholipids and synthetic phospholipids retard in vitro tissue-type plasminogen activator (tPA)-induced fibrinolysis through effects on plasminogen activation and plasmin function. The inhibition of plasminogen activation on the surface of fibrin correlates with the fraction of anionic phospholipid. The phospholipids decrease the amount of tPA penetrating into the clot by 75% and the depth of the reactive surface layer occupied by the activator by up to 30%, whereas for plasmin both of these parameters decrease by approximately 50%. The phospholipids are not only a diffusion barrier, they also bind the components of the fibrinolytic system. Isothermal titration calorimetry shows binding characterized with dissociation constants in the range 0.35-7.64 microm for plasmin and tPA (lower values with more negative phospholipids). The interactions are endothermic and thermodynamically driven by an increase in entropy, probably caused by the rearrangements in the ordered gel structure of the phospholipids (in line with the stronger inhibition at gel phase temperatures compared with liquid crystalline phase temperatures). These findings show a phospholipid barrier, which should be overcome during lysis of arterial thrombi.

Myosin: a noncovalent stabilizer of fibrin in the process of clot dissolution.

Myosin modulates the fibrinolytic process as a cofactor of the tissue plasminogen activator and as a substrate of plasmin. We report now that myosin is present in arterial thrombi and it forms reversible noncovalent complexes with fibrinogen and fibrin with equilibrium dissociation constants in the micromolar range (1.70 and 0.94 microM, respectively). Competition studies using a peptide inhibitor of fibrin polymerization (glycl-prolyl-arginyl-proline [GPRP]) indicate that myosin interacts with domains common in fibrinogen and fibrin and this interaction is independent of the GPRP-binding polymerization site in the fibrinogen molecule. An association rate constant of 1.81 x 10(2) M(-1) x s(-1) and a dissociation rate constant of 3.07 x 10(-4) s(-1) are determined for the fibrinogen-myosin interaction. Surface plasmon resonance studies indicate that fibrin serves as a matrix core for myosin aggregation. The fibrin clots equilibrated with myosin are stabilized against dissolution initiated by plasminogen and tissue-type plasminogen activator (tPA) or urokinase (at fibrin monomer-myosin molar ratio as high as 30) and by plasmin under static and flow conditions (at fibrin monomer-myosin molar ratio lower than 15). Myosin exerts similar effects on the tPA-induced dissolution of blood plasma clots. Covalent modification involving factor XIIIa does not contribute to this stabilizing effect; myosin is not covalently attached to the clot by the time of complete cross-linking of fibrin. Thus, our in vitro data suggest that myosin detected in arterial thrombi binds to the polymerized fibrin, in the bound form its tPA-cofactor properties are masked, and the myosin fibrin clot is relatively resistant to plasmin.

Immunoglobulin G from patients with antiphospholipid syndrome impairs the fibrin dissolution with plasmin.

Immunoglobulin G (IgG) isolated from normal human blood plasma stabilizes the structure of perfused crosslinked fibrin and prolongs the time for its dissolution with plasmin, when the fibrin surface is exposed to 500 s(-1) shear rate flow. The IgG from patients suffering in antiphospholipid syndrome with thrombotic complications exerts even stronger antifibrinolytic effect. A patient, whose IgG does not affect the fibrin dissolution with plasmin, displays a bleeding tendency. The shear stress-induced disassembly of the fibrin clots containing IgGs with antifibrinolytic potency occurs at a much more advanced stage of fibrin digestion, as evidenced by the electrophoretic pattern of the ureatreated samples. The antifibrinolytic effects are also produced under static conditions and these are caused by the variable portion of the IgG molecules (fragment Fab), whereas the constant part (fragment Fc) has no inhibitory effect. The IgGs with antifibrinolytic properties do not affect directly the plasmin activity in amidolytic assay, but the IgGs from APS patients obliterate the competition of the fibrin and the peptidyl-p-nitroanilide for the protease in the same assay system suggesting interference of the IgGs with the plasmin action on the fibrin substrate. Thus, the correlation of the clinical symptoms with the effect of the isolated IgG on the dissolution of perfused fibrin clots supports a physiological and a pathological role of IgG in the fibrinolytic process related to the variability of the cross-reactions of immunoglobulins with fibrin, fibrin degradation products or fibrin-plasmin complexes.