Teaching nuclear medicine in the pandemic—a new challenge for the faculty

European Journal of Nuclear Medicine and Molecular Imaging -     

Prevalence of malnutrition in systemic sclerosis patients assessed by different diagnostic tools

Clinical Rheumatology - Gastrointestinal complaints of scleroderma (SS) patients are risk factors for impaired nutritional status, so insightful assessment is necessary. The aim was comparison of...     

PACAP38 and PACAP6-38 Exert Cytotoxic Activity Against Human Retinoblastoma Y79 Cells

Pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional neuropeptide expression of which has been found in various tumors of the brain and peripheral organs. Despite numerous studies, the exact role the peptide plays in the development and progression of tumors is not fully understood. In the present study, we investigated the effect of PACAP on human retinoblastoma Y79 cell viability. We found that both PACAP38 and PACAP6-38, a selective PAC₁ receptor antagonist, did not affect Y79 cell viability at nanomolar concentrations, but when used at 1–5 μM potently reduced cell survival in a dose-dependent manner. PACAP27 and maxadilan, a high affinity agonist of PAC₁ receptors, had negligible effects. Two membrane-penetrating analogs of PACAP38 inactive at PAC₁/VPAC receptors, [Disc⁶]PACAP38 and FITC-Ahx-PACAP11-38, also decreased viability of Y79 cells, albeit with lower potency than PACAP38. The cytotoxic effect of PACAP38 was augmented by p38, MEK1/2, and JNK inhibitors, indicating that high concentrations of the peptide might decrease the activity of these kinases, leading to cell death. It is suggested that the cytotoxic activity of PACAP38 and PACAP6-38 against human retinoblastoma Y79 cell line may result from their interaction with target sites other than PAC₁ and VPAC receptors, but this is yet unknown.     

Are synchronous and metachronous bilateral breast cancers different? An immunohistochemical analysis aimed at intrinsic tumor phenotype

The biology and pathomechanism of bilateral breast cancers is not fully understood. We compared the morphological and immunohistochemical characteristics of primary tumors in patients with synchronous bilateral breast cancers and metachronous bilateral breast cancers, with special focus on intrinsic tumor phenotype. Methods: Tumor morphology and expression of 8 immunohistochemical markers were assessed in tissue microarrays containing primary breast tumor cores from 113 metachronous bilateral breast cancers and 61 synchronous bilateral breast cancers. Analyzed markers included hormone receptors (estrogen receptor, progesterone receptor), HER2, Ki67, cytokeratin 5/6, E-cadherin, vimentin and epidermal growth factor receptor. Cutoff levels are provided in the table. Results: Metachronous bilateral breast cancers tumors had lower estrogen receptor expression (p=0.047) and higher expression of cytokeratin 5/6 (p=0.017) and of vimentin (p=0.008); in multivariate analysis only vimentin retained the significance (p=0.01). Ten (13%) and 11 (26%) of metachronous bilateral breast cancers and synchronous bilateral breast cancers had luminal A phenotype, 39 (50%) and 15 (36%) were luminal B HER2-negative, 13 (17%) and 12 (28%) - luminal B HER2-positive, 3 (4%) and 2 (5%) - HER2-positive (not luminal), and 12 (16%) and 2 (5%) had triple negative phenotype (p=0.07). Conclusion: Metachronous bilateral breast cancers, compared to synchronous bilateral breast cancers, are characterized by more aggressive phenotype, expressed by lower expression of estrogen receptor and stronger expression of cytokeratin 5/6 and vimentin; this does not, however, translate into differences in the distribution of intrinsic tumor phenotypes.     

Structure and Properties of Gas-Nitrided,Precipitation-Hardened Martensitic Stainless Steel

Nanoflex stainless steel is a promising material for medical applications. However, improvement of its mechanical properties without compromising its corrosion resistance is still a challenge. In order to investigate the effect of the nitriding process on the corrosion and wear resistance of Sandvik Nanoflex^TM steel, a number of processes were carried out in a gas atmosphere with differing ammonia contents in the temperature range of 425–475 °C for 4 h. The mechanical properties and wear resistance of the layers were tested using the nanoindentation and pin-on-disc methods, respectively. In order to assess corrosion resistance, potentiodynamic tests were carried out in Ringer’s artificial body fluid and in a 3% aqueous solution of sodium chloride. The results are discussed herein with respect to the microstructural characteristics of the layers studied using light and scanning electron microscopy, X-ray diffraction phase analysis and wavelength dispersive X-ray microanalysis. The structure of nitrided layers included three zones: the subsurface zone composed of nitrides and the zones composed of metastable phases, i.e., the S phase (γN) and expanded martensite (αN) with possible precipitates of nitrides. The third zone adjacent to the steel core was enriched with carbon. The nitrided samples showed significant improvement in the wear rate while maintaining good corrosion resistance in comparison to the non-treated steel. We concluded that nitriding should be carried out at a temperature below 450 °C and in an atmosphere containing no more than approximately 50% ammonia in order to avoid nitrides precipitation.     

Fe-Doped Barium Lanthanum Titanate as a Competitor to Other Lead-Free Piezoelectric Ceramics

Multiferroic solid solutions of Ba_1−xLa_xTi_1−x/4O₃ and iron (BLFT) were synthesized using the conventional mixed oxide method. The dependence of the piezoelectric coefficients on Fe content in BLFT ceramics was determined by the quasi-static and resonance method. The results indicate that 0.3 mol% addition of Fe³⁺ ions to the ceramic structure increased the value of the piezoelectric parameter d₃₃ to the maximum of 159 pC/N. This puts BLFT ceramics among other good-quality and lead-free piezoelectric ceramics. A major enhancement of dielectric properties related to the manipulation of Fe content in the barium lanthanum titanate (BLT) ceramics system is reported as well.     

Plasma asymmetric dimethylarginine predicts restenosis after coronary angioplasty

Introduction

Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of endothelial nitric oxide synthase. Asymmetric dimethylarginine may influence the process of restenosis after coronary angioplasty. The aim of the study was to determine if initial plasma ADMA level could predict restenosis after coronary angioplasty and stenting.

Material and methods

The study group consisted of 60 consecutive patients (10 women and 50 men, average age 58.9 ±10.4 years old), who underwent percutaneous coronary angioplasty with bare metal stenting for stable coronary artery disease. All patients underwent follow-up coronary angiography after a 6-month period. Patients were divided into two groups, one with restenosis (n = 22), and the other one without restenosis (n = 38). In addition to measuring acknowledged restenosis risk factors, plasma ADMA level was measured before initial angiography.

Results

Asymmetric dimethylarginine plasma level was significantly higher in the group with restenosis than in the group without restenosis (1.94 ±0.94 µmol/l vs. 0.96 ±0.67 µmol/l; p < 0.05). L-arginine/ADMA ratio was also decreased in the group with restenosis, when compared with the group without restenosis (p < 0.05). Multivariate logistic regression revealed that independent restenosis risk factors were characterised by an initially high ADMA level (p < 0.01), advanced age (p < 0.05) and low level of HDL cholesterol (p < 0.05).

Conclusions

Pre-procedural elevated plasma ADMA level increases the risk of restenosis in patients who underwent coronary angioplasty and stenting with bare metal stents.