The ROS-generating photosensitizer-free NaYF4:Yb,Tm@SiO2upconverting nanoparticles for photodynamic therapy application.

In this work we adapt rare-earth-ion-doped NaYF4nanoparticles coated with a silicon oxide shell (NaYF4:20%Yb,0.2%Tm@SiO2) for biological and medical applications (for example, imaging of cancer cells and therapy at the nano level). The wide upconversion emission range under 980 nm excitation allows one to use the nanoparticles for cancer cell (4T1) photodynamic therapy (PDT) without a photosensitizer. The reactive oxygen species (ROS) are generated by Tm/Yb ion upconversion emission (blue and UV light). Thein vitroPDT was tested on 4T1 cells incubated with NaYF4:20%Yb,0.2%Tm@SiO2nanoparticles and irradiated with NIR light. After 24 h, cell viability decreased to below 10%, demonstrating very good treatment efficiency. High modification susceptibility of the SiO2shell allows for attachment of biological molecules (specific antibodies). In this work we attached the anti-human IgG antibody to silane-PEG-NHS-modified NaYF4:20%Yb,0.2%Tm@SiO2nanoparticles and a specifically marked membrane model by bio-conjugation. Thus, it was possible to perform a selective search (a high-quality optical method with a very low-level organic background) and eventually damage the targeted cancer cells. The study focuses on therapeutic properties of NaYF4:20%Yb,0.2%Tm@SiO2nanoparticles and demonstrates, upon biological functionalization, their potential for targeted therapy.

Multiparametric ultrasound examination for response assessment in breast cancer patients undergoing neoadjuvant therapy.

To investigate the performance of multiparametric ultrasound for the evaluation of treatment response in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). The IRB approved this prospective study. Breast cancer patients who were scheduled to undergo NAC were invited to participate in this study. Changes in tumour echogenicity, stiffness, maximum diameter, vascularity and integrated backscatter coefficient (IBC) were assessed prior to treatment and 7 days after four consecutive NAC cycles. Residual malignant cell (RMC) measurement at surgery was considered as standard of reference. RMC < 30% was considered a good response and > 70% a poor response. The correlation coefficients of these parameters were compared with RMC from post-operative histology. Linear Discriminant Analysis (LDA), cross-validation and Receiver Operating Characteristic curve (ROC) analysis were performed. Thirty patients (mean age 56.4 year) with 42 lesions were included. There was a significant correlation between RMC and echogenicity and tumour diameter after the 3rd course of NAC and average stiffness after the 2nd course. The correlation coefficient for IBC and echogenicity calculated after the first four doses of NAC were 0.27, 0.35, 0.41 and 0.30, respectively. Multivariate analysis of the echogenicity and stiffness after the third NAC revealed a sensitivity of 82%, specificity of 90%, PPV = 75%, NPV = 93%, accuracy = 88% and AUC of 0.88 for non-responding tumours (RMC > 70%). High tumour stiffness and persistent hypoechogenicity after the third NAC course allowed to accurately predict a group of non-responding tumours. A correlation between echogenicity and IBC was demonstrated as well.

Detection of Si doping in the AlN/GaN MQW using Super X - EDS measurements.

A multiple-quantum-well structure consisting of 40 periods of AlN/GaN:Si was investigated using a transmission electron microscope equipped with energy-dispersive X-ray spectroscopy. The thicknesses of the AlN barriers and the GaN quantum wells were 4 nm and 6 nm, respectively. The QW layers were doped with Si to a concentration of 1.3×1019cm-3 (0.012 % at). The procedure for quantifying such a doping level using AlN as a standard is presented. The EDS results (0.013 % at) are compared with secondary ion mass spectrometry measurements (0.05 % at).

Direct Measurement of Hyperfine Shifts and Radio Frequency Manipulation of Nuclear Spins in Individual CdTe/ZnTe Quantum Dots.

We achieve direct detection of electron hyperfine shifts in individual CdTe/ZnTe quantum dots. For the previously inaccessible regime of strong magnetic fields B_{z}≳0.1 T, we demonstrate robust polarization of a few-hundred-particle nuclear spin bath, with an optical initialization time of ∼1 ms and polarization lifetime exceeding ∼1 s. Nuclear magnetic resonance spectroscopy of individual dots reveals strong electron-nuclear interactions characterized by Knight fields |B_{e}|≳50 mT, an order of magnitude stronger than in III-V semiconductor quantum dots. Our studies confirm II-VI semiconductor quantum dots as a promising platform for hybrid electron-nuclear spin qubit registers, combining the excellent optical properties comparable to III-V dots and the dilute nuclear spin environment similar to group-IV semiconductors.

Mammalian cell defence mechanisms against the cytotoxicity of NaYF4:(Er,Yb,Gd) nanoparticles.

Water-soluble upconversion nanoparticles (UCNPs), based on polyvinylpyrrolidone (PVP)-coated NaYF4:Er3+,Yb3+,Gd3+, with various concentrations of Gd3+ ions and relatively high upconversion efficiencies, were synthesized. The internalization and cytotoxicity of the thus obtained UCNPs were evaluated in three cell lines (HeLa, HEK293 and astrocytes). No cytotoxicity was observed even at concentrations of UCNPs up to 50 µg ml-1. The fate of the UCNPs within the cells was studied by examining their upconversion emission spectra with confocal microscopy and confirming these observations with transmission electron microscopy. It was found that the cellular uptake of the UCNPs occurred primarily by clathrin-mediated endocytosis, whereas they were secreted from the cells via lysosomal exocytosis. The results of this study, focused on the mechanisms of the cellular uptake, localization and secretion of UCNPs, demonstrate, for the first time, the co-localization of UCNPs within discrete cell organelles.

Usefulness of combined BI-RADS analysis and Nakagami statistics of ultrasound echoes in the diagnosis of breast lesions.

AIM: To develop a method combining the statistics of the ultrasound backscatter and the Breast Imaging-Reporting and Data System (BI-RADS) classification to enhance the differentiation of breast tumours. MATERIALS AND METHODS: The Nakagami shape parameter m was used to characterise the scatter properties of breast tumours. Raw data from the radiofrequency (RF) echo-signal and B-mode images from 107 (32 malignant and 75 benign) lesions and their surrounding tissue were recorded. Three different characteristic values of the shape parameters of m (maximum [mLmax], minimum [mLmin] and average [mLavg]) and differences between m parameters (Δmmax, Δmmin, Δmavg) of the lesions and their surrounding tissues were assessed. A lesion with a BI-RADS score of 3 was considered benign, while a lesion with a score of 4 was considered malignant (a cut-off of BI-RADS 3/4 was set for all patients). RESULTS: The area under the receiver operating characteristic (ROC) curve (AUC) was equal to 0.966 for BI-RADS, with 100% sensitivity and 54.67% specificity. All malignant lesions were diagnosed correctly, whereas 34 benign lesions were biopsied unnecessarily. In assessing the Nakagami statistics, the sum of the sensitivity and specificity was the best for mLavg (62.5% and 93.33%, respectively). Only four of 20 lesions were found over the cut-off value in BI-RADS of 4a. When comparing the differences in m parameters, Δmavg had the highest sensitivity of 90% (only three of 32 lesions were false negative). These three lesions were classified as BI-RADS category 4c. The combined use of B-mode and mLmin parameter improve the AUC up to 0.978 (p=0.088), compared to BI-RADS alone. CONCLUSION: The combination of the parametric imaging and the BI-RADS assessment does not significantly improve the differentiation of breast lesions, but it has the potential to better identify the group of patients with mainly benign lesions that have a low level of suspicion for malignancy with a BI-RADS score of 4a.

Salvinorin A analogues PR-37 and PR-38 attenuate compound 48/80-induced itch responses in mice.

BACKGROUND AND PURPOSE: The opioid system plays a crucial role in several physiological processes in the CNS and in the periphery. It has also been shown that selective opioid receptor agonists exert potent inhibitory action on pruritus and pain. In this study we examined whether two analogues of Salvinorin A, PR-37 and PR-38, exhibit antipruritic properties in mice. EXPERIMENTAL APPROACH: To examine the antiscratch effect of PR-37 and PR-38 we used a mouse model of compound 48/80-induced pruritus. In order to elucidate the mechanism of action of tested compounds, specific antagonists of opioid and cannabinoid receptors were used. The effect of PR-37 on the CNS was assessed by measuring motor parameters and exploratory behaviours in mice. KEY RESULTS: PR-37 and PR-38, jnjected s.c., significantly reduced the number of compound 48/80-induced scratching behaviours in mice in a dose- and time-dependent manner. PR-38 was also active when orally administered. The antiscratch activity of PR-37 was blocked by the selective κ opioid receptor antagonist, nor-binaltorphimine, and that of PR-38 by the selective µ opioid receptor antagonist, ß-funaltrexamine. CONCLUSION AND IMPLICATIONS: In conclusion, a novel framework for the development of new antipruritic drugs derived from salvinorin A has been validated.

Novel ZnO/MgO/Fe2O3 composite optomagnetic nanoparticles.

A facile sol-gel synthesis of novel ZnO/MgO/Fe2O3 nanoparticles (NPs) is reported and their performance is compared to that of ZnO/MgO. Powder x-ray diffraction (XRD) patterns reveal the crystal structure of the prepared samples. The average particle size of the sample was found to be 4.8 nm. The optical properties were determined by UV-vis absorption and fluorescence measurements. The NPs are stable in biologically relevant solutions (phosphate buffered saline (PBS), 20 mM, pH = 7.0) contrary to ZnO/MgO NPs which degrade in the presence of inorganic phosphate. Superparamagnetic properties were determined with a superconducting quantum interference device (SQUID). Biocompatible and stable in PBS ZnO/MgO/Fe2O3 core/shell composite nanocrystals show luminescent and magnetic properties confined to a single NP at room temperature (19-24 ° C), which may render the material to be potentially useful for biomedical applications.

TEM determination of directions of (Ga,Mn)As nanowires grown by MBE on GaAs(001) substrates.

The structure of GaMnAs nanowires (NW) with nominal Mn concentration of up to 7 at% was investigated by transmission electron microscopy. The (Ga,Mn)As NW were grown on epiready GaAs(001) n-type wafers by molecular beam epitaxy. The crystal structure of the NW was determined to be zinc-blende. NW with Mn concentrations lower than 5 at% grow along the 111 direction. NW with higher Mn concentrations grow along the 110 direction and reveal a branching structure. The main nanowire and branches grow along the 110 directions belonging to only one {111} plane.

[Antisense oligonucleotides for therapy of cystic fibrosis. Inhibition of sodium absorption mediated by ENaC in nasal epithelial cells]. / Antisense-Oligonukleotide zur Therapie der Mukoviszidose. Inhibition der ENaC-vermittelten Natriumabsorption in humanen Nasenepithelzellen.

BACKGROUND: The genetic disease cystic fibrosis (CF) is characterised by reduced chloride secretion mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) and Na(+) hyperabsorption through amiloride-sensitive epithelial sodium channels (ENaC). Mutations in CFTR cause the accumulation of thick mucus and dysfunction of mucociliary clearance in the respiratory tract. MATERIAL AND METHODS: In this project it was investigated whether Na(+) hyperabsorption is inhibited by the use of antisense oligonucleotides (AON). For functional analyses monolayers of human non-CF and CF nasal epithelial cells were measured in modified Ussing chambers. To analyse the AON effects on the protein level Western blotting analyses were carried out. RESULTS: AON transfection significantly inhibits Na(+) absorption via ENaC in non-CF and CF cells. Furthermore, Western blot analyses demonstrate a suppression of the ENaC protein in AON transfected human non-CF cells. CONCLUSION: The inhibition of ENaC associated Na(+) absorption by specific AON could offer a new perspective for the regulation of the Na(+) hyperabsorption in CF patients.

Recession occurrence in patients treated with fixed appliances--preliminary report.

PURPOSE: The aim of the study was to evaluate the dependence of gingival recession, malocclusion and factors that may lead to recessions of the gingiva in patients applying for orthodontical treatment. MATERIAL AND METHODS: The study involved 52 randomly selected patients treated with fixed appliances due to occlusal irregularities and dental abnormalities. Data obtained from the examination and selected parameters from cephalometric analysis were placed in a chart including ANB skeletal class and Wits parameter, lower incisor position IMPA, dental abnormalities, extractions due to orthodontical indications and recession etiopathic factors. Statistical analysis of obtained data was conducted using variance analysis. Statistically significant were assumed those calculations for which value of significance level p < or = 0.05. RESULTS: Recession was observed in 18 patients of the 52 examined. Skeletal I class was found in 11 patients (61.12%) and in 8 cases Wits parameter corresponded with skeletal class III (44.4%). Among the patients examined normal incisor inclination was observed in 6 patients (33.33%), whereas 12 cases revealed inclination irregularities (66.66%). Clinical examination disclosed dental defects in 13 patients (72.22%) and in 12 cases recession etiopathic factors were recognized (66.66%). Statistically significant differences between periodontal biotype and gingival recession of 43, 31, 33 teeth were estimated. CONCLUSIONS: Anatomical factors, malocclusion and dental irregularities were fund to be the main cause of the single and/or multiple recessions. Patients applying for orthodontic treatment due to occlusal abnormalities should remain under particular control in case of symptoms suggesting the incidence of recession, particularly when recessions are already present.

The evaluation of parodontium in medical students of the Medical University of Bialystok according to CPITN index.

PURPOSE: The aim of the study was the evaluation of parodontium according to Community Peridental Index of Treatment Needs (CPITN) index in 455 students of The Medical and Dentistry Department of The Medical University of Bialystok. MATERIAL AND METHODS: After the examination, the students filled a survey according to their own project concerning hygienic habits as well as smoking, sweet intake. The results underwent statistical analysis. RESULTS: There were 1334 (48.86%) sextants observed with healthy parodontium in the studied population. Gingivorrhoea was stated in 440 sextants (16.12%), more often in men than in women. Calculus was reveled in 790 sextants (28.94%) of the population. The number of sextants with code 3 was 1.76%. Sextants with shallow pockets were more numerous in women (37 sextants) than in men (11 sextants). Advanced changes in parodontium (code 4) were observed in 9 sextants (0.33%). On the basis of the analysis of treatment needs in the group of 455 students, it can be stated that only 24.62% of the examined subjects did not need parodontium treatment. CONCLUSIONS: The diagnosis of parodontopathy and the factor that can have harmful influence on the parodontium tissues in young people is a superior criterion in the fight with irreversible parodontium changes in adults.

The oral cavity hygiene as the basic element of the gingival recession prophylaxis.

The purpose of the study was the evaluation of the dental plaque and the influence of determined hygienic factors on gingival recession occurrence in 455 students of The Medical University of Bialystok. All the subjects were examined in artificial light, with the use of the probe, mirror, and parodontometer. The distribution of stained dental deposits were estimated with the use of the plaque index according to Quigley and Hein. Moreover, the students were to fill a survey of their own project concerning hygienic habits. The results underwent statistical analysis. The dental plaque was not present in 71 people. Gingival recession was revealed in 134 out of 455 subjects. The majority of medical students brushed their teeth twice a day, using medium hard toothbrush or electric toothbrush with appropriate movements and medium strength while brushing. The frequency of brushing the teeth, hardness of the toothbrush, the use of electric toothbrush, the movements during brushing the teeth, the strength of brushing, the frequency of toothbrush change, the age, and sex have significant influence on the number of recession. The increase in the gingival recession in students is connected with: large pressure on the brush while toothbrushing, too frequent brushing and toothbrush change, the use of hard toothbrush and additional hygienic items, movements while brushing, the age (the number of recession elevates with the age), and sex (women showed more recession than men).

Allelic imbalance of BRCA1 transcript in the IVS20 12-bp insertion carrier.

One of the unclassified variants of the BRCA1 gene which has drawn considerable attention in recent years is the 12-bp insertion/duplication in intron 20. In this report, we show that a contribution from one chromosome cannot be detected in the BRCA1 transcript of the 12 bp insertion carrier. We also demonstrate here that the single transcript variant we observe by cDNA analysis originates from the same BRCA1 allele that harbours the 12-bp insertion. Hum Mutat 16:371, 2000.

High frequency of recurrent mutations in BRCA1 and BRCA2 genes in Polish families with breast and ovarian cancer.

Germ-line mutations in BRCA1 and BRCA2 genes result in a significantly increased risk of breast and ovarian cancer. Other genes involved in an increased predisposition to breast cancer include the TP53 gene, mutated in Li-Fraumeni syndrome. To estimate the frequency of germ-line mutations in these three genes in Upper Silesia, we have analyzed 47 breast/ovarian cancer families from that region. We found five different disease predisposing mutations in 17 (36%) families. Twelve families (25.5%) carried known BRCA1 mutations (5382insC and C61G), four families (8.5%) carried novel BRCA2 mutations (9631delC and 6886delGAAAA), and one family (2%) harbored novel mutation 1095del8 in the TP53 gene, which is the largest germline deletion in coding sequence of this gene identified thus far. The 5382insC mutation in BRCA1 was found in 11 families and the 9631delC mutation in BRCA2 occurred in three families. These two mutations taken together contribute to 82% of all mutations found in this study, and 30% of the families investigated harbor one of these mutations. The very high frequency of common mutations observed in these families can only be compared to that reported for Ashkenazi Jewish, Icelandic, and Russian high-risk families. This frequency, however, may not be representative for the entire Polish population. The observed distribution of mutations will favor routine pre-screening of predisposed families using a simple and cost-effective test.

Novel BRCA1 mutations and more frequent intron-20 alteration found among 236 women from Western Poland.

Three different novel BRCA1 mutations, five independent cases of the same 12 bp insertion-duplication in intron-20 and two novel rare BRCA1 sequence variants were identified among 122 Polish women with positive, in most cases moderate family history of breast and/or ovarian cancer, 80 controls and 34 unselected breast cancer tissue specimens. All mutations and variants were germline. The 4153 delA frameshift mutation, the Tyr105Cys missense mutation and two cases of the alteration in intron-20 were found in the group of healthy women with positive family history. Two other cases of the intronic insertion were found in unselected controls. Their carriers had no family history of breast or ovarian cancer but other cancers occurred in their families. The 1782 Trp/STOP nonsense mutation and one case of the insertion in intron-20 were first found in tissue specimens of breast cancer patient and breast/ovarian cancer patient, respectively. Their carriers also had no family history of breast or ovarian cancer. The distribution of the insertion in intron-20 in analysed groups and results of RT-PCR experiments suggest a less prominent role for this variant considered earlier a splicing mutation. This study shows also, that more population-oriented research is needed, involving women with less profound or even no family history of breast and ovarian cancer, to better understand the role and significance of different BRCA1 variants and mutations.

A comparison of infrared- and torch-soldering of Au-Pd and Co-Cr metal-ceramic alloys using a high-fusing solder.

PURPOSE: The purpose of this study was to compare the bond strengths and fracture modes of soldered joints formed by infrared and gas-oxygen torch heating of a high-fusing, gold-based solder in two metal-ceramic alloys. MATERIALS AND METHODS: Pairs of half-dumbbell-shaped specimens of either an Au-Pd or a Co-Cr alloy were positioned with a 0.25-mm gap and were joined using a high-fusing, gold-based solder by either gas-oxygen torch heating or infrared heating. The resulting specimens were subjected to a heat treatment that simulated ceramic firing. Each specimen was fractured in tension at a loading rate of 0.5 cm/min, and its bond strength was measured. The halves of the specimen were rejoined using the other heating method and were heat treated, and the specimen's bond strength was again measured. Fractured cross-sections were examined at a magnification of 40x to determine the following: the fracture mode (adhesive, cohesive, or mixed); the percentage of adhesive fracture; the presence or absence of voids, porosities, or flux inclusions; and the percentage of the cross-section that was discolored. RESULTS: Three-factor analyses of variance showed that neither the heating method, the particular specimen tested, nor the order of testing significantly affected the bond strength (P < .05). For each alloy, significantly fewer infrared-heated joints than torch-heated joints contained voids, porosities, or flux inclusions visible at 40x (chi 2 test, P < .05). All fractures were either entirely cohesive in the solder or mixed cohesive and adhesive. When infrared heating was used, entirely cohesive fractures occurred more frequently in the Au-Pd alloy specimens than in the Co-Cr alloy specimens (chi 2 test, P < .05). The coefficients of variation of the bond strengths for the infrared-heated joints were smaller than those for the torch-heated joints. CONCLUSIONS: Although the two heating methods produced solder joints that had strengths that were not significantly different, infrared-heated joints showed less scatter in bond strengths. It was suggested that, in the hands of most technicians, fewer infrared-heated joints would contain defects visible at a magnification of 40x. The presence of such defects may increase the probability of in vivo failure caused by cyclic stresses.

Faster and cheaper PCR on a standard thermocycler.

The PCR conditions have been optimized to make the process faster and more economical. When short DNA fragments are to be amplified, the time of denaturation, annealing and extension steps can be as short as 1 s each, and the yield of PCR product is still high, sufficient for many types of analysis. The PCR can be done even in a reaction volume as low as 1 microliter. The recommended volume, 2.5 microliters or 5 microliters, allows significant savings in the laboratory budget especially for laboratories which use PCR frequently and on a large scale.