Dynamic nuclear polarization at very low magnetic fields

Non-mosaic Klinefelter patients are generally azoospermic due to primary testicular failure. Nevertheless, in some cases, testicular spermatozoa may be recovered and utilized to fertilize oocytes via intracytoplasmic sperm injection (ICSI). As the risk for an increased number of gonosomes in these spermatozoa is unclear, preimplantation genetic diagnosis (PGD) may be attempted in the resulting embryos. In the present study, we report our experience with the combined approach of sperm retrieval by testicular fine needle aspiration (FNA), ICSI and PGD in seven consecutive non-mosaic Klinefelter individuals. In four patients, between one and five spermatozoa were retrieved in five out of nine consecutive attempts. In a fifth patient, only 10 round spermatids could be isolated. Mature spermatozoa were injected into a total of 16 metaphase-II oocytes, of which 11 (69%) remained intact. Two distinct pronuclei (2PN) were observed in four oocytes (36%) while a single pronucleus (1PN) was documented in two oocytes. Five cleavage stage embryos developed from the oocytes of two couples. Upon the request of one couple, their three embryos (two derived from 1PN oocytes) were transferred without PGD but pregnancy was not achieved. PGD by fluorescence in-situ hybridization (FISH) was performed in the two embryos of the other couple which were derived from normal fertilization. PGD results of one embryo were 18,18,X,X,Y, the embryo was not transferred and FISH analysis of the remaining blastomeres identified variable chromosome numbers in the nuclei. The second embryo was diagnosed as normal and was transferred, resulting in a successful pregnancy and birth. In conclusion, the results of this report indicate that a pregnancy and birth may be attained in azoospermic non-mosaic Klinefelter individuals by testicular FNA combined with ICSI. Due to the unknown risk of gonosomes aneuploidy in embryos from Klinefelter patients, PGD or prenatal diagnosis should be recommended.     

Evaluation of preclinical signs due to exposure of workers to static magnetic fields

We report the use of granulocyte colony-stimulating factor (G-CSF) in a renal transplant recipient in whom neutropenia developed following a presumed viral infection. G-CSF was successful in producing a rise in neutrophil count which coincided with a resolution of fever; there was no adverse effect on renal function. This is the first use of G-CSF in a paediatric renal transplant recipient, and its use should be considered for the immunosuppressed child with persistent neutropenia.     

Thermoelectric and electrical characteristics of SmS ceramic samples after exposure to a pulsed magnetic field

Samarium monosulfide (SmS) is a promising material for creating thermoelectric generators (TEG), gas sensors and strain gauges. Despite the high values of the generated thermo electromotive force (TEMF) (α ≈ 170–350 μV/K), methods for increasing the efficiency of TEGs based on SmS are of considerable interest. One of these methods can be short-term effects of magnetic fields, including pulsed ones, on these materials. The action of a pulsed magnetic field (PMF) leading to an increase in TEMF (U_T) of SmS ceramic samples is found. Samples that are not subjected to high frequency currents (HFC) annealing show an increase in U_T of 44.54%–62.18% (from 11.9 to 17.2–19.3 mV). The conductivity (σ) of the samples is ～ 22 Ω^?1/cm and is insensitive to short-term exposure to a PMF. Samples that undergo HFC annealing show an increase in U_T of 23.47%–41.31% (from 21.3 to 26.3–30.1 mV) after exposure to a PMF. The conductivity of the samples is ～ 15 Ω^?1/cm and after a short exposure to the PMF is changing non-monotonically, with an increase in the overall instability. The difference in the values of U_T and σ can be explained by presence of an ordered grain structure and a significant amount of the Sm₂O₂S phase in the samples subjected to HFC annealing. Possible mechanisms of the observed changes are discussed.