Magnetic resonance imaging of brain abnormalities in patients with the Nijmegen breakage syndrome

The results of brain MRI are presented in 22 patients with documented Nijmegen breakage syndrome (NBS), aged from 1 and 9/12 to 20 years. T1-, PD or FLAIR and T2-weighted SE/TSE images in three planes were obtained. Twenty-one patients showed microcephaly. Decreased size of frontal lobes and narrow frontal horns of the lateral ventricles was observed in all cases. In 6 patients agenesis of the posterior part of the corpus callosum was found as well as colpocephaly and temporal horn dilatation. In 2 patients callosal hypoplasia was accompanied by other anomalies: abnormal cerebrospinal fluid spaces. Sinusitis was present in all patients as a result of primary immunodeficiency. As in ataxia teleangiectasia and other breakage syndromes, NBS patients show inherited malignancy susceptibility and hypersensitivity to X and gamma radiation. Because of that computed tomography is contraindicated in these patients and MRI should be the method of choice in diagnostic imaging.     

Effects of active recovery on power output during repeated maximal sprint cycling

The effects of active recovery on metabolic and cardiorespiratory responses and power output were examined during repeated sprints. Male subjects (n = 13) performed two maximal 30-s cycle ergometer sprints, 4 min apart, on two separate occasions with either an active [cycling at 40 (1)% of maximal oxygen uptake; mean (SEM)] or passive recovery. Active recovery resulted in a significantly higher mean power output ( ) during sprint 2, compared with passive recovery [ ] 603 (17) W and 589 (15) W, P < 0.05]. This improvement was totally attributed to a 3.1 (1.0)% higher power generation during the initial 10 s of sprint 2 following the active recovery (P < 0.05), since power output during the last 20 s sprint 2 was the same after both recoveries. Despite the higher power output during sprint 2 after active recovery, no differences were observed between conditions in venous blood lactate and pH, but peak plasma ammonia was significantly higher in the active recovery condition [205 (23) vs 170 (20) μmol · 1⁻¹;P < 0.05]. No differences were found between active and passive recovery in terms of changes in plasma volume or arterial blood pressure throughout the test. However, heart rate between the two 30-s sprints and oxygen uptake during the second sprint were higher for the active compared with passive recovery [148 (3) vs 130 (4) beats · min⁻¹;P < 0.01) and 3.3 (0.1) vs 2.8 (0.1) 1 · min⁻¹;P < 0.01]. These data suggest that recovery of power output during repeated sprint exercise is enhanced when low-intensity exercise is performed between sprints. The beneficial effects of an active recovery are possibly mediated by an increased blood flow to the previously exercised muscle.     

The measurement of the tacticity of poly(vinyl chloride) by 13C nuclear magnetic resonance spectroscopy

Fourier transform ¹H-decoupled ¹³C NMR spectra were obtained on seven poly(vinyl chloride), (PVC), samples in solution in o-dichlorobenzene. Four of the polymers were of the commercial type and the others were prepared by suspension polymerisation at +90°C, +5°C, and -30°C. Measurements of the spectra were used to assess the precision and accuracy with which information about the tacticity of PVC can be obtained from such spectra. The results show that the well-resolved α-carbon triad and β-carbon tetrad spectra obtained may be reliably analysed to give values of the probability of syndiotactic placement with a precision of about 0,005 for measurements on a single run on a single sample. The simplest and probably the most reliable method of measuring the areas under the peaks which correspond to specific triads ot tetrads is to use the spectrometer integrator, although results of slightly lower precision may be obtained by the use of a curve resolver. Consideration of possible systematic errors due to different T₁ relaxation times, unequal nuclear Overhauser enhancement (NOE) factors, and incomplete dissolution of the polymer has shown that the only one of these which is possibly significant is that due to NOE, which is almost certainly less than 0,008, so that the absolute accuracies of the P_r values should be better than that. A more detailed study of the data shows that the polymers made at 5°C and -30°C are almost certainly non-Bernoullian and that firstoder Markov statistics can adequately describe the observed departures from Bernoullian statistics. These departures may have significant consequences for the physical properties of the polymers.     

Induction of chromosmal aberrations in the syrian hamster by insecticides tested in vivo

The insecticides demeton, dimetoat, dichlorovos, endosulfan, trichlorofon, carbaryl, lindane, methoxychlor, propoxur and malathion were examined for their ability to induce chromosomal aberrations in the bone marrow cells of the Syrian hamster (Mesocricetus auratus) treated in vivo. Mutagenicity of commercial preparations was examined at four doses: LD₅₀; 1/2, 1/5 and 1/10 LD₅₀. The positive control was an IP injection of cyclophosphamide to hamsters at a dose of 40 mg/kg body wt. Demeton, dichlorovos and endosulfan gave positive results. Malathion, dimethoate and the mixture of methoxychlor and propoxur were weakly clastogenic; at some doses these compounds induced statistically significant increases in the number of aberrations. Trichlorfon and the mixture of carbaryl and lindane were negative in this test.This work was supported by the Polish Academy of Sciences within the projet 09.7.3.4.3     

Hypertension two years after renal transplantation: causes and consequences

The incidence of hypertension 2 years after renal transplantation and the possible causes of hypertension were studied retrospectively. A group of 93 patients treated with cyclosporin (CyA), azathioprine (Aza), and/or prednisolone (Pred) were compared to a group of 31 patients treated with Aza and Pred. There were more patients with hypertension in the CyA group (73%) than in the Aza group (58%). Hypertension before transplantation predisposed to hypertension after transplantation. After transplantation, hypertension was most common among patients with polycystic kidney disease (46%), chronic glomerulonephritis (67%), and diabetes (71%). The accumulated immunosuppressive medication (CyA/Pred) did not affect the occurrence of hypertension. Hypertensive patients had significantly poorer graft function than did normotensive patients (serum creatinine level 229 mol/l vs 162 mol/l, P<0.01). The 10-year graft survival was markedly impaired in the group with hypertension (42% vs 65% for normotensives, P<0.05). The 10-year patient survival was 59% vs 79% (P=NS). The study further confirms the frequent finding that hypertension has a negative effect on graft and patient survival rates.     

Effects of lead,copper, and zinc on the rat's lactate dehydrogenase in vivo and in vitro

Following subacute intoxication of rats with Pb-, Cu-, and Zn-salts (separately or in mixture) for 5 weeks, the chelating agent D-penicillamine was administered for 3 weeks. In the course of the 3-month experiment, lactate dehydrogenase (LDH) was estimated in serum and in cytoplasmic fraction of the kidney. Pb²⁺ treatment resulted in an increase of LDH activity, Cu²⁺ in a slight decrease, whereas Zn²⁺ had no effect, respectively. Mixture of these metals caused a significant rise in the enzymatic activity. Seven weeks after the stoppage of the administration of toxic substances, altered LDH activity, both in serum and in kidney returned to normal. D-penicillamine treatment was found to accelerate a restoration of the enzyme activity.In the experiments in vitro, Cu²⁺ inhibited significantly the kidney LDH activity, Pb²⁺ and Zn²⁺ being 100- and 400-times less efficient, respectively. Cu²⁺ inhibition was reversed by D-penicillamine, whereas inhibition of LDH by Zn²⁺ or Pb²⁺ was irreversible.     

Comparative analysis of minimal residual disease detection using four-color flow cytometry, consensus IgH-PCR, and quantitative IgH PCR in CLL after allogeneic and autologous stem cell transplantation.

The clinically most suitable method for minimal residual disease (MRD) detection in chronic lymphocytic leukemia is still controversial. We prospectively compared MRD assessment in 158 blood samples of 74 patients with CLL after stem cell transplantation (SCT) using four-color flow cytometry (MRD flow) in parallel with consensus IgH-PCR and ASO IgH real-time PCR (ASO IgH RQ-PCR). In 25 out of 106 samples (23.6%) with a polyclonal consensus IgH-PCR pattern, MRD flow still detected CLL cells, proving higher sensitivity of flow cytometry over PCR-genescanning with consensus IgH-primers. Of 92 samples, 14 (15.2%) analyzed in parallel by MRD flow and by ASO IgH RQ-PCR were negative by our flow cytometric assay but positive by PCR, thus demonstrating superior sensitivity of RQ-PCR with ASO primers. Quantitative MRD levels measured by both methods correlated well (r=0.93). MRD detection by flow and ASO IgH RQ-PCR were equally suitable to monitor MRD kinetics after allogeneic SCT, but the PCR method detected impending relapses after autologous SCT earlier. An analysis of factors that influence sensitivity and specificity of flow cytometry for MRD detection allowed to devise further improvements of this technique.     

An Investigation of the Thermal Transitions and Physical Properties of Semiconducting PDPP4T:PDBPyBT Blend Films

This work focuses on the study of thermal and physical properties of thin polymer films based on mixtures of semiconductor polymers. The materials selected for research were poly [2,5-bis(2-octyldodecyl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2″;5″,2′′′-quater-thiophen-5,5′′′-diyl)]—PDPP4T, a p-type semiconducting polymer, and poly(2,5-bis(2-octyldodecyl)-3,6-di(pyridin-2-yl)-pyrrolo [3,4-c]pyrrole-1,4(2H,5H)-dione-alt-2,2′-bithiophene)—PDBPyBT, a high-mobility n-type polymer. The article describes the influence of the mutual participation of materials on the structure, physical properties and thermal transitions of PDPP4T:PDBPyBT blends. Here, for the first time, we demonstrate the phase diagram for PDPP4T:PDBPyBT blend films, constructed on the basis of variable-temperature spectroscopic ellipsometry and differential scanning calorimetry. Both techniques are complementary to each other, and the obtained results overlap to a large extent. Our research shows that these polymers can be mixed in various proportions to form single-phase mixtures with several thermal transitions, three of which with the lowest characteristic temperatures can be identified as glass transitions. In addition, the RMS roughness value of the PDPP4T:PDBPyBT blended films was lower than that of the pure materials.