A Rare Cohort of Two Rhnull Individuals

Objective A 77 year old female was admitted with a subdural hematoma requiring 1 unit of apheresis platelets. She was a study subject in the 1960s and was found to be Rhnull, along with another individual who previously served as a directed donor for her. Methods Serologic testing performed by the immunohematology reference laboratory (IRL) confirmed that the patient was Rhnull and expressed anti-Rh29 antibodies. While searching for red blood cells (RBCs) for possible transfusion, it was discovered that the individual from the original study had recently donated an autologous unit. Results The IRL discovered that the donor’s antigen typing was r’r’. Testing had been performed using a molecular human erythrocyte antigen BeadChip (HBC). Due to the discrepancy between current and historical testing results, a donor segment was thawed and by tube testing confirmed to be Rhnull. A limitation of HBC is that many null phenotypes will be missed. Conclusion This case demonstrated that Rhnull evaluation of the donor required both serological and molecular methods.

Opto-Electrical Properties of Composite Materials Based on Two Benzotrithiophene Copolymers and Fullerene Derivatives

Two donor–acceptor copolymers based on a benzotrithiophene acceptor unit and an electron-donor segment of 4,8-didodecyloxybenzo[1,2-b;4,5-b′]dithiophene were investigated in the view of photovoltaic application. We provided the complete synthesis procedure supported with NMR spectra of the monomers obtained. The resulting copolymers, labeled P1 and P2 in this work, exhibit strong absorption in the visible region with a similar band gap of about 2.2 eV. In spite of the chemical similarity of both copolymers, the photovoltaic and carrier transport properties of the P1- and P2-based devices demonstrated a noticeable difference. Applying an optimization procedure, a power conversion efficiency of 4.6% has been achieved for the P2/PC71BM solar cells.

Characterization of Donor Genome Segments of BC2 and BC4 Way Rarem x Oryzica Llanos-5 Progenies Detected by SNP Markers

<p>Plant breeders<br />make a succession of backcrosses to introgress a character<br />from a donor parent into genomic background of a recurrent<br />parent. In several backcrossing, the proportion of a genome<br />tends to return almost fully to recurrent parent, except the<br />small donor genome segment harboring the character of<br />interest. The estimation of the proportion donor segment<br />through backcross generations has been analyzed<br />theoretically using complex mathematical simulations. In<br />this study, the proportion of donor introgression segments<br />were directly analyzed in advanced backcross populations,<br />BC2F7 and BC4F2. The analysis was done by using a set of<br />single nucleotide polymorphism (SNP) markers covering the<br />entire rice genome. Of the 384 SNP markers we found 124<br />markers which provide polymorphism between recurrent<br />parent, Way Rarem and Oryzica Llanos-5 as donor parent.<br />But only 55 SNP markers could detect Oryzica Llanos-5<br />alleles in BC2F7 and BC4F2 progenies. The result of this<br />analysis demonstrated that the average of donor segment<br />number was 14.5 in BC2F7 and 12.3 in BC4F2. It was reduced<br />15% from BC2F7 to BC4F2. The average of donor segment<br />length was 31.2 cM (centiMorgan) in BC2F7 and 8.79 cM in<br />BC4F2. It was decreased 72% during twice backcrossing. The<br />average of donor genome size was 343.95 cM in BC2F7 and<br />71.35 cM in BC4F2, which means there was 79% decrease<br />from BC2F7 to BC4F2. These results offered a simple method<br />to describe the proportion of target genome segment from<br />donor parent. It was required as one of the main selection<br />criteria in backcross programs.</p>

EFFECT OF THIOPHENE IN BITHIAZOLE-BRIDGED SENSITIZERS ON THE PERFORMANCE OF DYE-SENSITIZED SOLAR CELLS

In this paper, we have designed and synthesized four bithiazole-bridged sensitizers (BT-T2, TBT-T2, BT-T3 and TBT-T3) with triphenylamine and indoline as the donor segment and applied them to dye-sensitized solar cells (DSSCs). For triphenylamine-based sensitizers as BT-T2 and TBT-T2, adding one thiophene unit between triphenylamine donor and bithiazole moiety not only led to bathochromic shift of the maximum absorption and increase of molar extinction coefficient, but also enhanced the photovoltaic conversion efficiency from 7.12% of BT-T2 to 7.51% of TBT-T2. But for indoline-based sensitizers as BT-T3 and TBT-T3, adding one thiophene unit between indoline donor and bithiazole moiety resulted in hypochromatic shift instead of bathochromic shift. We employed the density functional theory (DFT) calculations to further investigate the influence of the thiophene unit on their optical and electronic properties and photovoltaic performance of corresponding DSSC devices. Given the results, a reasonable explanation is the introduction of thiophene unit suppressed the intramolecular charge transfer and charge separation in the conjugation system of indoline-based sensitizer, which led to the hypochromatic shift of the maximum absorption wavelength and finally the low J sc . Since the J sc dropped sharply from 15.26 mAcm-2 to 4.52 mAcm-2, the photovoltaic conversion efficiency decreased dramatically from 7.86% to 1.93%.

Size of Donor Chromosome Segments Around Introgressed Loci and Reduction of Linkage Drag in Marker-Assisted Backcross Programs

This article investigates the efficiency of marker-assisted selection in reducing the length of the donor chromosome segment retained around a locus held heterozygous by backcrossing. First, the efficiency of marker-assisted selection is evaluated from the length of the donor segment in backcrossed individuals that are (double) recombinants for two markers flanking the introgressed gene on each side. Analytical expressions for the probability density function, the mean, and the variance of this length are given for any number of backcross generations, as well as numerical applications. For a given marker distance, the number of backcross generations performed has little impact on the reduction of donor segment length, except for distant markers. In practical situations, the most important parameter is the distance between the introgressed gene and the flanking markers, which should be chosen to be as closely linked as possible to the introgressed gene. Second, the minimal population sizes required to obtain double recombinants for such closely linked markers are computed and optimized in the context of a multigeneration backcross program. The results indicate that it is generally more profitable to allow for three or more successive backcross generations rather than to favor recombinations in early generations.

TEA inhibits ACh-induced EDRF release: endothelial Ca(2+)-dependent K+ channels contribute to vascular tone

The effects of K(+)-channel blockers on the acetylcholine (ACh)-induced relaxation of vascular smooth muscle, intracellular free Ca2+ concentration ([Ca2+]i) elevation, and ACh-evoked outward K+ current of endothelial cells of rabbit aorta were studied using bioassay, spectrofluorimetry, and patch-clamp techniques, respectively. In bioassay experiments, ACh caused relaxation of endothelium-denuded aortic rings in a concentration-dependent manner when perfused through an endothelium-intact donor segment of aorta but not when perfused directly onto the recipient aortic ring. ACh-induced relaxation was inhibited by perfusion of tetraethylammonium ions (TEA; 5 mM) through the donor but not by perfusion directly onto the recipient segment. Glibenclamide had no effect on ACh-induced relaxation of the bioassay ring in either situation. ACh increased [Ca2+]i at the endothelial surface of aortic strips but not at the adventitial surface. TEA inhibited ACh-induced [Ca2+]i elevation, whereas glibenclamide had no effect. In patch-clamp experiments with freshly isolated endothelial cells, ACh evoked a biphasic outward current which was completely abolished by TEA (3 mM). It is concluded that Ca(2+)-dependent K+ channels are important for increasing [Ca2+]i during agonist stimulation and consequently for the synthesis/release of endothelium-derived relaxing factors (EDRFs). Furthermore, endothelial ATP-sensitive K+ channels do not contribute to ACh-induced relaxation or evoke an increase in endothelial [Ca2+]i of rabbit thoracic aorta.

Bioassay of endothelium-derived relaxing factor in diabetic rat aorta

The bioassay technique was utilized to quantitate endothelium-derived relaxing factor (EDRF) released from perfused donor segments of control and diabetic rat aorta. In the presence of indomethacin, perfusates of donor segments with endothelium were allowed to superfuse recipient detector rings of normal rat aorta without endothelium. Under basal conditions, relaxations of the bioassay rings to perfusates of control and diabetic donor segments were similar. Perfusion of donor segments with acetylcholine produced relaxation of bioassay rings, which was decreased from endothelial perfusion of diabetic donor segments. These relaxations were inhibited by addition of methylene blue to the detector ring or by perfusion of donor segments with nitro-L-arginine. Infusion of superoxide dismutase (SOD) at a site proximal to the donor segment normalized relaxations induced by acetylcholine addition to diabetic donors. In contrast, infusion of SOD distal to the donor had no effect on acetylcholine-stimulated relaxations of detector rings from control donors while attenuating, paradoxically, the relaxations of detector rings from diabetic donors. These results suggest that diabetic rat aortas release similar levels of EDRF in response to acetylcholine, but the action of EDRF arising from diabetic donors is attenuated by enhanced release of oxygen-derived free radicals, which limits EDRF-mediated relaxation of vascular smooth muscle.

Converting-enzyme inhibitors potentiate bradykinin-induced relaxation in vitro

Experiments were designed to study the effects of converting-enzyme inhibitors (captopril and S 10211) on the endothelium-dependent relaxation to bradykinin in isolated porcine arteries. Rings of femoral arteries with and without endothelium were suspended in organ chambers to record isometric tension. Rings of coronary arteries without endothelium were used as bioassay tissue to record release of endothelium-derived relaxing factor (EDRF) from perfused femoral arteries. In organ chambers, bradykinin induced endothelium-dependent relaxation and, inconsistently, endothelium-independent contraction of the femoral artery rings. The relaxation is mediated by endothelial B2 bradykinin receptors, the contraction through B1 bradykinin receptors. Converting-enzyme inhibitors induced a weak potentiation of the contractile response and weak or no potentiation of the endothelium-dependent relaxation. In the presence of indomethacin, the response to bradykinin was not modified and no potentiation from the inhibitor could be observed. Blockade of the contractile response with a B1 bradykinin antagonist did not unmask a potentiation of the bradykinin endothelium-dependent relaxation by the converting-enzyme inhibitors. However, in the presence of B2 bradykinin antagonist, when high concentrations of bradykinin are required to induce relaxation, converting-enzyme inhibitors potentiated the effects of bradykinin. In contrast, in bioassay conditions with a perfused vascular segment, converting-enzyme inhibitors selectively enhanced the release of EDRF by bradykinin. This effect is observed in the bioassay tissue and in the donor segment. These results suggest that converting enzyme is indeed a powerful modulator of bradykinin action and that other enzymatic pathways of bradykinin metabolism present in the vascular wall could mask its action.

Endothelium-dependent pressure-induced contraction of isolated canine carotid arteries

Experiments were conducted in a bioassay system, where a canine coronary artery ring without endothelium (bioassay tissue) was superfused by the effluent from a perfused canine carotid artery segment with endothelium (donor segment). A rapid increase in transmural pressure (from near 0 to 32-38 mmHg) triggered active contraction of the donor segment and simultaneously of the bioassay tissue. These contractions were prevented by removal of the endothelium from the donor segment but not by treatment of the segment with indomethacin. Exposure to elevated pressure depressed basal, acetylcholine-, and flow-induced release of endothelium-derived relaxing factor(s). Methylene blue prevented the pressure-induced contraction of the bioassay ring. These data show that pressure-induced contraction of isolated carotid arteries is endothelium dependent and is mediated by the depression of the synthesis and/or release of endothelium-derived relaxing factor(s).

Characterization of segmental collateral blood flow in the small intestine

Collateral blood flow and the pressures and resistances determining that flow were measured between two adjacent segments of canine jejunum following acute occlusion of the arterial branch perfusing one of the segments (the “recipient” segment). Collateral flow was approximately 55% of control flow in the recipient segment. This flow was provided by an equal increment in arterial flow to the nonischemic (“donor”) segment, such that pressures, resistances, and flows in the donor segment were not affected. Virtually all of the total collateral flow was derived from precapillary channels and was therefore available to the capillary bed of the recipient segment. Collateral flow was adequate to maintain the recipient segment in a nonischemic state, as indicated by the absence of a reactive hyperemia following release of the arterial occlusion. Selective occlusions of intramural or extramural collateral channels indicate that about two-thirds of the total collateral flow is derived from the extramural (marginal) vessels, while the remainder is supplied by intramural collaterals. For the most part collateral flow between adjacent segments is determined simply by the pressure gradient between connecting collateral channels.