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Antibodies against Lutheran blood group antigens have been observed during first-time pregnancy. Samples from a woman of African descent were tested in our immunohematology laboratory on several occasions since 2001. Her samples were phenotyped as Lu(a+b-), and anti-Lubwas suspected but not identified. She was asked to make autologous donations in preparation for her delivery, which she did. In 2010, two antibodies were identified: anti-Leaand -Lub. Six years later, a third investigation was requested. This time, an antibody directed at a high-prevalence Lutheran antigen was found in addition to the anti-Leaand -Lubpreviously observed. Her serum was compatible with three out of five Lu(a-b-) reagent red blood cells (RBCs). One of the incompatible Lu(a-b-) reagent RBCs was known to be In(Lu) (KLF1mutation). The genetic background of the other reagent RBC was unknown. The LUcDNA sequence analysis revealed the presence of the c.230G>A (Lua), c.679C>T (LU:–16), and a silent polymorphism c.1227G>T. Anti-Lu16 was highly suspected. This would be the fifth case of LU:–16 with antibodies reported, all within women of African heritage with the Lu(a+b-) phenotype. Hemolytic disease of the fetus and newborn was not noted in these cases. Immunohematology2017;33:110–113.

Objective:To measure body mass index (BMI) and ambulation changes for a morbidly obese, 47-year-old man with chronic motor-incomplete tetraplegia after gastric sleeve surgery.Design/Method:A morbidly obese man, BMI=44 kg m−2, with chronic C5 AIS D tetraplegia underwent elective gastric sleeve surgery. Assessment of BMI and function via the 6-minute walk test (6MWT), 10-meter walk test (10MWT) and ambulation parameters (CIR Systems/GAITRite, Franklin, NJ, USA) was performed preoperatively and at 12, 24, 36 and 52 weeks postoperatively, and additionally after 3 weeks of both a prescribed coached (3 × /week facility based) and a non-coached (3 × /week home based) walking program initiated at 52 weeks. A step activity monitor assessed daily ambulation preoperatively, prior to and during the third and sixth week of the walking program.Results:Results included a 34.3% peak BMI decrease at 52 weeks post surgery and a peak increase in 6MWT distance of 58% at 52 weeks post surgery, 10MWT preferred speed of 56% at 55 weeks and step activity monitor of 82% at 58 weeks post surgery. At 58 weeks, gait data demonstrated a decrease in double limb stance of 38% and decrease in base of support of 72%.Conclusion/Clinical Relevance:This empirical case assessment of BMI and functional mobility before and after gastric sleeve surgery may encourage further investigation into mobility and general health effects post gastric procedures for people with chronic motor-incomplete spinal cord injury.

In laparoscopic surgery, the surgeon receives limited haptic feedback and relies on visual feedback to judge the amount of force applied to tissues. It has been shown that friction forces inherent in the instrumentation increased the haptic perception threshold of naive subjects. A controlled experiment was conducted to examine the effects of experience on force perception threshold in a simulated tissue-probing task. Fourteen subjects participated in a mixed design experiment, with friction, vision, and tissue softness as independent within-subjects factors, experience as an independent between-subjects factor, and applied force and detection time as dependent measures. Higher thresholds and longer detection times were observed when friction was present. Experienced surgeons applied a greater force than novices, but were quicker to detect contact with tissue, suggesting that experience allowed surgeons to perform more efficiently while keeping within the limits of safety.

Current endoscopic instrumentation cannot replicate the haptic feedback available during open surgery. Distracting friction forces in the interface make it difficult for surgeons to detect and differentiate between small-scale surgical site forces. As a result, the visual channel is being used to process information that should be available through the haptic sense. An experiment was conducted to examine the effects of friction, when probing tissues of dissimilar compliance. Results showed that the presence of friction in the interface increased applied force by 45%, contact time by 40%, and errors by a factor of 2 (100%), while its absence increased human operator confidence by 15%. The effects of friction were generally more pronounced in conditions with impaired visual cues but were also very strong when vision was available. These results are applicable to the design of more effective instrumentation for endoscopic surgery as well as robotic surgery.

Current robotic systems for minimally invasive surgery do not have effective means of providing haptics to the surgeon. It was hypothesized that providing an analog for force feedback through the visual channel could benefit performance in the absence of actual force feedback. An experiment was conducted to examine performance in a simple line-drawing task in a simulator box using a conventional laparoscopic grasper with inherent force feedback and a robotic manipulator with no force feedback. The task was performed on a hard surface and a soft surface. Physical deformation on the soft surface provided additional visual cues regarding the forces applied during the task. Results showed better performance, in the absence of force feedback, when the visual analog of force was provided. Task completion time was best when physical force feedback was combined with augmented visual feedback. This research has implications for the implementation of haptics in robotic surgical systems.

ABSTRACTWe have investigated the secondary structure of peach latent mosaic viroid (PLMVd) in solution, and we present here the first description of the structure of a branched viroid in solution. Different PLMVd transcripts of plus polarity were produced by using the circularly permuted RNA method and the exploitation of RNA internal secondary structure to position the 5' and 3' termini and studied by nuclease mapping and binding shift assays using DNA and RNA oligonucleotides. We show that PLMVd folds into a complex, branched secondary structure. In general, this structure is similar to that reported previously, which was based on sequence comparison and computer modelling. The structural microheterogeneity is apparently limited to only some small domains. More importantly, this structure includes a novel pseudoknot that is conserved in all PLMVd isolates and seems to allow folding into a very compact form. This pseudoknot is also found in chrysanthemum chlorotic mottle viroid, suggesting that it is a unique feature of the viroid members of the PLMVd subgroup.

Our previous report on delta ribozyme cleavage using a trans -acting antigenomic delta ribozyme and a collection of short substrates showed that the middle nucleotides of the P1 stem, the substrate binding site, are essential for the cleavage activity. Here we have further investigated the effect of alterations in the P1 stem on the kinetic and thermodynamic parameters of delta ribozyme cleavage using various ribozyme variants carrying single base mutations at putative positions reported. The kinetic and thermodynamic values obtained in mutational studies of the two middle nucleotides of the P1 stem suggest that the binding and active sites of the delta ribozyme are uniquely formed. Firstly, the substrate and the ribozyme are engaged in the formation of a helix, known as the P1 stem, which may contain a weak hydrogen bond(s) or a bulge. Secondly, a tertiary interaction involving the base moieties in the middle of the P1 stem likely plays a role in defining the chemical environment. As a con-sequence, the active site might form simultaneously or subsequently to the binding site during later steps of the pathway.

ABSTRACTWe characterized the peach latent mosaic viroid (PLMVd) replication intermediates that accumulate in infected peach leaves and determined the tissue and subcellular localization of the RNA species. Using in situ hybridization, we showed that PLMVd strands of both plus and minus polarities concentrate in the cells forming the palisade parenchyma. At the cellular level, PLMVd was found to accumulate predominantly in chloroplasts. Northern blot analyses demonstrated that PLMVd replicates via a symmetric mode involving the accumulation of both circular and linear monomeric strands of both polarities. No multimeric conformer was detected, indicating that both strands self-cleave efficiently via their hammerhead sequences. Dot blot hybridizations revealed that PLMVd strands of both polarities accumulate equally but that the relative concentrations vary by more than 50-fold between peach cultivars. Taken together these results establish two hallmarks for the classification of viroids. Group A viroids (e.g., PLMVd), which possess hammerhead structures, replicate in the chloroplasts via the symmetric mode. By contrast, group B viroids, which share a conserved central region, replicate in the nucleus via an asymmetric mechanism. This is an important difference between self-cleaving and non-self-cleaving viroids, and the implications for the evolutionary origin and replication are discussed.

We report here the first demonstration of the cleavage of an mRNA in trans by delta ribozyme derived from the antigenomic version of the human hepatitis delta virus (HDV). We characterized potential delta ribozyme cleavage sites within HDV mRNA sequence (i.e. C/UGN6), using oligonucleotide binding shift assays and ribonuclease H hydrolysis. Ribozymes were synthesized based on the structural data and then tested for their ability to cleave the mRNA. Of the nine ribozymes examined, three specifically cleaved a derivative HDV mRNA. All three active ribozymes gave consistent indications that they cleaved single-stranded regions. Kinetic characterization of the ability of ribozymes to cleave both the full-length mRNA and either wild-type or mutant small model substrate suggests: (i) delta ribozyme has turnovers, that is to say, several mRNA molecules can be successively cleaved by one ribozyme molecule; and (ii) the substrate specificity of delta ribozyme cleavage is not restricted to C/UGN6. Specifically, substrates with a higher guanosine residue content upstream of the cleavage site (i.e. positions -4 to -2) were always cleaved more efficiently than wild-type substrate. This work shows that delta ribozyme constitutes a potential catalytic RNA for further gene-inactivation therapy.

This paper describes an optical correction system made from electrostatically actuated, surface machined micro-electromechanical (MEMS) mirrors. Such MEMS mirrors have applications in optical systems where they are used to correct wavefront aberrations and other image distortions. In our experiments, electrostatic actuators having a maximum surface-normal stroke of 2.5 μm control the individual orientations of each element in an array of 300-μm square mirror segments in the tip-tilt mode. Real time correction of random optical aberrations is demonstrated using a single mirror segment with four independently mounted corners and closed-loop feedback control.

This paper presents some of the methodological and conceptual issues in developing household and family projections. Alternative methods are briefly examined in light of some basic criteria and of Statistics Canada's experience in the application of the headship rate approach. This approach satisfies most of the basic criteria of a robust and practical method, and has the advantage of being able to use the latest population projections by age and sex as its base. It thus takes into consideration the changes in population structure which have a major effect on the number and composition of households and families. If the projections are prepared for a period of about 20 years, fertility assumptions will have no effect on the projected number of heads. The thrust of the projection work can therefore focus on the extrapolation of the series of headship rates. Other issues covered include conceptual changes in data series; selection of the explanatory variables and categories; and development of alternative assumptions.

The specificity of delta ribozyme cleavage was investigated using a trans-acting antigenomic delta ribozyme. Under single turnover conditions, the wild type ribozyme cleaved the 11-mer ribonucleotide substrate with a rate constant of 0.34 min-1, an apparent Km of 17.9 nM and an apparent second-order rate constant of 1.89 x 10(7) min-1 M-1. The substrate specificity of the delta ribozyme was thoroughly investigated using a collection of substrates that varied in either the length or the nucleotide sequence of their P1 stems. We observed that not only is the base pairing of the substrate and the ribozyme important to cleavage activity, but also both the identity and the combination of the nucleotide sequence in the substrates are essential for cleavage activity. We show that the nucleotides in the middle of the P1 stem are essential for substrate binding and subsequent steps in the cleavage pathway. The introduction of any mismatches at these positions resulted in a complete lack of cleavage by the wild type ribozyme. Our findings suggest that factors more complex than simple base pairing interactions, such as tertiary structure interactions, could play an important role in the substrate specificity of delta ribozyme cleavage.

No abstract available for this article.

BACKGROUND: A long time goal of the medical research community has been the identification of a reliable and valid marker for Crohn's disease. AIM: To identify differences in the genetic expression patterns of healthy and diseased tissues. METHOD: The RNA arbitrarily primed polymerase chain reaction (RAP-PCR) procedure was modified to improve its potential to identify clinical markers in heterogeneous RNA populations. RESULTS: With this procedure, a 1065 bp PCR product associated with the inflammation that occurs in Crohn's disease was identified, cloned and sequenced. Northern blot hybridisations showed that this novel sequence originates from a unique RNA species of 3.1 kb. Dot blot hybridisations clearly showed that this RNA species was specific to Crohn's disease. Moreover, its abundance seemed to correlate with the severity of inflammation. Finally, this RNA species was also detected in macroscopically normal areas from Crohn's disease specimens, suggesting that it appears either early during the disease or at least before severe manifestations. CONCLUSION: This finding of a 3.1 kb RNA species permits the discrimination of Crohn's disease manifestations. Although further clinical work is required, this transcript appears to have definite potential as a diagnostic marker.

Evidence from both structural and functional studies of the CD4 molecule suggests that several domains, including the transmembrane (TM) domain and the adjoining extracellular region (D4-TM linker), contribute to the post-gp12O-binding events leading to human immunodeficiency virus-mediated membrane fusion. To investigate such a role in syncytium formation and cell-free infectivity, we generated several deletion and substitution mutations in the TM and D4-TM linker regions of the CD4 molecule. We found that while the TM domain of CD4 was dispensable for cell-cell and virus-cell interactions, modifications in the D4-TM linker led to perturbations in both processes. Deletion of the five amino acid residues linking D4 to the TM domain resulted in a delayed and reduced capacity to form syncytia, whereas replacement of the residues with the heterologous sequence from the CD8 molecule restored the kinetic profile to wild-type CD4 levels. On the other hand, both mutants of the CD4 D4-TM linker demonstrated delayed cell-free human immunodeficiency virus type 1 infectivity profiles. The defective fusion capacity may be linked to structural perturbations identified with anti-CD4 monoclonal antibodies in the D1-D2 interface and D3 domain of the deletion mutant yet absent in D1 and D4. While all cells were found to bind comparable levels of gp120, both D4-TM linker mutants appeared to induce a decrease in the V3 loop exposure of bound gp120. This underexposure may explain the delays in cell-free infectivities observed for both of these mutants. Together, these findings confirm a role for regions of the CD4 molecule located outside D1 in post-gp120-binding events and suggest that the D4-TM interface contributes to the conformational changes that direct the fusion process.

This is an online database in order to facilitate research on viroid, viroid-like RNAs and human hepatitis delta virus by presenting a large number of sequences and related data in a comprehensive and user-friendly format (e.g., position of their self-catalytic domains, open reading frame, prediction of the most stable secondary structures, etc.). This online database is available on the WWW at http://www.callisto.si. usherb.ca/jpperra

The viroid and viroid-like RNA database is a compilation of all natural sequences published in journals or available from the GenBank and EMBL nucleotide sequence libraries. Several information regarding these RNA species such as the position of their self-catalytic domains and the open reading frame of the human hepatitits delta virus are provided. The database also includes a determination of the likely ancestral sequence of most species and a prediction of the most stable secondary structures of these sequences. This online database is available on the World Wide Web (http://www.callisto.si.usherb.ca/[symbol: see text]jpperra ). It should provide an excellent reference point for further phylogenetic and structure-function studies of these RNA species.