Quantification of mechanical ventricular dyssynchrony: direct comparison of velocity-encoded and cine magnetic resonance imaging.

PURPOSE: The preoperative assessment of mechanical dyssynchrony can help to improve patient selection in candidates for cardiac resynchronization therapy (CRT). The present study compared the performance of velocity-encoded (VENC) MRI to cine-magnetic resonance imaging (MRI) for quantifying mechanical ventricular dyssynchrony. MATERIALS AND METHODS: VENC-MRI and cine-MRI were performed in 20 patients with heart failure NYHA class III and reduced ejection fraction (median: 24 %, interquartile range: 18 - 28 %) before CRT device implantation. The interventricular mechanical delay (IVMD) was assessed by VENC-MRI as the temporal difference between the onset of aortic and pulmonary flow. Intraventricular dyssynchrony was quantified by cine-MRI, using the standard deviation of time to maximal wall thickening in sixteen left ventricular segments (SDt-16). The response to CRT was assessed in a six-month follow-up. RESULTS: 14 patients (70 %) clinically responded to CRT. A similar accuracy was found to predict the response to CRT by measurements of the IVMD and SDt-16 (75 vs. 70 %; p = ns). The time needed for data analysis was significantly shorter for the IVMD at 1.69 min (interquartile range: 1.66 - 1.88 min) compared to 9.63 min (interquartile range: 8.92 - 11.63 min) for the SDt-16 (p < 0.0001). CONCLUSION: Measurements of the IVMD by VENC-MRI and the SDt-16 by cine-MRI provide a similar accuracy to identify clinical responders to CRT. However, data analysis of the IVMD is significantly less time-consuming compared to data analysis of the SDt-16.

Self-assembled growth of catalyst-free GaN wires by metal-organic vapour phase epitaxy.

A catalyst-free method for growing self-assembled GaN wires on c-plane sapphire substrates by metal-organic vapour phase epitaxy is developed. This approach, based on in situ deposition of a thin SiN(x) layer (approximately 2 nm), enables epitaxial growth of c-oriented wires with 200-1500 nm diameters and a large length/diameter ratio (>100) on c-plane sapphire substrate. Detailed study of the growth mechanisms shows that a combination of key parameters is necessary to obtain vertical growth. In particular, the duration of the SiN(x) deposition prior to the wire growth is critical for controlling the epitaxy with the substrate. The GaN seed nucleation time determines the mean size diameter and structural quality, and a high Si-dopant concentration promotes vertical growth. Such GaN wires exhibit UV-light emission centred at approximately 350 nm and a weak yellow band (approximately 550 nm) at low temperature.

Delayed-enhancement magnetic resonance imaging in patients with clinically suspected stress cardiomyopathy (Tako-tsubo).

PURPOSE: To compare the ability of delayed-enhancement magnetic resonance imaging (DE-MRI) and other MRI and clinical parameters to identify diseases mimicking stress cardiomyopathy (SCM). MATERIALS AND METHODS: The study included 14 consecutive patients fulfilling the American Heart Association (AHA) criteria for SCM with acute left ventricular dysfunction in the absence of coronary artery disease, triggered by psychological stress. The MRI protocol consisted of cine, T 2-weighted, first-pass-perfusion (FPP) and DE-MRI. RESULTS: Six patients with DE were classified as mimicking SCM (non-SCM) and 8 patients without DE as SCM. FPP defects were found in 4 patients with non-SCM and in none with SCM (p < 0.05). Myocardial edema was found in 5 patients with non-SCM and in 2 patients with SCM (p = ns). No significant differences in clinical findings such as ECG, cardiac markers and echocardiographic recovery of left ventricular function were found between patients with non-SCM and SCM. CONCLUSION: Non-SCM defined by DE-MRI is a frequent finding in patients fulfilling the AHA criteria for SCM. Clinical findings seem to be of limited value to differentiate between non-SCM and SCM.

[Quality of life following percutaneous coronary interventions in octogenarians]. / Perkutane Koronarinterventionen verbessern die Lebensqualität von Patienten nach dem 80. Lebensjahr.

BACKGROUND: Percutaneous coronary interventions (PCI) are increasingly performed in elderly patients. However, it is not known whether PCI leads to symptomatic relief comparable to that in younger patients. PATIENTS AND METHODS: 55 Patients aged 80 years or above with stable angina (82 +/- 2 years, 33 males, 22 females) were prospectively compared with younger patients (62 +/- 8 years) regarding their quality of life following PCI. For psychometric evaluation, the German version of the SF-36 Health Survey was used. RESULTS: Prior to angioplasty, there was significant physical pain, a perception of reduced general health and a significant limitation of physical activity in both groups. The number of diseased vessels was 2.7 +/- 0.6 in octogenarian patients vs. 2.6 +/- 0.7 in control patients; interventions were performed in 1.1 +/- 0.3 vs. 1.0 +/- 0.2 vessels and in 1.3 +/- 0.7 vs. 1.3 +/- 0.5 lesions. Frequency of stent implantation was 0.9 +/- 0.3 per lesion in both groups. Success rates were comparable in both groups (94 % vs. 97 %), as well as complication rates In both groups 6 months after angioplasty, bodily pain had decreased, the perception of general health and the ability to fulfill physical role expectations had improved. The effects on bodily pain and on the ability to fulfill physical role expectations were more pronounced in octogenarian patients. CONCLUSIONS: Our study shows that PCI improves quality of life in octogenarian patients with stable angina without excessive risk. The benefits of PCI were, in some aspects, even more pronounced than in younger patients.

Seventeen novel HLA-A alleles.

This paper describes 17 novel HLA-A alleles: A*0244, A*0251, A*0254, A*0309, A*1111, A*2432, A*2434, A*2504, A*2618, A*2905, A*2906, A*3106, A*3107, A*3207, A*6820, A*7407, and A*7408. Most substitutions are found in other alleles.

Twenty-five novel HLA-B alleles.

Twenty-five novel HLA-B alleles are described in this paper: B*0729, B*1309, B*1814, B*1815, B*2724, B*2725, B*3539, B*3926, B*4037, B*4040, B*4042, B*4043, B*4044, B*4204, B*440203, B*4428, B*4429, B*4430, B*4505, B*5308, B*5309, B*5510, B*5511, B*570102, and B*5709. Most of the variants are single nucleotide substitutions. Two involve variants at the Bw4/Bw6 epitope. Two alleles carry substitutions of conserved amino acids.

Novel HLA-A locus alleles including A*01012, A*0306, A*0308, A*2616, A*2617, A*3009, A*3206, A*3403, A*3602 and A*6604.

This paper describes 10 novel HLA-A alleles that have been characterized by DNA sequencing. Seven alleles, A*0308, A*2616, A*3009, A*3206, A*3403, A*3602 and A*6604 carry motifs observed in other HLA-A alleles, suggesting that gene conversion has created this diversity. The remaining three alleles, A*01012, A*0306 and A*2617, contain polymorphisms not previously found in any "classical" class I allele. All alleles were identified due to unexpected probe hybridization patterns during routine SSOP typing. Exons 2 and 3 of each allele were subsequently characterized by DNA sequencing.

Eight new HLA-A alleles associated with antigens in the A2 CREG.

This report describes eight novel HLA-A alleles. Seven of these new alleles contain substitutions previously reported in other HLA-A alleles, suggesting an origin resulting from a gene conversion mechanism. Of these seven, A*2431 contains a substitution previously associated with a larger polymorphic motif. A*0247 contains a substitution at a previously polymorphic position, but encodes an amino acid change previously unreported in any HLA-A, -B or -C alleles.

Novel HLA-B alleles formed by an inter-locus recombination with HLA-C, HLA-B*0713 and B*6702.

This paper describes two novel HLA-B locus alleles. B*0713 appears to have resulted from an interlocus recombinational event which inserted a sequence from an HLA-C allele into B*0702. This event altered a significant portion of the alpha-1 domain alpha helix. B*6702 shares much of its exon 2 sequence with B*0713 but is identical in exon 3 to several HLA-B locus alleles including B*67012.

Twelve novel HLA-B*15 alleles carrying previously observed sequence motifs are placed into B*15 subgroups.

Twelve new B*15 alleles are described. All of the known B*15 alleles are divided into subgroups based on serologic assignments and/or nucleotide sequence polymorphisms. These groups might be used as a reference for DNA-based testing at an intermediate (i.e. "serologic") level of resolution.

Twenty-nine new HLA-B alleles associated with antigens in the 5C CREG.

This paper describes 29 novel HLA-B locus alleles identified during low-resolution typing. The majority of the novel alleles carry new patterns of previously known polymorphic motifs or codons. Three alleles carry alterations in the Bw4/Bw6 epitope. Five alleles carry novel substitutions.

Novel HLA-B alleles associated with antigens in the 7C CREG.

This paper describes 9 novel HLA-B locus alleles. All of the alleles carry sequence motifs observed in other HLA-B alleles.

Novel HLA-B alleles associated with antigens in the 8C CREG.

This paper describes 13 novel HLA-B locus alleles, B*0809, B*0812, B*0813, B*0814, B*14062, B*3804, B*3806, B*3914, B*3915, B*3918, B*3919, B*3920, and B*3922 which represent new patterns of known polymorphic residues.

New alleles in the B44 family including B*44022, B*44032, B*4411, B*4420, B*4421, B*4424, and B*8301.

Seven new HLA-B locus alleles have been described. B*44022 and B*44032 are silent substitutions altering known alleles. B*4411 carries a unique Bw4-like epitope. B*4420, B*4421, and B*4424 carry new combinations of motifs previously observed in other alleles. B*8301 appears to be the result of the replacement of exon 2 from B*4402 with exon 2 from B*5603.

Further diversity at HLA-A and -B loci identified in Afro-Caribbean potential bone marrow donors.

Two novel HLA-A and three novel HLA-B alleles were identified within a group of Afro-Caribbean individuals who were recruited as potential donors for the Anthony Nolan Bone Marrow Trust Register. HLA typing was performed on DNA extracted from peripheral blood mononuclear cells using sequence-specific oligonucleotide (SSO) probes for HLA-A and -B loci. Eight individuals analysed exhibited hybridisation patterns for which a type could not be assigned. DNA from these individuals was further typed by two methodologies: direct sequencing of PCR products and reference strand conformation analysis (RSCA). The direct sequencing results allowed the identification of new alleles but did not allow confirmation of the cis/trans orientation of the new sequence motifs identified. RSCA analysis confirmed the results obtained by SSO and direct sequencing and in addition confirmed the cis/trans orientation of the new sequences. One individual possesses a new A*30 allele--A*3008 and two individuals possess an identical new A*74 allele--A*7404. The three novel HLA-B alleles were identified in three individuals: B*0812, B*1554 and B*4503 respectively. For the remaining two samples, A*2612 was identified. At present Caucasoid individuals, and therefore Caucasoid phenotypes, are predominantly represented on the various different volunteer bone marrow donor registries. The examples presented here highlight the potential for identification of further polymorphisms within the HLA system as more individuals from the much-needed ethnic minorities are recruited onto bone marrow donor registers.

Diversity of alleles encoding HLA-B40: relative frequencies in united states populations and description of five novel alleles.

The frequency of each B*40 allele was determined by DNA sequencing in four major United States populations: Caucasians, African Americans, Asians/Pacific Islanders, and Hispanics. Thirty-two individuals from each ethnic group, who were previously described serologically as B40, B60, or B61, were randomly selected out of a pool of 82,979 unrelated individuals for allele characterization. Out of nine different B*40 alleles identified in this study, B*4001 and B*4002 were the two most frequent B*40 alleles in all the population groups. B*4001 was the primary B*40 allele seen in Caucasians (83%) and African Americans (76%), while B*4002 was found in the majority of Hispanics (62%). The distributions of both alleles were comparable in the Asian/Pacific Islander population. These two alleles were the only B*40 alleles detected in Caucasians while four to five additional B*40 alleles were seen in the other population groups. The other B*40 alleles detected in this study included: B*4003 and B*4010 in Asian/Pacific Islanders; B*4012 and B*4016 in African Americans; and B*4004, B*4006, and B*4027 in Hispanics. Analysis revealed significant differences between Hispanics and all other groups as well as between African Americans and Asian/Pacific Islanders. This report also describes five novel B*40 alleles: B*4019, B*4020, B*4024, B*4027, and B*4028.

In vitro analyses of diamond-like carbon coated stents. Reduction of metal ion release, platelet activation, and thrombogenicity.

Coronary artery stents can induce platelet activation by shear forces, contact to the biomaterial, and release of metal ions. This activation is one important trigger for thrombosis. Coating of stents is a possible approach to prevent this side effect. The purpose of this study was to evaluate in vitro the biocompatibility of stents coated with diamond-like carbon (DLC). Semiquantitative energy-dispersive X-ray microanalyses showed a complete coverage of the DLC stents. Flow cytometric analyses revealed a significantly higher increase of mean channel fluorescence intensity for the activation-dependent antigens CD62p and CD63 in non-coated compared to DLC-coated stents (p<0.05). Atomic adsorption spectrophotometry analyses revealed a significant release of nickel and chromium metal ions by non-coated stents over a storage period of 96 hours in human plasma (p<0.05). In contrast, only minimal concentrations of released ions could be detected in the case of DLC-coated stents. Similar observations were made with inductively coupled plasma mass spectrometry analyses. Here, high concentrations of molybdenum and manganese ions were released from non-coated stents (p<0.05), while release of these ions from DLC-coated stents was virtually undetectable (p=0.1 for molybdenum and p=0.4 for manganese). Coating of intracoronary stents with diamond-like carbon significantly improves biocompatibility. This biocompatible coating may therefore contribute to a reduction in thrombogenicity.

Seventeen more novel HLA-A locus alleles.

This paper describes seventeen novel HLA-A locus alleles: A*0106, *0235, *0236, *0237, *1105, *2302, *2303, *24032, *2422, *2424, *2503, *2613, *3007, *3203, *3204, *6809 and *6810. All alleles were identified due to unexpected probe reaction patterns during routine SSOP typing. Exons 2 and 3 of these alleles were subsequently characterized by DNA sequencing. The alleles represent a shuffling of sequence motifs, likely by interallelic conversion, expanding the diversity of the HLA system.

Novel HLA-A and HLA-B alleles.

Nine novel HLA-A and HLA-B alleles are described: A*2609, A*6803, A*6806, B*1539, B*1540, B*2712, B*4103, B*5109, and B*5603. Most appear to have arisen by gene conversion events. B*5603 appears to have arisen by a reciprocal recombination event joining exon 2 of a B*55/ *56 allele with exon 3 of a B*15 allele. Serologically, the antigen encoded by this allele types with broad B22- and Bw6-specific alloantisera. Also unique, the antigen encoded by B*2712 does not react with B27-specific alloantisera but does react with Bw6-specific alloantisera.