Left ventricular non-compaction as a potential source for cryptogenic ischemic stroke in the young : A case-control study

Background Up to 50% of ischemic strokes in the young after thorough diagnostic work-up remain cryptogenic or associated with low-risk sources of cardioembolism such as patent foramen ovale (PFO). We studied with cardiac magnetic resonance (CMR) imaging, whether left ventricular (LV) non-compaction-a possible source for embolic stroke due to sluggish blood flow in deep intertrabecular recesses-is associated with cryptogenic strokes in the young. Methods Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) is an international prospective multicenter case-control study of young adults (aged 18-49 years) presenting with an imaging-positive first-ever ischemic stroke of undetermined etiology. In this pilot substudy, 30 cases and 30 age- and sex-matched stroke-free controls were examined with CMR. Transcranial Doppler (TCD) bubble test was performed to evaluate the presence and magnitude of right-to-left shunt (RLS). Results There were no significant differences in LV volumes, masses or systolic function between cases and controls; none of the participants had non-compaction cardiomyopathy. Semi-automated assessment of LV non-compaction was highly reproducible. Non-compacted LV mass (median 14.0 [interquartile range 12.6-16.0] g/m(2)vs. 12.7 [10.4-16.6] g/m(2), p = 0.045), the ratio of non-compacted to compacted LV mass (mean 25.6 +/- 4.2% vs. 22.8 +/- 6.0%, p = 0.015) and the percentage of non-compacted LV volume (mean 17.6 +/- 2.9% vs. 15.7 +/- 3.8%, p = 0.004) were higher in cases compared to controls. In a multivariate conditional logistic regression model including non-compacted LV volume, RLS and body mass index, the percentage of non-compacted LV volume (odds ratio [OR] 1.55, 95% confidence interval [CI] 1.10-2.18, p = 0.011) and the presence of RLS (OR 11.94, 95% CI 1.14-124.94, p = 0.038) were independently associated with cryptogenic ischemic stroke. Conclusions LV non-compaction is associated with a heightened risk of cryptogenic ischemic stroke in young adults, independent of concomitant RLS and in the absence of cardiomyopathy.Peer reviewe

Right atrium and cryptogenic ischaemic stroke in the young : A case-control study

Publisher Copyright: © 2021 BMJ Publishing Group. All rights reserved.Background Recent studies suggest left atrial (LA) dysfunction in cryptogenic stroke. We studied the dynamics of right atrium (RA) and right atrial appendage (RAA) in young adults with cryptogenic stroke. We hypothesised that bi-atrial dysfunction and blood stagnation might contribute to thrombosis formation in patients with patent foramen ovale (PFO), as deep venous thrombosis is detected only in the minority of patients. Methods Thirty patients (aged 18-49) with a first-ever cryptogenic stroke and 30 age-matched and sex-matched stroke-free controls underwent cardiac magnetic resonance (CMR) imaging. An approach to estimate the RAA volume was developed, using crista terminalis and pectinate muscles as anatomical landmarks. Atrial expansion indices were calculated as (maximal volume - minimal volume) ×100%/minimal volume. Total pulmonary to systemic blood flow ratio (Qp/Qs) was based on phase contrast CMR. Right-to-left shunt (RLS) was evaluated with transoesophageal echocardiography in 29 patients and transcranial Doppler in 30 controls, moderate-to-severe RLS considered as clinically significant. Results We found that RA and RAA volumes were similar between patients and controls. Also, RA expansion index was similar, but RAA (95.6%±21.6% vs 108.7%±25.8%, p=0.026) and LA (126.2%±28% vs 144.9%±36.3%, p=0.023) expansion indices were lower in patients compared with controls. Seven (24%) of 29 patients had an RLS compared with 1 (3%) of 30 controls (p=0.012). Among 59 study subjects, RLS was associated with lower RA (81.9%±15.9% vs 98.5%±29.5%, p=0.030), RAA (84.7%±18% vs 105.6%±24.1%, p=0.022), LA (109.8%±18.6% vs 140.1%±33.7%, p=0.017) and LAA (median 102.9% (IQR 65.6%-121.7%) vs 229.1% (151.8%-337.5%], p=0.002) expansion indices and lower Qp/Qs ratio (0.91±0.06 vs 0.98±0.07, p=0.027). Conclusions This study suggests bi-atrial dysfunction in young adults with cryptogenic stroke, associated with moderate-to-severe RLS. Dysfunction of the atria and atrial appendages may be an additional mechanism for PFO-related stroke. Trial registration number NCT01934725.Peer reviewe

Revisiting left atrial volumetry by magnetic resonance imaging : the role of atrial shape and 3D angle between left ventricular and left atrial axis

Background Accurate measurement of left atrial (LA) volumes is needed in cardiac diagnostics and the follow up of heart and valvular diseases. Geometrical assumptions with 2D methods for LA volume estimation contribute to volume misestimation. In this study, we test agreement of 3D and 2D methods of LA volume detection and explore contribution of 3D LA axis orientation and LA shape in introducing error in 2D methods by cardiovascular magnetic resonance imaging. Methods 30 patients with prior first-ever ischemic stroke and no known heart disease, and 30 healthy controls were enrolled (age 18-49) in a substudy of a prospective case-control study. All study subjects underwent cardiac magnetic resonance imaging and were pooled for this methodological study. LA volumes were calculated by biplane area-length method from both conventional long axis (LAV(AL-LV)) and LA long axis-oriented images (LAV(AL-LA)) and were compared to 3D segmented LA volume (LAV(SAX)) to assess accuracy of volume detection. 3D orientation of LA long axis to left ventricular (LV) long axis and to four-chamber plane were determined, and LA 3D sphericity indices were calculated to assess sources of error in LA volume calculation. Shapiro-Wilk test, Bland-Altman analysis, intraclass and Pearson correlation, and Spearman's rho were used for statistical analysis. Results Biases were - 9.9 mL (- 12.5 to - 7.2) for LAV(AL-LV) and 13.4 (10.0-16.9) for LAV(AL-LA) [mean difference to LAV(SAX) (95% confidence interval)]. End-diastolic LA long axis 3D deviation angle to LV long axis was 28.3 +/- 6.2 degrees [mean +/- SD] and LA long axis 3D rotation angle to four-chamber plane 20.5 +/- 18.0 degrees. 3D orientation of LA axis or 3D sphericity were not correlated to error in LA volume calculation. Conclusions Calculated LA volume accuracy did not improve by using LA long axis-oriented images for volume calculation in comparison to conventional method. We present novel data on LA axis orientation and a novel metric of LA sphericity and conclude that these measures cannot be utilized to assess error in LA volume calculation.Peer reviewe

Bifidobacterium animalis

Gastrointestinal (GI) adverse effects such as erosion and increased permeability are common during the use of nonsteroidal anti-inflammatory drugs (NSAIDs). Our objective was to assess whether Bifidobacterium animalis ssp. lactis 420 protects against NSAID-induced GI side effects in a rat model. A total of 120 male Wistar rats were allocated into groups designated as control, NSAID, and probiotic. The NSAID and probiotic groups were challenged with indomethacin (10 mg/kg−1; single dose). The probiotic group was also supplemented daily with 1010 CFU of B. lactis 420 for seven days prior to the indomethacin administration. The control group rats received no indomethacin or probiotic. The permeability of the rat intestine was analysed using carbohydrate probes and the visual damage of the rat stomach mucosa was graded according to severity. B. lactis 420 significantly reduced the indomethacin-induced increase in stomach permeability. However, the protective effect on the visual mucosal damage was not significant. The incidence of severe NSAID-induced lesions was, nevertheless, reduced from 50% to 33% with the probiotic treatment. To conclude, the B. lactis 420 supplementation protected the rats from an NSAID-induced increase in stomach permeability and may reduce the formation of more serious GI mucosal damage and/or enhance the recovery rate of the stomach mucosa

Genetic basis of congenital nephrotic syndrome and generation of an animal model

Congenital nephrotic syndrome, NPHS1, is a disease highly enriched in Finland with incidence of 1:82oo births.The disease is characterized by massive proteinuria, go % of which is albumin, starting in utero, large placenta, which weighs over 25 % of the child's birth weight, and manifestation of proteinuria soon after birth. Historically, NPHS1 children have died before the age Of 2, but an aggressive nutritional therapy together with kidney transplantation can today save the life of the child. Irregular dilation of proximal and distal tubules and irregular fusion of podocyte foot processes are the most typical findings from histological and ultrastructural studies, respectively. The homogenous population structure of Finns, with the presence of a founder effect and substantial isolation, was utilized in attempts to clone the disease causing gene using linkage disequilibrium. Linkage disequilibrium is an efficient tool for positional cloning and can be used to narrow down the critical chromosomal region into which the disease gene is first linked. Haplotype sharing analysis of genetic markers, which were found to be in linkage disequilibrium in the critical region of the disease gene 19q13.1, was used in specific prenatal diagnosis Of NPHS1. Four main categories of haplotypes in Finnish NPHS1 patients were found, prenatal diagnosis being 95 % accurate in the Finnish families with history Of NPHS1. The 150 kb chromosomal region containing the NPHS1 gene was sequenced entirely and the sequence data was subsequently subjected to computer-based exon prediction. Over 100 potential exons and at least ten novel genes were found in this region, four of which were subjected to mutation search. One of the genes bore mutations, two of which comprise over go % of the Finnish NPHS1 chromosomes either as homozygote or compound heterozygote. The more common mutationFinmajor-is a deletion in exon 2 and results in a frameshift, which generates a stop codon within the same exon. The second mutation-Fin minor -is a nonsense mutation in exon 26. The protein product of the NPHS1 gene, named nephrin, comprises 1241 residues and is, based on its predicted domain structure, a member of the immunoglobulin superfamily. The gene was first shown by Northern hybridization analysis to be expressed solely in human embryonic and adult kidney and then by in situ analysis in human embryonic kidney in the periphery of mature and developing glomeruli of the kidney. The primary sequence of mouse and rat nephrin homologs were obtained from CDNA Clones. The sequence identity between rat and mouse proteins was about 93 %, both rodent protein sequences showing about 83 % identity to overlapping human protein regions. The predicted domain structures of nephrin of these species are similar to that of human. The in situ analysis of mouse nephrin showed that at the embryonic day 11 the cranial tubules of the mesonephric kidney with podocyte- like structures were strongly positive. Expression was seen in metanephros from E13 in late s-shaped bodies in presumptive podocytes. Expression was also seen at Ell in the hindbrain area continuing dorsally in the mantle layer neurons of the spinal cord. From E13 to E17, signal was detected in the neuroepithelium of the cerebellum primordium at the roof of the fourth ventricle. The epithelial cells of the developing choroid plexus remained negative at all stages. A mouse model with targeted inactivation of the nephrin gene was generated in order to study the expression pattern in more detail with the beta-galactosidase gene inserted in frame to nephrin exon 1. The different genotypes were born in expected ratios, and inactivation of the nephrin gene was confirmed with Western analyses of extracted kidney proteins. The null allele animals, however, became edemic soon after birth and died within 24 hours. Protein analysis of the urine showed extensive proteinuria, most of the protein being albumin. Histological and ultrastuctural findings in the kidney were similar to human NPHS1, thus confirming that a mouse model Of NPHS1 was generated. The expression of beta-galactosidase was observed, in addition to kidney, transiently in the developing spinal cord and pancreas, in main olfactory bulb glomeruli, in hippocampal dentate gyrus, and in cerebellum. In newborn mice, nephrin was localized to radial glial cells. Histological analysis of newborn mice brain revealed no substantial abnormalities in the cerebellum

Tekniikat iskeemisen aivoverenkiertohäiriön etiologisessa selvittelyssä

Teema : aivoinfarkti. English summaryPeer reviewe

Resonator‐enhanced radiating cable for UHF RFID readers

Abstract An antenna cable for enhancing and adjusting radio coverage is proposed. The presented solution is applied to the UHF RFID range of 866 MHz. With this leaky‐wave antenna cable, radio coverage can be efficient and customizable. A 10 × 100 mm resonator patch is attached on an opening on the cable’s outer conductor to improve its radiating properties. The effect of its displacement is studied through simulations and measurements. The alignment affects both resonance frequency and signal strength. One resonator increases the radiated power by 2 dB (37%), multipliable by adding resonators. However, alignment accuracy of millimeters is needed in many cases. The greatest effect in both operating frequency and transmission loss magnitude comes from lifting the resonator from the cable’s surface, averagely being 7.6% and 8.6% per mm in measured operating frequency and linear magnitude of S21, respectively. Smallest changes are observed when moving the resonator along the cable, being 0.8% and 0.7% per mm, respectively

A resonator enhanced UHF RFID antenna cable for inventory and warehouse applications

Abstract Structures to improve the RF properties of leaky coaxial cables (LCX) are proposed. These resonator structures are optimized for UHF RFID frequency of 866 MHz; however, they are applicable also to other frequencies of interest by redimensioning with corresponding data. Simulations of leaky coaxial cables with resonators (denoted “RCX”) show to improve the antenna gain, which is verified also by measurements. Compared to traditional LCX, RCX have increased radiating power capability while the shape of the propagated wave is also controlled. Cables are simulated with lengths 2.1 m and 6.4 m where the number of radiating slots and resonators is varied. RCXs exhibit a much higher radiation capability than LCXs. The radiation efficiency for RCXs is between 40% ⋯60 % whereas an LCX has only 0.2% efficiency. Simulations are complemented with measurements of the 2.1 m cables. A 30x improvement of the read range of passive RFID tags are reported in tests, from 0.05 m to 1.5 m along the resonator cable. The cable length can be extended so that the signal is carried to the radiating point of the cable using conventional, i.e., non-radiating coaxial cable

Materials for electronics by thermal spraying

In this paper, dielectric and conductive properties of thermally sprayed Al2O3- and Cu-based coatings on steel and alumina substrates were studied. Alumina powders with nanoand micro-sized additions of Ni, NiO, TiO2, silica, and commercial glass were used in High Velocity Oxygen Fuel (HVOF) deposition. The conventional commercial copper powder and three Ag, WC and H2 -modified powders were used in Direct Write Thermal Spray (DWTS) deposition. Mixed phases of α-Al2O3 and γ-Al2O3 were found to be present in the as-deposited coatings. Sprayed alumina-based composites exhibited dielectric permittivity of 5.3-13.9 and losses of 0.002-0.178 at 1 MHz and 1 GHz while the additions tend to increase the values. Sprayed compositions with glass-type additions were found to retain α-Al2O3 crystalline phase after the deposition. Cu depositions, especially modified ones, realised by Direct Write Thermal Spray (DWTS) showed conductivity values as high as 4256 % of IACS values. The results demonstrate that ceramic and conductive coatings fabricated by thermal spray techniques show feasible properties for electrical applications, such as low-frequency components and insulation layers to be utilised in embedded 3D circuitry, in a way that is not possible through traditional manufacturing methods.</jats:p