Multiple repeat caesarean deliveries: do they increase maternal and neonatal morbidity?

Objective: The aim of the present study is to evaluate the effects of the increased number of caesarean deliveries (CDs) in cases of multiple repeat caesarean deliveries (MRCDs) on maternal and neonatal morbidity.

Methods: MRCDs admitted to our hospital between January 2013 and September 2014 were analysed retrospectively. A total number of 1133 women were included in the study and were divided into 4 groups. Group 1: second CDs (n?=?329); Group 2: third CDs (n?=?225); Group 3: fourth CDs (n?=?447); Group 4: fifth CDs (n?=?132). The clinical, demographic, intraoperative and postoperative data of the patients were registered upon the review of patient files.

Results: The differences among the groups were found to be statistically significant in terms of mean maternal age, gravida, APGAR (Activity, Pulse, Grimace, Appearance, Respiration) scores, hospital stay and operation time. In addition, the difference was also statistically significant for severe adhesion, bladder injury and premature birth. No statistically significant difference was observed among the groups with respect to placenta previa, placenta accreta, caesarean hysterectomy, uterine scar rupture.

Conclusions: According to our findings, MRCDs seem to increasing the maternal and neonatal morbidity even though they are not life-threatening.     

Optimal design of oligonucleotide microarrays for measurement of DNA copy-number

Copy-number variants (CNVs) occur frequently within the human genome, and may be associated with many human phenotypes. If disease association studies of CNVs are to be performed routinely, it is essential that the copy-number status be accurately genotyped. We systematically assessed the dynamic range response of an oligonucleotide microarray platform to accurately predict copy-number in a set of seven patients who had previously been shown to carry between 1 and 6 copies of an approximately 4 Mb region of 15q12.2-q13.1. We identify probe uniqueness, probe length, uniformity of probe melting temperature, overlap with SNPs and common repeats (particularly Alu elements) and guanine homopolymer content as parameters that significantly affect probe performance. Further, we prove the influence of these criteria on array performance by using these parameters to prospectively filter data from a second array design covering an independent genomic region and observing significant improvements in data quality. The informed selection of probes which have superior performance characteristics allows the prospective design of oligonucleotide arrays which show increased sensitivity and specificity compared with current designs. Although based on the analysis of data from comparative genomic hybridization experiments, we anticipate that our results are relevant to the design of improved oligonucleotide arrays for high-throughput copy-number genotyping of complex regions of the human genome.     

Facial asymmetry in young healthy subjects evaluated by statistical shape analysis

Statistical shape analysis, a relatively a new method for biological research, compares body forms by using specific landmarks determined by anatomical prominences. In this study, we aimed to identify normal facial asymmetry between the right and the left sides of the face. Facial landmark data were collected from two‐dimensional digital images of 321 young healthy subjects (150 males and 171 females). These data were analysed using Euclidean distance matrix analysis. The number of significantly asymmetric linear distances between the two halves of the face was greater in females than in males. We found that the left side of the face was most commonly dominant in both males and females. Such data may be useful in establishing a database for future similar studies.     

Genome-wide characterization of centromeric satellites from multiple mammalian genomes

Despite its importance in cell biology and evolution, the centromere has remained the final frontier in genome assembly and annotation due to its complex repeat structure. However, isolation and characterization of the centromeric repeats from newly sequenced species are necessary for a complete understanding of genome evolution and function. In recent years, various genomes have been sequenced, but the characterization of the corresponding centromeric DNA has lagged behind. Here, we present a computational method (RepeatNet) to systematically identify higher-order repeat structures from unassembled whole-genome shotgun sequence and test whether these sequence elements correspond to functional centromeric sequences. We analyzed genome datasets from six species of mammals representing the diversity of the mammalian lineage, namely, horse, dog, elephant, armadillo, opossum, and platypus. We define candidate monomer satellite repeats and demonstrate centromeric localization for five of the six genomes. Our analysis revealed the greatest diversity of centromeric sequences in horse and dog in contrast to elephant and armadillo, which showed high-centromeric sequence homogeneity. We could not isolate centromeric sequences within the platypus genome, suggesting that centromeres in platypus are not enriched in satellite DNA. Our method can be applied to the characterization of thousands of other vertebrate genomes anticipated for sequencing in the near future, providing an important tool for annotation of centromeres.     

Comparative analysis of Alu repeats in primate genomes

Using bacteria artificial chromosome (BAC) end sequences (16.9 Mb) and high-quality alignments of genomic sequences (17.4 Mb), we performed a global assessment of the divergence distributions, phylogenies, and consensus sequences for Alu elements in primates including lemur, marmoset, macaque, baboon, and chimpanzee as compared to human. We found that in lemurs, Alu elements show a broader and more symmetric sequence divergence distribution, suggesting a steady rate of Alu retrotransposition activity among prosimians. In contrast, Alu elements in anthropoids show a skewed distribution shifted toward more ancient elements with continual declining rates in recent Alu activity along the hominoid lineage of evolution. Using an integrated approach combining mutation profile and insertion/deletion analyses, we identified nine novel lineage-specific Alu subfamilies in lemur (seven), marmoset (one), and baboon/macaque (one) containing multiple diagnostic mutations distinct from their human counterparts—Alu J, S, and Y subfamilies, respectively. Among these primates, we show that that the lemur has the lowest density of Alu repeats (55 repeats/Mb), while marmoset has the greatest abundance (188 repeats/Mb). We estimate that ∼70% of lemur and 16% of marmoset Alu elements belong to lineage-specific subfamilies. Our analysis has provided an evolutionary framework for further classification and refinement of the Alu repeat phylogeny. The differences in the distribution and rates of Alu activity have played an important role in subtly reshaping the structure of primate genomes. The functional consequences of these changes among the diverse primate lineages over such short periods of evolutionary time are an important area of future investigation.Alu repeats are primate-specific short interspersed sequence elements (SINEs), ∼300 nt in length, propagating within a genome through retrotransposition (Schmid 1996). They are the most abundant repeat sequences found in humans, with more than 1.1 million copies accounting for ∼10% of the human genome sequence (Lander et al. 2001). Recent work increasingly recognizes that Alu elements have a greater impact than expected on phenotypic change, diseases, and evolution. Alu elements were demonstrated to mediate insertion mutagenesis, “exonization” by alternative splicing, genomic rearrangements, segmental duplication, and expression regulation causing disorders like Hunter syndrome, hemophilia A, and Sly syndrome (Batzer and Deininger 2002). The oldest Alu elements were estimated to emerge either coincident with or immediately after the radiation of primates. Based on Alu subfamily sequence diversity, a major burst in Alu amplification was estimated to have occurred 25–50 million years ago (Mya) (Shen et al. 1991). Younger Alu repeat elements have emerged in the hominoid, although the rate of more recent retrotransposition events has declined (Batzer and Deininger 2002). Owing to their unidirectional mode of evolution, SINE insertions have been used as largely homoplasy-free character states in cladistic analyses of primates (Schmitz et al. 2001; Roos et al. 2004). Alu insertion loci have also been used to clarify relationships among New World monkeys (NWM), Old World monkeys (OWM), and the human–chimpanzee–gorilla trichotomy (Salem et al. 2003; Ray and Batzer 2005; Ray et al. 2005; Xing et al. 2005).Alu elements in human lineage have been extensively characterized (Batzer and Deininger 2002). They are divided into subfamilies based on the extent of sequence diversity and diagnostic mutations (Britten et al. 1988; Jurka and Smith 1988). The monomeric repeats (such as FAM, FRAM, and FLAM) are the oldest Alu-related elements derived from the 7SL RNA gene. The more recent dimeric Alu elements consist of two similar but not identical monomers with a short adenine-rich linker between the two monomers and a longer and more variable A-rich region at the 3′-end. The various dimeric Alu subfamilies have been identified in different evolutionary ages with overlap. AluJo and AluJb are the most ancient Alu dimeric subfamilies. AluS represents the major burst of Alu elements, which contains subfamilies such as Sx, Sp, Sq, Sg, and Sc, with Sx being the most common. AluY is the youngest subfamily in the hominoid lineage, which continues to retrotranspose, and is subsequently polymorphic in the population. Pevzner and colleagues identified 213 human Alu subfamilies at a much finer resolution using a novel method (Alucode) (Price et al. 2004). This method first split Alu subfamilies based on “biprofiles,” that is, linkage of pairs of nucleotide values, and then used the calibration of Alu mutation rates to split subfamilies containing overrepresented individual mutations. These observations generally support the master-gene hypothesis for Alu amplifications, i.e., Alu subfamilies originated through successive waves of fixation from sequential small subsets of master elements (Batzer and Deininger 2002).To date, genome-wide characterization of Alu repeats in nonhuman primates has been limited to chimpanzee and macaque (The Chimpanzee Sequencing and Analysis Consortium 2005; Gibbs et al. 2007). Most chimpanzee-specific elements belong to a subfamily (AluYc1) that is very similar to the source gene in the human–chimpanzee last common ancestor. In macaque, Alu elements have evolved into four currently active lineages: AluYRa1-4, AluYRb1-4, AluYRc1-2, and AluYRd1-4 (Han et al. 2007). Currently, there are three macaque consensus sequences: AluMacYa3, AluMacYb2, and AluMAcYb4 in Repbase (Version 13.5). For other primate genomes, most studies have been based on PCR cross-amplification among diverse primate taxa and, therefore, are potentially biased to either conserved regions or limited to closely related species. Ray and Batzer (2005) recovered 48 NWM-specific Alu elements using a combination of PCR and computational approaches and reported three NWM-specific subfamilies: AluTa7, AluTa10, and AluTa1. In another publication, Herke et al. (2007) reported a few loci (such as {"type":"entrez-nucleotide","attrs":{"text":"DQ822065","term_id":"112418420","term_text":"DQ822065"}}DQ822065) from the lemur derived from PCR display. Initial comparative analysis based on small samples of primate genomic sequences demonstrated that the fixation rates of retroelements (especially SINE/Alu) vary radically in different primate lineages (Liu et al. 2003; Hedges et al. 2004). In this study, we analyze Alu elements in randomly sampled BAC end sequences (BES) and finished genomic sequence alignments (ALN) from five nonhuman primates—lemur, marmoset, macaque, baboon, and chimpanzee—using two distinct approaches combining mutation profile and insertion/deletion analysis. The five species, including great apes (chimpanzee), OWM (baboon and macaque), NWM (marmoset), and prosimians (lemur), are estimated to have diverged from humans at distant time points, ∼6, 25, 25, 35, and 55 Mya, respectively (Goodman 1999). Thus, this spectrum of the taxa provides a vista of Alu-element changes at different nodes during primate evolution.     

Photoinduced Cu(0)‐Mediated Atom Transfer Radical Polymerization

Photoinduced Cu(0)‐mediated atom transfer radical polymerization (ATRP) of methyl methacrylate is investigated by using Cu(0)/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the catalyst, ethyl 2‐bromopropionate as the initiator, and dimethyl sulfoxide as the solvent. The effect of light on the conventional Cu(0)‐mediated ATRP and molecular weight characteristics of the obtained polymers are described. Although the polymerization can be achieved in the absence of light, low initiation efficiency of the process is observed. By introducing UV light and additional Cu(II) deactivator, not only the rate of polymerization is increased, but also well‐controlled polymers with narrow‐molecular‐weight distributions at ambient conditions are obtained. The chain extension study clearly confirms high end‐group fidelity of the polymer that is active in the further polymerization process.

     

Comparison of demographic and clinical characteristics of hospitalized COVID-19 patients with severe/critical illness in the first wave versus the second wave

Due to current advances and growing experience in the management of coronavirus Disease 2019 (COVID-19), the outcome of COVID-19 patients with severe/critical illness would be expected to be better in the second wave compared with the first wave. As our hospitalization criteria changed in the second wave, we aimed to investigate whether a favorable outcome occurred in hospitalized COVID-19 patients with only severe/critical illness. Among 642 laboratory-confirmed hospitalized COVID-19 patients in the first wave and 1121 in the second wave, those who met World Health Organization (WHO) definitions for severe or critical illness on admission or during follow-up were surveyed. Data on demographics, comorbidities, C-reactive protein (CRP) levels on admission, and outcomes were obtained from an electronic hospital database. Univariate analysis was performed to compare the characteristics of patients in the first and second waves. There were 228 (35.5%) patients with severe/critical illness in the first wave and 681 (60.7%) in the second wave. Both groups were similar in terms of age, gender, and comorbidities, other than chronic kidney disease. Median serum CRP levels were significantly higher in patients in the second wave compared with those in the first wave [109 mg/L (interquartile range [IQR]: 65–157) vs. 87 mg/L (IQR: 39–140); p < 0.001]. However, intensive care unit admission and mortality rates were similar among the waves. Even though a lower mortality rate in the second wave has been reported in previous studies, including all hospitalized COVID-19 patients, we found similar demographics and outcomes among hospitalized COVID-19 patients with severe/critical illness in the first and second wave.     

Pericardiacophrenic shunt: imaging finding of rare splenosystemic collateral. Case report

Portosystemic collaterals are the natural consequence of portal hypertension. These collaterals can occur anywhere in the gastrointestinal tract. Apart from the usual sites, they can develop in some unusual and rare locations. In this report, imaging findings of an unusual venous collateral pathway between spleen and left subclavian vein in a 30-year-old female patient with cirrhosis and portal hypertension are presented.     

Decorin: a possible marker for fetal growth restriction

The aim of this study was to compare decorin (DCN) levels between pregnancies complicated by idiopathic fetal growth restriction (FGR) and uncomplicated pregnancies and to determine the relationship between DCN levels and clinical parameters. The study population consisted of two groups: control group consisted of 13 women with uncomplicated singleton pregnancies in the third trimester. Study group consisted of 14 singleton pregnancies complicated by idiopathic FGR who were admitted to the hospital for delivery in the third trimester of pregnancy. Maternal and fetal DCN levels were measured. Color Doppler flow assessments were performed. Relationship between DCN levels and clinical parameters was determined. Maternal DCN serum levels were significantly higher in complicated pregnancies by idiopathic FGR (p?=?0.01). A statistically significant negative correlation was observed between maternal DCN serum levels and neonatal birth weight (r?=??0.0506; p?=?0.007). There was a significant correlation between umbilical artery (UA) DCN levels and UA S/D ratio (r?=?0.512; p?=?0.006) and UA RI (r?=?0.405; p?=?0.036). The risk of high DCN maternal serum levels (>7986.6?pg/mL) in pregnancy complicated by FGR was 8.25 times higher (RR?=?8.25; 95% CI, 1.4–46.8). The results of our study showed that the presence of increased DCN levels in women with FGR could contribute to pathogenesis of the disease.