Altered chromatin structure associated with methylation-induced gene silencing in cancer cells: correlation of accessibility, methylation, MeCP2 binding and acetylation

Silencing of tumor-suppressor genes by hypermethylation of promoter CpG islands is well documented in human cancer and may be mediated by methyl-CpG-binding proteins, like MeCP2, that are associated in vivo with chromatin modifiers and transcriptional repressors. However, the exact dynamic between methylation and chromatin structure in the regulation of gene expression is not well understood. In this study, we have analyzed the methylation status and chromatin structure of three CpG islands in the p14(ARF)/p16(INK4A) locus in a series of normal and cancer cell lines using methylation-sensitive digestion, MspI accessibility in intact nuclei and chromatin immunoprecipitation (ChIP) assays. We demonstrate the existence of an altered chromatin structure associated with the silencing of tumor-suppressor genes in human cancer cell lines involving CpG island methylation, chromatin condensation, histone deacetylation and MeCP2 binding. The data showed that MeCP2 could bind to methylated CpG islands in both promoters and exons; MeCP2 does not interfere with transcription when bound at an exon, suggesting a more generalized role for the protein beyond transcriptional repression. In the absence of methylation, it is demonstrated that CpG islands located in promoters versus exons display marked differences in the levels of acetylation of associated histone H3, suggesting that chromatin remodeling can be achieved by methylation-independent processes and perhaps explaining why non-promoter CpG islands are more susceptible to de novo methylation than promoter islands.

Experimental demonstration of memory-enhanced quantum communication

The ability to communicate quantum information over long distances is of central importance in quantum science and engineering¹. Although some applications of quantum communication such as secure quantum key distribution^2,3 are already being successfully deployed^4-7, their range is currently limited by photon losses and cannot be extended using straightforward measure-and-repeat strategies without compromising unconditional security⁸. Alternatively, quantum repeaters⁹, which utilize intermediate quantum memory nodes and error correction techniques, can extend the range of quantum channels. However, their implementation remains an outstanding challenge^10-16, requiring a combination of efficient and high-fidelity quantum memories, gate operations, and measurements. Here we use a single solid-state spin memory integrated in a nanophotonic diamond resonator^17-19 to implement asynchronous photonic Bell-state measurements, which are a key component of quantum repeaters. In a proof-of-principle experiment, we demonstrate high-fidelity operation that effectively enables quantum communication at a rate that surpasses the ideal loss-equivalent direct-transmission method while operating at megahertz clock speeds. These results represent a crucial step towards practical quantum repeaters and large-scale quantum networks^20,21.

Roles of cell division and gene transcription in the methylation of CpG islands

De novo methylation of CpG islands within the promoters of eukaryotic genes is often associated with their transcriptional repression, yet the methylation of CpG islands located downstream of promoters does not block transcription. We investigated the kinetics of mRNA induction, demethylation, and remethylation of the p16 promoter and second-exon CpG islands in T24 cells after 5-aza-2'-deoxycytidine (5-Aza-CdR) treatment to explore the relationship between CpG island methylation and gene transcription. The rates of remethylation of both CpG islands were associated with time but not with the rate of cell division, and remethylation of the p16 exon 2 CpG island occurred at a higher rate than that of the p16 promoter. We also examined the relationship between the remethylation of coding sequence CpG islands and gene transcription. The kinetics of remethylation of the p16 exon 2, PAX-6 exon 5, c-ABL exon 11, and MYF-3 exon 3 loci were examined following 5-Aza-CdR treatment because these genes contain exonic CpG islands which are hypermethylated in T24 cells. Remethylation occurred most rapidly in the p16, PAX-6, and c-ABL genes, shown to be transcribed prior to drug treatment. These regions also exhibited higher levels of remethylation in single-cell clones and subclones derived from 5-Aza-CdR-treated T24 cells. Our data suggest that de novo methylation is not restricted to the S phase of the cell cycle and that transcription through CpG islands does not inhibit their remethylation.

Silicon-Vacancy Spin Qubit in Diamond: A Quantum Memory Exceeding 10 ms with Single-Shot State Readout

The negatively charged silicon-vacancy (SiV^{-}) color center in diamond has recently emerged as a promising system for quantum photonics. Its symmetry-protected optical transitions enable the creation of indistinguishable emitter arrays and deterministic coupling to nanophotonic devices. Despite this, the longest coherence time associated with its electronic spin achieved to date (∼250  ns) has been limited by coupling to acoustic phonons. We demonstrate coherent control and suppression of phonon-induced dephasing of the SiV^{-} electronic spin coherence by 5 orders of magnitude by operating at temperatures below 500 mK. By aligning the magnetic field along the SiV^{-} symmetry axis, we demonstrate spin-conserving optical transitions and single-shot readout of the SiV^{-} spin with 89% fidelity. Coherent control of the SiV^{-} spin with microwave fields is used to demonstrate a spin coherence time T_{2} of 13 ms and a spin relaxation time T_{1} exceeding 1 s at 100 mK. These results establish the SiV^{-} as a promising solid-state candidate for the realization of quantum networks.

Quantum Nonlinear Optics with a Germanium-Vacancy Color Center in a Nanoscale Diamond Waveguide

We demonstrate a quantum nanophotonics platform based on germanium-vacancy (GeV) color centers in fiber-coupled diamond nanophotonic waveguides. We show that GeV optical transitions have a high quantum efficiency and are nearly lifetime broadened in such nanophotonic structures. These properties yield an efficient interface between waveguide photons and a single GeV center without the use of a cavity or slow-light waveguide. As a result, a single GeV center reduces waveguide transmission by 18±1% on resonance in a single pass. We use a nanophotonic interferometer to perform homodyne detection of GeV resonance fluorescence. By probing the photon statistics of the output field, we demonstrate that the GeV-waveguide system is nonlinear at the single-photon level.

Analysis of cyclin-dependent kinase inhibitor expression and methylation patterns in human prostate cancers

BACKGROUND

Downregulation of genes which negatively control cell cycle progression represents a possible mechanism for prostate tumorigenesis. We examined the expression levels of the p16, p15, p14, and retinoblastoma-susceptibility (RB) genes in primary prostate cancers and human prostate cancer cell lines, and correlated this with the DNA methylation levels of two loci in p16.

METHODS

The mRNA levels of p16, p15, and p14 were examined by reverse transcriptase-PCR (RT-PCR). DNA methylation of the p16 5' CpG island was determined by bisulfite genomic sequencing, while methylation of exon 2 shared by the p16 and p14 genes was measured by a quantitative bisulfite-based technique, methylation-sensitive single-nucleotide primer extension (Ms-SNuPE). RB protein levels were assessed by immunohistochemical staining of histologic sections of normal and tumor prostate tissues, using a monoclonal antibody (mAB).

RESULTS

Overexpression of p16 mRNA was found in 6/9 (67) of prostate tumors compared to the adjacent normal prostate, whereas elevated p14 and p15 levels were only observed in 2/9 (22) and 1/6 (17) of prostate cases, respectively. There was no statistically significant association of grade (P = 0.18) and stage (P = 1.00) of prostate cancer to the elevated p16 levels in the tumors. The p16 5' CpG island was completely unmethylated in these tissues. In contrast, exon 2 of p16/p14 was methylated in both the tumor and normal adjacent prostates, and was increased in 8/11 (73) of tumors relative to normal tissues. There was no association between p16 overexpression and increased p16/p14 exon 2 methylation in these tumors (P = 1.00). Diminished RB levels in prostate tumors that had upregulated p16 mRNA were found, although absent RB was also detected in tumors without elevated p16 levels. The expression levels of the two genes, RB and p16, were not correlated statistically (P = 0.16).

CONCLUSIONS

Our studies show that although the levels of the cell cycle regulators p16, p15, p14, and Rb are altered in prostate cancers, there is no apparent correlation to grade, stage, or any pattern of regulation between the related genes. Exon 2 of p16/p14 is methylated in a majority of prostate tumors compared to the unmethylated upstream 5' region, and may be a potential tumor marker for human prostate cancer.

Quantum Network Nodes Based on Diamond Qubits with an Efficient Nanophotonic Interface

Quantum networks require functional nodes consisting of stationary registers with the capability of high-fidelity quantum processing and storage, which efficiently interface with photons propagating in an optical fiber. We report a significant step towards realization of such nodes using a diamond nanocavity with an embedded silicon-vacancy (SiV) color center and a proximal nuclear spin. Specifically, we show that efficient SiV-cavity coupling (with cooperativity C>30) provides a nearly deterministic interface between photons and the electron spin memory, featuring coherence times exceeding 1 ms. Employing coherent microwave control, we demonstrate heralded single photon storage in the long-lived spin memory as well as a universal control over a cavity-coupled two-qubit register consisting of a SiV and a proximal ^{13}C nuclear spin with nearly second-long coherence time, laying the groundwork for implementing quantum repeaters.

Prognosis and prediction of response to surgery in allergic patients with chronic sinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) occurs frequently in patients with atopy, but little is known of the prognosis after surgery and of factors that may predict a poor outcome.

OBJECTIVE

Our purpose was to assess the long-term prognosis in atopic patients with CRS who undergo surgery and whether certain immune markers could predict a worse prognosis in this setting.

METHODS

Fifteen patients with diffuse involvement of the sinuses on computed tomographic (CT) scan but without nasal polyposis underwent ethmoidectomy with middle meatotomy for CRS when it was clinically indicated. All patients had a biopsy of the inferior turbinate and of the most inflamed areas of the maxillary and ethmoid sinuses at the time of surgery. Follow-up was performed by video endoscopy and by assessment of 2 chronic sinusitis questionnaires at 0, 6, and 24 months postoperatively. The number of lymphocyte subsets (CD3, CD4, CD8), mast cells and eosinophils, and cells expressing IL-4 and IL-5 messenger RNA (mRNA) in all 3 biopsy sites at the time of surgery were compared with the clinical response after surgery.

RESULTS

Seven patients had persistent improvement after surgery, with a decrease in pain, rhinorrhea, or nasal obstruction and a decrease in the need for medication. Eight patients were unchanged or worsened after surgery with disabling rhinorrhea and repeated sinusitis. We found no difference in the number of inflammatory cells, lymphocyte subsets, or IL-4 mRNA-positive cells in the sinus mucosa between responders and nonresponders. However, an increased number of cells expressing IL-5 mRNA was found in the ethmoid sinus at the time of surgery in patients who did not respond to the surgical intervention (P =.007).

CONCLUSION

More than 50% of patients with perennial rhinitis and CRS do not improve after surgery, a response that may be predicted by more cells expressing IL-5 mRNA in the ethmoid sinuses. The increased number of cells expressing IL-5 mRNA may have the potential to be used as a marker for prediction of the response to surgery. The worsening of symptoms in some patients with CRS after sinus surgery could be a result of the disturbance of the anatomy of the sinuses and exposure to the environmental allergens.

Soyfood and isoflavone intake and risk of type 2 diabetes in Vietnamese adults

BACKGROUND/OBJECTIVES

Animal studies have demonstrated that soy isoflavones exert antidiabetic effects. However, evidence regarding the association between soyfood intake, a unique source of isoflavones, and type 2 diabetes remains inconclusive. This study assessed the relationship between habitual intakes of soyfoods and major isoflavones and risk of type 2 diabetes in Vietnamese adults.

SUBJECTS/METHODS

A hospital-based case-control study was conducted in Vietnam during 2013-2015. A total of 599 newly diagnosed diabetic cases (age 40-65 years) and 599 hospital-based controls, frequency matched by age and sex, were recruited in Hanoi, capital city of Vietnam. Information on frequency and quantity of soyfood and isoflavone intake, together with demographics, habitual diet and lifestyle characteristics, was obtained from direct interviews using a validated and reliable questionnaire. Unconditional logistic regression analyses were performed to examine the association between soy variables and type 2 diabetes risk.

RESULTS

Higher intake of total soyfoods was significantly associated with a lower risk of type 2 diabetes; the adjusted odds ratio (OR) for the highest versus the lowest intake was 0.31 (95% confidence interval (CI): 0.21-0.46; P<0.001). An inverse dose-response relationship of similar magnitude was also observed for total isoflavone intake (OR: 0.35; 95% CI: 0.24 to 0.49; P<0.001). In addition, inverse associations of specific soyfoods (soy milk, tofu and mung bean sprout) and major isoflavones (daidzein, genistein and glycitein) with the type 2 diabetes risk were evident.

CONCLUSIONS

Soyfood and isoflavone intake was associated with a lower type 2 diabetes risk in Vietnamese adults.

Endoscopic treatment of distal bile duct stricture from chronic pancreatitis

BACKGROUND

Endoscopic placement of biliary stents is an effective initial treatment for jaundice and cholangitis caused by common bile duct (CBD) strictures secondary to chronic pancreatitis; however, the role of endoscopic treatment for long-term management of these strictures is less clear. In 1992, we designed a protocol of balloon dilatation and stenting for > or =12 months. This study evaluates endoscopic therapy as a definitive long-term treatment for these strictures. We have treated 25 patients with this protocol.

METHODS

All patients had an endoscopic sphincterotomy, balloon dilatation of the stricture, and then placement of a polyethylene stent (7-11.5 F). Stents were exchanged at 3-4-month intervals to avoid the complications of clogging and cholangitis. We were particularly interested in how many patients would achieve resolution of the stricture and tolerate removal of the stent.

RESULTS

The length of the CBD strictures ranged from 8 to 40 mm. Within days of stenting, all patients achieved relief of jaundice and cholestasis. Complications consisted of six episodes of cholangitis and nine episodes of pancreatitis. There were no deaths. Twenty of the 25 patients are now stent-free after an average stenting period of 13 months (range, 3-28). To date, there has been no recurrence of stricture, for a mean of 32 months. Three patients still have stents in place, and two patients required operation--one for persistent stricture and recurrent cholangitis after 8 months of stenting, and one for a mass in the head of the pancreas that was thought to be cancer.

CONCLUSIONS

Our results indicate that these strictures will respond and dilate after a course of stenting in 80% of patients, with an acceptable morbidity. Although these are medium-term results at 32 months, we would expect most recurrences within the 1st year following stent removal. In some cases, stenting is necessary for >12 months. Thus, the data suggest that endoscopic stenting provides definitive treatment in most patients with CBD stricture due to chronic pancreatitis and may be considered a viable alternative to standard surgical bypass.

Variability of neural activation during walking in humans: short heels and big calves

People come in different shapes and sizes. In particular, calf muscle size in humans varies considerably. One possible cause for the different shapes of calf muscles is the inherent difference in neural signals sent to these muscles during walking. In sedentary adults, the variability in neural control of the calf muscles was examined with muscle size, walking kinematics and limb morphometrics. Half the subjects walked while activating their medial gastrocnemius (MG) muscles more strongly than their lateral gastrocnemius (LG) muscles during most walking speeds ('MG-biased'). The other subjects walked while activating their MG and LG muscles nearly equally ('unbiased'). Those who walked with an MG-biased recruitment pattern also had thicker MG muscles and shorter heel lengths, or MG muscle moment arms, than unbiased walkers, but were similar in height, weight, lower limb length, foot length, and exhibited similar walking kinematics. The relatively less plastic skeletal system may drive calf muscle size and motor recruitment patterns of walking in humans.

The Canadian Neuromuscular Disease Registry 2010-2019: A Decade of Facilitating Clinical Research Througha Nationwide, Pan-NeuromuscularDisease Registry

We report the recruitment activities and outcomes of a multi-disease neuromuscular patient registry in Canada. The Canadian Neuromuscular Disease Registry (CNDR) registers individuals across Canada with a confirmed diagnosis of a neuromuscular disease. Diagnosis and contact information are collected across all diseases and detailed prospective data is collected for 5 specific diseases: Amyotrophic Lateral Sclerosis (ALS), Duchenne Muscular Dystrophy (DMD), Myotonic Dystrophy (DM), Limb Girdle Muscular Dystrophy (LGMD), and Spinal Muscular Atrophy (SMA). Since 2010, the CNDR has registered 4306 patients (1154 pediatric and 3148 adult) with 91 different neuromuscular diagnoses and has facilitated 125 projects (73 academic, 3 not-for-profit, 3 government, and 46 commercial) using registry data. In conclusion, the CNDR is an effective and productive pan-neuromuscular registry that has successfully facilitated a substantial number of studies over the past 10 years.

Primary melanocytic schwannoma of cervical sympathetic chain

BACKGROUND

Primary melanocytic schwannoma arising from the cervical sympathetic chain is a rare pigmented nerve sheath tumor. Two cases are presented from an academic medical center. Patients and Methods Patients were initially seen with an enlarging neck mass associated with sympathetic nervous system dysfunction. Radiography demonstrated a mass located posterior to the carotid sheath. Primary therapy consisted of surgical excision and postoperative radiation therapy.

RESULTS

The tumors were found to be melanocytic schwannomas arising from the cervical sympathetic chain. The pathologic characteristics of this neoplasm are reviewed. One patient remained disease free for 12 years after treatment, whereas 1 patient died as a result of local recurrence and distant metastases.

CONCLUSIONS

Melanocytic schwannoma of the cervical sympathetic chain is a rare nerve sheath tumor of the head and neck that may be misdiagnosed as malignant melanoma. The clinical behavior of this neoplasm is variable. Preoperative neurologic findings, anatomic location, electron microscopy, and immunohistochemistry findings help to establish the diagnosis, and electron microscopy may have a role in distinguishing between benign and malignant lesions. Complete surgical excision is the treatment of choice.

Training effects on the regional blood flow response to exercise in myocardial infarcted rats

The regional blood flow (BF) response to submaximal exercise was determined for sedentary and trained myocardial infarcted (MI) rats. Training consisted of treadmill running (10% grade, 30 m/min) for 1 h/day, 5 days/wk for 12-14 wk and produced decreases in resting heart rate and increases in maximal O2 uptake and endurance capacity. BF determined at 2 and 6 min of exercise (via radiolabeled microspheres) demonstrated that trained rats maintained greater BF to organs found in the abdominal region when compared with their sedentary counterparts. BF to the total hindlimb musculature at 2 min of exercise was greater in sedentary rats when compared with their trained counterparts and was the consequence of greater BF to 10 of the 27 muscle or muscle parts investigated. At 6 min of exercise, BF to the total hindlimb musculature was similar between trained and sedentary rats, as BF in 9 of 27 muscles or muscle parts investigated decreased from 2 to 6 min of exercise for the sedentary group. In general, the BF patterns within and among the individual muscles of the hindlimb were different between the two groups. Trained rats tended to maintain greater BF to the predominantly red muscles, whereas the sedentary rats maintained greater BF to the predominantly white muscles at 6 min of exercise. In conclusion, the training-induced changes in BF found in this study are similar to those found previously for normal rats, and they demonstrate that endurance training produces changes in the regional distribution of BF during exercise in MI rats.

Age-related alterations of cardiac tissue microstructure and material properties in Fischer 344 rats

The cardiac aging process is accompanied by global mechanical dysfunction that reflects increased myocardial stiffness. Accordingly, age-related changes in microscopic material properties of myocardium were delineated with high-frequency ultrasound (US) (30 to 44 MHz) tissue characterization methods for aging Fischer 344 rats at 6 (adult), 18 (aged), and 24 (senescent) months of age. The excised lateral wall of the left ventricle of rats (n = 10 per group) was insonified with a 50-MHz acoustic microscope for determination of integrated backscatter, backscatter coefficient and attenuation coefficient. Histological and biochemical analyses for collagen content and cardiac myocyte diameter were performed. Collagen concentration increased progressively with age, with the greatest increments occurring from 6 to 18 months (38.0 +/- 6.3 to 53.0 +/- 7.1 mg/g dry wt), and leveling off at 24 months (60.0 +/- 7.4 mg/g dry wt). Tissue microscopic material properties also changed progressively from 6 to 24 months of age, as determined by US methods: integrated backscatter increased (-44.7 +/- 1.8 vs. -40.8 +/- 1.9 dB, p < 0.05), attenuation increased (47.1 +/- 5.9 to 65.3 +/- 7.8 dB/cm, p < 0.05), and the backscatter coefficient increased (0.73 +/- 0.16 x 10(-5) to 3.76 +/- 1.6 x 10(-5) cm(-1), p < 0.05), from 6 to 24 months of age in each case. Age-related alterations in indices of cardiac microscopic material properties were closely correlated with the changes in cardiac microstructure. Ultrasonic tissue characterization may prove to be a sensitive tool to monitor changes in the cardiac microstructure, such as increased collagen deposition, that occur within age-related diastolic dysfunction.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

BACKGROUND

The clinical application of cardiovascular magnetic resonance (CMR) T2 and T2* mapping is currently limited as ranges for healthy and cardiac diseases are poorly defined. In this meta-analysis we aimed to determine the weighted mean of T2 and T2* mapping values in patients with myocardial infarction (MI), heart transplantation, non-ischemic cardiomyopathies (NICM) and hypertension, and the standardized mean difference (SMD) of each population with healthy controls. Additionally, the variation of mapping outcomes between studies was investigated.

METHODS

The PRISMA guidelines were followed after literature searches on PubMed and Embase. Studies reporting CMR T2 or T2* values measured in patients were included. The SMD was calculated using a random effects model and a meta-regression analysis was performed for populations with sufficient published data.

RESULTS

One hundred fifty-four studies, including 13,804 patient and 4392 control measurements, were included. T2 values were higher in patients with MI, heart transplantation, sarcoidosis, systemic lupus erythematosus, amyloidosis, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and myocarditis (SMD of 2.17, 1.05, 0.87, 1.39, 1.62, 1.95, 1.90 and 1.33, respectively, P <  0.01) compared with controls. T2 values in iron overload patients (SMD = - 0.54, P = 0.30) and Anderson-Fabry disease patients (SMD = 0.52, P = 0.17) did both not differ from controls. T2* values were lower in patients with MI and iron overload (SMD of - 1.99 and - 2.39, respectively, P <  0.01) compared with controls. T2* values in HCM patients (SMD = - 0.61, P = 0.22), DCM patients (SMD = - 0.54, P = 0.06) and hypertension patients (SMD = - 1.46, P = 0.10) did not differ from controls. Multiple CMR acquisition and patient demographic factors were assessed as significant covariates, thereby influencing the mapping outcomes and causing variation between studies.

CONCLUSIONS

The clinical utility of T2 and T2* mapping to distinguish affected myocardium in patients with cardiomyopathies or heart transplantation from healthy myocardium seemed to be confirmed based on this meta-analysis. Nevertheless, variation of mapping values between studies complicates comparison with external values and therefore require local healthy reference values to clinically interpret quantitative values. Furthermore, disease differentiation seems limited, since changes in T2 and T2* values of most cardiomyopathies are similar.

Prevalence of Zika virus neutralizing antibodies in healthy adults in Vietnam during and after the Zika virus epidemic season: a longitudinal population-based survey

Background

Between 2016 and 2019, 265 cases of Zika virus (ZIKV) infection were reported in Vietnam, predominantly in southern Vietnam. In 2016, a case of ZIKV-associated microcephaly was confirmed in the Central Highlands, and several members of the infant’s family were confirmed to be infected with ZIKV. The study aims to determine the level of immunity to ZIKV in the general population of the ZIKV epidemic region.

Methods

A total of 879 serum samples were collected from 801 participants between January 2017 and July 2018, during and after the ZIKV epidemic in Vietnam. The samples were tested for anti-ZIKV immunoglobulin M (IgM) and immunoglobulin G (IgG), and anti-dengue virus (DENV) IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Plaque-reduction neutralization test (PRNT) for ZIKV was performed on all samples, and for DENV on the samples that ZIKV neutralizing antibody positive.

Results

A total of 83 (10.3%) participants had anti-ZIKV IgM. Of the 83, 6 were confirmed to be ZIKV antibodies positive using PRNT and anti-ZIKV IgG ELISA. Of the 718 participants who were anti-ZIKV IgM negative, a further 3 cases were confirmed as positive for antibodies against ZIKV. Of the 9 participants with ZIKV infection, 5 lived in the same village as the infant with ZIKV-associated microcephaly and the other 4 lived in 2 neighboring communes. Repeat samples were collected from the 83 ZIKV IgM positive participants 1.5 years after the first collection. No new cases of ZIKV infection were detected. In addition, 2 of 3 participants with anti-ZIKV NS1 IgG demonstrated a 4- to 8-fold increase in ZIKV neutralizing antibody titer.

Conclusions

ZIKV was present in the area around Krong Buk, with the rate of ZIKV-specific antibodies was 1.1% in the community since at least 2016. While the low levels of circulation together with low seroprevalence suggests a limited outbreak in the region, the results also reflect on low levels of protective immunity to Zika within the population. These results provide a better understanding of the current ZIKV epidemic status in the region and demonstrate a need for implementation of more effective ZIKV infection control measures.

Laryngotracheal reconstruction using a Vitallium alloy miniplate

When stenosis of the larynx and trachea involves loss to anterior support, this is usually corrected by an autograft of costochondral cartilage or of hyoid bone anchored with suture material. This paper describes an alternative technique employing a Vitallium alloy miniplate placed anterior to the airway as a means for providing support. This is placed over a fascial or auricular cartilage graft. Together, they provide a smooth scaffold for mucosal migration. Thirteen patients were treated at Indiana University Medical Center between 1991 and 1993 by means of this technique. Ten of the 13 patients (77%) achieved an adequate airway to allow decannulation. There have been no significant complications related to the use of the miniplate, and specifically, there have been no instances of infection or extrusion. It has been unnecessary to remove any of the miniplates. The Vitallium alloy miniplate offers unique advantages in laryngotracheal reconstruction in that it not only accurately approximates tissues, but it also provides external support to the airway.

Can residents perform transrectal ultrasound-guided prostate biopsy with patient comfort comparable to biopsy performed by attending staff urologists?

Transrectal ultrasound (TRUS)-guided prostate biopsy is a critical diagnostic tool in urology. Residents require adequate training but resident education could have a deleterious effect on patient comfort and morbidity. We compared pain associated with prostate biopsy when performed by staff versus resident urologists in order to determine the impact of resident training. Male patients scheduled to undergo prostate biopsy were assigned to either a staff urologist or a resident as the primary surgeon. All residents were directly assisted by the staff surgeon. The patients were given a visual analogue scale (VAS; 0-100 mm) and were asked to assess the pain associated with each component of prostate biopsy, including probe insertion, anesthetic injection and the biopsies themselves. The mean VAS scores for probe insertion, anesthetic injection and biopsies were 31.0, 30.4 and 30.1, respectively, for patients in the staff cohort and 37.1, 28.9 and 33.6, respectively, for those in the resident cohort. There was a statistically significant difference between staff and resident VAS scores, marked by a higher odds of greater pain with ultrasound probe placement (odds ratio (OR)=1.48, P=0.012) and the biopsies themselves (OR=1.52, P=0.01) in the resident cohort. TRUS biopsy can be performed by adequately trained and supervised resident urologists of all levels, but there is the potential for increased patient pain, particularly with ultrasonic probe insertion and obtaining core biopsies. However, the absolute magnitude of the differences in pain scores between residents and staff was small and may not be clinically meaningful. Such data indicate that urological resident training can be accomplished without compromising patient care and comfort.

Delineation of the extracellular determinants of ultrasonic scattering from elastic arteries

Elastic arteries consist of three primary components: elastin fibers, extracellular collagen matrix and smooth muscle cells. However, the relative contribution of elastin and collagen fibers to overall ultrasonic scattering from an intact arterial wall is poorly understood. To define the principal source of extracellular scattering from the medial layer of elastic arteries, canine ascending aortas (n = 10) were excised, fixed and sectioned for insonification. Subsequently, aortic specimens were restudied after treatment to dissolve all tissue components except extracellular collagen matrix (n = 5) and elastin fibers (n = 5). Histological staining revealed very few elastin fibers and sparse intact collagen in collagen-isolated and elastin-isolated tissues, respectively. Integrated backscatter, attenuation and backscatter coefficients differentiated these two treated tissues. The backscatter coefficient for elastin-isolated tissue demonstrated a fivefold increase over collagen-isolated tissue, suggesting that elastin fibers represent a primary scattering component within elastic arteries, and the collagen fibers may provide a secondary component of scattering.

Ethanol inhibits phosphatidylcholine and phosphatidylethanolamine biosynthesis in human leukemic monocyte-like U937 cells

The effect of ethanol (ETOH) on the incorporation of [14C]oleic acid (18:1) into lipid in human monocyte-like U937 cells was investigated. With increasing time of exposure to ETOH, the percentage of the label distributed into neutral lipid (NL) declined from 35 per cent (3 h) to 10 per cent (24 h) accompanied by increased incorporation into phospholipid (PL). [14C] 18:1 was preferentially incorporated into triglyceride (TG) and phosphatidylcholine (PC), comprising over 65 per cent and 50 per cent of the label associated with NL and PL, respectively. Low concentrations of ETOH (< or = 1.0 per cent; v/v) had no effect. At concentrations greater than 1.5 per cent, there was enhanced incorporation into TG and diacylglycerol (DAG) in a 24-h incubation period, while at 16 h the label in phosphatidylethanolamine (PE) was decreased. The effect of ETOH on the CDP-choline or ethanolamine pathway was examined by monitoring the incorporation of [3H]choline or [14C]ethanolamine into PC or PE, respectively. At low concentrations ETOH had no effect on either choline uptake or the incorporation into PC. Higher concentrations (> or = 1.5 per cent) for 3 and 6 h resulted in a slightly decreased choline uptake, and the reduction (40-50 per cent) of incorporation into PC suggests that the CDP-choline pathway was inhibited. There was a similar inhibition of the incorporation of [14C]ethanolamine into PE. When the cells were incubated for 3 h in the presence of 2 per cent ETOH and with labelled 18:1 and PL-base, the ratios of incorporation (base/18:1) into PC and PE fractions decreased, indicating that the major inhibition lay in blockage of the availability of the base moiety for PL formation. Analysis of the distribution of the label into metabolites revealed that ETOH inhibited the conversion of [14C]ethanolamine into [14C]phosphorylethanolamine. The reduction in incorporation was not due to the enhanced breakdown of base-labelled PL. Our results indicate that ETOH has an inhibitory effect on the CDP-choline or ethanolamine pathway.

Differential effects of unsaturated fatty acids on phospholipid synthesis in human leukemia monocytic U937 cells

The biosynthesis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) in monocyte-like leukemia U937 cells was monitored by adding [3H]choline, [14C]ethanolamine or [14C]glycerol to the culture media; incorporation into phospholipid (PL) increased with time. The effect of unsaturated fatty acids (UFA) on PC and PE synthesis was investigated by pretreating U937 cells for 72h with 10 microM 18:1 (n - 9), 18:2 (n - 6), 18:3 (n - 3), 20:4 (n - 6) and 20:5 (n - 3). The UFA caused no alteration in cell growth, as evidenced by light microscopy and the incorporation of [3H]thymidine and [3H]leucine. Total cellular uptake of radioactive precursors remained unaffected by all the treatments. Pretreatment with 20:5 resulted in approximately 25 per cent reduction in the incorporation of [3H]choline into PL, while no significant effect was detected with the other UFAs. 18:3, 20:4 and 20:5 depressed the incorporation of [14C]ethanolamine into PL by 34 per cent, 28 per cent and 49 per cent respectively. However, there was no redistribution of label with any of the treatments. 18:3, 20:4 and 20:5 also antagonized the stimulatory effect of endotoxin (LPS) on PC and PE synthesis. In addition, the incorporation from [14C]glycerol into PC and PE was reduced by 18:3, 20:4 and 20:5. Although the PL composition of the cells remained essentially unaffected, our study shows that chronic treatment of U937 cells with n - 3 PUFA (20:5) depressed PC and PE synthesis, and 18:3 and 20:4 also caused inhibition of PE synthesis.

Validation of thoracic aortic dimensions on ECG-triggered SSFP as alternative to contrast-enhanced MRA

Objectives

Assessment of thoracic aortic dimensions with non-ECG-triggered contrast-enhanced magnetic resonance angiography (CE-MRA) is accompanied with motion artefacts and requires gadolinium. To avoid both motion artefacts and gadolinium administration, we evaluated the similarity and reproducibility of dimensions measured on ECG-triggered, balanced steady-state free precession (SSFP) MRA as alternative to CE-MRA.

Methods

All patients, with varying medical conditions, referred for thoracic aortic examination between September 2016 and March 2018, who underwent non-ECG-triggered CE-MRA and SSFP-MRA (1.5 T) were retrospectively included (n = 30). Aortic dimensions were measured after double-oblique multiplanar reconstruction by two observers at nine landmarks predefined by literature guidelines. Image quality was scored at the sinus of Valsalva, mid-ascending aorta and mid-descending aorta by semi-automatically assessing the vessel sharpness.

Results

Aortic dimensions showed high agreement between non-ECG-triggered CE-MRA and SSFP-MRA (r = 0.99, p < 0.05) without overestimation or underestimation of aortic dimensions in SSFP-MRA (mean difference, 0.1 mm; limits of agreement, − 1.9 mm and 1.9 mm). Intra- and inter-observer variabilities were significantly smaller with SSFP-MRA for the sinus of Valsalva and sinotubular junction. Image quality of the sinus of Valsalva was significantly better with SSFP-MRA, as fewer images were of impaired quality (3/30) than in CE-MRA (21/30). Reproducibility of dimensions was significantly better in images scored as good quality compared to impaired quality in both sequences.

Conclusions

Thoracic aortic dimensions measured on SSFP-MRA and non-ECG-triggered CE-MRA were similar. As expected, SSFP-MRA showed better reproducibility close to the aortic root because of lesser motion artefacts, making it a feasible non-contrast imaging alternative.

Key Points

• SSFP-MRA provides similar dimensions as non-ECG-triggered CE-MRA.

• Intra- and inter-observer reproducibilities improve for the sinus of Valsalva and sinotubular junction with SSFP-MRA.

• ECG-triggered SSFP-MRA shows better image quality for landmarks close to the aortic root in the absence of cardiac motion.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06963-x) contains supplementary material, which is available to authorized users.

Circulation of influenza B lineages in northern Viet Nam, 2007-2014

INTRODUCTION

Influenza B viruses circulate throughout Viet Nam, and their activities vary by region. There have been two antigenically distinct lineages of influenza B viruses co-circulating in the past 20 years; however, only one lineage is selected as a component of contemporary trivalent seasonal influenza vaccines. To improve the understanding of circulating influenza B lineages and influenza vaccine mismatches, we report the virus lineages circulating in northern Viet Nam over an eight-year period (2007-2014).

METHODS

Lineages of 331 influenza B viruses were characterized by haemagglutination inhibition assay against standard reference ferret (Yamagata) and sheep (Victoria) antisera. Sequence analysis of the haemagglutinin gene was performed in 64 selected influenza B isolates.

RESULTS

The proportion of influenza B lineages changed by year. The Yamagata lineage predominated in 2007, 2008 and 2012; the Victoria lineage predominated in 2009-2014 except 2012. The two lineages showed continuous evolution over time. The Northern Hemisphere's influenza vaccine components were mismatched with the predominant circulating viruses in 2007, 2009 and 2014.

DISCUSSION

The seasonality of influenza B activity is more variable in tropical and subtropical regions than in temperate zones. Our data showed a common co-circulation of both influenza B lineages in northern Viet Nam, and it was difficult to predict which one was the predominant lineage. Quadrivalent influenza vaccines containing both lineages may improve the effectiveness of influenza vaccine programmes in the future.