Morphological features of mitral annular calcification leading to systolic anterior motion of the mitral valve

Background

Systolic anterior motion (SAM) of the mitral valve (MV) can develop after mitral valve repair with placement of an annuloplasty ring. It is occasionally seen in patients with mitral annular calcification (MAC) but mechanisms have not been carefully delineated. Using 2-dimensional echocardiography we explored morphologic parameters which may contribute to SAM in patients with MAC.

Hypothesis

We hypothesized that in cases of MAC where SAM is present there would be anterior displacement of the valve by the posterior annular calcification.

Methods

From our echocardiographic database we identified 20 patients with severe MAC who also had SAM with definite septal contact. Each subject was paired with 2 controls free of MAC and 1 control with severe MAC but no SAM. All controls were matched for age, sex, BSA, and septal wall thickness (±1.5 mm). 2-D echocardiographic measurements were taken from the parasternal long-axis (PLAX), apical 3-chamber and apical 4-chamber views.

Results

MAC+SAM vs MAC no-SAM. Three notable differences were observed: MAC+SAM patients, as compared with MAC no-SAM, had a smaller left ventricular outflow tract (LVOT), longer anterior mitral leaflet, and greater displacement of the MV coaptation point towards the interventricular septum (Figure 1). Median values for these 3 factors were determined using the no-MAC controls; each MAC subject was then scored for number of factors exceeding those values. MAC+SAM patients had a mean score of 2.7 vs 1.1 for MAC no-SAM patients. By combining anterior mitral leaflet length and coaptation point-septal distance as a ratio we could effectively separate MAC+SAM vs MAC no-SAM when >0.9 with one exception (Figure 2). We also observed a smaller anteroposterior annular dimension in the MAC+SAM group.

MAC no-SAM vs no-MAC. Comparing these groups there were no differences in LVOT diameter or coaptation-septal distance; effective anterior mitral leaflet length was smaller in MAC no-SAM subjects vs no-MAC controls while anteroposterior dimension of the annulus was larger.

Conclusions

SAM develops in a subset of patients with severe calcification of the mitral annulus. These patients have a smaller anteroposterior annular dimension, possibly due to severe MAC. Other notable differences characterize MAC patients with SAM from those without. The LVOT is smaller, the effective anterior mitral leaflet length is longer, and the point of leaflet coaptation is displaced towards the septum. Using the ratio of anterior mitral leaflet length/coaptation point-septal distance in this study sample effectively separated those MAC patients with SAM from those without.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Inter-center variation in death or tracheostomy placement in infants with severe bronchopulmonary dysplasia

OBJECTIVE

To estimate the presence and sources of inter-center variation (ICV) in the risk of death or tracheostomy placement (D/T) among infants with severe bronchopulmonary dysplasia (sBPD)Study design:We analyzed the Children's Hospitals Neonatal Database between 2010 and 2013 to identify referred infants born <32 weeks' gestation with sBPD. The association between center and the primary outcome of D/T was analyzed by multivariable modeling. Hypothesized diagnoses/practices were included to determine if these explained any observed ICV in D/T.

RESULTS

D/T occurred in 280 (20%) of 1383 eligible infants from 21 centers. ICV was significant for D/T (range 2-46% by center, P<0.001) and tracheostomy placement (n=187, range 2-37%, P<0.001), but not death (n=93, range 0-19%, P=0.08). This association persisted in multivariable analysis (adjusted center-specific odds ratios for D/T varied 5.5-fold, P=0.009).

CONCLUSIONS

ICV in D/T is apparent among infants with sBPD. These results highlight that the indications for tracheostomy (and subsequent chronic ventilation) remain uncertain.

Racial/ethnic differences in weekend delivery after induction of labor

OBJECTIVE

To determine whether the frequency induction of labor (IOL) varies by day of the week based on maternal race/ethnicity.

STUDY DESIGN

Gravid women in the US from 2007 to 2010 were stratified into <34, 34 to 36, 37 to 38 and ⩾39 weeks. Multivariable analyses estimated the association between weekend delivery, race/ethnicity (categorized as non-Hispanic white, Hispanic white, black and 'other') and their interaction with induction.

RESULT

After 34 weeks, induction was less likely on the weekend (P<0.01) and less likely in black, Hispanic or 'other' women relative to non-Hispanic whites (P<0.01). However, there was a significant positive interaction between race/ethnicity and weekend delivery (P<0.001). During the late preterm gestation, weekend IOL was greater in black women (odds ratio, 1.08).

CONCLUSION

The difference in IOL by race/ethnicity increased with gestational age. This difference was least on the weekends.

Stimulation of synthesis and release of brain-derived neurotropic factor from intestinal smooth muscle cells by substance P and pituitary adenylate cyclase-activating peptide

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a neurotrophin present in the intestine where it participates in survival and growth of enteric neurons, augmentation of enteric circuits, and stimulation of intestinal peristalsis and propulsion. Previous studies largely focused on the role of neural and mucosal BDNF. The expression and release of BDNF from intestinal smooth muscle and the interaction with enteric neuropeptides has not been studied in gut.

METHODS

The expression and secretion of BDNF from smooth muscle cultured from the rabbit intestinal longitudinal muscle layer in response to substance P (SP) and pituitary adenylate cyclase-activating peptide (PACAP) was measured by western blot and enzyme-linked immunosorbent assay. BDNF mRNA was measured by reverse-transcription polymerase chain reaction.

KEY RESULTS

The expression of BNDF protein and mRNA was greater in smooth muscle cells (SMCs) from the longitudinal muscle than from circular muscle layer. PACAP and SP increased the expression of BDNF protein and mRNA in cultured longitudinal SMCs. PACAP and SP also stimulated the secretion of BDNF from cultured longitudinal SMCs. Chelation of intracellular calcium with BAPTA (1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) prevented SP-induced increase in BDNF mRNA and protein expression and SP-induced secretion of BDNF.

CONCLUSIONS & INFERENCES

Neuropeptides known to be present in enteric neurons innervating the longitudinal layer increase the expression of BDNF mRNA and protein in SMCs and stimulate the release of BDNF. Considering the ability of BDNF to enhance smooth muscle contraction, this autocrine loop may partially explain the characteristic hypercontractility of longitudinal muscle in inflammatory bowel disease.

Short-term outcomes after perinatal hypoxic ischemic encephalopathy: a report from the Children's Hospitals Neonatal Consortium HIE focus group

OBJECTIVE

To characterize infants affected with perinatal hypoxic ischemic encephalopathy (HIE) who were referred to regional neonatal intensive care units (NICUs) and their related short-term outcomes.

STUDY DESIGN

This is a descriptive study evaluating the data collected prospectively in the Children's Hospital Neonatal Database, comprised of 27 regional NICUs within their associated children's hospitals. A consecutive sample of 945 referred infants born ⩾36 weeks' gestation with perinatal HIE in the first 3 days of life over approximately 3 years (2010-July 2013) were included. Maternal and infant characteristics are described. Short-term outcomes were evaluated including medical comorbidities, mortality and status of survivors at discharge.

RESULT

High relative frequencies of maternal predisposing conditions, cesarean and operative vaginal deliveries were observed. Low Apgar scores, profound metabolic acidosis, extensive resuscitation in the delivery room, clinical and electroencephalographic (EEG) seizures, abnormal EEG background and brain imaging directly correlated with the severity of HIE. Therapeutic hypothermia was provided to 85% of infants, 15% of whom were classified as having mild HIE. Electrographic seizures were observed in 26% of the infants. Rates of complications and morbidities were similar to those reported in prior clinical trials and overall mortality was 15%.

CONCLUSION

Within this large contemporary cohort of newborns with perinatal HIE, the application of therapeutic hypothermia and associated neurodiagnostic studies appear to have expanded relative to reported clinical trials. Although seizure incidence and mortality were lower compared with those reported in the trials, it is unclear whether this represented improved outcomes or therapeutic drift with the treatment of milder disease.

The Children's Hospitals Neonatal Database: an overview of patient complexity, outcomes and variation in care

The Children's Hospitals Neonatal Consortium is a multicenter collaboration of leaders from 27 regional neonatal intensive care units (NICUs) who partnered with the Children's Hospital Association to develop the Children's Hospitals Neonatal Database (CHND), launched in 2010. The purpose of this report is to provide a first summary of the population of infants cared for in these NICUs, including representative diagnoses and short-term outcomes, as well as to characterize the participating NICUs and institutions. During the first 2 1/2 years of data collection, 40910 infants were eligible. Few were born inside these hospitals (2.8%) and the median gestational age at birth was 36 weeks. Surgical intervention (32%) was common; however, mortality (5.6%) was infrequent. Initial queries into diagnosis-specific inter-center variation in care practices and short-term outcomes, including length of stay, showed striking differences. The CHND provides a contemporary, national benchmark of short-term outcomes for infants with uncommon neonatal illnesses. These data will be valuable in counseling families and for conducting observational studies, clinical trials and collaborative quality improvement initiatives.

Predicting death or tracheostomy placement in infants with severe bronchopulmonary dysplasia

OBJECTIVE

To estimate the risk of death or tracheostomy placement (D/T) in infants with severe bronchopulmonary dysplasia (sBPD) born < 32 weeks' gestation referred to regional neonatal intensive care units.

STUDY DESIGN

We conducted a retrospective cohort study in infants born < 32 weeks' gestation with sBPD in 2010-2011, using the Children's Hospital Neonatal Database. sBPD was defined as the need for FiO2 ⩾ 0.3, nasal cannula support >2 l min(-1) or positive pressure at 36 weeks' post menstrual age. The primary outcome was D/T before discharge. Predictors associated with D/T in bivariable analyses (P < 0.2) were used to develop a multivariable logistic regression equation using 80% of the cohort. This equation was validated in the remaining 20% of infants.

RESULT

Of 793 eligible patients, the mean gestational age was 26 weeks' and the median age at referral was 6.4 weeks. D/T occurred in 20% of infants. Multivariable analysis showed that later gestational age at birth, later age at referral along with pulmonary management as the primary reason for referral, mechanical ventilation at the time of referral, clinically diagnosed pulmonary hypertension, systemic corticosteroids after referral and occurrence of a bloodstream infection after referral were each associated with D/T. The model performed well with validation (area under curve 0.86, goodness-of-fit χ(2), P = 0.66).

CONCLUSION

Seven clinical variables predicted D/T in this large, contemporary cohort with sBPD. These results can be used to inform clinicians who counsel families of affected infants and to assist in the design of future prospective trials.

Therapeutic interventions and short-term outcomes for infants with severe bronchopulmonary dysplasia born at <32 weeks' gestation

OBJECTIVE

To characterize the treatments and short-term outcomes in infants with severe bronchopulmonary dysplasia (sBPD) referred to regional neonatal intensive care units.

STUDY DESIGN

Infants born <32 weeks' gestation with sBPD were identified using the Children's Hospital Neonatal Database. Descriptive outcomes are reported.

RESULT

A total of 867 patients were eligible. On average, infants were born at 26 weeks' gestation and referred 43 days after birth. Infants frequently experienced lung injury (pneumonia: 24.1%; air leak: 9%) and received systemic corticosteroids (61%) and mechanical ventilation (median duration 37 days). Although 91% survived to discharge, the mean post-menstrual age was 47 weeks. Ongoing care such as supplemental oxygen (66%) and tracheostomy (5%) were frequently needed.

CONCLUSION

Referred infants with sBPD sustain multiple insults to lung function and development. Because affected infants have no proven, safe or efficacious therapy and endure an exceptional burden of care even after referral, urgent work is required to observe and improve their outcomes.

Multiple enzyme activities of flavivirus proteins

Dengue viruses (DENV) have 5'-capped RNA genomes of (+) polarity and encode a single polyprotein precursor that is processed into mature viral proteins. NS2B, NS3 and NS5 proteins catalyse/activate enzyme activities that are required for key processes in the virus life cycle. The heterodimeric NS2B/NS3 is a serine protease required for processing. Using a high-throughput protease assay, we screened a small molecule chemical library and identified -200 compounds having > or = 50% inhibition. Moreover, NS3 exhibits RNA-stimulated NTPase, RNA helicase and the 5'-RNA triphosphatase activities. The NTPase and the 5'-RTPase activities of NS3 are stimulated by interaction with NS5. Moreover, the conserved, positively charged motif in DENV-2 NS3, 184RKRK, is required for RNA binding and modulates the RNA-dependent enzyme activities of NS3. To study viral replication, a variety of methods are used such as the in vitro RNA-dependent RNA polymerase assays that utilize lysates from DENV-2-infected mosquito or mammalian cells or the purified NS5 along with exogenous short subgenomic viral RNAs or the replicative intracellular membrane-bound viral RNAs as templates. In addition, a cell-based DENV-2 replicon RNA encoding a luciferase reporter is also used to examine the role of cis-acting elements within the 3' UTR and the RKRK motif in viral replication.

Solid-State Characterization of Buspirone Hydrochloride Polymorphs

The purpose of this study was to characterize Form 1 and Form 2 of buspirone hydrochloride, an anxiolytic medicine. The techniques used for characterization included microscopy (optical, hot stage, and scanning electron microscopy), thermal analysis (differential scanning calorimetry and thermogravimetric analysis), solid-state Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffractometry (XRPD), and Raman spectroscopy. Morphologically, Form 1 and Form 2 consist of plate and columnar crystals, respectively, with good filterability. Thermal analysis showed that the two forms are enantiotropic over the studied temperature range. The FTIR method was used successfully for the quantification of Form 1 in a mixture of Forms 1 and 2. The ratio of a characteristic peak to a reference peak and the chemometric method were used to obtain the calibration curve. The Raman peak shifts showed the difference between the two forms especially for the n-butyl group. The large number of distinguishable XRPD peaks in the region of 5 degrees to 30 degrees 2theta of the two polymorphs demonstrated that XRPD is a useful tool for quantitative and qualitative analysis of polymorphs.