Novel Insights into the Pathobiology of Pulmonary Hypertension in Heart Failure with Preserved Ejection Fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common cause of pulmonary hypertension (PH) worldwide and is strongly associated with adverse clinical outcomes. The American Heart Association recently highlighted a call to action regarding the distinct lack of evidence-based treatments for PH due to poorly understood pathophysiology of PH attributable to HFpEF (PH-HFpEF). Prior studies have described cardio-physiological mechanisms to explain the development of isolated postcapillary PH (ipc-PH); however, the consequent increased pulmonary vascular (PV) resistance (PVR) may lead to the less understood and more fatal combined pre- and postcapillary PH (cpc-PH). Metabolic disease and inflammatory dysregulation have been suggested to predispose cpc-PH, yet the molecular mechanisms are unknown. Although PH-HFpEF has been studied to partly share vasoactive neurohormonal mediators with primary pulmonary arterial hypertension (PAH), clinical trials that have targeted these pathways have been unsuccessful. The increased mortality of PH-HFpEF patients necessitates further study into viable mechanistic targets involved in disease progression. We aim to summarize the current pathophysiological and clinical understanding of PH-HFpEF, highlight the role of known molecular mechanisms in the progression of PV disease, and introduce a novel concept that lipid metabolism may be attenuating and propagating PH-HFpEF.

The Association Between Myocardial Bridging and Hypertrophic Cardiomyopathy and Their Implications on Percutaneous Coronary Intervention Outcomes: A Retrospective Study

Hypertrophic cardiomyopathy (HCM) is a complex cardiac disorder, often associated with adverse outcomes, including sudden cardiac death. Myocardial bridging (MB), where a coronary artery segment traverses intramurally within the myocardium, complicates coronary blood flow dynamics. This retrospective study investigates the relationship between MB and HCM and their impact on percutaneous coronary intervention (PCI) outcomes. Data from the 2019 National Inpatient Sample (NIS), representing 20% of U.S. hospitalizations, was utilized. Patients with both HCM and MB undergoing PCI were identified and analyzed. The study assessed inpatient outcomes, including mortality, length of stay, hospital cost, and post-PCI complications (atrial fibrillation, acute kidney injury, bleeding, coronary dissection). Patients with HCM and MB exhibited distinct demographics. The study did not find significant associations between HCM/MB and inpatient mortality, length of stay, or hospital cost. However, HCM patients had a higher incidence of atrial fibrillation and acute kidney injury post-PCI (aOR 2.33, 95% CI 1.46 to 3.71, p ≤ 0.001). MB was linked to increased occurrences of acute heart failure (aOR 0.62, 95% CI 0.42-0.92, p = 0.02) and post-PCI bleeding (aOR 4.88, 95% CI 1.17-20.2, p = 0.03). This nationwide study reveals unique demographic profiles for HCM and MB patients. Notably, HCM patients face higher risks of post-PCI complications, including atrial fibrillation and acute kidney injury. These findings provide fresh insights into the MB-HCM relationship and its implications for PCI outcomes. They emphasize the need for tailored interventions and improved patient management in cases involving both HCM and MB.

A profile on the CardioMEMS HF System in the management of patients with early stages of heart failure: an update

INTRODUCTION

Over the past decade, there have been noteworthy advances in the evaluation and treatment of heart failure (HF). Despite improved understanding of this chronic disease, HF is still one of the leading causes of morbidity and mortality in the United States and worldwide. Decompensation and rehospitalization of HF patients remain an integral problem in disease management, with significant economic implications. Remote monitoring systems have been developed to detect HF decompensation early and address it before hospitalization. The CardioMEMS HF system is a wireless pulmonary artery (PA) monitoring system that detects changes in PA pressure and transmits data to the healthcare provider. As changes in PA pressures occur early during HF decompensation, the CardioMEMS HF system allows providers to institute timely changes in HF medical therapies to alter the course of the decompensation. The use of the CardioMEMS HF system has been shown to reduce HF hospitalization and improve quality of life.

AREAS COVERED

This review will focus on the available data supporting the expanded utilization of the CardioMEMS system in patients with HF.

EXPERT OPINION

The CardioMEMS HF system is a relatively safe and cost-effective device that reduces the incidence of HF hospitalization and qualifies as intermediate-to-high value medical care.

Endovascular Transcatheter Aortic Valve Replacement Outcomes in Hypertrophic Cardiomyopathy: Insights from the National Inpatient Sample (2014-2018)

BACKGROUND

Outcomes of patients with hypertrophic cardiomyopathy (HCM) following transcatheter aortic valve replacement (TAVR) remain largely unknown.

OBJECTIVES

This study sought to assess the clinical characteristics and outcomes of HCM patients following TAVR.

METHODS

We queried the National Inpatient Sample from 2014 to 2018 for TAVR hospitalizations with and without HCM, creating a propensity-matched cohort to compare outcomes.

RESULTS

207,880 patients that underwent TAVR during the study period, 810 (0.38%) had coexisting HCM. In the unmatched population, TAVR patients with HCM compared to those without HCM, were more likely to be female, had a higher prevalence of heart failure, obesity, cancer, and history of pacemaker/implantable cardioverter defibrillation, and were more likely to have nonelective and weekend admissions (p for all <0.05). TAVR patients without HCM had higher prevalence of coronary artery disease, prior percutaneous coronary intervention, prior coronary artery bypass grafting, and peripheral arterial disease compared to their counterparts (p for all <0.05). In the propensity-matched cohort, TAVR patients with HCM had significantly higher incidence of in-hospital mortality, acute kidney injury/hemodialysis, bleeding complications, vascular complications, permanent pacemaker requirement, aortic dissection, cardiogenic shock, and mechanical ventilation requirement.

CONCLUSION

Endovascular TAVR in HCM patients is associated with an increased incidence of in-hospital mortality and procedural complications.

De Quervain's tenosynovitis: a non-randomized two-armed study comparing ultrasound-guided steroid injection with surgical release

PURPOSE

Ultrasonography is currently used for both diagnostic and therapeutic purposes in de Quervain's tenosynovitis. There is a dearth of information on how effective an ultrasound-guided (USG) steroid injection is when compared to surgical release of the first extensor compartment. Hence, we performed a non-randomized two-armed comparison study to test our hypothesis that USG guided steroid injection is equally effective as surgery.

METHOD

62 consecutive patients participated in the study with 32 of them selecting the option of USG guided injection (Set A), and the rest undergoing surgical release (Set B). We reviewed them after 3 and 6 weeks and 6 months for functional outcome using DASH, PRWE and VAS scores, recurrence, or any complications. They were further followed if they were symptomatic.

RESULTS

The DASH/PRWE/VAS scores improved at the end of 6 months from 81.7/79.3/6.8 to 1.0/1.7/1.0, respectively for patients undergoing USG guided steroid injection. Similarly, for the patient undergoing surgery, the scores improved from 82.2/81.5/6.7 to 1.7/3.4/1.0, respectively. This was statistically significant in both the groups (p < 0.05) and was comparable to each other. Two patients in Set A came back with recurrence at eight and 10 months and two reported occasional pain on heavy work. Three patients had tenderness and two had numbness in Set B at the scar site.

CONCLUSION

We observed that USG guided steroid injections are comparable to surgical release in terms of pain relief, functional outcome, complications.

Early surgery or conservative management for asymptomatic severe aortic stenosis: Meta-analysis of RECOVERY and AVATAR

The standard practice for management for asymptomatic severe aortic stenosis with a normal left ventricular systolic function is conservative management with a few exceptions. This practice is challenged by two recent randomized controlled trials (RCT). All the prior data is observational. We performed a meta-analysis of these 2 RCTs to determine if early surgical aortic valve replacement in this patient population is beneficial compared with the standard conservative therapy.

Emergency pacemaker implantation in nonagenarians with complete heart block: is single chamber pacing sufficient?

Background

In ambulatory patients with complete heart block and preserved sinus node activity (CHBs), dual chamber pacing confers well-established physiological benefits versus single chamber pacing. There is limited evidence as to whether these benefits extend to very frail patients, especially those over 90 years of age.

Purpose

In nonagenarians presenting with emergent CHBs from 2016–2019, we compared the clinical characteristics of patients selected for single versus dual chamber pacemakers (PPM), and evaluated the symptomatic and prognostic implications of these devices.

Methods

Baseline characteristics were discerned from electronic records, and physiological data extracted from serial PPM interrogations. Frailty was quantified according to the Rockwood clinical frailty scale (1–9). Cause of death was provided by the patients' General Practitioner. Cox proportional hazards analysis (HR, 95% CI) examined associations with all-cause mortality and death from congestive cardiac failure (CCF).

Results

168 consecutive patients were included (44.3% Male, Median age: 91 (2) years) and followed-up for 26.9±14.6 months. 22 patients (13.1%) were implanted with single chamber pacemakers (all programmed VVIR); when compared with patients receiving dual chamber devices, these patients had similar median age (93 (3) versus 91 (2) years, p=0.15) and LV systolic function (LVEF: 49.2% ±9.7 versus 50.7% ±10.1, p=0.71), but were more frail (Rockwood scale: 5.2±1.8 versus 4.3±1.1, p=0.004) and more likely to have severe cognitive impairment (27.3% versus 9.2%, p=0.018). Post implant, patients who received single chamber devices had higher average respiratory rates (21.3±2.4 breaths per minute versus 17.5±2.6 breaths per minute, p=0.002), lower average heart rates (65.5±10.1 bpm versus 71.9±8.6 bpm, p=0.002), and lower daily activity levels (0.57±0.3 hours of activity versus 1.5±1.1 hours of activity, p=0.016) than those with dual chamber devices. Death from CCF was more common in patients receiving single chamber devices (40.9% versus 6.2%, log rank p&lt;0.0001); this association persisted when adjusting for age, frailty and cognitive impairment (adjusted HR: 6.2 (2.2–17.3, p=0.0005). However, in this age group, single chamber pacing was not independently associated with all-cause mortality when compared with dual chamber pacing (adjusted HR: 1.9 (0.95–3.6, p=0.07).

Conclusions

In nonagenarians with CHBs, dual chamber pacing was associated with improved symptomatic outcomes and a reduced risk of death from CCF, but did not affect all-cause mortality when compared with single chamber pacing.

Funding Acknowledgement

Type of funding sources: None.

Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Background

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP).

Purpose

We examined the associations of TSP-related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our centre from 2016–2020.

Methods

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinised to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT.

Results

3,239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP-related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above-median age (OR 2.4 (1.19–4.2), p=0.006) and those undergoing re-do procedures (OR 1.95 (1.29–3.43, p=0.042) were at higher risk of TRCT. Of the operator-dependent variables, choice of transseptal needle (Endrys vs Brockenbrough, p&gt;0.1) or puncture sheath (Swartz vs Mullins vs Agilis vs Vizigo vs Cryosheath, all p&gt;0.1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk (OR 4.42 (2.45–8.2), p=0.001), whilst top quartile operator experience (OR 0.4 (0.17–0.85, p=0.002), transoesophageal echocardiogram (TOE prevalence: 26%, OR 0.51 (0.11–0.94), p=0.023), and use of the SafeSept guidewire (OR 0.22 (0.08–0.62), p=0.001) reduced TRCT risk. An increase in SafeSept wire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R2=0.72, p&lt;0.001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the independent predictors of TRCT were patient age, re-do procedure, operator experience, unsuccessful first pass, TOE-guidance, and use of the SafeSept wire. A novel classification system for the causes of cardiac tamponade is proposed (table 1); this may be of interest to clinical trialists or auditors evaluating patient safety.

Funding Acknowledgement

Type of funding sources: None.

Early versus late discharge after transcatheter aortic valve replacement and readmissions for permanent pacemaker implantation

OBJECTIVE

To examine the rate of readmission for permanent pacemaker (PPM) implantation with early versus late discharge after transcatheter aortic valve replacement (TAVR).

BACKGROUND

There is a current trend toward early discharge after TAVR. However, paucity of data exists on the impact of such practice on readmissions for PPM implantation.

METHODS

The Nationwide Readmission Database 2016-2018 was queried for all hospitalizations where patients underwent TAVR. Hospitalizations were stratified into early (Days 0 and 1) versus late (≥Day 2) discharge groups. Observations in which PPM was required in the index admission were excluded. Multivariable regression analyses involving patient- and hospital-related variables were utilized. The primary outcome was 90-day readmission for PPM implantation.

RESULTS

The final analysis included 68,482 TAVR hospitalizations, 20,261 (29.6%) with early versus 48,221 (70.4%) with late discharge. Early discharge after TAVR increased over the study period (16.2% in 2016 vs. 37.9% in 2018, P_trend  < 0.01). Nevertheless, 90-day readmission for PPM implantation remained stable (1.8% in 2016 vs. 2.0% in 2018, P_trend  = 0.32). The 90-day readmission rate for PPM implantation (2.0% vs. 1.8%; adjusted odds ratio: 1.15; 95% confidence interval: 0.95-1.39; p = 0.15) and median time-to-readmission (5 days [interquartile range, IQR 3-9] vs. 5 days [IQR 3-14], p = 0.92) were similar with early versus late discharge. Similar rates were observed regardless of whether readmission was elective versus not. Early discharge was associated with lower hospitalization cost ($39,990 ± $13,681 vs. $46,750 ± $18,218, p < 0.01) compared with late discharge.

CONCLUSION

In patients who did not require PPM during the index TAVR hospitalization, the rate of readmission for PPM implantation was similar with early versus late discharge.

Transseptal puncture for left atrial ablation: risk factors for cardiac tamponade and a proposed causative classification system

Aims

Cardiac tamponade is a high morbidity complication of transseptal puncture (TSP). We examined the associations of TSP‐related cardiac tamponade (TRCT) for all patients undergoing left atrial ablation at our center from 2016 to 2020.

Methods and Results

Patient and procedural variables were extracted retrospectively. Cases of cardiac tamponade were scrutinized to adjudicate TSP culpability. Adjusted multivariate analysis examined predictors of TRCT. A total of 3239 consecutive TSPs were performed; cardiac tamponade occurred in 51 patients (incidence: 1.6%) and was adjudicated as TSP‐related in 35 (incidence: 1.1%; 68.6% of all tamponades). Patients of above‐median age [odds ratio (OR): 2.4 (1.19–4.2), p = .006] and those undergoing re‐do procedures [OR: 1.95 (1.29–3.43, p = .042] were at higher risk of TRCT. Of the operator‐dependent variables, choice of transseptal needle (Endrys vs. Brockenbrough, p > .1) or puncture sheath (Swartz vs. Mullins vs. Agilis vs. Vizigo vs. Cryosheath, all p > .1) did not predict TRCT. Adjusting for operator, equipment and demographics, failure to cross the septum first pass increased TRCT risk [OR: 4.42 (2.45–8.2), p = .001], whilst top quartile operator experience [OR: 0.4 (0.17–0.85), p = .002], transoesophageal echocardiogram [TOE prevalence: 26%, OR: 0.51 (0.11–0.94), p = .023], and use of the SafeSept transseptal guidewire [OR: 0.22 (0.08–0.62), p = .001] reduced TRCT risk. An increase in transseptal guidewire use over time (2016: 15.6%, 2020: 60.2%) correlated with an annual reduction in TRCT (R² = 0.72, p < .001) and was associated with a relative risk reduction of 70%.

Conclusions

During left atrial ablation, the risk of TRCT was reduced by operator experience, TOE‐guidance, and use of a transseptal guidewire, and was increased by patient age, re‐do procedures, and failure to cross the septum first pass.

The Association of Chronic Kidney Disease With Outcomes Following Percutaneous Left Atrial Appendage Closure

OBJECTIVES

The aim of this study was to investigate the associations of chronic kidney disease (CKD) and end-stage renal disease (ESRD) with in-hospital and short-term outcomes using a large national database representative of contemporary clinical practice.

BACKGROUND

CKD and ESRD are associated with increased risk for stroke and bleeding in patients with atrial fibrillation on oral anticoagulation. Left atrial appendage closure (LAAC) may provide a reasonable alternative for these patients; however, the impact of CKD and ESRD on in-hospital and short-term outcomes following LAAC remain largely unknown.

METHODS

The Nationwide Readmissions Database was used to identify LAAC procedures from 2016 to 2017 in patients with no CKD, CKD (stages I-V), and ESRD. Multivariable logistic regression models were used to assess in-hospital and short-term outcomes. The primary outcome was in-hospital mortality.

RESULTS

Of 21,274 patients who underwent LAAC during the study period, 3,954 (18.6%) had CKD and 571 (2.7%) had ESRD. ESRD was associated with increased risk for in-hospital mortality compared with no CKD (3.3% vs 0.4%; adjusted odds ratio: 6.48; 95% confidence interval: 3.35-12.50; P < 0.001) and CKD (3.3% vs 0.5%; adjusted odds ratio: 11.43; 95% confidence interval: 4.77-27.39; P < 0.001). CKD was associated with increased risk for in-hospital acute kidney injury or hemodialysis and stroke or transient ischemic attack. ESRD and CKD were associated with increased readmissions extending to 90 days compared with no CKD, and ESRD was associated with increased readmissions compared with CKD. There was no difference with respect to other in-hospital outcomes.

CONCLUSIONS

ESRD is associated with higher in-hospital mortality, and CKD is associated with higher rates of stroke or transient ischemic attack in patients undergoing LAAC. Further research is needed to assess the impact of CKD and ESRD on long-term outcomes in these patients.

Bupropion in the treatment of postural orthostatic tachycardia syndrome (POTS): a single-center experience

Postural orthostatic tachycardia syndrome (POTS) is estimated to impact millions of people each year. However, there is no established gold standard for its treatment. Bupropion is a norepinephrine and a dopamine reuptake inhibitor and has been implicated as a potential treatment for POTS. We performed a non-randomized retrospective chart review on 47 patients with POTS with statistical analysis evaluating for significant findings including reduced orthostasis and improvement of symptoms with the use of bupropion. Bupropion was not associated with a statistically significant improvement in orthostatic vitals but there was an overall reduction in reported syncope. While the use of bupropion does not show a statistically significant impact on orthostatic vitals in patients with POTS, it did show a degree of improvement in syncope and as such might be useful in patients with syncope-predominant POTS.

Is balloon-assisted maxillary sinus floor augmentation before dental implant safe and promising? A systematic review and meta-analysis

We aimed to assess the complications of minimally invasive balloon-assisted maxillary sinus floor augmentation, compared with the conventional sinus floor augmentation procedures done before placing a dental implant. A structured question was formulated and an electronic search was conducted in three databases (MEDLINE via PubMed, Google Scholar, and Scopus). A separate search of gray literature and a hand search for missing articles were also conducted. Apart from animal studies, in-vitro studies, and case reports, all other types of studies where maxillary sinus floor augmentation was done using a balloon were considered for review. Our review was registered in International Prospective Registration of Systematic Reviews (PROSPERO) under number CRD42018086770. Our search produced 73 articles. However, only eight articles were found eligible to be included in our review (seven case series and one case-control study). Quality check was done using Methodological Index for Non-Randomized Studies (MINORS). Results suggest that balloon-assisted augmentation is associated with low rates of membrane tears (9 out of 272 sinus augmentation attempts), and high follow-up bone gain levels (mean 212.91%, 95% confidence interval 158.07%-267.75%, I2 = 97.62%). Balloon-assisted augmentation seems to be safe. More clinical trials are needed to assess the advantages and disadvantages of balloon-assisted maxillary sinus floor augmentation compared with other procedures.

Long-Term Postoperative Complication of the Cabrol Procedure Presenting as Recurrent Anterior ST-Segment Elevation Myocardial Infarction

•

Development of fistulae between the aneurysm sac and aortic graft can be a potential source of thrombi in patients treated with surgical aortic root replacement.

•

Transesophageal echocardiography is an effective tool to assess post-operative complications of the Cabrol procedure.

•

Post-operative complications of the Cabrol procedure can have a very delayed initial presentation.

Evaluating cortico-cancellous ratio using virtual implant planning and its relation with immediate and long-term stability of a dental implant- A CBCT-assisted prospective observational clinical study

BACKGROUND

Primary and long-term implant stabilities are crucial in predicting the success of dental implants. We aimed to evaluate corticocancellous ratio (CCR) around virtual implant using cone beam computed tomography (CT) and assess its relationship with immediate and long-term stability of the implants placed.

MATERIALS AND METHODS

A total of 135 image records of posterior mandibular implant sites planned for dental implant were included in our study. CCR was calculated using CT images and implants were placed after stent preparation. Implant stability was calculated immediately, 4 months later, and 2 years later.

RESULTS

Pearson's correlation test showed a significant correlation (P and lt; 0.001) between CCR and implant stability. ANOVA and post-hoc Tukey tests showed a significant difference in implant stability between groups with different CCRs at all follow-up timepoints. No significant difference was found between mean implant stability quotient values for low CCR at 2-year follow-up and high CCR immediately after implant placement.

CONCLUSIONS

Implant stability is improved with greater CCR. Cortical bone seems to be crucial factor for immediate and long-term stability of a dental implant. Virtual planning using CT can assess implant stability. Further histological studies are required to confirm the relation between CCR and implant stability. The escalating demand of the implant treatment in the dental practice necessitates measuring the several predictors of procedure success. This study introduces a novel predictor (CCR) around virtual implant for detecting the immediate and long-term stability of a dental implant.

GABA Transaminase Deficiency With Survival Into Adulthood

γ-Aminobutyric acid (GABA)-transaminase deficiency is an ultra-rare disorder of GABA metabolism that was described for decades as an early-onset epileptic encephalopathy plus movement disorder and hypersomnolence with mortality in early childhood. We report 2 affected siblings in adolescence and adulthood, both with profound developmental impairment, intractable epilepsy, movement disorder, and behavioral fluctuations. This considerably expands the phenotype and longevity of this inherited neurotransmitter disease.

Bioelectrical impedance analysis (BIA)-derived phase angle (PA) is a practical aid to nutritional assessment in hospital in-patients

BACKGROUND

Nutritional status can be difficult to assess. Bioelectrical impedance analysis (BIA)-derived phase angle (PA), and the plasma markers citrulline and transthyretin (pre-albumin) have the potential to assist, but the protocol of fasting and resting for BIA renders the investigation impractical for routine use, especially so in populations at high risk of malnutrition.

AIMS

1 To clarify whether starving and resting are necessary for reliable measurement of PA. 2 To identify whether PA, citrulline and transthyretin correlate with nutritional status.

METHODS

Eighty consenting adult in-patients were recruited. Nutritional status was determined by subjective global assessment (SGA) used as gold standard. The Malnutrition Universal Screening Tool (MUST) was used and anthropometric measurements were performed. Serum was analysed for citrulline and transthyretin. PA was measured using Bodystat 4000. The PA was considered to define malnutrition when lower than reference ranges for sex and age, and severe malnutrition if more than 2 integers below the lower limit. Anthropometric measurements were categorised according to WHO reference centiles. Ordinal logistic regression estimated the strength of association of PA, citrulline and transthyretin with SGA. PA values in the different metabolic states were compared using paired t tests.

RESULTS

All 80 subjects completed the BIA and the nutritional assessments in the 3 different states; 14 declined to provide blood samples for the biochemical assays. Malnutrition was identified in 32 cases, severe malnutrition in 14 cases, the remaining 34 cases were deemed not to be malnourished. PA was strongly inversely associated with SGA (Odds Ratio [OR] per unit increase = 0.21, CI 0.12-0.37, p < 0.001). PA was not influenced by exercise (p = 0.134) or food intake (p = 0.184). Transthyretin was inversely associated with malnourished/severely malnourished states (OR = 0.98, 95% CI 0.97-0.99, p = 0.001), but had poorer predictive values than PA. There was no significant association between citrulline concentration and SGA (OR = 1.01, 95% CI 0.99-1.04, p = 0.348).

CONCLUSIONS

The BIA-derived PA reliably identifies malnutrition. It is strongly associated with SGA but requires less skill and experience, and out-performs circulating transthyretin, rendering it a promising and less operator-dependent tool for assessing nutritional status in hospital patients. Our novel demonstration that fasting and bed-rest are unnecessary consolidates that position.

Advanced diffusion imaging for assessing normal white matter development in neonates and characterizing aberrant development in congenital heart disease

Background

Elucidating developmental trajectories of white matter (WM) microstructure is critically important for understanding normal development and regional vulnerabilities in several brain disorders. Diffusion Weighted Imaging (DWI) is currently the method of choice for in-vivo white matter assessment. A majority of neonatal studies use the standard Diffusion Tensor Imaging (DTI) model although more advanced models such as the Neurite Orientation Dispersion and Density Imaging (NODDI) model and the Gaussian Mixture Model (GMM) have been used in adult population. In this study, we compare the ability of these three diffusion models to detect regional white matter maturation in typically developing control (TDC) neonates and regional abnormalities in neonates with congenital heart disease (CHD).

Methods

Multiple b-value diffusion Magnetic Resonance Imaging (dMRI) data were acquired from TDC neonates (N = 16) at 38 to 47 gestational weeks (GW) and CHD neonates (N = 19) aged 37 weeks to 41 weeks. Measures calculated from the diffusion signal included not only Mean Diffusivity (MD) and Fractional Anisotropy (FA) derived from the standard DTI model, but also three advanced diffusion measures, namely, the fiber Orientation Dispersion Index (ODI), the isotropic volume fraction (Viso), and the intracellular volume fraction (Vic) derived from the NODDI model. Further, we used two novel measures from a non-parametric GMM, namely the Return-to-Origin Probability (RTOP) and Return-to-Axis Probability (RTAP), which are sensitive to axonal/cellular volume and density respectively. Using atlas-based registration, 22 white matter regions (6 projection, 4 association, and 1 callosal pathways bilaterally in each hemisphere) were selected and the mean value of all 7 measures were calculated in each region. These values were used as dependent variables, with GW as the independent variable in a linear regression model. Finally, we compared CHD and TDC groups on these measures in each ROI after removing age-related trends from both the groups.

Results

Linear analysis in the TDC population revealed significant correlations with GW (age) in 12 projection pathways for MD, Vic, RTAP, and 11 pathways for RTOP. Several association pathways were also significantly correlated with GW for MD, Vic, RTAP, and RTOP. The right callosal pathway was significantly correlated with GW for Vic. Consistent with the pathophysiology of altered development in CHD, diffusion measures demonstrated differences in the association pathways involved in language systems, namely the Uncinate Fasciculus (UF), the Inferior Fronto-occipital Fasciculus (IFOF), and the Superior Longitudinal Fasciculus (SLF). Overall, the group comparison between CHD and TDC revealed lower FA, Vic, RTAP, and RTOP for CHD bilaterally in the a) UF, b) Corpus Callosum (CC), and c) Superior Fronto-Occipital Fasciculus (SFOF). Moreover, FA was lower for CHD in the a) left SLF, b) bilateral Anterior Corona Radiata (ACR) and left Retrolenticular part of the Internal Capsule (RIC). Vic was also lower for CHD in the left Posterior Limb of the Internal Capsule (PLIC). ODI was higher for CHD in the left CC. RTAP was lower for CHD in the left IFOF, while RTOP was lower in CHD in the: a) left ACR, b) left IFOF and c) right Anterior Limb of the Internal Capsule (ALIC).

Conclusion

In this study, all three methods revealed the expected changes in the WM regions during the early postnatal weeks; however, GMM outperformed DTI and NODDI as it showed significantly larger effect sizes while detecting differences between the TDC and CHD neonates. Future studies based on a larger sample are needed to confirm these results and to explore clinical correlates.

Probing the highly transparent and conducting SnOx/Au/SnOx structure for futuristic TCO applications

A SnO_x/Au/SnO_x transparent conductive oxide (TCO) multilayered film was fabricated with a total thickness of 75 nm using both e-beam and thermal evaporation techniques.

PD-1-dependent restoration of self-tolerance in the NOD mouse model of diabetes after transient anti-TCRβ mAb therapy

AIMS/HYPOTHESIS

T cells play a major role in the pathogenesis of type 1 diabetes, and there is great interest in developing curative immunotherapies targeting these cells. In this study, a monoclonal antibody (mAb) targeting the T cell receptor β-chain (TCRβ) was investigated for its ability to prevent and reverse disease in mouse models of diabetes.

METHODS

RIP-OVA(hi) (C57BL/6-Tg(Ins2-OVA)59Wehi/WehiJ) mice adoptively transferred with ovalbumin-specific T cells (an induced model of diabetes) and NOD mice (a spontaneous model of diabetes) were used to test anti-TCRβ mAb therapy as a means of preventing and reversing type 1 diabetes.

RESULTS

A single dose of anti-TCRβ completely prevented disease in RIP-OVA(hi) mice without inducing the release of inflammatory cytokines. Transient anti-TCRβ therapy prevented diabetes in 90% of NOD mice and reversed the disease after its onset in 73% of NOD mice. Long after the remission of type 1 diabetes, the anti-TCRβ treated mice were able to reject BALB/c skin allografts with normal kinetics while maintaining normoglycaemia. Treatment did not cause significant reductions in lymphocyte numbers in the spleen or pancreatic lymph nodes, but did result in a decreased percentage of chemokine receptor 9 (CCR9) positive, CD8(+) T cells. Notably, anti-TCRβ therapy increased the expression of programmed death 1 (PD-1) on the surface of the T cells; PD-1 expression is important for maintaining anti-TCRβ-induced self-tolerance, as type 1 diabetes recurs in mice following a blockade of PD-1 signalling.

CONCLUSIONS/INTERPRETATION

Anti-TCRβ mAb is a safe and effective immunotherapy that results in reduced numbers of CCR9(+) T cells, an increased expression of PD-1 on T cells and the restoration of self-tolerance in NOD mice.

Diffraction of orbital angular momentum carrying optical beams by a circular aperture

Far field diffraction of Laguerre-Gauss vortex (LGV) beams of different angular momentum index by a circular aperture placed at different locations with respect to incident beam waist is studied experimentally. The experiments reveal a surprisingly simple structure for the diffraction pattern and its dependence on the orbital angular momentum index of the incident beam when the aperture size is small compared to the beam radius.

Blended distance education program for junior doctors working in rural hospitals in India

CONTEXT

Distance learning, supported with supervised clinical work, has been successful in helping doctors located in remote rural areas to practice effectively. Graduates of Christian Medical College (CMC), Vellore, India, have a 2-year service obligation to work in small hospitals mainly located in rural areas. The Fellowship in Secondary Hospital Medicine (FSHM) program is a year-long blended on-site and distance learning program, designed by CMC to support and provide education opportunities for its recent graduates working in small hospitals in rural areas. The FSHM program was designed to help junior doctors develop the knowledge and skills to practice effectively in rural hospitals.

ISSUES

The FSHM program consists of 15 paper-based distance learning modules focused on helping to develop knowledge to practice in rural hospitals; three contact sessions at CMC, which focused on developing the necessary skills; project work focused on improving local health services; and networking between peers and with faculty. Two years after implementation of the FSHM program in 2007, the vast majority of students (81%) and faculty (80%) rated the distance learning modules as very good or excellent in helping students develop the knowledge to practice in secondary hospitals. Also, most of the students (88%) and faculty (87%) rated the contact sessions as good or very good in helping students to apply what they had learned in secondary hospitals. Focus group discussions revealed that all of the program participants recognized that the distance learning modules and contact sessions helped them in providing patient care in rural hospitals.

LESSONS LEARNED

Well-designed distance learning modules, supported with contact sessions by medical school faculty members, help junior doctors to practice effectively in rural hospitals and reduce their isolation.

Nucleic acid-mediated cleavage of M1 gene of influenza A virus is significantly augmented by antisense molecules targeted to hybridize close to the cleavage site

Influenza A virus genome segment 7 encodes protein M1, which is the matrix protein playing crucial role in the virus life cycle. Any antiviral strategy that aims at reducing, in particular, the expression of this genome segment should, in principle, reduce the infectivity of the virus. We developed a specific antiviral approach at the molecular level and designed several novel 10-23 DNAzymes (Dz) and hammerhead ribozymes (Rz), specifically targeted to cleave at the conserved domains of the influenza virus M1 RNA. We sought to use antisense molecules with the hope that it will facilitate the ribozyme-mediated cleavage. We observed that the Mg(2+)-dependent sequence-specific cleavage of M1 RNA was achieved by both the Dz and Rz in a dose-dependent manner. This combination of catalytic Dz and Rz with antisense molecules, in principle, resulted in more effective gene suppression, inhibited the whole virus replication in host cell, and thus could be exploited for therapeutic purposes.

A networking approach to reduce academic and social isolation for junior doctors working in rural hospitals in India

INTRODUCTION

Graduates from Christian Medical College (CMC) Vellore face many challenges while doing their service obligation in smaller hospitals, including academic and social isolation. To overcome these challenges, CMC aspired through its Fellowship in Secondary Hospital Medicine (FSHM), a 1-year blended on-site and distance-learning program, to provide academic and social support through networking for junior doctors working in rural areas. The purpose of this paper is to report the evaluation of the networking components of the FSHM program, with a focus on whether it succeeded in providing academic and social support for these junior doctors.

METHODS

A mixed method evaluation was done using written surveys for students and faculty and telephone interviews for students. Evidence for validity was gathered for the written survey. Criteria for validity were also applied for the qualitative data analysis.

RESULTS

The major strengths of networking with faculty and peers identified were that it provided social support,, academic support through discussion about patient management problems and a variety of cases seen in the hospital, guidance on projects and reminders about deadlines. Recommendations for improvement included use of videoconferencing and Yahoo Groups.

CONCLUSION

It is useful to incorporate networking into distance-learning educational programs for providing support to junior doctors working in rural hospitals.

An effective integrated learning programme in the first year of the medical course

BACKGROUND

An integrated approach to teaching medical subjects is an effective educational strategy. Yet, this has not become popular in medical colleges in India. We describe an integrated learning programme to teach the gastrointestinal system in the first year of the medical course.

METHODS

The integrated learning programme was conducted for 3 years (2003-2005). It incorporated elements of problem-based learning, early clinical exposure, lectures and small group laboratory work. Student assessment was formative (for problem-based learning sessions) and summative (using problem-based learning and knowledge tests). Evaluation of the programme was based on feedback from the students and faculty members.

RESULTS

Ninety-six per cent of the students obtained more than 60% marks in the problem-based learning test. The mean (SD) score in the knowledge test was 62 (0.89)%. The majority of students received satisfactory and more than satisfactory grades for their performance in the problem-based learning sessions. The feedback from faculty members and students was positive, which highlighted benefits such as integrated learning of the basic sciences, their application to clinical cases and active student learning. The challenges encountered included the higher input required from faculty members. Most of the faculty members and students recommended that the integrated programme should be continued and extended to other parts of the curriculum.

CONCLUSION

An integrated learning programme is feasible within a conventional medical curriculum of an Indian medical college.

Serial bronchoalveolar lavage of preterm infants is not associated with chest radiological changes

Concern has been raised that serial non-bronchoscopic bronchoalveolar lavage (NB-BAL) may constantly remove surfactant which may result in localised radiological changes. Radiological scores for the lavaged right lower lobe (RLL) were compared with (1) the scores for the unlavaged contra-lateral left lower lobe (LLL) in the NB-BAL group and (2) with the scores of the RLL of control infants not undergoing any formal lavage procedure. NB-BAL was performed daily for 2 weeks and twice weekly thereafter until 28 days of age or until extubation. Two paediatric radiologists obtained chest radiological scores at 1 (pre-lavage radiograph), 7 and 28 days of age. A total of 28 infants in the NB-BAL group (mean birth weight 1350 g and gestation 28.6 weeks) and 26 control infants (1450 g, 29.9 weeks) were studied. Radiological scores for the lavaged RLL and the unlavaged LLL in the NB-BAL group were similar at all time points studied. Although the RLL score in the NB-BAL group was higher on day 1 prior to NB-BAL when compared to control infants (3.2 versus 2.5, P<0.05), the subsequent scores at day 7 (2.6 versus 2.9) and 28 (2.7 versus 2.8) were similar in both groups. No differences were found between the two groups for any clinical parameter including ventilation, oxygen dependency, retinopathy of prematurity or intracranial haemorrhage.

CONCLUSION

repeated non-bronchoscopic bronchoalveolar lavage in newborn infants does not appear to be associated with radiological changes suggesting that surfactant is not constantly removed.

Entanglement, interference, and measurement in a degenerate parametric oscillator

Quantum dynamical equations of motion for homodyne detection of the degenerate optical parametric oscillator are solved exactly. Nonclassical photon statistics are shown to be a consequence of interference of probability amplitudes, entanglement of photon pairs from such an oscillator, and the role of measurement in quantum evolution.

Investigations in the transition metal catalyzed aziridination of olefins, amination, and other insertion reactions with Bromamine-T as the source of nitrene

Investigations into the transition metal catalyzed aziridination of olefins with Bromamine-T as a new source of nitrene is presented in this account. Comparison of Chloramine-T and Bromamine-T in this reaction indicates that the latter is superior as the source of nitrene. Systematic study with several transition metal based catalysts suggests that Cu-halides are the best catalysts. A first report of aziridination under microwave and ultrasound irradiation conditions is also presented. Copper-catalyzed aziridination of methyl cinnamate with Bromamine-T did not proceed at ambient temperature but was effected smoothly under ultrasound irradiation to furnish trans-aziridine selectively, while under microwave irradiation, a mixture of cis and trans isomers, was obtained. It has been demonstrated that aziridination of olefins proceeds smoothly with inexpensive bleaching powder. Preliminary results of Rh-catalyzed benzylic insertion reactions with Bromamine-T are included in this account.

Suppression of tumorigenicity in human ovarian cancer cell lines is controlled by a 2 cM fragment in chromosomal region 6q24-q25

Multiple distinct regions of chromosome 6 are frequently affected by losses of heterozygosity in primary human ovarian carcinomas. We introduced a normal human chromosome 6 into HEY and SKOV-3 ovarian carcinoma cell lines using microcell-mediated chromosome transfer techniques to further investigate the role of this chromosome in ovarian tumorigenesis. The exogenous chromosome was stably propagated in the recipient cells based on fluorescence in situ hybridization (FISH) analyses with a chromosome 6 painting probe. The tumorigenicity of HEY and SKOV-3 cells was completely suppressed after transfer of chromosome 6, but not after transfer of a chromosome 11q13-qter fragment used as control. Using 46 polymorphic microsatellite markers, the region bounded by D6S1649 and D6S1564 was found to be commonly deleted in HEY: chromosome 6 tumorigenic revertant clones. The boundaries of the commonly deleted region could be further narrowed down to a 2 cM (based on the Whitehead genetic map) or 0.36 megabase (based on gdb mapping data) region between D6S1637 and D6S1564 after transferring the exogenous chromosome from revertants into mouse L cells and performing allelic deletion mapping studies against this mouse background. We conclude that this region contains a tumor suppressor gene important for the control of ovarian tumor development.

Photothermal lensing detection: theory and experiment

Photothermal lensing signal shapes are experimentally investigated and compared with those predicted theoretically in our earlier paper. The investigation included flowing and stationary media and pulsed and cw excitations. Good qualitative agreement between theory and experiment is found. Since the lensing signal is almost always accompanied by a deflection signal, the influence of the deflection signal on the detection of lensing signal is investigated. For a perfectly aligned detection geometry the influence of the deflection signal on the lensing signal is negligible, but in the presence of misalignments a significant amount of deflection signal could be superimposed on the lensing signal. The effect of lensing on the deflection signal is also been considered. The effect of the finite size of the probe beam on the lensing signals is also investigated.

Clinical dysautonomia in diabetes mellitus--a study with seven autonomic reflex function tests

Thirty-eight patients of NIDDM, 12 of IDDM and 10 healthy age matched controls were subjected to seven standardised autonomic reflex function tests. A scoring criteria was utilised for diagnosing and grading the severity of dysautonomia. Eight patients of IDDM and 24 of NIDDM had dysautonomia. One-third of the patients in each group had grade IV autonomic dysfunction. Severity of autonomic dysfunction was directly related to the duration of disease in NIDDM whereas in IDDM this relation was not seen. Peripheral neuropathy was almost always associated with dysautonomia in NIDDM. On the contrary, in IDDM dysautonomia was independent of peripheral neuropathy. Charcot's arthopathy, dysphagia, constipation and nocturnal diarrhea were always associated with evidence of dysautonomia. Other symptoms viz. gustatory sweating, postural dizziness and impotence did not necessarily indicate dysautonomia.

Theory of photothermal spectroscopy in an optically dense fluid

The theory of photothermal spectroscopy in an optically dense fluid is presented. The general case is considered in which the fluid may be flowing or stationary, and the excitation could be cw (modulated or unmodulated) or pulsed (arbitrary pulse length). All three detection schemes, deflection, phase shift, and lensing, are considered. This is the most complete theory of photothermal spectroscopy in fluids to date.

Toxoplasmosis of the spinal cord in a patient with AIDS: case report and review

We present the case of a patient whose acute myelopathy almost completely resolved with empirical therapy for toxoplasmosis, and we review thirteen previously reported cases of myelopathy thought to have been caused by Toxoplasma gondii in patients with AIDS. The most common symptoms and abnormal physical findings were motor loss (usually paraparesis), bilateral sensory loss, urinary bladder dysfunction, and local pain. The majority of patients had magnetic resonance images that showed abnormalities of the spinal cord and brain in association with positive serology for Toxoplasma. Therapy for toxoplasmosis, when administered soon after the onset of symptoms, has resulted in clinical and radiographic improvement in the conditions of patients with toxoplasmosis.