Severely Calcified Pericardium Causing Constrictive Pericarditis

Constrictive pericarditis (CP) is a type of diastolic heart failure caused by an inelastic pericardium that impairs cardiac filling. Diagnosing CP can be challenging, and a variety of imaging techniques may be necessary. We present a unique case of severely calcified pericardium leading to CP.

Contemporary Applications of Machine Learning for Device Therapy in Heart Failure

Despite a better understanding of the underlying pathogenesis of heart failure (HF), pharmacotherapy, surgical, and percutaneous interventions do not prevent disease progression in all patients, and a significant proportion of patients end up requiring advanced therapies. Machine learning (ML) is gaining wider acceptance in cardiovascular medicine because of its ability to incorporate large, complex, and multidimensional data and to potentially facilitate the creation of predictive models not constrained by many of the limitations of traditional statistical approaches. With the coexistence of "big data" and novel advanced analytic techniques using ML, there is ever-increasing research into applying ML in the context of HF with the goal of improving patient outcomes. Through this review, the authors describe the basics of ML and summarize the existing published reports regarding contemporary applications of ML in device therapy for HF while highlighting the limitations to widespread implementation and its future promises.

Percutaneous Aspiration (AngioVac) of a Mitral Valve Vegetation followed by a Transcatheter Mitral Valve-in-Valve Intervention

The AngioVac transcatheter aspiration system (Angiodynamics) is used to percutaneously extract thrombi as well as vegetations typically growing from the right heart. We report a case of a failed mitral stented bioprosthesis due to a large vegetation that was treated successfully with AngioVac evacuation through a transseptal puncture followed by valve-in-valve intervention in the same setting.

Major adverse cardiac events in symptomatic women with non-obstructive CAD on coronary CTA: pooled analysis from PROMISE and SCOT-HEART

The presence of non-obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA) has been associated with the occurrence of major adverse cardiac events (MACE). However, factors associated with the development of MACE in symptomatic women with non-obstructive CAD on coronary CTA have not been fully elucidated. We sought to examine the influence of risk factors and coronary artery calcification on MACE in symptomatic women with non-obstructive CAD on coronary CTA. Women from PROMISE and SCOT-HEART trials with none or non-obstructive CAD on coronary CTA comprised the study cohort. Baseline characteristics and clinical presentation were assessed. Survival analysis using Kaplan-Meier curves was done to compare outcomes stratified by the atherosclerotic cardiovascular disease (ASCVD) risk score and the Agatston score. The primary endpoint was a composite of all-cause mortality, myocardial infarction, and revascularization. 2597 women had non-obstructive CAD or normal coronary CTA, with a median follow-up of 32 months. Compared to women without MACE, women with MACE had lower high-density lipoprotein cholesterol (HDL-C) levels and higher mean ASCVD risk scores. Further, women with non-obstructive CAD and ASCVD ≥ 7.5% had higher risk of MACE than those with ASCVD < 7.5% [3.2% vs. 1.1%, adjusted HR (aHR) of 3.1 (95% CI 1.32, 7.23), P-value 0.009]. The Agatston calcium score, on the other hand, was not independently associated with MACE among this population of symptomatic women. Symptomatic women with non-obstructive CAD on coronary CTA are at higher risk for MACE, with the ASCVD risk score being independently associated with the occurrence of adverse events.

Percutaneous Management of Bioprosthetic Mitral Valve Dehiscence with Combined Valve-in-Valve Replacement and Paravalvular Leak Closure

This case report describes a patient with bioprosthetic mitral valve dehiscence that resulted in severe paravalvular regurgitation and cardiogenic shock. Due to prohibitive surgical risk, valve-in-valve transcatheter mitral valve replacement was attempted but did not reduce the severity of the prosthetic paravalvular leak (PVL) severity. Subsequent percutaneous PVL closure with a ventricular septal defect occluder successfully reduced the PVL severity and led to significant clinical improvement.

Left Atrial Appendage Closure: An Alternative to Anticoagulation for Stroke Prevention in Patients with Kidney Disease

Anticoagulation to reduce thromboembolic stroke risk due to nonvalvular atrial fibrillation in ESKD is associated with increased bleeding. There is an existing debate in ESKD centers around the pros and cons of anticoagulation. We propose percutaneous left atrial appendage occlusion as a third alternative to balance thrombosis and bleeding risks in this high-risk population.

Safety Profile of an Intra-Annular Self-Expanding Transcatheter Aortic Valve and Next-Generation Low-Profile Delivery System

OBJECTIVES

The aim of this study was to characterize the safety profile of an intra-annular self-expanding valve with a next-generation low-profile delivery system (DS).

BACKGROUND

Key design modifications to the FlexNav DS include the addition of a hydrophilic-coated, integrated sheath and stability layer to facilitate gradual, controlled deployment in vessels with diameter ≥5 mm.

METHODS

Patients were pooled from 2 concurrent prospective, multicenter, single-arm studies (FlexNav DS arm of PORTICO IDE [Portico Re-Sheathable Transcatheter Aortic Valve System U.S. IDE Trial] [n = 134] and the FlexNav EU CE Mark Study [n = 46]) for the analysis. The primary endpoint was Valve Academic Research Consortium-2-defined major vascular complications at 30 days. Clinical outcomes and valve performance were assessed through 30 days by an independent clinical events committee and an echocardiography core laboratory, respectively.

RESULTS

One hundred forty high-risk and 40 extreme-risk subjects enrolled between October 15, 2018, and December 10, 2019, from 28 sites in the United States, Australia, and Europe who underwent attempted transfemoral Portico valve implantation were included. The mean age was 85.1 ± 5.6 years, 60% were women, the mean Society of Thoracic Surgeons score was 5.3%, and 96.1% presented with ≥1 frailty factor. Technical device success was 96.7%. At 30 days, the rate of major vascular complications was 5.0%, with 4.4% of complications adjudicated as access site-related (3.3% transcatheter aortic valve replacement DS access site-related). Death (0.6%) and disabling stroke (1.1%) were rare. The rate of new permanent pacemaker implantation was 15.4%. Echocardiography revealed a mean gradient of 7.1 ± 3.2 mm Hg, mean valve area of 1.77 ± 0.41 cm², and a 4.1% rate of moderate paravalvular leak at 30 days.

CONCLUSIONS

Portico valve implantation with the FlexNav DS was associated with an excellent safety profile at 30 days.

Association Between Use of Warfarin for Atrial Fibrillation and Outcomes Among Patients With End-Stage Renal Disease: A Systematic Review and Meta-analysis

IMPORTANCE

Several studies have examined the role of warfarin in preventing strokes in patients with atrial fibrillation and end-stage renal disease; however, the results remain inconclusive.

OBJECTIVE

To assess recently published studies to examine the outcomes of the use of warfarin among patients with atrial fibrillation and end-stage renal disease.

DATA SOURCES

A literature search was performed using the terms warfarin and atrial fibrillation and end-stage renal disease and warfarin and atrial fibrillation and dialysis in the MEDLINE, Embase, and Google Scholar databases from January 1, 2008, to February 28, 2019.

STUDY SELECTION

The studies included were those with patients with end-stage renal disease and atrial fibrillation who were receiving warfarin and with hazard ratios (HRs) of at least 1 primary outcome. The studies excluded were those with a lack of information on outcomes and unreliable 95% CIs of the results.

DATA EXTRACTION AND SYNTHESIS

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed in selecting studies. Collected data were also scrutinized for reliable 95% CIs. Finally, studies were examined for perceived biases, their limitations, and the definitions of the outcomes.

MAIN OUTCOMES AND MEASURES

The HRs and 95% CIs were calculated for the incidence of ischemic stroke, hemorrhagic stroke, major bleeding, and mortality among patients receiving anticoagulants and those not receiving anticoagulants.

RESULTS

Study selection yielded 15 studies with a total of 47 480 patients with atrial fibrillation and end-stage renal disease. Of these patients, 10 445 (22.0%) were taking warfarin. With a mean (SD) follow-up period of 2.6 (1.4) years, warfarin use was associated with no significant change for the risk of ischemic stroke (HR, 0.96; 95% CI, 0.82-1.13), with a significantly higher risk of hemorrhagic stroke (HR, 1.49; 95% CI, 1.03-1.94), with no significant difference in the risk of major bleeding (HR, 1.20; 95% CI, 0.99-1.47), and with no change in overall mortality (HR, 0.95; 95% CI, 0.83-1.09).

CONCLUSIONS AND RELEVANCE

In the studies reviewed, warfarin use appears to have been associated with no change in the incidence of ischemic stroke in patients with atrial fibrillation and end-stage renal disease. However, from the studies reviewed, it does appear to be associated with a significantly higher risk of hemorrhagic stroke, with no significant difference in the risk of major bleeding, and with no change in mortality.

Valve in Valve in Valve

A female patient presented with severe, symptomatic aortic stenosis after distant surgical aortic valve replacement and subsequent transcatheter aortic valve implantation 6 years prior. A 23-mm CoreValve Evolut (Medtronic, Dublin, Ireland) was implanted with excellent symptomatic and hemodynamic results. (Level of Difficulty: Advanced.)

Transient Left Atrial Appendage Inversion During Transcatheter Closure Device Placement

A 72-year-old female patient underwent left atrial appendage closure. During recapture of the occlusion device, transient inversion of the appendageal wall occurred. We describe the mechanism with real-time imaging and share our experience of handling this situation. To the best of our knowledge, this is the first case report of this unique recapture complication.

Frequency of Cholesterol Crystals in Culprit Coronary Artery Aspirate During Acute Myocardial Infarction and Their Relation to Inflammation and Myocardial Injury

Cholesterol crystals (CCs) have been associated with plaque rupture through mechanical injury and inflammation. This study evaluated the presence of CCs during acute myocardial infarction (AMI) and associated myocardial injury, inflammation, and arterial blood flow before and after percutaneous coronary intervention. Patients presenting with AMI (n = 286) had aspiration of culprit coronary artery obstruction. Aspirates were evaluated for crystal content, size, composition, and morphology by scanning electron microscopy, crystallography, and infrared spectroscopy. These were correlated with inflammatory biomarkers, cardiac enzymes, % coronary stenosis, and Thrombolysis in Myocardial Infarction (TIMI) blush and flow grades. Crystals were detected in 254 patients (89%) and confirmed to be cholesterol by spectroscopy. Of 286 patients 240 (84%) had CCs compacted into clusters that were large enough to be measured and analyzed. Moderate to extensive CC content was present in 172 cases (60%). Totally occluded arteries had significantly larger CC clusters than partially occluded arteries (p <0.05). Patients with CC cluster area >12,000 µm² had significantly elevated interleukin-1 beta (IL-1β) levels (p <0.01), were less likely to have TIMI blush grade of 3 (p <0.01), and more likely to have TIMI flow grade of 1 (p <0.01). Patients with recurrent AMI had smaller CC cluster area (p <0.04), lower troponin (p <0.02), and IL-1β levels (p <0.04). Women had smaller CC clusters (p <0.04). Macrophages in the aspirates were found to be attached to CCs. Coronary artery aspirates had extensive deposits of CCs during AMI. In conclusion, presence of large CC clusters was associated with increased inflammation (IL-1β), increased arterial narrowing, and diminished reflow following percutaneous coronary intervention.

Surviving sudden cardiac death secondary to anomalous left coronary artery from the pulmonary artery: a case report and literature review

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is an uncommon type of congenital coronary anomaly. In adults, the clinical picture of ALCAPA varies widely between being asymptomatic, presenting similarly to other heart diseases, or as malignant arrhythmias. Patients who have cardiac arrest are usually young and do not exhibit prior warning symptoms. In this article we describe a case of a 22-year-old healthy male, who experienced cardiac arrest during exertion. He was then diagnosed with ALCAPA, which was surgically corrected.

Pattern and Determinants of Overweight and Obesity Among Future Physicians

Background   Overweight including obesity is a leading cause of present day morbidity and kills more people than underweight. Keeping this background in mind this study had been conducted to establish the pattern of overweight and obesity in the midst of undergraduate medical group and to find out the association of overweight (plump) and obesity with probable hazardous factors. Materials and Methods This descriptive observational study had been conducted among undergraduate medical group for the duration of May to June 2011. Simple random sampling was adopted to select the students under study. A pretested, predesigned self-administered questionnaire was utilized for data collection. Body Mass Index (BMI) was assessed through weight and height and acted as forecaster of heavy figure and or obesity. Overweight and or obesity were analyzed to see the association with certain socio-demographic variables, dietary habits, family history of overweight and or obesity, life style issues, computer use etc. After collection of data, these were analyzed using tabulation, proportion and Chi square through Epi-Info software. Results The study subjects were young adults. The general pattern of overweight (plump) and obesity was 18.0 percent and 4.0 percent respectively. Overweight and or obesity was found significantly high among male students, fast food and soft drinks takers, low takers of fruits and vegetables, alcohol consumers, students with lack of exercise and family history of obesity. Overweight and obesity were not found associated with type of diet (vegetarian or non-vegetarian) and smoking. Conclusion Presence of probable associated factors with regard to overweight (plump) and obesity exists amid medical undergraduate pupils.DOI: http://dx.doi.org/10.3126/nje.v4i1.10134 Nepal Journal of Epidemiology 2014;4 (1): 323-329

Observational assessment and correlates to blood pressure of future physicians of Bengal

INTRODUCTION

Hypertension is a modern day epidemic and growing public health problem. A sizable proportion of world populations suffer from prehypertension or hypertension.

OBJECTIVES

The present study was carried out to detect the prevalence of undiagnosed hypertension among undergraduate medical students and to identify the associated risk factors.

MATERIALS AND METHODS

The study was observational in nature and was done in medical colleges of Bengal. Study tool was a predesigned, pretested, validated, and semi-structured questionnaire containing both open-ended and close-ended questions. Data were collected through self-administration, clinical, and anthropometric examination. The data were then tabulated, analyzed and interpretation was done by using percentage and Chi-square test.

RESULTS

Most of the students (63%) were young adults, predominantly males (67%) and day scholars (71%). Almost one-third of them either suffered from hypertension or at risk of hypertension. Hypertension was found higher among male students. Family history of hypertension or diabetes mellitus was not associated with hypertension. Vegetarian or nonvegetarian diet or extra-salt consumption was also not associated with hypertension. Smoking was shown positively associated with hypertension but alcohol consumption was not. Higher per capita monthly income and overweight or obesity were shown positively associated with hypertension.

CONCLUSION

The overall prevalence of hypertension in this study was 13% and there were positive association of hypertension with multiple socio-demographic factors like age, sex, type of family, per capita monthly income, residence, BMI, smoking, etc.

Impact of drug eluting stent length on outcomes of percutaneous coronary intervention (from the EVENT registry)

In randomized trials, longer drug-eluting stent (DES) length has been associated with adverse clinical events. We used data from the EVENT registry to examine the impact of DES length on outcomes in routine clinical practice. We identified 5,425 unselected consecutive patients from the EVENT registry who had a single vessel treated with DES for nonemergency indications from 2004 through 2007. The association between stented length and short- and long-term outcomes was analyzed in ordinal categories (<15, 15 to 19, 20 to 24, and >24 mm) and as a continuous variable. There were few differences in baseline characteristics across categories. At 1 year, there was a stepwise increase in major adverse cardiac events (composite of death, myocardial infarction [MI], and target lesion revascularization [TLR]) with increasing stent length (8.0%, 10.1%, 11.8%, and 14.8%, p <0.001) and a similar relation with TLR (3.0%, 3.1%, 3.3%, and 5.0%, p = 0.02). After adjusting for demographic, clinical, angiographic, and treatment characteristics, longer stent length remained associated with 1-year major adverse cardiac events (adjusted hazard ratio 1.17 per 10-mm increase stent length) and TLR (hazard ratio 1.20 per 10 mm), but not with stent thrombosis. In conclusion, longer DES length is associated with increased adverse events, predominantly periprocedural MI, but also an increased rate of TLR.

Takotsubo cardiomyopathy associated with titration of duloxetine

Takotsubo cardiomyopathy is characterized by transient multisegmental left ventricular dysfunction, dynamic electrocardiographic changes that mimic acute myocardial infarction, and the absence of obstructive coronary disease. Takotsubo cardiomyopathy has been solidly associated with antecedent emotional and physical stressors that trigger catecholamine surges, which lead to coronary vasospasm or direct myocardial injury. Some medications can also cause catecholamine surges, although this phenomenon is not as well described. Duloxetine is a combined serotonin and norepinephrine reuptake inhibitor (SNRI). The basic goal of SNRIs is to increase catecholamine levels in neuronal tissue. However, the increased catecholamine levels may also affect the cardiovascular system.Herein, we report the case of a 59-year-old woman whose takotsubo cardiomyopathy was temporally associated with the titration of duloxetine. The duloxetine therapy was subsequently discontinued, and the patient's left ventricular function recovered completely 1 month after the index event. The purpose of this report is to alert clinicians to a possible association between SNRI medications and takotsubo cardiomyopathy.

Rapid adoption of drug-eluting stents: clinical practices and outcomes from the early drug-eluting stent era

OBJECTIVES

We sought to evaluate the early drug-eluting stent (DES) era, characterized by widespread device use.

BACKGROUND

Contemporary clinical practice incorporating more selective DES use can only be assessed by understanding the early DES era.

METHODS

All patients receiving DES during the first 3 waves of the Evaluation of Drug Eluting Stents and Ischemic Events (EVENT) Registry (2004-2006) were evaluated. The primary end point was a composite of death, myocardial infarction (MI), and urgent revascularization at discharge and death, MI, or target lesion revascularization (TLR) at 1 year. The composite end point at each time point was compared across waves. Multivariable logistic regression was used for in-hospital outcomes and multivariable Cox regression was used for 1-year end points.

RESULTS

Ninety-two percent of EVENT patients received at least one DES. One third of patients were treated for Acute Coronary Syndromes (ACS) (33.8%), and later waves included lower lesion complexity. Across waves there was more frequent clopidogrel loading, a decrease in heparin and an increase in bivalirudin use (all P < .01). The primary composite end point of in-hospital death, MI or urgent revascularization occurred in 7.2% of patients, and did not differ across waves. Despite remarkably high levels of routine DES usage, the composite end point of death, MI, or TLR at 1 year averaged 13.5% and did not differ across waves. After adjustment, no statistically significant effect of wave on composite bleeding (P = .068) as well as in-hospital TLR (P = .053) was noted. At 1 year, wave was associated with a lower likelihood of TLR in the adjusted model (HR 0.81, P = .03).

CONCLUSIONS

The high-adoption DES era was associated with favorable outcomes, decreasing bleeding rates and changes in antithrombotic approach.

Mechanical versus pharmacologic support for cardiogenic shock

Dynamic left ventricular outflow tract obstruction is a rare cause of cardiogenic shock after an acute myocardial infarction. A case is presented where inotropic support and an intra-aortic balloon pump aggravated the cardiac hemodynamics by this mechanism. The circulatory support provided by Impella 2.5 heart pump, in addition to discontinuation of inotropic support and intra-aortic balloon pump, allowed stabilization and successful percutaneous revascularization.

Stenting for persistent left superior vena cava syndrome

Persistent left superior vena cava is a common congenital anomaly. We present angiographic pictures and hemodynamic tracings from a case of superior vena cava syndrome in a patient with this anomaly. The images depict a challenging percutaneous intervention for the amelioration of the hemodynamic problem, made even more interesting as the patient was a recipient of orthotopic heart transplant.

Transhepatic closure of patent foramen ovale

Transhepatic right heart catheterization is an uncommon procedure for adult interventional cardiologists. We report its successful use for closure of a patent foramen ovale in an elderly patient without femoral vein access. Also described is a novel method of using a vascular plug to achieve hemostasis of the hepatic venous access site.

Acquired coronary cameral fistula--a report of two cases

BACKGROUND

Coronary cameral fistulas (CCF) are an uncommon clinical entity; encountered occasionally during cardiac catheterization. These fistulas most commonly result from congenital abnormalities leading to neovascularization. Other possible etiologies include trauma during surgery or coronary intervention. These fistulas usually terminate directly in a cardiac chamber, most often in the right ventricle.

CASE PRESENTATION

We describe two cases of CCF where a previous coronary angiogram did not show the presence of the abnormality. Cardiac catheterization in our first patient revealed the presence of a fistula from the right coronary artery draining into the right ventricle. A coronary angiogram performed three years prior to this procedure revealed no obstructive coronary artery disease and no evidence of this fistula. In contrast our second case had an aortic valve replacement for severe aortic stenosis. A cardiac catheterization prior to the surgery revealed normal coronaries with no fistula. The patient's subsequent angiogram three years later revealed the acute marginal branch of the right coronary artery draining into the right atrium.

CONCLUSION

Coronary cameral fistula is a rare clinical entity and can be acquired during an individual's lifetime. The puzzling presentation in our first patient is unique because CCF was acquired despite lack of previous instrumentation or trauma to the right coronary artery. The exact mechanism of fistula formation is unknown. However a possible hypothesis is secondary to hypoxia-induced angiogenesis, which has not been described to date.

Ventricular Tachycardia Induced by Biventricular Pacing in Patient with Severe Ischemic Cardiomyopathy

INTRODUCTION

Cardiac resynchronization therapy (CRT) is a new alternative which affords symptomatic improvement in two-thirds of patients who exhibit medically refractory congestive heart failure (CHF) as well as significant prolongation of the QRS duration (>135 msec). As more experience with CRT accrues, unexpected complications of this promising therapy may become apparent. Herein, we describe a patient with severe ischemic cardiomyopathy and refractory CHF who developed incessant ventricular tachycardia (VT) after the initiation of biventricular pacing. The patient is a 75-year-old man who suffered an inferior myocardial infarction 6 years before presenting for CRT. He underwent a three-vessel CABG in 1997. Subsequently, episodes of near syncopal sustained VT developed, for which he received a dual chamber ICD. In 2001 he developed refractory CHF and ECG revealed LBBB with a QRS duration of 195 msec. Shortly after the initiation of biventricular pacing, the patient developed multiple episodes of drug resistant monomorphic VT that could be terminated only transiently by ICD therapies. Ultimately, the only intervention, which proved to be effective in eliminating VT episodes, was inactivation of LV pacing. Despite subsequent therapeutic regimen of sotalol, lidocaine, tocainide, and quinidine all subsequent attempts to reactivate LV pacing resulted in prompt VT recurrence.

CONCLUSION

This case represents a clear example of CRT induced proarrhythmia, which required inactivation of LV pacing for effective acute management. Such an intervention should be considered in CRT patients who exhibit a notable increase in drug refractory VT episodes.

A study on awareness of AIDS among school students and teachers of higher secondary schools in north Calcutta

Higher Secondary School students and their teachers were studied to assess the knowledge about AIDS and attitude towards AIDS patients. Only 13.5% senior school students and 16.2% teachers had clear knowledge regarding AIDS--its general aspects, transmission and prevention. Girls had higher and clear knowledge than boys. 45.8% of girls, 38.8% of boys students and 20.3% of teachers had positive attitudes towards nursing an AIDS case. It is suggested that schools have to device ways to open up more effective communication with students in relation to education on sex and AIDS. Training on AIDS should be emphasized on school teachers who on their turn can teach the students in a correct way about AIDS.

Anchor structure of cell wall surface proteins in Listeria monocytogenes

Many surface proteins of Gram-positive bacteria are anchored to the cell wall by a mechanism requiring a COOH-terminal sorting signal with a conserved LPXTG motif. In Staphylococcus aureus, surface proteins are cleaved between the threonine and the glycine of the LPXTG motif. The carboxyl of threonine is subsequently amide linked to the amino group of the pentaglycine cell wall crossbridge. Here we investigated the anchor structure of surface proteins in Listeria monocytogenes. A methionine and six histidines (MH(6)) were inserted upstream of the LPXTG motif of internalin A (InlA), a cell-wall-anchored surface protein of L. monocytogenes. The engineered protein InlA-MH(6)-Cws was found anchored in the bacterial cell wall. After peptidoglycan digestion with phage endolysin, InlA-MH(6)-Cws was purified by affinity chromatography. COOH-terminal peptides of InlA-MH(6)-Cws were obtained by cyanogen bromide cleavage followed by purification on a nickel-nitriloacetic acid column. Analysis of COOH-terminal peptides with Edman degradation and mass spectrometry revealed an amide linkage between the threonine of the cleaved LPXTG motif and the amino group of the m-diaminopimelic acid crossbridge within the listerial peptidoglycan. These results reveal that the cell wall anchoring of surface proteins in Gram-positive bacteria such as S. aureus and L. monocytogenes occurs by a universal mechanism.

An arginine residue is essential for stretching and binding of the substrate on UDP-glucose-4-epimerase from Escherichia coli. Use of a stacked and quenched uridine nucleotide fluorophore as probe

In the previous paper we demonstrated that uridine-5'-beta-1-(5-sulfonic acid) naphthylamidate (UDPAmNS) is a stacked and quenched fluorophore that shows severalfold enhancement of fluorescence in a stretched conformation. UDPAmNS was found to be a powerful competitive inhibitor (Ki = 0.2 mM) for UDP-glucose-4-epimerase from Escherichia coli. This active site-directed fluorophore assumed a stretched conformation on the enzyme surface, as was evidenced by full enhancement of fluorescence in saturating enzyme concentration. Complete displacement of the fluorophore by UDP suggested it to bind to the substrate binding site of the active site. Analysis of inactivation kinetics in presence of alpha,beta-diones such as phenylglyoxal, cyclohaxanedione, and 2,3-butadione suggested involvement of the essential arginine residue in the overall catalytic process. From spectral analysis, loss of activity could also be directly correlated with modification of only one arginine residue. Protection experiments with UDP showed the arginine residue to be located in the uridyl phosphate binding subsite. Unlike the native enzyme, the modified enzyme failed to show any enhancement of fluorescence with UDPAmNS clearly demonstrating the role of the essential arginine residue in stretching and binding of the substrate. The potential usefulness of such stacked and quenched nucleotide fluorophores has been discussed.

Synthesis and characterization of stacked and quenched uridine nucleotide fluorophores

Intramolecular aromatic interactions in aqueous solution often lead to stacked conformation for model organic molecules. This designing principle was used to develop stacked and folded uridine nucleotide analogs that showed highly quenched fluoroscence in aqueous solution by attaching the fluorophore 1-aminonaphthalene-5-sulfonate (AmNS) to the terminal phosphate via a phosphoramidate bond. Severalfold enhancement of fluorescence could be observed by destacking the molecules in organic solvents, such as isopropanol and dimethylsulfoxide or by enzymatic cleavage of the pyrophosphate bond. Stacking and destacking were confirmed by 1-H NMR spectroscopy. The extent of quenching of the uridine derivatives correlated very well with the extent of stacking. Taking 5-H as the monitor, temperature-variable NMR studies demonstrated the presence of a rapid interconversionary equilibrium between the stacked and open forms for uridine-5'-diphosphoro-beta-1-(5-sulfonic acid) naphthylamidate (UDPAmNS) in aqueous solution. DeltaH was calculated to be -2.3 Kcal/mol, with 43-50% of the population in stacked conformation. Fluorescence lifetime for UDPAmNS in water was determined to be 2.5 ns as against 11 ns in dimethyl sulfoxide or 15 ns for the pyrophosphate adduct of AmNS in water. Such a greatly reduced lifetime for UDPAmNS in water suggests collisional interaction between the pyrimidine and thefluorophore moieties to be responsible for quenching. The potential usefulness of such stacked and quenched nucleotide fluorophores as probes for protein-ligand interaction studies has been briefly discussed.

ADJUNCTIVE USE OF LAMINARIA TENT WITH INTRAMUSCULAR 15(S)15 METHYL PGF2α FOR INDUCTION OF SECOND TRIMESTER ABORTION

The adjunctive use of laminaria tent along with intramuscular 15(S)15 methyl PGF_2α (Prostin 15M, Upjohn) was studied for induction of second trimester abortion. Three hundred and two patients from eight centres were recruited for the study. Ninety-two were primigravidae and 210 were multigravidae. One to three laminaria tents were inserted overnight and they were removed before the start of treatment with 250 µg Prostin 15M administered intramuscularly every two hours till abortion. Of primigravida 81.5% and of the multigravidae 79.5% aborted within 24 hours of treatment. The induction abortion interval in the primigravida was 11.2 hours and in multigravidae it was 12.0 hours. The overall incomplete abortion rate was 31.0%. The pimigravidae had higher mean number of episodes of vomiting (2.5) and diarrhea (2.9) than the multigravidae (1.7 and 1.5, respectively). No other complications or injuries to genital tract were reported.