N-Containing Carbon-Coated β-Si3 N4 Enhances Si Anodes for High-Performance Li-Ion Batteries

The lithiation/delithiation properties of α-Si₃ N₄ and β-Si₃ N₄ are compared and the carbon coating effects are examined. Then, β-Si₃ N₄ at various fractions is used as the secondary phase in a Si anode to modify the electrode properties. The incorporated β-Si₃ N₄ decreases the crystal size of Si and introduces a new NSiO species at the β-Si₃ N₄ /Si interface. The nitrogen from the milled β-Si₃ N₄ diffuses into the surface carbon coating during the carbonization heat treatment, forming pyrrolic nitrogen and CNO species. The synergistic effects of combining β-Si₃ N₄ and Si phases on the specific capacity are confirmed. The operando X-ray diffraction and X-ray photoelectron spectroscopy data indicate that β-Si₃ N₄ is partially consumed during lithiation to form a favorable Li₃ N species at the electrode. However, the crystalline structure of the hexagonal β-Si₃ N₄ is preserved after prolonged cycling, which prevents electrode agglomeration and performance deterioration. The carbon-coated β-Si₃ N₄ /Si composite anode shows specific capacities of 1068 and 480 mAh g^-1 at 0.2 and 5 A g^-1 , respectively. A full cell consisting of the carbon-coated β-Si₃ N₄ /Si anode and a LiNi_0.8 Co_0.1 Mn_0.1 O₂ cathode is constructed and its properties are evaluated. The potential of the proposed composite anodes for Li-ion battery applications is demonstrated.

Suppression of Dehydrofluorination Reactions of a Li0.33La0.557TiO3-Nanofiber-Dispersed Poly(vinylidene fluoride-co-hexafluoropropylene) Electrolyte for Quasi-Solid-State Lithium-Metal Batteries by a Fluorine-Rich Succinonitrile Interlayer

Solid-state lithium-metal batteries have great potential to simultaneously achieve high safety and high energy density for energy storage. However, the low ionic conductivity of the solid electrolyte and large electrode/electrolyte interfacial impedance are bottlenecks. A composite solid electrolyte (CSE) that integrates electrospun Li_0.33La_0.557TiO₃ (LLTO) nanofibers, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is fabricated in this work. The effects of the LLTO filler fraction and morphology (spherical vs fibrous) on CSE conductivity are examined. Additionally, a fluorine-rich interlayer based on succinonitrile, fluoroethylene carbonate, and LiTFSI, denoted as succinonitrile interlayer (SNI), is developed to reduce the large interfacial impedance. The use of SNI rather than a conventional ester-based interlayer (EBI) effectively decreases the Li//CSE interfacial resistance and suppresses unfavorable interfacial side reactions. The LiF- and CF_x-rich solid electrolyte interphase (SEI), derived from SNI, on the Li metal electrode, mitigates the accumulation of dead Li and excessive SEI. Importantly, dehydrofluorination reactions of PVDF-HFP are significantly reduced by the introduction of SNI. A symmetric Li//CSE//Li cell with SNI exhibits a much longer cycle life than that of an EBI counterpart. A Li//CSE@SNI//LiFePO₄ cell shows specific capacities of 150 and 112 mAh g^-1 at 0.1 and 2 C (based on LiFePO₄), respectively. After 100 charge-discharge cycles, 98% of the initial capacity is retained.

Expert Opinion on P2Y12 Inhibitors Use in Management of Acute Coronary Syndromes: Focus on Ticagrelor

Ticagrelor is a potent, oral P2Y12 inhibitor used as a part of dual antiplatelet therapy (DAPT) in acute coronary syndromes (ACS). New evidence has emerged for its use in ACS, which may be crucial for the Indian context. This brought together nearly 150 experts in ACS management across the country who reviewed the current evidence and discussed the same through a series of 10 meetings on an online platform. With all experts' agreement, the key expert opinions for the P2Y12 inhibitors use in ACS management were finalized. These include the following. In ACS patients aged <75 years, with diabetes, a history of stroke/transient ischemic attack, and chronic kidney disease, ticagrelor may be preferred over other P2Y12 inhibitors. It may also be preferred in the elderly above 75 years with clopidogrel is a suitable alternative in patients at high-risk of bleeding. Rates of stent thrombosis are lower with ticagrelor than clopidogrel. In patients managed with fibrinolysis, use ticagrelor after 48 hours if streptokinase was the fibrinolytic agent or it can be used after 12 to 24 hours if fibrin-specific fibrinolytic was used. Rates of major bleeding in patients treated with fibrinolysis are similar to clopidogrel. Prehospital administration may be preferred over in-hospital administration with expected bleeding rates similar to clopidogrel. Switching among P2Y12 inhibitors should be done with due consideration of their pharmacodynamics. At present, DAPT should be continued for 12 months with discontinuation after three to six months in patients with high bleeding risk. The use of low dose ticagrelor may be considered in cases with high-bleeding risk. DAPT or ticagrelor continuation beyond one year should be individualized considering ischemic and bleeding risks. Dyspnea is a common, mild, and transient and does not necessitate ticagrelor discontinuation. Severe dyspnea should be investigated thoroughly. In conclusion, ticagrelor (180 mg, 90 mg, and 60 mg doses), a potent antiplatelet is expected to reshape the antiplatelet use in the management of ACS.

Role of climate change variables (standing water and rainfall) on dissipation of chlorantraniliprole from a simulated rice ecosystem

Chlorantraniliprole (CAP) is extensively used for rice pest management. Lack of information on the role of standing water and amount and timing of rainfall on CAP dissipation in rice ecosystem could hamper its prospective use. Present study was performed to investigate the effects of different water regimes (saturated, 5 and 10 cm standing water) and simulated rainfall (40 and 100 mm occurred at 4, 8 and 24 h after CAP application) on leaching, surface runoff and dissipation of CAP into components of rice ecosystem. The results showed highest concentration of CAP residues in soil and plant under saturated condition followed by 5 and 10 cm standing water conditions. Whereas, the highest concentration of CAP in leachates was detected under 10 cm standing water (12.19 ng mL^-1). The results revealed large amount of leaching (21.99 ng mL^-1) and surface runoff (42.25 ng mL^-1) losses of CAP when 100 mm rainfall occurred at 4 h after pesticide application. The total quantity of CAP residues in soil and plant was highest when rainfall occurred at 24 h after pesticide application under both the rainfall amounts. Water stagnation and high intensity rainfall occurred shortly after pesticide application will contribute to pesticide loss to non-target sites through surface run-off and leaching. There will be less pesticide available in soil for plant uptake which may not be sufficient to kill the target organisms.

Indigenous biobed to limit point source pollution of imidacloprid in tropical countries

Point pollution of pesticides originating from the washing of spraying machines could be controlled by biobed system and it is in use in temperate countries. The biobed system is yet to be established in tropical countries. An indigenous biobed system was prepared using local resources like rice straw, farm yard manures (FYM) and paddy field soil to suit the tropical climate. Lowermost 3 cm layer of the biobed system was filled with rice husk biochar to prevent leaching of pesticides from the system. This model system was tested with high doses of imidacloprid (178 mg/column), a commonly used pesticide against number of insect-pests in different crops, for its degradation. The bio-mix trapped a major part of the imidacloprid on the top most layer of the biobed column and only a very small part of imidacloprid recovered from the leachate. The biobed system could degrade 70.13% of applied imidacloprid within 15 days of the experiment and only 5.27% of the total pesticide recovered 90 days after incubation. Addition of biochar layer adsorbed imidacloprid from the outgoing leachate from the biobed column. Biomixture boosted microbial activity more particularly fungal population, which might be responsible for imidacloprid degradation. Microbial biomass carbon, and soil enzymes indicated faster dissipation of imidacloprid from the top layer of the biobed. This simple but efficient biobed system using local resources can fulfill the need of the small and marginal farmers of Asian countries for pesticide decontamination.

Composition Modulation of Ionic Liquid Hybrid Electrolyte for 5 V Lithium-Ion Batteries

Electrolyte is a key component in high-voltage lithium-ion batteries (LIBs). Bis(trifluoromethanesulfonyl)imide-based ionic liquid (IL)/organic carbonate hybrid electrolytes have been a research focus owing to their excellent balance of safety and ionic conductivity. Nevertheless, corrosion of Al current collectors at high potentials usually happens for this kind of electrolyte. In this study, this long-standing problem is solved via the modulation of the IL/carbonate ratio and LiPF₆ concentration in the hybrid electrolyte. The proposed electrolyte suppresses Al dissolution and electrolyte oxidation at 5 V (vs Li⁺/Li) and thus allows for ideal lithiation/delithiation performance of a high-voltage LiNi_0.5Mn_1.5O₄ (LNMO) cathode even at 55 °C. The underlying mechanism is examined in this work. Excellent cycling stability (97% capacity retention) for an LNMO cathode after 300 cycles is achieved. This electrolyte shows good wettability toward a polyethylene separator and low flammability. In addition, satisfactory compatibility with both graphite and Si-based anodes is confirmed. The proposed electrolyte design strategies have great potential for applications in high-voltage LIBs.

Dissipation of chlorantraniliprole in contrasting soils and its effect on soil microbes and enzymes

An experiment was set up to determine the rate of dissipation of chlorantraniliprole (CTP) from two soils with contrasting properties. The other objective of the study was to find out the effect of CTP on soil microorganisms (population, microbial biomass carbon and soil enzymes) under controlled environment. CTP residues when applied at recommended dose ((RD) (at 40 g a.i./ha)) could not be recovered either from alluvial soil or red soil at 60 days post application of CTP in a microcosm study. Higher clay content led to higher half-life in alluvial soil compared to red soil. CTP could not be recovered from RD treatment at 30 days after pesticide application under controlled environment. Faster dissipation of CTP was observed in rice rhizosphere soil with 23.89 and 34.65 days dissipation half-lives for RD and double the recommended dose (DRD) treatments, respectively. Different doses of chlorantraniliprole did not have considerable negative effect on actinomycetes, fungi, biological nitrogen fixers and phospahte solubilising bacteria except the bacteria population. Among the treatments, DRD recorded the lowest activity of dehyrodeganse, fluoresein diacetate hydrolase, acid and alkaline phosphatases followed by RD treatment. Microbial biomass carbon, β -glycosidase and urease did not vary significantly among the different doses of CTP. In general, RD did not have negative effcts on soil microbes. Hence, CTP can be recommeded in rice pest managment maintaining existing soil microbes and soil enzymes activity.

Candidate screening of blast resistance donors for rice breeding

Rice blast is one of the most serious diseases in the world. The use of resistant cultivars is the most preferred means to control this disease. Resistance often breaks down due to emergence of new races; hence identification of novel resistance donors is indispensable. In this study, a panel of 80 released varieties from National Rice Research Institute, Cuttack was genotyped with 36 molecular markers that were linked to 36 different blast resistance genes, to investigate the varietal genetic diversity and molecular marker-trait association with blast resistance. The polymorphism information content of 36 loci varied from 0.11 to 0.37 with an average of 0.34. The cluster analysis and population structure categorized the 80 National Rice Research Institute released varieties (NRVs) into three major genetic groups. The principal co-ordinate analysis displays the distribution of resistant and moderately resistant NRVs into different groups. Analysis of molecular variance result demonstrated maximum (97%) diversity within populations and minimum (3%) diversity between populations. Among tested markers, two markers (RM7364 and pi21_79-3) corresponding to the blast resistance genes (Pi56(t) and pi21) were significantly associated and explained a phenotypic variance of 4.9 to 5.1% with the blast resistance. These associated genes could be introgressed through marker-assisted to develop durable blast resistant rice varieties. The selected resistant NRVs could be good donors for the blast resistance in rice crop improvement research.

Carbonaceous Anodes Derived from Sugarcane Bagasse for Sodium-Ion Batteries

To realize the sustainability of Na-ion batteries (NIBs) for large-scale energy storage applications, a resource-abundant and cost-effective anode material is required. In this study, sugarcane bagasse (SB), one of the most abundant types of biowaste, is chosen as the carbon precursor to produce a hard carbon (HC) anode for NIBs. SB has a great balance of cellulose, hemicellulose, and lignin, which prevents full graphitization of the pyrolyzed carbon but ensures a sufficiently ordered carbon structure for Na⁺ transport. Compared with HC derived from waste apples, which are pectin-rich and have less cellulose than SB, SB-derived HC (SB-HC) has fewer defects and a lower oxygen content. SB-HC thus has a higher first-cycle sodiation/desodiation coulombic efficiency and better cycling stability. In addition, SB-HC has a unique flake-like morphology, which can shorten the Na⁺ diffusion length, and higher electronic conductivity (owing to more sp² -hybridized carbon), resulting in superior high-rate charge-discharge performance to apple-derived HC. The effects of pyrolysis temperature on the material characteristics and electrochemical properties, evaluated by using chronopotentiometry, cyclic voltammetry, and electrochemical impedance spectroscopy, are systematically investigated for both kinds of HC.

A Water-Soluble NaCMC/NaPAA Binder for Exceptional Improvement of Sodium-Ion Batteries with an SnO2 -Ordered Mesoporous Carbon Anode

SnO₂ @CMK-8 composite, a highly promising anode for Na-ion batteries (NIBs), was incorporated with polyvinylidene difluoride (PVDF), sodium carboxymethylcellulose (NaCMC), sodium polyacrylate (NaPAA), and NaCMC/NaPAA mixed binders to optimize the electrode sodiation/desodiation properties. Synergistic effects between NaCMC and NaPAA led to the formation of an effective protective film on the electrode. This coating layer not only increased the charge-discharge Coulombic efficiency, suppressing the accumulation of solid-electrolyte interphases, but also kept the SnO₂ nanoparticles in the CMK-8 matrix, preventing the agglomeration and removal of oxide upon cycling. The adhesion strength and stability towards the electrolyte of the binders were evaluated. In addition, the charge-transfer resistance and apparent Na⁺ diffusion of the SnO₂ @CMK-8 electrodes with various binders were examined and post-mortem analyses were conducted. With NaCMC/NaPAA binder, exceptional electrode capacities of 850 and 425 mAh g^-1 were obtained at charge-discharge rates of 20 and 2000 mA g^-1 , respectively. After 300 cycles, 90 % capacity retention was achieved. The thermal reactivity of the sodiated electrodes was studied by using differential scanning calorimetry. The binder effects on NIB safety, in terms of thermal runaway, are discussed.

Effect of Abiotic Factors on Degradation of Imidacloprid

The role of soil moisture, light and pH on imidacloprid dissipation was investigated. A high performance liquid chromatography (HPLC) based method was developed to quantify imidacloprid present in soil with a recovery of more than 82%. Rate of dissipation of imidacloprid from soil was faster in submerged condition compared to field capacity and air dried condition. Imidacloprid dissipated non-significantly between sterile and non-sterile soils, but at field capacity, the dissipation was faster in non-sterile soil compared to sterile soil after 60 days of incubation. Similarly, under submergence, the dissipation of imidacloprid was 66.2% and 79.8% of the initial in sterile and non-sterile soils, respectively. Imidacloprid was rather stable in acidic and neutral water but was prone to photo-degradation. Therefore, imidacloprid degradation will be faster under direct sunlight and at higher soil moisture.

Three-dimensional interpenetrating mesoporous carbon confining SnO2 particles for superior sodiation/desodiation properties

Nanosized SnO₂ particles (∼2 nm in diameter) are embedded in ordered mesoporous CMK-8 carbon with unique three-dimensional interconnected pore channels and used as a sodium-ion battery (NIB) anode. Due to the CMK-8 confinement effects, the growth of SnO₂ is suppressed during synthesis, leading to high material electroactivity. The CMK-8 not only serves as an electronic conducting pathway, but also creates interpenetrating tunnels, which guarantee electrolyte accessibility and thus Na⁺ transport throughout the electrode. Moreover, the change in the SnO₂ volume during sodiation/desodiation can be accommodated by the CMK-8 framework. With a high tap density of ∼1000 mg cm^-3 (vs. ∼800 mg cm^-3 for the conventional NIB anode, hard carbon), the SnO₂/CMK-8 anode shows a high reversible capacity of 800 mA h g^-1 and excellent rate capability, delivering 330 mA h g^-1 in ∼10 min. The electrode charge storage mechanism is examined using synchrotron X-ray diffraction. We confirm that CMK-8 incorporation can effectively promote the SnO₂-Sn conversion reaction and Sn-Na alloying reaction, which are known to be thermodynamically/kinetically difficult, increasing the electrode charge-discharge performance.

Microbial biomass and carbon mineralization in agricultural soils as affected by pesticide addition

A laboratory study was conducted with four pesticides, viz. a fungicide (carbendazim), two insecticides (chlorpyrifos and cartap hydrochloride) and an herbicide (pretilachlor) applied to a sandy clay loam soil at a field rate to determine their effect on microbial biomass carbon (MBC) and carbon mineralization (C(min)). The MBC content of soil increased with time up to 30 days in cartap hydrochloride as well as chlorpyrifos treated soil. Thereafter, it decreased and reached close to the initial level by 90th day. However, in carbendazim treated soil, the MBC showed a decreasing trend up to 45 days and subsequently increased up to 90 days. In pretilachlor treated soil, MBC increased through the first 15 days, and thereafter decreased to the initial level. Application of carbendazim, chlorpyrifos and cartap hydrochloride decreased C(min) for the first 30 days and then increased afterwards, while pretilachlor treated soil showed an increasing trend.

Bilateral carotid angioplasty and stenting

Bilateral carotid stenosis is generally treated by staged stenting procedure and rarely simultaneously due to concerns about hemodynamic impairment from stimulation of the carotid sinus baroreflex (severe bradycardia, hypotension) and the risk of cerebral hyperperfusion syndrome. Most of the accounts of bilateral carotid stenting are of small series. The aim of this study was to evaluate the feasibility and safety of simultaneous bilateral carotid angioplasty and stenting (CAS) in comparison with staged procedure. We retrospectively analyzed the procedural outcome and complications of bilateral CAS done between February 1995 and June 2004 in a consecutive series of 57 high-risk patients. Mean age was 64 +/- 9 years (male, 43; female 14). One hundred fifteen arteries were treated (one patient had bilateral internal carotid artery stenosis associated to an ostial common carotid artery stenosis). Thirty-nine patients were symptomatic (70%). Thirty-six patients had severe coronary artery disease. Seventeen patients underwent a simultaneous bilateral CAS (group 1), 40 in a staged manner (group 2). Among these 40 patients 10 were treated with a time interval of 24 hr, while the 30 other ones were treated with a time interval of 2 days to 2 months. A neuroprotection device was used in the last 42 patients. There was technical success in all patients and transient bradycardia and/or hypotension in 25 patients (44%). There was no prolonged bradycardia or hypotension. At 30 days, we observed in group 1 (simultaneous bilateral CAS) no transient ischemic attack (TIA), no minor stroke, one (5.8%) major stroke (hyperperfusion syndrome with brain hemorrhage leading to death in a patient under IIb/IIIa inhibitors), one myocardial infarction leading to death, and two (11.7%) death/stroke/myocardial infarction; in group 2 (staged procedure), two (5%) TIAs, no minor stroke, no major stroke, and one (2.5%) hyperperfusion syndrome with rapid recovery. Among the 10 patients treated with a time interval of 24 hr, we observed one TIA. Among carefully selected patients, bilateral CAS is feasible simultaneously or the day after, with a safety and complication rate comparable to that of large published series of CAS or endarterectomies in high-risk patients. Nevertheless, careful monitoring of the patient, blood pressure, and heart rate is mandatory to avoid complications related to hyperperfusion syndrome. Routine use of neuroprotection device and meticulous technique should improve the outcomes of bilateral CAS.

Percutaneous transluminal angioplasty using a new peripheral cutting balloon for stenosis of arch vessels in aorto arteritis

Percutaneous transluminal angioplasty (PTA) with or without stenting of steno-occlusions in the supra-aortic arch vessels in aortoarteritis is associated with higher residual stenosis and restenosis, particularly in those with diffuse disease. The use of the new peripheral cutting balloon (Boston Scientific Interventional Technologies, San Diego, CA, USA) in these lesions in aortoarteritis has not been described. We report here the first 2 cases of stand alone cutting angioplasty for 2 patients (3 arteries). One patient presented with a critical stenosis of the common carotid artery. We obtained a good immediate result but a restenosis appeared at 6 months, easily treated by a new angioplasty with cutting balloon and stent implantation. The second patient had an occlusion of the subclavian artery associated with a severe ostial vertebral artery stenosis. The immediate result was excellent and the 6-month clinical and angiographic control showed no restenosis.

Percutaneous transluminal angioplasty using a cutting balloon for stenosis of the arch vessels in aortoarteritis

Percutaneous transluminal angioplasty with or without stenting of steno-occlusions in the supra-aortic arch vessels in aortoarteritis is associated with suboptimal results and higher restenosis rates, particularly in those with diffuse disease. We report two cases of stand-alone cutting balloon angioplasty for patients who presented with critical stenosis of the common carotid artery, and occlusion of the subclavian artery, respectively.

Carotid artery stenting with filter protection

BACKGROUND

Neurologic events associated with distal embolization of debris during percutaneous carotid artery stenting complicate the procedure. Filter devices for cerebral protection potentially reduce the risk of embolization and other neurologic events. We studied the feasibility, safety, and efficacy of carotid artery stenting with a filter device.

METHODS AND RESULTS

Between January 2002 and January 2003, a total of 22 consecutive patients (30 lesions) who had >70% diameter stenosis of the internal carotid artery underwent carotid artery stenting with filter protection at our institute. The mean age of the patients was 64+/-9 years; 14 were men and 8 women, and 15 had neurologic symptoms. A stent was successfully implanted in 29 lesions. It was possible to position a filter device in all the 29 lesions. Neurologic complications during the procedure, in the hospital, and at 30-day clinical follow-up occurred in 2 patients. One patient suffered a minor stroke that resolved within 24 hours. None of the patients had a major embolic stroke. There was one death from intracerebral hemorrhage related to hyperperfusion and the use of a glycoprotein IIb/IIIa inhibitor.

CONCLUSIONS

Filter protection during carotid artery stenting seems technically feasible, safe, and effective. In the present study, the incidence of embolic neurologic events was low.

Renal artery involvement in patients of coronary artery disease undergoing coronary angiography--a prospective study

METHODS

We prospectively studied the angiographic incidence of renal artery stenosis in 1000 consecutive patients who underwent coronary angiography for clinically suspected coronary artery disease since December, 1998. Selective renal arteriography was performed in all the patients (mean age 57 years, 74.6% males) after coronary angiography.

RESULTS

Systemic arterial hypertension was present in 52%, 29.1% were smokers, 21% had diabetes and 31.2% had hypercholesterolemia. Significant coronary artery diseases was found in 849 (84.9%) patients. Of the total patient cohort, 103 (10.3%) patients had renal artery disease; 78 (7.8%) had insignificant stenosis (> 50%) and significant renal artery stenosis (< 50%) was identified in 25 (2.5%) patients. Three had bilateral renal artery stenosis. Comparisons were made between renal artery stenosis and risk factor profile. There was no statistically significant association between renal artery stenosis and parameters like diabetes mellitus, hypertension, smoking, lipid levels and serum creatinine.

CONCLUSION

In our study, the absolute number of cases with significant renal artery stenosis is small, so no statistical analysis could be performed to demonstrate the relationship of presence of renal artery stenosis with severity of CAD. However patients with severe coronary artery disease or having multiple risk factor showed a trend towards increased prevalence of renal artery stenosis, hence renal angiography should be done for this subset of patients.

Carotid artery involvement in patients of atherosclerotic coronary artery disease undergoing coronary artery bypass grafting

BACKGROUND

Patients with concomitant critical carotid and coronary artery disease are at risk of major neurological events while undergoing coronary artery bypass grafting. The presence of carotid artery stenosis increases the stroke rate in the perioperative period. In an effort to reduce the stroke rate, many institutions perform routine preoperative noninvasive assessment of the carotid arteries.

METHODS AND RESULTS

We analyzed the clinical and laboratory data of 1,200 patients who underwent coronary artery bypass surgery in the last 2 years. Carotid Doppler was normal in 186 patients (15.5%), and showed <30% stenosis in 796 (66.3%), 30%-50% in 110 (9.2%), 50%-70% stenosis in 64 (5.3%) and critical (>70%) stenosis in 44 (3.7%) patients. Conventional risk factors such as hypercholesterolemia, hypertension, smoking and family history were not independent predictors of carotid artery stenosis. However, diabetes as a risk factor had a significant association with carotid artery disease (79.6% v. 43.8%, p<0.02). There was a trend towards increased prevalence of carotid artery stenosis in patients with > or = 2 risk factors (84.3% v. 68.8%). Patients with significant carotid artery stenosis had severe coronary artery disease (triple-vessel disease 93.3%, left main coronary artery disease 12.0%). Out of 44 patients with critical carotid artery stenosis, 27 were subjected to carotid angiography. Doppler findings correlated well with angiography. Seventeen patients underwent carotid artery intervention. None had any perioperative neurological events. A total of 5 (0.4%) patients had a major stroke. Coronary artery bypass grafting was done in 27 patients with critical stenosis without any intervention. The stroke rate (11.1%) was higher in these patients compared to patients with < 70% carotid artery disease or post-carotid intervention (2.5%) patients. Thus, untreated >70% carotid artery stenosis was associated with a higher stroke rate.

CONCLUSIONS

Doppler screening of the carotid artery is helpful in detecting the subgroup of patients at increased risk of stroke. Patients with critical carotid artery stenosis should be subjected to angiography. Prophylactic intervention may reduce the occurrence of stroke in the perioperative period.

Antiproliferative effects of IFN-alpha correlate with the downregulation of nuclear factor-kappa B in human Burkitt lymphoma Daudi cells

Interferon-alpha (IFN-alpha) is known to exhibit antiviral, antiproliferative, and immunomodulatory properties through mechanisms still not fully understood. Nuclear transcription factor-kappaB (NF-kappaB) plays a major role in viral replication, cell proliferation, and immune response. Whether antiproliferative effects of IFN are mediated through suppression of NF-kappaB is not known. We, therefore, examined the relationship between the antiproliferative effects of IFN-alpha and NF-kappaB activity in a human Burkitt lymphoma Daudi cell line. These cells were found to constitutively express high levels of active NF-kappaB that cannot be further activated by tumor necrosis factor (TNF). Treatment of cells with IFN-alpha suppressed the activated NF-kappaB in a dose-dependent manner, with an optimum effect at 10 U/ml in 72 h. Suppression of NF-kappaB correlated with a concomitant decrease in the cytoplasmic levels of IkappaBalpha, the inhibitory protein of NF-kappaB, known to be regulated by NF-kappaB. Downregulation of constitutive NF-kappaB activity correlated with a decrease in cell proliferation by IFN-alpha. Overall, our results suggest that IFN-alpha is a potent suppressor of constitutive NF-kappaB, which may contribute to the inhibition of cell proliferation.

Radiation induced oxidative stress: I. Studies in Ehrlich solid tumor in mice

Understanding the response of tumors to ionizing radiation might potentially lead to improvement in tumor control and patient morbidity. Since the antioxidant status is likely to be linked to radioresponse, its modulation needs to be examined. Therefore, Swiss albino male mice (7-8 weeks old) with Ehrlich solid tumors were irradiated with different doses of gamma rays (0-9 Gy) at a dose rate of 0.0153 Gy/s; and enzymes involved in antioxidant functions were determined in the tumors. Radiation effects in terms of oxidative damage, LDH, nitric oxide and DNA fragmentation were also examined. In tumors, the specific activity of SOD was increased with dose but declined 6 Gy onwards. GST, DTD and GSH showed an almost progressive increase. These enhanced activities might have resulted from the increased protein expression. This possibility was supported by the Western Blot analysis for GST protein. These changes might be closely linked to the radiation-induced oxidative stress as reflected by the enhanced levels of peroxidative damage, DNA fragmentation, LDH activity and nitric oxide levels. These findings may have relevance to radiation therapy of cancer as the elevated antioxidant status of irradiated tumors is likely to limit the effectiveness of radiation dose and adversely affect the therapeutic gain.

Percutaneous transluminal myocardial revascularisation: current status and future perspectives

Percutaneous transluminal myocardial revascularisation presently appears to be a potential palliative treatment for coronary artery disease, neither controlled with drugs nor amenable to available coronary revascularisation techniques. Ongoing trials will provide answer to short and long term efficacy. Recent developments using angiogenic growth factors appear very promising, and the role of growth factors as an adjunct to percutaneous transmyocardial revascularisation with laser remains to be seen.

Coronary stenting without pre-dilatation: an observational study

Conventional coronary stenting is done after pre-dilatation of the lesion. The bleeding complications and incidence of subacute stent thrombosis have been reduced significantly by the use of antiplatelet agents and high pressure balloon inflation to ensure complete stent expansion. Elective stenting also can be done without pre-dilatation by "stent alone technique." This approach significantly reduces the procedural cost and ischaemia time, avoiding potential complications such as abrupt vessel closure because of extensive dissection after conventional angioplasty and prior to stent deployment. Eighty patients of stable angina pectoris suitable for coronary angioplasty underwent stenting without pre-dilatation. Out of the 100 stents used, 38 were hand-crimped and 62 were pre-mounted. The target vessels were left anterior descending artery in 56 percent, right coronary artery in 32 percent and left circumflex in 12 percent. The procedure was successful in 88 percent lesions. In 12 percent stenting could be done only after pre-dilatation. In all these, there was proximal tortuosity and calcification. The fluoroscopy time was 10.2 +/- 4.5 minutes. The average number of balloons used per lesion was 1.08. Stent embolisation occurred in only one patient. There were no major adverse cardiac events in any of the patients. Thus stenting without pre-dilatation is safe. Patients who are eligible for stenting without pre-dilatation are those with stable angina pectoris without fluoroscopically visible calcium or coronary artery tortuosity and with lesions of moderate complexity.

TNF-induced signaling in apoptosis

Out of the almost 17 members of the TNF superfamily, TNF is probably the most potent inducer of apoptosis. TNF activates both cell-survival and cell-death mechanisms simultaneously. Activation of NF-kB-dependent genes regulates the survival and proliferative effects pf TNF, whereas activation of caspases regulates the apoptotic effects. TNF-induced apoptosis is mediated primarily through the activation of type I receptors, the death domain of which recruits more than a dozen different signaling proteins, which together are considered part of an apoptotic cascade. This cascade does not, however, account for the role of reactive oxygen intermediates, ceramide, phospholipases, and serine proteases which are also implicated in TNF-induced apoptosis. This cascade also does not explain how type II TNF receptors which lack the death domain, induce apoptosis. Nevertheless, this review of apoptosis signaling will be limited to those proteins that makeup the cascade.

Coil embolization of a giant atherosclerotic coronary artery aneurysm

The incidence of the coronary artery aneurysm varies from 1.5-5%. Atherosclerosis is the most common cause of coronary artery aneurysm in adults. A discrete, giant, saccular atherosclerotic coronary artery aneurysm in an artery without significant proximal stenosis is rare. We report the first such case of a giant atherosclerotic coronary artery aneurysm successfully treated with coil embolization.

Percutaneous mechanical mitral commissurotomy with a newly designed metallic valvulotome: immediate results of the initial experience in 153 patients

BACKGROUND

Percutaneous balloon valvotomy has become a common treatment of mitral stenosis, but the cost of the procedure remains a limitation in countries with restricted financial resources, leading to a frequent reuse of the disposable catheters. To overcome this limitation, a reusable metallic valvotomy device has been developed with the goals of both improving the mitral valvotomy results and decreasing the cost of the procedure.

METHODS AND RESULTS

The device consists of a detachable metallic cylinder with 2 articulated bars screwed onto the distal end of a disposable catheter whose proximal end is connected to an activating pliers. By the transseptal route, the device is advanced across the valve over a traction guidewire. Squeezing the pliers opens the bars up to a maximum extent of 40 mm. The clinical experience consisted of 153 patients with a broad spectrum of mitral valve deformities. The procedure was successful in 92% of cases and resulted in a significant increase in mitral valve area, from 0.95+/-0.2 to 2. 16+/-0.4 cm2. No increase in mitral regurgitation was noted in 80% of cases. Bilateral splitting of the commissures was observed in 87%. Complications were 2 cases of severe mitral regurgitation (1 requiring surgery), 1 pericardial tamponade, and 1 transient cerebrovascular embolic event. In this series, the maximum number of consecutive patients treated with the same device was 35.

CONCLUSIONS

The results obtained with this new device are encouraging and at least comparable to those of current balloon techniques. Multiple uses after sterilization should markedly decrease the procedural cost, a major advantage in countries with limited resources and high incidence of mitral stenosis.

Elective coronary artery stenting--immediate and follow up results

Elective coronary artery stenting was performed in 242 consecutive patients in our centre for complex lesions (Type B, C), proximal lesions, restenotic lesions, total occlusion and venous grafts. The procedural success rate was 94.21%. Three patients (1.23%) required emergency coronary artery bypass surgery. Acute and sub-acute thrombosis rate was 1.26% and 4.13%, respectively. There was one in-hospital death (0.41%). 164 patients were followed up clinically for a mean period of 11 +/- 6 months (range 1 month to 30 months). Angiographic follow up was done in 68 patients with a restenosis rate of 16.17%.

Balloon mitral valvuloplasty with bifoil catheter: immediate and long-term follow-up results

This report documents clinical and hemodynamic benefits of balloon mitral valvuloplasty (BMV) using a bifoil balloon catheter from a single center in 415 consecutive cases of rheumatic mitral stenosis (MS). The procedure was successful in 396 (95.2%) patients, with an increase in mitral valve area (MVA) from 0.82+/-0.35 cm2 to 2.21+/-0.24 cm2 (P < 0.001). There were 2 (0.48%) in-hospital deaths, and 6 (1.44%) patients developed acute mitral regurgitation. The procedural and fluroscopy time was reduced significantly from 52+/-11 and 38+/-6 min to 33+/-7 and 19+/-5 min, respectively, after modifications of technique in our last 326 cases. The bifoil balloon catheter technique is safe and effective, and provides excellent hemodynamic benefits which are sustained at long-term follow-up. This technique should be considered as an addition to the existing armamentarium of interventional cardiologists performing mitral balloon valvuloplasty.

Severity of mitral regurgitation in mitral valve prolapse syndrome. A Doppler echocardiographic study

Thirty-three consecutive patients with mitral valve prolapse with a systolic murmur were evaluated using pulsed doppler echocardiography to quantify the severity of mitral regurgitation. There were thirteen (39%) patients with mild regurgitation, twelve patients (36%) with moderate regurgitation and eight patients (24%) with severe regurgitation. It was noticed that, all the patients with severe regurgitation had posterior leaflet prolapse. In contrast, patients with anterior leaflet prolapse had either mild or moderate regurgitation only. Our results suggest that the degree of mitral regurgitation differs depending on the leaflet that shows the prolapse, which may be of importance in the followup of patients with mitral valve prolapse.

Electrocardiographic left atrial enlargement--correlation with echo

To assess the utility of electrocardiogram in identifying left atrial enlargement, electrocardiogram of 600 consecutive patients were correlated with their M-mode echocardiographic findings. Left atrial enlargement, as reflected by P terminal force in V1 had sensitivity of 79%, specificity 91%, predictive value 85% and accuracy of 86%. Patients older than 30 years with large left atrium (greater than 5.0 cm) had atrial fibrillation more frequently than younger patients (P less than 0.001). It is concluded that P terminal force in V1 is a reliable indicator of left atrial enlargement.

Low dose metoprolol in acute myocardial infarction

A study of the effects of low dose Metoprolol was undertaken in 37 patients with acute myocardial infarction. These patients were randomly divided into three groups depending on the dose of the drug per kg body weight. Group I, consisting of 18 patients, received 0.36 to 0.65 mg per kg per day, Group II (10 patients) received 0.66 to 0.99 mg/kg/day, and Group III (9 patients) 1 to 1.81 mg/kg/day. To assess the degree of beta blockade achieved, the parameters that were evaluated were the fall in blood pressure and heart rate. There was a fall in systolic blood pressure which ranged from 7 to 17%, and fall in heart rate of 6.6 to 12.8% in the 3 groups over the 48-hour study period. These observations were compared with the results obtained from the Goteberg Metoprolol trial and Metoprolol in acute myocardial infarction (MIAMI) trials wherein 200 mg of Metoprolol per day were used. Our preliminary observations suggest that Indian patients may not need such a high dose, and Metoprolol at 50-100 mg per day would probably be sufficient to get the desired effect.

Relapsing polychondritis--a case report and review of literature

A case of relapsing polychondritis with aortic aneurysm is presented and relevant literature reviewed. Only one case of relapsing polychondritis has been previously reported in Indian literature. Increased awareness of this relatively rare, multi-system disease is warranted, to facilitate the diagnosis.

Methylation of repetitive DNA sequences in the brain during aging of the rat

Methylation of repetitive DNA sequences (RDS) of the genomic DNA of the brain of 15- and 88-week old rats was analysed by digestion with HpaII, MspI, EcoRI + HpaII and EcoRI + MspI followed by end-labelling. mCpG doublets are present in two RDS of approximately 5 and 0.4 kb, and are also randomly distributed throughout the genome. Hemimethylated mCpC doublets also occur. Both mCpG and mCpC doublets are found more in the old than in the young. This age-related increase in DNA methylation occurs both at CCGG sites of the RDS and in the entire genome. Such increase in DNA methylation may alter chromatin conformation and gene expression in the brain as the rat ages.

Cyanosis in uncomplicated atrial septal defect

An unusual case of secundum type atrial septal defect with central cyanosis, without any associated conditions to account for cyanosis is presented. The possible mechanism of cyanosis is discussed.