Predictive efficacy of Framingham's risk score in Indian scenario--a retrospective case-control study

To assess the predictive ability of Framingham's risk score in primary prevention in our population, 252 cases and 212 age and sex matched controls were taken up for study. Those patients, who were presenting for the first time with acute coronarysyndrome (ACS) and who did not have any prior manifestations of coronary artery disease (CAD) and whose medical records were available formed the patient group. Framingham's risk score was calculated and the corresponding 10 years risk was assessed in each of them. The patients and controls were divided into two groups--diabetic and non-diabetic. Depending on the 10 years risk, they were further grouped into high risk (10 years risk > 20%), moderately high risk (10 years risk 10 to 20%) and low risk (10 years risk less than 10%). Results were compared and statistically analysed. In the diabetic patients with ACS 14% would have qualified as high risk, 33% as moderately high risk and 53% as low risk whereas in diabetic patients without any manifestation of CAD the distribution was 4% in the high risk, 54% in the moderately high risk and 42% in the low risk. In the non-diabetic subjects, amongst the patients of ACS, 20% would have been in high risk, 39% in moderately high risk and 41% in the low risk. The corresponding figures in the non-diabetic control subjects were 10% in high risk, 22% in the moderately high risk and 68% in the low risk. In the non-diabetic subjects, the mean risk was significantly more in patients than in controls (14.15% versus 8.61%, p <0.01). However, in the diabetic patients there was no significant difference in the mean projected risk between patients with ACS and patients without any manifestation of CAD (11.37% versus 10.41%, p>0.05).

Colossal magnetodielectric effects in DyMn2O5

We have investigated the detailed magnetic field dependence of the electric polarization and dielectric constant in (Tb,Dy,Ho)Mn2O5 where magnetic and ferroelectric transitions are intimately coupled. Our fundamental discovery is the unprecedented large change of the dielectric constant with magnetic field, particularly in DyMn2O5, associated with an unusual commensurate-incommensurate magnetic transition. This extraordinary effect appears to originate from the high sensitivity of the incommensurate state to external perturbation.

Localization and interaction effects in strongly underdoped La2-xSrxCuO4

The in-plane magnetoresistance (MR) in La(2-x)SrxCuO4 films with 0.03< x <0.05 has been studied in the temperature range 1.6 to 100 K, and in magnetic fields up to 14 T, parallel and perpendicular to the CuO2 planes. The behavior of the MR is consistent with a predominant influence of interaction effects at high temperatures, switching gradually to a regime dominated by spin scattering at low T. Weak localization effects are absent. A positive orbital MR appears close to the boundary between the antiferromagnetic and the spin-glass phase, suggesting the onset of Maki-Thompson superconducting fluctuations deep inside the insulating phase.

Electric polarization reversal and memory in a multiferroic material induced by magnetic fields

Ferroelectric and magnetic materials are a time-honoured subject of study and have led to some of the most important technological advances to date. Magnetism and ferroelectricity are involved with local spins and off-centre structural distortions, respectively. These two seemingly unrelated phenomena can coexist in certain unusual materials, termed multiferroics. Despite the possible coexistence of ferroelectricity and magnetism, a pronounced interplay between these properties has rarely been observed. This has prevented the realization of multiferroic devices offering such functionality. Here, we report a striking interplay between ferroelectricity and magnetism in the multiferroic TbMn2O5, demonstrated by a highly reproducible electric polarization reversal and permanent polarization imprint that are both actuated by an applied magnetic field. Our results point to new device applications such as magnetically recorded ferroelectric memory.

Percolative conduction in the half-metallic-ferromagnetic and ferroelectric mixture of (La, Lu, Sr)MnO3

The immiscibility between rhombohedral La(5/8)Sr(3/8)MnO3 and hexagonal LuMnO3 leads to a microm-scale heterogeneous mixture of half-metallic-ferromagnetic and insulating-ferroelectric phases. Electronic conduction of the mixture exhibits nearly ideal percolation behavior in the paramagnetic state with a threshold of 0.224(5) metal volume fraction and a resistivity scaling exponent t=2.1+/-0.1, consistent with the predicted universal behavior of classical percolation. However, far below T(C), t increases to 2.4+/-0.1, probably resulting from intergrain tunneling. Therefore, this system represents a unique example of the temperature-induced crossover from universal to nonuniversal behavior of t.

Classical capacity of the lossy bosonic channel: the exact solution

The classical capacity of the lossy bosonic channel is calculated exactly. It is shown that its Holevo information is not superadditive, and that a coherent-state encoding achieves capacity. The capacity of far-field, free-space optical communications is given as an example.

Enhanced granulation in UASB reactor treating low-strength wastewater by natural polymers

Reetha (Sapindus trifoliata) seed extract and Chitosan were used as additives in the sludge bed of a UASB reactor treating low strength wastewater to enhance granulation. Five parallel laboratory scale UASB reactors were operated for 250 days with synthetic wastewater feed containing COD in the range of 600-800 mg/L. The reactors were seeded with spent sludge from a full-scale 5MLD UASB treatment plant at Jajmau, Kanpur, India. The seed sludge contained little or no granules. Different additives in the five reactors were as follows: control with no additive, cationic part of Reetha extract as additive, anionic part of Reetha extract as additive, bulk Reetha extract as additive and Chitosan as additive. The granulation rapidly increased in all the reactors beyond the 90th day of operation. The mean granule sizes as well as the fraction of granular sludge (particle size > or = 100 microm) were more in the presence of some of the additives compared to the control reactor. Chitosan significantly enhanced granulation followed by the cationic and anionic fractions of the Reetha extract. The bulk Reetha extract did not show enhancement of granulation. The ESEM/EDAX results showed that the bigger granules (3-4 mm) had porous structure and appeared as conglomerates of smaller granules.

Colony-Stimulating Activity of Fetal Liver Cells: Synergistic Role of Stem Cell Factor in Bone Marrow Recovery from Aplastic Anemia

Previously, we and others have shown that fetal liver infusion (FLI) leads to autologous hematopoietic improvement in 40-54% of patients with aplastic anemia. However, whether this recovery was spontaneous or the effect of the infused liver cells was not clear. To dissect the role of FLI in autologous hematopoietic recovery, the colony-supporting potential of fetal liver-conditioned medium (FLCM) was evaluated in bone marrow (BM) cells of normal adult and aplastic anemia patients. In both cases, each sample of FLCM supported the growth of colony-forming cells in semi solid culture medium. The FLCM was assayed for the presence of four principal colony-stimulating cytokines, namely stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and erythropoietin (Epo). While GM-CSF, IL-3, and Epo were present in insignificant amounts or were altogether absent, 50-635 pg/ml of SCF was found in 8 of the 13 FLCM samples tested. Preliminary results of bioneutralization assay indicated the possible role of SCF, secreted by the FL cells, in colony-supporting activity of aplastic anemia and normal BM cells. Overall, our in vitro study implicates the paracrine role of infused FL cells in regenerating autologous hematopoiesis in aplastic anemia patients.

Contra-directional two-beam coupling by use of a single input beam in an iron-doped lithium niobate multimode fiber

Experimental results are presented for 1,800 contra-directional two-beam coupling (TBC) measurements in a single crystal fiber of LiNbO8:Fe using a single incident beam and its Fresnel reflection off the back surface of the fiber. To our knowledge, this is the first time that volume gratings have been written in a fiber using this beam coupling geometry. At small f-numbers, the TBC efficiency has been predicted to decrease in bulk LiNbO3:Fe due to the erasure of the weak gratings by the dark conductivity. We present experimental results validating the published theory and show experimentally that confinement of the interfering beams in a fiber geometry overcomes this limitation.

Percolative Superconductivity in Mg1-xB2

Our results from various transport experiments on Mg1-xB2 indicate a surprising effect associated with the presence of a Mg deficiency in MgB2: the phase separation between Mg-vacancy rich and Mg-vacancy poor phases. The Mg-vacancy poor phase is superconducting, but the insulating nature of the Mg-vacancy rich phase probably originates from the Anderson (disorder-induced) localization of itinerant carriers. Furthermore, electron diffraction measurements indicate that within vacancy-rich regions these defects tend to order with intriguing patterns. This electronic phase separation in Mg1-xB2 shows similar, but also distinct characteristics compared with that observed in La(2)CuO(4+delta).

Validity of the paraxial approximation in the focal region of a small-f-number lens

For small- f -number lenses, whereas the paraxial approximation cannot be used for a description of propagation of light from the lens to the focal region, it is shown that the approximation is still valid for propagation of light over relatively small distances in the region near the focus.

Study on early intervention with ACE inhibitor in myocardical infarction and short term outcome

The present study was carried out on 100 patients with acute myocardial infarction (AMI) being treated with angiotensin converting enzyme (ACE) inhibitor and another 80 patients with conventional treatment but without ACE inhibitor during the period from May 1, 1995 to August 7, 1996 in Medical College, Calcutta. Clinical and other laboratory investigations including echocardiographic parameters were noted and recorded meticulously within 24-48 hours after AMI and repeated at 4th week. The present study based on non-invasive methods other than haemodynamic methods has shown that the echocardiographic assessment of left ventricular functional parameters after 4 weeks of ACE inhibitor therapy (n = 100) were better in treated group in comparison to control group without ACE inhibitor (n = 80) and the difference was statistically significant at 99% level of confidence. Overall mortality was 4% in ACE inhibitor group and 8.75% in the control group. This short term study with early intervention with ACE inhibitor within 48 hours of AMI has shown statistically significant evidence of beneficial effect of ACE inhibitor in improving the ventricular functional parameters and also reducing short term mortality from cardiac cause within 4 weeks compared to the group not receiving ACE inhibitors.

Multiple antibiotic changes during the first 72 hours of hospitalization

BACKGROUND

Increasing concern about inappropriate antibiotic use prompted us to examine whether our patients were receiving frequent and perhaps unwarranted changes of antibiotic therapy.

METHODS

We evaluated antibiotic prescribing by the physicians in the Emergency Department and by those on the inpatient medical service during the first 72 hours of hospitalization in 119 patients admitted with suspected serious infections to an acute care, university-affiliated, municipal teaching hospital. The appropriateness of antibiotic prescriptions was assessed independently and retrospectively by 2 infectious disease specialists (each based at a different hospital) using a 4-grade scale (from 1 = wrong choice to 4 = appropriate). Of their evaluations of the 427 antibiotic regimens given to the 119 patients during 4 defined intervals during their first 72 hours of hospitalization, 90% agreed with each other within 1 grade. Their evaluations were then compared with the selections that had been made at each interval by the prescribing physicians.

RESULTS

Successive prescribing physicians changed the antibiotic regimens in 77% of cases during the first 24 hours and in 56% during the next 48, often without apparent clinical or microbiologic indications. By 72 hours, the 119 patients had received a mean of 3.1 +/- 1.3 (+/-SD) different antibiotics, and 40 received between 4 and 7. Only 7% of the patients had no change in the regimen prescribed originally.

CONCLUSIONS

Many patients had multiple changes of antibiotics, often unnecessarily, resulting in exposure to too many agents.

G protein-coupled receptor signaling in human ductal pancreatic cancer cells: neurotensin responsiveness and mitogenic stimulation

Neuropeptides and their corresponding G protein-coupled receptors (GPCRs) are increasingly implicated in the autocrine/paracrine stimulation of growth of human cancers. We report that neurotensin induced rapid Ca2+ mobilization from intracellular stores followed by Ca2+ influx in five human ductal pancreatic cancer cell lines: HPAF-II, Capan-1, Capan-2, PANC-1, and MIA PaCa-2. In addition, most cell lines exhibited Ca2+ responses to multiple neuropeptides including bombesin, bradykinin, cholecystokinin, and vasopressin and to bioactive lipids, including lysophosphatidic acid (LPA), that also act via GPCRs. The well-differentiated line HPAF-II responded to at least seven independent GPCR agonists. The concentrations of neurotensin required to induce half-maximal effects (EC50) in HPAF-II and PANC-1 cells were 5 and 8nM, respectively. Digital fluorescence image analysis to measure Ca2+ responses in single cells revealed that 90% or more of HPAF-II and PANC-1 cells responded to 10nM neurotensin. Addition of neurotensin to PANC-1 cells also induced rapid and dose-dependent extracellular-regulated protein kinase (ERK-1 and ERK-2) activation and subsequently, stimulated DNA synthesis. The signaling complexity of GPCRs uncovered by these studies reveals a new aspect in the biology of human pancreatic cancer and could offer the basis for new approaches to the treatment of this disease.

G protein-coupled receptor signaling in human ductal pancreatic cancer cells: neurotensin responsiveness and mitogenic stimulation

Neuropeptides and their corresponding G protein-coupled receptors (GPCRs) are increasingly implicated in the autocrine/paracrine stimulation of growth of human cancers. We report that neurotensin induced rapid Ca2+ mobilization from intracellular stores followed by Ca2+ influx in five human ductal pancreatic cancer cell lines: HPAF-II, Capan-1, Capan-2, PANC-1, and MIA PaCa-2. In addition, most cell lines exhibited Ca2+ responses to multiple neuropeptides including bombesin, bradykinin, cholecystokinin, and vasopressin and to bioactive lipids, including lysophosphatidic acid (LPA), that also act via GPCRs. The well-differentiated line HPAF-II responded to at least seven independent GPCR agonists. The concentrations of neurotensin required to induce half-maximal effects (EC50) in HPAF-II and PANC-1 cells were 5 and 8nM, respectively. Digital fluorescence image analysis to measure Ca2+ responses in single cells revealed that 90% or more of HPAF-II and PANC-1 cells responded to 10nM neurotensin. Addition of neurotensin to PANC-1 cells also induced rapid and dose-dependent extracellular-regulated protein kinase (ERK-1 and ERK-2) activation and subsequently, stimulated DNA synthesis. The signaling complexity of GPCRs uncovered by these studies reveals a new aspect in the biology of human pancreatic cancer and could offer the basis for new approaches to the treatment of this disease.

Focusing by small-f-number lenses in the presence of aberrations

A method of finding the three-dimensional distribution of light in the focal region of small- f -number lenses that have arbitrary surface curvatures is described. The Fresnel approximation is not used, and the effects of aberration are included. A comparison of the numerical results with experimental measurements for a commercially obtained plano-convex lens is provided.

Geometry-dependent electronic properties of highly fluorescent conjugated molecules

We present a combined experimental/theoretical study of the electronic properties of conjugated para-phenylene type molecules under high pressure up to 80 kbar. Pressure is used as a tool to vary the molecular geometry and intermolecular interaction. The influence of the latter two on singlet and triplet excitons as well as polarons is monitored via optical spectroscopy. We have performed band structure calculations for the planar poly(para-phenylene) and calculated the dielectric function. By varying the intermolecular distances and the length of the polymer repeat unit the observed pressure effects can be explained.

Metallic nonsuperconducting phase and D-wave superconductivity in Zn-substituted La1.85Sr0.15CuO4

Measurements of the resistivity, magnetoresistance, and penetration depth were made on films of La1.85Sr0.15CuO4, with up to 12 at. % of Zn substituted for the Cu. The results show that the quadratic temperature dependence of the inverse square of the penetration depth, indicative of d-wave superconductivity, is not affected by doping. The suppression of superconductivity leads to a metallic nonsuperconducting phase, as expected for a pairing mechanism related to spin fluctuations. The metal-insulator transition occurs in the vicinity of k(F)l approximately 1, and appears to be disorder driven, with the carrier concentration unaffected by doping.

Multisubstrate biodegradation kinetics of naphthalene, phenanthrene, and pyrene mixtures

Biodegradation kinetics of naphthalene, phenanthrene and pyrene were studied in sole-substrate systems, and in binary and ternary mixtures to examine substrate interactions. The experiments were conducted in aerobic batch aqueous systems inoculated with a mixed culture that had been isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Monod kinetic parameters and yield coefficients for the individual compounds were estimated from substrate depletion and CO(2) evolution rate data in sole-substrate experiments. In all three binary mixture experiments, biodegradation kinetics were comparable to the sole-substrate kinetics. In the ternary mixture, biodegradation of naphthalene was inhibited and the biodegradation rates of phenanthrene and pyrene were enhanced. A multisubstrate form of the Monod kinetic model was found to adequately predict substrate interactions in the binary and ternary mixtures using only the parameters derived from sole-substrate experiments. Numerical simulations of biomass growth kinetics explain the observed range of behaviors in PAH mixtures. In general, the biodegradation rates of the more degradable and abundant compounds are reduced due to competitive inhibition, but enhanced biodegradation of the more recalcitrant PAHs occurs due to simultaneous biomass growth on multiple substrates. In PAH-contaminated environments, substrate interactions may be very large due to additive effects from the large number of compounds present.

Bradycardia, reversible panconduction defect and syncope following self-medication with a homeopathic medicine

Alkaloid extracts from the plant Aconitum species have been used in various forms of herbal remedies predominantly as anti-inflammatory and analgesic agents. Many of these alkaloids are extremely potent cardiotoxins and documented cases of various arrhythmias with fatal outcomes have been reported. We report a case of self-medication with 'tincture of aconite' resulting in severe bradycardia, reversible panconduction defect evidenced by sinus inactivity, atrioventricular dissociation with idiojunctional rhythm and left bundle branch block pattern resulting in hypotension and syncope. Complete reversal of ECG findings with marked improvement in symptoms was noted within a few hours. Herbal medicines containing aconite alkaloids may result in severe cardiotoxicity, and strict regulatory measures are warranted to curb unsupervised use for therapeutic purposes.