Effect of plasma lysozyme on live Mycobacterium tuberculosis

The role of plasma lysozyme of normal healthy subjects (NHS, n = 12) and active pulmonary tuberculosis (ATB) patients (n = 15) on the innate immune mechanism was studied by the binding activity of lysozyme on live Mycobacterium tuberculosis. Plasma samples of NHS and ATB patients treated with live M. tuberculosis for 4 h and 24 h time points showed a significant decrease in the plasma lysozyme level when compared to the untreated samples (4 h, P < 0.001; 24 h, P < 0.001). Pretreatment of live M. tuberculosis with plasma of NHS and ATB patients showed a trend in the reduction of viability of live M. tuberculosis. Moreover, M. tuberculosis pretreated plasma of NHS showed a trend towards an increased spontaneous as well as antigen-induced lymphocyte response when compared to ATB plasma. The enzymatic action of the lysozyme and other enzymes on the cell wall may induce M. tuberculosis to release some antigenic components which may be immunogenic and induce lymphocyte proliferation. The present study suggests that lysozyme and other enzymes may play an important role in the first line defence, i.e. the innate immunity, against M. tuberculosis infection

HLA-DR phenotypes and lymphocyte response to M. tuberculosis antigens and in cured spinal tuberculosis patients and their contacts

Background: Our earlier studies on Human Leucocyte Antigens (HLA) in pulmonary tuberculosis patients revealed the association of HLA-DR2 antigen with susceptibility to pulmonary TB and DR2 antigen has been shown to influence the immunity to tuberculosis. Objectives: The present study was carried out to find out whether HLA-DR antigens are associated with susceptibility to spinal tuberculosis. Moreover, the role of HLA-DR antigens on lymphoproliferative response to Mycobacterium tuberculosis culture filtrate antigens was studied using Lymphocyte Transformation Test (LTT). Material and Methods: HLA-DR genotyping and lymphoproliferative response was carried out in 63 cured spinal TB patients and 63 control subjects (spouses of pulmonary and spinal TB patients). Results: A trend towards an increased frequency of HLA-DR9 antigen was observed in spinal TB patients compared to controls. A significantly decreased lymphocyte response to M. tuberculosis antigens was observed in HLA-DR9 antigen positive control subjects compared to HLA- DR9 antigen negative subjects (P=0.0009) whereas increased response was observed with DR9 positive cured spinal TB patients compared to HLA-DR9 antigen negative patients. Further, HLADR3 antigen positive patients showed a decreased lymphocyte response compared to HLA-DR3 antigen negative patients (P<0.05). Conclusion: The study suggests that HLA-DR9 antigen either alone or in combination with other HLA antigen as lhplotype and non-HLA genes may be associated with susceptibility to spinal TB and play a regulatory role on the immune response to M. tuberculosis in spinal tuberculosis patients

Rigidity and Non-recurrence along Sequences

Two properties of a dynamical system, rigidity and non-recurrence, are examined in detail. The ultimate aim is to characterize the sequences along which these properties do or do not occur for different classes of transformations. The main focus in this article is to characterize explicitly the structural properties of sequences which can be rigidity sequences or non-recurrent sequences for some weakly mixing dynamical system. For ergodic transformations generally and for weakly mixing transformations in particular there are both parallels and distinctions between the class of rigid sequences and the class of non-recurrent sequences. A variety of classes of sequences with various properties are considered showing the complicated and rich structure of rigid and non-recurrent sequences

Association of vitamin D receptor gene variants of BsmI, ApaI and FokI polymorphisms with susceptibility or resistance to pulmonary tuberculosis

Vitamin D receptor (VDR) gene polymorphism was studied to find out whether the variants of this gene are associated with susceptibility or resistance to pulmonary tuberculosis (PTB) and bacteriological relapse of tuberculosis. BsmI, ApaI and FokI polymorphisms of VDR gene were studied in PTB patients (n = 120), patient contacts (spouses of the patients; n = 80), bacteriological relapse patients (n = 48) and quiescent patients (n = 48). Significant increase of Bb genotype (heterozygote carrier) of BsmI polymorphism (P = 0.028) and FF genotype (homozygotes of common allele F) of FokI polymorphism (P = 0.034) were observed in male PTB patients than male contacts. The BB genotype (homozygote of common allele B) of BsmI polymorphism and AA genotype (homozygote of common allele A) of ApaI polymorphism were increased in male contacts than male PTB patients (BB: P = 0.018; AA: P = 0.04). No significant differences were found among female patients and female contacts. In bacteriological relapse cases of PTB, a decreased frequency of AA genotype (P = 0.015) and an increased frequency of Aa genotype (P = 0.024) were observed in bacteriological relapse patients than quiescent patients of PTB. The present study suggests that Bb genotype of BsmI polymorphism and FF genotype of FokI polymorphism of VDR gene may be associated with the susceptibility to tuberculosis in males. The BB and AA genotypes may be associated with resistance to PTB in males. The genotype Aa may be associated with bacteriological relapse and AA may be associated with protection against bacteriological relapse

Dynamical effects of the nanometer-sized polarized domains in Pb(Zn1/3Nb2/3)O3

Recent neutron scattering measurements performed on the relaxor ferroelectric Pb[(Zn1/3Nb2/3)0.92Ti0.08]O3 (PZN-8%PT) in its cubic phase at 500 K, have revealed an anomalous ridge of inelastic scattering centered ~0.2 A-1 from the zone center (Gehring et al., Phys. Rev. Lett. 84, 5216 (2000)). This ridge of scattering resembles a waterfall when plotted as a phonon dispersion diagram, and extends vertically from the transverse acoustic (TA) branch near 4 meV to the transverse optic (TO) branch near 9 meV. No zone center optic mode was found. We report new results from an extensive neutron scattering study of pure PZN that exhibits the same waterfall feature. We are able to model the dynamics of the waterfall using a simple coupled-mode model that assumes a strongly q-dependent optic mode linewidth Gamma1(q) that increases sharply near 0.2 A-1 as one approaches the zone center. This model was motivated by the results of Burns and Dacol in 1983, who observed the formation of a randomly-oriented local polarization in PZN at temperatures far above its ferroelectric phase transition temperature. The dramatic increase in Gamma1 is believed to occur when the wavelength of the optic mode becomes comparable to the size of the small polarized micro-regions (PMR) associated with this randomly-oriented local polarization, with the consequence that longer wavelength optic modes cannot propagate and become overdamped. Below Tc=410 K, the intensity of the waterfall diminishes. At lowest temperatures ~30 K the waterfall is absent, and we observe the recovery of a zone center transverse optic mode near 10.5 meV.Comment: 8 pages, 9 figures (one color). Submitted to Physical Review

Immune response to Mycobacterium tuberculosis culture filtrate antigen in cured spinal tuberculosis patients and their spouses

Humoral and cell mediated immune responses were studied in cured spinal tuberculosis patients and their spouses to understand immunit to tuberculosis in cured patients. Antibody litre and immune complex levels were measured and lymphocyte response to Mycobaclerinm tuberculosis culture filtrate antigen was observed in cured spinal tuberculosis patients ( n = 3 0 ) and their spouses (n =27). A trend towards increased antibody litre was seen in cured patients as compared to their spouses. Significantly increased circulating immune complex levels, as measured by PEG OD280 (polyethylene glycol optical density 280) were seen in the contacts compared to cured patients. And a trend towards increased lymphocyte response to Mtuberculosis culture filtrate antigen was seen with different antigen concentrations (0.1,1 and 10 μg /ml). Moreover, the effect of active-pulmonary-Tuberculosis (AT B) plasma taken from 1ILA-DR2 positive and DR2 negative patients on lymphocyte response of the cured patients showed no dramatic immunomodulatory effect in the lymphocyte response when treated with DR2 positive or DR2 negative plasma. The study suggests that the memory response lo Mtuberculosis is well maintained even after 10-15 years of treatment

Strong Influence of the diffuse component on the lattice dynamics in Pb(Mg1/3_{1/3}Nb2/3_{2/3})O3_{3}

The temperature and zone dependence of the lattice dynamics in Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$ is characterized using neutron inelastic scattering. A strong correlation between the diffuse and phonon scattering is measured. The lattice dynamics in Brillouin zones where the diffuse scattering is strong is observed to display qualitatively different behavior than those zones where the diffuse scattering is weak. In the (220) and (200) zones, where there is a weak diffuse component, the dynamics are well described by coupled harmonic oscillators. Compared with SrTiO$_{3}$, the coupling is weak and isotropic, resulting in only a small transfer of spectral weight from one mode to another. A comparison of the scattering in these zones to the (110) zone, where a strong diffuse component is present, reveals a strong coupling of the diffuse (or central) component to the acoustic mode. We speculate that the coupling to the central peak is the reason for several recent conflicting interpretations of the lattice dynamics based on data from zones with a strong diffuse component.Comment: 7 pages, 7 figure

Soft Phonon Anomalies in the Relaxor Ferroelectric Pb(Zn_1/3Nb_2/3)_0.92Ti_0.08O_3

Neutron inelastic scattering measurements of the polar TO phonon mode dispersion in the cubic relaxor Pb(Zn_1/3Nb_2/3)_0.92Ti_0.08O_3 at 500K reveal anomalous behavior in which the optic branch appears to drop precipitously into the acoustic branch at a finite value of the momentum transfer q=0.2 inverse Angstroms, measured from the zone center. We speculate this behavior is the result of nanometer-sized polar regions in the crystal.Comment: 4 pages, 4 figure

A Neutron Elastic Diffuse Scattering Study of PMN

We have performed elastic diffuse neutron scattering studies on the relaxor Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$ (PMN). The measured intensity distribution near a (100) Bragg peak in the (hk0) scattering plane assumes the shape of a butterfly with extended intensity in the (110) and (1$\bar{1}$0) directions. The temperature dependence of the diffuse scattering shows that both the size of the polar nanoregions (PNR) and the integrated diffuse intensity increase with cooling even for temperatures below the Curie temperature $T_C \sim 213$ K.Comment: Submitted to PR

A Universal Phase Diagram for PMN-xPT and PZN-xPT

The phase diagram of the Pb(Mg1/3Nb2/3)O3 and PbTiO3 solid solution (PMN-xPT) indicates a rhombohedral ground state for x < 0.32. X-ray powder measurements by Dkhil et al. show a rhombohedrally split (222) Bragg peak for PMN-10%PT at 80 K. Remarkably, neutron data taken on a single crystal of the same compound with comparable q-resolution reveal a single resolution-limited (111) peak down to 50 K, and thus no rhombohedral distortion. Our results suggest that the structure of the outer layer of these relaxors differs from that of the bulk, which is nearly cubic, as observed in PZN by Xu et al.Comment: Replaced Fig. 3 with better versio