Antigens of Mycobacterium leprae in the cerebrospinal fluid of leprosy patients: detection by monoclonal-antibody-based sandwich immunoradiometric assay and avidin/biotin immunoblotting.

Mycobacterium leprae antigens could be detected in the cerebrospinal fluid (CSF) of patients with leprosy, using a monoclonal-antibody-based sandwich immunoradiometric assay (SIRMA). Antigens of 12 kD, 35 kD and 30-40 kD were detected using ML06, ML04, and ML34 monoclonal antibodies, respectively. The 30-40-kD polysaccharide antigen, although present in larger amounts in M. leprae than the 12-kD and 35-kD protein antigens, was found in the CSF of comparatively fewer subjects. The antigen capture assay has been found sensitive to the level of nanograms. Avidin-biotin-based immunoblotting using pooled leprosy sera detected a larger number of antigens than using anti-M. leprae antisera raised in rabbits. The immunoblotting of CSF samples revealed about three antigens in the region of 100-160 kD and three more in the region of 45-60 kD as probed by leprosy sera. This study has for the first time revealed the presence of M. leprae antigens in the CSF of leprosy patients and the probable involvement of the central nervous system in leprosy.     

Direct detection and identification of Mycobacterium tuberculosis and Mycobacterium bovis in bovine samples by a novel nested PCR assay: correlation with conventional techniques

Mycobacterium tuberculosis and M. bovis infect animals and humans. Their epidemiologies in developed and developing countries differ, owing to differences in the implementation of preventive measures (World Health Organization, 1999). Identification and differentiation of these closely related mycobacterial species would help to determine the source, reservoirs of infection, and disease burden due to diverse mycobacterial pathogens. The utility of the hupB gene (Rv2986c in M.tuberculosis, or Mb3010c in M.bovis) to differentiate M. tuberculosis and M. bovis was evaluated by a PCR-restriction fragment length polymorphism (RFLP) assay with 56 characterized bovine isolates (S. Prabhakar et al., J. Clin. Microbiol. 42:2724-2732, 2004). The degree of concordance between the PCR-RFLP assay and the microbiological characterization was 99.0% (P < 0.001). A nested PCR (N-PCR) assay was developed, replacing the PCR-RFLP assay for direct detection of M. tuberculosis and M. bovis in bovine samples. The N-PCR products of M. tuberculosis and M. bovis corresponded to 116 and 89 bp, respectively. The detection limit of mycobacterial DNA by N-PCR was 50 fg, equivalent to five tubercle bacilli. M. tuberculosis and/or M. bovis was detected in 55.5% (105/189) of the samples by N-PCR, compared to 9.4% (18/189) by culture. The sensitivities of N-PCR and culture were 97.3 and 29.7, respectively, and their specificities were 22.2 and 77.7%, respectively. The percentages of animals or samples identified as infected with M.tuberculosis or M. bovis by N-PCR and culture reflected the clinical categorizations of the cattle (P of <0.05 to <0.01). Mixed infection by N-PCR was detected in 22 animals, whereas by culture mixed infection was detected in 1 animal.     

Analysis of quantitative relationship between viability determination in leprosy by MFP,ATP bioluminescence and gene amplification assay

Two hundred twenty-one untreated, borderline lepromatous/lepromatous (BL/LL) leprosy patients have been investigated for viability by the mouse foot pad method (MFP), adenosine triphosphate (ATP) and polymerase chain reaction (PCR). The biopsies were collected at the beginning of and 12/24 months after treatment. The patient group was treated with a) immunotherapy (BCG/Mw) + MDT; b) MDT + pyrazinamide; c) control MDT; d) MDT + minocycline 100 mg once a month supervised + ofloxacin 400 mg once a month supervised. Biopsies were divided in three parts for use in the mouse foot pad, molecular and ATP investigations. In untreated and treated patients (at 12 and 24 months), there was a general agreement among all three techniques, and PCR and ATP showed higher positivity as compared to MFP. Further, there was good correlation among the viable biomass estimated by bacillary ATP levels, PCR assay and growth in mouse foot pads. The positivity was observed by MFP as well as PCR assay (18-kDa and 36-kDa) from all of the specimens when the ATP content was more than 3.6 pg/million. When the ATP content was below 3.5 pg/million, the positive takes in MFP decreased but the PCR positivity correlated with ATP bioluminescence up to 0.04 pg/million. When the ATP content was even lower, the uptake in the MFP was possibly a matter of chance, while PCR positivity was observed in 96% of the cases. For specimens with undetectable ATP, positivity was seen in 1% of the cases, showing the inability of ATP bioluminescence method to detect low background due to host ATP. PCR signals in some cases could be due to the higher sensitivity of the method or persistence of DNA after bacterial death in some cases. On the whole, the PCR methods even though targeting DNA have shown good correlations with biomass which confirm their usefulness in monitoring therapeutic responses in leprosy.     

Post synthetically modified IRMOF-3 for efficient recovery and selective sensing of U(vi) from aqueous medium

A simple and efficient route to develop various novel functionalized MOF materials for rapid and excellent recovery of U(vi) from aqueous medium, along with selective sensing has been demonstrated in the present study. In this connection, a set of four distinct post synthetically modified (PSM) iso-reticular metal organic frameworks were synthesized from IRMOF-3 namely, IRMOF-PC (2-pyridine carboxaldehyde), IRMOF-GA (glutaric anhydride), IRMOF-SMA (sulfamic acid), and IRMOF-DPC (diphenylphosphonic chloride) for the recovery and sensing of U(vi) from aqueous medium. The MOFs were characterized by Fourier transform infrared spectroscopy (FTIR), powder XRD, BET surface area analysis, thermogravimetric analysis (TGA), NMR (¹³C, ¹H and ³¹P), Scanning Electron Microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Among all MOFs, post synthetically modified IRMOF-SMA showed enhanced thermal stability of about 420 °C. The MOFs were investigated for U(vi) sorption studies using a batch technique. All the MOFs exhibit excellent sorption capacity towards U(vi) (>90%) and maximum uptake was observed at pH 6. Sorption capacity of MOFs have the following order; IRMOF-3-DPC (300 mg U g⁻¹) > IRMOF-SMA (292 mg U g⁻¹) > IRMOF-PC (289 mg U g⁻¹) > IRMOF-GA (280 mg U g⁻¹) > IRMOF-3 (273 mg U g⁻¹). IRMOF-DPC shows rapid sorption of uranium within 5 min with excellent uptake of U(vi) (>99%). The desorption of U(vi) was examined with different eluents and 0.01 M HNO₃ was found to be most effective. The fluorescence sensing studies of U(vi) via IRMOF-3 and its PSM MOFs revealed high sensitivity and selectivity towards U(vi) over other competing rare earth metal ions (La³⁺, Ce⁴⁺, Sm³⁺, Nd³⁺, Gd³⁺, and Eu³⁺), wherein IRMOF-GA displayed an impressive detection limit of 0.36 mg L⁻¹ for U(vi).

Four IRMOFs following PSM strategy were prepared. The MOFs were characterized by different techniques and were investigated for U(vi) sorption. PSM MOFs displayed impressive fluorescent sensing and selectivity of U(vi) over competing metal ions.     

An Update on Retinopathy of Prematurity (ROP)

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease affecting the retina of premature infants. The clinical spectrum of ROP varies from spontaneous regression to bilateral retinal detachment and total blindness. Between these two extremes lies the form of ROP, which is amenable to treatment with laser photocoagulation, anti-vascular endothelial growth factor drugs or surgery. Increasing rates of preterm births coupled with better survival rates but lack of uniform quality of neonatal care and delays in diagnosis have led to increasing ROP blindness. Atypical forms of Aggressive Posterior ROP are seen in heavier birth weight babies in developing countries. Prevention of ROP by following stringent protocols for supplemental oxygen, prevention of sepsis, timely screening and laser treatment by a concerted and collaborative effort of neonatologists and ophthalmologists are required to fight the blindness from ROP.     

Warfare vascular injuries

Vascular injuries as a part of combat injuries have been recorded since times immemorial. Responsible for death due to exsanguination, the management of vascular injuries was ligation or amputation till the landmark Vietnam experience. The present day management has evolved with advances in modern technology and may start at the battlefield with the application of a tourniquet with the definitive treatment continuing beyond the combat operation theatres. A basic understanding of both blunt and penetrating vascular injuries will help minimize mortality and morbidity.