3,661 research outputs found
Madras study of short-course chemotherapy in pulmonary tuberculosis
This article presents the results of a controlled clinical study of 3 shortcourse regimens conducted
at the Tuberculosis Research Centre, Madras, in collaboration with the British Medical Research
Council and the World Health Organization
Relapse in tuberculosis
At the outset, I would like to express my sincere gratitude to the Tuberculosis Association of India for having bestowed upon the coveted Wander-TAI Oration Award. When I think of the illustrious personalities who have preceded me I began to have doubts as to whether I will be able to do justice to today's occasion. If I fail to come up to your expectations it will not be because of lack of honest efforts on my part - it is because I neither have the scientific stature nor the gray hairs which my predecessors had. I sincerely hope you will view it in the proper spirit and condone any lapses in my presentation.
We are about to celebrate the centenary of the discovery of the tubercle bacilli by Robert Koch. It is less than 4 decades since we have had the benefits of chemotherapeutic agents with specific activity against tuberculosis. Nevertheless, the decades following the discovery of streptomycin by Waksman in 1943 have seen spectacular achievements in chemotherapy of tuberculosis. We now have several anti-tuberculosis drugs - isoniazid, rifampicin, streptomycin, pyrazinamide, PAS, ethambutol, thioacetazone, ethionamide, and a few other drugs. Isoniazid is by far the most potent and most effective drug with a bacteriological activity, with rifampicin being a close second. Streptomycin and pyrazinamide also have bactericidal activity, and like isoniazid and rifampicin, cause death of tubercle bacilli. Drugs such as PAS, ethambutol and thioacetazone have a bacteriostatic activity, that is, they prevent the multiplication of the bacilli, so that the elimination of the bacilli would depend upon the defense mechanism of the host; their utility is limited to their being companion drugs given in combination with isoniazid with the object of preventing the multiplication of isoniazid-resistant mutants. The present day management of tuberculosis consists of treatment with a combination of isoniazid with at least one other drug in appropriate dosages and rhythms for periods upto 24 months. With a judicatious choice of drug regimens containing isoniazid and other drugs it is possible to produce rapid sputum conversion to negativity and to eliminate the possibility of emergence of drug-resistance; further, patients attaining bacteriological quiescence continue to have quiescent disease even after stopping chemotherapy. With inadequate chemotherapy, on the other hand, failures may manifest in one or more ways - sputum may fail to become culture negative, drug-resistance may emerge, or sputum conversion occurs during treatment but culture becomes positive again after treatment is discontinued, that is, the patient has a bacteriological relapse. With the advent of highly effective chemotherapeutic regimens with practically 100% efficacy, bacteriological relapse has become the most crucial factor in determining the relative merits of chemotherapeutic regimens. I have, therefore, chosen the subject of relapse for today's oration
Short-course chemotherapy of pulmonary tuberculosis
The last four decades have seen spectacular developments in the management of pulmonary tuberculosis. The discovery of streptomycin in 1943 by Waksman was soon followed by other drugs with anti-tuberculosis activity, such as PAS, isoniazid, pyrazinamide, thioacetazone, ethambutol, rifampicin and others. The dis-covery of the anti-tuberculosis activity of isonia-zid in 1952 was a great land-mark which re-volutionalised the treatment of tuberculosis. Because of its high efficacy, low toxicity and low cost, isoniazid soon became the drug of choice in tuberculosis. Administered alone daily for 12 months, it has a potential of producing bacteri-ological quiescence in approximately 70% of pulmonary tuberculosis cases excreting isoniazid-sensitive cultures in their sputum. The con-comitant administration of thioacetazone or PAS daily for 1 year increases the efficacy of the regimen to about 85%. However, approximately 20% of the patients with quiescent disease at 1 year have a bacteriological relapse after stopping chemotherapy, so that the overall efficacy of the 2-drug regimens is reduced to less than 70% even among those patients who consume the drugs regularly. Such relapses can be prevented by continuing chemotherapy beyond 12 months for another 6-12 months. It is, therefore, customary to prescribe regimens of 8-24 months to tuberculosis patients
Axially magnetized Dark Energy cosmological model
We investigate the behaviour of the skewness parameters for an anisotropic
universe in the framework of General Relativity. Non interacting dark energy is
considered in presence of electromagnetic field. A time varying deceleration
parameter simulated by a hybrid scale factor is considered. The dynamics of the
universe is investigated in presence and absence of magnetic field. The
equation of state parameter of dark energy evolves within the range predicted
by the observations. Magnetic field is observed to have a substantial effect on
the cosmic dynamics and the skewness parameters. The models discussed here end
in a big rip and become isotropic at finite time.Comment: 9 pages, 13 figures, Version accepted for publication in Mod. Phys.
Lett.
Azimuthal correlations of D-mesons in + and +Pb collisions at LHC energies
We study the correlations of D mesons produced in + and +Pb
collisions. These are found to be sensitive to the effects of the cold nuclear
medium and the transverse momentum () regions we are looking into. In
order to put this on a quantitative footing, as a first step we analyse the
azimuthal correlations of D meson-charged hadron(Dh), and then predict the same
for D meson -anti D meson () pairs in + and +Pb
collisions with strong coupling at leading order ()
and next to leading order () which includes space-time
evolution (in both systems), as well cold nuclear matter effects (in +Pb).
This also sets the stage and baseline for the identification and study of
medium modification of azimuthal correlations in relativistic collision of
heavy nuclei at the Large Hadron Collider.Comment: 12 pages, 4 figure
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