We test Lowenstein's dc bias hypothesis as an alternative mechanism for the phenomenon sometimes called 'stochastic resonance'. Probe stimuli consisting of paired phase-locked tones at frequencies f(1) and f(2) (where f(2)-f(1)=800 Hz, f(1)>4.5 kHz) and at equal intensity were used to generate synchronous 800 Hz cochlear nerve activity (envelope responses). When a background tone of the same in...

BACKGROUND Lymphadenitis is common in HIV-positive patients. Diagnosis of the infections associated with this condition is complex, particularly in the case of tuberculosis. Rapid and specific detection of Mycobacterium tuberculosis (M. tuberculosis) is fundamental in ensuring adequate treatment. In addition, frequent causes of lymphadenitis such as those associated with lymphoma and histoplasm...

BACKGROUND To compare Bactec MGIT 960 with LJ media in terms of time taken for the initial isolation of mycobacteria. METHODS A total of 100 AFB (acid fast bacillus) positive sputum samples were processed and inoculated in both the Lowenstein Jensen (LJ) media and mycobacterium growth indicator tube (MGIT) tubes. RESULTS Of the 100 samples, positive growth was obtained from all the samples ...

Method: One hundred thirty tuberculosis suspected individuals of both sexes and of different ages were included in the study. Sputum samples were cultured on Lowenstein-Jensen (LJ) medium. Resistant strains were tested for the presence of mutations conferring resistance using molecular techniques to amplify 315 base pair (bp) rifampicin (RIF) and 146 bp isoniazid (INH), as markers for MDR among...

We evaluated four decontamination methods and one nondecontamination procedure in combination with four egg-based media for the primary isolation of Mycobacterium ulcerans from tissue specimens. With mycobacterial recovery and contamination rates of 75.6 and 2.4%, respectively, the combination of the oxalic acid decontamination method with Lowenstein-Jensen medium supplemented with glycerol yie...

Pyrazinamide (PZA) is an important first-line antituberculosis drug because of its sterilizing activity against semidormant tubercle bacilli. In spite of its very high in vivo activity, its in vitro activity is not apparent unless an acidic environment is available, which makes PZA susceptibility testing difficult by conventional methods. The present study was, therefore, planned to assess the ...

Tuberculosis a contagious and airborne disease affecting mostly young adults in their most productive years. The vast majority of tuberculosis deaths are in the developing world, so called a disease of poverty (1). Tuberculosis can involve any organ system in the body. Extrapulmonary tuberculosis comprises 10-50% of all tuberculosis in HIV negative patients and about 35-80% in HIV infected pati...

The BACTEC MGIT 960 instrument is a fully automated system that exploits the fluorescence of an oxygen sensor to detect growth of mycobacteria in culture. Its performance was compared to those of the radiometric BACTEC 460 instrument and egg-based Lowenstein-Jensen medium. An identical volume of sample was inoculated in different media, and incubation was carried out for 6 weeks with the automa...

Methods are now available which are sensitive enough to detect digoxin concentration to levels of 5 mug./ml. Hitherto the degree of sensitivity of specific chemical methods was not acceptable for clinical application. Digoxin-specific antibodies have recently been prepared (Butler and Chen, 1967), and a test based on the radioimmunoassay principle has now been used to measure plasma digoxin lev...