ABSTRACT
PURPOSE: This study compares the results of radiorespirometric Buddemeyer assay with adenosine triphosphate (ATP) assay and mouse foot pad (MFP) test to validate the sensitivity of Buddemeyer assay in detecting viable M. leprae in clinical samples. METHODS: Viability was assessed using all the three methods in 60 skin biopsy specimens, including 20 untreated lepromatous leprosy (BL-LL), 13 treated BL-LL, 12 untreated borderline tuberculoid to mid borderline (BT-BB) and 15 treated BT-BB cases. RESULTS: Of the 20 untreated BL-LL cases tested, positivity indicating the presence of viable M. leprae was detected in 85, 60 and 85% with Buddemeyer, ATP and MFP test, respectively. Among the 13 treated BL-LL cases, scores were 61, 54 and 0%; among the 12 untreated BT-BB cases, the scores were 58, 16 and 16% and among the 15 treated BT-BB cases, the scores were 46, 20, 0%, respectively. CONCLUSION: The detection sensitivity (positive scores) with three tests were closely comparable in the two untreated groups of cases. On the other hand, in the two treated groups, a good proportion of cases scored positive in the in vitro tests but none in the MFP test. Among the two in vitro methods, the Buddemeyer assay emerged as a better test, in terms of sensitivity and specificity.
Subject(s)
Adenosine Triphosphate/metabolism , Animals , Carbon Dioxide/metabolism , Carbon Radioisotopes/metabolism , Disease Models, Animal , Humans , Leprosy/diagnosis , Mice , Microbial Viability , Mycobacterium leprae/isolation & purification , Sensitivity and SpecificityABSTRACT
Thirty lepromatous (BL-LL) and 25 tuberculoid (TT-BT) nerve lesions obtained from untreated cases of leprosy were scanned using transmission electron microscope for assessing the bacterial load in different cell types. Major bulk of infection was seen in the Schwann cells of nonmyelinated fibres, in both early lepromatous and tuberculoid nerve lesions, suggesting that M. leprae spread mainly via the Schwann cells within the nerve.
Subject(s)
Colony Count, Microbial , Humans , Leprosy, Lepromatous/microbiology , Leprosy, Tuberculoid/microbiology , Microscopy, Electron , Mycobacterium leprae/isolation & purification , Nerve Fibers/microbiologyABSTRACT
Various mechanisms for nerve damage in tuberculoid leprosy have been proposed. A common feature amongst them is the crucial role played by T-cells. Therefore, the present study was designed to determine the role of T-cells in the induction of nerve damage in leprosy using two different protocols for obtaining graded levels of T-cell depletion: (i) Cyclosporine A, for depletion of T-helper cells and (ii) Anti Thy 1.2, for total depletion of T-cells. The findings indicate that the early changes seen in the unmyelinated fibres may not involve T-cells. However, the later stages of nerve damage associated with demyelination are dependent on T-cell responses.
Subject(s)
Animals , Cyclosporine/pharmacology , Demyelinating Diseases/etiology , Female , Isoantibodies/immunology , Leprosy/microbiology , Mice , Mycobacterium leprae/growth & development , Sciatic Nerve/pathology , T-Lymphocytes/physiologyABSTRACT
Intracellular localization of antileprosy drugs dapsone (DDS) and rifampicin (RFP) was carried out on skin and nerve lesions obtained from multidrug treated, multi (BL-LL)- and pauci (BT-TT) bacillary cases of leprosy using immunocytochemical techniques. Intracellular localization of the above drugs especially in macrophages and Schwann cells was aimed by using rabbit raised anti DDS and RFP polyclonal antibody in an indirect peroxidase assay. Our study records both intra and extracellular staining with anti DDS and RFP antibodies in the skin as well as nerve lesions of MB and PB cases treated with MDT. All the nerves under investigation had moderate to severe pathology and hence free diffusion of the drug could be attributed to the broken barrier. Basal lamina around the Schwann cell did not seem to form a barrier. It was also noted that the drug (metabolite) persisted over a long period of time).
Subject(s)
Animals , Dapsone/analysis , Humans , Immunoenzyme Techniques , Leprostatic Agents/analysis , Leprosy/drug therapy , Macrophages/metabolism , Mice , Nerve Tissue/metabolism , Rabbits , Rifampin/analysis , Schwann Cells/metabolism , Skin/metabolismABSTRACT
Ultrastructural changes in the mouse dorsal root ganglion cultures infected long-term with viable M.leprae were studied. Subtle cytomorphological changes and loss of neurites noted in the long-term infected cultures were correlated to early events in the nerve damage.
Subject(s)
Animals , Cells, Cultured , Ganglia, Spinal/microbiology , Leprosy/pathology , MiceABSTRACT
Effect of DDS was studied using the mouse model. It was observed that DDS did not have any neurotoxic effect. On the contrary it showed a protective action towards the nerve, when administered in the early stages following definite establishment of nerve lesions.