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.     

Mutations in VMK1, a mitogen-activated protein kinase gene, affect microsclerotia formation and pathogenicity in Verticillium dahliae

Verticillium dahliae is an important soil-borne fungal pathogen that causes vascular wilt diseases in a large variety of important crop plants. Due to its persistence in the soil, control of Verticillium wilt relies heavily on soil fumigation. The global ban on methyl bromide, a highly effective soil fumigant, poses an urgent need to develop alternative control measures against Verticillium wilt; and these might be more forthcoming with a better understanding of the molecular and cellular mechanisms that underpin the pathogenicity of V. dahliae. In this study, we assessed the role in growth, development, and pathogenicity of VMK1, a gene encoding a mitogen-activated protein (MAP) kinase (hence, Verticillium MAP Kinase 1). Disruption of VMK1 via Agrobacterium tumefaciens-mediated transformation, in two V. dahliae isolates, one from lettuce and the other from tomato, resulted in severely reduced virulence in diverse host plants, suggesting that VMK1 is essential for pathogenicity and that the MAP kinase-mediated signaling pathway has a conserved role in fungal pathogenicity. The vmk1 mutants also exhibited reduced conidiation and microsclerotia formation, suggesting that the gene is important for multiple cellular processes. P.R. and R.G.B. equally contributed to the work     

A critical function for type I interferons in cancer immunoediting

'Cancer immunoediting' is a process wherein the immune system protects hosts against tumor development and facilitates outgrowth of tumors with reduced immunogenicity. Although interferon-gamma (IFN-gamma) is known to be involved in this process, the involvement of type I interferons (IFN-alpha/beta) has not been elucidated. We now show that, like IFN-gamma, endogenously produced IFN-alpha/beta was required for the prevention of the growth of primary carcinogen-induced and transplantable tumors. Although tumor cells are important IFN-gamma targets, they are not functionally relevant sites of the actions of the type I interferons. Instead, host hematopoietic cells are critical IFN-alpha/beta targets during development of protective antitumor responses. Therefore, type I interferons are important components of the cancer immunoediting process and function in a way that does not completely overlap the functions of IFN-gamma.     

New image-processing system for analysis,display and measurement of static and dynamic foot pressures

A new image-processing system, using a video digitiser with an IBM-compatible PC/AT, is developed for acquisition and processing of low-contrast, lowintensity barographic images of both feet for assessment of pressure distribution during standing and walking. Data displays, in the form of centres of pressures, isopressures contours, perspective views of pressures, grey scale image and walking pressure patterns, combined image of walking pressures, paths of centres of pressures and pressure variations with time, are developed. These have provided very useful and early information regarding the internal structural changes in the bones of the foot and sites at risk of ulcer development in leprosy subjects and enable suitable corrective orthopaedic procedures to be adopted. unitl the end of November 1990, and will then return to the Indian Institute of Technology.     

Genomic DNA insertions and deletions occur frequently between humans and nonhuman primates

Comparative DNA sequence studies between humans and nonhuman primates will be important for understanding the genetic basis of the phenotypic differences between these species. Here we compare approximately 27 Mb of human chromosome 21 with chimpanzee DNA sequences identifying 57 genomic rearrangements (deletions and insertions ranging in size from 0.2 to 8.0 kb) between the two species. These rearrangements are distributed along the entire length of chromosome 21, with approximately 35% found in genomic intervals encoding genes (genic intervals), and have occurred in the genomes of both humans and chimpanzees. Comparison of approximately 9 Mb of human chromosome 21 with orangutan, rhesus macaque, and woolly monkey DNA sequences identified a combined total of 114 genomic rearrangements between humans and nonhuman primates. Analysis of these rearrangements revealed that they are randomly distributed with respect to genic and nongenic intervals and identified one deletion that has likely resulted in the inactivation of a gene (beta1,3-galactosyltransferase) in the woolly monkey. Our data show that genomic rearrangements have occurred frequently during primate genome evolution and significantly contribute to the DNA differences between these species. These DNA rearrangements are commonly found in genic intervals, and thus provide natural starting points for focused investigations of qualitative and quantitative gene expression differences between humans and other primates.     

Detection of hepatitis B antibody by a single-antibody radioimmunoassay.

A radioimmunoassay (RIA) for the measurement of antibody to hepatitis B surface antigen (anti-HB-s) in human and non-human sera is described. The principle is based upon our earlier observation that anti-HB-s and hepatitis B surface antigen (HB-s-Ag) are soluble in 4.5% w/v polyethylene glycol 4000 but that anti-HB-s-HB-s-Ag complex is precipitated. The use of activated charcoal suspended in polyethylene glycol and dextran solution facilitated the separation of this complex by centrifugation, thus improving reproducibility and sensitivity. The test is approx. 3-5000 times as sensitive as counterelectrophoresis. In a survey of a normal blood donor population, with an incidence of approx. 0.1% positive for HB-s-Ag by RIA, 7-8% were found to have anti-HB-s by this method.     

Gross and cellular analysis of 6-mercaptopurine-induced cleft palate in hamster

The present study analyzes the morphological, histochemical, and ultrastructural aspects of the pathogenesis of 6-mercaptopurine (6MP)-induced cleft palate in hamster fetuses. Gross and light microscopic observations indicated that 6MP stunts the growth of vertical palatal shelves and thus induces cleft palate. Ultrastructural analysis showed that, in contrast to controls, 6MP-induced alterations were first seen in the mesenchymal cells 24 hr after drug administration. The initial alterations were characterized by swelling of the nuclear membrane. During the next 12 hr, lysosomes were seen first in the mesenchymal cells and then in the cells of the medial edge epithelium (MEE) of the developing palatal primordia. The appearance of lysosomes was temporally abnormal and was interpreted as a sublethal response to 6MP treatment. Subsequently, the nuclear alterations and the lysosomes diminished; and 48 hr after 6MP administration, they were absent from the palatal tissues. Ninety hours after 6MP administration, unlike the controls (in which the palatal shelves were already fused), changes were seen at the epithelial-mesenchymal interface in the developing cleft palatal shelves. These changes were characterized by breakdown of the basal lamina and epithelial-mesenchymal contacts. Eventually, at term, the MEE of the vertical shelf stratified. It was suggested that 6MP affected cytodifferentiation in the palatal tissues during the critical phase of early vertical shelf development and thereby induced cleft palate.     

Double Electroconvulsive Therapy for Resistant Depression

A case is described of psychotic depression that worsened during a course of three bilateral ECTs per week, but responded to administration of two bilateral ECTs three times per week. For some patients, ECTs may need to be given more than three times per week to obtain remission.