Leprosy in a prison population: A new active search strategy and a prospective clinical analysis

BackgroundThis study evaluates an active search strategy for leprosy diagnosis based on responses to a Leprosy Suspicion Questionnaire (LSQ), and analyzing the clinical, immunoepidemiological and follow-up aspects for individuals living in a prison population.MethodsA cross-sectional study based on a questionnaire posing 14 questions about leprosy symptoms and signs that was distributed to 1,400 prisoners. This was followed by dermatoneurological examination, anti-PGL-I serology and RLEP-PCR. Those without leprosy were placed in the Non-leprosy Group (NLG, n = 1,216) and those diagnosed with clinical symptoms of leprosy were placed in the Leprosy Group (LG, n = 34).FindingsIn total, 896 LSQ were returned (64%), and 187 (20.9%) of the responses were deemed as positive for signs/symptoms, answering 2.7 questions on average. Clinically, 1,250 (89.3%) of the prisoners were evaluated resulting in the diagnosis of 34 new cases (LG), based on well-accepted clinical signs and symptoms, a new case detection rate of 2.7% within this population, while the NLG were comprised of 1,216 individuals. The confinement time medians were 39 months in the LG while it was 36 months in the NLG (p>0.05). The 31 leprosy cases who responded to the questionnaire (LSQ+) had an average of 1.5 responses. The symptoms “anesthetized skin area” and “pain in nerves” were most commonly mentioned in the LG while “tingling, numbness in the hands/feet”, “sensation of pricks and needles”, “pain in nerves” and “spots on the skin” responses were found in more than 30% of questionnaires in the NLG. Clinically, 88.2% had dysesthetic macular skin lesions and 97.1% presented some peripheral nerve impairment, 71.9% with some degree of disability. All cases were multibacillary, confirming a late diagnosis. Anti-PGL-I results in the LG were higher than in the NLG (p<0.0001), while the RLEP-PCR was positive in 11.8% of the patients.InterpretationOur findings within the penitentiary demonstrated a hidden prevalence of leprosy, although the individuals diagnosed were likely infected while living in their former communities and not as a result of exposure in the prison. The LSQ proved to be an important screening tool to help identify leprosy cases in prisons.     

Transposition is modulated by a diverse set of host factors in Escherichia coli and is stimulated by nutritional stress

The role of host factors in regulating bacterial transposition has never been comprehensively addressed, despite the potential consequences of transposition. Here, we describe a screen for host factors that influence transposition of IS903, and the effect of these mutations on two additional transposons, Tn10 and Tn552. Over 20,000 independent insertion mutants were screened in two strains of Escherichia coli; from these we isolated over 100 mutants that altered IS903 transposition. These included mutations that increased or decreased the extent of transposition and also altered the timing of transposition during colony growth. The large number of gene products affecting transposition, and their diverse functions, indicate that the overall process of transposition is modulated at many different steps and by a range of processes. Previous work has suggested that transposition is triggered by cellular stress. We describe two independent mutations that are in a gene required for fermentative metabolism during anaerobic growth, and that cause transposition to occur earlier than normal during colony development. The ability to suppress this phenotype by the addition of fumarate therefore provides direct evidence that transposition occurs in response to nutritional stress. Other mutations that altered transposition disrupted genes normally associated with DNA metabolism, intermediary metabolism, transport, cellular redox, protein folding and proteolysis and together these define a network of host proteins that could potentially allow readout of the cell's environmental and nutritional status. In summary, this work identifies a collection of proteins that allow the host to modulate transposition in response to cell stress.     

VIRUS-LIKE PARTICLES AND NUCLEAR INCLUSIONS IN THE RED ALGA PORPHYRIDIUM PURPUREUM (BORY) DREW ET ROSS1

Ultrastructural examination of the unicellular red alga Porphyridium purpureum has revealed cytoplasmic and nuclear inclusions termed concentrosomes. These bodies are morphologically distinct from the irregular membranous inclusions previously reported by others as concentric bodies. In thin section, the morphology of concentrosomes varies from a simple set of 3 or 4 (or rarely 5) concentrically arranged, electron-opaque, circular profiles to elongate, sinuous forms and particulate aggregations, the majority clearly within the nucleus but separated front the nucleoplasm by what appears to be the nuclear envelope. Although simple concentrosomes may be observed in either the cytoplasm or the nuclei, the more elaborate forms occur only in nuclei. In addition to the concentrosomes, subspherical to polygonal virus-like particles of approximately 40 nm diameter have been observed in P. purpureum. These particles are characterized by an electron-opaque perimeter that, in approximately equal numbers, surrounds an “empty” or an opaque core. Dense arrays of the virus-like particles appear in the cytoplasm but not in the nuclei. Similarities between certain forms of the concentrosomes and the virus-like particles are suggestive of an ontogenetic relationship. The infrequency with which either the concentrosomes or the virus-like particles are observed has hampered attempts to verify a developmental sequence or to establish unequivocally the infectious nature of the virus-like particles.     

Similarity in Several Properties of Psychrophilic Bacteria Grown at Low and Moderate Temperatures

Several properties of psychrophilic pseudomonads were studied with cells grown in batch culture in nutrient broth at 2 and 30 C. No differences were observed in the size, catalase activity, deoxyribonucleic acid, ribonucleic acid, or protein content of cells grown at either temperature. The importance of comparing physiologically similar cells is discussed.     

Characterisation of mutations in 77 patients with X-linked myotubular myopathy,including a family with a very mild phenotype

X-linked myotubular myopathy is characterised by neonatal hypotonia, muscle weakness and respiratory distress in affected males, leading often to early death, although prolonged survival is observed in milder forms, or as a result of prolongation of ventilation support. It is caused by mutations in the MTM1 gene, which encodes a phosphatase called myotubularin, which has been highly conserved during evolution, down to yeasts ( S. cerevisiae and S. pombe). To date, 251 mutations have been identified in unrelated families, corresponding to 158 different disease-associated mutations, which are widespread throughout the gene. We have found additional mutations in 77 patients, including 35 novel ones. We identified a missense mutation N180K in a 67-year-old grandfather (the oldest known patient with an MTM1 mutation), previously suspected to have autosomal centronuclear myopathy, and in his two grandsons also mildly affected. Mild and moderate phenotypes associated with novel missense mutations and with a translation initiation defect mutation are discussed, as well as severe phenotypes associated with particular novel mutations. With the present report, 192 different mutations in the MTM1 gene have been described in 328 families. The spectrum of mutations is now enlarged from the very severe classic neonatal phenotype to very mild phenotype allowing survival to the age of 67 years.     

VSV transmembrane domain (TMD) peptide promotes PEG-mediated fusion of liposomes in a conformationally sensitive fashion

Helical instability induced by gly residues in the transmembrane domain (TMD) of G protein, the fusion protein of vesicular stomatitis virus (VSV), was speculated to aid in the later steps of the fusion process, because G protein with ala's substituted for the two TMD gly's was inactive (Cleverley, D. Z., and Lenard, J. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 3425-30). Here we examine the conformations of synthetic peptides corresponding to fusion-active (GGpep) and inactive (AApep; G's replaced by A's) TMDs by CD spectroscopy, and then their effects on the kinetics of poly (ethyleneglycol) (PEG)-mediated fusion of small unilamellar vesicles. GGpep and AApep both assumed history-dependent, non-interconvertible ordered structures. Both peptides were largely helical under all conditions if derived from trifluoroethanol solutions, and aggregated in a beta-sheet form if derived from acetonitrile solutions. In solvent, detergents or lipid bilayers, GGpep showed a greater range of secondary structural features than did AApep. The two peptides had large but different effects on PEG-mediated fusion. Both enhanced the rate but not the extent of lipid mixing. AApep significantly inhibited the extent of fusion pore formation while GGpep had no effect. The initial rate of fusion was enhanced 6-fold by GGpep and less than 2-fold by AApep. Addition of 5 mol % hexadecane overrode all peptide-induced effects. We suggest that both GGpep and hexadecane promote pore formation by stabilizing the nonlamellar structures in fusion intermediates or initial small pores. AApep, which had fewer nonhelical features in its CD spectrum than GGpep, actually inhibited fusion pore formation.     

Activin signals via SMAD2/3 between germ and somatic cells in the human fetal ovary and regulates kit ligand expression

Ovarian germ cell survival is dependent upon the formation of primordial follicles, which occurs during fetal life in the human. Activin contributes to germ cell proliferation and survival at this time. SMADs2 and 3 are central elements in the activin signalling pathway and thus indicate sites of activin action. We have investigated the expression and localisation of SMADs2 and 3 in the fetal ovary between 14 and 20 weeks gestation, i.e. preceding and during primordial follicle formation. SMAD3 mRNA expression increased 1.9 fold (P = 0.02). SMAD2 and 3 proteins were localised by immunofluorescence to the nuclei of three distinct populations of somatic cells: (a) stromal cells between clusters of germ cells; (b) some somatic cells intermingled with activin βA-expressing germ cells; (c) pre-granulosa cells surrounding primordial follicles. Germ cells did not express SMAD2 or 3. Activin A increased and follistatin decreased phosphorylation of SMAD2/3 in vitro, and activin increased SMAD2 and decreased KITLG mRNA expression. It therefore appears that somatic cells are the targets for activin signalling in the developing ovary. The effects of activin on germ cells are indirect and include mediation by the kit ligand/c-Kit pathway, rather than being an autocrine germ cell effect.     

High-performance thin-layer chromatography-bioautography for multiple antibiotic residues in cow's milk

An analytical method to identify and quantify multiple antibiotic residues (chloramphenicol, ampicillin, benzylpenicillin, dicloxacillin and erythromycin) in cow's milk by high-performance thin-layer chromatography (HPTLC) combined with bioautography was developed. The test microorganism used for bioautography was Bacillus subtilis ATCC 6633. Antibiotic residues were extracted with acetonitrile, fat eliminated with petroleum ether and residues isolated with dichloromethane The sensitivity of the method guarantees the detection of the above-mentioned antibiotics at levels below maximum residue limits (MRL) allowed for milk. Percentage recoveries ranged between 90 and 100%, with coefficients of variation between 7.2 and 21.3%. Some advantages of this methodology over thin-layer chromatography (TLC)/bioautography are also discussed.     

The Orphan Seven-Transmembrane Receptor Apj Supports the Entry of Primary T-Cell-Line-Tropic and Dualtropic Human Immunodeficiency Virus Type 1

Human immunodeficiency virus type 1 (HIV-1) enters target cells by sequential binding to CD4 and specific seven-transmembrane-segment (7TMS) coreceptors. Viruses use the chemokine receptor CCR5 as a coreceptor in the early, asymptomatic stages of HIV-1 infection but can adapt to the use of other receptors such as CXCR4 and CCR3 as the infection proceeds. Here we identify one such coreceptor, Apj, which supported the efficient entry of several primary T-cell-line tropic (T-tropic) and dualtropic HIV-1 isolates and the simian immunodeficiency virus SIVmac316. Another 7TMS protein, CCR9, supported the less efficient entry of one primary T-tropic isolate. mRNAs for both receptors were present in phytohemagglutinin- and interleukin-2-activated peripheral blood mononuclear cells. Apj and CCR9 share with other coreceptors for HIV-1 and SIV an N-terminal region rich in aromatic and acidic residues. These results highlight properties common to 7TMS proteins that can function as HIV-1 coreceptors, and they may contribute to an understanding of viral evolution in infected individuals.