Antibiotic susceptibility and molecular diversity of Bacillus anthracis strains in Chad: detection of a new phylogenetic subgroup

We genotyped 15 Bacillus anthracis isolates from Chad, Africa, using multiple-locus variable-number tandem repeat analysis and three additional direct-repeat markers. We identified two unique genotypes that represent a novel genetic lineage in the A cluster. Chadian isolates were susceptible to 11 antibiotics and free of 94 antibiotic resistance genes.

Functional, structural and molecular plasticity of mammalian skeletal muscle in response to exercise stimuli

Biological systems have acquired effective adaptive strategies to cope with physiological challenges and to maximize biochemical processes under imposed constraints. Striated muscle tissue demonstrates a remarkable malleability and can adjust its metabolic and contractile makeup in response to alterations in functional demands. Activity-dependent muscle plasticity therefore represents a unique model to investigate the regulatory machinery underlying phenotypic adaptations in a fully differentiated tissue. Adjustments in form and function of mammalian muscle have so far been characterized at a descriptive level, and several major themes have evolved. These imply that mechanical, metabolic and neuronal perturbations in recruited muscle groups relay to the specific processes being activated by the complex physiological stimulus of exercise. The important relationship between the phenotypic stimuli and consequent muscular modifications is reflected by coordinated differences at the transcript level that match structural and functional adjustments in the new training steady state. Permanent alterations of gene expression thus represent a major strategy for the integration of phenotypic stimuli into remodeling of muscle makeup. A unifying theory on the molecular mechanism that connects the single exercise stimulus to the multi-faceted adjustments made after the repeated impact of the muscular stress remains elusive. Recently, master switches have been recognized that sense and transduce the individual physical and chemical perturbations induced by physiological challenges via signaling cascades to downstream gene expression events. Molecular observations on signaling systems also extend the long-known evidence for desensitization of the muscle response to endurance exercise after the repeated impact of the stimulus that occurs with training. Integrative approaches involving the manipulation of single factors and the systematic monitoring of downstream effects at multiple levels would appear to be the ultimate method for pinpointing the mechanism of muscle remodeling. The identification of the basic relationships underlying the malleability of muscle tissue is likely to be of relevance for our understanding of compensatory processes in other tissues, species and organisms.

The use of light- and electron microscopy for studies on the cell- and molecular biology of parasites and parasitic diseases

Lightmicroscopical (LM) and electron microscopi cal (EM) techniques, have had a major influence on the development and direction of cell biology, and particularly also on the investigation of complex host-parasite relationships. Earlier, microscopy has been rather descriptive, but new technical and scientific advances have changed the situation. Microscopy has now become analytical, quantitative and three-dimensional, with greater emphasis on analysis of live cells with fluorescent markers. The new or improved techniques that have become available include immunocytochemistry using immunogold labeling techniques or fluorescent probes, cryopreservation and cryosectioning, in situ hybridization, fluorescent reporters for subcellular localization, micro-analytical methods for elemental distribution, confocal laser scanning microscopy, scanning tunneling microscopy and live-imaging. Taken together, these tools are providing both researchers and students with a novel and multidimensional view of the intricate biological processes during parasite development in the host.

Characterisation of six novel A-subunit mutations leading to congenital factor XIII deficiency and molecular analysis of the first diagnosed patient with this rare bleeding disorder

In 1960, the first case report on factor XIII deficiency was published describing a seven-year-old Swiss boy with a so far unknown bleeding disorder. Today, more than 60 mutations in the factor XIIIA- and B-subunit genes are known leading to congenital factor XIII deficiency. In the present study, we describe six novel mutations in the factor XIII A-subunit gene. Additionally, we present the molecular characterisation of the first described patient with congenital factor XIII deficiency. The six novel mutations include a small deletion, Glu202 delG, leading to a premature stop codon and truncation of the protein, and a splice site mutation at the exon 10/intron 10 boundary, +1G/A, giving rise to an incorrect spliced mRNA lacking exons 10 and 11. The remaining four mutations are characterised by the single amino acid changes Met159Arg, Gly215Arg, Trp375Cys, and His716Arg, and were expressed in COS-1 cells. Antigen levels and activity of the mutants were significantly reduced compared to the wild-type. The patient described in 1960 also shows a single amino acid change, Arg77Cys. Structural analysis of all mutant enzymes suggests several mechanisms leading to destabilisation of the protein.

Becker muscular dystrophy with marked divergence between clinical and molecular genetic findings: case series

Both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations of the X-linked dystrophin gene. BMD patients are less affected clinically than DMD patients. We present five patients with a diagnosis of BMD. First, two identical twins, with a deletion of exon 48 of the dystrophin gene, who experienced prominent muscle cramps from the age of three. The histopathological examination of muscle biopsies of these two twins revealed only very slight muscle fiber alterations. Second, two brothers who displayed marked, unusual intrafamilial variability of the clinical picture as well as showing a new point mutation in the dystrophin gene. And finally, a fifth boy who displayed a new point mutation in the dystrophin gene. Although he was clinically asymptomatic at the age of 15 and muscle biopsy only showed very minor myopathic signs, serum Creatine Kinase (CK) levels had been considerably elevated for years. Taken together, these cases add to the spectrum of marked discrepancies in clinical, histopathological and molecular genetic findings in BMD.

Neuropathological and molecular comparison between clinical and asymptomatic bovine spongiform encephalopathy cases

Interest in the proper neuropathological and molecular characterization of bovine spongiform encephalopathy (BSE) has increased since asymptomatic and atypical cases were detected in the cattle population by active disease surveillance. In this respect we investigated a total of 95 confirmed BSE cases originating from different active and passive surveillance categories (clinical suspects, emergency-slaughter, fallen stock and routinely slaughter) in Switzerland for their neuropathological and molecular phenotype. We looked for measurable differences between these categories in lesion profile, severity of spongiform change, degree of astrocytosis as well as immunohistochemical and molecular patterns of the disease-associated isoform of the prion protein (PrPd) in the caudal brainstem. Our results indicate significantly higher intensities of spongiform change in clinically affected compared to asymptomatic BSE cases. Similar effects were in trend observed for the intensities of PrPd deposition and astrocytosis, whereas the frequencies of morphological PrPd types and the molecular patterns in Western immunoblot were not different. Importantly, none of the animals included in this study revealed features of atypical BSE. Taken together, this study suggests that both clinically affected as well as asymptomatic Swiss BSE cases in cattle share the neuropathological and molecular phenotype of classical BSE and that asymptomatic classical BSE cases are at a pre-clinical stage of the disease rather than representing a true sub-clinical form of BSE.

Biological mediators and periodontal regeneration: a review of enamel matrix proteins at the cellular and molecular levels

BACKGROUND: Despite a large body of clinical and histological data demonstrating beneficial effects of enamel matrix proteins (EMPs) for regenerative periodontal therapy, it is less clear how the available biological data can explain the mechanisms underlying the supportive effects of EMPs. OBJECTIVE: To analyse all available biological data of EMPs at the cellular and molecular levels that are relevant in the context of periodontal wound healing and tissue formation. METHODS: A stringent systematic approach was applied using the key words "enamel matrix proteins" OR "enamel matrix derivative" OR "emdogain" OR "amelogenin". The literature search was performed separately for epithelial cells, gingival fibroblasts, periodontal ligament cells, cementoblasts, osteogenic/chondrogenic/bone marrow cells, wound healing, and bacteria. RESULTS: A total of 103 papers met the inclusion criteria. EMPs affect many different cell types. Overall, the available data show that EMPs have effects on: (1) cell attachment, spreading, and chemotaxis; (2) cell proliferation and survival; (3) expression of transcription factors; (4) expression of growth factors, cytokines, extracellular matrix constituents, and other macromolecules; and (5) expression of molecules involved in the regulation of bone remodelling. CONCLUSION: All together, the data analysis provides strong evidence for EMPs to support wound healing and new periodontal tissue formation.

Solitary small- to medium-sized pleomorphic T-cell nodules of undetermined significance: clinical, histopathological, immunohistochemical and molecular analysis of 26 cases

BACKGROUND: Solitary skin nodules composed of pleomorphic T lymphocytes are often the source of diagnostic problems. OBJECTIVE: To characterize the clinicopathological features, prognosis and optimal treatment modalities of patients with solitary lymphoid nodules of small- to medium-sized pleomorphic T lymphocytes. METHODS: Twenty-six patients were analysed for clinical, histopathological, immunophenotypical, molecular and follow-up data. Results: Lesions were located mainly on the head and neck (n = 16; 61.5%) or trunk (n = 8; 30.8%). Histopathology showed non-epidermotropic nodular or diffuse infiltrates of small- to medium-sized pleomorphic T lymphocytes. Monoclonality was found by PCR in 54.2% of cases (n = 13/24). After a mean follow-up of 79.7 months, a local recurrence could be observed only in 1 patient. CONCLUSIONS: Our patients have a specific cutaneous lymphoproliferative disorder characterized by reproducible clinicopathological features. The incongruity between the indolent clinical course and the worrying histopathological features poses difficulties in classifying these cases unambiguously as benign or malignant. We suggest to describe these lesions as 'solitary small- to medium-sized pleomorphic T-cell nodules of undetermined significance'. Irrespective of the name given to these equivocal cutaneous lymphoid proliferations, follow-up data support a non-aggressive therapeutic strategy.

Haematologic data, iron parameters and molecular findings in two new cases of iron-refractory iron deficiency anaemia

Matriptase-2 (Tmprss6), a type II transmembrane serine protease, has an essential role in iron homoeostasis as a hepcidin regulator. Recently, patients with TMPRSS6 mutations and suffering from iron-refractory iron deficiency anaemia (IRIDA) have been reported. We describe two new cases of IRIDA, one patient of Swiss origin and the second of Italian origin. The first case results from a large deletion of 1054 nucleotides corresponding to an in frame deletion of 30 amino acid residues in the low-density lipoprotein receptor-1/-2 (LDLR-1/-2) domains and from a missense mutation in CUB1 (S304L). In the second case, a homozygous G-->C mutation in the last nucleotide of exon 15 and which modified the consensus sequence of the 5' splice donor site of intron 15 (AGgt-->ACgt) was identified. Both patients had a high hepcidin level and low serum iron and transferrin saturation compared to age-matched controls. Continuous perfusion of i.v. iron 4 h/d x 5 d in the first case resulted in a significant rise in haemoglobin. These new cases of IRIDA illustrate the importance of LDLR-1/-2 and CUB1 domains in matriptase-2 function as well as the role of matriptase-2 in hepcidin regulation. Furthermore a deletional form of TMPRSS6 (in LDLR-1/-2 domains) resulting in IRIDA is described for the first time. These cases reinforce the belief that patients suffering from IRIDA have no specific geographical or ethnic distribution and are sporadic secondary to different mutations of the matriptase-2 gene.

Isolation and molecular characterization of recombinant Echinococcus granulosus P29 protein (recP29) and its assessment for the post-surgical serological follow-up of human cystic echinococcosis in young patients

We synthesized recombinant Echinococcus granulosus protoscolex recP29 antigen to be preliminarily assessed by ELISA and immunoblotting. RecP29-serology was carried out on 54 young patients with cystic echinococcosis (CE). Patients were classified into either cured (CCE) (n=40) or non-cured (NCCE) (n=14) CE patients. RecP29 ELISA showed a gradual decrease of antibody concentrations in all CCE cases that were initially (before treatment) seropositive to this antigen (25 out of 40) or that seroconverted following treatment. A complete seronegativity was reached within 3 years post-surgery in all of these cases. Conventional HCF ELISA yielded seronegativity in only 10% of initially recP29-seropositive CCE patients (P=0.086). Likewise, recP29 immunoblotting yielded seronegativity in 93% of 29 out of 40 initially recP29-immunoblot-positive CCE patients after 3 years follow-up, compared with 72% in the HCF immunoblotting (P=0.060). Eleven out of 14 NCCE patients were initially positive by recP29 ELISA, and 10 out of these maintained a marked anti-recP29 antibody reactivity until the endpoint of the follow-up period. All 14 NCCE cases were initially seropositive by recP29 immunoblotting, and 13 cases remained seropositive until the end of the study. Thus, recombinant P29 protein appears prognostically useful for monitoring those post-surgical CE cases with an initial seropositivity to this marker.

Phylogenetic analysis of Pasteurella multocida subspecies and molecular identification of feline P. multocida subsp. septica by 16S rRNA gene sequencing

Pasteurella multocida is commonly found in the oral cavity of cats and dogs. In humans it is known as an opportunistic pathogen after bites from these animals. Phenotypic identification of P. multocida based on biochemical reactions is often limited and usually only done on a species level, even though 3 subspecies are described. For molecular taxonomy and diagnostic purposes a phylogenetic analysis of the three subspecies of P. multocida based on their 16S rRNA (rrs) gene sequence was therefore carried out. We found P. multocida subsp. septica on a distinguished branch on the phylogenetic tree of Pasteurellaceae, due to a 1.5% divergence of its rrs gene compared to the two other, more closely related subspecies multocida and gallicida. This phylogenetic divergence can be used for the identification of P. multocida subsp. septica by rrs gene determination since they form a phylogenetically well isolated and defined group as shown with a set of feline isolates. Comparison to routine phenotypic identification shows the advantage of the sequence-based identification over conventional methods. It is therefore helpful for future unambiguous identification and molecular taxonomy of P. multocida as well as for epidemiological investigations.