RESUMEN

Clostridioides difficile is the leading cause of healthcare associated infections. The Pathogenicity Locus (PaLoc) toxins TcdA and TcdB promote host disease. These toxins lack canonical N-terminal signal sequences for translocation across the bacterial membrane, suggesting alternate mechanisms of release, which have included targeted secretion and passive release from cell lysis. While the holin TcdE has been implicated in TcdA and TcdB release, its role in vivo remains unknown. Here, we show profound reductions in toxin secretion in ΔtcdE mutants in the highly virulent strains UK1 (epidemic ribotype 027, Clade 3) and VPI10463 (ribotype 087, Clade 1). Notably, tcdE deletion in either strain rescued highly susceptible gnotobiotic mice from lethal infection by reducing acute extracellular toxin to undetectable levels, limiting mucosal damage, and enabling long-term survival, in spite of continued toxin gene expression in ΔtcdE mutants. Our findings confirm TcdE's critical functions in vivo for toxin secretion and C. difficile virulence.

RESUMEN

We describe the design, fabrication, and successful demonstration of a sample preparation module comprising bacteria cell capture and thermal lysis on-chip with potential applications in food sample pathogen analysis. Plasma nanotexturing of the polymeric substrate allows increase of the surface area of the chip and the antibody binding capacity. Three different anti-Salmonella antibodies were directly and covalently linked to plasma treated chips without any additional linker chemistry or other treatment. Then, the Ab-modified chips were tested for their capacity to bind bacteria in the concentration range of 10(2)-10(8) cells per mL; the module exhibited 100% efficiency in Salmonella enterica serovar Typhimurium bacteria capture for cell suspensions below 10(5) cells per mL (10(4) cells injected with a 100 µL sample volume) and efficiency higher than 50% for 10(7) cells per mL. Moreover, thermal lysis achieved on-chip from as low as 10 captured cells was demonstrated and shown to compare well with off-chip lysis. Excellent selectivity (over 1 : 300) was obtained in a sample containing, in addition to S. Typhimurium and E. coli bacteria.

Asunto(s)

Bacteriólisis , Escherichia coli/aislamiento & purificación , Dispositivos Laboratorio en un Chip , Nanoestructuras/química , Polímeros/química , Salmonella typhimurium/aislamiento & purificación , Escherichia coli/citología , Salmonella typhimurium/citología

RESUMEN

Clostridium difficile is an emergent human pathogen and the most common cause of nosocomial diarrhea. Our recent data strongly suggest the importance of RNA-based mechanisms for the control of gene expression in C. difficile. In an effort to understand the function of the RNA chaperone protein Hfq, we constructed and characterized an Hfq-depleted strain in C. difficile. Hfq depletion led to a growth defect, morphological changes, an increased sensitivity to stresses, and a better ability to sporulate and to form biofilms. The transcriptome analysis revealed pleiotropic effects of Hfq depletion on gene expression in C. difficile, including genes encoding proteins involved in sporulation, stress response, metabolic pathways, cell wall-associated proteins, transporters, and transcriptional regulators and genes of unknown function. Remarkably, a great number of genes of the regulon dependent on sporulation-specific sigma factor, SigK, were upregulated in the Hfq-depleted strain. The altered accumulation of several sRNAs and interaction of Hfq with selected sRNAs suggest potential involvement of Hfq in these regulatory RNA functions. Altogether, these results suggest the pleiotropic role of Hfq protein in C. difficile physiology, including processes important for the C. difficile infection cycle, and expand our knowledge of Hfq-dependent regulation in Gram-positive bacteria.

Asunto(s)

Clostridioides difficile/metabolismo , Pleiotropía Genética , Chaperonas Moleculares/metabolismo , Proteínas de Unión al ARN/metabolismo , Clostridioides difficile/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Técnicas de Silenciamiento del Gen , Humanos , Chaperonas Moleculares/genética , Mutación , ARN sin Sentido , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , Proteínas de Unión al ARN/genética , Transducción de Señal/fisiología , Esporas Bacterianas , Estrés Fisiológico

Asunto(s)

Autoanticuerpos/inmunología , Autoantígenos/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/diagnóstico , Enfermedades de los Párpados/inmunología , Gangliósidos/inmunología , Inmunoglobulina G/inmunología , Oftalmoplejía/inmunología , Neuritis Óptica/inmunología , Trastornos de la Visión/inmunología , Anciano de 80 o más Años , Autoanticuerpos/sangre , Enfermedades Autoinmunes del Sistema Nervioso/complicaciones , Enfermedades de los Párpados/fisiopatología , Femenino , Humanos , Inmunoglobulina G/sangre , Imagen por Resonancia Magnética , Mesencéfalo/fisiopatología , Neuritis Óptica/fisiopatología , Remisión Espontánea , Síndrome , Agudeza Visual

RESUMEN

The gold standards for the diagnosis of Clostridium difficile infections (CDIs) are the cytotoxicity assay and the toxigenic culture. However, both methods are time-consuming and the results are not available before 24-48 h. We developed and evaluated a multiplex in-house real-time polymerase chain reaction (PCR) assay for the simultaneous detection of toxigenic strains of C. difficile and the presumptive identification of the epidemic NAP1/027/BI strain from stools. Amplifications were performed using specific primers for tcdB and tcdC on an ABI Prism 7300 (Applied Biosystems). The detection of amplicons was done using TaqMan probes. The analytical sensitivity of the multiplex real-time PCR for detecting tcdB was estimated to 10 CFU/g of stools. This assay was assessed from 881 consecutive unformed stools from patients suspected of having CDI. The gold standard was the toxigenic culture for the diagnosis of CDI and PCR ribotyping for the identification of the NAP1/027/BI strain. The prevalence of positive toxigenic culture was 9.31%. Compared to the toxigenic culture, the sensitivity, specificity, and positive and negative predictive values were 86.59%, 97.43%, 78.02%, and 98.57%, respectively, for the real-time PCR and 70.73%, 100%, 100%, and 97.08%, respectively, for the cytotoxicity assay.

Asunto(s)

Técnicas Bacteriológicas/métodos , Clostridioides difficile/aislamiento & purificación , Infecciones por Clostridium/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa Multiplex/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Clostridioides difficile/genética , Infecciones por Clostridium/microbiología , Cartilla de ADN/genética , Heces/microbiología , Humanos , Sondas de Oligonucleótidos/química , Sondas de Oligonucleótidos/genética , Proteínas Represoras/genética , Sensibilidad y Especificidad

RESUMEN

Available evidence suggests a Polynesian origin of the Easter Island population. We recently found that some native Easter Islanders also carried some common American Indian (Amerindian) human leukocyte antigen (HLA) alleles, which probably were introduced before Europeans discovered the island in 1722. In this study, we report molecular genetic investigations of 21 other selected native Easter Islanders. Analysis of mitochondrial DNA and Y chromosome markers showed no traces of an Amerindian contribution. However, high-resolution genomic HLA typing showed that two individuals carried some other common Amerindian HLA alleles, different from those found in our previous investigations. The new data support our previous evidence of an Amerindian contribution to the gene pool on Easter Island.

Asunto(s)

Pool de Genes , Antígenos HLA/genética , Indígenas Sudamericanos/genética , Adulto , Anciano , Anciano de 80 o más Años , Frecuencia de los Genes , Genética de Población , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Antígenos HLA-DQ/genética , Cadenas alfa de HLA-DQ , Antígenos HLA-DR/genética , Cadenas HLA-DRB1 , Haplotipos/genética , Humanos , Persona de Mediana Edad , Polinesia

RESUMEN

Clostridium difficile toxin synthesis is growth phase-dependent and is regulated by various environmental signals. The toxin genes tcdA and tcdB are located in a pathogenicity locus, which also includes three accessory genes, tcdR, tcdC and tcdE. TcdR has been shown to act as an alternative sigma factor that mediates positive regulation of both the toxin genes and its own gene. The tcdA, tcdB and tcdR genes are transcribed during the stationary growth phase. The tcdC gene, however, is expressed during exponential phase. This expression pattern suggested that TcdC may act as a negative regulator of toxin gene expression. TcdC is a small acidic protein without any conserved DNA-binding motif. It is able to form dimers and its N-terminal region includes a putative transmembrane domain. Genetic and biochemical evidence showed that TcdC negatively regulates C. difficile toxin synthesis by interfering with the ability of TcdR-containing RNA polymerase to recognize the tcdA and tcdB promoters. In addition, the C. difficile NAP1/027 epidemic strains that produce higher levels of toxins have mutations in tcdC. Interestingly, a frameshift mutation at position 117 of the tcdC coding sequence seems to be, at least in part, responsible for the hypertoxigenicity phenotype of these epidemic strains.

Asunto(s)

Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/fisiología , Toxinas Bacterianas/biosíntesis , Clostridioides difficile/patogenicidad , Enterotoxinas/biosíntesis , Proteínas Represoras/fisiología , Proteínas Bacterianas/genética , Clostridioides difficile/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Humanos , Proteínas Represoras/genética

RESUMEN

Most archaeological and linguistic evidence suggest a Polynesian origin of the population of Easter Island (Rapanui), and this view has been supported by the identification of Polynesian mitochondrial DNA (mtDNA) polymorphisms in prehistoric skeletal remains. However, some evidence of an early South American contact also exists (the sweet potato, bottle gourd etc.), but genetic studies have so far failed to show an early Amerindian contribution to the gene pool on Easter Island. To address this issue, we analyzed mtDNA and Y chromosome markers and performed high-resolution human leukocyte antigen (HLA) genotyping of DNA harvested from previously collected sera of 48 reputedly nonadmixed native Easter Islanders. All individuals carried mtDNA types and HLA alleles previously found in Polynesia, and most men carried Y chromosome markers of Polynesian origin, providing further evidence of a Polynesian origin of the population of Easter Island. A few individuals carried HLA alleles and/or Y chromosome markers of European origin. More interestingly, some individuals carried the HLA alleles A*0212 and B*3905, which are of typical Amerindian origin. The genealogy of some of the individuals carrying these non-Polynesian HLA alleles and their haplotypic backgrounds suggest an introduction into Easter Island in the early 1800s, or earlier. Thus, there may have been an early European and Amerindian contribution to the Polynesian gene pool of Easter Island.

Asunto(s)

Indio Americano o Nativo de Alaska , Genética de Población , Población Blanca , Antígenos HLA/genética , Humanos , Linaje , Polinesia/etnología

RESUMEN

We present a theory to explain the emergence of a particle-rich ridge observed experimentally in a thin film particle-laden flow on an incline. We derive a lubrication theory for this system which is qualitatively compared to preliminary experimental data. The ridge formation arises from the creation of two shocks due to the differential transport rates of fluid and particles. This parallels recent findings of double shocks in thermal-gravity-driven flow [A. L. Bertozzi, Phys. Rev. Lett. 81, 5169 (1998); J. Sur, Phys. Rev. Lett. 90, 126105 (2003); A. Munch, Phys. Rev. Lett. 91, 016105 (2003)]. However, here the emergence of the shocks arises from a new mechanism involving the settling rates of the species.

Asunto(s)

Modelos Teóricos , Tamaño de la Partícula , Preparaciones Farmacéuticas/química

RESUMEN

Precise estimates of mutation rates at Y-chromosomal microsatellite STR (short tandem repeat) loci make an important basis for paternity diagnostics and dating of Y chromosome lineage origins. There are indications of considerable locus mutation rate variability between (inter-) and within (intra-) loci. We have studied nine Y-STR loci-DYS19, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS385, and DYS388-in 1,766 father-son pairs of confirmed paternity (a total of 15,894 meioses). Five biallelic markers were also analyzed in the fathers-Tat, YAP, 12f2, SRY1532, and 92R7-defining haplogroups 1, 2, 3, 4, 9, and 16, respectively. A total of 36 fragment length mutations were observed: 24 gains (22 single-step, two double-step) and 12 single-step losses. Thus, there was a significant surplus of gains (p=0.045). Overall, the mutation rate was positively correlated to STR repeat length and there was a significant relative excess of losses in long alleles and gains in short alleles (p=0.043). In contrast to the situation in autosomal STR loci and in MSY-1, no noteworthy correlation between mutation rate and the father's age at the child's birth was observed. We observed significant interlocus differences in Y-STR mutation rates (p<0.01). The number of observed mutations ranged from zero in DYS392 to eight in DYS391 and DYS390. We have also demonstrated obvious differences in mutation rates between the haplogroups studied (p=0.024), a phenomenon that is a reflection of the dependence of mutation rate on allele size. Our study has thus demonstrated the necessity of not only locus-specific, but even allele-specific, mutation rate estimates for forensic and population genetic purposes, and provides a considerable basis for such estimates.

Asunto(s)

Cromosomas Humanos Y/genética , Marcadores Genéticos/genética , Repeticiones de Minisatélite/genética , Mutación/genética , Adolescente , Adulto , Factores de Edad , Padre , Humanos , Masculino , Meiosis/genética , Persona de Mediana Edad , Mutagénesis/genética , Núcleo Familiar

RESUMEN

Future surgical strategies to restore neurological function in peripheral nerve loss may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. Random copolymers of trimethylene carbonate and epsilon caprolactone (P(epsilonCL-TMC), 50: 50) have been synthesized by ring opening polymerization using rare earth alkoxides as initiator. Their potential use as nerve guide repairs has been assessed through indirect and direct in vitro biocompatibility tests and in vivo soft tissue response to EDI subclass macrophages. In vitro, we exposed monolayers of human skin fibroblasts and an established continuous cell line (Hela) to liquid extracts (either pure or diluted in the culture medium) of epsilonCL-TMC copolymer including positive (phenol) and negative controls. Then, colorimetric assays (Neutral red and MTT) were performed. The extracts of epsilonCL-TMC induced no significant cytotoxic effect. We also exposed in vitro Schwann cells to pieces of P(epsilonCL-TMC) and P(LA-GA) copolymers. We evaluated cell attachment at 1 and 3 h by measuring the activity of the lysosomal enzyme (N-acetyl-beta-hexosaminidase) and cell proliferation at 1, 3, 6 and 9 days by measuring the cell metabolic activity (MTT assay). Values for attachment slightly decreased between 1 and 3 h but were significantly higher than on agars (negative control). Cells plated on epsilonCL-TMC showed a rate of proliferation comparable with that of normalized controls and higher than on PGA-PLA at day 9. Finally, we evaluated in vivo the soft tissue response after implantation of cylindrical tubes of P(epsilonCL-TMC) and P(LA-GA) copolymers with an immunohistochemistry staining procedure for the newly recruited ED1 macrophages. An image analysis system automatically measured the optical density of labelled positive ED1 cells at 9, 21 and 60 days after implantation. epsilonCL-TMC copolymer showed a mild soft tissue reaction with no adverse chronic inflammatory reaction. These data allowed us to consider this conduit as a potential effective substitute in nerve repair. El sevier Science Ltd. All rights reserved.

Asunto(s)

Materiales Biocompatibles , Lactonas , Traumatismos de los Nervios Periféricos , Nervios Periféricos/cirugía , Polímeros , Animales , Adhesión Celular , División Celular , Células Cultivadas , Células HeLa , Humanos , Ácido Láctico , Macrófagos/citología , Masculino , Ensayo de Materiales , Regeneración Nerviosa , Poliésteres , Ácido Poliglicólico , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas , Ratas Endogámicas F344 , Células de Schwann/citología , Células de Schwann/trasplante , Ingeniería de Tejidos/métodos

RESUMEN

A collaborative exercise was carried out by the European DNA Profiling Group (EDNAP) in the frame work of the STADNAP program, i.e. standardization of DNA profiling in Europe, in order to evaluate the performance of a Y-chromosome STR pentaplex, which includes the loci DYS19, DYS389 I and II, DYS390 and DYS393 and to determine whether uniformity of results could be achieved among different European laboratories. Laboratories were asked to analyze the five Y-STRs using singleplex and multiplex conditions in three bloodstains and one mixed stain (95% female and 5% male). All the laboratories reported the same results even for the mixed stain included in the exercise. This demonstrates the reproducibility and robustness of Y-chromosome STR typing even with multiplex formats and proves the usefulness of Y-STR systems for analyzing mixed stains with a male component.A total of 930 male samples from 10 different populations from Europe were also analysed for all the loci included in the pentaplex. Eight of these ten populations also included haplotype data. As for single gene analysis, haplotype diversity was higher in Germany and Italy and lower in Western European countries and Finland. Pairwise haplotype analysis shows the Finnish departure from the rest of the populations and a relatively homogeneity in the other European populations with F(ST) estimates lower than 0.05.UPGMA analysis shows an association of Western European population (Ireland, UK, Portugal and Galicia) on the one hand and central European populations on the other.

Asunto(s)

Dermatoglifia del ADN/métodos , Frecuencia de los Genes/genética , Variación Genética/genética , Repeticiones de Minisatélite/genética , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo Genético/genética , Cromosoma Y/genética , Manchas de Sangre , Conducta Cooperativa , Dermatoglifia del ADN/normas , Europa (Continente) , Femenino , Haplotipos , Humanos , Relaciones Interinstitucionales , Laboratorios , Masculino , Reacción en Cadena de la Polimerasa/normas , Estándares de Referencia

RESUMEN

Clostridium difficile, a causative agent of antibiotic-associated diarrhea and its potentially lethal form, pseudomembranous colitis, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The level of toxin production appears to be critical for determining the severity of the disease, but the mechanism by which toxin synthesis is regulated is unknown. The product of a gene, txeR, that lies just upstream of the tox gene cluster was shown to be needed for tox gene expression in vivo and to activate promoter-specific transcription of the tox genes in vitro in conjunction with RNA polymerases from C. difficile, Bacillus subtilis, or Escherichia coli. TxeR was shown to function as an alternative sigma factor for RNA polymerase. Because homologs of TxeR regulate synthesis of toxins and a bacteriocin in other Clostridium species, TxeR appears to be a prototype for a novel mode of regulation of toxin genes.

Asunto(s)

Toxinas Bacterianas/biosíntesis , Clostridioides difficile/metabolismo , Factor sigma/fisiología , Toxinas Bacterianas/genética , Clostridioides difficile/genética , ARN Polimerasas Dirigidas por ADN/metabolismo , Escherichia coli/enzimología , Regulación Bacteriana de la Expresión Génica/fisiología , Regiones Promotoras Genéticas , Unión Proteica

RESUMEN

The reference database of highly informative Y-chromosomal short tandem repeat (STR) haplotypes (YHRD), available online at http://ystr.charite.de, represents the largest collection of male-specific genetic profiles currently available for European populations. By September 2000, YHRD contained 4688 9-locus (so-called "minimal") haplotypes, 40% of which have been extended further to include two additional loci. Establishment of YHRD has been facilitated by the joint efforts of 31 forensic and anthropological institutions. All contributing laboratories have agreed to standardize their Y-STR haplotyping protocols and to participate in a quality assurance exercise prior to the inclusion of any data. In view of its collaborative character, and in order to put YHRD to its intended use, viz. the support of forensic caseworkers in their routine decision-making process, the database has been made publicly available via the Internet in February 2000. Online searches for complete or partial Y-STR haplotypes from evidentiary or non-probative material can be performed on a non-commercial basis, and yield observed haplotype counts as well as extrapolated population frequency estimates. In addition, the YHRD website provides information about the quality control test, genotyping protocols, haplotype formats and informativity, population genetic analysis, literature references, and a list of contact addresses of the contributing laboratories.

Asunto(s)

Bases de Datos Factuales , Haplotipos , Secuencias Repetidas en Tándem/genética , Cromosoma Y/genética , Europa (Continente) , Genética de Población , Humanos , Masculino

RESUMEN

Y-chromosome DNA profiles are promising tools in population genetics and forensic science. Here we present DNA profiles of 300 unrelated Y-chromosomes of Norwegian origin. The profile is composed of eight short tandem repeats (STRs) and one single nucleotide polymorphism (SNP). In more than 2/3 of the haplotypes the modular structure in the 5' end of the minisatellite locus DYF155S1 was revealed by minisatellite variant repeat PCR (MVR-PCR) These haplotypes were also typed for deletions of fragment 50f2C (DYF155S2). Allele distribution and paternity exclusion parameters are given for each marker. The degree of haplotype diversity and its implication for statistics are evaluated. In the 300 samples 177 different haplotypes were encountered, of which 137 were observed once only. Analysis showed that the main source of variation is within the population. The Fst values were less than 0.015 in general. Haplotype grouping by the SNP demonstrated two haplogroups (Tat/T and Tat/C). Haplogroup Tat/C--found in 5.7% of the present material - is the same haplogroup as encountered in 60% of Finnish males [Am. J. Hum. Genet. 62 (1998) 1171]. Mutation analysis in 150 father/son pairs (a total of 1200 meiotic events) revealed an average mutation frequency of 0.0042 (95% CI 0.0014-0.0097).

Asunto(s)

ADN/genética , Genética de Población , Secuencias Repetidas en Tándem , Cromosoma Y/genética , Alelos , Variación Genética , Haploidia , Humanos , Masculino , Noruega , Reacción en Cadena de la Polimerasa , Terminología como Asunto

RESUMEN

The GATA repeat DYS393 was reported in 1987 among other Y-specific short tandem repeats. It has since been used for forensic and evolutionary studies. We decided to test its Y-specificity when we found that female DNA gave amplicons, in agreement with recent GDB-recorded experiences on radiation hybrids. Parent-child triplets revealed that heterozygous daughters always carried the same paternally derived amplicon which, however, was not amplified in their fathers' DNAs. The X-assignment was verified in larger families. A half-new primer set with a new reverse DYS393 primer, outside the old one, resulted in X amplicons in females as well as Y and X amplicons in males. This new primer set defines the new DXYS267 (GDB Data Curation). DNA-sequencing revealed four base pair differences between the Y- and the X-sequences. Two are within the reverse primer site sequence, thus probably causing preferential hybridization to the Y sequence when using the conventional primers. The two others are within the repeat array, giving the regular repeat GATA in the Y-sequence, and TATA and GACA, respectively, in the X-sequence. Allele frequency distribution in DYS393 was studied in 300 unrelated Norwegian males, allele distribution in the X-locus in 48 Norwegian women. Even if allele repeat numbers are overlapping between the loci, leading to identical fragment lengths, the allele distribution is different between DYS393 and the X-chromosome locus. The differences between the two homologous loci on the Y and X indicate a considerable lap of time since common ancestry. To avoid co-amplification of the X-locus in DYS393 typing, primer A was elongated to include one of the sequence differences between the two loci. This to a considerable extent improved the specificity of the DYS393 primers.

Asunto(s)

Cartilla de ADN , Secuencias Repetidas en Tándem/genética , Cromosoma X/genética , Cromosoma Y/genética , Adenina , Alelos , Emparejamiento Base/genética , Quimera/genética , Mapeo Cromosómico , Citosina , ADN/genética , Evolución Molecular , Femenino , Medicina Legal , Amplificación de Genes , Frecuencia de los Genes , Variación Genética , Guanina , Heterocigoto , Humanos , Masculino , Noruega , Polimorfismo Genético/genética , Análisis de Secuencia de ADN , Timina

RESUMEN

BACKGROUND: The role of nitrous oxide exposure in neurologic complications of subclinical cobalamin deficiency has been reported, but few cases are well documented. OBSERVATION: Two weeks after surgery for prosthetic adenoma, a 69-year-old man developed ascending paresthesia of the limbs, severe ataxia of gait, tactile sensory loss on the 4 limbs and trunk, and absent tendon reflexes. After a second surgical intervention, the patient became confused. Four months after onset, the patient had paraplegia, severe weakness of the upper limbs, cutaneous anesthesia sparing the head, and confusion. Moderate macrocytosis, low serum B12 levels, and a positive Schilling test result led to the diagnosis of pernicious anemia. Results of electrophysiologic examinations showed a diffuse demyelinating neuropathy. Magnetic resonance imaging of the spinal cord disclosed hyperintensities of the dorsal columns on T2-weighted images. CONCLUSIONS: Pernicious anemia can result in severe neurologic symptoms with only mild hematologic changes. The role of nitrous oxide anesthesia in revealing subclinical B12 deficiency must be emphazised. Magnetic resonance imaging of the spinal cord might be helpful in making the diagnosis.

Asunto(s)

Anemia Perniciosa/inducido químicamente , Anestésicos por Inhalación/efectos adversos , Enfermedades Desmielinizantes/inducido químicamente , Óxido Nitroso/efectos adversos , Adenoma/cirugía , Anciano , Anemia Perniciosa/complicaciones , Enfermedades Desmielinizantes/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Neoplasias de la Próstata/cirugía , Médula Espinal/patología , Deficiencia de Vitamina B 12/complicaciones , Deficiencia de Vitamina B 12/diagnóstico

RESUMEN

Y-chromosome linked short tandem repeat (STR) loci are inherited as a closely linked haplotype, which appears to remain stable in a given paternal lineage over many generations. In forensic cases, Y-linked STRs are particularly useful for the identification of human remains as well as in rape cases with mixed male/female stain samples. DYS385 is derived from tandemly duplicated segments of the Y chromosome thus giving rise to two fragments of variable length which do not behave like alleles but genotypes. The European DNA Profiling (EDNAP) group has carried out a collaborative exercise among 14 participating laboratories using DYS385 for typing of five unknown bloodstains and a control sample. Furthermore, population data from eight different European countries with samples sizes between 91 and 150 male individuals were collected. The results confirm previous observations that DYS385 is one of the most informative Y-linked STR loci. It could also be demonstrated that reproducible results can be obtained independently from the electrophoretic separation and detection methods used. Thus DYS385 may serve as a useful complementation to the routinely used autosomal STR systems in special cases.

Asunto(s)

Manchas de Sangre , Dermatoglifia del ADN/métodos , Dermatoglifia del ADN/normas , Ligamiento Genético/genética , Cooperación Internacional , Repeticiones de Minisatélite/genética , Cromosoma Y/genética , Electroforesis de las Proteínas Sanguíneas/métodos , Electroforesis de las Proteínas Sanguíneas/normas , Europa (Continente) , Genética de Población , Humanos , Masculino , Reproducibilidad de los Resultados

RESUMEN

Flow cytometry was used to quantify apoptotic and necrotic polymorphonuclear (PMN) cells in an exudate generated by biomaterials, and the results were compared with determinations of spontaneous apoptosis and necrosis in PMN cells from the bloodstream. The exudate formed inside cylindrical tubes subcutaneously implanted in the dorsal region of rats was collected over a 1-week period. A rapid and simple staining procedure based on the spectral properties of the bisbenzemide Hoechst 33342 was used to identify apoptotic PMN cells. Quantification of permeabilized PMN cells stained by propidium iodide was possible in the same unfixed specimens. The percentages of apoptotic and permeabilized PMN cells in peripheral rat blood were low (1.8 +/-0 0.5% and 1.7 +/- 0.7%, respectively), similar to results found in humans. In exudates generated by polyvinyl chloride (PVC), the percentages of apoptotic and permeabilized PMN cells were higher than in the blood. The percentage of PMN cells undergoing apoptosis progressively increased with time and reached a maximum at day 2 (27% +/- 6%). The percentage of permeabilized cells progressively increased with time and was much higher than the percentage of apoptotic cells on days 4 and 8. Apoptosis and necrosis of PMN cells at day 2 were inhibited when tubes were filled with 10% serum. Selective inhibition of apoptosis with a caspase inhibitor in vivo indicated that apoptosis and necrosis are two separate pathways leading to the death of PMN cells in the exudate. At day 2, polyurethane (PU) was associated with a lower rate of apoptosis than PVC or a random copolymer of trimethylene carbonate (TMC) and epsiloncaprolactone (ECL). Apoptosis was interpreted as an organized cell removal process that limits inflammation. Apoptosis was the natural route of PMN cell death at the early stage of inflammation.

Asunto(s)

Apoptosis , Materiales Biocompatibles/toxicidad , Exudados y Transudados/citología , Reacción a Cuerpo Extraño/patología , Lactonas/toxicidad , Neutrófilos/patología , Polímeros/toxicidad , Poliuretanos/toxicidad , Cloruro de Polivinilo/toxicidad , Implantación de Prótesis/efectos adversos , Animales , Apoptosis/efectos de los fármacos , Permeabilidad de la Membrana Celular , Células Cultivadas , Inhibidores de Cisteína Proteinasa/farmacología , Fibroblastos/efectos de los fármacos , Citometría de Flujo , Reacción a Cuerpo Extraño/etiología , Humanos , Masculino , Ensayo de Materiales , Muramidasa/análisis , Necrosis , Neutrófilos/efectos de los fármacos , Poliésteres , Prótesis e Implantes , Ratas , Ratas Wistar , Factores de Tiempo

RESUMEN

Indirect evidence from human and monkey investigations supports the idea that impaired frontal tasks in Parkinson's disease (PD) may result from striato-frontal disruption caused by dopamine (DA) denervation of the caudate nucleus. To directly investigate this hypothesis, we used PET with 11C-S-Nomifensine (11C-S-NMF), a sensitive marker of striatal DA denervation, in 10 non-demented PD patients in whom two frontal executive tests, the object alternation (OA) and the conditional associative learning (CAL) tasks, thought to reflect mainly set-shifting/inhibition and planning, respectively, were given. In addition, the central executive function of verbal working memory was assessed with the Brown Peterson paradigm (BPP). We found a highly significant correlation between right caudate 11C-S-NMF specific binding and OA performance, less significant and reverse-direction correlations between CAL performance and putamen 11C-S-NMF binding, and no significant correlation with BPP performance. Thus, caudate DA denervation may subtend poor set-shifting/inhibition process in PD. Our results also point to distinct and complex relationships between striatal DA and specific frontal tasks.

Asunto(s)

Cuerpo Estriado/fisiopatología , Lóbulo Frontal/efectos de los fármacos , Pruebas Neuropsicológicas , Enfermedad de Parkinson/fisiopatología , Simpatectomía Química/efectos adversos , Adulto , Anciano , Núcleo Caudado/fisiopatología , Dopamina/efectos adversos , Inhibidores de Captación de Dopamina/farmacología , Femenino , Lóbulo Frontal/fisiología , Humanos , Masculino , Persona de Mediana Edad , Nomifensina/análogos & derivados , Nomifensina/farmacología , Tomografía Computarizada de Emisión