Evaluation of VIDAS® Listeria species Xpress (LSX) Immunoassay Method for the Detection of Listeria species in Foods: Collaborative Study

In a multilaboratory study, the effectiveness of an alternative method for rapid screening of Listeria species compared to traditional reference methods was demonstrated in a variety of food products. A collaborative study was conducted to compare the VIDAS® Listeria species Xpress (LSX) method and the standard cultural methods for the detection of Listeria species in foods. Six food types were tested: vanilla ice cream, cheddar cheese, raw ground beef, frozen green beans, deli turkey, and cooked shrimp. Each food, inoculated with a different Listeria strain at two levels and uninoculated test portions, was analyzed by each method. A total of 15 laboratories representing government and industry participated. In this study 1134 tests were analyzed in the statistical analysis. There were 490 positives by the VIDAS LSX method using the sample boiling step, 483 positives by the VIDAS LSX method using the Heat and Go system, and 439 positives by the standard culture methods. Overall, the Chi-square result for the VIDAS LSX method with boiling for all foods was 7.25, indicating a significant statistical difference between the VIDAS method and the standard methods at the 5% confidence. For the VIDAS LSX method with the Heat and Go system, the Chi-square result for all foods was 5.37, indicating a significant statistical difference between the VIDAS LSX assay with the Heat and Go system and the standard methods at the 5% level of significance. In both cases, the VIDAS method was more sensitive than the standard methods. The LSX method detects Listeria species in foods with negative or presumptive positive results in a minimum of 30 h compared to at least 5 days for the cultural methods. Based on the results of this collaborative study, it is recommended that the VIDAS LSX method be adopted as an AOAC Official MethodSM for the detection of Listeria species in dairy products, vegetables, seafood, raw meats and poultry, and processed meats and poultry.

[Long-term effect of policosanol on the functional recovery of non-cardioembolic ischemic stroke patients: a one year study]

INTRODUCTION

Stroke is a leading cause of mortality and disability. Policosanol has been effective in brain ischemia models. The aim of this study is to investigate whether policosanol, added to aspirin therapy within 30 days of stroke onset, is better than placebo + aspirine for the long-term recovery of non-cardioembolic ischemic stroke subjects.

PATIENTS AND METHODS

Randomized, double-blind, placebo-controlled study. Eighty patients (mean age: 69 years) within 30 days of onset, with a modified Rankin Scale score (mRS) 2 to 4, were included. They were randomized in two groups (policosanol + aspirine or placebo + aspirine) for 12 months.

RESULTS

Policosanol + aspirine decreased significantly mean mRS from the first interim check-up (1.5 months). The treatment even improved after long-term therapy. More policosanol + aspirin (87.5%) than placebo + aspirine (0%) patients achieved mRSs <= 1. Policosanol + aspirine increased significantly Barthel Index, lowered LDL-cholesterol and increased HDL-cholesterol versus placebo + aspirin.

CONCLUSIONS

Long-term (12 months) administration of policosanol + aspirin given after suffering non-cardioembolic ischemic stroke was shown to be better than placebo + aspirin in improving functional outcomes when used among patients with non-cardioembolic ischemic stroke of moderate severity.

Genetic variation and RNA binding proteins: tools and techniques to detect functional polymorphisms

At its most fundamental level the goal of genetics is to connect genotype to phenotype. This question is asked at a basic level evaluating the role of genes and pathways in genetic model organism. Increasingly, this question is being asked in the clinic. Genomes of individuals and populations are being sequenced and compared. The challenge often comes at the stage of analysis. The variant positions are analyzed with the hope of understanding human disease. However after a genome or exome has been sequenced, the researcher is often deluged with hundreds of potentially relevant variations. Traditionally, amino-acid changing mutations were considered the tractable class of disease-causing mutations; however, mutations that disrupt noncoding elements are the subject of growing interest. These noncoding changes are a major avenue of disease (e.g., one in three hereditary disease alleles are predicted to affect splicing). Here, we review some current practices of medical genetics, the basic theory behind biochemical binding and functional assays, and then explore technical advances in how variations that alter RNA protein recognition events are detected and studied. These advances are advances in scale-high-throughput implementations of traditional biochemical assays that are feasible to perform in any molecular biology laboratory. This chapter utilizes a case study approach to illustrate some methods for analyzing polymorphisms. The first characterizes a functional intronic SNP that deletes a high affinity PTB site using traditional low-throughput biochemical and functional assays. From here we demonstrate the utility of high-throughput splicing and spliceosome assembly assays for screening large sets of SNPs and disease alleles for allelic differences in gene expression. Finally we perform three pilot drug screens with small molecules (G418, tetracycline, and valproic acid) that illustrate how compounds that rescue specific instances of differential pre-mRNA processing can be discovered.

Three rare diseases in one Sib pair: RAI1, PCK1, GRIN2B mutations associated with Smith-Magenis Syndrome, cytosolic PEPCK deficiency and NMDA receptor glutamate insensitivity

The National Institutes of Health Undiagnosed Diseases Program evaluates patients for whom no diagnosis has been discovered despite a comprehensive diagnostic workup. Failure to diagnose a condition may arise from the mutation of genes previously unassociated with disease. However, we hypothesized that this could also co-occur with multiple genetic disorders. Demonstrating a complex syndrome caused by multiple disorders, we report two siblings manifesting both similar and disparate signs and symptoms. They shared a history of episodes of hypoglycemia and lactic acidosis, but had differing exam findings and developmental courses. Clinical acumen and exome sequencing combined with biochemical and functional studies identified three genetic conditions. One sibling had Smith-Magenis Syndrome and a nonsense mutation in the RAI1 gene. The second sibling had a de novo mutation in GRIN2B, which resulted in markedly reduced glutamate potency of the encoded receptor. Both siblings had a protein-destabilizing homozygous mutation in PCK1, which encodes the cytosolic isoform of phosphoenolpyruvate carboxykinase (PEPCK-C). In summary, we present the first clinically-characterized mutation of PCK1 and demonstrate that complex medical disorders can represent the co-occurrence of multiple diseases.

Cornelia de Lange syndrome: further delineation of phenotype, cohesin biology and educational focus, 5th Biennial Scientific and Educational Symposium abstracts

Cornelia de Lange syndrome (CdLS) is the prototype for the cohesinopathy disorders that have mutations in genes associated with the cohesin subunit in all cells. Roberts syndrome is the next most common cohesinopathy. In addition to the developmental implications of cohesin biology, there is much translational and basic research, with progress towards potential treatment for these conditions. Clinically, there are many issues in CdLS faced by the individual, parents and caretakers, professionals, and schools. The following abstracts are presentations from the 5th Cornelia de Lange Syndrome Scientific and Educational Symposium on June 20-21, 2012, in conjunction with the Cornelia de Lange Syndrome Foundation National Meeting, Lincolnshire, IL. The research committee of the CdLS Foundation organizes the meeting, reviews and accepts abstracts and subsequently disseminates the information to the families. In addition to the basic science and clinical discussions, there were educationally-focused talks related to practical aspects of management at home and in school. AMA CME credits were provided by Greater Baltimore Medical Center, Baltimore, MD.

Glycosylation, hypogammaglobulinemia, and resistance to viral infections

Genetic defects in MOGS, the gene encoding mannosyl-oligosaccharide glucosidase (the first enzyme in the processing pathway of N-linked oligosaccharide), cause the rare congenital disorder of glycosylation type IIb (CDG-IIb), also known as MOGS-CDG. MOGS is expressed in the endoplasmic reticulum and is involved in the trimming of N-glycans. We evaluated two siblings with CDG-IIb who presented with multiple neurologic complications and a paradoxical immunologic phenotype characterized by severe hypogammaglobulinemia but limited clinical evidence of an infectious diathesis. A shortened immunoglobulin half-life was determined to be the mechanism underlying the hypogammaglobulinemia. Impaired viral replication and cellular entry may explain a decreased susceptibility to infections.

Genome-wide DNA methylation analysis in cohesin mutant human cell lines

The cohesin complex has recently been shown to be a key regulator of eukaryotic gene expression, although the mechanisms by which it exerts its effects are poorly understood. We have undertaken a genome-wide analysis of DNA methylation in cohesin-deficient cell lines from probands with Cornelia de Lange syndrome (CdLS). Heterozygous mutations in NIPBL, SMC1A and SMC3 genes account for ∼65% of individuals with CdLS. SMC1A and SMC3 are subunits of the cohesin complex that controls sister chromatid cohesion, whereas NIPBL facilitates cohesin loading and unloading. We have examined the methylation status of 27 578 CpG dinucleotides in 72 CdLS and control samples. We have documented the DNA methylation pattern in human lymphoblastoid cell lines (LCLs) as well as identified specific differential DNA methylation in CdLS. Subgroups of CdLS probands and controls can be classified using selected CpG loci. The X chromosome was also found to have a unique DNA methylation pattern in CdLS. Cohesin preferentially binds to hypo-methylated DNA in control LCLs, whereas the differential DNA methylation alters cohesin binding in CdLS. Our results suggest that in addition to DNA methylation multiple mechanisms may be involved in transcriptional regulation in human cells and in the resultant gene misexpression in CdLS.

Transcriptional dysregulation in NIPBL and cohesin mutant human cells

Genome-wide studies using cells from patients with Cornelia de Lange Syndrome reveal a role for cohesin in regulating gene expression in human cells.

Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL) facilitating its loading and unloading. In addition to this canonical role, cohesin has also been demonstrated to play a critical role in regulation of gene expression in nondividing cells. Heterozygous mutations in the cohesin regulator NIPBL or cohesin structural components SMC1A and SMC3 result in the multisystem developmental disorder Cornelia de Lange Syndrome (CdLS). Genome-wide assessment of transcription in 16 mutant cell lines from severely affected CdLS probands has identified a unique profile of dysregulated gene expression that was validated in an additional 101 samples and correlates with phenotypic severity. This profile could serve as a diagnostic and classification tool. Cohesin binding analysis demonstrates a preference for intergenic regions suggesting a cis-regulatory function mimicking that of a boundary/insulator interacting protein. However, the binding sites are enriched within the promoter regions of the dysregulated genes and are significantly decreased in CdLS proband, indicating an alternative role of cohesin as a transcription factor.

Appropriate segregation of chromosomes to daughter cells depends upon proper cohesion of sister chromatids during mitosis. The multiprotein cohesin complex and its regulators are key factors in this process. Intriguingly, recent work has shown that the cohesin complex also has other cellular roles, including a role in regulating gene expression. Additionally, mutations in cohesin structural and regulatory components have been linked to human multisystem developmental disorders such as Cornelia de Lange Syndrome (CdLS), but the role cohesin is playing in the pathogenesis of this disorder is unknown. To define the role that cohesin plays in regulating gene expression in human cells, we analyzed gene expression and genome-wide cohesin binding patterns in cells from normal subjects and from CdLS probands with mutations in the cohesin regulator NIPBL or in the cohesin structural component SMC1A. We found a strikingly conserved pattern of gene dysregulation in these different cell lines that correlates with disease severity and a significant correlation between gene dysregulation and cohesin binding around misexpressed genes. The observed pattern of binding and misexpression is consistent with cohesin having a putative role as a boundary/insulator interacting protein or transcription factor, the activity of which is disrupted in CdLS probands.

The molecular mechanism underlying Roberts syndrome involves loss of ESCO2 acetyltransferase activity

Roberts syndrome/SC phocomelia (RBS) is an autosomal recessive disorder with growth retardation, craniofacial abnormalities and limb reduction. Cellular alterations in RBS include lack of cohesion at the heterochromatic regions around centromeres and the long arm of the Y chromosome, reduced growth capacity, and hypersensitivity to DNA damaging agents. RBS is caused by mutations in ESCO2, which encodes a protein belonging to the highly conserved Eco1/Ctf7 family of acetyltransferases that is involved in regulating sister chromatid cohesion. We identified 10 new mutations expanding the number to 26 known ESCO2 mutations. We observed that these mutations result in complete or partial loss of the acetyltransferase domain except for the only missense mutation that occurs in this domain (c.1615T>G, W539G). To investigate the mechanism underlying RBS, we analyzed ESCO2 mutations for their effect on enzymatic activity and cellular phenotype. We found that ESCO2 W539G results in loss of autoacetyltransferase activity. The cellular phenotype produced by this mutation causes cohesion defects, proliferation capacity reduction and mitomycin C sensitivity equivalent to those produced by frameshift and nonsense mutations associated with decreased levels of mRNA and absence of protein. We found decreased proliferation capacity in RBS cell lines associated with cell death, but not with increased cell cycle duration, which could be a factor in the development of phocomelia and cleft palate in RBS. In summary, we provide the first evidence that loss of acetyltransferase activity contributes to the pathogenesis of RBS, underscoring the essential role of the enzymatic activity of the Eco1p family of proteins.

[Colombian haplotypes of the Gaucher disease-causing N370S mutation may originate from a possible common ancestral haplotype]

INTRODUCTION

Gaucher disease is a pan-ethnic condition characterised by glucosylceramide accumulation in macrophages due to glucocerebrosidase deficiency. Its gene, GBA, has been mapped to 1q21 and mutation N370S is the main cause of the disease in western populations, including Colombia.

OBJECTIVE

To asses the degree of association between N370S mutation and the alleles of five microsatellites near the mutation site in the GBA locus in nine Colombian Gaucher patients, from the Cundinamarca-Boyacá region.

MATERIALS AND METHODS

DNA from patients bearing the N370S mutation, their closest relatives, and 30 controls was taken to PCR-amplify the markers: D1S305, D1S2624, DIS2777, ITG6.6.2 and 5GC3.2. Allele frequencies were calculated, haplotypes inferred and linkage disequilibrium levels between marker alleles and N370S were also estimated.

RESULTS

Eleven N370S chromosomes were obtained. A consensus N370S haplotype consisting of the alleles: 222-314-260-301-172 (base pairs) was identified. Each allele corresponding to markers 5GC3.2, ITG6.6.2, D1S277, D1S2624 and D1S305, respectively. There was statistically significant linkage disequilibrium between the alleles of 222, 314, 260, 301 base pairs and the N370S mutation.

CONCLUSION

A conserved fraction of the haplotypes suggests that N370S may be present among patients and stem from a single ancestral chromosome for which the ethnic origin is still unclear.

Roberts syndrome is caused by mutations in ESCO2, a human homolog of yeast ECO1 that is essential for the establishment of sister chromatid cohesion

Roberts syndrome is an autosomal recessive disorder characterized by craniofacial anomalies, tetraphocomelia and loss of cohesion at heterochromatic regions of centromeres and the Y chromosome. We identified mutations in a new human gene, ESCO2, associated with Roberts syndrome in 15 kindreds. The ESCO2 protein product is a member of a conserved protein family that is required for the establishment of sister chromatid cohesion during S phase and has putative acetyltransferase activity.

Risk factors for gallstone disease in Mexicans are similar to those found in Mexican-Americans

According to epidemiological studies, gallstone disease is a very common disease in Mexican-Americans and Mexicans. However, the major risk factors for cholelithiasis in Mexicans have not been identified. We designed a case-control study in a group of Mexican subjects with and without gallstone disease confirmed by ultrasound. These subjects were prospectively studied over a three-year period. Clinical and epidemiological data were collected by means of a questionnaire. A total of 1500 subjects were included in this study: 1000 with and 500 without gallstone disease. The major risk factor in both men and women was body mass index [odds ratio (OR) 1.64 and 1.96, respectively; P < 0.008 and 0.001]. In addition, parity was an important factor in women (OR 2.17, P < 0.001), whereas age was associated with gallstone disease in men (OR 1.43, P < 0.001). We found that body mass index, parity, and age were the principal risk factors for gallstone disease in this group of Mexican subjects. These results are similar to those found in Mexican-American populations.

A novel common missense mutation G301C in the N-acetylgalactosamine-6-sulfate sulfatase gene in mucopolysaccharidosis IVA

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive lysosomal storage disorder caused by a genetic defect in N-acetylgalactosamine-6-sulfate sulfatase (GALNS). In previous studies, we have found two common mutations in Caucasians and Japanese, respectively. To characterize the mutational spectrum in various ethnic groups, mutations in the GALNS gene in Colombian MPS IVA patients were investigated, and genetic backgrounds were extensively analyzed to identify racial origin, based on mitochondrial DNA (mtDNA) lineages. Three novel missense mutations never identified previously in other populations and found in 16 out of 19 Colombian MPS IVA unrelated alleles account for 84.2% of the alleles in this study. The G301C and S162F mutations account for 68.4% and 10.5% of mutations, respectively, whereas the remaining F69V is limited to a single allele. The skewed prevalence of G301C in only Colombian patients and haplotype analysis by restriction fragment length polymorphisms in the GALNS gene suggest that G301C originated from a common ancestor. Investigation of the genetic background by means of mtDNA lineages indicate that all our patients are probably of native American descent.

Successful use of deep hypothermic circulatory arrest in pregnancy

A woman pregnant for 21 weeks underwent an emergency operation because of an aortic arch aneurysm that had ruptured into her left lung. Cardiopulmonary bypass and deep hypothermia were used and she needed 37 minutes of circulatory arrest at a core temperature of 19 degrees C. Both the mother and fetus survived, and a normal baby was delivered by cesarean section at the 39th week of gestation.

[Early and late results of myocardial revascularization after coronary thrombolysis with intravenous streptokinase in the treatment of acute myocardial infarction]

PURPOSE

To study the early and late results of patients treated initially intravenous streptokinase and then with coronary artery bypass surgery.

METHODS

One hundred and twenty one patients with acute myocardial infarction less than 6 hours duration were treated initially with intravenous streptokinase, and 1-38 days after (median 8.80 days) coronary artery bypass was undertaken. Ninety six patients were operated with extracorporeal circulation and 25 without it.

RESULTS

Overall operative mortality was 3.30% (4/121). Reoperations due to bleeding was necessary in 3.30% (4/121). Late mortality was 5.40% with survival probability of 94.60% after 36 months and 92.30% after 70 months. Late morbidity events in terms of angina and cardiac insufficiency demonstrated that 7 patients had angina, 4 cardiac insufficiency and two angina and cardiac insufficiency; probability to be free from these events was 88.20% after 46 months and 66.40% after 70 months.

CONCLUSION

Coronary artery bypass surgery after intravenous streptokinase can be undertaken with security and excellent early and late results.