Taiwan National Newborn Screening Program by Tandem Mass Spectrometry for Mucopolysaccharidoses Types I, II, and VI.

OBJECTIVE: To evaluate the initial cutoff values, rates of screen positives, and genotypes for the large-scale newborn screening program for multiple mucopolysaccharidoses (MPS) in Taiwan. STUDY DESIGN: More than 100 000 dried blood spots were collected consecutively as part of the national Taiwan newborn screening programs. Enzyme activities were measured by tandem mass spectrometry from dried blood spot punches. Genotypes were obtained when a second newborn screening specimen again had a decreased enzyme activity. Additional clinical evaluation was then initiated based on enzyme activity and/or genotype. RESULTS: Molecular genetic analysis for cases with low enzyme activity revealed 5 newborns with pathogenic alpha-L-iduronidase mutations, 3 newborns with pathogenic iduronate-2-sulfatase mutations, and 1 newborn was a carrier of an arylsulfatase B mutation. Several variants of unknown pathogenic significance were also identified, most likely causing pseudodeficiency. CONCLUSIONS: The highly robust tandem mass spectrometry-based enzyme assays for MPS-I, MPS-II, and MPS-VI allow for high-throughput newborn screening for these lysosomal storage disorders. Optimized cutoff values combined with second tier testing could largely eliminate false-positive results. Accordingly, newborn screening for these lysosomal storage disorders is possible.

Detecting 22q11.2 Deletion Syndrome in Newborns with Low T Cell Receptor Excision Circles from Severe Combined Immunodeficiency Screening.

OBJECTIVE: Based on experiences and results from newborn screening for severe combined immunodeficiency (SCID), we evaluated the occurrence of chromosome 22q11.2 deletion syndrome (22q11.2DS) in newborns with different T cell receptor excision circles (TREC) results and established a second tier genetic test for 22q11.2DS. STUDY DESIGN: Recalled dried blood spots from 486 newborns with TREC results <90 copies/uL were tested from the SCID newborn screening. Quantitative real-time polymerase chain reaction assay was used to detect the copy number of TBX1 and HIRA genes by simple DNA extraction method. Multiplex ligation dependent probe amplification was used for further confirmation. RESULTS: Four hundred sixty-eight cases were considered negative because their haploid copy number of TBX1 and HIRA genes was >0.75. Eighteen cases with TBX1 and/or HIRA gene copy number <0.75 were suspected as positive, and 13 cases were further confirmed with 22q11.2DS. Detection rates of 22q11.2DS were 10.7% (6/56) in TREC <30 copies, 6.8% (9/132) in <50 TREC copies, 4.6% (12/260) in <70 TREC copies, and 2.7% (13/486) in <90 TREC copies. CONCLUSIONS: 22q11.2DS detection can be incorporated into the second-tier assay in subjects with low TREC copies in SCID screening. The dried blood spot methods were feasible for 22q11.2DS newborn screening.

Portación nasal deStaphylococcus aureus y sus perfiles de resistencia a antibióticos en niños que viven en zonas de gran altitud del sudoeste de China / Staphylococcus aureus nasal carriage and its antibiotic resistance profiles in children in high altitude areas of Southwestern China

Antecedentes/Objetivo. Describir el perfil epidemiológico de la portación nasal de cepas de Staphylococcus aureus (S. aureus), su resistencia a antibióticos y la presencia de los genes de leucocidina de Panton-Valentine (LPV) y mecA en niños en edad escolar que viven en zonas de gran altitud del sudoeste de China. Métodos. En el estudio transversal, se analizaron hisopados nasales de estudiantes a fin de detectar S. aureus. Se realizó la prueba de la reacción en cadena de la polimerasa (RCP) para identificar los genes de LPV y mecA. Resultados. Del total de 314 niños, se detectó S. aureus en el 5,10% (16/314). La resistencia de las cepas aisladas a la penicilina, eritromicina, clindamicina, rifampicina y cefoxitina fue del 100%, 81,3%, 81,3%, 0,0% y 6,3%, respectivamente. Ninguna de las cepas mostró resistencia a la vancomicina. Se detectó la expresión del gen mecA en 3 cepas aisladas, y 10 cepas aisladas dieron resultado positivo para el gen de LPV. Conclusión. Se detectó S. Aureus en el 5,10% (16/314) de la población del estudio; el 0,96% (3 /314) presentó S. Aureus resistente a la meticilina (SARM). Además, se detectó la expresión de los genes de LPV y mecA en 10 y 3 cepas aisladas, respectivamente.

Background/Aim. To describe the epidemiological profile of nasal carriage of Staphylococcus aureus (S. aureus) strains, its antibiotic resistance and mecA and Panton Valentine leukocidin (PVL) genes presence, in school children residing in high altitude areas of Southwestern China. Methods. The cross sectional study screened nasal swabs taken from students for S. aureus. PCR was performed to identify mecA and PVL genes. Results. Of the total 314 children 5.10% (16/314) was detected S. aureus. The resistance of isolated strains to penicillin, erythromycin, clindamycin, rifampicin and cefoxitin was 100%, 81.3%, 81.3%, 0.0%, and 6.3% respectively. No strains demonstrated resistance to vancomycin; expression of mecA gene was detected in 3 isolates and 10 isolates were PVL-positive. Conclusion. S. aureus was detected in 5.10% (16/314) of the study population; 0.96% (3/314) had methicillin resistant S. aureus (MRSA); expression of the mecA and PVL genes were detected in 3 and 10 isolates respectively.

Staphylococcus aureus nasal carriage and its antibiotic resistance profiles in children in high altitude areas of Southwestern China. / Portación nasal de Staphylococcus aureus y sus perfiles de resistencia a antibióticos en niños que viven en zonas de gran altitud del sudoeste de China.

BACKGROUND/AIM: To describe the epidemiological profile of nasal carriage of Staphylococcus aureus (S. aureus) strains, its antibiotic resistance and mecA and Panton Valentine leukocidin (PVL) genes presence, in school children residing in high altitude areas of Southwestern China. METHODS: The cross sectional study screened nasal swabs taken from students for S.aureus. PCR was performed to identify mecA and PVL genes. RESULTS: Of the total 314 children 5.10% (16/314) was detected S.aureus. The resistance of isolated strains to penicillin, erythromycin, clindamycin, rifampicin and cefoxitin was 100%, 81.3%, 81.3%, 0.0%, and 6.3% respectively. No strains demonstrated resistance to vancomycin; expression of mecA gene was detected in 3 isolates and 10 isolates were PVL-positive. CONCLUSION: S. aureus was detected in 5.10% (16/314) of the study population; 0.96% (3/314) had methicillin resistant S.aureus (MRSA); expression of the mecA and PVL genes were detected in 3 and 10 isolates respectively.

ANTECEDENTES Y OBJETIVO: Describir el perfil epidemiológico de la portación nasal de cepas de Staphylococcus aureus (S. aureus), su resistencia a antibióticos y la presencia de los genes de leucocidina de Panton-Valentine (LPV) y mecA en niños en edad escolar que viven en zonas de gran altitud del sudoeste de China. MÉTODOS: Describir el perfil epidemiológico de la portación nasal de cepas de Staphylococcus aureus (S. aureus), su resistencia a antibióticos y la presencia de los genes de leucocidina de Panton-Valentine (LPV) y mecA en niños en edad escolar que viven en zonas de gran altitud del sudoeste de China. RESULTADOS: Del total de 314 niños, se detectó S. aureus en el 5,10% (16/314). La resistencia de las cepas aisladas a la penicilina, eritromicina, clindamicina, rifampicina y cefoxitina fue del 100%, 81,3%, 81,3%, 0,0% y 6,3%, respectivamente. Ninguna de las cepas mostró resistencia a la vancomicina. Se detectó la expresión del gen mecA en 3 cepas aisladas, y 10 cepas aisladas dieron resultado positivo para el gen de LPV. CONCLUSIÓN: Se detectó S. Aureus en el 5,10% (16/314) de la población del estudio; el 0,96% (3 / 314) presentó S. Aureus resistente a la meticilina (SARM). Además, se detectó la expresión de los genes de LPV y mecA en 10 y 3 cepas aisladas, respectivamente.

Selective, direct activation of high-conductance, calcium-activated potassium channels causes smooth muscle relaxation.

High-conductance calcium-activated potassium (Maxi-K) channels are present in smooth muscle where they regulate tone. Activation of Maxi-K channels causes smooth muscle hyperpolarization and shortening of action-potential duration, which would limit calcium entry through voltage-dependent calcium channels leading to relaxation. Although Maxi-K channels appear to indirectly mediate the relaxant effects of a number of agents, activators that bind directly to the channel with appropriate potency and pharmacological properties useful for proof-of-concept studies are not available. Most agents identified to date display significant polypharmacy that severely compromises interpretation of experimental data. In the present study, a high-throughput, functional, cell-based assay for identifying Maxi-K channel agonists was established and used to screen a large sample collection (>1.6 million compounds). On the basis of potency and selectivity, a family of tetrahydroquinolines was further characterized. Medicinal chemistry efforts afforded identification of compound X, from which its two enantiomers, Y and Z, were resolved. In in vitro assays, Z is more potent than Y as a channel activator. The same profile is observed in tissues where the ability of either agent to relax precontracted smooth muscles, via a potassium channel-dependent mechanism, is demonstrated. These data, taken together, suggest that direct activation of Maxi-K channels represents a mechanism to be explored for the potential treatment of a number of diseases associated with smooth muscle hyperexcitability.