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A scarlet fever outbreak occurred in Hong Kong in 2011. The majority of cases resulted in the isolation of Streptococcus pyogenes emm12 with multiple antibiotic resistances. Phylogenetic analysis of 22 emm12 scarlet fever outbreak isolates, 7 temporally and geographically matched emm12 non–scarlet fever isolates, and 18 emm12 strains isolated during 2005–2010 indicated the outbreak was multiclonal. Genome sequencing of 2 nonclonal scarlet fever isolates (HKU16 and HKU30), coupled with diagnostic polymerase chain reaction assays, identified 2 mobile genetic elements distributed across the major lineages: a 64.9-kb integrative and conjugative element encoding tetracycline and macrolide resistance and a 46.4-kb prophage encoding superantigens SSA and SpeC and the DNase Spd1. Phenotypic comparison of HKU16 and HKU30 with the S. pyogenes M1T1 strain 5448 revealed that HKU16 displays increased adherence to HEp-2 human epithelial cells, whereas HKU16, HKU30, and 5448 exhibit equivalent resistance to neutrophils and virulence in a humanized plasminogen murine model. However, in contrast to M1T1, the virulence of HKU16 and HKU30 was not associated with covRS mutation. The multiclonal nature of the emm12 scarlet fever isolates suggests that factors such as mobile genetic elements, environmental factors, and host immune status may have contributed to the 2011 scarlet fever outbreak.

A microprocessor based TENS device is developed which utilizes a spatial procedure in the administration of electrical fields to actively interfere with pain signals reaching the brain. This unusual design also has the advantage of requiring the frequency characteristics of the electrical waveform produced to be optimally tuned to the mechanical impedance properties of the skin/tissue. Hence a much more efficient procedure for the transfer of electrical energy from the TENS device to the human tissue is provided. Data are presented involving patients from the Dayton VA Medical Center in Ohio, USA being tested with this new microprocessor system compared to the treatment obtained via a traditional stimulator.

A simple and convenient method of transport of serum in the form of protein disc on water resistant medium is described. The method was used to study the stability of thyroxine (T4), cortisol, thyroid stimulating hormone (TSH), parathormone (PTH) and insulin. The mean recoveries of these hormones were between 98 and 100%. The standard deviations of duplicates of assays for protein disc samples were comparable to that of serum samples except in assays using enzyme immunoassay techniques. The correlation coefficients of the results between the serum and protein disc samples were satisfactory ranging from 0.86–0.99. The proposed method could be used for interlaboratory referral of serum.

The effect of serum. methanol/water, and detergents on the dissociation of the antigens thyroxin (T4) and triiodothyronine (T3) from immobilized antibody was investigated by an antigen binding technique and scanning electron microscopy. The antibody coatings immobilized on the different polymeric substrates showed varying degrees of denaturation and desorption due to detergents but were unaffected by a 60 40 (by volume) mixture of methanol/water after various washington procedures. The factors influencing the dissociation and its relevance to recycling immunoassay are discussed. It was found that nonspecific binding of serum proteins to the antibody coatings wa a major caused of deterioration in antibody binding capacity.

Variation of solid-phase antibody concentration could give rise to poor intra- and interassay precision. A new method to detect this variation is reported. Pooled sera with thyroxine (T4) values at the low, medium, and high ranges were assayed in duplicate using anti-T4-coated polystyrene beads. The antigen-antibody complexes were dissociated with methanol-water mixture and the antibodies re-used for subsequent T4 assays in which the same beads were used with the same set of standards and pooled sera. A second set of assays using randomised beads after each assay-wash cycle were also carried out. The variations in weights and surface structures of the beads were also studied. The variation of T4 results of group methods using polyethylene glycol in an external quality control program was also compared with that of covalently linked solid-phase particulate antibody methods over 2 periods. The experimental results showed that there was bead-to-bead variation of antibody concentration which could give rise to poor precision. Rigorous control of the immobilised antibody concentration could further improve the assay performance.