Multidrug-resistant tuberculosis in South Korea: a retrospective analysis of national registry data in 2011-2015

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) poses a threat to public health as a result of high treatment costs and unsatisfactory outcomes.OBJECTIVE: To elucidate trend, demographic and clinical characteristics and treatment outcomes of patients with MDR-TB between 2011 and 2015 in South Korea.METHOD: Data of patients with MDR-TB diagnosed between 1 January 2011 and 31 December 2015 were retrieved from the nationwide Internet-based TB notification system and analysed retrospectively.RESULTS: During the study period, 5192 MDR-TB patients were notified. We identified an increasing number of MDR-TB patients among foreign populations (from 1.3% to 7.7%), decreasing resistance rates to other anti-TB drugs (e.g., resistance to pyrazinamide, from 40.9% to 28.2%), a decreasing interval from treatment initiation to negative conversion of sputum culture (from 165.7 to 103.7 days) and shortening of treatment duration (719.7 to 613.2 days). However, treatment success rates did not change, and had an average of 65.7%.CONCLUSION: Despite decreasing resistance rates to other drugs and faster treatment responses, treatment outcomes did not improve during the study period. Strict management of MDR-TB patients on treatment should be adopted to improve treatment outcomes.

A phase I study of Onyx-015, an E1B attenuated adenovirus, administered intratumorally to patients with recurrent head and neck cancer

An E1B 55 kDa gene-deleted adenovirus, Onyx-015, which reportedly selectively replicates in and lyses p53-deficient cells, was administered by a single intratumoral injection to a total of 22 patients with recurrent head and neck cancer. The objectives of this Phase I study were to determine the safety, feasibility, and efficacy of this therapy and determine any correlation to p53 status. Six cohorts were investigated with a dose escalation from 10(7)-10(11) plaque-forming units. Toxicity was assessed using NCIC criteria. Tumor response was assessed by clinical and radiological measurement. Blood samples were taken to detect adenovirus DNA and neutralizing antibody to adenovirus. Tumor biopsies were taken to detect adenovirus by in situ hybridization. Treatment was well tolerated, with the main toxicity being grade 1/2 flu-like symptoms. Dose-limiting toxicity was not reached at the highest dose of 10(11) plaque-forming units. Twenty-one of the 22 patients treated showed an increase in neutralizing antibody to adenovirus. In situ hybridization showed viral replication in 4 of 22 patients treated, all of whom had mutant p53 tumors. Using conventional response criteria, no objective responses were observed. However, magnetic resonance imaging scans were suggestive of tumor necrosis at the site of viral injection in five patients, three of whom were classified using nonconventional criteria as partial responders, and two of whom were classified using nonconventional criteria as minor responders. Of these five cases, four had mutant p53 tumors. The response duration for the three partial responders was 4, 8, and 12 weeks. An additional eight patients had stable disease in the injected tumors lasting from 4-8 weeks. These preliminary results show that intratumoral administration of Onyx-015 is feasible, well tolerated, and associated with biological activity. Further investigation of Onyx-015, particularly with a more frequent injection protocol and in combination with systemic chemotherapy, is warranted.

Expression analysis of the PMP22 gene in glioma and osteogenic sarcoma cell lines

Previously we reported the amplification of the peripheral myelin protein 22 (PMP22) gene in cell lines of human osteogenic and glioma tumors. PMP22 normally is expressed at high levels in Schwann cells of the peripheral nervous system and is suggested to function as a structural protein of the myelin sheath. One of the most common inherited peripheral neuropathies, Charcot-Marie-Tooth Type 1A (CMT1A), is associated with a duplication of a 1.5-Mb DNA region on chromosome 17p11.2 - p12 containing PMP22. On the other hand, PMP22 is identical to gas3, whose expression is induced in growth-arresting NIH3T3-fibroblasts and is thought to play a role in cell proliferation. The precise role of gas3/PMP22 remains to be determined. Here we show that in the tumor cell lines RH30 and SF763 the amplified region including PMP22 comprises the whole 1.5-Mb CMT1A region. We could prove expression of PMP22 by reverse transcriptase-polymerase chain reaction (RT-PCR) and discovered an unusual PMP22 transcript in these tumor cell lines. Western blot analyses resulted in detection of a 22-kDa protein by the PMP22-specific antibody 558/2 and in exclusion of myelin protein zero (MPZ) expression in these cell lines.

Preparation of phosphopeptides derived from alpha s-casein and beta-casein using immobilized glutamic acid-specific endopeptidase and characterization of their calcium binding

Phosphopeptides that were derived from alpha s-CN or beta-CN were prepared with immobilized glutamic acid-specific endopeptidase, and their Ca2+ binding was characterized. alpha s-Casein or beta-CN was hydrolyzed in a fluidized bed bioreactor containing 2 ml of immobilized glutamic acid-specific endopeptidase by recirculating 20 ml of alpha s-CN or beta-CN solution (10 mg/ml in 50 mM Tris.HCl and 0.02% NaN3, pH 8.0) for 3 h at 20 degrees C. The molecular masses of casein peptides were monitored by SDS-PAGE. Each hydrolysate was applied to an anion-exchange column using stepwise elution with various concentrations of KCl to separate peptides. The casein phosphopeptide content of the elution profile was monitored by analysis of protein and P concentrations. Calcium binding in phosphopeptide-enriched fractions was determined by CaCl2 titration and measurement of free Ca2+ with a Ca-selective electrode. The electrophoresis patterns showed four major peptides having molecular masses of 10.8, 9.0, 6.6, and 3.6 kDa in the alpha s-CN hydrolysate and 9.3, 8.2, and 6.2 kDa in the beta-CN hydrolysate. The highest concentrations of P were detected in the fractions that eluted with 0.4 and 0.5 M KCl for the alpha s-CN hydrolysate and with 0.4 M KCl for the beta-CN hydrolysate. The calcium-binding ability was found only in the fraction that was eluted with 0.4 M KCl; the maximum Ca2+ binding and the apparent binding constant were 0.24 mmol/mg of protein and 75 M-1, and 0.14 mmol/mg of protein and 148 M-1, respectively. alpha s-Casein phosphopeptides had different patterns for Ca2+ binding than did beta-CN phosphopeptides as the total Ca concentration was increased. Calcium binding to these casein phosphopeptides differed from that previously characterized for the tryptic peptides.

Calcium binding of phosphopeptides derived from hydrolysis of alpha s-casein or beta-casein using immobilized trypsin

Calcium binding to casein phosphopeptides that were derived from alpha s-CN or beta-CN was studied. Purified alpha s-CN or beta-CN was prepared from fresh skim milk using an anion-exchange column. Peptides were prepared by casein hydrolysis using a fluidized bed bioreactor containing 2 ml of immobilized trypsin (activity: 49.4 U/g of beads). The disappearance of intact protein and the appearance of products of low molecular mass were monitored by SDS-PAGE. alpha s-Casein and beta-CN hydrolysates were loaded on an anion-exchange column, followed by stepwise elution with 0, 0.1, 0.2, 0.4, and 0.5 M KCl in equilibration buffer to separate the phosphopeptides from the other casein peptides. Protein and P were measured in the elution peaks. Calcium binding to each fraction was determined with a Ca-selective electrode. Electrophoresis showed that intact proteins were hydrolyzed rapidly, and peptides appeared on the gel in greater concentrations as the incubation time increased. The major products were a main band with a molecular mass of 6.2 kDa from beta-CN hydrolysates and a series of bands from 4.0 to 12.8 kDa from alpha s-CN hydrolysate. The greatest yield and concentration of phosphate from beta-CN hydrolysate were found in the peak that eluted with 0.4 M KCl in equilibration buffer and for alpha s-CN in the peak that eluted with 0.1 M KCl. The alpha s-CN phosphopeptides showed greater Ca2+ binding than the phosphopeptides from beta-CN. Separation of casein phosphopeptides using anion exchange was not specific. However, results showed that each peak containing high concentrations of phosphate had Ca(2+)-binding ability. Further characterization of these casein phosphopeptides might result in a Ca-complexing food ingredient.

Immunogenicity of casein phosphopeptides derived from tryptic hydrolysis of beta-casein

The immunogenicity of phosphopeptides derived from tryptic hydrolysis of beta-casein (CN) was investigated in a rat model system. The titers of specific immunoglobulin (Ig)G and IgE antibodies made in response to intraperitoneal sensitization to beta-CN, casein phosphopeptides, and skim milk proteins were examined using indirect and amplified indirect ELISA, respectively. Serum IgG antibodies from rats injected with beta-CN were significantly more reactive to beta-CN, casein phosphopeptides, and skim milk proteins coated on microtiter plate wells than were the IgG antibodies generated in rats that had been subjected to other treatments. A significant difference in titers because of the time of sampling (14 or 21 d postinjection) was noted for IgE but not for IgG. Rats that were injected with casein phosphopeptides did not produce IgG antibodies that crossreacted with either skim milk proteins or beta-CN. Specific antibody levels for the IgE class rarely exceeded those of unimmunized controls. The findings suggest that immunogenicity of the phosphopeptides was reduced compared with that of native beta-CN and skim milk proteins.

The peripheral myelin protein 22 kDa (PMP22) gene is amplified in cell lines derived from glioma and osteogenic sarcoma

Two glioma (SF188, SF763) and two osteogenic sarcoma cell lines (RH30, SA1) were examined for the presence of an amplification of the PMP22 gene by means of fluorescence in situ hybridization (FISH). In one cell line of both cell types, we found about 10 copies of the PMP22 (peripheral myelin protein 22 kDa) gene, located on different marker chromosomes within homogeneously staining regions. Surrounding chromosome 17p material was found to be coamplified, but coamplification of TP53 (17p13) and erbB2/Her2 (17q11.12) were excluded by FISH for both cell lines, SF763 and RH30. This is the first report of a PMP22 amplification in cell lines derived from human tumors.