Deep learning for bias correction of MJO prediction

Producing accurate weather prediction beyond two weeks is an urgent challenge due to its ever-increasing socioeconomic value. The Madden-Julian Oscillation (MJO), a planetary-scale tropical convective system, serves as a primary source of global subseasonal (i.e., targeting three to four weeks) predictability. During the past decades, operational forecasting systems have improved substantially, while the MJO prediction skill has not yet reached its potential predictability, partly due to the systematic errors caused by imperfect numerical models. Here, to improve the MJO prediction skill, we blend the state-of-the-art dynamical forecasts and observations with a Deep Learning bias correction method. With Deep Learning bias correction, multi-model forecast errors in MJO amplitude and phase averaged over four weeks are significantly reduced by about 90% and 77%, respectively. Most models show the greatest improvement for MJO events starting from the Indian Ocean and crossing the Maritime Continent.

Bovine spongiform encephalopathy surveillance in the Republic of Korea

National surveillance for bovine spongiform encephalopathy (BSE) began in the Republic of Korea (ROK) in 1996. Surveillance programmes changed overtime to comply with the guidelines of the World Organisation for Animal Health (OIE). Bovine spongiform encephalopathy was designated as a notifiable disease in 1997. From July 2008, the BSE surveillance programme was intensified to test cattle in designated high-risk populations more effectively. New measures included the compulsory testing of all non-ambulatory cattle at abattoirs, and encouraging the testing of all dead cattle examined and recorded under the Mutual Aid Insurance Scheme (fallen stock). In addition, there was a vigorous search for animals suspected of being clinically infected. As a result, a total of 426,919 OIE points were achieved over a period of seven consecutive years to the end of October 2009. This enabled the submission of a successful application to the OIE in 2010 for recognition of the ROK's BSE disease status as being one of controlled risk, in accordance with Chapter 11.5. of the OIE Terrestrial Animal Health Code.

Interferon-γ induced by in vitro re-stimulation of CD4+ T-cells correlates with in vivo FMD vaccine induced protection of cattle against disease and persistent infection

The immune defense against FMDV has been correlated to the antibody mediated component. However, there are occasions when some animals with high virus neutralising (VN) antibody are not protected following challenge and some with low neutralising antibody which do not succumb to disease. The importance of cell mediated immunity in clinical protection is less clear and so we investigated the source and production of interferon-gamma (IFN-γ) in re-stimulated whole blood of FMDV immunized cattle and its correlation to vaccine induced protection and FMDV persistence. We were able to show a positive correlation between IFN-γ response and vaccine induced protection as well as reduction of long term persistence of FMD virus. When combining this IFN-γ response in re-stimulated blood with virus neutralizing antibody titer in serum on the day of challenge, a better correlation of vaccine-induced protection with IFN-γ and VN antibody was predicted. Our investigations also showed that CD4+ T-cells are the major proliferating phenotype and IFN-γ producing cells.

Antimicrobial resistance of enterococci isolated from mastitic bovine milk samples in Korea

The aim of this study was to determine the antimicrobial resistance of various species of enterococci isolated from mastitic bovine milk samples. A total of 105 enterococci isolates were examined: Enterococcus faecalis (n = 47), Enterococcus faecium (n = 39), Enterococcus gallinarum (n = 6), Enterococcus avium (n = 6), Enterococcus hirae (n = 5) and Enterococcus durans (n = 2). All the isolates were susceptible to ampicillin, gentamicin and vancomycin, and only a single E. hirae isolate was resistant to ampicillin. In general, the most frequently observed resistance among the enterococcal isolates was to tetracycline (69.5%), followed by penicillin (64.7%), erythromycin (57.1%) and cephalothin (44.7%). A similar antimicrobial resistance pattern was observed among individual species except E. durans, which exhibited only tetracycline resistance. Resistance observed among isolates of E. hirae and E. gallinarum was almost as high as E. faecium and E. faecalis. Of 105 isolates, only six (5.7%) strains of E. faecium were susceptible to all the antimicrobials tested and about 52% (55/105) showed resistance to more than three antimicrobials. The most common multiple resistance pattern was penicillin, tetracycline and erythromycin, which was observed in 32 of 105 (30.4%) isolates. This study demonstrates that enterococcal isolates belonging to minor species showed antimicrobial resistance rates as high as those of E. faecium and E. faecalis, and that monitoring of antimicrobial resistance should not be restricted only to those two major species.

Comparative histopathological characteristics of highly pathogenic avian influenza (HPAI) in chickens and domestic ducks in 2008 Korea

We compared characteristic lesions occurring in chickens and domestic ducks naturally infected with H5N1 HPAI virus in April and May 2008. Infected chickens generally exhibited pale-green, watery diarrhoea, depression, neurological signs and cyanosis of wattles and combs, and infected ducks generally exhibited neurological signs and watery diarrhoea. Gross petechial or ecchymotic haemorrhage affected the heart, proventriculus, liver, muscle, fat, and pancreas in chickens, and muscle in ducks. Necrotic foci were primarily present in the pancreas of both species and in the heart of domestic ducks. Histopathologically, chickens exhibited multifocal encephalomalacia, multifocal lymphohistiocytic myocarditis, multifocal necrotic pancreatitis and haemorrhage of several organs and tissues; ducks exhibited lymphohistiocytic meningoencephalitis with multifocal haemorrhages, multifocal necrotic pancreatitis, and severe necrotic myocarditis with mineralisation. The characteristic histopathologic findings of 2008 HPAI were multifocal encephalomalacia and necrotic pancreatitis accompanied by lymphohistiocytic myocarditis, and haemorrhage in various organs and tissues in chickens, whereas in ducks, they were severe necrotic myocarditis with mineralisation and necrotic pancreatitis, accompanied with lymphohistiocytic meningoencephalitis. The high mortality of domestic ducks may be intimately associated with heart failure resulting from increased H5N1 HPAI viral cardiotropism.

Antibiogram and coagulase diversity in staphylococcal enterotoxin-producing Staphylococcus aureus from bovine mastitis

We investigated antibiogram and coagulase gene diversity in staphylococcal enterotoxin (StE)-producing Staphylococcus aureus isolated from raw milk samples of cows infected with mastitis from 140 dairy farms in Korea between 1997 and 2004. Of the 696 Staph. aureus isolates collected in this study, 164 isolates (23.6%) produced one or more staphylococcal enterotoxins (A to D), and 19 isolates (2.7%) were methicillin-resistant. The percentage of StE-producing Staph. aureus (SES) isolates resistant to methicillin, kanamycin, neomycin, amikacin, and tetracycline was greater than that of non-SES. Ten coagulase genotype patterns were observed, including 4 main types comprising I (25.4%), II (13.9%), VII (13.2%), and VIII (17.8%). More than 4 Staph. aureus types were isolated from each of 82 dairy farms in different geographic locations, and only 1 coagulase genotype pattern was observed in 39 of the herds (47.6%). There was no significant correlation between coagulase genotypes harbored by Staph. aureus and their specific StE type. The percentage of isolates producing major StE types (A, B, AC, and ABCD) and being resistant to cephalothin and methicillin was greater among the Staph. aureus isolates with the 4 predominant coagulase genotypes (I, II, VII, and VIII) than among the isolates harboring the 6 rare coagulase types (III, IV, V, VI, IX, and X). Based on coagulase gene polymorphisms, our data indicate that a broad distribution of identical or closely related enterotoxin-producing Staph. aureus strains seem to contribute to bovine mastitis in the Republic of Korea.

Pathogenic characteristics of the Korean 2002 isolate of foot-and-mouth disease virus serotype O in pigs and cattle

Experimental infection of susceptible cattle and pigs showed that the O/SKR/AS/2002 pig strain of foot-and-mouth disease virus (FMDV) causes an infection that is highly virulent and contagious in pigs but very limited in cattle. Pigs directly inoculated with, or exposed to swine infected with, strain O/SKR/AS/2002 showed typical clinical signs, including gross vesicular lesions in mouth and pedal sites. In addition, FMDV was isolated from, and FMDV genomic RNA was detected in, blood, serum, nasal swabs and oesophageal-pharyngeal (OP) fluid early in the course of infection. Antibodies against the non-structural protein (NSP) 3ABC were detected in both directly inoculated and contact pigs, indicating active virus replication. In contrast, the disease in cattle was atypical. After inoculation, lesions were confined to the infection site. A transient viraemia occurred 1 and 2 days after inoculation, and this was followed by the production of antibodies to NSP 3ABC, indicating subclinical infection. No clinical disease was seen, and no antibodies to NSP 3ABC were present in contact cattle. Additionally, no virus or viral nucleic acid was detected in blood, nasal swab and OP fluid samples from contact cattle. Thus, the virus appeared not to be transmitted from infected cattle to contact cattle. In its behaviour in pigs and cattle, strain O/SKR/AS/2002 resembled the porcinophilic FMDV strain of Cathay origin, O/TAW/97. However, the latter, unlike O/SKR/AS/2002, has reduced ability to grow in bovine-derived cells. The porcinophilic character of O/TAW/97 has been attributed to a deletion in the 3A coding region of the viral genome. However, O/SKR/AS/2002 has an intact 3A coding region.

Comparison of antibiogram, staphylococcal enterotoxin productivity, and coagulase genotypes among Staphylococcus aureus isolated from animal and vegetable sources in Korea

Staphylococcal food poisoning is caused by enterotoxin-producing Staphylococcus aureus. We investigated the prevalence of such organisms in samples of bovine mastitic milk (n = 714), raw meat (n = 139), and vegetables (n = 616). We determined the degrees of relatedness of isolates as indicated by antibiogram, staphylococcal enterotoxin (SE) productivity, and coagulase gene restriction fragment length polymorphism analysis. We examined 297 S. aureus isolates and found SE production in 57 (31.8%), 4 (7.8%), and 49 (73.1%) isolates from raw milk, raw meat, and vegetables, respectively. A high proportion of the isolates obtained from milk produced more than two types of toxins (mainly SEA, SEB, and/or SEC), whereas isolates from raw meat and vegetables primarily produced SEA alone. Most isolates were sensitive to cephalothin (97.6%), gentamicin (80.8%), erythromycin (79.5%), and tetracycline (72.7%), but were resistant to penicillin (90.2%) and ampicillin (88.9%). The proportion of antibiotic-resistant isolates differed according the source of the bacteria; the milk and vegetable isolates were more resistant to penicillin and ampicillin than were the meat isolates (P < 0.05), whereas tetracycline resistance was limited to the milk and vegetables isolates. The coagulase genotypes (I to XII) varied with the source of the organism, and only a few genotypes prevailed in each source: II (42.4%) and IV (24%) types in isolates from milk, IX (35.3%) and XI (45%) from raw meat, and III (40.3%) and XII (32.8%) from vegetables. These findings suggest that remarkable differences exist in antibiogram, SE productivity, and coagulase genotypes, resulting in limited clonal transmission of S. aureus into various food sources. As enterotoxin production only occurs when S. aureus grows to high numbers, staphylococcal food poisoning can be prevented by proper refrigeration.

Development of an epitope-blocking-enzyme-linked immunosorbent assay to differentiate between animals infected with and vaccinated against foot-and-mouth disease virus

An epitope-blocking ELISA (EB-ELISA) was developed to distinguish animals infected with foot-and-mouth-disease (FMDV) from those immunized with commercial vaccines. The assay used monoclonal antibodies to target the 3B core repeat motif (QKPLK) and purified recombinant 3AB proteins from the major B cell line epitopes of FMDV. Sera from uninfected and regularly vaccinated cattle, pigs, goats, and sheep (raised in FMDV free areas) were screened to evaluate the specificity of the EB-ELISA. The specificity scores of the assays were 99.8-100% and 100%, respectively. Reference sera from cattle, pigs, goats, and sheep experimentally infected with FMDV tested positive, with only a single exception. Antibodies formed in response to FMDV 3B appeared 1 week after infection and persisted at high levels for more than 8 weeks within the sera collected from serial bleeding of animals infected with FMDV O/SKR/2000. The EB-ELISA was used to differentiate between farms vaccinated against and those infected with FMDV (FMDV Asia serotype) during the 2005 epidemic in Mongolia by detecting antibodies against the FMDV Asia serotype in outbreak farms. This EB-ELISA method shows promise as an effective tool for FMDV control and eradication.

Application of a New Portable Microscopic Somatic Cell Counter with Disposable Plastic Chip for Milk Analysis

The somatic cell count (SCC) is one of the international standards for monitoring milk quality, and it is a useful indicator of mastitis. The current reference method for determining the SCC in raw milk is direct microscopic analysis, but this method requires well-trained staff to maintain its accuracy and reproducibility. To overcome these inconveniences, we developed a portable system (the C-reader system) that utilizes the capillary flow of a microfluidic chamber by surface modification of the hydrophilicity. The microfluidic technology of disposable microchips allows for low consumption of reagents, and a combination of ready-to-use reagents makes the daily work easier. The repeatability test of the C-reader using 10 composite bovine milk samples satisfied the recommended values for SCC equipment. In addition, an acceptable accuracy level of the natural logarithmic-transformed SCC [ln(SCC/1,000): +/- 0.059 to 0.112] was achieved using composite raw milk samples and various somatic cell standard solutions from the American Eastern Laboratory and the Korean National Veterinary Research and Quarantine Service. After testing 875 composite milk samples, the C-reader showed a high correlation coefficient (R2 = 0.935 to 0.964) and a low mean difference value in log-transformed SCC (-0.088 to 0.004) compared with 3 automatic commercialized somatic cell counters (Fossomatic 4000, Somacount 150, and Somascope). In conclusion, the C-reader system is a new, easy-to-use automatic on-farm method with acceptable repeatability and accuracy for measuring SCC in large dairies and smaller laboratories.

Enhanced immune response with foot and mouth disease virus VP1 and interleukin-1 fusion genes

The capsid of the foot and mouth disease (FMD) virus carries the epitopes that are critical for inducing the immune response. In an attempt to enhance the specific immune response, plasmid DNA was constructed to express VP1/interleukin-1α (IL-1α) and precursor capsid (P1) in combination with 2A (P1-2A)/IL-1α under the control of the human cytomegalovirus (HCMV) immediateearly promoter and intron. After DNA transfection into MA104 (monkey kidney) cells, Western blotting and an immunofluorescence assay were used to confirm the expression of VP1 or P1-2A and IL-1α. Mice were inoculated with the encoding plasmids via the intradermal route, and the IgG1 and IgG2a levels were used to determine the immune responses. These results show that although the immunized groups did not carry a high level of neutralizing antibodies, the plasmids encoding the VP1/IL-1α, and P1-2A/IL-1α fused genes were effective in inducing an enhanced immune response.

Development of a Lightcycler-based reverse transcription polymerase chain reaction for the detection of foot-and-mouth disease virus

One step TaqMan real-time reverse transcription polymerase chain reaction (R/T RT-PCR) using a set of primers/probes was developed for the detection of foot-and-mouth disease (FMD) virus. The gene-specific probes labeled fluorogen for the internal ribosomal entry site, Leader sequence and 2B regions were used to detect FMD virus (FMDV). This assay specifically detected FMDV both in cell culture preparations and clinical samples, and was capable of distinguishing FMD from other viral diseases similar to clinical signs (swine vesicular disease, vesicular stomatitis and bovine viral diarrhea). This assay was shown to be 1000-fold more sensitive than the conventional RT-PCR method. The detection limits of this assay was 1 TCID(50)/ml of the FMDV RNA concentration. Quantification was obtained by a standard curves plotting threshold cycle values versus known infectivity titer. The assay was sensitive, specific and rapid enough to detect FMDV RNA genome in probang samples. As such, the described method is reliable and provides faster disease diagnostics than the conventional RT-PCR procedure to detect FMDV.

Staphylococcal cassette chromosome mec (SCCmec) characterization and molecular analysis for methicillin-resistant Staphylococcus aureus and novel SCCmec subtype IVg isolated from bovine milk in Korea

OBJECTIVES

To identify the staphylococcal cassette chromosome mec (SCCmec) types of methicillin-resistant Staphylococcus aureus (MRSA) isolated from bovine milk, and examine the genetic relatedness between MRSA from bovine milk and MRSA from human isolates.

METHODS

Antimicrobial susceptibility tests were performed on MRSA isolated from bovine milk. PCR and sequencing analysis were performed to determine the SCCmec type of MRSA, and to confirm their toxin carriage. Genetic relatedness among the bovine isolates and between bovine and human isolates was detected with PFGE and multilocus sequence typing (MLST).

RESULTS

Fourteen MRSA and a silent mecA-carrying methicillin-susceptible S. aureus (smMSSA) were isolated from the milk of cows with an isolation ratio of 0.18%. SCCmec of 14 MRSA strains were designated as new subtype IVg, and one smMSSA strain was not classified. All 14 MRSA strains shared Panton-Valentine leucocidin (PVL) and staphylococcal enterotoxin D (SED), SEI and SEJ; the smMSSA strain had only PVL. All MRSA and smMSSA isolates showed no multidrug resistance and had community-acquired MRSA (CA-MRSA) characteristics. PFGE revealed that all isolates except the smMSSA belonged to the same genetic lineage, and MLST analysis showed that they had no genetic relatedness with CA-MRSA which had caused human infection in Korea.

CONCLUSIONS

MRSA isolated from bovine milk harboured a unique SCCmec subtype, and they may not be correlated with the emergence of CA-MRSA in human infection in Korea.

Identification and antigenic site analysis of foot-and-mouth disease virus from pigs and cattle in Korea

From May to June 2002, a total of 16 foot-and mouth disease (FMD) outbreaks due to the serotype O virus, Pan Asia strain, were recorded in Korea. The viruses were identified by antigen ELISA, RT-PCR and sequence analysis. The overall nucleotide sequence divergence of the VP1 region among the 4 isolates in 2002 was 0 to 1.4%, but between O/SKR/2002 and O/SKR/2000 isolates was 1.9-4.9%. Phylogenetic analysis with the some known strains from East Asian countries showed that the 4 Korean isolates in 2002 formed one distinct cluster, which different from clusters of Korean isolates in 2000, with in the same lineage of the ME-SA topotype strains. Deduced amino acid sequences around neutralizable antigenic site on VP1 site of O/SKR/2002 isolates were aligned and compared with other strains. At the antigenic site 1, the replacements of the critical amino acid residues at position 144 from V to L and at position 152 from A to T were observed in O/SKR/2002 viruses. For antigenic site 2 and 4, there were not significant variations in general. At the antigenic site 3, the substitutions of amino acid residues were present at positions 54 and 56 in O/SKR/2002 isolates and an alternative residue I at position 54 are observed only at the sequence of O/SKR/AS/2002 (cow) virus. And the substitution (L-->P) of significant residue at position 144 was detected at the amino acid sequence of the O/SKR/2002 (cow) virus.

Comparison and analysis of the complete nucleotide sequence of foot-and-mouth disease viruses from animals in Korea and other PanAsia strains

During the last 3 years, foot-and-mouth disease virus serotype O, named PanAsia, caused two outbreaks in the Republic of Korea. To determine if there was an obvious genetic relationship between the virus isolated in 2002 (O/SKR/2002) and the O/SKR/2000, and to further analyze the epidemiological relationships between the PanAsia viruses and the viruses identified in Korea, the complete nucleotide sequence of the O/SKR/2002 and the O/SKR/2000 were determined by automatic cycling sequencing and primer walking. The nucleotides and the deduced amino acid (aa) sequences of the strains identified in Korea were compared with each other and also those enrolled in the GenBank database. In comparison and analysis of the viruses identified in Korea, any deletions or insertions in the specific fragment gene of both the O/SKR/2002 and O/SKR/2000 were not identified. However, comparison of the aa sequence of the identified virus in 2002 from pigs with those of other PanAsia strains revealed significant substitutions of 4 aa in the VPI region and 8 aa in the 3A region. In phylogenetic analysis based on the translated region, the identified virus in 2002 appeared to be the divergence of approximately 1% degree with other PanAsia viruses. Also, animal experiments indicated that O/SKR/2000 is not host-restricted and develop the clinical signs in the main susceptible livestock species (cattle and pigs). However, O/SKR/2002 did not develop the clinical signs in cattle and showed severe clinical signs only in pigs. These analytic data suggest that 2002 outbreaks in Korea is not re-occurred but re-introduced from nowhere.

Characterization of lymphocyte subpopulations and major histocompatibility complex haplotypes of mastitis-resistant and susceptible cows

Bovine mastitis is an infectious disease with a major economic influence on the dairy industry worldwide. Many factors such as environment, pathogen, and host affect susceptibility or resistance of an individual cow to bovine mastitis. Recently, there has been considerable interest in defining genetic and immunological markers that could be used to select for improved disease resistance. In this study we have analyzed the lymphocyte subpopulations of mastitis-resistant and susceptible cows using monoclonal antibodies specific for bovine leukocyte differentiation antigens and flow cytometry. We have also used a microarray typing technique to define the bovine leukocyte antigen (BoLA) class I and class II haplotypes associated with resistance or susceptibility to bovine mastitis. A striking finding of the present study is that susceptibility to mastitis was associated with major histocompatibility complex (MHC) haplotypes that have only a single set of DQ genes. The study also revealed that susceptible cows had CD4:CD8 ratios of less than one in both their mammary gland secretions and peripheral blood. These results raise the possibility that the number of DQ genes that a cow has and/or a cow's CD4:CD8 ratio could be used as indicators of susceptibility to bovine mastitis.

Vaccination as a control measure during the outbreak of foot-and-mouth disease in 2000 in Korea

The Republic of Korea had been free from foot-and-mouth disease (FMD) for 66 years until 15 cases were confirmed between 24 March and 15 April in 2000. The FMD virus isolated in Korea was an O Pan Asia type, which was also responsible for the recent outbreaks in Japan and the U.K. Control measures including the stamping-out of infected animals on neighbouring farms, movement restrictions and emergency vaccination were implemented. The decision to vaccinate was made because the cattle affected were showing severe FMD lesions, there was significant possibility that a large amount of virus had already been shed and conditions at the time seemed to favour wind-borne spread. Also, because the spread was limited to cattle, it was assumed that the use of vaccinations would be more effective than if pigs had been affected. All susceptible animals within 10 km radius of the infected farms were vaccinated with inactivated, double-oil emulsion vaccines. Totals of 860,700 and 661,770 animals were vaccinated during the first and second round of booster vaccinations, and were completed within five months of the first outbreak. The government decided to adopt a let-live policy so that the vaccinated animals were not slaughtered. However, they were placed under movement restrictions and had to be identified and registered. Although there were concerns about the vaccinated animals becoming carriers, extensive serological surveillance using NSP ELISA found no evidence of FMD in the remaining vaccinated population. The use of emergency vaccinations in 2000 is regarded as being a major factor in limiting the spread of FMD and containing the outbreak within a month.

Development of a foot-and-mouth disease NSP ELISA and its comparison with differential diagnostic methods

The gene encoding the nonstructural protein (NSP) of O/SKR/2000 foot-and-mouth disease virus (FMDV) was constructed to express under the polyhedron promoter of baculovirus. The expression of NSP was confirmed by indirect immunofluorescence assay (IFA) and Western blotting. The expressed NSP was applied as a diagnostic antigen for indirect-trapping ELISA (I-ELISA). An I-ELISA using monoclonal antibody (Mab) against 3A as trapping antibody was developed to differentiate infected from vaccinated cattle. The diagnostic efficiency of Mab linked I-ELISA was compared and evaluated with baculovirus expressed 3ABC I-ELISA from USDA and Mab (3A) linked E. coli expressed 3ABC I-ELISA from IZSLE through retrospective sero-surveillance. Compared with the two different I-ELISA methods, Mab (3A) linked I-ELISA using baculovirus expressed NSP showed the same level of sensitivity and specificity, indicating that this method is suitable for a differential diagnostic method in cattle.

Vascular endothelial growth factor levels in the serum and synovial fluid of patients with rheumatoid arthritis

OBJECTIVE

To determine the vascular endothelial growth factor (VEGF) concentrations in serum and synovial fluid (SF) from patients with rheumatoid arthritis (RA) and to search for relationships between VEGF levels and clinical and laboratory variables.

METHODS

We measured VEGF levels using an enzyme-linked immunosorbent assay. Serum samples were obtained from 99 RA patients, 49 osteoarthritis (OA) patients, and 80 normal controls. Paired samples of serum and SF were collected from 32 patients with RA and 15 with OA.

RESULTS

The mean serum VEGF concentration was 590.1 pg/ml for RA patients, 286.7 pg/ml for OA patients, and 265.8 pg/ml in controls. The serum VEGF concentration was significantly higher in the RA patients than in the OA patients or the controls (both p < 0.001). Furthermore, the VEGF levels in SF from RA patients were significantly higher than in SF from OA patients (p = 0.017). However, there was no correlation between VEGF levels in serum and SF from the same RA patients. The serum VEGF concentration was correlated with the ESR, serum CRP concentration, serum rheumatoid factor, number of tender and swollen joints, Modified Health Assessment Questionnaire, and patient and physician global assessments of disease activity in RA patients.

CONCLUSION

These results suggest that VEGF level is related to RA disease activity, suggesting that VEGF may play some role in the pathogenesis of RA.

Staphylococcus aureus associated with mammary glands of cows: genotyping to distinguish different strains among herds

The hypothesis that strains of Staphylococcus aureus are more likely to be unique to a herd than common to several herds was tested. Herds (n=28) from nine geographic areas of Korea, with elevated milk somatic cell counts (>500000 cells/ml) were enrolled in this study. Mammary quarter milk samples were aseptically collected from all lactating cows (n=616) with at least three functional quarters. Milk was cultured and S. aureus isolates were typed using pulse field gel electrophoresis of DNA SmaI digests. A total of 181 cows were identified as having S. aureus intramammary infections. A total of 52 different types of S. aureus were identified and 34 (65.4%) were associated with a single herd. A total of 18 types of S. aureus were found in multiple herds; 14 types were found in two herds, and four types were found in three herds. Herds with 1, 2, 3, and more than 3 types, were: four (14.3%); eight (28.6%); nine (32.1%); and seven (25.0%). The data indicate that the majority of strains were found in one herd only, and more than 90% were found in two or less herds, suggesting that strains of S. aureus are more likely to be restricted to a single herd, than found in multiple herds.

Isotypes of anti-beta2-glycoprotein I antibodies: association with thrombosis in patients with systemic lupus erythematosus

OBJECTIVE

To evaluate the association between isotypes of anti-beta2-glycoprotein I antibodies (anti-beta2-GPI) and thrombosis and to identify antiphospholipid antibodies (aPL) that are most associated with thrombosis in patients with systemic lupus erythematosus (SLE).

METHODS

IgG anticardiolipin antibody (aCL) and isotypes of anti-beta2-GPI were measured by ELISA, and clinical evidence of thrombosis was analyzed in 270 patients with SLE.

RESULTS

IgG, IgM, and IgA anti-beta2-GPI were positive in 38.1, 13.7, and 34.8% of patients, respectively. Patients with a history of thrombosis were significantly more likely to have lupus anticoagulant (LAC), IgG aCL, and the 3 anti-beta2-GPI isotypes. Arterial thrombosis was associated with the presence of IgG aCL and the 3 anti-beta2-GPI isotypes, whereas venous thrombosis was associated with LAC, IgG aCL, and IgA anti-beta2-GPI. In stepwise multivariate logistic regression analysis, the variable that was associated with thrombosis was IgA anti-beta2-GPI. The occurrence of arterial thrombosis was associated with IgG aCL and that of venous thrombosis was related to IgA anti-beta2-GPI in stepwise multivariate analysis. The IgG, IgM, and IgA anti-beta2-GPI titers were closely correlated with IgG aCL titers. The IgA anti-beta2-GPI titers were also significantly correlated with those of IgG and IgM anti-beta2-GPI.

CONCLUSION

The results suggest that anti-beta2-GPI isotypes are related to the occurrence of thrombosis, and measurements of IgA anti-beta2-GPI may be useful for predicting thrombotic episodes in patients with SLE.

Decreased trabecular bone mineral density in newly diagnosed inflammatory bowel disease patients in Korea

BACKGROUND

Decreased bone mineral density (BMD) is common in Western patients with inflammatory bowel disease (IBD). However, BMD has never been studied in Asia where the demographic and socio-economic status are different from the West. The aim of this study was to investigate the prevalence and mechanisms of osteopenia in newly diagnosed Korean patients with IBD.

METHODS

We studied 14 patients with Crohn's disease (CD) and 25 patients with ulcerative colitis (UC), all of whom had never been treated with corticosteroids. Bone mineral density was measured in the lumbar spine and the femoral neck by dual energy X-ray absorptiometry. Biochemical parameters including serum osteocalcin, parathyroid hormone, plasma inactive and active vitamin D, and urinary deoxypyridinoline were measured.

RESULTS

The BMD Z score at the lumbar spine was lower both in CD and in UC patients, but there was no significant difference between the two groups. There was no significant difference in nutritional status or biochemical parameters of bone metabolism between patients with a normal BMD and those with a decreased BMD.

CONCLUSIONS

Low BMD at the lumbar spine is common in newly diagnosed Korean patients with IBD, a result which is similar to Western studies. The mechanism for low bone mass remains undetermined; however, nutritional status and hormonal parameters of bone metabolism, and ethnic differences are not likely to be an important factor in the pathogenesis of this bone loss.

IgG antibodies to type II collagen reflect inflammatory activity in patients with rheumatoid arthritis

OBJECTIVE

To determine the clinical significance of IgG antibodies to type II collagen (CII) and to define any correlation of antibodies to CII with the inflammatory response in patients with rheumatoid arthritis (RA).

METHODS

IgG antibodies to native human type II collagen (IgG anti-CII) were measured in sera and synovial fluid (SF) from patients with RA, patients with osteoarthritis (OA), and healthy controls by an improved ELISA. Demographic, clinical, and laboratory data including tumor necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6) levels were also obtained at the time of sampling in patients with RA.

RESULTS

The median level and positivity for circulating IgG anti-CII were higher in patients with RA (n = 297) than patients with OA (n = 34) and healthy controls (n = 50) (p < 0.001). The titers of IgG anti-CII in SF were also higher in RA (n = 45) than in OA (n = 16) (p < 0.001). In paired samples, the levels of IgG anti-CII were significantly higher in SF compared to the sera in patients with RA (n = 45) (p < 0.001), but levels were not different in patients with OA (n = 16). Circulating IgG anti-CII converted from positive to negative in 13 patients (10.7%) and from negative to positive in 18 patients (14.8%) among 122 patients with RA in whom IgG anti-CII were monitored sequentially at a mean interval of 12.2 months. IgG anti-CII positive patients (n = 98) had shorter disease duration (p = 0.04) and less frequent deformity (p = 0.013), and higher median erythrocyte sedimentation rate (ESR) (p = 0.001) and C-reactive protein (CRP) (p < 0.001) than IgG anti-CII negative patients (n = 120). The levels of IgG anti-CII correlated with CRP (r = 0.270) and ESR (r = 0.253). CRP decreased significantly in patients (n = 13) who converted from IgG anti-CII positive to negative (p = 0.013). IgG anti-CII positive patients (n = 40) had higher levels of TNF-alpha and IL-6 than negative patients (n = 40) (p < 0.001). Levels of IgG anti-CII correlated well with TNF-alpha (r = 0.617) and IL-6 (r = 0.347).

CONCLUSION

Increased IgG anti-CII in sera and SF in RA correlated directly with acute phase reactants and the proinflammatory cytokines TNF-alpha and IL-6. Our data suggest that IgG anti-CII could reflect inflammatory activity with a potential to destroy cartilage in the early stages of RA.

Evidence for the expression of a second CD6 ligand by synovial fibroblasts

OBJECTIVE

CD6, a cell surface glycoprotein expressed primarily on T cells, may function as a costimulatory molecule and may play a role in autoreactive immune responses. Recently, a CD6 ligand termed CD166 (previously known as activated leukocyte cell adhesion molecule [ALCAM]) has been identified and shown to be expressed on activated T cells, B cells, thymic epithelium, keratinocytes, and in rheumatoid arthritis synovial tissue. However, the results of functional studies have suggested the existence of a second CD6 ligand. The present study was undertaken to seek evidence for a second CD6 ligand on cultured synovial fibroblasts.

METHODS

Flow cytometric and biochemical techniques were applied, using anti-CD166 monoclonal antibody (mAb) and a recombinant CD6 fusion protein, to determine whether cultured synovial fibroblasts and other cell types expressed a non-ALCAM CD6 ligand.

RESULTS

CD14- fibroblastic synoviocytes showed greater binding of a recombinant CD6 fusion protein than of anti-ALCAM mAb. With interferon-gamma treatment of synovial fibroblasts, binding of both reagents increased, but this was more marked for binding of CD6 fusion protein. Exposure of synovial fibroblasts to other cytokines or to the superantigen staphylococcal enterotoxin A also regulated binding of CD6 fusion protein and anti-ALCAM mAb in a discordant manner. Immunoprecipitation of proteins from membrane extracts of synovial fibroblasts with a CD6-Ig fusion protein revealed a novel 130-kd band distinct from CD166; an identical molecule was also precipitated from membranes of HBL-100 tumor cells.

CONCLUSION

Taken together with previous data regarding CD6 and CD166 function, the present findings strongly suggest the existence of a second CD6 ligand distinct from CD166, which can be expressed by synovial fibroblasts as well as other cells.

Divergent effect of cyclosporine on Th1/Th2 type cytokines in patients with severe, refractory rheumatoid arthritis

OBJECTIVE

To investigate the effect of cyclosporine on cytokine production, especially on T helper 1 (Th1) and T helper 2 (Th2) type cytokines, in patients with rheumatoid arthritis (RA).

METHODS

A 16 week randomized, double blind, placebo controlled study of cyclosporine (2.5 to 4 mg/kg/day) was conducted in 40 patients with severe, refractory RA who had residual inflammation and disability despite partial responses to prior maximal tolerated dose of methotrexate (MTX; < 15 mg/week) and low dose prednisone (< 10 mg/day). Clinical and laboratory variables, and circulating levels of interleukin 2 (IL-2), IL-4, IL-10, IL-12, tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) measured by ELISA were compared between patients (cyclosporine group) treated with cyclosporine plus MTX and those (placebo group) treated with placebo plus MTX at entry and at 16 weeks.

RESULTS

At 16 weeks, the cyclosporine group (n = 17), compared with the placebo group (n = 17), had greater decreases in tender joints, swollen joints, patient global assessment, patient self-assessed disability, and C-reactive protein, as well as having more patients with > 20% improvement. Comparison of circulating cytokines at entry and at 16 weeks showed significant decreases of IL-2 (median -61 vs 7 pg/ml; p = 0.004) ("+" denotes increase, "-" denotes decrease), IL-12 (median -313 vs -14 pg/ml; p = 0.002), TNF-alpha (median -55 vs 5 pg/ml; p < 0.001), and IFN-gamma (median -21 vs 5 pg/ml; p = 0.003), and a significant increase of IL-10 (median 55 vs -12 pg/ml; p < 0.001) in the cyclosporine group compared with the placebo group. The degree of IL-10 increases correlated strongly with the degree of IL-12 decreases in the cyclosporine group (r = 0.572, p = 0.016). However, there was no change in circulating IL-4 between the 2 groups. Within the cyclosporine group, the improved patients (n = 10) compared to the non-improved patients (n = 7) had a greater increase in circulating IL-10 (median 172.0 vs 85.2%; p = 0.01). The rate of increase of IL-10 strongly correlated with the rate of improvement of joint scores (r = 0.718, p = 0.001) after administration of cyclosporine.

CONCLUSION

Our results suggest that the therapeutic effect of cyclosporine is achieved by correcting a Th1/Th2 imbalance (a shift of Th1 type to Th2 type), which may be involved in the pathogenesis of RA; and that circulating IL-10 is useful to assess the clinical improvements in patients with RA after administration of cyclosporine.

Dynamic elastic constants of anisotropic materials by resonant ultrasound spectroscopy

Resonant ultrasound spectroscopy (RUS) has been applied to the anisotropic elastic stiffness determination of SiC/Al composites and highly textured Zr-2.5 Nb alloys. To determine the elastic stiffness of anisotropic materials, the resonant frequencies of a rectangular parallelepiped specimen were measured and compared with the calculated frequencies based on the input data of the estimated stiffness, dimensions, and density. The initial estimates of the elastic stiffness of SiC/Al composites were calculated using the Mori-Tananka (MT) theory and the concept of effective aspect ratio of reinforcements. For highly textured Zr-2.5 Nb alloy, the initial estimates were obtained from its orientation distribution function, determined by X-ray diffraction, and the reported elastic stiffness of a single crystal zirconium. Through a comparison of calculated frequencies with those measured by RUS, elastic stiffness values have been determined very accurately by iteration and convergence processes.