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In this study, a commercial Salmonella covalent mix-enzyme linked immunosorbent assay (ELISA) for serological detection of Salmonella infection in swine was evaluated by comparing it with the conventional fecal culture method and inter-laboratory proficiency testing, using a panel of sera tested in 5 laboratories from Europe and North America. Comparison with culture results showed that 88.5% of 26 culture-positive animals were ELISA positive, as were 55% of 60 animals from 2 culture-positive pig herds. Of 90 animals from 2 high health farms with no clinical symptoms of salmonellosis, 98.9% tested negative. The interlaboratory comparison study found a kappa value of 0.9 between our laboratory (using an automated system) and the manufacturer laboratory (using the manual method). Comparison of ELISA results from all 5 participating laboratories showed very good to excellent agreement, between 85% and 97.5%. We found this assay to be useful for the screening of antibodies against Salmonella present in swine serum. It agrees well with bacterial cultures, is reproducible, sensitive, specific, repeatable, and suitable for automation.

This is a validation study of 2 commercially available enzyme linked immunosorbent assays (ELISA) for the detection of antibodies against Neospora caninum in bovine serum. The results of the reference sera (n = 30) and field sera from an infected beef herd (n = 150) were tested by both ELISAs and the results were compared statistically. When the immunoblotting results of the reference bovine sera were compared to the ELISA results, the same identity score (96.67%) and kappa values (K) (0.93) were obtained for both ELISAs. The sensitivity and specificity values for the IDEXX test were 100% and 93.33% respectively. For the Biovet test 93.33% and 100% were obtained. The corresponding positive (PV+) and negative predictive (PV-) values for the 2 assays were 93.75% and 100% (IDEXX), and 100% and 93.75% (Biovet). In the 2nd study, competitive inhibition ELISA (c-ELISA) results on bovine sera from an infected herd were compared to the 2 sets of ELISA results. The identity scores of the 2 ELISAs were 98% (IDEXX) and 97.33% (Biovet). The K values calculated were 0.96 (IDEXX) and 0.95 (Biovet). For the IDEXX test the sensitivity and specificity were 97.56% and 98.53%, whereas for the Biovet assay 95.12% and 100% were recorded, respectively. The corresponding PV+ and PV- values were 98.77% and 97.1% (IDEXX), and 100% and 94.44% (Biovet). Our validation results showed that the 2 ELISAs worked equally well and there was no statistically significant difference between the performance of the 2 tests. Both tests showed high reproducibility, repeatability and substantial agreement with results from 2 other laboratories. A quality assurance based on the requirement of the ISO/IEC 17025 standards has been adopted throughout this project for test validation procedures.

Background and Objectives: The para-Bombay phenotype (also known as H-deficient secretor) is characterized by a lack of ABH antigens on red cells, but ABH substances are found in saliva. Molecular genetic analysis was performed for five Chinese individuals serologically typed as para-Bombay., Materials and Methods: ABO genotyping and mutational analysis of both FUT1 (or H) and FUT2 (or Se) loci were performed for these individuals using the polymerase chain reaction, single-strand conformation polymorphism analysis and direct DNA sequencing., Results: The ABO genotypes of these para-Bombay individuals correlated with the types of ABH substances found in the saliva. Their FUT1 genotypes were h1h2 (three individuals), h2h2 (one individual) and h2h6 (one individual). Alleles h1 (547-552delAG) and h2 (880-882delTT) were known frameshift mutations, while h6 (522C > A) was a missense mutation (Phe174Leu) not previously reported. These three mutations were rare sequence variations, each with an allele frequency of less than 0.005. Phe174 might be functionally important because this residue is conserved from mouse to human. Their FUT2 genotypes were Se357se357,385 for the h2h6 individual and Se357Se357) for the others. Both FUT2 alleles were known: one functional (Se357) and one weakly functional (se357,385). That they carried at least one copy of a functional FUT2 allele was consistent with their secretor status. As FUT1 and FUT2 are adjacent on 19q13.3, there are three possible haplotypes in these para-Bombay individuals: h1-Se357; h2-Se357; and h6-se357,385., Conclusions: A novel non-functional FUT1 allele (522C > A, or Phe174Leu) was identified in a para-Bombay individual and on a se357,385 haplotype background.

This study examines the long-term impact of a Neospora caninum-associated abortion outbreak in a large cow-calf herd in northern Alberta. Blood samples were collected 4 times from all bred females and heifer calves born during the spring before the outbreak: (1) at the time of the outbreak, (2) the following spring, (3) the subsequent fall, and, finally, (4) the second spring after the outbreak. The samples were analyzed using a commercially available enzyme-linked immunosorbent assay for N. caninum. Calves born immediately following the outbreak were also monitored. Individual calving or abortion records were available from all cows for 2 calving seasons. All cows and heifers were pregnancy tested after the 2 subsequent breeding seasons. At the time of the abortion outbreak in 1997, 81% of all bred females and 87% of the heifer calves were serologically positive. In spring 1998, 49% of the cows and 47% of the heifer calves remained positive. In fall 1998, 48% of the remaining cows and heifers were serologically positive. After the first breeding season following the outbreak (1998), 13.5% of the heifers and 22.2% of the cows were open (not pregnant). Animals that were serologically positive in the spring were more likely to be open in the fall (odds ratio, 2.0; 95% confidence interval, 1.1 to 3.7). No subsequent associations with increased risk of abortion, stillbirth, or nonpregnancy were identified.

Blood samples were collected from 1806 pregnancy-tested cows from 174 herds at a northern Alberta auction mart in the fall of 1998. One hundred sixty-two (9.0%) of these samples were positive for antibodies to N. caninum. Thirty-five of 260 samples (13.5%) collected from the same region in the 1980s were also serologically positive for N. caninum.

We report a case of beta-thalassemia intermedia caused by compound heterozygosity for hemoglobin (Hb) Malay and codon 41/42 (-CTTT) beta(0)-thalassemia mutation in a 38-year-old Chinese woman. This patient has long-standing anemia with a baseline Hb level of around 70 g/L. She worked as a full-time cashier and had not required regular blood transfusions. Nevertheless, she had splenomegaly necessitating splenectomy, cholelithiasis, and iron overload. This case illustrates the varied phenotypic expression associated with compound heterozygosity for Hb Malay and other beta-thalassemia mutations. Since Hb Malay migrates as Hb A on electrophoresis and chromatography, this variant Hb mutation ought to be included in the differential diagnosis for beta-thalassemia major or intermedia patients of Southeast Asian descent who are reported to have Hb A on the basis of Hb analysis. The possible presence of this mutation should also be considered in appropriate cases for genetic counseling in couples at risk of conceiving fetuses with beta-thalassemia major or intermedia., (Copyright 2000 Wiley-Liss, Inc.)

The requirements of pretransfusion testing have undergone repeated modification, and those of the type and screen policy are currently the most widely accepted to be standard. The type and screen test policy, together with the abbreviated crossmatch procedure, was implemented in the United Christian Hospital in January 1997. This paper discusses the impact of the type and screen test policy on clinicians and patients, on the blood bank and hospital, and on the future of the hospital transfusion services.

A case of chronic eosinophilic leukemia (CEL) manifesting as spinal cord compression by an extradural eosinophilic chloroma in a 32-year-old Chinese man was presented, who subsequently developed extramedullary transformation at the skin and then peritoneal cavity. Cytogenetic study of bone marrow cells at diagnosis showed a clonal karyotypic abnormality of trisomy 8 (+8), which on fluorescence in situ hybridization (FISH) was shown to be present in a clone of abnormal eosinophils, hence showing the neoplastic nature of the eosinophilic proliferation. There was another population of abnormal eosinophils that did not show +8. At blastic transformation, all blast cells in ascitic fluid were shown by FISH to harbor +8. These findings suggest that +8 in this case may have arisen from clonal evolution and is not the primary genetic event in leukemogenesis, but +8 most probably imparts a further survival advantage to the clone responsible for subsequent blastic transformation.

SJL mice are an inbred strain with a high incidence of spontaneous lymphomas of the B-cell type. We used molecular markers of clonality to study the process of tumor progression of SJL lymphomas in vivo. This was accomplished at time intervals ranging from 2 to 116 days by initial partial splenectomy (biopsy) followed by spleen sampling at the time of killing (autopsy). Immunoglobulin heavy chain (IgH) gene rearrangement and murine leukemia virus (MuLV) proviral integration patterns were used to study the clonal identities of the sequential tumor pairs in 11 informative mice by Southern blot hybridization. Of these 11 mice, 5 showed the same number of IgH gene rearrangement bands in the matched biopsy-autopsy samples, indicating the persistence of the original lesions. In 2 of 11 mice, a decrease in the number of IgH gene rearrangement bands was seen, consistent with a process of clonal selection in the original oligoclonal population. Another 2 of 11 mice showed an increase in the IgH gene rearrangement bands, indicating the emergence of either a new unrelated clone or, less likely, a subclone with secondary IgH gene rearrangement. The remaining two mice showed differences between the patterns in biopsy and autopsy samples, as assessed by IgH gene rearrangement and the proviral integration analysis. This finding suggests that the biopsied tumor had regressed and new clones had emerged. Tumor development was also associated with an increase in the number of clonal MuLV insertions in all mice except one, in which no non-germline integration band was detected. Of 11 mice, 5 showed an increase in the extent of tumor involvement by microscopic examination of the biopsy and autopsy samples; 3 showed a decrease, whereas 2 showed no change. A change in tumor morphology toward a more dedifferentiated appearance was found in only 1 of 11 mice. Overall, the results did not show a single paradigm that tumor progression followed, rather they indicated a complex and dynamic process of clonal evolution, which is likely to be a major feature of lymphoma progression in vivo.

We report the incidence of the chronic lymphoproliferative disorders evolving with leukaemia in Hong Kong. Our findings demonstrate that B cell malignancies are significantly more frequent than mature T cell neoplasms, a picture similar to that seen in Western countries but different from other Eastern countries, eg Japan, where T cell malignancies are more frequent. In contrast to the West, where chronic lymphocytic leukaemia (CLL) is the most common disorder, in Hong Kong there is a clear predominance of B cell lymphomas in leukaemic phase accounting for two-thirds of the cases and particularly those displaying lymphoplasmacytic features or with villous lymphocytes. CLL in Hong Kong has similar clinical and laboratory features to the disease in patients from the West. Distinct disease categories, rare in the West such as the variant form of hairy cell leukaemia and T cell prolymphocytic leukaemia, are also documented. It is unclear whether the differences in prevalence of disease subtypes between Hong Kong and the West relate to different genetic background or environmental factors determinant of the development or progression of the leukaemia. Further studies investigating the genetic/molecular lesions may help to clarify whether the aetiopathogenesis of the lymphoid disorders in Hong Kong is similar to that of Western countries.

Robertsonian translocations, although relatively common as a constitutional genetic aberration, are rarely encountered in leukaemia. We report a case of acute myeloid leukaemia which showed an acquired Robertsonian translocation in the form of der(14;21) by cytogenetic analysis of leukaemic cells. This was confirmed by the PHA-stimulated culture of peripheral blood lymphocytes. A review of the literature identifies only eight reported cases of acquired Robertsonian translocations in leukaemia. In the majority of cases the Robertsonian translocation occurs as a secondary change in a complex abnormal clone, whereas in two out of nine patients reported, including ours, it is found as a sole karyotypic abnormality.

The CELL-DYN 3500 (CD3500) (Abbott Diagnostics Division, Santa Clara, CA, USA) is a multiparameter, automated haematology analyser system capable of producing 22 haematological parameters including a screening five-part differential. The evaluation was performed in a recently expanded acute care general hospital. Studies of linearity, carryover and precision were acceptable and within manufacturer's stated limits. Correlation of CD3500 with manual differential counts were good except for the basophil count. The white cell flagging system had a sensitivity of 83.6% and specificity of 88.9% with 85.6% agreement. The platelet flagging system also had comparable sensitivity and specificity rate of 88.4% and 94.5% and agreement rate of 92.2%. The overall false positive rate and false negative rate for both the white cell and platelet flags combined were 8.6% and 10.3%. All samples provided a differential with no rejection experienced. The MAPSS technology, together with the extended lyse mode and the investigational nine-part differential provides potential for future development in WBC differential.

We report our experience of 4 successful pregnancies (including a pair of twins) in 3 women who have essential thrombocythemia (ET). All of the patients had a significant fall in platelet count (> 20% of non-pregnant state) during the course of the pregnancy. A review of the literature and our own experience suggests that the degree of platelet count reduction may be correlated with pregnancy outcome. Close monitoring of the platelet count is useful in the management of these cases.

Forty-four SJL mice were killed at intervals to follow the spontaneous development of lymphomas. These were detected in 28 of 38 mice aged 24 weeks or more. Immunoperoxidase stains were applied on cryostat sections of lymphomas from various sites (spleen, mesenteric lymph nodes, Peyer's patches, and other lymph nodes), sampled from 19 mice of different age groups, to study tumour immunophenotype in correlation with histological features. With a panel of antibodies against Thy 1.2, Lyt 1, and Lyt 2, and the mouse immunoglobulin heavy and light chains, all the 19 tumours were shown to be B-cell derived. This was further supported by the detection of Ia antigens on the tumour cells. Six mice had plasmacytoid or predominantly plasmacytoid tumours expressing gamma kappa. Three mice had mixed plasmacytoid and pleomorphic tumours which also showed gamma kappa positivity. The ages of these nine mice ranged from 24 to 44 weeks with a median of 36 weeks. Pleomorphic tumours were found in ten mice (age range = 36-52 weeks, median = 44 weeks). These tumours were more heterogeneous, expressing either alpha, mu, or gamma, or with loss of heavy chain expression altogether. These age-related changes are probably a sign of progressive loss of differentiation in B lymphomas.