First detection of the mcr-1 colistin resistance gene in Escherichia coli from a patient with urinary tract infection in Myanmar

Colistin-resistance gene mcr-1 was detected in an Escherichia coli sample among 442 clinical isolates collected in a tertiary-care hospital in Yangon, Myanmar, in 2018. This isolate was classified into phylogroup A–ST23 complex and harboured bla_CTX-M-15 and bla_TEM-1, associated with multiple mutations in quinolone-resistance–determining regions in gyrA and parC.

New candidate virus in association with Hodgkin's disease

Epidemiologic and molecular investigations of Hodgkin's disease (HD) suggest a strong infectious association. The Epstein-Barr virus (EBV), together with its viral proteins, is expressed in Hodgkin-Reed-Sternberg (HRS) cells in the lymph nodes involved by HD. EBV is more likely to be related to childhood and older adult cases of HD and is much less frequently expressed in young adult HD patients, the group most expected to be associated with an infectious agent. In addition, the "hit and run" theory of EBV infection remains speculative and no other lymphotropic viruses studied to date seem to satisfy the quest for a new candidate virus in young adults with HD. We have recently found preliminary evidence suggesting a possible association between the measles virus (MV) and HD. This evidence is the subject of the present review.

Molecular Characterization of Begomoviruses Associated with Leafcurl Diseases of Tomato in Bangladesh, Laos, Malaysia, Myanmar, and Vietnam

Production of tomato (Lycopersicon esculentum) in Bangladesh, Malaysia, Myanmar, Vietnam, and Laos has been severely affected by yellow leaf curl disease. Tomato leaf samples were collected from symptomatic tomato plants from farmers' fields in the five countries from 1997 to 1999. DNA was extracted from all samples, four from Vietnam, two each from Malaysia, Laos, and Myanmar, and seven from Bangladesh. Virus DNA was amplified by polymerase chain reaction (PCR) using the begomovirus-specific degenerate primer pair PAL1v 1978/PAR1c 715(1), which amplifies the top part of DNA A. All samples gave the expected 1.4-kb PCR product. The PCR product of one sample per country was cloned and sequenced. Based on the sequences of the 1.4-kb DNA products amplified by the first primer pair, specific primers were designed to complete each of the DNA A sequences. Computer-assisted sequence comparisons were performed with begomovirus sequences available in the laboratory at the Asian Vegetable Research and Development Center, Shanhua, Tainan, and in the GenBank sequence database. The five DNA species resembled DNA A of begomoviruses. For the detection of DNA B two degenerate primer pairs were used, DNABLC1/DNABLV2 and DNABLC2/DNABLV2 (DNABLC1: 5'-GTVAATGGRGTDCACTTCTG-3', DNABLC2: 5'-RGTDCACTT CTGYARGATGC-3', DNABLV2: 5'-GAGTAGTAGTGBAKGTTGCA-3'), which were specifically designed to amplify DNA B of Asian tomato geminiviruses. Only the virus associated with yellow leaf curl of tomato in Bangladesh was found to contain a DNA B component, which was detected with the DNABLC1/DNABLV2 primer pair. The DNA A sequence derived from the virus associated with tomato yellow leaf curl from Myanmar (GenBank Accession No. AF206674) showed highest sequence identity (94%) with tomato yellow leaf curl virus from Thailand (GenBank Accession No. X63015), suggesting that it is a closely related strain of this virus. The other four viruses were distinct begomoviruses, because their sequences shared less than 90% identity with known begomoviruses of tomato or other crops. The sequence derived from the virus associated with tomato yellow leaf curl from Vietnam (GenBank Accession No. AF264063) showed highest sequence identity (82%) with the virus associated with chili leaf curl from Malaysia (GenBank Accession No. AF414287), whereas the virus associated with yellow leaf curl symptoms in tomato in Bangladesh (GenBank Accession No. AF188481) had the highest sequence identity (88%) with a tobacco geminivirus from Yunnan, China (GenBank Accession No. AF240675). The sequence derived from the virus associated with tomato yellow leaf curl from Laos (GenBank Accession No. AF195782) had the highest sequence identity (88%) with the tomato begomovirus from Malaysia (GenBank Accession No. AF327436). This report provides further evidence of the great genetic diversity of tomato-infecting begomoviruses in Asia. Reference: M. R. Rojas et al. Plant Dis. 77:340, 1993.

A comparative study of intervention methods (full, partial and non-integration) on late case detection and treatment irregularity in Yangon, Myanmar

The high percentage (20%) of new cases with grade 2 disabilities, and a low treatment regularity of 47% indicated problems in case detection and case holding in Urban Yangon. The fact that Urban Health Centers (UHCs) were not involved in leprosy control programme might have had an adverse influence. To compare the effectiveness of two methods of integration (full and partial) of urban leprosy services in terms of early case detection and regularity of treatment this study was conducted, in an urban area. Two townships with similar leprosy prevalence, staff infrastructure, socio-economic status, transport, communication and working capacity of the Township Medical Officers (TMOs) were chosen for this intervention study: UHC-A(Thingangyun) for full integration and UHC-B(Tamwe) for partial integration and the remaining 14 townships as non-integrated areas served by the Central Special Skin Clinic (CSSC). This study has shown that it was possible to fully integrate Leprosy Control Programme (LCP) into the Urban Health Centres [Basic Health Services (BHS)] in Urban Yangon. Case detection could be improved by active case finding such as contact examination and school examination conducted by the personnel of UHCs. Treatment regularity was found to be directly proportional to prompt defaulter retrieval action and the motivational level of the TMO and peripheral BHS workers. There were more complaints from patients (8.1%) treated at UHC-A when compared to CSSC (6.7%). Among defaulters there were more adults than children, more males than females and more PB than MB patients.

Effects of recombinant human macrophage colony-stimulating factor on proliferation, differentiation and survival of Kupffer cells in the liver of adult mice

OBJECTIVE

To investigate the effects of macrophage colony-stimulating factor (M-CSF) on the proliferation, differentiation and survival of Kupffer cells in the liver of adult mice.

STUDY DESIGN

By the combined method of autoradiography with [3H]thymidine and immunohistochemistry using a monoclonal antibody against mouse macrophages (F4/80 or BM8), the labeling rate of [3H]thymidine in macrophages within the liver sinusoids was examined at various intervals after single flash labeling with [3H]thymidine in adult mice with or without daily administration of recombinant human M-CSF.

RESULTS

A minor population of Kupffer cells (about 2%) possessed proliferative capacity under a normal steady state condition. With time after flash labeling, the influx of monocytes and their differentiation into macrophages were demonstrated in the liver, and their labeling rate returned to the baseline level one week later. Afterward, the labeling rate of Kupffer cells was maintained at the baseline level until the end of five weeks. Administration of M-CSF enhanced the proliferative capacity of Kupffer cells, increased the number of macrophages and delayed the time of peaking. However, it did not prolong the survival of Kupffer cells.

CONCLUSION

In normal mice, Kupffer cells can survive for at least five weeks. Daily M-CSF administration induces the increased number and proliferative capacity of Kupffer cells.

Granulocyte/macrophage colony-stimulating factor and interleukin-3 correct osteopetrosis in mice with osteopetrosis mutation

Although young mice homozygous for the osteopetrosis (op) mutation usually developed prominent osteopetrosis, its severity was markedly reduced in aged op/op mice. This age-associated reversal of osteopetrosis was accompanied by the expansion of bone marrow cavities and increased numbers of tartrate-resistant acid phosphatase (TRAP)-positive cells and of macrophages in the bone marrow. The TRAP-positive cells were mononuclear and developed ruffled borders and numerous vesicles, vacuoles, and granules. Enzyme-linked immunosorbent assay demonstrated a significant elevation of serum granulocyte/ macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-3 levels in the aged op/op mice. To examine whether GM-CSF and/or IL-3 could correct osteopetrosis in young op/op mice, 5 ng of recombinant murine (rm)GM-CSF and/or 100 ng of rmIL-3 were injected daily into young op/op mice. In these treated young op/op mice, the bone marrow cavities were expanded significantly at 2 weeks after administration, associated with significantly increased numbers of TRAP-positive cells and bone marrow macrophages. TRAP-positive cells increased in number with days after injection. These results suggest that GM-CSF and IL-3 induce the development of osteoclasts to correct osteopetrosis in the op/op mice with aging.

Effects of granulocyte/macrophage colony-stimulating factor on the development and differentiation of CD5-positive macrophages and their potential derivation from a CD5-positive B-cell lineage in mice

In co-cultures of either the murine pre-B cell line J13, fetal liver cells, or adult peritoneal or bone marrow cells with ST2 mouse bone marrow stromal cells in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF), the development of CD5+ macrophages was demonstrated by immunohistochemical staining and flow cytometry. Although CD5+ macrophages were not present in the peritoneal cavities of normal mice, approximately 30% of the peritoneal macrophages in viable motheaten (mev/mev) mice, deficient in SHP-1 protein tyrosine phosphatase, expressed cell surface CD5 and B220, markers for B cells. In the mev/mev mice, GM-CSF level in peritoneal fluid was increased significantly. At 5 days after daily intravenous injection with GM-CSF, many CD5+ macrophages appeared in the peritoneal cavity and in omental milky spots of normal mice but fewer in osteopetrosis (op) mutant mice, deficient in macrophage (M)-CSF. These results indicate that GM-CSF, in combination with M-CSF, induces the development and differentiation of CD5+ macrophages in the peritoneal cavity, particularly in the omental milky spots of mice. In the peritoneal cavity of GM-CSF-treated mice, the percentages of hematopoietic progenitor cells doubly positive for CD5 and CD34 or c-kit and of macrophage precursor cells doubly positive for CD5 and ER-MP58 or ER-MP20 were increased significantly during the development of CD5+ macrophages and CD5 B cells, suggesting that CD5+ macrophages and B cells may share a bipotential progenitor in vivo.