Background: Human Respiratory Syncytial Virus (HRSV) is a major viral pathogen associated with acute lower respiratory tract infections (ALRTI) in children. Using monoclonal antibodies against virus proteins, it is categorized into two distinct major groups, A and B. The second hypervariable region of the G protein ectodomain gene provides a reliable surrogate for phylogenetical studies. We carried out a phylogenetic analysis of the HRSV strains isolated from children hospitalized with ALRTI in Malaysia.Methods: Nasopharyngeal aspirates (NPA) were taken from children less than five years of age hospitalized with ALRTI to Hospital Serdang, Malaysia. RT-PCR was used to detect HRSV. The second hypervariable region at the carboxyl-terminal of the G gene was amplified and sequenced using primer sets GPA/F1 and GPB/F1. Neucleotide sequences were edited and aligned with Bioedite software and Clustal X program. The phylogenetic relationships of the samples were determined separately for group A and B using neighbor joining (NJ), maximum parsimony (MP) and Bayesian methods (BI).Results: HRSV was detected in 83 of 165 (50.3%) patients studied. Sequence analysis of 32 isolates showed that multiple lineages of HRSV group A and B serotypes co-circulated. The topologies resulting from the different methods (NJ, MP and BI) congruent with each other. Phylogenetic analysis of nine retrieved sequences showed that all the HRSV-A strains were clustered into the NA1 genotype. All the 23 HRSV-B strains belonged to BA genotypes consisted of a 60-nucleotide duplication region. They were classified into three different genotypes of BA10, BA9 and BA4, respectively.Conclusion: HRSV played a prominent role for hospitalization of children in our study. The sequences of the second hypervariable region of G protein ectodomain gene from HRSV A and B demonstrated remarkable genetic diversity. The present finding seems to be consistent with other studies which found the newly emerged HRSV genotypes of NA1 and BA genotypes are replacing the previously dominant genotypes. This is the first documentation of the phylogenetic relationship and genetic diversity of HRSV isolates among hospitalized children diagnosed with ALRTI in Malaysia.

The spectrum of protein tyrosine phosphatases (PTPs) expressed in bone marrow-derived murine macrophages (BMMs) was examined using reverse transcriptase-polymerase chain reaction. Ten different PTP cDNAs were isolated and in this study we focus on mDEP-1, a type III receptor PTP. Three mDEP-1 transcripts were expressed in primary macrophages and macrophage cell lines and were induced during macrophage differentiation of M1 myeloid leukemia cells. A variant mRNA was identified that encodes an alternate carboxylterminus and 3Ј UTR. The expression of mDEP-1 was down-regulated by CSF-1 (macrophage colonystimulating factor) and up-regulated by bacterial lipopolysaccharide, an important physiological regulator of macrophage function that opposes CSF-1 action. Whole mount in situ hybridization, and immunolocalization of the protein, confirmed that mDEP-1 is expressed by a subset of embryonic macrophages in the liver and mesenchyme. mDEP-1 was also detected in the eye and peripheral nervous system of the developing embryo. Attempts to express mDEP-1 constitutively in the macrophage cell line RAW264 were unsuccessful, with results suggesting that the gene product inhibits cell proliferation. J. Leukoc. Biol. 64: 692-701; 1998.

The gastrointestinal tracts of 76 free-living alpine marmots ( Marmota marmota) shot during a population control program in Switzerland were collected and analysed for patterns of change in morphology and function over the period from emergence from hibernation in April to just before re-entry into hibernation in September. Between first emergence and mid-summer (July) the fresh tissue mass of the stomach increased by 105%, the small intestine by 259% (among the largest recorded for a mammal), caecum by 185%, proximal colon by 138%, and distal colon by 144%. Mitotic activity was greatest in the small intestine; the mitotic index was high (40%) compared with indexes in the stomach and hindgut (approximately 4%) even at emergence, and increased to approximately 60% by mid-summer. Microbial activity in the caecum was also significant at emergence. The stomach (length) and caecum (length and fresh mass) increased in response to ingested food earlier than did the small intestine. Between mid-summer and September there were decreases in small intestinal tissue mass and mitotic activity. It is concluded that the gastrointestinal tract of alpine marmots probably continues to function throughout hibernation at a low level, with a mid-winter trough as part of an endogenous circannual rhythm. However, after emergence in spring, increases in size and activity of the tract appear to be a response to ingested food rather than to an endogenous signal. The early signs of down-regulation of the small intestine before re-entry into hibernation, together with its delayed up-regulation in response to food in spring, are consistent with the high costs of maintaining this section of the digestive system.

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Many bacterial pathogens including Salmonella and Listeria replicate within macrophages. The susceptibility of these organisms to various antibiotics is dependent on the ability of macrophages to take up, retain, and deliver the antibiotic to the correct intracellular compartment. In this context, macrophages are known to express proteins that are involved in efflux of antibiotics and cytotoxic drugs, thereby reducing intracellular accumulation of such compounds. In our studies on the action of bacterial lipopolysaccharide (LPS) on the macrophage-like cell line, RAW264 we found that LPS treatment of these cells conferred resistance to the neomycin-related aminoglycoside G418 (geneticin). This phenotype was stable and was specific to LPS since colony-stimulating factor 1 and phorbol myristate acetate had no effect on G418 resistance. We have extended this observation to show that LPS induces transient resistance to the cytotoxic drugs taxol and doxorubicin. Macrophage resistance to cytotoxic drugs and antibiotics may have a number of important clinical consequences.