Biomedical subjects

L H Lim

Publications and source records attributed to L H Lim.

At least 19 recordsLinked to original sources

PubMed2004

High-level expression of a codon optimized recombinant dust mite allergen, Blo t 5, in Chinese hamster ovary cells.

Blo t 5 is a major allergen from house dust mite Blomia tropicalis. Purification of native Blo t 5 (nBlo t 5) from whole dust mite extract is tedious and gave low yield. In this study, we demonstrated that codon optimization facilitated high-level expression of Blo t 5 in Chinese hamster ovary (CHO)-K1 cells and thus allows production of sufficient recombinant cBlo t 5 for specific immunotherapy. A codon optimized Blo t 5 gene was synthesized by PCR and the codon optimized or wild-type Blo t 5 gene in pcDNA3.0 was transfected into CHO-K1 cells and stably selected with Geneticin (G418). Western-immunoblot analysis of spent culture media detected a positive band at 14kDa for the codon optimized but not wild-type gene transfectants. In addition, a stable CHO-K1 clone produced up to 13 mg/L of the cBlo t 5 protein having a high correlation of human IgE reactivities and allergenicity to the native Blo t 5, thus indicating proper conformation of this recombinant form.

Allergens↗

PubMed2003

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: V. Five new species of Thaparocleidus Jain, 1952 (Ancylodiscoididae) from Pangasius Nasutus.

The examination of gill parasites from Pangasius nasutus (Bleeker, 1862) (Siluriformes, Pangasiidae) revealed the presence of five new species of Monogenea, all belonging to Thaparocleidus Jain, 1952 (Monogenea, Ancylodiscoididae) as defined by Lim (1996) and Lim et al. (2001): T. serpens n. sp. T. ocrea n. sp., T. megagripus n. sp., T. citreum n. sp. and T. alatus n. sp.

Animals↗

PubMed2002

Intestinal parasitic infection among five interior communities at upper Rejang River, Sarawak, Malaysia.

Intestinal parasitic infection among five interior communities at Bakun Valley, upper Rejang River, Sarawak, Malaysia, was investigated as part of a public health impact assessment of the proposed US$ 3 billion Bakun Hydroelectric Project. Coproparasitological examination of 355 stool samples from 7 of 16 villages representing 5 of 7 tribes in the area revealed infection rate of 41%. A higher infection rate was found among the settled Kayans (56%) than the seminomadic Penans (29%). Infection rate was high (68%) among children less than 14 years old. Trichuris trichiura accounted for more than 90% of all infections; less common were Ascaris lumbricoides, hookworms and Strongyloides stercoralis. Polyparasitism was found in 8% of the individuals surveyed with dual infection due to T. trichiura and A. lumbricoides being more common than dual infection with T. trichiura and hookworm. Women had higher infection rates (57%) than men (33%).

Adolescent↗

PubMed2001

The use of lymphocyte function-associated antigen (LFA)-1-deficient mice to determine the role of LFA-1, Mac-1, and alpha4 integrin in the inflammatory response of neutrophils.

After injury or infection, neutrophils rapidly migrate from the circulation into tissues by means of an orderly progression of adhesion receptor engagements. Neutrophils have been previously considered to use selectins exclusively to roll on vessels before an adhesion step mediated by the beta2 integrins, lymphocyte function-associated antigen (LFA)-1, and Mac-1. Here we use LFA-1(-/-) mice, function blocking monoclonal antibodies, and intravital microscopy to investigate the roles of LFA-1, Mac-1, and alpha4 integrins in neutrophil recruitment in vivo. For the first time, we show that LFA-1 makes a contribution to neutrophil rolling by stabilizing the transient attachment or tethering phase of rolling. In contrast, Mac-1 does not appear to be important for either rolling or firm adhesion, but instead contributes to emigration from the vessel. Blocking Mac-1 in the presence of LFA-1 significantly reduces emigration, suggesting cooperation between these two integrins. Low levels of alpha4beta1 integrin can be detected on neutrophils from LFA-1(+/+) and (-/-) mice. These cells make use of alpha4beta1 during the rolling phase, particularly in the absence of LFA-1. Thus LFA-1 and alpha4beta1, together with the selectins, are involved in the rolling phase of neutrophil recruitment, and, in turn, affect the later stages of the transmigration event.

Animals↗

PubMed2001

Temporal trends, temperature dependence, and relative reactivity of atmospheric polycyclic aromatic hydrocarbons.

Atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations have declined appreciably between 1992 and 1997 at an urban background site in Birmingham, U.K. In contrast, no decline is evident in the city center between 1994 and 1997. Although most PAHs display statistically significant negative correlation with temperature, so does NOx, for which traffic (a nonseasonal activity) is the major source, and for which the negative correlation with temperature reflects seasonal boundary layer depth variations. When concentrations of PAHs divided by NOx were plotted against temperature, no significant relationship was detected for any PAH, except fluorene, phenanthrene, and fluoranthene. For these PAHs, the relationship was positive, suggesting volatilization from surfaces may be appreciable. For samples collected simultaneously at the city center and urban background sites, greater negative temperature-dependence was observed at the latter location. Although this may be partly due to the fact that the enhanced reactivity of PAHs at higher temperatures exerts a greater influence at sites more distant from emissions; the dichotomy in temperature-dependent behavior and temporal trends may also be due to city center concentrations being "buffered" by volatilization from surfaces to a greater extent than those at the urban background site.

Air Pollutants↗

PubMed2001

Morphological alteration of peritoneal mast cells and macrophages in the mouse peritoneal cavity during the early phases of an allergic inflammatory reaction.

We investigated the presence of mast cell granules in macrophages following an in vivo model of an allergic reaction. Injection of ovalbumin (100 microg) into the peritoneal cavity of sensitised mice produced a rapid (within 2 h) influx of neutrophils followed by a slower (after >4 h) eosinophil migration. Ovalbumin treatment induced a high incidence (approximately 50%) of mast cell degranulation compared to control phosphated-buffered saline-treated mice. The majority (approximately 90%) of peritoneal macrophages contained mast cell granules as early as 2 h post-ovalbumin, with lower values at later time-points, as determined by staining with Toluidine blue and Berberine sulphate. This was confirmed by electron microscopy which enabled us to identify the complex mast cell granule sub-structural components in macrophage phagosomes. In conclusion, we used histochemical and ultrastructural analyses to show that mast cell granules become internalised with macrophages during the early stages of an experimental allergic reaction.

Animals↗

PubMed2001

A Paedomorphic parasite associated with a neotenic amphibian host: phylogenetic evidence suggests a revised systematic position for Sphyranuridae within anuran and turtle Polystomatoineans.

The phylogenetic relationships of the families Polystomatidae and Sphyranuridae (subclass Polystomatoinea) within tetrapod monogenean parasites were investigated using partial 18S rDNA sequences. About 600 nucleotides of 11 species were sequenced, including 7 species of the most common subfamilies of Polystomatidae found in anurans and turtles, 1 species of the family Sphyranuridae parasitizing exclusively urodelans, and 3 species of the subclass Oligonchoinea infesting teleostean fishes. The phylogenetic analyses were performed using three reconstruction methods: neighbor-joining, maximum-parsimony, and maximum-likelihood. Polystomatoineans but not polystomatids were shown to be monophyletic. Within the polystomatoineans there are two clades: one includes the amphibian monogeneans (anuran polystomatids and urodelan sphyranurids) and the other includes the turtle polystomatids. Polystomatoineans may have coevolved with amphibian hosts, and an ancestral "polystome" dispersed at least 200 million years ago, either from the basal stem of lissamphibians or from an anuran ancestral stock, to freshwater turtles. Furthermore, the urodelan genus Sphyranura, initially assigned to the family Sphyranuridae on the basis of morphological and ontogenetic evidence, is clearly nested within polystomatids, suggesting that its systematic status must be revised. This supports recent findings which argue that species of the family Sphyranuridae may be paedomorphic parasites exclusively infesting neotenic mudpuppies.

Animals↗

PubMed2001

Sundapolystoma chalconotae n. g., n. sp. (Monogenea: Polystomatidae) from Rana chalconota (Schlegel) of Peninsular Malaysia.

Sundapolystoma chalconotae. n. g., n. sp. (Polystomatidae, Polystomatinae) is proposed for a new polystomatid from the urinary bladder of Rana chalconota (Schlegel) in Peninsular Malaysia. This is the first species of polystomatid to be described from the amphibians of Peninsular Malaysia and the second for the Southeast Asian region. This new genus, as exemplified by S. chalconotae, differs from other polystomatids, and in particular Parapolystoma Ozaki, 1935 (P. bulliense (Johnston, 1912) Ozaki, 1935 and P. johnstoni Pichelin, 1995), in having a tubular uterus and a single diffuse testis. P. crooki Vande Vusse, 1976 is similar to S. chalconotae in having a similar type of uterus and testis, and is re-assigned as Sundapolystoma crooki (Vande Vusse, 1976) n. comb. S. chalconotae differs from S. crooki in having anchors with a longer outer root rather than a longer inner root and 7-8 genital spines compared to 9-13 in S. crooki.

Animals↗

PubMed2001

Dactylogyridean monogeneans of the siluriform fishes of the Old World.

This is a catalogue and discussion of the known dactylogyridean monogenean genera of siluriform fishes of the Old World. Of a total of 38 nominal genera, only 19 are considered valid. Seventeen of these 19 genera are currently in the Ancyrocephalidae (containing the Ancyrocephalinae and Ancylodiscoidinae), whilst the other two (Neocalceostoma and Neocalceostomoides) are in the Neocalceostomatidae. The 17 genera are Anchylodiscus, Ancylodiscoides, Bagrobdella, Bifurcohaptor, Bychowskyella, Chauhanellus, Cornudiscoides, Hamatopeduncularia, Mizelleus, Paraquadriacanthus, Pseudancylodiscoides, Protoancylodiscoides, Quadriacanthus, Schilbetrema, Schilbetrematoides, Synodontella and Thaparocleidus. Clariotrema Long, 1981 and Neobychowskyella Ma, Wang & Li, 1983 are considered synonyms of Bychowskyella Akhmerov, 1952, Anacornuatus Dubey, Gupta & Agarwal, 1992 is considered a synonym of Quadriacanthus Paperna, 1961, Mizellebychowskia Gupta & Sachdeva, 1990 is considered a synonym of Neocalceostoma Tripathi, 1959 and Hargitrema Tripathi, 1959 is treated as a synonym of Hamatopeduncularia Yamaguti, 1953. It is proposed that the Ancylodiscoidinae be raised to family status within the order Dactylogyridea to accommodate these 17 'ancyrocephalid' genera from siluriforms, together with Malayanodiscoides and Notopterodiscoides from notopterids. A key and the diagnostic characteristics of the 19 recognised dactylogyridean genera from catfishes plus two from notopterids, together with a list of species and synonyms, are included. New combinations made in this work are Thaparocleidus avicularia (Chen, 1987) n. comb., T. calyciflorus (Chen, 1987) n. comb., T. choanovagina (Luo & Lang, 1981) n. comb., T. dissimilis (Chen, 1988) n. comb., T. leiocassis (Reichenbach-Klinke, 1959) n. comb., T. meticulosa (Chen, 1987) n. comb., T. parasoti (Zhao & Ma, 1999) n. comb., T. persculpus (Chen, 1987) n. comb., T. valga (Chen, 1987) n. comb. and T. wulingensis (Yao & Wang, 1997) n. comb. [all from Silurodiscoides] and Bychowskyella glyptothoraci (Ma, Wang & Li, 1983) n. comb. [from Neobychowskyella].

Africa↗

PubMed2001

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: I. Five new species of Thaparocleidus Jain, 1952 (Ancylodiscoidinae) from Pangasius pangasius, P. kinabatanganensis, P. rheophilus and P. nieuwenhuisii.

The examination of gill parasites from Pangasius pangasius (Hamilton, 1822); P. kinabatanganensis Roberts & Vidthayanon, 1991; P. rheophilus Pouyaud & Teugels, 2000 and P. nieuwenhuisii (Popta, 1904) (Siluriformes, Pangasiidae) in Southeast Asia revealed the presence of six species of Thaparocleidus Jain, 1952 (Monogenea, Ancylodiscoidinae). One has been previously described from P. pangasius: T. pangasi (Tripathi, 1957). The other five are new species: T. chandpuri n. sp. from P. pangasius; T. bahari n. sp. and T. sabanensis n. sp. from P. kinabatanganensis; T. redebensis n. sp. from P. rheophilus and T. mahakamensis n. sp. from P. nieuwenhuisii.

Animals↗

PubMed2001

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: II. Four new species of Thaparocleidus Jain, 1952 (Ancylodiscoidinae) from Pangasius humeralis.

The examination of gills from two rare endemic species of Pangasius Valenciennes, 1840 (Siluriformes, Pangasiidae): P. humeralis Roberts, 1989 (five specimens) and P. lithostoma Roberts, 1989 (six specimens) from the Kapuas River (West Kalimantan province, Bomeo Island, Indonesia) revealed the presence of four new species of Monogenea belonging to the genus Thaparocleidus Jain, 1952 (Monogenea, Ancylodiscoidinae) on P. humeralis: T. sinespinae n. sp., T. brevicochleus n. sp., T. kapuasensis n. sp. and T. gustianoi n. sp., and not any on P. lithostoma.

Animals↗

PubMed2001

Thyrotrophin (TSH)-secreting pituitary macroadenoma with cavernous sinus invasion.

Thyrotrophin (TSH)-secreting pituitary adenomas, although rare, should be recognised as a possible cause of normal or elevated serum TSH in the presence of elevated serum free thyroid hormone levels. Clinical hyperthyroidism may be mild or absent. Early recognition provides the best chance for surgical cure. We report a patient with a TSH-secreting pituitary tumour with cavernous sinus invasion. This case illustrates that multiple modalities of treatment are often necessary and complementary in achieving control of tumour growth and hormonal hypersecretion when these tumours are diagnosed late.

Adenoma↗

PubMed2000

Phylogenetic position of the monogeneans Sundanonchus, Thaparocleidus, and Cichlidogyrus inferred from 28S rDNA sequences.

A molecular phylogeny was inferred from newly obtained partial 28S rRNA gene sequences of Sundanonchus micropeltis (Sundanonchidae), Thaparocleidus siamensis and Cichlidogyrus sp. (Ancyrocephalidae), and other already available sequences. Although sequences are lacking for several families, the following phylogenetic relationships could be inferred. The Diplectanidae were the sister-group to a clade including Sundanonchus and the Ancyrocephalidae; Sundanonchus was the sister-group to the Ancyrocephalidae, therefore suggesting validity of the Sundanonchidae, which include this single genus; within the Ancyrocephalidae, Thaparocleidus (Ancylodiscoidinae) was the sister-group to the four other taxa, though with relatively low support, suggesting that the Ancylodiscoidinae are the sister-group to the Ancyrocephalinae.

Animals↗

PubMed2000

Malignancy of the temporal bone and external auditory canal.

A retrospective study of 18 patients with malignant tumors of the external auditory canal and temporal bone was undertaken to gain an Asian perspective of this rare disease. Of these patients, 15 (83%) had squamous cell carcinoma (SCC) and 61% had stage T3 tumors at presentation. The mean age was 56 years (range 38-82 years). Seven (39%) of the 18 patients had radiation-associated tumors (RATs), and all had undergone radiotherapy for treatment of nasopharyngeal carcinoma. The 1-year cumulative recurrence for the RAT group was 100%, but there was no recurrence in the non-RAT group (P = 0.001). In malignancies of the external auditory canal and temporal bone, a different classification and staging system for patients with RATs may be warranted to better guide treatment strategies.

Adult↗

PubMed2000

Glucocorticoid receptor activation reduces CD11b and CD49d levels on murine eosinophils: characterization and functional relevance.

In vitro incubation of mouse blood eosinophils with dexamethasone (DEX) resulted in concentration- and time-dependent reduction in CD11b and CD49d cell-surface expression as detected by flow cytometry. This inhibitory effect ranged between 20 and 40% for both integrins, and it was not related to alteration of cell survival. DEX was maximally effective at 1 microM, and it was prevented by coaddition of the glucocorticoid receptor antagonist RU486 (mifepristone; 10 microM). Budesonide, hydrocortisone, and prednisolone, but not the sex steroids testosterone and progesterone, reduced CD11b and CD49d cell-surface expression to a similar extent. Subchronic treatment of mice with 1 mg/kg DEX again reduced both CD11b and CD49d expression on circulating eosinophils, without alterations in CD11b messenger RNA expression as assessed by polymerase chain reaction analysis. In contrast, membrane but not intracellular protein expression of either CD11b or CD49d was inhibited by eosinophil incubation with DEX in vitro; thus, an interference with exportation of these adhesion molecules to the cell surface is proposed as the mechanism of action of the glucocorticoid. Finally, steroid effects on integrin expression were linked to a reduced eosinophil function as indicated by a lower degree of cell chemotaxis after incubation with DEX, an effect which was again prevented by 10 microM RU486. These observations may explain part of the therapeutic efficacy displayed by glucocorticoid hormones in the clinical control of tissue eosinophilia in allergic disease conditions.

Animals↗

PubMed2000

Neopolystoma liewi sp. n. (Monogenea: Polystomatidae) from the eye of the Malayan box turtle (Cuora amboinensis).

Neopolystoma liewi sp. n. is described from the conjunctival cavity of the Malayan box turtle Cuora amboinensis (Daudin, 1802), in Peninsular Malaysia. This is the first record of Neopolystoma in Malaysia and the fourth polystomatid species described from C. amboinensis. Of the 27 Malayan box turtles examined, 8 were found to be infected. A maximum of 2 parasites per eye and 4 individuals per host was recorded. N. liewi sp. n. differs from all other members of the genus by possessing few and short genital spines and small marginal hooks. The oncomiracidium has 64 ciliated cells arranged symmetrically about the sagittal axis.

Animals↗

PubMed1998

Promoting detachment of neutrophils adherent to murine postcapillary venules to control inflammation: effect of lipocortin 1.

In this study we investigated, using intravital microscopy, how neutrophil extravasation across mouse mesenteric postcapillary venules is inhibited by the glucocorticoid-regulated protein lipocortin (LC; also termed annexin) 1. Intraperitoneal injection of 1 mg of zymosan into mice induced neutrophil rolling on the activated mesenteric endothelium followed by adhesion (maximal at 2 hr: 5-6 cells per 100-micrometers of vessel length) and emigration (maximal at 4 hr: 8-10 cells per high-powered field). Treatment of mice with human recombinant LC1 (2 mg/kg s.c.) or its mimetic peptide Ac2-26 (13 mg/kg s.c.) did not modify cell rolling but markedly reduced (>/=50%) the degree of neutrophil adhesion and emigration (P < 0.05). Intravenous treatment with peptide Ac2-26 (13 mg/kg) or recombinant human LC1 (0.7-2 mg/kg) promoted detachment of neutrophils adherent to the endothelium 2 hr after zymosan administration, with adherent cells detaching within 4.12 +/- 0.75 min and 2.36 +/- 0.31 min, respectively (n = 20-25 cells). Recruitment of newly adherent cells to the endothelium was unaffected. The structurally related protein LC5 was inactive in this assay, whereas a chimeric molecule constructed from the N terminus of LC1 (49 aa) attached to the core region of LC5 produced cell detachment with kinetics similar to LC1. Removal of adherent neutrophils from activated postcapillary endothelium is a novel pharmacological action, and it is at this site where LC1 and its mimetics operate to down-regulate this aspect of the host inflammatory response.

Amino Acid Sequence↗

PubMed1998

Diversity of monogeneans in Southeast Asia.

The diversity of monogeneans from Southeast Asia was examined using information from the literature to show their diversity at different taxonomic (subclass, family, genera, species) levels. Knowledge of monogeneans is still incomplete in Southeast Asia and the present numbers of monogeneans are likely an underestimate of what is present on/in aquatic organisms in the region, since so few hosts have been examined. An estimate of the possible numbers of monogeneans that could be present on/in fishes and turtles in Peninsular Malaysia indicates that only 8% of the monogeneans are presently known. Analysis of the available data on monogenean diversity (or species richness) at different taxonomic levels will provide useful information on their distribution patterns. There is an uneven distribution of investigations on this topic and Malayan fauna is considered to be representative of the Southeast Asian fauna. Southeast Asian (Sundaland) monogeneans are related (at the generic level) to the monogenean fauna of South China, India and Africa.

Amphibians↗