Displaying publications 861 - 880 of 1650 in total

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  1. Fulltext In vitro culture of Toxoplasma gondii
    Suresh K, Mak JW, Yong HS
    Southeast Asian J Trop Med Public Health, 1991 Sep;22(3):449-51.
    PMID: 1818400
    Matched MeSH terms: Toxoplasma/growth & development*
  2. Long term maintenance of Toxoplasma gondii (Rh strain) in Vero cell line and use of harvested antigens for immunodiagnosis
    Suresh K, Mak JW, Yong HS
    Southeast Asian J Trop Med Public Health, 1991 Dec;22 Suppl:124-8.
    PMID: 1822869
    Thirty in vitro serial passages of Toxoplasman gondii cultures in Vero cell line performed once in every five days had a mean increase in parasite count of 74.4 +/- 14.8 times from that of initial counts. Long term cultures in Vero cell line did not alter the virulence of the parasite. The good correlation (r = 0.99) between the IFA titer and ELISA OD values using the parasite antigens from in vitro sources indicates that long term maintenance of T. gondii in culture does not affect significantly the ability to recognize antibodies to surface and soluble antigens. The results also show that soluble antigens containing host cells can be directly used for immunodiagnostic purposes without purification. The in vitro maintenance of T. gondii is safer and cheaper when compared to the in vivo method.
    Matched MeSH terms: Toxoplasma/growth & development*
  3. Analysis of activator treatment changes
    Hashim HA
    Aust Orthod J, 1991 Oct;12(2):100-4.
    PMID: 1843791
    The effects of functional appliance treatment have been reported in numerous studies in the literature with great variability in the findings. It is generally agreed that they can be used successfully to treat Class II malocclusions in growing and cooperative patients. However, there is a lack of consensus regarding the relative orthodontic and orthopedic correction obtained by functional appliances in Class II correction. Lateral cephalometric radiographs from a sample (n = 36) of patients who had undergone a phase of treatment with activator appliances were measured and analysed for changes using a modified version of the method described by Johnston (Hashim and Godfrey 1990). In this method, the treatment changes were broken down into: tooth movement relative to basal bone; and the translatory growth of the jaws, both with respect to the cranial base and to each other. The results show that the treatment effects were mainly dentoalveolar. There was a slight orthopedic effect on the maxilla, but no significant mandibular growth was observed, above that which can be expected from normal growth.
    Matched MeSH terms: Mandible/growth & development
  4. Significance of enteric gram-negative bacilli in the throat
    Philpot CR, McDonald PJ, Chai KH
    J Hyg (Lond), 1980 Oct;85(2):205-10.
    PMID: 7005325
    Pharyngeal micro-organisms of 131 Australian and Malaysian children and adults were compared by analysis of aerobic culture of throat swab specimens. Enteric Gram-negative bacilli were commonly isolated in small numbers from Malaysian adults whether they had sore throats (28%) or not (36%), but were detected in only 9% of Australian adults without sore throats and in only 12% and 4% of Malaysian children with and without sore throats respectively. In other respects microbiological findings were similar in the different groups of subjects studied. It is concluded that the pharyngeal carriage rate of enteric Gram-negative bacilli may differ substantially between different groups of normal individuals. Our findings also suggest that these micro-organisms do not have a pathogenic role in pharyngitis.
    Matched MeSH terms: Escherichia coli/growth & development
  5. Fermentation of a Malaysian Bacillus thuringiensis serotype H-14 isolate, a mosquito microbial control agent utilizing local wastes
    Lee HL, Seleena P
    Southeast Asian J Trop Med Public Health, 1991 Mar;22(1):108-12.
    PMID: 1948250
    A screening program searching for indigenous microbial control agents of mosquitos in Malaysia is initiated since 1987 and to date at least 20 isolates of mosquitocidal Bacillus thuringiensis serotypes have been obtained. Preliminary field evaluation of several isolates indicated that they are highly effective in the control of medically important mosquito species. For operational purposes, there is an urgent need to produce this agent utilizing cheap and locally available wastes through fermentation biotechnology. Fermentation studies in shake-flasks containing standard nutrient broth and soya bean waste, respectively, indicate that it takes about 37 hours for a Malaysian isolate of B. thuringiensis serotype H-14 to mature. In the grated coconut waste, fishmeal and rice bran, the bacteria took 28 hours, 26 hours and 126 hours respectively to mature. The endotoxin was harvested from the standard nutrient broth at 55 hours and at 50 hours from soybean, grated coconut waste and fishmeal. The endotoxin could only be harvested 150 hours after inoculation from rice bran medium. However, no bacterial growth was detected in palm oil effluent. In terms of endotoxin and biomass production, fishmeal appears to be a suitable medium. Variations in the pH of the fermenting media were also noted.
    Matched MeSH terms: Bacillus thuringiensis/growth & development*
  6. Microbiological and pathological evaluation of vaccination against naturally occurring caprine pasteurellosis
    Zamri-Saad M, Sharif H, Basri K
    Vet Rec, 1989 Feb 18;124(7):171-2.
    PMID: 2922914
    Matched MeSH terms: Pasteurella/growth & development
  7. Hepatitis A virus in primates outside captivity
    Lancet, 1981 Oct 24;2(8252):928-9.
    PMID: 6117705
    Matched MeSH terms: Hepatovirus/growth & development*
  8. Attenuation of virulence of flaviviruses following passage in HeLa cells
    Dunster LM, Gibson CA, Stephenson JR, Minor PD, Barrett AD
    J Gen Virol, 1990 Mar;71 ( Pt 3):601-7.
    PMID: 2155996
    The ability of passage in HeLa cells to attenuate flaviviruses was investigated for three different strains of the mosquito-borne West Nile (WN) virus and two tick-borne viruses, louping-ill and Langat. One strain of WN virus, Sarawak, was attenuated 4000-fold for adult mice by intraperitoneal or intranasal challenge after six HeLa passages. The HeLa-passaged virus was also found to be antigenically different and temperature-sensitive in its growth characteristics compared with the parent. After six HeLa cell passages the Egypt 101 and Smithburn strains of WN virus lost their ability to infect monkey kidney cells and no longer killed adult mice, although inoculated animals became sick for several days. In contrast, two tick-borne flaviviruses remained as virulent for mice after six HeLa passages as the parent non-HeLa-passaged virus. Neither of the tick-borne viruses exhibited characteristics associated with temperature sensitivity. The results, therefore, indicate that the mosquito-borne, but not tick-borne, flaviviruses can be attenuated by very few passages in HeLa cells. This observation may provide a model system with which to analyse the molecular basis of attenuation and/or virulence of mosquito-borne flaviviruses.
    Matched MeSH terms: Flavivirus/growth & development
  9. Skin-piercing blood-sucking moths II: Studies on a further 3 adult Calyptra [Calpe] sp. (Lepid., Noctuidae)
    Bänziger H
    Acta Trop, 1979 Mar;36(1):23-37.
    PMID: 35931
    1. Of the scarce Calyptra minuticornis, C. orthograpta and C. labilis, 51, 24, and 7 adults, respectively, were observed during some 600 night inspections at over 100 sites in 1965--1967 and 1971--1977. 2. Hitherto biologically completely unknown, and not recorded before in S.E. Asia, the latter two species flew in or near tropical monsoon forests in hilly regions (300--600 m) of N. Thailand (C. orthograpta also N. Laos). C. minuticornis was found in these and in tropical evergreen and semi-evergreen rain forests of S. Thailand and N.W. Malaysia. 3. In N. Thailand the three species were more common at the end of the cool season/start of the hot season and at the start of the rainy season. They were active mainly during the first half of the night 4. Flight and piercing behaviour, alighting, resting, enemies, and the lack of females, were similar to virtually identical with the "classical" skin-piercing blood-sucking C. eustrigata. 5. C. labilis was seen attacking elephant, C. orthograpta also water buffalo and sambar, C. minuticornis also zebu and tapir but not sambar. C. minuticornis settled on man also but did not pierce. 6. Through no piercing of hosts' skin has actually been seen in nature, indirect evidence suggests that the 3 moths are likely to be occasional blood-suckers. They pierced and sucked blood from the author's skin in experiments. 7. Reasons for lack of direct evidence may be: less developed hematophagy, less favoured hosts, lack of easy-to-pierce injured skin (which also trigger the piercing response), different climatic and phytoecological environment, fewer specimens than in the case of C. eustrigata. 8. Field observations and experiments indicate that the closely related, fruit-piercing Oraesia emarginata is not skin-piercing blood-sucking--a habit likely to be exhibited mainly in humid equatorial regions by a few Calyptra only.
    Matched MeSH terms: Moths/growth & development
  10. Morphology of three polycentric rumen fungi and description of a procedure for the induction of zoosporogenesis and release of zoospores in cultures
    Ho YW, Bauchop T
    J. Gen. Microbiol., 1991 Jan;137(1):213-7.
    PMID: 2045780
    Three polycentric rumen fungi, LL, LC2 and Ruminomyces elegans (C2), isolated from the rumen of cattle were grown in six culture media. LL and LC2 were morphologically similar. Their characteristics resembled those of Orpinomyces and Neocallimastix joyonii, and they grew well and produced sporangia after 3-4 d growth in all the media. R. elegans differed morphologically from LL and LC2, but although it also grew well in all media, abundant sporangia occurred only after 2-3 d growth in media containing cellulose. Undifferentiated sporangia were produced by all three isolates; differentiation of the sporangia did not occur in the spent growth media. However, if thalli possessing recently-formed sporangia were transferred to, or flooded with, fresh liquid medium or rumen fluid, zoosporogenesis and liberation of zoospores occurred within 17-20 min for isolates LL and LC2 and 30 min for R. elegans. Procedures for inducing zoosporogenesis by polycentric anaerobic fungi are described.
    Matched MeSH terms: Fungi/growth & development
  11. Studies on the chemoprophylaxis of subperiodic Brugia malayi infection in the leaf monkey (Presbytis melalophos) with diethylcarbamazine citrate
    Mak JW, Lim PK
    Z Parasitenkd, 1983;69(5):677-80.
    PMID: 6415950
    The chemoprophylactic use of diethylcarbamazine citrate at total oral doses of 15--180 mg/kg body weight was tested against subperiodic Brugia malayi infection in the leaf monkey (Presbytis melalophos). A total dose of 45 mg/kg body weight given over 9 days killed all developing infective larvae. Similarly, a total dose of 35 mg/kg body weight given over 7 days killed all fourth stage larvae. The minimum effective dose that prevents infection would be 5 mg/kg body weight daily for 7 days every month.
    Matched MeSH terms: Brugia/growth & development
  12. Enzyme polymorphism of the malaria vector, An. balabacensis (Diptera: Culicidae) revisited--why sample natural populations?
    Hii JL, Chew M, Vun YS, Nasir M, Chang MS
    Southeast Asian J Trop Med Public Health, 1988 Dec;19(4):689-701.
    PMID: 3238482
    Two separate observations from recent electrophoretic studies of the systematics and population genetics of laboratory-reared populations which had a long history of colonization in various laboratories, were found to be inconsistent with the present study which used wild-caught populations from East Malaysia. Reanalysis of the two data sets generally indicated a low amount of genetic variation in laboratory colonies. The latter is characterized by higher frequency of monomorphic loci, low average heterozygosity values and, in one extreme case, no variability at two loci. However, natural populations of An. balabacensis and An. leucosphyrus showed more protein variability by the use of polyacrylamide gel electrophoresis. Since laboratory-maintained mosquitoes are genetically and phenotypically different from those in the field, results of laboratory studies on the systematics and population genetics of Anopheles species complexes may be biased.
    Matched MeSH terms: Animals, Laboratory/growth & development
  13. Growth of arm circumference and triceps skinfold of Malay children from birth to six years of age
    Chen ST
    J Singapore Paediatr Soc, 1990;32(3-4):87-96.
    PMID: 2133762
    126 Malaysian children, 65 boys and 61 girls from higher income families were followed-up regularly from birth to six years of age in the University Hospital, Kuala Lumpur. The study shows that for boys and girls, there is a progressive increase in the left mid-upper arm circumference from birth to six years of age. However the rate of growth is not even, being most rapid during the first four month of infancy, then rapidly decreases during the middle third of infancy and thereafter it decreases slowly and by the second year of life, there is hardly any increase in the arm circumference. The left triceps skinfold thickness curves for boys and girls rise rapidly after birth to reach a peak at about three to five months before commencing to decline and then flatten off from the second year of life. The study also shows that on the whole, boys have slightly bigger arm circumference than girls during the first two years of life. From two years of age, girls on the average have more fat than boys. However this difference is statistically not significant at the ages tested. This paper also presents the left mid-upper arm circumference and left triceps skinfold percentile charts of Malaysian boys and girls from birth to six years of age.
    Matched MeSH terms: Arm/growth & development*
  14. Malaria of the orang-utan (Pongo pygmaeus) in Borneo
    Peters W
    Philos Trans R Soc Lond B Biol Sci, 1976 Sep 28;275(941):439-82.
    PMID: 10589
    The primary objective of this project was to study the life cycle and ecology of Plasmodium pitheci, a malaria parasite of the orang-utan. The field work was based on the orang-utan rehabilitation centre in the Sepilok Forest Reserve of eastern Sabah. Two visits were made to Sepilok, the first in February and March, 1972, and the second (by W.P.) in January 1974. On the first visit two species of "surrogate host" were taken to Sabah, i.e. chimpanzees and Aotus monkeys for experimental work. The arboreal habitat of the orang-utan in the dipterocarp forests of eastern Sabah is described. In the Sepilok Forest Reserve dwell gibbons and leaf-monkeys, in addition to a small population of semi-domesticated and wild, free-ranging orang-utans of various ages. Although numerous species of anopheline mosquitoes have been collected in eastern Sabah, longitudinal studies are not available. Anopheles balabacensis was caught both attracted to orang-utans and to man at Sepilok. This species which is the main vector of human malaria in the north of Borneo, is suspected also of transmitting orang-utan malaria in this part of Sabah. Repeated blood examinations have been made on a number of orang-utans in the centre since 1966 and a high prevalence of infection was recorded with Plasmodium pitheci. In 1966 10 out of 19 animals had demonstrable parasitaemia. Detailed case histories are presented to show the course of parasitaemia in several orang-utans. Infections of P. pitheci were found to run a very chronic course. During the 1972 expedition a second, previously undescribed malaria parasite of the orang-utan was discovered, and was named P. silvaticum. The new parasite was successfully transmitted both by blood inoculation and, later, by sporozoite inoculation, into splenectomized chimpanzees. Although both species of malaria parasite may cause transitory signs of illness, orang-utans in general appear to be little discomforted by the infection. The animals do however suffer from other infectious diseases such as amoebic and balantidial dysentery, and melioidosis is a serious natural hazard which may have accounted for several deaths of wild orang-utans. An unidentified, intraerythrocytic structure that appeared in the blood of one chimpanzee, which had been inoculated with blood from an orang-utan, may have contributed to its death. Detailed descriptions and illustrations of P. pitheci and P. silvaticum are given. All stages of the life cycle of P. silvaticum are known (the tissue stages having been described in the liver of a "surrogate host", the chimpanzee) but only the blood and sporogonic stages of P. pitheci have been seen. This species was not infective to a chimpanzee, although there is an earlier report of a transient infection in this host by other workers. In the blood both parasites showed a tertian periodicity. From the appearance of the tissue schizonts on the seventh day it was estimated that the complete pre-erythrocytic cycle of P. silvaticum in the chimpanzee would occupy 8 days. P...
    Matched MeSH terms: Plasmodium/growth & development
  15. Pseudomonas putrefaciens from clinical material
    Thong ML
    Southeast Asian J Trop Med Public Health, 1976 Sep;7(3):363-6.
    PMID: 1025737
    Three strains of Pseudomonas putrefaciens were isolated from routine clinical specimens at the University Hospital, Kuala Lumpur, Malaysia. Their cultural and biochemical characteristic, and antibiotic susceptibilities are presented. Characteristics of diagnostic value were stressed. Two isolates appeared to have played a pathogenic role in chronic otitis media.
    Matched MeSH terms: Pseudomonas/growth & development
  16. Fulltext Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba
    Yang Y, Li J, Yang S, Li X, Fang L, Zhong C, et al.
    BMC Evol. Biol., 2017 01 18;17(1):22.
    PMID: 28100168 DOI: 10.1186/s12862-016-0849-z
    BACKGROUND: A large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation.

    RESULTS: In this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation, which could facilitate mangrove establishment and adaptation in new habitats, especially in the context of global climate changes.

    CONCLUSION: Phylogeogrpahic analysis in this study reveal that Pleistocene sea-level fluctuations had profound influence on population differentiation of the mangrove tree S. alba. Our study highlights the fragility of mangrove plants and offers a guide for the conservation of coastal mangrove communities experiencing ongoing changes in sea-level.

    Matched MeSH terms: Rhizophoraceae/growth & development*
  17. Biofilm formation enhances Helicobacter pylori survivability in vegetables
    Ng CG, Loke MF, Goh KL, Vadivelu J, Ho B
    Food Microbiol, 2017 Apr;62:68-76.
    PMID: 27889168 DOI: 10.1016/j.fm.2016.10.010
    To date, the exact route and mode of transmission of Helicobacter pylori remains elusive. The detection of H. pylori in food using molecular approaches has led us to postulate that the gastric pathogen may survive in the extragastric environment for an extended period. In this study, we show that H. pylori prolongs its survival by forming biofilm and micro-colonies on vegetables. The biofilm forming capability of H. pylori is both strain and vegetable dependent. H. pylori strains were classified into high and low biofilm formers based on their highest relative biofilm units (BU). High biofilm formers survived longer on vegetables compared to low biofilm formers. The bacteria survived better on cabbage compared to other vegetables tested. In addition, images captured on scanning electron and confocal laser scanning microscopes revealed that the bacteria were able to form biofilm and reside as micro-colonies on vegetable surfaces, strengthening the notion of possible survival of H. pylori on vegetables for an extended period of time. Taken together, the ability of H. pylori to form biofilm on vegetables (a common food source for human) potentially plays an important role in its survival, serving as a mode of transmission of H. pylori in the extragastric environment.
    Matched MeSH terms: Biofilms/growth & development*
  18. Fulltext Investigation of the microbial communities colonizing prepainted steel used for roofing and walling
    Huynh TT, Jamil I, Pianegonda NA, Blanksby SJ, Barker PJ, Manefield M, et al.
    Microbiologyopen, 2017 04;6(2).
    PMID: 27998037 DOI: 10.1002/mbo3.425
    Microbial colonization of prepainted steel, commonly used in roofing applications, impacts their aesthetics, durability, and functionality. Understanding the relevant organisms and the mechanisms by which colonization occurs would provide valuable information that can be subsequently used to design fouling prevention strategies. Here, next-generation sequencing and microbial community finger printing (T-RFLP) were used to study the community composition of microbes colonizing prepainted steel roofing materials at Burrawang, Australia and Kapar, Malaysia over a 52-week period. Community diversity was low and was dominated by Bacillus spp., cyanobacteria, actinobacteria, Cladosporium sp., Epicoccum nigrum, and Teratosphaeriaceae sp. Cultivation-based methods isolated approximately 20 different fungi and bacteria, some of which, such as E. nigrum and Cladosporium sp., were represented in the community sequence data. Fluorescence in situ hybridization imaging showed that fungi were the most dominant organisms present. Analysis of the sequence and T-RFLP data indicated that the microbial communities differed significantly between locations and changed significantly over time. The study demonstrates the utility of molecular ecology tools to identify and characterize microbial communities associated with the fouling of painted steel surfaces and ultimately can enable the targeted development of control strategies based on the dominant species responsible for fouling.
    Matched MeSH terms: Biofilms/growth & development*
  19. Patterns in the morphological variation of Zonorchis and Skrjabinus (Trematoda: Dicrocoelidae) from small mammals in Malaysia
    Betterton C, Lim BL
    Int J Parasitol, 1977 Feb;7(1):73-82.
    PMID: 404265
    Matched MeSH terms: Trematoda/growth & development
  20. Experimental infection of Rattus sabanus and Rattus muelleri with subperiodic Brugia malayi
    Sivanandam S, Mak JW, Lai PF
    Southeast Asian J Trop Med Public Health, 1975 Mar;6(1):68-73.
    PMID: 1145240
    R. sabanus and R. muelleri are very common in the lowland forests of Malaysia. In nature they are infected with Breinlia sp. and D. ramachandrani. In an attempt to determine whether they are also susceptible to subperiodic B. malayi and thereby being potential reservoirs of infection of the disease, 24 R. muelleri and 17 R. sabanus were experimentally infected with the parasite. Results show that although they can support the full development of the parasite, they are poor hosts. This confirms the observation that in Malaysia natural infection of Rattus spp. with the parasite has not been seen. These rats therefore are probably not important in the zoonotic transmission of subperiodic B. malayi in Malaysia.
    Matched MeSH terms: Brugia/growth & development
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