Displaying publications 1 - 20 of 36 in total

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  1. Yap KL
    Malays J Pathol, 1994 Jun;16(1):49-56.
    PMID: 16329576
    The aim of this study was to optimize the conditions for the passive adsorption of polyclonal antibody onto plain surface polystyrene latex particles and its performance in a slide latex agglutination test for rotavirus antigen detection. Cleaning of latex particles by washing through repetitive centrifuging, decanting and resuspending in distilled water was adequate in removing surfactants from the particles' surfaces to enable coating. A study of antibody concentration, incubation temperature and buffer pH revealed that optimum coating was achieved with a 3-fold excess of antibody to the calculated total particle surface capacity for the antibody in a glycine-saline buffer of pH 9.2 at 40 degrees C for 4 hours. The ionic strength and pH of the latex suspending buffer and the sample buffer were critical factors determining the sensitivity of the test and the appearance of non-specific agglutination. Ultrasonication, addition of glycerol and Tween 20, either individually or in combination, were able to suppress non-specific agglutination in some batches of latex reagents. Polyethylene glycol 6000 enhanced the quality of agglutination as well as reduced the time of its appearance, especially in reagents that produced poor agglutination.
  2. Awang A, Yap K
    J Diarrhoeal Dis Res, 1990 Sep;8(3):82-6.
    PMID: 2122998
    Randomly selected samples from different animal colonies from two laboratory animal houses and from the wild-caught monkeys were tested for the presence of anti-rotavirus antibodies to estimate the rates of infection with group A rotavirus. Antibodies to the common group A rotaviral antigen were detected by a competitive enzyme-linked immunosorbent assay (ELISA) using reagents of WHO ELISA rotavirus detection kit. The results of the study showed that white mice, albino rats, and guinea pigs from long-established breeding colonies and resident house rats and house shrews from the animal house had no serological evidence of rotaviral infection. In contrast, one mousedeer from a colony of 19 animals and most of the rabbits from two separate breeding colonies at the same animal house were serologically positive for the infection. Also a significant number of the same species of monkey kept in captivity were found to acquire the infection. Leaf monkeys had no serological evidence of rotaviral infection. The infection rate in wild cynomolgus monkeys did not seem to be influenced by the different ecological environments of their respective habitats. The rate of infection in adults and juveniles was similar.
  3. Yap KC, Aminah A
    Int J Cosmet Sci, 2011 Jun;33(3):245-50.
    PMID: 21272038 DOI: 10.1111/j.1468-2494.2010.00621.x
    Sensory analysis of lipstick product by trained panellists started with recruiting female panels who are lipstick users, in good health condition and willing to be a part of sensory members. This group of people was further scrutinized with duo-trio method using commercial lipstick samples that are commonly used among them. About 40% of the 15 panels recruited were unable to differentiate the lipstick samples they usually use better than chance. The balance of nine panels that were corrected at least with 65% across all trials in panels screening process was formed a working group to develop sensory languages as a means of describing product similarities and differences and a scoring system. Five sessions with each session took about 90 min were carried out using 10 types of lipsticks with different waxes mixture ratio in the formulation together with six commercial lipsticks that are the most common to the panels. First session was focus on listing out the panels' perception towards the characteristic of the lipstick samples after normal application on their lips. Second session was focus on the refining and categorizing the responses gathered from the first session and translated into sensory attributes with its definition. Third session was focus on the scoring system. Fourth and fifth sessions were repetition of the third session to ensure consistency. In a collective effort of the panels, sensory attributes developed for lipstick were Spreadability, Off flavour, Hardness, Smoothness, Moist, Not messy, Glossy and Greasy. Analysis of variance was able to provide ample evidence on gauging the panel performance. A proper panels selecting and training was able to produce a reliable and sensitive trained panel for evaluating the product based on the procedures being trained.
  4. Yap KH, Sulaiman S
    Singapore Med J, 2009 Jul;50(7):e247-9.
    PMID: 19644610
    Pulmonary atelectasis may be caused by endobronchial lesions or by extrinsic compression of the bronchus. However, lung collapse due to compression from a thoracic aneurysm is uncommon. We report a 76-year-old hypertensive female patient who has pulmonary atelectasis due to an extrinsic compression from a descending thoracic aortic aneurysm, and discuss possible treatment options.
  5. Lim JKH, Yap KB
    Med J Malaysia, 2001 Jun;56(2):232-5.
    PMID: 11771085
    This study aims to investigate the incidence and causes of hyponatraemia in hospitalised elderly patients. There was a total of 407 new patients. 55 (13.5%) patients were found to have at least one episode of hyponatraemia during their hospitalization. There were 58 deaths. Fifteen out of 55 (27.3%) patients who had hyponatraemia died compared to 43 out of 352 (12.2%) normonatraemic patients (chi-square significant, p < 0.01). The three most common causes of hyponatraemia were syndrome of inappropriate antidiuretic hormone secretion (SIADH), poor oral intake and diuretics. The two most common causes of SIADH were lower respiratory tract infection and stroke.
  6. Paranjothy M, Yap KL, Sabil D
    Med J Malaysia, 1987 Mar;42(1):31-5.
    PMID: 2828895
    A prospective clinical study comparing 74 cases of rotavirus-associated diarrhoea and 100 cases of non-rotavirus-associated diarrhoea revealed a higher incidence of vomiting to be the only significant difference in the former. Bloody stools were seen in about 5-10%, fever in about two-thirds and respiratory symptoms in a quarter of cases regardless of aetiology. The overwhelming majority had mild dehydration of the isonatremic type. Hypokalemia was noted in a quarter of the cases in both groups.
    Keywords: General Hospital Kuala Lumpur
  7. Flaherty GT, Lim Yap K
    J Travel Med, 2017 Sep 01;24(5).
    PMID: 28498914 DOI: 10.1093/jtm/tax024
    Evidence-based travel medicine requires that research priorities reflect the wide knowledge base of this discipline. Bibliometric analysis of articles published in Journal of Travel Medicine yielded the following results: epidemiology (6%, n = 105); immunology/vaccinology (8.5%, n = 148); pre-travel assessment/consultation (30.5%, n = 533); diseases contracted during travel (48.3%, n = 843); other clinical conditions associated with travel (6.8%, n = 119); post-travel assessment (5.2%, n = 91) and administrative and general travel medicine issues (6%, n = 105).
  8. Yap KL, Hu KN
    PMID: 19058604
    The importance of bacteria-suspending media and fingertip positions on the survival of Vibrio cholerae on human fingertips were examined. Vibrios were suspended in phosphate-buffered saline (PBS), PBS with albumin, and PBS with agarose. Each type of preparation was inoculated on the fingerpads, the hyponychia, or the eponychia and lateral nail grooves of the fourth, third and second fingers of a volunteer's hand. The last finger inoculated was immediately washed with PBS and the washing collected for examination ("0 minute" exposure). The third and fourth inoculated fingers were likewise washed for examination 2 and 5 minutes later, respectively. The vibrios obtained from the washings were enumerated by culture. For each of the different groups, which consisted of a different inoculated fingertip position, bacteria-suspending medium and exposure period of 2 or 5 minutes, the proportion of replicate inoculated fingers which retained viable vibrios (isolation rate) and the mean number of surviving vibrios, as a percentage of the inoculated vibrios at "0 minute exposure" (survival rate) were as follows: finger pads: vibrios in PBS, 2 minutes post-inoculation (isolation rate, 25%; mean survival rate, 0.002%); 5 minutes post-inoculation (isolation rate, 0%; mean survival rate, 0%). PBS-albumin: 2 minutes post-inoculation (60%, 0.004%); 5 minutes post-inoculation (40%, 0.03%). PBS-agarose: 2 minutes post-inoculation (100%, 24%); 5 minutes post-inoculation (38%, 0.005%). Lateral nail grooves and eponychia: PBS: 2 minutes post-inoculation (100%, 2.2%); 5 minutes post-inoculation (44%, 0.2%). PBS-agarose: 2 minutes post-inoculation (100%, 32%); 5 minutes post-inoculation (100%, 0.7%). Hyponychia: PBS: 2 minutes post-inoculation (100%, 8%); 5 minutes post-inoculation (100%, 0.2%). PBS-agarose: 2 minutes post-inoculation (100%, 46%); 5 minutes post-inoculation (100%, 8%). The results show that vibrios in moisture-retaining medium (PBS-agarose) and inoculated on a sheltered fingertip locations (hyponychium) have the best survival rates. However, the high survival rate was maintained briefly.
  9. Lee ASC, Yap KL
    PMID: 10774695
    Poliovirus kept on the cut surfaces of fully ripe papaya cubes placed in an ice box showed a sharp and significant reduction in the recovery of infectious virus about 15 minutes after exposure. Thereafter, a very gradual decrease ensued and infectious residual virus was detected up to the end of the 6-hour exposure period. Papaya cubes washed or kept overnight before virus inoculation, and from less ripe fruits produced a similar survival pattern. A very small proportion of the inoculum was recovered from the mashed content of the inoculated papaya cubes thus suggesting that most of the non-recovered virus particles were inactivated. The results suggest that the importance of poliovirus-contaminated cut papayas as a transmission vehicle for the virus is greatly reduced by the rapid decline in the infectivity of a large proportion of the virus soon after contamination. Nevertheless, the potential to transmit remains as a small residual pool of infectious poliovirus is able to survive for a relatively long period.
  10. Yap KL, Lam SK
    J Virol Methods, 1994 Apr;47(1-2):217-26.
    PMID: 8051228
    A simple, rapid and objective infectivity assay based on an in situ enzyme immunoassay (EIA) was developed for the fast-growing and cytopathic cell culture-adapted hepatitis A virus (HAV) strain HM175A.2. Infectivity titration by EIA correlated well with titration by cytopathic effects. The reliability of this assay was demonstrated by close agreement in virus infectivity titers among different assays of the same virus aliquot and between assays of different virus aliquots. HAV infected cell cultures after fixation could be stored for up to 1 week before testing without decline in virus titer.
  11. Tan CK, Huang YQ, Yap KB
    Med J Malaysia, 2013 Oct;68(5):443-4.
    PMID: 24632878
    Vancomycin has been documented to cause various adverse cutaneous reactions. We present a case report of a man, who developed a large localized erythematous plaque in his forearm following parenteral vancomycin therapy. We believe this to be the first reported case of such cutaneous reaction associated with parenteral vancomycin therapy.
  12. Yap KL, Lim YH, Tan SC
    Malays J Pathol, 1998 Jun;20(1):25-30.
    PMID: 10879260
    The objective of this study was to ascertain the extent changes have occurred in the epidemiology of human rotavirus electropherotypes from the same location 7 to 8 years after an earlier study. Genomic RNA profiles of rotaviruses from diarrhoeic children admitted to the Kuala Lumpur Hospital from April to December 1996 were determined by polyacrylamide gel electrophoresis and silver staining. A total of 179 group A rotaviruses were detected from 870 children: 175 with legible staining of all RNA segments were classified into 14 distinct electropherotypes (10 and 4 with long and short migration patterns respectively). In addition, the results revealed: high predominance of long pattern electropherotypes (94% of the total electropherotypes); most long electropherotypes with RNA profiles which all 11 RNAs migrated separately (8 of 10 electropherotypes); all short electropherotypes had segments 2 and 3 that co-migrated; presence of a very numerically dominant electropherotype (75% of all electropherotypes); frequent co-circulation of the dominant electropherotype-present throughout the study period--with other electropherotypes present for limited periods; sequential temporal appearances by similar electropherotypes. These observations were similar to that of an earlier study conducted in 1988/89. Nevertheless, the dominant electropherotype in the present study was different and not among the electropherotypes detected in the earlier study.
  13. Abdul Samad S, Yasin MS, Arumugham G, Yap KL
    Malays J Pathol, 1993 Dec;15(2):119-23.
    PMID: 8065172
    An invasive aspergillosis model in rabbits was attempted using 3 concentrations of A. fumigatus conidia. Conidia concentrations of 1 x 10(6), 1 x 10(7) and 1 x 10(8) were inoculated intravenously into rabbits. The severity of infection was directly proportional to the inoculum size of the conidia. Aspergillus fumigatus was isolated from livers, kidneys, spleens, hearts and lungs of infected rabbits at a rate of 82%, 75%, 57%, 54% and 32% respectively. Cultures of urine specimens taken by bladder tap were positive for A. fumigatus in 30% of the rabbits tested. Blood cultures using the Bactec Fungal System (Becton Dickinson Corp., USA) failed to isolate A. fumigatus in 20 rabbits with biopsy-proven invasive apergillosis. Active infection with high fungal tissue burden occurred between 2-4 days after infection in rabbits inoculated with 1 x 10(7) conidia.
  14. Tan SW, Yap KL, Lee HL
    J Med Entomol, 1997 Sep;34(5):527-31.
    PMID: 9379457
    Factors affecting the mechanical transmission of rotavirus by the legs and wings of the housefly, Musca domestica L., were examined in a laboratory study. Rotavirus was picked up when houseflies walked on thin smears of clarified rotavirus suspensions. The addition of glycerol, which increased viscosity of the virus suspension, and particulate human feces slightly increased the proportion of flies contaminated with virus. However, the addition of glycerol greatly reduced the average number of virus particles picked up per fly, whereas feces greatly increased the number of particles. The proportion of flies with virus-contaminated legs, which transferred virus to > 1 contact surface, was increased by longer contact time with the surface and when the contact surface was agar instead of glass. Most virus particles were deposited on 1st contact with the surface. Most flies dislodged virus particles inoculated on the underside of their wings soon after the start of simulated flight. Our data indicated that the nature of the virus-suspending medium has a greater effect on the level of virus contamination than on the ability to become contaminated. The importance of walking as a mode of virus transport depends on the nature of the contact surface, the risk of the contaminated fly settling first on a surface likely to come into contact with humans, and fly numbers.
  15. Yap KL, Boo NY, Surayah O
    Malays J Pathol, 1994 Jun;16(1):89-91.
    PMID: 16329583
    The pattern of rotavirus infection in babies of the neonatal special care nursery (SCN) of the Kuala Lumpur Maternity Hospital was studied. The presence of rotavirus in the neonates' stools was ascertained using the method of polyacrylamide gel electrophoresis and silver staining. No rotavirus was detected in the 511 stools and rectal swabs collected from the 164 neonates over a 8-week period. Thus the babies admitted to the SCN from the labour rooms and the postnatal wards of the hospital were unlikely to be carriers of rotavirus or infected by rotavirus during their stay. It was concluded that rotavirus was not endemic in the nursery or the postnatal wards of this maternity hospital.
  16. Nelson Yap KB, Albert Wong SH, Idris Z
    Med J Malaysia, 2020 11;75(6):660-665.
    PMID: 33219174
    BACKGROUND: Some surgeons advocate the usage of tranexamic acid (TXA) in traumatic brain injury (TBI). The aim of this study is to determine the effectiveness and safety of TXA in improving the outcome of TBI patients and in reducing the rate of clot expansion and mortality in TBI as compared to those without TXA.

    METHODS: This is a prospective observational cohort study conducted in Sarawak General Hospital, Malaysia. Patients 12 years of age and older with mild to severe TBI who had a brain computed tomography (CT) done within eight hours of injury were enrolled in the study. A total of 334 patients were recruited from the 5th of August 2016 until the 8th of March 2018 in Sarawak General Hospital. In all 167 of them were administered with TXA and another 167 of the patients were not. The primary outcome expected is the number of good outcomes in isolated TBI patients given TXA. Good outcome is defined by Glasgow Outcome Score-Extended (GOSE) of five and above. Secondary outcome was clot expansion of an intracranial bleed seen on the first scan that had expanded by 25% or more on any dimension on the second scan.

    RESULTS: The TXA did not show significant trend of good outcome in terms of GOSE (p=0.763). However, for moderate and severe acute subdural haemorrhage (SDH) subgroups, there was a significant difference (p=0.042). Clot expansion was present in 14 patients (12.7%) with TXA given and in 54 patients (38.8%) without TXA. The difference was statistically significant (p<0.001). Of the patients who received TXA, there was one case (0.6%) of deep vein thrombosis. Apart from that, TXA showed non-significant trend in reducing mortality (p=0.474).

    CONCLUSIONS: Tranexamic acid reduces the rate of clot expansion in TBI by 26.1% (38.8-12.7%) without significantly increasing the risk of a thrombotic event. It can also improve the outcome of moderate and severe TBI patients with acute SDH.

  17. Yap KL, Kalpana M, Lee HL
    Trop Biomed, 2008 Apr;25(1):1-8.
    PMID: 18600198
    The importance of house fly (Musca domestica L) wings in mechanical transmission of bacteria was studied. A droplet of phosphate-buffered saline containing Vibrio cholerae was rolled along one wing of each house fly. None adhered to the wings but small proportions of the bacterium were isolated from about half the wings. Vibrio cholerae was spread onto the ventral wing surfaces of each unconscious house fly which then was placed inside a bottle. When it regained consciousness, the types of activity it performed over five minutes were noted before the house fly was killed and the bacteria on its wings numerated. Control were house flies killed before inoculation. The proportion of house flies with bacteria on their wings and the mean number of bacteria remaining were significantly less on live house flies than killed controls. Among the live house flies, bacteria were detected on fewer house flies which flew (25%) than those which did not fly (81%). In addition, the mean number of bacteria on the former was significantly less than the latter (5 against 780 colonies). However, both these parameters were not significantly different between the group which performed and the group which did not perform wing grooming; takeoff and alighting over short distances, and somersaulting. Wings of unconscious house flies tethered by their thoraxes were inoculated with V. cholerae. After regaining consciousness, the house flies were allowed to move their wings in flight motions for up to 30 seconds. Small proportions of bacteria remained on all the house flies. House flies were placed in a chamber containing a liquid bait spiked with V. cholerae. After two hours, 10 were removed sequentially and cultured for V. cholerae. The bacterium was isolated from four house flies: two from the legs, and two others from their bodies minus legs and wings. In conclusion, house fly wings do not play an important role in mechanical transmission of bacteria suspended in a non-adhering liquid medium because of the low transfer rate of the bacteria to the wings and poor retention of bacteria on the wings during normal house fly activities.
  18. Lee, C. M., Gan, Y. L., Chan, Y. L., Yap, K. L., Tang, T. K., Tan, C. P., et al.
    MyJurnal
    The primary objectives of the present work were to produce corncob powder (CCP) from
    corncobs and incorporate the CCP into bread formulation in order to develop high fibre bread,
    and to investigate the physicochemical and sensory properties of the produced high fibre
    bread (HFB). The corncobs were collected and washed before they underwent the grinding
    and drying processes. The obtained CCP was incorporated into the bread formulation in three
    different proportions (5, 10 and 20%) to partially substitute bread flour in the formulation. All
    three bread samples and the control (0% CCP in the formulation) were analysed to obtain their
    physicochemical and sensory properties. The incorporation of CCP significantly affected the
    texture, colour and volume attributes of the produced breads. Increasing the content of CCP
    in the formulation was found to be responsible for firmer, smaller and darker bread loaves as
    compared to the composite bread samples. The bread formulation incorporated with 10% CCP
    had the highest mean scores (7.00) of overall acceptability among all the other formulations,
    and it was comparable to the commercial breads in the current market.
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