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Biomedical subjects

K B Lim

Publications and source records attributed to K B Lim.

At least 19 recordsLinked to original sources
PubMed2005

Atypical presentations of emphysematous cystitis.

Emphysematous cystitis is an uncommon infection of the bladder with the formation of carbon dioxide either within the bladder or within its wall. It is commonly seen in women and those with poorly controlled diabetes mellitus, in association with some form of urinary stasis and obstruction. The clinical features are very varied and the outcome is often unpredictable. Radiography may reveal a radiolucent line around the bladder wall or gas within the bladder. Occasionally, computed tomography scans are required to help in the diagnosis due to their atypical presentation with acute abdominal pain. Herein, we report three patients with such a condition who were treated with favourable outcomes. Of the three patients, two had to undergo exploratory laparotomy due to their initial presentations with acute abdomens.

Aged↗
PubMed2005

Validity and reliability of the SF-36: the Malaysian context.

Results of construct validity and reliability of the SF-36 are described, based on data from a multi-centre study on asthmatics and a population based survey. Questionnaire refinement was carried out between the two studies. Quality of data was good, with all items having less than 0.5% missing values. Floor and/or ceiling effects were observed for REE, REP, PF and SF. For scaling assumptions, correlations between each items and its hypothesized scale were all above 0.50, except for one item in PF. and for both items in SF. Item discriminant validity was an issue for items in VT, SF and MH scales. Cronbach's as for all scales exceeded the recommended 0.70 level, except for SF. Only one latent dimension was identified in principal component analysis, and only 52-53% of variance accounted for. As expected, PF shows high correlations with the physical component while MH was highly correlated with the mental component. Contrasting findings in the loadings of other scales were observed in the asthma data. Age, disease severity and presence of self-reported handicap/disability significantly affect PF, while MH demonstrates no obvious pattern with declining age. In essence, the Malay version of SF-36 could be used in Malaysia, with its generally acceptable internal consistency and validity. The caveat is in the call for additional domains of importance to Malaysians that is not covered by the instrument, and in the caution to be employed when using and construing the instrument.

Adolescent↗
PubMed2004

Use of 2n gametes for the production of sexual polyploids from sterile Oriental x Asiatic hybrids of lilies (Lilium).

Sixteen Oriental and 12 Asiatic cultivars were crossed in 158 different combinations. A total of 708 F1 hybrids were obtained from 86 of the different combinations of 15 Oriental and 11 Asiatic cultivars. Because the Lilium cultivars (2n=2x=24) used for the production of these hybrids belong to two different taxonomic sections-Archelirion (0) and Sinomartagon (A), respectively-the F1 hybrids (OA) could be obtained only through embryo, embryo sac rescue, ovary slice or ovule culture. Most of the F, hybrids were highly sterile (did not produce viable n gametes) due to the failure of chromosome pairing. However, in a few cases F1 plants were found that produced viable 2n pollen at variable frequencies. These 2n pollen grains were successfully used for the production of backcross progenies. Using genomic in situ hybridization we found intergenomic recombinant chromosomes in the sexual polyploid progenies. These results indicate that there are effective prospects for combining important horticultural traits from the two main groups of cultivars of lilies through sexual polyploidization.

Chromosome Mapping↗
PubMed2004

Transurethral resection of prostate (TURP) through the decades--a comparison of results over the last thirty years in a single institution in Asia.

INTRODUCTION: This study was conducted to evaluate the results and complications of transurethral resection of prostate (TURP) over the last 30 years in our institution. MATERIALS AND METHODS: This retrospective study encompasses 3 different eras: 168 patients in the late 70s, 175 patients in the late 80s and 283 patients in the late 90s. All the patients had at least 18 months of follow-up. RESULTS: The mean age from the 1970s, the 1980s and 1999 were 68.8 years, 69.2 years and 69.4 years respectively. The proportion of patients operated on for acute retention fell from 78.6% (132) in the 1970s, to 54% (96) in the 1980s, and 43% (122) in 1999. The mean resection time was 44.8 minutes in 1989 and 41.8 minutes in 1999. The mean weight of prostate resected was 22.1 g in the 1970s, 24.2 g in 1989 and 22.2 g in 1999. 44% (74) required blood transfusion in the 1970s, with 11% (19) in 1989 and 4% (11) in 1999. There were 2 deaths (acute myocardial infarction and pneumonia) in the 1970s, 1 (pneumonia) in 1989 and no mortality in 1999. There were 4 patients with TURP syndrome in the 1970s, 3 in 1989 and 1 in 1999. The incidence of postoperative urinary tract infection (UTI) was 25% (42) in the 1970s, 16% (29) in 1989 and 6% (17) in 1999. CONCLUSIONS: As expertise and experience in TURP progress, the complication rates fall, as evidenced by the lower rates of transfusion, TURP syndrome and postoperative UTI in the later series.

Aged↗
PubMed2002

Randomised clinical trial of suture compared with adhesive strip for skin closure after HRT implant.

To determine which method of skin closure was associated with less bleeding, 250 women were randomly allocated to have either a suture closure (3-0 Dexon II) or an adhesive strip closure (Steri-Strip) following subcutaneous insertion of hormone (HRT) implants. Data were collected via a tested questionnaire and analysed. Significantly, more women in the adhesive strip group recorded postprocedure bleeding (RR = 2.26; 95% CI 1.42-3.60) and considered the bleeding excessive (RR = 4.17; 95% CI 1.18-14.76) and unacceptable (RR = 12.52; 95% CI 1.63-96.19). Pain scores and symptoms of local infection were similar in both groups. Routine use of adhesive strips for implant skin incision closure is not recommended.

Bandages↗
PubMed2001

Induction of apoptosis in mammary gland by a pure anti-estrogen ICI 182780.

The antiestrogen, ICI 182780 (ICI) proves to be clinically useful for the treatment of estrogen receptor positive breast tumours. We report the assessment of the in vivo and in vitro effects of ICI on apoptosis of breast epithelial cells. In vivo, administration of rats with ICI for 3 weeks resulted in a reduction in the size of the lobular structures with the rate of mammary epithelial apoptosis equivalent to 10, 35 and 45% on treatment with 1, 1.5 and 2 mg ICI per kg body weight, respectively. Concomitantly, these treatment led to a 2.0-, 2.2- and 2.5-fold increase in Bax. Similar elevations were also observed in Bad levels which increased 1.7-, 2.6- and 2.7-fold respectively in the ICI treatment as compared to controls. This also resulted in a dose dependent decrease in Bcl-2 and Bcl-xL protein expressions. Growth inhibition and induction of apoptosis were also observed in the MCF-7 cells following in vitro treatment with ICI. This is closely associated with [1] the down-regulation of Bcl-2 and Bcl-xL proteins and [2] upregulation of Bax and Bad, whose gene products are known to be involved the regulation of apoptosis in mammalian cells. Stable over-expression of Bcl-2 resulted in protection of MCF-7 cells from apoptosis and growth inhibitory effects of ICI. Conversely, reduction of Bcl-2 by antisense transfection make MCF-7 cells more sensitive to ICI-induced growth inhibition and apoptosis. These findings suggest that modulation of Bax, Bcl-xL, Bcl-2 and Bad proteins by ICI may be, in part, responsible for the anti-proliferative and apoptotic effect of ICI seen clinically and in animal models.

Animals↗
PubMed2001

Induction of UO-44 gene expression by tamoxifen in the rat uterus and ovary.

A complementary DNA, uterine-ovarian-specific gene 44 (UO-44), has been isolated from tamoxifen-induced rat uterine complementary DNA library using differential display techniques. UO-44 transcripts are found to be abundant in the uterus and ovary. UO-44 gene expression in the uterus is strictly regulated by estrogens, tamoxifen, and GH, whereas the pure antiestrogen ICI 182780 is inhibitory. Treatment of ovariectomized rats and hypophysectomized rats with tamoxifen and GH, respectively, resulted in up-regulation of UO-44 expression in a dose-dependent manner. In situ hybridization revealed that UO-44 gene expression was restricted to the luminal and glandular epithelial cells of the uterus and to granulosa cells of medium-size ovarian follicles. Transfection studies showed that UO-44 was a membrane-associated protein. Because estrogens, tamoxifen, and GH are stimulators of uterine luminal epithelial cell growth in vivo, UO-44 protein may serve as a mediator of the effect of these compounds in inducing epithelial proliferation and differentiation in these tissues.

Animals↗
PubMed2001

Cloning and characterization of a novel pregnancy-induced growth inhibitor in mammary gland.

Growth factors and growth inhibitors play crucial roles in the growth regulation and differentiation of mammary epithelial cells. Studies have shown that during pregnancy, with the onset of terminal differentiation, there is a dramatic decrease in the proliferation of the mammary epithelial cells. Here we report the cloning and characterization of a novel pregnancy-induced cDNA, OKL38, from a human ovarian cDNA library. This cDNA encodes for a protein of approximately 34.5 kDa. Tissue distribution studies through Northern analyses revealed the ubiquitous nature of OKL38 transcripts in most tissues, with the highest levels observed in the ovary, kidney, and liver. The onset and advancement of pregnancy also gave rise to a concomitant increase in OKL38 gene expression. In situ hybridization revealed that OKL38 mRNA was further detected in mammary secretory epithelial cells. However, low levels of OKL38 transcripts were observed in the various human breast cancer cell lines studied and were barely detectable in all dimethylbenz(A)anthracene-induced mammary tumors examined. Transfection studies with OKL38 cDNA with MCF-7 cells resulted in growth inhibition in vitro and reduction in tumor formation in vivo. These observations led to speculation that OKL38 may play a vital role in the growth regulation and differentiation of breast epithelial cells during pregnancy and its implications in tumorigenesis.

Amino Acid Sequence↗
PubMed2001

Karyotype analysis of Lilium longiflorum and Lilium rubellum by chromosome banding and fluorescence in situ hybridisation.

Detailed karyotypes of Lilium longiflorum and L. rubellum were constructed on the basis of chromosome arm lengths, C-banding, AgNO3 staining, and PI-DAPI banding, together with fluorescence in situ hybridisation (FISH) with the 5S and 45S rDNA sequences as probes. The C-banding patterns that were obtained with the standard BSG technique revealed only few minor bands on heterologous positions of the L. longiflorum and L. rubellum chromosomes. FISH of the 5S and 45S rDNA probes on L. longiflorum metaphase complements showed overlapping signals at proximal positions of the short arms of chromosomes 4 and 7, a single 5S rDNA signal on the secondary constriction of chromosome 3, and one 45S rDNA signal adjacent to the 5S rDNA signal on the subdistal part of the long arm of chromosome 3. In L. rubellum, we observed co-localisation of the 5S and 45S rDNA sequences on the short arm of chromosomes 2 and 4 and on the long arms of chromosomes 2 and 3, and two adjacent bands on chromosome 12. Silver staining (Ag-NOR) of the nucleoli and NORs in L. longiflorum and L. rubellum yielded a highly variable number of signals in interphase nuclei and only a few faint silver deposits on the NORs of mitotic metaphase chromosomes. In preparations stained with PI and DAPI, we observed both red- and blue-fluorescing bands at different positions on the L. longiflorum and L. rubellum chromosomes. The red-fluorescing or so-called reverse PI-DAPI bands always coincided with rDNA sites, whereas the blue-fluorescing DAPI bands corresponded to C-bands. Based on these techniques, we could identify most of chromosomes of the L. longiflorum and L. rubellum karyotypes.

Chromosome Banding↗
PubMed2000

Escherichia coli alpha-hemolysin (HlyA) is heterogeneously acylated in vivo with 14-, 15-, and 17-carbon fatty acids.

alpha-Hemolysin (HlyA) is a secreted protein virulence factor observed in certain uropathogenic strains of Escherichia coli. The active, mature form of HlyA is produced by posttranslational modification of the protoxin that is mediated by acyl carrier protein and an acyltransferase, HlyC. We have now shown using mass spectrometry that these modifications, when observed in protein isolated in vivo, consist of acylation at the epsilon-amino groups of two internal lysine residues, at positions 564 and 690, with saturated 14- (68%), 15- (26%), and 17- (6%) carbon amide-linked side chains. Thus, HlyA activated in vivo consists of a heterogeneous family of up to nine different covalent structures, and the substrate specificity of the HlyC acyltransferase appears to differ from that of the closely related CyaC acyltransferase expressed by Bordetella pertussis.

Acylation↗
PubMed2000

Introgression of Lilium rubellum Baker chromosomes into L. longiflorum Thunb.: a genome painting study of the F1 hybrid, BC1 and BC2 progenies.

Interspecific hybrids between Lilium longiflorum (L, 2n = 2x = 24) and Lilium rubellum (R, 2n = 2x = 24) were produced with the aim of transferring desirable horticultural traits from L. rubellum to L. longiflorum. All F1 hybrids (LR, 2n = 2x = 24) and BC1 individuals (LLR, 2n = 3x = 36) were phenotypically uniform for plant height, flowering time, leaf shape and flower colour. The BC1 plants were, in spite of their triploid nature, fertile and could be used as a female parent in backcrossings with autotetraploid L. longiflorum (LLLL, 2n = 4x = 48). Twelve BC2 individuals were obtained and three of them were selected for further chromosome analysis. As L. longiflorum and L. rubellum chromosomes were indistinguishable in the hybrids, genomic in-situ hybridization (GISH) was applied to establish the parentage of the chromosomes of the F1 hybrids and the BC1 and BC2 progenies. GISH confirmed the LLRR constitution of the doubled amphimonoploid (allodiploid), and the LLR constitution of all BC1 plants. The three selected BC2 plants were, as expected, aneuploid, containing three complete sets of L. longiflorum chromosomes and six, seven or eight L. rubellum chromosomes, respectively. However, L/R translocation or recombinant chromosomes could not be demonstrated in the mitotic metaphase complements of the F1, BC1 and BC2 plants. In spite of the high frequencies of homoeologous recombination in the F1 hybrids (LR) pollen was found to be sterile in all cases. At metaphase I of the pollen mother cells of the BC1 plants, genome painting did not reveal any cases of homoeologous pairing and recombination between L and R chromosomes. This lack of exchange between homoeologous chromosome segments indicates complete preferential pairing of the L and R chromosomes in the F1 (amphidiploid) and BC1 plants. It seems that the preferential pairing in the F1 and BC1 hybrids hinder the introgression of the chromosome segments or species-specific genes into the recipient for breeding purposes.

Chimera↗
PubMed2000

Thermographic study of palmar and facial skin temperature of hyperhidrosis patients before and after thoracic sympathectomy.

PURPOSE: The purpose of this study was to investigate the roles of the second thoracic sympathetic segment in the sympathetic innervation of the hands and face, and to compare skin temperature changes in the palms, fingers, face, and neck of palmar hyperhidrosis (PH) patients before and after endoscopic thoracic sympathectomy. METHODS: Twenty-two patients, 14 women and eight men, with severe PH were treated with endoscopic ablation of the T2 segment. The skin temperatures of the hands, neck, and face were assessed by infrared thermography both before and after operation. RESULTS: All obtained satisfactory relief of PH. Before sympathectomy, thermography revealed that the palmar skin temperature (PST) was significantly lower than the facial temperature by 1.3 degrees C (paired t-test, p < 0.005). After sympathectomy, thermography showed significant elevations in temperature mainly of the thenars, palms, digits, and nose, but not of the forehead, mandible, or neck (ANOVA, p < 0.05 with Bonferroni t-test). The variations in PST among PH patients were much greater preoperatively than postoperatively. More prominent postoperative PST elevation was found in PH patients with lower preoperative PST (r = 0.898, p < 0.001). CONCLUSIONS: These findings demonstrate that the T2 segment is the key source of sympathetic innervation to the hand and that the T2 segment contributes only trivial sympathetic innervation to the face. The results of the present thermography studies offer descriptive information about the autonomic innervation of the upper thoracic sympathetic trunk.

Adolescent↗
PubMed1999

Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa.

Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease.

Acylation↗
PubMed1999

The outcome of trial off catheter after acute retention of urine.

The aim of this study was to analyse the outcome of trial off catheter for patients who were admitted to the Department of Urology, Singapore General Hospital (SGH) for acute retention of urine (ARU) due to benign prostatic hypertrophy (BPH). From 1 June to 15 October 1997, 150 patients were admitted for ARU. Seventy-one patients were excluded from our study due to our exclusion criteria such as chronic retention, patients with bladder stones and cancer of the prostate. Our results showed that 58% (n = 46) had a successful trial off catheter. The risk factors for failure were: high residual urine (more than 800 ml) and high prostatic specific antigen (PSA) value (10.9 versus 21.5). All patients with normal PSA value (< 4 ng/l) had successful trial off catheters. There was no difference between trial off catheter 24 hours versus 48 hours after admission.

Acute Disease↗
PubMed1998

Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides.

The Salmonellae PhoP-PhoQ virulence regulators induce resistance to host cationic antimicrobial peptides (CAMP) after infection of vertebrate tissues, and Mg2+ or Ca2+ limitation. The PhoP-PhoQ activated gene, pagP, was identified as important to inducible CAMP resistance and increased acylation of lipid A, the major component of the outer leaflet of the outer membrane. pagP mutants demonstrated increased outer membrane permeability in response to CAMP, supporting the hypothesis that increased lipid A acylation is a CAMP resistance mechanism. Similarly, in response to Mg2+ limited growth, other enteric Gram-negative bacteria demonstrated increased lipid A acylation. Compounds that inhibit the ability to increase lipid A acylation may have utility as new antimicrobial agents.

Acylation↗
PubMed1998

PmrA-PmrB-regulated genes necessary for 4-aminoarabinose lipid A modification and polymyxin resistance.

Antimicrobial peptides are distributed throughout the animal kingdom and are a key component of innate immunity. Salmonella typhimurium regulates mechanisms of resistance to cationic antimicrobial peptides through the two-component systems PhoP-PhoQ and PmrA-PmrB. Polymyxin resistance is encoded by the PmrA-PmrB regulon, whose products modify the lipopolysaccharide (LPS) core and lipid A regions with ethanolamine and add aminoarabinose to the 4' phosphate of lipid A. Two PmrA-PmrB-regulated S. typhimurium loci (pmrE and pmrF) have been identified that are necessary for resistance to polymyxin and for the addition of aminoarabinose to lipid A. One locus, pmrE, contains a single gene previously identified as pagA (or ugd) that is predicted to encode a UDP-glucose dehydrogenase. The second locus, pmrF, is the second gene of a putative operon predicted to encode seven proteins, some with similarity to glycosyltransferases and other complex carbohydrate biosynthetic enzymes. Genes immediately flanking this putative operon are also regulated by PmrA-PmrB and/or have been associated with S. typhimurium polymyxin resistance. This work represents the first identification of non-regulatory genes necessary for modification of lipid A and subsequent antimicrobial peptide resistance, and provides support for the hypothesis that lipid A aminoarabinose modification promotes resistance to cationic antimicrobial peptides.

Anti-Bacterial Agents↗