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K K Lee

Publications and source records attributed to K K Lee.

At least 55 records · Page 3Linked to original sources
PubMed2001

BAF is required for emerin assembly into the reforming nuclear envelope.

Mutations in emerin cause the X-linked recessive form of Emery-Dreifuss muscular dystrophy (EDMD). Emerin localizes at the inner membrane of the nuclear envelope (NE) during interphase, and diffuses into the ER when the NE disassembles during mitosis. We analyzed the recruitment of wildtype and mutant GFP-tagged emerin proteins during nuclear envelope assembly in living HeLa cells. During telophase, emerin accumulates briefly at the 'core' region of telophase chromosomes, and later distributes over the entire nuclear rim. Barrier-to-autointegration factor (BAF), a protein that binds nonspecifically to double-stranded DNA in vitro, co-localized with emerin at the 'core' region of chromosomes during telophase. An emerin mutant defective for binding to BAF in vitro failed to localize at the 'core' in vivo, and subsequently failed to localize at the reformed NE. In HeLa cells that expressed BAF mutant G25E, which did not show 'core' localization, the endogenous emerin proteins failed to localize at the 'core' region during telophase, and did not assemble into the NE during the subsequent interphase. BAF mutant G25E also dominantly dislocalized LAP2beta and lamin A from the NE, but had no effect on the localization of lamin B. We conclude that BAF is required for the assembly of emerin and A-type lamins at the reforming NE during telophase, and may mediate their stability in the subsequent interphase.

Amino Acid Sequence↗
PubMed2001

A case of malignant proliferating trichilemmoma of the scalp with multiple metastases.

We report a case of malignant proliferating trichilemmal tumor showing multiple distant metastases. The patient demonstrated a round mass in the right occipital area for 12 months and the lesion grew rapidly to assume 8 x 6.5 x 4 cm in diameter, with areas of superficial erosion and crusting within the recent 3 months. The entire lesion was removed with a wide surgical excision. It recurred on the neck area 4 months after excision and the lesion was removed with surgical resection again. There was evidence of multiple metastases on CNS and mediastinal lymph nodes after 6 months. The patient was treated with cisplatin and etoposide combination chemotherapy and a partial response was achieved.

Adult↗
PubMed2001

Pathogenicity of Vibrio alginolyticus isolated from diseased small abalone Haliotis diversicolor supertexta.

Outbreaks of mass mortality among cultured small abalone Haliotis diversicolor supertexta with abscess/ulcers in the mantle occurred in 1998 at Kao-Hsiung, Taiwan. A swarming bacterium, strain H-11 was isolated from the haemolymph of the moribund small abalone using tryptic soy agar supplemented with 3% NaCl and/or thiosulphate citrate bile salt sucrose agar. This strain was characterized and identified as Vibrio alginolyticus on the basis of various biochemical tests. The H-11 strain and its extracellular products were virulent to small abalones with LD50 values of 3.6 x 10(5) colony forming units and 2.96 microg protein/g body weight, respectively.

Animals↗
PubMed2001

Endonasal endoscopic removal of growth-hormone-secreting pituitary adenomas.

Trans-sphenoidal removal of pituitary tumours using the endonasal endoscopic technique, a novel application, is herein reported in five consecutive patients with growth-hormone-secreting pituitary adenomas seen at a teaching hospital in Hong Kong. All five patients demonstrated complete tumour removal on postoperative imaging and hormonal assessment following the procedure. Surgical morbidity and symptoms were minimal; postoperative obstructive nasal packing was not required with this technique, which greatly improved patient comfort. Preliminary experience suggests that the endonasal endoscopic approach is a safe and effective alternative to the conventional trans-septal microscopic method for the treatment of pituitary tumour. A randomised controlled trial comparing these two approaches is currently underway at this institution.

Adenoma↗
PubMed2001

Galectin-3-mediated adherence of Proteus mirabilis to Madin-Darby canine kidney cells.

Proteus mirabilis is an important cause of urinary tract infections (UTIs) and can result in acute pyelonephritis. Proteus mirabilis expresses several, morphologically distinct, fimbrial species, and previous studies have shown that the nonagglutinating fimbriae (NAF) mediate bacterial adherence to a number of cell lines, including Madin-Darby canine kidney (MDCK) cells. Immunoblot overlay analysis of the plasma membrane fraction from MDCK cells with purified NAF revealed a 34-kDa band, which has been analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Database search identified galectin-3 as a potential protein candidate. Immunocytochemical assay of MDCK cells with a galectin-3-specific monoclonal antibody, anti-Mac-2, confirmed its presence on the plasma membrane extracellular surface. Preincubation of P. mirabilis with anti-Mac-2 monoclonal antibodies, specific for galectin-3, resulted in the inhibition of bacterial binding to MDCK cells. These data suggest a role for galectin-3, interacting with appropriately glycosylated surface receptors and P. mirabilis fimbriae, as a mediator of bacterial adherence in vitro.

Animals↗
PubMed2000

A novel epigenetic control operating on Vme1+ locus leads to variegated monoallelic expression.

Vme1, located near an imprinted region containing Peg1/Mest, Copg2, and Mit1/Lb9 on mouse chromosome 6, was identified and characterized to be under novel epigenetic regulations mediating nonimprinted monoallelic expression. The gene was transcribed independently from at least four promoters and alternatively spliced. Variable expression of the gene was found among individuals and was not affected by genetic backgrounds, in contrast to a relatively consistent expression of unlinked Peg3 under different genetic backgrounds. Monoallelic expression of the gene was confirmed in several tissues of hybrid F1s between a domesticus and a molossinus subspecies. The nature of monoallelic expression was different from those of its neighboring genes with respect to the allelic preference for the expression. The observed variable expression and monoallelic expression propose a mechanism that operates to variegate the Vme1 transcription acting asynchronously on parental alleles. In addition, we observed that some biallelically expressed tissues exhibited allele-specific splicing such that expression from one parental allele yields elongated splice variants, whereas the other allele is spliced into a short version. This unusual finding suggests that an epigenotype of the promoter can determine the splicing fate of the transcript.

Alleles↗
PubMed2000

Identification and purification of an intrinsic human muscle myogenic factor that enhances muscle repair and regeneration.

The limited ability of damaged muscle to regenerate after gross injuries is a major clinical problem. To date, there is no effective therapeutic treatment for muscle injuries. In the present study, we have examined the ability of crude and fractionated human skeletal muscle extracts to promote myogenic cell proliferation and differentiation. It was found that the crude muscle extract could significantly stimulate BrdU incorporation in C2C12 myogenic cell line. In addition, the extract also promoted myogenic cell alignment and fusion. Using electrophoresis techniques, in conjunction with in vitro refolding technique, a protein with molecular weight of approximately 40 kDa was identified that could produce the same effects as the crude muscle exdtract. We also tested the ability of semipurified (30-50 kDa) muscle extract to promote muscle repair in adult rats. Surgical intervention was used to induce muscle damage in the tibialis anterior. The semipurified muscle extract (fraction H) was injected subcutaneously over the tibialis anterior for a period of 5 days. It was found that the damaged muscle fibers were replaced by newly regenerated muscle fibers. These newly regenerated fibers originated from the fusion of differentiated satellite cells as revealed by BrdU-labeling analysis. In contrast, the injury site of muscles treated with BSA control protein contained mainly fibroblasts.

Adult↗
PubMed2000

Blastocyst viability and generation of transgenic cattle following freezing of in vitro produced, DNA-injected embryos.

This study examined whether the viability, determined in vitro, of DNA-injected bovine embryos produced in vitro was affected by freezing, and if the frozen embryos developed to term following transfer to recipients. In vitro fertilized zygotes were injected with the pBL1 gene and then co-cultured with mouse embryonic fibroblasts (MEF) in CR1aa medium. Embryos were prepared for cryopreservation by exposure to a 10% (v/v) glycerol solution, loaded into 0.25 ml straws and then frozen by conventional slow freezing. Thawing was by rapid warming in water (37 degrees C) and embryos were rehydrated in PBS diluents of 6%, 3% and 0% (v/v) glycerol supplemented with 0.25 M sucrose and 0.5% (w/v) BSA. In Experiment 1, blastocysts that developed from DNA-injected embryos were individually classified into three morphological groups and three stages of development prior to freezing. DNA-injected blastocysts of excellent quality at freezing showed a higher survival rate (78.8+/-10.6%) after thawing than those of good (60. 9+/-16.4%) or fair (12.5+/-5.9%) quality (P<0.05). Post-thaw survival rate, judged in vitro, increased with more advanced stage of blastocyst development at freezing (early 48.8+/-15.9%, mid 52. 1+/-12.6% and expanded 71.2+/-1.1; P<0.05). In Experiment 2, the frozen/thawed embryos were transferred to recipients to examine in vivo viability. Following transfer of one or two embryos per recipient, pregnancy rates at 60 days of gestation were 13.6% (13/96) for frozen embryos and 26.5% (43/162) for fresh embryos (P<0. 05). Of the 12 live calves born from the frozen/thawed embryos, two males (18.3%) were transgenic. None of the live-born calves derived from fresh embryos exhibited the transgene. One of transgenic bulls did not produce transgenic sperm. Three out of 23 calves (13.0%) produced from cows inseminated with semen of the other bull were transgenic, suggesting that this animal was a germ-line mosaic. These studies indicated that the viability of in vitro produced, DNA-injected bovine blastocysts was affected by freezing and by both the quality and stage of development of the embryo prior to freezing. The generation of transgenic cattle demonstrates that it is feasible to freeze DNA-injected, in vitro produced embryos.

Animals↗
PubMed2000

Effect of intravenous omeprazole on recurrent bleeding after endoscopic treatment of bleeding peptic ulcers.

BACKGROUND: After endoscopic treatment of bleeding peptic ulcers, bleeding recurs in 15 to 20 percent of patients. METHODS: We assessed whether the use of a high dose of a proton-pump inhibitor would reduce the frequency of recurrent bleeding after endoscopic treatment of bleeding peptic ulcers. Patients with actively bleeding ulcers or ulcers with nonbleeding visible vessels were treated with an epinephrine injection followed by thermocoagulation. After hemostasis had been achieved, they were randomly assigned in a double-blind fashion to receive omeprazole (given as a bolus intravenous injection of 80 mg followed by an infusion of 8 mg per hour for 72 hours) or placebo. After the infusion, all patients were given 20 mg of omeprazole orally per day for eight weeks. The primary end point was recurrent bleeding within 30 days after endoscopy. RESULTS: We enrolled 240 patients, 120 in each group. Bleeding recurred within 30 days in 8 patients (6.7 percent) in the omeprazole group, as compared with 27 (22.5 percent) in the placebo group (hazard ratio, 3.9; 95 percent confidence interval, 1.7 to 9.0). Most episodes of recurrent bleeding occurred during the first three days, which made up the infusion period (5 in the omeprazole group and 24 in the placebo group, P<0.001). Three patients in the omeprazole group and nine in the placebo group underwent surgery (P=0.14). Five patients (4.2 percent) in the omeprazole group and 12 (10 percent) in the placebo group died within 30 days after endoscopy (P=0.13). CONCLUSIONS: After endoscopic treatment of bleeding peptic ulcers, a high-dose infusion of omeprazole substantially reduces the risk of recurrent bleeding.

Aged↗
PubMed2000

Outcome and quality of life of patients with acute pancreatitis requiring intensive care.

BACKGROUND: Patients with severe acute pancreatitis often require intensive care unit (ICU) admission, have multiple complications, spend weeks to months in the hospital, and consume a large amount of resources. The aim of this study was to evaluate the ICU course, costs, mortality, and quality of life of patients who require ICU admission for acute pancreatitis. METHODS: Patients with acute pancreatitis requiring ICU admission were identified retrospectively. Data regarding in-hospital morbidity, mortality, and hospital costs were obtained. Long-term quality of life was assessed using the Short Form-36 Health Survey (SF-36). RESULTS: Fifty-two patients were identified. There were 31 men and 21 women: the mean age was 53 years (range, 22-89). The most common causes of acute pancreatitis were gallstones (44%) and alcoholism (17%). Pulmonary failure (52% required mechanical ventilation) and renal failure (21% required dialysis) were common. There were 39 (75%) hospital survivors and 13 (25%) nonsurvivors. In the first 24 h, the mean Acute Physiology and Chronic Health Evaluation (APACHE) II scores were 10 +/- 6 in survivors and 16 +/- 4 in the nonsurvivors (<0.01). Mean length of ICU (15 +/- 18 and 28 +/- 31 days) and hospital (40 +/- 34 and 38 +/- 34 days) stays were similar in survivors and nonsurvivors, respectively (NS). The mean hospital cost for survivors was $83,611 +/- 88,434 and that for nonsurvivors was $136,730 +/- 95,045 (P = 0. 09). The estimated cost to obtain one hospital survivor was $129,188. Of the 39 hospital survivors, 5 died later, 21 completed the SF-36, and 13 were lost to follow-up. Long-term quality of life (SF-36) was similar to that of an age-matched population. Twenty of twenty-one felt their general health was at least as good as it had been 1 year previously. CONCLUSIONS: Patients with severe acute pancreatitis need prolonged ICU and hospital stays. APACHE II may be a good predictor of outcome; further, prospective evaluation is needed. Although resource utilization is high, most patients survive and have good long-term quality of life.

APACHE↗
PubMed2000

Improved development of DNA-injected bovine embryos co-cultured with mouse embryonic fibroblast cells.

The in vitro development of DNA-injected bovine zygotes, produced in vitro, was compared when cultured with or without mouse embryonic fibroblasts (MEF). The in vivo viability of the embryos produced in these in vitro culture systems was assessed by single or double transfer to recipients taken to term. For these experiments, in vitro fertilized oocytes were not injected (Experiment 1) or were injected with pBL1 gene (Experiment 2) and then cultured for 2 days in CR1aa medium supplemented with 3 mg/ml BSA at 38.5 degrees C in a humidified atmosphere of 5% CO(2) in air. Embryos that developed to the 4- to 8-cell stage at the end of this period were randomly assigned to the two cultured systems and cultured for a further 5 days in groups of 10 to 15 embryos in 0.75 ml medium. These two culture systems were CR1aa medium alone or co-culture with MEF in CR1aa medium supplemented with 10% fetal bovine serum (FBS). Every 48 h, 0.5 ml of the medium was replaced with fresh CR1aa medium and at Day 5 of culture, both media were supplemented by the addition of 5.56 mM glucose and 1x GMS-X supplement solutions. Results were assessed as morphological development of the embryos and data were analyzed by Chi-square test or Student's t-test. The development rate of in vitro fertilization (IVF)-derived embryos co-cultured with MEF (24.4%, 49/201) was significantly higher than those cultured alone (14.4%, 28/194; P<0.05) in Experiment 1. There was a similar difference between the treatments in the proportions of embryos which reached the hatching stage or hatched (10.9%, 22/201 vs. 4.1%, 8/194, respectively; P<0.05). DNA-injected embryos co-cultured with MEF (13.7%, 28/205) showed a higher developmental rate than that of the embryos cultured without MEF (6.7%, 13/193; P<0.05) in Experiment 2. Following the transfer to recipients of one or two DNA-injected blastocysts, the pregnancy rates for two culture systems were similar (MEF co-culture 27.4%, 23/84; CR1aa culture 24. 2%, 16/66). However, the numbers of calves born alive from these pregnancies were higher on the MEF co-culture group (82.6%, 19/23) than the CR1aa culture group (56.2%, 9/16). It was concluded that in vitro embryo development to the blastocyst stage and subsequent in vivo development to term of DNA-injected bovine embryos was improved in comparison to culture in CR1aa alone when the last 5 days of in vitro culture were in a MEF co-culture system.

Animals↗
PubMed2000

Molecular cloning and characterization of the mouse peroxiredoxin V gene.

We have cloned two cDNA isoforms as well as genomic sequences of the mouse Prx V gene and characterized their molecular genetic features. Two isoforms of the mouse Prx V cDNA were identified from liver and testis. The testis-originated long transcripts had extra 1164-bp 5'-UTR sequences compared to the liver-originated short transcripts. Primer extension and sequence analyses revealed that the two isoforms were presumably transcribed at the same gene locus. The gene was composed of six exons spanning 3.2 kb. The short transcript was abundantly expressed in the kidney, liver, and heart of the adult mouse tissues and in the extra-membrane of the 10.5 dpc embryos. The long transcript of 1985 bp was abundantly detected in testis with trace amounts in other tissues. Interestingly, in testis and fetus, only mRNA expression of the long form was identified. However, the protein expression was not found in testis, implying that the long form could not properly direct the protein expression. The long Prx V cDNA has eight uORFs in the extra 5'-UTR, which proceed the major ORF. The inability of protein expression for the long-form cDNA in testis suggests that the uORFs might inhibit translation of the major ORF and thereby confer the tissue-specific regulation of the mouse Prx V gene.

5' Untranslated Regions↗
PubMed2000

Bmp-4 requires the presence of the digits to initiate programmed cell death in limb interdigital tissues.

The effects of Bmp-4 on interdigital cell death were investigated in the mouse. Affi-Gel beads, loaded with recombinant Bmp-4 protein, were transplanted into the interdigital tissues of day 12.5 hindlimb, ex utero. It was established that Bmp-4 could induce precocious interdigital cell death. Using in situ hybridization, the expression patterns of bmp-4 and alk-6 receptor were established. Both genes were found coexpressed in the interdigital region of 12.5- and 13. 5-day hindlimbs. This suggests that Bmp-4 may act in an autocrine fashion. We have also studied the effects of Bmp-4 on 12.5-day interdigital tissue cultures. In all specimens examined, the interdigital tissues produced cartilage instead of participating in cell death. The addition of exogenous Bmp-4 to the interdigital cultures did not induce apoptosis but instead enhanced chondrogenesis. The discrepancy between the effects of Bmp-4 in vitro and ex utero was attributed to the presence of digits. When a flanking digit was left attached to the interdigital tissues, in vitro, Bmp-4 promoted apoptosis instead of chondrogenesis. In sum, the results suggest that Bmp-4 is a multifunctional protein and its effect on the interdigital tissues is dependent on the modulating influence of the digits.

Activin Receptors↗
PubMed2000

Effect of short interspersed element sequences on the integration and expression of a reporter gene in the preimplantation-stage mouse embryos.

Based on the assumption that foreign DNA sequences may have increased chance of integration into the host genome if they are flanked by high copy-numbered genomic sequences such as SINEs (short interspersed elements), we investigated the integration frequency of Lac Z reporter gene flanked by a fused B1/B2 in an in vivo system using pronuclear microinjection technique in the mouse. The SINE-flanked DNA showed a 4-fold increased integration frequency of the reporter gene than the control DNA (63% vs. 16%). Moreover, the level of beta-galactosidase expression, estimated from the X-Gal staining intensity in transgenic embryos, was greatly higher in SINE-carrying DNA. These results suggest that the SINE sequences can serve a very useful tool in improving the efficiency of current transgenic animal technology.

Animals↗
PubMed2000

Potent and stage-specific action of glutathione on the development of goat early embryos in vitro.

The effect of glutathione (GSH) addition on the development of 1- or 2-cell goat early embryos in vitro was examined. Embryos were collected from superovulated Korean black goat (Capra hircus aegagrus) and cultured for 6 days in synthetic oviduct fluid medium supplemented with either bovine serum albumin (BSA) or serum. Without GSH addition, almost all embryos could not develop beyond 8- to 16-cell block. However, GSH addition greatly improved in vitro development of early embryos to blastocyst stage, and its action was highly dependent on the presence and source of proteins supplemented into the culture medium. Among the protein-supplemented cultures, GSH effect was most prominent in 10% FBS-supplemented culture, in which the proportion (91%) of blastocysts developed from early embryos was much higher than that of BSA- (42-64% depending on its content) or goat serum (GS)-supplemented cultures (21%), or even than that of somatic cell-supported co-culture (60%). As well as in terms of the morphological development, mean cell number of blastocysts (185 +/- 12) developed from FBS condition was significantly higher than that of blastocysts developed from any other culture conditions and moreover comparable to that of blastocysts developed in vivo (190 +/- 9). The viability of these blastocysts was finally confirmed by their term development (6/12) from embryo transfer. To delineate action time of GSH during embryo development, GSH was treated at 1-day intervals through 6-days culture periods excepting the last day. In the GSH-treated embryos at day 3 of culture, which corresponds to the time of in vitro 8- to 16-cell block stage, the proportion of blastocyst was markedly increased up to 77% of cultured embryos and conversely that of the arrested embryos was decreased to 7%. In the embryos treated later, however, their developmental potency decreased abruptly. Therefore, these results clearly demonstrated that GSH could greatly improve the in vitro development of goat early embryos by specifically acting on the 8- to 16-cell block stage during in vitro development, suggesting that GSH may be one of the important regulators on the development of goat embryos in vivo.

Animals↗
PubMed2000

Hairy cell leukemia in Hong Kong Chinese: a 12-year retrospective survey.

BACKGROUND: Hairy cell leukemia (HCL) is a unique chronic B cell lymphoproliferative disease (B-LPD), with distinct clinical and pathological features, and excellent treatment response to 2-chlorodeoxyadenosine (2-CDA) and pentostatin. There have been few reports of HCL from oriental countries. PATIENTS AND METHODS: A retrospective survey of HCL in six major hematology units in Hong Kong over a 12-year period. RESULTS: There were 18 cases of HCL identified. Most patients presented with fever, splenomegaly and monocytopenia. Lymphadenopathy was present in three patients, and open biopsy revealed tuberculosis infection in two cases. Seven cases received interferon and 12 cases received 2-CDA. Four patients died from bronchogenic carcinoma, cerebral vascular accident, fulminant hepatitis B virus reactivation and malignant melanoma. The remaining 14 patients are in clinical remission at a median of 6 years' follow-up; two are also surviving from second malignancies (thyroid papillary carcinoma and renal cell carcinoma). CONCLUSIONS: Parallel to the low incidence of B-LPD in Chinese, the incidence of HCL (0.035/100000 population per year) is much lower than in Western series. Other clinical features such as male dominance, clinical presentation, response to 2-CDA treatment, and association with second malignancy are similar to Western reports. However, two common complications in the Chinese population are the fulminant reactivation of hepatitis B infection and disseminated tuberculosis infection.

Adult↗
PubMed2000

Neurotransmitters, neuropeptides and calcium binding proteins in developing human cerebellum: a review.

Many endogenous neurochemicals that are known to have important functions in the mature central nervous system have also been found in the developing human cerebellum. Cholinergic neurons, as revealed by immunoreactivities towards choline acetyltransferase or acetylcholinesterase, appear early at 23 weeks of gestation in the cerebellar cortex and deep nuclei. Immunoreactivities gradually increase until the first postnatal month. Enkephalin is localized in the developing cerebellum, initially in the fibers of the cortex and deep nuclei at 16-20 weeks and then also in the Purkinje cells, granule cells, basket cells and Golgi cells at 23 weeks onward. Another neuropeptide, substance P, is localized mainly in the fibers of the dentate nucleus from 9 to 24 weeks but substance P immunoreactivity declines thereafter. GABA, an inhibitory neurotransmitter of the central nervous system, starts to appear at 16 weeks in the Purkinje cells, stellate cells, basket cells, mossy fibers and neurons of deep nuclei. GABA expression is gradually upregulated toward term forming networks of GABA-positive fibers and neurons. Catecholaminergic fibers and neurons are also detected in the cortex and deep nuclei at as early as 16 weeks. Calcium binding proteins, calbindin D28K and parvalbumin, make their first appearance in the cortex and deep nuclei at 14 weeks and then their expression decreases toward term, while calretinin appears later at 21 weeks but its expression increases with fetal age. The above findings suggest that many neurotransmitters, neuropeptides and calcium binding proteins (1) appear early during development of the cerebellum; (2) have specific temporal and spatial expression patterns; (3) may have functions other than those found in the mature neural systems; and (4) may be able to interact with each other during early development.

Animals↗