Biomedical subjects

N S Lee

Publications and source records attributed to N S Lee.

At least 19 recordsLinked to original sources

PubMed2006

Corticotropin-releasing factor immunoreactivity increases in the cerebellar climbing fibers in the novel ataxic mutant mouse, pogo.

The ataxic pogo mouse (pogo/pogo) is a novel neurological mutant, which was derived as an inbred strain (KJR/MsKist) from a Korean wild mouse. The pathological manifestations include a difficulty in maintaining a normal posture, the failure of inter-limb coordination and an inability to walk straight. In this study, we examined the distribution of corticotropin-releasing factor (CRF) immunoreactive cerebellar climbing fibres and their projections to tyrosine hydroxylase (TH) immunoreactive Purkinje cells in the cerebellum of the pogo mutant mouse using immunohistochemistry. In the pogo/pogo mouse, a subset of climbing fibres was stained more intensely for CRF than in the control. Moreover, ataxic pogo mouse, neurons of the inferior olivary nucleus projecting climbing fibres were also more intensely stained for CRF than in the control. In the pogo/pogo mouse, TH immunoreactivity was located in the Purkinje cells, whereas no TH expression was found in the control. Double immunostaining for CRF and TH in the pogo/pogo cerebellum revealed that the distribution of TH-immunoreactive Purkinje cells corresponded to terminal fields of CRF-immunoreactive climbing fibres but not to the CRF-immunoreactive mossy fibres. Therefore, we suggest that an increase of CRF level may alter the function of targeted Purkinje cells and that it is related to the ataxic phenotype in the pogo mutant mouse.

Animals↗

PubMed2006

The absence of phosphorylated tyrosine hydroxylase expression in the purkinje cells of the ataxic mutant pogo mouse.

The pogo mouse is a new ataxic autosomal recessive mutant that arose in Korean wild mice (KJR/Mskist). Its ataxic phenotype includes difficulty in maintaining a normal posture and the inability to walk in a straight line. Several studies have reported that tyrosine hydroxylase (TH) is persistently ectopically expressed in particular subsets of Purkinje cells in a parasagittal banding pattern in several ataxic mutant mice, e.g. tottering alleles and pogo mice. In this present study, we examined the expression of an enzymatically active form of TH and phosphorylated TH at Ser(40) (phospho-TH) by using immunohistochemistry and double immunofluorescence in the cerebellum of pogo mice. TH immunostaining appeared in some Purkinje cells in pogo, but in only a few of Purkinje cells of their heterozygous littermate controls. In all groups of mice, no phospho-TH immunoreactive Purkinje cells were observed in the cerebellum, although subsets of TH immunoreactive Purkinje cells were found in adjacent sections. This study suggests that TH expression in the Purkinje cells of pogo abnormally increases without activation of this enzyme by phosphorylation. This may mean that TH in the Purkinje cells of these mutants does not catalyse the conversion of tyrosine to l-DOPA, and is not related to catecholamine synthesis.

Animals↗

PubMed2005

Post-natal changes of cyclin-dependent kinase 5 activator expression in the developing rat cerebellum.

cDNA of cyclin-dependent kinase 5 (Cdk5) was cloned based on its primary sequence homology to Cdc2 and Cdk2. Cdk5 requires the neuronal Cdk5 activators such as p35 or p39(nck5ai) (p39) for its activity. In this study, we examined post-natal changes in the p39 expression pattern during the development of the rat cerebellum. p39 began to express in somata and dendrites of Purkinje cells at post-natal day 3 (PD3). In particular, at PD12, parasagittal bands (stripes) with p39 immunoreactivity were weakly observed. At PD21, p39-immunoreactive stripes were developed when compared with the PD12 group. At this age stage, p39 immunoreactivity became weak in somata of Purkinje cells, not forming stripes. At PD28, a series of parasagittal bands were more distinct than those of the PD21 group, and p39 immunoreactivity disappeared in Purkinje cells, not forming p39 immunoreactive stripes. In the adults, p39 immunoreactivity in Purkinje cells was similar to that found in the PD28 group which showed that parasagittal bands were very narrow, and became progressively more slender. Therefore, we suggest that the post-natal changes of p39 expression in Purkinje cells in the cerebellum is an autonomous characteristic of Purkinje cells with a role of Cdk5 activators.

Animals↗

PubMed2005

Genetic association study of adiponectin polymorphisms with risk of Type 2 diabetes mellitus in Korean population.

AIMS: To investigate any association between Type 2 diabetes mellitus and two single nucleotide polymorphisms (SNPs) in the adiponectin gene, T45G and G276T, in the Korean population. METHODS: We genotyped 427 non-diabetic controls and 493 Type 2 diabetic patients for SNPs T45G and G276T of adiponectin gene, measured plasma adiponectin concentrations, and examined clinical parameters in Koreans. RESULTS: There were no statistically significant differences in allele frequencies of SNPs 45 and 276 comparing control with Type 2 diabetic subjects (T frequency 68.3% vs. 71.6%, P=0.13 for SNP45, G frequency 72.2% vs. 68.9%, P=0.12 for SNP276). The genotype distributions of these SNPs had no association with the risk of Type 2 diabetes and metabolic parameters of insulin resistance. Plasma levels of adiponectin were not statistically different according to T45G and G276T either, in both control and Type 2 diabetic subjects. CONCLUSION: The T45G and G276T of the adiponectin gene may not be an important determinant of Type 2 diabetes or insulin resistance in Korean subjects.

Adiponectin↗

PubMed2002

Intracellular ribozyme applications.

The exquisite target selectivity of trans -acting ribozymes has fostered their use as potential therapeutic agents and tools for down-regulating cellular transcripts. In living cells, free diffusion of RNAs is extremely limited, if it exists at all. Thus, getting ribozymes to base-pair with their cognate targets requires co-localizing the ribozyme transcript with the target RNA. In addition, not all sites along a given target RNA are equally accessible to ribozyme base pairing. Cellular proteins greatly influence the trafficking and structure of RNA, and therefore making ribozymes work effectively in cells a significant challenge. This article addresses the problems of getting engineered ribozymes to effectively pair with and cleave targets in cells. The work described here illuminates methods for target-site selection on native mRNAs, methods for ribozyme expression, and strategies for obtaining a discrete intracellular localization of ribozymes.

Blotting, Northern↗

PubMed2002

Morphological characteristics of C1 and C2 adrenergic neurone groups in marmoset monkey brainstem by using antibody against phenylethanolamine-N-methyltransferase.

This work describes a mapping study of phenylethanolamine-N-methyltransferase (PNMT) immunoreactive neurones and fibres in the medulla oblongata of the marmoset monkey, Callithrix jacchus. Two groups of PNMT-immunoreactive neurones were found in the marmoset monkey medulla oblongata: a ventrolateral (C1 group) and a dorsomedial PNMT-immunoreactive cells group (C2 group). The PNMT-immunoreactive cells in the ventrolateral group C1 were found to be located around the lateral reticular nucleus. The PNMT-immunoreactive somata within the ventrolateral medulla are round to oval, and mostly multipolar with branched processes. In the dorsomedial group C2, PNMT-immunoreactive cell bodies appeared near the obex. The majority of the dorsomedial PNMT-immunoreactive neurones were observed in the nucleus tractus solitarius; although some were present in the dorsal motor nucleus of the vagus. The PNMT-immunoreactive somata in the dorsomedial medulla were small and round or ovoid. These results provide information upon the adrenergic system in the medulla oblongata of a species that presents a useful model of a small primate brain, the marmoset monkey.

Adrenergic Fibers↗

PubMed2002

Characteristics of community-acquired methicillin-resistant Staphylococcus aureus in infants and children without known risk factors.

This retrospective study sought to determine the characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in patients younger than 18 years without known risk factors who were treated at a teaching hospital in central Taiwan. Epidemiological and clinical data were collected from medical charts. Possible risk factors included hospitalization within the past 6 months, transfer from other hospitals or nursing homes, and having underlying illness. A total of 173 isolates of community-acquired S. aureus were analyzed. Seventeen (9.8%) of these 173 isolates were methicillin-resistant S. aureus collected from patients without risk factors, 31 (17.9%) were methicillin-resistant S. aureus from patients with risk factors, and the other 125 (72.3%) were methicillin-susceptible S. aureus. Most isolates of community-acquired methicillin-resistant S. aureus collected from patients without risk factors (14/17, 82.4%) were obtained from the infected wounds of skin or soft tissues. Only 4 (23.5%) in 17 patients with isolates resistant to methicillin were prescribed antimicrobial therapy with glycopeptides. Nevertheless, all patients recovered without any long-term sequelae. These results highlight the fact that community-acquired methicillin-resistant S. aureus infections occur frequently in Taiwan among patients who have no established risk factors for this infection.

Adolescent↗

PubMed2001

Identification of structural domains affecting transactivation potential of Nm23.

The strong transactivation activity of the C-terminal half (amino acids 76-152) of Nm23 was reported previously. Here we examined a structural domain preventing or necessary to its transactivation activity. The C-terminal 1/4 (amino acids 109-152) was sufficient for transactivation, but the C-terminal half with a longer N-terminal extension (amino acids 58-152) caused the loss of the transactivation ability. Furthermore, coexpression of the N-terminal half with the C-terminus of Nm23-H1 blocked the transactivation activity of the C-terminal half, where direct interaction of both truncated proteins was demonstrated in vitro. Transactivation activities in the C-terminal halves of the known mutants (P96S, H118F, S120G, and S120A) exhibiting differential antimetastasis effects were also tested. Significant reduction of transactivation activity was observed only in H118F, indicating that NPD kinase active-site histidine is required. This suggests that transactivation potential of Nm23 is related to NDP kinase activity but not to metastasis suppressor activity.

Binding Sites↗

PubMed2001

Genome sequence of a VP2/NS junction region of pillar cell necrosis virus (PCNV) in cultured Japanese eel Anguilla japonica.

Pillar cell necrosis virus (PCNV) is an aquatic birnavirus that was isolated from farmed Japanese eel experiencing mass mortality. In this study, a VP2/NS junction region in genome segment A of PCNV was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) and sequenced. The VP2/NS region in PCNV had the highest homology with that of a strain Ab of infectious pancreatic necrosis virus (IPNV). This result revealed that PCNV belongs to birnavirus genogroup II.

Anguilla↗

PubMed2001

Functional colocalization of ribozymes and target mRNAs in Drosophila oocytes.

The effectiveness of catalytic RNAs (ribozymes) should be increased when they are colocalized to the same intracellular compartment as their RNA targets. We colocalized ribozymes with their mRNA targets in an animal model by using the discrete RNA localization signals present in the 3' untranslated regions (UTRs) of Drosophila bicoid and oskar mRNAs. These signals have been fused to a lacZ mRNA target and hammerhead ribozymes targeted against lacZ. Ribozyme efficacy was first assessed by an oligodeoxyribonucleotide-based assay to identify the most accessible sites for ribozyme interaction on native lacZ transcripts in ovary extracts. The most accessible sequence was used for the design and in vivo testing of a hammerhead ribozyme. When the ribozyme and target with synonymous 3' UTRs were expressed in the same ovaries, colocalization could be indirectly demonstrated by in situ hybridization. Colocalized ribozyme and target mRNAs resulted in a two- to threefold enhancement of ribozyme function compared with noncolocalized transcripts. This study provides the first demonstration of functional ribozyme target colocalization in an animal model.

3' Untranslated Regions↗

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

A case of jellyfish sting.

Jellyfish sting may result in a wide range of symptoms from common erythematous urticarial eruptions to the rare box-jelly induced acute respiratory failure. In Taiwan, with the increasing frequency of international travel, cases of jellyfish sting to foreigners are on the rise. We report a case of jellyfish sting with the rare presentation of painless contact dermatitis. A 38-y-o man accidentally stepped on a sea urchin with his right foot during scuba diving in a beach in Thailand. Traditional therapy with vinegar was applied on the lesion. However, when he returned to Taiwan, erythematous patches on the left thigh with linear radiations to the leg were discovered. The skin lesions had bizzare shapes and showed progressive change. No pain or numbness was noticed. Jellyfish stingwas suspected, topical medications were applied, and the patient recovered without complication. Jellyfish stings usually result in a painful erythematous eruption. In this case, though the lesion involved a large surface, there was no pain. Delayed diagnosis of jellyfish sting was due to the atypical presentation and the physician's unfamiliarity to the Thai jellyfish sting. Awareness to the wide spectrum of jellyfish sting symptoms should be promoted.

Adult↗

PubMed2000

Rev-binding aptamer and CMV promoter act as decoys to inhibit HIV replication.

We examined whether the antiviral effect of an HIV-1 Rev-binding aptamer [RBE(apt)] could be enhanced by a ribozyme directed against the HIV-1 env gene, and whether the antiviral activity was affected by different promoters. The efficacy of the aptamer and ribozyme DNAs was tested in HeLa cells co-transfected with the HIV-1 proviral clones, HXBDeltaBgl or pNL4-3, using transferrin-lipoplexes. The RBE(apt) and anti-env ribozyme genes were inserted into the pTZU6+27 plasmid, or constructed under the control of the human cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoters. The parental vector plasmids were used as controls. Co-transfection of the pTZU6+27 RBE(apt) plasmid with HXBDeltaBgl, or pNL4-3, at a weight ratio of 5:1, inhibited p24 production by 70 and 45%, respectively. The RSV RBE(apt) plasmid co-transfected with either HIV clone, at the same weight ratio, reduced viral production by 88%. The addition of the anti-env ribozyme to the RSV RBE(apt) did not enhance its antiviral activity. When the constructs were under the control of the CMV promoter, the expression of the HIV plasmids was very low and was independent of the presence of the RBE(apt). Thus, the effect of the RBE(apt) was strongly dependent on the promoter of the tested construct. The anti-HIV activity of the CMV RBE(apt) construct was non-specific, because co-transfection with either pCMV. SPORT-betagal or pCMVlacZ significantly suppressed HIV production from the HIV proviral clones. The reduction in p24 could not be attributed to the non-specific toxicity of the transfection procedure. Transfection of acutely HIV-infected HeLa-CD4 cells with pCMV.SPORT-betagal reduced the p24 level by 35%, while the expression of the U6 RBE(apt) did not affect p24 production. The suppression of HIV production from the HIV proviral clones by the CMV promoter constructs in the co-transfection assays may be explained by competition for transcription factors (TFs) between HIV and CMV promoters. This observation points to the potential for misleading results in co-transfections involving CMV constructs and HIV.

Anti-HIV Agents↗

PubMed2000

Seroprevalence of toxoplasmosis in the residents of Cheju island, Korea.

This study was performed to evaluate the epidemiological status of toxoplasmosis among the residents of Cheju island. The sera of local students from 18 high schools (boys 2110, girls 2460) and those of adults (474 admitted to Cheju Chungang General Hospital) were collected and checked for the IgG antibody titers against Toxoplasma gondii. Serum samples collected from both the students and adults showed sero-positive rate of 5.5% and 12.9%, respectively. Although the rates were not significantly different between the sexes (5.4% for the boys and 5.5% for the girls attending school), the geographical difference showed a significant difference between the urban (4.6-6.9%) and rural areas (5.6-8.8%) (p < 0.05). Based on the high positive rates, it should be necessary to control toxoplasmosis in Cheju island.

Adolescent↗

PubMed2000

Detection of IgG antibody against Neospora caninum in cattle in Korea.

A total of 492 cattle sera was screened by IgG-ELISA against Neospora caninum (Nc-1 strain and a Korean isolate, KBA-2) and Toxoplasma gondii. Out of 492, 113 sera (23.0%) reacted positively to either Nc-1 or KBA-2 strains of N. caninum. Among the 113 positive sera, 92 sera (81.4%) reacted with antigens of both strains, but 6 sera (5.3%) with Nc-1 and 15 sera (13.3%) with KBA-2 strain only. And with T. gondii antigen, 6 sera (1.2%) were positive but all reacted with N. caninum antigen also. Western blot revealed typical binding pattern according to ELISA values, such that high OD group reacted specifically to the major surface proteins including 43 kDa protein. Seroprevalence of 23.0% indicates that neosporosis seemed to be one of major causes of abortion in cattle. It is suggested here to establish more epidemiological researches nationwide systematically.

Animals↗

PubMed1999

Gill lamellar pillar cell necrosis, a new birnavirus disease in Japanese eels.

Since the late 1980s, a birnaviral gill disease has been occurring in Japanese eels Anguilla japonica reared in warmwater ponds in western regions in Japan. Diseased eels mostly displayed marked formations of aneurysmal hematomas within gill lamellae and high mortalities. Histological examination revealed necrosis of pillar cells and subsequent aggregation of erythrocytes inside the lamellar capillaries, and proliferation of interlamellar epithelia onto the lamellae. Gastric gland cells were also necrotized. Electron microscopy revealed birnavirus infection in lamellar pillar cells. The causative birnavirus was isolated and cultured in fish cell lines and was found to be related to an infectious pancreatic necrosis virus (IPNV) Sp serotype by neutralization tests. The viral pathogenicity was confirmed by the results of histopathological examinations and infectivity experiments.

Anguilla↗

PubMed1999

Size assessment of adenoid and nasopharyngeal airway by acoustic rhinometry in children.

Adenoid hypertrophy is known as the most common cause of nasal obstruction in children; thus, adenoidectomy with, or without, tonsillectomy is one of the most commonly performed surgical procedures in the paediatric population. Although many methods have been suggested, few studies have reported on how to assess adenoid size, pre-operatively. Acoustic rhinometry is an objective technique as well as a non-invasive method, which can be easily used in young children. This study confirmed that acoustic rhinometry is a non-invasive and objective technique for assessing the geometry of the nasal cavity and nasopharynx. Forty children were evaluated using symptomology, two different radiological measurements and acoustic rhinometry; the results were compared with endoscopic findings. Clinical symptoms and A/N ratio measured with Fujioka's method significantly correlated with the endoscopic assessment findings (r = 0.769 and 0.604 respectively). Significant increases in the cross-sectional area and volume of the nasopharynx were observed at the adenoid notch after adenoidectomy (p < 0.005 and p < 0.005, respectively). Acoustic rhinometry showed a high degree of correlation of which adenoid occupied the nasopharyngeal airway under endoscopic examination (r = 0.771). Thus, the study concluded that acoustic rhinometry can be as good an objective method for measuring adenoid sizes as endoscopy and can be used as one of the pre-operative examination tools for adenoidectomy.

Adenoids↗

PubMed1999

mRNA localization signals can enhance the intracellular effectiveness of hammerhead ribozymes.

Subcellular localization signals for several mRNAs are positioned in their 3' untranslated regions (UTR). We have utilized the human alpha- and beta-actin 3' UTRs as signals for colocalizing hammerhead ribozymes with a lacZtarget mRNA. Ribozyme and target genes containing matched or unmatched 3' UTRs were cotransfected into 12-day-old chicken embryonic myoblast and fibroblast (CEMF) cultures and assayed by in situ hybridization (ISH) using a dual label, antibody sandwich procedure, and dual fluorescence microscopy to monitor intracellular colocalization. Beta-galactosidase localization in transfectants was visualized by incubation with X-gal and also quantitated by an o-nitrophenyl beta-D-galactopyranoside (ONPG) assay. We found that the percentage of colocalization using the matched alpha- or beta-actin 3' UTR (alpha-alpha or beta-beta) was enhanced approximately threefold relative to unmatched 3' UTRs. The increase in ribozyme-mediated inhibition of beta-galactosidase activity observed when matched 3' UTRs were used was consistent with the observed percentage of colocalization. These results represent the first direct demonstration that mRNA localization signals (zipcodes) can be utilized to enhance intracellular ribozyme efficacy.

3' Untranslated Regions↗