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Biomedical subjects

H Yoon

Publications and source records attributed to H Yoon.

At least 19 recordsLinked to original sources
PubMed2006

Botulinum toxin A for the management of vulvodynia.

Clinically, botulinum toxin A blocks the cholinergic innervation of the target tissue. Recently, it has been proved effective not only at a neuromuscular junction but also within parasympathetic or sympathetic neural synapses. Seven women with pain on genitalia that could not be controlled with conventional pain managements were enrolled in this study. Twenty to 40 U of botulinum toxin A were used in each injection. Injection sites were the vestibule, levator ani muscle or the perineal body. Repeat injections were administered every 2 weeks if the patient's symptoms had not fully subsided. In all patients, pain had disappeared with botulinum toxin A injections. Five patients needed to be injected twice; the other two patients needed only one injection. We did not observe complications related to botulinum toxin A injections, such as pain, hemorrhage, infection, muscle paralysis or other complications. The subjective pain score improved from 8.3 to 1.4, and no one has experienced a recurrence (the follow-up period was four to 24 months, with a mean follow-up of 11.6 months). Botulinum toxin A is effective in blocking nociception. Even though further investigation and well-controlled study will be necessary, we suggest that the botulinum toxin therapy would be useful and safe in managing vulvodynia of muscular or neuroinflammatory origins.

Adult↗
PubMed2006

Simulation analyses to evaluate alternative control strategies for the 2002 foot-and-mouth disease outbreak in the Republic of Korea.

Using the stochastic and spatial simulation model of between-farm spread of disease, InterSpread Plus, we evaluated the effect of alternative strategies for controlling the 2002 epidemic of foot-and-mouth disease (FMD) in the Republic of Korea. InterSpread Plus was parameterised to simulate epidemics of FMD in the population of farms containing susceptible animal species in the Korean counties of Yongin, Icheon, Pyongtaek, Anseong, Eumseong, Asan, Cheonan, and Jincheon. The starting point of our analyses was the simulation of a reference strategy, which approximated the real epidemic. The results of simulations of alternative epidemic-control strategies were compared with this reference strategy. Ring vaccination (when used with either limited or extended pre-emptive depopulation) reduced both the size and variability of the predicted number of infected farms. Reducing the time between disease incursion and commencement of controls had the greatest effect on reducing the predicted number of infected farms.

Animals↗
PubMed2005

Virus spread pattern within infected chicken farms using regression model: the 2003-2004 HPAI epidemic in the Republic of Korea.

During the 2003-2004 epidemic in Korea, the infection time and within-farm spread pattern of virus were analysed for the highly pathogenic avian influenza (HPAI) outbreak on chicken farms using regression models based on epidemiological data. Mortality observed on a given day had a positive linear association with time after initial infection. HPAI spread more rapidly on farms managed by employees and on farms with larger numbers of chicken houses in use. The disease spread more rapidly among layer chickens than among broilers. Using statistical model, we found that farmers recognize the abnormally high mortality resulting from HPAI approximately 5 days after infection. Without any intervention, entire flocks would die within 12 days of introduction of the HPAI virus to the infected farm.

Animal Husbandry↗
PubMed2004

Overexpression of LIM kinase 1 renders resistance to apoptosis in PC12 cells by inhibition of caspase activation.

LIM kinases (LIMKs) regulate actin polymerization by phosphorylating cofilin and are predominantly expressed in neural tissue. In this study, the effect of LIMK1 overexpression in PC12 cell apoptosis was investigated. PC12 cells overexpressing the wild-type LIMK1 were more resistant to serum-withdrawal-induced cell death and the level of caspase 3 activation in these cells was lower than in the control PC12 cells or than in the PC12 cells expressing a mutant LIMK1 lacking the kinase domain. The inhibition of JNK activation was observed in the PC12 cells overexpressing the wild-type LIMK1 after serum withdrawal. These results suggest that the LIMK1 might allow resistance to apoptosis in PC12 cells by inhibiting JNK activation.

Actin Cytoskeleton↗
PubMed2004

Erythrocyte ghost-mediated gene delivery for prolonged and blood-targeted expression.

This study reports the use of erythrocyte ghosts (EG) as a biocompatible nonviral delivery system for extended circulation and prolonged expression of plasmid DNA in the blood. Murine interleukin-2-expressing plasmid DNA was efficiently loaded to EG by electroporation in hypotonic condition. The presence of plasmid DNA in EG was confirmed by fluorescence-labeled plasmid DNA. At 21 min after intravenous administration into mice, the level of plasmid DNA in the blood was 92 000-fold higher following EG-mediated delivery as compared to the injection of naked form. EG-mediated gene delivery revealed higher and more prolonged mRNA expression levels of plasmid DNA in the blood until 9 days after the single intravenous injection. Moreover, plasmid DNA-loaded EG showed gene expression targeted to the blood cells. At 3 days post-dose, substantial expression levels of plasmid DNA delivered in EG were observed only in the blood and not in the other organs. Of the blood cells, the subpopulation containing granulocytes showed higher expression of plasmid DNA than mononuclear cells. These results indicate the potential of EG as a safe, prolonged and blood-targeted delivery system of therapeutic genes.

Animals↗
PubMed2001

Population coding in neuronal systems with correlated noise.

Neuronal representations of external events are often distributed across large populations of cells. We study the effect of correlated noise on the accuracy of these neuronal population codes. Our main question is whether the inherent error in the population code can be suppressed by increasing the size of the population N in the presence of correlated noise. We address this issue using a model of a population of neurons that are broadly tuned to an angular variable in two dimensions. The fluctuations in the neuronal activities are modeled as Gaussian noises with pairwise correlations that decay exponentially with the difference between the preferred angles of the correlated cells. We assume that the system is broadly tuned, which means that both the correlation length and the width of the tuning curves of the mean responses span a substantial fraction of the entire system length. The performance of the system is measured by the Fisher information (FI), which bounds its estimation error. By calculating the FI in the limit of a large N, we show that positive correlations decrease the estimation capability of the network, relative to the uncorrelated population. The information capacity saturates to a finite value as the number of cells in the population grows. In contrast, negative correlations substantially increase the information capacity of the neuronal population. These results are supplemented by the effect of correlations on the mutual information of the system. Our analysis provides an estimate of the effective number of statistically independent degrees of freedom, denoted N(eff), that a large correlated system can have. According to our theory N(eff) remains finite in the limit of a large N. Estimating the parameters of the correlations and tuning curves from experimental data in some cortical areas that code for angles, we predict that the number of effective degrees of freedom embedded in localized populations in these areas is less than or of the order of approximately 10(2).

Animals↗
PubMed2001

Differential effects of primary human immunodeficiency virus type 1 nef sequences on downregulation of CD4 and MHC class I.

We analyzed two primary nef sequences, KS2 (subtype B) and K306 (subtype D), each directly isolated from patients. Cell lines constitutively expressing respective Nef proteins were constructed using a retroviral vector. There were significant differences in the ability to downregulate surface CD4 and MHC class I proteins between different nef sequences. When the nef sequence from NL432 was used as a reference, KS2 Nef demonstrated the highest ability to downregulate MHC class I, whereas it appeared to lack the ability to downregulate CD4. On the contrary, Nef from K306 decreased the level of surface CD4 to a greater extent, but was less effective on downregulation of MHC class I. These results showed that the levels of downregulation of CD4 and MHC class I could significantly vary among HIV strains and that two well-known functions of Nef, downregulation of CD4 and MHC class I, would be separated.

Base Sequence↗
PubMed2001

Prolonged organ retention and safety of plasmid DNA administered in polyethylenimine complexes.

Polyethylenimine (PEI) has been studied as an efficient nonviral gene transfer vector. Here, we report the biodistribution fates and safety of plasmid DNA intravenously administered in PEI complexes. Using pCMVbeta as a model gene, the biodistribution of plasmid DNA was measured by quantitative polymerase chain reaction. A deletion mutant of pCMVbeta was used as an internal standard. After intravenous administration of PEI/DNA complexes, the serum levels of DNA rapidly declined for up to 15 min. However, after this point, the serum levels of DNA diminished slowly. At 15 min after dose, PEI/DNA complexes showed 33-fold higher distribution of DNA in the lung than did naked DNA. At 24 h, all the organs tested showed much higher levels of plasmid DNA in PEI/DNA complexes, with distribution in the liver and lung being three orders of magnitude higher than naked DNA. The mRNA expression of DNA was observed in various organs of PEI/DNA-treated mice at 12 days after dose. Once a week dosing of PEI/DNA complexes over 3 consecutive weeks did not alter the histology of the organs. However, twice a week dosing over 3 weeks induced a sign of inflammation in the liver. These results indicate that PEI enhances the delivery and retention of plasmid DNA in the organs, especially the liver, but that safe delivery requires proper dosing intervals.

Animals↗
PubMed2001

APACC, a French prospective study on aspirin efficacy in reducing colorectal adenoma recurrence: design and baseline findings.

UNLABELLED: Colorectal cancer is the second most frequent cause of death from cancer in western countries. Many lines of evidence suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may offer chemoprevention against colorectal cancer. A multicentre, double-blind, randomized, controlled trial is underway to determine the efficacy of regular aspirin intake (160 or 300 mg/day) in reducing colorectal adenoma recurrence. We now report the baseline characteristics of subjects enrolled into the trial. RESULTS: A total of 618 polyps were excised from 274 patients at the baseline colonoscopy. Men had on average (+/-SD) 2.5 +/- 1.8 polyps per subject and women had 1.7 +/- 1.2. Ninety-one (33.7%) had three or more adenomas and 183 (67.8%) had more than one adenoma measuring 10 mm or more in diameter. The mean (+/-SD) age of the subjects was 57.7 (+/- 9.4) years. Sixty-seven (24.9%) reported that they had previously had adenoma(s), 95 (35.2%) reported a family history of colorectal cancer and 41 (15.2%) a family history of colorectal adenomas. PERSPECTIVE: All subjects will undergo a one-year clearance colonoscopy by February 2001. Clinical, molecular biological and dietary data will enable us to investigate other factors influencing the recurrence of adenomas in this group of high-risk subjects.

Adenoma↗
PubMed2001

Mouse MCT3 gene is expressed preferentially in retinal pigment and choroid plexus epithelia.

Monocarboxylate transporters (MCTs) are a family of highly homologous membrane proteins that mediate the 1:1 transport of a proton and a lactate ion. In chicken, MCT3 is preferentially expressed in the retinal pigment epithelium (RPE). We have isolated the mouse MCT3 cDNA and gene and characterized the pattern of tissue expression. MCT3 is a single copy gene with a 1.8-kb transcript that encodes a protein with a predicted molecular mass of 51.5 kDa. Based on Northern hybridization analysis, MCT3 transcript was expressed in only two tissues: RPE and choroid plexus epithelium (CPE). The choroid plexus forms a barrier between the cerebrospinal fluid and fenestrated capillaries, similar to the organization of the RPE and choroidal vessels. Immunohistochemical staining demonstrated that MCT3 was restricted to the basolateral membranes of both epithelia but was more abundant in RPE than CPE. Differences in the level of protein expression were confirmed by Western blot analysis. The cloning of MCT3 identifies a specific transporter that could regulate lactate levels in fluid-bathing neuronal tissues.

5' Untranslated Regions↗
PubMed2000

Pepsin-mediated processing of the cytoplasmic histone H2A to strong antimicrobial peptide buforin I.

The intestinal epithelium forms a first line of innate host defense by secretion of proteins with antimicrobial activity against microbial infection. Despite the extensive studies on the antimicrobial host defense in many gastrointestinal tracts, little is known about the antimicrobial defense system of the stomach. The potent antimicrobial peptide buforin I, consisting of 39 aa, was isolated recently from the stomach tissue of an Asian toad, Bufo bufo gargarizans. In this study we examined the mechanism of buforin I production in toad stomach tissue. Buforin I is produced by the action of pepsin isozymes, named pepsin Ca and Cb, cleaving the Tyr39-Ala40 bond of histone H2A. Immunohistochemical analysis revealed that buforin I is present extracellularly on the mucosal surface, and unacetylated histone H2A, a precursor of buforin I, is localized in the cytoplasm of gastric gland cells. Furthermore, Western blot analysis showed that buforin I is also present in the gastric fluids, and immunoelectron microscopy detected localization of the unacetylated histone H2A in the cytoplasmic granules of gastric gland cells. The distinct subcellular distribution of the unacetylated histone H2A and the detection of the unacetylated buforin I both on the mucosal surface and in the lumen suggest that buforin I is produced from the cytoplasmic unacetylated histone H2A secreted into the gastric lumen and subsequently processed by pepsins. Our results indicate that buforin I along with pepsins in the vertebrate stomach may contribute to the innate host defense of the stomach against invading microorganisms.

Amino Acid Sequence↗
PubMed2000

Crystallization and preliminary X-ray crystallographic analysis of NADPH: azodicarbonyl/quinone oxidoreductase, a plant zeta-crystallin.

Arabidopsis thaliana P1 protein was crystallized using the hanging drop vapor-diffusion method in 0.1 M piperazine-1, 4-bis(2-ethanesulfonic acid) buffer, containing 14% polyethylene glycol 6000 and 0.2 M magnesium acetate at pH 6.5 and 20 degrees C. The crystals are orthorhombic and belong to the space group P2(1)2(1)2(1) with unit cell dimensions of a=49.8, b=122.4 and c=149. 9 A. The diffraction data up to 2.9 A were collected by a multiwire area detector.

Alkanesulfonic Acids↗
PubMed2000

Nutritional intakes of vegetarian populations in France.

OBJECTIVE: To assess food behaviour and determine nutritional intakes of various vegetarian populations in France. DESIGN: A five-day self-administered food record which was mailed to members of the three principal French vegetarian organisations. SUBJECTS: 145 subjects, aged 7-87 y; 94 classical vegetarians (19% of those contacted), 34 Hindu lactovegetarians (17% of those contacted) and 17 macrobiotic (34% of those contacted). SETTING: The survey was conducted between March 1997 and July 1997 in France. RESULTS: Vegetarianism in France is represented by three main classes of food behaviour: ovolactovegetarian (AAV), lactovegetarian (KRI) and macrobiotic (MMK). The geometric mean intakes ranged from 1952 kcal/d (KRI), 2051 kcal/d (MMK) to 2384 kcal/d (AAV) for males and from 1302 kcal/d (MMK), 1675 kcal/d (AAV) to 1804 kcal/d (KRI) for females, after adjusting for age and BMI. The energy consumption in the MMK group was significantly lower than that in the AAV (P<0.05) and KRI groups (P<0.01), respectively. A difference among groups was observed for females (P=0.0002), but not for males. The MMK group consumed less lipid than the other two vegetarian groups, 46 g/d for men and 38 g/d for women vs 80 g/d for men and 61 g/d for women in the AAV group and 93 g/d for men and 81 g/d for women in the KRI group, respectively. Differences with AAV and MMK were statistically significant (P<0.001 for men and women for both groups). Mean protein consumption ranged from 60 g/d (AAV), 64 g/d (KRI) to 77 g/d (MMK) for males and from 46 g/d (MMK), 50 g/d (AAV) to 58 g/d (KRI) for females. Mean carbohydrate intakes ranged from 247 g/d (AAV), 321 g/d (KRI) to 338 g/d (MMK) in males and from 209 g/d (MMK), 228 g/d (AAV) to 242 g/d (KRI) in females. There were no significant differences in protein and carbohydrate intakes between the groups. Median calcium intakes ranged from 758.2 mg/d (MMK), 863 mg/d (AAV) to 989.3 mg/d (KRI) for the men and from 500.8 mg/d (MMK), 863 mg/d (AAV) to 934 mg/d (KRI) for the women. In the men, there was no differences in daily calcium intakes between the three vegetarian groups. However, we found a significant difference for women (P=0. 0041). The women in the MMK group presented significantly lower daily calcium intakes than the women in the AAV (P=0.013) and KRI (P=0.0032) groups. The AAV and KRI groups consumed dairy products supplying respectively 36% and 53% for the men and 39% and 59% for the women of total calcium against 0% for men and women in the MMK group. Median iron intakes ranged between 12.5 mg/d (KRI), 13.2 mg/d (AAV) and 22.5 mg/d (MMK) for the men and between 11.2 mg/d (KRI), 14.6 mg/d (AAV) and 16.9 mg/d (MMK) for the women. MMK (men P=0.0172 and women P=0.0131) and AAV (only in men P=0.037) groups consumed significantly higher quantities of iron than did the KRI group. The heme iron median intake in males and females of the three vegetarian groups was very low (<0.5%). Overall, the female vegetarians consumed 58.1 (MMK), 109 (AAV) and 127.4 (KRI) mg of vitamin C per day and the males 76.3 (MMK), 150.4 (AAV) and 150.4 (KRI) mg per day. Median vitamin B9 intakes ranged from 247.5 microg/d (KRI), 312 microg/d (MMK) to 390.4 microg/d (AAV) for the men and from 188.3 microg/d (MMK), 266.9 microg/d (KRI) to 323.8 microg/d (AAV) for the women. Vitamin B12 consumption ranged from 0.2 microg/d (MMK), 1.5 microg/d (AAV) to 1.7 microg/d (KRI) in the women and from 0.6 microg/d (MMK) to 1.0 microg/d (AAV and KRI) in the men. No differences in consumption were observed in the males. On the other hand, the women in the MMK group consumed significantly less vitamin C and B12 than did the women in the AAV (P=0.0006) and KRI (P=0. 0396) groups, while it was at the limit of significance for the females (P=0.0715) for vitamin B9. CONCLUSION: Our results suggest that vegetarians have a better understanding of dietary requirements than does the general population. (ABSTRACT TRUNCATED)

Adolescent↗
PubMed2000

FES-biofeedback versus intensive pelvic floor muscle exercise for the prevention and treatment of genuine stress incontinence.

We undertook this work to compare the treatment efficacies and the changes of quality of life after pelvic floor muscle (PFM) exercise and the functional electrical stimulation (FES)-biofeedback treatment, both of which are being widely used as conservative treatment methods for female urinary incontinence. We randomly selected 60 female incontinence patients who visited our department and divided them evenly into two groups. They were treated for a period of 6 weeks. The subjective changes in the severity of incontinence and discomfort in daily and social life were measured using a translated version of the questionnaire by Jackson. Objective changes of pelvic muscle contraction force were measured using a perineometer. Pre- and post-treatment maximal pelvic floor muscle contractile (PMC) pressure and changes in the severity of urinary incontinence and discomfort of the two groups showed statistically significant differences (p<0.001). In particular the FES-biofeedback group showed significantly increased maximal PMC pressure and a decreased severity of urinary incontinence and discomfort compared to the intensive PFM exercise group (p<0.001). In conclusion, FES-biofeedback proved more effective than simple PFM exercise.

Activities of Daily Living↗