Search PubMed⌕ Search

Biomedical subjects

J H Chang

Publications and source records attributed to J H Chang.

At least 19 recordsLinked to original sources
PubMed2006

Toll-like receptors in ocular immunity and the immunopathogenesis of inflammatory eye disease.

Microbial agents have an important role in the pathogenesis of various inflammatory eye diseases, such as uveitis and keratitis. Microbial infections of the eye such as microbial keratitis, ocular onchocerciasis, bacterial endophthalmitis, viral retinitis, and other infectious uveitis are unfortunately common. In addition, microbial agents have been implicated in the pathogenesis of "non-infectious" immune mediated diseases such as HLA-B27 associated acute anterior uveitis. Toll-like receptors (TLR) are a family of pattern recognition receptors that initiates rapid host innate immune response to microbial components known as pathogen associated molecular patterns, which are unique to a given class of microbes, such as lipopolysaccharide of Gram negative bacteria. Recent in vitro and in vivo studies have demonstrated the expression and function of TLRs in the eye, with significant implications for better understanding of ocular immunity and the pathogenesis of inflammatory eye diseases affecting the cornea, uvea, and retina.

Eye↗
PubMed2006

A review of recent unexpected animal disease events in Japan and Korea and the follow-up action taken.

In Japan, the need to improve countermeasures against biological weapons was recognised after the Aum Shinrikyo cult attempted to use biological weapons in 1995. This paper describes how the two relevant ministries in Japan worked together to cope with recent disease outbreaks, including cases of classical swine fever (CSF) and avian influenza, which evidence suggests might have been the result of the deliberate misuse of unauthorised vaccines that had been illegally imported. By implementing successful control measures the two ministries were able to eradicate all the diseases within very short periods. In the past few years, the Republic of Korea has also experienced outbreaks of foot and mouth disease, highly pathogenic avian influenza, and CSF, all of which had previously been absent (or had been eradicated) in Korea. A review of the historical background, major events of the outbreaks and the control measures which were implemented are presented here.

Animal Diseases↗
PubMed2004

Cysticercosis of cerebellopontine cistern: differential diagnosis using MRI.

We report an example of subarachnoid neurocysticercosis located in the left cerebellopontine cistern of a 60 year-old man. The negative results of the serum and cerebrospinal fluid tests for parasites and the unusual MRI findings, such as the uncommon shape, location and extension pattern, made differential diagnosis difficult. Neurocysticercosis was confirmed by surgical and histopathological findings. The clinical and radiographic features of neurocysticercosis are highly variable. In an endemic area, neurocysticercosis should be considered in the differential diagnosis.

Brain Stem↗
PubMed2004

Radiographic contrast study of the upper gastrointestinal tract of eight dogs using carboxymethylcellulose mixed with a low concentration of barium sulphate.

To evaluate the efficacy of a mixture of barium and carboxymethylcellulose (CMC) suspension in upper gastrointestinal contrast studies, and to determine its optimal concentration and method for use, eight healthy beagle dogs underwent conventional upper gastrointestinal contrast imaging and a modified procedure using a mixture of barium sulphate and CMC. Four different procedures were carried out on the dogs at weekly intervals. In the first, the dogs were administered 10 ml/kg of 60 per cent barium suspension for conventional study of the upper gastrointestinal tract. The second, third and fourth procedures involved modified methods in which the dogs were given 10 ml/kg of a mixture of 25 per cent barium and 0.5 per cent CMC prepared to a low, moderate or high viscosity, respectively. All four procedures were evaluated by four criteria: the quality of the images obtained, the translucency and distensibility of the bowel, and the transit time. The method of imaging which used a moderately viscious CMC formulation provided excellent image quality, high translucency, a rapid transit time and suitable bowel distension to enable more precise diagnosis of disorders of the gastrointestinal tract.

Administration, Oral↗
PubMed2004

Expression and characterization of a recombinant Cry1Ac crystal protein with enhanced green fluorescent protein in acrystalliferous Bacillus thuringiensis.

AIMS: To investigate fusion expression between Bacillus thuringiensis crystal protein and a foreign protein, the expression of a fusion protein comprised of Cry1Ac, and enhanced green fluorescent protein (EGFP) in B. thuringiensis Cry(-)B strain was examined. METHODS AND RESULTS: The N-terminal fusion expression of EGFP in Cry1Ac was attempted under the control of the native cry1Ac promoter. The EGFP gene was cloned into pProMu and named pProMu-EGFP. The transformant, ProMu-EGFP/CB produced parasporal inclusions that were of bipyramidal-shaped crystals in size ranging from 200 to 300 nm. The fusion protein was approximately 150 kDa and identified by the immunoblot analysis using a Cry1Ac antibody and also a GFP antibody. The LC(50) of the ProMu-EGFP/CB was twofold higher when compared with that by the ProAc/CB. However, the crystal protein produced by the ProMu-EGFP/CB was effective on Plutella xylostella larvae. CONCLUSIONS: The ProMu-EGFP/CB produced bipyramidal shaped and insecticidal crystals comprising fusion proteins. SIGNIFICANCE AND IMPACT OF THE STUDY: Through the N-terminal fusion expression of EGFP and Cry1Ac, expression and crystallization between the B. thuringiensis crystal protein and a foreign protein were validated.

Animals↗
PubMed2003

Simple bone cyst occurring in calvarium.

A 60 year-old female presented with a non-specific headache that she had experienced for 4 years. A simple skull X-ray indicated a well-defined, lobulated and radiolucent lesion with a thin sclerotic rim involving the parietal bone (Fig. 1A). Computed tomography revealed a hypodense lesion. Magnetic resonance imaging showed a 2 cm-sized cystic lesion in the diploic space with both tabular involvement. This lesion was not enhanced by contrast agent. It was well defined and the periosteum was intact. The cyst paralleled the CSF in signal intensity on all pulse sequences. No fluid levels were detected (Fig. 1B, C, D). After the scalp was incised, a semi-translucent and light yellow- to white-coloured bony lesion was easily identified. The outer bony cortex of this lesion was slightly elevated, and the consistency was same as that of the normal skull. A craniectomy was performed and the cystic skull lesion was removed. The inner surface of this cystic lesion was intact but appeared irregular. The cystic cavity was empty and the dura did not appear to be involved. Histologically, it was a simple cystic cavity without lining epithelium, and the surrounding bony structures were normal (Fig. 1E, F). It was diagnosed as a simple bone cyst (SBC). The postoperative course was uneventful.

Bone Cysts↗
PubMed2003

Lung function in patients with chronic airflow obstruction due to tuberculous destroyed lung.

Lung function in cases of chronic airflow obstruction (CAO) due to tuberculous destroyed lung, which is still common in Korea, has not been objectively investigated. We evaluated lung functions and postbronchodilator responses in 21 CAO patients with a forced expiratory volume in 1 s (FEV1) of 30-65% of the predicted value, and compared some of these results with those of age-, sex- and FEV1% predicted-matched patients with chronic obstructive pulmonary disease (COPD). In addition, we analyzed the lung functions of CAO patients with respect to wheezing. The forced vital capacity (FVC) (P < 0.05) and postbronchodilator FEV1 of CAO patients were lower than those of COPD patients (P < 0.05). When a positive bronchodilator response was defined as an absolute change of FEV1 (FEV1 delta(abs)) of more than 0.2 l (P < 0.05) and a percentage of initial FEV1 (FEV1 delta%init) of more than 12%, the positive rates in CAO patients were lower than in COPD patients (P < 0.05). Among the CAO patients, patients with wheezing showed lower forced expiratory flow 25%-75% (FEF(25-75%)) (P < 0.05) and higher airway resistance than those without wheezing (P < 0.05). CAO patients with wheezing were more responsive to bronchodilator than those without wheezing. Although the pathophysiology of CAO differs from that of COPD, bronchodilator therapy could be useful for treating CAO, especially in cases presenting with wheezing.

Aged↗
PubMed2003

Complications after gamma knife radiosurgery for benign meningiomas.

OBJECTIVES: To analyse the results of gamma knife radiosurgery (GKS) for the treatment of intracranial meningiomas and to assess possible factors related to the outcome and complications of such treatment. METHODS: The authors retrospectively reviewed the clinical and radiological data of 179 patients (194 lesions) treated with GKS for meningiomas between May 1992 and October 2000. The mean follow up duration was 37.3 months (range 6.4 to 86.3 months). The study determined the correlation between radiosurgical outcome including imaging changes after GKS and multiple factors such as tumour location and size, patient characteristics, venous sinus status, pre-GKS degree of oedema, other treatment modalities, and radiosurgical parameters. RESULTS: The radiological control rate was 97.1%. Magnetic resonance imaging (MRI) showed complications after GKS in 35 lesions (25.0%) among the 140 lesions followed up with MRI. Complications were divided into peritumorous imaging changes (33 lesions; 23.6%) and transient cranial nerve dysfunction (two lesions; 1.4%). Radiation induced imaging changes were seen mostly in convexity, parasagittal, and falx meningiomas that were deeply embedded in the cortex. About 60% of these were asymptomatic and the overall rate of symptomatic imaging changes was 9.3%. Neurological deficit related to imaging changes developed in only three patients, and all the symptoms were transient. CONCLUSION: GKS for intracranial meningiomas seems to be a safe and effective treatment. However, meningiomas of the convexity, parasagittal region, or falx cerebri have a higher incidence of peritumorous imaging changes after GKS than those of the skull base. Therefore, the use of GKS needs to be considered very cautiously in cerebral hemispheric meningiomas, taking into consideration patient age and general condition, tumour size and location, pattern of cortical embedding, relation between the tumour and venous sinuses, presenting symptoms, and patient preference.

Adolescent↗
PubMed2003

Baculovirus expression vectors that incorporate the foreign protein into viral occlusion bodies.

Current baculovirus expression systems typically produce soluble proteins that accumulate within the infected insect cell or are secreted into the growth medium. A system has now been developed for the incorporation of foreign proteins, along with the matrix protein, polyhedrin, into baculovirus occlusion bodies. Initial studies showed that a recombinant virus expressing a translational fusion between polyhedrin and GFP did not form occlusion bodies. However, a baculovirus coexpressing native polyhedrin and the polyhedrin-GFP fusion protein formed occlusion bodies that fluoresced under UV light, demonstrating that they included the polyhedrin-GFP fusion protein. This was confirmed by immunoblot analysis. Thus, incorporation of a foreign protein into occlusion bodies depends on an interaction between native polyhedrin and the polyhedrin fusion protein. Electron microscopy demonstrated that the occlusion bodies containing GFP also incorporated virions as expected. These ColorPol occlusion bodies were as infectious to insect larvae as occlusion bodies produced by wild-type virus. This new system expands the capabilities for foreign gene expression by baculoviruses, which has implications for biopesticide design, novel vaccine delivery systems, and fusion protein purification applications.

Animals↗
PubMed2003

Effect of ets-related transcription factor (ERT) on transforming growth factor (TGF)-beta type II receptor gene expression in human cancer cell lines.

Transcriptional repression of the TGF-beta type II receptor (RII) is one of the mechanisms leading to TGF-beta resistance. The newly identified epithelium-specific ets transcription factor ERT/ESX/ESE-1 binds to the TGF-beta RII promoter and induces promoter activity. This study aims to investigate the mechanisms underlying development of ERT-mediated TGF-beta resistance using antisense ERT oligonucleotide. We performed Northern blot analysis of TGF-beta RII expression in human colon cancer cell line, RKO, after transfecting these cells with MFG-antisense-ERT retroviral construct. The plasmid containing the chloramphenicol acetyltransferase (CAT) gene alone was used as the control. The amount of TGF-beta RII mRNA appears to be poor in RKO cells expressing antisense ERT compared with both parental RKO and control cells. In conclusion, transfection of MFG-antisense-ERT construct into the colon cancer cell line could result in lower levels of TGF-beta RII mRNA expression, which means that ERT mediates the expression of TGF-beta RII and the transcriptional inhibition of ERT could be a one of the mechanisms of colonic carcinogenesis. More in vitro and in vivo studies should be required to evaluate this treatment in clinical setting.

Cell Line, Tumor↗
PubMed2002

Isolation and characterization of a strain of Bacillus thuringiensis ssp. kurstaki containing a new delta-endotoxin gene.

A strain of Bacillus thuringiensis that showed significantly high toxicity to Plutella xylostella and Spodoptera exigua was isolated from a Korean soil sample and characterized. The isolate, named B. thuringiensis K1, was determined to belong to ssp. kurstaki (H3a3b3c) type by an H antisera agglutination test and produced bipyramidal inclusions. Plasmid pattern of K1 was different from that of the reference strain, ssp. kurstaki HD-1, but the parasporal inclusion protein profile of K1 had two major bands that were similar in size to those of ssp. kurstaki HD-1. To verify the delta-endotoxin gene types of K1, PCR analysis with specific cry gene primers was performed to show that K1 contained a new cry gene in addition to cry1Aa, cry1Ab, cry1Ac, cry1E and cry2 genes. PCR-amplified region of the new cry gene, cryX, showed 79% similarity to cry1Fa1 gene (GenBank Accession No. M63897). In an insect toxicity assay, K1 had higher toxicity against Plutella xylostella and S. exigua than ssp. kurstaki HD-1.

Animals↗
PubMed2002

Sacral neuromodulation in functional urinary retention: an effective way to restore voiding.

OBJECTIVE: To determine the long-term efficacy and complications of sacral nerve stimulation as an alternative therapy for functional unobstructive urinary retention, often considered to be psychogenic and effectively treated by clean intermittent catheterization, but for which pelvic floor dysfunction has been recognized as a possible cause. PATIENTS AND METHODS: Twenty patients (17 women and three men, mean age 48 years) with idiopathic, unobstructive functional urinary retention and in whom other forms of therapy had failed, had a pulse generator implanted (Medtronic, Minneapolis, MN, USA) and a sacral nerve implant. Their mean duration of symptoms was 68 months; 13 patients had chronic pelvic and perineal pain associated with their obstructive voiding symptoms. All patients were managed with clean intermittent catheterization and pharmacological therapy (alpha-blockers) before the procedure. All patients had a percutaneous nerve evaluation before the permanent implant, which showed> 50% improvement in their symptoms. All patients were evaluated at 1, 6 12, 18 and 24 months, then yearly thereafter. The results were assessed both subjectively by patient's symptoms and objectively by checking the postvoid residual volume (PVR) and voided volume. RESULTS: Eighteen patients were able to void spontaneously with a mean increase in voided volume from 48 to 198 mL, and a significant decrease in PVR from 315 to 60 mL. Eighteen of the patients had a > or = 50% improvement in their symptoms and said they would recommend the therapy to a friend or relative. Complications occurred in six patients. CONCLUSION: Sacral nerve stimulation is an effective and durable new approach to functional urinary retention, with few associated complications. Test stimulation provides a valuable tool for selecting patients.

Adult↗
PubMed2001

Diminished corneal angiogenesis in gelatinase A-deficient mice.

The goal of the present study was to define the role of gelatinase A in angiogenesis. We performed corneal micropocket assays in gelatinase A-deficient mice and their age-matched wild-type littermates. The corneal neovascular area in gelatinase A-deficient mice (0.15+/-0.14 mm(2)) was significantly less than that of wild-type littermates (0.53+/-0.35 mm(2); P<0.01). Similarly, aortic ring assays showed significant reduction of endothelial outgrowth in gelatinase A-deficient mice (0.26+/-0.14 mm(2)) as compared to wild-type littermates (0.44+/-0.06 mm(2); P<0.05). These results suggest that gelatinase A may play an important role in the regulation of corneal angiogenesis.

Animals↗
PubMed2001

Long-lived immune response to early secretory antigenic target 6 in individuals who had recovered from tuberculosis.

We sought to understand the persistence and relevance of the long-lived immune response to early secretory antigenic target (ESAT-6) of Mycobacterium tuberculosis in humans. ESAT-6 is recognized by memory cells involved in protection of animals against tuberculosis (TB). Recent reports also showed that ESAT-6 response can be recovered in patients with TB and in those soon after anti-TB therapy. We chose 18 individuals who had recovered from pulmonary TB (some in remission for >5 years), and 14 bacille Calmette-Guérin-vaccinated healthy individuals for this study. The results showed that peripheral blood mononuclear cells of 10 (55.6%) of 18 patients with TB remission responded to ESAT-6 with stimulation indices >3.0, whereas none of the healthy controls responded. Functional analysis showed that 13 (72.2%) of 18 patients with TB remission produced significant amounts of IFN-gamma in response to ESAT-6, whereas only 1 (7.1%) of the 14 healthy control subjects did so. It appears that responses to ESAT-6 can persist in individuals who had recovered from pulmonary TB.

Adult↗
PubMed2001

Hybrid nanogels for sustainable positive thermosensitive drug release.

A hybrid nanogel has been developed based on interpenetrating networks of thermosensitive poly(N-isopropylacrylamide) gels and tailored nanoporous silica. A sustainable positive thermo-responsive drug release profile is obtained. When the temperature rises, the polymer gel shrinks, squeezing the drug into the porous channels, and at the same time, opening the pores to the outside media. The drug slowly diffuses out of the porous channels. The overall release rate can be adjusted by changing the composition of the nanogel.

Acrylic Resins↗