Biomedical subjects

J Jung

Publications and source records attributed to J Jung.

At least 55 records · Page 3Linked to original sources

PubMed2001

Ultrasonographic observation of intestinal mobility of dogs after acupunctural stimulation on acupoints ST-36 and BL-27.

objectives of this study were to observe normal peristalsis and mixing (or segmental movements) and to evaluate an acupuncture stimulation (ST-36 and BL-27) on the intestinal (duodenum) motility in normal dogs using duplex Doppler sonography. Fifteen healthy Beagle dogs were used for this experiment after the administration of warm saline and pellet feeding. The duodenal motility was examined using duplex Doppler sonography. Six hours after the pellet feeding, an electroacupuncture stimulation at ST-36 and BL-27 was applied and the duodenal motility was examined using duplex Doppler sonography pre-stimulation, during the stimulation and post-stimulation. After saline and pellet administration, the duplex Doppler sonograms showed 3 types of peristalsis and a mixing type (or segmental movement) of duodenum motility. In the peristalsis types, most yielded high-amplitude signals which had one high peak (type-1), two high peaks (type-2), and three high peaks (type-3) and lasted more than 1.3 seconds. Mixing type of duodenum motility had weak signals and were lasted more than 1.5 seconds. Among the peristalsis types, the type 1 and type 2 were predominant and the type 3 was rarely observed. The frequency of intestinal motility stimulated by ST-36 acupoint was increased during the acupuncture stimulation (20% increase compared to the basal value) and decreased (7% decrease compared to the basal value) after stimulation. The frequency of intestinal motility stimulated by BL-27 acupoint was decreased during the acupuncture stimulation (31% decrease compared to the basal value) and increased (18% increase compared to the basal value) after stimulation. There was a significant increase between the value found in during and the post-stimulation tests. We conclude that duplex Doppler studies permit a graphic visualization of intestinal movements which can be qualitatively and quantitatively analyzed using this technique, it is possible to evaluate the gastrointestinal motility after an acupuncture

Acupuncture Points↗

PubMed2000

Identification of the self-interaction of rat TCTP/IgE-dependent histamine-releasing factor using yeast two-hybrid system.

To further understand the biological function of translationally controlled tumor protein (TCTP), also known as IgE-dependent histamine-releasing factor (HRF), the yeast two-hybrid system was used to screen interacting molecules. We isolated cDNA clones coding for TCTP/HRF, suggesting that it may have a self-interacting property. Domain mapping of the interaction revealed that the C-terminal region of residue 126-172 is involved in self-interaction. The self-interacting property of TCTP/HRF was further supported by FPLC gel-filtration chromatography and coimmunoprecipitation analysis from transfected COS-7 cells. Our data suggests that TCTP/HRF may have a potential to self-interact through the C-terminal region, and the self-interaction property may be related to its biological function.

Animals↗

PubMed2000

Effects of matrix metalloproteinase-9 gene knock-out on morphological and motor outcomes after traumatic brain injury.

Matrix metalloproteinases (MMPs) belong to a class of extracellular proteinases responsible for maintaining and remodeling the extracellular matrix. In addition to multiple functions in normal physiology, abnormal MMP expression and activity may also participate in the pathophysiology of cerebral disease. Here, we show that MMP-9 (gelatinase B; EC.3.4.24.35) contributes to the pathophysiology of traumatic brain injury. After controlled cortical impact in mice, MMP-9 was increased in traumatized brain. Total MMP-9 levels at 24 hr were significantly increased as measured by a substrate cleavage assay. Zymograms showed that MMP-9 was elevated as early as 3 hr after traumatic brain injury, reaching a maximum at approximately 24 hr. Increased MMP-9 levels persisted for up to 1 week. Western blot analysis indicated increased profiles of MMP-9 expression that corresponded with the zymographic data. Knock-out mice deficient in MMP-9 gene expression were compared with wild-type littermates in terms of morphological and motor outcomes after trauma. Motor outcomes were measured at 1, 2, and 7 d after traumatic brain injury by the use of a rotarod device. MMP-9 knock-out mice had less motor deficits than wild-type mice. At 7 d, traumatic brain lesion volumes on Nissl-stained histological sections were significantly smaller in MMP-9 knock-out mice. These data demonstrate that MMP-9 contributes to the pathophysiology of traumatic brain injury and suggest that interruption of the MMP proteolytic cascade may be a possible therapeutic approach for preventing the secondary progression of damage after brain trauma.

Analysis of Variance↗

PubMed2000

Formulation and in vivo evaluation of omeprazole buccal adhesive tablet.

For the development of omeprazole buccal adhesive tablets, we studied the release and bioavailability of omeprazole delivered by buccal adhesive tablets composed of sodium alginate, hydroxypropylmethylcellulose (HPMC), magnesium oxide and croscarmellose sodium. Croscarmellose sodium enhanced the release of omeprazole from the tablets. The analysis of the release mechanism showed that croscarmellose sodium changed the release profile of omeprazole from first- to zero-order release kinetics by forming porous channels in the tablet matrix. However, it decreased the bioadhesive forces and stability of omeprazole tablets in human saliva. The tablet is composed of omeprazole-sodium alginate-HPMC-magnesium oxide-croscarmellose sodium (20:24:6:50:10 mg). It may be attached to the human cheek without collapse and it enhanced the stability of omeprazole in human saliva for at least 4 h, giving a fast release of omeprazole. The plasma concentration of omeprazole in hamsters increased to reach a maximum of 370 ng/ml at 45 min after buccal administration and remained at the high level of 146-366 ng/ml for 6 h. The buccal bioavailability of omeprazole in hamsters was 13.7+/-3.2%. These results demonstrate that the omeprazole buccal adhesive tablet would be useful to deliver omeprazole which degrades very rapidly in acidic aqueous medium and undergoes hepatic first-pass metabolism after oral administration.

Adhesiveness↗

PubMed2000

The cAMP-dependent kinase pathway does not sensitize the cloned vanilloid receptor type 1 expressed in xenopus oocytes or Aplysia neurons.

Capsaicin-activated channels present in sensory neurons are ligand-gated cation channels that largely account for mediating some types of pain. The cAMP-dependent protein kinase (PKA) signal pathway was suggested to mediate the prostaglandin-induced enhancement of capsaicin-evoked inward current (I(CAP)) in rat sensory neurons. It is not clear, however, whether PKA acts directly on the capsaicin-sensitive channel that is responsible for I(CAP). To address this issue, we overexpressed the cloned capsaicin receptor, VR1, in heterologous expression systems such as Xenopus oocytes or Aplysia R2 neuron and stimulated PKA pathways. As a result, activation of PKA by applying either 8-bromo-cAMP or forskolin with 3-isobutyl-1-methylxanthine or through activation of beta(2) adrenergic receptors failed to enhance I(CAP) in oocytes or R2 neurons expressing VR1. Our results raise two possibilities. (1) Direct phosphorylation of VR1 by PKA may not be responsible for the sensitization; instead, phosphorylation of regulatory proteins associated with VR1 would account for the sensitization of I(CAP) evoked by prostaglandin E(2) in dorsal root ganglion (DRG) neurons. (2) DRG neurons may have a different PKA signaling mechanism that is not replicable in Xenopus oocytes or Aplysia R2 neurons.

1-Methyl-3-isobutylxanthine↗

PubMed2000

The SHORT-ROOT gene controls radial patterning of the Arabidopsis root through radial signaling.

Asymmetric cell divisions play an important role in the establishment and propagation of the cellular pattern of plant tissues. The SHORT-ROOT (SHR) gene is required for the asymmetric cell division responsible for formation of ground tissue (endodermis and cortex) as well as specification of endodermis in the Arabidopsis root. We show that SHR encodes a putative transcription factor with homology to SCARECROW (SCR). From analyses of gene expression and cell identity in genetically stable and unstable alleles of shr, we conclude that SHR functions upstream of SCR and participates in a radial signaling pathway. Consistent with a regulatory role in radial patterning, ectopic expression of SHR results in supernumerary cell divisions and abnormal cell specification in the root meristem.

Amino Acid Sequence↗

PubMed2000

Direct activation of capsaicin receptors by products of lipoxygenases: endogenous capsaicin-like substances.

Capsaicin, a pungent ingredient of hot peppers, causes excitation of small sensory neurons, and thereby produces severe pain. A nonselective cation channel activated by capsaicin has been identified in sensory neurons and a cDNA encoding the channel has been cloned recently. However, an endogenous activator of the receptor has not yet been found. In this study, we show that several products of lipoxygenases directly activate the capsaicin-activated channel in isolated membrane patches of sensory neurons. Among them, 12- and 15-(S)-hydroperoxyeicosatetraenoic acids, 5- and 15-(S)-hydroxyeicosatetraenoic acids, and leukotriene B(4) possessed the highest potency. The eicosanoids also activated the cloned capsaicin receptor (VR1) expressed in HEK cells. Prostaglandins and unsaturated fatty acids failed to activate the channel. These results suggest a novel signaling mechanism underlying the pain sensory transduction.

Animals↗

PubMed2000

Regulation of CD27 expression in the course of germinal center B cell differentiation: the pivotal role of IL-10.

The molecules of the TNF superfamily and their receptors play crucial roles in the humoral immune response. In view of the powerful effects on germinal center (GC) B cell differentiation, the expression of these molecules should be tightly regulated. In this study, we have undertaken a detailed analysis of the regulation of CD27 expression following the differentiation of GC B cells supported by a follicular dendritic cell line. We show that CD27 is differentially expressed on B cell subpopulations at different stages of differentiation. Naive B cells are virtually negative but plasma cells generated in vivo are strongly positive for CD27 expression. GC B cells that exhibit a moderate expression of CD27 remarkably up-regulate the expression levels of this molecule when they differentiate into plasma cells, which is induced by IL-10. The up-regulation of CD27 expression correlates with that of CD38. Therefore, high expression of CD27 molecules emerges as a specific marker for plasma cells. Our results suggest an important role for CD27 in the differentiation of GC B cells into plasma cells. Evaluation of CD27 expression levels may be of a clinical significance in assessment of B cell maturation in immunocompromised patients.

Animals↗

PubMed2000

[Morphological changes in correlation with so-called idiopathic ventricular tachycardias from the right ventricular outflow tract].

"Idiopathic" ventricular tachycardia is an exclusion diagnosis. The underlying reasons and mechanisms of "idiopathic" ventricular tachycardias are still not completely understood. Recent investigations showed a high prevalence of morphological abnormalities in the right ventricle of patients with "idiopathic" ventricular tachycardia out of the right ventricular outflow tract, which could often be correlated with the origin of the ventricular tachycardia. These described abnormalities were not uniform. Here we report about a patient suffering from drug-refractory "idiopathic" ventricular tachycardia for 10 years. This is the first report in which the origin of an "idiopathic" ventricular tachycardia could be localized by right-ventricular angiography, magnetic resonance tomography and electrophysiological study in the area of an interventricular septal thickening of the right ventricular outflow tract and cured by radiofrequency catheter ablation.

Catheter Ablation↗

PubMed2000

[Atrial defibrillators].

The promising results achieved with low-energy, internal atrial cardioversion have stimulated the development of an implantable atrial defibrillator. Initial clinical experience with the Metrix system in a group of highly selected patients with refractory atrial fibrillation (AF) suggests that atrial defibrillation can be performed effectively and safely by using a stand-alone device. The extension of this therapy will depend on the results of further prospective studies comparing this new therapeutic option with other new non-pharmacological methods to treat AF. Internal atrial cardioversion is feasible at low energies with current endocardial transvenous lead configurations primarily designed for ventricular defibrillation. As AF is a frequent arrhythmia in implantable cardioverter defibrillator recipients, the capability for atrial defibrillation has recently been incorporated in a newly designed dual chamber defibrillator (Jewel AF system). Initial clinical experience with this device that combines both detection and treatment in the atrium as well as in the ventricle indicates a significant improvement in the management of patients with both supraventricular and ventricular tachyarrhythmias.

Adult↗

PubMed2000

Effects of mixing on fed-batch fermentation of L-ornithine.

The effects of mixing on L-ornithine fermentation were studied using an L-arginine auxotrophic mutant of Brevibacterium ketoglutamicum ATCC 21092. Three different modes of fed-batch culture using two different impeller types were studied in a 7 l fermentor. The first two modes of fed-batch culture were carried out in a fermentor equipped with six-flat-blade disk-turbine impellers with top and bottom feeding. The third mode of fed batch culture was carried out using pitched-six-flat-blade disk-turbine impellers with top feeding. The titre of L-ornithine increased up to 1.8 fold with bottom-feeding or when the pitched-six-flat-blade disk-turbine impellers were used compared to when the six-flat-blade disk-turbine impellers with top-feeding were used. It was observed that the mixing time of the limiting nutrients varied significantly depending on both the direction of feeding and the impeller type. Since the profiles of the specific rates of CO2 evolution, oxygen and glucose uptakes were very similar for the three culture modes, it could be reasonably assumed that the microorganism exhibited similar growth rates for each mode used. However, different amino acid producing activities were observed in the three culture modes. From these results it is concluded that the productivity of L-ornithine fermentation is significantly improved by shortening the mixing time of the limiting nutrient in the fermentor.

Journal Article↗

PubMed2000

Protein structure alignment using environmental profiles.

A new protein structure alignment procedure is described. An initial alignment is made by comparing a one-dimensional list of primary, secondary and tertiary structural features (profiles) of two proteins, without explicitly considering the three-dimensional geometry of the structures. The alignment is then iteratively refined in the second step, in which new alignments are found by three-dimensional superposition of the structures based on the current alignment. This new procedure is fast enough to do all-against-all structural comparisons routinely. The procedure sometimes finds an alignment that suggests an evolutionary relationship and which is not normally obtained if only geometry is considered. All pair-wise comparisons were made among 3539 protein structural domains that represent all known protein structures. The resulting 3539 z-scores were used to cluster the proteins. The number of main clusters increased continuously as the z-cutoff was raised, but the number of multiple-member clusters showed a maximum at z-cutoff values of 5.0 and 5.5. When a z-cutoff value of 5.0 was used, the total number of main clusters was 2043, of which only 336 clusters had more than one member.

Amino Acid Sequence↗

PubMed2000

Molecular analysis of the SCARECROW gene in maize reveals a common basis for radial patterning in diverse meristems.

Maize and Arabidopsis root apical meristems differ in several aspects of their radial organization and ontogeny. Despite the large evolutionary distance and differences in root radial patterning, analysis of the putative maize ortholog of the Arabidopsis patterning gene SCARECROW (SCR) revealed expression localized to the endodermis, which is similar to its expression in Arabidopsis. Expression in maize extends through the quiescent center, a population of mitotically inactive cells formerly thought to be undifferentiated and to lack radial pattern information. Zea mays SCARECROW (ZmSCR), the putative maize SCR ortholog, was used as a molecular marker to investigate radial patterning during regeneration of the root tip after either whole or partial excision. Analysis of the dynamic expression pattern of ZmSCR as well as other markers indicates the involvement of positional information as a primary determinant in regeneration of the root radial pattern.

Amino Acid Sequence↗

PubMed2000

Use of residue pairs in protein sequence-sequence and sequence-structure alignments.

Two new sets of scoring matrices are introduced: H2 for the protein sequence comparison and T2 for the protein sequence-structure correlation. Each element of H2 or T2 measures the frequency with which a pair of amino acid types in one protein, k-residues apart in the sequence, is aligned with another pair of residues, of given amino acid types (for H2) or in given structural states (for T2), in other structurally homologous proteins. There are four types, corresponding to the k-values of 1 to 4, for both H2 and T2. These matrices were set up using a large number of structurally homologous protein pairs, with little sequence homology between the pair, that were recently generated using the structure comparison program SHEBA. The two scoring matrices were incorporated into the main body of the sequence alignment program SSEARCH in the FASTA package and tested in a fold recognition setting in which a set of 107 test sequences were aligned to each of a panel of 3,539 domains that represent all known protein structures. Six procedures were tested; the straight Smith-Waterman (SW) and FASTA procedures, which used the Blosum62 single residue type substitution matrix; BLAST and PSI-BLAST procedures, which also used the Blosum62 matrix; PASH, which used Blosum62 and H2 matrices; and PASSC, which used Blosum62, H2, and T2 matrices. All procedures gave similar results when the probe and target sequences had greater than 30% sequence identity. However, when the sequence identity was below 30%, a similar structure could be found for more sequences using PASSC than using any other procedure. PASH and PSI-BLAST gave the next best results.

Algorithms↗

PubMed2000

Cytochrome b6/f complex as an indigenous photodynamic generator of singlet oxygen in thylakoid membranes.

Possible association of photodynamic sensitization by cytochrome b6/f complex (cyt b6/f) via singlet oxygen (1O2) mechanism with photoinhibition damage to photosystem II (PS II) was studied using such subthylakoid preparations as photosystem I (PS I) particles, PS II core complex and cyt b6/f from spinach leaves. Upon exposure to bright light, PS II core complex lost photosynthetic electron transport activity to a certain extent, whose-spectral dependence implied that pheophytin a is likely involved in photoinactivation of PS II core complex in itself. The presence of PS I particles exerted virtually no effect on PS II core photoinactivation. However, the inclusion of cyt b6/f in samples resulted in a marked exacerbation of the photoinactivation, particularly in UV-A and blue light. Such effect of cyt b6/f was suppressed by azide and enhanced by the medium deuteration. Photogeneration of 1O2 from cyt b6/f was confirmed by ESR and spectrophotometry, chemically trapping 1O2. Action spectra for both 1O2 photoproduction and PS II core photoinactivation by cyt b6/f bore a close resemblance to each other, seemingly carrying the absorption characteristics of the Rieske Fe-S protein. A complex deficient in the Rieske protein prepared from intact cyt b6/f showed virtually no generation of 1O2 in light, whereas an efficient photoformation of 1O2 was seen in the Rieske protein preparation. The results suggest that cyt b6/f, rather specifically the Rieske center, may play a prominent role in photoinhibition processes through type II photosensitization in thylakoids.

Cytochrome b Group↗

PubMed2000

Three cases of pancreas allograft dysfunction.

We present dincopathologic features of three cases of biopsy-proven pancreas allograft dysfunction in Korea. All patients had advanced insulin-dependent diabetes mellitus (IDDM). Case 1 was a 30-year-old woman who underwent a simultaneous pancreas-kidney transplantation. Urinary infection developed 6 days after the operation, which remitted and reappeared, when urine amylase level was normal. Since the 55th day after the operation, intermittent hematuria has persisted. Cytomegalovirus inclusions were detected on the urinary bladder and grafted duodenal mucosa. The graft was removed due to perforation of the grafted duodenum and panperitonitis. Case 2 was a 27-year-old man undergoing pancreas transplantation alone (PTA). Ten days after the transplatation, the level of 24 urine amylase decreased and the graft was not delineated by 99mTc DTPA scintigraphy. Allograft needle biopsy revealed multiple acinar cell necrosis and mild lymphocytic infiltration which were compatible with mild acute rejection. Case 3 was a 25-year-old man undergoing cadevaric PTA. Three months after the transplantation, graft was removed due to gastric perforation associated with cytomegalovirus and angiodestructive fungal infection. Various causes of pancreas allograft dysfunction can be diagnosed by needle biopsy, thus appropriate biopsy specimen should be taken using improved biopsy technique.

Adult↗

PubMed2000

[Drug and electrical therapy of supraventricular tachyarrhythmias].

This article reviews current pharmacological and electrical approaches to the restoration of sinus rhythm in patients who suffer from atrial fibrillation and atrial flutter. Spontaneous conversion to sinus rhythm occurs in a high proportion of atrial fibrillation of < 24 h duration. Among patients presenting with atrial fibrillation, which was clinically estimated to have lasted < 48 h, the likelihood of cardioversion-related clinical thromboembolism is low, which supports the current practice of early cardioversion without anticoagulation. Antiarrhythmic drugs effective in terminating atrial fibrillation of short duration are those which possess class IA, IC and III properties. Electrical transthoracic cardioversion by using different electrode positions and additional pressure over the electrodes during shock delivery is a highly effective and well-tolerated method in restoration of sinus rhythm even in patients under conscious sedation. Immediate spontaneous reinitiation of atrial fibrillation can occur in a significant proportion of patients undergoing electrical cardioversion and can be reduced after a pretreatment with antiarrhythmic drugs. In patients with failed external cardioversion, internal low energy cardioversion offers an effective option for restoring sinus rhythm. After cardioversion in a high proportion of patients antiarrhythmic drugs are necessary to prevent atrial fibrillation from recurring. A serial cardioversion approach can prevent the evolution of permanent atrial fibrillation in a subgroup of patients. Overdrive atrial pacing is an effective and minimally invasive procedure for termination of atrial flutter. The acute administration of class IA, IC and III antiarrhythmic drugs increases the success rate of this method in restoring sinus rhythm.

Anti-Arrhythmia Agents↗

PubMed1999

Development of a thermo-reversible insulin liquid suppository with bioavailability enhancement.

The purpose of this work is to develop a thermo-reversible insulin liquid suppository, which undergoes a phase transition to bioadhesive gels at body temperature and enhances the bioavailability of insulin. The effects of insulin and sodium salicylate on the physicochemical properties of a liquid suppository composed of poloxamer P 407, P 188 and polycarbophil were investigated. The pharmacodynamic study and quantitative histological assessment of the rectal mucosa of rats were carried out after the dose of insulin-loaded liquid suppositories with different amounts of sodium salicylate into streptozotocin-treated rats. Only thermo-reversible insulin liquid suppository [insulin/P407/P188/polycarbophil/sodium salicylate (100 (IU/g)/15/20/0.2/10%)] showed the optimal physicochemical properties and good safety in rats. It gave significantly lower plasma glucose levels, AUC(0-->4h) (the area below basal glucose level) and C(nadir) (the plasma glucose levels at the nadir) than did the solid and liquid suppositories without sodium salicylate in rats, indicating that the insulin from liquid suppository with sodium salicylate could be well absorbed in rats due to the absorption enhancing effect of sodium salicylate. It is concluded that thermo-reversible insulin liquid suppository [insulin/P 407/P 188/polycarbophil/sodium salicylate (100 (IU/g)/15/20/0.2/10%)], which was easy to administer without any pain during insertion and remained at the administered sites, could have a potential to be developed as a more convenient, safe and effective rectal delivery system of insulin.

Administration, Rectal↗