Biomedical subjects

Wook Jin

Publications and source records attributed to Wook Jin.

11 recordsLinked to original sources

PubMed2006

MR arthrography in the differential diagnosis of type II superior labral anteroposterior lesion and sublabral recess.

OBJECTIVE: The objective of our study was to assess the utility of five MR arthrographic findings in differentiating type II superior labral anteroposterior (SLAP) lesion from superior sublabral recess. MATERIALS AND METHODS: The MR arthrograms of 55 patients (57 cases) with either type II SLAP lesion (34 cases) or superior sublabral recess (23 cases) who underwent arthroscopic surgery and MR arthrography were retrospectively reviewed. Two independent reviewers searched for the extension, direction, and shape of high signal intensity in the superior labrum on MR arthrograms. In addition, the presence of concomitant anterosuperior labral tear and anteroposterior extension of high signal intensity on axial images was evaluated. The frequencies of these findings in cases of type II SLAP lesion and sublabral recess were evaluated, and the statistical significance of each finding in differentiation of the two groups was assessed. RESULTS: Extension of high signal intensity behind the biceps anchor that extended beneath the labrum on fat-saturated oblique coronal T1-weighted images was found in 33 (97%) of the cases of type II SLAP lesion and 21 (91%) of the cases of sublabral recess. Laterally curved high signal intensity was found in 17 (50%) of the cases of type II SLAP lesion but in only four (17%) of the cases of sublabral recess. Globular or irregular shape of the superior labrum was present in 22 (65%) of the cases of type II SLAP lesion and in 10 (43%) of the cases of sublabral recess. Concomitant anterosuperior labral tear was seen in 14 (41%) of the cases of type II SLAP lesion but in only two (8.7%) of the cases of sublabral recess. Anteroposterior extension of high signal intensity in the superior labrum on fat-saturated axial T1-weighted images was detected in 33 cases of type II SLAP lesion (97%) and in 14 cases of sublabral recess (61%). CONCLUSION: Although the MR arthrographic findings were similar for type II SLAP lesion and sublabral recess, laterally curved high signal intensity on oblique coronal images, concomitant anterosuperior labral tear, and anteroposterior extension of high signal intensity on axial images were helpful findings in the diagnosis of type II SLAP lesion.

Adolescent↗

PubMed2006

Diagnostic values of sonography for assessment of sternal fractures compared with conventional radiography and bone scans.

OBJECTIVE: This study was prospectively undertaken to evaluate the diagnostic value of sonography for detection of sternal fractures. We compared sonographic, conventional radiographic, and bone scan examinations of sternal fractures. METHODS: Fifty consecutive patients (26 male and 24 female; mean age, 45.2 years) were evaluated. Conventional radiography and sonography were performed in all patients, and bone scans were performed in 39 patients. All patients had acute pain and tenderness in anterior midline chest areas. Sonography was performed by 2 musculoskeletal radiologists within 1 to 2 days after admission. Patients underwent conventional radiography at admission and bone scans within 4 to 7 days after admission. Two radiologists reviewed all imaging findings by means of consensus. In addition, sonography was performed in 20 asymptomatic patients in a normal control group. RESULTS: Conventional radiography depicted sternal fractures in 12 of 50 patients. Sternal fractures were detected in 31 of 50 patients on sonography. Fractures on sonography were located in the manubrium (8 cases), upper sternal body (11 cases), mid sternal body (5 cases), and lower sternal body (7 cases). Bone scans showed sternal hot uptakes (accumulations of the radionuclide used) in 18 of 39 patients. In the control group, there were no bony defects or abnormal contours. CONCLUSIONS: We could detect sternal fractures more effectively with sonography than with conventional radiography and bone scans. In addition, sternal fracture locations showed relatively even distributions, and focal fractures in the manubrium were not easily detected on bone scans.

Adolescent↗

PubMed2005

Up-regulation of defense enzymes is responsible for low reactive oxygen species in malignant prostate cancer cells.

Reactive oxygen species (ROS) are involved in a diversity of important phenomena in the process of tumor development. To investigate the alterations of oxidative stress and their related systems in tumor progression, a variety of components in the antioxidative stress defense system were examined in prostate cancer cell lines, PC3 and LNCaP. Cell surface molecules involved in metastasis were expressed highly in PC3 cells compared with LNCaP cells, and strong invasion ability was shown in PC3 cells only. ROS level in LNCaP cells was twice higher than that in PC3 cells, although nitric oxide (NO) level was similar between the two cell lines. The content of GSH increased up to about 2-fold in PC3 compared with LNCaP. Activities of glutathione reductase, thioredoxin reductase, and glutathione S-transferase except catalase are significantly higher in PC3 cells than in LNCaP cells. Furthermore, oxidative stress-inducing agents caused down-regulation of GSH and glutathione S-transferase much more significantly in LNCaP cells than in PC3 cells. These results imply that malignant tumor cells may maintain low ROS content by preserving relatively high anti-oxidative capacity, even in the presence of stressful agents.

Antioxidants↗

PubMed2005

The ETV6-NTRK3 chimeric tyrosine kinase suppresses TGF-beta signaling by inactivating the TGF-beta type II receptor.

An emerging theme in cancer biology is that although some malignancies occur through the sequential acquisition of different genetic alterations, certain dominantly acting oncoproteins such as those associated with chromosomal translocations have multiple functions and do not require additional mutations for cell transformation. The ETV6-NTRK3 (EN) chimeric tyrosine kinase, a potent oncoprotein expressed in tumors derived from multiple cell lineages, functions as a constitutively active protein tyrosine kinase. Here, we show that EN suppresses TGF-beta signaling by directly binding to the type II TGF-beta receptor, thereby preventing it from interacting with the type I TGF-beta receptor. This activity requires a functional EN protein tyrosine kinase, and type II TGF-beta receptor appears to be a direct target of EN. Our findings provide evidence for a previously undescribed mechanism by which oncogenic tyrosine kinases can block TGF-beta tumor suppressor activity.

Activin Receptors, Type I↗

PubMed2005

Costal osteochondroma presenting as haemothorax and diaphragmatic laceration.

We report the unusual case of an 11-year-old girl who suffered a large haemothorax and lacerated left hemidiaphragm because of a costal osteochondroma arising from the left sixth rib near the costochondral junction. Surgical excision of the osteochondroma was performed and the lacerated diaphragm was repaired.

Bone Neoplasms↗

PubMed2005

Cystic lesions in the posterosuperior portion of the humeral head on MR arthrography: correlations with gross and histologic findings in cadavers.

OBJECTIVE: The purpose of this study was to describe the appearance of cysts in the posterosuperior portion of the humeral head on MR arthrography and to correlate the MRI findings with the gross and histologic findings in cadavers. CONCLUSION: Cysts in the posterosuperior portion of the humeral head (the bare area) were located in the lateral humeral head just posterior to the greater tuberosity. These cysts were lined with collagen connective tissue and were connected to the joint spaces. We suggest that these pseudocysts in the posterosuperior portion of the humeral head may be a normal variant rather than being an abnormal change or vascular channel.

Adult↗

PubMed2005

Tailgut cyst: MRI evaluation.

OBJECTIVE: The purpose of our study was to evaluate the MRI features of tailgut cysts in five patients. CONCLUSION: Our results suggest that MRI may be useful in the diagnosis of tailgut cyst. A multilocular cystic mass in the presacral space is a characteristic MRI finding of tailgut cyst, which may also be revealed as a cystic mass consisting of a large cyst accompanied by a small peripheral cyst. However, further studies are necessary to establish the usefulness of MRI for evaluating tailgut cysts.

Adult↗

PubMed2004

Cephamycin C production is regulated by relA and rsh genes in Streptomyces clavuligerus ATCC27064.

The effects of growth rate and nutrient uptake rate on the production of cephamycin C were determined in the parental strain, deltarelA mutant, and deltarsh null mutant of S. clavuligerus. Production of cephamycin C was inversely related to mycelium growth and the phosphate feed rate was more critical for the production of cephamycin C. On the contrary, the production of cephamycin C was completely abolished in the deltarelA mutant, but not in deltarsh mutant. The changes in the cephamycin C production by disruption of the relA and rsh genes are presumably associated with the consequent ability of the mutants to accumulate (p)ppGpp under nutrient starvation. Therefore, it is concluded that the stringent response of S. clavuligerus to starvation for nutrients is governed mainly by RelA rather than Rsh and that the response is more apparently regulated by the limitation of phosphate.

Anti-Bacterial Agents↗

PubMed2004

Two relA/spoT homologous genes are involved in the morphological and physiological differentiation of Streptomyces clavuligerus.

This study is focused on the involvement of the unusual nucleotide (p)ppGpp during the morphological and physiological differentiation of Streptomyces clavuligerus. In particular, the functional and structural elements of two genes encoding the proteins RelA and Rsh were identified. The relA gene encodes an 843 aa protein (RelA), while the rsh gene encodes a 738 aa protein (Rsh). The relA and rsh genes were disrupted by the insertion of a hygromycin resistance gene and an apramycin resistance gene, respectively. The synthesis of ppGpp in the relA gene-disrupted mutant was completely eliminated under conditions of starvation for amino acids, whereas synthesis persisted, but was greatly reduced in the rsh gene-disrupted mutant. The relA gene-disrupted mutant had a bald appearance on agar plate cultures and retarded growth in submerged culture, while the rsh-disrupted mutant was unchanged in growth characteristics relative to the wild-type culture. The production of both clavulanic acid and cephamycin C were completely abolished in the relA-disrupted mutant. Thus, it is concluded that the relA gene rather than rsh is essential for morphological and physiological differentiation in S. clavuligerus and that RelA primarily governs the stringent response of S. clavuligerus to starvation for amino acids.

Bacterial Proteins↗

PubMed2003

A highly conserved NTRK3 C-terminal sequence in the ETV6-NTRK3 oncoprotein binds the phosphotyrosine binding domain of insulin receptor substrate-1: an essential interaction for transformation.

Receptor tyrosine kinases are integral components of cellular signaling pathways and are frequently deregulated in malignancies. The NTRK family of neurotrophin receptors mediate neuronal cell survival and differentiation, but altered NTRK signaling has also been implicated in oncogenesis. The ETV6-NTRK3 (EN) gene fusion occurs in human pediatric spindle cell sarcomas and secretory breast carcinoma, and encodes the oligomerization domain of the ETV6 transcription factor fused to the protein-tyrosine kinase domain of NTRK3. The EN protein functions as a constitutively active protein-tyrosine kinase with potent transforming activity in multiple cell lineages, and EN constitutively activates both the Ras-MAPK and phosphatidylinositol 3-kinase-Akt pathways. EN transformation is associated with constitutive tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1). Further, IRS-1 functions as the adaptor protein linking EN to downstream signaling pathways. However, the exact nature of the EN-IRS-1 interaction remains unknown. We now demonstrate that EN specifically binds the phosphotyrosine binding domain of IRS-1 via an interaction at the C terminus of EN. An EN mutant lacking the C-terminal 19 amino acids does not bind IRS-1 and lacks transforming ability. Moreover, expression of an IRS-1 polypeptide containing the phosphotyrosine binding domain acts in a dominant negative manner to inhibit EN transformation, and overexpression of IRS-1 potentiates EN transforming activity. These findings indicate that EN.IRS-1 complex formation through the NTRK3 C terminus is essential for EN transformation.

Agar↗

PubMedDate not supplied

Anomaly of the portal vein with total ramification of the intrahepatic portal branches from the right umbilical portion: CT features.

PURPOSE: To describe CT findings of portal vein anomaly with total ramification of the intrahepatic portal branches from the right umbilical vein. METHODS: Retrospective analysis was performed in 6 patients with portal vein anomaly with total ramification of the intrahepatic portal branches from the right umbilican vein. We analyzed the position of the umbilical portion of the portal vein and ligamentum teres, and determined the intrahepatic branching pattern of the portal vein. RESULTS: The umbilical portion and ligamentum teres were deviated to the right and seen above the gallbladder fossa in all 6 patients. All major braches of the portal vein ramified from the right umbilical vein in all 6 patients. CONCLUSION: The possibility of this portal vein anomaly should be kept in mind when hepatic resection or partial liver transplantation is required.

Aged↗