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Biomedical subjects

Y Kwon

Publications and source records attributed to Y Kwon.

At least 55 records · Page 3Linked to original sources
PubMed1995

Poly (A) binding protein is bound to both stored and polysomal mRNAs in the mammalian testis.

RNA-binding proteins that bind to the 3' untranslated region of mRNAs play important roles in regulating gene expression. Here we examine the association between the 70 kDa poly (A) binding protein (PABP) and stored (RNP) and polysomal mRNAs during mammalian male germ cell development. PABP mRNA levels increase as germ cells enter meiosis, reaching a maximum in the early postmeiotic stages, and decreasing to a nearly nondetectable level towards the end of spermatogenesis. Most of the PABP mRNA is found in the nonpolysomal fractions of postmitochondrial extracts, suggesting that PABP mRNA is either inefficiently translated or stored as RNPs during spermatogenesis. Virtually all of the testicular PABP is bound to either polysomal or nonpolysomal mRNAs, with little, if any, free PABP detectable. Analysis of several specific mRNAs reveals PABP is bound to both stored (RNP) and translated forms of the mRNAs. Western blot analysis and immunocytochemistry indicate PABP is widespread in the mammalian testis, with maximal amounts detected in postmeiotic round spermatids. The presence of PABP in elongating spermatids, a cell type in which PABP mRNA is nearly absent, suggests that PABP is a stable protein in the later stages of male germ cell development. The high level of testicular PABP in round spermatids and in mRNPs suggests a role for PABP in the storage as well as in the subsequent translation of developmentally regulated mRNAs in the mammalian testis.

Animals↗
PubMed1995

Different cholesterol deposition in aorta of Dahl salt-sensitive rats and spontaneously hypertensive rats fed a high-cholesterol diet.

1. We compared the serum and aortic lipid levels in spontaneously hypertensive rats (SHR) and Dahl salt-sensitive rats (DSR) fed a high-cholesterol (HC) diet. 2. In SHR fed the HC diet, the serum cholesterol level significantly increased, but no aortic cholesterol deposition was observed. 3. The serum cholesterol level in DSR fed the HC diet markedly increased compared to that in DSR fed the basal diet, and this change was greater with the diet containing 8% NaCl than 0.4% NaCl. A significant increase in the content of aortic cholesterol, notably cholesteryl ester, was observed in only DSR fed the HC diet containing 8% NaCl. 4. These results suggest that the combination of hypercholesterolaemia with salt-induced hypertension acts as a greater risk factor for atherosclerosis than that with genetic hypertension.

Animals↗
PubMed1995

Comparison of the effects of hypercholesterolaemia on relaxation responses in aortas of spontaneously hypertensive rats and Dahl salt-sensitive rats.

1. We investigated the effects of hypercholesterolaemia on relaxation responses in thoracic aortas isolated from two different types of hypertensive rats; spontaneously hypertensive rats (SHR) and Dahl salt-sensitive rats (DSR). 2. All rats fed the high cholesterol diet for 8 weeks showed a significant increase in the serum cholesterol level. The high cholesterol diet did not change the blood pressure of SHR, but increased that of hypertensive DSR fed a high-salt diet. 3. In aortas of SHR, the high-cholesterol diet did not change the endothelium-dependent and -independent relaxation induced by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. 4. In aortas of hypertensive DSR, the high-cholesterol diet notably reduced the ACh-induced relaxations and slightly reduced SNP-induced relaxation. 5. These results suggest that hypercholesterolaemia causes greater impairment of endothelium-dependent relaxation in rat aorta with salt-induced hypertension than genetic hypertension.

Acetylcholine↗
PubMed1995

Stereotactic Gamma Knife radiosurgery for the treatment of dystonia.

A case of dystonia treated with Gamma Knife radiosurgery is reported. A 37-year-old female patient had a history of tuberculous meningitis at the age of 10 and subsequently developed a left hemidystonia. MRI showed an old infarction in the right caudate nucleus, globus pallidus and putamen. Stereotactic Gamma Knife radiosurgery was employed to make a lesion in the right posteroventral globus pallidus. Postoperatively, the patient's condition improved. However, homonymous hemianopsia developed postoperatively.

Adult↗
PubMed1995

Gamma knife radiosurgery for malignant tumors.

Between May 1990, and June 1994, 79 patients with malignant tumors were treated radiosurgically using a Leksell gamma unit at Asan Medical Center. Of these patients, 57 were metastatic brain tumor, 12 were glioblastoma multiforme (GM), 4 were primitive neuroectodermal tumor, 3 were malignant germ cell tumor, 2 were recurrent lymphoma, and 1 was adenoid cystic carcinoma of the orbit. Among 57 patients with metastatic tumors, 28 patients harboring 60 tumors were followed clinically and radiographically. The median marginal dose for these tumors was 30 Gy and the median survival rate was 15 months. Twenty-one tumors disappeared and 32 tumors decreased in size during 2 to 6 months after radiosurgery on computed tomographic or magnetic resonance imaging scans. All 12 patients with GM were treated with conventional radiation (6,240 approximately 6,500 cGy) after surgical resection or biopsy prior to radiosurgery (13 approximately 15 Gy to margin). The results were varied. Radiosurgical treatment of two recurrent lymphomas and three recurrent mixed germ cell tumors after radiation and chemotherapy provided rapid clinical improvement with disappearance of the tumor. However, new lesions appeared in two lymphomas and one mixed germ cell tumor within 3 to 4 months. One patient with adenoid cystic carcinoma of the orbit, who was treated radiosurgically prior to resection, is alive without recurrence 31 months after the treatment. Gamma knife radiosurgery appears to be the best alternative method to surgical excision plus radiation therapy for single and multiple cerebral metastases. It also provides rapid palliation of symptoms due to recurrent malignant tumors. And it may have an adjuvant role in the treatment of some tumors delaying local recurrence, if given prior to resection. However, the preliminary results for the malignant gliomas were inconclusive.

Adult↗
PubMed1994

Cerebral energy metabolism following ESWL brain injury model and effects of cerebral protective drugs.

The goal of this study was to introduce a new method inducing an experimental brain injury model using ESWL(Extracorporeal Shock Wave Lithotripsy) and to evaluate findings of localized lesions on 1H MR imaging and the response of cerebral energy metabolism using a 31P MR spectroscope to the ESWL brain injury in cats. This study also examined effects of cerebral protective drugs. 1) There were no statistically significant changes in pH at all measurement points. 2) In the trauma group, initial decrease of PCr/Pi was seen at 30 to 60 minutes with return to control levels by 2 hours after injury(P < 0.05), followed by a second decline at 4 hours which lasted until 8 hours after injury. 3) Significant recovery in PCr/Pi(P < 0.05) was observed in both the THAM and dexamethasone treated groups at all measurement points and in the mannitol treated group only temporary recovery at 30 and 60 minutes (P < 0.05). 4) High intensity signals were seen on 1H MR imaging in traumatized animals. This study demonstrated the immediate and persistent recovery of cerebral energy metabolism using THAM or dexamethasone and an immediate but transient effect with mannitol in traumatized animals.

Adenosine Triphosphate↗