PubMed Health⌕ Search

Biomedical subjects

H C Park

Publications and source records attributed to H C Park.

At least 19 recordsLinked to original sources
PubMed2007

Toluene-induced accumulation of trehalose by Pseudomonas sp. BCNU 106 through the expression of otsA and otsB homologues.

AIM: The objective of this study was to investigate toluene-induced accumulation mechanism of trehalose in a toluene-tolerant bacterium Pseudomonas sp. BCNU 106. METHODS AND RESULTS: The accumulation of trehalose by a toluene-tolerant bacterium Pseudomonas sp. BCNU 106 was examined at various cultivation time by measuring the total intracellular trehalose content, trehalase activity and mRNA levels of the trehalose-biosynthetic genes. The pattern of trehalose accumulation corresponded to the mRNA expression pattern of the trehalose-biosynthetic genes with the maximum level at 12 h or 4 h of cultivation with 10% (v/v) toluene, respectively. The trehalose-biosynthetic genes were also cloned and sequenced. Furthermore, the effects of toluene addition on the intracellular osmotic pressure and pH were investigated. It was shown that homeostasis was maintained in the bacterial cells. CONCLUSIONS: In a toluene-tolerant bacterium Pseudomonas sp. BCNU 106, a significant amount of trehalose was accumulated through the toluene-induced expression of the trehalose-biosynthetic genes after the exposure to toluene. SIGNIFICANCE AND IMPACT OF THE STUDY: The accumulation of the high level of intracellular trehalose was preceded by the expression of otsA/B genes in toluene-tolerant bacteria, contributing to the elucidation of the tolerance mechanism.

Gene Expression Regulation, Bacterial↗
PubMed2001

Cold accumulation of SCOF-1 transcripts is associated with transcriptional activation and mRNA stability.

Cold acclimation enhances the transcription of several cold regulated (COR) genes. However, little is known about whether the elevation of the transcriptional level of the COR genes is due to transcriptional activation, or mRNA stability by a low temperature. Recently, we cloned a novel cold-inducible zinc finger protein gene from soybean, SCOF-1, which may function as a positive regulator of the COR gene expression . Here we report that the elevation of the SCOF-1 transcript level by cold stress is associated with both transcriptional activation and post-transcriptional mRNA stability under a low temperature. A nuclear run-on assay reveals that cold acclimation elevates the SCOF-1 transcript about three-fold compared to that of non-acclimated soybean nuclei. Furthermore, SCOF-1 transcripts increased substantially by a low temperature in transgenic tobacco plants that constitutively expressed SCOF-1 under the control of a constitutive cauliflower mosaic virus (CaMV) 35S promoter. When a transcription inhibitor, cordycepin, was treated with the deacclimating soybean cell, the decay level of the SCOF-1 transcripts was delayed significantly. This suggests that it may affect de novo protein synthesis, which degrades the SCOF-1 mRNA at room temperature. In addition, a secondary structure may be involved in the mRNA stability of SCOF-1 under a low temperature.

Acclimatization↗
PubMed2001

Anterior cervical corpectomy and fusion using miniplate and screws in a 7-year-old child with eosinophilic granuloma of the cervical spine.

STUDY DESIGN: This is a case report of a 7-year-old child with eosinophilic granuloma in the cervical spine, which underwent anterior cervical corpectomy and fusion by using Miniplate and screws. OBJECTIVES: To describe the use of Miniplate and screws for pediatric cervical anterior fusion. SUMMARY OF BACKGROUND DATA: Eosinophilic granuloma is a rare disease causing destructive bony lesions of the cervical spine in children. A complete resection and fusion were considered to be the preferable treatment in our case. However, cervical spinal fusion and instrumentation in children may be technically difficult because of the size of the vertebral body and the iliac bone. In addition, a proper device for an internal fixation in pediatric patients is not yet available. METHODS: A case of eosinophilic granuloma in pediatric spine was presented. RESULTS: We confirmed successful bony fusion and the restoration of the normal cervical curvature without recurrence of the tumor 2 years after the procedure. CONCLUSIONS: For proper internal fixation and prevention of dislodgement of the grafted bone, we used the Miniplate and screws as internal fixator after intralesional resection of the tumor mass.

Bone Plates↗
PubMed2001

A more basal approach in microvascular decompression for hemifacial spasm: the para-condylar fossa approach.

BACKGROUND: In view of the fact that a basal craniectomy in microvascular decompression (MVD) for hemifacial spasm (HFS) can minimize cerebellar retraction and expose the facial nerve root exit zone (FNREZ) directly from below without placement of tension on the seventh-eighth cranial nerve complex, we used a more basal approach in 32 patients with typical HFS. METHOD: A slightly curved skin incision 5 cm in length and 2 cm posterior and parallel to the mastoid notch was made. The basal lateral occipital plate including the lateral one-fourth of the condylar fossa and the posterior one-fourth of the jugular process were removed. For the early drainage of cerebrospinal fluid through a small dural hole, the basal occipital plate posteromedial to the condylar fossa was removed. With this basal craniectomy, minimum elevation of the cerebellar tonsil and flocculus could expose FNREZ safely. FINDINGS: Thirty one of 32 patients displayed complete disappearance of spasm following surgery. One patient showed 70% decrease of spasm. Delayed transient facial weakness occurred in one patient. Audiometries showed no postoperative hearing decrease in any patient, even though no intra-operative monitoring of the cochlear function was undertaken. INTERPRETATION: Although this basal approach, the para-condylar fossa approach, is a slightly basal modification of the conventional procedure, it may minimize complications.

Adult↗
PubMed2001

Combined chemotherapy and radiation versus radiation alone in the management of localized angiocentric lymphoma of the head and neck.

BACKGROUND AND PURPOSE: To clarify the clinical benefit derived from the combined modality therapy (CMT) comprised of chemotherapy and involved-field radiotherapy (XRT) for stage I and II angiocentric lymphomas of the head and neck. MATERIAL AND METHODS: Of 143 patients with angiocentric lymphoma of the head and neck treated at the Yonsei Cancer Center between 1976 and 1995, 104 patients (XRT group) received involved-field XRT alone with a median dose of 50.4 Gy (range: 20-70 Gy), while 39 patients (CMT group) received a median three cycles (range: 1-6 cycles) of chemotherapy before starting involved-field XRT. The response rate, patterns of failure, complications, and survival data of the XRT group were compared with those of the CMT group. RESULTS: Despite a higher response rate, local failure was the most common pattern of failure in patients of the both groups. The patterns of failure, including the systemic relapse rate were not influenced by the addition of combination chemotherapy. Although both modalities were well tolerated by the majority of patients, aberrant immunologic disorders or medical illnesses, such as a hemophagocytic syndrome, sepsis, intractable hemorrhage, or the evolution of second primary malignancies were more frequently observed in patients of the CMT group. The prognosis of patients in the XRT group was relatively poor, with a 5-year overall actuarial survival rate of 38% and disease-free survival rate of 32%, respectively. However, their clinical outcome was not altered by the addition of systemic chemotherapy. Achieving complete remission was the most important prognostic factor on univariate and multivariate analyses, but treatment modality was not found to be a prognostic variable influencing survival. CONCLUSIONS: Involved-field XRT alone for angiocentric lymphoma of the head and neck was insufficient to achieve an improved survival rate, but the combination of chemotherapy and involved-field XRT failed to demonstrate any therapeutic advantage over involved-field XRT alone.

Adolescent↗
PubMed2001

Endoscopic transsphenoidal approach through a widened nasal cavity for pituitary lesions.

We operated upon 12 patients with macroadenoma and two with Rathke's cleft cyst using an endoscope through a nasal speculum. Pure endoscopic endonasal transsphenoiolal approach (TSA) was performed in nine patients and endoscope-assisted microscopic endo nasal TSA in five. A thin-bladed nasal speculum was used to achieve a wide, almost midline, pathway without an incision at the septal mucosa. This made it possible to convert from the endoscopic to the microscopic approach and vice versa at any time during operation as the occasion demanded. In 10 of the 12 patients with macroadenoma, adenomas were removed totally and did not recur during the mean follow-up period of 24 months. Two adenomas could not be removed totally due to their invasiveness. In two of five patients who underwent endoscope-assisted microscopic TSA for macroadenoma, the endoscope could visualise residual tumour at blind corners after microscopic tumor removal. Two patients with Rathke's cleft cyst did not show recurrence. No patient showed sinonasal or endocrinological complications. Versatile use of the endoscope through a widened nasal cavity using a nasal speculum is a promising tool for the treatment of pituitary lesions.

Adenoma↗
PubMed2001

Successful treatment of Boerhaave's syndrome with endoscopic insertion of a self-expandable metallic stent: report of three cases and a review of the literature.

Boerhaave's syndrome is a rare but life-threatening condition which presents a diagnostic as well as therapeutic challenge. Early diagnosis and prompt surgical repair are critical for survival; however late recognition of esophageal rupture is not unusual. A variety of nonsurgical approaches have been proposed, particularly in the case of delayed diagnosis. In recent years, the insertion of a metallic stent has been described as a promising modality in the treatment of spontaneous esophageal rupture. We report three cases of Boerhaave's syndrome treated with self-expandable metallic stents and review previously published cases.

Esophageal Diseases↗
PubMed2001

Self-expanding coil stent with a long delivery system for palliation of unresectable malignant gastric outlet obstruction: a prospective study.

BACKGROUND AND STUDY AIMS: Peroral intubation of a self-expanding metal stent is usually difficult in patients with unresectable malignant gastric outlet obstruction, because the delivery systems currently available are not long enough and cannot easily pass the angulated gastroduodenal structure. We carried out a prospective study to assess the efficacy of a coil stent with a newly developed long delivery system, for palliation of unresectable malignant gastric outlet obstruction. PATIENTS AND METHODS: In 29 patients with unresectable malignant gastric outlet obstruction, caused by gastric cancer (26 patients), pancreatic head cancer (two patients), or duodenal cancer (one patient), peroral intubation of a self-expanding nickel-titanium coil stent was attempted, using a lengthened delivery system of 150 cm, under endoscopic and fluoroscopic guidance. RESULTS: Management was successful in 26 of 29 patients (89.7 %) without immediate major complications. In one patient in whom peroral intubation failed, percutaneous intubation of the coil stent via percutaneous endoscopic gastrostomy was done. After insertion of the coil stent, food ingestion with symptomatic improvement with regard to vomiting was achieved in 26 of 27 patients (96.3 %), including the patient with percutaneous stent insertion. During the follow-up period, dysphagia and Karnofsky scores improved significantly. Stent migration occurred in two patients, and tumor ingrowth in another two; re-intervention was done successfully performed in two instances. The mean survival time was 124 days (range 34 - 310 days) in the 22 patients who had no need for re-intervention during follow-up; among these was a patient who experienced stent occlusion by food material, which was easily corrected with endoscopic flushing. CONCLUSIONS: Peroral intubation of a self-expanding coil stent using a long delivery system is a safe and effective palliative technique for unresectable malignant gastric outlet obstruction, and significantly improves the quality of life of patients.

Adult↗
PubMed2001

A feasibility study using three-dimensional conformal boost technique in locally advanced carcinoma of the nasopharynx.

To investigate the feasibility and efficacy of dose escalation using three-dimensional (3-D) conformal boost technique, 21 patients with stage III or IV nasopharyngeal cancer were enrolled in a prospective protocol. All patients with node metastases initially received external radiotherapy by conventional technique up to 70.2 Gy, followed by 3-D conformal radiotherapy (3-D CRT) to the boost part up to 79.2 Gy with 9 Gy increments (daily fraction of 1.8 Gy for 5 days). A modified technique with the same dose escalation of 9 Gy using 3-D CRT was applied to 7 patients without node metastases, who were treated by conventional technique up to 54 Gy, followed by 3-D CRT to boost up to a basic dose of 70.2 Gy, and then finally with dose escalation of 9 Gy. The protocol was relatively well tolerated by the majority of patients. Acute complications during the dose escalation schedule was low, with rare occurrences of grade 3 or 4 toxicity. Although late radiation-induced complications also appeared limited, 1 patient developed a temporal lobe necrosis and 2 patients suffered from sensory-neural hearing loss. There were no radiation-induced fatal complications. At a median follow-up of 48 months, only 3 patients experienced local failure and 2 patients developed distant metastases. The 5-year overall actuarial survival rate and recurrence-free survival rate for all patients were 68% and 85%, respectively. On the basis of acceptable morbidity and encouraging treatment results, we conclude that the dose escalation in 9 Gy increments using a 3-D conformal boost technique is relatively safe and efficacious, enough to be used routinely for locally advanced nasopharyngeal cancers.

Adult↗
PubMed2001

Atypical bone metastasis and radiation changes in a colon cancer: a case report and a review of the literature.

We report a unique case of skeletal metastasis with prominent soft tissue extension from a colon cancer in a 44-year-old male patient. Four years after the diagnosis of colon cancer, plain radiographic examinations revealed a prominent soft tissue mass associated with cortical destruction of the right femur. Palliative radiotherapy of the right femur was performed. After completing radiotherapy, massive remineralization was seen in the soft tissue component. With the assistance of pre- and post-radiotherapy computerized tomography images, obtained in the process of planning the radiotherapy, we reached the conclusion that in our case the pre-radiotherapy finding was an extreme case of eccentric expansion of the bony cortex due to the outgrowth of bony metastasis. Retrospectively, the initial prominent soft tissue mass associated with the cortical destruction seems to have been a protruding bone metastasis, extending from the medial aspect of the right femur. This peculiar feature with remineralization after radiotherapy should help explain the phenomenon of atypical bony metastasis from a radiological perspective.

Adenocarcinoma↗
PubMed2001

Acid secretion from a heterotopic gastric mucosa in the upper esophagus demonstrated by dual probe 24-hour ambulatory pH monitoring.

Heterotopic gastric mucosa in the upper esophagus is frequently found during endoscopic examination. Although most patients with heterotopic gastric mucosa of the upper esophagus, referred as inlet patch, are asymptomatic, symptomatic patients with complications resulting from this ectopic mucosa have also been reported. Acid secretion by the inlet patch has been suggested in some reports. We report a case of heterotopic gastric mucosa in the upper esophagus, with secretion of acid, demonstrated by continuous ambulatory pH monitoring, and the improvement of pharyngeal symptoms after the use of a proton pump inhibitor.

Adult↗
PubMed2001

Clinical outcome in continuous ambulatory peritoneal dialysis patients is not influenced by high peritoneal transport status.

OBJECTIVES: We undertook this study to examine the influence of demographics, peritoneal membrane transport characteristics, nutrition indices, dialysis adequacy, and comorbid diseases on patient survival on continuous ambulatory peritoneal dialysis (CAPD), and to identify whether high peritoneal membrane transport is an independent risk factor for mortality on CAPD. DESIGN: Our retrospective study was carried out in CAPD patients in a large tertiary care teaching hospital. METHODS: Until December 2000, we followed 212 patients who started CAPD between 1994 and 1997 and who underwent a peritoneal equilibration test (PET) within 3 months of CAPD initiation. RESULTS: By univariate analysis, comorbid diseases, old age, high peritoneal transport, and serum albumin predicted patient mortality. Independent predictors of mortality as determined by the Cox proportional hazard model included diabetes mellitus, cardiovascular disease, serum albumin, and old age. High peritoneal transport failed to independently influence mortality in our CAPD patients.

Adult↗
PubMed2000

Analysis of upstream elements in the HuC promoter leads to the establishment of transgenic zebrafish with fluorescent neurons.

HuC encodes an RNA binding protein homologous to Drosophila elav that serves as an excellent early marker for differentiating neurons. We have characterized the promoter of the zebrafish HuC gene by examining the ability of 5'-upstream fragments to drive expression of green fluorescent protein (GFP) in live embryos. We determined that 2.8 kb of the 5'-flanking sequence is sufficient to restrict GFP gene expression to neurons. The core promoter spans 251 base pairs and contains a CCAAT box and one SP1 sequence but no TATA box is present near the transcription start site. A putative MyT1 binding site and at least 17 E-box sequences are necessary to maintain the neuronal specificity of HuC expression. Interestingly, sequential removal of the putative MyT1 binding site and 14 distal E boxes does not appear to abolish neuronal expression; rather, it leads to a progressive expansion of GFP expression into muscle cells. Further removal of the three proximal E boxes eliminates neuronal and muscle specificity of GFP expression and leads to ubiquitous expression of GFP in the whole body. Identification of key components of the HuC promoter has led to the establishment of a stable zebrafish transgenic line (HuC-GFP) in which GFP is expressed specifically in neurons. We crossed mind bomb (mib) fish with this line to visualize their neurogenic phenotype in live mib(-/-) mutant embryos. This cross illustrates how HuC-GFP fish could be used in the future to identify and analyze zebrafish mutants with an aberrant pattern of early neurons.

Animals↗
PubMed2000

Local radiotherapy for unresectable hepatocellular carcinoma patients who failed with transcatheter arterial chemoembolization.

PURPOSE: The purpose of this study was to investigate the efficacy of local radiotherapy (RT) as a salvage treatment for unresectable hepatocellular carcinoma (HCC) patients who failed with transcatheter arterial chemoembolization (TACE). METHODS AND MATERIALS: Patients with unresectable HCC who had been treated with and eventually failed with TACE were eligible. The judgment of TACE failure was based on incomplete tumor filling of lipiodol-adriamycin mixture on either angiography or computed tomography (CT) scan. From January 1993 to December 1997, 27 patients were entered into this study. They had UICC Stage III (17) or IVA (10) disease, with a mean tumor size of 7.2 +/- 2.9 cm. Local RT was done, with a mean tumor dose of 51.8 +/- 7.9 Gy, in daily 1.8-Gy fractions using a 10- or 6-MV linear accelerator. Survival was calculated from both the diagnosis and the start of RT using the Kaplan-Meier method. RESULTS: An objective response was observed in 16 of 24 patients (66.7%) including 1 CR. Intrahepatic metastasis was noted outside the RT field in 10 patients (37.0%). Extrahepatic distant metastasis occurred in 4 patients. Survival rates at 1, 2, and 3 years were 85. 2%, 58.1%, and 33.2%, respectively, from the diagnosis and 55.9%, 35. 7%, and 21.4%, respectively, from the start of RT. The median survivals were 26 months from the diagnosis and 14 months from the start of RT. Acute toxicity involved alteration in liver function test (13 patients) and thrombocytopenia (2 patients). Subacute and chronic toxicity involved gastroduodenal ulcer (3 patients) and duodenitis (2 patients). There was no treatment-related death. CONCLUSION: In unresectable HCC patients who failed with TACE, local RT induced a substantial tumor response of 66.7%, with a 3-year survival rate of 21.4% and a median survival time of 14 months. Toxicity was significant but manageable. Although we do not know if there is survival benefit through this treatment, local RT in these patients seems to be valuable as a salvage for TACE-failed HCC.

Adult↗
PubMed2000

Structural comparison of zebrafish Elav/Hu and their differential expressions during neurogenesis.

The present communication reports the isolation and characterization of three new zebrafish elav/Hu (Kim, C.-H., Ueshima, E., Muraoka, O., Tanaka, H., Yeo, S.-Y., Huh, T.-L. and Miki, N., Zebrafish elav/HuC homologue as a very early neuronal marker. Neurosci. Lett., 216 (1996) 109-112) homologues, HuA, HuD and HuG. While HuA and HuG showed weak and ubiquitous expressions, HuD, as well as HuC, were specifically expressed in the neuronal cells. The first expression of HuD was detectable of the 10-somite stage, that is, several hours later than HuC. After 24 h of embryonic development, although HuD and HuC expressions overlapped overall, the cells expressing HuD were restricted to subsets of the HuC-positive neuronal cells in the brain and spinal cord. These differentially regulated spatial and temporal expression patterns implied distinct roles for HuC and HuD in neuronal determination and neuronal differentiation, respectively.

Amino Acid Sequence↗
PubMed2000

Spinal clear cell meningioma presented with progressive paraparesis in infancy.

Clear cell meningioma, about 20 cases of which have been reported in the literature, is a morphological variant of meningioma. The authors report a case of spinal clear cell meningioma that occurred in a child. A 14-month-old girl showed gradually progressive paraparesis 1 month after she started to walk. Magnetic resonance image showed an intradural extramedullary mass compressing the conus medullaris and cauda equina. Complete excision of the tumor was done, and the patient gradually recovered from motor weakness and neurogenic bladder. Histological examinations along with immunohistochemical and ultrastructural investigations allowed a diagnosis of clear cell meningioma. During the follow-up period, a recurrent mass lesion was detected on the 8-month follow-up MR image in the same region. Because clear cell meningioma might be biologically aggressive, postoperative adjuvant therapy and close follow-up investigation should be considered.

Female↗