Biomedical subjects

Heung-Man Lee

Publications and source records attributed to Heung-Man Lee.

12 recordsLinked to original sources

PubMed2003

Expression of cathelicidin in human salivary glands.

BACKGROUND: Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. One of the antimicrobial peptides, LL-37, is the only cathelicidin protein that has yet been identified in humans. Cathelicidins are a family of peptides thought to provide an innate defensive barrier against a variety of potential microbial pathogens. OBJECTIVES: To examine the expression of cathelicidin in human salivary glands and to investigate up-regulation of cathelicidin in inflammatory conditions. DESIGN: Reverse transcriptase-polymerase chain reaction and immunohistochemical staining were performed on 20 salivary gland tissues, 10 from normal salivary glands and 10 from glands with chronic sialadenitis. RESULTS: Cathelicidin messenger RNA transcripts were detected in the tissues from the normal salivary glands and the glands with chronic sialadenitis. The level of cathelicidin messenger RNA in glands with chronic sialadenitis was significantly increased compared with that in normal salivary glands. Cathelicidin protein was expressed in the glandular epithelium of the normal salivary glands and the glands with chronic sialadenitis. CONCLUSION: The results indicate that cathelicidin might play an important role in innate host defense of human salivary glands.

Antimicrobial Cationic Peptides↗

PubMed2003

Endoscopic removal of an intranasal ectopic tooth.

Intranasal ectopic teeth are rare and ectopic eruption of teeth can occur in a variety of locations. Commonly seen in the palate and maxillary sinus, they have also been reported in the mandibular condyle, coronoid process, orbital and nasal cavities, and through the skin. With the advent of sinonasal endoscopy in the mid 1980s, and subsequent advances in surgical techniques, endoscopic management of intranasal lesions has become possible. In the current case study, we report a successful endoscopic removal of intranasal ectopic teeth located in the nasal cavity. The endoscopic surgical approach used in this case caused less morbidity than do the more common methods of removing an intranasal ectopic tooth.

Endoscopy↗

PubMed2003

Antimicrobial peptide LL-37 is upregulated in chronic nasal inflammatory disease.

OBJECTIVE: LL-37 is one of the antimicrobial peptides and the only member of the cathelicidin family identified so far in humans. We attempted to find a correlation between LL-37 peptide and inflammation of the nasal mucosa. MATERIAL AND METHODS: Nasal mucosa specimens were obtained from 15 chronic infective rhinitis patients and 6 normal controls. Immunohistochemical staining was used to examine the localization of LL-37 and reverse transcriptase polymerase chain reaction (RT-PCR) was used to determine the levels of LL-37, IL-1beta and IL-8 in tissue. RESULTS: LL-37 peptide was primarily localized in the surface of the epithelia, in the serous and mucous cells of the submucosal glands and in stromal inflammatory cells. The number of LL-37 immunoreactive cells in inflammatory nasal mucosa was significantly increased compared with normal nasal tissue. Using RT-PCR, LL-37 mRNA was detected in 3/6 normal turbinate samples but in all cases with inflammatory nasal tissues. IL-1beta and IL-8 transcripts exhibited a similar pattern to that of LL-37. CONCLUSIONS: We suggest that LL-37 is one of the antimicrobial peptides found in human nasal mucosa and that it participates in the innate immune system of the nasal mucosa.

Adult↗

PubMed2003

Expression of epidermal growth factor receptor and its ligands in chronic sinusitis.

The epidermal growth factor receptor (EGF-R) system plays a crucial role in mucus production in vitro and in rats. However, the role of the EGF-R system in humans is not known. We compared the localization of EGF-R and its ligands (epidermal growth factor and transforming growth factor alpha) in the epithelia of sinuses with chronic sinusitis and in those of healthy controls. Immunohistochemical techniques were employed to identify the presence of EGF-R and its ligands in the sinus mucosa. We found EGF-R in goblet cells, basal cells, and submucosal gland cells, but not in ciliated cells. Immunoreactivity for both epidermal growth factor and transforming growth factor alpha was found in the epithelial cells and inflammatory cells and in some submucosal gland cells. There was stronger staining of EGF-R and its ligand proteins in chronic sinusitis specimens than in controls. The interrelated localization of EGF-R and its ligands suggests a role in mucus production in the epithelium of the sinus mucosa.

Adult↗

PubMed2002

Recurrent plunging ranula treated with OK-432.

A 36-year-old man was admitted who had a 2-month history of swelling of the right submandibular area and the right side of the mouth floor. He had undergone operations for right plunging ranula with a lesion on the floor of the mouth twice 7 years ago. Under fluoroscopic guidance, the contents of the cyst were aspirated as much as possible and injected with the same amount of OK-432 solution (Picibanil 0.1 mg; 10 ml) twice with 3-week intervals. Examination after 6 weeks showed that the cystic mass seen before therapy had disappeared completely, and no recurrence was encountered after 1 year. We here report a case in which a successful sclerotherapy with OK-432 for recurrent plunging ranula after surgery was performed.

Adult↗

PubMed2002

Dual ectopic thyroid.

Ectopic thyroid is an uncommon embryological aberration characterized by the presence of thyroid tissue in a site other than in its usual pre-tracheal region. It occurs along the path of descent of the developing thyroid primodium from the foramen cecum. It most commonly presents itself as a lingual thyroid and is the only thyroid in 70% of all cases. It is extremely rare for two ectopic foci of thyroid tissue to be present simultaneously. The authors report a recent case of dual ectopic thyroid present in the lingual and infrahyoid areas with no thyroid tissue in the pre-tracheal area in a 15-year-old girl. The patient had originally been scheduled for surgery under the impression of thyroglossal duct cyst; however, a pre-operative computed tomography scan of neck and thyroid scans revealed the presence of dual ectopic thyroid, thus preventing unnecessary surgery. Therefore, thyroid scan, along with either neck CT or neck ultrasonogram, should be performed routinely to avoid unnecessary surgery if the clinical picture is at all compatible with thyroid ectopia.

Adolescent↗

PubMed2002

Hypoxia induces mitochondrial DNA damage and stimulates expression of a DNA repair enzyme, the Escherichia coli MutY DNA glycosylase homolog (MYH), in vivo, in the rat brain.

Hypoxia-associated, acutely reduced blood oxygenation can compromise energy metabolism, alter oxidant/antioxidant balance and damage cellular components, including DNA. We show in vivo, in the rat brain that respiratory hypoxia leads to formation of the oxidative DNA lesion, 8-hydroxy-2'-deoxyguanosine (oh8dG), a biomarker for oxidative DNA damage and to increased expression of a DNA repair enzyme involved in protection of the genome from the mutagenic consequences of oh8dG. The enzyme is a homolog of the Escherichia coli MutY DNA glycosylase (MYH), which excises adenine residues misincorporated opposite the oxidized base, oh8dG. We have cloned a full-length rat MYH (rMYH) cDNA, which encodes 516 amino acids, and by in situ hybridization analysis obtained expression patterns of rMYH mRNA in hippocampal, cortical and cerebellar regions. Ensuing hypoxia, mitochondrial DNA damage was induced and rMYH expression strongly elevated. This is the first evidence for a regulated expression of a DNA repair enzyme in the context of respiratory hypoxia. Our findings support the premise that oxidative DNA damage is repaired in neurons and the possibility that the hypoxia-induced expression of a DNA repair enzyme in the brain represents an adaptive mechanism for protection of neuronal DNA from injurious consequences of disrupted energy metabolism and oxidant/antioxidant homeostasis.

Animals↗

PubMed2002

Rat MYH, a glycosylase for repair of oxidatively damaged DNA, has brain-specific isoforms that localize to neuronal mitochondria.

Mitochondrial genomes are exposed to a heavy load of reactive oxygen species (ROS) that damage DNA. Since in neurons, mitochondrial DNA integrity must be maintained over the entire mammalian life span, neuronal mitochondria most likely repair oxidatively damaged DNA. We show that the Escherichia coli MutY DNA glycosylase homolog (MYH) in rat (rMYH) involved in repair of oxidative damage is abundantly expressed in the rat brain, with isoforms that are exclusive to brain tissue. Confocal microscopy and western analyses reveal localization of rMYH in neuronal mitochondria. To assess involvement of MYH in the neuronal response to oxidative DNA damage, we used a rat model of respiratory hypoxia, in which acutely reduced blood oxygenation leads to generation of superoxide, and formation and subsequent removal of 8-hydroxy-2'-deoxyguanosine (8OHdG). Removal of 8OHdG is accompanied by a spatial increase in rMYH immunoreactivity in the brain and an increase in levels of one of the three mitochondrial MYH isoforms, suggesting that inducible and non-inducible MYH isoforms exist in the brain. The mitochondrial localization of oxidative DNA damage repair enzymes in neurons may represent a specialized neuronal mechanism that safeguards mitochondrial genomes in the face of routine and accidental exposures to heavy loads of injurious ROS.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2002

Endoscopic endonasal reconstruction of blowout fractures of the medial orbital walls.

High-resolution endoscopes and the advent of endoscopic instruments for sinus surgery currently provide surgeons with excellent endonasal visualization and access to the medial orbital walls. The purpose of this study was to demonstrate the reduction of medial orbital wall fractures through an endonasal endoscopic approach that allows the repair of the medial orbital wall fractures without an external incision. This study was a retrospective analysis of 16 patients who underwent surgical repair of medial orbital wall fractures from March of 1997 to May of 1998. The 11 male and five female patients ranged in age from 16 to 54 years (mean, 30.5 years). These patients had undergone primary reduction of medial orbital wall fractures and were observed for at least 12 months after surgery. There were no intraoperative or postoperative complications. Fifteen of 16 patients showed a complete improvement of their symptoms. One patient showed persistent diplopia, which was well managed by prisms. Endoscopic reduction of medial orbital wall fracture using an endonasal approach seems to produce good results and definite cosmetic advantages.

Adolescent↗

PubMed2002

Ghrelin, a new gastrointestinal endocrine peptide that stimulates insulin secretion: enteric distribution, ontogeny, influence of endocrine, and dietary manipulations.

Ghrelin, an endogenous ligand for the GH secretagogue receptor was characterized recently from extracts of rat stomach. We describe the enteric distribution of ghrelin, ontogeny of stomach ghrelin gene expression, effects of dietary and endocrine manipulations, and vagotomy on stomach ghrelin mRNA and peptide levels and secretion in the rat. Ghrelin expression was examined by Northern blotting. Tissue and plasma ghrelin levels were measured by RIA. A gradient of ghrelin production occurs in the rat gastrointestinal tract with the highest ghrelin expression and peptide levels in the mucosal layer of the stomach-fundus and the lowest levels in the colon. Ghrelin was not detectable in the fetal stomach and increased progressively after birth especially during the second and third postnatal weeks. Plasma ghrelin levels also increased in parallel with stomach ghrelin levels postnatally. Exogenous GH treatment decreased stomach ghrelin expression significantly. A high-fat diet decreased plasma ghrelin levels, whereas a low-protein diet increased plasma ghrelin levels significantly. Intravenous administration of ghrelin stimulates gastrin and insulin secretion. Our findings indicate that ghrelin is an important stomach hormone sensitive to nutritional intake; ghrelin may link enteric nutrition with secretion of GH, insulin, and gastrin.

Animal Feed↗

PubMed2002

Rationale for osteotome selection in rhinoplasty.

Proper selection of an osteotome for nasal osteotomy is important for minimizing soft tissue trauma. Radiographic analysis of the facial bony lateral wall thickness was performed to suggest a guideline for an appropriate osteotome size for Asians. Facial bone computed tomography (CT) of 100 patients (50 male, 50 female) were studied. The thickness of the facial bony lateral wall at three points along the track of a lateral osteotomy, and two points along the track of a medial osteotomy and intermediate osteotomy were measured. The average bony thickness along the track of a lateral osteotomy was 2.61 +/- 0.66 mm at the low level, 2.75 +/- 0.76 mm at the middle level, and 2.72 +/- 0.53 mm at the high level in subjects. The average bony thickness along the track of an intermediate osteotomy were 1.26 +/- 0.34 mm at the low level, and 1.31 +/- 0.32 mm at the high level in the subjects. The average bony thickness along the track of the medial osteotomy were 2.54 +/- 0.31 mm at the low level, and 2.77 +/- 0.30 mm at the high level in subjects. These results may provide a guideline for choosing an osteotome of appropriate size for the Asian population.

Adult↗

PubMed2002

Nasolabial cyst: a retrospective analysis of 18 cases.

Nasolabial cysts are rare but easily identifiable when they do occur. They are thought to arise from the remnants of the nasolacrimal ducts, but most of the available information on these cysts is limited to isolated case reports. The purpose of our study was to examine the clinical and pathologic features of nasolabial cysts in order to provide a basis for their correct diagnosis and treatment. Eighteen patients with nasolabial cysts were treated at Korea University's Guro Hospital between Jan. 1, 1988, and Dec. 31, 1999. We retrospectively analyzed the clinical appearance, pathologic findings, and treatment results in each case. All patients underwent surgery via the sublabial approach. The lining epithelia were identified as either pseudostratified, stratified squamous, or simple cuboidal. A cyst recurred in only one case, and there were no surgical complications on follow-up. The results of our study provide a basis for sound diagnosis and treatment.

Adolescent↗