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Biomedical subjects

J M Hong

Publications and source records attributed to J M Hong.

17 recordsLinked to original sources
PubMed2006

Association of PLXNA2 polymorphisms with vertebral fracture risk and bone mineral density in postmenopausal Korean population.

INTRODUCTION: Plexin A2 (PLXNA2) is a receptor that recognizes secreted or membrane-bound semaphorin 3A, which is implicated in neural regulation of bone metabolism. MATERIALS AND METHODS: In the present study, we identified 48 genetic polymorphisms in PLXNA2 by resequencing, and 10 single nucleotide polymorphisms (SNPs) were selected for further investigation into their potential involvement in osteoporosis in a postmenopausal population (n=560). RESULTS: Two SNPs, +14G>A (Gln5Arg) and +183429C>T (Tyr1621Tyr), and Block1-ht2 were associated with risk of vertebral fracture (p=0.01-0.05), and three SNPs, +799G>A (Ala267Thr), +135391G>A, and +190531G>C, were associated with bone mineral density at various femur sites (p=0.003-0.03). Particularly, the minor allele of +14G>A was associated with a protective effect on vertebral fracture and higher lumbar bone mineral density, suggesting that +14G>A may be a useful marker for osteoporosis and its related fracture. CONCLUSION: These results provide, for the first time, evidence supporting the association of PLXNA2 with osteoporosis in postmenopausal women.

Aged↗
PubMed2000

Glandular odontogenic cyst: a case report.

Glandular odontogenic cyst (GOC) is an extremely rare lesion occurring in the jawbones. Sialo-odontogenic cyst was first described as a multicystic lesion resembling a botryoid odontogenic cyst (BOC) or a central mucoepidermoid carcinoma by Padayachee in 1987. In 1988, Gardner used the term "glandular odontogenic cyst" and considered it as a histologic variant of BOC. Most authors agreed that GOC was odontogenic because of the concurrent ball-like epithelial structure, ameloblastoma, squamous odontogenic tumor-like proliferation in its wall, or hyaline bodies in the epithelium lining. Recently, immunohistochemical studies of the cytokeratin profiles have also supported this concept. Its aggressive behavior and the recurrent tendency make it important. A new case of GOC in a 59-year-old male presented as a multilocular radiolucency in the anterior region of the mandible, invading the marrow space by epithelial islands is described with other clinicopathologic features and the literature is briefly discussed.

Humans↗
PubMed1999

Effect of liposomes on mineralization in rat osteoblast-enriched cultures.

Liposomes, artificial membranous lipid vesicles, have been used as model structures for biological calcification processes. However, there is no definite conclusion that liposomes can be like matrix vesicles for inducing bone calcification and bone-like tissue formation on primary cultured cells. To determine whether liposomes can promote bone cell growth and mineralization by inducing crystal nucleation, liposomes composed of egg phosphatidylcholine, cholesterol, and bovine brain phosphatidylserine were added to 21-day-old Sprague-Dawley fetal rat calvarial cell cultures from day 1. The aims were to observe proliferation and the phenotype of osteoblasts by measuring cell numbers and alkaline phosphatase (ALP) activity and, when added at confluence, to observe calcification. The data were analyzed with two-way ANOVA. During the 16-day culture period, cell numbers were not significantly affected by liposomes (100 mumol/L). However, ALP activity was significantly inhibited by liposomes (p < 0.05) at day 16 and thereafter. Calcified particles were detected by von Kossa's method, and were larger and more abundant (p < 0.05) in the liposomes groups than in the control from days 12-24. This response depended on liposomes dose. These findings suggest that liposomes promote calcification and accelerate the formation of bone-like tissue. Liposomes slightly reduce the expression of the osteoblast phenotype and do not affect cell growth in primary rat osteoblast-enriched cultures.

Alkaline Phosphatase↗
PubMed1995

Mandibular arteriovenous malformation diagnosed by MR and MRA: a case report.

A case of mandibular arteriovenous malformation (AVM) is presented. Prompt diagnosis and appropriate management are essential due to massive bleeding or even death after dental extraction or biopsy. Angiography remains the gold standard in detecting the lesion. Magnetic resonance (MR) imaging with spin-echo sequences reveals the vascular malformation as signal-void. MR angiography can demonstrate the nidus, dilated artery and vein. MR imaging and MR angiography can supplement angiography in the diagnosis of mandibular AVM.

Arteriovenous Malformations↗
PubMed1989

Quantitative evaluation of proximal contacts in posterior composite restorations. Part I. Methodology.

An in vivo method of quantitative measuring intertooth distance before and after placement of a Class 2 composite resin restoration has been developed. A Kaman Sciences KD-2611 non-contact displacement measuring system with a 1 U unshield sensor, based upon the variable resistance of eddy current, was used for the intraoral measurement. Quantitative evaluation of proximal wear, therefore, can be made preoperatively, postoperatively, and at subsequent recall interval for posterior composite resin restorations.

Composite Resins↗
PubMed1988

The effect of recasting on the oxidation layer of a palladium-silver porcelain alloy.

The oxidation zone of a commercial palladium-silver porcelain alloy was compared after repeated casting with and without the addition of new alloy. The intensity of palladium, silver, tin, indium, and O K-alpha near the oxidation zone was analyzed with XMA. The intensity curves of tin, silver, and oxygen increased progressively through each generation despite the addition of new alloy. The thickness of the oxidation zone and the microporosities at the internal oxidation zone increased through each generation without the addition of new alloy. Although the findings indicated that the oxidation zone was favorably formed by adding new alloy, 50% by weight, for four generations, the silver and metallic oxides of the oxidation zone increased through each generation. The reuse of the palladium-silver porcelain alloy remains questionable.

Dental Alloys↗
PubMedDate not supplied

Surgical management of dyslipidemia: clinical and experimental evidence.

Coronary artery disease (CAD) is still a major cause of mortality in developed countries, and dyslipidemia is one of its major causes. In an attempt to reduce both mortality and morbidity from CAD, several dietary, pharmacological, and surgical approaches have been used to reduce plasma cholesterol levels. In this brief review, we summarize the evidence for cholesterol-lowering effects and safety of partial ileal bypass (PIB) procedure in both human and animal studies. The results of the Program on the Surgical Control of the Hyperlipidemias (POSCH), which involved a total of 838 subjects with myocardial infarction, are promising. A 5-year follow-up of this study revealed significant reductions of up to 27% in total cholesterol (TC) and up to 42% in low-density lipoprotein (LDL) cholesterol levels along with an increase of up to 8% in high-density lipoprotein (HDL) cholesterol levels as compared to controls. These changes were associated with other benefits such as increased HDL/TC and HDL/LDL ratios, and a significant decrease in apolipoprotein (apo) B100 and increase in apo AI levels. Similar results were also demonstrated by other studies. PIB surgery is one of the most effective methods for reduction of plasma cholesterol levels, particularly in patients with heterozygous familial hypercholesterolemia. This procedure is also applicable to treatment of sitosterolemia, a rare genetic disorder in which the absorption of plant sterols is abnormally high. Although no major complications of this method have been reported, more extensive studies are required to evaluate its long-term effects on renal and hepatic function. Similarly, long-term impact of this procedure on progression/regression of atherosclerotic lesions must be documented. Finally, indications for this procedure should be carefully considered, particularly in view of availability of other treatments of dyslipidemia.

Animals↗
PubMedDate not supplied

A comparison of colour duplex ultrasonography after transurethral alprostadil and intracavernous alprostadil in the assessment of erectile dysfunction.

This study aimed to investigate whether transurethral alprostadil could be used for the diagnosis of erectile dysfunction using colour duplex ultrasound. The ultrasonography results were compared after transurethral and intracavernous alprostadil administration in 20 patients with erectile dysfunction. There were no significant differences in the mean peak systolic velocities (PSVs) between the two routes of administration, but the mean end diastolic velocities (EDVs) showed significant differences, with patients treated with transurethral alprostadil having higher EDVs. Linear regression analysis of the PSVs reached following the two routes of administration showed a moderate relationship, but linear regression analysis of the EDVs showed no relationship. We concluded that transurethral alprostadil was an inappropriate vasoactive drug to use with colour duplex ultrasonography for the evaluation of patients with erectile dysfunction because it required a longer scan time and it was less effective and less reliable than intracavernous alprostadil at stimulating complete corporeal smooth muscle relaxation.

Adult↗
PubMedDate not supplied

Comparing risk-adjusted hospital mortality for CABG and AMI patients.

The objectives of this study were to compare the risk-adjusted mortality of coronary artery bypass graft (CABG) and acute myocardial infarction (AMI) patients simultaneously in six hospitals in Seoul, Korea, and to investigate the relationship between these performance measures by developing a predictive model of mortality. The medical records of 749 AMI and 564 CABG patients were reviewed. A predictive model was developed using logistic regression, including 170 variables selected as risk factors for risk adjustment. The validity of our predictive model was demonstrated to be within an acceptable range. The results showed that one hospital with a significantly low AMI mortality rate also had a low CABG mortality rate, while another hospital with a significantly high AMI mortality rate also had a high CABG mortality rate. Our results implied that hospitals providing good-quality medical management of coronary artery disease also provided a good-quality surgical service.

Adult↗