Association between excessive Internet use and oral health behaviors of Korean adolescents: A 2015 national survey.

OBJECTIVE: This study aimed to investigate excessive Internet use's (EIU's) association with oral health behaviors among Korean adolescents. BASIC RESEARCH DESIGN: This cross-sectional study was based on the 11th Korea Youth Risk Behavior Web-based Survey (2015). PARTICIPANTS: 68,043 school students aged 13-18 years (35,204 boys and 32,839 girls). Data on, 45,271 (23,354 males and 21,917 females using the Internet on weekdays) and 49,324 (27,448 males and 21,876 females using the Internet on weekends) were analyzed after excluding questionnaires with missing values. MAIN OUTCOME MEASURES: The key variables were oral health behaviors (tooth-brushing frequency and tooth brushing after lunch at school, and preventive oral health behaviors), EIU (hours of Internet use on weekdays and weekends, excluding use for academic purposes). RESULTS: Compared to the general groups, the odds ratio (OR) for less tooth-brushing was 4.04 (95%CI=2.990-5.459) and 3.55-fold higher (95% CI=2.703-4.659) in the high-risk groups for weekday and weekend EIU, respectively. For post-lunch tooth-brushing, compared to the general groups, the OR for less tooth-brushing was 1.7-fold higher in the high-risk groups for EIU during weekdays and weekends. The OR for no preventive behavior was significantly higher in the high-risk groups than in the potential-risk and general groups. CONCLUSIONS: Policies moderating adolescents' EIU may enable appropriate oral health behaviors.

Mandibular stability using sliding or conventional four-hole plates for fixation after bilateral sagittal split ramus osteotomy for mandibular setback.

Our aim was to compare the postoperative stability of the mandible when two different fixation methods had been used after bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. The study included 23 patients who had two-jaw BSSRO mandibular setback at the Department of Oromaxillofacial Surgery, Korea University Guro Hospital, between January 2011 and June 2014. The first group (four-hole (control) group, n=13) comprised patients whose bony segments were fixed with conventional four-hole plates, and the second (sliding plate (experimental) group, n=10) included patients whose bone segments were fixed with sliding plates. Lateral cephalograms were taken and analysed at three time points: preoperatively (T1), and one week (T2), and 1year (T3) postoperatively. The Mann-Whitney U test was used to compare the postoperative stability of the mandible in each group. There were no significant differences between the two groups in changes in the horizontal and vertical positions of point B and pogonion postoperatively, nor were there any significant differences between them in ramal inclination and inclination of the SN plane with point B at the given time points (p=>0.05 in surgical changes in the mandible immediately after surgery and 0.397, 0.616, 0.082, 0.951, 0.901, 0.476 in postoperative changes in the mandible 1 week to 1 year after surgery). Like the conventional four-hole plate, the sliding plate can also be used to achieve stability in the fixation of mandibular bone segments after BSSRO.

Enhanced fibrin remodeling in vitro with TGF-beta1, insulin and plasmin for improved tissue-equivalents.

The aim of this study was to better understand how to increase collagen content in and enhance mechanical properties of tissue-equivalents formed by entrapping tissue cells in fibrin gels, with the ultimate goal of developing mechanically robust artificial tissues. The two main areas of focus were cell culture medium composition and replacement frequency relative to a base case of incubating constructs in medium supplemented with just serum and replaced weekly. The optimal condition involved a combination of all three factors investigated-TGF-beta, insulin, plasmin-with medium replacement three times a week. Compared to a base case without these three factors, the combination case resulted in 20 times more collagen and a ten-fold increase in tensile strength. The high strain modulus and tensile strength were within an order of magnitude of cardiovascular tissues. This study indicates great potential for fibrin-based tissue-equivalents in soft connective tissue applications.

Establishment of an animal embryo culture system containing various embryotropins and its efficacy for culturing ICR mouse one-cell embryos derived in vivo or in vitro.

OBJECTIVE: To develop an effective ICR mouse embryo culture medium. DESIGN: In vitro model study. SETTING: University-affiliated hospital. ANIMALS: Four-week-old, superovulated mice. INTERVENTION(S): In vivo- or in vitro-derived one-cell embryos were cultured in preimplantation-1 medium (P-1). MAIN OUTCOME MEASURE(S): Preimplantation development. RESULT(S): In vivo-derived embryos were cultured in BSA-containing P-1, to which one of the following substances was added: [1] no addition, [2] amino acids (aa), [3] aa+hemoglobin (hb), [4] aa+hb+cysteine (cys), [5] aa+hb and glucose (glu) added at the four-cell, or [6] aa+hb and glu+cys added at the four-cell stage. More (P<0.05) blastocysts developed after aa or aa+hb addition than after no addition, and glu addition to such medium further stimulated the formation (54%). In P-1 with aa+glu, the addition of 1 microg/mL hb was optimal. Additional improvement of blastocyst formation (78%) was achieved by ethylenediaminetetraacetic acid (EDTA), supplementation and bovine serum albumin replacement with polyvinyl alcohol (PVA) did not inhibit the development. P-1 supplemented with aa, hb, glu, EDTA, and PVA also supported the development of in vitro-derived embryos (70%). CONCLUSION(S): A modified P-1 medium was developed, and it supported the development of both in vivo- and in vitro-derived ICR mouse embryos.

Polymerase chain reaction reveals herpes simplex virus DNA in saliva of patients with Behçet's disease.

The etiology of Behçet's disease is unclear, but viral infection is thought to be one etiologic factor. The aims of this study were to detect herpes simplex virus (HSV) DNA in the saliva of patients with Behçet's disease and of healthy persons, to determine whether the presence of HSV in saliva is associated with the presence of intraoral ulcer, and to investigate the relationship between HSV and Behçet's disease. The polymerase chain reaction (PCR) was used to detect HSV DNA sequences in DNA extracted from the saliva of patients with Behçet's disease and of healthy control subjects. Of 66 patients with Behçet's disease diagnosed clinically, 19 were diagnosed as complete type, 29 as incomplete type and 18 as suspected type. Of 66 DNA preparations from the saliva of the patients, 26 (39.4%) showed the 289-bp band. This contrasts with 12 of 87 preparations (13.8%) from healthy controls (P < 0.01). There were no significant differences among the three patient groups. All the 289-bp bands analyzed by restriction endonuclease digestion yielded the expected 158-bp and 131-bp fragments when digested with PstI.HSV DNA was detected in 12 of 33 Behçet's disease patients (36.4%) with oral ulceration and 14 of 33 patients (42.4%) without oral ulceration at the time of testing. There was no statistically significant correlation in the PCR results between the two groups.

Effect of phthalate plasticizer on blood compatibility of polyvinyl chloride.

The amount of a phthalate plasticizer on the surface of a sheet of polyvinyl chloride used in the fabrication of blood storage bags was quantified using attenuated total reflectance spectroscopy, water contact angle measurement, and weight loss due to methanol extraction. Water wettability increased as the amount of surface phthalate extracted by methanol increased, which indicates that the accumulation of phthalate on the surface increases hydrophobicity. The extraction of phthalate by methanol consists of two steps: (a) methanol first dissolves surface phthalate, and (b) phthalate in the bulk then diffuses through the surface. The adsorption of plasma proteins was investigated to determine the initial events as blood contacts the surface. The composition of adsorbed proteins on the methanol-cleansed surface differs from that on the uncleansed polyvinyl chloride surface. Albumin adsorption onto phthalate-contaminated surfaces is less than on cleansed surfaces while adsorption of gamma-globulin and fibrinogen is greater on phthalate-contaminated surfaces. Protein adsorption can be related to surface thrombus formation. Increases in platelet numbers appeared on phthalate-contaminated surfaces as compared with methanol-treated surfaces. A phthalate may enhance platelet adhesion and aggregation when it exists on a polymer surface.

A new mineral trioxide aggregate root-end filling technique.

Carrier and syringe-type devices are currently used to deliver mineral trioxide aggregate as a root-end filling material. In certain surgical situations these devices may be too difficult to use because of the location of the surgical site and the small size of the root-end preparation. This paper describes a new technique to overcome these difficulties by the formation and delivery of mineral trioxide aggregate pellets.

In vitro maturation of porcine oocytes using a defined medium and developmental capacity after intracytoplasmic sperm injection.

To establish a defined in vitro maturation culture system for porcine oocytes, we examined the effects of adding cysteine (Cys) and epidermal growth factor (EGF) to the maturation medium. Furthermore, to evaluate cytoplasmic maturation, we investigated GSH concentrations and embryo development after intracytoplasmic sperm injection (ICSI). The basic media for IVM were modified TCM199 containing 10% newborn calf serum (NBCS) or 0.1% polyvinyl alcohol (PVA), supplemented with amino acids. Adding EGF (10 ng/ml) or EGF + Cys (0.57 mM) to the defined medium (0.1% PVA + amino acids) increased (P < 0.05) the rate of nuclear maturation relative to the defined medium (without these additives). After ICSI, oocytes matured in a medium supplemented with NBCS, Cys and EGF had a higher (P < 0.05) rate of pronuclear formation rate than oocytes matured in the defined IVM medium. Although there was no significant difference in cleavage rates between NBCS- and PVA-containing media supplemented with both Cys and EGF, the rate of blastocyst development was lower (P < 0.05) in the defined medium than in the NBCS-containing medium. Intracellular GSH concentrations of oocytes matured in the NBCS- and PVA-containing media supplemented with both Cys and EGF were higher (P < 0.05) than in oocytes matured in PVA alone or in oocytes before maturation. Adding Cys and EGF to a defined medium for porcine IVM improved rates of nuclear maturation and cleaved oocytes following ICSI, probably due to increased GSH concentrations. Also, embryos derived from oocytes matured in the defined medium (with the addition of Cys and EGF) developed into blastocysts after ICSI.

Effects of amino acids on maturation, fertilization and embryo development of pig follicular oocytes in two IVM media.

This study was conducted to develop a serum-free, defined medium for IVM of pig oocytes. Modified North Carolina State University (mNCSU)-23 media with or without supplementation with both epidermal growth factor (EGF) and gonadotrophin were used as base media. In separate experiments, each base medium was supplemented with porcine follicular fluid (pFF), polyvinyl alcohol (PVA), PVA and essential amino acids (EAA), PVA and nonessential amino acids (NEAA) or PVA with both EAA and NEAA. Averaged across these five treatments, the percentage of blastocyst formation was higher (P < 0.05) in the base medium supplemented with EGF and gonadotrophins. In both base media, the addition of NEAA yielded similar percentages of maturation (81-82% versus 75-80%), sperm penetration (89-93% versus 80-86%) and blastocyst formation (4-18% versus 4-13%) as media supplemented with pFF. Although similar benefits were found after the addition of EAA, their addition was associated with lower (P < 0.05) maturation (66%) and sperm penetration (58%) than when pFF was added to the base medium without EGF and gonadotrophins. However, decreased maturation after EAA addition was not detected in the base medium containing EGF and gonadotrophins. Within the same base medium, monospermy, male pronucleus formation, cleavage and blastocyst formation were not affected by the treatments; and combined addition of EAA and NEAA did not further improve oocyte development. In conclusion, a maturation system using a defined mNCSU-23 medium supplemented with EGF, gonadotrophins and EAA or NEAA was developed which yielded a similar number of blastocysts compared with a pFF-containing medium.

Correlation of antibiotic prophylaxis and difficulty of extraction with postoperative inflammatory complications in the lower third molar surgery.

Our aim was to investigate the correlation among antibiotic prophylaxis, difficulty of extraction, and postoperative complications in the removal of lower 3rd molars. A total of 1222 such extractions in 890 patients between January 2010 and January 2012 were analysed retrospectively. The difficulty of extraction measured by Pederson's index, antibiotic prophylaxis with cefditoren, and postoperative complications were recorded. The difficulty of extraction was significantly associated with postoperative complications (p=0.03). There were no significant associations between antibiotic prophylaxis and postoperative complications in groups of equal difficulty ("easy" group (class I) p=1.00; "moderate" group (class II) p=1.00; and "difficult" group (class III) p=0.65). There was a small but insignificant increase in the number of dry sockets and infections in class III cases. In conclusion, this study provides further evidence that antibiotic prophylaxis for the prevention of postoperative inflammatory complications is unnecessary for extraction of 3rd molars.

Epidemiological characteristics of the 2002 outbreak of foot-and-mouth disease in the Republic of Korea.

The Republic of Korea experienced a foot-and-mouth disease (FMD) outbreak during May-June 2002. The present study describes epidemiological characteristics of the 2002 FMD outbreak in Korea, including the pattern of the outbreak in both time and space, transmission routes among infected farms, and control measures. One of the notable features of the 2002 FMD epidemic in Korea was that the virus infected mostly pigs [15 of 16 infected premises (IPs)], despite the presence of other susceptible animals on infected and neighbouring farms. The epidemic showed temporal clustering at 8-9 day intervals, suggesting five generations of infection during the outbreak, and 13 of 16 (81.3%) IPs were located within a 10 km-radius of the index case. The clinical signs that prompted notification of infection included vesicles around hooves and snouts. The age of lesions was significantly less among cases reported by farmers compared with veterinarians. The high awareness of farmers from an earlier FMD outbreak greatly helped the animal hygiene authority in efforts associated with disease control and eradication. The outbreak was eradicated within <2 months as a result of the intensive control efforts of the animal hygiene authorities and the cooperation of the Korean people. Although the outbreak was a costly lesson for the Korean people, the experience gained will contribute to future efforts in the prevention and control of animal infectious diseases.

Medical care use by Mexican-Americans: evidence from the human population laboratory studies.

Data are presented from sample surveys conducted in 1974 (N = 3,119) and 1975 (N = 657) in Alameda County, California, by the Human Population Laboratory. Mexican-Americans are compared to Anglos and blacks in terms of physician visits, dental examinations, general physical examinations, and eye examinations. Comparison of crude percentages indicates that there is very little ethnic variation in either sample regarding regular source of medical care or health insurance coverage, although the trend is for fewer Chicanos to have such coverage. In terms of physician visits, there is little difference between Anglos and Chicanos. By contrast, fewer Chicanos and blacks report dental examinations in the past year (Chicanos have the lowest rate). Fewer Chicanos report a general medical examination in the past year and more report never having had a medical checkup. Likewise, more Chicanos report never having an eye examination while relatively fewer report such an exam in the past year. Controlling for the effects of age, sex, education, family income, health insurance, regular source of care, physical health status and perceived health reduces differences in rate of physician visits among the ethnic groups, primarily by reducing the rate for blacks and increasing the rate for Chicanos. Likewise, adjustment for all 8 factors reduces ethnic differences in general medical examination rates, in this case by increasing the rates for the minority groups. Adjustment reduces the ethnic differences in dental examination rates by increasing the minority group rates, but large differences still remain. For eye examinations, adjustment has little effect on the rates for Anglos and blacks, but substantially increases the rate for Chicanos. For all 4 types of medical care behavior, controlling for the effects of education and family income (so-called inequitable reasons for lower access to care) consistently produces the greatest effect, particularly for Chicanos. In each case, the effect is to create greater parity between Chicanos and Anglos by increasing the utilization rate for Chicanos. However, even after adjustment, the rate for Chicanos remains lower.

The antiplatelet activity of immobilized prostacyclin.

Owing to the chemical instability of prostacyclin, the direct immobilization of this prostaglandin has not been successful. A new procedure is described for the preparation of immobilized prostacyclin based on the conversion of immobilized prostaglandin F2 alpha to immobilized prostaglandin I2-Materials thus prepared show dramatic antiplatelet effects with regard to platelet aggregation and platelet adhesion. Radioimmunoassays of plasmas used in in vitro platelet tests and of buffers used in prostacyclin leakage studies established that these effects are not due to the release of prostacyclin from the respective immobilization substrates.

Health characteristics by longest held occupation and industry of employment: United States, 1980.

Occupational and industrial hazards are unevenly distributed in the workplace. National estimates for selected health indices of persons aged 17 years and over in the civilian noninstitutionalized population are presented for categories of longest held occupation and industry of employment. These estimates were based on data collected by the National Center for Health Statistics (NCHS) in the 1980 National Health Interview Survey (NHIS) and the Occupational Supplement, the first survey to collect data on longest held, in addition to current, occupation and industry of employment. Data on length of longest held job, limitation of activity, disability days, incidence of acute conditions, persons injured, hospitalizations, and utilization of medical and dental services are presented.

Supplemental oxygen controls cellular proliferation and anastomotic intimal hyperplasia at a vascular graft-to-artery anastomosis in the rabbit.

PURPOSE: The purpose of this study was to determine whether the administration of 40% supplemental oxygen (O ( 2) ) will decrease cellular proliferation and intimal hyperplasia (IH) at a prosthetic vascular graft (PVG)-to-artery anastomosis. METHODS: Twenty New Zealand white rabbits underwent placement of a 3-mm polytetrafluoroethylene graft in their infrarenal aorta. Four groups of five rabbits were placed either in a normoxic (21%) environment or in a 40% supplemental O ( 2) environment for 7 or 42 days. Twenty-four hours before the rabbits were humanely killed for aortic graft harvest, BrDU (5-bromo-2'-deoxyuridine) was injected into the rabbits intraperitoneally. Image analysis (Bioquant) morphometrics were used to measure cells with BrDU staining and intimal areas at the distal anastomosis. Cellular proliferation is defined as positively staining BrDU cells divided by all cells in the artery wall. IH is reported as a ratio between the intimal area and the medial area to standardize the varying aortic size and degree of aortic fixation among rabbits. The Student t test was used to compare cellular proliferation and IH between control and O ( 2) -treated rabbits. RESULTS: Cellular proliferation in the intima at 7 days was significantly reduced in the O ( 2) -treated animals (1.7% +/- 1%) versus the control animals (28.6% +/- 3%) ( P =.0001). The cellular proliferation in the intima at 42 days returned to preoperative levels in the O ( 2) -treated group (0.15%) and in the control group (0.11%) ( P = not significant). IH at 7 days was minimal, and no difference between the O ( 2) -treated group (0.017 +/-.006) and the control group (0.009 +/-.03) ( P = not significant) was found. IH was significantly reduced at 42 days in the O ( 2) -treated animals (0.031 +/-.012) when compared with the control animals (0.193 +/-.043) ( P =.006). CONCLUSIONS: Supplemental O ( 2) (40%) significantly reduces cellular proliferation and IH at the distal anastomosis of a PVG-to-artery anastomosis in the rabbit model.

Association of artery wall hypoxia and cellular proliferation at a vascular anastomosis.

BACKGROUND: We hypothesize that arterial wall hypoxia incites the pathologic formation of intimal hyperplasia at an artery anastomosis. We have determined from previous studies performed in our laboratory, the oxygen tension profiles of the artery wall at various times after vascular anastomosis. The purpose of this study is to determine the rate of cellular proliferation at an artery anastomosis when the artery wall is most hypoxic. MATERIALS AND METHODS: Expanded polytetrafluoroethylene (ePTFE) grafts were placed end to end in the infrarenal aorta of 27 New Zealand white rabbits. The anastomotic aortic wall oxygen (O(2)) tensions were measured with an O(2) microelectrode in rabbits 0, 7, 14, 28, and 42 days after surgery. O(2) tensions were also measured in 4 control rabbits for comparison. 5-Bromo-2'-deoxyuridine (BrDU) was injected intraperitoneally 24 h prior to rabbit sacrifice. After O(2) tension measurements, the rabbits were sacrificed and the aortic grafts were harvested. Bioquant morphometrics was used to measure cells with BrDU counterstaining and intimal thickness in 17 rabbits: in control (n = 4), Day 0 (n = 4), 7 (n = 5), and 42 (n = 4). Student's t test was used to compare O(2) tensions, cellular proliferation, and intimal hyperplasia between days. RESULTS: The pO(2) levels at the outer layers of the aorta, 1 mm distal to the distal aortic graft anastomosis, were 61.0 +/- 2 (+/-SE) mm Hg for controls, 19.8 +/- 1 mm Hg for Day 7 (P < 0.0001), 19.0 +/- 1 mm Hg for Day 14, 39.2 +/- 1 mm Hg for Day 28, and 58.5 +/- 1 mm Hg for Day 42 aortic grafts. BrDU-staining ratios in the intima were significantly higher in the Day 7 aortic grafts, 28.6 +/- 3%, versus BrDU-staining ratio, 1.4 +/- 1%, in Day 42 aortic grafts (P < 0.0002). CONCLUSIONS: Cellular proliferation is highest at Day 7 when the artery wall is most hypoxic and returns to baseline as O(2) tensions normalize.

Role of protein and fatty acid adsorption on platelet adhesion and aggregation at the blood-polymer interface.

Thrombus formation on a foreign surface is a complicated process, involving many factors. However, there is little doubt that a foreign surface adsorbs plasma proteins upon blood contact and that the nature of this adsorbed layer may determine the mechanism of platelet adhesion and aggregation. The adhesion and aggregation of platelets play an important role in the initial events of thrombus formation on a foreign surface. In this work, adsorption studies using human blood plasma were done on several polymer surfaces. Some drugs which prevent platelet adhesion were utilized to verify the proposed mechanism for platelet adhesion which includes glycosyl transferase reaction. Also, adsorption and release of fatty acid salts, including fatty acid-bonded albumin, were investigated at different polymer interfaces. It is postulated that adsorbed fatty acid salts are released from the surface upon contact with plasma to form a high local concentration of fatty acid, and that this fatty acid suspension would cause platelet aggregation at the interface.

Experimental studies on the antiviral agent famciclovir in Behçet's disease symptoms in ICR mice.

BACKGROUND: Chronic oral aphthae, recurrent genital ulcers and uveitis are the three main manifestations of Behçet's disease (BD). The aetiopathogenesis of BD is still obscure, but herpes simplex virus (HSV) is one of the possible causal factors. Various kinds of drugs, including immunosuppressants and aciclovir have been used in treatment, but effectiveness is variable. OBJECTIVES: To demonstrate the efficacy of famciclovir, an antiviral compound that acts against HSV, varicella-zoster virus and hepatitis B virus, in a murine model of BD. METHODS: Using the HSV-induced BD mouse model, famciclovir was administered variously before and after inoculation or from the day of lesion occurrence, with appropriate controls. Ulceration of the mouth and genital skin and eye involvement were monitored. In addition, spleen cytokine expression was measured by polymerase chain reaction. RESULTS: Pretreatment and concurrent treatment did not affect the occurrence of BD, but treatment from the appearance of lesions was effective in improving BD and preventing recurrence. After famciclovir, interleukin 2 expression correlated with the recurrence of BD symptoms. CONCLUSIONS: This model suggests the possible role of immune response to viral infection in the development and activation of BD. The study provides a rationale for clinical trials of famciclovir in the human form of BD.

Expression of Th2 cytokines decreases the development of and improves Behçet's disease-like symptoms induced by herpes simplex virus in mice.

In the etiology of Behçet's disease (BD), viral infection has long been postulated as a contributing factor, and viral involvement has been demonstrated. However, viral infection alone is not sufficient to explain the pathogenesis of BD, and some evidence suggests that immunologic abnormalities are also important. To study the possible role of immune regulation in the development of BD-like symptoms induced by herpes simplex virus inoculation in ICR mice, macrophages were deleted by use of liposome-encapsulated clodronate (lip-Cl(2)MDP). Treatment with lip-Cl(2)MDP suppressed the development of BD-like symptoms, and this suppression was correlated with the induction of interleukin-4 expression in mouse spleens. When the Th2 adjuvant ovalbumin (OVA)-alum was injected into mice with BD-like symptoms, their cutaneous symptoms improved. Adoptive transfer with splenocytes from OVA-alum-injected mice also resulted in improvement. These findings suggest that up-regulated Th2 cytokine expression can attenuate the development of and improve some BD-like symptoms.