Molecular damage and responses of oral keratinocyte to hydrogen peroxide.

BACKGROUND: Hydrogen peroxide (H2O2)-based tooth bleaching reagents have recently increased in popularity and controversy. H2O2 gel (3%) is used in a Nightguard for vital bleaching; transient tooth sensitivity and oral mucosa irritation have been reported. Genotoxicity and carcinogenicity have also been significant concerns. METHODS: We used primary cultured normal human oral keratinocytes (NHOKs) as an in vitro model to investigate the pathological effects to mitochondria functions on human oral keratinocytes exposed to different doses of H2O2 for different durations. RESULTS: An MTT assay showed compromised cell viability at a dose over 5 mM. The treatments induced nuclear DNA damage, measured using a single-cell gel electrophoresis assay. A real-time quantitative polymerase chain reaction showed H2O2 induced significant increase in mitochondrial 4977-bp deletion. Mitochondrial membrane potential and apoptosis assays suggested that oxidative damage defense mechanisms were activated after prolonged exposure to H2O2. Reduced intracellular glutathione was an effective defense against oxidative damage from 5 mM of H2O2. CONCLUSION: Our study suggests the importance for keratinocyte damage of the dose and the duration of the exposure to H2O2 in at-home-bleaching. A treatment dose ≥100 mM directly causes severe cytotoxicity with as little as 15 min of exposure.

Severe bronchopulmonary dysplasia is associated with higher fluid intake in very low-birth-weight infants: a retrospective study.

OBJECTIVE: This study aims to investigate the association between fluid intake in the first 4 days of life and the subsequent severity of bronchopulmonary dysplasia (BPD) in very low-birth-weight infants (VLBWI). STUDY DESIGN: A retrospective chart review of 75 infants with a gestational age of less than 32 weeks and a birth weight of < 1,500 g was performed. Demographic, clinical data, associated maternal risk factors, and amount of fluid received in the first 4 days of life were analyzed. RESULTS: Severe BPD was associated with a lower gestational age (27.04 ± 2.073 wks vs. 28.70 ± 1.706 wks, p=0.001), lower birth weight (981.44 ± 244.54 vs. 1,199.63 ± 165.39 g, p < 0.001), use of surfactant (91.7 vs. 63%, p=0.002), patent ductus arteriousus (PDA) (70.8 vs. 37%, p=0.004), pulmonary hemorrhage (14.6 vs. 0%, p=0.045), and more fluids received from the 2nd to 4th days of life (346.44 ± 42.38 mL/kg vs. 323.91 ± 27.62 mL/kg, p=0.007). A cut off point of 345 mL/kg of fluids from the 2nd to 4th days of life was selected using receiver operating characteristic curve analysis, and remained a significant risk factor even after multiple logistic regression analysis. CONCLUSION: Our findings demonstrate that VLBWI who received higher fluid intake from the 2nd to 4th days of life are at an increased risk of developing severe BPD.

Comparison of neonatal outcome for inborn and outborn very low-birthweight preterm infants.

BACKGROUND: The aim of the present study was to compare the neonatal outcome of very low-birthweight (VLBW) preterm infants with regard to inborn and outborn status in a medical center of Southern Taiwan, where short-distance neonatal transport is the rule and maternal transport was not well established. METHODS: This retrospective study included outborn VLBW preterm infants admitted to the neonatal intensive care unit of Chang Gung Memorial Hospital at Kaohsiung after neonatal transport during the period from 1999 through 2003. An equal number of inborn preterm infants matched for gender and birthweight were included as controls. Infants with lethal congenital anomalies or who died in the delivery room were excluded. Data were collected from reviewing medical charts. RESULTS: A total of 34 inborn VLBW infants and 34 outborn VLBW infants with neonatal transport were included. Chronic lung disease (CLD) was significantly more frequent in the outborn group according to McNemar test (P = 0.0124) and logistic regression. Logistic regression also showed that outborn status (P = 0.0173) and birthweight (P = 0.0024) were the two most important risk factors for development of CLD. CONCLUSION: Well-trained short distance neonatal transport is useful and valuable for VLBW infants with gestation age of 27-34 weeks in Southern Taiwan. The respiratory outcome, however, was poor in the outborn group in terms of incidence of CLD. To improve the respiratory outcome, further modification of respiratory care during transportation or antenatal maternal transport is crucial.

Tissue expression of gelsolin in oral carcinogenesis progression and its clinicopathological implications.

Gelsolin has important cellular functions, including cell motility, proliferation and apoptosis. Altered gelsolin expression has been reported in several types of human malignancies, but has not been evaluated in oral carcinogenesis. In this study, all normal oral mucosa (n=12) had high gelsolin expression, whereas only 7.7% of oral precancerous lesions (n=26) had positive gelsolin expression. A significant increased positive staining was found in primary (n=51; 37.3%) and metastatic (n=26; 30.8%) oral squamous cell carcinoma lesions. Tumors with high gelsolin expression were associated with greater tumour size (P=0.007), invasive growth (P=0.02), and younger age (P=0.006). High gelsolin expression conferred a poor clinical outcome in patients with metastatic disease (P=0.005). In conclusion, a biphasic profile in gelsolin expression was observed during the progression of oral carcinogenesis. This may be due to a balance of its multiple cellular functions in tumour invasion and cell growth. The underlying mechanisms, however, remain to be elucidated.

Bond strength and debonding characteristics of a new ceramic bracket.

INTRODUCTION: The purposes of this study were to evaluate the shear bond strength of a new collapsible monocrystalline bracket (Inspire, Ormco, Orange, Calif) and compare it with another collapsible ceramic bracket (Clarity, 3M Unitek, Monrovia, Calif) and a metal bracket; to examine the modes of failure after shear bond strength testing; and to observe the tooth surface after debonding the ceramic brackets with pliers. METHODS: One hundred extracted human premolars were selected for bonding. Three types of brackets and 2 orthodontic adhesives (Transbond XT, 3M Unitek; and Enlight, Ormco) were used. After bonding, all samples were placed in a distilled water bath at 37 degrees C for 24 hours. The shear bond strength of 60 samples was measured, and the remaining 40 samples with ceramic brackets were debonded with pliers. RESULTS: No statistically significant differences in bond strengths among the different combinations of brackets and adhesives were found (P > .05). The mode of failure after debonding by either shear bond strength testing or with pliers was predominantly at the bracket/adhesive interface in all groups. Enamel and bracket fractures were noted in 2 and 5 of 20 samples for Inspire, and 1 and 0 of 20 samples for Clarity after debonding with pliers. CONCLUSIONS: Bond strength and mode of failure of Inspire were similar to those of Clarity, but the risk of bracket fracture after debonding for Inspire was greater.

Risk factors for hemodynamically-unrelated cystic periventricular leukomalacia in very low birth weight premature infants.

BACKGROUND AND PURPOSE: Periventricular leukomalacia (PVL) is one of the most important complications of prematurity, but its cause remains unclear. This study investigated the risk factors for hemodynamically-unrelated cystic PVL in very low birth weight (VLBW) premature infants. METHODS: VLBW premature infants admitted to the neonatal intensive care unit from 1998 through 2002 were included in this retrospective study. Infants who had congenital lethal anomalies or who died before a cranial scan could be done were excluded. All VLBW infants received serial cranial ultrasound examinations to screen for cystic PVL during hospitalization. Infants with cystic PVL were divided into those with or without a hemodynamic event of sufficient severity to potentially cause cystic PVL. The charts of all included infants were reviewed and relevant clinical parameters were analyzed. RESULTS: Cystic PVL occurred in 20 VLBW infants (6.9%) during the study period. Four of these infants (20%) had hemodynamic events before the development of cystic PVL and 16 (80%) had hemodynamically-unrelated cystic PVL. Univariate analysis showed that infants with hemodynamically-unrelated cystic PVL were more likely to have symptomatic patent ductus arteriosus (PDA) [p < 0.01] and bronchopulmonary dysplasia (BPD) [p < 0.01]. However, logistic regression indicated VLBW premature infants with BPD combined with symptomatic PDA (odds ratio, 8.92; 95% confidence interval, 2.55-31.20; p < 0.01) were at greatest risk for development of hemodynamically-unrelated cystic PVL. CONCLUSION: BPD and symptomatic PDA were more common in infants with hemodynamically-unrelated cystic PVL, although the reasons for these associations were unclear. Serial cranial scans are strongly suggested for VLBW premature infants with BPD and symptomatic PDA to screen for the development of cystic PVL.

Oral precancerous disorders associated with areca quid chewing, smoking, and alcohol drinking in southern Taiwan.

OBJECTIVE: To investigate the prevalence and the associated risk factors of oral precancerous disorders in southern Taiwan. METHODS: We conducted a cross-sectional community survey interviewing 1075 adult subjects, 15 years of age and over, gathered from randomly selected 591 households, and spanning five villages in southern Taiwan. The study protocol included a visual oral soft tissue examination and a questionnaire-based interview. The chi-square test was used to test the differences in prevalence of oral precancerous lesions and conditions by different "life styles" relating to current risk habits of current areca quid chewing, smoking, and alcohol drinking. To control for possible confounding, a logistic regression model was used to estimate the Odds Ratios (OR) for leukoplakia and oral submucous fibrosis (OSF). RESULTS: 136 precancerous lesions and conditions were detected among 1075 subjects (12.7%). The analysis of the spectrum of oral precancerous disorders detected, leukoplakia (n = 80), OSF (n = 17) and verrucous lesions (n = 9), demonstrated an association with gender (P < 0.001). There were statistically significant associations among leukoplakia (P < 0.01), OSF (P < 0.0001), and verrucous lesions (P < 0.0001) and the life style of current areca quid chewing, smoking, and alcohol drinking. The synergistic effect of smoking and areca quid chewing habit on leukoplakia and OSF was demonstrated. CONCLUSION: This study reinforces the association of current areca quid chewing without tobacco, cigarette smoking, and alcohol drinking to leukoplakia, OSF, and verrucous lesions in Taiwan.

Comparison of 2 methods of making surgical models for correction of facial asymmetry.

PURPOSE: Stereolithography is useful in reconstructive surgery in that the surgical template or customized implant can be prefabricated on the models. To correct facial asymmetry, prior reshaping of the replica of the original structures is frequently required before it can be used as a surgical model. This is traditionally accomplished by direct sculpturing. This method has its limitations in clinical use. Recently, we developed a method using computer techniques to reconstruct the required structures. We herein report several of its applications in a variety of clinical situations and compare this virtual method with the traditional method. PATIENTS AND METHODS: With the traditional method, reconstruction of the models was handmade on the replica of the original structures. In the virtual method, the anticipated reconstructions were completed on the computer using various image-processing tools and were verified by the surgeons before sending to stereolithography. Thirteen patients who had undergone surgical correction of facial asymmetry using models made by either method were retrospectively reviewed. The traditional method was used in 5 of them while the virtual method was applied in the other 8 patients. The surgical models and the patients following the reconstruction were evaluated for symmetry and esthetics. RESULTS: To construct implants or to precontour fixation plates, an average of 1.4 models was fabricated for each patient using the traditional method, whereas only 1.1 models were made for each patient in the virtual method group. Both methods worked satisfactorily in restoring symmetry of the bony structures on the models. However, the projection of the chin on the model created by the traditional method was inadequate, as showed postoperatively in 1 patient. There was surface roughness on the customized area of the models made by the virtual method. The surgical result was poor in symmetry in 1 case in the traditional method group. One patient in the virtual method group showed irregularities on the temporal region following augmentation with prefabricated bone cement implant. CONCLUSIONS: Both methods of making models were useful and effective in surgical reconstruction for facial symmetry in selected cases. The virtual method was preferred in cases where midline structures had already been deformed, or when soft tissue was involved in reconstruction. From the technical standpoint, the virtual method was superior because of its versatility, predictability, precision, communicability, and the convenience of storage and documentation.

Risk factors of retinopathy of prematurity in premature infants weighing less than 1600 g.

There are many risk factors contributing to retinopathy of prematurity (ROP). Some are still controversial, including the use of glucocorticoid and intraventricular hemorrhage. Hence, a retrospective study was performed to evaluate the association between the suspected risk factors and ROP in a medical center in southern Taiwan. One hundred fifty-nine infants with birth body weight < 1600 g admitted to our neonatal intensive care unit before the 29th day of life were enrolled into this study. Clinical data were analyzed by means of logistic regression. The prevalence of ROP in all infants (birthweight < 1600 g) is 36.48% (58 of 159) and 59.46% (22 of 37) in extremely low birthweight infants (birthweight < or = 1000 g). One infant with gestational age 32 weeks and birthweight 1420 g developed stage III ROP. Logistic regression revealed six factors to be significant variables. Birthweight < or = 1000 g, intraventricular hemorrhage, sepsis, and use of glucocorticoid or dopamine were risk factors associated with higher incidence of ROP. Supplementation of vitamin E was shown to relate to lower incidence of ROP. This study confirms several risk factors recognized in previous statistical analyses. Sepsis is the most significant factor contributing to ROP. Vitamin E was proven to be effective in prophylaxis of development of ROP. The possibility of development of ROP could not be excluded in infants with gestational age > 32 weeks.

Neonatal group B streptococcal infection: a 7-year experience.

BACKGROUND: This retrospective study was designed to determine the trend of neonatal group B streptococcal (GBS) infection during the past 7 years at the Chang Gung Memorial Hospital of Kaohsiung, as well as to assess the risk factors, clinical features and patient outcomes. METHODS: Medical records of infants with neonatal GBS infection identified by positive results of cultures of sterile body fluid in our hospital from January 1996 through December 2002 were reviewed for demographic and clinical data. RESULTS: There were 33 infants with neonatal GBS infections during the past 7 years in our hospital. The number of patients increased from 1996 to 2001. Sixteen infants had early onset infections and 17 infants had late onset infections. Of the nine patients with maternal risk factors in the early onset group, prolonged rupture of membranes (7, 44%) was most frequently encountered. Distressed respiratory sign (8, 50%) was the most common clinical presentation in early onset group, while fever >38 degrees C (17, 100%) was the most common presentation in late-onset group. The mortality rates were 13% and 6% in early and late onset groups, respectively. Gestational age (p = 0.05) and pneumonia (p = 0.015) were two most important factors influencing the mortality rate. CONCLUSIONS: The number of GBS-infected infants seemed to have increased during the past 7 years in our hospital. Because the incidence of neonatal GBS infection and maternal colonization in Taiwan has not been collected, we could not determine the necessity of intrapartum chemoprophylaxis. Setting a comprehensive surveillance in Taiwan should be considered.

Relationship of oral lichen planus to hepatitis C virus in southern Taiwan.

Oral lichen planus (OLP) is a relatively common skin and oral disease that manifests as a mucous reaction to a variety of etiologic factors, including autoimmune disease, drug reaction, diabetes mellitus (DM), hypertension, hepatitis C virus (HCV), urolithiasis, psychogenic factors, and bacterial infection. The purpose of this study was to investigate the relationship between HCV infection and OLP as there is a high prevalence of HCV infection in Taiwan. A total of 1,075 subjects aged at least 15 years participated in the study. The total prevalence of OLP was 3% (32/1,075). OLP was significantly associated with DM (odds ratio, OR, 3.09) and HCV (OR, 2.05). Atrophic-erosive OLP (13/32) and reticular OLP (21/32) were significantly associated with HCV and DM, respectively. Logistic regression analysis showed that elevation of alanine aminotransferase (ALT) significantly increased the risk of atrophic-erosive OLP. We concluded that OLP is significantly associated with HCV and DM in southern Taiwan, particularly in HCV patients with elevated serum ALT levels and atrophic-erosive OLP.

The inverted temporalis muscle flap for intraoral reconstruction: its rationale and the results of its application.

PURPOSE: The purpose of this article was to show the discrepancies among the different parts of the temporalis muscle flap (TMF), to introduce a new rotational arc for the TMF based on these findings, and to examine the outcomes associated with the use of this modified method. MATERIALS AND METHODS: Two models were established on 5 human skulls to mimic the situations with the usual dissection technique or the extended dissection technique for the TMF. The lengths of the anterior part, the middle part, and the posterior part of the flap were measured and analyzed for statistical significance. A new rotational arc for the TMF was introduced, in which the flap was inverted beneath the zygomatic arch, placing the temporalis fascia away from the oral side. Seventeen consecutive oral cancer cases treated with either the traditional method or the inverted method of flap transposition were reviewed and divided into 2 groups dictated by the rotational arcs of their flaps. The traditional TMF was used in 11 cases and the inverted TMF was used in 6 cases. Clinical examination and imaging studies were used for assessment of outcome, and the results from the 2 patient groups were compared. RESULTS: The middle and posterior parts of the temporalis muscle were significantly longer than the anterior part on the skull models. However, the middle and posterior parts did not differ greatly in length. The extended dissection technique increased the flap length except for the anterior part. Both flaps were successful in closing the defects in all cases and healed well. No muscle necrosis was observed. However, the patients receiving the traditional TMF developed noticeable cheek fullness in 4 instances, sialocele in 3, significant reduction of range of mouth opening in 2, and distinct velopharyngeal insufficiency in 2, whereas only 1 case in which the inverted TMF was used developed cheek fullness. CONCLUSIONS: The middle or posterior part of the temporalis flap is preferred over the anterior part for covering distant defects because of its extra length. The inverted TMF is simple and safe to apply. It can extend farther in the posterior oral cavity and has fewer complications than the traditional TMF.

Mutation analysis of X-linked hypohidrotic ectodermal dysplasia in a Taiwanese family.

X-linked hypohidrotic ectodermal dysplasia (XLHED, OMIM 305100) is the most common form among the ectodermal dysplasias, a rare group of hereditary diseases characterized by abnormal development of eccrine sweat glands, hair, and teeth. Heterozygous carriers of XLHED often manifest minor or moderate degrees of hypotrichosis, hypodontia, and hypohidrosis. ED1, the gene involved in XLHED, encodes ectodysplasin A, a new member of the tumor necrosis factor family. The majority of mutations in XLHED are missense mutations, but one-fifth are insertion/deletions. In this report, we describe the mutation analysis of a Taiwanese pedigree with XLHED. A 35-bp deletion in exon 5 of the ED1 gene was found in the 3 affected males and in 5 female carriers. Mutation analysis in families with XLHED allows for genetic counseling, prenatal diagnosis, and confirmation of carrier status.

Nevoid basal cell carcinoma syndrome - clinical manifestations and mutation analysis of a Taiwanese family.

Nevoid basal cell carcinoma syndrome (NBCCS) is a rare pleiotropic autosomal dominant disease predominantly characterized by the occurrence of multiple basal cell carcinomas, odontogenic keratocysts (OKCs) of the jaw, and other developmental defects. Mutations in the human patched gene (PTCH) have recently been detected in patients with NBCCS. We report the clinical manifestations of a Taiwanese family with NBCCS and mutation analysis of the PTCH gene from peripheral blood, OKC tissues, and cyst content. A heterozygous A-to-G transition at nucleotide 3169-2 within the intron 18 (3169-2 A>G) was found. The cystic membrane and the cystic content showed the same results. Mutation analysis can provide a reliable prenatal diagnosis of this syndrome in subsequent pregnancies.