In Vitro Red Fluorescence as an Indicator of Caries Lesion Activity.

This in vitro study examined the utility of comparing red fluorescence between active and inactive caries lesions and investigated whether changes in red fluorescence and fluorescence loss are influenced by lesion activity following remineralization. Sixty-two noncavitated smooth surface caries lesions on extracted human teeth were classified into active or inactive lesions using the Nyvad system prior to a 12-day pH-cycling procedure. Quantitative light-induced fluorescence-digital images were used to measure fluorescence parameters before and after pH cycling. At baseline, the intensity (ΔR) and area (AΔR) of red fluorescence were 1.5- and 2.2-fold higher in active lesions than in inactive lesions (p<0.05). The ratio of AΔR to lesion area was associated with classification of active lesions (odds ratio = 1.031; 95% confidence interval = 1.005-1.058). After pH cycling, the active lesions showed about 2- and 8-fold greater reductions in the median values of AΔR and fluorescence loss related to lesion volume (ΔQ) compared with inactive lesions (p<0.05). In conclusion, red fluorescence differs depending on lesion activity, and the red fluorescence area and lesion volume change following remineralization. The results suggest that measuring red fluorescence may be a useful way of objectively evaluating lesion activity of smooth surface lesions.

Evaluation of the bristle end-rounding patterns of children's toothbrushes using scanning electron microscopy and stereomicroscopy.

OBJECTIVES: The aim of this study was to evaluate the proportions of end-rounded bristles via observations of the end patterns of various children's toothbrushes with scanning electron microscopy (SEM) and stereomicroscopy. METHODS: Ten different brands of children's toothbrushes were chosen, and tufts from each toothbrush were used. The prepared bristle specimens were observed on SEM and stereomicroscopic images and classified as acceptable (A1-A3) and non-acceptable (N1-N5) according to the modified classification. Then, the proportions of end-rounded bristles were calculated. RESULTS: Analyses of the 10 toothbrushes revealed that the proportions of acceptable end-rounded bristles ranged from 1.4% to 20.2% on SEM and from 0.0% to 18.0% on stereomicroscopic examinations. Additionally, some toothbrushes had labels that indicated bristle end-rounding, but the proportions of end-rounded bristles were low. CONCLUSIONS: The types and percentages of bristle ends of children's toothbrushes marketed in Korea were various, but the amount of acceptable end-rounded bristles was low. The result, that even toothbrushes labelled as end-rounded had potential to harm oral tissue, demonstrates that quality control for rounding bristle ends as well as the labelling for end-rounded bristles is needed.

Comparison of the oral microbiome of siblings using next-generation sequencing: a pilot study.

OBJECTIVE: The purpose of this study was to compare the oral microbiome of siblings with and without dental caries using next-generation sequencing. MATERIALS AND METHODS: To investigate the oral microbiome composition, 14 young siblings, seven with caries and seven without, were enrolled from seven sibling-pair families. Supragingival plaque samples were collected from the cervicobuccal area of posterior teeth. All samples were analyzed by pyrosequencing, based on the 16S rRNA gene hypervariable regions, V1-V4. RESULTS: The organisms identified belonged to 65 genera. Fifty-two genera were identified in the subjects with caries and 58 in those without; 45 genera were shared by both groups. In the Shannon index, the caries group showed lower bacterial diversity than the caries-free group and the difference was significant (Wilcoxon signed-rank test, P < 0.05). Additionally, similarities between siblings were evident in analyses based on weighted UniFrac distances (P < 0.05). CONCLUSIONS: In this study, the diversity of the microbiome was reduced in subjects with dental caries, while similarity between siblings seemed to be retained.

Evaluation of penetration effect of resin infiltrant using optical coherence tomography.

OBJECTIVE: The aims of this in vitro study were to investigate whether optical coherence tomography (OCT) could analyze infiltration of resin infiltrant (RI) into early dental caries (EC), and to confirm the correlation between the results of OCT and confocal laser scanning microscopy (CLSM) for evaluation of RI infiltration into EC. METHODS: Sound bovine permanent teeth were used to produce sixty specimens by making two windows on the teeth. Each 20 specimens were demineralized for 20, 30, and 40 days, and the RI was treated on one of the windows. As a result, the images of the fifty-two specimens were taken by OCT and CLSM. The demineralized lesion depth (LDOCT and LDCLSM) and the infiltrated depth of RI into lesion (IDOCT and IDCLSM) obtained from the OCT and the CLSM were analyzed. The correlations between the LDOCT and the LDCLSM, and between the IDOCT and the IDCLSM, were analyzed by Pearson correlation and intra-class correlation. Also, Bland-Altman plot was constructed to assess the agreement between the IDOCT and the IDCLSM, and the IDOCT divided by refractive index of RI and the IDCLSM. RESULTS: The Pearson correlation coefficient and intra-class correlation of 0.75 and 0.83 (95% CI: 0.71-0.91) respectively were confirmed between the LDOCT and the LDCLSM (p<0.001), and 0.59 and 0.71 (95% CI: 0.50-0.84) respectively were observed between the IDOCT and the IDCLSM (p<0.001). The lower bias was confirmed in Bland-Altman plot between adjusted IDOCT and the IDCLSM than between the IDOCT and the IDCLSM. CONCLUSION: The OCT was the promising quantitative evaluation method for RI penetrated into EC. CLINICAL SIGNIFICANCE: The OCT would be used as a nondestructive and real-time evaluation method for RI penetrated into EC on clinical procedure.

Assessment of masticatory function in patients with non-sagittal occlusal discrepancies.

Non-sagittal occlusal discrepancies such as posterior cross-bite and anterior openbite are common types of malocclusion, but studies on masticatory function related to those malocclusions have been scarce. The aim of this study was to quantify the masticatory performance in patients with non-sagittal discrepancies compared to those with normal occlusion, using both objective and subjective measures. Maximum bite force and contact area using Dental Prescale(®) system as a static objective assessment, Mixing Ability Index (MAI) as a dynamic objective evaluation and food intake ability (FIA) as a subjective assessment were analysed from 21 people in normal occlusion (Group N) and 64 patients with posterior cross-bite (Group C), anterior openbite (Group O) or both (Group B). The differences of the maximum bite force, the contact area, the MAI and the FIA were compared, and their correlations were figured out. The non-sagittal malocclusion groups showed lower values in the maximum bite force, the contact area, the MAI and the FIA compared to those in the normal group (P < 0·0001). Compared to Group N, Groups C, O and B showed 61·5%, 42·1% and 40·1% of the maximum bite force, and 84%, 84% and 76% of hard food FIA, respectively. However, there were no significant differences among Groups C, O and B. The MAI showed higher correlation with the FIA (r = 0·38, P < 0·01), than with the maximum bite force and the contact area (both r = 0·24, P < 0·5). These results revealed that masticatory function in patients with non-sagittal discrepancies is significantly reduced both objectively and subjectively.

Outbreak among healthy newborns due to a new variant of USA300-related meticillin-resistant Staphylococcus aureus.

BACKGROUND: The prevalence of community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) is increasing throughout the world and is an important cause of skin and soft tissue infection (SSTI) in children and neonates. AIM: To describe the successful control of an outbreak caused by a new strain of CA-MRSA in a newborn nursery. METHODS: The investigation of the outbreak in July 2012 is reported with the control measures taken. Molecular typing of the MRSA isolates was performed. FINDINGS: An outbreak of SSTI caused by CA-MRSA occurred in a newborn nursery. Six neonates were infected in a one-month period [infection rate: 8.5% (6/71)]. A new variant of CA-MRSA was responsible, which was characterized as USA300-related, Panton-Valentine Leucocidin (PVL) positive, arginine catabolic mobile element (ACME) negative, sequence type 8 (ST8), staphylococcal cassette chromosome mec (SCCmec) type IVa, agr type I and spa type t008. The outbreak among term neonates followed a rapid transmission pattern and was successfully controlled by implementing various outbreak control measures, including universal chlorhexidine bathing. CONCLUSION: This is the first report of a hospital outbreak caused by a USA300-related CA-MRSA clone in Korea. Early recognition and reinforcement of infection control measures are important in decreasing transmission of CA-MRSA in a hospital setting.

A conceptual model for the impact of climate change on fox rabies in Alaska, 1980-2010.

The direct and interactive effects of climate change on host species and infectious disease dynamics are likely to initially manifest\ at latitudinal extremes. As such, Alaska represents a region in the United States for introspection on climate change and disease. Rabies is enzootic among arctic foxes (Vulpes lagopus) throughout the northern polar region. In Alaska, arctic and red foxes (Vulpes vulpes) are reservoirs for rabies, with most domestic animal and wildlife cases reported from northern and western coastal Alaska. Based on passive surveillance, a pronounced seasonal trend in rabid foxes occurs in Alaska, with a peak in winter and spring. This study describes climatic factors that may be associated with reported cyclic rabies occurrence. Based upon probabilistic modelling, a stronger seasonal effect in reported fox rabies cases appears at higher latitudes in Alaska, and rabies in arctic foxes appear disproportionately affected by climatic factors in comparison with red foxes. As temperatures continue a warming trend, a decrease in reported rabid arctic foxes may be expected. The overall epidemiology of rabies in Alaska is likely to shift to increased viral transmission among red foxes as the primary reservoir in the region. Information on fox and lemming demographics, in addition to enhanced rabies surveillance among foxes at finer geographic scales, will be critical to develop more comprehensive models for rabies virus transmission in the region.

Changes in masticatory function after injection of botulinum toxin type A to masticatory muscles.

This study examined changes in masticatory function after botulinum toxin type A (BTX-A) injection using objective and subjective tests during 12 weeks. Also, we compared differences in masticatory function between group in which only masseter muscle (M group) was injected and group in which masseter and temporal muscle (M-T group) were injected. Forty subjects were assigned into two groups; M group (n = 20) and the M-T group (n = 20). The Meditoxin(®) was used as BTX-A injection. The mixing ability index (MAI) was used as the objective indicator, and visual analogue scale (VAS) and food intake ability (FIA) index were used as subjective indicators. Overall, the masticatory function drastically declined after 4 weeks and gradually recovered with time. Compared with the pre-injection state, the masticatory function decreased by 89·2% (MAI), 12·2% (FIA) and 32·2% (VAS) 4 weeks after the injection (P < 0·05). When the results between M group and M-T group were compared, scores of VAS and FIA were significantly different 4 weeks after the injection (P < 0·05), but the MAI score showed no significant difference between two groups. In conclusion, this study showed that masticatory function was significantly decreased after BTX-A injection into the masticatory muscle after 4 and 8 weeks from injection. However, masticatory efficiency measured using MAI could completely recover after 12 weeks. Furthermore, after 8 weeks from the injection, the masticatory function measured after injection into only the masseter muscle was similar to that measured after injection into both masseter and temporal muscle.

Effect of nano-carbonate apatite to prevent re-stain after dental bleaching in vitro.

OBJECTIVES: This study examined the effect of nano-carbonate apatite (n-CAP) to prevent re-staining and the change of enamel surface after dental bleaching in vitro. METHODS: Twenty-four bovine specimens were bleached for 2 weeks with 10% carbamide peroxide (CP). After bleaching, the specimens were divided into the following four groups: distilled and deionized water (DDW, negative control), 10% n-CAP, NaF (positive control) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, positive control). Each group was subjected to pH cycling for 7 days. The specimens were treated for 4 min 3 times per day and re-staining was induced naturally by artificial saliva in the remineralization process. After pH cycling, the changes in colour were evaluated with spectrophotometry and scanning electron microscopy (SEM). The difference in colour between before and after pH cycling was evaluated using an ANOVA and Tukey test. RESULTS: After pH cycling, the colour difference of n-CAP group was significantly lower than that of the DDW and CPP-ACP groups (p<0.05). SEM showed that n-CAP particles were deposited regularly on the damaged surface compared to the other groups. CONCLUSION: 10% n-CAP could significantly maintain the initial colour and protect the damaged enamel structure after bleaching.

The addition of nano-sized hydroxyapatite to a sports drink to inhibit dental erosion: in vitro study using bovine enamel.

OBJECTIVES: This study examined the dental erosion and demineralization potential of a sports drink containing nano-sized hydroxyapatite (nano-HA) as an additive. METHODS: The experimental solutions were Powerade (PA) alone and PA with 0.05%, 0.10%, and 0.25% nano-HA. The pH, titratable acidity, and calcium and phosphate content of each solution were analysed, and the degree of saturation with respect to the dental enamel (DS(En)) was obtained. Twelve sound bovine enamel specimens for each group were treated in accordance with the pH-cycling schedule which had 60min treatment with experimental solution per day for 7 days. The erosion potential was determined from the changes in surface micro hardness (SMH), the depths of erosion and demineralized layer using confocal laser scanning microscopy (CLSM), and the morphological changes to the tooth surface were examined with scanning electron microscopy (SEM) after pH-cycling. RESULTS: pH and DS(En) increased with increasing nano-HA concentration in the drinks, whereas the titratable acidity decreased. There were significant differences in the SMH between the PA alone and >0.10% nano-HA groups (p<0.001). Although the PA alone group showed a pronounced erosion depth, CLSM showed no erosion depth in 0.25% nano-HA group. SEM showed an intact surface with increasing nano-HA concentration in the drinks. In conclusion, dental erosion was effectively prevented with increase of adding concentration of nano-HA, and a sports drink containing 0.25% nano-HA might prevent dental erosion.

Objective and subjective assessment of masticatory function for patients with temporomandibular disorder in Korea.

This study examined the differences in the masticatory function of patients with temporomandibular disorder (TMD) in Korea. The experimental groups were as follows: 23 patients with painful arthralgia classified as pain group according to the research diagnostic criteria for temporomandibular disorder (RDC/TMC) and 28 patients with pain-free disc displacement and reduction classified as clicking group. The subjects were obtained from those who had visited Yonsei University Dental Hospital from 2007 to 2008. Twenty dental students without TMD symptoms were enroled as the normal control group. The Mixing Ability Index (MAI) was used as the objective index, and the Food Intake Ability (FIA) Index, Visual Analogue Scale (VAS) and oral health impact profile (OHIP) were used as the subjective indices. The MAI, FIA and VAS were significantly lower in the pain group than in the normal and clicking groups (P<0·05). The pain group showed a MAI, FIA and VAS of 16%, 81% and 67%, respectively, compared to that of the normal group. However, there were no significant differences in the MAI, FIA and VAS between the clicking and normal groups. The pain and clicking groups showed a 1·7 and 1·4 times higher OHIP value than the normal group (P<0·05). The MAI and subjective indices, such as the FIA (r=0·40) and VAS (r=0·48), showed a moderate correlation (P<0·01). In conclusion, pain is the main factor for the reduced masticatory function in patients with TMD in Korea, and the joint sound, not the masticatory function, affects the declining OHIP.

Subjective food intake ability in relation to the Mixing Ability Index in Korean adults.

This study examined the association between the subjective food intake ability (FIA) using a questionnaire with 30 types of foods and the objective Mixing Ability Index (MAI) using a two-coloured wax cube. A total of 147 subjects (32 males, 115 females, mean age: 54.9 +/- 20.7) were enrolled in this study. The FIA for 30 food types and the key food intake ability (KFIA) for five key food types were obtained using a self-assessed questionnaire to evaluate the subjective chewing ability. The objective chewing ability was evaluated by asking the subjects to chew a wax cube for 10 strokes. The MAI was calculated by image analysis of the chewed wax cube. The Pearson's correlation between the subjective FIA and objective MAI was analysed according to age and number of post-canine teeth lost. The FIA for the 30 foods and five key food types showed a moderate correlation with the MAI (r = 0.51, 0.55, respectively, P < 0.01). The KFIA of the denture wearing group (r = 0.44, P < 0.01) and over 60-year-old group (r = 0.49, P < 0.01) showed a significantly higher correlation with the MAI than the other groups. In conclusion, there was a moderate correlation between the subjective FIA and objective MAI in Korean adults.

Impact of non-alcoholic fatty liver disease on microalbuminuria in patients with prediabetes and diabetes.

BACKGROUND: It is unknown whether microalbuminuria is associated with non-alcoholic fatty liver disease (NAFLD) among patients with prediabetes and type 2 diabetes mellitus (DM). This study investigated the association of NAFLD with microalbuminuria among patients with prediabetes and diabetes. METHODS: We evaluated 1361 subjects who had an abnormal oral glucose tolerance test (OGTT) on routine screening. All participants were divided into two groups, prediabetes and newly diagnosed type 2 DM, and the association of NAFLD with metabolic parameters on microalbuminuria was analysed. RESULTS: The patients with NAFLD had higher prevalence rates of microalbuminuria (6.3% vs 19%; P = 0.001 in prediabetes, 4.5% vs 32.6%; P < 0.001 in diabetes) and also had a greater albumin-to-creatinine ratio (14.6 +/- 52.0 microg/mg Cr vs 27.7 +/- 63.9 microg/mg Cr; P = 0.051 in prediabetes, 11.4 +/- 21.4 microg/mg Cr vs 44.7 +/- 76.4 microg/mg Cr; P < 0.001 in diabetes) than those without NAFLD. The logistic regression analysis showed that NAFLD was associated with increased rates of microalbuminuria (odds ratio 3.66; 95%confidence interval (CI) 1.31-10.20, P = 0.013 in prediabetes, odds ratio 5.47;95% CI 1.01-29.61, P = 0.048 in diabetes), independently of age, sex, body mass index, waist circumference, liver enzymes, lipid profiles, HbA1c, insulin resistance as estimated by homeostasis model assessment, hypertension,smoking status and the metabolic syndrome. CONCLUSIONS: The results of our study revealed a strong relationship between microalbuminuria and NAFLD in the patients with prediabetes and newly diagnosed diabetes. Further studies are required to confirm whether NAFLD is a predictor of the development of microalbuminuria in patients with prediabetes and diabetes.

Change of insulin sensitivity in hepatitis C patients with normal insulin sensitivity: a 5-year prospective follow-up study variation of insulin sensitivity in HCV patients.

BACKGROUND: Hepatitis C virus (HCV) infection is associated with a high prevalence of diabetes mellitus (DM). Insulin resistance (IR) is known to play a crucial role in the development of DM in chronic hepatitis C (CHC) patients. We prospectively investigated changes of insulin sensitivity in CHC patients during a 5-year period and analysed the factors significantly associated with IR. METHODS: Sixty-two CHC patients with normal insulin sensitivity (CHC group), and a healthy control group of 172 subjects matched by age, gender, body mass index and lifestyles were studied. We compared the initial baseline insulin sensitivity, metabolic parameters and incidence of IR at the end of the follow-up period between the two groups. The changes in insulin sensitivity, metabolic parameters and the development of IR were analysed as well as factors associated with the development of IR. RESULTS: IR developed in 22.5% of 62 CHC patients and 5.2% of 172 normal individuals (P < 0.001). HCV infection per se and the genotype 1 were independent risk factors for the development of IR. The duration of infection > or = 120 months, initial fasting glucose 90-100 mg/dL, fasting insulin > or = 10 microIU/mL and the homeostasis model assessment (HOMA-IR) 2.3-2.7 were significantly associated with the development of IR in the CHC group. CONCLUSION: HCV infection was an independent risk factor for the development of IR. All CHC patients, even those with normal insulin sensitivity, require careful monitoring for the development of IR.

Application of fluoride iontophoresis to improve remineralization.

Iontophoresis is generally used to maximize the therapeutic action of drugs in medicine. This technique can be used to improve the remineralization effect of topical fluoride applications in dentistry. The aim of this study was to compare the remineralization effect of fluoride iontophoresis (FI) with the conventional fluoride application (CFA) method in vitro. Sixty bovine enamel specimens were divided into three groups: no fluoride treatment, CFA and FI. Fluoride was applied to the demineralized specimens for 4 min in each experimental group. The types of fluoride system used for application were 1.23% acidulated phosphate fluoride gel (12 300 p.p.m. F, pH 3.5) and 2% sodium fluoride solution (9050 p.p.m. F, pH 7) in the experimental groups. All the specimens were then placed in a remineralizing solution for 24 h. This cycle was repeated five times. An iontophoresis device (0.4 mA, 12 V) was used in the FI groups. The efficacy of this technique was evaluated by measuring changes in the surface microhardness and lesion depth of the specimens using confocal laser scanning microscope (CLSM). Data were analysed using anova and Tukey's post hoc test (P < 0.05). Although the FI groups showed higher DeltaVHN than the CFA groups, there were no significant differences between these fluoride application methods (P > 0.05). When the lesion depth was measured using CLSM imaging, there was also no significant difference between the FI and CFA groups (P > 0.05). In conclusion, FI was not significantly superior to CFA in terms of the remineralization effect.

Subjective food intake ability in relation to maximal bite force among Korean adults.

This study examined the relationship between the subjective food intake of 30 food types and their objective bite force to identify the key food items within the 30 food types to achieve a greater depth of masticatory function in Korean adults. A sample of 308 (112 males and 196 females) adults over the age of 20 (average age, 48.6) was selected among patients who visited four dental hospitals in Seoul, Korea. The subjective masticatory ability was evaluated through an interview with food intake ability questionnaires consisting of 30 food types ranging from hard to soft using a five-step Likert scale. The objective maximal bite force was measured using pressure-sensitive films. The relationship between the food intake ability and bite force was analysed and stratified according to age, gender, number of post-canine teeth lost and several clinical oral health indicators. The key foods were selected using correlation and factor analysis. The subjective food intake ability between the 30 foods and key foods were tested by cluster and one-way anova analysis. The Pearson's correlation coefficient between food intake ability and bite force was 0.45 (P < 0.01). The five key food items selected were dried cuttlefish, raw carrot, dried peanut, cubed white radish kimchi and caramel. The correlation coefficient between the food intake ability and bite force of these items was 0.51 (P < 0.01). These results suggest that the subjective food intake ability using the 30 and five key foods can be used to evaluate the masticatory function in Korean adults.

Effect of dentinal tubule occlusion by dentifrice containing nano-carbonate apatite.

This study evaluated the effects of the short-term use of a dentifrice containing nano-sized carbonate apatite (n-CAP) on the occlusion of the dentinal tubules using a scanning electron microscope (SEM) and an image analyser in vitro. One hundred human dentine specimens were wet ground with a silicone carbide papers and etched with 6% citric acid for 1 min to allow complete opening of the dentinal tubule. Specimens showing complete opening tubules were used as the baseline. The specimens were divided randomly into five groups: G1: 0% n-CAP, G2: 5% n-CAP, G3: 10% n-CAP, G4: 20% n-CAP and G5: 10%strontium chloride (SrCl(2)). Five specimens from each group were brushed by applying 50, 100, 250 and 500 strokes, respectively. All the specimens were evaluated by a SEM (x3000), and the degree of occlusion of the dentinal tubules was quantified using an image analyser. The results were analysed by one-way anova and a Tukey's test using the spss 12.0 statistical package program. The dentifrice containing 20% n-CAP for 50 strokes, which indicated 2-day use, showed the highest tubular occlusion than the other groups (P < 0.05). Moreover, this group showed 79.5% and 77.4% less open tubular area than the baseline and 0% n-CAP group, respectively. The groups containing various concentrations of n-CAP showed significant differences in the SrCl(2) group after tooth-brushing for 500 strokes, which indicated 17-day use. According to this examination of the short-term use of desensitizing dentifrices in vitro, the dentifrice containing 20% n-CAP was the most effective in occluding the dentinal tubules.

Evaluation of dual priming oligonucleotide-based multiplex PCR for detection of HBV YMDD mutants.

We evaluated the usefulness of dual priming oligonucleotide (DPO)-based multiplex PCR, Seeplex HBV Lami-DR assay (Seegene Institute of Life Sciences, Seoul, Korea), to detect lamivudine-resistant HBV mutants in a comparison with the use of TRUGENE HBV genotyping and restriction fragment mass polymorphism (RFMP). Sera from 44 chronic hepatitis B patients were analyzed for the presence of mutations at codons 180 and 204 by performing DPO-based multiplex PCR, RFMP, and TRUGENE. The overall concordance rate among the three assays was 40.9% (18/44). Concordance rates between multiplex PCR and RFMP or multiplex PCR and TRUGENE were 61.4% (27/44) and 50.0% (22/44), respectively. In ten patients, multiplex PCR identified additional mutants not found using the other two methods. DPO-based multiplex PCR is a highly sensitive method to identify minor mutant populations and could be a practical tool in the monitoring of lamivudine resistance.

Quality and effect of single dose versus split dose of polyethylene glycol bowel preparation for early-morning colonoscopy.

BACKGROUND AND STUDY AIMS: The conventional procedure of ingestion of an entire dose of polyethylene glycol solution on the day before early-morning colonoscopy may result in poor bowel preparation. The aim of this study was to evaluate the efficacy and effect of a split-dose ingestion of polyethylene glycol for early-morning colonoscopy. METHODS: A total of 303 age- and sex-matched consecutive individuals presenting for medical check-ups were randomly assigned to receive either 4 L of polyethylene glycol solution with a soft diet on the day before colonoscopy (n = 152; group A), or 3 L of polyethylene glycol solution with a soft diet on the preceding day and then 1 L of the solution on the day of colonoscopy (n = 151; group B). The quality of bowel preparation was evaluated using the Ottawa scale, and the time to cecal intubation and the technical difficulty during the procedure were also recorded. RESULTS: There was no difference in compliance between group A (single-dose) and group B (split-dose). The quality of bowel preparation was better in group B compared with group A. When the participants were categorized according to compliance (good compliance, 116 in group A, 119 in group B; poor compliance, 36 in group A, 32 in group B), the quality of the bowel preparation had a higher score in the good compliance compared with the poor compliance group, and in group B this difference was usually significant. CONCLUSIONS: Split-dose bowel preparation with polyethylene glycol solution provided a better quality preparation than the conventional method for patients undergoing early-morning colonoscopy.

Vertical profile of algal distribution during aeration prior to intake tower for safe drinking water.

Blue-green algae or cyanobacteria comprise a diverse group of organisms, all of which generate potent natural toxins, as well as characteristic odours. In particular, blue-green algae, such as Microcystis and Anabaena, are often detected abundantly in surface water used as a drinking water resource. In order to confirm our ability to provide safe drinking water even during a water bloom, we have conducted an investigation into the vertical distribution of algae during aeration prior to entry into the intake tower at a dam site. Our analysis of the vertical algal distribution during aeration indicated that aeration occurring at the intake tower exerts a significant influence on the safety of the drinking water. It was determined that the discontinuation of aeration and an increase in the depth at which water intake is conducted, constitutes a viable strategy for the maintenance of toxin- and odour-free drinking water, particularly during water bloom events.