A simple approach to examine early oral microbial biofilm formation and the effects of treatments

BACKGROUND/AIMS: A simple in vivo approach to examine early dental plaque formation in the human mouth and to determine the effects of common dietary and oral hygiene procedures on biofilm formation is reported. METHODS: A custom designed device that fits securely behind the teeth of the mandibular arch provides a surface for microbial colonization. This device is prepared with denture acrylic and can be repeatedly used by the subject, exposing a large and constant surface area for microbial accumulation. RESULTS: Large numbers of oral bacteria colonized the device by 2 h; these increased significantly by 4 h (P < 0.05). Bacterial colonization increased significantly after rinsing with a sucrose solution (P < 0.05) but remained unaffected after rinsing with water, a commercially available fluoride mouthrinse without antimicrobial agents, or brushing with a fluoride dentifrice (P > 0.05). Rinsing with mouthrinses formulated with chlorhexidine, cetylpyridinium chloride or triclosan/copolymer significantly inhibited colonization (P < 0.05). A dose-dependent inhibition was noted with chlorhexidine rinses (P < 0.05). Brushing with a triclosan/copolymer dentifrice significantly inhibited microbial colonization compared with a control (P < 0.05). CONCLUSION: This simple approach was useful for examining the effects of common dietary and oral hygiene procedures. Significant biofilm inhibitory effects were noted with formulations that demonstrated efficacy in previous clinical studies.     

An ex‐vivo multiplexed antibacterial test on oral microflora

Background/aims: Characterized clinical strains of oral bacteria are utilized to examine the antimicrobial efficacy of oral care formulations. A demonstration of antimicrobial effects of formulations on microbial samples obtained from the human mouth offers advantages, i.e. incorporates the considerable microbial diversity of this environment with bacteria harvested from naturally occurring biofilms to form the focus of this investigation. Materials and methods: Samples of oral flora from each adult subject were briefly treated (2 min) with test and control formulations and plated on appropriate agar for multiplexed antimicrobial effects on functional groups of oral bacteria associated with specific conditions. Results: Ex‐vivo treatments of oral samples with the triclosan/copolymer dentifrice demonstrated significant dose‐dependent antimicrobial effects compared with a control formulation on anaerobic and facultative oral bacteria from a group of 16 volunteers (P < 0.05) with reproducible effects observed in three separate trials (P < 0.05). Similarly, significant dose‐dependent effects were noted with chlorhexidine mouthrinses (P < 0.05). A simultaneous assessment of the effects of these formulations on several functional classes of oral bacteria associated with specific oral conditions such as dental caries and oral malodor demonstrated multiplexed antimicrobial activity (P < 0.05). Conclusions: A rapid procedure using small volumes of human oral samples and well‐known formulations demonstrates ex‐vivo multiplexed antimicrobial effects on functional groups of bacteria with both dentifrices and mouthrinses. Modifications of this approach may include antibacterial effects over time with formulations at clinically relevant concentrations, effects of novel agents or samples from subjects stratified on the basis of their clinical status.     

Characterization of reconnecting vortices in superfluid helium

When two vortices cross, each of them breaks into two parts and exchanges part of itself for part of the other. This process, called vortex reconnection, occurs in classical and superfluids, and in magnetized plasmas and superconductors. We present the first experimental observations of reconnection between quantized vortices in superfluid helium. We do so by imaging micrometer-sized solid hydrogen particles trapped on quantized vortex cores and by inferring the occurrence of reconnection from the motions of groups of recoiling particles. We show that the distance separating particles on the just-reconnected vortex lines grows as a power law in time. The average value of the scaling exponent is approximately 1/2, consistent with the self-similar evolution of the vortices.     

A randomized,double-blind clinical study to assess the antimicrobial effects of a cetylpyridinium chloride mouth rinse on dental plaque bacteria

Background: Studies with cetylpyridinium chloride (CPC) mouth rinses that range from 1 use to 6 months of use have documented the clinical efficacy of these formulations on supragingival plaque and gingivitis.Objective: The objective of the present study was to compare the effects of a commercially available mouth rinse containing 0.05% CPC versus a fluoride mouth rinse on the anaerobic bacteria found in dental plaque. Antimicrobial effects on the organisms of the supragingival plaque, a natural biofilm, were determined after 1 use and after 14 days of use of each mouth rinse.Methods: After enrollment, adult subjects from China completed a 1-week washout period and provided baseline samples of supragingival plaque for analysis of anaerobic bacteria. Subjects were randomly assigned to receive a commercially available mouth rinse formulated with 0.05% CPC or a fluoride mouth rinse. Subjects were assigned to each group according to a computer-generated randomization sequence. They were instructed to rinse with 20 mL of either the CPC or the fluoride mouth rinse for 30 seconds. Microbiologic analyses of dental plaque samples were conducted 12 hours after the first use of assigned mouth rinse. Subjects were instructed to continue twice-daily rinsing with their assigned mouth rinse for the next 14 days in addition to brushing their teeth with a commercial fluoride toothpaste. Dental plaque samples for microbiologic analyses were collected on day 15; this was done 12 hours after the final use of the assigned mouth rinses. A dentist conducted oral examinations before each sample collection to evaluate hard and soft tissue health over the course of the study.Results: The study included 117 adults (62 females, mean age, 28.70 years; 55 males, mean age, 30.41 years). Subjects rinsing with the CPC mouthwash (n = 58; mean age, 29.41 years) reported significant reductions in anaerobic bacteria versus those issued the fluoride rinse (n = 59; mean age, 29.61 years) 12 hours after 1 use and 12 hours after 14 days of use (P < 0.001). The mean percent reduction in anaerobic bacteria between the CPC mouth rinse and the fluoride mouth rinse was 29.98% after 1 use and 57.90% after 14 days of use. All enrolled subjects completed the study without any adverse events.Conclusion: Use of the CPC mouth rinse was associated with significant reductions in the anaerobic bacteria of supragingival plaque compared with fluoride mouth rinse use in these adult subjects.     

Annexins in human breast cancer: Possible predictors of pathological response to neoadjuvant chemotherapy

Neoadjuvant chemotherapy is used in women who have large or locally advanced breast cancers. However, up to 70% of women who receive neoadjuvant chemotherapy fail to achieve a complete pathological response in their primary tumour (a surrogate marker of long-term survival). Five proteins, previously identified to be linked with chemoresistance in our in vitro experiments, were identified histochemically in pre-treatment core needle biopsies from 40 women with large or locally advanced breast cancers. Immunohistochemical staining with the five proteins showed no single protein to be a predictor of response to chemotherapy. However, pre-treatment breast cancer specimens that were annexin-A2 positive but annexin-A1 negative correlated with a poor pathological response (p = 0.04, Fisher’s exact test). The mechanisms by which annexins confer chemoresistance have not been identified, but may be due to inhibition of apoptosis. Annexin-A1 has been shown to enhance apoptosis, whilst annexin-A2, by contrast, inhibits apoptosis.     

Anorexia nervosa in boys

The literature on primary anorexia nervosa in the male is reviewed and the case histories of 3 new patients are reported. Most surveys comment on the rarity of the syndrome in the male, with the sex ratio in the range of 1 in 10 to 1 in 20. The patients reported here had certain features in common. All the mothers and fathers were overweight, but obesity was marked only in the fathers, who also showed moderate to severe degrees of alcoholism. The mothers were oversensitive, insecure individuals, and the marriages suffered in proportion to the severity of the husband's alcoholism. Preoccupation with food was observed on home visits. There was overt mutual hostility between each father and anorexic son; the boys showed pronounced obsessional traits in their personalities. Dieting in order to ameliorate real or feared obesity was a first step in the development of the syndrome in each boy. In the past 3 years an equal number of boys and girls (new patients) have been referred for treatment in the psychiatric unit. Speculative reasons for this are discussed.     

An ex-vivo multiplexed antibacterial test on oral microflora

BACKGROUND/AIMS: Characterized clinical strains of oral bacteria are utilized to examine the antimicrobial efficacy of oral care formulations. A demonstration of antimicrobial effects of formulations on microbial samples obtained from the human mouth offers advantages, i.e. incorporates the considerable microbial diversity of this environment with bacteria harvested from naturally occurring biofilms to form the focus of this investigation. MATERIALS AND METHODS: Samples of oral flora from each adult subject were briefly treated (2 min) with test and control formulations and plated on appropriate agar for multiplexed antimicrobial effects on functional groups of oral bacteria associated with specific conditions. RESULTS: Ex-vivo treatments of oral samples with the triclosan/copolymer dentifrice demonstrated significant dose-dependent antimicrobial effects compared with a control formulation on anaerobic and facultative oral bacteria from a group of 16 volunteers (P < 0.05) with reproducible effects observed in three separate trials (P < 0.05). Similarly, significant dose-dependent effects were noted with chlorhexidine mouthrinses (P < 0.05). A simultaneous assessment of the effects of these formulations on several functional classes of oral bacteria associated with specific oral conditions such as dental caries and oral malodor demonstrated multiplexed antimicrobial activity (P < 0.05). CONCLUSIONS: A rapid procedure using small volumes of human oral samples and well-known formulations demonstrates ex-vivo multiplexed antimicrobial effects on functional groups of bacteria with both dentifrices and mouthrinses. Modifications of this approach may include antibacterial effects over time with formulations at clinically relevant concentrations, effects of novel agents or samples from subjects stratified on the basis of their clinical status.     

Are People Aware of Oral and Maxillofacial Surgery in India?

Introduction  

Maxillofacial surgery is one of the most rapidly expanding specialities in India. There is however a very poor understanding of the scope of the speciality. This paper attempts to find out the awareness of the speciality in India.