A study to correlate various facial landmarks with intercanine distance

Context

Ideal interaction of dental and facial beauty proportions highly influences a harmonious facial appearance. Racial anatomical variations have been significantly noted and using these norms during prosthodontic rehabilitation will be greatly helpful in successful treatment outcome.

Aim

The present study aims to correlate various facial landmarks (interpupillary distance [IPD], intercanthal width, bizygomatic width [BZW], and interalar width) with intercanine distance (ICaD) in Indian young adults to determine the mesiodistal width of the maxillary anterior teeth in edentulous patients.

Setting and Design

This is an observational cross-sectional study.

Materials and Methods

This study was conducted in 500 individuals ranging in age from 18 to 28 years. IPD, intercanthal width, BZW, and interalar width were measured with a digital caliper (accuracy - 0.01 mm). A "T-" shaped flat metal plate called "canine tip marker" was made to mark the tips of the maxillary canines, which were further measured with the digital caliper. The data were summarized in table form and were statistically analyzed.

Statistical Analysis Used

Student's t-test and ANOVA test were used.

Results

A significant correlation (P < 0.001) was found between these landmarks with ICaD, in which interalar width shows highest degree of correlation (r = 0.639). ANOVA test showed that maximum number of individuals had < 5% variability range between actual values and calculated values of ICaD for all extraoral facial landmarks except intercanthal width.

Conclusion

Combination of various facial and oral factors should be considered while selecting artificial teeth. Regression equations obtained can be well used during teeth selection to achieve a significant result.

High xylan recovery using two stage alkali pre-treatment process from high lignin biomass and its valorisation to xylooligosaccharides of low degree of polymerisation

In the present work, xylan from arecanut husk was extracted using 2 stage alkaline pretreatment process. In first step, biomass was incubated in alkali at different temperatures (25 °C, 50 °C and 65 °C), alkali concentrations (5%, 10%, 15% and 20% w/v), and incubation periods (8 h, 16 h and 24 h) and evaluated for xylan recovery. It was observed that 40-52% of available xylan could be recovered using 10% alkali when incubated for 8-24 h at 65 °C. Subsequently, the alkali pretreatment operating conditions which provided good xylan recovery were processed further using hydrothermal treatment to extract more xylan. For maximum xylan recovery (>90%), best operating conditions were identified when biomass was treated under hydrothermal treatment (1, 1.5 and 2 h) with varying incubation periods (8, 16, 24 h) and alkali concentrations (5%, 10%) using full factorial design. Incubating arecanut husk with 10% w/v NaOH, at 65 °C for a period of 8 h, followed by hydrothermal treatment at 121 °C for 1 h helped recover >94% xylan. In the next step, enzymatic hydrolysis process was optimized to recover maximum XOS (Optimized condition: 50 °C, pH 4 and 10 U enzyme dose). The hydrolysate comprised of xylobiose: 25.0 ± 1.2 g/100 g xylan (∼71% of XOS), xylotriose: 9.2 ± 0.65 g/100 g xylan (26.2% of XOS) and xylotetrose: 0.9 ± 0.04 g/100 g xylan (2% of XOS). The developed process enables to reduce alkali consumption for high recovery of xylan from biomass with relatively higher lignin content for its valorisation into a potential prebiotic oligosaccharide.

Clinical implications of p53 alterations in oral cancer progression: a review from India

p53 plays a central role in prevention of normal cell from the development of the malignant phenotype. Somatic alterations (mutations, loss of heterozygosity, deletions) in p53 are a hallmark of most human cancers and cause defects in normal p53 function. However, in the tumors harboring wild-type p53, there are alterations in the regulation of the p53. Thus, understanding why p53 is unable to perform its role as a tumor suppressor in these wild-type tumors is very crucial. Germ-line polymorphisms in p53 are also anticipated to cause measurable disturbance in p53 function. Over-expression as well as polymorphic variants of MDM2 might have effects on cancer development. In addition, degradation of p53 by E6 protein of high risk human papillomavirus is also suggested as one of the mechanisms which attenuate p53 responses in oral carcinogenesis. p53 has also been demonstrated to mediate cellular responses upon various DNA damaging cancer therapies, importantly, apoptosis. These responses have been implicated in an individual's ability to respond to these cancer therapies. Thus, exploring mechanisms by which normal function of p53 is affected in the comprehensive way in oral cancer might aid in the identification of tumor characteristics, prognosis and thus in the development of a new approach to treat the oral cancer.

An Integrated Approach for Cosmetic Rehabilitation of a Patient with Atrophia bulbi

Atrophia bulbiis a small, shrunken, non-functional eye, most commonly due to trauma. It represents an ocular end-stage disease characterized by atrophy, shrinkage, and disorganization of the eyeball and intraocular contents, demonstrating the result of failed previous ocular therapy in which restoration of the morphologic and functional integrity of the eye is not possible. Majority of the patients with Atrophia bulbi eventually become blind and cosmetically unacceptable. The rehabilitation of such patients presents a challenging clinical situation, as the patient has already been clouded by the psychological distress. This paper demonstrates a case of 35-year male with Atrophia bulbi, who was successfully rehabilitated with precisely fabricated ocular prosthesis fitted over the atrophic eye.

Maxillary canine transposition - A literature review with case report

Tooth transposition is a severe disturbance of tooth eruptive position and their sequence, which involve certain teeth occurring at any of several specific sites in the mouth. Tooth transposition is of several types and their classification depends on the teeth involved. The review of literature aims to discuss the incidence and identifying factors related to occurrence of this dental anomaly. The present study aims to discuss about the prosthetic treatment of a patient with unilateral maxillary canine - lateral incisor transposition with the absence of permanent lateral incisor.

Three-dimensional quantitative analysis of the bone density of mandibular condyle in dentulous and edentulous jaws: an in vivo study

Studies have reported that masticatory function and occlusal force are low in edentulous patients, which brings about a change in the density, thickness, and alignment of bony trabeculae. However, studies that have quantitatively measured the differential cortical and medullary bone densities of the mandibular condyle in vivo remain rare. This study determined and compared the cortical and medullary bone density of the mandibular condyle in dentulous and edentulous jaws, using multidetector computed tomography (CT). Forty mandibular condyles with no clinical signs of temporomandibular disorders were investigated in 2 groups with 10 subjects (aged 50-80 yr) in each group (group I: dentulous subjects with maintained occlusion; group II: completely edentulous patients) with multidetector CT. The density of condylar cortical and medullary bone was determined by using bone density analysis algorithms available within the proprietary software. Data were analyzed statistically with the 1-way analysis of variance test (p<0.05). The mean cortical bone density of the right and left condyles of group I was 686.11±102.78 Hounsfield unit (HU) and 775.91±89.62 HU, respectively and that of group II was 531.33±289.73 HU and 648.53±294.39 HU, respectively. The mean medullary bone density of the right and left condyles was maximum in group I subjects (429.69±102.62 HU and 486.62±108.60 HU, respectively) than in group II subjects (214.89±104.37 HU and 205.36±90.91 HU, respectively) with a statistically significant decrease in the mean scores (p<0.001). Within the limitations of this study, it can be concluded that the cortical and medullary densities of the mandibular condyle are more in dentulous than the edentulous jaws.

High performance liquid chromatographic determination of residual monomer released from heat-cured acrylic resin. An in vivo study

PURPOSE

Heat-polymerized acrylic resins are used in dentistry for complete denture fabrication. Despite the polymerization method, conversion of monomer into polymer is often incomplete with free or unreacted residual monomer remaining in the polymerized resin. The aim of this study was to determine the amount of residual monomeric methyl methacrylate (MMA) leaching in the saliva of patients wearing complete dentures in their postinsertion period.

MATERIALS AND METHODS

Thirty edentulous participants as first-time complete denture wearers (age 60 to 65 years) were selected. All the prostheses were fabricated using a similar standard technique with a heat-cured acrylic resin denture base material. Saliva samples were collected at time intervals of 1 hour, 1 day, and 3 days postdenture insertion. Participants were asked to discharge saliva every 30 seconds into a pre-weighed screw-capped container for a 5-minute period. MMA levels were measured using high performance liquid chromatography. Data were analyzed by ANOVA and Tukey-HSD.

RESULTS

The maximum concentration of monomer released into saliva peaked 1 day after insertion of the complete dentures. The mean (SD) MMA content was 0.04 ± 0.01 (μg/ml) 1 hour after insertion, and 0.3 ± 0.09 (μg/ml), and 0.05 ± 0.01 (μg/ml) on the first and third days postinsertion, respectively.

CONCLUSIONS

Although the released monomeric MMA was not at toxic levels, it could potentially sensitize complete denture patients or elicit an allergic reaction. The risk of the residual material as a primary irritant for a sensitizing reaction could be minimized by immersion of the denture in water for 24 hours before insertion.

Mercury and other biomedical waste management practices among dental practitioners in India

OBJECTIVES

The objective of the study was to assess the awareness and performance towards dental waste including mercury management policy and practices among the dental practitioners in North India.

MATERIALS AND METHODS

An epidemiologic survey was conducted among 200 private dental practitioners. The survey form was composed of 29 self-administered questions frame based on knowledge, attitude, and those regarding the practices of dentists in relation to dental health-care waste management. The resulting data were coded and a statistical analysis was done.

RESULTS AND DISCUSSION

About 63.7% of the dentists were not aware of the different categories of biomedical waste generated in their clinics. Only 31.9% of the dentists correctly said that outdated and contaminated drugs come under cytotoxic waste. 46.2% said they break the needle and dispose of it and only 21.9% use needle burner to destroy it. 45.0% of the dentists dispose of the developer and fixer solutions by letting them into the sewer, 49.4% of them dilute the solutions and let them into sewer and only 5.6% return them to the supplier. About 40.6% of the dentists dispose of excess silver amalgam by throwing it into common bin.

CONCLUSION

It was concluded that not all dentists were aware of the risks they were exposed to and only half of them observe infection control practices.

Phenological documentation of an invasive species, Sapium sebiferum (L.) Roxb

Phenological documentation and plant invasion are key contemporary issues in the biological sciences. Recognizing this, the present paper describes the phenological stages of an invasive species, Sapium sebiferum (L.) Roxb. A tree of the species was marked, and daily visits were made for recording its phenology. The Biologische Bundesanstalt, Bundessortenamt and CHemical industry (BBCH) scale was used for documenting the same. Of the total ten principal stages, eight were observed in the species. These stages started with bud development (stage 01) in the month of March and ended with leaf fall (stage 97) in the month of December. Descriptions of the phenological stages and their dates are provided in the text. It is hoped that such a phenological scale will be helpful in managing plant invasion.

Genes and oral cancer

Oral cancers have been one of the leading causes of deaths particularly in the developing countries. Prime reason for this high mortality and morbidity is attributed to the delay in diagnosis and prompt treatment. Relentless research in the field of oncology has led to the advent of novel procedures for the early detection of oral cancers. Molecular biology is highly promising in this regard. It is a procedure that detects alterations at a molecular level much before they are seen under a microscope and much before clinical changes occur. Molecular studies serve as the basis by which we will eventually be able not only to augment clinical assessment and classification of oral lesions but also predict malignant potential of oral lesions, thus reducing the incidence and increasing the scope for early diagnosis and treatment of oral cancers. However, making such sophisticated tools available for the common man in developing countries is one of the most important challenges faced today.

A simplified approach for placing the iris disc on a custom made ocular prosthesis: report of four cases

This case report describes a series of four cases of different age group, in which a simplified approach was applied for positioning the iris disc on a custom made ocular prosthesis. For each of the patient, a pre-fabricated eye was selected; whose iris and pupil closely matched that of the natural eye. This was duplicated for use as a tray in impression procedure. Iris portion of the stock eye was trimmed out and oriented on the cast according to previously transferred pupillary mark. This stock eye-wax pattern combination was tested in the eye socket, modified accordingly and finally cured in transparent heat cured acrylic resin. The technique to fabricate ocular prosthesis in present case reports modifies pre-fabricated eye prosthesis to a custom-made fit and aesthetics. This helped us to overcome the disadvantages of poor fit, inadequate movement and complex painting procedure and technique involved in making a custom-made ocular prosthesis. It can be concluded that close adaptation of the custom-made ocular prosthesis to the tissue bed provides maximum comfort and restores full physiologic function to the accessory organs of the eye.

Prosthetic guidelines for ocular rehabilitation in patients with phthisis bulbi: a treatment-based classification system

Prosthetic rehabilitation of phthisis bulbi defects is the only treatment option for cosmetic rehabilitation of patients with such defects. Currently, there is no treatment-based classification for prosthetic rehabilitation of patients with phthisis bulbi. Phthisical ocular defects and/or prosthetic rehabilitation were evaluated in an attempt to establish prosthetic guidelines that could be organized into a classification system. Fifty patients who received rehabilitation for phthisis bulbi were reviewed. Phthisis bulbi defects were divided into 4 classes. All the patients had rehabilitation, depending upon the class to which they were assigned. The aim of this treatment-oriented classification system was to organize and define the complex nature of the restorative decision-making process for patients with phthisis bulbi.

A multidisciplinary approach for ocular rehabilitation following surgical treatment of retinoblastoma: One year follow-up

Retinoblastoma is a highly malignant neoplasm. Most of the cases are usually advanced at the time of detection, requiring enucleation to salvage the child's life. Just treating the patient for cancer is not enough; the cosmetic rehabilitation of these patients is equally important and it should always be an integral part of their treatment, to help them re-integrate in the aesthetic conscious society. Rehabilitating such patients require a multidisciplinary approach involving the combined and timely efforts of an ophthalmologist, paediatric oncologist and a skilled maxillofacial prosthodontist. This paper presents a case of 3½-year-old girl who had enucleation of her right eye due to retinoblastoma along with chemotherapy and radiotherapy at the age of 3 years. The patient was recalled regularly for follow-up at 3 month intervals for ophthalmic examinations and she was rehabilitated cosmetically with customised ocular prosthesis during the various stages of her developmental growth.

Time resolved spectroscopy and gain studies of Fullerenes C60 and C70

The fluorescence decay time of Fullerenes C60 and C70 in pure form as well as in mixture with Coumarin C440 and Quinizarine dyes are studied. Results indicate that the decay of pure fullerenes is constant throughout the solute concentration and it is also independent of excitation wavelength, whereas in the case of mixture with dyes different behavior is noticed. We have also calculated the Stern-Volmer quenching constant and optical gain of both the fullerenes from which it is found that the optical gain is positive for Fullerene C70 only in a very narrow range of concentration.

Cephalometric evaluation of mandibular advancement at different horizontal jaw positions in obstructive sleep apnoea patients: a pilot study

BACKGROUND

The aim of this study was to comparatively evaluate the efficacy of the mandibular advancement device (MAD) at 50% (P2) and 75% (P3) of maximum mandibular advancement, relative to maximum intercuspation (P1) subjectively and objectively.

METHODS

Eighteen subjects previously diagnosed with obstructive sleep apnoea (OSA) were selected for the study. ESS score, VAS score, soft palate angle, MP-H distance, S-H distance, a C4 -H distance, a Pu -p Pu distance and total pharyngeal area were calculated at P1, P2 and P3 positions with the help of an adjustable MAD. The results were statistically analysed.

RESULTS

ESS score, VAS score, soft palate angle, MP-H distance, S-H distance and radius of curvature of airway at P2 and P3 were significantly lower compared to P1, but there was no significant difference between P2 and P3.

CONCLUSIONS

The MAD produced significant improvement in objective signs and subjective symptoms at both 50% and 75% of the maximum mandibular protrusion positions at comparable comfort levels. Therefore, MAD may be given at 50% of maximum advancement in order to reduce dental or temporomandibular joint disturbances.

Distribution of TMEM100 in the mouse and human gastrointestinal tract--a novel marker of enteric nerves

Identification of markers of enteric neurons has contributed substantially to our understanding of the development, normal physiology, and pathology of the gut. Previously identified markers of the enteric nervous system can be used to label all or most neuronal structures or for examining individual cells by labeling just the nucleus or cell body. Most of these markers are excellent but have some limitations. Transmembrane protein 100 (TMEM100) is a gene at locus 17q32 encoding a 134-amino acid protein with two hypothetical transmembrane domains. TMEM100 expression has not been reported in adult mammalian tissues but does appear in the ventral neural tube of embryonic mice and plays a role in signaling pathways associated with development of the enteric nervous system. We showed that TMEM100 messenger RNA is expressed in the gastrointestinal tract and demonstrated that TMEM100 is a membrane-associated protein. Furthermore TMEM100 immunoreactivity was restricted to enteric neurons and vascular tissue in the muscularis propria of all regions of the mouse and human gastrointestinal tract. TMEM100 immunoreactivity colocalized with labeling for the pan-neuronal marker protein gene product 9.5 (PGP9.5) but not with the glial marker S100ß or Kit, a marker of interstitial cells of Cajal. The signaling molecule, bone morphogenetic protein (BMP) 4, was also expressed in enteric neurons of the human colon and co-localized with TMEM100. TMEM100 is also expressed in neuronal cell bodies and fibers in the mouse brain and dorsal root ganglia. We conclude that TMEM100 is a novel, membrane-associated marker for enteric nerves and is as effective as PGP9.5 for identifying neuronal structures in the gastrointestinal tract. The expression of TMEM100 in the enteric nervous system may reflect a role in the development and differentiation of cells through a transforming growth factor β, BMP or related signaling pathway.

Lost salt technique for severely resorbed alveolar ridges: An innovative approach

The success of a complete denture relies on the principles of retention, stability and support. The prosthodontist skill lies in applying these principles efficiently in critical situations. Severely resorbed maxillary edentulous ridges that are narrow and constricted with increased inter ridge space provide decreased support, retention and stability. The consequent weight of the processed denture only compromises them further. This article describes a case report of an edentulous patient with resorbed ridges where a simplified technique of fabricating a hollow maxillary complete denture using lost salt technique was used for preservation of denture bearing areas. The hollowing of the denture reduces the weight of the denture, thereby enhancing stability and retention, reducing the further resorption of the jaws.

Application of artificial neural network, fuzzy logic and decision tree algorithms for modelling of streamflow at Kasol in India

The prediction of streamflow is required in many activities associated with the planning and operation of the components of a water resources system. Soft computing techniques have proven to be an efficient alternative to traditional methods for modelling qualitative and quantitative water resource variables such as streamflow, etc. The focus of this paper is to present the development of models using multiple linear regression (MLR), artificial neural network (ANN), fuzzy logic and decision tree algorithms such as M5 and REPTree for predicting the streamflow at Kasol located at the upstream of Bhakra reservoir in Sutlej basin in northern India. The input vector to the various models using different algorithms was derived considering statistical properties such as auto-correlation function, partial auto-correlation and cross-correlation function of the time series. It was found that REPtree model performed well compared to other soft computing techniques such as MLR, ANN, fuzzy logic, and M5P investigated in this study and the results of the REPTree model indicate that the entire range of streamflow values were simulated fairly well. The performance of the naïve persistence model was compared with other models and the requirement of the development of the naïve persistence model was also analysed by persistence index.

Technological options for the removal of arsenic with special reference to South East Asia

Arsenic contamination in ground water, used for drinking purpose, has been envisaged as a problem of global concern. However, arsenic contamination of ground water in parts of South East Asia is assuming greater proportions and posing a serious threat to the health of millions of people. A variety of treatment technologies based on oxidation, co-precipitation, adsorption, ion exchange and membrane process are available for the removal of arsenic from ground water. However, question remains regarding the efficiency and applicability/appropriateness of the technologies, particularly because of low influent arsenic concentration and differences in source water composition. Some of these methods are quite simple, but the disadvantage associated with them is that they produce large amounts of toxic sludge, which needs further treatment before disposal into the environment. Besides, the system must be economically viable and socially acceptable. In this paper an attempt has been made to review and update the recent advances made in the technological development in arsenic removal technologies to explore the potential of those advances to address the problem of arsenic contamination in South East Asia.

Computed tomographic evaluation of the effects of mandibular advancement devices on pharyngeal dimension changes in patients with obstructive sleep apnea

PURPOSE

The aims of this study were to evaluate the effect of a mandibular advancement device on oropharyngeal dimension in patients with obstructive sleep apnea (OSA) and reveal the predominate site of changes produced by mandibular advancement using computed tomography (CT).

MATERIALS AND METHODS

CT scans of 20 patients diagnosed with OSA were taken with and without the appliance. Three-dimensional changes in pharyngeal shape measured on cross-sectional CT images during two respiratory cycles after oral appliance insertion were estimated at five vertical levels using three variables: (1) lateral dimension, (2) anteroposterior dimension, and (3) cross-sectional area. Various parameters related to severity of OSA such as snoring volume, frequency, duration, and episodes; breathing pauses; oxygen saturation; Epworth Sleepiness Scale (ESS) score; and Apnea Hypopnea Index (AHI) score underwent comparative evaluation subjectively and objectively. Data were analyzed using the Student t test for parametric analysis.

RESULTS

A significant increase in the lateral and anteroposterior dimension of the pharyngeal lumen was observed at all five levels, but the mean change was greatest at the retroglossal level and smallest at the hypopharyngral level in both the lateral and anteroposterior dimensions. The cross-sectional area at all levels appeared to increase significantly, and apnea indices improved significantly. A significant decrease in snoring volume, snoring frequency, breathing pauses, snoring duration, snoring episodes, ESS score, and AHI score and a significant increase in oxygen saturation were found after treatment with the mandibular advancement device.

CONCLUSION

Within the limitations of this study, CT was shown to be useful in evaluating treatment efficacy in subjects with OSA.

Customization of stock eye prosthesis for a pediatric patient by a simplified technique

The unfortunate loss or absence of an eye may be caused by congenital defect , irreparable trauma, tumor or blind eye. The role of the maxillofacial prosthodontist in fabricating an ocular prosthesis to restore facial symmetry and normal appearance for the anophthalmic patient becomes essential. A custom-made ocular prosthesis is an excellent alternative for the people who lose their eye especially in young age. It has acceptable fit, retention and esthetics but is technically difficult to fabricate. On the other hand the stock eye has compromised fit and poor esthetics. Our case report presents a simple technique of customization of stock eye prosthesis to provide accurate fit and acceptable esthetics. How to cite this article: Jurel SK, Talwar N, Chand P, Singh RD, Gupta DS. Customization of Stock Eye Prosthesis for a Pediatric Patient by a Simplified Technique. Int J Clin Pediatr Dent 2012;5(2):155-158.

Split obturator: An innovative approach

A palatal prosthesis can improve function by closing the palatal defect, preventing regurgitation, and improving swallowing and speech. Although techniques have been previously described for fabrication of palatal obturator, but there has not been any technique to devise an obturator for a patient with palatal defect with a quadhelix orthodontic appliance overlying it. One cannot wait in such patients for completion of lengthy orthodontic treatment and then think of devising prosthesis as the patient cannot carry out normal functions like swallowing and speech without the closure of defect. This article focuses on an innovative method of fabricating a palatal obturator which aims at restoring the above-mentioned functions along with improving aesthetics. It also enables us to devise the fabrication of prosthesis in two parts for easy insertion and removal and as well as to be self-cleansable. Such prosthesis would markedly improve patient psychology and confidence.

A Noval Approach of Altered Cast Technique in Bilateral Partial Maxillectomy Patient with Severely Restricted Mouth Opening

Patients with extensive head and neck injuries due to trauma and/or extensive surgical procedures often exhibit a severely limited ability to open the mouth. For the dentist involved in prosthodontic treatment of such patients, restricted mouth opening commonly leads to compromised impressions and prostheses especially in cases where both hard and soft palatal parts have been resected. In prosthodontic treatment, the loaded impression tray is the largest item requiring intraoral placement. During impression procedures, wide mouth opening is required for proper tray insertion and alignment. This is not possible in patients with restricted mouth opening, so a modification of the standard impression procedure is often necessary to accomplish this fundamental step in the fabrication of a successful prosthesis. An alteration in the final impression procedure was made using altered cast technique for fabricating an obturator prosthesis with soft palate extension, and the result obtained was quite satisfactory.

Efficacy of casein phosphopeptide-amorphous calcium phosphate to prevent stain absorption on freshly bleached enamel: An in vitro study

BACKGROUND

Teeth when subjected to bleaching bring about the desiccation of the enamel, making it more susceptible to stain absorption. While subjecting the freshly bleached enamel surface to various surface treatments of Fluoride and Casein Phosphopeptide - Amorphous Calcium phosphate (CPP-ACP) brought about the reduction in stain absorption, which is assessed in this study.

AIMS

The study aims to evaluate the tea stain absorption on freshly bleached enamel surface of extracted human teeth with varied surface treatment. The stain absorption was evaluated at the end of one hour and 24 hours post bleaching.

MATERIALS AND METHODS

Forty extracted human permanent maxillary central incisors were subjected to bleaching with 10% carbamide peroxide for eight days. They were divided into four groups of 10 each. Group I was control group. Group II was immersed in tea solution without surface treatment, while Group III and IV were immersed in tea solution with surface treatment of topical Fluoride and CPP-ACP respectively. Spectrophotometer was used for color analysis.

RESULTS

Surface treatment with CPP-ACP and topical fluoride on freshly beached enamel surface, significantly reduced the stain absorption.

CONCLUSION

Remineralizing agents reduce stain absorption after tooth bleaching.

Canine tip marker: a simplified tool for measuring intercanine distance

PURPOSE

Appropriate selection of anterior teeth is considered to be of paramount importance in the success of denture prostheses. This study was undertaken to evaluate the correlation between the intercanthal width and interalar width with intercanine distance, in North Indian male and female patients for predicting the mesiodistal width of the maxillary anterior teeth during tooth selection.

MATERIALS AND METHODS

The study was conducted with 100 North Indian patients (50 men, 50 women) ranging in age from 17 to 21 years. A digital caliper with an accuracy of 0.01 mm was used to measure the intercanthal and interalar width. A T-shaped flat metal plate (canine tip marker) was used to mark the intercanine distance, which was then measured with the digital caliper. These measurements were interpreted and subjected to statistical analysis. Student's t-test was applied to test the correlation between intercanthal width and interalar width with intercanine distance.

RESULTS

Calculated t-values between intercanine distances with interalar width in both male and female groups were 3.14 and 3.56, respectively, greater than the standard value taken at a 5% level of significance with 48 degree of freedom, showing a higher correlation of interalar width with the intercanine distance. Values obtained between intercanthal width and intercanine distance were lower than the standard value in both groups.

CONCLUSIONS

A significant correlation was found between interalar width and intercanine distance in both men and women, suggesting that interalar width can be used as a reliable guide for maxillary anterior teeth selection.

Förster's resonance energy transfer between Fullerene C60 and Coumarin C440

The interaction between Coumarin C440 with Fullerene C60 has been studied by fluorescence and time resolved spectroscopic techniques. The Coumarin C440-Fullerene C60 pair shows Forster's resonance energy transfer (FRET) from Coumarin C440 (donor) to Fullerenes C60 (acceptor). The FRET efficiency of this pair increases with the increase of the acceptor concentration. The critical energy transfer distance (R0) at which transfer efficiency is 50% is found to be 34Ǻ. Stern-Volmer plot indicates static as well as dynamic quenching. However, the FRET studies show highest efficiency at the critical stage of dimer formation.

Concentration-dependent energy transfer studies in ternary dye mixture of Stilbene-420, Coumarin-540 and Nile Blue

The energy transfer studies in the case of ternary dye mixture [Stilbene-420 (donor)+Coumarin-540 (intermediator)+Nile Blue (acceptor)] have been done and discussed through optical gain characteristics at various acceptor concentrations under nitrogen laser excitation. The concentration of the other two dyes were kept constant. It is observed that the concentration of the acceptor dye plays a very critical role in energy transfer dye laser (ETDL) as small change in its concentration varies the intensity of the laser output in the red region by large amount. Also, the highest laser output in the red region is obtained when the concentration of the acceptor dye is slightly higher than that of the intermediator dye. The present studies are helpful in deciding the optimum concentration of the acceptor dye to be used in ternary dye mixture for maximum gain and tuning range. The ternary dye mixture under study provides an ETDL tuning range up to 700 nm.

Bilateral ptosis following wasp sting

We report a case of bilateral ptosis due to wasp sting which was completely treatable.

Anaerobiosis induced virulence of Salmonella typhi

BACKGROUND & OBJECTIVES

Anaerobic conditions are frequently encountered by pathogens invading the gastrointestinal tract due to low/limiting oxygen conditions prevalent in the small intestine. This anaerobic stress has been suggested to enhance the virulence of gut pathogens. In the present study, we examined the effect of anaerobiosis on the virulence of Salmonella Typhi, a Gram negative bacteria which invades through the gut mucosa and is responsible for typhoid fever.

METHODS

Salmonella Typhi (ty2) was cultured in aerobic and anaerobic conditions to compare its virulence by rabbit ileal loop assay, hydrophobicity assay, expression of outer membrane proteins (OMPs) and antioxidant enzymes assay.

RESULTS

Anaerobically grown S. Typhi showed significantly higher cell surface hydrophobicity as compared to aerobic bacteria. In vivo toxin production by rabbit ileal loop assay also showed significantly higher fluid accumulation with anaerobic S. Typhi. Expression of OMPs in anaerobic S. Typhi showed a distinct induction of five outer membrane proteins. We observed that exposure of anaerobic S. Typhi to aerobic conditions induced significantly higher level of antioxidant enzymes like superoxide dismutase (SOD) and catalase.

INTERPRETATION & CONCLUSION

Our results suggest that exposure of S. Typhi to anaerobic conditions enhances its virulence.

Clathrin-dependent and -independent internalization of plasma membrane sphingolipids initiates two Golgi targeting pathways

Sphingolipids (SLs) are plasma membrane constituents in eukaryotic cells which play important roles in a wide variety of cellular functions. However, little is known about the mechanisms of their internalization from the plasma membrane or subsequent intracellular targeting. We have begun to study these issues in human skin fibroblasts using fluorescent SL analogues. Using selective endocytic inhibitors and dominant negative constructs of dynamin and epidermal growth factor receptor pathway substrate clone 15, we found that analogues of lactosylceramide and globoside were internalized almost exclusively by a clathrin-independent ("caveolar-like") mechanism, whereas an analogue of sphingomyelin was taken up approximately equally by clathrin-dependent and -independent pathways. We also showed that the Golgi targeting of SL analogues internalized via the caveolar-like pathway was selectively perturbed by elevated intracellular cholesterol, demonstrating the existence of two discrete Golgi targeting pathways. Studies using SL-binding toxins internalized via clathrin-dependent or -independent mechanisms confirmed that endogenous SLs follow the same two pathways. These findings (a) provide a direct demonstration of differential SLs sorting into early endosomes in living cells, (b) provide a "vital marker" for endosomes derived from caveolar-like endocytosis, and (c) identify two independent pathways for lipid transport from the plasma membrane to the Golgi apparatus in human skin fibroblasts.

Role of anaerobiosis in virulence of Salmonella typhimurium

Intestinal pathogens are exposed to various stress conditions during their infectious cycle. Anaerobiosis, one of such hostile condition, is offered by the host within gut and intestinal lumen, where survival, multiplication and entry into intestinal epithelial cells is priority for the invading pathogen. In the present study, a virulent strain of S. typhimurium (1402/84) was grown under anaerobic conditions and its virulence characteristics such as host cell binding, penetration and intracellular survival were compared with aerobic S. typhimurium. Anaerobically grown S. typhimurium showed significantly higher binding to immobilized mice enterocytes and intestinal mucus as compared to bacteria grown aerobically. Anaerobic bacteria also showed an early penetration of mucus and subsequent binding to underlying immobilized enterocytes, in vitro. Anaerobic S. typhimurium exhibited increased intracellular survival within spleen macrophages of mice and caused significantly higher fluid accumulation in ligated rabbit ileal loops as compared to aerobic bacteria. LD50 of anaerobic S. typhimurium was also observed to be 2 fold lower when compared to aerobic bacteria. Cell surface hydrophobicity of anaerobic S. typhimurium was also found to be significantly higher than aerobic bacteria. Thus, it appears that exposure of S. typhimurium to anaerobiosis results in its enhanced virulence, adhesion and penetration of host cells.

Anaemia and mental functions in rural primary school children

Mental functions of 388 (6-8 years of age) rural primary school children matched for social and educational status were assessed in relation to anaemia and nutritional status. Malin's intelligence scale for Indian children and an arithmetic test were administered to assess intelligence, attention and concentration. No significant differences were found between the IQ scores of anaemic and non-anaemic groups, except for the subtest digit span. In contrast, there was an effect of nutritional status on IQ scores. Observations on the arithmetic test showed that anaemia is associated with lower levels of attention and concentration.

Radioimmunoassay of some hormones simultaneously measured in serum and breast cyst fluid

Blood and breast cyst fluid were drawn simultaneously for hormonal determination. There was no difference between serum and cyst fluid values of PRL and TSH. A significant difference was noted for LH (p less than 0.01) and FSH (p less than 0.05), serum concentrations being higher than cyst fluid concentrations.

Guanine aminohydrolase in rat and mouse red cells: a potent inhibitor of guanylation of tRNA

1. The red blood cells of mice and rats contained guanine aminohydrolase (EC 3.5.4.3). This enzyme was not present in rabbit, sheep or human red blood cells. 2. The enzyme from rat blood cells was separated into two activities by column chromatography on DEAE-cellulose. Both isozymes were labile but it was possible to show that the more abundant enzyme followed Michaelis-Menten kinetics, had an apparent Km of 4.0-10-6 M and was not activated by GTP nor inhibited by allantoin. 3. We believe, therefore, that guanine aminohydrolase was the protein in rat and mouse red blood cells that inhibited the enzyme (in rabbit reticulocytes) responsible for guanylation of tRNA.