Assessment of in vitro skin irritation potential of nanoparticles: RHE model.

The skin irritation test is designed for the prediction of acute skin irritation of nanoparticles by measurement of its cytotoxic effect, as reflected in the MTT assay, on the Reconstructed Human Epidermis (RHE) model. RHE tissues are commercially available.

Repeated dose dermal toxicity study of nano zinc oxide with Sprague-Dawley rats.

CONTEXT: In light of the increased use of zinc oxide nanoparticles in cosumer products such as sunscreens, there is a need for screening the potential dermal toxicity of these nanoparticles. OBJECTIVE: The aim of this study is to identify the risk associated with the nano zinc oxide at realistic exposure levels through dermal route. This study is to understand the toxic potential of nano zinc oxide through repeated dermal exposure for a period of 28 days. MATERIALS AND METHODS: Six- to 8-week-old Sprague-Dawley rats were applied with three different doses (75, 180, and 360 mg/kg body weight) of nano zinc oxide (20 nm) at 5 days/week basis for a period of 28 days. The dose levels were calculated taking into consideration the percentage of nanomaterial in the sunscreen, number of application times, and average weight of the consumer in order to assess the realistic risk related to it. Control group animals were applied with distilled water alone. The collagen content was estimated in skin and tail of all the treated and control animals. RESULTS: The content was significantly decreased in all the nano zinc oxide-treated groups with an inverse dose relationship. DISCUSSION AND CONCLUSION: The percentage collagen loss was high in skin when compared with tail. This may be due to the site of application where in the nano zinc oxide may be passed through skin due to their small size and may induce oxidative stress. Hence, we suggest that regulators and industry need to address the toxicity of nanomaterials with a realistic exposure assessment rather following conventional dose measurements following existing protocols.

A Cross Sectional Study on the Relationship Between the Body Mass Index (BMI) and the Audiovisual Reaction Time (ART).

INTRODUCTION: The reaction time is the time interval between the stimulus application and the proper response. The neurophysiological studies suggest a relationship of the BMI with the cognition, attention and the memory. AIM: To study the relationship between the Body Mass Index (BMI) and the audiovisual reaction time in young healthy females. MATERIALS AND METHODS: This study was carried out in the Department of Physiology on 90 young, healthy females who were in the Ist year MBBS and BDS at GMC and GDC Aurangabad. The height and weight were recorded and the BMI was calculated. The subjects were divided into 3 groups: those with normal weight, underweight and overweight according to the WHO criteria. The simple reaction time was measured with the help of Audio Visual Reaction Time Apparatus in all the three groups. The data was analyzed by the one way ANOVA test by using the Graphpad Prism Software. RESULT: There was a prolongation of both ART and VRT in the underweight and the overweight individuals. When the VRT was compared, it was found to be statistically significant. CONCLUSION: Our study showed that the BMI of an individual affected the audio visual reaction time, which was an indirect measure of the sensory motor association.

Assessment of the dermal and ocular irritation potential of multi-walled carbon nanotubes by using in vitro and in vivo methods.

In view of increase in the manufacture of various nanomaterials runs the risk of increased human exposure, in vitro screening will serve as a preliminary method to assess possible risk in animal studies. We attempted to know whether the validated in vitro alternative models established for chemicals, drugs, pesticides are suitable for nanomaterials, since these materials differ largely and may interfere with commonly used test systems. In vitro and in vivo studies on ocular and dermal irritation were carried out with two different sizes of multi-walled carbon nanotubes (MWCNT). The results of acute eye irritation toxicity studies with two different sizes of MWCNT in rabbits demonstrated reversible conjunctival redness and discharge and exhibited minimal concern while acute dermal irritation studies indicated that MWCNT of two sizes were non-irritant to the skin of rabbits. Both the sizes of MWCNT revealed non-irritant result in HE-CAM test. In vitro skin (EPISKIN) irritation studies revealed that two sizes of MWCNT are non-irritant to skin. In conclusion this work purports, the future of alternative research lies in the validation of the methodology for nanomaterials.

Hen egg chorioallantoic membrane bioassay: an in vitro alternative to draize eye irritation test for pesticide screening.

As an alternative to the standard Draize eye irritation test, the potential irritancy of compounds was evaluated by observing adverse changes that occur in chorioallantoic membrane CAM) of the hen egg (HECAM) after exposure to a test chemical placed directly on the CAM. The occurrence of hemorrhage, coagulation, and lysis in response to a test compound is the basis for employing this technique to evaluate its potential for in vivo damage to mucous membrane, in particular the eye. Irritancy is scored according to the severity and speed at which damage occurs. In the present study, five different classes of pesticides were screened for irritation potential. There was good correlation between the HECAM assay and the in vivo Draize eye irritation test. The proposed HECAM assay, which reduces the requirement for laboratory animals, could be a painless alternative to the Draize test.

Florid cemento-osseous dysplasia: Review and report of two cases.

Only three Indian patients of florid cemento-osseous dysplasia have been reported (less than 2%), according to the review of recent literature (2003). This makes the occurrence of FCOD a relatively rare phenomenon. The age group may vary from 19-76 years and typically presents in the fourth and fifth decade. In most of the cases, patients do not have family history of the disease. We report two cases showing classic radiologic features. The diagnosis of our cases were made radiographically.