Knowledge and practice regarding safety standards of oral radiology among dental practitioners in western Maharashtra,India

Objective

To evaluate the knowledge and practice regarding safety standards of oral radiology among dental practitioners in Mumbai, India.

Methods

A cross-sectional study was conducted among 200 dental practitioners. Data related to methods of radiation protection were collected by a predesigned, pretested, self-administered questionnaire. The data were analyzed and the results expressed in percentages.

Results

The bisecting angle technique was preferred by 69.2 % of the practitioners. Most of the X-ray machines had a pointed cone (60.6 %) type of position-indicating device. Both conventional films and digital sensors were used as image receptors with slight preference for the latter (44.8 vs. 55.1 %, respectively). Approximately three-fourths of the dental practitioners (75.4 %) used E-speed films, and in 48.0 % of cases, either dentists or assistants held the X-ray film with their fingers while taking radiographs. Most of the practitioners used a lead apron for patient protection either regularly (23.6 %) or occasionally (48.0 %). A total of 40.9 % of the dentists stood near the patient without wearing a lead apron during exposure. Only 14.7 % were aware of the position-and-distance rule, which is used when no protective barrier is present. Nearly half of the dentists changed the exposure time according to the patient and region to be radiographed.

Conclusion

The results of this study indicate that more work must be done to increase the knowledge of radiation protection among practicing dentists.

     

A critical review of pharmacological significance of Hydrogen Sulfide in hypertension

In the family of gas transmitters, hydrogen sulfide (H₂S) is yet not adequately researched. Known for its rotten egg smell and adverse effects on the brain, lungs, and kidneys for more than 300 years, the vasorelaxant effects of H₂S on blood vessel was first observed in 1997. Since then, research continued to explore the possible therapeutic effects of H₂S in hypertension, inflammation, pancreatitis, different types of shock, diabetes, and heart failure. However, a considerable amount of efforts are yet needed to elucidate the mechanisms involved in the therapeutic effects of H₂S, such as nitric oxide-dependent or independent vasodilation in hypertension and regression of left ventricular hypertrophy. More than a decade of good repute among researchers, H₂S research has certain results that need to be clarified or reevaluated. H₂S produces its response by multiple modes of action, such as opening the ATP-sensitive potassium channel, angiotensin-converting enzyme inhibition, and calcium channel blockade. H₂S is endogenously produced from two sulfur-containing amino acids L-cysteine and L-methionine by the two enzymes cystathionine γ lyase and cystathionine β synthase. Recently, the third enzyme, 3-mercaptopyruvate sulfur transferase, along with cysteine aminotransferase, which is similar to aspartate aminotransferase, has been found to produce H₂S in the brain. The H₂S has interested researchers, and a great deal of information is being generated every year. This review aims to provide an update on the developments in the research of H₂S in hypertension amid the ambiguity in defining the exact role of H₂S in hypertension because of insufficient number of research results on this area. This critical review on the role of H₂S in hypertension will clarify the gray areas and highlight its future prospects.KEY WORDS: 3-3-mercaptopyruvate sulfur transferase, cystathionine γ lyase, cystathionine β synthase, cysteine aminotransferase, hydrogen sulfide, hypertension     

RNAi-mediated immunity provides strong protection against the negative-strand RNA vesicular stomatitis virus in Drosophila

Activation of innate antiviral responses in multicellular organisms relies on the recognition of structural differences between viral and cellular RNAs. Double-stranded (ds)RNA, produced during viral replication, is a well-known activator of antiviral defenses and triggers interferon production in vertebrates and RNAi in invertebrates and plants. Previous work in mammalian cells indicates that negative-strand RNA viruses do not appear to generate dsRNA, and that activation of innate immunity is triggered by the recognition of the uncapped 5' ends of viral RNA. This finding raises the question whether antiviral RNAi, which is triggered by the presence of dsRNA in insects, represents an effective host-defense mechanism against negative-strand RNA viruses. Here, we show that the negative-strand RNA virus vesicular stomatitis virus (VSV) does not produce easily detectable amounts of dsRNA in Drosophila cells. Nevertheless, RNAi represents a potent response to VSV infection, as illustrated by the high susceptibility of RNAi-defective mutant flies to this virus. VSV-derived small RNAs produced in infected cells or flies uniformly cover the viral genome, and equally map the genome and antigenome RNAs, indicating that they derive from dsRNA. Our findings reveal that RNAi is not restricted to the defense against positive-strand or dsRNA viruses but can also be highly efficient against a negative-strand RNA virus. This result is of particular interest in view of the frequent transmission of medically relevant negative-strand RNA viruses to humans by insect vectors.