Effect of ocular magnification on macular measurements made using spectral domain optical coherence tomography

Aim:

The aim of the present study was to study the effect of ocular magnification on macular measurements made using spectral domain optical coherence tomography (OCT).

Materials and Methods:

One hundred and fifty-one subjects were included from the normative study of foveal morphology carried out at our hospital. Subjects underwent comprehensive eye examination and macular scanning using Cirrus high-definition OCT and axial length (AXL) measurement. Macular cube 512 × 128 scan protocol was used for scanning the macula. Automated measurements of the fovea namely foveal diameter, foveal slope (lateral measurements) and foveal depth (axial measurement) were taken. A correction factor for ocular magnification was done using the formula t = p × q × s, where “t” is the corrected measurement, “p” is the magnification of OCT, “q” is the ocular magnification, and “s” is the measurement on OCT without correction. The difference between corrected and uncorrected measurements was evaluated for statistical significance.

Results:

Mean AXL was 22.95 ± 0.78 mm. Refractive error ranged from −3D to +4D. Mean difference between measured and corrected foveal diameter, slope and depth was 166.05 ± 95.37 µm (P < 0.001), 0.81° ± 0.53° (P < 0.001) and 0.05 ± 0.49 µm (P = 0.178) respectively. AXL lesser than the OCT calibrated value of 24.46 mm showed an increased foveal diameter (r = 0.961, P < 0.001) and a reduced foveal slope (r = −0.863, P < 0.001) than the corrected value.

Conclusion:

Lateral measurements made on OCT varied with AXL s other than the OCT calibrated value of 24.46 mm. Therefore, to estimate the actual dimensions of a retinal lesion using OCT, especially lateral dimensions, we recommend correction for the ocular magnification factor.     

A Comparative Evaluation of the Vertical Root Fracture Resistance of Endodontically Treated Teeth using Different Root Canal Sealers: An in vitro Study

Objective: The objective of this study is to evaluate the vertical root fracture resistance of endodontically treated teeth obturated with - Tubli-Seal EWT/Gutta-percha, AH Plus/Gutta-percha, Epiphany SE sealer/Epiphany point. Study design: Sixty-five single rooted premolars were decoronated and root length was 14 mm for each specimen. Fifty five teeth were enlarged up to ISO size 40 master apical file with stainless steel K-files using standardized preparation and remaining ten teeth were served as negative control. Then teeth were randomly assigned into different groups depending on sealer used for obturation as follows: Group 1: Negative control-no instrumentation was performed. Group 2: Positive control-gutta-percha with out the use of any sealer. Group 3: Experimental group-gutta-percha and Tubli-Seal EWT root canal sealer. Group 4: Experimental group-gutta-percha and AH Plus. Group 5: Experimental group-epiphany SE sealer and epiphany points. After 72 hours, the specimens were embedded in autopolymerizing resin leaving 7 mm of each root exposed and were subjected to fracture testing under universal testing machine at a crosshead speed of 1.0 mm per minute until the root fractured. Results were statistically analyzed using one-way ANOVA and independent t-test. Results: Showed that Epiphany SE sealer/Epiphany points showed highest mean fracture resistance and Tubli-Seal EWT group showed the least fracture resistance of all the materials tested. There was no statistically significant difference among experimental groups. Conclusion: Epiphany SE sealer/Epiphany points demonstrated highest fracture resistance values than the other materials tested and intact tooth had highest resistance against vertical root fracture. Clinical significance: Epiphany SE sealer/Epiphany points may be one of the materials of choice in the endodontic treatment of teeth. Keywords: Epiphany sealer/Epiphany points, AH Plus/Guttapercha, Tubli-Seal EWT, Vertical root fracture. How to cite this article: Nagpal A, Annapoorna BM, Prashanth MB, Prashanth NT, Singla M, Deepak BS, Singh A, Tavane PN. A Comparative Evaluation of the Vertical Root Fracture Resistance of Endodontically Treated Teeth using Different Root Canal Sealers: An in vitro Study. J Contemp Dent Pract 2012;13(3):351-355. Source of support: Nil Conflict of interest: None declared.     

Associations Between Complex PCI and Prasugrel or Clopidogrel Use in Patients With Acute Coronary Syndrome Who Undergo PCI: From the PROMETHEUS Study

Background

Potent P2Y₁₂ inhibitors might offer enhanced benefit against thrombotic events in complex percutaneous coronary intervention (PCI). We examined prasugrel use and outcomes according to PCI complexity, as well as analyzing treatment effects according to thienopyridine type.

Adenovirus replication-competent vectors (KD1, KD3) complement the cytotoxicity and transgene expression from replication-defective vectors (Ad-GFP,Ad-Luc)

The successful clinical application of adenovirus (Ad) in cancer control has been of limited success because of the current inability to infect the majority of cancer cells with a large amount of vector. In this study, we show that when human lung tumors growing in immunodeficient nude mice were coinfected with a replication-defective (RD) Ad vector expressing green fluorescent protein and a replication-competent (RC) Ad vector named KD3, KD3 enhanced the expression of green fluorescent protein throughout the tumor. Also, KD3 and another RC vector named KD1 complemented the expression of luciferase from a RD vector in a human liver tumor xenotransplant in nude mice. Altogether, these results suggest that the combination of a RD vector with a RC vector might be a more effective treatment for cancer than either vector alone due to more widespread dissemination of the virus.     

Fetal Blood Sampling and Its Complications Related to the Indications for Fetal Blood Sampling

Summary: A prospective study on fetal blood sampling (FBS) was conducted in the Fetomaternal Medicine Division of the Department of Obstetrics and Gynaecology at the National University Hospital, Singapore. FBS was performed on 159 occasions in 156 women between January, 1988 and December, 1991. The aim of this study was to identify the factors that were associated with an adverse outcome following the procedure.
Twenty four abnormal pregnancies were terminated; of the remaining 132 desired pregnancies the overall pregnancy loss was 44 (33.3%), which included those within 2 weeks and those after 2 weeks of the procedure and neonatal deaths. Fetal loss occurring within 2 weeks of the procedure is considered a procedure-related loss which occurred in 19 (14.3%) of the 132 pregnancies. When the fetal loss occurred within 2 weeks of the procedure 89% had a major abnormality on ultrasonographic scanning.
The conclusion from our study is that the risks of FBS were increased in abnormal pregnancies, most likely due to the underlying pathology.