Three-dimensional micro-structurally informed in silico myocardium-Towards virtual imaging trials in cardiac diffusion weighted MRI

In silico tissue models (viz. numerical phantoms) provide a mechanism for evaluating quantitative models of magnetic resonance imaging. This includes the validation and sensitivity analysis of imaging biomarkers and tissue microstructure parameters. This study proposes a novel method to generate a realistic numerical phantom of myocardial microstructure. The proposed method extends previous studies by accounting for the variability of the cardiomyocyte shape, water exchange between the cardiomyocytes (intercalated discs), disorder class of myocardial microstructure, and four sheetlet orientations. In the first stage of the method, cardiomyocytes and sheetlets are generated by considering the shape variability and intercalated discs in cardiomyocyte-cardiomyocyte connections. Sheetlets are then aggregated and oriented in the directions of interest. The morphometric study demonstrates no significant difference (p>0.01) between the distribution of volume, length, and primary and secondary axes of the numerical and real (literature) cardiomyocyte data. Moreover, structural correlation analysis validates that the in-silico tissue is in the same class of disorderliness as the real tissue. Additionally, the absolute angle differences between the simulated helical angle (HA) and input HA (reference value) of the cardiomyocytes (4.3°±3.1°) demonstrate a good agreement with the absolute angle difference between the measured HA using experimental cardiac diffusion tensor imaging (cDTI) and histology (reference value) reported by (Holmes et al., 2000) (3.7°±6.4°) and (Scollan et al. 1998) (4.9°±14.6°). Furthermore, the angular distance between eigenvectors and sheetlet angles of the input and simulated cDTI is much smaller than those between measured angles using structural tensor imaging (as a gold standard) and experimental cDTI. Combined with the qualitative results, these results confirm that the proposed method can generate richer numerical phantoms for the myocardium than previous studies.

Reconstruction of Connected Digital Lines Based on Constrained Regularization

This paper presents a new approach for reconstruction of disconnected digital lines (DDLs) based on a constrained regularization model which ensures connectivity of the digital lines (DLs) in the discrete image plane. The first step in this approach is to determine the order of given pixels of the DDL. To determine connectivity of pixels, we use the usual 8-neighbor connectivity in discrete images. For any neighboring pixels of the DDL that are not connected, we determine a number of new pixel values that need to be reconstructed between these pixels. Next, the integer-valued x - and y -coordinates of the location of the pixels of the DDLs are segregated into two 1D signal vectors. Then the x - and y -coordinates of the missing pixels of the DDLs are estimated using a new constrained regularization. While the solution of this constrained minimization problem provides real values for the x - and y -coordinates of pixels positions, the imposed constraint ensures connectivity of the resulting DLs in the image plane after transforming the computed values from [Formula: see text] to [Formula: see text]. The proposed regularization approach forces connected lines with small curvature. The experimental results demonstrate that the proposed technique improves DL intersection detection, as well. Moreover, this technique has a high potential to be used as a fast approach in binary image inpainting particularly overcoming the shortcomings of conventional methods which cause destruction of thin objects and blurring in the recovered regions.

Missing Surface Estimation Based on Modified Tikhonov Regularization: Application for Destructed Dental Tissue

Estimation of missing digital information is mostly addressed by one or two-dimensional signal processing methods; however, this problem can emerge in multi-dimensional data including 3D images. Examples of 3D images dealing with missing edge information are often found using dental micro-CT, where the natural contours of dental enamel and dentine are partially dissolved or lost by caries. In this paper, we present a novel sequential approach to estimate the missing surface of an object. First, an initial correct contour is determined interactively or automatically, for the starting slice. This contour information defines the local search area and provides the overall estimation pattern for the edge candidates in the next slice. The search for edge candidates in the next slice is performed in the perpendicular direction to the obtained initial edge in order to find and label the corrupted edge candidates. Subsequently, the location information of both initial and nominated edge candidates are transformed and segregated into two independent signals (X-coordinates and Y-coordinates) and the problem is changed into error concealment. In the next step, the missing samples of these signals are estimated using a modified Tikhonov regularization model with two new terms. One term contributes in the denoising of the corrupted signal by defining an estimation model for a group of mildly destructed samples, and the other term contributes in the estimation of the missing samples with the highest similarity to the samples of the obtained signals from the previous slice. Finally, the reconstructed signals are transformed inversely to edge pixel representation. The estimated edges in each slice are considered as initial edge information for the next slice and this procedure is repeated slice by slice until the entire contour of the destructed surface is estimated. The visual results as well as quantitative results (using both contour-based and area-based metrics) for seven image datasets of tooth samples with considerable destruction of the dentin-enamel junction (DEJ) demonstrates that the proposed method can accurately interpolate the shape and the position of the missing surfaces in computed tomography images in both two and three dimensions (e.g. 14.87 ±3.87 μ m of mean distance (MD) error for the proposed method versus 7.33 ±0.27 μm of MD error between human experts and 1.25 ±~0 % error rate (ER) of the proposed method versus 0.64 ±~0 % of ER between human experts (~1% difference)).

A comparative study of new and current methods for dental micro-CT image denoising

OBJECTIVES

The aim of the current study was to evaluate the application of two advanced noise-reduction algorithms for dental micro-CT images and to implement a comparative analysis of the performance of new and current denoising algorithms.

METHODS

Denoising was performed using gaussian and median filters as the current filtering approaches and the block-matching and three-dimensional (BM3D) method and total variation method as the proposed new filtering techniques. The performance of the denoising methods was evaluated quantitatively using contrast-to-noise ratio (CNR), edge preserving index (EPI) and blurring indexes, as well as qualitatively using the double-stimulus continuous quality scale procedure.

RESULTS

The BM3D method had the best performance with regard to preservation of fine textural features (CNREdge), non-blurring of the whole image (blurring index), the clinical visual score in images with very fine features and the overall visual score for all types of images. On the other hand, the total variation method provided the best results with regard to smoothing of images in texture-free areas (CNRTex-free) and in preserving the edges and borders of image features (EPI).

CONCLUSIONS

The BM3D method is the most reliable technique for denoising dental micro-CT images with very fine textural details, such as shallow enamel lesions, in which the preservation of the texture and fine features is of the greatest importance. On the other hand, the total variation method is the technique of choice for denoising images without very fine textural details in which the clinician or researcher is interested mainly in anatomical features and structural measurements.

Prevention of selenite-induced cataractogenesis by Origanum vulgare extract

The present study sought to assess antioxidant effect of Origanum vulgare extract in preventing selenite-induced cataractogenesis. This study was performed on Young white rats received sodium selenite (30 nmol g(-1) birth weight) subcutaneously on day 13 post partum during two months in 2009. Cataract formation and intensity was detected and measured by slit-lamp. Origanum vulgare (Ov) extract (2 g kg(-1)) was given (1-2 times) intraperitoneal at different times with respect to the selenite administration lens opacification was analyzed in selenite, selenite-Ov, Ov and control groups on day 7 after selenite administration. Ov extract have revealed a significant protective effect against selenite induced cataract when injected 1 and 2 day (2 times) before selenite injection. There is a protective effect of Ov against selenite induced cataract formation. It is supposed that the anticataract effect of Ov extract could be based on direct or indirect antioxidant mechanisms.

A comparison of cold knife, CO2 laser, and electrosurgical loop conization in the treatment of cervical intraepithelial neoplasia

Thirty patients with histologically confirmed high-grade squamous intraepithelial lesions (SIL) were treated by either cold knife, laser, or electrosurgical loop conization, all of which were performed under general anesthesia. The three methods were compared with respect to the immediate surgical complications, ease of performance, delayed complications, and quality of histologic specimens. The electrosurgical loop conization had decreased blood loss and reduced operative time and proved to be tissue sparing. There were no significant differences in the three groups in the persistence rates of cervical intraepithelial neoplasia (CN) after treatment. Histologic analysis revealed comparable coagulation artifact in the laser and electrosurgical loop groups that the cold knife group did not have. The endocervical component of the electrocautery showed extensive denudation and coagulation artifact that made recognition of CIN extremely difficult. We conclude that the electrocautery should be used only as an excisional method of the transformation zone for lesions well defined on the ectocervix, since it is unreliable if the lesion extends into the endocervix.

Leiomyomatosis peritonealis disseminata. A report of two cases

Leiomyomatosis peritonealis disseminata (LPD), also known as diffuse peritoneal leiomyomatosis, is characterized by the presence of multiple, small nodules scattered over the abdominopelvic viscera and peritoneum. These nodules are composed of benign smooth muscle cells. As shown in this report of two cases, the disorder occurs mostly in women of reproductive age and rarely in postmenopausal ones. LPD is a benign condition for which conservative management is indicated.

Primary biliary carcinoma with metastasis to the ovary

The ovary is a relatively frequent site of metastasis from malignant neoplasia arising elsewhere in the body, the majority of these originating from the GI tract. The best known tumor of this type is signet-ring cell adenocarcinoma (Krukenberg tumor) of gastric origin. The gall bladder and bile ducts are rare sources of these metastases. Asymptomatic carcinoma of the cystic duct metastasizing to the ovary is extremely rare. We are reporting such a case in which the patient presented with no GI or hepatic symptoms. The cystic duct carcinoma was an incidental finding from routine and careful examination of the abdominal viscera.

Trans-activation of the JC virus late promoter by the tat protein of type 1 human immunodeficiency virus in glial cells

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC virus (JCV), a human papovavirus. PML is a relatively rare disease seen predominantly in immunocompromised individuals and is a frequent complication observed in AIDS patients. The significantly higher incidence of PML in AIDS patients than in other immunosuppressive disorders has suggested that the presence of human immunodeficiency virus type 1 (HIV-1) in the brain may directly or indirectly contribute to the pathogenesis of this disease. In the present study we have examined the expression of the JCV genome in both glial and non-glial cells in the presence of HIV-1 regulatory proteins. We find that the HIV-1-encoded trans-regulatory protein tat increases the basal activity of the JCV late promoter, JCVL, in glial cells. In a reciprocal experiment, the JCV early protein, the large tumor antigen, stimulates expression from JCVL and HIV-1 long terminal repeat promoter in both glial and non-glial cells. This trans-activation occurs at the level of RNA synthesis, as measured by the rate of transcription, stability of the message, and translation. We conclude that the presence of the HIV-1-encoded tat protein may positively affect the JCV lytic cycle in glial cells by stimulating JCV gene expression. Our results suggest a mechanism for the relatively high incidence of PML in AIDS patients than in other immunosuppressive disorders. Furthermore, our findings indicate that the HIV-1 regulatory protein tat may stimulate other viral and perhaps cellular promoters, in addition to its own.

Cell type-specific expression of JC virus early promoter is determined by positive and negative regulation

We analyzed control sequences of the human papovavirus JC virus (JCV) to define the cis-acting elements that regulate specific expression of the viral early region genes in glial cells. Nuclear run-on transcription, S1 analysis, and chloramphenicol acetyltransferase enzyme activity in a transient transfection assay established that the cell type-specific expression of JCV early genes is determined at the transcriptional level. Using DNase footprinting analysis of nuclear proteins prepared from glial and nonglial cells, we located four regions within the JCV control sequences that specifically interacted with the proteins. In glial cells, all four domains contributed to the specific expression of a heterologous promoter, whereas in nonglial cells, two protein-binding regions showed no effect on basal transcriptional activity and the other two domains significantly downregulated transcription of the promoter. We conclude that cell type-specific transcription of the JCV early promoter is under both positive and negative regulation in eucaryotic cells.

Excision of Bartholin duct cysts using the CO2 laser

Many methods have been used to treat cystic enlargement of the duct of the Bartholins gland. Widely used methods have the disadvantage of recurrence, hemorrhage, persistent drainage, or considerable scarring. The carbon dioxide laser offers a simple and effective means of treating cystic Bartholin ducts. Ten patients were treated with the CO2 laser. The cyst was incised with the laser and the cyst wall was vaporized from the inside. In a follow-up period of one to four years, there were only two recurrences, and these responded to a second treatment. Surgery was rapid and uncomplicated in all cases, and healing occurred without scar formation. The CO2 laser offers several advantages over conventional methods for treating cysts of the Bartholin duct.

Acute inversion of the uterus

Acute inversion of the uterus is a rare emergency that occurs during the third stage of labor. Three cases of this complication are reported. General anesthesia, fundal pressure on a soft uterus, fundal implantation of the placenta, and adherent placenta were identified as the possible causes. Prompt recognition and replacement are essential in the management to preempt morbidities and mortality. The prevention, etiology, and management of this serious complication are discussed.