The effects of the promotor region of the 240bp repeats of the rRNA genes on x-y chromosome disjunction in Drosophila melanogaster males

Pairing between homologous chromosomes is essential for successful meiosis. In Drosophila melanogaster males, sex chromosome pairing during meiosis I is mediated by rDNA, located in heterochromatin. Several analyses of rDNA fragments showed that 240bp repeats in the intergenic spacer (IGS) have the ability to stimulate X-Y chromosome pairing and disjunction. In addition, point mutations within the promoter of the 240bp repeats failed to mediate X-Y chromosome pairing and disjunction. These previous studies imply that promoter activity of the 240bp repeats is involved in X-Y chromosome pairing in Drosophila males. In this study, I made a construct composed of 16 copies of the 72bp fragment within the 240bp repeat, which has promoter activity and obtained transformant lines with the construct. The construct was transferred to Df(1)X-1, an rDNA deficient X chromosome, by recombination. The effect of the transgene on the frequency of X-Y disjunction were analyzed both by cytological and genetic experiments. The transgene in Df(1)X-1 chromosome induced increased X-Y chromosome disjunction frequency. The result indicates that promoter activity of the 240bp repeats may be responsible for X-Y chromosome pairing in Drosophila males

Inhibition of Angiogenesis using RNAi technology

Ocular infection of Herpes Simplex Virus-1 (HSV-1) causes Herpetic Stromal Keratitis (HSK), which is a leading cause of infectious blindness. Although complex interactions of molecular and cellular events involve in the department of HSK, it has been known that angiogenesis is a key step for the HSK pathogenesis. Treatment of neutralizing antibody against vascular endothelial growth factor (VEGF) to inhibit VEGF activity reduced angiogenesis and HSK severity caused by infection of HSV-1 in mouse eyes. In addition, inactivation of cytokine which induces VEGF production and angiogenesis also reduced angiogenesis and HSK severity. Therefore, it has been proposed that VEGF or molecules which induce VEGF production or angiogenesis can be good target molecules for treating HSK. In this study, we investigated whether targeting VEGF or IL-1 receptor type I (IL-1RI) using RNAi technology could reduce angiogenesis in mouse eyes. A general introduction and overview of RNAi were provided in Part I. Results in Part II demonstrated that intrastromal injection of VEGF short hairpin RNA (shRNA) could reduce VEGF production and angiogenesis caused by CpG motif in mouse eyes. Implantation of pellets containing bio-active CpG motifs following intrastromal injection with a plasmid expressing shRNA against VEGF reduced angiogenesis and VEGF production. Results in Part III showed that intrastromal injection of IL-1RI shRNA could reduce angiogenesis caused by IL-1O through reduction of VEGF production. The results in this dissertation indicate that targeting VEGF or IL-1RI using RNAi technology can reduce angiogenesis in mouse eyes. Additionally, these results imply that an eye is a suitable organ to apply RNAi technology. Thus, this technology may help to understand corneal biology as well as to treat corneal diseases in the near future

Field evaluation of physical barriers against subterranean termites and ambrosia beetles in a CLT wall envelope system

The effectiveness of physical barriers against subterranean termites was evaluated in a 34-week field test in coastal Mississippi by installing Obex11, a commercial polyethylene flashing, and Termimesh, a stainless-steel mesh in 3-ply 280mm(width) x 450mm(length) cross laminated timber (CLT) walls. Damage showed that both barriers performed significantly better than the no barrier control with respect to termite damage as evaluated by visual rating and mud tube length.  Obex11, however, like the no barrier control, was more vulnerable to attack by Ambrosiodmus minor (Stebbing), an invasive ambrosia beetle, with both treatments exhibiting significantly longer bore trails than those found in Termimesh.&nbsp

Radiographic and computed tomographic evaluation of experimentally induced lung aspiration sites in dogs

This study was performed to radiographically examine the prevalence of aspiration sites and to evaluate their atomical correlation with the bronchial pattens. Ten healthy beagle dogs were repeatedly radiographed, at weekly intervals, in the left and right lateral, ventrodorsal (VD) and dorsoventral (DV) positions. Three mililiters of iohexol distilled with same volume of saline was infused into the tracheal inlet. Which lung lobe was aspirated was decided upon by the presence of a significant alveolar pattern due to the contrast medium. Alveolar patterns were identified at the left (100%) and right cranial lung lobes (77%) with the dogs in dependant lateral recumbency, at the right caudal lung lobe (71%) with the dogs in VD recumbency and at the right middle lung lobe (59%) with the dogs in DV recumbency, respectively. The anatomical correlation was evaluated by performing computed tomography. The right principal bronchus (165.8 ± 1.6°) was more straightly bifurcated than was the left principal bronchus (142.7 ± 1.8°, p < 0.01). In VD position, the right side lung had a greater opertunity to become aspirated. The ventrally positioned right middle lobar bronchial origin was more easily to be aspirated the other laterally positioned ones. We think that these anatomical characteristics can be one of the causes for aspiration pneumonia to occur more frequently in the right side lung

Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 ± 1.02 mm, p = 0.001) than that in inspiration (9.86 ± 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 ± 1.52 mm, p = 0.001) than in inspiration (8.02 ± 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 ± 1.01 mm, p = 0.001) than in inspiration (14.85 ± 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 ± 0.09) than that in inspiration (0.79 ± 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 ± 0.09) and inspiration (1.47 ± 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis

Clinical application of the Panbio™ COVID-19 Ag rapid test device and SSf-COVID19 kit for the detection of SARS-CoV-2 infection

Objective We evaluated the sensitivity and specificity of the Panbio™ COVID-19 Ag rapid test device using nasal swabs and those of the SSf-COVID19 kit, one of RT-PCR tests, using saliva specimens. These tests were compared with RT-PCR tests using nasopharyngeal swabs for the diagnosis of SARS-CoV-2 infection. The three diagnostic tests were simultaneously conducted for patients aged ≥ 18 years, who were about to be hospitalized or had been admitted for COVID-19 confirmed by RT-PCR in two research hospitals from August 20 to October 29, 2021. Nasal swabs were tested using the Panbio™ COVID-19 Ag rapid test device. More than 1 mL of saliva was self-collected and tested using the SSf-COVID19 kit. Results In total, 157 patients were investigated; 124 patients who were about to be hospitalized and 33 patients already admitted for COVID-19. The overall sensitivity and specificity of the Panbio™ COVID-19 Ag rapid test device with nasal swabs were 64.7% (95% confidence interval [CI] 47.9–78.5%) and 100.0% (95% CI 97.0–100.0%), respectively. The median time to confirm a positive result was 180 s (interquartile range 60–255 s). The overall sensitivity and specificity of the SSf-COVID19 kit with saliva specimens were 94.1% (95% CI 80.9–98.4%) and 100.0% (95% CI 97.0–100.0%), respectively.This work was supported by a grant from research fund of Seoul National University Hospital (Grant No. 2021–3148

Classification of the Relationship Between Mandibular Third Molar and Inferior Alveolar Nerve Based on Generated Mask Images

In recent dentistry research, deep learning techniques have been employed for various tasks, including detecting and segmenting third molars and inferior alveolar nerves, as well as classifying their positional relationships. Prior studies using convolutional neural networks (CNNs) have successfully detected the adjacent area of the third molar and automatically classified the relationship between the inferior alveolar nerves. However, deep learning models have limitations in learning the diverse patterns of teeth and nerves due to variations in their shape, angle, and size across individuals. Moreover, unlike object classification, relationship classification is influenced by the proximity of teeth and nerves, making it challenging to accurately interpret the classified samples. To address these challenges, we propose a masking image-based classification system. The primary goal of this system is to enhance the classification performance of the relationship between the third molar and inferior alveolar nerve while providing diagnostic evidence to support the classification. Our proposed system operates by detecting the adjacent areas of the third molar, including the inferior alveolar nerve, in panoramic radiographs (PR). Subsequently, it generates masked images of the inferior alveolar nerve and third molar within the extracted regions of interest. Finally, it performs the classification of the relationship between the third molar and inferior alveolar nerve using these masked images. The system achieved a mean average precision (mAP) of 0.885 in detecting the region of interest in the third molar. Furthermore, the performance of the existing CNN-based positional relationship classification was evaluated using four classification models, resulting in an average accuracy of 0.795. For the segmentation task, the third molar and inferior alveolar nerve in the detected region of interest exhibited a dice similarity coefficient (DSC) of 0.961 and 0.820, respectively. Regarding the proposed masking image-based classification, it demonstrated an accuracy of 0.832, outperforming the existing method by approximately 3&#x0025;, thus confirming the superiority of our proposed system