Background/objectives:Thyroid nodule (TN) is a common thyroid disorder globally, and the incidence has been increasing in recent decades. The objective of this study was to determine the contribution of thyroid-stimulating hormone (TSH), ultrasound (US), and cytological classification system for predicting malignancy among the surgically excised nodules.Design and methods:A retrospective analysis was performed between January 2012 and December 2014, using data drawn from 1188 patients (15-90 years), who had 1433 TN and fine-needle aspiration in Prince Sultan Military Medical City, Saudi Arabia. After reviewing all the thyroid cytopathological slides and US reports, classification was done based on the Bethesda System for Reporting Thyroid Cytology and the Thyroid Imaging Reporting and Data System (TI-RADS).Results:A total of 1188 patients’ medical records were reviewed for this study, among them 311 patients had undergone surgical intervention (253 patients had single nodule and 58 had 2 nodules), with a total of 369 nodules. However, as 54 nodules on the US were either unavailable or unclear, the 315 remaining nodules were analyzed, revealing 30.2% (n = 95) malignancy overall. Patients with TSH values of >4.5 mIU/L (38.2%), TN <1 cm (48.8%), TI-RADS category 5 (75.6%), and Bethesda category VI (88.9%) revealed a higher percentage of malignancy. From the univariate analysis using the χ2 test, significant relationship between the TSH, nodule size, TI-RADS, and the Bethesda category between the malignant and benign nodules emerged. The regression analysis showed that patients with a TSH value of 0.5 to 4.5 mIU/L (odds ratio [OR]: 2.96), TSH >4.5 mIU/L (OR: 6.54) had higher risk for malignancy than those with a TSH value of ≤0.4 mIU/L. Thyroid nodules with sizes of 1 to 1.9 cm (OR: 1.12), 2 to 2.9 cm (OR: 0.74), 3-3.9 cm (OR: 1.21), and ≥4 cm (OR: 0.52) were found to have no association with the risk of malignancy. Compared with TI-RADS 2 patients, those with categories 4B (OR: 1.35) and 5 (OR: 2.3) were found to be at higher risk of malignancy. Similarly, Bethesda IV (OR: 2.72), V (OR: 8.47), and VI (OR: 20; P < .02) category patients had a higher risk for malignancy than those in Bethesda class I. Among the study population, the papillary thyroid carcinoma was the most common type of thyroid cancer (86, 90.5%) followed by 7.4% (n = 7) of follicular thyroid carcinoma, 1.05% (n = 1) of anaplastic carcinoma, and 1.05% (n = 1) of medullary thyroid carcinoma.Conclusions:A predictive model for risk of malignancy using a combining characteristic of the TSH, US, and cytological classification systems could assist the clinicians in minimizing exposing the patients with TNs to nonessential invasive procedures.

AIMTo stratify the malignancy risks in thyroid nodules in a tertiary care referral center using the Bethesda system.METHODSFrom January, 2012 to December, 2014, a retrospective analysis was performed among 1188 patients (15-90 years) who had 1433 thyroid nodules and fine-needle aspiration at Prince Sultan Military Medical City, Saudi Arabia. All thyroid cyto-pathological slides and ultra sound reports were reviewed and classified according to the Bethesda System for Reporting Thyroid Cytopathology. Age, gender, cytological features and histological types of the thyroid cancer were collected from patients’ medical chart and cytopathology reports.RESULTSThere were 124 total cases of malignancy on resection, giving an overall surgical yield malignancy of 33.6%. Majority of the thyroid cancer nodules (n = 57, 46%) in Bethesda VI category followed by Bethesda IV (n = 25, 20.2%). Almost 40% of the cancer nodules in 31-45 age group in both sex. Papillary thyroid carcinoma (PTC) was the most common form of thyroid cancer among the study population (111, 89.6%) followed by 8.9% of follicular thyroid carcinoma (FTC), 0.8% of medullary carcinoma and 0.8% of anaplastic carcinoma. Among the Bethesda IV category 68% thyroid nodules were PTC and 32% FTC.CONCLUSIONThe malignancy values reported in our research were constant and comparable with the results of other published data with respect to the risk of malignancy. Patients with follicular neoplasm/suspicious for follicular neoplasm and suspicious of malignancy categories, total thyroidectomy is indicted because of the substantial risk of malignancy.

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Bacteriophages (phages) are the predominant biological entities on the planet and play an important role in the spread of bacterial virulence, pathogenicity, and antimicrobial resistance. After infection, temperate phages can integrate in the bacterial chromosome thanks to the expression of the prophage-encoded CI master repressor. Upon SOS induction, and promoted by RecA*, CI auto-cleaves generating two fragments, one containing the N-terminal domain (NTD), which retains strong DNA-binding capacity, and other corresponding to the C-terminal part of the protein. However, it is unknown how the CI NTD is removed, a process that is essential to allow prophage induction. Here we identify for the first time that the specific interaction of the ClpX protease with the CI NTD repressor fragment is essential and sufficient for prophage activation after SOS-mediated CI autocleavage, defining the final stage in the prophage induction cascade. Our results provide unexpected roles for the bacterial protease ClpX in phage biology.