Thyroid cancer (TC) is a common malignancy encountered at King Faisal Specialist Hospital and Research Centre (KFSH&RC). Of 19,885 different malignant tumors seen during the period from 1975 to 1989, there were 875 cases (4.4%) of TC. Of 1374 tumors of endocrine glands seen during the same period, 67% were thyroid neoplasms. TC represented 7.5% (618 cases) of all neoplasms in the females, second only to breast cancer. All types of TC were seen, with papillary thyroid carcinoma (PC) being the most common (79%). Anaplastic, medullary, follicular (FC), malignant lymphoma and Hürthle cell cancer accounted for 5.4%, 5.3%, 4.3%, 3.6% and 0.9% respectively. The frequency of PC was very similar (16%) in each of the third, fourth and fifth decades. The relative frequency (RF) of different types of TC was highest for PC with a ratio of 18:1 between PC and FC, which could be the highest ever reported. There was a clearly progressive increase in the number of thyroid tumors referred between 1975 and 1989. Although this increase was evident for both sexes, it was more apparent for females. There was also a distinct increase ( P<0.01) in the RF of PC from 76% (1975 to 1980) to 85% (1986 to 1989) Fifteen-Year Period (1975 at the King Faisal Specialist Hospital and Research Centre. 1995; 15(6): 579-584 Differentiated thyroid cancer (DTC) is a relatively common malignancy with a marked international variation in the incidence of the disease. Limited data are available on the incidence and clinicopathological features of TC from the Middle East.1-23 Pertinent information regarding the demographic, epidemiological, clinical and pathological features of TC from Saudi Arabia is needed to determine the prognostic factors and to develop effective management strategies.Information on the geographical distribution of cancer has been of great value for generation of epidemiologic hypothesis and formulation of concepts for the etiology of cancer. Such information would also be valuable for making global comparisons. Until a population-based tumor registry is established in Saudi Arabia and the figures for TC made available, the only other recourse is to analyze the experience emanating from large referral centers. It is in this context that we have embarked on a study of 928 consecutive cases of thyroid tumors, observed over a 15-year period (1975 to 1989) at the King Faisal Specialist Hospital and Research Centre. The specific aims of this work were: 1) To analyze the demographic features of patients with TC seen at our institution since its inception in 1975. 2) To classify and determine the crude relative frequency (CRF) of different thyroid tumors seen at KFSH&RC between 1975 and. CRF is the proportion of a given type of cancer in relation to all cases in a clinical or pathological series. 3) To determine any possible trend in the CRF of different types of TC seen at our institution. Patients and MethodsSince its inception in November 1975, we have had 1500 cases of thyroid tumors at KFSH&RC. However, this

Ten patients with tuberculous enterocolitis were diagnosed colonoscopically. In four, the diagnosis was confirmed by positive acid fast stain or the presence of caseating granuloma in colonic biopsy material or ileal washings. In one other patient a cervical lymph gland revealed acid-fast bacilli. He was the only patient with extraintestinal disease, indicating that primary tuberculous colitis is probably more common than secondary in Saudi Arabia. In the other five patients the colonoscopic diagnosis was confirmed by a complete response to antituberculous triple therapy. Six patients had hypertrophic, two ulcerohypertrophic and two widespread ulcerative lesions. Colonoscopy with biopsies has definite advantages over barium enema in diagnosis. After thus excluding malignancy, Crohn's disease remains the most important differential diagnosis. A ten-week therapeutic trial of antituberculous treatment is recommended in patients from high-risk populations with a typical history and colonoscopic picture to avoid the morbidity and mortality of diagnostic laparotomy.

New variants of SARS-CoV-2 are being reported worldwide. More specifically, the variants reported in South Africa (501Y.V2) and United Kingdom (B.1.1.7) were found to be more contagious than the wild type. There are also speculations that the variants might evade the host immune responses induced by currently available vaccines and develop resistance to drugs under consideration. The first step of viral infection in COVID-19, occurs through the interaction of receptor binding domain (RBD) of the spike protein with peptidase domain of the human ACE-2 (hACE-2) receptor. So, possibly the mutations in the RBD domain of spike protein in the new variants could modulate the protein-protein interaction with hACE-2 receptor leading to the increased virulence. In this study, we aim to get molecular level understanding into the mechanism behind the increased infection rate due to such mutations in these variants. We have computationally studied the interaction of the spike protein in both wild-type and B.1.1.7 variant with hACE-2 receptor using combined molecular dynamics and binding free energy calculations using molecular mechanics-Generalized Born surface area (MM-GBSA) approach. The binding free energies computed using configurations from minimization run and low temperature simulation show that mutant variant of spike protein has increased binding affinity for hACE-2 receptor (i.e. ΔΔG(N501Y,A570D) is in the range −20.4 to −21.4 kcal/mol)The residue-wise decomposition analysis and intermolecular hydrogen bond analysis evidenced that the N501Y mutation has increased interaction between RBD of spike protein with ACE-2 receptor. We have also carried out calculations using density functional theory and the results evidenced the increased interaction between three pairs of residues (TYR449 (spike)-ASP38 (ACE-2), TYR453-HIE34 and TYR501-LYS353) in the variant that could be attributed to its increased virulence. The free energies of wild-type and mutant variants of the spike protein computed from MM-GBSA approach suggests that latter variant is stable by about −10.4 kcal/mol when compared to wild type suggesting that it will be retained in the evolution due to increased stability. We demonstrate that with the use of the state-of-the art of computational approaches, we can in advance predict the more virulent nature of variants of SARS-CoV-2 and alert the world health-care system.

Extension of P1 is very inefficient with this 6-month regimen. Operational research should define appropriate algorithms allowing an earlier switch to the next higher regimen for those in need, using follow-up smears for screening.

Cytomorphologic features in a series of fine-needle aspiration biopsies from eight patients with seminoma or dysgerminoma were reviewed, and the findings were further correlated with histopathologic and ultrastructural appearances. Three cell types were encountered. Type I was least differentiated and least frequent. Type II was most frequent and had well-developed cytoplasm rich in organelles. Type III was similar to type II but also contained abundant cytoplasmic glycogen. In cytology smears, type III cells contained large punched-out cytoplasmic vacuoles corresponding to the areas of glycogen deposition. The background contained a variable mixture of inflammatory cells including lymphocytes, plasma cells, epithelioid cells, and epithelioid granulomas. The significance of these findings in the diagnosis of seminoma or dysgerminoma and the distinction from other germ-cell and non-germ-cell tumors is briefly discussed.