Red Blood Cell Susceptibility to Pneumolysin: CORRELATION WITH MEMBRANE BIOCHEMICAL AND PHYSICAL PROPERTIES.

This study investigated the effect of the biochemical and biophysical properties of the plasma membrane as well as membrane morphology on the susceptibility of human red blood cells to the cholesterol-dependent cytolysin pneumolysin, a key virulence factor of Streptococcus pneumoniae, using single cell studies. We show a correlation between the physical properties of the membrane (bending rigidity and surface and dipole electrostatic potentials) and the susceptibility of red blood cells to pneumolysin-induced hemolysis. We demonstrate that biochemical modifications of the membrane induced by oxidative stress, lipid scrambling, and artificial cell aging modulate the cell response to the toxin. We provide evidence that the diversity of response to pneumolysin in diabetic red blood cells correlates with levels of glycated hemoglobin and that the mechanical properties of the red blood cell plasma membrane are altered in diabetes. Finally, we show that diabetic red blood cells are more resistant to pneumolysin and the related toxin perfringolysin O relative to healthy red blood cells. Taken together, these studies indicate that the diversity of cell response to pneumolysin within a population of human red blood cells is influenced by the biophysical and biochemical status of the plasma membrane and the chemical and/or oxidative stress pre-history of the cell.

Accuracy of Ultrasound and Computed Tomography in Diagnosing Acute Cholecystitis Patients in a Tertiary Care Center in Saudi Arabia.

Background Acute cholecystitis (AC) is a gallbladder inflammatory disease often associated with gallbladder stones. It accounts for up to 5% of emergency department visits. The majority of patients present with pain in the right upper quadrant, Murphy's sign, and fever. Furthermore, Saudi Arabia has been noted to have a significant prevalence of AC. According to the 2018 Tokyo Guidelines, imaging is an essential element, combined with local and systemic evidence of inflammation, for a confirmed diagnosis of AC. The definitive therapy is conducted surgically by cholecystectomy either urgently or electively. However, there are insufficient studies that focus on the accuracy of imaging in diagnosing AC patients in Saudi Arabia. Objective The aim of this study is to assess the accuracy of ultrasound (US) versus computed tomography (CT) in diagnosing AC patients at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. Methods and material A retrospective record review was conducted at KAUH during the period of June to July 2022. The study included 192 patients diagnosed with AC in the emergency department or outpatient department by US or CT or both and confirmed by laparoscopic cholecystectomy and histopathology between 2016 and 2022. Results The most common modality used was US (79.7%), followed by both US and contrast CT (10.9%). For CT, sensitivity was 81.3%, specificity was 62.5%, positive predictive value (PPV) was 59.1%, and negative predictive value (NPV) was 83.3%. For US, sensitivity was 37.9%, specificity was 81.7%, PPV was 50%, and NPV was 73.1%. A significant relationship was observed between both genders and high use of US (P = 0.0001). Conclusion We found that CT is more sensitive than US, while US is more specific in diagnosing AC.

Artificial intelligence in radiology: Are Saudi residents ready, prepared, and knowledgeable?

OBJECTIVES: To assess the knowledge and perception of artificial intelligence (AI) among radiology residents across Saudi Arabia and assess their interest in learning about AI. METHODS: An observational cross-sectional study carried out among radiology residents enrolled in the Saudi Board of Radiology, Saudi Arabia. An anonymized, self-administered questionnaire was distributed in April 2020 and responses were collected until July 2020. RESULTS: A total of 154 residents filled the questionnaire. The top 3 aspects of AI participants wanted to learn were: clinical use of AI applications, advantages and limitations of AI applications, and technical methods. Approximately 43.5% of participants did not expect AI to affect job positions, while 42% anticipated that job positions will decrease. Approximately 53% expected a reduction in reporting workload, while 28% expected an increase in workload. CONCLUSION: Currently, the exposure of radiologists to the use of AI is inadequate. It is imperative that AI is introduced to radiology trainees and that radiologists stay updated with advances in AI to be more knowledgeable on how to benefit from it.

How has the COVID-19 pandemic affect the rejection rates and repeat reasoning of digital radiography?

OBJECTIVES: To compare the digital radiology rejection rates and reasoning pre-COVID-19 (PC) and during COVID-19 (DC) from September 2019 to August 2020. METHODS: This record-base retrospective study where data were extracted from the radiography equipment (Carestream Health, Rochester, New York, USA) at the Department of Radiology, King Abdulaziz University Hospital, Jeddah, Saudi Arabia over 12 months. The data were equally divided into PC and DC. RESULTS: The DC rejection rate decreased from PC by 2.6% with a significant p=0.00001. During COVID-19 there were 15,376 images of different body parts, versus 23,861 images during PC. Position errors were the main reasons for rejection for both PC (39.8%) and DC (42.7%), followed by technique errors (PC: 19.2%) (DC: 17.2%). CONCLUSION: Different sectors in hospitals were affected by COVID-19, including diagnostic radiology, in the positive direction. Thus, the DC rejection rate was markedly reduced compared with PC. This may be due to radiology technicians becoming more cautious in dealing with patients.

Prevalence of Diabetes and Hypertension Among King Abdulaziz University Employees: Data From First Aid and Cardiopulmonary Resuscitation Training Program.

Objectives Saudi Arabia has a very high rate of chronic illnesses, especially hypertension (HTN) and diabetes. This study aimed to investigate the prevalence and control of diabetes and hypertension among employees at a university in Saudi Arabia, including the associated risk factors, and to evaluate the need for early screening among these individuals. Methods This retrospective study used data from the first aid training program. In total, there were 3964 employees who completed the program, and only 1000 employees were enrolled. The program was conducted at King Abdulaziz University (KAU), Jeddah, Saudi Arabia. Blood pressure (BP), random blood sugar, and body mass index (BMI) were measured in all employees. Descriptive data, including mean, standard deviation (SD), crosstab, chi-square, and linear regression, were analyzed. Categorical variables were described using frequencies and percentages. Results The prevalence of hypertension and diabetes was 31% and 5%. There were 365 males and 635 females. Employees with risk factors such as gender, age, and body mass index had significant effects on having high blood pressure and random blood glucose measurements. Of the employees who reported being free from chronic diseases, 2.9% had abnormal random blood glucose readings (prediabetic and diabetic ranges), while 37.4% had abnormal blood pressure readings (prehypertensive and hypertensive ranges). Conclusion The high prevalence of hypertension and diabetes reflects the crucial role of early screening in diabetes and hypertension protocols and raising awareness regarding protocol implementation in Saudi Arabia to improve quality of life (QoL) at the individual and community levels.

The effect of varying cone beam computed tomography image resolution and field-of-view centralization on effective radiation dose.

OBJECTIVES: To investigate changes in the effective radiation dose (E) in relation to variations in voxel (VOX) size settings and the field-of-view (FOV) centralization. Methods: This cross-sectional dosimetry study used nanoDot OSLD dosimeters placed at 25 pre-determined sites in the head and neck slices of a RANDO male phantom to measure the absorbed radiation. The imaging scans took place at King Abdulaziz University Dental Hospital, Jeddah, Saudi Arabia between September 2016 and May 2017 using the i-CAT classic cone beam computed tomography (CBCT)  unit. Three VOX size setting were examined: 0.2 mm, 0.3 mm and 0.4 mm. The FOV was alternatively eccentrically centered on the maxillary and mandibular arches while holding all other factors constant. Effective radiation doses were calculated for each VOX size and FOV centralization setting. Results: An inverse and indirect relation was found between E and the VOX size setting with smaller VOX yielding higher E. CBCT scans centered on the mandible resulted in higher E than scans centered on the maxilla. Conclusion: Effective radiation doses are significantly affected by changes in VOX size settings and FOV centralization options. This reflects on the potential radiation risk to patients and highlights the importance of choosing exposure parameters carefully.

Direct digital radiograph. Technicians role in obtaining good images.

OBJECTIVES: To determine the rejected rate of direct digital radiography (DRs) in our hospital, benchmark it with other institutes, and explore the causes of rejection. METHODS: Data were collected between June 2012 and May 2013 at King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia. The rejected analysis was registered in the system, which is a built in software. Reasons for rejection could not be deleted, and no further imaging is allowed for the same patient without reporting the reason for rejection. Reasons for rejection are predefined by the machine. RESULTS: Of 89,797 images that were acquired, 13,371 were rejected, with a rejection rate of 15%. Positioning errors were the main reason for rejection, followed by artifact 28.5%, and motion 17.1%. As for body parts pelvis, abdomen, spine, and knee were recorded as rejected with higher rates than the average. CONCLUSION: This study has shown a number of unnecessary repeated imaging of patients. In addition, reject analysis in DR is proven to be an indicator for quality in imaging, the reasons of rejection that have high percentage for occurrence should be given more focus during patients scan. 

Medical students' knowledge of ionizing radiation and radiation protection.

OBJECTIVE: To assess the knowledge of fourth-year medical students in ionizing radiation, and to study the effect of a 3-hour lecture in correcting their misconceptions. METHODS: A cohort study was conducted on fourth-year medical students at King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia during the academic year 2009-2010. A 7-question multiple choice test-type questionnaire administered before, and after a 3-hour didactic lecture was used to assess their knowledge. The data was collected from December 2009 to February 2010. The lecture was given to 333 (72%) participants, out of the total of 459 fourth-year medical students. It covered topics in ionizing radiation and radiation protection. The questionnaire was validated and analyzed by 6 content experts. RESULTS: Of the 333 who attended the lecture, only 253 (76%) students completed the pre- and post questionnaire, and were included in this study. The average student score improved from 47-78% representing a gain of 31% in knowledge (p=0.01). CONCLUSION: The results indicated that the fourth-year medical students' knowledge regarding ionizing radiation and radiation protection is inadequate. Additional lectures in radiation protection significantly improved their knowledge of the topic, and correct their current misunderstanding. This study has shown that even with one dedicated lecture, students can learn, and absorb general principles regarding ionizing radiation.