Investigations into the Mass Spectrometric Method for the Determination of the Mode of Termination in Radical Polymerization

The fraction of termination by disproportionation, λ, in radical polymerization may be determined by a mass spectrometric (MS) analysis of the resulting polymer. It is subjected to an array of stringent consistency checks, working with polymerizations of methyl methacrylate at 85 °C in three different solvents and with four different initiators. λ is shown to be unaffected by the choice of initiator, initiator concentration, or isoviscous solvent. These findings serve to allay any fears about the method being undermined by effects such as primary radical termination or chain transfer to solvent, thereby establishing its robustness. At the same time, direct evidence for the occurrence of chain transfer to the solvent methyl isobutyrate is uncovered, and the importance of knowing other rate‐parameter values accurately, if λ is to be determined accurately, is illustrated. By carrying out MS analyses, it is concluded that electrospray ionization with time‐of‐flight detection gives the best results for the present purpose.

     

Stair climbing test predicts cardiopulmonary complications after lung resection

STUDY OBJECTIVE: To evaluate the capability of the stair climbing test to predict cardiopulmonary complications after lung resection for lung cancer. DESIGN: A prospective cohort of candidates for lung resection. Spirometric assessment and the stair climbing test were performed the day before operation. Univariate and multivariate analyses were performed to identify predictors of postoperative complications. SETTING: Tertiary referral center. PATIENTS: A consecutive series of 160 candidates for lung resection with lung carcinoma from January 2000 through March 2001. RESULTS: At univariate analysis, the patients with complications were significantly older (p = 0.02), had a significantly lower FEV(1) percentage (p = 0.007) and predicted postoperative FEV(1) percentage (p = 0.01), had a greater incidence of a concomitant cardiac disease (p = 0.02), climbed a lower altitude at the stair climbing test (p < 0.0001), and had a lower calculated maximum oxygen consumption (O(2)max) [p = 0.03] and predicted postoperative O(2)max (p = 0.006) compared to the patients without complications. At multivariate analysis, the altitude reached at the stair climbing test remained the only significant independent predictor of complications. CONCLUSIONS: The stair climbing test is a safe and economical exercise test, and it was the best predictor of cardiopulmonary complications after lung resection.     

Coronary artery disease among asymptomatic diabetic and nondiabetic patients undergoing coronary computed tomography angiography

OBJECTIVES: The aim of this study was to determine the prevalence and severity of coronary artery disease (CAD) and the plaque composition in asymptomatic diabetic and nondiabetic patients undergoing coronary computed tomography angiography (CCTA). BACKGROUND: CAD is the major cause of death among patients with diabetes. The true prevalence of CAD in asymptomatic diabetic patients, however, remains unknown. MATERIALS AND METHODS: A total of 328 consecutive patients (each with at least one risk factor or abnormal stress-test results) were referred for cardiac evaluation, 42 with diabetes and 286 without diabetes, all asymptomatic for cardiac-related symptoms. Groups were matched for age, sex, and CAD risk factors. CAD was defined as coronary atherosclerosis, with obstructive or nonobstructive lesions. CCTA was performed and findings compared between patients with diabetes and those without. RESULTS: CAD was present in 39 (93%) diabetic patients and in 211 (73%) nondiabetic patients (P=0.006). Obstructive CAD was more common in diabetic patients than in nondiabetic patients (29 vs. 6.6%, respectively; P<0.0001). In diabetic patients, more coronary segments with atherosclerosis per patient were detected (5.5 segments/patient vs. 2.8 segments/patient in nondiabetics; P<0.0001). The total Agatston score was significantly higher in diabetic patients vs. nondiabetic patients (370+/-96 and 79.9+/-16, respectively; P<0.0001). CONCLUSION: Our results indicate a high prevalence (93%) of CAD in asymptomatic diabetic patients with either nonobstructive or obstructive lesions. CCTA may be a useful imaging modality for selecting patients at high risk who would benefit most from further evaluation for subclinical ischemia.     

Long-stay patients in pediatric intensive care units: Five-years, 2-points,cross-sectional study

Objectives:To explore the changing patterns of long-stay patients (LSP) to improve the utilization of pediatric intensive care units (PICUs) resources.Methods:This is a 2-points cross-sectional study (5 years apart; 2014-2019) conducted among PICUs and SCICUs in Riyadh, Saudi Arabia. Children who have stayed in PICU for more than 21 days were included.Results:Out of the 11 units approached, 10 (90%) agreed to participate. The prevalence of LSP in all these hospitals decreased from 32% (48/150) in 2014 to 23.4% (35/149) in 2019. The length of stay ranged from 22 days to 13.5 years. The majority of LSP had a neuromuscular or cardiac disease and were admitted with respiratory compromise. Ventilator-associated pneumonia was the most prevalent complication (37.5%). The most commonly used resources were mechanical ventilation (93.8%), antibiotics (60.4%), and blood-products transfusions (35.4%). The most common reason for the extended stay was medical reasons (51.1%), followed by a lack of family resources (26.5%) or lack of referral to long-term care facilities (22.4%).Conclusion:A long-stay is associated with significant critical care bed occupancy, complications, and utilization of resources that could be otherwise utilized as surge capacity for critical care services. Decreasing occupancy in this multicenter study deserves further engagement of the healthcare leaders and families to maximize the utilization of resources.     

Oncology research in Saudi Arabia over a 10-year period: A synopsis

Objectives:To assess the quality and quantity of Saudi publications in oncology over a 10-year period.Methods:A systematic PubMed search was conducted between January 2008 and December 2017 to retrieve all Saudi oncology publications. Data about the articles was collected. The level of evidence (LOE) was independently assessed by 2 authors. Two 5-year periods (2008-2012 and 2013-2017) were compared using the relevant parameters. Clinicaltrials.gov was also searched for all oncology trials registered in Saudi Arabia.Results:A total of 839 publications met our inclusion criteria. The most common type of research was case series, totaling 32% of all publications. Clinical trials formed less than 2% of the total. The LOE was I, II, III, and IV in 0.3%, 2.1%, 58.4%, and 39.3% of the included publications, respectively. The LOE was the same in the 2 periods. There were more publications in international journals (p=0.004), more international collaborations (p=0.001), and higher journal impact factors (p=0.037) in 2013-2017 than in 2008-2012. Only 76 registered clinical trials were found in the Clinicaltrials.gov registry.Conclusion:Despite an increase in the number of Saudi publications in the field of oncology over time, the LOE did not change. There were, however, some improvements in the international collaboration and journal impact factor, as well as an increase in the number of studies published in international journals. These observations call for a national strategy to improve oncology research in Saudi Arabia.     

Social Impact of Dialysis on Children and Their Families

Objectives

To evaluate the social consequences of dialysis on children and their parents.

Methods

From January through June 2012 short structured interviews with parents or caregivers of children on peritoneal dialysis (PD) or hemodialysis (HD) who were followed up at King Abdulaziz University Hospital, King Faisal Specialty Hospital and Research Center, or the Kidney Center at King Fahad Hospital were conducted. Data were analyzed using the Statistical Package for the Social Sciences.

Results

Thirty six children (22 boys and 16 girls) and their families were included. The mean (SD) age of the children was 11.5?±?6.87 y, and the mean (SD) duration of dialysis was 28?±?11.32 mo. Only one third of the families had the opportunity to choose the modality of dialysis. Both modalities of dialysis had a negative effect on fathers’ jobs in over 50 % of the cases. Similarly, both modalities of treatment had a considerable impact on the quality of care provided by the mothers to other family members. There was no difference between the two modalities on the frequency of admissions.

Conclusions

Both PD and HD had a negative impact on fathers’ jobs and on the level of care provided by mothers to the rest of the family.