Prevalence and correlates of COVID-19 vaccine hesitancy among the elderly in Qatar: A cross-sectional study

Older individuals are more vulnerable to severe coronavirus disease 2019 and medical complications. Vaccination stands as an efficient and safe vanguard against infection. However, negative attitudes and perceptions pertaining to available vaccines might hinder community inoculation. The aim of this study was to assess vaccine hesitancy and its psychosocial determinants among the elderly in Qatar.We conducted a cross-sectional study between October 15 and November 15, 2020, using a composite online survey including the Vaccine Attitudes Examination Scale in addition to questions on sociodemographic correlates and the role of healthcare professionals.The vaccine hesitancy rate was 19.5%. The main reasons for willingness to vaccinate included understanding the nature of disease and role of vaccination, in addition to information provided by physicians. Fears mainly centered around vaccine safety. Vaccine hesitators were more likely to be non-Qatari and having received the influenza vaccine at least once. Gender, marital status, socioeconomic status, educational level, and having completed childhood vaccinations were not associated with vaccine hesitancy.Efforts should be directed toward raising awareness of vaccine efficacy and safety profiles. Physicians should additionally be educated about their pivotal role in advocating vaccine acceptance. We recommend reassessing vaccine hesitancy and its associated factors following a year of campaigning and vaccine administration to identify and target vulnerable groups.     

Optimization-Based Economical Flexural Design of Singly Reinforced Concrete Beams: A Parametric Study

In the past, many studies have been conducted on the optimization of reinforced concrete (RC) structures. These studies have demonstrated the effectiveness of different optimization techniques to obtain an economical design. However, the use of optimization techniques to an obtain economical design is not so practical due to the difficulty in applying most of the optimization techniques to achieve an optimal solution. The RC beam is one of the most common structural elements encountered by a practising design engineer. The current study is designed to highlight the potential of the Solver tool in MS Excel as an easy-to-use option for optimizing the design of simply supported RC beams. A user-friendly interface was developed in a spreadsheet in which beam design parameters from a typical design can be entered and an economical design can be obtained using the Evolutionary Algorithm available in the MS Excel Solver tool. To demonstrate the effectiveness of the developed optimization tool, three examples obtained from the literature have been optimized. The results showed that up to 24% economical solution can be obtained by keeping the same material strengths that were assumed in the original design. However, if material strength is also considered as a variable, up to 44% of the economical solution can be obtained. A parametric study was also conducted to investigate the effect of different design variables on the economical design of simply supported RC beams and to derive useful rules of thumb for their design and proportioning, with the objective of cost minimization. The results of the parametric study suggest that the grade of the reinforcing steel is one of the most influential factors that affect the cost of simply supported RC beams. Practicing engineers can use the trends derived from this research to further refine their optimal designs.     

N-Phenylethyl Amitriptyline in Rat Sciatic Nerve Blockade

Background: The antidepressant amitriptyline is commonly used orally for the treatment of chronic pain, particularly neuropathic pain, which is thought to be caused by high-frequency ectopic discharge. Among its many properties, amitriptyline is a potent Na+ channel blocker in vitro, has local anesthetic properties in vivo, and confers additional blockade at high stimulus-discharge rates (use-dependent blockade). As with other drug modifications, adding a phenylethyl group to obtain a permanently charged quaternary ammonium derivative may improve these advantageous properties.

Methods: The electrophysiologic properties of N-phenylethyl amitriptyline were assessed in cultured neuronal GH3 cells with the whole cell mode of the patch clamp technique, and the therapeutic range and toxicity were evaluated in the rat sciatic nerve model.

Results: In vitro, N-phenylethyl amitriptyline at 10 [mu]m elicits a greater block of Na+ channels than amitriptyline (resting block of approximately 90%vs. approximately 15%). This derivative also retains the attribute of amitriptyline in evoking high-degree use-dependent blockade during repetitive pulses. In vivo, duration to full recovery of nociception in the sciatic nerve model was 1,932 +/- 72 min for N-phenylethyl amitriptyline at 2.5 mm (n = 7) versus 72 +/- 3 min for lidocaine at 37 mm (n = 4; mean +/- SEM). However, there was evidence of neurotoxicity at 5 mm.     

Assessment of the relationship between asymmetric dimethylarginine and severity of erectile dysfunction and coronary artery disease

The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been linked to endothelial dysfunction. We investigated the relation between plasma ADMA concentration and severity of erectile dysfunction (ED) and coronary artery disease (CAD). We measured plasma levels of ADMA in 92 male patients. Patients were divided into three groups: group 1 (n = 41), patients with ED and without CAD; group 2 (n = 29), patients with stable CAD; group 3 (n = 22), control group (patients without CAD or ED). Erectile function was evaluated by the erectile function domain of the international index of erectile function (IIEF-EFD) a validated 15-item self-administered questionnaire. Erectile function is specifically addressed by six questions that form the so-called erectile function domain of the questionnaire. Each question is scored 0–5. ED is defined as any value <26. Patients with CAD who have stable angina pectoris were selected after coronary angiography. ADMA was analyzed by ELISA method. Group 1 had significantly higher concentrations of plasma ADMA than groups 2 and 3 (respectively, 0.75 ± 0.40 vs. 0.50 ± 0.30, P = 0.013; 0.75 ± 0.40 vs. 0.50 ± 0.25, P = 0.021). There was negative correlation between ADMA and IIEF-EFD score in all groups (n = 92) (r = −0.322, P = 0.002). In a multiple logistic regression analysis adjusting for age, hyperlipidemia, ADMA remained independent predictor for severe ED. Odds ratio for plasma ADMA was 14.151 (1.101–181.940; P = 0.042). First of all, this study provides that ADMA concentrations are significantly higher in patients who have ED when compared to patients with CAD and controls. Second, there was a negative correlation between ADMA and severity of ED. Elevating levels of circulating ADMA is an independent risk factor for severe of ED, and ADMA may be a link between CAD and ED.     

Intrathecal catheterization after unintentional dural puncture during orthopedic surgery

Purpose

We investigated whether inserting an intrathecal catheter and leaving it in place for 24 h after an unintentional dural puncture in orthopedic patients reduced the incidence of post-dural puncture headache (PDPH).

Methods

The study consisted of 427 patients in whom a total of 21 unintentional dural punctures had occurred during orthopedic surgery performed between 2002 and 2006. Seven patients (phase I; evaluated retrospectively) each underwent placement of an epidural catheter at another level after dural puncture during the period January 2002 to February 2004. Fourteen patients (phase II; evaluated prospectively) received an epidural catheter through the dural tear after an unintentional dural puncture during the period February 2004–March 2006

Results

In phase I, 5 of the 7 patients experienced PDPH, and one required an epidural blood patch. In phase II, only one of the 14 patients complained of PDPH, which resolved after 48 h of medical therapy. No patient experienced paresthesia, neurologic or hemorrhagic complication, or infection.

Conclusion

Inserting an epidural catheter through the dural tear following an unintentional dural puncture and leaving it in place for 24 h significantly reduces the incidence of PDPH.     

Plating after lengthening (PAL): technical notes and preliminary clinical experiences

Introduction Shortening the period of time for the external fixator after limb lengthening decreases the complication rate and increases the patient satisfaction. Material and method We describe the plating after lengthening (PAL) as a new technique on five patients with limb length discrepancy (1 femoral, 4 tibial) who had lengthening procedure with Ilizarov technique. The mean amount of lengthening was 50 mm. The mean lengthening period was 100 days (5–135 days). When the lengthening period ended, the locking compression plate was applied percutaneously by using the technique of minimal invasive plate osteosynthesis, and the Ilizarov external fixator was removed. Results The fixator-free period was achieved at the beginning of the consolidation phase, except in two patients, which were delayed for plating because of pin-tract infection. No complication was encountered except in one patient who had limited flexion of knee joint. There was no need for blood transfusion. Discussion The PAL, which shortened the period of time for the external fixator, was an easy and safe method for the fixation of the bone after limb lengthening.     

Mitochondrial UCP4 mediates an adaptive shift in energy metabolism and increases the resistance of neurons to metabolic and oxidative stress

The high-metabolic demand of neurons and their reliance on glucose as an energy source places them atrisk for dysfunction and death under conditions of metabolic and oxidative stress. Uncoupling proteins (UCPs) are mitochodrial inner membrane proteins implicated in the regulation of mitochondrial membrane potential (ΔΨ_m) and cellular energy metabolism. The authors cloned UCP4 cDNA from mouse and rat brain, and demonstrate that UCP4 mRNA is expressed abundantly in brain and at particularly high levels in populations of neurons believed to have high-energy requirements. Neural cells with increased levels of UCP4 exhibit decreased ΔΨ_m, reduced reactive oxygen species (ROS) production and decreased mitochondrial calcium accumulation. UCP4 expressing cells also exhibited changes of oxygen-consumption rate, GDP sensitivity, and response of ΔΨ_m to oligomycin that were consistent with mitochondrial uncoupling. UCP4 modulates neuronal energy metabolism by increasing glucose uptake and shifting the mode of ATP production from mitochodnrial respiration to glycolysis, thereby maintaining cellular ATP levels. The UCP4-mediated shift in energy metabolism reduces ROS production and increases the resistance of neurons to oxidative and mitochondrial stress. Knockdown of UCP4 expression by RNA interference in primary hippocampal neurons results in mitochondrial calcium overload and cell death. UCP4-mRNA expression is increased in neurons exposed to cold temperatures and in brain cells of rats maintained on caloric restriction, suggesting a role for UCP4 in the previously reported antiageing and neuroprotective effects of caloric restriction. By shifting energy metabolism to reduce ROS production and cellular reliance on mitochondrial respiration, UCP4 can protect neurons against oxidative stress and calcium overload. These authors made equal contributions to this research.