Amphiphilic and hydrophilic forms of choline-O-acetyltransferase in cholinergic nerve endings of the Torpedo

In the purely cholinergic nerve endings isolated (i.e. synaptosomes) from the electric organ of the fish Torpedo, the enzyme choline acetyltransferase was found to exist not solely in its well-known soluble form but also in a form which is non-ionically bound to the plasma membrane; this activity could not be solubilized in solutions of high ionic strength (0.5 M NaCl). The non-ionic detergent Triton X-114 was used to solubilize synaptosomes isolated from either the electric organ of Torpedo or rat brain. This detergent allows to separate hydrophilic from amphiphilic proteins of cells or subcellular fractions. Twelve per cent of the synaptosomal choline acetyltransferase partitioned as amphiphilic and 80-97% as hydrophilic activity. The percentage of amphiphilic activity present in synaptosomes was significantly higher than that of the form of activity (4.4%) extracted from samples containing only the soluble form of choline acetyltransferase but was significantly lower than the percentage of amphiphilic enzyme present in preparations of synaptosomal plasma membrane (20-22%) which were enriched in the non-ionically membrane-bound form of choline acetyltransferase. These results indicate that the soluble and the non-ionically membrane-bound enzymes differ in their capacity to interact with non-ionic detergents. The preparations of synaptosomal plasma membranes contained significantly higher proportions of detergent-insoluble choline acetyltransferase activity than did the whole synaptosomes; the difference was more striking for the Torpedo than for the rat enzyme. This detergent-insoluble activity was not due to aggregates of the enzyme. Some properties of the hydrophilic and amphiphilic choline acetyltransferase of Torpedo were analyzed. The two forms of the enzyme did not exhibit different affinities for their substrates; they were found to differ with respect to their sensitivity to inhibition by increasing concentrations of the two products of the reaction, acetylcholine and coenzyme A and heat inactivation at 45 degrees C. Most probably the hydrophilic and amphiphilic activities correspond to what was referred to as soluble and non-ionically membrane-bound choline acetyltransferase, respectively. The amphiphilic form may be an integral enzyme of the plasma membrane of cholinergic nerve endings or may be tightly bound to a specific protein in this membrane which may act as a "receptor" for choline acetyltransferase.     

Effects of voluntary wheel running and amino acid supplementation on skeletal muscle of mice

The aims of the present study were as follows: (1) to examine the adaptational changes to chronic endurance voluntary exercise and (2) to investigate the effects of amino acid supplementation on the adaptational changes induced by endurance training in hindlimb (gastrocnemius, tibialis, soleus) and respiratory (diaphragm) muscles of mice. Male C57Bl6 mice were divided in four groups: control sedentary, sedentary supplemented with amino acid mixture (BigOne, 1.5 mg g day^–1 in drinking water for 8 weeks), running (free access to running wheels for 8 weeks), and running supplemented with amino acid mixture. Myosin heavy chain (MHC) isoform distribution was determined in all muscles considered. Fiber cross-sectional area (CSA) was measured in the soleus muscle. In all muscles except the tibialis, endurance training was associated with an overall shift towards the expression of slower MHC isoforms. Amino acid supplementation produced a shift towards the expression of faster MHC isoforms in the soleus and diaphragm muscles, and partially antagonized the effects of training. Immunohistochemical analysis of CSA of individual muscle fibers from the soleus muscle suggests that voluntary running produced a decrease in the size of type 1 fibers, and amino acid supplementation during training resulted in an increase in size in both type 1 and type 2A fibers. Collectively, these results suggest that the endurance adaptations induced by voluntary running depend on the muscle type, and that amino acid supplementation is able to modulate both fiber size and MHC isoform composition of skeletal muscles in sedentary and exercised mice.     

Results and complications of percutaneous pelvic osteotomy and intertrochanteric varus shortening osteotomy in 54 consecutively operated GMFCS level IV and V cerebral palsy patients

Purpose

This retrospective study evaluated mid-to-long-term outcome of a minimally invasive percutaneous pelvic osteotomy (PPO) approach combined with varus derotational shortening osteotomy (VDRSO) and soft tissue release in children with severe CP.

Methods

A retrospective review was performed of all patients presenting with a diagnosis of CP with hip subluxation or dislocation treated surgically by simultaneous soft tissue release, VDRSO, and PPO between 2002 and 2015. Eligible patients included those with a diagnosis of spastic quadriplegia or CP GMFCS level IV or V with unilateral or bilateral hip subluxation or dislocation and surgical treatment of the deformity by simultaneous soft tissue release, VDRSO and PPO. All anterior–posterior (AP) radiographs of the pelvis were reviewed and Reimers migration percentage (MP) and acetabular angle (AA) were measured.

Results

In total, 54 children and adolescents (34 boys, 20 girls) with CP GMFCS level IV and V were treated during study period: 38 (70.4%) classified GMFCS level IV and 16 (29.6%) classified GMFCS level V. A total of 64 consecutive hips underwent simultaneous PPO associated with VDRSO. Overall, at the time of chart and radiograph review, mean age was 9.1 ± 3.3 years (range 4–16.5) and mean follow-up was 43.9 ± 19.5 months (range 3–72). Mean migration percentage improved from 66.8 ± 19.8% (range 33–100) preoperatively to 8.1 ± 16.5% (range 0–70) at last follow-up. Mean acetabular angle improved from 32.7° ± 7.1° (range 20–50) preoperatively to 14° ± 6.7° (range 0–27) at last follow-up. Only one case of bone graft dislodgment was observed. We did not observe any cases of avascular necrosis of the femoral head. All operated hips were pain free at the time of last follow-up.

Conclusion

PPO through a less invasive surgical approach offers a valuable alternative to standard techniques as it gives similar outcome but with less muscle stripping and less time in surgery.

Level of evidence

III.

     

SARS-CoV-2 infection in patients with chronic lymphocytic leukemia: The Italian Hematology Alliance on COVID-19 cohort

COVID-19, the disease caused by SARS-CoV-2, is still afflicting thousands of people across the globe. Few studies on COVID-19 in chronic lymphocytic leukemia (CLL) are available. Here, we analyzed data from the CLL cohort of the Italian Hematology Alliance on COVID-19 (NCT04352556), which included 256 CLL patients enrolled between 25 February 2020 and 1 February 2021. Median age was 70 years (range 38–94) with male preponderance (60.1%). Approximately half of patients (n = 127) had received at least one line of therapy for CLL, including 108 (83.7%) who were on active treatment at the time of COVID-19 or received their last therapy within 12 months. Most patients (230/256, 89.9%) were symptomatic at COVID-19 diagnosis and the majority required hospitalization (n = 176). Overall, after a median follow-up of 42 days (IQR 24–96), case fatality rate was 30.1%, and it was 37.5% and 24.4% in the first (25 February 2020–22 June 2020) and second wave (23 June 2020–1 February 2021), respectively (p = 0.03). At multivariate analysis, male sex (HR 1.82, 95% CI 1.03–3.24, p = 0.04), age over than 70 years (HR 2.23, 95% CI 1.23–4.05, p = 0.01), any treatment for CLL given in the last 12 months (HR 1.72, 95% CI 1.04–2.84, p = 0.04) and COVID-19 severity (severe: HR 5.66, 95% CI 2.62–12.33, p < 0.0001; critical: HR 15.99, 95% CI 6.93–36.90, p < 0.0001) were independently associated with poor survival. In summary, we report a dismal COVID-related outcome in a significant fraction of CLL patients, that can be nicely predicted by clinical parameters.     

Parenteral Nutrition Is One of the Most Significant Risk Factors for Nosocomial Infections in a Pediatric Cardiac Intensive Care Unit

Background: Nosocomial infections (NIs) are associated with significant morbidity and mortality and increased healthcare costs. We aimed to assess the NI epidemiology and associated risk factors in a pediatric cardiac intensive care unit (PCICU). Materials and Methods: Prospective observational study on 1106 patients admitted to a PCICU from January 1, 2012, to October 31, 2013. NIs were defined and recorded weekly by a multidisciplinary team. Independent risk factors for NIs were assessed by logistic regression analysis in the overall cohort, in cardiac surgical patients, and in those who had cardiopulmonary bypass (CPB). Results: Ninety‐two patients (8.3%) had NIs. Overall mortality was 2% but 8.3% in children with NIs (P < .001). The most frequent NIs were pneumonia (19.6%), bacteremia of unknown origin (16.3%), and catheter‐associated bloodstream infection (14.1%) caused mainly by Staphylococcus aureus and Pseudomonas aeruginosa. In the overall cohort, independent risk factors for NIs were number of days of parenteral nutrition (PN), days of invasive and noninvasive ventilation, ward before PCICU admission, and days of PCICU stay; in the cardiac surgical patients, the risk factors were days of PN and days of invasive and noninvasive ventilation; in children who had undergone CPB, the risk factors for NIs were days of PN, delayed sternal closure, reintervention, length of CPB, younger age, and days of invasive ventilation. Conclusion: Mortality was significantly higher in patients with NIs. The use of PN was one of the most significant predictors for NIs in the overall cohort of PCICU patients, cardiac surgical patients, and those who required CPB.     

Improvement of Inflammation and Pain after Three Months’ Exclusion Diet in Rheumatoid Arthritis Patients

Introduction: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease affecting the synovial joints and causing severe disability. Environmental and lifestyle factors, including diet, have been proposed to play a role in the onset and severity of RA. Dietary manipulation may help to manage the symptoms of RA by lowering inflammation and potentially decreasing pain. Methods: In 40 patients with long-standing RA with stable symptoms and treated with conventional (c-) and biological (b-) disease modifying anti-rheumatic drugs (DMARDs), the effect of a 3-month diet avoiding meat, gluten, and lactose (and all dairy products; privative diet) was evaluated in comparison with a control balanced diet including those foods. Both diets were designed to reduce weight since all patients were overweight or obese. Patients were randomly assigned to one of the diets, and RA was clinically assessed at Time 0 (T0), through the Visual Analogue Scale (VAS), for pain, and the Disease Activity Score of 28 joints (DAS 28) for RA activity. Patients were also administered the Short Form Health survey (SF-36) and the Health Assessment Questionnaire (HAQ). At T0, a blood sample was collected for laboratory tests and adipokines measurements, and anthropometric measurements were compared. These evaluations were repeated at the end of the 3 months’ dietary regimens. Results: A significant decrease in VAS and the improvement of the overall state of physical and mental health, assessed through SF-36, was observed in patients assigned to the privative diet. Both dietary regimens resulted in the improvement of quality of life compared to baseline values; however, the change was significant only for the privative diet. With either diet, patients showed significant decreases in body weight and body mass index, with a reduction in waist and hips circumference and lower basal glucose and circulating leptin levels. A privative diet was also able to significantly reduce systolic (p = 0.003) and diastolic (p = 0.025) arterial pressure. The number of circulating leukocytes and neutrophils, and the level of hs-C-Reactive Protein also decreased after 3 months of the meat-, lactose-, and gluten-free diet. Conclusions: Our results suggest that a privative diet can result in a better control of inflammation in RA patients under stable optimized drug treatment.     

The <Superscript>68</Superscript>Ga/<Superscript>177</Superscript>Lu theragnostic concept in PSMA targeting of castration-resistant prostate cancer: correlation of SUV<Subscript>max</Subscript> values and absorbed dose estimates

Introduction

A targeted theragnostic approach based on increased expression of prostate-specific membrane antigen (PSMA) on PC cells is an attractive treatment option for patients with metastatic castration-resistant prostate cancer (mCRPC).

Methods

Ten consecutive mCRPC patients were selected for ¹⁷⁷Lu-PSMA617 therapy on the basis of PSMA-targeted ⁶⁸Ga-PSMA-HBED-CC PET/CT diagnosis showing extensive and progressive tumour load. Following dosimetry along with the first therapy cycle restaging (⁶⁸Ga-PSMA-HBED-CC and ¹⁸F-NaF PET/CT) was performed after 2 and 3 therapy cycles (each 6.1?±?0.3 GBq, range 5.4–6.5 GBq) given intravenously over 30 minutes, 9?±?1 weeks apart. PET/CT scans were compared to ¹⁷⁷Lu-PSMA617 24-hour whole-body scans and contrast-enhanced dual-phase CT. Detailed comparison of SUVmax values and absorbed tumour doses was performed.

Results

¹⁷⁷Lu-PSMA617 dosimetry indicated high tumour doses for skeletal (3.4?±?1.9 Gy/GBq; range 1.1–7.2 Gy/GBq), lymph node (2.6?±?0.4 Gy/GBq; range 2.3–2.9 Gy/GBq) as well as liver (2.4?±?0.8 Gy/GBq; range 1.7–3.3 Gy/GBq) metastases whereas the dose for tissues/organs was acceptable in all patients for an intention-to-treat activity of 18?±?0.3 GBq. Three patients showed partial remission, three mixed response, one stable and three progressive disease. Decreased ¹⁷⁷Lu-PSMA617 and ⁶⁸Ga-PSMA-HBED-CC uptake (mean SUVmax values 20.2 before and 15.0 after 2 cycles and 11.5 after 3 cycles, p?<?0.05) was found in 41/54 skeletal lesions, 12/13 lymph node metastases, 3/5 visceral metastases and 4/4 primary PC lesions.

Conclusion

Due to substantial individual variance, dosimetry is mandatory for a patient-specific approach following ¹⁷⁷Lu-PSMA617 therapy. Higher activities and/or shorter treatment intervals should be applied in a larger prospective study.

     

Biotribology of artificial hip joints

Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion.