Multiscale analysis of Klf10's impact on the passive mechanical properties of murine skeletal muscle

Skeletal muscle is a hierarchical structure composed of multiple organizational scales. A major challenge in the biomechanical evaluation of muscle relates to the difficulty in evaluating the experimental mechanical properties at the different organizational levels of the same tissue. Indeed, the ability to integrate mechanical properties evaluated at various levels will allow for improved assessment of the entire tissue, leading to a better understanding of how changes at each level evolve over time and/or impact tissue function, especially in the case of muscle diseases. Therefore, the purpose of this study was to analyze a genetically engineered mouse model (Klf10 KO: Krüppel-Like Factor 10 knockout) with known skeletal muscle defects to compare the mechanical properties with wild-type (WT) controls at the three main muscle scales: the macroscopic (whole muscle), microscopic (fiber) and submicron (myofibril) levels. Passive mechanical tests (ramp, relaxation) were performed on two types of skeletal muscle (soleus and extensor digitorum longus (EDL)). Results of the present study revealed muscle-type specific behaviors in both genotypes only at the microscopic scale. Interestingly, loss of Klf10 expression resulted in increased passive properties in the soleus but decreased passive properties in the EDL compared to WT controls. At the submicron scale, no changes were observed between WT and Klf10 KO myofibrils for either muscle; these results demonstrate that the passive property differences observed at the microscopic scale (fiber) are not caused by sarcomere intrinsic alterations but instead must originate outside the sarcomeres, likely in the collagen-based extracellular matrix. The macroscopic scale revealed similar passive mechanical properties between WT and Klf10 KO hindlimb muscles. The present study has allowed for a better understanding of the role of Klf10 on the passive mechanical properties of skeletal muscle and has provided reference data to the literature which could be used by the community for muscle multiscale modeling.

Percutaneous infraclavicular subclavian vein catheters in paediatric cancer patients in comparison with critically ill children: a one-year experience from a Tunisian hospital

BACKGROUND

Paediatric cancer and critically ill patients frequently require central venous catheters for prolonged intravenous therapy. The aim of this study is to compare the difficulty of catheter insertion and the morbidity related to this procedure in these two populations and to investigate risk factors for complications.

METHODS

This prospective observational study was conducted at the Hedi Chaker University Hospital in Sfax, Tunisia, from July 2021 to July 2022. We included all patients aged three months to 14 years who required an infraclavicular subclavian vein catheterization. Patients were divided into two groups: Group 1 included children with malignancies; and Group 2 included critically ill paediatric patients. Then, we compared the demographic data, the difficulty of the catheterization procedure, and catheter-related complications. We also investigated risk factors for complications using a logistic regression model. The significance level was P<0.05.

RESULTS

We included 65 infants and children requiring central venous access, 28 of whom suffered from malignancies. The demographic parameters were comparable. However, the time for the procedure and the number of attempts were higher in the malignancy group with P<0.001. Central venous catheter complications were present 46.4% of the time in Group 1 compared to 21.6% in Group 2 (P=0.032). Malignancies were associated with an increased risk of complications (aOR = 2.95; 95%CI: 0.63-13.8).

CONCLUSIONS

This study showed increased difficulty and higher morbidity related to infraclavicular subclavian vein catheterization among infants and children suffering from cancer.

Early versus late removal of the I-Gel in paediatric patients with mild upper respiratory tract symptoms undergoing ambulatory ilioinguinal surgery: A prospective observational study

The optimal timing of I-Gel removal in children with mild respiratory symptoms remains controversial. Consequently, we tried to assess the impact of early versus late I-Gel removal on the incidence of perioperative respiratory adverse events among children aged one to five years undergoing ambulatory surgery under general anaesthesia with I-Gel airway ventilation. The anaesthesia protocol was the same for all patients. Children were divided into two groups according to the approach of I-Gel removal (early versus late). The incidence of perioperative respiratory adverse events after the I-Gel removal was the main outcome, and a multivariable regression was performed to investigate the implication of the I-Gel removal in perioperative respiratory adverse events. According to our study, the incidence of perioperative respiratory adverse events was not correlated to the timing of I-Gel removal. However, prolonged postoperative oxygen support can be seen when the I-Gel is removed in anaesthetized children.

Management of COVID-19-Associated Guillain-Barré Syndrome in a Full-Term Pregnant Woman: A Case Report

Guillain-Barré syndrome (GBS) can occur after viral infections. Its occurrence after COVID-19 infection in the peripartum period is a very rare co-occurrence. Therefore, there are no guidelines for the management of these patients. We report the case of a 32-year-old pregnant woman who developed COVID-19-associated GBS with aspiration pneumonia, motor weakness, and ascending paralysis at 39 weeks of gestation. Preoperative plasmatic exchange (plasmapheresis) and oxygen support were very effective and allowed for a rapid recovery within five days. Because of foetal distress during labor, the patient had a caesarean section under spinal anaesthesia with no maternal complications or adverse foetal outcomes.

Predictors of perioperative respiratory adverse events among children with upper respiratory tract infection undergoing pediatric ambulatory ilioinguinal surgery: a prospective observational research

Objectives

Anesthesia for children with an upper respiratory tract infection (URI) has an increased risk of perioperative respiratory adverse events (PRAEs) that may be predicted according to the COLDS score. The aims of this study were to evaluate the validity of the COLDS score in children undergoing ilioinguinal ambulatory surgery with mild to moderate URI and to investigate new predictors of PRAEs.

Methods

This was a prospective observational study including children aged 1–5 years with mild to moderate symptoms of URI who were proposed for ambulatory ilioinguinal surgery. The anesthesia protocol was standardized. Patients were divided into two groups according to the incidence of PRAEs. Multivariate logistic regression was performed to assess predictors for PRAEs.

Results

In this observational study, 216 children were included. The incidence of PRAEs was 21%. Predictors of PRAEs were respiratory comorbidities (adjusted OR (aOR)=6.3, 95% CI 1.19 to 33.2; p=0.003), patients postponed before 15 days (aOR=4.3, 95% CI 0.83 to 22.4; p=0.029), passive smoking (aOR=5.31, 95% CI 2.07 to 13.6; p=0.001), and COLDS score of >10 (aOR=3.7, 95% CI 0.2 to 53.4; p=0.036).

Conclusions

Even in ambulatory surgery, the COLDS score was effective in predicting the risks of PRAEs. Passive smoking and previous comorbidities were the main predictors of PRAEs in our population. It seems that children with severe URI should be postponed to receive surgery for more than 15 days.

Complications and its risk factors of percutaneous subclavian vein catheters in pediatric patients: enhancing the outcomes of a university hospital in a low-income and middle-income country

Objective

Assessing central venous catheter-related complications with regular feedback and investigating risk factors are mandatory to enhance outcomes. The aim of this study is to assess our experience in the management of pediatric subclavian vein catheters (SVCs) and to investigate the main risk factors for complications.

Methods

In this prospective observational study, we included children aged 3 months to 14 years who underwent infraclavicular subclavian vein catheterization consecutively using the anatomic landmark technique. Patients were divided into two groups: group 1 included complicated catheters and group 2 included non-complicated catheters. The management protocol was standardized for all patients. After comparing the two groups, univariate and multivariate logistic regression were used to investigate the risk factors for complications.

Results

In this study, we included 134 pediatric patients. The rate of complications was 32.8%. The main complications were central line-associated bloodstream infection (63.6%), bleeding and/or hematoma (22.7%), mechanical complications (13.6%), and vein thrombosis (13.6%). After adjustment for confounding factors, predictors of catheter-related complications were difficult insertion procedure (adjusted odds ratio (aOR)=9.4; 95% confidential interval (CI): 2.32 to 38.4), thrombocytopenia (aOR=4.43; 95% CI: 1.16 to 16.86), comorbidities (aOR=2.93; 95% CI: 0.58 to 14.7), and neutropenia (aOR=5.45; 95% CI: 2.29 to 13.0).

Conclusions

High rates of complications were associated with difficult catheter placement and patients with comorbidities and severe thrombocytopenia. To reduce catheter-related morbidity, we suggest an ultrasound-guided approach, a multidisciplinary teaching program to improve nursing skills, and the use of less invasive devices for patients with cancer.

Improvement of Broviac catheter-related outcomes after the implementation of a quality management system: A before-and-after prospective observational study

Background: Because of the high rates of Broviac catheter complications, we started an urgent quality process to reduce this morbidity. The aim is to assess the efficiency of the main actions we have taken in enhancing our practice and improving Broviac outcomes. Methods: We included all neonates and young infants requiring surgical central venous access using a Broviac tunneled catheter. We compared the catheters’ outcomes before and after the implementation of a quality program based on a nurse teaching program, patient selection, and catheter management multidisciplinary protocol. The significance threshold was set at p<0.05. Results: We included 94 patients: 51 in the protocol group and 43 in the control group. The complication rate was reduced from 60.3% to 25.5% with p=0.001. The lifetime of the catheter was improved from 11.3 ± 4.3 days to 19.1 ± 9 days with p=0.007. The catheter infection was reduced from 65.3% to 46.1% with p≤0.001. Conclusion: This quality improvement project shows the utility of a quality assurance program based on careful indications and patient selection, a nursing teaching program, and a multidisciplinary catheter management protocol, in reducing Broviac catheter-related morbidity.

Risk factors for Hickman-Broviac catheter complications: An experience from a Tunisian hospital

Background: Hickman-Broviac catheters have improved the care of young children needing frequent and prolonged venous access, but at the same times it has substantial morbidity, particularly in a resource-constrained setup. Our study aims to describe the experience of a Tunisian hospital and investigate the main risk factors for complications. Methods: In this study, we included all the neonates and infants who underwent Broviac catheter insertion in the pediatric surgery department. The patients were divided into 2 groups according to the presence of complications. We compared these two groups and univariate logistic regression analyses were used to determine the risk factors for complications. Results: Forty-three children were included in the study. The incidence of complicated catheters was 60.4%. The following factors were significantly associated with an increased risk of complications: age 6 months [OR 3.5, 95% CI: 0.6-19.3], weight 6 kg [OR 1.54, 95% CI: 0.46-5.2], emergency circumstances [OR 1.62, 95% CI: 0.8-5.4], and antibiotic-therapy as an indication for Broviac catheter insertion [OR 1.8, 95% CI: 0.5-6.2]. Conclusion: Complications seem to be more frequent in patients younger than 6 months and those with a weight of less than 6Kg. To reduce the morbidity related to the catheters, the indications should be carefully chosen.

The Effect of Freezing Time on Muscle Fiber Mechanical Properties

The purpose of this study was to investigate the effect of freezing time on the functional behavior of mouse muscle fibers. Passive mechanical tests were performed on single soleus muscle fibers from fresh (0 month) and preserved (stored at -20°C for 3, 6, 9 and 12 months) 3 month old mice. The Young's modulus and the dynamic and the static stresses were measured. A viscoelastic Hill model of 3rd order was used to fit the experimental relaxation test data. The statistical analysis corresponding to the elastic modulus of single muscle fibers did not differ when comparing fresh and stored samples for 3 and 6 months at -20 °C. From 9 months, fibers were less resistant and the mechanical properties were damaged. The primary goal of this study was to complete the gold standard process of muscle fiber preservation for subsequent mechanical property studies. We have demonstrated that muscle fibers can be stored at -20°C for up to 6 months without altering their mechanical properties.

Sperm fluorescent in situ hybridisation study of interchromosomal effect in six Tunisian carriers of reciprocal and Robertsonian translocations

Carriers of structural chromosomal anomalies, translocations and inversions are at increased risk of aneuploid gametes production. Besides the direct effect on the involved chromosomes, these rearrangements might disturb the segregation of other structurally normal chromosomes during meiosis. Such event is known as interchromosomal effect. In this study, six male carriers of translocations, four reciprocals and two Robertsonians, were investigated. In addition, seven fertile men with normal 46,XY karyotypes and normal sperm characteristics were enrolled as a control group. Spermatic fluorescent in situ hybridisation specific for chromosomes X, Y, 18, 21 and 22 was carried out. The Mann-Whitney U-test was used to compare the aneuploidy rates between patients and controls. All translocation carriers showed significantly increased frequencies of disomy of all investigated chromosomes, and diploid gametes compared with the control group (p < .05). However, disomy XY was not significantly different between controls and patients (p > .05). We have also observed a considerable interindividual variability in disomy and diploidy rates. These results confirm that the interchromosomal effect seems to exist and could contribute to higher rates of abnormal prenatal aneuploidy, resulting in a small increase in the risk of miscarriage and birth of children with congenital abnormalities and a potential reduction in fertility.

Severe scorpion envenomation: pathophysiology and the role of inflammation in multiple organ failure

Scorpion stings occur on every continent except Antarctica. The correlation between young age and severity of clinical manifestations after this envenomation is well-established. Several studies have emphasized the relevance of pro-inflammatory mediators in the pathophysiological manifestations of human scorpion envenomation. Moreover, there is a significant association between pro-inflammatory cytokine levels in the blood and the severity of scorpion envenomation. Release of these cytokines increases the severity of the visceral damage induced by the direct action of the venom and the activation of both the sympathetic and parasympathetic nervous systems.

NOBOX is a strong autosomal candidate gene in Tunisian patients with primary ovarian insufficiency

Premature ovarian insufficiency (POI) affects approximately 1% of women before the age of 40. Genetic contribution is a significant component of POI. In this context, heterozygous mutations in NOBOX, BMP15 and GDF9 have been reported. The objective of our study was to evaluate the prevalence of these genes mutations in 125 unrelated Tunisian patients diagnosed with POI. The screening of NOBOX gene revealed three missense mutations (p.Arg117Trp; p.Gly91Trp and p.Pro619Leu) in eight patients. These mutations were not found in a 200 ethnically matched women without fertility problem. The sequencing of BMP15 and GDF9 gene revealed only previously reported variants. In contrast to previous studies, the prevalence of BMP15 variations is not higher than in the control population. Conversely, 6.4% of the cases present a NOBOX mutations; this high prevalence strengthens the consideration of NOBOX gene as strong autosomal candidate for POI.

Flexible thin-film battery based on graphene-oxide embedded in solid polymer electrolyte

Enhanced safety of flexible batteries is an imperative objective due to the intimate interaction of such devices with human organs such as flexible batteries that are integrated with touch-screens or embedded in clothing or space suits. In this study, the fabrication and testing of a high performance thin-film Li-ion battery (LIB) is reported that is both flexible and relatively safer compared to the conventional electrolyte based batteries. The concept is facilitated by the use of solid polymer nanocomposite electrolyte, specifically, composed of polyethylene oxide (PEO) matrix and 1 wt% graphene oxide (GO) nanosheets. The flexible LIB exhibits a high maximum operating voltage of 4.9 V, high capacity of 0.13 mA h cm(-2) and an energy density of 4.8 mW h cm(-3). The battery is encapsulated using a simple lamination method that is economical and scalable. The laminated battery shows robust mechanical flexibility over 6000 bending cycles and excellent electrochemical performance in both flat and bent configurations. Finite element analysis (FEA) of the LIB provides critical insights into the evolution of mechanical stresses during lamination and bending.

A simplified immunohistochemical classification of skeletal muscle fibres in mouse

The classification of muscle fibres is of particular interest for the study of the skeletal muscle properties in a wide range of scientific fields, especially animal phenotyping. It is therefore important to define a reliable method for classifying fibre types. The aim of this study was to establish a simplified method for the immunohistochemical classification of fibres in mouse. To carry it out, we first tested a combination of several anti myosin heavy chain (MyHC) antibodies in order to choose a minimum number of antibodies to implement a semi-automatic classification. Then, we compared the classification of fibres to the MyHC electrophoretic pattern on the same samples. Only two anti MyHC antibodies on serial sections with the fluorescent labeling of the Laminin were necessary to classify properly fibre types in Tibialis Anterior and Soleus mouse muscles in normal physiological conditions. This classification was virtually identical to the classification realized by the electrophoretic separation of MyHC. This immuno-histochemical classification can be applied to the total area of Tibialis Anterior and Soleus mouse muscles. Thus, we provide here a useful, simple and time-efficient method for immunohistochemical classification of fibres, applicable for research in mouse.

Profil épidémiologique et complications des voies veineuses centrales en oncologie pédiatrique : à propos de 125 cas

OBJECTIVE

To report the indications and early and late catheter-related complications in a Tunisian unit of paediatric oncology.

PATIENTS AND METHODS

This prospective study has been performed in a paediatric oncology unit of the Salah Azaïz Institute between 1989 and 2005. It concerns 58 girls and 57 boys with a median age of 7.9 years(4 months to 18 years) treated for cancer disease predominantly lymphoma (22%), sarcoma (23.2%) or leukaemia (8.5%) proposed for insertion of a central venous catheter (CVC).

RESULTS

Excluding 2 insertion failures (1.6%), we placed 123 CVC (double for 10 patients), 43 (35%) exteriorised (EC) and 80 (65%) connected to an implantable site (IS). Catheters were placed in the subclavian vein in 59.2% of cases vs 32% for internal jugular vein and 8.8% for femoral vein. Early complications included 15 cases of multiple punctures (12%), 4 cases of pneumothorax (3.2%) and 6 of arterial punctures (4.8%) originating a cervical subcutaneous haematoma in 1 patient (0.8%). Late complications were represented by infection in 7 cases (5.7%). We observed 2 cases of intracardiac catheter migration due to catheter disconnection from the IS (1.6%) and 2 cases of thrombosis (1.8%). The mean life of CVC was longer for IS (305.2 days) than for EC (64.4 days).

CONCLUSION

Implantable sites are effective progress for venous access in children with cancer. They improved the quality of care in pediatric oncology.

[Hypothyroid dilated cardiomyopathy]

Most patients with dilated cardiomyopathy have a poor prognosis due to progressive and irreversible myocardial dysfunction. Rarely, is a metabolic etiology responsive to specific therapy identified. Although many studies have confirmed that thyroid hormone deficiency is associated with a reversible decrease in myocardial contractility, it has remained controversial whether hypothyroidism alone can cause a dilated cardiomyopathy and clinical heart failure. In this study, we report the case of a patient with severe hypothyroidism and a dilated cardiomyopathy complicated by heart failure, which has receded after recovery to euthyroidism with L-thyroxin therapy. This case suggests that hypothyroidism should be evoked systematically when a dilated cardiomyopathy is diagnosed.

[Hydatid pulmonary embolism. Two case reports]

Hydatid pulmonary embolism is an uncommon condition resulting from the rupture of a hydatid heart cyst or the opening of a visceral hydatid cyst (often in the liver) into the venous circulation. We report two cases of hydatid pulmonary embolism following rupture of a hydatic cyst in the right ventricle. One case progressed to chronic cor pulmonale. We examine the pathophysiological mechanisms as well as the clinical, therapeutic and evolutive aspects.

Microglial chimaerism in human xenografts to the rat brain

Neural tissue from human fetuses is currently used for intracerebral transplantation to treat patients with Parkinson's disease. The development of the human fetal tissue following grafting has been considered mostly, up to now, from the neuronal point of view in xenografts. Very little is known, in contrast, about nonneuronal, glial, or vascular cells in the grafts. Comparison of the data gathered on the development of grafted human neurons with those obtained in comparable studies using rat transplants has demonstrated species-specific features. We have therefore undertaken a series of studies dealing with nonneuronal cells in human-to-rat transplants to reveal other possible species-specificity of the human tissue. This study has, accordingly, been devoted to the immunohistochemical analysis of microglia of host and donor origins in a human to rat xenograft paradigm allowing clear distinction of the origin of the cells. Human neural tissue was transplanted as a cell suspension into the thalamus of adult rats. Amoeboid human microglia were observed in 1-, 2-, and 3-month-old transplants, but their density, already relatively low at the first stage, decreased further over time. Ramified human microglia were only occasional. In sharp contrast, host rat microglia rapidly invaded the transplant in the absence of any sign of necrosis. The rat cells exhibited first an amoeboid morphology but progressed at the later stages toward a more mature, ramified morphology. These results indicate that donor microglia are quite few in number at first and, at least, do not proliferate actively after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Puzzling biochemical thyroid profile in patients with multinodular goitre originating from a mild iodine deficient area in Tunisia

Thirty Tunisian patients with a voluminous multinodular goiter with cold nodules and inhabiting a region of mild iodine deficiency, have been studied. The 131 I fixation by the thyroid, three hours after ingestion was significatively higher than in normal population. Fourty six per cent of the patients have stable iodine urine contents less or equal to 0.39 mumol/L. Three serum concentrations were paradoxically abnormal: thyrotropin (TSH), thyroglobulin (TG) and gammaglobulin concentrations. Fourty seven per cent of the serum thyrotropin (TSH) levels were less than the normal values though the serum total triiodotyronine (TT3), tetraiodotyronine (TT4), free triiodotyronine (FT3), free tetraiodotyronine (FT4), antithyroglobulin antibodies, total protein, triglycerides and cholesterol concentrations were normal. Serum thyroglobulin (TG) rates were elevated, ranged from 2 to 10,180 ng/ml and twenty five per cent of our patients showed levels greater than 500 ng/ml. The gammaglobulin levels were greater than normal in sixty eight per cent of our patients though only 10% of our patients manifest antithyroglobulin antibodies.

[Retroplacental hematoma and uterine Doppler scan]

The authors studied uterine Doppler findings in four cases of retroplacental hematoma at 26, 30.5, 31 and 37 weeks of amenorrhea. In all cases, the diastolic index was low, and a diastolic notch was present. In three cases, the hematoma was visualised under ultrasound. The literature on the subject confirms that the velocity of the uterine circulation is always abnormal in retroplacental hematoma. This test is therefore fundamental for the detection of clinically incomplete retroplacental hematomas and for determining the pregnancy prognosis in women with a history of vascular problems. Two of our patients received treatment with acetylsalicylic acid at an early stage of a subsequent pregnancy. The uterine Doppler scans carried out during this pregnancy at the same date as during the pregnancy with retroplacental hematoma revealed normal bloodflow velocity. The infants were born at term with normal weight. Uterine Doppler ultrasound is, therefore, an essential prognosis factor for these high-risk patients. In addition, routine performance of a uterine Doppler scan at about 22 weeks of amenorrhea in women in their first pregnancy could be useful, as any abnormal finding might be the indication for preventive treatment with acetylsalicylic acid.