FEM assisted evaluation of PMMA and Ti6Al4V as materials for cranioplasty resulting mechanical behaviour and the neurocranial protection

Recent advances in Computer Aided Design and Manufacturing techniques (CAD/CAM) have facilitated the rapid and precise construction of customized implants used for craniofacial reconstruction. Data of the patients' trauma, acquired through Computer Topographies (CT), provide sufficient information with regard to the defect contour profile, thus allowing a thorough preoperative evaluation whilst ensuring excellent implant precision. During the selection, however, of a suitable implant material for the specific trauma, the mechanical aspects of the implant have to be considered. This investigation aims to assess the mechanical strength, the shock resistance and the critical deflection of cranial implants manufactured with two commonly used materials, Polymethylmethacrylate (PMMA) and Ti6Al4V. Even though the strength properties of Ti-alloys are far superior to those of PMMA, there are several aspects that may act in advantage of PMMA, e.g., it is known that discontinuities in the elastic modulus of adjoined parts (bone-implant) lead to bone resorption thus loosening the fixation of the implant over time.The implant design and fixation was the same in both cases allowing a direct comparison of the implant behavior for various loads. Finite Element Methods (FEM) assisted procedures were employed, providing a valuable insight to the neurocranial protection granted by these implants.     

Left ventricular mass in normotensive,prehypertensive and hypertensive children and adolescents

The purpose of this study was to investigate differences in left ventricular mass index (LVMI) and the prevalence of left ventricular hypertrophy (LVH) in children and adolescents classified as normotensives, prehypertensives and hypertensives by ambulatory blood pressure (BP) levels. A total of 124 consecutive children and adolescents aged 5 to 18 years were analysed. Patients underwent 24 h ambulatory blood pressure monitoring (ABPM) and echocardiography. Hypertensive and prehypertensive subjects had significantly higher LVMI than normotensives (36.8 ± 8.4 g/m^2.7 and 34.1 ± 3.4 g/m^2.7 vs. 29.5 ± 8.3 g/m^2.7, P < 0.01 and P < 0.05, respectively). In multivariate analysis predictors for LVMI were body mass index (BMI) z score and hypertension (R-squared = 0.31). LVMI values in hypertensive subjects were significantly higher than those of normotensives even after adjustment for age, sex and BMI z score. The prevalence of LVH was significantly higher in the prehypertensive compared to normotensive subjects, and was equal to that of the hypertensive subjects. Hypertension and prehypertension in children and adolescents were associated with pathologically elevated LVMI values. If confirmed in a larger group prehypertensive children may be at risk for target organ damage similar to the condition of established hypertension.     

Myristoylated adenylate kinase-2 of Plasmodium falciparum forms a heterodimer with myristoyltransferase

Adenylate kinases (AK; ATP+AMP<-->2 ADP; E.C. 2.7.4.3.) are enzymes essentially involved in energy metabolism and macromolecular biosynthesis. As we reported previously, the malarial parasite Plasmodium falciparum possesses one genuine AK and one GTP-AMP phosphotransferase. Analysis of the P. falciparum genome suggested the presence of one additional adenylate kinase, which we designated AK2. Recombinantly produced AK2 was found to be a monomeric protein of 33 kDa showing a specific activity of 10 U/mg with ATP and AMP as a substrate pair and to interact with the AK-specific inhibitor P(1),P(5)-(diadenosine-5')-pentaphosphate (IC(50)=200 nM). At its N-terminus AK2 carries a predicted myristoylation sequence. This sequence is only present in AK2 of P. falciparum causing the severe tropical malaria and not in other malarial parasites. We heterologously coexpressed AK2 and P. falciparum N-myristoyltransferase (NMT) in the presence of myristate in Escherichia coli. As demonstrated by protein purification and mass spectrometry, AK2 is indeed myristoylated under catalysis of the parasites' transferase. The modification significantly enhances the stability of the kinase. Furthermore, AK2 and NMT were shown to interact strongly with each other forming a heterodimeric protein in vitro. To our knowledge this is the first direct evidence that P. falciparum NMT myristoylates an intact malarial protein.     

Lipoprotein profile,glycemic control and physical fitness after strength and aerobic training in post-menopausal women with type 2 diabetes

We studied the effects on blood lipids and physical fitness after a training program that combined strength and aerobic exercise in postmenopausal women with type 2 diabetes. Ten patients (55.0 ± 5.2 years) followed four exercise sessions per week, two strength and two aerobic, and ten (59.4 ± 3.2 years) served as a control group. Lipid profile, glycated hemoglobin (HbA_1c), HOMA2 index, exercise stress and muscular testing were assessed at the beginning and after 16 weeks of training program. Exercise training increased significantly HDL-C (17.2%; P < 0.001) and decreased triglycerides (18.9%), HbA_1c (15.0%), fasting plasma glucose (5.4%), insulin resistance (HOMA2 25.2%) and resting blood pressure (P < 0.01). After 16 weeks of training, exercise time (17.8%) and muscular strength increased significantly (P < 0.001). The results indicated that a combined strength and aerobic training program could induce positive adaptations on lipid profile, glycemic control, insulin resistance, cardiovascular function, and physical fitness in post-menopausal women with type 2 diabetes. An erratum to this article can be found at     

The effect of exercise on adrenocortical responsiveness of patients with chronic low back pain, controlled for psychological strain

OBJECTIVE: To investigate the effects of high-intensity aerobic exercise on adrenocortical responsiveness and on standard outcome measures in patients with chronic low back pain. DESIGN: Controlled clinical trial. SETTING: Physical therapy department of a university general hospital. SUBJECTS: Sixty-four patients with chronic low back pain were randomly allocated into positive and negative suppression test groups and assigned to exercise protocol. INTERVENTIONS: Subjects in the positive and negative dexamethasone suppression test groups received a 12-week high-intensity aerobic exercise programme. MAIN OUTCOME MEASURES: Dexamethasone suppression test as an index of adrenocortical responsiveness, pain measured with the McGill Pain Questionnaire, functional status measured with the Roland Morris Disability Questionnaire, and psychological strain measured with the Hospital Anxiety and Depression Scale. RESULTS: Data analysis in the positive group identified a significant reduction of pain by 30% (t(30) = 11.2, P<0.001), a recovery of the lost functioning by 34% (t(30) = 19.7, P<0.001), a reduction of anxiety/depression by 25% (t(30) = 10.2, P<0.001), and a change in adrenocortical responsiveness by 40% (t(30) = 14.1, P<0.001). In the dexamethasone suppression test negative group, data analysis identified a significant reduction of pain by 8% (t(31) = 4.2, P<0.001), a recovery of lost functioning by 10% (t(31) = 4.8, P<0.001), a reduction of anxiety/depression by 11% (t(31) = 5.0, P<0.001), and no change in adrenocortical responsiveness (t(31) = 1.2, P=0.22). In univariate analysis between-subject differences were significant for dexamethasone suppression test (F(61) = 163, P<0.001), and for anxiety/depression (F(61) = 21.3, P<0.001). CONCLUSION: Exercise alleviated pain, functional disability and anxiety/depression, also improved adrenocortical responsiveness in patients with chronic low back pain with dexamethasone suppression test positive values.     

The investigation of syncope

Patients with syncope are usually referred to either neurology or cardiology clinics, yet the facilities for detailed syncope investigation are mostly in cardiac units. The diagnosis rests principally upon the history, but investigations may be required to support the clinical diagnosis. Close collaboration between the epilepsy clinician and a cardiologist is essential for effective investigation and safe management of syncope. It is frequently misdiagnosed and often erroneously treated as epilepsy. Furthermore, it is potentially a marker of sudden death when associated with certain cardiac disorders. Here we review the main syncope types and explore diagnostic approaches.     

Urgent endovascular stent-graft placement for traumatic penetrating subclavian artery injuries

Penetrating injuries may infrequently cause pseudoaneurysms, lacerations and arteriovenous fistulas involving the subclavian artery. These injuries present with life-threatening bleedings, associated regional injuries and critical limb ischemia and although surgery has been considered the treatment of choice, subclavian injuries pose a real surgical challenge. We prospectively examined data of six patients presenting with penetrating subclavian artery injuries that were treated by urgent endovascular stent-graft placements. All stent-grafts were deployed successfully achieving complete exclusion of the pseudoaneurysm, control of bleeding and reconstruction of the injured artery. No procedural complications, stent thrombosis or stent infections occurred during hospitalization. One patient developed stenosis at 7 months, which required angioplasty. The series mean clinical and ultrasound-CTA follow-up is 38+/-19.7 months (range 11-60 months) and 28+/-19.1 months (range 6-58 months), respectively. This series shows the feasibility of endovascular repair by means of stent-grafts for selected patients with acute penetrating injuries of the subclavian arteries. This approach proved to be safe and effective in restoring the arterial lumen and patency, excluding the pseudoaneurysms and controlling the bleeding caused by subclavian lacerations. Mid-term follow-up on stent-graft patency rates are encouraging.     

Endovascular treatment of congenital carotid-cavernous fistulas in infancy

Congenital dural arteriovenous fistulas have been infrequently described in pediatric population and they generally affect the transverse, sigmoid, straight or sagittal sinuses. Congenital carotid-cavernous fistulas in infancy are considered very rare and to our knowledge, only four cases have been reported in literature. Currently, the preferred treatment is endovascular embolization through trans-arterial route. We review the literature on congenital carotid cavernous fistulas in infancy focusing on the endovascular treatment of this rare entity and present our experience.     

Discovery of potent, selective, orally active, nonpeptide inhibitors of human mast cell chymase

A series of beta-carboxamido-phosphon(in)ic acids (2) was identified as a new structural motif for obtaining potent inhibitors of human mast cell chymase. For example, 1-naphthyl derivative 5f had an IC50 value of 29 nM and (E)-styryl derivative 6g had an IC50 value of 3.5 nM. An X-ray structure for 5f.chymase revealed key interactions within the enzyme active site. Compound 5f was selective for inhibiting chymase versus eight serine proteases. Compound 6h was orally bioavailable in rats (F=39%), and orally efficacious in a hamster model of inflammation.