Neurocutaneous flap of the anteromedial aspect of the thigh with a distal pedicle. Anatomical study and clinical application

The authors report an anatomic study of the vascularization of the medial aspect of the thigh on 21 cadaveric dissections with injection. They describe a neuro-cutaneous medial thigh flap, with a distal pedicle, vascularised by proximal branches of the saphenous artery (branch from the descending genicular artery). This flap includes the medial femoral cutaneous nerve, which runs with a supra-aponeurotic vascular network. The anatomic variants and harvesting technique of this flap are described. Our clinical experience is based on 3 patients operated between 1996 and 1998, for coverage of an amputation stump. The results were excellent in all cases with a follow-up of 6 months to 3 years. The good quality of this skin coverage allows satisfactory adaptation of the leg prosthesis in our cases.     

Turn-on switch in parathyroid hormone receptor by a two-step parathyroid hormone binding mechanism

Parathyroid hormone (PTH) and its related receptor (PTHR) are essential regulators of calcium homeostasis and bone physiology. PTH activates PTHR by interacting with a ligand-binding site localized within the N-terminal extracellular domain (the N-domain) and the domain comprising the seven transmembrane helices and the connecting extracellular loops (the J-domain). PTH binding triggers a conformational switch in the receptor, leading to receptor activation and subsequent cellular responses. The process of receptor activation occurs rapidly, within approximately 1 s, but the binding event preceding receptor activation is not understood. By recording FRET between tetramethyl-rhodamine in PTH(1-34) and GFP in the N-domain of the receptor, we measured the binding event in real time in living cells. We show that the association time course between PTH(1-34) and PTHR involves a two-step binding process where the agonist initially binds the receptor with a fast time constant (tau approximately 140 ms) and then with slower kinetics (tau approximately 1 s). The fast and slow phases were assigned to hormone association to the receptor N- and J domains, respectively. Our data indicate that the slow binding step to the J-domain coincides with a conformational switch in the receptor, also monitored by FRET between the enhanced cyan fluorescent protein and the enhanced yellow fluorescent protein in the PTHR sensor, PTHR enhanced cyan fluorescent protein/enhanced yellow fluorescent protein (PTHR(CFP/YFP)). These data suggest that the conformational change that switches the receptor into its active state proceeds in a sequential manner, with the first rapid binding step event preceding receptor activation by PTH(1-34).     

Kv4.3 Channel Dysfunction Contributes to Trigeminal Neuropathic Pain Manifested with Orofacial Cold Hypersensitivity in Rats

Trigeminal neuropathic pain is the most debilitating pain disorder but current treatments including opiates are not effective. A common symptom of trigeminal neuropathic pain is cold allodynia/hyperalgesia or cold hypersensitivity in orofacial area, a region where exposure to cooling temperatures are inevitable in daily life. Mechanisms underlying trigeminal neuropathic pain manifested with cold hypersensitivity are not fully understood. In this study, we investigated trigeminal neuropathic pain in male rats following infraorbital nerve chronic constrictive injury (ION-CCI). Assessed by the orofacial operant behavioral test, ION-CCI animals displayed orofacial cold hypersensitivity. The cold hypersensitivity was associated with the hyperexcitability of small-sized trigeminal ganglion (TG) neurons that innervated orofacial regions. Furthermore, ION-CCI resulted in a reduction of A-type voltage-gated K⁺ currents (IA currents) in these TG neurons. We further showed that these small-sized TG neurons expressed Kv4.3 voltage-gated K⁺ channels, and Kv4.3 expression in these cells was significantly downregulated following ION-CCI. Pharmacological inhibition of Kv4.3 channels with phrixotoxin-2 inhibited IA-currents in these TG neurons and induced orofacial cold hypersensitivity. On the other hand, pharmacological potentiation of Kv4.3 channels amplified IA currents in these TG neurons and alleviated orofacial cold hypersensitivity in ION-CCI rats. Collectively, Kv4.3 downregulation in nociceptive trigeminal afferent fibers may contribute to peripheral cold hypersensitivity following trigeminal nerve injury, and Kv4.3 activators may be clinically useful to alleviate trigeminal neuropathic pain.SIGNIFICANCE STATEMENT Trigeminal neuropathic pain, the most debilitating pain disorder, is often triggered and exacerbated by cooling temperatures. Here, we created infraorbital nerve chronic constrictive injury (ION-CCI) in rats, an animal model of trigeminal neuropathic pain to show that dysfunction of Kv4.3 voltage-gated K⁺ channels in nociceptive-like trigeminal ganglion (TG) neurons underlies the trigeminal neuropathic pain manifested with cold hypersensitivity in orofacial regions. Furthermore, we demonstrate that pharmacological potentiation of Kv4.3 channels can alleviate orofacial cold hypersensitivity in ION-CCI rats. Our results may have clinical implications in trigeminal neuropathic pain in human patients, and Kv4.3 channels may be an effective therapeutic target for this devastating pain disorder.     

Les lésions traumatiques de l’aorte descendante en dehors de l’isthme : particularités diagnostiques et thérapeutiques

Lesions involving the descending thoracic aorta apart from isthmus are rare and less known by anesthetists. We report the clinical course of two severely injured patients who sustained a thoracic aortic rupture in whom favorable outcome was achieved with endovascular treatment. Mechanisms, diagnosis and therapeutics aspects of these rare lesions are discussed according to literature.     

Assessment of Technological Capabilities for Forming Al-C-B System Coatings on Steel Surfaces by Electrospark Alloying Method

In this paper, the possibility of applying the electrospark alloying (ESA) method to obtain boron-containing coatings characterised by increased hardness and wear resistance is considered. A new method for producing such coatings is proposed. The method consists in applying grease containing aluminium powder and amorphous boron to the surface to be treated and subsequently processing the obtained surface using the ESA method by a graphite electrode. The microstructural analysis of the Al-C-B coatings on steel C40 showed that the surface layer consists of several zones, the number and parameters of which are determined by the energy conditions of the ESA process. Durametric studies showed that with an increase in the discharge energy influence, the microhardness values of both the upper strengthened layer and the diffusion zone increased to W_p = 0.13 J, Hµ = 6487 MPa, and W_p = 4.9 J, Hµ = 12350 MPa, respectively. The results of X-ray diffraction analysis indicate that at the discharge energies of 0.13 and 0.55 J, the phase composition of the coating is represented by solid solutions of body-centred cubic lattice (BCC) and face-centred cubic lattice (FCC). The coatings obtained at W_p = 4.9 J were characterised by the presence of intermetallics Fe₄Al₁₃ and borocementite Fe₃ (CB) in addition to the solid solutions. The X-ray spectral analysis of the obtained coatings indicated that during the electrospark alloying process, the surface layers were saturated with aluminium, boron, and carbon. With increasing discharge energy, the diffusion zone increases; during the ESA process with the use of the discharge energy of 0.13 J for steel C40, the diffusion zone is 10–15 μm. When replacing a substrate made of steel C40 with the same one material but of steel C22, an increase in the thickness of the surface layer accompanied by a slight decrease in microhardness is observed as a result of processing with the use of the ESA method. There were simulated phase portraits of the Al-C-B coatings. It is shown that near the stationary points in the phase portraits, one can see either a slowing down of the evolution or a spiral twisting of the diffusion-process particle.     

Real-Time PCR Assay for Rapid Detection of Epidemiologically and Clinically Significant Mycobacterium tuberculosis Beijing Genotype Isolates

Mycobacterium tuberculosis Beijing genotype strains are rapidly disseminating, frequently hypervirulent, and multidrug resistant. Here, we describe a method for their rapid detection by real-time PCR that targets the specific IS6110 insertion in the dnaA-dnaN genome region. The method was evaluated with a geographically and genetically diverse collection representing areas in East Asia and the former Soviet Union in which the Beijing genotype is endemic and epidemic (i.e., major foci of its global propagation) and with clinical specimens.     

Pancreatic adenocarcinoma: Outstanding problems

Pancreatic adenocarcinoma remains the fourth leading cause of cancer-related death and is one of the most aggressive malignant tumors with an overall 5-year survival rate of less than 4%.Surgical resection remains the only potentially curative treatment but is only possible for 15%-20% of patients with pancreatic adenocarcinoma.About 40% of patients have locally advanced nonresectable disease.In the past,determination of pancreatic cancer resectability was made at surgical exploration.The development of modern imaging techniques has allowed preoperative staging of patients.Institutions disagree about the criteria used to classify patients.Vascular invasion in pancreatic cancers plays a very important role in determining treatment and prognosis.There is no evidence-based consensus on the optimal preoperative imaging assessment of patients with suspected pancreatic cancer and a unified definition ofborderline resectable pancreatic cancer is also lacking.Thus,there is much room for improvement in all aspects of treatment for pancreatic cancer.Multi-detector computed tomography has been widely accepted as the imaging technique of choice for diagnosing and staging pancreatic cancer.With improved surgical techniques and advanced perioperative management,vascular resection and reconstruction are performed more frequently;patients thought once to be unresectable are undergoing radical surgery.However,when attempting heroic surgery,a realistic approach concerning the patient’s age and health status,probability of recovery after surgery,perioperative morbidity and mortality and life quality after tumor resection is necessary.     

Optical phase modulation by natural eye movements: application to time-domain FF-OCT image retrieval

Eye movements are commonly seen as an obstacle to high-resolution ophthalmic imaging. In this context we study the natural axial movements of the in vivo human eye and show that they can be used to modulate the optical phase and retrieve tomographic images via time-domain full-field optical coherence tomography (TD-FF-OCT). This approach opens a path to a simplified ophthalmic TD-FF-OCT device, operating without the usual piezo motor-camera synchronization. The device demonstrates in vivo human corneal images under the different image retrieval schemes (2-phase and 4-phase) and different exposure times (3.5 ms, 10 ms, 20 ms). Data on eye movements, acquired with a spectral-domain OCT with axial eye tracking (180 B-scans/s), are used to study the influence of ocular motion on the probability of capturing high-signal tomographic images without phase washout. The optimal combinations of camera acquisition speed and amplitude of piezo modulation are proposed and discussed.