Dendritic spine loss and synaptic alterations in Alzheimer's disease

Dendritic spines are tiny protrusions along dendrites, which constitute major postsynaptic sites for excitatory synaptic transmission. These spines are highly motile and can undergo remodeling even in the adult nervous system. Spine remodeling and the formation of new synapses are activity-dependent processes that provide a basis for memory formation. A loss or alteration of these structures has been described in patients with neurodegenerative disorders such as Alzheimer's disease (AD), and in mouse models for these disorders. Such alteration is thought to be responsible for cognitive deficits long before or even in the absence of neuronal loss, but the underlying mechanisms are poorly understood. This review will describe recent findings and discoveries on the loss or alteration of dendritic spines induced by the amyloid beta (Abeta) peptide in the context of AD

Single Lymphaticovenular Anastomosis for Early-Stage Lower Extremity Lymphedema Treated by the Superior-Edge-of-the-Knee Incision Method

Background:. Surgical treatment of lower extremity lymphedema (LEL) remains challenging. Application of the superior-edge-of-the-knee incision method for lymphaticovenular anastomosis (LVA) is reported to have a strong therapeutic effect in patients with LEL because lymph-to-venous flow at the anastomosis is enhanced by knee joint movement during normal walking. We investigated whether a single LVA created by this method is adequate for early LEL. Methods:. The study involved 10 patients with LEL characterized by stage 2 or 3 leg dermal backflow and treated by a single LVA at the thigh via the superior-edge-of-the-knee incision method. The lymphatic vessel and direction of flow were assessed intraoperatively, and reduction in lymphedema volume was assessed postoperatively. Results:. Use of our incision method yielded a single anastomosis in all patients with stage 2 leg dermal backflow and in all patients with stage 3 leg dermal backflow. The lymphatic vessel was 0.65 ± 0.08 mm in diameter (0.65 ± 0.09 and 0.65 ± 0.09 mm, respectively; P = 1.000). No venous reflux occurred in any patient. Mean follow-up was 7.70 ± 3.30 months (9.60 ± 3.29 and 5.80 ± 2.17 months, respectively; P = 0.068). Mean reduction in the LEL index was 20.160 ± 9.892 (22.651 ± 12.272 and 17.668 ± 7.353, respectively; P = 0.462). Conclusion:. A single LVA created by the superior-edge-of-the-knee incision method can be expected to have a strong therapeutic effect in patients with stage 2 or 3 leg dermal backflow

Use of the Distal Facial Artery (Angular Artery) for Supermicrosurgical Midface Reconstruction

Background:. In free-flap reconstruction of the midface, options for the recipient artery are quite limited; the superficial temporal artery and the facial artery are the most commonly used arteries. We report our approach for the use of the angular artery (the terminal branch of the facial artery) as the recipient artery in free-flap reconstruction of the midface. Methods:. Nine patients with midface defects underwent free-flap reconstructions using the angular artery as the recipient artery. Identification and marking of the facial artery were performed preoperatively using handheld Doppler ultrasound. The angular artery was located through an incision made on the side of the nose. When present, a vena comitans of the facial artery or any subcutaneous vein in the vicinity of the defect was used as the recipient vein. In other cases, the facial vein in the submandibular region was chosen as the recipient vein, using a vein graft. Results:. The average diameter of the angular artery was 0.9 mm (range, 0.7–1.0 mm). In all cases, arterial anastomosis was performed in an end-to-end fashion, and flaps survived completely. In 4 cases, a vein graft was used to bridge the pedicle vein and the facial vein. Conclusions:. Although supermicrosurgical skills may be required for its anastomosis, the angular artery is an anatomically consistent artery, which is suitable for use as the recipient artery in free-flap reconstruction of the midface. Use of the angular artery as the recipient artery allows shorter flap pedicles and decreases the number of vein grafts necessary

Ultra High-frequency Ultrasonographic Imaging with 70 MHz Scanner for Visualization of the Lymphatic Vessels

Background:. Identification and localization of functional lymphatic vessels are important for lymphaticovenular anastomosis. Conventional high-frequency ultrasound (CHFUS) has been reported to be useful for them, but it has some disadvantages. In this article, we present new capabilities of ultra high-frequency ultrasound (UHFUS) for imaging of the lymphatic vessels, which may overcome the weakness of CHFUS. Methods:. Thirty unaffected extremities in 30 unilateral secondary lymphedema patients (13 upper limbs and 17 lower limbs) were examined. Identification of the lymphatic vessels using UHFUS and CHFUS were performed at 3 sites in each unaffected extremity. Number and diameter of the detected lymphatic vessels were compared between UHFUS and CHFUS groups. At the same time, new characteristics of the lymphatic vessels seen with UHFUS were investigated. Results:. One hundred sixty-nine lymphatic vessels were detected with UHFUS, and 118 lymphatic vessels with CHFUS. The number of lymphatic vessels found in upper and lower extremities was significantly larger with UHFUS than with CHFUS. The diameter of lymphatic vessels found in upper and lower extremities was significantly smaller with UHFUS than with CHFUS. All lymphatic vessels that were detected in UFHUS were less likely to collapse when the transducer was against the skin of the examined sites. Conclusions:. Detection rate of the lymphatic vessels in nonlymphedematous extremities with UHFUS was higher than that with CHFUS. UHFUS provides images with extremely high resolution, demonstrating new characteristics of the lymphatic vessels

Feasibility of Bone Perfusion Evaluation in Cadavers Using Indocyanine Green Fluorescence Angiography

Summary:. Bone perfusion evaluation methods in cadaver studies have yet to be established. The aim of this report was to introduce and validate the feasibility of indocyanine green (ICG) fluorescence angiography for evaluation of bone perfusion in the femoral medial condyle in cadavers. In 4 fresh nonembalmed cadavers (2 female), the descending genicular artery was dissected and carefully cannulated bilaterally. A 10 mL solution containing 5 mL ICG solution and 5 mL methylene blue solution was injected into the descending genicular artery. After the injection, the medial femoral condyle was cut with an oscillating saw. A photograph was taken of the cut ends of the bone. The cut ends of the bones were observed using a near-infrared camera. Images corresponding to the previously taken photographs of the cut ends were captured for comparative analysis. After injection of methylene blue and ICG, the blue dye could be seen in the periosteum in all specimens, but not inside the cortex or the cancellous region of the bone. When observed with ICG fluorescence angiography, however, the cancellous region was highlighted through small perforators penetrating the periosteum. Perfusion inside the medial femoral condyle in cadavers was confirmed using ICG fluorescence angiography. Our method can be especially beneficial in confirming the bone perfusion of a new bone flap based on a particular artery, both in cadavers as well as in patients, because ICG can be injected into specific arteries

A Combined Therapy Using Encircling Pulmonary Vein Isolation and Supplemental Segmental Ostial Isolation for the Treatment of Atrial Fibrillation

Electrical isolation of the pulmonary veins (PV) has become a curative treatment for patients with atrial fibrillation (AF). Recently, there have been many reports that circumferential PV isolation (CPI) on the atrial side has a better outcome than segmental ostial PV isolation (SOPI). However, reports on the combination of CPI using electoroanatomic mapping and SOPI using a circular mapping catheter have been few. The aim of the present study was to investigate the efficacy and safety of a combined therapy using CPI and supplemental SOPI for the treatment of AF. We performed CPI in 120 patients with drugrefractory AF. In 27 of those patients CPI resulted in a disconnection between the left atrium (LA) and PVs. In the remaining patients, supplemental SOPI completed the LA-PV disconnection. After an average follow-up period of 10.4 months, 81.7%, 90.5% and 71.4% of the patients with paroxysmal, persistent and chronic AF, respectively, have been free of AF. In 14.1% of the patients with paroxysmal AF, a greatly reduced frequency and/or duration of the episodes of AF were observed after the ablation. No fatal complications were encountered. The present results suggest that the combination of CPI and supplemental SOPI is efficient and safe for the treatment of AF