Power Amplifier Predistortion Using Reduced Sampling Rates in the Forward and Feedback Paths.

The feasibility of implementing digital predistortion for next-generation wireless communication is faced with a dilemma due to the ever-increasing demand for faster data rates. This causes the utilized bandwidth to increase significantly, as seen in the 5G NR standard in which bandwidths as high as 400 MHz are utilized. Hence, the development of new predistortion techniques in which the forward and feedback paths operate at lower sampling rates is of utmost importance to realize efficient and practical predistortion solutions. In this work, a novel predistortion technique is presented by which the predistortion is divided between the digital and analog domains. The predistorter is composed of a memoryless AM/AM gain function that is implementable in the analog domain, and a nonlinear model with memory effects in the digital domain to relax the sampling rate requirements on both the forward and feedback paths. Experimental validation was carried out with a 20 MHz and a 40 MHz 5G signal, and the results indicate minimal linearization degradation with a sampling rate reduction of 50% and 30%, respectively. This sampling rate reduction is concurrently applied in the digital-to-analog converter of the forward path and the analog-to-digital converter of the feedback path.

Cardiac complex II activity is enhanced by fat and mediates greater mitochondrial oxygen consumption following hypoxic re-oxygenation.

Recent evidence suggests that mitochondrial complex II is an essential mediator of myocardial ischemia-reperfusion injury. The present study aimed to investigate the effects of fatty acid supplementation or high-fat diet (HFD) on cardiac mitochondrial activity. The changes of complex I and complex II activities and mitochondrial oxygen consumption rate (OCR) following hypoxia and re-oxygenation under these conditions were studied. Our results have shown that OCR (mitochondrial activity) was significantly increased with palmitoylcarnitine supplementation in mitochondria-enriched fraction from C57BL/6 mice hearts. Mitochondrial complex I activity was unaffected by palmitoylcarnitine but complex II activity was enhanced. Re-oxygenation following 30-min hypoxia transiently increased OCR but such an effect on OCR was abolished by complex II inhibitor, malonate, but not by complex I inhibitor, rotenone, despite that complex I activity was significantly increased with re-oxygenation following hypoxia in the presence of palmitoylcarnitine. Furthermore, OCR and complex II activity were significantly increased in the mitochondria from high-fat diet mice heart compared with those of normal or low-fat diet mice. Re-oxygenation to mitochondria following 30-min hypoxia increased OCR in all three groups but significantly more in HFD. Malonate abolished re-oxygenation-induced OCR increment in all groups. Our results indicate that complex II activity and OCR are enhanced with palmitoylcarnitine or in HFD mice heart. Although re-oxygenation following hypoxia enhanced complex II and complex I activities, complex II plays an important role in increasing mitochondrial activity, which may be instrumental in myocardial injury following ischemic reperfusion.

Sex differences in the association of cutaneous melanoma incidence rates and geographic ultraviolet light exposure.

BACKGROUND: Cutaneous melanoma (CM) incidence rates continue to increase, and the reasons are unknown. Previously, we reported a unique age-specific sex difference in melanoma that suggested additional causes other than solar ultraviolet (UV) radiation. OBJECTIVE: This study attempted to understand whether and how UV radiation differentially impacts the CM incidence in men and women. METHODS: CM data and daily UV index (UVI) from 31 cancer registries were collected for association analysis. A second dataset from 42 US states was used for validation. RESULTS: There was no association between log-transformed female CM rates and levels of UVI, but there was a significant association between male rates and UVI and a significant association between overall rates and UVI. The 5-year age-specific rate-UVI association levels (represented by Pearson's coefficient ρ) increased with age in men, but age-specific ρ levels remained low and unchanged in women. The significant rate-UVI association in men and nonassociation in women was validated in a population of white residents of the United States. LIMITATIONS: Confounders, including temperature and latitude, are difficult to separate from UVI. CONCLUSIONS: Ambient UVI appears to be associated with melanoma incidence in males but not in females.

Posterolateral wall integrity in reverse oblique intertrochanteric fracture fixation: A new perspective in evaluation.

BACKGROUND: Treatment of reverse oblique fractures has the highest complication rate among proximal femur fractures. Although intramedullary nailing is the preferred treatment option, a high failure rate has been reported. Previous studies have identified several contributing factors to these failures, yet the significance of posterolateral wall integrity in ensuring postoperative stability has not been emphasized. This study aims to investigate the impact of posterolateral wall integrity on the failure rates of reverse oblique intertrochanteric fractures treated with intramedullary nails (IMN) and assess the vulnerability of certain IMN designs to these failures. METHODS: Between 2010 and 2016, 53 patients with reverse oblique fractures were analyzed to identify factors associated with IMN failure. Variables such as posterolateral wall integrity, quality of reduction, posteromedial support, and IMN design were considered as potential risk factors. Logistic regression analysis was conducted to evaluate these risk factors, with statistical significance defined as p<0.05. RESULTS: Eleven cases of implant failure were identified. Univariate statistical analysis indicated that loss of posterolateral support (p=0.002), IMN with single-screw proximal fixation (p=0.048), poor reduction quality (p=0.004), and loss of posteromedial support (p=0.040) were associated with implant failure. Multivariate analysis confirmed loss of posterolateral support (p=0.009), poor reduction quality (p=0.039), and loss of posteromedial support (p=0.020) as independent risk factors for failure. However, IMN with single proximal fixation (p=0.859) did not significantly impact fixation failure. CONCLUSION: Reverse oblique intertrochanteric fractures with compromised posterolateral support exhibit a high rate of mechanical failure when treated with IMN. Additionally, poor reduction quality and loss of posteromedial support increase the risk for failure of these fractures. An IMN design featuring dual separate proximal screw fixations could provide better stability compared to a design with a single proximal screw, thereby reducing the risk of mechanical failure.

Does simultaneous comminuted fracture of both radial ends represent a distinct fracture pattern?

BACKGROUND: Although isolated distal radius and radial head fractures are common injuries, simultaneous ipsilateral fractures are uncommon. They can range from simple undisplaced fractures at either end to severely comminuted ipsilateral proximal and distal radial fractures. Few cases have been reported with concomitant comminuted distal radius and radial head fractures, and no treatment guidelines are available. Decisions are often based on personal recommendations. The purpose of our study is to increase awareness of this injury pattern and to discuss the mechanism of injury, treatment approach, and functional outcome. METHODS: Skeletally mature patients with comminuted simultaneous ipsilateral fractures of the distal and proximal radius from 2016 to 2021 were identified and studied retrospectively. Demographic information, mechanism of injury, treatment approach, and complication rate were analyzed. Radiographic assessment for inadequacy or loss of reduction and radiographic parameters of the distal radius, including radial inclination, radial length, and palmar inclination, was performed immediately postoperatively and at the final follow-up. Clinical outcomes were determined by calculating the Visual Analog Scale (VAS) score, measuring the range of motion in both joints, and using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score at the final follow-up. RESULTS: A total of 11 patients met the inclusion criteria. All had ipsilateral Mason III radial head fractures and type C (according to the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification) intra-articular distal radius fracture. On-table radial head reconstruction and fixation with a proximal radius plate were used for radial head fractures, and osteosynthesis with an anatomic volar locking plate was used for distal radius fractures. The mean follow-up duration was 32 months (range 12-65 months). At the final follow-up, osseous union of both the radial head and distal radius was observed in all patients. The mean VAS score was 1.5 (range 0-7) at rest and 3.9 (range 0-9) with activities, while the mean QuickDASH score was 32 (range 12-65). No significant complications were recorded. CONCLUSION: Simultaneous comminuted fractures of the ipsilateral distal radius and radial head represent a distinct injury pattern, most likely resulting from high-energy trauma, such as falling from a height onto an outstretched hand. Greater emphasis should be placed on clinical examination and radiological imaging of the elbow in cases of wrist injuries and vice versa. Treatment involving on-table reconstruction of the radial head and open reduction and internal fixation with a volar plate can lead to good radiological and functional outcomes.

Correlation of anterior chest wall anomalies and spinal deformities: a comprehensive descriptive study.

PURPOSE: To investigate the association and evaluate the characteristics between different types of anterior chest wall and spinal deformities. METHODS: A total of 548 patients with anterior chest wall deformities were included in this study. Clinical and radiological examinations were performed to determine spinal deformities. The type and severity of the spinal deformities were evaluated and their relationships with chest wall deformity subtypes were statistically analyzed. RESULTS: Spinal deformities were identified in 93 (16.97%) patients. The patients were subdivided into 71 (76.3%) male and 22 (23.7%) female patients. A spinal deformity was detected in 57 (13%) of 418 pectus excavatum (PE) patients, in 23 (19%) of 117 pectus carinatum (PC) patients, and in all patients with mixed pectus deformity (PE + PC), syndromic deformity and rib anomalies. In the PE group, scoliosis, and kyphosis were observed at 57.9 and 31.6%, respectively. In the PC group, these rates were 43.5 and 47.8%, respectively. Idiopathic scoliosis was observed in 42 (77.7%) and constituted the most common scoliosis subgroup. The main thoracic curvature was the most common curve pattern, which was observed in 15 (35.7%) patients with idiopathic scoliosis. CONCLUSIONS: Idiopathic scoliosis with main thoracic curvature is the most common deformity in patients with anterior chest wall deformity. Spinal deformities are more common in male patients with chest deformities. Kyphosis is found in a significant number of PE and PC patients. Patients with mixed PE and PC, rib anomalies, and syndromic disease are more likely to have spinal deformities.

Evolution, Current Trends, and Latest Advances of Endoscopic Spine Surgery.

Background: The aging of the population in developing and developed countries has led to a significant increase in the health burden of spinal diseases. These elderly patients often have a number of medical comorbidities due to aging. The need for minimally invasive techniques to address spinal disorders in this elderly population group cannot be stressed enough. Minimally invasive spine surgery (MISS) has several proven benefits, such as minimal muscle trauma, minimal bony resection, lesser postoperative pain, decreased infection rate, and shorter hospital stay. Methods: A comprehensive search of the literature was performed using PubMed. Results: Over the past 40 years, constant efforts have been made to develop newer techniques of spine surgery. Endoscopic spine surgery is one such subset of MISS, which has all the benefits of modern MISS. Endoscopic spine surgery was initially limited only to the treatment of lumbar disc herniation. With improvements in optics, endoscopes, endoscopic drills and shavers, and irrigation pumps, there has been a paradigm shift. Endoscopic spine surgery can now be performed with high magnification, thus allowing its application not only to lumbar spinal stenosis but also to spinal fusion surgeries and cervical and thoracic pathology as well. There has been increasing evidence in support of these newer techniques of spine surgery. Conclusions: For this report, we studied the currently available literature and outlined the historical evolution of endoscopic spine surgery, the various endoscopic systems and techniques available, and the current applications of endoscopic techniques as an alternative to traditional spinal surgery.

Naive Bayes-guided bat algorithm for feature selection.

When the amount of data and information is said to double in every 20 months or so, feature selection has become highly important and beneficial. Further improvements in feature selection will positively affect a wide array of applications in fields such as pattern recognition, machine learning, or signal processing. Bio-inspired method called Bat Algorithm hybridized with a Naive Bayes classifier has been presented in this work. The performance of the proposed feature selection algorithm was investigated using twelve benchmark datasets from different domains and was compared to three other well-known feature selection algorithms. Discussion focused on four perspectives: number of features, classification accuracy, stability, and feature generalization. The results showed that BANB significantly outperformed other algorithms in selecting lower number of features, hence removing irrelevant, redundant, or noisy features while maintaining the classification accuracy. BANB is also proven to be more stable than other methods and is capable of producing more general feature subsets.

Tracking hepcidin level in induced type 2 diabetic rats and how Empagliflozin affects its level.

BACKGROUND: Hepcidin is a hormone that contributes to iron homeostasis, produced either through hepatic or extrahepatic pathways. Its production may be affected by proinflammatory mediators released by macrophages, which play a role in the development of peripheral insulin resistance. Insulin itself may increase the production of hepcidin hormone from pancreatic ß-cells. OBJECTIVES: To evaluate the impact of induction of type 2 diabetes mellitus (T2DM) in albino wister rats on the level of hepcidin. Also, to examine the role of 2-week use of Empagliflozin, a sodium-glucose cotransporter-2 inhibitor (SGLT2 Inhibitor), on the hepcidin level comparing to control. METHOD: An interventional study includes randomization of 36 rats into three groups (A: negative control, B: positive control, and C: Empagliflozin group). Two rats were excluded from the study for different reasons. T2DM was induced using high-fat diet/high-sugar diet (HFD/HSD) for 8 weeks. Empagliflozin was then given to Group C for 2 weeks at a dose of 35 mg/kg/day. Hepcidin level was determined at the baseline, and at week 8 and week 10 intervals. Hepcidin was determined using enzyme-linked immunosorbent assay (ELISA). RESULTS: Hepcidin level significantly increased following the induction of T2DM in both B and C Groups. Hepcidin level in Group B insignificantly reduced 2 weeks after discontinuation of HFD/HSD and significantly reduced in Group C. Group A experienced no statistical difference in hepcidin level at week 10 when compared to baseline. CONCLUSION: Induction of T2DM is associated with a significant increase in the level of hepcidin. Empagliflozin significantly reduced hepcidin level in newly induced diabetic rats.

Characteristics of Otorhinolaryngological Emergencies in the Elderly.

OBJECTIVE: This study was designed to characterize the distribution of otorhinolaryngological emergencies seen in the geriatric population in one year. In this article we present our results and discuss the differences between our results and those reported in the current literature. METHODS: The study was carried out in a tertiary care university hospital. All patients aged 65 years or over that were referred by the general emergency department (ED) to the otorhinolaryngology emergency room in a one-year period were retrospectively reviewed. Demographic characteristics (age, gender), findings of physical examination, accompanying systemic diseases, diagnosis, and treatment methods were documented. Hospitalization and referral needs were also analyzed. RESULTS: In the one-year period from April 2017 to April 2018, a total of 12,780 patients aged 65 or older presented to the ED and the otorhinolaryngology physician was consulted for 195 (1.5%) of these patients. The age range of the patients was 65-96 years, with a mean age of 75 years. The most common cause for presenting to the ED was maxillofacial trauma (31.7%), followed by epistaxis (18.7%). Dyspnea (9.7%) and peripheral facial paralysis (9.7%) were the third most frequent causes. The outcome analysis revealed that 9.7% of the patients were hospitalized. CONCLUSION: Identifying the characteristics of the geriatric patients presenting to EDs is important for developing proper management algorithms. Maxillofacial traumas were the most frequently seen ORL emergencies in our cohort of geriatric patients, followed by epistaxis. The distribution and the prevalence of the cases could differ according to the institutional protocols.

First Reported Cochlear Implantation in a Child with Total Artificial Heart.

We report a case of 15-year-old boy with postlingual bilateral total hearing loss following ototoxic medication during his pediatric intensive care unit stay. The patient received the SynCardia total artificial heart implant (50 mL; SynCardia Systems, Inc., Tucson, AZ, USA) for end-stage biventricular heart failure as a bridge to heart transplant. During his time on the urgent heart transplant wait list, he underwent successful cochlear implantation following optimized coagulation and hemostasis status and appropriate anesthetic preparation. Our case represents the world's first successful cochlear implant in a pediatric patient who received an artificial heart. Despite complexities in this patient population, elective surgical procedures can be performed safely with acceptable morbidity using a collaborative approach with the heart transplant team, including input from cardiovascular surgery, pediatric cardiology, anes thesiology, consultation-liaison psychiatry, physical therapy and rehabilitation, infectious diseases and clinical microbiology, and intensive care unit staff.

Do Magnetically Controlled Growing Rods Stimulate Longitudinal Vertebral Growth in Early-Onset Scoliosis Patients?

OBJECTIVE: Distraction-based systems are the most common systems used in the treatment of early-onset scoliosis. In addition to its corrective and deformity progression preventive properties, its vertebral growth stimulation effect has been proved. Recently popularized magnetically controlled growing rods (MCGRs) showed superior results in terms of outcomes and decreased complication rate. Its vertebral growth stimulation effect has not been studied. The aim of the study is to evaluate the vertebral growth stimulation effect in patients treated with MCGR. METHODS: Patients with progressive scoliosis treated by dual MCGR, who had no obvious lumbar vertebral deformity and had a regular 3-month interval spinal lengthening for at least 30 months, were subdivided into 2 groups according to the inclusion of L3 vertebra within instrumentation segments. The L3 vertebral vertical and horizontal lengths were measured postoperatively and at the last follow-up, and their differences were analyzed statistically in both groups. RESULTS: Twenty-four patients were included; 18 of them had an L3 vertebra outside instrumentation segments, while the other 6 had spanned by MCGR. Uninstrumented L3 were followed up for an average of 36 months. The height difference between initial postoperative examination and the last follow-up was 3.55 mm ± 0.63 mm, and the width difference was 3.85 mm ± 0.75 mm. Conversely, patients with instrumented L3 were followed up for a mean of 38.9 months. Their initial postoperative examination and last follow-up differences in height and width were 6.91 mm ± 1.11 mm and 3.66 mm ± 0.92 mm, respectively. CONCLUSIONS: Frequent distractions stimulate longitudinal vertebral growth in vertebrae spanned by MCGR.

Mid-length Pedicle Screws in Posterior Instrumentation of Scoliosis.

Study Design: Prospective analysis of collected data. Purpose: We determine the need for the use of mid-length pedicle screws (screws with 2.5-mm long increments) during posterior spinal instrumentation. Overview of Literature: Many biomechanical studies have been performed showing that increasing the pedicle screw insertion depth provides an improved resistance to pullout, cyclic loading, and derotational forces, but no intermediate length screws were used. Methods: We prospectively evaluated 120 patients who received posterior segmental instrumentation for structural scoliosis. Preoperatively, 91.44-cm long cassette anteroposterior (AP), lateral, and AP bending radiographs and multiplanar computed tomography were performed in all patients routinely. We measured chord length to determine the maximum probable screw length of all vertebrae. All pedicle screws were attempted to be placed as long as possible. The main intention was at least to engage the subcortical bone of the anterior vertebral cortex. Especially in the apical region, the screws were attempted to be inserted bicortically. The length, level, region, and side of each screw were recorded. Screws with 5-mm increments were called standard length screws (SLS), and middle-sized screws with 2.5-mm increments were called mid-length screws (MLS). Results: Of 2,846 pedicle screws inserted, 1,575 (55.4%) were SLS and 1,271 (44.6%) were MLS, demonstrating a need for MLS in scoliosis surgery (p <0.05). The need for MLS increased significantly in the thoracic region, apical vertebrae, and convex side (p <0.05). Conclusions: If anterior cortex engagement or longer placement of pedicle screws is intended during scoliosis surgery, for safer placement, screws with 2.5-mm increments should be available in posterior instrumentation systems.

Comparison of the Pullout Strength of Different Pedicle Screw Designs and Augmentation Techniques in an Osteoporotic Bone Model.

STUDY DESIGN: Mechanical study. PURPOSE: To compare the pullout strength of different screw designs and augmentation techniques in an osteoporotic bone model. OVERVIEW OF LITERATURE: Adequate bone screw pullout strength is a common problem among osteoporotic patients. Various screw designs and augmentation techniques have been developed to improve the biomechanical characteristics of the bone-screw interface. METHODS: Polyurethane blocks were used to mimic human osteoporotic cancellous bone, and six different screw designs were tested. Five standard and expandable screws without augmentation, eight expandable screws with polymethylmethacrylate (PMMA) or calcium phosphate augmentation, and distal cannulated screws with PMMA and calcium phosphate augmentation were tested. Mechanical tests were performed on 10 unused new screws of each group. Screws with or without augmentation were inserted in a block that was held in a fixture frame, and a longitudinal extraction force was applied to the screw head at a loading rate of 5 mm/min. Maximum load was recorded in a load displacement curve. RESULTS: The peak pullout force of all tested screws with or without augmentation was significantly greater than that of the standard pedicle screw. The greatest pullout force was observed with 40-mm expandable pedicle screws with four fins and PMMA augmentation. Augmented distal cannulated screws did not have a greater peak pullout force than nonaugmented expandable screws. PMMA augmentation provided a greater peak pullout force than calcium phosphate augmentation. CONCLUSIONS: Expandable pedicle screws had greater peak pullout forces than standard pedicle screws and had the advantage of augmentation with either PMMA or calcium phosphate cement. Although calcium phosphate cement is biodegradable, osteoconductive, and nonexothermic, PMMA provided a significantly greater peak pullout force. PMMA-augmented expandable 40-mm four-fin pedicle screws had the greatest peak pullout force.

Short Segment Spinal Instrumentation in Early-onset Scoliosis Patients Treated With Magnetically Controlled Growing Rods: Surgical Technique and Mid - Short-term Outcomes.

STUDY DESIGN: A prospective, a single-institution, nonrandomized study. OBJECTIVE: The aim of this study was to evaluate the safety and effectivity of short-segment instrumentation in early-onset scoliosis (EOS) patients treated by magnetic-controlled growing rods (MCGRs). SUMMARY OF BACKGROUND DATA: Despite the common use of conventional growing rods and the recent popularity of MCGR in the treatment of progressive EOS, distal instrumented vertebra and number of the spanned levels are not standardized. METHODS: Patients with progressive EOS, characterized by the major thoracic curve and nonstructural compensatory curve, were a candidate to be treated by dual MCGR short segment spinal instrumentation spanning the major thoracic curve; such patients are followed up for a minimum period of 30 months. Radiological data were collected and analyzed in terms of Cobb angle of both primary and secondary curve, kyphosis angle, T1-T12, and T1-S1 distances, and T1-T12/T1-S1 ratio in preoperative, postoperative, and last follow-up. RESULTS: Sixteen patients with different diagnoses of EOS, mean age at the operation was 7 years and 10 months (5 years and 6 months-9 years and 10 months), and mean period of follow-up was 37 (30-54) months. The Cobb angle of both major and compensatory curve are corrected by the mean value of 62° (44-85), 35° (22-45) preoperatively to 29° (12-49), 14° (9-24) postoperatively, and maintained at 28° (10-47), 10° (2-20) in the last follow-up, respectively. The T1-T12/T1-S1 ratio was 0.58 preoperatively, 0.6 postoperatively, and 0.62 at the last follow-up. The average yearly T1-T12 and T1-S1 length increase were calculated as 7 and 9 mm/year, respectively. CONCLUSION: Selective fusion principals are applicable to EOS, in that short segment instrumentation with MGCR in thoracic curve EOS patients is an effective technique in correction of both structural and compensatory curve, and in maintaining the correction during subsequent nonsurgical spinal distraction. LEVEL OF EVIDENCE: 4.

Lack of direct effect of adiponectin on vascular smooth muscle cell BKCa channels or Ca2+ signaling in the regulation of small artery pressure-induced constriction.

The aim of this study was to investigate mechanisms by which adiponectin influences vascular Ca2+ signaling, K+ channel activity and thus contractile tone of small arteries. Vasodilation to adiponectin was studied in mesenteric resistance arteries constricted with intraluminal pressure. Ca2+ signals were characterized using high speed confocal microscopy of intact arteries. Patch clamp investigated the effect of adiponectin on individual VSMC potassium (K+) channel currents. Adiponectin dilated arteries constricted with pressure-induced tone by approximately 5% and the induced vasodilation was only transient. The dilation to adiponectin was reduced by pharmacological interruption of the Ca2+ spark/large conductance activated K+ (BK) channel pathway but from a physiological perspective, interpretation of the data was limited by the small effect. Neither Adiponectin nor the presence of intact perivascular adipose tissue (PVAT) influenced Ca2+ spark or Ca2+ wave frequency or characteristics. Studied using a perforated patch approach, Adiponectin marginally increased current through the VSMC BK channel but this effect was lost using the whole cell technique with dialysis of the cytoplasm. Adiponectin did not change the frequency or amplitude of Ca2+ spark-induced transient outward currents (STOC). Overall, our study shows that Adiponectin induces only a small and transient dilation of pressure constricted mesenteric arteries. This vasodilatory effect is likely to be independent of Ca2+ sparks or direct BK channel activation.

Magnetic Controlled Growing Rods as a Treatment of Early Onset Scoliosis: Early Results With Two Patients.

STUDY DESIGN: Prospective unicentral nonrandomized study. OBJECTIVE: To evaluate the safety and effectivity profile of magnetic controlled growing rods (MCGR) in patients with early onset scoliosis (EOS). SUMMARY OF BACKGROUND DATA: Conventional growing rods are the most commonly used growth sparring devices in the treatment of EOS, as this technique requires repeated surgical operations for lengthening; it is associated with high rate of complications and increased costs. MCGR in treatment of EOS is effective in correcting deformity whereas allowing continuous spinal growth as reported by a few studies. METHODS: A total of 18 patients with progressive EOS were treated by MCGR, two of them had undergone final fusion operation. Patients were followed-up for a minimium time of 9 months from the time of initial surgery. Radiological data were analyzed in terms of Cobb angle, kyphosis angle, T1-T12, and T1-S1 distances in preoperative, postoperative, and last follow up. RESULTS: The mean preoperative Cobb and kyphosis angle were 68° (44-116°) and 43° (98-24°), it was corrected to 35° (67-12°) and 29° (47-21°) immediately after initial operation and maintained at 34.5° (52-10°) and 33° (52-20°) at last follow up, respectively.The mean preoperative T1-T12 and T1-S1 distance were 171 mm (202-130 mm) and 289 mm (229-370 mm), it was increased to 197 mm (158-245 mm) and 330 mm (258-406mm) immediately after initial operation and further increased to 215 mm (170-260 mm) and 357 mm (277-430 mm) at last follow up, respectively.Two patients had undergone final fusion, they had overall mean Cobb angle correction of 66° (62-70°), and kyphosis angle change of 53° (26-80°). Total height gain in T1-T12 and T1-S1 of 80.5 mm (67-94 mm) and 119 mm (105-133 ), respectively. CONCLUSION: MCGR is safe and effective technique in correction of EOS deformity and in maintaining the correction during nonsurgical distraction procedures. A further correction of the deformity and more spinal height gain can be achieved in the final fusion operation. LEVEL OF EVIDENCE: 3.

Pressure-induced oxidative activation of PKG enables vasoregulation by Ca2+ sparks and BK channels.

Activation of Ca2+-sensitive, large-conductance potassium (BK) channels in vascular smooth muscle cells (VSMCs) by local, ryanodine receptor-mediated Ca2+ signals (Ca2+ sparks) acts as a brake on pressure-induced (myogenic) vasoconstriction-a fundamental mechanism that regulates blood flow in small resistance arteries. We report that physiological intraluminal pressure within resistance arteries activated cGMP-dependent protein kinase (PKG) in VSMCs through oxidant-induced formation of an intermolecular disulfide bond between cysteine residues. Oxidant-activated PKG was required to trigger Ca2+ sparks, BK channel activity, and vasodilation in response to pressure. VSMCs from arteries from mice expressing a form of PKG that could not be activated by oxidants showed reduced Ca2+ spark frequency, and arterial preparations from these mice had decreased pressure-induced activation of BK channels. Thus, the absence of oxidative activation of PKG disabled the BK channel-mediated negative feedback regulation of vasoconstriction. Our results support the concept of a negative feedback control mechanism that regulates arterial diameter through mechanosensitive production of oxidants to activate PKG and enhance Ca2+ sparks.

Neglected lunate dislocation presenting as carpal tunnel syndrome.

Most of carpal tunnel syndrome cases are idiopathic, and secondary causes are so rare that can be easily missed. We present a patient with neglected undiagnosed lunate dislocation compressing on median nerve causing its signs and symptoms.