Carotid endarterectomy for symptomic and asymptomic stenosis: Report of 65388 cases (Russian register).

AIM: Analysis of in-hospital and long-term results of carotid endarterectomy in patients with asymptomatic and symptomatic stenoses. MATERIALS AND METHODS: The sample was formed by completely including all cases of carotid endarterectomy (n = 65,388) performed during the period from May 1, 2015 to November 1, 2023. Depending on the symptomatic/asymptomatic nature of the stenosis, all patients were divided into two groups: group 1 - n = 39,172 (75.2%) - patients with asymptomatic stenosis; Group 2 - n = 26216 (24.8%) - patients with symptomatic stenosis. The postoperative follow-up period was 53.5 ± 31.4 months. RESULTS: In the hospital postoperative period, the groups were comparable in the incidence of death (group 1: n = 164 (0.41%); group 2: n = 124 (0.47%); p = .3), transient ischemic attack (group 1: n = 116 (0.29%); group 2: n = 88 (0.33%); p = .37), myocardial infarction (group 1: n = 32 (0.08%); group 2: n = 19 (0.07%); p = .68), thrombosis of the internal carotid artery (group 1: n = 8 (0.02%); group 2: n = 2 (0.007%); p = 0, 19), bleeding (group 1: n = 58 (0.14%); group 2: n = 33 (0.12%); p = .45). In group 2, ischemic stroke developed statistically more often (group 1: n = 328 (0.83%); group 2: n = 286 (1.09%); p = .001), which led to a higher value of the combined endpoint (group 1: n = 640 (1.63%); group 2: n = 517 (1.97%); p = .001). In the long-term postoperative period, the groups were comparable in cases of death (group 1: n = 65 (0.16%); group 2: n = 41 (0.15%); p = .76) and death from cardiovascular causes (group 1: n = 59 (0.15%); group 2: n = 33 (0.12%); p = .4). A greater number of ischemic strokes were detected in patients of group 2 (group 1: n = 213 (0.54%); group 2: n = 187 (0.71%); p = .006). In group 1, hemodynamically significant restenosis (≥70%) of the internal carotid artery was more often diagnosed (group 1: n = 974 (2.49%); group 2: n = 351 (1.34%); p < .0001) and myocardial infarction (group 1: n = 66 (0.16%); group 2: n = 34 (0.13%); p < .0001). When analyzing stroke-free survival, analysis of Kaplan-Meier curves showed that a statistically larger number of strokes were diagnosed in group 2 (p < .0001). CONCLUSION: Due to the fact that the patients were initially not comparable for a number of indicators, to achieve balance, we applied propensity score matching analysis. Thus, group 1 consisted of 24,381 patients, and group 2 consisted of 17,219 patients. In the hospital postoperative period, statistically significant differences were obtained only in the combined end point, which was greater in group 2 (group 1: n = 465 (1.9%); group 2: n = 382 (2.2%); p = .02). In the long-term follow-up period, after applying propensity score matching, no statistically significant differences were obtained between groups.

The results of thrombectomy from the arteries of the lower extremities in patients infected with SARS-CoV-2 Omicron variant with different severity of respiratory failure.

GOAL: Analysis of the results of thrombectomy from the arteries of the lower extremities in patients with COVID-19 against the background of different severity of respiratory failure. MATERIALS AND METHODS: This retrospective, cohort, comparative study for the period from 05/01/2022 to 20/07/2022 included 305 patients with acute thrombosis of the arteries of the lower extremities against the background of the course of COVID-19 (SARS-CoV-2 Omicron variant). Depending on the type of oxygen support, 3 groups of patients were formed: group 1 (n = 168) - oxygen insufflation through nasal cannulas; group 2 (n = 92) - non-invasive lung ventilation; and group 3 (n = 45) - artificial lung ventilation. RESULTS: Myocardial infarction and ischemic stroke were not detected in the total sample. The highest number of deaths (group 1: 5.3%, n = 9; group 2: 72.8%, n = 67; group 3: 100%, n = 45; p < 0.0001), rethrombosis (group 1 : 18.4%, n = 31; group 2: 69.5%, n = 64; group 3: 91.1%, n = 41; p < 0.0001), and limb amputations (group 1: 9.5%, n = 16; group 2: 56.5%, n = 52; group 3: 91.1%, n = 41; p < 0.0001) was recorded in group 3 (ventilated) patients. CONCLUSION: In patients infected with COVID-19 and on artificial lung ventilation, a more aggressive course of the disease is noted, expressed in an increase in laboratory parameters (C-reactive protein, ferritin, interleukin-6, and D-dimer) of the degree of pneumonia (CT-4 in overwhelming number) and localization of thrombosis of the arteries of the lower extremities, mainly in the tibial arteries.

ArtiLock: Smartphone User Identification Based on Physiological and Behavioral Features of Monosyllable Articulation.

Although voice authentication is generally secure, voiceprint-based authentication methods have the drawback of being affected by environmental noise, long passphrases, and large registered samples. Therefore, we present a breakthrough idea for smartphone user authentication by analyzing articulation and integrating the physiology and behavior of the vocal tract, tongue position, and lip movement to expose the uniqueness of individuals while making utterances. The key idea is to leverage the smartphone speaker and microphone to simultaneously transmit and receive speech and ultrasonic signals, construct identity-related features, and determine whether a single utterance is a legitimate user or an attacker. Physiological authentication methods prevent other users from copying or reproducing passwords. Compared to other types of behavioral authentication, the system is more accurately able to recognize the user's identity and adapt accordingly to environmental variations. The proposed system requires a smaller number of samples because single utterances are utilized, resulting in a user-friendly system that resists mimicry attacks with an average accuracy of 99% and an equal error rate of 0.5% under the three different surroundings.

Effects of different types of carotid endarterectomy on the course of resistant arterial hypertension.

OBJECTIVE: Analysis of the dynamics of systolic blood pressure (SBP) and the results of various types of carotid endarterectomy (СЕЕ) (classical with plasty of the reconstruction zone with a patch, eversion, formation of a new bifurcation, autoarterial reconstruction, glomus-saving techniques) in patients with resistant arterial hypertension (RAH). MATERIALS AND METHODS: The actual cohort, comparative, retrospective, open research for the period from January 2013 to December 2021 includes 1577 patients with significant hemodynamic stenosis of the internal carotid artery Depending on revascularization strategy five groups were formed: Group 1: 18.3% (n = 289) - classical Carotid endarterectomy with plasty of the reconstruction zone with a patch (from diepoxy-treated xenopericardium or synthetic); Group 2: 29.9% (n = 472) - eversional CEE with cut-off of carotid gloomus (CG); Group 3: 6.9% (n = 109) - the formation of a new bifurcation; Group 4: 7.4% (n = 117) - autoarterial reconstruction; Group 5: 37.4% (n = 590) - glomus-saving CEE (1 technique - according to A.N. Kazantsev; two technicians - according to R.A. Vinogradov; three technicians - according to K.A.Antsupov). According to the 24-h blood pressure monitor in the preoperative period, the following degrees of AH were identified: 1° - 5.7% (n = 89); 2° - 64.2% (n = 1013); and 3° - 30.1% (n = 475). RESULTS: In the postoperative period, no significant differences were obtained in the frequency of deaths, myocardial infarction, stroke, hemorrhagic transformation. However, according to the frequency of the combined endpoint (death + myocardial infarction + ischemic stroke + hemorrhagic transformation), the lowest rates were observed in the group of classical carotid endarterectomy with plasty of the reconstruction zone with a patch and glomus-sparing CEE (group 1: 1.03% (n = 3); group 2: 3.6% (n = 17); group 3: 3.67% (n = 4); group 4: 2.56% (n = 3); group 5: 0.5% (n = 3); p = 0.10). This is due to the absence of cases of labile AH and hypertensive crises among patients of groups 1 and 5, which was ensured by the preservation of carotid glomus (CG). As a result, the number of patients with 2 and 3 degrees of hypertension in these groups decreased statistically significantly. The vast majority of patients after these operations achieved a stable target SBP. In groups 2, 3, and 4, there was a statistically significant increase in the number of patients with 2 and 3 degrees of AH, which is associated with excision of the CG. CONCLUSION: Classical CEE and glomus-sparing CEE techniques make it possible to achieve a stable target SBP level in patients with RAH as a result of CG preservation. Removal or traumatization of the latter during eversional CEE, the formation of a new bifurcation, autoarterial reconstruction is accompanied by the development of labile hypertension, an increase in the degree of hypertension and a high risk of hemorrhagic transformation in the brain. Thus, the most effective and safe types of CEE in the presence of RAH are classical CEE with plasty of the reconstruction zone with a patch and glomus-sparing CEE, accompanied by the lowest incidence of adverse cardiovascular events caused by postoperative hypertensive crisis and hyperperfusion syndrome.

Features of Carotid Endarterectomy in Russia. How do we Resolution Issues?

This review of the literature discusses the solution of unresolved issues related to carotid endarterectomy in Russia: (1) A program has been created for choosing the tactics of revascularization of patients with simultaneous atherosclerotic lesions of the coronary and carotid arteries; (2) Using the methods of computer modeling, studying the genetics and morphology of restenosis, it was found that the classic carotid endarterectomy with plasty of the reconstruction zone with a patch is an unsafe type of revascularization; (3) An eversion carotid endarterectomy with transposition of the internal carotid artery over the hypoglossal nerve has been developed, which makes it possible to prevent damage to the latter during repeated carotid endarterectomy for restenosis; (4) It has been established that carotid endarterectomy is associated with a high risk of complications in patients over 75 years of age; (5) It has been proven that emergency carotid endarterectomy in the first hours after the development of a stroke is not safe because. combined with the maximum number of all non-favorable cardiovascular events; (6) 3 new types of carotid endarterectomy with carotid glomus preservation have been developed.

Factors associated with all-cause mortality in patients with coronary artery chronic total occlusions undergoing revascularization (percutaneous coronary intervention or surgery) or medical treatment.

Aim    Chronic total occlusion of a coronary artery (CTO) is a predictor of early and late cardiovascular mortality and poor cardiovascular outcomes in patients with coronary artery disease. The purpose of this study was to identify predictors of all-cause mortality in CTO patients that underwent invasive treatment.Material and methods    Patients between 2012 and 2018 with CTO in at least one vessel, as demonstrated by coronary angiography, were included retrospectively in the study. The patients were divided into two groups, an intervention group (percutaneous and surgical revascularization) and a medical group.Results    A total of 543 patients were studied, 152 females (28%) and 391 males (72%). The median follow-up period was 49 (26-72) mos. A total of 186 (34.2%) patients in the medical group and 357 (65.8%) patients in the invasive therapy group were followed. The 5-yr death rate was observed in 50 (26.9%) patients in the medical group and 53 (14.8%) patients in the intervention group, and it was found to be statistically higher in the medical group (p=0.001). In multivariable analysis, heart failure (odds ratio (OR): 1.92, 95% CI: 1.18-3.14; p=0.01), higher glucose levels (OR: 1.05, 95% CI: 1,02-1.08; p=0.04), lower albumin levels (OR: 0.49, 95% Cl: 0.32-0.72; p=0.001), SYNTAX score (OR: 1.03, 95% CI: 1.01-1.05; p=0.001), and CTO (≥2 occluded artery) (OR: 0.42, 95% CI: 0.22-0.72; p=0.01) were independent factors for all-cause mortality.Conclusion    In comparison to the revascularized group, there was an increase in mortality among CTO patients treated medically. Heart failure, SYNTAX score, albumin, glucose, and CTO (≥2 occluded arteries) were independent risk factors for all-cause mortality.

Single Nucleotide Polymorphisms in IL-1A RS1800587, IL-1B RS1143634 and Vitamin D Receptor Rs731236 in Stage III Grade B/C Periodontitis.

The purpose of the study is to determine the prevalence of interleukin (IL)-1A (rs1800587), IL-1B (rs1143634) and vitamin D receptor (VDR) (TaqI, rs731236) gene polymorphisms in the Turkish population and their association with Stage III Grade B/C periodontitis. Systemically and periodontally healthy individuals (N = 100) and Stage III Grade B/C periodontitis patients (N=100) based on clinical and radiographic examination were included in this research. Clinical attachment level, probing depth, bleeding on probing, plaque and gingival indices of the subjects were measured. Genotyping of IL-1A (rs1800587), IL-1B (rs1143634) and VDR (rs731236) polymorphisms was conducted by Real Time PCR. Allelic and genotypic distributions of IL-1A (rs1800587) gene polymorphism were not associated with periodontitis (p>0.05). In IL-1B (rs1143634) gene polymorphism, the C allele was detected more frequently in healthy individuals compared with the periodontitis patients (p=0.045). CC genotype and C allele in VDR (rs731236) gene polymorphism was higher in periodontitis patients (p=0.031, p=0.034, respectively). In comparison with Grade B periodontitis patients and healthy subjects, CC genotype and C allele were observed more frequently in the Grade B periodontitis in terms of alleles (C/T) and genotypes for VDR (rs731236) polymorphism (p=0.024, p=0.008, respectively). This study presents that the VDR (rs731236) polymorphism are associated with enhanced susceptibility to Stage III periodontitis in the Turkish population. Furthermore, VDR (rs731236) polymorphism may be used as an identification criteria to discriminate Grade B and Grade C in Stage III periodontitis.

Self-fulfillment degree of construction and demolition waste management capability based on the Triple-balance theory: A case study of Guangdong-Hong Kong-Macao Greater Bay Area.

Construction and demolition waste (C&DW) has become part of the largest waste stream globally and many cities are facing the shortage of management capability to treat C&DW. These cities seek to transport their C&DW to their neighbor cities for recycling or landfilling, which is recognized as the cross-regional management of C&DW. However, there were few studies to investigate the mechanism of cross-regional mobility in C&DW field. This study developed a model to evaluate the self-fulfillment degree of C&DW management capability at regional level based on the Triple-balance theory. Guangdong-Hong Kong-Macao Greater Bay Area (GBA) was selected as the study case, and the data was collected through on-site surveys, expert interviews, and desktop surveys. The results showed that the self-fulfillment degree of C&DW management capability of the cities, such as Guangzhou, Zhuhai, Foshan, Dongguan, Jiangmen, and Zhaoqing was high, which meant these cities could well manage the C&DW generated within the regions under current situation. The self-fulfillment degree of management capability of Macao, Huizhou, and Zhongshan was evaluated as medium; while the indicators of Hong Kong and Shenzhen fell into low category, which meant they needed to transport surplus C&DW to other cities for further treatment. The research is significant as it provides an innovative evaluation model considering the cross-regional mobility for C&DW management performance assessment. Besides, the findings could assist the waste management sectors to plan the C&DW treatment facilities in GBA, while other cities could also benefit from this study regarding to the cross-regional mobility management of C&DW.

Determinants Affecting Purchase Willingness of Contractors towards Construction and Demolition Waste Recycling Products: An Empirical Study in Shenzhen, China.

Waste recycling is a critical method to effectively address environmental issues raised by construction and demolition waste (C&DW). As highlighted in previous studies, the contractor is considered the primary purchaser for recycled C&DW products. However, there is a limited understanding of the factors affecting the contractor's purchase willingness towards C&DW recycling products. This study investigated these key drivers using the Exploratory Sequential Mixed Approach. Firstly, a hypothetical model was developed based on the theory of planned behavior (TPB). Secondly, a questionnaire survey was then employed in data collection. Thirdly, structural equation modeling (SEM) was adopted for data analysis. It is revealed that multiple factors directly affect the contractor's purchase willingness towards C&DW recycling products. These factors include government measures, the contractor's attitude, perceived behavioral control, perceived consumer effectiveness, and subjective norms. Besides, recycling product information indirectly affects the contractor's purchase willingness. Based on the findings, the study provides strategies for the government, contractors, recycling enterprises, and public buyers to increase C&DW recycling products' purchase willingness. Findings derived from the empirical study can be used as a theoretical reference for government departments to develop related promotion policies. Moreover, the suggestions provided are helpful to guide recycling enterprises to promote their products.

Micro-CT evaluation of the quality of root fillings when using three root filling systems.

AIM: To evaluate the percentage volumes of filling materials and voids in single-rooted teeth filled with three different filling systems using micro-computed tomography (micro-CT). METHODOLOGY: Thirty single-rooted human teeth were used. After preparation of the root canals, the teeth were randomly divided into three groups (n = 10). The canals were filled with EndoREZ, ActiV GP or AH Plus/gutta-percha. Each specimen was scanned using a micro-CT device at a resolution of 13.68 µm. Percentage volumes of root filling materials and voids were calculated and data were analysed statistically using the Kruskal-Wallis test and the Mann-Whitney U-test with Bonferroni adjustment. Within each group, the Friedman test was performed with the Wilcoxon signed-rank test to detect discrepancies. RESULTS: The percentage volume of filling material was significantly lower in the ActiV GP group than in the other groups (P < 0.05), whilst the percentage volume of voids was significantly higher in the ActiV GP group than in the other groups (P < 0.05). CONCLUSION: None of the systems were associated with void-free root fillings. The ActiV GP system had a significantly higher percentage volume of voids than the other systems.

Comparison of propofol-remifentanil and propofol-ketamine combination for dilatation and currettage: a randomized double blind prospective trial.

OBJECTIVE: The purpose of this study was to compare the propofol-remifentanil combination and propofol-ketamine combination for Dilatation and Curettage (DC) procedure. PATIENTS AND METHODS: This prospective, double blind, and randomized study comprised 81 female patients undergoing diagnostic DC. Patients were randomly allocated to one of two groups; propofol-remifentanil (Group PR, n= 44) or propofol-ketamine (Group PK, n= 37). The level of sedation was assessed with the Ramsay Sedation Score (RSS). The patients' RSS scores were maintained at 4-5 with an additional 0.5 mg/kg bolus dose of propofol. Heart rate (HR), mean blood pressure (MBP), peripheral oxygen saturation (SpO2), and RSS were recorded. The Modify Aldrete Score (MAS) was used for postoperative recovery evaluation, and the time to reach MAS score of 10 was recorded. Total dose of propofol, procedure time, side effects, and satisfaction scores of patient and surgeon were also recorded. RESULTS: The mean HR and MBP values of Group PR were lower than those of Group PK, at all recording times. Sedation levels were significantly higher in Group PK. The total dose of propofol consumed was significantly higher in Group PR. The recovery time of Group PK was significantly longer than that of Group PF (p<0.05). Nausea-vomiting and bradycardia were more frequent in the Group PR. There was no difference in patient and surgeon satisfaction between the two groups. CONCLUSIONS: Ketamine-propofol combination provides better hemodynamic stability and better quality of sedation than propofol-remifentanil combination. Ketamine still seems as an advantageous and safe drug for such procedure.

Assessment of left atrial functions in cardiac syndrome X.

OBJECTIVE: Cardiac syndrome X (CSX) affects left ventricular functions due to myocardial ischaemia. In this study our aim was to determine the changes in left atrial functions in patients with CSX. PATIENTS AND METHODS: One-hundred patients (M/F; 57/43) diagnosed with CSX in whom ischaemia was detected at exercise test and myocardial perfusion scintigrapghy with normal coronary angiogram and control group of 80 subjects (M/F; 40/40) were recruited into the study. In transthoracic echocardiography and tissue doppler echocardiography, left ventricular and atrial functions were recorded. RESULTS: As compared to control group,left ventricular diastolic functions were impaired (E/A; 0.95 ± 0.18 vs 1.11 ± 0.29 p < 0.001), left ventricular end-diastolic pressures were increased (E/Em; 8.1 ± 1.85 vs 6.9 ± 1.74 p < 0.05), and left atrial maximum volume, left atrial pre-A volume,left atrial minimum volume were increased in patients with CSX. Left atrial conduit volume was significantly decreased in patients with cardiac syndrome. Left atrial passive emptying volume (LAPEV), left atrial active emptying volume (LAAEV) and left atrial total emptying volume (LATEV) were significantly increased in patients with cardiac syndrome X. Left atrial passive ejection fration (LAPEF) was found similar between the study groups.Left atrial active ejection fraction (LAAEF) was found significantly increased (37.85 ± 11.89 vs 33.60 ± 9.21; p = 0.009) in patients with CSX. Left atrial total ejection fraction (LATEF) was increased in the group with cardiac syndrome X but it didn't reach statistical significance (60.85 ± 8.73 vs 58.36 ± 8.29; p = 0.054). CONCLUSIONS: Left atrial active contractile pump function increase in response to impaired left ventricular diastolic functions in CSX. Increased left atrial pump function represents a compensatory mechanism in patients with CSX. These results point out the importance of maintaining sinus rythm in patients with CSX.

Internal Quality Control Practices in Coagulation Laboratories: recommendations based on a patterns-of-practice survey.

INTRODUCTION: Internal quality control (IQC) procedures are crucial for ensuring accurate patient test results. The IQMH Centre for Proficiency Testing conducted a web-based survey to gather information on the current IQC practices in coagulation testing. METHODS: A questionnaire was distributed to 174 Ontario laboratories licensed to perform prothrombin time (PT) and activated partial thromboplastin time (APTT). RESULTS: All laboratories reported using two levels of commercial QC (CQC); 12% incorporate pooled patient plasma into their IQC program; >68% run CQC at the beginning of each shift; 56% following maintenance, with reagent changes, during a shift, or with every repeat sample; 6% only run CQC at the beginning of the day and 25% when the instruments have been idle for a defined period of time. IQC run frequency was determined by manufacturer recommendations (71%) but also influenced by the stability of test (27%), clinical impact of an incorrect test result (25%), and sample's batch number (10%). IQC was monitored using preset limits based on standard deviation (66%), precision goals (46%), or allowable performance limits (36%). 95% use multirules. Failure actions include repeating the IQC (90%) and reporting patient results; if repeat passes, 42% perform repeat analysis of all patient samples from last acceptable IQC. CONCLUSION: Variability exists in coagulation IQC practices among Ontario clinical laboratories. The recommendations presented here would be useful in encouraging standardized IQC practices.

Critical values in hematology.

INTRODUCTION: Critical values are life-threatening results that require immediate notification to the patient's healthcare provider. Accreditation bodies require laboratories to establish critical values. A survey of Ontario laboratories was conducted to determine current practice for critical values in hematology. METHODS: The survey was sent to 182 participants questioning sources for establishing critical values, levels, review frequency, delta checks, and reporting. The survey was completed by laboratory managers, supervisors, technical specialists, senior technologists, and bench technologists working in hematology. RESULTS: The majority of participating laboratories have established critical values limits for hemoglobin, leukocyte counts, and platelet counts. Most laboratories also include the presence of malaria parasites and blast cells. Some laboratories reported the presence of plasma cells, sickle cells, schistocytes, and spherocytes as critical values. Multiple sources are used for establishing a critical value policy. There was variability for the frequency of critical values review. Rules may differ for a first-time patient sample vs. a repeat patient sample. Delta checks are seldom used to determine whether a result should be called a critical value. Most participants require the individual taking the critical result(s) to read back and confirm that they are directly involved with the patient's care. CONCLUSION: There is a lack of consensus for critical values reporting in hematology. As critical value reporting is crucial for patient safety, standardization of this practice would be beneficial.

Are there differences on tooth movement between different sectional canine retractors?

The aim of this study was to compare the effects of two retraction springs, demonstrating differences in reactivation and constancy of force, on tooth movement during canine distalization. Upper and lower canines of 16 patients (9 females, 7 males; mean age 14.6±1.7 years) with Angle Class I or II malocclusion were included in the study. Left upper and lower canines were distalized using Poul Gjessing (PG) retractors, whereas right canines of the same patients were distalized using Hybrid retractors. Angular and linear measurements were performed on lateral cephalometric radiographs and dental models taken prior to and at the end of canine distalization. Paired Samples t-test, Repeated Measures of Analysis of Variance and Greenhouse-Geisser tests were used for statistical analysis. The mean rates of canine distalization in PG retractors were 1.03 and 0.88 mm/months and 1.13 and 0.93 mm/months for Hybrid retractors for upper and lower canines, respectively. No significant differences were detected in the rate of canine distalization, sagittal and vertical movement of canines, and first molars between retractors or arches. Despite the differences in reactivation and constancy of the forces between PG and Hybrid retractors, both revealed similar canine distalization, distal tipping, rotation, and anchorage loss of molars. As a clinical point of view, Hybrid retractors could provide more benefits due to fewer activation requirements.

Structural brain abnormalities in patients with Parkinson disease: a comparative voxel-based analysis using T1-weighted MR imaging and magnetization transfer imaging.

BACKGROUND AND PURPOSE: In PD, tissue damage occurs in specific cortical and subcortical regions. Conventional MR images have only limited capacity to depict these structural changes. The purpose of the current study was to investigate whether voxel-based MT imaging could indicate structural abnormalities beyond atrophy measurable with T1-weighted MR imaging. MATERIALS AND METHODS: Thirty-six patients with PD without dementia (9 in H&Y stage 1, thirteen in H&Y 2, eleven in H&Y 3, three in H&Y 4) and 23 age-matched control subjects were studied with T1-weighted MR imaging and MT imaging. Voxel-based analyses of T1-weighted MR imaging was performed to investigate brain atrophy, while MT imaging was used to study abnormalities within existing tissue. Modulated GM and WM probability maps, sensitive to volume, and nonmodulated maps, indicative of tissue density, were obtained from T1-weighted MR imaging. Effects seen on MTR images, but absent on density maps, were attributed to damage of existing tissue. RESULTS: Contrary to T1-weighted MR imaging, MT imaging was sensitive to the progression of brain pathology of the neocortex and paraventricular WM. MTR images and T1-based volume images, but not density images, showed a progression of disease in the olfactory cortex, indicating the occurrence of atrophy as well as damage to existing tissue in this region. MTR images revealed bilateral damage to the SN, while T1-weighted MR imaging only showed left-sided abnormalities. CONCLUSIONS: The findings suggest that voxel-based MT imaging permits a whole-brain unbiased investigation of CNS structural integrity in PD and may be a valuable tool for identifying structural damage occurring without or before measurable atrophy.

Diagnostic approach to reveal retroperitoneal injury during lumbar discectomy.

For decades, lumbar discectomy has been one of the most common surgical practices performed by neurosurgeons. Although it has proved to be an effective and safe surgical procedure, life threatening complications may occur in rare cases, including iliac artery and/or vein injuries, superior rectal artery injury, common iliac artery aneurysms, iliac arteriovenous fistula, intestinal injuries, and ureteral injuries. Ureteral damage during the lumbar L4-5 microdiscectomy was reported in a slim 50 year-old male patient. Because of a small amount of bleeding occurred during the surgery as soon as the patient came out of anesthesia, an angio-computed tomography (CT) of the abdomen was performed. It showed no hematoma and no major vascular injury, but air bubbles were seen in the retroperitoneal region, indicating that perforation had occurred. The patient was then monitored carefully for immediate and possible subsequent injuries, in this way; ureteral damage was found and repaired. This is perhaps the first such case report in the literature of the early detection of ureteral damage using an angio CT scan. If there is a suspicion of perforation of the anterior annulus fibrosus and anterior longitudinal ligaments but no indication for an emergency laparotomy, an abdominal angio CT done immediately after the surgery and an abdominal non-contrast CT 4 hours later will give sufficient information concerning the potential occurrence of nearly all the major complications associated with lumbar discectomy.

Direct observation of polarons in electron populated quantum dots by resonant Raman scattering.

The general problem of the pairing of strongly interacting elementary excitations producing new quasiparticles such as polarons arises in many areas of solid state physics. Recent interest in polaron formation in semiconductor quantum dots has been motivated by the need to understand the physical nature of the carrier relaxation processes and their role in quantum-dot based devices. We report on the direct observation of polarons in InAs/GaAs self-assembled quantum dots populated by few electrons where the polarons are strongly coupled modes of quantum dot phonons and electron intersublevel transitions. The degree of coupling is varied in a systematic way in a set of samples having electron intersublevel spacing changing from larger to smaller than the longitudinal optical phonon energy. The signature of polarons is evidenced clearly by the observation of a large (12-20 meV) anticrossing for both InAs and GaAs-like quantum dot phonons using resonant Raman spectroscopy.

Quantum dots for terahertz generation.

Nanostructures made of semiconductors, such as quantum wells and quantum dots (QD), are well known, and some have been incorporated in practical devices. Here we focus on novel structures made of QDs and related devices for terahertz (THz) generation. Their potential advantages, such as low threshold current density, high characteristic temperature, increased differential gain, etc, make QDs promising candidates for light emitting applications in the THz region. Our idea of using resonant tunneling through QDs is presented, and initial results on devices consisting of self-assembled InAs QDs in an undoped GaAs matrix, with a design incorporating a GaInNAs/GaAs short period superlattice, are discussed. Moreover, shallow impurities are also being explored for possible THz emission: the idea is based on the tunneling through bound states of individual donor or acceptor impurities in the quantum well. Initial results on devices having an AlGaAs/GaAs double-barrier resonant tunneling structure are discussed.