4,269 research outputs found
Vertebral level and measurements of conus medullaris and dural sac termination with special reference to the apex of the sacral hiatus: anatomical and magnetic resonance imaging radiologic study
Background: Anatomical orientation of the caudal space and termination level of conus medullaris (CMT) and dural sac (DST) has great significance for anaesthetists and neurosurgeons. This study aimed to explore the anatomical landmarks important to perform save spinal anaesthesia, lumber puncture and caudal analgesia through the correlation between the vertebral level of CMT, DST and sacral hiatus apex (SHA) in human cadavers and by using magnetic resonance imaging (MRI).
Materials and methods: Sixty adult cadavers (40 males, 20 females) and 200 (100 males, 100 females) MR lumbosacral images of 16–69-year-old persons were used in this study. Vertebral level of CMT, DST and SHA and their linear distances were determined in cadavers and MRI. Also, anteroposterior diameter at SHA, length and thickness of sacrococcygeal membrane were measured as well, and correlate these levels and their distances with age and sex.
Results: Mean and highest frequent number of MRI vertebral level of CMT was observed at lower third of L1 in men and L1-2 disc in women, that of DST at upper third of S2 in men and middle third of S2 in women, while SHA was seen at middle third of S4 in both men and women with no significant (p > 0.05) age or gender differences. In 5% of cases, CMT, DST and SHA were seen at vertebral level below L2, below S2-3 and above S3, respectively. However, mean vertebral level of CMT, DST, SHA was observed at L1L, S2M and S4U without sex difference in cadaveric specimens, respectively. All linear distances of men MRI revealed significant difference (p < 0.05) compared with those of women except thickness of sacrococcygeal membrane and anterposterior diameter at SHA.
Conclusions: Accurate knowledge of vertebral level of CMT, DST and SHA and the distances in-between might decrease the iatrogenic injury of dural sac, spinal cord and cauda equina
Myocardial bridge and coronary arteries: morphological study and clinical significance
Myocardial bridge (MB) is the myocardial bundles covering a segment of a coronary artery or one of its branches. This work aimed to study the morphological properties of MB and their effects on the structure of the dominant coronary artery. Sixty adult human hearts (40 male and 20 female) were obtained from the Anatomy Department, Faculty of Medicine, King Abdulaziz University. Dissection o fthe coronary arteries and their main branches was done. Number, site, length and thickness of MB were determined in correlation with coronary dominancy. External diameter of proximal and distal segments of bridged branches and histology of the different segments of the anterior interventricular artery were examined as well. Thirty-six MB were observed in 27 (45%) hearts (18 male and 9 female). MB were mostly observed on the middle segment of the anterior interventricular artery (52.8%) and to a lesser extent on its diagonal branch (13.8%), posterior interventricular artery (13.8%), median and left marginal branches (5.6%), and right coronary artery stem (2.8%). In 30% out of 56.7% of right, in 8.3% out of 26.7% of balanced and in 6.7% out of 16.7% of left dominant hearts revealed MB. The mean length of MB was 24.9 ± 1.98 mm and that of their thickness was 2.28 ± 0.13 mm. Morphological differences in external diameter and histological structure of the different parts of bridged branch were observed. Knowledge of morphological aspects and effects of MB provide better therapeutic and surgical interventions for clinicians dealing with patients having MB
The radial artery and its variations: anatomical study and clinical implications
Objectives: to describe the radial artery and its variants in origin, branching pattern, mode of termination, measurements of its length and external diameter.Methods: 100 upper limbs of 30 men & 20 women adult cadavers were used in this study. The cadavers were obtained from the Anatomy department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. The axillary region, arm, forearm and hand of each limb were dissected to clarify the course and branches of radial artery. This anatomical descriptive study was conducted between September, 2010 and August, 2012 after approval the ethical committee.Results: the mean distance of the normal origin of radial artery as one of two terminal branches of brachial artery was 38.7±9.5mm in men & 36.5±8.5mm in women upper limbs below the intercondylar line while, variant origin of radial artery was found in eight limbs. The mean of radial artery length was 226.2±21.7mm in men and 209.9 ±13.9 mm in women limbs and that of its external diameter was 3.3 ±0.7 mm in men & 3.2±0.66mm in women at 1 cm distal to its origin; 3.1±0.73 mm in men & 3.0±0.66 in women at 2cm proximal to styloid process of radius. The radial artery showed different branching patterns and three modes of termination.Conclusion: Knowledge of radial artery description and its variants has great importance in different clinical fields and basic medical studies
Morphology and clinical implication of the extra-head of biceps brachii muscle
The biceps brachii muscle is present in the anterior aspect of the arm. Its morphological variations have great clinical significance for surgeons, orthopaedic surgeons, anaesthetists, neurologists and anatomists. This study aimed to describe the incidence and morphology of the extra-heads of the biceps brachii muscle. Hundred upper limbs of 50 adult human cadavers (30 men and 20 women) were used in this study after the approval of the medical ethical committee. These cadavers were obtained from the Anatomy Department, Faculty of Medicine, King Abdul-Aziz University. The incidence of anatomical variations of biceps muscle was equal in both male and female cadavers (10%) with predominance of the left side (7%). The 3-headed biceps brachii muscle was noticed in 7% (4% male and 3% female), while the 4-headed biceps was seen in 2 (2%) left limbs, 1 male and 1 female. The third head of the biceps muscle arose from the anteromedial aspect of humerus, between the coracobrachialis insertion and the brachialis origin, in 6% and from middle of the medial border of humerus in 3%. While the fourth head originated from the articular capsule of shoulder joint in 1 (1%) limb and from the coracoid process of scapula in the other limb. The biceps common tendon of insertion received the supernumerary heads in 7% of the limbs. However, the extra-head fused with the long head in 2 (2%) limbs and united with the short head in 1 (1%) limb. The mean of the third head length was 118.8 ± 10.9 in all limbs, where it was 121.8 ± 12.3 in male and 113.5 ± 8.1 in female cadavers. The third head length/arm length ratio was 38.4 ± 2.6 in all, 38.3 ± 3.4 in male and 38.8 ± 1.8 in female cadavers. The length of the extra-head was extremely significant with those of the corresponding limb in all, male and female cadavers (p < 0.0001). Knowledge of the morphological variations of biceps muscle provides better pre-operative evaluation, safe surgical intervention within the arm and better postoperative outcomes
Measurements, processing functions and laboratory test-bed experiments for evaluating diversity in broadcast network
This paper presents a test-bed development and measurement plan for evaluating transmit diversity and on-channel repeaters in the Digital Video Broadcasting Network. Transmit diversity reduces the complexity and improves the power consumption of the personal receiving devices by enhancing the transmission of signals in NLOS cluttered environments. It is more practical than receive diversity due to the difficulty of locating two receive antennas far enough apart in a small mobile device. The on-channel repeater is to extend the coverage of the DVB-T/H network in areas where services are inaccessible by receiving the DVB-T/H signals off air, amplifying and then retransmitting it on the same frequency as received. Test service scenarios were developed to illustrate the benefits of such technologies so that effectiveness can be researched in a variety of service and terrain scenarios using purpose built test systems.The work presented in this paper was supported by the European Commission IST project PLUTO
Laboratory measurement campaign of DVB-T signal with transmit delay diversity
The requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed cost-effectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of Transmit Delay Diversity (DD) with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using a SPIRENT SR5500 dual channel emulator. The relationship between correlation coefficient between channels, receiver velocity and diversity gain is nvestigated. It is shown that transmit delay diversity significantly improves the quality of reception particularly in simulated fast fading mobile broadcasting applications. This paper documents research conducted by Brunel University and Broadreach Systems
Morphometric parameters and histological study of the filum terminale of adult human cadavers and magnetic resonance images
Background: Morphology and histology of filum terminale (FT) has a role in the pathophysiology of tethered cord syndrome (TCS). This research was implemented to investigate the morphometric parameters and histological structure of normal FT in adult human cadavers and magnetic resonance imaging (MRI) scans to correlate them with the pathophysiology of TCS.
Materials and methods: Twenty five adult human cadavers (15 males, 10 females) and 100 MRI echo scans of lumbosacral region (50 males and 50 females), were used in this study. MRI patients were divided into 21–40 and 41–60 age groups. The cadavers were dissected at the prone position to explore their fila. The length of FT, filum terminale internum (FTI), filum terminale externum (FTE), vertebral level of beginning, dural piercing and termination of FT, and the initial, midpoint, and mid-FTE diameters were determined. Four segments were excised from lower conus, upper, middle, and lower thirds of FT. The specimens were processed for light microscopic examination. Statistical analysis was done for these parameters.
Results: MRI morphometrical parameters of FT, except FTI length, revealed no age effect or sex differences, where length of FTI, FTE, initial diameter, level of conus medullaris termination (CMT) and dural sac termination (DST) were 174.1 ± 16.8, 75.8 ± 9.5, 1.6 ± 0.21, L1-2 and S2U in males and 166.9 ± 18.9, 74.1 ± 9.3, 1.53 ± 0.25, L1-2 and S2M vertebrae in females, respectively. However, non-significant sex difference was observed in morphometric parameters of cadaveric FT, where length of FTI and FTE, initial diameter, CMT and DST levels were 164.2 ± 11.6, 76.7 ± 8.1, 1.7 ± 0.14, L1L and S2U vertebrae in males and 159.2 ± 10.1, 71.02 ± 7.3, 1.6 ± 0.29, L1L and S2U in females, respectively. Moreover, CMT below L2 vertebra was seen in 5% of MRI scans and 8% of cadavers. Also, the initial diameter of FT > 2 mm was recorded in 7% of MRI and 8% of cadaveric cases. Histologically, the structure of FT showed gradual reduction in nervous, glial, and vascular tissues with converse increase in collagen content in FTE compared with those of FTI.
Conclusions: Knowledge of the morphometric parameters and the histological structure of FT are necessary for clinicians who dealing with diagnosis or treatment of tethered cord syndrome
Simple, sensitive and rapid determination of linifanib (ABT-869), a novel tyrosine kinase inhibitor in rat plasma by UHPLC-MS/MS
An overall model for sulfur self-retention in ash during coal particle combustion is developed in this paper. It is assumed that sulfur retention during char combustion occurs due to the reaction between SO2 and CaO in the form of uniformly distributed non-porous grains. Parametric analysis shows that the process of sulfur self-retention is limited by solid difussion through the non-porous product layer formed on the CaO grains and that the most important coal characteristics which influence sulfur self-retention are coal rank. content of sulfur forms. molar Ca/S ratio and particle radius. A comparison with the experimentally obtained values in a FB reactor showed that die model can adequately predict the kinetics of the process, the levels of the obtained values of the SSR efficiencies, as well as the influence of temperature and coal particle size.U radu je prikazan razvijeni model zadržavanja sumpora u pepelu tokom sagorevanja uglja. Pretpostavka modela je da se zadržavanje sumpora tokom sagorevanja koksnog ostatka odigrava usled reakcije SO2 i CaO koji je u obliku ravnomerno raspoređenih zrna. Parametarska analiza je pokazala da je proces zadržavanja sumpora kontrolisan difuzijom kroz formirani sloj čvrstog produkta na zrnima CaO, kao i da su rang uglja, sadržaj formi sumpora molarni Ca/S odnos i veličina čestice važne osobine uglja koje utiču na proces. Poređenje sa eksperimentalnim rezultatima dobijenim u reaktoru sa fluidizovanim slojem je pokazalo da model može adekvatno da predvidi kinetiku procesa, efikasnost zadržavanja sumpora u pepelu, kao i uticaj temperature i veličine čestice uglja
Systematic selection of small molecules to promote differentiation of embryonic stem cells and experimental validation for generating cardiomyocytes.
Small molecules are being increasingly used for inducing the targeted differentiation of stem cells to different cell types. However, until now no systematic method for selecting suitable small molecules for this purpose has been presented. In this work, we propose an integrated and general bioinformatics- and cheminformatics-based approach for selecting small molecules which direct cellular differentiation in the desired way. The approach was successfully experimentally validated for differentiating stem cells into cardiomyocytes. All predicted compounds enhanced expression of cardiac progenitor (Gata4, Nkx2-5 and Mef2c) and mature cardiac markers (Actc1, myh6) significantly during and post-cardiac progenitor formation. The best-performing compound, Famotidine, increased the percentage of Myh6-positive cells from 33 to 56%, and enhanced the expression of Nkx2.5 and Tnnt2 cardiac progenitor and cardiac markers in protein level. The approach employed in the study is applicable to all other stem cell differentiation settings where gene expression data are available.YK and AB thank the European Research Council (ERC Starting Grant 2013 to AB) for funding.This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/cddiscovery.2016.
ICH guidelines-compliant HPLC-UV method for pharmaceutical quality control and therapeutic drug monitoring of the multi-targeted tyrosine kinase inhibitor pazopanib
In this study, an HPLC method with ultraviolet (UV) detection was developed and validated for determination of pazopanib (PAZ), a multi-targeted tyrosine kinase (TK) inhibitor in bulk drug, tablets formulation, and in human plasma. Oxamniquine (OXA) was used as internal standard (IS). The analytical column used for the separation was Nucleosil CN with dimensions (i.d. 250 × 4.6 mm and particle size 5 μm). The separation was carried out in isocratic mode with mobile phase constituting acetonitrile:100 mM sodium acetate buffer (pH 4.5); 40:60, v/v. The developed method was linear in the concentration range of 2–12 μg mL–1 and had a correlation coefficient (r = 0.9998, n = 6). The limits of detection and quantitation (LOD and LOQ) were 0.27 and 0.82 μg mL–1, respectively. The relative standard deviations for the inter- and intra-assay precisions were below 3.61 % and the accuracy of the method was 96.69–104.15 %. The degradation products were resolved from the intact drug, proving the stability-indicating property of the proposed method. The recovery values were 100.17–103.98 % (± 1.81–4.02) for determination of PAZ in human plasma. The results indicated the versatility of the new method in estimation of PAZ during pharmaceutical quality control (QC) and therapeutic drug monitoring (TDM).Keywords: Tyrosine kinase inhibitors, pazopanib, HPLC, UV detection, quality control, therapeutic drug monitorin
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