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Injection Techniques (injection + techniques)
Selected AbstractsHigh-resolution DNA separation in microcapillary electrophoresis chips utilizing double-L injection techniquesELECTROPHORESIS, Issue 21-22 2004Lung-Ming Fu Abstract An experimental and numerical investigation into the use of high-resolution injection techniques to separate DNA fragments within electrophoresis microchips is presented. The principal material transport mechanisms of electrokinetic migration, fluid flow, and diffusion are considered, and several variable-volume injection methods are discussed. A detailed analysis is provided of a double-L injection technique, which employs appropriate electrokinetic manipulations to reduce sample leakage within the microchip. The leakage effect in electroosmotic flow (EOF) is investigated using a sample composed of rhodamine B and Cy3 dye. Meanwhile, the effects of sample leakage in capillary electrophoresis (CE) separation are studied by considering the separation of 100-base pairs (bp) DNA ladders and HaeIII-digested ,X-174 DNA samples. The present experimental and simulation results indicate that the unique injection system employed in the current microfluidic chip has the ability to replicate the functions of both the conventional cross-channel and the shift-channel injection systems. Furthermore, applying the double-L injection method to these two injection systems is shown to reduce sample leakage significantly. The proposed microfluidic chip and double-L injection technique developed in this study have an exciting potential for use in high-resolution, high-throughput biochemical analysis applications and in many other applications throughout the micrototal analysis systems field. [source] Vagal motor neurons in rats respond to noxious and physiological gastrointestinal distention differentiallyEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2002Xueguo Zhang Abstract Low-pressure gastrointestinal distention modulates gastrointestinal function by a vago-vagal reflex. Noxious visceral distention, as seen in an obstruction of the gastrointestinal tract, causes abdominal pain, vomiting and affective changes. Using single neuron recording and intracellular injection techniques, we characterized the neuronal responses of neurons in the dorsal motor nucleus of the vagus (DMNV) to low- and high-pressure distentions of stomach and duodenum. Low-pressure gastric distention inhibited the mean activity of the DMNV neurons whereas high-pressure gastric distention excited many neurons. Of 47 DMNV neurons, low-pressure gastric distention inhibited 39, excited four, and did not affect four neurons. High-pressure gastric distention inhibited 26, excited 20, and left one unaffected. Thirteen of the 39 DMNV neurons inhibited by low-pressure distention of the stomach reversed their response to excitation during high-pressure gastric distention. Among 47 DMNV neurons, low-pressure duodenal distention inhibited 30, excited 10, and did not affect the remaining seven neurons. High-pressure distention of the duodenum inhibited 25 and excited 22 neurons. Eight DMNV neurons inhibited by low-pressure duodenal distention were excited in early response to high-pressure distention of the duodenum. High-pressure duodenal distention caused an early excitation and late inhibition in the mean activity of the DMNV neurons while low-pressure duodenal distention only produced late inhibition. These results suggest that different reflexes are present between physiological distention and noxious stimulation of gastrointestinal tract. [source] Prevention and treatment of hepatitis C in injection drug usersHEPATOLOGY, Issue 5B 2002Brian R. Edlin 3180 18th St. Injection drug users constitute the largest group of persons infected with the hepatitis C virus (HCV) in the United States, and most new infections occur in drug users. Controlling hepatitis C in the U.S. population, therefore, will require developing, testing, and implementing effective prevention and treatment strategies for persons who inject drugs. Fortunately, a substantial body of research and clinical experience exists on the prevention and management of chronic viral diseases among injection drug users. The need to implement interventions to stop the spread of HCV among drug users is critical. The capacity of substance-use treatment programs need to be expanded to accommodate all who want and need treatment. Physicians and pharmacists should be educated in how to provide access to sterile syringes and to teach safe injection techniques, both of which are lifesaving interventions. The treatment of hepatitis C in drug users requires an interdisciplinary approach that brings together expertise in treating hepatitis and caring for drug users. Treatment decisions should be made individually by patients with their physicians, based on a balanced assessment of risks and benefits and the patient's personal values. Physicians should carefully assess, monitor, and support adherence and mental health in all patients, regardless of whether drug use is known or suspected. Research is needed to better understand how best to prevent and treat hepatitis C in substance users. In the meantime, substantial progress can be made if existing knowledge and resources are brought to bear. [source] Single stimulation of the posterior cord is superior to dual nerve stimulation in a coracoid blockACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010J. RODRÍGUEZ Background: Both multiple injection and single posterior cord injection techniques are associated with extensive anesthesia of the upper limb after an infraclavicular coracoid block (ICB). The main objective of this study was to directly compare the efficacy of both techniques in terms of the rates of completely anesthetizing cutaneous nerves below the elbow. Methods: Seventy patients undergoing surgery at or below the elbow were randomly assigned to receive an ICB after the elicitation of either a single radial nerve-type response (Radial group) or of two different main nerve-type responses of the upper limb, except for the radial nerve (Dual group). Forty milliliters of 1.5% mepivacaine was given in a single or a dual dose, according to group assignment. The sensory block was assessed in each of the cutaneous nerves at 10, 20 and 30 min. Block performance times and the rates of complete anesthesia below the elbow were also noted. Results: Higher rates of sensory block of the radial nerve were found in the Radial group at 10, 20 and 30 min (P<0.05). The rates of sensory block of the ulnar nerve at 30 min were 97% and 75% in the Radial and in the Dual groups, respectively (P<0.05). The rate of complete anesthesia below the elbow was also higher in the Radial group at 30 min (P<0.05). Conclusions: Injection of a local anesthetic after a single stimulation of the radial nerve fibers produced more extensive anesthesia than using a dual stimulation technique under the conditions of our study. [source] Structure of the human tibialis anterior tendonJOURNAL OF ANATOMY, Issue 4 2000WOLF PETERSEN The structure and vascular pattern of the human tibialis anterior tendon was investigated using injection techniques, light and transmission electron microscopy and immunohistochemistry. From the well vascularised peritenon, blood vessels penetrate the tendon tissue and anastomose with a longitudinally oriented intratendinous network. The distribution of blood vessels within the tibialis anterior tendon was not homogenous. The posterior part of the tendon had a complete vascular network that extends from the musculotendinous junction to the insertion at the first metatarsal and medial cuneiform bones. In the anterior half, the tissue was avascular in a zone with a length of 45,67 mm. This zone was covered by a single layer (,30 ,m) of oval shaped cells. Transmission electron microscopy showed that these cells have the characteristics of chondroid cells. This region was stained by Alcian blue at pH 1 which indicates a high concentration of acid glycosaminoglycans and immunohistochemical staining for chondroitin-4-sulphate, chondroitin-6-sulphate and aggrecan was positive. However, immunostaining for the typical cartilage specific type II collagen within this zone was negative. The location of the avascular zone corresponds to the region where the tibialis anterior tendon wraps around the superior and inferior retinacula which serve as fibrous pulleys. This is the region where most spontaneous ruptures of the tibialis anterior tendon occur. The presence of fibrocartilage within gliding tendons is a functional adaptation to compressive and shearing forces. In contrast to reports from the literature about the structure of gliding tendons wrapping around a bony pulley, the gliding zone of the tibialis anterior tendon has only a narrow layer of chondroid cells and proof of type II collagen is lacking. [source] The effect of vibration on pain during local anaesthesia injectionsAUSTRALIAN DENTAL JOURNAL, Issue 2 2009E Nanitsos Abstract Background:, The "gate control" theory suggests pain can be reduced by simultaneous activation of nerve fibres that conduct non-noxious stimuli. This study investigated the effects of vibration stimuli on pain experienced during local anaesthetic injections. Methods:, In a preliminary study, subjects were asked to rate anticipated and actual pain from regional anaesthetic injections in the oral cavity. A second study compared, within subjects, pain from injections with and without a simultaneous vibration stimulus. Both infiltration and block anaesthetic injection techniques were assessed. In each subject, two similar injections were given and with one, a vibration stimulus was randomly allocated. Injection pain was assessed by visual analogue scale and McGill pain descriptors. Results:, Both infiltration and block injections were painful (mean anticipated intensity: 31.25, actual: 17.82 mm on 100 mm scale). Pain intensity with and without vibration was 12.9 mm (range 0,67) and 22.2 mm (range 0,83) respectively (p = 0.00005, paired T-test), and this effect was seen with both infiltration (p = 0.032) and block anaesthetic (p = 0.0001) injection subgroups. Furthermore, compared to no vibration-stimulus injections, injections with vibration resulted in less pain descriptors chosen (p = 0.004), and the descriptors had a lower pain rating (p = 0.001). Conclusions:, The results suggest that vibration can be used to decrease pain during dental local anaesthetic administration. [source] Thoracic paravertebral spread using two different ultrasound-guided intercostal injection techniques in human cadaversCLINICAL ANATOMY, Issue 7 2010Tilemachos Paraskeuopoulos Abstract The continuity between the intercostal and paravertebral space has been established by several studies. In this study, the paravertebral spread of a colored dye was attempted with two different ultrasound-guided techniques. The posterior area of the trunk was scanned with a linear probe between the level of the fifth and the seventh thoracic vertebrae in eleven embalmed human cadavers. In the first technique, the probe was placed transversely below the inferior margin of the rib, and a needle was inserted between the internal intercostal membrane and the pleura. In the second technique, the probe was placed longitudinally at the intercostal space 5 cm lateral to the spinous processes, and the needle was inserted between the internal intercostal membrane and the pleura. In both techniques, 1 ml of methylene blue was injected, and both the intercostal and paravertebral spaces were prepared. In total, 33 injections were performed: 19 with the transverse technique and 14 with the longitudinal technique. Successful spread of the dye to the thoracic paravertebral space was recorded in 89.5% cases using the transverse technique and 92.8% cases using the longitudinal technique. No intrapleural spread of the dye was recorded in either technique. Ultrasound-guided injection into the intercostal space may offer an alternative approach to the thoracic paravertebral space. Clin. Anat. 23:840,847, 2010. © 2010 Wiley-Liss, Inc. [source] | |||||||||||||