Measurement of the edge plasma rotation on J-TEXT tokamak

A multi-channel high resolution spectrometer was developed for the measurement of the edge plasma rotation on J-TEXT tokamak. With the design of two opposite viewing directions, the poloidal and toroidal rotations can be measured simultaneously, and velocity accuracy is up to 1 km∕s. The photon flux was enhanced by utilizing combined optical fiber. With this design, the time resolution reaches 3 ms. An assistant software "Spectra Assist" was developed for implementing the spectrometer control and data analysis automatically. A multi-channel monochromatic analyzer is designed to get the location of chosen ions simultaneously through the inversion analysis. Some preliminary experimental results about influence of plasma density, different magnetohydrodynamics behaviors, and applying of biased electrode are presented.

Ligation of the intersphincteric fistula tract plus a bioprosthetic anal fistula plug (LIFT-Plug): a new technique for fistula-in-ano

AIM

Ligation of the intersphincteric fistula tract and reinforcement with a bioprosthetic graft are two recently reported procedures that have shown promise in the treatment of anal fistula. This study was undertaken to validate combining ligation of the intersphincteric fistula tract plus bioprosthetic anal fistula plug and report our preliminary results and experience.

METHOD

Twenty-one patients with transsphincteric anal fistula were treated with ligation of the intersphincteric fistula tract plus concurrent bioprosthetic plug of the anal fistula. We evaluated healing time, fistula closure rate and postoperative anal function according to the Wexner continence score.

RESULTS

No mortality or major complications were observed. Median operative time was 20 (range 15-40) min. After a median follow-up of 14 (range 12-15) months, the overall success rate was 95% (20/21), with a median healing time of 2 (range 2-3) weeks for external anal fistula opening and 4 (range 3-7) weeks for intersphincteric groove incision. Only 1 (5%) patient reported rare incontinence for gas postoperatively (Wexner score 1).

CONCLUSIONS

Ligation of the intersphincteric fistula tract plus a bioprosthetic anal fistula plug is an easy, safe, effective and useful alternative in the management of anal fistula. Further randomized controlled studies are necessary to better evaluate long-term results.

Co-transfection of adeno-associated virus-mediated human vascular endothelial growth factor165 and transforming growth factor-β1 into annulus fibrosus cells of rabbit degenerative intervertebral discs

Intervertebral disc degeneration is a common condition that may lead to low back pain and radiculopathy. Understanding the pathophysiology and cellular and molecular events of degenerative disc disease has resulted in the proposal of a gene therapy approach to halt and reverse disc degeneration. We explored the feasibility of reversing intervertebral disc degeneration using human vascular endothelial growth factor165 (hVEGF165) and transforming growth factor-β1 (TGF-β1) gene therapy. hVEGF165 complementary DNA was obtained from pcDNA3(+)-hVEGF165 and cloned into adeno-associated virus (AAV)-pSNAV plasmids to construct the recombinant plasmid, AAV-pSNAV-hVEGF165. After identification through restriction enzyme digestion and DNA sequencing, the AAV-pSNAV-hVEGF165 was transfected into HEK293 cells and vascular endothelial cells. Protein expression of hVEGF165 was detected using a fluorescent immunohistochemical assay, and the effect of hVEGF165 on vascular endothelial cell proliferation was determined with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Packaged AAV-hVEGF165 and AAV-TGF-β1 were co-transfected into the annulus fibrosus cells of degenerative intervertebral discs. hVEGF165 and TGF-β1 expression by annulus fibrosus cells and the effect of the co-transfection on the level of collagen type I protein expression by annulus fibrosus cells were detected with Western blot. The results of restriction enzyme digestion and DNA sequencing confirmed that AAV-pSNAV-hVEGF165 plasmids were constructed. The fluorescent immunohistochemical results confirmed hVEGF165 protein expression. The MTT results showed that the hVEGF165 protein promoted vascular endothelial cell proliferation. Biologically active AAV-hVEGF165 and AAV-TGF-β1 were successfully constructed. Western blot confirmed hVEGF165 and TGF-β1 expression in annulus fibrosus cells and demonstrated that the level of collagen type I protein expression was significantly higher in annulus fibrosus cells co-transfected with both AAV-hVEGF165 and AAV-TGF-β1 compared with that in cells transfected with AAV-hVEGF165 or AAV-TGF-β1 alone. hVEGF165 has a synergistic effect with TGF-β1 that promotes the expression of collagen type I protein in annulus fibrosus cells from degenerative intervertebral discs.

Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

BACKGROUND

Nonspecific (nonproductive) binding (adsorption) of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) is a relatively new process, but demonstrated robust performance for sugar and biofuel production from woody biomass especially softwoods in terms of yields and energy efficiencies. This study demonstrated the role of lignin sulfonation in enhancing enzymatic saccharification of lignocelluloses - lignosulfonate from SPORL can improve enzymatic hydrolysis of lignocelluloses, contrary to the conventional belief that lignin inhibits enzymatic hydrolysis due to nonspecific binding of cellulase.

RESULTS

The study found that lignosulfonate from SPORL pretreatment and from a commercial source inhibits enzymatic hydrolysis of pure cellulosic substrates at low concentrations due to nonspecific binding of cellulase. Surprisingly, the reduction in enzymatic saccharification efficiency of a lignocellulosic substrate was fully recovered as the concentrations of these two lignosulfonates increased. We hypothesize that lignosulfonate serves as a surfactant to enhance enzymatic hydrolysis at higher concentrations and that this enhancement offsets its inhibitive effect from nonspecific binding of cellulase, when lignosulfonate is applied to lignocellulosic solid substrates. Lignosulfonate can block nonspecific binding of cellulase by bound lignin on the solid substrates, in the same manner as a nonionic surfactant, to significantly enhance enzymatic saccharification. This enhancement is linearly proportional to the amount of lignosulfonate applied which is very important to practical applications. For a SPORL-pretreated lodgepole pine solid, 90% cellulose saccharification was achieved at cellulase loading of 13 FPU/g glucan with the application of its corresponding pretreatment hydrolysate coupled with increasing hydrolysis pH to above 5.5 compared with only 51% for the control run without lignosulfonate at pH 5.0. The pH-induced lignin surface modification at pH 5.5 further reduced nonspecific binding of cellulase by lignosulfonate.

CONCLUSIONS

The results reported in this study suggest significant advantages for SPORL-pretreatment in terms of reducing water usage and enzyme dosage, and simplifying process integration, i.e., it should eliminate washing of SPORL solid fraction for direct simultaneous enzymatic saccharification and combined fermentation of enzymatic and pretreatment hydrolysates (SSCombF). Elevated pH 5.5 or higher, rather than the commonly believed optimal and widely practiced pH 4.8-5.0, should be used in conducting enzymatic saccharification of lignocelluloses.

Takayasu arteritis: imaging spectrum at multidetector CT angiography

Takayasu arteritis is a chronic, idiopathic, inflammatory disease that primarily affects large vessels, such as the aorta and its major branches and the pulmonary and coronary arteries. The non-specific inflammation of involved vessels usually leads to concentric wall thickening, fibrosis and thrombus formation. Diseased arteries become stenotic or occluded, undergo vascular remodelling or develop aneurysms. According to the involvement of arteries, six types of Takayasu arteritis are documented. The purpose of this pictorial review is to illustrate the various multidetector CT angiography appearances of Takayasu arteritis and to discuss the differential diagnosis.

A 16-channel heterodyne electron cyclotron emission radiometer on J-TEXT

To study equilibrium temporal dynamics and the mechanisms of magnetohydrodynamic instabilities, a 16-channel heterodyne electron cyclotron emission (ECE) radiometer has been developed to view the J-TEXT tokamak from the low field side. The ECE radiometer detects second-harmonic extraordinary mode in the frequency band of 94-125 GHz which corresponds to resonances from 1.8 T to 2.2 T. This ECE system consists of an ECE transmission line, a radio frequency unit, and two 8-channel intermediate frequency units. An in situ blackbody calibration source is applied for system calibration by comparison of hot and cold sources in order to provide an absolute temperature measurement.

First results from the J-TEXT high-resolution three-wave polarimeter-interferometer

A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1°, at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is ∼1 μs. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.

Vibration mitigation in J-TEXT far-infrared diagnostic systems

Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.

Tangential x-ray imaging crystal spectrometer on J-TEXT tokamak

A tangential x-ray imaging crystal spectrometer (XICS) has been developed for the J-TEXT tokamak to measure the ion temperature and the plasma toroidal rotation velocity. The resonance spectral line and its satellites of Ar XVII in the ranges of 3.94 Å-4.0 Å are detected. A spherically bent quartz crystal with 2d = 4.913 Å is used in this system. The crystal has a dimension of 9 cm high and 3 cm wide and the radius of curvature 3823 mm. The XICS is designed to receive emission of Ar XVII from -10 cm to +10 cm region with a spatial resolution of 3.1 cm in the vertical direction considering the parameters of the J-TEXT plasma. The XICS has a tangential angle of 27° with respect to toroidal direction in the magnetic axis. A two-dimensional 100 mm by 300 mm multi-wire proportional counter is applied to detect the spectra.

Note: measurement of the runaway electrons in the J-TEXT tokamak

The runaway electrons have been measured by hard x-ray detectors and soft x-ray array in the J-TEXT tokamak. The hard x-ray radiations in the energy ranges of 0.5-5 MeV are measured by two NaI detectors. The flux of lost runaway electrons can be obtained routinely. The soft x-ray array diagnostics are used to monitor the runaway beam generated in disruptions since the soft x-ray is dominated by the interaction between runaway electrons and metallic impurities inside the plasma. With the aid of soft x-ray array, runaway electron beam has been detected directly during the formation of runaway current plateau following the disruptions.

Isolation, sequence analysis, and characterization of androgen receptor in Southern catfish, Silurus meridionalis

Androgen receptor (AR), the mediator of androgen, plays important roles in the androgen signal pathway. In the present study, we isolated and analyzed the cDNA sequence and tissue distribution of androgen receptor in Southern catfish (scAR). The full-length cDNA of scAR contains 3,116 bp with an open reading frame (ORF) of 2,415 bp, encoding a protein of 804 amino acids (aa). Tissue distribution analysis of scAR revealed that it was expressed in all tissues examined, with no sexual dimorphism in the ovary and testis. Phylogenetic analysis and multiple amino acids sequence alignment indicated the close relationship and high similarity of scAR with ARs from cypriniform species. In addition, partial sequences of ARs from 7 other siluriform species were also isolated. Comparison of catfish ARs with those from other vertebrates revealed that an extra C-terminal tail of about 20aa exists in all the ARs from siluriform fishes investigated, but not in other ARs. The extra sequence was resulted from a 4-bp insertion before the stop codon of other vertebrate ARs, and it was identical in ARs from siluriform species of the same genus but different among ARs from species of different genera. We report here for the first time that the ARs from siluriform species are longer in C-terminal than those from other vertebrates and it might be useful in reconstruction of the phylogenetic relationship among siluriform fishes. The significance of the extra C-terminal tail for AR function remains elusive.

Presence of neuropathic pain as an underlying mechanism for pain associated with cold weather in patients with sickle cell disease

Less than 20 years after Herrick described the first case, the cold was proposed as having a role in precipitating pain in sickle cell disease. Numerous publications focus on weather changes, in particular exposure to the cold, and their association with vaso-occlusive (painful) episodes. Whereas several theories have been proposed to explain the association, a plausible hypothesis based on our current understanding of the pathophysiology of pain has not been offered. We hypothesize that the pain evoked by these weather changes are allodyinic (pain with stimulus not typically painful) and hyperalgesic (heightened pain with painful stimulus) responses due to the presence of neuropathic pain. This hypothesis represents a paradigm shift in understanding, as well as explaining at least some of the pain experience in sickle cell disease, and should be the impetus to further determine the characteristics of those patients who develop allodynia and hyperalgesia to cold weather. Whereas some researchers have suggested that those with sickle cell disease may have neuropathic pain, including a report from our own ongoing study [1], it has not been well accepted nor has it been applied in understanding pain associated with sickle cell disease. The conceptual shift and new understanding is important to develop preventive strategies, apply pain therapies new to the sickle cell population, and view pain in sickle cell disease in the context of a chronic disease.

Design of far-infrared three-wave polarimeter-interferometer system for the J-TEXT tokamak

A multichannel three-wave far-infrared polarimeter-interferometer will be constructed on the J-TEXT tokamak (R=1.05 m, a=0.27 m, B(T)≤3 T, and I(P)≤350 kA) for current density profile and electron density profile measurements. The system will adopt the three-wave polarimeter configuration which was first introduced on RTP. Three 432.5 μm HCOOH lasers pumped by three CO(2) lasers separately will be adopted, which could generate high output power, nearly 50 mW at each cavity. Two of them will be counter-rotating circularly polarized to probe the Faraday angle, while the third laser will be used as a local oscillator to get the phase shift caused by electron density. Excellent port access (600×76 mm(2)) and high laser power would promise a profile measurement across the whole plasma section with good signal quality. A high-speed digital phase comparator with a few (∼2) μs temporal resolution will be developed, so that fast changes of current or density profile could be measured. Six channels will be installed in the first stage.

Imaging malignant and apparent malignant transformation of benign gynaecological disease

Common benign gynaecological diseases, such as leiomyoma, adenomyosis, endometriosis, and mature teratoma, rarely undergo malignant transformation. Benign transformations that may mimic malignancy include benign metastasizing leiomyoma, massive ovarian oedema, decidualization of endometrioma, and rupture of mature teratoma. The aim of this review is to provide a contemporary overview of imaging findings in malignant and apparent malignant transformation of benign gynaecological disease.

α-Galactosylceramide protects mice from lethal Coxsackievirus B3 infection and subsequent myocarditis

Myocarditis is an inflammation of the myocardium which often follows virus infections. Coxsackievirus B3 (CVB3), as a marker of the enterovirus group, is one of the most important infectious agents of virus-induced myocarditis. Using a CVB3-induced myocarditis model, we show that injection α-galactosylceramide (α-GalCer), a ligand for invariant natural killer (NK) T (iNK T) cells, can protect the mice from viral myocarditis. After the systemic administration of α-GalCer in CVB3 infected mice, viral transcription and titres in mouse heart, sera and spleen were reduced, and the damage to the heart was ameliorated. This is accompanied by a better disease course with an improved weight loss profile. Compared with untreated mice, α-GalCer-treated mice showed high levels of interferon (IFN)-γ and interleukin (IL)-4, and reduced proinflammatory cytokines and chemokines in their cardiac tissue. Anti-viral immune response was up-regulated by α-GalCer. Three days after CVB3 infection, α-GalCer-administered mice had larger spleens. Besides NK T cells, more macrophages and CD8(+) T cells were found in these spleens. Upon stimulation with phorbol myristate acetate plus ionomycin, splenocytes from α-GalCer-treated mice produced significantly more cytokines [including IFN-γ, tumour necrosis factor-α, IL-4 and IL-10] than those from untreated mice. These data suggest that administration of α-GalCer during acute CVB3 infection is able to protect the mice from lethal myocarditis by local changes in inflammatory cytokine patterns and enhancement of anti-viral immune response at the early stage. α-GalCer is a potential candidate for viral myocarditis treatment. Our work supports the use of anti-viral treatment early to reduce the incidence of virus-mediated heart damage.

A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges

A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

Patient-reported outcomes: descriptors of nociceptive and neuropathic pain and barriers to effective pain management in adult outpatients with sickle cell disease

Despite frequent episodes of severe recurrent pain in sickle cell disease (SCD), sensory pain in outpatient adults with SCD lacks sufficient characterization. Furthermore, pivotal barriers may interfere with these patients' adherence to prescribed analgesic therapies but have not been studied systematically. We describe sensory pain characteristics, barriers, and analgesic use reported by adults with SCD during routine clinic visits. Patients (N = 145; 67% female, 94% African American) completed measures on a pen-tablet computer. Patients reported an average of 3.6 +/- 2.3 pain sites; mean current pain intensity (3.3 +/- 3.2), least (3.0 +/- 2.7) and worst (4.9 +/- 3.5) pain intensity in 24 hours on a 0 to 10 scale, multiple neuropathic (4.5 +/- 3.4, 8.3% selected none) and nociceptive (6.8 +/- 4.0) pain descriptors, and continuous pain pattern (59%). Their mean pain barriers score was 2.2 +/- 0.9, and 33% were dissatisfied with their pain levels. Only 14% reported taking at least 1 adjuvant drug, 82% were taking nonopioids, 85% step 2 opioids, and 65% step 3 opioids. Patients reported using, on average, 4.9 +/- 2.7 analgesics. Their pain barriers scores were similar to or greater than people with cancer. Importantly, their pain may be both nociceptive and neuropathic, contrary to common expectations that SCD pain is only nociceptive. Few patients, however, took drugs effective for neuropathic pain.

Neurobiological mechanisms of pain in sickle cell disease

Pain is a frequent complaint of people living with sickle cell disease (SCD); however, the neurobiology of pain in SCD remains poorly understood. Whereas this pain has been thought to be primarily related to visceral and somatic tissue injury subsequent to vaso-occlusion events, emerging evidence from human and animal studies has suggested that a component of SCD pain may be related to neuropathic processes. Significant knowledge has been obtained from studies of molecular and neurobiological mechanisms leading to and maintaining neuropathic pain. Some of the most promising evidence has implicated major roles of protein kinase C and Ca2+/calmodulin-dependent protein kinase II, and their interaction with the N-methyl-D-aspartate receptors and the transient receptor potential vanilloid 1 receptor in the development of neuropathic pain. The latest evidence from our studies suggests that these pathways are important for SCD pain as well. Coupled with emerging animal models of SCD pain, we can now start to elucidate neurobiological mechanisms underlying pain in SCD, which may lead to better understanding and effective therapies.

First molecular detection of group A rotaviruses in drinking water sources in Beijing, China

The most prevalent group A rotavirus found in the diarrheic children was also determined in drinking water sources including raw water, treated water and tap water in Beijing, and then the possible contamination contributions to tap water for human consumption were discussed in this study. A total of 26 raw water samples, 77 treated water samples and 143 tap water samples in Beijing were collected for analysis of group A rotavirus from April 2006 to August 2007. According to the results, it was shown that group A rotaviruses occurred in 9 raw water samples (34.6%), 9 treated water samples (11.7%) and 32 tap water samples (22.4%) during the sampling period, and low disinfectant residuals or a vulnerability of the distribution system to pressure transients, in addition to raw water, may account for the group A rotaviruses contamination to tap water. The rotavirus contamination observed in this study may highlight a potential public health risk and illustrate the importance of including routine virological analysis of drinking water supplies during winter time in Beijing.

Pharmacokinetics and bioavailability of cefquinome in healthy piglets

A study on bioavailability and pharmacokinetics of cefquinome in piglets was conducted after intravenous (i.v.) and intramuscular (i.m.) administrations of 2.0 mg/kg of body weight, respectively. Plasma concentrations were measured by high-performance liquid chromatography assay with UV detector at 268-nm wavelength. Plasma concentration-time data after i.v. administration were best fit by a two-compartment model. The pharmacokinetic values were distribution half-life 0.27 +/- 0.21 h, elimination half-life 1.85 +/- 1.11 h, total body clearance 0.26 +/- 0.08 L/kg.h, area under curve 8.07 +/- 1.91 microg x h/mL and volume of distribution at steady state 0.46 +/- 0.10 L/kg. Plasma concentration-time data after i.m. administration were also best fit by a two-compartment model. The pharmacokinetic parameters were distribution half-life 0.88 +/- 0.42 h, elimination half-life 4.36 +/- 2.35 h, peak concentration 4.01 +/- 0.57 microg/mL and bioavailability 95.13 +/- 9.93%.

Diffusion tensor imaging of acute mild traumatic brain injury in adolescents

BACKGROUND

Despite normal CT imaging and neurologic functioning, many individuals report postconcussion symptoms following mild traumatic brain injury (MTBI). This dissociation has been enigmatic for clinicians and investigators.

METHODS

Diffusion tensor imaging tractography of the corpus callosum was performed in 10 adolescents (14 to 19 years of age) with MTBI 1 to 6 days postinjury with Glasgow Coma Scale score of 15 and negative CT, and 10 age- and gender-equivalent uninjured controls. Subjects were administered the Rivermead Post Concussion Symptoms Questionnaire and the Brief Symptom Inventory to assess self-reported cognitive, affective, and somatic symptoms.

RESULTS

The MTBI group demonstrated increased fractional anisotropy and decreased apparent diffusion coefficient and radial diffusivity, and more intense postconcussion symptoms and emotional distress compared to the control group. Increased fractional anisotropy and decreased radial diffusivity were correlated with severity of postconcussion symptoms in the MTBI group, but not in the control group.

CONCLUSIONS

In adolescents with mild traumatic brain injury (MTBI) with Glasgow Coma Scale score of 15 and negative CT, diffusion tensor imaging (DTI) performed within 6 days postinjury showed increased fractional anisotropy and decreased diffusivity suggestive of cytotoxic edema. Advanced MRI-based DTI methods may enhance our understanding of the neuropathology of TBI, including MTBI. Additionally, DTI may prove more sensitive than conventional imaging methods in detecting subtle, but clinically meaningful, changes following MTBI and may be critical in refining MTBI diagnosis, prognosis, and management.

Brain metabolite levels assessed by lactate-edited MR spectroscopy in premature neonates with and without pentobarbital sedation

BACKGROUND AND PURPOSE

Pentobarbital is known to affect cerebral metabolism; pentobarbital sedation is, however, frequently used for MR imaging and MR spectroscopy, especially in children. Accurate assessment of the brain metabolite levels is important, particularly in neonates with suspected brain injury. We investigated whether pentobarbital sedation has any effect on the ratios of spectral metabolites lactate, N-acetylaspartate, or choline in a group of premature neonates.

MATERIALS AND METHODS

MR spectroscopy was performed in 43 premature neonates, all with normal concurrent MR imaging and normal neurodevelopmental outcome at 12 months of age. Of those neonates, 14 (33%) required pentobarbital (Nembutal 1 mg/kg) sedation during MR spectroscopy; the remaining 29 neonates did not receive any sedation. Ratios of lactate, choline, and N-acetylaspartate were calculated in the basal ganglia, thalami, and corticospinal tracts and compared between those neonates with and without sedation.

RESULTS

Small amounts of brain lactate were detected in all of the premature neonates. The basal ganglia lactate/choline and lactate/N-acetylaspartate ratios were significantly lower, by 17% and 25% respectively, in the neonates with pentobarbital sedation compared with the age-matched neonates without sedation (P < .05). Sedation did not affect the lactate level in the thalami or the corticospinal tracts. The N-acetylaspartate/choline ratios were unaffected by pentobarbital sedation.

CONCLUSION

Pentobarbital sedation is associated with lower lactate/choline and lactate/N-acetylaspartate ratios in the basal ganglia of premature neonates, as determined by proton MR spectroscopy. Investigators should be aware of this phenomenon for accurate interpretation of their MR spectroscopy results.

Pharmacokinetics and bioavailability of imidocarb dipropionate in swine

A two-way crossover study was performed in eight healthy young pigs to determine the pharmacokinetics of imidocarb dipropionate (IMDP) following intravenous (2 mg/kg b.w.) and intramuscular (2 mg/kg b.w.) administrations. Each animal received one intravenous and one intramuscular injection with a 30-day washout period between the two-treatments. Plasma concentrations were measured by high-performance liquid chromatography (HPLC) assay with UV detector at regular intervals for up to 24 h post-injection. Intravenous plasma concentration profiles best fit a three-compartmental model yielding a mean system clearance (Cl((s))) of 558 mL/kg.h and a mean half-life of 13.91 h. Mean imidocarb AUC((0-infinity)) (microg.h/mL), V(c) (L/kg), V(d(area))(L/kg) and MRT((0-t)) (h) values were 3.58, 0.11, 14.36 and 1.46, respectively. Compartmental modeling of imidocarb, after intramuscular administration produced best fit for two-compartmental model yielding mean Kalpha (h(-1)), Cmax (microg/mL), tmax (h), and bioavailability (%) of 3.89, 2.02, 0.54, and 86.57 for the 2 mg/kg dose level. The present studies showed that IMDP was rapidly absorbed, widely distributed, and slowly eliminated. No adverse effects were observed in any of the pigs after i.v. and i.m. administrations of IMDP. The favorable PK behavior, such as the long half-life, acceptable bioavailability indicated that it is likely to be effective in pigs.