Chicken embryonic brain: an in vivo model for verifying neural stem cell potency

OBJECT

The multipotency of neural stem cells (NSCs) can be assessed in vitro by detection of stage-specific markers in response to a suitable differentiation signal. This test is frequently used because it is fast and affordable. However, it is not clear how the in vitro potential for multilineage differentiation and stem cell marker expression would reflect the ability of NSCs to engraft into the brain following transplantation. The authors undertook this study to directly compare the in vitro potency and in vivo migration of human NSCs (hNSCs) expanded under conditions of gradually increased concentration of fetal bovine serum (FBS) as a maturation factor.

METHODS

Human NSCs isolated from fetal brain were propagated in serum free media (SF-hNSCs) and in media containing 0.1% and 0.2% serum. At Passage 4 in tissue culture the NSCs were harvested and either differentiated in vitro or transplanted into the lateral ventricle of chicken embryonic brain at the late stage of its development (Hamburger and Hamilton Stage 26). The in vitro differentiation was evaluated by immunostaining with neural or glial specific markers, and the in vivo migration was assessed using immunohistology.

RESULTS

The authors found that SF-hNSCs successfully engrafted into the chicken embryonic brain, which correlated with their ability to differentiate in vitro. NSCs grown at as low as 0.1% concentration of FBS failed to demonstrate the robust in vivo migration pattern but still preserved the capability to differentiate in vitro. Furthermore, NSCs generated in media containing a higher concentration of FBS (0.2%) lost both the in vivo engraftment and in vitro differentiation potential.

CONCLUSIONS

The present study suggests that marker expression and in vitro differentiation assays might not provide adequate information regarding the behavior of NSCs following their transplantation. The in vivo migration following injection into chicken embryonic brain may provide an important assay of the potency of NSCs.

Field induced dynamic waveguides based on potassium tantalate niobate crystals

In this paper, a new type of optical waveguide based on potassium tantalate niobate (KTN) electro-optic crystal is presented. The guiding property of the optical waveguide can be quickly (on the order of nanosecond) tuned and controlled by the applied external electric field, which can be useful for many applications such as broadband ultrafast optical modulators, variable optical attenuators, and dynamic gain equalizers.

The protective effect of curcumin on ischemia-reperfusion-induced liver injury

OBJECTIVE

Reperfusion of the ischemic liver results in the generation of oxidative and nitrosative stresses and reaction product of peroxynitrite, which induce rapid cytotoxicity and liver injury. In this study we demonstrated that curcumin, an antioxidant, attenuated ischemia/reperfusion (I/R)-induced liver injury.

MATERIALS AND METHODS

Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 30 minutes. Thereafter, flow was restored and the liver was reperfused for 80 minutes. Blood samples collected prior to ischemia and after reperfusion were analyzed for methyl guanidine (MG), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and adenosphate triphosphate (ATP). Blood levels of serum glutamic oxaloacetic transaminase (sGOT), serum glutamate pyruvate transaminase (sGPT), and lactic dehydrogenase (LDH), which served as indexes of liver injury, were measured.

RESULTS

The protocol resulted in elevation of blood NO (P < .001), TNF-α (P < .001), and MG (P < .001). sGOT, sGPT, and LDH were elevated significantly (P < .001), whereas ATP was significantly diminished (P < .001). Pretreatment with curcumin (25 mg/kg) significantly attenuated the reperfusion liver injury, while the ATP content reversed. In addition, MG, TNF-α, and NO release were attenuated.

CONCLUSIONS

These results indicated that curcumin exerted potent anti-inflammatory effects in I/R-induced liver injury due to its antioxidant effects.

Spots and stripes: pleomorphic patterning of stem cells via p-ERK-dependent cell chemotaxis shown by feather morphogenesis and mathematical simulation

A key issue in stem cell biology is the differentiation of homogeneous stem cells towards different fates which are also organized into desired configurations. Little is known about the mechanisms underlying the process of periodic patterning. Feather explants offer a fundamental and testable model in which multi-potential cells are organized into hexagonally arranged primordia and the spacing between primordia. Previous work explored roles of a Turing reaction-diffusion mechanism in establishing chemical patterns. Here we show that a continuum of feather patterns, ranging from stripes to spots, can be obtained when the level of p-ERK activity is adjusted with chemical inhibitors. The patterns are dose-dependent, tissue stage-dependent, and irreversible. Analyses show that ERK activity-dependent mesenchymal cell chemotaxis is essential for converting micro-signaling centers into stable feather primordia. A mathematical model based on short-range activation, long-range inhibition, and cell chemotaxis is developed and shown to simulate observed experimental results. This generic cell behavior model can be applied to model stem cell patterning behavior at large.

Self-organizing CMAC control for a class of MIMO uncertain nonlinear systems

This paper presents a self-organizing control system based on cerebellar model articulation controller (CMAC) for a class of multiple-input-multiple-output (MIMO) uncertain nonlinear systems. The proposed control system merges a CMAC and sliding-mode control (SMC), so the input space dimension of CMAC can be simplified. The structure of CMAC will be self-organized; that is, the layers of CMAC will grow or prune systematically and their receptive functions can be automatically adjusted. The control system consists of a self-organizing CMAC (SOCM) and a robust controller. SOCM containing a CMAC uncertainty observer is used as the principal controller and the robust controller is designed to dispel the effect of approximation error. The gradient-descent method is used to online tune the parameters of CMAC and the Lyapunov function is applied to guarantee the stability of the system. A simulation study of inverted double pendulums system and an experimental result of linear ultrasonic motor motion control show that favorable tracking performance can be achieved by using the proposed control system.

Intracranial pressure fluctuation during hemodialysis in renal failure patients with intracranial hemorrhage

Coagulopathy in renal failure patients often makes them vulnerable to intracranial hemorrhage. Emergency decompression to remove the hematoma and to stop bleeding is always indicated. After the surgery, hemodialysis (HD) should be arranged to maintain the BUN/Cr. level, and I/O balance. During HD, intracranial pressure in all of the patients in this study fluctuated. This phenomenon always resulted in neurological deterioration in acute or chronic renal failure. We present intracranial pressure (ICP) changes during HD in five acute or chronic renal failure patients with intracranial hemorrhage. They all underwent craniectomy or craniotomy with ICP monitors implantation. Different HD protocols were arranged for these patients and then we observed clinical results. ICP elevated during HD and resulted in severe brain swelling. This situation was one of the clinical presentations of dialysis disequilibrium syndrome (DDS). Four patients died because of this complication and one survived. ICP fluctuation seemed to be correlated with the fluid amount and frequency of HD. The prevalence and pathophysiology of DDS remain unclear. Renal failure patient with intracranial hemorrhage may be complicated with DDS when HD was performed. An attempt to reduce the fluid amount and to increase the frequency of HD might help these patients.

Redshift of edge emission from AlGaInP light-emitting diodes and correlation with electron-hole recombination lifetime

The edge emission from AlGaInP light-emitting diodes showed a red-shifted peak in addition to the peak of surface emission. This shift resulted from the quantum-well absorption of the guided wave. Although the shift degrades the color quality and the extraction efficiency of the device, it helps elucidate many important optical properties of the material and the dynamics of carrier recombination, including the electron-hole recombination lifetime, the optical joint density of state, the spontaneous emission spectrum and the absorption spectrum. A simple concept of the bimolecular recombination is established. The corresponding coefficient can be expressed by a simple formula and was therefore determined.

Joint effects of N-terminal pro-B-type-natriuretic peptide and C-reactive protein vs angiographic severity in predicting major adverse cardiovascular events and clinical restenosis after coronary angioplasty in patients with stable coronary artery disease

BACKGROUND

This study was designed to evaluate the joint effects of plasma C-reactive protein (CRP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) vs coronary angiographic severity on cardiovascular risk stratification.

METHODS AND RESULTS

A total of 345 patients with stable coronary artery disease (CAD) were recruited after successful percutaneous coronary intervention (PCI). Endpoints were major adverse cardiovascular events (MACE) and cumulative clinical restenosis rate after 18-36-month follow-up. Plasma NT-proBNP and CRP levels were among the strongest predictors of MACE. Adjusted hazard ratios of MACE according to combined biomarkers were 2.4 (p=0.05) for elevated CRP only, 5.22 (p<0.001) for elevated NT-proBNP only, and 7.04 (p<0.001) for elevation of both. The differential capacity using both plasma CRP and NT-proBNP in a receiver-operating-characteristics curve analysis (area under curve, AUC: 0.82) was significantly higher than using either biomarker alone or conventional risk factors (AUC: 0.67). Significant predictors of clinical restenosis were plasma NT-proBNP and the Gensini score. The combination of NT-proBNP and the Gensini score was the strongest predictor (AUC: 0.77) for clinical restenosis.

CONCLUSIONS

Plasma NT-proBNP, CRP, and the Gensini score are complementary in risk stratification. Combined use of these biomarkers has provided substantial extra information to conventional risk factors in stable CAD patients.

Hypofractionated CyberKnife stereotactic radiosurgery for acoustic neuromas with and without association to neurofibromatosis Type 2

CyberKnife stereotactic radiosurgery (CKSRS) has been proved effective in treating intra-cranial lesions. To treat acoustic neuroma (AN) patients with or without neurofibromatosis Type 2 (NF2) associations, the functional preservation of hearing, trigeminal nerve, and facial nerve are important. Twenty-one patients were treated with hypofractionated CKSRS. Fourteen non-NF2 and seven NF2 patients were enrolled. Cranial nerve function, audiograms, and magnetic resonance images (MRI) were monitored. Mean follow-up was 15 month. Tumors with volumes ranging from 0.13 to 24.8 cm3 (mean 5.4 cm3) were irradiated with the marginal dose 1800-2000 cGy/3 fractions. Tumors were treated with an 80 to 89% isodose line (mean 83%) and mean 97.9% tumor coverage. Two patients experienced hearing deterioration (16.7%) in the non-NF2 group, and 3 patients (50%) in the NF2 group. No facial or trigeminal dysfunction, brain stem toxicity, or cerebellar edema occurred. Tumor regression was seen in 9 patients (43%) and stable in 12 patients (57%). 100% tumor control rate was achieved. Hypofractionated CKSRS was not only effective in tumor control but also excellent in hearing preservation for non-NF2 AN. But for NF2 patients, although the tumor control was remarkable, hearing preservation was modest as in non-NF2 patients.

Evaluation of optimal cerebral perfusion pressure in severe traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability. In the 2000 guidelines, one of the suggestions for TBI treatment was to maintain cerebral perfusion pressure (CPP) < or = 70 mmHg. But in the 2003 guidelines, the suggestion was changed to < or = 60 mmHg. There have been some discrepancies of opinions about this recommendation in recent publications. In this study, we retrospectively reviewed 305 severe TBI (STBI) patients with Glasgow Coma Scales (GCS) < or = 8 between January 1, 2002 and March 31, 2003. The study group was stratified according to use or nonuse of intracranial pressure (ICP) monitoring, ICP levels, ages, and GCS levels in order to test the correlation between CCP and the prognosis. The patients < 50-year-old, with higher GCS level, with ICP monitoring, and with ICP levels < 20 mmHg had lower mortality rates and better prognosis (GOS) (p < 0.05 or 0.001). The patients in the GCS 3-5 subgroup had a significantly lower mortality and better prognosis if the CPP value was maintained higher than 70 mmHg (p < 0.05) The optimal CPP maintained < or = 60 mmHg did not fit in all STBI patients. Our study concludes that it is critical to maintain CPP substantially higher in lower GCS level patients.

Effect of hyperbaric oxygen on patients with traumatic brain injury

Hyperbaric oxygen therapy (HBOT) is the medical therapeutic use of oxygen at a higher atmospheric pressure. The United States Food and Drug Administration have approved several clinical applications for HBOT, but HBOT in traumatic brain injury (TBI) patients has still remained in controversial. The purpose of our study is to evaluate the benefit of HBOT on the prognosis of subacute TBI patients. We prospectively enrolled 44 patients with TBI from November 1, 2004 to October 31, 2005. The study group randomly included 22 patients who received HBOT after the patients' condition stabilization, and the other 22 corresponding condition patients were assigned into the matched control group who were not treated with HBOT. The clinical conditions of the patients were evaluated with the Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) before and 3 to 6 months after HBOT. The GCS of the HBOT group was improved from 11.1 to 13.5 in average, and from 10.4 to 11.5 (p < 0.05) for control group. Among those patients with GOS = 4 before the HBOT, significant GOS improvement was observed in the HBOT group 6 months after HBOT. Based on this study, HBOT can provide some benefits for the subacute TBI patients with minimal adverse side effects.

Neurotrauma research in Taiwan

Because of the rapid industrial and economic growth, Taiwan and other developing countries have faced an enormous increase in the number of motorcycles, which has subsequently caused a rapid increase of the motorcycle-related traumatic brain injuries (TBI). In order to tackle this serious problem, stepwise approaches for TBI were implemented in Taiwan from 1991 to 2007. Step 1 was to do a nationwide TBI registry in order to identify the risk factors and determinants. We found that the major cause of TBI in Taiwan was motorcycle-related injury, and very few motorcyclists wore a helmet. Step 2 was to launch the implementation of the helmet use law on June 1, 1997. A rapid decline of TBI hospitalizations and deaths was demonstrated soon thereafter. Step 3 was to enroll into international collaborations with the Global Spine and Head Injury Prevention Project (Global SHIP Project) groups for TBI. The comparative results thus obtained could be used to develop prevention strategies for developing countries. Step 4 was to implement clinical researches for TBI, which included a Propofol study, hyperbaric oxygen therapy (HBOT), brain parenchymal oxygen (PbtO2) monitoring, etc. Step 5 was to develop guidelines for the management of severe TBI in Taiwan. Through a 2-year period of review, discussion, and integration, a 9-chapter guideline was published in June 2007. In summary, our experience and process for management of TBI in Taiwan can be used as a reference for other developing countries.

Molecular cloning and expression analysis of rainbow trout (Oncorhynchus mykiss) CCAAT/enhancer binding protein genes and their responses to induction by GH in vitro and in vivo

CCAAT/enhancer-binding proteins (C/EBPs) are transcription factors consisting of six isoforms and play diverse physiological roles in vertebrates. In rainbow trout (Oncorhynchus mykiss), in addition to the reported C/EBPbeta1, we have isolated cDNA of four other isoforms, C/EBPalpha, C/EBPbeta2, C/EBPdelta1, C/EBPdelta2, from the liver. Comparison of the deduced amino acid sequence of rainbow trout C/EBPs with those of other vertebrates revealed that C/EBP isoforms are highly conserved. The profiles of tissue-specific expression of individual C/EBP isoform mRNA, determined by quantitative real-time (RT)-PCR showed distinct patterns. Furthermore, injection of bovine GH into yearling rainbow trout resulted in a significant increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 but not C/EBPalpha and C/EBPdelta1 in the liver. GH-dependent increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, C/EBPdelta2, and IGF-II were also confirmed by treating rainbow trout hepatoma cells expressing a goldfish GH receptor with bGH. Together with our previous findings, the results presented in this paper strengthen our previous hypothesis that GH may regulate the expression of the IGF-II gene via mediating the expression of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 mRNA.

The delayed genotoxic effect of N-nitroso N-propoxur insecticide in mammalian cells

The N-nitroso derivative of an extensively used insecticide, propoxur, consistently induced dose-responsive chromosome aberrations and sister-chromatid exchanges (SCEs) in Chinese hamster ovary (CHO-W8) cells. Further investigations indicated that post-treatment incubation with a regular 1.5-cell-cycle period did not offer an unbiased estimation of the genotoxicity of N-nitroso carbamate insecticides. The scale of chromosome aberration induction increased with extension of the post-treatment incubation period. Comparable phenomena were not found in CHO-AGT cells proficient for O(6)-methylguanine-DNA-methyltransferase. In CHO-W8 cells, pulsed-treatment of the insecticide in the 1st replication cycle showed higher SCE induction than in the 2nd cycle. Similar phenomenon was also found in SCE induced by N-nitroso derivatives from other carbamate insecticides including aldicarb, carbofuran and methomyl. Treated cells did not show significantly perturbed cell cycle progression until 12 h after treatment removal. Based on the above observations, the O(6)-methylguanine-DNA adduct is suggested to be the major lesion caused by the delayed genotoxic effect of N-methyl carbamate insecticides as described in this report.

RCMAC-based adaptive control for uncertain nonlinear systems

An adaptive control system, using a recurrent cerebellar model articulation controller (RCMAC) and based on a sliding mode technique, is developed for uncertain nonlinear systems. The proposed dynamic structure of RCMAC has superior capability to the conventional static cerebellar model articulation controller in an efficient learning mechanism and dynamic response. Temporal relations are embedded in RCMAC by adding feedback connections in the association memory space so that the RCMAC provides a dynamical structure. The proposed control system consists of an adaptive RCMAC and a compensated controller. The adaptive RCMAC is used to mimic an ideal sliding mode controller, and the compensated controller is designed to compensate for the approximation error between the ideal sliding mode controller and the adaptive RCMAC. The online adaptive laws of the control system are derived based on the Lyapunov stability theorem, so that the stability of the system can be guaranteed. In addition, in order to relax the requirement of the approximation error bound, an estimation law is derived to estimate the error bound. Finally, the simulation and experimental studies demonstrate the effectiveness of the proposed control scheme for the nonlinear systems with unknown dynamic functions.

Associations between VHL genotype and clinical phenotype in familial von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary disorder associated with tumours and cysts in the central nervous system (CNS) and other visceral organs. Germline mutations in the VHL gene on chromosome 3p25-26 are considered the cause of this disease.

MATERIALS AND METHODS

We studied six patients with VHL disease and their relatives. Loss of heterozygosity (LOH) was determined by five flanking microsatellite polymorphic markers in the VHL locus. Multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time polymerase chain reaction (qPCR) amplification were used to detect the genomic deletions. Single-strand conformation polymorphism (SSCP) analysis was applied to test for sequence variations.

RESULTS

Three germline deletions in the VHL gene (142.9, 53.3 and 3.3 kb) were found by MLPA. These deletions were defined clearly by qPCR analyses. The142.9 kb germline deletion was significantly associated with patients with CNS haemangioblastomas (P < 0.01 by Fisher's exact test), and one missense mutation (Gln209Arg) was detected from a patient with a pancreatic cyst in the same family. LOH was also detected from a patient with bilateral renal cell carcinomas.

CONCLUSION

Diverse genetic conditions are associated with the clinical manifestations of VHL disease. Genomic deletions that can be detected by MLPA or qPCR are major causes for this syndrome. Missense mutations and LOH accompanying the disease lead to complex clinical symptoms and genotypic determination can facilitate a clinical diagnosis because of their strong association.

RCMAC Hybrid Control for MIMO Uncertain Nonlinear Systems Using Sliding-Mode Technology

A hybrid control system, integrating principal and compensation controllers, is developed for multiple-input-multiple-output (MIMO) uncertain nonlinear systems. This hybrid control system is based on sliding-mode technique and uses a recurrent cerebellar model articulation controller (RCMAC) as an uncertainty observer. The principal controller containing an RCMAC uncertainty observer is the main controller, and the compensation controller is a compensator for the approximation error of the system uncertainty. In addition, in order to relax the requirement of approximation error bound, an estimation law is derived to estimate the error bound. The Taylor linearization technique is employed to increase the learning ability of RCMAC and the adaptive laws of the control system are derived based on Lyapunov stability theorem and Barbalat's lemma so that the asymptotical stability of the system can be guaranteed. Finally, the proposed design method is applied to control a biped robot. Simulation results demonstrate the effectiveness of the proposed control scheme for the MIMO uncertain nonlinear system.

Robust Fault-Tolerant Control for a Biped Robot Using a Recurrent Cerebellar Model Articulation Controller

A design technique of a recurrent cerebellar model articulation controller (RCMAC)-based fault-tolerant control (FTC) system is investigated to rectify the nonlinear faults of a biped robot. The proposed RCMAC-based FTC (RCFTC) scheme contains two components: 1) an online fault estimation module based on an RCMAC is used to provide approximation information for any nonnominal behavior due to the system failure and modeling error of the biped robot; and 2) a controller module consisting of a computed torque controller and a robust FTC is utilized to achieve FTC. In the controller module, the computed torque controller reveals a basic stabilizing controller to stabilize the system, and the robust FTC is utilized to compensate for the effects of the system failure so as to achieve fault accommodation. The adaptive laws of the RCFTC system are rigorously established based on the Lyapunov function, so that the stability of the system can be guaranteed. Finally, two simulation cases of a biped robot are presented to illustrate the effectiveness of the proposed design method. Simulation results show that the RCFTC system can effectively recover the control performance for the system in the presence of the nonlinear faults and modeling uncertainties.

Molecular signaling in feather morphogenesis

The development and regeneration of feathers have gained much attention recently because of progress in the following areas. First, pattern formation. The exquisite spatial arrangement provides a simple model for decoding the rules of morphogenesis. Second, stem cell biology. In every molting, a few stem cells have to rebuild the entire epithelial organ, providing much to learn on how to regenerate an organ physiologically. Third, evolution and development ('Evo-Devo'). The discovery of feathered dinosaur fossils in China prompted enthusiastic inquiries about the origin and evolution of feathers. Progress has been made in elucidating feather morphogenesis in five successive phases: macro-patterning, micro-patterning, intra-bud morphogenesis, follicle morphogenesis and regenerative cycling.

Wavelet Adaptive Backstepping Control for a Class of Nonlinear Systems

This paper proposes a wavelet adaptive backstepping control (WABC) system for a class of second-order nonlinear systems. The WABC comprises a neural backstepping controller and a robust controller. The neural backstepping controller containing a wavelet neural network (WNN) identifier is the principal controller, and the robust controller is designed to achieve L2 tracking performance with desired attenuation level. Since the WNN uses wavelet functions, its learning capability is superior to the conventional neural network for system identification. Moreover, the adaptation laws of the control system are derived in the sense of Lyapunov function and Barbalat's lemma, thus the system can be guaranteed to be asymptotically stable. The proposed WABC is applied to two nonlinear systems, a chaotic system and a wing-rock motion system to illustrate its effectiveness. Simulation results verify that the proposed WABC can achieve favorable tracking performance by incorporating of WNN identification, adaptive backstepping control, and L2 robust control techniques.

Degradation of di-butyl-phthalate by soil bacteria

Twelve Gram-positive phthalate ester degraders were isolated from soil. Using Biolog GP2 plates, eight of them were identified as belonging to the Corynebacterium-Mycobacterium-Nocardia group, while the remaining four were unidentifiable. When cultured in the presence of di-butyl-phthalate (DBP) in basal salts solution, five of these isolates accomplished more than 90% of DBP degradation within 48 h (fast group), three were placed in the medium group, and the remaining four were placed in the slow group which caused less than 30% of DBP degradation within the same period of time. A 420 bp DNA fragment was amplified from six isolates and none of them fell within the slow group. When compared with the large subunit of phthalate dioxygenase gene (phtA) of Arthrobacter keyseri, 83% and 91% similarities were evident in the nucleotide and amino acid sequences, respectively. However, no correlation between cell surface hydrophobicity and phthalate degradation ability was evident. Six surfactants (Brij 30, Brij 35, Tergitoltype NP-10, Triton N-101, Triton X-100 and SDS) were tested for their abilities to increase degradation rate. When added at the critical micellar concentration (CMC), they all displayed strong growth inhibition against the three bacteria tested, with Brij 30 been the least toxic to isolates G2 and G11, and Brij 35 had the least inhibitory effect for G1. When half the CMC of Brij 30 was incorporated into the basal salts, the inhibitory effect on DBP degradation remained. Soil helped to minimize surfactant toxicity of surfactant and increase the degradation potential of some of the test bacteria. When DBP-amended soil had been aged for three months, decreases in bioavailability were observed but the effect varied tremendously between different organisms. For isolates G1, G2, G5, G7 and G17 the aging effects were almost non-exist. The present study indicates that selection of a suitable degrader may minimize the undesired effect of aging on bioremediation process.

Idiopathic syringomyelia: case report and review of the literature

Syringomyelia is an uncommon disease that is caused most often by type I Chiari malformation, which develops in the hindbrain, and less frequently by other factors which are not limited to the hindbrain, including trauma, infection, or scoliosis. Idiopathic syringomyelia is rare. We present in this article a patient with idiopathic syringomyelia characterized by hypoesthesia and progressive weakness in the left lower limb. Decompression was attempted by means of laminectomy and a syringoarachnoid shunt. Motor, sensory, and bladder functions were monitored by the change in Japanese Orthopedic Association scores, which increased from 10 points preoperatively to 14 points 30 days postoperatively. This case demonstrates the effectiveness of surgical decompression in a patient with remarkable neurological deficit.

Missile Guidance Law Design Using Adaptive Cerebellar Model Articulation Controller

An adaptive cerebellar model articulation controller (CMAC) is proposed for command to line-of-sight (CLOS) missile guidance law design. In this design, the three-dimensional (3-D) CLOS guidance problem is formulated as a tracking problem of a time-varying nonlinear system. The adaptive CMAC control system is comprised of a CMAC and a compensation controller. The CMAC control is used to imitate a feedback linearization control law and the compensation controller is utilized to compensate the difference between the feedback linearization control law and the CMAC control. The online adaptive law is derived based on the Lyapunov stability theorem to learn the weights of receptive-field basis functions in CMAC control. In addition, in order to relax the requirement of approximation error bound, an estimation law is derived to estimate the error bound. Then the adaptive CMAC control system is designed to achieve satisfactory tracking performance. Simulation results for different engagement scenarios illustrate the validity of the proposed adaptive CMAC-based guidance law.

Adaptive Hybrid Control for Linear Piezoelectric Ceramic Motor Drive Using Diagonal Recurrent CMAC Network

This paper presents an adaptive hybrid control system using a diagonal recurrent cerebellar-model-articulation-computer (DRCMAC) network to control a linear piezoelectric ceramic motor (LPCM) driven by a two-inductance two-capacitance (LLCC) resonant inverter. Since the dynamic characteristics and motor parameters of the LPCM are highly nonlinear and time varying, an adaptive hybrid control system is therefore designed based on a hypothetical dynamic model to achieve high-precision position control. The architecture of DRCMAC network is a modified model of a cerebellar-model-articulation-computer (CMAC) network to attain a small number of receptive-fields. The novel idea of this study is that it employs the concept of diagonal recurrent neural network (DRNN) in order to capture the system dynamics and convert the static CMAC into a dynamic one. This adaptive hybrid control system is composed of two parts. One is a DRCMAC network controller that is used to mimic a conventional computed torque control law due to unknown system dynamics, and the other is a compensated controller with bound estimation algorithm that is utilized to recover the residual approximation error for guaranteeing the stable characteristic. The effectiveness of the proposed driving circuit and control system is verified with hardware experiments under the occurrence of uncertainties. In addition, the advantages of the proposed control scheme are indicated in comparison with a traditional integral-proportional (IP) position control system.

Distinct Wnt members regulate the hierarchical morphogenesis of skin regions (spinal tract) and individual feathers

Skin morphogenesis occurs in successive stages. First, the skin forms distinct regions (macropatterning). Then skin appendages with particular shapes and sizes form within each region (micropatterning). Ectopic DKK expression inhibited dermis formation in feather tracts and individual buds, implying the importance of Wnts, and prompted the assessment of individual Wnt functions at different morphogenetic levels using the feather model. Wnt 1, 3a, 5a and 11 initially were expressed moderately throughout the feather tract then were up-regulated in restricted regions following two modes: Wnt 1 and 3a became restricted to the placodal epithelium, then to the elongated distal bud epidermis; Wnt 5a and 11 intensified in the inter-tract region and interprimordia epidermis or dermis, respectively, then appeared in the elongated distal bud dermis. Their role in feather tract formation was determined using RCAS mediated misexpression in ovo at E2/E3. Their function in periodic feather patterning was examined by misexpression in vitro using reconstituted E7 skin explant cultures. Wnt 1 reduced spinal tract size, but enhanced feather primordia size. Wnt 3a increased dermal thickness, expanded the spinal tract size, reduced interbud domain spacing, and produced non-tapering "giant buds". Wnt 11 and dominant negative Wnt 1 enhanced interbud spacing, and generated thinner buds. In cultured dermal fibroblasts, Wnt 1 and 3a stimulated cell proliferation and activated the canonical beta-catenin pathway. Wnt 11 inhibited proliferation but stimulated migration. Wnt 5a and 11 triggered the JNK pathway. Thus distinctive Wnts have positive and negative roles in forming the dermis, tracts, interbud spacing and the growth and shaping of individual buds.

A prospective study of nocturia and the quality of life of elderly patients with obstructive sleep apnea or sleep onset insomnia

OBJECTIVE

To prospectively evaluate the relationship between obstructive sleep apnea syndrome (OSAS), nocturia and quality of life in elderly patients free of the urologic and medical conditions that lead to increased nocturia.

METHODS

Prospective study of nocturia in men 65 years and older with isolated OSAS or sleep onset insomnia. After a 7-day nocturia evaluation and nocturnal polysomnography, Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI), Quality of Life (SF-36) were administered.

RESULTS

OSAS patients with frequent nocturia had significantly greater body mass index (BMI), greater apnea-hypopnea index (AHI), lower lowest oxygen saturation and lower SF-36 subscale scores. Treatment with nasal continuous positive airway pressure (CPAP) for OSAS and behavioral techniques for insomnia improved ESS and BDI scores for all three groups. SF-36 subscale scores improved more in subjects with multiple nocturia. AHI and BMI explain 38% of the variance for nocturia.

CONCLUSION

Nasal CPAP reduces OSA and nocturia and improves quality of life of elderly patients.

Adaptive CMAC-based supervisory control for uncertain nonlinear systems

An adaptive cerebellar-model-articulation-controller (CMAC)-based supervisory control system is developed for uncertain nonlinear systems. This adaptive CMAC-based supervisory control system consists of an adaptive CMAC and a supervisory controller. In the adaptive CMAC, a CMAC is used to mimic an ideal control law and a compensated controller is designed to recover the residual of the approximation error. The supervisory controller is appended to the adaptive CMAC to force the system states within a predefined constraint set. In this design, if the adaptive CMAC can maintain the system states within the constraint set, the supervisory controller will be idle. Otherwise, the supervisory controller starts working to pull the states back to the constraint set. In addition, the adaptive laws of the control system are derived in the sense of Lyapunov function, so that the stability of the system can be guaranteed. Furthermore, to relax the requirement of approximation error bound, an estimation law is derived to estimate the error bound. Finally, the proposed control system is applied to control a robotic manipulator, a chaotic circuit and a linear piezoelectric ceramic motor (LPCM). Simulation and experimental results demonstrate the effectiveness of the proposed control scheme for uncertain nonlinear systems.

Morphogenesis of chicken liver: identification of localized growth zones and the role of beta-catenin/Wnt in size regulation

During development and regeneration, new cells are added and incorporated to the liver parenchyma. Regulation of this process contributes to the final size and shape of the particular organs, including the liver. We identified the distribution of liver growth zones using an embryonic chicken model because of its accessibility to experimentation. Hepatocyte precursors were first generated all over the primordia surrounding the vitelline blood vessel at embryonic day 2 (E2), then became limited to the peripheral growth zones around E6. Differentiating daughter cells of the peripheral hepatocyte precursors were shown by DiI microinjection to be laid inward and were subsequently organized to form the hepatic architecture. At E8, hepatocyte precursor cells were further restricted to limited segments of the periphery, called localized growth zones (LoGZ). Adhesion and signaling molecules in the growth zone were studied. Among them, beta-catenin and Wnt 3a were highly enriched. We overexpressed constitutively active beta-catenin using replication competent avian sarcoma (RCAS) virus. Liver size increased about 3-fold with an expanded hepatocyte precursor cell population. In addition, blocking beta-catenin activity by either overexpression of dominant-negative LEF1 or overexpression of a secreted Wnt inhibitor Dickkopf (DKK) resulted in decreased liver size with altered liver shape. Our data suggest that (1) the duration of active growth zone activity modulates the size of the liver; (2) a shift in the position of the localized growth zone helps to shape the liver; and (3) beta-catenin/Wnt are involved in regulating growth zone activities during liver development.

Integument pattern formation involves genetic and epigenetic controls: feather arrays simulated by digital hormone models

Pattern formation is a fundamental morphogenetic process. Models based on genetic and epigenetic control have been proposed but remain controversial. Here we use feather morphogenesis for further evaluation. Adhesion molecules and/or signaling molecules were first expressed homogenously in feather tracts (restrictive mode, appear earlier) or directly in bud or inter-bud regions ( de novo mode, appear later). They either activate or inhibit bud formation, but paradoxically colocalize in the bud. Using feather bud reconstitution, we showed that completely dissociated cells can reform periodic patterns without reference to previous positional codes. The patterning process has the characteristics of being self-organizing, dynamic and plastic. The final pattern is an equilibrium state reached by competition, and the number and size of buds can be altered based on cell number and activator/inhibitor ratio, respectively. We developed a Digital Hormone Model which consists of (1) competent cells without identity that move randomly in a space, (2) extracellular signaling hormones which diffuse by a reaction-diffusion mechanism and activate or inhibit cell adhesion, and (3) cells which respond with topological stochastic actions manifested as changes in cell adhesion. Based on probability, the results are cell clusters arranged in dots or stripes. Thus genetic control provides combinational molecular information which defines the properties of the cells but not the final pattern. Epigenetic control governs interactions among cells and their environment based on physical-chemical rules (such as those described in the Digital Hormone Model). Complex integument patterning is the sum of these two components of control and that is why integument patterns are usually similar but non-identical. These principles may be shared by other pattern formation processes such as barb ridge formation, fingerprints, pigmentation patterning, etc. The Digital Hormone Model can also be applied to swarming robot navigation, reaching intelligent automata and representing a self-re-configurable type of control rather than a follow-the-instruction type of control.

Consumer acceptance of fresh-cut iceberg lettuce treated with 2% hydrogen peroxide and mild heat

An antibacterial treatment consisting of 2% hydrogen peroxide at 50 degrees C for 60 s was evaluated for its effects on the sensory quality of fresh-cut iceberg lettuce. Treated lettuce was packaged in polyethylene film by a protocol used in the fresh-cut produce industry and then stored along with untreated controls for 3, 10, and 15 days at 5 degrees C. Gas chromatographic analysis confirmed that the desired initial volume (approximately 6 liters) and oxygen gas content (approximately 10%) were maintained during storage. Consumers from the local community who were the primary shoppers for their households and who purchased and ate lettuce regularly evaluated the appearance, color, aroma, flavor, and texture of the lettuce and their overall liking of the lettuce. Forty consumers were recruited to evaluate processing replication 1 on 26 April, and another 40 were chosen to evaluate processing replication 2 on 3 May. Because replication differences were observed in instrumental color measurements and in mean sensory ratings, replications were not pooled for the two test dates. Lettuce purchased for processing replication 2 was considerably greener than that used in replication 1. Overall, the antibacterial treatment was more effective than the control treatment in maintaining sensory quality over 15 days of storage, provided that the lettuce was initially intensely green. Three-fourths of the participants indicated that they would be willing to buy precut packaged lettuce that had already been treated at the packinghouse or processing plant with an antibacterial solution, and of these participants, 62.5% indicated that they would be willing to pay 5 to 10 cents more per bag.

Dehydroepiandrosterone sulfate (DHEAS) suppresses P2X purinoceptor-coupled responses in PC12 cells

Some steroids rapidly alter neuronal excitability through interaction with neurotransmitter-gated ion channels in addition to their well-known genomic effects via intracellular steroid receptors. Such effects were found in GABA receptor, nicotinic receptors, yet not investigated in P2X purinoceptors. In this study, the effects of dehydroepiandrosterone sulfate on the P2 purinoceptor was investigated. Results show that dehydroepiandrosterone sulfate acutely inhibits P2X purinoceptor functions in PC12 cells. Dehydroepiandrosterone sulfate suppressed ATP-induced cytosolic free calcium concentration ([Ca(2+)](i)) rise, cytosolic free sodium concentration ([Na(+)](i)) rise, and dopamine secretion in the presence of external calcium, but had no effect on ATP-induced [Ca(2+)](i) rise in the absence of external calcium or on UTP-induced [Ca(2+)](i) rise in the absence or presence of external calcium. Our data show that dehydroepiandrosterone sulfate exerted its effect on P2X, but not on the P2Y purinoceptors found in PC12 cells. Estradiol and estrone have similar effects on P2X purinoceptor, but dehydroepiandrosterone and progesterone do not.

Inadvertent hypothermia causes pulseless electrical activity in a patient during cervical spine surgery--a case report

Recent studies have shown that hypothermia triples the incidence of major cardiac events. We present a happening in which a 71-year-old patient developed pulseless electrical activity (PEA) while he was undergoing cervical laminectomy for spinal stenosis in the sitting position. Thromboembolism or venous air embolism and acute myocardial infarction were respectively excluded by transesophageal echocardiography and cardiac enzymes analysis to be the causes of the cardiac event. The abnormal finding that stood out was low nasopharyngeal temperature (31 degrees C) during the procedure, which was thought to contribute to the development of the PEA episode.

Glutamine metabolism in sepsis and infection

Severe infection causes marked derangements in the flow of glutamine among organs, and these changes are accompanied by significant alterations in regional cell membrane transport and intracellular glutamine metabolism. Skeletal muscle, the major repository of glutamine, exhibits a twofold increase in glutamine release during infection, which is associated with a significant increase in endogenous glutamine biosynthesis. Despite an increase in glutamine synthetase activity in skeletal muscle, the intracellular glutamine pool becomes depleted, indicating that release rates exceed rates of synthesis. Simultaneously, the circulating pool of glutamine does not increase, indicating accelerated uptake by other organs. The liver appears to be the major organ of glutamine uptake in severe infection; studies in endotoxemic rodents have shown net hepatic glutamine uptake to increase by as much as 8- to 10-fold. This increase is due partially to increases in liver blood flow, but also to a three- to fourfold increase in hepatocyte System N activity in the liver. Cytokines and glucocorticoids mediate the increased uptake of glutamine by the liver in septic states as well as other compounds. Sepsis does not appear to induce an increase in System N gene expression, indicating that the increase in hepatic glutamine transport observed during severe infection is probably regulated at the protein level. The bowel displays a decrease in glutamine utilization during sepsis, a response that may be related to the decrease in circulating insulin-like growth factor-1 (IGF-1) levels that is characteristic of sepsis. Recent studies suggest that IGF-1 has a direct effect on stimulating glutamine transport across the gut lumen and thus may represent a therapeutic avenue for improving gut nutrition during severe infection. The cells of the immune system (lymphocytes, macrophages) are also major glutamine consumers during inflammatory states in which cell proliferation is increased. Under these conditions, glutamine availability can become rate limiting for key cell functions, such as phagocytosis and antibody production.

Destruction of Escherichia coli O157:H7 and Salmonella enteritidis in cow manure composting

Application of cow manure and composted manure in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Salmonella Enteritidis and Escherichia coli O157:H7. In this study, rifampicin-resistant (RifR) E. coli O157:H7 and Salmonella Enteritidis at a level of 7 log CFU/g of raw compost feed were used to determine the effect of a bench-scale composting system on their survival. RifR E. coli O157:H7 was not detected after 72 h of composting at 45 degrees C, and RifR Salmonella Enteritidis was not detected after 48 h. The use of selective media for enrichment failed to recover in the composting samples held at 45 degrees C for 96 h. However, the pathogens showed no change in bacterial numbers when the composting system was held at room temperature. Thus, properly composted manure can be safely used in food crop production while minimizing the likelihood of microbial contamination.

Combined conventional and jet ventilation in airway management in tracheal tumor

Tumors on the carina are uncommon, and their anesthetic management can present a considerable challenge. The principle anesthetic consideration is ventilation and oxygenation in the face of an open airway. A 60-year-old man patient suffered a carinal tumor, which occupied 70% of the both main bronchi and bled spontaneously while coughing. Surgical resection and reconstruction were done. The carinal surgical approach was a right posterolateral thoracotomy, and the patient was placed in the left decubitus position. Because we could not insert the jet catheter past the mass, high frequency jet ventilation to ventilate the dependent lung could not be applied. Our choice was differential lung ventilation with a combination of conventional and high frequency jet ventilation modes to preserve oxygenation during tumor excision and tracheal reconstruction. An episode of desaturation was successfully treated during removal of tumor. The postoperative course was uneventful. The patient was sent to the intensive care unit after surgery and discharged on the 11th day. He received further combined chemotherapy and radiotherapy during his next admission. Fiberoptic examination on the 5 months later no evidence of recurrence. In summary, we described our airway management on carinal tumor excision, especially the tumor was so large that dependent lung jet ventilation could not employ.

Hemodynamic responses of thiopental and propofol in different-aged patients during endotracheal intubation

BACKGROUND

Thiopental and propofol are 2 popularly used anesthetic induction agents that have different pharmacological and pharmacokinetic actions. It is not clear how the hemodynamic responses differ in different-aged patients using these 2 drugs for anesthetic induction. The aim of this study was to investigate the hemodynamic responses to propofol and thiopental of different-aged patients during endotracheal intubation.

METHODS

Sixty patients, 20 to 83 years old, were included in this study. Patients were randomly divided into 6 groups according to age and different inductive anesthetics. Non-invasive blood pressure (NIBP) monitoring was performed every minute before anesthesia, during anesthetic induction with 5 mg.kg-1 thiopental or 2 mg.kg-1 propofol intravenously, and after intubation.

RESULTS

Propofol induction produced a smaller mean arterial pressure increase immediately after intubation than did thiopental induction in adult and elderly groups (101.0 +/- 18.5 and 104.0 +/- 21.1 mmHg in the propofol groups vs. 138.3 +/- 17.1 and 138.9 +/- 16.1 mmHg in the thiopental groups at 1 minute after intubation, p < 0.001 and p = 0.001, respectively). Differences in heart rate between propofol and thiopental groups were found in young and adult groups (85.1 +/- 9.2 and 81.7 +/- 10.9 in the propofol groups vs. 94.5 +/- 9.9 and 95.0 +/- 14.0 beats per minute in the thiopental groups at 1 minute after intubation, p = 0.041 and p = 0.029, respectively).

CONCLUSION

Propofol induction produced more stable hemodynamics after intubation in adult and elderly patients than did thiopental induction. Therefore, it is safer to use propofol for induction and intubation in adult and elderly patients.

Pneumopericardium after bronchoscopic carbon dioxide laser surgery--a case report

A female baby sustained pneumopericardium after bronchoscopic CO2 laser surgery for tracheal stenosis. Perioperative pneumopericardium though rare is a life-threatening condition in babies. The symptoms are usually not specific such as hypotension, bradycardia, muffled heart sound, cardiovascular collapse, etc. The causes and clinical findings of pneumopericardium were reviewed, as are the radiographic features so as to differentiate the condition from pneumomediastinum. Early recognition of pneumopericardium is important, because emergent pericardiocentesis may be required if there is clinical evidence of cardiac tamponade.

Anterior mediastinal tumour identified by intraoperative transesophageal echocardiography

PURPOSE

To report a child with anterior mediastinal tumour misdiagnosed as pericardial effusion who had been sent to the operating theatre for drainage. After induction of general anesthesia she developed cardio-respiratory collapse. The diagnosis was made with the aid of transesophageal echocardiography (TEE).

CLINICAL FEATURES

A 14-yr-old girl suffered from cough and intermittent fever for one month before admission. Four days before admission, she became orthopneic and was admitted to the intensive care unit. Precordial echocardiography showed an anterior and posterior echolucent space between the pericardium and epicardium that was thought to be a pericardial effusion. She was sent to the operating room for emergency drainage. After induction of general anesthesia, breath sounds were not heard on the left side of the chest. The patient developed increasing hypoxemia and hypotension despite cardiocentesis. A TEE determined that an anterior mediastinal mass was the cause of her hypoxemia and hypotension. The tumour was debulked and the patient made an uneventful postoperative recovery.

CONCLUSION

In this case, the correct diagnosis of an anterior mediastinal mass was made with TEE. The place of TEE may be indicated in patients with unexplained hypoxemia and hypotension.

Interleukin-10-induced T cell unresponsiveness can be reversed by dendritic cell stimulation

The secretion of immunosuppressive factors like interleukin-10 (IL-10), either by tumor cells or by tumor-infiltrating leukocytes, has been recognized as one of the mechanisms involved in tumor immunological escape and a serious obstacle for successful immunotherapy. Therefore, any therapeutic attempts aimed at inducing antitumor immunity in tumor-bearing hosts must overcome this immunosuppressive state. This study aimed to determine whether dendritic cell (DC) immunization, a promising approach to induce antitumor immunity, could break IL-10-induced anergic state in CD4+ T cells, essential cells in generating tumor-specific immunity. We found that the ability of DC to reverse IL-10-induced anergic state in human CD4+ T cells is dependent on the IL-10 concentration that T cells have been exposed to and the degree of DC maturation. The efficacy of mature DC in reversing T cell anergy can be mimicked by higher cell numbers of immature DC. In addition, activated T cells induced by DC stimulation are sensitive to IL-10 treatment. Collectively, our results suggest the use of mature DC and the necessity of antagonizing the action of tumor-derived IL-10 in immunotherapy of cancer with DC immunization.

T cell receptor binding kinetics and special role of Valpha in T cell development and activation

The kinetics of the interaction between T cell receptor (TCR) and major histocompatibility complex (MHC) has an important role in determining thymocyte-positive and -negative selection in the thymus, as well as in T cell activation. The alpha chain of the TCR is the major player in determining how the TCR fits onto the MHC ligand, and thus has a major role in determining whether a T cell develops as class I or class II restricted. In this article, we summarize recent data from our laboratory and others on the role of polymorphism in the Valpha combining site in determining MHC class restriction, and on kinetic parameters in thymocyte selection.