Allergy in Hong Kong: an unmet need in service provision and training

Many children in Hong Kong have allergic diseases and epidemiological data support a rising trend. Only a minority of children will grow out of their allergic diseases, so the heavy clinical burden will persist into adulthood. In an otherwise high-quality health care landscape in Hong Kong, allergy services and training are a seriously unmet need. There is one allergy specialist for 1.5 million people, which is low not only compared with international figures, but also compared with most other specialties in Hong Kong. The ratio of paediatric and adult allergists per person is around 1:460 000 and 1:2.8 million, respectively, so there is a severe lack of adult allergists, while the paediatric allergists only spend a fraction of their time working with allergy. There are no allergists and no dedicated allergy services in adult medicine in public hospitals. Laboratory support for allergy and immunology is not comprehensive and there is only one laboratory in the public sector supervised by accredited immunologists. These findings clearly have profound implications for the profession and the community of Hong Kong and should be remedied without delay. Key recommendations are proposed that could help bridge the gaps, including the creation of two new pilot allergy centres in a hub-and-spoke model in the public sector. This could require recruitment of specialists from overseas to develop the process if there are no accredited allergy specialists in Hong Kong who could fulfil this role.

Relative adrenal insufficiency in chronic liver disease: its prevalence and effects on long-term mortality

BACKGROUND

The relationship between relative adrenal insufficiency (RAI) and chronic liver disease is unclear.

AIM

To determine the frequency with which RAI is observed in noncritically ill patients at various stages of chronic liver disease, and the correlation between RAI and disease severity and long-term mortality.

METHODS

In total, 71 non-critically ill patients with liver cirrhosis (n = 54) and chronic hepatitis (n = 17) were evaluated prospectively. A short stimulation test (SST) with 250 μg of corticotrophin was performed to detect RAI. RAI was defined as an increase in serum cortisol of <9 μg/dL in patients with a basal total cortisol of <35 μg/dL.

RESULTS

RAI was observed in only 13 (24.1%) of 54 patients with cirrhosis. Compared to those without RAI, cirrhotic patients with RAI had significantly higher Child-Turcotte-Pugh score (10.3 ± 1.7 vs. 7.1 ± 1.8, mean ± s.d., P < 0.001) and Model for End-Stage Liver Disease score (14.5 ± 6.6 vs. 9.4 ± 3.7, P = 0.017). The cortisol response to corticotropin was negatively correlated with the severity of cirrhosis (P < 0.05). In addition, the mortality rate was higher in cirrhotic patients with RAI (69.2%) than in those without RAI (4.9%; P < 0.001) during the follow-up period of 20.1 ± 13.5 months (range, 5.8-51.1 months). The cumulative 1-year survival rates in cirrhotic patients with and without RAI were 69.2% and 95.0%, respectively (P = 0.05), while the corresponding cumulative 3-year survival rates were 0% and 95.0% (P < 0.001).

CONCLUSIONS

Relative adrenal insufficiency is more commonly observed in those with severe cirrhosis, and is clearly associated with more advanced liver disease and a shortened long-term survival. This suggests that relative adrenal insufficiency is an independent prognostic factor in non-critically ill patients with cirrhosis.

A new histone deacetylase inhibitor improves liver fibrosis in BDL rats through suppression of hepatic stellate cells

Background and Purpose

Activation of hepatic stellate cells (HSCs) is a crucial step in the pathogenesis of hepatic fibrosis. Histone deacetylase (HDAC) is an attractive target in liver fibrosis because it plays a key role in gene expression and cell differentiation. We have developed a HDAC inhibitor, N-hydroxy-7-(2-naphthylthio)heptanomide (HNHA), and investigated the anti-fibrotic activity of HNHA in vitro and in vivo.

Experimental Approach

We investigated the anti-fibrotic effect of HNHA on mouse and human HSC activation in vitro and in the liver of bile duct-ligated (BDL) rats in vivo using cell proliferation assays, cell cycle analysis, biochemical assay, immunohistochemistry and Western blots. Liver pathology was assessed with histochemical techniques.

Key Results

HNHA inhibited proliferation and arrested the cell cycle via p21 induction in HSCs. In addition, HNHA induced apoptosis of HSCs, which was correlated with reduced COX-2 expression, NF-κB activation and cell death signals. HNHA restored liver function and decreased the accumulation of extracellular matrix in the liver via suppression of HSC activation in BDL rats in vivo. HNHA administration also increased survival in BDL rats.

Conclusions and Implications

HNHA improved liver function, suppressed liver fibrosis and increased survival of BDL rats, accompanied by reduction of cell growth, activation and survival of HSCs. These findings show that HNHA may be a potent anti-fibrosis agent against hepatic fibrosis because of its multi-targeted inhibition of HSC activity in vivo and in vitro.

Immunotherapy for peanut allergy

Peanut allergy is one of the commonest food hypersensitivities causing fatal or near-fatal reactions. There is, currently, no preventive treatment and the incidence of severe allergic reactions during peanut desensitisation has limited its clinical use. Anti-immunoglobulin E therapy has been shown to be effective in preventing peanut-induced reactions but it does not result in long-term tolerance. Two important advances have recently been reported. One involves gradual oral introduction of peanut protein to desensitise, whereas the other approach uses a combination of anti-immunoglobulin E and oral peanut immunotherapy. Both approaches could offer a way to desensitise with a far greater margin of safety than has, hitherto, been reported. This article provides an overview of the literature on peanut immunotherapy and describes the experience in a small group of children in Hong Kong who were treated successfully using anti-immunoglobulin E combined with oral peanut desensitisation.

A wireless power transmission system for implantable devices in freely moving rodents

Reliable wireless power delivery for implantable devices in animals is highly desired for safe and effective experimental use. Batteries require frequent replacement; wired connections are inconvenient and unsafe, and short-distance inductive coupling requires the attachment of an exterior transmitter to the animal's body. In this article, we propose a solution by which animals with implantable devices can move freely without attachments. Power is transmitted using coils attached to the animal's cage and is received by a receiver coil implanted in the animal. For a three-dimensionally uniform delivery of power, we designed a columnar dual-transmitter coil configuration. A resonator-based inductive link was adopted for efficient long-range power delivery, and we used a novel biocompatible liquid crystal polymer substrate as the implantable receiver device. Using this wireless power delivery system, we obtain an average power transfer efficiency of 15.2% (minimum efficiency of 10% and a standard deviation of 2.6) within a cage of 15×20×15 cm3.

Technical tips and issues of biliary stenting, focusing on malignant hilar obstruction

In patients with inoperable hilar cholangiocarcinoma (HCCA), palliative endoscopic or percutaneous drainage provides benefits in terms of symptomatic improvement and quality of life. Endoscopic biliary stent placement is considered the gold standard, with metal stents preferred over plastic stents in patients with more than three months of life expectancy. However, the endoscopic management of advanced hilar obstruction is often more challenging and complex than distal malignant biliary obstructions. Recently, the Asia-Pacific working group on hepatobiliary cancers produced consensus recommendations on the use of endoscopic vs. percutaneous drainage and unilateral vs. bilateral drainage in the management of HCCA. However, these guidelines must be weighed against context-specific information, such as the volume of liver drainage required, life expectancy of the patient, and the available expertise. In this literature review, we describe the issues commonly encountered during endoscopic biliary stenting for malignant hilar obstruction and provide technical guidance to improve success rates and patient outcomes.

Death-associated protein kinase 1 has a critical role in aberrant tau protein regulation and function

The presence of tangles composed of phosphorylated tau is one of the neuropathological hallmarks of Alzheimer's disease (AD). Tau, a microtubule (MT)-associated protein, accumulates in AD potentially as a result of posttranslational modifications, such as hyperphosphorylation and conformational changes. However, it has not been fully understood how tau accumulation and phosphorylation are deregulated. In the present study, we identified a novel role of death-associated protein kinase 1 (DAPK1) in the regulation of the tau protein. We found that hippocampal DAPK1 expression is markedly increased in the brains of AD patients compared with age-matched normal subjects. DAPK1 overexpression increased tau protein stability and phosphorylation at multiple AD-related sites. In contrast, inhibition of DAPK1 by overexpression of a DAPK1 kinase-deficient mutant or by genetic knockout significantly decreased tau protein stability and abolished its phosphorylation in cell cultures and in mice. Mechanistically, DAPK1-enhanced tau protein stability was mediated by Ser71 phosphorylation of Pin1, a prolyl isomerase known to regulate tau protein stability, phosphorylation, and tau-related pathologies. In addition, inhibition of DAPK1 kinase activity significantly increased the assembly of MTs and accelerated nerve growth factor-mediated neurite outgrowth. Given that DAPK1 has been genetically linked to late onset AD, these results suggest that DAPK1 is a novel regulator of tau protein abundance, and that DAPK1 upregulation might contribute to tau-related pathologies in AD. Therefore, we offer that DAPK1 might be a novel therapeutic target for treating human AD and other tau-related pathologies.

Staging accuracy of endoscopic ultrasound performed by nonexpert endosonographers in patients with resectable esophageal squamous cell carcinoma: is it possible?

The accuracy of endoscopic ultrasound (EUS) is operator-dependent. According to learning curve study, the accuracy of EUS T-staging for esophageal cancer has been reported to be greater in an investigator who had performed at least 100 EUS examinations. We determined comparative study regarding T-staging accuracy of EUS for esophageal squamous cell carcinoma between expert and nonexpert endoscopic ultrasonographers. We retrospectively identified 73 consecutive patients with esophageal squamous cell carcinoma who underwent EUS and endoscopic mucosal resection, endoscopic submucosal dissection, or surgery. EUS was performed by expert (Group 1) and nonexpert (Group 2) endoscopic ultrasonographers in multitertiary hospitals. Groups 1 and 2 were 37 and 36 patients during 2005-2011, respectively. Forty-two patients (57.5%) of the overall patients underwent surgical exploration. Correct endoscopic ultrasonographic T-staging of Group 1 was observed in 34 (91.9%) patients, while that of Group 2 was observed in 26 (72.2%) patients. And there was significant difference in correct endoscopic ultrasonographic T-staging between Group 1 and Group 2 (P = 0.035). The incorrect endoscopic ultrasonographic T-staging of Group 1 were three cases that were overstaging (8.1%), but in Group 2 there were seven overstaging (19.4%) and three understaging (8.3%). There was no significant difference in overstaging or understaging of incorrect endoscopic ultrasonographic T-staging between Group 1 and Group 2 (P = 0.528). This study first provides evidence that endoscopic ultrasonographic T-staging of nonexpert endoscopic ultrasonographers was inferior to be correct, compared with that of expert endoscopic ultrasonographers. EUS staging for esophageal cancer should be performed by expert endoscopic ultrasonographers to provide appropriate management strategy.

High-resolution impedance manometry facilitates assessment of pharyngeal residue and oropharyngeal dysphagic mechanisms

The utility of high-resolution impedance manometry (HRIM) for evaluating oropharyngeal dysphagia (OPD) has been investigated. These approaches are limited because of the sophisticated methodology. A method of transforming HRIM into a simple and useful diagnostic tool for evaluating OPD is needed. A videofluoroscopic swallowing study (VFSS) and HRIM were performed by independent blinded examiners in 26 consecutive healthy volunteers (12 men; median age, 56.5 years) and 10 OPD patients (five men; median age, 59.5 years). Upper esophageal sphincter (UES) relaxation parameters were measured using a standard HRIM protocol. Peristalsis and bolus transit of the pharyngoesophageal (PE) segment were assessed using an HRIM-modified protocol in which the catheter was pulled back 10 cm. PE bolus transits were evaluated with an impedance contour pattern (linear vs. stasis) method. A significant difference was observed between the manometric measures of healthy volunteers and OPD patients for only the duration of pharyngeal contraction (0.49 ± 0.19 vs. 0.76 ± 0.33 s, P = 0.04). The percentage agreement and kappa value for detecting pharyngeal residue between the VFSS and the impedance analysis were 100% and 1.00, respectively. HRIM allowed for comprehensive assessment of abnormal pharyngeal components that caused pharyngeal residue on VFSS in two patients; reduced base of the tongue versus weak pharyngeal contraction in one, and reduced relaxation of the UES versus reduced laryngeal elevation in the remaining patient. Our findings demonstrated that HRIM using a simple methodology (i.e., pull-back of the catheter) detected pharyngeal residue through a simple analysis of the impedance contour pattern (linear vs. stasis). Furthermore, HRIM facilitated a comprehensive assessment of OPD mechanisms and recognition of subtle abnormalities not yet visible to the naked eye on VFSS.

Pelvic congestion syndrome diagnosed using endoscopic ultrasonography

Pelvic congestion syndrome (PCS) presents with a non-cyclic pelvic pain lasting more than six months in duration in premenopausal women. Pelvic ultrasonography or computed tomography is usually the first imaging modality used to evaluate patients with suspected PCS. PCS is confirmed by visible congestion of the pelvic veins on selective ovarian venography. To our knowledge, the role of endoscopic ultrasonography (EUS) has not been reported. EUS showed multiple dilated structures especially on left side around the uterus and ovaries, which are compatible with other radiological investigations of PCS Although PCS is not typical areas within the scope of practice of endosonographers, it is useful to be familiar with the findings. We report a case of PCS that was diagnosed with the aid of EUS.

A carcinoid tumour arising within a tailgut cyst: a diagnostic challenge

A 49-year-old man was referred with constipation that had lasted for a few months. On colonoscopy, a subepithelial tumour more than 4 cm in size was seen in the rectum. He underwent endoscopic ultrasound and pelvic magnetic resonance imaging. He was preoperatively diagnosed with a rectal duplication cyst based on imaging studies. However, the final histopathologic diagnosis after transanal excision of the rectal mass was rectal carcinoid tumour with tailgut cyst. Tailgut cysts are very rare congenital lesions in the presacral area and are most often discovered incidentally in middle-aged women. It is difficult to distinguish the imaging appearance of tailgut cysts from that of many other retrorectal cysts. Malignant transformation of tailgut cysts has been estimated to occur in 2 to 13% of cases. We report the diagnostic difficulties encountered in a case of carcinoid tumour arising from a tailgut cyst in a male patient.

Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures

BACKGROUND AND STUDY AIMS

Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision.

PATIENTS AND METHODS

A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy.

RESULTS

The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents.

CONCLUSIONS

Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded.

An ultra-low power (ULP) bandage-type ECG sensor for efficient cardiac disease management

This paper proposed an ultra-low power bandage-type ECG sensor (the size: 76 × 34 × 3 (mm(3)) and the power consumption: 1 mW) which allows for a continuous and real-time monitoring of a user's ECG signals over 24h during daily activities. For its compact size and lower power consumption, we designed the analog front-end, the SRP (Samsung Reconfigurable Processor) based DSP of 30 uW/MHz, and the ULP wireless RF of 1 nJ/bit. Also, to tackle motion artifacts(MA), a MA monitoring technique based on the HCP (Half-cell Potential) is proposed which resulted in the high correlation between the MA and the HCP, the correlation coefficient of 0.75 ± 0.18. To assess its feasibility and validity as a wearable health monitor, we performed the comparison of two ECG signals recorded form it and a conventional Holter device. As a result, the performance of the former is a little lower as compared with the latter, although showing no statistical significant difference (the quality of the signal: 94.3% vs 99.4%; the accuracy of arrhythmia detection: 93.7% vs 98.7%). With those results, it has been confirmed that it can be used as a wearable health monitor due to its comfortability, its long operation lifetime and the good quality of the measured ECG signal.

Columnar transmitter based wireless power delivery system for implantable device in freely moving animals

A wireless power delivery system is developed to deliver electrical power to the neuroprosthetic devices that are implanted into animals freely moving inside the cage. The wireless powering cage is designed for long-term animal experiments without cumbersome wires for power supply or the replacement of batteries. In the present study, we propose a novel wireless power transmission system using resonator-based inductive links to increase power efficiency and to minimize the efficiency variations. A columnar transmitter coil is proposed to provide lateral uniformity of power efficiency. Using this columnar transmitter coil, only 7.2% efficiency fluctuation occurs from the maximum transmission efficiency of 25.9%. A flexible polymer-based planar type receiver coil is fabricated and assembled with a neural stimulator and an electrode. Using the designed columnar transmitter coil, the implantable device successfully operates while it moves freely inside the cage.

Interleukin-25 promotes basic fibroblast growth factor expression by human endothelial cells through interaction with IL-17RB, but not IL-17RA

BACKGROUND

Unlike other IL-17 family members, the Th2-derived cytokine IL-25 (IL-17E) induces (promotes) Th2 responses. One or both of the two receptors for IL-25 (IL-17RA, IL-17RB) is expressed on inflammatory cells and tissue structural cells, suggesting that in addition to promoting Th2-type inflammation IL-25 may also act on structural cells at sites of Th2-type inflammation such as in the asthmatic bronchial mucosa to promote remodelling changes.

OBJECTIVE

Our previous studies showed elevated expression of IL-25 and IL-17RB immunoreactivity in asthmatic airways with co-localization of the latter to endothelial cells. We therefore hypothesized that IL-25 acts on endothelial cells through this receptor to induce production of the key angiogenic and remodelling cytokine basic fibroblast growth factor (bFGF).

METHODS

Polymerase chain reaction (PCR) immunocytochemistry/immunohistochemistry and ELISA were employed to detect expression of IL-17RB, IL-17RA and bFGF by human vascular endothelial cells (HUVEC) and immunoreactivity for IL-25 and bFGF in asthmatic bronchial biopsies. Receptor-blocking antibodies, PCR and an in vitro angiogenesis assay were used to investigate whether IL-25 acts on IL-17RB or IL-17RA to induce bFGF expression and angiogenesis. PCR was also employed to investigate the signalling pathways involved in IL-25-mediated bFGF expression.

RESULTS

HUVEC constitutively expressed IL-17RB, IL-17RA and bFGF. Production of the latter was further increased by IL-25, but attenuated after blockade of the IL-17RB, but not the IL-17RA receptor. Neutralization of endogenous VEGF and bFGF completely abrogated IL-25-induced angiogenesis which was also inhibited by blocking IL-17RB, but not IL-17RA. The PI3K-specific inhibitor LY294002 also completely attenuated IL-25-induced bFGF expression. Immunoreactivity for IL-25 and bFGF was elevated in the asthmatic bronchial mucosa and the expression of each correlated with the other.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data support the hypothesis that IL-25 contributes to elevated bFGF in asthmatic airways by acting on the endothelial cell IL-17RB receptor through PI3K-signalling pathways. Targeting the pathways might benefit therapy of airways remodelling.

Further results on adaptive control for a class of nonlinear systems using neural networks

Zhang et al. presented an excellent neural-network (NN) controller for a class of nonlinear control designs. The singularity issue is completely avoided. Based on a modified Lyapunov function, their lemma illustrates the existence of an ideal control which is important in establishing the NN approximator. In this paper, we provide a Lyapunov function to realize an alternative ideal control which is more direct and simpler. The major contributions of this paper are divided into two parts. First, it proposes a control scheme which results in a smaller dimensionality of NN than that of Zhang et al. In this way, the proposed NN controller is easier to implement and more reliable for practical purposes. Second, by removing certain restrictions from the design reported by Zhang et al., we further develop a new NN controller, which can be applied to a wider class of systems.

Endoscopic submucosal dissection with sentinel node navigation surgery for early gastric cancer

We combined endoscopic submucosal dissection (ESD) and sentinel node navigation surgery with the purpose of achieving complete resection of early gastric cancer while preserving the organ and assessing pathological nodal status. A total of 13 patients with cT1( ≤ 3 cm)N0 early gastric cancer underwent combined ESD and sentinel node navigation surgery (ESN) at a single tertiary referral center. Sentinel node navigation surgery using indocyanine green was performed during ESD and all suspected sentinel nodes were removed laparoscopically and examined intraoperatively. ESN was converted to gastrectomy with D2 dissection if there was evidence of metastasis on frozen section. ESN was completed in 12 patients and in 1 patient was converted to gastrectomy after sentinel node navigation surgery. En bloc tumor resection was achieved in all cases. Two patients underwent additional gastrectomy because they had tumor-positive vertical margins. In all cases ESN was conducted without intraoperative or postoperative adverse events. ESN is a feasible minimally invasive procedure that allows en bloc tumor resection to be achieved while assessing the pathological status of the lymph nodes.

Direct peroral cholangioscopy using an ultraslim upper endoscope for management of residual stones after mechanical lithotripsy for retained common bile duct stones

BACKGROUND AND STUDY AIMS

The incidence of residual stones after mechanical lithotripsy for retained common bile duct (CBD) stones is relatively high. Peroral cholangioscopy using a mother-baby system may be useful for confirming complete extraction of stones, but has several limitations regarding routine use. We evaluated the role of direct peroral cholangioscopy (DPOC) using an ultraslim upper endoscope for the evaluation and removal of residual CBD stones after mechanical lithotripsy.

PATIENTS AND METHODS

From August 2006 to November 2010, 48 patients who had undergone mechanical lithotripsy for retained CBD stones with no evidence of filling defects in balloon cholangiography were recruited. The bile duct was inspected by DPOC after balloon cholangiography. Detected residual CBD stones were directly retrieved with a basket or balloon catheter under DPOC. The incidence of residual stones detected by DPOC, and the success rate of residual stone retrieval under DPOC were investigated.

RESULTS

DPOC was successfully performed in 46 of the 48 patients (95.8%). Of these, 13 patients (28.3%) had residual CBD stones (mean number 1.4, range 1-3; mean diameter 4.5 mm, range 2.3-9.6). The residual stones were removed directly under DPOC in 11 of these patients (84.6%). There were no complications associated with DPOC or stone removal.

CONCLUSION

DPOC using an ultraslim upper endoscope is a useful endoscopic procedure for the evaluation and extraction of residual stones after mechanical lithotripsy for retained CBD stones.

Functional regeneration of a severed peripheral nerve with a 7-mm gap in rats through the use of an implantable electrical stimulator and a conduit electrode with collagen coating

OBJECTIVE

This paper examined the efficacy of an implantable electrical stimulator in rats for the functional regeneration of peripheral nerves.

MATERIALS AND METHODS

The implantable electrical stimulator was fabricated on a polyimide-based conduit with an integrated electrode, a stimulation chip, and a battery; 3 mg/mL of collagen gel was coated onto the conduit surface and electrical stimulation (20 µ A, 100 µ s, and 100 Hz biphasic current) was continuously applied between the nerve stumps for four weeks. The stimulator was tested on a severed sciatic nerve with a 7-mm gap in rats. The effects of both the electrical stimulation and the collagen application were examined.

RESULTS

Functionality was evaluated through walk track assessments and by recording the action potential of the regenerated nerve. Immunohistochemical staining of the regenerated nerve was done using peripheral myelin protein 22.

CONCLUSION

The results suggest that the functional recovery of a severed peripheral nerve by the proposed implantable electrical stimulator was achieved through electrical current stimulation along the use of a collagen coating on the conduit surface.

Breaking the speed limits of phase-change memory

Phase-change random-access memory (PCRAM) is one of the leading candidates for next-generation data-storage devices, but the trade-off between crystallization (writing) speed and amorphous-phase stability (data retention) presents a key challenge. We control the crystallization kinetics of a phase-change material by applying a constant low voltage via prestructural ordering (incubation) effects. A crystallization speed of 500 picoseconds was achieved, as well as high-speed reversible switching using 500-picosecond pulses. Ab initio molecular dynamics simulations reveal the phase-change kinetics in PCRAM devices and the structural origin of the incubation-assisted increase in crystallization speed. This paves the way for achieving a broadly applicable memory device, capable of nonvolatile operations beyond gigahertz data-transfer rates.

An auto-perfusing umbilical cord blood collection instrument

In this paper, the development of an automated umbilical cord blood (UCB) collection instrument, comprising of mechanical, electronics and control components, is provided in detail. UCB from the placenta provides a rich source of highly proliferative cells for many clinical uses as it contains rich Hematopoietic Stem Cells (HSCs) which yield many benefits over traditional sources such as the bone marrow and periphery blood. Current collection of UCB uses a syringe to extract blood from placenta, which is highly limited in volume and cell numbers. This paper will present the development of an automated UCB collection instrument to yield improved performance which comprised four subsystems. First, a placenta handling system is designed to produce air pressure which can realize the emulation of the uterus compression on the placenta. Second, an auto-medium injector system is presented to enable perfusion automatically. Third, a time window widening system is developed which generates vibrations during the perfusion phase and helps the exposed end of the cord cool down to a low temperature. Finally, a control platform is used to integrate all systems working together, hosting the control algorithms which operate the instrument automatically.

Recanalization with Wingspan stent for acute middle cerebral artery occlusion in failure or contraindication to intravenous thrombolysis: a feasibility study

BACKGROUND AND PURPOSE

Recanalization with the Wingspan stent, which can be deployed rapidly and safely, is an option for treating acute ischemic stroke when intravenous thrombolysis has failed or is contraindicated. This study was performed to evaluate feasibility, efficacy, and safety of recanalization for acute middle cerebral artery occlusion using the Wingspan stent.

MATERIALS AND METHODS

We collected 10 patients with acute MCA occlusion in whom recanalization was not achieved with a standard intravenous thrombolysis, or who were ineligible for intravenous thrombolysis, or who presented after 3 hours of symptom onset and in whom the stent placement could be completed within 8 hours from symptom onset. We analyzed angiographic and clinical results.

RESULTS

Successful recanalization with the Wingspan stent was achieved in all patients. The mean NIHSS score on admission was 12.7 points (range 4-21). The occlusion sites were located in the 1st segment (n = 7; 2 left, 5 right) and 2nd segment (n = 3, all right) of the MCA. The mean time interval from stroke symptom onset to stent placement was 344.8 ± 76.3 minutes. No intracranial hemorrhage, vessel perforations, or dissections occurred in any patient. Nine patients improved on the NIHSS at 7 days. One patient did not have a change in the NIHSS score, even though the occluded artery was completely recanalized. At 7 days, the NIHSS score of all patients was 4.4 ± 4.7 (median 4, range 0-13). At discharge, an mRS of ≤ 3 was achieved in all patients and an mRS of ≤ 2 was achieved in 7 patients (70%).

CONCLUSIONS

This small case series demonstrates the feasibility of using the Wingspan stent safely and effectively for MCA occlusions when standard treatments are ineffective or not available.