Cortical Brain Stimulation with Endovascular Electrodes

Electrical stimulation of neural tissue and recording of neural activity are the bases of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and drug-resistant neurological disorders. Safety and efficacy are key aspects for the clinical acceptance of therapeutic neural stimulators. The cortical vasculature has been shown to be a safe site for implantation of electrodes for chronically recording neural activity, requiring no craniotomy to access high-bandwidth, intracranial EEG. This work presents the first characterization of endovascular cortical stimulation measured using cortical subdural surface recordings. Visual stimulation was used to verify electrode viability and cortical activation was compared with electrically evoked activity. Due to direct activation of the neural tissue, the latency of responses to electrical stimulation was shorter than for that of visual stimulation. We also found that the center of neural activation was different for visual and electrical stimulation indicating an ability of the stentrode to provide localized activation of neural tissue.

Case Report: Necrotising Fasciitis with Epidural Abscess

Necrotising fasciitis is relatively uncommon in Hong Kong. Its rapid progression and deterioration is the reason for high mortality. We report a patient who presented with this condition which was complicated with epidural abscess after incision and drainage. Early recognition is the key to save the patient.

Streptococcus Suis: What Has Been Found in the past Decades?

Streptococcus suis (SS) infection has aroused tremendous attention recently. We report a restaurant worker who suffered acute confusion due to SS meningitis. Sporadic cases have been reported in Hong Kong since 1981. Little was known in the past about its characteristic fulminant clinical deterioration. We explored the literature and discuss the epidemiology, pathogenesis, clinical manifestations and management of this disease.

Sweat and Blood – Runner's Haematuria: Discharge or Further Evaluate?

An elite runner presented with macroscopic haematuria after six hours of non-stop running during his training for Trailwalker. The haematuria resolved after two days of conservative treatment. The history, pathophysiology and complication of runner-related haematuria are discussed. A simplified management plan is suggested in order to avoid unnecessary anxiety to the patients, inappropriate referral and wasting of medical resources.

Evaluation of a Commercial Phantom and Pork Meat Model for Simulation Based Training of Ultrasound Guided Intravenous Catheterisation

Introduction

Establishing intravenous access is a common procedure being performed in the emergency department. Ultrasound guidance is useful for difficult intravenous cannulation. We compared a commercially available Blue Phantom™ and a self-made pork meat model for suitability of simulation based training.

Methods

We recruited emergency physicians from two public regional hospitals in our locality. We also recruited Myanmar emergency physicians from an ultrasound course. They were given a 30-minute hands-on practice on both phantoms. Questionnaires, which asked about the practical feeling and overall impression of both phantoms, were distributed afterwards.

Results

Thirty-nine emergency physicians with varied experience in ultrasound guided intravenous catheterisation enrolled in the study. The median score were 4 (i.e. agree) in seven out of eight pairs of questions. The practical feeling and overall personal impression were very similar between Blue Phantom™ and pork meat model.

Conclusions

The suitability of self-made pork meat model was similar to Blue Phantom™ for the training of ultrasound guided IV catheterisation. Pork meat model can used as an alternative training tool. (Hong Kong j.emerg.med. 2016;23:153-158)

Case Report: Acute Inferior Myocardial Infarction with Single-Lead ST Segment Elevation

This article illustrates a patient who presented with acute inferior myocardial infarction with only isolated ST segment elevation in Lead III. Brief review on the electrocardiographic interpretation was discussed. Early recognition and management is the key to prevent morbidity and mortality.

New Era of CPR: Application of I-Technology in Resuscitation

Introduction

The present study evaluated the performance and acceptance of a cardiopulmonary resuscitation (CPR) feedback application for the iPhone (“PocketCPR®”) designed to improve chest compression performance.

Methods

We randomly assigned participants into two groups to perform chest compression with (study group) or without (control group) using the “PocketCPR®” on a manikin. The participants performed totally four sets of chest compression simulating two CPR scenarios. In the first scenario, no advanced airway was inserted while in the second scenario, advanced airway was inserted. We measured and compared the rate and depth of chest compression between the groups in both scenarios. Participants in study group also finished a questionnaire on the use of feedback application.

Results

The mean compression depth of the study group was significantly deeper both in the first scenario (5.22 cm; 4.56 cm, p=0.002; 5.30 cm; 4.56 cm, p=0.001) and the second scenario (5.34 cm; 4.56 cm, p<0.001; 5.35 cm; 4.49 cm, p<0.001). However, the mean compression rate of study group was significantly slower than the control group both in the first scenario (105.19; 118.58, p<0.001; 105.23; 119.36, p<0.001) and the second scenario (106.10; 121.08, p<0.001, 106.61; 117.42, p=0.002).

Conclusion

A mobile phone feedback application “PocketCPR®” improves chest compression quality by increasing the compression depth in laboratory setting. Further study is indicated to demonstrate its benefit in clinical setting.

New Horizon on Community-Acquired Methicillin Resistant Staphylococcus Aureus (Ca-Mrsa) Skin and Soft Tissue Infection: Nanotechnology Antimicrobial Spray

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in community and hospital is increasing. The development of drug resistance may be attributed to the extensive use of antibiotics. Nanotechnology antimicrobial spray (NTAS), a physical antibacterial agent, is an alternative to antibiotic treatment on wound management. We report a case of MRSA associated skin abscess using NTAS in the wound management. NTAS possesses potent, broad spectrum antibacterial effect while carrying no risk of resistance and minimal adverse effect. Moreover, NTAS facilitates home wound management, thus reducing dependency on public health resources. Further studies are indicated to explore the clinical role of NTAS in an attempt to reduce the use of antibiotics. (Hong Kong j.emerg.med. 2011;18:432-436)

Diagnostic Challenges: Pseudo-Phenomenon in Wolff-Parkinson-White Syndrome

We reported two patients who presented with non-specific chest symptoms with ECG changes mimicking acute myocardial infarction and ventricular hypertrophy. Both of them were finally confirmed to have Wolff-Parkinson-White (WPW) syndrome after spontaneous resolution of the ECG changes. As a matter of fact, other differential diagnosis should be considered with respect to the ST-segment changes. Diagnostic pitfalls can be avoided by detailed analysis of the ECG before commencement of thrombolytic agents.

Spontaneous Lateral Abdominal Wall Haematoma Presenting with Grey-Turner'S Sign

We describe a 93-year-old patient presenting with Grey-Turner's sign due to spontaneous lateral abdominal wall haematoma. It is a rare entity. Bedside high resolution ultrasound scan is valuable in the emergency setting to investigate a patient with Grey-Turner's sign. CT abdomen often confirms the diagnosis. These haematoma are usually benign but can have fatal complications. Management may vary from conservative treatment to intravascular embolisation or open evacuation with ligation of the bleeding vessel.

Presentations of Runners in Kong Kong Marathon to a Local ED: A 10 Years' Glance

Objective

To determine the basic characteristics, presentations, diagnoses and critical outcomes (heat Stroke, heat exhaustion, post-cardiac arrest and acute coronary syndrome) of patients in Accident and Emergency Department (AED) of Ruttonjee and Tang Shiu Kin Hospital (RHTSK) who participated in Hong Kong Marathon from 2003 to 2012.

Methodology

This was a simple descriptive epidemiology study to analyze patients who were participants of Hong Kong Marathon and attended AED of RHTSK for any complaint during or after the event.

Results

There were a total 170 participants who attended AED of RHTSK in these ten years; in which, 74.1% were male, with a mean (SD) age of 38.08 (11.29). Totally, 77.1% were non-trauma cases and 46.5% were critical/urgent cases (category in AED triage 1-3). Among all cases, 31.8% required admission, 4.1% were care in intensive care unit (ICU), 12.4% were managed in resuscitation room and 3.5% required intubation. The majority of cases were heat stroke and heat exhaustion. There were 4 cases of post cardiac arrest, 3 of them admitted to ICU after successful resuscitation. Number of critical/urgent cases increased with apparent temperature on Marathon Day. The correlation coefficient of percentage of critical/urgent cases with apparent temperature was 0.827 (p=0.011).

Conclusion

Total number of participants increased dramatically in Hong Kong Marathon throughout these ten years, participants' required medical attendance and emergency service also increased respectively. Number of critical/urgent cases increased with apparent temperature on Marathon Day. The majority of cases were heat-related illness, 4 cases presented with post cardiac arrest and one failed in resuscitation. (Hong Kong j.emerg.med. 2014;21:197-204)

A Young Man with Sudden Unilateral Blindness and Hemiparesis

Head and neck injuries are very common in Hong Kong, especially resulting from assaulted or traffic accidents. Delayed manifestation of post-traumatic carotid thrombo-embolism and aneurismal formation are known pitfalls that emergency physicians and neurosurgeons may encounter. We present a patient with blunt neck injury with the complication of traumatic dissection of the extracranial internal carotid artery.

The effect of dichloroacetate on health- and lifespan in C. elegans

Aging is associated with increased vulnerability to chronic, degenerative diseases and death. Strategies for promoting healthspan without necessarily affecting lifespan or aging rate have gained much interest. The mitochondrial free radical theory of aging suggests that mitochondria and, in particular, age-dependent mitochondrial decline play a central role in aging, making compounds that affect mitochondrial function a possible strategy for the modulation of healthspan and possibly the aging rate. Here we tested such a "metabolic tuning" approach in nematodes using the mitochondrial modulator dichloroacetate (DCA). We explored DCA as a proof-of-principle compound to alter mitochondrial parameters in wild-type animals and tested whether this approach is suitable for reducing reactive oxygen species (ROS) production and for improving organismal health- and lifespan. In parallel, we addressed the potential problem of operator bias by running both unblinded and blinded lifespan studies. We found that DCA treatment (1) increased ATP levels without elevating oxidative protein damage and (2) reduced ROS production in adult C. elegans. DCA treatment also significantly prolonged nematode health- and lifespan, but did not strongly impact mortality doubling time. Operator blinding resulted in considerably smaller lifespan-extending effects of DCA. Our data illustrate the promise of a "metabolic tuning" intervention strategy, emphasize the importance of mitochondria in nematode aging and highlight operator bias as a potential confounder in lifespan studies.

Prospective, randomized, controlled trial comparing lightweight versus heavyweight mesh in chronic pain incidence after TEP repair of bilateral inguinal hernia

BACKGROUND

This prospective, clinical, randomized, controlled study was performed to define the incidence of chronic pain after total extraperitoneal (TEP) repair with a light-weighted mesh compared with heavyweight mesh in patients with bilateral inguinal hernias.

METHODS

Consecutive patients with bilateral inguinal hernias were recruited for TEP inguinal hernia repair under general anesthesia. Heavyweight mesh was randomly assigned to one side of the groin and lightweight mesh to the other. Patients were followed up regularly for up to 1 year by an independent surgeon who was unaware of the mesh assignment. The postoperative pain score by means of a visual analogue scale (VAS) and other data were recorded.

RESULTS

Fifty bilateral TEP hernia repairs were performed between September 2007 and February 2009. Six patients (12%) complained of chronic pain 3 months after the operation. A higher average pain score was observed for the side of hernia repaired by heavyweight mesh compared with lightweight mesh, but the difference was not statistically significant. More patients complained about foreign body sensation on the side repaired with heavyweight mesh (24%) compared with the side with lightweight mesh (8%; P < 0.05). There was no recurrence or need for reintervention for either type of mesh.

CONCLUSIONS

Lightweight polypropylene mesh may be preferable to heavyweight mesh for TEP inguinal hernia repair because it provides less postoperative foreign body sensation; however, there was no significant difference in the incidence of chronic pain.

A CMOS retinal neurostimulator capable of focussed, simultaneous stimulation

Restoring vision to the blind by way of medical device technology has been an objective of several research teams for a number of years. It is known that spots of light-phosphenes-can be elicited by way of electrical stimulation of surviving retinal neurons. Beyond this our understanding of prosthetic vision remains rudimentary. We have designed and manufactured an integrated circuit neurostimulator with substantial versatility, able to provide focussed, simultaneous stimulation using current sources and sinks, steering the current to the intended site of stimulation. The ASIC utilizes high-voltage CMOS transistors in key circuits, to manage voltage compliance issues (due to an unknown or changing electrode/tissue interface impedance) given the relatively high stimulation thresholds necessary to elicit physiological excitation of retinal neurons. In addition, a unique multiplexing system comprised of electrodes arranged in a hexagonal mosaic is used, wherein each electrode can be addressed to be a stimulating electrode and all adjacent electrodes serve as the return path. This allows for simultaneous stimulation to be delivered while appropriately managing cross-talk between the stimulating electrodes. Test results indicate highly linear current sources and sinks (differential nonlinearity error of 0.13 least significant bits -2.6 microA), with the ASIC clearly able to provide focussed stimulation using electrodes immersed in a saline solution.

Charge recovery during concurrent stimulation for a vision prosthesis

Parallel or concurrent stimulation in an epiretinal neuroprosthesis is likely necessary in order to deliver sufficient phosphenes for effective vision. Important issues with concurrent stimulation are the effect of current distribution which introduces current leakage or 'cross talk' between adjacent electrodes and charge recovery which determines balanced charge being delivered/recovered at each electrode from the previous phase. In this paper, we present the effect of concurrent stimulation of two hexagonally arranged platinum electrode arrays on charge recovery. Balanced and imbalanced (unequal) currents were delivered to the hexagonal arrays when they were immersed in physiological saline. Both simulation and experimental results revealed that charge was not recovered at individual electrodes, particularly when imbalanced currents were delivered. However, total charge injected to both hexagonal arrays was recovered.

Effect of maternal age, birth weight and infant sex on total nucleated cell (TNC) count and volume of umbilical cord blood (UCB) collected

This study evaluates the effect of maternal age, birth weight and infant sex on two main UCB parameters for use and long-term cryopreservation: TNC and volume. Data from 1000 UCB units were collected and analyzed in this study. The results indicate that TNC is correlated to infant birth weight and sex but not maternal age at delivery. Volume is only correlated to birth weight but not maternal age and infant sex.

Incomplete cellular depopulation may explain the high failure rate of bovine ureteric grafts

BACKGROUND

The aim was to assess the results of a decellularized bovine ureter graft (SynerGraft) for complex venous access.

METHODS

Bovine ureter conduits were implanted in patients with a failed fistula or access graft in whom native vessels were unsuitable as conduits. Graft histories were obtained from all patients who had undergone this procedure at one institution. Failed grafts were explanted and subjected to histological examination. A sample of fresh bovine ureter was immunostained for galactose (alpha1 --> 3) galactose (alpha-Gal).

RESULTS

Nine patients with a median age of 46 (range 25-70) years underwent complex venous access surgery between August 2004 and November 2006 using a SynerGraft. Graft types included loop superficial femoral artery to stump of long saphenous vein (four patients), loop brachial artery to vein (two), brachial artery to axillary vein (two) and left axillary artery to innominate vein (one). Three grafts developed aneurysmal dilatation and two thrombosed. Histological assessment of the explanted bovine ureters revealed acute and chronic transmural inflammation. Immunostaining of fresh bovine ureter suggested residual cells and the xenoantigen alpha-Gal.

CONCLUSION

Graft failure with aneurysmal dilatation and thrombosis in complex arteriovenous conduits using bovine ureter may be due to residual xenoantigens.

Microelectronic retinal prosthesis: I. A neurostimulator for the concurrent activation of multiple electrodes

An application specific integrated circuit (ASIC) capable of delivering charge to multiple electrodes in unison has been developed. The ASIC is designed to function as part of an epi-retinal prosthesis driving an array of electrodes in a hexagonal mosaic. This unique organization of electrodes and the use of current sources and sinks is implemented to reduce the electrical cross-talk that occurs when many electrodes are activated in unison. Due to the large numbers of electrodes needed to provide useful vision to implantees, the interleaving strategies used in cochlear implants will not suffice for a vision prosthesis, where the "frame rate" is important for acceptable perceptual outcomes. This paper describes the design, and architectural approaches and performance testing of the developed ASIC.

The design and testing of an epi-retinal vision prosthesis neurostimulator capable of concurrent parallel stimulation

An application specific integrated circuit (ASIC) neurostimulator capable of stimulating multiple electrodes in unison has been designed and tested. The ASIC utilizes multiple matched current sinks and sources to provide localized stimulation and is designed to drive electrodes organized in a hexagonal mosaic. This organization allows each stimulating electrode to be surrounded by up to six return electrodes, effectively isolating each stimulation site. The ASIC was manufactured using a high-voltage complementary metal-oxide-semiconductor process, which allows up to 20 V to be applied across the circuitry. This provides the greatest versatility for testing with electrodes and tissues of varying impedances in-situ and allows the device to be used in other neurostimulation applications such as functional electrical stimulation. The design has been thoroughly tested and meets all the design specifications.

Efficacy of supra-choroidal, bipolar, electrical stimulation in a vision prosthesis

The key to successful, clinical application of therapeutic neurostimulators lies primarily with the safety and efficacy of their electrode-tissue interfaces. The authors posit that for electrical stimulation of the visual system, supra-choroidal electrode placement provides a safe, stable and readily-accessible site for implantation and the provision of electrical stimulation. The present paper explores the efficacy of supra-choroidal electrical stimulation of retinal neurons. Based upon recordings made with surface electrodes placed on the primary visual cortex, areas of activation in the cortex were shown to change when different areas on the supra-choroidal space were stimulated. Finally, the threshold to elicit a response from neurons in the visual cortex, was found to be 77.55 +/- 29.85 nC.

Microelectronic retinal prosthesis: II. Use of high-voltage CMOS in retinal neurostimulators

This paper presents the design, implementation, and simulated and measured results of a complementary metal-oxide-semiconductor neurostimulator implemented in a 0.35 microm high-voltage process. To allow for a high stimulation voltage, and hence the greatest versatility of the neurostimulator in situ, a high-voltage CMOS process was used. The neurostimulator utilized current sources and sinks to simultaneously deliver and recover charge. It has the ability to deliver stimulus in three output current ranges using a current sink only, current source only, or both a current source and sink combined to provide focused stimulation. The worst case integral non-linearity and differential non-linearity errors were 0.2 LSB and 0.1 LSB respectively, and the current source and sink turn-on times were under 500 ns, providing fast switching time in response to stimuli instructions. The total die area was under 13 mm2, well within the area constraints of our implantable vision prosthesis device.

Anti-vimentin Antibody Detection in Recipients of Heart-Beating and Non–Heart Beating Donor Kidneys

Alternative donor sources include non-heart-beating donors (NHBDs). There donors have been exposed to significant ischemia, so that it is common to utilize machine perfusion to either improve the organs or at least assess their viability. Both prolonged warm ischemia and machine perfusion can potentially damage the vascular endothelium, thereby exposing vimentin to antigenic recognition. The aim of this study was to determine whether anti-vimentin antibodies could be detected in the blood of renal transplant recipients at specific time points after transplant and whether they could be related to the donor source. Fifty-one recipients of NHBD kidneys were compared to 52 recipients of heart-beating donor (HBD) kidneys. All recipients had similar anti-vimentin levels pretransplant. However, at 1 month those kidneys from Maastricht category II NHB donors showed significantly higher levels. At 6 months both Maastricht category II and category III NHB donor recipients displayed significantly higher levels than recipients of HBD kidneys.

Audit of Diabetes in a Renal Transplant Population

AIMS

To determine the prevalence of diabetes and its glycemic control in the renal transplant population of northeast England (Newcastle, Sunderland, Middlesborough, and Carlisle).

METHODS

All renal transplant notes in northeast England were reviewed. Data on patient details, type of diabetes, time of onset of diabetes, diabetes medications, time of insulin commencement, date of renal transplant, immunosuppressive medications, and HbA(1C) were recorded.

RESULTS

Living renal transplant patients (n = 1073) transplanted between March 1982 and November 5, 2003 were identified. One hundred and nine (10.2%) patients had diabetes, of whom 39 were type 1 and 70 were type 2. Median HBA(1C) in patients with type 1 diabetes on tacrolimus was 10.1% +/- 1.94% (SD) versus 7.8% +/- 1.98% (SD) for patients not on tacrolimus. Among patients with type 2 diabetes, 25 had diabetes prior to transplant and 45 (4.5%) developed posttransplant diabetes (PTDM). Those who developed PTDM and were taking tacrolimus were more likely to require insulin for blood glucose control (0.39 U/kg/24 hours vs 0 U/kg/24 hours; P = .05) compared to those not on tacrolimus. Both type 1 and type 2 diabetics on tacrolimus showed better preservation of renal function as measured by mean serum creatinine (type 1: 145 +/- 53 vs 196 +/- 74, P = .02; type 2 pretransplant: 159 +/- 73 vs 172 +/- 59, P = .35; type 2 posttransplant: 123 +/- 35 vs 167 +/- 63, P = .01).

CONCLUSIONS

Tacrolimus use in renal transplant patients with diabetes appeared to be associated with more problematic blood glucose control; however, it seemed to be better at preserving renal function. Intensive blood glucose monitoring is recommended for this group.

Peritoneal pH during laparoscopy is dependent on ambient gas environment: helium and nitrous oxide do not cause peritoneal acidosis

BACKGROUND

Little is know about the effects of different insufflation gases on peritoneal pH during laparoscopy. However, these changes may influence the intracellular signalling system, resulting in altered cell growth or adhesiveness. The aim of this study was to determine the effects of carbon dioxide (CO(2)), nitrous oxide (N(2)O), and helium (He) on parietal and visceral peritoneal pH. The effect of different intraabdominal pressures on parietal and visceral peritoneal pH was also examined.

METHODS

We conducted both an ambient gas study and a pressure study. For the ambient gas study, 20 pigs were divided into the following four groups: (a) CO(2), (b) He, (c) N(2)O, and (d) abdominal wall lift (Lift) laparoscopy. Parietal and visceral peritoneal pH were measured at 15 min intervals for 180 min. For the pressure study, 15 pigs were divided into the following three groups: (a) CO(2), (b) He, (c) N(2)O laparoscopy. Baseline values were established for parietal and visceral peritoneal pH. Intraabdominal pressure was then increased stepwise at 1-mmHg intervals to 15 mmHg. After pressure was maintained for 15 min at each setting, parietal and visceral peritoneal pH were measured.

RESULTS

Ambient gas environment was the major determinant of parietal peritoneal pH. Carbon dioxide caused parietal peritoneal acidosis. Helium, N(2)O, and Lift caused alkalotic parietal peritoneal pH. Intraabdominal pressure had a minor effect on parietal peritoneal pH. At higher intraabdominal pressure (12-15 vs 5-8 mmHg), CO(2) caused a slight decrease in parietal peritoneal pH, whereas N(2)O and He caused a slight increase in parietal peritoneal pH. Visceral peritoneal pH remained relatively unaffected during all studies.

CONCLUSIONS

Parietal peritoneal pH during laparoscopy was highly dependent on the ambient gas environment. The effect of intraabdominal pressure on parietal peritoneal pH was of minor significance. Carbon dioxide caused a slight worsening of parietal peritoneal acidosis at higher intraabdominal pressure, whereas, N(2)O, He, and Lift did not cause parietal peritoneal acidosis.

Carbon dioxide pneumoperitoneum causes severe peritoneal acidosis, unaltered by heating, humidification, or bicarbonate in a porcine model

BACKGROUND

Carbon dioxide (CO(2)) is the most common gas used for insufflation in laparoscopy, but its effects on peritoneal physiology are poorly understood. This study looks at the changes in peritoneal and bowel serosal pH during CO(2) pneumoperitoneum, and whether heating and humidification with or without bicarbonate alters the outcomes.

METHODS

Twenty-one pigs divided into four groups as follows: (1) standard (STD) laparoscopy (n = 5); (2) heated and humidified (HH) laparoscopy (n = 6); (3) heated and humidified with bicarbonate (HHBI) laparoscopy (n = 5); and (4) laparotomy (n = 5). Peritoneal pH, bowel serosal pH, and arterial blood gas (ABG) were obtained at 15-min intervals for 3 h.

RESULTS

Severe peritoneal acidosis (pH range 6.59-6.74) was observed in all laparoscopy groups, and this was unaltered by heating and humidification or the addition of bicarbonate. Bowel serosal acidosis was observed in all laparoscopy groups with onset of pneumoperitoneum, but it recovered after 45 minutes. No significant changes in peritoneal or bowel serosal pH were observed in the laparotomy group.

CONCLUSION

CO(2) pneumoperitoneum resulted in severe peritoneal acidosis that was unaltered by heating and humidification with or without bicarbonate. Alteration in peritoneal pH may conceivably be responsible for providing an environment favorable for tumor-cell implantation during laparoscopy.

Gastric outlet obstruction secondary to pancreatic cancer: surgical vs endoscopic palliation

BACKGROUND

Gastric outlet obstruction in patients with pancreatic cancer has a grim prognosis. Open surgical bypass is associated with high morbidity, whereas endoscopic duodenal stenting appears to provide better palliation.

METHODS

We reviewed the medical records of patients with gastric outlet obstruction secondary to pancreatic carcinoma who were admitted to our clinic between 1 October 1988, and 30 September 1998. The data included stage of disease, American Society of Anesthesiologists (ASA) class, surgical interventions, complications, and survival.

RESULTS

A total of 250 patients with pancreatic cancer were identified. Twenty-five of them (10%) had gastric outlet obstruction. Of these 25, 17 were treated with gastrojejunostomy, six had duodenal stenting (Wallstent), and two were resectable. There was no significant difference between the gastrojejunostomy group and the duodenal stenting group in ASA class or stage of disease. For the gastrojejunostomy group, median survival was 64 days (range, 15-167) and postoperative stay in hospital was 15 days (range, 8-39). For the duodenal stenting group, median survival was 110.5 days (range, 42-212) and postoperative stay was 4 days (range, 2-6). Ten patients (58.8%) in the gastrojejunostomy group had delayed gastric emptying. All of the patients in the duodenal stenting group were able to tolerate a soft diet the day after stent placement. Thirty-day mortality in the gastrojejunostomy group was 17.64%; in the duodenal stenting group, it was 0.

CONCLUSION

In pancreatic carcinoma patients with gastric outlet obstruction, duodenal stenting results in an earlier discharge from hospital and possibly improved survival.

Effects of antecedent order and semantic context on Chinese pronoun resolution

Three reading time experiments were conducted in order to examine the relative contributions of order of antecedents and semantic context to the resolution of temporarily ambiguous Chinese pronouns. These pronouns were ambiguous because each of them was preceded by two antecedents, both of which were likely candidates for coreference. The identity of the pronoun was revealed by subsequent disambiguating information that constrained the pronoun to one particular interpretation. Experiment 1 showed that reading of the disambiguating phrase was slower when the phrase confined the pronoun to the second rather than to the first antecedent. Experiment 2 produced the same effect of antecedent order (first vs. second antecedent) regardless of whether the target antecedent was an action-performing or an action-receiving entity. In Experiment 3, the order effect was eliminated by a biasing modifier inserted immediately before the pronoun. These results indicate that in a semantically neutral environment, the first-appearing antecedent is the preferred candidate for coreferencing the ambiguous Chinese pronoun. The interaction between order of antecedents and semantic context (in the form of preposed biasing modifiers) suggests that the initial comprehension of Chinese pronouns depends as much on contextual as on structural factors.

Use of skin staples for fixation of T tubes and drains

Stapled anchorage is safe and effective for T tubes and drains and is preferred to the conventional technique. Significant bile leaks never occur. Three and two staples are recommended for anchoring T tubes and drains, respectively.

Direct demonstration of membrane IL-1 alpha on the surface of circulating B lymphocytes and monocytes

A mAb against IL-1 alpha has been used in a high sensitivity immunofluorescence procedure to demonstrate directly the presence of surface IL-1 alpha on human monocytes and B cells from blood and tonsil. IL-1 alpha could be detected on monocytes and a subset (around 30%) of B cells without any in vitro activation. Although the subset of B cells expressing IL-1 alpha was distinct (i.e., the distribution of fluorescence intensity was bimodal), no correlation was seen with any other B cell subset marker in blood. In tonsil, IL-1 alpha was expressed by cells with a phenotype that suggested that they represented a subset of mantle zone B cells. Activation of tonsil B cells with anti-IgM, IL-4, IL-2, and mixtures of these reagents led to small increases in IL-1 alpha expression, as did activation of unfractionated tonsil cells with PHA.

Direct demonstration of membrane IL-1 alpha on the surface of circulating B lymphocytes and monocytes

A mAb against IL-1 alpha has been used in a high sensitivity immunofluorescence procedure to demonstrate directly the presence of surface IL-1 alpha on human monocytes and B cells from blood and tonsil. IL-1 alpha could be detected on monocytes and a subset (around 30%) of B cells without any in vitro activation. Although the subset of B cells expressing IL-1 alpha was distinct (i.e., the distribution of fluorescence intensity was bimodal), no correlation was seen with any other B cell subset marker in blood. In tonsil, IL-1 alpha was expressed by cells with a phenotype that suggested that they represented a subset of mantle zone B cells. Activation of tonsil B cells with anti-IgM, IL-4, IL-2, and mixtures of these reagents led to small increases in IL-1 alpha expression, as did activation of unfractionated tonsil cells with PHA.