Liquid biopsy of oesophageal squamous cell carcinoma: implications in diagnosis, prognosis, and treatment monitoring

Oesophageal squamous cell carcinoma (ESCC) is a common malignant tumour of the gastrointestinal tract. Early detection and access to appropriate treatment are crucial for the long-term survival of patients. However, limited diagnostic and monitoring methods are available for identifying early stage ESCC. Endoscopic screening and surgical resection are commonly used to diagnose and treat early ESCC. However, these methods have disadvantages, such as high recurrence, lethality, and mortality rates. Therefore, methods to improve early diagnosis of ESCC and reduce its mortality rate are urgently required. In 1961, Gary et al. proposed a novel liquid biopsy approach for clinical diagnosis. This involved examining exosomes, circulating tumour cells, circulating free DNA, and circulating free RNA in body fluids. The ability of liquid biopsy to obtain samples repeatedly, wide detection range, and fast detection speed make it a feasible option for non-invasive tumour detection. In clinical practice, liquid biopsy technology has gained popularity for early screening, diagnosis, treatment efficacy monitoring, and prognosis assessment. Thus, this is a highly promising examination method. However, there have been no comprehensive reviews on the four factors of liquid biopsy in the context of ESCC. This review aimed to analyse the progress of liquid biopsy research for ESCC, including its classification, components, and potential future applications.

[Correlation between postoperative microstructural changes in cerebral white matter and early postoperative cognitive function in patients undergoing meningioma resection]

Objective: To analyze the correlation between microstructure changes in cerebral white matter before and after surgery and early postoperative cognitive function in patients undergoing meningioma resection. Methods: A total of 17 patients who underwent their first meningioma resection at Xuanwu Hospital of Capital Medical University from April 2022 to April 2023 were prospectively included as observation group, with 5 males and 12 females, aged (56.4±7.3) years. Another 15 age- and education-matched patients with cerebral benign tumor were recruited as control group during the same period, with 5 males and 10 females, aged (55.2±8.0) years. Neuropsychological tests (NST), mainly including auditory verbal learning test of Huashan version (AVLT-H), the Montreal cognitive assessment-basic (MoCA-B), clock drawing task-30 (CDT-30), shape trails test-B (STT-B) and animal fluence test (AFT), were conducted at 1 day before surgery, 1 day and within 3-4 days after surgery in the observation group. Simultaneously, magnetic resonance imaging (MRI) scans were performed to collect diffusion tensor imaging (DTI) images at 1 day before surgery and within 3-4 days after surgery. The same NST were conducted at 1 day, 3 days and 6 days after admission in the control group to adjust for learning effects from repeated tests. The microstructure changes of the whole brain white matter were evaluated at the group level by using tract-based spatial statistics (TBSS) technology, including changes of fractional anisotropy (FA), mean diffusion (MD), axial diffusion (AD), and radial diffusion (RD). Then, correlation was performed between DTI indicators with statistically significant and cognitive function. Results: After adjusting for the learning effects, the AVLT-H (R), MoCA-B, and CDT-30 scores decreased, and the evaluation time of STT-B prolonged after surgery in patients with meningioma. And their perioperative decreased values were -0.78 (95%CI:-3.28--0.28) points, -2.22 (95%CI:-4.22--0.72) points, -2.74 (95%CI:-5.29--0.19) points, and 61.49 (95%CI: 5.71-117.27) seconds, respectively, with statistically significant differences (all P<0.05). Group level analysis of TBSS based on DTI images showed decreased FA mainly in the right superior cerebellar peduncle, left posterior limb of internal capsule and genu of corpus callosum, and increased RD mainly in the left anterior corona radiata in patients undergoing meningioma resection, with statistically significant differences (all PFWE<0.05). Linear correlation showed that the perioperative decreased values of FA in genu of corpus callosum and right superior cerebellar peduncle were positively correlated with the perioperative decreased values of AVLT-H (L) after adjusting for learning effects (r=0.72, 0.52, all PFWE<0.05). Conclusions: Patients undergoing meningioma resection are at risk of postoperative cognitive decline. Perioperative decreased values of FA in genu of corpus callosum and right superior cerebellar peduncle based on DTI images are positively correlated with the perioperative decreased values of AVLT-H (L) after adjusting for learning effects.

[The ventilation efficacy and safety of new nasopharyngeal airway applied in left atrial appendage occlusion]

Objective: The present retrospective study aimed to analyses the ventilation efficacy and safety of new nasopharyngeal airway applied in left atrial appendage occlusion. Methods: A total of 37 advanced aged patients diagnosed with atrial fibrillation(>65 years)who underwent left atrial appendage occlusion (LAAO) in Xuanwu Hospital of Capital Medical University from March 2021 to March 2022 were enrolled in this study. All patients received supplemental oxygen by a new nasopharyngeal airway to ensure intraoperative ventilation. The primary outcome was the occurrence of hypoxemia. The secondary outcomes included the incidence of hypotension after anesthesia, the incidence of body movement during surgery, significant fluctuations of the vital signs such as mean arterial pressure (MAP), heart rate (HR), saturation of pulse oxygen (SpO2) and respiratory rate (RR) at different time points (T1: pre-operation; T2: at the time of placing nasopharyngeal airway; T3: at the time of placing transesophageal echocardiography(TEE); T4: at the time of TEE intraoperative exploration; T5: end of the surgery; T6: at the time of patient woke up), and the incidence of postoperative adverse events. Results: There were 24 males and 13 females with a mean age of (73.8±7.7) years. The incidence of hypoxemia was 16.2% (6/37), which could return to normal after simple treatment. The incidence of hypotension was 27.0% (10/37), occurred after anesthesia induction mainly.32.4% (12/37) of the patients experienced movements, but no adverse events led to surgical termination. MAP at different time points was significantly different (P=0.001), but other vital signs of HR, SpO2 and RR were not significantly different(all P>0.05), without serious hemodynamic fluctuations. The incidence of postoperative adverse cardiovascular events was 10.8% (4/37), and delirium was 2.7% (1/37). All patients successfully completed the surgery and were safely discharged from the hospital. Conclusion: The new nasopharyngeal airway can meet the requirements of airway management during left atrial appendage occlusion under intravenous anesthesia without serious adverse events.

[Accelerating the transformation from anesthesia clinic to comprehensive anesthesia and multi-disciplinary evaluation, consultation, pre-rehabilitation and follow-up center in outpatient under aged society]

The acceleration of aging process in China bring challenges for the anesthesia management of elderly patients. The co-morbidity, decreased function and high risk of postoperative severe complications and mortality are the main reasons of resultant lower anesthesia and surgery rate,higher medical expenses for elderly patients. The transformation from anesthesia clinic service to comprehensive anesthesia and multi-disciplinary evaluation, consultation,pre-rehabilitation and follow-up center in outpatient is a new medical mode to resolve the problem, which depends on the collaboration among hospital, disciplines and government to undertake the task.

[The applications and challenges of combined monitoring of macro/micro-circulation and mitochondrial homeostasis in early warning of perioperative organ injury]

Perioperative organ injury is a leading risk factor for mortality in surgical patients. Given the current limitations in the timeliness and accuracy of markers for perioperative organ injury, this article proposes a comprehensive early-warning assessment system that jointly monitors the macro-circulation, micro-circulation, and mitochondrial homeostasis. Macro-circulation monitoring allows for real-time evaluation of key indicators such as blood pressure and cardiac output, while micro-circulation monitoring aids in assessing the status of microvascular perfusion. Monitoring of mitochondrial homeostasis provides timely insights into cellular energy metabolism. These three facets are interconnected and collectively determine the balance between tissue oxygenation and energy supply and demand. This article will elucidate commonly used monitoring methods and clinically valuable assessment models within this system, offering theoretical and technical guidance to deepen our understanding of the pathological processes of perioperative organ injury, enhance surgical safety and success rates, and improve patient prognosis and quality of life.

Development, quality, and influencing factors of colonoscopy in China: results from the national census in 2013 and 2020

Background and Aim

With the increasing burden of colorectal cancer (CRC), the practice of colonoscopy is gaining attention worldwide. However, it exhibits distinct trends between developing and developed countries. This study aims to explore its development and identify influencing factors in China.

Methods

The Chinese Digestive Endoscopy Censuses were conducted twice in mainland China under the supervision of health authorities. Information regarding the practice of colonoscopy was collected through a structured online questionnaire. The authenticity of the data was evaluated through logical tests, and a random selection of endoscopic reports underwent manual validation by Quality Control Centers. Potential factors associated with colonoscopy were analyzed using real-world information.

Results

From 2012 to 2019, the number of hospitals that performed colonoscopy increased from 3,210 to 6,325 (1.97-fold), and the volume increased from 5.83 to 12.92 million (2.21-fold). The utilization rate rose from 436.0 to 914.8 per 100,000 inhabitants (2.10-fold). However, there was an exacerbation of regional inequality in the adequacy of colonoscopy. Regions with higher incidence of CRC, higher gross domestic product per capita, more average numbers of endoscopists and tertiary hospitals tended to provide more accessible colonoscopy (P<0.001). Nationwide, the cecal intubation rate improved from 83.9% to 94.4% and the unadjusted adenoma detection rate (ADR) improved from 16.3% to 18.1%. Overall, hospital grading, educational background of endoscopists, economic income, and colonoscopy volume were observed as the significantly positive factors affecting ADR (P<0.05), but not the incidence of CRC or the number of endoscopists.

Conclusions

Tremendous progress in colonoscopy has been made in China, but some issues needed timely reflection. Our findings provide timely evidence for better colonoscopy strategies and measures, such as quality control and medical education of endoscopists.

[Considerations on pathological diagnosis of inherited metabolic liver disease]

A liver biopsy has an important suggestive role in the diagnosis of inherited metabolic liver disease (IMLD). This article introduces the IMLD pathological diagnosis considerations, five types of classification of liver biopsy based on the morphological characteristics (basic normal liver tissue morphology, steatosis, cholestatic disease, storage/deposition, and hepatitis), and a summary of the pathological characteristics of different injury patterns and common diseases in order to provide clues for the correct diagnosis.

[Histological regression and clinical benefits in patients with liver cirrhosis after long-term anti-HBV treatment]

Objective: Our study aims to determine histological regression and clinical improvement after long-term antiviral therapy in hepatitis B virus-related cirrhosis patients. Methods: Treatment-naïve chronic hepatitis B patients with histologically or clinically diagnosed liver cirrhosis were enrolled. Liver biopsies were performed after 5 years entecavir-based antiviral treatment. Patients were followed up every 6 months. Cirrhosis regression was evaluated based on Metavir system and P-I-R score. Clinical improvement was evaluated before and after the long-term treatment. Kruskal Wallis test and Wilcoxon signed-rank test were used for continuous variables, Fisher's exact test was used for categorical variables and multivariate analysis was performed using logistic regression analysis. Results: Totals of 73 patients with HBV-related liver cirrhosis were enrolled. Among them, 30 (41.1%) patients were biopsy proved liver cirrhosis and the remaining 43 (58.9%) cirrhotic patients were diagnosed by clinical features. Based on Metavir system and P-I-R score, 72.6% (53/73) patients attained histological regression. Furthermore, 30.1% (22/73) were defined as significant regression (Metavir decrease ≥2 stage), 42.5% (31/73) were mild regression (Metavir decrease 1 stage or predominantly regressive by P-I-R system if still cirrhosis after treatment) and 27.4% (20/73) were the non-regression. Compared to levels of clinical characteristics at baseline, HBV DNA, ALT, AST, liver stiffness(decreased from 12.7 to 6.4 kPa in significant regression, from 18.1 to 7.3 kPa in mild regression and from 21.4 to 11.2 kPa in non-regression)and Ishak-HAI score significantly decreased after 5 years of anti-HBV treatment, while serum levels of platelets and albumin improved remarkably (P<0.05). In multivariate analysis, only the pre-treatment liver stiffness level was associated with significant regression (OR=0.887, 95%CI: 0.802-0.981, P=0.020). Conclusions: After long-term antiviral therapy, patients with HBV-related cirrhosis are easily to attain improvements in clinical parameters, while a certain percentage of these patients still cannot achieve histological reversal.

[Campaigning the innovation and practice of anesthesia and perioperative management for elderly patients in China]

The aged population in China is rapidly increasing, but there is a relative lower anesthesia rate with surgical indication for elderly patients because of worry for higher morbidity and mortality. In past five years, Chinese anesthesiologists have made the tremendous efforts to change this situation in as follow aspects. Firstly, establishing the anesthesia and multidisciplinary evaluation system for elderly patients to improve preoperative functional status, and accelerating the postoperative rehabilitation process. Secondly, releasing the publications of perioperative experts consensus for elderly patients based on the high level clinical researches to highlight clinical practice in China. Thirdly, implementing online virtual MDT discussion of anesthesia and perioperative management for critical elderly patients to improve perioperative diagnosis and treatment level. Fourthly, making the innovation of clinical practice and management pathway to adopt to the ERAS' clinical requests for elderly patients, especially advanced aged patients.

[The low-dose opioids therapy of perioperative multi-mode analgesia is pivotal to the enhanced recovery after surgery for elderly patients]

The implementation of enhanced recovery after surgery in elderly patients should be under the premise of adequate perioperative analgesia/anti-stress. The aims of perioperative multimodal low-dose opioids analgesia therapy are reducing opioid-related adverse reactions and the impact on process of postoperative recovery.

Meishan neonatal piglets tend to have higher intestinal barrier function than crossbred neonatal piglets

Meishan pigs tend to have higher disease resistance than commercial breeds, although more studies are needed to confirm this difference. This study compared intestinal barrier function between Meishan and crossbred neonatal piglets to provide guidance for both the breeding and nutritional regulation of pigs. Six Meishan piglets and 6 Duroc × (Landrace × Yorkshire) crossbred neonatal piglets (all with normal birth weights) were obtained and allocated into the MEIS and CROSS groups, respectively. Intestinal morphology, goblet cell numbers, antioxidant enzyme activity, and cytokine gene and tight junction protein expression were assessed. The results showed that BW was lower in the MEIS group than in the CROSS group (P < 0.01). The relative lengths of the duodenum (P < 0.05), jejunum (P < 0.01) and ileum (P < 0.01) in the MEIS group were higher than those in the CROSS group. Compared with the CROSS group, the MEIS group exhibited shorter villus lengths in the duodenum and jejunum (P < 0.01), a shallower crypt depth in the ileum (P < 0.001) and denser and longer microvilli in the intestine. The numbers of GCs in the duodenum (P < 0.01) and jejunum (P < 0.001) and the activity levels of glutathione peroxidase (P < 0.05) in the jejunum and of catalase (P < 0.01) and superoxide dismutase (P < 0.01) in the ileum were higher in the MEIS group than in the CROSS group. Compared with the CROSS group, the MEIS group exhibited higher gene expression levels of interleukin (IL) 4 and interferon γ (IFNγ) in the jejunum (P < 0.05); IL2 (P < 0.05), IL4 (P < 0.01) and IFNγ (P < 0.001) in the ileum; and mucin 2 (P < 0.01) and occludin (P < 0.05) in the duodenum. In conclusion, Meishan neonatal piglets showed lower birth weights but higher intestinal barrier function than crossbred piglets.

[Qualitative pathological assessment of liver fibrosis regression after antiviral therapy in patients with chronic hepatitis B]

Objective: To investigate the methods for qualitative pathological assessment of dynamic changes in liver fibrosis/cirrhosis after antiviral therapy in patients with chronic hepatitis B (CHB), since antiviral therapy can partially reverse liver fibrosis and cirrhosis caused by hepatitis B and semi-quantitative, rather than qualitative, pathological assessment is often used for the research on liver fibrosis regression. Methods: Previously untreated CHB patients with liver fibrosis and cirrhosis were enrolled, and liver biopsy was performed before treatment and at 78 weeks after the antiviral therapy based on entecavir. The follow-up assessment was performed once every half a year. Based on the proportion of different types of fibrous septum, we put forward the new qualitative criteria called P-I-R classification (predominantly progressive, predominantly regressive, and indeterminate) for evaluating dynamic changes in liver fibrosis. This classification or Ishak fibrosis stage was used to evaluate the change in liver fibrosis after treatment and Ishak liver inflammation score was used to evaluate the change in liver inflammation after treatment. Results: A total of 112 CHB patients who underwent liver biopsy before and after treatment were enrolled, and among these patients, 71 with an Ishak stage of ≥3 and qualified results of live biopsy were included in the final analysis. Based on the P-I-R classification, 58% (41/71) were classified as predominantly progressive, 29% (21/71) were classified as indeterminate, and 13% (9/71) were classified as predominantly regressive; there were no significant differences between the three groups in alanine aminotransferase, aspartate aminotransferase, albumin, HBeAg positive rate, HBV DNA, and liver stiffness (P < 0.05). After treatment, the proportion of predominantly progressive, indeterminate, or predominantly regressive patients changed to 11% (8/71), 11% (8/71), and 78% (55/71), respectively. Among the 35 patients who had no change in Ishak stage after treatment, 72% (25/35) were classified as predominantly regressive and had certain reductions in the Laennec score, percentage of collagen area, and liver stiffness. Conclusion: This new P-I-R classification can be used to assess the dynamic changes in liver fibrosis after antiviral therapy in CHB patients.

[Continuous fascia iliaca compartment block combined with oral analgesics for pre-operative pain control in elderly hip fracture patients]

Objective: The purpose of this study was to assess the efficacy of ultrasound-guided continuous fascia iliaca compartment block combined with oral analgesics for pre-operative pain control in elderly patients with hip fracture. Methods: One hundred and sixteen patients with hip fractures in Xuan Wu Hospital of Capital Medical University during Dec. 2015 to Dec. 2016 were included. These patients were randomized into 2 groups: control group (group C) (receiving the traditional analgesia: tramadol 50 mg and paracetamol 500 mg tid, po from admission to surgery), study group (group S) (receiving ultrasound-guided continuous fascia iliaca compartment block combined with oral analgesics for pre-operative pain control from admission to surgery). Pain relief or pain intensity was assessed preoperatively at before administration of analgesia (T₀), 1 h after administration of analgesia (T₁), the second day after admission(T₂), in the morning of surgery day (before surgery) (T₃) using a visual analog scale. The satisfaction score with the analgesic regimen preoperatively was recorded. The amount of rescue analgesia, occurrence of adverse events (nausea, vomiting, respiratory depression, over sedation) and continuous fascia iliaca compartment block complications were also collected. Results: Pain scores (VAS) at passive movement of group S were significantly lower at T₁ (32±8), T₂ (32±8) and T₃ (34±7) than that at T₀ (73±12) (all P<0.05). VAS at rest of group S were significantly lower than those of group C at T₃ (t=3.488, P<0.05). VAS at passive movement of group S were significantly lower than those of group C at T_1,T_2,T₃ (P<0.05). The satisfaction score with the analgesic regimen was greater in group S (74±10) than that in group C (46±11) (t=-14.209, P<0.05). The incidence of rescue analgesia was lower in group S (0) than in group C (17.2%) (χ²=5.472, P<0.05). The occurrence of nausea and vomiting was 6.9% and 1.7% in group S, which were lower than that in group C (22.4%, 12.1%) (χ²=6.779, 2.416, all P<0.05). There were no obvious complications of continuous fascia iliaca compartment block in group S. Conclusion: Ultrasound guided continuous fascia iliaca compartment block combined with oral analgesics preoperatively is an effective way of providing analgesia for elderly with hip fracture, which can improve the patient's comfort and satisfaction.

[Expression and mechanism of nitric oxide synthase in cerebral hyperperfusion rats]

OBJECTIVE

To explore the expression and mechanism of different nitric oxide synthase in cerebral hyperperfusion rats.

METHODS

Male Wistar rats were anesthetized and a ventral midline incision was made. The bilateral common carotid arteries were gently separated. Each artery was ligated with a 5-0 silk suture. Sham groups underwent the same operation without occlusion two weeks later, the ligature was loosened under a microscope to induce reperfusion. Phenylephrine was administered at concentration of 50 μg/ml via tail vein.After hyperperfusion, the expression of iNOS and eNOS in hippocampus , cortex and common carotid arteries of rats brain was observed by using Western blot of each group.

RESULTS

The expression of iNOS in differernt sites were increased significantly after reperfusion of 24 hours. The ratio of iNOS and β-actin in hippocampus in sham, BCAO, HP, HP 24 and HP 48 groups were 21.10±2.53, 24.37±2.30, 28.34±2.86, 43.76±2.58, 38.90±3.17, respectively. There was significant difference between HP 24 and other groups (F=13.03, all P<0.05). The ratio of iNOS and β-actin in cortex in each group were 12.98±2.31, 15.00±1.66, 14.71±1.48, 34.76±5.01, 32.60±5.73, respectively (F=8.42, all P<0.05). The ratio of iNOS and β-actin in common carotid arteries in each group were 7.30±2.55, 8.83±1.45, 4.76±0.71, 28.00±2.21, 26.29±3.33 (F=24.82, all P<0.05). While the levels of eNOS in that three sites presented no significant change(all P>0.05).

CONCLUSIONS

Hyperperfusion can induce iNOS ecpression in quantities in hippocamps, cortex and common carotid arteries. These levesl would last until 48 hours after reperfusion. This process suggests that iNOS is the possible mechanism of hyperperfusion.

Transcutaneous electrical nerve stimulation on acupoints reduces fentanyl requirement for postoperative pain relief after total hip arthroplasty in elderly patients

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is regarded as an effective treatment for various types of pain. However, no randomized controlled trial has investigated TENS on acupoints for postoperative analgesia in elderly patients. This study aim to investigate whether TENS on acupoints has any favorable effect on complementary analgesia after total hip arthroplasty (THA) for elderly patients compared with a sham control treatment.

METHODS

Sixty-eight elderly patients requiring THA surgery were enrolled and randomly allocated to one of two groups. Group Acu received true TENS on acupoints (bilateral P6, L14; ST36, GB31 ipsilateral to the surgery site) and Group Sham received sham treatment. All patients received patient-controlled analgesia for two days postoperatively. Analgesia was assessed by postoperative fentanyl requirement and pain intensity using a visual analogue scale (VAS-10 cm). The incidence of analgesia-related side effects, optional medication use and effects of patients' blinding were recorded.

RESULTS

Fentanyl consumption in Group Acu was lower than that in Group Sham at 24 h (mean ± SD; 360±117 vs. 572±132 μg; P<0.001) and 48 h (712±184 vs. 1022±197 μg; P<0.001) after surgery. Postoperative pain intensity measured by VAS was similar in both groups. The incidence of opioid-related side effects and rescue medication for postoperative analgesia was significantly higher in Group Sham than in Group Acu. Differences between the groups regarding the effects of patients' blinding were not significant.

CONCLUSION

TENS on specific acupoints is an effective and complementary approach to reduce postoperative analgesic requirement in elderly patients after THA.

Inhibition effect of poly(γ-glutamic acid) on lead-induced toxicity in mice

The objectives of this study were to evaluate the efficiency in treatment of lead-induced intoxication in mice with γ-PGA as chelating agent and compare with the drug (meso-2,3-dimercaptosuccinic acid). The results showed the incorporation of γ-PGA at 200 and 400 mg/kg could reduce the accumulation of lead in the liver, heart, and testis; however, the latter was more effective in decreasing the lead content in the kidney and spleen. Nevertheless, both doses failed to inhibit the lead accumulation in the lung and brain. Additionally, both doses of γ-PGA could reduce TBARs in the kidney and brain, as well as elevate δ-aminolevulinic acid dehydrase (δ-ALAD) activity in blood and decrease glutamic pyruvic transaminase (GPT) and lactic dehydrogenase (LDH) activities in the serum. For hematological parameters, both white blood cells (WBCs) and hematocrite (HCT) were raised by 400 mg/kg of γ-PGA, while for both doses of γ-PGA, a slight decline in hemoglobin (HGB), mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC) was observed, with the red blood cells (RBCs) being unaffected.

Proposed thermodynamic method to predict the glass formation of the ternary transition metal systems

By considering the energetic competition between the crystalline solid solution and glass phase, a thermodynamic method is proposed to predict/determine the glass forming range of a ternary metal system and in terms of the dynamics, the parameter gamma(ABC)* is further defined to search for a proper alloy with superior glass forming ability in the system. 10 more ternary/binary metal systems, e.g. the Cu-Zr-Ti and Cu-Hf-Ti systems, were studied and the predicted alloys of superior glass forming ability match well with those reported from experimental observations.

Gabapentin toxicity: an important cause of altered consciousness in patients with uraemia

Gabapentin toxicity should be considered one of the differential diagnoses of altered consciousness in patients with compromised renal function, even after a single dose. We report a 57-year-old woman with diabetes mellitus and uraemia on regular haemodialysis who developed severe dizziness and lethargy after a single recommended dose of gabapentin for bilateral leg dysthesia. Because of progressive drowsiness and decreasing level of consciousness, one session of haemodialysis was performed and clinical recovery was dramatic. The adverse effects of gabapentin seem to vary from person to person and should be viewed with a high degree of suspicion, especially in patients taking this drug at the beginning.

Role of proximal gastric acid reflux in causation of respiratory symptoms in children with gastroesophageal reflux

OBJECTIVES

The association of gastroesophageal reflux (GER) and respiratory disorders is well known but the mechanism is still unclear. This study aims to evaluate the presence and severity of proximal gastric acid reflux in children having GER with or without respiratory symptoms.

METHODS

24 hour esophageal pH monitoring with a dual pH probe placed in the proximal and distal esophagus was performed in 23 and 31 children having GER with or without respiratory symptoms, respectively.

RESULTS

No significant difference in the parameters of pH monitoring in either proximal or distal esophagus was observed between GER patients with or without respiratory symptoms. The proportion of patients having proximal GER among those with respiratory symptoms was not significantly different from those without respiratory symptoms (P > 0.05).

CONCLUSION

Proximal esophageal acid reflux does not seem to play a role in the development of persistent respiratory symptoms in children with GER. Distal esophageal acid reflux is the predominant form of reflux in children with GER regardless of the occurrence of respiratory symptoms.

Observations of distinct atomic packings in Cu-Nb metallic glasses synthesized by ion beam mixing

The structural transformation and disordered atomic packing of metallic glasses in a selected immiscible system at equilibrium, i.e. the Cu-Nb system characterized by a positive heat of formation, are studied using ion beam mixing far from equilibrium. The experimental results indicate that the Cu-Nb metallic glasses could be formed in a composition range from 30 to 85 at.% of Nb and that the Cu-Nb metallic glasses are formed through two different structural phase transition routes, i.e. from the Nb-based body centred cubic and face centred cubic solid solutions, in which the two distinct predominant atomic packings have icosahedral and icositetrahedral orderings, respectively, revealed by the respective diffraction patterns. These observations not only help in formulating a general atomic structural spectrum for the binary metallic glasses, but also suggest an important concept of structural heredity: that the crystalline structure of the constituent metals plays a decisive role in determining the atomic structure of the resultant metallic glasses.

Preconsultation use of analgesics on adults presenting to the emergency department with acute appendicitis

OBJECTIVE

279 cases of appendicitis were reviewed and compared for the difference between those patients who received pain medication before consulting a surgeon and those who were not treated with analgesics.

METHODS

All patients aged 15 years and older who underwent appendicectomy for appendicitis between 1 July 2001 and 30 June 2002 were divided into group 1 (those who received preconsultaion use of analgesics) and group 2 (those who were not treated with analgesics). The following measures were compared: age, sex, symptom duration, initial vital signs, white blood cell counts, frequency of imaging studies, time to operative intervention, and operative findings. Continuous and categorical variables were analysed using t and chi(2) tests, respectively.

RESULTS

A total of 279 patients were included for analysis. Patient details (age, sex, symptom duration) of the two study groups were similar. There was no statistically significant difference between group 1 and group 2 with respect to vital signs (systolic blood pressure, pulse rate, respiratory rate, body temperature), white blood cell counts, and frequency of imaging studies (ultrasound, computed tomography). There was no significant difference in the rate of perforated appendicitis between the two study groups although a shorter median time to operative intervention has been found in the group who received analegesia.

CONCLUSION

The preconsultation use of analgesics in ED patients with a final diagnosis of appendicitis is not associated with a longer delay to operative intervention and is not associated with an increased rate of perforated appendicitis.

Mutant alleles at the rugosus loci in pea affect seed moisture sorption isotherms and the relations between seed longevity and moisture content

Pea (Pisum sativum L.) mutant near-isogenic lines (RRrbrb, rrRbRb, rrrbrb) with lower starch but higher lipid contents, brought about by lesions in the starch biosynthetic pathway, had seed moisture sorption isotherms displaced below that of the wild type (RRRbRb). The negative logarithmic relationship between seed longevity and seed storage moisture content (%, f.wt basis), determined in hermetic storage at 65 degrees C, also differed: longevity in the mutant near-isogenic lines was poorer and less sensitive to moisture content than in the wild type (i.e. C(W) was lower). The low-moisture-content limit (m(c)) to this relation also differed, being lower in the mutant near-isogenic lines (5.4-5.9%) than in the wild type (6.1%). In contrast, all four near-isogenic lines showed no difference (P >0.25) in the negative semi-logarithmic relationship between equilibrium relative humidity (ERH) and seed longevity. It is concluded that the effect of these alleles at the r and rb loci on seed longevity was largely indirect; a consequence of their effect on seed composition and hence on moisture sorption isotherms. However, this explanation could not be invoked at moisture contents below m(c) where differences in longevity remained substantial (RRRbRb double that of rrrbrb). Hence, these mutant alleles affected seed longevity directly at very low moisture contents.

Mutant alleles at the rugosus loci in pea affect seed moisture sorption isotherms and the relations between seed longevity and moisture content

Pea (Pisum sativum L.) mutant near-isogenic lines (RRrbrb, rrRbRb, rrrbrb) with lower starch but higher lipid contents, brought about by lesions in the starch biosynthetic pathway, had seed moisture sorption isotherms displaced below that of the wild type (RRRbRb). The negative logarithmic relationship between seed longevity and seed storage moisture content (%, f.wt basis), determined in hermetic storage at 65 degrees C, also differed: longevity in the mutant near-isogenic lines was poorer and less sensitive to moisture content than in the wild type (i.e. C(W) was lower). The low-moisture-content limit (m(c)) to this relation also differed, being lower in the mutant near-isogenic lines (5.4-5.9%) than in the wild type (6.1%). In contrast, all four near-isogenic lines showed no difference (P >0.25) in the negative semi-logarithmic relationship between equilibrium relative humidity (ERH) and seed longevity. It is concluded that the effect of these alleles at the r and rb loci on seed longevity was largely indirect; a consequence of their effect on seed composition and hence on moisture sorption isotherms. However, this explanation could not be invoked at moisture contents below m(c) where differences in longevity remained substantial (RRRbRb double that of rrrbrb). Hence, these mutant alleles affected seed longevity directly at very low moisture contents.

Structural studies of starches with different water contents

The proportion of double helices in starches from a series of pea [rb, rug4-b, rug3-a, and lam-c mutants, and the wild type (WT) parental line], potato and maize (normal and low amylose), and wheat (normal) lines, ranged from about 30-50% on a dry weight basis. In relatively dry starch powders, only about half of the double helices were in crystalline order, this proportion being higher for A-type than for B-type starches. Using starch from WT pea as an example, it was found that increasing water content results in an increase in total crystallinity. When the water content was raised to a level similar to that in excess water, the proportion of crystallinity was close to the proportion of double helices (DH). Measuring crystallinity in starches with a high water content is difficult using traditional methods such as x-ray diffraction. A method was developed, therefore, for determining starch structural characteristics in excess water by measuring the enthalpy of gelatinization transition in quasi-equilibrium differential scanning calorimetry (DSC) experiments. It is suggested that DH% = DeltaH(sp)/DeltaH(DH) x 100%, where DeltaH(sp) and DeltaH(DH) represent the specific enthalpies of gelatinisation transition, DeltaH(sp) being measured as J/g dry starch weight and DeltaH(DH) as J/g DH, in starch. Studies on potato and maize starches in excess water and in 0.6M KCl showed, respectively, that DeltaH(DH) was 36.3 and 35.6 J/g for B-type polymorphs and 33.0 and 35.0 J/g for A-type polymorphs. For C-type starches, such as those from pea, intermediate values of DeltaH(DH), related to the proportions A-/B-polymorphs, should be used. The type of crystallinity in starch can be determined by the shift in peak temperature for thermograms in excess water and in excess 0.6M KCl. For B-polymorphs this shift was found to be approximately 2-3 degrees C and for A-polymorphs approximately 7-12 degrees C. The ratio between ordered areas with both A- and B-polymorphs can be determined from the enthalpies of disruption of each area. These enthalpies can be obtained by deconvolution of bimodal thermograms produced by C-type starches in excess 0.6M KCl. This methodical approach can be applied to all starches that give a sharp gelatinisation thermogram in excess water. Using a range of methods, including DSC, it was found that starch granules from the mutant peas are constructed in a similar way to those from the WT, with B-polymorphs in the centre and A-polymorphs at the periphery of all granules. The proportion of A/B-polymorphs, however, differed between the mutants. It was found that in addition to increasing the total crystallinity, increasing the water content within the granules also resulted in an increase in the proportion of B-polymorphs.

Kinetics of iron release from pig spleen ferritin with bare platinum electrode reduction

Several anaerobic electrochemical cells were employed to study the kinetics of iron release from pig spleen ferritin (PSF) at a bare platinum electrode. Controlled potential microcoulometry (CPM) is the principal technology used to investigate the kinetics in the absence of a mediator. A kinetic study of iron release by microcoulometry has revealed that ferritin undergoes direct electron transfer at the electrode in the absence of a mediator, indicating that ferritin is an electroactive protein. Several experiments failed to show that alpha'alpha-bipyridyl has the capacity to reduce hydrolyzed Fe(3+) within the ferritin core after it has been reduced by the electrode at -600 mV vs. NHE in the absence of mediator. PSF is known to bind heme to generate a hemeoprotein, named pig spleen hemeoferritin (PSF(ho)). The rate of iron release is accelerated by the heme binding to PSF(ho) without the need for small mediators. Under similar conditions, two kinetic processes for iron release from PSF and bacterial ferritin of Azoaobacter vinelandii (AvBF) were studied and both fit a zero-order law. In addition, the rate of iron release in PSF can be accelerated two-fold by a specific reduction system consisting of ascorbic acid (AA) and the bare platinum electrode at -600 mV. However, this kinetic process does not follow zero-, half-, first, or second-order rate laws. A model is proposed to explain a mechanism of direct electron transfer between ferritin and the electrode is derived to describe the kinetics of iron release.

Multiple, distinct isoforms of sucrose synthase in pea

Genes encoding three isoforms of sucrose synthase (Sus1, Sus2, and Sus3) have been cloned from pea (Pisum sativum). The genes have distinct patterns of expression in different organs of the plant, and during organ development. Studies of the isoforms expressed as recombinant proteins in Escherichia coli show that they differ in kinetic properties. Although not of great magnitude, the differences in properties are consistent with some differentiation of physiological function between the isoforms. Evidence for differentiation of function in vivo comes from the phenotypes of rug4 mutants of pea, which carry mutations in the gene encoding Sus1. One mutant line (rug4-c) lacks detectable Sus1 protein in both the soluble and membrane-associated fractions of the embryo, and Sus activity in the embryo is reduced by 95%. The starch content of the embryo is reduced by 30%, but the cellulose content is unaffected. The results imply that different isoforms of Sus may channel carbon from sucrose towards different metabolic fates within the cell.

Multiple, distinct isoforms of sucrose synthase in pea

Genes encoding three isoforms of sucrose synthase (Sus1, Sus2, and Sus3) have been cloned from pea (Pisum sativum). The genes have distinct patterns of expression in different organs of the plant, and during organ development. Studies of the isoforms expressed as recombinant proteins in Escherichia coli show that they differ in kinetic properties. Although not of great magnitude, the differences in properties are consistent with some differentiation of physiological function between the isoforms. Evidence for differentiation of function in vivo comes from the phenotypes of rug4 mutants of pea, which carry mutations in the gene encoding Sus1. One mutant line (rug4-c) lacks detectable Sus1 protein in both the soluble and membrane-associated fractions of the embryo, and Sus activity in the embryo is reduced by 95%. The starch content of the embryo is reduced by 30%, but the cellulose content is unaffected. The results imply that different isoforms of Sus may channel carbon from sucrose towards different metabolic fates within the cell.

Intravenous morphine reduces plasma endothelin 1 concentration through activation of neutral endopeptidase 24.11 in patients with myocardial infarction

STUDY OBJECTIVE

Morphine has multiple cardiovascular effects, but its action on hydrolysis of endothelin 1 (ET-1) has not been investigated.

METHODS

We measured plasma levels of ET-1, C-terminal degradation products of ET-1, and neutral endopeptidase 24.11 (NEP) in 68 patients with acute Q-wave myocardial infarction and 29 control subjects. All the patients underwent blood sampling at initial presentation and 10 minutes later. Thirty-six of those with Q-wave myocardial infarction intravenously received 3 mg of morphine immediately after the first sampling (group 1), and the other 32 received the same after the second sampling (group 2). Twenty-four of the control subjects (group 3) were randomized to the protocol of group 1, and the remaining 5 subjects (group 4) were randomized to the protocol of group 2.

RESULTS

The plasma ET-1 levels were significantly higher in groups 1 and 2 than in groups 3 and 4 (control groups). In group 1, the ET-1 level decreased significantly at second blood samplings (2.5+/-0.4 pmol/L versus 1.7+/-0.6 pmol/L, P <.001), whereas there were no definite changes of ET-1 levels in group 2 (2.5+/-0.5 pmol/L versus 2.6+/-0.6 pmol/L, P =not significant). However, the C-terminal degradation products increased significantly at second blood samplings in group 1 (0.8+/-0.2 pmol/L versus 1.3+/-0.4 pmol/L, P <.001), whereas there were no definite changes in group 2 (0.9+/-0.3 pmol/L versus 0.9+/-0.4 pmol/L, P =not significant). There was no significant difference in baseline NEP activities between groups 1 and 2 (5.02+/-1.30 nmol/mg protein versus 5.06+/-1.48 nmol/mg protein, P =not significant). However, the NEP activities at second blood samplings declined significantly in group 1 (9.76+/-1.76 nmol/mg protein, P <.001 versus baseline), whereas no definite changes were observed in group 2 (5.09+/-1.62 nmol/mg protein, P =not significant versus baseline).

CONCLUSION

Intravenous morphine may increase NEP activities to accentuate hydrolysis of ET-1.

Top-down morphogenesis of colorectal tumors

One of the fundamental tenets of oncology is that tumors arise from stem cells. In the colon, stem cells are thought to reside at the base of crypts. In the early stages of tumorigenesis, however, dysplastic cells are routinely found at the luminal surface of the crypts whereas the cells at the bases of these same crypts appear morphologically normal. To understand this discrepancy, we evaluated the molecular characteristics of cells isolated from the bases and orifices of the same crypts in small colorectal adenomas. We found that the dysplastic cells at the tops of the crypts often exhibited genetic alterations of adenomatous polyposis coli (APC) and neoplasia-associated patterns of gene expression. In contrast, cells located at the base of these same crypts did not contain such alterations and were not clonally related to the contiguous transformed cells above them. These results imply that development of adenomatous polyps proceeds through a top-down mechanism. Genetically altered cells in the superficial portions of the mucosae spread laterally and downward to form new crypts that first connect to preexisting normal crypts and eventually replace them.

Recombinant DNA vaccines protect against tumors that are resistant to recombinant vaccinia vaccines containing the same gene

Antigen-specific cancer immunotherapy involves the delivery of tumor-associated antigen to the host for the generation of tumor-specific immune responses and antitumor effects. We hypothesized that different delivery systems may influence the pattern of antigen-specific immune response and the outcome of antitumor effect. We therefore evaluated recombinant vaccinia virus and naked DNA for the generation of antigen-specific immune responses and antitumor effects. We previously found that recombinant vaccinia and naked DNA vaccines containing the chimeric Sig/E7/LAMP-1 gene were capable of controlling the growth of HPV-16 E7-expressing tumor cells (TC-1). In this study, we performed a head-to-head comparison of optimized delivery of Sig/E7/LAMP-1 vaccinia and DNA vaccines using dose-escalating tumor challenge. At a dose of 1 x 10(6) TC-1 cells per mouse, Sig/E7/LAMP-1 DNA provided 100% protection against subcutaneous growth of tumors, while Vac-Sig/E7/LAMP-1 protected only 40% of the mice. Furthermore, Sig/E7/LAMP-1 DNA vaccines are capable of protecting against challenge with a more stringent subclone of TC-1 (TC-1 P2) established from TC-1 tumors that survived initial Sig/E7/LAMP-1 vaccinia vaccination. Immunological assays revealed that both vaccines induced comparable levels of CD8(+) T cell precursors and anti-E7 antibody titers. Interestingly, Sig/E7/LAMP-1 vaccinia induced both E7-specific IFN-gamma- and IL4-secreting CD4(+) T cell precursors while Sig/E7/LAMP-1 DNA induced only E7-specific IFN-gamma-secreting CD4(+) T cell precursors. We also found that IL-4 knockout C57BL/6 mice vaccinated with Sig/E7/LAMP-1 vaccinia exhibited a more potent antitumor effect than vaccinated wild-type C57BL/6 mice in our tumor protection experiments. These results suggest that IL-4 may play a detrimental role in the antitumor effect mediated by vaccinia vaccines. Our findings suggested that DNA vaccines may provide better tumor protection than vaccinia vaccines employing the same gene, which may have implications in the future design of antigen-specific cancer immunotherapy.

Antigen-specific cancer immunotherapy using a GM-CSF secreting allogeneic tumor cell-based vaccine

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-transduced autologous tumor cell-based vaccines are currently one of the major forms of cancer vaccines. However, the preparation of GM-CSF-transduced autologous tumor vaccines is time-consuming and technically challenging. In addition, the host antigen presenting cells, rather than the tumor vaccine cells themselves, present tumor-specific antigens and prime the host T cells. Therefore, we tested the efficacy of antigen-specific allogeneic tumor vaccines. We used human papillomavirus 16 (HPV-16) E7 protein as a model tumor antigen, which is associated with the development of most cervical carcinoma. B16, a C57BL/6 (H-2(b)) derived melanoma cell line, was genetically engineered to produce GM-CSF alone (B16GM), HPV-16 E7 alone (B16E7), or both (B16GME7). These vaccine cells were injected into BALB/c (H-2(d)) mice (10(6) cells/mouse). Two weeks later, mice were challenged with 10(5) live HPV-16 E7(+) BL-1 (H-2(d)) tumor cells and monitored for tumor progression twice weekly. To determine the effective cell population in the antitumor immunity elicited by B16GME7, we carried out in vivo antibody depletion experiments using CD4 and CD8 specific antibodies. In addition, as a measure of the immune responses produced by B16GME7, we performed an in vitro cytotoxic T lymphocyte assay using a standard chromium release method. We found that all of the mice vaccinated with B16GME7 remained tumor free 49 days post-BL-1 challenge. In contrast, mice vaccinated with B16GM and B16E7 did not show any tumor protection against a similar dose of BL-1 cells. Furthermore, the antitumor immunity produced by B16GME7 was dependent on both CD4 and CD8 T cells. In addition, E7-specific cytotoxic T lymphocyte activity could be readily demonstrated in mice immunized with B16GME7. These results suggest that allogeneic tumor cells transduced with GM-CSF and the tumor antigen, HPV-16 E7, cannot only generate an E7-specific cytotoxic T lymphocytes response in vitro, but can also elicit a potent antitumor immune response against an E7 expressing tumor in vivo.

Human mu-opioid receptor overexpressed in Sf9 insect cells functionally coupled to endogenous Gi/o proteins

Human mu-opioid receptor (HmuOR) with a tag of six consecutive histidines at its carboxyl terminus had been expressed in recombinant baculovirus infected Sf9 insect cells. The maximal binding capacity for the [3H] diprenorphine and [3H]ohmefentanyl (Ohm) were 9.1 +/- 0.7 and 6.52 +/- 0.23 nmol/g protein, respectively. The [3H] diprenorphine or [3H] Ohm binding to the receptor expressed in Sf9 cells was strongly inhibited by mu-selective agonists [D-Ala2, N-methyl-Phe4, glyol5]enkephalin (DAGO), Ohm, and morphine, but neither by delta nor by kappa selective agonist. Na+ (100 mM) and GTP (50 microM) could reduce HmuOR agonists etorphine and Ohm affinity binding to the overexpressed HmuOR. mu-selective agonists DAGO and Ohm effectively stimulated [35S]GTP-gammaS binding (EC50 = 2.7 nM and 6.9 nM) and inhibited forskolin- stimulated cAMP accumulation (IC50 = 0.9 nM and 0.3 nM). The agonist-dependent effects could be blocked by opioid antagonist naloxone or by pretreatment of cells with pertussis toxin (PTX). These results demonstrated that HmuOR overexpressed in Sf9 insect cells functionally coupled to endogenous G(i/o) proteins.

Intramuscular administration of E7-transfected dendritic cells generates the most potent E7-specific anti-tumor immunity

Dendritic cells (DCs) are highly efficient antigen-presenting cells capable of priming both cytotoxic and helper T cells in vivo. Recent studies have demonstrated the potential use of DCs that are modified to carry tumor-specific antigens in cancer vaccines. However, the optimal administration route of DC-based vaccines to generate the greatest anti-tumor effect remains to be determined. This study is aimed at comparing the levels of immune responses and anti-tumor effect generated through different administration routes of DC-based vaccination. We chose the E7 gene product of human papillomavirus (HPV) as the model antigen and generated a stable DC line (designated as DC-E7) that constitutively expresses the E7 gene. Among the three different routes of DC-E7 vaccine administration in a murine model, we found that intramuscular administration generated the greatest anti-tumor immunity compared with subcutaneous and intravenous routes of administration. Furthermore, intramuscular administration of DC-E7 elicited the highest levels of E7-specific antibody and greatest numbers of E7-specific CD4+ T helper and CD8+ T cell precursors. Our results indicate that the potency of DC-based vaccines depends on the specific route of administration and that intramuscular administration of E7-transfected DCs generates the most potent E7-specific anti-tumor immunity.

Boosting with recombinant vaccinia increases HPV-16 E7-specific T cell precursor frequencies of HPV-16 E7-expressing DNA vaccines

We have previously linked the sorting signals of the lysosome-associated membrane protein-1 (LAMP-1) to HPV-16 E7 antigen, creating a chimera, Sig/E7/LAMP-1. We found that both Sig/E7/LAMP-1-containing recombinant vaccinia virus (Vac-Sig/E7/LAMP-1) and Sig/E7/LAMP-1 DNA can generate strong antitumor immunity. To determine whether combination of Sig/E7/LAMP-1 DNA and Vac-Sig/E7/LAMP-1 can further enhance immune responses, sequential vaccination with Sig/E7/LAMP-1 DNA and Vac-Sig/E7/LAMP-1 was given. We found that priming with Sig/E7/LAMP-1 DNA and boosting with Vac-Sig/E7/LAMP-1 generated the strongest E7-specific CD8(+) T cell responses. Our results encourage the use of the DNA prime/vaccinia booster regimen in future clinical trials.

The rug3 locus of pea encodes plastidial phosphoglucomutase

Two cDNA clones were isolated from pea (Pisum sativum L.) and their deduced amino acid sequences shown to have significant homology to phosphoglucomutases from eukaryotic and prokaryotic sources. The longer cDNA contained a putative transit-peptide-encoding sequence, supporting the hypothesis that the isolated clones represent the cytosolic and plastidial isoforms of phosphoglucomutase in pea. Plastid protein import assays confirmed that the putative plastidial isoform was targeted to the plastid stroma where it was proteolytically processed. Expression, co-segregation, linkage, and molecular analyses have confirmed that the rug3 locus of pea encodes plastidial phosphoglucomutase. Mutations at this locus result in a near-starchless phenotype of the plant.

Enhancement of DNA vaccine potency by linkage of antigen gene to an HSP70 gene

Nucleic acid vaccines represent an attractive approach to generating antigen-specific immunity because of their stability and simplicity of delivery. However, there is still a need to increase the potency of DNA vaccines. Using human papillomavirus type 16 E7 as a model antigen, we evaluated the effect of linkage to Mycobacterium tuberculosis heat shock protein 70 (HSP70) on the potency of antigen-specific immunity generated by naked DNA vaccines. We found that vaccines containing E7-HSP70 fusion genes increased the frequency of E7-specific CD8+ T cells by at least 30-fold relative to vaccines containing the wild-type E7 gene. More importantly, this fusion converted a less effective vaccine into one with significant potency against established E7-expressing tumors. Surprisingly, E7-HSP70 fusion vaccines exclusively targeted CD8+ T cells; immunological and antitumor effects were completely CD4-independent. These results indicate that fusion of HSP70 to an antigen gene may greatly enhance the potency of DNA vaccines via CD8-dependent pathways.

Regulation of connexin 43 gene expression by cyclical mechanical stretch in neonatal rat cardiomyocytes

Myocardial cells respond to changes in the mechanical forces imposed on them with changes in myocardial tension in the short term and with structural remodeling in the long term. Since these responses involve intercellular communication, we have investigated regulation of the gap junction proteins, connexin 43 (Cx43), connexin 40 (Cx40) and connexin 37 (Cx37), by cyclical mechanical stretch. Results were compared with parallel experiments on c-fos and GAPDH. Twenty percent stretch of cultured rat cardiomyocytes caused a 3-fold increase in Cx43 mRNA levels by 2 h. c-fos mRNA levels increased after 30 min of stretch, whereas Cx40, Cx37, and GADPH mRNA did not change. Protein levels of Cx43 increased by 4 h and remained elevated for 16 h. New protein synthesis was not a requirement for the stretch-induced rise in Cx43 expression, since mRNA levels were unaffected by treatment with cycloheximide. In addition, mechanical stretch induced alkalization of cardiomyocytes that was antagonized by inhibiting Na-H exchanger (NHE). Gap junction potential (Gj) was concomitantly elevated. Chemical closure of Cx channels by insulin was followed by inhibition of NHE. In conclusion, cyclical mechanical stretch caused increased expression of the gap junction protein Cx43 in cardiomyocytes and also the Gj. The augmentation of Cx43 mRNA expression and its functional status were associated with activation of NHE.

Targeting human papillomavirus type 16 E7 to the endosomal/lysosomal compartment enhances the antitumor immunity of DNA vaccines against murine human papillomavirus type 16 E7-expressing tumors

DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.

Localization of type I inositol 1,4,5-triphosphate receptor in the outer segments of mammalian cones

Calcium enters the outer segment of a vertebrate photoreceptor through a cGMP-gated channel and is extruded via a Na/Ca, K exchanger. We have identified another element in mammalian cones that might help to control cytoplasmic calcium. Reverse transcription-PCR performed on isolated photoreceptors identified mRNA for the SII- splice variant of the type I receptor for inositol 1,4,5-triphosphate (IP3), and Western blots showed that the protein also is expressed in outer segments. Immunocytochemistry showed type I IP3 receptor to be abundant in red-sensitive and green-sensitive cones of the trichromatic monkey retina, but it was negative or weakly expressed in blue-sensitive cones and rods. Similarly, the green-sensitive cones expressed the receptor in dichromatic retina (cat, rabbit, and rat), but the blue-sensitive cones did not. Immunostain was localized to disk and plasma membranes on the cytoplasmic face. To restore sensitivity after a light flash, cytoplasmic cGMP must rise to its basal level, and this requires cytoplasmic calcium to fall. Cessation of calcium release via the IP3 receptor might accelerate this fall and thus explain why the cone recovers much faster than the rod. Furthermore, because its own activity of the IP3 receptor depends partly on cytoplasmic calcium, the receptor might control the set point of cytoplasmic calcium and thus affect cone sensitivity.

Alteration in transcripting the gene encoding the delta-opioid receptor in rat brain is not underlying the development of tolerance to [D-Ala2,D-Leu5] enkephalin

Previous study has demonstrated that chronic treatment of [D-Ala2,D-Leu5] enkephalin (DADLE) induces profound down-regulation of delta opioid receptor in rat brain. We further examined whether this down-regulation of receptor was due to a decrease in the transcription of gene encoding delta-opioid receptor (DOR-1). Rats received daily i.c.v. injection of DADLE for 1, 3, or 5 days and developed significant tolerance to the antinociceptive effect of DADLE after one-day treatment. We measured the level of mRNA in rat brain tissues using in situ hybridization. No significant changes in the mRNA levels of the cortex, striatum, hippocampus, and thalamus on any examined days were found as compared to those of rats received sham operation only. There is only a transient decrease of DOR-1 mRNA level in midbrain region that occurred after a three-day treatment. Thus, the result of this study did not suggest that alteration in transcription of gene-encoding delta-opioid receptor was responsible for the down-regulation of delta-opioid receptor associated with the development of tolerance to DADLE.

Morphine preconditioning attenuates neutrophil activation in rat models of myocardial infarction

Previous results from our laboratory have suggested that morphine can attenuate neutrophil activation in patients with acute myocardial infarction. To elucidate if morphine preconditioning (PC) has the same effects via activation of neutrophil endopeptidase 24.11 (NEP), we measured serum levels of intercellular adhesion molecule-1 (ICAM-1), gp100MEL14 and NEP in adult Wistar rats subjected to ten different protocols (n = 10 for each) at baseline, immediately after and 2 h after morphine PC. All groups were subjected to 30 min of occlusion and 2 h of reperfusion. Similarly, morphine-induced PC was elicited by 3-min drug infusions (100 micrograms/kg) interspersed with 5-min drug-free periods before the prolonged 30-min occlusion. Infarct size (IS), as a percentage of the area at risk (AAR), was determined by triphenyltetrazolium staining. Pretreatment with morphine increased NEP activities (9.86 +/- 1.98 vs. 5.12 +/- 1.10 nmol/mg protein in control group; p < 0.001). Naloxone (mu-opioid receptor antagonist) (4.82 +/- 1.02 nmol/mg protein) and phosphoramidon (NEP inhibitor) (4.66 +/- 1.00 nmol/mg protein) inhibited morphine-activated NEP, whereas glibenclamide (ATP-sensitive potassium channel antagonist) and chelerythrine (protein kinase C inhibitor) had no effects. The ICAM-1 and gp100MEL14 of the third sampling were lowest for those with morphine PC (280 +/- 30 ng/ml and 2.2 +/- 0.7 micrograms/ml; p < 0.001), but naloxone (372 +/- 38 ng/ml and 3.8 +/- 0.9 micrograms/ml) and phosphoramidon (382 +/- 40 ng/ml and 4.2 +/- 1.1 micrograms/ml) abolished the above phenomenon. IS/AAR were definitely lowest for those with morphine PC (24 +/- 7%; p < 0.05). Morphine preconditioning increases NEP activities to attenuate shedding of gp100MEL14 and to ICAM-1 and, thus, provides myocardial protection.

Neurochemistry of the mammalian cone 'synaptic complex'

The cone 'synaptic complex' is a unique structure in which a single presynaptic axon secretes glutamate onto processes of bipolar cells (both ON and OFF) and horizontal cells. In turn, the horizontal cell processes antagonize cone and bipolar responses to glutamate (probably by GABA). What still remains largely unknown is the molecular identity of the postsynaptic receptors and their exact locations. We identified several subunits of the glutamate receptor and the GABAA receptor expressed at the cone synaptic complex and localized them ultrastructurally. Glutamate receptors: (i) Invaginating (probably ON) bipolar dendrites in the monkey and rat express the metabotropic glutamate receptor, mGluR6. The stain is intense on the dendritic membrane where it first enters the invagination, and weak at the tip nearest to the ribbon. The cone membrane is electron-dense where it apposes the intense stain for mGluR6. Surprisingly, invaginating bipolar dendrites in the cat also express the AMPA receptor subunits, GluR2/3 and GluR4. (ii) Dendrites forming basal contacts in the cat (probably OFF) express the AMPA subunits GluR2/3, GluR4, and also the kainate subunit, GluR6/7. The stain is especially intense at the dendritic tips in apposition to electron-dense regions of cone membrane. (iii) Horizontal cells in the cat express the AMPA subunits GluR2/3, GluR4 and the kainate subunit, GluR6/7. The stain is strongest in the cytosol of somas and primary dendrites, but is also present in the invaginating terminals where it localizes to the membrane subjacent to the ribbon. GABAA receptors: (i) ON and OFF bipolar dendrites in the monkey express the alpha 1 and beta 2/3 subunits. The stain is localized to the bipolar cell membrane in apposition to horizontal cell processes. (ii) Cones did not express the GABAA subunits tested by immunocytochemistry, but beta 3 mRNA was amplified by RT-PCR from rat photoreceptors.

CONCLUSIONS

(i) mGluR6 receptors concentrate on dendrites at the base of the invagination rather than at the apex. This implies that receptors at both 'invaginating' and 'basal' contacts lie roughly equidistant from the release sites and should therefore receive similar spatiotemporal concentrations of glutamate. (ii) The 'cone' membrane is electron-dense opposite to the receptor sites on both ON and OFF bipolar cells. This suggests a special role for this region in synaptic transmission. Possibly, these densities signify a transporter that would regulate glutamate concentration at sites remote (> 200 nm) from the locus of vesicle release.