Chinese Preclinical Alzheimer's Disease Study (C-PAS): Design and Challenge from PET Acceptance.

BACKGROUND: Large-scale preclinical Alzheimer's disease study based on ß-amyloid positron emission tomography (PET) has not been conducted in China. OBJECTIVES: Establish a cohort on Alzheimer's disease spectrum, especially the preclinical stages, and determine the factors influencing the acceptance of ß-amyloid PET scan screening in China. DESIGN: Longitudinal. SETTING: Shanghai, China. PARTICIPANTS: A total of 4386 participants were screened and 2451 participants who met enrollment criteria were eventually included in this report. MEASUREMENTS: The multidimensional data was collected, including comprehensive assessments, PET and magnetic resonance imaging scans, genetics, and plasma biomarkers. RESULTS: There were 571 participants in the normal cognition group, 625 participants in the subjective cognitive decline group, 155 participants in the objectively defined subtle cognitive decline group, 501 participants in the mild cognitive impairment group, 471 participants in Alzheimer's disease group, and 128 participants with cognitive impairment from other known causes. Significant differences in demographics, florbetapir PET, APOE, and neuropsychological tests were found among the groups. Eight hundred and seventeen participants (33.3%) completed the florbetapir PET scanning. Non-demented individuals with higher age, lower education years, male, with a family history of dementia, and higher self-report depression prefer to undergo PET scans. Acceptance of PET scans did not correlate with objectively assessed cognitive impairment. CONCLUSIONS: The Chinese Preclinical Alzheimer's Disease Study was designed to establish a large-scale cohort with comprehensive data collection. Our findings may help to understand the factors affecting the acceptance of ß-amyloid PET in urban areas of China and help us address the low acceptance challenge.

Synchronous behaviour in network model based on human cortico-cortical connections.

OBJECTIVE: We consider a network topology according to the cortico-cortical connection network of the human brain, where each cortical area is composed of a random network of adaptive exponential integrate-and-fire neurons. APPROACH: Depending on the parameters, this neuron model can exhibit spike or burst patterns. As a diagnostic tool to identify spike and burst patterns we utilise the coefficient of variation of the neuronal inter-spike interval. MAIN RESULTS: In our neuronal network, we verify the existence of spike and burst synchronisation in different cortical areas. SIGNIFICANCE: Our simulations show that the network arrangement, i.e. its rich-club organisation, plays an important role in the transition of the areas from desynchronous to synchronous behaviours.

A cross-sectional study of the knowledge, attitude, and practice of patients aged 50 years or above towards herpes zoster in an out-patient setting.

INTRODUCTION: There has been limited research on the knowledge of and attitudes about herpes zoster in the Hong Kong population. This study aimed to investigate the knowledge, attitude, and practice of patients aged 50 years or above towards herpes zoster and its vaccination. METHODS: This was a cross-sectional study in the format of a structured questionnaire interview carried out in Sai Ying Pun Jockey Club General Outpatient Clinic in Hong Kong. Knowledge of herpes zoster and its vaccination was assessed, and patient attitudes to and concerns about the disease were evaluated. Factors that affected a decision about vaccination against herpes zoster were investigated. RESULTS: A total of 408 Hong Kong citizens aged 50 years or above were interviewed. Multiple regression analysis revealed that number of correct responses regarding knowledge about herpes zoster was positively correlated with educational attainment (B=0.313, P=0.026) and history of herpes zoster (B=0.408, P=0.038), and negatively correlated with age (B= -0.042, P<0.001) and male gender (B= -0.396, P=0.029). Answers to several questions revealed a sizable number of misconceptions about the disease. Among all respondents, 35% stated that they were worried about getting the disease, and 17% would consider vaccination against herpes zoster. CONCLUSIONS: Misconceptions about herpes zoster were notable in this study. More health education is needed to improve the understanding and heighten awareness of herpes zoster among the general public. Although the majority of participants indicated that herpes zoster would have a significant impact on their health, a relatively smaller proportion was actually worried about getting the disease. Further studies on this topic should be encouraged to gauge the awareness and knowledge of herpes zoster among broader age-groups.

Prophylactic thyroidectomy in ethnic Chinese patients with multiple endocrine neoplasia type 2A syndrome after the introduction of genetic testing.

OBJECTIVE: To evaluate the impact of genetic testing in the management of familial multiple endocrine neoplasia 2A patients. DESIGN: Retrospective study. SETTING: University teaching hospital, Hong Kong. PATIENTS: Twenty-two patients from eight multiple endocrine neoplasia 2A families underwent prophylactic total thyroidectomy based on a positive RET mutation genetic testing. All mutations were located at codon 634 of exon 11. Nineteen patients had preoperative basal serum calcitonin measured, and the 12 with normal levels had pentagastrin stimulation tests. Preoperative thyroid ultrasound examination was performed for 17 patients. RESULTS: There were 13 females and 9 males with a median age of 25.1 (range, 6.1-71.9) years. Histopathology revealed medullary thyroid carcinoma in 17 (77%), C-cell hyperplasia in four (18%), and normal pathology in one (5%) of the patients. Five patients with either C-cell hyperplasia or normal pathology were among the youngest (age range, 6-9 years). The youngest patient with medullary thyroid carcinoma was nearly 9 years old. The median size of medullary thyroid carcinomas was 8.3 (range, 0.1-18) mm, but there were no lymph node metastases. Of 15 patients with normal basal calcitonin levels, 10 had medullary thyroid carcinoma, though two tested negative with the pentagastrin-stimulated calcitonin assay. Five of six patients with normal preoperative ultrasonographic examinations had medullary thyroid carcinoma. Three (14%) of the patients were prescribed long-term calcium and vitamin D supplementation. After a median follow-up of 49 (range, 13-128) months, no patient had recurrence of medullary thyroid carcinoma. CONCLUSIONS: Genetic testing has replaced conventional biochemical and radiological modalities to identifying multiple endocrine neoplasia 2A carriers, in order to offer them prophylactic thyroidectomy. Chinese multiple endocrine neoplasia 2A patients with codon 634 mutation seem to have less aggressive forms of medullary thyroid carcinoma, for whom prophylactic thyroidectomy can be considered at the age of 8 years.

Evaluation of an Internet addiction treatment program for Chinese adolescents in Hong Kong.

This paper described an indigenous multi-level counseling program designed for young people with Internet addiction problems based on the responses of 59 clients. Regarding objective outcome evaluation, pretest and posttest data generally showed that the Internet addiction problems of the participants decreased after joining the program and there were some slight positive changes in the parenting attributes. For the subjective outcome evaluation findings, participants generally perceived that the program was helpful. Findings based on these two evaluation strategies suggest this multi-level indigenous counseling program has promise for helping young people with Internet addiction problems.

Internet addiction in Chinese adolescents in Hong Kong: assessment, profiles, and psychosocial correlates.

Internet addiction behavior was examined in 6,121 Chinese primary and secondary school students in Hong Kong based on the assessment frameworks of Ivan Goldberg and Kimberly Young. Results showed that scales derived from both frameworks (CIA-Goldberg Scale and CIA-Young Scale) were internally consistent and evidence supporting their validity was found. Descriptive statistical analyses revealed that roughly one-fifth of the respondents could be classified as Internet addicted based on either scale. Further analyses showed that Internet-addicted and -nonaddicted respondents differed in their Internet use and related behavior. Logistic regression analyses showed that engagement in certain on-line activities (such as playing on-line games and downloading software) and replacement of pastimes activities (such as watching TV and going out with friends) with Internet activities predicted a higher probability of Internet addiction.

Trunk muscle training, posture fatigue, and performance in laparoscopic surgery.

PURPOSE: To investigate the effect of trunk muscle endurance training on the perception of back postural fatigue and performance of a laparoscopic task. MATERIALS AND METHODS: Thirty-one medical students (28 men and 13 women) with no laparoscopic surgical experience were randomly assigned to either a training group or a control group. Participants in the training group underwent a 6-week, 18-session trunk (abdominal and back muscle) endurance training program, whereas participants in the control group did not. Performance by all participants was assessed on a simulated laparoscopic task under varying conditions of low back postural fatigue, both before and after the training program. RESULTS: Participants in the training group showed significant improvements in trunk endurance after the 6-week, trunk endurance training program (P<0.05), whereas those in the control group did not. The improvements in trunk endurance were accompanied by significantly reduced perceptions of discomfort (P< .001) and fewer errors during performance of the laparoscopic task. (P<0.02), whereas no significant changes occurred for the control group (P>0.05). CONCLUSION: Increasing trunk endurance can increase postural fatigue and discomfort during simulated laparoscopic tasks, which may assist in the management of errors during laparoscopy.

Treatment outcomes in anaplastic thyroid carcinoma: survival improvement in young patients with localized disease treated by combination of surgery and radiotherapy.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is a notoriously aggressive malignancy associated with a highly lethal clinical course despite therapeutic intervention. Our present study attempts to identify factors that could potentially improve therapeutic strategies by analyzing the clinicopathological features, treatment and outcome of ATC patients managed over the past four decades at our institution. METHODS: Fifty patients with biopsy-proven ATC during the period 1966 to 2006 were studied. All patients were managed with surgery, radiotherapy, chemotherapy and/or chemoradiation. Survival was calculated by the Kaplan-Meier method. Potential factors affecting survival were compared by the log rank test. RESULTS: Most patients (88%) presented with a neck mass; 17 patients (34%) also had cervical lymphadenopathy. Distant metastases were clinically present in 9 (18%). Median survival was 97 days, whereas the 1- and 3-year survival was 14% and 8%, respectively. On univariate analysis, patients aged

Implicit motor learning in surgery: implications for multi-tasking.

BACKGROUND: Implicitly learned motor skills are characterized by minimal conscious knowledge of the movements involved and stable performance despite stress, fatigue, or multi-tasking. In contrast, explicitly learned motor skills are characterized by conscious knowledge of the movements and performance that tends to be less stable under stress, fatigue, and multi-tasking. We examined the acquisition of a basic surgical skill in three observational learning treatment conditions designed to accomplish implicit or explicit motor learning. We then tested performance in conditions that emulated multi-tasking in the operating theater. Our intention was to elaborate current understanding of implicit and explicit processes that underpin observational learning in the surgical environment. METHODS: Thirty-six novice adults were assigned randomly to an observation-only, an instructed-observation, or a guided-observation treatment condition, in which they learned to perform a suturing and knot-tying task in a Learning Phase. Their performance during multi-tasking was then assessed objectively by motion analysis during a Test Phase. RESULTS: In the Learning Phase, performance improved equally in the treatment conditions throughout learning, with participants using fewer hand movements and completing the task more quickly. Participants in the observation-only and the guided-observation treatment condition, however, reported significantly less movement-related knowledge than participants in the instructed-observation condition. In the Test Phase, participants in the instructed-observation condition exhibited slower completion times and more hand movements when they were required to multi-task, whereas in the observation-only and the guided-observation treatment condition, participants showed stable performance. CONCLUSIONS: A surgical skill that is learned by observation alone or by observation accompanied by guidance to reduce the number of errors that are committed tends to be learned implicitly and to have stable performance during multi-tasking. The efficacy of observation for acquiring technical skills implies that, at least for some skills, verbal instructions may not be necessary.

Early versus delayed-interval laparoscopic cholecystectomy for acute cholecystitis: a metaanalysis.

BACKGROUND: Early laparoscopic cholecystectomy has been advocated for the management of acute cholecystitis, but little evidence exists to support the superiority of this approach over delayed-interval operation. The current systematic review was undertaken to compare the outcomes and efficacy between early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis in an evidence-based approach using metaanalytical techniques. METHODS: A search of electronic databases, including MEDLINE and EMBASE, was conducted to identify relevant articles published between January 1988 and June 2004. Only randomized or quasi-randomized prospective clinical trials in the English language comparing the outcomes of early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis were recruited. Both qualitative and quantitative statistical analyses were performed. The effect size of outcome parameters was estimated by odds ratio or weighted mean difference where feasible and appropriate. RESULTS: A total of four clinical trials comprising 504 patients met the inclusion criteria. Failure of conservative treatment requiring emergency cholecystectomy occurred for 43 patients (23%) in the delayed group. Metaanalyses demonstrated a significantly shortened total length of hospital stay in the early group (weighted mean difference, -1.12; 95% confidence interval [CI], -1.42 to -0.99; p < 0.001). Pooled estimates did not show any significant differences between the two approaches in terms of operation time, conversion rate, overall complication rate, incidence of bile leakage, and intraabdominal collection. CONCLUSIONS: The safety and efficacy of early and delayed-interval laparoscopic cholecystectomy for acute cholecystitis were comparable. Because evidence suggested that early laparoscopic cholecystectomy reduced the total length of hospital stay and the risk of readmissions attributable to recurrent acute cholecystitis, it is therefore a more cost-effective approach for the management of acute cholecystitis.

Resection of phaeochromocytoma extending into the right atrium in a patient with multiple endocrine neoplasia type 2A.

We report the first case of successful surgical resection of a malignant phaeochromocytoma with tumour extension into vena cava and right atrium in a patient with multiple endocrine neoplasia type 2A. A 21-year-old woman with genetic confirmation of multiple endocrine neoplasia type 2A syndrome was diagnosed with a very rare case of malignant phaeochromocytoma with tumour thrombus extension into vena cava and right atrium causing Budd-Chiari syndrome. It posed a challenge to the surgeons with regard to complete tumour resection and vascular control. Reviewing the limited literature, surgical resection by means of cardiopulmonary bypass with hypothermic circulatory arrest has been reported with success in phaeochromocytoma with advance vascular involvement. Adopting this approach, adrenalectomy with complete thrombus excision by inferior vena cava exploration and right atriotomy were performed successfully by a multidisciplinary team.

Double-clad Cr4+:YAG crystal fiber amplifier.

A novel double-clad Cr4+:YAG crystal fiber is demonstrated by use of a codrawing laser-heated pedestal growth method. Up to 10 dB of gross gain at a wavelength of 1.52 microm is achieved at a pump power of 0.83 W, which, to our knowledge, is the first Cr4+-doped fiber amplifier in the optical fiber communication band.

Mediation of beta-endorphin in exercise-induced improvement in insulin resistance in obese Zucker rats.

BACKGROUND: Aerobic exercise including treadmill running has long been used to successfully treat and/or prevent insulin resistance and type-2 diabetes. Increase of plasma beta-endorphin is observed with exercise. The present study was designed to clarify the role of endogenous beta-endorphin in exercise-induced improvement in insulin resistance. METHODS: We used a moderate exercise program consisting of treadmill running at 20 m/min and 0% grade for 1 h/day, 7 days/week, for 8 weeks. Plasma glucose concentration was assessed by the glucose oxidase method. The enzyme-linked immunosorbent assay was performed to quantify the plasma level of beta-endorphin-like immunoreactivity (BER). The glucose disposal rate (GDR) was measured by the hyperinsulinemic euglycemic clamp technique. Changes of the insulin signaling in isolated soleus muscle were then detected by immunoprecipitation and immunoblotting. RESULTS: An increase of plasma BER in parallel with the reduction of plasma glucose was obtained in exercise-trained obese Zucker rats. Different from a marked reduction in sedentary obese rats, the value of insulin-stimulated GDR obtained from the exercised obese rats was reversed to near that of the sedentary lean group, eight weeks after the last period of exercise. This effect of exercise was inhibited by naloxone or naloxonazine at doses sufficient to block opioid micro-receptors. Signaling-related defects in the soleus muscle of sedentary obese Zucker rats, which impaired glucose transporter subtype 4 (GLUT 4), included decreased phosphorylation of insulin receptor substrate (IRS)-1, as well as an attenuated p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3 kinase) and Akt serine phosphorylation. In contrast, exercise training failed to modify the levels of insulin receptor (IR), IRS-1, and IR tyrosine autophosphorylation in obese Zucker rats. CONCLUSION: Enhanced insulin sensitivity via exercise training might be mediated by endogenous beta-endorphin through an increase of postreceptor insulin signaling related to the IRS-1-associated PI3-kinase step that leads to the enhancement of GLUT 4 translocation and improved glucose disposal in obese Zucker rats.

Infusion of beta-endorphin improves insulin resistance in fructose-fed rats.

In an attempt to probe the effect of beta-endorphin on insulin resistance, we used Wistar rats that were fed fructose-rich chow to induce insulin resistance. Insulin action on glucose disposal rate (GDR) was measured using the hyperinsulinemic euglycemic clamp technique, in which glucose (variable), insulin (40 mU/kg/min), and beta-endorphin (6 ng/kg/min) or vehicle were initiated simultaneously and continued for 120 min. A marked reduction in insulin-stimulated GDR was observed in fructose-fed rats compared to normal control rats. Infusion of beta-endorphin reversed the value of GDR, which was inhibited by naloxone and naloxonazine each at doses sufficient to block opioid mu-receptors. Opioid mu-receptors may therefore be activated by beta-endorphin to improve insulin resistance. Next, soleus muscle was isolated to investigate the effect of beta-endorphin on insulin signals. Insulin resistance in rats induced by excess fructose was associated with the impaired insulin receptor (IR), tyrosine autophosphorylation, and insulin receptor substrate (IRS)-1 protein content in addition to the significant decrease in IRS-1 tyrosine phosphorylation in soleus muscle. This impaired glucose transportation was also due to signaling defects that included an attenuated p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3-kinase) and Akt serine phosphorylation. However, IR protein levels were not markedly changed in rats with insulin resistance. beta-endorphin infusion reversed the fructose-induced decrement in the insulin-signaling cascade with increased GDR. Apart from IR protein levels, infusion of beta-endorphin reversed the decrease in protein expression for the IRS-1, p85 regulatory subunit of PI3-kinase, and Akt serine phosphorylation in soleus muscle in fructose-fed rats. The decrease in insulin-stimulated protein expression of glucose transporter subtype 4 (GLUT 4) in fructose-fed rats returned to near-normal levels after beta-endorphin infusion. Infusion of beta-endorphin may improve insulin resistance by modulating the insulin-signaling pathway to reverse insulin responsiveness.

Multiple endocrine neoplasia type 2B in a Chinese patient.

Multiple endocrine neoplasia type 2B syndrome is rarely reported in Chinese patients. A 25-year-old Chinese male presented with full-blown clinical features of this syndrome, including bilateral phaeochromocytomas, medullary thyroid carcinoma, and characteristic phenotypic features. One-stage surgical treatment was performed and subsequent genetic analysis confirmed a point mutation at codon 918 in exon 16 of the RET proto-oncogene. The mutation was arising de novo as there was no corresponding mutation found in both his parents or younger sister. Data published to date suggest there is no difference in the genetic and pathophysiologic basis, nor clinical characteristics of multiple endocrine neoplasia type 2B in Chinese patients. As the disease can be lethal, early diagnosis by prompt recognition of the characteristic phenotypic features followed by surgical treatment should improve the outcome. Family screening is essential to identify at-risk family members for prophylactic treatment.

Laparoscopic resection of a pancreatic polypeptidoma with a solitary liver metastasis.

Pancreatic neuroendocrine tumor is an uncommon disease, and surgery is the only potentially curative treatment even when there is hepatic metastasis. A patient undergoing concomitant laparoscopic distal pancreatectomy and hepatectomy for pancreatic polypeptidoma with a solitary liver metastasis is reported.

Surgical treatment of pancreatic insulinomas in the era of laparoscopy.

BACKGROUND: Laparoscopic resection has been increasingly reported for pancreatic insulinomas. This report evaluates our experience with surgical treatment for pancreatic insulinomas in this era of laparoscopy and reviews the application, safety, and outcome of this surgical approach reported in the literature. METHODS: In a consecutive series of 10 patients with pancreatic insulinomas, laparoscopic resection was performed for selected patients after routine preoperative localizations. The outcome of this operative strategy was reviewed together with reported cases involving laparoscopic resection of pancreatic insulinomas. RESULTS: Laparoscopic distal pancreatectomy or enucleation was performed for four patients with tumors located at the body or tail of the pancreas, whereas open enucleation was performed for six patients with tumors located at the pancreatic head. Pancreatic leak developed in one laparoscopic and two open enucleations. A review of reported cases in the literature showed that 61 of 69 attempted laparoscopic pancreatic resections for insulinomas were performed successfully. All except two tumors were located at the body or tail of the pancreas. For 42 cases with detailed information, 41 tumors at the pancreas body or tail were removed successfully by enucleation (n = 24) or distal pancreatic resection (n = 17), and one tumor at the pancreatic head was enucleated successfully. Pancreatic fistula, the most frequent complication, occurred in 8 (19%) of 42 laparoscopic resections. CONCLUSIONS: Laparoscopic resection of pancreatic insulinomas is safe and feasible for tumors located at the body or tail of the pancreas. Its application for tumors located at the pancreatic head needs further evaluation.

Minimally invasive endoscopic-assisted parathyroidectomy for primary hyperparathyroidism.

BACKGROUND: Minimally invasive surgery for primary hyperparathyroidism (pHPT) depends on both an accurate preoperative localization and the availability of intraoperative parathyroid hormone monitoring. METHODS: Patients with sporadic pHPT and one unequivocally enlarged parathyroid gland on preoperative imaging underwent endoscopic-assisted parathyroidectomy. Intraoperative rapid parathyroid hormone (quick PTH) monitoring was performed, and surgical success was confirmed when there was a >50% decrease in quick PTH level 10 min after excision as compared with the baseline level at induction. The surgical outcome and the use of preoperative localization, together with the role played by quick PTH assay in enhancing the operative success, were evaluated. RESULTS: From 1999 to 2002, 66 of 107 patients (62%) were selected for this approach. The accuracy of 99mTc-Sestamibi scintigraphy and ultrasonography was 97% and 70%, respectively. Conversion was required in four cases due to technical problems, and four additional patients failed to show a significant decline in quick PTH levels postexcision. Two patients underwent cervical exploration without the finding of any additional pathology, and another two patients had a delayed drop in quick PTH that was confirmed 30 min postexcision. All patients had a solitary adenoma and were cured of hypercalcemia during a median follow-up of 9 months. CONCLUSIONS: Minimally invasive endoscopic-assisted parathyroidectomy can be performed expeditiously in a select group of patients based on 99mTc-Sestamibi scintigraphy. The use of quick PTH assay can ensure surgical success, but careful interpretation of the results is mandatory.

Objective assessment of technical skills of surgical trainees in Hong Kong.

BACKGROUND: The need for assessment of technical skills is well recognized and objective methods of assessment are currently under investigation in the UK. The applicability of these assessment tools to trainees with a different training background in another country was examined. METHODS: Six bench-top models for basic surgical trainees (BSTs) and eight for higher surgical trainees (HSTs) (five in common) were assessed for construct validity in 70 subjects. Objective assessment methods included motion analysis using the Imperial College Surgical Assessment Device, Objective Structured Assessment of Technical Skills and Minimally Invasive Surgical Trainer in Virtual Reality. RESULTS: All models shared between BSTs and HSTs exhibited construct validity (range P = 0.050 to P < 0.001). Of the three modules for HSTs alone, only one gave significant results (small bowel anastomosis; P = 0.005). Reasons for this were sought. CONCLUSION: The methods of objective technical skills assessment of trainees in the UK are applicable to those in Hong Kong. Their use should be promoted and the tracking of skills development encouraged.