Recommendations for eligibility criteria concerning bariatric and metabolic surgical and endoscopic procedures for obese Hong Kong adults 2024: Hong Kong Society for Metabolic and Bariatric Surgery Position Statement.

The surgical management of obesity in Hong Kong has rapidly evolved over the past 20 years. Despite increasing public awareness and demand concerning bariatric and metabolic surgery, service models generally are not standardised across bariatric practitioners. Therefore, a working group was commissioned by the Hong Kong Society for Metabolic and Bariatric Surgery to review relevant literature and provide recommendations concerning eligibility criteria for bariatric and metabolic interventions within the local population in Hong Kong. The current position statement aims to provide updated guidance regarding the indications and contraindications for bariatric surgery, metabolic surgery, and bariatric endoscopic procedures.

Micro-engineered remote palpation device for assessing tissue compliance.

This paper concerns the operation of the actuator for a prototype micro-engineered mechanical palpation device for deployment via a cystoscope to measure the dynamic mechanical properties of the prostate gland in vivo. The subassembly consists of a 400x200 microm silicon (Si) piston manufactured using deep reactive ion etching (DRIE) housed within an anodically bonded glass-Si-glass sandwiched housing. The micro-channel on the Si layer was formed by powder blasting and contains the micro-piston with one end pointing to the side of the housing and the other facing a via hole leading to a capillary tube. The opening on the side of the housing was sealed by a 5 microm thick silicone membrane which acts to retain the micro-piston and act as a return spring. A 320 microm diameter capillary forms the connection between the micro-channel and a micro-syringe which is operated by a programmable syringe pump to produce a reciprocating action. A pressure sensor is connected along the capillary tube to measure the dynamic pressure within the system. The micro-piston has already been used, separately actuated to measure the dynamic mechanical properties of known viscoelastic materials and prostate tissue. The purpose of the present work is to assess the functionality of the actuator assembly.

MicroAlbuminuria Prevalence Study (MAPS) in hypertensive type 2 diabetic patients in Hong Kong.

OBJECTIVES: To assess the prevalence of macroalbuminuria and microalbuminuria, and the level of blood pressure control in patients with type 2 diabetes and hypertension in Hong Kong. DESIGN: Cross-sectional clinic-based epidemiological study. SETTING: Six medical centres (including two public hospital diabetes centres) in Hong Kong. PATIENTS: Recruited from the medical centres from April to November 2002, after excluding those with bacteriuria and haematuria. MAIN OUTCOME MEASURES: Body mass index; blood pressure; levels of blood glucose, macroalbuminuria, and microalbuminuria; treatments for hypertension and diabetes. RESULTS: The as per-protocol recruited population of 437 hypertensive type 2 diabetic patients had a mean age of 61.7 (standard error, 0.5) years. Overall, the prevalence of diabetic nephropathy in this population was high; 18.3% had macroalbuminuria (95% confidence interval, 16.5-20.2%) and 24.9% had microalbuminuria (95% confidence interval, 22.9-27.0%). Predictive factors were advanced age, male sex, poor blood pressure control, and existing cardiovascular complications. Whilst almost all patients (96.1%) were receiving treatment for hypertension, only 25.6% had systolic/diastolic blood pressures below the 130/85 mm Hg target. CONCLUSIONS: In Hong Kong, the prevalence of microalbuminuria and macroalbuminuria is high in type 2 diabetic patients with hypertension, particularly in males and those with poorly controlled systolic blood pressure. Tight glycaemic control, antihypertensive therapy, and use of renin-angiotensin system inhibitors/blockers are necessary to retard the progression of nephropathy to advanced renal disease.

In-vitro dynamic micro-probing and the mechanical properties of human prostate tissues.

In vitro macro- and micro-indentation test systems have been designed to measure the dynamic micro-mechanical properties of human prostate tissues at actuation frequencies between 5 Hz and 30 Hz, and 0.5 Hz and 20 Hz, respectively. The development of in vitro test systems was aimed at assessing the capacity of such an in vivo medical probe to provide information useful for the diagnosis of various prostate diseases. The macro-indentation test system is an established one, which we have used to determine structure-property relationships in human and canine prostate tissues and here we use it to validate a newly-developed micro-indentation test system using a tissue phantom. Mechanical testing was also carried out on sections of prostate tissue harvested from cystectomy and radical prostatectomy, diagnosed with bladder cancer and benign prostatic hyperplasia. Dynamic probing under displacement control was carried at pre-strains between 5% and 8% for macro-probing and at 5% pre-strain for micro-probing, and the general effect of pre-strain on the dynamic mechanical properties (described by the amplitude ratio between stress and strain, and the phase lag between strain and stress) of phantom and prostate tissues is presented. Specific point probing on epithelial and stromal histological components was also carried out showing a significant difference between the amplitude ratios of epithelial and stromal components for actuation frequencies exceeding 5 Hz. However, no significant difference was found between phase lags for epithelial and stromal tissues.

Design and development of the pressure ulcer nursing information system for clinical risk management.

Since 2002, hospitals have to report to Nursing Service Department, Hospital Authority Head Office on the pressure ulcer trends for risk management in Hong Kong. In line with the strategy, hospitals have designed their own patient observation records and reporting forms for monthly analysis and reporting of in-patient hospital acquired pressure ulcers. The incidence rates of individual hospital and its specialties are then calculated manually or using electronic spread sheets. However, the diversity in data definition and vocabulary use generates difficulties in communication among professionals and hospital managers. The development of the system would help to standardize the requirements and to reduce the time required for generating trends and ulcer information. The system also lays the foundation for future systems integration with the changing information system infrastructure.

Comparative assessment of water quality parameters of mariculture for fish production in Hong Kong Waters.

The objective of the study is to evaluate the effect of fish cultivation on water quality in fish culture zone (FCZ) and analysed by Principle Component Analysis (PCA). 120 surface water samples were collected from Hong Kong Waters (60 samples in Victoria Harbour and another 60 in Ma Wan FCZ). Significant difference was found in dissolved oxygen (MW: 59.6%; VH: 81.3%), and Escherichia coli (MW: 465 CFU/100 ml; VH: 162.5 CFU/100 ml). Three principle components are responsible for water quality variations in the studying sites. The first component included E. coli (0.625) and dissolved oxygen (0.701). The second included E. coli (0.387) and ammonical-nitrogen (0.571). The third included E. coli (0.194) and ammonical-nitrogen (0.287). This framework provides information to assess the relative contribution of eco-aquaculture to nutrient loads and the subsequent risk of eutrophication. To conclude, a rigorous monitoring of water quality is necessary to assess point and nonpoint source pollution. Besides, appropriate remediation techniques should be used to combat water pollution and achieve sustainability.

Limitation of long-term atrial pacing via floating ring electrode using overlapping biphasic impulse stimulation in ambulatory-paced patients.

Long-term atrial pacing with overlapping biphasic impulse stimulation using floating atrial electrodes is limited in its use by the high rate of intermittent failure to capture the atrium and by the occurrence of diaphragmatic stimulation in ambulatory patients.

Experience with a single-pass, dual-electrode implantable atrial defibrillator lead for maintaining sinus rhythm in patients with recurrent atrial fibrillation.

The implantable atrial defibrillator is a new potential nonpharmacologic treatment for recurrent atrial fibrillation. The results of this study suggest that a simplified lead configuration, with a single-pass, dual-electrode atrial defibrillation lead can be used for both atrial fibrillation detection and defibrillation with an implantable atrial defibrillator.

Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis.

The drug susceptibilities of 105 isolates/strains of Mycobacterium tuberculosis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional agar proportion method. The agreement rates between the two methods were 99.0% for streptomycin, 95.2% for isoniazid and 100% for rifampin. The mean times to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detection were 10.8 days (mean) and 21 days respectively. Thus, these data have demonstrated that the automated, non-radiometric MB/BacT system is an efficient, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method.

Developments in sensor-driven pacing.

This article reviews the recent major developments in the field of rate adaptive pacing. Including, the improved instrumentation of existing sensors, the use of multiple sensors to enhance sensor specificity or sensitivity, and the automation of sensor calibration. The physiologic benefits and programming of rate adaptive pacing are reviewed.

Interference of cellular phones with implanted permanent pacemakers.

BACKGROUND AND HYPOTHESIS: Occasional reports have suggested that cellular phones may interfere with permanent pacemakers. Our investigation sought to determine systematically the effects of commercially available cellular phones on the performances of different pacing modes and sensing lead configurations of permanent implanted pacemakers. METHODS: We conducted the study in 29 patients implanted with single- or dual-chamber bipolar rate-adaptive permanent pacemakers (a total of nine different models and six different sensors: minute ventilation, activity sensing using either accelerometer or piezoelectric crystal, QT and oxygen saturation sensing) from four different manufacturers. Three different cellular phones with analog or digital coding with maximum power from 0.6 to 2 W were used to assess the effect of pacemaker interference. Each cellular phone was positioned at (1) above the pacemaker pocket, (2) the ear level ipsilateral to the pacemaker pocket, and (3) the contralateral ear level. Surface electrocardiograms, intracardiac electrograms, and marker channels were recorded where possible during the following maneuvers at each position: (1) calls made by a stationary phone to cellular phone, and (2) calls made from the cellular phone to a stationary phone. A total of eight different pacing modes [DDD(R), VDD(R), AAI(R) and VVI(R)] in both unipolar and bipolar sensing configurations was tested. RESULTS: Interference was demonstrated during cellular phone operation in 74 of 2,418 (3.1%) episodes in eight patients. Three types of interference were observed: inhibition of pacing output, rapid ventricular tracking in DDD(R) or VDD(R) mode, and asynchronous pacing. All were observed only with the cellular phone positioned above the pacemaker pocket. Interference occurred prior to and after the termination of the ringing tone of the cellular phone in 57% of cases. Cellular phones with either digital or analog technology could cause interference. Unipolar atrial lead was most susceptible to interference (relative frequency of interference: unipolar 1.8%, bipolar 0.4%, p < 0.05; atrial 2.9%, ventricular 1%, p < 0.05). There was no sensor-driven rate acceleration during all tests. In all patients, reprogramming of the sensitivity level successfully prevented cellular phone interference. CONCLUSIONS: Commercially available cellular phones can cause reversible interference to implanted single- or dual-chamber permanent pacemakers. The effect is maximal with high atrial unipolar sensitivity, especially in single pass VDD(R) systems. Both digital and analog cellular phones can lead to interference. Pacemaker interference can occur prior to a warning sign (ringing tone) of the phone and may have significant implications in patient safety.

The variable presentation and early recognition of anorexia nervosa in Hong Kong.

One of the western diagnostic criteria for anorexia nervosa is a 'morbid or intense fear of fatness', which is absent in some Chinese anorexic patients in Hong Kong. As a result, patients often visit non-psychiatric doctors and have extensive investigations performed. By the time they are referred to psychiatrists, some may already have reached an advanced stage of illness. In this report of two patients with anorexia nervosa, we attempt to illustrate the variable presentation of anorexic patients in Hong Kong, and to alert health professionals to the early recognition and treatment of this potentially lethal disorder.

Resin-ionomer restorative materials for children: a review.

Hybrid restorative materials comprising resins and components of conventional glass ionomers have been widely introduced and accepted by the dental profession in recent years. These include the resin-modified glass ionomer cements and the polyacidmodified resin composites or compomers. They are developed in an attempt to overcome the problems of traditional restoratives, such as moisture sensitivity and reduced early strength, while at the same time maintaining their clinical advantages of command setting, adhesion to tooth structures, adequate strength to occlusal load, fluoride release and aesthetics. This paper reviews the development, composition and properties of these new materials. Their clinical performance appears to be promising and they should be considered as good alternatives to amalgam and other conventional restorative materials in the future.

Solid-phase extraction-fluorimetric high performance liquid chromatographic determination of domoic acid in natural seawater mediated by an amorphous titania sorbent.

The feasibility of using sol-gel amorphous titania (TiO2) as a solid-phase sorbent for the pre-concentration of domoic acid (DA), a potent amnesic shellfish poisoning (ASP) toxin, directly from seawater was explored. The sol-gel titania material is able to adsorb DA from seawater, via the formation of ester-linkage between the carboxylic moieties of DA and the Ti-OH groups on the sorbent surface, at low pH and desorb it at high pH. The chemisorption process is not significantly interfered by the seawater matrix. The optimum pH values for the adsorption and desorption of DA were found to be pH 4 and 11, respectively. The optimal sorbent loading for the batch-type solid-phase extraction of DA was 0.67 mg-TiO2 ng-DA(-1) and adsorption equilibrium was achieved in 2 h at room temperature. The desorbed DA in 500 microL of 0.1 M alkaline borate buffer can be directly derviatized by 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) in aqueous media for fluorimetric HPLC quantification. Analyte recovery, repeatability and detection limit of this titania SPE-fluorimetric HPLC determination are 89%, 6.2% and 120 pg-DA mL(-1) (n=7, P<0.05), respectively, for a sample volume of 30 mL. This titania SPE technique should also be applicable to the pre-concentration of other polar carboxylate- and phosphonate-containing biomolecules and pharmaceuticals in complex and interfering environmental sample matrices.

Delayed exercise rate response kinetics due to sensor cross-checking in a dual sensor rate adaptive pacing system: the importance of individual sensor programming.

By cross-checking the relative sensor activation between a nonspecific and specific sensor during extraneous interference, a multisensor rate adaptive pacemaker may be able to limit inappropriate rate responses. The effects of activity (ACT) sensor programming on rate response kinetics of a QT and ACT dual sensor VVIR pacemaker with sensor cross-checking algorithm were studied in four patients with atrial fibrillation and complete heart block. The rate adaptive setting of each sensor was individually optimized, and an equal rate contribution for the QT and ACT sensors (QT = ACT) was used in the dual sensor VVIR mode. Three maximal treadmill exercise tests were performed in random order in three different VVIR modes driven by QT only, QT = ACT, and in the dual sensor mode with the most sensitive (low threshold) ACT setting. In the two dual sensor modes, the time for onset of rate response (delay time) was reduced (both < 15 sec) compared with QT only VVIR mode (233 +/- 70 sec). However, the time to 50% of rate response in the low ACT threshold dual sensor mode was delayed compared with to QT = ACT (450 +/- 110 [95% confidence interval 234-666] vs 311 +/- 103 [109-513]sec, P < 0.05) and was similar to the QT only mode (401 +/- 120 [166-636]sec). The time to reach 90% of rate response was similar in the three modes tested. The resting activity counts registered by the ACT sensor were < 5 and 16 +/- 2 counts/min in the optimally programmed and low threshold ACT settings, respectively. This resulted in sensor cross-checking at rest in the overprogrammed dual sensor VVIR mode, thereby limiting the rate response. Thus, the combined sensor system provides a faster initial response to exercise than the QT only sensor. Programming the ACT threshold to low will prevent this faster response because of sensor cross-checking.

Comparative evaluation of acute and long-term clinical performance of two single lead atrial synchronous ventricular (VDD) pacemakers: diagonally arranged bipolar versus closely spaced bipolar ring electrodes.

Floating P wave sensing can be derived from bipolar atrial electrodes with different electrode configurations, although the relative clinical efficacy of these methods of atrial sensing has not been studied. We evaluated 32 sex and age matched patients with advanced AV block who received AV synchronous pacers using either a single lead with diagonally arranged bipole (Unity VDDR, Model 292, Intermedics Inc.) or closely spaced bipolar complete ring electrodes (Thera VDD, Model 8948, Medtronic Inc.). The total surface area of the atrial electrodes were 17.2 and 25 mm2, and the highest programmable atrial sensitivities were 0.1 and 0.25 mV, respectively. Atrial electrogram amplitude and sensing threshold were evaluated at implant and at each follow-up clinic visit (1, 3, and 6 months). Stability of atrial sensing was assessed during physical maneuvers, treadmill exercise test, and Holter recording. Atrial electrogram amplitude at implantation was higher in the Thera VVD (2.08 +/- 0.79 vs 1.45 +/- 0.59 mV in Unity VDDR; P < 0.05), but the value of atrial sensing threshold was lower during follow-up than Unity VDDR. P wave undersensing was additionally observed with both pacemakers during physical maneuvers and exercise testing (6%-19% of patients). Two and four patients had atrial undersensing on Holter in the Unity VDDR and Thera VDD, respectively, and the percentage P wave undersensing were 0.88% +/- 2.41% versus 3.63% +/- 8.16%, respectively. Reprogramming of the atrial sensitivity in the Unity VDDR and the use of investigational software allowing 0.18 mV atrial sensitivity to be programmed in the Thera VDD substantially reduced the percentage of P wave undersensing on Holter to 0.46% +/- 1.67% and 0.10% +/- 0.24%, respectively. Beginning at discharge with a programmed atrial sensitivity level at least twice the sensing margin, the mean atrial sensitivity level was reprogrammed from 0.29 to 0.26 mV for Unity VDDR and 0.33 to 0.24 mV for Thera VDD at 6 months. There was no incidence of atrial oversensing. Despite differences in atrial amplitudes at implantation between the diagonally arranged bipole and closely spaced full ring single lead systems, the clinical performances of atrial sensing were similar at an appropriately high atrial sensitivities. The absence of atrial oversensing suggests that single pass VDD pacemakers should probably be programmed at the highest available atrial sensitivity to ensure adequate P wave sensing as guided by physical maneuvers and Holter recording to minimize the need of subsequent reprogramming.

Cardiac output is a sensitive indicator of difference in exercise performance between single and dual sensor pacemakers.

Although multisensor pacing may compensate the inadequacy of rate adaptation in a single sensor system, the clinical role of multisensor driven rate adaptive pacing remains unclear. We compared the performance between single sensor and dual sensor driven pacemakers using exercise cardiac output (CO) as a marker of cardiac performance. Eight patients with a mean age of 63 +/- 3 years implanted with a dual sensor pacemaker driven by combined activity (ACT) and QT interval sensors were studied in the ACT-, QT- only and the dual QT + ACT-VVIR modes. Patients performed submaximal and maximal exercise tests with CO assessed by carbon dioxide rebreathing method. Comparing the HR response based on the change in metabolic workload, the ACT-VVIR "overpaced," the QT-VVIR "underpaced," and the QT + ACT-VVIR achieved the best approximation to normal. The percentages of CO increase in ACT-VVIR and QT + ACT-VVIR modes over resting CO were higher at 1 minute of exercise (295 +/- 85% and 165 +/- 49%, respectively) compared to the QT-VVIR mode (81 +/- 40%, P < or = 0.05). During exercise, stroke volume changes from baseline were similar between ACT-VVIR and QT + ACT-VVIR modes, but a compensatory increase in stroke volume occurred in the QT-VVIR mode during submaximal exercise (50 +/- 11 mL vs 24 +/- 17 mL in the QT + ACT-VVIR and 14 +/- 4 in ACT-VVIR, P < or = 0.003). There was no difference in the maximal exercise workload, exercise duration and CO at the submaximal and maximal exercise between the 3 sensor modes. Thus, exercise capacity is a poor indicator of sensor performance while CO measurement is a sensitive indicator of sensor mode differences especially at low workload exercise. The ACT-VVIR gave the fastest increase in CO at start of exercise at the expanse of overpacing, whereas the "under-paced" QT-VVIR compensated for the slower rate increase by utilizing contractility reserve during submaximal exercise. Dual sensor pacing, by achieving the best heart rate to workload relationship, provided a CO response without overpacing or using contractility reserve during exercise.

A cephalic vein cutdown and venography technique to facilitate pacemaker and defibrillator lead implantation.

The aim of this study was to assess the feasibility of a cephalic vein cutdown and venography technique for implantation of a pacemaker or ICD and to determine the causes of failure of cephalic vein cutdown. In consecutive patients who underwent pacemaker or ICD implants, a modified cephalic vein guidewire technique was performed. This technique was attempted in 289 pacemaker implants and 26 ICD implants (155 men, 160 women; mean age 74 +/- 10 years). The success rate for implantation of a single chamber and a dual chamber device by using this technique alone was 84% (54/64) and 74% (185/251), respectively (P = 0.10). In an additional 7% of patients with dual chamber implant, the cephalic vein can be used for passage of the ventricular lead. A cephalic venogram was required in 82 patients and facilitated the passage of the guidewire in 62 (79%) of them. No complication related to vascular access was observed with this technique. This technique failed in 54 (17%) of 315 patients due to (1) failure of cephalic vein isolation (48%), (2) venous stenosis (24%), or (3) venous torturosity or anomalies (28%). There were no significant differences in the patient's age, sex, type of device, and the fluoroscopic time for lead placement between patients with or without successful lead placement using this technique (all P > 0.05). In conclusion, a simple modification of the cephalic vein guidewire technique together with venography has facilitated the placement of leads during pacemaker and ICD implant. This technique is safe and applicable in the majority of patients and avoids the risk of subclavian puncture.

New integrated sensor pacemaker: comparison of rate responses between an integrated minute ventilation and activity sensor and single sensor modes during exercise and daily activities and nonphysiological interference.

A dual sensor DDDR pacemaker (DX2 Model 7970, Medtronic Inc.) has integrated the rate response of minute ventilation (MV) and activity (ACT) sensors. False rate acceleration by the ACT (constrained upper rate) and MV (cross-checked by ACT) is reduced. We examined the rate response profile and rate kinetics of the automatically optimized integrated sensor by comparing with the projected rate response of ACT and MV sensors alone in nine patients. After 1 month of sensor optimization using rate profile optimization (RPO), patients underwent maximal and submaximal treadmill exercises and performed activities of daily living (ADL). The integrated sensor mode gave a faster speed of rate response with a shorter delay time, time to 50% rate response and time to 90% of rate response compared to the MV sensor during hall walk (0.37 +/- 0.08, 0.7 +/- 0.09, 1.43 +/- 0.19 vs 1.11 +/- 0.1, 1.75 +/- 0.14, 2.91 +/- 0.17 min; P < 0.05). The average maximal sensor rates were significantly more proportional for the integrated sensor mode compared with either the ACT or MV mode. There was no significant difference in both the maximal pacing rate among the three sensor modes during maximal exercise and the rate decay during recovery. During interference studies by arm swinging (30-40 swings/min) and external tapping of the pacemakers (2 taps/s), there was only a moderate increase in pacing rate by 13 +/- 9, 16 +/- 5 beats/min. Hence, the new integrated sensor with the automatic rate profile optimization algorithm resulted in improved rate response profiles during submaximal exercise and ADL compared to the individual sensor response, and the sensor blending and cross-checking algorithm made the pacemaker relatively immune to false triggering of both the ACT and MV sensors.