Role of pre-operative ureteral stent on outcomes of retrograde intra-renal surgery (RIRS): systematic review and meta-analysis of 3831 patients and comparison of Asian and non-Asian cohorts.

PURPOSE: To evaluate the outcomes of pre-stented (PS) versus non-pre-stented (NPS) patients who have undergone retrograde intrarenal surgery (RIRS) for renal calculi with subgroup analysis of Asian and non-Asian cohorts. METHODS: Protocol is registered in PROSPERO, CRD42021261123. Eligible studies identified from four electronic databases. Meta-analysis was done to enumerate the outcomes of RIRS in between PS and NPS. Secondary sub-analysis was done to look for differences in outcomes in Asian and non-Asian cohorts. RESULTS: Fourteen studies involving 3831 patients (4 prospective, 10 retrospective studies) were included. PS patients experienced higher success rates of ureteral access sheath (UAS) insertion than NPS (RR 1.09, 95% CI 1.05-1.13, p < 0.00001). PS patients had lower risk of ureteral injuries from UAS placement (RR 0.69, 95% CI 0.50-0.96, p = 0.03). No significant differences in intra- and postoperative complications between two groups were found. Stone-free rate (SFR) outcomes for residual fragment (RF) cut-off of < 1 mm and < 4 mm favoured the PS patients (RR 1.10, 95% CI 1.04-1.17, p = 0.002 for < 4 mm, RR1.10, 95% CI 1.02-1.19, p = 0.02 for < 1 mm). In the subgroup analysis, PS Asian patients had similar SFR as NPS patients for SFR(< 4 mm) but non-Asian population showed better outcomes in the PS patients for SFR(< 4 mm) (RR 1.31, 95% CI 1.13-1.52, p = 0.0005). CONCLUSIONS: This meta-analysis suggests that pre-stenting results in a higher success for UAS placement, minimising intraoperative ureteric injury, with higher overall SFR for any RF cut-off in PS cohorts. In non-Asian cohort, significant differences occurred at SFR < 4 mm but not for SFR < 1 mm. No difference was seen in our Asian cohort for any SFR cut-off in both PS and NPS patients.

Percutaneous mechanical thrombectomy in the treatment of acute iliofemoral deep vein thrombosis: a systematic review.

BACKGROUND: Conventional treatment of deep vein thrombosis (DVT) of the lower extremities by anticoagulation alone has been proven to be insufficient to prevent recurrence and post-thrombotic syndrome (PTS). Early restoration of venous patency and preservation of valvular function by endovascular surgery has been advocated. The aim of this study was to review the efficacy and safety of percutaneous mechanical thrombectomy (PMT) against catheter-directed thrombolysis (CDT) in the treatment of acute iliofemoral DVT. METHODS: Three hundred sixty-nine articles were identified through screening of the PubMed, EMBASE, and Cochrane databases from January 2006 to December 2016. RESULTS: Fifteen retrospective studies and one prospective registry, totalling 1170 patients, were recruited for qualitative synthesis. The venous patency rate ranged from 75% to 100% with mean follow-up of 12.3 months. The rates of PTS and recurrent DVT were less than 17% and 15%, respectively. The overall mortality rate was 0.26%. Compared with CDT, PMT was shown to reduce PTS at 1 year (Villalta score: 2.1 ± 3.0 in the PMT group and 5.1 ± 4.1 in the CDT group, P=0.03) and bleeding complications (packed cells transfused: 0.2 ± 0.3 units in the pharmacomechanical thrombectomy group and 1.2 ± 0.7 units in the CDT group, P<0.05). CONCLUSION: Percutaneous mechanical thrombectomy is a safe and effective treatment for acute iliofemoral DVT in terms of restoration of venous patency, prevention of DVT recurrence, and PTS. Compared with CDT alone, PMT offers a lower risk of PTS and bleeding complications.

The importance of nuclear quantum effects in spectral line broadening of optical spectra and electrostatic properties in aromatic chromophores.

In this work, we examine the importance of nuclear quantum effects on capturing the line broadening and vibronic structure of optical spectra. We determine the absorption spectra of three aromatic molecules indole, pyridine, and benzene using time dependent density functional theory with several molecular dynamics sampling protocols: force-field based empirical potentials, ab initio simulations, and finally path-integrals for the inclusion of nuclear quantum effects. We show that the absorption spectrum for all these chromophores are similarly broadened in the presence of nuclear quantum effects regardless of the presence of hydrogen bond donor or acceptor groups. We also show that simulations incorporating nuclear quantum effects are able to reproduce the heterogeneous broadening of the absorption spectra even with empirical force fields. The spectral broadening associated with nuclear quantum effects can be accounted for by the broadened distribution of chromophore size as revealed by a particle in the box model. We also highlight the role that nuclear quantum effects have on the underlying electronic structure of aromatic molecules as probed by various electrostatic properties.

Surgical management of carotid body tumor - Is Shamblin classification sufficient to predict surgical outcome?

Background The study aims to conduct a review of the surgical management of carotid body tumor. Methods Consecutive patients with CBT who received surgical interventions from January 1994 to January 2014 at our institution were reviewed. Clinical, operative, pathological and follow up information were reported. Results Twenty patients (four males; median age was 36) with 21 CBT operations were recorded during the period. One patient undertook sequential operations for bilateral CBTs. Patients had 19 neck mass, 1 incidental finding and 1 facial nerve palsy. Six CBTs (28.6%) were Shamblin class I, ten (47.6%) were class II and five (23.8%) were class III. Nine CBTs had preoperative conjunctive embolization. Two operations required internal carotid artery resection and reconstruction. Four patients received subtotal resections, while 17 achieved complete resection. Complications included two major strokes, three hoarse voice and two Horner's syndrome. Shamblin class was significant predictor of operative time, blood loss, and whether complete resection accomplished, but could not predict postoperative complication. With median follow up period of 94 months, there was no tumor recurrence found in those had complete resection. Conclusions This small cohort showed that Shamblin class was significant in predicting technical difficulties but could not predict occurrence of complications.

Effectiveness of proximal intra-operative salvage Palmaz stent placement for endoleak during endovascular aneurysm repair.

INTRODUCTION: The use of a proximal Palmaz stent is a well-recognised technique to treat proximal endoleak in endovascular aortic repair. This study aimed to report the effectiveness and safety of an intra-operative Palmaz stent for immediate type 1a endoleak in Hong Kong patients. METHODS: This case series was conducted at a tertiary hospital in Hong Kong. In a cohort of 494 patients who underwent infrarenal endovascular aortic repair from July 1999 to September 2015, 12 (2.4%) received an intra-operative proximal Palmaz stent for type 1a endoleak. Immediate and subsequent proximal endoleak on follow-up image was documented. RESULTS: Morphological review of the pre-repair aneurysm neck showed five conical, one funnel, five cylindrical and one undetermined short neck, with a median neck angle of 61 degrees (range, 19-109 degrees). Stent grafts used included seven Cook Zenith, one Cook Aorto-Uni-Iliac device, three Metronic Endurant, and one TriVascular Ovation. Eleven Palmaz stents were placed successfully as intended, but one of them was accidentally placed too low. Of the 12 type 1a endoleaks, postoperative imaging revealed immediate resolution of eight whilst four had improved. After a median follow-up of 16 (range, 1-59) months, none of the subsequent imaging showed a type 1a endoleak. The mean size of the aneurysm sac reduced from 7.4 cm preoperatively to 7.3 cm at 1 month, 6.9 cm at 6 months, 7.1 cm at 1 year, and 6.1 cm at 2 years postoperatively. None of these patients required aortic reintervention or had device-related early- or mid-term mortality. One patient required delayed iliac re-interventions for an occluded limb at 10 days post-surgery. CONCLUSION: In our cohort, Palmaz stenting was effective and safe in securing proximal sealing and fixation.

Cell tracking using phase-adaptive shape prior.

Automated tracking of cell population is very crucial for quantitative measurements of dynamic cell-cycle behaviour of individual cells. This problem involves several subproblems and a high accuracy of each step is essential to avoid error propagation. In this paper, we propose a holistic three-component system to tackle this problem. For each phase, we first learn a mean shape as well as a model of the temporal dynamics of transformation, which are used for estimating a shape prior for the cell in the current frame. We then segment the cell using a level set-based shape prior model. Finally, we identify its phase based on the goodness-of-fit of the data to the segmentation model. This phase information is also used for fine-tuning the segmentation result. We evaluate the performance of our method empirically in various aspects and in tracking individual cells from HeLa H2B-GFP cell population. Highly accurate validation results confirm the robustness of our method in many realistic scenarios and the essentiality of each component of our integrating system.

Impact of magnetic resonance imaging on preoperative planning for breast cancer surgery.

OBJECTIVES: To review the impact of preoperative breast magnetic resonance imaging on the management of planned surgery, and the appropriateness of any resulting alterations. DESIGN: Retrospective review. SETTING: A private hospital in Hong Kong. PATIENTS; For the 147 consecutive biopsy-proven breast cancer patients who underwent preoperative magnetic resonance imaging to determine tumour extent undergoing operation by a single surgeon between 1 January 2006 and 31 December 2009, the impact of magnetic resonance imaging findings was reviewed in terms of management alterations and their appropriateness. RESULTS: The most common indication for breast magnetic resonance imaging was the presence of multiple indeterminate shadows on ultrasound scans (53%), followed by ill-defined border of the main tumour on ultrasound scans (19%). In 66% (97 out of 147) of the patients, the extent of the operation was upgraded. Upgrading entailed: lumpectomy to wider lumpectomy (23 out of 97), lumpectomy to mastectomy (47 out of 97), lumpectomy to bilateral lumpectomy (15 out of 97), and other (12 out of 97). Mostly, these management changes were because magnetic resonance imaging showed more extensive disease (n=29), additional cancer foci (n=39), or contralateral disease (n=24). In five instances, upgrading was due to patient preference. In 34% (50 out of 147) of the patients, there was no change in the planned operation. Regarding 97 of the patients having altered management, in 12 the changes were considered inappropriately extensive (due to false-positive magnetic resonance imaging findings). In terms of magnetic resonance imaging detection of more extensive, multifocal, multicentric, or contralateral disease, the false-positive rate was 13% and false-negative rate 7%. Corresponding rates for sensitivity and specificity were 95% and 81%, using the final pathology as the gold standard. CONCLUSIONS: Preoperative magnetic resonance imaging had a clinically significant and mostly correct impact on management plans. Magnetic resonance imaging should be included as part of the preoperative investigation in patients planned for breast-conserving surgery, in whom there are doubts about the extent of the tumours based on conventional assessment.

De Garengeot's hernia: an unusual right groin mass due to acute appendicitis in an incarcerated femoral hernia.

The presence of an acutely inflamed vermiform appendix in a femoral hernia sac is extremely rare; the condition is termed De Garengeot's hernia. Here we describe an elderly patient for whom preoperative computed tomography aided the diagnosis of this rare entity. This Chinese woman had presented with a painful right groin mass. The patient successfully underwent an emergency appendicectomy and primary femoral hernia repair. Once diagnosed, it is imperative to follow key surgical principles to limit the spread of infection.

Automatic measurement of volume percentage stroma in endometrial images using texture segmentation.

The popularity of digital microscopy and tissue microarrays allow the use of high-throughput imaging for pathology research. To coordinate with this new technique, it is essential to automate the process of extracting information from such high amount of images. In this paper, we present a new model called the Subspace Mumford-Shah model for texture segmentation of microscopic endometrial images. The model incorporates subspace clustering techniques into a Mumford-Shah model to solve texture segmentation problems. The method first uses a supervised procedure to determine several optimal subspaces. These subspaces are then embedded into a Mumford-Shah objective function so that each segment of the optimal partition is homogeneous in its own subspace. The method outperforms a widely used method in bioimaging community called k-means segmentation since it can separate textures which are less separated in the full feature space, which confirm the usefulness of subspace clustering in texture segmentation. Experimental results also show that the proposed method is well performed on diagnosing premalignant endometrial disease and is very practical for segmenting image set sharing similar properties.

Cardiopulmonary manifestations of portovenous shunts from congenital absence of the portal vein: pulmonary hypertension and pulmonary vascular dilatation.

HPS and PPHTN are unusual and challenging pulmonary manifestations of liver disease. We report two pediatric cases in association with heterotaxy polysplenia syndrome and congenital absence of the portal vein. Both patients were symptomatic and hemodynamically compromised and required aggressive medical therapy. One patient with PPHTN alone achieved a successful liver transplant. The second child presented with combined HPS and PPHTN and exhibited a different evolution of pulmonary vascular disease. These cases illustrate associations that must be entertained in the setting of heterotaxy syndrome, cyanosis, or pulmonary hypertension and how strategic medical combined with surgical management can provide a good outcome.

Human CD4 restores normal T cell development and function in mice deficient in murine CD4.

The ability of a human coreceptor to function in mice was investigated by generating human CD4 (hCD4)-expressing transgenic mice on a mouse CD4-deficient (mCD4-/-) background. From developing thymocyte to matured T lymphocyte functions, hCD4 was shown to be physiologically active. By examining the expansion and deletion of specific V beta T cell families in mutated mice with and without hCD4, it was found that hCD4 can participate in positive and negative selection. Mature hCD4 single positive cells also were found in the periphery and they were shown to restore MHC class II-restricted alloreactive and antigen-specific T cell responses that were deficient in the mCD4 (-/-) mice. In addition, these hCD4 reconstituted mice can generate a secondary immunoglobulin G humoral response matching that of mCD4 wild-type mice. The fact that human CD4 is functional in mice and can be studied in the absence of murine CD4 should facilitate studies of human CD4 activity in general and human immunodeficiency virus 1 gp120-mediated pathogenesis in acquired immune deficiency syndrome specifically.

Human CD4-major histocompatibility complex class II (DQw6) transgenic mice in an endogenous CD4/CD8-deficient background: reconstitution of phenotype and human-restricted function.

To reconstitute the human immune system in mice, transgenic mice expressing human CD4 and human major histocompatibility complex (MHC) class II (DQw6) molecules in an endogenous CD4- and CD8-deficient background (mCD4/8-/-), after homologous recombination, have been generated. We report that expression of human CD4 molecule in mCD4/8-/- mice rescues thymocyte development and completely restores the T cell compartment in peripheral lymphoid organs. Upon vesicular stomatitis virus (VSV) challenge, the reconstituted mature T cell population effectively provide T help to B cells in immunoglobulin class switching from IgM to specific IgG-neutralizing antibodies. Human CD4+DQw6+ double transgenic mice are tolerant to DQw6 and the DQw6 molecule functions in antigen presentation, effectively generating a human MHC class II-restricted T cell response to streptococcal M6C2 peptide. These data show that both the hCD4 and DQw6 molecules are functional in mCD4/8-/- mice, fully and stably reconstituting this limb of the human immune system in mice. This animal model provides a powerful in vivo tool to dissect the human CD4-human class II MHC interaction, especially its role in human autoimmune diseases, superantigen-mediated diseases, and acquired immunodeficiency syndrome (AIDS).

Restricting the means of suicide by charcoal burning.

We conducted an exploratory controlled trial to examine the efficacy of restricting access to charcoal in preventing suicides from carbon monoxide poisoning by charcoal burning in Hong Kong. All charcoal packs were removed from the open shelves of major retail outlets in the intervention region for 12 months; in the control region, charcoal packs were displayed as usual. The suicide rate from charcoal burning was reduced by a statistically significant margin in the intervention region (P<0.05) but not in the control region. We observed no significant change in the suicide rate using other methods in either location.

High frequency plant regeneration from mature seed of elite, recalcitrant Malaysian indica rice ( Oryza sativa L.) CV. MR 219.

An efficient in vitro plant regeneration system was established for elite, recalcitrant Malaysian indica rice, Oryza sativa L. CV. MR 219 using mature seeds as explant on Murashige and Skoog and Chu N6 media containing 2,4-dichlorophenoxy acetic acid and kinetin either alone or in different combinations. L-proline, casein hydrolysate and L-glutamine were added to callus induction media for enhancement of embryogenic callus induction. The highest frequency of friable callus induction (84%) was observed in N6 medium containing 2.5 mg l(-1) 2,4-dichlorophenoxy acetic acid, 0.2 mg l(-1) kinetin, 2.5 mg l(-1) L-proline, 300 mg l(-1) casein hydrolysate, 20 mg l(-1) L-glutamine and 30 g l(-1) sucrose under culture in continuous lighting conditions. The maximum regeneration frequency (71%) was observed, when 30-day-old N6 friable calli were cultured on MS medium supplemented with 3 mg l(-1) 6-benzyl aminopurine, 1 mg l(-1) naphthalene acetic acid, 2.5 mg l(-1) L-proline, 300 mg l(-1) casein hydrolysate and 3% maltose. Developed shoots were rooted in half strength MS medium supplemented with 2% sucrose and were successfully transplanted to soil with 95% survival. This protocol may be used for other recalcitrant indica rice genotypes and to transfer desirable genes in to Malaysian indica rice cultivar MR219 for crop improvement.

Use of magnetic resonance imaging in evaluation of placental invasion.

AIM: To review and describe the magnetic resonance imaging (MRI) features in patients with suspected placental invasion and correlate the findings with surgery and pathology findings. MATERIALS AND METHODS: A retrospective review was undertaken of the MRI images of seven consecutive patients with ultrasound findings suspicious for placental invasion. Two experienced MRI radiologists, blinded to the pathology and surgery findings, reviewed the MRI. The pathology or surgical findings were used as the reference standard to establish accuracy and concordance with the MRI findings. RESULTS: Three MRI features described in an earlier series were consistently present in the patients with placental invasion: lower uterine bulging, heterogeneous placenta, and dark intraplacental linear bands on T2-weighted images. CONCLUSION: MRI features, which were described in patients with placental invasion in an earlier series, were useful in establishing the presence and depth of placental invasion.

Population pharmacokinetics of caffeine in healthy male adults using mixed-effects models.

OBJECTIVE: Caffeine has been shown to maintain or improve the performance of individuals, but its pharmacokinetic profile for Asians has not been well characterized. In this study, a population pharmacokinetic model for describing the pharmacokinetics of caffeine in Singapore males was developed. The data were also analysed using non-compartmental models. METHODS: Data gathered from 59 male volunteers, who each ingested a single caffeine capsule in two clinical trials (3 or 5 mg/kg), were analysed via non-linear mixed-effects modelling. The participants' covariates, including age, body weight, and regularity of caffeinated-beverage consumption or smoking, were analysed in a stepwise fashion to identify their potential influence on caffeine pharmacokinetics. The final pharmacostatistical model was then subjected to stochastic simulation to predict the plasma concentrations of caffeine after oral (204, 340 and 476 mg) dosing regimens (repeated dosing every 6, 8 or 12 h) over a hypothetical 3-day period. RESULTS: The data were best described by a one-compartmental model with first-order absorption and first-order elimination. Smoking status was an influential covariate for clearance: clearance (mL/min) = 110*SMOKE + 114, where SMOKE was 0 and 1 for the non-smoker and the smoker respectively. Interoccasion variability was smaller compared to interindividual variability in clearance, volume and absorption rate (27% vs. 33%, 10% vs. 15% and 23% vs. 51% respectively). The extrapolated elimination half-lives of caffeine in the non-smokers and the smokers were 4.3 +/- 1.5 and 3.0 +/- 0.7 h respectively. Dosing simulations indicated that dosing regimens of 340 mg (repeated every 8 h) and 476 mg (repeated every 6 h) should achieve population-averaged caffeine concentrations within the reported beneficial range (4.5-9 microg/mL) in the non-smokers and the smokers respectively over 72 h. CONCLUSION: The population pharmacokinetic model satisfactorily described the disposition and variability of caffeine in the data. Mixed-effects modelling showed that the dose of caffeine depended on cigarette smoking status.

An integrative suicide prevention program for visitor charcoal burning suicide and suicide pact.

An integrative suicide prevention program was implemented to tackle an outbreak of visitor charcoal burning suicides in Cheung Chau, an island in Hong Kong, in 2002. This study evaluated the effectiveness of the program. The numbers of visitor suicides reduced from 37 deaths in the 51 months prior to program implementation to 6 deaths in the 42 months post-implementation period. The number of visitor suicide pacts decreased from 7 pacts (15 individuals) to 1 pact (2 individuals). No statistically significant differences in the numbers of visitor suicide attempts and resident suicides were observed in the two time periods. No statistically significant changes in visitor suicides during the study period were observed on the comparison islands. The consistency and timing of reduction in visitor suicides correlated with the development and delivery of the integrative program on the intervention island, suggesting a causal association between program delivery and reduction of visitor suicides. The possibility of displacement seems small because there was no increase in visitor suicides on the comparison islands during the study period. This integrative approach in preventing target-specific suicides may serve as an example for other communities to develop suicide prevention programs that make use of the existing local resources.